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// SPDX-License-Identifier: GPL-2.0
/*
* SLUB: A slab allocator that limits cache line use instead of queuing
* objects in per cpu and per node lists.
*
* The allocator synchronizes using per slab locks or atomic operations
* and only uses a centralized lock to manage a pool of partial slabs.
*
* (C) 2007 SGI, Christoph Lameter
* (C) 2011 Linux Foundation, Christoph Lameter
*/
#include <linux/mm.h>
#include <linux/swap.h> /* mm_account_reclaimed_pages() */
#include <linux/module.h>
#include <linux/bit_spinlock.h>
#include <linux/interrupt.h>
#include <linux/swab.h>
#include <linux/bitops.h>
#include <linux/slab.h>
#include "slab.h"
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/kasan.h>
#include <linux/kmsan.h>
#include <linux/cpu.h>
#include <linux/cpuset.h>
#include <linux/mempolicy.h>
#include <linux/ctype.h>
#include <linux/stackdepot.h>
#include <linux/debugobjects.h>
#include <linux/kallsyms.h>
#include <linux/kfence.h>
#include <linux/memory.h>
#include <linux/math64.h>
#include <linux/fault-inject.h>
#include <linux/stacktrace.h>
#include <linux/prefetch.h>
#include <linux/memcontrol.h>
#include <linux/random.h>
#include <kunit/test.h>
#include <kunit/test-bug.h>
#include <linux/sort.h>
#include <linux/debugfs.h>
#include <trace/events/kmem.h>
#include "internal.h"
/*
* Lock order:
* 1. slab_mutex (Global Mutex)
* 2. node->list_lock (Spinlock)
* 3. kmem_cache->cpu_slab->lock (Local lock)
* 4. slab_lock(slab) (Only on some arches)
* 5. object_map_lock (Only for debugging)
*
* slab_mutex
*
* The role of the slab_mutex is to protect the list of all the slabs
* and to synchronize major metadata changes to slab cache structures.
* Also synchronizes memory hotplug callbacks.
*
* slab_lock
*
* The slab_lock is a wrapper around the page lock, thus it is a bit
* spinlock.
*
* The slab_lock is only used on arches that do not have the ability
* to do a cmpxchg_double. It only protects:
*
* A. slab->freelist -> List of free objects in a slab
* B. slab->inuse -> Number of objects in use
* C. slab->objects -> Number of objects in slab
* D. slab->frozen -> frozen state
*
* Frozen slabs
*
* If a slab is frozen then it is exempt from list management. It is not
* on any list except per cpu partial list. The processor that froze the
* slab is the one who can perform list operations on the slab. Other
* processors may put objects onto the freelist but the processor that
* froze the slab is the only one that can retrieve the objects from the
* slab's freelist.
*
* list_lock
*
* The list_lock protects the partial and full list on each node and
* the partial slab counter. If taken then no new slabs may be added or
* removed from the lists nor make the number of partial slabs be modified.
* (Note that the total number of slabs is an atomic value that may be
* modified without taking the list lock).
*
* The list_lock is a centralized lock and thus we avoid taking it as
* much as possible. As long as SLUB does not have to handle partial
* slabs, operations can continue without any centralized lock. F.e.
* allocating a long series of objects that fill up slabs does not require
* the list lock.
*
* For debug caches, all allocations are forced to go through a list_lock
* protected region to serialize against concurrent validation.
*
* cpu_slab->lock local lock
*
* This locks protect slowpath manipulation of all kmem_cache_cpu fields
* except the stat counters. This is a percpu structure manipulated only by
* the local cpu, so the lock protects against being preempted or interrupted
* by an irq. Fast path operations rely on lockless operations instead.
*
* On PREEMPT_RT, the local lock neither disables interrupts nor preemption
* which means the lockless fastpath cannot be used as it might interfere with
* an in-progress slow path operations. In this case the local lock is always
* taken but it still utilizes the freelist for the common operations.
*
* lockless fastpaths
*
* The fast path allocation (slab_alloc_node()) and freeing (do_slab_free())
* are fully lockless when satisfied from the percpu slab (and when
* cmpxchg_double is possible to use, otherwise slab_lock is taken).
* They also don't disable preemption or migration or irqs. They rely on
* the transaction id (tid) field to detect being preempted or moved to
* another cpu.
*
* irq, preemption, migration considerations
*
* Interrupts are disabled as part of list_lock or local_lock operations, or
* around the slab_lock operation, in order to make the slab allocator safe
* to use in the context of an irq.
*
* In addition, preemption (or migration on PREEMPT_RT) is disabled in the
* allocation slowpath, bulk allocation, and put_cpu_partial(), so that the
* local cpu doesn't change in the process and e.g. the kmem_cache_cpu pointer
* doesn't have to be revalidated in each section protected by the local lock.
*
* SLUB assigns one slab for allocation to each processor.
* Allocations only occur from these slabs called cpu slabs.
*
* Slabs with free elements are kept on a partial list and during regular
* operations no list for full slabs is used. If an object in a full slab is
* freed then the slab will show up again on the partial lists.
* We track full slabs for debugging purposes though because otherwise we
* cannot scan all objects.
*
* Slabs are freed when they become empty. Teardown and setup is
* minimal so we rely on the page allocators per cpu caches for
* fast frees and allocs.
*
* slab->frozen The slab is frozen and exempt from list processing.
* This means that the slab is dedicated to a purpose
* such as satisfying allocations for a specific
* processor. Objects may be freed in the slab while
* it is frozen but slab_free will then skip the usual
* list operations. It is up to the processor holding
* the slab to integrate the slab into the slab lists
* when the slab is no longer needed.
*
* One use of this flag is to mark slabs that are
* used for allocations. Then such a slab becomes a cpu
* slab. The cpu slab may be equipped with an additional
* freelist that allows lockless access to
* free objects in addition to the regular freelist
* that requires the slab lock.
*
* SLAB_DEBUG_FLAGS Slab requires special handling due to debug
* options set. This moves slab handling out of
* the fast path and disables lockless freelists.
*/
/*
* We could simply use migrate_disable()/enable() but as long as it's a
* function call even on !PREEMPT_RT, use inline preempt_disable() there.
*/
#ifndef CONFIG_PREEMPT_RT
#define slub_get_cpu_ptr(var) get_cpu_ptr(var)
#define slub_put_cpu_ptr(var) put_cpu_ptr(var)
#define USE_LOCKLESS_FAST_PATH() (true)
#else
#define slub_get_cpu_ptr(var) \
({ \
migrate_disable(); \
this_cpu_ptr(var); \
})
#define slub_put_cpu_ptr(var) \
do { \
(void)(var); \
migrate_enable(); \
} while (0)
#define USE_LOCKLESS_FAST_PATH() (false)
#endif
#ifndef CONFIG_SLUB_TINY
#define __fastpath_inline __always_inline
#else
#define __fastpath_inline
#endif
#ifdef CONFIG_SLUB_DEBUG
#ifdef CONFIG_SLUB_DEBUG_ON
DEFINE_STATIC_KEY_TRUE(slub_debug_enabled);
#else
DEFINE_STATIC_KEY_FALSE(slub_debug_enabled);
#endif
#endif /* CONFIG_SLUB_DEBUG */
/* Structure holding parameters for get_partial() call chain */
struct partial_context {
struct slab **slab;
gfp_t flags;
unsigned int orig_size;
};
static inline bool kmem_cache_debug(struct kmem_cache *s)
{
return kmem_cache_debug_flags(s, SLAB_DEBUG_FLAGS);
}
static inline bool slub_debug_orig_size(struct kmem_cache *s)
{
return (kmem_cache_debug_flags(s, SLAB_STORE_USER) &&
(s->flags & SLAB_KMALLOC));
}
void *fixup_red_left(struct kmem_cache *s, void *p)
{
if (kmem_cache_debug_flags(s, SLAB_RED_ZONE))
p += s->red_left_pad;
return p;
}
static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s)
{
#ifdef CONFIG_SLUB_CPU_PARTIAL
return !kmem_cache_debug(s);
#else
return false;
#endif
}
/*
* Issues still to be resolved:
*
* - Support PAGE_ALLOC_DEBUG. Should be easy to do.
*
* - Variable sizing of the per node arrays
*/
/* Enable to log cmpxchg failures */
#undef SLUB_DEBUG_CMPXCHG
#ifndef CONFIG_SLUB_TINY
/*
* Minimum number of partial slabs. These will be left on the partial
* lists even if they are empty. kmem_cache_shrink may reclaim them.
*/
#define MIN_PARTIAL 5
/*
* Maximum number of desirable partial slabs.
* The existence of more partial slabs makes kmem_cache_shrink
* sort the partial list by the number of objects in use.
*/
#define MAX_PARTIAL 10
#else
#define MIN_PARTIAL 0
#define MAX_PARTIAL 0
#endif
#define DEBUG_DEFAULT_FLAGS (SLAB_CONSISTENCY_CHECKS | SLAB_RED_ZONE | \
SLAB_POISON | SLAB_STORE_USER)
/*
* These debug flags cannot use CMPXCHG because there might be consistency
* issues when checking or reading debug information
*/
#define SLAB_NO_CMPXCHG (SLAB_CONSISTENCY_CHECKS | SLAB_STORE_USER | \
SLAB_TRACE)
/*
* Debugging flags that require metadata to be stored in the slab. These get
* disabled when slub_debug=O is used and a cache's min order increases with
* metadata.
*/
#define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
#define OO_SHIFT 16
#define OO_MASK ((1 << OO_SHIFT) - 1)
#define MAX_OBJS_PER_PAGE 32767 /* since slab.objects is u15 */
/* Internal SLUB flags */
/* Poison object */
#define __OBJECT_POISON ((slab_flags_t __force)0x80000000U)
/* Use cmpxchg_double */
#ifdef system_has_freelist_aba
#define __CMPXCHG_DOUBLE ((slab_flags_t __force)0x40000000U)
#else
#define __CMPXCHG_DOUBLE ((slab_flags_t __force)0U)
#endif
/*
* Tracking user of a slab.
*/
#define TRACK_ADDRS_COUNT 16
struct track {
unsigned long addr; /* Called from address */
#ifdef CONFIG_STACKDEPOT
depot_stack_handle_t handle;
#endif
int cpu; /* Was running on cpu */
int pid; /* Pid context */
unsigned long when; /* When did the operation occur */
};
enum track_item { TRACK_ALLOC, TRACK_FREE };
#ifdef SLAB_SUPPORTS_SYSFS
static int sysfs_slab_add(struct kmem_cache *);
static int sysfs_slab_alias(struct kmem_cache *, const char *);
#else
static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
{ return 0; }
#endif
#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_SLUB_DEBUG)
static void debugfs_slab_add(struct kmem_cache *);
#else
static inline void debugfs_slab_add(struct kmem_cache *s) { }
#endif
static inline void stat(const struct kmem_cache *s, enum stat_item si)
{
#ifdef CONFIG_SLUB_STATS
/*
* The rmw is racy on a preemptible kernel but this is acceptable, so
* avoid this_cpu_add()'s irq-disable overhead.
*/
raw_cpu_inc(s->cpu_slab->stat[si]);
#endif
}
/*
* Tracks for which NUMA nodes we have kmem_cache_nodes allocated.
* Corresponds to node_state[N_NORMAL_MEMORY], but can temporarily
* differ during memory hotplug/hotremove operations.
* Protected by slab_mutex.
*/
static nodemask_t slab_nodes;
#ifndef CONFIG_SLUB_TINY
/*
* Workqueue used for flush_cpu_slab().
*/
static struct workqueue_struct *flushwq;
#endif
/********************************************************************
* Core slab cache functions
*******************************************************************/
/*
* freeptr_t represents a SLUB freelist pointer, which might be encoded
* and not dereferenceable if CONFIG_SLAB_FREELIST_HARDENED is enabled.
*/
typedef struct { unsigned long v; } freeptr_t;
/*
* Returns freelist pointer (ptr). With hardening, this is obfuscated
* with an XOR of the address where the pointer is held and a per-cache
* random number.
*/
static inline freeptr_t freelist_ptr_encode(const struct kmem_cache *s,
void *ptr, unsigned long ptr_addr)
{
unsigned long encoded;
#ifdef CONFIG_SLAB_FREELIST_HARDENED
encoded = (unsigned long)ptr ^ s->random ^ swab(ptr_addr);
#else
encoded = (unsigned long)ptr;
#endif
return (freeptr_t){.v = encoded};
}
static inline void *freelist_ptr_decode(const struct kmem_cache *s,
freeptr_t ptr, unsigned long ptr_addr)
{
void *decoded;
#ifdef CONFIG_SLAB_FREELIST_HARDENED
decoded = (void *)(ptr.v ^ s->random ^ swab(ptr_addr));
#else
decoded = (void *)ptr.v;
#endif
return decoded;
}
static inline void *get_freepointer(struct kmem_cache *s, void *object)
{
unsigned long ptr_addr;
freeptr_t p;
object = kasan_reset_tag(object);
ptr_addr = (unsigned long)object + s->offset;
p = *(freeptr_t *)(ptr_addr);
return freelist_ptr_decode(s, p, ptr_addr);
}
#ifndef CONFIG_SLUB_TINY
static void prefetch_freepointer(const struct kmem_cache *s, void *object)
{
prefetchw(object + s->offset);
}
#endif
/*
* When running under KMSAN, get_freepointer_safe() may return an uninitialized
* pointer value in the case the current thread loses the race for the next
* memory chunk in the freelist. In that case this_cpu_cmpxchg_double() in
* slab_alloc_node() will fail, so the uninitialized value won't be used, but
* KMSAN will still check all arguments of cmpxchg because of imperfect
* handling of inline assembly.
* To work around this problem, we apply __no_kmsan_checks to ensure that
* get_freepointer_safe() returns initialized memory.
*/
__no_kmsan_checks
static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
{
unsigned long freepointer_addr;
freeptr_t p;
if (!debug_pagealloc_enabled_static())
return get_freepointer(s, object);
object = kasan_reset_tag(object);
freepointer_addr = (unsigned long)object + s->offset;
copy_from_kernel_nofault(&p, (freeptr_t *)freepointer_addr, sizeof(p));
return freelist_ptr_decode(s, p, freepointer_addr);
}
static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
{
unsigned long freeptr_addr = (unsigned long)object + s->offset;
#ifdef CONFIG_SLAB_FREELIST_HARDENED
BUG_ON(object == fp); /* naive detection of double free or corruption */
#endif
freeptr_addr = (unsigned long)kasan_reset_tag((void *)freeptr_addr);
*(freeptr_t *)freeptr_addr = freelist_ptr_encode(s, fp, freeptr_addr);
}
/* Loop over all objects in a slab */
#define for_each_object(__p, __s, __addr, __objects) \
for (__p = fixup_red_left(__s, __addr); \
__p < (__addr) + (__objects) * (__s)->size; \
__p += (__s)->size)
static inline unsigned int order_objects(unsigned int order, unsigned int size)
{
return ((unsigned int)PAGE_SIZE << order) / size;
}
static inline struct kmem_cache_order_objects oo_make(unsigned int order,
unsigned int size)
{
struct kmem_cache_order_objects x = {
(order << OO_SHIFT) + order_objects(order, size)
};
return x;
}
static inline unsigned int oo_order(struct kmem_cache_order_objects x)
{
return x.x >> OO_SHIFT;
}
static inline unsigned int oo_objects(struct kmem_cache_order_objects x)
{
return x.x & OO_MASK;
}
#ifdef CONFIG_SLUB_CPU_PARTIAL
static void slub_set_cpu_partial(struct kmem_cache *s, unsigned int nr_objects)
{
unsigned int nr_slabs;
s->cpu_partial = nr_objects;
/*
* We take the number of objects but actually limit the number of
* slabs on the per cpu partial list, in order to limit excessive
* growth of the list. For simplicity we assume that the slabs will
* be half-full.
*/
nr_slabs = DIV_ROUND_UP(nr_objects * 2, oo_objects(s->oo));
s->cpu_partial_slabs = nr_slabs;
}
#else
static inline void
slub_set_cpu_partial(struct kmem_cache *s, unsigned int nr_objects)
{
}
#endif /* CONFIG_SLUB_CPU_PARTIAL */
/*
* Per slab locking using the pagelock
*/
static __always_inline void slab_lock(struct slab *slab)
{
struct page *page = slab_page(slab);
VM_BUG_ON_PAGE(PageTail(page), page);
bit_spin_lock(PG_locked, &page->flags);
}
static __always_inline void slab_unlock(struct slab *slab)
{
struct page *page = slab_page(slab);
VM_BUG_ON_PAGE(PageTail(page), page);
__bit_spin_unlock(PG_locked, &page->flags);
}
static inline bool
__update_freelist_fast(struct slab *slab,
void *freelist_old, unsigned long counters_old,
void *freelist_new, unsigned long counters_new)
{
#ifdef system_has_freelist_aba
freelist_aba_t old = { .freelist = freelist_old, .counter = counters_old };
freelist_aba_t new = { .freelist = freelist_new, .counter = counters_new };
return try_cmpxchg_freelist(&slab->freelist_counter.full, &old.full, new.full);
#else
return false;
#endif
}
static inline bool
__update_freelist_slow(struct slab *slab,
void *freelist_old, unsigned long counters_old,
void *freelist_new, unsigned long counters_new)
{
bool ret = false;
slab_lock(slab);
if (slab->freelist == freelist_old &&
slab->counters == counters_old) {
slab->freelist = freelist_new;
slab->counters = counters_new;
ret = true;
}
slab_unlock(slab);
return ret;
}
/*
* Interrupts must be disabled (for the fallback code to work right), typically
* by an _irqsave() lock variant. On PREEMPT_RT the preempt_disable(), which is
* part of bit_spin_lock(), is sufficient because the policy is not to allow any
* allocation/ free operation in hardirq context. Therefore nothing can
* interrupt the operation.
*/
static inline bool __slab_update_freelist(struct kmem_cache *s, struct slab *slab,
void *freelist_old, unsigned long counters_old,
void *freelist_new, unsigned long counters_new,
const char *n)
{
bool ret;
if (USE_LOCKLESS_FAST_PATH())
lockdep_assert_irqs_disabled();
if (s->flags & __CMPXCHG_DOUBLE) {
ret = __update_freelist_fast(slab, freelist_old, counters_old,
freelist_new, counters_new);
} else {
ret = __update_freelist_slow(slab, freelist_old, counters_old,
freelist_new, counters_new);
}
if (likely(ret))
return true;
cpu_relax();
stat(s, CMPXCHG_DOUBLE_FAIL);
#ifdef SLUB_DEBUG_CMPXCHG
pr_info("%s %s: cmpxchg double redo ", n, s->name);
#endif
return false;
}
static inline bool slab_update_freelist(struct kmem_cache *s, struct slab *slab,
void *freelist_old, unsigned long counters_old,
void *freelist_new, unsigned long counters_new,
const char *n)
{
bool ret;
if (s->flags & __CMPXCHG_DOUBLE) {
ret = __update_freelist_fast(slab, freelist_old, counters_old,
freelist_new, counters_new);
} else {
unsigned long flags;
local_irq_save(flags);
ret = __update_freelist_slow(slab, freelist_old, counters_old,
freelist_new, counters_new);
local_irq_restore(flags);
}
if (likely(ret))
return true;
cpu_relax();
stat(s, CMPXCHG_DOUBLE_FAIL);
#ifdef SLUB_DEBUG_CMPXCHG
pr_info("%s %s: cmpxchg double redo ", n, s->name);
#endif
return false;
}
#ifdef CONFIG_SLUB_DEBUG
static unsigned long object_map[BITS_TO_LONGS(MAX_OBJS_PER_PAGE)];
static DEFINE_SPINLOCK(object_map_lock);
static void __fill_map(unsigned long *obj_map, struct kmem_cache *s,
struct slab *slab)
{
void *addr = slab_address(slab);
void *p;
bitmap_zero(obj_map, slab->objects);
for (p = slab->freelist; p; p = get_freepointer(s, p))
set_bit(__obj_to_index(s, addr, p), obj_map);
}
#if IS_ENABLED(CONFIG_KUNIT)
static bool slab_add_kunit_errors(void)
{
struct kunit_resource *resource;
if (!kunit_get_current_test())
return false;
resource = kunit_find_named_resource(current->kunit_test, "slab_errors");
if (!resource)
return false;
(*(int *)resource->data)++;
kunit_put_resource(resource);
return true;
}
#else
static inline bool slab_add_kunit_errors(void) { return false; }
#endif
static inline unsigned int size_from_object(struct kmem_cache *s)
{
if (s->flags & SLAB_RED_ZONE)
return s->size - s->red_left_pad;
return s->size;
}
static inline void *restore_red_left(struct kmem_cache *s, void *p)
{
if (s->flags & SLAB_RED_ZONE)
p -= s->red_left_pad;
return p;
}
/*
* Debug settings:
*/
#if defined(CONFIG_SLUB_DEBUG_ON)
static slab_flags_t slub_debug = DEBUG_DEFAULT_FLAGS;
#else
static slab_flags_t slub_debug;
#endif
static char *slub_debug_string;
static int disable_higher_order_debug;
/*
* slub is about to manipulate internal object metadata. This memory lies
* outside the range of the allocated object, so accessing it would normally
* be reported by kasan as a bounds error. metadata_access_enable() is used
* to tell kasan that these accesses are OK.
*/
static inline void metadata_access_enable(void)
{
kasan_disable_current();
}
static inline void metadata_access_disable(void)
{
kasan_enable_current();
}
/*
* Object debugging
*/
/* Verify that a pointer has an address that is valid within a slab page */
static inline int check_valid_pointer(struct kmem_cache *s,
struct slab *slab, void *object)
{
void *base;
if (!object)
return 1;
base = slab_address(slab);
object = kasan_reset_tag(object);
object = restore_red_left(s, object);
if (object < base || object >= base + slab->objects * s->size ||
(object - base) % s->size) {
return 0;
}
return 1;
}
static void print_section(char *level, char *text, u8 *addr,
unsigned int length)
{
metadata_access_enable();
print_hex_dump(level, text, DUMP_PREFIX_ADDRESS,
16, 1, kasan_reset_tag((void *)addr), length, 1);
metadata_access_disable();
}
/*
* See comment in calculate_sizes().
*/
static inline bool freeptr_outside_object(struct kmem_cache *s)
{
return s->offset >= s->inuse;
}
/*
* Return offset of the end of info block which is inuse + free pointer if
* not overlapping with object.
*/
static inline unsigned int get_info_end(struct kmem_cache *s)
{
if (freeptr_outside_object(s))
return s->inuse + sizeof(void *);
else
return s->inuse;
}
static struct track *get_track(struct kmem_cache *s, void *object,
enum track_item alloc)
{
struct track *p;
p = object + get_info_end(s);
return kasan_reset_tag(p + alloc);
}
#ifdef CONFIG_STACKDEPOT
static noinline depot_stack_handle_t set_track_prepare(void)
{
depot_stack_handle_t handle;
unsigned long entries[TRACK_ADDRS_COUNT];
unsigned int nr_entries;
nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 3);
handle = stack_depot_save(entries, nr_entries, GFP_NOWAIT);
return handle;
}
#else
static inline depot_stack_handle_t set_track_prepare(void)
{
return 0;
}
#endif
static void set_track_update(struct kmem_cache *s, void *object,
enum track_item alloc, unsigned long addr,
depot_stack_handle_t handle)
{
struct track *p = get_track(s, object, alloc);
#ifdef CONFIG_STACKDEPOT
p->handle = handle;
#endif
p->addr = addr;
p->cpu = smp_processor_id();
p->pid = current->pid;
p->when = jiffies;
}
static __always_inline void set_track(struct kmem_cache *s, void *object,
enum track_item alloc, unsigned long addr)
{
depot_stack_handle_t handle = set_track_prepare();
set_track_update(s, object, alloc, addr, handle);
}
static void init_tracking(struct kmem_cache *s, void *object)
{
struct track *p;
if (!(s->flags & SLAB_STORE_USER))
return;
p = get_track(s, object, TRACK_ALLOC);
memset(p, 0, 2*sizeof(struct track));
}
static void print_track(const char *s, struct track *t, unsigned long pr_time)
{
depot_stack_handle_t handle __maybe_unused;
if (!t->addr)
return;
pr_err("%s in %pS age=%lu cpu=%u pid=%d\n",
s, (void *)t->addr, pr_time - t->when, t->cpu, t->pid);
#ifdef CONFIG_STACKDEPOT
handle = READ_ONCE(t->handle);
if (handle)
stack_depot_print(handle);
else
pr_err("object allocation/free stack trace missing\n");
#endif
}
void print_tracking(struct kmem_cache *s, void *object)
{
unsigned long pr_time = jiffies;
if (!(s->flags & SLAB_STORE_USER))
return;
print_track("Allocated", get_track(s, object, TRACK_ALLOC), pr_time);
print_track("Freed", get_track(s, object, TRACK_FREE), pr_time);
}
static void print_slab_info(const struct slab *slab)
{
struct folio *folio = (struct folio *)slab_folio(slab);
pr_err("Slab 0x%p objects=%u used=%u fp=0x%p flags=%pGp\n",
slab, slab->objects, slab->inuse, slab->freelist,
folio_flags(folio, 0));
}
/*
* kmalloc caches has fixed sizes (mostly power of 2), and kmalloc() API
* family will round up the real request size to these fixed ones, so
* there could be an extra area than what is requested. Save the original
* request size in the meta data area, for better debug and sanity check.
*/
static inline void set_orig_size(struct kmem_cache *s,
void *object, unsigned int orig_size)
{
void *p = kasan_reset_tag(object);
if (!slub_debug_orig_size(s))
return;
#ifdef CONFIG_KASAN_GENERIC
/*
* KASAN could save its free meta data in object's data area at
* offset 0, if the size is larger than 'orig_size', it will
* overlap the data redzone in [orig_size+1, object_size], and
* the check should be skipped.
*/
if (kasan_metadata_size(s, true) > orig_size)
orig_size = s->object_size;
#endif
p += get_info_end(s);
p += sizeof(struct track) * 2;
*(unsigned int *)p = orig_size;
}
static inline unsigned int get_orig_size(struct kmem_cache *s, void *object)
{
void *p = kasan_reset_tag(object);
if (!slub_debug_orig_size(s))
return s->object_size;
p += get_info_end(s);
p += sizeof(struct track) * 2;
return *(unsigned int *)p;
}
void skip_orig_size_check(struct kmem_cache *s, const void *object)
{
set_orig_size(s, (void *)object, s->object_size);
}
static void slab_bug(struct kmem_cache *s, char *fmt, ...)
{
struct va_format vaf;
va_list args;
va_start(args, fmt);
vaf.fmt = fmt;
vaf.va = &args;
pr_err("=============================================================================\n");
pr_err("BUG %s (%s): %pV\n", s->name, print_tainted(), &vaf);
pr_err("-----------------------------------------------------------------------------\n\n");
va_end(args);
}
__printf(2, 3)
static void slab_fix(struct kmem_cache *s, char *fmt, ...)
{
struct va_format vaf;
va_list args;
if (slab_add_kunit_errors())
return;
va_start(args, fmt);
vaf.fmt = fmt;
vaf.va = &args;
pr_err("FIX %s: %pV\n", s->name, &vaf);
va_end(args);
}
static void print_trailer(struct kmem_cache *s, struct slab *slab, u8 *p)
{
unsigned int off; /* Offset of last byte */
u8 *addr = slab_address(slab);
print_tracking(s, p);
print_slab_info(slab);
pr_err("Object 0x%p @offset=%tu fp=0x%p\n\n",
p, p - addr, get_freepointer(s, p));
if (s->flags & SLAB_RED_ZONE)
print_section(KERN_ERR, "Redzone ", p - s->red_left_pad,
s->red_left_pad);
else if (p > addr + 16)
print_section(KERN_ERR, "Bytes b4 ", p - 16, 16);
print_section(KERN_ERR, "Object ", p,
min_t(unsigned int, s->object_size, PAGE_SIZE));
if (s->flags & SLAB_RED_ZONE)
print_section(KERN_ERR, "Redzone ", p + s->object_size,
s->inuse - s->object_size);
off = get_info_end(s);
if (s->flags & SLAB_STORE_USER)
off += 2 * sizeof(struct track);
if (slub_debug_orig_size(s))
off += sizeof(unsigned int);
off += kasan_metadata_size(s, false);
if (off != size_from_object(s))
/* Beginning of the filler is the free pointer */
print_section(KERN_ERR, "Padding ", p + off,
size_from_object(s) - off);
dump_stack();
}
static void object_err(struct kmem_cache *s, struct slab *slab,
u8 *object, char *reason)
{
if (slab_add_kunit_errors())
return;
slab_bug(s, "%s", reason);
print_trailer(s, slab, object);
add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
}
static bool freelist_corrupted(struct kmem_cache *s, struct slab *slab,
void **freelist, void *nextfree)
{
if ((s->flags & SLAB_CONSISTENCY_CHECKS) &&
!check_valid_pointer(s, slab, nextfree) && freelist) {
object_err(s, slab, *freelist, "Freechain corrupt");
*freelist = NULL;
slab_fix(s, "Isolate corrupted freechain");
return true;
}
return false;
}
static __printf(3, 4) void slab_err(struct kmem_cache *s, struct slab *slab,
const char *fmt, ...)
{
va_list args;
char buf[100];
if (slab_add_kunit_errors())
return;
va_start(args, fmt);
vsnprintf(buf, sizeof(buf), fmt, args);
va_end(args);
slab_bug(s, "%s", buf);
print_slab_info(slab);
dump_stack();
add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
}
static void init_object(struct kmem_cache *s, void *object, u8 val)
{
u8 *p = kasan_reset_tag(object);
unsigned int poison_size = s->object_size;
if (s->flags & SLAB_RED_ZONE) {
memset(p - s->red_left_pad, val, s->red_left_pad);
if (slub_debug_orig_size(s) && val == SLUB_RED_ACTIVE) {
/*
* Redzone the extra allocated space by kmalloc than
* requested, and the poison size will be limited to
* the original request size accordingly.
*/
poison_size = get_orig_size(s, object);
}
}
if (s->flags & __OBJECT_POISON) {
memset(p, POISON_FREE, poison_size - 1);
p[poison_size - 1] = POISON_END;
}
if (s->flags & SLAB_RED_ZONE)
memset(p + poison_size, val, s->inuse - poison_size);
}
static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
void *from, void *to)
{
slab_fix(s, "Restoring %s 0x%p-0x%p=0x%x", message, from, to - 1, data);
memset(from, data, to - from);
}
static int check_bytes_and_report(struct kmem_cache *s, struct slab *slab,
u8 *object, char *what,
u8 *start, unsigned int value, unsigned int bytes)
{
u8 *fault;
u8 *end;
u8 *addr = slab_address(slab);
metadata_access_enable();
fault = memchr_inv(kasan_reset_tag(start), value, bytes);
metadata_access_disable();
if (!fault)
return 1;
end = start + bytes;
while (end > fault && end[-1] == value)
end--;
if (slab_add_kunit_errors())
goto skip_bug_print;
slab_bug(s, "%s overwritten", what);
pr_err("0x%p-0x%p @offset=%tu. First byte 0x%x instead of 0x%x\n",
fault, end - 1, fault - addr,
fault[0], value);
print_trailer(s, slab, object);
add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
skip_bug_print:
restore_bytes(s, what, value, fault, end);
return 0;
}
/*
* Object layout:
*
* object address
* Bytes of the object to be managed.
* If the freepointer may overlay the object then the free
* pointer is at the middle of the object.
*
* Poisoning uses 0x6b (POISON_FREE) and the last byte is
* 0xa5 (POISON_END)
*
* object + s->object_size
* Padding to reach word boundary. This is also used for Redzoning.
* Padding is extended by another word if Redzoning is enabled and
* object_size == inuse.
*
* We fill with 0xbb (RED_INACTIVE) for inactive objects and with
* 0xcc (RED_ACTIVE) for objects in use.
*
* object + s->inuse
* Meta data starts here.
*
* A. Free pointer (if we cannot overwrite object on free)
* B. Tracking data for SLAB_STORE_USER
* C. Original request size for kmalloc object (SLAB_STORE_USER enabled)
* D. Padding to reach required alignment boundary or at minimum
* one word if debugging is on to be able to detect writes
* before the word boundary.
*
* Padding is done using 0x5a (POISON_INUSE)
*
* object + s->size
* Nothing is used beyond s->size.
*
* If slabcaches are merged then the object_size and inuse boundaries are mostly
* ignored. And therefore no slab options that rely on these boundaries
* may be used with merged slabcaches.
*/
static int check_pad_bytes(struct kmem_cache *s, struct slab *slab, u8 *p)
{
unsigned long off = get_info_end(s); /* The end of info */
if (s->flags & SLAB_STORE_USER) {
/* We also have user information there */
off += 2 * sizeof(struct track);
if (s->flags & SLAB_KMALLOC)
off += sizeof(unsigned int);
}
off += kasan_metadata_size(s, false);
if (size_from_object(s) == off)
return 1;
return check_bytes_and_report(s, slab, p, "Object padding",
p + off, POISON_INUSE, size_from_object(s) - off);
}
/* Check the pad bytes at the end of a slab page */
static void slab_pad_check(struct kmem_cache *s, struct slab *slab)
{
u8 *start;
u8 *fault;
u8 *end;
u8 *pad;
int length;
int remainder;
if (!(s->flags & SLAB_POISON))
return;
start = slab_address(slab);
length = slab_size(slab);
end = start + length;
remainder = length % s->size;
if (!remainder)
return;
pad = end - remainder;
metadata_access_enable();
fault = memchr_inv(kasan_reset_tag(pad), POISON_INUSE, remainder);
metadata_access_disable();
if (!fault)
return;
while (end > fault && end[-1] == POISON_INUSE)
end--;
slab_err(s, slab, "Padding overwritten. 0x%p-0x%p @offset=%tu",
fault, end - 1, fault - start);
print_section(KERN_ERR, "Padding ", pad, remainder);
restore_bytes(s, "slab padding", POISON_INUSE, fault, end);
}
static int check_object(struct kmem_cache *s, struct slab *slab,
void *object, u8 val)
{
u8 *p = object;
u8 *endobject = object + s->object_size;
unsigned int orig_size;
if (s->flags & SLAB_RED_ZONE) {
if (!check_bytes_and_report(s, slab, object, "Left Redzone",
object - s->red_left_pad, val, s->red_left_pad))
return 0;
if (!check_bytes_and_report(s, slab, object, "Right Redzone",
endobject, val, s->inuse - s->object_size))
return 0;
if (slub_debug_orig_size(s) && val == SLUB_RED_ACTIVE) {
orig_size = get_orig_size(s, object);
if (s->object_size > orig_size &&
!check_bytes_and_report(s, slab, object,
"kmalloc Redzone", p + orig_size,
val, s->object_size - orig_size)) {
return 0;
}
}
} else {
if ((s->flags & SLAB_POISON) && s->object_size < s->inuse) {
check_bytes_and_report(s, slab, p, "Alignment padding",
endobject, POISON_INUSE,
s->inuse - s->object_size);
}
}
if (s->flags & SLAB_POISON) {
if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) &&
(!check_bytes_and_report(s, slab, p, "Poison", p,
POISON_FREE, s->object_size - 1) ||
!check_bytes_and_report(s, slab, p, "End Poison",
p + s->object_size - 1, POISON_END, 1)))
return 0;
/*
* check_pad_bytes cleans up on its own.
*/
check_pad_bytes(s, slab, p);
}
if (!freeptr_outside_object(s) && val == SLUB_RED_ACTIVE)
/*
* Object and freepointer overlap. Cannot check
* freepointer while object is allocated.
*/
return 1;
/* Check free pointer validity */
if (!check_valid_pointer(s, slab, get_freepointer(s, p))) {
object_err(s, slab, p, "Freepointer corrupt");
/*
* No choice but to zap it and thus lose the remainder
* of the free objects in this slab. May cause
* another error because the object count is now wrong.
*/
set_freepointer(s, p, NULL);
return 0;
}
return 1;
}
static int check_slab(struct kmem_cache *s, struct slab *slab)
{
int maxobj;
if (!folio_test_slab(slab_folio(slab))) {
slab_err(s, slab, "Not a valid slab page");
return 0;
}
maxobj = order_objects(slab_order(slab), s->size);
if (slab->objects > maxobj) {
slab_err(s, slab, "objects %u > max %u",
slab->objects, maxobj);
return 0;
}
if (slab->inuse > slab->objects) {
slab_err(s, slab, "inuse %u > max %u",
slab->inuse, slab->objects);
return 0;
}
/* Slab_pad_check fixes things up after itself */
slab_pad_check(s, slab);
return 1;
}
/*
* Determine if a certain object in a slab is on the freelist. Must hold the
* slab lock to guarantee that the chains are in a consistent state.
*/
static int on_freelist(struct kmem_cache *s, struct slab *slab, void *search)
{
int nr = 0;
void *fp;
void *object = NULL;
int max_objects;
fp = slab->freelist;
while (fp && nr <= slab->objects) {
if (fp == search)
return 1;
if (!check_valid_pointer(s, slab, fp)) {
if (object) {
object_err(s, slab, object,
"Freechain corrupt");
set_freepointer(s, object, NULL);
} else {
slab_err(s, slab, "Freepointer corrupt");
slab->freelist = NULL;
slab->inuse = slab->objects;
slab_fix(s, "Freelist cleared");
return 0;
}
break;
}
object = fp;
fp = get_freepointer(s, object);
nr++;
}
max_objects = order_objects(slab_order(slab), s->size);
if (max_objects > MAX_OBJS_PER_PAGE)
max_objects = MAX_OBJS_PER_PAGE;
if (slab->objects != max_objects) {
slab_err(s, slab, "Wrong number of objects. Found %d but should be %d",
slab->objects, max_objects);
slab->objects = max_objects;
slab_fix(s, "Number of objects adjusted");
}
if (slab->inuse != slab->objects - nr) {
slab_err(s, slab, "Wrong object count. Counter is %d but counted were %d",
slab->inuse, slab->objects - nr);
slab->inuse = slab->objects - nr;
slab_fix(s, "Object count adjusted");
}
return search == NULL;
}
static void trace(struct kmem_cache *s, struct slab *slab, void *object,
int alloc)
{
if (s->flags & SLAB_TRACE) {
pr_info("TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
s->name,
alloc ? "alloc" : "free",
object, slab->inuse,
slab->freelist);
if (!alloc)
print_section(KERN_INFO, "Object ", (void *)object,
s->object_size);
dump_stack();
}
}
/*
* Tracking of fully allocated slabs for debugging purposes.
*/
static void add_full(struct kmem_cache *s,
struct kmem_cache_node *n, struct slab *slab)
{
if (!(s->flags & SLAB_STORE_USER))
return;
lockdep_assert_held(&n->list_lock);
list_add(&slab->slab_list, &n->full);
}
static void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, struct slab *slab)
{
if (!(s->flags & SLAB_STORE_USER))
return;
lockdep_assert_held(&n->list_lock);
list_del(&slab->slab_list);
}
static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
{
return atomic_long_read(&n->nr_slabs);
}
static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
{
struct kmem_cache_node *n = get_node(s, node);
/*
* May be called early in order to allocate a slab for the
* kmem_cache_node structure. Solve the chicken-egg
* dilemma by deferring the increment of the count during
* bootstrap (see early_kmem_cache_node_alloc).
*/
if (likely(n)) {
atomic_long_inc(&n->nr_slabs);
atomic_long_add(objects, &n->total_objects);
}
}
static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
{
struct kmem_cache_node *n = get_node(s, node);
atomic_long_dec(&n->nr_slabs);
atomic_long_sub(objects, &n->total_objects);
}
/* Object debug checks for alloc/free paths */
static void setup_object_debug(struct kmem_cache *s, void *object)
{
if (!kmem_cache_debug_flags(s, SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON))
return;
init_object(s, object, SLUB_RED_INACTIVE);
init_tracking(s, object);
}
static
void setup_slab_debug(struct kmem_cache *s, struct slab *slab, void *addr)
{
if (!kmem_cache_debug_flags(s, SLAB_POISON))
return;
metadata_access_enable();
memset(kasan_reset_tag(addr), POISON_INUSE, slab_size(slab));
metadata_access_disable();
}
static inline int alloc_consistency_checks(struct kmem_cache *s,
struct slab *slab, void *object)
{
if (!check_slab(s, slab))
return 0;
if (!check_valid_pointer(s, slab, object)) {
object_err(s, slab, object, "Freelist Pointer check fails");
return 0;
}
if (!check_object(s, slab, object, SLUB_RED_INACTIVE))
return 0;
return 1;
}
static noinline bool alloc_debug_processing(struct kmem_cache *s,
struct slab *slab, void *object, int orig_size)
{
if (s->flags & SLAB_CONSISTENCY_CHECKS) {
if (!alloc_consistency_checks(s, slab, object))
goto bad;
}
/* Success. Perform special debug activities for allocs */
trace(s, slab, object, 1);
set_orig_size(s, object, orig_size);
init_object(s, object, SLUB_RED_ACTIVE);
return true;
bad:
if (folio_test_slab(slab_folio(slab))) {
/*
* If this is a slab page then lets do the best we can
* to avoid issues in the future. Marking all objects
* as used avoids touching the remaining objects.
*/
slab_fix(s, "Marking all objects used");
slab->inuse = slab->objects;
slab->freelist = NULL;
}
return false;
}
static inline int free_consistency_checks(struct kmem_cache *s,
struct slab *slab, void *object, unsigned long addr)
{
if (!check_valid_pointer(s, slab, object)) {
slab_err(s, slab, "Invalid object pointer 0x%p", object);
return 0;
}
if (on_freelist(s, slab, object)) {
object_err(s, slab, object, "Object already free");
return 0;
}
if (!check_object(s, slab, object, SLUB_RED_ACTIVE))
return 0;
if (unlikely(s != slab->slab_cache)) {
if (!folio_test_slab(slab_folio(slab))) {
slab_err(s, slab, "Attempt to free object(0x%p) outside of slab",
object);
} else if (!slab->slab_cache) {
pr_err("SLUB <none>: no slab for object 0x%p.\n",
object);
dump_stack();
} else
object_err(s, slab, object,
"page slab pointer corrupt.");
return 0;
}
return 1;
}
/*
* Parse a block of slub_debug options. Blocks are delimited by ';'
*
* @str: start of block
* @flags: returns parsed flags, or DEBUG_DEFAULT_FLAGS if none specified
* @slabs: return start of list of slabs, or NULL when there's no list
* @init: assume this is initial parsing and not per-kmem-create parsing
*
* returns the start of next block if there's any, or NULL
*/
static char *
parse_slub_debug_flags(char *str, slab_flags_t *flags, char **slabs, bool init)
{
bool higher_order_disable = false;
/* Skip any completely empty blocks */
while (*str && *str == ';')
str++;
if (*str == ',') {
/*
* No options but restriction on slabs. This means full
* debugging for slabs matching a pattern.
*/
*flags = DEBUG_DEFAULT_FLAGS;
goto check_slabs;
}
*flags = 0;
/* Determine which debug features should be switched on */
for (; *str && *str != ',' && *str != ';'; str++) {
switch (tolower(*str)) {
case '-':
*flags = 0;
break;
case 'f':
*flags |= SLAB_CONSISTENCY_CHECKS;
break;
case 'z':
*flags |= SLAB_RED_ZONE;
break;
case 'p':
*flags |= SLAB_POISON;
break;
case 'u':
*flags |= SLAB_STORE_USER;
break;
case 't':
*flags |= SLAB_TRACE;
break;
case 'a':
*flags |= SLAB_FAILSLAB;
break;
case 'o':
/*
* Avoid enabling debugging on caches if its minimum
* order would increase as a result.
*/
higher_order_disable = true;
break;
default:
if (init)
pr_err("slub_debug option '%c' unknown. skipped\n", *str);
}
}
check_slabs:
if (*str == ',')
*slabs = ++str;
else
*slabs = NULL;
/* Skip over the slab list */
while (*str && *str != ';')
str++;
/* Skip any completely empty blocks */
while (*str && *str == ';')
str++;
if (init && higher_order_disable)
disable_higher_order_debug = 1;
if (*str)
return str;
else
return NULL;
}
static int __init setup_slub_debug(char *str)
{
slab_flags_t flags;
slab_flags_t global_flags;
char *saved_str;
char *slab_list;
bool global_slub_debug_changed = false;
bool slab_list_specified = false;
global_flags = DEBUG_DEFAULT_FLAGS;
if (*str++ != '=' || !*str)
/*
* No options specified. Switch on full debugging.
*/
goto out;
saved_str = str;
while (str) {
str = parse_slub_debug_flags(str, &flags, &slab_list, true);
if (!slab_list) {
global_flags = flags;
global_slub_debug_changed = true;
} else {
slab_list_specified = true;
if (flags & SLAB_STORE_USER)
stack_depot_request_early_init();
}
}
/*
* For backwards compatibility, a single list of flags with list of
* slabs means debugging is only changed for those slabs, so the global
* slub_debug should be unchanged (0 or DEBUG_DEFAULT_FLAGS, depending
* on CONFIG_SLUB_DEBUG_ON). We can extended that to multiple lists as
* long as there is no option specifying flags without a slab list.
*/
if (slab_list_specified) {
if (!global_slub_debug_changed)
global_flags = slub_debug;
slub_debug_string = saved_str;
}
out:
slub_debug = global_flags;
if (slub_debug & SLAB_STORE_USER)
stack_depot_request_early_init();
if (slub_debug != 0 || slub_debug_string)
static_branch_enable(&slub_debug_enabled);
else
static_branch_disable(&slub_debug_enabled);
if ((static_branch_unlikely(&init_on_alloc) ||
static_branch_unlikely(&init_on_free)) &&
(slub_debug & SLAB_POISON))
pr_info("mem auto-init: SLAB_POISON will take precedence over init_on_alloc/init_on_free\n");
return 1;
}
__setup("slub_debug", setup_slub_debug);
/*
* kmem_cache_flags - apply debugging options to the cache
* @object_size: the size of an object without meta data
* @flags: flags to set
* @name: name of the cache
*
* Debug option(s) are applied to @flags. In addition to the debug
* option(s), if a slab name (or multiple) is specified i.e.
* slub_debug=<Debug-Options>,<slab name1>,<slab name2> ...
* then only the select slabs will receive the debug option(s).
*/
slab_flags_t kmem_cache_flags(unsigned int object_size,
slab_flags_t flags, const char *name)
{
char *iter;
size_t len;
char *next_block;
slab_flags_t block_flags;
slab_flags_t slub_debug_local = slub_debug;
if (flags & SLAB_NO_USER_FLAGS)
return flags;
/*
* If the slab cache is for debugging (e.g. kmemleak) then
* don't store user (stack trace) information by default,
* but let the user enable it via the command line below.
*/
if (flags & SLAB_NOLEAKTRACE)
slub_debug_local &= ~SLAB_STORE_USER;
len = strlen(name);
next_block = slub_debug_string;
/* Go through all blocks of debug options, see if any matches our slab's name */
while (next_block) {
next_block = parse_slub_debug_flags(next_block, &block_flags, &iter, false);
if (!iter)
continue;
/* Found a block that has a slab list, search it */
while (*iter) {
char *end, *glob;
size_t cmplen;
end = strchrnul(iter, ',');
if (next_block && next_block < end)
end = next_block - 1;
glob = strnchr(iter, end - iter, '*');
if (glob)
cmplen = glob - iter;
else
cmplen = max_t(size_t, len, (end - iter));
if (!strncmp(name, iter, cmplen)) {
flags |= block_flags;
return flags;
}
if (!*end || *end == ';')
break;
iter = end + 1;
}
}
return flags | slub_debug_local;
}
#else /* !CONFIG_SLUB_DEBUG */
static inline void setup_object_debug(struct kmem_cache *s, void *object) {}
static inline
void setup_slab_debug(struct kmem_cache *s, struct slab *slab, void *addr) {}
static inline bool alloc_debug_processing(struct kmem_cache *s,
struct slab *slab, void *object, int orig_size) { return true; }
static inline bool free_debug_processing(struct kmem_cache *s,
struct slab *slab, void *head, void *tail, int *bulk_cnt,
unsigned long addr, depot_stack_handle_t handle) { return true; }
static inline void slab_pad_check(struct kmem_cache *s, struct slab *slab) {}
static inline int check_object(struct kmem_cache *s, struct slab *slab,
void *object, u8 val) { return 1; }
static inline depot_stack_handle_t set_track_prepare(void) { return 0; }
static inline void set_track(struct kmem_cache *s, void *object,
enum track_item alloc, unsigned long addr) {}
static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n,
struct slab *slab) {}
static inline void remove_full(struct kmem_cache *s, struct kmem_cache_node *n,
struct slab *slab) {}
slab_flags_t kmem_cache_flags(unsigned int object_size,
slab_flags_t flags, const char *name)
{
return flags;
}
#define slub_debug 0
#define disable_higher_order_debug 0
static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
{ return 0; }
static inline void inc_slabs_node(struct kmem_cache *s, int node,
int objects) {}
static inline void dec_slabs_node(struct kmem_cache *s, int node,
int objects) {}
#ifndef CONFIG_SLUB_TINY
static bool freelist_corrupted(struct kmem_cache *s, struct slab *slab,
void **freelist, void *nextfree)
{
return false;
}
#endif
#endif /* CONFIG_SLUB_DEBUG */
/*
* Hooks for other subsystems that check memory allocations. In a typical
* production configuration these hooks all should produce no code at all.
*/
static __always_inline bool slab_free_hook(struct kmem_cache *s,
void *x, bool init)
{
kmemleak_free_recursive(x, s->flags);
kmsan_slab_free(s, x);
debug_check_no_locks_freed(x, s->object_size);
if (!(s->flags & SLAB_DEBUG_OBJECTS))
debug_check_no_obj_freed(x, s->object_size);
/* Use KCSAN to help debug racy use-after-free. */
if (!(s->flags & SLAB_TYPESAFE_BY_RCU))
__kcsan_check_access(x, s->object_size,
KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ASSERT);
/*
* As memory initialization might be integrated into KASAN,
* kasan_slab_free and initialization memset's must be
* kept together to avoid discrepancies in behavior.
*
* The initialization memset's clear the object and the metadata,
* but don't touch the SLAB redzone.
*/
if (init) {
int rsize;
if (!kasan_has_integrated_init())
memset(kasan_reset_tag(x), 0, s->object_size);
rsize = (s->flags & SLAB_RED_ZONE) ? s->red_left_pad : 0;
memset((char *)kasan_reset_tag(x) + s->inuse, 0,
s->size - s->inuse - rsize);
}
/* KASAN might put x into memory quarantine, delaying its reuse. */
return kasan_slab_free(s, x, init);
}
static inline bool slab_free_freelist_hook(struct kmem_cache *s,
void **head, void **tail,
int *cnt)
{
void *object;
void *next = *head;
void *old_tail = *tail ? *tail : *head;
if (is_kfence_address(next)) {
slab_free_hook(s, next, false);
return true;
}
/* Head and tail of the reconstructed freelist */
*head = NULL;
*tail = NULL;
do {
object = next;
next = get_freepointer(s, object);
/* If object's reuse doesn't have to be delayed */
if (!slab_free_hook(s, object, slab_want_init_on_free(s))) {
/* Move object to the new freelist */
set_freepointer(s, object, *head);
*head = object;
if (!*tail)
*tail = object;
} else {
/*
* Adjust the reconstructed freelist depth
* accordingly if object's reuse is delayed.
*/
--(*cnt);
}
} while (object != old_tail);
if (*head == *tail)
*tail = NULL;
return *head != NULL;
}
static void *setup_object(struct kmem_cache *s, void *object)
{
setup_object_debug(s, object);
object = kasan_init_slab_obj(s, object);
if (unlikely(s->ctor)) {
kasan_unpoison_object_data(s, object);
s->ctor(object);
kasan_poison_object_data(s, object);
}
return object;
}
/*
* Slab allocation and freeing
*/
static inline struct slab *alloc_slab_page(gfp_t flags, int node,
struct kmem_cache_order_objects oo)
{
struct folio *folio;
struct slab *slab;
unsigned int order = oo_order(oo);
if (node == NUMA_NO_NODE)
folio = (struct folio *)alloc_pages(flags, order);
else
folio = (struct folio *)__alloc_pages_node(node, flags, order);
if (!folio)
return NULL;
slab = folio_slab(folio);
__folio_set_slab(folio);
/* Make the flag visible before any changes to folio->mapping */
smp_wmb();
if (folio_is_pfmemalloc(folio))
slab_set_pfmemalloc(slab);
return slab;
}
#ifdef CONFIG_SLAB_FREELIST_RANDOM
/* Pre-initialize the random sequence cache */
static int init_cache_random_seq(struct kmem_cache *s)
{
unsigned int count = oo_objects(s->oo);
int err;
/* Bailout if already initialised */
if (s->random_seq)
return 0;
err = cache_random_seq_create(s, count, GFP_KERNEL);
if (err) {
pr_err("SLUB: Unable to initialize free list for %s\n",
s->name);
return err;
}
/* Transform to an offset on the set of pages */
if (s->random_seq) {
unsigned int i;
for (i = 0; i < count; i++)
s->random_seq[i] *= s->size;
}
return 0;
}
/* Initialize each random sequence freelist per cache */
static void __init init_freelist_randomization(void)
{
struct kmem_cache *s;
mutex_lock(&slab_mutex);
list_for_each_entry(s, &slab_caches, list)
init_cache_random_seq(s);
mutex_unlock(&slab_mutex);
}
/* Get the next entry on the pre-computed freelist randomized */
static void *next_freelist_entry(struct kmem_cache *s, struct slab *slab,
unsigned long *pos, void *start,
unsigned long page_limit,
unsigned long freelist_count)
{
unsigned int idx;
/*
* If the target page allocation failed, the number of objects on the
* page might be smaller than the usual size defined by the cache.
*/
do {
idx = s->random_seq[*pos];
*pos += 1;
if (*pos >= freelist_count)
*pos = 0;
} while (unlikely(idx >= page_limit));
return (char *)start + idx;
}
/* Shuffle the single linked freelist based on a random pre-computed sequence */
static bool shuffle_freelist(struct kmem_cache *s, struct slab *slab)
{
void *start;
void *cur;
void *next;
unsigned long idx, pos, page_limit, freelist_count;
if (slab->objects < 2 || !s->random_seq)
return false;
freelist_count = oo_objects(s->oo);
pos = get_random_u32_below(freelist_count);
page_limit = slab->objects * s->size;
start = fixup_red_left(s, slab_address(slab));
/* First entry is used as the base of the freelist */
cur = next_freelist_entry(s, slab, &pos, start, page_limit,
freelist_count);
cur = setup_object(s, cur);
slab->freelist = cur;
for (idx = 1; idx < slab->objects; idx++) {
next = next_freelist_entry(s, slab, &pos, start, page_limit,
freelist_count);
next = setup_object(s, next);
set_freepointer(s, cur, next);
cur = next;
}
set_freepointer(s, cur, NULL);
return true;
}
#else
static inline int init_cache_random_seq(struct kmem_cache *s)
{
return 0;
}
static inline void init_freelist_randomization(void) { }
static inline bool shuffle_freelist(struct kmem_cache *s, struct slab *slab)
{
return false;
}
#endif /* CONFIG_SLAB_FREELIST_RANDOM */
static struct slab *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
{
struct slab *slab;
struct kmem_cache_order_objects oo = s->oo;
gfp_t alloc_gfp;
void *start, *p, *next;
int idx;
bool shuffle;
flags &= gfp_allowed_mask;
flags |= s->allocflags;
/*
* Let the initial higher-order allocation fail under memory pressure
* so we fall-back to the minimum order allocation.
*/
alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
if ((alloc_gfp & __GFP_DIRECT_RECLAIM) && oo_order(oo) > oo_order(s->min))
alloc_gfp = (alloc_gfp | __GFP_NOMEMALLOC) & ~__GFP_RECLAIM;
slab = alloc_slab_page(alloc_gfp, node, oo);
if (unlikely(!slab)) {
oo = s->min;
alloc_gfp = flags;
/*
* Allocation may have failed due to fragmentation.
* Try a lower order alloc if possible
*/
slab = alloc_slab_page(alloc_gfp, node, oo);
if (unlikely(!slab))
return NULL;
stat(s, ORDER_FALLBACK);
}
slab->objects = oo_objects(oo);
slab->inuse = 0;
slab->frozen = 0;
account_slab(slab, oo_order(oo), s, flags);
slab->slab_cache = s;
kasan_poison_slab(slab);
start = slab_address(slab);
setup_slab_debug(s, slab, start);
shuffle = shuffle_freelist(s, slab);
if (!shuffle) {
start = fixup_red_left(s, start);
start = setup_object(s, start);
slab->freelist = start;
for (idx = 0, p = start; idx < slab->objects - 1; idx++) {
next = p + s->size;
next = setup_object(s, next);
set_freepointer(s, p, next);
p = next;
}
set_freepointer(s, p, NULL);
}
return slab;
}
static struct slab *new_slab(struct kmem_cache *s, gfp_t flags, int node)
{
if (unlikely(flags & GFP_SLAB_BUG_MASK))
flags = kmalloc_fix_flags(flags);
WARN_ON_ONCE(s->ctor && (flags & __GFP_ZERO));
return allocate_slab(s,
flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
}
static void __free_slab(struct kmem_cache *s, struct slab *slab)
{
struct folio *folio = slab_folio(slab);
int order = folio_order(folio);
int pages = 1 << order;
__slab_clear_pfmemalloc(slab);
folio->mapping = NULL;
/* Make the mapping reset visible before clearing the flag */
smp_wmb();
__folio_clear_slab(folio);
mm_account_reclaimed_pages(pages);
unaccount_slab(slab, order, s);
__free_pages(&folio->page, order);
}
static void rcu_free_slab(struct rcu_head *h)
{
struct slab *slab = container_of(h, struct slab, rcu_head);
__free_slab(slab->slab_cache, slab);
}
static void free_slab(struct kmem_cache *s, struct slab *slab)
{
if (kmem_cache_debug_flags(s, SLAB_CONSISTENCY_CHECKS)) {
void *p;
slab_pad_check(s, slab);
for_each_object(p, s, slab_address(slab), slab->objects)
check_object(s, slab, p, SLUB_RED_INACTIVE);
}
if (unlikely(s->flags & SLAB_TYPESAFE_BY_RCU))
call_rcu(&slab->rcu_head, rcu_free_slab);
else
__free_slab(s, slab);
}
static void discard_slab(struct kmem_cache *s, struct slab *slab)
{
dec_slabs_node(s, slab_nid(slab), slab->objects);
free_slab(s, slab);
}
/*
* Management of partially allocated slabs.
*/
static inline void
__add_partial(struct kmem_cache_node *n, struct slab *slab, int tail)
{
n->nr_partial++;
if (tail == DEACTIVATE_TO_TAIL)
list_add_tail(&slab->slab_list, &n->partial);
else
list_add(&slab->slab_list, &n->partial);
}
static inline void add_partial(struct kmem_cache_node *n,
struct slab *slab, int tail)
{
lockdep_assert_held(&n->list_lock);
__add_partial(n, slab, tail);
}
static inline void remove_partial(struct kmem_cache_node *n,
struct slab *slab)
{
lockdep_assert_held(&n->list_lock);
list_del(&slab->slab_list);
n->nr_partial--;
}
/*
* Called only for kmem_cache_debug() caches instead of acquire_slab(), with a
* slab from the n->partial list. Remove only a single object from the slab, do
* the alloc_debug_processing() checks and leave the slab on the list, or move
* it to full list if it was the last free object.
*/
static void *alloc_single_from_partial(struct kmem_cache *s,
struct kmem_cache_node *n, struct slab *slab, int orig_size)
{
void *object;
lockdep_assert_held(&n->list_lock);
object = slab->freelist;
slab->freelist = get_freepointer(s, object);
slab->inuse++;
if (!alloc_debug_processing(s, slab, object, orig_size)) {
remove_partial(n, slab);
return NULL;
}
if (slab->inuse == slab->objects) {
remove_partial(n, slab);
add_full(s, n, slab);
}
return object;
}
/*
* Called only for kmem_cache_debug() caches to allocate from a freshly
* allocated slab. Allocate a single object instead of whole freelist
* and put the slab to the partial (or full) list.
*/
static void *alloc_single_from_new_slab(struct kmem_cache *s,
struct slab *slab, int orig_size)
{
int nid = slab_nid(slab);
struct kmem_cache_node *n = get_node(s, nid);
unsigned long flags;
void *object;
object = slab->freelist;
slab->freelist = get_freepointer(s, object);
slab->inuse = 1;
if (!alloc_debug_processing(s, slab, object, orig_size))
/*
* It's not really expected that this would fail on a
* freshly allocated slab, but a concurrent memory
* corruption in theory could cause that.
*/
return NULL;
spin_lock_irqsave(&n->list_lock, flags);
if (slab->inuse == slab->objects)
add_full(s, n, slab);
else
add_partial(n, slab, DEACTIVATE_TO_HEAD);
inc_slabs_node(s, nid, slab->objects);
spin_unlock_irqrestore(&n->list_lock, flags);
return object;
}
/*
* Remove slab from the partial list, freeze it and
* return the pointer to the freelist.
*
* Returns a list of objects or NULL if it fails.
*/
static inline void *acquire_slab(struct kmem_cache *s,
struct kmem_cache_node *n, struct slab *slab,
int mode)
{
void *freelist;
unsigned long counters;
struct slab new;
lockdep_assert_held(&n->list_lock);
/*
* Zap the freelist and set the frozen bit.
* The old freelist is the list of objects for the
* per cpu allocation list.
*/
freelist = slab->freelist;
counters = slab->counters;
new.counters = counters;
if (mode) {
new.inuse = slab->objects;
new.freelist = NULL;
} else {
new.freelist = freelist;
}
VM_BUG_ON(new.frozen);
new.frozen = 1;
if (!__slab_update_freelist(s, slab,
freelist, counters,
new.freelist, new.counters,
"acquire_slab"))
return NULL;
remove_partial(n, slab);
WARN_ON(!freelist);
return freelist;
}
#ifdef CONFIG_SLUB_CPU_PARTIAL
static void put_cpu_partial(struct kmem_cache *s, struct slab *slab, int drain);
#else
static inline void put_cpu_partial(struct kmem_cache *s, struct slab *slab,
int drain) { }
#endif
static inline bool pfmemalloc_match(struct slab *slab, gfp_t gfpflags);
/*
* Try to allocate a partial slab from a specific node.
*/
static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
struct partial_context *pc)
{
struct slab *slab, *slab2;
void *object = NULL;
unsigned long flags;
unsigned int partial_slabs = 0;
/*
* Racy check. If we mistakenly see no partial slabs then we
* just allocate an empty slab. If we mistakenly try to get a
* partial slab and there is none available then get_partial()
* will return NULL.
*/
if (!n || !n->nr_partial)
return NULL;
spin_lock_irqsave(&n->list_lock, flags);
list_for_each_entry_safe(slab, slab2, &n->partial, slab_list) {
void *t;
if (!pfmemalloc_match(slab, pc->flags))
continue;
if (IS_ENABLED(CONFIG_SLUB_TINY) || kmem_cache_debug(s)) {
object = alloc_single_from_partial(s, n, slab,
pc->orig_size);
if (object)
break;
continue;
}
t = acquire_slab(s, n, slab, object == NULL);
if (!t)
break;
if (!object) {
*pc->slab = slab;
stat(s, ALLOC_FROM_PARTIAL);
object = t;
} else {
put_cpu_partial(s, slab, 0);
stat(s, CPU_PARTIAL_NODE);
partial_slabs++;
}
#ifdef CONFIG_SLUB_CPU_PARTIAL
if (!kmem_cache_has_cpu_partial(s)
|| partial_slabs > s->cpu_partial_slabs / 2)
break;
#else
break;
#endif
}
spin_unlock_irqrestore(&n->list_lock, flags);
return object;
}
/*
* Get a slab from somewhere. Search in increasing NUMA distances.
*/
static void *get_any_partial(struct kmem_cache *s, struct partial_context *pc)
{
#ifdef CONFIG_NUMA
struct zonelist *zonelist;
struct zoneref *z;
struct zone *zone;
enum zone_type highest_zoneidx = gfp_zone(pc->flags);
void *object;
unsigned int cpuset_mems_cookie;
/*
* The defrag ratio allows a configuration of the tradeoffs between
* inter node defragmentation and node local allocations. A lower
* defrag_ratio increases the tendency to do local allocations
* instead of attempting to obtain partial slabs from other nodes.
*
* If the defrag_ratio is set to 0 then kmalloc() always
* returns node local objects. If the ratio is higher then kmalloc()
* may return off node objects because partial slabs are obtained
* from other nodes and filled up.
*
* If /sys/kernel/slab/xx/remote_node_defrag_ratio is set to 100
* (which makes defrag_ratio = 1000) then every (well almost)
* allocation will first attempt to defrag slab caches on other nodes.
* This means scanning over all nodes to look for partial slabs which
* may be expensive if we do it every time we are trying to find a slab
* with available objects.
*/
if (!s->remote_node_defrag_ratio ||
get_cycles() % 1024 > s->remote_node_defrag_ratio)
return NULL;
do {
cpuset_mems_cookie = read_mems_allowed_begin();
zonelist = node_zonelist(mempolicy_slab_node(), pc->flags);
for_each_zone_zonelist(zone, z, zonelist, highest_zoneidx) {
struct kmem_cache_node *n;
n = get_node(s, zone_to_nid(zone));
if (n && cpuset_zone_allowed(zone, pc->flags) &&
n->nr_partial > s->min_partial) {
object = get_partial_node(s, n, pc);
if (object) {
/*
* Don't check read_mems_allowed_retry()
* here - if mems_allowed was updated in
* parallel, that was a harmless race
* between allocation and the cpuset
* update
*/
return object;
}
}
}
} while (read_mems_allowed_retry(cpuset_mems_cookie));
#endif /* CONFIG_NUMA */
return NULL;
}
/*
* Get a partial slab, lock it and return it.
*/
static void *get_partial(struct kmem_cache *s, int node, struct partial_context *pc)
{
void *object;
int searchnode = node;
if (node == NUMA_NO_NODE)
searchnode = numa_mem_id();
object = get_partial_node(s, get_node(s, searchnode), pc);
if (object || node != NUMA_NO_NODE)
return object;
return get_any_partial(s, pc);
}
#ifndef CONFIG_SLUB_TINY
#ifdef CONFIG_PREEMPTION
/*
* Calculate the next globally unique transaction for disambiguation
* during cmpxchg. The transactions start with the cpu number and are then
* incremented by CONFIG_NR_CPUS.
*/
#define TID_STEP roundup_pow_of_two(CONFIG_NR_CPUS)
#else
/*
* No preemption supported therefore also no need to check for
* different cpus.
*/
#define TID_STEP 1
#endif /* CONFIG_PREEMPTION */
static inline unsigned long next_tid(unsigned long tid)
{
return tid + TID_STEP;
}
#ifdef SLUB_DEBUG_CMPXCHG
static inline unsigned int tid_to_cpu(unsigned long tid)
{
return tid % TID_STEP;
}
static inline unsigned long tid_to_event(unsigned long tid)
{
return tid / TID_STEP;
}
#endif
static inline unsigned int init_tid(int cpu)
{
return cpu;
}
static inline void note_cmpxchg_failure(const char *n,
const struct kmem_cache *s, unsigned long tid)
{
#ifdef SLUB_DEBUG_CMPXCHG
unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid);
pr_info("%s %s: cmpxchg redo ", n, s->name);
#ifdef CONFIG_PREEMPTION
if (tid_to_cpu(tid) != tid_to_cpu(actual_tid))
pr_warn("due to cpu change %d -> %d\n",
tid_to_cpu(tid), tid_to_cpu(actual_tid));
else
#endif
if (tid_to_event(tid) != tid_to_event(actual_tid))
pr_warn("due to cpu running other code. Event %ld->%ld\n",
tid_to_event(tid), tid_to_event(actual_tid));
else
pr_warn("for unknown reason: actual=%lx was=%lx target=%lx\n",
actual_tid, tid, next_tid(tid));
#endif
stat(s, CMPXCHG_DOUBLE_CPU_FAIL);
}
static void init_kmem_cache_cpus(struct kmem_cache *s)
{
int cpu;
struct kmem_cache_cpu *c;
for_each_possible_cpu(cpu) {
c = per_cpu_ptr(s->cpu_slab, cpu);
local_lock_init(&c->lock);
c->tid = init_tid(cpu);
}
}
/*
* Finishes removing the cpu slab. Merges cpu's freelist with slab's freelist,
* unfreezes the slabs and puts it on the proper list.
* Assumes the slab has been already safely taken away from kmem_cache_cpu
* by the caller.
*/
static void deactivate_slab(struct kmem_cache *s, struct slab *slab,
void *freelist)
{
enum slab_modes { M_NONE, M_PARTIAL, M_FREE, M_FULL_NOLIST };
struct kmem_cache_node *n = get_node(s, slab_nid(slab));
int free_delta = 0;
enum slab_modes mode = M_NONE;
void *nextfree, *freelist_iter, *freelist_tail;
int tail = DEACTIVATE_TO_HEAD;
unsigned long flags = 0;
struct slab new;
struct slab old;
if (slab->freelist) {
stat(s, DEACTIVATE_REMOTE_FREES);
tail = DEACTIVATE_TO_TAIL;
}
/*
* Stage one: Count the objects on cpu's freelist as free_delta and
* remember the last object in freelist_tail for later splicing.
*/
freelist_tail = NULL;
freelist_iter = freelist;
while (freelist_iter) {
nextfree = get_freepointer(s, freelist_iter);
/*
* If 'nextfree' is invalid, it is possible that the object at
* 'freelist_iter' is already corrupted. So isolate all objects
* starting at 'freelist_iter' by skipping them.
*/
if (freelist_corrupted(s, slab, &freelist_iter, nextfree))
break;
freelist_tail = freelist_iter;
free_delta++;
freelist_iter = nextfree;
}
/*
* Stage two: Unfreeze the slab while splicing the per-cpu
* freelist to the head of slab's freelist.
*
* Ensure that the slab is unfrozen while the list presence
* reflects the actual number of objects during unfreeze.
*
* We first perform cmpxchg holding lock and insert to list
* when it succeed. If there is mismatch then the slab is not
* unfrozen and number of objects in the slab may have changed.
* Then release lock and retry cmpxchg again.
*/
redo:
old.freelist = READ_ONCE(slab->freelist);
old.counters = READ_ONCE(slab->counters);
VM_BUG_ON(!old.frozen);
/* Determine target state of the slab */
new.counters = old.counters;
if (freelist_tail) {
new.inuse -= free_delta;
set_freepointer(s, freelist_tail, old.freelist);
new.freelist = freelist;
} else
new.freelist = old.freelist;
new.frozen = 0;
if (!new.inuse && n->nr_partial >= s->min_partial) {
mode = M_FREE;
} else if (new.freelist) {
mode = M_PARTIAL;
/*
* Taking the spinlock removes the possibility that
* acquire_slab() will see a slab that is frozen
*/
spin_lock_irqsave(&n->list_lock, flags);
} else {
mode = M_FULL_NOLIST;
}
if (!slab_update_freelist(s, slab,
old.freelist, old.counters,
new.freelist, new.counters,
"unfreezing slab")) {
if (mode == M_PARTIAL)
spin_unlock_irqrestore(&n->list_lock, flags);
goto redo;
}
if (mode == M_PARTIAL) {
add_partial(n, slab, tail);
spin_unlock_irqrestore(&n->list_lock, flags);
stat(s, tail);
} else if (mode == M_FREE) {
stat(s, DEACTIVATE_EMPTY);
discard_slab(s, slab);
stat(s, FREE_SLAB);
} else if (mode == M_FULL_NOLIST) {
stat(s, DEACTIVATE_FULL);
}
}
#ifdef CONFIG_SLUB_CPU_PARTIAL
static void __unfreeze_partials(struct kmem_cache *s, struct slab *partial_slab)
{
struct kmem_cache_node *n = NULL, *n2 = NULL;
struct slab *slab, *slab_to_discard = NULL;
unsigned long flags = 0;
while (partial_slab) {
struct slab new;
struct slab old;
slab = partial_slab;
partial_slab = slab->next;
n2 = get_node(s, slab_nid(slab));
if (n != n2) {
if (n)
spin_unlock_irqrestore(&n->list_lock, flags);
n = n2;
spin_lock_irqsave(&n->list_lock, flags);
}
do {
old.freelist = slab->freelist;
old.counters = slab->counters;
VM_BUG_ON(!old.frozen);
new.counters = old.counters;
new.freelist = old.freelist;
new.frozen = 0;
} while (!__slab_update_freelist(s, slab,
old.freelist, old.counters,
new.freelist, new.counters,
"unfreezing slab"));
if (unlikely(!new.inuse && n->nr_partial >= s->min_partial)) {
slab->next = slab_to_discard;
slab_to_discard = slab;
} else {
add_partial(n, slab, DEACTIVATE_TO_TAIL);
stat(s, FREE_ADD_PARTIAL);
}
}
if (n)
spin_unlock_irqrestore(&n->list_lock, flags);
while (slab_to_discard) {
slab = slab_to_discard;
slab_to_discard = slab_to_discard->next;
stat(s, DEACTIVATE_EMPTY);
discard_slab(s, slab);
stat(s, FREE_SLAB);
}
}
/*
* Unfreeze all the cpu partial slabs.
*/
static void unfreeze_partials(struct kmem_cache *s)
{
struct slab *partial_slab;
unsigned long flags;
local_lock_irqsave(&s->cpu_slab->lock, flags);
partial_slab = this_cpu_read(s->cpu_slab->partial);
this_cpu_write(s->cpu_slab->partial, NULL);
local_unlock_irqrestore(&s->cpu_slab->lock, flags);
if (partial_slab)
__unfreeze_partials(s, partial_slab);
}
static void unfreeze_partials_cpu(struct kmem_cache *s,
struct kmem_cache_cpu *c)
{
struct slab *partial_slab;
partial_slab = slub_percpu_partial(c);
c->partial = NULL;
if (partial_slab)
__unfreeze_partials(s, partial_slab);
}
/*
* Put a slab that was just frozen (in __slab_free|get_partial_node) into a
* partial slab slot if available.
*
* If we did not find a slot then simply move all the partials to the
* per node partial list.
*/
static void put_cpu_partial(struct kmem_cache *s, struct slab *slab, int drain)
{
struct slab *oldslab;
struct slab *slab_to_unfreeze = NULL;
unsigned long flags;
int slabs = 0;
local_lock_irqsave(&s->cpu_slab->lock, flags);
oldslab = this_cpu_read(s->cpu_slab->partial);
if (oldslab) {
if (drain && oldslab->slabs >= s->cpu_partial_slabs) {
/*
* Partial array is full. Move the existing set to the
* per node partial list. Postpone the actual unfreezing
* outside of the critical section.
*/
slab_to_unfreeze = oldslab;
oldslab = NULL;
} else {
slabs = oldslab->slabs;
}
}
slabs++;
slab->slabs = slabs;
slab->next = oldslab;
this_cpu_write(s->cpu_slab->partial, slab);
local_unlock_irqrestore(&s->cpu_slab->lock, flags);
if (slab_to_unfreeze) {
__unfreeze_partials(s, slab_to_unfreeze);
stat(s, CPU_PARTIAL_DRAIN);
}
}
#else /* CONFIG_SLUB_CPU_PARTIAL */
static inline void unfreeze_partials(struct kmem_cache *s) { }
static inline void unfreeze_partials_cpu(struct kmem_cache *s,
struct kmem_cache_cpu *c) { }
#endif /* CONFIG_SLUB_CPU_PARTIAL */
static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
{
unsigned long flags;
struct slab *slab;
void *freelist;
local_lock_irqsave(&s->cpu_slab->lock, flags);
slab = c->slab;
freelist = c->freelist;
c->slab = NULL;
c->freelist = NULL;
c->tid = next_tid(c->tid);
local_unlock_irqrestore(&s->cpu_slab->lock, flags);
if (slab) {
deactivate_slab(s, slab, freelist);
stat(s, CPUSLAB_FLUSH);
}
}
static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
{
struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
void *freelist = c->freelist;
struct slab *slab = c->slab;
c->slab = NULL;
c->freelist = NULL;
c->tid = next_tid(c->tid);
if (slab) {
deactivate_slab(s, slab, freelist);
stat(s, CPUSLAB_FLUSH);
}
unfreeze_partials_cpu(s, c);
}
struct slub_flush_work {
struct work_struct work;
struct kmem_cache *s;
bool skip;
};
/*
* Flush cpu slab.
*
* Called from CPU work handler with migration disabled.
*/
static void flush_cpu_slab(struct work_struct *w)
{
struct kmem_cache *s;
struct kmem_cache_cpu *c;
struct slub_flush_work *sfw;
sfw = container_of(w, struct slub_flush_work, work);
s = sfw->s;
c = this_cpu_ptr(s->cpu_slab);
if (c->slab)
flush_slab(s, c);
unfreeze_partials(s);
}
static bool has_cpu_slab(int cpu, struct kmem_cache *s)
{
struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
return c->slab || slub_percpu_partial(c);
}
static DEFINE_MUTEX(flush_lock);
static DEFINE_PER_CPU(struct slub_flush_work, slub_flush);
static void flush_all_cpus_locked(struct kmem_cache *s)
{
struct slub_flush_work *sfw;
unsigned int cpu;
lockdep_assert_cpus_held();
mutex_lock(&flush_lock);
for_each_online_cpu(cpu) {
sfw = &per_cpu(slub_flush, cpu);
if (!has_cpu_slab(cpu, s)) {
sfw->skip = true;
continue;
}
INIT_WORK(&sfw->work, flush_cpu_slab);
sfw->skip = false;
sfw->s = s;
queue_work_on(cpu, flushwq, &sfw->work);
}
for_each_online_cpu(cpu) {
sfw = &per_cpu(slub_flush, cpu);
if (sfw->skip)
continue;
flush_work(&sfw->work);
}
mutex_unlock(&flush_lock);
}
static void flush_all(struct kmem_cache *s)
{
cpus_read_lock();
flush_all_cpus_locked(s);
cpus_read_unlock();
}
/*
* Use the cpu notifier to insure that the cpu slabs are flushed when
* necessary.
*/
static int slub_cpu_dead(unsigned int cpu)
{
struct kmem_cache *s;
mutex_lock(&slab_mutex);
list_for_each_entry(s, &slab_caches, list)
__flush_cpu_slab(s, cpu);
mutex_unlock(&slab_mutex);
return 0;
}
#else /* CONFIG_SLUB_TINY */
static inline void flush_all_cpus_locked(struct kmem_cache *s) { }
static inline void flush_all(struct kmem_cache *s) { }
static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu) { }
static inline int slub_cpu_dead(unsigned int cpu) { return 0; }
#endif /* CONFIG_SLUB_TINY */
/*
* Check if the objects in a per cpu structure fit numa
* locality expectations.
*/
static inline int node_match(struct slab *slab, int node)
{
#ifdef CONFIG_NUMA
if (node != NUMA_NO_NODE && slab_nid(slab) != node)
return 0;
#endif
return 1;
}
#ifdef CONFIG_SLUB_DEBUG
static int count_free(struct slab *slab)
{
return slab->objects - slab->inuse;
}
static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
{
return atomic_long_read(&n->total_objects);
}
/* Supports checking bulk free of a constructed freelist */
static inline bool free_debug_processing(struct kmem_cache *s,
struct slab *slab, void *head, void *tail, int *bulk_cnt,
unsigned long addr, depot_stack_handle_t handle)
{
bool checks_ok = false;
void *object = head;
int cnt = 0;
if (s->flags & SLAB_CONSISTENCY_CHECKS) {
if (!check_slab(s, slab))
goto out;
}
if (slab->inuse < *bulk_cnt) {
slab_err(s, slab, "Slab has %d allocated objects but %d are to be freed\n",
slab->inuse, *bulk_cnt);
goto out;
}
next_object:
if (++cnt > *bulk_cnt)
goto out_cnt;
if (s->flags & SLAB_CONSISTENCY_CHECKS) {
if (!free_consistency_checks(s, slab, object, addr))
goto out;
}
if (s->flags & SLAB_STORE_USER)
set_track_update(s, object, TRACK_FREE, addr, handle);
trace(s, slab, object, 0);
/* Freepointer not overwritten by init_object(), SLAB_POISON moved it */
init_object(s, object, SLUB_RED_INACTIVE);
/* Reached end of constructed freelist yet? */
if (object != tail) {
object = get_freepointer(s, object);
goto next_object;
}
checks_ok = true;
out_cnt:
if (cnt != *bulk_cnt) {
slab_err(s, slab, "Bulk free expected %d objects but found %d\n",
*bulk_cnt, cnt);
*bulk_cnt = cnt;
}
out:
if (!checks_ok)
slab_fix(s, "Object at 0x%p not freed", object);
return checks_ok;
}
#endif /* CONFIG_SLUB_DEBUG */
#if defined(CONFIG_SLUB_DEBUG) || defined(SLAB_SUPPORTS_SYSFS)
static unsigned long count_partial(struct kmem_cache_node *n,
int (*get_count)(struct slab *))
{
unsigned long flags;
unsigned long x = 0;
struct slab *slab;
spin_lock_irqsave(&n->list_lock, flags);
list_for_each_entry(slab, &n->partial, slab_list)
x += get_count(slab);
spin_unlock_irqrestore(&n->list_lock, flags);
return x;
}
#endif /* CONFIG_SLUB_DEBUG || SLAB_SUPPORTS_SYSFS */
#ifdef CONFIG_SLUB_DEBUG
static noinline void
slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
{
static DEFINE_RATELIMIT_STATE(slub_oom_rs, DEFAULT_RATELIMIT_INTERVAL,
DEFAULT_RATELIMIT_BURST);
int node;
struct kmem_cache_node *n;
if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slub_oom_rs))
return;
pr_warn("SLUB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n",
nid, gfpflags, &gfpflags);
pr_warn(" cache: %s, object size: %u, buffer size: %u, default order: %u, min order: %u\n",
s->name, s->object_size, s->size, oo_order(s->oo),
oo_order(s->min));
if (oo_order(s->min) > get_order(s->object_size))
pr_warn(" %s debugging increased min order, use slub_debug=O to disable.\n",
s->name);
for_each_kmem_cache_node(s, node, n) {
unsigned long nr_slabs;
unsigned long nr_objs;
unsigned long nr_free;
nr_free = count_partial(n, count_free);
nr_slabs = node_nr_slabs(n);
nr_objs = node_nr_objs(n);
pr_warn(" node %d: slabs: %ld, objs: %ld, free: %ld\n",
node, nr_slabs, nr_objs, nr_free);
}
}
#else /* CONFIG_SLUB_DEBUG */
static inline void
slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid) { }
#endif
static inline bool pfmemalloc_match(struct slab *slab, gfp_t gfpflags)
{
if (unlikely(slab_test_pfmemalloc(slab)))
return gfp_pfmemalloc_allowed(gfpflags);
return true;
}
#ifndef CONFIG_SLUB_TINY
static inline bool
__update_cpu_freelist_fast(struct kmem_cache *s,
void *freelist_old, void *freelist_new,
unsigned long tid)
{
freelist_aba_t old = { .freelist = freelist_old, .counter = tid };
freelist_aba_t new = { .freelist = freelist_new, .counter = next_tid(tid) };
return this_cpu_try_cmpxchg_freelist(s->cpu_slab->freelist_tid.full,
&old.full, new.full);
}
/*
* Check the slab->freelist and either transfer the freelist to the
* per cpu freelist or deactivate the slab.
*
* The slab is still frozen if the return value is not NULL.
*
* If this function returns NULL then the slab has been unfrozen.
*/
static inline void *get_freelist(struct kmem_cache *s, struct slab *slab)
{
struct slab new;
unsigned long counters;
void *freelist;
lockdep_assert_held(this_cpu_ptr(&s->cpu_slab->lock));
do {
freelist = slab->freelist;
counters = slab->counters;
new.counters = counters;
VM_BUG_ON(!new.frozen);
new.inuse = slab->objects;
new.frozen = freelist != NULL;
} while (!__slab_update_freelist(s, slab,
freelist, counters,
NULL, new.counters,
"get_freelist"));
return freelist;
}
/*
* Slow path. The lockless freelist is empty or we need to perform
* debugging duties.
*
* Processing is still very fast if new objects have been freed to the
* regular freelist. In that case we simply take over the regular freelist
* as the lockless freelist and zap the regular freelist.
*
* If that is not working then we fall back to the partial lists. We take the
* first element of the freelist as the object to allocate now and move the
* rest of the freelist to the lockless freelist.
*
* And if we were unable to get a new slab from the partial slab lists then
* we need to allocate a new slab. This is the slowest path since it involves
* a call to the page allocator and the setup of a new slab.
*
* Version of __slab_alloc to use when we know that preemption is
* already disabled (which is the case for bulk allocation).
*/
static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
unsigned long addr, struct kmem_cache_cpu *c, unsigned int orig_size)
{
void *freelist;
struct slab *slab;
unsigned long flags;
struct partial_context pc;
stat(s, ALLOC_SLOWPATH);
reread_slab:
slab = READ_ONCE(c->slab);
if (!slab) {
/*
* if the node is not online or has no normal memory, just
* ignore the node constraint
*/
if (unlikely(node != NUMA_NO_NODE &&
!node_isset(node, slab_nodes)))
node = NUMA_NO_NODE;
goto new_slab;
}
redo:
if (unlikely(!node_match(slab, node))) {
/*
* same as above but node_match() being false already
* implies node != NUMA_NO_NODE
*/
if (!node_isset(node, slab_nodes)) {
node = NUMA_NO_NODE;
} else {
stat(s, ALLOC_NODE_MISMATCH);
goto deactivate_slab;
}
}
/*
* By rights, we should be searching for a slab page that was
* PFMEMALLOC but right now, we are losing the pfmemalloc
* information when the page leaves the per-cpu allocator
*/
if (unlikely(!pfmemalloc_match(slab, gfpflags)))
goto deactivate_slab;
/* must check again c->slab in case we got preempted and it changed */
local_lock_irqsave(&s->cpu_slab->lock, flags);
if (unlikely(slab != c->slab)) {
local_unlock_irqrestore(&s->cpu_slab->lock, flags);
goto reread_slab;
}
freelist = c->freelist;
if (freelist)
goto load_freelist;
freelist = get_freelist(s, slab);
if (!freelist) {
c->slab = NULL;
c->tid = next_tid(c->tid);
local_unlock_irqrestore(&s->cpu_slab->lock, flags);
stat(s, DEACTIVATE_BYPASS);
goto new_slab;
}
stat(s, ALLOC_REFILL);
load_freelist:
lockdep_assert_held(this_cpu_ptr(&s->cpu_slab->lock));
/*
* freelist is pointing to the list of objects to be used.
* slab is pointing to the slab from which the objects are obtained.
* That slab must be frozen for per cpu allocations to work.
*/
VM_BUG_ON(!c->slab->frozen);
c->freelist = get_freepointer(s, freelist);
c->tid = next_tid(c->tid);
local_unlock_irqrestore(&s->cpu_slab->lock, flags);
return freelist;
deactivate_slab:
local_lock_irqsave(&s->cpu_slab->lock, flags);
if (slab != c->slab) {
local_unlock_irqrestore(&s->cpu_slab->lock, flags);
goto reread_slab;
}
freelist = c->freelist;
c->slab = NULL;
c->freelist = NULL;
c->tid = next_tid(c->tid);
local_unlock_irqrestore(&s->cpu_slab->lock, flags);
deactivate_slab(s, slab, freelist);
new_slab:
if (slub_percpu_partial(c)) {
local_lock_irqsave(&s->cpu_slab->lock, flags);
if (unlikely(c->slab)) {
local_unlock_irqrestore(&s->cpu_slab->lock, flags);
goto reread_slab;
}
if (unlikely(!slub_percpu_partial(c))) {
local_unlock_irqrestore(&s->cpu_slab->lock, flags);
/* we were preempted and partial list got empty */
goto new_objects;
}
slab = c->slab = slub_percpu_partial(c);
slub_set_percpu_partial(c, slab);
local_unlock_irqrestore(&s->cpu_slab->lock, flags);
stat(s, CPU_PARTIAL_ALLOC);
goto redo;
}
new_objects:
pc.flags = gfpflags;
pc.slab = &slab;
pc.orig_size = orig_size;
freelist = get_partial(s, node, &pc);
if (freelist)
goto check_new_slab;
slub_put_cpu_ptr(s->cpu_slab);
slab = new_slab(s, gfpflags, node);
c = slub_get_cpu_ptr(s->cpu_slab);
if (unlikely(!slab)) {
slab_out_of_memory(s, gfpflags, node);
return NULL;
}
stat(s, ALLOC_SLAB);
if (kmem_cache_debug(s)) {
freelist = alloc_single_from_new_slab(s, slab, orig_size);
if (unlikely(!freelist))
goto new_objects;
if (s->flags & SLAB_STORE_USER)
set_track(s, freelist, TRACK_ALLOC, addr);
return freelist;
}
/*
* No other reference to the slab yet so we can
* muck around with it freely without cmpxchg
*/
freelist = slab->freelist;
slab->freelist = NULL;
slab->inuse = slab->objects;
slab->frozen = 1;
inc_slabs_node(s, slab_nid(slab), slab->objects);
check_new_slab:
if (kmem_cache_debug(s)) {
/*
* For debug caches here we had to go through
* alloc_single_from_partial() so just store the tracking info
* and return the object
*/
if (s->flags & SLAB_STORE_USER)
set_track(s, freelist, TRACK_ALLOC, addr);
return freelist;
}
if (unlikely(!pfmemalloc_match(slab, gfpflags))) {
/*
* For !pfmemalloc_match() case we don't load freelist so that
* we don't make further mismatched allocations easier.
*/
deactivate_slab(s, slab, get_freepointer(s, freelist));
return freelist;
}
retry_load_slab:
local_lock_irqsave(&s->cpu_slab->lock, flags);
if (unlikely(c->slab)) {
void *flush_freelist = c->freelist;
struct slab *flush_slab = c->slab;
c->slab = NULL;
c->freelist = NULL;
c->tid = next_tid(c->tid);
local_unlock_irqrestore(&s->cpu_slab->lock, flags);
deactivate_slab(s, flush_slab, flush_freelist);
stat(s, CPUSLAB_FLUSH);
goto retry_load_slab;
}
c->slab = slab;
goto load_freelist;
}
/*
* A wrapper for ___slab_alloc() for contexts where preemption is not yet
* disabled. Compensates for possible cpu changes by refetching the per cpu area
* pointer.
*/
static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
unsigned long addr, struct kmem_cache_cpu *c, unsigned int orig_size)
{
void *p;
#ifdef CONFIG_PREEMPT_COUNT
/*
* We may have been preempted and rescheduled on a different
* cpu before disabling preemption. Need to reload cpu area
* pointer.
*/
c = slub_get_cpu_ptr(s->cpu_slab);
#endif
p = ___slab_alloc(s, gfpflags, node, addr, c, orig_size);
#ifdef CONFIG_PREEMPT_COUNT
slub_put_cpu_ptr(s->cpu_slab);
#endif
return p;
}
static __always_inline void *__slab_alloc_node(struct kmem_cache *s,
gfp_t gfpflags, int node, unsigned long addr, size_t orig_size)
{
struct kmem_cache_cpu *c;
struct slab *slab;
unsigned long tid;
void *object;
redo:
/*
* Must read kmem_cache cpu data via this cpu ptr. Preemption is
* enabled. We may switch back and forth between cpus while
* reading from one cpu area. That does not matter as long
* as we end up on the original cpu again when doing the cmpxchg.
*
* We must guarantee that tid and kmem_cache_cpu are retrieved on the
* same cpu. We read first the kmem_cache_cpu pointer and use it to read
* the tid. If we are preempted and switched to another cpu between the
* two reads, it's OK as the two are still associated with the same cpu
* and cmpxchg later will validate the cpu.
*/
c = raw_cpu_ptr(s->cpu_slab);
tid = READ_ONCE(c->tid);
/*
* Irqless object alloc/free algorithm used here depends on sequence
* of fetching cpu_slab's data. tid should be fetched before anything
* on c to guarantee that object and slab associated with previous tid
* won't be used with current tid. If we fetch tid first, object and
* slab could be one associated with next tid and our alloc/free
* request will be failed. In this case, we will retry. So, no problem.
*/
barrier();
/*
* The transaction ids are globally unique per cpu and per operation on
* a per cpu queue. Thus they can be guarantee that the cmpxchg_double
* occurs on the right processor and that there was no operation on the
* linked list in between.
*/
object = c->freelist;
slab = c->slab;
if (!USE_LOCKLESS_FAST_PATH() ||
unlikely(!object || !slab || !node_match(slab, node))) {
object = __slab_alloc(s, gfpflags, node, addr, c, orig_size);
} else {
void *next_object = get_freepointer_safe(s, object);
/*
* The cmpxchg will only match if there was no additional
* operation and if we are on the right processor.
*
* The cmpxchg does the following atomically (without lock
* semantics!)
* 1. Relocate first pointer to the current per cpu area.
* 2. Verify that tid and freelist have not been changed
* 3. If they were not changed replace tid and freelist
*
* Since this is without lock semantics the protection is only
* against code executing on this cpu *not* from access by
* other cpus.
*/
if (unlikely(!__update_cpu_freelist_fast(s, object, next_object, tid))) {
note_cmpxchg_failure("slab_alloc", s, tid);
goto redo;
}
prefetch_freepointer(s, next_object);
stat(s, ALLOC_FASTPATH);
}
return object;
}
#else /* CONFIG_SLUB_TINY */
static void *__slab_alloc_node(struct kmem_cache *s,
gfp_t gfpflags, int node, unsigned long addr, size_t orig_size)
{
struct partial_context pc;
struct slab *slab;
void *object;
pc.flags = gfpflags;
pc.slab = &slab;
pc.orig_size = orig_size;
object = get_partial(s, node, &pc);
if (object)
return object;
slab = new_slab(s, gfpflags, node);
if (unlikely(!slab)) {
slab_out_of_memory(s, gfpflags, node);
return NULL;
}
object = alloc_single_from_new_slab(s, slab, orig_size);
return object;
}
#endif /* CONFIG_SLUB_TINY */
/*
* If the object has been wiped upon free, make sure it's fully initialized by
* zeroing out freelist pointer.
*/
static __always_inline void maybe_wipe_obj_freeptr(struct kmem_cache *s,
void *obj)
{
if (unlikely(slab_want_init_on_free(s)) && obj)
memset((void *)((char *)kasan_reset_tag(obj) + s->offset),
0, sizeof(void *));
}
/*
* Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
* have the fastpath folded into their functions. So no function call
* overhead for requests that can be satisfied on the fastpath.
*
* The fastpath works by first checking if the lockless freelist can be used.
* If not then __slab_alloc is called for slow processing.
*
* Otherwise we can simply pick the next object from the lockless free list.
*/
static __fastpath_inline void *slab_alloc_node(struct kmem_cache *s, struct list_lru *lru,
gfp_t gfpflags, int node, unsigned long addr, size_t orig_size)
{
void *object;
struct obj_cgroup *objcg = NULL;
bool init = false;
s = slab_pre_alloc_hook(s, lru, &objcg, 1, gfpflags);
if (!s)
return NULL;
object = kfence_alloc(s, orig_size, gfpflags);
if (unlikely(object))
goto out;
object = __slab_alloc_node(s, gfpflags, node, addr, orig_size);
maybe_wipe_obj_freeptr(s, object);
init = slab_want_init_on_alloc(gfpflags, s);
out:
/*
* When init equals 'true', like for kzalloc() family, only
* @orig_size bytes might be zeroed instead of s->object_size
*/
slab_post_alloc_hook(s, objcg, gfpflags, 1, &object, init, orig_size);
return object;
}
static __fastpath_inline void *slab_alloc(struct kmem_cache *s, struct list_lru *lru,
gfp_t gfpflags, unsigned long addr, size_t orig_size)
{
return slab_alloc_node(s, lru, gfpflags, NUMA_NO_NODE, addr, orig_size);
}
static __fastpath_inline
void *__kmem_cache_alloc_lru(struct kmem_cache *s, struct list_lru *lru,
gfp_t gfpflags)
{
void *ret = slab_alloc(s, lru, gfpflags, _RET_IP_, s->object_size);
trace_kmem_cache_alloc(_RET_IP_, ret, s, gfpflags, NUMA_NO_NODE);
return ret;
}
void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
{
return __kmem_cache_alloc_lru(s, NULL, gfpflags);
}
EXPORT_SYMBOL(kmem_cache_alloc);
void *kmem_cache_alloc_lru(struct kmem_cache *s, struct list_lru *lru,
gfp_t gfpflags)
{
return __kmem_cache_alloc_lru(s, lru, gfpflags);
}
EXPORT_SYMBOL(kmem_cache_alloc_lru);
void *__kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags,
int node, size_t orig_size,
unsigned long caller)
{
return slab_alloc_node(s, NULL, gfpflags, node,
caller, orig_size);
}
void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
{
void *ret = slab_alloc_node(s, NULL, gfpflags, node, _RET_IP_, s->object_size);
trace_kmem_cache_alloc(_RET_IP_, ret, s, gfpflags, node);
return ret;
}
EXPORT_SYMBOL(kmem_cache_alloc_node);
static noinline void free_to_partial_list(
struct kmem_cache *s, struct slab *slab,
void *head, void *tail, int bulk_cnt,
unsigned long addr)
{
struct kmem_cache_node *n = get_node(s, slab_nid(slab));
struct slab *slab_free = NULL;
int cnt = bulk_cnt;
unsigned long flags;
depot_stack_handle_t handle = 0;
if (s->flags & SLAB_STORE_USER)
handle = set_track_prepare();
spin_lock_irqsave(&n->list_lock, flags);
if (free_debug_processing(s, slab, head, tail, &cnt, addr, handle)) {
void *prior = slab->freelist;
/* Perform the actual freeing while we still hold the locks */
slab->inuse -= cnt;
set_freepointer(s, tail, prior);
slab->freelist = head;
/*
* If the slab is empty, and node's partial list is full,
* it should be discarded anyway no matter it's on full or
* partial list.
*/
if (slab->inuse == 0 && n->nr_partial >= s->min_partial)
slab_free = slab;
if (!prior) {
/* was on full list */
remove_full(s, n, slab);
if (!slab_free) {
add_partial(n, slab, DEACTIVATE_TO_TAIL);
stat(s, FREE_ADD_PARTIAL);
}
} else if (slab_free) {
remove_partial(n, slab);
stat(s, FREE_REMOVE_PARTIAL);
}
}
if (slab_free) {
/*
* Update the counters while still holding n->list_lock to
* prevent spurious validation warnings
*/
dec_slabs_node(s, slab_nid(slab_free), slab_free->objects);
}
spin_unlock_irqrestore(&n->list_lock, flags);
if (slab_free) {
stat(s, FREE_SLAB);
free_slab(s, slab_free);
}
}
/*
* Slow path handling. This may still be called frequently since objects
* have a longer lifetime than the cpu slabs in most processing loads.
*
* So we still attempt to reduce cache line usage. Just take the slab
* lock and free the item. If there is no additional partial slab
* handling required then we can return immediately.
*/
static void __slab_free(struct kmem_cache *s, struct slab *slab,
void *head, void *tail, int cnt,
unsigned long addr)
{
void *prior;
int was_frozen;
struct slab new;
unsigned long counters;
struct kmem_cache_node *n = NULL;
unsigned long flags;
stat(s, FREE_SLOWPATH);
if (kfence_free(head))
return;
if (IS_ENABLED(CONFIG_SLUB_TINY) || kmem_cache_debug(s)) {
free_to_partial_list(s, slab, head, tail, cnt, addr);
return;
}
do {
if (unlikely(n)) {
spin_unlock_irqrestore(&n->list_lock, flags);
n = NULL;
}
prior = slab->freelist;
counters = slab->counters;
set_freepointer(s, tail, prior);
new.counters = counters;
was_frozen = new.frozen;
new.inuse -= cnt;
if ((!new.inuse || !prior) && !was_frozen) {
if (kmem_cache_has_cpu_partial(s) && !prior) {
/*
* Slab was on no list before and will be
* partially empty
* We can defer the list move and instead
* freeze it.
*/
new.frozen = 1;
} else { /* Needs to be taken off a list */
n = get_node(s, slab_nid(slab));
/*
* Speculatively acquire the list_lock.
* If the cmpxchg does not succeed then we may
* drop the list_lock without any processing.
*
* Otherwise the list_lock will synchronize with
* other processors updating the list of slabs.
*/
spin_lock_irqsave(&n->list_lock, flags);
}
}
} while (!slab_update_freelist(s, slab,
prior, counters,
head, new.counters,
"__slab_free"));
if (likely(!n)) {
if (likely(was_frozen)) {
/*
* The list lock was not taken therefore no list
* activity can be necessary.
*/
stat(s, FREE_FROZEN);
} else if (new.frozen) {
/*
* If we just froze the slab then put it onto the
* per cpu partial list.
*/
put_cpu_partial(s, slab, 1);
stat(s, CPU_PARTIAL_FREE);
}
return;
}
if (unlikely(!new.inuse && n->nr_partial >= s->min_partial))
goto slab_empty;
/*
* Objects left in the slab. If it was not on the partial list before
* then add it.
*/
if (!kmem_cache_has_cpu_partial(s) && unlikely(!prior)) {
remove_full(s, n, slab);
add_partial(n, slab, DEACTIVATE_TO_TAIL);
stat(s, FREE_ADD_PARTIAL);
}
spin_unlock_irqrestore(&n->list_lock, flags);
return;
slab_empty:
if (prior) {
/*
* Slab on the partial list.
*/
remove_partial(n, slab);
stat(s, FREE_REMOVE_PARTIAL);
} else {
/* Slab must be on the full list */
remove_full(s, n, slab);
}
spin_unlock_irqrestore(&n->list_lock, flags);
stat(s, FREE_SLAB);
discard_slab(s, slab);
}
#ifndef CONFIG_SLUB_TINY
/*
* Fastpath with forced inlining to produce a kfree and kmem_cache_free that
* can perform fastpath freeing without additional function calls.
*
* The fastpath is only possible if we are freeing to the current cpu slab
* of this processor. This typically the case if we have just allocated
* the item before.
*
* If fastpath is not possible then fall back to __slab_free where we deal
* with all sorts of special processing.
*
* Bulk free of a freelist with several objects (all pointing to the
* same slab) possible by specifying head and tail ptr, plus objects
* count (cnt). Bulk free indicated by tail pointer being set.
*/
static __always_inline void do_slab_free(struct kmem_cache *s,
struct slab *slab, void *head, void *tail,
int cnt, unsigned long addr)
{
void *tail_obj = tail ? : head;
struct kmem_cache_cpu *c;
unsigned long tid;
void **freelist;
redo:
/*
* Determine the currently cpus per cpu slab.
* The cpu may change afterward. However that does not matter since
* data is retrieved via this pointer. If we are on the same cpu
* during the cmpxchg then the free will succeed.
*/
c = raw_cpu_ptr(s->cpu_slab);
tid = READ_ONCE(c->tid);
/* Same with comment on barrier() in slab_alloc_node() */
barrier();
if (unlikely(slab != c->slab)) {
__slab_free(s, slab, head, tail_obj, cnt, addr);
return;
}
if (USE_LOCKLESS_FAST_PATH()) {
freelist = READ_ONCE(c->freelist);
set_freepointer(s, tail_obj, freelist);
if (unlikely(!__update_cpu_freelist_fast(s, freelist, head, tid))) {
note_cmpxchg_failure("slab_free", s, tid);
goto redo;
}
} else {
/* Update the free list under the local lock */
local_lock(&s->cpu_slab->lock);
c = this_cpu_ptr(s->cpu_slab);
if (unlikely(slab != c->slab)) {
local_unlock(&s->cpu_slab->lock);
goto redo;
}
tid = c->tid;
freelist = c->freelist;
set_freepointer(s, tail_obj, freelist);
c->freelist = head;
c->tid = next_tid(tid);
local_unlock(&s->cpu_slab->lock);
}
stat(s, FREE_FASTPATH);
}
#else /* CONFIG_SLUB_TINY */
static void do_slab_free(struct kmem_cache *s,
struct slab *slab, void *head, void *tail,
int cnt, unsigned long addr)
{
void *tail_obj = tail ? : head;
__slab_free(s, slab, head, tail_obj, cnt, addr);
}
#endif /* CONFIG_SLUB_TINY */
static __fastpath_inline void slab_free(struct kmem_cache *s, struct slab *slab,
void *head, void *tail, void **p, int cnt,
unsigned long addr)
{
memcg_slab_free_hook(s, slab, p, cnt);
/*
* With KASAN enabled slab_free_freelist_hook modifies the freelist
* to remove objects, whose reuse must be delayed.
*/
if (slab_free_freelist_hook(s, &head, &tail, &cnt))
do_slab_free(s, slab, head, tail, cnt, addr);
}
#ifdef CONFIG_KASAN_GENERIC
void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr)
{
do_slab_free(cache, virt_to_slab(x), x, NULL, 1, addr);
}
#endif
void __kmem_cache_free(struct kmem_cache *s, void *x, unsigned long caller)
{
slab_free(s, virt_to_slab(x), x, NULL, &x, 1, caller);
}
void kmem_cache_free(struct kmem_cache *s, void *x)
{
s = cache_from_obj(s, x);
if (!s)
return;
trace_kmem_cache_free(_RET_IP_, x, s);
slab_free(s, virt_to_slab(x), x, NULL, &x, 1, _RET_IP_);
}
EXPORT_SYMBOL(kmem_cache_free);
struct detached_freelist {
struct slab *slab;
void *tail;
void *freelist;
int cnt;
struct kmem_cache *s;
};
/*
* This function progressively scans the array with free objects (with
* a limited look ahead) and extract objects belonging to the same
* slab. It builds a detached freelist directly within the given
* slab/objects. This can happen without any need for
* synchronization, because the objects are owned by running process.
* The freelist is build up as a single linked list in the objects.
* The idea is, that this detached freelist can then be bulk
* transferred to the real freelist(s), but only requiring a single
* synchronization primitive. Look ahead in the array is limited due
* to performance reasons.
*/
static inline
int build_detached_freelist(struct kmem_cache *s, size_t size,
void **p, struct detached_freelist *df)
{
int lookahead = 3;
void *object;
struct folio *folio;
size_t same;
object = p[--size];
folio = virt_to_folio(object);
if (!s) {
/* Handle kalloc'ed objects */
if (unlikely(!folio_test_slab(folio))) {
free_large_kmalloc(folio, object);
df->slab = NULL;
return size;
}
/* Derive kmem_cache from object */
df->slab = folio_slab(folio);
df->s = df->slab->slab_cache;
} else {
df->slab = folio_slab(folio);
df->s = cache_from_obj(s, object); /* Support for memcg */
}
/* Start new detached freelist */
df->tail = object;
df->freelist = object;
df->cnt = 1;
if (is_kfence_address(object))
return size;
set_freepointer(df->s, object, NULL);
same = size;
while (size) {
object = p[--size];
/* df->slab is always set at this point */
if (df->slab == virt_to_slab(object)) {
/* Opportunity build freelist */
set_freepointer(df->s, object, df->freelist);
df->freelist = object;
df->cnt++;
same--;
if (size != same)
swap(p[size], p[same]);
continue;
}
/* Limit look ahead search */
if (!--lookahead)
break;
}
return same;
}
/* Note that interrupts must be enabled when calling this function. */
void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
{
if (!size)
return;
do {
struct detached_freelist df;
size = build_detached_freelist(s, size, p, &df);
if (!df.slab)
continue;
slab_free(df.s, df.slab, df.freelist, df.tail, &p[size], df.cnt,
_RET_IP_);
} while (likely(size));
}
EXPORT_SYMBOL(kmem_cache_free_bulk);
#ifndef CONFIG_SLUB_TINY
static inline int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags,
size_t size, void **p, struct obj_cgroup *objcg)
{
struct kmem_cache_cpu *c;
unsigned long irqflags;
int i;
/*
* Drain objects in the per cpu slab, while disabling local
* IRQs, which protects against PREEMPT and interrupts
* handlers invoking normal fastpath.
*/
c = slub_get_cpu_ptr(s->cpu_slab);
local_lock_irqsave(&s->cpu_slab->lock, irqflags);
for (i = 0; i < size; i++) {
void *object = kfence_alloc(s, s->object_size, flags);
if (unlikely(object)) {
p[i] = object;
continue;
}
object = c->freelist;
if (unlikely(!object)) {
/*
* We may have removed an object from c->freelist using
* the fastpath in the previous iteration; in that case,
* c->tid has not been bumped yet.
* Since ___slab_alloc() may reenable interrupts while
* allocating memory, we should bump c->tid now.
*/
c->tid = next_tid(c->tid);
local_unlock_irqrestore(&s->cpu_slab->lock, irqflags);
/*
* Invoking slow path likely have side-effect
* of re-populating per CPU c->freelist
*/
p[i] = ___slab_alloc(s, flags, NUMA_NO_NODE,
_RET_IP_, c, s->object_size);
if (unlikely(!p[i]))
goto error;
c = this_cpu_ptr(s->cpu_slab);
maybe_wipe_obj_freeptr(s, p[i]);
local_lock_irqsave(&s->cpu_slab->lock, irqflags);
continue; /* goto for-loop */
}
c->freelist = get_freepointer(s, object);
p[i] = object;
maybe_wipe_obj_freeptr(s, p[i]);
}
c->tid = next_tid(c->tid);
local_unlock_irqrestore(&s->cpu_slab->lock, irqflags);
slub_put_cpu_ptr(s->cpu_slab);
return i;
error:
slub_put_cpu_ptr(s->cpu_slab);
slab_post_alloc_hook(s, objcg, flags, i, p, false, s->object_size);
kmem_cache_free_bulk(s, i, p);
return 0;
}
#else /* CONFIG_SLUB_TINY */
static int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags,
size_t size, void **p, struct obj_cgroup *objcg)
{
int i;
for (i = 0; i < size; i++) {
void *object = kfence_alloc(s, s->object_size, flags);
if (unlikely(object)) {
p[i] = object;
continue;
}
p[i] = __slab_alloc_node(s, flags, NUMA_NO_NODE,
_RET_IP_, s->object_size);
if (unlikely(!p[i]))
goto error;
maybe_wipe_obj_freeptr(s, p[i]);
}
return i;
error:
slab_post_alloc_hook(s, objcg, flags, i, p, false, s->object_size);
kmem_cache_free_bulk(s, i, p);
return 0;
}
#endif /* CONFIG_SLUB_TINY */
/* Note that interrupts must be enabled when calling this function. */
int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
void **p)
{
int i;
struct obj_cgroup *objcg = NULL;
if (!size)
return 0;
/* memcg and kmem_cache debug support */
s = slab_pre_alloc_hook(s, NULL, &objcg, size, flags);
if (unlikely(!s))
return 0;
i = __kmem_cache_alloc_bulk(s, flags, size, p, objcg);
/*
* memcg and kmem_cache debug support and memory initialization.
* Done outside of the IRQ disabled fastpath loop.
*/
if (i != 0)
slab_post_alloc_hook(s, objcg, flags, size, p,
slab_want_init_on_alloc(flags, s), s->object_size);
return i;
}
EXPORT_SYMBOL(kmem_cache_alloc_bulk);
/*
* Object placement in a slab is made very easy because we always start at
* offset 0. If we tune the size of the object to the alignment then we can
* get the required alignment by putting one properly sized object after
* another.
*
* Notice that the allocation order determines the sizes of the per cpu
* caches. Each processor has always one slab available for allocations.
* Increasing the allocation order reduces the number of times that slabs
* must be moved on and off the partial lists and is therefore a factor in
* locking overhead.
*/
/*
* Minimum / Maximum order of slab pages. This influences locking overhead
* and slab fragmentation. A higher order reduces the number of partial slabs
* and increases the number of allocations possible without having to
* take the list_lock.
*/
static unsigned int slub_min_order;
static unsigned int slub_max_order =
IS_ENABLED(CONFIG_SLUB_TINY) ? 1 : PAGE_ALLOC_COSTLY_ORDER;
static unsigned int slub_min_objects;
/*
* Calculate the order of allocation given an slab object size.
*
* The order of allocation has significant impact on performance and other
* system components. Generally order 0 allocations should be preferred since
* order 0 does not cause fragmentation in the page allocator. Larger objects
* be problematic to put into order 0 slabs because there may be too much
* unused space left. We go to a higher order if more than 1/16th of the slab
* would be wasted.
*
* In order to reach satisfactory performance we must ensure that a minimum
* number of objects is in one slab. Otherwise we may generate too much
* activity on the partial lists which requires taking the list_lock. This is
* less a concern for large slabs though which are rarely used.
*
* slub_max_order specifies the order where we begin to stop considering the
* number of objects in a slab as critical. If we reach slub_max_order then
* we try to keep the page order as low as possible. So we accept more waste
* of space in favor of a small page order.
*
* Higher order allocations also allow the placement of more objects in a
* slab and thereby reduce object handling overhead. If the user has
* requested a higher minimum order then we start with that one instead of
* the smallest order which will fit the object.
*/
static inline unsigned int calc_slab_order(unsigned int size,
unsigned int min_objects, unsigned int max_order,
unsigned int fract_leftover)
{
unsigned int min_order = slub_min_order;
unsigned int order;
if (order_objects(min_order, size) > MAX_OBJS_PER_PAGE)
return get_order(size * MAX_OBJS_PER_PAGE) - 1;
for (order = max(min_order, (unsigned int)get_order(min_objects * size));
order <= max_order; order++) {
unsigned int slab_size = (unsigned int)PAGE_SIZE << order;
unsigned int rem;
rem = slab_size % size;
if (rem <= slab_size / fract_leftover)
break;
}
return order;
}
static inline int calculate_order(unsigned int size)
{
unsigned int order;
unsigned int min_objects;
unsigned int max_objects;
unsigned int nr_cpus;
/*
* Attempt to find best configuration for a slab. This
* works by first attempting to generate a layout with
* the best configuration and backing off gradually.
*
* First we increase the acceptable waste in a slab. Then
* we reduce the minimum objects required in a slab.
*/
min_objects = slub_min_objects;
if (!min_objects) {
/*
* Some architectures will only update present cpus when
* onlining them, so don't trust the number if it's just 1. But
* we also don't want to use nr_cpu_ids always, as on some other
* architectures, there can be many possible cpus, but never
* onlined. Here we compromise between trying to avoid too high
* order on systems that appear larger than they are, and too
* low order on systems that appear smaller than they are.
*/
nr_cpus = num_present_cpus();
if (nr_cpus <= 1)
nr_cpus = nr_cpu_ids;
min_objects = 4 * (fls(nr_cpus) + 1);
}
max_objects = order_objects(slub_max_order, size);
min_objects = min(min_objects, max_objects);
while (min_objects > 1) {
unsigned int fraction;
fraction = 16;
while (fraction >= 4) {
order = calc_slab_order(size, min_objects,
slub_max_order, fraction);
if (order <= slub_max_order)
return order;
fraction /= 2;
}
min_objects--;
}
/*
* We were unable to place multiple objects in a slab. Now
* lets see if we can place a single object there.
*/
order = calc_slab_order(size, 1, slub_max_order, 1);
if (order <= slub_max_order)
return order;
/*
* Doh this slab cannot be placed using slub_max_order.
*/
order = calc_slab_order(size, 1, MAX_ORDER, 1);
if (order <= MAX_ORDER)
return order;
return -ENOSYS;
}
static void
init_kmem_cache_node(struct kmem_cache_node *n)
{
n->nr_partial = 0;
spin_lock_init(&n->list_lock);
INIT_LIST_HEAD(&n->partial);
#ifdef CONFIG_SLUB_DEBUG
atomic_long_set(&n->nr_slabs, 0);
atomic_long_set(&n->total_objects, 0);
INIT_LIST_HEAD(&n->full);
#endif
}
#ifndef CONFIG_SLUB_TINY
static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
{
BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
NR_KMALLOC_TYPES * KMALLOC_SHIFT_HIGH *
sizeof(struct kmem_cache_cpu));
/*
* Must align to double word boundary for the double cmpxchg
* instructions to work; see __pcpu_double_call_return_bool().
*/
s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu),
2 * sizeof(void *));
if (!s->cpu_slab)
return 0;
init_kmem_cache_cpus(s);
return 1;
}
#else
static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
{
return 1;
}
#endif /* CONFIG_SLUB_TINY */
static struct kmem_cache *kmem_cache_node;
/*
* No kmalloc_node yet so do it by hand. We know that this is the first
* slab on the node for this slabcache. There are no concurrent accesses
* possible.
*
* Note that this function only works on the kmem_cache_node
* when allocating for the kmem_cache_node. This is used for bootstrapping
* memory on a fresh node that has no slab structures yet.
*/
static void early_kmem_cache_node_alloc(int node)
{
struct slab *slab;
struct kmem_cache_node *n;
BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
slab = new_slab(kmem_cache_node, GFP_NOWAIT, node);
BUG_ON(!slab);
inc_slabs_node(kmem_cache_node, slab_nid(slab), slab->objects);
if (slab_nid(slab) != node) {
pr_err("SLUB: Unable to allocate memory from node %d\n", node);
pr_err("SLUB: Allocating a useless per node structure in order to be able to continue\n");
}
n = slab->freelist;
BUG_ON(!n);
#ifdef CONFIG_SLUB_DEBUG
init_object(kmem_cache_node, n, SLUB_RED_ACTIVE);
init_tracking(kmem_cache_node, n);
#endif
n = kasan_slab_alloc(kmem_cache_node, n, GFP_KERNEL, false);
slab->freelist = get_freepointer(kmem_cache_node, n);
slab->inuse = 1;
kmem_cache_node->node[node] = n;
init_kmem_cache_node(n);
inc_slabs_node(kmem_cache_node, node, slab->objects);
/*
* No locks need to be taken here as it has just been
* initialized and there is no concurrent access.
*/
__add_partial(n, slab, DEACTIVATE_TO_HEAD);
}
static void free_kmem_cache_nodes(struct kmem_cache *s)
{
int node;
struct kmem_cache_node *n;
for_each_kmem_cache_node(s, node, n) {
s->node[node] = NULL;
kmem_cache_free(kmem_cache_node, n);
}
}
void __kmem_cache_release(struct kmem_cache *s)
{
cache_random_seq_destroy(s);
#ifndef CONFIG_SLUB_TINY
free_percpu(s->cpu_slab);
#endif
free_kmem_cache_nodes(s);
}
static int init_kmem_cache_nodes(struct kmem_cache *s)
{
int node;
for_each_node_mask(node, slab_nodes) {
struct kmem_cache_node *n;
if (slab_state == DOWN) {
early_kmem_cache_node_alloc(node);
continue;
}
n = kmem_cache_alloc_node(kmem_cache_node,
GFP_KERNEL, node);
if (!n) {
free_kmem_cache_nodes(s);
return 0;
}
init_kmem_cache_node(n);
s->node[node] = n;
}
return 1;
}
static void set_cpu_partial(struct kmem_cache *s)
{
#ifdef CONFIG_SLUB_CPU_PARTIAL
unsigned int nr_objects;
/*
* cpu_partial determined the maximum number of objects kept in the
* per cpu partial lists of a processor.
*
* Per cpu partial lists mainly contain slabs that just have one
* object freed. If they are used for allocation then they can be
* filled up again with minimal effort. The slab will never hit the
* per node partial lists and therefore no locking will be required.
*
* For backwards compatibility reasons, this is determined as number
* of objects, even though we now limit maximum number of pages, see
* slub_set_cpu_partial()
*/
if (!kmem_cache_has_cpu_partial(s))
nr_objects = 0;
else if (s->size >= PAGE_SIZE)
nr_objects = 6;
else if (s->size >= 1024)
nr_objects = 24;
else if (s->size >= 256)
nr_objects = 52;
else
nr_objects = 120;
slub_set_cpu_partial(s, nr_objects);
#endif
}
/*
* calculate_sizes() determines the order and the distribution of data within
* a slab object.
*/
static int calculate_sizes(struct kmem_cache *s)
{
slab_flags_t flags = s->flags;
unsigned int size = s->object_size;
unsigned int order;
/*
* Round up object size to the next word boundary. We can only
* place the free pointer at word boundaries and this determines
* the possible location of the free pointer.
*/
size = ALIGN(size, sizeof(void *));
#ifdef CONFIG_SLUB_DEBUG
/*
* Determine if we can poison the object itself. If the user of
* the slab may touch the object after free or before allocation
* then we should never poison the object itself.
*/
if ((flags & SLAB_POISON) && !(flags & SLAB_TYPESAFE_BY_RCU) &&
!s->ctor)
s->flags |= __OBJECT_POISON;
else
s->flags &= ~__OBJECT_POISON;
/*
* If we are Redzoning then check if there is some space between the
* end of the object and the free pointer. If not then add an
* additional word to have some bytes to store Redzone information.
*/
if ((flags & SLAB_RED_ZONE) && size == s->object_size)
size += sizeof(void *);
#endif
/*
* With that we have determined the number of bytes in actual use
* by the object and redzoning.
*/
s->inuse = size;
if (slub_debug_orig_size(s) ||
(flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)) ||
((flags & SLAB_RED_ZONE) && s->object_size < sizeof(void *)) ||
s->ctor) {
/*
* Relocate free pointer after the object if it is not
* permitted to overwrite the first word of the object on
* kmem_cache_free.
*
* This is the case if we do RCU, have a constructor or
* destructor, are poisoning the objects, or are
* redzoning an object smaller than sizeof(void *).
*
* The assumption that s->offset >= s->inuse means free
* pointer is outside of the object is used in the
* freeptr_outside_object() function. If that is no
* longer true, the function needs to be modified.
*/
s->offset = size;
size += sizeof(void *);
} else {
/*
* Store freelist pointer near middle of object to keep
* it away from the edges of the object to avoid small
* sized over/underflows from neighboring allocations.
*/
s->offset = ALIGN_DOWN(s->object_size / 2, sizeof(void *));
}
#ifdef CONFIG_SLUB_DEBUG
if (flags & SLAB_STORE_USER) {
/*
* Need to store information about allocs and frees after
* the object.
*/
size += 2 * sizeof(struct track);
/* Save the original kmalloc request size */
if (flags & SLAB_KMALLOC)
size += sizeof(unsigned int);
}
#endif
kasan_cache_create(s, &size, &s->flags);
#ifdef CONFIG_SLUB_DEBUG
if (flags & SLAB_RED_ZONE) {
/*
* Add some empty padding so that we can catch
* overwrites from earlier objects rather than let
* tracking information or the free pointer be
* corrupted if a user writes before the start
* of the object.
*/
size += sizeof(void *);
s->red_left_pad = sizeof(void *);
s->red_left_pad = ALIGN(s->red_left_pad, s->align);
size += s->red_left_pad;
}
#endif
/*
* SLUB stores one object immediately after another beginning from
* offset 0. In order to align the objects we have to simply size
* each object to conform to the alignment.
*/
size = ALIGN(size, s->align);
s->size = size;
s->reciprocal_size = reciprocal_value(size);
order = calculate_order(size);
if ((int)order < 0)
return 0;
s->allocflags = 0;
if (order)
s->allocflags |= __GFP_COMP;
if (s->flags & SLAB_CACHE_DMA)
s->allocflags |= GFP_DMA;
if (s->flags & SLAB_CACHE_DMA32)
s->allocflags |= GFP_DMA32;
if (s->flags & SLAB_RECLAIM_ACCOUNT)
s->allocflags |= __GFP_RECLAIMABLE;
/*
* Determine the number of objects per slab
*/
s->oo = oo_make(order, size);
s->min = oo_make(get_order(size), size);
return !!oo_objects(s->oo);
}
static int kmem_cache_open(struct kmem_cache *s, slab_flags_t flags)
{
s->flags = kmem_cache_flags(s->size, flags, s->name);
#ifdef CONFIG_SLAB_FREELIST_HARDENED
s->random = get_random_long();
#endif
if (!calculate_sizes(s))
goto error;
if (disable_higher_order_debug) {
/*
* Disable debugging flags that store metadata if the min slab
* order increased.
*/
if (get_order(s->size) > get_order(s->object_size)) {
s->flags &= ~DEBUG_METADATA_FLAGS;
s->offset = 0;
if (!calculate_sizes(s))
goto error;
}
}
#ifdef system_has_freelist_aba
if (system_has_freelist_aba() && !(s->flags & SLAB_NO_CMPXCHG)) {
/* Enable fast mode */
s->flags |= __CMPXCHG_DOUBLE;
}
#endif
/*
* The larger the object size is, the more slabs we want on the partial
* list to avoid pounding the page allocator excessively.
*/
s->min_partial = min_t(unsigned long, MAX_PARTIAL, ilog2(s->size) / 2);
s->min_partial = max_t(unsigned long, MIN_PARTIAL, s->min_partial);
set_cpu_partial(s);
#ifdef CONFIG_NUMA
s->remote_node_defrag_ratio = 1000;
#endif
/* Initialize the pre-computed randomized freelist if slab is up */
if (slab_state >= UP) {
if (init_cache_random_seq(s))
goto error;
}
if (!init_kmem_cache_nodes(s))
goto error;
if (alloc_kmem_cache_cpus(s))
return 0;
error:
__kmem_cache_release(s);
return -EINVAL;
}
static void list_slab_objects(struct kmem_cache *s, struct slab *slab,
const char *text)
{
#ifdef CONFIG_SLUB_DEBUG
void *addr = slab_address(slab);
void *p;
slab_err(s, slab, text, s->name);
spin_lock(&object_map_lock);
__fill_map(object_map, s, slab);
for_each_object(p, s, addr, slab->objects) {
if (!test_bit(__obj_to_index(s, addr, p), object_map)) {
pr_err("Object 0x%p @offset=%tu\n", p, p - addr);
print_tracking(s, p);
}
}
spin_unlock(&object_map_lock);
#endif
}
/*
* Attempt to free all partial slabs on a node.
* This is called from __kmem_cache_shutdown(). We must take list_lock
* because sysfs file might still access partial list after the shutdowning.
*/
static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
{
LIST_HEAD(discard);
struct slab *slab, *h;
BUG_ON(irqs_disabled());
spin_lock_irq(&n->list_lock);
list_for_each_entry_safe(slab, h, &n->partial, slab_list) {
if (!slab->inuse) {
remove_partial(n, slab);
list_add(&slab->slab_list, &discard);
} else {
list_slab_objects(s, slab,
"Objects remaining in %s on __kmem_cache_shutdown()");
}
}
spin_unlock_irq(&n->list_lock);
list_for_each_entry_safe(slab, h, &discard, slab_list)
discard_slab(s, slab);
}
bool __kmem_cache_empty(struct kmem_cache *s)
{
int node;
struct kmem_cache_node *n;
for_each_kmem_cache_node(s, node, n)
if (n->nr_partial || node_nr_slabs(n))
return false;
return true;
}
/*
* Release all resources used by a slab cache.
*/
int __kmem_cache_shutdown(struct kmem_cache *s)
{
int node;
struct kmem_cache_node *n;
flush_all_cpus_locked(s);
/* Attempt to free all objects */
for_each_kmem_cache_node(s, node, n) {
free_partial(s, n);
if (n->nr_partial || node_nr_slabs(n))
return 1;
}
return 0;
}
#ifdef CONFIG_PRINTK
void __kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab)
{
void *base;
int __maybe_unused i;
unsigned int objnr;
void *objp;
void *objp0;
struct kmem_cache *s = slab->slab_cache;
struct track __maybe_unused *trackp;
kpp->kp_ptr = object;
kpp->kp_slab = slab;
kpp->kp_slab_cache = s;
base = slab_address(slab);
objp0 = kasan_reset_tag(object);
#ifdef CONFIG_SLUB_DEBUG
objp = restore_red_left(s, objp0);
#else
objp = objp0;
#endif
objnr = obj_to_index(s, slab, objp);
kpp->kp_data_offset = (unsigned long)((char *)objp0 - (char *)objp);
objp = base + s->size * objnr;
kpp->kp_objp = objp;
if (WARN_ON_ONCE(objp < base || objp >= base + slab->objects * s->size
|| (objp - base) % s->size) ||
!(s->flags & SLAB_STORE_USER))
return;
#ifdef CONFIG_SLUB_DEBUG
objp = fixup_red_left(s, objp);
trackp = get_track(s, objp, TRACK_ALLOC);
kpp->kp_ret = (void *)trackp->addr;
#ifdef CONFIG_STACKDEPOT
{
depot_stack_handle_t handle;
unsigned long *entries;
unsigned int nr_entries;
handle = READ_ONCE(trackp->handle);
if (handle) {
nr_entries = stack_depot_fetch(handle, &entries);
for (i = 0; i < KS_ADDRS_COUNT && i < nr_entries; i++)
kpp->kp_stack[i] = (void *)entries[i];
}
trackp = get_track(s, objp, TRACK_FREE);
handle = READ_ONCE(trackp->handle);
if (handle) {
nr_entries = stack_depot_fetch(handle, &entries);
for (i = 0; i < KS_ADDRS_COUNT && i < nr_entries; i++)
kpp->kp_free_stack[i] = (void *)entries[i];
}
}
#endif
#endif
}
#endif
/********************************************************************
* Kmalloc subsystem
*******************************************************************/
static int __init setup_slub_min_order(char *str)
{
get_option(&str, (int *)&slub_min_order);
return 1;
}
__setup("slub_min_order=", setup_slub_min_order);
static int __init setup_slub_max_order(char *str)
{
get_option(&str, (int *)&slub_max_order);
slub_max_order = min_t(unsigned int, slub_max_order, MAX_ORDER);
return 1;
}
__setup("slub_max_order=", setup_slub_max_order);
static int __init setup_slub_min_objects(char *str)
{
get_option(&str, (int *)&slub_min_objects);
return 1;
}
__setup("slub_min_objects=", setup_slub_min_objects);
#ifdef CONFIG_HARDENED_USERCOPY
/*
* Rejects incorrectly sized objects and objects that are to be copied
* to/from userspace but do not fall entirely within the containing slab
* cache's usercopy region.
*
* Returns NULL if check passes, otherwise const char * to name of cache
* to indicate an error.
*/
void __check_heap_object(const void *ptr, unsigned long n,
const struct slab *slab, bool to_user)
{
struct kmem_cache *s;
unsigned int offset;
bool is_kfence = is_kfence_address(ptr);
ptr = kasan_reset_tag(ptr);
/* Find object and usable object size. */
s = slab->slab_cache;
/* Reject impossible pointers. */
if (ptr < slab_address(slab))
usercopy_abort("SLUB object not in SLUB page?!", NULL,
to_user, 0, n);
/* Find offset within object. */
if (is_kfence)
offset = ptr - kfence_object_start(ptr);
else
offset = (ptr - slab_address(slab)) % s->size;
/* Adjust for redzone and reject if within the redzone. */
if (!is_kfence && kmem_cache_debug_flags(s, SLAB_RED_ZONE)) {
if (offset < s->red_left_pad)
usercopy_abort("SLUB object in left red zone",
s->name, to_user, offset, n);
offset -= s->red_left_pad;
}
/* Allow address range falling entirely within usercopy region. */
if (offset >= s->useroffset &&
offset - s->useroffset <= s->usersize &&
n <= s->useroffset - offset + s->usersize)
return;
usercopy_abort("SLUB object", s->name, to_user, offset, n);
}
#endif /* CONFIG_HARDENED_USERCOPY */
#define SHRINK_PROMOTE_MAX 32
/*
* kmem_cache_shrink discards empty slabs and promotes the slabs filled
* up most to the head of the partial lists. New allocations will then
* fill those up and thus they can be removed from the partial lists.
*
* The slabs with the least items are placed last. This results in them
* being allocated from last increasing the chance that the last objects
* are freed in them.
*/
static int __kmem_cache_do_shrink(struct kmem_cache *s)
{
int node;
int i;
struct kmem_cache_node *n;
struct slab *slab;
struct slab *t;
struct list_head discard;
struct list_head promote[SHRINK_PROMOTE_MAX];
unsigned long flags;
int ret = 0;
for_each_kmem_cache_node(s, node, n) {
INIT_LIST_HEAD(&discard);
for (i = 0; i < SHRINK_PROMOTE_MAX; i++)
INIT_LIST_HEAD(promote + i);
spin_lock_irqsave(&n->list_lock, flags);
/*
* Build lists of slabs to discard or promote.
*
* Note that concurrent frees may occur while we hold the
* list_lock. slab->inuse here is the upper limit.
*/
list_for_each_entry_safe(slab, t, &n->partial, slab_list) {
int free = slab->objects - slab->inuse;
/* Do not reread slab->inuse */
barrier();
/* We do not keep full slabs on the list */
BUG_ON(free <= 0);
if (free == slab->objects) {
list_move(&slab->slab_list, &discard);
n->nr_partial--;
dec_slabs_node(s, node, slab->objects);
} else if (free <= SHRINK_PROMOTE_MAX)
list_move(&slab->slab_list, promote + free - 1);
}
/*
* Promote the slabs filled up most to the head of the
* partial list.
*/
for (i = SHRINK_PROMOTE_MAX - 1; i >= 0; i--)
list_splice(promote + i, &n->partial);
spin_unlock_irqrestore(&n->list_lock, flags);
/* Release empty slabs */
list_for_each_entry_safe(slab, t, &discard, slab_list)
free_slab(s, slab);
if (node_nr_slabs(n))
ret = 1;
}
return ret;
}
int __kmem_cache_shrink(struct kmem_cache *s)
{
flush_all(s);
return __kmem_cache_do_shrink(s);
}
static int slab_mem_going_offline_callback(void *arg)
{
struct kmem_cache *s;
mutex_lock(&slab_mutex);
list_for_each_entry(s, &slab_caches, list) {
flush_all_cpus_locked(s);
__kmem_cache_do_shrink(s);
}
mutex_unlock(&slab_mutex);
return 0;
}
static void slab_mem_offline_callback(void *arg)
{
struct memory_notify *marg = arg;
int offline_node;
offline_node = marg->status_change_nid_normal;
/*
* If the node still has available memory. we need kmem_cache_node
* for it yet.
*/
if (offline_node < 0)
return;
mutex_lock(&slab_mutex);
node_clear(offline_node, slab_nodes);
/*
* We no longer free kmem_cache_node structures here, as it would be
* racy with all get_node() users, and infeasible to protect them with
* slab_mutex.
*/
mutex_unlock(&slab_mutex);
}
static int slab_mem_going_online_callback(void *arg)
{
struct kmem_cache_node *n;
struct kmem_cache *s;
struct memory_notify *marg = arg;
int nid = marg->status_change_nid_normal;
int ret = 0;
/*
* If the node's memory is already available, then kmem_cache_node is
* already created. Nothing to do.
*/
if (nid < 0)
return 0;
/*
* We are bringing a node online. No memory is available yet. We must
* allocate a kmem_cache_node structure in order to bring the node
* online.
*/
mutex_lock(&slab_mutex);
list_for_each_entry(s, &slab_caches, list) {
/*
* The structure may already exist if the node was previously
* onlined and offlined.
*/
if (get_node(s, nid))
continue;
/*
* XXX: kmem_cache_alloc_node will fallback to other nodes
* since memory is not yet available from the node that
* is brought up.
*/
n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL);
if (!n) {
ret = -ENOMEM;
goto out;
}
init_kmem_cache_node(n);
s->node[nid] = n;
}
/*
* Any cache created after this point will also have kmem_cache_node
* initialized for the new node.
*/
node_set(nid, slab_nodes);
out:
mutex_unlock(&slab_mutex);
return ret;
}
static int slab_memory_callback(struct notifier_block *self,
unsigned long action, void *arg)
{
int ret = 0;
switch (action) {
case MEM_GOING_ONLINE:
ret = slab_mem_going_online_callback(arg);
break;
case MEM_GOING_OFFLINE:
ret = slab_mem_going_offline_callback(arg);
break;
case MEM_OFFLINE:
case MEM_CANCEL_ONLINE:
slab_mem_offline_callback(arg);
break;
case MEM_ONLINE:
case MEM_CANCEL_OFFLINE:
break;
}
if (ret)
ret = notifier_from_errno(ret);
else
ret = NOTIFY_OK;
return ret;
}
/********************************************************************
* Basic setup of slabs
*******************************************************************/
/*
* Used for early kmem_cache structures that were allocated using
* the page allocator. Allocate them properly then fix up the pointers
* that may be pointing to the wrong kmem_cache structure.
*/
static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache)
{
int node;
struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
struct kmem_cache_node *n;
memcpy(s, static_cache, kmem_cache->object_size);
/*
* This runs very early, and only the boot processor is supposed to be
* up. Even if it weren't true, IRQs are not up so we couldn't fire
* IPIs around.
*/
__flush_cpu_slab(s, smp_processor_id());
for_each_kmem_cache_node(s, node, n) {
struct slab *p;
list_for_each_entry(p, &n->partial, slab_list)
p->slab_cache = s;
#ifdef CONFIG_SLUB_DEBUG
list_for_each_entry(p, &n->full, slab_list)
p->slab_cache = s;
#endif
}
list_add(&s->list, &slab_caches);
return s;
}
void __init kmem_cache_init(void)
{
static __initdata struct kmem_cache boot_kmem_cache,
boot_kmem_cache_node;
int node;
if (debug_guardpage_minorder())
slub_max_order = 0;
/* Print slub debugging pointers without hashing */
if (__slub_debug_enabled())
no_hash_pointers_enable(NULL);
kmem_cache_node = &boot_kmem_cache_node;
kmem_cache = &boot_kmem_cache;
/*
* Initialize the nodemask for which we will allocate per node
* structures. Here we don't need taking slab_mutex yet.
*/
for_each_node_state(node, N_NORMAL_MEMORY)
node_set(node, slab_nodes);
create_boot_cache(kmem_cache_node, "kmem_cache_node",
sizeof(struct kmem_cache_node), SLAB_HWCACHE_ALIGN, 0, 0);
hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
/* Able to allocate the per node structures */
slab_state = PARTIAL;
create_boot_cache(kmem_cache, "kmem_cache",
offsetof(struct kmem_cache, node) +
nr_node_ids * sizeof(struct kmem_cache_node *),
SLAB_HWCACHE_ALIGN, 0, 0);
kmem_cache = bootstrap(&boot_kmem_cache);
kmem_cache_node = bootstrap(&boot_kmem_cache_node);
/* Now we can use the kmem_cache to allocate kmalloc slabs */
setup_kmalloc_cache_index_table();
create_kmalloc_caches(0);
/* Setup random freelists for each cache */
init_freelist_randomization();
cpuhp_setup_state_nocalls(CPUHP_SLUB_DEAD, "slub:dead", NULL,
slub_cpu_dead);
pr_info("SLUB: HWalign=%d, Order=%u-%u, MinObjects=%u, CPUs=%u, Nodes=%u\n",
cache_line_size(),
slub_min_order, slub_max_order, slub_min_objects,
nr_cpu_ids, nr_node_ids);
}
void __init kmem_cache_init_late(void)
{
#ifndef CONFIG_SLUB_TINY
flushwq = alloc_workqueue("slub_flushwq", WQ_MEM_RECLAIM, 0);
WARN_ON(!flushwq);
#endif
}
struct kmem_cache *
__kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
slab_flags_t flags, void (*ctor)(void *))
{
struct kmem_cache *s;
s = find_mergeable(size, align, flags, name, ctor);
if (s) {
if (sysfs_slab_alias(s, name))
return NULL;
s->refcount++;
/*
* Adjust the object sizes so that we clear
* the complete object on kzalloc.
*/
s->object_size = max(s->object_size, size);
s->inuse = max(s->inuse, ALIGN(size, sizeof(void *)));
}
return s;
}
int __kmem_cache_create(struct kmem_cache *s, slab_flags_t flags)
{
int err;
err = kmem_cache_open(s, flags);
if (err)
return err;
/* Mutex is not taken during early boot */
if (slab_state <= UP)
return 0;
err = sysfs_slab_add(s);
if (err) {
__kmem_cache_release(s);
return err;
}
if (s->flags & SLAB_STORE_USER)
debugfs_slab_add(s);
return 0;
}
#ifdef SLAB_SUPPORTS_SYSFS
static int count_inuse(struct slab *slab)
{
return slab->inuse;
}
static int count_total(struct slab *slab)
{
return slab->objects;
}
#endif
#ifdef CONFIG_SLUB_DEBUG
static void validate_slab(struct kmem_cache *s, struct slab *slab,
unsigned long *obj_map)
{
void *p;
void *addr = slab_address(slab);
if (!check_slab(s, slab) || !on_freelist(s, slab, NULL))
return;
/* Now we know that a valid freelist exists */
__fill_map(obj_map, s, slab);
for_each_object(p, s, addr, slab->objects) {
u8 val = test_bit(__obj_to_index(s, addr, p), obj_map) ?
SLUB_RED_INACTIVE : SLUB_RED_ACTIVE;
if (!check_object(s, slab, p, val))
break;
}
}
static int validate_slab_node(struct kmem_cache *s,
struct kmem_cache_node *n, unsigned long *obj_map)
{
unsigned long count = 0;
struct slab *slab;
unsigned long flags;
spin_lock_irqsave(&n->list_lock, flags);
list_for_each_entry(slab, &n->partial, slab_list) {
validate_slab(s, slab, obj_map);
count++;
}
if (count != n->nr_partial) {
pr_err("SLUB %s: %ld partial slabs counted but counter=%ld\n",
s->name, count, n->nr_partial);
slab_add_kunit_errors();
}
if (!(s->flags & SLAB_STORE_USER))
goto out;
list_for_each_entry(slab, &n->full, slab_list) {
validate_slab(s, slab, obj_map);
count++;
}
if (count != node_nr_slabs(n)) {
pr_err("SLUB: %s %ld slabs counted but counter=%ld\n",
s->name, count, node_nr_slabs(n));
slab_add_kunit_errors();
}
out:
spin_unlock_irqrestore(&n->list_lock, flags);
return count;
}
long validate_slab_cache(struct kmem_cache *s)
{
int node;
unsigned long count = 0;
struct kmem_cache_node *n;
unsigned long *obj_map;
obj_map = bitmap_alloc(oo_objects(s->oo), GFP_KERNEL);
if (!obj_map)
return -ENOMEM;
flush_all(s);
for_each_kmem_cache_node(s, node, n)
count += validate_slab_node(s, n, obj_map);
bitmap_free(obj_map);
return count;
}
EXPORT_SYMBOL(validate_slab_cache);
#ifdef CONFIG_DEBUG_FS
/*
* Generate lists of code addresses where slabcache objects are allocated
* and freed.
*/
struct location {
depot_stack_handle_t handle;
unsigned long count;
unsigned long addr;
unsigned long waste;
long long sum_time;
long min_time;
long max_time;
long min_pid;
long max_pid;
DECLARE_BITMAP(cpus, NR_CPUS);
nodemask_t nodes;
};
struct loc_track {
unsigned long max;
unsigned long count;
struct location *loc;
loff_t idx;
};
static struct dentry *slab_debugfs_root;
static void free_loc_track(struct loc_track *t)
{
if (t->max)
free_pages((unsigned long)t->loc,
get_order(sizeof(struct location) * t->max));
}
static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
{
struct location *l;
int order;
order = get_order(sizeof(struct location) * max);
l = (void *)__get_free_pages(flags, order);
if (!l)
return 0;
if (t->count) {
memcpy(l, t->loc, sizeof(struct location) * t->count);
free_loc_track(t);
}
t->max = max;
t->loc = l;
return 1;
}
static int add_location(struct loc_track *t, struct kmem_cache *s,
const struct track *track,
unsigned int orig_size)
{
long start, end, pos;
struct location *l;
unsigned long caddr, chandle, cwaste;
unsigned long age = jiffies - track->when;
depot_stack_handle_t handle = 0;
unsigned int waste = s->object_size - orig_size;
#ifdef CONFIG_STACKDEPOT
handle = READ_ONCE(track->handle);
#endif
start = -1;
end = t->count;
for ( ; ; ) {
pos = start + (end - start + 1) / 2;
/*
* There is nothing at "end". If we end up there
* we need to add something to before end.
*/
if (pos == end)
break;
l = &t->loc[pos];
caddr = l->addr;
chandle = l->handle;
cwaste = l->waste;
if ((track->addr == caddr) && (handle == chandle) &&
(waste == cwaste)) {
l->count++;
if (track->when) {
l->sum_time += age;
if (age < l->min_time)
l->min_time = age;
if (age > l->max_time)
l->max_time = age;
if (track->pid < l->min_pid)
l->min_pid = track->pid;
if (track->pid > l->max_pid)
l->max_pid = track->pid;
cpumask_set_cpu(track->cpu,
to_cpumask(l->cpus));
}
node_set(page_to_nid(virt_to_page(track)), l->nodes);
return 1;
}
if (track->addr < caddr)
end = pos;
else if (track->addr == caddr && handle < chandle)
end = pos;
else if (track->addr == caddr && handle == chandle &&
waste < cwaste)
end = pos;
else
start = pos;
}
/*
* Not found. Insert new tracking element.
*/
if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
return 0;
l = t->loc + pos;
if (pos < t->count)
memmove(l + 1, l,
(t->count - pos) * sizeof(struct location));
t->count++;
l->count = 1;
l->addr = track->addr;
l->sum_time = age;
l->min_time = age;
l->max_time = age;
l->min_pid = track->pid;
l->max_pid = track->pid;
l->handle = handle;
l->waste = waste;
cpumask_clear(to_cpumask(l->cpus));
cpumask_set_cpu(track->cpu, to_cpumask(l->cpus));
nodes_clear(l->nodes);
node_set(page_to_nid(virt_to_page(track)), l->nodes);
return 1;
}
static void process_slab(struct loc_track *t, struct kmem_cache *s,
struct slab *slab, enum track_item alloc,
unsigned long *obj_map)
{
void *addr = slab_address(slab);
bool is_alloc = (alloc == TRACK_ALLOC);
void *p;
__fill_map(obj_map, s, slab);
for_each_object(p, s, addr, slab->objects)
if (!test_bit(__obj_to_index(s, addr, p), obj_map))
add_location(t, s, get_track(s, p, alloc),
is_alloc ? get_orig_size(s, p) :
s->object_size);
}
#endif /* CONFIG_DEBUG_FS */
#endif /* CONFIG_SLUB_DEBUG */
#ifdef SLAB_SUPPORTS_SYSFS
enum slab_stat_type {
SL_ALL, /* All slabs */
SL_PARTIAL, /* Only partially allocated slabs */
SL_CPU, /* Only slabs used for cpu caches */
SL_OBJECTS, /* Determine allocated objects not slabs */
SL_TOTAL /* Determine object capacity not slabs */
};
#define SO_ALL (1 << SL_ALL)
#define SO_PARTIAL (1 << SL_PARTIAL)
#define SO_CPU (1 << SL_CPU)
#define SO_OBJECTS (1 << SL_OBJECTS)
#define SO_TOTAL (1 << SL_TOTAL)
static ssize_t show_slab_objects(struct kmem_cache *s,
char *buf, unsigned long flags)
{
unsigned long total = 0;
int node;
int x;
unsigned long *nodes;
int len = 0;
nodes = kcalloc(nr_node_ids, sizeof(unsigned long), GFP_KERNEL);
if (!nodes)
return -ENOMEM;
if (flags & SO_CPU) {
int cpu;
for_each_possible_cpu(cpu) {
struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab,
cpu);
int node;
struct slab *slab;
slab = READ_ONCE(c->slab);
if (!slab)
continue;
node = slab_nid(slab);
if (flags & SO_TOTAL)
x = slab->objects;
else if (flags & SO_OBJECTS)
x = slab->inuse;
else
x = 1;
total += x;
nodes[node] += x;
#ifdef CONFIG_SLUB_CPU_PARTIAL
slab = slub_percpu_partial_read_once(c);
if (slab) {
node = slab_nid(slab);
if (flags & SO_TOTAL)
WARN_ON_ONCE(1);
else if (flags & SO_OBJECTS)
WARN_ON_ONCE(1);
else
x = slab->slabs;
total += x;
nodes[node] += x;
}
#endif
}
}
/*
* It is impossible to take "mem_hotplug_lock" here with "kernfs_mutex"
* already held which will conflict with an existing lock order:
*
* mem_hotplug_lock->slab_mutex->kernfs_mutex
*
* We don't really need mem_hotplug_lock (to hold off
* slab_mem_going_offline_callback) here because slab's memory hot
* unplug code doesn't destroy the kmem_cache->node[] data.
*/
#ifdef CONFIG_SLUB_DEBUG
if (flags & SO_ALL) {
struct kmem_cache_node *n;
for_each_kmem_cache_node(s, node, n) {
if (flags & SO_TOTAL)
x = node_nr_objs(n);
else if (flags & SO_OBJECTS)
x = node_nr_objs(n) - count_partial(n, count_free);
else
x = node_nr_slabs(n);
total += x;
nodes[node] += x;
}
} else
#endif
if (flags & SO_PARTIAL) {
struct kmem_cache_node *n;
for_each_kmem_cache_node(s, node, n) {
if (flags & SO_TOTAL)
x = count_partial(n, count_total);
else if (flags & SO_OBJECTS)
x = count_partial(n, count_inuse);
else
x = n->nr_partial;
total += x;
nodes[node] += x;
}
}
len += sysfs_emit_at(buf, len, "%lu", total);
#ifdef CONFIG_NUMA
for (node = 0; node < nr_node_ids; node++) {
if (nodes[node])
len += sysfs_emit_at(buf, len, " N%d=%lu",
node, nodes[node]);
}
#endif
len += sysfs_emit_at(buf, len, "\n");
kfree(nodes);
return len;
}
#define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
#define to_slab(n) container_of(n, struct kmem_cache, kobj)
struct slab_attribute {
struct attribute attr;
ssize_t (*show)(struct kmem_cache *s, char *buf);
ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
};
#define SLAB_ATTR_RO(_name) \
static struct slab_attribute _name##_attr = __ATTR_RO_MODE(_name, 0400)
#define SLAB_ATTR(_name) \
static struct slab_attribute _name##_attr = __ATTR_RW_MODE(_name, 0600)
static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
{
return sysfs_emit(buf, "%u\n", s->size);
}
SLAB_ATTR_RO(slab_size);
static ssize_t align_show(struct kmem_cache *s, char *buf)
{
return sysfs_emit(buf, "%u\n", s->align);
}
SLAB_ATTR_RO(align);
static ssize_t object_size_show(struct kmem_cache *s, char *buf)
{
return sysfs_emit(buf, "%u\n", s->object_size);
}
SLAB_ATTR_RO(object_size);
static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
{
return sysfs_emit(buf, "%u\n", oo_objects(s->oo));
}
SLAB_ATTR_RO(objs_per_slab);
static ssize_t order_show(struct kmem_cache *s, char *buf)
{
return sysfs_emit(buf, "%u\n", oo_order(s->oo));
}
SLAB_ATTR_RO(order);
static ssize_t min_partial_show(struct kmem_cache *s, char *buf)
{
return sysfs_emit(buf, "%lu\n", s->min_partial);
}
static ssize_t min_partial_store(struct kmem_cache *s, const char *buf,
size_t length)
{
unsigned long min;
int err;
err = kstrtoul(buf, 10, &min);
if (err)
return err;
s->min_partial = min;
return length;
}
SLAB_ATTR(min_partial);
static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf)
{
unsigned int nr_partial = 0;
#ifdef CONFIG_SLUB_CPU_PARTIAL
nr_partial = s->cpu_partial;
#endif
return sysfs_emit(buf, "%u\n", nr_partial);
}
static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf,
size_t length)
{
unsigned int objects;
int err;
err = kstrtouint(buf, 10, &objects);
if (err)
return err;
if (objects && !kmem_cache_has_cpu_partial(s))
return -EINVAL;
slub_set_cpu_partial(s, objects);
flush_all(s);
return length;
}
SLAB_ATTR(cpu_partial);
static ssize_t ctor_show(struct kmem_cache *s, char *buf)
{
if (!s->ctor)
return 0;
return sysfs_emit(buf, "%pS\n", s->ctor);
}
SLAB_ATTR_RO(ctor);
static ssize_t aliases_show(struct kmem_cache *s, char *buf)
{
return sysfs_emit(buf, "%d\n", s->refcount < 0 ? 0 : s->refcount - 1);
}
SLAB_ATTR_RO(aliases);
static ssize_t partial_show(struct kmem_cache *s, char *buf)
{
return show_slab_objects(s, buf, SO_PARTIAL);
}
SLAB_ATTR_RO(partial);
static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
{
return show_slab_objects(s, buf, SO_CPU);
}
SLAB_ATTR_RO(cpu_slabs);
static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
{
return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS);
}
SLAB_ATTR_RO(objects_partial);
static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
{
int objects = 0;
int slabs = 0;
int cpu __maybe_unused;
int len = 0;
#ifdef CONFIG_SLUB_CPU_PARTIAL
for_each_online_cpu(cpu) {
struct slab *slab;
slab = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
if (slab)
slabs += slab->slabs;
}
#endif
/* Approximate half-full slabs, see slub_set_cpu_partial() */
objects = (slabs * oo_objects(s->oo)) / 2;
len += sysfs_emit_at(buf, len, "%d(%d)", objects, slabs);
#ifdef CONFIG_SLUB_CPU_PARTIAL
for_each_online_cpu(cpu) {
struct slab *slab;
slab = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
if (slab) {
slabs = READ_ONCE(slab->slabs);
objects = (slabs * oo_objects(s->oo)) / 2;
len += sysfs_emit_at(buf, len, " C%d=%d(%d)",
cpu, objects, slabs);
}
}
#endif
len += sysfs_emit_at(buf, len, "\n");
return len;
}
SLAB_ATTR_RO(slabs_cpu_partial);
static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
{
return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
}
SLAB_ATTR_RO(reclaim_account);
static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
{
return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
}
SLAB_ATTR_RO(hwcache_align);
#ifdef CONFIG_ZONE_DMA
static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
{
return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
}
SLAB_ATTR_RO(cache_dma);
#endif
#ifdef CONFIG_HARDENED_USERCOPY
static ssize_t usersize_show(struct kmem_cache *s, char *buf)
{
return sysfs_emit(buf, "%u\n", s->usersize);
}
SLAB_ATTR_RO(usersize);
#endif
static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
{
return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_TYPESAFE_BY_RCU));
}
SLAB_ATTR_RO(destroy_by_rcu);
#ifdef CONFIG_SLUB_DEBUG
static ssize_t slabs_show(struct kmem_cache *s, char *buf)
{
return show_slab_objects(s, buf, SO_ALL);
}
SLAB_ATTR_RO(slabs);
static ssize_t total_objects_show(struct kmem_cache *s, char *buf)
{
return show_slab_objects(s, buf, SO_ALL|SO_TOTAL);
}
SLAB_ATTR_RO(total_objects);
static ssize_t objects_show(struct kmem_cache *s, char *buf)
{
return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS);
}
SLAB_ATTR_RO(objects);
static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
{
return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_CONSISTENCY_CHECKS));
}
SLAB_ATTR_RO(sanity_checks);
static ssize_t trace_show(struct kmem_cache *s, char *buf)
{
return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_TRACE));
}
SLAB_ATTR_RO(trace);
static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
{
return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
}
SLAB_ATTR_RO(red_zone);
static ssize_t poison_show(struct kmem_cache *s, char *buf)
{
return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_POISON));
}
SLAB_ATTR_RO(poison);
static ssize_t store_user_show(struct kmem_cache *s, char *buf)
{
return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
}
SLAB_ATTR_RO(store_user);
static ssize_t validate_show(struct kmem_cache *s, char *buf)
{
return 0;
}
static ssize_t validate_store(struct kmem_cache *s,
const char *buf, size_t length)
{
int ret = -EINVAL;
if (buf[0] == '1' && kmem_cache_debug(s)) {
ret = validate_slab_cache(s);
if (ret >= 0)
ret = length;
}
return ret;
}
SLAB_ATTR(validate);
#endif /* CONFIG_SLUB_DEBUG */
#ifdef CONFIG_FAILSLAB
static ssize_t failslab_show(struct kmem_cache *s, char *buf)
{
return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB));
}
static ssize_t failslab_store(struct kmem_cache *s, const char *buf,
size_t length)
{
if (s->refcount > 1)
return -EINVAL;
if (buf[0] == '1')
WRITE_ONCE(s->flags, s->flags | SLAB_FAILSLAB);
else
WRITE_ONCE(s->flags, s->flags & ~SLAB_FAILSLAB);
return length;
}
SLAB_ATTR(failslab);
#endif
static ssize_t shrink_show(struct kmem_cache *s, char *buf)
{
return 0;
}
static ssize_t shrink_store(struct kmem_cache *s,
const char *buf, size_t length)
{
if (buf[0] == '1')
kmem_cache_shrink(s);
else
return -EINVAL;
return length;
}
SLAB_ATTR(shrink);
#ifdef CONFIG_NUMA
static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
{
return sysfs_emit(buf, "%u\n", s->remote_node_defrag_ratio / 10);
}
static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
const char *buf, size_t length)
{
unsigned int ratio;
int err;
err = kstrtouint(buf, 10, &ratio);
if (err)
return err;
if (ratio > 100)
return -ERANGE;
s->remote_node_defrag_ratio = ratio * 10;
return length;
}
SLAB_ATTR(remote_node_defrag_ratio);
#endif
#ifdef CONFIG_SLUB_STATS
static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
{
unsigned long sum = 0;
int cpu;
int len = 0;
int *data = kmalloc_array(nr_cpu_ids, sizeof(int), GFP_KERNEL);
if (!data)
return -ENOMEM;
for_each_online_cpu(cpu) {
unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si];
data[cpu] = x;
sum += x;
}
len += sysfs_emit_at(buf, len, "%lu", sum);
#ifdef CONFIG_SMP
for_each_online_cpu(cpu) {
if (data[cpu])
len += sysfs_emit_at(buf, len, " C%d=%u",
cpu, data[cpu]);
}
#endif
kfree(data);
len += sysfs_emit_at(buf, len, "\n");
return len;
}
static void clear_stat(struct kmem_cache *s, enum stat_item si)
{
int cpu;
for_each_online_cpu(cpu)
per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0;
}
#define STAT_ATTR(si, text) \
static ssize_t text##_show(struct kmem_cache *s, char *buf) \
{ \
return show_stat(s, buf, si); \
} \
static ssize_t text##_store(struct kmem_cache *s, \
const char *buf, size_t length) \
{ \
if (buf[0] != '0') \
return -EINVAL; \
clear_stat(s, si); \
return length; \
} \
SLAB_ATTR(text); \
STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
STAT_ATTR(FREE_FASTPATH, free_fastpath);
STAT_ATTR(FREE_SLOWPATH, free_slowpath);
STAT_ATTR(FREE_FROZEN, free_frozen);
STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
STAT_ATTR(ALLOC_SLAB, alloc_slab);
STAT_ATTR(ALLOC_REFILL, alloc_refill);
STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch);
STAT_ATTR(FREE_SLAB, free_slab);
STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass);
STAT_ATTR(ORDER_FALLBACK, order_fallback);
STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc);
STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free);
STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node);
STAT_ATTR(CPU_PARTIAL_DRAIN, cpu_partial_drain);
#endif /* CONFIG_SLUB_STATS */
#ifdef CONFIG_KFENCE
static ssize_t skip_kfence_show(struct kmem_cache *s, char *buf)
{
return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_SKIP_KFENCE));
}
static ssize_t skip_kfence_store(struct kmem_cache *s,
const char *buf, size_t length)
{
int ret = length;
if (buf[0] == '0')
s->flags &= ~SLAB_SKIP_KFENCE;
else if (buf[0] == '1')
s->flags |= SLAB_SKIP_KFENCE;
else
ret = -EINVAL;
return ret;
}
SLAB_ATTR(skip_kfence);
#endif
static struct attribute *slab_attrs[] = {
&slab_size_attr.attr,
&object_size_attr.attr,
&objs_per_slab_attr.attr,
&order_attr.attr,
&min_partial_attr.attr,
&cpu_partial_attr.attr,
&objects_partial_attr.attr,
&partial_attr.attr,
&cpu_slabs_attr.attr,
&ctor_attr.attr,
&aliases_attr.attr,
&align_attr.attr,
&hwcache_align_attr.attr,
&reclaim_account_attr.attr,
&destroy_by_rcu_attr.attr,
&shrink_attr.attr,
&slabs_cpu_partial_attr.attr,
#ifdef CONFIG_SLUB_DEBUG
&total_objects_attr.attr,
&objects_attr.attr,
&slabs_attr.attr,
&sanity_checks_attr.attr,
&trace_attr.attr,
&red_zone_attr.attr,
&poison_attr.attr,
&store_user_attr.attr,
&validate_attr.attr,
#endif
#ifdef CONFIG_ZONE_DMA
&cache_dma_attr.attr,
#endif
#ifdef CONFIG_NUMA
&remote_node_defrag_ratio_attr.attr,
#endif
#ifdef CONFIG_SLUB_STATS
&alloc_fastpath_attr.attr,
&alloc_slowpath_attr.attr,
&free_fastpath_attr.attr,
&free_slowpath_attr.attr,
&free_frozen_attr.attr,
&free_add_partial_attr.attr,
&free_remove_partial_attr.attr,
&alloc_from_partial_attr.attr,
&alloc_slab_attr.attr,
&alloc_refill_attr.attr,
&alloc_node_mismatch_attr.attr,
&free_slab_attr.attr,
&cpuslab_flush_attr.attr,
&deactivate_full_attr.attr,
&deactivate_empty_attr.attr,
&deactivate_to_head_attr.attr,
&deactivate_to_tail_attr.attr,
&deactivate_remote_frees_attr.attr,
&deactivate_bypass_attr.attr,
&order_fallback_attr.attr,
&cmpxchg_double_fail_attr.attr,
&cmpxchg_double_cpu_fail_attr.attr,
&cpu_partial_alloc_attr.attr,
&cpu_partial_free_attr.attr,
&cpu_partial_node_attr.attr,
&cpu_partial_drain_attr.attr,
#endif
#ifdef CONFIG_FAILSLAB
&failslab_attr.attr,
#endif
#ifdef CONFIG_HARDENED_USERCOPY
&usersize_attr.attr,
#endif
#ifdef CONFIG_KFENCE
&skip_kfence_attr.attr,
#endif
NULL
};
static const struct attribute_group slab_attr_group = {
.attrs = slab_attrs,
};
static ssize_t slab_attr_show(struct kobject *kobj,
struct attribute *attr,
char *buf)
{
struct slab_attribute *attribute;
struct kmem_cache *s;
attribute = to_slab_attr(attr);
s = to_slab(kobj);
if (!attribute->show)
return -EIO;
return attribute->show(s, buf);
}
static ssize_t slab_attr_store(struct kobject *kobj,
struct attribute *attr,
const char *buf, size_t len)
{
struct slab_attribute *attribute;
struct kmem_cache *s;
attribute = to_slab_attr(attr);
s = to_slab(kobj);
if (!attribute->store)
return -EIO;
return attribute->store(s, buf, len);
}
static void kmem_cache_release(struct kobject *k)
{
slab_kmem_cache_release(to_slab(k));
}
static const struct sysfs_ops slab_sysfs_ops = {
.show = slab_attr_show,
.store = slab_attr_store,
};
static const struct kobj_type slab_ktype = {
.sysfs_ops = &slab_sysfs_ops,
.release = kmem_cache_release,
};
static struct kset *slab_kset;
static inline struct kset *cache_kset(struct kmem_cache *s)
{
return slab_kset;
}
#define ID_STR_LENGTH 32
/* Create a unique string id for a slab cache:
*
* Format :[flags-]size
*/
static char *create_unique_id(struct kmem_cache *s)
{
char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
char *p = name;
if (!name)
return ERR_PTR(-ENOMEM);
*p++ = ':';
/*
* First flags affecting slabcache operations. We will only
* get here for aliasable slabs so we do not need to support
* too many flags. The flags here must cover all flags that
* are matched during merging to guarantee that the id is
* unique.
*/
if (s->flags & SLAB_CACHE_DMA)
*p++ = 'd';
if (s->flags & SLAB_CACHE_DMA32)
*p++ = 'D';
if (s->flags & SLAB_RECLAIM_ACCOUNT)
*p++ = 'a';
if (s->flags & SLAB_CONSISTENCY_CHECKS)
*p++ = 'F';
if (s->flags & SLAB_ACCOUNT)
*p++ = 'A';
if (p != name + 1)
*p++ = '-';
p += snprintf(p, ID_STR_LENGTH - (p - name), "%07u", s->size);
if (WARN_ON(p > name + ID_STR_LENGTH - 1)) {
kfree(name);
return ERR_PTR(-EINVAL);
}
kmsan_unpoison_memory(name, p - name);
return name;
}
static int sysfs_slab_add(struct kmem_cache *s)
{
int err;
const char *name;
struct kset *kset = cache_kset(s);
int unmergeable = slab_unmergeable(s);
if (!unmergeable && disable_higher_order_debug &&
(slub_debug & DEBUG_METADATA_FLAGS))
unmergeable = 1;
if (unmergeable) {
/*
* Slabcache can never be merged so we can use the name proper.
* This is typically the case for debug situations. In that
* case we can catch duplicate names easily.
*/
sysfs_remove_link(&slab_kset->kobj, s->name);
name = s->name;
} else {
/*
* Create a unique name for the slab as a target
* for the symlinks.
*/
name = create_unique_id(s);
if (IS_ERR(name))
return PTR_ERR(name);
}
s->kobj.kset = kset;
err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, "%s", name);
if (err)
goto out;
err = sysfs_create_group(&s->kobj, &slab_attr_group);
if (err)
goto out_del_kobj;
if (!unmergeable) {
/* Setup first alias */
sysfs_slab_alias(s, s->name);
}
out:
if (!unmergeable)
kfree(name);
return err;
out_del_kobj:
kobject_del(&s->kobj);
goto out;
}
void sysfs_slab_unlink(struct kmem_cache *s)
{
if (slab_state >= FULL)
kobject_del(&s->kobj);
}
void sysfs_slab_release(struct kmem_cache *s)
{
if (slab_state >= FULL)
kobject_put(&s->kobj);
}
/*
* Need to buffer aliases during bootup until sysfs becomes
* available lest we lose that information.
*/
struct saved_alias {
struct kmem_cache *s;
const char *name;
struct saved_alias *next;
};
static struct saved_alias *alias_list;
static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
{
struct saved_alias *al;
if (slab_state == FULL) {
/*
* If we have a leftover link then remove it.
*/
sysfs_remove_link(&slab_kset->kobj, name);
return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
}
al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
if (!al)
return -ENOMEM;
al->s = s;
al->name = name;
al->next = alias_list;
alias_list = al;
kmsan_unpoison_memory(al, sizeof(*al));
return 0;
}
static int __init slab_sysfs_init(void)
{
struct kmem_cache *s;
int err;
mutex_lock(&slab_mutex);
slab_kset = kset_create_and_add("slab", NULL, kernel_kobj);
if (!slab_kset) {
mutex_unlock(&slab_mutex);
pr_err("Cannot register slab subsystem.\n");
return -ENOMEM;
}
slab_state = FULL;
list_for_each_entry(s, &slab_caches, list) {
err = sysfs_slab_add(s);
if (err)
pr_err("SLUB: Unable to add boot slab %s to sysfs\n",
s->name);
}
while (alias_list) {
struct saved_alias *al = alias_list;
alias_list = alias_list->next;
err = sysfs_slab_alias(al->s, al->name);
if (err)
pr_err("SLUB: Unable to add boot slab alias %s to sysfs\n",
al->name);
kfree(al);
}
mutex_unlock(&slab_mutex);
return 0;
}
late_initcall(slab_sysfs_init);
#endif /* SLAB_SUPPORTS_SYSFS */
#if defined(CONFIG_SLUB_DEBUG) && defined(CONFIG_DEBUG_FS)
static int slab_debugfs_show(struct seq_file *seq, void *v)
{
struct loc_track *t = seq->private;
struct location *l;
unsigned long idx;
idx = (unsigned long) t->idx;
if (idx < t->count) {
l = &t->loc[idx];
seq_printf(seq, "%7ld ", l->count);
if (l->addr)
seq_printf(seq, "%pS", (void *)l->addr);
else
seq_puts(seq, "<not-available>");
if (l->waste)
seq_printf(seq, " waste=%lu/%lu",
l->count * l->waste, l->waste);
if (l->sum_time != l->min_time) {
seq_printf(seq, " age=%ld/%llu/%ld",
l->min_time, div_u64(l->sum_time, l->count),
l->max_time);
} else
seq_printf(seq, " age=%ld", l->min_time);
if (l->min_pid != l->max_pid)
seq_printf(seq, " pid=%ld-%ld", l->min_pid, l->max_pid);
else
seq_printf(seq, " pid=%ld",
l->min_pid);
if (num_online_cpus() > 1 && !cpumask_empty(to_cpumask(l->cpus)))
seq_printf(seq, " cpus=%*pbl",
cpumask_pr_args(to_cpumask(l->cpus)));
if (nr_online_nodes > 1 && !nodes_empty(l->nodes))
seq_printf(seq, " nodes=%*pbl",
nodemask_pr_args(&l->nodes));
#ifdef CONFIG_STACKDEPOT
{
depot_stack_handle_t handle;
unsigned long *entries;
unsigned int nr_entries, j;
handle = READ_ONCE(l->handle);
if (handle) {
nr_entries = stack_depot_fetch(handle, &entries);
seq_puts(seq, "\n");
for (j = 0; j < nr_entries; j++)
seq_printf(seq, " %pS\n", (void *)entries[j]);
}
}
#endif
seq_puts(seq, "\n");
}
if (!idx && !t->count)
seq_puts(seq, "No data\n");
return 0;
}
static void slab_debugfs_stop(struct seq_file *seq, void *v)
{
}
static void *slab_debugfs_next(struct seq_file *seq, void *v, loff_t *ppos)
{
struct loc_track *t = seq->private;
t->idx = ++(*ppos);
if (*ppos <= t->count)
return ppos;
return NULL;
}
static int cmp_loc_by_count(const void *a, const void *b, const void *data)
{
struct location *loc1 = (struct location *)a;
struct location *loc2 = (struct location *)b;
if (loc1->count > loc2->count)
return -1;
else
return 1;
}
static void *slab_debugfs_start(struct seq_file *seq, loff_t *ppos)
{
struct loc_track *t = seq->private;
t->idx = *ppos;
return ppos;
}
static const struct seq_operations slab_debugfs_sops = {
.start = slab_debugfs_start,
.next = slab_debugfs_next,
.stop = slab_debugfs_stop,
.show = slab_debugfs_show,
};
static int slab_debug_trace_open(struct inode *inode, struct file *filep)
{
struct kmem_cache_node *n;
enum track_item alloc;
int node;
struct loc_track *t = __seq_open_private(filep, &slab_debugfs_sops,
sizeof(struct loc_track));
struct kmem_cache *s = file_inode(filep)->i_private;
unsigned long *obj_map;
if (!t)
return -ENOMEM;
obj_map = bitmap_alloc(oo_objects(s->oo), GFP_KERNEL);
if (!obj_map) {
seq_release_private(inode, filep);
return -ENOMEM;
}
if (strcmp(filep->f_path.dentry->d_name.name, "alloc_traces") == 0)
alloc = TRACK_ALLOC;
else
alloc = TRACK_FREE;
if (!alloc_loc_track(t, PAGE_SIZE / sizeof(struct location), GFP_KERNEL)) {
bitmap_free(obj_map);
seq_release_private(inode, filep);
return -ENOMEM;
}
for_each_kmem_cache_node(s, node, n) {
unsigned long flags;
struct slab *slab;
if (!node_nr_slabs(n))
continue;
spin_lock_irqsave(&n->list_lock, flags);
list_for_each_entry(slab, &n->partial, slab_list)
process_slab(t, s, slab, alloc, obj_map);
list_for_each_entry(slab, &n->full, slab_list)
process_slab(t, s, slab, alloc, obj_map);
spin_unlock_irqrestore(&n->list_lock, flags);
}
/* Sort locations by count */
sort_r(t->loc, t->count, sizeof(struct location),
cmp_loc_by_count, NULL, NULL);
bitmap_free(obj_map);
return 0;
}
static int slab_debug_trace_release(struct inode *inode, struct file *file)
{
struct seq_file *seq = file->private_data;
struct loc_track *t = seq->private;
free_loc_track(t);
return seq_release_private(inode, file);
}
static const struct file_operations slab_debugfs_fops = {
.open = slab_debug_trace_open,
.read = seq_read,
.llseek = seq_lseek,
.release = slab_debug_trace_release,
};
static void debugfs_slab_add(struct kmem_cache *s)
{
struct dentry *slab_cache_dir;
if (unlikely(!slab_debugfs_root))
return;
slab_cache_dir = debugfs_create_dir(s->name, slab_debugfs_root);
debugfs_create_file("alloc_traces", 0400,
slab_cache_dir, s, &slab_debugfs_fops);
debugfs_create_file("free_traces", 0400,
slab_cache_dir, s, &slab_debugfs_fops);
}
void debugfs_slab_release(struct kmem_cache *s)
{
debugfs_lookup_and_remove(s->name, slab_debugfs_root);
}
static int __init slab_debugfs_init(void)
{
struct kmem_cache *s;
slab_debugfs_root = debugfs_create_dir("slab", NULL);
list_for_each_entry(s, &slab_caches, list)
if (s->flags & SLAB_STORE_USER)
debugfs_slab_add(s);
return 0;
}
__initcall(slab_debugfs_init);
#endif
/*
* The /proc/slabinfo ABI
*/
#ifdef CONFIG_SLUB_DEBUG
void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo)
{
unsigned long nr_slabs = 0;
unsigned long nr_objs = 0;
unsigned long nr_free = 0;
int node;
struct kmem_cache_node *n;
for_each_kmem_cache_node(s, node, n) {
nr_slabs += node_nr_slabs(n);
nr_objs += node_nr_objs(n);
nr_free += count_partial(n, count_free);
}
sinfo->active_objs = nr_objs - nr_free;
sinfo->num_objs = nr_objs;
sinfo->active_slabs = nr_slabs;
sinfo->num_slabs = nr_slabs;
sinfo->objects_per_slab = oo_objects(s->oo);
sinfo->cache_order = oo_order(s->oo);
}
void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s)
{
}
ssize_t slabinfo_write(struct file *file, const char __user *buffer,
size_t count, loff_t *ppos)
{
return -EIO;
}
#endif /* CONFIG_SLUB_DEBUG */
| linux-master | mm/slub.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/slab.h>
#include <linux/lockdep.h>
#include <linux/sysfs.h>
#include <linux/kobject.h>
#include <linux/memory.h>
#include <linux/memory-tiers.h>
#include "internal.h"
struct memory_tier {
/* hierarchy of memory tiers */
struct list_head list;
/* list of all memory types part of this tier */
struct list_head memory_types;
/*
* start value of abstract distance. memory tier maps
* an abstract distance range,
* adistance_start .. adistance_start + MEMTIER_CHUNK_SIZE
*/
int adistance_start;
struct device dev;
/* All the nodes that are part of all the lower memory tiers. */
nodemask_t lower_tier_mask;
};
struct demotion_nodes {
nodemask_t preferred;
};
struct node_memory_type_map {
struct memory_dev_type *memtype;
int map_count;
};
static DEFINE_MUTEX(memory_tier_lock);
static LIST_HEAD(memory_tiers);
static struct node_memory_type_map node_memory_types[MAX_NUMNODES];
static struct memory_dev_type *default_dram_type;
static struct bus_type memory_tier_subsys = {
.name = "memory_tiering",
.dev_name = "memory_tier",
};
#ifdef CONFIG_MIGRATION
static int top_tier_adistance;
/*
* node_demotion[] examples:
*
* Example 1:
*
* Node 0 & 1 are CPU + DRAM nodes, node 2 & 3 are PMEM nodes.
*
* node distances:
* node 0 1 2 3
* 0 10 20 30 40
* 1 20 10 40 30
* 2 30 40 10 40
* 3 40 30 40 10
*
* memory_tiers0 = 0-1
* memory_tiers1 = 2-3
*
* node_demotion[0].preferred = 2
* node_demotion[1].preferred = 3
* node_demotion[2].preferred = <empty>
* node_demotion[3].preferred = <empty>
*
* Example 2:
*
* Node 0 & 1 are CPU + DRAM nodes, node 2 is memory-only DRAM node.
*
* node distances:
* node 0 1 2
* 0 10 20 30
* 1 20 10 30
* 2 30 30 10
*
* memory_tiers0 = 0-2
*
* node_demotion[0].preferred = <empty>
* node_demotion[1].preferred = <empty>
* node_demotion[2].preferred = <empty>
*
* Example 3:
*
* Node 0 is CPU + DRAM nodes, Node 1 is HBM node, node 2 is PMEM node.
*
* node distances:
* node 0 1 2
* 0 10 20 30
* 1 20 10 40
* 2 30 40 10
*
* memory_tiers0 = 1
* memory_tiers1 = 0
* memory_tiers2 = 2
*
* node_demotion[0].preferred = 2
* node_demotion[1].preferred = 0
* node_demotion[2].preferred = <empty>
*
*/
static struct demotion_nodes *node_demotion __read_mostly;
#endif /* CONFIG_MIGRATION */
static inline struct memory_tier *to_memory_tier(struct device *device)
{
return container_of(device, struct memory_tier, dev);
}
static __always_inline nodemask_t get_memtier_nodemask(struct memory_tier *memtier)
{
nodemask_t nodes = NODE_MASK_NONE;
struct memory_dev_type *memtype;
list_for_each_entry(memtype, &memtier->memory_types, tier_sibiling)
nodes_or(nodes, nodes, memtype->nodes);
return nodes;
}
static void memory_tier_device_release(struct device *dev)
{
struct memory_tier *tier = to_memory_tier(dev);
/*
* synchronize_rcu in clear_node_memory_tier makes sure
* we don't have rcu access to this memory tier.
*/
kfree(tier);
}
static ssize_t nodelist_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
int ret;
nodemask_t nmask;
mutex_lock(&memory_tier_lock);
nmask = get_memtier_nodemask(to_memory_tier(dev));
ret = sysfs_emit(buf, "%*pbl\n", nodemask_pr_args(&nmask));
mutex_unlock(&memory_tier_lock);
return ret;
}
static DEVICE_ATTR_RO(nodelist);
static struct attribute *memtier_dev_attrs[] = {
&dev_attr_nodelist.attr,
NULL
};
static const struct attribute_group memtier_dev_group = {
.attrs = memtier_dev_attrs,
};
static const struct attribute_group *memtier_dev_groups[] = {
&memtier_dev_group,
NULL
};
static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memtype)
{
int ret;
bool found_slot = false;
struct memory_tier *memtier, *new_memtier;
int adistance = memtype->adistance;
unsigned int memtier_adistance_chunk_size = MEMTIER_CHUNK_SIZE;
lockdep_assert_held_once(&memory_tier_lock);
adistance = round_down(adistance, memtier_adistance_chunk_size);
/*
* If the memtype is already part of a memory tier,
* just return that.
*/
if (!list_empty(&memtype->tier_sibiling)) {
list_for_each_entry(memtier, &memory_tiers, list) {
if (adistance == memtier->adistance_start)
return memtier;
}
WARN_ON(1);
return ERR_PTR(-EINVAL);
}
list_for_each_entry(memtier, &memory_tiers, list) {
if (adistance == memtier->adistance_start) {
goto link_memtype;
} else if (adistance < memtier->adistance_start) {
found_slot = true;
break;
}
}
new_memtier = kzalloc(sizeof(struct memory_tier), GFP_KERNEL);
if (!new_memtier)
return ERR_PTR(-ENOMEM);
new_memtier->adistance_start = adistance;
INIT_LIST_HEAD(&new_memtier->list);
INIT_LIST_HEAD(&new_memtier->memory_types);
if (found_slot)
list_add_tail(&new_memtier->list, &memtier->list);
else
list_add_tail(&new_memtier->list, &memory_tiers);
new_memtier->dev.id = adistance >> MEMTIER_CHUNK_BITS;
new_memtier->dev.bus = &memory_tier_subsys;
new_memtier->dev.release = memory_tier_device_release;
new_memtier->dev.groups = memtier_dev_groups;
ret = device_register(&new_memtier->dev);
if (ret) {
list_del(&new_memtier->list);
put_device(&new_memtier->dev);
return ERR_PTR(ret);
}
memtier = new_memtier;
link_memtype:
list_add(&memtype->tier_sibiling, &memtier->memory_types);
return memtier;
}
static struct memory_tier *__node_get_memory_tier(int node)
{
pg_data_t *pgdat;
pgdat = NODE_DATA(node);
if (!pgdat)
return NULL;
/*
* Since we hold memory_tier_lock, we can avoid
* RCU read locks when accessing the details. No
* parallel updates are possible here.
*/
return rcu_dereference_check(pgdat->memtier,
lockdep_is_held(&memory_tier_lock));
}
#ifdef CONFIG_MIGRATION
bool node_is_toptier(int node)
{
bool toptier;
pg_data_t *pgdat;
struct memory_tier *memtier;
pgdat = NODE_DATA(node);
if (!pgdat)
return false;
rcu_read_lock();
memtier = rcu_dereference(pgdat->memtier);
if (!memtier) {
toptier = true;
goto out;
}
if (memtier->adistance_start <= top_tier_adistance)
toptier = true;
else
toptier = false;
out:
rcu_read_unlock();
return toptier;
}
void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets)
{
struct memory_tier *memtier;
/*
* pg_data_t.memtier updates includes a synchronize_rcu()
* which ensures that we either find NULL or a valid memtier
* in NODE_DATA. protect the access via rcu_read_lock();
*/
rcu_read_lock();
memtier = rcu_dereference(pgdat->memtier);
if (memtier)
*targets = memtier->lower_tier_mask;
else
*targets = NODE_MASK_NONE;
rcu_read_unlock();
}
/**
* next_demotion_node() - Get the next node in the demotion path
* @node: The starting node to lookup the next node
*
* Return: node id for next memory node in the demotion path hierarchy
* from @node; NUMA_NO_NODE if @node is terminal. This does not keep
* @node online or guarantee that it *continues* to be the next demotion
* target.
*/
int next_demotion_node(int node)
{
struct demotion_nodes *nd;
int target;
if (!node_demotion)
return NUMA_NO_NODE;
nd = &node_demotion[node];
/*
* node_demotion[] is updated without excluding this
* function from running.
*
* Make sure to use RCU over entire code blocks if
* node_demotion[] reads need to be consistent.
*/
rcu_read_lock();
/*
* If there are multiple target nodes, just select one
* target node randomly.
*
* In addition, we can also use round-robin to select
* target node, but we should introduce another variable
* for node_demotion[] to record last selected target node,
* that may cause cache ping-pong due to the changing of
* last target node. Or introducing per-cpu data to avoid
* caching issue, which seems more complicated. So selecting
* target node randomly seems better until now.
*/
target = node_random(&nd->preferred);
rcu_read_unlock();
return target;
}
static void disable_all_demotion_targets(void)
{
struct memory_tier *memtier;
int node;
for_each_node_state(node, N_MEMORY) {
node_demotion[node].preferred = NODE_MASK_NONE;
/*
* We are holding memory_tier_lock, it is safe
* to access pgda->memtier.
*/
memtier = __node_get_memory_tier(node);
if (memtier)
memtier->lower_tier_mask = NODE_MASK_NONE;
}
/*
* Ensure that the "disable" is visible across the system.
* Readers will see either a combination of before+disable
* state or disable+after. They will never see before and
* after state together.
*/
synchronize_rcu();
}
/*
* Find an automatic demotion target for all memory
* nodes. Failing here is OK. It might just indicate
* being at the end of a chain.
*/
static void establish_demotion_targets(void)
{
struct memory_tier *memtier;
struct demotion_nodes *nd;
int target = NUMA_NO_NODE, node;
int distance, best_distance;
nodemask_t tier_nodes, lower_tier;
lockdep_assert_held_once(&memory_tier_lock);
if (!node_demotion)
return;
disable_all_demotion_targets();
for_each_node_state(node, N_MEMORY) {
best_distance = -1;
nd = &node_demotion[node];
memtier = __node_get_memory_tier(node);
if (!memtier || list_is_last(&memtier->list, &memory_tiers))
continue;
/*
* Get the lower memtier to find the demotion node list.
*/
memtier = list_next_entry(memtier, list);
tier_nodes = get_memtier_nodemask(memtier);
/*
* find_next_best_node, use 'used' nodemask as a skip list.
* Add all memory nodes except the selected memory tier
* nodelist to skip list so that we find the best node from the
* memtier nodelist.
*/
nodes_andnot(tier_nodes, node_states[N_MEMORY], tier_nodes);
/*
* Find all the nodes in the memory tier node list of same best distance.
* add them to the preferred mask. We randomly select between nodes
* in the preferred mask when allocating pages during demotion.
*/
do {
target = find_next_best_node(node, &tier_nodes);
if (target == NUMA_NO_NODE)
break;
distance = node_distance(node, target);
if (distance == best_distance || best_distance == -1) {
best_distance = distance;
node_set(target, nd->preferred);
} else {
break;
}
} while (1);
}
/*
* Promotion is allowed from a memory tier to higher
* memory tier only if the memory tier doesn't include
* compute. We want to skip promotion from a memory tier,
* if any node that is part of the memory tier have CPUs.
* Once we detect such a memory tier, we consider that tier
* as top tiper from which promotion is not allowed.
*/
list_for_each_entry_reverse(memtier, &memory_tiers, list) {
tier_nodes = get_memtier_nodemask(memtier);
nodes_and(tier_nodes, node_states[N_CPU], tier_nodes);
if (!nodes_empty(tier_nodes)) {
/*
* abstract distance below the max value of this memtier
* is considered toptier.
*/
top_tier_adistance = memtier->adistance_start +
MEMTIER_CHUNK_SIZE - 1;
break;
}
}
/*
* Now build the lower_tier mask for each node collecting node mask from
* all memory tier below it. This allows us to fallback demotion page
* allocation to a set of nodes that is closer the above selected
* perferred node.
*/
lower_tier = node_states[N_MEMORY];
list_for_each_entry(memtier, &memory_tiers, list) {
/*
* Keep removing current tier from lower_tier nodes,
* This will remove all nodes in current and above
* memory tier from the lower_tier mask.
*/
tier_nodes = get_memtier_nodemask(memtier);
nodes_andnot(lower_tier, lower_tier, tier_nodes);
memtier->lower_tier_mask = lower_tier;
}
}
#else
static inline void establish_demotion_targets(void) {}
#endif /* CONFIG_MIGRATION */
static inline void __init_node_memory_type(int node, struct memory_dev_type *memtype)
{
if (!node_memory_types[node].memtype)
node_memory_types[node].memtype = memtype;
/*
* for each device getting added in the same NUMA node
* with this specific memtype, bump the map count. We
* Only take memtype device reference once, so that
* changing a node memtype can be done by droping the
* only reference count taken here.
*/
if (node_memory_types[node].memtype == memtype) {
if (!node_memory_types[node].map_count++)
kref_get(&memtype->kref);
}
}
static struct memory_tier *set_node_memory_tier(int node)
{
struct memory_tier *memtier;
struct memory_dev_type *memtype;
pg_data_t *pgdat = NODE_DATA(node);
lockdep_assert_held_once(&memory_tier_lock);
if (!node_state(node, N_MEMORY))
return ERR_PTR(-EINVAL);
__init_node_memory_type(node, default_dram_type);
memtype = node_memory_types[node].memtype;
node_set(node, memtype->nodes);
memtier = find_create_memory_tier(memtype);
if (!IS_ERR(memtier))
rcu_assign_pointer(pgdat->memtier, memtier);
return memtier;
}
static void destroy_memory_tier(struct memory_tier *memtier)
{
list_del(&memtier->list);
device_unregister(&memtier->dev);
}
static bool clear_node_memory_tier(int node)
{
bool cleared = false;
pg_data_t *pgdat;
struct memory_tier *memtier;
pgdat = NODE_DATA(node);
if (!pgdat)
return false;
/*
* Make sure that anybody looking at NODE_DATA who finds
* a valid memtier finds memory_dev_types with nodes still
* linked to the memtier. We achieve this by waiting for
* rcu read section to finish using synchronize_rcu.
* This also enables us to free the destroyed memory tier
* with kfree instead of kfree_rcu
*/
memtier = __node_get_memory_tier(node);
if (memtier) {
struct memory_dev_type *memtype;
rcu_assign_pointer(pgdat->memtier, NULL);
synchronize_rcu();
memtype = node_memory_types[node].memtype;
node_clear(node, memtype->nodes);
if (nodes_empty(memtype->nodes)) {
list_del_init(&memtype->tier_sibiling);
if (list_empty(&memtier->memory_types))
destroy_memory_tier(memtier);
}
cleared = true;
}
return cleared;
}
static void release_memtype(struct kref *kref)
{
struct memory_dev_type *memtype;
memtype = container_of(kref, struct memory_dev_type, kref);
kfree(memtype);
}
struct memory_dev_type *alloc_memory_type(int adistance)
{
struct memory_dev_type *memtype;
memtype = kmalloc(sizeof(*memtype), GFP_KERNEL);
if (!memtype)
return ERR_PTR(-ENOMEM);
memtype->adistance = adistance;
INIT_LIST_HEAD(&memtype->tier_sibiling);
memtype->nodes = NODE_MASK_NONE;
kref_init(&memtype->kref);
return memtype;
}
EXPORT_SYMBOL_GPL(alloc_memory_type);
void put_memory_type(struct memory_dev_type *memtype)
{
kref_put(&memtype->kref, release_memtype);
}
EXPORT_SYMBOL_GPL(put_memory_type);
void init_node_memory_type(int node, struct memory_dev_type *memtype)
{
mutex_lock(&memory_tier_lock);
__init_node_memory_type(node, memtype);
mutex_unlock(&memory_tier_lock);
}
EXPORT_SYMBOL_GPL(init_node_memory_type);
void clear_node_memory_type(int node, struct memory_dev_type *memtype)
{
mutex_lock(&memory_tier_lock);
if (node_memory_types[node].memtype == memtype)
node_memory_types[node].map_count--;
/*
* If we umapped all the attached devices to this node,
* clear the node memory type.
*/
if (!node_memory_types[node].map_count) {
node_memory_types[node].memtype = NULL;
put_memory_type(memtype);
}
mutex_unlock(&memory_tier_lock);
}
EXPORT_SYMBOL_GPL(clear_node_memory_type);
static int __meminit memtier_hotplug_callback(struct notifier_block *self,
unsigned long action, void *_arg)
{
struct memory_tier *memtier;
struct memory_notify *arg = _arg;
/*
* Only update the node migration order when a node is
* changing status, like online->offline.
*/
if (arg->status_change_nid < 0)
return notifier_from_errno(0);
switch (action) {
case MEM_OFFLINE:
mutex_lock(&memory_tier_lock);
if (clear_node_memory_tier(arg->status_change_nid))
establish_demotion_targets();
mutex_unlock(&memory_tier_lock);
break;
case MEM_ONLINE:
mutex_lock(&memory_tier_lock);
memtier = set_node_memory_tier(arg->status_change_nid);
if (!IS_ERR(memtier))
establish_demotion_targets();
mutex_unlock(&memory_tier_lock);
break;
}
return notifier_from_errno(0);
}
static int __init memory_tier_init(void)
{
int ret, node;
struct memory_tier *memtier;
ret = subsys_virtual_register(&memory_tier_subsys, NULL);
if (ret)
panic("%s() failed to register memory tier subsystem\n", __func__);
#ifdef CONFIG_MIGRATION
node_demotion = kcalloc(nr_node_ids, sizeof(struct demotion_nodes),
GFP_KERNEL);
WARN_ON(!node_demotion);
#endif
mutex_lock(&memory_tier_lock);
/*
* For now we can have 4 faster memory tiers with smaller adistance
* than default DRAM tier.
*/
default_dram_type = alloc_memory_type(MEMTIER_ADISTANCE_DRAM);
if (IS_ERR(default_dram_type))
panic("%s() failed to allocate default DRAM tier\n", __func__);
/*
* Look at all the existing N_MEMORY nodes and add them to
* default memory tier or to a tier if we already have memory
* types assigned.
*/
for_each_node_state(node, N_MEMORY) {
memtier = set_node_memory_tier(node);
if (IS_ERR(memtier))
/*
* Continue with memtiers we are able to setup
*/
break;
}
establish_demotion_targets();
mutex_unlock(&memory_tier_lock);
hotplug_memory_notifier(memtier_hotplug_callback, MEMTIER_HOTPLUG_PRI);
return 0;
}
subsys_initcall(memory_tier_init);
bool numa_demotion_enabled = false;
#ifdef CONFIG_MIGRATION
#ifdef CONFIG_SYSFS
static ssize_t demotion_enabled_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
return sysfs_emit(buf, "%s\n",
numa_demotion_enabled ? "true" : "false");
}
static ssize_t demotion_enabled_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
{
ssize_t ret;
ret = kstrtobool(buf, &numa_demotion_enabled);
if (ret)
return ret;
return count;
}
static struct kobj_attribute numa_demotion_enabled_attr =
__ATTR_RW(demotion_enabled);
static struct attribute *numa_attrs[] = {
&numa_demotion_enabled_attr.attr,
NULL,
};
static const struct attribute_group numa_attr_group = {
.attrs = numa_attrs,
};
static int __init numa_init_sysfs(void)
{
int err;
struct kobject *numa_kobj;
numa_kobj = kobject_create_and_add("numa", mm_kobj);
if (!numa_kobj) {
pr_err("failed to create numa kobject\n");
return -ENOMEM;
}
err = sysfs_create_group(numa_kobj, &numa_attr_group);
if (err) {
pr_err("failed to register numa group\n");
goto delete_obj;
}
return 0;
delete_obj:
kobject_put(numa_kobj);
return err;
}
subsys_initcall(numa_init_sysfs);
#endif /* CONFIG_SYSFS */
#endif
| linux-master | mm/memory-tiers.c |
// SPDX-License-Identifier: GPL-2.0
#define CREATE_TRACE_POINTS
#include <trace/events/mmap_lock.h>
#include <linux/mm.h>
#include <linux/cgroup.h>
#include <linux/memcontrol.h>
#include <linux/mmap_lock.h>
#include <linux/mutex.h>
#include <linux/percpu.h>
#include <linux/rcupdate.h>
#include <linux/smp.h>
#include <linux/trace_events.h>
#include <linux/local_lock.h>
EXPORT_TRACEPOINT_SYMBOL(mmap_lock_start_locking);
EXPORT_TRACEPOINT_SYMBOL(mmap_lock_acquire_returned);
EXPORT_TRACEPOINT_SYMBOL(mmap_lock_released);
#ifdef CONFIG_MEMCG
/*
* Our various events all share the same buffer (because we don't want or need
* to allocate a set of buffers *per event type*), so we need to protect against
* concurrent _reg() and _unreg() calls, and count how many _reg() calls have
* been made.
*/
static DEFINE_MUTEX(reg_lock);
static int reg_refcount; /* Protected by reg_lock. */
/*
* Size of the buffer for memcg path names. Ignoring stack trace support,
* trace_events_hist.c uses MAX_FILTER_STR_VAL for this, so we also use it.
*/
#define MEMCG_PATH_BUF_SIZE MAX_FILTER_STR_VAL
/*
* How many contexts our trace events might be called in: normal, softirq, irq,
* and NMI.
*/
#define CONTEXT_COUNT 4
struct memcg_path {
local_lock_t lock;
char __rcu *buf;
local_t buf_idx;
};
static DEFINE_PER_CPU(struct memcg_path, memcg_paths) = {
.lock = INIT_LOCAL_LOCK(lock),
.buf_idx = LOCAL_INIT(0),
};
static char **tmp_bufs;
/* Called with reg_lock held. */
static void free_memcg_path_bufs(void)
{
struct memcg_path *memcg_path;
int cpu;
char **old = tmp_bufs;
for_each_possible_cpu(cpu) {
memcg_path = per_cpu_ptr(&memcg_paths, cpu);
*(old++) = rcu_dereference_protected(memcg_path->buf,
lockdep_is_held(®_lock));
rcu_assign_pointer(memcg_path->buf, NULL);
}
/* Wait for inflight memcg_path_buf users to finish. */
synchronize_rcu();
old = tmp_bufs;
for_each_possible_cpu(cpu) {
kfree(*(old++));
}
kfree(tmp_bufs);
tmp_bufs = NULL;
}
int trace_mmap_lock_reg(void)
{
int cpu;
char *new;
mutex_lock(®_lock);
/* If the refcount is going 0->1, proceed with allocating buffers. */
if (reg_refcount++)
goto out;
tmp_bufs = kmalloc_array(num_possible_cpus(), sizeof(*tmp_bufs),
GFP_KERNEL);
if (tmp_bufs == NULL)
goto out_fail;
for_each_possible_cpu(cpu) {
new = kmalloc(MEMCG_PATH_BUF_SIZE * CONTEXT_COUNT, GFP_KERNEL);
if (new == NULL)
goto out_fail_free;
rcu_assign_pointer(per_cpu_ptr(&memcg_paths, cpu)->buf, new);
/* Don't need to wait for inflights, they'd have gotten NULL. */
}
out:
mutex_unlock(®_lock);
return 0;
out_fail_free:
free_memcg_path_bufs();
out_fail:
/* Since we failed, undo the earlier ref increment. */
--reg_refcount;
mutex_unlock(®_lock);
return -ENOMEM;
}
void trace_mmap_lock_unreg(void)
{
mutex_lock(®_lock);
/* If the refcount is going 1->0, proceed with freeing buffers. */
if (--reg_refcount)
goto out;
free_memcg_path_bufs();
out:
mutex_unlock(®_lock);
}
static inline char *get_memcg_path_buf(void)
{
struct memcg_path *memcg_path = this_cpu_ptr(&memcg_paths);
char *buf;
int idx;
rcu_read_lock();
buf = rcu_dereference(memcg_path->buf);
if (buf == NULL) {
rcu_read_unlock();
return NULL;
}
idx = local_add_return(MEMCG_PATH_BUF_SIZE, &memcg_path->buf_idx) -
MEMCG_PATH_BUF_SIZE;
return &buf[idx];
}
static inline void put_memcg_path_buf(void)
{
local_sub(MEMCG_PATH_BUF_SIZE, &this_cpu_ptr(&memcg_paths)->buf_idx);
rcu_read_unlock();
}
#define TRACE_MMAP_LOCK_EVENT(type, mm, ...) \
do { \
const char *memcg_path; \
local_lock(&memcg_paths.lock); \
memcg_path = get_mm_memcg_path(mm); \
trace_mmap_lock_##type(mm, \
memcg_path != NULL ? memcg_path : "", \
##__VA_ARGS__); \
if (likely(memcg_path != NULL)) \
put_memcg_path_buf(); \
local_unlock(&memcg_paths.lock); \
} while (0)
#else /* !CONFIG_MEMCG */
int trace_mmap_lock_reg(void)
{
return 0;
}
void trace_mmap_lock_unreg(void)
{
}
#define TRACE_MMAP_LOCK_EVENT(type, mm, ...) \
trace_mmap_lock_##type(mm, "", ##__VA_ARGS__)
#endif /* CONFIG_MEMCG */
#ifdef CONFIG_TRACING
#ifdef CONFIG_MEMCG
/*
* Write the given mm_struct's memcg path to a percpu buffer, and return a
* pointer to it. If the path cannot be determined, or no buffer was available
* (because the trace event is being unregistered), NULL is returned.
*
* Note: buffers are allocated per-cpu to avoid locking, so preemption must be
* disabled by the caller before calling us, and re-enabled only after the
* caller is done with the pointer.
*
* The caller must call put_memcg_path_buf() once the buffer is no longer
* needed. This must be done while preemption is still disabled.
*/
static const char *get_mm_memcg_path(struct mm_struct *mm)
{
char *buf = NULL;
struct mem_cgroup *memcg = get_mem_cgroup_from_mm(mm);
if (memcg == NULL)
goto out;
if (unlikely(memcg->css.cgroup == NULL))
goto out_put;
buf = get_memcg_path_buf();
if (buf == NULL)
goto out_put;
cgroup_path(memcg->css.cgroup, buf, MEMCG_PATH_BUF_SIZE);
out_put:
css_put(&memcg->css);
out:
return buf;
}
#endif /* CONFIG_MEMCG */
/*
* Trace calls must be in a separate file, as otherwise there's a circular
* dependency between linux/mmap_lock.h and trace/events/mmap_lock.h.
*/
void __mmap_lock_do_trace_start_locking(struct mm_struct *mm, bool write)
{
TRACE_MMAP_LOCK_EVENT(start_locking, mm, write);
}
EXPORT_SYMBOL(__mmap_lock_do_trace_start_locking);
void __mmap_lock_do_trace_acquire_returned(struct mm_struct *mm, bool write,
bool success)
{
TRACE_MMAP_LOCK_EVENT(acquire_returned, mm, write, success);
}
EXPORT_SYMBOL(__mmap_lock_do_trace_acquire_returned);
void __mmap_lock_do_trace_released(struct mm_struct *mm, bool write)
{
TRACE_MMAP_LOCK_EVENT(released, mm, write);
}
EXPORT_SYMBOL(__mmap_lock_do_trace_released);
#endif /* CONFIG_TRACING */
| linux-master | mm/mmap_lock.c |
/*
* zsmalloc memory allocator
*
* Copyright (C) 2011 Nitin Gupta
* Copyright (C) 2012, 2013 Minchan Kim
*
* This code is released using a dual license strategy: BSD/GPL
* You can choose the license that better fits your requirements.
*
* Released under the terms of 3-clause BSD License
* Released under the terms of GNU General Public License Version 2.0
*/
/*
* Following is how we use various fields and flags of underlying
* struct page(s) to form a zspage.
*
* Usage of struct page fields:
* page->private: points to zspage
* page->index: links together all component pages of a zspage
* For the huge page, this is always 0, so we use this field
* to store handle.
* page->page_type: first object offset in a subpage of zspage
*
* Usage of struct page flags:
* PG_private: identifies the first component page
* PG_owner_priv_1: identifies the huge component page
*
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
/*
* lock ordering:
* page_lock
* pool->lock
* zspage->lock
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/bitops.h>
#include <linux/errno.h>
#include <linux/highmem.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/pgtable.h>
#include <asm/tlbflush.h>
#include <linux/cpumask.h>
#include <linux/cpu.h>
#include <linux/vmalloc.h>
#include <linux/preempt.h>
#include <linux/spinlock.h>
#include <linux/shrinker.h>
#include <linux/types.h>
#include <linux/debugfs.h>
#include <linux/zsmalloc.h>
#include <linux/zpool.h>
#include <linux/migrate.h>
#include <linux/wait.h>
#include <linux/pagemap.h>
#include <linux/fs.h>
#include <linux/local_lock.h>
#define ZSPAGE_MAGIC 0x58
/*
* This must be power of 2 and greater than or equal to sizeof(link_free).
* These two conditions ensure that any 'struct link_free' itself doesn't
* span more than 1 page which avoids complex case of mapping 2 pages simply
* to restore link_free pointer values.
*/
#define ZS_ALIGN 8
#define ZS_HANDLE_SIZE (sizeof(unsigned long))
/*
* Object location (<PFN>, <obj_idx>) is encoded as
* a single (unsigned long) handle value.
*
* Note that object index <obj_idx> starts from 0.
*
* This is made more complicated by various memory models and PAE.
*/
#ifndef MAX_POSSIBLE_PHYSMEM_BITS
#ifdef MAX_PHYSMEM_BITS
#define MAX_POSSIBLE_PHYSMEM_BITS MAX_PHYSMEM_BITS
#else
/*
* If this definition of MAX_PHYSMEM_BITS is used, OBJ_INDEX_BITS will just
* be PAGE_SHIFT
*/
#define MAX_POSSIBLE_PHYSMEM_BITS BITS_PER_LONG
#endif
#endif
#define _PFN_BITS (MAX_POSSIBLE_PHYSMEM_BITS - PAGE_SHIFT)
/*
* Head in allocated object should have OBJ_ALLOCATED_TAG
* to identify the object was allocated or not.
* It's okay to add the status bit in the least bit because
* header keeps handle which is 4byte-aligned address so we
* have room for two bit at least.
*/
#define OBJ_ALLOCATED_TAG 1
#define OBJ_TAG_BITS 1
#define OBJ_TAG_MASK OBJ_ALLOCATED_TAG
#define OBJ_INDEX_BITS (BITS_PER_LONG - _PFN_BITS - OBJ_TAG_BITS)
#define OBJ_INDEX_MASK ((_AC(1, UL) << OBJ_INDEX_BITS) - 1)
#define HUGE_BITS 1
#define FULLNESS_BITS 4
#define CLASS_BITS 8
#define ISOLATED_BITS 5
#define MAGIC_VAL_BITS 8
#define MAX(a, b) ((a) >= (b) ? (a) : (b))
#define ZS_MAX_PAGES_PER_ZSPAGE (_AC(CONFIG_ZSMALLOC_CHAIN_SIZE, UL))
/* ZS_MIN_ALLOC_SIZE must be multiple of ZS_ALIGN */
#define ZS_MIN_ALLOC_SIZE \
MAX(32, (ZS_MAX_PAGES_PER_ZSPAGE << PAGE_SHIFT >> OBJ_INDEX_BITS))
/* each chunk includes extra space to keep handle */
#define ZS_MAX_ALLOC_SIZE PAGE_SIZE
/*
* On systems with 4K page size, this gives 255 size classes! There is a
* trader-off here:
* - Large number of size classes is potentially wasteful as free page are
* spread across these classes
* - Small number of size classes causes large internal fragmentation
* - Probably its better to use specific size classes (empirically
* determined). NOTE: all those class sizes must be set as multiple of
* ZS_ALIGN to make sure link_free itself never has to span 2 pages.
*
* ZS_MIN_ALLOC_SIZE and ZS_SIZE_CLASS_DELTA must be multiple of ZS_ALIGN
* (reason above)
*/
#define ZS_SIZE_CLASS_DELTA (PAGE_SIZE >> CLASS_BITS)
#define ZS_SIZE_CLASSES (DIV_ROUND_UP(ZS_MAX_ALLOC_SIZE - ZS_MIN_ALLOC_SIZE, \
ZS_SIZE_CLASS_DELTA) + 1)
/*
* Pages are distinguished by the ratio of used memory (that is the ratio
* of ->inuse objects to all objects that page can store). For example,
* INUSE_RATIO_10 means that the ratio of used objects is > 0% and <= 10%.
*
* The number of fullness groups is not random. It allows us to keep
* difference between the least busy page in the group (minimum permitted
* number of ->inuse objects) and the most busy page (maximum permitted
* number of ->inuse objects) at a reasonable value.
*/
enum fullness_group {
ZS_INUSE_RATIO_0,
ZS_INUSE_RATIO_10,
/* NOTE: 8 more fullness groups here */
ZS_INUSE_RATIO_99 = 10,
ZS_INUSE_RATIO_100,
NR_FULLNESS_GROUPS,
};
enum class_stat_type {
/* NOTE: stats for 12 fullness groups here: from inuse 0 to 100 */
ZS_OBJS_ALLOCATED = NR_FULLNESS_GROUPS,
ZS_OBJS_INUSE,
NR_CLASS_STAT_TYPES,
};
struct zs_size_stat {
unsigned long objs[NR_CLASS_STAT_TYPES];
};
#ifdef CONFIG_ZSMALLOC_STAT
static struct dentry *zs_stat_root;
#endif
static size_t huge_class_size;
struct size_class {
struct list_head fullness_list[NR_FULLNESS_GROUPS];
/*
* Size of objects stored in this class. Must be multiple
* of ZS_ALIGN.
*/
int size;
int objs_per_zspage;
/* Number of PAGE_SIZE sized pages to combine to form a 'zspage' */
int pages_per_zspage;
unsigned int index;
struct zs_size_stat stats;
};
/*
* Placed within free objects to form a singly linked list.
* For every zspage, zspage->freeobj gives head of this list.
*
* This must be power of 2 and less than or equal to ZS_ALIGN
*/
struct link_free {
union {
/*
* Free object index;
* It's valid for non-allocated object
*/
unsigned long next;
/*
* Handle of allocated object.
*/
unsigned long handle;
};
};
struct zs_pool {
const char *name;
struct size_class *size_class[ZS_SIZE_CLASSES];
struct kmem_cache *handle_cachep;
struct kmem_cache *zspage_cachep;
atomic_long_t pages_allocated;
struct zs_pool_stats stats;
/* Compact classes */
struct shrinker shrinker;
#ifdef CONFIG_ZSMALLOC_STAT
struct dentry *stat_dentry;
#endif
#ifdef CONFIG_COMPACTION
struct work_struct free_work;
#endif
spinlock_t lock;
atomic_t compaction_in_progress;
};
struct zspage {
struct {
unsigned int huge:HUGE_BITS;
unsigned int fullness:FULLNESS_BITS;
unsigned int class:CLASS_BITS + 1;
unsigned int isolated:ISOLATED_BITS;
unsigned int magic:MAGIC_VAL_BITS;
};
unsigned int inuse;
unsigned int freeobj;
struct page *first_page;
struct list_head list; /* fullness list */
struct zs_pool *pool;
rwlock_t lock;
};
struct mapping_area {
local_lock_t lock;
char *vm_buf; /* copy buffer for objects that span pages */
char *vm_addr; /* address of kmap_atomic()'ed pages */
enum zs_mapmode vm_mm; /* mapping mode */
};
/* huge object: pages_per_zspage == 1 && maxobj_per_zspage == 1 */
static void SetZsHugePage(struct zspage *zspage)
{
zspage->huge = 1;
}
static bool ZsHugePage(struct zspage *zspage)
{
return zspage->huge;
}
static void migrate_lock_init(struct zspage *zspage);
static void migrate_read_lock(struct zspage *zspage);
static void migrate_read_unlock(struct zspage *zspage);
#ifdef CONFIG_COMPACTION
static void migrate_write_lock(struct zspage *zspage);
static void migrate_write_lock_nested(struct zspage *zspage);
static void migrate_write_unlock(struct zspage *zspage);
static void kick_deferred_free(struct zs_pool *pool);
static void init_deferred_free(struct zs_pool *pool);
static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage);
#else
static void migrate_write_lock(struct zspage *zspage) {}
static void migrate_write_lock_nested(struct zspage *zspage) {}
static void migrate_write_unlock(struct zspage *zspage) {}
static void kick_deferred_free(struct zs_pool *pool) {}
static void init_deferred_free(struct zs_pool *pool) {}
static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage) {}
#endif
static int create_cache(struct zs_pool *pool)
{
pool->handle_cachep = kmem_cache_create("zs_handle", ZS_HANDLE_SIZE,
0, 0, NULL);
if (!pool->handle_cachep)
return 1;
pool->zspage_cachep = kmem_cache_create("zspage", sizeof(struct zspage),
0, 0, NULL);
if (!pool->zspage_cachep) {
kmem_cache_destroy(pool->handle_cachep);
pool->handle_cachep = NULL;
return 1;
}
return 0;
}
static void destroy_cache(struct zs_pool *pool)
{
kmem_cache_destroy(pool->handle_cachep);
kmem_cache_destroy(pool->zspage_cachep);
}
static unsigned long cache_alloc_handle(struct zs_pool *pool, gfp_t gfp)
{
return (unsigned long)kmem_cache_alloc(pool->handle_cachep,
gfp & ~(__GFP_HIGHMEM|__GFP_MOVABLE));
}
static void cache_free_handle(struct zs_pool *pool, unsigned long handle)
{
kmem_cache_free(pool->handle_cachep, (void *)handle);
}
static struct zspage *cache_alloc_zspage(struct zs_pool *pool, gfp_t flags)
{
return kmem_cache_zalloc(pool->zspage_cachep,
flags & ~(__GFP_HIGHMEM|__GFP_MOVABLE));
}
static void cache_free_zspage(struct zs_pool *pool, struct zspage *zspage)
{
kmem_cache_free(pool->zspage_cachep, zspage);
}
/* pool->lock(which owns the handle) synchronizes races */
static void record_obj(unsigned long handle, unsigned long obj)
{
*(unsigned long *)handle = obj;
}
/* zpool driver */
#ifdef CONFIG_ZPOOL
static void *zs_zpool_create(const char *name, gfp_t gfp)
{
/*
* Ignore global gfp flags: zs_malloc() may be invoked from
* different contexts and its caller must provide a valid
* gfp mask.
*/
return zs_create_pool(name);
}
static void zs_zpool_destroy(void *pool)
{
zs_destroy_pool(pool);
}
static int zs_zpool_malloc(void *pool, size_t size, gfp_t gfp,
unsigned long *handle)
{
*handle = zs_malloc(pool, size, gfp);
if (IS_ERR_VALUE(*handle))
return PTR_ERR((void *)*handle);
return 0;
}
static void zs_zpool_free(void *pool, unsigned long handle)
{
zs_free(pool, handle);
}
static void *zs_zpool_map(void *pool, unsigned long handle,
enum zpool_mapmode mm)
{
enum zs_mapmode zs_mm;
switch (mm) {
case ZPOOL_MM_RO:
zs_mm = ZS_MM_RO;
break;
case ZPOOL_MM_WO:
zs_mm = ZS_MM_WO;
break;
case ZPOOL_MM_RW:
default:
zs_mm = ZS_MM_RW;
break;
}
return zs_map_object(pool, handle, zs_mm);
}
static void zs_zpool_unmap(void *pool, unsigned long handle)
{
zs_unmap_object(pool, handle);
}
static u64 zs_zpool_total_size(void *pool)
{
return zs_get_total_pages(pool) << PAGE_SHIFT;
}
static struct zpool_driver zs_zpool_driver = {
.type = "zsmalloc",
.owner = THIS_MODULE,
.create = zs_zpool_create,
.destroy = zs_zpool_destroy,
.malloc_support_movable = true,
.malloc = zs_zpool_malloc,
.free = zs_zpool_free,
.map = zs_zpool_map,
.unmap = zs_zpool_unmap,
.total_size = zs_zpool_total_size,
};
MODULE_ALIAS("zpool-zsmalloc");
#endif /* CONFIG_ZPOOL */
/* per-cpu VM mapping areas for zspage accesses that cross page boundaries */
static DEFINE_PER_CPU(struct mapping_area, zs_map_area) = {
.lock = INIT_LOCAL_LOCK(lock),
};
static __maybe_unused int is_first_page(struct page *page)
{
return PagePrivate(page);
}
/* Protected by pool->lock */
static inline int get_zspage_inuse(struct zspage *zspage)
{
return zspage->inuse;
}
static inline void mod_zspage_inuse(struct zspage *zspage, int val)
{
zspage->inuse += val;
}
static inline struct page *get_first_page(struct zspage *zspage)
{
struct page *first_page = zspage->first_page;
VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
return first_page;
}
static inline unsigned int get_first_obj_offset(struct page *page)
{
return page->page_type;
}
static inline void set_first_obj_offset(struct page *page, unsigned int offset)
{
page->page_type = offset;
}
static inline unsigned int get_freeobj(struct zspage *zspage)
{
return zspage->freeobj;
}
static inline void set_freeobj(struct zspage *zspage, unsigned int obj)
{
zspage->freeobj = obj;
}
static void get_zspage_mapping(struct zspage *zspage,
unsigned int *class_idx,
int *fullness)
{
BUG_ON(zspage->magic != ZSPAGE_MAGIC);
*fullness = zspage->fullness;
*class_idx = zspage->class;
}
static struct size_class *zspage_class(struct zs_pool *pool,
struct zspage *zspage)
{
return pool->size_class[zspage->class];
}
static void set_zspage_mapping(struct zspage *zspage,
unsigned int class_idx,
int fullness)
{
zspage->class = class_idx;
zspage->fullness = fullness;
}
/*
* zsmalloc divides the pool into various size classes where each
* class maintains a list of zspages where each zspage is divided
* into equal sized chunks. Each allocation falls into one of these
* classes depending on its size. This function returns index of the
* size class which has chunk size big enough to hold the given size.
*/
static int get_size_class_index(int size)
{
int idx = 0;
if (likely(size > ZS_MIN_ALLOC_SIZE))
idx = DIV_ROUND_UP(size - ZS_MIN_ALLOC_SIZE,
ZS_SIZE_CLASS_DELTA);
return min_t(int, ZS_SIZE_CLASSES - 1, idx);
}
static inline void class_stat_inc(struct size_class *class,
int type, unsigned long cnt)
{
class->stats.objs[type] += cnt;
}
static inline void class_stat_dec(struct size_class *class,
int type, unsigned long cnt)
{
class->stats.objs[type] -= cnt;
}
static inline unsigned long zs_stat_get(struct size_class *class, int type)
{
return class->stats.objs[type];
}
#ifdef CONFIG_ZSMALLOC_STAT
static void __init zs_stat_init(void)
{
if (!debugfs_initialized()) {
pr_warn("debugfs not available, stat dir not created\n");
return;
}
zs_stat_root = debugfs_create_dir("zsmalloc", NULL);
}
static void __exit zs_stat_exit(void)
{
debugfs_remove_recursive(zs_stat_root);
}
static unsigned long zs_can_compact(struct size_class *class);
static int zs_stats_size_show(struct seq_file *s, void *v)
{
int i, fg;
struct zs_pool *pool = s->private;
struct size_class *class;
int objs_per_zspage;
unsigned long obj_allocated, obj_used, pages_used, freeable;
unsigned long total_objs = 0, total_used_objs = 0, total_pages = 0;
unsigned long total_freeable = 0;
unsigned long inuse_totals[NR_FULLNESS_GROUPS] = {0, };
seq_printf(s, " %5s %5s %9s %9s %9s %9s %9s %9s %9s %9s %9s %9s %9s %13s %10s %10s %16s %8s\n",
"class", "size", "10%", "20%", "30%", "40%",
"50%", "60%", "70%", "80%", "90%", "99%", "100%",
"obj_allocated", "obj_used", "pages_used",
"pages_per_zspage", "freeable");
for (i = 0; i < ZS_SIZE_CLASSES; i++) {
class = pool->size_class[i];
if (class->index != i)
continue;
spin_lock(&pool->lock);
seq_printf(s, " %5u %5u ", i, class->size);
for (fg = ZS_INUSE_RATIO_10; fg < NR_FULLNESS_GROUPS; fg++) {
inuse_totals[fg] += zs_stat_get(class, fg);
seq_printf(s, "%9lu ", zs_stat_get(class, fg));
}
obj_allocated = zs_stat_get(class, ZS_OBJS_ALLOCATED);
obj_used = zs_stat_get(class, ZS_OBJS_INUSE);
freeable = zs_can_compact(class);
spin_unlock(&pool->lock);
objs_per_zspage = class->objs_per_zspage;
pages_used = obj_allocated / objs_per_zspage *
class->pages_per_zspage;
seq_printf(s, "%13lu %10lu %10lu %16d %8lu\n",
obj_allocated, obj_used, pages_used,
class->pages_per_zspage, freeable);
total_objs += obj_allocated;
total_used_objs += obj_used;
total_pages += pages_used;
total_freeable += freeable;
}
seq_puts(s, "\n");
seq_printf(s, " %5s %5s ", "Total", "");
for (fg = ZS_INUSE_RATIO_10; fg < NR_FULLNESS_GROUPS; fg++)
seq_printf(s, "%9lu ", inuse_totals[fg]);
seq_printf(s, "%13lu %10lu %10lu %16s %8lu\n",
total_objs, total_used_objs, total_pages, "",
total_freeable);
return 0;
}
DEFINE_SHOW_ATTRIBUTE(zs_stats_size);
static void zs_pool_stat_create(struct zs_pool *pool, const char *name)
{
if (!zs_stat_root) {
pr_warn("no root stat dir, not creating <%s> stat dir\n", name);
return;
}
pool->stat_dentry = debugfs_create_dir(name, zs_stat_root);
debugfs_create_file("classes", S_IFREG | 0444, pool->stat_dentry, pool,
&zs_stats_size_fops);
}
static void zs_pool_stat_destroy(struct zs_pool *pool)
{
debugfs_remove_recursive(pool->stat_dentry);
}
#else /* CONFIG_ZSMALLOC_STAT */
static void __init zs_stat_init(void)
{
}
static void __exit zs_stat_exit(void)
{
}
static inline void zs_pool_stat_create(struct zs_pool *pool, const char *name)
{
}
static inline void zs_pool_stat_destroy(struct zs_pool *pool)
{
}
#endif
/*
* For each size class, zspages are divided into different groups
* depending on their usage ratio. This function returns fullness
* status of the given page.
*/
static int get_fullness_group(struct size_class *class, struct zspage *zspage)
{
int inuse, objs_per_zspage, ratio;
inuse = get_zspage_inuse(zspage);
objs_per_zspage = class->objs_per_zspage;
if (inuse == 0)
return ZS_INUSE_RATIO_0;
if (inuse == objs_per_zspage)
return ZS_INUSE_RATIO_100;
ratio = 100 * inuse / objs_per_zspage;
/*
* Take integer division into consideration: a page with one inuse
* object out of 127 possible, will end up having 0 usage ratio,
* which is wrong as it belongs in ZS_INUSE_RATIO_10 fullness group.
*/
return ratio / 10 + 1;
}
/*
* Each size class maintains various freelists and zspages are assigned
* to one of these freelists based on the number of live objects they
* have. This functions inserts the given zspage into the freelist
* identified by <class, fullness_group>.
*/
static void insert_zspage(struct size_class *class,
struct zspage *zspage,
int fullness)
{
class_stat_inc(class, fullness, 1);
list_add(&zspage->list, &class->fullness_list[fullness]);
}
/*
* This function removes the given zspage from the freelist identified
* by <class, fullness_group>.
*/
static void remove_zspage(struct size_class *class,
struct zspage *zspage,
int fullness)
{
VM_BUG_ON(list_empty(&class->fullness_list[fullness]));
list_del_init(&zspage->list);
class_stat_dec(class, fullness, 1);
}
/*
* Each size class maintains zspages in different fullness groups depending
* on the number of live objects they contain. When allocating or freeing
* objects, the fullness status of the page can change, for instance, from
* INUSE_RATIO_80 to INUSE_RATIO_70 when freeing an object. This function
* checks if such a status change has occurred for the given page and
* accordingly moves the page from the list of the old fullness group to that
* of the new fullness group.
*/
static int fix_fullness_group(struct size_class *class, struct zspage *zspage)
{
int class_idx;
int currfg, newfg;
get_zspage_mapping(zspage, &class_idx, &currfg);
newfg = get_fullness_group(class, zspage);
if (newfg == currfg)
goto out;
remove_zspage(class, zspage, currfg);
insert_zspage(class, zspage, newfg);
set_zspage_mapping(zspage, class_idx, newfg);
out:
return newfg;
}
static struct zspage *get_zspage(struct page *page)
{
struct zspage *zspage = (struct zspage *)page_private(page);
BUG_ON(zspage->magic != ZSPAGE_MAGIC);
return zspage;
}
static struct page *get_next_page(struct page *page)
{
struct zspage *zspage = get_zspage(page);
if (unlikely(ZsHugePage(zspage)))
return NULL;
return (struct page *)page->index;
}
/**
* obj_to_location - get (<page>, <obj_idx>) from encoded object value
* @obj: the encoded object value
* @page: page object resides in zspage
* @obj_idx: object index
*/
static void obj_to_location(unsigned long obj, struct page **page,
unsigned int *obj_idx)
{
obj >>= OBJ_TAG_BITS;
*page = pfn_to_page(obj >> OBJ_INDEX_BITS);
*obj_idx = (obj & OBJ_INDEX_MASK);
}
static void obj_to_page(unsigned long obj, struct page **page)
{
obj >>= OBJ_TAG_BITS;
*page = pfn_to_page(obj >> OBJ_INDEX_BITS);
}
/**
* location_to_obj - get obj value encoded from (<page>, <obj_idx>)
* @page: page object resides in zspage
* @obj_idx: object index
*/
static unsigned long location_to_obj(struct page *page, unsigned int obj_idx)
{
unsigned long obj;
obj = page_to_pfn(page) << OBJ_INDEX_BITS;
obj |= obj_idx & OBJ_INDEX_MASK;
obj <<= OBJ_TAG_BITS;
return obj;
}
static unsigned long handle_to_obj(unsigned long handle)
{
return *(unsigned long *)handle;
}
static inline bool obj_allocated(struct page *page, void *obj,
unsigned long *phandle)
{
unsigned long handle;
struct zspage *zspage = get_zspage(page);
if (unlikely(ZsHugePage(zspage))) {
VM_BUG_ON_PAGE(!is_first_page(page), page);
handle = page->index;
} else
handle = *(unsigned long *)obj;
if (!(handle & OBJ_ALLOCATED_TAG))
return false;
/* Clear all tags before returning the handle */
*phandle = handle & ~OBJ_TAG_MASK;
return true;
}
static void reset_page(struct page *page)
{
__ClearPageMovable(page);
ClearPagePrivate(page);
set_page_private(page, 0);
page_mapcount_reset(page);
page->index = 0;
}
static int trylock_zspage(struct zspage *zspage)
{
struct page *cursor, *fail;
for (cursor = get_first_page(zspage); cursor != NULL; cursor =
get_next_page(cursor)) {
if (!trylock_page(cursor)) {
fail = cursor;
goto unlock;
}
}
return 1;
unlock:
for (cursor = get_first_page(zspage); cursor != fail; cursor =
get_next_page(cursor))
unlock_page(cursor);
return 0;
}
static void __free_zspage(struct zs_pool *pool, struct size_class *class,
struct zspage *zspage)
{
struct page *page, *next;
int fg;
unsigned int class_idx;
get_zspage_mapping(zspage, &class_idx, &fg);
assert_spin_locked(&pool->lock);
VM_BUG_ON(get_zspage_inuse(zspage));
VM_BUG_ON(fg != ZS_INUSE_RATIO_0);
next = page = get_first_page(zspage);
do {
VM_BUG_ON_PAGE(!PageLocked(page), page);
next = get_next_page(page);
reset_page(page);
unlock_page(page);
dec_zone_page_state(page, NR_ZSPAGES);
put_page(page);
page = next;
} while (page != NULL);
cache_free_zspage(pool, zspage);
class_stat_dec(class, ZS_OBJS_ALLOCATED, class->objs_per_zspage);
atomic_long_sub(class->pages_per_zspage, &pool->pages_allocated);
}
static void free_zspage(struct zs_pool *pool, struct size_class *class,
struct zspage *zspage)
{
VM_BUG_ON(get_zspage_inuse(zspage));
VM_BUG_ON(list_empty(&zspage->list));
/*
* Since zs_free couldn't be sleepable, this function cannot call
* lock_page. The page locks trylock_zspage got will be released
* by __free_zspage.
*/
if (!trylock_zspage(zspage)) {
kick_deferred_free(pool);
return;
}
remove_zspage(class, zspage, ZS_INUSE_RATIO_0);
__free_zspage(pool, class, zspage);
}
/* Initialize a newly allocated zspage */
static void init_zspage(struct size_class *class, struct zspage *zspage)
{
unsigned int freeobj = 1;
unsigned long off = 0;
struct page *page = get_first_page(zspage);
while (page) {
struct page *next_page;
struct link_free *link;
void *vaddr;
set_first_obj_offset(page, off);
vaddr = kmap_atomic(page);
link = (struct link_free *)vaddr + off / sizeof(*link);
while ((off += class->size) < PAGE_SIZE) {
link->next = freeobj++ << OBJ_TAG_BITS;
link += class->size / sizeof(*link);
}
/*
* We now come to the last (full or partial) object on this
* page, which must point to the first object on the next
* page (if present)
*/
next_page = get_next_page(page);
if (next_page) {
link->next = freeobj++ << OBJ_TAG_BITS;
} else {
/*
* Reset OBJ_TAG_BITS bit to last link to tell
* whether it's allocated object or not.
*/
link->next = -1UL << OBJ_TAG_BITS;
}
kunmap_atomic(vaddr);
page = next_page;
off %= PAGE_SIZE;
}
set_freeobj(zspage, 0);
}
static void create_page_chain(struct size_class *class, struct zspage *zspage,
struct page *pages[])
{
int i;
struct page *page;
struct page *prev_page = NULL;
int nr_pages = class->pages_per_zspage;
/*
* Allocate individual pages and link them together as:
* 1. all pages are linked together using page->index
* 2. each sub-page point to zspage using page->private
*
* we set PG_private to identify the first page (i.e. no other sub-page
* has this flag set).
*/
for (i = 0; i < nr_pages; i++) {
page = pages[i];
set_page_private(page, (unsigned long)zspage);
page->index = 0;
if (i == 0) {
zspage->first_page = page;
SetPagePrivate(page);
if (unlikely(class->objs_per_zspage == 1 &&
class->pages_per_zspage == 1))
SetZsHugePage(zspage);
} else {
prev_page->index = (unsigned long)page;
}
prev_page = page;
}
}
/*
* Allocate a zspage for the given size class
*/
static struct zspage *alloc_zspage(struct zs_pool *pool,
struct size_class *class,
gfp_t gfp)
{
int i;
struct page *pages[ZS_MAX_PAGES_PER_ZSPAGE];
struct zspage *zspage = cache_alloc_zspage(pool, gfp);
if (!zspage)
return NULL;
zspage->magic = ZSPAGE_MAGIC;
migrate_lock_init(zspage);
for (i = 0; i < class->pages_per_zspage; i++) {
struct page *page;
page = alloc_page(gfp);
if (!page) {
while (--i >= 0) {
dec_zone_page_state(pages[i], NR_ZSPAGES);
__free_page(pages[i]);
}
cache_free_zspage(pool, zspage);
return NULL;
}
inc_zone_page_state(page, NR_ZSPAGES);
pages[i] = page;
}
create_page_chain(class, zspage, pages);
init_zspage(class, zspage);
zspage->pool = pool;
return zspage;
}
static struct zspage *find_get_zspage(struct size_class *class)
{
int i;
struct zspage *zspage;
for (i = ZS_INUSE_RATIO_99; i >= ZS_INUSE_RATIO_0; i--) {
zspage = list_first_entry_or_null(&class->fullness_list[i],
struct zspage, list);
if (zspage)
break;
}
return zspage;
}
static inline int __zs_cpu_up(struct mapping_area *area)
{
/*
* Make sure we don't leak memory if a cpu UP notification
* and zs_init() race and both call zs_cpu_up() on the same cpu
*/
if (area->vm_buf)
return 0;
area->vm_buf = kmalloc(ZS_MAX_ALLOC_SIZE, GFP_KERNEL);
if (!area->vm_buf)
return -ENOMEM;
return 0;
}
static inline void __zs_cpu_down(struct mapping_area *area)
{
kfree(area->vm_buf);
area->vm_buf = NULL;
}
static void *__zs_map_object(struct mapping_area *area,
struct page *pages[2], int off, int size)
{
int sizes[2];
void *addr;
char *buf = area->vm_buf;
/* disable page faults to match kmap_atomic() return conditions */
pagefault_disable();
/* no read fastpath */
if (area->vm_mm == ZS_MM_WO)
goto out;
sizes[0] = PAGE_SIZE - off;
sizes[1] = size - sizes[0];
/* copy object to per-cpu buffer */
addr = kmap_atomic(pages[0]);
memcpy(buf, addr + off, sizes[0]);
kunmap_atomic(addr);
addr = kmap_atomic(pages[1]);
memcpy(buf + sizes[0], addr, sizes[1]);
kunmap_atomic(addr);
out:
return area->vm_buf;
}
static void __zs_unmap_object(struct mapping_area *area,
struct page *pages[2], int off, int size)
{
int sizes[2];
void *addr;
char *buf;
/* no write fastpath */
if (area->vm_mm == ZS_MM_RO)
goto out;
buf = area->vm_buf;
buf = buf + ZS_HANDLE_SIZE;
size -= ZS_HANDLE_SIZE;
off += ZS_HANDLE_SIZE;
sizes[0] = PAGE_SIZE - off;
sizes[1] = size - sizes[0];
/* copy per-cpu buffer to object */
addr = kmap_atomic(pages[0]);
memcpy(addr + off, buf, sizes[0]);
kunmap_atomic(addr);
addr = kmap_atomic(pages[1]);
memcpy(addr, buf + sizes[0], sizes[1]);
kunmap_atomic(addr);
out:
/* enable page faults to match kunmap_atomic() return conditions */
pagefault_enable();
}
static int zs_cpu_prepare(unsigned int cpu)
{
struct mapping_area *area;
area = &per_cpu(zs_map_area, cpu);
return __zs_cpu_up(area);
}
static int zs_cpu_dead(unsigned int cpu)
{
struct mapping_area *area;
area = &per_cpu(zs_map_area, cpu);
__zs_cpu_down(area);
return 0;
}
static bool can_merge(struct size_class *prev, int pages_per_zspage,
int objs_per_zspage)
{
if (prev->pages_per_zspage == pages_per_zspage &&
prev->objs_per_zspage == objs_per_zspage)
return true;
return false;
}
static bool zspage_full(struct size_class *class, struct zspage *zspage)
{
return get_zspage_inuse(zspage) == class->objs_per_zspage;
}
static bool zspage_empty(struct zspage *zspage)
{
return get_zspage_inuse(zspage) == 0;
}
/**
* zs_lookup_class_index() - Returns index of the zsmalloc &size_class
* that hold objects of the provided size.
* @pool: zsmalloc pool to use
* @size: object size
*
* Context: Any context.
*
* Return: the index of the zsmalloc &size_class that hold objects of the
* provided size.
*/
unsigned int zs_lookup_class_index(struct zs_pool *pool, unsigned int size)
{
struct size_class *class;
class = pool->size_class[get_size_class_index(size)];
return class->index;
}
EXPORT_SYMBOL_GPL(zs_lookup_class_index);
unsigned long zs_get_total_pages(struct zs_pool *pool)
{
return atomic_long_read(&pool->pages_allocated);
}
EXPORT_SYMBOL_GPL(zs_get_total_pages);
/**
* zs_map_object - get address of allocated object from handle.
* @pool: pool from which the object was allocated
* @handle: handle returned from zs_malloc
* @mm: mapping mode to use
*
* Before using an object allocated from zs_malloc, it must be mapped using
* this function. When done with the object, it must be unmapped using
* zs_unmap_object.
*
* Only one object can be mapped per cpu at a time. There is no protection
* against nested mappings.
*
* This function returns with preemption and page faults disabled.
*/
void *zs_map_object(struct zs_pool *pool, unsigned long handle,
enum zs_mapmode mm)
{
struct zspage *zspage;
struct page *page;
unsigned long obj, off;
unsigned int obj_idx;
struct size_class *class;
struct mapping_area *area;
struct page *pages[2];
void *ret;
/*
* Because we use per-cpu mapping areas shared among the
* pools/users, we can't allow mapping in interrupt context
* because it can corrupt another users mappings.
*/
BUG_ON(in_interrupt());
/* It guarantees it can get zspage from handle safely */
spin_lock(&pool->lock);
obj = handle_to_obj(handle);
obj_to_location(obj, &page, &obj_idx);
zspage = get_zspage(page);
/*
* migration cannot move any zpages in this zspage. Here, pool->lock
* is too heavy since callers would take some time until they calls
* zs_unmap_object API so delegate the locking from class to zspage
* which is smaller granularity.
*/
migrate_read_lock(zspage);
spin_unlock(&pool->lock);
class = zspage_class(pool, zspage);
off = offset_in_page(class->size * obj_idx);
local_lock(&zs_map_area.lock);
area = this_cpu_ptr(&zs_map_area);
area->vm_mm = mm;
if (off + class->size <= PAGE_SIZE) {
/* this object is contained entirely within a page */
area->vm_addr = kmap_atomic(page);
ret = area->vm_addr + off;
goto out;
}
/* this object spans two pages */
pages[0] = page;
pages[1] = get_next_page(page);
BUG_ON(!pages[1]);
ret = __zs_map_object(area, pages, off, class->size);
out:
if (likely(!ZsHugePage(zspage)))
ret += ZS_HANDLE_SIZE;
return ret;
}
EXPORT_SYMBOL_GPL(zs_map_object);
void zs_unmap_object(struct zs_pool *pool, unsigned long handle)
{
struct zspage *zspage;
struct page *page;
unsigned long obj, off;
unsigned int obj_idx;
struct size_class *class;
struct mapping_area *area;
obj = handle_to_obj(handle);
obj_to_location(obj, &page, &obj_idx);
zspage = get_zspage(page);
class = zspage_class(pool, zspage);
off = offset_in_page(class->size * obj_idx);
area = this_cpu_ptr(&zs_map_area);
if (off + class->size <= PAGE_SIZE)
kunmap_atomic(area->vm_addr);
else {
struct page *pages[2];
pages[0] = page;
pages[1] = get_next_page(page);
BUG_ON(!pages[1]);
__zs_unmap_object(area, pages, off, class->size);
}
local_unlock(&zs_map_area.lock);
migrate_read_unlock(zspage);
}
EXPORT_SYMBOL_GPL(zs_unmap_object);
/**
* zs_huge_class_size() - Returns the size (in bytes) of the first huge
* zsmalloc &size_class.
* @pool: zsmalloc pool to use
*
* The function returns the size of the first huge class - any object of equal
* or bigger size will be stored in zspage consisting of a single physical
* page.
*
* Context: Any context.
*
* Return: the size (in bytes) of the first huge zsmalloc &size_class.
*/
size_t zs_huge_class_size(struct zs_pool *pool)
{
return huge_class_size;
}
EXPORT_SYMBOL_GPL(zs_huge_class_size);
static unsigned long obj_malloc(struct zs_pool *pool,
struct zspage *zspage, unsigned long handle)
{
int i, nr_page, offset;
unsigned long obj;
struct link_free *link;
struct size_class *class;
struct page *m_page;
unsigned long m_offset;
void *vaddr;
class = pool->size_class[zspage->class];
handle |= OBJ_ALLOCATED_TAG;
obj = get_freeobj(zspage);
offset = obj * class->size;
nr_page = offset >> PAGE_SHIFT;
m_offset = offset_in_page(offset);
m_page = get_first_page(zspage);
for (i = 0; i < nr_page; i++)
m_page = get_next_page(m_page);
vaddr = kmap_atomic(m_page);
link = (struct link_free *)vaddr + m_offset / sizeof(*link);
set_freeobj(zspage, link->next >> OBJ_TAG_BITS);
if (likely(!ZsHugePage(zspage)))
/* record handle in the header of allocated chunk */
link->handle = handle;
else
/* record handle to page->index */
zspage->first_page->index = handle;
kunmap_atomic(vaddr);
mod_zspage_inuse(zspage, 1);
obj = location_to_obj(m_page, obj);
return obj;
}
/**
* zs_malloc - Allocate block of given size from pool.
* @pool: pool to allocate from
* @size: size of block to allocate
* @gfp: gfp flags when allocating object
*
* On success, handle to the allocated object is returned,
* otherwise an ERR_PTR().
* Allocation requests with size > ZS_MAX_ALLOC_SIZE will fail.
*/
unsigned long zs_malloc(struct zs_pool *pool, size_t size, gfp_t gfp)
{
unsigned long handle, obj;
struct size_class *class;
int newfg;
struct zspage *zspage;
if (unlikely(!size || size > ZS_MAX_ALLOC_SIZE))
return (unsigned long)ERR_PTR(-EINVAL);
handle = cache_alloc_handle(pool, gfp);
if (!handle)
return (unsigned long)ERR_PTR(-ENOMEM);
/* extra space in chunk to keep the handle */
size += ZS_HANDLE_SIZE;
class = pool->size_class[get_size_class_index(size)];
/* pool->lock effectively protects the zpage migration */
spin_lock(&pool->lock);
zspage = find_get_zspage(class);
if (likely(zspage)) {
obj = obj_malloc(pool, zspage, handle);
/* Now move the zspage to another fullness group, if required */
fix_fullness_group(class, zspage);
record_obj(handle, obj);
class_stat_inc(class, ZS_OBJS_INUSE, 1);
goto out;
}
spin_unlock(&pool->lock);
zspage = alloc_zspage(pool, class, gfp);
if (!zspage) {
cache_free_handle(pool, handle);
return (unsigned long)ERR_PTR(-ENOMEM);
}
spin_lock(&pool->lock);
obj = obj_malloc(pool, zspage, handle);
newfg = get_fullness_group(class, zspage);
insert_zspage(class, zspage, newfg);
set_zspage_mapping(zspage, class->index, newfg);
record_obj(handle, obj);
atomic_long_add(class->pages_per_zspage, &pool->pages_allocated);
class_stat_inc(class, ZS_OBJS_ALLOCATED, class->objs_per_zspage);
class_stat_inc(class, ZS_OBJS_INUSE, 1);
/* We completely set up zspage so mark them as movable */
SetZsPageMovable(pool, zspage);
out:
spin_unlock(&pool->lock);
return handle;
}
EXPORT_SYMBOL_GPL(zs_malloc);
static void obj_free(int class_size, unsigned long obj)
{
struct link_free *link;
struct zspage *zspage;
struct page *f_page;
unsigned long f_offset;
unsigned int f_objidx;
void *vaddr;
obj_to_location(obj, &f_page, &f_objidx);
f_offset = offset_in_page(class_size * f_objidx);
zspage = get_zspage(f_page);
vaddr = kmap_atomic(f_page);
link = (struct link_free *)(vaddr + f_offset);
/* Insert this object in containing zspage's freelist */
if (likely(!ZsHugePage(zspage)))
link->next = get_freeobj(zspage) << OBJ_TAG_BITS;
else
f_page->index = 0;
set_freeobj(zspage, f_objidx);
kunmap_atomic(vaddr);
mod_zspage_inuse(zspage, -1);
}
void zs_free(struct zs_pool *pool, unsigned long handle)
{
struct zspage *zspage;
struct page *f_page;
unsigned long obj;
struct size_class *class;
int fullness;
if (IS_ERR_OR_NULL((void *)handle))
return;
/*
* The pool->lock protects the race with zpage's migration
* so it's safe to get the page from handle.
*/
spin_lock(&pool->lock);
obj = handle_to_obj(handle);
obj_to_page(obj, &f_page);
zspage = get_zspage(f_page);
class = zspage_class(pool, zspage);
class_stat_dec(class, ZS_OBJS_INUSE, 1);
obj_free(class->size, obj);
fullness = fix_fullness_group(class, zspage);
if (fullness == ZS_INUSE_RATIO_0)
free_zspage(pool, class, zspage);
spin_unlock(&pool->lock);
cache_free_handle(pool, handle);
}
EXPORT_SYMBOL_GPL(zs_free);
static void zs_object_copy(struct size_class *class, unsigned long dst,
unsigned long src)
{
struct page *s_page, *d_page;
unsigned int s_objidx, d_objidx;
unsigned long s_off, d_off;
void *s_addr, *d_addr;
int s_size, d_size, size;
int written = 0;
s_size = d_size = class->size;
obj_to_location(src, &s_page, &s_objidx);
obj_to_location(dst, &d_page, &d_objidx);
s_off = offset_in_page(class->size * s_objidx);
d_off = offset_in_page(class->size * d_objidx);
if (s_off + class->size > PAGE_SIZE)
s_size = PAGE_SIZE - s_off;
if (d_off + class->size > PAGE_SIZE)
d_size = PAGE_SIZE - d_off;
s_addr = kmap_atomic(s_page);
d_addr = kmap_atomic(d_page);
while (1) {
size = min(s_size, d_size);
memcpy(d_addr + d_off, s_addr + s_off, size);
written += size;
if (written == class->size)
break;
s_off += size;
s_size -= size;
d_off += size;
d_size -= size;
/*
* Calling kunmap_atomic(d_addr) is necessary. kunmap_atomic()
* calls must occurs in reverse order of calls to kmap_atomic().
* So, to call kunmap_atomic(s_addr) we should first call
* kunmap_atomic(d_addr). For more details see
* Documentation/mm/highmem.rst.
*/
if (s_off >= PAGE_SIZE) {
kunmap_atomic(d_addr);
kunmap_atomic(s_addr);
s_page = get_next_page(s_page);
s_addr = kmap_atomic(s_page);
d_addr = kmap_atomic(d_page);
s_size = class->size - written;
s_off = 0;
}
if (d_off >= PAGE_SIZE) {
kunmap_atomic(d_addr);
d_page = get_next_page(d_page);
d_addr = kmap_atomic(d_page);
d_size = class->size - written;
d_off = 0;
}
}
kunmap_atomic(d_addr);
kunmap_atomic(s_addr);
}
/*
* Find alloced object in zspage from index object and
* return handle.
*/
static unsigned long find_alloced_obj(struct size_class *class,
struct page *page, int *obj_idx)
{
unsigned int offset;
int index = *obj_idx;
unsigned long handle = 0;
void *addr = kmap_atomic(page);
offset = get_first_obj_offset(page);
offset += class->size * index;
while (offset < PAGE_SIZE) {
if (obj_allocated(page, addr + offset, &handle))
break;
offset += class->size;
index++;
}
kunmap_atomic(addr);
*obj_idx = index;
return handle;
}
static void migrate_zspage(struct zs_pool *pool, struct zspage *src_zspage,
struct zspage *dst_zspage)
{
unsigned long used_obj, free_obj;
unsigned long handle;
int obj_idx = 0;
struct page *s_page = get_first_page(src_zspage);
struct size_class *class = pool->size_class[src_zspage->class];
while (1) {
handle = find_alloced_obj(class, s_page, &obj_idx);
if (!handle) {
s_page = get_next_page(s_page);
if (!s_page)
break;
obj_idx = 0;
continue;
}
used_obj = handle_to_obj(handle);
free_obj = obj_malloc(pool, dst_zspage, handle);
zs_object_copy(class, free_obj, used_obj);
obj_idx++;
record_obj(handle, free_obj);
obj_free(class->size, used_obj);
/* Stop if there is no more space */
if (zspage_full(class, dst_zspage))
break;
/* Stop if there are no more objects to migrate */
if (zspage_empty(src_zspage))
break;
}
}
static struct zspage *isolate_src_zspage(struct size_class *class)
{
struct zspage *zspage;
int fg;
for (fg = ZS_INUSE_RATIO_10; fg <= ZS_INUSE_RATIO_99; fg++) {
zspage = list_first_entry_or_null(&class->fullness_list[fg],
struct zspage, list);
if (zspage) {
remove_zspage(class, zspage, fg);
return zspage;
}
}
return zspage;
}
static struct zspage *isolate_dst_zspage(struct size_class *class)
{
struct zspage *zspage;
int fg;
for (fg = ZS_INUSE_RATIO_99; fg >= ZS_INUSE_RATIO_10; fg--) {
zspage = list_first_entry_or_null(&class->fullness_list[fg],
struct zspage, list);
if (zspage) {
remove_zspage(class, zspage, fg);
return zspage;
}
}
return zspage;
}
/*
* putback_zspage - add @zspage into right class's fullness list
* @class: destination class
* @zspage: target page
*
* Return @zspage's fullness status
*/
static int putback_zspage(struct size_class *class, struct zspage *zspage)
{
int fullness;
fullness = get_fullness_group(class, zspage);
insert_zspage(class, zspage, fullness);
set_zspage_mapping(zspage, class->index, fullness);
return fullness;
}
#ifdef CONFIG_COMPACTION
/*
* To prevent zspage destroy during migration, zspage freeing should
* hold locks of all pages in the zspage.
*/
static void lock_zspage(struct zspage *zspage)
{
struct page *curr_page, *page;
/*
* Pages we haven't locked yet can be migrated off the list while we're
* trying to lock them, so we need to be careful and only attempt to
* lock each page under migrate_read_lock(). Otherwise, the page we lock
* may no longer belong to the zspage. This means that we may wait for
* the wrong page to unlock, so we must take a reference to the page
* prior to waiting for it to unlock outside migrate_read_lock().
*/
while (1) {
migrate_read_lock(zspage);
page = get_first_page(zspage);
if (trylock_page(page))
break;
get_page(page);
migrate_read_unlock(zspage);
wait_on_page_locked(page);
put_page(page);
}
curr_page = page;
while ((page = get_next_page(curr_page))) {
if (trylock_page(page)) {
curr_page = page;
} else {
get_page(page);
migrate_read_unlock(zspage);
wait_on_page_locked(page);
put_page(page);
migrate_read_lock(zspage);
}
}
migrate_read_unlock(zspage);
}
#endif /* CONFIG_COMPACTION */
static void migrate_lock_init(struct zspage *zspage)
{
rwlock_init(&zspage->lock);
}
static void migrate_read_lock(struct zspage *zspage) __acquires(&zspage->lock)
{
read_lock(&zspage->lock);
}
static void migrate_read_unlock(struct zspage *zspage) __releases(&zspage->lock)
{
read_unlock(&zspage->lock);
}
#ifdef CONFIG_COMPACTION
static void migrate_write_lock(struct zspage *zspage)
{
write_lock(&zspage->lock);
}
static void migrate_write_lock_nested(struct zspage *zspage)
{
write_lock_nested(&zspage->lock, SINGLE_DEPTH_NESTING);
}
static void migrate_write_unlock(struct zspage *zspage)
{
write_unlock(&zspage->lock);
}
/* Number of isolated subpage for *page migration* in this zspage */
static void inc_zspage_isolation(struct zspage *zspage)
{
zspage->isolated++;
}
static void dec_zspage_isolation(struct zspage *zspage)
{
VM_BUG_ON(zspage->isolated == 0);
zspage->isolated--;
}
static const struct movable_operations zsmalloc_mops;
static void replace_sub_page(struct size_class *class, struct zspage *zspage,
struct page *newpage, struct page *oldpage)
{
struct page *page;
struct page *pages[ZS_MAX_PAGES_PER_ZSPAGE] = {NULL, };
int idx = 0;
page = get_first_page(zspage);
do {
if (page == oldpage)
pages[idx] = newpage;
else
pages[idx] = page;
idx++;
} while ((page = get_next_page(page)) != NULL);
create_page_chain(class, zspage, pages);
set_first_obj_offset(newpage, get_first_obj_offset(oldpage));
if (unlikely(ZsHugePage(zspage)))
newpage->index = oldpage->index;
__SetPageMovable(newpage, &zsmalloc_mops);
}
static bool zs_page_isolate(struct page *page, isolate_mode_t mode)
{
struct zs_pool *pool;
struct zspage *zspage;
/*
* Page is locked so zspage couldn't be destroyed. For detail, look at
* lock_zspage in free_zspage.
*/
VM_BUG_ON_PAGE(PageIsolated(page), page);
zspage = get_zspage(page);
pool = zspage->pool;
spin_lock(&pool->lock);
inc_zspage_isolation(zspage);
spin_unlock(&pool->lock);
return true;
}
static int zs_page_migrate(struct page *newpage, struct page *page,
enum migrate_mode mode)
{
struct zs_pool *pool;
struct size_class *class;
struct zspage *zspage;
struct page *dummy;
void *s_addr, *d_addr, *addr;
unsigned int offset;
unsigned long handle;
unsigned long old_obj, new_obj;
unsigned int obj_idx;
/*
* We cannot support the _NO_COPY case here, because copy needs to
* happen under the zs lock, which does not work with
* MIGRATE_SYNC_NO_COPY workflow.
*/
if (mode == MIGRATE_SYNC_NO_COPY)
return -EINVAL;
VM_BUG_ON_PAGE(!PageIsolated(page), page);
/* The page is locked, so this pointer must remain valid */
zspage = get_zspage(page);
pool = zspage->pool;
/*
* The pool's lock protects the race between zpage migration
* and zs_free.
*/
spin_lock(&pool->lock);
class = zspage_class(pool, zspage);
/* the migrate_write_lock protects zpage access via zs_map_object */
migrate_write_lock(zspage);
offset = get_first_obj_offset(page);
s_addr = kmap_atomic(page);
/*
* Here, any user cannot access all objects in the zspage so let's move.
*/
d_addr = kmap_atomic(newpage);
memcpy(d_addr, s_addr, PAGE_SIZE);
kunmap_atomic(d_addr);
for (addr = s_addr + offset; addr < s_addr + PAGE_SIZE;
addr += class->size) {
if (obj_allocated(page, addr, &handle)) {
old_obj = handle_to_obj(handle);
obj_to_location(old_obj, &dummy, &obj_idx);
new_obj = (unsigned long)location_to_obj(newpage,
obj_idx);
record_obj(handle, new_obj);
}
}
kunmap_atomic(s_addr);
replace_sub_page(class, zspage, newpage, page);
dec_zspage_isolation(zspage);
/*
* Since we complete the data copy and set up new zspage structure,
* it's okay to release the pool's lock.
*/
spin_unlock(&pool->lock);
migrate_write_unlock(zspage);
get_page(newpage);
if (page_zone(newpage) != page_zone(page)) {
dec_zone_page_state(page, NR_ZSPAGES);
inc_zone_page_state(newpage, NR_ZSPAGES);
}
reset_page(page);
put_page(page);
return MIGRATEPAGE_SUCCESS;
}
static void zs_page_putback(struct page *page)
{
struct zs_pool *pool;
struct zspage *zspage;
VM_BUG_ON_PAGE(!PageIsolated(page), page);
zspage = get_zspage(page);
pool = zspage->pool;
spin_lock(&pool->lock);
dec_zspage_isolation(zspage);
spin_unlock(&pool->lock);
}
static const struct movable_operations zsmalloc_mops = {
.isolate_page = zs_page_isolate,
.migrate_page = zs_page_migrate,
.putback_page = zs_page_putback,
};
/*
* Caller should hold page_lock of all pages in the zspage
* In here, we cannot use zspage meta data.
*/
static void async_free_zspage(struct work_struct *work)
{
int i;
struct size_class *class;
unsigned int class_idx;
int fullness;
struct zspage *zspage, *tmp;
LIST_HEAD(free_pages);
struct zs_pool *pool = container_of(work, struct zs_pool,
free_work);
for (i = 0; i < ZS_SIZE_CLASSES; i++) {
class = pool->size_class[i];
if (class->index != i)
continue;
spin_lock(&pool->lock);
list_splice_init(&class->fullness_list[ZS_INUSE_RATIO_0],
&free_pages);
spin_unlock(&pool->lock);
}
list_for_each_entry_safe(zspage, tmp, &free_pages, list) {
list_del(&zspage->list);
lock_zspage(zspage);
get_zspage_mapping(zspage, &class_idx, &fullness);
VM_BUG_ON(fullness != ZS_INUSE_RATIO_0);
class = pool->size_class[class_idx];
spin_lock(&pool->lock);
__free_zspage(pool, class, zspage);
spin_unlock(&pool->lock);
}
};
static void kick_deferred_free(struct zs_pool *pool)
{
schedule_work(&pool->free_work);
}
static void zs_flush_migration(struct zs_pool *pool)
{
flush_work(&pool->free_work);
}
static void init_deferred_free(struct zs_pool *pool)
{
INIT_WORK(&pool->free_work, async_free_zspage);
}
static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage)
{
struct page *page = get_first_page(zspage);
do {
WARN_ON(!trylock_page(page));
__SetPageMovable(page, &zsmalloc_mops);
unlock_page(page);
} while ((page = get_next_page(page)) != NULL);
}
#else
static inline void zs_flush_migration(struct zs_pool *pool) { }
#endif
/*
*
* Based on the number of unused allocated objects calculate
* and return the number of pages that we can free.
*/
static unsigned long zs_can_compact(struct size_class *class)
{
unsigned long obj_wasted;
unsigned long obj_allocated = zs_stat_get(class, ZS_OBJS_ALLOCATED);
unsigned long obj_used = zs_stat_get(class, ZS_OBJS_INUSE);
if (obj_allocated <= obj_used)
return 0;
obj_wasted = obj_allocated - obj_used;
obj_wasted /= class->objs_per_zspage;
return obj_wasted * class->pages_per_zspage;
}
static unsigned long __zs_compact(struct zs_pool *pool,
struct size_class *class)
{
struct zspage *src_zspage = NULL;
struct zspage *dst_zspage = NULL;
unsigned long pages_freed = 0;
/*
* protect the race between zpage migration and zs_free
* as well as zpage allocation/free
*/
spin_lock(&pool->lock);
while (zs_can_compact(class)) {
int fg;
if (!dst_zspage) {
dst_zspage = isolate_dst_zspage(class);
if (!dst_zspage)
break;
migrate_write_lock(dst_zspage);
}
src_zspage = isolate_src_zspage(class);
if (!src_zspage)
break;
migrate_write_lock_nested(src_zspage);
migrate_zspage(pool, src_zspage, dst_zspage);
fg = putback_zspage(class, src_zspage);
migrate_write_unlock(src_zspage);
if (fg == ZS_INUSE_RATIO_0) {
free_zspage(pool, class, src_zspage);
pages_freed += class->pages_per_zspage;
}
src_zspage = NULL;
if (get_fullness_group(class, dst_zspage) == ZS_INUSE_RATIO_100
|| spin_is_contended(&pool->lock)) {
putback_zspage(class, dst_zspage);
migrate_write_unlock(dst_zspage);
dst_zspage = NULL;
spin_unlock(&pool->lock);
cond_resched();
spin_lock(&pool->lock);
}
}
if (src_zspage) {
putback_zspage(class, src_zspage);
migrate_write_unlock(src_zspage);
}
if (dst_zspage) {
putback_zspage(class, dst_zspage);
migrate_write_unlock(dst_zspage);
}
spin_unlock(&pool->lock);
return pages_freed;
}
unsigned long zs_compact(struct zs_pool *pool)
{
int i;
struct size_class *class;
unsigned long pages_freed = 0;
/*
* Pool compaction is performed under pool->lock so it is basically
* single-threaded. Having more than one thread in __zs_compact()
* will increase pool->lock contention, which will impact other
* zsmalloc operations that need pool->lock.
*/
if (atomic_xchg(&pool->compaction_in_progress, 1))
return 0;
for (i = ZS_SIZE_CLASSES - 1; i >= 0; i--) {
class = pool->size_class[i];
if (class->index != i)
continue;
pages_freed += __zs_compact(pool, class);
}
atomic_long_add(pages_freed, &pool->stats.pages_compacted);
atomic_set(&pool->compaction_in_progress, 0);
return pages_freed;
}
EXPORT_SYMBOL_GPL(zs_compact);
void zs_pool_stats(struct zs_pool *pool, struct zs_pool_stats *stats)
{
memcpy(stats, &pool->stats, sizeof(struct zs_pool_stats));
}
EXPORT_SYMBOL_GPL(zs_pool_stats);
static unsigned long zs_shrinker_scan(struct shrinker *shrinker,
struct shrink_control *sc)
{
unsigned long pages_freed;
struct zs_pool *pool = container_of(shrinker, struct zs_pool,
shrinker);
/*
* Compact classes and calculate compaction delta.
* Can run concurrently with a manually triggered
* (by user) compaction.
*/
pages_freed = zs_compact(pool);
return pages_freed ? pages_freed : SHRINK_STOP;
}
static unsigned long zs_shrinker_count(struct shrinker *shrinker,
struct shrink_control *sc)
{
int i;
struct size_class *class;
unsigned long pages_to_free = 0;
struct zs_pool *pool = container_of(shrinker, struct zs_pool,
shrinker);
for (i = ZS_SIZE_CLASSES - 1; i >= 0; i--) {
class = pool->size_class[i];
if (class->index != i)
continue;
pages_to_free += zs_can_compact(class);
}
return pages_to_free;
}
static void zs_unregister_shrinker(struct zs_pool *pool)
{
unregister_shrinker(&pool->shrinker);
}
static int zs_register_shrinker(struct zs_pool *pool)
{
pool->shrinker.scan_objects = zs_shrinker_scan;
pool->shrinker.count_objects = zs_shrinker_count;
pool->shrinker.batch = 0;
pool->shrinker.seeks = DEFAULT_SEEKS;
return register_shrinker(&pool->shrinker, "mm-zspool:%s",
pool->name);
}
static int calculate_zspage_chain_size(int class_size)
{
int i, min_waste = INT_MAX;
int chain_size = 1;
if (is_power_of_2(class_size))
return chain_size;
for (i = 1; i <= ZS_MAX_PAGES_PER_ZSPAGE; i++) {
int waste;
waste = (i * PAGE_SIZE) % class_size;
if (waste < min_waste) {
min_waste = waste;
chain_size = i;
}
}
return chain_size;
}
/**
* zs_create_pool - Creates an allocation pool to work from.
* @name: pool name to be created
*
* This function must be called before anything when using
* the zsmalloc allocator.
*
* On success, a pointer to the newly created pool is returned,
* otherwise NULL.
*/
struct zs_pool *zs_create_pool(const char *name)
{
int i;
struct zs_pool *pool;
struct size_class *prev_class = NULL;
pool = kzalloc(sizeof(*pool), GFP_KERNEL);
if (!pool)
return NULL;
init_deferred_free(pool);
spin_lock_init(&pool->lock);
atomic_set(&pool->compaction_in_progress, 0);
pool->name = kstrdup(name, GFP_KERNEL);
if (!pool->name)
goto err;
if (create_cache(pool))
goto err;
/*
* Iterate reversely, because, size of size_class that we want to use
* for merging should be larger or equal to current size.
*/
for (i = ZS_SIZE_CLASSES - 1; i >= 0; i--) {
int size;
int pages_per_zspage;
int objs_per_zspage;
struct size_class *class;
int fullness;
size = ZS_MIN_ALLOC_SIZE + i * ZS_SIZE_CLASS_DELTA;
if (size > ZS_MAX_ALLOC_SIZE)
size = ZS_MAX_ALLOC_SIZE;
pages_per_zspage = calculate_zspage_chain_size(size);
objs_per_zspage = pages_per_zspage * PAGE_SIZE / size;
/*
* We iterate from biggest down to smallest classes,
* so huge_class_size holds the size of the first huge
* class. Any object bigger than or equal to that will
* endup in the huge class.
*/
if (pages_per_zspage != 1 && objs_per_zspage != 1 &&
!huge_class_size) {
huge_class_size = size;
/*
* The object uses ZS_HANDLE_SIZE bytes to store the
* handle. We need to subtract it, because zs_malloc()
* unconditionally adds handle size before it performs
* size class search - so object may be smaller than
* huge class size, yet it still can end up in the huge
* class because it grows by ZS_HANDLE_SIZE extra bytes
* right before class lookup.
*/
huge_class_size -= (ZS_HANDLE_SIZE - 1);
}
/*
* size_class is used for normal zsmalloc operation such
* as alloc/free for that size. Although it is natural that we
* have one size_class for each size, there is a chance that we
* can get more memory utilization if we use one size_class for
* many different sizes whose size_class have same
* characteristics. So, we makes size_class point to
* previous size_class if possible.
*/
if (prev_class) {
if (can_merge(prev_class, pages_per_zspage, objs_per_zspage)) {
pool->size_class[i] = prev_class;
continue;
}
}
class = kzalloc(sizeof(struct size_class), GFP_KERNEL);
if (!class)
goto err;
class->size = size;
class->index = i;
class->pages_per_zspage = pages_per_zspage;
class->objs_per_zspage = objs_per_zspage;
pool->size_class[i] = class;
fullness = ZS_INUSE_RATIO_0;
while (fullness < NR_FULLNESS_GROUPS) {
INIT_LIST_HEAD(&class->fullness_list[fullness]);
fullness++;
}
prev_class = class;
}
/* debug only, don't abort if it fails */
zs_pool_stat_create(pool, name);
/*
* Not critical since shrinker is only used to trigger internal
* defragmentation of the pool which is pretty optional thing. If
* registration fails we still can use the pool normally and user can
* trigger compaction manually. Thus, ignore return code.
*/
zs_register_shrinker(pool);
return pool;
err:
zs_destroy_pool(pool);
return NULL;
}
EXPORT_SYMBOL_GPL(zs_create_pool);
void zs_destroy_pool(struct zs_pool *pool)
{
int i;
zs_unregister_shrinker(pool);
zs_flush_migration(pool);
zs_pool_stat_destroy(pool);
for (i = 0; i < ZS_SIZE_CLASSES; i++) {
int fg;
struct size_class *class = pool->size_class[i];
if (!class)
continue;
if (class->index != i)
continue;
for (fg = ZS_INUSE_RATIO_0; fg < NR_FULLNESS_GROUPS; fg++) {
if (list_empty(&class->fullness_list[fg]))
continue;
pr_err("Class-%d fullness group %d is not empty\n",
class->size, fg);
}
kfree(class);
}
destroy_cache(pool);
kfree(pool->name);
kfree(pool);
}
EXPORT_SYMBOL_GPL(zs_destroy_pool);
static int __init zs_init(void)
{
int ret;
ret = cpuhp_setup_state(CPUHP_MM_ZS_PREPARE, "mm/zsmalloc:prepare",
zs_cpu_prepare, zs_cpu_dead);
if (ret)
goto out;
#ifdef CONFIG_ZPOOL
zpool_register_driver(&zs_zpool_driver);
#endif
zs_stat_init();
return 0;
out:
return ret;
}
static void __exit zs_exit(void)
{
#ifdef CONFIG_ZPOOL
zpool_unregister_driver(&zs_zpool_driver);
#endif
cpuhp_remove_state(CPUHP_MM_ZS_PREPARE);
zs_stat_exit();
}
module_init(zs_init);
module_exit(zs_exit);
MODULE_LICENSE("Dual BSD/GPL");
MODULE_AUTHOR("Nitin Gupta <[email protected]>");
| linux-master | mm/zsmalloc.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* mm/kmemleak.c
*
* Copyright (C) 2008 ARM Limited
* Written by Catalin Marinas <[email protected]>
*
* For more information on the algorithm and kmemleak usage, please see
* Documentation/dev-tools/kmemleak.rst.
*
* Notes on locking
* ----------------
*
* The following locks and mutexes are used by kmemleak:
*
* - kmemleak_lock (raw_spinlock_t): protects the object_list as well as
* del_state modifications and accesses to the object_tree_root (or
* object_phys_tree_root). The object_list is the main list holding the
* metadata (struct kmemleak_object) for the allocated memory blocks.
* The object_tree_root and object_phys_tree_root are red
* black trees used to look-up metadata based on a pointer to the
* corresponding memory block. The object_phys_tree_root is for objects
* allocated with physical address. The kmemleak_object structures are
* added to the object_list and object_tree_root (or object_phys_tree_root)
* in the create_object() function called from the kmemleak_alloc() (or
* kmemleak_alloc_phys()) callback and removed in delete_object() called from
* the kmemleak_free() callback
* - kmemleak_object.lock (raw_spinlock_t): protects a kmemleak_object.
* Accesses to the metadata (e.g. count) are protected by this lock. Note
* that some members of this structure may be protected by other means
* (atomic or kmemleak_lock). This lock is also held when scanning the
* corresponding memory block to avoid the kernel freeing it via the
* kmemleak_free() callback. This is less heavyweight than holding a global
* lock like kmemleak_lock during scanning.
* - scan_mutex (mutex): ensures that only one thread may scan the memory for
* unreferenced objects at a time. The gray_list contains the objects which
* are already referenced or marked as false positives and need to be
* scanned. This list is only modified during a scanning episode when the
* scan_mutex is held. At the end of a scan, the gray_list is always empty.
* Note that the kmemleak_object.use_count is incremented when an object is
* added to the gray_list and therefore cannot be freed. This mutex also
* prevents multiple users of the "kmemleak" debugfs file together with
* modifications to the memory scanning parameters including the scan_thread
* pointer
*
* Locks and mutexes are acquired/nested in the following order:
*
* scan_mutex [-> object->lock] -> kmemleak_lock -> other_object->lock (SINGLE_DEPTH_NESTING)
*
* No kmemleak_lock and object->lock nesting is allowed outside scan_mutex
* regions.
*
* The kmemleak_object structures have a use_count incremented or decremented
* using the get_object()/put_object() functions. When the use_count becomes
* 0, this count can no longer be incremented and put_object() schedules the
* kmemleak_object freeing via an RCU callback. All calls to the get_object()
* function must be protected by rcu_read_lock() to avoid accessing a freed
* structure.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/sched/signal.h>
#include <linux/sched/task.h>
#include <linux/sched/task_stack.h>
#include <linux/jiffies.h>
#include <linux/delay.h>
#include <linux/export.h>
#include <linux/kthread.h>
#include <linux/rbtree.h>
#include <linux/fs.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/cpumask.h>
#include <linux/spinlock.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/rcupdate.h>
#include <linux/stacktrace.h>
#include <linux/stackdepot.h>
#include <linux/cache.h>
#include <linux/percpu.h>
#include <linux/memblock.h>
#include <linux/pfn.h>
#include <linux/mmzone.h>
#include <linux/slab.h>
#include <linux/thread_info.h>
#include <linux/err.h>
#include <linux/uaccess.h>
#include <linux/string.h>
#include <linux/nodemask.h>
#include <linux/mm.h>
#include <linux/workqueue.h>
#include <linux/crc32.h>
#include <asm/sections.h>
#include <asm/processor.h>
#include <linux/atomic.h>
#include <linux/kasan.h>
#include <linux/kfence.h>
#include <linux/kmemleak.h>
#include <linux/memory_hotplug.h>
/*
* Kmemleak configuration and common defines.
*/
#define MAX_TRACE 16 /* stack trace length */
#define MSECS_MIN_AGE 5000 /* minimum object age for reporting */
#define SECS_FIRST_SCAN 60 /* delay before the first scan */
#define SECS_SCAN_WAIT 600 /* subsequent auto scanning delay */
#define MAX_SCAN_SIZE 4096 /* maximum size of a scanned block */
#define BYTES_PER_POINTER sizeof(void *)
/* GFP bitmask for kmemleak internal allocations */
#define gfp_kmemleak_mask(gfp) (((gfp) & (GFP_KERNEL | GFP_ATOMIC | \
__GFP_NOLOCKDEP)) | \
__GFP_NORETRY | __GFP_NOMEMALLOC | \
__GFP_NOWARN)
/* scanning area inside a memory block */
struct kmemleak_scan_area {
struct hlist_node node;
unsigned long start;
size_t size;
};
#define KMEMLEAK_GREY 0
#define KMEMLEAK_BLACK -1
/*
* Structure holding the metadata for each allocated memory block.
* Modifications to such objects should be made while holding the
* object->lock. Insertions or deletions from object_list, gray_list or
* rb_node are already protected by the corresponding locks or mutex (see
* the notes on locking above). These objects are reference-counted
* (use_count) and freed using the RCU mechanism.
*/
struct kmemleak_object {
raw_spinlock_t lock;
unsigned int flags; /* object status flags */
struct list_head object_list;
struct list_head gray_list;
struct rb_node rb_node;
struct rcu_head rcu; /* object_list lockless traversal */
/* object usage count; object freed when use_count == 0 */
atomic_t use_count;
unsigned int del_state; /* deletion state */
unsigned long pointer;
size_t size;
/* pass surplus references to this pointer */
unsigned long excess_ref;
/* minimum number of a pointers found before it is considered leak */
int min_count;
/* the total number of pointers found pointing to this object */
int count;
/* checksum for detecting modified objects */
u32 checksum;
/* memory ranges to be scanned inside an object (empty for all) */
struct hlist_head area_list;
depot_stack_handle_t trace_handle;
unsigned long jiffies; /* creation timestamp */
pid_t pid; /* pid of the current task */
char comm[TASK_COMM_LEN]; /* executable name */
};
/* flag representing the memory block allocation status */
#define OBJECT_ALLOCATED (1 << 0)
/* flag set after the first reporting of an unreference object */
#define OBJECT_REPORTED (1 << 1)
/* flag set to not scan the object */
#define OBJECT_NO_SCAN (1 << 2)
/* flag set to fully scan the object when scan_area allocation failed */
#define OBJECT_FULL_SCAN (1 << 3)
/* flag set for object allocated with physical address */
#define OBJECT_PHYS (1 << 4)
/* set when __remove_object() called */
#define DELSTATE_REMOVED (1 << 0)
/* set to temporarily prevent deletion from object_list */
#define DELSTATE_NO_DELETE (1 << 1)
#define HEX_PREFIX " "
/* number of bytes to print per line; must be 16 or 32 */
#define HEX_ROW_SIZE 16
/* number of bytes to print at a time (1, 2, 4, 8) */
#define HEX_GROUP_SIZE 1
/* include ASCII after the hex output */
#define HEX_ASCII 1
/* max number of lines to be printed */
#define HEX_MAX_LINES 2
/* the list of all allocated objects */
static LIST_HEAD(object_list);
/* the list of gray-colored objects (see color_gray comment below) */
static LIST_HEAD(gray_list);
/* memory pool allocation */
static struct kmemleak_object mem_pool[CONFIG_DEBUG_KMEMLEAK_MEM_POOL_SIZE];
static int mem_pool_free_count = ARRAY_SIZE(mem_pool);
static LIST_HEAD(mem_pool_free_list);
/* search tree for object boundaries */
static struct rb_root object_tree_root = RB_ROOT;
/* search tree for object (with OBJECT_PHYS flag) boundaries */
static struct rb_root object_phys_tree_root = RB_ROOT;
/* protecting the access to object_list, object_tree_root (or object_phys_tree_root) */
static DEFINE_RAW_SPINLOCK(kmemleak_lock);
/* allocation caches for kmemleak internal data */
static struct kmem_cache *object_cache;
static struct kmem_cache *scan_area_cache;
/* set if tracing memory operations is enabled */
static int kmemleak_enabled = 1;
/* same as above but only for the kmemleak_free() callback */
static int kmemleak_free_enabled = 1;
/* set in the late_initcall if there were no errors */
static int kmemleak_late_initialized;
/* set if a kmemleak warning was issued */
static int kmemleak_warning;
/* set if a fatal kmemleak error has occurred */
static int kmemleak_error;
/* minimum and maximum address that may be valid pointers */
static unsigned long min_addr = ULONG_MAX;
static unsigned long max_addr;
static struct task_struct *scan_thread;
/* used to avoid reporting of recently allocated objects */
static unsigned long jiffies_min_age;
static unsigned long jiffies_last_scan;
/* delay between automatic memory scannings */
static unsigned long jiffies_scan_wait;
/* enables or disables the task stacks scanning */
static int kmemleak_stack_scan = 1;
/* protects the memory scanning, parameters and debug/kmemleak file access */
static DEFINE_MUTEX(scan_mutex);
/* setting kmemleak=on, will set this var, skipping the disable */
static int kmemleak_skip_disable;
/* If there are leaks that can be reported */
static bool kmemleak_found_leaks;
static bool kmemleak_verbose;
module_param_named(verbose, kmemleak_verbose, bool, 0600);
static void kmemleak_disable(void);
/*
* Print a warning and dump the stack trace.
*/
#define kmemleak_warn(x...) do { \
pr_warn(x); \
dump_stack(); \
kmemleak_warning = 1; \
} while (0)
/*
* Macro invoked when a serious kmemleak condition occurred and cannot be
* recovered from. Kmemleak will be disabled and further allocation/freeing
* tracing no longer available.
*/
#define kmemleak_stop(x...) do { \
kmemleak_warn(x); \
kmemleak_disable(); \
} while (0)
#define warn_or_seq_printf(seq, fmt, ...) do { \
if (seq) \
seq_printf(seq, fmt, ##__VA_ARGS__); \
else \
pr_warn(fmt, ##__VA_ARGS__); \
} while (0)
static void warn_or_seq_hex_dump(struct seq_file *seq, int prefix_type,
int rowsize, int groupsize, const void *buf,
size_t len, bool ascii)
{
if (seq)
seq_hex_dump(seq, HEX_PREFIX, prefix_type, rowsize, groupsize,
buf, len, ascii);
else
print_hex_dump(KERN_WARNING, pr_fmt(HEX_PREFIX), prefix_type,
rowsize, groupsize, buf, len, ascii);
}
/*
* Printing of the objects hex dump to the seq file. The number of lines to be
* printed is limited to HEX_MAX_LINES to prevent seq file spamming. The
* actual number of printed bytes depends on HEX_ROW_SIZE. It must be called
* with the object->lock held.
*/
static void hex_dump_object(struct seq_file *seq,
struct kmemleak_object *object)
{
const u8 *ptr = (const u8 *)object->pointer;
size_t len;
if (WARN_ON_ONCE(object->flags & OBJECT_PHYS))
return;
/* limit the number of lines to HEX_MAX_LINES */
len = min_t(size_t, object->size, HEX_MAX_LINES * HEX_ROW_SIZE);
warn_or_seq_printf(seq, " hex dump (first %zu bytes):\n", len);
kasan_disable_current();
warn_or_seq_hex_dump(seq, DUMP_PREFIX_NONE, HEX_ROW_SIZE,
HEX_GROUP_SIZE, kasan_reset_tag((void *)ptr), len, HEX_ASCII);
kasan_enable_current();
}
/*
* Object colors, encoded with count and min_count:
* - white - orphan object, not enough references to it (count < min_count)
* - gray - not orphan, not marked as false positive (min_count == 0) or
* sufficient references to it (count >= min_count)
* - black - ignore, it doesn't contain references (e.g. text section)
* (min_count == -1). No function defined for this color.
* Newly created objects don't have any color assigned (object->count == -1)
* before the next memory scan when they become white.
*/
static bool color_white(const struct kmemleak_object *object)
{
return object->count != KMEMLEAK_BLACK &&
object->count < object->min_count;
}
static bool color_gray(const struct kmemleak_object *object)
{
return object->min_count != KMEMLEAK_BLACK &&
object->count >= object->min_count;
}
/*
* Objects are considered unreferenced only if their color is white, they have
* not be deleted and have a minimum age to avoid false positives caused by
* pointers temporarily stored in CPU registers.
*/
static bool unreferenced_object(struct kmemleak_object *object)
{
return (color_white(object) && object->flags & OBJECT_ALLOCATED) &&
time_before_eq(object->jiffies + jiffies_min_age,
jiffies_last_scan);
}
/*
* Printing of the unreferenced objects information to the seq file. The
* print_unreferenced function must be called with the object->lock held.
*/
static void print_unreferenced(struct seq_file *seq,
struct kmemleak_object *object)
{
int i;
unsigned long *entries;
unsigned int nr_entries;
unsigned int msecs_age = jiffies_to_msecs(jiffies - object->jiffies);
nr_entries = stack_depot_fetch(object->trace_handle, &entries);
warn_or_seq_printf(seq, "unreferenced object 0x%08lx (size %zu):\n",
object->pointer, object->size);
warn_or_seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu (age %d.%03ds)\n",
object->comm, object->pid, object->jiffies,
msecs_age / 1000, msecs_age % 1000);
hex_dump_object(seq, object);
warn_or_seq_printf(seq, " backtrace:\n");
for (i = 0; i < nr_entries; i++) {
void *ptr = (void *)entries[i];
warn_or_seq_printf(seq, " [<%pK>] %pS\n", ptr, ptr);
}
}
/*
* Print the kmemleak_object information. This function is used mainly for
* debugging special cases when kmemleak operations. It must be called with
* the object->lock held.
*/
static void dump_object_info(struct kmemleak_object *object)
{
pr_notice("Object 0x%08lx (size %zu):\n",
object->pointer, object->size);
pr_notice(" comm \"%s\", pid %d, jiffies %lu\n",
object->comm, object->pid, object->jiffies);
pr_notice(" min_count = %d\n", object->min_count);
pr_notice(" count = %d\n", object->count);
pr_notice(" flags = 0x%x\n", object->flags);
pr_notice(" checksum = %u\n", object->checksum);
pr_notice(" backtrace:\n");
if (object->trace_handle)
stack_depot_print(object->trace_handle);
}
/*
* Look-up a memory block metadata (kmemleak_object) in the object search
* tree based on a pointer value. If alias is 0, only values pointing to the
* beginning of the memory block are allowed. The kmemleak_lock must be held
* when calling this function.
*/
static struct kmemleak_object *__lookup_object(unsigned long ptr, int alias,
bool is_phys)
{
struct rb_node *rb = is_phys ? object_phys_tree_root.rb_node :
object_tree_root.rb_node;
unsigned long untagged_ptr = (unsigned long)kasan_reset_tag((void *)ptr);
while (rb) {
struct kmemleak_object *object;
unsigned long untagged_objp;
object = rb_entry(rb, struct kmemleak_object, rb_node);
untagged_objp = (unsigned long)kasan_reset_tag((void *)object->pointer);
if (untagged_ptr < untagged_objp)
rb = object->rb_node.rb_left;
else if (untagged_objp + object->size <= untagged_ptr)
rb = object->rb_node.rb_right;
else if (untagged_objp == untagged_ptr || alias)
return object;
else {
kmemleak_warn("Found object by alias at 0x%08lx\n",
ptr);
dump_object_info(object);
break;
}
}
return NULL;
}
/* Look-up a kmemleak object which allocated with virtual address. */
static struct kmemleak_object *lookup_object(unsigned long ptr, int alias)
{
return __lookup_object(ptr, alias, false);
}
/*
* Increment the object use_count. Return 1 if successful or 0 otherwise. Note
* that once an object's use_count reached 0, the RCU freeing was already
* registered and the object should no longer be used. This function must be
* called under the protection of rcu_read_lock().
*/
static int get_object(struct kmemleak_object *object)
{
return atomic_inc_not_zero(&object->use_count);
}
/*
* Memory pool allocation and freeing. kmemleak_lock must not be held.
*/
static struct kmemleak_object *mem_pool_alloc(gfp_t gfp)
{
unsigned long flags;
struct kmemleak_object *object;
/* try the slab allocator first */
if (object_cache) {
object = kmem_cache_alloc(object_cache, gfp_kmemleak_mask(gfp));
if (object)
return object;
}
/* slab allocation failed, try the memory pool */
raw_spin_lock_irqsave(&kmemleak_lock, flags);
object = list_first_entry_or_null(&mem_pool_free_list,
typeof(*object), object_list);
if (object)
list_del(&object->object_list);
else if (mem_pool_free_count)
object = &mem_pool[--mem_pool_free_count];
else
pr_warn_once("Memory pool empty, consider increasing CONFIG_DEBUG_KMEMLEAK_MEM_POOL_SIZE\n");
raw_spin_unlock_irqrestore(&kmemleak_lock, flags);
return object;
}
/*
* Return the object to either the slab allocator or the memory pool.
*/
static void mem_pool_free(struct kmemleak_object *object)
{
unsigned long flags;
if (object < mem_pool || object >= mem_pool + ARRAY_SIZE(mem_pool)) {
kmem_cache_free(object_cache, object);
return;
}
/* add the object to the memory pool free list */
raw_spin_lock_irqsave(&kmemleak_lock, flags);
list_add(&object->object_list, &mem_pool_free_list);
raw_spin_unlock_irqrestore(&kmemleak_lock, flags);
}
/*
* RCU callback to free a kmemleak_object.
*/
static void free_object_rcu(struct rcu_head *rcu)
{
struct hlist_node *tmp;
struct kmemleak_scan_area *area;
struct kmemleak_object *object =
container_of(rcu, struct kmemleak_object, rcu);
/*
* Once use_count is 0 (guaranteed by put_object), there is no other
* code accessing this object, hence no need for locking.
*/
hlist_for_each_entry_safe(area, tmp, &object->area_list, node) {
hlist_del(&area->node);
kmem_cache_free(scan_area_cache, area);
}
mem_pool_free(object);
}
/*
* Decrement the object use_count. Once the count is 0, free the object using
* an RCU callback. Since put_object() may be called via the kmemleak_free() ->
* delete_object() path, the delayed RCU freeing ensures that there is no
* recursive call to the kernel allocator. Lock-less RCU object_list traversal
* is also possible.
*/
static void put_object(struct kmemleak_object *object)
{
if (!atomic_dec_and_test(&object->use_count))
return;
/* should only get here after delete_object was called */
WARN_ON(object->flags & OBJECT_ALLOCATED);
/*
* It may be too early for the RCU callbacks, however, there is no
* concurrent object_list traversal when !object_cache and all objects
* came from the memory pool. Free the object directly.
*/
if (object_cache)
call_rcu(&object->rcu, free_object_rcu);
else
free_object_rcu(&object->rcu);
}
/*
* Look up an object in the object search tree and increase its use_count.
*/
static struct kmemleak_object *__find_and_get_object(unsigned long ptr, int alias,
bool is_phys)
{
unsigned long flags;
struct kmemleak_object *object;
rcu_read_lock();
raw_spin_lock_irqsave(&kmemleak_lock, flags);
object = __lookup_object(ptr, alias, is_phys);
raw_spin_unlock_irqrestore(&kmemleak_lock, flags);
/* check whether the object is still available */
if (object && !get_object(object))
object = NULL;
rcu_read_unlock();
return object;
}
/* Look up and get an object which allocated with virtual address. */
static struct kmemleak_object *find_and_get_object(unsigned long ptr, int alias)
{
return __find_and_get_object(ptr, alias, false);
}
/*
* Remove an object from the object_tree_root (or object_phys_tree_root)
* and object_list. Must be called with the kmemleak_lock held _if_ kmemleak
* is still enabled.
*/
static void __remove_object(struct kmemleak_object *object)
{
rb_erase(&object->rb_node, object->flags & OBJECT_PHYS ?
&object_phys_tree_root :
&object_tree_root);
if (!(object->del_state & DELSTATE_NO_DELETE))
list_del_rcu(&object->object_list);
object->del_state |= DELSTATE_REMOVED;
}
/*
* Look up an object in the object search tree and remove it from both
* object_tree_root (or object_phys_tree_root) and object_list. The
* returned object's use_count should be at least 1, as initially set
* by create_object().
*/
static struct kmemleak_object *find_and_remove_object(unsigned long ptr, int alias,
bool is_phys)
{
unsigned long flags;
struct kmemleak_object *object;
raw_spin_lock_irqsave(&kmemleak_lock, flags);
object = __lookup_object(ptr, alias, is_phys);
if (object)
__remove_object(object);
raw_spin_unlock_irqrestore(&kmemleak_lock, flags);
return object;
}
static noinline depot_stack_handle_t set_track_prepare(void)
{
depot_stack_handle_t trace_handle;
unsigned long entries[MAX_TRACE];
unsigned int nr_entries;
/*
* Use object_cache to determine whether kmemleak_init() has
* been invoked. stack_depot_early_init() is called before
* kmemleak_init() in mm_core_init().
*/
if (!object_cache)
return 0;
nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 3);
trace_handle = stack_depot_save(entries, nr_entries, GFP_NOWAIT);
return trace_handle;
}
/*
* Create the metadata (struct kmemleak_object) corresponding to an allocated
* memory block and add it to the object_list and object_tree_root (or
* object_phys_tree_root).
*/
static void __create_object(unsigned long ptr, size_t size,
int min_count, gfp_t gfp, bool is_phys)
{
unsigned long flags;
struct kmemleak_object *object, *parent;
struct rb_node **link, *rb_parent;
unsigned long untagged_ptr;
unsigned long untagged_objp;
object = mem_pool_alloc(gfp);
if (!object) {
pr_warn("Cannot allocate a kmemleak_object structure\n");
kmemleak_disable();
return;
}
INIT_LIST_HEAD(&object->object_list);
INIT_LIST_HEAD(&object->gray_list);
INIT_HLIST_HEAD(&object->area_list);
raw_spin_lock_init(&object->lock);
atomic_set(&object->use_count, 1);
object->flags = OBJECT_ALLOCATED | (is_phys ? OBJECT_PHYS : 0);
object->pointer = ptr;
object->size = kfence_ksize((void *)ptr) ?: size;
object->excess_ref = 0;
object->min_count = min_count;
object->count = 0; /* white color initially */
object->jiffies = jiffies;
object->checksum = 0;
object->del_state = 0;
/* task information */
if (in_hardirq()) {
object->pid = 0;
strncpy(object->comm, "hardirq", sizeof(object->comm));
} else if (in_serving_softirq()) {
object->pid = 0;
strncpy(object->comm, "softirq", sizeof(object->comm));
} else {
object->pid = current->pid;
/*
* There is a small chance of a race with set_task_comm(),
* however using get_task_comm() here may cause locking
* dependency issues with current->alloc_lock. In the worst
* case, the command line is not correct.
*/
strncpy(object->comm, current->comm, sizeof(object->comm));
}
/* kernel backtrace */
object->trace_handle = set_track_prepare();
raw_spin_lock_irqsave(&kmemleak_lock, flags);
untagged_ptr = (unsigned long)kasan_reset_tag((void *)ptr);
/*
* Only update min_addr and max_addr with object
* storing virtual address.
*/
if (!is_phys) {
min_addr = min(min_addr, untagged_ptr);
max_addr = max(max_addr, untagged_ptr + size);
}
link = is_phys ? &object_phys_tree_root.rb_node :
&object_tree_root.rb_node;
rb_parent = NULL;
while (*link) {
rb_parent = *link;
parent = rb_entry(rb_parent, struct kmemleak_object, rb_node);
untagged_objp = (unsigned long)kasan_reset_tag((void *)parent->pointer);
if (untagged_ptr + size <= untagged_objp)
link = &parent->rb_node.rb_left;
else if (untagged_objp + parent->size <= untagged_ptr)
link = &parent->rb_node.rb_right;
else {
kmemleak_stop("Cannot insert 0x%lx into the object search tree (overlaps existing)\n",
ptr);
/*
* No need for parent->lock here since "parent" cannot
* be freed while the kmemleak_lock is held.
*/
dump_object_info(parent);
kmem_cache_free(object_cache, object);
goto out;
}
}
rb_link_node(&object->rb_node, rb_parent, link);
rb_insert_color(&object->rb_node, is_phys ? &object_phys_tree_root :
&object_tree_root);
list_add_tail_rcu(&object->object_list, &object_list);
out:
raw_spin_unlock_irqrestore(&kmemleak_lock, flags);
}
/* Create kmemleak object which allocated with virtual address. */
static void create_object(unsigned long ptr, size_t size,
int min_count, gfp_t gfp)
{
__create_object(ptr, size, min_count, gfp, false);
}
/* Create kmemleak object which allocated with physical address. */
static void create_object_phys(unsigned long ptr, size_t size,
int min_count, gfp_t gfp)
{
__create_object(ptr, size, min_count, gfp, true);
}
/*
* Mark the object as not allocated and schedule RCU freeing via put_object().
*/
static void __delete_object(struct kmemleak_object *object)
{
unsigned long flags;
WARN_ON(!(object->flags & OBJECT_ALLOCATED));
WARN_ON(atomic_read(&object->use_count) < 1);
/*
* Locking here also ensures that the corresponding memory block
* cannot be freed when it is being scanned.
*/
raw_spin_lock_irqsave(&object->lock, flags);
object->flags &= ~OBJECT_ALLOCATED;
raw_spin_unlock_irqrestore(&object->lock, flags);
put_object(object);
}
/*
* Look up the metadata (struct kmemleak_object) corresponding to ptr and
* delete it.
*/
static void delete_object_full(unsigned long ptr)
{
struct kmemleak_object *object;
object = find_and_remove_object(ptr, 0, false);
if (!object) {
#ifdef DEBUG
kmemleak_warn("Freeing unknown object at 0x%08lx\n",
ptr);
#endif
return;
}
__delete_object(object);
}
/*
* Look up the metadata (struct kmemleak_object) corresponding to ptr and
* delete it. If the memory block is partially freed, the function may create
* additional metadata for the remaining parts of the block.
*/
static void delete_object_part(unsigned long ptr, size_t size, bool is_phys)
{
struct kmemleak_object *object;
unsigned long start, end;
object = find_and_remove_object(ptr, 1, is_phys);
if (!object) {
#ifdef DEBUG
kmemleak_warn("Partially freeing unknown object at 0x%08lx (size %zu)\n",
ptr, size);
#endif
return;
}
/*
* Create one or two objects that may result from the memory block
* split. Note that partial freeing is only done by free_bootmem() and
* this happens before kmemleak_init() is called.
*/
start = object->pointer;
end = object->pointer + object->size;
if (ptr > start)
__create_object(start, ptr - start, object->min_count,
GFP_KERNEL, is_phys);
if (ptr + size < end)
__create_object(ptr + size, end - ptr - size, object->min_count,
GFP_KERNEL, is_phys);
__delete_object(object);
}
static void __paint_it(struct kmemleak_object *object, int color)
{
object->min_count = color;
if (color == KMEMLEAK_BLACK)
object->flags |= OBJECT_NO_SCAN;
}
static void paint_it(struct kmemleak_object *object, int color)
{
unsigned long flags;
raw_spin_lock_irqsave(&object->lock, flags);
__paint_it(object, color);
raw_spin_unlock_irqrestore(&object->lock, flags);
}
static void paint_ptr(unsigned long ptr, int color, bool is_phys)
{
struct kmemleak_object *object;
object = __find_and_get_object(ptr, 0, is_phys);
if (!object) {
kmemleak_warn("Trying to color unknown object at 0x%08lx as %s\n",
ptr,
(color == KMEMLEAK_GREY) ? "Grey" :
(color == KMEMLEAK_BLACK) ? "Black" : "Unknown");
return;
}
paint_it(object, color);
put_object(object);
}
/*
* Mark an object permanently as gray-colored so that it can no longer be
* reported as a leak. This is used in general to mark a false positive.
*/
static void make_gray_object(unsigned long ptr)
{
paint_ptr(ptr, KMEMLEAK_GREY, false);
}
/*
* Mark the object as black-colored so that it is ignored from scans and
* reporting.
*/
static void make_black_object(unsigned long ptr, bool is_phys)
{
paint_ptr(ptr, KMEMLEAK_BLACK, is_phys);
}
/*
* Add a scanning area to the object. If at least one such area is added,
* kmemleak will only scan these ranges rather than the whole memory block.
*/
static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp)
{
unsigned long flags;
struct kmemleak_object *object;
struct kmemleak_scan_area *area = NULL;
unsigned long untagged_ptr;
unsigned long untagged_objp;
object = find_and_get_object(ptr, 1);
if (!object) {
kmemleak_warn("Adding scan area to unknown object at 0x%08lx\n",
ptr);
return;
}
untagged_ptr = (unsigned long)kasan_reset_tag((void *)ptr);
untagged_objp = (unsigned long)kasan_reset_tag((void *)object->pointer);
if (scan_area_cache)
area = kmem_cache_alloc(scan_area_cache, gfp_kmemleak_mask(gfp));
raw_spin_lock_irqsave(&object->lock, flags);
if (!area) {
pr_warn_once("Cannot allocate a scan area, scanning the full object\n");
/* mark the object for full scan to avoid false positives */
object->flags |= OBJECT_FULL_SCAN;
goto out_unlock;
}
if (size == SIZE_MAX) {
size = untagged_objp + object->size - untagged_ptr;
} else if (untagged_ptr + size > untagged_objp + object->size) {
kmemleak_warn("Scan area larger than object 0x%08lx\n", ptr);
dump_object_info(object);
kmem_cache_free(scan_area_cache, area);
goto out_unlock;
}
INIT_HLIST_NODE(&area->node);
area->start = ptr;
area->size = size;
hlist_add_head(&area->node, &object->area_list);
out_unlock:
raw_spin_unlock_irqrestore(&object->lock, flags);
put_object(object);
}
/*
* Any surplus references (object already gray) to 'ptr' are passed to
* 'excess_ref'. This is used in the vmalloc() case where a pointer to
* vm_struct may be used as an alternative reference to the vmalloc'ed object
* (see free_thread_stack()).
*/
static void object_set_excess_ref(unsigned long ptr, unsigned long excess_ref)
{
unsigned long flags;
struct kmemleak_object *object;
object = find_and_get_object(ptr, 0);
if (!object) {
kmemleak_warn("Setting excess_ref on unknown object at 0x%08lx\n",
ptr);
return;
}
raw_spin_lock_irqsave(&object->lock, flags);
object->excess_ref = excess_ref;
raw_spin_unlock_irqrestore(&object->lock, flags);
put_object(object);
}
/*
* Set the OBJECT_NO_SCAN flag for the object corresponding to the give
* pointer. Such object will not be scanned by kmemleak but references to it
* are searched.
*/
static void object_no_scan(unsigned long ptr)
{
unsigned long flags;
struct kmemleak_object *object;
object = find_and_get_object(ptr, 0);
if (!object) {
kmemleak_warn("Not scanning unknown object at 0x%08lx\n", ptr);
return;
}
raw_spin_lock_irqsave(&object->lock, flags);
object->flags |= OBJECT_NO_SCAN;
raw_spin_unlock_irqrestore(&object->lock, flags);
put_object(object);
}
/**
* kmemleak_alloc - register a newly allocated object
* @ptr: pointer to beginning of the object
* @size: size of the object
* @min_count: minimum number of references to this object. If during memory
* scanning a number of references less than @min_count is found,
* the object is reported as a memory leak. If @min_count is 0,
* the object is never reported as a leak. If @min_count is -1,
* the object is ignored (not scanned and not reported as a leak)
* @gfp: kmalloc() flags used for kmemleak internal memory allocations
*
* This function is called from the kernel allocators when a new object
* (memory block) is allocated (kmem_cache_alloc, kmalloc etc.).
*/
void __ref kmemleak_alloc(const void *ptr, size_t size, int min_count,
gfp_t gfp)
{
pr_debug("%s(0x%p, %zu, %d)\n", __func__, ptr, size, min_count);
if (kmemleak_enabled && ptr && !IS_ERR(ptr))
create_object((unsigned long)ptr, size, min_count, gfp);
}
EXPORT_SYMBOL_GPL(kmemleak_alloc);
/**
* kmemleak_alloc_percpu - register a newly allocated __percpu object
* @ptr: __percpu pointer to beginning of the object
* @size: size of the object
* @gfp: flags used for kmemleak internal memory allocations
*
* This function is called from the kernel percpu allocator when a new object
* (memory block) is allocated (alloc_percpu).
*/
void __ref kmemleak_alloc_percpu(const void __percpu *ptr, size_t size,
gfp_t gfp)
{
unsigned int cpu;
pr_debug("%s(0x%p, %zu)\n", __func__, ptr, size);
/*
* Percpu allocations are only scanned and not reported as leaks
* (min_count is set to 0).
*/
if (kmemleak_enabled && ptr && !IS_ERR(ptr))
for_each_possible_cpu(cpu)
create_object((unsigned long)per_cpu_ptr(ptr, cpu),
size, 0, gfp);
}
EXPORT_SYMBOL_GPL(kmemleak_alloc_percpu);
/**
* kmemleak_vmalloc - register a newly vmalloc'ed object
* @area: pointer to vm_struct
* @size: size of the object
* @gfp: __vmalloc() flags used for kmemleak internal memory allocations
*
* This function is called from the vmalloc() kernel allocator when a new
* object (memory block) is allocated.
*/
void __ref kmemleak_vmalloc(const struct vm_struct *area, size_t size, gfp_t gfp)
{
pr_debug("%s(0x%p, %zu)\n", __func__, area, size);
/*
* A min_count = 2 is needed because vm_struct contains a reference to
* the virtual address of the vmalloc'ed block.
*/
if (kmemleak_enabled) {
create_object((unsigned long)area->addr, size, 2, gfp);
object_set_excess_ref((unsigned long)area,
(unsigned long)area->addr);
}
}
EXPORT_SYMBOL_GPL(kmemleak_vmalloc);
/**
* kmemleak_free - unregister a previously registered object
* @ptr: pointer to beginning of the object
*
* This function is called from the kernel allocators when an object (memory
* block) is freed (kmem_cache_free, kfree, vfree etc.).
*/
void __ref kmemleak_free(const void *ptr)
{
pr_debug("%s(0x%p)\n", __func__, ptr);
if (kmemleak_free_enabled && ptr && !IS_ERR(ptr))
delete_object_full((unsigned long)ptr);
}
EXPORT_SYMBOL_GPL(kmemleak_free);
/**
* kmemleak_free_part - partially unregister a previously registered object
* @ptr: pointer to the beginning or inside the object. This also
* represents the start of the range to be freed
* @size: size to be unregistered
*
* This function is called when only a part of a memory block is freed
* (usually from the bootmem allocator).
*/
void __ref kmemleak_free_part(const void *ptr, size_t size)
{
pr_debug("%s(0x%p)\n", __func__, ptr);
if (kmemleak_enabled && ptr && !IS_ERR(ptr))
delete_object_part((unsigned long)ptr, size, false);
}
EXPORT_SYMBOL_GPL(kmemleak_free_part);
/**
* kmemleak_free_percpu - unregister a previously registered __percpu object
* @ptr: __percpu pointer to beginning of the object
*
* This function is called from the kernel percpu allocator when an object
* (memory block) is freed (free_percpu).
*/
void __ref kmemleak_free_percpu(const void __percpu *ptr)
{
unsigned int cpu;
pr_debug("%s(0x%p)\n", __func__, ptr);
if (kmemleak_free_enabled && ptr && !IS_ERR(ptr))
for_each_possible_cpu(cpu)
delete_object_full((unsigned long)per_cpu_ptr(ptr,
cpu));
}
EXPORT_SYMBOL_GPL(kmemleak_free_percpu);
/**
* kmemleak_update_trace - update object allocation stack trace
* @ptr: pointer to beginning of the object
*
* Override the object allocation stack trace for cases where the actual
* allocation place is not always useful.
*/
void __ref kmemleak_update_trace(const void *ptr)
{
struct kmemleak_object *object;
unsigned long flags;
pr_debug("%s(0x%p)\n", __func__, ptr);
if (!kmemleak_enabled || IS_ERR_OR_NULL(ptr))
return;
object = find_and_get_object((unsigned long)ptr, 1);
if (!object) {
#ifdef DEBUG
kmemleak_warn("Updating stack trace for unknown object at %p\n",
ptr);
#endif
return;
}
raw_spin_lock_irqsave(&object->lock, flags);
object->trace_handle = set_track_prepare();
raw_spin_unlock_irqrestore(&object->lock, flags);
put_object(object);
}
EXPORT_SYMBOL(kmemleak_update_trace);
/**
* kmemleak_not_leak - mark an allocated object as false positive
* @ptr: pointer to beginning of the object
*
* Calling this function on an object will cause the memory block to no longer
* be reported as leak and always be scanned.
*/
void __ref kmemleak_not_leak(const void *ptr)
{
pr_debug("%s(0x%p)\n", __func__, ptr);
if (kmemleak_enabled && ptr && !IS_ERR(ptr))
make_gray_object((unsigned long)ptr);
}
EXPORT_SYMBOL(kmemleak_not_leak);
/**
* kmemleak_ignore - ignore an allocated object
* @ptr: pointer to beginning of the object
*
* Calling this function on an object will cause the memory block to be
* ignored (not scanned and not reported as a leak). This is usually done when
* it is known that the corresponding block is not a leak and does not contain
* any references to other allocated memory blocks.
*/
void __ref kmemleak_ignore(const void *ptr)
{
pr_debug("%s(0x%p)\n", __func__, ptr);
if (kmemleak_enabled && ptr && !IS_ERR(ptr))
make_black_object((unsigned long)ptr, false);
}
EXPORT_SYMBOL(kmemleak_ignore);
/**
* kmemleak_scan_area - limit the range to be scanned in an allocated object
* @ptr: pointer to beginning or inside the object. This also
* represents the start of the scan area
* @size: size of the scan area
* @gfp: kmalloc() flags used for kmemleak internal memory allocations
*
* This function is used when it is known that only certain parts of an object
* contain references to other objects. Kmemleak will only scan these areas
* reducing the number false negatives.
*/
void __ref kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp)
{
pr_debug("%s(0x%p)\n", __func__, ptr);
if (kmemleak_enabled && ptr && size && !IS_ERR(ptr))
add_scan_area((unsigned long)ptr, size, gfp);
}
EXPORT_SYMBOL(kmemleak_scan_area);
/**
* kmemleak_no_scan - do not scan an allocated object
* @ptr: pointer to beginning of the object
*
* This function notifies kmemleak not to scan the given memory block. Useful
* in situations where it is known that the given object does not contain any
* references to other objects. Kmemleak will not scan such objects reducing
* the number of false negatives.
*/
void __ref kmemleak_no_scan(const void *ptr)
{
pr_debug("%s(0x%p)\n", __func__, ptr);
if (kmemleak_enabled && ptr && !IS_ERR(ptr))
object_no_scan((unsigned long)ptr);
}
EXPORT_SYMBOL(kmemleak_no_scan);
/**
* kmemleak_alloc_phys - similar to kmemleak_alloc but taking a physical
* address argument
* @phys: physical address of the object
* @size: size of the object
* @gfp: kmalloc() flags used for kmemleak internal memory allocations
*/
void __ref kmemleak_alloc_phys(phys_addr_t phys, size_t size, gfp_t gfp)
{
pr_debug("%s(0x%pa, %zu)\n", __func__, &phys, size);
if (kmemleak_enabled)
/*
* Create object with OBJECT_PHYS flag and
* assume min_count 0.
*/
create_object_phys((unsigned long)phys, size, 0, gfp);
}
EXPORT_SYMBOL(kmemleak_alloc_phys);
/**
* kmemleak_free_part_phys - similar to kmemleak_free_part but taking a
* physical address argument
* @phys: physical address if the beginning or inside an object. This
* also represents the start of the range to be freed
* @size: size to be unregistered
*/
void __ref kmemleak_free_part_phys(phys_addr_t phys, size_t size)
{
pr_debug("%s(0x%pa)\n", __func__, &phys);
if (kmemleak_enabled)
delete_object_part((unsigned long)phys, size, true);
}
EXPORT_SYMBOL(kmemleak_free_part_phys);
/**
* kmemleak_ignore_phys - similar to kmemleak_ignore but taking a physical
* address argument
* @phys: physical address of the object
*/
void __ref kmemleak_ignore_phys(phys_addr_t phys)
{
pr_debug("%s(0x%pa)\n", __func__, &phys);
if (kmemleak_enabled)
make_black_object((unsigned long)phys, true);
}
EXPORT_SYMBOL(kmemleak_ignore_phys);
/*
* Update an object's checksum and return true if it was modified.
*/
static bool update_checksum(struct kmemleak_object *object)
{
u32 old_csum = object->checksum;
if (WARN_ON_ONCE(object->flags & OBJECT_PHYS))
return false;
kasan_disable_current();
kcsan_disable_current();
object->checksum = crc32(0, kasan_reset_tag((void *)object->pointer), object->size);
kasan_enable_current();
kcsan_enable_current();
return object->checksum != old_csum;
}
/*
* Update an object's references. object->lock must be held by the caller.
*/
static void update_refs(struct kmemleak_object *object)
{
if (!color_white(object)) {
/* non-orphan, ignored or new */
return;
}
/*
* Increase the object's reference count (number of pointers to the
* memory block). If this count reaches the required minimum, the
* object's color will become gray and it will be added to the
* gray_list.
*/
object->count++;
if (color_gray(object)) {
/* put_object() called when removing from gray_list */
WARN_ON(!get_object(object));
list_add_tail(&object->gray_list, &gray_list);
}
}
/*
* Memory scanning is a long process and it needs to be interruptible. This
* function checks whether such interrupt condition occurred.
*/
static int scan_should_stop(void)
{
if (!kmemleak_enabled)
return 1;
/*
* This function may be called from either process or kthread context,
* hence the need to check for both stop conditions.
*/
if (current->mm)
return signal_pending(current);
else
return kthread_should_stop();
return 0;
}
/*
* Scan a memory block (exclusive range) for valid pointers and add those
* found to the gray list.
*/
static void scan_block(void *_start, void *_end,
struct kmemleak_object *scanned)
{
unsigned long *ptr;
unsigned long *start = PTR_ALIGN(_start, BYTES_PER_POINTER);
unsigned long *end = _end - (BYTES_PER_POINTER - 1);
unsigned long flags;
unsigned long untagged_ptr;
raw_spin_lock_irqsave(&kmemleak_lock, flags);
for (ptr = start; ptr < end; ptr++) {
struct kmemleak_object *object;
unsigned long pointer;
unsigned long excess_ref;
if (scan_should_stop())
break;
kasan_disable_current();
pointer = *(unsigned long *)kasan_reset_tag((void *)ptr);
kasan_enable_current();
untagged_ptr = (unsigned long)kasan_reset_tag((void *)pointer);
if (untagged_ptr < min_addr || untagged_ptr >= max_addr)
continue;
/*
* No need for get_object() here since we hold kmemleak_lock.
* object->use_count cannot be dropped to 0 while the object
* is still present in object_tree_root and object_list
* (with updates protected by kmemleak_lock).
*/
object = lookup_object(pointer, 1);
if (!object)
continue;
if (object == scanned)
/* self referenced, ignore */
continue;
/*
* Avoid the lockdep recursive warning on object->lock being
* previously acquired in scan_object(). These locks are
* enclosed by scan_mutex.
*/
raw_spin_lock_nested(&object->lock, SINGLE_DEPTH_NESTING);
/* only pass surplus references (object already gray) */
if (color_gray(object)) {
excess_ref = object->excess_ref;
/* no need for update_refs() if object already gray */
} else {
excess_ref = 0;
update_refs(object);
}
raw_spin_unlock(&object->lock);
if (excess_ref) {
object = lookup_object(excess_ref, 0);
if (!object)
continue;
if (object == scanned)
/* circular reference, ignore */
continue;
raw_spin_lock_nested(&object->lock, SINGLE_DEPTH_NESTING);
update_refs(object);
raw_spin_unlock(&object->lock);
}
}
raw_spin_unlock_irqrestore(&kmemleak_lock, flags);
}
/*
* Scan a large memory block in MAX_SCAN_SIZE chunks to reduce the latency.
*/
#ifdef CONFIG_SMP
static void scan_large_block(void *start, void *end)
{
void *next;
while (start < end) {
next = min(start + MAX_SCAN_SIZE, end);
scan_block(start, next, NULL);
start = next;
cond_resched();
}
}
#endif
/*
* Scan a memory block corresponding to a kmemleak_object. A condition is
* that object->use_count >= 1.
*/
static void scan_object(struct kmemleak_object *object)
{
struct kmemleak_scan_area *area;
unsigned long flags;
void *obj_ptr;
/*
* Once the object->lock is acquired, the corresponding memory block
* cannot be freed (the same lock is acquired in delete_object).
*/
raw_spin_lock_irqsave(&object->lock, flags);
if (object->flags & OBJECT_NO_SCAN)
goto out;
if (!(object->flags & OBJECT_ALLOCATED))
/* already freed object */
goto out;
obj_ptr = object->flags & OBJECT_PHYS ?
__va((phys_addr_t)object->pointer) :
(void *)object->pointer;
if (hlist_empty(&object->area_list) ||
object->flags & OBJECT_FULL_SCAN) {
void *start = obj_ptr;
void *end = obj_ptr + object->size;
void *next;
do {
next = min(start + MAX_SCAN_SIZE, end);
scan_block(start, next, object);
start = next;
if (start >= end)
break;
raw_spin_unlock_irqrestore(&object->lock, flags);
cond_resched();
raw_spin_lock_irqsave(&object->lock, flags);
} while (object->flags & OBJECT_ALLOCATED);
} else
hlist_for_each_entry(area, &object->area_list, node)
scan_block((void *)area->start,
(void *)(area->start + area->size),
object);
out:
raw_spin_unlock_irqrestore(&object->lock, flags);
}
/*
* Scan the objects already referenced (gray objects). More objects will be
* referenced and, if there are no memory leaks, all the objects are scanned.
*/
static void scan_gray_list(void)
{
struct kmemleak_object *object, *tmp;
/*
* The list traversal is safe for both tail additions and removals
* from inside the loop. The kmemleak objects cannot be freed from
* outside the loop because their use_count was incremented.
*/
object = list_entry(gray_list.next, typeof(*object), gray_list);
while (&object->gray_list != &gray_list) {
cond_resched();
/* may add new objects to the list */
if (!scan_should_stop())
scan_object(object);
tmp = list_entry(object->gray_list.next, typeof(*object),
gray_list);
/* remove the object from the list and release it */
list_del(&object->gray_list);
put_object(object);
object = tmp;
}
WARN_ON(!list_empty(&gray_list));
}
/*
* Conditionally call resched() in an object iteration loop while making sure
* that the given object won't go away without RCU read lock by performing a
* get_object() if necessaary.
*/
static void kmemleak_cond_resched(struct kmemleak_object *object)
{
if (!get_object(object))
return; /* Try next object */
raw_spin_lock_irq(&kmemleak_lock);
if (object->del_state & DELSTATE_REMOVED)
goto unlock_put; /* Object removed */
object->del_state |= DELSTATE_NO_DELETE;
raw_spin_unlock_irq(&kmemleak_lock);
rcu_read_unlock();
cond_resched();
rcu_read_lock();
raw_spin_lock_irq(&kmemleak_lock);
if (object->del_state & DELSTATE_REMOVED)
list_del_rcu(&object->object_list);
object->del_state &= ~DELSTATE_NO_DELETE;
unlock_put:
raw_spin_unlock_irq(&kmemleak_lock);
put_object(object);
}
/*
* Scan data sections and all the referenced memory blocks allocated via the
* kernel's standard allocators. This function must be called with the
* scan_mutex held.
*/
static void kmemleak_scan(void)
{
struct kmemleak_object *object;
struct zone *zone;
int __maybe_unused i;
int new_leaks = 0;
jiffies_last_scan = jiffies;
/* prepare the kmemleak_object's */
rcu_read_lock();
list_for_each_entry_rcu(object, &object_list, object_list) {
raw_spin_lock_irq(&object->lock);
#ifdef DEBUG
/*
* With a few exceptions there should be a maximum of
* 1 reference to any object at this point.
*/
if (atomic_read(&object->use_count) > 1) {
pr_debug("object->use_count = %d\n",
atomic_read(&object->use_count));
dump_object_info(object);
}
#endif
/* ignore objects outside lowmem (paint them black) */
if ((object->flags & OBJECT_PHYS) &&
!(object->flags & OBJECT_NO_SCAN)) {
unsigned long phys = object->pointer;
if (PHYS_PFN(phys) < min_low_pfn ||
PHYS_PFN(phys + object->size) >= max_low_pfn)
__paint_it(object, KMEMLEAK_BLACK);
}
/* reset the reference count (whiten the object) */
object->count = 0;
if (color_gray(object) && get_object(object))
list_add_tail(&object->gray_list, &gray_list);
raw_spin_unlock_irq(&object->lock);
if (need_resched())
kmemleak_cond_resched(object);
}
rcu_read_unlock();
#ifdef CONFIG_SMP
/* per-cpu sections scanning */
for_each_possible_cpu(i)
scan_large_block(__per_cpu_start + per_cpu_offset(i),
__per_cpu_end + per_cpu_offset(i));
#endif
/*
* Struct page scanning for each node.
*/
get_online_mems();
for_each_populated_zone(zone) {
unsigned long start_pfn = zone->zone_start_pfn;
unsigned long end_pfn = zone_end_pfn(zone);
unsigned long pfn;
for (pfn = start_pfn; pfn < end_pfn; pfn++) {
struct page *page = pfn_to_online_page(pfn);
if (!(pfn & 63))
cond_resched();
if (!page)
continue;
/* only scan pages belonging to this zone */
if (page_zone(page) != zone)
continue;
/* only scan if page is in use */
if (page_count(page) == 0)
continue;
scan_block(page, page + 1, NULL);
}
}
put_online_mems();
/*
* Scanning the task stacks (may introduce false negatives).
*/
if (kmemleak_stack_scan) {
struct task_struct *p, *g;
rcu_read_lock();
for_each_process_thread(g, p) {
void *stack = try_get_task_stack(p);
if (stack) {
scan_block(stack, stack + THREAD_SIZE, NULL);
put_task_stack(p);
}
}
rcu_read_unlock();
}
/*
* Scan the objects already referenced from the sections scanned
* above.
*/
scan_gray_list();
/*
* Check for new or unreferenced objects modified since the previous
* scan and color them gray until the next scan.
*/
rcu_read_lock();
list_for_each_entry_rcu(object, &object_list, object_list) {
if (need_resched())
kmemleak_cond_resched(object);
/*
* This is racy but we can save the overhead of lock/unlock
* calls. The missed objects, if any, should be caught in
* the next scan.
*/
if (!color_white(object))
continue;
raw_spin_lock_irq(&object->lock);
if (color_white(object) && (object->flags & OBJECT_ALLOCATED)
&& update_checksum(object) && get_object(object)) {
/* color it gray temporarily */
object->count = object->min_count;
list_add_tail(&object->gray_list, &gray_list);
}
raw_spin_unlock_irq(&object->lock);
}
rcu_read_unlock();
/*
* Re-scan the gray list for modified unreferenced objects.
*/
scan_gray_list();
/*
* If scanning was stopped do not report any new unreferenced objects.
*/
if (scan_should_stop())
return;
/*
* Scanning result reporting.
*/
rcu_read_lock();
list_for_each_entry_rcu(object, &object_list, object_list) {
if (need_resched())
kmemleak_cond_resched(object);
/*
* This is racy but we can save the overhead of lock/unlock
* calls. The missed objects, if any, should be caught in
* the next scan.
*/
if (!color_white(object))
continue;
raw_spin_lock_irq(&object->lock);
if (unreferenced_object(object) &&
!(object->flags & OBJECT_REPORTED)) {
object->flags |= OBJECT_REPORTED;
if (kmemleak_verbose)
print_unreferenced(NULL, object);
new_leaks++;
}
raw_spin_unlock_irq(&object->lock);
}
rcu_read_unlock();
if (new_leaks) {
kmemleak_found_leaks = true;
pr_info("%d new suspected memory leaks (see /sys/kernel/debug/kmemleak)\n",
new_leaks);
}
}
/*
* Thread function performing automatic memory scanning. Unreferenced objects
* at the end of a memory scan are reported but only the first time.
*/
static int kmemleak_scan_thread(void *arg)
{
static int first_run = IS_ENABLED(CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN);
pr_info("Automatic memory scanning thread started\n");
set_user_nice(current, 10);
/*
* Wait before the first scan to allow the system to fully initialize.
*/
if (first_run) {
signed long timeout = msecs_to_jiffies(SECS_FIRST_SCAN * 1000);
first_run = 0;
while (timeout && !kthread_should_stop())
timeout = schedule_timeout_interruptible(timeout);
}
while (!kthread_should_stop()) {
signed long timeout = READ_ONCE(jiffies_scan_wait);
mutex_lock(&scan_mutex);
kmemleak_scan();
mutex_unlock(&scan_mutex);
/* wait before the next scan */
while (timeout && !kthread_should_stop())
timeout = schedule_timeout_interruptible(timeout);
}
pr_info("Automatic memory scanning thread ended\n");
return 0;
}
/*
* Start the automatic memory scanning thread. This function must be called
* with the scan_mutex held.
*/
static void start_scan_thread(void)
{
if (scan_thread)
return;
scan_thread = kthread_run(kmemleak_scan_thread, NULL, "kmemleak");
if (IS_ERR(scan_thread)) {
pr_warn("Failed to create the scan thread\n");
scan_thread = NULL;
}
}
/*
* Stop the automatic memory scanning thread.
*/
static void stop_scan_thread(void)
{
if (scan_thread) {
kthread_stop(scan_thread);
scan_thread = NULL;
}
}
/*
* Iterate over the object_list and return the first valid object at or after
* the required position with its use_count incremented. The function triggers
* a memory scanning when the pos argument points to the first position.
*/
static void *kmemleak_seq_start(struct seq_file *seq, loff_t *pos)
{
struct kmemleak_object *object;
loff_t n = *pos;
int err;
err = mutex_lock_interruptible(&scan_mutex);
if (err < 0)
return ERR_PTR(err);
rcu_read_lock();
list_for_each_entry_rcu(object, &object_list, object_list) {
if (n-- > 0)
continue;
if (get_object(object))
goto out;
}
object = NULL;
out:
return object;
}
/*
* Return the next object in the object_list. The function decrements the
* use_count of the previous object and increases that of the next one.
*/
static void *kmemleak_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct kmemleak_object *prev_obj = v;
struct kmemleak_object *next_obj = NULL;
struct kmemleak_object *obj = prev_obj;
++(*pos);
list_for_each_entry_continue_rcu(obj, &object_list, object_list) {
if (get_object(obj)) {
next_obj = obj;
break;
}
}
put_object(prev_obj);
return next_obj;
}
/*
* Decrement the use_count of the last object required, if any.
*/
static void kmemleak_seq_stop(struct seq_file *seq, void *v)
{
if (!IS_ERR(v)) {
/*
* kmemleak_seq_start may return ERR_PTR if the scan_mutex
* waiting was interrupted, so only release it if !IS_ERR.
*/
rcu_read_unlock();
mutex_unlock(&scan_mutex);
if (v)
put_object(v);
}
}
/*
* Print the information for an unreferenced object to the seq file.
*/
static int kmemleak_seq_show(struct seq_file *seq, void *v)
{
struct kmemleak_object *object = v;
unsigned long flags;
raw_spin_lock_irqsave(&object->lock, flags);
if ((object->flags & OBJECT_REPORTED) && unreferenced_object(object))
print_unreferenced(seq, object);
raw_spin_unlock_irqrestore(&object->lock, flags);
return 0;
}
static const struct seq_operations kmemleak_seq_ops = {
.start = kmemleak_seq_start,
.next = kmemleak_seq_next,
.stop = kmemleak_seq_stop,
.show = kmemleak_seq_show,
};
static int kmemleak_open(struct inode *inode, struct file *file)
{
return seq_open(file, &kmemleak_seq_ops);
}
static int dump_str_object_info(const char *str)
{
unsigned long flags;
struct kmemleak_object *object;
unsigned long addr;
if (kstrtoul(str, 0, &addr))
return -EINVAL;
object = find_and_get_object(addr, 0);
if (!object) {
pr_info("Unknown object at 0x%08lx\n", addr);
return -EINVAL;
}
raw_spin_lock_irqsave(&object->lock, flags);
dump_object_info(object);
raw_spin_unlock_irqrestore(&object->lock, flags);
put_object(object);
return 0;
}
/*
* We use grey instead of black to ensure we can do future scans on the same
* objects. If we did not do future scans these black objects could
* potentially contain references to newly allocated objects in the future and
* we'd end up with false positives.
*/
static void kmemleak_clear(void)
{
struct kmemleak_object *object;
rcu_read_lock();
list_for_each_entry_rcu(object, &object_list, object_list) {
raw_spin_lock_irq(&object->lock);
if ((object->flags & OBJECT_REPORTED) &&
unreferenced_object(object))
__paint_it(object, KMEMLEAK_GREY);
raw_spin_unlock_irq(&object->lock);
}
rcu_read_unlock();
kmemleak_found_leaks = false;
}
static void __kmemleak_do_cleanup(void);
/*
* File write operation to configure kmemleak at run-time. The following
* commands can be written to the /sys/kernel/debug/kmemleak file:
* off - disable kmemleak (irreversible)
* stack=on - enable the task stacks scanning
* stack=off - disable the tasks stacks scanning
* scan=on - start the automatic memory scanning thread
* scan=off - stop the automatic memory scanning thread
* scan=... - set the automatic memory scanning period in seconds (0 to
* disable it)
* scan - trigger a memory scan
* clear - mark all current reported unreferenced kmemleak objects as
* grey to ignore printing them, or free all kmemleak objects
* if kmemleak has been disabled.
* dump=... - dump information about the object found at the given address
*/
static ssize_t kmemleak_write(struct file *file, const char __user *user_buf,
size_t size, loff_t *ppos)
{
char buf[64];
int buf_size;
int ret;
buf_size = min(size, (sizeof(buf) - 1));
if (strncpy_from_user(buf, user_buf, buf_size) < 0)
return -EFAULT;
buf[buf_size] = 0;
ret = mutex_lock_interruptible(&scan_mutex);
if (ret < 0)
return ret;
if (strncmp(buf, "clear", 5) == 0) {
if (kmemleak_enabled)
kmemleak_clear();
else
__kmemleak_do_cleanup();
goto out;
}
if (!kmemleak_enabled) {
ret = -EPERM;
goto out;
}
if (strncmp(buf, "off", 3) == 0)
kmemleak_disable();
else if (strncmp(buf, "stack=on", 8) == 0)
kmemleak_stack_scan = 1;
else if (strncmp(buf, "stack=off", 9) == 0)
kmemleak_stack_scan = 0;
else if (strncmp(buf, "scan=on", 7) == 0)
start_scan_thread();
else if (strncmp(buf, "scan=off", 8) == 0)
stop_scan_thread();
else if (strncmp(buf, "scan=", 5) == 0) {
unsigned secs;
unsigned long msecs;
ret = kstrtouint(buf + 5, 0, &secs);
if (ret < 0)
goto out;
msecs = secs * MSEC_PER_SEC;
if (msecs > UINT_MAX)
msecs = UINT_MAX;
stop_scan_thread();
if (msecs) {
WRITE_ONCE(jiffies_scan_wait, msecs_to_jiffies(msecs));
start_scan_thread();
}
} else if (strncmp(buf, "scan", 4) == 0)
kmemleak_scan();
else if (strncmp(buf, "dump=", 5) == 0)
ret = dump_str_object_info(buf + 5);
else
ret = -EINVAL;
out:
mutex_unlock(&scan_mutex);
if (ret < 0)
return ret;
/* ignore the rest of the buffer, only one command at a time */
*ppos += size;
return size;
}
static const struct file_operations kmemleak_fops = {
.owner = THIS_MODULE,
.open = kmemleak_open,
.read = seq_read,
.write = kmemleak_write,
.llseek = seq_lseek,
.release = seq_release,
};
static void __kmemleak_do_cleanup(void)
{
struct kmemleak_object *object, *tmp;
/*
* Kmemleak has already been disabled, no need for RCU list traversal
* or kmemleak_lock held.
*/
list_for_each_entry_safe(object, tmp, &object_list, object_list) {
__remove_object(object);
__delete_object(object);
}
}
/*
* Stop the memory scanning thread and free the kmemleak internal objects if
* no previous scan thread (otherwise, kmemleak may still have some useful
* information on memory leaks).
*/
static void kmemleak_do_cleanup(struct work_struct *work)
{
stop_scan_thread();
mutex_lock(&scan_mutex);
/*
* Once it is made sure that kmemleak_scan has stopped, it is safe to no
* longer track object freeing. Ordering of the scan thread stopping and
* the memory accesses below is guaranteed by the kthread_stop()
* function.
*/
kmemleak_free_enabled = 0;
mutex_unlock(&scan_mutex);
if (!kmemleak_found_leaks)
__kmemleak_do_cleanup();
else
pr_info("Kmemleak disabled without freeing internal data. Reclaim the memory with \"echo clear > /sys/kernel/debug/kmemleak\".\n");
}
static DECLARE_WORK(cleanup_work, kmemleak_do_cleanup);
/*
* Disable kmemleak. No memory allocation/freeing will be traced once this
* function is called. Disabling kmemleak is an irreversible operation.
*/
static void kmemleak_disable(void)
{
/* atomically check whether it was already invoked */
if (cmpxchg(&kmemleak_error, 0, 1))
return;
/* stop any memory operation tracing */
kmemleak_enabled = 0;
/* check whether it is too early for a kernel thread */
if (kmemleak_late_initialized)
schedule_work(&cleanup_work);
else
kmemleak_free_enabled = 0;
pr_info("Kernel memory leak detector disabled\n");
}
/*
* Allow boot-time kmemleak disabling (enabled by default).
*/
static int __init kmemleak_boot_config(char *str)
{
if (!str)
return -EINVAL;
if (strcmp(str, "off") == 0)
kmemleak_disable();
else if (strcmp(str, "on") == 0) {
kmemleak_skip_disable = 1;
stack_depot_request_early_init();
}
else
return -EINVAL;
return 0;
}
early_param("kmemleak", kmemleak_boot_config);
/*
* Kmemleak initialization.
*/
void __init kmemleak_init(void)
{
#ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF
if (!kmemleak_skip_disable) {
kmemleak_disable();
return;
}
#endif
if (kmemleak_error)
return;
jiffies_min_age = msecs_to_jiffies(MSECS_MIN_AGE);
jiffies_scan_wait = msecs_to_jiffies(SECS_SCAN_WAIT * 1000);
object_cache = KMEM_CACHE(kmemleak_object, SLAB_NOLEAKTRACE);
scan_area_cache = KMEM_CACHE(kmemleak_scan_area, SLAB_NOLEAKTRACE);
/* register the data/bss sections */
create_object((unsigned long)_sdata, _edata - _sdata,
KMEMLEAK_GREY, GFP_ATOMIC);
create_object((unsigned long)__bss_start, __bss_stop - __bss_start,
KMEMLEAK_GREY, GFP_ATOMIC);
/* only register .data..ro_after_init if not within .data */
if (&__start_ro_after_init < &_sdata || &__end_ro_after_init > &_edata)
create_object((unsigned long)__start_ro_after_init,
__end_ro_after_init - __start_ro_after_init,
KMEMLEAK_GREY, GFP_ATOMIC);
}
/*
* Late initialization function.
*/
static int __init kmemleak_late_init(void)
{
kmemleak_late_initialized = 1;
debugfs_create_file("kmemleak", 0644, NULL, NULL, &kmemleak_fops);
if (kmemleak_error) {
/*
* Some error occurred and kmemleak was disabled. There is a
* small chance that kmemleak_disable() was called immediately
* after setting kmemleak_late_initialized and we may end up with
* two clean-up threads but serialized by scan_mutex.
*/
schedule_work(&cleanup_work);
return -ENOMEM;
}
if (IS_ENABLED(CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN)) {
mutex_lock(&scan_mutex);
start_scan_thread();
mutex_unlock(&scan_mutex);
}
pr_info("Kernel memory leak detector initialized (mem pool available: %d)\n",
mem_pool_free_count);
return 0;
}
late_initcall(kmemleak_late_init);
| linux-master | mm/kmemleak.c |
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Contiguous Memory Allocator
*
* Copyright (c) 2010-2011 by Samsung Electronics.
* Copyright IBM Corporation, 2013
* Copyright LG Electronics Inc., 2014
* Written by:
* Marek Szyprowski <[email protected]>
* Michal Nazarewicz <[email protected]>
* Aneesh Kumar K.V <[email protected]>
* Joonsoo Kim <[email protected]>
*/
#define pr_fmt(fmt) "cma: " fmt
#ifdef CONFIG_CMA_DEBUG
#ifndef DEBUG
# define DEBUG
#endif
#endif
#define CREATE_TRACE_POINTS
#include <linux/memblock.h>
#include <linux/err.h>
#include <linux/mm.h>
#include <linux/sizes.h>
#include <linux/slab.h>
#include <linux/log2.h>
#include <linux/cma.h>
#include <linux/highmem.h>
#include <linux/io.h>
#include <linux/kmemleak.h>
#include <trace/events/cma.h>
#include "internal.h"
#include "cma.h"
struct cma cma_areas[MAX_CMA_AREAS];
unsigned cma_area_count;
static DEFINE_MUTEX(cma_mutex);
phys_addr_t cma_get_base(const struct cma *cma)
{
return PFN_PHYS(cma->base_pfn);
}
unsigned long cma_get_size(const struct cma *cma)
{
return cma->count << PAGE_SHIFT;
}
const char *cma_get_name(const struct cma *cma)
{
return cma->name;
}
static unsigned long cma_bitmap_aligned_mask(const struct cma *cma,
unsigned int align_order)
{
if (align_order <= cma->order_per_bit)
return 0;
return (1UL << (align_order - cma->order_per_bit)) - 1;
}
/*
* Find the offset of the base PFN from the specified align_order.
* The value returned is represented in order_per_bits.
*/
static unsigned long cma_bitmap_aligned_offset(const struct cma *cma,
unsigned int align_order)
{
return (cma->base_pfn & ((1UL << align_order) - 1))
>> cma->order_per_bit;
}
static unsigned long cma_bitmap_pages_to_bits(const struct cma *cma,
unsigned long pages)
{
return ALIGN(pages, 1UL << cma->order_per_bit) >> cma->order_per_bit;
}
static void cma_clear_bitmap(struct cma *cma, unsigned long pfn,
unsigned long count)
{
unsigned long bitmap_no, bitmap_count;
unsigned long flags;
bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
bitmap_count = cma_bitmap_pages_to_bits(cma, count);
spin_lock_irqsave(&cma->lock, flags);
bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
spin_unlock_irqrestore(&cma->lock, flags);
}
static void __init cma_activate_area(struct cma *cma)
{
unsigned long base_pfn = cma->base_pfn, pfn;
struct zone *zone;
cma->bitmap = bitmap_zalloc(cma_bitmap_maxno(cma), GFP_KERNEL);
if (!cma->bitmap)
goto out_error;
/*
* alloc_contig_range() requires the pfn range specified to be in the
* same zone. Simplify by forcing the entire CMA resv range to be in the
* same zone.
*/
WARN_ON_ONCE(!pfn_valid(base_pfn));
zone = page_zone(pfn_to_page(base_pfn));
for (pfn = base_pfn + 1; pfn < base_pfn + cma->count; pfn++) {
WARN_ON_ONCE(!pfn_valid(pfn));
if (page_zone(pfn_to_page(pfn)) != zone)
goto not_in_zone;
}
for (pfn = base_pfn; pfn < base_pfn + cma->count;
pfn += pageblock_nr_pages)
init_cma_reserved_pageblock(pfn_to_page(pfn));
spin_lock_init(&cma->lock);
#ifdef CONFIG_CMA_DEBUGFS
INIT_HLIST_HEAD(&cma->mem_head);
spin_lock_init(&cma->mem_head_lock);
#endif
return;
not_in_zone:
bitmap_free(cma->bitmap);
out_error:
/* Expose all pages to the buddy, they are useless for CMA. */
if (!cma->reserve_pages_on_error) {
for (pfn = base_pfn; pfn < base_pfn + cma->count; pfn++)
free_reserved_page(pfn_to_page(pfn));
}
totalcma_pages -= cma->count;
cma->count = 0;
pr_err("CMA area %s could not be activated\n", cma->name);
return;
}
static int __init cma_init_reserved_areas(void)
{
int i;
for (i = 0; i < cma_area_count; i++)
cma_activate_area(&cma_areas[i]);
return 0;
}
core_initcall(cma_init_reserved_areas);
void __init cma_reserve_pages_on_error(struct cma *cma)
{
cma->reserve_pages_on_error = true;
}
/**
* cma_init_reserved_mem() - create custom contiguous area from reserved memory
* @base: Base address of the reserved area
* @size: Size of the reserved area (in bytes),
* @order_per_bit: Order of pages represented by one bit on bitmap.
* @name: The name of the area. If this parameter is NULL, the name of
* the area will be set to "cmaN", where N is a running counter of
* used areas.
* @res_cma: Pointer to store the created cma region.
*
* This function creates custom contiguous area from already reserved memory.
*/
int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
unsigned int order_per_bit,
const char *name,
struct cma **res_cma)
{
struct cma *cma;
/* Sanity checks */
if (cma_area_count == ARRAY_SIZE(cma_areas)) {
pr_err("Not enough slots for CMA reserved regions!\n");
return -ENOSPC;
}
if (!size || !memblock_is_region_reserved(base, size))
return -EINVAL;
/* alignment should be aligned with order_per_bit */
if (!IS_ALIGNED(CMA_MIN_ALIGNMENT_PAGES, 1 << order_per_bit))
return -EINVAL;
/* ensure minimal alignment required by mm core */
if (!IS_ALIGNED(base | size, CMA_MIN_ALIGNMENT_BYTES))
return -EINVAL;
/*
* Each reserved area must be initialised later, when more kernel
* subsystems (like slab allocator) are available.
*/
cma = &cma_areas[cma_area_count];
if (name)
snprintf(cma->name, CMA_MAX_NAME, name);
else
snprintf(cma->name, CMA_MAX_NAME, "cma%d\n", cma_area_count);
cma->base_pfn = PFN_DOWN(base);
cma->count = size >> PAGE_SHIFT;
cma->order_per_bit = order_per_bit;
*res_cma = cma;
cma_area_count++;
totalcma_pages += (size / PAGE_SIZE);
return 0;
}
/**
* cma_declare_contiguous_nid() - reserve custom contiguous area
* @base: Base address of the reserved area optional, use 0 for any
* @size: Size of the reserved area (in bytes),
* @limit: End address of the reserved memory (optional, 0 for any).
* @alignment: Alignment for the CMA area, should be power of 2 or zero
* @order_per_bit: Order of pages represented by one bit on bitmap.
* @fixed: hint about where to place the reserved area
* @name: The name of the area. See function cma_init_reserved_mem()
* @res_cma: Pointer to store the created cma region.
* @nid: nid of the free area to find, %NUMA_NO_NODE for any node
*
* This function reserves memory from early allocator. It should be
* called by arch specific code once the early allocator (memblock or bootmem)
* has been activated and all other subsystems have already allocated/reserved
* memory. This function allows to create custom reserved areas.
*
* If @fixed is true, reserve contiguous area at exactly @base. If false,
* reserve in range from @base to @limit.
*/
int __init cma_declare_contiguous_nid(phys_addr_t base,
phys_addr_t size, phys_addr_t limit,
phys_addr_t alignment, unsigned int order_per_bit,
bool fixed, const char *name, struct cma **res_cma,
int nid)
{
phys_addr_t memblock_end = memblock_end_of_DRAM();
phys_addr_t highmem_start;
int ret = 0;
/*
* We can't use __pa(high_memory) directly, since high_memory
* isn't a valid direct map VA, and DEBUG_VIRTUAL will (validly)
* complain. Find the boundary by adding one to the last valid
* address.
*/
highmem_start = __pa(high_memory - 1) + 1;
pr_debug("%s(size %pa, base %pa, limit %pa alignment %pa)\n",
__func__, &size, &base, &limit, &alignment);
if (cma_area_count == ARRAY_SIZE(cma_areas)) {
pr_err("Not enough slots for CMA reserved regions!\n");
return -ENOSPC;
}
if (!size)
return -EINVAL;
if (alignment && !is_power_of_2(alignment))
return -EINVAL;
if (!IS_ENABLED(CONFIG_NUMA))
nid = NUMA_NO_NODE;
/* Sanitise input arguments. */
alignment = max_t(phys_addr_t, alignment, CMA_MIN_ALIGNMENT_BYTES);
if (fixed && base & (alignment - 1)) {
ret = -EINVAL;
pr_err("Region at %pa must be aligned to %pa bytes\n",
&base, &alignment);
goto err;
}
base = ALIGN(base, alignment);
size = ALIGN(size, alignment);
limit &= ~(alignment - 1);
if (!base)
fixed = false;
/* size should be aligned with order_per_bit */
if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
return -EINVAL;
/*
* If allocating at a fixed base the request region must not cross the
* low/high memory boundary.
*/
if (fixed && base < highmem_start && base + size > highmem_start) {
ret = -EINVAL;
pr_err("Region at %pa defined on low/high memory boundary (%pa)\n",
&base, &highmem_start);
goto err;
}
/*
* If the limit is unspecified or above the memblock end, its effective
* value will be the memblock end. Set it explicitly to simplify further
* checks.
*/
if (limit == 0 || limit > memblock_end)
limit = memblock_end;
if (base + size > limit) {
ret = -EINVAL;
pr_err("Size (%pa) of region at %pa exceeds limit (%pa)\n",
&size, &base, &limit);
goto err;
}
/* Reserve memory */
if (fixed) {
if (memblock_is_region_reserved(base, size) ||
memblock_reserve(base, size) < 0) {
ret = -EBUSY;
goto err;
}
} else {
phys_addr_t addr = 0;
/*
* If there is enough memory, try a bottom-up allocation first.
* It will place the new cma area close to the start of the node
* and guarantee that the compaction is moving pages out of the
* cma area and not into it.
* Avoid using first 4GB to not interfere with constrained zones
* like DMA/DMA32.
*/
#ifdef CONFIG_PHYS_ADDR_T_64BIT
if (!memblock_bottom_up() && memblock_end >= SZ_4G + size) {
memblock_set_bottom_up(true);
addr = memblock_alloc_range_nid(size, alignment, SZ_4G,
limit, nid, true);
memblock_set_bottom_up(false);
}
#endif
/*
* All pages in the reserved area must come from the same zone.
* If the requested region crosses the low/high memory boundary,
* try allocating from high memory first and fall back to low
* memory in case of failure.
*/
if (!addr && base < highmem_start && limit > highmem_start) {
addr = memblock_alloc_range_nid(size, alignment,
highmem_start, limit, nid, true);
limit = highmem_start;
}
if (!addr) {
addr = memblock_alloc_range_nid(size, alignment, base,
limit, nid, true);
if (!addr) {
ret = -ENOMEM;
goto err;
}
}
/*
* kmemleak scans/reads tracked objects for pointers to other
* objects but this address isn't mapped and accessible
*/
kmemleak_ignore_phys(addr);
base = addr;
}
ret = cma_init_reserved_mem(base, size, order_per_bit, name, res_cma);
if (ret)
goto free_mem;
pr_info("Reserved %ld MiB at %pa on node %d\n", (unsigned long)size / SZ_1M,
&base, nid);
return 0;
free_mem:
memblock_phys_free(base, size);
err:
pr_err("Failed to reserve %ld MiB on node %d\n", (unsigned long)size / SZ_1M,
nid);
return ret;
}
#ifdef CONFIG_CMA_DEBUG
static void cma_debug_show_areas(struct cma *cma)
{
unsigned long next_zero_bit, next_set_bit, nr_zero;
unsigned long start = 0;
unsigned long nr_part, nr_total = 0;
unsigned long nbits = cma_bitmap_maxno(cma);
spin_lock_irq(&cma->lock);
pr_info("number of available pages: ");
for (;;) {
next_zero_bit = find_next_zero_bit(cma->bitmap, nbits, start);
if (next_zero_bit >= nbits)
break;
next_set_bit = find_next_bit(cma->bitmap, nbits, next_zero_bit);
nr_zero = next_set_bit - next_zero_bit;
nr_part = nr_zero << cma->order_per_bit;
pr_cont("%s%lu@%lu", nr_total ? "+" : "", nr_part,
next_zero_bit);
nr_total += nr_part;
start = next_zero_bit + nr_zero;
}
pr_cont("=> %lu free of %lu total pages\n", nr_total, cma->count);
spin_unlock_irq(&cma->lock);
}
#else
static inline void cma_debug_show_areas(struct cma *cma) { }
#endif
/**
* cma_alloc() - allocate pages from contiguous area
* @cma: Contiguous memory region for which the allocation is performed.
* @count: Requested number of pages.
* @align: Requested alignment of pages (in PAGE_SIZE order).
* @no_warn: Avoid printing message about failed allocation
*
* This function allocates part of contiguous memory on specific
* contiguous memory area.
*/
struct page *cma_alloc(struct cma *cma, unsigned long count,
unsigned int align, bool no_warn)
{
unsigned long mask, offset;
unsigned long pfn = -1;
unsigned long start = 0;
unsigned long bitmap_maxno, bitmap_no, bitmap_count;
unsigned long i;
struct page *page = NULL;
int ret = -ENOMEM;
if (!cma || !cma->count || !cma->bitmap)
goto out;
pr_debug("%s(cma %p, name: %s, count %lu, align %d)\n", __func__,
(void *)cma, cma->name, count, align);
if (!count)
goto out;
trace_cma_alloc_start(cma->name, count, align);
mask = cma_bitmap_aligned_mask(cma, align);
offset = cma_bitmap_aligned_offset(cma, align);
bitmap_maxno = cma_bitmap_maxno(cma);
bitmap_count = cma_bitmap_pages_to_bits(cma, count);
if (bitmap_count > bitmap_maxno)
goto out;
for (;;) {
spin_lock_irq(&cma->lock);
bitmap_no = bitmap_find_next_zero_area_off(cma->bitmap,
bitmap_maxno, start, bitmap_count, mask,
offset);
if (bitmap_no >= bitmap_maxno) {
spin_unlock_irq(&cma->lock);
break;
}
bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
/*
* It's safe to drop the lock here. We've marked this region for
* our exclusive use. If the migration fails we will take the
* lock again and unmark it.
*/
spin_unlock_irq(&cma->lock);
pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
mutex_lock(&cma_mutex);
ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA,
GFP_KERNEL | (no_warn ? __GFP_NOWARN : 0));
mutex_unlock(&cma_mutex);
if (ret == 0) {
page = pfn_to_page(pfn);
break;
}
cma_clear_bitmap(cma, pfn, count);
if (ret != -EBUSY)
break;
pr_debug("%s(): memory range at pfn 0x%lx %p is busy, retrying\n",
__func__, pfn, pfn_to_page(pfn));
trace_cma_alloc_busy_retry(cma->name, pfn, pfn_to_page(pfn),
count, align);
/* try again with a bit different memory target */
start = bitmap_no + mask + 1;
}
trace_cma_alloc_finish(cma->name, pfn, page, count, align, ret);
/*
* CMA can allocate multiple page blocks, which results in different
* blocks being marked with different tags. Reset the tags to ignore
* those page blocks.
*/
if (page) {
for (i = 0; i < count; i++)
page_kasan_tag_reset(page + i);
}
if (ret && !no_warn) {
pr_err_ratelimited("%s: %s: alloc failed, req-size: %lu pages, ret: %d\n",
__func__, cma->name, count, ret);
cma_debug_show_areas(cma);
}
pr_debug("%s(): returned %p\n", __func__, page);
out:
if (page) {
count_vm_event(CMA_ALLOC_SUCCESS);
cma_sysfs_account_success_pages(cma, count);
} else {
count_vm_event(CMA_ALLOC_FAIL);
if (cma)
cma_sysfs_account_fail_pages(cma, count);
}
return page;
}
bool cma_pages_valid(struct cma *cma, const struct page *pages,
unsigned long count)
{
unsigned long pfn;
if (!cma || !pages)
return false;
pfn = page_to_pfn(pages);
if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count) {
pr_debug("%s(page %p, count %lu)\n", __func__,
(void *)pages, count);
return false;
}
return true;
}
/**
* cma_release() - release allocated pages
* @cma: Contiguous memory region for which the allocation is performed.
* @pages: Allocated pages.
* @count: Number of allocated pages.
*
* This function releases memory allocated by cma_alloc().
* It returns false when provided pages do not belong to contiguous area and
* true otherwise.
*/
bool cma_release(struct cma *cma, const struct page *pages,
unsigned long count)
{
unsigned long pfn;
if (!cma_pages_valid(cma, pages, count))
return false;
pr_debug("%s(page %p, count %lu)\n", __func__, (void *)pages, count);
pfn = page_to_pfn(pages);
VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
free_contig_range(pfn, count);
cma_clear_bitmap(cma, pfn, count);
trace_cma_release(cma->name, pfn, pages, count);
return true;
}
int cma_for_each_area(int (*it)(struct cma *cma, void *data), void *data)
{
int i;
for (i = 0; i < cma_area_count; i++) {
int ret = it(&cma_areas[i], data);
if (ret)
return ret;
}
return 0;
}
| linux-master | mm/cma.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/mm.h>
#include <linux/mmzone.h>
#include <linux/memblock.h>
#include <linux/page_ext.h>
#include <linux/memory.h>
#include <linux/vmalloc.h>
#include <linux/kmemleak.h>
#include <linux/page_owner.h>
#include <linux/page_idle.h>
#include <linux/page_table_check.h>
#include <linux/rcupdate.h>
/*
* struct page extension
*
* This is the feature to manage memory for extended data per page.
*
* Until now, we must modify struct page itself to store extra data per page.
* This requires rebuilding the kernel and it is really time consuming process.
* And, sometimes, rebuild is impossible due to third party module dependency.
* At last, enlarging struct page could cause un-wanted system behaviour change.
*
* This feature is intended to overcome above mentioned problems. This feature
* allocates memory for extended data per page in certain place rather than
* the struct page itself. This memory can be accessed by the accessor
* functions provided by this code. During the boot process, it checks whether
* allocation of huge chunk of memory is needed or not. If not, it avoids
* allocating memory at all. With this advantage, we can include this feature
* into the kernel in default and can avoid rebuild and solve related problems.
*
* To help these things to work well, there are two callbacks for clients. One
* is the need callback which is mandatory if user wants to avoid useless
* memory allocation at boot-time. The other is optional, init callback, which
* is used to do proper initialization after memory is allocated.
*
* The need callback is used to decide whether extended memory allocation is
* needed or not. Sometimes users want to deactivate some features in this
* boot and extra memory would be unnecessary. In this case, to avoid
* allocating huge chunk of memory, each clients represent their need of
* extra memory through the need callback. If one of the need callbacks
* returns true, it means that someone needs extra memory so that
* page extension core should allocates memory for page extension. If
* none of need callbacks return true, memory isn't needed at all in this boot
* and page extension core can skip to allocate memory. As result,
* none of memory is wasted.
*
* When need callback returns true, page_ext checks if there is a request for
* extra memory through size in struct page_ext_operations. If it is non-zero,
* extra space is allocated for each page_ext entry and offset is returned to
* user through offset in struct page_ext_operations.
*
* The init callback is used to do proper initialization after page extension
* is completely initialized. In sparse memory system, extra memory is
* allocated some time later than memmap is allocated. In other words, lifetime
* of memory for page extension isn't same with memmap for struct page.
* Therefore, clients can't store extra data until page extension is
* initialized, even if pages are allocated and used freely. This could
* cause inadequate state of extra data per page, so, to prevent it, client
* can utilize this callback to initialize the state of it correctly.
*/
#ifdef CONFIG_SPARSEMEM
#define PAGE_EXT_INVALID (0x1)
#endif
#if defined(CONFIG_PAGE_IDLE_FLAG) && !defined(CONFIG_64BIT)
static bool need_page_idle(void)
{
return true;
}
static struct page_ext_operations page_idle_ops __initdata = {
.need = need_page_idle,
.need_shared_flags = true,
};
#endif
static struct page_ext_operations *page_ext_ops[] __initdata = {
#ifdef CONFIG_PAGE_OWNER
&page_owner_ops,
#endif
#if defined(CONFIG_PAGE_IDLE_FLAG) && !defined(CONFIG_64BIT)
&page_idle_ops,
#endif
#ifdef CONFIG_PAGE_TABLE_CHECK
&page_table_check_ops,
#endif
};
unsigned long page_ext_size;
static unsigned long total_usage;
bool early_page_ext __meminitdata;
static int __init setup_early_page_ext(char *str)
{
early_page_ext = true;
return 0;
}
early_param("early_page_ext", setup_early_page_ext);
static bool __init invoke_need_callbacks(void)
{
int i;
int entries = ARRAY_SIZE(page_ext_ops);
bool need = false;
for (i = 0; i < entries; i++) {
if (page_ext_ops[i]->need()) {
if (page_ext_ops[i]->need_shared_flags) {
page_ext_size = sizeof(struct page_ext);
break;
}
}
}
for (i = 0; i < entries; i++) {
if (page_ext_ops[i]->need()) {
page_ext_ops[i]->offset = page_ext_size;
page_ext_size += page_ext_ops[i]->size;
need = true;
}
}
return need;
}
static void __init invoke_init_callbacks(void)
{
int i;
int entries = ARRAY_SIZE(page_ext_ops);
for (i = 0; i < entries; i++) {
if (page_ext_ops[i]->init)
page_ext_ops[i]->init();
}
}
static inline struct page_ext *get_entry(void *base, unsigned long index)
{
return base + page_ext_size * index;
}
#ifndef CONFIG_SPARSEMEM
void __init page_ext_init_flatmem_late(void)
{
invoke_init_callbacks();
}
void __meminit pgdat_page_ext_init(struct pglist_data *pgdat)
{
pgdat->node_page_ext = NULL;
}
static struct page_ext *lookup_page_ext(const struct page *page)
{
unsigned long pfn = page_to_pfn(page);
unsigned long index;
struct page_ext *base;
WARN_ON_ONCE(!rcu_read_lock_held());
base = NODE_DATA(page_to_nid(page))->node_page_ext;
/*
* The sanity checks the page allocator does upon freeing a
* page can reach here before the page_ext arrays are
* allocated when feeding a range of pages to the allocator
* for the first time during bootup or memory hotplug.
*/
if (unlikely(!base))
return NULL;
index = pfn - round_down(node_start_pfn(page_to_nid(page)),
MAX_ORDER_NR_PAGES);
return get_entry(base, index);
}
static int __init alloc_node_page_ext(int nid)
{
struct page_ext *base;
unsigned long table_size;
unsigned long nr_pages;
nr_pages = NODE_DATA(nid)->node_spanned_pages;
if (!nr_pages)
return 0;
/*
* Need extra space if node range is not aligned with
* MAX_ORDER_NR_PAGES. When page allocator's buddy algorithm
* checks buddy's status, range could be out of exact node range.
*/
if (!IS_ALIGNED(node_start_pfn(nid), MAX_ORDER_NR_PAGES) ||
!IS_ALIGNED(node_end_pfn(nid), MAX_ORDER_NR_PAGES))
nr_pages += MAX_ORDER_NR_PAGES;
table_size = page_ext_size * nr_pages;
base = memblock_alloc_try_nid(
table_size, PAGE_SIZE, __pa(MAX_DMA_ADDRESS),
MEMBLOCK_ALLOC_ACCESSIBLE, nid);
if (!base)
return -ENOMEM;
NODE_DATA(nid)->node_page_ext = base;
total_usage += table_size;
return 0;
}
void __init page_ext_init_flatmem(void)
{
int nid, fail;
if (!invoke_need_callbacks())
return;
for_each_online_node(nid) {
fail = alloc_node_page_ext(nid);
if (fail)
goto fail;
}
pr_info("allocated %ld bytes of page_ext\n", total_usage);
return;
fail:
pr_crit("allocation of page_ext failed.\n");
panic("Out of memory");
}
#else /* CONFIG_SPARSEMEM */
static bool page_ext_invalid(struct page_ext *page_ext)
{
return !page_ext || (((unsigned long)page_ext & PAGE_EXT_INVALID) == PAGE_EXT_INVALID);
}
static struct page_ext *lookup_page_ext(const struct page *page)
{
unsigned long pfn = page_to_pfn(page);
struct mem_section *section = __pfn_to_section(pfn);
struct page_ext *page_ext = READ_ONCE(section->page_ext);
WARN_ON_ONCE(!rcu_read_lock_held());
/*
* The sanity checks the page allocator does upon freeing a
* page can reach here before the page_ext arrays are
* allocated when feeding a range of pages to the allocator
* for the first time during bootup or memory hotplug.
*/
if (page_ext_invalid(page_ext))
return NULL;
return get_entry(page_ext, pfn);
}
static void *__meminit alloc_page_ext(size_t size, int nid)
{
gfp_t flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN;
void *addr = NULL;
addr = alloc_pages_exact_nid(nid, size, flags);
if (addr) {
kmemleak_alloc(addr, size, 1, flags);
return addr;
}
addr = vzalloc_node(size, nid);
return addr;
}
static int __meminit init_section_page_ext(unsigned long pfn, int nid)
{
struct mem_section *section;
struct page_ext *base;
unsigned long table_size;
section = __pfn_to_section(pfn);
if (section->page_ext)
return 0;
table_size = page_ext_size * PAGES_PER_SECTION;
base = alloc_page_ext(table_size, nid);
/*
* The value stored in section->page_ext is (base - pfn)
* and it does not point to the memory block allocated above,
* causing kmemleak false positives.
*/
kmemleak_not_leak(base);
if (!base) {
pr_err("page ext allocation failure\n");
return -ENOMEM;
}
/*
* The passed "pfn" may not be aligned to SECTION. For the calculation
* we need to apply a mask.
*/
pfn &= PAGE_SECTION_MASK;
section->page_ext = (void *)base - page_ext_size * pfn;
total_usage += table_size;
return 0;
}
static void free_page_ext(void *addr)
{
if (is_vmalloc_addr(addr)) {
vfree(addr);
} else {
struct page *page = virt_to_page(addr);
size_t table_size;
table_size = page_ext_size * PAGES_PER_SECTION;
BUG_ON(PageReserved(page));
kmemleak_free(addr);
free_pages_exact(addr, table_size);
}
}
static void __free_page_ext(unsigned long pfn)
{
struct mem_section *ms;
struct page_ext *base;
ms = __pfn_to_section(pfn);
if (!ms || !ms->page_ext)
return;
base = READ_ONCE(ms->page_ext);
/*
* page_ext here can be valid while doing the roll back
* operation in online_page_ext().
*/
if (page_ext_invalid(base))
base = (void *)base - PAGE_EXT_INVALID;
WRITE_ONCE(ms->page_ext, NULL);
base = get_entry(base, pfn);
free_page_ext(base);
}
static void __invalidate_page_ext(unsigned long pfn)
{
struct mem_section *ms;
void *val;
ms = __pfn_to_section(pfn);
if (!ms || !ms->page_ext)
return;
val = (void *)ms->page_ext + PAGE_EXT_INVALID;
WRITE_ONCE(ms->page_ext, val);
}
static int __meminit online_page_ext(unsigned long start_pfn,
unsigned long nr_pages,
int nid)
{
unsigned long start, end, pfn;
int fail = 0;
start = SECTION_ALIGN_DOWN(start_pfn);
end = SECTION_ALIGN_UP(start_pfn + nr_pages);
if (nid == NUMA_NO_NODE) {
/*
* In this case, "nid" already exists and contains valid memory.
* "start_pfn" passed to us is a pfn which is an arg for
* online__pages(), and start_pfn should exist.
*/
nid = pfn_to_nid(start_pfn);
VM_BUG_ON(!node_online(nid));
}
for (pfn = start; !fail && pfn < end; pfn += PAGES_PER_SECTION)
fail = init_section_page_ext(pfn, nid);
if (!fail)
return 0;
/* rollback */
end = pfn - PAGES_PER_SECTION;
for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
__free_page_ext(pfn);
return -ENOMEM;
}
static void __meminit offline_page_ext(unsigned long start_pfn,
unsigned long nr_pages)
{
unsigned long start, end, pfn;
start = SECTION_ALIGN_DOWN(start_pfn);
end = SECTION_ALIGN_UP(start_pfn + nr_pages);
/*
* Freeing of page_ext is done in 3 steps to avoid
* use-after-free of it:
* 1) Traverse all the sections and mark their page_ext
* as invalid.
* 2) Wait for all the existing users of page_ext who
* started before invalidation to finish.
* 3) Free the page_ext.
*/
for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
__invalidate_page_ext(pfn);
synchronize_rcu();
for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
__free_page_ext(pfn);
}
static int __meminit page_ext_callback(struct notifier_block *self,
unsigned long action, void *arg)
{
struct memory_notify *mn = arg;
int ret = 0;
switch (action) {
case MEM_GOING_ONLINE:
ret = online_page_ext(mn->start_pfn,
mn->nr_pages, mn->status_change_nid);
break;
case MEM_OFFLINE:
offline_page_ext(mn->start_pfn,
mn->nr_pages);
break;
case MEM_CANCEL_ONLINE:
offline_page_ext(mn->start_pfn,
mn->nr_pages);
break;
case MEM_GOING_OFFLINE:
break;
case MEM_ONLINE:
case MEM_CANCEL_OFFLINE:
break;
}
return notifier_from_errno(ret);
}
void __init page_ext_init(void)
{
unsigned long pfn;
int nid;
if (!invoke_need_callbacks())
return;
for_each_node_state(nid, N_MEMORY) {
unsigned long start_pfn, end_pfn;
start_pfn = node_start_pfn(nid);
end_pfn = node_end_pfn(nid);
/*
* start_pfn and end_pfn may not be aligned to SECTION and the
* page->flags of out of node pages are not initialized. So we
* scan [start_pfn, the biggest section's pfn < end_pfn) here.
*/
for (pfn = start_pfn; pfn < end_pfn;
pfn = ALIGN(pfn + 1, PAGES_PER_SECTION)) {
if (!pfn_valid(pfn))
continue;
/*
* Nodes's pfns can be overlapping.
* We know some arch can have a nodes layout such as
* -------------pfn-------------->
* N0 | N1 | N2 | N0 | N1 | N2|....
*/
if (pfn_to_nid(pfn) != nid)
continue;
if (init_section_page_ext(pfn, nid))
goto oom;
cond_resched();
}
}
hotplug_memory_notifier(page_ext_callback, DEFAULT_CALLBACK_PRI);
pr_info("allocated %ld bytes of page_ext\n", total_usage);
invoke_init_callbacks();
return;
oom:
panic("Out of memory");
}
void __meminit pgdat_page_ext_init(struct pglist_data *pgdat)
{
}
#endif
/**
* page_ext_get() - Get the extended information for a page.
* @page: The page we're interested in.
*
* Ensures that the page_ext will remain valid until page_ext_put()
* is called.
*
* Return: NULL if no page_ext exists for this page.
* Context: Any context. Caller may not sleep until they have called
* page_ext_put().
*/
struct page_ext *page_ext_get(struct page *page)
{
struct page_ext *page_ext;
rcu_read_lock();
page_ext = lookup_page_ext(page);
if (!page_ext) {
rcu_read_unlock();
return NULL;
}
return page_ext;
}
/**
* page_ext_put() - Working with page extended information is done.
* @page_ext: Page extended information received from page_ext_get().
*
* The page extended information of the page may not be valid after this
* function is called.
*
* Return: None.
* Context: Any context with corresponding page_ext_get() is called.
*/
void page_ext_put(struct page_ext *page_ext)
{
if (unlikely(!page_ext))
return;
rcu_read_unlock();
}
| linux-master | mm/page_ext.c |
// SPDX-License-Identifier: GPL-2.0
/*
* CMA SysFS Interface
*
* Copyright (c) 2021 Minchan Kim <[email protected]>
*/
#include <linux/cma.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include "cma.h"
#define CMA_ATTR_RO(_name) \
static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
void cma_sysfs_account_success_pages(struct cma *cma, unsigned long nr_pages)
{
atomic64_add(nr_pages, &cma->nr_pages_succeeded);
}
void cma_sysfs_account_fail_pages(struct cma *cma, unsigned long nr_pages)
{
atomic64_add(nr_pages, &cma->nr_pages_failed);
}
static inline struct cma *cma_from_kobj(struct kobject *kobj)
{
return container_of(kobj, struct cma_kobject, kobj)->cma;
}
static ssize_t alloc_pages_success_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct cma *cma = cma_from_kobj(kobj);
return sysfs_emit(buf, "%llu\n",
atomic64_read(&cma->nr_pages_succeeded));
}
CMA_ATTR_RO(alloc_pages_success);
static ssize_t alloc_pages_fail_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct cma *cma = cma_from_kobj(kobj);
return sysfs_emit(buf, "%llu\n", atomic64_read(&cma->nr_pages_failed));
}
CMA_ATTR_RO(alloc_pages_fail);
static void cma_kobj_release(struct kobject *kobj)
{
struct cma *cma = cma_from_kobj(kobj);
struct cma_kobject *cma_kobj = cma->cma_kobj;
kfree(cma_kobj);
cma->cma_kobj = NULL;
}
static struct attribute *cma_attrs[] = {
&alloc_pages_success_attr.attr,
&alloc_pages_fail_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(cma);
static const struct kobj_type cma_ktype = {
.release = cma_kobj_release,
.sysfs_ops = &kobj_sysfs_ops,
.default_groups = cma_groups,
};
static int __init cma_sysfs_init(void)
{
struct kobject *cma_kobj_root;
struct cma_kobject *cma_kobj;
struct cma *cma;
int i, err;
cma_kobj_root = kobject_create_and_add("cma", mm_kobj);
if (!cma_kobj_root)
return -ENOMEM;
for (i = 0; i < cma_area_count; i++) {
cma_kobj = kzalloc(sizeof(*cma_kobj), GFP_KERNEL);
if (!cma_kobj) {
err = -ENOMEM;
goto out;
}
cma = &cma_areas[i];
cma->cma_kobj = cma_kobj;
cma_kobj->cma = cma;
err = kobject_init_and_add(&cma_kobj->kobj, &cma_ktype,
cma_kobj_root, "%s", cma->name);
if (err) {
kobject_put(&cma_kobj->kobj);
goto out;
}
}
return 0;
out:
while (--i >= 0) {
cma = &cma_areas[i];
kobject_put(&cma->cma_kobj->kobj);
}
kobject_put(cma_kobj_root);
return err;
}
subsys_initcall(cma_sysfs_init);
| linux-master | mm/cma_sysfs.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/fault-inject.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include "slab.h"
static struct {
struct fault_attr attr;
bool ignore_gfp_reclaim;
bool cache_filter;
} failslab = {
.attr = FAULT_ATTR_INITIALIZER,
.ignore_gfp_reclaim = true,
.cache_filter = false,
};
bool __should_failslab(struct kmem_cache *s, gfp_t gfpflags)
{
int flags = 0;
/* No fault-injection for bootstrap cache */
if (unlikely(s == kmem_cache))
return false;
if (gfpflags & __GFP_NOFAIL)
return false;
if (failslab.ignore_gfp_reclaim &&
(gfpflags & __GFP_DIRECT_RECLAIM))
return false;
if (failslab.cache_filter && !(s->flags & SLAB_FAILSLAB))
return false;
/*
* In some cases, it expects to specify __GFP_NOWARN
* to avoid printing any information(not just a warning),
* thus avoiding deadlocks. See commit 6b9dbedbe349 for
* details.
*/
if (gfpflags & __GFP_NOWARN)
flags |= FAULT_NOWARN;
return should_fail_ex(&failslab.attr, s->object_size, flags);
}
static int __init setup_failslab(char *str)
{
return setup_fault_attr(&failslab.attr, str);
}
__setup("failslab=", setup_failslab);
#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
static int __init failslab_debugfs_init(void)
{
struct dentry *dir;
umode_t mode = S_IFREG | 0600;
dir = fault_create_debugfs_attr("failslab", NULL, &failslab.attr);
if (IS_ERR(dir))
return PTR_ERR(dir);
debugfs_create_bool("ignore-gfp-wait", mode, dir,
&failslab.ignore_gfp_reclaim);
debugfs_create_bool("cache-filter", mode, dir,
&failslab.cache_filter);
return 0;
}
late_initcall(failslab_debugfs_init);
#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
| linux-master | mm/failslab.c |
// SPDX-License-Identifier: GPL-2.0
/* Copyright(c) 2015 Intel Corporation. All rights reserved. */
#include <linux/device.h>
#include <linux/io.h>
#include <linux/kasan.h>
#include <linux/memory_hotplug.h>
#include <linux/memremap.h>
#include <linux/pfn_t.h>
#include <linux/swap.h>
#include <linux/mmzone.h>
#include <linux/swapops.h>
#include <linux/types.h>
#include <linux/wait_bit.h>
#include <linux/xarray.h>
#include "internal.h"
static DEFINE_XARRAY(pgmap_array);
/*
* The memremap() and memremap_pages() interfaces are alternately used
* to map persistent memory namespaces. These interfaces place different
* constraints on the alignment and size of the mapping (namespace).
* memremap() can map individual PAGE_SIZE pages. memremap_pages() can
* only map subsections (2MB), and at least one architecture (PowerPC)
* the minimum mapping granularity of memremap_pages() is 16MB.
*
* The role of memremap_compat_align() is to communicate the minimum
* arch supported alignment of a namespace such that it can freely
* switch modes without violating the arch constraint. Namely, do not
* allow a namespace to be PAGE_SIZE aligned since that namespace may be
* reconfigured into a mode that requires SUBSECTION_SIZE alignment.
*/
#ifndef CONFIG_ARCH_HAS_MEMREMAP_COMPAT_ALIGN
unsigned long memremap_compat_align(void)
{
return SUBSECTION_SIZE;
}
EXPORT_SYMBOL_GPL(memremap_compat_align);
#endif
#ifdef CONFIG_FS_DAX
DEFINE_STATIC_KEY_FALSE(devmap_managed_key);
EXPORT_SYMBOL(devmap_managed_key);
static void devmap_managed_enable_put(struct dev_pagemap *pgmap)
{
if (pgmap->type == MEMORY_DEVICE_FS_DAX)
static_branch_dec(&devmap_managed_key);
}
static void devmap_managed_enable_get(struct dev_pagemap *pgmap)
{
if (pgmap->type == MEMORY_DEVICE_FS_DAX)
static_branch_inc(&devmap_managed_key);
}
#else
static void devmap_managed_enable_get(struct dev_pagemap *pgmap)
{
}
static void devmap_managed_enable_put(struct dev_pagemap *pgmap)
{
}
#endif /* CONFIG_FS_DAX */
static void pgmap_array_delete(struct range *range)
{
xa_store_range(&pgmap_array, PHYS_PFN(range->start), PHYS_PFN(range->end),
NULL, GFP_KERNEL);
synchronize_rcu();
}
static unsigned long pfn_first(struct dev_pagemap *pgmap, int range_id)
{
struct range *range = &pgmap->ranges[range_id];
unsigned long pfn = PHYS_PFN(range->start);
if (range_id)
return pfn;
return pfn + vmem_altmap_offset(pgmap_altmap(pgmap));
}
bool pgmap_pfn_valid(struct dev_pagemap *pgmap, unsigned long pfn)
{
int i;
for (i = 0; i < pgmap->nr_range; i++) {
struct range *range = &pgmap->ranges[i];
if (pfn >= PHYS_PFN(range->start) &&
pfn <= PHYS_PFN(range->end))
return pfn >= pfn_first(pgmap, i);
}
return false;
}
static unsigned long pfn_end(struct dev_pagemap *pgmap, int range_id)
{
const struct range *range = &pgmap->ranges[range_id];
return (range->start + range_len(range)) >> PAGE_SHIFT;
}
static unsigned long pfn_len(struct dev_pagemap *pgmap, unsigned long range_id)
{
return (pfn_end(pgmap, range_id) -
pfn_first(pgmap, range_id)) >> pgmap->vmemmap_shift;
}
static void pageunmap_range(struct dev_pagemap *pgmap, int range_id)
{
struct range *range = &pgmap->ranges[range_id];
struct page *first_page;
/* make sure to access a memmap that was actually initialized */
first_page = pfn_to_page(pfn_first(pgmap, range_id));
/* pages are dead and unused, undo the arch mapping */
mem_hotplug_begin();
remove_pfn_range_from_zone(page_zone(first_page), PHYS_PFN(range->start),
PHYS_PFN(range_len(range)));
if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
__remove_pages(PHYS_PFN(range->start),
PHYS_PFN(range_len(range)), NULL);
} else {
arch_remove_memory(range->start, range_len(range),
pgmap_altmap(pgmap));
kasan_remove_zero_shadow(__va(range->start), range_len(range));
}
mem_hotplug_done();
untrack_pfn(NULL, PHYS_PFN(range->start), range_len(range), true);
pgmap_array_delete(range);
}
void memunmap_pages(struct dev_pagemap *pgmap)
{
int i;
percpu_ref_kill(&pgmap->ref);
if (pgmap->type != MEMORY_DEVICE_PRIVATE &&
pgmap->type != MEMORY_DEVICE_COHERENT)
for (i = 0; i < pgmap->nr_range; i++)
percpu_ref_put_many(&pgmap->ref, pfn_len(pgmap, i));
wait_for_completion(&pgmap->done);
for (i = 0; i < pgmap->nr_range; i++)
pageunmap_range(pgmap, i);
percpu_ref_exit(&pgmap->ref);
WARN_ONCE(pgmap->altmap.alloc, "failed to free all reserved pages\n");
devmap_managed_enable_put(pgmap);
}
EXPORT_SYMBOL_GPL(memunmap_pages);
static void devm_memremap_pages_release(void *data)
{
memunmap_pages(data);
}
static void dev_pagemap_percpu_release(struct percpu_ref *ref)
{
struct dev_pagemap *pgmap = container_of(ref, struct dev_pagemap, ref);
complete(&pgmap->done);
}
static int pagemap_range(struct dev_pagemap *pgmap, struct mhp_params *params,
int range_id, int nid)
{
const bool is_private = pgmap->type == MEMORY_DEVICE_PRIVATE;
struct range *range = &pgmap->ranges[range_id];
struct dev_pagemap *conflict_pgmap;
int error, is_ram;
if (WARN_ONCE(pgmap_altmap(pgmap) && range_id > 0,
"altmap not supported for multiple ranges\n"))
return -EINVAL;
conflict_pgmap = get_dev_pagemap(PHYS_PFN(range->start), NULL);
if (conflict_pgmap) {
WARN(1, "Conflicting mapping in same section\n");
put_dev_pagemap(conflict_pgmap);
return -ENOMEM;
}
conflict_pgmap = get_dev_pagemap(PHYS_PFN(range->end), NULL);
if (conflict_pgmap) {
WARN(1, "Conflicting mapping in same section\n");
put_dev_pagemap(conflict_pgmap);
return -ENOMEM;
}
is_ram = region_intersects(range->start, range_len(range),
IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
if (is_ram != REGION_DISJOINT) {
WARN_ONCE(1, "attempted on %s region %#llx-%#llx\n",
is_ram == REGION_MIXED ? "mixed" : "ram",
range->start, range->end);
return -ENXIO;
}
error = xa_err(xa_store_range(&pgmap_array, PHYS_PFN(range->start),
PHYS_PFN(range->end), pgmap, GFP_KERNEL));
if (error)
return error;
if (nid < 0)
nid = numa_mem_id();
error = track_pfn_remap(NULL, ¶ms->pgprot, PHYS_PFN(range->start), 0,
range_len(range));
if (error)
goto err_pfn_remap;
if (!mhp_range_allowed(range->start, range_len(range), !is_private)) {
error = -EINVAL;
goto err_kasan;
}
mem_hotplug_begin();
/*
* For device private memory we call add_pages() as we only need to
* allocate and initialize struct page for the device memory. More-
* over the device memory is un-accessible thus we do not want to
* create a linear mapping for the memory like arch_add_memory()
* would do.
*
* For all other device memory types, which are accessible by
* the CPU, we do want the linear mapping and thus use
* arch_add_memory().
*/
if (is_private) {
error = add_pages(nid, PHYS_PFN(range->start),
PHYS_PFN(range_len(range)), params);
} else {
error = kasan_add_zero_shadow(__va(range->start), range_len(range));
if (error) {
mem_hotplug_done();
goto err_kasan;
}
error = arch_add_memory(nid, range->start, range_len(range),
params);
}
if (!error) {
struct zone *zone;
zone = &NODE_DATA(nid)->node_zones[ZONE_DEVICE];
move_pfn_range_to_zone(zone, PHYS_PFN(range->start),
PHYS_PFN(range_len(range)), params->altmap,
MIGRATE_MOVABLE);
}
mem_hotplug_done();
if (error)
goto err_add_memory;
/*
* Initialization of the pages has been deferred until now in order
* to allow us to do the work while not holding the hotplug lock.
*/
memmap_init_zone_device(&NODE_DATA(nid)->node_zones[ZONE_DEVICE],
PHYS_PFN(range->start),
PHYS_PFN(range_len(range)), pgmap);
if (pgmap->type != MEMORY_DEVICE_PRIVATE &&
pgmap->type != MEMORY_DEVICE_COHERENT)
percpu_ref_get_many(&pgmap->ref, pfn_len(pgmap, range_id));
return 0;
err_add_memory:
if (!is_private)
kasan_remove_zero_shadow(__va(range->start), range_len(range));
err_kasan:
untrack_pfn(NULL, PHYS_PFN(range->start), range_len(range), true);
err_pfn_remap:
pgmap_array_delete(range);
return error;
}
/*
* Not device managed version of devm_memremap_pages, undone by
* memunmap_pages(). Please use devm_memremap_pages if you have a struct
* device available.
*/
void *memremap_pages(struct dev_pagemap *pgmap, int nid)
{
struct mhp_params params = {
.altmap = pgmap_altmap(pgmap),
.pgmap = pgmap,
.pgprot = PAGE_KERNEL,
};
const int nr_range = pgmap->nr_range;
int error, i;
if (WARN_ONCE(!nr_range, "nr_range must be specified\n"))
return ERR_PTR(-EINVAL);
switch (pgmap->type) {
case MEMORY_DEVICE_PRIVATE:
if (!IS_ENABLED(CONFIG_DEVICE_PRIVATE)) {
WARN(1, "Device private memory not supported\n");
return ERR_PTR(-EINVAL);
}
if (!pgmap->ops || !pgmap->ops->migrate_to_ram) {
WARN(1, "Missing migrate_to_ram method\n");
return ERR_PTR(-EINVAL);
}
if (!pgmap->ops->page_free) {
WARN(1, "Missing page_free method\n");
return ERR_PTR(-EINVAL);
}
if (!pgmap->owner) {
WARN(1, "Missing owner\n");
return ERR_PTR(-EINVAL);
}
break;
case MEMORY_DEVICE_COHERENT:
if (!pgmap->ops->page_free) {
WARN(1, "Missing page_free method\n");
return ERR_PTR(-EINVAL);
}
if (!pgmap->owner) {
WARN(1, "Missing owner\n");
return ERR_PTR(-EINVAL);
}
break;
case MEMORY_DEVICE_FS_DAX:
if (IS_ENABLED(CONFIG_FS_DAX_LIMITED)) {
WARN(1, "File system DAX not supported\n");
return ERR_PTR(-EINVAL);
}
params.pgprot = pgprot_decrypted(params.pgprot);
break;
case MEMORY_DEVICE_GENERIC:
break;
case MEMORY_DEVICE_PCI_P2PDMA:
params.pgprot = pgprot_noncached(params.pgprot);
break;
default:
WARN(1, "Invalid pgmap type %d\n", pgmap->type);
break;
}
init_completion(&pgmap->done);
error = percpu_ref_init(&pgmap->ref, dev_pagemap_percpu_release, 0,
GFP_KERNEL);
if (error)
return ERR_PTR(error);
devmap_managed_enable_get(pgmap);
/*
* Clear the pgmap nr_range as it will be incremented for each
* successfully processed range. This communicates how many
* regions to unwind in the abort case.
*/
pgmap->nr_range = 0;
error = 0;
for (i = 0; i < nr_range; i++) {
error = pagemap_range(pgmap, ¶ms, i, nid);
if (error)
break;
pgmap->nr_range++;
}
if (i < nr_range) {
memunmap_pages(pgmap);
pgmap->nr_range = nr_range;
return ERR_PTR(error);
}
return __va(pgmap->ranges[0].start);
}
EXPORT_SYMBOL_GPL(memremap_pages);
/**
* devm_memremap_pages - remap and provide memmap backing for the given resource
* @dev: hosting device for @res
* @pgmap: pointer to a struct dev_pagemap
*
* Notes:
* 1/ At a minimum the range and type members of @pgmap must be initialized
* by the caller before passing it to this function
*
* 2/ The altmap field may optionally be initialized, in which case
* PGMAP_ALTMAP_VALID must be set in pgmap->flags.
*
* 3/ The ref field may optionally be provided, in which pgmap->ref must be
* 'live' on entry and will be killed and reaped at
* devm_memremap_pages_release() time, or if this routine fails.
*
* 4/ range is expected to be a host memory range that could feasibly be
* treated as a "System RAM" range, i.e. not a device mmio range, but
* this is not enforced.
*/
void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
{
int error;
void *ret;
ret = memremap_pages(pgmap, dev_to_node(dev));
if (IS_ERR(ret))
return ret;
error = devm_add_action_or_reset(dev, devm_memremap_pages_release,
pgmap);
if (error)
return ERR_PTR(error);
return ret;
}
EXPORT_SYMBOL_GPL(devm_memremap_pages);
void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap)
{
devm_release_action(dev, devm_memremap_pages_release, pgmap);
}
EXPORT_SYMBOL_GPL(devm_memunmap_pages);
unsigned long vmem_altmap_offset(struct vmem_altmap *altmap)
{
/* number of pfns from base where pfn_to_page() is valid */
if (altmap)
return altmap->reserve + altmap->free;
return 0;
}
void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns)
{
altmap->alloc -= nr_pfns;
}
/**
* get_dev_pagemap() - take a new live reference on the dev_pagemap for @pfn
* @pfn: page frame number to lookup page_map
* @pgmap: optional known pgmap that already has a reference
*
* If @pgmap is non-NULL and covers @pfn it will be returned as-is. If @pgmap
* is non-NULL but does not cover @pfn the reference to it will be released.
*/
struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
struct dev_pagemap *pgmap)
{
resource_size_t phys = PFN_PHYS(pfn);
/*
* In the cached case we're already holding a live reference.
*/
if (pgmap) {
if (phys >= pgmap->range.start && phys <= pgmap->range.end)
return pgmap;
put_dev_pagemap(pgmap);
}
/* fall back to slow path lookup */
rcu_read_lock();
pgmap = xa_load(&pgmap_array, PHYS_PFN(phys));
if (pgmap && !percpu_ref_tryget_live_rcu(&pgmap->ref))
pgmap = NULL;
rcu_read_unlock();
return pgmap;
}
EXPORT_SYMBOL_GPL(get_dev_pagemap);
void free_zone_device_page(struct page *page)
{
if (WARN_ON_ONCE(!page->pgmap->ops || !page->pgmap->ops->page_free))
return;
mem_cgroup_uncharge(page_folio(page));
/*
* Note: we don't expect anonymous compound pages yet. Once supported
* and we could PTE-map them similar to THP, we'd have to clear
* PG_anon_exclusive on all tail pages.
*/
VM_BUG_ON_PAGE(PageAnon(page) && PageCompound(page), page);
if (PageAnon(page))
__ClearPageAnonExclusive(page);
/*
* When a device managed page is freed, the page->mapping field
* may still contain a (stale) mapping value. For example, the
* lower bits of page->mapping may still identify the page as an
* anonymous page. Ultimately, this entire field is just stale
* and wrong, and it will cause errors if not cleared. One
* example is:
*
* migrate_vma_pages()
* migrate_vma_insert_page()
* page_add_new_anon_rmap()
* __page_set_anon_rmap()
* ...checks page->mapping, via PageAnon(page) call,
* and incorrectly concludes that the page is an
* anonymous page. Therefore, it incorrectly,
* silently fails to set up the new anon rmap.
*
* For other types of ZONE_DEVICE pages, migration is either
* handled differently or not done at all, so there is no need
* to clear page->mapping.
*/
page->mapping = NULL;
page->pgmap->ops->page_free(page);
if (page->pgmap->type != MEMORY_DEVICE_PRIVATE &&
page->pgmap->type != MEMORY_DEVICE_COHERENT)
/*
* Reset the page count to 1 to prepare for handing out the page
* again.
*/
set_page_count(page, 1);
else
put_dev_pagemap(page->pgmap);
}
void zone_device_page_init(struct page *page)
{
/*
* Drivers shouldn't be allocating pages after calling
* memunmap_pages().
*/
WARN_ON_ONCE(!percpu_ref_tryget_live(&page->pgmap->ref));
set_page_count(page, 1);
lock_page(page);
}
EXPORT_SYMBOL_GPL(zone_device_page_init);
#ifdef CONFIG_FS_DAX
bool __put_devmap_managed_page_refs(struct page *page, int refs)
{
if (page->pgmap->type != MEMORY_DEVICE_FS_DAX)
return false;
/*
* fsdax page refcounts are 1-based, rather than 0-based: if
* refcount is 1, then the page is free and the refcount is
* stable because nobody holds a reference on the page.
*/
if (page_ref_sub_return(page, refs) == 1)
wake_up_var(&page->_refcount);
return true;
}
EXPORT_SYMBOL(__put_devmap_managed_page_refs);
#endif /* CONFIG_FS_DAX */
| linux-master | mm/memremap.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* In memory quota format relies on quota infrastructure to store dquot
* information for us. While conventional quota formats for file systems
* with persistent storage can load quota information into dquot from the
* storage on-demand and hence quota dquot shrinker can free any dquot
* that is not currently being used, it must be avoided here. Otherwise we
* can lose valuable information, user provided limits, because there is
* no persistent storage to load the information from afterwards.
*
* One information that in-memory quota format needs to keep track of is
* a sorted list of ids for each quota type. This is done by utilizing
* an rb tree which root is stored in mem_dqinfo->dqi_priv for each quota
* type.
*
* This format can be used to support quota on file system without persistent
* storage such as tmpfs.
*
* Author: Lukas Czerner <[email protected]>
* Carlos Maiolino <[email protected]>
*
* Copyright (C) 2023 Red Hat, Inc.
*/
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/rbtree.h>
#include <linux/shmem_fs.h>
#include <linux/quotaops.h>
#include <linux/quota.h>
#ifdef CONFIG_TMPFS_QUOTA
/*
* The following constants define the amount of time given a user
* before the soft limits are treated as hard limits (usually resulting
* in an allocation failure). The timer is started when the user crosses
* their soft limit, it is reset when they go below their soft limit.
*/
#define SHMEM_MAX_IQ_TIME 604800 /* (7*24*60*60) 1 week */
#define SHMEM_MAX_DQ_TIME 604800 /* (7*24*60*60) 1 week */
struct quota_id {
struct rb_node node;
qid_t id;
qsize_t bhardlimit;
qsize_t bsoftlimit;
qsize_t ihardlimit;
qsize_t isoftlimit;
};
static int shmem_check_quota_file(struct super_block *sb, int type)
{
/* There is no real quota file, nothing to do */
return 1;
}
/*
* There is no real quota file. Just allocate rb_root for quota ids and
* set limits
*/
static int shmem_read_file_info(struct super_block *sb, int type)
{
struct quota_info *dqopt = sb_dqopt(sb);
struct mem_dqinfo *info = &dqopt->info[type];
info->dqi_priv = kzalloc(sizeof(struct rb_root), GFP_NOFS);
if (!info->dqi_priv)
return -ENOMEM;
info->dqi_max_spc_limit = SHMEM_QUOTA_MAX_SPC_LIMIT;
info->dqi_max_ino_limit = SHMEM_QUOTA_MAX_INO_LIMIT;
info->dqi_bgrace = SHMEM_MAX_DQ_TIME;
info->dqi_igrace = SHMEM_MAX_IQ_TIME;
info->dqi_flags = 0;
return 0;
}
static int shmem_write_file_info(struct super_block *sb, int type)
{
/* There is no real quota file, nothing to do */
return 0;
}
/*
* Free all the quota_id entries in the rb tree and rb_root.
*/
static int shmem_free_file_info(struct super_block *sb, int type)
{
struct mem_dqinfo *info = &sb_dqopt(sb)->info[type];
struct rb_root *root = info->dqi_priv;
struct quota_id *entry;
struct rb_node *node;
info->dqi_priv = NULL;
node = rb_first(root);
while (node) {
entry = rb_entry(node, struct quota_id, node);
node = rb_next(&entry->node);
rb_erase(&entry->node, root);
kfree(entry);
}
kfree(root);
return 0;
}
static int shmem_get_next_id(struct super_block *sb, struct kqid *qid)
{
struct mem_dqinfo *info = sb_dqinfo(sb, qid->type);
struct rb_node *node = ((struct rb_root *)info->dqi_priv)->rb_node;
qid_t id = from_kqid(&init_user_ns, *qid);
struct quota_info *dqopt = sb_dqopt(sb);
struct quota_id *entry = NULL;
int ret = 0;
if (!sb_has_quota_active(sb, qid->type))
return -ESRCH;
down_read(&dqopt->dqio_sem);
while (node) {
entry = rb_entry(node, struct quota_id, node);
if (id < entry->id)
node = node->rb_left;
else if (id > entry->id)
node = node->rb_right;
else
goto got_next_id;
}
if (!entry) {
ret = -ENOENT;
goto out_unlock;
}
if (id > entry->id) {
node = rb_next(&entry->node);
if (!node) {
ret = -ENOENT;
goto out_unlock;
}
entry = rb_entry(node, struct quota_id, node);
}
got_next_id:
*qid = make_kqid(&init_user_ns, qid->type, entry->id);
out_unlock:
up_read(&dqopt->dqio_sem);
return ret;
}
/*
* Load dquot with limits from existing entry, or create the new entry if
* it does not exist.
*/
static int shmem_acquire_dquot(struct dquot *dquot)
{
struct mem_dqinfo *info = sb_dqinfo(dquot->dq_sb, dquot->dq_id.type);
struct rb_node **n = &((struct rb_root *)info->dqi_priv)->rb_node;
struct shmem_sb_info *sbinfo = dquot->dq_sb->s_fs_info;
struct rb_node *parent = NULL, *new_node = NULL;
struct quota_id *new_entry, *entry;
qid_t id = from_kqid(&init_user_ns, dquot->dq_id);
struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
int ret = 0;
mutex_lock(&dquot->dq_lock);
down_write(&dqopt->dqio_sem);
while (*n) {
parent = *n;
entry = rb_entry(parent, struct quota_id, node);
if (id < entry->id)
n = &(*n)->rb_left;
else if (id > entry->id)
n = &(*n)->rb_right;
else
goto found;
}
/* We don't have entry for this id yet, create it */
new_entry = kzalloc(sizeof(struct quota_id), GFP_NOFS);
if (!new_entry) {
ret = -ENOMEM;
goto out_unlock;
}
new_entry->id = id;
if (dquot->dq_id.type == USRQUOTA) {
new_entry->bhardlimit = sbinfo->qlimits.usrquota_bhardlimit;
new_entry->ihardlimit = sbinfo->qlimits.usrquota_ihardlimit;
} else if (dquot->dq_id.type == GRPQUOTA) {
new_entry->bhardlimit = sbinfo->qlimits.grpquota_bhardlimit;
new_entry->ihardlimit = sbinfo->qlimits.grpquota_ihardlimit;
}
new_node = &new_entry->node;
rb_link_node(new_node, parent, n);
rb_insert_color(new_node, (struct rb_root *)info->dqi_priv);
entry = new_entry;
found:
/* Load the stored limits from the tree */
spin_lock(&dquot->dq_dqb_lock);
dquot->dq_dqb.dqb_bhardlimit = entry->bhardlimit;
dquot->dq_dqb.dqb_bsoftlimit = entry->bsoftlimit;
dquot->dq_dqb.dqb_ihardlimit = entry->ihardlimit;
dquot->dq_dqb.dqb_isoftlimit = entry->isoftlimit;
if (!dquot->dq_dqb.dqb_bhardlimit &&
!dquot->dq_dqb.dqb_bsoftlimit &&
!dquot->dq_dqb.dqb_ihardlimit &&
!dquot->dq_dqb.dqb_isoftlimit)
set_bit(DQ_FAKE_B, &dquot->dq_flags);
spin_unlock(&dquot->dq_dqb_lock);
/* Make sure flags update is visible after dquot has been filled */
smp_mb__before_atomic();
set_bit(DQ_ACTIVE_B, &dquot->dq_flags);
out_unlock:
up_write(&dqopt->dqio_sem);
mutex_unlock(&dquot->dq_lock);
return ret;
}
static bool shmem_is_empty_dquot(struct dquot *dquot)
{
struct shmem_sb_info *sbinfo = dquot->dq_sb->s_fs_info;
qsize_t bhardlimit;
qsize_t ihardlimit;
if (dquot->dq_id.type == USRQUOTA) {
bhardlimit = sbinfo->qlimits.usrquota_bhardlimit;
ihardlimit = sbinfo->qlimits.usrquota_ihardlimit;
} else if (dquot->dq_id.type == GRPQUOTA) {
bhardlimit = sbinfo->qlimits.grpquota_bhardlimit;
ihardlimit = sbinfo->qlimits.grpquota_ihardlimit;
}
if (test_bit(DQ_FAKE_B, &dquot->dq_flags) ||
(dquot->dq_dqb.dqb_curspace == 0 &&
dquot->dq_dqb.dqb_curinodes == 0 &&
dquot->dq_dqb.dqb_bhardlimit == bhardlimit &&
dquot->dq_dqb.dqb_ihardlimit == ihardlimit))
return true;
return false;
}
/*
* Store limits from dquot in the tree unless it's fake. If it is fake
* remove the id from the tree since there is no useful information in
* there.
*/
static int shmem_release_dquot(struct dquot *dquot)
{
struct mem_dqinfo *info = sb_dqinfo(dquot->dq_sb, dquot->dq_id.type);
struct rb_node *node = ((struct rb_root *)info->dqi_priv)->rb_node;
qid_t id = from_kqid(&init_user_ns, dquot->dq_id);
struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
struct quota_id *entry = NULL;
mutex_lock(&dquot->dq_lock);
/* Check whether we are not racing with some other dqget() */
if (dquot_is_busy(dquot))
goto out_dqlock;
down_write(&dqopt->dqio_sem);
while (node) {
entry = rb_entry(node, struct quota_id, node);
if (id < entry->id)
node = node->rb_left;
else if (id > entry->id)
node = node->rb_right;
else
goto found;
}
/* We should always find the entry in the rb tree */
WARN_ONCE(1, "quota id %u from dquot %p, not in rb tree!\n", id, dquot);
up_write(&dqopt->dqio_sem);
mutex_unlock(&dquot->dq_lock);
return -ENOENT;
found:
if (shmem_is_empty_dquot(dquot)) {
/* Remove entry from the tree */
rb_erase(&entry->node, info->dqi_priv);
kfree(entry);
} else {
/* Store the limits in the tree */
spin_lock(&dquot->dq_dqb_lock);
entry->bhardlimit = dquot->dq_dqb.dqb_bhardlimit;
entry->bsoftlimit = dquot->dq_dqb.dqb_bsoftlimit;
entry->ihardlimit = dquot->dq_dqb.dqb_ihardlimit;
entry->isoftlimit = dquot->dq_dqb.dqb_isoftlimit;
spin_unlock(&dquot->dq_dqb_lock);
}
clear_bit(DQ_ACTIVE_B, &dquot->dq_flags);
up_write(&dqopt->dqio_sem);
out_dqlock:
mutex_unlock(&dquot->dq_lock);
return 0;
}
static int shmem_mark_dquot_dirty(struct dquot *dquot)
{
return 0;
}
static int shmem_dquot_write_info(struct super_block *sb, int type)
{
return 0;
}
static const struct quota_format_ops shmem_format_ops = {
.check_quota_file = shmem_check_quota_file,
.read_file_info = shmem_read_file_info,
.write_file_info = shmem_write_file_info,
.free_file_info = shmem_free_file_info,
};
struct quota_format_type shmem_quota_format = {
.qf_fmt_id = QFMT_SHMEM,
.qf_ops = &shmem_format_ops,
.qf_owner = THIS_MODULE
};
const struct dquot_operations shmem_quota_operations = {
.acquire_dquot = shmem_acquire_dquot,
.release_dquot = shmem_release_dquot,
.alloc_dquot = dquot_alloc,
.destroy_dquot = dquot_destroy,
.write_info = shmem_dquot_write_info,
.mark_dirty = shmem_mark_dquot_dirty,
.get_next_id = shmem_get_next_id,
};
#endif /* CONFIG_TMPFS_QUOTA */
| linux-master | mm/shmem_quota.c |
// SPDX-License-Identifier: GPL-2.0-only
/* Inject a hwpoison memory failure on a arbitrary pfn */
#include <linux/module.h>
#include <linux/debugfs.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/pagemap.h>
#include <linux/hugetlb.h>
#include "internal.h"
static struct dentry *hwpoison_dir;
static int hwpoison_inject(void *data, u64 val)
{
unsigned long pfn = val;
struct page *p;
struct page *hpage;
int err;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (!pfn_valid(pfn))
return -ENXIO;
p = pfn_to_page(pfn);
hpage = compound_head(p);
if (!hwpoison_filter_enable)
goto inject;
shake_page(hpage);
/*
* This implies unable to support non-LRU pages except free page.
*/
if (!PageLRU(hpage) && !PageHuge(p) && !is_free_buddy_page(p))
return 0;
/*
* do a racy check to make sure PG_hwpoison will only be set for
* the targeted owner (or on a free page).
* memory_failure() will redo the check reliably inside page lock.
*/
err = hwpoison_filter(hpage);
if (err)
return 0;
inject:
pr_info("Injecting memory failure at pfn %#lx\n", pfn);
err = memory_failure(pfn, MF_SW_SIMULATED);
return (err == -EOPNOTSUPP) ? 0 : err;
}
static int hwpoison_unpoison(void *data, u64 val)
{
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
return unpoison_memory(val);
}
DEFINE_DEBUGFS_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n");
DEFINE_DEBUGFS_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n");
static void __exit pfn_inject_exit(void)
{
hwpoison_filter_enable = 0;
debugfs_remove_recursive(hwpoison_dir);
}
static int __init pfn_inject_init(void)
{
hwpoison_dir = debugfs_create_dir("hwpoison", NULL);
/*
* Note that the below poison/unpoison interfaces do not involve
* hardware status change, hence do not require hardware support.
* They are mainly for testing hwpoison in software level.
*/
debugfs_create_file("corrupt-pfn", 0200, hwpoison_dir, NULL,
&hwpoison_fops);
debugfs_create_file("unpoison-pfn", 0200, hwpoison_dir, NULL,
&unpoison_fops);
debugfs_create_u32("corrupt-filter-enable", 0600, hwpoison_dir,
&hwpoison_filter_enable);
debugfs_create_u32("corrupt-filter-dev-major", 0600, hwpoison_dir,
&hwpoison_filter_dev_major);
debugfs_create_u32("corrupt-filter-dev-minor", 0600, hwpoison_dir,
&hwpoison_filter_dev_minor);
debugfs_create_u64("corrupt-filter-flags-mask", 0600, hwpoison_dir,
&hwpoison_filter_flags_mask);
debugfs_create_u64("corrupt-filter-flags-value", 0600, hwpoison_dir,
&hwpoison_filter_flags_value);
#ifdef CONFIG_MEMCG
debugfs_create_u64("corrupt-filter-memcg", 0600, hwpoison_dir,
&hwpoison_filter_memcg);
#endif
return 0;
}
module_init(pfn_inject_init);
module_exit(pfn_inject_exit);
MODULE_LICENSE("GPL");
| linux-master | mm/hwpoison-inject.c |
/*
* Compatibility functions which bloat the callers too much to make inline.
* All of the callers of these functions should be converted to use folios
* eventually.
*/
#include <linux/migrate.h>
#include <linux/pagemap.h>
#include <linux/rmap.h>
#include <linux/swap.h>
#include "internal.h"
struct address_space *page_mapping(struct page *page)
{
return folio_mapping(page_folio(page));
}
EXPORT_SYMBOL(page_mapping);
void unlock_page(struct page *page)
{
return folio_unlock(page_folio(page));
}
EXPORT_SYMBOL(unlock_page);
void end_page_writeback(struct page *page)
{
return folio_end_writeback(page_folio(page));
}
EXPORT_SYMBOL(end_page_writeback);
void wait_on_page_writeback(struct page *page)
{
return folio_wait_writeback(page_folio(page));
}
EXPORT_SYMBOL_GPL(wait_on_page_writeback);
void wait_for_stable_page(struct page *page)
{
return folio_wait_stable(page_folio(page));
}
EXPORT_SYMBOL_GPL(wait_for_stable_page);
void mark_page_accessed(struct page *page)
{
folio_mark_accessed(page_folio(page));
}
EXPORT_SYMBOL(mark_page_accessed);
bool set_page_writeback(struct page *page)
{
return folio_start_writeback(page_folio(page));
}
EXPORT_SYMBOL(set_page_writeback);
bool set_page_dirty(struct page *page)
{
return folio_mark_dirty(page_folio(page));
}
EXPORT_SYMBOL(set_page_dirty);
int __set_page_dirty_nobuffers(struct page *page)
{
return filemap_dirty_folio(page_mapping(page), page_folio(page));
}
EXPORT_SYMBOL(__set_page_dirty_nobuffers);
bool clear_page_dirty_for_io(struct page *page)
{
return folio_clear_dirty_for_io(page_folio(page));
}
EXPORT_SYMBOL(clear_page_dirty_for_io);
bool redirty_page_for_writepage(struct writeback_control *wbc,
struct page *page)
{
return folio_redirty_for_writepage(wbc, page_folio(page));
}
EXPORT_SYMBOL(redirty_page_for_writepage);
void lru_cache_add_inactive_or_unevictable(struct page *page,
struct vm_area_struct *vma)
{
folio_add_lru_vma(page_folio(page), vma);
}
int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
pgoff_t index, gfp_t gfp)
{
return filemap_add_folio(mapping, page_folio(page), index, gfp);
}
EXPORT_SYMBOL(add_to_page_cache_lru);
noinline
struct page *pagecache_get_page(struct address_space *mapping, pgoff_t index,
fgf_t fgp_flags, gfp_t gfp)
{
struct folio *folio;
folio = __filemap_get_folio(mapping, index, fgp_flags, gfp);
if (IS_ERR(folio))
return NULL;
return folio_file_page(folio, index);
}
EXPORT_SYMBOL(pagecache_get_page);
struct page *grab_cache_page_write_begin(struct address_space *mapping,
pgoff_t index)
{
return pagecache_get_page(mapping, index, FGP_WRITEBEGIN,
mapping_gfp_mask(mapping));
}
EXPORT_SYMBOL(grab_cache_page_write_begin);
bool isolate_lru_page(struct page *page)
{
if (WARN_RATELIMIT(PageTail(page), "trying to isolate tail page"))
return false;
return folio_isolate_lru((struct folio *)page);
}
void putback_lru_page(struct page *page)
{
folio_putback_lru(page_folio(page));
}
#ifdef CONFIG_MMU
void page_add_new_anon_rmap(struct page *page, struct vm_area_struct *vma,
unsigned long address)
{
VM_BUG_ON_PAGE(PageTail(page), page);
return folio_add_new_anon_rmap((struct folio *)page, vma, address);
}
#endif
| linux-master | mm/folio-compat.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* mm/userfaultfd.c
*
* Copyright (C) 2015 Red Hat, Inc.
*/
#include <linux/mm.h>
#include <linux/sched/signal.h>
#include <linux/pagemap.h>
#include <linux/rmap.h>
#include <linux/swap.h>
#include <linux/swapops.h>
#include <linux/userfaultfd_k.h>
#include <linux/mmu_notifier.h>
#include <linux/hugetlb.h>
#include <linux/shmem_fs.h>
#include <asm/tlbflush.h>
#include <asm/tlb.h>
#include "internal.h"
static __always_inline
struct vm_area_struct *find_dst_vma(struct mm_struct *dst_mm,
unsigned long dst_start,
unsigned long len)
{
/*
* Make sure that the dst range is both valid and fully within a
* single existing vma.
*/
struct vm_area_struct *dst_vma;
dst_vma = find_vma(dst_mm, dst_start);
if (!range_in_vma(dst_vma, dst_start, dst_start + len))
return NULL;
/*
* Check the vma is registered in uffd, this is required to
* enforce the VM_MAYWRITE check done at uffd registration
* time.
*/
if (!dst_vma->vm_userfaultfd_ctx.ctx)
return NULL;
return dst_vma;
}
/* Check if dst_addr is outside of file's size. Must be called with ptl held. */
static bool mfill_file_over_size(struct vm_area_struct *dst_vma,
unsigned long dst_addr)
{
struct inode *inode;
pgoff_t offset, max_off;
if (!dst_vma->vm_file)
return false;
inode = dst_vma->vm_file->f_inode;
offset = linear_page_index(dst_vma, dst_addr);
max_off = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
return offset >= max_off;
}
/*
* Install PTEs, to map dst_addr (within dst_vma) to page.
*
* This function handles both MCOPY_ATOMIC_NORMAL and _CONTINUE for both shmem
* and anon, and for both shared and private VMAs.
*/
int mfill_atomic_install_pte(pmd_t *dst_pmd,
struct vm_area_struct *dst_vma,
unsigned long dst_addr, struct page *page,
bool newly_allocated, uffd_flags_t flags)
{
int ret;
struct mm_struct *dst_mm = dst_vma->vm_mm;
pte_t _dst_pte, *dst_pte;
bool writable = dst_vma->vm_flags & VM_WRITE;
bool vm_shared = dst_vma->vm_flags & VM_SHARED;
bool page_in_cache = page_mapping(page);
spinlock_t *ptl;
struct folio *folio;
_dst_pte = mk_pte(page, dst_vma->vm_page_prot);
_dst_pte = pte_mkdirty(_dst_pte);
if (page_in_cache && !vm_shared)
writable = false;
if (writable)
_dst_pte = pte_mkwrite(_dst_pte, dst_vma);
if (flags & MFILL_ATOMIC_WP)
_dst_pte = pte_mkuffd_wp(_dst_pte);
ret = -EAGAIN;
dst_pte = pte_offset_map_lock(dst_mm, dst_pmd, dst_addr, &ptl);
if (!dst_pte)
goto out;
if (mfill_file_over_size(dst_vma, dst_addr)) {
ret = -EFAULT;
goto out_unlock;
}
ret = -EEXIST;
/*
* We allow to overwrite a pte marker: consider when both MISSING|WP
* registered, we firstly wr-protect a none pte which has no page cache
* page backing it, then access the page.
*/
if (!pte_none_mostly(ptep_get(dst_pte)))
goto out_unlock;
folio = page_folio(page);
if (page_in_cache) {
/* Usually, cache pages are already added to LRU */
if (newly_allocated)
folio_add_lru(folio);
page_add_file_rmap(page, dst_vma, false);
} else {
page_add_new_anon_rmap(page, dst_vma, dst_addr);
folio_add_lru_vma(folio, dst_vma);
}
/*
* Must happen after rmap, as mm_counter() checks mapping (via
* PageAnon()), which is set by __page_set_anon_rmap().
*/
inc_mm_counter(dst_mm, mm_counter(page));
set_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte);
/* No need to invalidate - it was non-present before */
update_mmu_cache(dst_vma, dst_addr, dst_pte);
ret = 0;
out_unlock:
pte_unmap_unlock(dst_pte, ptl);
out:
return ret;
}
static int mfill_atomic_pte_copy(pmd_t *dst_pmd,
struct vm_area_struct *dst_vma,
unsigned long dst_addr,
unsigned long src_addr,
uffd_flags_t flags,
struct folio **foliop)
{
void *kaddr;
int ret;
struct folio *folio;
if (!*foliop) {
ret = -ENOMEM;
folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0, dst_vma,
dst_addr, false);
if (!folio)
goto out;
kaddr = kmap_local_folio(folio, 0);
/*
* The read mmap_lock is held here. Despite the
* mmap_lock being read recursive a deadlock is still
* possible if a writer has taken a lock. For example:
*
* process A thread 1 takes read lock on own mmap_lock
* process A thread 2 calls mmap, blocks taking write lock
* process B thread 1 takes page fault, read lock on own mmap lock
* process B thread 2 calls mmap, blocks taking write lock
* process A thread 1 blocks taking read lock on process B
* process B thread 1 blocks taking read lock on process A
*
* Disable page faults to prevent potential deadlock
* and retry the copy outside the mmap_lock.
*/
pagefault_disable();
ret = copy_from_user(kaddr, (const void __user *) src_addr,
PAGE_SIZE);
pagefault_enable();
kunmap_local(kaddr);
/* fallback to copy_from_user outside mmap_lock */
if (unlikely(ret)) {
ret = -ENOENT;
*foliop = folio;
/* don't free the page */
goto out;
}
flush_dcache_folio(folio);
} else {
folio = *foliop;
*foliop = NULL;
}
/*
* The memory barrier inside __folio_mark_uptodate makes sure that
* preceding stores to the page contents become visible before
* the set_pte_at() write.
*/
__folio_mark_uptodate(folio);
ret = -ENOMEM;
if (mem_cgroup_charge(folio, dst_vma->vm_mm, GFP_KERNEL))
goto out_release;
ret = mfill_atomic_install_pte(dst_pmd, dst_vma, dst_addr,
&folio->page, true, flags);
if (ret)
goto out_release;
out:
return ret;
out_release:
folio_put(folio);
goto out;
}
static int mfill_atomic_pte_zeropage(pmd_t *dst_pmd,
struct vm_area_struct *dst_vma,
unsigned long dst_addr)
{
pte_t _dst_pte, *dst_pte;
spinlock_t *ptl;
int ret;
_dst_pte = pte_mkspecial(pfn_pte(my_zero_pfn(dst_addr),
dst_vma->vm_page_prot));
ret = -EAGAIN;
dst_pte = pte_offset_map_lock(dst_vma->vm_mm, dst_pmd, dst_addr, &ptl);
if (!dst_pte)
goto out;
if (mfill_file_over_size(dst_vma, dst_addr)) {
ret = -EFAULT;
goto out_unlock;
}
ret = -EEXIST;
if (!pte_none(ptep_get(dst_pte)))
goto out_unlock;
set_pte_at(dst_vma->vm_mm, dst_addr, dst_pte, _dst_pte);
/* No need to invalidate - it was non-present before */
update_mmu_cache(dst_vma, dst_addr, dst_pte);
ret = 0;
out_unlock:
pte_unmap_unlock(dst_pte, ptl);
out:
return ret;
}
/* Handles UFFDIO_CONTINUE for all shmem VMAs (shared or private). */
static int mfill_atomic_pte_continue(pmd_t *dst_pmd,
struct vm_area_struct *dst_vma,
unsigned long dst_addr,
uffd_flags_t flags)
{
struct inode *inode = file_inode(dst_vma->vm_file);
pgoff_t pgoff = linear_page_index(dst_vma, dst_addr);
struct folio *folio;
struct page *page;
int ret;
ret = shmem_get_folio(inode, pgoff, &folio, SGP_NOALLOC);
/* Our caller expects us to return -EFAULT if we failed to find folio */
if (ret == -ENOENT)
ret = -EFAULT;
if (ret)
goto out;
if (!folio) {
ret = -EFAULT;
goto out;
}
page = folio_file_page(folio, pgoff);
if (PageHWPoison(page)) {
ret = -EIO;
goto out_release;
}
ret = mfill_atomic_install_pte(dst_pmd, dst_vma, dst_addr,
page, false, flags);
if (ret)
goto out_release;
folio_unlock(folio);
ret = 0;
out:
return ret;
out_release:
folio_unlock(folio);
folio_put(folio);
goto out;
}
/* Handles UFFDIO_POISON for all non-hugetlb VMAs. */
static int mfill_atomic_pte_poison(pmd_t *dst_pmd,
struct vm_area_struct *dst_vma,
unsigned long dst_addr,
uffd_flags_t flags)
{
int ret;
struct mm_struct *dst_mm = dst_vma->vm_mm;
pte_t _dst_pte, *dst_pte;
spinlock_t *ptl;
_dst_pte = make_pte_marker(PTE_MARKER_POISONED);
ret = -EAGAIN;
dst_pte = pte_offset_map_lock(dst_mm, dst_pmd, dst_addr, &ptl);
if (!dst_pte)
goto out;
if (mfill_file_over_size(dst_vma, dst_addr)) {
ret = -EFAULT;
goto out_unlock;
}
ret = -EEXIST;
/* Refuse to overwrite any PTE, even a PTE marker (e.g. UFFD WP). */
if (!pte_none(*dst_pte))
goto out_unlock;
set_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte);
/* No need to invalidate - it was non-present before */
update_mmu_cache(dst_vma, dst_addr, dst_pte);
ret = 0;
out_unlock:
pte_unmap_unlock(dst_pte, ptl);
out:
return ret;
}
static pmd_t *mm_alloc_pmd(struct mm_struct *mm, unsigned long address)
{
pgd_t *pgd;
p4d_t *p4d;
pud_t *pud;
pgd = pgd_offset(mm, address);
p4d = p4d_alloc(mm, pgd, address);
if (!p4d)
return NULL;
pud = pud_alloc(mm, p4d, address);
if (!pud)
return NULL;
/*
* Note that we didn't run this because the pmd was
* missing, the *pmd may be already established and in
* turn it may also be a trans_huge_pmd.
*/
return pmd_alloc(mm, pud, address);
}
#ifdef CONFIG_HUGETLB_PAGE
/*
* mfill_atomic processing for HUGETLB vmas. Note that this routine is
* called with mmap_lock held, it will release mmap_lock before returning.
*/
static __always_inline ssize_t mfill_atomic_hugetlb(
struct vm_area_struct *dst_vma,
unsigned long dst_start,
unsigned long src_start,
unsigned long len,
uffd_flags_t flags)
{
struct mm_struct *dst_mm = dst_vma->vm_mm;
int vm_shared = dst_vma->vm_flags & VM_SHARED;
ssize_t err;
pte_t *dst_pte;
unsigned long src_addr, dst_addr;
long copied;
struct folio *folio;
unsigned long vma_hpagesize;
pgoff_t idx;
u32 hash;
struct address_space *mapping;
/*
* There is no default zero huge page for all huge page sizes as
* supported by hugetlb. A PMD_SIZE huge pages may exist as used
* by THP. Since we can not reliably insert a zero page, this
* feature is not supported.
*/
if (uffd_flags_mode_is(flags, MFILL_ATOMIC_ZEROPAGE)) {
mmap_read_unlock(dst_mm);
return -EINVAL;
}
src_addr = src_start;
dst_addr = dst_start;
copied = 0;
folio = NULL;
vma_hpagesize = vma_kernel_pagesize(dst_vma);
/*
* Validate alignment based on huge page size
*/
err = -EINVAL;
if (dst_start & (vma_hpagesize - 1) || len & (vma_hpagesize - 1))
goto out_unlock;
retry:
/*
* On routine entry dst_vma is set. If we had to drop mmap_lock and
* retry, dst_vma will be set to NULL and we must lookup again.
*/
if (!dst_vma) {
err = -ENOENT;
dst_vma = find_dst_vma(dst_mm, dst_start, len);
if (!dst_vma || !is_vm_hugetlb_page(dst_vma))
goto out_unlock;
err = -EINVAL;
if (vma_hpagesize != vma_kernel_pagesize(dst_vma))
goto out_unlock;
vm_shared = dst_vma->vm_flags & VM_SHARED;
}
/*
* If not shared, ensure the dst_vma has a anon_vma.
*/
err = -ENOMEM;
if (!vm_shared) {
if (unlikely(anon_vma_prepare(dst_vma)))
goto out_unlock;
}
while (src_addr < src_start + len) {
BUG_ON(dst_addr >= dst_start + len);
/*
* Serialize via vma_lock and hugetlb_fault_mutex.
* vma_lock ensures the dst_pte remains valid even
* in the case of shared pmds. fault mutex prevents
* races with other faulting threads.
*/
idx = linear_page_index(dst_vma, dst_addr);
mapping = dst_vma->vm_file->f_mapping;
hash = hugetlb_fault_mutex_hash(mapping, idx);
mutex_lock(&hugetlb_fault_mutex_table[hash]);
hugetlb_vma_lock_read(dst_vma);
err = -ENOMEM;
dst_pte = huge_pte_alloc(dst_mm, dst_vma, dst_addr, vma_hpagesize);
if (!dst_pte) {
hugetlb_vma_unlock_read(dst_vma);
mutex_unlock(&hugetlb_fault_mutex_table[hash]);
goto out_unlock;
}
if (!uffd_flags_mode_is(flags, MFILL_ATOMIC_CONTINUE) &&
!huge_pte_none_mostly(huge_ptep_get(dst_pte))) {
err = -EEXIST;
hugetlb_vma_unlock_read(dst_vma);
mutex_unlock(&hugetlb_fault_mutex_table[hash]);
goto out_unlock;
}
err = hugetlb_mfill_atomic_pte(dst_pte, dst_vma, dst_addr,
src_addr, flags, &folio);
hugetlb_vma_unlock_read(dst_vma);
mutex_unlock(&hugetlb_fault_mutex_table[hash]);
cond_resched();
if (unlikely(err == -ENOENT)) {
mmap_read_unlock(dst_mm);
BUG_ON(!folio);
err = copy_folio_from_user(folio,
(const void __user *)src_addr, true);
if (unlikely(err)) {
err = -EFAULT;
goto out;
}
mmap_read_lock(dst_mm);
dst_vma = NULL;
goto retry;
} else
BUG_ON(folio);
if (!err) {
dst_addr += vma_hpagesize;
src_addr += vma_hpagesize;
copied += vma_hpagesize;
if (fatal_signal_pending(current))
err = -EINTR;
}
if (err)
break;
}
out_unlock:
mmap_read_unlock(dst_mm);
out:
if (folio)
folio_put(folio);
BUG_ON(copied < 0);
BUG_ON(err > 0);
BUG_ON(!copied && !err);
return copied ? copied : err;
}
#else /* !CONFIG_HUGETLB_PAGE */
/* fail at build time if gcc attempts to use this */
extern ssize_t mfill_atomic_hugetlb(struct vm_area_struct *dst_vma,
unsigned long dst_start,
unsigned long src_start,
unsigned long len,
uffd_flags_t flags);
#endif /* CONFIG_HUGETLB_PAGE */
static __always_inline ssize_t mfill_atomic_pte(pmd_t *dst_pmd,
struct vm_area_struct *dst_vma,
unsigned long dst_addr,
unsigned long src_addr,
uffd_flags_t flags,
struct folio **foliop)
{
ssize_t err;
if (uffd_flags_mode_is(flags, MFILL_ATOMIC_CONTINUE)) {
return mfill_atomic_pte_continue(dst_pmd, dst_vma,
dst_addr, flags);
} else if (uffd_flags_mode_is(flags, MFILL_ATOMIC_POISON)) {
return mfill_atomic_pte_poison(dst_pmd, dst_vma,
dst_addr, flags);
}
/*
* The normal page fault path for a shmem will invoke the
* fault, fill the hole in the file and COW it right away. The
* result generates plain anonymous memory. So when we are
* asked to fill an hole in a MAP_PRIVATE shmem mapping, we'll
* generate anonymous memory directly without actually filling
* the hole. For the MAP_PRIVATE case the robustness check
* only happens in the pagetable (to verify it's still none)
* and not in the radix tree.
*/
if (!(dst_vma->vm_flags & VM_SHARED)) {
if (uffd_flags_mode_is(flags, MFILL_ATOMIC_COPY))
err = mfill_atomic_pte_copy(dst_pmd, dst_vma,
dst_addr, src_addr,
flags, foliop);
else
err = mfill_atomic_pte_zeropage(dst_pmd,
dst_vma, dst_addr);
} else {
err = shmem_mfill_atomic_pte(dst_pmd, dst_vma,
dst_addr, src_addr,
flags, foliop);
}
return err;
}
static __always_inline ssize_t mfill_atomic(struct mm_struct *dst_mm,
unsigned long dst_start,
unsigned long src_start,
unsigned long len,
atomic_t *mmap_changing,
uffd_flags_t flags)
{
struct vm_area_struct *dst_vma;
ssize_t err;
pmd_t *dst_pmd;
unsigned long src_addr, dst_addr;
long copied;
struct folio *folio;
/*
* Sanitize the command parameters:
*/
BUG_ON(dst_start & ~PAGE_MASK);
BUG_ON(len & ~PAGE_MASK);
/* Does the address range wrap, or is the span zero-sized? */
BUG_ON(src_start + len <= src_start);
BUG_ON(dst_start + len <= dst_start);
src_addr = src_start;
dst_addr = dst_start;
copied = 0;
folio = NULL;
retry:
mmap_read_lock(dst_mm);
/*
* If memory mappings are changing because of non-cooperative
* operation (e.g. mremap) running in parallel, bail out and
* request the user to retry later
*/
err = -EAGAIN;
if (mmap_changing && atomic_read(mmap_changing))
goto out_unlock;
/*
* Make sure the vma is not shared, that the dst range is
* both valid and fully within a single existing vma.
*/
err = -ENOENT;
dst_vma = find_dst_vma(dst_mm, dst_start, len);
if (!dst_vma)
goto out_unlock;
err = -EINVAL;
/*
* shmem_zero_setup is invoked in mmap for MAP_ANONYMOUS|MAP_SHARED but
* it will overwrite vm_ops, so vma_is_anonymous must return false.
*/
if (WARN_ON_ONCE(vma_is_anonymous(dst_vma) &&
dst_vma->vm_flags & VM_SHARED))
goto out_unlock;
/*
* validate 'mode' now that we know the dst_vma: don't allow
* a wrprotect copy if the userfaultfd didn't register as WP.
*/
if ((flags & MFILL_ATOMIC_WP) && !(dst_vma->vm_flags & VM_UFFD_WP))
goto out_unlock;
/*
* If this is a HUGETLB vma, pass off to appropriate routine
*/
if (is_vm_hugetlb_page(dst_vma))
return mfill_atomic_hugetlb(dst_vma, dst_start,
src_start, len, flags);
if (!vma_is_anonymous(dst_vma) && !vma_is_shmem(dst_vma))
goto out_unlock;
if (!vma_is_shmem(dst_vma) &&
uffd_flags_mode_is(flags, MFILL_ATOMIC_CONTINUE))
goto out_unlock;
/*
* Ensure the dst_vma has a anon_vma or this page
* would get a NULL anon_vma when moved in the
* dst_vma.
*/
err = -ENOMEM;
if (!(dst_vma->vm_flags & VM_SHARED) &&
unlikely(anon_vma_prepare(dst_vma)))
goto out_unlock;
while (src_addr < src_start + len) {
pmd_t dst_pmdval;
BUG_ON(dst_addr >= dst_start + len);
dst_pmd = mm_alloc_pmd(dst_mm, dst_addr);
if (unlikely(!dst_pmd)) {
err = -ENOMEM;
break;
}
dst_pmdval = pmdp_get_lockless(dst_pmd);
/*
* If the dst_pmd is mapped as THP don't
* override it and just be strict.
*/
if (unlikely(pmd_trans_huge(dst_pmdval))) {
err = -EEXIST;
break;
}
if (unlikely(pmd_none(dst_pmdval)) &&
unlikely(__pte_alloc(dst_mm, dst_pmd))) {
err = -ENOMEM;
break;
}
/* If an huge pmd materialized from under us fail */
if (unlikely(pmd_trans_huge(*dst_pmd))) {
err = -EFAULT;
break;
}
BUG_ON(pmd_none(*dst_pmd));
BUG_ON(pmd_trans_huge(*dst_pmd));
err = mfill_atomic_pte(dst_pmd, dst_vma, dst_addr,
src_addr, flags, &folio);
cond_resched();
if (unlikely(err == -ENOENT)) {
void *kaddr;
mmap_read_unlock(dst_mm);
BUG_ON(!folio);
kaddr = kmap_local_folio(folio, 0);
err = copy_from_user(kaddr,
(const void __user *) src_addr,
PAGE_SIZE);
kunmap_local(kaddr);
if (unlikely(err)) {
err = -EFAULT;
goto out;
}
flush_dcache_folio(folio);
goto retry;
} else
BUG_ON(folio);
if (!err) {
dst_addr += PAGE_SIZE;
src_addr += PAGE_SIZE;
copied += PAGE_SIZE;
if (fatal_signal_pending(current))
err = -EINTR;
}
if (err)
break;
}
out_unlock:
mmap_read_unlock(dst_mm);
out:
if (folio)
folio_put(folio);
BUG_ON(copied < 0);
BUG_ON(err > 0);
BUG_ON(!copied && !err);
return copied ? copied : err;
}
ssize_t mfill_atomic_copy(struct mm_struct *dst_mm, unsigned long dst_start,
unsigned long src_start, unsigned long len,
atomic_t *mmap_changing, uffd_flags_t flags)
{
return mfill_atomic(dst_mm, dst_start, src_start, len, mmap_changing,
uffd_flags_set_mode(flags, MFILL_ATOMIC_COPY));
}
ssize_t mfill_atomic_zeropage(struct mm_struct *dst_mm, unsigned long start,
unsigned long len, atomic_t *mmap_changing)
{
return mfill_atomic(dst_mm, start, 0, len, mmap_changing,
uffd_flags_set_mode(0, MFILL_ATOMIC_ZEROPAGE));
}
ssize_t mfill_atomic_continue(struct mm_struct *dst_mm, unsigned long start,
unsigned long len, atomic_t *mmap_changing,
uffd_flags_t flags)
{
return mfill_atomic(dst_mm, start, 0, len, mmap_changing,
uffd_flags_set_mode(flags, MFILL_ATOMIC_CONTINUE));
}
ssize_t mfill_atomic_poison(struct mm_struct *dst_mm, unsigned long start,
unsigned long len, atomic_t *mmap_changing,
uffd_flags_t flags)
{
return mfill_atomic(dst_mm, start, 0, len, mmap_changing,
uffd_flags_set_mode(flags, MFILL_ATOMIC_POISON));
}
long uffd_wp_range(struct vm_area_struct *dst_vma,
unsigned long start, unsigned long len, bool enable_wp)
{
unsigned int mm_cp_flags;
struct mmu_gather tlb;
long ret;
VM_WARN_ONCE(start < dst_vma->vm_start || start + len > dst_vma->vm_end,
"The address range exceeds VMA boundary.\n");
if (enable_wp)
mm_cp_flags = MM_CP_UFFD_WP;
else
mm_cp_flags = MM_CP_UFFD_WP_RESOLVE;
/*
* vma->vm_page_prot already reflects that uffd-wp is enabled for this
* VMA (see userfaultfd_set_vm_flags()) and that all PTEs are supposed
* to be write-protected as default whenever protection changes.
* Try upgrading write permissions manually.
*/
if (!enable_wp && vma_wants_manual_pte_write_upgrade(dst_vma))
mm_cp_flags |= MM_CP_TRY_CHANGE_WRITABLE;
tlb_gather_mmu(&tlb, dst_vma->vm_mm);
ret = change_protection(&tlb, dst_vma, start, start + len, mm_cp_flags);
tlb_finish_mmu(&tlb);
return ret;
}
int mwriteprotect_range(struct mm_struct *dst_mm, unsigned long start,
unsigned long len, bool enable_wp,
atomic_t *mmap_changing)
{
unsigned long end = start + len;
unsigned long _start, _end;
struct vm_area_struct *dst_vma;
unsigned long page_mask;
long err;
VMA_ITERATOR(vmi, dst_mm, start);
/*
* Sanitize the command parameters:
*/
BUG_ON(start & ~PAGE_MASK);
BUG_ON(len & ~PAGE_MASK);
/* Does the address range wrap, or is the span zero-sized? */
BUG_ON(start + len <= start);
mmap_read_lock(dst_mm);
/*
* If memory mappings are changing because of non-cooperative
* operation (e.g. mremap) running in parallel, bail out and
* request the user to retry later
*/
err = -EAGAIN;
if (mmap_changing && atomic_read(mmap_changing))
goto out_unlock;
err = -ENOENT;
for_each_vma_range(vmi, dst_vma, end) {
if (!userfaultfd_wp(dst_vma)) {
err = -ENOENT;
break;
}
if (is_vm_hugetlb_page(dst_vma)) {
err = -EINVAL;
page_mask = vma_kernel_pagesize(dst_vma) - 1;
if ((start & page_mask) || (len & page_mask))
break;
}
_start = max(dst_vma->vm_start, start);
_end = min(dst_vma->vm_end, end);
err = uffd_wp_range(dst_vma, _start, _end - _start, enable_wp);
/* Return 0 on success, <0 on failures */
if (err < 0)
break;
err = 0;
}
out_unlock:
mmap_read_unlock(dst_mm);
return err;
}
| linux-master | mm/userfaultfd.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Lockless hierarchical page accounting & limiting
*
* Copyright (C) 2014 Red Hat, Inc., Johannes Weiner
*/
#include <linux/page_counter.h>
#include <linux/atomic.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/sched.h>
#include <linux/bug.h>
#include <asm/page.h>
static void propagate_protected_usage(struct page_counter *c,
unsigned long usage)
{
unsigned long protected, old_protected;
long delta;
if (!c->parent)
return;
protected = min(usage, READ_ONCE(c->min));
old_protected = atomic_long_read(&c->min_usage);
if (protected != old_protected) {
old_protected = atomic_long_xchg(&c->min_usage, protected);
delta = protected - old_protected;
if (delta)
atomic_long_add(delta, &c->parent->children_min_usage);
}
protected = min(usage, READ_ONCE(c->low));
old_protected = atomic_long_read(&c->low_usage);
if (protected != old_protected) {
old_protected = atomic_long_xchg(&c->low_usage, protected);
delta = protected - old_protected;
if (delta)
atomic_long_add(delta, &c->parent->children_low_usage);
}
}
/**
* page_counter_cancel - take pages out of the local counter
* @counter: counter
* @nr_pages: number of pages to cancel
*/
void page_counter_cancel(struct page_counter *counter, unsigned long nr_pages)
{
long new;
new = atomic_long_sub_return(nr_pages, &counter->usage);
/* More uncharges than charges? */
if (WARN_ONCE(new < 0, "page_counter underflow: %ld nr_pages=%lu\n",
new, nr_pages)) {
new = 0;
atomic_long_set(&counter->usage, new);
}
propagate_protected_usage(counter, new);
}
/**
* page_counter_charge - hierarchically charge pages
* @counter: counter
* @nr_pages: number of pages to charge
*
* NOTE: This does not consider any configured counter limits.
*/
void page_counter_charge(struct page_counter *counter, unsigned long nr_pages)
{
struct page_counter *c;
for (c = counter; c; c = c->parent) {
long new;
new = atomic_long_add_return(nr_pages, &c->usage);
propagate_protected_usage(c, new);
/*
* This is indeed racy, but we can live with some
* inaccuracy in the watermark.
*/
if (new > READ_ONCE(c->watermark))
WRITE_ONCE(c->watermark, new);
}
}
/**
* page_counter_try_charge - try to hierarchically charge pages
* @counter: counter
* @nr_pages: number of pages to charge
* @fail: points first counter to hit its limit, if any
*
* Returns %true on success, or %false and @fail if the counter or one
* of its ancestors has hit its configured limit.
*/
bool page_counter_try_charge(struct page_counter *counter,
unsigned long nr_pages,
struct page_counter **fail)
{
struct page_counter *c;
for (c = counter; c; c = c->parent) {
long new;
/*
* Charge speculatively to avoid an expensive CAS. If
* a bigger charge fails, it might falsely lock out a
* racing smaller charge and send it into reclaim
* early, but the error is limited to the difference
* between the two sizes, which is less than 2M/4M in
* case of a THP locking out a regular page charge.
*
* The atomic_long_add_return() implies a full memory
* barrier between incrementing the count and reading
* the limit. When racing with page_counter_set_max(),
* we either see the new limit or the setter sees the
* counter has changed and retries.
*/
new = atomic_long_add_return(nr_pages, &c->usage);
if (new > c->max) {
atomic_long_sub(nr_pages, &c->usage);
/*
* This is racy, but we can live with some
* inaccuracy in the failcnt which is only used
* to report stats.
*/
data_race(c->failcnt++);
*fail = c;
goto failed;
}
propagate_protected_usage(c, new);
/*
* Just like with failcnt, we can live with some
* inaccuracy in the watermark.
*/
if (new > READ_ONCE(c->watermark))
WRITE_ONCE(c->watermark, new);
}
return true;
failed:
for (c = counter; c != *fail; c = c->parent)
page_counter_cancel(c, nr_pages);
return false;
}
/**
* page_counter_uncharge - hierarchically uncharge pages
* @counter: counter
* @nr_pages: number of pages to uncharge
*/
void page_counter_uncharge(struct page_counter *counter, unsigned long nr_pages)
{
struct page_counter *c;
for (c = counter; c; c = c->parent)
page_counter_cancel(c, nr_pages);
}
/**
* page_counter_set_max - set the maximum number of pages allowed
* @counter: counter
* @nr_pages: limit to set
*
* Returns 0 on success, -EBUSY if the current number of pages on the
* counter already exceeds the specified limit.
*
* The caller must serialize invocations on the same counter.
*/
int page_counter_set_max(struct page_counter *counter, unsigned long nr_pages)
{
for (;;) {
unsigned long old;
long usage;
/*
* Update the limit while making sure that it's not
* below the concurrently-changing counter value.
*
* The xchg implies two full memory barriers before
* and after, so the read-swap-read is ordered and
* ensures coherency with page_counter_try_charge():
* that function modifies the count before checking
* the limit, so if it sees the old limit, we see the
* modified counter and retry.
*/
usage = page_counter_read(counter);
if (usage > nr_pages)
return -EBUSY;
old = xchg(&counter->max, nr_pages);
if (page_counter_read(counter) <= usage || nr_pages >= old)
return 0;
counter->max = old;
cond_resched();
}
}
/**
* page_counter_set_min - set the amount of protected memory
* @counter: counter
* @nr_pages: value to set
*
* The caller must serialize invocations on the same counter.
*/
void page_counter_set_min(struct page_counter *counter, unsigned long nr_pages)
{
struct page_counter *c;
WRITE_ONCE(counter->min, nr_pages);
for (c = counter; c; c = c->parent)
propagate_protected_usage(c, atomic_long_read(&c->usage));
}
/**
* page_counter_set_low - set the amount of protected memory
* @counter: counter
* @nr_pages: value to set
*
* The caller must serialize invocations on the same counter.
*/
void page_counter_set_low(struct page_counter *counter, unsigned long nr_pages)
{
struct page_counter *c;
WRITE_ONCE(counter->low, nr_pages);
for (c = counter; c; c = c->parent)
propagate_protected_usage(c, atomic_long_read(&c->usage));
}
/**
* page_counter_memparse - memparse() for page counter limits
* @buf: string to parse
* @max: string meaning maximum possible value
* @nr_pages: returns the result in number of pages
*
* Returns -EINVAL, or 0 and @nr_pages on success. @nr_pages will be
* limited to %PAGE_COUNTER_MAX.
*/
int page_counter_memparse(const char *buf, const char *max,
unsigned long *nr_pages)
{
char *end;
u64 bytes;
if (!strcmp(buf, max)) {
*nr_pages = PAGE_COUNTER_MAX;
return 0;
}
bytes = memparse(buf, &end);
if (*end != '\0')
return -EINVAL;
*nr_pages = min(bytes / PAGE_SIZE, (u64)PAGE_COUNTER_MAX);
return 0;
}
| linux-master | mm/page_counter.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/mmdebug.h>
#include <linux/highmem.h>
#include <linux/poison.h>
#include <linux/ratelimit.h>
#include <linux/kasan.h>
bool _page_poisoning_enabled_early;
EXPORT_SYMBOL(_page_poisoning_enabled_early);
DEFINE_STATIC_KEY_FALSE(_page_poisoning_enabled);
EXPORT_SYMBOL(_page_poisoning_enabled);
static int __init early_page_poison_param(char *buf)
{
return kstrtobool(buf, &_page_poisoning_enabled_early);
}
early_param("page_poison", early_page_poison_param);
static void poison_page(struct page *page)
{
void *addr = kmap_atomic(page);
/* KASAN still think the page is in-use, so skip it. */
kasan_disable_current();
memset(kasan_reset_tag(addr), PAGE_POISON, PAGE_SIZE);
kasan_enable_current();
kunmap_atomic(addr);
}
void __kernel_poison_pages(struct page *page, int n)
{
int i;
for (i = 0; i < n; i++)
poison_page(page + i);
}
static bool single_bit_flip(unsigned char a, unsigned char b)
{
unsigned char error = a ^ b;
return error && !(error & (error - 1));
}
static void check_poison_mem(struct page *page, unsigned char *mem, size_t bytes)
{
static DEFINE_RATELIMIT_STATE(ratelimit, 5 * HZ, 10);
unsigned char *start;
unsigned char *end;
start = memchr_inv(mem, PAGE_POISON, bytes);
if (!start)
return;
for (end = mem + bytes - 1; end > start; end--) {
if (*end != PAGE_POISON)
break;
}
if (!__ratelimit(&ratelimit))
return;
else if (start == end && single_bit_flip(*start, PAGE_POISON))
pr_err("pagealloc: single bit error\n");
else
pr_err("pagealloc: memory corruption\n");
print_hex_dump(KERN_ERR, "", DUMP_PREFIX_ADDRESS, 16, 1, start,
end - start + 1, 1);
dump_stack();
dump_page(page, "pagealloc: corrupted page details");
}
static void unpoison_page(struct page *page)
{
void *addr;
addr = kmap_atomic(page);
kasan_disable_current();
/*
* Page poisoning when enabled poisons each and every page
* that is freed to buddy. Thus no extra check is done to
* see if a page was poisoned.
*/
check_poison_mem(page, kasan_reset_tag(addr), PAGE_SIZE);
kasan_enable_current();
kunmap_atomic(addr);
}
void __kernel_unpoison_pages(struct page *page, int n)
{
int i;
for (i = 0; i < n; i++)
unpoison_page(page + i);
}
#ifndef CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC
void __kernel_map_pages(struct page *page, int numpages, int enable)
{
/* This function does nothing, all work is done via poison pages */
}
#endif
| linux-master | mm/page_poison.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* mm/percpu-debug.c
*
* Copyright (C) 2017 Facebook Inc.
* Copyright (C) 2017 Dennis Zhou <[email protected]>
*
* Prints statistics about the percpu allocator and backing chunks.
*/
#include <linux/debugfs.h>
#include <linux/list.h>
#include <linux/percpu.h>
#include <linux/seq_file.h>
#include <linux/sort.h>
#include <linux/vmalloc.h>
#include "percpu-internal.h"
#define P(X, Y) \
seq_printf(m, " %-20s: %12lld\n", X, (long long int)Y)
struct percpu_stats pcpu_stats;
struct pcpu_alloc_info pcpu_stats_ai;
static int cmpint(const void *a, const void *b)
{
return *(int *)a - *(int *)b;
}
/*
* Iterates over all chunks to find the max nr_alloc entries.
*/
static int find_max_nr_alloc(void)
{
struct pcpu_chunk *chunk;
int slot, max_nr_alloc;
max_nr_alloc = 0;
for (slot = 0; slot < pcpu_nr_slots; slot++)
list_for_each_entry(chunk, &pcpu_chunk_lists[slot], list)
max_nr_alloc = max(max_nr_alloc, chunk->nr_alloc);
return max_nr_alloc;
}
/*
* Prints out chunk state. Fragmentation is considered between
* the beginning of the chunk to the last allocation.
*
* All statistics are in bytes unless stated otherwise.
*/
static void chunk_map_stats(struct seq_file *m, struct pcpu_chunk *chunk,
int *buffer)
{
struct pcpu_block_md *chunk_md = &chunk->chunk_md;
int i, last_alloc, as_len, start, end;
int *alloc_sizes, *p;
/* statistics */
int sum_frag = 0, max_frag = 0;
int cur_min_alloc = 0, cur_med_alloc = 0, cur_max_alloc = 0;
alloc_sizes = buffer;
/*
* find_last_bit returns the start value if nothing found.
* Therefore, we must determine if it is a failure of find_last_bit
* and set the appropriate value.
*/
last_alloc = find_last_bit(chunk->alloc_map,
pcpu_chunk_map_bits(chunk) -
chunk->end_offset / PCPU_MIN_ALLOC_SIZE - 1);
last_alloc = test_bit(last_alloc, chunk->alloc_map) ?
last_alloc + 1 : 0;
as_len = 0;
start = chunk->start_offset / PCPU_MIN_ALLOC_SIZE;
/*
* If a bit is set in the allocation map, the bound_map identifies
* where the allocation ends. If the allocation is not set, the
* bound_map does not identify free areas as it is only kept accurate
* on allocation, not free.
*
* Positive values are allocations and negative values are free
* fragments.
*/
while (start < last_alloc) {
if (test_bit(start, chunk->alloc_map)) {
end = find_next_bit(chunk->bound_map, last_alloc,
start + 1);
alloc_sizes[as_len] = 1;
} else {
end = find_next_bit(chunk->alloc_map, last_alloc,
start + 1);
alloc_sizes[as_len] = -1;
}
alloc_sizes[as_len++] *= (end - start) * PCPU_MIN_ALLOC_SIZE;
start = end;
}
/*
* The negative values are free fragments and thus sorting gives the
* free fragments at the beginning in largest first order.
*/
if (as_len > 0) {
sort(alloc_sizes, as_len, sizeof(int), cmpint, NULL);
/* iterate through the unallocated fragments */
for (i = 0, p = alloc_sizes; *p < 0 && i < as_len; i++, p++) {
sum_frag -= *p;
max_frag = max(max_frag, -1 * (*p));
}
cur_min_alloc = alloc_sizes[i];
cur_med_alloc = alloc_sizes[(i + as_len - 1) / 2];
cur_max_alloc = alloc_sizes[as_len - 1];
}
P("nr_alloc", chunk->nr_alloc);
P("max_alloc_size", chunk->max_alloc_size);
P("empty_pop_pages", chunk->nr_empty_pop_pages);
P("first_bit", chunk_md->first_free);
P("free_bytes", chunk->free_bytes);
P("contig_bytes", chunk_md->contig_hint * PCPU_MIN_ALLOC_SIZE);
P("sum_frag", sum_frag);
P("max_frag", max_frag);
P("cur_min_alloc", cur_min_alloc);
P("cur_med_alloc", cur_med_alloc);
P("cur_max_alloc", cur_max_alloc);
seq_putc(m, '\n');
}
static int percpu_stats_show(struct seq_file *m, void *v)
{
struct pcpu_chunk *chunk;
int slot, max_nr_alloc;
int *buffer;
alloc_buffer:
spin_lock_irq(&pcpu_lock);
max_nr_alloc = find_max_nr_alloc();
spin_unlock_irq(&pcpu_lock);
/* there can be at most this many free and allocated fragments */
buffer = vmalloc_array(2 * max_nr_alloc + 1, sizeof(int));
if (!buffer)
return -ENOMEM;
spin_lock_irq(&pcpu_lock);
/* if the buffer allocated earlier is too small */
if (max_nr_alloc < find_max_nr_alloc()) {
spin_unlock_irq(&pcpu_lock);
vfree(buffer);
goto alloc_buffer;
}
#define PL(X) \
seq_printf(m, " %-20s: %12lld\n", #X, (long long int)pcpu_stats_ai.X)
seq_printf(m,
"Percpu Memory Statistics\n"
"Allocation Info:\n"
"----------------------------------------\n");
PL(unit_size);
PL(static_size);
PL(reserved_size);
PL(dyn_size);
PL(atom_size);
PL(alloc_size);
seq_putc(m, '\n');
#undef PL
#define PU(X) \
seq_printf(m, " %-20s: %12llu\n", #X, (unsigned long long)pcpu_stats.X)
seq_printf(m,
"Global Stats:\n"
"----------------------------------------\n");
PU(nr_alloc);
PU(nr_dealloc);
PU(nr_cur_alloc);
PU(nr_max_alloc);
PU(nr_chunks);
PU(nr_max_chunks);
PU(min_alloc_size);
PU(max_alloc_size);
P("empty_pop_pages", pcpu_nr_empty_pop_pages);
seq_putc(m, '\n');
#undef PU
seq_printf(m,
"Per Chunk Stats:\n"
"----------------------------------------\n");
if (pcpu_reserved_chunk) {
seq_puts(m, "Chunk: <- Reserved Chunk\n");
chunk_map_stats(m, pcpu_reserved_chunk, buffer);
}
for (slot = 0; slot < pcpu_nr_slots; slot++) {
list_for_each_entry(chunk, &pcpu_chunk_lists[slot], list) {
if (chunk == pcpu_first_chunk)
seq_puts(m, "Chunk: <- First Chunk\n");
else if (slot == pcpu_to_depopulate_slot)
seq_puts(m, "Chunk (to_depopulate)\n");
else if (slot == pcpu_sidelined_slot)
seq_puts(m, "Chunk (sidelined):\n");
else
seq_puts(m, "Chunk:\n");
chunk_map_stats(m, chunk, buffer);
}
}
spin_unlock_irq(&pcpu_lock);
vfree(buffer);
return 0;
}
DEFINE_SHOW_ATTRIBUTE(percpu_stats);
static int __init init_percpu_stats_debugfs(void)
{
debugfs_create_file("percpu_stats", 0444, NULL, NULL,
&percpu_stats_fops);
return 0;
}
late_initcall(init_percpu_stats_debugfs);
| linux-master | mm/percpu-stats.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/mm_types.h>
#include <linux/tracepoint.h>
#define CREATE_TRACE_POINTS
#include <trace/events/page_ref.h>
void __page_ref_set(struct page *page, int v)
{
trace_page_ref_set(page, v);
}
EXPORT_SYMBOL(__page_ref_set);
EXPORT_TRACEPOINT_SYMBOL(page_ref_set);
void __page_ref_mod(struct page *page, int v)
{
trace_page_ref_mod(page, v);
}
EXPORT_SYMBOL(__page_ref_mod);
EXPORT_TRACEPOINT_SYMBOL(page_ref_mod);
void __page_ref_mod_and_test(struct page *page, int v, int ret)
{
trace_page_ref_mod_and_test(page, v, ret);
}
EXPORT_SYMBOL(__page_ref_mod_and_test);
EXPORT_TRACEPOINT_SYMBOL(page_ref_mod_and_test);
void __page_ref_mod_and_return(struct page *page, int v, int ret)
{
trace_page_ref_mod_and_return(page, v, ret);
}
EXPORT_SYMBOL(__page_ref_mod_and_return);
EXPORT_TRACEPOINT_SYMBOL(page_ref_mod_and_return);
void __page_ref_mod_unless(struct page *page, int v, int u)
{
trace_page_ref_mod_unless(page, v, u);
}
EXPORT_SYMBOL(__page_ref_mod_unless);
EXPORT_TRACEPOINT_SYMBOL(page_ref_mod_unless);
void __page_ref_freeze(struct page *page, int v, int ret)
{
trace_page_ref_freeze(page, v, ret);
}
EXPORT_SYMBOL(__page_ref_freeze);
EXPORT_TRACEPOINT_SYMBOL(page_ref_freeze);
void __page_ref_unfreeze(struct page *page, int v)
{
trace_page_ref_unfreeze(page, v);
}
EXPORT_SYMBOL(__page_ref_unfreeze);
EXPORT_TRACEPOINT_SYMBOL(page_ref_unfreeze);
| linux-master | mm/debug_page_ref.c |
/*
* memfd_create system call and file sealing support
*
* Code was originally included in shmem.c, and broken out to facilitate
* use by hugetlbfs as well as tmpfs.
*
* This file is released under the GPL.
*/
#include <linux/fs.h>
#include <linux/vfs.h>
#include <linux/pagemap.h>
#include <linux/file.h>
#include <linux/mm.h>
#include <linux/sched/signal.h>
#include <linux/khugepaged.h>
#include <linux/syscalls.h>
#include <linux/hugetlb.h>
#include <linux/shmem_fs.h>
#include <linux/memfd.h>
#include <linux/pid_namespace.h>
#include <uapi/linux/memfd.h>
/*
* We need a tag: a new tag would expand every xa_node by 8 bytes,
* so reuse a tag which we firmly believe is never set or cleared on tmpfs
* or hugetlbfs because they are memory only filesystems.
*/
#define MEMFD_TAG_PINNED PAGECACHE_TAG_TOWRITE
#define LAST_SCAN 4 /* about 150ms max */
static void memfd_tag_pins(struct xa_state *xas)
{
struct page *page;
int latency = 0;
int cache_count;
lru_add_drain();
xas_lock_irq(xas);
xas_for_each(xas, page, ULONG_MAX) {
cache_count = 1;
if (!xa_is_value(page) &&
PageTransHuge(page) && !PageHuge(page))
cache_count = HPAGE_PMD_NR;
if (!xa_is_value(page) &&
page_count(page) - total_mapcount(page) != cache_count)
xas_set_mark(xas, MEMFD_TAG_PINNED);
if (cache_count != 1)
xas_set(xas, page->index + cache_count);
latency += cache_count;
if (latency < XA_CHECK_SCHED)
continue;
latency = 0;
xas_pause(xas);
xas_unlock_irq(xas);
cond_resched();
xas_lock_irq(xas);
}
xas_unlock_irq(xas);
}
/*
* Setting SEAL_WRITE requires us to verify there's no pending writer. However,
* via get_user_pages(), drivers might have some pending I/O without any active
* user-space mappings (eg., direct-IO, AIO). Therefore, we look at all pages
* and see whether it has an elevated ref-count. If so, we tag them and wait for
* them to be dropped.
* The caller must guarantee that no new user will acquire writable references
* to those pages to avoid races.
*/
static int memfd_wait_for_pins(struct address_space *mapping)
{
XA_STATE(xas, &mapping->i_pages, 0);
struct page *page;
int error, scan;
memfd_tag_pins(&xas);
error = 0;
for (scan = 0; scan <= LAST_SCAN; scan++) {
int latency = 0;
int cache_count;
if (!xas_marked(&xas, MEMFD_TAG_PINNED))
break;
if (!scan)
lru_add_drain_all();
else if (schedule_timeout_killable((HZ << scan) / 200))
scan = LAST_SCAN;
xas_set(&xas, 0);
xas_lock_irq(&xas);
xas_for_each_marked(&xas, page, ULONG_MAX, MEMFD_TAG_PINNED) {
bool clear = true;
cache_count = 1;
if (!xa_is_value(page) &&
PageTransHuge(page) && !PageHuge(page))
cache_count = HPAGE_PMD_NR;
if (!xa_is_value(page) && cache_count !=
page_count(page) - total_mapcount(page)) {
/*
* On the last scan, we clean up all those tags
* we inserted; but make a note that we still
* found pages pinned.
*/
if (scan == LAST_SCAN)
error = -EBUSY;
else
clear = false;
}
if (clear)
xas_clear_mark(&xas, MEMFD_TAG_PINNED);
latency += cache_count;
if (latency < XA_CHECK_SCHED)
continue;
latency = 0;
xas_pause(&xas);
xas_unlock_irq(&xas);
cond_resched();
xas_lock_irq(&xas);
}
xas_unlock_irq(&xas);
}
return error;
}
static unsigned int *memfd_file_seals_ptr(struct file *file)
{
if (shmem_file(file))
return &SHMEM_I(file_inode(file))->seals;
#ifdef CONFIG_HUGETLBFS
if (is_file_hugepages(file))
return &HUGETLBFS_I(file_inode(file))->seals;
#endif
return NULL;
}
#define F_ALL_SEALS (F_SEAL_SEAL | \
F_SEAL_EXEC | \
F_SEAL_SHRINK | \
F_SEAL_GROW | \
F_SEAL_WRITE | \
F_SEAL_FUTURE_WRITE)
static int memfd_add_seals(struct file *file, unsigned int seals)
{
struct inode *inode = file_inode(file);
unsigned int *file_seals;
int error;
/*
* SEALING
* Sealing allows multiple parties to share a tmpfs or hugetlbfs file
* but restrict access to a specific subset of file operations. Seals
* can only be added, but never removed. This way, mutually untrusted
* parties can share common memory regions with a well-defined policy.
* A malicious peer can thus never perform unwanted operations on a
* shared object.
*
* Seals are only supported on special tmpfs or hugetlbfs files and
* always affect the whole underlying inode. Once a seal is set, it
* may prevent some kinds of access to the file. Currently, the
* following seals are defined:
* SEAL_SEAL: Prevent further seals from being set on this file
* SEAL_SHRINK: Prevent the file from shrinking
* SEAL_GROW: Prevent the file from growing
* SEAL_WRITE: Prevent write access to the file
* SEAL_EXEC: Prevent modification of the exec bits in the file mode
*
* As we don't require any trust relationship between two parties, we
* must prevent seals from being removed. Therefore, sealing a file
* only adds a given set of seals to the file, it never touches
* existing seals. Furthermore, the "setting seals"-operation can be
* sealed itself, which basically prevents any further seal from being
* added.
*
* Semantics of sealing are only defined on volatile files. Only
* anonymous tmpfs and hugetlbfs files support sealing. More
* importantly, seals are never written to disk. Therefore, there's
* no plan to support it on other file types.
*/
if (!(file->f_mode & FMODE_WRITE))
return -EPERM;
if (seals & ~(unsigned int)F_ALL_SEALS)
return -EINVAL;
inode_lock(inode);
file_seals = memfd_file_seals_ptr(file);
if (!file_seals) {
error = -EINVAL;
goto unlock;
}
if (*file_seals & F_SEAL_SEAL) {
error = -EPERM;
goto unlock;
}
if ((seals & F_SEAL_WRITE) && !(*file_seals & F_SEAL_WRITE)) {
error = mapping_deny_writable(file->f_mapping);
if (error)
goto unlock;
error = memfd_wait_for_pins(file->f_mapping);
if (error) {
mapping_allow_writable(file->f_mapping);
goto unlock;
}
}
/*
* SEAL_EXEC implys SEAL_WRITE, making W^X from the start.
*/
if (seals & F_SEAL_EXEC && inode->i_mode & 0111)
seals |= F_SEAL_SHRINK|F_SEAL_GROW|F_SEAL_WRITE|F_SEAL_FUTURE_WRITE;
*file_seals |= seals;
error = 0;
unlock:
inode_unlock(inode);
return error;
}
static int memfd_get_seals(struct file *file)
{
unsigned int *seals = memfd_file_seals_ptr(file);
return seals ? *seals : -EINVAL;
}
long memfd_fcntl(struct file *file, unsigned int cmd, unsigned int arg)
{
long error;
switch (cmd) {
case F_ADD_SEALS:
error = memfd_add_seals(file, arg);
break;
case F_GET_SEALS:
error = memfd_get_seals(file);
break;
default:
error = -EINVAL;
break;
}
return error;
}
#define MFD_NAME_PREFIX "memfd:"
#define MFD_NAME_PREFIX_LEN (sizeof(MFD_NAME_PREFIX) - 1)
#define MFD_NAME_MAX_LEN (NAME_MAX - MFD_NAME_PREFIX_LEN)
#define MFD_ALL_FLAGS (MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_HUGETLB | MFD_NOEXEC_SEAL | MFD_EXEC)
static int check_sysctl_memfd_noexec(unsigned int *flags)
{
#ifdef CONFIG_SYSCTL
struct pid_namespace *ns = task_active_pid_ns(current);
int sysctl = pidns_memfd_noexec_scope(ns);
if (!(*flags & (MFD_EXEC | MFD_NOEXEC_SEAL))) {
if (sysctl >= MEMFD_NOEXEC_SCOPE_NOEXEC_SEAL)
*flags |= MFD_NOEXEC_SEAL;
else
*flags |= MFD_EXEC;
}
if (!(*flags & MFD_NOEXEC_SEAL) && sysctl >= MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED) {
pr_err_ratelimited(
"%s[%d]: memfd_create() requires MFD_NOEXEC_SEAL with vm.memfd_noexec=%d\n",
current->comm, task_pid_nr(current), sysctl);
return -EACCES;
}
#endif
return 0;
}
SYSCALL_DEFINE2(memfd_create,
const char __user *, uname,
unsigned int, flags)
{
unsigned int *file_seals;
struct file *file;
int fd, error;
char *name;
long len;
if (!(flags & MFD_HUGETLB)) {
if (flags & ~(unsigned int)MFD_ALL_FLAGS)
return -EINVAL;
} else {
/* Allow huge page size encoding in flags. */
if (flags & ~(unsigned int)(MFD_ALL_FLAGS |
(MFD_HUGE_MASK << MFD_HUGE_SHIFT)))
return -EINVAL;
}
/* Invalid if both EXEC and NOEXEC_SEAL are set.*/
if ((flags & MFD_EXEC) && (flags & MFD_NOEXEC_SEAL))
return -EINVAL;
if (!(flags & (MFD_EXEC | MFD_NOEXEC_SEAL))) {
pr_warn_once(
"%s[%d]: memfd_create() called without MFD_EXEC or MFD_NOEXEC_SEAL set\n",
current->comm, task_pid_nr(current));
}
error = check_sysctl_memfd_noexec(&flags);
if (error < 0)
return error;
/* length includes terminating zero */
len = strnlen_user(uname, MFD_NAME_MAX_LEN + 1);
if (len <= 0)
return -EFAULT;
if (len > MFD_NAME_MAX_LEN + 1)
return -EINVAL;
name = kmalloc(len + MFD_NAME_PREFIX_LEN, GFP_KERNEL);
if (!name)
return -ENOMEM;
strcpy(name, MFD_NAME_PREFIX);
if (copy_from_user(&name[MFD_NAME_PREFIX_LEN], uname, len)) {
error = -EFAULT;
goto err_name;
}
/* terminating-zero may have changed after strnlen_user() returned */
if (name[len + MFD_NAME_PREFIX_LEN - 1]) {
error = -EFAULT;
goto err_name;
}
fd = get_unused_fd_flags((flags & MFD_CLOEXEC) ? O_CLOEXEC : 0);
if (fd < 0) {
error = fd;
goto err_name;
}
if (flags & MFD_HUGETLB) {
file = hugetlb_file_setup(name, 0, VM_NORESERVE,
HUGETLB_ANONHUGE_INODE,
(flags >> MFD_HUGE_SHIFT) &
MFD_HUGE_MASK);
} else
file = shmem_file_setup(name, 0, VM_NORESERVE);
if (IS_ERR(file)) {
error = PTR_ERR(file);
goto err_fd;
}
file->f_mode |= FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE;
file->f_flags |= O_LARGEFILE;
if (flags & MFD_NOEXEC_SEAL) {
struct inode *inode = file_inode(file);
inode->i_mode &= ~0111;
file_seals = memfd_file_seals_ptr(file);
if (file_seals) {
*file_seals &= ~F_SEAL_SEAL;
*file_seals |= F_SEAL_EXEC;
}
} else if (flags & MFD_ALLOW_SEALING) {
/* MFD_EXEC and MFD_ALLOW_SEALING are set */
file_seals = memfd_file_seals_ptr(file);
if (file_seals)
*file_seals &= ~F_SEAL_SEAL;
}
fd_install(fd, file);
kfree(name);
return fd;
err_fd:
put_unused_fd(fd);
err_name:
kfree(name);
return error;
}
| linux-master | mm/memfd.c |
// SPDX-License-Identifier: GPL-2.0
/*
* High memory handling common code and variables.
*
* (C) 1999 Andrea Arcangeli, SuSE GmbH, [email protected]
* Gerhard Wichert, Siemens AG, [email protected]
*
*
* Redesigned the x86 32-bit VM architecture to deal with
* 64-bit physical space. With current x86 CPUs this
* means up to 64 Gigabytes physical RAM.
*
* Rewrote high memory support to move the page cache into
* high memory. Implemented permanent (schedulable) kmaps
* based on Linus' idea.
*
* Copyright (C) 1999 Ingo Molnar <[email protected]>
*/
#include <linux/mm.h>
#include <linux/export.h>
#include <linux/swap.h>
#include <linux/bio.h>
#include <linux/pagemap.h>
#include <linux/mempool.h>
#include <linux/init.h>
#include <linux/hash.h>
#include <linux/highmem.h>
#include <linux/kgdb.h>
#include <asm/tlbflush.h>
#include <linux/vmalloc.h>
#ifdef CONFIG_KMAP_LOCAL
static inline int kmap_local_calc_idx(int idx)
{
return idx + KM_MAX_IDX * smp_processor_id();
}
#ifndef arch_kmap_local_map_idx
#define arch_kmap_local_map_idx(idx, pfn) kmap_local_calc_idx(idx)
#endif
#endif /* CONFIG_KMAP_LOCAL */
/*
* Virtual_count is not a pure "count".
* 0 means that it is not mapped, and has not been mapped
* since a TLB flush - it is usable.
* 1 means that there are no users, but it has been mapped
* since the last TLB flush - so we can't use it.
* n means that there are (n-1) current users of it.
*/
#ifdef CONFIG_HIGHMEM
/*
* Architecture with aliasing data cache may define the following family of
* helper functions in its asm/highmem.h to control cache color of virtual
* addresses where physical memory pages are mapped by kmap.
*/
#ifndef get_pkmap_color
/*
* Determine color of virtual address where the page should be mapped.
*/
static inline unsigned int get_pkmap_color(struct page *page)
{
return 0;
}
#define get_pkmap_color get_pkmap_color
/*
* Get next index for mapping inside PKMAP region for page with given color.
*/
static inline unsigned int get_next_pkmap_nr(unsigned int color)
{
static unsigned int last_pkmap_nr;
last_pkmap_nr = (last_pkmap_nr + 1) & LAST_PKMAP_MASK;
return last_pkmap_nr;
}
/*
* Determine if page index inside PKMAP region (pkmap_nr) of given color
* has wrapped around PKMAP region end. When this happens an attempt to
* flush all unused PKMAP slots is made.
*/
static inline int no_more_pkmaps(unsigned int pkmap_nr, unsigned int color)
{
return pkmap_nr == 0;
}
/*
* Get the number of PKMAP entries of the given color. If no free slot is
* found after checking that many entries, kmap will sleep waiting for
* someone to call kunmap and free PKMAP slot.
*/
static inline int get_pkmap_entries_count(unsigned int color)
{
return LAST_PKMAP;
}
/*
* Get head of a wait queue for PKMAP entries of the given color.
* Wait queues for different mapping colors should be independent to avoid
* unnecessary wakeups caused by freeing of slots of other colors.
*/
static inline wait_queue_head_t *get_pkmap_wait_queue_head(unsigned int color)
{
static DECLARE_WAIT_QUEUE_HEAD(pkmap_map_wait);
return &pkmap_map_wait;
}
#endif
atomic_long_t _totalhigh_pages __read_mostly;
EXPORT_SYMBOL(_totalhigh_pages);
unsigned int __nr_free_highpages(void)
{
struct zone *zone;
unsigned int pages = 0;
for_each_populated_zone(zone) {
if (is_highmem(zone))
pages += zone_page_state(zone, NR_FREE_PAGES);
}
return pages;
}
static int pkmap_count[LAST_PKMAP];
static __cacheline_aligned_in_smp DEFINE_SPINLOCK(kmap_lock);
pte_t *pkmap_page_table;
/*
* Most architectures have no use for kmap_high_get(), so let's abstract
* the disabling of IRQ out of the locking in that case to save on a
* potential useless overhead.
*/
#ifdef ARCH_NEEDS_KMAP_HIGH_GET
#define lock_kmap() spin_lock_irq(&kmap_lock)
#define unlock_kmap() spin_unlock_irq(&kmap_lock)
#define lock_kmap_any(flags) spin_lock_irqsave(&kmap_lock, flags)
#define unlock_kmap_any(flags) spin_unlock_irqrestore(&kmap_lock, flags)
#else
#define lock_kmap() spin_lock(&kmap_lock)
#define unlock_kmap() spin_unlock(&kmap_lock)
#define lock_kmap_any(flags) \
do { spin_lock(&kmap_lock); (void)(flags); } while (0)
#define unlock_kmap_any(flags) \
do { spin_unlock(&kmap_lock); (void)(flags); } while (0)
#endif
struct page *__kmap_to_page(void *vaddr)
{
unsigned long base = (unsigned long) vaddr & PAGE_MASK;
struct kmap_ctrl *kctrl = ¤t->kmap_ctrl;
unsigned long addr = (unsigned long)vaddr;
int i;
/* kmap() mappings */
if (WARN_ON_ONCE(addr >= PKMAP_ADDR(0) &&
addr < PKMAP_ADDR(LAST_PKMAP)))
return pte_page(ptep_get(&pkmap_page_table[PKMAP_NR(addr)]));
/* kmap_local_page() mappings */
if (WARN_ON_ONCE(base >= __fix_to_virt(FIX_KMAP_END) &&
base < __fix_to_virt(FIX_KMAP_BEGIN))) {
for (i = 0; i < kctrl->idx; i++) {
unsigned long base_addr;
int idx;
idx = arch_kmap_local_map_idx(i, pte_pfn(pteval));
base_addr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
if (base_addr == base)
return pte_page(kctrl->pteval[i]);
}
}
return virt_to_page(vaddr);
}
EXPORT_SYMBOL(__kmap_to_page);
static void flush_all_zero_pkmaps(void)
{
int i;
int need_flush = 0;
flush_cache_kmaps();
for (i = 0; i < LAST_PKMAP; i++) {
struct page *page;
pte_t ptent;
/*
* zero means we don't have anything to do,
* >1 means that it is still in use. Only
* a count of 1 means that it is free but
* needs to be unmapped
*/
if (pkmap_count[i] != 1)
continue;
pkmap_count[i] = 0;
/* sanity check */
ptent = ptep_get(&pkmap_page_table[i]);
BUG_ON(pte_none(ptent));
/*
* Don't need an atomic fetch-and-clear op here;
* no-one has the page mapped, and cannot get at
* its virtual address (and hence PTE) without first
* getting the kmap_lock (which is held here).
* So no dangers, even with speculative execution.
*/
page = pte_page(ptent);
pte_clear(&init_mm, PKMAP_ADDR(i), &pkmap_page_table[i]);
set_page_address(page, NULL);
need_flush = 1;
}
if (need_flush)
flush_tlb_kernel_range(PKMAP_ADDR(0), PKMAP_ADDR(LAST_PKMAP));
}
void __kmap_flush_unused(void)
{
lock_kmap();
flush_all_zero_pkmaps();
unlock_kmap();
}
static inline unsigned long map_new_virtual(struct page *page)
{
unsigned long vaddr;
int count;
unsigned int last_pkmap_nr;
unsigned int color = get_pkmap_color(page);
start:
count = get_pkmap_entries_count(color);
/* Find an empty entry */
for (;;) {
last_pkmap_nr = get_next_pkmap_nr(color);
if (no_more_pkmaps(last_pkmap_nr, color)) {
flush_all_zero_pkmaps();
count = get_pkmap_entries_count(color);
}
if (!pkmap_count[last_pkmap_nr])
break; /* Found a usable entry */
if (--count)
continue;
/*
* Sleep for somebody else to unmap their entries
*/
{
DECLARE_WAITQUEUE(wait, current);
wait_queue_head_t *pkmap_map_wait =
get_pkmap_wait_queue_head(color);
__set_current_state(TASK_UNINTERRUPTIBLE);
add_wait_queue(pkmap_map_wait, &wait);
unlock_kmap();
schedule();
remove_wait_queue(pkmap_map_wait, &wait);
lock_kmap();
/* Somebody else might have mapped it while we slept */
if (page_address(page))
return (unsigned long)page_address(page);
/* Re-start */
goto start;
}
}
vaddr = PKMAP_ADDR(last_pkmap_nr);
set_pte_at(&init_mm, vaddr,
&(pkmap_page_table[last_pkmap_nr]), mk_pte(page, kmap_prot));
pkmap_count[last_pkmap_nr] = 1;
set_page_address(page, (void *)vaddr);
return vaddr;
}
/**
* kmap_high - map a highmem page into memory
* @page: &struct page to map
*
* Returns the page's virtual memory address.
*
* We cannot call this from interrupts, as it may block.
*/
void *kmap_high(struct page *page)
{
unsigned long vaddr;
/*
* For highmem pages, we can't trust "virtual" until
* after we have the lock.
*/
lock_kmap();
vaddr = (unsigned long)page_address(page);
if (!vaddr)
vaddr = map_new_virtual(page);
pkmap_count[PKMAP_NR(vaddr)]++;
BUG_ON(pkmap_count[PKMAP_NR(vaddr)] < 2);
unlock_kmap();
return (void *) vaddr;
}
EXPORT_SYMBOL(kmap_high);
#ifdef ARCH_NEEDS_KMAP_HIGH_GET
/**
* kmap_high_get - pin a highmem page into memory
* @page: &struct page to pin
*
* Returns the page's current virtual memory address, or NULL if no mapping
* exists. If and only if a non null address is returned then a
* matching call to kunmap_high() is necessary.
*
* This can be called from any context.
*/
void *kmap_high_get(struct page *page)
{
unsigned long vaddr, flags;
lock_kmap_any(flags);
vaddr = (unsigned long)page_address(page);
if (vaddr) {
BUG_ON(pkmap_count[PKMAP_NR(vaddr)] < 1);
pkmap_count[PKMAP_NR(vaddr)]++;
}
unlock_kmap_any(flags);
return (void *) vaddr;
}
#endif
/**
* kunmap_high - unmap a highmem page into memory
* @page: &struct page to unmap
*
* If ARCH_NEEDS_KMAP_HIGH_GET is not defined then this may be called
* only from user context.
*/
void kunmap_high(struct page *page)
{
unsigned long vaddr;
unsigned long nr;
unsigned long flags;
int need_wakeup;
unsigned int color = get_pkmap_color(page);
wait_queue_head_t *pkmap_map_wait;
lock_kmap_any(flags);
vaddr = (unsigned long)page_address(page);
BUG_ON(!vaddr);
nr = PKMAP_NR(vaddr);
/*
* A count must never go down to zero
* without a TLB flush!
*/
need_wakeup = 0;
switch (--pkmap_count[nr]) {
case 0:
BUG();
case 1:
/*
* Avoid an unnecessary wake_up() function call.
* The common case is pkmap_count[] == 1, but
* no waiters.
* The tasks queued in the wait-queue are guarded
* by both the lock in the wait-queue-head and by
* the kmap_lock. As the kmap_lock is held here,
* no need for the wait-queue-head's lock. Simply
* test if the queue is empty.
*/
pkmap_map_wait = get_pkmap_wait_queue_head(color);
need_wakeup = waitqueue_active(pkmap_map_wait);
}
unlock_kmap_any(flags);
/* do wake-up, if needed, race-free outside of the spin lock */
if (need_wakeup)
wake_up(pkmap_map_wait);
}
EXPORT_SYMBOL(kunmap_high);
void zero_user_segments(struct page *page, unsigned start1, unsigned end1,
unsigned start2, unsigned end2)
{
unsigned int i;
BUG_ON(end1 > page_size(page) || end2 > page_size(page));
if (start1 >= end1)
start1 = end1 = 0;
if (start2 >= end2)
start2 = end2 = 0;
for (i = 0; i < compound_nr(page); i++) {
void *kaddr = NULL;
if (start1 >= PAGE_SIZE) {
start1 -= PAGE_SIZE;
end1 -= PAGE_SIZE;
} else {
unsigned this_end = min_t(unsigned, end1, PAGE_SIZE);
if (end1 > start1) {
kaddr = kmap_local_page(page + i);
memset(kaddr + start1, 0, this_end - start1);
}
end1 -= this_end;
start1 = 0;
}
if (start2 >= PAGE_SIZE) {
start2 -= PAGE_SIZE;
end2 -= PAGE_SIZE;
} else {
unsigned this_end = min_t(unsigned, end2, PAGE_SIZE);
if (end2 > start2) {
if (!kaddr)
kaddr = kmap_local_page(page + i);
memset(kaddr + start2, 0, this_end - start2);
}
end2 -= this_end;
start2 = 0;
}
if (kaddr) {
kunmap_local(kaddr);
flush_dcache_page(page + i);
}
if (!end1 && !end2)
break;
}
BUG_ON((start1 | start2 | end1 | end2) != 0);
}
EXPORT_SYMBOL(zero_user_segments);
#endif /* CONFIG_HIGHMEM */
#ifdef CONFIG_KMAP_LOCAL
#include <asm/kmap_size.h>
/*
* With DEBUG_KMAP_LOCAL the stack depth is doubled and every second
* slot is unused which acts as a guard page
*/
#ifdef CONFIG_DEBUG_KMAP_LOCAL
# define KM_INCR 2
#else
# define KM_INCR 1
#endif
static inline int kmap_local_idx_push(void)
{
WARN_ON_ONCE(in_hardirq() && !irqs_disabled());
current->kmap_ctrl.idx += KM_INCR;
BUG_ON(current->kmap_ctrl.idx >= KM_MAX_IDX);
return current->kmap_ctrl.idx - 1;
}
static inline int kmap_local_idx(void)
{
return current->kmap_ctrl.idx - 1;
}
static inline void kmap_local_idx_pop(void)
{
current->kmap_ctrl.idx -= KM_INCR;
BUG_ON(current->kmap_ctrl.idx < 0);
}
#ifndef arch_kmap_local_post_map
# define arch_kmap_local_post_map(vaddr, pteval) do { } while (0)
#endif
#ifndef arch_kmap_local_pre_unmap
# define arch_kmap_local_pre_unmap(vaddr) do { } while (0)
#endif
#ifndef arch_kmap_local_post_unmap
# define arch_kmap_local_post_unmap(vaddr) do { } while (0)
#endif
#ifndef arch_kmap_local_unmap_idx
#define arch_kmap_local_unmap_idx(idx, vaddr) kmap_local_calc_idx(idx)
#endif
#ifndef arch_kmap_local_high_get
static inline void *arch_kmap_local_high_get(struct page *page)
{
return NULL;
}
#endif
#ifndef arch_kmap_local_set_pte
#define arch_kmap_local_set_pte(mm, vaddr, ptep, ptev) \
set_pte_at(mm, vaddr, ptep, ptev)
#endif
/* Unmap a local mapping which was obtained by kmap_high_get() */
static inline bool kmap_high_unmap_local(unsigned long vaddr)
{
#ifdef ARCH_NEEDS_KMAP_HIGH_GET
if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP)) {
kunmap_high(pte_page(ptep_get(&pkmap_page_table[PKMAP_NR(vaddr)])));
return true;
}
#endif
return false;
}
static pte_t *__kmap_pte;
static pte_t *kmap_get_pte(unsigned long vaddr, int idx)
{
if (IS_ENABLED(CONFIG_KMAP_LOCAL_NON_LINEAR_PTE_ARRAY))
/*
* Set by the arch if __kmap_pte[-idx] does not produce
* the correct entry.
*/
return virt_to_kpte(vaddr);
if (!__kmap_pte)
__kmap_pte = virt_to_kpte(__fix_to_virt(FIX_KMAP_BEGIN));
return &__kmap_pte[-idx];
}
void *__kmap_local_pfn_prot(unsigned long pfn, pgprot_t prot)
{
pte_t pteval, *kmap_pte;
unsigned long vaddr;
int idx;
/*
* Disable migration so resulting virtual address is stable
* across preemption.
*/
migrate_disable();
preempt_disable();
idx = arch_kmap_local_map_idx(kmap_local_idx_push(), pfn);
vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
kmap_pte = kmap_get_pte(vaddr, idx);
BUG_ON(!pte_none(ptep_get(kmap_pte)));
pteval = pfn_pte(pfn, prot);
arch_kmap_local_set_pte(&init_mm, vaddr, kmap_pte, pteval);
arch_kmap_local_post_map(vaddr, pteval);
current->kmap_ctrl.pteval[kmap_local_idx()] = pteval;
preempt_enable();
return (void *)vaddr;
}
EXPORT_SYMBOL_GPL(__kmap_local_pfn_prot);
void *__kmap_local_page_prot(struct page *page, pgprot_t prot)
{
void *kmap;
/*
* To broaden the usage of the actual kmap_local() machinery always map
* pages when debugging is enabled and the architecture has no problems
* with alias mappings.
*/
if (!IS_ENABLED(CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP) && !PageHighMem(page))
return page_address(page);
/* Try kmap_high_get() if architecture has it enabled */
kmap = arch_kmap_local_high_get(page);
if (kmap)
return kmap;
return __kmap_local_pfn_prot(page_to_pfn(page), prot);
}
EXPORT_SYMBOL(__kmap_local_page_prot);
void kunmap_local_indexed(const void *vaddr)
{
unsigned long addr = (unsigned long) vaddr & PAGE_MASK;
pte_t *kmap_pte;
int idx;
if (addr < __fix_to_virt(FIX_KMAP_END) ||
addr > __fix_to_virt(FIX_KMAP_BEGIN)) {
if (IS_ENABLED(CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP)) {
/* This _should_ never happen! See above. */
WARN_ON_ONCE(1);
return;
}
/*
* Handle mappings which were obtained by kmap_high_get()
* first as the virtual address of such mappings is below
* PAGE_OFFSET. Warn for all other addresses which are in
* the user space part of the virtual address space.
*/
if (!kmap_high_unmap_local(addr))
WARN_ON_ONCE(addr < PAGE_OFFSET);
return;
}
preempt_disable();
idx = arch_kmap_local_unmap_idx(kmap_local_idx(), addr);
WARN_ON_ONCE(addr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
kmap_pte = kmap_get_pte(addr, idx);
arch_kmap_local_pre_unmap(addr);
pte_clear(&init_mm, addr, kmap_pte);
arch_kmap_local_post_unmap(addr);
current->kmap_ctrl.pteval[kmap_local_idx()] = __pte(0);
kmap_local_idx_pop();
preempt_enable();
migrate_enable();
}
EXPORT_SYMBOL(kunmap_local_indexed);
/*
* Invoked before switch_to(). This is safe even when during or after
* clearing the maps an interrupt which needs a kmap_local happens because
* the task::kmap_ctrl.idx is not modified by the unmapping code so a
* nested kmap_local will use the next unused index and restore the index
* on unmap. The already cleared kmaps of the outgoing task are irrelevant
* because the interrupt context does not know about them. The same applies
* when scheduling back in for an interrupt which happens before the
* restore is complete.
*/
void __kmap_local_sched_out(void)
{
struct task_struct *tsk = current;
pte_t *kmap_pte;
int i;
/* Clear kmaps */
for (i = 0; i < tsk->kmap_ctrl.idx; i++) {
pte_t pteval = tsk->kmap_ctrl.pteval[i];
unsigned long addr;
int idx;
/* With debug all even slots are unmapped and act as guard */
if (IS_ENABLED(CONFIG_DEBUG_KMAP_LOCAL) && !(i & 0x01)) {
WARN_ON_ONCE(pte_val(pteval) != 0);
continue;
}
if (WARN_ON_ONCE(pte_none(pteval)))
continue;
/*
* This is a horrible hack for XTENSA to calculate the
* coloured PTE index. Uses the PFN encoded into the pteval
* and the map index calculation because the actual mapped
* virtual address is not stored in task::kmap_ctrl.
* For any sane architecture this is optimized out.
*/
idx = arch_kmap_local_map_idx(i, pte_pfn(pteval));
addr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
kmap_pte = kmap_get_pte(addr, idx);
arch_kmap_local_pre_unmap(addr);
pte_clear(&init_mm, addr, kmap_pte);
arch_kmap_local_post_unmap(addr);
}
}
void __kmap_local_sched_in(void)
{
struct task_struct *tsk = current;
pte_t *kmap_pte;
int i;
/* Restore kmaps */
for (i = 0; i < tsk->kmap_ctrl.idx; i++) {
pte_t pteval = tsk->kmap_ctrl.pteval[i];
unsigned long addr;
int idx;
/* With debug all even slots are unmapped and act as guard */
if (IS_ENABLED(CONFIG_DEBUG_KMAP_LOCAL) && !(i & 0x01)) {
WARN_ON_ONCE(pte_val(pteval) != 0);
continue;
}
if (WARN_ON_ONCE(pte_none(pteval)))
continue;
/* See comment in __kmap_local_sched_out() */
idx = arch_kmap_local_map_idx(i, pte_pfn(pteval));
addr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
kmap_pte = kmap_get_pte(addr, idx);
set_pte_at(&init_mm, addr, kmap_pte, pteval);
arch_kmap_local_post_map(addr, pteval);
}
}
void kmap_local_fork(struct task_struct *tsk)
{
if (WARN_ON_ONCE(tsk->kmap_ctrl.idx))
memset(&tsk->kmap_ctrl, 0, sizeof(tsk->kmap_ctrl));
}
#endif
#if defined(HASHED_PAGE_VIRTUAL)
#define PA_HASH_ORDER 7
/*
* Describes one page->virtual association
*/
struct page_address_map {
struct page *page;
void *virtual;
struct list_head list;
};
static struct page_address_map page_address_maps[LAST_PKMAP];
/*
* Hash table bucket
*/
static struct page_address_slot {
struct list_head lh; /* List of page_address_maps */
spinlock_t lock; /* Protect this bucket's list */
} ____cacheline_aligned_in_smp page_address_htable[1<<PA_HASH_ORDER];
static struct page_address_slot *page_slot(const struct page *page)
{
return &page_address_htable[hash_ptr(page, PA_HASH_ORDER)];
}
/**
* page_address - get the mapped virtual address of a page
* @page: &struct page to get the virtual address of
*
* Returns the page's virtual address.
*/
void *page_address(const struct page *page)
{
unsigned long flags;
void *ret;
struct page_address_slot *pas;
if (!PageHighMem(page))
return lowmem_page_address(page);
pas = page_slot(page);
ret = NULL;
spin_lock_irqsave(&pas->lock, flags);
if (!list_empty(&pas->lh)) {
struct page_address_map *pam;
list_for_each_entry(pam, &pas->lh, list) {
if (pam->page == page) {
ret = pam->virtual;
break;
}
}
}
spin_unlock_irqrestore(&pas->lock, flags);
return ret;
}
EXPORT_SYMBOL(page_address);
/**
* set_page_address - set a page's virtual address
* @page: &struct page to set
* @virtual: virtual address to use
*/
void set_page_address(struct page *page, void *virtual)
{
unsigned long flags;
struct page_address_slot *pas;
struct page_address_map *pam;
BUG_ON(!PageHighMem(page));
pas = page_slot(page);
if (virtual) { /* Add */
pam = &page_address_maps[PKMAP_NR((unsigned long)virtual)];
pam->page = page;
pam->virtual = virtual;
spin_lock_irqsave(&pas->lock, flags);
list_add_tail(&pam->list, &pas->lh);
spin_unlock_irqrestore(&pas->lock, flags);
} else { /* Remove */
spin_lock_irqsave(&pas->lock, flags);
list_for_each_entry(pam, &pas->lh, list) {
if (pam->page == page) {
list_del(&pam->list);
break;
}
}
spin_unlock_irqrestore(&pas->lock, flags);
}
return;
}
void __init page_address_init(void)
{
int i;
for (i = 0; i < ARRAY_SIZE(page_address_htable); i++) {
INIT_LIST_HEAD(&page_address_htable[i].lh);
spin_lock_init(&page_address_htable[i].lock);
}
}
#endif /* defined(HASHED_PAGE_VIRTUAL) */
| linux-master | mm/highmem.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/mm/swap.c
*
* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
*/
/*
* This file contains the default values for the operation of the
* Linux VM subsystem. Fine-tuning documentation can be found in
* Documentation/admin-guide/sysctl/vm.rst.
* Started 18.12.91
* Swap aging added 23.2.95, Stephen Tweedie.
* Buffermem limits added 12.3.98, Rik van Riel.
*/
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/kernel_stat.h>
#include <linux/swap.h>
#include <linux/mman.h>
#include <linux/pagemap.h>
#include <linux/pagevec.h>
#include <linux/init.h>
#include <linux/export.h>
#include <linux/mm_inline.h>
#include <linux/percpu_counter.h>
#include <linux/memremap.h>
#include <linux/percpu.h>
#include <linux/cpu.h>
#include <linux/notifier.h>
#include <linux/backing-dev.h>
#include <linux/memcontrol.h>
#include <linux/gfp.h>
#include <linux/uio.h>
#include <linux/hugetlb.h>
#include <linux/page_idle.h>
#include <linux/local_lock.h>
#include <linux/buffer_head.h>
#include "internal.h"
#define CREATE_TRACE_POINTS
#include <trace/events/pagemap.h>
/* How many pages do we try to swap or page in/out together? As a power of 2 */
int page_cluster;
const int page_cluster_max = 31;
/* Protecting only lru_rotate.fbatch which requires disabling interrupts */
struct lru_rotate {
local_lock_t lock;
struct folio_batch fbatch;
};
static DEFINE_PER_CPU(struct lru_rotate, lru_rotate) = {
.lock = INIT_LOCAL_LOCK(lock),
};
/*
* The following folio batches are grouped together because they are protected
* by disabling preemption (and interrupts remain enabled).
*/
struct cpu_fbatches {
local_lock_t lock;
struct folio_batch lru_add;
struct folio_batch lru_deactivate_file;
struct folio_batch lru_deactivate;
struct folio_batch lru_lazyfree;
#ifdef CONFIG_SMP
struct folio_batch activate;
#endif
};
static DEFINE_PER_CPU(struct cpu_fbatches, cpu_fbatches) = {
.lock = INIT_LOCAL_LOCK(lock),
};
/*
* This path almost never happens for VM activity - pages are normally freed
* in batches. But it gets used by networking - and for compound pages.
*/
static void __page_cache_release(struct folio *folio)
{
if (folio_test_lru(folio)) {
struct lruvec *lruvec;
unsigned long flags;
lruvec = folio_lruvec_lock_irqsave(folio, &flags);
lruvec_del_folio(lruvec, folio);
__folio_clear_lru_flags(folio);
unlock_page_lruvec_irqrestore(lruvec, flags);
}
/* See comment on folio_test_mlocked in release_pages() */
if (unlikely(folio_test_mlocked(folio))) {
long nr_pages = folio_nr_pages(folio);
__folio_clear_mlocked(folio);
zone_stat_mod_folio(folio, NR_MLOCK, -nr_pages);
count_vm_events(UNEVICTABLE_PGCLEARED, nr_pages);
}
}
static void __folio_put_small(struct folio *folio)
{
__page_cache_release(folio);
mem_cgroup_uncharge(folio);
free_unref_page(&folio->page, 0);
}
static void __folio_put_large(struct folio *folio)
{
/*
* __page_cache_release() is supposed to be called for thp, not for
* hugetlb. This is because hugetlb page does never have PageLRU set
* (it's never listed to any LRU lists) and no memcg routines should
* be called for hugetlb (it has a separate hugetlb_cgroup.)
*/
if (!folio_test_hugetlb(folio))
__page_cache_release(folio);
destroy_large_folio(folio);
}
void __folio_put(struct folio *folio)
{
if (unlikely(folio_is_zone_device(folio)))
free_zone_device_page(&folio->page);
else if (unlikely(folio_test_large(folio)))
__folio_put_large(folio);
else
__folio_put_small(folio);
}
EXPORT_SYMBOL(__folio_put);
/**
* put_pages_list() - release a list of pages
* @pages: list of pages threaded on page->lru
*
* Release a list of pages which are strung together on page.lru.
*/
void put_pages_list(struct list_head *pages)
{
struct folio *folio, *next;
list_for_each_entry_safe(folio, next, pages, lru) {
if (!folio_put_testzero(folio)) {
list_del(&folio->lru);
continue;
}
if (folio_test_large(folio)) {
list_del(&folio->lru);
__folio_put_large(folio);
continue;
}
/* LRU flag must be clear because it's passed using the lru */
}
free_unref_page_list(pages);
INIT_LIST_HEAD(pages);
}
EXPORT_SYMBOL(put_pages_list);
typedef void (*move_fn_t)(struct lruvec *lruvec, struct folio *folio);
static void lru_add_fn(struct lruvec *lruvec, struct folio *folio)
{
int was_unevictable = folio_test_clear_unevictable(folio);
long nr_pages = folio_nr_pages(folio);
VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
/*
* Is an smp_mb__after_atomic() still required here, before
* folio_evictable() tests the mlocked flag, to rule out the possibility
* of stranding an evictable folio on an unevictable LRU? I think
* not, because __munlock_folio() only clears the mlocked flag
* while the LRU lock is held.
*
* (That is not true of __page_cache_release(), and not necessarily
* true of release_pages(): but those only clear the mlocked flag after
* folio_put_testzero() has excluded any other users of the folio.)
*/
if (folio_evictable(folio)) {
if (was_unevictable)
__count_vm_events(UNEVICTABLE_PGRESCUED, nr_pages);
} else {
folio_clear_active(folio);
folio_set_unevictable(folio);
/*
* folio->mlock_count = !!folio_test_mlocked(folio)?
* But that leaves __mlock_folio() in doubt whether another
* actor has already counted the mlock or not. Err on the
* safe side, underestimate, let page reclaim fix it, rather
* than leaving a page on the unevictable LRU indefinitely.
*/
folio->mlock_count = 0;
if (!was_unevictable)
__count_vm_events(UNEVICTABLE_PGCULLED, nr_pages);
}
lruvec_add_folio(lruvec, folio);
trace_mm_lru_insertion(folio);
}
static void folio_batch_move_lru(struct folio_batch *fbatch, move_fn_t move_fn)
{
int i;
struct lruvec *lruvec = NULL;
unsigned long flags = 0;
for (i = 0; i < folio_batch_count(fbatch); i++) {
struct folio *folio = fbatch->folios[i];
/* block memcg migration while the folio moves between lru */
if (move_fn != lru_add_fn && !folio_test_clear_lru(folio))
continue;
lruvec = folio_lruvec_relock_irqsave(folio, lruvec, &flags);
move_fn(lruvec, folio);
folio_set_lru(folio);
}
if (lruvec)
unlock_page_lruvec_irqrestore(lruvec, flags);
folios_put(fbatch->folios, folio_batch_count(fbatch));
folio_batch_reinit(fbatch);
}
static void folio_batch_add_and_move(struct folio_batch *fbatch,
struct folio *folio, move_fn_t move_fn)
{
if (folio_batch_add(fbatch, folio) && !folio_test_large(folio) &&
!lru_cache_disabled())
return;
folio_batch_move_lru(fbatch, move_fn);
}
static void lru_move_tail_fn(struct lruvec *lruvec, struct folio *folio)
{
if (!folio_test_unevictable(folio)) {
lruvec_del_folio(lruvec, folio);
folio_clear_active(folio);
lruvec_add_folio_tail(lruvec, folio);
__count_vm_events(PGROTATED, folio_nr_pages(folio));
}
}
/*
* Writeback is about to end against a folio which has been marked for
* immediate reclaim. If it still appears to be reclaimable, move it
* to the tail of the inactive list.
*
* folio_rotate_reclaimable() must disable IRQs, to prevent nasty races.
*/
void folio_rotate_reclaimable(struct folio *folio)
{
if (!folio_test_locked(folio) && !folio_test_dirty(folio) &&
!folio_test_unevictable(folio) && folio_test_lru(folio)) {
struct folio_batch *fbatch;
unsigned long flags;
folio_get(folio);
local_lock_irqsave(&lru_rotate.lock, flags);
fbatch = this_cpu_ptr(&lru_rotate.fbatch);
folio_batch_add_and_move(fbatch, folio, lru_move_tail_fn);
local_unlock_irqrestore(&lru_rotate.lock, flags);
}
}
void lru_note_cost(struct lruvec *lruvec, bool file,
unsigned int nr_io, unsigned int nr_rotated)
{
unsigned long cost;
/*
* Reflect the relative cost of incurring IO and spending CPU
* time on rotations. This doesn't attempt to make a precise
* comparison, it just says: if reloads are about comparable
* between the LRU lists, or rotations are overwhelmingly
* different between them, adjust scan balance for CPU work.
*/
cost = nr_io * SWAP_CLUSTER_MAX + nr_rotated;
do {
unsigned long lrusize;
/*
* Hold lruvec->lru_lock is safe here, since
* 1) The pinned lruvec in reclaim, or
* 2) From a pre-LRU page during refault (which also holds the
* rcu lock, so would be safe even if the page was on the LRU
* and could move simultaneously to a new lruvec).
*/
spin_lock_irq(&lruvec->lru_lock);
/* Record cost event */
if (file)
lruvec->file_cost += cost;
else
lruvec->anon_cost += cost;
/*
* Decay previous events
*
* Because workloads change over time (and to avoid
* overflow) we keep these statistics as a floating
* average, which ends up weighing recent refaults
* more than old ones.
*/
lrusize = lruvec_page_state(lruvec, NR_INACTIVE_ANON) +
lruvec_page_state(lruvec, NR_ACTIVE_ANON) +
lruvec_page_state(lruvec, NR_INACTIVE_FILE) +
lruvec_page_state(lruvec, NR_ACTIVE_FILE);
if (lruvec->file_cost + lruvec->anon_cost > lrusize / 4) {
lruvec->file_cost /= 2;
lruvec->anon_cost /= 2;
}
spin_unlock_irq(&lruvec->lru_lock);
} while ((lruvec = parent_lruvec(lruvec)));
}
void lru_note_cost_refault(struct folio *folio)
{
lru_note_cost(folio_lruvec(folio), folio_is_file_lru(folio),
folio_nr_pages(folio), 0);
}
static void folio_activate_fn(struct lruvec *lruvec, struct folio *folio)
{
if (!folio_test_active(folio) && !folio_test_unevictable(folio)) {
long nr_pages = folio_nr_pages(folio);
lruvec_del_folio(lruvec, folio);
folio_set_active(folio);
lruvec_add_folio(lruvec, folio);
trace_mm_lru_activate(folio);
__count_vm_events(PGACTIVATE, nr_pages);
__count_memcg_events(lruvec_memcg(lruvec), PGACTIVATE,
nr_pages);
}
}
#ifdef CONFIG_SMP
static void folio_activate_drain(int cpu)
{
struct folio_batch *fbatch = &per_cpu(cpu_fbatches.activate, cpu);
if (folio_batch_count(fbatch))
folio_batch_move_lru(fbatch, folio_activate_fn);
}
void folio_activate(struct folio *folio)
{
if (folio_test_lru(folio) && !folio_test_active(folio) &&
!folio_test_unevictable(folio)) {
struct folio_batch *fbatch;
folio_get(folio);
local_lock(&cpu_fbatches.lock);
fbatch = this_cpu_ptr(&cpu_fbatches.activate);
folio_batch_add_and_move(fbatch, folio, folio_activate_fn);
local_unlock(&cpu_fbatches.lock);
}
}
#else
static inline void folio_activate_drain(int cpu)
{
}
void folio_activate(struct folio *folio)
{
struct lruvec *lruvec;
if (folio_test_clear_lru(folio)) {
lruvec = folio_lruvec_lock_irq(folio);
folio_activate_fn(lruvec, folio);
unlock_page_lruvec_irq(lruvec);
folio_set_lru(folio);
}
}
#endif
static void __lru_cache_activate_folio(struct folio *folio)
{
struct folio_batch *fbatch;
int i;
local_lock(&cpu_fbatches.lock);
fbatch = this_cpu_ptr(&cpu_fbatches.lru_add);
/*
* Search backwards on the optimistic assumption that the folio being
* activated has just been added to this batch. Note that only
* the local batch is examined as a !LRU folio could be in the
* process of being released, reclaimed, migrated or on a remote
* batch that is currently being drained. Furthermore, marking
* a remote batch's folio active potentially hits a race where
* a folio is marked active just after it is added to the inactive
* list causing accounting errors and BUG_ON checks to trigger.
*/
for (i = folio_batch_count(fbatch) - 1; i >= 0; i--) {
struct folio *batch_folio = fbatch->folios[i];
if (batch_folio == folio) {
folio_set_active(folio);
break;
}
}
local_unlock(&cpu_fbatches.lock);
}
#ifdef CONFIG_LRU_GEN
static void folio_inc_refs(struct folio *folio)
{
unsigned long new_flags, old_flags = READ_ONCE(folio->flags);
if (folio_test_unevictable(folio))
return;
if (!folio_test_referenced(folio)) {
folio_set_referenced(folio);
return;
}
if (!folio_test_workingset(folio)) {
folio_set_workingset(folio);
return;
}
/* see the comment on MAX_NR_TIERS */
do {
new_flags = old_flags & LRU_REFS_MASK;
if (new_flags == LRU_REFS_MASK)
break;
new_flags += BIT(LRU_REFS_PGOFF);
new_flags |= old_flags & ~LRU_REFS_MASK;
} while (!try_cmpxchg(&folio->flags, &old_flags, new_flags));
}
#else
static void folio_inc_refs(struct folio *folio)
{
}
#endif /* CONFIG_LRU_GEN */
/*
* Mark a page as having seen activity.
*
* inactive,unreferenced -> inactive,referenced
* inactive,referenced -> active,unreferenced
* active,unreferenced -> active,referenced
*
* When a newly allocated page is not yet visible, so safe for non-atomic ops,
* __SetPageReferenced(page) may be substituted for mark_page_accessed(page).
*/
void folio_mark_accessed(struct folio *folio)
{
if (lru_gen_enabled()) {
folio_inc_refs(folio);
return;
}
if (!folio_test_referenced(folio)) {
folio_set_referenced(folio);
} else if (folio_test_unevictable(folio)) {
/*
* Unevictable pages are on the "LRU_UNEVICTABLE" list. But,
* this list is never rotated or maintained, so marking an
* unevictable page accessed has no effect.
*/
} else if (!folio_test_active(folio)) {
/*
* If the folio is on the LRU, queue it for activation via
* cpu_fbatches.activate. Otherwise, assume the folio is in a
* folio_batch, mark it active and it'll be moved to the active
* LRU on the next drain.
*/
if (folio_test_lru(folio))
folio_activate(folio);
else
__lru_cache_activate_folio(folio);
folio_clear_referenced(folio);
workingset_activation(folio);
}
if (folio_test_idle(folio))
folio_clear_idle(folio);
}
EXPORT_SYMBOL(folio_mark_accessed);
/**
* folio_add_lru - Add a folio to an LRU list.
* @folio: The folio to be added to the LRU.
*
* Queue the folio for addition to the LRU. The decision on whether
* to add the page to the [in]active [file|anon] list is deferred until the
* folio_batch is drained. This gives a chance for the caller of folio_add_lru()
* have the folio added to the active list using folio_mark_accessed().
*/
void folio_add_lru(struct folio *folio)
{
struct folio_batch *fbatch;
VM_BUG_ON_FOLIO(folio_test_active(folio) &&
folio_test_unevictable(folio), folio);
VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
/* see the comment in lru_gen_add_folio() */
if (lru_gen_enabled() && !folio_test_unevictable(folio) &&
lru_gen_in_fault() && !(current->flags & PF_MEMALLOC))
folio_set_active(folio);
folio_get(folio);
local_lock(&cpu_fbatches.lock);
fbatch = this_cpu_ptr(&cpu_fbatches.lru_add);
folio_batch_add_and_move(fbatch, folio, lru_add_fn);
local_unlock(&cpu_fbatches.lock);
}
EXPORT_SYMBOL(folio_add_lru);
/**
* folio_add_lru_vma() - Add a folio to the appropate LRU list for this VMA.
* @folio: The folio to be added to the LRU.
* @vma: VMA in which the folio is mapped.
*
* If the VMA is mlocked, @folio is added to the unevictable list.
* Otherwise, it is treated the same way as folio_add_lru().
*/
void folio_add_lru_vma(struct folio *folio, struct vm_area_struct *vma)
{
VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
if (unlikely((vma->vm_flags & (VM_LOCKED | VM_SPECIAL)) == VM_LOCKED))
mlock_new_folio(folio);
else
folio_add_lru(folio);
}
/*
* If the folio cannot be invalidated, it is moved to the
* inactive list to speed up its reclaim. It is moved to the
* head of the list, rather than the tail, to give the flusher
* threads some time to write it out, as this is much more
* effective than the single-page writeout from reclaim.
*
* If the folio isn't mapped and dirty/writeback, the folio
* could be reclaimed asap using the reclaim flag.
*
* 1. active, mapped folio -> none
* 2. active, dirty/writeback folio -> inactive, head, reclaim
* 3. inactive, mapped folio -> none
* 4. inactive, dirty/writeback folio -> inactive, head, reclaim
* 5. inactive, clean -> inactive, tail
* 6. Others -> none
*
* In 4, it moves to the head of the inactive list so the folio is
* written out by flusher threads as this is much more efficient
* than the single-page writeout from reclaim.
*/
static void lru_deactivate_file_fn(struct lruvec *lruvec, struct folio *folio)
{
bool active = folio_test_active(folio);
long nr_pages = folio_nr_pages(folio);
if (folio_test_unevictable(folio))
return;
/* Some processes are using the folio */
if (folio_mapped(folio))
return;
lruvec_del_folio(lruvec, folio);
folio_clear_active(folio);
folio_clear_referenced(folio);
if (folio_test_writeback(folio) || folio_test_dirty(folio)) {
/*
* Setting the reclaim flag could race with
* folio_end_writeback() and confuse readahead. But the
* race window is _really_ small and it's not a critical
* problem.
*/
lruvec_add_folio(lruvec, folio);
folio_set_reclaim(folio);
} else {
/*
* The folio's writeback ended while it was in the batch.
* We move that folio to the tail of the inactive list.
*/
lruvec_add_folio_tail(lruvec, folio);
__count_vm_events(PGROTATED, nr_pages);
}
if (active) {
__count_vm_events(PGDEACTIVATE, nr_pages);
__count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE,
nr_pages);
}
}
static void lru_deactivate_fn(struct lruvec *lruvec, struct folio *folio)
{
if (!folio_test_unevictable(folio) && (folio_test_active(folio) || lru_gen_enabled())) {
long nr_pages = folio_nr_pages(folio);
lruvec_del_folio(lruvec, folio);
folio_clear_active(folio);
folio_clear_referenced(folio);
lruvec_add_folio(lruvec, folio);
__count_vm_events(PGDEACTIVATE, nr_pages);
__count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE,
nr_pages);
}
}
static void lru_lazyfree_fn(struct lruvec *lruvec, struct folio *folio)
{
if (folio_test_anon(folio) && folio_test_swapbacked(folio) &&
!folio_test_swapcache(folio) && !folio_test_unevictable(folio)) {
long nr_pages = folio_nr_pages(folio);
lruvec_del_folio(lruvec, folio);
folio_clear_active(folio);
folio_clear_referenced(folio);
/*
* Lazyfree folios are clean anonymous folios. They have
* the swapbacked flag cleared, to distinguish them from normal
* anonymous folios
*/
folio_clear_swapbacked(folio);
lruvec_add_folio(lruvec, folio);
__count_vm_events(PGLAZYFREE, nr_pages);
__count_memcg_events(lruvec_memcg(lruvec), PGLAZYFREE,
nr_pages);
}
}
/*
* Drain pages out of the cpu's folio_batch.
* Either "cpu" is the current CPU, and preemption has already been
* disabled; or "cpu" is being hot-unplugged, and is already dead.
*/
void lru_add_drain_cpu(int cpu)
{
struct cpu_fbatches *fbatches = &per_cpu(cpu_fbatches, cpu);
struct folio_batch *fbatch = &fbatches->lru_add;
if (folio_batch_count(fbatch))
folio_batch_move_lru(fbatch, lru_add_fn);
fbatch = &per_cpu(lru_rotate.fbatch, cpu);
/* Disabling interrupts below acts as a compiler barrier. */
if (data_race(folio_batch_count(fbatch))) {
unsigned long flags;
/* No harm done if a racing interrupt already did this */
local_lock_irqsave(&lru_rotate.lock, flags);
folio_batch_move_lru(fbatch, lru_move_tail_fn);
local_unlock_irqrestore(&lru_rotate.lock, flags);
}
fbatch = &fbatches->lru_deactivate_file;
if (folio_batch_count(fbatch))
folio_batch_move_lru(fbatch, lru_deactivate_file_fn);
fbatch = &fbatches->lru_deactivate;
if (folio_batch_count(fbatch))
folio_batch_move_lru(fbatch, lru_deactivate_fn);
fbatch = &fbatches->lru_lazyfree;
if (folio_batch_count(fbatch))
folio_batch_move_lru(fbatch, lru_lazyfree_fn);
folio_activate_drain(cpu);
}
/**
* deactivate_file_folio() - Deactivate a file folio.
* @folio: Folio to deactivate.
*
* This function hints to the VM that @folio is a good reclaim candidate,
* for example if its invalidation fails due to the folio being dirty
* or under writeback.
*
* Context: Caller holds a reference on the folio.
*/
void deactivate_file_folio(struct folio *folio)
{
struct folio_batch *fbatch;
/* Deactivating an unevictable folio will not accelerate reclaim */
if (folio_test_unevictable(folio))
return;
folio_get(folio);
local_lock(&cpu_fbatches.lock);
fbatch = this_cpu_ptr(&cpu_fbatches.lru_deactivate_file);
folio_batch_add_and_move(fbatch, folio, lru_deactivate_file_fn);
local_unlock(&cpu_fbatches.lock);
}
/*
* folio_deactivate - deactivate a folio
* @folio: folio to deactivate
*
* folio_deactivate() moves @folio to the inactive list if @folio was on the
* active list and was not unevictable. This is done to accelerate the
* reclaim of @folio.
*/
void folio_deactivate(struct folio *folio)
{
if (folio_test_lru(folio) && !folio_test_unevictable(folio) &&
(folio_test_active(folio) || lru_gen_enabled())) {
struct folio_batch *fbatch;
folio_get(folio);
local_lock(&cpu_fbatches.lock);
fbatch = this_cpu_ptr(&cpu_fbatches.lru_deactivate);
folio_batch_add_and_move(fbatch, folio, lru_deactivate_fn);
local_unlock(&cpu_fbatches.lock);
}
}
/**
* folio_mark_lazyfree - make an anon folio lazyfree
* @folio: folio to deactivate
*
* folio_mark_lazyfree() moves @folio to the inactive file list.
* This is done to accelerate the reclaim of @folio.
*/
void folio_mark_lazyfree(struct folio *folio)
{
if (folio_test_lru(folio) && folio_test_anon(folio) &&
folio_test_swapbacked(folio) && !folio_test_swapcache(folio) &&
!folio_test_unevictable(folio)) {
struct folio_batch *fbatch;
folio_get(folio);
local_lock(&cpu_fbatches.lock);
fbatch = this_cpu_ptr(&cpu_fbatches.lru_lazyfree);
folio_batch_add_and_move(fbatch, folio, lru_lazyfree_fn);
local_unlock(&cpu_fbatches.lock);
}
}
void lru_add_drain(void)
{
local_lock(&cpu_fbatches.lock);
lru_add_drain_cpu(smp_processor_id());
local_unlock(&cpu_fbatches.lock);
mlock_drain_local();
}
/*
* It's called from per-cpu workqueue context in SMP case so
* lru_add_drain_cpu and invalidate_bh_lrus_cpu should run on
* the same cpu. It shouldn't be a problem in !SMP case since
* the core is only one and the locks will disable preemption.
*/
static void lru_add_and_bh_lrus_drain(void)
{
local_lock(&cpu_fbatches.lock);
lru_add_drain_cpu(smp_processor_id());
local_unlock(&cpu_fbatches.lock);
invalidate_bh_lrus_cpu();
mlock_drain_local();
}
void lru_add_drain_cpu_zone(struct zone *zone)
{
local_lock(&cpu_fbatches.lock);
lru_add_drain_cpu(smp_processor_id());
drain_local_pages(zone);
local_unlock(&cpu_fbatches.lock);
mlock_drain_local();
}
#ifdef CONFIG_SMP
static DEFINE_PER_CPU(struct work_struct, lru_add_drain_work);
static void lru_add_drain_per_cpu(struct work_struct *dummy)
{
lru_add_and_bh_lrus_drain();
}
static bool cpu_needs_drain(unsigned int cpu)
{
struct cpu_fbatches *fbatches = &per_cpu(cpu_fbatches, cpu);
/* Check these in order of likelihood that they're not zero */
return folio_batch_count(&fbatches->lru_add) ||
data_race(folio_batch_count(&per_cpu(lru_rotate.fbatch, cpu))) ||
folio_batch_count(&fbatches->lru_deactivate_file) ||
folio_batch_count(&fbatches->lru_deactivate) ||
folio_batch_count(&fbatches->lru_lazyfree) ||
folio_batch_count(&fbatches->activate) ||
need_mlock_drain(cpu) ||
has_bh_in_lru(cpu, NULL);
}
/*
* Doesn't need any cpu hotplug locking because we do rely on per-cpu
* kworkers being shut down before our page_alloc_cpu_dead callback is
* executed on the offlined cpu.
* Calling this function with cpu hotplug locks held can actually lead
* to obscure indirect dependencies via WQ context.
*/
static inline void __lru_add_drain_all(bool force_all_cpus)
{
/*
* lru_drain_gen - Global pages generation number
*
* (A) Definition: global lru_drain_gen = x implies that all generations
* 0 < n <= x are already *scheduled* for draining.
*
* This is an optimization for the highly-contended use case where a
* user space workload keeps constantly generating a flow of pages for
* each CPU.
*/
static unsigned int lru_drain_gen;
static struct cpumask has_work;
static DEFINE_MUTEX(lock);
unsigned cpu, this_gen;
/*
* Make sure nobody triggers this path before mm_percpu_wq is fully
* initialized.
*/
if (WARN_ON(!mm_percpu_wq))
return;
/*
* Guarantee folio_batch counter stores visible by this CPU
* are visible to other CPUs before loading the current drain
* generation.
*/
smp_mb();
/*
* (B) Locally cache global LRU draining generation number
*
* The read barrier ensures that the counter is loaded before the mutex
* is taken. It pairs with smp_mb() inside the mutex critical section
* at (D).
*/
this_gen = smp_load_acquire(&lru_drain_gen);
mutex_lock(&lock);
/*
* (C) Exit the draining operation if a newer generation, from another
* lru_add_drain_all(), was already scheduled for draining. Check (A).
*/
if (unlikely(this_gen != lru_drain_gen && !force_all_cpus))
goto done;
/*
* (D) Increment global generation number
*
* Pairs with smp_load_acquire() at (B), outside of the critical
* section. Use a full memory barrier to guarantee that the
* new global drain generation number is stored before loading
* folio_batch counters.
*
* This pairing must be done here, before the for_each_online_cpu loop
* below which drains the page vectors.
*
* Let x, y, and z represent some system CPU numbers, where x < y < z.
* Assume CPU #z is in the middle of the for_each_online_cpu loop
* below and has already reached CPU #y's per-cpu data. CPU #x comes
* along, adds some pages to its per-cpu vectors, then calls
* lru_add_drain_all().
*
* If the paired barrier is done at any later step, e.g. after the
* loop, CPU #x will just exit at (C) and miss flushing out all of its
* added pages.
*/
WRITE_ONCE(lru_drain_gen, lru_drain_gen + 1);
smp_mb();
cpumask_clear(&has_work);
for_each_online_cpu(cpu) {
struct work_struct *work = &per_cpu(lru_add_drain_work, cpu);
if (cpu_needs_drain(cpu)) {
INIT_WORK(work, lru_add_drain_per_cpu);
queue_work_on(cpu, mm_percpu_wq, work);
__cpumask_set_cpu(cpu, &has_work);
}
}
for_each_cpu(cpu, &has_work)
flush_work(&per_cpu(lru_add_drain_work, cpu));
done:
mutex_unlock(&lock);
}
void lru_add_drain_all(void)
{
__lru_add_drain_all(false);
}
#else
void lru_add_drain_all(void)
{
lru_add_drain();
}
#endif /* CONFIG_SMP */
atomic_t lru_disable_count = ATOMIC_INIT(0);
/*
* lru_cache_disable() needs to be called before we start compiling
* a list of pages to be migrated using isolate_lru_page().
* It drains pages on LRU cache and then disable on all cpus until
* lru_cache_enable is called.
*
* Must be paired with a call to lru_cache_enable().
*/
void lru_cache_disable(void)
{
atomic_inc(&lru_disable_count);
/*
* Readers of lru_disable_count are protected by either disabling
* preemption or rcu_read_lock:
*
* preempt_disable, local_irq_disable [bh_lru_lock()]
* rcu_read_lock [rt_spin_lock CONFIG_PREEMPT_RT]
* preempt_disable [local_lock !CONFIG_PREEMPT_RT]
*
* Since v5.1 kernel, synchronize_rcu() is guaranteed to wait on
* preempt_disable() regions of code. So any CPU which sees
* lru_disable_count = 0 will have exited the critical
* section when synchronize_rcu() returns.
*/
synchronize_rcu_expedited();
#ifdef CONFIG_SMP
__lru_add_drain_all(true);
#else
lru_add_and_bh_lrus_drain();
#endif
}
/**
* release_pages - batched put_page()
* @arg: array of pages to release
* @nr: number of pages
*
* Decrement the reference count on all the pages in @arg. If it
* fell to zero, remove the page from the LRU and free it.
*
* Note that the argument can be an array of pages, encoded pages,
* or folio pointers. We ignore any encoded bits, and turn any of
* them into just a folio that gets free'd.
*/
void release_pages(release_pages_arg arg, int nr)
{
int i;
struct encoded_page **encoded = arg.encoded_pages;
LIST_HEAD(pages_to_free);
struct lruvec *lruvec = NULL;
unsigned long flags = 0;
unsigned int lock_batch;
for (i = 0; i < nr; i++) {
struct folio *folio;
/* Turn any of the argument types into a folio */
folio = page_folio(encoded_page_ptr(encoded[i]));
/*
* Make sure the IRQ-safe lock-holding time does not get
* excessive with a continuous string of pages from the
* same lruvec. The lock is held only if lruvec != NULL.
*/
if (lruvec && ++lock_batch == SWAP_CLUSTER_MAX) {
unlock_page_lruvec_irqrestore(lruvec, flags);
lruvec = NULL;
}
if (is_huge_zero_page(&folio->page))
continue;
if (folio_is_zone_device(folio)) {
if (lruvec) {
unlock_page_lruvec_irqrestore(lruvec, flags);
lruvec = NULL;
}
if (put_devmap_managed_page(&folio->page))
continue;
if (folio_put_testzero(folio))
free_zone_device_page(&folio->page);
continue;
}
if (!folio_put_testzero(folio))
continue;
if (folio_test_large(folio)) {
if (lruvec) {
unlock_page_lruvec_irqrestore(lruvec, flags);
lruvec = NULL;
}
__folio_put_large(folio);
continue;
}
if (folio_test_lru(folio)) {
struct lruvec *prev_lruvec = lruvec;
lruvec = folio_lruvec_relock_irqsave(folio, lruvec,
&flags);
if (prev_lruvec != lruvec)
lock_batch = 0;
lruvec_del_folio(lruvec, folio);
__folio_clear_lru_flags(folio);
}
/*
* In rare cases, when truncation or holepunching raced with
* munlock after VM_LOCKED was cleared, Mlocked may still be
* found set here. This does not indicate a problem, unless
* "unevictable_pgs_cleared" appears worryingly large.
*/
if (unlikely(folio_test_mlocked(folio))) {
__folio_clear_mlocked(folio);
zone_stat_sub_folio(folio, NR_MLOCK);
count_vm_event(UNEVICTABLE_PGCLEARED);
}
list_add(&folio->lru, &pages_to_free);
}
if (lruvec)
unlock_page_lruvec_irqrestore(lruvec, flags);
mem_cgroup_uncharge_list(&pages_to_free);
free_unref_page_list(&pages_to_free);
}
EXPORT_SYMBOL(release_pages);
/*
* The folios which we're about to release may be in the deferred lru-addition
* queues. That would prevent them from really being freed right now. That's
* OK from a correctness point of view but is inefficient - those folios may be
* cache-warm and we want to give them back to the page allocator ASAP.
*
* So __folio_batch_release() will drain those queues here.
* folio_batch_move_lru() calls folios_put() directly to avoid
* mutual recursion.
*/
void __folio_batch_release(struct folio_batch *fbatch)
{
if (!fbatch->percpu_pvec_drained) {
lru_add_drain();
fbatch->percpu_pvec_drained = true;
}
release_pages(fbatch->folios, folio_batch_count(fbatch));
folio_batch_reinit(fbatch);
}
EXPORT_SYMBOL(__folio_batch_release);
/**
* folio_batch_remove_exceptionals() - Prune non-folios from a batch.
* @fbatch: The batch to prune
*
* find_get_entries() fills a batch with both folios and shadow/swap/DAX
* entries. This function prunes all the non-folio entries from @fbatch
* without leaving holes, so that it can be passed on to folio-only batch
* operations.
*/
void folio_batch_remove_exceptionals(struct folio_batch *fbatch)
{
unsigned int i, j;
for (i = 0, j = 0; i < folio_batch_count(fbatch); i++) {
struct folio *folio = fbatch->folios[i];
if (!xa_is_value(folio))
fbatch->folios[j++] = folio;
}
fbatch->nr = j;
}
/*
* Perform any setup for the swap system
*/
void __init swap_setup(void)
{
unsigned long megs = totalram_pages() >> (20 - PAGE_SHIFT);
/* Use a smaller cluster for small-memory machines */
if (megs < 16)
page_cluster = 2;
else
page_cluster = 3;
/*
* Right now other parts of the system means that we
* _really_ don't want to cluster much more
*/
}
| linux-master | mm/swap.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* DMA Pool allocator
*
* Copyright 2001 David Brownell
* Copyright 2007 Intel Corporation
* Author: Matthew Wilcox <[email protected]>
*
* This allocator returns small blocks of a given size which are DMA-able by
* the given device. It uses the dma_alloc_coherent page allocator to get
* new pages, then splits them up into blocks of the required size.
* Many older drivers still have their own code to do this.
*
* The current design of this allocator is fairly simple. The pool is
* represented by the 'struct dma_pool' which keeps a doubly-linked list of
* allocated pages. Each page in the page_list is split into blocks of at
* least 'size' bytes. Free blocks are tracked in an unsorted singly-linked
* list of free blocks across all pages. Used blocks aren't tracked, but we
* keep a count of how many are currently allocated from each page.
*/
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/dmapool.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/export.h>
#include <linux/mutex.h>
#include <linux/poison.h>
#include <linux/sched.h>
#include <linux/sched/mm.h>
#include <linux/slab.h>
#include <linux/stat.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/wait.h>
#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB_DEBUG_ON)
#define DMAPOOL_DEBUG 1
#endif
struct dma_block {
struct dma_block *next_block;
dma_addr_t dma;
};
struct dma_pool { /* the pool */
struct list_head page_list;
spinlock_t lock;
struct dma_block *next_block;
size_t nr_blocks;
size_t nr_active;
size_t nr_pages;
struct device *dev;
unsigned int size;
unsigned int allocation;
unsigned int boundary;
char name[32];
struct list_head pools;
};
struct dma_page { /* cacheable header for 'allocation' bytes */
struct list_head page_list;
void *vaddr;
dma_addr_t dma;
};
static DEFINE_MUTEX(pools_lock);
static DEFINE_MUTEX(pools_reg_lock);
static ssize_t pools_show(struct device *dev, struct device_attribute *attr, char *buf)
{
struct dma_pool *pool;
unsigned size;
size = sysfs_emit(buf, "poolinfo - 0.1\n");
mutex_lock(&pools_lock);
list_for_each_entry(pool, &dev->dma_pools, pools) {
/* per-pool info, no real statistics yet */
size += sysfs_emit_at(buf, size, "%-16s %4zu %4zu %4u %2zu\n",
pool->name, pool->nr_active,
pool->nr_blocks, pool->size,
pool->nr_pages);
}
mutex_unlock(&pools_lock);
return size;
}
static DEVICE_ATTR_RO(pools);
#ifdef DMAPOOL_DEBUG
static void pool_check_block(struct dma_pool *pool, struct dma_block *block,
gfp_t mem_flags)
{
u8 *data = (void *)block;
int i;
for (i = sizeof(struct dma_block); i < pool->size; i++) {
if (data[i] == POOL_POISON_FREED)
continue;
dev_err(pool->dev, "%s %s, %p (corrupted)\n", __func__,
pool->name, block);
/*
* Dump the first 4 bytes even if they are not
* POOL_POISON_FREED
*/
print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1,
data, pool->size, 1);
break;
}
if (!want_init_on_alloc(mem_flags))
memset(block, POOL_POISON_ALLOCATED, pool->size);
}
static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma)
{
struct dma_page *page;
list_for_each_entry(page, &pool->page_list, page_list) {
if (dma < page->dma)
continue;
if ((dma - page->dma) < pool->allocation)
return page;
}
return NULL;
}
static bool pool_block_err(struct dma_pool *pool, void *vaddr, dma_addr_t dma)
{
struct dma_block *block = pool->next_block;
struct dma_page *page;
page = pool_find_page(pool, dma);
if (!page) {
dev_err(pool->dev, "%s %s, %p/%pad (bad dma)\n",
__func__, pool->name, vaddr, &dma);
return true;
}
while (block) {
if (block != vaddr) {
block = block->next_block;
continue;
}
dev_err(pool->dev, "%s %s, dma %pad already free\n",
__func__, pool->name, &dma);
return true;
}
memset(vaddr, POOL_POISON_FREED, pool->size);
return false;
}
static void pool_init_page(struct dma_pool *pool, struct dma_page *page)
{
memset(page->vaddr, POOL_POISON_FREED, pool->allocation);
}
#else
static void pool_check_block(struct dma_pool *pool, struct dma_block *block,
gfp_t mem_flags)
{
}
static bool pool_block_err(struct dma_pool *pool, void *vaddr, dma_addr_t dma)
{
if (want_init_on_free())
memset(vaddr, 0, pool->size);
return false;
}
static void pool_init_page(struct dma_pool *pool, struct dma_page *page)
{
}
#endif
static struct dma_block *pool_block_pop(struct dma_pool *pool)
{
struct dma_block *block = pool->next_block;
if (block) {
pool->next_block = block->next_block;
pool->nr_active++;
}
return block;
}
static void pool_block_push(struct dma_pool *pool, struct dma_block *block,
dma_addr_t dma)
{
block->dma = dma;
block->next_block = pool->next_block;
pool->next_block = block;
}
/**
* dma_pool_create - Creates a pool of consistent memory blocks, for dma.
* @name: name of pool, for diagnostics
* @dev: device that will be doing the DMA
* @size: size of the blocks in this pool.
* @align: alignment requirement for blocks; must be a power of two
* @boundary: returned blocks won't cross this power of two boundary
* Context: not in_interrupt()
*
* Given one of these pools, dma_pool_alloc()
* may be used to allocate memory. Such memory will all have "consistent"
* DMA mappings, accessible by the device and its driver without using
* cache flushing primitives. The actual size of blocks allocated may be
* larger than requested because of alignment.
*
* If @boundary is nonzero, objects returned from dma_pool_alloc() won't
* cross that size boundary. This is useful for devices which have
* addressing restrictions on individual DMA transfers, such as not crossing
* boundaries of 4KBytes.
*
* Return: a dma allocation pool with the requested characteristics, or
* %NULL if one can't be created.
*/
struct dma_pool *dma_pool_create(const char *name, struct device *dev,
size_t size, size_t align, size_t boundary)
{
struct dma_pool *retval;
size_t allocation;
bool empty;
if (!dev)
return NULL;
if (align == 0)
align = 1;
else if (align & (align - 1))
return NULL;
if (size == 0 || size > INT_MAX)
return NULL;
if (size < sizeof(struct dma_block))
size = sizeof(struct dma_block);
size = ALIGN(size, align);
allocation = max_t(size_t, size, PAGE_SIZE);
if (!boundary)
boundary = allocation;
else if ((boundary < size) || (boundary & (boundary - 1)))
return NULL;
boundary = min(boundary, allocation);
retval = kzalloc(sizeof(*retval), GFP_KERNEL);
if (!retval)
return retval;
strscpy(retval->name, name, sizeof(retval->name));
retval->dev = dev;
INIT_LIST_HEAD(&retval->page_list);
spin_lock_init(&retval->lock);
retval->size = size;
retval->boundary = boundary;
retval->allocation = allocation;
INIT_LIST_HEAD(&retval->pools);
/*
* pools_lock ensures that the ->dma_pools list does not get corrupted.
* pools_reg_lock ensures that there is not a race between
* dma_pool_create() and dma_pool_destroy() or within dma_pool_create()
* when the first invocation of dma_pool_create() failed on
* device_create_file() and the second assumes that it has been done (I
* know it is a short window).
*/
mutex_lock(&pools_reg_lock);
mutex_lock(&pools_lock);
empty = list_empty(&dev->dma_pools);
list_add(&retval->pools, &dev->dma_pools);
mutex_unlock(&pools_lock);
if (empty) {
int err;
err = device_create_file(dev, &dev_attr_pools);
if (err) {
mutex_lock(&pools_lock);
list_del(&retval->pools);
mutex_unlock(&pools_lock);
mutex_unlock(&pools_reg_lock);
kfree(retval);
return NULL;
}
}
mutex_unlock(&pools_reg_lock);
return retval;
}
EXPORT_SYMBOL(dma_pool_create);
static void pool_initialise_page(struct dma_pool *pool, struct dma_page *page)
{
unsigned int next_boundary = pool->boundary, offset = 0;
struct dma_block *block, *first = NULL, *last = NULL;
pool_init_page(pool, page);
while (offset + pool->size <= pool->allocation) {
if (offset + pool->size > next_boundary) {
offset = next_boundary;
next_boundary += pool->boundary;
continue;
}
block = page->vaddr + offset;
block->dma = page->dma + offset;
block->next_block = NULL;
if (last)
last->next_block = block;
else
first = block;
last = block;
offset += pool->size;
pool->nr_blocks++;
}
last->next_block = pool->next_block;
pool->next_block = first;
list_add(&page->page_list, &pool->page_list);
pool->nr_pages++;
}
static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags)
{
struct dma_page *page;
page = kmalloc(sizeof(*page), mem_flags);
if (!page)
return NULL;
page->vaddr = dma_alloc_coherent(pool->dev, pool->allocation,
&page->dma, mem_flags);
if (!page->vaddr) {
kfree(page);
return NULL;
}
return page;
}
/**
* dma_pool_destroy - destroys a pool of dma memory blocks.
* @pool: dma pool that will be destroyed
* Context: !in_interrupt()
*
* Caller guarantees that no more memory from the pool is in use,
* and that nothing will try to use the pool after this call.
*/
void dma_pool_destroy(struct dma_pool *pool)
{
struct dma_page *page, *tmp;
bool empty, busy = false;
if (unlikely(!pool))
return;
mutex_lock(&pools_reg_lock);
mutex_lock(&pools_lock);
list_del(&pool->pools);
empty = list_empty(&pool->dev->dma_pools);
mutex_unlock(&pools_lock);
if (empty)
device_remove_file(pool->dev, &dev_attr_pools);
mutex_unlock(&pools_reg_lock);
if (pool->nr_active) {
dev_err(pool->dev, "%s %s busy\n", __func__, pool->name);
busy = true;
}
list_for_each_entry_safe(page, tmp, &pool->page_list, page_list) {
if (!busy)
dma_free_coherent(pool->dev, pool->allocation,
page->vaddr, page->dma);
list_del(&page->page_list);
kfree(page);
}
kfree(pool);
}
EXPORT_SYMBOL(dma_pool_destroy);
/**
* dma_pool_alloc - get a block of consistent memory
* @pool: dma pool that will produce the block
* @mem_flags: GFP_* bitmask
* @handle: pointer to dma address of block
*
* Return: the kernel virtual address of a currently unused block,
* and reports its dma address through the handle.
* If such a memory block can't be allocated, %NULL is returned.
*/
void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags,
dma_addr_t *handle)
{
struct dma_block *block;
struct dma_page *page;
unsigned long flags;
might_alloc(mem_flags);
spin_lock_irqsave(&pool->lock, flags);
block = pool_block_pop(pool);
if (!block) {
/*
* pool_alloc_page() might sleep, so temporarily drop
* &pool->lock
*/
spin_unlock_irqrestore(&pool->lock, flags);
page = pool_alloc_page(pool, mem_flags & (~__GFP_ZERO));
if (!page)
return NULL;
spin_lock_irqsave(&pool->lock, flags);
pool_initialise_page(pool, page);
block = pool_block_pop(pool);
}
spin_unlock_irqrestore(&pool->lock, flags);
*handle = block->dma;
pool_check_block(pool, block, mem_flags);
if (want_init_on_alloc(mem_flags))
memset(block, 0, pool->size);
return block;
}
EXPORT_SYMBOL(dma_pool_alloc);
/**
* dma_pool_free - put block back into dma pool
* @pool: the dma pool holding the block
* @vaddr: virtual address of block
* @dma: dma address of block
*
* Caller promises neither device nor driver will again touch this block
* unless it is first re-allocated.
*/
void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma)
{
struct dma_block *block = vaddr;
unsigned long flags;
spin_lock_irqsave(&pool->lock, flags);
if (!pool_block_err(pool, vaddr, dma)) {
pool_block_push(pool, block, dma);
pool->nr_active--;
}
spin_unlock_irqrestore(&pool->lock, flags);
}
EXPORT_SYMBOL(dma_pool_free);
/*
* Managed DMA pool
*/
static void dmam_pool_release(struct device *dev, void *res)
{
struct dma_pool *pool = *(struct dma_pool **)res;
dma_pool_destroy(pool);
}
static int dmam_pool_match(struct device *dev, void *res, void *match_data)
{
return *(struct dma_pool **)res == match_data;
}
/**
* dmam_pool_create - Managed dma_pool_create()
* @name: name of pool, for diagnostics
* @dev: device that will be doing the DMA
* @size: size of the blocks in this pool.
* @align: alignment requirement for blocks; must be a power of two
* @allocation: returned blocks won't cross this boundary (or zero)
*
* Managed dma_pool_create(). DMA pool created with this function is
* automatically destroyed on driver detach.
*
* Return: a managed dma allocation pool with the requested
* characteristics, or %NULL if one can't be created.
*/
struct dma_pool *dmam_pool_create(const char *name, struct device *dev,
size_t size, size_t align, size_t allocation)
{
struct dma_pool **ptr, *pool;
ptr = devres_alloc(dmam_pool_release, sizeof(*ptr), GFP_KERNEL);
if (!ptr)
return NULL;
pool = *ptr = dma_pool_create(name, dev, size, align, allocation);
if (pool)
devres_add(dev, ptr);
else
devres_free(ptr);
return pool;
}
EXPORT_SYMBOL(dmam_pool_create);
/**
* dmam_pool_destroy - Managed dma_pool_destroy()
* @pool: dma pool that will be destroyed
*
* Managed dma_pool_destroy().
*/
void dmam_pool_destroy(struct dma_pool *pool)
{
struct device *dev = pool->dev;
WARN_ON(devres_release(dev, dmam_pool_release, dmam_pool_match, pool));
}
EXPORT_SYMBOL(dmam_pool_destroy);
| linux-master | mm/dmapool.c |
// SPDX-License-Identifier: GPL-2.0
/*
* mm/mprotect.c
*
* (C) Copyright 1994 Linus Torvalds
* (C) Copyright 2002 Christoph Hellwig
*
* Address space accounting code <[email protected]>
* (C) Copyright 2002 Red Hat Inc, All Rights Reserved
*/
#include <linux/pagewalk.h>
#include <linux/hugetlb.h>
#include <linux/shm.h>
#include <linux/mman.h>
#include <linux/fs.h>
#include <linux/highmem.h>
#include <linux/security.h>
#include <linux/mempolicy.h>
#include <linux/personality.h>
#include <linux/syscalls.h>
#include <linux/swap.h>
#include <linux/swapops.h>
#include <linux/mmu_notifier.h>
#include <linux/migrate.h>
#include <linux/perf_event.h>
#include <linux/pkeys.h>
#include <linux/ksm.h>
#include <linux/uaccess.h>
#include <linux/mm_inline.h>
#include <linux/pgtable.h>
#include <linux/sched/sysctl.h>
#include <linux/userfaultfd_k.h>
#include <linux/memory-tiers.h>
#include <asm/cacheflush.h>
#include <asm/mmu_context.h>
#include <asm/tlbflush.h>
#include <asm/tlb.h>
#include "internal.h"
bool can_change_pte_writable(struct vm_area_struct *vma, unsigned long addr,
pte_t pte)
{
struct page *page;
if (WARN_ON_ONCE(!(vma->vm_flags & VM_WRITE)))
return false;
/* Don't touch entries that are not even readable. */
if (pte_protnone(pte))
return false;
/* Do we need write faults for softdirty tracking? */
if (vma_soft_dirty_enabled(vma) && !pte_soft_dirty(pte))
return false;
/* Do we need write faults for uffd-wp tracking? */
if (userfaultfd_pte_wp(vma, pte))
return false;
if (!(vma->vm_flags & VM_SHARED)) {
/*
* Writable MAP_PRIVATE mapping: We can only special-case on
* exclusive anonymous pages, because we know that our
* write-fault handler similarly would map them writable without
* any additional checks while holding the PT lock.
*/
page = vm_normal_page(vma, addr, pte);
return page && PageAnon(page) && PageAnonExclusive(page);
}
/*
* Writable MAP_SHARED mapping: "clean" might indicate that the FS still
* needs a real write-fault for writenotify
* (see vma_wants_writenotify()). If "dirty", the assumption is that the
* FS was already notified and we can simply mark the PTE writable
* just like the write-fault handler would do.
*/
return pte_dirty(pte);
}
static long change_pte_range(struct mmu_gather *tlb,
struct vm_area_struct *vma, pmd_t *pmd, unsigned long addr,
unsigned long end, pgprot_t newprot, unsigned long cp_flags)
{
pte_t *pte, oldpte;
spinlock_t *ptl;
long pages = 0;
int target_node = NUMA_NO_NODE;
bool prot_numa = cp_flags & MM_CP_PROT_NUMA;
bool uffd_wp = cp_flags & MM_CP_UFFD_WP;
bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE;
tlb_change_page_size(tlb, PAGE_SIZE);
pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
if (!pte)
return -EAGAIN;
/* Get target node for single threaded private VMAs */
if (prot_numa && !(vma->vm_flags & VM_SHARED) &&
atomic_read(&vma->vm_mm->mm_users) == 1)
target_node = numa_node_id();
flush_tlb_batched_pending(vma->vm_mm);
arch_enter_lazy_mmu_mode();
do {
oldpte = ptep_get(pte);
if (pte_present(oldpte)) {
pte_t ptent;
/*
* Avoid trapping faults against the zero or KSM
* pages. See similar comment in change_huge_pmd.
*/
if (prot_numa) {
struct page *page;
int nid;
bool toptier;
/* Avoid TLB flush if possible */
if (pte_protnone(oldpte))
continue;
page = vm_normal_page(vma, addr, oldpte);
if (!page || is_zone_device_page(page) || PageKsm(page))
continue;
/* Also skip shared copy-on-write pages */
if (is_cow_mapping(vma->vm_flags) &&
page_count(page) != 1)
continue;
/*
* While migration can move some dirty pages,
* it cannot move them all from MIGRATE_ASYNC
* context.
*/
if (page_is_file_lru(page) && PageDirty(page))
continue;
/*
* Don't mess with PTEs if page is already on the node
* a single-threaded process is running on.
*/
nid = page_to_nid(page);
if (target_node == nid)
continue;
toptier = node_is_toptier(nid);
/*
* Skip scanning top tier node if normal numa
* balancing is disabled
*/
if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_NORMAL) &&
toptier)
continue;
if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING &&
!toptier)
xchg_page_access_time(page,
jiffies_to_msecs(jiffies));
}
oldpte = ptep_modify_prot_start(vma, addr, pte);
ptent = pte_modify(oldpte, newprot);
if (uffd_wp)
ptent = pte_mkuffd_wp(ptent);
else if (uffd_wp_resolve)
ptent = pte_clear_uffd_wp(ptent);
/*
* In some writable, shared mappings, we might want
* to catch actual write access -- see
* vma_wants_writenotify().
*
* In all writable, private mappings, we have to
* properly handle COW.
*
* In both cases, we can sometimes still change PTEs
* writable and avoid the write-fault handler, for
* example, if a PTE is already dirty and no other
* COW or special handling is required.
*/
if ((cp_flags & MM_CP_TRY_CHANGE_WRITABLE) &&
!pte_write(ptent) &&
can_change_pte_writable(vma, addr, ptent))
ptent = pte_mkwrite(ptent, vma);
ptep_modify_prot_commit(vma, addr, pte, oldpte, ptent);
if (pte_needs_flush(oldpte, ptent))
tlb_flush_pte_range(tlb, addr, PAGE_SIZE);
pages++;
} else if (is_swap_pte(oldpte)) {
swp_entry_t entry = pte_to_swp_entry(oldpte);
pte_t newpte;
if (is_writable_migration_entry(entry)) {
struct page *page = pfn_swap_entry_to_page(entry);
/*
* A protection check is difficult so
* just be safe and disable write
*/
if (PageAnon(page))
entry = make_readable_exclusive_migration_entry(
swp_offset(entry));
else
entry = make_readable_migration_entry(swp_offset(entry));
newpte = swp_entry_to_pte(entry);
if (pte_swp_soft_dirty(oldpte))
newpte = pte_swp_mksoft_dirty(newpte);
} else if (is_writable_device_private_entry(entry)) {
/*
* We do not preserve soft-dirtiness. See
* copy_nonpresent_pte() for explanation.
*/
entry = make_readable_device_private_entry(
swp_offset(entry));
newpte = swp_entry_to_pte(entry);
if (pte_swp_uffd_wp(oldpte))
newpte = pte_swp_mkuffd_wp(newpte);
} else if (is_writable_device_exclusive_entry(entry)) {
entry = make_readable_device_exclusive_entry(
swp_offset(entry));
newpte = swp_entry_to_pte(entry);
if (pte_swp_soft_dirty(oldpte))
newpte = pte_swp_mksoft_dirty(newpte);
if (pte_swp_uffd_wp(oldpte))
newpte = pte_swp_mkuffd_wp(newpte);
} else if (is_pte_marker_entry(entry)) {
/*
* Ignore error swap entries unconditionally,
* because any access should sigbus anyway.
*/
if (is_poisoned_swp_entry(entry))
continue;
/*
* If this is uffd-wp pte marker and we'd like
* to unprotect it, drop it; the next page
* fault will trigger without uffd trapping.
*/
if (uffd_wp_resolve) {
pte_clear(vma->vm_mm, addr, pte);
pages++;
}
continue;
} else {
newpte = oldpte;
}
if (uffd_wp)
newpte = pte_swp_mkuffd_wp(newpte);
else if (uffd_wp_resolve)
newpte = pte_swp_clear_uffd_wp(newpte);
if (!pte_same(oldpte, newpte)) {
set_pte_at(vma->vm_mm, addr, pte, newpte);
pages++;
}
} else {
/* It must be an none page, or what else?.. */
WARN_ON_ONCE(!pte_none(oldpte));
/*
* Nobody plays with any none ptes besides
* userfaultfd when applying the protections.
*/
if (likely(!uffd_wp))
continue;
if (userfaultfd_wp_use_markers(vma)) {
/*
* For file-backed mem, we need to be able to
* wr-protect a none pte, because even if the
* pte is none, the page/swap cache could
* exist. Doing that by install a marker.
*/
set_pte_at(vma->vm_mm, addr, pte,
make_pte_marker(PTE_MARKER_UFFD_WP));
pages++;
}
}
} while (pte++, addr += PAGE_SIZE, addr != end);
arch_leave_lazy_mmu_mode();
pte_unmap_unlock(pte - 1, ptl);
return pages;
}
/*
* Return true if we want to split THPs into PTE mappings in change
* protection procedure, false otherwise.
*/
static inline bool
pgtable_split_needed(struct vm_area_struct *vma, unsigned long cp_flags)
{
/*
* pte markers only resides in pte level, if we need pte markers,
* we need to split. We cannot wr-protect shmem thp because file
* thp is handled differently when split by erasing the pmd so far.
*/
return (cp_flags & MM_CP_UFFD_WP) && !vma_is_anonymous(vma);
}
/*
* Return true if we want to populate pgtables in change protection
* procedure, false otherwise
*/
static inline bool
pgtable_populate_needed(struct vm_area_struct *vma, unsigned long cp_flags)
{
/* If not within ioctl(UFFDIO_WRITEPROTECT), then don't bother */
if (!(cp_flags & MM_CP_UFFD_WP))
return false;
/* Populate if the userfaultfd mode requires pte markers */
return userfaultfd_wp_use_markers(vma);
}
/*
* Populate the pgtable underneath for whatever reason if requested.
* When {pte|pmd|...}_alloc() failed we treat it the same way as pgtable
* allocation failures during page faults by kicking OOM and returning
* error.
*/
#define change_pmd_prepare(vma, pmd, cp_flags) \
({ \
long err = 0; \
if (unlikely(pgtable_populate_needed(vma, cp_flags))) { \
if (pte_alloc(vma->vm_mm, pmd)) \
err = -ENOMEM; \
} \
err; \
})
/*
* This is the general pud/p4d/pgd version of change_pmd_prepare(). We need to
* have separate change_pmd_prepare() because pte_alloc() returns 0 on success,
* while {pmd|pud|p4d}_alloc() returns the valid pointer on success.
*/
#define change_prepare(vma, high, low, addr, cp_flags) \
({ \
long err = 0; \
if (unlikely(pgtable_populate_needed(vma, cp_flags))) { \
low##_t *p = low##_alloc(vma->vm_mm, high, addr); \
if (p == NULL) \
err = -ENOMEM; \
} \
err; \
})
static inline long change_pmd_range(struct mmu_gather *tlb,
struct vm_area_struct *vma, pud_t *pud, unsigned long addr,
unsigned long end, pgprot_t newprot, unsigned long cp_flags)
{
pmd_t *pmd;
unsigned long next;
long pages = 0;
unsigned long nr_huge_updates = 0;
struct mmu_notifier_range range;
range.start = 0;
pmd = pmd_offset(pud, addr);
do {
long ret;
pmd_t _pmd;
again:
next = pmd_addr_end(addr, end);
ret = change_pmd_prepare(vma, pmd, cp_flags);
if (ret) {
pages = ret;
break;
}
if (pmd_none(*pmd))
goto next;
/* invoke the mmu notifier if the pmd is populated */
if (!range.start) {
mmu_notifier_range_init(&range,
MMU_NOTIFY_PROTECTION_VMA, 0,
vma->vm_mm, addr, end);
mmu_notifier_invalidate_range_start(&range);
}
_pmd = pmdp_get_lockless(pmd);
if (is_swap_pmd(_pmd) || pmd_trans_huge(_pmd) || pmd_devmap(_pmd)) {
if ((next - addr != HPAGE_PMD_SIZE) ||
pgtable_split_needed(vma, cp_flags)) {
__split_huge_pmd(vma, pmd, addr, false, NULL);
/*
* For file-backed, the pmd could have been
* cleared; make sure pmd populated if
* necessary, then fall-through to pte level.
*/
ret = change_pmd_prepare(vma, pmd, cp_flags);
if (ret) {
pages = ret;
break;
}
} else {
ret = change_huge_pmd(tlb, vma, pmd,
addr, newprot, cp_flags);
if (ret) {
if (ret == HPAGE_PMD_NR) {
pages += HPAGE_PMD_NR;
nr_huge_updates++;
}
/* huge pmd was handled */
goto next;
}
}
/* fall through, the trans huge pmd just split */
}
ret = change_pte_range(tlb, vma, pmd, addr, next, newprot,
cp_flags);
if (ret < 0)
goto again;
pages += ret;
next:
cond_resched();
} while (pmd++, addr = next, addr != end);
if (range.start)
mmu_notifier_invalidate_range_end(&range);
if (nr_huge_updates)
count_vm_numa_events(NUMA_HUGE_PTE_UPDATES, nr_huge_updates);
return pages;
}
static inline long change_pud_range(struct mmu_gather *tlb,
struct vm_area_struct *vma, p4d_t *p4d, unsigned long addr,
unsigned long end, pgprot_t newprot, unsigned long cp_flags)
{
pud_t *pud;
unsigned long next;
long pages = 0, ret;
pud = pud_offset(p4d, addr);
do {
next = pud_addr_end(addr, end);
ret = change_prepare(vma, pud, pmd, addr, cp_flags);
if (ret)
return ret;
if (pud_none_or_clear_bad(pud))
continue;
pages += change_pmd_range(tlb, vma, pud, addr, next, newprot,
cp_flags);
} while (pud++, addr = next, addr != end);
return pages;
}
static inline long change_p4d_range(struct mmu_gather *tlb,
struct vm_area_struct *vma, pgd_t *pgd, unsigned long addr,
unsigned long end, pgprot_t newprot, unsigned long cp_flags)
{
p4d_t *p4d;
unsigned long next;
long pages = 0, ret;
p4d = p4d_offset(pgd, addr);
do {
next = p4d_addr_end(addr, end);
ret = change_prepare(vma, p4d, pud, addr, cp_flags);
if (ret)
return ret;
if (p4d_none_or_clear_bad(p4d))
continue;
pages += change_pud_range(tlb, vma, p4d, addr, next, newprot,
cp_flags);
} while (p4d++, addr = next, addr != end);
return pages;
}
static long change_protection_range(struct mmu_gather *tlb,
struct vm_area_struct *vma, unsigned long addr,
unsigned long end, pgprot_t newprot, unsigned long cp_flags)
{
struct mm_struct *mm = vma->vm_mm;
pgd_t *pgd;
unsigned long next;
long pages = 0, ret;
BUG_ON(addr >= end);
pgd = pgd_offset(mm, addr);
tlb_start_vma(tlb, vma);
do {
next = pgd_addr_end(addr, end);
ret = change_prepare(vma, pgd, p4d, addr, cp_flags);
if (ret) {
pages = ret;
break;
}
if (pgd_none_or_clear_bad(pgd))
continue;
pages += change_p4d_range(tlb, vma, pgd, addr, next, newprot,
cp_flags);
} while (pgd++, addr = next, addr != end);
tlb_end_vma(tlb, vma);
return pages;
}
long change_protection(struct mmu_gather *tlb,
struct vm_area_struct *vma, unsigned long start,
unsigned long end, unsigned long cp_flags)
{
pgprot_t newprot = vma->vm_page_prot;
long pages;
BUG_ON((cp_flags & MM_CP_UFFD_WP_ALL) == MM_CP_UFFD_WP_ALL);
#ifdef CONFIG_NUMA_BALANCING
/*
* Ordinary protection updates (mprotect, uffd-wp, softdirty tracking)
* are expected to reflect their requirements via VMA flags such that
* vma_set_page_prot() will adjust vma->vm_page_prot accordingly.
*/
if (cp_flags & MM_CP_PROT_NUMA)
newprot = PAGE_NONE;
#else
WARN_ON_ONCE(cp_flags & MM_CP_PROT_NUMA);
#endif
if (is_vm_hugetlb_page(vma))
pages = hugetlb_change_protection(vma, start, end, newprot,
cp_flags);
else
pages = change_protection_range(tlb, vma, start, end, newprot,
cp_flags);
return pages;
}
static int prot_none_pte_entry(pte_t *pte, unsigned long addr,
unsigned long next, struct mm_walk *walk)
{
return pfn_modify_allowed(pte_pfn(ptep_get(pte)),
*(pgprot_t *)(walk->private)) ?
0 : -EACCES;
}
static int prot_none_hugetlb_entry(pte_t *pte, unsigned long hmask,
unsigned long addr, unsigned long next,
struct mm_walk *walk)
{
return pfn_modify_allowed(pte_pfn(ptep_get(pte)),
*(pgprot_t *)(walk->private)) ?
0 : -EACCES;
}
static int prot_none_test(unsigned long addr, unsigned long next,
struct mm_walk *walk)
{
return 0;
}
static const struct mm_walk_ops prot_none_walk_ops = {
.pte_entry = prot_none_pte_entry,
.hugetlb_entry = prot_none_hugetlb_entry,
.test_walk = prot_none_test,
.walk_lock = PGWALK_WRLOCK,
};
int
mprotect_fixup(struct vma_iterator *vmi, struct mmu_gather *tlb,
struct vm_area_struct *vma, struct vm_area_struct **pprev,
unsigned long start, unsigned long end, unsigned long newflags)
{
struct mm_struct *mm = vma->vm_mm;
unsigned long oldflags = vma->vm_flags;
long nrpages = (end - start) >> PAGE_SHIFT;
unsigned int mm_cp_flags = 0;
unsigned long charged = 0;
pgoff_t pgoff;
int error;
if (newflags == oldflags) {
*pprev = vma;
return 0;
}
/*
* Do PROT_NONE PFN permission checks here when we can still
* bail out without undoing a lot of state. This is a rather
* uncommon case, so doesn't need to be very optimized.
*/
if (arch_has_pfn_modify_check() &&
(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) &&
(newflags & VM_ACCESS_FLAGS) == 0) {
pgprot_t new_pgprot = vm_get_page_prot(newflags);
error = walk_page_range(current->mm, start, end,
&prot_none_walk_ops, &new_pgprot);
if (error)
return error;
}
/*
* If we make a private mapping writable we increase our commit;
* but (without finer accounting) cannot reduce our commit if we
* make it unwritable again. hugetlb mapping were accounted for
* even if read-only so there is no need to account for them here
*/
if (newflags & VM_WRITE) {
/* Check space limits when area turns into data. */
if (!may_expand_vm(mm, newflags, nrpages) &&
may_expand_vm(mm, oldflags, nrpages))
return -ENOMEM;
if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_HUGETLB|
VM_SHARED|VM_NORESERVE))) {
charged = nrpages;
if (security_vm_enough_memory_mm(mm, charged))
return -ENOMEM;
newflags |= VM_ACCOUNT;
}
}
/*
* First try to merge with previous and/or next vma.
*/
pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
*pprev = vma_merge(vmi, mm, *pprev, start, end, newflags,
vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma),
vma->vm_userfaultfd_ctx, anon_vma_name(vma));
if (*pprev) {
vma = *pprev;
VM_WARN_ON((vma->vm_flags ^ newflags) & ~VM_SOFTDIRTY);
goto success;
}
*pprev = vma;
if (start != vma->vm_start) {
error = split_vma(vmi, vma, start, 1);
if (error)
goto fail;
}
if (end != vma->vm_end) {
error = split_vma(vmi, vma, end, 0);
if (error)
goto fail;
}
success:
/*
* vm_flags and vm_page_prot are protected by the mmap_lock
* held in write mode.
*/
vma_start_write(vma);
vm_flags_reset(vma, newflags);
if (vma_wants_manual_pte_write_upgrade(vma))
mm_cp_flags |= MM_CP_TRY_CHANGE_WRITABLE;
vma_set_page_prot(vma);
change_protection(tlb, vma, start, end, mm_cp_flags);
/*
* Private VM_LOCKED VMA becoming writable: trigger COW to avoid major
* fault on access.
*/
if ((oldflags & (VM_WRITE | VM_SHARED | VM_LOCKED)) == VM_LOCKED &&
(newflags & VM_WRITE)) {
populate_vma_page_range(vma, start, end, NULL);
}
vm_stat_account(mm, oldflags, -nrpages);
vm_stat_account(mm, newflags, nrpages);
perf_event_mmap(vma);
return 0;
fail:
vm_unacct_memory(charged);
return error;
}
/*
* pkey==-1 when doing a legacy mprotect()
*/
static int do_mprotect_pkey(unsigned long start, size_t len,
unsigned long prot, int pkey)
{
unsigned long nstart, end, tmp, reqprot;
struct vm_area_struct *vma, *prev;
int error;
const int grows = prot & (PROT_GROWSDOWN|PROT_GROWSUP);
const bool rier = (current->personality & READ_IMPLIES_EXEC) &&
(prot & PROT_READ);
struct mmu_gather tlb;
struct vma_iterator vmi;
start = untagged_addr(start);
prot &= ~(PROT_GROWSDOWN|PROT_GROWSUP);
if (grows == (PROT_GROWSDOWN|PROT_GROWSUP)) /* can't be both */
return -EINVAL;
if (start & ~PAGE_MASK)
return -EINVAL;
if (!len)
return 0;
len = PAGE_ALIGN(len);
end = start + len;
if (end <= start)
return -ENOMEM;
if (!arch_validate_prot(prot, start))
return -EINVAL;
reqprot = prot;
if (mmap_write_lock_killable(current->mm))
return -EINTR;
/*
* If userspace did not allocate the pkey, do not let
* them use it here.
*/
error = -EINVAL;
if ((pkey != -1) && !mm_pkey_is_allocated(current->mm, pkey))
goto out;
vma_iter_init(&vmi, current->mm, start);
vma = vma_find(&vmi, end);
error = -ENOMEM;
if (!vma)
goto out;
if (unlikely(grows & PROT_GROWSDOWN)) {
if (vma->vm_start >= end)
goto out;
start = vma->vm_start;
error = -EINVAL;
if (!(vma->vm_flags & VM_GROWSDOWN))
goto out;
} else {
if (vma->vm_start > start)
goto out;
if (unlikely(grows & PROT_GROWSUP)) {
end = vma->vm_end;
error = -EINVAL;
if (!(vma->vm_flags & VM_GROWSUP))
goto out;
}
}
prev = vma_prev(&vmi);
if (start > vma->vm_start)
prev = vma;
tlb_gather_mmu(&tlb, current->mm);
nstart = start;
tmp = vma->vm_start;
for_each_vma_range(vmi, vma, end) {
unsigned long mask_off_old_flags;
unsigned long newflags;
int new_vma_pkey;
if (vma->vm_start != tmp) {
error = -ENOMEM;
break;
}
/* Does the application expect PROT_READ to imply PROT_EXEC */
if (rier && (vma->vm_flags & VM_MAYEXEC))
prot |= PROT_EXEC;
/*
* Each mprotect() call explicitly passes r/w/x permissions.
* If a permission is not passed to mprotect(), it must be
* cleared from the VMA.
*/
mask_off_old_flags = VM_ACCESS_FLAGS | VM_FLAGS_CLEAR;
new_vma_pkey = arch_override_mprotect_pkey(vma, prot, pkey);
newflags = calc_vm_prot_bits(prot, new_vma_pkey);
newflags |= (vma->vm_flags & ~mask_off_old_flags);
/* newflags >> 4 shift VM_MAY% in place of VM_% */
if ((newflags & ~(newflags >> 4)) & VM_ACCESS_FLAGS) {
error = -EACCES;
break;
}
if (map_deny_write_exec(vma, newflags)) {
error = -EACCES;
break;
}
/* Allow architectures to sanity-check the new flags */
if (!arch_validate_flags(newflags)) {
error = -EINVAL;
break;
}
error = security_file_mprotect(vma, reqprot, prot);
if (error)
break;
tmp = vma->vm_end;
if (tmp > end)
tmp = end;
if (vma->vm_ops && vma->vm_ops->mprotect) {
error = vma->vm_ops->mprotect(vma, nstart, tmp, newflags);
if (error)
break;
}
error = mprotect_fixup(&vmi, &tlb, vma, &prev, nstart, tmp, newflags);
if (error)
break;
tmp = vma_iter_end(&vmi);
nstart = tmp;
prot = reqprot;
}
tlb_finish_mmu(&tlb);
if (!error && tmp < end)
error = -ENOMEM;
out:
mmap_write_unlock(current->mm);
return error;
}
SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len,
unsigned long, prot)
{
return do_mprotect_pkey(start, len, prot, -1);
}
#ifdef CONFIG_ARCH_HAS_PKEYS
SYSCALL_DEFINE4(pkey_mprotect, unsigned long, start, size_t, len,
unsigned long, prot, int, pkey)
{
return do_mprotect_pkey(start, len, prot, pkey);
}
SYSCALL_DEFINE2(pkey_alloc, unsigned long, flags, unsigned long, init_val)
{
int pkey;
int ret;
/* No flags supported yet. */
if (flags)
return -EINVAL;
/* check for unsupported init values */
if (init_val & ~PKEY_ACCESS_MASK)
return -EINVAL;
mmap_write_lock(current->mm);
pkey = mm_pkey_alloc(current->mm);
ret = -ENOSPC;
if (pkey == -1)
goto out;
ret = arch_set_user_pkey_access(current, pkey, init_val);
if (ret) {
mm_pkey_free(current->mm, pkey);
goto out;
}
ret = pkey;
out:
mmap_write_unlock(current->mm);
return ret;
}
SYSCALL_DEFINE1(pkey_free, int, pkey)
{
int ret;
mmap_write_lock(current->mm);
ret = mm_pkey_free(current->mm, pkey);
mmap_write_unlock(current->mm);
/*
* We could provide warnings or errors if any VMA still
* has the pkey set here.
*/
return ret;
}
#endif /* CONFIG_ARCH_HAS_PKEYS */
| linux-master | mm/mprotect.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/mm/nommu.c
*
* Replacement code for mm functions to support CPU's that don't
* have any form of memory management unit (thus no virtual memory).
*
* See Documentation/admin-guide/mm/nommu-mmap.rst
*
* Copyright (c) 2004-2008 David Howells <[email protected]>
* Copyright (c) 2000-2003 David McCullough <[email protected]>
* Copyright (c) 2000-2001 D Jeff Dionne <[email protected]>
* Copyright (c) 2002 Greg Ungerer <[email protected]>
* Copyright (c) 2007-2010 Paul Mundt <[email protected]>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/export.h>
#include <linux/mm.h>
#include <linux/sched/mm.h>
#include <linux/mman.h>
#include <linux/swap.h>
#include <linux/file.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/backing-dev.h>
#include <linux/compiler.h>
#include <linux/mount.h>
#include <linux/personality.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/audit.h>
#include <linux/printk.h>
#include <linux/uaccess.h>
#include <linux/uio.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>
#include <asm/mmu_context.h>
#include "internal.h"
void *high_memory;
EXPORT_SYMBOL(high_memory);
struct page *mem_map;
unsigned long max_mapnr;
EXPORT_SYMBOL(max_mapnr);
unsigned long highest_memmap_pfn;
int sysctl_nr_trim_pages = CONFIG_NOMMU_INITIAL_TRIM_EXCESS;
int heap_stack_gap = 0;
atomic_long_t mmap_pages_allocated;
EXPORT_SYMBOL(mem_map);
/* list of mapped, potentially shareable regions */
static struct kmem_cache *vm_region_jar;
struct rb_root nommu_region_tree = RB_ROOT;
DECLARE_RWSEM(nommu_region_sem);
const struct vm_operations_struct generic_file_vm_ops = {
};
/*
* Return the total memory allocated for this pointer, not
* just what the caller asked for.
*
* Doesn't have to be accurate, i.e. may have races.
*/
unsigned int kobjsize(const void *objp)
{
struct page *page;
/*
* If the object we have should not have ksize performed on it,
* return size of 0
*/
if (!objp || !virt_addr_valid(objp))
return 0;
page = virt_to_head_page(objp);
/*
* If the allocator sets PageSlab, we know the pointer came from
* kmalloc().
*/
if (PageSlab(page))
return ksize(objp);
/*
* If it's not a compound page, see if we have a matching VMA
* region. This test is intentionally done in reverse order,
* so if there's no VMA, we still fall through and hand back
* PAGE_SIZE for 0-order pages.
*/
if (!PageCompound(page)) {
struct vm_area_struct *vma;
vma = find_vma(current->mm, (unsigned long)objp);
if (vma)
return vma->vm_end - vma->vm_start;
}
/*
* The ksize() function is only guaranteed to work for pointers
* returned by kmalloc(). So handle arbitrary pointers here.
*/
return page_size(page);
}
/**
* follow_pfn - look up PFN at a user virtual address
* @vma: memory mapping
* @address: user virtual address
* @pfn: location to store found PFN
*
* Only IO mappings and raw PFN mappings are allowed.
*
* Returns zero and the pfn at @pfn on success, -ve otherwise.
*/
int follow_pfn(struct vm_area_struct *vma, unsigned long address,
unsigned long *pfn)
{
if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
return -EINVAL;
*pfn = address >> PAGE_SHIFT;
return 0;
}
EXPORT_SYMBOL(follow_pfn);
LIST_HEAD(vmap_area_list);
void vfree(const void *addr)
{
kfree(addr);
}
EXPORT_SYMBOL(vfree);
void *__vmalloc(unsigned long size, gfp_t gfp_mask)
{
/*
* You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc()
* returns only a logical address.
*/
return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM);
}
EXPORT_SYMBOL(__vmalloc);
void *__vmalloc_node_range(unsigned long size, unsigned long align,
unsigned long start, unsigned long end, gfp_t gfp_mask,
pgprot_t prot, unsigned long vm_flags, int node,
const void *caller)
{
return __vmalloc(size, gfp_mask);
}
void *__vmalloc_node(unsigned long size, unsigned long align, gfp_t gfp_mask,
int node, const void *caller)
{
return __vmalloc(size, gfp_mask);
}
static void *__vmalloc_user_flags(unsigned long size, gfp_t flags)
{
void *ret;
ret = __vmalloc(size, flags);
if (ret) {
struct vm_area_struct *vma;
mmap_write_lock(current->mm);
vma = find_vma(current->mm, (unsigned long)ret);
if (vma)
vm_flags_set(vma, VM_USERMAP);
mmap_write_unlock(current->mm);
}
return ret;
}
void *vmalloc_user(unsigned long size)
{
return __vmalloc_user_flags(size, GFP_KERNEL | __GFP_ZERO);
}
EXPORT_SYMBOL(vmalloc_user);
struct page *vmalloc_to_page(const void *addr)
{
return virt_to_page(addr);
}
EXPORT_SYMBOL(vmalloc_to_page);
unsigned long vmalloc_to_pfn(const void *addr)
{
return page_to_pfn(virt_to_page(addr));
}
EXPORT_SYMBOL(vmalloc_to_pfn);
long vread_iter(struct iov_iter *iter, const char *addr, size_t count)
{
/* Don't allow overflow */
if ((unsigned long) addr + count < count)
count = -(unsigned long) addr;
return copy_to_iter(addr, count, iter);
}
/*
* vmalloc - allocate virtually contiguous memory
*
* @size: allocation size
*
* Allocate enough pages to cover @size from the page level
* allocator and map them into contiguous kernel virtual space.
*
* For tight control over page level allocator and protection flags
* use __vmalloc() instead.
*/
void *vmalloc(unsigned long size)
{
return __vmalloc(size, GFP_KERNEL);
}
EXPORT_SYMBOL(vmalloc);
void *vmalloc_huge(unsigned long size, gfp_t gfp_mask) __weak __alias(__vmalloc);
/*
* vzalloc - allocate virtually contiguous memory with zero fill
*
* @size: allocation size
*
* Allocate enough pages to cover @size from the page level
* allocator and map them into contiguous kernel virtual space.
* The memory allocated is set to zero.
*
* For tight control over page level allocator and protection flags
* use __vmalloc() instead.
*/
void *vzalloc(unsigned long size)
{
return __vmalloc(size, GFP_KERNEL | __GFP_ZERO);
}
EXPORT_SYMBOL(vzalloc);
/**
* vmalloc_node - allocate memory on a specific node
* @size: allocation size
* @node: numa node
*
* Allocate enough pages to cover @size from the page level
* allocator and map them into contiguous kernel virtual space.
*
* For tight control over page level allocator and protection flags
* use __vmalloc() instead.
*/
void *vmalloc_node(unsigned long size, int node)
{
return vmalloc(size);
}
EXPORT_SYMBOL(vmalloc_node);
/**
* vzalloc_node - allocate memory on a specific node with zero fill
* @size: allocation size
* @node: numa node
*
* Allocate enough pages to cover @size from the page level
* allocator and map them into contiguous kernel virtual space.
* The memory allocated is set to zero.
*
* For tight control over page level allocator and protection flags
* use __vmalloc() instead.
*/
void *vzalloc_node(unsigned long size, int node)
{
return vzalloc(size);
}
EXPORT_SYMBOL(vzalloc_node);
/**
* vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
* @size: allocation size
*
* Allocate enough 32bit PA addressable pages to cover @size from the
* page level allocator and map them into contiguous kernel virtual space.
*/
void *vmalloc_32(unsigned long size)
{
return __vmalloc(size, GFP_KERNEL);
}
EXPORT_SYMBOL(vmalloc_32);
/**
* vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
* @size: allocation size
*
* The resulting memory area is 32bit addressable and zeroed so it can be
* mapped to userspace without leaking data.
*
* VM_USERMAP is set on the corresponding VMA so that subsequent calls to
* remap_vmalloc_range() are permissible.
*/
void *vmalloc_32_user(unsigned long size)
{
/*
* We'll have to sort out the ZONE_DMA bits for 64-bit,
* but for now this can simply use vmalloc_user() directly.
*/
return vmalloc_user(size);
}
EXPORT_SYMBOL(vmalloc_32_user);
void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
{
BUG();
return NULL;
}
EXPORT_SYMBOL(vmap);
void vunmap(const void *addr)
{
BUG();
}
EXPORT_SYMBOL(vunmap);
void *vm_map_ram(struct page **pages, unsigned int count, int node)
{
BUG();
return NULL;
}
EXPORT_SYMBOL(vm_map_ram);
void vm_unmap_ram(const void *mem, unsigned int count)
{
BUG();
}
EXPORT_SYMBOL(vm_unmap_ram);
void vm_unmap_aliases(void)
{
}
EXPORT_SYMBOL_GPL(vm_unmap_aliases);
void free_vm_area(struct vm_struct *area)
{
BUG();
}
EXPORT_SYMBOL_GPL(free_vm_area);
int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
struct page *page)
{
return -EINVAL;
}
EXPORT_SYMBOL(vm_insert_page);
int vm_map_pages(struct vm_area_struct *vma, struct page **pages,
unsigned long num)
{
return -EINVAL;
}
EXPORT_SYMBOL(vm_map_pages);
int vm_map_pages_zero(struct vm_area_struct *vma, struct page **pages,
unsigned long num)
{
return -EINVAL;
}
EXPORT_SYMBOL(vm_map_pages_zero);
/*
* sys_brk() for the most part doesn't need the global kernel
* lock, except when an application is doing something nasty
* like trying to un-brk an area that has already been mapped
* to a regular file. in this case, the unmapping will need
* to invoke file system routines that need the global lock.
*/
SYSCALL_DEFINE1(brk, unsigned long, brk)
{
struct mm_struct *mm = current->mm;
if (brk < mm->start_brk || brk > mm->context.end_brk)
return mm->brk;
if (mm->brk == brk)
return mm->brk;
/*
* Always allow shrinking brk
*/
if (brk <= mm->brk) {
mm->brk = brk;
return brk;
}
/*
* Ok, looks good - let it rip.
*/
flush_icache_user_range(mm->brk, brk);
return mm->brk = brk;
}
/*
* initialise the percpu counter for VM and region record slabs
*/
void __init mmap_init(void)
{
int ret;
ret = percpu_counter_init(&vm_committed_as, 0, GFP_KERNEL);
VM_BUG_ON(ret);
vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC|SLAB_ACCOUNT);
}
/*
* validate the region tree
* - the caller must hold the region lock
*/
#ifdef CONFIG_DEBUG_NOMMU_REGIONS
static noinline void validate_nommu_regions(void)
{
struct vm_region *region, *last;
struct rb_node *p, *lastp;
lastp = rb_first(&nommu_region_tree);
if (!lastp)
return;
last = rb_entry(lastp, struct vm_region, vm_rb);
BUG_ON(last->vm_end <= last->vm_start);
BUG_ON(last->vm_top < last->vm_end);
while ((p = rb_next(lastp))) {
region = rb_entry(p, struct vm_region, vm_rb);
last = rb_entry(lastp, struct vm_region, vm_rb);
BUG_ON(region->vm_end <= region->vm_start);
BUG_ON(region->vm_top < region->vm_end);
BUG_ON(region->vm_start < last->vm_top);
lastp = p;
}
}
#else
static void validate_nommu_regions(void)
{
}
#endif
/*
* add a region into the global tree
*/
static void add_nommu_region(struct vm_region *region)
{
struct vm_region *pregion;
struct rb_node **p, *parent;
validate_nommu_regions();
parent = NULL;
p = &nommu_region_tree.rb_node;
while (*p) {
parent = *p;
pregion = rb_entry(parent, struct vm_region, vm_rb);
if (region->vm_start < pregion->vm_start)
p = &(*p)->rb_left;
else if (region->vm_start > pregion->vm_start)
p = &(*p)->rb_right;
else if (pregion == region)
return;
else
BUG();
}
rb_link_node(®ion->vm_rb, parent, p);
rb_insert_color(®ion->vm_rb, &nommu_region_tree);
validate_nommu_regions();
}
/*
* delete a region from the global tree
*/
static void delete_nommu_region(struct vm_region *region)
{
BUG_ON(!nommu_region_tree.rb_node);
validate_nommu_regions();
rb_erase(®ion->vm_rb, &nommu_region_tree);
validate_nommu_regions();
}
/*
* free a contiguous series of pages
*/
static void free_page_series(unsigned long from, unsigned long to)
{
for (; from < to; from += PAGE_SIZE) {
struct page *page = virt_to_page((void *)from);
atomic_long_dec(&mmap_pages_allocated);
put_page(page);
}
}
/*
* release a reference to a region
* - the caller must hold the region semaphore for writing, which this releases
* - the region may not have been added to the tree yet, in which case vm_top
* will equal vm_start
*/
static void __put_nommu_region(struct vm_region *region)
__releases(nommu_region_sem)
{
BUG_ON(!nommu_region_tree.rb_node);
if (--region->vm_usage == 0) {
if (region->vm_top > region->vm_start)
delete_nommu_region(region);
up_write(&nommu_region_sem);
if (region->vm_file)
fput(region->vm_file);
/* IO memory and memory shared directly out of the pagecache
* from ramfs/tmpfs mustn't be released here */
if (region->vm_flags & VM_MAPPED_COPY)
free_page_series(region->vm_start, region->vm_top);
kmem_cache_free(vm_region_jar, region);
} else {
up_write(&nommu_region_sem);
}
}
/*
* release a reference to a region
*/
static void put_nommu_region(struct vm_region *region)
{
down_write(&nommu_region_sem);
__put_nommu_region(region);
}
static void setup_vma_to_mm(struct vm_area_struct *vma, struct mm_struct *mm)
{
vma->vm_mm = mm;
/* add the VMA to the mapping */
if (vma->vm_file) {
struct address_space *mapping = vma->vm_file->f_mapping;
i_mmap_lock_write(mapping);
flush_dcache_mmap_lock(mapping);
vma_interval_tree_insert(vma, &mapping->i_mmap);
flush_dcache_mmap_unlock(mapping);
i_mmap_unlock_write(mapping);
}
}
static void cleanup_vma_from_mm(struct vm_area_struct *vma)
{
vma->vm_mm->map_count--;
/* remove the VMA from the mapping */
if (vma->vm_file) {
struct address_space *mapping;
mapping = vma->vm_file->f_mapping;
i_mmap_lock_write(mapping);
flush_dcache_mmap_lock(mapping);
vma_interval_tree_remove(vma, &mapping->i_mmap);
flush_dcache_mmap_unlock(mapping);
i_mmap_unlock_write(mapping);
}
}
/*
* delete a VMA from its owning mm_struct and address space
*/
static int delete_vma_from_mm(struct vm_area_struct *vma)
{
VMA_ITERATOR(vmi, vma->vm_mm, vma->vm_start);
vma_iter_config(&vmi, vma->vm_start, vma->vm_end);
if (vma_iter_prealloc(&vmi, vma)) {
pr_warn("Allocation of vma tree for process %d failed\n",
current->pid);
return -ENOMEM;
}
cleanup_vma_from_mm(vma);
/* remove from the MM's tree and list */
vma_iter_clear(&vmi);
return 0;
}
/*
* destroy a VMA record
*/
static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma)
{
if (vma->vm_ops && vma->vm_ops->close)
vma->vm_ops->close(vma);
if (vma->vm_file)
fput(vma->vm_file);
put_nommu_region(vma->vm_region);
vm_area_free(vma);
}
struct vm_area_struct *find_vma_intersection(struct mm_struct *mm,
unsigned long start_addr,
unsigned long end_addr)
{
unsigned long index = start_addr;
mmap_assert_locked(mm);
return mt_find(&mm->mm_mt, &index, end_addr - 1);
}
EXPORT_SYMBOL(find_vma_intersection);
/*
* look up the first VMA in which addr resides, NULL if none
* - should be called with mm->mmap_lock at least held readlocked
*/
struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
{
VMA_ITERATOR(vmi, mm, addr);
return vma_iter_load(&vmi);
}
EXPORT_SYMBOL(find_vma);
/*
* At least xtensa ends up having protection faults even with no
* MMU.. No stack expansion, at least.
*/
struct vm_area_struct *lock_mm_and_find_vma(struct mm_struct *mm,
unsigned long addr, struct pt_regs *regs)
{
struct vm_area_struct *vma;
mmap_read_lock(mm);
vma = vma_lookup(mm, addr);
if (!vma)
mmap_read_unlock(mm);
return vma;
}
/*
* expand a stack to a given address
* - not supported under NOMMU conditions
*/
int expand_stack_locked(struct vm_area_struct *vma, unsigned long addr)
{
return -ENOMEM;
}
struct vm_area_struct *expand_stack(struct mm_struct *mm, unsigned long addr)
{
mmap_read_unlock(mm);
return NULL;
}
/*
* look up the first VMA exactly that exactly matches addr
* - should be called with mm->mmap_lock at least held readlocked
*/
static struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
unsigned long addr,
unsigned long len)
{
struct vm_area_struct *vma;
unsigned long end = addr + len;
VMA_ITERATOR(vmi, mm, addr);
vma = vma_iter_load(&vmi);
if (!vma)
return NULL;
if (vma->vm_start != addr)
return NULL;
if (vma->vm_end != end)
return NULL;
return vma;
}
/*
* determine whether a mapping should be permitted and, if so, what sort of
* mapping we're capable of supporting
*/
static int validate_mmap_request(struct file *file,
unsigned long addr,
unsigned long len,
unsigned long prot,
unsigned long flags,
unsigned long pgoff,
unsigned long *_capabilities)
{
unsigned long capabilities, rlen;
int ret;
/* do the simple checks first */
if (flags & MAP_FIXED)
return -EINVAL;
if ((flags & MAP_TYPE) != MAP_PRIVATE &&
(flags & MAP_TYPE) != MAP_SHARED)
return -EINVAL;
if (!len)
return -EINVAL;
/* Careful about overflows.. */
rlen = PAGE_ALIGN(len);
if (!rlen || rlen > TASK_SIZE)
return -ENOMEM;
/* offset overflow? */
if ((pgoff + (rlen >> PAGE_SHIFT)) < pgoff)
return -EOVERFLOW;
if (file) {
/* files must support mmap */
if (!file->f_op->mmap)
return -ENODEV;
/* work out if what we've got could possibly be shared
* - we support chardevs that provide their own "memory"
* - we support files/blockdevs that are memory backed
*/
if (file->f_op->mmap_capabilities) {
capabilities = file->f_op->mmap_capabilities(file);
} else {
/* no explicit capabilities set, so assume some
* defaults */
switch (file_inode(file)->i_mode & S_IFMT) {
case S_IFREG:
case S_IFBLK:
capabilities = NOMMU_MAP_COPY;
break;
case S_IFCHR:
capabilities =
NOMMU_MAP_DIRECT |
NOMMU_MAP_READ |
NOMMU_MAP_WRITE;
break;
default:
return -EINVAL;
}
}
/* eliminate any capabilities that we can't support on this
* device */
if (!file->f_op->get_unmapped_area)
capabilities &= ~NOMMU_MAP_DIRECT;
if (!(file->f_mode & FMODE_CAN_READ))
capabilities &= ~NOMMU_MAP_COPY;
/* The file shall have been opened with read permission. */
if (!(file->f_mode & FMODE_READ))
return -EACCES;
if (flags & MAP_SHARED) {
/* do checks for writing, appending and locking */
if ((prot & PROT_WRITE) &&
!(file->f_mode & FMODE_WRITE))
return -EACCES;
if (IS_APPEND(file_inode(file)) &&
(file->f_mode & FMODE_WRITE))
return -EACCES;
if (!(capabilities & NOMMU_MAP_DIRECT))
return -ENODEV;
/* we mustn't privatise shared mappings */
capabilities &= ~NOMMU_MAP_COPY;
} else {
/* we're going to read the file into private memory we
* allocate */
if (!(capabilities & NOMMU_MAP_COPY))
return -ENODEV;
/* we don't permit a private writable mapping to be
* shared with the backing device */
if (prot & PROT_WRITE)
capabilities &= ~NOMMU_MAP_DIRECT;
}
if (capabilities & NOMMU_MAP_DIRECT) {
if (((prot & PROT_READ) && !(capabilities & NOMMU_MAP_READ)) ||
((prot & PROT_WRITE) && !(capabilities & NOMMU_MAP_WRITE)) ||
((prot & PROT_EXEC) && !(capabilities & NOMMU_MAP_EXEC))
) {
capabilities &= ~NOMMU_MAP_DIRECT;
if (flags & MAP_SHARED) {
pr_warn("MAP_SHARED not completely supported on !MMU\n");
return -EINVAL;
}
}
}
/* handle executable mappings and implied executable
* mappings */
if (path_noexec(&file->f_path)) {
if (prot & PROT_EXEC)
return -EPERM;
} else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
/* handle implication of PROT_EXEC by PROT_READ */
if (current->personality & READ_IMPLIES_EXEC) {
if (capabilities & NOMMU_MAP_EXEC)
prot |= PROT_EXEC;
}
} else if ((prot & PROT_READ) &&
(prot & PROT_EXEC) &&
!(capabilities & NOMMU_MAP_EXEC)
) {
/* backing file is not executable, try to copy */
capabilities &= ~NOMMU_MAP_DIRECT;
}
} else {
/* anonymous mappings are always memory backed and can be
* privately mapped
*/
capabilities = NOMMU_MAP_COPY;
/* handle PROT_EXEC implication by PROT_READ */
if ((prot & PROT_READ) &&
(current->personality & READ_IMPLIES_EXEC))
prot |= PROT_EXEC;
}
/* allow the security API to have its say */
ret = security_mmap_addr(addr);
if (ret < 0)
return ret;
/* looks okay */
*_capabilities = capabilities;
return 0;
}
/*
* we've determined that we can make the mapping, now translate what we
* now know into VMA flags
*/
static unsigned long determine_vm_flags(struct file *file,
unsigned long prot,
unsigned long flags,
unsigned long capabilities)
{
unsigned long vm_flags;
vm_flags = calc_vm_prot_bits(prot, 0) | calc_vm_flag_bits(flags);
if (!file) {
/*
* MAP_ANONYMOUS. MAP_SHARED is mapped to MAP_PRIVATE, because
* there is no fork().
*/
vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
} else if (flags & MAP_PRIVATE) {
/* MAP_PRIVATE file mapping */
if (capabilities & NOMMU_MAP_DIRECT)
vm_flags |= (capabilities & NOMMU_VMFLAGS);
else
vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
if (!(prot & PROT_WRITE) && !current->ptrace)
/*
* R/O private file mapping which cannot be used to
* modify memory, especially also not via active ptrace
* (e.g., set breakpoints) or later by upgrading
* permissions (no mprotect()). We can try overlaying
* the file mapping, which will work e.g., on chardevs,
* ramfs/tmpfs/shmfs and romfs/cramf.
*/
vm_flags |= VM_MAYOVERLAY;
} else {
/* MAP_SHARED file mapping: NOMMU_MAP_DIRECT is set. */
vm_flags |= VM_SHARED | VM_MAYSHARE |
(capabilities & NOMMU_VMFLAGS);
}
return vm_flags;
}
/*
* set up a shared mapping on a file (the driver or filesystem provides and
* pins the storage)
*/
static int do_mmap_shared_file(struct vm_area_struct *vma)
{
int ret;
ret = call_mmap(vma->vm_file, vma);
if (ret == 0) {
vma->vm_region->vm_top = vma->vm_region->vm_end;
return 0;
}
if (ret != -ENOSYS)
return ret;
/* getting -ENOSYS indicates that direct mmap isn't possible (as
* opposed to tried but failed) so we can only give a suitable error as
* it's not possible to make a private copy if MAP_SHARED was given */
return -ENODEV;
}
/*
* set up a private mapping or an anonymous shared mapping
*/
static int do_mmap_private(struct vm_area_struct *vma,
struct vm_region *region,
unsigned long len,
unsigned long capabilities)
{
unsigned long total, point;
void *base;
int ret, order;
/*
* Invoke the file's mapping function so that it can keep track of
* shared mappings on devices or memory. VM_MAYOVERLAY will be set if
* it may attempt to share, which will make is_nommu_shared_mapping()
* happy.
*/
if (capabilities & NOMMU_MAP_DIRECT) {
ret = call_mmap(vma->vm_file, vma);
/* shouldn't return success if we're not sharing */
if (WARN_ON_ONCE(!is_nommu_shared_mapping(vma->vm_flags)))
ret = -ENOSYS;
if (ret == 0) {
vma->vm_region->vm_top = vma->vm_region->vm_end;
return 0;
}
if (ret != -ENOSYS)
return ret;
/* getting an ENOSYS error indicates that direct mmap isn't
* possible (as opposed to tried but failed) so we'll try to
* make a private copy of the data and map that instead */
}
/* allocate some memory to hold the mapping
* - note that this may not return a page-aligned address if the object
* we're allocating is smaller than a page
*/
order = get_order(len);
total = 1 << order;
point = len >> PAGE_SHIFT;
/* we don't want to allocate a power-of-2 sized page set */
if (sysctl_nr_trim_pages && total - point >= sysctl_nr_trim_pages)
total = point;
base = alloc_pages_exact(total << PAGE_SHIFT, GFP_KERNEL);
if (!base)
goto enomem;
atomic_long_add(total, &mmap_pages_allocated);
vm_flags_set(vma, VM_MAPPED_COPY);
region->vm_flags = vma->vm_flags;
region->vm_start = (unsigned long) base;
region->vm_end = region->vm_start + len;
region->vm_top = region->vm_start + (total << PAGE_SHIFT);
vma->vm_start = region->vm_start;
vma->vm_end = region->vm_start + len;
if (vma->vm_file) {
/* read the contents of a file into the copy */
loff_t fpos;
fpos = vma->vm_pgoff;
fpos <<= PAGE_SHIFT;
ret = kernel_read(vma->vm_file, base, len, &fpos);
if (ret < 0)
goto error_free;
/* clear the last little bit */
if (ret < len)
memset(base + ret, 0, len - ret);
} else {
vma_set_anonymous(vma);
}
return 0;
error_free:
free_page_series(region->vm_start, region->vm_top);
region->vm_start = vma->vm_start = 0;
region->vm_end = vma->vm_end = 0;
region->vm_top = 0;
return ret;
enomem:
pr_err("Allocation of length %lu from process %d (%s) failed\n",
len, current->pid, current->comm);
show_mem();
return -ENOMEM;
}
/*
* handle mapping creation for uClinux
*/
unsigned long do_mmap(struct file *file,
unsigned long addr,
unsigned long len,
unsigned long prot,
unsigned long flags,
vm_flags_t vm_flags,
unsigned long pgoff,
unsigned long *populate,
struct list_head *uf)
{
struct vm_area_struct *vma;
struct vm_region *region;
struct rb_node *rb;
unsigned long capabilities, result;
int ret;
VMA_ITERATOR(vmi, current->mm, 0);
*populate = 0;
/* decide whether we should attempt the mapping, and if so what sort of
* mapping */
ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
&capabilities);
if (ret < 0)
return ret;
/* we ignore the address hint */
addr = 0;
len = PAGE_ALIGN(len);
/* we've determined that we can make the mapping, now translate what we
* now know into VMA flags */
vm_flags |= determine_vm_flags(file, prot, flags, capabilities);
/* we're going to need to record the mapping */
region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL);
if (!region)
goto error_getting_region;
vma = vm_area_alloc(current->mm);
if (!vma)
goto error_getting_vma;
region->vm_usage = 1;
region->vm_flags = vm_flags;
region->vm_pgoff = pgoff;
vm_flags_init(vma, vm_flags);
vma->vm_pgoff = pgoff;
if (file) {
region->vm_file = get_file(file);
vma->vm_file = get_file(file);
}
down_write(&nommu_region_sem);
/* if we want to share, we need to check for regions created by other
* mmap() calls that overlap with our proposed mapping
* - we can only share with a superset match on most regular files
* - shared mappings on character devices and memory backed files are
* permitted to overlap inexactly as far as we are concerned for in
* these cases, sharing is handled in the driver or filesystem rather
* than here
*/
if (is_nommu_shared_mapping(vm_flags)) {
struct vm_region *pregion;
unsigned long pglen, rpglen, pgend, rpgend, start;
pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
pgend = pgoff + pglen;
for (rb = rb_first(&nommu_region_tree); rb; rb = rb_next(rb)) {
pregion = rb_entry(rb, struct vm_region, vm_rb);
if (!is_nommu_shared_mapping(pregion->vm_flags))
continue;
/* search for overlapping mappings on the same file */
if (file_inode(pregion->vm_file) !=
file_inode(file))
continue;
if (pregion->vm_pgoff >= pgend)
continue;
rpglen = pregion->vm_end - pregion->vm_start;
rpglen = (rpglen + PAGE_SIZE - 1) >> PAGE_SHIFT;
rpgend = pregion->vm_pgoff + rpglen;
if (pgoff >= rpgend)
continue;
/* handle inexactly overlapping matches between
* mappings */
if ((pregion->vm_pgoff != pgoff || rpglen != pglen) &&
!(pgoff >= pregion->vm_pgoff && pgend <= rpgend)) {
/* new mapping is not a subset of the region */
if (!(capabilities & NOMMU_MAP_DIRECT))
goto sharing_violation;
continue;
}
/* we've found a region we can share */
pregion->vm_usage++;
vma->vm_region = pregion;
start = pregion->vm_start;
start += (pgoff - pregion->vm_pgoff) << PAGE_SHIFT;
vma->vm_start = start;
vma->vm_end = start + len;
if (pregion->vm_flags & VM_MAPPED_COPY)
vm_flags_set(vma, VM_MAPPED_COPY);
else {
ret = do_mmap_shared_file(vma);
if (ret < 0) {
vma->vm_region = NULL;
vma->vm_start = 0;
vma->vm_end = 0;
pregion->vm_usage--;
pregion = NULL;
goto error_just_free;
}
}
fput(region->vm_file);
kmem_cache_free(vm_region_jar, region);
region = pregion;
result = start;
goto share;
}
/* obtain the address at which to make a shared mapping
* - this is the hook for quasi-memory character devices to
* tell us the location of a shared mapping
*/
if (capabilities & NOMMU_MAP_DIRECT) {
addr = file->f_op->get_unmapped_area(file, addr, len,
pgoff, flags);
if (IS_ERR_VALUE(addr)) {
ret = addr;
if (ret != -ENOSYS)
goto error_just_free;
/* the driver refused to tell us where to site
* the mapping so we'll have to attempt to copy
* it */
ret = -ENODEV;
if (!(capabilities & NOMMU_MAP_COPY))
goto error_just_free;
capabilities &= ~NOMMU_MAP_DIRECT;
} else {
vma->vm_start = region->vm_start = addr;
vma->vm_end = region->vm_end = addr + len;
}
}
}
vma->vm_region = region;
/* set up the mapping
* - the region is filled in if NOMMU_MAP_DIRECT is still set
*/
if (file && vma->vm_flags & VM_SHARED)
ret = do_mmap_shared_file(vma);
else
ret = do_mmap_private(vma, region, len, capabilities);
if (ret < 0)
goto error_just_free;
add_nommu_region(region);
/* clear anonymous mappings that don't ask for uninitialized data */
if (!vma->vm_file &&
(!IS_ENABLED(CONFIG_MMAP_ALLOW_UNINITIALIZED) ||
!(flags & MAP_UNINITIALIZED)))
memset((void *)region->vm_start, 0,
region->vm_end - region->vm_start);
/* okay... we have a mapping; now we have to register it */
result = vma->vm_start;
current->mm->total_vm += len >> PAGE_SHIFT;
share:
BUG_ON(!vma->vm_region);
vma_iter_config(&vmi, vma->vm_start, vma->vm_end);
if (vma_iter_prealloc(&vmi, vma))
goto error_just_free;
setup_vma_to_mm(vma, current->mm);
current->mm->map_count++;
/* add the VMA to the tree */
vma_iter_store(&vmi, vma);
/* we flush the region from the icache only when the first executable
* mapping of it is made */
if (vma->vm_flags & VM_EXEC && !region->vm_icache_flushed) {
flush_icache_user_range(region->vm_start, region->vm_end);
region->vm_icache_flushed = true;
}
up_write(&nommu_region_sem);
return result;
error_just_free:
up_write(&nommu_region_sem);
error:
vma_iter_free(&vmi);
if (region->vm_file)
fput(region->vm_file);
kmem_cache_free(vm_region_jar, region);
if (vma->vm_file)
fput(vma->vm_file);
vm_area_free(vma);
return ret;
sharing_violation:
up_write(&nommu_region_sem);
pr_warn("Attempt to share mismatched mappings\n");
ret = -EINVAL;
goto error;
error_getting_vma:
kmem_cache_free(vm_region_jar, region);
pr_warn("Allocation of vma for %lu byte allocation from process %d failed\n",
len, current->pid);
show_mem();
return -ENOMEM;
error_getting_region:
pr_warn("Allocation of vm region for %lu byte allocation from process %d failed\n",
len, current->pid);
show_mem();
return -ENOMEM;
}
unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
unsigned long prot, unsigned long flags,
unsigned long fd, unsigned long pgoff)
{
struct file *file = NULL;
unsigned long retval = -EBADF;
audit_mmap_fd(fd, flags);
if (!(flags & MAP_ANONYMOUS)) {
file = fget(fd);
if (!file)
goto out;
}
retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
if (file)
fput(file);
out:
return retval;
}
SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
unsigned long, prot, unsigned long, flags,
unsigned long, fd, unsigned long, pgoff)
{
return ksys_mmap_pgoff(addr, len, prot, flags, fd, pgoff);
}
#ifdef __ARCH_WANT_SYS_OLD_MMAP
struct mmap_arg_struct {
unsigned long addr;
unsigned long len;
unsigned long prot;
unsigned long flags;
unsigned long fd;
unsigned long offset;
};
SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
{
struct mmap_arg_struct a;
if (copy_from_user(&a, arg, sizeof(a)))
return -EFAULT;
if (offset_in_page(a.offset))
return -EINVAL;
return ksys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
a.offset >> PAGE_SHIFT);
}
#endif /* __ARCH_WANT_SYS_OLD_MMAP */
/*
* split a vma into two pieces at address 'addr', a new vma is allocated either
* for the first part or the tail.
*/
int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
unsigned long addr, int new_below)
{
struct vm_area_struct *new;
struct vm_region *region;
unsigned long npages;
struct mm_struct *mm;
/* we're only permitted to split anonymous regions (these should have
* only a single usage on the region) */
if (vma->vm_file)
return -ENOMEM;
mm = vma->vm_mm;
if (mm->map_count >= sysctl_max_map_count)
return -ENOMEM;
region = kmem_cache_alloc(vm_region_jar, GFP_KERNEL);
if (!region)
return -ENOMEM;
new = vm_area_dup(vma);
if (!new)
goto err_vma_dup;
/* most fields are the same, copy all, and then fixup */
*region = *vma->vm_region;
new->vm_region = region;
npages = (addr - vma->vm_start) >> PAGE_SHIFT;
if (new_below) {
region->vm_top = region->vm_end = new->vm_end = addr;
} else {
region->vm_start = new->vm_start = addr;
region->vm_pgoff = new->vm_pgoff += npages;
}
vma_iter_config(vmi, new->vm_start, new->vm_end);
if (vma_iter_prealloc(vmi, vma)) {
pr_warn("Allocation of vma tree for process %d failed\n",
current->pid);
goto err_vmi_preallocate;
}
if (new->vm_ops && new->vm_ops->open)
new->vm_ops->open(new);
down_write(&nommu_region_sem);
delete_nommu_region(vma->vm_region);
if (new_below) {
vma->vm_region->vm_start = vma->vm_start = addr;
vma->vm_region->vm_pgoff = vma->vm_pgoff += npages;
} else {
vma->vm_region->vm_end = vma->vm_end = addr;
vma->vm_region->vm_top = addr;
}
add_nommu_region(vma->vm_region);
add_nommu_region(new->vm_region);
up_write(&nommu_region_sem);
setup_vma_to_mm(vma, mm);
setup_vma_to_mm(new, mm);
vma_iter_store(vmi, new);
mm->map_count++;
return 0;
err_vmi_preallocate:
vm_area_free(new);
err_vma_dup:
kmem_cache_free(vm_region_jar, region);
return -ENOMEM;
}
/*
* shrink a VMA by removing the specified chunk from either the beginning or
* the end
*/
static int vmi_shrink_vma(struct vma_iterator *vmi,
struct vm_area_struct *vma,
unsigned long from, unsigned long to)
{
struct vm_region *region;
/* adjust the VMA's pointers, which may reposition it in the MM's tree
* and list */
if (from > vma->vm_start) {
if (vma_iter_clear_gfp(vmi, from, vma->vm_end, GFP_KERNEL))
return -ENOMEM;
vma->vm_end = from;
} else {
if (vma_iter_clear_gfp(vmi, vma->vm_start, to, GFP_KERNEL))
return -ENOMEM;
vma->vm_start = to;
}
/* cut the backing region down to size */
region = vma->vm_region;
BUG_ON(region->vm_usage != 1);
down_write(&nommu_region_sem);
delete_nommu_region(region);
if (from > region->vm_start) {
to = region->vm_top;
region->vm_top = region->vm_end = from;
} else {
region->vm_start = to;
}
add_nommu_region(region);
up_write(&nommu_region_sem);
free_page_series(from, to);
return 0;
}
/*
* release a mapping
* - under NOMMU conditions the chunk to be unmapped must be backed by a single
* VMA, though it need not cover the whole VMA
*/
int do_munmap(struct mm_struct *mm, unsigned long start, size_t len, struct list_head *uf)
{
VMA_ITERATOR(vmi, mm, start);
struct vm_area_struct *vma;
unsigned long end;
int ret = 0;
len = PAGE_ALIGN(len);
if (len == 0)
return -EINVAL;
end = start + len;
/* find the first potentially overlapping VMA */
vma = vma_find(&vmi, end);
if (!vma) {
static int limit;
if (limit < 5) {
pr_warn("munmap of memory not mmapped by process %d (%s): 0x%lx-0x%lx\n",
current->pid, current->comm,
start, start + len - 1);
limit++;
}
return -EINVAL;
}
/* we're allowed to split an anonymous VMA but not a file-backed one */
if (vma->vm_file) {
do {
if (start > vma->vm_start)
return -EINVAL;
if (end == vma->vm_end)
goto erase_whole_vma;
vma = vma_find(&vmi, end);
} while (vma);
return -EINVAL;
} else {
/* the chunk must be a subset of the VMA found */
if (start == vma->vm_start && end == vma->vm_end)
goto erase_whole_vma;
if (start < vma->vm_start || end > vma->vm_end)
return -EINVAL;
if (offset_in_page(start))
return -EINVAL;
if (end != vma->vm_end && offset_in_page(end))
return -EINVAL;
if (start != vma->vm_start && end != vma->vm_end) {
ret = split_vma(&vmi, vma, start, 1);
if (ret < 0)
return ret;
}
return vmi_shrink_vma(&vmi, vma, start, end);
}
erase_whole_vma:
if (delete_vma_from_mm(vma))
ret = -ENOMEM;
else
delete_vma(mm, vma);
return ret;
}
int vm_munmap(unsigned long addr, size_t len)
{
struct mm_struct *mm = current->mm;
int ret;
mmap_write_lock(mm);
ret = do_munmap(mm, addr, len, NULL);
mmap_write_unlock(mm);
return ret;
}
EXPORT_SYMBOL(vm_munmap);
SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
{
return vm_munmap(addr, len);
}
/*
* release all the mappings made in a process's VM space
*/
void exit_mmap(struct mm_struct *mm)
{
VMA_ITERATOR(vmi, mm, 0);
struct vm_area_struct *vma;
if (!mm)
return;
mm->total_vm = 0;
/*
* Lock the mm to avoid assert complaining even though this is the only
* user of the mm
*/
mmap_write_lock(mm);
for_each_vma(vmi, vma) {
cleanup_vma_from_mm(vma);
delete_vma(mm, vma);
cond_resched();
}
__mt_destroy(&mm->mm_mt);
mmap_write_unlock(mm);
}
int vm_brk(unsigned long addr, unsigned long len)
{
return -ENOMEM;
}
/*
* expand (or shrink) an existing mapping, potentially moving it at the same
* time (controlled by the MREMAP_MAYMOVE flag and available VM space)
*
* under NOMMU conditions, we only permit changing a mapping's size, and only
* as long as it stays within the region allocated by do_mmap_private() and the
* block is not shareable
*
* MREMAP_FIXED is not supported under NOMMU conditions
*/
static unsigned long do_mremap(unsigned long addr,
unsigned long old_len, unsigned long new_len,
unsigned long flags, unsigned long new_addr)
{
struct vm_area_struct *vma;
/* insanity checks first */
old_len = PAGE_ALIGN(old_len);
new_len = PAGE_ALIGN(new_len);
if (old_len == 0 || new_len == 0)
return (unsigned long) -EINVAL;
if (offset_in_page(addr))
return -EINVAL;
if (flags & MREMAP_FIXED && new_addr != addr)
return (unsigned long) -EINVAL;
vma = find_vma_exact(current->mm, addr, old_len);
if (!vma)
return (unsigned long) -EINVAL;
if (vma->vm_end != vma->vm_start + old_len)
return (unsigned long) -EFAULT;
if (is_nommu_shared_mapping(vma->vm_flags))
return (unsigned long) -EPERM;
if (new_len > vma->vm_region->vm_end - vma->vm_region->vm_start)
return (unsigned long) -ENOMEM;
/* all checks complete - do it */
vma->vm_end = vma->vm_start + new_len;
return vma->vm_start;
}
SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
unsigned long, new_len, unsigned long, flags,
unsigned long, new_addr)
{
unsigned long ret;
mmap_write_lock(current->mm);
ret = do_mremap(addr, old_len, new_len, flags, new_addr);
mmap_write_unlock(current->mm);
return ret;
}
struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
unsigned int foll_flags)
{
return NULL;
}
int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
unsigned long pfn, unsigned long size, pgprot_t prot)
{
if (addr != (pfn << PAGE_SHIFT))
return -EINVAL;
vm_flags_set(vma, VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP);
return 0;
}
EXPORT_SYMBOL(remap_pfn_range);
int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len)
{
unsigned long pfn = start >> PAGE_SHIFT;
unsigned long vm_len = vma->vm_end - vma->vm_start;
pfn += vma->vm_pgoff;
return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot);
}
EXPORT_SYMBOL(vm_iomap_memory);
int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
unsigned long pgoff)
{
unsigned int size = vma->vm_end - vma->vm_start;
if (!(vma->vm_flags & VM_USERMAP))
return -EINVAL;
vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT));
vma->vm_end = vma->vm_start + size;
return 0;
}
EXPORT_SYMBOL(remap_vmalloc_range);
vm_fault_t filemap_fault(struct vm_fault *vmf)
{
BUG();
return 0;
}
EXPORT_SYMBOL(filemap_fault);
vm_fault_t filemap_map_pages(struct vm_fault *vmf,
pgoff_t start_pgoff, pgoff_t end_pgoff)
{
BUG();
return 0;
}
EXPORT_SYMBOL(filemap_map_pages);
int __access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf,
int len, unsigned int gup_flags)
{
struct vm_area_struct *vma;
int write = gup_flags & FOLL_WRITE;
if (mmap_read_lock_killable(mm))
return 0;
/* the access must start within one of the target process's mappings */
vma = find_vma(mm, addr);
if (vma) {
/* don't overrun this mapping */
if (addr + len >= vma->vm_end)
len = vma->vm_end - addr;
/* only read or write mappings where it is permitted */
if (write && vma->vm_flags & VM_MAYWRITE)
copy_to_user_page(vma, NULL, addr,
(void *) addr, buf, len);
else if (!write && vma->vm_flags & VM_MAYREAD)
copy_from_user_page(vma, NULL, addr,
buf, (void *) addr, len);
else
len = 0;
} else {
len = 0;
}
mmap_read_unlock(mm);
return len;
}
/**
* access_remote_vm - access another process' address space
* @mm: the mm_struct of the target address space
* @addr: start address to access
* @buf: source or destination buffer
* @len: number of bytes to transfer
* @gup_flags: flags modifying lookup behaviour
*
* The caller must hold a reference on @mm.
*/
int access_remote_vm(struct mm_struct *mm, unsigned long addr,
void *buf, int len, unsigned int gup_flags)
{
return __access_remote_vm(mm, addr, buf, len, gup_flags);
}
/*
* Access another process' address space.
* - source/target buffer must be kernel space
*/
int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len,
unsigned int gup_flags)
{
struct mm_struct *mm;
if (addr + len < addr)
return 0;
mm = get_task_mm(tsk);
if (!mm)
return 0;
len = __access_remote_vm(mm, addr, buf, len, gup_flags);
mmput(mm);
return len;
}
EXPORT_SYMBOL_GPL(access_process_vm);
/**
* nommu_shrink_inode_mappings - Shrink the shared mappings on an inode
* @inode: The inode to check
* @size: The current filesize of the inode
* @newsize: The proposed filesize of the inode
*
* Check the shared mappings on an inode on behalf of a shrinking truncate to
* make sure that any outstanding VMAs aren't broken and then shrink the
* vm_regions that extend beyond so that do_mmap() doesn't
* automatically grant mappings that are too large.
*/
int nommu_shrink_inode_mappings(struct inode *inode, size_t size,
size_t newsize)
{
struct vm_area_struct *vma;
struct vm_region *region;
pgoff_t low, high;
size_t r_size, r_top;
low = newsize >> PAGE_SHIFT;
high = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
down_write(&nommu_region_sem);
i_mmap_lock_read(inode->i_mapping);
/* search for VMAs that fall within the dead zone */
vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap, low, high) {
/* found one - only interested if it's shared out of the page
* cache */
if (vma->vm_flags & VM_SHARED) {
i_mmap_unlock_read(inode->i_mapping);
up_write(&nommu_region_sem);
return -ETXTBSY; /* not quite true, but near enough */
}
}
/* reduce any regions that overlap the dead zone - if in existence,
* these will be pointed to by VMAs that don't overlap the dead zone
*
* we don't check for any regions that start beyond the EOF as there
* shouldn't be any
*/
vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap, 0, ULONG_MAX) {
if (!(vma->vm_flags & VM_SHARED))
continue;
region = vma->vm_region;
r_size = region->vm_top - region->vm_start;
r_top = (region->vm_pgoff << PAGE_SHIFT) + r_size;
if (r_top > newsize) {
region->vm_top -= r_top - newsize;
if (region->vm_end > region->vm_top)
region->vm_end = region->vm_top;
}
}
i_mmap_unlock_read(inode->i_mapping);
up_write(&nommu_region_sem);
return 0;
}
/*
* Initialise sysctl_user_reserve_kbytes.
*
* This is intended to prevent a user from starting a single memory hogging
* process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER
* mode.
*
* The default value is min(3% of free memory, 128MB)
* 128MB is enough to recover with sshd/login, bash, and top/kill.
*/
static int __meminit init_user_reserve(void)
{
unsigned long free_kbytes;
free_kbytes = K(global_zone_page_state(NR_FREE_PAGES));
sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17);
return 0;
}
subsys_initcall(init_user_reserve);
/*
* Initialise sysctl_admin_reserve_kbytes.
*
* The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin
* to log in and kill a memory hogging process.
*
* Systems with more than 256MB will reserve 8MB, enough to recover
* with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will
* only reserve 3% of free pages by default.
*/
static int __meminit init_admin_reserve(void)
{
unsigned long free_kbytes;
free_kbytes = K(global_zone_page_state(NR_FREE_PAGES));
sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13);
return 0;
}
subsys_initcall(init_admin_reserve);
| linux-master | mm/nommu.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/fault-inject.h>
#include <linux/mm.h>
static struct {
struct fault_attr attr;
bool ignore_gfp_highmem;
bool ignore_gfp_reclaim;
u32 min_order;
} fail_page_alloc = {
.attr = FAULT_ATTR_INITIALIZER,
.ignore_gfp_reclaim = true,
.ignore_gfp_highmem = true,
.min_order = 1,
};
static int __init setup_fail_page_alloc(char *str)
{
return setup_fault_attr(&fail_page_alloc.attr, str);
}
__setup("fail_page_alloc=", setup_fail_page_alloc);
bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
{
int flags = 0;
if (order < fail_page_alloc.min_order)
return false;
if (gfp_mask & __GFP_NOFAIL)
return false;
if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
return false;
if (fail_page_alloc.ignore_gfp_reclaim &&
(gfp_mask & __GFP_DIRECT_RECLAIM))
return false;
/* See comment in __should_failslab() */
if (gfp_mask & __GFP_NOWARN)
flags |= FAULT_NOWARN;
return should_fail_ex(&fail_page_alloc.attr, 1 << order, flags);
}
#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
static int __init fail_page_alloc_debugfs(void)
{
umode_t mode = S_IFREG | 0600;
struct dentry *dir;
dir = fault_create_debugfs_attr("fail_page_alloc", NULL,
&fail_page_alloc.attr);
debugfs_create_bool("ignore-gfp-wait", mode, dir,
&fail_page_alloc.ignore_gfp_reclaim);
debugfs_create_bool("ignore-gfp-highmem", mode, dir,
&fail_page_alloc.ignore_gfp_highmem);
debugfs_create_u32("min-order", mode, dir, &fail_page_alloc.min_order);
return 0;
}
late_initcall(fail_page_alloc_debugfs);
#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
| linux-master | mm/fail_page_alloc.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/mm/memory_hotplug.c
*
* Copyright (C)
*/
#include <linux/stddef.h>
#include <linux/mm.h>
#include <linux/sched/signal.h>
#include <linux/swap.h>
#include <linux/interrupt.h>
#include <linux/pagemap.h>
#include <linux/compiler.h>
#include <linux/export.h>
#include <linux/writeback.h>
#include <linux/slab.h>
#include <linux/sysctl.h>
#include <linux/cpu.h>
#include <linux/memory.h>
#include <linux/memremap.h>
#include <linux/memory_hotplug.h>
#include <linux/vmalloc.h>
#include <linux/ioport.h>
#include <linux/delay.h>
#include <linux/migrate.h>
#include <linux/page-isolation.h>
#include <linux/pfn.h>
#include <linux/suspend.h>
#include <linux/mm_inline.h>
#include <linux/firmware-map.h>
#include <linux/stop_machine.h>
#include <linux/hugetlb.h>
#include <linux/memblock.h>
#include <linux/compaction.h>
#include <linux/rmap.h>
#include <linux/module.h>
#include <asm/tlbflush.h>
#include "internal.h"
#include "shuffle.h"
enum {
MEMMAP_ON_MEMORY_DISABLE = 0,
MEMMAP_ON_MEMORY_ENABLE,
MEMMAP_ON_MEMORY_FORCE,
};
static int memmap_mode __read_mostly = MEMMAP_ON_MEMORY_DISABLE;
static inline unsigned long memory_block_memmap_size(void)
{
return PHYS_PFN(memory_block_size_bytes()) * sizeof(struct page);
}
static inline unsigned long memory_block_memmap_on_memory_pages(void)
{
unsigned long nr_pages = PFN_UP(memory_block_memmap_size());
/*
* In "forced" memmap_on_memory mode, we add extra pages to align the
* vmemmap size to cover full pageblocks. That way, we can add memory
* even if the vmemmap size is not properly aligned, however, we might waste
* memory.
*/
if (memmap_mode == MEMMAP_ON_MEMORY_FORCE)
return pageblock_align(nr_pages);
return nr_pages;
}
#ifdef CONFIG_MHP_MEMMAP_ON_MEMORY
/*
* memory_hotplug.memmap_on_memory parameter
*/
static int set_memmap_mode(const char *val, const struct kernel_param *kp)
{
int ret, mode;
bool enabled;
if (sysfs_streq(val, "force") || sysfs_streq(val, "FORCE")) {
mode = MEMMAP_ON_MEMORY_FORCE;
} else {
ret = kstrtobool(val, &enabled);
if (ret < 0)
return ret;
if (enabled)
mode = MEMMAP_ON_MEMORY_ENABLE;
else
mode = MEMMAP_ON_MEMORY_DISABLE;
}
*((int *)kp->arg) = mode;
if (mode == MEMMAP_ON_MEMORY_FORCE) {
unsigned long memmap_pages = memory_block_memmap_on_memory_pages();
pr_info_once("Memory hotplug will waste %ld pages in each memory block\n",
memmap_pages - PFN_UP(memory_block_memmap_size()));
}
return 0;
}
static int get_memmap_mode(char *buffer, const struct kernel_param *kp)
{
if (*((int *)kp->arg) == MEMMAP_ON_MEMORY_FORCE)
return sprintf(buffer, "force\n");
return param_get_bool(buffer, kp);
}
static const struct kernel_param_ops memmap_mode_ops = {
.set = set_memmap_mode,
.get = get_memmap_mode,
};
module_param_cb(memmap_on_memory, &memmap_mode_ops, &memmap_mode, 0444);
MODULE_PARM_DESC(memmap_on_memory, "Enable memmap on memory for memory hotplug\n"
"With value \"force\" it could result in memory wastage due "
"to memmap size limitations (Y/N/force)");
static inline bool mhp_memmap_on_memory(void)
{
return memmap_mode != MEMMAP_ON_MEMORY_DISABLE;
}
#else
static inline bool mhp_memmap_on_memory(void)
{
return false;
}
#endif
enum {
ONLINE_POLICY_CONTIG_ZONES = 0,
ONLINE_POLICY_AUTO_MOVABLE,
};
static const char * const online_policy_to_str[] = {
[ONLINE_POLICY_CONTIG_ZONES] = "contig-zones",
[ONLINE_POLICY_AUTO_MOVABLE] = "auto-movable",
};
static int set_online_policy(const char *val, const struct kernel_param *kp)
{
int ret = sysfs_match_string(online_policy_to_str, val);
if (ret < 0)
return ret;
*((int *)kp->arg) = ret;
return 0;
}
static int get_online_policy(char *buffer, const struct kernel_param *kp)
{
return sprintf(buffer, "%s\n", online_policy_to_str[*((int *)kp->arg)]);
}
/*
* memory_hotplug.online_policy: configure online behavior when onlining without
* specifying a zone (MMOP_ONLINE)
*
* "contig-zones": keep zone contiguous
* "auto-movable": online memory to ZONE_MOVABLE if the configuration
* (auto_movable_ratio, auto_movable_numa_aware) allows for it
*/
static int online_policy __read_mostly = ONLINE_POLICY_CONTIG_ZONES;
static const struct kernel_param_ops online_policy_ops = {
.set = set_online_policy,
.get = get_online_policy,
};
module_param_cb(online_policy, &online_policy_ops, &online_policy, 0644);
MODULE_PARM_DESC(online_policy,
"Set the online policy (\"contig-zones\", \"auto-movable\") "
"Default: \"contig-zones\"");
/*
* memory_hotplug.auto_movable_ratio: specify maximum MOVABLE:KERNEL ratio
*
* The ratio represent an upper limit and the kernel might decide to not
* online some memory to ZONE_MOVABLE -- e.g., because hotplugged KERNEL memory
* doesn't allow for more MOVABLE memory.
*/
static unsigned int auto_movable_ratio __read_mostly = 301;
module_param(auto_movable_ratio, uint, 0644);
MODULE_PARM_DESC(auto_movable_ratio,
"Set the maximum ratio of MOVABLE:KERNEL memory in the system "
"in percent for \"auto-movable\" online policy. Default: 301");
/*
* memory_hotplug.auto_movable_numa_aware: consider numa node stats
*/
#ifdef CONFIG_NUMA
static bool auto_movable_numa_aware __read_mostly = true;
module_param(auto_movable_numa_aware, bool, 0644);
MODULE_PARM_DESC(auto_movable_numa_aware,
"Consider numa node stats in addition to global stats in "
"\"auto-movable\" online policy. Default: true");
#endif /* CONFIG_NUMA */
/*
* online_page_callback contains pointer to current page onlining function.
* Initially it is generic_online_page(). If it is required it could be
* changed by calling set_online_page_callback() for callback registration
* and restore_online_page_callback() for generic callback restore.
*/
static online_page_callback_t online_page_callback = generic_online_page;
static DEFINE_MUTEX(online_page_callback_lock);
DEFINE_STATIC_PERCPU_RWSEM(mem_hotplug_lock);
void get_online_mems(void)
{
percpu_down_read(&mem_hotplug_lock);
}
void put_online_mems(void)
{
percpu_up_read(&mem_hotplug_lock);
}
bool movable_node_enabled = false;
#ifndef CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE
int mhp_default_online_type = MMOP_OFFLINE;
#else
int mhp_default_online_type = MMOP_ONLINE;
#endif
static int __init setup_memhp_default_state(char *str)
{
const int online_type = mhp_online_type_from_str(str);
if (online_type >= 0)
mhp_default_online_type = online_type;
return 1;
}
__setup("memhp_default_state=", setup_memhp_default_state);
void mem_hotplug_begin(void)
{
cpus_read_lock();
percpu_down_write(&mem_hotplug_lock);
}
void mem_hotplug_done(void)
{
percpu_up_write(&mem_hotplug_lock);
cpus_read_unlock();
}
u64 max_mem_size = U64_MAX;
/* add this memory to iomem resource */
static struct resource *register_memory_resource(u64 start, u64 size,
const char *resource_name)
{
struct resource *res;
unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
if (strcmp(resource_name, "System RAM"))
flags |= IORESOURCE_SYSRAM_DRIVER_MANAGED;
if (!mhp_range_allowed(start, size, true))
return ERR_PTR(-E2BIG);
/*
* Make sure value parsed from 'mem=' only restricts memory adding
* while booting, so that memory hotplug won't be impacted. Please
* refer to document of 'mem=' in kernel-parameters.txt for more
* details.
*/
if (start + size > max_mem_size && system_state < SYSTEM_RUNNING)
return ERR_PTR(-E2BIG);
/*
* Request ownership of the new memory range. This might be
* a child of an existing resource that was present but
* not marked as busy.
*/
res = __request_region(&iomem_resource, start, size,
resource_name, flags);
if (!res) {
pr_debug("Unable to reserve System RAM region: %016llx->%016llx\n",
start, start + size);
return ERR_PTR(-EEXIST);
}
return res;
}
static void release_memory_resource(struct resource *res)
{
if (!res)
return;
release_resource(res);
kfree(res);
}
static int check_pfn_span(unsigned long pfn, unsigned long nr_pages)
{
/*
* Disallow all operations smaller than a sub-section and only
* allow operations smaller than a section for
* SPARSEMEM_VMEMMAP. Note that check_hotplug_memory_range()
* enforces a larger memory_block_size_bytes() granularity for
* memory that will be marked online, so this check should only
* fire for direct arch_{add,remove}_memory() users outside of
* add_memory_resource().
*/
unsigned long min_align;
if (IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP))
min_align = PAGES_PER_SUBSECTION;
else
min_align = PAGES_PER_SECTION;
if (!IS_ALIGNED(pfn | nr_pages, min_align))
return -EINVAL;
return 0;
}
/*
* Return page for the valid pfn only if the page is online. All pfn
* walkers which rely on the fully initialized page->flags and others
* should use this rather than pfn_valid && pfn_to_page
*/
struct page *pfn_to_online_page(unsigned long pfn)
{
unsigned long nr = pfn_to_section_nr(pfn);
struct dev_pagemap *pgmap;
struct mem_section *ms;
if (nr >= NR_MEM_SECTIONS)
return NULL;
ms = __nr_to_section(nr);
if (!online_section(ms))
return NULL;
/*
* Save some code text when online_section() +
* pfn_section_valid() are sufficient.
*/
if (IS_ENABLED(CONFIG_HAVE_ARCH_PFN_VALID) && !pfn_valid(pfn))
return NULL;
if (!pfn_section_valid(ms, pfn))
return NULL;
if (!online_device_section(ms))
return pfn_to_page(pfn);
/*
* Slowpath: when ZONE_DEVICE collides with
* ZONE_{NORMAL,MOVABLE} within the same section some pfns in
* the section may be 'offline' but 'valid'. Only
* get_dev_pagemap() can determine sub-section online status.
*/
pgmap = get_dev_pagemap(pfn, NULL);
put_dev_pagemap(pgmap);
/* The presence of a pgmap indicates ZONE_DEVICE offline pfn */
if (pgmap)
return NULL;
return pfn_to_page(pfn);
}
EXPORT_SYMBOL_GPL(pfn_to_online_page);
int __ref __add_pages(int nid, unsigned long pfn, unsigned long nr_pages,
struct mhp_params *params)
{
const unsigned long end_pfn = pfn + nr_pages;
unsigned long cur_nr_pages;
int err;
struct vmem_altmap *altmap = params->altmap;
if (WARN_ON_ONCE(!pgprot_val(params->pgprot)))
return -EINVAL;
VM_BUG_ON(!mhp_range_allowed(PFN_PHYS(pfn), nr_pages * PAGE_SIZE, false));
if (altmap) {
/*
* Validate altmap is within bounds of the total request
*/
if (altmap->base_pfn != pfn
|| vmem_altmap_offset(altmap) > nr_pages) {
pr_warn_once("memory add fail, invalid altmap\n");
return -EINVAL;
}
altmap->alloc = 0;
}
if (check_pfn_span(pfn, nr_pages)) {
WARN(1, "Misaligned %s start: %#lx end: %#lx\n", __func__, pfn, pfn + nr_pages - 1);
return -EINVAL;
}
for (; pfn < end_pfn; pfn += cur_nr_pages) {
/* Select all remaining pages up to the next section boundary */
cur_nr_pages = min(end_pfn - pfn,
SECTION_ALIGN_UP(pfn + 1) - pfn);
err = sparse_add_section(nid, pfn, cur_nr_pages, altmap,
params->pgmap);
if (err)
break;
cond_resched();
}
vmemmap_populate_print_last();
return err;
}
/* find the smallest valid pfn in the range [start_pfn, end_pfn) */
static unsigned long find_smallest_section_pfn(int nid, struct zone *zone,
unsigned long start_pfn,
unsigned long end_pfn)
{
for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SUBSECTION) {
if (unlikely(!pfn_to_online_page(start_pfn)))
continue;
if (unlikely(pfn_to_nid(start_pfn) != nid))
continue;
if (zone != page_zone(pfn_to_page(start_pfn)))
continue;
return start_pfn;
}
return 0;
}
/* find the biggest valid pfn in the range [start_pfn, end_pfn). */
static unsigned long find_biggest_section_pfn(int nid, struct zone *zone,
unsigned long start_pfn,
unsigned long end_pfn)
{
unsigned long pfn;
/* pfn is the end pfn of a memory section. */
pfn = end_pfn - 1;
for (; pfn >= start_pfn; pfn -= PAGES_PER_SUBSECTION) {
if (unlikely(!pfn_to_online_page(pfn)))
continue;
if (unlikely(pfn_to_nid(pfn) != nid))
continue;
if (zone != page_zone(pfn_to_page(pfn)))
continue;
return pfn;
}
return 0;
}
static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,
unsigned long end_pfn)
{
unsigned long pfn;
int nid = zone_to_nid(zone);
if (zone->zone_start_pfn == start_pfn) {
/*
* If the section is smallest section in the zone, it need
* shrink zone->zone_start_pfn and zone->zone_spanned_pages.
* In this case, we find second smallest valid mem_section
* for shrinking zone.
*/
pfn = find_smallest_section_pfn(nid, zone, end_pfn,
zone_end_pfn(zone));
if (pfn) {
zone->spanned_pages = zone_end_pfn(zone) - pfn;
zone->zone_start_pfn = pfn;
} else {
zone->zone_start_pfn = 0;
zone->spanned_pages = 0;
}
} else if (zone_end_pfn(zone) == end_pfn) {
/*
* If the section is biggest section in the zone, it need
* shrink zone->spanned_pages.
* In this case, we find second biggest valid mem_section for
* shrinking zone.
*/
pfn = find_biggest_section_pfn(nid, zone, zone->zone_start_pfn,
start_pfn);
if (pfn)
zone->spanned_pages = pfn - zone->zone_start_pfn + 1;
else {
zone->zone_start_pfn = 0;
zone->spanned_pages = 0;
}
}
}
static void update_pgdat_span(struct pglist_data *pgdat)
{
unsigned long node_start_pfn = 0, node_end_pfn = 0;
struct zone *zone;
for (zone = pgdat->node_zones;
zone < pgdat->node_zones + MAX_NR_ZONES; zone++) {
unsigned long end_pfn = zone_end_pfn(zone);
/* No need to lock the zones, they can't change. */
if (!zone->spanned_pages)
continue;
if (!node_end_pfn) {
node_start_pfn = zone->zone_start_pfn;
node_end_pfn = end_pfn;
continue;
}
if (end_pfn > node_end_pfn)
node_end_pfn = end_pfn;
if (zone->zone_start_pfn < node_start_pfn)
node_start_pfn = zone->zone_start_pfn;
}
pgdat->node_start_pfn = node_start_pfn;
pgdat->node_spanned_pages = node_end_pfn - node_start_pfn;
}
void __ref remove_pfn_range_from_zone(struct zone *zone,
unsigned long start_pfn,
unsigned long nr_pages)
{
const unsigned long end_pfn = start_pfn + nr_pages;
struct pglist_data *pgdat = zone->zone_pgdat;
unsigned long pfn, cur_nr_pages;
/* Poison struct pages because they are now uninitialized again. */
for (pfn = start_pfn; pfn < end_pfn; pfn += cur_nr_pages) {
cond_resched();
/* Select all remaining pages up to the next section boundary */
cur_nr_pages =
min(end_pfn - pfn, SECTION_ALIGN_UP(pfn + 1) - pfn);
page_init_poison(pfn_to_page(pfn),
sizeof(struct page) * cur_nr_pages);
}
/*
* Zone shrinking code cannot properly deal with ZONE_DEVICE. So
* we will not try to shrink the zones - which is okay as
* set_zone_contiguous() cannot deal with ZONE_DEVICE either way.
*/
if (zone_is_zone_device(zone))
return;
clear_zone_contiguous(zone);
shrink_zone_span(zone, start_pfn, start_pfn + nr_pages);
update_pgdat_span(pgdat);
set_zone_contiguous(zone);
}
/**
* __remove_pages() - remove sections of pages
* @pfn: starting pageframe (must be aligned to start of a section)
* @nr_pages: number of pages to remove (must be multiple of section size)
* @altmap: alternative device page map or %NULL if default memmap is used
*
* Generic helper function to remove section mappings and sysfs entries
* for the section of the memory we are removing. Caller needs to make
* sure that pages are marked reserved and zones are adjust properly by
* calling offline_pages().
*/
void __remove_pages(unsigned long pfn, unsigned long nr_pages,
struct vmem_altmap *altmap)
{
const unsigned long end_pfn = pfn + nr_pages;
unsigned long cur_nr_pages;
if (check_pfn_span(pfn, nr_pages)) {
WARN(1, "Misaligned %s start: %#lx end: %#lx\n", __func__, pfn, pfn + nr_pages - 1);
return;
}
for (; pfn < end_pfn; pfn += cur_nr_pages) {
cond_resched();
/* Select all remaining pages up to the next section boundary */
cur_nr_pages = min(end_pfn - pfn,
SECTION_ALIGN_UP(pfn + 1) - pfn);
sparse_remove_section(pfn, cur_nr_pages, altmap);
}
}
int set_online_page_callback(online_page_callback_t callback)
{
int rc = -EINVAL;
get_online_mems();
mutex_lock(&online_page_callback_lock);
if (online_page_callback == generic_online_page) {
online_page_callback = callback;
rc = 0;
}
mutex_unlock(&online_page_callback_lock);
put_online_mems();
return rc;
}
EXPORT_SYMBOL_GPL(set_online_page_callback);
int restore_online_page_callback(online_page_callback_t callback)
{
int rc = -EINVAL;
get_online_mems();
mutex_lock(&online_page_callback_lock);
if (online_page_callback == callback) {
online_page_callback = generic_online_page;
rc = 0;
}
mutex_unlock(&online_page_callback_lock);
put_online_mems();
return rc;
}
EXPORT_SYMBOL_GPL(restore_online_page_callback);
void generic_online_page(struct page *page, unsigned int order)
{
/*
* Freeing the page with debug_pagealloc enabled will try to unmap it,
* so we should map it first. This is better than introducing a special
* case in page freeing fast path.
*/
debug_pagealloc_map_pages(page, 1 << order);
__free_pages_core(page, order);
totalram_pages_add(1UL << order);
}
EXPORT_SYMBOL_GPL(generic_online_page);
static void online_pages_range(unsigned long start_pfn, unsigned long nr_pages)
{
const unsigned long end_pfn = start_pfn + nr_pages;
unsigned long pfn;
/*
* Online the pages in MAX_ORDER aligned chunks. The callback might
* decide to not expose all pages to the buddy (e.g., expose them
* later). We account all pages as being online and belonging to this
* zone ("present").
* When using memmap_on_memory, the range might not be aligned to
* MAX_ORDER_NR_PAGES - 1, but pageblock aligned. __ffs() will detect
* this and the first chunk to online will be pageblock_nr_pages.
*/
for (pfn = start_pfn; pfn < end_pfn;) {
int order;
/*
* Free to online pages in the largest chunks alignment allows.
*
* __ffs() behaviour is undefined for 0. start == 0 is
* MAX_ORDER-aligned, Set order to MAX_ORDER for the case.
*/
if (pfn)
order = min_t(int, MAX_ORDER, __ffs(pfn));
else
order = MAX_ORDER;
(*online_page_callback)(pfn_to_page(pfn), order);
pfn += (1UL << order);
}
/* mark all involved sections as online */
online_mem_sections(start_pfn, end_pfn);
}
/* check which state of node_states will be changed when online memory */
static void node_states_check_changes_online(unsigned long nr_pages,
struct zone *zone, struct memory_notify *arg)
{
int nid = zone_to_nid(zone);
arg->status_change_nid = NUMA_NO_NODE;
arg->status_change_nid_normal = NUMA_NO_NODE;
if (!node_state(nid, N_MEMORY))
arg->status_change_nid = nid;
if (zone_idx(zone) <= ZONE_NORMAL && !node_state(nid, N_NORMAL_MEMORY))
arg->status_change_nid_normal = nid;
}
static void node_states_set_node(int node, struct memory_notify *arg)
{
if (arg->status_change_nid_normal >= 0)
node_set_state(node, N_NORMAL_MEMORY);
if (arg->status_change_nid >= 0)
node_set_state(node, N_MEMORY);
}
static void __meminit resize_zone_range(struct zone *zone, unsigned long start_pfn,
unsigned long nr_pages)
{
unsigned long old_end_pfn = zone_end_pfn(zone);
if (zone_is_empty(zone) || start_pfn < zone->zone_start_pfn)
zone->zone_start_pfn = start_pfn;
zone->spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - zone->zone_start_pfn;
}
static void __meminit resize_pgdat_range(struct pglist_data *pgdat, unsigned long start_pfn,
unsigned long nr_pages)
{
unsigned long old_end_pfn = pgdat_end_pfn(pgdat);
if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn)
pgdat->node_start_pfn = start_pfn;
pgdat->node_spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - pgdat->node_start_pfn;
}
#ifdef CONFIG_ZONE_DEVICE
static void section_taint_zone_device(unsigned long pfn)
{
struct mem_section *ms = __pfn_to_section(pfn);
ms->section_mem_map |= SECTION_TAINT_ZONE_DEVICE;
}
#else
static inline void section_taint_zone_device(unsigned long pfn)
{
}
#endif
/*
* Associate the pfn range with the given zone, initializing the memmaps
* and resizing the pgdat/zone data to span the added pages. After this
* call, all affected pages are PG_reserved.
*
* All aligned pageblocks are initialized to the specified migratetype
* (usually MIGRATE_MOVABLE). Besides setting the migratetype, no related
* zone stats (e.g., nr_isolate_pageblock) are touched.
*/
void __ref move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn,
unsigned long nr_pages,
struct vmem_altmap *altmap, int migratetype)
{
struct pglist_data *pgdat = zone->zone_pgdat;
int nid = pgdat->node_id;
clear_zone_contiguous(zone);
if (zone_is_empty(zone))
init_currently_empty_zone(zone, start_pfn, nr_pages);
resize_zone_range(zone, start_pfn, nr_pages);
resize_pgdat_range(pgdat, start_pfn, nr_pages);
/*
* Subsection population requires care in pfn_to_online_page().
* Set the taint to enable the slow path detection of
* ZONE_DEVICE pages in an otherwise ZONE_{NORMAL,MOVABLE}
* section.
*/
if (zone_is_zone_device(zone)) {
if (!IS_ALIGNED(start_pfn, PAGES_PER_SECTION))
section_taint_zone_device(start_pfn);
if (!IS_ALIGNED(start_pfn + nr_pages, PAGES_PER_SECTION))
section_taint_zone_device(start_pfn + nr_pages);
}
/*
* TODO now we have a visible range of pages which are not associated
* with their zone properly. Not nice but set_pfnblock_flags_mask
* expects the zone spans the pfn range. All the pages in the range
* are reserved so nobody should be touching them so we should be safe
*/
memmap_init_range(nr_pages, nid, zone_idx(zone), start_pfn, 0,
MEMINIT_HOTPLUG, altmap, migratetype);
set_zone_contiguous(zone);
}
struct auto_movable_stats {
unsigned long kernel_early_pages;
unsigned long movable_pages;
};
static void auto_movable_stats_account_zone(struct auto_movable_stats *stats,
struct zone *zone)
{
if (zone_idx(zone) == ZONE_MOVABLE) {
stats->movable_pages += zone->present_pages;
} else {
stats->kernel_early_pages += zone->present_early_pages;
#ifdef CONFIG_CMA
/*
* CMA pages (never on hotplugged memory) behave like
* ZONE_MOVABLE.
*/
stats->movable_pages += zone->cma_pages;
stats->kernel_early_pages -= zone->cma_pages;
#endif /* CONFIG_CMA */
}
}
struct auto_movable_group_stats {
unsigned long movable_pages;
unsigned long req_kernel_early_pages;
};
static int auto_movable_stats_account_group(struct memory_group *group,
void *arg)
{
const int ratio = READ_ONCE(auto_movable_ratio);
struct auto_movable_group_stats *stats = arg;
long pages;
/*
* We don't support modifying the config while the auto-movable online
* policy is already enabled. Just avoid the division by zero below.
*/
if (!ratio)
return 0;
/*
* Calculate how many early kernel pages this group requires to
* satisfy the configured zone ratio.
*/
pages = group->present_movable_pages * 100 / ratio;
pages -= group->present_kernel_pages;
if (pages > 0)
stats->req_kernel_early_pages += pages;
stats->movable_pages += group->present_movable_pages;
return 0;
}
static bool auto_movable_can_online_movable(int nid, struct memory_group *group,
unsigned long nr_pages)
{
unsigned long kernel_early_pages, movable_pages;
struct auto_movable_group_stats group_stats = {};
struct auto_movable_stats stats = {};
pg_data_t *pgdat = NODE_DATA(nid);
struct zone *zone;
int i;
/* Walk all relevant zones and collect MOVABLE vs. KERNEL stats. */
if (nid == NUMA_NO_NODE) {
/* TODO: cache values */
for_each_populated_zone(zone)
auto_movable_stats_account_zone(&stats, zone);
} else {
for (i = 0; i < MAX_NR_ZONES; i++) {
zone = pgdat->node_zones + i;
if (populated_zone(zone))
auto_movable_stats_account_zone(&stats, zone);
}
}
kernel_early_pages = stats.kernel_early_pages;
movable_pages = stats.movable_pages;
/*
* Kernel memory inside dynamic memory group allows for more MOVABLE
* memory within the same group. Remove the effect of all but the
* current group from the stats.
*/
walk_dynamic_memory_groups(nid, auto_movable_stats_account_group,
group, &group_stats);
if (kernel_early_pages <= group_stats.req_kernel_early_pages)
return false;
kernel_early_pages -= group_stats.req_kernel_early_pages;
movable_pages -= group_stats.movable_pages;
if (group && group->is_dynamic)
kernel_early_pages += group->present_kernel_pages;
/*
* Test if we could online the given number of pages to ZONE_MOVABLE
* and still stay in the configured ratio.
*/
movable_pages += nr_pages;
return movable_pages <= (auto_movable_ratio * kernel_early_pages) / 100;
}
/*
* Returns a default kernel memory zone for the given pfn range.
* If no kernel zone covers this pfn range it will automatically go
* to the ZONE_NORMAL.
*/
static struct zone *default_kernel_zone_for_pfn(int nid, unsigned long start_pfn,
unsigned long nr_pages)
{
struct pglist_data *pgdat = NODE_DATA(nid);
int zid;
for (zid = 0; zid < ZONE_NORMAL; zid++) {
struct zone *zone = &pgdat->node_zones[zid];
if (zone_intersects(zone, start_pfn, nr_pages))
return zone;
}
return &pgdat->node_zones[ZONE_NORMAL];
}
/*
* Determine to which zone to online memory dynamically based on user
* configuration and system stats. We care about the following ratio:
*
* MOVABLE : KERNEL
*
* Whereby MOVABLE is memory in ZONE_MOVABLE and KERNEL is memory in
* one of the kernel zones. CMA pages inside one of the kernel zones really
* behaves like ZONE_MOVABLE, so we treat them accordingly.
*
* We don't allow for hotplugged memory in a KERNEL zone to increase the
* amount of MOVABLE memory we can have, so we end up with:
*
* MOVABLE : KERNEL_EARLY
*
* Whereby KERNEL_EARLY is memory in one of the kernel zones, available sinze
* boot. We base our calculation on KERNEL_EARLY internally, because:
*
* a) Hotplugged memory in one of the kernel zones can sometimes still get
* hotunplugged, especially when hot(un)plugging individual memory blocks.
* There is no coordination across memory devices, therefore "automatic"
* hotunplugging, as implemented in hypervisors, could result in zone
* imbalances.
* b) Early/boot memory in one of the kernel zones can usually not get
* hotunplugged again (e.g., no firmware interface to unplug, fragmented
* with unmovable allocations). While there are corner cases where it might
* still work, it is barely relevant in practice.
*
* Exceptions are dynamic memory groups, which allow for more MOVABLE
* memory within the same memory group -- because in that case, there is
* coordination within the single memory device managed by a single driver.
*
* We rely on "present pages" instead of "managed pages", as the latter is
* highly unreliable and dynamic in virtualized environments, and does not
* consider boot time allocations. For example, memory ballooning adjusts the
* managed pages when inflating/deflating the balloon, and balloon compaction
* can even migrate inflated pages between zones.
*
* Using "present pages" is better but some things to keep in mind are:
*
* a) Some memblock allocations, such as for the crashkernel area, are
* effectively unused by the kernel, yet they account to "present pages".
* Fortunately, these allocations are comparatively small in relevant setups
* (e.g., fraction of system memory).
* b) Some hotplugged memory blocks in virtualized environments, esecially
* hotplugged by virtio-mem, look like they are completely present, however,
* only parts of the memory block are actually currently usable.
* "present pages" is an upper limit that can get reached at runtime. As
* we base our calculations on KERNEL_EARLY, this is not an issue.
*/
static struct zone *auto_movable_zone_for_pfn(int nid,
struct memory_group *group,
unsigned long pfn,
unsigned long nr_pages)
{
unsigned long online_pages = 0, max_pages, end_pfn;
struct page *page;
if (!auto_movable_ratio)
goto kernel_zone;
if (group && !group->is_dynamic) {
max_pages = group->s.max_pages;
online_pages = group->present_movable_pages;
/* If anything is !MOVABLE online the rest !MOVABLE. */
if (group->present_kernel_pages)
goto kernel_zone;
} else if (!group || group->d.unit_pages == nr_pages) {
max_pages = nr_pages;
} else {
max_pages = group->d.unit_pages;
/*
* Take a look at all online sections in the current unit.
* We can safely assume that all pages within a section belong
* to the same zone, because dynamic memory groups only deal
* with hotplugged memory.
*/
pfn = ALIGN_DOWN(pfn, group->d.unit_pages);
end_pfn = pfn + group->d.unit_pages;
for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
page = pfn_to_online_page(pfn);
if (!page)
continue;
/* If anything is !MOVABLE online the rest !MOVABLE. */
if (!is_zone_movable_page(page))
goto kernel_zone;
online_pages += PAGES_PER_SECTION;
}
}
/*
* Online MOVABLE if we could *currently* online all remaining parts
* MOVABLE. We expect to (add+) online them immediately next, so if
* nobody interferes, all will be MOVABLE if possible.
*/
nr_pages = max_pages - online_pages;
if (!auto_movable_can_online_movable(NUMA_NO_NODE, group, nr_pages))
goto kernel_zone;
#ifdef CONFIG_NUMA
if (auto_movable_numa_aware &&
!auto_movable_can_online_movable(nid, group, nr_pages))
goto kernel_zone;
#endif /* CONFIG_NUMA */
return &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
kernel_zone:
return default_kernel_zone_for_pfn(nid, pfn, nr_pages);
}
static inline struct zone *default_zone_for_pfn(int nid, unsigned long start_pfn,
unsigned long nr_pages)
{
struct zone *kernel_zone = default_kernel_zone_for_pfn(nid, start_pfn,
nr_pages);
struct zone *movable_zone = &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
bool in_kernel = zone_intersects(kernel_zone, start_pfn, nr_pages);
bool in_movable = zone_intersects(movable_zone, start_pfn, nr_pages);
/*
* We inherit the existing zone in a simple case where zones do not
* overlap in the given range
*/
if (in_kernel ^ in_movable)
return (in_kernel) ? kernel_zone : movable_zone;
/*
* If the range doesn't belong to any zone or two zones overlap in the
* given range then we use movable zone only if movable_node is
* enabled because we always online to a kernel zone by default.
*/
return movable_node_enabled ? movable_zone : kernel_zone;
}
struct zone *zone_for_pfn_range(int online_type, int nid,
struct memory_group *group, unsigned long start_pfn,
unsigned long nr_pages)
{
if (online_type == MMOP_ONLINE_KERNEL)
return default_kernel_zone_for_pfn(nid, start_pfn, nr_pages);
if (online_type == MMOP_ONLINE_MOVABLE)
return &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
if (online_policy == ONLINE_POLICY_AUTO_MOVABLE)
return auto_movable_zone_for_pfn(nid, group, start_pfn, nr_pages);
return default_zone_for_pfn(nid, start_pfn, nr_pages);
}
/*
* This function should only be called by memory_block_{online,offline},
* and {online,offline}_pages.
*/
void adjust_present_page_count(struct page *page, struct memory_group *group,
long nr_pages)
{
struct zone *zone = page_zone(page);
const bool movable = zone_idx(zone) == ZONE_MOVABLE;
/*
* We only support onlining/offlining/adding/removing of complete
* memory blocks; therefore, either all is either early or hotplugged.
*/
if (early_section(__pfn_to_section(page_to_pfn(page))))
zone->present_early_pages += nr_pages;
zone->present_pages += nr_pages;
zone->zone_pgdat->node_present_pages += nr_pages;
if (group && movable)
group->present_movable_pages += nr_pages;
else if (group && !movable)
group->present_kernel_pages += nr_pages;
}
int mhp_init_memmap_on_memory(unsigned long pfn, unsigned long nr_pages,
struct zone *zone)
{
unsigned long end_pfn = pfn + nr_pages;
int ret, i;
ret = kasan_add_zero_shadow(__va(PFN_PHYS(pfn)), PFN_PHYS(nr_pages));
if (ret)
return ret;
move_pfn_range_to_zone(zone, pfn, nr_pages, NULL, MIGRATE_UNMOVABLE);
for (i = 0; i < nr_pages; i++)
SetPageVmemmapSelfHosted(pfn_to_page(pfn + i));
/*
* It might be that the vmemmap_pages fully span sections. If that is
* the case, mark those sections online here as otherwise they will be
* left offline.
*/
if (nr_pages >= PAGES_PER_SECTION)
online_mem_sections(pfn, ALIGN_DOWN(end_pfn, PAGES_PER_SECTION));
return ret;
}
void mhp_deinit_memmap_on_memory(unsigned long pfn, unsigned long nr_pages)
{
unsigned long end_pfn = pfn + nr_pages;
/*
* It might be that the vmemmap_pages fully span sections. If that is
* the case, mark those sections offline here as otherwise they will be
* left online.
*/
if (nr_pages >= PAGES_PER_SECTION)
offline_mem_sections(pfn, ALIGN_DOWN(end_pfn, PAGES_PER_SECTION));
/*
* The pages associated with this vmemmap have been offlined, so
* we can reset its state here.
*/
remove_pfn_range_from_zone(page_zone(pfn_to_page(pfn)), pfn, nr_pages);
kasan_remove_zero_shadow(__va(PFN_PHYS(pfn)), PFN_PHYS(nr_pages));
}
int __ref online_pages(unsigned long pfn, unsigned long nr_pages,
struct zone *zone, struct memory_group *group)
{
unsigned long flags;
int need_zonelists_rebuild = 0;
const int nid = zone_to_nid(zone);
int ret;
struct memory_notify arg;
/*
* {on,off}lining is constrained to full memory sections (or more
* precisely to memory blocks from the user space POV).
* memmap_on_memory is an exception because it reserves initial part
* of the physical memory space for vmemmaps. That space is pageblock
* aligned.
*/
if (WARN_ON_ONCE(!nr_pages || !pageblock_aligned(pfn) ||
!IS_ALIGNED(pfn + nr_pages, PAGES_PER_SECTION)))
return -EINVAL;
mem_hotplug_begin();
/* associate pfn range with the zone */
move_pfn_range_to_zone(zone, pfn, nr_pages, NULL, MIGRATE_ISOLATE);
arg.start_pfn = pfn;
arg.nr_pages = nr_pages;
node_states_check_changes_online(nr_pages, zone, &arg);
ret = memory_notify(MEM_GOING_ONLINE, &arg);
ret = notifier_to_errno(ret);
if (ret)
goto failed_addition;
/*
* Fixup the number of isolated pageblocks before marking the sections
* onlining, such that undo_isolate_page_range() works correctly.
*/
spin_lock_irqsave(&zone->lock, flags);
zone->nr_isolate_pageblock += nr_pages / pageblock_nr_pages;
spin_unlock_irqrestore(&zone->lock, flags);
/*
* If this zone is not populated, then it is not in zonelist.
* This means the page allocator ignores this zone.
* So, zonelist must be updated after online.
*/
if (!populated_zone(zone)) {
need_zonelists_rebuild = 1;
setup_zone_pageset(zone);
}
online_pages_range(pfn, nr_pages);
adjust_present_page_count(pfn_to_page(pfn), group, nr_pages);
node_states_set_node(nid, &arg);
if (need_zonelists_rebuild)
build_all_zonelists(NULL);
/* Basic onlining is complete, allow allocation of onlined pages. */
undo_isolate_page_range(pfn, pfn + nr_pages, MIGRATE_MOVABLE);
/*
* Freshly onlined pages aren't shuffled (e.g., all pages are placed to
* the tail of the freelist when undoing isolation). Shuffle the whole
* zone to make sure the just onlined pages are properly distributed
* across the whole freelist - to create an initial shuffle.
*/
shuffle_zone(zone);
/* reinitialise watermarks and update pcp limits */
init_per_zone_wmark_min();
kswapd_run(nid);
kcompactd_run(nid);
writeback_set_ratelimit();
memory_notify(MEM_ONLINE, &arg);
mem_hotplug_done();
return 0;
failed_addition:
pr_debug("online_pages [mem %#010llx-%#010llx] failed\n",
(unsigned long long) pfn << PAGE_SHIFT,
(((unsigned long long) pfn + nr_pages) << PAGE_SHIFT) - 1);
memory_notify(MEM_CANCEL_ONLINE, &arg);
remove_pfn_range_from_zone(zone, pfn, nr_pages);
mem_hotplug_done();
return ret;
}
/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
static pg_data_t __ref *hotadd_init_pgdat(int nid)
{
struct pglist_data *pgdat;
/*
* NODE_DATA is preallocated (free_area_init) but its internal
* state is not allocated completely. Add missing pieces.
* Completely offline nodes stay around and they just need
* reintialization.
*/
pgdat = NODE_DATA(nid);
/* init node's zones as empty zones, we don't have any present pages.*/
free_area_init_core_hotplug(pgdat);
/*
* The node we allocated has no zone fallback lists. For avoiding
* to access not-initialized zonelist, build here.
*/
build_all_zonelists(pgdat);
return pgdat;
}
/*
* __try_online_node - online a node if offlined
* @nid: the node ID
* @set_node_online: Whether we want to online the node
* called by cpu_up() to online a node without onlined memory.
*
* Returns:
* 1 -> a new node has been allocated
* 0 -> the node is already online
* -ENOMEM -> the node could not be allocated
*/
static int __try_online_node(int nid, bool set_node_online)
{
pg_data_t *pgdat;
int ret = 1;
if (node_online(nid))
return 0;
pgdat = hotadd_init_pgdat(nid);
if (!pgdat) {
pr_err("Cannot online node %d due to NULL pgdat\n", nid);
ret = -ENOMEM;
goto out;
}
if (set_node_online) {
node_set_online(nid);
ret = register_one_node(nid);
BUG_ON(ret);
}
out:
return ret;
}
/*
* Users of this function always want to online/register the node
*/
int try_online_node(int nid)
{
int ret;
mem_hotplug_begin();
ret = __try_online_node(nid, true);
mem_hotplug_done();
return ret;
}
static int check_hotplug_memory_range(u64 start, u64 size)
{
/* memory range must be block size aligned */
if (!size || !IS_ALIGNED(start, memory_block_size_bytes()) ||
!IS_ALIGNED(size, memory_block_size_bytes())) {
pr_err("Block size [%#lx] unaligned hotplug range: start %#llx, size %#llx",
memory_block_size_bytes(), start, size);
return -EINVAL;
}
return 0;
}
static int online_memory_block(struct memory_block *mem, void *arg)
{
mem->online_type = mhp_default_online_type;
return device_online(&mem->dev);
}
#ifndef arch_supports_memmap_on_memory
static inline bool arch_supports_memmap_on_memory(unsigned long vmemmap_size)
{
/*
* As default, we want the vmemmap to span a complete PMD such that we
* can map the vmemmap using a single PMD if supported by the
* architecture.
*/
return IS_ALIGNED(vmemmap_size, PMD_SIZE);
}
#endif
static bool mhp_supports_memmap_on_memory(unsigned long size)
{
unsigned long vmemmap_size = memory_block_memmap_size();
unsigned long memmap_pages = memory_block_memmap_on_memory_pages();
/*
* Besides having arch support and the feature enabled at runtime, we
* need a few more assumptions to hold true:
*
* a) We span a single memory block: memory onlining/offlinin;g happens
* in memory block granularity. We don't want the vmemmap of online
* memory blocks to reside on offline memory blocks. In the future,
* we might want to support variable-sized memory blocks to make the
* feature more versatile.
*
* b) The vmemmap pages span complete PMDs: We don't want vmemmap code
* to populate memory from the altmap for unrelated parts (i.e.,
* other memory blocks)
*
* c) The vmemmap pages (and thereby the pages that will be exposed to
* the buddy) have to cover full pageblocks: memory onlining/offlining
* code requires applicable ranges to be page-aligned, for example, to
* set the migratetypes properly.
*
* TODO: Although we have a check here to make sure that vmemmap pages
* fully populate a PMD, it is not the right place to check for
* this. A much better solution involves improving vmemmap code
* to fallback to base pages when trying to populate vmemmap using
* altmap as an alternative source of memory, and we do not exactly
* populate a single PMD.
*/
if (!mhp_memmap_on_memory() || size != memory_block_size_bytes())
return false;
/*
* Make sure the vmemmap allocation is fully contained
* so that we always allocate vmemmap memory from altmap area.
*/
if (!IS_ALIGNED(vmemmap_size, PAGE_SIZE))
return false;
/*
* start pfn should be pageblock_nr_pages aligned for correctly
* setting migrate types
*/
if (!pageblock_aligned(memmap_pages))
return false;
if (memmap_pages == PHYS_PFN(memory_block_size_bytes()))
/* No effective hotplugged memory doesn't make sense. */
return false;
return arch_supports_memmap_on_memory(vmemmap_size);
}
/*
* NOTE: The caller must call lock_device_hotplug() to serialize hotplug
* and online/offline operations (triggered e.g. by sysfs).
*
* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG
*/
int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags)
{
struct mhp_params params = { .pgprot = pgprot_mhp(PAGE_KERNEL) };
enum memblock_flags memblock_flags = MEMBLOCK_NONE;
struct vmem_altmap mhp_altmap = {
.base_pfn = PHYS_PFN(res->start),
.end_pfn = PHYS_PFN(res->end),
};
struct memory_group *group = NULL;
u64 start, size;
bool new_node = false;
int ret;
start = res->start;
size = resource_size(res);
ret = check_hotplug_memory_range(start, size);
if (ret)
return ret;
if (mhp_flags & MHP_NID_IS_MGID) {
group = memory_group_find_by_id(nid);
if (!group)
return -EINVAL;
nid = group->nid;
}
if (!node_possible(nid)) {
WARN(1, "node %d was absent from the node_possible_map\n", nid);
return -EINVAL;
}
mem_hotplug_begin();
if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) {
if (res->flags & IORESOURCE_SYSRAM_DRIVER_MANAGED)
memblock_flags = MEMBLOCK_DRIVER_MANAGED;
ret = memblock_add_node(start, size, nid, memblock_flags);
if (ret)
goto error_mem_hotplug_end;
}
ret = __try_online_node(nid, false);
if (ret < 0)
goto error;
new_node = ret;
/*
* Self hosted memmap array
*/
if (mhp_flags & MHP_MEMMAP_ON_MEMORY) {
if (mhp_supports_memmap_on_memory(size)) {
mhp_altmap.free = memory_block_memmap_on_memory_pages();
params.altmap = kmalloc(sizeof(struct vmem_altmap), GFP_KERNEL);
if (!params.altmap) {
ret = -ENOMEM;
goto error;
}
memcpy(params.altmap, &mhp_altmap, sizeof(mhp_altmap));
}
/* fallback to not using altmap */
}
/* call arch's memory hotadd */
ret = arch_add_memory(nid, start, size, ¶ms);
if (ret < 0)
goto error_free;
/* create memory block devices after memory was added */
ret = create_memory_block_devices(start, size, params.altmap, group);
if (ret) {
arch_remove_memory(start, size, NULL);
goto error_free;
}
if (new_node) {
/* If sysfs file of new node can't be created, cpu on the node
* can't be hot-added. There is no rollback way now.
* So, check by BUG_ON() to catch it reluctantly..
* We online node here. We can't roll back from here.
*/
node_set_online(nid);
ret = __register_one_node(nid);
BUG_ON(ret);
}
register_memory_blocks_under_node(nid, PFN_DOWN(start),
PFN_UP(start + size - 1),
MEMINIT_HOTPLUG);
/* create new memmap entry */
if (!strcmp(res->name, "System RAM"))
firmware_map_add_hotplug(start, start + size, "System RAM");
/* device_online() will take the lock when calling online_pages() */
mem_hotplug_done();
/*
* In case we're allowed to merge the resource, flag it and trigger
* merging now that adding succeeded.
*/
if (mhp_flags & MHP_MERGE_RESOURCE)
merge_system_ram_resource(res);
/* online pages if requested */
if (mhp_default_online_type != MMOP_OFFLINE)
walk_memory_blocks(start, size, NULL, online_memory_block);
return ret;
error_free:
kfree(params.altmap);
error:
if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
memblock_remove(start, size);
error_mem_hotplug_end:
mem_hotplug_done();
return ret;
}
/* requires device_hotplug_lock, see add_memory_resource() */
int __ref __add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags)
{
struct resource *res;
int ret;
res = register_memory_resource(start, size, "System RAM");
if (IS_ERR(res))
return PTR_ERR(res);
ret = add_memory_resource(nid, res, mhp_flags);
if (ret < 0)
release_memory_resource(res);
return ret;
}
int add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags)
{
int rc;
lock_device_hotplug();
rc = __add_memory(nid, start, size, mhp_flags);
unlock_device_hotplug();
return rc;
}
EXPORT_SYMBOL_GPL(add_memory);
/*
* Add special, driver-managed memory to the system as system RAM. Such
* memory is not exposed via the raw firmware-provided memmap as system
* RAM, instead, it is detected and added by a driver - during cold boot,
* after a reboot, and after kexec.
*
* Reasons why this memory should not be used for the initial memmap of a
* kexec kernel or for placing kexec images:
* - The booting kernel is in charge of determining how this memory will be
* used (e.g., use persistent memory as system RAM)
* - Coordination with a hypervisor is required before this memory
* can be used (e.g., inaccessible parts).
*
* For this memory, no entries in /sys/firmware/memmap ("raw firmware-provided
* memory map") are created. Also, the created memory resource is flagged
* with IORESOURCE_SYSRAM_DRIVER_MANAGED, so in-kernel users can special-case
* this memory as well (esp., not place kexec images onto it).
*
* The resource_name (visible via /proc/iomem) has to have the format
* "System RAM ($DRIVER)".
*/
int add_memory_driver_managed(int nid, u64 start, u64 size,
const char *resource_name, mhp_t mhp_flags)
{
struct resource *res;
int rc;
if (!resource_name ||
strstr(resource_name, "System RAM (") != resource_name ||
resource_name[strlen(resource_name) - 1] != ')')
return -EINVAL;
lock_device_hotplug();
res = register_memory_resource(start, size, resource_name);
if (IS_ERR(res)) {
rc = PTR_ERR(res);
goto out_unlock;
}
rc = add_memory_resource(nid, res, mhp_flags);
if (rc < 0)
release_memory_resource(res);
out_unlock:
unlock_device_hotplug();
return rc;
}
EXPORT_SYMBOL_GPL(add_memory_driver_managed);
/*
* Platforms should define arch_get_mappable_range() that provides
* maximum possible addressable physical memory range for which the
* linear mapping could be created. The platform returned address
* range must adhere to these following semantics.
*
* - range.start <= range.end
* - Range includes both end points [range.start..range.end]
*
* There is also a fallback definition provided here, allowing the
* entire possible physical address range in case any platform does
* not define arch_get_mappable_range().
*/
struct range __weak arch_get_mappable_range(void)
{
struct range mhp_range = {
.start = 0UL,
.end = -1ULL,
};
return mhp_range;
}
struct range mhp_get_pluggable_range(bool need_mapping)
{
const u64 max_phys = (1ULL << MAX_PHYSMEM_BITS) - 1;
struct range mhp_range;
if (need_mapping) {
mhp_range = arch_get_mappable_range();
if (mhp_range.start > max_phys) {
mhp_range.start = 0;
mhp_range.end = 0;
}
mhp_range.end = min_t(u64, mhp_range.end, max_phys);
} else {
mhp_range.start = 0;
mhp_range.end = max_phys;
}
return mhp_range;
}
EXPORT_SYMBOL_GPL(mhp_get_pluggable_range);
bool mhp_range_allowed(u64 start, u64 size, bool need_mapping)
{
struct range mhp_range = mhp_get_pluggable_range(need_mapping);
u64 end = start + size;
if (start < end && start >= mhp_range.start && (end - 1) <= mhp_range.end)
return true;
pr_warn("Hotplug memory [%#llx-%#llx] exceeds maximum addressable range [%#llx-%#llx]\n",
start, end, mhp_range.start, mhp_range.end);
return false;
}
#ifdef CONFIG_MEMORY_HOTREMOVE
/*
* Scan pfn range [start,end) to find movable/migratable pages (LRU pages,
* non-lru movable pages and hugepages). Will skip over most unmovable
* pages (esp., pages that can be skipped when offlining), but bail out on
* definitely unmovable pages.
*
* Returns:
* 0 in case a movable page is found and movable_pfn was updated.
* -ENOENT in case no movable page was found.
* -EBUSY in case a definitely unmovable page was found.
*/
static int scan_movable_pages(unsigned long start, unsigned long end,
unsigned long *movable_pfn)
{
unsigned long pfn;
for (pfn = start; pfn < end; pfn++) {
struct page *page, *head;
unsigned long skip;
if (!pfn_valid(pfn))
continue;
page = pfn_to_page(pfn);
if (PageLRU(page))
goto found;
if (__PageMovable(page))
goto found;
/*
* PageOffline() pages that are not marked __PageMovable() and
* have a reference count > 0 (after MEM_GOING_OFFLINE) are
* definitely unmovable. If their reference count would be 0,
* they could at least be skipped when offlining memory.
*/
if (PageOffline(page) && page_count(page))
return -EBUSY;
if (!PageHuge(page))
continue;
head = compound_head(page);
/*
* This test is racy as we hold no reference or lock. The
* hugetlb page could have been free'ed and head is no longer
* a hugetlb page before the following check. In such unlikely
* cases false positives and negatives are possible. Calling
* code must deal with these scenarios.
*/
if (HPageMigratable(head))
goto found;
skip = compound_nr(head) - (page - head);
pfn += skip - 1;
}
return -ENOENT;
found:
*movable_pfn = pfn;
return 0;
}
static void do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
{
unsigned long pfn;
struct page *page, *head;
LIST_HEAD(source);
static DEFINE_RATELIMIT_STATE(migrate_rs, DEFAULT_RATELIMIT_INTERVAL,
DEFAULT_RATELIMIT_BURST);
for (pfn = start_pfn; pfn < end_pfn; pfn++) {
struct folio *folio;
bool isolated;
if (!pfn_valid(pfn))
continue;
page = pfn_to_page(pfn);
folio = page_folio(page);
head = &folio->page;
if (PageHuge(page)) {
pfn = page_to_pfn(head) + compound_nr(head) - 1;
isolate_hugetlb(folio, &source);
continue;
} else if (PageTransHuge(page))
pfn = page_to_pfn(head) + thp_nr_pages(page) - 1;
/*
* HWPoison pages have elevated reference counts so the migration would
* fail on them. It also doesn't make any sense to migrate them in the
* first place. Still try to unmap such a page in case it is still mapped
* (e.g. current hwpoison implementation doesn't unmap KSM pages but keep
* the unmap as the catch all safety net).
*/
if (PageHWPoison(page)) {
if (WARN_ON(folio_test_lru(folio)))
folio_isolate_lru(folio);
if (folio_mapped(folio))
try_to_unmap(folio, TTU_IGNORE_MLOCK);
continue;
}
if (!get_page_unless_zero(page))
continue;
/*
* We can skip free pages. And we can deal with pages on
* LRU and non-lru movable pages.
*/
if (PageLRU(page))
isolated = isolate_lru_page(page);
else
isolated = isolate_movable_page(page, ISOLATE_UNEVICTABLE);
if (isolated) {
list_add_tail(&page->lru, &source);
if (!__PageMovable(page))
inc_node_page_state(page, NR_ISOLATED_ANON +
page_is_file_lru(page));
} else {
if (__ratelimit(&migrate_rs)) {
pr_warn("failed to isolate pfn %lx\n", pfn);
dump_page(page, "isolation failed");
}
}
put_page(page);
}
if (!list_empty(&source)) {
nodemask_t nmask = node_states[N_MEMORY];
struct migration_target_control mtc = {
.nmask = &nmask,
.gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL,
};
int ret;
/*
* We have checked that migration range is on a single zone so
* we can use the nid of the first page to all the others.
*/
mtc.nid = page_to_nid(list_first_entry(&source, struct page, lru));
/*
* try to allocate from a different node but reuse this node
* if there are no other online nodes to be used (e.g. we are
* offlining a part of the only existing node)
*/
node_clear(mtc.nid, nmask);
if (nodes_empty(nmask))
node_set(mtc.nid, nmask);
ret = migrate_pages(&source, alloc_migration_target, NULL,
(unsigned long)&mtc, MIGRATE_SYNC, MR_MEMORY_HOTPLUG, NULL);
if (ret) {
list_for_each_entry(page, &source, lru) {
if (__ratelimit(&migrate_rs)) {
pr_warn("migrating pfn %lx failed ret:%d\n",
page_to_pfn(page), ret);
dump_page(page, "migration failure");
}
}
putback_movable_pages(&source);
}
}
}
static int __init cmdline_parse_movable_node(char *p)
{
movable_node_enabled = true;
return 0;
}
early_param("movable_node", cmdline_parse_movable_node);
/* check which state of node_states will be changed when offline memory */
static void node_states_check_changes_offline(unsigned long nr_pages,
struct zone *zone, struct memory_notify *arg)
{
struct pglist_data *pgdat = zone->zone_pgdat;
unsigned long present_pages = 0;
enum zone_type zt;
arg->status_change_nid = NUMA_NO_NODE;
arg->status_change_nid_normal = NUMA_NO_NODE;
/*
* Check whether node_states[N_NORMAL_MEMORY] will be changed.
* If the memory to be offline is within the range
* [0..ZONE_NORMAL], and it is the last present memory there,
* the zones in that range will become empty after the offlining,
* thus we can determine that we need to clear the node from
* node_states[N_NORMAL_MEMORY].
*/
for (zt = 0; zt <= ZONE_NORMAL; zt++)
present_pages += pgdat->node_zones[zt].present_pages;
if (zone_idx(zone) <= ZONE_NORMAL && nr_pages >= present_pages)
arg->status_change_nid_normal = zone_to_nid(zone);
/*
* We have accounted the pages from [0..ZONE_NORMAL); ZONE_HIGHMEM
* does not apply as we don't support 32bit.
* Here we count the possible pages from ZONE_MOVABLE.
* If after having accounted all the pages, we see that the nr_pages
* to be offlined is over or equal to the accounted pages,
* we know that the node will become empty, and so, we can clear
* it for N_MEMORY as well.
*/
present_pages += pgdat->node_zones[ZONE_MOVABLE].present_pages;
if (nr_pages >= present_pages)
arg->status_change_nid = zone_to_nid(zone);
}
static void node_states_clear_node(int node, struct memory_notify *arg)
{
if (arg->status_change_nid_normal >= 0)
node_clear_state(node, N_NORMAL_MEMORY);
if (arg->status_change_nid >= 0)
node_clear_state(node, N_MEMORY);
}
static int count_system_ram_pages_cb(unsigned long start_pfn,
unsigned long nr_pages, void *data)
{
unsigned long *nr_system_ram_pages = data;
*nr_system_ram_pages += nr_pages;
return 0;
}
int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages,
struct zone *zone, struct memory_group *group)
{
const unsigned long end_pfn = start_pfn + nr_pages;
unsigned long pfn, system_ram_pages = 0;
const int node = zone_to_nid(zone);
unsigned long flags;
struct memory_notify arg;
char *reason;
int ret;
/*
* {on,off}lining is constrained to full memory sections (or more
* precisely to memory blocks from the user space POV).
* memmap_on_memory is an exception because it reserves initial part
* of the physical memory space for vmemmaps. That space is pageblock
* aligned.
*/
if (WARN_ON_ONCE(!nr_pages || !pageblock_aligned(start_pfn) ||
!IS_ALIGNED(start_pfn + nr_pages, PAGES_PER_SECTION)))
return -EINVAL;
mem_hotplug_begin();
/*
* Don't allow to offline memory blocks that contain holes.
* Consequently, memory blocks with holes can never get onlined
* via the hotplug path - online_pages() - as hotplugged memory has
* no holes. This way, we e.g., don't have to worry about marking
* memory holes PG_reserved, don't need pfn_valid() checks, and can
* avoid using walk_system_ram_range() later.
*/
walk_system_ram_range(start_pfn, nr_pages, &system_ram_pages,
count_system_ram_pages_cb);
if (system_ram_pages != nr_pages) {
ret = -EINVAL;
reason = "memory holes";
goto failed_removal;
}
/*
* We only support offlining of memory blocks managed by a single zone,
* checked by calling code. This is just a sanity check that we might
* want to remove in the future.
*/
if (WARN_ON_ONCE(page_zone(pfn_to_page(start_pfn)) != zone ||
page_zone(pfn_to_page(end_pfn - 1)) != zone)) {
ret = -EINVAL;
reason = "multizone range";
goto failed_removal;
}
/*
* Disable pcplists so that page isolation cannot race with freeing
* in a way that pages from isolated pageblock are left on pcplists.
*/
zone_pcp_disable(zone);
lru_cache_disable();
/* set above range as isolated */
ret = start_isolate_page_range(start_pfn, end_pfn,
MIGRATE_MOVABLE,
MEMORY_OFFLINE | REPORT_FAILURE,
GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL);
if (ret) {
reason = "failure to isolate range";
goto failed_removal_pcplists_disabled;
}
arg.start_pfn = start_pfn;
arg.nr_pages = nr_pages;
node_states_check_changes_offline(nr_pages, zone, &arg);
ret = memory_notify(MEM_GOING_OFFLINE, &arg);
ret = notifier_to_errno(ret);
if (ret) {
reason = "notifier failure";
goto failed_removal_isolated;
}
do {
pfn = start_pfn;
do {
/*
* Historically we always checked for any signal and
* can't limit it to fatal signals without eventually
* breaking user space.
*/
if (signal_pending(current)) {
ret = -EINTR;
reason = "signal backoff";
goto failed_removal_isolated;
}
cond_resched();
ret = scan_movable_pages(pfn, end_pfn, &pfn);
if (!ret) {
/*
* TODO: fatal migration failures should bail
* out
*/
do_migrate_range(pfn, end_pfn);
}
} while (!ret);
if (ret != -ENOENT) {
reason = "unmovable page";
goto failed_removal_isolated;
}
/*
* Dissolve free hugepages in the memory block before doing
* offlining actually in order to make hugetlbfs's object
* counting consistent.
*/
ret = dissolve_free_huge_pages(start_pfn, end_pfn);
if (ret) {
reason = "failure to dissolve huge pages";
goto failed_removal_isolated;
}
ret = test_pages_isolated(start_pfn, end_pfn, MEMORY_OFFLINE);
} while (ret);
/* Mark all sections offline and remove free pages from the buddy. */
__offline_isolated_pages(start_pfn, end_pfn);
pr_debug("Offlined Pages %ld\n", nr_pages);
/*
* The memory sections are marked offline, and the pageblock flags
* effectively stale; nobody should be touching them. Fixup the number
* of isolated pageblocks, memory onlining will properly revert this.
*/
spin_lock_irqsave(&zone->lock, flags);
zone->nr_isolate_pageblock -= nr_pages / pageblock_nr_pages;
spin_unlock_irqrestore(&zone->lock, flags);
lru_cache_enable();
zone_pcp_enable(zone);
/* removal success */
adjust_managed_page_count(pfn_to_page(start_pfn), -nr_pages);
adjust_present_page_count(pfn_to_page(start_pfn), group, -nr_pages);
/* reinitialise watermarks and update pcp limits */
init_per_zone_wmark_min();
if (!populated_zone(zone)) {
zone_pcp_reset(zone);
build_all_zonelists(NULL);
}
node_states_clear_node(node, &arg);
if (arg.status_change_nid >= 0) {
kcompactd_stop(node);
kswapd_stop(node);
}
writeback_set_ratelimit();
memory_notify(MEM_OFFLINE, &arg);
remove_pfn_range_from_zone(zone, start_pfn, nr_pages);
mem_hotplug_done();
return 0;
failed_removal_isolated:
/* pushback to free area */
undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
memory_notify(MEM_CANCEL_OFFLINE, &arg);
failed_removal_pcplists_disabled:
lru_cache_enable();
zone_pcp_enable(zone);
failed_removal:
pr_debug("memory offlining [mem %#010llx-%#010llx] failed due to %s\n",
(unsigned long long) start_pfn << PAGE_SHIFT,
((unsigned long long) end_pfn << PAGE_SHIFT) - 1,
reason);
mem_hotplug_done();
return ret;
}
static int check_memblock_offlined_cb(struct memory_block *mem, void *arg)
{
int *nid = arg;
*nid = mem->nid;
if (unlikely(mem->state != MEM_OFFLINE)) {
phys_addr_t beginpa, endpa;
beginpa = PFN_PHYS(section_nr_to_pfn(mem->start_section_nr));
endpa = beginpa + memory_block_size_bytes() - 1;
pr_warn("removing memory fails, because memory [%pa-%pa] is onlined\n",
&beginpa, &endpa);
return -EBUSY;
}
return 0;
}
static int test_has_altmap_cb(struct memory_block *mem, void *arg)
{
struct memory_block **mem_ptr = (struct memory_block **)arg;
/*
* return the memblock if we have altmap
* and break callback.
*/
if (mem->altmap) {
*mem_ptr = mem;
return 1;
}
return 0;
}
static int check_cpu_on_node(int nid)
{
int cpu;
for_each_present_cpu(cpu) {
if (cpu_to_node(cpu) == nid)
/*
* the cpu on this node isn't removed, and we can't
* offline this node.
*/
return -EBUSY;
}
return 0;
}
static int check_no_memblock_for_node_cb(struct memory_block *mem, void *arg)
{
int nid = *(int *)arg;
/*
* If a memory block belongs to multiple nodes, the stored nid is not
* reliable. However, such blocks are always online (e.g., cannot get
* offlined) and, therefore, are still spanned by the node.
*/
return mem->nid == nid ? -EEXIST : 0;
}
/**
* try_offline_node
* @nid: the node ID
*
* Offline a node if all memory sections and cpus of the node are removed.
*
* NOTE: The caller must call lock_device_hotplug() to serialize hotplug
* and online/offline operations before this call.
*/
void try_offline_node(int nid)
{
int rc;
/*
* If the node still spans pages (especially ZONE_DEVICE), don't
* offline it. A node spans memory after move_pfn_range_to_zone(),
* e.g., after the memory block was onlined.
*/
if (node_spanned_pages(nid))
return;
/*
* Especially offline memory blocks might not be spanned by the
* node. They will get spanned by the node once they get onlined.
* However, they link to the node in sysfs and can get onlined later.
*/
rc = for_each_memory_block(&nid, check_no_memblock_for_node_cb);
if (rc)
return;
if (check_cpu_on_node(nid))
return;
/*
* all memory/cpu of this node are removed, we can offline this
* node now.
*/
node_set_offline(nid);
unregister_one_node(nid);
}
EXPORT_SYMBOL(try_offline_node);
static int __ref try_remove_memory(u64 start, u64 size)
{
struct memory_block *mem;
int rc = 0, nid = NUMA_NO_NODE;
struct vmem_altmap *altmap = NULL;
BUG_ON(check_hotplug_memory_range(start, size));
/*
* All memory blocks must be offlined before removing memory. Check
* whether all memory blocks in question are offline and return error
* if this is not the case.
*
* While at it, determine the nid. Note that if we'd have mixed nodes,
* we'd only try to offline the last determined one -- which is good
* enough for the cases we care about.
*/
rc = walk_memory_blocks(start, size, &nid, check_memblock_offlined_cb);
if (rc)
return rc;
/*
* We only support removing memory added with MHP_MEMMAP_ON_MEMORY in
* the same granularity it was added - a single memory block.
*/
if (mhp_memmap_on_memory()) {
rc = walk_memory_blocks(start, size, &mem, test_has_altmap_cb);
if (rc) {
if (size != memory_block_size_bytes()) {
pr_warn("Refuse to remove %#llx - %#llx,"
"wrong granularity\n",
start, start + size);
return -EINVAL;
}
altmap = mem->altmap;
/*
* Mark altmap NULL so that we can add a debug
* check on memblock free.
*/
mem->altmap = NULL;
}
}
/* remove memmap entry */
firmware_map_remove(start, start + size, "System RAM");
/*
* Memory block device removal under the device_hotplug_lock is
* a barrier against racing online attempts.
*/
remove_memory_block_devices(start, size);
mem_hotplug_begin();
arch_remove_memory(start, size, altmap);
/* Verify that all vmemmap pages have actually been freed. */
if (altmap) {
WARN(altmap->alloc, "Altmap not fully unmapped");
kfree(altmap);
}
if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) {
memblock_phys_free(start, size);
memblock_remove(start, size);
}
release_mem_region_adjustable(start, size);
if (nid != NUMA_NO_NODE)
try_offline_node(nid);
mem_hotplug_done();
return 0;
}
/**
* __remove_memory - Remove memory if every memory block is offline
* @start: physical address of the region to remove
* @size: size of the region to remove
*
* NOTE: The caller must call lock_device_hotplug() to serialize hotplug
* and online/offline operations before this call, as required by
* try_offline_node().
*/
void __remove_memory(u64 start, u64 size)
{
/*
* trigger BUG() if some memory is not offlined prior to calling this
* function
*/
if (try_remove_memory(start, size))
BUG();
}
/*
* Remove memory if every memory block is offline, otherwise return -EBUSY is
* some memory is not offline
*/
int remove_memory(u64 start, u64 size)
{
int rc;
lock_device_hotplug();
rc = try_remove_memory(start, size);
unlock_device_hotplug();
return rc;
}
EXPORT_SYMBOL_GPL(remove_memory);
static int try_offline_memory_block(struct memory_block *mem, void *arg)
{
uint8_t online_type = MMOP_ONLINE_KERNEL;
uint8_t **online_types = arg;
struct page *page;
int rc;
/*
* Sense the online_type via the zone of the memory block. Offlining
* with multiple zones within one memory block will be rejected
* by offlining code ... so we don't care about that.
*/
page = pfn_to_online_page(section_nr_to_pfn(mem->start_section_nr));
if (page && zone_idx(page_zone(page)) == ZONE_MOVABLE)
online_type = MMOP_ONLINE_MOVABLE;
rc = device_offline(&mem->dev);
/*
* Default is MMOP_OFFLINE - change it only if offlining succeeded,
* so try_reonline_memory_block() can do the right thing.
*/
if (!rc)
**online_types = online_type;
(*online_types)++;
/* Ignore if already offline. */
return rc < 0 ? rc : 0;
}
static int try_reonline_memory_block(struct memory_block *mem, void *arg)
{
uint8_t **online_types = arg;
int rc;
if (**online_types != MMOP_OFFLINE) {
mem->online_type = **online_types;
rc = device_online(&mem->dev);
if (rc < 0)
pr_warn("%s: Failed to re-online memory: %d",
__func__, rc);
}
/* Continue processing all remaining memory blocks. */
(*online_types)++;
return 0;
}
/*
* Try to offline and remove memory. Might take a long time to finish in case
* memory is still in use. Primarily useful for memory devices that logically
* unplugged all memory (so it's no longer in use) and want to offline + remove
* that memory.
*/
int offline_and_remove_memory(u64 start, u64 size)
{
const unsigned long mb_count = size / memory_block_size_bytes();
uint8_t *online_types, *tmp;
int rc;
if (!IS_ALIGNED(start, memory_block_size_bytes()) ||
!IS_ALIGNED(size, memory_block_size_bytes()) || !size)
return -EINVAL;
/*
* We'll remember the old online type of each memory block, so we can
* try to revert whatever we did when offlining one memory block fails
* after offlining some others succeeded.
*/
online_types = kmalloc_array(mb_count, sizeof(*online_types),
GFP_KERNEL);
if (!online_types)
return -ENOMEM;
/*
* Initialize all states to MMOP_OFFLINE, so when we abort processing in
* try_offline_memory_block(), we'll skip all unprocessed blocks in
* try_reonline_memory_block().
*/
memset(online_types, MMOP_OFFLINE, mb_count);
lock_device_hotplug();
tmp = online_types;
rc = walk_memory_blocks(start, size, &tmp, try_offline_memory_block);
/*
* In case we succeeded to offline all memory, remove it.
* This cannot fail as it cannot get onlined in the meantime.
*/
if (!rc) {
rc = try_remove_memory(start, size);
if (rc)
pr_err("%s: Failed to remove memory: %d", __func__, rc);
}
/*
* Rollback what we did. While memory onlining might theoretically fail
* (nacked by a notifier), it barely ever happens.
*/
if (rc) {
tmp = online_types;
walk_memory_blocks(start, size, &tmp,
try_reonline_memory_block);
}
unlock_device_hotplug();
kfree(online_types);
return rc;
}
EXPORT_SYMBOL_GPL(offline_and_remove_memory);
#endif /* CONFIG_MEMORY_HOTREMOVE */
| linux-master | mm/memory_hotplug.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2021, Google LLC.
* Pasha Tatashin <[email protected]>
*/
#include <linux/kstrtox.h>
#include <linux/mm.h>
#include <linux/page_table_check.h>
#undef pr_fmt
#define pr_fmt(fmt) "page_table_check: " fmt
struct page_table_check {
atomic_t anon_map_count;
atomic_t file_map_count;
};
static bool __page_table_check_enabled __initdata =
IS_ENABLED(CONFIG_PAGE_TABLE_CHECK_ENFORCED);
DEFINE_STATIC_KEY_TRUE(page_table_check_disabled);
EXPORT_SYMBOL(page_table_check_disabled);
static int __init early_page_table_check_param(char *buf)
{
return kstrtobool(buf, &__page_table_check_enabled);
}
early_param("page_table_check", early_page_table_check_param);
static bool __init need_page_table_check(void)
{
return __page_table_check_enabled;
}
static void __init init_page_table_check(void)
{
if (!__page_table_check_enabled)
return;
static_branch_disable(&page_table_check_disabled);
}
struct page_ext_operations page_table_check_ops = {
.size = sizeof(struct page_table_check),
.need = need_page_table_check,
.init = init_page_table_check,
.need_shared_flags = false,
};
static struct page_table_check *get_page_table_check(struct page_ext *page_ext)
{
BUG_ON(!page_ext);
return page_ext_data(page_ext, &page_table_check_ops);
}
/*
* An entry is removed from the page table, decrement the counters for that page
* verify that it is of correct type and counters do not become negative.
*/
static void page_table_check_clear(unsigned long pfn, unsigned long pgcnt)
{
struct page_ext *page_ext;
struct page *page;
unsigned long i;
bool anon;
if (!pfn_valid(pfn))
return;
page = pfn_to_page(pfn);
page_ext = page_ext_get(page);
BUG_ON(PageSlab(page));
anon = PageAnon(page);
for (i = 0; i < pgcnt; i++) {
struct page_table_check *ptc = get_page_table_check(page_ext);
if (anon) {
BUG_ON(atomic_read(&ptc->file_map_count));
BUG_ON(atomic_dec_return(&ptc->anon_map_count) < 0);
} else {
BUG_ON(atomic_read(&ptc->anon_map_count));
BUG_ON(atomic_dec_return(&ptc->file_map_count) < 0);
}
page_ext = page_ext_next(page_ext);
}
page_ext_put(page_ext);
}
/*
* A new entry is added to the page table, increment the counters for that page
* verify that it is of correct type and is not being mapped with a different
* type to a different process.
*/
static void page_table_check_set(unsigned long pfn, unsigned long pgcnt,
bool rw)
{
struct page_ext *page_ext;
struct page *page;
unsigned long i;
bool anon;
if (!pfn_valid(pfn))
return;
page = pfn_to_page(pfn);
page_ext = page_ext_get(page);
BUG_ON(PageSlab(page));
anon = PageAnon(page);
for (i = 0; i < pgcnt; i++) {
struct page_table_check *ptc = get_page_table_check(page_ext);
if (anon) {
BUG_ON(atomic_read(&ptc->file_map_count));
BUG_ON(atomic_inc_return(&ptc->anon_map_count) > 1 && rw);
} else {
BUG_ON(atomic_read(&ptc->anon_map_count));
BUG_ON(atomic_inc_return(&ptc->file_map_count) < 0);
}
page_ext = page_ext_next(page_ext);
}
page_ext_put(page_ext);
}
/*
* page is on free list, or is being allocated, verify that counters are zeroes
* crash if they are not.
*/
void __page_table_check_zero(struct page *page, unsigned int order)
{
struct page_ext *page_ext;
unsigned long i;
BUG_ON(PageSlab(page));
page_ext = page_ext_get(page);
BUG_ON(!page_ext);
for (i = 0; i < (1ul << order); i++) {
struct page_table_check *ptc = get_page_table_check(page_ext);
BUG_ON(atomic_read(&ptc->anon_map_count));
BUG_ON(atomic_read(&ptc->file_map_count));
page_ext = page_ext_next(page_ext);
}
page_ext_put(page_ext);
}
void __page_table_check_pte_clear(struct mm_struct *mm, pte_t pte)
{
if (&init_mm == mm)
return;
if (pte_user_accessible_page(pte)) {
page_table_check_clear(pte_pfn(pte), PAGE_SIZE >> PAGE_SHIFT);
}
}
EXPORT_SYMBOL(__page_table_check_pte_clear);
void __page_table_check_pmd_clear(struct mm_struct *mm, pmd_t pmd)
{
if (&init_mm == mm)
return;
if (pmd_user_accessible_page(pmd)) {
page_table_check_clear(pmd_pfn(pmd), PMD_SIZE >> PAGE_SHIFT);
}
}
EXPORT_SYMBOL(__page_table_check_pmd_clear);
void __page_table_check_pud_clear(struct mm_struct *mm, pud_t pud)
{
if (&init_mm == mm)
return;
if (pud_user_accessible_page(pud)) {
page_table_check_clear(pud_pfn(pud), PUD_SIZE >> PAGE_SHIFT);
}
}
EXPORT_SYMBOL(__page_table_check_pud_clear);
void __page_table_check_ptes_set(struct mm_struct *mm, pte_t *ptep, pte_t pte,
unsigned int nr)
{
unsigned int i;
if (&init_mm == mm)
return;
for (i = 0; i < nr; i++)
__page_table_check_pte_clear(mm, ptep_get(ptep + i));
if (pte_user_accessible_page(pte))
page_table_check_set(pte_pfn(pte), nr, pte_write(pte));
}
EXPORT_SYMBOL(__page_table_check_ptes_set);
void __page_table_check_pmd_set(struct mm_struct *mm, pmd_t *pmdp, pmd_t pmd)
{
if (&init_mm == mm)
return;
__page_table_check_pmd_clear(mm, *pmdp);
if (pmd_user_accessible_page(pmd)) {
page_table_check_set(pmd_pfn(pmd), PMD_SIZE >> PAGE_SHIFT,
pmd_write(pmd));
}
}
EXPORT_SYMBOL(__page_table_check_pmd_set);
void __page_table_check_pud_set(struct mm_struct *mm, pud_t *pudp, pud_t pud)
{
if (&init_mm == mm)
return;
__page_table_check_pud_clear(mm, *pudp);
if (pud_user_accessible_page(pud)) {
page_table_check_set(pud_pfn(pud), PUD_SIZE >> PAGE_SHIFT,
pud_write(pud));
}
}
EXPORT_SYMBOL(__page_table_check_pud_set);
void __page_table_check_pte_clear_range(struct mm_struct *mm,
unsigned long addr,
pmd_t pmd)
{
if (&init_mm == mm)
return;
if (!pmd_bad(pmd) && !pmd_leaf(pmd)) {
pte_t *ptep = pte_offset_map(&pmd, addr);
unsigned long i;
if (WARN_ON(!ptep))
return;
for (i = 0; i < PTRS_PER_PTE; i++) {
__page_table_check_pte_clear(mm, ptep_get(ptep));
addr += PAGE_SIZE;
ptep++;
}
pte_unmap(ptep - PTRS_PER_PTE);
}
}
| linux-master | mm/page_table_check.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/mm/vmstat.c
*
* Manages VM statistics
* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
*
* zoned VM statistics
* Copyright (C) 2006 Silicon Graphics, Inc.,
* Christoph Lameter <[email protected]>
* Copyright (C) 2008-2014 Christoph Lameter
*/
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/cpu.h>
#include <linux/cpumask.h>
#include <linux/vmstat.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/debugfs.h>
#include <linux/sched.h>
#include <linux/math64.h>
#include <linux/writeback.h>
#include <linux/compaction.h>
#include <linux/mm_inline.h>
#include <linux/page_owner.h>
#include <linux/sched/isolation.h>
#include "internal.h"
#ifdef CONFIG_NUMA
int sysctl_vm_numa_stat = ENABLE_NUMA_STAT;
/* zero numa counters within a zone */
static void zero_zone_numa_counters(struct zone *zone)
{
int item, cpu;
for (item = 0; item < NR_VM_NUMA_EVENT_ITEMS; item++) {
atomic_long_set(&zone->vm_numa_event[item], 0);
for_each_online_cpu(cpu) {
per_cpu_ptr(zone->per_cpu_zonestats, cpu)->vm_numa_event[item]
= 0;
}
}
}
/* zero numa counters of all the populated zones */
static void zero_zones_numa_counters(void)
{
struct zone *zone;
for_each_populated_zone(zone)
zero_zone_numa_counters(zone);
}
/* zero global numa counters */
static void zero_global_numa_counters(void)
{
int item;
for (item = 0; item < NR_VM_NUMA_EVENT_ITEMS; item++)
atomic_long_set(&vm_numa_event[item], 0);
}
static void invalid_numa_statistics(void)
{
zero_zones_numa_counters();
zero_global_numa_counters();
}
static DEFINE_MUTEX(vm_numa_stat_lock);
int sysctl_vm_numa_stat_handler(struct ctl_table *table, int write,
void *buffer, size_t *length, loff_t *ppos)
{
int ret, oldval;
mutex_lock(&vm_numa_stat_lock);
if (write)
oldval = sysctl_vm_numa_stat;
ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
if (ret || !write)
goto out;
if (oldval == sysctl_vm_numa_stat)
goto out;
else if (sysctl_vm_numa_stat == ENABLE_NUMA_STAT) {
static_branch_enable(&vm_numa_stat_key);
pr_info("enable numa statistics\n");
} else {
static_branch_disable(&vm_numa_stat_key);
invalid_numa_statistics();
pr_info("disable numa statistics, and clear numa counters\n");
}
out:
mutex_unlock(&vm_numa_stat_lock);
return ret;
}
#endif
#ifdef CONFIG_VM_EVENT_COUNTERS
DEFINE_PER_CPU(struct vm_event_state, vm_event_states) = {{0}};
EXPORT_PER_CPU_SYMBOL(vm_event_states);
static void sum_vm_events(unsigned long *ret)
{
int cpu;
int i;
memset(ret, 0, NR_VM_EVENT_ITEMS * sizeof(unsigned long));
for_each_online_cpu(cpu) {
struct vm_event_state *this = &per_cpu(vm_event_states, cpu);
for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
ret[i] += this->event[i];
}
}
/*
* Accumulate the vm event counters across all CPUs.
* The result is unavoidably approximate - it can change
* during and after execution of this function.
*/
void all_vm_events(unsigned long *ret)
{
cpus_read_lock();
sum_vm_events(ret);
cpus_read_unlock();
}
EXPORT_SYMBOL_GPL(all_vm_events);
/*
* Fold the foreign cpu events into our own.
*
* This is adding to the events on one processor
* but keeps the global counts constant.
*/
void vm_events_fold_cpu(int cpu)
{
struct vm_event_state *fold_state = &per_cpu(vm_event_states, cpu);
int i;
for (i = 0; i < NR_VM_EVENT_ITEMS; i++) {
count_vm_events(i, fold_state->event[i]);
fold_state->event[i] = 0;
}
}
#endif /* CONFIG_VM_EVENT_COUNTERS */
/*
* Manage combined zone based / global counters
*
* vm_stat contains the global counters
*/
atomic_long_t vm_zone_stat[NR_VM_ZONE_STAT_ITEMS] __cacheline_aligned_in_smp;
atomic_long_t vm_node_stat[NR_VM_NODE_STAT_ITEMS] __cacheline_aligned_in_smp;
atomic_long_t vm_numa_event[NR_VM_NUMA_EVENT_ITEMS] __cacheline_aligned_in_smp;
EXPORT_SYMBOL(vm_zone_stat);
EXPORT_SYMBOL(vm_node_stat);
#ifdef CONFIG_NUMA
static void fold_vm_zone_numa_events(struct zone *zone)
{
unsigned long zone_numa_events[NR_VM_NUMA_EVENT_ITEMS] = { 0, };
int cpu;
enum numa_stat_item item;
for_each_online_cpu(cpu) {
struct per_cpu_zonestat *pzstats;
pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu);
for (item = 0; item < NR_VM_NUMA_EVENT_ITEMS; item++)
zone_numa_events[item] += xchg(&pzstats->vm_numa_event[item], 0);
}
for (item = 0; item < NR_VM_NUMA_EVENT_ITEMS; item++)
zone_numa_event_add(zone_numa_events[item], zone, item);
}
void fold_vm_numa_events(void)
{
struct zone *zone;
for_each_populated_zone(zone)
fold_vm_zone_numa_events(zone);
}
#endif
#ifdef CONFIG_SMP
int calculate_pressure_threshold(struct zone *zone)
{
int threshold;
int watermark_distance;
/*
* As vmstats are not up to date, there is drift between the estimated
* and real values. For high thresholds and a high number of CPUs, it
* is possible for the min watermark to be breached while the estimated
* value looks fine. The pressure threshold is a reduced value such
* that even the maximum amount of drift will not accidentally breach
* the min watermark
*/
watermark_distance = low_wmark_pages(zone) - min_wmark_pages(zone);
threshold = max(1, (int)(watermark_distance / num_online_cpus()));
/*
* Maximum threshold is 125
*/
threshold = min(125, threshold);
return threshold;
}
int calculate_normal_threshold(struct zone *zone)
{
int threshold;
int mem; /* memory in 128 MB units */
/*
* The threshold scales with the number of processors and the amount
* of memory per zone. More memory means that we can defer updates for
* longer, more processors could lead to more contention.
* fls() is used to have a cheap way of logarithmic scaling.
*
* Some sample thresholds:
*
* Threshold Processors (fls) Zonesize fls(mem)+1
* ------------------------------------------------------------------
* 8 1 1 0.9-1 GB 4
* 16 2 2 0.9-1 GB 4
* 20 2 2 1-2 GB 5
* 24 2 2 2-4 GB 6
* 28 2 2 4-8 GB 7
* 32 2 2 8-16 GB 8
* 4 2 2 <128M 1
* 30 4 3 2-4 GB 5
* 48 4 3 8-16 GB 8
* 32 8 4 1-2 GB 4
* 32 8 4 0.9-1GB 4
* 10 16 5 <128M 1
* 40 16 5 900M 4
* 70 64 7 2-4 GB 5
* 84 64 7 4-8 GB 6
* 108 512 9 4-8 GB 6
* 125 1024 10 8-16 GB 8
* 125 1024 10 16-32 GB 9
*/
mem = zone_managed_pages(zone) >> (27 - PAGE_SHIFT);
threshold = 2 * fls(num_online_cpus()) * (1 + fls(mem));
/*
* Maximum threshold is 125
*/
threshold = min(125, threshold);
return threshold;
}
/*
* Refresh the thresholds for each zone.
*/
void refresh_zone_stat_thresholds(void)
{
struct pglist_data *pgdat;
struct zone *zone;
int cpu;
int threshold;
/* Zero current pgdat thresholds */
for_each_online_pgdat(pgdat) {
for_each_online_cpu(cpu) {
per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold = 0;
}
}
for_each_populated_zone(zone) {
struct pglist_data *pgdat = zone->zone_pgdat;
unsigned long max_drift, tolerate_drift;
threshold = calculate_normal_threshold(zone);
for_each_online_cpu(cpu) {
int pgdat_threshold;
per_cpu_ptr(zone->per_cpu_zonestats, cpu)->stat_threshold
= threshold;
/* Base nodestat threshold on the largest populated zone. */
pgdat_threshold = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold;
per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold
= max(threshold, pgdat_threshold);
}
/*
* Only set percpu_drift_mark if there is a danger that
* NR_FREE_PAGES reports the low watermark is ok when in fact
* the min watermark could be breached by an allocation
*/
tolerate_drift = low_wmark_pages(zone) - min_wmark_pages(zone);
max_drift = num_online_cpus() * threshold;
if (max_drift > tolerate_drift)
zone->percpu_drift_mark = high_wmark_pages(zone) +
max_drift;
}
}
void set_pgdat_percpu_threshold(pg_data_t *pgdat,
int (*calculate_pressure)(struct zone *))
{
struct zone *zone;
int cpu;
int threshold;
int i;
for (i = 0; i < pgdat->nr_zones; i++) {
zone = &pgdat->node_zones[i];
if (!zone->percpu_drift_mark)
continue;
threshold = (*calculate_pressure)(zone);
for_each_online_cpu(cpu)
per_cpu_ptr(zone->per_cpu_zonestats, cpu)->stat_threshold
= threshold;
}
}
/*
* For use when we know that interrupts are disabled,
* or when we know that preemption is disabled and that
* particular counter cannot be updated from interrupt context.
*/
void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
long delta)
{
struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
s8 __percpu *p = pcp->vm_stat_diff + item;
long x;
long t;
/*
* Accurate vmstat updates require a RMW. On !PREEMPT_RT kernels,
* atomicity is provided by IRQs being disabled -- either explicitly
* or via local_lock_irq. On PREEMPT_RT, local_lock_irq only disables
* CPU migrations and preemption potentially corrupts a counter so
* disable preemption.
*/
preempt_disable_nested();
x = delta + __this_cpu_read(*p);
t = __this_cpu_read(pcp->stat_threshold);
if (unlikely(abs(x) > t)) {
zone_page_state_add(x, zone, item);
x = 0;
}
__this_cpu_write(*p, x);
preempt_enable_nested();
}
EXPORT_SYMBOL(__mod_zone_page_state);
void __mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
long delta)
{
struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
s8 __percpu *p = pcp->vm_node_stat_diff + item;
long x;
long t;
if (vmstat_item_in_bytes(item)) {
/*
* Only cgroups use subpage accounting right now; at
* the global level, these items still change in
* multiples of whole pages. Store them as pages
* internally to keep the per-cpu counters compact.
*/
VM_WARN_ON_ONCE(delta & (PAGE_SIZE - 1));
delta >>= PAGE_SHIFT;
}
/* See __mod_node_page_state */
preempt_disable_nested();
x = delta + __this_cpu_read(*p);
t = __this_cpu_read(pcp->stat_threshold);
if (unlikely(abs(x) > t)) {
node_page_state_add(x, pgdat, item);
x = 0;
}
__this_cpu_write(*p, x);
preempt_enable_nested();
}
EXPORT_SYMBOL(__mod_node_page_state);
/*
* Optimized increment and decrement functions.
*
* These are only for a single page and therefore can take a struct page *
* argument instead of struct zone *. This allows the inclusion of the code
* generated for page_zone(page) into the optimized functions.
*
* No overflow check is necessary and therefore the differential can be
* incremented or decremented in place which may allow the compilers to
* generate better code.
* The increment or decrement is known and therefore one boundary check can
* be omitted.
*
* NOTE: These functions are very performance sensitive. Change only
* with care.
*
* Some processors have inc/dec instructions that are atomic vs an interrupt.
* However, the code must first determine the differential location in a zone
* based on the processor number and then inc/dec the counter. There is no
* guarantee without disabling preemption that the processor will not change
* in between and therefore the atomicity vs. interrupt cannot be exploited
* in a useful way here.
*/
void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
{
struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
s8 __percpu *p = pcp->vm_stat_diff + item;
s8 v, t;
/* See __mod_node_page_state */
preempt_disable_nested();
v = __this_cpu_inc_return(*p);
t = __this_cpu_read(pcp->stat_threshold);
if (unlikely(v > t)) {
s8 overstep = t >> 1;
zone_page_state_add(v + overstep, zone, item);
__this_cpu_write(*p, -overstep);
}
preempt_enable_nested();
}
void __inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
{
struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
s8 __percpu *p = pcp->vm_node_stat_diff + item;
s8 v, t;
VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
/* See __mod_node_page_state */
preempt_disable_nested();
v = __this_cpu_inc_return(*p);
t = __this_cpu_read(pcp->stat_threshold);
if (unlikely(v > t)) {
s8 overstep = t >> 1;
node_page_state_add(v + overstep, pgdat, item);
__this_cpu_write(*p, -overstep);
}
preempt_enable_nested();
}
void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
{
__inc_zone_state(page_zone(page), item);
}
EXPORT_SYMBOL(__inc_zone_page_state);
void __inc_node_page_state(struct page *page, enum node_stat_item item)
{
__inc_node_state(page_pgdat(page), item);
}
EXPORT_SYMBOL(__inc_node_page_state);
void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
{
struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
s8 __percpu *p = pcp->vm_stat_diff + item;
s8 v, t;
/* See __mod_node_page_state */
preempt_disable_nested();
v = __this_cpu_dec_return(*p);
t = __this_cpu_read(pcp->stat_threshold);
if (unlikely(v < - t)) {
s8 overstep = t >> 1;
zone_page_state_add(v - overstep, zone, item);
__this_cpu_write(*p, overstep);
}
preempt_enable_nested();
}
void __dec_node_state(struct pglist_data *pgdat, enum node_stat_item item)
{
struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
s8 __percpu *p = pcp->vm_node_stat_diff + item;
s8 v, t;
VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
/* See __mod_node_page_state */
preempt_disable_nested();
v = __this_cpu_dec_return(*p);
t = __this_cpu_read(pcp->stat_threshold);
if (unlikely(v < - t)) {
s8 overstep = t >> 1;
node_page_state_add(v - overstep, pgdat, item);
__this_cpu_write(*p, overstep);
}
preempt_enable_nested();
}
void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
{
__dec_zone_state(page_zone(page), item);
}
EXPORT_SYMBOL(__dec_zone_page_state);
void __dec_node_page_state(struct page *page, enum node_stat_item item)
{
__dec_node_state(page_pgdat(page), item);
}
EXPORT_SYMBOL(__dec_node_page_state);
#ifdef CONFIG_HAVE_CMPXCHG_LOCAL
/*
* If we have cmpxchg_local support then we do not need to incur the overhead
* that comes with local_irq_save/restore if we use this_cpu_cmpxchg.
*
* mod_state() modifies the zone counter state through atomic per cpu
* operations.
*
* Overstep mode specifies how overstep should handled:
* 0 No overstepping
* 1 Overstepping half of threshold
* -1 Overstepping minus half of threshold
*/
static inline void mod_zone_state(struct zone *zone,
enum zone_stat_item item, long delta, int overstep_mode)
{
struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
s8 __percpu *p = pcp->vm_stat_diff + item;
long o, n, t, z;
do {
z = 0; /* overflow to zone counters */
/*
* The fetching of the stat_threshold is racy. We may apply
* a counter threshold to the wrong the cpu if we get
* rescheduled while executing here. However, the next
* counter update will apply the threshold again and
* therefore bring the counter under the threshold again.
*
* Most of the time the thresholds are the same anyways
* for all cpus in a zone.
*/
t = this_cpu_read(pcp->stat_threshold);
o = this_cpu_read(*p);
n = delta + o;
if (abs(n) > t) {
int os = overstep_mode * (t >> 1) ;
/* Overflow must be added to zone counters */
z = n + os;
n = -os;
}
} while (this_cpu_cmpxchg(*p, o, n) != o);
if (z)
zone_page_state_add(z, zone, item);
}
void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
long delta)
{
mod_zone_state(zone, item, delta, 0);
}
EXPORT_SYMBOL(mod_zone_page_state);
void inc_zone_page_state(struct page *page, enum zone_stat_item item)
{
mod_zone_state(page_zone(page), item, 1, 1);
}
EXPORT_SYMBOL(inc_zone_page_state);
void dec_zone_page_state(struct page *page, enum zone_stat_item item)
{
mod_zone_state(page_zone(page), item, -1, -1);
}
EXPORT_SYMBOL(dec_zone_page_state);
static inline void mod_node_state(struct pglist_data *pgdat,
enum node_stat_item item, int delta, int overstep_mode)
{
struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
s8 __percpu *p = pcp->vm_node_stat_diff + item;
long o, n, t, z;
if (vmstat_item_in_bytes(item)) {
/*
* Only cgroups use subpage accounting right now; at
* the global level, these items still change in
* multiples of whole pages. Store them as pages
* internally to keep the per-cpu counters compact.
*/
VM_WARN_ON_ONCE(delta & (PAGE_SIZE - 1));
delta >>= PAGE_SHIFT;
}
do {
z = 0; /* overflow to node counters */
/*
* The fetching of the stat_threshold is racy. We may apply
* a counter threshold to the wrong the cpu if we get
* rescheduled while executing here. However, the next
* counter update will apply the threshold again and
* therefore bring the counter under the threshold again.
*
* Most of the time the thresholds are the same anyways
* for all cpus in a node.
*/
t = this_cpu_read(pcp->stat_threshold);
o = this_cpu_read(*p);
n = delta + o;
if (abs(n) > t) {
int os = overstep_mode * (t >> 1) ;
/* Overflow must be added to node counters */
z = n + os;
n = -os;
}
} while (this_cpu_cmpxchg(*p, o, n) != o);
if (z)
node_page_state_add(z, pgdat, item);
}
void mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
long delta)
{
mod_node_state(pgdat, item, delta, 0);
}
EXPORT_SYMBOL(mod_node_page_state);
void inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
{
mod_node_state(pgdat, item, 1, 1);
}
void inc_node_page_state(struct page *page, enum node_stat_item item)
{
mod_node_state(page_pgdat(page), item, 1, 1);
}
EXPORT_SYMBOL(inc_node_page_state);
void dec_node_page_state(struct page *page, enum node_stat_item item)
{
mod_node_state(page_pgdat(page), item, -1, -1);
}
EXPORT_SYMBOL(dec_node_page_state);
#else
/*
* Use interrupt disable to serialize counter updates
*/
void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
long delta)
{
unsigned long flags;
local_irq_save(flags);
__mod_zone_page_state(zone, item, delta);
local_irq_restore(flags);
}
EXPORT_SYMBOL(mod_zone_page_state);
void inc_zone_page_state(struct page *page, enum zone_stat_item item)
{
unsigned long flags;
struct zone *zone;
zone = page_zone(page);
local_irq_save(flags);
__inc_zone_state(zone, item);
local_irq_restore(flags);
}
EXPORT_SYMBOL(inc_zone_page_state);
void dec_zone_page_state(struct page *page, enum zone_stat_item item)
{
unsigned long flags;
local_irq_save(flags);
__dec_zone_page_state(page, item);
local_irq_restore(flags);
}
EXPORT_SYMBOL(dec_zone_page_state);
void inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
{
unsigned long flags;
local_irq_save(flags);
__inc_node_state(pgdat, item);
local_irq_restore(flags);
}
EXPORT_SYMBOL(inc_node_state);
void mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
long delta)
{
unsigned long flags;
local_irq_save(flags);
__mod_node_page_state(pgdat, item, delta);
local_irq_restore(flags);
}
EXPORT_SYMBOL(mod_node_page_state);
void inc_node_page_state(struct page *page, enum node_stat_item item)
{
unsigned long flags;
struct pglist_data *pgdat;
pgdat = page_pgdat(page);
local_irq_save(flags);
__inc_node_state(pgdat, item);
local_irq_restore(flags);
}
EXPORT_SYMBOL(inc_node_page_state);
void dec_node_page_state(struct page *page, enum node_stat_item item)
{
unsigned long flags;
local_irq_save(flags);
__dec_node_page_state(page, item);
local_irq_restore(flags);
}
EXPORT_SYMBOL(dec_node_page_state);
#endif
/*
* Fold a differential into the global counters.
* Returns the number of counters updated.
*/
static int fold_diff(int *zone_diff, int *node_diff)
{
int i;
int changes = 0;
for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
if (zone_diff[i]) {
atomic_long_add(zone_diff[i], &vm_zone_stat[i]);
changes++;
}
for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
if (node_diff[i]) {
atomic_long_add(node_diff[i], &vm_node_stat[i]);
changes++;
}
return changes;
}
/*
* Update the zone counters for the current cpu.
*
* Note that refresh_cpu_vm_stats strives to only access
* node local memory. The per cpu pagesets on remote zones are placed
* in the memory local to the processor using that pageset. So the
* loop over all zones will access a series of cachelines local to
* the processor.
*
* The call to zone_page_state_add updates the cachelines with the
* statistics in the remote zone struct as well as the global cachelines
* with the global counters. These could cause remote node cache line
* bouncing and will have to be only done when necessary.
*
* The function returns the number of global counters updated.
*/
static int refresh_cpu_vm_stats(bool do_pagesets)
{
struct pglist_data *pgdat;
struct zone *zone;
int i;
int global_zone_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
int global_node_diff[NR_VM_NODE_STAT_ITEMS] = { 0, };
int changes = 0;
for_each_populated_zone(zone) {
struct per_cpu_zonestat __percpu *pzstats = zone->per_cpu_zonestats;
#ifdef CONFIG_NUMA
struct per_cpu_pages __percpu *pcp = zone->per_cpu_pageset;
#endif
for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
int v;
v = this_cpu_xchg(pzstats->vm_stat_diff[i], 0);
if (v) {
atomic_long_add(v, &zone->vm_stat[i]);
global_zone_diff[i] += v;
#ifdef CONFIG_NUMA
/* 3 seconds idle till flush */
__this_cpu_write(pcp->expire, 3);
#endif
}
}
#ifdef CONFIG_NUMA
if (do_pagesets) {
cond_resched();
/*
* Deal with draining the remote pageset of this
* processor
*
* Check if there are pages remaining in this pageset
* if not then there is nothing to expire.
*/
if (!__this_cpu_read(pcp->expire) ||
!__this_cpu_read(pcp->count))
continue;
/*
* We never drain zones local to this processor.
*/
if (zone_to_nid(zone) == numa_node_id()) {
__this_cpu_write(pcp->expire, 0);
continue;
}
if (__this_cpu_dec_return(pcp->expire))
continue;
if (__this_cpu_read(pcp->count)) {
drain_zone_pages(zone, this_cpu_ptr(pcp));
changes++;
}
}
#endif
}
for_each_online_pgdat(pgdat) {
struct per_cpu_nodestat __percpu *p = pgdat->per_cpu_nodestats;
for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
int v;
v = this_cpu_xchg(p->vm_node_stat_diff[i], 0);
if (v) {
atomic_long_add(v, &pgdat->vm_stat[i]);
global_node_diff[i] += v;
}
}
}
changes += fold_diff(global_zone_diff, global_node_diff);
return changes;
}
/*
* Fold the data for an offline cpu into the global array.
* There cannot be any access by the offline cpu and therefore
* synchronization is simplified.
*/
void cpu_vm_stats_fold(int cpu)
{
struct pglist_data *pgdat;
struct zone *zone;
int i;
int global_zone_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
int global_node_diff[NR_VM_NODE_STAT_ITEMS] = { 0, };
for_each_populated_zone(zone) {
struct per_cpu_zonestat *pzstats;
pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu);
for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
if (pzstats->vm_stat_diff[i]) {
int v;
v = pzstats->vm_stat_diff[i];
pzstats->vm_stat_diff[i] = 0;
atomic_long_add(v, &zone->vm_stat[i]);
global_zone_diff[i] += v;
}
}
#ifdef CONFIG_NUMA
for (i = 0; i < NR_VM_NUMA_EVENT_ITEMS; i++) {
if (pzstats->vm_numa_event[i]) {
unsigned long v;
v = pzstats->vm_numa_event[i];
pzstats->vm_numa_event[i] = 0;
zone_numa_event_add(v, zone, i);
}
}
#endif
}
for_each_online_pgdat(pgdat) {
struct per_cpu_nodestat *p;
p = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu);
for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
if (p->vm_node_stat_diff[i]) {
int v;
v = p->vm_node_stat_diff[i];
p->vm_node_stat_diff[i] = 0;
atomic_long_add(v, &pgdat->vm_stat[i]);
global_node_diff[i] += v;
}
}
fold_diff(global_zone_diff, global_node_diff);
}
/*
* this is only called if !populated_zone(zone), which implies no other users of
* pset->vm_stat_diff[] exist.
*/
void drain_zonestat(struct zone *zone, struct per_cpu_zonestat *pzstats)
{
unsigned long v;
int i;
for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
if (pzstats->vm_stat_diff[i]) {
v = pzstats->vm_stat_diff[i];
pzstats->vm_stat_diff[i] = 0;
zone_page_state_add(v, zone, i);
}
}
#ifdef CONFIG_NUMA
for (i = 0; i < NR_VM_NUMA_EVENT_ITEMS; i++) {
if (pzstats->vm_numa_event[i]) {
v = pzstats->vm_numa_event[i];
pzstats->vm_numa_event[i] = 0;
zone_numa_event_add(v, zone, i);
}
}
#endif
}
#endif
#ifdef CONFIG_NUMA
/*
* Determine the per node value of a stat item. This function
* is called frequently in a NUMA machine, so try to be as
* frugal as possible.
*/
unsigned long sum_zone_node_page_state(int node,
enum zone_stat_item item)
{
struct zone *zones = NODE_DATA(node)->node_zones;
int i;
unsigned long count = 0;
for (i = 0; i < MAX_NR_ZONES; i++)
count += zone_page_state(zones + i, item);
return count;
}
/* Determine the per node value of a numa stat item. */
unsigned long sum_zone_numa_event_state(int node,
enum numa_stat_item item)
{
struct zone *zones = NODE_DATA(node)->node_zones;
unsigned long count = 0;
int i;
for (i = 0; i < MAX_NR_ZONES; i++)
count += zone_numa_event_state(zones + i, item);
return count;
}
/*
* Determine the per node value of a stat item.
*/
unsigned long node_page_state_pages(struct pglist_data *pgdat,
enum node_stat_item item)
{
long x = atomic_long_read(&pgdat->vm_stat[item]);
#ifdef CONFIG_SMP
if (x < 0)
x = 0;
#endif
return x;
}
unsigned long node_page_state(struct pglist_data *pgdat,
enum node_stat_item item)
{
VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
return node_page_state_pages(pgdat, item);
}
#endif
#ifdef CONFIG_COMPACTION
struct contig_page_info {
unsigned long free_pages;
unsigned long free_blocks_total;
unsigned long free_blocks_suitable;
};
/*
* Calculate the number of free pages in a zone, how many contiguous
* pages are free and how many are large enough to satisfy an allocation of
* the target size. Note that this function makes no attempt to estimate
* how many suitable free blocks there *might* be if MOVABLE pages were
* migrated. Calculating that is possible, but expensive and can be
* figured out from userspace
*/
static void fill_contig_page_info(struct zone *zone,
unsigned int suitable_order,
struct contig_page_info *info)
{
unsigned int order;
info->free_pages = 0;
info->free_blocks_total = 0;
info->free_blocks_suitable = 0;
for (order = 0; order <= MAX_ORDER; order++) {
unsigned long blocks;
/*
* Count number of free blocks.
*
* Access to nr_free is lockless as nr_free is used only for
* diagnostic purposes. Use data_race to avoid KCSAN warning.
*/
blocks = data_race(zone->free_area[order].nr_free);
info->free_blocks_total += blocks;
/* Count free base pages */
info->free_pages += blocks << order;
/* Count the suitable free blocks */
if (order >= suitable_order)
info->free_blocks_suitable += blocks <<
(order - suitable_order);
}
}
/*
* A fragmentation index only makes sense if an allocation of a requested
* size would fail. If that is true, the fragmentation index indicates
* whether external fragmentation or a lack of memory was the problem.
* The value can be used to determine if page reclaim or compaction
* should be used
*/
static int __fragmentation_index(unsigned int order, struct contig_page_info *info)
{
unsigned long requested = 1UL << order;
if (WARN_ON_ONCE(order > MAX_ORDER))
return 0;
if (!info->free_blocks_total)
return 0;
/* Fragmentation index only makes sense when a request would fail */
if (info->free_blocks_suitable)
return -1000;
/*
* Index is between 0 and 1 so return within 3 decimal places
*
* 0 => allocation would fail due to lack of memory
* 1 => allocation would fail due to fragmentation
*/
return 1000 - div_u64( (1000+(div_u64(info->free_pages * 1000ULL, requested))), info->free_blocks_total);
}
/*
* Calculates external fragmentation within a zone wrt the given order.
* It is defined as the percentage of pages found in blocks of size
* less than 1 << order. It returns values in range [0, 100].
*/
unsigned int extfrag_for_order(struct zone *zone, unsigned int order)
{
struct contig_page_info info;
fill_contig_page_info(zone, order, &info);
if (info.free_pages == 0)
return 0;
return div_u64((info.free_pages -
(info.free_blocks_suitable << order)) * 100,
info.free_pages);
}
/* Same as __fragmentation index but allocs contig_page_info on stack */
int fragmentation_index(struct zone *zone, unsigned int order)
{
struct contig_page_info info;
fill_contig_page_info(zone, order, &info);
return __fragmentation_index(order, &info);
}
#endif
#if defined(CONFIG_PROC_FS) || defined(CONFIG_SYSFS) || \
defined(CONFIG_NUMA) || defined(CONFIG_MEMCG)
#ifdef CONFIG_ZONE_DMA
#define TEXT_FOR_DMA(xx) xx "_dma",
#else
#define TEXT_FOR_DMA(xx)
#endif
#ifdef CONFIG_ZONE_DMA32
#define TEXT_FOR_DMA32(xx) xx "_dma32",
#else
#define TEXT_FOR_DMA32(xx)
#endif
#ifdef CONFIG_HIGHMEM
#define TEXT_FOR_HIGHMEM(xx) xx "_high",
#else
#define TEXT_FOR_HIGHMEM(xx)
#endif
#ifdef CONFIG_ZONE_DEVICE
#define TEXT_FOR_DEVICE(xx) xx "_device",
#else
#define TEXT_FOR_DEVICE(xx)
#endif
#define TEXTS_FOR_ZONES(xx) TEXT_FOR_DMA(xx) TEXT_FOR_DMA32(xx) xx "_normal", \
TEXT_FOR_HIGHMEM(xx) xx "_movable", \
TEXT_FOR_DEVICE(xx)
const char * const vmstat_text[] = {
/* enum zone_stat_item counters */
"nr_free_pages",
"nr_zone_inactive_anon",
"nr_zone_active_anon",
"nr_zone_inactive_file",
"nr_zone_active_file",
"nr_zone_unevictable",
"nr_zone_write_pending",
"nr_mlock",
"nr_bounce",
#if IS_ENABLED(CONFIG_ZSMALLOC)
"nr_zspages",
#endif
"nr_free_cma",
#ifdef CONFIG_UNACCEPTED_MEMORY
"nr_unaccepted",
#endif
/* enum numa_stat_item counters */
#ifdef CONFIG_NUMA
"numa_hit",
"numa_miss",
"numa_foreign",
"numa_interleave",
"numa_local",
"numa_other",
#endif
/* enum node_stat_item counters */
"nr_inactive_anon",
"nr_active_anon",
"nr_inactive_file",
"nr_active_file",
"nr_unevictable",
"nr_slab_reclaimable",
"nr_slab_unreclaimable",
"nr_isolated_anon",
"nr_isolated_file",
"workingset_nodes",
"workingset_refault_anon",
"workingset_refault_file",
"workingset_activate_anon",
"workingset_activate_file",
"workingset_restore_anon",
"workingset_restore_file",
"workingset_nodereclaim",
"nr_anon_pages",
"nr_mapped",
"nr_file_pages",
"nr_dirty",
"nr_writeback",
"nr_writeback_temp",
"nr_shmem",
"nr_shmem_hugepages",
"nr_shmem_pmdmapped",
"nr_file_hugepages",
"nr_file_pmdmapped",
"nr_anon_transparent_hugepages",
"nr_vmscan_write",
"nr_vmscan_immediate_reclaim",
"nr_dirtied",
"nr_written",
"nr_throttled_written",
"nr_kernel_misc_reclaimable",
"nr_foll_pin_acquired",
"nr_foll_pin_released",
"nr_kernel_stack",
#if IS_ENABLED(CONFIG_SHADOW_CALL_STACK)
"nr_shadow_call_stack",
#endif
"nr_page_table_pages",
"nr_sec_page_table_pages",
#ifdef CONFIG_SWAP
"nr_swapcached",
#endif
#ifdef CONFIG_NUMA_BALANCING
"pgpromote_success",
"pgpromote_candidate",
#endif
/* enum writeback_stat_item counters */
"nr_dirty_threshold",
"nr_dirty_background_threshold",
#if defined(CONFIG_VM_EVENT_COUNTERS) || defined(CONFIG_MEMCG)
/* enum vm_event_item counters */
"pgpgin",
"pgpgout",
"pswpin",
"pswpout",
TEXTS_FOR_ZONES("pgalloc")
TEXTS_FOR_ZONES("allocstall")
TEXTS_FOR_ZONES("pgskip")
"pgfree",
"pgactivate",
"pgdeactivate",
"pglazyfree",
"pgfault",
"pgmajfault",
"pglazyfreed",
"pgrefill",
"pgreuse",
"pgsteal_kswapd",
"pgsteal_direct",
"pgsteal_khugepaged",
"pgdemote_kswapd",
"pgdemote_direct",
"pgdemote_khugepaged",
"pgscan_kswapd",
"pgscan_direct",
"pgscan_khugepaged",
"pgscan_direct_throttle",
"pgscan_anon",
"pgscan_file",
"pgsteal_anon",
"pgsteal_file",
#ifdef CONFIG_NUMA
"zone_reclaim_failed",
#endif
"pginodesteal",
"slabs_scanned",
"kswapd_inodesteal",
"kswapd_low_wmark_hit_quickly",
"kswapd_high_wmark_hit_quickly",
"pageoutrun",
"pgrotated",
"drop_pagecache",
"drop_slab",
"oom_kill",
#ifdef CONFIG_NUMA_BALANCING
"numa_pte_updates",
"numa_huge_pte_updates",
"numa_hint_faults",
"numa_hint_faults_local",
"numa_pages_migrated",
#endif
#ifdef CONFIG_MIGRATION
"pgmigrate_success",
"pgmigrate_fail",
"thp_migration_success",
"thp_migration_fail",
"thp_migration_split",
#endif
#ifdef CONFIG_COMPACTION
"compact_migrate_scanned",
"compact_free_scanned",
"compact_isolated",
"compact_stall",
"compact_fail",
"compact_success",
"compact_daemon_wake",
"compact_daemon_migrate_scanned",
"compact_daemon_free_scanned",
#endif
#ifdef CONFIG_HUGETLB_PAGE
"htlb_buddy_alloc_success",
"htlb_buddy_alloc_fail",
#endif
#ifdef CONFIG_CMA
"cma_alloc_success",
"cma_alloc_fail",
#endif
"unevictable_pgs_culled",
"unevictable_pgs_scanned",
"unevictable_pgs_rescued",
"unevictable_pgs_mlocked",
"unevictable_pgs_munlocked",
"unevictable_pgs_cleared",
"unevictable_pgs_stranded",
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
"thp_fault_alloc",
"thp_fault_fallback",
"thp_fault_fallback_charge",
"thp_collapse_alloc",
"thp_collapse_alloc_failed",
"thp_file_alloc",
"thp_file_fallback",
"thp_file_fallback_charge",
"thp_file_mapped",
"thp_split_page",
"thp_split_page_failed",
"thp_deferred_split_page",
"thp_split_pmd",
"thp_scan_exceed_none_pte",
"thp_scan_exceed_swap_pte",
"thp_scan_exceed_share_pte",
#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
"thp_split_pud",
#endif
"thp_zero_page_alloc",
"thp_zero_page_alloc_failed",
"thp_swpout",
"thp_swpout_fallback",
#endif
#ifdef CONFIG_MEMORY_BALLOON
"balloon_inflate",
"balloon_deflate",
#ifdef CONFIG_BALLOON_COMPACTION
"balloon_migrate",
#endif
#endif /* CONFIG_MEMORY_BALLOON */
#ifdef CONFIG_DEBUG_TLBFLUSH
"nr_tlb_remote_flush",
"nr_tlb_remote_flush_received",
"nr_tlb_local_flush_all",
"nr_tlb_local_flush_one",
#endif /* CONFIG_DEBUG_TLBFLUSH */
#ifdef CONFIG_SWAP
"swap_ra",
"swap_ra_hit",
#ifdef CONFIG_KSM
"ksm_swpin_copy",
#endif
#endif
#ifdef CONFIG_KSM
"cow_ksm",
#endif
#ifdef CONFIG_ZSWAP
"zswpin",
"zswpout",
#endif
#ifdef CONFIG_X86
"direct_map_level2_splits",
"direct_map_level3_splits",
#endif
#ifdef CONFIG_PER_VMA_LOCK_STATS
"vma_lock_success",
"vma_lock_abort",
"vma_lock_retry",
"vma_lock_miss",
#endif
#endif /* CONFIG_VM_EVENT_COUNTERS || CONFIG_MEMCG */
};
#endif /* CONFIG_PROC_FS || CONFIG_SYSFS || CONFIG_NUMA || CONFIG_MEMCG */
#if (defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)) || \
defined(CONFIG_PROC_FS)
static void *frag_start(struct seq_file *m, loff_t *pos)
{
pg_data_t *pgdat;
loff_t node = *pos;
for (pgdat = first_online_pgdat();
pgdat && node;
pgdat = next_online_pgdat(pgdat))
--node;
return pgdat;
}
static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
{
pg_data_t *pgdat = (pg_data_t *)arg;
(*pos)++;
return next_online_pgdat(pgdat);
}
static void frag_stop(struct seq_file *m, void *arg)
{
}
/*
* Walk zones in a node and print using a callback.
* If @assert_populated is true, only use callback for zones that are populated.
*/
static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
bool assert_populated, bool nolock,
void (*print)(struct seq_file *m, pg_data_t *, struct zone *))
{
struct zone *zone;
struct zone *node_zones = pgdat->node_zones;
unsigned long flags;
for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
if (assert_populated && !populated_zone(zone))
continue;
if (!nolock)
spin_lock_irqsave(&zone->lock, flags);
print(m, pgdat, zone);
if (!nolock)
spin_unlock_irqrestore(&zone->lock, flags);
}
}
#endif
#ifdef CONFIG_PROC_FS
static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
struct zone *zone)
{
int order;
seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
for (order = 0; order <= MAX_ORDER; ++order)
/*
* Access to nr_free is lockless as nr_free is used only for
* printing purposes. Use data_race to avoid KCSAN warning.
*/
seq_printf(m, "%6lu ", data_race(zone->free_area[order].nr_free));
seq_putc(m, '\n');
}
/*
* This walks the free areas for each zone.
*/
static int frag_show(struct seq_file *m, void *arg)
{
pg_data_t *pgdat = (pg_data_t *)arg;
walk_zones_in_node(m, pgdat, true, false, frag_show_print);
return 0;
}
static void pagetypeinfo_showfree_print(struct seq_file *m,
pg_data_t *pgdat, struct zone *zone)
{
int order, mtype;
for (mtype = 0; mtype < MIGRATE_TYPES; mtype++) {
seq_printf(m, "Node %4d, zone %8s, type %12s ",
pgdat->node_id,
zone->name,
migratetype_names[mtype]);
for (order = 0; order <= MAX_ORDER; ++order) {
unsigned long freecount = 0;
struct free_area *area;
struct list_head *curr;
bool overflow = false;
area = &(zone->free_area[order]);
list_for_each(curr, &area->free_list[mtype]) {
/*
* Cap the free_list iteration because it might
* be really large and we are under a spinlock
* so a long time spent here could trigger a
* hard lockup detector. Anyway this is a
* debugging tool so knowing there is a handful
* of pages of this order should be more than
* sufficient.
*/
if (++freecount >= 100000) {
overflow = true;
break;
}
}
seq_printf(m, "%s%6lu ", overflow ? ">" : "", freecount);
spin_unlock_irq(&zone->lock);
cond_resched();
spin_lock_irq(&zone->lock);
}
seq_putc(m, '\n');
}
}
/* Print out the free pages at each order for each migatetype */
static void pagetypeinfo_showfree(struct seq_file *m, void *arg)
{
int order;
pg_data_t *pgdat = (pg_data_t *)arg;
/* Print header */
seq_printf(m, "%-43s ", "Free pages count per migrate type at order");
for (order = 0; order <= MAX_ORDER; ++order)
seq_printf(m, "%6d ", order);
seq_putc(m, '\n');
walk_zones_in_node(m, pgdat, true, false, pagetypeinfo_showfree_print);
}
static void pagetypeinfo_showblockcount_print(struct seq_file *m,
pg_data_t *pgdat, struct zone *zone)
{
int mtype;
unsigned long pfn;
unsigned long start_pfn = zone->zone_start_pfn;
unsigned long end_pfn = zone_end_pfn(zone);
unsigned long count[MIGRATE_TYPES] = { 0, };
for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
struct page *page;
page = pfn_to_online_page(pfn);
if (!page)
continue;
if (page_zone(page) != zone)
continue;
mtype = get_pageblock_migratetype(page);
if (mtype < MIGRATE_TYPES)
count[mtype]++;
}
/* Print counts */
seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
seq_printf(m, "%12lu ", count[mtype]);
seq_putc(m, '\n');
}
/* Print out the number of pageblocks for each migratetype */
static void pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
{
int mtype;
pg_data_t *pgdat = (pg_data_t *)arg;
seq_printf(m, "\n%-23s", "Number of blocks type ");
for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
seq_printf(m, "%12s ", migratetype_names[mtype]);
seq_putc(m, '\n');
walk_zones_in_node(m, pgdat, true, false,
pagetypeinfo_showblockcount_print);
}
/*
* Print out the number of pageblocks for each migratetype that contain pages
* of other types. This gives an indication of how well fallbacks are being
* contained by rmqueue_fallback(). It requires information from PAGE_OWNER
* to determine what is going on
*/
static void pagetypeinfo_showmixedcount(struct seq_file *m, pg_data_t *pgdat)
{
#ifdef CONFIG_PAGE_OWNER
int mtype;
if (!static_branch_unlikely(&page_owner_inited))
return;
drain_all_pages(NULL);
seq_printf(m, "\n%-23s", "Number of mixed blocks ");
for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
seq_printf(m, "%12s ", migratetype_names[mtype]);
seq_putc(m, '\n');
walk_zones_in_node(m, pgdat, true, true,
pagetypeinfo_showmixedcount_print);
#endif /* CONFIG_PAGE_OWNER */
}
/*
* This prints out statistics in relation to grouping pages by mobility.
* It is expensive to collect so do not constantly read the file.
*/
static int pagetypeinfo_show(struct seq_file *m, void *arg)
{
pg_data_t *pgdat = (pg_data_t *)arg;
/* check memoryless node */
if (!node_state(pgdat->node_id, N_MEMORY))
return 0;
seq_printf(m, "Page block order: %d\n", pageblock_order);
seq_printf(m, "Pages per block: %lu\n", pageblock_nr_pages);
seq_putc(m, '\n');
pagetypeinfo_showfree(m, pgdat);
pagetypeinfo_showblockcount(m, pgdat);
pagetypeinfo_showmixedcount(m, pgdat);
return 0;
}
static const struct seq_operations fragmentation_op = {
.start = frag_start,
.next = frag_next,
.stop = frag_stop,
.show = frag_show,
};
static const struct seq_operations pagetypeinfo_op = {
.start = frag_start,
.next = frag_next,
.stop = frag_stop,
.show = pagetypeinfo_show,
};
static bool is_zone_first_populated(pg_data_t *pgdat, struct zone *zone)
{
int zid;
for (zid = 0; zid < MAX_NR_ZONES; zid++) {
struct zone *compare = &pgdat->node_zones[zid];
if (populated_zone(compare))
return zone == compare;
}
return false;
}
static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
struct zone *zone)
{
int i;
seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
if (is_zone_first_populated(pgdat, zone)) {
seq_printf(m, "\n per-node stats");
for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
unsigned long pages = node_page_state_pages(pgdat, i);
if (vmstat_item_print_in_thp(i))
pages /= HPAGE_PMD_NR;
seq_printf(m, "\n %-12s %lu", node_stat_name(i),
pages);
}
}
seq_printf(m,
"\n pages free %lu"
"\n boost %lu"
"\n min %lu"
"\n low %lu"
"\n high %lu"
"\n spanned %lu"
"\n present %lu"
"\n managed %lu"
"\n cma %lu",
zone_page_state(zone, NR_FREE_PAGES),
zone->watermark_boost,
min_wmark_pages(zone),
low_wmark_pages(zone),
high_wmark_pages(zone),
zone->spanned_pages,
zone->present_pages,
zone_managed_pages(zone),
zone_cma_pages(zone));
seq_printf(m,
"\n protection: (%ld",
zone->lowmem_reserve[0]);
for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
seq_printf(m, ", %ld", zone->lowmem_reserve[i]);
seq_putc(m, ')');
/* If unpopulated, no other information is useful */
if (!populated_zone(zone)) {
seq_putc(m, '\n');
return;
}
for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
seq_printf(m, "\n %-12s %lu", zone_stat_name(i),
zone_page_state(zone, i));
#ifdef CONFIG_NUMA
for (i = 0; i < NR_VM_NUMA_EVENT_ITEMS; i++)
seq_printf(m, "\n %-12s %lu", numa_stat_name(i),
zone_numa_event_state(zone, i));
#endif
seq_printf(m, "\n pagesets");
for_each_online_cpu(i) {
struct per_cpu_pages *pcp;
struct per_cpu_zonestat __maybe_unused *pzstats;
pcp = per_cpu_ptr(zone->per_cpu_pageset, i);
seq_printf(m,
"\n cpu: %i"
"\n count: %i"
"\n high: %i"
"\n batch: %i",
i,
pcp->count,
pcp->high,
pcp->batch);
#ifdef CONFIG_SMP
pzstats = per_cpu_ptr(zone->per_cpu_zonestats, i);
seq_printf(m, "\n vm stats threshold: %d",
pzstats->stat_threshold);
#endif
}
seq_printf(m,
"\n node_unreclaimable: %u"
"\n start_pfn: %lu",
pgdat->kswapd_failures >= MAX_RECLAIM_RETRIES,
zone->zone_start_pfn);
seq_putc(m, '\n');
}
/*
* Output information about zones in @pgdat. All zones are printed regardless
* of whether they are populated or not: lowmem_reserve_ratio operates on the
* set of all zones and userspace would not be aware of such zones if they are
* suppressed here (zoneinfo displays the effect of lowmem_reserve_ratio).
*/
static int zoneinfo_show(struct seq_file *m, void *arg)
{
pg_data_t *pgdat = (pg_data_t *)arg;
walk_zones_in_node(m, pgdat, false, false, zoneinfo_show_print);
return 0;
}
static const struct seq_operations zoneinfo_op = {
.start = frag_start, /* iterate over all zones. The same as in
* fragmentation. */
.next = frag_next,
.stop = frag_stop,
.show = zoneinfo_show,
};
#define NR_VMSTAT_ITEMS (NR_VM_ZONE_STAT_ITEMS + \
NR_VM_NUMA_EVENT_ITEMS + \
NR_VM_NODE_STAT_ITEMS + \
NR_VM_WRITEBACK_STAT_ITEMS + \
(IS_ENABLED(CONFIG_VM_EVENT_COUNTERS) ? \
NR_VM_EVENT_ITEMS : 0))
static void *vmstat_start(struct seq_file *m, loff_t *pos)
{
unsigned long *v;
int i;
if (*pos >= NR_VMSTAT_ITEMS)
return NULL;
BUILD_BUG_ON(ARRAY_SIZE(vmstat_text) < NR_VMSTAT_ITEMS);
fold_vm_numa_events();
v = kmalloc_array(NR_VMSTAT_ITEMS, sizeof(unsigned long), GFP_KERNEL);
m->private = v;
if (!v)
return ERR_PTR(-ENOMEM);
for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
v[i] = global_zone_page_state(i);
v += NR_VM_ZONE_STAT_ITEMS;
#ifdef CONFIG_NUMA
for (i = 0; i < NR_VM_NUMA_EVENT_ITEMS; i++)
v[i] = global_numa_event_state(i);
v += NR_VM_NUMA_EVENT_ITEMS;
#endif
for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
v[i] = global_node_page_state_pages(i);
if (vmstat_item_print_in_thp(i))
v[i] /= HPAGE_PMD_NR;
}
v += NR_VM_NODE_STAT_ITEMS;
global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD,
v + NR_DIRTY_THRESHOLD);
v += NR_VM_WRITEBACK_STAT_ITEMS;
#ifdef CONFIG_VM_EVENT_COUNTERS
all_vm_events(v);
v[PGPGIN] /= 2; /* sectors -> kbytes */
v[PGPGOUT] /= 2;
#endif
return (unsigned long *)m->private + *pos;
}
static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
{
(*pos)++;
if (*pos >= NR_VMSTAT_ITEMS)
return NULL;
return (unsigned long *)m->private + *pos;
}
static int vmstat_show(struct seq_file *m, void *arg)
{
unsigned long *l = arg;
unsigned long off = l - (unsigned long *)m->private;
seq_puts(m, vmstat_text[off]);
seq_put_decimal_ull(m, " ", *l);
seq_putc(m, '\n');
if (off == NR_VMSTAT_ITEMS - 1) {
/*
* We've come to the end - add any deprecated counters to avoid
* breaking userspace which might depend on them being present.
*/
seq_puts(m, "nr_unstable 0\n");
}
return 0;
}
static void vmstat_stop(struct seq_file *m, void *arg)
{
kfree(m->private);
m->private = NULL;
}
static const struct seq_operations vmstat_op = {
.start = vmstat_start,
.next = vmstat_next,
.stop = vmstat_stop,
.show = vmstat_show,
};
#endif /* CONFIG_PROC_FS */
#ifdef CONFIG_SMP
static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
int sysctl_stat_interval __read_mostly = HZ;
#ifdef CONFIG_PROC_FS
static void refresh_vm_stats(struct work_struct *work)
{
refresh_cpu_vm_stats(true);
}
int vmstat_refresh(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
long val;
int err;
int i;
/*
* The regular update, every sysctl_stat_interval, may come later
* than expected: leaving a significant amount in per_cpu buckets.
* This is particularly misleading when checking a quantity of HUGE
* pages, immediately after running a test. /proc/sys/vm/stat_refresh,
* which can equally be echo'ed to or cat'ted from (by root),
* can be used to update the stats just before reading them.
*
* Oh, and since global_zone_page_state() etc. are so careful to hide
* transiently negative values, report an error here if any of
* the stats is negative, so we know to go looking for imbalance.
*/
err = schedule_on_each_cpu(refresh_vm_stats);
if (err)
return err;
for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
/*
* Skip checking stats known to go negative occasionally.
*/
switch (i) {
case NR_ZONE_WRITE_PENDING:
case NR_FREE_CMA_PAGES:
continue;
}
val = atomic_long_read(&vm_zone_stat[i]);
if (val < 0) {
pr_warn("%s: %s %ld\n",
__func__, zone_stat_name(i), val);
}
}
for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
/*
* Skip checking stats known to go negative occasionally.
*/
switch (i) {
case NR_WRITEBACK:
continue;
}
val = atomic_long_read(&vm_node_stat[i]);
if (val < 0) {
pr_warn("%s: %s %ld\n",
__func__, node_stat_name(i), val);
}
}
if (write)
*ppos += *lenp;
else
*lenp = 0;
return 0;
}
#endif /* CONFIG_PROC_FS */
static void vmstat_update(struct work_struct *w)
{
if (refresh_cpu_vm_stats(true)) {
/*
* Counters were updated so we expect more updates
* to occur in the future. Keep on running the
* update worker thread.
*/
queue_delayed_work_on(smp_processor_id(), mm_percpu_wq,
this_cpu_ptr(&vmstat_work),
round_jiffies_relative(sysctl_stat_interval));
}
}
/*
* Check if the diffs for a certain cpu indicate that
* an update is needed.
*/
static bool need_update(int cpu)
{
pg_data_t *last_pgdat = NULL;
struct zone *zone;
for_each_populated_zone(zone) {
struct per_cpu_zonestat *pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu);
struct per_cpu_nodestat *n;
/*
* The fast way of checking if there are any vmstat diffs.
*/
if (memchr_inv(pzstats->vm_stat_diff, 0, sizeof(pzstats->vm_stat_diff)))
return true;
if (last_pgdat == zone->zone_pgdat)
continue;
last_pgdat = zone->zone_pgdat;
n = per_cpu_ptr(zone->zone_pgdat->per_cpu_nodestats, cpu);
if (memchr_inv(n->vm_node_stat_diff, 0, sizeof(n->vm_node_stat_diff)))
return true;
}
return false;
}
/*
* Switch off vmstat processing and then fold all the remaining differentials
* until the diffs stay at zero. The function is used by NOHZ and can only be
* invoked when tick processing is not active.
*/
void quiet_vmstat(void)
{
if (system_state != SYSTEM_RUNNING)
return;
if (!delayed_work_pending(this_cpu_ptr(&vmstat_work)))
return;
if (!need_update(smp_processor_id()))
return;
/*
* Just refresh counters and do not care about the pending delayed
* vmstat_update. It doesn't fire that often to matter and canceling
* it would be too expensive from this path.
* vmstat_shepherd will take care about that for us.
*/
refresh_cpu_vm_stats(false);
}
/*
* Shepherd worker thread that checks the
* differentials of processors that have their worker
* threads for vm statistics updates disabled because of
* inactivity.
*/
static void vmstat_shepherd(struct work_struct *w);
static DECLARE_DEFERRABLE_WORK(shepherd, vmstat_shepherd);
static void vmstat_shepherd(struct work_struct *w)
{
int cpu;
cpus_read_lock();
/* Check processors whose vmstat worker threads have been disabled */
for_each_online_cpu(cpu) {
struct delayed_work *dw = &per_cpu(vmstat_work, cpu);
/*
* In kernel users of vmstat counters either require the precise value and
* they are using zone_page_state_snapshot interface or they can live with
* an imprecision as the regular flushing can happen at arbitrary time and
* cumulative error can grow (see calculate_normal_threshold).
*
* From that POV the regular flushing can be postponed for CPUs that have
* been isolated from the kernel interference without critical
* infrastructure ever noticing. Skip regular flushing from vmstat_shepherd
* for all isolated CPUs to avoid interference with the isolated workload.
*/
if (cpu_is_isolated(cpu))
continue;
if (!delayed_work_pending(dw) && need_update(cpu))
queue_delayed_work_on(cpu, mm_percpu_wq, dw, 0);
cond_resched();
}
cpus_read_unlock();
schedule_delayed_work(&shepherd,
round_jiffies_relative(sysctl_stat_interval));
}
static void __init start_shepherd_timer(void)
{
int cpu;
for_each_possible_cpu(cpu)
INIT_DEFERRABLE_WORK(per_cpu_ptr(&vmstat_work, cpu),
vmstat_update);
schedule_delayed_work(&shepherd,
round_jiffies_relative(sysctl_stat_interval));
}
static void __init init_cpu_node_state(void)
{
int node;
for_each_online_node(node) {
if (!cpumask_empty(cpumask_of_node(node)))
node_set_state(node, N_CPU);
}
}
static int vmstat_cpu_online(unsigned int cpu)
{
refresh_zone_stat_thresholds();
if (!node_state(cpu_to_node(cpu), N_CPU)) {
node_set_state(cpu_to_node(cpu), N_CPU);
}
return 0;
}
static int vmstat_cpu_down_prep(unsigned int cpu)
{
cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu));
return 0;
}
static int vmstat_cpu_dead(unsigned int cpu)
{
const struct cpumask *node_cpus;
int node;
node = cpu_to_node(cpu);
refresh_zone_stat_thresholds();
node_cpus = cpumask_of_node(node);
if (!cpumask_empty(node_cpus))
return 0;
node_clear_state(node, N_CPU);
return 0;
}
#endif
struct workqueue_struct *mm_percpu_wq;
void __init init_mm_internals(void)
{
int ret __maybe_unused;
mm_percpu_wq = alloc_workqueue("mm_percpu_wq", WQ_MEM_RECLAIM, 0);
#ifdef CONFIG_SMP
ret = cpuhp_setup_state_nocalls(CPUHP_MM_VMSTAT_DEAD, "mm/vmstat:dead",
NULL, vmstat_cpu_dead);
if (ret < 0)
pr_err("vmstat: failed to register 'dead' hotplug state\n");
ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "mm/vmstat:online",
vmstat_cpu_online,
vmstat_cpu_down_prep);
if (ret < 0)
pr_err("vmstat: failed to register 'online' hotplug state\n");
cpus_read_lock();
init_cpu_node_state();
cpus_read_unlock();
start_shepherd_timer();
#endif
#ifdef CONFIG_PROC_FS
proc_create_seq("buddyinfo", 0444, NULL, &fragmentation_op);
proc_create_seq("pagetypeinfo", 0400, NULL, &pagetypeinfo_op);
proc_create_seq("vmstat", 0444, NULL, &vmstat_op);
proc_create_seq("zoneinfo", 0444, NULL, &zoneinfo_op);
#endif
}
#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)
/*
* Return an index indicating how much of the available free memory is
* unusable for an allocation of the requested size.
*/
static int unusable_free_index(unsigned int order,
struct contig_page_info *info)
{
/* No free memory is interpreted as all free memory is unusable */
if (info->free_pages == 0)
return 1000;
/*
* Index should be a value between 0 and 1. Return a value to 3
* decimal places.
*
* 0 => no fragmentation
* 1 => high fragmentation
*/
return div_u64((info->free_pages - (info->free_blocks_suitable << order)) * 1000ULL, info->free_pages);
}
static void unusable_show_print(struct seq_file *m,
pg_data_t *pgdat, struct zone *zone)
{
unsigned int order;
int index;
struct contig_page_info info;
seq_printf(m, "Node %d, zone %8s ",
pgdat->node_id,
zone->name);
for (order = 0; order <= MAX_ORDER; ++order) {
fill_contig_page_info(zone, order, &info);
index = unusable_free_index(order, &info);
seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
}
seq_putc(m, '\n');
}
/*
* Display unusable free space index
*
* The unusable free space index measures how much of the available free
* memory cannot be used to satisfy an allocation of a given size and is a
* value between 0 and 1. The higher the value, the more of free memory is
* unusable and by implication, the worse the external fragmentation is. This
* can be expressed as a percentage by multiplying by 100.
*/
static int unusable_show(struct seq_file *m, void *arg)
{
pg_data_t *pgdat = (pg_data_t *)arg;
/* check memoryless node */
if (!node_state(pgdat->node_id, N_MEMORY))
return 0;
walk_zones_in_node(m, pgdat, true, false, unusable_show_print);
return 0;
}
static const struct seq_operations unusable_sops = {
.start = frag_start,
.next = frag_next,
.stop = frag_stop,
.show = unusable_show,
};
DEFINE_SEQ_ATTRIBUTE(unusable);
static void extfrag_show_print(struct seq_file *m,
pg_data_t *pgdat, struct zone *zone)
{
unsigned int order;
int index;
/* Alloc on stack as interrupts are disabled for zone walk */
struct contig_page_info info;
seq_printf(m, "Node %d, zone %8s ",
pgdat->node_id,
zone->name);
for (order = 0; order <= MAX_ORDER; ++order) {
fill_contig_page_info(zone, order, &info);
index = __fragmentation_index(order, &info);
seq_printf(m, "%2d.%03d ", index / 1000, index % 1000);
}
seq_putc(m, '\n');
}
/*
* Display fragmentation index for orders that allocations would fail for
*/
static int extfrag_show(struct seq_file *m, void *arg)
{
pg_data_t *pgdat = (pg_data_t *)arg;
walk_zones_in_node(m, pgdat, true, false, extfrag_show_print);
return 0;
}
static const struct seq_operations extfrag_sops = {
.start = frag_start,
.next = frag_next,
.stop = frag_stop,
.show = extfrag_show,
};
DEFINE_SEQ_ATTRIBUTE(extfrag);
static int __init extfrag_debug_init(void)
{
struct dentry *extfrag_debug_root;
extfrag_debug_root = debugfs_create_dir("extfrag", NULL);
debugfs_create_file("unusable_index", 0444, extfrag_debug_root, NULL,
&unusable_fops);
debugfs_create_file("extfrag_index", 0444, extfrag_debug_root, NULL,
&extfrag_fops);
return 0;
}
module_init(extfrag_debug_init);
#endif
| linux-master | mm/vmstat.c |
// SPDX-License-Identifier: GPL-2.0
/*
* linux/mm/msync.c
*
* Copyright (C) 1994-1999 Linus Torvalds
*/
/*
* The msync() system call.
*/
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/file.h>
#include <linux/syscalls.h>
#include <linux/sched.h>
/*
* MS_SYNC syncs the entire file - including mappings.
*
* MS_ASYNC does not start I/O (it used to, up to 2.5.67).
* Nor does it marks the relevant pages dirty (it used to up to 2.6.17).
* Now it doesn't do anything, since dirty pages are properly tracked.
*
* The application may now run fsync() to
* write out the dirty pages and wait on the writeout and check the result.
* Or the application may run fadvise(FADV_DONTNEED) against the fd to start
* async writeout immediately.
* So by _not_ starting I/O in MS_ASYNC we provide complete flexibility to
* applications.
*/
SYSCALL_DEFINE3(msync, unsigned long, start, size_t, len, int, flags)
{
unsigned long end;
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
int unmapped_error = 0;
int error = -EINVAL;
start = untagged_addr(start);
if (flags & ~(MS_ASYNC | MS_INVALIDATE | MS_SYNC))
goto out;
if (offset_in_page(start))
goto out;
if ((flags & MS_ASYNC) && (flags & MS_SYNC))
goto out;
error = -ENOMEM;
len = (len + ~PAGE_MASK) & PAGE_MASK;
end = start + len;
if (end < start)
goto out;
error = 0;
if (end == start)
goto out;
/*
* If the interval [start,end) covers some unmapped address ranges,
* just ignore them, but return -ENOMEM at the end. Besides, if the
* flag is MS_ASYNC (w/o MS_INVALIDATE) the result would be -ENOMEM
* anyway and there is nothing left to do, so return immediately.
*/
mmap_read_lock(mm);
vma = find_vma(mm, start);
for (;;) {
struct file *file;
loff_t fstart, fend;
/* Still start < end. */
error = -ENOMEM;
if (!vma)
goto out_unlock;
/* Here start < vma->vm_end. */
if (start < vma->vm_start) {
if (flags == MS_ASYNC)
goto out_unlock;
start = vma->vm_start;
if (start >= end)
goto out_unlock;
unmapped_error = -ENOMEM;
}
/* Here vma->vm_start <= start < vma->vm_end. */
if ((flags & MS_INVALIDATE) &&
(vma->vm_flags & VM_LOCKED)) {
error = -EBUSY;
goto out_unlock;
}
file = vma->vm_file;
fstart = (start - vma->vm_start) +
((loff_t)vma->vm_pgoff << PAGE_SHIFT);
fend = fstart + (min(end, vma->vm_end) - start) - 1;
start = vma->vm_end;
if ((flags & MS_SYNC) && file &&
(vma->vm_flags & VM_SHARED)) {
get_file(file);
mmap_read_unlock(mm);
error = vfs_fsync_range(file, fstart, fend, 1);
fput(file);
if (error || start >= end)
goto out;
mmap_read_lock(mm);
vma = find_vma(mm, start);
} else {
if (start >= end) {
error = 0;
goto out_unlock;
}
vma = find_vma(mm, vma->vm_end);
}
}
out_unlock:
mmap_read_unlock(mm);
out:
return error ? : unmapped_error;
}
| linux-master | mm/msync.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/mm.h>
#include <linux/page-isolation.h>
unsigned int _debug_guardpage_minorder;
bool _debug_pagealloc_enabled_early __read_mostly
= IS_ENABLED(CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT);
EXPORT_SYMBOL(_debug_pagealloc_enabled_early);
DEFINE_STATIC_KEY_FALSE(_debug_pagealloc_enabled);
EXPORT_SYMBOL(_debug_pagealloc_enabled);
DEFINE_STATIC_KEY_FALSE(_debug_guardpage_enabled);
static int __init early_debug_pagealloc(char *buf)
{
return kstrtobool(buf, &_debug_pagealloc_enabled_early);
}
early_param("debug_pagealloc", early_debug_pagealloc);
static int __init debug_guardpage_minorder_setup(char *buf)
{
unsigned long res;
if (kstrtoul(buf, 10, &res) < 0 || res > MAX_ORDER / 2) {
pr_err("Bad debug_guardpage_minorder value\n");
return 0;
}
_debug_guardpage_minorder = res;
pr_info("Setting debug_guardpage_minorder to %lu\n", res);
return 0;
}
early_param("debug_guardpage_minorder", debug_guardpage_minorder_setup);
bool __set_page_guard(struct zone *zone, struct page *page, unsigned int order,
int migratetype)
{
if (order >= debug_guardpage_minorder())
return false;
__SetPageGuard(page);
INIT_LIST_HEAD(&page->buddy_list);
set_page_private(page, order);
/* Guard pages are not available for any usage */
if (!is_migrate_isolate(migratetype))
__mod_zone_freepage_state(zone, -(1 << order), migratetype);
return true;
}
void __clear_page_guard(struct zone *zone, struct page *page, unsigned int order,
int migratetype)
{
__ClearPageGuard(page);
set_page_private(page, 0);
if (!is_migrate_isolate(migratetype))
__mod_zone_freepage_state(zone, (1 << order), migratetype);
}
| linux-master | mm/debug_page_alloc.c |
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright 2013 Red Hat Inc.
*
* Authors: Jérôme Glisse <[email protected]>
*/
/*
* Refer to include/linux/hmm.h for information about heterogeneous memory
* management or HMM for short.
*/
#include <linux/pagewalk.h>
#include <linux/hmm.h>
#include <linux/init.h>
#include <linux/rmap.h>
#include <linux/swap.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/mmzone.h>
#include <linux/pagemap.h>
#include <linux/swapops.h>
#include <linux/hugetlb.h>
#include <linux/memremap.h>
#include <linux/sched/mm.h>
#include <linux/jump_label.h>
#include <linux/dma-mapping.h>
#include <linux/mmu_notifier.h>
#include <linux/memory_hotplug.h>
#include "internal.h"
struct hmm_vma_walk {
struct hmm_range *range;
unsigned long last;
};
enum {
HMM_NEED_FAULT = 1 << 0,
HMM_NEED_WRITE_FAULT = 1 << 1,
HMM_NEED_ALL_BITS = HMM_NEED_FAULT | HMM_NEED_WRITE_FAULT,
};
static int hmm_pfns_fill(unsigned long addr, unsigned long end,
struct hmm_range *range, unsigned long cpu_flags)
{
unsigned long i = (addr - range->start) >> PAGE_SHIFT;
for (; addr < end; addr += PAGE_SIZE, i++)
range->hmm_pfns[i] = cpu_flags;
return 0;
}
/*
* hmm_vma_fault() - fault in a range lacking valid pmd or pte(s)
* @addr: range virtual start address (inclusive)
* @end: range virtual end address (exclusive)
* @required_fault: HMM_NEED_* flags
* @walk: mm_walk structure
* Return: -EBUSY after page fault, or page fault error
*
* This function will be called whenever pmd_none() or pte_none() returns true,
* or whenever there is no page directory covering the virtual address range.
*/
static int hmm_vma_fault(unsigned long addr, unsigned long end,
unsigned int required_fault, struct mm_walk *walk)
{
struct hmm_vma_walk *hmm_vma_walk = walk->private;
struct vm_area_struct *vma = walk->vma;
unsigned int fault_flags = FAULT_FLAG_REMOTE;
WARN_ON_ONCE(!required_fault);
hmm_vma_walk->last = addr;
if (required_fault & HMM_NEED_WRITE_FAULT) {
if (!(vma->vm_flags & VM_WRITE))
return -EPERM;
fault_flags |= FAULT_FLAG_WRITE;
}
for (; addr < end; addr += PAGE_SIZE)
if (handle_mm_fault(vma, addr, fault_flags, NULL) &
VM_FAULT_ERROR)
return -EFAULT;
return -EBUSY;
}
static unsigned int hmm_pte_need_fault(const struct hmm_vma_walk *hmm_vma_walk,
unsigned long pfn_req_flags,
unsigned long cpu_flags)
{
struct hmm_range *range = hmm_vma_walk->range;
/*
* So we not only consider the individual per page request we also
* consider the default flags requested for the range. The API can
* be used 2 ways. The first one where the HMM user coalesces
* multiple page faults into one request and sets flags per pfn for
* those faults. The second one where the HMM user wants to pre-
* fault a range with specific flags. For the latter one it is a
* waste to have the user pre-fill the pfn arrays with a default
* flags value.
*/
pfn_req_flags &= range->pfn_flags_mask;
pfn_req_flags |= range->default_flags;
/* We aren't ask to do anything ... */
if (!(pfn_req_flags & HMM_PFN_REQ_FAULT))
return 0;
/* Need to write fault ? */
if ((pfn_req_flags & HMM_PFN_REQ_WRITE) &&
!(cpu_flags & HMM_PFN_WRITE))
return HMM_NEED_FAULT | HMM_NEED_WRITE_FAULT;
/* If CPU page table is not valid then we need to fault */
if (!(cpu_flags & HMM_PFN_VALID))
return HMM_NEED_FAULT;
return 0;
}
static unsigned int
hmm_range_need_fault(const struct hmm_vma_walk *hmm_vma_walk,
const unsigned long hmm_pfns[], unsigned long npages,
unsigned long cpu_flags)
{
struct hmm_range *range = hmm_vma_walk->range;
unsigned int required_fault = 0;
unsigned long i;
/*
* If the default flags do not request to fault pages, and the mask does
* not allow for individual pages to be faulted, then
* hmm_pte_need_fault() will always return 0.
*/
if (!((range->default_flags | range->pfn_flags_mask) &
HMM_PFN_REQ_FAULT))
return 0;
for (i = 0; i < npages; ++i) {
required_fault |= hmm_pte_need_fault(hmm_vma_walk, hmm_pfns[i],
cpu_flags);
if (required_fault == HMM_NEED_ALL_BITS)
return required_fault;
}
return required_fault;
}
static int hmm_vma_walk_hole(unsigned long addr, unsigned long end,
__always_unused int depth, struct mm_walk *walk)
{
struct hmm_vma_walk *hmm_vma_walk = walk->private;
struct hmm_range *range = hmm_vma_walk->range;
unsigned int required_fault;
unsigned long i, npages;
unsigned long *hmm_pfns;
i = (addr - range->start) >> PAGE_SHIFT;
npages = (end - addr) >> PAGE_SHIFT;
hmm_pfns = &range->hmm_pfns[i];
required_fault =
hmm_range_need_fault(hmm_vma_walk, hmm_pfns, npages, 0);
if (!walk->vma) {
if (required_fault)
return -EFAULT;
return hmm_pfns_fill(addr, end, range, HMM_PFN_ERROR);
}
if (required_fault)
return hmm_vma_fault(addr, end, required_fault, walk);
return hmm_pfns_fill(addr, end, range, 0);
}
static inline unsigned long hmm_pfn_flags_order(unsigned long order)
{
return order << HMM_PFN_ORDER_SHIFT;
}
static inline unsigned long pmd_to_hmm_pfn_flags(struct hmm_range *range,
pmd_t pmd)
{
if (pmd_protnone(pmd))
return 0;
return (pmd_write(pmd) ? (HMM_PFN_VALID | HMM_PFN_WRITE) :
HMM_PFN_VALID) |
hmm_pfn_flags_order(PMD_SHIFT - PAGE_SHIFT);
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static int hmm_vma_handle_pmd(struct mm_walk *walk, unsigned long addr,
unsigned long end, unsigned long hmm_pfns[],
pmd_t pmd)
{
struct hmm_vma_walk *hmm_vma_walk = walk->private;
struct hmm_range *range = hmm_vma_walk->range;
unsigned long pfn, npages, i;
unsigned int required_fault;
unsigned long cpu_flags;
npages = (end - addr) >> PAGE_SHIFT;
cpu_flags = pmd_to_hmm_pfn_flags(range, pmd);
required_fault =
hmm_range_need_fault(hmm_vma_walk, hmm_pfns, npages, cpu_flags);
if (required_fault)
return hmm_vma_fault(addr, end, required_fault, walk);
pfn = pmd_pfn(pmd) + ((addr & ~PMD_MASK) >> PAGE_SHIFT);
for (i = 0; addr < end; addr += PAGE_SIZE, i++, pfn++)
hmm_pfns[i] = pfn | cpu_flags;
return 0;
}
#else /* CONFIG_TRANSPARENT_HUGEPAGE */
/* stub to allow the code below to compile */
int hmm_vma_handle_pmd(struct mm_walk *walk, unsigned long addr,
unsigned long end, unsigned long hmm_pfns[], pmd_t pmd);
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
static inline unsigned long pte_to_hmm_pfn_flags(struct hmm_range *range,
pte_t pte)
{
if (pte_none(pte) || !pte_present(pte) || pte_protnone(pte))
return 0;
return pte_write(pte) ? (HMM_PFN_VALID | HMM_PFN_WRITE) : HMM_PFN_VALID;
}
static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr,
unsigned long end, pmd_t *pmdp, pte_t *ptep,
unsigned long *hmm_pfn)
{
struct hmm_vma_walk *hmm_vma_walk = walk->private;
struct hmm_range *range = hmm_vma_walk->range;
unsigned int required_fault;
unsigned long cpu_flags;
pte_t pte = ptep_get(ptep);
uint64_t pfn_req_flags = *hmm_pfn;
if (pte_none_mostly(pte)) {
required_fault =
hmm_pte_need_fault(hmm_vma_walk, pfn_req_flags, 0);
if (required_fault)
goto fault;
*hmm_pfn = 0;
return 0;
}
if (!pte_present(pte)) {
swp_entry_t entry = pte_to_swp_entry(pte);
/*
* Don't fault in device private pages owned by the caller,
* just report the PFN.
*/
if (is_device_private_entry(entry) &&
pfn_swap_entry_to_page(entry)->pgmap->owner ==
range->dev_private_owner) {
cpu_flags = HMM_PFN_VALID;
if (is_writable_device_private_entry(entry))
cpu_flags |= HMM_PFN_WRITE;
*hmm_pfn = swp_offset_pfn(entry) | cpu_flags;
return 0;
}
required_fault =
hmm_pte_need_fault(hmm_vma_walk, pfn_req_flags, 0);
if (!required_fault) {
*hmm_pfn = 0;
return 0;
}
if (!non_swap_entry(entry))
goto fault;
if (is_device_private_entry(entry))
goto fault;
if (is_device_exclusive_entry(entry))
goto fault;
if (is_migration_entry(entry)) {
pte_unmap(ptep);
hmm_vma_walk->last = addr;
migration_entry_wait(walk->mm, pmdp, addr);
return -EBUSY;
}
/* Report error for everything else */
pte_unmap(ptep);
return -EFAULT;
}
cpu_flags = pte_to_hmm_pfn_flags(range, pte);
required_fault =
hmm_pte_need_fault(hmm_vma_walk, pfn_req_flags, cpu_flags);
if (required_fault)
goto fault;
/*
* Bypass devmap pte such as DAX page when all pfn requested
* flags(pfn_req_flags) are fulfilled.
* Since each architecture defines a struct page for the zero page, just
* fall through and treat it like a normal page.
*/
if (!vm_normal_page(walk->vma, addr, pte) &&
!pte_devmap(pte) &&
!is_zero_pfn(pte_pfn(pte))) {
if (hmm_pte_need_fault(hmm_vma_walk, pfn_req_flags, 0)) {
pte_unmap(ptep);
return -EFAULT;
}
*hmm_pfn = HMM_PFN_ERROR;
return 0;
}
*hmm_pfn = pte_pfn(pte) | cpu_flags;
return 0;
fault:
pte_unmap(ptep);
/* Fault any virtual address we were asked to fault */
return hmm_vma_fault(addr, end, required_fault, walk);
}
static int hmm_vma_walk_pmd(pmd_t *pmdp,
unsigned long start,
unsigned long end,
struct mm_walk *walk)
{
struct hmm_vma_walk *hmm_vma_walk = walk->private;
struct hmm_range *range = hmm_vma_walk->range;
unsigned long *hmm_pfns =
&range->hmm_pfns[(start - range->start) >> PAGE_SHIFT];
unsigned long npages = (end - start) >> PAGE_SHIFT;
unsigned long addr = start;
pte_t *ptep;
pmd_t pmd;
again:
pmd = pmdp_get_lockless(pmdp);
if (pmd_none(pmd))
return hmm_vma_walk_hole(start, end, -1, walk);
if (thp_migration_supported() && is_pmd_migration_entry(pmd)) {
if (hmm_range_need_fault(hmm_vma_walk, hmm_pfns, npages, 0)) {
hmm_vma_walk->last = addr;
pmd_migration_entry_wait(walk->mm, pmdp);
return -EBUSY;
}
return hmm_pfns_fill(start, end, range, 0);
}
if (!pmd_present(pmd)) {
if (hmm_range_need_fault(hmm_vma_walk, hmm_pfns, npages, 0))
return -EFAULT;
return hmm_pfns_fill(start, end, range, HMM_PFN_ERROR);
}
if (pmd_devmap(pmd) || pmd_trans_huge(pmd)) {
/*
* No need to take pmd_lock here, even if some other thread
* is splitting the huge pmd we will get that event through
* mmu_notifier callback.
*
* So just read pmd value and check again it's a transparent
* huge or device mapping one and compute corresponding pfn
* values.
*/
pmd = pmdp_get_lockless(pmdp);
if (!pmd_devmap(pmd) && !pmd_trans_huge(pmd))
goto again;
return hmm_vma_handle_pmd(walk, addr, end, hmm_pfns, pmd);
}
/*
* We have handled all the valid cases above ie either none, migration,
* huge or transparent huge. At this point either it is a valid pmd
* entry pointing to pte directory or it is a bad pmd that will not
* recover.
*/
if (pmd_bad(pmd)) {
if (hmm_range_need_fault(hmm_vma_walk, hmm_pfns, npages, 0))
return -EFAULT;
return hmm_pfns_fill(start, end, range, HMM_PFN_ERROR);
}
ptep = pte_offset_map(pmdp, addr);
if (!ptep)
goto again;
for (; addr < end; addr += PAGE_SIZE, ptep++, hmm_pfns++) {
int r;
r = hmm_vma_handle_pte(walk, addr, end, pmdp, ptep, hmm_pfns);
if (r) {
/* hmm_vma_handle_pte() did pte_unmap() */
return r;
}
}
pte_unmap(ptep - 1);
return 0;
}
#if defined(CONFIG_ARCH_HAS_PTE_DEVMAP) && \
defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)
static inline unsigned long pud_to_hmm_pfn_flags(struct hmm_range *range,
pud_t pud)
{
if (!pud_present(pud))
return 0;
return (pud_write(pud) ? (HMM_PFN_VALID | HMM_PFN_WRITE) :
HMM_PFN_VALID) |
hmm_pfn_flags_order(PUD_SHIFT - PAGE_SHIFT);
}
static int hmm_vma_walk_pud(pud_t *pudp, unsigned long start, unsigned long end,
struct mm_walk *walk)
{
struct hmm_vma_walk *hmm_vma_walk = walk->private;
struct hmm_range *range = hmm_vma_walk->range;
unsigned long addr = start;
pud_t pud;
spinlock_t *ptl = pud_trans_huge_lock(pudp, walk->vma);
if (!ptl)
return 0;
/* Normally we don't want to split the huge page */
walk->action = ACTION_CONTINUE;
pud = READ_ONCE(*pudp);
if (pud_none(pud)) {
spin_unlock(ptl);
return hmm_vma_walk_hole(start, end, -1, walk);
}
if (pud_huge(pud) && pud_devmap(pud)) {
unsigned long i, npages, pfn;
unsigned int required_fault;
unsigned long *hmm_pfns;
unsigned long cpu_flags;
if (!pud_present(pud)) {
spin_unlock(ptl);
return hmm_vma_walk_hole(start, end, -1, walk);
}
i = (addr - range->start) >> PAGE_SHIFT;
npages = (end - addr) >> PAGE_SHIFT;
hmm_pfns = &range->hmm_pfns[i];
cpu_flags = pud_to_hmm_pfn_flags(range, pud);
required_fault = hmm_range_need_fault(hmm_vma_walk, hmm_pfns,
npages, cpu_flags);
if (required_fault) {
spin_unlock(ptl);
return hmm_vma_fault(addr, end, required_fault, walk);
}
pfn = pud_pfn(pud) + ((addr & ~PUD_MASK) >> PAGE_SHIFT);
for (i = 0; i < npages; ++i, ++pfn)
hmm_pfns[i] = pfn | cpu_flags;
goto out_unlock;
}
/* Ask for the PUD to be split */
walk->action = ACTION_SUBTREE;
out_unlock:
spin_unlock(ptl);
return 0;
}
#else
#define hmm_vma_walk_pud NULL
#endif
#ifdef CONFIG_HUGETLB_PAGE
static int hmm_vma_walk_hugetlb_entry(pte_t *pte, unsigned long hmask,
unsigned long start, unsigned long end,
struct mm_walk *walk)
{
unsigned long addr = start, i, pfn;
struct hmm_vma_walk *hmm_vma_walk = walk->private;
struct hmm_range *range = hmm_vma_walk->range;
struct vm_area_struct *vma = walk->vma;
unsigned int required_fault;
unsigned long pfn_req_flags;
unsigned long cpu_flags;
spinlock_t *ptl;
pte_t entry;
ptl = huge_pte_lock(hstate_vma(vma), walk->mm, pte);
entry = huge_ptep_get(pte);
i = (start - range->start) >> PAGE_SHIFT;
pfn_req_flags = range->hmm_pfns[i];
cpu_flags = pte_to_hmm_pfn_flags(range, entry) |
hmm_pfn_flags_order(huge_page_order(hstate_vma(vma)));
required_fault =
hmm_pte_need_fault(hmm_vma_walk, pfn_req_flags, cpu_flags);
if (required_fault) {
int ret;
spin_unlock(ptl);
hugetlb_vma_unlock_read(vma);
/*
* Avoid deadlock: drop the vma lock before calling
* hmm_vma_fault(), which will itself potentially take and
* drop the vma lock. This is also correct from a
* protection point of view, because there is no further
* use here of either pte or ptl after dropping the vma
* lock.
*/
ret = hmm_vma_fault(addr, end, required_fault, walk);
hugetlb_vma_lock_read(vma);
return ret;
}
pfn = pte_pfn(entry) + ((start & ~hmask) >> PAGE_SHIFT);
for (; addr < end; addr += PAGE_SIZE, i++, pfn++)
range->hmm_pfns[i] = pfn | cpu_flags;
spin_unlock(ptl);
return 0;
}
#else
#define hmm_vma_walk_hugetlb_entry NULL
#endif /* CONFIG_HUGETLB_PAGE */
static int hmm_vma_walk_test(unsigned long start, unsigned long end,
struct mm_walk *walk)
{
struct hmm_vma_walk *hmm_vma_walk = walk->private;
struct hmm_range *range = hmm_vma_walk->range;
struct vm_area_struct *vma = walk->vma;
if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)) &&
vma->vm_flags & VM_READ)
return 0;
/*
* vma ranges that don't have struct page backing them or map I/O
* devices directly cannot be handled by hmm_range_fault().
*
* If the vma does not allow read access, then assume that it does not
* allow write access either. HMM does not support architectures that
* allow write without read.
*
* If a fault is requested for an unsupported range then it is a hard
* failure.
*/
if (hmm_range_need_fault(hmm_vma_walk,
range->hmm_pfns +
((start - range->start) >> PAGE_SHIFT),
(end - start) >> PAGE_SHIFT, 0))
return -EFAULT;
hmm_pfns_fill(start, end, range, HMM_PFN_ERROR);
/* Skip this vma and continue processing the next vma. */
return 1;
}
static const struct mm_walk_ops hmm_walk_ops = {
.pud_entry = hmm_vma_walk_pud,
.pmd_entry = hmm_vma_walk_pmd,
.pte_hole = hmm_vma_walk_hole,
.hugetlb_entry = hmm_vma_walk_hugetlb_entry,
.test_walk = hmm_vma_walk_test,
.walk_lock = PGWALK_RDLOCK,
};
/**
* hmm_range_fault - try to fault some address in a virtual address range
* @range: argument structure
*
* Returns 0 on success or one of the following error codes:
*
* -EINVAL: Invalid arguments or mm or virtual address is in an invalid vma
* (e.g., device file vma).
* -ENOMEM: Out of memory.
* -EPERM: Invalid permission (e.g., asking for write and range is read
* only).
* -EBUSY: The range has been invalidated and the caller needs to wait for
* the invalidation to finish.
* -EFAULT: A page was requested to be valid and could not be made valid
* ie it has no backing VMA or it is illegal to access
*
* This is similar to get_user_pages(), except that it can read the page tables
* without mutating them (ie causing faults).
*/
int hmm_range_fault(struct hmm_range *range)
{
struct hmm_vma_walk hmm_vma_walk = {
.range = range,
.last = range->start,
};
struct mm_struct *mm = range->notifier->mm;
int ret;
mmap_assert_locked(mm);
do {
/* If range is no longer valid force retry. */
if (mmu_interval_check_retry(range->notifier,
range->notifier_seq))
return -EBUSY;
ret = walk_page_range(mm, hmm_vma_walk.last, range->end,
&hmm_walk_ops, &hmm_vma_walk);
/*
* When -EBUSY is returned the loop restarts with
* hmm_vma_walk.last set to an address that has not been stored
* in pfns. All entries < last in the pfn array are set to their
* output, and all >= are still at their input values.
*/
} while (ret == -EBUSY);
return ret;
}
EXPORT_SYMBOL(hmm_range_fault);
| linux-master | mm/hmm.c |
// SPDX-License-Identifier: GPL-2.0
/*
* linux/mm/swap_state.c
*
* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
* Swap reorganised 29.12.95, Stephen Tweedie
*
* Rewritten to use page cache, (C) 1998 Stephen Tweedie
*/
#include <linux/mm.h>
#include <linux/gfp.h>
#include <linux/kernel_stat.h>
#include <linux/swap.h>
#include <linux/swapops.h>
#include <linux/init.h>
#include <linux/pagemap.h>
#include <linux/backing-dev.h>
#include <linux/blkdev.h>
#include <linux/migrate.h>
#include <linux/vmalloc.h>
#include <linux/swap_slots.h>
#include <linux/huge_mm.h>
#include <linux/shmem_fs.h>
#include "internal.h"
#include "swap.h"
/*
* swapper_space is a fiction, retained to simplify the path through
* vmscan's shrink_page_list.
*/
static const struct address_space_operations swap_aops = {
.writepage = swap_writepage,
.dirty_folio = noop_dirty_folio,
#ifdef CONFIG_MIGRATION
.migrate_folio = migrate_folio,
#endif
};
struct address_space *swapper_spaces[MAX_SWAPFILES] __read_mostly;
static unsigned int nr_swapper_spaces[MAX_SWAPFILES] __read_mostly;
static bool enable_vma_readahead __read_mostly = true;
#define SWAP_RA_WIN_SHIFT (PAGE_SHIFT / 2)
#define SWAP_RA_HITS_MASK ((1UL << SWAP_RA_WIN_SHIFT) - 1)
#define SWAP_RA_HITS_MAX SWAP_RA_HITS_MASK
#define SWAP_RA_WIN_MASK (~PAGE_MASK & ~SWAP_RA_HITS_MASK)
#define SWAP_RA_HITS(v) ((v) & SWAP_RA_HITS_MASK)
#define SWAP_RA_WIN(v) (((v) & SWAP_RA_WIN_MASK) >> SWAP_RA_WIN_SHIFT)
#define SWAP_RA_ADDR(v) ((v) & PAGE_MASK)
#define SWAP_RA_VAL(addr, win, hits) \
(((addr) & PAGE_MASK) | \
(((win) << SWAP_RA_WIN_SHIFT) & SWAP_RA_WIN_MASK) | \
((hits) & SWAP_RA_HITS_MASK))
/* Initial readahead hits is 4 to start up with a small window */
#define GET_SWAP_RA_VAL(vma) \
(atomic_long_read(&(vma)->swap_readahead_info) ? : 4)
static atomic_t swapin_readahead_hits = ATOMIC_INIT(4);
void show_swap_cache_info(void)
{
printk("%lu pages in swap cache\n", total_swapcache_pages());
printk("Free swap = %ldkB\n", K(get_nr_swap_pages()));
printk("Total swap = %lukB\n", K(total_swap_pages));
}
void *get_shadow_from_swap_cache(swp_entry_t entry)
{
struct address_space *address_space = swap_address_space(entry);
pgoff_t idx = swp_offset(entry);
struct page *page;
page = xa_load(&address_space->i_pages, idx);
if (xa_is_value(page))
return page;
return NULL;
}
/*
* add_to_swap_cache resembles filemap_add_folio on swapper_space,
* but sets SwapCache flag and private instead of mapping and index.
*/
int add_to_swap_cache(struct folio *folio, swp_entry_t entry,
gfp_t gfp, void **shadowp)
{
struct address_space *address_space = swap_address_space(entry);
pgoff_t idx = swp_offset(entry);
XA_STATE_ORDER(xas, &address_space->i_pages, idx, folio_order(folio));
unsigned long i, nr = folio_nr_pages(folio);
void *old;
xas_set_update(&xas, workingset_update_node);
VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);
VM_BUG_ON_FOLIO(folio_test_swapcache(folio), folio);
VM_BUG_ON_FOLIO(!folio_test_swapbacked(folio), folio);
folio_ref_add(folio, nr);
folio_set_swapcache(folio);
folio->swap = entry;
do {
xas_lock_irq(&xas);
xas_create_range(&xas);
if (xas_error(&xas))
goto unlock;
for (i = 0; i < nr; i++) {
VM_BUG_ON_FOLIO(xas.xa_index != idx + i, folio);
old = xas_load(&xas);
if (xa_is_value(old)) {
if (shadowp)
*shadowp = old;
}
xas_store(&xas, folio);
xas_next(&xas);
}
address_space->nrpages += nr;
__node_stat_mod_folio(folio, NR_FILE_PAGES, nr);
__lruvec_stat_mod_folio(folio, NR_SWAPCACHE, nr);
unlock:
xas_unlock_irq(&xas);
} while (xas_nomem(&xas, gfp));
if (!xas_error(&xas))
return 0;
folio_clear_swapcache(folio);
folio_ref_sub(folio, nr);
return xas_error(&xas);
}
/*
* This must be called only on folios that have
* been verified to be in the swap cache.
*/
void __delete_from_swap_cache(struct folio *folio,
swp_entry_t entry, void *shadow)
{
struct address_space *address_space = swap_address_space(entry);
int i;
long nr = folio_nr_pages(folio);
pgoff_t idx = swp_offset(entry);
XA_STATE(xas, &address_space->i_pages, idx);
xas_set_update(&xas, workingset_update_node);
VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);
VM_BUG_ON_FOLIO(!folio_test_swapcache(folio), folio);
VM_BUG_ON_FOLIO(folio_test_writeback(folio), folio);
for (i = 0; i < nr; i++) {
void *entry = xas_store(&xas, shadow);
VM_BUG_ON_PAGE(entry != folio, entry);
xas_next(&xas);
}
folio->swap.val = 0;
folio_clear_swapcache(folio);
address_space->nrpages -= nr;
__node_stat_mod_folio(folio, NR_FILE_PAGES, -nr);
__lruvec_stat_mod_folio(folio, NR_SWAPCACHE, -nr);
}
/**
* add_to_swap - allocate swap space for a folio
* @folio: folio we want to move to swap
*
* Allocate swap space for the folio and add the folio to the
* swap cache.
*
* Context: Caller needs to hold the folio lock.
* Return: Whether the folio was added to the swap cache.
*/
bool add_to_swap(struct folio *folio)
{
swp_entry_t entry;
int err;
VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);
VM_BUG_ON_FOLIO(!folio_test_uptodate(folio), folio);
entry = folio_alloc_swap(folio);
if (!entry.val)
return false;
/*
* XArray node allocations from PF_MEMALLOC contexts could
* completely exhaust the page allocator. __GFP_NOMEMALLOC
* stops emergency reserves from being allocated.
*
* TODO: this could cause a theoretical memory reclaim
* deadlock in the swap out path.
*/
/*
* Add it to the swap cache.
*/
err = add_to_swap_cache(folio, entry,
__GFP_HIGH|__GFP_NOMEMALLOC|__GFP_NOWARN, NULL);
if (err)
/*
* add_to_swap_cache() doesn't return -EEXIST, so we can safely
* clear SWAP_HAS_CACHE flag.
*/
goto fail;
/*
* Normally the folio will be dirtied in unmap because its
* pte should be dirty. A special case is MADV_FREE page. The
* page's pte could have dirty bit cleared but the folio's
* SwapBacked flag is still set because clearing the dirty bit
* and SwapBacked flag has no lock protected. For such folio,
* unmap will not set dirty bit for it, so folio reclaim will
* not write the folio out. This can cause data corruption when
* the folio is swapped in later. Always setting the dirty flag
* for the folio solves the problem.
*/
folio_mark_dirty(folio);
return true;
fail:
put_swap_folio(folio, entry);
return false;
}
/*
* This must be called only on folios that have
* been verified to be in the swap cache and locked.
* It will never put the folio into the free list,
* the caller has a reference on the folio.
*/
void delete_from_swap_cache(struct folio *folio)
{
swp_entry_t entry = folio->swap;
struct address_space *address_space = swap_address_space(entry);
xa_lock_irq(&address_space->i_pages);
__delete_from_swap_cache(folio, entry, NULL);
xa_unlock_irq(&address_space->i_pages);
put_swap_folio(folio, entry);
folio_ref_sub(folio, folio_nr_pages(folio));
}
void clear_shadow_from_swap_cache(int type, unsigned long begin,
unsigned long end)
{
unsigned long curr = begin;
void *old;
for (;;) {
swp_entry_t entry = swp_entry(type, curr);
struct address_space *address_space = swap_address_space(entry);
XA_STATE(xas, &address_space->i_pages, curr);
xas_set_update(&xas, workingset_update_node);
xa_lock_irq(&address_space->i_pages);
xas_for_each(&xas, old, end) {
if (!xa_is_value(old))
continue;
xas_store(&xas, NULL);
}
xa_unlock_irq(&address_space->i_pages);
/* search the next swapcache until we meet end */
curr >>= SWAP_ADDRESS_SPACE_SHIFT;
curr++;
curr <<= SWAP_ADDRESS_SPACE_SHIFT;
if (curr > end)
break;
}
}
/*
* If we are the only user, then try to free up the swap cache.
*
* Its ok to check the swapcache flag without the folio lock
* here because we are going to recheck again inside
* folio_free_swap() _with_ the lock.
* - Marcelo
*/
void free_swap_cache(struct page *page)
{
struct folio *folio = page_folio(page);
if (folio_test_swapcache(folio) && !folio_mapped(folio) &&
folio_trylock(folio)) {
folio_free_swap(folio);
folio_unlock(folio);
}
}
/*
* Perform a free_page(), also freeing any swap cache associated with
* this page if it is the last user of the page.
*/
void free_page_and_swap_cache(struct page *page)
{
free_swap_cache(page);
if (!is_huge_zero_page(page))
put_page(page);
}
/*
* Passed an array of pages, drop them all from swapcache and then release
* them. They are removed from the LRU and freed if this is their last use.
*/
void free_pages_and_swap_cache(struct encoded_page **pages, int nr)
{
lru_add_drain();
for (int i = 0; i < nr; i++)
free_swap_cache(encoded_page_ptr(pages[i]));
release_pages(pages, nr);
}
static inline bool swap_use_vma_readahead(void)
{
return READ_ONCE(enable_vma_readahead) && !atomic_read(&nr_rotate_swap);
}
/*
* Lookup a swap entry in the swap cache. A found folio will be returned
* unlocked and with its refcount incremented - we rely on the kernel
* lock getting page table operations atomic even if we drop the folio
* lock before returning.
*
* Caller must lock the swap device or hold a reference to keep it valid.
*/
struct folio *swap_cache_get_folio(swp_entry_t entry,
struct vm_area_struct *vma, unsigned long addr)
{
struct folio *folio;
folio = filemap_get_folio(swap_address_space(entry), swp_offset(entry));
if (!IS_ERR(folio)) {
bool vma_ra = swap_use_vma_readahead();
bool readahead;
/*
* At the moment, we don't support PG_readahead for anon THP
* so let's bail out rather than confusing the readahead stat.
*/
if (unlikely(folio_test_large(folio)))
return folio;
readahead = folio_test_clear_readahead(folio);
if (vma && vma_ra) {
unsigned long ra_val;
int win, hits;
ra_val = GET_SWAP_RA_VAL(vma);
win = SWAP_RA_WIN(ra_val);
hits = SWAP_RA_HITS(ra_val);
if (readahead)
hits = min_t(int, hits + 1, SWAP_RA_HITS_MAX);
atomic_long_set(&vma->swap_readahead_info,
SWAP_RA_VAL(addr, win, hits));
}
if (readahead) {
count_vm_event(SWAP_RA_HIT);
if (!vma || !vma_ra)
atomic_inc(&swapin_readahead_hits);
}
} else {
folio = NULL;
}
return folio;
}
/**
* filemap_get_incore_folio - Find and get a folio from the page or swap caches.
* @mapping: The address_space to search.
* @index: The page cache index.
*
* This differs from filemap_get_folio() in that it will also look for the
* folio in the swap cache.
*
* Return: The found folio or %NULL.
*/
struct folio *filemap_get_incore_folio(struct address_space *mapping,
pgoff_t index)
{
swp_entry_t swp;
struct swap_info_struct *si;
struct folio *folio = filemap_get_entry(mapping, index);
if (!folio)
return ERR_PTR(-ENOENT);
if (!xa_is_value(folio))
return folio;
if (!shmem_mapping(mapping))
return ERR_PTR(-ENOENT);
swp = radix_to_swp_entry(folio);
/* There might be swapin error entries in shmem mapping. */
if (non_swap_entry(swp))
return ERR_PTR(-ENOENT);
/* Prevent swapoff from happening to us */
si = get_swap_device(swp);
if (!si)
return ERR_PTR(-ENOENT);
index = swp_offset(swp);
folio = filemap_get_folio(swap_address_space(swp), index);
put_swap_device(si);
return folio;
}
struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
struct vm_area_struct *vma, unsigned long addr,
bool *new_page_allocated)
{
struct swap_info_struct *si;
struct folio *folio;
struct page *page;
void *shadow = NULL;
*new_page_allocated = false;
si = get_swap_device(entry);
if (!si)
return NULL;
for (;;) {
int err;
/*
* First check the swap cache. Since this is normally
* called after swap_cache_get_folio() failed, re-calling
* that would confuse statistics.
*/
folio = filemap_get_folio(swap_address_space(entry),
swp_offset(entry));
if (!IS_ERR(folio)) {
page = folio_file_page(folio, swp_offset(entry));
goto got_page;
}
/*
* Just skip read ahead for unused swap slot.
* During swap_off when swap_slot_cache is disabled,
* we have to handle the race between putting
* swap entry in swap cache and marking swap slot
* as SWAP_HAS_CACHE. That's done in later part of code or
* else swap_off will be aborted if we return NULL.
*/
if (!swap_swapcount(si, entry) && swap_slot_cache_enabled)
goto fail_put_swap;
/*
* Get a new page to read into from swap. Allocate it now,
* before marking swap_map SWAP_HAS_CACHE, when -EEXIST will
* cause any racers to loop around until we add it to cache.
*/
folio = vma_alloc_folio(gfp_mask, 0, vma, addr, false);
if (!folio)
goto fail_put_swap;
/*
* Swap entry may have been freed since our caller observed it.
*/
err = swapcache_prepare(entry);
if (!err)
break;
folio_put(folio);
if (err != -EEXIST)
goto fail_put_swap;
/*
* We might race against __delete_from_swap_cache(), and
* stumble across a swap_map entry whose SWAP_HAS_CACHE
* has not yet been cleared. Or race against another
* __read_swap_cache_async(), which has set SWAP_HAS_CACHE
* in swap_map, but not yet added its page to swap cache.
*/
schedule_timeout_uninterruptible(1);
}
/*
* The swap entry is ours to swap in. Prepare the new page.
*/
__folio_set_locked(folio);
__folio_set_swapbacked(folio);
if (mem_cgroup_swapin_charge_folio(folio, NULL, gfp_mask, entry))
goto fail_unlock;
/* May fail (-ENOMEM) if XArray node allocation failed. */
if (add_to_swap_cache(folio, entry, gfp_mask & GFP_RECLAIM_MASK, &shadow))
goto fail_unlock;
mem_cgroup_swapin_uncharge_swap(entry);
if (shadow)
workingset_refault(folio, shadow);
/* Caller will initiate read into locked folio */
folio_add_lru(folio);
*new_page_allocated = true;
page = &folio->page;
got_page:
put_swap_device(si);
return page;
fail_unlock:
put_swap_folio(folio, entry);
folio_unlock(folio);
folio_put(folio);
fail_put_swap:
put_swap_device(si);
return NULL;
}
/*
* Locate a page of swap in physical memory, reserving swap cache space
* and reading the disk if it is not already cached.
* A failure return means that either the page allocation failed or that
* the swap entry is no longer in use.
*
* get/put_swap_device() aren't needed to call this function, because
* __read_swap_cache_async() call them and swap_readpage() holds the
* swap cache folio lock.
*/
struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
struct vm_area_struct *vma,
unsigned long addr, struct swap_iocb **plug)
{
bool page_was_allocated;
struct page *retpage = __read_swap_cache_async(entry, gfp_mask,
vma, addr, &page_was_allocated);
if (page_was_allocated)
swap_readpage(retpage, false, plug);
return retpage;
}
static unsigned int __swapin_nr_pages(unsigned long prev_offset,
unsigned long offset,
int hits,
int max_pages,
int prev_win)
{
unsigned int pages, last_ra;
/*
* This heuristic has been found to work well on both sequential and
* random loads, swapping to hard disk or to SSD: please don't ask
* what the "+ 2" means, it just happens to work well, that's all.
*/
pages = hits + 2;
if (pages == 2) {
/*
* We can have no readahead hits to judge by: but must not get
* stuck here forever, so check for an adjacent offset instead
* (and don't even bother to check whether swap type is same).
*/
if (offset != prev_offset + 1 && offset != prev_offset - 1)
pages = 1;
} else {
unsigned int roundup = 4;
while (roundup < pages)
roundup <<= 1;
pages = roundup;
}
if (pages > max_pages)
pages = max_pages;
/* Don't shrink readahead too fast */
last_ra = prev_win / 2;
if (pages < last_ra)
pages = last_ra;
return pages;
}
static unsigned long swapin_nr_pages(unsigned long offset)
{
static unsigned long prev_offset;
unsigned int hits, pages, max_pages;
static atomic_t last_readahead_pages;
max_pages = 1 << READ_ONCE(page_cluster);
if (max_pages <= 1)
return 1;
hits = atomic_xchg(&swapin_readahead_hits, 0);
pages = __swapin_nr_pages(READ_ONCE(prev_offset), offset, hits,
max_pages,
atomic_read(&last_readahead_pages));
if (!hits)
WRITE_ONCE(prev_offset, offset);
atomic_set(&last_readahead_pages, pages);
return pages;
}
/**
* swap_cluster_readahead - swap in pages in hope we need them soon
* @entry: swap entry of this memory
* @gfp_mask: memory allocation flags
* @vmf: fault information
*
* Returns the struct page for entry and addr, after queueing swapin.
*
* Primitive swap readahead code. We simply read an aligned block of
* (1 << page_cluster) entries in the swap area. This method is chosen
* because it doesn't cost us any seek time. We also make sure to queue
* the 'original' request together with the readahead ones...
*
* This has been extended to use the NUMA policies from the mm triggering
* the readahead.
*
* Caller must hold read mmap_lock if vmf->vma is not NULL.
*/
struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t gfp_mask,
struct vm_fault *vmf)
{
struct page *page;
unsigned long entry_offset = swp_offset(entry);
unsigned long offset = entry_offset;
unsigned long start_offset, end_offset;
unsigned long mask;
struct swap_info_struct *si = swp_swap_info(entry);
struct blk_plug plug;
struct swap_iocb *splug = NULL;
bool page_allocated;
struct vm_area_struct *vma = vmf->vma;
unsigned long addr = vmf->address;
mask = swapin_nr_pages(offset) - 1;
if (!mask)
goto skip;
/* Read a page_cluster sized and aligned cluster around offset. */
start_offset = offset & ~mask;
end_offset = offset | mask;
if (!start_offset) /* First page is swap header. */
start_offset++;
if (end_offset >= si->max)
end_offset = si->max - 1;
blk_start_plug(&plug);
for (offset = start_offset; offset <= end_offset ; offset++) {
/* Ok, do the async read-ahead now */
page = __read_swap_cache_async(
swp_entry(swp_type(entry), offset),
gfp_mask, vma, addr, &page_allocated);
if (!page)
continue;
if (page_allocated) {
swap_readpage(page, false, &splug);
if (offset != entry_offset) {
SetPageReadahead(page);
count_vm_event(SWAP_RA);
}
}
put_page(page);
}
blk_finish_plug(&plug);
swap_read_unplug(splug);
lru_add_drain(); /* Push any new pages onto the LRU now */
skip:
/* The page was likely read above, so no need for plugging here */
return read_swap_cache_async(entry, gfp_mask, vma, addr, NULL);
}
int init_swap_address_space(unsigned int type, unsigned long nr_pages)
{
struct address_space *spaces, *space;
unsigned int i, nr;
nr = DIV_ROUND_UP(nr_pages, SWAP_ADDRESS_SPACE_PAGES);
spaces = kvcalloc(nr, sizeof(struct address_space), GFP_KERNEL);
if (!spaces)
return -ENOMEM;
for (i = 0; i < nr; i++) {
space = spaces + i;
xa_init_flags(&space->i_pages, XA_FLAGS_LOCK_IRQ);
atomic_set(&space->i_mmap_writable, 0);
space->a_ops = &swap_aops;
/* swap cache doesn't use writeback related tags */
mapping_set_no_writeback_tags(space);
}
nr_swapper_spaces[type] = nr;
swapper_spaces[type] = spaces;
return 0;
}
void exit_swap_address_space(unsigned int type)
{
int i;
struct address_space *spaces = swapper_spaces[type];
for (i = 0; i < nr_swapper_spaces[type]; i++)
VM_WARN_ON_ONCE(!mapping_empty(&spaces[i]));
kvfree(spaces);
nr_swapper_spaces[type] = 0;
swapper_spaces[type] = NULL;
}
#define SWAP_RA_ORDER_CEILING 5
struct vma_swap_readahead {
unsigned short win;
unsigned short offset;
unsigned short nr_pte;
};
static void swap_ra_info(struct vm_fault *vmf,
struct vma_swap_readahead *ra_info)
{
struct vm_area_struct *vma = vmf->vma;
unsigned long ra_val;
unsigned long faddr, pfn, fpfn, lpfn, rpfn;
unsigned long start, end;
unsigned int max_win, hits, prev_win, win;
max_win = 1 << min_t(unsigned int, READ_ONCE(page_cluster),
SWAP_RA_ORDER_CEILING);
if (max_win == 1) {
ra_info->win = 1;
return;
}
faddr = vmf->address;
fpfn = PFN_DOWN(faddr);
ra_val = GET_SWAP_RA_VAL(vma);
pfn = PFN_DOWN(SWAP_RA_ADDR(ra_val));
prev_win = SWAP_RA_WIN(ra_val);
hits = SWAP_RA_HITS(ra_val);
ra_info->win = win = __swapin_nr_pages(pfn, fpfn, hits,
max_win, prev_win);
atomic_long_set(&vma->swap_readahead_info,
SWAP_RA_VAL(faddr, win, 0));
if (win == 1)
return;
if (fpfn == pfn + 1) {
lpfn = fpfn;
rpfn = fpfn + win;
} else if (pfn == fpfn + 1) {
lpfn = fpfn - win + 1;
rpfn = fpfn + 1;
} else {
unsigned int left = (win - 1) / 2;
lpfn = fpfn - left;
rpfn = fpfn + win - left;
}
start = max3(lpfn, PFN_DOWN(vma->vm_start),
PFN_DOWN(faddr & PMD_MASK));
end = min3(rpfn, PFN_DOWN(vma->vm_end),
PFN_DOWN((faddr & PMD_MASK) + PMD_SIZE));
ra_info->nr_pte = end - start;
ra_info->offset = fpfn - start;
}
/**
* swap_vma_readahead - swap in pages in hope we need them soon
* @fentry: swap entry of this memory
* @gfp_mask: memory allocation flags
* @vmf: fault information
*
* Returns the struct page for entry and addr, after queueing swapin.
*
* Primitive swap readahead code. We simply read in a few pages whose
* virtual addresses are around the fault address in the same vma.
*
* Caller must hold read mmap_lock if vmf->vma is not NULL.
*
*/
static struct page *swap_vma_readahead(swp_entry_t fentry, gfp_t gfp_mask,
struct vm_fault *vmf)
{
struct blk_plug plug;
struct swap_iocb *splug = NULL;
struct vm_area_struct *vma = vmf->vma;
struct page *page;
pte_t *pte = NULL, pentry;
unsigned long addr;
swp_entry_t entry;
unsigned int i;
bool page_allocated;
struct vma_swap_readahead ra_info = {
.win = 1,
};
swap_ra_info(vmf, &ra_info);
if (ra_info.win == 1)
goto skip;
addr = vmf->address - (ra_info.offset * PAGE_SIZE);
blk_start_plug(&plug);
for (i = 0; i < ra_info.nr_pte; i++, addr += PAGE_SIZE) {
if (!pte++) {
pte = pte_offset_map(vmf->pmd, addr);
if (!pte)
break;
}
pentry = ptep_get_lockless(pte);
if (!is_swap_pte(pentry))
continue;
entry = pte_to_swp_entry(pentry);
if (unlikely(non_swap_entry(entry)))
continue;
pte_unmap(pte);
pte = NULL;
page = __read_swap_cache_async(entry, gfp_mask, vma,
addr, &page_allocated);
if (!page)
continue;
if (page_allocated) {
swap_readpage(page, false, &splug);
if (i != ra_info.offset) {
SetPageReadahead(page);
count_vm_event(SWAP_RA);
}
}
put_page(page);
}
if (pte)
pte_unmap(pte);
blk_finish_plug(&plug);
swap_read_unplug(splug);
lru_add_drain();
skip:
/* The page was likely read above, so no need for plugging here */
return read_swap_cache_async(fentry, gfp_mask, vma, vmf->address,
NULL);
}
/**
* swapin_readahead - swap in pages in hope we need them soon
* @entry: swap entry of this memory
* @gfp_mask: memory allocation flags
* @vmf: fault information
*
* Returns the struct page for entry and addr, after queueing swapin.
*
* It's a main entry function for swap readahead. By the configuration,
* it will read ahead blocks by cluster-based(ie, physical disk based)
* or vma-based(ie, virtual address based on faulty address) readahead.
*/
struct page *swapin_readahead(swp_entry_t entry, gfp_t gfp_mask,
struct vm_fault *vmf)
{
return swap_use_vma_readahead() ?
swap_vma_readahead(entry, gfp_mask, vmf) :
swap_cluster_readahead(entry, gfp_mask, vmf);
}
#ifdef CONFIG_SYSFS
static ssize_t vma_ra_enabled_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
return sysfs_emit(buf, "%s\n",
enable_vma_readahead ? "true" : "false");
}
static ssize_t vma_ra_enabled_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
{
ssize_t ret;
ret = kstrtobool(buf, &enable_vma_readahead);
if (ret)
return ret;
return count;
}
static struct kobj_attribute vma_ra_enabled_attr = __ATTR_RW(vma_ra_enabled);
static struct attribute *swap_attrs[] = {
&vma_ra_enabled_attr.attr,
NULL,
};
static const struct attribute_group swap_attr_group = {
.attrs = swap_attrs,
};
static int __init swap_init_sysfs(void)
{
int err;
struct kobject *swap_kobj;
swap_kobj = kobject_create_and_add("swap", mm_kobj);
if (!swap_kobj) {
pr_err("failed to create swap kobject\n");
return -ENOMEM;
}
err = sysfs_create_group(swap_kobj, &swap_attr_group);
if (err) {
pr_err("failed to register swap group\n");
goto delete_obj;
}
return 0;
delete_obj:
kobject_put(swap_kobj);
return err;
}
subsys_initcall(swap_init_sysfs);
#endif
| linux-master | mm/swap_state.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* Generic show_mem() implementation
*
* Copyright (C) 2008 Johannes Weiner <[email protected]>
*/
#include <linux/blkdev.h>
#include <linux/cma.h>
#include <linux/cpuset.h>
#include <linux/highmem.h>
#include <linux/hugetlb.h>
#include <linux/mm.h>
#include <linux/mmzone.h>
#include <linux/swap.h>
#include <linux/vmstat.h>
#include "internal.h"
#include "swap.h"
atomic_long_t _totalram_pages __read_mostly;
EXPORT_SYMBOL(_totalram_pages);
unsigned long totalreserve_pages __read_mostly;
unsigned long totalcma_pages __read_mostly;
static inline void show_node(struct zone *zone)
{
if (IS_ENABLED(CONFIG_NUMA))
printk("Node %d ", zone_to_nid(zone));
}
long si_mem_available(void)
{
long available;
unsigned long pagecache;
unsigned long wmark_low = 0;
unsigned long pages[NR_LRU_LISTS];
unsigned long reclaimable;
struct zone *zone;
int lru;
for (lru = LRU_BASE; lru < NR_LRU_LISTS; lru++)
pages[lru] = global_node_page_state(NR_LRU_BASE + lru);
for_each_zone(zone)
wmark_low += low_wmark_pages(zone);
/*
* Estimate the amount of memory available for userspace allocations,
* without causing swapping or OOM.
*/
available = global_zone_page_state(NR_FREE_PAGES) - totalreserve_pages;
/*
* Not all the page cache can be freed, otherwise the system will
* start swapping or thrashing. Assume at least half of the page
* cache, or the low watermark worth of cache, needs to stay.
*/
pagecache = pages[LRU_ACTIVE_FILE] + pages[LRU_INACTIVE_FILE];
pagecache -= min(pagecache / 2, wmark_low);
available += pagecache;
/*
* Part of the reclaimable slab and other kernel memory consists of
* items that are in use, and cannot be freed. Cap this estimate at the
* low watermark.
*/
reclaimable = global_node_page_state_pages(NR_SLAB_RECLAIMABLE_B) +
global_node_page_state(NR_KERNEL_MISC_RECLAIMABLE);
available += reclaimable - min(reclaimable / 2, wmark_low);
if (available < 0)
available = 0;
return available;
}
EXPORT_SYMBOL_GPL(si_mem_available);
void si_meminfo(struct sysinfo *val)
{
val->totalram = totalram_pages();
val->sharedram = global_node_page_state(NR_SHMEM);
val->freeram = global_zone_page_state(NR_FREE_PAGES);
val->bufferram = nr_blockdev_pages();
val->totalhigh = totalhigh_pages();
val->freehigh = nr_free_highpages();
val->mem_unit = PAGE_SIZE;
}
EXPORT_SYMBOL(si_meminfo);
#ifdef CONFIG_NUMA
void si_meminfo_node(struct sysinfo *val, int nid)
{
int zone_type; /* needs to be signed */
unsigned long managed_pages = 0;
unsigned long managed_highpages = 0;
unsigned long free_highpages = 0;
pg_data_t *pgdat = NODE_DATA(nid);
for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++)
managed_pages += zone_managed_pages(&pgdat->node_zones[zone_type]);
val->totalram = managed_pages;
val->sharedram = node_page_state(pgdat, NR_SHMEM);
val->freeram = sum_zone_node_page_state(nid, NR_FREE_PAGES);
#ifdef CONFIG_HIGHMEM
for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
struct zone *zone = &pgdat->node_zones[zone_type];
if (is_highmem(zone)) {
managed_highpages += zone_managed_pages(zone);
free_highpages += zone_page_state(zone, NR_FREE_PAGES);
}
}
val->totalhigh = managed_highpages;
val->freehigh = free_highpages;
#else
val->totalhigh = managed_highpages;
val->freehigh = free_highpages;
#endif
val->mem_unit = PAGE_SIZE;
}
#endif
/*
* Determine whether the node should be displayed or not, depending on whether
* SHOW_MEM_FILTER_NODES was passed to show_free_areas().
*/
static bool show_mem_node_skip(unsigned int flags, int nid, nodemask_t *nodemask)
{
if (!(flags & SHOW_MEM_FILTER_NODES))
return false;
/*
* no node mask - aka implicit memory numa policy. Do not bother with
* the synchronization - read_mems_allowed_begin - because we do not
* have to be precise here.
*/
if (!nodemask)
nodemask = &cpuset_current_mems_allowed;
return !node_isset(nid, *nodemask);
}
static void show_migration_types(unsigned char type)
{
static const char types[MIGRATE_TYPES] = {
[MIGRATE_UNMOVABLE] = 'U',
[MIGRATE_MOVABLE] = 'M',
[MIGRATE_RECLAIMABLE] = 'E',
[MIGRATE_HIGHATOMIC] = 'H',
#ifdef CONFIG_CMA
[MIGRATE_CMA] = 'C',
#endif
#ifdef CONFIG_MEMORY_ISOLATION
[MIGRATE_ISOLATE] = 'I',
#endif
};
char tmp[MIGRATE_TYPES + 1];
char *p = tmp;
int i;
for (i = 0; i < MIGRATE_TYPES; i++) {
if (type & (1 << i))
*p++ = types[i];
}
*p = '\0';
printk(KERN_CONT "(%s) ", tmp);
}
static bool node_has_managed_zones(pg_data_t *pgdat, int max_zone_idx)
{
int zone_idx;
for (zone_idx = 0; zone_idx <= max_zone_idx; zone_idx++)
if (zone_managed_pages(pgdat->node_zones + zone_idx))
return true;
return false;
}
/*
* Show free area list (used inside shift_scroll-lock stuff)
* We also calculate the percentage fragmentation. We do this by counting the
* memory on each free list with the exception of the first item on the list.
*
* Bits in @filter:
* SHOW_MEM_FILTER_NODES: suppress nodes that are not allowed by current's
* cpuset.
*/
static void show_free_areas(unsigned int filter, nodemask_t *nodemask, int max_zone_idx)
{
unsigned long free_pcp = 0;
int cpu, nid;
struct zone *zone;
pg_data_t *pgdat;
for_each_populated_zone(zone) {
if (zone_idx(zone) > max_zone_idx)
continue;
if (show_mem_node_skip(filter, zone_to_nid(zone), nodemask))
continue;
for_each_online_cpu(cpu)
free_pcp += per_cpu_ptr(zone->per_cpu_pageset, cpu)->count;
}
printk("active_anon:%lu inactive_anon:%lu isolated_anon:%lu\n"
" active_file:%lu inactive_file:%lu isolated_file:%lu\n"
" unevictable:%lu dirty:%lu writeback:%lu\n"
" slab_reclaimable:%lu slab_unreclaimable:%lu\n"
" mapped:%lu shmem:%lu pagetables:%lu\n"
" sec_pagetables:%lu bounce:%lu\n"
" kernel_misc_reclaimable:%lu\n"
" free:%lu free_pcp:%lu free_cma:%lu\n",
global_node_page_state(NR_ACTIVE_ANON),
global_node_page_state(NR_INACTIVE_ANON),
global_node_page_state(NR_ISOLATED_ANON),
global_node_page_state(NR_ACTIVE_FILE),
global_node_page_state(NR_INACTIVE_FILE),
global_node_page_state(NR_ISOLATED_FILE),
global_node_page_state(NR_UNEVICTABLE),
global_node_page_state(NR_FILE_DIRTY),
global_node_page_state(NR_WRITEBACK),
global_node_page_state_pages(NR_SLAB_RECLAIMABLE_B),
global_node_page_state_pages(NR_SLAB_UNRECLAIMABLE_B),
global_node_page_state(NR_FILE_MAPPED),
global_node_page_state(NR_SHMEM),
global_node_page_state(NR_PAGETABLE),
global_node_page_state(NR_SECONDARY_PAGETABLE),
global_zone_page_state(NR_BOUNCE),
global_node_page_state(NR_KERNEL_MISC_RECLAIMABLE),
global_zone_page_state(NR_FREE_PAGES),
free_pcp,
global_zone_page_state(NR_FREE_CMA_PAGES));
for_each_online_pgdat(pgdat) {
if (show_mem_node_skip(filter, pgdat->node_id, nodemask))
continue;
if (!node_has_managed_zones(pgdat, max_zone_idx))
continue;
printk("Node %d"
" active_anon:%lukB"
" inactive_anon:%lukB"
" active_file:%lukB"
" inactive_file:%lukB"
" unevictable:%lukB"
" isolated(anon):%lukB"
" isolated(file):%lukB"
" mapped:%lukB"
" dirty:%lukB"
" writeback:%lukB"
" shmem:%lukB"
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
" shmem_thp:%lukB"
" shmem_pmdmapped:%lukB"
" anon_thp:%lukB"
#endif
" writeback_tmp:%lukB"
" kernel_stack:%lukB"
#ifdef CONFIG_SHADOW_CALL_STACK
" shadow_call_stack:%lukB"
#endif
" pagetables:%lukB"
" sec_pagetables:%lukB"
" all_unreclaimable? %s"
"\n",
pgdat->node_id,
K(node_page_state(pgdat, NR_ACTIVE_ANON)),
K(node_page_state(pgdat, NR_INACTIVE_ANON)),
K(node_page_state(pgdat, NR_ACTIVE_FILE)),
K(node_page_state(pgdat, NR_INACTIVE_FILE)),
K(node_page_state(pgdat, NR_UNEVICTABLE)),
K(node_page_state(pgdat, NR_ISOLATED_ANON)),
K(node_page_state(pgdat, NR_ISOLATED_FILE)),
K(node_page_state(pgdat, NR_FILE_MAPPED)),
K(node_page_state(pgdat, NR_FILE_DIRTY)),
K(node_page_state(pgdat, NR_WRITEBACK)),
K(node_page_state(pgdat, NR_SHMEM)),
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
K(node_page_state(pgdat, NR_SHMEM_THPS)),
K(node_page_state(pgdat, NR_SHMEM_PMDMAPPED)),
K(node_page_state(pgdat, NR_ANON_THPS)),
#endif
K(node_page_state(pgdat, NR_WRITEBACK_TEMP)),
node_page_state(pgdat, NR_KERNEL_STACK_KB),
#ifdef CONFIG_SHADOW_CALL_STACK
node_page_state(pgdat, NR_KERNEL_SCS_KB),
#endif
K(node_page_state(pgdat, NR_PAGETABLE)),
K(node_page_state(pgdat, NR_SECONDARY_PAGETABLE)),
pgdat->kswapd_failures >= MAX_RECLAIM_RETRIES ?
"yes" : "no");
}
for_each_populated_zone(zone) {
int i;
if (zone_idx(zone) > max_zone_idx)
continue;
if (show_mem_node_skip(filter, zone_to_nid(zone), nodemask))
continue;
free_pcp = 0;
for_each_online_cpu(cpu)
free_pcp += per_cpu_ptr(zone->per_cpu_pageset, cpu)->count;
show_node(zone);
printk(KERN_CONT
"%s"
" free:%lukB"
" boost:%lukB"
" min:%lukB"
" low:%lukB"
" high:%lukB"
" reserved_highatomic:%luKB"
" active_anon:%lukB"
" inactive_anon:%lukB"
" active_file:%lukB"
" inactive_file:%lukB"
" unevictable:%lukB"
" writepending:%lukB"
" present:%lukB"
" managed:%lukB"
" mlocked:%lukB"
" bounce:%lukB"
" free_pcp:%lukB"
" local_pcp:%ukB"
" free_cma:%lukB"
"\n",
zone->name,
K(zone_page_state(zone, NR_FREE_PAGES)),
K(zone->watermark_boost),
K(min_wmark_pages(zone)),
K(low_wmark_pages(zone)),
K(high_wmark_pages(zone)),
K(zone->nr_reserved_highatomic),
K(zone_page_state(zone, NR_ZONE_ACTIVE_ANON)),
K(zone_page_state(zone, NR_ZONE_INACTIVE_ANON)),
K(zone_page_state(zone, NR_ZONE_ACTIVE_FILE)),
K(zone_page_state(zone, NR_ZONE_INACTIVE_FILE)),
K(zone_page_state(zone, NR_ZONE_UNEVICTABLE)),
K(zone_page_state(zone, NR_ZONE_WRITE_PENDING)),
K(zone->present_pages),
K(zone_managed_pages(zone)),
K(zone_page_state(zone, NR_MLOCK)),
K(zone_page_state(zone, NR_BOUNCE)),
K(free_pcp),
K(this_cpu_read(zone->per_cpu_pageset->count)),
K(zone_page_state(zone, NR_FREE_CMA_PAGES)));
printk("lowmem_reserve[]:");
for (i = 0; i < MAX_NR_ZONES; i++)
printk(KERN_CONT " %ld", zone->lowmem_reserve[i]);
printk(KERN_CONT "\n");
}
for_each_populated_zone(zone) {
unsigned int order;
unsigned long nr[MAX_ORDER + 1], flags, total = 0;
unsigned char types[MAX_ORDER + 1];
if (zone_idx(zone) > max_zone_idx)
continue;
if (show_mem_node_skip(filter, zone_to_nid(zone), nodemask))
continue;
show_node(zone);
printk(KERN_CONT "%s: ", zone->name);
spin_lock_irqsave(&zone->lock, flags);
for (order = 0; order <= MAX_ORDER; order++) {
struct free_area *area = &zone->free_area[order];
int type;
nr[order] = area->nr_free;
total += nr[order] << order;
types[order] = 0;
for (type = 0; type < MIGRATE_TYPES; type++) {
if (!free_area_empty(area, type))
types[order] |= 1 << type;
}
}
spin_unlock_irqrestore(&zone->lock, flags);
for (order = 0; order <= MAX_ORDER; order++) {
printk(KERN_CONT "%lu*%lukB ",
nr[order], K(1UL) << order);
if (nr[order])
show_migration_types(types[order]);
}
printk(KERN_CONT "= %lukB\n", K(total));
}
for_each_online_node(nid) {
if (show_mem_node_skip(filter, nid, nodemask))
continue;
hugetlb_show_meminfo_node(nid);
}
printk("%ld total pagecache pages\n", global_node_page_state(NR_FILE_PAGES));
show_swap_cache_info();
}
void __show_mem(unsigned int filter, nodemask_t *nodemask, int max_zone_idx)
{
unsigned long total = 0, reserved = 0, highmem = 0;
struct zone *zone;
printk("Mem-Info:\n");
show_free_areas(filter, nodemask, max_zone_idx);
for_each_populated_zone(zone) {
total += zone->present_pages;
reserved += zone->present_pages - zone_managed_pages(zone);
if (is_highmem(zone))
highmem += zone->present_pages;
}
printk("%lu pages RAM\n", total);
printk("%lu pages HighMem/MovableOnly\n", highmem);
printk("%lu pages reserved\n", reserved);
#ifdef CONFIG_CMA
printk("%lu pages cma reserved\n", totalcma_pages);
#endif
#ifdef CONFIG_MEMORY_FAILURE
printk("%lu pages hwpoisoned\n", atomic_long_read(&num_poisoned_pages));
#endif
}
| linux-master | mm/show_mem.c |
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/spinlock.h>
#include <linux/mm.h>
#include <linux/memremap.h>
#include <linux/pagemap.h>
#include <linux/rmap.h>
#include <linux/swap.h>
#include <linux/swapops.h>
#include <linux/secretmem.h>
#include <linux/sched/signal.h>
#include <linux/rwsem.h>
#include <linux/hugetlb.h>
#include <linux/migrate.h>
#include <linux/mm_inline.h>
#include <linux/sched/mm.h>
#include <linux/shmem_fs.h>
#include <asm/mmu_context.h>
#include <asm/tlbflush.h>
#include "internal.h"
struct follow_page_context {
struct dev_pagemap *pgmap;
unsigned int page_mask;
};
static inline void sanity_check_pinned_pages(struct page **pages,
unsigned long npages)
{
if (!IS_ENABLED(CONFIG_DEBUG_VM))
return;
/*
* We only pin anonymous pages if they are exclusive. Once pinned, we
* can no longer turn them possibly shared and PageAnonExclusive() will
* stick around until the page is freed.
*
* We'd like to verify that our pinned anonymous pages are still mapped
* exclusively. The issue with anon THP is that we don't know how
* they are/were mapped when pinning them. However, for anon
* THP we can assume that either the given page (PTE-mapped THP) or
* the head page (PMD-mapped THP) should be PageAnonExclusive(). If
* neither is the case, there is certainly something wrong.
*/
for (; npages; npages--, pages++) {
struct page *page = *pages;
struct folio *folio = page_folio(page);
if (is_zero_page(page) ||
!folio_test_anon(folio))
continue;
if (!folio_test_large(folio) || folio_test_hugetlb(folio))
VM_BUG_ON_PAGE(!PageAnonExclusive(&folio->page), page);
else
/* Either a PTE-mapped or a PMD-mapped THP. */
VM_BUG_ON_PAGE(!PageAnonExclusive(&folio->page) &&
!PageAnonExclusive(page), page);
}
}
/*
* Return the folio with ref appropriately incremented,
* or NULL if that failed.
*/
static inline struct folio *try_get_folio(struct page *page, int refs)
{
struct folio *folio;
retry:
folio = page_folio(page);
if (WARN_ON_ONCE(folio_ref_count(folio) < 0))
return NULL;
if (unlikely(!folio_ref_try_add_rcu(folio, refs)))
return NULL;
/*
* At this point we have a stable reference to the folio; but it
* could be that between calling page_folio() and the refcount
* increment, the folio was split, in which case we'd end up
* holding a reference on a folio that has nothing to do with the page
* we were given anymore.
* So now that the folio is stable, recheck that the page still
* belongs to this folio.
*/
if (unlikely(page_folio(page) != folio)) {
if (!put_devmap_managed_page_refs(&folio->page, refs))
folio_put_refs(folio, refs);
goto retry;
}
return folio;
}
/**
* try_grab_folio() - Attempt to get or pin a folio.
* @page: pointer to page to be grabbed
* @refs: the value to (effectively) add to the folio's refcount
* @flags: gup flags: these are the FOLL_* flag values.
*
* "grab" names in this file mean, "look at flags to decide whether to use
* FOLL_PIN or FOLL_GET behavior, when incrementing the folio's refcount.
*
* Either FOLL_PIN or FOLL_GET (or neither) must be set, but not both at the
* same time. (That's true throughout the get_user_pages*() and
* pin_user_pages*() APIs.) Cases:
*
* FOLL_GET: folio's refcount will be incremented by @refs.
*
* FOLL_PIN on large folios: folio's refcount will be incremented by
* @refs, and its pincount will be incremented by @refs.
*
* FOLL_PIN on single-page folios: folio's refcount will be incremented by
* @refs * GUP_PIN_COUNTING_BIAS.
*
* Return: The folio containing @page (with refcount appropriately
* incremented) for success, or NULL upon failure. If neither FOLL_GET
* nor FOLL_PIN was set, that's considered failure, and furthermore,
* a likely bug in the caller, so a warning is also emitted.
*/
struct folio *try_grab_folio(struct page *page, int refs, unsigned int flags)
{
struct folio *folio;
if (WARN_ON_ONCE((flags & (FOLL_GET | FOLL_PIN)) == 0))
return NULL;
if (unlikely(!(flags & FOLL_PCI_P2PDMA) && is_pci_p2pdma_page(page)))
return NULL;
if (flags & FOLL_GET)
return try_get_folio(page, refs);
/* FOLL_PIN is set */
/*
* Don't take a pin on the zero page - it's not going anywhere
* and it is used in a *lot* of places.
*/
if (is_zero_page(page))
return page_folio(page);
folio = try_get_folio(page, refs);
if (!folio)
return NULL;
/*
* Can't do FOLL_LONGTERM + FOLL_PIN gup fast path if not in a
* right zone, so fail and let the caller fall back to the slow
* path.
*/
if (unlikely((flags & FOLL_LONGTERM) &&
!folio_is_longterm_pinnable(folio))) {
if (!put_devmap_managed_page_refs(&folio->page, refs))
folio_put_refs(folio, refs);
return NULL;
}
/*
* When pinning a large folio, use an exact count to track it.
*
* However, be sure to *also* increment the normal folio
* refcount field at least once, so that the folio really
* is pinned. That's why the refcount from the earlier
* try_get_folio() is left intact.
*/
if (folio_test_large(folio))
atomic_add(refs, &folio->_pincount);
else
folio_ref_add(folio,
refs * (GUP_PIN_COUNTING_BIAS - 1));
/*
* Adjust the pincount before re-checking the PTE for changes.
* This is essentially a smp_mb() and is paired with a memory
* barrier in page_try_share_anon_rmap().
*/
smp_mb__after_atomic();
node_stat_mod_folio(folio, NR_FOLL_PIN_ACQUIRED, refs);
return folio;
}
static void gup_put_folio(struct folio *folio, int refs, unsigned int flags)
{
if (flags & FOLL_PIN) {
if (is_zero_folio(folio))
return;
node_stat_mod_folio(folio, NR_FOLL_PIN_RELEASED, refs);
if (folio_test_large(folio))
atomic_sub(refs, &folio->_pincount);
else
refs *= GUP_PIN_COUNTING_BIAS;
}
if (!put_devmap_managed_page_refs(&folio->page, refs))
folio_put_refs(folio, refs);
}
/**
* try_grab_page() - elevate a page's refcount by a flag-dependent amount
* @page: pointer to page to be grabbed
* @flags: gup flags: these are the FOLL_* flag values.
*
* This might not do anything at all, depending on the flags argument.
*
* "grab" names in this file mean, "look at flags to decide whether to use
* FOLL_PIN or FOLL_GET behavior, when incrementing the page's refcount.
*
* Either FOLL_PIN or FOLL_GET (or neither) may be set, but not both at the same
* time. Cases: please see the try_grab_folio() documentation, with
* "refs=1".
*
* Return: 0 for success, or if no action was required (if neither FOLL_PIN
* nor FOLL_GET was set, nothing is done). A negative error code for failure:
*
* -ENOMEM FOLL_GET or FOLL_PIN was set, but the page could not
* be grabbed.
*/
int __must_check try_grab_page(struct page *page, unsigned int flags)
{
struct folio *folio = page_folio(page);
if (WARN_ON_ONCE(folio_ref_count(folio) <= 0))
return -ENOMEM;
if (unlikely(!(flags & FOLL_PCI_P2PDMA) && is_pci_p2pdma_page(page)))
return -EREMOTEIO;
if (flags & FOLL_GET)
folio_ref_inc(folio);
else if (flags & FOLL_PIN) {
/*
* Don't take a pin on the zero page - it's not going anywhere
* and it is used in a *lot* of places.
*/
if (is_zero_page(page))
return 0;
/*
* Similar to try_grab_folio(): be sure to *also*
* increment the normal page refcount field at least once,
* so that the page really is pinned.
*/
if (folio_test_large(folio)) {
folio_ref_add(folio, 1);
atomic_add(1, &folio->_pincount);
} else {
folio_ref_add(folio, GUP_PIN_COUNTING_BIAS);
}
node_stat_mod_folio(folio, NR_FOLL_PIN_ACQUIRED, 1);
}
return 0;
}
/**
* unpin_user_page() - release a dma-pinned page
* @page: pointer to page to be released
*
* Pages that were pinned via pin_user_pages*() must be released via either
* unpin_user_page(), or one of the unpin_user_pages*() routines. This is so
* that such pages can be separately tracked and uniquely handled. In
* particular, interactions with RDMA and filesystems need special handling.
*/
void unpin_user_page(struct page *page)
{
sanity_check_pinned_pages(&page, 1);
gup_put_folio(page_folio(page), 1, FOLL_PIN);
}
EXPORT_SYMBOL(unpin_user_page);
/**
* folio_add_pin - Try to get an additional pin on a pinned folio
* @folio: The folio to be pinned
*
* Get an additional pin on a folio we already have a pin on. Makes no change
* if the folio is a zero_page.
*/
void folio_add_pin(struct folio *folio)
{
if (is_zero_folio(folio))
return;
/*
* Similar to try_grab_folio(): be sure to *also* increment the normal
* page refcount field at least once, so that the page really is
* pinned.
*/
if (folio_test_large(folio)) {
WARN_ON_ONCE(atomic_read(&folio->_pincount) < 1);
folio_ref_inc(folio);
atomic_inc(&folio->_pincount);
} else {
WARN_ON_ONCE(folio_ref_count(folio) < GUP_PIN_COUNTING_BIAS);
folio_ref_add(folio, GUP_PIN_COUNTING_BIAS);
}
}
static inline struct folio *gup_folio_range_next(struct page *start,
unsigned long npages, unsigned long i, unsigned int *ntails)
{
struct page *next = nth_page(start, i);
struct folio *folio = page_folio(next);
unsigned int nr = 1;
if (folio_test_large(folio))
nr = min_t(unsigned int, npages - i,
folio_nr_pages(folio) - folio_page_idx(folio, next));
*ntails = nr;
return folio;
}
static inline struct folio *gup_folio_next(struct page **list,
unsigned long npages, unsigned long i, unsigned int *ntails)
{
struct folio *folio = page_folio(list[i]);
unsigned int nr;
for (nr = i + 1; nr < npages; nr++) {
if (page_folio(list[nr]) != folio)
break;
}
*ntails = nr - i;
return folio;
}
/**
* unpin_user_pages_dirty_lock() - release and optionally dirty gup-pinned pages
* @pages: array of pages to be maybe marked dirty, and definitely released.
* @npages: number of pages in the @pages array.
* @make_dirty: whether to mark the pages dirty
*
* "gup-pinned page" refers to a page that has had one of the get_user_pages()
* variants called on that page.
*
* For each page in the @pages array, make that page (or its head page, if a
* compound page) dirty, if @make_dirty is true, and if the page was previously
* listed as clean. In any case, releases all pages using unpin_user_page(),
* possibly via unpin_user_pages(), for the non-dirty case.
*
* Please see the unpin_user_page() documentation for details.
*
* set_page_dirty_lock() is used internally. If instead, set_page_dirty() is
* required, then the caller should a) verify that this is really correct,
* because _lock() is usually required, and b) hand code it:
* set_page_dirty_lock(), unpin_user_page().
*
*/
void unpin_user_pages_dirty_lock(struct page **pages, unsigned long npages,
bool make_dirty)
{
unsigned long i;
struct folio *folio;
unsigned int nr;
if (!make_dirty) {
unpin_user_pages(pages, npages);
return;
}
sanity_check_pinned_pages(pages, npages);
for (i = 0; i < npages; i += nr) {
folio = gup_folio_next(pages, npages, i, &nr);
/*
* Checking PageDirty at this point may race with
* clear_page_dirty_for_io(), but that's OK. Two key
* cases:
*
* 1) This code sees the page as already dirty, so it
* skips the call to set_page_dirty(). That could happen
* because clear_page_dirty_for_io() called
* page_mkclean(), followed by set_page_dirty().
* However, now the page is going to get written back,
* which meets the original intention of setting it
* dirty, so all is well: clear_page_dirty_for_io() goes
* on to call TestClearPageDirty(), and write the page
* back.
*
* 2) This code sees the page as clean, so it calls
* set_page_dirty(). The page stays dirty, despite being
* written back, so it gets written back again in the
* next writeback cycle. This is harmless.
*/
if (!folio_test_dirty(folio)) {
folio_lock(folio);
folio_mark_dirty(folio);
folio_unlock(folio);
}
gup_put_folio(folio, nr, FOLL_PIN);
}
}
EXPORT_SYMBOL(unpin_user_pages_dirty_lock);
/**
* unpin_user_page_range_dirty_lock() - release and optionally dirty
* gup-pinned page range
*
* @page: the starting page of a range maybe marked dirty, and definitely released.
* @npages: number of consecutive pages to release.
* @make_dirty: whether to mark the pages dirty
*
* "gup-pinned page range" refers to a range of pages that has had one of the
* pin_user_pages() variants called on that page.
*
* For the page ranges defined by [page .. page+npages], make that range (or
* its head pages, if a compound page) dirty, if @make_dirty is true, and if the
* page range was previously listed as clean.
*
* set_page_dirty_lock() is used internally. If instead, set_page_dirty() is
* required, then the caller should a) verify that this is really correct,
* because _lock() is usually required, and b) hand code it:
* set_page_dirty_lock(), unpin_user_page().
*
*/
void unpin_user_page_range_dirty_lock(struct page *page, unsigned long npages,
bool make_dirty)
{
unsigned long i;
struct folio *folio;
unsigned int nr;
for (i = 0; i < npages; i += nr) {
folio = gup_folio_range_next(page, npages, i, &nr);
if (make_dirty && !folio_test_dirty(folio)) {
folio_lock(folio);
folio_mark_dirty(folio);
folio_unlock(folio);
}
gup_put_folio(folio, nr, FOLL_PIN);
}
}
EXPORT_SYMBOL(unpin_user_page_range_dirty_lock);
static void unpin_user_pages_lockless(struct page **pages, unsigned long npages)
{
unsigned long i;
struct folio *folio;
unsigned int nr;
/*
* Don't perform any sanity checks because we might have raced with
* fork() and some anonymous pages might now actually be shared --
* which is why we're unpinning after all.
*/
for (i = 0; i < npages; i += nr) {
folio = gup_folio_next(pages, npages, i, &nr);
gup_put_folio(folio, nr, FOLL_PIN);
}
}
/**
* unpin_user_pages() - release an array of gup-pinned pages.
* @pages: array of pages to be marked dirty and released.
* @npages: number of pages in the @pages array.
*
* For each page in the @pages array, release the page using unpin_user_page().
*
* Please see the unpin_user_page() documentation for details.
*/
void unpin_user_pages(struct page **pages, unsigned long npages)
{
unsigned long i;
struct folio *folio;
unsigned int nr;
/*
* If this WARN_ON() fires, then the system *might* be leaking pages (by
* leaving them pinned), but probably not. More likely, gup/pup returned
* a hard -ERRNO error to the caller, who erroneously passed it here.
*/
if (WARN_ON(IS_ERR_VALUE(npages)))
return;
sanity_check_pinned_pages(pages, npages);
for (i = 0; i < npages; i += nr) {
folio = gup_folio_next(pages, npages, i, &nr);
gup_put_folio(folio, nr, FOLL_PIN);
}
}
EXPORT_SYMBOL(unpin_user_pages);
/*
* Set the MMF_HAS_PINNED if not set yet; after set it'll be there for the mm's
* lifecycle. Avoid setting the bit unless necessary, or it might cause write
* cache bouncing on large SMP machines for concurrent pinned gups.
*/
static inline void mm_set_has_pinned_flag(unsigned long *mm_flags)
{
if (!test_bit(MMF_HAS_PINNED, mm_flags))
set_bit(MMF_HAS_PINNED, mm_flags);
}
#ifdef CONFIG_MMU
static struct page *no_page_table(struct vm_area_struct *vma,
unsigned int flags)
{
/*
* When core dumping an enormous anonymous area that nobody
* has touched so far, we don't want to allocate unnecessary pages or
* page tables. Return error instead of NULL to skip handle_mm_fault,
* then get_dump_page() will return NULL to leave a hole in the dump.
* But we can only make this optimization where a hole would surely
* be zero-filled if handle_mm_fault() actually did handle it.
*/
if ((flags & FOLL_DUMP) &&
(vma_is_anonymous(vma) || !vma->vm_ops->fault))
return ERR_PTR(-EFAULT);
return NULL;
}
static int follow_pfn_pte(struct vm_area_struct *vma, unsigned long address,
pte_t *pte, unsigned int flags)
{
if (flags & FOLL_TOUCH) {
pte_t orig_entry = ptep_get(pte);
pte_t entry = orig_entry;
if (flags & FOLL_WRITE)
entry = pte_mkdirty(entry);
entry = pte_mkyoung(entry);
if (!pte_same(orig_entry, entry)) {
set_pte_at(vma->vm_mm, address, pte, entry);
update_mmu_cache(vma, address, pte);
}
}
/* Proper page table entry exists, but no corresponding struct page */
return -EEXIST;
}
/* FOLL_FORCE can write to even unwritable PTEs in COW mappings. */
static inline bool can_follow_write_pte(pte_t pte, struct page *page,
struct vm_area_struct *vma,
unsigned int flags)
{
/* If the pte is writable, we can write to the page. */
if (pte_write(pte))
return true;
/* Maybe FOLL_FORCE is set to override it? */
if (!(flags & FOLL_FORCE))
return false;
/* But FOLL_FORCE has no effect on shared mappings */
if (vma->vm_flags & (VM_MAYSHARE | VM_SHARED))
return false;
/* ... or read-only private ones */
if (!(vma->vm_flags & VM_MAYWRITE))
return false;
/* ... or already writable ones that just need to take a write fault */
if (vma->vm_flags & VM_WRITE)
return false;
/*
* See can_change_pte_writable(): we broke COW and could map the page
* writable if we have an exclusive anonymous page ...
*/
if (!page || !PageAnon(page) || !PageAnonExclusive(page))
return false;
/* ... and a write-fault isn't required for other reasons. */
if (vma_soft_dirty_enabled(vma) && !pte_soft_dirty(pte))
return false;
return !userfaultfd_pte_wp(vma, pte);
}
static struct page *follow_page_pte(struct vm_area_struct *vma,
unsigned long address, pmd_t *pmd, unsigned int flags,
struct dev_pagemap **pgmap)
{
struct mm_struct *mm = vma->vm_mm;
struct page *page;
spinlock_t *ptl;
pte_t *ptep, pte;
int ret;
/* FOLL_GET and FOLL_PIN are mutually exclusive. */
if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) ==
(FOLL_PIN | FOLL_GET)))
return ERR_PTR(-EINVAL);
ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
if (!ptep)
return no_page_table(vma, flags);
pte = ptep_get(ptep);
if (!pte_present(pte))
goto no_page;
if (pte_protnone(pte) && !gup_can_follow_protnone(vma, flags))
goto no_page;
page = vm_normal_page(vma, address, pte);
/*
* We only care about anon pages in can_follow_write_pte() and don't
* have to worry about pte_devmap() because they are never anon.
*/
if ((flags & FOLL_WRITE) &&
!can_follow_write_pte(pte, page, vma, flags)) {
page = NULL;
goto out;
}
if (!page && pte_devmap(pte) && (flags & (FOLL_GET | FOLL_PIN))) {
/*
* Only return device mapping pages in the FOLL_GET or FOLL_PIN
* case since they are only valid while holding the pgmap
* reference.
*/
*pgmap = get_dev_pagemap(pte_pfn(pte), *pgmap);
if (*pgmap)
page = pte_page(pte);
else
goto no_page;
} else if (unlikely(!page)) {
if (flags & FOLL_DUMP) {
/* Avoid special (like zero) pages in core dumps */
page = ERR_PTR(-EFAULT);
goto out;
}
if (is_zero_pfn(pte_pfn(pte))) {
page = pte_page(pte);
} else {
ret = follow_pfn_pte(vma, address, ptep, flags);
page = ERR_PTR(ret);
goto out;
}
}
if (!pte_write(pte) && gup_must_unshare(vma, flags, page)) {
page = ERR_PTR(-EMLINK);
goto out;
}
VM_BUG_ON_PAGE((flags & FOLL_PIN) && PageAnon(page) &&
!PageAnonExclusive(page), page);
/* try_grab_page() does nothing unless FOLL_GET or FOLL_PIN is set. */
ret = try_grab_page(page, flags);
if (unlikely(ret)) {
page = ERR_PTR(ret);
goto out;
}
/*
* We need to make the page accessible if and only if we are going
* to access its content (the FOLL_PIN case). Please see
* Documentation/core-api/pin_user_pages.rst for details.
*/
if (flags & FOLL_PIN) {
ret = arch_make_page_accessible(page);
if (ret) {
unpin_user_page(page);
page = ERR_PTR(ret);
goto out;
}
}
if (flags & FOLL_TOUCH) {
if ((flags & FOLL_WRITE) &&
!pte_dirty(pte) && !PageDirty(page))
set_page_dirty(page);
/*
* pte_mkyoung() would be more correct here, but atomic care
* is needed to avoid losing the dirty bit: it is easier to use
* mark_page_accessed().
*/
mark_page_accessed(page);
}
out:
pte_unmap_unlock(ptep, ptl);
return page;
no_page:
pte_unmap_unlock(ptep, ptl);
if (!pte_none(pte))
return NULL;
return no_page_table(vma, flags);
}
static struct page *follow_pmd_mask(struct vm_area_struct *vma,
unsigned long address, pud_t *pudp,
unsigned int flags,
struct follow_page_context *ctx)
{
pmd_t *pmd, pmdval;
spinlock_t *ptl;
struct page *page;
struct mm_struct *mm = vma->vm_mm;
pmd = pmd_offset(pudp, address);
pmdval = pmdp_get_lockless(pmd);
if (pmd_none(pmdval))
return no_page_table(vma, flags);
if (!pmd_present(pmdval))
return no_page_table(vma, flags);
if (pmd_devmap(pmdval)) {
ptl = pmd_lock(mm, pmd);
page = follow_devmap_pmd(vma, address, pmd, flags, &ctx->pgmap);
spin_unlock(ptl);
if (page)
return page;
}
if (likely(!pmd_trans_huge(pmdval)))
return follow_page_pte(vma, address, pmd, flags, &ctx->pgmap);
if (pmd_protnone(pmdval) && !gup_can_follow_protnone(vma, flags))
return no_page_table(vma, flags);
ptl = pmd_lock(mm, pmd);
if (unlikely(!pmd_present(*pmd))) {
spin_unlock(ptl);
return no_page_table(vma, flags);
}
if (unlikely(!pmd_trans_huge(*pmd))) {
spin_unlock(ptl);
return follow_page_pte(vma, address, pmd, flags, &ctx->pgmap);
}
if (flags & FOLL_SPLIT_PMD) {
spin_unlock(ptl);
split_huge_pmd(vma, pmd, address);
/* If pmd was left empty, stuff a page table in there quickly */
return pte_alloc(mm, pmd) ? ERR_PTR(-ENOMEM) :
follow_page_pte(vma, address, pmd, flags, &ctx->pgmap);
}
page = follow_trans_huge_pmd(vma, address, pmd, flags);
spin_unlock(ptl);
ctx->page_mask = HPAGE_PMD_NR - 1;
return page;
}
static struct page *follow_pud_mask(struct vm_area_struct *vma,
unsigned long address, p4d_t *p4dp,
unsigned int flags,
struct follow_page_context *ctx)
{
pud_t *pud;
spinlock_t *ptl;
struct page *page;
struct mm_struct *mm = vma->vm_mm;
pud = pud_offset(p4dp, address);
if (pud_none(*pud))
return no_page_table(vma, flags);
if (pud_devmap(*pud)) {
ptl = pud_lock(mm, pud);
page = follow_devmap_pud(vma, address, pud, flags, &ctx->pgmap);
spin_unlock(ptl);
if (page)
return page;
}
if (unlikely(pud_bad(*pud)))
return no_page_table(vma, flags);
return follow_pmd_mask(vma, address, pud, flags, ctx);
}
static struct page *follow_p4d_mask(struct vm_area_struct *vma,
unsigned long address, pgd_t *pgdp,
unsigned int flags,
struct follow_page_context *ctx)
{
p4d_t *p4d;
p4d = p4d_offset(pgdp, address);
if (p4d_none(*p4d))
return no_page_table(vma, flags);
BUILD_BUG_ON(p4d_huge(*p4d));
if (unlikely(p4d_bad(*p4d)))
return no_page_table(vma, flags);
return follow_pud_mask(vma, address, p4d, flags, ctx);
}
/**
* follow_page_mask - look up a page descriptor from a user-virtual address
* @vma: vm_area_struct mapping @address
* @address: virtual address to look up
* @flags: flags modifying lookup behaviour
* @ctx: contains dev_pagemap for %ZONE_DEVICE memory pinning and a
* pointer to output page_mask
*
* @flags can have FOLL_ flags set, defined in <linux/mm.h>
*
* When getting pages from ZONE_DEVICE memory, the @ctx->pgmap caches
* the device's dev_pagemap metadata to avoid repeating expensive lookups.
*
* When getting an anonymous page and the caller has to trigger unsharing
* of a shared anonymous page first, -EMLINK is returned. The caller should
* trigger a fault with FAULT_FLAG_UNSHARE set. Note that unsharing is only
* relevant with FOLL_PIN and !FOLL_WRITE.
*
* On output, the @ctx->page_mask is set according to the size of the page.
*
* Return: the mapped (struct page *), %NULL if no mapping exists, or
* an error pointer if there is a mapping to something not represented
* by a page descriptor (see also vm_normal_page()).
*/
static struct page *follow_page_mask(struct vm_area_struct *vma,
unsigned long address, unsigned int flags,
struct follow_page_context *ctx)
{
pgd_t *pgd;
struct mm_struct *mm = vma->vm_mm;
ctx->page_mask = 0;
/*
* Call hugetlb_follow_page_mask for hugetlb vmas as it will use
* special hugetlb page table walking code. This eliminates the
* need to check for hugetlb entries in the general walking code.
*/
if (is_vm_hugetlb_page(vma))
return hugetlb_follow_page_mask(vma, address, flags,
&ctx->page_mask);
pgd = pgd_offset(mm, address);
if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
return no_page_table(vma, flags);
return follow_p4d_mask(vma, address, pgd, flags, ctx);
}
struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
unsigned int foll_flags)
{
struct follow_page_context ctx = { NULL };
struct page *page;
if (vma_is_secretmem(vma))
return NULL;
if (WARN_ON_ONCE(foll_flags & FOLL_PIN))
return NULL;
/*
* We never set FOLL_HONOR_NUMA_FAULT because callers don't expect
* to fail on PROT_NONE-mapped pages.
*/
page = follow_page_mask(vma, address, foll_flags, &ctx);
if (ctx.pgmap)
put_dev_pagemap(ctx.pgmap);
return page;
}
static int get_gate_page(struct mm_struct *mm, unsigned long address,
unsigned int gup_flags, struct vm_area_struct **vma,
struct page **page)
{
pgd_t *pgd;
p4d_t *p4d;
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
pte_t entry;
int ret = -EFAULT;
/* user gate pages are read-only */
if (gup_flags & FOLL_WRITE)
return -EFAULT;
if (address > TASK_SIZE)
pgd = pgd_offset_k(address);
else
pgd = pgd_offset_gate(mm, address);
if (pgd_none(*pgd))
return -EFAULT;
p4d = p4d_offset(pgd, address);
if (p4d_none(*p4d))
return -EFAULT;
pud = pud_offset(p4d, address);
if (pud_none(*pud))
return -EFAULT;
pmd = pmd_offset(pud, address);
if (!pmd_present(*pmd))
return -EFAULT;
pte = pte_offset_map(pmd, address);
if (!pte)
return -EFAULT;
entry = ptep_get(pte);
if (pte_none(entry))
goto unmap;
*vma = get_gate_vma(mm);
if (!page)
goto out;
*page = vm_normal_page(*vma, address, entry);
if (!*page) {
if ((gup_flags & FOLL_DUMP) || !is_zero_pfn(pte_pfn(entry)))
goto unmap;
*page = pte_page(entry);
}
ret = try_grab_page(*page, gup_flags);
if (unlikely(ret))
goto unmap;
out:
ret = 0;
unmap:
pte_unmap(pte);
return ret;
}
/*
* mmap_lock must be held on entry. If @flags has FOLL_UNLOCKABLE but not
* FOLL_NOWAIT, the mmap_lock may be released. If it is, *@locked will be set
* to 0 and -EBUSY returned.
*/
static int faultin_page(struct vm_area_struct *vma,
unsigned long address, unsigned int *flags, bool unshare,
int *locked)
{
unsigned int fault_flags = 0;
vm_fault_t ret;
if (*flags & FOLL_NOFAULT)
return -EFAULT;
if (*flags & FOLL_WRITE)
fault_flags |= FAULT_FLAG_WRITE;
if (*flags & FOLL_REMOTE)
fault_flags |= FAULT_FLAG_REMOTE;
if (*flags & FOLL_UNLOCKABLE) {
fault_flags |= FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
/*
* FAULT_FLAG_INTERRUPTIBLE is opt-in. GUP callers must set
* FOLL_INTERRUPTIBLE to enable FAULT_FLAG_INTERRUPTIBLE.
* That's because some callers may not be prepared to
* handle early exits caused by non-fatal signals.
*/
if (*flags & FOLL_INTERRUPTIBLE)
fault_flags |= FAULT_FLAG_INTERRUPTIBLE;
}
if (*flags & FOLL_NOWAIT)
fault_flags |= FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_RETRY_NOWAIT;
if (*flags & FOLL_TRIED) {
/*
* Note: FAULT_FLAG_ALLOW_RETRY and FAULT_FLAG_TRIED
* can co-exist
*/
fault_flags |= FAULT_FLAG_TRIED;
}
if (unshare) {
fault_flags |= FAULT_FLAG_UNSHARE;
/* FAULT_FLAG_WRITE and FAULT_FLAG_UNSHARE are incompatible */
VM_BUG_ON(fault_flags & FAULT_FLAG_WRITE);
}
ret = handle_mm_fault(vma, address, fault_flags, NULL);
if (ret & VM_FAULT_COMPLETED) {
/*
* With FAULT_FLAG_RETRY_NOWAIT we'll never release the
* mmap lock in the page fault handler. Sanity check this.
*/
WARN_ON_ONCE(fault_flags & FAULT_FLAG_RETRY_NOWAIT);
*locked = 0;
/*
* We should do the same as VM_FAULT_RETRY, but let's not
* return -EBUSY since that's not reflecting the reality of
* what has happened - we've just fully completed a page
* fault, with the mmap lock released. Use -EAGAIN to show
* that we want to take the mmap lock _again_.
*/
return -EAGAIN;
}
if (ret & VM_FAULT_ERROR) {
int err = vm_fault_to_errno(ret, *flags);
if (err)
return err;
BUG();
}
if (ret & VM_FAULT_RETRY) {
if (!(fault_flags & FAULT_FLAG_RETRY_NOWAIT))
*locked = 0;
return -EBUSY;
}
return 0;
}
/*
* Writing to file-backed mappings which require folio dirty tracking using GUP
* is a fundamentally broken operation, as kernel write access to GUP mappings
* do not adhere to the semantics expected by a file system.
*
* Consider the following scenario:-
*
* 1. A folio is written to via GUP which write-faults the memory, notifying
* the file system and dirtying the folio.
* 2. Later, writeback is triggered, resulting in the folio being cleaned and
* the PTE being marked read-only.
* 3. The GUP caller writes to the folio, as it is mapped read/write via the
* direct mapping.
* 4. The GUP caller, now done with the page, unpins it and sets it dirty
* (though it does not have to).
*
* This results in both data being written to a folio without writenotify, and
* the folio being dirtied unexpectedly (if the caller decides to do so).
*/
static bool writable_file_mapping_allowed(struct vm_area_struct *vma,
unsigned long gup_flags)
{
/*
* If we aren't pinning then no problematic write can occur. A long term
* pin is the most egregious case so this is the case we disallow.
*/
if ((gup_flags & (FOLL_PIN | FOLL_LONGTERM)) !=
(FOLL_PIN | FOLL_LONGTERM))
return true;
/*
* If the VMA does not require dirty tracking then no problematic write
* can occur either.
*/
return !vma_needs_dirty_tracking(vma);
}
static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags)
{
vm_flags_t vm_flags = vma->vm_flags;
int write = (gup_flags & FOLL_WRITE);
int foreign = (gup_flags & FOLL_REMOTE);
bool vma_anon = vma_is_anonymous(vma);
if (vm_flags & (VM_IO | VM_PFNMAP))
return -EFAULT;
if ((gup_flags & FOLL_ANON) && !vma_anon)
return -EFAULT;
if ((gup_flags & FOLL_LONGTERM) && vma_is_fsdax(vma))
return -EOPNOTSUPP;
if (vma_is_secretmem(vma))
return -EFAULT;
if (write) {
if (!vma_anon &&
!writable_file_mapping_allowed(vma, gup_flags))
return -EFAULT;
if (!(vm_flags & VM_WRITE) || (vm_flags & VM_SHADOW_STACK)) {
if (!(gup_flags & FOLL_FORCE))
return -EFAULT;
/* hugetlb does not support FOLL_FORCE|FOLL_WRITE. */
if (is_vm_hugetlb_page(vma))
return -EFAULT;
/*
* We used to let the write,force case do COW in a
* VM_MAYWRITE VM_SHARED !VM_WRITE vma, so ptrace could
* set a breakpoint in a read-only mapping of an
* executable, without corrupting the file (yet only
* when that file had been opened for writing!).
* Anon pages in shared mappings are surprising: now
* just reject it.
*/
if (!is_cow_mapping(vm_flags))
return -EFAULT;
}
} else if (!(vm_flags & VM_READ)) {
if (!(gup_flags & FOLL_FORCE))
return -EFAULT;
/*
* Is there actually any vma we can reach here which does not
* have VM_MAYREAD set?
*/
if (!(vm_flags & VM_MAYREAD))
return -EFAULT;
}
/*
* gups are always data accesses, not instruction
* fetches, so execute=false here
*/
if (!arch_vma_access_permitted(vma, write, false, foreign))
return -EFAULT;
return 0;
}
/*
* This is "vma_lookup()", but with a warning if we would have
* historically expanded the stack in the GUP code.
*/
static struct vm_area_struct *gup_vma_lookup(struct mm_struct *mm,
unsigned long addr)
{
#ifdef CONFIG_STACK_GROWSUP
return vma_lookup(mm, addr);
#else
static volatile unsigned long next_warn;
struct vm_area_struct *vma;
unsigned long now, next;
vma = find_vma(mm, addr);
if (!vma || (addr >= vma->vm_start))
return vma;
/* Only warn for half-way relevant accesses */
if (!(vma->vm_flags & VM_GROWSDOWN))
return NULL;
if (vma->vm_start - addr > 65536)
return NULL;
/* Let's not warn more than once an hour.. */
now = jiffies; next = next_warn;
if (next && time_before(now, next))
return NULL;
next_warn = now + 60*60*HZ;
/* Let people know things may have changed. */
pr_warn("GUP no longer grows the stack in %s (%d): %lx-%lx (%lx)\n",
current->comm, task_pid_nr(current),
vma->vm_start, vma->vm_end, addr);
dump_stack();
return NULL;
#endif
}
/**
* __get_user_pages() - pin user pages in memory
* @mm: mm_struct of target mm
* @start: starting user address
* @nr_pages: number of pages from start to pin
* @gup_flags: flags modifying pin behaviour
* @pages: array that receives pointers to the pages pinned.
* Should be at least nr_pages long. Or NULL, if caller
* only intends to ensure the pages are faulted in.
* @locked: whether we're still with the mmap_lock held
*
* Returns either number of pages pinned (which may be less than the
* number requested), or an error. Details about the return value:
*
* -- If nr_pages is 0, returns 0.
* -- If nr_pages is >0, but no pages were pinned, returns -errno.
* -- If nr_pages is >0, and some pages were pinned, returns the number of
* pages pinned. Again, this may be less than nr_pages.
* -- 0 return value is possible when the fault would need to be retried.
*
* The caller is responsible for releasing returned @pages, via put_page().
*
* Must be called with mmap_lock held. It may be released. See below.
*
* __get_user_pages walks a process's page tables and takes a reference to
* each struct page that each user address corresponds to at a given
* instant. That is, it takes the page that would be accessed if a user
* thread accesses the given user virtual address at that instant.
*
* This does not guarantee that the page exists in the user mappings when
* __get_user_pages returns, and there may even be a completely different
* page there in some cases (eg. if mmapped pagecache has been invalidated
* and subsequently re-faulted). However it does guarantee that the page
* won't be freed completely. And mostly callers simply care that the page
* contains data that was valid *at some point in time*. Typically, an IO
* or similar operation cannot guarantee anything stronger anyway because
* locks can't be held over the syscall boundary.
*
* If @gup_flags & FOLL_WRITE == 0, the page must not be written to. If
* the page is written to, set_page_dirty (or set_page_dirty_lock, as
* appropriate) must be called after the page is finished with, and
* before put_page is called.
*
* If FOLL_UNLOCKABLE is set without FOLL_NOWAIT then the mmap_lock may
* be released. If this happens *@locked will be set to 0 on return.
*
* A caller using such a combination of @gup_flags must therefore hold the
* mmap_lock for reading only, and recognize when it's been released. Otherwise,
* it must be held for either reading or writing and will not be released.
*
* In most cases, get_user_pages or get_user_pages_fast should be used
* instead of __get_user_pages. __get_user_pages should be used only if
* you need some special @gup_flags.
*/
static long __get_user_pages(struct mm_struct *mm,
unsigned long start, unsigned long nr_pages,
unsigned int gup_flags, struct page **pages,
int *locked)
{
long ret = 0, i = 0;
struct vm_area_struct *vma = NULL;
struct follow_page_context ctx = { NULL };
if (!nr_pages)
return 0;
start = untagged_addr_remote(mm, start);
VM_BUG_ON(!!pages != !!(gup_flags & (FOLL_GET | FOLL_PIN)));
do {
struct page *page;
unsigned int foll_flags = gup_flags;
unsigned int page_increm;
/* first iteration or cross vma bound */
if (!vma || start >= vma->vm_end) {
vma = gup_vma_lookup(mm, start);
if (!vma && in_gate_area(mm, start)) {
ret = get_gate_page(mm, start & PAGE_MASK,
gup_flags, &vma,
pages ? &page : NULL);
if (ret)
goto out;
ctx.page_mask = 0;
goto next_page;
}
if (!vma) {
ret = -EFAULT;
goto out;
}
ret = check_vma_flags(vma, gup_flags);
if (ret)
goto out;
}
retry:
/*
* If we have a pending SIGKILL, don't keep faulting pages and
* potentially allocating memory.
*/
if (fatal_signal_pending(current)) {
ret = -EINTR;
goto out;
}
cond_resched();
page = follow_page_mask(vma, start, foll_flags, &ctx);
if (!page || PTR_ERR(page) == -EMLINK) {
ret = faultin_page(vma, start, &foll_flags,
PTR_ERR(page) == -EMLINK, locked);
switch (ret) {
case 0:
goto retry;
case -EBUSY:
case -EAGAIN:
ret = 0;
fallthrough;
case -EFAULT:
case -ENOMEM:
case -EHWPOISON:
goto out;
}
BUG();
} else if (PTR_ERR(page) == -EEXIST) {
/*
* Proper page table entry exists, but no corresponding
* struct page. If the caller expects **pages to be
* filled in, bail out now, because that can't be done
* for this page.
*/
if (pages) {
ret = PTR_ERR(page);
goto out;
}
} else if (IS_ERR(page)) {
ret = PTR_ERR(page);
goto out;
}
next_page:
page_increm = 1 + (~(start >> PAGE_SHIFT) & ctx.page_mask);
if (page_increm > nr_pages)
page_increm = nr_pages;
if (pages) {
struct page *subpage;
unsigned int j;
/*
* This must be a large folio (and doesn't need to
* be the whole folio; it can be part of it), do
* the refcount work for all the subpages too.
*
* NOTE: here the page may not be the head page
* e.g. when start addr is not thp-size aligned.
* try_grab_folio() should have taken care of tail
* pages.
*/
if (page_increm > 1) {
struct folio *folio;
/*
* Since we already hold refcount on the
* large folio, this should never fail.
*/
folio = try_grab_folio(page, page_increm - 1,
foll_flags);
if (WARN_ON_ONCE(!folio)) {
/*
* Release the 1st page ref if the
* folio is problematic, fail hard.
*/
gup_put_folio(page_folio(page), 1,
foll_flags);
ret = -EFAULT;
goto out;
}
}
for (j = 0; j < page_increm; j++) {
subpage = nth_page(page, j);
pages[i + j] = subpage;
flush_anon_page(vma, subpage, start + j * PAGE_SIZE);
flush_dcache_page(subpage);
}
}
i += page_increm;
start += page_increm * PAGE_SIZE;
nr_pages -= page_increm;
} while (nr_pages);
out:
if (ctx.pgmap)
put_dev_pagemap(ctx.pgmap);
return i ? i : ret;
}
static bool vma_permits_fault(struct vm_area_struct *vma,
unsigned int fault_flags)
{
bool write = !!(fault_flags & FAULT_FLAG_WRITE);
bool foreign = !!(fault_flags & FAULT_FLAG_REMOTE);
vm_flags_t vm_flags = write ? VM_WRITE : VM_READ;
if (!(vm_flags & vma->vm_flags))
return false;
/*
* The architecture might have a hardware protection
* mechanism other than read/write that can deny access.
*
* gup always represents data access, not instruction
* fetches, so execute=false here:
*/
if (!arch_vma_access_permitted(vma, write, false, foreign))
return false;
return true;
}
/**
* fixup_user_fault() - manually resolve a user page fault
* @mm: mm_struct of target mm
* @address: user address
* @fault_flags:flags to pass down to handle_mm_fault()
* @unlocked: did we unlock the mmap_lock while retrying, maybe NULL if caller
* does not allow retry. If NULL, the caller must guarantee
* that fault_flags does not contain FAULT_FLAG_ALLOW_RETRY.
*
* This is meant to be called in the specific scenario where for locking reasons
* we try to access user memory in atomic context (within a pagefault_disable()
* section), this returns -EFAULT, and we want to resolve the user fault before
* trying again.
*
* Typically this is meant to be used by the futex code.
*
* The main difference with get_user_pages() is that this function will
* unconditionally call handle_mm_fault() which will in turn perform all the
* necessary SW fixup of the dirty and young bits in the PTE, while
* get_user_pages() only guarantees to update these in the struct page.
*
* This is important for some architectures where those bits also gate the
* access permission to the page because they are maintained in software. On
* such architectures, gup() will not be enough to make a subsequent access
* succeed.
*
* This function will not return with an unlocked mmap_lock. So it has not the
* same semantics wrt the @mm->mmap_lock as does filemap_fault().
*/
int fixup_user_fault(struct mm_struct *mm,
unsigned long address, unsigned int fault_flags,
bool *unlocked)
{
struct vm_area_struct *vma;
vm_fault_t ret;
address = untagged_addr_remote(mm, address);
if (unlocked)
fault_flags |= FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
retry:
vma = gup_vma_lookup(mm, address);
if (!vma)
return -EFAULT;
if (!vma_permits_fault(vma, fault_flags))
return -EFAULT;
if ((fault_flags & FAULT_FLAG_KILLABLE) &&
fatal_signal_pending(current))
return -EINTR;
ret = handle_mm_fault(vma, address, fault_flags, NULL);
if (ret & VM_FAULT_COMPLETED) {
/*
* NOTE: it's a pity that we need to retake the lock here
* to pair with the unlock() in the callers. Ideally we
* could tell the callers so they do not need to unlock.
*/
mmap_read_lock(mm);
*unlocked = true;
return 0;
}
if (ret & VM_FAULT_ERROR) {
int err = vm_fault_to_errno(ret, 0);
if (err)
return err;
BUG();
}
if (ret & VM_FAULT_RETRY) {
mmap_read_lock(mm);
*unlocked = true;
fault_flags |= FAULT_FLAG_TRIED;
goto retry;
}
return 0;
}
EXPORT_SYMBOL_GPL(fixup_user_fault);
/*
* GUP always responds to fatal signals. When FOLL_INTERRUPTIBLE is
* specified, it'll also respond to generic signals. The caller of GUP
* that has FOLL_INTERRUPTIBLE should take care of the GUP interruption.
*/
static bool gup_signal_pending(unsigned int flags)
{
if (fatal_signal_pending(current))
return true;
if (!(flags & FOLL_INTERRUPTIBLE))
return false;
return signal_pending(current);
}
/*
* Locking: (*locked == 1) means that the mmap_lock has already been acquired by
* the caller. This function may drop the mmap_lock. If it does so, then it will
* set (*locked = 0).
*
* (*locked == 0) means that the caller expects this function to acquire and
* drop the mmap_lock. Therefore, the value of *locked will still be zero when
* the function returns, even though it may have changed temporarily during
* function execution.
*
* Please note that this function, unlike __get_user_pages(), will not return 0
* for nr_pages > 0, unless FOLL_NOWAIT is used.
*/
static __always_inline long __get_user_pages_locked(struct mm_struct *mm,
unsigned long start,
unsigned long nr_pages,
struct page **pages,
int *locked,
unsigned int flags)
{
long ret, pages_done;
bool must_unlock = false;
/*
* The internal caller expects GUP to manage the lock internally and the
* lock must be released when this returns.
*/
if (!*locked) {
if (mmap_read_lock_killable(mm))
return -EAGAIN;
must_unlock = true;
*locked = 1;
}
else
mmap_assert_locked(mm);
if (flags & FOLL_PIN)
mm_set_has_pinned_flag(&mm->flags);
/*
* FOLL_PIN and FOLL_GET are mutually exclusive. Traditional behavior
* is to set FOLL_GET if the caller wants pages[] filled in (but has
* carelessly failed to specify FOLL_GET), so keep doing that, but only
* for FOLL_GET, not for the newer FOLL_PIN.
*
* FOLL_PIN always expects pages to be non-null, but no need to assert
* that here, as any failures will be obvious enough.
*/
if (pages && !(flags & FOLL_PIN))
flags |= FOLL_GET;
pages_done = 0;
for (;;) {
ret = __get_user_pages(mm, start, nr_pages, flags, pages,
locked);
if (!(flags & FOLL_UNLOCKABLE)) {
/* VM_FAULT_RETRY couldn't trigger, bypass */
pages_done = ret;
break;
}
/* VM_FAULT_RETRY or VM_FAULT_COMPLETED cannot return errors */
if (!*locked) {
BUG_ON(ret < 0);
BUG_ON(ret >= nr_pages);
}
if (ret > 0) {
nr_pages -= ret;
pages_done += ret;
if (!nr_pages)
break;
}
if (*locked) {
/*
* VM_FAULT_RETRY didn't trigger or it was a
* FOLL_NOWAIT.
*/
if (!pages_done)
pages_done = ret;
break;
}
/*
* VM_FAULT_RETRY triggered, so seek to the faulting offset.
* For the prefault case (!pages) we only update counts.
*/
if (likely(pages))
pages += ret;
start += ret << PAGE_SHIFT;
/* The lock was temporarily dropped, so we must unlock later */
must_unlock = true;
retry:
/*
* Repeat on the address that fired VM_FAULT_RETRY
* with both FAULT_FLAG_ALLOW_RETRY and
* FAULT_FLAG_TRIED. Note that GUP can be interrupted
* by fatal signals of even common signals, depending on
* the caller's request. So we need to check it before we
* start trying again otherwise it can loop forever.
*/
if (gup_signal_pending(flags)) {
if (!pages_done)
pages_done = -EINTR;
break;
}
ret = mmap_read_lock_killable(mm);
if (ret) {
BUG_ON(ret > 0);
if (!pages_done)
pages_done = ret;
break;
}
*locked = 1;
ret = __get_user_pages(mm, start, 1, flags | FOLL_TRIED,
pages, locked);
if (!*locked) {
/* Continue to retry until we succeeded */
BUG_ON(ret != 0);
goto retry;
}
if (ret != 1) {
BUG_ON(ret > 1);
if (!pages_done)
pages_done = ret;
break;
}
nr_pages--;
pages_done++;
if (!nr_pages)
break;
if (likely(pages))
pages++;
start += PAGE_SIZE;
}
if (must_unlock && *locked) {
/*
* We either temporarily dropped the lock, or the caller
* requested that we both acquire and drop the lock. Either way,
* we must now unlock, and notify the caller of that state.
*/
mmap_read_unlock(mm);
*locked = 0;
}
return pages_done;
}
/**
* populate_vma_page_range() - populate a range of pages in the vma.
* @vma: target vma
* @start: start address
* @end: end address
* @locked: whether the mmap_lock is still held
*
* This takes care of mlocking the pages too if VM_LOCKED is set.
*
* Return either number of pages pinned in the vma, or a negative error
* code on error.
*
* vma->vm_mm->mmap_lock must be held.
*
* If @locked is NULL, it may be held for read or write and will
* be unperturbed.
*
* If @locked is non-NULL, it must held for read only and may be
* released. If it's released, *@locked will be set to 0.
*/
long populate_vma_page_range(struct vm_area_struct *vma,
unsigned long start, unsigned long end, int *locked)
{
struct mm_struct *mm = vma->vm_mm;
unsigned long nr_pages = (end - start) / PAGE_SIZE;
int local_locked = 1;
int gup_flags;
long ret;
VM_BUG_ON(!PAGE_ALIGNED(start));
VM_BUG_ON(!PAGE_ALIGNED(end));
VM_BUG_ON_VMA(start < vma->vm_start, vma);
VM_BUG_ON_VMA(end > vma->vm_end, vma);
mmap_assert_locked(mm);
/*
* Rightly or wrongly, the VM_LOCKONFAULT case has never used
* faultin_page() to break COW, so it has no work to do here.
*/
if (vma->vm_flags & VM_LOCKONFAULT)
return nr_pages;
gup_flags = FOLL_TOUCH;
/*
* We want to touch writable mappings with a write fault in order
* to break COW, except for shared mappings because these don't COW
* and we would not want to dirty them for nothing.
*/
if ((vma->vm_flags & (VM_WRITE | VM_SHARED)) == VM_WRITE)
gup_flags |= FOLL_WRITE;
/*
* We want mlock to succeed for regions that have any permissions
* other than PROT_NONE.
*/
if (vma_is_accessible(vma))
gup_flags |= FOLL_FORCE;
if (locked)
gup_flags |= FOLL_UNLOCKABLE;
/*
* We made sure addr is within a VMA, so the following will
* not result in a stack expansion that recurses back here.
*/
ret = __get_user_pages(mm, start, nr_pages, gup_flags,
NULL, locked ? locked : &local_locked);
lru_add_drain();
return ret;
}
/*
* faultin_vma_page_range() - populate (prefault) page tables inside the
* given VMA range readable/writable
*
* This takes care of mlocking the pages, too, if VM_LOCKED is set.
*
* @vma: target vma
* @start: start address
* @end: end address
* @write: whether to prefault readable or writable
* @locked: whether the mmap_lock is still held
*
* Returns either number of processed pages in the vma, or a negative error
* code on error (see __get_user_pages()).
*
* vma->vm_mm->mmap_lock must be held. The range must be page-aligned and
* covered by the VMA. If it's released, *@locked will be set to 0.
*/
long faultin_vma_page_range(struct vm_area_struct *vma, unsigned long start,
unsigned long end, bool write, int *locked)
{
struct mm_struct *mm = vma->vm_mm;
unsigned long nr_pages = (end - start) / PAGE_SIZE;
int gup_flags;
long ret;
VM_BUG_ON(!PAGE_ALIGNED(start));
VM_BUG_ON(!PAGE_ALIGNED(end));
VM_BUG_ON_VMA(start < vma->vm_start, vma);
VM_BUG_ON_VMA(end > vma->vm_end, vma);
mmap_assert_locked(mm);
/*
* FOLL_TOUCH: Mark page accessed and thereby young; will also mark
* the page dirty with FOLL_WRITE -- which doesn't make a
* difference with !FOLL_FORCE, because the page is writable
* in the page table.
* FOLL_HWPOISON: Return -EHWPOISON instead of -EFAULT when we hit
* a poisoned page.
* !FOLL_FORCE: Require proper access permissions.
*/
gup_flags = FOLL_TOUCH | FOLL_HWPOISON | FOLL_UNLOCKABLE;
if (write)
gup_flags |= FOLL_WRITE;
/*
* We want to report -EINVAL instead of -EFAULT for any permission
* problems or incompatible mappings.
*/
if (check_vma_flags(vma, gup_flags))
return -EINVAL;
ret = __get_user_pages(mm, start, nr_pages, gup_flags,
NULL, locked);
lru_add_drain();
return ret;
}
/*
* __mm_populate - populate and/or mlock pages within a range of address space.
*
* This is used to implement mlock() and the MAP_POPULATE / MAP_LOCKED mmap
* flags. VMAs must be already marked with the desired vm_flags, and
* mmap_lock must not be held.
*/
int __mm_populate(unsigned long start, unsigned long len, int ignore_errors)
{
struct mm_struct *mm = current->mm;
unsigned long end, nstart, nend;
struct vm_area_struct *vma = NULL;
int locked = 0;
long ret = 0;
end = start + len;
for (nstart = start; nstart < end; nstart = nend) {
/*
* We want to fault in pages for [nstart; end) address range.
* Find first corresponding VMA.
*/
if (!locked) {
locked = 1;
mmap_read_lock(mm);
vma = find_vma_intersection(mm, nstart, end);
} else if (nstart >= vma->vm_end)
vma = find_vma_intersection(mm, vma->vm_end, end);
if (!vma)
break;
/*
* Set [nstart; nend) to intersection of desired address
* range with the first VMA. Also, skip undesirable VMA types.
*/
nend = min(end, vma->vm_end);
if (vma->vm_flags & (VM_IO | VM_PFNMAP))
continue;
if (nstart < vma->vm_start)
nstart = vma->vm_start;
/*
* Now fault in a range of pages. populate_vma_page_range()
* double checks the vma flags, so that it won't mlock pages
* if the vma was already munlocked.
*/
ret = populate_vma_page_range(vma, nstart, nend, &locked);
if (ret < 0) {
if (ignore_errors) {
ret = 0;
continue; /* continue at next VMA */
}
break;
}
nend = nstart + ret * PAGE_SIZE;
ret = 0;
}
if (locked)
mmap_read_unlock(mm);
return ret; /* 0 or negative error code */
}
#else /* CONFIG_MMU */
static long __get_user_pages_locked(struct mm_struct *mm, unsigned long start,
unsigned long nr_pages, struct page **pages,
int *locked, unsigned int foll_flags)
{
struct vm_area_struct *vma;
bool must_unlock = false;
unsigned long vm_flags;
long i;
if (!nr_pages)
return 0;
/*
* The internal caller expects GUP to manage the lock internally and the
* lock must be released when this returns.
*/
if (!*locked) {
if (mmap_read_lock_killable(mm))
return -EAGAIN;
must_unlock = true;
*locked = 1;
}
/* calculate required read or write permissions.
* If FOLL_FORCE is set, we only require the "MAY" flags.
*/
vm_flags = (foll_flags & FOLL_WRITE) ?
(VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
vm_flags &= (foll_flags & FOLL_FORCE) ?
(VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
for (i = 0; i < nr_pages; i++) {
vma = find_vma(mm, start);
if (!vma)
break;
/* protect what we can, including chardevs */
if ((vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
!(vm_flags & vma->vm_flags))
break;
if (pages) {
pages[i] = virt_to_page((void *)start);
if (pages[i])
get_page(pages[i]);
}
start = (start + PAGE_SIZE) & PAGE_MASK;
}
if (must_unlock && *locked) {
mmap_read_unlock(mm);
*locked = 0;
}
return i ? : -EFAULT;
}
#endif /* !CONFIG_MMU */
/**
* fault_in_writeable - fault in userspace address range for writing
* @uaddr: start of address range
* @size: size of address range
*
* Returns the number of bytes not faulted in (like copy_to_user() and
* copy_from_user()).
*/
size_t fault_in_writeable(char __user *uaddr, size_t size)
{
char __user *start = uaddr, *end;
if (unlikely(size == 0))
return 0;
if (!user_write_access_begin(uaddr, size))
return size;
if (!PAGE_ALIGNED(uaddr)) {
unsafe_put_user(0, uaddr, out);
uaddr = (char __user *)PAGE_ALIGN((unsigned long)uaddr);
}
end = (char __user *)PAGE_ALIGN((unsigned long)start + size);
if (unlikely(end < start))
end = NULL;
while (uaddr != end) {
unsafe_put_user(0, uaddr, out);
uaddr += PAGE_SIZE;
}
out:
user_write_access_end();
if (size > uaddr - start)
return size - (uaddr - start);
return 0;
}
EXPORT_SYMBOL(fault_in_writeable);
/**
* fault_in_subpage_writeable - fault in an address range for writing
* @uaddr: start of address range
* @size: size of address range
*
* Fault in a user address range for writing while checking for permissions at
* sub-page granularity (e.g. arm64 MTE). This function should be used when
* the caller cannot guarantee forward progress of a copy_to_user() loop.
*
* Returns the number of bytes not faulted in (like copy_to_user() and
* copy_from_user()).
*/
size_t fault_in_subpage_writeable(char __user *uaddr, size_t size)
{
size_t faulted_in;
/*
* Attempt faulting in at page granularity first for page table
* permission checking. The arch-specific probe_subpage_writeable()
* functions may not check for this.
*/
faulted_in = size - fault_in_writeable(uaddr, size);
if (faulted_in)
faulted_in -= probe_subpage_writeable(uaddr, faulted_in);
return size - faulted_in;
}
EXPORT_SYMBOL(fault_in_subpage_writeable);
/*
* fault_in_safe_writeable - fault in an address range for writing
* @uaddr: start of address range
* @size: length of address range
*
* Faults in an address range for writing. This is primarily useful when we
* already know that some or all of the pages in the address range aren't in
* memory.
*
* Unlike fault_in_writeable(), this function is non-destructive.
*
* Note that we don't pin or otherwise hold the pages referenced that we fault
* in. There's no guarantee that they'll stay in memory for any duration of
* time.
*
* Returns the number of bytes not faulted in, like copy_to_user() and
* copy_from_user().
*/
size_t fault_in_safe_writeable(const char __user *uaddr, size_t size)
{
unsigned long start = (unsigned long)uaddr, end;
struct mm_struct *mm = current->mm;
bool unlocked = false;
if (unlikely(size == 0))
return 0;
end = PAGE_ALIGN(start + size);
if (end < start)
end = 0;
mmap_read_lock(mm);
do {
if (fixup_user_fault(mm, start, FAULT_FLAG_WRITE, &unlocked))
break;
start = (start + PAGE_SIZE) & PAGE_MASK;
} while (start != end);
mmap_read_unlock(mm);
if (size > (unsigned long)uaddr - start)
return size - ((unsigned long)uaddr - start);
return 0;
}
EXPORT_SYMBOL(fault_in_safe_writeable);
/**
* fault_in_readable - fault in userspace address range for reading
* @uaddr: start of user address range
* @size: size of user address range
*
* Returns the number of bytes not faulted in (like copy_to_user() and
* copy_from_user()).
*/
size_t fault_in_readable(const char __user *uaddr, size_t size)
{
const char __user *start = uaddr, *end;
volatile char c;
if (unlikely(size == 0))
return 0;
if (!user_read_access_begin(uaddr, size))
return size;
if (!PAGE_ALIGNED(uaddr)) {
unsafe_get_user(c, uaddr, out);
uaddr = (const char __user *)PAGE_ALIGN((unsigned long)uaddr);
}
end = (const char __user *)PAGE_ALIGN((unsigned long)start + size);
if (unlikely(end < start))
end = NULL;
while (uaddr != end) {
unsafe_get_user(c, uaddr, out);
uaddr += PAGE_SIZE;
}
out:
user_read_access_end();
(void)c;
if (size > uaddr - start)
return size - (uaddr - start);
return 0;
}
EXPORT_SYMBOL(fault_in_readable);
/**
* get_dump_page() - pin user page in memory while writing it to core dump
* @addr: user address
*
* Returns struct page pointer of user page pinned for dump,
* to be freed afterwards by put_page().
*
* Returns NULL on any kind of failure - a hole must then be inserted into
* the corefile, to preserve alignment with its headers; and also returns
* NULL wherever the ZERO_PAGE, or an anonymous pte_none, has been found -
* allowing a hole to be left in the corefile to save disk space.
*
* Called without mmap_lock (takes and releases the mmap_lock by itself).
*/
#ifdef CONFIG_ELF_CORE
struct page *get_dump_page(unsigned long addr)
{
struct page *page;
int locked = 0;
int ret;
ret = __get_user_pages_locked(current->mm, addr, 1, &page, &locked,
FOLL_FORCE | FOLL_DUMP | FOLL_GET);
return (ret == 1) ? page : NULL;
}
#endif /* CONFIG_ELF_CORE */
#ifdef CONFIG_MIGRATION
/*
* Returns the number of collected pages. Return value is always >= 0.
*/
static unsigned long collect_longterm_unpinnable_pages(
struct list_head *movable_page_list,
unsigned long nr_pages,
struct page **pages)
{
unsigned long i, collected = 0;
struct folio *prev_folio = NULL;
bool drain_allow = true;
for (i = 0; i < nr_pages; i++) {
struct folio *folio = page_folio(pages[i]);
if (folio == prev_folio)
continue;
prev_folio = folio;
if (folio_is_longterm_pinnable(folio))
continue;
collected++;
if (folio_is_device_coherent(folio))
continue;
if (folio_test_hugetlb(folio)) {
isolate_hugetlb(folio, movable_page_list);
continue;
}
if (!folio_test_lru(folio) && drain_allow) {
lru_add_drain_all();
drain_allow = false;
}
if (!folio_isolate_lru(folio))
continue;
list_add_tail(&folio->lru, movable_page_list);
node_stat_mod_folio(folio,
NR_ISOLATED_ANON + folio_is_file_lru(folio),
folio_nr_pages(folio));
}
return collected;
}
/*
* Unpins all pages and migrates device coherent pages and movable_page_list.
* Returns -EAGAIN if all pages were successfully migrated or -errno for failure
* (or partial success).
*/
static int migrate_longterm_unpinnable_pages(
struct list_head *movable_page_list,
unsigned long nr_pages,
struct page **pages)
{
int ret;
unsigned long i;
for (i = 0; i < nr_pages; i++) {
struct folio *folio = page_folio(pages[i]);
if (folio_is_device_coherent(folio)) {
/*
* Migration will fail if the page is pinned, so convert
* the pin on the source page to a normal reference.
*/
pages[i] = NULL;
folio_get(folio);
gup_put_folio(folio, 1, FOLL_PIN);
if (migrate_device_coherent_page(&folio->page)) {
ret = -EBUSY;
goto err;
}
continue;
}
/*
* We can't migrate pages with unexpected references, so drop
* the reference obtained by __get_user_pages_locked().
* Migrating pages have been added to movable_page_list after
* calling folio_isolate_lru() which takes a reference so the
* page won't be freed if it's migrating.
*/
unpin_user_page(pages[i]);
pages[i] = NULL;
}
if (!list_empty(movable_page_list)) {
struct migration_target_control mtc = {
.nid = NUMA_NO_NODE,
.gfp_mask = GFP_USER | __GFP_NOWARN,
};
if (migrate_pages(movable_page_list, alloc_migration_target,
NULL, (unsigned long)&mtc, MIGRATE_SYNC,
MR_LONGTERM_PIN, NULL)) {
ret = -ENOMEM;
goto err;
}
}
putback_movable_pages(movable_page_list);
return -EAGAIN;
err:
for (i = 0; i < nr_pages; i++)
if (pages[i])
unpin_user_page(pages[i]);
putback_movable_pages(movable_page_list);
return ret;
}
/*
* Check whether all pages are *allowed* to be pinned. Rather confusingly, all
* pages in the range are required to be pinned via FOLL_PIN, before calling
* this routine.
*
* If any pages in the range are not allowed to be pinned, then this routine
* will migrate those pages away, unpin all the pages in the range and return
* -EAGAIN. The caller should re-pin the entire range with FOLL_PIN and then
* call this routine again.
*
* If an error other than -EAGAIN occurs, this indicates a migration failure.
* The caller should give up, and propagate the error back up the call stack.
*
* If everything is OK and all pages in the range are allowed to be pinned, then
* this routine leaves all pages pinned and returns zero for success.
*/
static long check_and_migrate_movable_pages(unsigned long nr_pages,
struct page **pages)
{
unsigned long collected;
LIST_HEAD(movable_page_list);
collected = collect_longterm_unpinnable_pages(&movable_page_list,
nr_pages, pages);
if (!collected)
return 0;
return migrate_longterm_unpinnable_pages(&movable_page_list, nr_pages,
pages);
}
#else
static long check_and_migrate_movable_pages(unsigned long nr_pages,
struct page **pages)
{
return 0;
}
#endif /* CONFIG_MIGRATION */
/*
* __gup_longterm_locked() is a wrapper for __get_user_pages_locked which
* allows us to process the FOLL_LONGTERM flag.
*/
static long __gup_longterm_locked(struct mm_struct *mm,
unsigned long start,
unsigned long nr_pages,
struct page **pages,
int *locked,
unsigned int gup_flags)
{
unsigned int flags;
long rc, nr_pinned_pages;
if (!(gup_flags & FOLL_LONGTERM))
return __get_user_pages_locked(mm, start, nr_pages, pages,
locked, gup_flags);
flags = memalloc_pin_save();
do {
nr_pinned_pages = __get_user_pages_locked(mm, start, nr_pages,
pages, locked,
gup_flags);
if (nr_pinned_pages <= 0) {
rc = nr_pinned_pages;
break;
}
/* FOLL_LONGTERM implies FOLL_PIN */
rc = check_and_migrate_movable_pages(nr_pinned_pages, pages);
} while (rc == -EAGAIN);
memalloc_pin_restore(flags);
return rc ? rc : nr_pinned_pages;
}
/*
* Check that the given flags are valid for the exported gup/pup interface, and
* update them with the required flags that the caller must have set.
*/
static bool is_valid_gup_args(struct page **pages, int *locked,
unsigned int *gup_flags_p, unsigned int to_set)
{
unsigned int gup_flags = *gup_flags_p;
/*
* These flags not allowed to be specified externally to the gup
* interfaces:
* - FOLL_PIN/FOLL_TRIED/FOLL_FAST_ONLY are internal only
* - FOLL_REMOTE is internal only and used on follow_page()
* - FOLL_UNLOCKABLE is internal only and used if locked is !NULL
*/
if (WARN_ON_ONCE(gup_flags & (FOLL_PIN | FOLL_TRIED | FOLL_UNLOCKABLE |
FOLL_REMOTE | FOLL_FAST_ONLY)))
return false;
gup_flags |= to_set;
if (locked) {
/* At the external interface locked must be set */
if (WARN_ON_ONCE(*locked != 1))
return false;
gup_flags |= FOLL_UNLOCKABLE;
}
/* FOLL_GET and FOLL_PIN are mutually exclusive. */
if (WARN_ON_ONCE((gup_flags & (FOLL_PIN | FOLL_GET)) ==
(FOLL_PIN | FOLL_GET)))
return false;
/* LONGTERM can only be specified when pinning */
if (WARN_ON_ONCE(!(gup_flags & FOLL_PIN) && (gup_flags & FOLL_LONGTERM)))
return false;
/* Pages input must be given if using GET/PIN */
if (WARN_ON_ONCE((gup_flags & (FOLL_GET | FOLL_PIN)) && !pages))
return false;
/* We want to allow the pgmap to be hot-unplugged at all times */
if (WARN_ON_ONCE((gup_flags & FOLL_LONGTERM) &&
(gup_flags & FOLL_PCI_P2PDMA)))
return false;
*gup_flags_p = gup_flags;
return true;
}
#ifdef CONFIG_MMU
/**
* get_user_pages_remote() - pin user pages in memory
* @mm: mm_struct of target mm
* @start: starting user address
* @nr_pages: number of pages from start to pin
* @gup_flags: flags modifying lookup behaviour
* @pages: array that receives pointers to the pages pinned.
* Should be at least nr_pages long. Or NULL, if caller
* only intends to ensure the pages are faulted in.
* @locked: pointer to lock flag indicating whether lock is held and
* subsequently whether VM_FAULT_RETRY functionality can be
* utilised. Lock must initially be held.
*
* Returns either number of pages pinned (which may be less than the
* number requested), or an error. Details about the return value:
*
* -- If nr_pages is 0, returns 0.
* -- If nr_pages is >0, but no pages were pinned, returns -errno.
* -- If nr_pages is >0, and some pages were pinned, returns the number of
* pages pinned. Again, this may be less than nr_pages.
*
* The caller is responsible for releasing returned @pages, via put_page().
*
* Must be called with mmap_lock held for read or write.
*
* get_user_pages_remote walks a process's page tables and takes a reference
* to each struct page that each user address corresponds to at a given
* instant. That is, it takes the page that would be accessed if a user
* thread accesses the given user virtual address at that instant.
*
* This does not guarantee that the page exists in the user mappings when
* get_user_pages_remote returns, and there may even be a completely different
* page there in some cases (eg. if mmapped pagecache has been invalidated
* and subsequently re-faulted). However it does guarantee that the page
* won't be freed completely. And mostly callers simply care that the page
* contains data that was valid *at some point in time*. Typically, an IO
* or similar operation cannot guarantee anything stronger anyway because
* locks can't be held over the syscall boundary.
*
* If gup_flags & FOLL_WRITE == 0, the page must not be written to. If the page
* is written to, set_page_dirty (or set_page_dirty_lock, as appropriate) must
* be called after the page is finished with, and before put_page is called.
*
* get_user_pages_remote is typically used for fewer-copy IO operations,
* to get a handle on the memory by some means other than accesses
* via the user virtual addresses. The pages may be submitted for
* DMA to devices or accessed via their kernel linear mapping (via the
* kmap APIs). Care should be taken to use the correct cache flushing APIs.
*
* See also get_user_pages_fast, for performance critical applications.
*
* get_user_pages_remote should be phased out in favor of
* get_user_pages_locked|unlocked or get_user_pages_fast. Nothing
* should use get_user_pages_remote because it cannot pass
* FAULT_FLAG_ALLOW_RETRY to handle_mm_fault.
*/
long get_user_pages_remote(struct mm_struct *mm,
unsigned long start, unsigned long nr_pages,
unsigned int gup_flags, struct page **pages,
int *locked)
{
int local_locked = 1;
if (!is_valid_gup_args(pages, locked, &gup_flags,
FOLL_TOUCH | FOLL_REMOTE))
return -EINVAL;
return __get_user_pages_locked(mm, start, nr_pages, pages,
locked ? locked : &local_locked,
gup_flags);
}
EXPORT_SYMBOL(get_user_pages_remote);
#else /* CONFIG_MMU */
long get_user_pages_remote(struct mm_struct *mm,
unsigned long start, unsigned long nr_pages,
unsigned int gup_flags, struct page **pages,
int *locked)
{
return 0;
}
#endif /* !CONFIG_MMU */
/**
* get_user_pages() - pin user pages in memory
* @start: starting user address
* @nr_pages: number of pages from start to pin
* @gup_flags: flags modifying lookup behaviour
* @pages: array that receives pointers to the pages pinned.
* Should be at least nr_pages long. Or NULL, if caller
* only intends to ensure the pages are faulted in.
*
* This is the same as get_user_pages_remote(), just with a less-flexible
* calling convention where we assume that the mm being operated on belongs to
* the current task, and doesn't allow passing of a locked parameter. We also
* obviously don't pass FOLL_REMOTE in here.
*/
long get_user_pages(unsigned long start, unsigned long nr_pages,
unsigned int gup_flags, struct page **pages)
{
int locked = 1;
if (!is_valid_gup_args(pages, NULL, &gup_flags, FOLL_TOUCH))
return -EINVAL;
return __get_user_pages_locked(current->mm, start, nr_pages, pages,
&locked, gup_flags);
}
EXPORT_SYMBOL(get_user_pages);
/*
* get_user_pages_unlocked() is suitable to replace the form:
*
* mmap_read_lock(mm);
* get_user_pages(mm, ..., pages, NULL);
* mmap_read_unlock(mm);
*
* with:
*
* get_user_pages_unlocked(mm, ..., pages);
*
* It is functionally equivalent to get_user_pages_fast so
* get_user_pages_fast should be used instead if specific gup_flags
* (e.g. FOLL_FORCE) are not required.
*/
long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
struct page **pages, unsigned int gup_flags)
{
int locked = 0;
if (!is_valid_gup_args(pages, NULL, &gup_flags,
FOLL_TOUCH | FOLL_UNLOCKABLE))
return -EINVAL;
return __get_user_pages_locked(current->mm, start, nr_pages, pages,
&locked, gup_flags);
}
EXPORT_SYMBOL(get_user_pages_unlocked);
/*
* Fast GUP
*
* get_user_pages_fast attempts to pin user pages by walking the page
* tables directly and avoids taking locks. Thus the walker needs to be
* protected from page table pages being freed from under it, and should
* block any THP splits.
*
* One way to achieve this is to have the walker disable interrupts, and
* rely on IPIs from the TLB flushing code blocking before the page table
* pages are freed. This is unsuitable for architectures that do not need
* to broadcast an IPI when invalidating TLBs.
*
* Another way to achieve this is to batch up page table containing pages
* belonging to more than one mm_user, then rcu_sched a callback to free those
* pages. Disabling interrupts will allow the fast_gup walker to both block
* the rcu_sched callback, and an IPI that we broadcast for splitting THPs
* (which is a relatively rare event). The code below adopts this strategy.
*
* Before activating this code, please be aware that the following assumptions
* are currently made:
*
* *) Either MMU_GATHER_RCU_TABLE_FREE is enabled, and tlb_remove_table() is used to
* free pages containing page tables or TLB flushing requires IPI broadcast.
*
* *) ptes can be read atomically by the architecture.
*
* *) access_ok is sufficient to validate userspace address ranges.
*
* The last two assumptions can be relaxed by the addition of helper functions.
*
* This code is based heavily on the PowerPC implementation by Nick Piggin.
*/
#ifdef CONFIG_HAVE_FAST_GUP
/*
* Used in the GUP-fast path to determine whether a pin is permitted for a
* specific folio.
*
* This call assumes the caller has pinned the folio, that the lowest page table
* level still points to this folio, and that interrupts have been disabled.
*
* Writing to pinned file-backed dirty tracked folios is inherently problematic
* (see comment describing the writable_file_mapping_allowed() function). We
* therefore try to avoid the most egregious case of a long-term mapping doing
* so.
*
* This function cannot be as thorough as that one as the VMA is not available
* in the fast path, so instead we whitelist known good cases and if in doubt,
* fall back to the slow path.
*/
static bool folio_fast_pin_allowed(struct folio *folio, unsigned int flags)
{
struct address_space *mapping;
unsigned long mapping_flags;
/*
* If we aren't pinning then no problematic write can occur. A long term
* pin is the most egregious case so this is the one we disallow.
*/
if ((flags & (FOLL_PIN | FOLL_LONGTERM | FOLL_WRITE)) !=
(FOLL_PIN | FOLL_LONGTERM | FOLL_WRITE))
return true;
/* The folio is pinned, so we can safely access folio fields. */
if (WARN_ON_ONCE(folio_test_slab(folio)))
return false;
/* hugetlb mappings do not require dirty-tracking. */
if (folio_test_hugetlb(folio))
return true;
/*
* GUP-fast disables IRQs. When IRQS are disabled, RCU grace periods
* cannot proceed, which means no actions performed under RCU can
* proceed either.
*
* inodes and thus their mappings are freed under RCU, which means the
* mapping cannot be freed beneath us and thus we can safely dereference
* it.
*/
lockdep_assert_irqs_disabled();
/*
* However, there may be operations which _alter_ the mapping, so ensure
* we read it once and only once.
*/
mapping = READ_ONCE(folio->mapping);
/*
* The mapping may have been truncated, in any case we cannot determine
* if this mapping is safe - fall back to slow path to determine how to
* proceed.
*/
if (!mapping)
return false;
/* Anonymous folios pose no problem. */
mapping_flags = (unsigned long)mapping & PAGE_MAPPING_FLAGS;
if (mapping_flags)
return mapping_flags & PAGE_MAPPING_ANON;
/*
* At this point, we know the mapping is non-null and points to an
* address_space object. The only remaining whitelisted file system is
* shmem.
*/
return shmem_mapping(mapping);
}
static void __maybe_unused undo_dev_pagemap(int *nr, int nr_start,
unsigned int flags,
struct page **pages)
{
while ((*nr) - nr_start) {
struct page *page = pages[--(*nr)];
ClearPageReferenced(page);
if (flags & FOLL_PIN)
unpin_user_page(page);
else
put_page(page);
}
}
#ifdef CONFIG_ARCH_HAS_PTE_SPECIAL
/*
* Fast-gup relies on pte change detection to avoid concurrent pgtable
* operations.
*
* To pin the page, fast-gup needs to do below in order:
* (1) pin the page (by prefetching pte), then (2) check pte not changed.
*
* For the rest of pgtable operations where pgtable updates can be racy
* with fast-gup, we need to do (1) clear pte, then (2) check whether page
* is pinned.
*
* Above will work for all pte-level operations, including THP split.
*
* For THP collapse, it's a bit more complicated because fast-gup may be
* walking a pgtable page that is being freed (pte is still valid but pmd
* can be cleared already). To avoid race in such condition, we need to
* also check pmd here to make sure pmd doesn't change (corresponds to
* pmdp_collapse_flush() in the THP collapse code path).
*/
static int gup_pte_range(pmd_t pmd, pmd_t *pmdp, unsigned long addr,
unsigned long end, unsigned int flags,
struct page **pages, int *nr)
{
struct dev_pagemap *pgmap = NULL;
int nr_start = *nr, ret = 0;
pte_t *ptep, *ptem;
ptem = ptep = pte_offset_map(&pmd, addr);
if (!ptep)
return 0;
do {
pte_t pte = ptep_get_lockless(ptep);
struct page *page;
struct folio *folio;
/*
* Always fallback to ordinary GUP on PROT_NONE-mapped pages:
* pte_access_permitted() better should reject these pages
* either way: otherwise, GUP-fast might succeed in
* cases where ordinary GUP would fail due to VMA access
* permissions.
*/
if (pte_protnone(pte))
goto pte_unmap;
if (!pte_access_permitted(pte, flags & FOLL_WRITE))
goto pte_unmap;
if (pte_devmap(pte)) {
if (unlikely(flags & FOLL_LONGTERM))
goto pte_unmap;
pgmap = get_dev_pagemap(pte_pfn(pte), pgmap);
if (unlikely(!pgmap)) {
undo_dev_pagemap(nr, nr_start, flags, pages);
goto pte_unmap;
}
} else if (pte_special(pte))
goto pte_unmap;
VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
page = pte_page(pte);
folio = try_grab_folio(page, 1, flags);
if (!folio)
goto pte_unmap;
if (unlikely(folio_is_secretmem(folio))) {
gup_put_folio(folio, 1, flags);
goto pte_unmap;
}
if (unlikely(pmd_val(pmd) != pmd_val(*pmdp)) ||
unlikely(pte_val(pte) != pte_val(ptep_get(ptep)))) {
gup_put_folio(folio, 1, flags);
goto pte_unmap;
}
if (!folio_fast_pin_allowed(folio, flags)) {
gup_put_folio(folio, 1, flags);
goto pte_unmap;
}
if (!pte_write(pte) && gup_must_unshare(NULL, flags, page)) {
gup_put_folio(folio, 1, flags);
goto pte_unmap;
}
/*
* We need to make the page accessible if and only if we are
* going to access its content (the FOLL_PIN case). Please
* see Documentation/core-api/pin_user_pages.rst for
* details.
*/
if (flags & FOLL_PIN) {
ret = arch_make_page_accessible(page);
if (ret) {
gup_put_folio(folio, 1, flags);
goto pte_unmap;
}
}
folio_set_referenced(folio);
pages[*nr] = page;
(*nr)++;
} while (ptep++, addr += PAGE_SIZE, addr != end);
ret = 1;
pte_unmap:
if (pgmap)
put_dev_pagemap(pgmap);
pte_unmap(ptem);
return ret;
}
#else
/*
* If we can't determine whether or not a pte is special, then fail immediately
* for ptes. Note, we can still pin HugeTLB and THP as these are guaranteed not
* to be special.
*
* For a futex to be placed on a THP tail page, get_futex_key requires a
* get_user_pages_fast_only implementation that can pin pages. Thus it's still
* useful to have gup_huge_pmd even if we can't operate on ptes.
*/
static int gup_pte_range(pmd_t pmd, pmd_t *pmdp, unsigned long addr,
unsigned long end, unsigned int flags,
struct page **pages, int *nr)
{
return 0;
}
#endif /* CONFIG_ARCH_HAS_PTE_SPECIAL */
#if defined(CONFIG_ARCH_HAS_PTE_DEVMAP) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
static int __gup_device_huge(unsigned long pfn, unsigned long addr,
unsigned long end, unsigned int flags,
struct page **pages, int *nr)
{
int nr_start = *nr;
struct dev_pagemap *pgmap = NULL;
do {
struct page *page = pfn_to_page(pfn);
pgmap = get_dev_pagemap(pfn, pgmap);
if (unlikely(!pgmap)) {
undo_dev_pagemap(nr, nr_start, flags, pages);
break;
}
if (!(flags & FOLL_PCI_P2PDMA) && is_pci_p2pdma_page(page)) {
undo_dev_pagemap(nr, nr_start, flags, pages);
break;
}
SetPageReferenced(page);
pages[*nr] = page;
if (unlikely(try_grab_page(page, flags))) {
undo_dev_pagemap(nr, nr_start, flags, pages);
break;
}
(*nr)++;
pfn++;
} while (addr += PAGE_SIZE, addr != end);
put_dev_pagemap(pgmap);
return addr == end;
}
static int __gup_device_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr,
unsigned long end, unsigned int flags,
struct page **pages, int *nr)
{
unsigned long fault_pfn;
int nr_start = *nr;
fault_pfn = pmd_pfn(orig) + ((addr & ~PMD_MASK) >> PAGE_SHIFT);
if (!__gup_device_huge(fault_pfn, addr, end, flags, pages, nr))
return 0;
if (unlikely(pmd_val(orig) != pmd_val(*pmdp))) {
undo_dev_pagemap(nr, nr_start, flags, pages);
return 0;
}
return 1;
}
static int __gup_device_huge_pud(pud_t orig, pud_t *pudp, unsigned long addr,
unsigned long end, unsigned int flags,
struct page **pages, int *nr)
{
unsigned long fault_pfn;
int nr_start = *nr;
fault_pfn = pud_pfn(orig) + ((addr & ~PUD_MASK) >> PAGE_SHIFT);
if (!__gup_device_huge(fault_pfn, addr, end, flags, pages, nr))
return 0;
if (unlikely(pud_val(orig) != pud_val(*pudp))) {
undo_dev_pagemap(nr, nr_start, flags, pages);
return 0;
}
return 1;
}
#else
static int __gup_device_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr,
unsigned long end, unsigned int flags,
struct page **pages, int *nr)
{
BUILD_BUG();
return 0;
}
static int __gup_device_huge_pud(pud_t pud, pud_t *pudp, unsigned long addr,
unsigned long end, unsigned int flags,
struct page **pages, int *nr)
{
BUILD_BUG();
return 0;
}
#endif
static int record_subpages(struct page *page, unsigned long addr,
unsigned long end, struct page **pages)
{
int nr;
for (nr = 0; addr != end; nr++, addr += PAGE_SIZE)
pages[nr] = nth_page(page, nr);
return nr;
}
#ifdef CONFIG_ARCH_HAS_HUGEPD
static unsigned long hugepte_addr_end(unsigned long addr, unsigned long end,
unsigned long sz)
{
unsigned long __boundary = (addr + sz) & ~(sz-1);
return (__boundary - 1 < end - 1) ? __boundary : end;
}
static int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
unsigned long end, unsigned int flags,
struct page **pages, int *nr)
{
unsigned long pte_end;
struct page *page;
struct folio *folio;
pte_t pte;
int refs;
pte_end = (addr + sz) & ~(sz-1);
if (pte_end < end)
end = pte_end;
pte = huge_ptep_get(ptep);
if (!pte_access_permitted(pte, flags & FOLL_WRITE))
return 0;
/* hugepages are never "special" */
VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
page = nth_page(pte_page(pte), (addr & (sz - 1)) >> PAGE_SHIFT);
refs = record_subpages(page, addr, end, pages + *nr);
folio = try_grab_folio(page, refs, flags);
if (!folio)
return 0;
if (unlikely(pte_val(pte) != pte_val(ptep_get(ptep)))) {
gup_put_folio(folio, refs, flags);
return 0;
}
if (!folio_fast_pin_allowed(folio, flags)) {
gup_put_folio(folio, refs, flags);
return 0;
}
if (!pte_write(pte) && gup_must_unshare(NULL, flags, &folio->page)) {
gup_put_folio(folio, refs, flags);
return 0;
}
*nr += refs;
folio_set_referenced(folio);
return 1;
}
static int gup_huge_pd(hugepd_t hugepd, unsigned long addr,
unsigned int pdshift, unsigned long end, unsigned int flags,
struct page **pages, int *nr)
{
pte_t *ptep;
unsigned long sz = 1UL << hugepd_shift(hugepd);
unsigned long next;
ptep = hugepte_offset(hugepd, addr, pdshift);
do {
next = hugepte_addr_end(addr, end, sz);
if (!gup_hugepte(ptep, sz, addr, end, flags, pages, nr))
return 0;
} while (ptep++, addr = next, addr != end);
return 1;
}
#else
static inline int gup_huge_pd(hugepd_t hugepd, unsigned long addr,
unsigned int pdshift, unsigned long end, unsigned int flags,
struct page **pages, int *nr)
{
return 0;
}
#endif /* CONFIG_ARCH_HAS_HUGEPD */
static int gup_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr,
unsigned long end, unsigned int flags,
struct page **pages, int *nr)
{
struct page *page;
struct folio *folio;
int refs;
if (!pmd_access_permitted(orig, flags & FOLL_WRITE))
return 0;
if (pmd_devmap(orig)) {
if (unlikely(flags & FOLL_LONGTERM))
return 0;
return __gup_device_huge_pmd(orig, pmdp, addr, end, flags,
pages, nr);
}
page = nth_page(pmd_page(orig), (addr & ~PMD_MASK) >> PAGE_SHIFT);
refs = record_subpages(page, addr, end, pages + *nr);
folio = try_grab_folio(page, refs, flags);
if (!folio)
return 0;
if (unlikely(pmd_val(orig) != pmd_val(*pmdp))) {
gup_put_folio(folio, refs, flags);
return 0;
}
if (!folio_fast_pin_allowed(folio, flags)) {
gup_put_folio(folio, refs, flags);
return 0;
}
if (!pmd_write(orig) && gup_must_unshare(NULL, flags, &folio->page)) {
gup_put_folio(folio, refs, flags);
return 0;
}
*nr += refs;
folio_set_referenced(folio);
return 1;
}
static int gup_huge_pud(pud_t orig, pud_t *pudp, unsigned long addr,
unsigned long end, unsigned int flags,
struct page **pages, int *nr)
{
struct page *page;
struct folio *folio;
int refs;
if (!pud_access_permitted(orig, flags & FOLL_WRITE))
return 0;
if (pud_devmap(orig)) {
if (unlikely(flags & FOLL_LONGTERM))
return 0;
return __gup_device_huge_pud(orig, pudp, addr, end, flags,
pages, nr);
}
page = nth_page(pud_page(orig), (addr & ~PUD_MASK) >> PAGE_SHIFT);
refs = record_subpages(page, addr, end, pages + *nr);
folio = try_grab_folio(page, refs, flags);
if (!folio)
return 0;
if (unlikely(pud_val(orig) != pud_val(*pudp))) {
gup_put_folio(folio, refs, flags);
return 0;
}
if (!folio_fast_pin_allowed(folio, flags)) {
gup_put_folio(folio, refs, flags);
return 0;
}
if (!pud_write(orig) && gup_must_unshare(NULL, flags, &folio->page)) {
gup_put_folio(folio, refs, flags);
return 0;
}
*nr += refs;
folio_set_referenced(folio);
return 1;
}
static int gup_huge_pgd(pgd_t orig, pgd_t *pgdp, unsigned long addr,
unsigned long end, unsigned int flags,
struct page **pages, int *nr)
{
int refs;
struct page *page;
struct folio *folio;
if (!pgd_access_permitted(orig, flags & FOLL_WRITE))
return 0;
BUILD_BUG_ON(pgd_devmap(orig));
page = nth_page(pgd_page(orig), (addr & ~PGDIR_MASK) >> PAGE_SHIFT);
refs = record_subpages(page, addr, end, pages + *nr);
folio = try_grab_folio(page, refs, flags);
if (!folio)
return 0;
if (unlikely(pgd_val(orig) != pgd_val(*pgdp))) {
gup_put_folio(folio, refs, flags);
return 0;
}
if (!pgd_write(orig) && gup_must_unshare(NULL, flags, &folio->page)) {
gup_put_folio(folio, refs, flags);
return 0;
}
if (!folio_fast_pin_allowed(folio, flags)) {
gup_put_folio(folio, refs, flags);
return 0;
}
*nr += refs;
folio_set_referenced(folio);
return 1;
}
static int gup_pmd_range(pud_t *pudp, pud_t pud, unsigned long addr, unsigned long end,
unsigned int flags, struct page **pages, int *nr)
{
unsigned long next;
pmd_t *pmdp;
pmdp = pmd_offset_lockless(pudp, pud, addr);
do {
pmd_t pmd = pmdp_get_lockless(pmdp);
next = pmd_addr_end(addr, end);
if (!pmd_present(pmd))
return 0;
if (unlikely(pmd_trans_huge(pmd) || pmd_huge(pmd) ||
pmd_devmap(pmd))) {
/* See gup_pte_range() */
if (pmd_protnone(pmd))
return 0;
if (!gup_huge_pmd(pmd, pmdp, addr, next, flags,
pages, nr))
return 0;
} else if (unlikely(is_hugepd(__hugepd(pmd_val(pmd))))) {
/*
* architecture have different format for hugetlbfs
* pmd format and THP pmd format
*/
if (!gup_huge_pd(__hugepd(pmd_val(pmd)), addr,
PMD_SHIFT, next, flags, pages, nr))
return 0;
} else if (!gup_pte_range(pmd, pmdp, addr, next, flags, pages, nr))
return 0;
} while (pmdp++, addr = next, addr != end);
return 1;
}
static int gup_pud_range(p4d_t *p4dp, p4d_t p4d, unsigned long addr, unsigned long end,
unsigned int flags, struct page **pages, int *nr)
{
unsigned long next;
pud_t *pudp;
pudp = pud_offset_lockless(p4dp, p4d, addr);
do {
pud_t pud = READ_ONCE(*pudp);
next = pud_addr_end(addr, end);
if (unlikely(!pud_present(pud)))
return 0;
if (unlikely(pud_huge(pud) || pud_devmap(pud))) {
if (!gup_huge_pud(pud, pudp, addr, next, flags,
pages, nr))
return 0;
} else if (unlikely(is_hugepd(__hugepd(pud_val(pud))))) {
if (!gup_huge_pd(__hugepd(pud_val(pud)), addr,
PUD_SHIFT, next, flags, pages, nr))
return 0;
} else if (!gup_pmd_range(pudp, pud, addr, next, flags, pages, nr))
return 0;
} while (pudp++, addr = next, addr != end);
return 1;
}
static int gup_p4d_range(pgd_t *pgdp, pgd_t pgd, unsigned long addr, unsigned long end,
unsigned int flags, struct page **pages, int *nr)
{
unsigned long next;
p4d_t *p4dp;
p4dp = p4d_offset_lockless(pgdp, pgd, addr);
do {
p4d_t p4d = READ_ONCE(*p4dp);
next = p4d_addr_end(addr, end);
if (p4d_none(p4d))
return 0;
BUILD_BUG_ON(p4d_huge(p4d));
if (unlikely(is_hugepd(__hugepd(p4d_val(p4d))))) {
if (!gup_huge_pd(__hugepd(p4d_val(p4d)), addr,
P4D_SHIFT, next, flags, pages, nr))
return 0;
} else if (!gup_pud_range(p4dp, p4d, addr, next, flags, pages, nr))
return 0;
} while (p4dp++, addr = next, addr != end);
return 1;
}
static void gup_pgd_range(unsigned long addr, unsigned long end,
unsigned int flags, struct page **pages, int *nr)
{
unsigned long next;
pgd_t *pgdp;
pgdp = pgd_offset(current->mm, addr);
do {
pgd_t pgd = READ_ONCE(*pgdp);
next = pgd_addr_end(addr, end);
if (pgd_none(pgd))
return;
if (unlikely(pgd_huge(pgd))) {
if (!gup_huge_pgd(pgd, pgdp, addr, next, flags,
pages, nr))
return;
} else if (unlikely(is_hugepd(__hugepd(pgd_val(pgd))))) {
if (!gup_huge_pd(__hugepd(pgd_val(pgd)), addr,
PGDIR_SHIFT, next, flags, pages, nr))
return;
} else if (!gup_p4d_range(pgdp, pgd, addr, next, flags, pages, nr))
return;
} while (pgdp++, addr = next, addr != end);
}
#else
static inline void gup_pgd_range(unsigned long addr, unsigned long end,
unsigned int flags, struct page **pages, int *nr)
{
}
#endif /* CONFIG_HAVE_FAST_GUP */
#ifndef gup_fast_permitted
/*
* Check if it's allowed to use get_user_pages_fast_only() for the range, or
* we need to fall back to the slow version:
*/
static bool gup_fast_permitted(unsigned long start, unsigned long end)
{
return true;
}
#endif
static unsigned long lockless_pages_from_mm(unsigned long start,
unsigned long end,
unsigned int gup_flags,
struct page **pages)
{
unsigned long flags;
int nr_pinned = 0;
unsigned seq;
if (!IS_ENABLED(CONFIG_HAVE_FAST_GUP) ||
!gup_fast_permitted(start, end))
return 0;
if (gup_flags & FOLL_PIN) {
seq = raw_read_seqcount(¤t->mm->write_protect_seq);
if (seq & 1)
return 0;
}
/*
* Disable interrupts. The nested form is used, in order to allow full,
* general purpose use of this routine.
*
* With interrupts disabled, we block page table pages from being freed
* from under us. See struct mmu_table_batch comments in
* include/asm-generic/tlb.h for more details.
*
* We do not adopt an rcu_read_lock() here as we also want to block IPIs
* that come from THPs splitting.
*/
local_irq_save(flags);
gup_pgd_range(start, end, gup_flags, pages, &nr_pinned);
local_irq_restore(flags);
/*
* When pinning pages for DMA there could be a concurrent write protect
* from fork() via copy_page_range(), in this case always fail fast GUP.
*/
if (gup_flags & FOLL_PIN) {
if (read_seqcount_retry(¤t->mm->write_protect_seq, seq)) {
unpin_user_pages_lockless(pages, nr_pinned);
return 0;
} else {
sanity_check_pinned_pages(pages, nr_pinned);
}
}
return nr_pinned;
}
static int internal_get_user_pages_fast(unsigned long start,
unsigned long nr_pages,
unsigned int gup_flags,
struct page **pages)
{
unsigned long len, end;
unsigned long nr_pinned;
int locked = 0;
int ret;
if (WARN_ON_ONCE(gup_flags & ~(FOLL_WRITE | FOLL_LONGTERM |
FOLL_FORCE | FOLL_PIN | FOLL_GET |
FOLL_FAST_ONLY | FOLL_NOFAULT |
FOLL_PCI_P2PDMA | FOLL_HONOR_NUMA_FAULT)))
return -EINVAL;
if (gup_flags & FOLL_PIN)
mm_set_has_pinned_flag(¤t->mm->flags);
if (!(gup_flags & FOLL_FAST_ONLY))
might_lock_read(¤t->mm->mmap_lock);
start = untagged_addr(start) & PAGE_MASK;
len = nr_pages << PAGE_SHIFT;
if (check_add_overflow(start, len, &end))
return -EOVERFLOW;
if (end > TASK_SIZE_MAX)
return -EFAULT;
if (unlikely(!access_ok((void __user *)start, len)))
return -EFAULT;
nr_pinned = lockless_pages_from_mm(start, end, gup_flags, pages);
if (nr_pinned == nr_pages || gup_flags & FOLL_FAST_ONLY)
return nr_pinned;
/* Slow path: try to get the remaining pages with get_user_pages */
start += nr_pinned << PAGE_SHIFT;
pages += nr_pinned;
ret = __gup_longterm_locked(current->mm, start, nr_pages - nr_pinned,
pages, &locked,
gup_flags | FOLL_TOUCH | FOLL_UNLOCKABLE);
if (ret < 0) {
/*
* The caller has to unpin the pages we already pinned so
* returning -errno is not an option
*/
if (nr_pinned)
return nr_pinned;
return ret;
}
return ret + nr_pinned;
}
/**
* get_user_pages_fast_only() - pin user pages in memory
* @start: starting user address
* @nr_pages: number of pages from start to pin
* @gup_flags: flags modifying pin behaviour
* @pages: array that receives pointers to the pages pinned.
* Should be at least nr_pages long.
*
* Like get_user_pages_fast() except it's IRQ-safe in that it won't fall back to
* the regular GUP.
*
* If the architecture does not support this function, simply return with no
* pages pinned.
*
* Careful, careful! COW breaking can go either way, so a non-write
* access can get ambiguous page results. If you call this function without
* 'write' set, you'd better be sure that you're ok with that ambiguity.
*/
int get_user_pages_fast_only(unsigned long start, int nr_pages,
unsigned int gup_flags, struct page **pages)
{
/*
* Internally (within mm/gup.c), gup fast variants must set FOLL_GET,
* because gup fast is always a "pin with a +1 page refcount" request.
*
* FOLL_FAST_ONLY is required in order to match the API description of
* this routine: no fall back to regular ("slow") GUP.
*/
if (!is_valid_gup_args(pages, NULL, &gup_flags,
FOLL_GET | FOLL_FAST_ONLY))
return -EINVAL;
return internal_get_user_pages_fast(start, nr_pages, gup_flags, pages);
}
EXPORT_SYMBOL_GPL(get_user_pages_fast_only);
/**
* get_user_pages_fast() - pin user pages in memory
* @start: starting user address
* @nr_pages: number of pages from start to pin
* @gup_flags: flags modifying pin behaviour
* @pages: array that receives pointers to the pages pinned.
* Should be at least nr_pages long.
*
* Attempt to pin user pages in memory without taking mm->mmap_lock.
* If not successful, it will fall back to taking the lock and
* calling get_user_pages().
*
* Returns number of pages pinned. This may be fewer than the number requested.
* If nr_pages is 0 or negative, returns 0. If no pages were pinned, returns
* -errno.
*/
int get_user_pages_fast(unsigned long start, int nr_pages,
unsigned int gup_flags, struct page **pages)
{
/*
* The caller may or may not have explicitly set FOLL_GET; either way is
* OK. However, internally (within mm/gup.c), gup fast variants must set
* FOLL_GET, because gup fast is always a "pin with a +1 page refcount"
* request.
*/
if (!is_valid_gup_args(pages, NULL, &gup_flags, FOLL_GET))
return -EINVAL;
return internal_get_user_pages_fast(start, nr_pages, gup_flags, pages);
}
EXPORT_SYMBOL_GPL(get_user_pages_fast);
/**
* pin_user_pages_fast() - pin user pages in memory without taking locks
*
* @start: starting user address
* @nr_pages: number of pages from start to pin
* @gup_flags: flags modifying pin behaviour
* @pages: array that receives pointers to the pages pinned.
* Should be at least nr_pages long.
*
* Nearly the same as get_user_pages_fast(), except that FOLL_PIN is set. See
* get_user_pages_fast() for documentation on the function arguments, because
* the arguments here are identical.
*
* FOLL_PIN means that the pages must be released via unpin_user_page(). Please
* see Documentation/core-api/pin_user_pages.rst for further details.
*
* Note that if a zero_page is amongst the returned pages, it will not have
* pins in it and unpin_user_page() will not remove pins from it.
*/
int pin_user_pages_fast(unsigned long start, int nr_pages,
unsigned int gup_flags, struct page **pages)
{
if (!is_valid_gup_args(pages, NULL, &gup_flags, FOLL_PIN))
return -EINVAL;
return internal_get_user_pages_fast(start, nr_pages, gup_flags, pages);
}
EXPORT_SYMBOL_GPL(pin_user_pages_fast);
/**
* pin_user_pages_remote() - pin pages of a remote process
*
* @mm: mm_struct of target mm
* @start: starting user address
* @nr_pages: number of pages from start to pin
* @gup_flags: flags modifying lookup behaviour
* @pages: array that receives pointers to the pages pinned.
* Should be at least nr_pages long.
* @locked: pointer to lock flag indicating whether lock is held and
* subsequently whether VM_FAULT_RETRY functionality can be
* utilised. Lock must initially be held.
*
* Nearly the same as get_user_pages_remote(), except that FOLL_PIN is set. See
* get_user_pages_remote() for documentation on the function arguments, because
* the arguments here are identical.
*
* FOLL_PIN means that the pages must be released via unpin_user_page(). Please
* see Documentation/core-api/pin_user_pages.rst for details.
*
* Note that if a zero_page is amongst the returned pages, it will not have
* pins in it and unpin_user_page*() will not remove pins from it.
*/
long pin_user_pages_remote(struct mm_struct *mm,
unsigned long start, unsigned long nr_pages,
unsigned int gup_flags, struct page **pages,
int *locked)
{
int local_locked = 1;
if (!is_valid_gup_args(pages, locked, &gup_flags,
FOLL_PIN | FOLL_TOUCH | FOLL_REMOTE))
return 0;
return __gup_longterm_locked(mm, start, nr_pages, pages,
locked ? locked : &local_locked,
gup_flags);
}
EXPORT_SYMBOL(pin_user_pages_remote);
/**
* pin_user_pages() - pin user pages in memory for use by other devices
*
* @start: starting user address
* @nr_pages: number of pages from start to pin
* @gup_flags: flags modifying lookup behaviour
* @pages: array that receives pointers to the pages pinned.
* Should be at least nr_pages long.
*
* Nearly the same as get_user_pages(), except that FOLL_TOUCH is not set, and
* FOLL_PIN is set.
*
* FOLL_PIN means that the pages must be released via unpin_user_page(). Please
* see Documentation/core-api/pin_user_pages.rst for details.
*
* Note that if a zero_page is amongst the returned pages, it will not have
* pins in it and unpin_user_page*() will not remove pins from it.
*/
long pin_user_pages(unsigned long start, unsigned long nr_pages,
unsigned int gup_flags, struct page **pages)
{
int locked = 1;
if (!is_valid_gup_args(pages, NULL, &gup_flags, FOLL_PIN))
return 0;
return __gup_longterm_locked(current->mm, start, nr_pages,
pages, &locked, gup_flags);
}
EXPORT_SYMBOL(pin_user_pages);
/*
* pin_user_pages_unlocked() is the FOLL_PIN variant of
* get_user_pages_unlocked(). Behavior is the same, except that this one sets
* FOLL_PIN and rejects FOLL_GET.
*
* Note that if a zero_page is amongst the returned pages, it will not have
* pins in it and unpin_user_page*() will not remove pins from it.
*/
long pin_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
struct page **pages, unsigned int gup_flags)
{
int locked = 0;
if (!is_valid_gup_args(pages, NULL, &gup_flags,
FOLL_PIN | FOLL_TOUCH | FOLL_UNLOCKABLE))
return 0;
return __gup_longterm_locked(current->mm, start, nr_pages, pages,
&locked, gup_flags);
}
EXPORT_SYMBOL(pin_user_pages_unlocked);
| linux-master | mm/gup.c |
// SPDX-License-Identifier: GPL-2.0-or-later
/* memcontrol.c - Memory Controller
*
* Copyright IBM Corporation, 2007
* Author Balbir Singh <[email protected]>
*
* Copyright 2007 OpenVZ SWsoft Inc
* Author: Pavel Emelianov <[email protected]>
*
* Memory thresholds
* Copyright (C) 2009 Nokia Corporation
* Author: Kirill A. Shutemov
*
* Kernel Memory Controller
* Copyright (C) 2012 Parallels Inc. and Google Inc.
* Authors: Glauber Costa and Suleiman Souhlal
*
* Native page reclaim
* Charge lifetime sanitation
* Lockless page tracking & accounting
* Unified hierarchy configuration model
* Copyright (C) 2015 Red Hat, Inc., Johannes Weiner
*
* Per memcg lru locking
* Copyright (C) 2020 Alibaba, Inc, Alex Shi
*/
#include <linux/page_counter.h>
#include <linux/memcontrol.h>
#include <linux/cgroup.h>
#include <linux/pagewalk.h>
#include <linux/sched/mm.h>
#include <linux/shmem_fs.h>
#include <linux/hugetlb.h>
#include <linux/pagemap.h>
#include <linux/vm_event_item.h>
#include <linux/smp.h>
#include <linux/page-flags.h>
#include <linux/backing-dev.h>
#include <linux/bit_spinlock.h>
#include <linux/rcupdate.h>
#include <linux/limits.h>
#include <linux/export.h>
#include <linux/mutex.h>
#include <linux/rbtree.h>
#include <linux/slab.h>
#include <linux/swap.h>
#include <linux/swapops.h>
#include <linux/spinlock.h>
#include <linux/eventfd.h>
#include <linux/poll.h>
#include <linux/sort.h>
#include <linux/fs.h>
#include <linux/seq_file.h>
#include <linux/vmpressure.h>
#include <linux/memremap.h>
#include <linux/mm_inline.h>
#include <linux/swap_cgroup.h>
#include <linux/cpu.h>
#include <linux/oom.h>
#include <linux/lockdep.h>
#include <linux/file.h>
#include <linux/resume_user_mode.h>
#include <linux/psi.h>
#include <linux/seq_buf.h>
#include <linux/sched/isolation.h>
#include "internal.h"
#include <net/sock.h>
#include <net/ip.h>
#include "slab.h"
#include "swap.h"
#include <linux/uaccess.h>
#include <trace/events/vmscan.h>
struct cgroup_subsys memory_cgrp_subsys __read_mostly;
EXPORT_SYMBOL(memory_cgrp_subsys);
struct mem_cgroup *root_mem_cgroup __read_mostly;
/* Active memory cgroup to use from an interrupt context */
DEFINE_PER_CPU(struct mem_cgroup *, int_active_memcg);
EXPORT_PER_CPU_SYMBOL_GPL(int_active_memcg);
/* Socket memory accounting disabled? */
static bool cgroup_memory_nosocket __ro_after_init;
/* Kernel memory accounting disabled? */
static bool cgroup_memory_nokmem __ro_after_init;
/* BPF memory accounting disabled? */
static bool cgroup_memory_nobpf __ro_after_init;
#ifdef CONFIG_CGROUP_WRITEBACK
static DECLARE_WAIT_QUEUE_HEAD(memcg_cgwb_frn_waitq);
#endif
/* Whether legacy memory+swap accounting is active */
static bool do_memsw_account(void)
{
return !cgroup_subsys_on_dfl(memory_cgrp_subsys);
}
#define THRESHOLDS_EVENTS_TARGET 128
#define SOFTLIMIT_EVENTS_TARGET 1024
/*
* Cgroups above their limits are maintained in a RB-Tree, independent of
* their hierarchy representation
*/
struct mem_cgroup_tree_per_node {
struct rb_root rb_root;
struct rb_node *rb_rightmost;
spinlock_t lock;
};
struct mem_cgroup_tree {
struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES];
};
static struct mem_cgroup_tree soft_limit_tree __read_mostly;
/* for OOM */
struct mem_cgroup_eventfd_list {
struct list_head list;
struct eventfd_ctx *eventfd;
};
/*
* cgroup_event represents events which userspace want to receive.
*/
struct mem_cgroup_event {
/*
* memcg which the event belongs to.
*/
struct mem_cgroup *memcg;
/*
* eventfd to signal userspace about the event.
*/
struct eventfd_ctx *eventfd;
/*
* Each of these stored in a list by the cgroup.
*/
struct list_head list;
/*
* register_event() callback will be used to add new userspace
* waiter for changes related to this event. Use eventfd_signal()
* on eventfd to send notification to userspace.
*/
int (*register_event)(struct mem_cgroup *memcg,
struct eventfd_ctx *eventfd, const char *args);
/*
* unregister_event() callback will be called when userspace closes
* the eventfd or on cgroup removing. This callback must be set,
* if you want provide notification functionality.
*/
void (*unregister_event)(struct mem_cgroup *memcg,
struct eventfd_ctx *eventfd);
/*
* All fields below needed to unregister event when
* userspace closes eventfd.
*/
poll_table pt;
wait_queue_head_t *wqh;
wait_queue_entry_t wait;
struct work_struct remove;
};
static void mem_cgroup_threshold(struct mem_cgroup *memcg);
static void mem_cgroup_oom_notify(struct mem_cgroup *memcg);
/* Stuffs for move charges at task migration. */
/*
* Types of charges to be moved.
*/
#define MOVE_ANON 0x1U
#define MOVE_FILE 0x2U
#define MOVE_MASK (MOVE_ANON | MOVE_FILE)
/* "mc" and its members are protected by cgroup_mutex */
static struct move_charge_struct {
spinlock_t lock; /* for from, to */
struct mm_struct *mm;
struct mem_cgroup *from;
struct mem_cgroup *to;
unsigned long flags;
unsigned long precharge;
unsigned long moved_charge;
unsigned long moved_swap;
struct task_struct *moving_task; /* a task moving charges */
wait_queue_head_t waitq; /* a waitq for other context */
} mc = {
.lock = __SPIN_LOCK_UNLOCKED(mc.lock),
.waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq),
};
/*
* Maximum loops in mem_cgroup_soft_reclaim(), used for soft
* limit reclaim to prevent infinite loops, if they ever occur.
*/
#define MEM_CGROUP_MAX_RECLAIM_LOOPS 100
#define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2
/* for encoding cft->private value on file */
enum res_type {
_MEM,
_MEMSWAP,
_KMEM,
_TCP,
};
#define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val))
#define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff)
#define MEMFILE_ATTR(val) ((val) & 0xffff)
/*
* Iteration constructs for visiting all cgroups (under a tree). If
* loops are exited prematurely (break), mem_cgroup_iter_break() must
* be used for reference counting.
*/
#define for_each_mem_cgroup_tree(iter, root) \
for (iter = mem_cgroup_iter(root, NULL, NULL); \
iter != NULL; \
iter = mem_cgroup_iter(root, iter, NULL))
#define for_each_mem_cgroup(iter) \
for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
iter != NULL; \
iter = mem_cgroup_iter(NULL, iter, NULL))
static inline bool task_is_dying(void)
{
return tsk_is_oom_victim(current) || fatal_signal_pending(current) ||
(current->flags & PF_EXITING);
}
/* Some nice accessors for the vmpressure. */
struct vmpressure *memcg_to_vmpressure(struct mem_cgroup *memcg)
{
if (!memcg)
memcg = root_mem_cgroup;
return &memcg->vmpressure;
}
struct mem_cgroup *vmpressure_to_memcg(struct vmpressure *vmpr)
{
return container_of(vmpr, struct mem_cgroup, vmpressure);
}
#ifdef CONFIG_MEMCG_KMEM
static DEFINE_SPINLOCK(objcg_lock);
bool mem_cgroup_kmem_disabled(void)
{
return cgroup_memory_nokmem;
}
static void obj_cgroup_uncharge_pages(struct obj_cgroup *objcg,
unsigned int nr_pages);
static void obj_cgroup_release(struct percpu_ref *ref)
{
struct obj_cgroup *objcg = container_of(ref, struct obj_cgroup, refcnt);
unsigned int nr_bytes;
unsigned int nr_pages;
unsigned long flags;
/*
* At this point all allocated objects are freed, and
* objcg->nr_charged_bytes can't have an arbitrary byte value.
* However, it can be PAGE_SIZE or (x * PAGE_SIZE).
*
* The following sequence can lead to it:
* 1) CPU0: objcg == stock->cached_objcg
* 2) CPU1: we do a small allocation (e.g. 92 bytes),
* PAGE_SIZE bytes are charged
* 3) CPU1: a process from another memcg is allocating something,
* the stock if flushed,
* objcg->nr_charged_bytes = PAGE_SIZE - 92
* 5) CPU0: we do release this object,
* 92 bytes are added to stock->nr_bytes
* 6) CPU0: stock is flushed,
* 92 bytes are added to objcg->nr_charged_bytes
*
* In the result, nr_charged_bytes == PAGE_SIZE.
* This page will be uncharged in obj_cgroup_release().
*/
nr_bytes = atomic_read(&objcg->nr_charged_bytes);
WARN_ON_ONCE(nr_bytes & (PAGE_SIZE - 1));
nr_pages = nr_bytes >> PAGE_SHIFT;
if (nr_pages)
obj_cgroup_uncharge_pages(objcg, nr_pages);
spin_lock_irqsave(&objcg_lock, flags);
list_del(&objcg->list);
spin_unlock_irqrestore(&objcg_lock, flags);
percpu_ref_exit(ref);
kfree_rcu(objcg, rcu);
}
static struct obj_cgroup *obj_cgroup_alloc(void)
{
struct obj_cgroup *objcg;
int ret;
objcg = kzalloc(sizeof(struct obj_cgroup), GFP_KERNEL);
if (!objcg)
return NULL;
ret = percpu_ref_init(&objcg->refcnt, obj_cgroup_release, 0,
GFP_KERNEL);
if (ret) {
kfree(objcg);
return NULL;
}
INIT_LIST_HEAD(&objcg->list);
return objcg;
}
static void memcg_reparent_objcgs(struct mem_cgroup *memcg,
struct mem_cgroup *parent)
{
struct obj_cgroup *objcg, *iter;
objcg = rcu_replace_pointer(memcg->objcg, NULL, true);
spin_lock_irq(&objcg_lock);
/* 1) Ready to reparent active objcg. */
list_add(&objcg->list, &memcg->objcg_list);
/* 2) Reparent active objcg and already reparented objcgs to parent. */
list_for_each_entry(iter, &memcg->objcg_list, list)
WRITE_ONCE(iter->memcg, parent);
/* 3) Move already reparented objcgs to the parent's list */
list_splice(&memcg->objcg_list, &parent->objcg_list);
spin_unlock_irq(&objcg_lock);
percpu_ref_kill(&objcg->refcnt);
}
/*
* A lot of the calls to the cache allocation functions are expected to be
* inlined by the compiler. Since the calls to memcg_slab_pre_alloc_hook() are
* conditional to this static branch, we'll have to allow modules that does
* kmem_cache_alloc and the such to see this symbol as well
*/
DEFINE_STATIC_KEY_FALSE(memcg_kmem_online_key);
EXPORT_SYMBOL(memcg_kmem_online_key);
DEFINE_STATIC_KEY_FALSE(memcg_bpf_enabled_key);
EXPORT_SYMBOL(memcg_bpf_enabled_key);
#endif
/**
* mem_cgroup_css_from_folio - css of the memcg associated with a folio
* @folio: folio of interest
*
* If memcg is bound to the default hierarchy, css of the memcg associated
* with @folio is returned. The returned css remains associated with @folio
* until it is released.
*
* If memcg is bound to a traditional hierarchy, the css of root_mem_cgroup
* is returned.
*/
struct cgroup_subsys_state *mem_cgroup_css_from_folio(struct folio *folio)
{
struct mem_cgroup *memcg = folio_memcg(folio);
if (!memcg || !cgroup_subsys_on_dfl(memory_cgrp_subsys))
memcg = root_mem_cgroup;
return &memcg->css;
}
/**
* page_cgroup_ino - return inode number of the memcg a page is charged to
* @page: the page
*
* Look up the closest online ancestor of the memory cgroup @page is charged to
* and return its inode number or 0 if @page is not charged to any cgroup. It
* is safe to call this function without holding a reference to @page.
*
* Note, this function is inherently racy, because there is nothing to prevent
* the cgroup inode from getting torn down and potentially reallocated a moment
* after page_cgroup_ino() returns, so it only should be used by callers that
* do not care (such as procfs interfaces).
*/
ino_t page_cgroup_ino(struct page *page)
{
struct mem_cgroup *memcg;
unsigned long ino = 0;
rcu_read_lock();
/* page_folio() is racy here, but the entire function is racy anyway */
memcg = folio_memcg_check(page_folio(page));
while (memcg && !(memcg->css.flags & CSS_ONLINE))
memcg = parent_mem_cgroup(memcg);
if (memcg)
ino = cgroup_ino(memcg->css.cgroup);
rcu_read_unlock();
return ino;
}
static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_node *mz,
struct mem_cgroup_tree_per_node *mctz,
unsigned long new_usage_in_excess)
{
struct rb_node **p = &mctz->rb_root.rb_node;
struct rb_node *parent = NULL;
struct mem_cgroup_per_node *mz_node;
bool rightmost = true;
if (mz->on_tree)
return;
mz->usage_in_excess = new_usage_in_excess;
if (!mz->usage_in_excess)
return;
while (*p) {
parent = *p;
mz_node = rb_entry(parent, struct mem_cgroup_per_node,
tree_node);
if (mz->usage_in_excess < mz_node->usage_in_excess) {
p = &(*p)->rb_left;
rightmost = false;
} else {
p = &(*p)->rb_right;
}
}
if (rightmost)
mctz->rb_rightmost = &mz->tree_node;
rb_link_node(&mz->tree_node, parent, p);
rb_insert_color(&mz->tree_node, &mctz->rb_root);
mz->on_tree = true;
}
static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_node *mz,
struct mem_cgroup_tree_per_node *mctz)
{
if (!mz->on_tree)
return;
if (&mz->tree_node == mctz->rb_rightmost)
mctz->rb_rightmost = rb_prev(&mz->tree_node);
rb_erase(&mz->tree_node, &mctz->rb_root);
mz->on_tree = false;
}
static void mem_cgroup_remove_exceeded(struct mem_cgroup_per_node *mz,
struct mem_cgroup_tree_per_node *mctz)
{
unsigned long flags;
spin_lock_irqsave(&mctz->lock, flags);
__mem_cgroup_remove_exceeded(mz, mctz);
spin_unlock_irqrestore(&mctz->lock, flags);
}
static unsigned long soft_limit_excess(struct mem_cgroup *memcg)
{
unsigned long nr_pages = page_counter_read(&memcg->memory);
unsigned long soft_limit = READ_ONCE(memcg->soft_limit);
unsigned long excess = 0;
if (nr_pages > soft_limit)
excess = nr_pages - soft_limit;
return excess;
}
static void mem_cgroup_update_tree(struct mem_cgroup *memcg, int nid)
{
unsigned long excess;
struct mem_cgroup_per_node *mz;
struct mem_cgroup_tree_per_node *mctz;
if (lru_gen_enabled()) {
if (soft_limit_excess(memcg))
lru_gen_soft_reclaim(memcg, nid);
return;
}
mctz = soft_limit_tree.rb_tree_per_node[nid];
if (!mctz)
return;
/*
* Necessary to update all ancestors when hierarchy is used.
* because their event counter is not touched.
*/
for (; memcg; memcg = parent_mem_cgroup(memcg)) {
mz = memcg->nodeinfo[nid];
excess = soft_limit_excess(memcg);
/*
* We have to update the tree if mz is on RB-tree or
* mem is over its softlimit.
*/
if (excess || mz->on_tree) {
unsigned long flags;
spin_lock_irqsave(&mctz->lock, flags);
/* if on-tree, remove it */
if (mz->on_tree)
__mem_cgroup_remove_exceeded(mz, mctz);
/*
* Insert again. mz->usage_in_excess will be updated.
* If excess is 0, no tree ops.
*/
__mem_cgroup_insert_exceeded(mz, mctz, excess);
spin_unlock_irqrestore(&mctz->lock, flags);
}
}
}
static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg)
{
struct mem_cgroup_tree_per_node *mctz;
struct mem_cgroup_per_node *mz;
int nid;
for_each_node(nid) {
mz = memcg->nodeinfo[nid];
mctz = soft_limit_tree.rb_tree_per_node[nid];
if (mctz)
mem_cgroup_remove_exceeded(mz, mctz);
}
}
static struct mem_cgroup_per_node *
__mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz)
{
struct mem_cgroup_per_node *mz;
retry:
mz = NULL;
if (!mctz->rb_rightmost)
goto done; /* Nothing to reclaim from */
mz = rb_entry(mctz->rb_rightmost,
struct mem_cgroup_per_node, tree_node);
/*
* Remove the node now but someone else can add it back,
* we will to add it back at the end of reclaim to its correct
* position in the tree.
*/
__mem_cgroup_remove_exceeded(mz, mctz);
if (!soft_limit_excess(mz->memcg) ||
!css_tryget(&mz->memcg->css))
goto retry;
done:
return mz;
}
static struct mem_cgroup_per_node *
mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz)
{
struct mem_cgroup_per_node *mz;
spin_lock_irq(&mctz->lock);
mz = __mem_cgroup_largest_soft_limit_node(mctz);
spin_unlock_irq(&mctz->lock);
return mz;
}
/*
* memcg and lruvec stats flushing
*
* Many codepaths leading to stats update or read are performance sensitive and
* adding stats flushing in such codepaths is not desirable. So, to optimize the
* flushing the kernel does:
*
* 1) Periodically and asynchronously flush the stats every 2 seconds to not let
* rstat update tree grow unbounded.
*
* 2) Flush the stats synchronously on reader side only when there are more than
* (MEMCG_CHARGE_BATCH * nr_cpus) update events. Though this optimization
* will let stats be out of sync by atmost (MEMCG_CHARGE_BATCH * nr_cpus) but
* only for 2 seconds due to (1).
*/
static void flush_memcg_stats_dwork(struct work_struct *w);
static DECLARE_DEFERRABLE_WORK(stats_flush_dwork, flush_memcg_stats_dwork);
static DEFINE_PER_CPU(unsigned int, stats_updates);
static atomic_t stats_flush_ongoing = ATOMIC_INIT(0);
static atomic_t stats_flush_threshold = ATOMIC_INIT(0);
static u64 flush_next_time;
#define FLUSH_TIME (2UL*HZ)
/*
* Accessors to ensure that preemption is disabled on PREEMPT_RT because it can
* not rely on this as part of an acquired spinlock_t lock. These functions are
* never used in hardirq context on PREEMPT_RT and therefore disabling preemtion
* is sufficient.
*/
static void memcg_stats_lock(void)
{
preempt_disable_nested();
VM_WARN_ON_IRQS_ENABLED();
}
static void __memcg_stats_lock(void)
{
preempt_disable_nested();
}
static void memcg_stats_unlock(void)
{
preempt_enable_nested();
}
static inline void memcg_rstat_updated(struct mem_cgroup *memcg, int val)
{
unsigned int x;
if (!val)
return;
cgroup_rstat_updated(memcg->css.cgroup, smp_processor_id());
x = __this_cpu_add_return(stats_updates, abs(val));
if (x > MEMCG_CHARGE_BATCH) {
/*
* If stats_flush_threshold exceeds the threshold
* (>num_online_cpus()), cgroup stats update will be triggered
* in __mem_cgroup_flush_stats(). Increasing this var further
* is redundant and simply adds overhead in atomic update.
*/
if (atomic_read(&stats_flush_threshold) <= num_online_cpus())
atomic_add(x / MEMCG_CHARGE_BATCH, &stats_flush_threshold);
__this_cpu_write(stats_updates, 0);
}
}
static void do_flush_stats(void)
{
/*
* We always flush the entire tree, so concurrent flushers can just
* skip. This avoids a thundering herd problem on the rstat global lock
* from memcg flushers (e.g. reclaim, refault, etc).
*/
if (atomic_read(&stats_flush_ongoing) ||
atomic_xchg(&stats_flush_ongoing, 1))
return;
WRITE_ONCE(flush_next_time, jiffies_64 + 2*FLUSH_TIME);
cgroup_rstat_flush(root_mem_cgroup->css.cgroup);
atomic_set(&stats_flush_threshold, 0);
atomic_set(&stats_flush_ongoing, 0);
}
void mem_cgroup_flush_stats(void)
{
if (atomic_read(&stats_flush_threshold) > num_online_cpus())
do_flush_stats();
}
void mem_cgroup_flush_stats_ratelimited(void)
{
if (time_after64(jiffies_64, READ_ONCE(flush_next_time)))
mem_cgroup_flush_stats();
}
static void flush_memcg_stats_dwork(struct work_struct *w)
{
/*
* Always flush here so that flushing in latency-sensitive paths is
* as cheap as possible.
*/
do_flush_stats();
queue_delayed_work(system_unbound_wq, &stats_flush_dwork, FLUSH_TIME);
}
/* Subset of vm_event_item to report for memcg event stats */
static const unsigned int memcg_vm_event_stat[] = {
PGPGIN,
PGPGOUT,
PGSCAN_KSWAPD,
PGSCAN_DIRECT,
PGSCAN_KHUGEPAGED,
PGSTEAL_KSWAPD,
PGSTEAL_DIRECT,
PGSTEAL_KHUGEPAGED,
PGFAULT,
PGMAJFAULT,
PGREFILL,
PGACTIVATE,
PGDEACTIVATE,
PGLAZYFREE,
PGLAZYFREED,
#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP)
ZSWPIN,
ZSWPOUT,
#endif
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
THP_FAULT_ALLOC,
THP_COLLAPSE_ALLOC,
#endif
};
#define NR_MEMCG_EVENTS ARRAY_SIZE(memcg_vm_event_stat)
static int mem_cgroup_events_index[NR_VM_EVENT_ITEMS] __read_mostly;
static void init_memcg_events(void)
{
int i;
for (i = 0; i < NR_MEMCG_EVENTS; ++i)
mem_cgroup_events_index[memcg_vm_event_stat[i]] = i + 1;
}
static inline int memcg_events_index(enum vm_event_item idx)
{
return mem_cgroup_events_index[idx] - 1;
}
struct memcg_vmstats_percpu {
/* Local (CPU and cgroup) page state & events */
long state[MEMCG_NR_STAT];
unsigned long events[NR_MEMCG_EVENTS];
/* Delta calculation for lockless upward propagation */
long state_prev[MEMCG_NR_STAT];
unsigned long events_prev[NR_MEMCG_EVENTS];
/* Cgroup1: threshold notifications & softlimit tree updates */
unsigned long nr_page_events;
unsigned long targets[MEM_CGROUP_NTARGETS];
};
struct memcg_vmstats {
/* Aggregated (CPU and subtree) page state & events */
long state[MEMCG_NR_STAT];
unsigned long events[NR_MEMCG_EVENTS];
/* Non-hierarchical (CPU aggregated) page state & events */
long state_local[MEMCG_NR_STAT];
unsigned long events_local[NR_MEMCG_EVENTS];
/* Pending child counts during tree propagation */
long state_pending[MEMCG_NR_STAT];
unsigned long events_pending[NR_MEMCG_EVENTS];
};
unsigned long memcg_page_state(struct mem_cgroup *memcg, int idx)
{
long x = READ_ONCE(memcg->vmstats->state[idx]);
#ifdef CONFIG_SMP
if (x < 0)
x = 0;
#endif
return x;
}
/**
* __mod_memcg_state - update cgroup memory statistics
* @memcg: the memory cgroup
* @idx: the stat item - can be enum memcg_stat_item or enum node_stat_item
* @val: delta to add to the counter, can be negative
*/
void __mod_memcg_state(struct mem_cgroup *memcg, int idx, int val)
{
if (mem_cgroup_disabled())
return;
__this_cpu_add(memcg->vmstats_percpu->state[idx], val);
memcg_rstat_updated(memcg, val);
}
/* idx can be of type enum memcg_stat_item or node_stat_item. */
static unsigned long memcg_page_state_local(struct mem_cgroup *memcg, int idx)
{
long x = READ_ONCE(memcg->vmstats->state_local[idx]);
#ifdef CONFIG_SMP
if (x < 0)
x = 0;
#endif
return x;
}
void __mod_memcg_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
int val)
{
struct mem_cgroup_per_node *pn;
struct mem_cgroup *memcg;
pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
memcg = pn->memcg;
/*
* The caller from rmap relay on disabled preemption becase they never
* update their counter from in-interrupt context. For these two
* counters we check that the update is never performed from an
* interrupt context while other caller need to have disabled interrupt.
*/
__memcg_stats_lock();
if (IS_ENABLED(CONFIG_DEBUG_VM)) {
switch (idx) {
case NR_ANON_MAPPED:
case NR_FILE_MAPPED:
case NR_ANON_THPS:
case NR_SHMEM_PMDMAPPED:
case NR_FILE_PMDMAPPED:
WARN_ON_ONCE(!in_task());
break;
default:
VM_WARN_ON_IRQS_ENABLED();
}
}
/* Update memcg */
__this_cpu_add(memcg->vmstats_percpu->state[idx], val);
/* Update lruvec */
__this_cpu_add(pn->lruvec_stats_percpu->state[idx], val);
memcg_rstat_updated(memcg, val);
memcg_stats_unlock();
}
/**
* __mod_lruvec_state - update lruvec memory statistics
* @lruvec: the lruvec
* @idx: the stat item
* @val: delta to add to the counter, can be negative
*
* The lruvec is the intersection of the NUMA node and a cgroup. This
* function updates the all three counters that are affected by a
* change of state at this level: per-node, per-cgroup, per-lruvec.
*/
void __mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
int val)
{
/* Update node */
__mod_node_page_state(lruvec_pgdat(lruvec), idx, val);
/* Update memcg and lruvec */
if (!mem_cgroup_disabled())
__mod_memcg_lruvec_state(lruvec, idx, val);
}
void __mod_lruvec_page_state(struct page *page, enum node_stat_item idx,
int val)
{
struct page *head = compound_head(page); /* rmap on tail pages */
struct mem_cgroup *memcg;
pg_data_t *pgdat = page_pgdat(page);
struct lruvec *lruvec;
rcu_read_lock();
memcg = page_memcg(head);
/* Untracked pages have no memcg, no lruvec. Update only the node */
if (!memcg) {
rcu_read_unlock();
__mod_node_page_state(pgdat, idx, val);
return;
}
lruvec = mem_cgroup_lruvec(memcg, pgdat);
__mod_lruvec_state(lruvec, idx, val);
rcu_read_unlock();
}
EXPORT_SYMBOL(__mod_lruvec_page_state);
void __mod_lruvec_kmem_state(void *p, enum node_stat_item idx, int val)
{
pg_data_t *pgdat = page_pgdat(virt_to_page(p));
struct mem_cgroup *memcg;
struct lruvec *lruvec;
rcu_read_lock();
memcg = mem_cgroup_from_slab_obj(p);
/*
* Untracked pages have no memcg, no lruvec. Update only the
* node. If we reparent the slab objects to the root memcg,
* when we free the slab object, we need to update the per-memcg
* vmstats to keep it correct for the root memcg.
*/
if (!memcg) {
__mod_node_page_state(pgdat, idx, val);
} else {
lruvec = mem_cgroup_lruvec(memcg, pgdat);
__mod_lruvec_state(lruvec, idx, val);
}
rcu_read_unlock();
}
/**
* __count_memcg_events - account VM events in a cgroup
* @memcg: the memory cgroup
* @idx: the event item
* @count: the number of events that occurred
*/
void __count_memcg_events(struct mem_cgroup *memcg, enum vm_event_item idx,
unsigned long count)
{
int index = memcg_events_index(idx);
if (mem_cgroup_disabled() || index < 0)
return;
memcg_stats_lock();
__this_cpu_add(memcg->vmstats_percpu->events[index], count);
memcg_rstat_updated(memcg, count);
memcg_stats_unlock();
}
static unsigned long memcg_events(struct mem_cgroup *memcg, int event)
{
int index = memcg_events_index(event);
if (index < 0)
return 0;
return READ_ONCE(memcg->vmstats->events[index]);
}
static unsigned long memcg_events_local(struct mem_cgroup *memcg, int event)
{
int index = memcg_events_index(event);
if (index < 0)
return 0;
return READ_ONCE(memcg->vmstats->events_local[index]);
}
static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
int nr_pages)
{
/* pagein of a big page is an event. So, ignore page size */
if (nr_pages > 0)
__count_memcg_events(memcg, PGPGIN, 1);
else {
__count_memcg_events(memcg, PGPGOUT, 1);
nr_pages = -nr_pages; /* for event */
}
__this_cpu_add(memcg->vmstats_percpu->nr_page_events, nr_pages);
}
static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
enum mem_cgroup_events_target target)
{
unsigned long val, next;
val = __this_cpu_read(memcg->vmstats_percpu->nr_page_events);
next = __this_cpu_read(memcg->vmstats_percpu->targets[target]);
/* from time_after() in jiffies.h */
if ((long)(next - val) < 0) {
switch (target) {
case MEM_CGROUP_TARGET_THRESH:
next = val + THRESHOLDS_EVENTS_TARGET;
break;
case MEM_CGROUP_TARGET_SOFTLIMIT:
next = val + SOFTLIMIT_EVENTS_TARGET;
break;
default:
break;
}
__this_cpu_write(memcg->vmstats_percpu->targets[target], next);
return true;
}
return false;
}
/*
* Check events in order.
*
*/
static void memcg_check_events(struct mem_cgroup *memcg, int nid)
{
if (IS_ENABLED(CONFIG_PREEMPT_RT))
return;
/* threshold event is triggered in finer grain than soft limit */
if (unlikely(mem_cgroup_event_ratelimit(memcg,
MEM_CGROUP_TARGET_THRESH))) {
bool do_softlimit;
do_softlimit = mem_cgroup_event_ratelimit(memcg,
MEM_CGROUP_TARGET_SOFTLIMIT);
mem_cgroup_threshold(memcg);
if (unlikely(do_softlimit))
mem_cgroup_update_tree(memcg, nid);
}
}
struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
{
/*
* mm_update_next_owner() may clear mm->owner to NULL
* if it races with swapoff, page migration, etc.
* So this can be called with p == NULL.
*/
if (unlikely(!p))
return NULL;
return mem_cgroup_from_css(task_css(p, memory_cgrp_id));
}
EXPORT_SYMBOL(mem_cgroup_from_task);
static __always_inline struct mem_cgroup *active_memcg(void)
{
if (!in_task())
return this_cpu_read(int_active_memcg);
else
return current->active_memcg;
}
/**
* get_mem_cgroup_from_mm: Obtain a reference on given mm_struct's memcg.
* @mm: mm from which memcg should be extracted. It can be NULL.
*
* Obtain a reference on mm->memcg and returns it if successful. If mm
* is NULL, then the memcg is chosen as follows:
* 1) The active memcg, if set.
* 2) current->mm->memcg, if available
* 3) root memcg
* If mem_cgroup is disabled, NULL is returned.
*/
struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm)
{
struct mem_cgroup *memcg;
if (mem_cgroup_disabled())
return NULL;
/*
* Page cache insertions can happen without an
* actual mm context, e.g. during disk probing
* on boot, loopback IO, acct() writes etc.
*
* No need to css_get on root memcg as the reference
* counting is disabled on the root level in the
* cgroup core. See CSS_NO_REF.
*/
if (unlikely(!mm)) {
memcg = active_memcg();
if (unlikely(memcg)) {
/* remote memcg must hold a ref */
css_get(&memcg->css);
return memcg;
}
mm = current->mm;
if (unlikely(!mm))
return root_mem_cgroup;
}
rcu_read_lock();
do {
memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
if (unlikely(!memcg))
memcg = root_mem_cgroup;
} while (!css_tryget(&memcg->css));
rcu_read_unlock();
return memcg;
}
EXPORT_SYMBOL(get_mem_cgroup_from_mm);
static __always_inline bool memcg_kmem_bypass(void)
{
/* Allow remote memcg charging from any context. */
if (unlikely(active_memcg()))
return false;
/* Memcg to charge can't be determined. */
if (!in_task() || !current->mm || (current->flags & PF_KTHREAD))
return true;
return false;
}
/**
* mem_cgroup_iter - iterate over memory cgroup hierarchy
* @root: hierarchy root
* @prev: previously returned memcg, NULL on first invocation
* @reclaim: cookie for shared reclaim walks, NULL for full walks
*
* Returns references to children of the hierarchy below @root, or
* @root itself, or %NULL after a full round-trip.
*
* Caller must pass the return value in @prev on subsequent
* invocations for reference counting, or use mem_cgroup_iter_break()
* to cancel a hierarchy walk before the round-trip is complete.
*
* Reclaimers can specify a node in @reclaim to divide up the memcgs
* in the hierarchy among all concurrent reclaimers operating on the
* same node.
*/
struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
struct mem_cgroup *prev,
struct mem_cgroup_reclaim_cookie *reclaim)
{
struct mem_cgroup_reclaim_iter *iter;
struct cgroup_subsys_state *css = NULL;
struct mem_cgroup *memcg = NULL;
struct mem_cgroup *pos = NULL;
if (mem_cgroup_disabled())
return NULL;
if (!root)
root = root_mem_cgroup;
rcu_read_lock();
if (reclaim) {
struct mem_cgroup_per_node *mz;
mz = root->nodeinfo[reclaim->pgdat->node_id];
iter = &mz->iter;
/*
* On start, join the current reclaim iteration cycle.
* Exit when a concurrent walker completes it.
*/
if (!prev)
reclaim->generation = iter->generation;
else if (reclaim->generation != iter->generation)
goto out_unlock;
while (1) {
pos = READ_ONCE(iter->position);
if (!pos || css_tryget(&pos->css))
break;
/*
* css reference reached zero, so iter->position will
* be cleared by ->css_released. However, we should not
* rely on this happening soon, because ->css_released
* is called from a work queue, and by busy-waiting we
* might block it. So we clear iter->position right
* away.
*/
(void)cmpxchg(&iter->position, pos, NULL);
}
} else if (prev) {
pos = prev;
}
if (pos)
css = &pos->css;
for (;;) {
css = css_next_descendant_pre(css, &root->css);
if (!css) {
/*
* Reclaimers share the hierarchy walk, and a
* new one might jump in right at the end of
* the hierarchy - make sure they see at least
* one group and restart from the beginning.
*/
if (!prev)
continue;
break;
}
/*
* Verify the css and acquire a reference. The root
* is provided by the caller, so we know it's alive
* and kicking, and don't take an extra reference.
*/
if (css == &root->css || css_tryget(css)) {
memcg = mem_cgroup_from_css(css);
break;
}
}
if (reclaim) {
/*
* The position could have already been updated by a competing
* thread, so check that the value hasn't changed since we read
* it to avoid reclaiming from the same cgroup twice.
*/
(void)cmpxchg(&iter->position, pos, memcg);
if (pos)
css_put(&pos->css);
if (!memcg)
iter->generation++;
}
out_unlock:
rcu_read_unlock();
if (prev && prev != root)
css_put(&prev->css);
return memcg;
}
/**
* mem_cgroup_iter_break - abort a hierarchy walk prematurely
* @root: hierarchy root
* @prev: last visited hierarchy member as returned by mem_cgroup_iter()
*/
void mem_cgroup_iter_break(struct mem_cgroup *root,
struct mem_cgroup *prev)
{
if (!root)
root = root_mem_cgroup;
if (prev && prev != root)
css_put(&prev->css);
}
static void __invalidate_reclaim_iterators(struct mem_cgroup *from,
struct mem_cgroup *dead_memcg)
{
struct mem_cgroup_reclaim_iter *iter;
struct mem_cgroup_per_node *mz;
int nid;
for_each_node(nid) {
mz = from->nodeinfo[nid];
iter = &mz->iter;
cmpxchg(&iter->position, dead_memcg, NULL);
}
}
static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg)
{
struct mem_cgroup *memcg = dead_memcg;
struct mem_cgroup *last;
do {
__invalidate_reclaim_iterators(memcg, dead_memcg);
last = memcg;
} while ((memcg = parent_mem_cgroup(memcg)));
/*
* When cgroup1 non-hierarchy mode is used,
* parent_mem_cgroup() does not walk all the way up to the
* cgroup root (root_mem_cgroup). So we have to handle
* dead_memcg from cgroup root separately.
*/
if (!mem_cgroup_is_root(last))
__invalidate_reclaim_iterators(root_mem_cgroup,
dead_memcg);
}
/**
* mem_cgroup_scan_tasks - iterate over tasks of a memory cgroup hierarchy
* @memcg: hierarchy root
* @fn: function to call for each task
* @arg: argument passed to @fn
*
* This function iterates over tasks attached to @memcg or to any of its
* descendants and calls @fn for each task. If @fn returns a non-zero
* value, the function breaks the iteration loop. Otherwise, it will iterate
* over all tasks and return 0.
*
* This function must not be called for the root memory cgroup.
*/
void mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
int (*fn)(struct task_struct *, void *), void *arg)
{
struct mem_cgroup *iter;
int ret = 0;
BUG_ON(mem_cgroup_is_root(memcg));
for_each_mem_cgroup_tree(iter, memcg) {
struct css_task_iter it;
struct task_struct *task;
css_task_iter_start(&iter->css, CSS_TASK_ITER_PROCS, &it);
while (!ret && (task = css_task_iter_next(&it)))
ret = fn(task, arg);
css_task_iter_end(&it);
if (ret) {
mem_cgroup_iter_break(memcg, iter);
break;
}
}
}
#ifdef CONFIG_DEBUG_VM
void lruvec_memcg_debug(struct lruvec *lruvec, struct folio *folio)
{
struct mem_cgroup *memcg;
if (mem_cgroup_disabled())
return;
memcg = folio_memcg(folio);
if (!memcg)
VM_BUG_ON_FOLIO(!mem_cgroup_is_root(lruvec_memcg(lruvec)), folio);
else
VM_BUG_ON_FOLIO(lruvec_memcg(lruvec) != memcg, folio);
}
#endif
/**
* folio_lruvec_lock - Lock the lruvec for a folio.
* @folio: Pointer to the folio.
*
* These functions are safe to use under any of the following conditions:
* - folio locked
* - folio_test_lru false
* - folio_memcg_lock()
* - folio frozen (refcount of 0)
*
* Return: The lruvec this folio is on with its lock held.
*/
struct lruvec *folio_lruvec_lock(struct folio *folio)
{
struct lruvec *lruvec = folio_lruvec(folio);
spin_lock(&lruvec->lru_lock);
lruvec_memcg_debug(lruvec, folio);
return lruvec;
}
/**
* folio_lruvec_lock_irq - Lock the lruvec for a folio.
* @folio: Pointer to the folio.
*
* These functions are safe to use under any of the following conditions:
* - folio locked
* - folio_test_lru false
* - folio_memcg_lock()
* - folio frozen (refcount of 0)
*
* Return: The lruvec this folio is on with its lock held and interrupts
* disabled.
*/
struct lruvec *folio_lruvec_lock_irq(struct folio *folio)
{
struct lruvec *lruvec = folio_lruvec(folio);
spin_lock_irq(&lruvec->lru_lock);
lruvec_memcg_debug(lruvec, folio);
return lruvec;
}
/**
* folio_lruvec_lock_irqsave - Lock the lruvec for a folio.
* @folio: Pointer to the folio.
* @flags: Pointer to irqsave flags.
*
* These functions are safe to use under any of the following conditions:
* - folio locked
* - folio_test_lru false
* - folio_memcg_lock()
* - folio frozen (refcount of 0)
*
* Return: The lruvec this folio is on with its lock held and interrupts
* disabled.
*/
struct lruvec *folio_lruvec_lock_irqsave(struct folio *folio,
unsigned long *flags)
{
struct lruvec *lruvec = folio_lruvec(folio);
spin_lock_irqsave(&lruvec->lru_lock, *flags);
lruvec_memcg_debug(lruvec, folio);
return lruvec;
}
/**
* mem_cgroup_update_lru_size - account for adding or removing an lru page
* @lruvec: mem_cgroup per zone lru vector
* @lru: index of lru list the page is sitting on
* @zid: zone id of the accounted pages
* @nr_pages: positive when adding or negative when removing
*
* This function must be called under lru_lock, just before a page is added
* to or just after a page is removed from an lru list.
*/
void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
int zid, int nr_pages)
{
struct mem_cgroup_per_node *mz;
unsigned long *lru_size;
long size;
if (mem_cgroup_disabled())
return;
mz = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
lru_size = &mz->lru_zone_size[zid][lru];
if (nr_pages < 0)
*lru_size += nr_pages;
size = *lru_size;
if (WARN_ONCE(size < 0,
"%s(%p, %d, %d): lru_size %ld\n",
__func__, lruvec, lru, nr_pages, size)) {
VM_BUG_ON(1);
*lru_size = 0;
}
if (nr_pages > 0)
*lru_size += nr_pages;
}
/**
* mem_cgroup_margin - calculate chargeable space of a memory cgroup
* @memcg: the memory cgroup
*
* Returns the maximum amount of memory @mem can be charged with, in
* pages.
*/
static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg)
{
unsigned long margin = 0;
unsigned long count;
unsigned long limit;
count = page_counter_read(&memcg->memory);
limit = READ_ONCE(memcg->memory.max);
if (count < limit)
margin = limit - count;
if (do_memsw_account()) {
count = page_counter_read(&memcg->memsw);
limit = READ_ONCE(memcg->memsw.max);
if (count < limit)
margin = min(margin, limit - count);
else
margin = 0;
}
return margin;
}
/*
* A routine for checking "mem" is under move_account() or not.
*
* Checking a cgroup is mc.from or mc.to or under hierarchy of
* moving cgroups. This is for waiting at high-memory pressure
* caused by "move".
*/
static bool mem_cgroup_under_move(struct mem_cgroup *memcg)
{
struct mem_cgroup *from;
struct mem_cgroup *to;
bool ret = false;
/*
* Unlike task_move routines, we access mc.to, mc.from not under
* mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
*/
spin_lock(&mc.lock);
from = mc.from;
to = mc.to;
if (!from)
goto unlock;
ret = mem_cgroup_is_descendant(from, memcg) ||
mem_cgroup_is_descendant(to, memcg);
unlock:
spin_unlock(&mc.lock);
return ret;
}
static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg)
{
if (mc.moving_task && current != mc.moving_task) {
if (mem_cgroup_under_move(memcg)) {
DEFINE_WAIT(wait);
prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE);
/* moving charge context might have finished. */
if (mc.moving_task)
schedule();
finish_wait(&mc.waitq, &wait);
return true;
}
}
return false;
}
struct memory_stat {
const char *name;
unsigned int idx;
};
static const struct memory_stat memory_stats[] = {
{ "anon", NR_ANON_MAPPED },
{ "file", NR_FILE_PAGES },
{ "kernel", MEMCG_KMEM },
{ "kernel_stack", NR_KERNEL_STACK_KB },
{ "pagetables", NR_PAGETABLE },
{ "sec_pagetables", NR_SECONDARY_PAGETABLE },
{ "percpu", MEMCG_PERCPU_B },
{ "sock", MEMCG_SOCK },
{ "vmalloc", MEMCG_VMALLOC },
{ "shmem", NR_SHMEM },
#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP)
{ "zswap", MEMCG_ZSWAP_B },
{ "zswapped", MEMCG_ZSWAPPED },
#endif
{ "file_mapped", NR_FILE_MAPPED },
{ "file_dirty", NR_FILE_DIRTY },
{ "file_writeback", NR_WRITEBACK },
#ifdef CONFIG_SWAP
{ "swapcached", NR_SWAPCACHE },
#endif
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
{ "anon_thp", NR_ANON_THPS },
{ "file_thp", NR_FILE_THPS },
{ "shmem_thp", NR_SHMEM_THPS },
#endif
{ "inactive_anon", NR_INACTIVE_ANON },
{ "active_anon", NR_ACTIVE_ANON },
{ "inactive_file", NR_INACTIVE_FILE },
{ "active_file", NR_ACTIVE_FILE },
{ "unevictable", NR_UNEVICTABLE },
{ "slab_reclaimable", NR_SLAB_RECLAIMABLE_B },
{ "slab_unreclaimable", NR_SLAB_UNRECLAIMABLE_B },
/* The memory events */
{ "workingset_refault_anon", WORKINGSET_REFAULT_ANON },
{ "workingset_refault_file", WORKINGSET_REFAULT_FILE },
{ "workingset_activate_anon", WORKINGSET_ACTIVATE_ANON },
{ "workingset_activate_file", WORKINGSET_ACTIVATE_FILE },
{ "workingset_restore_anon", WORKINGSET_RESTORE_ANON },
{ "workingset_restore_file", WORKINGSET_RESTORE_FILE },
{ "workingset_nodereclaim", WORKINGSET_NODERECLAIM },
};
/* Translate stat items to the correct unit for memory.stat output */
static int memcg_page_state_unit(int item)
{
switch (item) {
case MEMCG_PERCPU_B:
case MEMCG_ZSWAP_B:
case NR_SLAB_RECLAIMABLE_B:
case NR_SLAB_UNRECLAIMABLE_B:
case WORKINGSET_REFAULT_ANON:
case WORKINGSET_REFAULT_FILE:
case WORKINGSET_ACTIVATE_ANON:
case WORKINGSET_ACTIVATE_FILE:
case WORKINGSET_RESTORE_ANON:
case WORKINGSET_RESTORE_FILE:
case WORKINGSET_NODERECLAIM:
return 1;
case NR_KERNEL_STACK_KB:
return SZ_1K;
default:
return PAGE_SIZE;
}
}
static inline unsigned long memcg_page_state_output(struct mem_cgroup *memcg,
int item)
{
return memcg_page_state(memcg, item) * memcg_page_state_unit(item);
}
static void memcg_stat_format(struct mem_cgroup *memcg, struct seq_buf *s)
{
int i;
/*
* Provide statistics on the state of the memory subsystem as
* well as cumulative event counters that show past behavior.
*
* This list is ordered following a combination of these gradients:
* 1) generic big picture -> specifics and details
* 2) reflecting userspace activity -> reflecting kernel heuristics
*
* Current memory state:
*/
mem_cgroup_flush_stats();
for (i = 0; i < ARRAY_SIZE(memory_stats); i++) {
u64 size;
size = memcg_page_state_output(memcg, memory_stats[i].idx);
seq_buf_printf(s, "%s %llu\n", memory_stats[i].name, size);
if (unlikely(memory_stats[i].idx == NR_SLAB_UNRECLAIMABLE_B)) {
size += memcg_page_state_output(memcg,
NR_SLAB_RECLAIMABLE_B);
seq_buf_printf(s, "slab %llu\n", size);
}
}
/* Accumulated memory events */
seq_buf_printf(s, "pgscan %lu\n",
memcg_events(memcg, PGSCAN_KSWAPD) +
memcg_events(memcg, PGSCAN_DIRECT) +
memcg_events(memcg, PGSCAN_KHUGEPAGED));
seq_buf_printf(s, "pgsteal %lu\n",
memcg_events(memcg, PGSTEAL_KSWAPD) +
memcg_events(memcg, PGSTEAL_DIRECT) +
memcg_events(memcg, PGSTEAL_KHUGEPAGED));
for (i = 0; i < ARRAY_SIZE(memcg_vm_event_stat); i++) {
if (memcg_vm_event_stat[i] == PGPGIN ||
memcg_vm_event_stat[i] == PGPGOUT)
continue;
seq_buf_printf(s, "%s %lu\n",
vm_event_name(memcg_vm_event_stat[i]),
memcg_events(memcg, memcg_vm_event_stat[i]));
}
/* The above should easily fit into one page */
WARN_ON_ONCE(seq_buf_has_overflowed(s));
}
static void memcg1_stat_format(struct mem_cgroup *memcg, struct seq_buf *s);
static void memory_stat_format(struct mem_cgroup *memcg, struct seq_buf *s)
{
if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
memcg_stat_format(memcg, s);
else
memcg1_stat_format(memcg, s);
WARN_ON_ONCE(seq_buf_has_overflowed(s));
}
/**
* mem_cgroup_print_oom_context: Print OOM information relevant to
* memory controller.
* @memcg: The memory cgroup that went over limit
* @p: Task that is going to be killed
*
* NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
* enabled
*/
void mem_cgroup_print_oom_context(struct mem_cgroup *memcg, struct task_struct *p)
{
rcu_read_lock();
if (memcg) {
pr_cont(",oom_memcg=");
pr_cont_cgroup_path(memcg->css.cgroup);
} else
pr_cont(",global_oom");
if (p) {
pr_cont(",task_memcg=");
pr_cont_cgroup_path(task_cgroup(p, memory_cgrp_id));
}
rcu_read_unlock();
}
/**
* mem_cgroup_print_oom_meminfo: Print OOM memory information relevant to
* memory controller.
* @memcg: The memory cgroup that went over limit
*/
void mem_cgroup_print_oom_meminfo(struct mem_cgroup *memcg)
{
/* Use static buffer, for the caller is holding oom_lock. */
static char buf[PAGE_SIZE];
struct seq_buf s;
lockdep_assert_held(&oom_lock);
pr_info("memory: usage %llukB, limit %llukB, failcnt %lu\n",
K((u64)page_counter_read(&memcg->memory)),
K((u64)READ_ONCE(memcg->memory.max)), memcg->memory.failcnt);
if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
pr_info("swap: usage %llukB, limit %llukB, failcnt %lu\n",
K((u64)page_counter_read(&memcg->swap)),
K((u64)READ_ONCE(memcg->swap.max)), memcg->swap.failcnt);
else {
pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %lu\n",
K((u64)page_counter_read(&memcg->memsw)),
K((u64)memcg->memsw.max), memcg->memsw.failcnt);
pr_info("kmem: usage %llukB, limit %llukB, failcnt %lu\n",
K((u64)page_counter_read(&memcg->kmem)),
K((u64)memcg->kmem.max), memcg->kmem.failcnt);
}
pr_info("Memory cgroup stats for ");
pr_cont_cgroup_path(memcg->css.cgroup);
pr_cont(":");
seq_buf_init(&s, buf, sizeof(buf));
memory_stat_format(memcg, &s);
seq_buf_do_printk(&s, KERN_INFO);
}
/*
* Return the memory (and swap, if configured) limit for a memcg.
*/
unsigned long mem_cgroup_get_max(struct mem_cgroup *memcg)
{
unsigned long max = READ_ONCE(memcg->memory.max);
if (do_memsw_account()) {
if (mem_cgroup_swappiness(memcg)) {
/* Calculate swap excess capacity from memsw limit */
unsigned long swap = READ_ONCE(memcg->memsw.max) - max;
max += min(swap, (unsigned long)total_swap_pages);
}
} else {
if (mem_cgroup_swappiness(memcg))
max += min(READ_ONCE(memcg->swap.max),
(unsigned long)total_swap_pages);
}
return max;
}
unsigned long mem_cgroup_size(struct mem_cgroup *memcg)
{
return page_counter_read(&memcg->memory);
}
static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
int order)
{
struct oom_control oc = {
.zonelist = NULL,
.nodemask = NULL,
.memcg = memcg,
.gfp_mask = gfp_mask,
.order = order,
};
bool ret = true;
if (mutex_lock_killable(&oom_lock))
return true;
if (mem_cgroup_margin(memcg) >= (1 << order))
goto unlock;
/*
* A few threads which were not waiting at mutex_lock_killable() can
* fail to bail out. Therefore, check again after holding oom_lock.
*/
ret = task_is_dying() || out_of_memory(&oc);
unlock:
mutex_unlock(&oom_lock);
return ret;
}
static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg,
pg_data_t *pgdat,
gfp_t gfp_mask,
unsigned long *total_scanned)
{
struct mem_cgroup *victim = NULL;
int total = 0;
int loop = 0;
unsigned long excess;
unsigned long nr_scanned;
struct mem_cgroup_reclaim_cookie reclaim = {
.pgdat = pgdat,
};
excess = soft_limit_excess(root_memcg);
while (1) {
victim = mem_cgroup_iter(root_memcg, victim, &reclaim);
if (!victim) {
loop++;
if (loop >= 2) {
/*
* If we have not been able to reclaim
* anything, it might because there are
* no reclaimable pages under this hierarchy
*/
if (!total)
break;
/*
* We want to do more targeted reclaim.
* excess >> 2 is not to excessive so as to
* reclaim too much, nor too less that we keep
* coming back to reclaim from this cgroup
*/
if (total >= (excess >> 2) ||
(loop > MEM_CGROUP_MAX_RECLAIM_LOOPS))
break;
}
continue;
}
total += mem_cgroup_shrink_node(victim, gfp_mask, false,
pgdat, &nr_scanned);
*total_scanned += nr_scanned;
if (!soft_limit_excess(root_memcg))
break;
}
mem_cgroup_iter_break(root_memcg, victim);
return total;
}
#ifdef CONFIG_LOCKDEP
static struct lockdep_map memcg_oom_lock_dep_map = {
.name = "memcg_oom_lock",
};
#endif
static DEFINE_SPINLOCK(memcg_oom_lock);
/*
* Check OOM-Killer is already running under our hierarchy.
* If someone is running, return false.
*/
static bool mem_cgroup_oom_trylock(struct mem_cgroup *memcg)
{
struct mem_cgroup *iter, *failed = NULL;
spin_lock(&memcg_oom_lock);
for_each_mem_cgroup_tree(iter, memcg) {
if (iter->oom_lock) {
/*
* this subtree of our hierarchy is already locked
* so we cannot give a lock.
*/
failed = iter;
mem_cgroup_iter_break(memcg, iter);
break;
} else
iter->oom_lock = true;
}
if (failed) {
/*
* OK, we failed to lock the whole subtree so we have
* to clean up what we set up to the failing subtree
*/
for_each_mem_cgroup_tree(iter, memcg) {
if (iter == failed) {
mem_cgroup_iter_break(memcg, iter);
break;
}
iter->oom_lock = false;
}
} else
mutex_acquire(&memcg_oom_lock_dep_map, 0, 1, _RET_IP_);
spin_unlock(&memcg_oom_lock);
return !failed;
}
static void mem_cgroup_oom_unlock(struct mem_cgroup *memcg)
{
struct mem_cgroup *iter;
spin_lock(&memcg_oom_lock);
mutex_release(&memcg_oom_lock_dep_map, _RET_IP_);
for_each_mem_cgroup_tree(iter, memcg)
iter->oom_lock = false;
spin_unlock(&memcg_oom_lock);
}
static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg)
{
struct mem_cgroup *iter;
spin_lock(&memcg_oom_lock);
for_each_mem_cgroup_tree(iter, memcg)
iter->under_oom++;
spin_unlock(&memcg_oom_lock);
}
static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg)
{
struct mem_cgroup *iter;
/*
* Be careful about under_oom underflows because a child memcg
* could have been added after mem_cgroup_mark_under_oom.
*/
spin_lock(&memcg_oom_lock);
for_each_mem_cgroup_tree(iter, memcg)
if (iter->under_oom > 0)
iter->under_oom--;
spin_unlock(&memcg_oom_lock);
}
static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);
struct oom_wait_info {
struct mem_cgroup *memcg;
wait_queue_entry_t wait;
};
static int memcg_oom_wake_function(wait_queue_entry_t *wait,
unsigned mode, int sync, void *arg)
{
struct mem_cgroup *wake_memcg = (struct mem_cgroup *)arg;
struct mem_cgroup *oom_wait_memcg;
struct oom_wait_info *oom_wait_info;
oom_wait_info = container_of(wait, struct oom_wait_info, wait);
oom_wait_memcg = oom_wait_info->memcg;
if (!mem_cgroup_is_descendant(wake_memcg, oom_wait_memcg) &&
!mem_cgroup_is_descendant(oom_wait_memcg, wake_memcg))
return 0;
return autoremove_wake_function(wait, mode, sync, arg);
}
static void memcg_oom_recover(struct mem_cgroup *memcg)
{
/*
* For the following lockless ->under_oom test, the only required
* guarantee is that it must see the state asserted by an OOM when
* this function is called as a result of userland actions
* triggered by the notification of the OOM. This is trivially
* achieved by invoking mem_cgroup_mark_under_oom() before
* triggering notification.
*/
if (memcg && memcg->under_oom)
__wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg);
}
/*
* Returns true if successfully killed one or more processes. Though in some
* corner cases it can return true even without killing any process.
*/
static bool mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order)
{
bool locked, ret;
if (order > PAGE_ALLOC_COSTLY_ORDER)
return false;
memcg_memory_event(memcg, MEMCG_OOM);
/*
* We are in the middle of the charge context here, so we
* don't want to block when potentially sitting on a callstack
* that holds all kinds of filesystem and mm locks.
*
* cgroup1 allows disabling the OOM killer and waiting for outside
* handling until the charge can succeed; remember the context and put
* the task to sleep at the end of the page fault when all locks are
* released.
*
* On the other hand, in-kernel OOM killer allows for an async victim
* memory reclaim (oom_reaper) and that means that we are not solely
* relying on the oom victim to make a forward progress and we can
* invoke the oom killer here.
*
* Please note that mem_cgroup_out_of_memory might fail to find a
* victim and then we have to bail out from the charge path.
*/
if (READ_ONCE(memcg->oom_kill_disable)) {
if (current->in_user_fault) {
css_get(&memcg->css);
current->memcg_in_oom = memcg;
current->memcg_oom_gfp_mask = mask;
current->memcg_oom_order = order;
}
return false;
}
mem_cgroup_mark_under_oom(memcg);
locked = mem_cgroup_oom_trylock(memcg);
if (locked)
mem_cgroup_oom_notify(memcg);
mem_cgroup_unmark_under_oom(memcg);
ret = mem_cgroup_out_of_memory(memcg, mask, order);
if (locked)
mem_cgroup_oom_unlock(memcg);
return ret;
}
/**
* mem_cgroup_oom_synchronize - complete memcg OOM handling
* @handle: actually kill/wait or just clean up the OOM state
*
* This has to be called at the end of a page fault if the memcg OOM
* handler was enabled.
*
* Memcg supports userspace OOM handling where failed allocations must
* sleep on a waitqueue until the userspace task resolves the
* situation. Sleeping directly in the charge context with all kinds
* of locks held is not a good idea, instead we remember an OOM state
* in the task and mem_cgroup_oom_synchronize() has to be called at
* the end of the page fault to complete the OOM handling.
*
* Returns %true if an ongoing memcg OOM situation was detected and
* completed, %false otherwise.
*/
bool mem_cgroup_oom_synchronize(bool handle)
{
struct mem_cgroup *memcg = current->memcg_in_oom;
struct oom_wait_info owait;
bool locked;
/* OOM is global, do not handle */
if (!memcg)
return false;
if (!handle)
goto cleanup;
owait.memcg = memcg;
owait.wait.flags = 0;
owait.wait.func = memcg_oom_wake_function;
owait.wait.private = current;
INIT_LIST_HEAD(&owait.wait.entry);
prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
mem_cgroup_mark_under_oom(memcg);
locked = mem_cgroup_oom_trylock(memcg);
if (locked)
mem_cgroup_oom_notify(memcg);
schedule();
mem_cgroup_unmark_under_oom(memcg);
finish_wait(&memcg_oom_waitq, &owait.wait);
if (locked)
mem_cgroup_oom_unlock(memcg);
cleanup:
current->memcg_in_oom = NULL;
css_put(&memcg->css);
return true;
}
/**
* mem_cgroup_get_oom_group - get a memory cgroup to clean up after OOM
* @victim: task to be killed by the OOM killer
* @oom_domain: memcg in case of memcg OOM, NULL in case of system-wide OOM
*
* Returns a pointer to a memory cgroup, which has to be cleaned up
* by killing all belonging OOM-killable tasks.
*
* Caller has to call mem_cgroup_put() on the returned non-NULL memcg.
*/
struct mem_cgroup *mem_cgroup_get_oom_group(struct task_struct *victim,
struct mem_cgroup *oom_domain)
{
struct mem_cgroup *oom_group = NULL;
struct mem_cgroup *memcg;
if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
return NULL;
if (!oom_domain)
oom_domain = root_mem_cgroup;
rcu_read_lock();
memcg = mem_cgroup_from_task(victim);
if (mem_cgroup_is_root(memcg))
goto out;
/*
* If the victim task has been asynchronously moved to a different
* memory cgroup, we might end up killing tasks outside oom_domain.
* In this case it's better to ignore memory.group.oom.
*/
if (unlikely(!mem_cgroup_is_descendant(memcg, oom_domain)))
goto out;
/*
* Traverse the memory cgroup hierarchy from the victim task's
* cgroup up to the OOMing cgroup (or root) to find the
* highest-level memory cgroup with oom.group set.
*/
for (; memcg; memcg = parent_mem_cgroup(memcg)) {
if (READ_ONCE(memcg->oom_group))
oom_group = memcg;
if (memcg == oom_domain)
break;
}
if (oom_group)
css_get(&oom_group->css);
out:
rcu_read_unlock();
return oom_group;
}
void mem_cgroup_print_oom_group(struct mem_cgroup *memcg)
{
pr_info("Tasks in ");
pr_cont_cgroup_path(memcg->css.cgroup);
pr_cont(" are going to be killed due to memory.oom.group set\n");
}
/**
* folio_memcg_lock - Bind a folio to its memcg.
* @folio: The folio.
*
* This function prevents unlocked LRU folios from being moved to
* another cgroup.
*
* It ensures lifetime of the bound memcg. The caller is responsible
* for the lifetime of the folio.
*/
void folio_memcg_lock(struct folio *folio)
{
struct mem_cgroup *memcg;
unsigned long flags;
/*
* The RCU lock is held throughout the transaction. The fast
* path can get away without acquiring the memcg->move_lock
* because page moving starts with an RCU grace period.
*/
rcu_read_lock();
if (mem_cgroup_disabled())
return;
again:
memcg = folio_memcg(folio);
if (unlikely(!memcg))
return;
#ifdef CONFIG_PROVE_LOCKING
local_irq_save(flags);
might_lock(&memcg->move_lock);
local_irq_restore(flags);
#endif
if (atomic_read(&memcg->moving_account) <= 0)
return;
spin_lock_irqsave(&memcg->move_lock, flags);
if (memcg != folio_memcg(folio)) {
spin_unlock_irqrestore(&memcg->move_lock, flags);
goto again;
}
/*
* When charge migration first begins, we can have multiple
* critical sections holding the fast-path RCU lock and one
* holding the slowpath move_lock. Track the task who has the
* move_lock for folio_memcg_unlock().
*/
memcg->move_lock_task = current;
memcg->move_lock_flags = flags;
}
static void __folio_memcg_unlock(struct mem_cgroup *memcg)
{
if (memcg && memcg->move_lock_task == current) {
unsigned long flags = memcg->move_lock_flags;
memcg->move_lock_task = NULL;
memcg->move_lock_flags = 0;
spin_unlock_irqrestore(&memcg->move_lock, flags);
}
rcu_read_unlock();
}
/**
* folio_memcg_unlock - Release the binding between a folio and its memcg.
* @folio: The folio.
*
* This releases the binding created by folio_memcg_lock(). This does
* not change the accounting of this folio to its memcg, but it does
* permit others to change it.
*/
void folio_memcg_unlock(struct folio *folio)
{
__folio_memcg_unlock(folio_memcg(folio));
}
struct memcg_stock_pcp {
local_lock_t stock_lock;
struct mem_cgroup *cached; /* this never be root cgroup */
unsigned int nr_pages;
#ifdef CONFIG_MEMCG_KMEM
struct obj_cgroup *cached_objcg;
struct pglist_data *cached_pgdat;
unsigned int nr_bytes;
int nr_slab_reclaimable_b;
int nr_slab_unreclaimable_b;
#endif
struct work_struct work;
unsigned long flags;
#define FLUSHING_CACHED_CHARGE 0
};
static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock) = {
.stock_lock = INIT_LOCAL_LOCK(stock_lock),
};
static DEFINE_MUTEX(percpu_charge_mutex);
#ifdef CONFIG_MEMCG_KMEM
static struct obj_cgroup *drain_obj_stock(struct memcg_stock_pcp *stock);
static bool obj_stock_flush_required(struct memcg_stock_pcp *stock,
struct mem_cgroup *root_memcg);
static void memcg_account_kmem(struct mem_cgroup *memcg, int nr_pages);
#else
static inline struct obj_cgroup *drain_obj_stock(struct memcg_stock_pcp *stock)
{
return NULL;
}
static bool obj_stock_flush_required(struct memcg_stock_pcp *stock,
struct mem_cgroup *root_memcg)
{
return false;
}
static void memcg_account_kmem(struct mem_cgroup *memcg, int nr_pages)
{
}
#endif
/**
* consume_stock: Try to consume stocked charge on this cpu.
* @memcg: memcg to consume from.
* @nr_pages: how many pages to charge.
*
* The charges will only happen if @memcg matches the current cpu's memcg
* stock, and at least @nr_pages are available in that stock. Failure to
* service an allocation will refill the stock.
*
* returns true if successful, false otherwise.
*/
static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
{
struct memcg_stock_pcp *stock;
unsigned long flags;
bool ret = false;
if (nr_pages > MEMCG_CHARGE_BATCH)
return ret;
local_lock_irqsave(&memcg_stock.stock_lock, flags);
stock = this_cpu_ptr(&memcg_stock);
if (memcg == READ_ONCE(stock->cached) && stock->nr_pages >= nr_pages) {
stock->nr_pages -= nr_pages;
ret = true;
}
local_unlock_irqrestore(&memcg_stock.stock_lock, flags);
return ret;
}
/*
* Returns stocks cached in percpu and reset cached information.
*/
static void drain_stock(struct memcg_stock_pcp *stock)
{
struct mem_cgroup *old = READ_ONCE(stock->cached);
if (!old)
return;
if (stock->nr_pages) {
page_counter_uncharge(&old->memory, stock->nr_pages);
if (do_memsw_account())
page_counter_uncharge(&old->memsw, stock->nr_pages);
stock->nr_pages = 0;
}
css_put(&old->css);
WRITE_ONCE(stock->cached, NULL);
}
static void drain_local_stock(struct work_struct *dummy)
{
struct memcg_stock_pcp *stock;
struct obj_cgroup *old = NULL;
unsigned long flags;
/*
* The only protection from cpu hotplug (memcg_hotplug_cpu_dead) vs.
* drain_stock races is that we always operate on local CPU stock
* here with IRQ disabled
*/
local_lock_irqsave(&memcg_stock.stock_lock, flags);
stock = this_cpu_ptr(&memcg_stock);
old = drain_obj_stock(stock);
drain_stock(stock);
clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags);
local_unlock_irqrestore(&memcg_stock.stock_lock, flags);
if (old)
obj_cgroup_put(old);
}
/*
* Cache charges(val) to local per_cpu area.
* This will be consumed by consume_stock() function, later.
*/
static void __refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
{
struct memcg_stock_pcp *stock;
stock = this_cpu_ptr(&memcg_stock);
if (READ_ONCE(stock->cached) != memcg) { /* reset if necessary */
drain_stock(stock);
css_get(&memcg->css);
WRITE_ONCE(stock->cached, memcg);
}
stock->nr_pages += nr_pages;
if (stock->nr_pages > MEMCG_CHARGE_BATCH)
drain_stock(stock);
}
static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
{
unsigned long flags;
local_lock_irqsave(&memcg_stock.stock_lock, flags);
__refill_stock(memcg, nr_pages);
local_unlock_irqrestore(&memcg_stock.stock_lock, flags);
}
/*
* Drains all per-CPU charge caches for given root_memcg resp. subtree
* of the hierarchy under it.
*/
static void drain_all_stock(struct mem_cgroup *root_memcg)
{
int cpu, curcpu;
/* If someone's already draining, avoid adding running more workers. */
if (!mutex_trylock(&percpu_charge_mutex))
return;
/*
* Notify other cpus that system-wide "drain" is running
* We do not care about races with the cpu hotplug because cpu down
* as well as workers from this path always operate on the local
* per-cpu data. CPU up doesn't touch memcg_stock at all.
*/
migrate_disable();
curcpu = smp_processor_id();
for_each_online_cpu(cpu) {
struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
struct mem_cgroup *memcg;
bool flush = false;
rcu_read_lock();
memcg = READ_ONCE(stock->cached);
if (memcg && stock->nr_pages &&
mem_cgroup_is_descendant(memcg, root_memcg))
flush = true;
else if (obj_stock_flush_required(stock, root_memcg))
flush = true;
rcu_read_unlock();
if (flush &&
!test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) {
if (cpu == curcpu)
drain_local_stock(&stock->work);
else if (!cpu_is_isolated(cpu))
schedule_work_on(cpu, &stock->work);
}
}
migrate_enable();
mutex_unlock(&percpu_charge_mutex);
}
static int memcg_hotplug_cpu_dead(unsigned int cpu)
{
struct memcg_stock_pcp *stock;
stock = &per_cpu(memcg_stock, cpu);
drain_stock(stock);
return 0;
}
static unsigned long reclaim_high(struct mem_cgroup *memcg,
unsigned int nr_pages,
gfp_t gfp_mask)
{
unsigned long nr_reclaimed = 0;
do {
unsigned long pflags;
if (page_counter_read(&memcg->memory) <=
READ_ONCE(memcg->memory.high))
continue;
memcg_memory_event(memcg, MEMCG_HIGH);
psi_memstall_enter(&pflags);
nr_reclaimed += try_to_free_mem_cgroup_pages(memcg, nr_pages,
gfp_mask,
MEMCG_RECLAIM_MAY_SWAP);
psi_memstall_leave(&pflags);
} while ((memcg = parent_mem_cgroup(memcg)) &&
!mem_cgroup_is_root(memcg));
return nr_reclaimed;
}
static void high_work_func(struct work_struct *work)
{
struct mem_cgroup *memcg;
memcg = container_of(work, struct mem_cgroup, high_work);
reclaim_high(memcg, MEMCG_CHARGE_BATCH, GFP_KERNEL);
}
/*
* Clamp the maximum sleep time per allocation batch to 2 seconds. This is
* enough to still cause a significant slowdown in most cases, while still
* allowing diagnostics and tracing to proceed without becoming stuck.
*/
#define MEMCG_MAX_HIGH_DELAY_JIFFIES (2UL*HZ)
/*
* When calculating the delay, we use these either side of the exponentiation to
* maintain precision and scale to a reasonable number of jiffies (see the table
* below.
*
* - MEMCG_DELAY_PRECISION_SHIFT: Extra precision bits while translating the
* overage ratio to a delay.
* - MEMCG_DELAY_SCALING_SHIFT: The number of bits to scale down the
* proposed penalty in order to reduce to a reasonable number of jiffies, and
* to produce a reasonable delay curve.
*
* MEMCG_DELAY_SCALING_SHIFT just happens to be a number that produces a
* reasonable delay curve compared to precision-adjusted overage, not
* penalising heavily at first, but still making sure that growth beyond the
* limit penalises misbehaviour cgroups by slowing them down exponentially. For
* example, with a high of 100 megabytes:
*
* +-------+------------------------+
* | usage | time to allocate in ms |
* +-------+------------------------+
* | 100M | 0 |
* | 101M | 6 |
* | 102M | 25 |
* | 103M | 57 |
* | 104M | 102 |
* | 105M | 159 |
* | 106M | 230 |
* | 107M | 313 |
* | 108M | 409 |
* | 109M | 518 |
* | 110M | 639 |
* | 111M | 774 |
* | 112M | 921 |
* | 113M | 1081 |
* | 114M | 1254 |
* | 115M | 1439 |
* | 116M | 1638 |
* | 117M | 1849 |
* | 118M | 2000 |
* | 119M | 2000 |
* | 120M | 2000 |
* +-------+------------------------+
*/
#define MEMCG_DELAY_PRECISION_SHIFT 20
#define MEMCG_DELAY_SCALING_SHIFT 14
static u64 calculate_overage(unsigned long usage, unsigned long high)
{
u64 overage;
if (usage <= high)
return 0;
/*
* Prevent division by 0 in overage calculation by acting as if
* it was a threshold of 1 page
*/
high = max(high, 1UL);
overage = usage - high;
overage <<= MEMCG_DELAY_PRECISION_SHIFT;
return div64_u64(overage, high);
}
static u64 mem_find_max_overage(struct mem_cgroup *memcg)
{
u64 overage, max_overage = 0;
do {
overage = calculate_overage(page_counter_read(&memcg->memory),
READ_ONCE(memcg->memory.high));
max_overage = max(overage, max_overage);
} while ((memcg = parent_mem_cgroup(memcg)) &&
!mem_cgroup_is_root(memcg));
return max_overage;
}
static u64 swap_find_max_overage(struct mem_cgroup *memcg)
{
u64 overage, max_overage = 0;
do {
overage = calculate_overage(page_counter_read(&memcg->swap),
READ_ONCE(memcg->swap.high));
if (overage)
memcg_memory_event(memcg, MEMCG_SWAP_HIGH);
max_overage = max(overage, max_overage);
} while ((memcg = parent_mem_cgroup(memcg)) &&
!mem_cgroup_is_root(memcg));
return max_overage;
}
/*
* Get the number of jiffies that we should penalise a mischievous cgroup which
* is exceeding its memory.high by checking both it and its ancestors.
*/
static unsigned long calculate_high_delay(struct mem_cgroup *memcg,
unsigned int nr_pages,
u64 max_overage)
{
unsigned long penalty_jiffies;
if (!max_overage)
return 0;
/*
* We use overage compared to memory.high to calculate the number of
* jiffies to sleep (penalty_jiffies). Ideally this value should be
* fairly lenient on small overages, and increasingly harsh when the
* memcg in question makes it clear that it has no intention of stopping
* its crazy behaviour, so we exponentially increase the delay based on
* overage amount.
*/
penalty_jiffies = max_overage * max_overage * HZ;
penalty_jiffies >>= MEMCG_DELAY_PRECISION_SHIFT;
penalty_jiffies >>= MEMCG_DELAY_SCALING_SHIFT;
/*
* Factor in the task's own contribution to the overage, such that four
* N-sized allocations are throttled approximately the same as one
* 4N-sized allocation.
*
* MEMCG_CHARGE_BATCH pages is nominal, so work out how much smaller or
* larger the current charge patch is than that.
*/
return penalty_jiffies * nr_pages / MEMCG_CHARGE_BATCH;
}
/*
* Scheduled by try_charge() to be executed from the userland return path
* and reclaims memory over the high limit.
*/
void mem_cgroup_handle_over_high(gfp_t gfp_mask)
{
unsigned long penalty_jiffies;
unsigned long pflags;
unsigned long nr_reclaimed;
unsigned int nr_pages = current->memcg_nr_pages_over_high;
int nr_retries = MAX_RECLAIM_RETRIES;
struct mem_cgroup *memcg;
bool in_retry = false;
if (likely(!nr_pages))
return;
memcg = get_mem_cgroup_from_mm(current->mm);
current->memcg_nr_pages_over_high = 0;
retry_reclaim:
/*
* The allocating task should reclaim at least the batch size, but for
* subsequent retries we only want to do what's necessary to prevent oom
* or breaching resource isolation.
*
* This is distinct from memory.max or page allocator behaviour because
* memory.high is currently batched, whereas memory.max and the page
* allocator run every time an allocation is made.
*/
nr_reclaimed = reclaim_high(memcg,
in_retry ? SWAP_CLUSTER_MAX : nr_pages,
gfp_mask);
/*
* memory.high is breached and reclaim is unable to keep up. Throttle
* allocators proactively to slow down excessive growth.
*/
penalty_jiffies = calculate_high_delay(memcg, nr_pages,
mem_find_max_overage(memcg));
penalty_jiffies += calculate_high_delay(memcg, nr_pages,
swap_find_max_overage(memcg));
/*
* Clamp the max delay per usermode return so as to still keep the
* application moving forwards and also permit diagnostics, albeit
* extremely slowly.
*/
penalty_jiffies = min(penalty_jiffies, MEMCG_MAX_HIGH_DELAY_JIFFIES);
/*
* Don't sleep if the amount of jiffies this memcg owes us is so low
* that it's not even worth doing, in an attempt to be nice to those who
* go only a small amount over their memory.high value and maybe haven't
* been aggressively reclaimed enough yet.
*/
if (penalty_jiffies <= HZ / 100)
goto out;
/*
* If reclaim is making forward progress but we're still over
* memory.high, we want to encourage that rather than doing allocator
* throttling.
*/
if (nr_reclaimed || nr_retries--) {
in_retry = true;
goto retry_reclaim;
}
/*
* If we exit early, we're guaranteed to die (since
* schedule_timeout_killable sets TASK_KILLABLE). This means we don't
* need to account for any ill-begotten jiffies to pay them off later.
*/
psi_memstall_enter(&pflags);
schedule_timeout_killable(penalty_jiffies);
psi_memstall_leave(&pflags);
out:
css_put(&memcg->css);
}
static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask,
unsigned int nr_pages)
{
unsigned int batch = max(MEMCG_CHARGE_BATCH, nr_pages);
int nr_retries = MAX_RECLAIM_RETRIES;
struct mem_cgroup *mem_over_limit;
struct page_counter *counter;
unsigned long nr_reclaimed;
bool passed_oom = false;
unsigned int reclaim_options = MEMCG_RECLAIM_MAY_SWAP;
bool drained = false;
bool raised_max_event = false;
unsigned long pflags;
retry:
if (consume_stock(memcg, nr_pages))
return 0;
if (!do_memsw_account() ||
page_counter_try_charge(&memcg->memsw, batch, &counter)) {
if (page_counter_try_charge(&memcg->memory, batch, &counter))
goto done_restock;
if (do_memsw_account())
page_counter_uncharge(&memcg->memsw, batch);
mem_over_limit = mem_cgroup_from_counter(counter, memory);
} else {
mem_over_limit = mem_cgroup_from_counter(counter, memsw);
reclaim_options &= ~MEMCG_RECLAIM_MAY_SWAP;
}
if (batch > nr_pages) {
batch = nr_pages;
goto retry;
}
/*
* Prevent unbounded recursion when reclaim operations need to
* allocate memory. This might exceed the limits temporarily,
* but we prefer facilitating memory reclaim and getting back
* under the limit over triggering OOM kills in these cases.
*/
if (unlikely(current->flags & PF_MEMALLOC))
goto force;
if (unlikely(task_in_memcg_oom(current)))
goto nomem;
if (!gfpflags_allow_blocking(gfp_mask))
goto nomem;
memcg_memory_event(mem_over_limit, MEMCG_MAX);
raised_max_event = true;
psi_memstall_enter(&pflags);
nr_reclaimed = try_to_free_mem_cgroup_pages(mem_over_limit, nr_pages,
gfp_mask, reclaim_options);
psi_memstall_leave(&pflags);
if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
goto retry;
if (!drained) {
drain_all_stock(mem_over_limit);
drained = true;
goto retry;
}
if (gfp_mask & __GFP_NORETRY)
goto nomem;
/*
* Even though the limit is exceeded at this point, reclaim
* may have been able to free some pages. Retry the charge
* before killing the task.
*
* Only for regular pages, though: huge pages are rather
* unlikely to succeed so close to the limit, and we fall back
* to regular pages anyway in case of failure.
*/
if (nr_reclaimed && nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER))
goto retry;
/*
* At task move, charge accounts can be doubly counted. So, it's
* better to wait until the end of task_move if something is going on.
*/
if (mem_cgroup_wait_acct_move(mem_over_limit))
goto retry;
if (nr_retries--)
goto retry;
if (gfp_mask & __GFP_RETRY_MAYFAIL)
goto nomem;
/* Avoid endless loop for tasks bypassed by the oom killer */
if (passed_oom && task_is_dying())
goto nomem;
/*
* keep retrying as long as the memcg oom killer is able to make
* a forward progress or bypass the charge if the oom killer
* couldn't make any progress.
*/
if (mem_cgroup_oom(mem_over_limit, gfp_mask,
get_order(nr_pages * PAGE_SIZE))) {
passed_oom = true;
nr_retries = MAX_RECLAIM_RETRIES;
goto retry;
}
nomem:
/*
* Memcg doesn't have a dedicated reserve for atomic
* allocations. But like the global atomic pool, we need to
* put the burden of reclaim on regular allocation requests
* and let these go through as privileged allocations.
*/
if (!(gfp_mask & (__GFP_NOFAIL | __GFP_HIGH)))
return -ENOMEM;
force:
/*
* If the allocation has to be enforced, don't forget to raise
* a MEMCG_MAX event.
*/
if (!raised_max_event)
memcg_memory_event(mem_over_limit, MEMCG_MAX);
/*
* The allocation either can't fail or will lead to more memory
* being freed very soon. Allow memory usage go over the limit
* temporarily by force charging it.
*/
page_counter_charge(&memcg->memory, nr_pages);
if (do_memsw_account())
page_counter_charge(&memcg->memsw, nr_pages);
return 0;
done_restock:
if (batch > nr_pages)
refill_stock(memcg, batch - nr_pages);
/*
* If the hierarchy is above the normal consumption range, schedule
* reclaim on returning to userland. We can perform reclaim here
* if __GFP_RECLAIM but let's always punt for simplicity and so that
* GFP_KERNEL can consistently be used during reclaim. @memcg is
* not recorded as it most likely matches current's and won't
* change in the meantime. As high limit is checked again before
* reclaim, the cost of mismatch is negligible.
*/
do {
bool mem_high, swap_high;
mem_high = page_counter_read(&memcg->memory) >
READ_ONCE(memcg->memory.high);
swap_high = page_counter_read(&memcg->swap) >
READ_ONCE(memcg->swap.high);
/* Don't bother a random interrupted task */
if (!in_task()) {
if (mem_high) {
schedule_work(&memcg->high_work);
break;
}
continue;
}
if (mem_high || swap_high) {
/*
* The allocating tasks in this cgroup will need to do
* reclaim or be throttled to prevent further growth
* of the memory or swap footprints.
*
* Target some best-effort fairness between the tasks,
* and distribute reclaim work and delay penalties
* based on how much each task is actually allocating.
*/
current->memcg_nr_pages_over_high += batch;
set_notify_resume(current);
break;
}
} while ((memcg = parent_mem_cgroup(memcg)));
if (current->memcg_nr_pages_over_high > MEMCG_CHARGE_BATCH &&
!(current->flags & PF_MEMALLOC) &&
gfpflags_allow_blocking(gfp_mask)) {
mem_cgroup_handle_over_high(gfp_mask);
}
return 0;
}
static inline int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
unsigned int nr_pages)
{
if (mem_cgroup_is_root(memcg))
return 0;
return try_charge_memcg(memcg, gfp_mask, nr_pages);
}
static inline void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages)
{
if (mem_cgroup_is_root(memcg))
return;
page_counter_uncharge(&memcg->memory, nr_pages);
if (do_memsw_account())
page_counter_uncharge(&memcg->memsw, nr_pages);
}
static void commit_charge(struct folio *folio, struct mem_cgroup *memcg)
{
VM_BUG_ON_FOLIO(folio_memcg(folio), folio);
/*
* Any of the following ensures page's memcg stability:
*
* - the page lock
* - LRU isolation
* - folio_memcg_lock()
* - exclusive reference
* - mem_cgroup_trylock_pages()
*/
folio->memcg_data = (unsigned long)memcg;
}
#ifdef CONFIG_MEMCG_KMEM
/*
* The allocated objcg pointers array is not accounted directly.
* Moreover, it should not come from DMA buffer and is not readily
* reclaimable. So those GFP bits should be masked off.
*/
#define OBJCGS_CLEAR_MASK (__GFP_DMA | __GFP_RECLAIMABLE | __GFP_ACCOUNT)
/*
* mod_objcg_mlstate() may be called with irq enabled, so
* mod_memcg_lruvec_state() should be used.
*/
static inline void mod_objcg_mlstate(struct obj_cgroup *objcg,
struct pglist_data *pgdat,
enum node_stat_item idx, int nr)
{
struct mem_cgroup *memcg;
struct lruvec *lruvec;
rcu_read_lock();
memcg = obj_cgroup_memcg(objcg);
lruvec = mem_cgroup_lruvec(memcg, pgdat);
mod_memcg_lruvec_state(lruvec, idx, nr);
rcu_read_unlock();
}
int memcg_alloc_slab_cgroups(struct slab *slab, struct kmem_cache *s,
gfp_t gfp, bool new_slab)
{
unsigned int objects = objs_per_slab(s, slab);
unsigned long memcg_data;
void *vec;
gfp &= ~OBJCGS_CLEAR_MASK;
vec = kcalloc_node(objects, sizeof(struct obj_cgroup *), gfp,
slab_nid(slab));
if (!vec)
return -ENOMEM;
memcg_data = (unsigned long) vec | MEMCG_DATA_OBJCGS;
if (new_slab) {
/*
* If the slab is brand new and nobody can yet access its
* memcg_data, no synchronization is required and memcg_data can
* be simply assigned.
*/
slab->memcg_data = memcg_data;
} else if (cmpxchg(&slab->memcg_data, 0, memcg_data)) {
/*
* If the slab is already in use, somebody can allocate and
* assign obj_cgroups in parallel. In this case the existing
* objcg vector should be reused.
*/
kfree(vec);
return 0;
}
kmemleak_not_leak(vec);
return 0;
}
static __always_inline
struct mem_cgroup *mem_cgroup_from_obj_folio(struct folio *folio, void *p)
{
/*
* Slab objects are accounted individually, not per-page.
* Memcg membership data for each individual object is saved in
* slab->memcg_data.
*/
if (folio_test_slab(folio)) {
struct obj_cgroup **objcgs;
struct slab *slab;
unsigned int off;
slab = folio_slab(folio);
objcgs = slab_objcgs(slab);
if (!objcgs)
return NULL;
off = obj_to_index(slab->slab_cache, slab, p);
if (objcgs[off])
return obj_cgroup_memcg(objcgs[off]);
return NULL;
}
/*
* folio_memcg_check() is used here, because in theory we can encounter
* a folio where the slab flag has been cleared already, but
* slab->memcg_data has not been freed yet
* folio_memcg_check() will guarantee that a proper memory
* cgroup pointer or NULL will be returned.
*/
return folio_memcg_check(folio);
}
/*
* Returns a pointer to the memory cgroup to which the kernel object is charged.
*
* A passed kernel object can be a slab object, vmalloc object or a generic
* kernel page, so different mechanisms for getting the memory cgroup pointer
* should be used.
*
* In certain cases (e.g. kernel stacks or large kmallocs with SLUB) the caller
* can not know for sure how the kernel object is implemented.
* mem_cgroup_from_obj() can be safely used in such cases.
*
* The caller must ensure the memcg lifetime, e.g. by taking rcu_read_lock(),
* cgroup_mutex, etc.
*/
struct mem_cgroup *mem_cgroup_from_obj(void *p)
{
struct folio *folio;
if (mem_cgroup_disabled())
return NULL;
if (unlikely(is_vmalloc_addr(p)))
folio = page_folio(vmalloc_to_page(p));
else
folio = virt_to_folio(p);
return mem_cgroup_from_obj_folio(folio, p);
}
/*
* Returns a pointer to the memory cgroup to which the kernel object is charged.
* Similar to mem_cgroup_from_obj(), but faster and not suitable for objects,
* allocated using vmalloc().
*
* A passed kernel object must be a slab object or a generic kernel page.
*
* The caller must ensure the memcg lifetime, e.g. by taking rcu_read_lock(),
* cgroup_mutex, etc.
*/
struct mem_cgroup *mem_cgroup_from_slab_obj(void *p)
{
if (mem_cgroup_disabled())
return NULL;
return mem_cgroup_from_obj_folio(virt_to_folio(p), p);
}
static struct obj_cgroup *__get_obj_cgroup_from_memcg(struct mem_cgroup *memcg)
{
struct obj_cgroup *objcg = NULL;
for (; !mem_cgroup_is_root(memcg); memcg = parent_mem_cgroup(memcg)) {
objcg = rcu_dereference(memcg->objcg);
if (objcg && obj_cgroup_tryget(objcg))
break;
objcg = NULL;
}
return objcg;
}
__always_inline struct obj_cgroup *get_obj_cgroup_from_current(void)
{
struct obj_cgroup *objcg = NULL;
struct mem_cgroup *memcg;
if (memcg_kmem_bypass())
return NULL;
rcu_read_lock();
if (unlikely(active_memcg()))
memcg = active_memcg();
else
memcg = mem_cgroup_from_task(current);
objcg = __get_obj_cgroup_from_memcg(memcg);
rcu_read_unlock();
return objcg;
}
struct obj_cgroup *get_obj_cgroup_from_folio(struct folio *folio)
{
struct obj_cgroup *objcg;
if (!memcg_kmem_online())
return NULL;
if (folio_memcg_kmem(folio)) {
objcg = __folio_objcg(folio);
obj_cgroup_get(objcg);
} else {
struct mem_cgroup *memcg;
rcu_read_lock();
memcg = __folio_memcg(folio);
if (memcg)
objcg = __get_obj_cgroup_from_memcg(memcg);
else
objcg = NULL;
rcu_read_unlock();
}
return objcg;
}
static void memcg_account_kmem(struct mem_cgroup *memcg, int nr_pages)
{
mod_memcg_state(memcg, MEMCG_KMEM, nr_pages);
if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) {
if (nr_pages > 0)
page_counter_charge(&memcg->kmem, nr_pages);
else
page_counter_uncharge(&memcg->kmem, -nr_pages);
}
}
/*
* obj_cgroup_uncharge_pages: uncharge a number of kernel pages from a objcg
* @objcg: object cgroup to uncharge
* @nr_pages: number of pages to uncharge
*/
static void obj_cgroup_uncharge_pages(struct obj_cgroup *objcg,
unsigned int nr_pages)
{
struct mem_cgroup *memcg;
memcg = get_mem_cgroup_from_objcg(objcg);
memcg_account_kmem(memcg, -nr_pages);
refill_stock(memcg, nr_pages);
css_put(&memcg->css);
}
/*
* obj_cgroup_charge_pages: charge a number of kernel pages to a objcg
* @objcg: object cgroup to charge
* @gfp: reclaim mode
* @nr_pages: number of pages to charge
*
* Returns 0 on success, an error code on failure.
*/
static int obj_cgroup_charge_pages(struct obj_cgroup *objcg, gfp_t gfp,
unsigned int nr_pages)
{
struct mem_cgroup *memcg;
int ret;
memcg = get_mem_cgroup_from_objcg(objcg);
ret = try_charge_memcg(memcg, gfp, nr_pages);
if (ret)
goto out;
memcg_account_kmem(memcg, nr_pages);
out:
css_put(&memcg->css);
return ret;
}
/**
* __memcg_kmem_charge_page: charge a kmem page to the current memory cgroup
* @page: page to charge
* @gfp: reclaim mode
* @order: allocation order
*
* Returns 0 on success, an error code on failure.
*/
int __memcg_kmem_charge_page(struct page *page, gfp_t gfp, int order)
{
struct obj_cgroup *objcg;
int ret = 0;
objcg = get_obj_cgroup_from_current();
if (objcg) {
ret = obj_cgroup_charge_pages(objcg, gfp, 1 << order);
if (!ret) {
page->memcg_data = (unsigned long)objcg |
MEMCG_DATA_KMEM;
return 0;
}
obj_cgroup_put(objcg);
}
return ret;
}
/**
* __memcg_kmem_uncharge_page: uncharge a kmem page
* @page: page to uncharge
* @order: allocation order
*/
void __memcg_kmem_uncharge_page(struct page *page, int order)
{
struct folio *folio = page_folio(page);
struct obj_cgroup *objcg;
unsigned int nr_pages = 1 << order;
if (!folio_memcg_kmem(folio))
return;
objcg = __folio_objcg(folio);
obj_cgroup_uncharge_pages(objcg, nr_pages);
folio->memcg_data = 0;
obj_cgroup_put(objcg);
}
void mod_objcg_state(struct obj_cgroup *objcg, struct pglist_data *pgdat,
enum node_stat_item idx, int nr)
{
struct memcg_stock_pcp *stock;
struct obj_cgroup *old = NULL;
unsigned long flags;
int *bytes;
local_lock_irqsave(&memcg_stock.stock_lock, flags);
stock = this_cpu_ptr(&memcg_stock);
/*
* Save vmstat data in stock and skip vmstat array update unless
* accumulating over a page of vmstat data or when pgdat or idx
* changes.
*/
if (READ_ONCE(stock->cached_objcg) != objcg) {
old = drain_obj_stock(stock);
obj_cgroup_get(objcg);
stock->nr_bytes = atomic_read(&objcg->nr_charged_bytes)
? atomic_xchg(&objcg->nr_charged_bytes, 0) : 0;
WRITE_ONCE(stock->cached_objcg, objcg);
stock->cached_pgdat = pgdat;
} else if (stock->cached_pgdat != pgdat) {
/* Flush the existing cached vmstat data */
struct pglist_data *oldpg = stock->cached_pgdat;
if (stock->nr_slab_reclaimable_b) {
mod_objcg_mlstate(objcg, oldpg, NR_SLAB_RECLAIMABLE_B,
stock->nr_slab_reclaimable_b);
stock->nr_slab_reclaimable_b = 0;
}
if (stock->nr_slab_unreclaimable_b) {
mod_objcg_mlstate(objcg, oldpg, NR_SLAB_UNRECLAIMABLE_B,
stock->nr_slab_unreclaimable_b);
stock->nr_slab_unreclaimable_b = 0;
}
stock->cached_pgdat = pgdat;
}
bytes = (idx == NR_SLAB_RECLAIMABLE_B) ? &stock->nr_slab_reclaimable_b
: &stock->nr_slab_unreclaimable_b;
/*
* Even for large object >= PAGE_SIZE, the vmstat data will still be
* cached locally at least once before pushing it out.
*/
if (!*bytes) {
*bytes = nr;
nr = 0;
} else {
*bytes += nr;
if (abs(*bytes) > PAGE_SIZE) {
nr = *bytes;
*bytes = 0;
} else {
nr = 0;
}
}
if (nr)
mod_objcg_mlstate(objcg, pgdat, idx, nr);
local_unlock_irqrestore(&memcg_stock.stock_lock, flags);
if (old)
obj_cgroup_put(old);
}
static bool consume_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes)
{
struct memcg_stock_pcp *stock;
unsigned long flags;
bool ret = false;
local_lock_irqsave(&memcg_stock.stock_lock, flags);
stock = this_cpu_ptr(&memcg_stock);
if (objcg == READ_ONCE(stock->cached_objcg) && stock->nr_bytes >= nr_bytes) {
stock->nr_bytes -= nr_bytes;
ret = true;
}
local_unlock_irqrestore(&memcg_stock.stock_lock, flags);
return ret;
}
static struct obj_cgroup *drain_obj_stock(struct memcg_stock_pcp *stock)
{
struct obj_cgroup *old = READ_ONCE(stock->cached_objcg);
if (!old)
return NULL;
if (stock->nr_bytes) {
unsigned int nr_pages = stock->nr_bytes >> PAGE_SHIFT;
unsigned int nr_bytes = stock->nr_bytes & (PAGE_SIZE - 1);
if (nr_pages) {
struct mem_cgroup *memcg;
memcg = get_mem_cgroup_from_objcg(old);
memcg_account_kmem(memcg, -nr_pages);
__refill_stock(memcg, nr_pages);
css_put(&memcg->css);
}
/*
* The leftover is flushed to the centralized per-memcg value.
* On the next attempt to refill obj stock it will be moved
* to a per-cpu stock (probably, on an other CPU), see
* refill_obj_stock().
*
* How often it's flushed is a trade-off between the memory
* limit enforcement accuracy and potential CPU contention,
* so it might be changed in the future.
*/
atomic_add(nr_bytes, &old->nr_charged_bytes);
stock->nr_bytes = 0;
}
/*
* Flush the vmstat data in current stock
*/
if (stock->nr_slab_reclaimable_b || stock->nr_slab_unreclaimable_b) {
if (stock->nr_slab_reclaimable_b) {
mod_objcg_mlstate(old, stock->cached_pgdat,
NR_SLAB_RECLAIMABLE_B,
stock->nr_slab_reclaimable_b);
stock->nr_slab_reclaimable_b = 0;
}
if (stock->nr_slab_unreclaimable_b) {
mod_objcg_mlstate(old, stock->cached_pgdat,
NR_SLAB_UNRECLAIMABLE_B,
stock->nr_slab_unreclaimable_b);
stock->nr_slab_unreclaimable_b = 0;
}
stock->cached_pgdat = NULL;
}
WRITE_ONCE(stock->cached_objcg, NULL);
/*
* The `old' objects needs to be released by the caller via
* obj_cgroup_put() outside of memcg_stock_pcp::stock_lock.
*/
return old;
}
static bool obj_stock_flush_required(struct memcg_stock_pcp *stock,
struct mem_cgroup *root_memcg)
{
struct obj_cgroup *objcg = READ_ONCE(stock->cached_objcg);
struct mem_cgroup *memcg;
if (objcg) {
memcg = obj_cgroup_memcg(objcg);
if (memcg && mem_cgroup_is_descendant(memcg, root_memcg))
return true;
}
return false;
}
static void refill_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes,
bool allow_uncharge)
{
struct memcg_stock_pcp *stock;
struct obj_cgroup *old = NULL;
unsigned long flags;
unsigned int nr_pages = 0;
local_lock_irqsave(&memcg_stock.stock_lock, flags);
stock = this_cpu_ptr(&memcg_stock);
if (READ_ONCE(stock->cached_objcg) != objcg) { /* reset if necessary */
old = drain_obj_stock(stock);
obj_cgroup_get(objcg);
WRITE_ONCE(stock->cached_objcg, objcg);
stock->nr_bytes = atomic_read(&objcg->nr_charged_bytes)
? atomic_xchg(&objcg->nr_charged_bytes, 0) : 0;
allow_uncharge = true; /* Allow uncharge when objcg changes */
}
stock->nr_bytes += nr_bytes;
if (allow_uncharge && (stock->nr_bytes > PAGE_SIZE)) {
nr_pages = stock->nr_bytes >> PAGE_SHIFT;
stock->nr_bytes &= (PAGE_SIZE - 1);
}
local_unlock_irqrestore(&memcg_stock.stock_lock, flags);
if (old)
obj_cgroup_put(old);
if (nr_pages)
obj_cgroup_uncharge_pages(objcg, nr_pages);
}
int obj_cgroup_charge(struct obj_cgroup *objcg, gfp_t gfp, size_t size)
{
unsigned int nr_pages, nr_bytes;
int ret;
if (consume_obj_stock(objcg, size))
return 0;
/*
* In theory, objcg->nr_charged_bytes can have enough
* pre-charged bytes to satisfy the allocation. However,
* flushing objcg->nr_charged_bytes requires two atomic
* operations, and objcg->nr_charged_bytes can't be big.
* The shared objcg->nr_charged_bytes can also become a
* performance bottleneck if all tasks of the same memcg are
* trying to update it. So it's better to ignore it and try
* grab some new pages. The stock's nr_bytes will be flushed to
* objcg->nr_charged_bytes later on when objcg changes.
*
* The stock's nr_bytes may contain enough pre-charged bytes
* to allow one less page from being charged, but we can't rely
* on the pre-charged bytes not being changed outside of
* consume_obj_stock() or refill_obj_stock(). So ignore those
* pre-charged bytes as well when charging pages. To avoid a
* page uncharge right after a page charge, we set the
* allow_uncharge flag to false when calling refill_obj_stock()
* to temporarily allow the pre-charged bytes to exceed the page
* size limit. The maximum reachable value of the pre-charged
* bytes is (sizeof(object) + PAGE_SIZE - 2) if there is no data
* race.
*/
nr_pages = size >> PAGE_SHIFT;
nr_bytes = size & (PAGE_SIZE - 1);
if (nr_bytes)
nr_pages += 1;
ret = obj_cgroup_charge_pages(objcg, gfp, nr_pages);
if (!ret && nr_bytes)
refill_obj_stock(objcg, PAGE_SIZE - nr_bytes, false);
return ret;
}
void obj_cgroup_uncharge(struct obj_cgroup *objcg, size_t size)
{
refill_obj_stock(objcg, size, true);
}
#endif /* CONFIG_MEMCG_KMEM */
/*
* Because page_memcg(head) is not set on tails, set it now.
*/
void split_page_memcg(struct page *head, unsigned int nr)
{
struct folio *folio = page_folio(head);
struct mem_cgroup *memcg = folio_memcg(folio);
int i;
if (mem_cgroup_disabled() || !memcg)
return;
for (i = 1; i < nr; i++)
folio_page(folio, i)->memcg_data = folio->memcg_data;
if (folio_memcg_kmem(folio))
obj_cgroup_get_many(__folio_objcg(folio), nr - 1);
else
css_get_many(&memcg->css, nr - 1);
}
#ifdef CONFIG_SWAP
/**
* mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
* @entry: swap entry to be moved
* @from: mem_cgroup which the entry is moved from
* @to: mem_cgroup which the entry is moved to
*
* It succeeds only when the swap_cgroup's record for this entry is the same
* as the mem_cgroup's id of @from.
*
* Returns 0 on success, -EINVAL on failure.
*
* The caller must have charged to @to, IOW, called page_counter_charge() about
* both res and memsw, and called css_get().
*/
static int mem_cgroup_move_swap_account(swp_entry_t entry,
struct mem_cgroup *from, struct mem_cgroup *to)
{
unsigned short old_id, new_id;
old_id = mem_cgroup_id(from);
new_id = mem_cgroup_id(to);
if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) {
mod_memcg_state(from, MEMCG_SWAP, -1);
mod_memcg_state(to, MEMCG_SWAP, 1);
return 0;
}
return -EINVAL;
}
#else
static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
struct mem_cgroup *from, struct mem_cgroup *to)
{
return -EINVAL;
}
#endif
static DEFINE_MUTEX(memcg_max_mutex);
static int mem_cgroup_resize_max(struct mem_cgroup *memcg,
unsigned long max, bool memsw)
{
bool enlarge = false;
bool drained = false;
int ret;
bool limits_invariant;
struct page_counter *counter = memsw ? &memcg->memsw : &memcg->memory;
do {
if (signal_pending(current)) {
ret = -EINTR;
break;
}
mutex_lock(&memcg_max_mutex);
/*
* Make sure that the new limit (memsw or memory limit) doesn't
* break our basic invariant rule memory.max <= memsw.max.
*/
limits_invariant = memsw ? max >= READ_ONCE(memcg->memory.max) :
max <= memcg->memsw.max;
if (!limits_invariant) {
mutex_unlock(&memcg_max_mutex);
ret = -EINVAL;
break;
}
if (max > counter->max)
enlarge = true;
ret = page_counter_set_max(counter, max);
mutex_unlock(&memcg_max_mutex);
if (!ret)
break;
if (!drained) {
drain_all_stock(memcg);
drained = true;
continue;
}
if (!try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL,
memsw ? 0 : MEMCG_RECLAIM_MAY_SWAP)) {
ret = -EBUSY;
break;
}
} while (true);
if (!ret && enlarge)
memcg_oom_recover(memcg);
return ret;
}
unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
gfp_t gfp_mask,
unsigned long *total_scanned)
{
unsigned long nr_reclaimed = 0;
struct mem_cgroup_per_node *mz, *next_mz = NULL;
unsigned long reclaimed;
int loop = 0;
struct mem_cgroup_tree_per_node *mctz;
unsigned long excess;
if (lru_gen_enabled())
return 0;
if (order > 0)
return 0;
mctz = soft_limit_tree.rb_tree_per_node[pgdat->node_id];
/*
* Do not even bother to check the largest node if the root
* is empty. Do it lockless to prevent lock bouncing. Races
* are acceptable as soft limit is best effort anyway.
*/
if (!mctz || RB_EMPTY_ROOT(&mctz->rb_root))
return 0;
/*
* This loop can run a while, specially if mem_cgroup's continuously
* keep exceeding their soft limit and putting the system under
* pressure
*/
do {
if (next_mz)
mz = next_mz;
else
mz = mem_cgroup_largest_soft_limit_node(mctz);
if (!mz)
break;
reclaimed = mem_cgroup_soft_reclaim(mz->memcg, pgdat,
gfp_mask, total_scanned);
nr_reclaimed += reclaimed;
spin_lock_irq(&mctz->lock);
/*
* If we failed to reclaim anything from this memory cgroup
* it is time to move on to the next cgroup
*/
next_mz = NULL;
if (!reclaimed)
next_mz = __mem_cgroup_largest_soft_limit_node(mctz);
excess = soft_limit_excess(mz->memcg);
/*
* One school of thought says that we should not add
* back the node to the tree if reclaim returns 0.
* But our reclaim could return 0, simply because due
* to priority we are exposing a smaller subset of
* memory to reclaim from. Consider this as a longer
* term TODO.
*/
/* If excess == 0, no tree ops */
__mem_cgroup_insert_exceeded(mz, mctz, excess);
spin_unlock_irq(&mctz->lock);
css_put(&mz->memcg->css);
loop++;
/*
* Could not reclaim anything and there are no more
* mem cgroups to try or we seem to be looping without
* reclaiming anything.
*/
if (!nr_reclaimed &&
(next_mz == NULL ||
loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
break;
} while (!nr_reclaimed);
if (next_mz)
css_put(&next_mz->memcg->css);
return nr_reclaimed;
}
/*
* Reclaims as many pages from the given memcg as possible.
*
* Caller is responsible for holding css reference for memcg.
*/
static int mem_cgroup_force_empty(struct mem_cgroup *memcg)
{
int nr_retries = MAX_RECLAIM_RETRIES;
/* we call try-to-free pages for make this cgroup empty */
lru_add_drain_all();
drain_all_stock(memcg);
/* try to free all pages in this cgroup */
while (nr_retries && page_counter_read(&memcg->memory)) {
if (signal_pending(current))
return -EINTR;
if (!try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL,
MEMCG_RECLAIM_MAY_SWAP))
nr_retries--;
}
return 0;
}
static ssize_t mem_cgroup_force_empty_write(struct kernfs_open_file *of,
char *buf, size_t nbytes,
loff_t off)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
if (mem_cgroup_is_root(memcg))
return -EINVAL;
return mem_cgroup_force_empty(memcg) ?: nbytes;
}
static u64 mem_cgroup_hierarchy_read(struct cgroup_subsys_state *css,
struct cftype *cft)
{
return 1;
}
static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state *css,
struct cftype *cft, u64 val)
{
if (val == 1)
return 0;
pr_warn_once("Non-hierarchical mode is deprecated. "
"Please report your usecase to [email protected] if you "
"depend on this functionality.\n");
return -EINVAL;
}
static unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
{
unsigned long val;
if (mem_cgroup_is_root(memcg)) {
/*
* Approximate root's usage from global state. This isn't
* perfect, but the root usage was always an approximation.
*/
val = global_node_page_state(NR_FILE_PAGES) +
global_node_page_state(NR_ANON_MAPPED);
if (swap)
val += total_swap_pages - get_nr_swap_pages();
} else {
if (!swap)
val = page_counter_read(&memcg->memory);
else
val = page_counter_read(&memcg->memsw);
}
return val;
}
enum {
RES_USAGE,
RES_LIMIT,
RES_MAX_USAGE,
RES_FAILCNT,
RES_SOFT_LIMIT,
};
static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css,
struct cftype *cft)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
struct page_counter *counter;
switch (MEMFILE_TYPE(cft->private)) {
case _MEM:
counter = &memcg->memory;
break;
case _MEMSWAP:
counter = &memcg->memsw;
break;
case _KMEM:
counter = &memcg->kmem;
break;
case _TCP:
counter = &memcg->tcpmem;
break;
default:
BUG();
}
switch (MEMFILE_ATTR(cft->private)) {
case RES_USAGE:
if (counter == &memcg->memory)
return (u64)mem_cgroup_usage(memcg, false) * PAGE_SIZE;
if (counter == &memcg->memsw)
return (u64)mem_cgroup_usage(memcg, true) * PAGE_SIZE;
return (u64)page_counter_read(counter) * PAGE_SIZE;
case RES_LIMIT:
return (u64)counter->max * PAGE_SIZE;
case RES_MAX_USAGE:
return (u64)counter->watermark * PAGE_SIZE;
case RES_FAILCNT:
return counter->failcnt;
case RES_SOFT_LIMIT:
return (u64)READ_ONCE(memcg->soft_limit) * PAGE_SIZE;
default:
BUG();
}
}
/*
* This function doesn't do anything useful. Its only job is to provide a read
* handler for a file so that cgroup_file_mode() will add read permissions.
*/
static int mem_cgroup_dummy_seq_show(__always_unused struct seq_file *m,
__always_unused void *v)
{
return -EINVAL;
}
#ifdef CONFIG_MEMCG_KMEM
static int memcg_online_kmem(struct mem_cgroup *memcg)
{
struct obj_cgroup *objcg;
if (mem_cgroup_kmem_disabled())
return 0;
if (unlikely(mem_cgroup_is_root(memcg)))
return 0;
objcg = obj_cgroup_alloc();
if (!objcg)
return -ENOMEM;
objcg->memcg = memcg;
rcu_assign_pointer(memcg->objcg, objcg);
static_branch_enable(&memcg_kmem_online_key);
memcg->kmemcg_id = memcg->id.id;
return 0;
}
static void memcg_offline_kmem(struct mem_cgroup *memcg)
{
struct mem_cgroup *parent;
if (mem_cgroup_kmem_disabled())
return;
if (unlikely(mem_cgroup_is_root(memcg)))
return;
parent = parent_mem_cgroup(memcg);
if (!parent)
parent = root_mem_cgroup;
memcg_reparent_objcgs(memcg, parent);
/*
* After we have finished memcg_reparent_objcgs(), all list_lrus
* corresponding to this cgroup are guaranteed to remain empty.
* The ordering is imposed by list_lru_node->lock taken by
* memcg_reparent_list_lrus().
*/
memcg_reparent_list_lrus(memcg, parent);
}
#else
static int memcg_online_kmem(struct mem_cgroup *memcg)
{
return 0;
}
static void memcg_offline_kmem(struct mem_cgroup *memcg)
{
}
#endif /* CONFIG_MEMCG_KMEM */
static int memcg_update_tcp_max(struct mem_cgroup *memcg, unsigned long max)
{
int ret;
mutex_lock(&memcg_max_mutex);
ret = page_counter_set_max(&memcg->tcpmem, max);
if (ret)
goto out;
if (!memcg->tcpmem_active) {
/*
* The active flag needs to be written after the static_key
* update. This is what guarantees that the socket activation
* function is the last one to run. See mem_cgroup_sk_alloc()
* for details, and note that we don't mark any socket as
* belonging to this memcg until that flag is up.
*
* We need to do this, because static_keys will span multiple
* sites, but we can't control their order. If we mark a socket
* as accounted, but the accounting functions are not patched in
* yet, we'll lose accounting.
*
* We never race with the readers in mem_cgroup_sk_alloc(),
* because when this value change, the code to process it is not
* patched in yet.
*/
static_branch_inc(&memcg_sockets_enabled_key);
memcg->tcpmem_active = true;
}
out:
mutex_unlock(&memcg_max_mutex);
return ret;
}
/*
* The user of this function is...
* RES_LIMIT.
*/
static ssize_t mem_cgroup_write(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
unsigned long nr_pages;
int ret;
buf = strstrip(buf);
ret = page_counter_memparse(buf, "-1", &nr_pages);
if (ret)
return ret;
switch (MEMFILE_ATTR(of_cft(of)->private)) {
case RES_LIMIT:
if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
ret = -EINVAL;
break;
}
switch (MEMFILE_TYPE(of_cft(of)->private)) {
case _MEM:
ret = mem_cgroup_resize_max(memcg, nr_pages, false);
break;
case _MEMSWAP:
ret = mem_cgroup_resize_max(memcg, nr_pages, true);
break;
case _TCP:
ret = memcg_update_tcp_max(memcg, nr_pages);
break;
}
break;
case RES_SOFT_LIMIT:
if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
ret = -EOPNOTSUPP;
} else {
WRITE_ONCE(memcg->soft_limit, nr_pages);
ret = 0;
}
break;
}
return ret ?: nbytes;
}
static ssize_t mem_cgroup_reset(struct kernfs_open_file *of, char *buf,
size_t nbytes, loff_t off)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
struct page_counter *counter;
switch (MEMFILE_TYPE(of_cft(of)->private)) {
case _MEM:
counter = &memcg->memory;
break;
case _MEMSWAP:
counter = &memcg->memsw;
break;
case _KMEM:
counter = &memcg->kmem;
break;
case _TCP:
counter = &memcg->tcpmem;
break;
default:
BUG();
}
switch (MEMFILE_ATTR(of_cft(of)->private)) {
case RES_MAX_USAGE:
page_counter_reset_watermark(counter);
break;
case RES_FAILCNT:
counter->failcnt = 0;
break;
default:
BUG();
}
return nbytes;
}
static u64 mem_cgroup_move_charge_read(struct cgroup_subsys_state *css,
struct cftype *cft)
{
return mem_cgroup_from_css(css)->move_charge_at_immigrate;
}
#ifdef CONFIG_MMU
static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
struct cftype *cft, u64 val)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
pr_warn_once("Cgroup memory moving (move_charge_at_immigrate) is deprecated. "
"Please report your usecase to [email protected] if you "
"depend on this functionality.\n");
if (val & ~MOVE_MASK)
return -EINVAL;
/*
* No kind of locking is needed in here, because ->can_attach() will
* check this value once in the beginning of the process, and then carry
* on with stale data. This means that changes to this value will only
* affect task migrations starting after the change.
*/
memcg->move_charge_at_immigrate = val;
return 0;
}
#else
static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
struct cftype *cft, u64 val)
{
return -ENOSYS;
}
#endif
#ifdef CONFIG_NUMA
#define LRU_ALL_FILE (BIT(LRU_INACTIVE_FILE) | BIT(LRU_ACTIVE_FILE))
#define LRU_ALL_ANON (BIT(LRU_INACTIVE_ANON) | BIT(LRU_ACTIVE_ANON))
#define LRU_ALL ((1 << NR_LRU_LISTS) - 1)
static unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
int nid, unsigned int lru_mask, bool tree)
{
struct lruvec *lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(nid));
unsigned long nr = 0;
enum lru_list lru;
VM_BUG_ON((unsigned)nid >= nr_node_ids);
for_each_lru(lru) {
if (!(BIT(lru) & lru_mask))
continue;
if (tree)
nr += lruvec_page_state(lruvec, NR_LRU_BASE + lru);
else
nr += lruvec_page_state_local(lruvec, NR_LRU_BASE + lru);
}
return nr;
}
static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg,
unsigned int lru_mask,
bool tree)
{
unsigned long nr = 0;
enum lru_list lru;
for_each_lru(lru) {
if (!(BIT(lru) & lru_mask))
continue;
if (tree)
nr += memcg_page_state(memcg, NR_LRU_BASE + lru);
else
nr += memcg_page_state_local(memcg, NR_LRU_BASE + lru);
}
return nr;
}
static int memcg_numa_stat_show(struct seq_file *m, void *v)
{
struct numa_stat {
const char *name;
unsigned int lru_mask;
};
static const struct numa_stat stats[] = {
{ "total", LRU_ALL },
{ "file", LRU_ALL_FILE },
{ "anon", LRU_ALL_ANON },
{ "unevictable", BIT(LRU_UNEVICTABLE) },
};
const struct numa_stat *stat;
int nid;
struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
mem_cgroup_flush_stats();
for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
seq_printf(m, "%s=%lu", stat->name,
mem_cgroup_nr_lru_pages(memcg, stat->lru_mask,
false));
for_each_node_state(nid, N_MEMORY)
seq_printf(m, " N%d=%lu", nid,
mem_cgroup_node_nr_lru_pages(memcg, nid,
stat->lru_mask, false));
seq_putc(m, '\n');
}
for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
seq_printf(m, "hierarchical_%s=%lu", stat->name,
mem_cgroup_nr_lru_pages(memcg, stat->lru_mask,
true));
for_each_node_state(nid, N_MEMORY)
seq_printf(m, " N%d=%lu", nid,
mem_cgroup_node_nr_lru_pages(memcg, nid,
stat->lru_mask, true));
seq_putc(m, '\n');
}
return 0;
}
#endif /* CONFIG_NUMA */
static const unsigned int memcg1_stats[] = {
NR_FILE_PAGES,
NR_ANON_MAPPED,
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
NR_ANON_THPS,
#endif
NR_SHMEM,
NR_FILE_MAPPED,
NR_FILE_DIRTY,
NR_WRITEBACK,
WORKINGSET_REFAULT_ANON,
WORKINGSET_REFAULT_FILE,
MEMCG_SWAP,
};
static const char *const memcg1_stat_names[] = {
"cache",
"rss",
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
"rss_huge",
#endif
"shmem",
"mapped_file",
"dirty",
"writeback",
"workingset_refault_anon",
"workingset_refault_file",
"swap",
};
/* Universal VM events cgroup1 shows, original sort order */
static const unsigned int memcg1_events[] = {
PGPGIN,
PGPGOUT,
PGFAULT,
PGMAJFAULT,
};
static void memcg1_stat_format(struct mem_cgroup *memcg, struct seq_buf *s)
{
unsigned long memory, memsw;
struct mem_cgroup *mi;
unsigned int i;
BUILD_BUG_ON(ARRAY_SIZE(memcg1_stat_names) != ARRAY_SIZE(memcg1_stats));
mem_cgroup_flush_stats();
for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) {
unsigned long nr;
if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account())
continue;
nr = memcg_page_state_local(memcg, memcg1_stats[i]);
seq_buf_printf(s, "%s %lu\n", memcg1_stat_names[i],
nr * memcg_page_state_unit(memcg1_stats[i]));
}
for (i = 0; i < ARRAY_SIZE(memcg1_events); i++)
seq_buf_printf(s, "%s %lu\n", vm_event_name(memcg1_events[i]),
memcg_events_local(memcg, memcg1_events[i]));
for (i = 0; i < NR_LRU_LISTS; i++)
seq_buf_printf(s, "%s %lu\n", lru_list_name(i),
memcg_page_state_local(memcg, NR_LRU_BASE + i) *
PAGE_SIZE);
/* Hierarchical information */
memory = memsw = PAGE_COUNTER_MAX;
for (mi = memcg; mi; mi = parent_mem_cgroup(mi)) {
memory = min(memory, READ_ONCE(mi->memory.max));
memsw = min(memsw, READ_ONCE(mi->memsw.max));
}
seq_buf_printf(s, "hierarchical_memory_limit %llu\n",
(u64)memory * PAGE_SIZE);
if (do_memsw_account())
seq_buf_printf(s, "hierarchical_memsw_limit %llu\n",
(u64)memsw * PAGE_SIZE);
for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) {
unsigned long nr;
if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account())
continue;
nr = memcg_page_state(memcg, memcg1_stats[i]);
seq_buf_printf(s, "total_%s %llu\n", memcg1_stat_names[i],
(u64)nr * memcg_page_state_unit(memcg1_stats[i]));
}
for (i = 0; i < ARRAY_SIZE(memcg1_events); i++)
seq_buf_printf(s, "total_%s %llu\n",
vm_event_name(memcg1_events[i]),
(u64)memcg_events(memcg, memcg1_events[i]));
for (i = 0; i < NR_LRU_LISTS; i++)
seq_buf_printf(s, "total_%s %llu\n", lru_list_name(i),
(u64)memcg_page_state(memcg, NR_LRU_BASE + i) *
PAGE_SIZE);
#ifdef CONFIG_DEBUG_VM
{
pg_data_t *pgdat;
struct mem_cgroup_per_node *mz;
unsigned long anon_cost = 0;
unsigned long file_cost = 0;
for_each_online_pgdat(pgdat) {
mz = memcg->nodeinfo[pgdat->node_id];
anon_cost += mz->lruvec.anon_cost;
file_cost += mz->lruvec.file_cost;
}
seq_buf_printf(s, "anon_cost %lu\n", anon_cost);
seq_buf_printf(s, "file_cost %lu\n", file_cost);
}
#endif
}
static u64 mem_cgroup_swappiness_read(struct cgroup_subsys_state *css,
struct cftype *cft)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
return mem_cgroup_swappiness(memcg);
}
static int mem_cgroup_swappiness_write(struct cgroup_subsys_state *css,
struct cftype *cft, u64 val)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
if (val > 200)
return -EINVAL;
if (!mem_cgroup_is_root(memcg))
WRITE_ONCE(memcg->swappiness, val);
else
WRITE_ONCE(vm_swappiness, val);
return 0;
}
static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
{
struct mem_cgroup_threshold_ary *t;
unsigned long usage;
int i;
rcu_read_lock();
if (!swap)
t = rcu_dereference(memcg->thresholds.primary);
else
t = rcu_dereference(memcg->memsw_thresholds.primary);
if (!t)
goto unlock;
usage = mem_cgroup_usage(memcg, swap);
/*
* current_threshold points to threshold just below or equal to usage.
* If it's not true, a threshold was crossed after last
* call of __mem_cgroup_threshold().
*/
i = t->current_threshold;
/*
* Iterate backward over array of thresholds starting from
* current_threshold and check if a threshold is crossed.
* If none of thresholds below usage is crossed, we read
* only one element of the array here.
*/
for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
eventfd_signal(t->entries[i].eventfd, 1);
/* i = current_threshold + 1 */
i++;
/*
* Iterate forward over array of thresholds starting from
* current_threshold+1 and check if a threshold is crossed.
* If none of thresholds above usage is crossed, we read
* only one element of the array here.
*/
for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
eventfd_signal(t->entries[i].eventfd, 1);
/* Update current_threshold */
t->current_threshold = i - 1;
unlock:
rcu_read_unlock();
}
static void mem_cgroup_threshold(struct mem_cgroup *memcg)
{
while (memcg) {
__mem_cgroup_threshold(memcg, false);
if (do_memsw_account())
__mem_cgroup_threshold(memcg, true);
memcg = parent_mem_cgroup(memcg);
}
}
static int compare_thresholds(const void *a, const void *b)
{
const struct mem_cgroup_threshold *_a = a;
const struct mem_cgroup_threshold *_b = b;
if (_a->threshold > _b->threshold)
return 1;
if (_a->threshold < _b->threshold)
return -1;
return 0;
}
static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
{
struct mem_cgroup_eventfd_list *ev;
spin_lock(&memcg_oom_lock);
list_for_each_entry(ev, &memcg->oom_notify, list)
eventfd_signal(ev->eventfd, 1);
spin_unlock(&memcg_oom_lock);
return 0;
}
static void mem_cgroup_oom_notify(struct mem_cgroup *memcg)
{
struct mem_cgroup *iter;
for_each_mem_cgroup_tree(iter, memcg)
mem_cgroup_oom_notify_cb(iter);
}
static int __mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
struct eventfd_ctx *eventfd, const char *args, enum res_type type)
{
struct mem_cgroup_thresholds *thresholds;
struct mem_cgroup_threshold_ary *new;
unsigned long threshold;
unsigned long usage;
int i, size, ret;
ret = page_counter_memparse(args, "-1", &threshold);
if (ret)
return ret;
mutex_lock(&memcg->thresholds_lock);
if (type == _MEM) {
thresholds = &memcg->thresholds;
usage = mem_cgroup_usage(memcg, false);
} else if (type == _MEMSWAP) {
thresholds = &memcg->memsw_thresholds;
usage = mem_cgroup_usage(memcg, true);
} else
BUG();
/* Check if a threshold crossed before adding a new one */
if (thresholds->primary)
__mem_cgroup_threshold(memcg, type == _MEMSWAP);
size = thresholds->primary ? thresholds->primary->size + 1 : 1;
/* Allocate memory for new array of thresholds */
new = kmalloc(struct_size(new, entries, size), GFP_KERNEL);
if (!new) {
ret = -ENOMEM;
goto unlock;
}
new->size = size;
/* Copy thresholds (if any) to new array */
if (thresholds->primary)
memcpy(new->entries, thresholds->primary->entries,
flex_array_size(new, entries, size - 1));
/* Add new threshold */
new->entries[size - 1].eventfd = eventfd;
new->entries[size - 1].threshold = threshold;
/* Sort thresholds. Registering of new threshold isn't time-critical */
sort(new->entries, size, sizeof(*new->entries),
compare_thresholds, NULL);
/* Find current threshold */
new->current_threshold = -1;
for (i = 0; i < size; i++) {
if (new->entries[i].threshold <= usage) {
/*
* new->current_threshold will not be used until
* rcu_assign_pointer(), so it's safe to increment
* it here.
*/
++new->current_threshold;
} else
break;
}
/* Free old spare buffer and save old primary buffer as spare */
kfree(thresholds->spare);
thresholds->spare = thresholds->primary;
rcu_assign_pointer(thresholds->primary, new);
/* To be sure that nobody uses thresholds */
synchronize_rcu();
unlock:
mutex_unlock(&memcg->thresholds_lock);
return ret;
}
static int mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
struct eventfd_ctx *eventfd, const char *args)
{
return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEM);
}
static int memsw_cgroup_usage_register_event(struct mem_cgroup *memcg,
struct eventfd_ctx *eventfd, const char *args)
{
return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEMSWAP);
}
static void __mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
struct eventfd_ctx *eventfd, enum res_type type)
{
struct mem_cgroup_thresholds *thresholds;
struct mem_cgroup_threshold_ary *new;
unsigned long usage;
int i, j, size, entries;
mutex_lock(&memcg->thresholds_lock);
if (type == _MEM) {
thresholds = &memcg->thresholds;
usage = mem_cgroup_usage(memcg, false);
} else if (type == _MEMSWAP) {
thresholds = &memcg->memsw_thresholds;
usage = mem_cgroup_usage(memcg, true);
} else
BUG();
if (!thresholds->primary)
goto unlock;
/* Check if a threshold crossed before removing */
__mem_cgroup_threshold(memcg, type == _MEMSWAP);
/* Calculate new number of threshold */
size = entries = 0;
for (i = 0; i < thresholds->primary->size; i++) {
if (thresholds->primary->entries[i].eventfd != eventfd)
size++;
else
entries++;
}
new = thresholds->spare;
/* If no items related to eventfd have been cleared, nothing to do */
if (!entries)
goto unlock;
/* Set thresholds array to NULL if we don't have thresholds */
if (!size) {
kfree(new);
new = NULL;
goto swap_buffers;
}
new->size = size;
/* Copy thresholds and find current threshold */
new->current_threshold = -1;
for (i = 0, j = 0; i < thresholds->primary->size; i++) {
if (thresholds->primary->entries[i].eventfd == eventfd)
continue;
new->entries[j] = thresholds->primary->entries[i];
if (new->entries[j].threshold <= usage) {
/*
* new->current_threshold will not be used
* until rcu_assign_pointer(), so it's safe to increment
* it here.
*/
++new->current_threshold;
}
j++;
}
swap_buffers:
/* Swap primary and spare array */
thresholds->spare = thresholds->primary;
rcu_assign_pointer(thresholds->primary, new);
/* To be sure that nobody uses thresholds */
synchronize_rcu();
/* If all events are unregistered, free the spare array */
if (!new) {
kfree(thresholds->spare);
thresholds->spare = NULL;
}
unlock:
mutex_unlock(&memcg->thresholds_lock);
}
static void mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
struct eventfd_ctx *eventfd)
{
return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEM);
}
static void memsw_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
struct eventfd_ctx *eventfd)
{
return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEMSWAP);
}
static int mem_cgroup_oom_register_event(struct mem_cgroup *memcg,
struct eventfd_ctx *eventfd, const char *args)
{
struct mem_cgroup_eventfd_list *event;
event = kmalloc(sizeof(*event), GFP_KERNEL);
if (!event)
return -ENOMEM;
spin_lock(&memcg_oom_lock);
event->eventfd = eventfd;
list_add(&event->list, &memcg->oom_notify);
/* already in OOM ? */
if (memcg->under_oom)
eventfd_signal(eventfd, 1);
spin_unlock(&memcg_oom_lock);
return 0;
}
static void mem_cgroup_oom_unregister_event(struct mem_cgroup *memcg,
struct eventfd_ctx *eventfd)
{
struct mem_cgroup_eventfd_list *ev, *tmp;
spin_lock(&memcg_oom_lock);
list_for_each_entry_safe(ev, tmp, &memcg->oom_notify, list) {
if (ev->eventfd == eventfd) {
list_del(&ev->list);
kfree(ev);
}
}
spin_unlock(&memcg_oom_lock);
}
static int mem_cgroup_oom_control_read(struct seq_file *sf, void *v)
{
struct mem_cgroup *memcg = mem_cgroup_from_seq(sf);
seq_printf(sf, "oom_kill_disable %d\n", READ_ONCE(memcg->oom_kill_disable));
seq_printf(sf, "under_oom %d\n", (bool)memcg->under_oom);
seq_printf(sf, "oom_kill %lu\n",
atomic_long_read(&memcg->memory_events[MEMCG_OOM_KILL]));
return 0;
}
static int mem_cgroup_oom_control_write(struct cgroup_subsys_state *css,
struct cftype *cft, u64 val)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
/* cannot set to root cgroup and only 0 and 1 are allowed */
if (mem_cgroup_is_root(memcg) || !((val == 0) || (val == 1)))
return -EINVAL;
WRITE_ONCE(memcg->oom_kill_disable, val);
if (!val)
memcg_oom_recover(memcg);
return 0;
}
#ifdef CONFIG_CGROUP_WRITEBACK
#include <trace/events/writeback.h>
static int memcg_wb_domain_init(struct mem_cgroup *memcg, gfp_t gfp)
{
return wb_domain_init(&memcg->cgwb_domain, gfp);
}
static void memcg_wb_domain_exit(struct mem_cgroup *memcg)
{
wb_domain_exit(&memcg->cgwb_domain);
}
static void memcg_wb_domain_size_changed(struct mem_cgroup *memcg)
{
wb_domain_size_changed(&memcg->cgwb_domain);
}
struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
if (!memcg->css.parent)
return NULL;
return &memcg->cgwb_domain;
}
/**
* mem_cgroup_wb_stats - retrieve writeback related stats from its memcg
* @wb: bdi_writeback in question
* @pfilepages: out parameter for number of file pages
* @pheadroom: out parameter for number of allocatable pages according to memcg
* @pdirty: out parameter for number of dirty pages
* @pwriteback: out parameter for number of pages under writeback
*
* Determine the numbers of file, headroom, dirty, and writeback pages in
* @wb's memcg. File, dirty and writeback are self-explanatory. Headroom
* is a bit more involved.
*
* A memcg's headroom is "min(max, high) - used". In the hierarchy, the
* headroom is calculated as the lowest headroom of itself and the
* ancestors. Note that this doesn't consider the actual amount of
* available memory in the system. The caller should further cap
* *@pheadroom accordingly.
*/
void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pfilepages,
unsigned long *pheadroom, unsigned long *pdirty,
unsigned long *pwriteback)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
struct mem_cgroup *parent;
mem_cgroup_flush_stats();
*pdirty = memcg_page_state(memcg, NR_FILE_DIRTY);
*pwriteback = memcg_page_state(memcg, NR_WRITEBACK);
*pfilepages = memcg_page_state(memcg, NR_INACTIVE_FILE) +
memcg_page_state(memcg, NR_ACTIVE_FILE);
*pheadroom = PAGE_COUNTER_MAX;
while ((parent = parent_mem_cgroup(memcg))) {
unsigned long ceiling = min(READ_ONCE(memcg->memory.max),
READ_ONCE(memcg->memory.high));
unsigned long used = page_counter_read(&memcg->memory);
*pheadroom = min(*pheadroom, ceiling - min(ceiling, used));
memcg = parent;
}
}
/*
* Foreign dirty flushing
*
* There's an inherent mismatch between memcg and writeback. The former
* tracks ownership per-page while the latter per-inode. This was a
* deliberate design decision because honoring per-page ownership in the
* writeback path is complicated, may lead to higher CPU and IO overheads
* and deemed unnecessary given that write-sharing an inode across
* different cgroups isn't a common use-case.
*
* Combined with inode majority-writer ownership switching, this works well
* enough in most cases but there are some pathological cases. For
* example, let's say there are two cgroups A and B which keep writing to
* different but confined parts of the same inode. B owns the inode and
* A's memory is limited far below B's. A's dirty ratio can rise enough to
* trigger balance_dirty_pages() sleeps but B's can be low enough to avoid
* triggering background writeback. A will be slowed down without a way to
* make writeback of the dirty pages happen.
*
* Conditions like the above can lead to a cgroup getting repeatedly and
* severely throttled after making some progress after each
* dirty_expire_interval while the underlying IO device is almost
* completely idle.
*
* Solving this problem completely requires matching the ownership tracking
* granularities between memcg and writeback in either direction. However,
* the more egregious behaviors can be avoided by simply remembering the
* most recent foreign dirtying events and initiating remote flushes on
* them when local writeback isn't enough to keep the memory clean enough.
*
* The following two functions implement such mechanism. When a foreign
* page - a page whose memcg and writeback ownerships don't match - is
* dirtied, mem_cgroup_track_foreign_dirty() records the inode owning
* bdi_writeback on the page owning memcg. When balance_dirty_pages()
* decides that the memcg needs to sleep due to high dirty ratio, it calls
* mem_cgroup_flush_foreign() which queues writeback on the recorded
* foreign bdi_writebacks which haven't expired. Both the numbers of
* recorded bdi_writebacks and concurrent in-flight foreign writebacks are
* limited to MEMCG_CGWB_FRN_CNT.
*
* The mechanism only remembers IDs and doesn't hold any object references.
* As being wrong occasionally doesn't matter, updates and accesses to the
* records are lockless and racy.
*/
void mem_cgroup_track_foreign_dirty_slowpath(struct folio *folio,
struct bdi_writeback *wb)
{
struct mem_cgroup *memcg = folio_memcg(folio);
struct memcg_cgwb_frn *frn;
u64 now = get_jiffies_64();
u64 oldest_at = now;
int oldest = -1;
int i;
trace_track_foreign_dirty(folio, wb);
/*
* Pick the slot to use. If there is already a slot for @wb, keep
* using it. If not replace the oldest one which isn't being
* written out.
*/
for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++) {
frn = &memcg->cgwb_frn[i];
if (frn->bdi_id == wb->bdi->id &&
frn->memcg_id == wb->memcg_css->id)
break;
if (time_before64(frn->at, oldest_at) &&
atomic_read(&frn->done.cnt) == 1) {
oldest = i;
oldest_at = frn->at;
}
}
if (i < MEMCG_CGWB_FRN_CNT) {
/*
* Re-using an existing one. Update timestamp lazily to
* avoid making the cacheline hot. We want them to be
* reasonably up-to-date and significantly shorter than
* dirty_expire_interval as that's what expires the record.
* Use the shorter of 1s and dirty_expire_interval / 8.
*/
unsigned long update_intv =
min_t(unsigned long, HZ,
msecs_to_jiffies(dirty_expire_interval * 10) / 8);
if (time_before64(frn->at, now - update_intv))
frn->at = now;
} else if (oldest >= 0) {
/* replace the oldest free one */
frn = &memcg->cgwb_frn[oldest];
frn->bdi_id = wb->bdi->id;
frn->memcg_id = wb->memcg_css->id;
frn->at = now;
}
}
/* issue foreign writeback flushes for recorded foreign dirtying events */
void mem_cgroup_flush_foreign(struct bdi_writeback *wb)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
unsigned long intv = msecs_to_jiffies(dirty_expire_interval * 10);
u64 now = jiffies_64;
int i;
for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++) {
struct memcg_cgwb_frn *frn = &memcg->cgwb_frn[i];
/*
* If the record is older than dirty_expire_interval,
* writeback on it has already started. No need to kick it
* off again. Also, don't start a new one if there's
* already one in flight.
*/
if (time_after64(frn->at, now - intv) &&
atomic_read(&frn->done.cnt) == 1) {
frn->at = 0;
trace_flush_foreign(wb, frn->bdi_id, frn->memcg_id);
cgroup_writeback_by_id(frn->bdi_id, frn->memcg_id,
WB_REASON_FOREIGN_FLUSH,
&frn->done);
}
}
}
#else /* CONFIG_CGROUP_WRITEBACK */
static int memcg_wb_domain_init(struct mem_cgroup *memcg, gfp_t gfp)
{
return 0;
}
static void memcg_wb_domain_exit(struct mem_cgroup *memcg)
{
}
static void memcg_wb_domain_size_changed(struct mem_cgroup *memcg)
{
}
#endif /* CONFIG_CGROUP_WRITEBACK */
/*
* DO NOT USE IN NEW FILES.
*
* "cgroup.event_control" implementation.
*
* This is way over-engineered. It tries to support fully configurable
* events for each user. Such level of flexibility is completely
* unnecessary especially in the light of the planned unified hierarchy.
*
* Please deprecate this and replace with something simpler if at all
* possible.
*/
/*
* Unregister event and free resources.
*
* Gets called from workqueue.
*/
static void memcg_event_remove(struct work_struct *work)
{
struct mem_cgroup_event *event =
container_of(work, struct mem_cgroup_event, remove);
struct mem_cgroup *memcg = event->memcg;
remove_wait_queue(event->wqh, &event->wait);
event->unregister_event(memcg, event->eventfd);
/* Notify userspace the event is going away. */
eventfd_signal(event->eventfd, 1);
eventfd_ctx_put(event->eventfd);
kfree(event);
css_put(&memcg->css);
}
/*
* Gets called on EPOLLHUP on eventfd when user closes it.
*
* Called with wqh->lock held and interrupts disabled.
*/
static int memcg_event_wake(wait_queue_entry_t *wait, unsigned mode,
int sync, void *key)
{
struct mem_cgroup_event *event =
container_of(wait, struct mem_cgroup_event, wait);
struct mem_cgroup *memcg = event->memcg;
__poll_t flags = key_to_poll(key);
if (flags & EPOLLHUP) {
/*
* If the event has been detached at cgroup removal, we
* can simply return knowing the other side will cleanup
* for us.
*
* We can't race against event freeing since the other
* side will require wqh->lock via remove_wait_queue(),
* which we hold.
*/
spin_lock(&memcg->event_list_lock);
if (!list_empty(&event->list)) {
list_del_init(&event->list);
/*
* We are in atomic context, but cgroup_event_remove()
* may sleep, so we have to call it in workqueue.
*/
schedule_work(&event->remove);
}
spin_unlock(&memcg->event_list_lock);
}
return 0;
}
static void memcg_event_ptable_queue_proc(struct file *file,
wait_queue_head_t *wqh, poll_table *pt)
{
struct mem_cgroup_event *event =
container_of(pt, struct mem_cgroup_event, pt);
event->wqh = wqh;
add_wait_queue(wqh, &event->wait);
}
/*
* DO NOT USE IN NEW FILES.
*
* Parse input and register new cgroup event handler.
*
* Input must be in format '<event_fd> <control_fd> <args>'.
* Interpretation of args is defined by control file implementation.
*/
static ssize_t memcg_write_event_control(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off)
{
struct cgroup_subsys_state *css = of_css(of);
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
struct mem_cgroup_event *event;
struct cgroup_subsys_state *cfile_css;
unsigned int efd, cfd;
struct fd efile;
struct fd cfile;
struct dentry *cdentry;
const char *name;
char *endp;
int ret;
if (IS_ENABLED(CONFIG_PREEMPT_RT))
return -EOPNOTSUPP;
buf = strstrip(buf);
efd = simple_strtoul(buf, &endp, 10);
if (*endp != ' ')
return -EINVAL;
buf = endp + 1;
cfd = simple_strtoul(buf, &endp, 10);
if ((*endp != ' ') && (*endp != '\0'))
return -EINVAL;
buf = endp + 1;
event = kzalloc(sizeof(*event), GFP_KERNEL);
if (!event)
return -ENOMEM;
event->memcg = memcg;
INIT_LIST_HEAD(&event->list);
init_poll_funcptr(&event->pt, memcg_event_ptable_queue_proc);
init_waitqueue_func_entry(&event->wait, memcg_event_wake);
INIT_WORK(&event->remove, memcg_event_remove);
efile = fdget(efd);
if (!efile.file) {
ret = -EBADF;
goto out_kfree;
}
event->eventfd = eventfd_ctx_fileget(efile.file);
if (IS_ERR(event->eventfd)) {
ret = PTR_ERR(event->eventfd);
goto out_put_efile;
}
cfile = fdget(cfd);
if (!cfile.file) {
ret = -EBADF;
goto out_put_eventfd;
}
/* the process need read permission on control file */
/* AV: shouldn't we check that it's been opened for read instead? */
ret = file_permission(cfile.file, MAY_READ);
if (ret < 0)
goto out_put_cfile;
/*
* The control file must be a regular cgroup1 file. As a regular cgroup
* file can't be renamed, it's safe to access its name afterwards.
*/
cdentry = cfile.file->f_path.dentry;
if (cdentry->d_sb->s_type != &cgroup_fs_type || !d_is_reg(cdentry)) {
ret = -EINVAL;
goto out_put_cfile;
}
/*
* Determine the event callbacks and set them in @event. This used
* to be done via struct cftype but cgroup core no longer knows
* about these events. The following is crude but the whole thing
* is for compatibility anyway.
*
* DO NOT ADD NEW FILES.
*/
name = cdentry->d_name.name;
if (!strcmp(name, "memory.usage_in_bytes")) {
event->register_event = mem_cgroup_usage_register_event;
event->unregister_event = mem_cgroup_usage_unregister_event;
} else if (!strcmp(name, "memory.oom_control")) {
event->register_event = mem_cgroup_oom_register_event;
event->unregister_event = mem_cgroup_oom_unregister_event;
} else if (!strcmp(name, "memory.pressure_level")) {
event->register_event = vmpressure_register_event;
event->unregister_event = vmpressure_unregister_event;
} else if (!strcmp(name, "memory.memsw.usage_in_bytes")) {
event->register_event = memsw_cgroup_usage_register_event;
event->unregister_event = memsw_cgroup_usage_unregister_event;
} else {
ret = -EINVAL;
goto out_put_cfile;
}
/*
* Verify @cfile should belong to @css. Also, remaining events are
* automatically removed on cgroup destruction but the removal is
* asynchronous, so take an extra ref on @css.
*/
cfile_css = css_tryget_online_from_dir(cdentry->d_parent,
&memory_cgrp_subsys);
ret = -EINVAL;
if (IS_ERR(cfile_css))
goto out_put_cfile;
if (cfile_css != css) {
css_put(cfile_css);
goto out_put_cfile;
}
ret = event->register_event(memcg, event->eventfd, buf);
if (ret)
goto out_put_css;
vfs_poll(efile.file, &event->pt);
spin_lock_irq(&memcg->event_list_lock);
list_add(&event->list, &memcg->event_list);
spin_unlock_irq(&memcg->event_list_lock);
fdput(cfile);
fdput(efile);
return nbytes;
out_put_css:
css_put(css);
out_put_cfile:
fdput(cfile);
out_put_eventfd:
eventfd_ctx_put(event->eventfd);
out_put_efile:
fdput(efile);
out_kfree:
kfree(event);
return ret;
}
#if defined(CONFIG_MEMCG_KMEM) && (defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG))
static int mem_cgroup_slab_show(struct seq_file *m, void *p)
{
/*
* Deprecated.
* Please, take a look at tools/cgroup/memcg_slabinfo.py .
*/
return 0;
}
#endif
static int memory_stat_show(struct seq_file *m, void *v);
static struct cftype mem_cgroup_legacy_files[] = {
{
.name = "usage_in_bytes",
.private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
.read_u64 = mem_cgroup_read_u64,
},
{
.name = "max_usage_in_bytes",
.private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
.write = mem_cgroup_reset,
.read_u64 = mem_cgroup_read_u64,
},
{
.name = "limit_in_bytes",
.private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
.write = mem_cgroup_write,
.read_u64 = mem_cgroup_read_u64,
},
{
.name = "soft_limit_in_bytes",
.private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
.write = mem_cgroup_write,
.read_u64 = mem_cgroup_read_u64,
},
{
.name = "failcnt",
.private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
.write = mem_cgroup_reset,
.read_u64 = mem_cgroup_read_u64,
},
{
.name = "stat",
.seq_show = memory_stat_show,
},
{
.name = "force_empty",
.write = mem_cgroup_force_empty_write,
},
{
.name = "use_hierarchy",
.write_u64 = mem_cgroup_hierarchy_write,
.read_u64 = mem_cgroup_hierarchy_read,
},
{
.name = "cgroup.event_control", /* XXX: for compat */
.write = memcg_write_event_control,
.flags = CFTYPE_NO_PREFIX | CFTYPE_WORLD_WRITABLE,
},
{
.name = "swappiness",
.read_u64 = mem_cgroup_swappiness_read,
.write_u64 = mem_cgroup_swappiness_write,
},
{
.name = "move_charge_at_immigrate",
.read_u64 = mem_cgroup_move_charge_read,
.write_u64 = mem_cgroup_move_charge_write,
},
{
.name = "oom_control",
.seq_show = mem_cgroup_oom_control_read,
.write_u64 = mem_cgroup_oom_control_write,
},
{
.name = "pressure_level",
.seq_show = mem_cgroup_dummy_seq_show,
},
#ifdef CONFIG_NUMA
{
.name = "numa_stat",
.seq_show = memcg_numa_stat_show,
},
#endif
{
.name = "kmem.usage_in_bytes",
.private = MEMFILE_PRIVATE(_KMEM, RES_USAGE),
.read_u64 = mem_cgroup_read_u64,
},
{
.name = "kmem.failcnt",
.private = MEMFILE_PRIVATE(_KMEM, RES_FAILCNT),
.write = mem_cgroup_reset,
.read_u64 = mem_cgroup_read_u64,
},
{
.name = "kmem.max_usage_in_bytes",
.private = MEMFILE_PRIVATE(_KMEM, RES_MAX_USAGE),
.write = mem_cgroup_reset,
.read_u64 = mem_cgroup_read_u64,
},
#if defined(CONFIG_MEMCG_KMEM) && \
(defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG))
{
.name = "kmem.slabinfo",
.seq_show = mem_cgroup_slab_show,
},
#endif
{
.name = "kmem.tcp.limit_in_bytes",
.private = MEMFILE_PRIVATE(_TCP, RES_LIMIT),
.write = mem_cgroup_write,
.read_u64 = mem_cgroup_read_u64,
},
{
.name = "kmem.tcp.usage_in_bytes",
.private = MEMFILE_PRIVATE(_TCP, RES_USAGE),
.read_u64 = mem_cgroup_read_u64,
},
{
.name = "kmem.tcp.failcnt",
.private = MEMFILE_PRIVATE(_TCP, RES_FAILCNT),
.write = mem_cgroup_reset,
.read_u64 = mem_cgroup_read_u64,
},
{
.name = "kmem.tcp.max_usage_in_bytes",
.private = MEMFILE_PRIVATE(_TCP, RES_MAX_USAGE),
.write = mem_cgroup_reset,
.read_u64 = mem_cgroup_read_u64,
},
{ }, /* terminate */
};
/*
* Private memory cgroup IDR
*
* Swap-out records and page cache shadow entries need to store memcg
* references in constrained space, so we maintain an ID space that is
* limited to 16 bit (MEM_CGROUP_ID_MAX), limiting the total number of
* memory-controlled cgroups to 64k.
*
* However, there usually are many references to the offline CSS after
* the cgroup has been destroyed, such as page cache or reclaimable
* slab objects, that don't need to hang on to the ID. We want to keep
* those dead CSS from occupying IDs, or we might quickly exhaust the
* relatively small ID space and prevent the creation of new cgroups
* even when there are much fewer than 64k cgroups - possibly none.
*
* Maintain a private 16-bit ID space for memcg, and allow the ID to
* be freed and recycled when it's no longer needed, which is usually
* when the CSS is offlined.
*
* The only exception to that are records of swapped out tmpfs/shmem
* pages that need to be attributed to live ancestors on swapin. But
* those references are manageable from userspace.
*/
#define MEM_CGROUP_ID_MAX ((1UL << MEM_CGROUP_ID_SHIFT) - 1)
static DEFINE_IDR(mem_cgroup_idr);
static void mem_cgroup_id_remove(struct mem_cgroup *memcg)
{
if (memcg->id.id > 0) {
idr_remove(&mem_cgroup_idr, memcg->id.id);
memcg->id.id = 0;
}
}
static void __maybe_unused mem_cgroup_id_get_many(struct mem_cgroup *memcg,
unsigned int n)
{
refcount_add(n, &memcg->id.ref);
}
static void mem_cgroup_id_put_many(struct mem_cgroup *memcg, unsigned int n)
{
if (refcount_sub_and_test(n, &memcg->id.ref)) {
mem_cgroup_id_remove(memcg);
/* Memcg ID pins CSS */
css_put(&memcg->css);
}
}
static inline void mem_cgroup_id_put(struct mem_cgroup *memcg)
{
mem_cgroup_id_put_many(memcg, 1);
}
/**
* mem_cgroup_from_id - look up a memcg from a memcg id
* @id: the memcg id to look up
*
* Caller must hold rcu_read_lock().
*/
struct mem_cgroup *mem_cgroup_from_id(unsigned short id)
{
WARN_ON_ONCE(!rcu_read_lock_held());
return idr_find(&mem_cgroup_idr, id);
}
#ifdef CONFIG_SHRINKER_DEBUG
struct mem_cgroup *mem_cgroup_get_from_ino(unsigned long ino)
{
struct cgroup *cgrp;
struct cgroup_subsys_state *css;
struct mem_cgroup *memcg;
cgrp = cgroup_get_from_id(ino);
if (IS_ERR(cgrp))
return ERR_CAST(cgrp);
css = cgroup_get_e_css(cgrp, &memory_cgrp_subsys);
if (css)
memcg = container_of(css, struct mem_cgroup, css);
else
memcg = ERR_PTR(-ENOENT);
cgroup_put(cgrp);
return memcg;
}
#endif
static int alloc_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node)
{
struct mem_cgroup_per_node *pn;
pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, node);
if (!pn)
return 1;
pn->lruvec_stats_percpu = alloc_percpu_gfp(struct lruvec_stats_percpu,
GFP_KERNEL_ACCOUNT);
if (!pn->lruvec_stats_percpu) {
kfree(pn);
return 1;
}
lruvec_init(&pn->lruvec);
pn->memcg = memcg;
memcg->nodeinfo[node] = pn;
return 0;
}
static void free_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node)
{
struct mem_cgroup_per_node *pn = memcg->nodeinfo[node];
if (!pn)
return;
free_percpu(pn->lruvec_stats_percpu);
kfree(pn);
}
static void __mem_cgroup_free(struct mem_cgroup *memcg)
{
int node;
for_each_node(node)
free_mem_cgroup_per_node_info(memcg, node);
kfree(memcg->vmstats);
free_percpu(memcg->vmstats_percpu);
kfree(memcg);
}
static void mem_cgroup_free(struct mem_cgroup *memcg)
{
lru_gen_exit_memcg(memcg);
memcg_wb_domain_exit(memcg);
__mem_cgroup_free(memcg);
}
static struct mem_cgroup *mem_cgroup_alloc(void)
{
struct mem_cgroup *memcg;
int node;
int __maybe_unused i;
long error = -ENOMEM;
memcg = kzalloc(struct_size(memcg, nodeinfo, nr_node_ids), GFP_KERNEL);
if (!memcg)
return ERR_PTR(error);
memcg->id.id = idr_alloc(&mem_cgroup_idr, NULL,
1, MEM_CGROUP_ID_MAX + 1, GFP_KERNEL);
if (memcg->id.id < 0) {
error = memcg->id.id;
goto fail;
}
memcg->vmstats = kzalloc(sizeof(struct memcg_vmstats), GFP_KERNEL);
if (!memcg->vmstats)
goto fail;
memcg->vmstats_percpu = alloc_percpu_gfp(struct memcg_vmstats_percpu,
GFP_KERNEL_ACCOUNT);
if (!memcg->vmstats_percpu)
goto fail;
for_each_node(node)
if (alloc_mem_cgroup_per_node_info(memcg, node))
goto fail;
if (memcg_wb_domain_init(memcg, GFP_KERNEL))
goto fail;
INIT_WORK(&memcg->high_work, high_work_func);
INIT_LIST_HEAD(&memcg->oom_notify);
mutex_init(&memcg->thresholds_lock);
spin_lock_init(&memcg->move_lock);
vmpressure_init(&memcg->vmpressure);
INIT_LIST_HEAD(&memcg->event_list);
spin_lock_init(&memcg->event_list_lock);
memcg->socket_pressure = jiffies;
#ifdef CONFIG_MEMCG_KMEM
memcg->kmemcg_id = -1;
INIT_LIST_HEAD(&memcg->objcg_list);
#endif
#ifdef CONFIG_CGROUP_WRITEBACK
INIT_LIST_HEAD(&memcg->cgwb_list);
for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++)
memcg->cgwb_frn[i].done =
__WB_COMPLETION_INIT(&memcg_cgwb_frn_waitq);
#endif
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
spin_lock_init(&memcg->deferred_split_queue.split_queue_lock);
INIT_LIST_HEAD(&memcg->deferred_split_queue.split_queue);
memcg->deferred_split_queue.split_queue_len = 0;
#endif
lru_gen_init_memcg(memcg);
return memcg;
fail:
mem_cgroup_id_remove(memcg);
__mem_cgroup_free(memcg);
return ERR_PTR(error);
}
static struct cgroup_subsys_state * __ref
mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
{
struct mem_cgroup *parent = mem_cgroup_from_css(parent_css);
struct mem_cgroup *memcg, *old_memcg;
old_memcg = set_active_memcg(parent);
memcg = mem_cgroup_alloc();
set_active_memcg(old_memcg);
if (IS_ERR(memcg))
return ERR_CAST(memcg);
page_counter_set_high(&memcg->memory, PAGE_COUNTER_MAX);
WRITE_ONCE(memcg->soft_limit, PAGE_COUNTER_MAX);
#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP)
memcg->zswap_max = PAGE_COUNTER_MAX;
#endif
page_counter_set_high(&memcg->swap, PAGE_COUNTER_MAX);
if (parent) {
WRITE_ONCE(memcg->swappiness, mem_cgroup_swappiness(parent));
WRITE_ONCE(memcg->oom_kill_disable, READ_ONCE(parent->oom_kill_disable));
page_counter_init(&memcg->memory, &parent->memory);
page_counter_init(&memcg->swap, &parent->swap);
page_counter_init(&memcg->kmem, &parent->kmem);
page_counter_init(&memcg->tcpmem, &parent->tcpmem);
} else {
init_memcg_events();
page_counter_init(&memcg->memory, NULL);
page_counter_init(&memcg->swap, NULL);
page_counter_init(&memcg->kmem, NULL);
page_counter_init(&memcg->tcpmem, NULL);
root_mem_cgroup = memcg;
return &memcg->css;
}
if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket)
static_branch_inc(&memcg_sockets_enabled_key);
#if defined(CONFIG_MEMCG_KMEM)
if (!cgroup_memory_nobpf)
static_branch_inc(&memcg_bpf_enabled_key);
#endif
return &memcg->css;
}
static int mem_cgroup_css_online(struct cgroup_subsys_state *css)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
if (memcg_online_kmem(memcg))
goto remove_id;
/*
* A memcg must be visible for expand_shrinker_info()
* by the time the maps are allocated. So, we allocate maps
* here, when for_each_mem_cgroup() can't skip it.
*/
if (alloc_shrinker_info(memcg))
goto offline_kmem;
if (unlikely(mem_cgroup_is_root(memcg)))
queue_delayed_work(system_unbound_wq, &stats_flush_dwork,
FLUSH_TIME);
lru_gen_online_memcg(memcg);
/* Online state pins memcg ID, memcg ID pins CSS */
refcount_set(&memcg->id.ref, 1);
css_get(css);
/*
* Ensure mem_cgroup_from_id() works once we're fully online.
*
* We could do this earlier and require callers to filter with
* css_tryget_online(). But right now there are no users that
* need earlier access, and the workingset code relies on the
* cgroup tree linkage (mem_cgroup_get_nr_swap_pages()). So
* publish it here at the end of onlining. This matches the
* regular ID destruction during offlining.
*/
idr_replace(&mem_cgroup_idr, memcg, memcg->id.id);
return 0;
offline_kmem:
memcg_offline_kmem(memcg);
remove_id:
mem_cgroup_id_remove(memcg);
return -ENOMEM;
}
static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
struct mem_cgroup_event *event, *tmp;
/*
* Unregister events and notify userspace.
* Notify userspace about cgroup removing only after rmdir of cgroup
* directory to avoid race between userspace and kernelspace.
*/
spin_lock_irq(&memcg->event_list_lock);
list_for_each_entry_safe(event, tmp, &memcg->event_list, list) {
list_del_init(&event->list);
schedule_work(&event->remove);
}
spin_unlock_irq(&memcg->event_list_lock);
page_counter_set_min(&memcg->memory, 0);
page_counter_set_low(&memcg->memory, 0);
memcg_offline_kmem(memcg);
reparent_shrinker_deferred(memcg);
wb_memcg_offline(memcg);
lru_gen_offline_memcg(memcg);
drain_all_stock(memcg);
mem_cgroup_id_put(memcg);
}
static void mem_cgroup_css_released(struct cgroup_subsys_state *css)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
invalidate_reclaim_iterators(memcg);
lru_gen_release_memcg(memcg);
}
static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
int __maybe_unused i;
#ifdef CONFIG_CGROUP_WRITEBACK
for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++)
wb_wait_for_completion(&memcg->cgwb_frn[i].done);
#endif
if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket)
static_branch_dec(&memcg_sockets_enabled_key);
if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && memcg->tcpmem_active)
static_branch_dec(&memcg_sockets_enabled_key);
#if defined(CONFIG_MEMCG_KMEM)
if (!cgroup_memory_nobpf)
static_branch_dec(&memcg_bpf_enabled_key);
#endif
vmpressure_cleanup(&memcg->vmpressure);
cancel_work_sync(&memcg->high_work);
mem_cgroup_remove_from_trees(memcg);
free_shrinker_info(memcg);
mem_cgroup_free(memcg);
}
/**
* mem_cgroup_css_reset - reset the states of a mem_cgroup
* @css: the target css
*
* Reset the states of the mem_cgroup associated with @css. This is
* invoked when the userland requests disabling on the default hierarchy
* but the memcg is pinned through dependency. The memcg should stop
* applying policies and should revert to the vanilla state as it may be
* made visible again.
*
* The current implementation only resets the essential configurations.
* This needs to be expanded to cover all the visible parts.
*/
static void mem_cgroup_css_reset(struct cgroup_subsys_state *css)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
page_counter_set_max(&memcg->memory, PAGE_COUNTER_MAX);
page_counter_set_max(&memcg->swap, PAGE_COUNTER_MAX);
page_counter_set_max(&memcg->kmem, PAGE_COUNTER_MAX);
page_counter_set_max(&memcg->tcpmem, PAGE_COUNTER_MAX);
page_counter_set_min(&memcg->memory, 0);
page_counter_set_low(&memcg->memory, 0);
page_counter_set_high(&memcg->memory, PAGE_COUNTER_MAX);
WRITE_ONCE(memcg->soft_limit, PAGE_COUNTER_MAX);
page_counter_set_high(&memcg->swap, PAGE_COUNTER_MAX);
memcg_wb_domain_size_changed(memcg);
}
static void mem_cgroup_css_rstat_flush(struct cgroup_subsys_state *css, int cpu)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
struct mem_cgroup *parent = parent_mem_cgroup(memcg);
struct memcg_vmstats_percpu *statc;
long delta, delta_cpu, v;
int i, nid;
statc = per_cpu_ptr(memcg->vmstats_percpu, cpu);
for (i = 0; i < MEMCG_NR_STAT; i++) {
/*
* Collect the aggregated propagation counts of groups
* below us. We're in a per-cpu loop here and this is
* a global counter, so the first cycle will get them.
*/
delta = memcg->vmstats->state_pending[i];
if (delta)
memcg->vmstats->state_pending[i] = 0;
/* Add CPU changes on this level since the last flush */
delta_cpu = 0;
v = READ_ONCE(statc->state[i]);
if (v != statc->state_prev[i]) {
delta_cpu = v - statc->state_prev[i];
delta += delta_cpu;
statc->state_prev[i] = v;
}
/* Aggregate counts on this level and propagate upwards */
if (delta_cpu)
memcg->vmstats->state_local[i] += delta_cpu;
if (delta) {
memcg->vmstats->state[i] += delta;
if (parent)
parent->vmstats->state_pending[i] += delta;
}
}
for (i = 0; i < NR_MEMCG_EVENTS; i++) {
delta = memcg->vmstats->events_pending[i];
if (delta)
memcg->vmstats->events_pending[i] = 0;
delta_cpu = 0;
v = READ_ONCE(statc->events[i]);
if (v != statc->events_prev[i]) {
delta_cpu = v - statc->events_prev[i];
delta += delta_cpu;
statc->events_prev[i] = v;
}
if (delta_cpu)
memcg->vmstats->events_local[i] += delta_cpu;
if (delta) {
memcg->vmstats->events[i] += delta;
if (parent)
parent->vmstats->events_pending[i] += delta;
}
}
for_each_node_state(nid, N_MEMORY) {
struct mem_cgroup_per_node *pn = memcg->nodeinfo[nid];
struct mem_cgroup_per_node *ppn = NULL;
struct lruvec_stats_percpu *lstatc;
if (parent)
ppn = parent->nodeinfo[nid];
lstatc = per_cpu_ptr(pn->lruvec_stats_percpu, cpu);
for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
delta = pn->lruvec_stats.state_pending[i];
if (delta)
pn->lruvec_stats.state_pending[i] = 0;
delta_cpu = 0;
v = READ_ONCE(lstatc->state[i]);
if (v != lstatc->state_prev[i]) {
delta_cpu = v - lstatc->state_prev[i];
delta += delta_cpu;
lstatc->state_prev[i] = v;
}
if (delta_cpu)
pn->lruvec_stats.state_local[i] += delta_cpu;
if (delta) {
pn->lruvec_stats.state[i] += delta;
if (ppn)
ppn->lruvec_stats.state_pending[i] += delta;
}
}
}
}
#ifdef CONFIG_MMU
/* Handlers for move charge at task migration. */
static int mem_cgroup_do_precharge(unsigned long count)
{
int ret;
/* Try a single bulk charge without reclaim first, kswapd may wake */
ret = try_charge(mc.to, GFP_KERNEL & ~__GFP_DIRECT_RECLAIM, count);
if (!ret) {
mc.precharge += count;
return ret;
}
/* Try charges one by one with reclaim, but do not retry */
while (count--) {
ret = try_charge(mc.to, GFP_KERNEL | __GFP_NORETRY, 1);
if (ret)
return ret;
mc.precharge++;
cond_resched();
}
return 0;
}
union mc_target {
struct page *page;
swp_entry_t ent;
};
enum mc_target_type {
MC_TARGET_NONE = 0,
MC_TARGET_PAGE,
MC_TARGET_SWAP,
MC_TARGET_DEVICE,
};
static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
unsigned long addr, pte_t ptent)
{
struct page *page = vm_normal_page(vma, addr, ptent);
if (!page)
return NULL;
if (PageAnon(page)) {
if (!(mc.flags & MOVE_ANON))
return NULL;
} else {
if (!(mc.flags & MOVE_FILE))
return NULL;
}
get_page(page);
return page;
}
#if defined(CONFIG_SWAP) || defined(CONFIG_DEVICE_PRIVATE)
static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
pte_t ptent, swp_entry_t *entry)
{
struct page *page = NULL;
swp_entry_t ent = pte_to_swp_entry(ptent);
if (!(mc.flags & MOVE_ANON))
return NULL;
/*
* Handle device private pages that are not accessible by the CPU, but
* stored as special swap entries in the page table.
*/
if (is_device_private_entry(ent)) {
page = pfn_swap_entry_to_page(ent);
if (!get_page_unless_zero(page))
return NULL;
return page;
}
if (non_swap_entry(ent))
return NULL;
/*
* Because swap_cache_get_folio() updates some statistics counter,
* we call find_get_page() with swapper_space directly.
*/
page = find_get_page(swap_address_space(ent), swp_offset(ent));
entry->val = ent.val;
return page;
}
#else
static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
pte_t ptent, swp_entry_t *entry)
{
return NULL;
}
#endif
static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
unsigned long addr, pte_t ptent)
{
unsigned long index;
struct folio *folio;
if (!vma->vm_file) /* anonymous vma */
return NULL;
if (!(mc.flags & MOVE_FILE))
return NULL;
/* folio is moved even if it's not RSS of this task(page-faulted). */
/* shmem/tmpfs may report page out on swap: account for that too. */
index = linear_page_index(vma, addr);
folio = filemap_get_incore_folio(vma->vm_file->f_mapping, index);
if (IS_ERR(folio))
return NULL;
return folio_file_page(folio, index);
}
/**
* mem_cgroup_move_account - move account of the page
* @page: the page
* @compound: charge the page as compound or small page
* @from: mem_cgroup which the page is moved from.
* @to: mem_cgroup which the page is moved to. @from != @to.
*
* The page must be locked and not on the LRU.
*
* This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
* from old cgroup.
*/
static int mem_cgroup_move_account(struct page *page,
bool compound,
struct mem_cgroup *from,
struct mem_cgroup *to)
{
struct folio *folio = page_folio(page);
struct lruvec *from_vec, *to_vec;
struct pglist_data *pgdat;
unsigned int nr_pages = compound ? folio_nr_pages(folio) : 1;
int nid, ret;
VM_BUG_ON(from == to);
VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);
VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
VM_BUG_ON(compound && !folio_test_large(folio));
ret = -EINVAL;
if (folio_memcg(folio) != from)
goto out;
pgdat = folio_pgdat(folio);
from_vec = mem_cgroup_lruvec(from, pgdat);
to_vec = mem_cgroup_lruvec(to, pgdat);
folio_memcg_lock(folio);
if (folio_test_anon(folio)) {
if (folio_mapped(folio)) {
__mod_lruvec_state(from_vec, NR_ANON_MAPPED, -nr_pages);
__mod_lruvec_state(to_vec, NR_ANON_MAPPED, nr_pages);
if (folio_test_pmd_mappable(folio)) {
__mod_lruvec_state(from_vec, NR_ANON_THPS,
-nr_pages);
__mod_lruvec_state(to_vec, NR_ANON_THPS,
nr_pages);
}
}
} else {
__mod_lruvec_state(from_vec, NR_FILE_PAGES, -nr_pages);
__mod_lruvec_state(to_vec, NR_FILE_PAGES, nr_pages);
if (folio_test_swapbacked(folio)) {
__mod_lruvec_state(from_vec, NR_SHMEM, -nr_pages);
__mod_lruvec_state(to_vec, NR_SHMEM, nr_pages);
}
if (folio_mapped(folio)) {
__mod_lruvec_state(from_vec, NR_FILE_MAPPED, -nr_pages);
__mod_lruvec_state(to_vec, NR_FILE_MAPPED, nr_pages);
}
if (folio_test_dirty(folio)) {
struct address_space *mapping = folio_mapping(folio);
if (mapping_can_writeback(mapping)) {
__mod_lruvec_state(from_vec, NR_FILE_DIRTY,
-nr_pages);
__mod_lruvec_state(to_vec, NR_FILE_DIRTY,
nr_pages);
}
}
}
#ifdef CONFIG_SWAP
if (folio_test_swapcache(folio)) {
__mod_lruvec_state(from_vec, NR_SWAPCACHE, -nr_pages);
__mod_lruvec_state(to_vec, NR_SWAPCACHE, nr_pages);
}
#endif
if (folio_test_writeback(folio)) {
__mod_lruvec_state(from_vec, NR_WRITEBACK, -nr_pages);
__mod_lruvec_state(to_vec, NR_WRITEBACK, nr_pages);
}
/*
* All state has been migrated, let's switch to the new memcg.
*
* It is safe to change page's memcg here because the page
* is referenced, charged, isolated, and locked: we can't race
* with (un)charging, migration, LRU putback, or anything else
* that would rely on a stable page's memory cgroup.
*
* Note that folio_memcg_lock is a memcg lock, not a page lock,
* to save space. As soon as we switch page's memory cgroup to a
* new memcg that isn't locked, the above state can change
* concurrently again. Make sure we're truly done with it.
*/
smp_mb();
css_get(&to->css);
css_put(&from->css);
folio->memcg_data = (unsigned long)to;
__folio_memcg_unlock(from);
ret = 0;
nid = folio_nid(folio);
local_irq_disable();
mem_cgroup_charge_statistics(to, nr_pages);
memcg_check_events(to, nid);
mem_cgroup_charge_statistics(from, -nr_pages);
memcg_check_events(from, nid);
local_irq_enable();
out:
return ret;
}
/**
* get_mctgt_type - get target type of moving charge
* @vma: the vma the pte to be checked belongs
* @addr: the address corresponding to the pte to be checked
* @ptent: the pte to be checked
* @target: the pointer the target page or swap ent will be stored(can be NULL)
*
* Context: Called with pte lock held.
* Return:
* * MC_TARGET_NONE - If the pte is not a target for move charge.
* * MC_TARGET_PAGE - If the page corresponding to this pte is a target for
* move charge. If @target is not NULL, the page is stored in target->page
* with extra refcnt taken (Caller should release it).
* * MC_TARGET_SWAP - If the swap entry corresponding to this pte is a
* target for charge migration. If @target is not NULL, the entry is
* stored in target->ent.
* * MC_TARGET_DEVICE - Like MC_TARGET_PAGE but page is device memory and
* thus not on the lru. For now such page is charged like a regular page
* would be as it is just special memory taking the place of a regular page.
* See Documentations/vm/hmm.txt and include/linux/hmm.h
*/
static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma,
unsigned long addr, pte_t ptent, union mc_target *target)
{
struct page *page = NULL;
enum mc_target_type ret = MC_TARGET_NONE;
swp_entry_t ent = { .val = 0 };
if (pte_present(ptent))
page = mc_handle_present_pte(vma, addr, ptent);
else if (pte_none_mostly(ptent))
/*
* PTE markers should be treated as a none pte here, separated
* from other swap handling below.
*/
page = mc_handle_file_pte(vma, addr, ptent);
else if (is_swap_pte(ptent))
page = mc_handle_swap_pte(vma, ptent, &ent);
if (target && page) {
if (!trylock_page(page)) {
put_page(page);
return ret;
}
/*
* page_mapped() must be stable during the move. This
* pte is locked, so if it's present, the page cannot
* become unmapped. If it isn't, we have only partial
* control over the mapped state: the page lock will
* prevent new faults against pagecache and swapcache,
* so an unmapped page cannot become mapped. However,
* if the page is already mapped elsewhere, it can
* unmap, and there is nothing we can do about it.
* Alas, skip moving the page in this case.
*/
if (!pte_present(ptent) && page_mapped(page)) {
unlock_page(page);
put_page(page);
return ret;
}
}
if (!page && !ent.val)
return ret;
if (page) {
/*
* Do only loose check w/o serialization.
* mem_cgroup_move_account() checks the page is valid or
* not under LRU exclusion.
*/
if (page_memcg(page) == mc.from) {
ret = MC_TARGET_PAGE;
if (is_device_private_page(page) ||
is_device_coherent_page(page))
ret = MC_TARGET_DEVICE;
if (target)
target->page = page;
}
if (!ret || !target) {
if (target)
unlock_page(page);
put_page(page);
}
}
/*
* There is a swap entry and a page doesn't exist or isn't charged.
* But we cannot move a tail-page in a THP.
*/
if (ent.val && !ret && (!page || !PageTransCompound(page)) &&
mem_cgroup_id(mc.from) == lookup_swap_cgroup_id(ent)) {
ret = MC_TARGET_SWAP;
if (target)
target->ent = ent;
}
return ret;
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
/*
* We don't consider PMD mapped swapping or file mapped pages because THP does
* not support them for now.
* Caller should make sure that pmd_trans_huge(pmd) is true.
*/
static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
unsigned long addr, pmd_t pmd, union mc_target *target)
{
struct page *page = NULL;
enum mc_target_type ret = MC_TARGET_NONE;
if (unlikely(is_swap_pmd(pmd))) {
VM_BUG_ON(thp_migration_supported() &&
!is_pmd_migration_entry(pmd));
return ret;
}
page = pmd_page(pmd);
VM_BUG_ON_PAGE(!page || !PageHead(page), page);
if (!(mc.flags & MOVE_ANON))
return ret;
if (page_memcg(page) == mc.from) {
ret = MC_TARGET_PAGE;
if (target) {
get_page(page);
if (!trylock_page(page)) {
put_page(page);
return MC_TARGET_NONE;
}
target->page = page;
}
}
return ret;
}
#else
static inline enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
unsigned long addr, pmd_t pmd, union mc_target *target)
{
return MC_TARGET_NONE;
}
#endif
static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
unsigned long addr, unsigned long end,
struct mm_walk *walk)
{
struct vm_area_struct *vma = walk->vma;
pte_t *pte;
spinlock_t *ptl;
ptl = pmd_trans_huge_lock(pmd, vma);
if (ptl) {
/*
* Note their can not be MC_TARGET_DEVICE for now as we do not
* support transparent huge page with MEMORY_DEVICE_PRIVATE but
* this might change.
*/
if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE)
mc.precharge += HPAGE_PMD_NR;
spin_unlock(ptl);
return 0;
}
pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
if (!pte)
return 0;
for (; addr != end; pte++, addr += PAGE_SIZE)
if (get_mctgt_type(vma, addr, ptep_get(pte), NULL))
mc.precharge++; /* increment precharge temporarily */
pte_unmap_unlock(pte - 1, ptl);
cond_resched();
return 0;
}
static const struct mm_walk_ops precharge_walk_ops = {
.pmd_entry = mem_cgroup_count_precharge_pte_range,
.walk_lock = PGWALK_RDLOCK,
};
static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
{
unsigned long precharge;
mmap_read_lock(mm);
walk_page_range(mm, 0, ULONG_MAX, &precharge_walk_ops, NULL);
mmap_read_unlock(mm);
precharge = mc.precharge;
mc.precharge = 0;
return precharge;
}
static int mem_cgroup_precharge_mc(struct mm_struct *mm)
{
unsigned long precharge = mem_cgroup_count_precharge(mm);
VM_BUG_ON(mc.moving_task);
mc.moving_task = current;
return mem_cgroup_do_precharge(precharge);
}
/* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
static void __mem_cgroup_clear_mc(void)
{
struct mem_cgroup *from = mc.from;
struct mem_cgroup *to = mc.to;
/* we must uncharge all the leftover precharges from mc.to */
if (mc.precharge) {
cancel_charge(mc.to, mc.precharge);
mc.precharge = 0;
}
/*
* we didn't uncharge from mc.from at mem_cgroup_move_account(), so
* we must uncharge here.
*/
if (mc.moved_charge) {
cancel_charge(mc.from, mc.moved_charge);
mc.moved_charge = 0;
}
/* we must fixup refcnts and charges */
if (mc.moved_swap) {
/* uncharge swap account from the old cgroup */
if (!mem_cgroup_is_root(mc.from))
page_counter_uncharge(&mc.from->memsw, mc.moved_swap);
mem_cgroup_id_put_many(mc.from, mc.moved_swap);
/*
* we charged both to->memory and to->memsw, so we
* should uncharge to->memory.
*/
if (!mem_cgroup_is_root(mc.to))
page_counter_uncharge(&mc.to->memory, mc.moved_swap);
mc.moved_swap = 0;
}
memcg_oom_recover(from);
memcg_oom_recover(to);
wake_up_all(&mc.waitq);
}
static void mem_cgroup_clear_mc(void)
{
struct mm_struct *mm = mc.mm;
/*
* we must clear moving_task before waking up waiters at the end of
* task migration.
*/
mc.moving_task = NULL;
__mem_cgroup_clear_mc();
spin_lock(&mc.lock);
mc.from = NULL;
mc.to = NULL;
mc.mm = NULL;
spin_unlock(&mc.lock);
mmput(mm);
}
static int mem_cgroup_can_attach(struct cgroup_taskset *tset)
{
struct cgroup_subsys_state *css;
struct mem_cgroup *memcg = NULL; /* unneeded init to make gcc happy */
struct mem_cgroup *from;
struct task_struct *leader, *p;
struct mm_struct *mm;
unsigned long move_flags;
int ret = 0;
/* charge immigration isn't supported on the default hierarchy */
if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
return 0;
/*
* Multi-process migrations only happen on the default hierarchy
* where charge immigration is not used. Perform charge
* immigration if @tset contains a leader and whine if there are
* multiple.
*/
p = NULL;
cgroup_taskset_for_each_leader(leader, css, tset) {
WARN_ON_ONCE(p);
p = leader;
memcg = mem_cgroup_from_css(css);
}
if (!p)
return 0;
/*
* We are now committed to this value whatever it is. Changes in this
* tunable will only affect upcoming migrations, not the current one.
* So we need to save it, and keep it going.
*/
move_flags = READ_ONCE(memcg->move_charge_at_immigrate);
if (!move_flags)
return 0;
from = mem_cgroup_from_task(p);
VM_BUG_ON(from == memcg);
mm = get_task_mm(p);
if (!mm)
return 0;
/* We move charges only when we move a owner of the mm */
if (mm->owner == p) {
VM_BUG_ON(mc.from);
VM_BUG_ON(mc.to);
VM_BUG_ON(mc.precharge);
VM_BUG_ON(mc.moved_charge);
VM_BUG_ON(mc.moved_swap);
spin_lock(&mc.lock);
mc.mm = mm;
mc.from = from;
mc.to = memcg;
mc.flags = move_flags;
spin_unlock(&mc.lock);
/* We set mc.moving_task later */
ret = mem_cgroup_precharge_mc(mm);
if (ret)
mem_cgroup_clear_mc();
} else {
mmput(mm);
}
return ret;
}
static void mem_cgroup_cancel_attach(struct cgroup_taskset *tset)
{
if (mc.to)
mem_cgroup_clear_mc();
}
static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
unsigned long addr, unsigned long end,
struct mm_walk *walk)
{
int ret = 0;
struct vm_area_struct *vma = walk->vma;
pte_t *pte;
spinlock_t *ptl;
enum mc_target_type target_type;
union mc_target target;
struct page *page;
ptl = pmd_trans_huge_lock(pmd, vma);
if (ptl) {
if (mc.precharge < HPAGE_PMD_NR) {
spin_unlock(ptl);
return 0;
}
target_type = get_mctgt_type_thp(vma, addr, *pmd, &target);
if (target_type == MC_TARGET_PAGE) {
page = target.page;
if (isolate_lru_page(page)) {
if (!mem_cgroup_move_account(page, true,
mc.from, mc.to)) {
mc.precharge -= HPAGE_PMD_NR;
mc.moved_charge += HPAGE_PMD_NR;
}
putback_lru_page(page);
}
unlock_page(page);
put_page(page);
} else if (target_type == MC_TARGET_DEVICE) {
page = target.page;
if (!mem_cgroup_move_account(page, true,
mc.from, mc.to)) {
mc.precharge -= HPAGE_PMD_NR;
mc.moved_charge += HPAGE_PMD_NR;
}
unlock_page(page);
put_page(page);
}
spin_unlock(ptl);
return 0;
}
retry:
pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
if (!pte)
return 0;
for (; addr != end; addr += PAGE_SIZE) {
pte_t ptent = ptep_get(pte++);
bool device = false;
swp_entry_t ent;
if (!mc.precharge)
break;
switch (get_mctgt_type(vma, addr, ptent, &target)) {
case MC_TARGET_DEVICE:
device = true;
fallthrough;
case MC_TARGET_PAGE:
page = target.page;
/*
* We can have a part of the split pmd here. Moving it
* can be done but it would be too convoluted so simply
* ignore such a partial THP and keep it in original
* memcg. There should be somebody mapping the head.
*/
if (PageTransCompound(page))
goto put;
if (!device && !isolate_lru_page(page))
goto put;
if (!mem_cgroup_move_account(page, false,
mc.from, mc.to)) {
mc.precharge--;
/* we uncharge from mc.from later. */
mc.moved_charge++;
}
if (!device)
putback_lru_page(page);
put: /* get_mctgt_type() gets & locks the page */
unlock_page(page);
put_page(page);
break;
case MC_TARGET_SWAP:
ent = target.ent;
if (!mem_cgroup_move_swap_account(ent, mc.from, mc.to)) {
mc.precharge--;
mem_cgroup_id_get_many(mc.to, 1);
/* we fixup other refcnts and charges later. */
mc.moved_swap++;
}
break;
default:
break;
}
}
pte_unmap_unlock(pte - 1, ptl);
cond_resched();
if (addr != end) {
/*
* We have consumed all precharges we got in can_attach().
* We try charge one by one, but don't do any additional
* charges to mc.to if we have failed in charge once in attach()
* phase.
*/
ret = mem_cgroup_do_precharge(1);
if (!ret)
goto retry;
}
return ret;
}
static const struct mm_walk_ops charge_walk_ops = {
.pmd_entry = mem_cgroup_move_charge_pte_range,
.walk_lock = PGWALK_RDLOCK,
};
static void mem_cgroup_move_charge(void)
{
lru_add_drain_all();
/*
* Signal folio_memcg_lock() to take the memcg's move_lock
* while we're moving its pages to another memcg. Then wait
* for already started RCU-only updates to finish.
*/
atomic_inc(&mc.from->moving_account);
synchronize_rcu();
retry:
if (unlikely(!mmap_read_trylock(mc.mm))) {
/*
* Someone who are holding the mmap_lock might be waiting in
* waitq. So we cancel all extra charges, wake up all waiters,
* and retry. Because we cancel precharges, we might not be able
* to move enough charges, but moving charge is a best-effort
* feature anyway, so it wouldn't be a big problem.
*/
__mem_cgroup_clear_mc();
cond_resched();
goto retry;
}
/*
* When we have consumed all precharges and failed in doing
* additional charge, the page walk just aborts.
*/
walk_page_range(mc.mm, 0, ULONG_MAX, &charge_walk_ops, NULL);
mmap_read_unlock(mc.mm);
atomic_dec(&mc.from->moving_account);
}
static void mem_cgroup_move_task(void)
{
if (mc.to) {
mem_cgroup_move_charge();
mem_cgroup_clear_mc();
}
}
#else /* !CONFIG_MMU */
static int mem_cgroup_can_attach(struct cgroup_taskset *tset)
{
return 0;
}
static void mem_cgroup_cancel_attach(struct cgroup_taskset *tset)
{
}
static void mem_cgroup_move_task(void)
{
}
#endif
#ifdef CONFIG_LRU_GEN
static void mem_cgroup_attach(struct cgroup_taskset *tset)
{
struct task_struct *task;
struct cgroup_subsys_state *css;
/* find the first leader if there is any */
cgroup_taskset_for_each_leader(task, css, tset)
break;
if (!task)
return;
task_lock(task);
if (task->mm && READ_ONCE(task->mm->owner) == task)
lru_gen_migrate_mm(task->mm);
task_unlock(task);
}
#else
static void mem_cgroup_attach(struct cgroup_taskset *tset)
{
}
#endif /* CONFIG_LRU_GEN */
static int seq_puts_memcg_tunable(struct seq_file *m, unsigned long value)
{
if (value == PAGE_COUNTER_MAX)
seq_puts(m, "max\n");
else
seq_printf(m, "%llu\n", (u64)value * PAGE_SIZE);
return 0;
}
static u64 memory_current_read(struct cgroup_subsys_state *css,
struct cftype *cft)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
return (u64)page_counter_read(&memcg->memory) * PAGE_SIZE;
}
static u64 memory_peak_read(struct cgroup_subsys_state *css,
struct cftype *cft)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
return (u64)memcg->memory.watermark * PAGE_SIZE;
}
static int memory_min_show(struct seq_file *m, void *v)
{
return seq_puts_memcg_tunable(m,
READ_ONCE(mem_cgroup_from_seq(m)->memory.min));
}
static ssize_t memory_min_write(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
unsigned long min;
int err;
buf = strstrip(buf);
err = page_counter_memparse(buf, "max", &min);
if (err)
return err;
page_counter_set_min(&memcg->memory, min);
return nbytes;
}
static int memory_low_show(struct seq_file *m, void *v)
{
return seq_puts_memcg_tunable(m,
READ_ONCE(mem_cgroup_from_seq(m)->memory.low));
}
static ssize_t memory_low_write(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
unsigned long low;
int err;
buf = strstrip(buf);
err = page_counter_memparse(buf, "max", &low);
if (err)
return err;
page_counter_set_low(&memcg->memory, low);
return nbytes;
}
static int memory_high_show(struct seq_file *m, void *v)
{
return seq_puts_memcg_tunable(m,
READ_ONCE(mem_cgroup_from_seq(m)->memory.high));
}
static ssize_t memory_high_write(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
unsigned int nr_retries = MAX_RECLAIM_RETRIES;
bool drained = false;
unsigned long high;
int err;
buf = strstrip(buf);
err = page_counter_memparse(buf, "max", &high);
if (err)
return err;
page_counter_set_high(&memcg->memory, high);
for (;;) {
unsigned long nr_pages = page_counter_read(&memcg->memory);
unsigned long reclaimed;
if (nr_pages <= high)
break;
if (signal_pending(current))
break;
if (!drained) {
drain_all_stock(memcg);
drained = true;
continue;
}
reclaimed = try_to_free_mem_cgroup_pages(memcg, nr_pages - high,
GFP_KERNEL, MEMCG_RECLAIM_MAY_SWAP);
if (!reclaimed && !nr_retries--)
break;
}
memcg_wb_domain_size_changed(memcg);
return nbytes;
}
static int memory_max_show(struct seq_file *m, void *v)
{
return seq_puts_memcg_tunable(m,
READ_ONCE(mem_cgroup_from_seq(m)->memory.max));
}
static ssize_t memory_max_write(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
unsigned int nr_reclaims = MAX_RECLAIM_RETRIES;
bool drained = false;
unsigned long max;
int err;
buf = strstrip(buf);
err = page_counter_memparse(buf, "max", &max);
if (err)
return err;
xchg(&memcg->memory.max, max);
for (;;) {
unsigned long nr_pages = page_counter_read(&memcg->memory);
if (nr_pages <= max)
break;
if (signal_pending(current))
break;
if (!drained) {
drain_all_stock(memcg);
drained = true;
continue;
}
if (nr_reclaims) {
if (!try_to_free_mem_cgroup_pages(memcg, nr_pages - max,
GFP_KERNEL, MEMCG_RECLAIM_MAY_SWAP))
nr_reclaims--;
continue;
}
memcg_memory_event(memcg, MEMCG_OOM);
if (!mem_cgroup_out_of_memory(memcg, GFP_KERNEL, 0))
break;
}
memcg_wb_domain_size_changed(memcg);
return nbytes;
}
static void __memory_events_show(struct seq_file *m, atomic_long_t *events)
{
seq_printf(m, "low %lu\n", atomic_long_read(&events[MEMCG_LOW]));
seq_printf(m, "high %lu\n", atomic_long_read(&events[MEMCG_HIGH]));
seq_printf(m, "max %lu\n", atomic_long_read(&events[MEMCG_MAX]));
seq_printf(m, "oom %lu\n", atomic_long_read(&events[MEMCG_OOM]));
seq_printf(m, "oom_kill %lu\n",
atomic_long_read(&events[MEMCG_OOM_KILL]));
seq_printf(m, "oom_group_kill %lu\n",
atomic_long_read(&events[MEMCG_OOM_GROUP_KILL]));
}
static int memory_events_show(struct seq_file *m, void *v)
{
struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
__memory_events_show(m, memcg->memory_events);
return 0;
}
static int memory_events_local_show(struct seq_file *m, void *v)
{
struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
__memory_events_show(m, memcg->memory_events_local);
return 0;
}
static int memory_stat_show(struct seq_file *m, void *v)
{
struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
char *buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
struct seq_buf s;
if (!buf)
return -ENOMEM;
seq_buf_init(&s, buf, PAGE_SIZE);
memory_stat_format(memcg, &s);
seq_puts(m, buf);
kfree(buf);
return 0;
}
#ifdef CONFIG_NUMA
static inline unsigned long lruvec_page_state_output(struct lruvec *lruvec,
int item)
{
return lruvec_page_state(lruvec, item) * memcg_page_state_unit(item);
}
static int memory_numa_stat_show(struct seq_file *m, void *v)
{
int i;
struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
mem_cgroup_flush_stats();
for (i = 0; i < ARRAY_SIZE(memory_stats); i++) {
int nid;
if (memory_stats[i].idx >= NR_VM_NODE_STAT_ITEMS)
continue;
seq_printf(m, "%s", memory_stats[i].name);
for_each_node_state(nid, N_MEMORY) {
u64 size;
struct lruvec *lruvec;
lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(nid));
size = lruvec_page_state_output(lruvec,
memory_stats[i].idx);
seq_printf(m, " N%d=%llu", nid, size);
}
seq_putc(m, '\n');
}
return 0;
}
#endif
static int memory_oom_group_show(struct seq_file *m, void *v)
{
struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
seq_printf(m, "%d\n", READ_ONCE(memcg->oom_group));
return 0;
}
static ssize_t memory_oom_group_write(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
int ret, oom_group;
buf = strstrip(buf);
if (!buf)
return -EINVAL;
ret = kstrtoint(buf, 0, &oom_group);
if (ret)
return ret;
if (oom_group != 0 && oom_group != 1)
return -EINVAL;
WRITE_ONCE(memcg->oom_group, oom_group);
return nbytes;
}
static ssize_t memory_reclaim(struct kernfs_open_file *of, char *buf,
size_t nbytes, loff_t off)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
unsigned int nr_retries = MAX_RECLAIM_RETRIES;
unsigned long nr_to_reclaim, nr_reclaimed = 0;
unsigned int reclaim_options;
int err;
buf = strstrip(buf);
err = page_counter_memparse(buf, "", &nr_to_reclaim);
if (err)
return err;
reclaim_options = MEMCG_RECLAIM_MAY_SWAP | MEMCG_RECLAIM_PROACTIVE;
while (nr_reclaimed < nr_to_reclaim) {
unsigned long reclaimed;
if (signal_pending(current))
return -EINTR;
/*
* This is the final attempt, drain percpu lru caches in the
* hope of introducing more evictable pages for
* try_to_free_mem_cgroup_pages().
*/
if (!nr_retries)
lru_add_drain_all();
reclaimed = try_to_free_mem_cgroup_pages(memcg,
min(nr_to_reclaim - nr_reclaimed, SWAP_CLUSTER_MAX),
GFP_KERNEL, reclaim_options);
if (!reclaimed && !nr_retries--)
return -EAGAIN;
nr_reclaimed += reclaimed;
}
return nbytes;
}
static struct cftype memory_files[] = {
{
.name = "current",
.flags = CFTYPE_NOT_ON_ROOT,
.read_u64 = memory_current_read,
},
{
.name = "peak",
.flags = CFTYPE_NOT_ON_ROOT,
.read_u64 = memory_peak_read,
},
{
.name = "min",
.flags = CFTYPE_NOT_ON_ROOT,
.seq_show = memory_min_show,
.write = memory_min_write,
},
{
.name = "low",
.flags = CFTYPE_NOT_ON_ROOT,
.seq_show = memory_low_show,
.write = memory_low_write,
},
{
.name = "high",
.flags = CFTYPE_NOT_ON_ROOT,
.seq_show = memory_high_show,
.write = memory_high_write,
},
{
.name = "max",
.flags = CFTYPE_NOT_ON_ROOT,
.seq_show = memory_max_show,
.write = memory_max_write,
},
{
.name = "events",
.flags = CFTYPE_NOT_ON_ROOT,
.file_offset = offsetof(struct mem_cgroup, events_file),
.seq_show = memory_events_show,
},
{
.name = "events.local",
.flags = CFTYPE_NOT_ON_ROOT,
.file_offset = offsetof(struct mem_cgroup, events_local_file),
.seq_show = memory_events_local_show,
},
{
.name = "stat",
.seq_show = memory_stat_show,
},
#ifdef CONFIG_NUMA
{
.name = "numa_stat",
.seq_show = memory_numa_stat_show,
},
#endif
{
.name = "oom.group",
.flags = CFTYPE_NOT_ON_ROOT | CFTYPE_NS_DELEGATABLE,
.seq_show = memory_oom_group_show,
.write = memory_oom_group_write,
},
{
.name = "reclaim",
.flags = CFTYPE_NS_DELEGATABLE,
.write = memory_reclaim,
},
{ } /* terminate */
};
struct cgroup_subsys memory_cgrp_subsys = {
.css_alloc = mem_cgroup_css_alloc,
.css_online = mem_cgroup_css_online,
.css_offline = mem_cgroup_css_offline,
.css_released = mem_cgroup_css_released,
.css_free = mem_cgroup_css_free,
.css_reset = mem_cgroup_css_reset,
.css_rstat_flush = mem_cgroup_css_rstat_flush,
.can_attach = mem_cgroup_can_attach,
.attach = mem_cgroup_attach,
.cancel_attach = mem_cgroup_cancel_attach,
.post_attach = mem_cgroup_move_task,
.dfl_cftypes = memory_files,
.legacy_cftypes = mem_cgroup_legacy_files,
.early_init = 0,
};
/*
* This function calculates an individual cgroup's effective
* protection which is derived from its own memory.min/low, its
* parent's and siblings' settings, as well as the actual memory
* distribution in the tree.
*
* The following rules apply to the effective protection values:
*
* 1. At the first level of reclaim, effective protection is equal to
* the declared protection in memory.min and memory.low.
*
* 2. To enable safe delegation of the protection configuration, at
* subsequent levels the effective protection is capped to the
* parent's effective protection.
*
* 3. To make complex and dynamic subtrees easier to configure, the
* user is allowed to overcommit the declared protection at a given
* level. If that is the case, the parent's effective protection is
* distributed to the children in proportion to how much protection
* they have declared and how much of it they are utilizing.
*
* This makes distribution proportional, but also work-conserving:
* if one cgroup claims much more protection than it uses memory,
* the unused remainder is available to its siblings.
*
* 4. Conversely, when the declared protection is undercommitted at a
* given level, the distribution of the larger parental protection
* budget is NOT proportional. A cgroup's protection from a sibling
* is capped to its own memory.min/low setting.
*
* 5. However, to allow protecting recursive subtrees from each other
* without having to declare each individual cgroup's fixed share
* of the ancestor's claim to protection, any unutilized -
* "floating" - protection from up the tree is distributed in
* proportion to each cgroup's *usage*. This makes the protection
* neutral wrt sibling cgroups and lets them compete freely over
* the shared parental protection budget, but it protects the
* subtree as a whole from neighboring subtrees.
*
* Note that 4. and 5. are not in conflict: 4. is about protecting
* against immediate siblings whereas 5. is about protecting against
* neighboring subtrees.
*/
static unsigned long effective_protection(unsigned long usage,
unsigned long parent_usage,
unsigned long setting,
unsigned long parent_effective,
unsigned long siblings_protected)
{
unsigned long protected;
unsigned long ep;
protected = min(usage, setting);
/*
* If all cgroups at this level combined claim and use more
* protection than what the parent affords them, distribute
* shares in proportion to utilization.
*
* We are using actual utilization rather than the statically
* claimed protection in order to be work-conserving: claimed
* but unused protection is available to siblings that would
* otherwise get a smaller chunk than what they claimed.
*/
if (siblings_protected > parent_effective)
return protected * parent_effective / siblings_protected;
/*
* Ok, utilized protection of all children is within what the
* parent affords them, so we know whatever this child claims
* and utilizes is effectively protected.
*
* If there is unprotected usage beyond this value, reclaim
* will apply pressure in proportion to that amount.
*
* If there is unutilized protection, the cgroup will be fully
* shielded from reclaim, but we do return a smaller value for
* protection than what the group could enjoy in theory. This
* is okay. With the overcommit distribution above, effective
* protection is always dependent on how memory is actually
* consumed among the siblings anyway.
*/
ep = protected;
/*
* If the children aren't claiming (all of) the protection
* afforded to them by the parent, distribute the remainder in
* proportion to the (unprotected) memory of each cgroup. That
* way, cgroups that aren't explicitly prioritized wrt each
* other compete freely over the allowance, but they are
* collectively protected from neighboring trees.
*
* We're using unprotected memory for the weight so that if
* some cgroups DO claim explicit protection, we don't protect
* the same bytes twice.
*
* Check both usage and parent_usage against the respective
* protected values. One should imply the other, but they
* aren't read atomically - make sure the division is sane.
*/
if (!(cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_RECURSIVE_PROT))
return ep;
if (parent_effective > siblings_protected &&
parent_usage > siblings_protected &&
usage > protected) {
unsigned long unclaimed;
unclaimed = parent_effective - siblings_protected;
unclaimed *= usage - protected;
unclaimed /= parent_usage - siblings_protected;
ep += unclaimed;
}
return ep;
}
/**
* mem_cgroup_calculate_protection - check if memory consumption is in the normal range
* @root: the top ancestor of the sub-tree being checked
* @memcg: the memory cgroup to check
*
* WARNING: This function is not stateless! It can only be used as part
* of a top-down tree iteration, not for isolated queries.
*/
void mem_cgroup_calculate_protection(struct mem_cgroup *root,
struct mem_cgroup *memcg)
{
unsigned long usage, parent_usage;
struct mem_cgroup *parent;
if (mem_cgroup_disabled())
return;
if (!root)
root = root_mem_cgroup;
/*
* Effective values of the reclaim targets are ignored so they
* can be stale. Have a look at mem_cgroup_protection for more
* details.
* TODO: calculation should be more robust so that we do not need
* that special casing.
*/
if (memcg == root)
return;
usage = page_counter_read(&memcg->memory);
if (!usage)
return;
parent = parent_mem_cgroup(memcg);
if (parent == root) {
memcg->memory.emin = READ_ONCE(memcg->memory.min);
memcg->memory.elow = READ_ONCE(memcg->memory.low);
return;
}
parent_usage = page_counter_read(&parent->memory);
WRITE_ONCE(memcg->memory.emin, effective_protection(usage, parent_usage,
READ_ONCE(memcg->memory.min),
READ_ONCE(parent->memory.emin),
atomic_long_read(&parent->memory.children_min_usage)));
WRITE_ONCE(memcg->memory.elow, effective_protection(usage, parent_usage,
READ_ONCE(memcg->memory.low),
READ_ONCE(parent->memory.elow),
atomic_long_read(&parent->memory.children_low_usage)));
}
static int charge_memcg(struct folio *folio, struct mem_cgroup *memcg,
gfp_t gfp)
{
long nr_pages = folio_nr_pages(folio);
int ret;
ret = try_charge(memcg, gfp, nr_pages);
if (ret)
goto out;
css_get(&memcg->css);
commit_charge(folio, memcg);
local_irq_disable();
mem_cgroup_charge_statistics(memcg, nr_pages);
memcg_check_events(memcg, folio_nid(folio));
local_irq_enable();
out:
return ret;
}
int __mem_cgroup_charge(struct folio *folio, struct mm_struct *mm, gfp_t gfp)
{
struct mem_cgroup *memcg;
int ret;
memcg = get_mem_cgroup_from_mm(mm);
ret = charge_memcg(folio, memcg, gfp);
css_put(&memcg->css);
return ret;
}
/**
* mem_cgroup_swapin_charge_folio - Charge a newly allocated folio for swapin.
* @folio: folio to charge.
* @mm: mm context of the victim
* @gfp: reclaim mode
* @entry: swap entry for which the folio is allocated
*
* This function charges a folio allocated for swapin. Please call this before
* adding the folio to the swapcache.
*
* Returns 0 on success. Otherwise, an error code is returned.
*/
int mem_cgroup_swapin_charge_folio(struct folio *folio, struct mm_struct *mm,
gfp_t gfp, swp_entry_t entry)
{
struct mem_cgroup *memcg;
unsigned short id;
int ret;
if (mem_cgroup_disabled())
return 0;
id = lookup_swap_cgroup_id(entry);
rcu_read_lock();
memcg = mem_cgroup_from_id(id);
if (!memcg || !css_tryget_online(&memcg->css))
memcg = get_mem_cgroup_from_mm(mm);
rcu_read_unlock();
ret = charge_memcg(folio, memcg, gfp);
css_put(&memcg->css);
return ret;
}
/*
* mem_cgroup_swapin_uncharge_swap - uncharge swap slot
* @entry: swap entry for which the page is charged
*
* Call this function after successfully adding the charged page to swapcache.
*
* Note: This function assumes the page for which swap slot is being uncharged
* is order 0 page.
*/
void mem_cgroup_swapin_uncharge_swap(swp_entry_t entry)
{
/*
* Cgroup1's unified memory+swap counter has been charged with the
* new swapcache page, finish the transfer by uncharging the swap
* slot. The swap slot would also get uncharged when it dies, but
* it can stick around indefinitely and we'd count the page twice
* the entire time.
*
* Cgroup2 has separate resource counters for memory and swap,
* so this is a non-issue here. Memory and swap charge lifetimes
* correspond 1:1 to page and swap slot lifetimes: we charge the
* page to memory here, and uncharge swap when the slot is freed.
*/
if (!mem_cgroup_disabled() && do_memsw_account()) {
/*
* The swap entry might not get freed for a long time,
* let's not wait for it. The page already received a
* memory+swap charge, drop the swap entry duplicate.
*/
mem_cgroup_uncharge_swap(entry, 1);
}
}
struct uncharge_gather {
struct mem_cgroup *memcg;
unsigned long nr_memory;
unsigned long pgpgout;
unsigned long nr_kmem;
int nid;
};
static inline void uncharge_gather_clear(struct uncharge_gather *ug)
{
memset(ug, 0, sizeof(*ug));
}
static void uncharge_batch(const struct uncharge_gather *ug)
{
unsigned long flags;
if (ug->nr_memory) {
page_counter_uncharge(&ug->memcg->memory, ug->nr_memory);
if (do_memsw_account())
page_counter_uncharge(&ug->memcg->memsw, ug->nr_memory);
if (ug->nr_kmem)
memcg_account_kmem(ug->memcg, -ug->nr_kmem);
memcg_oom_recover(ug->memcg);
}
local_irq_save(flags);
__count_memcg_events(ug->memcg, PGPGOUT, ug->pgpgout);
__this_cpu_add(ug->memcg->vmstats_percpu->nr_page_events, ug->nr_memory);
memcg_check_events(ug->memcg, ug->nid);
local_irq_restore(flags);
/* drop reference from uncharge_folio */
css_put(&ug->memcg->css);
}
static void uncharge_folio(struct folio *folio, struct uncharge_gather *ug)
{
long nr_pages;
struct mem_cgroup *memcg;
struct obj_cgroup *objcg;
VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
/*
* Nobody should be changing or seriously looking at
* folio memcg or objcg at this point, we have fully
* exclusive access to the folio.
*/
if (folio_memcg_kmem(folio)) {
objcg = __folio_objcg(folio);
/*
* This get matches the put at the end of the function and
* kmem pages do not hold memcg references anymore.
*/
memcg = get_mem_cgroup_from_objcg(objcg);
} else {
memcg = __folio_memcg(folio);
}
if (!memcg)
return;
if (ug->memcg != memcg) {
if (ug->memcg) {
uncharge_batch(ug);
uncharge_gather_clear(ug);
}
ug->memcg = memcg;
ug->nid = folio_nid(folio);
/* pairs with css_put in uncharge_batch */
css_get(&memcg->css);
}
nr_pages = folio_nr_pages(folio);
if (folio_memcg_kmem(folio)) {
ug->nr_memory += nr_pages;
ug->nr_kmem += nr_pages;
folio->memcg_data = 0;
obj_cgroup_put(objcg);
} else {
/* LRU pages aren't accounted at the root level */
if (!mem_cgroup_is_root(memcg))
ug->nr_memory += nr_pages;
ug->pgpgout++;
folio->memcg_data = 0;
}
css_put(&memcg->css);
}
void __mem_cgroup_uncharge(struct folio *folio)
{
struct uncharge_gather ug;
/* Don't touch folio->lru of any random page, pre-check: */
if (!folio_memcg(folio))
return;
uncharge_gather_clear(&ug);
uncharge_folio(folio, &ug);
uncharge_batch(&ug);
}
/**
* __mem_cgroup_uncharge_list - uncharge a list of page
* @page_list: list of pages to uncharge
*
* Uncharge a list of pages previously charged with
* __mem_cgroup_charge().
*/
void __mem_cgroup_uncharge_list(struct list_head *page_list)
{
struct uncharge_gather ug;
struct folio *folio;
uncharge_gather_clear(&ug);
list_for_each_entry(folio, page_list, lru)
uncharge_folio(folio, &ug);
if (ug.memcg)
uncharge_batch(&ug);
}
/**
* mem_cgroup_migrate - Charge a folio's replacement.
* @old: Currently circulating folio.
* @new: Replacement folio.
*
* Charge @new as a replacement folio for @old. @old will
* be uncharged upon free.
*
* Both folios must be locked, @new->mapping must be set up.
*/
void mem_cgroup_migrate(struct folio *old, struct folio *new)
{
struct mem_cgroup *memcg;
long nr_pages = folio_nr_pages(new);
unsigned long flags;
VM_BUG_ON_FOLIO(!folio_test_locked(old), old);
VM_BUG_ON_FOLIO(!folio_test_locked(new), new);
VM_BUG_ON_FOLIO(folio_test_anon(old) != folio_test_anon(new), new);
VM_BUG_ON_FOLIO(folio_nr_pages(old) != nr_pages, new);
if (mem_cgroup_disabled())
return;
/* Page cache replacement: new folio already charged? */
if (folio_memcg(new))
return;
memcg = folio_memcg(old);
VM_WARN_ON_ONCE_FOLIO(!memcg, old);
if (!memcg)
return;
/* Force-charge the new page. The old one will be freed soon */
if (!mem_cgroup_is_root(memcg)) {
page_counter_charge(&memcg->memory, nr_pages);
if (do_memsw_account())
page_counter_charge(&memcg->memsw, nr_pages);
}
css_get(&memcg->css);
commit_charge(new, memcg);
local_irq_save(flags);
mem_cgroup_charge_statistics(memcg, nr_pages);
memcg_check_events(memcg, folio_nid(new));
local_irq_restore(flags);
}
DEFINE_STATIC_KEY_FALSE(memcg_sockets_enabled_key);
EXPORT_SYMBOL(memcg_sockets_enabled_key);
void mem_cgroup_sk_alloc(struct sock *sk)
{
struct mem_cgroup *memcg;
if (!mem_cgroup_sockets_enabled)
return;
/* Do not associate the sock with unrelated interrupted task's memcg. */
if (!in_task())
return;
rcu_read_lock();
memcg = mem_cgroup_from_task(current);
if (mem_cgroup_is_root(memcg))
goto out;
if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && !memcg->tcpmem_active)
goto out;
if (css_tryget(&memcg->css))
sk->sk_memcg = memcg;
out:
rcu_read_unlock();
}
void mem_cgroup_sk_free(struct sock *sk)
{
if (sk->sk_memcg)
css_put(&sk->sk_memcg->css);
}
/**
* mem_cgroup_charge_skmem - charge socket memory
* @memcg: memcg to charge
* @nr_pages: number of pages to charge
* @gfp_mask: reclaim mode
*
* Charges @nr_pages to @memcg. Returns %true if the charge fit within
* @memcg's configured limit, %false if it doesn't.
*/
bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages,
gfp_t gfp_mask)
{
if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) {
struct page_counter *fail;
if (page_counter_try_charge(&memcg->tcpmem, nr_pages, &fail)) {
memcg->tcpmem_pressure = 0;
return true;
}
memcg->tcpmem_pressure = 1;
if (gfp_mask & __GFP_NOFAIL) {
page_counter_charge(&memcg->tcpmem, nr_pages);
return true;
}
return false;
}
if (try_charge(memcg, gfp_mask, nr_pages) == 0) {
mod_memcg_state(memcg, MEMCG_SOCK, nr_pages);
return true;
}
return false;
}
/**
* mem_cgroup_uncharge_skmem - uncharge socket memory
* @memcg: memcg to uncharge
* @nr_pages: number of pages to uncharge
*/
void mem_cgroup_uncharge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages)
{
if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) {
page_counter_uncharge(&memcg->tcpmem, nr_pages);
return;
}
mod_memcg_state(memcg, MEMCG_SOCK, -nr_pages);
refill_stock(memcg, nr_pages);
}
static int __init cgroup_memory(char *s)
{
char *token;
while ((token = strsep(&s, ",")) != NULL) {
if (!*token)
continue;
if (!strcmp(token, "nosocket"))
cgroup_memory_nosocket = true;
if (!strcmp(token, "nokmem"))
cgroup_memory_nokmem = true;
if (!strcmp(token, "nobpf"))
cgroup_memory_nobpf = true;
}
return 1;
}
__setup("cgroup.memory=", cgroup_memory);
/*
* subsys_initcall() for memory controller.
*
* Some parts like memcg_hotplug_cpu_dead() have to be initialized from this
* context because of lock dependencies (cgroup_lock -> cpu hotplug) but
* basically everything that doesn't depend on a specific mem_cgroup structure
* should be initialized from here.
*/
static int __init mem_cgroup_init(void)
{
int cpu, node;
/*
* Currently s32 type (can refer to struct batched_lruvec_stat) is
* used for per-memcg-per-cpu caching of per-node statistics. In order
* to work fine, we should make sure that the overfill threshold can't
* exceed S32_MAX / PAGE_SIZE.
*/
BUILD_BUG_ON(MEMCG_CHARGE_BATCH > S32_MAX / PAGE_SIZE);
cpuhp_setup_state_nocalls(CPUHP_MM_MEMCQ_DEAD, "mm/memctrl:dead", NULL,
memcg_hotplug_cpu_dead);
for_each_possible_cpu(cpu)
INIT_WORK(&per_cpu_ptr(&memcg_stock, cpu)->work,
drain_local_stock);
for_each_node(node) {
struct mem_cgroup_tree_per_node *rtpn;
rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, node);
rtpn->rb_root = RB_ROOT;
rtpn->rb_rightmost = NULL;
spin_lock_init(&rtpn->lock);
soft_limit_tree.rb_tree_per_node[node] = rtpn;
}
return 0;
}
subsys_initcall(mem_cgroup_init);
#ifdef CONFIG_SWAP
static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg)
{
while (!refcount_inc_not_zero(&memcg->id.ref)) {
/*
* The root cgroup cannot be destroyed, so it's refcount must
* always be >= 1.
*/
if (WARN_ON_ONCE(mem_cgroup_is_root(memcg))) {
VM_BUG_ON(1);
break;
}
memcg = parent_mem_cgroup(memcg);
if (!memcg)
memcg = root_mem_cgroup;
}
return memcg;
}
/**
* mem_cgroup_swapout - transfer a memsw charge to swap
* @folio: folio whose memsw charge to transfer
* @entry: swap entry to move the charge to
*
* Transfer the memsw charge of @folio to @entry.
*/
void mem_cgroup_swapout(struct folio *folio, swp_entry_t entry)
{
struct mem_cgroup *memcg, *swap_memcg;
unsigned int nr_entries;
unsigned short oldid;
VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
VM_BUG_ON_FOLIO(folio_ref_count(folio), folio);
if (mem_cgroup_disabled())
return;
if (!do_memsw_account())
return;
memcg = folio_memcg(folio);
VM_WARN_ON_ONCE_FOLIO(!memcg, folio);
if (!memcg)
return;
/*
* In case the memcg owning these pages has been offlined and doesn't
* have an ID allocated to it anymore, charge the closest online
* ancestor for the swap instead and transfer the memory+swap charge.
*/
swap_memcg = mem_cgroup_id_get_online(memcg);
nr_entries = folio_nr_pages(folio);
/* Get references for the tail pages, too */
if (nr_entries > 1)
mem_cgroup_id_get_many(swap_memcg, nr_entries - 1);
oldid = swap_cgroup_record(entry, mem_cgroup_id(swap_memcg),
nr_entries);
VM_BUG_ON_FOLIO(oldid, folio);
mod_memcg_state(swap_memcg, MEMCG_SWAP, nr_entries);
folio->memcg_data = 0;
if (!mem_cgroup_is_root(memcg))
page_counter_uncharge(&memcg->memory, nr_entries);
if (memcg != swap_memcg) {
if (!mem_cgroup_is_root(swap_memcg))
page_counter_charge(&swap_memcg->memsw, nr_entries);
page_counter_uncharge(&memcg->memsw, nr_entries);
}
/*
* Interrupts should be disabled here because the caller holds the
* i_pages lock which is taken with interrupts-off. It is
* important here to have the interrupts disabled because it is the
* only synchronisation we have for updating the per-CPU variables.
*/
memcg_stats_lock();
mem_cgroup_charge_statistics(memcg, -nr_entries);
memcg_stats_unlock();
memcg_check_events(memcg, folio_nid(folio));
css_put(&memcg->css);
}
/**
* __mem_cgroup_try_charge_swap - try charging swap space for a folio
* @folio: folio being added to swap
* @entry: swap entry to charge
*
* Try to charge @folio's memcg for the swap space at @entry.
*
* Returns 0 on success, -ENOMEM on failure.
*/
int __mem_cgroup_try_charge_swap(struct folio *folio, swp_entry_t entry)
{
unsigned int nr_pages = folio_nr_pages(folio);
struct page_counter *counter;
struct mem_cgroup *memcg;
unsigned short oldid;
if (do_memsw_account())
return 0;
memcg = folio_memcg(folio);
VM_WARN_ON_ONCE_FOLIO(!memcg, folio);
if (!memcg)
return 0;
if (!entry.val) {
memcg_memory_event(memcg, MEMCG_SWAP_FAIL);
return 0;
}
memcg = mem_cgroup_id_get_online(memcg);
if (!mem_cgroup_is_root(memcg) &&
!page_counter_try_charge(&memcg->swap, nr_pages, &counter)) {
memcg_memory_event(memcg, MEMCG_SWAP_MAX);
memcg_memory_event(memcg, MEMCG_SWAP_FAIL);
mem_cgroup_id_put(memcg);
return -ENOMEM;
}
/* Get references for the tail pages, too */
if (nr_pages > 1)
mem_cgroup_id_get_many(memcg, nr_pages - 1);
oldid = swap_cgroup_record(entry, mem_cgroup_id(memcg), nr_pages);
VM_BUG_ON_FOLIO(oldid, folio);
mod_memcg_state(memcg, MEMCG_SWAP, nr_pages);
return 0;
}
/**
* __mem_cgroup_uncharge_swap - uncharge swap space
* @entry: swap entry to uncharge
* @nr_pages: the amount of swap space to uncharge
*/
void __mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages)
{
struct mem_cgroup *memcg;
unsigned short id;
id = swap_cgroup_record(entry, 0, nr_pages);
rcu_read_lock();
memcg = mem_cgroup_from_id(id);
if (memcg) {
if (!mem_cgroup_is_root(memcg)) {
if (do_memsw_account())
page_counter_uncharge(&memcg->memsw, nr_pages);
else
page_counter_uncharge(&memcg->swap, nr_pages);
}
mod_memcg_state(memcg, MEMCG_SWAP, -nr_pages);
mem_cgroup_id_put_many(memcg, nr_pages);
}
rcu_read_unlock();
}
long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg)
{
long nr_swap_pages = get_nr_swap_pages();
if (mem_cgroup_disabled() || do_memsw_account())
return nr_swap_pages;
for (; !mem_cgroup_is_root(memcg); memcg = parent_mem_cgroup(memcg))
nr_swap_pages = min_t(long, nr_swap_pages,
READ_ONCE(memcg->swap.max) -
page_counter_read(&memcg->swap));
return nr_swap_pages;
}
bool mem_cgroup_swap_full(struct folio *folio)
{
struct mem_cgroup *memcg;
VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);
if (vm_swap_full())
return true;
if (do_memsw_account())
return false;
memcg = folio_memcg(folio);
if (!memcg)
return false;
for (; !mem_cgroup_is_root(memcg); memcg = parent_mem_cgroup(memcg)) {
unsigned long usage = page_counter_read(&memcg->swap);
if (usage * 2 >= READ_ONCE(memcg->swap.high) ||
usage * 2 >= READ_ONCE(memcg->swap.max))
return true;
}
return false;
}
static int __init setup_swap_account(char *s)
{
pr_warn_once("The swapaccount= commandline option is deprecated. "
"Please report your usecase to [email protected] if you "
"depend on this functionality.\n");
return 1;
}
__setup("swapaccount=", setup_swap_account);
static u64 swap_current_read(struct cgroup_subsys_state *css,
struct cftype *cft)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
return (u64)page_counter_read(&memcg->swap) * PAGE_SIZE;
}
static u64 swap_peak_read(struct cgroup_subsys_state *css,
struct cftype *cft)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
return (u64)memcg->swap.watermark * PAGE_SIZE;
}
static int swap_high_show(struct seq_file *m, void *v)
{
return seq_puts_memcg_tunable(m,
READ_ONCE(mem_cgroup_from_seq(m)->swap.high));
}
static ssize_t swap_high_write(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
unsigned long high;
int err;
buf = strstrip(buf);
err = page_counter_memparse(buf, "max", &high);
if (err)
return err;
page_counter_set_high(&memcg->swap, high);
return nbytes;
}
static int swap_max_show(struct seq_file *m, void *v)
{
return seq_puts_memcg_tunable(m,
READ_ONCE(mem_cgroup_from_seq(m)->swap.max));
}
static ssize_t swap_max_write(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
unsigned long max;
int err;
buf = strstrip(buf);
err = page_counter_memparse(buf, "max", &max);
if (err)
return err;
xchg(&memcg->swap.max, max);
return nbytes;
}
static int swap_events_show(struct seq_file *m, void *v)
{
struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
seq_printf(m, "high %lu\n",
atomic_long_read(&memcg->memory_events[MEMCG_SWAP_HIGH]));
seq_printf(m, "max %lu\n",
atomic_long_read(&memcg->memory_events[MEMCG_SWAP_MAX]));
seq_printf(m, "fail %lu\n",
atomic_long_read(&memcg->memory_events[MEMCG_SWAP_FAIL]));
return 0;
}
static struct cftype swap_files[] = {
{
.name = "swap.current",
.flags = CFTYPE_NOT_ON_ROOT,
.read_u64 = swap_current_read,
},
{
.name = "swap.high",
.flags = CFTYPE_NOT_ON_ROOT,
.seq_show = swap_high_show,
.write = swap_high_write,
},
{
.name = "swap.max",
.flags = CFTYPE_NOT_ON_ROOT,
.seq_show = swap_max_show,
.write = swap_max_write,
},
{
.name = "swap.peak",
.flags = CFTYPE_NOT_ON_ROOT,
.read_u64 = swap_peak_read,
},
{
.name = "swap.events",
.flags = CFTYPE_NOT_ON_ROOT,
.file_offset = offsetof(struct mem_cgroup, swap_events_file),
.seq_show = swap_events_show,
},
{ } /* terminate */
};
static struct cftype memsw_files[] = {
{
.name = "memsw.usage_in_bytes",
.private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
.read_u64 = mem_cgroup_read_u64,
},
{
.name = "memsw.max_usage_in_bytes",
.private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
.write = mem_cgroup_reset,
.read_u64 = mem_cgroup_read_u64,
},
{
.name = "memsw.limit_in_bytes",
.private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
.write = mem_cgroup_write,
.read_u64 = mem_cgroup_read_u64,
},
{
.name = "memsw.failcnt",
.private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
.write = mem_cgroup_reset,
.read_u64 = mem_cgroup_read_u64,
},
{ }, /* terminate */
};
#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP)
/**
* obj_cgroup_may_zswap - check if this cgroup can zswap
* @objcg: the object cgroup
*
* Check if the hierarchical zswap limit has been reached.
*
* This doesn't check for specific headroom, and it is not atomic
* either. But with zswap, the size of the allocation is only known
* once compression has occured, and this optimistic pre-check avoids
* spending cycles on compression when there is already no room left
* or zswap is disabled altogether somewhere in the hierarchy.
*/
bool obj_cgroup_may_zswap(struct obj_cgroup *objcg)
{
struct mem_cgroup *memcg, *original_memcg;
bool ret = true;
if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
return true;
original_memcg = get_mem_cgroup_from_objcg(objcg);
for (memcg = original_memcg; !mem_cgroup_is_root(memcg);
memcg = parent_mem_cgroup(memcg)) {
unsigned long max = READ_ONCE(memcg->zswap_max);
unsigned long pages;
if (max == PAGE_COUNTER_MAX)
continue;
if (max == 0) {
ret = false;
break;
}
cgroup_rstat_flush(memcg->css.cgroup);
pages = memcg_page_state(memcg, MEMCG_ZSWAP_B) / PAGE_SIZE;
if (pages < max)
continue;
ret = false;
break;
}
mem_cgroup_put(original_memcg);
return ret;
}
/**
* obj_cgroup_charge_zswap - charge compression backend memory
* @objcg: the object cgroup
* @size: size of compressed object
*
* This forces the charge after obj_cgroup_may_zswap() allowed
* compression and storage in zwap for this cgroup to go ahead.
*/
void obj_cgroup_charge_zswap(struct obj_cgroup *objcg, size_t size)
{
struct mem_cgroup *memcg;
if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
return;
VM_WARN_ON_ONCE(!(current->flags & PF_MEMALLOC));
/* PF_MEMALLOC context, charging must succeed */
if (obj_cgroup_charge(objcg, GFP_KERNEL, size))
VM_WARN_ON_ONCE(1);
rcu_read_lock();
memcg = obj_cgroup_memcg(objcg);
mod_memcg_state(memcg, MEMCG_ZSWAP_B, size);
mod_memcg_state(memcg, MEMCG_ZSWAPPED, 1);
rcu_read_unlock();
}
/**
* obj_cgroup_uncharge_zswap - uncharge compression backend memory
* @objcg: the object cgroup
* @size: size of compressed object
*
* Uncharges zswap memory on page in.
*/
void obj_cgroup_uncharge_zswap(struct obj_cgroup *objcg, size_t size)
{
struct mem_cgroup *memcg;
if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
return;
obj_cgroup_uncharge(objcg, size);
rcu_read_lock();
memcg = obj_cgroup_memcg(objcg);
mod_memcg_state(memcg, MEMCG_ZSWAP_B, -size);
mod_memcg_state(memcg, MEMCG_ZSWAPPED, -1);
rcu_read_unlock();
}
static u64 zswap_current_read(struct cgroup_subsys_state *css,
struct cftype *cft)
{
cgroup_rstat_flush(css->cgroup);
return memcg_page_state(mem_cgroup_from_css(css), MEMCG_ZSWAP_B);
}
static int zswap_max_show(struct seq_file *m, void *v)
{
return seq_puts_memcg_tunable(m,
READ_ONCE(mem_cgroup_from_seq(m)->zswap_max));
}
static ssize_t zswap_max_write(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
unsigned long max;
int err;
buf = strstrip(buf);
err = page_counter_memparse(buf, "max", &max);
if (err)
return err;
xchg(&memcg->zswap_max, max);
return nbytes;
}
static struct cftype zswap_files[] = {
{
.name = "zswap.current",
.flags = CFTYPE_NOT_ON_ROOT,
.read_u64 = zswap_current_read,
},
{
.name = "zswap.max",
.flags = CFTYPE_NOT_ON_ROOT,
.seq_show = zswap_max_show,
.write = zswap_max_write,
},
{ } /* terminate */
};
#endif /* CONFIG_MEMCG_KMEM && CONFIG_ZSWAP */
static int __init mem_cgroup_swap_init(void)
{
if (mem_cgroup_disabled())
return 0;
WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys, swap_files));
WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys, memsw_files));
#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP)
WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys, zswap_files));
#endif
return 0;
}
subsys_initcall(mem_cgroup_swap_init);
#endif /* CONFIG_SWAP */
| linux-master | mm/memcontrol.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/pagewalk.h>
#include <linux/ptdump.h>
#include <linux/kasan.h>
#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
/*
* This is an optimization for KASAN=y case. Since all kasan page tables
* eventually point to the kasan_early_shadow_page we could call note_page()
* right away without walking through lower level page tables. This saves
* us dozens of seconds (minutes for 5-level config) while checking for
* W+X mapping or reading kernel_page_tables debugfs file.
*/
static inline int note_kasan_page_table(struct mm_walk *walk,
unsigned long addr)
{
struct ptdump_state *st = walk->private;
st->note_page(st, addr, 4, pte_val(kasan_early_shadow_pte[0]));
walk->action = ACTION_CONTINUE;
return 0;
}
#endif
static int ptdump_pgd_entry(pgd_t *pgd, unsigned long addr,
unsigned long next, struct mm_walk *walk)
{
struct ptdump_state *st = walk->private;
pgd_t val = READ_ONCE(*pgd);
#if CONFIG_PGTABLE_LEVELS > 4 && \
(defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS))
if (pgd_page(val) == virt_to_page(lm_alias(kasan_early_shadow_p4d)))
return note_kasan_page_table(walk, addr);
#endif
if (st->effective_prot)
st->effective_prot(st, 0, pgd_val(val));
if (pgd_leaf(val)) {
st->note_page(st, addr, 0, pgd_val(val));
walk->action = ACTION_CONTINUE;
}
return 0;
}
static int ptdump_p4d_entry(p4d_t *p4d, unsigned long addr,
unsigned long next, struct mm_walk *walk)
{
struct ptdump_state *st = walk->private;
p4d_t val = READ_ONCE(*p4d);
#if CONFIG_PGTABLE_LEVELS > 3 && \
(defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS))
if (p4d_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pud)))
return note_kasan_page_table(walk, addr);
#endif
if (st->effective_prot)
st->effective_prot(st, 1, p4d_val(val));
if (p4d_leaf(val)) {
st->note_page(st, addr, 1, p4d_val(val));
walk->action = ACTION_CONTINUE;
}
return 0;
}
static int ptdump_pud_entry(pud_t *pud, unsigned long addr,
unsigned long next, struct mm_walk *walk)
{
struct ptdump_state *st = walk->private;
pud_t val = READ_ONCE(*pud);
#if CONFIG_PGTABLE_LEVELS > 2 && \
(defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS))
if (pud_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pmd)))
return note_kasan_page_table(walk, addr);
#endif
if (st->effective_prot)
st->effective_prot(st, 2, pud_val(val));
if (pud_leaf(val)) {
st->note_page(st, addr, 2, pud_val(val));
walk->action = ACTION_CONTINUE;
}
return 0;
}
static int ptdump_pmd_entry(pmd_t *pmd, unsigned long addr,
unsigned long next, struct mm_walk *walk)
{
struct ptdump_state *st = walk->private;
pmd_t val = READ_ONCE(*pmd);
#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
if (pmd_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pte)))
return note_kasan_page_table(walk, addr);
#endif
if (st->effective_prot)
st->effective_prot(st, 3, pmd_val(val));
if (pmd_leaf(val)) {
st->note_page(st, addr, 3, pmd_val(val));
walk->action = ACTION_CONTINUE;
}
return 0;
}
static int ptdump_pte_entry(pte_t *pte, unsigned long addr,
unsigned long next, struct mm_walk *walk)
{
struct ptdump_state *st = walk->private;
pte_t val = ptep_get_lockless(pte);
if (st->effective_prot)
st->effective_prot(st, 4, pte_val(val));
st->note_page(st, addr, 4, pte_val(val));
return 0;
}
static int ptdump_hole(unsigned long addr, unsigned long next,
int depth, struct mm_walk *walk)
{
struct ptdump_state *st = walk->private;
st->note_page(st, addr, depth, 0);
return 0;
}
static const struct mm_walk_ops ptdump_ops = {
.pgd_entry = ptdump_pgd_entry,
.p4d_entry = ptdump_p4d_entry,
.pud_entry = ptdump_pud_entry,
.pmd_entry = ptdump_pmd_entry,
.pte_entry = ptdump_pte_entry,
.pte_hole = ptdump_hole,
};
void ptdump_walk_pgd(struct ptdump_state *st, struct mm_struct *mm, pgd_t *pgd)
{
const struct ptdump_range *range = st->range;
mmap_write_lock(mm);
while (range->start != range->end) {
walk_page_range_novma(mm, range->start, range->end,
&ptdump_ops, pgd, st);
range++;
}
mmap_write_unlock(mm);
/* Flush out the last page */
st->note_page(st, 0, -1, 0);
}
| linux-master | mm/ptdump.c |
// SPDX-License-Identifier: GPL-2.0
/*
* mm/fadvise.c
*
* Copyright (C) 2002, Linus Torvalds
*
* 11Jan2003 Andrew Morton
* Initial version.
*/
#include <linux/kernel.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/backing-dev.h>
#include <linux/fadvise.h>
#include <linux/writeback.h>
#include <linux/syscalls.h>
#include <linux/swap.h>
#include <asm/unistd.h>
#include "internal.h"
/*
* POSIX_FADV_WILLNEED could set PG_Referenced, and POSIX_FADV_NOREUSE could
* deactivate the pages and clear PG_Referenced.
*/
int generic_fadvise(struct file *file, loff_t offset, loff_t len, int advice)
{
struct inode *inode;
struct address_space *mapping;
struct backing_dev_info *bdi;
loff_t endbyte; /* inclusive */
pgoff_t start_index;
pgoff_t end_index;
unsigned long nrpages;
inode = file_inode(file);
if (S_ISFIFO(inode->i_mode))
return -ESPIPE;
mapping = file->f_mapping;
if (!mapping || len < 0)
return -EINVAL;
bdi = inode_to_bdi(mapping->host);
if (IS_DAX(inode) || (bdi == &noop_backing_dev_info)) {
switch (advice) {
case POSIX_FADV_NORMAL:
case POSIX_FADV_RANDOM:
case POSIX_FADV_SEQUENTIAL:
case POSIX_FADV_WILLNEED:
case POSIX_FADV_NOREUSE:
case POSIX_FADV_DONTNEED:
/* no bad return value, but ignore advice */
break;
default:
return -EINVAL;
}
return 0;
}
/*
* Careful about overflows. Len == 0 means "as much as possible". Use
* unsigned math because signed overflows are undefined and UBSan
* complains.
*/
endbyte = (u64)offset + (u64)len;
if (!len || endbyte < len)
endbyte = LLONG_MAX;
else
endbyte--; /* inclusive */
switch (advice) {
case POSIX_FADV_NORMAL:
file->f_ra.ra_pages = bdi->ra_pages;
spin_lock(&file->f_lock);
file->f_mode &= ~(FMODE_RANDOM | FMODE_NOREUSE);
spin_unlock(&file->f_lock);
break;
case POSIX_FADV_RANDOM:
spin_lock(&file->f_lock);
file->f_mode |= FMODE_RANDOM;
spin_unlock(&file->f_lock);
break;
case POSIX_FADV_SEQUENTIAL:
file->f_ra.ra_pages = bdi->ra_pages * 2;
spin_lock(&file->f_lock);
file->f_mode &= ~FMODE_RANDOM;
spin_unlock(&file->f_lock);
break;
case POSIX_FADV_WILLNEED:
/* First and last PARTIAL page! */
start_index = offset >> PAGE_SHIFT;
end_index = endbyte >> PAGE_SHIFT;
/* Careful about overflow on the "+1" */
nrpages = end_index - start_index + 1;
if (!nrpages)
nrpages = ~0UL;
force_page_cache_readahead(mapping, file, start_index, nrpages);
break;
case POSIX_FADV_NOREUSE:
spin_lock(&file->f_lock);
file->f_mode |= FMODE_NOREUSE;
spin_unlock(&file->f_lock);
break;
case POSIX_FADV_DONTNEED:
__filemap_fdatawrite_range(mapping, offset, endbyte,
WB_SYNC_NONE);
/*
* First and last FULL page! Partial pages are deliberately
* preserved on the expectation that it is better to preserve
* needed memory than to discard unneeded memory.
*/
start_index = (offset+(PAGE_SIZE-1)) >> PAGE_SHIFT;
end_index = (endbyte >> PAGE_SHIFT);
/*
* The page at end_index will be inclusively discarded according
* by invalidate_mapping_pages(), so subtracting 1 from
* end_index means we will skip the last page. But if endbyte
* is page aligned or is at the end of file, we should not skip
* that page - discarding the last page is safe enough.
*/
if ((endbyte & ~PAGE_MASK) != ~PAGE_MASK &&
endbyte != inode->i_size - 1) {
/* First page is tricky as 0 - 1 = -1, but pgoff_t
* is unsigned, so the end_index >= start_index
* check below would be true and we'll discard the whole
* file cache which is not what was asked.
*/
if (end_index == 0)
break;
end_index--;
}
if (end_index >= start_index) {
unsigned long nr_failed = 0;
/*
* It's common to FADV_DONTNEED right after
* the read or write that instantiates the
* pages, in which case there will be some
* sitting on the local LRU cache. Try to
* avoid the expensive remote drain and the
* second cache tree walk below by flushing
* them out right away.
*/
lru_add_drain();
mapping_try_invalidate(mapping, start_index, end_index,
&nr_failed);
/*
* The failures may be due to the folio being
* in the LRU cache of a remote CPU. Drain all
* caches and try again.
*/
if (nr_failed) {
lru_add_drain_all();
invalidate_mapping_pages(mapping, start_index,
end_index);
}
}
break;
default:
return -EINVAL;
}
return 0;
}
EXPORT_SYMBOL(generic_fadvise);
int vfs_fadvise(struct file *file, loff_t offset, loff_t len, int advice)
{
if (file->f_op->fadvise)
return file->f_op->fadvise(file, offset, len, advice);
return generic_fadvise(file, offset, len, advice);
}
EXPORT_SYMBOL(vfs_fadvise);
#ifdef CONFIG_ADVISE_SYSCALLS
int ksys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice)
{
struct fd f = fdget(fd);
int ret;
if (!f.file)
return -EBADF;
ret = vfs_fadvise(f.file, offset, len, advice);
fdput(f);
return ret;
}
SYSCALL_DEFINE4(fadvise64_64, int, fd, loff_t, offset, loff_t, len, int, advice)
{
return ksys_fadvise64_64(fd, offset, len, advice);
}
#ifdef __ARCH_WANT_SYS_FADVISE64
SYSCALL_DEFINE4(fadvise64, int, fd, loff_t, offset, size_t, len, int, advice)
{
return ksys_fadvise64_64(fd, offset, len, advice);
}
#endif
#if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_FADVISE64_64)
COMPAT_SYSCALL_DEFINE6(fadvise64_64, int, fd, compat_arg_u64_dual(offset),
compat_arg_u64_dual(len), int, advice)
{
return ksys_fadvise64_64(fd, compat_arg_u64_glue(offset),
compat_arg_u64_glue(len), advice);
}
#endif
#endif
| linux-master | mm/fadvise.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/mm_types.h>
#include <linux/maple_tree.h>
#include <linux/rwsem.h>
#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/cpumask.h>
#include <linux/mman.h>
#include <linux/pgtable.h>
#include <linux/atomic.h>
#include <linux/user_namespace.h>
#include <linux/iommu.h>
#include <asm/mmu.h>
#ifndef INIT_MM_CONTEXT
#define INIT_MM_CONTEXT(name)
#endif
const struct vm_operations_struct vma_dummy_vm_ops;
/*
* For dynamically allocated mm_structs, there is a dynamically sized cpumask
* at the end of the structure, the size of which depends on the maximum CPU
* number the system can see. That way we allocate only as much memory for
* mm_cpumask() as needed for the hundreds, or thousands of processes that
* a system typically runs.
*
* Since there is only one init_mm in the entire system, keep it simple
* and size this cpu_bitmask to NR_CPUS.
*/
struct mm_struct init_mm = {
.mm_mt = MTREE_INIT_EXT(mm_mt, MM_MT_FLAGS, init_mm.mmap_lock),
.pgd = swapper_pg_dir,
.mm_users = ATOMIC_INIT(2),
.mm_count = ATOMIC_INIT(1),
.write_protect_seq = SEQCNT_ZERO(init_mm.write_protect_seq),
MMAP_LOCK_INITIALIZER(init_mm)
.page_table_lock = __SPIN_LOCK_UNLOCKED(init_mm.page_table_lock),
.arg_lock = __SPIN_LOCK_UNLOCKED(init_mm.arg_lock),
.mmlist = LIST_HEAD_INIT(init_mm.mmlist),
#ifdef CONFIG_PER_VMA_LOCK
.mm_lock_seq = 0,
#endif
.user_ns = &init_user_ns,
.cpu_bitmap = CPU_BITS_NONE,
#ifdef CONFIG_IOMMU_SVA
.pasid = IOMMU_PASID_INVALID,
#endif
INIT_MM_CONTEXT(init_mm)
};
void setup_initial_init_mm(void *start_code, void *end_code,
void *end_data, void *brk)
{
init_mm.start_code = (unsigned long)start_code;
init_mm.end_code = (unsigned long)end_code;
init_mm.end_data = (unsigned long)end_data;
init_mm.brk = (unsigned long)brk;
}
| linux-master | mm/init-mm.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Test cases for KFENCE memory safety error detector. Since the interface with
* which KFENCE's reports are obtained is via the console, this is the output we
* should verify. For each test case checks the presence (or absence) of
* generated reports. Relies on 'console' tracepoint to capture reports as they
* appear in the kernel log.
*
* Copyright (C) 2020, Google LLC.
* Author: Alexander Potapenko <[email protected]>
* Marco Elver <[email protected]>
*/
#include <kunit/test.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/kfence.h>
#include <linux/mm.h>
#include <linux/random.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/tracepoint.h>
#include <trace/events/printk.h>
#include <asm/kfence.h>
#include "kfence.h"
/* May be overridden by <asm/kfence.h>. */
#ifndef arch_kfence_test_address
#define arch_kfence_test_address(addr) (addr)
#endif
#define KFENCE_TEST_REQUIRES(test, cond) do { \
if (!(cond)) \
kunit_skip((test), "Test requires: " #cond); \
} while (0)
/* Report as observed from console. */
static struct {
spinlock_t lock;
int nlines;
char lines[2][256];
} observed = {
.lock = __SPIN_LOCK_UNLOCKED(observed.lock),
};
/* Probe for console output: obtains observed lines of interest. */
static void probe_console(void *ignore, const char *buf, size_t len)
{
unsigned long flags;
int nlines;
spin_lock_irqsave(&observed.lock, flags);
nlines = observed.nlines;
if (strnstr(buf, "BUG: KFENCE: ", len) && strnstr(buf, "test_", len)) {
/*
* KFENCE report and related to the test.
*
* The provided @buf is not NUL-terminated; copy no more than
* @len bytes and let strscpy() add the missing NUL-terminator.
*/
strscpy(observed.lines[0], buf, min(len + 1, sizeof(observed.lines[0])));
nlines = 1;
} else if (nlines == 1 && (strnstr(buf, "at 0x", len) || strnstr(buf, "of 0x", len))) {
strscpy(observed.lines[nlines++], buf, min(len + 1, sizeof(observed.lines[0])));
}
WRITE_ONCE(observed.nlines, nlines); /* Publish new nlines. */
spin_unlock_irqrestore(&observed.lock, flags);
}
/* Check if a report related to the test exists. */
static bool report_available(void)
{
return READ_ONCE(observed.nlines) == ARRAY_SIZE(observed.lines);
}
/* Information we expect in a report. */
struct expect_report {
enum kfence_error_type type; /* The type or error. */
void *fn; /* Function pointer to expected function where access occurred. */
char *addr; /* Address at which the bad access occurred. */
bool is_write; /* Is access a write. */
};
static const char *get_access_type(const struct expect_report *r)
{
return r->is_write ? "write" : "read";
}
/* Check observed report matches information in @r. */
static bool report_matches(const struct expect_report *r)
{
unsigned long addr = (unsigned long)r->addr;
bool ret = false;
unsigned long flags;
typeof(observed.lines) expect;
const char *end;
char *cur;
/* Doubled-checked locking. */
if (!report_available())
return false;
/* Generate expected report contents. */
/* Title */
cur = expect[0];
end = &expect[0][sizeof(expect[0]) - 1];
switch (r->type) {
case KFENCE_ERROR_OOB:
cur += scnprintf(cur, end - cur, "BUG: KFENCE: out-of-bounds %s",
get_access_type(r));
break;
case KFENCE_ERROR_UAF:
cur += scnprintf(cur, end - cur, "BUG: KFENCE: use-after-free %s",
get_access_type(r));
break;
case KFENCE_ERROR_CORRUPTION:
cur += scnprintf(cur, end - cur, "BUG: KFENCE: memory corruption");
break;
case KFENCE_ERROR_INVALID:
cur += scnprintf(cur, end - cur, "BUG: KFENCE: invalid %s",
get_access_type(r));
break;
case KFENCE_ERROR_INVALID_FREE:
cur += scnprintf(cur, end - cur, "BUG: KFENCE: invalid free");
break;
}
scnprintf(cur, end - cur, " in %pS", r->fn);
/* The exact offset won't match, remove it; also strip module name. */
cur = strchr(expect[0], '+');
if (cur)
*cur = '\0';
/* Access information */
cur = expect[1];
end = &expect[1][sizeof(expect[1]) - 1];
switch (r->type) {
case KFENCE_ERROR_OOB:
cur += scnprintf(cur, end - cur, "Out-of-bounds %s at", get_access_type(r));
addr = arch_kfence_test_address(addr);
break;
case KFENCE_ERROR_UAF:
cur += scnprintf(cur, end - cur, "Use-after-free %s at", get_access_type(r));
addr = arch_kfence_test_address(addr);
break;
case KFENCE_ERROR_CORRUPTION:
cur += scnprintf(cur, end - cur, "Corrupted memory at");
break;
case KFENCE_ERROR_INVALID:
cur += scnprintf(cur, end - cur, "Invalid %s at", get_access_type(r));
addr = arch_kfence_test_address(addr);
break;
case KFENCE_ERROR_INVALID_FREE:
cur += scnprintf(cur, end - cur, "Invalid free of");
break;
}
cur += scnprintf(cur, end - cur, " 0x%p", (void *)addr);
spin_lock_irqsave(&observed.lock, flags);
if (!report_available())
goto out; /* A new report is being captured. */
/* Finally match expected output to what we actually observed. */
ret = strstr(observed.lines[0], expect[0]) && strstr(observed.lines[1], expect[1]);
out:
spin_unlock_irqrestore(&observed.lock, flags);
return ret;
}
/* ===== Test cases ===== */
#define TEST_PRIV_WANT_MEMCACHE ((void *)1)
/* Cache used by tests; if NULL, allocate from kmalloc instead. */
static struct kmem_cache *test_cache;
static size_t setup_test_cache(struct kunit *test, size_t size, slab_flags_t flags,
void (*ctor)(void *))
{
if (test->priv != TEST_PRIV_WANT_MEMCACHE)
return size;
kunit_info(test, "%s: size=%zu, ctor=%ps\n", __func__, size, ctor);
/*
* Use SLAB_NO_MERGE to prevent merging with existing caches.
* Use SLAB_ACCOUNT to allocate via memcg, if enabled.
*/
flags |= SLAB_NO_MERGE | SLAB_ACCOUNT;
test_cache = kmem_cache_create("test", size, 1, flags, ctor);
KUNIT_ASSERT_TRUE_MSG(test, test_cache, "could not create cache");
return size;
}
static void test_cache_destroy(void)
{
if (!test_cache)
return;
kmem_cache_destroy(test_cache);
test_cache = NULL;
}
static inline size_t kmalloc_cache_alignment(size_t size)
{
/* just to get ->align so no need to pass in the real caller */
enum kmalloc_cache_type type = kmalloc_type(GFP_KERNEL, 0);
return kmalloc_caches[type][__kmalloc_index(size, false)]->align;
}
/* Must always inline to match stack trace against caller. */
static __always_inline void test_free(void *ptr)
{
if (test_cache)
kmem_cache_free(test_cache, ptr);
else
kfree(ptr);
}
/*
* If this should be a KFENCE allocation, and on which side the allocation and
* the closest guard page should be.
*/
enum allocation_policy {
ALLOCATE_ANY, /* KFENCE, any side. */
ALLOCATE_LEFT, /* KFENCE, left side of page. */
ALLOCATE_RIGHT, /* KFENCE, right side of page. */
ALLOCATE_NONE, /* No KFENCE allocation. */
};
/*
* Try to get a guarded allocation from KFENCE. Uses either kmalloc() or the
* current test_cache if set up.
*/
static void *test_alloc(struct kunit *test, size_t size, gfp_t gfp, enum allocation_policy policy)
{
void *alloc;
unsigned long timeout, resched_after;
const char *policy_name;
switch (policy) {
case ALLOCATE_ANY:
policy_name = "any";
break;
case ALLOCATE_LEFT:
policy_name = "left";
break;
case ALLOCATE_RIGHT:
policy_name = "right";
break;
case ALLOCATE_NONE:
policy_name = "none";
break;
}
kunit_info(test, "%s: size=%zu, gfp=%x, policy=%s, cache=%i\n", __func__, size, gfp,
policy_name, !!test_cache);
/*
* 100x the sample interval should be more than enough to ensure we get
* a KFENCE allocation eventually.
*/
timeout = jiffies + msecs_to_jiffies(100 * kfence_sample_interval);
/*
* Especially for non-preemption kernels, ensure the allocation-gate
* timer can catch up: after @resched_after, every failed allocation
* attempt yields, to ensure the allocation-gate timer is scheduled.
*/
resched_after = jiffies + msecs_to_jiffies(kfence_sample_interval);
do {
if (test_cache)
alloc = kmem_cache_alloc(test_cache, gfp);
else
alloc = kmalloc(size, gfp);
if (is_kfence_address(alloc)) {
struct slab *slab = virt_to_slab(alloc);
enum kmalloc_cache_type type = kmalloc_type(GFP_KERNEL, _RET_IP_);
struct kmem_cache *s = test_cache ?:
kmalloc_caches[type][__kmalloc_index(size, false)];
/*
* Verify that various helpers return the right values
* even for KFENCE objects; these are required so that
* memcg accounting works correctly.
*/
KUNIT_EXPECT_EQ(test, obj_to_index(s, slab, alloc), 0U);
KUNIT_EXPECT_EQ(test, objs_per_slab(s, slab), 1);
if (policy == ALLOCATE_ANY)
return alloc;
if (policy == ALLOCATE_LEFT && PAGE_ALIGNED(alloc))
return alloc;
if (policy == ALLOCATE_RIGHT && !PAGE_ALIGNED(alloc))
return alloc;
} else if (policy == ALLOCATE_NONE)
return alloc;
test_free(alloc);
if (time_after(jiffies, resched_after))
cond_resched();
} while (time_before(jiffies, timeout));
KUNIT_ASSERT_TRUE_MSG(test, false, "failed to allocate from KFENCE");
return NULL; /* Unreachable. */
}
static void test_out_of_bounds_read(struct kunit *test)
{
size_t size = 32;
struct expect_report expect = {
.type = KFENCE_ERROR_OOB,
.fn = test_out_of_bounds_read,
.is_write = false,
};
char *buf;
setup_test_cache(test, size, 0, NULL);
/*
* If we don't have our own cache, adjust based on alignment, so that we
* actually access guard pages on either side.
*/
if (!test_cache)
size = kmalloc_cache_alignment(size);
/* Test both sides. */
buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_LEFT);
expect.addr = buf - 1;
READ_ONCE(*expect.addr);
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
test_free(buf);
buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_RIGHT);
expect.addr = buf + size;
READ_ONCE(*expect.addr);
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
test_free(buf);
}
static void test_out_of_bounds_write(struct kunit *test)
{
size_t size = 32;
struct expect_report expect = {
.type = KFENCE_ERROR_OOB,
.fn = test_out_of_bounds_write,
.is_write = true,
};
char *buf;
setup_test_cache(test, size, 0, NULL);
buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_LEFT);
expect.addr = buf - 1;
WRITE_ONCE(*expect.addr, 42);
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
test_free(buf);
}
static void test_use_after_free_read(struct kunit *test)
{
const size_t size = 32;
struct expect_report expect = {
.type = KFENCE_ERROR_UAF,
.fn = test_use_after_free_read,
.is_write = false,
};
setup_test_cache(test, size, 0, NULL);
expect.addr = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY);
test_free(expect.addr);
READ_ONCE(*expect.addr);
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
}
static void test_double_free(struct kunit *test)
{
const size_t size = 32;
struct expect_report expect = {
.type = KFENCE_ERROR_INVALID_FREE,
.fn = test_double_free,
};
setup_test_cache(test, size, 0, NULL);
expect.addr = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY);
test_free(expect.addr);
test_free(expect.addr); /* Double-free. */
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
}
static void test_invalid_addr_free(struct kunit *test)
{
const size_t size = 32;
struct expect_report expect = {
.type = KFENCE_ERROR_INVALID_FREE,
.fn = test_invalid_addr_free,
};
char *buf;
setup_test_cache(test, size, 0, NULL);
buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY);
expect.addr = buf + 1; /* Free on invalid address. */
test_free(expect.addr); /* Invalid address free. */
test_free(buf); /* No error. */
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
}
static void test_corruption(struct kunit *test)
{
size_t size = 32;
struct expect_report expect = {
.type = KFENCE_ERROR_CORRUPTION,
.fn = test_corruption,
};
char *buf;
setup_test_cache(test, size, 0, NULL);
/* Test both sides. */
buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_LEFT);
expect.addr = buf + size;
WRITE_ONCE(*expect.addr, 42);
test_free(buf);
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_RIGHT);
expect.addr = buf - 1;
WRITE_ONCE(*expect.addr, 42);
test_free(buf);
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
}
/*
* KFENCE is unable to detect an OOB if the allocation's alignment requirements
* leave a gap between the object and the guard page. Specifically, an
* allocation of e.g. 73 bytes is aligned on 8 and 128 bytes for SLUB or SLAB
* respectively. Therefore it is impossible for the allocated object to
* contiguously line up with the right guard page.
*
* However, we test that an access to memory beyond the gap results in KFENCE
* detecting an OOB access.
*/
static void test_kmalloc_aligned_oob_read(struct kunit *test)
{
const size_t size = 73;
const size_t align = kmalloc_cache_alignment(size);
struct expect_report expect = {
.type = KFENCE_ERROR_OOB,
.fn = test_kmalloc_aligned_oob_read,
.is_write = false,
};
char *buf;
buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_RIGHT);
/*
* The object is offset to the right, so there won't be an OOB to the
* left of it.
*/
READ_ONCE(*(buf - 1));
KUNIT_EXPECT_FALSE(test, report_available());
/*
* @buf must be aligned on @align, therefore buf + size belongs to the
* same page -> no OOB.
*/
READ_ONCE(*(buf + size));
KUNIT_EXPECT_FALSE(test, report_available());
/* Overflowing by @align bytes will result in an OOB. */
expect.addr = buf + size + align;
READ_ONCE(*expect.addr);
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
test_free(buf);
}
static void test_kmalloc_aligned_oob_write(struct kunit *test)
{
const size_t size = 73;
struct expect_report expect = {
.type = KFENCE_ERROR_CORRUPTION,
.fn = test_kmalloc_aligned_oob_write,
};
char *buf;
buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_RIGHT);
/*
* The object is offset to the right, so we won't get a page
* fault immediately after it.
*/
expect.addr = buf + size;
WRITE_ONCE(*expect.addr, READ_ONCE(*expect.addr) + 1);
KUNIT_EXPECT_FALSE(test, report_available());
test_free(buf);
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
}
/* Test cache shrinking and destroying with KFENCE. */
static void test_shrink_memcache(struct kunit *test)
{
const size_t size = 32;
void *buf;
setup_test_cache(test, size, 0, NULL);
KUNIT_EXPECT_TRUE(test, test_cache);
buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY);
kmem_cache_shrink(test_cache);
test_free(buf);
KUNIT_EXPECT_FALSE(test, report_available());
}
static void ctor_set_x(void *obj)
{
/* Every object has at least 8 bytes. */
memset(obj, 'x', 8);
}
/* Ensure that SL*B does not modify KFENCE objects on bulk free. */
static void test_free_bulk(struct kunit *test)
{
int iter;
for (iter = 0; iter < 5; iter++) {
const size_t size = setup_test_cache(test, get_random_u32_inclusive(8, 307),
0, (iter & 1) ? ctor_set_x : NULL);
void *objects[] = {
test_alloc(test, size, GFP_KERNEL, ALLOCATE_RIGHT),
test_alloc(test, size, GFP_KERNEL, ALLOCATE_NONE),
test_alloc(test, size, GFP_KERNEL, ALLOCATE_LEFT),
test_alloc(test, size, GFP_KERNEL, ALLOCATE_NONE),
test_alloc(test, size, GFP_KERNEL, ALLOCATE_NONE),
};
kmem_cache_free_bulk(test_cache, ARRAY_SIZE(objects), objects);
KUNIT_ASSERT_FALSE(test, report_available());
test_cache_destroy();
}
}
/* Test init-on-free works. */
static void test_init_on_free(struct kunit *test)
{
const size_t size = 32;
struct expect_report expect = {
.type = KFENCE_ERROR_UAF,
.fn = test_init_on_free,
.is_write = false,
};
int i;
KFENCE_TEST_REQUIRES(test, IS_ENABLED(CONFIG_INIT_ON_FREE_DEFAULT_ON));
/* Assume it hasn't been disabled on command line. */
setup_test_cache(test, size, 0, NULL);
expect.addr = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY);
for (i = 0; i < size; i++)
expect.addr[i] = i + 1;
test_free(expect.addr);
for (i = 0; i < size; i++) {
/*
* This may fail if the page was recycled by KFENCE and then
* written to again -- this however, is near impossible with a
* default config.
*/
KUNIT_EXPECT_EQ(test, expect.addr[i], (char)0);
if (!i) /* Only check first access to not fail test if page is ever re-protected. */
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
}
}
/* Ensure that constructors work properly. */
static void test_memcache_ctor(struct kunit *test)
{
const size_t size = 32;
char *buf;
int i;
setup_test_cache(test, size, 0, ctor_set_x);
buf = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY);
for (i = 0; i < 8; i++)
KUNIT_EXPECT_EQ(test, buf[i], (char)'x');
test_free(buf);
KUNIT_EXPECT_FALSE(test, report_available());
}
/* Test that memory is zeroed if requested. */
static void test_gfpzero(struct kunit *test)
{
const size_t size = PAGE_SIZE; /* PAGE_SIZE so we can use ALLOCATE_ANY. */
char *buf1, *buf2;
int i;
/* Skip if we think it'd take too long. */
KFENCE_TEST_REQUIRES(test, kfence_sample_interval <= 100);
setup_test_cache(test, size, 0, NULL);
buf1 = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY);
for (i = 0; i < size; i++)
buf1[i] = i + 1;
test_free(buf1);
/* Try to get same address again -- this can take a while. */
for (i = 0;; i++) {
buf2 = test_alloc(test, size, GFP_KERNEL | __GFP_ZERO, ALLOCATE_ANY);
if (buf1 == buf2)
break;
test_free(buf2);
if (kthread_should_stop() || (i == CONFIG_KFENCE_NUM_OBJECTS)) {
kunit_warn(test, "giving up ... cannot get same object back\n");
return;
}
cond_resched();
}
for (i = 0; i < size; i++)
KUNIT_EXPECT_EQ(test, buf2[i], (char)0);
test_free(buf2);
KUNIT_EXPECT_FALSE(test, report_available());
}
static void test_invalid_access(struct kunit *test)
{
const struct expect_report expect = {
.type = KFENCE_ERROR_INVALID,
.fn = test_invalid_access,
.addr = &__kfence_pool[10],
.is_write = false,
};
READ_ONCE(__kfence_pool[10]);
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
}
/* Test SLAB_TYPESAFE_BY_RCU works. */
static void test_memcache_typesafe_by_rcu(struct kunit *test)
{
const size_t size = 32;
struct expect_report expect = {
.type = KFENCE_ERROR_UAF,
.fn = test_memcache_typesafe_by_rcu,
.is_write = false,
};
setup_test_cache(test, size, SLAB_TYPESAFE_BY_RCU, NULL);
KUNIT_EXPECT_TRUE(test, test_cache); /* Want memcache. */
expect.addr = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY);
*expect.addr = 42;
rcu_read_lock();
test_free(expect.addr);
KUNIT_EXPECT_EQ(test, *expect.addr, (char)42);
/*
* Up to this point, memory should not have been freed yet, and
* therefore there should be no KFENCE report from the above access.
*/
rcu_read_unlock();
/* Above access to @expect.addr should not have generated a report! */
KUNIT_EXPECT_FALSE(test, report_available());
/* Only after rcu_barrier() is the memory guaranteed to be freed. */
rcu_barrier();
/* Expect use-after-free. */
KUNIT_EXPECT_EQ(test, *expect.addr, (char)42);
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
}
/* Test krealloc(). */
static void test_krealloc(struct kunit *test)
{
const size_t size = 32;
const struct expect_report expect = {
.type = KFENCE_ERROR_UAF,
.fn = test_krealloc,
.addr = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY),
.is_write = false,
};
char *buf = expect.addr;
int i;
KUNIT_EXPECT_FALSE(test, test_cache);
KUNIT_EXPECT_EQ(test, ksize(buf), size); /* Precise size match after KFENCE alloc. */
for (i = 0; i < size; i++)
buf[i] = i + 1;
/* Check that we successfully change the size. */
buf = krealloc(buf, size * 3, GFP_KERNEL); /* Grow. */
/* Note: Might no longer be a KFENCE alloc. */
KUNIT_EXPECT_GE(test, ksize(buf), size * 3);
for (i = 0; i < size; i++)
KUNIT_EXPECT_EQ(test, buf[i], (char)(i + 1));
for (; i < size * 3; i++) /* Fill to extra bytes. */
buf[i] = i + 1;
buf = krealloc(buf, size * 2, GFP_KERNEL); /* Shrink. */
KUNIT_EXPECT_GE(test, ksize(buf), size * 2);
for (i = 0; i < size * 2; i++)
KUNIT_EXPECT_EQ(test, buf[i], (char)(i + 1));
buf = krealloc(buf, 0, GFP_KERNEL); /* Free. */
KUNIT_EXPECT_EQ(test, (unsigned long)buf, (unsigned long)ZERO_SIZE_PTR);
KUNIT_ASSERT_FALSE(test, report_available()); /* No reports yet! */
READ_ONCE(*expect.addr); /* Ensure krealloc() actually freed earlier KFENCE object. */
KUNIT_ASSERT_TRUE(test, report_matches(&expect));
}
/* Test that some objects from a bulk allocation belong to KFENCE pool. */
static void test_memcache_alloc_bulk(struct kunit *test)
{
const size_t size = 32;
bool pass = false;
unsigned long timeout;
setup_test_cache(test, size, 0, NULL);
KUNIT_EXPECT_TRUE(test, test_cache); /* Want memcache. */
/*
* 100x the sample interval should be more than enough to ensure we get
* a KFENCE allocation eventually.
*/
timeout = jiffies + msecs_to_jiffies(100 * kfence_sample_interval);
do {
void *objects[100];
int i, num = kmem_cache_alloc_bulk(test_cache, GFP_ATOMIC, ARRAY_SIZE(objects),
objects);
if (!num)
continue;
for (i = 0; i < ARRAY_SIZE(objects); i++) {
if (is_kfence_address(objects[i])) {
pass = true;
break;
}
}
kmem_cache_free_bulk(test_cache, num, objects);
/*
* kmem_cache_alloc_bulk() disables interrupts, and calling it
* in a tight loop may not give KFENCE a chance to switch the
* static branch. Call cond_resched() to let KFENCE chime in.
*/
cond_resched();
} while (!pass && time_before(jiffies, timeout));
KUNIT_EXPECT_TRUE(test, pass);
KUNIT_EXPECT_FALSE(test, report_available());
}
/*
* KUnit does not provide a way to provide arguments to tests, and we encode
* additional info in the name. Set up 2 tests per test case, one using the
* default allocator, and another using a custom memcache (suffix '-memcache').
*/
#define KFENCE_KUNIT_CASE(test_name) \
{ .run_case = test_name, .name = #test_name }, \
{ .run_case = test_name, .name = #test_name "-memcache" }
static struct kunit_case kfence_test_cases[] = {
KFENCE_KUNIT_CASE(test_out_of_bounds_read),
KFENCE_KUNIT_CASE(test_out_of_bounds_write),
KFENCE_KUNIT_CASE(test_use_after_free_read),
KFENCE_KUNIT_CASE(test_double_free),
KFENCE_KUNIT_CASE(test_invalid_addr_free),
KFENCE_KUNIT_CASE(test_corruption),
KFENCE_KUNIT_CASE(test_free_bulk),
KFENCE_KUNIT_CASE(test_init_on_free),
KUNIT_CASE(test_kmalloc_aligned_oob_read),
KUNIT_CASE(test_kmalloc_aligned_oob_write),
KUNIT_CASE(test_shrink_memcache),
KUNIT_CASE(test_memcache_ctor),
KUNIT_CASE(test_invalid_access),
KUNIT_CASE(test_gfpzero),
KUNIT_CASE(test_memcache_typesafe_by_rcu),
KUNIT_CASE(test_krealloc),
KUNIT_CASE(test_memcache_alloc_bulk),
{},
};
/* ===== End test cases ===== */
static int test_init(struct kunit *test)
{
unsigned long flags;
int i;
if (!__kfence_pool)
return -EINVAL;
spin_lock_irqsave(&observed.lock, flags);
for (i = 0; i < ARRAY_SIZE(observed.lines); i++)
observed.lines[i][0] = '\0';
observed.nlines = 0;
spin_unlock_irqrestore(&observed.lock, flags);
/* Any test with 'memcache' in its name will want a memcache. */
if (strstr(test->name, "memcache"))
test->priv = TEST_PRIV_WANT_MEMCACHE;
else
test->priv = NULL;
return 0;
}
static void test_exit(struct kunit *test)
{
test_cache_destroy();
}
static int kfence_suite_init(struct kunit_suite *suite)
{
register_trace_console(probe_console, NULL);
return 0;
}
static void kfence_suite_exit(struct kunit_suite *suite)
{
unregister_trace_console(probe_console, NULL);
tracepoint_synchronize_unregister();
}
static struct kunit_suite kfence_test_suite = {
.name = "kfence",
.test_cases = kfence_test_cases,
.init = test_init,
.exit = test_exit,
.suite_init = kfence_suite_init,
.suite_exit = kfence_suite_exit,
};
kunit_test_suites(&kfence_test_suite);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Alexander Potapenko <[email protected]>, Marco Elver <[email protected]>");
| linux-master | mm/kfence/kfence_test.c |
// SPDX-License-Identifier: GPL-2.0
/*
* KFENCE reporting.
*
* Copyright (C) 2020, Google LLC.
*/
#include <linux/stdarg.h>
#include <linux/kernel.h>
#include <linux/lockdep.h>
#include <linux/math.h>
#include <linux/printk.h>
#include <linux/sched/debug.h>
#include <linux/seq_file.h>
#include <linux/sprintf.h>
#include <linux/stacktrace.h>
#include <linux/string.h>
#include <trace/events/error_report.h>
#include <asm/kfence.h>
#include "kfence.h"
/* May be overridden by <asm/kfence.h>. */
#ifndef ARCH_FUNC_PREFIX
#define ARCH_FUNC_PREFIX ""
#endif
/* Helper function to either print to a seq_file or to console. */
__printf(2, 3)
static void seq_con_printf(struct seq_file *seq, const char *fmt, ...)
{
va_list args;
va_start(args, fmt);
if (seq)
seq_vprintf(seq, fmt, args);
else
vprintk(fmt, args);
va_end(args);
}
/*
* Get the number of stack entries to skip to get out of MM internals. @type is
* optional, and if set to NULL, assumes an allocation or free stack.
*/
static int get_stack_skipnr(const unsigned long stack_entries[], int num_entries,
const enum kfence_error_type *type)
{
char buf[64];
int skipnr, fallback = 0;
if (type) {
/* Depending on error type, find different stack entries. */
switch (*type) {
case KFENCE_ERROR_UAF:
case KFENCE_ERROR_OOB:
case KFENCE_ERROR_INVALID:
/*
* kfence_handle_page_fault() may be called with pt_regs
* set to NULL; in that case we'll simply show the full
* stack trace.
*/
return 0;
case KFENCE_ERROR_CORRUPTION:
case KFENCE_ERROR_INVALID_FREE:
break;
}
}
for (skipnr = 0; skipnr < num_entries; skipnr++) {
int len = scnprintf(buf, sizeof(buf), "%ps", (void *)stack_entries[skipnr]);
if (str_has_prefix(buf, ARCH_FUNC_PREFIX "kfence_") ||
str_has_prefix(buf, ARCH_FUNC_PREFIX "__kfence_") ||
str_has_prefix(buf, ARCH_FUNC_PREFIX "__kmem_cache_free") ||
!strncmp(buf, ARCH_FUNC_PREFIX "__slab_free", len)) {
/*
* In case of tail calls from any of the below to any of
* the above, optimized by the compiler such that the
* stack trace would omit the initial entry point below.
*/
fallback = skipnr + 1;
}
/*
* The below list should only include the initial entry points
* into the slab allocators. Includes the *_bulk() variants by
* checking prefixes.
*/
if (str_has_prefix(buf, ARCH_FUNC_PREFIX "kfree") ||
str_has_prefix(buf, ARCH_FUNC_PREFIX "kmem_cache_free") ||
str_has_prefix(buf, ARCH_FUNC_PREFIX "__kmalloc") ||
str_has_prefix(buf, ARCH_FUNC_PREFIX "kmem_cache_alloc"))
goto found;
}
if (fallback < num_entries)
return fallback;
found:
skipnr++;
return skipnr < num_entries ? skipnr : 0;
}
static void kfence_print_stack(struct seq_file *seq, const struct kfence_metadata *meta,
bool show_alloc)
{
const struct kfence_track *track = show_alloc ? &meta->alloc_track : &meta->free_track;
u64 ts_sec = track->ts_nsec;
unsigned long rem_nsec = do_div(ts_sec, NSEC_PER_SEC);
/* Timestamp matches printk timestamp format. */
seq_con_printf(seq, "%s by task %d on cpu %d at %lu.%06lus:\n",
show_alloc ? "allocated" : "freed", track->pid,
track->cpu, (unsigned long)ts_sec, rem_nsec / 1000);
if (track->num_stack_entries) {
/* Skip allocation/free internals stack. */
int i = get_stack_skipnr(track->stack_entries, track->num_stack_entries, NULL);
/* stack_trace_seq_print() does not exist; open code our own. */
for (; i < track->num_stack_entries; i++)
seq_con_printf(seq, " %pS\n", (void *)track->stack_entries[i]);
} else {
seq_con_printf(seq, " no %s stack\n", show_alloc ? "allocation" : "deallocation");
}
}
void kfence_print_object(struct seq_file *seq, const struct kfence_metadata *meta)
{
const int size = abs(meta->size);
const unsigned long start = meta->addr;
const struct kmem_cache *const cache = meta->cache;
lockdep_assert_held(&meta->lock);
if (meta->state == KFENCE_OBJECT_UNUSED) {
seq_con_printf(seq, "kfence-#%td unused\n", meta - kfence_metadata);
return;
}
seq_con_printf(seq, "kfence-#%td: 0x%p-0x%p, size=%d, cache=%s\n\n",
meta - kfence_metadata, (void *)start, (void *)(start + size - 1),
size, (cache && cache->name) ? cache->name : "<destroyed>");
kfence_print_stack(seq, meta, true);
if (meta->state == KFENCE_OBJECT_FREED) {
seq_con_printf(seq, "\n");
kfence_print_stack(seq, meta, false);
}
}
/*
* Show bytes at @addr that are different from the expected canary values, up to
* @max_bytes.
*/
static void print_diff_canary(unsigned long address, size_t bytes_to_show,
const struct kfence_metadata *meta)
{
const unsigned long show_until_addr = address + bytes_to_show;
const u8 *cur, *end;
/* Do not show contents of object nor read into following guard page. */
end = (const u8 *)(address < meta->addr ? min(show_until_addr, meta->addr)
: min(show_until_addr, PAGE_ALIGN(address)));
pr_cont("[");
for (cur = (const u8 *)address; cur < end; cur++) {
if (*cur == KFENCE_CANARY_PATTERN_U8(cur))
pr_cont(" .");
else if (no_hash_pointers)
pr_cont(" 0x%02x", *cur);
else /* Do not leak kernel memory in non-debug builds. */
pr_cont(" !");
}
pr_cont(" ]");
}
static const char *get_access_type(bool is_write)
{
return is_write ? "write" : "read";
}
void kfence_report_error(unsigned long address, bool is_write, struct pt_regs *regs,
const struct kfence_metadata *meta, enum kfence_error_type type)
{
unsigned long stack_entries[KFENCE_STACK_DEPTH] = { 0 };
const ptrdiff_t object_index = meta ? meta - kfence_metadata : -1;
int num_stack_entries;
int skipnr = 0;
if (regs) {
num_stack_entries = stack_trace_save_regs(regs, stack_entries, KFENCE_STACK_DEPTH, 0);
} else {
num_stack_entries = stack_trace_save(stack_entries, KFENCE_STACK_DEPTH, 1);
skipnr = get_stack_skipnr(stack_entries, num_stack_entries, &type);
}
/* Require non-NULL meta, except if KFENCE_ERROR_INVALID. */
if (WARN_ON(type != KFENCE_ERROR_INVALID && !meta))
return;
if (meta)
lockdep_assert_held(&meta->lock);
/*
* Because we may generate reports in printk-unfriendly parts of the
* kernel, such as scheduler code, the use of printk() could deadlock.
* Until such time that all printing code here is safe in all parts of
* the kernel, accept the risk, and just get our message out (given the
* system might already behave unpredictably due to the memory error).
* As such, also disable lockdep to hide warnings, and avoid disabling
* lockdep for the rest of the kernel.
*/
lockdep_off();
pr_err("==================================================================\n");
/* Print report header. */
switch (type) {
case KFENCE_ERROR_OOB: {
const bool left_of_object = address < meta->addr;
pr_err("BUG: KFENCE: out-of-bounds %s in %pS\n\n", get_access_type(is_write),
(void *)stack_entries[skipnr]);
pr_err("Out-of-bounds %s at 0x%p (%luB %s of kfence-#%td):\n",
get_access_type(is_write), (void *)address,
left_of_object ? meta->addr - address : address - meta->addr,
left_of_object ? "left" : "right", object_index);
break;
}
case KFENCE_ERROR_UAF:
pr_err("BUG: KFENCE: use-after-free %s in %pS\n\n", get_access_type(is_write),
(void *)stack_entries[skipnr]);
pr_err("Use-after-free %s at 0x%p (in kfence-#%td):\n",
get_access_type(is_write), (void *)address, object_index);
break;
case KFENCE_ERROR_CORRUPTION:
pr_err("BUG: KFENCE: memory corruption in %pS\n\n", (void *)stack_entries[skipnr]);
pr_err("Corrupted memory at 0x%p ", (void *)address);
print_diff_canary(address, 16, meta);
pr_cont(" (in kfence-#%td):\n", object_index);
break;
case KFENCE_ERROR_INVALID:
pr_err("BUG: KFENCE: invalid %s in %pS\n\n", get_access_type(is_write),
(void *)stack_entries[skipnr]);
pr_err("Invalid %s at 0x%p:\n", get_access_type(is_write),
(void *)address);
break;
case KFENCE_ERROR_INVALID_FREE:
pr_err("BUG: KFENCE: invalid free in %pS\n\n", (void *)stack_entries[skipnr]);
pr_err("Invalid free of 0x%p (in kfence-#%td):\n", (void *)address,
object_index);
break;
}
/* Print stack trace and object info. */
stack_trace_print(stack_entries + skipnr, num_stack_entries - skipnr, 0);
if (meta) {
pr_err("\n");
kfence_print_object(NULL, meta);
}
/* Print report footer. */
pr_err("\n");
if (no_hash_pointers && regs)
show_regs(regs);
else
dump_stack_print_info(KERN_ERR);
trace_error_report_end(ERROR_DETECTOR_KFENCE, address);
pr_err("==================================================================\n");
lockdep_on();
check_panic_on_warn("KFENCE");
/* We encountered a memory safety error, taint the kernel! */
add_taint(TAINT_BAD_PAGE, LOCKDEP_STILL_OK);
}
#ifdef CONFIG_PRINTK
static void kfence_to_kp_stack(const struct kfence_track *track, void **kp_stack)
{
int i, j;
i = get_stack_skipnr(track->stack_entries, track->num_stack_entries, NULL);
for (j = 0; i < track->num_stack_entries && j < KS_ADDRS_COUNT; ++i, ++j)
kp_stack[j] = (void *)track->stack_entries[i];
if (j < KS_ADDRS_COUNT)
kp_stack[j] = NULL;
}
bool __kfence_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab)
{
struct kfence_metadata *meta = addr_to_metadata((unsigned long)object);
unsigned long flags;
if (!meta)
return false;
/*
* If state is UNUSED at least show the pointer requested; the rest
* would be garbage data.
*/
kpp->kp_ptr = object;
/* Requesting info an a never-used object is almost certainly a bug. */
if (WARN_ON(meta->state == KFENCE_OBJECT_UNUSED))
return true;
raw_spin_lock_irqsave(&meta->lock, flags);
kpp->kp_slab = slab;
kpp->kp_slab_cache = meta->cache;
kpp->kp_objp = (void *)meta->addr;
kfence_to_kp_stack(&meta->alloc_track, kpp->kp_stack);
if (meta->state == KFENCE_OBJECT_FREED)
kfence_to_kp_stack(&meta->free_track, kpp->kp_free_stack);
/* get_stack_skipnr() ensures the first entry is outside allocator. */
kpp->kp_ret = kpp->kp_stack[0];
raw_spin_unlock_irqrestore(&meta->lock, flags);
return true;
}
#endif
| linux-master | mm/kfence/report.c |
// SPDX-License-Identifier: GPL-2.0
/*
* KFENCE guarded object allocator and fault handling.
*
* Copyright (C) 2020, Google LLC.
*/
#define pr_fmt(fmt) "kfence: " fmt
#include <linux/atomic.h>
#include <linux/bug.h>
#include <linux/debugfs.h>
#include <linux/hash.h>
#include <linux/irq_work.h>
#include <linux/jhash.h>
#include <linux/kcsan-checks.h>
#include <linux/kfence.h>
#include <linux/kmemleak.h>
#include <linux/list.h>
#include <linux/lockdep.h>
#include <linux/log2.h>
#include <linux/memblock.h>
#include <linux/moduleparam.h>
#include <linux/notifier.h>
#include <linux/panic_notifier.h>
#include <linux/random.h>
#include <linux/rcupdate.h>
#include <linux/sched/clock.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <asm/kfence.h>
#include "kfence.h"
/* Disables KFENCE on the first warning assuming an irrecoverable error. */
#define KFENCE_WARN_ON(cond) \
({ \
const bool __cond = WARN_ON(cond); \
if (unlikely(__cond)) { \
WRITE_ONCE(kfence_enabled, false); \
disabled_by_warn = true; \
} \
__cond; \
})
/* === Data ================================================================= */
static bool kfence_enabled __read_mostly;
static bool disabled_by_warn __read_mostly;
unsigned long kfence_sample_interval __read_mostly = CONFIG_KFENCE_SAMPLE_INTERVAL;
EXPORT_SYMBOL_GPL(kfence_sample_interval); /* Export for test modules. */
#ifdef MODULE_PARAM_PREFIX
#undef MODULE_PARAM_PREFIX
#endif
#define MODULE_PARAM_PREFIX "kfence."
static int kfence_enable_late(void);
static int param_set_sample_interval(const char *val, const struct kernel_param *kp)
{
unsigned long num;
int ret = kstrtoul(val, 0, &num);
if (ret < 0)
return ret;
/* Using 0 to indicate KFENCE is disabled. */
if (!num && READ_ONCE(kfence_enabled)) {
pr_info("disabled\n");
WRITE_ONCE(kfence_enabled, false);
}
*((unsigned long *)kp->arg) = num;
if (num && !READ_ONCE(kfence_enabled) && system_state != SYSTEM_BOOTING)
return disabled_by_warn ? -EINVAL : kfence_enable_late();
return 0;
}
static int param_get_sample_interval(char *buffer, const struct kernel_param *kp)
{
if (!READ_ONCE(kfence_enabled))
return sprintf(buffer, "0\n");
return param_get_ulong(buffer, kp);
}
static const struct kernel_param_ops sample_interval_param_ops = {
.set = param_set_sample_interval,
.get = param_get_sample_interval,
};
module_param_cb(sample_interval, &sample_interval_param_ops, &kfence_sample_interval, 0600);
/* Pool usage% threshold when currently covered allocations are skipped. */
static unsigned long kfence_skip_covered_thresh __read_mostly = 75;
module_param_named(skip_covered_thresh, kfence_skip_covered_thresh, ulong, 0644);
/* If true, use a deferrable timer. */
static bool kfence_deferrable __read_mostly = IS_ENABLED(CONFIG_KFENCE_DEFERRABLE);
module_param_named(deferrable, kfence_deferrable, bool, 0444);
/* If true, check all canary bytes on panic. */
static bool kfence_check_on_panic __read_mostly;
module_param_named(check_on_panic, kfence_check_on_panic, bool, 0444);
/* The pool of pages used for guard pages and objects. */
char *__kfence_pool __read_mostly;
EXPORT_SYMBOL(__kfence_pool); /* Export for test modules. */
/*
* Per-object metadata, with one-to-one mapping of object metadata to
* backing pages (in __kfence_pool).
*/
static_assert(CONFIG_KFENCE_NUM_OBJECTS > 0);
struct kfence_metadata *kfence_metadata __read_mostly;
/*
* If kfence_metadata is not NULL, it may be accessed by kfence_shutdown_cache().
* So introduce kfence_metadata_init to initialize metadata, and then make
* kfence_metadata visible after initialization is successful. This prevents
* potential UAF or access to uninitialized metadata.
*/
static struct kfence_metadata *kfence_metadata_init __read_mostly;
/* Freelist with available objects. */
static struct list_head kfence_freelist = LIST_HEAD_INIT(kfence_freelist);
static DEFINE_RAW_SPINLOCK(kfence_freelist_lock); /* Lock protecting freelist. */
/*
* The static key to set up a KFENCE allocation; or if static keys are not used
* to gate allocations, to avoid a load and compare if KFENCE is disabled.
*/
DEFINE_STATIC_KEY_FALSE(kfence_allocation_key);
/* Gates the allocation, ensuring only one succeeds in a given period. */
atomic_t kfence_allocation_gate = ATOMIC_INIT(1);
/*
* A Counting Bloom filter of allocation coverage: limits currently covered
* allocations of the same source filling up the pool.
*
* Assuming a range of 15%-85% unique allocations in the pool at any point in
* time, the below parameters provide a probablity of 0.02-0.33 for false
* positive hits respectively:
*
* P(alloc_traces) = (1 - e^(-HNUM * (alloc_traces / SIZE)) ^ HNUM
*/
#define ALLOC_COVERED_HNUM 2
#define ALLOC_COVERED_ORDER (const_ilog2(CONFIG_KFENCE_NUM_OBJECTS) + 2)
#define ALLOC_COVERED_SIZE (1 << ALLOC_COVERED_ORDER)
#define ALLOC_COVERED_HNEXT(h) hash_32(h, ALLOC_COVERED_ORDER)
#define ALLOC_COVERED_MASK (ALLOC_COVERED_SIZE - 1)
static atomic_t alloc_covered[ALLOC_COVERED_SIZE];
/* Stack depth used to determine uniqueness of an allocation. */
#define UNIQUE_ALLOC_STACK_DEPTH ((size_t)8)
/*
* Randomness for stack hashes, making the same collisions across reboots and
* different machines less likely.
*/
static u32 stack_hash_seed __ro_after_init;
/* Statistics counters for debugfs. */
enum kfence_counter_id {
KFENCE_COUNTER_ALLOCATED,
KFENCE_COUNTER_ALLOCS,
KFENCE_COUNTER_FREES,
KFENCE_COUNTER_ZOMBIES,
KFENCE_COUNTER_BUGS,
KFENCE_COUNTER_SKIP_INCOMPAT,
KFENCE_COUNTER_SKIP_CAPACITY,
KFENCE_COUNTER_SKIP_COVERED,
KFENCE_COUNTER_COUNT,
};
static atomic_long_t counters[KFENCE_COUNTER_COUNT];
static const char *const counter_names[] = {
[KFENCE_COUNTER_ALLOCATED] = "currently allocated",
[KFENCE_COUNTER_ALLOCS] = "total allocations",
[KFENCE_COUNTER_FREES] = "total frees",
[KFENCE_COUNTER_ZOMBIES] = "zombie allocations",
[KFENCE_COUNTER_BUGS] = "total bugs",
[KFENCE_COUNTER_SKIP_INCOMPAT] = "skipped allocations (incompatible)",
[KFENCE_COUNTER_SKIP_CAPACITY] = "skipped allocations (capacity)",
[KFENCE_COUNTER_SKIP_COVERED] = "skipped allocations (covered)",
};
static_assert(ARRAY_SIZE(counter_names) == KFENCE_COUNTER_COUNT);
/* === Internals ============================================================ */
static inline bool should_skip_covered(void)
{
unsigned long thresh = (CONFIG_KFENCE_NUM_OBJECTS * kfence_skip_covered_thresh) / 100;
return atomic_long_read(&counters[KFENCE_COUNTER_ALLOCATED]) > thresh;
}
static u32 get_alloc_stack_hash(unsigned long *stack_entries, size_t num_entries)
{
num_entries = min(num_entries, UNIQUE_ALLOC_STACK_DEPTH);
num_entries = filter_irq_stacks(stack_entries, num_entries);
return jhash(stack_entries, num_entries * sizeof(stack_entries[0]), stack_hash_seed);
}
/*
* Adds (or subtracts) count @val for allocation stack trace hash
* @alloc_stack_hash from Counting Bloom filter.
*/
static void alloc_covered_add(u32 alloc_stack_hash, int val)
{
int i;
for (i = 0; i < ALLOC_COVERED_HNUM; i++) {
atomic_add(val, &alloc_covered[alloc_stack_hash & ALLOC_COVERED_MASK]);
alloc_stack_hash = ALLOC_COVERED_HNEXT(alloc_stack_hash);
}
}
/*
* Returns true if the allocation stack trace hash @alloc_stack_hash is
* currently contained (non-zero count) in Counting Bloom filter.
*/
static bool alloc_covered_contains(u32 alloc_stack_hash)
{
int i;
for (i = 0; i < ALLOC_COVERED_HNUM; i++) {
if (!atomic_read(&alloc_covered[alloc_stack_hash & ALLOC_COVERED_MASK]))
return false;
alloc_stack_hash = ALLOC_COVERED_HNEXT(alloc_stack_hash);
}
return true;
}
static bool kfence_protect(unsigned long addr)
{
return !KFENCE_WARN_ON(!kfence_protect_page(ALIGN_DOWN(addr, PAGE_SIZE), true));
}
static bool kfence_unprotect(unsigned long addr)
{
return !KFENCE_WARN_ON(!kfence_protect_page(ALIGN_DOWN(addr, PAGE_SIZE), false));
}
static inline unsigned long metadata_to_pageaddr(const struct kfence_metadata *meta)
{
unsigned long offset = (meta - kfence_metadata + 1) * PAGE_SIZE * 2;
unsigned long pageaddr = (unsigned long)&__kfence_pool[offset];
/* The checks do not affect performance; only called from slow-paths. */
/* Only call with a pointer into kfence_metadata. */
if (KFENCE_WARN_ON(meta < kfence_metadata ||
meta >= kfence_metadata + CONFIG_KFENCE_NUM_OBJECTS))
return 0;
/*
* This metadata object only ever maps to 1 page; verify that the stored
* address is in the expected range.
*/
if (KFENCE_WARN_ON(ALIGN_DOWN(meta->addr, PAGE_SIZE) != pageaddr))
return 0;
return pageaddr;
}
/*
* Update the object's metadata state, including updating the alloc/free stacks
* depending on the state transition.
*/
static noinline void
metadata_update_state(struct kfence_metadata *meta, enum kfence_object_state next,
unsigned long *stack_entries, size_t num_stack_entries)
{
struct kfence_track *track =
next == KFENCE_OBJECT_FREED ? &meta->free_track : &meta->alloc_track;
lockdep_assert_held(&meta->lock);
if (stack_entries) {
memcpy(track->stack_entries, stack_entries,
num_stack_entries * sizeof(stack_entries[0]));
} else {
/*
* Skip over 1 (this) functions; noinline ensures we do not
* accidentally skip over the caller by never inlining.
*/
num_stack_entries = stack_trace_save(track->stack_entries, KFENCE_STACK_DEPTH, 1);
}
track->num_stack_entries = num_stack_entries;
track->pid = task_pid_nr(current);
track->cpu = raw_smp_processor_id();
track->ts_nsec = local_clock(); /* Same source as printk timestamps. */
/*
* Pairs with READ_ONCE() in
* kfence_shutdown_cache(),
* kfence_handle_page_fault().
*/
WRITE_ONCE(meta->state, next);
}
/* Check canary byte at @addr. */
static inline bool check_canary_byte(u8 *addr)
{
struct kfence_metadata *meta;
unsigned long flags;
if (likely(*addr == KFENCE_CANARY_PATTERN_U8(addr)))
return true;
atomic_long_inc(&counters[KFENCE_COUNTER_BUGS]);
meta = addr_to_metadata((unsigned long)addr);
raw_spin_lock_irqsave(&meta->lock, flags);
kfence_report_error((unsigned long)addr, false, NULL, meta, KFENCE_ERROR_CORRUPTION);
raw_spin_unlock_irqrestore(&meta->lock, flags);
return false;
}
static inline void set_canary(const struct kfence_metadata *meta)
{
const unsigned long pageaddr = ALIGN_DOWN(meta->addr, PAGE_SIZE);
unsigned long addr = pageaddr;
/*
* The canary may be written to part of the object memory, but it does
* not affect it. The user should initialize the object before using it.
*/
for (; addr < meta->addr; addr += sizeof(u64))
*((u64 *)addr) = KFENCE_CANARY_PATTERN_U64;
addr = ALIGN_DOWN(meta->addr + meta->size, sizeof(u64));
for (; addr - pageaddr < PAGE_SIZE; addr += sizeof(u64))
*((u64 *)addr) = KFENCE_CANARY_PATTERN_U64;
}
static inline void check_canary(const struct kfence_metadata *meta)
{
const unsigned long pageaddr = ALIGN_DOWN(meta->addr, PAGE_SIZE);
unsigned long addr = pageaddr;
/*
* We'll iterate over each canary byte per-side until a corrupted byte
* is found. However, we'll still iterate over the canary bytes to the
* right of the object even if there was an error in the canary bytes to
* the left of the object. Specifically, if check_canary_byte()
* generates an error, showing both sides might give more clues as to
* what the error is about when displaying which bytes were corrupted.
*/
/* Apply to left of object. */
for (; meta->addr - addr >= sizeof(u64); addr += sizeof(u64)) {
if (unlikely(*((u64 *)addr) != KFENCE_CANARY_PATTERN_U64))
break;
}
/*
* If the canary is corrupted in a certain 64 bytes, or the canary
* memory cannot be completely covered by multiple consecutive 64 bytes,
* it needs to be checked one by one.
*/
for (; addr < meta->addr; addr++) {
if (unlikely(!check_canary_byte((u8 *)addr)))
break;
}
/* Apply to right of object. */
for (addr = meta->addr + meta->size; addr % sizeof(u64) != 0; addr++) {
if (unlikely(!check_canary_byte((u8 *)addr)))
return;
}
for (; addr - pageaddr < PAGE_SIZE; addr += sizeof(u64)) {
if (unlikely(*((u64 *)addr) != KFENCE_CANARY_PATTERN_U64)) {
for (; addr - pageaddr < PAGE_SIZE; addr++) {
if (!check_canary_byte((u8 *)addr))
return;
}
}
}
}
static void *kfence_guarded_alloc(struct kmem_cache *cache, size_t size, gfp_t gfp,
unsigned long *stack_entries, size_t num_stack_entries,
u32 alloc_stack_hash)
{
struct kfence_metadata *meta = NULL;
unsigned long flags;
struct slab *slab;
void *addr;
const bool random_right_allocate = get_random_u32_below(2);
const bool random_fault = CONFIG_KFENCE_STRESS_TEST_FAULTS &&
!get_random_u32_below(CONFIG_KFENCE_STRESS_TEST_FAULTS);
/* Try to obtain a free object. */
raw_spin_lock_irqsave(&kfence_freelist_lock, flags);
if (!list_empty(&kfence_freelist)) {
meta = list_entry(kfence_freelist.next, struct kfence_metadata, list);
list_del_init(&meta->list);
}
raw_spin_unlock_irqrestore(&kfence_freelist_lock, flags);
if (!meta) {
atomic_long_inc(&counters[KFENCE_COUNTER_SKIP_CAPACITY]);
return NULL;
}
if (unlikely(!raw_spin_trylock_irqsave(&meta->lock, flags))) {
/*
* This is extremely unlikely -- we are reporting on a
* use-after-free, which locked meta->lock, and the reporting
* code via printk calls kmalloc() which ends up in
* kfence_alloc() and tries to grab the same object that we're
* reporting on. While it has never been observed, lockdep does
* report that there is a possibility of deadlock. Fix it by
* using trylock and bailing out gracefully.
*/
raw_spin_lock_irqsave(&kfence_freelist_lock, flags);
/* Put the object back on the freelist. */
list_add_tail(&meta->list, &kfence_freelist);
raw_spin_unlock_irqrestore(&kfence_freelist_lock, flags);
return NULL;
}
meta->addr = metadata_to_pageaddr(meta);
/* Unprotect if we're reusing this page. */
if (meta->state == KFENCE_OBJECT_FREED)
kfence_unprotect(meta->addr);
/*
* Note: for allocations made before RNG initialization, will always
* return zero. We still benefit from enabling KFENCE as early as
* possible, even when the RNG is not yet available, as this will allow
* KFENCE to detect bugs due to earlier allocations. The only downside
* is that the out-of-bounds accesses detected are deterministic for
* such allocations.
*/
if (random_right_allocate) {
/* Allocate on the "right" side, re-calculate address. */
meta->addr += PAGE_SIZE - size;
meta->addr = ALIGN_DOWN(meta->addr, cache->align);
}
addr = (void *)meta->addr;
/* Update remaining metadata. */
metadata_update_state(meta, KFENCE_OBJECT_ALLOCATED, stack_entries, num_stack_entries);
/* Pairs with READ_ONCE() in kfence_shutdown_cache(). */
WRITE_ONCE(meta->cache, cache);
meta->size = size;
meta->alloc_stack_hash = alloc_stack_hash;
raw_spin_unlock_irqrestore(&meta->lock, flags);
alloc_covered_add(alloc_stack_hash, 1);
/* Set required slab fields. */
slab = virt_to_slab((void *)meta->addr);
slab->slab_cache = cache;
#if defined(CONFIG_SLUB)
slab->objects = 1;
#elif defined(CONFIG_SLAB)
slab->s_mem = addr;
#endif
/* Memory initialization. */
set_canary(meta);
/*
* We check slab_want_init_on_alloc() ourselves, rather than letting
* SL*B do the initialization, as otherwise we might overwrite KFENCE's
* redzone.
*/
if (unlikely(slab_want_init_on_alloc(gfp, cache)))
memzero_explicit(addr, size);
if (cache->ctor)
cache->ctor(addr);
if (random_fault)
kfence_protect(meta->addr); /* Random "faults" by protecting the object. */
atomic_long_inc(&counters[KFENCE_COUNTER_ALLOCATED]);
atomic_long_inc(&counters[KFENCE_COUNTER_ALLOCS]);
return addr;
}
static void kfence_guarded_free(void *addr, struct kfence_metadata *meta, bool zombie)
{
struct kcsan_scoped_access assert_page_exclusive;
unsigned long flags;
bool init;
raw_spin_lock_irqsave(&meta->lock, flags);
if (meta->state != KFENCE_OBJECT_ALLOCATED || meta->addr != (unsigned long)addr) {
/* Invalid or double-free, bail out. */
atomic_long_inc(&counters[KFENCE_COUNTER_BUGS]);
kfence_report_error((unsigned long)addr, false, NULL, meta,
KFENCE_ERROR_INVALID_FREE);
raw_spin_unlock_irqrestore(&meta->lock, flags);
return;
}
/* Detect racy use-after-free, or incorrect reallocation of this page by KFENCE. */
kcsan_begin_scoped_access((void *)ALIGN_DOWN((unsigned long)addr, PAGE_SIZE), PAGE_SIZE,
KCSAN_ACCESS_SCOPED | KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ASSERT,
&assert_page_exclusive);
if (CONFIG_KFENCE_STRESS_TEST_FAULTS)
kfence_unprotect((unsigned long)addr); /* To check canary bytes. */
/* Restore page protection if there was an OOB access. */
if (meta->unprotected_page) {
memzero_explicit((void *)ALIGN_DOWN(meta->unprotected_page, PAGE_SIZE), PAGE_SIZE);
kfence_protect(meta->unprotected_page);
meta->unprotected_page = 0;
}
/* Mark the object as freed. */
metadata_update_state(meta, KFENCE_OBJECT_FREED, NULL, 0);
init = slab_want_init_on_free(meta->cache);
raw_spin_unlock_irqrestore(&meta->lock, flags);
alloc_covered_add(meta->alloc_stack_hash, -1);
/* Check canary bytes for memory corruption. */
check_canary(meta);
/*
* Clear memory if init-on-free is set. While we protect the page, the
* data is still there, and after a use-after-free is detected, we
* unprotect the page, so the data is still accessible.
*/
if (!zombie && unlikely(init))
memzero_explicit(addr, meta->size);
/* Protect to detect use-after-frees. */
kfence_protect((unsigned long)addr);
kcsan_end_scoped_access(&assert_page_exclusive);
if (!zombie) {
/* Add it to the tail of the freelist for reuse. */
raw_spin_lock_irqsave(&kfence_freelist_lock, flags);
KFENCE_WARN_ON(!list_empty(&meta->list));
list_add_tail(&meta->list, &kfence_freelist);
raw_spin_unlock_irqrestore(&kfence_freelist_lock, flags);
atomic_long_dec(&counters[KFENCE_COUNTER_ALLOCATED]);
atomic_long_inc(&counters[KFENCE_COUNTER_FREES]);
} else {
/* See kfence_shutdown_cache(). */
atomic_long_inc(&counters[KFENCE_COUNTER_ZOMBIES]);
}
}
static void rcu_guarded_free(struct rcu_head *h)
{
struct kfence_metadata *meta = container_of(h, struct kfence_metadata, rcu_head);
kfence_guarded_free((void *)meta->addr, meta, false);
}
/*
* Initialization of the KFENCE pool after its allocation.
* Returns 0 on success; otherwise returns the address up to
* which partial initialization succeeded.
*/
static unsigned long kfence_init_pool(void)
{
unsigned long addr;
struct page *pages;
int i;
if (!arch_kfence_init_pool())
return (unsigned long)__kfence_pool;
addr = (unsigned long)__kfence_pool;
pages = virt_to_page(__kfence_pool);
/*
* Set up object pages: they must have PG_slab set, to avoid freeing
* these as real pages.
*
* We also want to avoid inserting kfence_free() in the kfree()
* fast-path in SLUB, and therefore need to ensure kfree() correctly
* enters __slab_free() slow-path.
*/
for (i = 0; i < KFENCE_POOL_SIZE / PAGE_SIZE; i++) {
struct slab *slab = page_slab(nth_page(pages, i));
if (!i || (i % 2))
continue;
__folio_set_slab(slab_folio(slab));
#ifdef CONFIG_MEMCG
slab->memcg_data = (unsigned long)&kfence_metadata_init[i / 2 - 1].objcg |
MEMCG_DATA_OBJCGS;
#endif
}
/*
* Protect the first 2 pages. The first page is mostly unnecessary, and
* merely serves as an extended guard page. However, adding one
* additional page in the beginning gives us an even number of pages,
* which simplifies the mapping of address to metadata index.
*/
for (i = 0; i < 2; i++) {
if (unlikely(!kfence_protect(addr)))
return addr;
addr += PAGE_SIZE;
}
for (i = 0; i < CONFIG_KFENCE_NUM_OBJECTS; i++) {
struct kfence_metadata *meta = &kfence_metadata_init[i];
/* Initialize metadata. */
INIT_LIST_HEAD(&meta->list);
raw_spin_lock_init(&meta->lock);
meta->state = KFENCE_OBJECT_UNUSED;
meta->addr = addr; /* Initialize for validation in metadata_to_pageaddr(). */
list_add_tail(&meta->list, &kfence_freelist);
/* Protect the right redzone. */
if (unlikely(!kfence_protect(addr + PAGE_SIZE)))
goto reset_slab;
addr += 2 * PAGE_SIZE;
}
/*
* Make kfence_metadata visible only when initialization is successful.
* Otherwise, if the initialization fails and kfence_metadata is freed,
* it may cause UAF in kfence_shutdown_cache().
*/
smp_store_release(&kfence_metadata, kfence_metadata_init);
return 0;
reset_slab:
for (i = 0; i < KFENCE_POOL_SIZE / PAGE_SIZE; i++) {
struct slab *slab = page_slab(nth_page(pages, i));
if (!i || (i % 2))
continue;
#ifdef CONFIG_MEMCG
slab->memcg_data = 0;
#endif
__folio_clear_slab(slab_folio(slab));
}
return addr;
}
static bool __init kfence_init_pool_early(void)
{
unsigned long addr;
if (!__kfence_pool)
return false;
addr = kfence_init_pool();
if (!addr) {
/*
* The pool is live and will never be deallocated from this point on.
* Ignore the pool object from the kmemleak phys object tree, as it would
* otherwise overlap with allocations returned by kfence_alloc(), which
* are registered with kmemleak through the slab post-alloc hook.
*/
kmemleak_ignore_phys(__pa(__kfence_pool));
return true;
}
/*
* Only release unprotected pages, and do not try to go back and change
* page attributes due to risk of failing to do so as well. If changing
* page attributes for some pages fails, it is very likely that it also
* fails for the first page, and therefore expect addr==__kfence_pool in
* most failure cases.
*/
memblock_free_late(__pa(addr), KFENCE_POOL_SIZE - (addr - (unsigned long)__kfence_pool));
__kfence_pool = NULL;
memblock_free_late(__pa(kfence_metadata_init), KFENCE_METADATA_SIZE);
kfence_metadata_init = NULL;
return false;
}
/* === DebugFS Interface ==================================================== */
static int stats_show(struct seq_file *seq, void *v)
{
int i;
seq_printf(seq, "enabled: %i\n", READ_ONCE(kfence_enabled));
for (i = 0; i < KFENCE_COUNTER_COUNT; i++)
seq_printf(seq, "%s: %ld\n", counter_names[i], atomic_long_read(&counters[i]));
return 0;
}
DEFINE_SHOW_ATTRIBUTE(stats);
/*
* debugfs seq_file operations for /sys/kernel/debug/kfence/objects.
* start_object() and next_object() return the object index + 1, because NULL is used
* to stop iteration.
*/
static void *start_object(struct seq_file *seq, loff_t *pos)
{
if (*pos < CONFIG_KFENCE_NUM_OBJECTS)
return (void *)((long)*pos + 1);
return NULL;
}
static void stop_object(struct seq_file *seq, void *v)
{
}
static void *next_object(struct seq_file *seq, void *v, loff_t *pos)
{
++*pos;
if (*pos < CONFIG_KFENCE_NUM_OBJECTS)
return (void *)((long)*pos + 1);
return NULL;
}
static int show_object(struct seq_file *seq, void *v)
{
struct kfence_metadata *meta = &kfence_metadata[(long)v - 1];
unsigned long flags;
raw_spin_lock_irqsave(&meta->lock, flags);
kfence_print_object(seq, meta);
raw_spin_unlock_irqrestore(&meta->lock, flags);
seq_puts(seq, "---------------------------------\n");
return 0;
}
static const struct seq_operations objects_sops = {
.start = start_object,
.next = next_object,
.stop = stop_object,
.show = show_object,
};
DEFINE_SEQ_ATTRIBUTE(objects);
static int kfence_debugfs_init(void)
{
struct dentry *kfence_dir;
if (!READ_ONCE(kfence_enabled))
return 0;
kfence_dir = debugfs_create_dir("kfence", NULL);
debugfs_create_file("stats", 0444, kfence_dir, NULL, &stats_fops);
debugfs_create_file("objects", 0400, kfence_dir, NULL, &objects_fops);
return 0;
}
late_initcall(kfence_debugfs_init);
/* === Panic Notifier ====================================================== */
static void kfence_check_all_canary(void)
{
int i;
for (i = 0; i < CONFIG_KFENCE_NUM_OBJECTS; i++) {
struct kfence_metadata *meta = &kfence_metadata[i];
if (meta->state == KFENCE_OBJECT_ALLOCATED)
check_canary(meta);
}
}
static int kfence_check_canary_callback(struct notifier_block *nb,
unsigned long reason, void *arg)
{
kfence_check_all_canary();
return NOTIFY_OK;
}
static struct notifier_block kfence_check_canary_notifier = {
.notifier_call = kfence_check_canary_callback,
};
/* === Allocation Gate Timer ================================================ */
static struct delayed_work kfence_timer;
#ifdef CONFIG_KFENCE_STATIC_KEYS
/* Wait queue to wake up allocation-gate timer task. */
static DECLARE_WAIT_QUEUE_HEAD(allocation_wait);
static void wake_up_kfence_timer(struct irq_work *work)
{
wake_up(&allocation_wait);
}
static DEFINE_IRQ_WORK(wake_up_kfence_timer_work, wake_up_kfence_timer);
#endif
/*
* Set up delayed work, which will enable and disable the static key. We need to
* use a work queue (rather than a simple timer), since enabling and disabling a
* static key cannot be done from an interrupt.
*
* Note: Toggling a static branch currently causes IPIs, and here we'll end up
* with a total of 2 IPIs to all CPUs. If this ends up a problem in future (with
* more aggressive sampling intervals), we could get away with a variant that
* avoids IPIs, at the cost of not immediately capturing allocations if the
* instructions remain cached.
*/
static void toggle_allocation_gate(struct work_struct *work)
{
if (!READ_ONCE(kfence_enabled))
return;
atomic_set(&kfence_allocation_gate, 0);
#ifdef CONFIG_KFENCE_STATIC_KEYS
/* Enable static key, and await allocation to happen. */
static_branch_enable(&kfence_allocation_key);
wait_event_idle(allocation_wait, atomic_read(&kfence_allocation_gate));
/* Disable static key and reset timer. */
static_branch_disable(&kfence_allocation_key);
#endif
queue_delayed_work(system_unbound_wq, &kfence_timer,
msecs_to_jiffies(kfence_sample_interval));
}
/* === Public interface ===================================================== */
void __init kfence_alloc_pool_and_metadata(void)
{
if (!kfence_sample_interval)
return;
/*
* If the pool has already been initialized by arch, there is no need to
* re-allocate the memory pool.
*/
if (!__kfence_pool)
__kfence_pool = memblock_alloc(KFENCE_POOL_SIZE, PAGE_SIZE);
if (!__kfence_pool) {
pr_err("failed to allocate pool\n");
return;
}
/* The memory allocated by memblock has been zeroed out. */
kfence_metadata_init = memblock_alloc(KFENCE_METADATA_SIZE, PAGE_SIZE);
if (!kfence_metadata_init) {
pr_err("failed to allocate metadata\n");
memblock_free(__kfence_pool, KFENCE_POOL_SIZE);
__kfence_pool = NULL;
}
}
static void kfence_init_enable(void)
{
if (!IS_ENABLED(CONFIG_KFENCE_STATIC_KEYS))
static_branch_enable(&kfence_allocation_key);
if (kfence_deferrable)
INIT_DEFERRABLE_WORK(&kfence_timer, toggle_allocation_gate);
else
INIT_DELAYED_WORK(&kfence_timer, toggle_allocation_gate);
if (kfence_check_on_panic)
atomic_notifier_chain_register(&panic_notifier_list, &kfence_check_canary_notifier);
WRITE_ONCE(kfence_enabled, true);
queue_delayed_work(system_unbound_wq, &kfence_timer, 0);
pr_info("initialized - using %lu bytes for %d objects at 0x%p-0x%p\n", KFENCE_POOL_SIZE,
CONFIG_KFENCE_NUM_OBJECTS, (void *)__kfence_pool,
(void *)(__kfence_pool + KFENCE_POOL_SIZE));
}
void __init kfence_init(void)
{
stack_hash_seed = get_random_u32();
/* Setting kfence_sample_interval to 0 on boot disables KFENCE. */
if (!kfence_sample_interval)
return;
if (!kfence_init_pool_early()) {
pr_err("%s failed\n", __func__);
return;
}
kfence_init_enable();
}
static int kfence_init_late(void)
{
const unsigned long nr_pages_pool = KFENCE_POOL_SIZE / PAGE_SIZE;
const unsigned long nr_pages_meta = KFENCE_METADATA_SIZE / PAGE_SIZE;
unsigned long addr = (unsigned long)__kfence_pool;
unsigned long free_size = KFENCE_POOL_SIZE;
int err = -ENOMEM;
#ifdef CONFIG_CONTIG_ALLOC
struct page *pages;
pages = alloc_contig_pages(nr_pages_pool, GFP_KERNEL, first_online_node,
NULL);
if (!pages)
return -ENOMEM;
__kfence_pool = page_to_virt(pages);
pages = alloc_contig_pages(nr_pages_meta, GFP_KERNEL, first_online_node,
NULL);
if (pages)
kfence_metadata_init = page_to_virt(pages);
#else
if (nr_pages_pool > MAX_ORDER_NR_PAGES ||
nr_pages_meta > MAX_ORDER_NR_PAGES) {
pr_warn("KFENCE_NUM_OBJECTS too large for buddy allocator\n");
return -EINVAL;
}
__kfence_pool = alloc_pages_exact(KFENCE_POOL_SIZE, GFP_KERNEL);
if (!__kfence_pool)
return -ENOMEM;
kfence_metadata_init = alloc_pages_exact(KFENCE_METADATA_SIZE, GFP_KERNEL);
#endif
if (!kfence_metadata_init)
goto free_pool;
memzero_explicit(kfence_metadata_init, KFENCE_METADATA_SIZE);
addr = kfence_init_pool();
if (!addr) {
kfence_init_enable();
kfence_debugfs_init();
return 0;
}
pr_err("%s failed\n", __func__);
free_size = KFENCE_POOL_SIZE - (addr - (unsigned long)__kfence_pool);
err = -EBUSY;
#ifdef CONFIG_CONTIG_ALLOC
free_contig_range(page_to_pfn(virt_to_page((void *)kfence_metadata_init)),
nr_pages_meta);
free_pool:
free_contig_range(page_to_pfn(virt_to_page((void *)addr)),
free_size / PAGE_SIZE);
#else
free_pages_exact((void *)kfence_metadata_init, KFENCE_METADATA_SIZE);
free_pool:
free_pages_exact((void *)addr, free_size);
#endif
kfence_metadata_init = NULL;
__kfence_pool = NULL;
return err;
}
static int kfence_enable_late(void)
{
if (!__kfence_pool)
return kfence_init_late();
WRITE_ONCE(kfence_enabled, true);
queue_delayed_work(system_unbound_wq, &kfence_timer, 0);
pr_info("re-enabled\n");
return 0;
}
void kfence_shutdown_cache(struct kmem_cache *s)
{
unsigned long flags;
struct kfence_metadata *meta;
int i;
/* Pairs with release in kfence_init_pool(). */
if (!smp_load_acquire(&kfence_metadata))
return;
for (i = 0; i < CONFIG_KFENCE_NUM_OBJECTS; i++) {
bool in_use;
meta = &kfence_metadata[i];
/*
* If we observe some inconsistent cache and state pair where we
* should have returned false here, cache destruction is racing
* with either kmem_cache_alloc() or kmem_cache_free(). Taking
* the lock will not help, as different critical section
* serialization will have the same outcome.
*/
if (READ_ONCE(meta->cache) != s ||
READ_ONCE(meta->state) != KFENCE_OBJECT_ALLOCATED)
continue;
raw_spin_lock_irqsave(&meta->lock, flags);
in_use = meta->cache == s && meta->state == KFENCE_OBJECT_ALLOCATED;
raw_spin_unlock_irqrestore(&meta->lock, flags);
if (in_use) {
/*
* This cache still has allocations, and we should not
* release them back into the freelist so they can still
* safely be used and retain the kernel's default
* behaviour of keeping the allocations alive (leak the
* cache); however, they effectively become "zombie
* allocations" as the KFENCE objects are the only ones
* still in use and the owning cache is being destroyed.
*
* We mark them freed, so that any subsequent use shows
* more useful error messages that will include stack
* traces of the user of the object, the original
* allocation, and caller to shutdown_cache().
*/
kfence_guarded_free((void *)meta->addr, meta, /*zombie=*/true);
}
}
for (i = 0; i < CONFIG_KFENCE_NUM_OBJECTS; i++) {
meta = &kfence_metadata[i];
/* See above. */
if (READ_ONCE(meta->cache) != s || READ_ONCE(meta->state) != KFENCE_OBJECT_FREED)
continue;
raw_spin_lock_irqsave(&meta->lock, flags);
if (meta->cache == s && meta->state == KFENCE_OBJECT_FREED)
meta->cache = NULL;
raw_spin_unlock_irqrestore(&meta->lock, flags);
}
}
void *__kfence_alloc(struct kmem_cache *s, size_t size, gfp_t flags)
{
unsigned long stack_entries[KFENCE_STACK_DEPTH];
size_t num_stack_entries;
u32 alloc_stack_hash;
/*
* Perform size check before switching kfence_allocation_gate, so that
* we don't disable KFENCE without making an allocation.
*/
if (size > PAGE_SIZE) {
atomic_long_inc(&counters[KFENCE_COUNTER_SKIP_INCOMPAT]);
return NULL;
}
/*
* Skip allocations from non-default zones, including DMA. We cannot
* guarantee that pages in the KFENCE pool will have the requested
* properties (e.g. reside in DMAable memory).
*/
if ((flags & GFP_ZONEMASK) ||
(s->flags & (SLAB_CACHE_DMA | SLAB_CACHE_DMA32))) {
atomic_long_inc(&counters[KFENCE_COUNTER_SKIP_INCOMPAT]);
return NULL;
}
/*
* Skip allocations for this slab, if KFENCE has been disabled for
* this slab.
*/
if (s->flags & SLAB_SKIP_KFENCE)
return NULL;
if (atomic_inc_return(&kfence_allocation_gate) > 1)
return NULL;
#ifdef CONFIG_KFENCE_STATIC_KEYS
/*
* waitqueue_active() is fully ordered after the update of
* kfence_allocation_gate per atomic_inc_return().
*/
if (waitqueue_active(&allocation_wait)) {
/*
* Calling wake_up() here may deadlock when allocations happen
* from within timer code. Use an irq_work to defer it.
*/
irq_work_queue(&wake_up_kfence_timer_work);
}
#endif
if (!READ_ONCE(kfence_enabled))
return NULL;
num_stack_entries = stack_trace_save(stack_entries, KFENCE_STACK_DEPTH, 0);
/*
* Do expensive check for coverage of allocation in slow-path after
* allocation_gate has already become non-zero, even though it might
* mean not making any allocation within a given sample interval.
*
* This ensures reasonable allocation coverage when the pool is almost
* full, including avoiding long-lived allocations of the same source
* filling up the pool (e.g. pagecache allocations).
*/
alloc_stack_hash = get_alloc_stack_hash(stack_entries, num_stack_entries);
if (should_skip_covered() && alloc_covered_contains(alloc_stack_hash)) {
atomic_long_inc(&counters[KFENCE_COUNTER_SKIP_COVERED]);
return NULL;
}
return kfence_guarded_alloc(s, size, flags, stack_entries, num_stack_entries,
alloc_stack_hash);
}
size_t kfence_ksize(const void *addr)
{
const struct kfence_metadata *meta = addr_to_metadata((unsigned long)addr);
/*
* Read locklessly -- if there is a race with __kfence_alloc(), this is
* either a use-after-free or invalid access.
*/
return meta ? meta->size : 0;
}
void *kfence_object_start(const void *addr)
{
const struct kfence_metadata *meta = addr_to_metadata((unsigned long)addr);
/*
* Read locklessly -- if there is a race with __kfence_alloc(), this is
* either a use-after-free or invalid access.
*/
return meta ? (void *)meta->addr : NULL;
}
void __kfence_free(void *addr)
{
struct kfence_metadata *meta = addr_to_metadata((unsigned long)addr);
#ifdef CONFIG_MEMCG
KFENCE_WARN_ON(meta->objcg);
#endif
/*
* If the objects of the cache are SLAB_TYPESAFE_BY_RCU, defer freeing
* the object, as the object page may be recycled for other-typed
* objects once it has been freed. meta->cache may be NULL if the cache
* was destroyed.
*/
if (unlikely(meta->cache && (meta->cache->flags & SLAB_TYPESAFE_BY_RCU)))
call_rcu(&meta->rcu_head, rcu_guarded_free);
else
kfence_guarded_free(addr, meta, false);
}
bool kfence_handle_page_fault(unsigned long addr, bool is_write, struct pt_regs *regs)
{
const int page_index = (addr - (unsigned long)__kfence_pool) / PAGE_SIZE;
struct kfence_metadata *to_report = NULL;
enum kfence_error_type error_type;
unsigned long flags;
if (!is_kfence_address((void *)addr))
return false;
if (!READ_ONCE(kfence_enabled)) /* If disabled at runtime ... */
return kfence_unprotect(addr); /* ... unprotect and proceed. */
atomic_long_inc(&counters[KFENCE_COUNTER_BUGS]);
if (page_index % 2) {
/* This is a redzone, report a buffer overflow. */
struct kfence_metadata *meta;
int distance = 0;
meta = addr_to_metadata(addr - PAGE_SIZE);
if (meta && READ_ONCE(meta->state) == KFENCE_OBJECT_ALLOCATED) {
to_report = meta;
/* Data race ok; distance calculation approximate. */
distance = addr - data_race(meta->addr + meta->size);
}
meta = addr_to_metadata(addr + PAGE_SIZE);
if (meta && READ_ONCE(meta->state) == KFENCE_OBJECT_ALLOCATED) {
/* Data race ok; distance calculation approximate. */
if (!to_report || distance > data_race(meta->addr) - addr)
to_report = meta;
}
if (!to_report)
goto out;
raw_spin_lock_irqsave(&to_report->lock, flags);
to_report->unprotected_page = addr;
error_type = KFENCE_ERROR_OOB;
/*
* If the object was freed before we took the look we can still
* report this as an OOB -- the report will simply show the
* stacktrace of the free as well.
*/
} else {
to_report = addr_to_metadata(addr);
if (!to_report)
goto out;
raw_spin_lock_irqsave(&to_report->lock, flags);
error_type = KFENCE_ERROR_UAF;
/*
* We may race with __kfence_alloc(), and it is possible that a
* freed object may be reallocated. We simply report this as a
* use-after-free, with the stack trace showing the place where
* the object was re-allocated.
*/
}
out:
if (to_report) {
kfence_report_error(addr, is_write, regs, to_report, error_type);
raw_spin_unlock_irqrestore(&to_report->lock, flags);
} else {
/* This may be a UAF or OOB access, but we can't be sure. */
kfence_report_error(addr, is_write, regs, NULL, KFENCE_ERROR_INVALID);
}
return kfence_unprotect(addr); /* Unprotect and let access proceed. */
}
| linux-master | mm/kfence/core.c |
// SPDX-License-Identifier: GPL-2.0
/*
* KMSAN shadow implementation.
*
* Copyright (C) 2017-2022 Google LLC
* Author: Alexander Potapenko <[email protected]>
*
*/
#include <asm/kmsan.h>
#include <asm/tlbflush.h>
#include <linux/cacheflush.h>
#include <linux/memblock.h>
#include <linux/mm_types.h>
#include <linux/slab.h>
#include <linux/smp.h>
#include <linux/stddef.h>
#include "../internal.h"
#include "kmsan.h"
#define shadow_page_for(page) ((page)->kmsan_shadow)
#define origin_page_for(page) ((page)->kmsan_origin)
static void *shadow_ptr_for(struct page *page)
{
return page_address(shadow_page_for(page));
}
static void *origin_ptr_for(struct page *page)
{
return page_address(origin_page_for(page));
}
static bool page_has_metadata(struct page *page)
{
return shadow_page_for(page) && origin_page_for(page);
}
static void set_no_shadow_origin_page(struct page *page)
{
shadow_page_for(page) = NULL;
origin_page_for(page) = NULL;
}
/*
* Dummy load and store pages to be used when the real metadata is unavailable.
* There are separate pages for loads and stores, so that every load returns a
* zero, and every store doesn't affect other loads.
*/
static char dummy_load_page[PAGE_SIZE] __aligned(PAGE_SIZE);
static char dummy_store_page[PAGE_SIZE] __aligned(PAGE_SIZE);
static unsigned long vmalloc_meta(void *addr, bool is_origin)
{
unsigned long addr64 = (unsigned long)addr, off;
KMSAN_WARN_ON(is_origin && !IS_ALIGNED(addr64, KMSAN_ORIGIN_SIZE));
if (kmsan_internal_is_vmalloc_addr(addr)) {
off = addr64 - VMALLOC_START;
return off + (is_origin ? KMSAN_VMALLOC_ORIGIN_START :
KMSAN_VMALLOC_SHADOW_START);
}
if (kmsan_internal_is_module_addr(addr)) {
off = addr64 - MODULES_VADDR;
return off + (is_origin ? KMSAN_MODULES_ORIGIN_START :
KMSAN_MODULES_SHADOW_START);
}
return 0;
}
static struct page *virt_to_page_or_null(void *vaddr)
{
if (kmsan_virt_addr_valid(vaddr))
return virt_to_page(vaddr);
else
return NULL;
}
struct shadow_origin_ptr kmsan_get_shadow_origin_ptr(void *address, u64 size,
bool store)
{
struct shadow_origin_ptr ret;
void *shadow;
/*
* Even if we redirect this memory access to the dummy page, it will
* go out of bounds.
*/
KMSAN_WARN_ON(size > PAGE_SIZE);
if (!kmsan_enabled)
goto return_dummy;
KMSAN_WARN_ON(!kmsan_metadata_is_contiguous(address, size));
shadow = kmsan_get_metadata(address, KMSAN_META_SHADOW);
if (!shadow)
goto return_dummy;
ret.shadow = shadow;
ret.origin = kmsan_get_metadata(address, KMSAN_META_ORIGIN);
return ret;
return_dummy:
if (store) {
/* Ignore this store. */
ret.shadow = dummy_store_page;
ret.origin = dummy_store_page;
} else {
/* This load will return zero. */
ret.shadow = dummy_load_page;
ret.origin = dummy_load_page;
}
return ret;
}
/*
* Obtain the shadow or origin pointer for the given address, or NULL if there's
* none. The caller must check the return value for being non-NULL if needed.
* The return value of this function should not depend on whether we're in the
* runtime or not.
*/
void *kmsan_get_metadata(void *address, bool is_origin)
{
u64 addr = (u64)address, pad, off;
struct page *page;
void *ret;
if (is_origin && !IS_ALIGNED(addr, KMSAN_ORIGIN_SIZE)) {
pad = addr % KMSAN_ORIGIN_SIZE;
addr -= pad;
}
address = (void *)addr;
if (kmsan_internal_is_vmalloc_addr(address) ||
kmsan_internal_is_module_addr(address))
return (void *)vmalloc_meta(address, is_origin);
ret = arch_kmsan_get_meta_or_null(address, is_origin);
if (ret)
return ret;
page = virt_to_page_or_null(address);
if (!page)
return NULL;
if (!page_has_metadata(page))
return NULL;
off = offset_in_page(addr);
return (is_origin ? origin_ptr_for(page) : shadow_ptr_for(page)) + off;
}
void kmsan_copy_page_meta(struct page *dst, struct page *src)
{
if (!kmsan_enabled || kmsan_in_runtime())
return;
if (!dst || !page_has_metadata(dst))
return;
if (!src || !page_has_metadata(src)) {
kmsan_internal_unpoison_memory(page_address(dst), PAGE_SIZE,
/*checked*/ false);
return;
}
kmsan_enter_runtime();
__memcpy(shadow_ptr_for(dst), shadow_ptr_for(src), PAGE_SIZE);
__memcpy(origin_ptr_for(dst), origin_ptr_for(src), PAGE_SIZE);
kmsan_leave_runtime();
}
EXPORT_SYMBOL(kmsan_copy_page_meta);
void kmsan_alloc_page(struct page *page, unsigned int order, gfp_t flags)
{
bool initialized = (flags & __GFP_ZERO) || !kmsan_enabled;
struct page *shadow, *origin;
depot_stack_handle_t handle;
int pages = 1 << order;
if (!page)
return;
shadow = shadow_page_for(page);
origin = origin_page_for(page);
if (initialized) {
__memset(page_address(shadow), 0, PAGE_SIZE * pages);
__memset(page_address(origin), 0, PAGE_SIZE * pages);
return;
}
/* Zero pages allocated by the runtime should also be initialized. */
if (kmsan_in_runtime())
return;
__memset(page_address(shadow), -1, PAGE_SIZE * pages);
kmsan_enter_runtime();
handle = kmsan_save_stack_with_flags(flags, /*extra_bits*/ 0);
kmsan_leave_runtime();
/*
* Addresses are page-aligned, pages are contiguous, so it's ok
* to just fill the origin pages with @handle.
*/
for (int i = 0; i < PAGE_SIZE * pages / sizeof(handle); i++)
((depot_stack_handle_t *)page_address(origin))[i] = handle;
}
void kmsan_free_page(struct page *page, unsigned int order)
{
if (!kmsan_enabled || kmsan_in_runtime())
return;
kmsan_enter_runtime();
kmsan_internal_poison_memory(page_address(page),
page_size(page),
GFP_KERNEL,
KMSAN_POISON_CHECK | KMSAN_POISON_FREE);
kmsan_leave_runtime();
}
int kmsan_vmap_pages_range_noflush(unsigned long start, unsigned long end,
pgprot_t prot, struct page **pages,
unsigned int page_shift)
{
unsigned long shadow_start, origin_start, shadow_end, origin_end;
struct page **s_pages, **o_pages;
int nr, mapped, err = 0;
if (!kmsan_enabled)
return 0;
shadow_start = vmalloc_meta((void *)start, KMSAN_META_SHADOW);
shadow_end = vmalloc_meta((void *)end, KMSAN_META_SHADOW);
if (!shadow_start)
return 0;
nr = (end - start) / PAGE_SIZE;
s_pages = kcalloc(nr, sizeof(*s_pages), GFP_KERNEL);
o_pages = kcalloc(nr, sizeof(*o_pages), GFP_KERNEL);
if (!s_pages || !o_pages) {
err = -ENOMEM;
goto ret;
}
for (int i = 0; i < nr; i++) {
s_pages[i] = shadow_page_for(pages[i]);
o_pages[i] = origin_page_for(pages[i]);
}
prot = __pgprot(pgprot_val(prot) | _PAGE_NX);
prot = PAGE_KERNEL;
origin_start = vmalloc_meta((void *)start, KMSAN_META_ORIGIN);
origin_end = vmalloc_meta((void *)end, KMSAN_META_ORIGIN);
kmsan_enter_runtime();
mapped = __vmap_pages_range_noflush(shadow_start, shadow_end, prot,
s_pages, page_shift);
if (mapped) {
err = mapped;
goto ret;
}
mapped = __vmap_pages_range_noflush(origin_start, origin_end, prot,
o_pages, page_shift);
if (mapped) {
err = mapped;
goto ret;
}
kmsan_leave_runtime();
flush_tlb_kernel_range(shadow_start, shadow_end);
flush_tlb_kernel_range(origin_start, origin_end);
flush_cache_vmap(shadow_start, shadow_end);
flush_cache_vmap(origin_start, origin_end);
ret:
kfree(s_pages);
kfree(o_pages);
return err;
}
/* Allocate metadata for pages allocated at boot time. */
void __init kmsan_init_alloc_meta_for_range(void *start, void *end)
{
struct page *shadow_p, *origin_p;
void *shadow, *origin;
struct page *page;
u64 size;
start = (void *)PAGE_ALIGN_DOWN((u64)start);
size = PAGE_ALIGN((u64)end - (u64)start);
shadow = memblock_alloc(size, PAGE_SIZE);
origin = memblock_alloc(size, PAGE_SIZE);
for (u64 addr = 0; addr < size; addr += PAGE_SIZE) {
page = virt_to_page_or_null((char *)start + addr);
shadow_p = virt_to_page_or_null((char *)shadow + addr);
set_no_shadow_origin_page(shadow_p);
shadow_page_for(page) = shadow_p;
origin_p = virt_to_page_or_null((char *)origin + addr);
set_no_shadow_origin_page(origin_p);
origin_page_for(page) = origin_p;
}
}
void kmsan_setup_meta(struct page *page, struct page *shadow,
struct page *origin, int order)
{
for (int i = 0; i < (1 << order); i++) {
set_no_shadow_origin_page(&shadow[i]);
set_no_shadow_origin_page(&origin[i]);
shadow_page_for(&page[i]) = &shadow[i];
origin_page_for(&page[i]) = &origin[i];
}
}
| linux-master | mm/kmsan/shadow.c |
// SPDX-License-Identifier: GPL-2.0
/*
* KMSAN compiler API.
*
* This file implements __msan_XXX hooks that Clang inserts into the code
* compiled with -fsanitize=kernel-memory.
* See Documentation/dev-tools/kmsan.rst for more information on how KMSAN
* instrumentation works.
*
* Copyright (C) 2017-2022 Google LLC
* Author: Alexander Potapenko <[email protected]>
*
*/
#include "kmsan.h"
#include <linux/gfp.h>
#include <linux/kmsan_string.h>
#include <linux/mm.h>
#include <linux/uaccess.h>
static inline bool is_bad_asm_addr(void *addr, uintptr_t size, bool is_store)
{
if ((u64)addr < TASK_SIZE)
return true;
if (!kmsan_get_metadata(addr, KMSAN_META_SHADOW))
return true;
return false;
}
static inline struct shadow_origin_ptr
get_shadow_origin_ptr(void *addr, u64 size, bool store)
{
unsigned long ua_flags = user_access_save();
struct shadow_origin_ptr ret;
ret = kmsan_get_shadow_origin_ptr(addr, size, store);
user_access_restore(ua_flags);
return ret;
}
/*
* KMSAN instrumentation functions follow. They are not declared elsewhere in
* the kernel code, so they are preceded by prototypes, to silence
* -Wmissing-prototypes warnings.
*/
/* Get shadow and origin pointers for a memory load with non-standard size. */
struct shadow_origin_ptr __msan_metadata_ptr_for_load_n(void *addr,
uintptr_t size);
struct shadow_origin_ptr __msan_metadata_ptr_for_load_n(void *addr,
uintptr_t size)
{
return get_shadow_origin_ptr(addr, size, /*store*/ false);
}
EXPORT_SYMBOL(__msan_metadata_ptr_for_load_n);
/* Get shadow and origin pointers for a memory store with non-standard size. */
struct shadow_origin_ptr __msan_metadata_ptr_for_store_n(void *addr,
uintptr_t size);
struct shadow_origin_ptr __msan_metadata_ptr_for_store_n(void *addr,
uintptr_t size)
{
return get_shadow_origin_ptr(addr, size, /*store*/ true);
}
EXPORT_SYMBOL(__msan_metadata_ptr_for_store_n);
/*
* Declare functions that obtain shadow/origin pointers for loads and stores
* with fixed size.
*/
#define DECLARE_METADATA_PTR_GETTER(size) \
struct shadow_origin_ptr __msan_metadata_ptr_for_load_##size( \
void *addr); \
struct shadow_origin_ptr __msan_metadata_ptr_for_load_##size( \
void *addr) \
{ \
return get_shadow_origin_ptr(addr, size, /*store*/ false); \
} \
EXPORT_SYMBOL(__msan_metadata_ptr_for_load_##size); \
struct shadow_origin_ptr __msan_metadata_ptr_for_store_##size( \
void *addr); \
struct shadow_origin_ptr __msan_metadata_ptr_for_store_##size( \
void *addr) \
{ \
return get_shadow_origin_ptr(addr, size, /*store*/ true); \
} \
EXPORT_SYMBOL(__msan_metadata_ptr_for_store_##size)
DECLARE_METADATA_PTR_GETTER(1);
DECLARE_METADATA_PTR_GETTER(2);
DECLARE_METADATA_PTR_GETTER(4);
DECLARE_METADATA_PTR_GETTER(8);
/*
* Handle a memory store performed by inline assembly. KMSAN conservatively
* attempts to unpoison the outputs of asm() directives to prevent false
* positives caused by missed stores.
*
* __msan_instrument_asm_store() may be called for inline assembly code when
* entering or leaving IRQ. We omit the check for kmsan_in_runtime() to ensure
* the memory written to in these cases is also marked as initialized.
*/
void __msan_instrument_asm_store(void *addr, uintptr_t size);
void __msan_instrument_asm_store(void *addr, uintptr_t size)
{
unsigned long ua_flags;
if (!kmsan_enabled)
return;
ua_flags = user_access_save();
/*
* Most of the accesses are below 32 bytes. The two exceptions so far
* are clwb() (64 bytes) and FPU state (512 bytes).
* It's unlikely that the assembly will touch more than 512 bytes.
*/
if (size > 512) {
WARN_ONCE(1, "assembly store size too big: %ld\n", size);
size = 8;
}
if (is_bad_asm_addr(addr, size, /*is_store*/ true)) {
user_access_restore(ua_flags);
return;
}
/* Unpoisoning the memory on best effort. */
kmsan_internal_unpoison_memory(addr, size, /*checked*/ false);
user_access_restore(ua_flags);
}
EXPORT_SYMBOL(__msan_instrument_asm_store);
/*
* KMSAN instrumentation pass replaces LLVM memcpy, memmove and memset
* intrinsics with calls to respective __msan_ functions. We use
* get_param0_metadata() and set_retval_metadata() to store the shadow/origin
* values for the destination argument of these functions and use them for the
* functions' return values.
*/
static inline void get_param0_metadata(u64 *shadow,
depot_stack_handle_t *origin)
{
struct kmsan_ctx *ctx = kmsan_get_context();
*shadow = *(u64 *)(ctx->cstate.param_tls);
*origin = ctx->cstate.param_origin_tls[0];
}
static inline void set_retval_metadata(u64 shadow, depot_stack_handle_t origin)
{
struct kmsan_ctx *ctx = kmsan_get_context();
*(u64 *)(ctx->cstate.retval_tls) = shadow;
ctx->cstate.retval_origin_tls = origin;
}
/* Handle llvm.memmove intrinsic. */
void *__msan_memmove(void *dst, const void *src, uintptr_t n);
void *__msan_memmove(void *dst, const void *src, uintptr_t n)
{
depot_stack_handle_t origin;
void *result;
u64 shadow;
get_param0_metadata(&shadow, &origin);
result = __memmove(dst, src, n);
if (!n)
/* Some people call memmove() with zero length. */
return result;
if (!kmsan_enabled || kmsan_in_runtime())
return result;
kmsan_enter_runtime();
kmsan_internal_memmove_metadata(dst, (void *)src, n);
kmsan_leave_runtime();
set_retval_metadata(shadow, origin);
return result;
}
EXPORT_SYMBOL(__msan_memmove);
/* Handle llvm.memcpy intrinsic. */
void *__msan_memcpy(void *dst, const void *src, uintptr_t n);
void *__msan_memcpy(void *dst, const void *src, uintptr_t n)
{
depot_stack_handle_t origin;
void *result;
u64 shadow;
get_param0_metadata(&shadow, &origin);
result = __memcpy(dst, src, n);
if (!n)
/* Some people call memcpy() with zero length. */
return result;
if (!kmsan_enabled || kmsan_in_runtime())
return result;
kmsan_enter_runtime();
/* Using memmove instead of memcpy doesn't affect correctness. */
kmsan_internal_memmove_metadata(dst, (void *)src, n);
kmsan_leave_runtime();
set_retval_metadata(shadow, origin);
return result;
}
EXPORT_SYMBOL(__msan_memcpy);
/* Handle llvm.memset intrinsic. */
void *__msan_memset(void *dst, int c, uintptr_t n);
void *__msan_memset(void *dst, int c, uintptr_t n)
{
depot_stack_handle_t origin;
void *result;
u64 shadow;
get_param0_metadata(&shadow, &origin);
result = __memset(dst, c, n);
if (!kmsan_enabled || kmsan_in_runtime())
return result;
kmsan_enter_runtime();
/*
* Clang doesn't pass parameter metadata here, so it is impossible to
* use shadow of @c to set up the shadow for @dst.
*/
kmsan_internal_unpoison_memory(dst, n, /*checked*/ false);
kmsan_leave_runtime();
set_retval_metadata(shadow, origin);
return result;
}
EXPORT_SYMBOL(__msan_memset);
/*
* Create a new origin from an old one. This is done when storing an
* uninitialized value to memory. When reporting an error, KMSAN unrolls and
* prints the whole chain of stores that preceded the use of this value.
*/
depot_stack_handle_t __msan_chain_origin(depot_stack_handle_t origin);
depot_stack_handle_t __msan_chain_origin(depot_stack_handle_t origin)
{
depot_stack_handle_t ret = 0;
unsigned long ua_flags;
if (!kmsan_enabled || kmsan_in_runtime())
return ret;
ua_flags = user_access_save();
/* Creating new origins may allocate memory. */
kmsan_enter_runtime();
ret = kmsan_internal_chain_origin(origin);
kmsan_leave_runtime();
user_access_restore(ua_flags);
return ret;
}
EXPORT_SYMBOL(__msan_chain_origin);
/* Poison a local variable when entering a function. */
void __msan_poison_alloca(void *address, uintptr_t size, char *descr);
void __msan_poison_alloca(void *address, uintptr_t size, char *descr)
{
depot_stack_handle_t handle;
unsigned long entries[4];
unsigned long ua_flags;
if (!kmsan_enabled || kmsan_in_runtime())
return;
ua_flags = user_access_save();
entries[0] = KMSAN_ALLOCA_MAGIC_ORIGIN;
entries[1] = (u64)descr;
entries[2] = (u64)__builtin_return_address(0);
/*
* With frame pointers enabled, it is possible to quickly fetch the
* second frame of the caller stack without calling the unwinder.
* Without them, simply do not bother.
*/
if (IS_ENABLED(CONFIG_UNWINDER_FRAME_POINTER))
entries[3] = (u64)__builtin_return_address(1);
else
entries[3] = 0;
/* stack_depot_save() may allocate memory. */
kmsan_enter_runtime();
handle = stack_depot_save(entries, ARRAY_SIZE(entries), __GFP_HIGH);
kmsan_leave_runtime();
kmsan_internal_set_shadow_origin(address, size, -1, handle,
/*checked*/ true);
user_access_restore(ua_flags);
}
EXPORT_SYMBOL(__msan_poison_alloca);
/* Unpoison a local variable. */
void __msan_unpoison_alloca(void *address, uintptr_t size);
void __msan_unpoison_alloca(void *address, uintptr_t size)
{
if (!kmsan_enabled || kmsan_in_runtime())
return;
kmsan_enter_runtime();
kmsan_internal_unpoison_memory(address, size, /*checked*/ true);
kmsan_leave_runtime();
}
EXPORT_SYMBOL(__msan_unpoison_alloca);
/*
* Report that an uninitialized value with the given origin was used in a way
* that constituted undefined behavior.
*/
void __msan_warning(u32 origin);
void __msan_warning(u32 origin)
{
if (!kmsan_enabled || kmsan_in_runtime())
return;
kmsan_enter_runtime();
kmsan_report(origin, /*address*/ 0, /*size*/ 0,
/*off_first*/ 0, /*off_last*/ 0, /*user_addr*/ 0,
REASON_ANY);
kmsan_leave_runtime();
}
EXPORT_SYMBOL(__msan_warning);
/*
* At the beginning of an instrumented function, obtain the pointer to
* `struct kmsan_context_state` holding the metadata for function parameters.
*/
struct kmsan_context_state *__msan_get_context_state(void);
struct kmsan_context_state *__msan_get_context_state(void)
{
return &kmsan_get_context()->cstate;
}
EXPORT_SYMBOL(__msan_get_context_state);
| linux-master | mm/kmsan/instrumentation.c |
// SPDX-License-Identifier: GPL-2.0
/*
* KMSAN error reporting routines.
*
* Copyright (C) 2019-2022 Google LLC
* Author: Alexander Potapenko <[email protected]>
*
*/
#include <linux/console.h>
#include <linux/moduleparam.h>
#include <linux/stackdepot.h>
#include <linux/stacktrace.h>
#include <linux/uaccess.h>
#include "kmsan.h"
static DEFINE_RAW_SPINLOCK(kmsan_report_lock);
#define DESCR_SIZE 128
/* Protected by kmsan_report_lock */
static char report_local_descr[DESCR_SIZE];
int panic_on_kmsan __read_mostly;
#ifdef MODULE_PARAM_PREFIX
#undef MODULE_PARAM_PREFIX
#endif
#define MODULE_PARAM_PREFIX "kmsan."
module_param_named(panic, panic_on_kmsan, int, 0);
/*
* Skip internal KMSAN frames.
*/
static int get_stack_skipnr(const unsigned long stack_entries[],
int num_entries)
{
int len, skip;
char buf[64];
for (skip = 0; skip < num_entries; ++skip) {
len = scnprintf(buf, sizeof(buf), "%ps",
(void *)stack_entries[skip]);
/* Never show __msan_* or kmsan_* functions. */
if ((strnstr(buf, "__msan_", len) == buf) ||
(strnstr(buf, "kmsan_", len) == buf))
continue;
/*
* No match for runtime functions -- @skip entries to skip to
* get to first frame of interest.
*/
break;
}
return skip;
}
/*
* Currently the descriptions of locals generated by Clang look as follows:
* ----local_name@function_name
* We want to print only the name of the local, as other information in that
* description can be confusing.
* The meaningful part of the description is copied to a global buffer to avoid
* allocating memory.
*/
static char *pretty_descr(char *descr)
{
int pos = 0, len = strlen(descr);
for (int i = 0; i < len; i++) {
if (descr[i] == '@')
break;
if (descr[i] == '-')
continue;
report_local_descr[pos] = descr[i];
if (pos + 1 == DESCR_SIZE)
break;
pos++;
}
report_local_descr[pos] = 0;
return report_local_descr;
}
void kmsan_print_origin(depot_stack_handle_t origin)
{
unsigned long *entries = NULL, *chained_entries = NULL;
unsigned int nr_entries, chained_nr_entries, skipnr;
void *pc1 = NULL, *pc2 = NULL;
depot_stack_handle_t head;
unsigned long magic;
char *descr = NULL;
unsigned int depth;
if (!origin)
return;
while (true) {
nr_entries = stack_depot_fetch(origin, &entries);
depth = kmsan_depth_from_eb(stack_depot_get_extra_bits(origin));
magic = nr_entries ? entries[0] : 0;
if ((nr_entries == 4) && (magic == KMSAN_ALLOCA_MAGIC_ORIGIN)) {
descr = (char *)entries[1];
pc1 = (void *)entries[2];
pc2 = (void *)entries[3];
pr_err("Local variable %s created at:\n",
pretty_descr(descr));
if (pc1)
pr_err(" %pSb\n", pc1);
if (pc2)
pr_err(" %pSb\n", pc2);
break;
}
if ((nr_entries == 3) && (magic == KMSAN_CHAIN_MAGIC_ORIGIN)) {
/*
* Origin chains deeper than KMSAN_MAX_ORIGIN_DEPTH are
* not stored, so the output may be incomplete.
*/
if (depth == KMSAN_MAX_ORIGIN_DEPTH)
pr_err("<Zero or more stacks not recorded to save memory>\n\n");
head = entries[1];
origin = entries[2];
pr_err("Uninit was stored to memory at:\n");
chained_nr_entries =
stack_depot_fetch(head, &chained_entries);
kmsan_internal_unpoison_memory(
chained_entries,
chained_nr_entries * sizeof(*chained_entries),
/*checked*/ false);
skipnr = get_stack_skipnr(chained_entries,
chained_nr_entries);
stack_trace_print(chained_entries + skipnr,
chained_nr_entries - skipnr, 0);
pr_err("\n");
continue;
}
pr_err("Uninit was created at:\n");
if (nr_entries) {
skipnr = get_stack_skipnr(entries, nr_entries);
stack_trace_print(entries + skipnr, nr_entries - skipnr,
0);
} else {
pr_err("(stack is not available)\n");
}
break;
}
}
void kmsan_report(depot_stack_handle_t origin, void *address, int size,
int off_first, int off_last, const void *user_addr,
enum kmsan_bug_reason reason)
{
unsigned long stack_entries[KMSAN_STACK_DEPTH];
int num_stack_entries, skipnr;
char *bug_type = NULL;
unsigned long ua_flags;
bool is_uaf;
if (!kmsan_enabled)
return;
if (!current->kmsan_ctx.allow_reporting)
return;
if (!origin)
return;
current->kmsan_ctx.allow_reporting = false;
ua_flags = user_access_save();
raw_spin_lock(&kmsan_report_lock);
pr_err("=====================================================\n");
is_uaf = kmsan_uaf_from_eb(stack_depot_get_extra_bits(origin));
switch (reason) {
case REASON_ANY:
bug_type = is_uaf ? "use-after-free" : "uninit-value";
break;
case REASON_COPY_TO_USER:
bug_type = is_uaf ? "kernel-infoleak-after-free" :
"kernel-infoleak";
break;
case REASON_SUBMIT_URB:
bug_type = is_uaf ? "kernel-usb-infoleak-after-free" :
"kernel-usb-infoleak";
break;
}
num_stack_entries =
stack_trace_save(stack_entries, KMSAN_STACK_DEPTH, 1);
skipnr = get_stack_skipnr(stack_entries, num_stack_entries);
pr_err("BUG: KMSAN: %s in %pSb\n", bug_type,
(void *)stack_entries[skipnr]);
stack_trace_print(stack_entries + skipnr, num_stack_entries - skipnr,
0);
pr_err("\n");
kmsan_print_origin(origin);
if (size) {
pr_err("\n");
if (off_first == off_last)
pr_err("Byte %d of %d is uninitialized\n", off_first,
size);
else
pr_err("Bytes %d-%d of %d are uninitialized\n",
off_first, off_last, size);
}
if (address)
pr_err("Memory access of size %d starts at %px\n", size,
address);
if (user_addr && reason == REASON_COPY_TO_USER)
pr_err("Data copied to user address %px\n", user_addr);
pr_err("\n");
dump_stack_print_info(KERN_ERR);
pr_err("=====================================================\n");
add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
raw_spin_unlock(&kmsan_report_lock);
if (panic_on_kmsan)
panic("kmsan.panic set ...\n");
user_access_restore(ua_flags);
current->kmsan_ctx.allow_reporting = true;
}
| linux-master | mm/kmsan/report.c |
// SPDX-License-Identifier: GPL-2.0
/*
* KMSAN initialization routines.
*
* Copyright (C) 2017-2021 Google LLC
* Author: Alexander Potapenko <[email protected]>
*
*/
#include "kmsan.h"
#include <asm/sections.h>
#include <linux/mm.h>
#include <linux/memblock.h>
#include "../internal.h"
#define NUM_FUTURE_RANGES 128
struct start_end_pair {
u64 start, end;
};
static struct start_end_pair start_end_pairs[NUM_FUTURE_RANGES] __initdata;
static int future_index __initdata;
/*
* Record a range of memory for which the metadata pages will be created once
* the page allocator becomes available.
*/
static void __init kmsan_record_future_shadow_range(void *start, void *end)
{
u64 nstart = (u64)start, nend = (u64)end, cstart, cend;
bool merged = false;
KMSAN_WARN_ON(future_index == NUM_FUTURE_RANGES);
KMSAN_WARN_ON((nstart >= nend) || !nstart || !nend);
nstart = ALIGN_DOWN(nstart, PAGE_SIZE);
nend = ALIGN(nend, PAGE_SIZE);
/*
* Scan the existing ranges to see if any of them overlaps with
* [start, end). In that case, merge the two ranges instead of
* creating a new one.
* The number of ranges is less than 20, so there is no need to organize
* them into a more intelligent data structure.
*/
for (int i = 0; i < future_index; i++) {
cstart = start_end_pairs[i].start;
cend = start_end_pairs[i].end;
if ((cstart < nstart && cend < nstart) ||
(cstart > nend && cend > nend))
/* ranges are disjoint - do not merge */
continue;
start_end_pairs[i].start = min(nstart, cstart);
start_end_pairs[i].end = max(nend, cend);
merged = true;
break;
}
if (merged)
return;
start_end_pairs[future_index].start = nstart;
start_end_pairs[future_index].end = nend;
future_index++;
}
/*
* Initialize the shadow for existing mappings during kernel initialization.
* These include kernel text/data sections, NODE_DATA and future ranges
* registered while creating other data (e.g. percpu).
*
* Allocations via memblock can be only done before slab is initialized.
*/
void __init kmsan_init_shadow(void)
{
const size_t nd_size = roundup(sizeof(pg_data_t), PAGE_SIZE);
phys_addr_t p_start, p_end;
u64 loop;
int nid;
for_each_reserved_mem_range(loop, &p_start, &p_end)
kmsan_record_future_shadow_range(phys_to_virt(p_start),
phys_to_virt(p_end));
/* Allocate shadow for .data */
kmsan_record_future_shadow_range(_sdata, _edata);
for_each_online_node(nid)
kmsan_record_future_shadow_range(
NODE_DATA(nid), (char *)NODE_DATA(nid) + nd_size);
for (int i = 0; i < future_index; i++)
kmsan_init_alloc_meta_for_range(
(void *)start_end_pairs[i].start,
(void *)start_end_pairs[i].end);
}
struct metadata_page_pair {
struct page *shadow, *origin;
};
static struct metadata_page_pair held_back[MAX_ORDER + 1] __initdata;
/*
* Eager metadata allocation. When the memblock allocator is freeing pages to
* pagealloc, we use 2/3 of them as metadata for the remaining 1/3.
* We store the pointers to the returned blocks of pages in held_back[] grouped
* by their order: when kmsan_memblock_free_pages() is called for the first
* time with a certain order, it is reserved as a shadow block, for the second
* time - as an origin block. On the third time the incoming block receives its
* shadow and origin ranges from the previously saved shadow and origin blocks,
* after which held_back[order] can be used again.
*
* At the very end there may be leftover blocks in held_back[]. They are
* collected later by kmsan_memblock_discard().
*/
bool kmsan_memblock_free_pages(struct page *page, unsigned int order)
{
struct page *shadow, *origin;
if (!held_back[order].shadow) {
held_back[order].shadow = page;
return false;
}
if (!held_back[order].origin) {
held_back[order].origin = page;
return false;
}
shadow = held_back[order].shadow;
origin = held_back[order].origin;
kmsan_setup_meta(page, shadow, origin, order);
held_back[order].shadow = NULL;
held_back[order].origin = NULL;
return true;
}
#define MAX_BLOCKS 8
struct smallstack {
struct page *items[MAX_BLOCKS];
int index;
int order;
};
static struct smallstack collect = {
.index = 0,
.order = MAX_ORDER,
};
static void smallstack_push(struct smallstack *stack, struct page *pages)
{
KMSAN_WARN_ON(stack->index == MAX_BLOCKS);
stack->items[stack->index] = pages;
stack->index++;
}
#undef MAX_BLOCKS
static struct page *smallstack_pop(struct smallstack *stack)
{
struct page *ret;
KMSAN_WARN_ON(stack->index == 0);
stack->index--;
ret = stack->items[stack->index];
stack->items[stack->index] = NULL;
return ret;
}
static void do_collection(void)
{
struct page *page, *shadow, *origin;
while (collect.index >= 3) {
page = smallstack_pop(&collect);
shadow = smallstack_pop(&collect);
origin = smallstack_pop(&collect);
kmsan_setup_meta(page, shadow, origin, collect.order);
__free_pages_core(page, collect.order);
}
}
static void collect_split(void)
{
struct smallstack tmp = {
.order = collect.order - 1,
.index = 0,
};
struct page *page;
if (!collect.order)
return;
while (collect.index) {
page = smallstack_pop(&collect);
smallstack_push(&tmp, &page[0]);
smallstack_push(&tmp, &page[1 << tmp.order]);
}
__memcpy(&collect, &tmp, sizeof(tmp));
}
/*
* Memblock is about to go away. Split the page blocks left over in held_back[]
* and return 1/3 of that memory to the system.
*/
static void kmsan_memblock_discard(void)
{
/*
* For each order=N:
* - push held_back[N].shadow and .origin to @collect;
* - while there are >= 3 elements in @collect, do garbage collection:
* - pop 3 ranges from @collect;
* - use two of them as shadow and origin for the third one;
* - repeat;
* - split each remaining element from @collect into 2 ranges of
* order=N-1,
* - repeat.
*/
collect.order = MAX_ORDER;
for (int i = MAX_ORDER; i >= 0; i--) {
if (held_back[i].shadow)
smallstack_push(&collect, held_back[i].shadow);
if (held_back[i].origin)
smallstack_push(&collect, held_back[i].origin);
held_back[i].shadow = NULL;
held_back[i].origin = NULL;
do_collection();
collect_split();
}
}
void __init kmsan_init_runtime(void)
{
/* Assuming current is init_task */
kmsan_internal_task_create(current);
kmsan_memblock_discard();
pr_info("Starting KernelMemorySanitizer\n");
pr_info("ATTENTION: KMSAN is a debugging tool! Do not use it on production machines!\n");
kmsan_enabled = true;
}
| linux-master | mm/kmsan/init.c |
// SPDX-License-Identifier: GPL-2.0
/*
* KMSAN runtime library.
*
* Copyright (C) 2017-2022 Google LLC
* Author: Alexander Potapenko <[email protected]>
*
*/
#include <asm/page.h>
#include <linux/compiler.h>
#include <linux/export.h>
#include <linux/highmem.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/kmsan_types.h>
#include <linux/memory.h>
#include <linux/mm.h>
#include <linux/mm_types.h>
#include <linux/mmzone.h>
#include <linux/percpu-defs.h>
#include <linux/preempt.h>
#include <linux/slab.h>
#include <linux/stackdepot.h>
#include <linux/stacktrace.h>
#include <linux/types.h>
#include <linux/vmalloc.h>
#include "../slab.h"
#include "kmsan.h"
bool kmsan_enabled __read_mostly;
/*
* Per-CPU KMSAN context to be used in interrupts, where current->kmsan is
* unavaliable.
*/
DEFINE_PER_CPU(struct kmsan_ctx, kmsan_percpu_ctx);
void kmsan_internal_task_create(struct task_struct *task)
{
struct kmsan_ctx *ctx = &task->kmsan_ctx;
struct thread_info *info = current_thread_info();
__memset(ctx, 0, sizeof(*ctx));
ctx->allow_reporting = true;
kmsan_internal_unpoison_memory(info, sizeof(*info), false);
}
void kmsan_internal_poison_memory(void *address, size_t size, gfp_t flags,
unsigned int poison_flags)
{
u32 extra_bits =
kmsan_extra_bits(/*depth*/ 0, poison_flags & KMSAN_POISON_FREE);
bool checked = poison_flags & KMSAN_POISON_CHECK;
depot_stack_handle_t handle;
handle = kmsan_save_stack_with_flags(flags, extra_bits);
kmsan_internal_set_shadow_origin(address, size, -1, handle, checked);
}
void kmsan_internal_unpoison_memory(void *address, size_t size, bool checked)
{
kmsan_internal_set_shadow_origin(address, size, 0, 0, checked);
}
depot_stack_handle_t kmsan_save_stack_with_flags(gfp_t flags,
unsigned int extra)
{
unsigned long entries[KMSAN_STACK_DEPTH];
unsigned int nr_entries;
depot_stack_handle_t handle;
nr_entries = stack_trace_save(entries, KMSAN_STACK_DEPTH, 0);
/* Don't sleep. */
flags &= ~(__GFP_DIRECT_RECLAIM | __GFP_KSWAPD_RECLAIM);
handle = __stack_depot_save(entries, nr_entries, flags, true);
return stack_depot_set_extra_bits(handle, extra);
}
/* Copy the metadata following the memmove() behavior. */
void kmsan_internal_memmove_metadata(void *dst, void *src, size_t n)
{
depot_stack_handle_t old_origin = 0, new_origin = 0;
int src_slots, dst_slots, i, iter, step, skip_bits;
depot_stack_handle_t *origin_src, *origin_dst;
void *shadow_src, *shadow_dst;
u32 *align_shadow_src, shadow;
bool backwards;
shadow_dst = kmsan_get_metadata(dst, KMSAN_META_SHADOW);
if (!shadow_dst)
return;
KMSAN_WARN_ON(!kmsan_metadata_is_contiguous(dst, n));
shadow_src = kmsan_get_metadata(src, KMSAN_META_SHADOW);
if (!shadow_src) {
/*
* @src is untracked: zero out destination shadow, ignore the
* origins, we're done.
*/
__memset(shadow_dst, 0, n);
return;
}
KMSAN_WARN_ON(!kmsan_metadata_is_contiguous(src, n));
__memmove(shadow_dst, shadow_src, n);
origin_dst = kmsan_get_metadata(dst, KMSAN_META_ORIGIN);
origin_src = kmsan_get_metadata(src, KMSAN_META_ORIGIN);
KMSAN_WARN_ON(!origin_dst || !origin_src);
src_slots = (ALIGN((u64)src + n, KMSAN_ORIGIN_SIZE) -
ALIGN_DOWN((u64)src, KMSAN_ORIGIN_SIZE)) /
KMSAN_ORIGIN_SIZE;
dst_slots = (ALIGN((u64)dst + n, KMSAN_ORIGIN_SIZE) -
ALIGN_DOWN((u64)dst, KMSAN_ORIGIN_SIZE)) /
KMSAN_ORIGIN_SIZE;
KMSAN_WARN_ON((src_slots < 1) || (dst_slots < 1));
KMSAN_WARN_ON((src_slots - dst_slots > 1) ||
(dst_slots - src_slots < -1));
backwards = dst > src;
i = backwards ? min(src_slots, dst_slots) - 1 : 0;
iter = backwards ? -1 : 1;
align_shadow_src =
(u32 *)ALIGN_DOWN((u64)shadow_src, KMSAN_ORIGIN_SIZE);
for (step = 0; step < min(src_slots, dst_slots); step++, i += iter) {
KMSAN_WARN_ON(i < 0);
shadow = align_shadow_src[i];
if (i == 0) {
/*
* If @src isn't aligned on KMSAN_ORIGIN_SIZE, don't
* look at the first @src % KMSAN_ORIGIN_SIZE bytes
* of the first shadow slot.
*/
skip_bits = ((u64)src % KMSAN_ORIGIN_SIZE) * 8;
shadow = (shadow >> skip_bits) << skip_bits;
}
if (i == src_slots - 1) {
/*
* If @src + n isn't aligned on
* KMSAN_ORIGIN_SIZE, don't look at the last
* (@src + n) % KMSAN_ORIGIN_SIZE bytes of the
* last shadow slot.
*/
skip_bits = (((u64)src + n) % KMSAN_ORIGIN_SIZE) * 8;
shadow = (shadow << skip_bits) >> skip_bits;
}
/*
* Overwrite the origin only if the corresponding
* shadow is nonempty.
*/
if (origin_src[i] && (origin_src[i] != old_origin) && shadow) {
old_origin = origin_src[i];
new_origin = kmsan_internal_chain_origin(old_origin);
/*
* kmsan_internal_chain_origin() may return
* NULL, but we don't want to lose the previous
* origin value.
*/
if (!new_origin)
new_origin = old_origin;
}
if (shadow)
origin_dst[i] = new_origin;
else
origin_dst[i] = 0;
}
/*
* If dst_slots is greater than src_slots (i.e.
* dst_slots == src_slots + 1), there is an extra origin slot at the
* beginning or end of the destination buffer, for which we take the
* origin from the previous slot.
* This is only done if the part of the source shadow corresponding to
* slot is non-zero.
*
* E.g. if we copy 8 aligned bytes that are marked as uninitialized
* and have origins o111 and o222, to an unaligned buffer with offset 1,
* these two origins are copied to three origin slots, so one of then
* needs to be duplicated, depending on the copy direction (@backwards)
*
* src shadow: |uuuu|uuuu|....|
* src origin: |o111|o222|....|
*
* backwards = 0:
* dst shadow: |.uuu|uuuu|u...|
* dst origin: |....|o111|o222| - fill the empty slot with o111
* backwards = 1:
* dst shadow: |.uuu|uuuu|u...|
* dst origin: |o111|o222|....| - fill the empty slot with o222
*/
if (src_slots < dst_slots) {
if (backwards) {
shadow = align_shadow_src[src_slots - 1];
skip_bits = (((u64)dst + n) % KMSAN_ORIGIN_SIZE) * 8;
shadow = (shadow << skip_bits) >> skip_bits;
if (shadow)
/* src_slots > 0, therefore dst_slots is at least 2 */
origin_dst[dst_slots - 1] =
origin_dst[dst_slots - 2];
} else {
shadow = align_shadow_src[0];
skip_bits = ((u64)dst % KMSAN_ORIGIN_SIZE) * 8;
shadow = (shadow >> skip_bits) << skip_bits;
if (shadow)
origin_dst[0] = origin_dst[1];
}
}
}
depot_stack_handle_t kmsan_internal_chain_origin(depot_stack_handle_t id)
{
unsigned long entries[3];
u32 extra_bits;
int depth;
bool uaf;
depot_stack_handle_t handle;
if (!id)
return id;
/*
* Make sure we have enough spare bits in @id to hold the UAF bit and
* the chain depth.
*/
BUILD_BUG_ON(
(1 << STACK_DEPOT_EXTRA_BITS) <= (KMSAN_MAX_ORIGIN_DEPTH << 1));
extra_bits = stack_depot_get_extra_bits(id);
depth = kmsan_depth_from_eb(extra_bits);
uaf = kmsan_uaf_from_eb(extra_bits);
/*
* Stop chaining origins once the depth reached KMSAN_MAX_ORIGIN_DEPTH.
* This mostly happens in the case structures with uninitialized padding
* are copied around many times. Origin chains for such structures are
* usually periodic, and it does not make sense to fully store them.
*/
if (depth == KMSAN_MAX_ORIGIN_DEPTH)
return id;
depth++;
extra_bits = kmsan_extra_bits(depth, uaf);
entries[0] = KMSAN_CHAIN_MAGIC_ORIGIN;
entries[1] = kmsan_save_stack_with_flags(__GFP_HIGH, 0);
entries[2] = id;
/*
* @entries is a local var in non-instrumented code, so KMSAN does not
* know it is initialized. Explicitly unpoison it to avoid false
* positives when __stack_depot_save() passes it to instrumented code.
*/
kmsan_internal_unpoison_memory(entries, sizeof(entries), false);
handle = __stack_depot_save(entries, ARRAY_SIZE(entries), __GFP_HIGH,
true);
return stack_depot_set_extra_bits(handle, extra_bits);
}
void kmsan_internal_set_shadow_origin(void *addr, size_t size, int b,
u32 origin, bool checked)
{
u64 address = (u64)addr;
void *shadow_start;
u32 *origin_start;
size_t pad = 0;
KMSAN_WARN_ON(!kmsan_metadata_is_contiguous(addr, size));
shadow_start = kmsan_get_metadata(addr, KMSAN_META_SHADOW);
if (!shadow_start) {
/*
* kmsan_metadata_is_contiguous() is true, so either all shadow
* and origin pages are NULL, or all are non-NULL.
*/
if (checked) {
pr_err("%s: not memsetting %ld bytes starting at %px, because the shadow is NULL\n",
__func__, size, addr);
KMSAN_WARN_ON(true);
}
return;
}
__memset(shadow_start, b, size);
if (!IS_ALIGNED(address, KMSAN_ORIGIN_SIZE)) {
pad = address % KMSAN_ORIGIN_SIZE;
address -= pad;
size += pad;
}
size = ALIGN(size, KMSAN_ORIGIN_SIZE);
origin_start =
(u32 *)kmsan_get_metadata((void *)address, KMSAN_META_ORIGIN);
for (int i = 0; i < size / KMSAN_ORIGIN_SIZE; i++)
origin_start[i] = origin;
}
struct page *kmsan_vmalloc_to_page_or_null(void *vaddr)
{
struct page *page;
if (!kmsan_internal_is_vmalloc_addr(vaddr) &&
!kmsan_internal_is_module_addr(vaddr))
return NULL;
page = vmalloc_to_page(vaddr);
if (pfn_valid(page_to_pfn(page)))
return page;
else
return NULL;
}
void kmsan_internal_check_memory(void *addr, size_t size, const void *user_addr,
int reason)
{
depot_stack_handle_t cur_origin = 0, new_origin = 0;
unsigned long addr64 = (unsigned long)addr;
depot_stack_handle_t *origin = NULL;
unsigned char *shadow = NULL;
int cur_off_start = -1;
int chunk_size;
size_t pos = 0;
if (!size)
return;
KMSAN_WARN_ON(!kmsan_metadata_is_contiguous(addr, size));
while (pos < size) {
chunk_size = min(size - pos,
PAGE_SIZE - ((addr64 + pos) % PAGE_SIZE));
shadow = kmsan_get_metadata((void *)(addr64 + pos),
KMSAN_META_SHADOW);
if (!shadow) {
/*
* This page is untracked. If there were uninitialized
* bytes before, report them.
*/
if (cur_origin) {
kmsan_enter_runtime();
kmsan_report(cur_origin, addr, size,
cur_off_start, pos - 1, user_addr,
reason);
kmsan_leave_runtime();
}
cur_origin = 0;
cur_off_start = -1;
pos += chunk_size;
continue;
}
for (int i = 0; i < chunk_size; i++) {
if (!shadow[i]) {
/*
* This byte is unpoisoned. If there were
* poisoned bytes before, report them.
*/
if (cur_origin) {
kmsan_enter_runtime();
kmsan_report(cur_origin, addr, size,
cur_off_start, pos + i - 1,
user_addr, reason);
kmsan_leave_runtime();
}
cur_origin = 0;
cur_off_start = -1;
continue;
}
origin = kmsan_get_metadata((void *)(addr64 + pos + i),
KMSAN_META_ORIGIN);
KMSAN_WARN_ON(!origin);
new_origin = *origin;
/*
* Encountered new origin - report the previous
* uninitialized range.
*/
if (cur_origin != new_origin) {
if (cur_origin) {
kmsan_enter_runtime();
kmsan_report(cur_origin, addr, size,
cur_off_start, pos + i - 1,
user_addr, reason);
kmsan_leave_runtime();
}
cur_origin = new_origin;
cur_off_start = pos + i;
}
}
pos += chunk_size;
}
KMSAN_WARN_ON(pos != size);
if (cur_origin) {
kmsan_enter_runtime();
kmsan_report(cur_origin, addr, size, cur_off_start, pos - 1,
user_addr, reason);
kmsan_leave_runtime();
}
}
bool kmsan_metadata_is_contiguous(void *addr, size_t size)
{
char *cur_shadow = NULL, *next_shadow = NULL, *cur_origin = NULL,
*next_origin = NULL;
u64 cur_addr = (u64)addr, next_addr = cur_addr + PAGE_SIZE;
depot_stack_handle_t *origin_p;
bool all_untracked = false;
if (!size)
return true;
/* The whole range belongs to the same page. */
if (ALIGN_DOWN(cur_addr + size - 1, PAGE_SIZE) ==
ALIGN_DOWN(cur_addr, PAGE_SIZE))
return true;
cur_shadow = kmsan_get_metadata((void *)cur_addr, /*is_origin*/ false);
if (!cur_shadow)
all_untracked = true;
cur_origin = kmsan_get_metadata((void *)cur_addr, /*is_origin*/ true);
if (all_untracked && cur_origin)
goto report;
for (; next_addr < (u64)addr + size;
cur_addr = next_addr, cur_shadow = next_shadow,
cur_origin = next_origin, next_addr += PAGE_SIZE) {
next_shadow = kmsan_get_metadata((void *)next_addr, false);
next_origin = kmsan_get_metadata((void *)next_addr, true);
if (all_untracked) {
if (next_shadow || next_origin)
goto report;
if (!next_shadow && !next_origin)
continue;
}
if (((u64)cur_shadow == ((u64)next_shadow - PAGE_SIZE)) &&
((u64)cur_origin == ((u64)next_origin - PAGE_SIZE)))
continue;
goto report;
}
return true;
report:
pr_err("%s: attempting to access two shadow page ranges.\n", __func__);
pr_err("Access of size %ld at %px.\n", size, addr);
pr_err("Addresses belonging to different ranges: %px and %px\n",
(void *)cur_addr, (void *)next_addr);
pr_err("page[0].shadow: %px, page[1].shadow: %px\n", cur_shadow,
next_shadow);
pr_err("page[0].origin: %px, page[1].origin: %px\n", cur_origin,
next_origin);
origin_p = kmsan_get_metadata(addr, KMSAN_META_ORIGIN);
if (origin_p) {
pr_err("Origin: %08x\n", *origin_p);
kmsan_print_origin(*origin_p);
} else {
pr_err("Origin: unavailable\n");
}
return false;
}
| linux-master | mm/kmsan/core.c |
// SPDX-License-Identifier: GPL-2.0
/*
* KMSAN hooks for kernel subsystems.
*
* These functions handle creation of KMSAN metadata for memory allocations.
*
* Copyright (C) 2018-2022 Google LLC
* Author: Alexander Potapenko <[email protected]>
*
*/
#include <linux/cacheflush.h>
#include <linux/dma-direction.h>
#include <linux/gfp.h>
#include <linux/kmsan.h>
#include <linux/mm.h>
#include <linux/mm_types.h>
#include <linux/scatterlist.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/usb.h>
#include "../internal.h"
#include "../slab.h"
#include "kmsan.h"
/*
* Instrumented functions shouldn't be called under
* kmsan_enter_runtime()/kmsan_leave_runtime(), because this will lead to
* skipping effects of functions like memset() inside instrumented code.
*/
void kmsan_task_create(struct task_struct *task)
{
kmsan_enter_runtime();
kmsan_internal_task_create(task);
kmsan_leave_runtime();
}
void kmsan_task_exit(struct task_struct *task)
{
struct kmsan_ctx *ctx = &task->kmsan_ctx;
if (!kmsan_enabled || kmsan_in_runtime())
return;
ctx->allow_reporting = false;
}
void kmsan_slab_alloc(struct kmem_cache *s, void *object, gfp_t flags)
{
if (unlikely(object == NULL))
return;
if (!kmsan_enabled || kmsan_in_runtime())
return;
/*
* There's a ctor or this is an RCU cache - do nothing. The memory
* status hasn't changed since last use.
*/
if (s->ctor || (s->flags & SLAB_TYPESAFE_BY_RCU))
return;
kmsan_enter_runtime();
if (flags & __GFP_ZERO)
kmsan_internal_unpoison_memory(object, s->object_size,
KMSAN_POISON_CHECK);
else
kmsan_internal_poison_memory(object, s->object_size, flags,
KMSAN_POISON_CHECK);
kmsan_leave_runtime();
}
void kmsan_slab_free(struct kmem_cache *s, void *object)
{
if (!kmsan_enabled || kmsan_in_runtime())
return;
/* RCU slabs could be legally used after free within the RCU period */
if (unlikely(s->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)))
return;
/*
* If there's a constructor, freed memory must remain in the same state
* until the next allocation. We cannot save its state to detect
* use-after-free bugs, instead we just keep it unpoisoned.
*/
if (s->ctor)
return;
kmsan_enter_runtime();
kmsan_internal_poison_memory(object, s->object_size, GFP_KERNEL,
KMSAN_POISON_CHECK | KMSAN_POISON_FREE);
kmsan_leave_runtime();
}
void kmsan_kmalloc_large(const void *ptr, size_t size, gfp_t flags)
{
if (unlikely(ptr == NULL))
return;
if (!kmsan_enabled || kmsan_in_runtime())
return;
kmsan_enter_runtime();
if (flags & __GFP_ZERO)
kmsan_internal_unpoison_memory((void *)ptr, size,
/*checked*/ true);
else
kmsan_internal_poison_memory((void *)ptr, size, flags,
KMSAN_POISON_CHECK);
kmsan_leave_runtime();
}
void kmsan_kfree_large(const void *ptr)
{
struct page *page;
if (!kmsan_enabled || kmsan_in_runtime())
return;
kmsan_enter_runtime();
page = virt_to_head_page((void *)ptr);
KMSAN_WARN_ON(ptr != page_address(page));
kmsan_internal_poison_memory((void *)ptr,
page_size(page),
GFP_KERNEL,
KMSAN_POISON_CHECK | KMSAN_POISON_FREE);
kmsan_leave_runtime();
}
static unsigned long vmalloc_shadow(unsigned long addr)
{
return (unsigned long)kmsan_get_metadata((void *)addr,
KMSAN_META_SHADOW);
}
static unsigned long vmalloc_origin(unsigned long addr)
{
return (unsigned long)kmsan_get_metadata((void *)addr,
KMSAN_META_ORIGIN);
}
void kmsan_vunmap_range_noflush(unsigned long start, unsigned long end)
{
__vunmap_range_noflush(vmalloc_shadow(start), vmalloc_shadow(end));
__vunmap_range_noflush(vmalloc_origin(start), vmalloc_origin(end));
flush_cache_vmap(vmalloc_shadow(start), vmalloc_shadow(end));
flush_cache_vmap(vmalloc_origin(start), vmalloc_origin(end));
}
/*
* This function creates new shadow/origin pages for the physical pages mapped
* into the virtual memory. If those physical pages already had shadow/origin,
* those are ignored.
*/
int kmsan_ioremap_page_range(unsigned long start, unsigned long end,
phys_addr_t phys_addr, pgprot_t prot,
unsigned int page_shift)
{
gfp_t gfp_mask = GFP_KERNEL | __GFP_ZERO;
struct page *shadow, *origin;
unsigned long off = 0;
int nr, err = 0, clean = 0, mapped;
if (!kmsan_enabled || kmsan_in_runtime())
return 0;
nr = (end - start) / PAGE_SIZE;
kmsan_enter_runtime();
for (int i = 0; i < nr; i++, off += PAGE_SIZE, clean = i) {
shadow = alloc_pages(gfp_mask, 1);
origin = alloc_pages(gfp_mask, 1);
if (!shadow || !origin) {
err = -ENOMEM;
goto ret;
}
mapped = __vmap_pages_range_noflush(
vmalloc_shadow(start + off),
vmalloc_shadow(start + off + PAGE_SIZE), prot, &shadow,
PAGE_SHIFT);
if (mapped) {
err = mapped;
goto ret;
}
shadow = NULL;
mapped = __vmap_pages_range_noflush(
vmalloc_origin(start + off),
vmalloc_origin(start + off + PAGE_SIZE), prot, &origin,
PAGE_SHIFT);
if (mapped) {
__vunmap_range_noflush(
vmalloc_shadow(start + off),
vmalloc_shadow(start + off + PAGE_SIZE));
err = mapped;
goto ret;
}
origin = NULL;
}
/* Page mapping loop finished normally, nothing to clean up. */
clean = 0;
ret:
if (clean > 0) {
/*
* Something went wrong. Clean up shadow/origin pages allocated
* on the last loop iteration, then delete mappings created
* during the previous iterations.
*/
if (shadow)
__free_pages(shadow, 1);
if (origin)
__free_pages(origin, 1);
__vunmap_range_noflush(
vmalloc_shadow(start),
vmalloc_shadow(start + clean * PAGE_SIZE));
__vunmap_range_noflush(
vmalloc_origin(start),
vmalloc_origin(start + clean * PAGE_SIZE));
}
flush_cache_vmap(vmalloc_shadow(start), vmalloc_shadow(end));
flush_cache_vmap(vmalloc_origin(start), vmalloc_origin(end));
kmsan_leave_runtime();
return err;
}
void kmsan_iounmap_page_range(unsigned long start, unsigned long end)
{
unsigned long v_shadow, v_origin;
struct page *shadow, *origin;
int nr;
if (!kmsan_enabled || kmsan_in_runtime())
return;
nr = (end - start) / PAGE_SIZE;
kmsan_enter_runtime();
v_shadow = (unsigned long)vmalloc_shadow(start);
v_origin = (unsigned long)vmalloc_origin(start);
for (int i = 0; i < nr;
i++, v_shadow += PAGE_SIZE, v_origin += PAGE_SIZE) {
shadow = kmsan_vmalloc_to_page_or_null((void *)v_shadow);
origin = kmsan_vmalloc_to_page_or_null((void *)v_origin);
__vunmap_range_noflush(v_shadow, vmalloc_shadow(end));
__vunmap_range_noflush(v_origin, vmalloc_origin(end));
if (shadow)
__free_pages(shadow, 1);
if (origin)
__free_pages(origin, 1);
}
flush_cache_vmap(vmalloc_shadow(start), vmalloc_shadow(end));
flush_cache_vmap(vmalloc_origin(start), vmalloc_origin(end));
kmsan_leave_runtime();
}
void kmsan_copy_to_user(void __user *to, const void *from, size_t to_copy,
size_t left)
{
unsigned long ua_flags;
if (!kmsan_enabled || kmsan_in_runtime())
return;
/*
* At this point we've copied the memory already. It's hard to check it
* before copying, as the size of actually copied buffer is unknown.
*/
/* copy_to_user() may copy zero bytes. No need to check. */
if (!to_copy)
return;
/* Or maybe copy_to_user() failed to copy anything. */
if (to_copy <= left)
return;
ua_flags = user_access_save();
if ((u64)to < TASK_SIZE) {
/* This is a user memory access, check it. */
kmsan_internal_check_memory((void *)from, to_copy - left, to,
REASON_COPY_TO_USER);
} else {
/* Otherwise this is a kernel memory access. This happens when a
* compat syscall passes an argument allocated on the kernel
* stack to a real syscall.
* Don't check anything, just copy the shadow of the copied
* bytes.
*/
kmsan_internal_memmove_metadata((void *)to, (void *)from,
to_copy - left);
}
user_access_restore(ua_flags);
}
EXPORT_SYMBOL(kmsan_copy_to_user);
/* Helper function to check an URB. */
void kmsan_handle_urb(const struct urb *urb, bool is_out)
{
if (!urb)
return;
if (is_out)
kmsan_internal_check_memory(urb->transfer_buffer,
urb->transfer_buffer_length,
/*user_addr*/ 0, REASON_SUBMIT_URB);
else
kmsan_internal_unpoison_memory(urb->transfer_buffer,
urb->transfer_buffer_length,
/*checked*/ false);
}
EXPORT_SYMBOL_GPL(kmsan_handle_urb);
static void kmsan_handle_dma_page(const void *addr, size_t size,
enum dma_data_direction dir)
{
switch (dir) {
case DMA_BIDIRECTIONAL:
kmsan_internal_check_memory((void *)addr, size, /*user_addr*/ 0,
REASON_ANY);
kmsan_internal_unpoison_memory((void *)addr, size,
/*checked*/ false);
break;
case DMA_TO_DEVICE:
kmsan_internal_check_memory((void *)addr, size, /*user_addr*/ 0,
REASON_ANY);
break;
case DMA_FROM_DEVICE:
kmsan_internal_unpoison_memory((void *)addr, size,
/*checked*/ false);
break;
case DMA_NONE:
break;
}
}
/* Helper function to handle DMA data transfers. */
void kmsan_handle_dma(struct page *page, size_t offset, size_t size,
enum dma_data_direction dir)
{
u64 page_offset, to_go, addr;
if (PageHighMem(page))
return;
addr = (u64)page_address(page) + offset;
/*
* The kernel may occasionally give us adjacent DMA pages not belonging
* to the same allocation. Process them separately to avoid triggering
* internal KMSAN checks.
*/
while (size > 0) {
page_offset = offset_in_page(addr);
to_go = min(PAGE_SIZE - page_offset, (u64)size);
kmsan_handle_dma_page((void *)addr, to_go, dir);
addr += to_go;
size -= to_go;
}
}
void kmsan_handle_dma_sg(struct scatterlist *sg, int nents,
enum dma_data_direction dir)
{
struct scatterlist *item;
int i;
for_each_sg(sg, item, nents, i)
kmsan_handle_dma(sg_page(item), item->offset, item->length,
dir);
}
/* Functions from kmsan-checks.h follow. */
void kmsan_poison_memory(const void *address, size_t size, gfp_t flags)
{
if (!kmsan_enabled || kmsan_in_runtime())
return;
kmsan_enter_runtime();
/* The users may want to poison/unpoison random memory. */
kmsan_internal_poison_memory((void *)address, size, flags,
KMSAN_POISON_NOCHECK);
kmsan_leave_runtime();
}
EXPORT_SYMBOL(kmsan_poison_memory);
void kmsan_unpoison_memory(const void *address, size_t size)
{
unsigned long ua_flags;
if (!kmsan_enabled || kmsan_in_runtime())
return;
ua_flags = user_access_save();
kmsan_enter_runtime();
/* The users may want to poison/unpoison random memory. */
kmsan_internal_unpoison_memory((void *)address, size,
KMSAN_POISON_NOCHECK);
kmsan_leave_runtime();
user_access_restore(ua_flags);
}
EXPORT_SYMBOL(kmsan_unpoison_memory);
/*
* Version of kmsan_unpoison_memory() that can be called from within the KMSAN
* runtime.
*
* Non-instrumented IRQ entry functions receive struct pt_regs from assembly
* code. Those regs need to be unpoisoned, otherwise using them will result in
* false positives.
* Using kmsan_unpoison_memory() is not an option in entry code, because the
* return value of in_task() is inconsistent - as a result, certain calls to
* kmsan_unpoison_memory() are ignored. kmsan_unpoison_entry_regs() ensures that
* the registers are unpoisoned even if kmsan_in_runtime() is true in the early
* entry code.
*/
void kmsan_unpoison_entry_regs(const struct pt_regs *regs)
{
unsigned long ua_flags;
if (!kmsan_enabled)
return;
ua_flags = user_access_save();
kmsan_internal_unpoison_memory((void *)regs, sizeof(*regs),
KMSAN_POISON_NOCHECK);
user_access_restore(ua_flags);
}
void kmsan_check_memory(const void *addr, size_t size)
{
if (!kmsan_enabled)
return;
return kmsan_internal_check_memory((void *)addr, size, /*user_addr*/ 0,
REASON_ANY);
}
EXPORT_SYMBOL(kmsan_check_memory);
| linux-master | mm/kmsan/hooks.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Test cases for KMSAN.
* For each test case checks the presence (or absence) of generated reports.
* Relies on 'console' tracepoint to capture reports as they appear in the
* kernel log.
*
* Copyright (C) 2021-2022, Google LLC.
* Author: Alexander Potapenko <[email protected]>
*
*/
#include <kunit/test.h>
#include "kmsan.h"
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/kmsan.h>
#include <linux/mm.h>
#include <linux/random.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/tracepoint.h>
#include <linux/vmalloc.h>
#include <trace/events/printk.h>
static DEFINE_PER_CPU(int, per_cpu_var);
/* Report as observed from console. */
static struct {
spinlock_t lock;
bool available;
bool ignore; /* Stop console output collection. */
char header[256];
} observed = {
.lock = __SPIN_LOCK_UNLOCKED(observed.lock),
};
/* Probe for console output: obtains observed lines of interest. */
static void probe_console(void *ignore, const char *buf, size_t len)
{
unsigned long flags;
if (observed.ignore)
return;
spin_lock_irqsave(&observed.lock, flags);
if (strnstr(buf, "BUG: KMSAN: ", len)) {
/*
* KMSAN report and related to the test.
*
* The provided @buf is not NUL-terminated; copy no more than
* @len bytes and let strscpy() add the missing NUL-terminator.
*/
strscpy(observed.header, buf,
min(len + 1, sizeof(observed.header)));
WRITE_ONCE(observed.available, true);
observed.ignore = true;
}
spin_unlock_irqrestore(&observed.lock, flags);
}
/* Check if a report related to the test exists. */
static bool report_available(void)
{
return READ_ONCE(observed.available);
}
/* Information we expect in a report. */
struct expect_report {
const char *error_type; /* Error type. */
/*
* Kernel symbol from the error header, or NULL if no report is
* expected.
*/
const char *symbol;
};
/* Check observed report matches information in @r. */
static bool report_matches(const struct expect_report *r)
{
typeof(observed.header) expected_header;
unsigned long flags;
bool ret = false;
const char *end;
char *cur;
/* Doubled-checked locking. */
if (!report_available() || !r->symbol)
return (!report_available() && !r->symbol);
/* Generate expected report contents. */
/* Title */
cur = expected_header;
end = &expected_header[sizeof(expected_header) - 1];
cur += scnprintf(cur, end - cur, "BUG: KMSAN: %s", r->error_type);
scnprintf(cur, end - cur, " in %s", r->symbol);
/* The exact offset won't match, remove it; also strip module name. */
cur = strchr(expected_header, '+');
if (cur)
*cur = '\0';
spin_lock_irqsave(&observed.lock, flags);
if (!report_available())
goto out; /* A new report is being captured. */
/* Finally match expected output to what we actually observed. */
ret = strstr(observed.header, expected_header);
out:
spin_unlock_irqrestore(&observed.lock, flags);
return ret;
}
/* ===== Test cases ===== */
/* Prevent replacing branch with select in LLVM. */
static noinline void check_true(char *arg)
{
pr_info("%s is true\n", arg);
}
static noinline void check_false(char *arg)
{
pr_info("%s is false\n", arg);
}
#define USE(x) \
do { \
if (x) \
check_true(#x); \
else \
check_false(#x); \
} while (0)
#define EXPECTATION_ETYPE_FN(e, reason, fn) \
struct expect_report e = { \
.error_type = reason, \
.symbol = fn, \
}
#define EXPECTATION_NO_REPORT(e) EXPECTATION_ETYPE_FN(e, NULL, NULL)
#define EXPECTATION_UNINIT_VALUE_FN(e, fn) \
EXPECTATION_ETYPE_FN(e, "uninit-value", fn)
#define EXPECTATION_UNINIT_VALUE(e) EXPECTATION_UNINIT_VALUE_FN(e, __func__)
#define EXPECTATION_USE_AFTER_FREE(e) \
EXPECTATION_ETYPE_FN(e, "use-after-free", __func__)
/* Test case: ensure that kmalloc() returns uninitialized memory. */
static void test_uninit_kmalloc(struct kunit *test)
{
EXPECTATION_UNINIT_VALUE(expect);
int *ptr;
kunit_info(test, "uninitialized kmalloc test (UMR report)\n");
ptr = kmalloc(sizeof(*ptr), GFP_KERNEL);
USE(*ptr);
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
}
/*
* Test case: ensure that kmalloc'ed memory becomes initialized after memset().
*/
static void test_init_kmalloc(struct kunit *test)
{
EXPECTATION_NO_REPORT(expect);
int *ptr;
kunit_info(test, "initialized kmalloc test (no reports)\n");
ptr = kmalloc(sizeof(*ptr), GFP_KERNEL);
memset(ptr, 0, sizeof(*ptr));
USE(*ptr);
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
}
/* Test case: ensure that kzalloc() returns initialized memory. */
static void test_init_kzalloc(struct kunit *test)
{
EXPECTATION_NO_REPORT(expect);
int *ptr;
kunit_info(test, "initialized kzalloc test (no reports)\n");
ptr = kzalloc(sizeof(*ptr), GFP_KERNEL);
USE(*ptr);
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
}
/* Test case: ensure that local variables are uninitialized by default. */
static void test_uninit_stack_var(struct kunit *test)
{
EXPECTATION_UNINIT_VALUE(expect);
volatile int cond;
kunit_info(test, "uninitialized stack variable (UMR report)\n");
USE(cond);
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
}
/* Test case: ensure that local variables with initializers are initialized. */
static void test_init_stack_var(struct kunit *test)
{
EXPECTATION_NO_REPORT(expect);
volatile int cond = 1;
kunit_info(test, "initialized stack variable (no reports)\n");
USE(cond);
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
}
static noinline void two_param_fn_2(int arg1, int arg2)
{
USE(arg1);
USE(arg2);
}
static noinline void one_param_fn(int arg)
{
two_param_fn_2(arg, arg);
USE(arg);
}
static noinline void two_param_fn(int arg1, int arg2)
{
int init = 0;
one_param_fn(init);
USE(arg1);
USE(arg2);
}
static void test_params(struct kunit *test)
{
#ifdef CONFIG_KMSAN_CHECK_PARAM_RETVAL
/*
* With eager param/retval checking enabled, KMSAN will report an error
* before the call to two_param_fn().
*/
EXPECTATION_UNINIT_VALUE_FN(expect, "test_params");
#else
EXPECTATION_UNINIT_VALUE_FN(expect, "two_param_fn");
#endif
volatile int uninit, init = 1;
kunit_info(test,
"uninit passed through a function parameter (UMR report)\n");
two_param_fn(uninit, init);
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
}
static int signed_sum3(int a, int b, int c)
{
return a + b + c;
}
/*
* Test case: ensure that uninitialized values are tracked through function
* arguments.
*/
static void test_uninit_multiple_params(struct kunit *test)
{
EXPECTATION_UNINIT_VALUE(expect);
volatile char b = 3, c;
volatile int a;
kunit_info(test, "uninitialized local passed to fn (UMR report)\n");
USE(signed_sum3(a, b, c));
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
}
/* Helper function to make an array uninitialized. */
static noinline void do_uninit_local_array(char *array, int start, int stop)
{
volatile char uninit;
for (int i = start; i < stop; i++)
array[i] = uninit;
}
/*
* Test case: ensure kmsan_check_memory() reports an error when checking
* uninitialized memory.
*/
static void test_uninit_kmsan_check_memory(struct kunit *test)
{
EXPECTATION_UNINIT_VALUE_FN(expect, "test_uninit_kmsan_check_memory");
volatile char local_array[8];
kunit_info(
test,
"kmsan_check_memory() called on uninit local (UMR report)\n");
do_uninit_local_array((char *)local_array, 5, 7);
kmsan_check_memory((char *)local_array, 8);
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
}
/*
* Test case: check that a virtual memory range created with vmap() from
* initialized pages is still considered as initialized.
*/
static void test_init_kmsan_vmap_vunmap(struct kunit *test)
{
EXPECTATION_NO_REPORT(expect);
const int npages = 2;
struct page **pages;
void *vbuf;
kunit_info(test, "pages initialized via vmap (no reports)\n");
pages = kmalloc_array(npages, sizeof(*pages), GFP_KERNEL);
for (int i = 0; i < npages; i++)
pages[i] = alloc_page(GFP_KERNEL);
vbuf = vmap(pages, npages, VM_MAP, PAGE_KERNEL);
memset(vbuf, 0xfe, npages * PAGE_SIZE);
for (int i = 0; i < npages; i++)
kmsan_check_memory(page_address(pages[i]), PAGE_SIZE);
if (vbuf)
vunmap(vbuf);
for (int i = 0; i < npages; i++) {
if (pages[i])
__free_page(pages[i]);
}
kfree(pages);
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
}
/*
* Test case: ensure that memset() can initialize a buffer allocated via
* vmalloc().
*/
static void test_init_vmalloc(struct kunit *test)
{
EXPECTATION_NO_REPORT(expect);
int npages = 8;
char *buf;
kunit_info(test, "vmalloc buffer can be initialized (no reports)\n");
buf = vmalloc(PAGE_SIZE * npages);
buf[0] = 1;
memset(buf, 0xfe, PAGE_SIZE * npages);
USE(buf[0]);
for (int i = 0; i < npages; i++)
kmsan_check_memory(&buf[PAGE_SIZE * i], PAGE_SIZE);
vfree(buf);
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
}
/* Test case: ensure that use-after-free reporting works. */
static void test_uaf(struct kunit *test)
{
EXPECTATION_USE_AFTER_FREE(expect);
volatile int value;
volatile int *var;
kunit_info(test, "use-after-free in kmalloc-ed buffer (UMR report)\n");
var = kmalloc(80, GFP_KERNEL);
var[3] = 0xfeedface;
kfree((int *)var);
/* Copy the invalid value before checking it. */
value = var[3];
USE(value);
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
}
/*
* Test case: ensure that uninitialized values are propagated through per-CPU
* memory.
*/
static void test_percpu_propagate(struct kunit *test)
{
EXPECTATION_UNINIT_VALUE(expect);
volatile int uninit, check;
kunit_info(test,
"uninit local stored to per_cpu memory (UMR report)\n");
this_cpu_write(per_cpu_var, uninit);
check = this_cpu_read(per_cpu_var);
USE(check);
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
}
/*
* Test case: ensure that passing uninitialized values to printk() leads to an
* error report.
*/
static void test_printk(struct kunit *test)
{
#ifdef CONFIG_KMSAN_CHECK_PARAM_RETVAL
/*
* With eager param/retval checking enabled, KMSAN will report an error
* before the call to pr_info().
*/
EXPECTATION_UNINIT_VALUE_FN(expect, "test_printk");
#else
EXPECTATION_UNINIT_VALUE_FN(expect, "number");
#endif
volatile int uninit;
kunit_info(test, "uninit local passed to pr_info() (UMR report)\n");
pr_info("%px contains %d\n", &uninit, uninit);
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
}
/*
* Prevent the compiler from optimizing @var away. Without this, Clang may
* notice that @var is uninitialized and drop memcpy() calls that use it.
*
* There is OPTIMIZER_HIDE_VAR() in linux/compier.h that we cannot use here,
* because it is implemented as inline assembly receiving @var as a parameter
* and will enforce a KMSAN check. Same is true for e.g. barrier_data(var).
*/
#define DO_NOT_OPTIMIZE(var) barrier()
/*
* Test case: ensure that memcpy() correctly copies initialized values.
* Also serves as a regression test to ensure DO_NOT_OPTIMIZE() does not cause
* extra checks.
*/
static void test_init_memcpy(struct kunit *test)
{
EXPECTATION_NO_REPORT(expect);
volatile int src;
volatile int dst = 0;
DO_NOT_OPTIMIZE(src);
src = 1;
kunit_info(
test,
"memcpy()ing aligned initialized src to aligned dst (no reports)\n");
memcpy((void *)&dst, (void *)&src, sizeof(src));
kmsan_check_memory((void *)&dst, sizeof(dst));
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
}
/*
* Test case: ensure that memcpy() correctly copies uninitialized values between
* aligned `src` and `dst`.
*/
static void test_memcpy_aligned_to_aligned(struct kunit *test)
{
EXPECTATION_UNINIT_VALUE_FN(expect, "test_memcpy_aligned_to_aligned");
volatile int uninit_src;
volatile int dst = 0;
kunit_info(
test,
"memcpy()ing aligned uninit src to aligned dst (UMR report)\n");
DO_NOT_OPTIMIZE(uninit_src);
memcpy((void *)&dst, (void *)&uninit_src, sizeof(uninit_src));
kmsan_check_memory((void *)&dst, sizeof(dst));
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
}
/*
* Test case: ensure that memcpy() correctly copies uninitialized values between
* aligned `src` and unaligned `dst`.
*
* Copying aligned 4-byte value to an unaligned one leads to touching two
* aligned 4-byte values. This test case checks that KMSAN correctly reports an
* error on the first of the two values.
*/
static void test_memcpy_aligned_to_unaligned(struct kunit *test)
{
EXPECTATION_UNINIT_VALUE_FN(expect, "test_memcpy_aligned_to_unaligned");
volatile int uninit_src;
volatile char dst[8] = { 0 };
kunit_info(
test,
"memcpy()ing aligned uninit src to unaligned dst (UMR report)\n");
DO_NOT_OPTIMIZE(uninit_src);
memcpy((void *)&dst[1], (void *)&uninit_src, sizeof(uninit_src));
kmsan_check_memory((void *)dst, 4);
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
}
/*
* Test case: ensure that memcpy() correctly copies uninitialized values between
* aligned `src` and unaligned `dst`.
*
* Copying aligned 4-byte value to an unaligned one leads to touching two
* aligned 4-byte values. This test case checks that KMSAN correctly reports an
* error on the second of the two values.
*/
static void test_memcpy_aligned_to_unaligned2(struct kunit *test)
{
EXPECTATION_UNINIT_VALUE_FN(expect,
"test_memcpy_aligned_to_unaligned2");
volatile int uninit_src;
volatile char dst[8] = { 0 };
kunit_info(
test,
"memcpy()ing aligned uninit src to unaligned dst - part 2 (UMR report)\n");
DO_NOT_OPTIMIZE(uninit_src);
memcpy((void *)&dst[1], (void *)&uninit_src, sizeof(uninit_src));
kmsan_check_memory((void *)&dst[4], sizeof(uninit_src));
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
}
/* Generate test cases for memset16(), memset32(), memset64(). */
#define DEFINE_TEST_MEMSETXX(size) \
static void test_memset##size(struct kunit *test) \
{ \
EXPECTATION_NO_REPORT(expect); \
volatile uint##size##_t uninit; \
\
kunit_info(test, \
"memset" #size "() should initialize memory\n"); \
DO_NOT_OPTIMIZE(uninit); \
memset##size((uint##size##_t *)&uninit, 0, 1); \
kmsan_check_memory((void *)&uninit, sizeof(uninit)); \
KUNIT_EXPECT_TRUE(test, report_matches(&expect)); \
}
DEFINE_TEST_MEMSETXX(16)
DEFINE_TEST_MEMSETXX(32)
DEFINE_TEST_MEMSETXX(64)
static noinline void fibonacci(int *array, int size, int start)
{
if (start < 2 || (start == size))
return;
array[start] = array[start - 1] + array[start - 2];
fibonacci(array, size, start + 1);
}
static void test_long_origin_chain(struct kunit *test)
{
EXPECTATION_UNINIT_VALUE_FN(expect, "test_long_origin_chain");
/* (KMSAN_MAX_ORIGIN_DEPTH * 2) recursive calls to fibonacci(). */
volatile int accum[KMSAN_MAX_ORIGIN_DEPTH * 2 + 2];
int last = ARRAY_SIZE(accum) - 1;
kunit_info(
test,
"origin chain exceeding KMSAN_MAX_ORIGIN_DEPTH (UMR report)\n");
/*
* We do not set accum[1] to 0, so the uninitializedness will be carried
* over to accum[2..last].
*/
accum[0] = 1;
fibonacci((int *)accum, ARRAY_SIZE(accum), 2);
kmsan_check_memory((void *)&accum[last], sizeof(int));
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
}
/*
* Test case: ensure that saving/restoring/printing stacks to/from stackdepot
* does not trigger errors.
*
* KMSAN uses stackdepot to store origin stack traces, that's why we do not
* instrument lib/stackdepot.c. Yet it must properly mark its outputs as
* initialized because other kernel features (e.g. netdev tracker) may also
* access stackdepot from instrumented code.
*/
static void test_stackdepot_roundtrip(struct kunit *test)
{
unsigned long src_entries[16], *dst_entries;
unsigned int src_nentries, dst_nentries;
EXPECTATION_NO_REPORT(expect);
depot_stack_handle_t handle;
kunit_info(test, "testing stackdepot roundtrip (no reports)\n");
src_nentries =
stack_trace_save(src_entries, ARRAY_SIZE(src_entries), 1);
handle = stack_depot_save(src_entries, src_nentries, GFP_KERNEL);
stack_depot_print(handle);
dst_nentries = stack_depot_fetch(handle, &dst_entries);
KUNIT_EXPECT_TRUE(test, src_nentries == dst_nentries);
kmsan_check_memory((void *)dst_entries,
sizeof(*dst_entries) * dst_nentries);
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
}
static struct kunit_case kmsan_test_cases[] = {
KUNIT_CASE(test_uninit_kmalloc),
KUNIT_CASE(test_init_kmalloc),
KUNIT_CASE(test_init_kzalloc),
KUNIT_CASE(test_uninit_stack_var),
KUNIT_CASE(test_init_stack_var),
KUNIT_CASE(test_params),
KUNIT_CASE(test_uninit_multiple_params),
KUNIT_CASE(test_uninit_kmsan_check_memory),
KUNIT_CASE(test_init_kmsan_vmap_vunmap),
KUNIT_CASE(test_init_vmalloc),
KUNIT_CASE(test_uaf),
KUNIT_CASE(test_percpu_propagate),
KUNIT_CASE(test_printk),
KUNIT_CASE(test_init_memcpy),
KUNIT_CASE(test_memcpy_aligned_to_aligned),
KUNIT_CASE(test_memcpy_aligned_to_unaligned),
KUNIT_CASE(test_memcpy_aligned_to_unaligned2),
KUNIT_CASE(test_memset16),
KUNIT_CASE(test_memset32),
KUNIT_CASE(test_memset64),
KUNIT_CASE(test_long_origin_chain),
KUNIT_CASE(test_stackdepot_roundtrip),
{},
};
/* ===== End test cases ===== */
static int test_init(struct kunit *test)
{
unsigned long flags;
spin_lock_irqsave(&observed.lock, flags);
observed.header[0] = '\0';
observed.ignore = false;
observed.available = false;
spin_unlock_irqrestore(&observed.lock, flags);
return 0;
}
static void test_exit(struct kunit *test)
{
}
static int kmsan_suite_init(struct kunit_suite *suite)
{
register_trace_console(probe_console, NULL);
return 0;
}
static void kmsan_suite_exit(struct kunit_suite *suite)
{
unregister_trace_console(probe_console, NULL);
tracepoint_synchronize_unregister();
}
static struct kunit_suite kmsan_test_suite = {
.name = "kmsan",
.test_cases = kmsan_test_cases,
.init = test_init,
.exit = test_exit,
.suite_init = kmsan_suite_init,
.suite_exit = kmsan_suite_exit,
};
kunit_test_suites(&kmsan_test_suite);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Alexander Potapenko <[email protected]>");
| linux-master | mm/kmsan/kmsan_test.c |
// SPDX-License-Identifier: GPL-2.0
/*
* This file contains software tag-based KASAN specific error reporting code.
*
* Copyright (c) 2014 Samsung Electronics Co., Ltd.
* Author: Andrey Ryabinin <[email protected]>
*
* Some code borrowed from https://github.com/xairy/kasan-prototype by
* Andrey Konovalov <[email protected]>
*/
#include <linux/bitops.h>
#include <linux/ftrace.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/printk.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/slab.h>
#include <linux/stackdepot.h>
#include <linux/stacktrace.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/kasan.h>
#include <linux/module.h>
#include <asm/sections.h>
#include "kasan.h"
#include "../slab.h"
const void *kasan_find_first_bad_addr(const void *addr, size_t size)
{
u8 tag = get_tag(addr);
void *p = kasan_reset_tag(addr);
void *end = p + size;
if (!addr_has_metadata(p))
return p;
while (p < end && tag == *(u8 *)kasan_mem_to_shadow(p))
p += KASAN_GRANULE_SIZE;
return p;
}
size_t kasan_get_alloc_size(void *object, struct kmem_cache *cache)
{
size_t size = 0;
u8 *shadow;
/*
* Skip the addr_has_metadata check, as this function only operates on
* slab memory, which must have metadata.
*/
/*
* The loop below returns 0 for freed objects, for which KASAN cannot
* calculate the allocation size based on the metadata.
*/
shadow = (u8 *)kasan_mem_to_shadow(object);
while (size < cache->object_size) {
if (*shadow != KASAN_TAG_INVALID)
size += KASAN_GRANULE_SIZE;
else
return size;
shadow++;
}
return cache->object_size;
}
void kasan_metadata_fetch_row(char *buffer, void *row)
{
memcpy(buffer, kasan_mem_to_shadow(row), META_BYTES_PER_ROW);
}
void kasan_print_tags(u8 addr_tag, const void *addr)
{
u8 *shadow = (u8 *)kasan_mem_to_shadow(addr);
pr_err("Pointer tag: [%02x], memory tag: [%02x]\n", addr_tag, *shadow);
}
#ifdef CONFIG_KASAN_STACK
void kasan_print_address_stack_frame(const void *addr)
{
if (WARN_ON(!object_is_on_stack(addr)))
return;
pr_err("The buggy address belongs to stack of task %s/%d\n",
current->comm, task_pid_nr(current));
}
#endif
| linux-master | mm/kasan/report_sw_tags.c |
// SPDX-License-Identifier: GPL-2.0
/*
* This file contains common KASAN code.
*
* Copyright (c) 2014 Samsung Electronics Co., Ltd.
* Author: Andrey Ryabinin <[email protected]>
*
* Some code borrowed from https://github.com/xairy/kasan-prototype by
* Andrey Konovalov <[email protected]>
*/
#include <linux/export.h>
#include <linux/init.h>
#include <linux/kasan.h>
#include <linux/kernel.h>
#include <linux/linkage.h>
#include <linux/memblock.h>
#include <linux/memory.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/printk.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/slab.h>
#include <linux/stacktrace.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/bug.h>
#include "kasan.h"
#include "../slab.h"
struct slab *kasan_addr_to_slab(const void *addr)
{
if (virt_addr_valid(addr))
return virt_to_slab(addr);
return NULL;
}
depot_stack_handle_t kasan_save_stack(gfp_t flags, bool can_alloc)
{
unsigned long entries[KASAN_STACK_DEPTH];
unsigned int nr_entries;
nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 0);
return __stack_depot_save(entries, nr_entries, flags, can_alloc);
}
void kasan_set_track(struct kasan_track *track, gfp_t flags)
{
track->pid = current->pid;
track->stack = kasan_save_stack(flags, true);
}
#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
void kasan_enable_current(void)
{
current->kasan_depth++;
}
EXPORT_SYMBOL(kasan_enable_current);
void kasan_disable_current(void)
{
current->kasan_depth--;
}
EXPORT_SYMBOL(kasan_disable_current);
#endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
void __kasan_unpoison_range(const void *address, size_t size)
{
kasan_unpoison(address, size, false);
}
#ifdef CONFIG_KASAN_STACK
/* Unpoison the entire stack for a task. */
void kasan_unpoison_task_stack(struct task_struct *task)
{
void *base = task_stack_page(task);
kasan_unpoison(base, THREAD_SIZE, false);
}
/* Unpoison the stack for the current task beyond a watermark sp value. */
asmlinkage void kasan_unpoison_task_stack_below(const void *watermark)
{
/*
* Calculate the task stack base address. Avoid using 'current'
* because this function is called by early resume code which hasn't
* yet set up the percpu register (%gs).
*/
void *base = (void *)((unsigned long)watermark & ~(THREAD_SIZE - 1));
kasan_unpoison(base, watermark - base, false);
}
#endif /* CONFIG_KASAN_STACK */
bool __kasan_unpoison_pages(struct page *page, unsigned int order, bool init)
{
u8 tag;
unsigned long i;
if (unlikely(PageHighMem(page)))
return false;
if (!kasan_sample_page_alloc(order))
return false;
tag = kasan_random_tag();
kasan_unpoison(set_tag(page_address(page), tag),
PAGE_SIZE << order, init);
for (i = 0; i < (1 << order); i++)
page_kasan_tag_set(page + i, tag);
return true;
}
void __kasan_poison_pages(struct page *page, unsigned int order, bool init)
{
if (likely(!PageHighMem(page)))
kasan_poison(page_address(page), PAGE_SIZE << order,
KASAN_PAGE_FREE, init);
}
void __kasan_poison_slab(struct slab *slab)
{
struct page *page = slab_page(slab);
unsigned long i;
for (i = 0; i < compound_nr(page); i++)
page_kasan_tag_reset(page + i);
kasan_poison(page_address(page), page_size(page),
KASAN_SLAB_REDZONE, false);
}
void __kasan_unpoison_object_data(struct kmem_cache *cache, void *object)
{
kasan_unpoison(object, cache->object_size, false);
}
void __kasan_poison_object_data(struct kmem_cache *cache, void *object)
{
kasan_poison(object, round_up(cache->object_size, KASAN_GRANULE_SIZE),
KASAN_SLAB_REDZONE, false);
}
/*
* This function assigns a tag to an object considering the following:
* 1. A cache might have a constructor, which might save a pointer to a slab
* object somewhere (e.g. in the object itself). We preassign a tag for
* each object in caches with constructors during slab creation and reuse
* the same tag each time a particular object is allocated.
* 2. A cache might be SLAB_TYPESAFE_BY_RCU, which means objects can be
* accessed after being freed. We preassign tags for objects in these
* caches as well.
* 3. For SLAB allocator we can't preassign tags randomly since the freelist
* is stored as an array of indexes instead of a linked list. Assign tags
* based on objects indexes, so that objects that are next to each other
* get different tags.
*/
static inline u8 assign_tag(struct kmem_cache *cache,
const void *object, bool init)
{
if (IS_ENABLED(CONFIG_KASAN_GENERIC))
return 0xff;
/*
* If the cache neither has a constructor nor has SLAB_TYPESAFE_BY_RCU
* set, assign a tag when the object is being allocated (init == false).
*/
if (!cache->ctor && !(cache->flags & SLAB_TYPESAFE_BY_RCU))
return init ? KASAN_TAG_KERNEL : kasan_random_tag();
/* For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU: */
#ifdef CONFIG_SLAB
/* For SLAB assign tags based on the object index in the freelist. */
return (u8)obj_to_index(cache, virt_to_slab(object), (void *)object);
#else
/*
* For SLUB assign a random tag during slab creation, otherwise reuse
* the already assigned tag.
*/
return init ? kasan_random_tag() : get_tag(object);
#endif
}
void * __must_check __kasan_init_slab_obj(struct kmem_cache *cache,
const void *object)
{
/* Initialize per-object metadata if it is present. */
if (kasan_requires_meta())
kasan_init_object_meta(cache, object);
/* Tag is ignored in set_tag() without CONFIG_KASAN_SW/HW_TAGS */
object = set_tag(object, assign_tag(cache, object, true));
return (void *)object;
}
static inline bool ____kasan_slab_free(struct kmem_cache *cache, void *object,
unsigned long ip, bool quarantine, bool init)
{
void *tagged_object;
if (!kasan_arch_is_ready())
return false;
tagged_object = object;
object = kasan_reset_tag(object);
if (is_kfence_address(object))
return false;
if (unlikely(nearest_obj(cache, virt_to_slab(object), object) !=
object)) {
kasan_report_invalid_free(tagged_object, ip, KASAN_REPORT_INVALID_FREE);
return true;
}
/* RCU slabs could be legally used after free within the RCU period */
if (unlikely(cache->flags & SLAB_TYPESAFE_BY_RCU))
return false;
if (!kasan_byte_accessible(tagged_object)) {
kasan_report_invalid_free(tagged_object, ip, KASAN_REPORT_DOUBLE_FREE);
return true;
}
kasan_poison(object, round_up(cache->object_size, KASAN_GRANULE_SIZE),
KASAN_SLAB_FREE, init);
if ((IS_ENABLED(CONFIG_KASAN_GENERIC) && !quarantine))
return false;
if (kasan_stack_collection_enabled())
kasan_save_free_info(cache, tagged_object);
return kasan_quarantine_put(cache, object);
}
bool __kasan_slab_free(struct kmem_cache *cache, void *object,
unsigned long ip, bool init)
{
return ____kasan_slab_free(cache, object, ip, true, init);
}
static inline bool ____kasan_kfree_large(void *ptr, unsigned long ip)
{
if (!kasan_arch_is_ready())
return false;
if (ptr != page_address(virt_to_head_page(ptr))) {
kasan_report_invalid_free(ptr, ip, KASAN_REPORT_INVALID_FREE);
return true;
}
if (!kasan_byte_accessible(ptr)) {
kasan_report_invalid_free(ptr, ip, KASAN_REPORT_DOUBLE_FREE);
return true;
}
/*
* The object will be poisoned by kasan_poison_pages() or
* kasan_slab_free_mempool().
*/
return false;
}
void __kasan_kfree_large(void *ptr, unsigned long ip)
{
____kasan_kfree_large(ptr, ip);
}
void __kasan_slab_free_mempool(void *ptr, unsigned long ip)
{
struct folio *folio;
folio = virt_to_folio(ptr);
/*
* Even though this function is only called for kmem_cache_alloc and
* kmalloc backed mempool allocations, those allocations can still be
* !PageSlab() when the size provided to kmalloc is larger than
* KMALLOC_MAX_SIZE, and kmalloc falls back onto page_alloc.
*/
if (unlikely(!folio_test_slab(folio))) {
if (____kasan_kfree_large(ptr, ip))
return;
kasan_poison(ptr, folio_size(folio), KASAN_PAGE_FREE, false);
} else {
struct slab *slab = folio_slab(folio);
____kasan_slab_free(slab->slab_cache, ptr, ip, false, false);
}
}
void * __must_check __kasan_slab_alloc(struct kmem_cache *cache,
void *object, gfp_t flags, bool init)
{
u8 tag;
void *tagged_object;
if (gfpflags_allow_blocking(flags))
kasan_quarantine_reduce();
if (unlikely(object == NULL))
return NULL;
if (is_kfence_address(object))
return (void *)object;
/*
* Generate and assign random tag for tag-based modes.
* Tag is ignored in set_tag() for the generic mode.
*/
tag = assign_tag(cache, object, false);
tagged_object = set_tag(object, tag);
/*
* Unpoison the whole object.
* For kmalloc() allocations, kasan_kmalloc() will do precise poisoning.
*/
kasan_unpoison(tagged_object, cache->object_size, init);
/* Save alloc info (if possible) for non-kmalloc() allocations. */
if (kasan_stack_collection_enabled() && !is_kmalloc_cache(cache))
kasan_save_alloc_info(cache, tagged_object, flags);
return tagged_object;
}
static inline void *____kasan_kmalloc(struct kmem_cache *cache,
const void *object, size_t size, gfp_t flags)
{
unsigned long redzone_start;
unsigned long redzone_end;
if (gfpflags_allow_blocking(flags))
kasan_quarantine_reduce();
if (unlikely(object == NULL))
return NULL;
if (is_kfence_address(kasan_reset_tag(object)))
return (void *)object;
/*
* The object has already been unpoisoned by kasan_slab_alloc() for
* kmalloc() or by kasan_krealloc() for krealloc().
*/
/*
* The redzone has byte-level precision for the generic mode.
* Partially poison the last object granule to cover the unaligned
* part of the redzone.
*/
if (IS_ENABLED(CONFIG_KASAN_GENERIC))
kasan_poison_last_granule((void *)object, size);
/* Poison the aligned part of the redzone. */
redzone_start = round_up((unsigned long)(object + size),
KASAN_GRANULE_SIZE);
redzone_end = round_up((unsigned long)(object + cache->object_size),
KASAN_GRANULE_SIZE);
kasan_poison((void *)redzone_start, redzone_end - redzone_start,
KASAN_SLAB_REDZONE, false);
/*
* Save alloc info (if possible) for kmalloc() allocations.
* This also rewrites the alloc info when called from kasan_krealloc().
*/
if (kasan_stack_collection_enabled() && is_kmalloc_cache(cache))
kasan_save_alloc_info(cache, (void *)object, flags);
/* Keep the tag that was set by kasan_slab_alloc(). */
return (void *)object;
}
void * __must_check __kasan_kmalloc(struct kmem_cache *cache, const void *object,
size_t size, gfp_t flags)
{
return ____kasan_kmalloc(cache, object, size, flags);
}
EXPORT_SYMBOL(__kasan_kmalloc);
void * __must_check __kasan_kmalloc_large(const void *ptr, size_t size,
gfp_t flags)
{
unsigned long redzone_start;
unsigned long redzone_end;
if (gfpflags_allow_blocking(flags))
kasan_quarantine_reduce();
if (unlikely(ptr == NULL))
return NULL;
/*
* The object has already been unpoisoned by kasan_unpoison_pages() for
* alloc_pages() or by kasan_krealloc() for krealloc().
*/
/*
* The redzone has byte-level precision for the generic mode.
* Partially poison the last object granule to cover the unaligned
* part of the redzone.
*/
if (IS_ENABLED(CONFIG_KASAN_GENERIC))
kasan_poison_last_granule(ptr, size);
/* Poison the aligned part of the redzone. */
redzone_start = round_up((unsigned long)(ptr + size),
KASAN_GRANULE_SIZE);
redzone_end = (unsigned long)ptr + page_size(virt_to_page(ptr));
kasan_poison((void *)redzone_start, redzone_end - redzone_start,
KASAN_PAGE_REDZONE, false);
return (void *)ptr;
}
void * __must_check __kasan_krealloc(const void *object, size_t size, gfp_t flags)
{
struct slab *slab;
if (unlikely(object == ZERO_SIZE_PTR))
return (void *)object;
/*
* Unpoison the object's data.
* Part of it might already have been unpoisoned, but it's unknown
* how big that part is.
*/
kasan_unpoison(object, size, false);
slab = virt_to_slab(object);
/* Piggy-back on kmalloc() instrumentation to poison the redzone. */
if (unlikely(!slab))
return __kasan_kmalloc_large(object, size, flags);
else
return ____kasan_kmalloc(slab->slab_cache, object, size, flags);
}
bool __kasan_check_byte(const void *address, unsigned long ip)
{
if (!kasan_byte_accessible(address)) {
kasan_report(address, 1, false, ip);
return false;
}
return true;
}
| linux-master | mm/kasan/common.c |
// SPDX-License-Identifier: GPL-2.0
/*
* This file contains KASAN runtime code that manages shadow memory for
* generic and software tag-based KASAN modes.
*
* Copyright (c) 2014 Samsung Electronics Co., Ltd.
* Author: Andrey Ryabinin <[email protected]>
*
* Some code borrowed from https://github.com/xairy/kasan-prototype by
* Andrey Konovalov <[email protected]>
*/
#include <linux/init.h>
#include <linux/kasan.h>
#include <linux/kernel.h>
#include <linux/kfence.h>
#include <linux/kmemleak.h>
#include <linux/memory.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/vmalloc.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include "kasan.h"
bool __kasan_check_read(const volatile void *p, unsigned int size)
{
return kasan_check_range((void *)p, size, false, _RET_IP_);
}
EXPORT_SYMBOL(__kasan_check_read);
bool __kasan_check_write(const volatile void *p, unsigned int size)
{
return kasan_check_range((void *)p, size, true, _RET_IP_);
}
EXPORT_SYMBOL(__kasan_check_write);
#if !defined(CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX) && !defined(CONFIG_GENERIC_ENTRY)
/*
* CONFIG_GENERIC_ENTRY relies on compiler emitted mem*() calls to not be
* instrumented. KASAN enabled toolchains should emit __asan_mem*() functions
* for the sites they want to instrument.
*
* If we have a compiler that can instrument meminstrinsics, never override
* these, so that non-instrumented files can safely consider them as builtins.
*/
#undef memset
void *memset(void *addr, int c, size_t len)
{
if (!kasan_check_range(addr, len, true, _RET_IP_))
return NULL;
return __memset(addr, c, len);
}
#ifdef __HAVE_ARCH_MEMMOVE
#undef memmove
void *memmove(void *dest, const void *src, size_t len)
{
if (!kasan_check_range(src, len, false, _RET_IP_) ||
!kasan_check_range(dest, len, true, _RET_IP_))
return NULL;
return __memmove(dest, src, len);
}
#endif
#undef memcpy
void *memcpy(void *dest, const void *src, size_t len)
{
if (!kasan_check_range(src, len, false, _RET_IP_) ||
!kasan_check_range(dest, len, true, _RET_IP_))
return NULL;
return __memcpy(dest, src, len);
}
#endif
void *__asan_memset(void *addr, int c, ssize_t len)
{
if (!kasan_check_range(addr, len, true, _RET_IP_))
return NULL;
return __memset(addr, c, len);
}
EXPORT_SYMBOL(__asan_memset);
#ifdef __HAVE_ARCH_MEMMOVE
void *__asan_memmove(void *dest, const void *src, ssize_t len)
{
if (!kasan_check_range(src, len, false, _RET_IP_) ||
!kasan_check_range(dest, len, true, _RET_IP_))
return NULL;
return __memmove(dest, src, len);
}
EXPORT_SYMBOL(__asan_memmove);
#endif
void *__asan_memcpy(void *dest, const void *src, ssize_t len)
{
if (!kasan_check_range(src, len, false, _RET_IP_) ||
!kasan_check_range(dest, len, true, _RET_IP_))
return NULL;
return __memcpy(dest, src, len);
}
EXPORT_SYMBOL(__asan_memcpy);
#ifdef CONFIG_KASAN_SW_TAGS
void *__hwasan_memset(void *addr, int c, ssize_t len) __alias(__asan_memset);
EXPORT_SYMBOL(__hwasan_memset);
#ifdef __HAVE_ARCH_MEMMOVE
void *__hwasan_memmove(void *dest, const void *src, ssize_t len) __alias(__asan_memmove);
EXPORT_SYMBOL(__hwasan_memmove);
#endif
void *__hwasan_memcpy(void *dest, const void *src, ssize_t len) __alias(__asan_memcpy);
EXPORT_SYMBOL(__hwasan_memcpy);
#endif
void kasan_poison(const void *addr, size_t size, u8 value, bool init)
{
void *shadow_start, *shadow_end;
if (!kasan_arch_is_ready())
return;
/*
* Perform shadow offset calculation based on untagged address, as
* some of the callers (e.g. kasan_poison_object_data) pass tagged
* addresses to this function.
*/
addr = kasan_reset_tag(addr);
/* Skip KFENCE memory if called explicitly outside of sl*b. */
if (is_kfence_address(addr))
return;
if (WARN_ON((unsigned long)addr & KASAN_GRANULE_MASK))
return;
if (WARN_ON(size & KASAN_GRANULE_MASK))
return;
shadow_start = kasan_mem_to_shadow(addr);
shadow_end = kasan_mem_to_shadow(addr + size);
__memset(shadow_start, value, shadow_end - shadow_start);
}
EXPORT_SYMBOL(kasan_poison);
#ifdef CONFIG_KASAN_GENERIC
void kasan_poison_last_granule(const void *addr, size_t size)
{
if (!kasan_arch_is_ready())
return;
if (size & KASAN_GRANULE_MASK) {
u8 *shadow = (u8 *)kasan_mem_to_shadow(addr + size);
*shadow = size & KASAN_GRANULE_MASK;
}
}
#endif
void kasan_unpoison(const void *addr, size_t size, bool init)
{
u8 tag = get_tag(addr);
/*
* Perform shadow offset calculation based on untagged address, as
* some of the callers (e.g. kasan_unpoison_object_data) pass tagged
* addresses to this function.
*/
addr = kasan_reset_tag(addr);
/*
* Skip KFENCE memory if called explicitly outside of sl*b. Also note
* that calls to ksize(), where size is not a multiple of machine-word
* size, would otherwise poison the invalid portion of the word.
*/
if (is_kfence_address(addr))
return;
if (WARN_ON((unsigned long)addr & KASAN_GRANULE_MASK))
return;
/* Unpoison all granules that cover the object. */
kasan_poison(addr, round_up(size, KASAN_GRANULE_SIZE), tag, false);
/* Partially poison the last granule for the generic mode. */
if (IS_ENABLED(CONFIG_KASAN_GENERIC))
kasan_poison_last_granule(addr, size);
}
#ifdef CONFIG_MEMORY_HOTPLUG
static bool shadow_mapped(unsigned long addr)
{
pgd_t *pgd = pgd_offset_k(addr);
p4d_t *p4d;
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
if (pgd_none(*pgd))
return false;
p4d = p4d_offset(pgd, addr);
if (p4d_none(*p4d))
return false;
pud = pud_offset(p4d, addr);
if (pud_none(*pud))
return false;
/*
* We can't use pud_large() or pud_huge(), the first one is
* arch-specific, the last one depends on HUGETLB_PAGE. So let's abuse
* pud_bad(), if pud is bad then it's bad because it's huge.
*/
if (pud_bad(*pud))
return true;
pmd = pmd_offset(pud, addr);
if (pmd_none(*pmd))
return false;
if (pmd_bad(*pmd))
return true;
pte = pte_offset_kernel(pmd, addr);
return !pte_none(ptep_get(pte));
}
static int __meminit kasan_mem_notifier(struct notifier_block *nb,
unsigned long action, void *data)
{
struct memory_notify *mem_data = data;
unsigned long nr_shadow_pages, start_kaddr, shadow_start;
unsigned long shadow_end, shadow_size;
nr_shadow_pages = mem_data->nr_pages >> KASAN_SHADOW_SCALE_SHIFT;
start_kaddr = (unsigned long)pfn_to_kaddr(mem_data->start_pfn);
shadow_start = (unsigned long)kasan_mem_to_shadow((void *)start_kaddr);
shadow_size = nr_shadow_pages << PAGE_SHIFT;
shadow_end = shadow_start + shadow_size;
if (WARN_ON(mem_data->nr_pages % KASAN_GRANULE_SIZE) ||
WARN_ON(start_kaddr % KASAN_MEMORY_PER_SHADOW_PAGE))
return NOTIFY_BAD;
switch (action) {
case MEM_GOING_ONLINE: {
void *ret;
/*
* If shadow is mapped already than it must have been mapped
* during the boot. This could happen if we onlining previously
* offlined memory.
*/
if (shadow_mapped(shadow_start))
return NOTIFY_OK;
ret = __vmalloc_node_range(shadow_size, PAGE_SIZE, shadow_start,
shadow_end, GFP_KERNEL,
PAGE_KERNEL, VM_NO_GUARD,
pfn_to_nid(mem_data->start_pfn),
__builtin_return_address(0));
if (!ret)
return NOTIFY_BAD;
kmemleak_ignore(ret);
return NOTIFY_OK;
}
case MEM_CANCEL_ONLINE:
case MEM_OFFLINE: {
struct vm_struct *vm;
/*
* shadow_start was either mapped during boot by kasan_init()
* or during memory online by __vmalloc_node_range().
* In the latter case we can use vfree() to free shadow.
* Non-NULL result of the find_vm_area() will tell us if
* that was the second case.
*
* Currently it's not possible to free shadow mapped
* during boot by kasan_init(). It's because the code
* to do that hasn't been written yet. So we'll just
* leak the memory.
*/
vm = find_vm_area((void *)shadow_start);
if (vm)
vfree((void *)shadow_start);
}
}
return NOTIFY_OK;
}
static int __init kasan_memhotplug_init(void)
{
hotplug_memory_notifier(kasan_mem_notifier, DEFAULT_CALLBACK_PRI);
return 0;
}
core_initcall(kasan_memhotplug_init);
#endif
#ifdef CONFIG_KASAN_VMALLOC
void __init __weak kasan_populate_early_vm_area_shadow(void *start,
unsigned long size)
{
}
static int kasan_populate_vmalloc_pte(pte_t *ptep, unsigned long addr,
void *unused)
{
unsigned long page;
pte_t pte;
if (likely(!pte_none(ptep_get(ptep))))
return 0;
page = __get_free_page(GFP_KERNEL);
if (!page)
return -ENOMEM;
memset((void *)page, KASAN_VMALLOC_INVALID, PAGE_SIZE);
pte = pfn_pte(PFN_DOWN(__pa(page)), PAGE_KERNEL);
spin_lock(&init_mm.page_table_lock);
if (likely(pte_none(ptep_get(ptep)))) {
set_pte_at(&init_mm, addr, ptep, pte);
page = 0;
}
spin_unlock(&init_mm.page_table_lock);
if (page)
free_page(page);
return 0;
}
int kasan_populate_vmalloc(unsigned long addr, unsigned long size)
{
unsigned long shadow_start, shadow_end;
int ret;
if (!kasan_arch_is_ready())
return 0;
if (!is_vmalloc_or_module_addr((void *)addr))
return 0;
shadow_start = (unsigned long)kasan_mem_to_shadow((void *)addr);
shadow_end = (unsigned long)kasan_mem_to_shadow((void *)addr + size);
/*
* User Mode Linux maps enough shadow memory for all of virtual memory
* at boot, so doesn't need to allocate more on vmalloc, just clear it.
*
* The remaining CONFIG_UML checks in this file exist for the same
* reason.
*/
if (IS_ENABLED(CONFIG_UML)) {
__memset((void *)shadow_start, KASAN_VMALLOC_INVALID, shadow_end - shadow_start);
return 0;
}
shadow_start = PAGE_ALIGN_DOWN(shadow_start);
shadow_end = PAGE_ALIGN(shadow_end);
ret = apply_to_page_range(&init_mm, shadow_start,
shadow_end - shadow_start,
kasan_populate_vmalloc_pte, NULL);
if (ret)
return ret;
flush_cache_vmap(shadow_start, shadow_end);
/*
* We need to be careful about inter-cpu effects here. Consider:
*
* CPU#0 CPU#1
* WRITE_ONCE(p, vmalloc(100)); while (x = READ_ONCE(p)) ;
* p[99] = 1;
*
* With compiler instrumentation, that ends up looking like this:
*
* CPU#0 CPU#1
* // vmalloc() allocates memory
* // let a = area->addr
* // we reach kasan_populate_vmalloc
* // and call kasan_unpoison:
* STORE shadow(a), unpoison_val
* ...
* STORE shadow(a+99), unpoison_val x = LOAD p
* // rest of vmalloc process <data dependency>
* STORE p, a LOAD shadow(x+99)
*
* If there is no barrier between the end of unpoisoning the shadow
* and the store of the result to p, the stores could be committed
* in a different order by CPU#0, and CPU#1 could erroneously observe
* poison in the shadow.
*
* We need some sort of barrier between the stores.
*
* In the vmalloc() case, this is provided by a smp_wmb() in
* clear_vm_uninitialized_flag(). In the per-cpu allocator and in
* get_vm_area() and friends, the caller gets shadow allocated but
* doesn't have any pages mapped into the virtual address space that
* has been reserved. Mapping those pages in will involve taking and
* releasing a page-table lock, which will provide the barrier.
*/
return 0;
}
static int kasan_depopulate_vmalloc_pte(pte_t *ptep, unsigned long addr,
void *unused)
{
unsigned long page;
page = (unsigned long)__va(pte_pfn(ptep_get(ptep)) << PAGE_SHIFT);
spin_lock(&init_mm.page_table_lock);
if (likely(!pte_none(ptep_get(ptep)))) {
pte_clear(&init_mm, addr, ptep);
free_page(page);
}
spin_unlock(&init_mm.page_table_lock);
return 0;
}
/*
* Release the backing for the vmalloc region [start, end), which
* lies within the free region [free_region_start, free_region_end).
*
* This can be run lazily, long after the region was freed. It runs
* under vmap_area_lock, so it's not safe to interact with the vmalloc/vmap
* infrastructure.
*
* How does this work?
* -------------------
*
* We have a region that is page aligned, labeled as A.
* That might not map onto the shadow in a way that is page-aligned:
*
* start end
* v v
* |????????|????????|AAAAAAAA|AA....AA|AAAAAAAA|????????| < vmalloc
* -------- -------- -------- -------- --------
* | | | | |
* | | | /-------/ |
* \-------\|/------/ |/---------------/
* ||| ||
* |??AAAAAA|AAAAAAAA|AA??????| < shadow
* (1) (2) (3)
*
* First we align the start upwards and the end downwards, so that the
* shadow of the region aligns with shadow page boundaries. In the
* example, this gives us the shadow page (2). This is the shadow entirely
* covered by this allocation.
*
* Then we have the tricky bits. We want to know if we can free the
* partially covered shadow pages - (1) and (3) in the example. For this,
* we are given the start and end of the free region that contains this
* allocation. Extending our previous example, we could have:
*
* free_region_start free_region_end
* | start end |
* v v v v
* |FFFFFFFF|FFFFFFFF|AAAAAAAA|AA....AA|AAAAAAAA|FFFFFFFF| < vmalloc
* -------- -------- -------- -------- --------
* | | | | |
* | | | /-------/ |
* \-------\|/------/ |/---------------/
* ||| ||
* |FFAAAAAA|AAAAAAAA|AAF?????| < shadow
* (1) (2) (3)
*
* Once again, we align the start of the free region up, and the end of
* the free region down so that the shadow is page aligned. So we can free
* page (1) - we know no allocation currently uses anything in that page,
* because all of it is in the vmalloc free region. But we cannot free
* page (3), because we can't be sure that the rest of it is unused.
*
* We only consider pages that contain part of the original region for
* freeing: we don't try to free other pages from the free region or we'd
* end up trying to free huge chunks of virtual address space.
*
* Concurrency
* -----------
*
* How do we know that we're not freeing a page that is simultaneously
* being used for a fresh allocation in kasan_populate_vmalloc(_pte)?
*
* We _can_ have kasan_release_vmalloc and kasan_populate_vmalloc running
* at the same time. While we run under free_vmap_area_lock, the population
* code does not.
*
* free_vmap_area_lock instead operates to ensure that the larger range
* [free_region_start, free_region_end) is safe: because __alloc_vmap_area and
* the per-cpu region-finding algorithm both run under free_vmap_area_lock,
* no space identified as free will become used while we are running. This
* means that so long as we are careful with alignment and only free shadow
* pages entirely covered by the free region, we will not run in to any
* trouble - any simultaneous allocations will be for disjoint regions.
*/
void kasan_release_vmalloc(unsigned long start, unsigned long end,
unsigned long free_region_start,
unsigned long free_region_end)
{
void *shadow_start, *shadow_end;
unsigned long region_start, region_end;
unsigned long size;
if (!kasan_arch_is_ready())
return;
region_start = ALIGN(start, KASAN_MEMORY_PER_SHADOW_PAGE);
region_end = ALIGN_DOWN(end, KASAN_MEMORY_PER_SHADOW_PAGE);
free_region_start = ALIGN(free_region_start, KASAN_MEMORY_PER_SHADOW_PAGE);
if (start != region_start &&
free_region_start < region_start)
region_start -= KASAN_MEMORY_PER_SHADOW_PAGE;
free_region_end = ALIGN_DOWN(free_region_end, KASAN_MEMORY_PER_SHADOW_PAGE);
if (end != region_end &&
free_region_end > region_end)
region_end += KASAN_MEMORY_PER_SHADOW_PAGE;
shadow_start = kasan_mem_to_shadow((void *)region_start);
shadow_end = kasan_mem_to_shadow((void *)region_end);
if (shadow_end > shadow_start) {
size = shadow_end - shadow_start;
if (IS_ENABLED(CONFIG_UML)) {
__memset(shadow_start, KASAN_SHADOW_INIT, shadow_end - shadow_start);
return;
}
apply_to_existing_page_range(&init_mm,
(unsigned long)shadow_start,
size, kasan_depopulate_vmalloc_pte,
NULL);
flush_tlb_kernel_range((unsigned long)shadow_start,
(unsigned long)shadow_end);
}
}
void *__kasan_unpoison_vmalloc(const void *start, unsigned long size,
kasan_vmalloc_flags_t flags)
{
/*
* Software KASAN modes unpoison both VM_ALLOC and non-VM_ALLOC
* mappings, so the KASAN_VMALLOC_VM_ALLOC flag is ignored.
* Software KASAN modes can't optimize zeroing memory by combining it
* with setting memory tags, so the KASAN_VMALLOC_INIT flag is ignored.
*/
if (!kasan_arch_is_ready())
return (void *)start;
if (!is_vmalloc_or_module_addr(start))
return (void *)start;
/*
* Don't tag executable memory with the tag-based mode.
* The kernel doesn't tolerate having the PC register tagged.
*/
if (IS_ENABLED(CONFIG_KASAN_SW_TAGS) &&
!(flags & KASAN_VMALLOC_PROT_NORMAL))
return (void *)start;
start = set_tag(start, kasan_random_tag());
kasan_unpoison(start, size, false);
return (void *)start;
}
/*
* Poison the shadow for a vmalloc region. Called as part of the
* freeing process at the time the region is freed.
*/
void __kasan_poison_vmalloc(const void *start, unsigned long size)
{
if (!kasan_arch_is_ready())
return;
if (!is_vmalloc_or_module_addr(start))
return;
size = round_up(size, KASAN_GRANULE_SIZE);
kasan_poison(start, size, KASAN_VMALLOC_INVALID, false);
}
#else /* CONFIG_KASAN_VMALLOC */
int kasan_alloc_module_shadow(void *addr, size_t size, gfp_t gfp_mask)
{
void *ret;
size_t scaled_size;
size_t shadow_size;
unsigned long shadow_start;
shadow_start = (unsigned long)kasan_mem_to_shadow(addr);
scaled_size = (size + KASAN_GRANULE_SIZE - 1) >>
KASAN_SHADOW_SCALE_SHIFT;
shadow_size = round_up(scaled_size, PAGE_SIZE);
if (WARN_ON(!PAGE_ALIGNED(shadow_start)))
return -EINVAL;
if (IS_ENABLED(CONFIG_UML)) {
__memset((void *)shadow_start, KASAN_SHADOW_INIT, shadow_size);
return 0;
}
ret = __vmalloc_node_range(shadow_size, 1, shadow_start,
shadow_start + shadow_size,
GFP_KERNEL,
PAGE_KERNEL, VM_NO_GUARD, NUMA_NO_NODE,
__builtin_return_address(0));
if (ret) {
struct vm_struct *vm = find_vm_area(addr);
__memset(ret, KASAN_SHADOW_INIT, shadow_size);
vm->flags |= VM_KASAN;
kmemleak_ignore(ret);
if (vm->flags & VM_DEFER_KMEMLEAK)
kmemleak_vmalloc(vm, size, gfp_mask);
return 0;
}
return -ENOMEM;
}
void kasan_free_module_shadow(const struct vm_struct *vm)
{
if (IS_ENABLED(CONFIG_UML))
return;
if (vm->flags & VM_KASAN)
vfree(kasan_mem_to_shadow(vm->addr));
}
#endif
| linux-master | mm/kasan/shadow.c |
// SPDX-License-Identifier: GPL-2.0
/*
* This file contains common tag-based KASAN code.
*
* Copyright (c) 2018 Google, Inc.
* Copyright (c) 2020 Google, Inc.
*/
#include <linux/atomic.h>
#include <linux/init.h>
#include <linux/kasan.h>
#include <linux/kernel.h>
#include <linux/memblock.h>
#include <linux/memory.h>
#include <linux/mm.h>
#include <linux/static_key.h>
#include <linux/string.h>
#include <linux/types.h>
#include "kasan.h"
#include "../slab.h"
#define KASAN_STACK_RING_SIZE_DEFAULT (32 << 10)
enum kasan_arg_stacktrace {
KASAN_ARG_STACKTRACE_DEFAULT,
KASAN_ARG_STACKTRACE_OFF,
KASAN_ARG_STACKTRACE_ON,
};
static enum kasan_arg_stacktrace kasan_arg_stacktrace __initdata;
/* Whether to collect alloc/free stack traces. */
DEFINE_STATIC_KEY_TRUE(kasan_flag_stacktrace);
/* Non-zero, as initial pointer values are 0. */
#define STACK_RING_BUSY_PTR ((void *)1)
struct kasan_stack_ring stack_ring = {
.lock = __RW_LOCK_UNLOCKED(stack_ring.lock)
};
/* kasan.stacktrace=off/on */
static int __init early_kasan_flag_stacktrace(char *arg)
{
if (!arg)
return -EINVAL;
if (!strcmp(arg, "off"))
kasan_arg_stacktrace = KASAN_ARG_STACKTRACE_OFF;
else if (!strcmp(arg, "on"))
kasan_arg_stacktrace = KASAN_ARG_STACKTRACE_ON;
else
return -EINVAL;
return 0;
}
early_param("kasan.stacktrace", early_kasan_flag_stacktrace);
/* kasan.stack_ring_size=<number of entries> */
static int __init early_kasan_flag_stack_ring_size(char *arg)
{
if (!arg)
return -EINVAL;
return kstrtoul(arg, 0, &stack_ring.size);
}
early_param("kasan.stack_ring_size", early_kasan_flag_stack_ring_size);
void __init kasan_init_tags(void)
{
switch (kasan_arg_stacktrace) {
case KASAN_ARG_STACKTRACE_DEFAULT:
/* Default is specified by kasan_flag_stacktrace definition. */
break;
case KASAN_ARG_STACKTRACE_OFF:
static_branch_disable(&kasan_flag_stacktrace);
break;
case KASAN_ARG_STACKTRACE_ON:
static_branch_enable(&kasan_flag_stacktrace);
break;
}
if (kasan_stack_collection_enabled()) {
if (!stack_ring.size)
stack_ring.size = KASAN_STACK_RING_SIZE_DEFAULT;
stack_ring.entries = memblock_alloc(
sizeof(stack_ring.entries[0]) * stack_ring.size,
SMP_CACHE_BYTES);
if (WARN_ON(!stack_ring.entries))
static_branch_disable(&kasan_flag_stacktrace);
}
}
static void save_stack_info(struct kmem_cache *cache, void *object,
gfp_t gfp_flags, bool is_free)
{
unsigned long flags;
depot_stack_handle_t stack;
u64 pos;
struct kasan_stack_ring_entry *entry;
void *old_ptr;
stack = kasan_save_stack(gfp_flags, true);
/*
* Prevent save_stack_info() from modifying stack ring
* when kasan_complete_mode_report_info() is walking it.
*/
read_lock_irqsave(&stack_ring.lock, flags);
next:
pos = atomic64_fetch_add(1, &stack_ring.pos);
entry = &stack_ring.entries[pos % stack_ring.size];
/* Detect stack ring entry slots that are being written to. */
old_ptr = READ_ONCE(entry->ptr);
if (old_ptr == STACK_RING_BUSY_PTR)
goto next; /* Busy slot. */
if (!try_cmpxchg(&entry->ptr, &old_ptr, STACK_RING_BUSY_PTR))
goto next; /* Busy slot. */
WRITE_ONCE(entry->size, cache->object_size);
WRITE_ONCE(entry->pid, current->pid);
WRITE_ONCE(entry->stack, stack);
WRITE_ONCE(entry->is_free, is_free);
/*
* Paired with smp_load_acquire() in kasan_complete_mode_report_info().
*/
smp_store_release(&entry->ptr, (s64)object);
read_unlock_irqrestore(&stack_ring.lock, flags);
}
void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags)
{
save_stack_info(cache, object, flags, false);
}
void kasan_save_free_info(struct kmem_cache *cache, void *object)
{
save_stack_info(cache, object, 0, true);
}
| linux-master | mm/kasan/tags.c |
// SPDX-License-Identifier: GPL-2.0
/*
* This file contains common KASAN error reporting code.
*
* Copyright (c) 2014 Samsung Electronics Co., Ltd.
* Author: Andrey Ryabinin <[email protected]>
*
* Some code borrowed from https://github.com/xairy/kasan-prototype by
* Andrey Konovalov <[email protected]>
*/
#include <kunit/test.h>
#include <linux/bitops.h>
#include <linux/ftrace.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/lockdep.h>
#include <linux/mm.h>
#include <linux/printk.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/stackdepot.h>
#include <linux/stacktrace.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/kasan.h>
#include <linux/module.h>
#include <linux/sched/task_stack.h>
#include <linux/uaccess.h>
#include <trace/events/error_report.h>
#include <asm/sections.h>
#include "kasan.h"
#include "../slab.h"
static unsigned long kasan_flags;
#define KASAN_BIT_REPORTED 0
#define KASAN_BIT_MULTI_SHOT 1
enum kasan_arg_fault {
KASAN_ARG_FAULT_DEFAULT,
KASAN_ARG_FAULT_REPORT,
KASAN_ARG_FAULT_PANIC,
KASAN_ARG_FAULT_PANIC_ON_WRITE,
};
static enum kasan_arg_fault kasan_arg_fault __ro_after_init = KASAN_ARG_FAULT_DEFAULT;
/* kasan.fault=report/panic */
static int __init early_kasan_fault(char *arg)
{
if (!arg)
return -EINVAL;
if (!strcmp(arg, "report"))
kasan_arg_fault = KASAN_ARG_FAULT_REPORT;
else if (!strcmp(arg, "panic"))
kasan_arg_fault = KASAN_ARG_FAULT_PANIC;
else if (!strcmp(arg, "panic_on_write"))
kasan_arg_fault = KASAN_ARG_FAULT_PANIC_ON_WRITE;
else
return -EINVAL;
return 0;
}
early_param("kasan.fault", early_kasan_fault);
static int __init kasan_set_multi_shot(char *str)
{
set_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags);
return 1;
}
__setup("kasan_multi_shot", kasan_set_multi_shot);
/*
* This function is used to check whether KASAN reports are suppressed for
* software KASAN modes via kasan_disable/enable_current() critical sections.
*
* This is done to avoid:
* 1. False-positive reports when accessing slab metadata,
* 2. Deadlocking when poisoned memory is accessed by the reporting code.
*
* Hardware Tag-Based KASAN instead relies on:
* For #1: Resetting tags via kasan_reset_tag().
* For #2: Suppression of tag checks via CPU, see report_suppress_start/end().
*/
static bool report_suppressed_sw(void)
{
#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
if (current->kasan_depth)
return true;
#endif
return false;
}
static void report_suppress_start(void)
{
#ifdef CONFIG_KASAN_HW_TAGS
/*
* Disable preemption for the duration of printing a KASAN report, as
* hw_suppress_tag_checks_start() disables checks on the current CPU.
*/
preempt_disable();
hw_suppress_tag_checks_start();
#else
kasan_disable_current();
#endif
}
static void report_suppress_stop(void)
{
#ifdef CONFIG_KASAN_HW_TAGS
hw_suppress_tag_checks_stop();
preempt_enable();
#else
kasan_enable_current();
#endif
}
/*
* Used to avoid reporting more than one KASAN bug unless kasan_multi_shot
* is enabled. Note that KASAN tests effectively enable kasan_multi_shot
* for their duration.
*/
static bool report_enabled(void)
{
if (test_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags))
return true;
return !test_and_set_bit(KASAN_BIT_REPORTED, &kasan_flags);
}
#if IS_ENABLED(CONFIG_KASAN_KUNIT_TEST) || IS_ENABLED(CONFIG_KASAN_MODULE_TEST)
bool kasan_save_enable_multi_shot(void)
{
return test_and_set_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags);
}
EXPORT_SYMBOL_GPL(kasan_save_enable_multi_shot);
void kasan_restore_multi_shot(bool enabled)
{
if (!enabled)
clear_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags);
}
EXPORT_SYMBOL_GPL(kasan_restore_multi_shot);
#endif
#if IS_ENABLED(CONFIG_KASAN_KUNIT_TEST)
/*
* Whether the KASAN KUnit test suite is currently being executed.
* Updated in kasan_test.c.
*/
static bool kasan_kunit_executing;
void kasan_kunit_test_suite_start(void)
{
WRITE_ONCE(kasan_kunit_executing, true);
}
EXPORT_SYMBOL_GPL(kasan_kunit_test_suite_start);
void kasan_kunit_test_suite_end(void)
{
WRITE_ONCE(kasan_kunit_executing, false);
}
EXPORT_SYMBOL_GPL(kasan_kunit_test_suite_end);
static bool kasan_kunit_test_suite_executing(void)
{
return READ_ONCE(kasan_kunit_executing);
}
#else /* CONFIG_KASAN_KUNIT_TEST */
static inline bool kasan_kunit_test_suite_executing(void) { return false; }
#endif /* CONFIG_KASAN_KUNIT_TEST */
#if IS_ENABLED(CONFIG_KUNIT)
static void fail_non_kasan_kunit_test(void)
{
struct kunit *test;
if (kasan_kunit_test_suite_executing())
return;
test = current->kunit_test;
if (test)
kunit_set_failure(test);
}
#else /* CONFIG_KUNIT */
static inline void fail_non_kasan_kunit_test(void) { }
#endif /* CONFIG_KUNIT */
static DEFINE_SPINLOCK(report_lock);
static void start_report(unsigned long *flags, bool sync)
{
fail_non_kasan_kunit_test();
/* Respect the /proc/sys/kernel/traceoff_on_warning interface. */
disable_trace_on_warning();
/* Do not allow LOCKDEP mangling KASAN reports. */
lockdep_off();
/* Make sure we don't end up in loop. */
report_suppress_start();
spin_lock_irqsave(&report_lock, *flags);
pr_err("==================================================================\n");
}
static void end_report(unsigned long *flags, const void *addr, bool is_write)
{
if (addr)
trace_error_report_end(ERROR_DETECTOR_KASAN,
(unsigned long)addr);
pr_err("==================================================================\n");
spin_unlock_irqrestore(&report_lock, *flags);
if (!test_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags))
check_panic_on_warn("KASAN");
switch (kasan_arg_fault) {
case KASAN_ARG_FAULT_DEFAULT:
case KASAN_ARG_FAULT_REPORT:
break;
case KASAN_ARG_FAULT_PANIC:
panic("kasan.fault=panic set ...\n");
break;
case KASAN_ARG_FAULT_PANIC_ON_WRITE:
if (is_write)
panic("kasan.fault=panic_on_write set ...\n");
break;
}
add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
lockdep_on();
report_suppress_stop();
}
static void print_error_description(struct kasan_report_info *info)
{
pr_err("BUG: KASAN: %s in %pS\n", info->bug_type, (void *)info->ip);
if (info->type != KASAN_REPORT_ACCESS) {
pr_err("Free of addr %px by task %s/%d\n",
info->access_addr, current->comm, task_pid_nr(current));
return;
}
if (info->access_size)
pr_err("%s of size %zu at addr %px by task %s/%d\n",
info->is_write ? "Write" : "Read", info->access_size,
info->access_addr, current->comm, task_pid_nr(current));
else
pr_err("%s at addr %px by task %s/%d\n",
info->is_write ? "Write" : "Read",
info->access_addr, current->comm, task_pid_nr(current));
}
static void print_track(struct kasan_track *track, const char *prefix)
{
pr_err("%s by task %u:\n", prefix, track->pid);
if (track->stack)
stack_depot_print(track->stack);
else
pr_err("(stack is not available)\n");
}
static inline struct page *addr_to_page(const void *addr)
{
if (virt_addr_valid(addr))
return virt_to_head_page(addr);
return NULL;
}
static void describe_object_addr(const void *addr, struct kasan_report_info *info)
{
unsigned long access_addr = (unsigned long)addr;
unsigned long object_addr = (unsigned long)info->object;
const char *rel_type, *region_state = "";
int rel_bytes;
pr_err("The buggy address belongs to the object at %px\n"
" which belongs to the cache %s of size %d\n",
info->object, info->cache->name, info->cache->object_size);
if (access_addr < object_addr) {
rel_type = "to the left";
rel_bytes = object_addr - access_addr;
} else if (access_addr >= object_addr + info->alloc_size) {
rel_type = "to the right";
rel_bytes = access_addr - (object_addr + info->alloc_size);
} else {
rel_type = "inside";
rel_bytes = access_addr - object_addr;
}
/*
* Tag-Based modes use the stack ring to infer the bug type, but the
* memory region state description is generated based on the metadata.
* Thus, defining the region state as below can contradict the metadata.
* Fixing this requires further improvements, so only infer the state
* for the Generic mode.
*/
if (IS_ENABLED(CONFIG_KASAN_GENERIC)) {
if (strcmp(info->bug_type, "slab-out-of-bounds") == 0)
region_state = "allocated ";
else if (strcmp(info->bug_type, "slab-use-after-free") == 0)
region_state = "freed ";
}
pr_err("The buggy address is located %d bytes %s of\n"
" %s%zu-byte region [%px, %px)\n",
rel_bytes, rel_type, region_state, info->alloc_size,
(void *)object_addr, (void *)(object_addr + info->alloc_size));
}
static void describe_object_stacks(struct kasan_report_info *info)
{
if (info->alloc_track.stack) {
print_track(&info->alloc_track, "Allocated");
pr_err("\n");
}
if (info->free_track.stack) {
print_track(&info->free_track, "Freed");
pr_err("\n");
}
kasan_print_aux_stacks(info->cache, info->object);
}
static void describe_object(const void *addr, struct kasan_report_info *info)
{
if (kasan_stack_collection_enabled())
describe_object_stacks(info);
describe_object_addr(addr, info);
}
static inline bool kernel_or_module_addr(const void *addr)
{
if (is_kernel((unsigned long)addr))
return true;
if (is_module_address((unsigned long)addr))
return true;
return false;
}
static inline bool init_task_stack_addr(const void *addr)
{
return addr >= (void *)&init_thread_union.stack &&
(addr <= (void *)&init_thread_union.stack +
sizeof(init_thread_union.stack));
}
static void print_address_description(void *addr, u8 tag,
struct kasan_report_info *info)
{
struct page *page = addr_to_page(addr);
dump_stack_lvl(KERN_ERR);
pr_err("\n");
if (info->cache && info->object) {
describe_object(addr, info);
pr_err("\n");
}
if (kernel_or_module_addr(addr) && !init_task_stack_addr(addr)) {
pr_err("The buggy address belongs to the variable:\n");
pr_err(" %pS\n", addr);
pr_err("\n");
}
if (object_is_on_stack(addr)) {
/*
* Currently, KASAN supports printing frame information only
* for accesses to the task's own stack.
*/
kasan_print_address_stack_frame(addr);
pr_err("\n");
}
if (is_vmalloc_addr(addr)) {
struct vm_struct *va = find_vm_area(addr);
if (va) {
pr_err("The buggy address belongs to the virtual mapping at\n"
" [%px, %px) created by:\n"
" %pS\n",
va->addr, va->addr + va->size, va->caller);
pr_err("\n");
page = vmalloc_to_page(addr);
}
}
if (page) {
pr_err("The buggy address belongs to the physical page:\n");
dump_page(page, "kasan: bad access detected");
pr_err("\n");
}
}
static bool meta_row_is_guilty(const void *row, const void *addr)
{
return (row <= addr) && (addr < row + META_MEM_BYTES_PER_ROW);
}
static int meta_pointer_offset(const void *row, const void *addr)
{
/*
* Memory state around the buggy address:
* ff00ff00ff00ff00: 00 00 00 05 fe fe fe fe fe fe fe fe fe fe fe fe
* ...
*
* The length of ">ff00ff00ff00ff00: " is
* 3 + (BITS_PER_LONG / 8) * 2 chars.
* The length of each granule metadata is 2 bytes
* plus 1 byte for space.
*/
return 3 + (BITS_PER_LONG / 8) * 2 +
(addr - row) / KASAN_GRANULE_SIZE * 3 + 1;
}
static void print_memory_metadata(const void *addr)
{
int i;
void *row;
row = (void *)round_down((unsigned long)addr, META_MEM_BYTES_PER_ROW)
- META_ROWS_AROUND_ADDR * META_MEM_BYTES_PER_ROW;
pr_err("Memory state around the buggy address:\n");
for (i = -META_ROWS_AROUND_ADDR; i <= META_ROWS_AROUND_ADDR; i++) {
char buffer[4 + (BITS_PER_LONG / 8) * 2];
char metadata[META_BYTES_PER_ROW];
snprintf(buffer, sizeof(buffer),
(i == 0) ? ">%px: " : " %px: ", row);
/*
* We should not pass a shadow pointer to generic
* function, because generic functions may try to
* access kasan mapping for the passed address.
*/
kasan_metadata_fetch_row(&metadata[0], row);
print_hex_dump(KERN_ERR, buffer,
DUMP_PREFIX_NONE, META_BYTES_PER_ROW, 1,
metadata, META_BYTES_PER_ROW, 0);
if (meta_row_is_guilty(row, addr))
pr_err("%*c\n", meta_pointer_offset(row, addr), '^');
row += META_MEM_BYTES_PER_ROW;
}
}
static void print_report(struct kasan_report_info *info)
{
void *addr = kasan_reset_tag((void *)info->access_addr);
u8 tag = get_tag((void *)info->access_addr);
print_error_description(info);
if (addr_has_metadata(addr))
kasan_print_tags(tag, info->first_bad_addr);
pr_err("\n");
if (addr_has_metadata(addr)) {
print_address_description(addr, tag, info);
print_memory_metadata(info->first_bad_addr);
} else {
dump_stack_lvl(KERN_ERR);
}
}
static void complete_report_info(struct kasan_report_info *info)
{
void *addr = kasan_reset_tag((void *)info->access_addr);
struct slab *slab;
if (info->type == KASAN_REPORT_ACCESS)
info->first_bad_addr = kasan_find_first_bad_addr(
(void *)info->access_addr, info->access_size);
else
info->first_bad_addr = addr;
slab = kasan_addr_to_slab(addr);
if (slab) {
info->cache = slab->slab_cache;
info->object = nearest_obj(info->cache, slab, addr);
/* Try to determine allocation size based on the metadata. */
info->alloc_size = kasan_get_alloc_size(info->object, info->cache);
/* Fallback to the object size if failed. */
if (!info->alloc_size)
info->alloc_size = info->cache->object_size;
} else
info->cache = info->object = NULL;
switch (info->type) {
case KASAN_REPORT_INVALID_FREE:
info->bug_type = "invalid-free";
break;
case KASAN_REPORT_DOUBLE_FREE:
info->bug_type = "double-free";
break;
default:
/* bug_type filled in by kasan_complete_mode_report_info. */
break;
}
/* Fill in mode-specific report info fields. */
kasan_complete_mode_report_info(info);
}
void kasan_report_invalid_free(void *ptr, unsigned long ip, enum kasan_report_type type)
{
unsigned long flags;
struct kasan_report_info info;
/*
* Do not check report_suppressed_sw(), as an invalid-free cannot be
* caused by accessing poisoned memory and thus should not be suppressed
* by kasan_disable/enable_current() critical sections.
*
* Note that for Hardware Tag-Based KASAN, kasan_report_invalid_free()
* is triggered by explicit tag checks and not by the ones performed by
* the CPU. Thus, reporting invalid-free is not suppressed as well.
*/
if (unlikely(!report_enabled()))
return;
start_report(&flags, true);
memset(&info, 0, sizeof(info));
info.type = type;
info.access_addr = ptr;
info.access_size = 0;
info.is_write = false;
info.ip = ip;
complete_report_info(&info);
print_report(&info);
/*
* Invalid free is considered a "write" since the allocator's metadata
* updates involves writes.
*/
end_report(&flags, ptr, true);
}
/*
* kasan_report() is the only reporting function that uses
* user_access_save/restore(): kasan_report_invalid_free() cannot be called
* from a UACCESS region, and kasan_report_async() is not used on x86.
*/
bool kasan_report(const void *addr, size_t size, bool is_write,
unsigned long ip)
{
bool ret = true;
unsigned long ua_flags = user_access_save();
unsigned long irq_flags;
struct kasan_report_info info;
if (unlikely(report_suppressed_sw()) || unlikely(!report_enabled())) {
ret = false;
goto out;
}
start_report(&irq_flags, true);
memset(&info, 0, sizeof(info));
info.type = KASAN_REPORT_ACCESS;
info.access_addr = addr;
info.access_size = size;
info.is_write = is_write;
info.ip = ip;
complete_report_info(&info);
print_report(&info);
end_report(&irq_flags, (void *)addr, is_write);
out:
user_access_restore(ua_flags);
return ret;
}
#ifdef CONFIG_KASAN_HW_TAGS
void kasan_report_async(void)
{
unsigned long flags;
/*
* Do not check report_suppressed_sw(), as
* kasan_disable/enable_current() critical sections do not affect
* Hardware Tag-Based KASAN.
*/
if (unlikely(!report_enabled()))
return;
start_report(&flags, false);
pr_err("BUG: KASAN: invalid-access\n");
pr_err("Asynchronous fault: no details available\n");
pr_err("\n");
dump_stack_lvl(KERN_ERR);
/*
* Conservatively set is_write=true, because no details are available.
* In this mode, kasan.fault=panic_on_write is like kasan.fault=panic.
*/
end_report(&flags, NULL, true);
}
#endif /* CONFIG_KASAN_HW_TAGS */
#ifdef CONFIG_KASAN_INLINE
/*
* With CONFIG_KASAN_INLINE, accesses to bogus pointers (outside the high
* canonical half of the address space) cause out-of-bounds shadow memory reads
* before the actual access. For addresses in the low canonical half of the
* address space, as well as most non-canonical addresses, that out-of-bounds
* shadow memory access lands in the non-canonical part of the address space.
* Help the user figure out what the original bogus pointer was.
*/
void kasan_non_canonical_hook(unsigned long addr)
{
unsigned long orig_addr;
const char *bug_type;
if (addr < KASAN_SHADOW_OFFSET)
return;
orig_addr = (addr - KASAN_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT;
/*
* For faults near the shadow address for NULL, we can be fairly certain
* that this is a KASAN shadow memory access.
* For faults that correspond to shadow for low canonical addresses, we
* can still be pretty sure - that shadow region is a fairly narrow
* chunk of the non-canonical address space.
* But faults that look like shadow for non-canonical addresses are a
* really large chunk of the address space. In that case, we still
* print the decoded address, but make it clear that this is not
* necessarily what's actually going on.
*/
if (orig_addr < PAGE_SIZE)
bug_type = "null-ptr-deref";
else if (orig_addr < TASK_SIZE)
bug_type = "probably user-memory-access";
else
bug_type = "maybe wild-memory-access";
pr_alert("KASAN: %s in range [0x%016lx-0x%016lx]\n", bug_type,
orig_addr, orig_addr + KASAN_GRANULE_SIZE - 1);
}
#endif
| linux-master | mm/kasan/report.c |
// SPDX-License-Identifier: GPL-2.0
/*
* This file contains KASAN shadow initialization code.
*
* Copyright (c) 2015 Samsung Electronics Co., Ltd.
* Author: Andrey Ryabinin <[email protected]>
*/
#include <linux/memblock.h>
#include <linux/init.h>
#include <linux/kasan.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/pfn.h>
#include <linux/slab.h>
#include <asm/page.h>
#include <asm/pgalloc.h>
#include "kasan.h"
/*
* This page serves two purposes:
* - It used as early shadow memory. The entire shadow region populated
* with this page, before we will be able to setup normal shadow memory.
* - Latter it reused it as zero shadow to cover large ranges of memory
* that allowed to access, but not handled by kasan (vmalloc/vmemmap ...).
*/
unsigned char kasan_early_shadow_page[PAGE_SIZE] __page_aligned_bss;
#if CONFIG_PGTABLE_LEVELS > 4
p4d_t kasan_early_shadow_p4d[MAX_PTRS_PER_P4D] __page_aligned_bss;
static inline bool kasan_p4d_table(pgd_t pgd)
{
return pgd_page(pgd) == virt_to_page(lm_alias(kasan_early_shadow_p4d));
}
#else
static inline bool kasan_p4d_table(pgd_t pgd)
{
return false;
}
#endif
#if CONFIG_PGTABLE_LEVELS > 3
pud_t kasan_early_shadow_pud[MAX_PTRS_PER_PUD] __page_aligned_bss;
static inline bool kasan_pud_table(p4d_t p4d)
{
return p4d_page(p4d) == virt_to_page(lm_alias(kasan_early_shadow_pud));
}
#else
static inline bool kasan_pud_table(p4d_t p4d)
{
return false;
}
#endif
#if CONFIG_PGTABLE_LEVELS > 2
pmd_t kasan_early_shadow_pmd[MAX_PTRS_PER_PMD] __page_aligned_bss;
static inline bool kasan_pmd_table(pud_t pud)
{
return pud_page(pud) == virt_to_page(lm_alias(kasan_early_shadow_pmd));
}
#else
static inline bool kasan_pmd_table(pud_t pud)
{
return false;
}
#endif
pte_t kasan_early_shadow_pte[MAX_PTRS_PER_PTE + PTE_HWTABLE_PTRS]
__page_aligned_bss;
static inline bool kasan_pte_table(pmd_t pmd)
{
return pmd_page(pmd) == virt_to_page(lm_alias(kasan_early_shadow_pte));
}
static inline bool kasan_early_shadow_page_entry(pte_t pte)
{
return pte_page(pte) == virt_to_page(lm_alias(kasan_early_shadow_page));
}
static __init void *early_alloc(size_t size, int node)
{
void *ptr = memblock_alloc_try_nid(size, size, __pa(MAX_DMA_ADDRESS),
MEMBLOCK_ALLOC_ACCESSIBLE, node);
if (!ptr)
panic("%s: Failed to allocate %zu bytes align=%zx nid=%d from=%llx\n",
__func__, size, size, node, (u64)__pa(MAX_DMA_ADDRESS));
return ptr;
}
static void __ref zero_pte_populate(pmd_t *pmd, unsigned long addr,
unsigned long end)
{
pte_t *pte = pte_offset_kernel(pmd, addr);
pte_t zero_pte;
zero_pte = pfn_pte(PFN_DOWN(__pa_symbol(kasan_early_shadow_page)),
PAGE_KERNEL);
zero_pte = pte_wrprotect(zero_pte);
while (addr + PAGE_SIZE <= end) {
set_pte_at(&init_mm, addr, pte, zero_pte);
addr += PAGE_SIZE;
pte = pte_offset_kernel(pmd, addr);
}
}
static int __ref zero_pmd_populate(pud_t *pud, unsigned long addr,
unsigned long end)
{
pmd_t *pmd = pmd_offset(pud, addr);
unsigned long next;
do {
next = pmd_addr_end(addr, end);
if (IS_ALIGNED(addr, PMD_SIZE) && end - addr >= PMD_SIZE) {
pmd_populate_kernel(&init_mm, pmd,
lm_alias(kasan_early_shadow_pte));
continue;
}
if (pmd_none(*pmd)) {
pte_t *p;
if (slab_is_available())
p = pte_alloc_one_kernel(&init_mm);
else
p = early_alloc(PAGE_SIZE, NUMA_NO_NODE);
if (!p)
return -ENOMEM;
pmd_populate_kernel(&init_mm, pmd, p);
}
zero_pte_populate(pmd, addr, next);
} while (pmd++, addr = next, addr != end);
return 0;
}
void __weak __meminit pmd_init(void *addr)
{
}
static int __ref zero_pud_populate(p4d_t *p4d, unsigned long addr,
unsigned long end)
{
pud_t *pud = pud_offset(p4d, addr);
unsigned long next;
do {
next = pud_addr_end(addr, end);
if (IS_ALIGNED(addr, PUD_SIZE) && end - addr >= PUD_SIZE) {
pmd_t *pmd;
pud_populate(&init_mm, pud,
lm_alias(kasan_early_shadow_pmd));
pmd = pmd_offset(pud, addr);
pmd_populate_kernel(&init_mm, pmd,
lm_alias(kasan_early_shadow_pte));
continue;
}
if (pud_none(*pud)) {
pmd_t *p;
if (slab_is_available()) {
p = pmd_alloc(&init_mm, pud, addr);
if (!p)
return -ENOMEM;
} else {
p = early_alloc(PAGE_SIZE, NUMA_NO_NODE);
pmd_init(p);
pud_populate(&init_mm, pud, p);
}
}
zero_pmd_populate(pud, addr, next);
} while (pud++, addr = next, addr != end);
return 0;
}
void __weak __meminit pud_init(void *addr)
{
}
static int __ref zero_p4d_populate(pgd_t *pgd, unsigned long addr,
unsigned long end)
{
p4d_t *p4d = p4d_offset(pgd, addr);
unsigned long next;
do {
next = p4d_addr_end(addr, end);
if (IS_ALIGNED(addr, P4D_SIZE) && end - addr >= P4D_SIZE) {
pud_t *pud;
pmd_t *pmd;
p4d_populate(&init_mm, p4d,
lm_alias(kasan_early_shadow_pud));
pud = pud_offset(p4d, addr);
pud_populate(&init_mm, pud,
lm_alias(kasan_early_shadow_pmd));
pmd = pmd_offset(pud, addr);
pmd_populate_kernel(&init_mm, pmd,
lm_alias(kasan_early_shadow_pte));
continue;
}
if (p4d_none(*p4d)) {
pud_t *p;
if (slab_is_available()) {
p = pud_alloc(&init_mm, p4d, addr);
if (!p)
return -ENOMEM;
} else {
p = early_alloc(PAGE_SIZE, NUMA_NO_NODE);
pud_init(p);
p4d_populate(&init_mm, p4d, p);
}
}
zero_pud_populate(p4d, addr, next);
} while (p4d++, addr = next, addr != end);
return 0;
}
/**
* kasan_populate_early_shadow - populate shadow memory region with
* kasan_early_shadow_page
* @shadow_start: start of the memory range to populate
* @shadow_end: end of the memory range to populate
*/
int __ref kasan_populate_early_shadow(const void *shadow_start,
const void *shadow_end)
{
unsigned long addr = (unsigned long)shadow_start;
unsigned long end = (unsigned long)shadow_end;
pgd_t *pgd = pgd_offset_k(addr);
unsigned long next;
do {
next = pgd_addr_end(addr, end);
if (IS_ALIGNED(addr, PGDIR_SIZE) && end - addr >= PGDIR_SIZE) {
p4d_t *p4d;
pud_t *pud;
pmd_t *pmd;
/*
* kasan_early_shadow_pud should be populated with pmds
* at this moment.
* [pud,pmd]_populate*() below needed only for
* 3,2 - level page tables where we don't have
* puds,pmds, so pgd_populate(), pud_populate()
* is noops.
*/
pgd_populate(&init_mm, pgd,
lm_alias(kasan_early_shadow_p4d));
p4d = p4d_offset(pgd, addr);
p4d_populate(&init_mm, p4d,
lm_alias(kasan_early_shadow_pud));
pud = pud_offset(p4d, addr);
pud_populate(&init_mm, pud,
lm_alias(kasan_early_shadow_pmd));
pmd = pmd_offset(pud, addr);
pmd_populate_kernel(&init_mm, pmd,
lm_alias(kasan_early_shadow_pte));
continue;
}
if (pgd_none(*pgd)) {
p4d_t *p;
if (slab_is_available()) {
p = p4d_alloc(&init_mm, pgd, addr);
if (!p)
return -ENOMEM;
} else {
pgd_populate(&init_mm, pgd,
early_alloc(PAGE_SIZE, NUMA_NO_NODE));
}
}
zero_p4d_populate(pgd, addr, next);
} while (pgd++, addr = next, addr != end);
return 0;
}
static void kasan_free_pte(pte_t *pte_start, pmd_t *pmd)
{
pte_t *pte;
int i;
for (i = 0; i < PTRS_PER_PTE; i++) {
pte = pte_start + i;
if (!pte_none(ptep_get(pte)))
return;
}
pte_free_kernel(&init_mm, (pte_t *)page_to_virt(pmd_page(*pmd)));
pmd_clear(pmd);
}
static void kasan_free_pmd(pmd_t *pmd_start, pud_t *pud)
{
pmd_t *pmd;
int i;
for (i = 0; i < PTRS_PER_PMD; i++) {
pmd = pmd_start + i;
if (!pmd_none(*pmd))
return;
}
pmd_free(&init_mm, (pmd_t *)page_to_virt(pud_page(*pud)));
pud_clear(pud);
}
static void kasan_free_pud(pud_t *pud_start, p4d_t *p4d)
{
pud_t *pud;
int i;
for (i = 0; i < PTRS_PER_PUD; i++) {
pud = pud_start + i;
if (!pud_none(*pud))
return;
}
pud_free(&init_mm, (pud_t *)page_to_virt(p4d_page(*p4d)));
p4d_clear(p4d);
}
static void kasan_free_p4d(p4d_t *p4d_start, pgd_t *pgd)
{
p4d_t *p4d;
int i;
for (i = 0; i < PTRS_PER_P4D; i++) {
p4d = p4d_start + i;
if (!p4d_none(*p4d))
return;
}
p4d_free(&init_mm, (p4d_t *)page_to_virt(pgd_page(*pgd)));
pgd_clear(pgd);
}
static void kasan_remove_pte_table(pte_t *pte, unsigned long addr,
unsigned long end)
{
unsigned long next;
pte_t ptent;
for (; addr < end; addr = next, pte++) {
next = (addr + PAGE_SIZE) & PAGE_MASK;
if (next > end)
next = end;
ptent = ptep_get(pte);
if (!pte_present(ptent))
continue;
if (WARN_ON(!kasan_early_shadow_page_entry(ptent)))
continue;
pte_clear(&init_mm, addr, pte);
}
}
static void kasan_remove_pmd_table(pmd_t *pmd, unsigned long addr,
unsigned long end)
{
unsigned long next;
for (; addr < end; addr = next, pmd++) {
pte_t *pte;
next = pmd_addr_end(addr, end);
if (!pmd_present(*pmd))
continue;
if (kasan_pte_table(*pmd)) {
if (IS_ALIGNED(addr, PMD_SIZE) &&
IS_ALIGNED(next, PMD_SIZE)) {
pmd_clear(pmd);
continue;
}
}
pte = pte_offset_kernel(pmd, addr);
kasan_remove_pte_table(pte, addr, next);
kasan_free_pte(pte_offset_kernel(pmd, 0), pmd);
}
}
static void kasan_remove_pud_table(pud_t *pud, unsigned long addr,
unsigned long end)
{
unsigned long next;
for (; addr < end; addr = next, pud++) {
pmd_t *pmd, *pmd_base;
next = pud_addr_end(addr, end);
if (!pud_present(*pud))
continue;
if (kasan_pmd_table(*pud)) {
if (IS_ALIGNED(addr, PUD_SIZE) &&
IS_ALIGNED(next, PUD_SIZE)) {
pud_clear(pud);
continue;
}
}
pmd = pmd_offset(pud, addr);
pmd_base = pmd_offset(pud, 0);
kasan_remove_pmd_table(pmd, addr, next);
kasan_free_pmd(pmd_base, pud);
}
}
static void kasan_remove_p4d_table(p4d_t *p4d, unsigned long addr,
unsigned long end)
{
unsigned long next;
for (; addr < end; addr = next, p4d++) {
pud_t *pud;
next = p4d_addr_end(addr, end);
if (!p4d_present(*p4d))
continue;
if (kasan_pud_table(*p4d)) {
if (IS_ALIGNED(addr, P4D_SIZE) &&
IS_ALIGNED(next, P4D_SIZE)) {
p4d_clear(p4d);
continue;
}
}
pud = pud_offset(p4d, addr);
kasan_remove_pud_table(pud, addr, next);
kasan_free_pud(pud_offset(p4d, 0), p4d);
}
}
void kasan_remove_zero_shadow(void *start, unsigned long size)
{
unsigned long addr, end, next;
pgd_t *pgd;
addr = (unsigned long)kasan_mem_to_shadow(start);
end = addr + (size >> KASAN_SHADOW_SCALE_SHIFT);
if (WARN_ON((unsigned long)start % KASAN_MEMORY_PER_SHADOW_PAGE) ||
WARN_ON(size % KASAN_MEMORY_PER_SHADOW_PAGE))
return;
for (; addr < end; addr = next) {
p4d_t *p4d;
next = pgd_addr_end(addr, end);
pgd = pgd_offset_k(addr);
if (!pgd_present(*pgd))
continue;
if (kasan_p4d_table(*pgd)) {
if (IS_ALIGNED(addr, PGDIR_SIZE) &&
IS_ALIGNED(next, PGDIR_SIZE)) {
pgd_clear(pgd);
continue;
}
}
p4d = p4d_offset(pgd, addr);
kasan_remove_p4d_table(p4d, addr, next);
kasan_free_p4d(p4d_offset(pgd, 0), pgd);
}
}
int kasan_add_zero_shadow(void *start, unsigned long size)
{
int ret;
void *shadow_start, *shadow_end;
shadow_start = kasan_mem_to_shadow(start);
shadow_end = shadow_start + (size >> KASAN_SHADOW_SCALE_SHIFT);
if (WARN_ON((unsigned long)start % KASAN_MEMORY_PER_SHADOW_PAGE) ||
WARN_ON(size % KASAN_MEMORY_PER_SHADOW_PAGE))
return -EINVAL;
ret = kasan_populate_early_shadow(shadow_start, shadow_end);
if (ret)
kasan_remove_zero_shadow(start, size);
return ret;
}
| linux-master | mm/kasan/init.c |
// SPDX-License-Identifier: GPL-2.0
/*
* KASAN quarantine.
*
* Author: Alexander Potapenko <[email protected]>
* Copyright (C) 2016 Google, Inc.
*
* Based on code by Dmitry Chernenkov.
*/
#include <linux/gfp.h>
#include <linux/hash.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/percpu.h>
#include <linux/printk.h>
#include <linux/shrinker.h>
#include <linux/slab.h>
#include <linux/srcu.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/cpuhotplug.h>
#include "../slab.h"
#include "kasan.h"
/* Data structure and operations for quarantine queues. */
/*
* Each queue is a single-linked list, which also stores the total size of
* objects inside of it.
*/
struct qlist_head {
struct qlist_node *head;
struct qlist_node *tail;
size_t bytes;
bool offline;
};
#define QLIST_INIT { NULL, NULL, 0 }
static bool qlist_empty(struct qlist_head *q)
{
return !q->head;
}
static void qlist_init(struct qlist_head *q)
{
q->head = q->tail = NULL;
q->bytes = 0;
}
static void qlist_put(struct qlist_head *q, struct qlist_node *qlink,
size_t size)
{
if (unlikely(qlist_empty(q)))
q->head = qlink;
else
q->tail->next = qlink;
q->tail = qlink;
qlink->next = NULL;
q->bytes += size;
}
static void qlist_move_all(struct qlist_head *from, struct qlist_head *to)
{
if (unlikely(qlist_empty(from)))
return;
if (qlist_empty(to)) {
*to = *from;
qlist_init(from);
return;
}
to->tail->next = from->head;
to->tail = from->tail;
to->bytes += from->bytes;
qlist_init(from);
}
#define QUARANTINE_PERCPU_SIZE (1 << 20)
#define QUARANTINE_BATCHES \
(1024 > 4 * CONFIG_NR_CPUS ? 1024 : 4 * CONFIG_NR_CPUS)
/*
* The object quarantine consists of per-cpu queues and a global queue,
* guarded by quarantine_lock.
*/
static DEFINE_PER_CPU(struct qlist_head, cpu_quarantine);
/* Round-robin FIFO array of batches. */
static struct qlist_head global_quarantine[QUARANTINE_BATCHES];
static int quarantine_head;
static int quarantine_tail;
/* Total size of all objects in global_quarantine across all batches. */
static unsigned long quarantine_size;
static DEFINE_RAW_SPINLOCK(quarantine_lock);
DEFINE_STATIC_SRCU(remove_cache_srcu);
struct cpu_shrink_qlist {
raw_spinlock_t lock;
struct qlist_head qlist;
};
static DEFINE_PER_CPU(struct cpu_shrink_qlist, shrink_qlist) = {
.lock = __RAW_SPIN_LOCK_UNLOCKED(shrink_qlist.lock),
};
/* Maximum size of the global queue. */
static unsigned long quarantine_max_size;
/*
* Target size of a batch in global_quarantine.
* Usually equal to QUARANTINE_PERCPU_SIZE unless we have too much RAM.
*/
static unsigned long quarantine_batch_size;
/*
* The fraction of physical memory the quarantine is allowed to occupy.
* Quarantine doesn't support memory shrinker with SLAB allocator, so we keep
* the ratio low to avoid OOM.
*/
#define QUARANTINE_FRACTION 32
static struct kmem_cache *qlink_to_cache(struct qlist_node *qlink)
{
return virt_to_slab(qlink)->slab_cache;
}
static void *qlink_to_object(struct qlist_node *qlink, struct kmem_cache *cache)
{
struct kasan_free_meta *free_info =
container_of(qlink, struct kasan_free_meta,
quarantine_link);
return ((void *)free_info) - cache->kasan_info.free_meta_offset;
}
static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache)
{
void *object = qlink_to_object(qlink, cache);
struct kasan_free_meta *meta = kasan_get_free_meta(cache, object);
unsigned long flags;
if (IS_ENABLED(CONFIG_SLAB))
local_irq_save(flags);
/*
* If init_on_free is enabled and KASAN's free metadata is stored in
* the object, zero the metadata. Otherwise, the object's memory will
* not be properly zeroed, as KASAN saves the metadata after the slab
* allocator zeroes the object.
*/
if (slab_want_init_on_free(cache) &&
cache->kasan_info.free_meta_offset == 0)
memzero_explicit(meta, sizeof(*meta));
/*
* As the object now gets freed from the quarantine, assume that its
* free track is no longer valid.
*/
*(u8 *)kasan_mem_to_shadow(object) = KASAN_SLAB_FREE;
___cache_free(cache, object, _THIS_IP_);
if (IS_ENABLED(CONFIG_SLAB))
local_irq_restore(flags);
}
static void qlist_free_all(struct qlist_head *q, struct kmem_cache *cache)
{
struct qlist_node *qlink;
if (unlikely(qlist_empty(q)))
return;
qlink = q->head;
while (qlink) {
struct kmem_cache *obj_cache =
cache ? cache : qlink_to_cache(qlink);
struct qlist_node *next = qlink->next;
qlink_free(qlink, obj_cache);
qlink = next;
}
qlist_init(q);
}
bool kasan_quarantine_put(struct kmem_cache *cache, void *object)
{
unsigned long flags;
struct qlist_head *q;
struct qlist_head temp = QLIST_INIT;
struct kasan_free_meta *meta = kasan_get_free_meta(cache, object);
/*
* If there's no metadata for this object, don't put it into
* quarantine.
*/
if (!meta)
return false;
/*
* Note: irq must be disabled until after we move the batch to the
* global quarantine. Otherwise kasan_quarantine_remove_cache() can
* miss some objects belonging to the cache if they are in our local
* temp list. kasan_quarantine_remove_cache() executes on_each_cpu()
* at the beginning which ensures that it either sees the objects in
* per-cpu lists or in the global quarantine.
*/
local_irq_save(flags);
q = this_cpu_ptr(&cpu_quarantine);
if (q->offline) {
local_irq_restore(flags);
return false;
}
qlist_put(q, &meta->quarantine_link, cache->size);
if (unlikely(q->bytes > QUARANTINE_PERCPU_SIZE)) {
qlist_move_all(q, &temp);
raw_spin_lock(&quarantine_lock);
WRITE_ONCE(quarantine_size, quarantine_size + temp.bytes);
qlist_move_all(&temp, &global_quarantine[quarantine_tail]);
if (global_quarantine[quarantine_tail].bytes >=
READ_ONCE(quarantine_batch_size)) {
int new_tail;
new_tail = quarantine_tail + 1;
if (new_tail == QUARANTINE_BATCHES)
new_tail = 0;
if (new_tail != quarantine_head)
quarantine_tail = new_tail;
}
raw_spin_unlock(&quarantine_lock);
}
local_irq_restore(flags);
return true;
}
void kasan_quarantine_reduce(void)
{
size_t total_size, new_quarantine_size, percpu_quarantines;
unsigned long flags;
int srcu_idx;
struct qlist_head to_free = QLIST_INIT;
if (likely(READ_ONCE(quarantine_size) <=
READ_ONCE(quarantine_max_size)))
return;
/*
* srcu critical section ensures that kasan_quarantine_remove_cache()
* will not miss objects belonging to the cache while they are in our
* local to_free list. srcu is chosen because (1) it gives us private
* grace period domain that does not interfere with anything else,
* and (2) it allows synchronize_srcu() to return without waiting
* if there are no pending read critical sections (which is the
* expected case).
*/
srcu_idx = srcu_read_lock(&remove_cache_srcu);
raw_spin_lock_irqsave(&quarantine_lock, flags);
/*
* Update quarantine size in case of hotplug. Allocate a fraction of
* the installed memory to quarantine minus per-cpu queue limits.
*/
total_size = (totalram_pages() << PAGE_SHIFT) /
QUARANTINE_FRACTION;
percpu_quarantines = QUARANTINE_PERCPU_SIZE * num_online_cpus();
new_quarantine_size = (total_size < percpu_quarantines) ?
0 : total_size - percpu_quarantines;
WRITE_ONCE(quarantine_max_size, new_quarantine_size);
/* Aim at consuming at most 1/2 of slots in quarantine. */
WRITE_ONCE(quarantine_batch_size, max((size_t)QUARANTINE_PERCPU_SIZE,
2 * total_size / QUARANTINE_BATCHES));
if (likely(quarantine_size > quarantine_max_size)) {
qlist_move_all(&global_quarantine[quarantine_head], &to_free);
WRITE_ONCE(quarantine_size, quarantine_size - to_free.bytes);
quarantine_head++;
if (quarantine_head == QUARANTINE_BATCHES)
quarantine_head = 0;
}
raw_spin_unlock_irqrestore(&quarantine_lock, flags);
qlist_free_all(&to_free, NULL);
srcu_read_unlock(&remove_cache_srcu, srcu_idx);
}
static void qlist_move_cache(struct qlist_head *from,
struct qlist_head *to,
struct kmem_cache *cache)
{
struct qlist_node *curr;
if (unlikely(qlist_empty(from)))
return;
curr = from->head;
qlist_init(from);
while (curr) {
struct qlist_node *next = curr->next;
struct kmem_cache *obj_cache = qlink_to_cache(curr);
if (obj_cache == cache)
qlist_put(to, curr, obj_cache->size);
else
qlist_put(from, curr, obj_cache->size);
curr = next;
}
}
static void __per_cpu_remove_cache(struct qlist_head *q, void *arg)
{
struct kmem_cache *cache = arg;
unsigned long flags;
struct cpu_shrink_qlist *sq;
sq = this_cpu_ptr(&shrink_qlist);
raw_spin_lock_irqsave(&sq->lock, flags);
qlist_move_cache(q, &sq->qlist, cache);
raw_spin_unlock_irqrestore(&sq->lock, flags);
}
static void per_cpu_remove_cache(void *arg)
{
struct qlist_head *q;
q = this_cpu_ptr(&cpu_quarantine);
/*
* Ensure the ordering between the writing to q->offline and
* per_cpu_remove_cache. Prevent cpu_quarantine from being corrupted
* by interrupt.
*/
if (READ_ONCE(q->offline))
return;
__per_cpu_remove_cache(q, arg);
}
/* Free all quarantined objects belonging to cache. */
void kasan_quarantine_remove_cache(struct kmem_cache *cache)
{
unsigned long flags, i;
struct qlist_head to_free = QLIST_INIT;
int cpu;
struct cpu_shrink_qlist *sq;
/*
* Must be careful to not miss any objects that are being moved from
* per-cpu list to the global quarantine in kasan_quarantine_put(),
* nor objects being freed in kasan_quarantine_reduce(). on_each_cpu()
* achieves the first goal, while synchronize_srcu() achieves the
* second.
*/
on_each_cpu(per_cpu_remove_cache, cache, 1);
for_each_online_cpu(cpu) {
sq = per_cpu_ptr(&shrink_qlist, cpu);
raw_spin_lock_irqsave(&sq->lock, flags);
qlist_move_cache(&sq->qlist, &to_free, cache);
raw_spin_unlock_irqrestore(&sq->lock, flags);
}
qlist_free_all(&to_free, cache);
raw_spin_lock_irqsave(&quarantine_lock, flags);
for (i = 0; i < QUARANTINE_BATCHES; i++) {
if (qlist_empty(&global_quarantine[i]))
continue;
qlist_move_cache(&global_quarantine[i], &to_free, cache);
/* Scanning whole quarantine can take a while. */
raw_spin_unlock_irqrestore(&quarantine_lock, flags);
cond_resched();
raw_spin_lock_irqsave(&quarantine_lock, flags);
}
raw_spin_unlock_irqrestore(&quarantine_lock, flags);
qlist_free_all(&to_free, cache);
synchronize_srcu(&remove_cache_srcu);
}
static int kasan_cpu_online(unsigned int cpu)
{
this_cpu_ptr(&cpu_quarantine)->offline = false;
return 0;
}
static int kasan_cpu_offline(unsigned int cpu)
{
struct qlist_head *q;
q = this_cpu_ptr(&cpu_quarantine);
/* Ensure the ordering between the writing to q->offline and
* qlist_free_all. Otherwise, cpu_quarantine may be corrupted
* by interrupt.
*/
WRITE_ONCE(q->offline, true);
barrier();
qlist_free_all(q, NULL);
return 0;
}
static int __init kasan_cpu_quarantine_init(void)
{
int ret = 0;
ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "mm/kasan:online",
kasan_cpu_online, kasan_cpu_offline);
if (ret < 0)
pr_err("kasan cpu quarantine register failed [%d]\n", ret);
return ret;
}
late_initcall(kasan_cpu_quarantine_init);
| linux-master | mm/kasan/quarantine.c |
// SPDX-License-Identifier: GPL-2.0
/*
* This file contains core software tag-based KASAN code.
*
* Copyright (c) 2018 Google, Inc.
* Author: Andrey Konovalov <[email protected]>
*/
#define pr_fmt(fmt) "kasan: " fmt
#include <linux/export.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/kasan.h>
#include <linux/kernel.h>
#include <linux/kmemleak.h>
#include <linux/linkage.h>
#include <linux/memblock.h>
#include <linux/memory.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/printk.h>
#include <linux/random.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/slab.h>
#include <linux/stacktrace.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/vmalloc.h>
#include <linux/bug.h>
#include "kasan.h"
#include "../slab.h"
static DEFINE_PER_CPU(u32, prng_state);
void __init kasan_init_sw_tags(void)
{
int cpu;
for_each_possible_cpu(cpu)
per_cpu(prng_state, cpu) = (u32)get_cycles();
kasan_init_tags();
pr_info("KernelAddressSanitizer initialized (sw-tags, stacktrace=%s)\n",
kasan_stack_collection_enabled() ? "on" : "off");
}
/*
* If a preemption happens between this_cpu_read and this_cpu_write, the only
* side effect is that we'll give a few allocated in different contexts objects
* the same tag. Since tag-based KASAN is meant to be used a probabilistic
* bug-detection debug feature, this doesn't have significant negative impact.
*
* Ideally the tags use strong randomness to prevent any attempts to predict
* them during explicit exploit attempts. But strong randomness is expensive,
* and we did an intentional trade-off to use a PRNG. This non-atomic RMW
* sequence has in fact positive effect, since interrupts that randomly skew
* PRNG at unpredictable points do only good.
*/
u8 kasan_random_tag(void)
{
u32 state = this_cpu_read(prng_state);
state = 1664525 * state + 1013904223;
this_cpu_write(prng_state, state);
return (u8)(state % (KASAN_TAG_MAX + 1));
}
bool kasan_check_range(const void *addr, size_t size, bool write,
unsigned long ret_ip)
{
u8 tag;
u8 *shadow_first, *shadow_last, *shadow;
void *untagged_addr;
if (unlikely(size == 0))
return true;
if (unlikely(addr + size < addr))
return !kasan_report(addr, size, write, ret_ip);
tag = get_tag((const void *)addr);
/*
* Ignore accesses for pointers tagged with 0xff (native kernel
* pointer tag) to suppress false positives caused by kmap.
*
* Some kernel code was written to account for archs that don't keep
* high memory mapped all the time, but rather map and unmap particular
* pages when needed. Instead of storing a pointer to the kernel memory,
* this code saves the address of the page structure and offset within
* that page for later use. Those pages are then mapped and unmapped
* with kmap/kunmap when necessary and virt_to_page is used to get the
* virtual address of the page. For arm64 (that keeps the high memory
* mapped all the time), kmap is turned into a page_address call.
* The issue is that with use of the page_address + virt_to_page
* sequence the top byte value of the original pointer gets lost (gets
* set to KASAN_TAG_KERNEL (0xFF)).
*/
if (tag == KASAN_TAG_KERNEL)
return true;
untagged_addr = kasan_reset_tag((const void *)addr);
if (unlikely(!addr_has_metadata(untagged_addr)))
return !kasan_report(addr, size, write, ret_ip);
shadow_first = kasan_mem_to_shadow(untagged_addr);
shadow_last = kasan_mem_to_shadow(untagged_addr + size - 1);
for (shadow = shadow_first; shadow <= shadow_last; shadow++) {
if (*shadow != tag) {
return !kasan_report(addr, size, write, ret_ip);
}
}
return true;
}
bool kasan_byte_accessible(const void *addr)
{
u8 tag = get_tag(addr);
void *untagged_addr = kasan_reset_tag(addr);
u8 shadow_byte;
if (!addr_has_metadata(untagged_addr))
return false;
shadow_byte = READ_ONCE(*(u8 *)kasan_mem_to_shadow(untagged_addr));
return tag == KASAN_TAG_KERNEL || tag == shadow_byte;
}
#define DEFINE_HWASAN_LOAD_STORE(size) \
void __hwasan_load##size##_noabort(void *addr) \
{ \
kasan_check_range(addr, size, false, _RET_IP_); \
} \
EXPORT_SYMBOL(__hwasan_load##size##_noabort); \
void __hwasan_store##size##_noabort(void *addr) \
{ \
kasan_check_range(addr, size, true, _RET_IP_); \
} \
EXPORT_SYMBOL(__hwasan_store##size##_noabort)
DEFINE_HWASAN_LOAD_STORE(1);
DEFINE_HWASAN_LOAD_STORE(2);
DEFINE_HWASAN_LOAD_STORE(4);
DEFINE_HWASAN_LOAD_STORE(8);
DEFINE_HWASAN_LOAD_STORE(16);
void __hwasan_loadN_noabort(void *addr, ssize_t size)
{
kasan_check_range(addr, size, false, _RET_IP_);
}
EXPORT_SYMBOL(__hwasan_loadN_noabort);
void __hwasan_storeN_noabort(void *addr, ssize_t size)
{
kasan_check_range(addr, size, true, _RET_IP_);
}
EXPORT_SYMBOL(__hwasan_storeN_noabort);
void __hwasan_tag_memory(void *addr, u8 tag, ssize_t size)
{
kasan_poison(addr, size, tag, false);
}
EXPORT_SYMBOL(__hwasan_tag_memory);
void kasan_tag_mismatch(void *addr, unsigned long access_info,
unsigned long ret_ip)
{
kasan_report(addr, 1 << (access_info & 0xf), access_info & 0x10,
ret_ip);
}
| linux-master | mm/kasan/sw_tags.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2014 Samsung Electronics Co., Ltd.
* Copyright (c) 2020 Google, Inc.
*/
#include <linux/atomic.h>
#include "kasan.h"
extern struct kasan_stack_ring stack_ring;
static const char *get_common_bug_type(struct kasan_report_info *info)
{
/*
* If access_size is a negative number, then it has reason to be
* defined as out-of-bounds bug type.
*
* Casting negative numbers to size_t would indeed turn up as
* a large size_t and its value will be larger than ULONG_MAX/2,
* so that this can qualify as out-of-bounds.
*/
if (info->access_addr + info->access_size < info->access_addr)
return "out-of-bounds";
return "invalid-access";
}
void kasan_complete_mode_report_info(struct kasan_report_info *info)
{
unsigned long flags;
u64 pos;
struct kasan_stack_ring_entry *entry;
void *ptr;
u32 pid;
depot_stack_handle_t stack;
bool is_free;
bool alloc_found = false, free_found = false;
if ((!info->cache || !info->object) && !info->bug_type) {
info->bug_type = get_common_bug_type(info);
return;
}
write_lock_irqsave(&stack_ring.lock, flags);
pos = atomic64_read(&stack_ring.pos);
/*
* The loop below tries to find stack ring entries relevant to the
* buggy object. This is a best-effort process.
*
* First, another object with the same tag can be allocated in place of
* the buggy object. Also, since the number of entries is limited, the
* entries relevant to the buggy object can be overwritten.
*/
for (u64 i = pos - 1; i != pos - 1 - stack_ring.size; i--) {
if (alloc_found && free_found)
break;
entry = &stack_ring.entries[i % stack_ring.size];
/* Paired with smp_store_release() in save_stack_info(). */
ptr = (void *)smp_load_acquire(&entry->ptr);
if (kasan_reset_tag(ptr) != info->object ||
get_tag(ptr) != get_tag(info->access_addr))
continue;
pid = READ_ONCE(entry->pid);
stack = READ_ONCE(entry->stack);
is_free = READ_ONCE(entry->is_free);
if (is_free) {
/*
* Second free of the same object.
* Give up on trying to find the alloc entry.
*/
if (free_found)
break;
info->free_track.pid = pid;
info->free_track.stack = stack;
free_found = true;
/*
* If a free entry is found first, the bug is likely
* a use-after-free.
*/
if (!info->bug_type)
info->bug_type = "slab-use-after-free";
} else {
/* Second alloc of the same object. Give up. */
if (alloc_found)
break;
info->alloc_track.pid = pid;
info->alloc_track.stack = stack;
alloc_found = true;
/*
* If an alloc entry is found first, the bug is likely
* an out-of-bounds.
*/
if (!info->bug_type)
info->bug_type = "slab-out-of-bounds";
}
}
write_unlock_irqrestore(&stack_ring.lock, flags);
/* Assign the common bug type if no entries were found. */
if (!info->bug_type)
info->bug_type = get_common_bug_type(info);
}
| linux-master | mm/kasan/report_tags.c |
// SPDX-License-Identifier: GPL-2.0
/*
* This file contains hardware tag-based KASAN specific error reporting code.
*
* Copyright (c) 2020 Google, Inc.
* Author: Andrey Konovalov <[email protected]>
*/
#include <linux/kasan.h>
#include <linux/kernel.h>
#include <linux/memory.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/types.h>
#include "kasan.h"
const void *kasan_find_first_bad_addr(const void *addr, size_t size)
{
/*
* Hardware Tag-Based KASAN only calls this function for normal memory
* accesses, and thus addr points precisely to the first bad address
* with an invalid (and present) memory tag. Therefore:
* 1. Return the address as is without walking memory tags.
* 2. Skip the addr_has_metadata check.
*/
return kasan_reset_tag(addr);
}
size_t kasan_get_alloc_size(void *object, struct kmem_cache *cache)
{
size_t size = 0;
int i = 0;
u8 memory_tag;
/*
* Skip the addr_has_metadata check, as this function only operates on
* slab memory, which must have metadata.
*/
/*
* The loop below returns 0 for freed objects, for which KASAN cannot
* calculate the allocation size based on the metadata.
*/
while (size < cache->object_size) {
memory_tag = hw_get_mem_tag(object + i * KASAN_GRANULE_SIZE);
if (memory_tag != KASAN_TAG_INVALID)
size += KASAN_GRANULE_SIZE;
else
return size;
i++;
}
return cache->object_size;
}
void kasan_metadata_fetch_row(char *buffer, void *row)
{
int i;
for (i = 0; i < META_BYTES_PER_ROW; i++)
buffer[i] = hw_get_mem_tag(row + i * KASAN_GRANULE_SIZE);
}
void kasan_print_tags(u8 addr_tag, const void *addr)
{
u8 memory_tag = hw_get_mem_tag((void *)addr);
pr_err("Pointer tag: [%02x], memory tag: [%02x]\n",
addr_tag, memory_tag);
}
| linux-master | mm/kasan/report_hw_tags.c |
// SPDX-License-Identifier: GPL-2.0
/*
* This file contains core generic KASAN code.
*
* Copyright (c) 2014 Samsung Electronics Co., Ltd.
* Author: Andrey Ryabinin <[email protected]>
*
* Some code borrowed from https://github.com/xairy/kasan-prototype by
* Andrey Konovalov <[email protected]>
*/
#include <linux/export.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/kasan.h>
#include <linux/kernel.h>
#include <linux/kfence.h>
#include <linux/kmemleak.h>
#include <linux/linkage.h>
#include <linux/memblock.h>
#include <linux/memory.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/printk.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/slab.h>
#include <linux/stacktrace.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/vmalloc.h>
#include <linux/bug.h>
#include "kasan.h"
#include "../slab.h"
/*
* All functions below always inlined so compiler could
* perform better optimizations in each of __asan_loadX/__assn_storeX
* depending on memory access size X.
*/
static __always_inline bool memory_is_poisoned_1(const void *addr)
{
s8 shadow_value = *(s8 *)kasan_mem_to_shadow(addr);
if (unlikely(shadow_value)) {
s8 last_accessible_byte = (unsigned long)addr & KASAN_GRANULE_MASK;
return unlikely(last_accessible_byte >= shadow_value);
}
return false;
}
static __always_inline bool memory_is_poisoned_2_4_8(const void *addr,
unsigned long size)
{
u8 *shadow_addr = (u8 *)kasan_mem_to_shadow(addr);
/*
* Access crosses 8(shadow size)-byte boundary. Such access maps
* into 2 shadow bytes, so we need to check them both.
*/
if (unlikely((((unsigned long)addr + size - 1) & KASAN_GRANULE_MASK) < size - 1))
return *shadow_addr || memory_is_poisoned_1(addr + size - 1);
return memory_is_poisoned_1(addr + size - 1);
}
static __always_inline bool memory_is_poisoned_16(const void *addr)
{
u16 *shadow_addr = (u16 *)kasan_mem_to_shadow(addr);
/* Unaligned 16-bytes access maps into 3 shadow bytes. */
if (unlikely(!IS_ALIGNED((unsigned long)addr, KASAN_GRANULE_SIZE)))
return *shadow_addr || memory_is_poisoned_1(addr + 15);
return *shadow_addr;
}
static __always_inline unsigned long bytes_is_nonzero(const u8 *start,
size_t size)
{
while (size) {
if (unlikely(*start))
return (unsigned long)start;
start++;
size--;
}
return 0;
}
static __always_inline unsigned long memory_is_nonzero(const void *start,
const void *end)
{
unsigned int words;
unsigned long ret;
unsigned int prefix = (unsigned long)start % 8;
if (end - start <= 16)
return bytes_is_nonzero(start, end - start);
if (prefix) {
prefix = 8 - prefix;
ret = bytes_is_nonzero(start, prefix);
if (unlikely(ret))
return ret;
start += prefix;
}
words = (end - start) / 8;
while (words) {
if (unlikely(*(u64 *)start))
return bytes_is_nonzero(start, 8);
start += 8;
words--;
}
return bytes_is_nonzero(start, (end - start) % 8);
}
static __always_inline bool memory_is_poisoned_n(const void *addr, size_t size)
{
unsigned long ret;
ret = memory_is_nonzero(kasan_mem_to_shadow(addr),
kasan_mem_to_shadow(addr + size - 1) + 1);
if (unlikely(ret)) {
const void *last_byte = addr + size - 1;
s8 *last_shadow = (s8 *)kasan_mem_to_shadow(last_byte);
s8 last_accessible_byte = (unsigned long)last_byte & KASAN_GRANULE_MASK;
if (unlikely(ret != (unsigned long)last_shadow ||
last_accessible_byte >= *last_shadow))
return true;
}
return false;
}
static __always_inline bool memory_is_poisoned(const void *addr, size_t size)
{
if (__builtin_constant_p(size)) {
switch (size) {
case 1:
return memory_is_poisoned_1(addr);
case 2:
case 4:
case 8:
return memory_is_poisoned_2_4_8(addr, size);
case 16:
return memory_is_poisoned_16(addr);
default:
BUILD_BUG();
}
}
return memory_is_poisoned_n(addr, size);
}
static __always_inline bool check_region_inline(const void *addr,
size_t size, bool write,
unsigned long ret_ip)
{
if (!kasan_arch_is_ready())
return true;
if (unlikely(size == 0))
return true;
if (unlikely(addr + size < addr))
return !kasan_report(addr, size, write, ret_ip);
if (unlikely(!addr_has_metadata(addr)))
return !kasan_report(addr, size, write, ret_ip);
if (likely(!memory_is_poisoned(addr, size)))
return true;
return !kasan_report(addr, size, write, ret_ip);
}
bool kasan_check_range(const void *addr, size_t size, bool write,
unsigned long ret_ip)
{
return check_region_inline(addr, size, write, ret_ip);
}
bool kasan_byte_accessible(const void *addr)
{
s8 shadow_byte;
if (!kasan_arch_is_ready())
return true;
shadow_byte = READ_ONCE(*(s8 *)kasan_mem_to_shadow(addr));
return shadow_byte >= 0 && shadow_byte < KASAN_GRANULE_SIZE;
}
void kasan_cache_shrink(struct kmem_cache *cache)
{
kasan_quarantine_remove_cache(cache);
}
void kasan_cache_shutdown(struct kmem_cache *cache)
{
if (!__kmem_cache_empty(cache))
kasan_quarantine_remove_cache(cache);
}
static void register_global(struct kasan_global *global)
{
size_t aligned_size = round_up(global->size, KASAN_GRANULE_SIZE);
kasan_unpoison(global->beg, global->size, false);
kasan_poison(global->beg + aligned_size,
global->size_with_redzone - aligned_size,
KASAN_GLOBAL_REDZONE, false);
}
void __asan_register_globals(void *ptr, ssize_t size)
{
int i;
struct kasan_global *globals = ptr;
for (i = 0; i < size; i++)
register_global(&globals[i]);
}
EXPORT_SYMBOL(__asan_register_globals);
void __asan_unregister_globals(void *ptr, ssize_t size)
{
}
EXPORT_SYMBOL(__asan_unregister_globals);
#define DEFINE_ASAN_LOAD_STORE(size) \
void __asan_load##size(void *addr) \
{ \
check_region_inline(addr, size, false, _RET_IP_); \
} \
EXPORT_SYMBOL(__asan_load##size); \
__alias(__asan_load##size) \
void __asan_load##size##_noabort(void *); \
EXPORT_SYMBOL(__asan_load##size##_noabort); \
void __asan_store##size(void *addr) \
{ \
check_region_inline(addr, size, true, _RET_IP_); \
} \
EXPORT_SYMBOL(__asan_store##size); \
__alias(__asan_store##size) \
void __asan_store##size##_noabort(void *); \
EXPORT_SYMBOL(__asan_store##size##_noabort)
DEFINE_ASAN_LOAD_STORE(1);
DEFINE_ASAN_LOAD_STORE(2);
DEFINE_ASAN_LOAD_STORE(4);
DEFINE_ASAN_LOAD_STORE(8);
DEFINE_ASAN_LOAD_STORE(16);
void __asan_loadN(void *addr, ssize_t size)
{
kasan_check_range(addr, size, false, _RET_IP_);
}
EXPORT_SYMBOL(__asan_loadN);
__alias(__asan_loadN)
void __asan_loadN_noabort(void *, ssize_t);
EXPORT_SYMBOL(__asan_loadN_noabort);
void __asan_storeN(void *addr, ssize_t size)
{
kasan_check_range(addr, size, true, _RET_IP_);
}
EXPORT_SYMBOL(__asan_storeN);
__alias(__asan_storeN)
void __asan_storeN_noabort(void *, ssize_t);
EXPORT_SYMBOL(__asan_storeN_noabort);
/* to shut up compiler complaints */
void __asan_handle_no_return(void) {}
EXPORT_SYMBOL(__asan_handle_no_return);
/* Emitted by compiler to poison alloca()ed objects. */
void __asan_alloca_poison(void *addr, ssize_t size)
{
size_t rounded_up_size = round_up(size, KASAN_GRANULE_SIZE);
size_t padding_size = round_up(size, KASAN_ALLOCA_REDZONE_SIZE) -
rounded_up_size;
size_t rounded_down_size = round_down(size, KASAN_GRANULE_SIZE);
const void *left_redzone = (const void *)(addr -
KASAN_ALLOCA_REDZONE_SIZE);
const void *right_redzone = (const void *)(addr + rounded_up_size);
WARN_ON(!IS_ALIGNED((unsigned long)addr, KASAN_ALLOCA_REDZONE_SIZE));
kasan_unpoison((const void *)(addr + rounded_down_size),
size - rounded_down_size, false);
kasan_poison(left_redzone, KASAN_ALLOCA_REDZONE_SIZE,
KASAN_ALLOCA_LEFT, false);
kasan_poison(right_redzone, padding_size + KASAN_ALLOCA_REDZONE_SIZE,
KASAN_ALLOCA_RIGHT, false);
}
EXPORT_SYMBOL(__asan_alloca_poison);
/* Emitted by compiler to unpoison alloca()ed areas when the stack unwinds. */
void __asan_allocas_unpoison(void *stack_top, ssize_t stack_bottom)
{
if (unlikely(!stack_top || stack_top > (void *)stack_bottom))
return;
kasan_unpoison(stack_top, (void *)stack_bottom - stack_top, false);
}
EXPORT_SYMBOL(__asan_allocas_unpoison);
/* Emitted by the compiler to [un]poison local variables. */
#define DEFINE_ASAN_SET_SHADOW(byte) \
void __asan_set_shadow_##byte(const void *addr, ssize_t size) \
{ \
__memset((void *)addr, 0x##byte, size); \
} \
EXPORT_SYMBOL(__asan_set_shadow_##byte)
DEFINE_ASAN_SET_SHADOW(00);
DEFINE_ASAN_SET_SHADOW(f1);
DEFINE_ASAN_SET_SHADOW(f2);
DEFINE_ASAN_SET_SHADOW(f3);
DEFINE_ASAN_SET_SHADOW(f5);
DEFINE_ASAN_SET_SHADOW(f8);
/* Only allow cache merging when no per-object metadata is present. */
slab_flags_t kasan_never_merge(void)
{
if (!kasan_requires_meta())
return 0;
return SLAB_KASAN;
}
/*
* Adaptive redzone policy taken from the userspace AddressSanitizer runtime.
* For larger allocations larger redzones are used.
*/
static inline unsigned int optimal_redzone(unsigned int object_size)
{
return
object_size <= 64 - 16 ? 16 :
object_size <= 128 - 32 ? 32 :
object_size <= 512 - 64 ? 64 :
object_size <= 4096 - 128 ? 128 :
object_size <= (1 << 14) - 256 ? 256 :
object_size <= (1 << 15) - 512 ? 512 :
object_size <= (1 << 16) - 1024 ? 1024 : 2048;
}
void kasan_cache_create(struct kmem_cache *cache, unsigned int *size,
slab_flags_t *flags)
{
unsigned int ok_size;
unsigned int optimal_size;
if (!kasan_requires_meta())
return;
/*
* SLAB_KASAN is used to mark caches that are sanitized by KASAN
* and that thus have per-object metadata.
* Currently this flag is used in two places:
* 1. In slab_ksize() to account for per-object metadata when
* calculating the size of the accessible memory within the object.
* 2. In slab_common.c via kasan_never_merge() to prevent merging of
* caches with per-object metadata.
*/
*flags |= SLAB_KASAN;
ok_size = *size;
/* Add alloc meta into redzone. */
cache->kasan_info.alloc_meta_offset = *size;
*size += sizeof(struct kasan_alloc_meta);
/*
* If alloc meta doesn't fit, don't add it.
* This can only happen with SLAB, as it has KMALLOC_MAX_SIZE equal
* to KMALLOC_MAX_CACHE_SIZE and doesn't fall back to page_alloc for
* larger sizes.
*/
if (*size > KMALLOC_MAX_SIZE) {
cache->kasan_info.alloc_meta_offset = 0;
*size = ok_size;
/* Continue, since free meta might still fit. */
}
/*
* Add free meta into redzone when it's not possible to store
* it in the object. This is the case when:
* 1. Object is SLAB_TYPESAFE_BY_RCU, which means that it can
* be touched after it was freed, or
* 2. Object has a constructor, which means it's expected to
* retain its content until the next allocation, or
* 3. Object is too small.
* Otherwise cache->kasan_info.free_meta_offset = 0 is implied.
*/
if ((cache->flags & SLAB_TYPESAFE_BY_RCU) || cache->ctor ||
cache->object_size < sizeof(struct kasan_free_meta)) {
ok_size = *size;
cache->kasan_info.free_meta_offset = *size;
*size += sizeof(struct kasan_free_meta);
/* If free meta doesn't fit, don't add it. */
if (*size > KMALLOC_MAX_SIZE) {
cache->kasan_info.free_meta_offset = KASAN_NO_FREE_META;
*size = ok_size;
}
}
/* Calculate size with optimal redzone. */
optimal_size = cache->object_size + optimal_redzone(cache->object_size);
/* Limit it with KMALLOC_MAX_SIZE (relevant for SLAB only). */
if (optimal_size > KMALLOC_MAX_SIZE)
optimal_size = KMALLOC_MAX_SIZE;
/* Use optimal size if the size with added metas is not large enough. */
if (*size < optimal_size)
*size = optimal_size;
}
struct kasan_alloc_meta *kasan_get_alloc_meta(struct kmem_cache *cache,
const void *object)
{
if (!cache->kasan_info.alloc_meta_offset)
return NULL;
return (void *)object + cache->kasan_info.alloc_meta_offset;
}
struct kasan_free_meta *kasan_get_free_meta(struct kmem_cache *cache,
const void *object)
{
BUILD_BUG_ON(sizeof(struct kasan_free_meta) > 32);
if (cache->kasan_info.free_meta_offset == KASAN_NO_FREE_META)
return NULL;
return (void *)object + cache->kasan_info.free_meta_offset;
}
void kasan_init_object_meta(struct kmem_cache *cache, const void *object)
{
struct kasan_alloc_meta *alloc_meta;
alloc_meta = kasan_get_alloc_meta(cache, object);
if (alloc_meta)
__memset(alloc_meta, 0, sizeof(*alloc_meta));
}
size_t kasan_metadata_size(struct kmem_cache *cache, bool in_object)
{
struct kasan_cache *info = &cache->kasan_info;
if (!kasan_requires_meta())
return 0;
if (in_object)
return (info->free_meta_offset ?
0 : sizeof(struct kasan_free_meta));
else
return (info->alloc_meta_offset ?
sizeof(struct kasan_alloc_meta) : 0) +
((info->free_meta_offset &&
info->free_meta_offset != KASAN_NO_FREE_META) ?
sizeof(struct kasan_free_meta) : 0);
}
static void __kasan_record_aux_stack(void *addr, bool can_alloc)
{
struct slab *slab = kasan_addr_to_slab(addr);
struct kmem_cache *cache;
struct kasan_alloc_meta *alloc_meta;
void *object;
if (is_kfence_address(addr) || !slab)
return;
cache = slab->slab_cache;
object = nearest_obj(cache, slab, addr);
alloc_meta = kasan_get_alloc_meta(cache, object);
if (!alloc_meta)
return;
alloc_meta->aux_stack[1] = alloc_meta->aux_stack[0];
alloc_meta->aux_stack[0] = kasan_save_stack(0, can_alloc);
}
void kasan_record_aux_stack(void *addr)
{
return __kasan_record_aux_stack(addr, true);
}
void kasan_record_aux_stack_noalloc(void *addr)
{
return __kasan_record_aux_stack(addr, false);
}
void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags)
{
struct kasan_alloc_meta *alloc_meta;
alloc_meta = kasan_get_alloc_meta(cache, object);
if (alloc_meta)
kasan_set_track(&alloc_meta->alloc_track, flags);
}
void kasan_save_free_info(struct kmem_cache *cache, void *object)
{
struct kasan_free_meta *free_meta;
free_meta = kasan_get_free_meta(cache, object);
if (!free_meta)
return;
kasan_set_track(&free_meta->free_track, 0);
/* The object was freed and has free track set. */
*(u8 *)kasan_mem_to_shadow(object) = KASAN_SLAB_FREETRACK;
}
| linux-master | mm/kasan/generic.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
*
* Copyright (c) 2014 Samsung Electronics Co., Ltd.
* Author: Andrey Ryabinin <[email protected]>
*/
#define pr_fmt(fmt) "kasan_test: " fmt
#include <kunit/test.h>
#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/kasan.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/module.h>
#include <linux/printk.h>
#include <linux/random.h>
#include <linux/set_memory.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/tracepoint.h>
#include <linux/uaccess.h>
#include <linux/vmalloc.h>
#include <trace/events/printk.h>
#include <asm/page.h>
#include "kasan.h"
#define OOB_TAG_OFF (IS_ENABLED(CONFIG_KASAN_GENERIC) ? 0 : KASAN_GRANULE_SIZE)
static bool multishot;
/* Fields set based on lines observed in the console. */
static struct {
bool report_found;
bool async_fault;
} test_status;
/*
* Some tests use these global variables to store return values from function
* calls that could otherwise be eliminated by the compiler as dead code.
*/
void *kasan_ptr_result;
int kasan_int_result;
/* Probe for console output: obtains test_status lines of interest. */
static void probe_console(void *ignore, const char *buf, size_t len)
{
if (strnstr(buf, "BUG: KASAN: ", len))
WRITE_ONCE(test_status.report_found, true);
else if (strnstr(buf, "Asynchronous fault: ", len))
WRITE_ONCE(test_status.async_fault, true);
}
static int kasan_suite_init(struct kunit_suite *suite)
{
if (!kasan_enabled()) {
pr_err("Can't run KASAN tests with KASAN disabled");
return -1;
}
/* Stop failing KUnit tests on KASAN reports. */
kasan_kunit_test_suite_start();
/*
* Temporarily enable multi-shot mode. Otherwise, KASAN would only
* report the first detected bug and panic the kernel if panic_on_warn
* is enabled.
*/
multishot = kasan_save_enable_multi_shot();
register_trace_console(probe_console, NULL);
return 0;
}
static void kasan_suite_exit(struct kunit_suite *suite)
{
kasan_kunit_test_suite_end();
kasan_restore_multi_shot(multishot);
unregister_trace_console(probe_console, NULL);
tracepoint_synchronize_unregister();
}
static void kasan_test_exit(struct kunit *test)
{
KUNIT_EXPECT_FALSE(test, READ_ONCE(test_status.report_found));
}
/**
* KUNIT_EXPECT_KASAN_FAIL() - check that the executed expression produces a
* KASAN report; causes a test failure otherwise. This relies on a KUnit
* resource named "kasan_status". Do not use this name for KUnit resources
* outside of KASAN tests.
*
* For hardware tag-based KASAN, when a synchronous tag fault happens, tag
* checking is auto-disabled. When this happens, this test handler reenables
* tag checking. As tag checking can be only disabled or enabled per CPU,
* this handler disables migration (preemption).
*
* Since the compiler doesn't see that the expression can change the test_status
* fields, it can reorder or optimize away the accesses to those fields.
* Use READ/WRITE_ONCE() for the accesses and compiler barriers around the
* expression to prevent that.
*
* In between KUNIT_EXPECT_KASAN_FAIL checks, test_status.report_found is kept
* as false. This allows detecting KASAN reports that happen outside of the
* checks by asserting !test_status.report_found at the start of
* KUNIT_EXPECT_KASAN_FAIL and in kasan_test_exit.
*/
#define KUNIT_EXPECT_KASAN_FAIL(test, expression) do { \
if (IS_ENABLED(CONFIG_KASAN_HW_TAGS) && \
kasan_sync_fault_possible()) \
migrate_disable(); \
KUNIT_EXPECT_FALSE(test, READ_ONCE(test_status.report_found)); \
barrier(); \
expression; \
barrier(); \
if (kasan_async_fault_possible()) \
kasan_force_async_fault(); \
if (!READ_ONCE(test_status.report_found)) { \
KUNIT_FAIL(test, KUNIT_SUBTEST_INDENT "KASAN failure " \
"expected in \"" #expression \
"\", but none occurred"); \
} \
if (IS_ENABLED(CONFIG_KASAN_HW_TAGS) && \
kasan_sync_fault_possible()) { \
if (READ_ONCE(test_status.report_found) && \
!READ_ONCE(test_status.async_fault)) \
kasan_enable_hw_tags(); \
migrate_enable(); \
} \
WRITE_ONCE(test_status.report_found, false); \
WRITE_ONCE(test_status.async_fault, false); \
} while (0)
#define KASAN_TEST_NEEDS_CONFIG_ON(test, config) do { \
if (!IS_ENABLED(config)) \
kunit_skip((test), "Test requires " #config "=y"); \
} while (0)
#define KASAN_TEST_NEEDS_CONFIG_OFF(test, config) do { \
if (IS_ENABLED(config)) \
kunit_skip((test), "Test requires " #config "=n"); \
} while (0)
#define KASAN_TEST_NEEDS_CHECKED_MEMINTRINSICS(test) do { \
if (IS_ENABLED(CONFIG_KASAN_HW_TAGS)) \
break; /* No compiler instrumentation. */ \
if (IS_ENABLED(CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX)) \
break; /* Should always be instrumented! */ \
if (IS_ENABLED(CONFIG_GENERIC_ENTRY)) \
kunit_skip((test), "Test requires checked mem*()"); \
} while (0)
static void kmalloc_oob_right(struct kunit *test)
{
char *ptr;
size_t size = 128 - KASAN_GRANULE_SIZE - 5;
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
OPTIMIZER_HIDE_VAR(ptr);
/*
* An unaligned access past the requested kmalloc size.
* Only generic KASAN can precisely detect these.
*/
if (IS_ENABLED(CONFIG_KASAN_GENERIC))
KUNIT_EXPECT_KASAN_FAIL(test, ptr[size] = 'x');
/*
* An aligned access into the first out-of-bounds granule that falls
* within the aligned kmalloc object.
*/
KUNIT_EXPECT_KASAN_FAIL(test, ptr[size + 5] = 'y');
/* Out-of-bounds access past the aligned kmalloc object. */
KUNIT_EXPECT_KASAN_FAIL(test, ptr[0] =
ptr[size + KASAN_GRANULE_SIZE + 5]);
kfree(ptr);
}
static void kmalloc_oob_left(struct kunit *test)
{
char *ptr;
size_t size = 15;
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
OPTIMIZER_HIDE_VAR(ptr);
KUNIT_EXPECT_KASAN_FAIL(test, *ptr = *(ptr - 1));
kfree(ptr);
}
static void kmalloc_node_oob_right(struct kunit *test)
{
char *ptr;
size_t size = 4096;
ptr = kmalloc_node(size, GFP_KERNEL, 0);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
OPTIMIZER_HIDE_VAR(ptr);
KUNIT_EXPECT_KASAN_FAIL(test, ptr[0] = ptr[size]);
kfree(ptr);
}
/*
* These kmalloc_pagealloc_* tests try allocating a memory chunk that doesn't
* fit into a slab cache and therefore is allocated via the page allocator
* fallback. Since this kind of fallback is only implemented for SLUB, these
* tests are limited to that allocator.
*/
static void kmalloc_pagealloc_oob_right(struct kunit *test)
{
char *ptr;
size_t size = KMALLOC_MAX_CACHE_SIZE + 10;
KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_SLUB);
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
OPTIMIZER_HIDE_VAR(ptr);
KUNIT_EXPECT_KASAN_FAIL(test, ptr[size + OOB_TAG_OFF] = 0);
kfree(ptr);
}
static void kmalloc_pagealloc_uaf(struct kunit *test)
{
char *ptr;
size_t size = KMALLOC_MAX_CACHE_SIZE + 10;
KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_SLUB);
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
kfree(ptr);
KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[0]);
}
static void kmalloc_pagealloc_invalid_free(struct kunit *test)
{
char *ptr;
size_t size = KMALLOC_MAX_CACHE_SIZE + 10;
KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_SLUB);
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
KUNIT_EXPECT_KASAN_FAIL(test, kfree(ptr + 1));
}
static void pagealloc_oob_right(struct kunit *test)
{
char *ptr;
struct page *pages;
size_t order = 4;
size_t size = (1UL << (PAGE_SHIFT + order));
/*
* With generic KASAN page allocations have no redzones, thus
* out-of-bounds detection is not guaranteed.
* See https://bugzilla.kernel.org/show_bug.cgi?id=210503.
*/
KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_GENERIC);
pages = alloc_pages(GFP_KERNEL, order);
ptr = page_address(pages);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
KUNIT_EXPECT_KASAN_FAIL(test, ptr[0] = ptr[size]);
free_pages((unsigned long)ptr, order);
}
static void pagealloc_uaf(struct kunit *test)
{
char *ptr;
struct page *pages;
size_t order = 4;
pages = alloc_pages(GFP_KERNEL, order);
ptr = page_address(pages);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
free_pages((unsigned long)ptr, order);
KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[0]);
}
static void kmalloc_large_oob_right(struct kunit *test)
{
char *ptr;
size_t size = KMALLOC_MAX_CACHE_SIZE - 256;
/*
* Allocate a chunk that is large enough, but still fits into a slab
* and does not trigger the page allocator fallback in SLUB.
*/
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
OPTIMIZER_HIDE_VAR(ptr);
KUNIT_EXPECT_KASAN_FAIL(test, ptr[size] = 0);
kfree(ptr);
}
static void krealloc_more_oob_helper(struct kunit *test,
size_t size1, size_t size2)
{
char *ptr1, *ptr2;
size_t middle;
KUNIT_ASSERT_LT(test, size1, size2);
middle = size1 + (size2 - size1) / 2;
ptr1 = kmalloc(size1, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1);
ptr2 = krealloc(ptr1, size2, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr2);
/* Suppress -Warray-bounds warnings. */
OPTIMIZER_HIDE_VAR(ptr2);
/* All offsets up to size2 must be accessible. */
ptr2[size1 - 1] = 'x';
ptr2[size1] = 'x';
ptr2[middle] = 'x';
ptr2[size2 - 1] = 'x';
/* Generic mode is precise, so unaligned size2 must be inaccessible. */
if (IS_ENABLED(CONFIG_KASAN_GENERIC))
KUNIT_EXPECT_KASAN_FAIL(test, ptr2[size2] = 'x');
/* For all modes first aligned offset after size2 must be inaccessible. */
KUNIT_EXPECT_KASAN_FAIL(test,
ptr2[round_up(size2, KASAN_GRANULE_SIZE)] = 'x');
kfree(ptr2);
}
static void krealloc_less_oob_helper(struct kunit *test,
size_t size1, size_t size2)
{
char *ptr1, *ptr2;
size_t middle;
KUNIT_ASSERT_LT(test, size2, size1);
middle = size2 + (size1 - size2) / 2;
ptr1 = kmalloc(size1, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1);
ptr2 = krealloc(ptr1, size2, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr2);
/* Suppress -Warray-bounds warnings. */
OPTIMIZER_HIDE_VAR(ptr2);
/* Must be accessible for all modes. */
ptr2[size2 - 1] = 'x';
/* Generic mode is precise, so unaligned size2 must be inaccessible. */
if (IS_ENABLED(CONFIG_KASAN_GENERIC))
KUNIT_EXPECT_KASAN_FAIL(test, ptr2[size2] = 'x');
/* For all modes first aligned offset after size2 must be inaccessible. */
KUNIT_EXPECT_KASAN_FAIL(test,
ptr2[round_up(size2, KASAN_GRANULE_SIZE)] = 'x');
/*
* For all modes all size2, middle, and size1 should land in separate
* granules and thus the latter two offsets should be inaccessible.
*/
KUNIT_EXPECT_LE(test, round_up(size2, KASAN_GRANULE_SIZE),
round_down(middle, KASAN_GRANULE_SIZE));
KUNIT_EXPECT_LE(test, round_up(middle, KASAN_GRANULE_SIZE),
round_down(size1, KASAN_GRANULE_SIZE));
KUNIT_EXPECT_KASAN_FAIL(test, ptr2[middle] = 'x');
KUNIT_EXPECT_KASAN_FAIL(test, ptr2[size1 - 1] = 'x');
KUNIT_EXPECT_KASAN_FAIL(test, ptr2[size1] = 'x');
kfree(ptr2);
}
static void krealloc_more_oob(struct kunit *test)
{
krealloc_more_oob_helper(test, 201, 235);
}
static void krealloc_less_oob(struct kunit *test)
{
krealloc_less_oob_helper(test, 235, 201);
}
static void krealloc_pagealloc_more_oob(struct kunit *test)
{
/* page_alloc fallback in only implemented for SLUB. */
KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_SLUB);
krealloc_more_oob_helper(test, KMALLOC_MAX_CACHE_SIZE + 201,
KMALLOC_MAX_CACHE_SIZE + 235);
}
static void krealloc_pagealloc_less_oob(struct kunit *test)
{
/* page_alloc fallback in only implemented for SLUB. */
KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_SLUB);
krealloc_less_oob_helper(test, KMALLOC_MAX_CACHE_SIZE + 235,
KMALLOC_MAX_CACHE_SIZE + 201);
}
/*
* Check that krealloc() detects a use-after-free, returns NULL,
* and doesn't unpoison the freed object.
*/
static void krealloc_uaf(struct kunit *test)
{
char *ptr1, *ptr2;
int size1 = 201;
int size2 = 235;
ptr1 = kmalloc(size1, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1);
kfree(ptr1);
KUNIT_EXPECT_KASAN_FAIL(test, ptr2 = krealloc(ptr1, size2, GFP_KERNEL));
KUNIT_ASSERT_NULL(test, ptr2);
KUNIT_EXPECT_KASAN_FAIL(test, *(volatile char *)ptr1);
}
static void kmalloc_oob_16(struct kunit *test)
{
struct {
u64 words[2];
} *ptr1, *ptr2;
KASAN_TEST_NEEDS_CHECKED_MEMINTRINSICS(test);
/* This test is specifically crafted for the generic mode. */
KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC);
ptr1 = kmalloc(sizeof(*ptr1) - 3, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1);
ptr2 = kmalloc(sizeof(*ptr2), GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr2);
OPTIMIZER_HIDE_VAR(ptr1);
OPTIMIZER_HIDE_VAR(ptr2);
KUNIT_EXPECT_KASAN_FAIL(test, *ptr1 = *ptr2);
kfree(ptr1);
kfree(ptr2);
}
static void kmalloc_uaf_16(struct kunit *test)
{
struct {
u64 words[2];
} *ptr1, *ptr2;
KASAN_TEST_NEEDS_CHECKED_MEMINTRINSICS(test);
ptr1 = kmalloc(sizeof(*ptr1), GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1);
ptr2 = kmalloc(sizeof(*ptr2), GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr2);
kfree(ptr2);
KUNIT_EXPECT_KASAN_FAIL(test, *ptr1 = *ptr2);
kfree(ptr1);
}
/*
* Note: in the memset tests below, the written range touches both valid and
* invalid memory. This makes sure that the instrumentation does not only check
* the starting address but the whole range.
*/
static void kmalloc_oob_memset_2(struct kunit *test)
{
char *ptr;
size_t size = 128 - KASAN_GRANULE_SIZE;
KASAN_TEST_NEEDS_CHECKED_MEMINTRINSICS(test);
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
OPTIMIZER_HIDE_VAR(size);
KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + size - 1, 0, 2));
kfree(ptr);
}
static void kmalloc_oob_memset_4(struct kunit *test)
{
char *ptr;
size_t size = 128 - KASAN_GRANULE_SIZE;
KASAN_TEST_NEEDS_CHECKED_MEMINTRINSICS(test);
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
OPTIMIZER_HIDE_VAR(size);
KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + size - 3, 0, 4));
kfree(ptr);
}
static void kmalloc_oob_memset_8(struct kunit *test)
{
char *ptr;
size_t size = 128 - KASAN_GRANULE_SIZE;
KASAN_TEST_NEEDS_CHECKED_MEMINTRINSICS(test);
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
OPTIMIZER_HIDE_VAR(size);
KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + size - 7, 0, 8));
kfree(ptr);
}
static void kmalloc_oob_memset_16(struct kunit *test)
{
char *ptr;
size_t size = 128 - KASAN_GRANULE_SIZE;
KASAN_TEST_NEEDS_CHECKED_MEMINTRINSICS(test);
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
OPTIMIZER_HIDE_VAR(size);
KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + size - 15, 0, 16));
kfree(ptr);
}
static void kmalloc_oob_in_memset(struct kunit *test)
{
char *ptr;
size_t size = 128 - KASAN_GRANULE_SIZE;
KASAN_TEST_NEEDS_CHECKED_MEMINTRINSICS(test);
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
OPTIMIZER_HIDE_VAR(ptr);
OPTIMIZER_HIDE_VAR(size);
KUNIT_EXPECT_KASAN_FAIL(test,
memset(ptr, 0, size + KASAN_GRANULE_SIZE));
kfree(ptr);
}
static void kmalloc_memmove_negative_size(struct kunit *test)
{
char *ptr;
size_t size = 64;
size_t invalid_size = -2;
KASAN_TEST_NEEDS_CHECKED_MEMINTRINSICS(test);
/*
* Hardware tag-based mode doesn't check memmove for negative size.
* As a result, this test introduces a side-effect memory corruption,
* which can result in a crash.
*/
KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_HW_TAGS);
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
memset((char *)ptr, 0, 64);
OPTIMIZER_HIDE_VAR(ptr);
OPTIMIZER_HIDE_VAR(invalid_size);
KUNIT_EXPECT_KASAN_FAIL(test,
memmove((char *)ptr, (char *)ptr + 4, invalid_size));
kfree(ptr);
}
static void kmalloc_memmove_invalid_size(struct kunit *test)
{
char *ptr;
size_t size = 64;
size_t invalid_size = size;
KASAN_TEST_NEEDS_CHECKED_MEMINTRINSICS(test);
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
memset((char *)ptr, 0, 64);
OPTIMIZER_HIDE_VAR(ptr);
OPTIMIZER_HIDE_VAR(invalid_size);
KUNIT_EXPECT_KASAN_FAIL(test,
memmove((char *)ptr, (char *)ptr + 4, invalid_size));
kfree(ptr);
}
static void kmalloc_uaf(struct kunit *test)
{
char *ptr;
size_t size = 10;
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
kfree(ptr);
KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[8]);
}
static void kmalloc_uaf_memset(struct kunit *test)
{
char *ptr;
size_t size = 33;
KASAN_TEST_NEEDS_CHECKED_MEMINTRINSICS(test);
/*
* Only generic KASAN uses quarantine, which is required to avoid a
* kernel memory corruption this test causes.
*/
KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC);
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
kfree(ptr);
KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr, 0, size));
}
static void kmalloc_uaf2(struct kunit *test)
{
char *ptr1, *ptr2;
size_t size = 43;
int counter = 0;
again:
ptr1 = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1);
kfree(ptr1);
ptr2 = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr2);
/*
* For tag-based KASAN ptr1 and ptr2 tags might happen to be the same.
* Allow up to 16 attempts at generating different tags.
*/
if (!IS_ENABLED(CONFIG_KASAN_GENERIC) && ptr1 == ptr2 && counter++ < 16) {
kfree(ptr2);
goto again;
}
KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr1)[40]);
KUNIT_EXPECT_PTR_NE(test, ptr1, ptr2);
kfree(ptr2);
}
/*
* Check that KASAN detects use-after-free when another object was allocated in
* the same slot. Relevant for the tag-based modes, which do not use quarantine.
*/
static void kmalloc_uaf3(struct kunit *test)
{
char *ptr1, *ptr2;
size_t size = 100;
/* This test is specifically crafted for tag-based modes. */
KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_GENERIC);
ptr1 = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1);
kfree(ptr1);
ptr2 = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr2);
kfree(ptr2);
KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr1)[8]);
}
static void kfree_via_page(struct kunit *test)
{
char *ptr;
size_t size = 8;
struct page *page;
unsigned long offset;
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
page = virt_to_page(ptr);
offset = offset_in_page(ptr);
kfree(page_address(page) + offset);
}
static void kfree_via_phys(struct kunit *test)
{
char *ptr;
size_t size = 8;
phys_addr_t phys;
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
phys = virt_to_phys(ptr);
kfree(phys_to_virt(phys));
}
static void kmem_cache_oob(struct kunit *test)
{
char *p;
size_t size = 200;
struct kmem_cache *cache;
cache = kmem_cache_create("test_cache", size, 0, 0, NULL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, cache);
p = kmem_cache_alloc(cache, GFP_KERNEL);
if (!p) {
kunit_err(test, "Allocation failed: %s\n", __func__);
kmem_cache_destroy(cache);
return;
}
KUNIT_EXPECT_KASAN_FAIL(test, *p = p[size + OOB_TAG_OFF]);
kmem_cache_free(cache, p);
kmem_cache_destroy(cache);
}
static void kmem_cache_accounted(struct kunit *test)
{
int i;
char *p;
size_t size = 200;
struct kmem_cache *cache;
cache = kmem_cache_create("test_cache", size, 0, SLAB_ACCOUNT, NULL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, cache);
/*
* Several allocations with a delay to allow for lazy per memcg kmem
* cache creation.
*/
for (i = 0; i < 5; i++) {
p = kmem_cache_alloc(cache, GFP_KERNEL);
if (!p)
goto free_cache;
kmem_cache_free(cache, p);
msleep(100);
}
free_cache:
kmem_cache_destroy(cache);
}
static void kmem_cache_bulk(struct kunit *test)
{
struct kmem_cache *cache;
size_t size = 200;
char *p[10];
bool ret;
int i;
cache = kmem_cache_create("test_cache", size, 0, 0, NULL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, cache);
ret = kmem_cache_alloc_bulk(cache, GFP_KERNEL, ARRAY_SIZE(p), (void **)&p);
if (!ret) {
kunit_err(test, "Allocation failed: %s\n", __func__);
kmem_cache_destroy(cache);
return;
}
for (i = 0; i < ARRAY_SIZE(p); i++)
p[i][0] = p[i][size - 1] = 42;
kmem_cache_free_bulk(cache, ARRAY_SIZE(p), (void **)&p);
kmem_cache_destroy(cache);
}
static char global_array[10];
static void kasan_global_oob_right(struct kunit *test)
{
/*
* Deliberate out-of-bounds access. To prevent CONFIG_UBSAN_LOCAL_BOUNDS
* from failing here and panicking the kernel, access the array via a
* volatile pointer, which will prevent the compiler from being able to
* determine the array bounds.
*
* This access uses a volatile pointer to char (char *volatile) rather
* than the more conventional pointer to volatile char (volatile char *)
* because we want to prevent the compiler from making inferences about
* the pointer itself (i.e. its array bounds), not the data that it
* refers to.
*/
char *volatile array = global_array;
char *p = &array[ARRAY_SIZE(global_array) + 3];
/* Only generic mode instruments globals. */
KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC);
KUNIT_EXPECT_KASAN_FAIL(test, *(volatile char *)p);
}
static void kasan_global_oob_left(struct kunit *test)
{
char *volatile array = global_array;
char *p = array - 3;
/*
* GCC is known to fail this test, skip it.
* See https://bugzilla.kernel.org/show_bug.cgi?id=215051.
*/
KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_CC_IS_CLANG);
KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC);
KUNIT_EXPECT_KASAN_FAIL(test, *(volatile char *)p);
}
/* Check that ksize() does NOT unpoison whole object. */
static void ksize_unpoisons_memory(struct kunit *test)
{
char *ptr;
size_t size = 128 - KASAN_GRANULE_SIZE - 5;
size_t real_size;
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
real_size = ksize(ptr);
KUNIT_EXPECT_GT(test, real_size, size);
OPTIMIZER_HIDE_VAR(ptr);
/* These accesses shouldn't trigger a KASAN report. */
ptr[0] = 'x';
ptr[size - 1] = 'x';
/* These must trigger a KASAN report. */
if (IS_ENABLED(CONFIG_KASAN_GENERIC))
KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[size]);
KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[size + 5]);
KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[real_size - 1]);
kfree(ptr);
}
/*
* Check that a use-after-free is detected by ksize() and via normal accesses
* after it.
*/
static void ksize_uaf(struct kunit *test)
{
char *ptr;
int size = 128 - KASAN_GRANULE_SIZE;
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
kfree(ptr);
OPTIMIZER_HIDE_VAR(ptr);
KUNIT_EXPECT_KASAN_FAIL(test, ksize(ptr));
KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[0]);
KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[size]);
}
static void kasan_stack_oob(struct kunit *test)
{
char stack_array[10];
/* See comment in kasan_global_oob_right. */
char *volatile array = stack_array;
char *p = &array[ARRAY_SIZE(stack_array) + OOB_TAG_OFF];
KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_STACK);
KUNIT_EXPECT_KASAN_FAIL(test, *(volatile char *)p);
}
static void kasan_alloca_oob_left(struct kunit *test)
{
volatile int i = 10;
char alloca_array[i];
/* See comment in kasan_global_oob_right. */
char *volatile array = alloca_array;
char *p = array - 1;
/* Only generic mode instruments dynamic allocas. */
KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC);
KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_STACK);
KUNIT_EXPECT_KASAN_FAIL(test, *(volatile char *)p);
}
static void kasan_alloca_oob_right(struct kunit *test)
{
volatile int i = 10;
char alloca_array[i];
/* See comment in kasan_global_oob_right. */
char *volatile array = alloca_array;
char *p = array + i;
/* Only generic mode instruments dynamic allocas. */
KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC);
KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_STACK);
KUNIT_EXPECT_KASAN_FAIL(test, *(volatile char *)p);
}
static void kmem_cache_double_free(struct kunit *test)
{
char *p;
size_t size = 200;
struct kmem_cache *cache;
cache = kmem_cache_create("test_cache", size, 0, 0, NULL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, cache);
p = kmem_cache_alloc(cache, GFP_KERNEL);
if (!p) {
kunit_err(test, "Allocation failed: %s\n", __func__);
kmem_cache_destroy(cache);
return;
}
kmem_cache_free(cache, p);
KUNIT_EXPECT_KASAN_FAIL(test, kmem_cache_free(cache, p));
kmem_cache_destroy(cache);
}
static void kmem_cache_invalid_free(struct kunit *test)
{
char *p;
size_t size = 200;
struct kmem_cache *cache;
cache = kmem_cache_create("test_cache", size, 0, SLAB_TYPESAFE_BY_RCU,
NULL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, cache);
p = kmem_cache_alloc(cache, GFP_KERNEL);
if (!p) {
kunit_err(test, "Allocation failed: %s\n", __func__);
kmem_cache_destroy(cache);
return;
}
/* Trigger invalid free, the object doesn't get freed. */
KUNIT_EXPECT_KASAN_FAIL(test, kmem_cache_free(cache, p + 1));
/*
* Properly free the object to prevent the "Objects remaining in
* test_cache on __kmem_cache_shutdown" BUG failure.
*/
kmem_cache_free(cache, p);
kmem_cache_destroy(cache);
}
static void empty_cache_ctor(void *object) { }
static void kmem_cache_double_destroy(struct kunit *test)
{
struct kmem_cache *cache;
/* Provide a constructor to prevent cache merging. */
cache = kmem_cache_create("test_cache", 200, 0, 0, empty_cache_ctor);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, cache);
kmem_cache_destroy(cache);
KUNIT_EXPECT_KASAN_FAIL(test, kmem_cache_destroy(cache));
}
static void kasan_memchr(struct kunit *test)
{
char *ptr;
size_t size = 24;
/*
* str* functions are not instrumented with CONFIG_AMD_MEM_ENCRYPT.
* See https://bugzilla.kernel.org/show_bug.cgi?id=206337 for details.
*/
KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_AMD_MEM_ENCRYPT);
if (OOB_TAG_OFF)
size = round_up(size, OOB_TAG_OFF);
ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
OPTIMIZER_HIDE_VAR(ptr);
OPTIMIZER_HIDE_VAR(size);
KUNIT_EXPECT_KASAN_FAIL(test,
kasan_ptr_result = memchr(ptr, '1', size + 1));
kfree(ptr);
}
static void kasan_memcmp(struct kunit *test)
{
char *ptr;
size_t size = 24;
int arr[9];
/*
* str* functions are not instrumented with CONFIG_AMD_MEM_ENCRYPT.
* See https://bugzilla.kernel.org/show_bug.cgi?id=206337 for details.
*/
KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_AMD_MEM_ENCRYPT);
if (OOB_TAG_OFF)
size = round_up(size, OOB_TAG_OFF);
ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
memset(arr, 0, sizeof(arr));
OPTIMIZER_HIDE_VAR(ptr);
OPTIMIZER_HIDE_VAR(size);
KUNIT_EXPECT_KASAN_FAIL(test,
kasan_int_result = memcmp(ptr, arr, size+1));
kfree(ptr);
}
static void kasan_strings(struct kunit *test)
{
char *ptr;
size_t size = 24;
/*
* str* functions are not instrumented with CONFIG_AMD_MEM_ENCRYPT.
* See https://bugzilla.kernel.org/show_bug.cgi?id=206337 for details.
*/
KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_AMD_MEM_ENCRYPT);
ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
kfree(ptr);
/*
* Try to cause only 1 invalid access (less spam in dmesg).
* For that we need ptr to point to zeroed byte.
* Skip metadata that could be stored in freed object so ptr
* will likely point to zeroed byte.
*/
ptr += 16;
KUNIT_EXPECT_KASAN_FAIL(test, kasan_ptr_result = strchr(ptr, '1'));
KUNIT_EXPECT_KASAN_FAIL(test, kasan_ptr_result = strrchr(ptr, '1'));
KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = strcmp(ptr, "2"));
KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = strncmp(ptr, "2", 1));
KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = strlen(ptr));
KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = strnlen(ptr, 1));
}
static void kasan_bitops_modify(struct kunit *test, int nr, void *addr)
{
KUNIT_EXPECT_KASAN_FAIL(test, set_bit(nr, addr));
KUNIT_EXPECT_KASAN_FAIL(test, __set_bit(nr, addr));
KUNIT_EXPECT_KASAN_FAIL(test, clear_bit(nr, addr));
KUNIT_EXPECT_KASAN_FAIL(test, __clear_bit(nr, addr));
KUNIT_EXPECT_KASAN_FAIL(test, clear_bit_unlock(nr, addr));
KUNIT_EXPECT_KASAN_FAIL(test, __clear_bit_unlock(nr, addr));
KUNIT_EXPECT_KASAN_FAIL(test, change_bit(nr, addr));
KUNIT_EXPECT_KASAN_FAIL(test, __change_bit(nr, addr));
}
static void kasan_bitops_test_and_modify(struct kunit *test, int nr, void *addr)
{
KUNIT_EXPECT_KASAN_FAIL(test, test_and_set_bit(nr, addr));
KUNIT_EXPECT_KASAN_FAIL(test, __test_and_set_bit(nr, addr));
KUNIT_EXPECT_KASAN_FAIL(test, test_and_set_bit_lock(nr, addr));
KUNIT_EXPECT_KASAN_FAIL(test, test_and_clear_bit(nr, addr));
KUNIT_EXPECT_KASAN_FAIL(test, __test_and_clear_bit(nr, addr));
KUNIT_EXPECT_KASAN_FAIL(test, test_and_change_bit(nr, addr));
KUNIT_EXPECT_KASAN_FAIL(test, __test_and_change_bit(nr, addr));
KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = test_bit(nr, addr));
#if defined(clear_bit_unlock_is_negative_byte)
KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result =
clear_bit_unlock_is_negative_byte(nr, addr));
#endif
}
static void kasan_bitops_generic(struct kunit *test)
{
long *bits;
/* This test is specifically crafted for the generic mode. */
KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC);
/*
* Allocate 1 more byte, which causes kzalloc to round up to 16 bytes;
* this way we do not actually corrupt other memory.
*/
bits = kzalloc(sizeof(*bits) + 1, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, bits);
/*
* Below calls try to access bit within allocated memory; however, the
* below accesses are still out-of-bounds, since bitops are defined to
* operate on the whole long the bit is in.
*/
kasan_bitops_modify(test, BITS_PER_LONG, bits);
/*
* Below calls try to access bit beyond allocated memory.
*/
kasan_bitops_test_and_modify(test, BITS_PER_LONG + BITS_PER_BYTE, bits);
kfree(bits);
}
static void kasan_bitops_tags(struct kunit *test)
{
long *bits;
/* This test is specifically crafted for tag-based modes. */
KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_GENERIC);
/* kmalloc-64 cache will be used and the last 16 bytes will be the redzone. */
bits = kzalloc(48, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, bits);
/* Do the accesses past the 48 allocated bytes, but within the redone. */
kasan_bitops_modify(test, BITS_PER_LONG, (void *)bits + 48);
kasan_bitops_test_and_modify(test, BITS_PER_LONG + BITS_PER_BYTE, (void *)bits + 48);
kfree(bits);
}
static void kmalloc_double_kzfree(struct kunit *test)
{
char *ptr;
size_t size = 16;
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
kfree_sensitive(ptr);
KUNIT_EXPECT_KASAN_FAIL(test, kfree_sensitive(ptr));
}
/*
* The two tests below check that Generic KASAN prints auxiliary stack traces
* for RCU callbacks and workqueues. The reports need to be inspected manually.
*
* These tests are still enabled for other KASAN modes to make sure that all
* modes report bad accesses in tested scenarios.
*/
static struct kasan_rcu_info {
int i;
struct rcu_head rcu;
} *global_rcu_ptr;
static void rcu_uaf_reclaim(struct rcu_head *rp)
{
struct kasan_rcu_info *fp =
container_of(rp, struct kasan_rcu_info, rcu);
kfree(fp);
((volatile struct kasan_rcu_info *)fp)->i;
}
static void rcu_uaf(struct kunit *test)
{
struct kasan_rcu_info *ptr;
ptr = kmalloc(sizeof(struct kasan_rcu_info), GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
global_rcu_ptr = rcu_dereference_protected(
(struct kasan_rcu_info __rcu *)ptr, NULL);
KUNIT_EXPECT_KASAN_FAIL(test,
call_rcu(&global_rcu_ptr->rcu, rcu_uaf_reclaim);
rcu_barrier());
}
static void workqueue_uaf_work(struct work_struct *work)
{
kfree(work);
}
static void workqueue_uaf(struct kunit *test)
{
struct workqueue_struct *workqueue;
struct work_struct *work;
workqueue = create_workqueue("kasan_workqueue_test");
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, workqueue);
work = kmalloc(sizeof(struct work_struct), GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, work);
INIT_WORK(work, workqueue_uaf_work);
queue_work(workqueue, work);
destroy_workqueue(workqueue);
KUNIT_EXPECT_KASAN_FAIL(test,
((volatile struct work_struct *)work)->data);
}
static void vmalloc_helpers_tags(struct kunit *test)
{
void *ptr;
/* This test is intended for tag-based modes. */
KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_GENERIC);
KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_VMALLOC);
ptr = vmalloc(PAGE_SIZE);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
/* Check that the returned pointer is tagged. */
KUNIT_EXPECT_GE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_MIN);
KUNIT_EXPECT_LT(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL);
/* Make sure exported vmalloc helpers handle tagged pointers. */
KUNIT_ASSERT_TRUE(test, is_vmalloc_addr(ptr));
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, vmalloc_to_page(ptr));
#if !IS_MODULE(CONFIG_KASAN_KUNIT_TEST)
{
int rv;
/* Make sure vmalloc'ed memory permissions can be changed. */
rv = set_memory_ro((unsigned long)ptr, 1);
KUNIT_ASSERT_GE(test, rv, 0);
rv = set_memory_rw((unsigned long)ptr, 1);
KUNIT_ASSERT_GE(test, rv, 0);
}
#endif
vfree(ptr);
}
static void vmalloc_oob(struct kunit *test)
{
char *v_ptr, *p_ptr;
struct page *page;
size_t size = PAGE_SIZE / 2 - KASAN_GRANULE_SIZE - 5;
KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_VMALLOC);
v_ptr = vmalloc(size);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, v_ptr);
OPTIMIZER_HIDE_VAR(v_ptr);
/*
* We have to be careful not to hit the guard page in vmalloc tests.
* The MMU will catch that and crash us.
*/
/* Make sure in-bounds accesses are valid. */
v_ptr[0] = 0;
v_ptr[size - 1] = 0;
/*
* An unaligned access past the requested vmalloc size.
* Only generic KASAN can precisely detect these.
*/
if (IS_ENABLED(CONFIG_KASAN_GENERIC))
KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)v_ptr)[size]);
/* An aligned access into the first out-of-bounds granule. */
KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)v_ptr)[size + 5]);
/* Check that in-bounds accesses to the physical page are valid. */
page = vmalloc_to_page(v_ptr);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, page);
p_ptr = page_address(page);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, p_ptr);
p_ptr[0] = 0;
vfree(v_ptr);
/*
* We can't check for use-after-unmap bugs in this nor in the following
* vmalloc tests, as the page might be fully unmapped and accessing it
* will crash the kernel.
*/
}
static void vmap_tags(struct kunit *test)
{
char *p_ptr, *v_ptr;
struct page *p_page, *v_page;
/*
* This test is specifically crafted for the software tag-based mode,
* the only tag-based mode that poisons vmap mappings.
*/
KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_SW_TAGS);
KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_VMALLOC);
p_page = alloc_pages(GFP_KERNEL, 1);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, p_page);
p_ptr = page_address(p_page);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, p_ptr);
v_ptr = vmap(&p_page, 1, VM_MAP, PAGE_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, v_ptr);
/*
* We can't check for out-of-bounds bugs in this nor in the following
* vmalloc tests, as allocations have page granularity and accessing
* the guard page will crash the kernel.
*/
KUNIT_EXPECT_GE(test, (u8)get_tag(v_ptr), (u8)KASAN_TAG_MIN);
KUNIT_EXPECT_LT(test, (u8)get_tag(v_ptr), (u8)KASAN_TAG_KERNEL);
/* Make sure that in-bounds accesses through both pointers work. */
*p_ptr = 0;
*v_ptr = 0;
/* Make sure vmalloc_to_page() correctly recovers the page pointer. */
v_page = vmalloc_to_page(v_ptr);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, v_page);
KUNIT_EXPECT_PTR_EQ(test, p_page, v_page);
vunmap(v_ptr);
free_pages((unsigned long)p_ptr, 1);
}
static void vm_map_ram_tags(struct kunit *test)
{
char *p_ptr, *v_ptr;
struct page *page;
/*
* This test is specifically crafted for the software tag-based mode,
* the only tag-based mode that poisons vm_map_ram mappings.
*/
KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_SW_TAGS);
page = alloc_pages(GFP_KERNEL, 1);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, page);
p_ptr = page_address(page);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, p_ptr);
v_ptr = vm_map_ram(&page, 1, -1);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, v_ptr);
KUNIT_EXPECT_GE(test, (u8)get_tag(v_ptr), (u8)KASAN_TAG_MIN);
KUNIT_EXPECT_LT(test, (u8)get_tag(v_ptr), (u8)KASAN_TAG_KERNEL);
/* Make sure that in-bounds accesses through both pointers work. */
*p_ptr = 0;
*v_ptr = 0;
vm_unmap_ram(v_ptr, 1);
free_pages((unsigned long)p_ptr, 1);
}
static void vmalloc_percpu(struct kunit *test)
{
char __percpu *ptr;
int cpu;
/*
* This test is specifically crafted for the software tag-based mode,
* the only tag-based mode that poisons percpu mappings.
*/
KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_SW_TAGS);
ptr = __alloc_percpu(PAGE_SIZE, PAGE_SIZE);
for_each_possible_cpu(cpu) {
char *c_ptr = per_cpu_ptr(ptr, cpu);
KUNIT_EXPECT_GE(test, (u8)get_tag(c_ptr), (u8)KASAN_TAG_MIN);
KUNIT_EXPECT_LT(test, (u8)get_tag(c_ptr), (u8)KASAN_TAG_KERNEL);
/* Make sure that in-bounds accesses don't crash the kernel. */
*c_ptr = 0;
}
free_percpu(ptr);
}
/*
* Check that the assigned pointer tag falls within the [KASAN_TAG_MIN,
* KASAN_TAG_KERNEL) range (note: excluding the match-all tag) for tag-based
* modes.
*/
static void match_all_not_assigned(struct kunit *test)
{
char *ptr;
struct page *pages;
int i, size, order;
KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_GENERIC);
for (i = 0; i < 256; i++) {
size = get_random_u32_inclusive(1, 1024);
ptr = kmalloc(size, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
KUNIT_EXPECT_GE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_MIN);
KUNIT_EXPECT_LT(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL);
kfree(ptr);
}
for (i = 0; i < 256; i++) {
order = get_random_u32_inclusive(1, 4);
pages = alloc_pages(GFP_KERNEL, order);
ptr = page_address(pages);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
KUNIT_EXPECT_GE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_MIN);
KUNIT_EXPECT_LT(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL);
free_pages((unsigned long)ptr, order);
}
if (!IS_ENABLED(CONFIG_KASAN_VMALLOC))
return;
for (i = 0; i < 256; i++) {
size = get_random_u32_inclusive(1, 1024);
ptr = vmalloc(size);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
KUNIT_EXPECT_GE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_MIN);
KUNIT_EXPECT_LT(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL);
vfree(ptr);
}
}
/* Check that 0xff works as a match-all pointer tag for tag-based modes. */
static void match_all_ptr_tag(struct kunit *test)
{
char *ptr;
u8 tag;
KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_GENERIC);
ptr = kmalloc(128, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
/* Backup the assigned tag. */
tag = get_tag(ptr);
KUNIT_EXPECT_NE(test, tag, (u8)KASAN_TAG_KERNEL);
/* Reset the tag to 0xff.*/
ptr = set_tag(ptr, KASAN_TAG_KERNEL);
/* This access shouldn't trigger a KASAN report. */
*ptr = 0;
/* Recover the pointer tag and free. */
ptr = set_tag(ptr, tag);
kfree(ptr);
}
/* Check that there are no match-all memory tags for tag-based modes. */
static void match_all_mem_tag(struct kunit *test)
{
char *ptr;
int tag;
KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_GENERIC);
ptr = kmalloc(128, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
KUNIT_EXPECT_NE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL);
/* For each possible tag value not matching the pointer tag. */
for (tag = KASAN_TAG_MIN; tag <= KASAN_TAG_KERNEL; tag++) {
if (tag == get_tag(ptr))
continue;
/* Mark the first memory granule with the chosen memory tag. */
kasan_poison(ptr, KASAN_GRANULE_SIZE, (u8)tag, false);
/* This access must cause a KASAN report. */
KUNIT_EXPECT_KASAN_FAIL(test, *ptr = 0);
}
/* Recover the memory tag and free. */
kasan_poison(ptr, KASAN_GRANULE_SIZE, get_tag(ptr), false);
kfree(ptr);
}
static struct kunit_case kasan_kunit_test_cases[] = {
KUNIT_CASE(kmalloc_oob_right),
KUNIT_CASE(kmalloc_oob_left),
KUNIT_CASE(kmalloc_node_oob_right),
KUNIT_CASE(kmalloc_pagealloc_oob_right),
KUNIT_CASE(kmalloc_pagealloc_uaf),
KUNIT_CASE(kmalloc_pagealloc_invalid_free),
KUNIT_CASE(pagealloc_oob_right),
KUNIT_CASE(pagealloc_uaf),
KUNIT_CASE(kmalloc_large_oob_right),
KUNIT_CASE(krealloc_more_oob),
KUNIT_CASE(krealloc_less_oob),
KUNIT_CASE(krealloc_pagealloc_more_oob),
KUNIT_CASE(krealloc_pagealloc_less_oob),
KUNIT_CASE(krealloc_uaf),
KUNIT_CASE(kmalloc_oob_16),
KUNIT_CASE(kmalloc_uaf_16),
KUNIT_CASE(kmalloc_oob_in_memset),
KUNIT_CASE(kmalloc_oob_memset_2),
KUNIT_CASE(kmalloc_oob_memset_4),
KUNIT_CASE(kmalloc_oob_memset_8),
KUNIT_CASE(kmalloc_oob_memset_16),
KUNIT_CASE(kmalloc_memmove_negative_size),
KUNIT_CASE(kmalloc_memmove_invalid_size),
KUNIT_CASE(kmalloc_uaf),
KUNIT_CASE(kmalloc_uaf_memset),
KUNIT_CASE(kmalloc_uaf2),
KUNIT_CASE(kmalloc_uaf3),
KUNIT_CASE(kfree_via_page),
KUNIT_CASE(kfree_via_phys),
KUNIT_CASE(kmem_cache_oob),
KUNIT_CASE(kmem_cache_accounted),
KUNIT_CASE(kmem_cache_bulk),
KUNIT_CASE(kasan_global_oob_right),
KUNIT_CASE(kasan_global_oob_left),
KUNIT_CASE(kasan_stack_oob),
KUNIT_CASE(kasan_alloca_oob_left),
KUNIT_CASE(kasan_alloca_oob_right),
KUNIT_CASE(ksize_unpoisons_memory),
KUNIT_CASE(ksize_uaf),
KUNIT_CASE(kmem_cache_double_free),
KUNIT_CASE(kmem_cache_invalid_free),
KUNIT_CASE(kmem_cache_double_destroy),
KUNIT_CASE(kasan_memchr),
KUNIT_CASE(kasan_memcmp),
KUNIT_CASE(kasan_strings),
KUNIT_CASE(kasan_bitops_generic),
KUNIT_CASE(kasan_bitops_tags),
KUNIT_CASE(kmalloc_double_kzfree),
KUNIT_CASE(rcu_uaf),
KUNIT_CASE(workqueue_uaf),
KUNIT_CASE(vmalloc_helpers_tags),
KUNIT_CASE(vmalloc_oob),
KUNIT_CASE(vmap_tags),
KUNIT_CASE(vm_map_ram_tags),
KUNIT_CASE(vmalloc_percpu),
KUNIT_CASE(match_all_not_assigned),
KUNIT_CASE(match_all_ptr_tag),
KUNIT_CASE(match_all_mem_tag),
{}
};
static struct kunit_suite kasan_kunit_test_suite = {
.name = "kasan",
.test_cases = kasan_kunit_test_cases,
.exit = kasan_test_exit,
.suite_init = kasan_suite_init,
.suite_exit = kasan_suite_exit,
};
kunit_test_suite(kasan_kunit_test_suite);
MODULE_LICENSE("GPL");
| linux-master | mm/kasan/kasan_test.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
*
* Copyright (c) 2014 Samsung Electronics Co., Ltd.
* Author: Andrey Ryabinin <[email protected]>
*/
#define pr_fmt(fmt) "kasan test: %s " fmt, __func__
#include <linux/mman.h>
#include <linux/module.h>
#include <linux/printk.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include "kasan.h"
static noinline void __init copy_user_test(void)
{
char *kmem;
char __user *usermem;
size_t size = 128 - KASAN_GRANULE_SIZE;
int __maybe_unused unused;
kmem = kmalloc(size, GFP_KERNEL);
if (!kmem)
return;
usermem = (char __user *)vm_mmap(NULL, 0, PAGE_SIZE,
PROT_READ | PROT_WRITE | PROT_EXEC,
MAP_ANONYMOUS | MAP_PRIVATE, 0);
if (IS_ERR(usermem)) {
pr_err("Failed to allocate user memory\n");
kfree(kmem);
return;
}
OPTIMIZER_HIDE_VAR(size);
pr_info("out-of-bounds in copy_from_user()\n");
unused = copy_from_user(kmem, usermem, size + 1);
pr_info("out-of-bounds in copy_to_user()\n");
unused = copy_to_user(usermem, kmem, size + 1);
pr_info("out-of-bounds in __copy_from_user()\n");
unused = __copy_from_user(kmem, usermem, size + 1);
pr_info("out-of-bounds in __copy_to_user()\n");
unused = __copy_to_user(usermem, kmem, size + 1);
pr_info("out-of-bounds in __copy_from_user_inatomic()\n");
unused = __copy_from_user_inatomic(kmem, usermem, size + 1);
pr_info("out-of-bounds in __copy_to_user_inatomic()\n");
unused = __copy_to_user_inatomic(usermem, kmem, size + 1);
pr_info("out-of-bounds in strncpy_from_user()\n");
unused = strncpy_from_user(kmem, usermem, size + 1);
vm_munmap((unsigned long)usermem, PAGE_SIZE);
kfree(kmem);
}
static int __init test_kasan_module_init(void)
{
/*
* Temporarily enable multi-shot mode. Otherwise, KASAN would only
* report the first detected bug and panic the kernel if panic_on_warn
* is enabled.
*/
bool multishot = kasan_save_enable_multi_shot();
copy_user_test();
kasan_restore_multi_shot(multishot);
return -EAGAIN;
}
module_init(test_kasan_module_init);
MODULE_LICENSE("GPL");
| linux-master | mm/kasan/kasan_test_module.c |
// SPDX-License-Identifier: GPL-2.0
/*
* This file contains core hardware tag-based KASAN code.
*
* Copyright (c) 2020 Google, Inc.
* Author: Andrey Konovalov <[email protected]>
*/
#define pr_fmt(fmt) "kasan: " fmt
#include <linux/init.h>
#include <linux/kasan.h>
#include <linux/kernel.h>
#include <linux/memory.h>
#include <linux/mm.h>
#include <linux/static_key.h>
#include <linux/string.h>
#include <linux/types.h>
#include "kasan.h"
enum kasan_arg {
KASAN_ARG_DEFAULT,
KASAN_ARG_OFF,
KASAN_ARG_ON,
};
enum kasan_arg_mode {
KASAN_ARG_MODE_DEFAULT,
KASAN_ARG_MODE_SYNC,
KASAN_ARG_MODE_ASYNC,
KASAN_ARG_MODE_ASYMM,
};
enum kasan_arg_vmalloc {
KASAN_ARG_VMALLOC_DEFAULT,
KASAN_ARG_VMALLOC_OFF,
KASAN_ARG_VMALLOC_ON,
};
static enum kasan_arg kasan_arg __ro_after_init;
static enum kasan_arg_mode kasan_arg_mode __ro_after_init;
static enum kasan_arg_vmalloc kasan_arg_vmalloc __initdata;
/*
* Whether KASAN is enabled at all.
* The value remains false until KASAN is initialized by kasan_init_hw_tags().
*/
DEFINE_STATIC_KEY_FALSE(kasan_flag_enabled);
EXPORT_SYMBOL(kasan_flag_enabled);
/*
* Whether the selected mode is synchronous, asynchronous, or asymmetric.
* Defaults to KASAN_MODE_SYNC.
*/
enum kasan_mode kasan_mode __ro_after_init;
EXPORT_SYMBOL_GPL(kasan_mode);
/* Whether to enable vmalloc tagging. */
DEFINE_STATIC_KEY_TRUE(kasan_flag_vmalloc);
#define PAGE_ALLOC_SAMPLE_DEFAULT 1
#define PAGE_ALLOC_SAMPLE_ORDER_DEFAULT 3
/*
* Sampling interval of page_alloc allocation (un)poisoning.
* Defaults to no sampling.
*/
unsigned long kasan_page_alloc_sample = PAGE_ALLOC_SAMPLE_DEFAULT;
/*
* Minimum order of page_alloc allocations to be affected by sampling.
* The default value is chosen to match both
* PAGE_ALLOC_COSTLY_ORDER and SKB_FRAG_PAGE_ORDER.
*/
unsigned int kasan_page_alloc_sample_order = PAGE_ALLOC_SAMPLE_ORDER_DEFAULT;
DEFINE_PER_CPU(long, kasan_page_alloc_skip);
/* kasan=off/on */
static int __init early_kasan_flag(char *arg)
{
if (!arg)
return -EINVAL;
if (!strcmp(arg, "off"))
kasan_arg = KASAN_ARG_OFF;
else if (!strcmp(arg, "on"))
kasan_arg = KASAN_ARG_ON;
else
return -EINVAL;
return 0;
}
early_param("kasan", early_kasan_flag);
/* kasan.mode=sync/async/asymm */
static int __init early_kasan_mode(char *arg)
{
if (!arg)
return -EINVAL;
if (!strcmp(arg, "sync"))
kasan_arg_mode = KASAN_ARG_MODE_SYNC;
else if (!strcmp(arg, "async"))
kasan_arg_mode = KASAN_ARG_MODE_ASYNC;
else if (!strcmp(arg, "asymm"))
kasan_arg_mode = KASAN_ARG_MODE_ASYMM;
else
return -EINVAL;
return 0;
}
early_param("kasan.mode", early_kasan_mode);
/* kasan.vmalloc=off/on */
static int __init early_kasan_flag_vmalloc(char *arg)
{
if (!arg)
return -EINVAL;
if (!strcmp(arg, "off"))
kasan_arg_vmalloc = KASAN_ARG_VMALLOC_OFF;
else if (!strcmp(arg, "on"))
kasan_arg_vmalloc = KASAN_ARG_VMALLOC_ON;
else
return -EINVAL;
return 0;
}
early_param("kasan.vmalloc", early_kasan_flag_vmalloc);
static inline const char *kasan_mode_info(void)
{
if (kasan_mode == KASAN_MODE_ASYNC)
return "async";
else if (kasan_mode == KASAN_MODE_ASYMM)
return "asymm";
else
return "sync";
}
/* kasan.page_alloc.sample=<sampling interval> */
static int __init early_kasan_flag_page_alloc_sample(char *arg)
{
int rv;
if (!arg)
return -EINVAL;
rv = kstrtoul(arg, 0, &kasan_page_alloc_sample);
if (rv)
return rv;
if (!kasan_page_alloc_sample || kasan_page_alloc_sample > LONG_MAX) {
kasan_page_alloc_sample = PAGE_ALLOC_SAMPLE_DEFAULT;
return -EINVAL;
}
return 0;
}
early_param("kasan.page_alloc.sample", early_kasan_flag_page_alloc_sample);
/* kasan.page_alloc.sample.order=<minimum page order> */
static int __init early_kasan_flag_page_alloc_sample_order(char *arg)
{
int rv;
if (!arg)
return -EINVAL;
rv = kstrtouint(arg, 0, &kasan_page_alloc_sample_order);
if (rv)
return rv;
if (kasan_page_alloc_sample_order > INT_MAX) {
kasan_page_alloc_sample_order = PAGE_ALLOC_SAMPLE_ORDER_DEFAULT;
return -EINVAL;
}
return 0;
}
early_param("kasan.page_alloc.sample.order", early_kasan_flag_page_alloc_sample_order);
/*
* kasan_init_hw_tags_cpu() is called for each CPU.
* Not marked as __init as a CPU can be hot-plugged after boot.
*/
void kasan_init_hw_tags_cpu(void)
{
/*
* There's no need to check that the hardware is MTE-capable here,
* as this function is only called for MTE-capable hardware.
*/
/*
* If KASAN is disabled via command line, don't initialize it.
* When this function is called, kasan_flag_enabled is not yet
* set by kasan_init_hw_tags(). Thus, check kasan_arg instead.
*/
if (kasan_arg == KASAN_ARG_OFF)
return;
/*
* Enable async or asymm modes only when explicitly requested
* through the command line.
*/
kasan_enable_hw_tags();
}
/* kasan_init_hw_tags() is called once on boot CPU. */
void __init kasan_init_hw_tags(void)
{
/* If hardware doesn't support MTE, don't initialize KASAN. */
if (!system_supports_mte())
return;
/* If KASAN is disabled via command line, don't initialize it. */
if (kasan_arg == KASAN_ARG_OFF)
return;
switch (kasan_arg_mode) {
case KASAN_ARG_MODE_DEFAULT:
/* Default is specified by kasan_mode definition. */
break;
case KASAN_ARG_MODE_SYNC:
kasan_mode = KASAN_MODE_SYNC;
break;
case KASAN_ARG_MODE_ASYNC:
kasan_mode = KASAN_MODE_ASYNC;
break;
case KASAN_ARG_MODE_ASYMM:
kasan_mode = KASAN_MODE_ASYMM;
break;
}
switch (kasan_arg_vmalloc) {
case KASAN_ARG_VMALLOC_DEFAULT:
/* Default is specified by kasan_flag_vmalloc definition. */
break;
case KASAN_ARG_VMALLOC_OFF:
static_branch_disable(&kasan_flag_vmalloc);
break;
case KASAN_ARG_VMALLOC_ON:
static_branch_enable(&kasan_flag_vmalloc);
break;
}
kasan_init_tags();
/* KASAN is now initialized, enable it. */
static_branch_enable(&kasan_flag_enabled);
pr_info("KernelAddressSanitizer initialized (hw-tags, mode=%s, vmalloc=%s, stacktrace=%s)\n",
kasan_mode_info(),
kasan_vmalloc_enabled() ? "on" : "off",
kasan_stack_collection_enabled() ? "on" : "off");
}
#ifdef CONFIG_KASAN_VMALLOC
static void unpoison_vmalloc_pages(const void *addr, u8 tag)
{
struct vm_struct *area;
int i;
/*
* As hardware tag-based KASAN only tags VM_ALLOC vmalloc allocations
* (see the comment in __kasan_unpoison_vmalloc), all of the pages
* should belong to a single area.
*/
area = find_vm_area((void *)addr);
if (WARN_ON(!area))
return;
for (i = 0; i < area->nr_pages; i++) {
struct page *page = area->pages[i];
page_kasan_tag_set(page, tag);
}
}
static void init_vmalloc_pages(const void *start, unsigned long size)
{
const void *addr;
for (addr = start; addr < start + size; addr += PAGE_SIZE) {
struct page *page = vmalloc_to_page(addr);
clear_highpage_kasan_tagged(page);
}
}
void *__kasan_unpoison_vmalloc(const void *start, unsigned long size,
kasan_vmalloc_flags_t flags)
{
u8 tag;
unsigned long redzone_start, redzone_size;
if (!kasan_vmalloc_enabled()) {
if (flags & KASAN_VMALLOC_INIT)
init_vmalloc_pages(start, size);
return (void *)start;
}
/*
* Don't tag non-VM_ALLOC mappings, as:
*
* 1. Unlike the software KASAN modes, hardware tag-based KASAN only
* supports tagging physical memory. Therefore, it can only tag a
* single mapping of normal physical pages.
* 2. Hardware tag-based KASAN can only tag memory mapped with special
* mapping protection bits, see arch_vmap_pgprot_tagged().
* As non-VM_ALLOC mappings can be mapped outside of vmalloc code,
* providing these bits would require tracking all non-VM_ALLOC
* mappers.
*
* Thus, for VM_ALLOC mappings, hardware tag-based KASAN only tags
* the first virtual mapping, which is created by vmalloc().
* Tagging the page_alloc memory backing that vmalloc() allocation is
* skipped, see ___GFP_SKIP_KASAN.
*
* For non-VM_ALLOC allocations, page_alloc memory is tagged as usual.
*/
if (!(flags & KASAN_VMALLOC_VM_ALLOC)) {
WARN_ON(flags & KASAN_VMALLOC_INIT);
return (void *)start;
}
/*
* Don't tag executable memory.
* The kernel doesn't tolerate having the PC register tagged.
*/
if (!(flags & KASAN_VMALLOC_PROT_NORMAL)) {
WARN_ON(flags & KASAN_VMALLOC_INIT);
return (void *)start;
}
tag = kasan_random_tag();
start = set_tag(start, tag);
/* Unpoison and initialize memory up to size. */
kasan_unpoison(start, size, flags & KASAN_VMALLOC_INIT);
/*
* Explicitly poison and initialize the in-page vmalloc() redzone.
* Unlike software KASAN modes, hardware tag-based KASAN doesn't
* unpoison memory when populating shadow for vmalloc() space.
*/
redzone_start = round_up((unsigned long)start + size,
KASAN_GRANULE_SIZE);
redzone_size = round_up(redzone_start, PAGE_SIZE) - redzone_start;
kasan_poison((void *)redzone_start, redzone_size, KASAN_TAG_INVALID,
flags & KASAN_VMALLOC_INIT);
/*
* Set per-page tag flags to allow accessing physical memory for the
* vmalloc() mapping through page_address(vmalloc_to_page()).
*/
unpoison_vmalloc_pages(start, tag);
return (void *)start;
}
void __kasan_poison_vmalloc(const void *start, unsigned long size)
{
/*
* No tagging here.
* The physical pages backing the vmalloc() allocation are poisoned
* through the usual page_alloc paths.
*/
}
#endif
void kasan_enable_hw_tags(void)
{
if (kasan_arg_mode == KASAN_ARG_MODE_ASYNC)
hw_enable_tag_checks_async();
else if (kasan_arg_mode == KASAN_ARG_MODE_ASYMM)
hw_enable_tag_checks_asymm();
else
hw_enable_tag_checks_sync();
}
#if IS_ENABLED(CONFIG_KASAN_KUNIT_TEST)
EXPORT_SYMBOL_GPL(kasan_enable_hw_tags);
void kasan_force_async_fault(void)
{
hw_force_async_tag_fault();
}
EXPORT_SYMBOL_GPL(kasan_force_async_fault);
#endif
| linux-master | mm/kasan/hw_tags.c |
// SPDX-License-Identifier: GPL-2.0
/*
* This file contains generic KASAN specific error reporting code.
*
* Copyright (c) 2014 Samsung Electronics Co., Ltd.
* Author: Andrey Ryabinin <[email protected]>
*
* Some code borrowed from https://github.com/xairy/kasan-prototype by
* Andrey Konovalov <[email protected]>
*/
#include <linux/bitops.h>
#include <linux/ftrace.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/printk.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/slab.h>
#include <linux/stackdepot.h>
#include <linux/stacktrace.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/kasan.h>
#include <linux/module.h>
#include <asm/sections.h>
#include "kasan.h"
#include "../slab.h"
const void *kasan_find_first_bad_addr(const void *addr, size_t size)
{
const void *p = addr;
if (!addr_has_metadata(p))
return p;
while (p < addr + size && !(*(u8 *)kasan_mem_to_shadow(p)))
p += KASAN_GRANULE_SIZE;
return p;
}
size_t kasan_get_alloc_size(void *object, struct kmem_cache *cache)
{
size_t size = 0;
u8 *shadow;
/*
* Skip the addr_has_metadata check, as this function only operates on
* slab memory, which must have metadata.
*/
/*
* The loop below returns 0 for freed objects, for which KASAN cannot
* calculate the allocation size based on the metadata.
*/
shadow = (u8 *)kasan_mem_to_shadow(object);
while (size < cache->object_size) {
if (*shadow == 0)
size += KASAN_GRANULE_SIZE;
else if (*shadow >= 1 && *shadow <= KASAN_GRANULE_SIZE - 1)
return size + *shadow;
else
return size;
shadow++;
}
return cache->object_size;
}
static const char *get_shadow_bug_type(struct kasan_report_info *info)
{
const char *bug_type = "unknown-crash";
u8 *shadow_addr;
shadow_addr = (u8 *)kasan_mem_to_shadow(info->first_bad_addr);
/*
* If shadow byte value is in [0, KASAN_GRANULE_SIZE) we can look
* at the next shadow byte to determine the type of the bad access.
*/
if (*shadow_addr > 0 && *shadow_addr <= KASAN_GRANULE_SIZE - 1)
shadow_addr++;
switch (*shadow_addr) {
case 0 ... KASAN_GRANULE_SIZE - 1:
/*
* In theory it's still possible to see these shadow values
* due to a data race in the kernel code.
*/
bug_type = "out-of-bounds";
break;
case KASAN_PAGE_REDZONE:
case KASAN_SLAB_REDZONE:
bug_type = "slab-out-of-bounds";
break;
case KASAN_GLOBAL_REDZONE:
bug_type = "global-out-of-bounds";
break;
case KASAN_STACK_LEFT:
case KASAN_STACK_MID:
case KASAN_STACK_RIGHT:
case KASAN_STACK_PARTIAL:
bug_type = "stack-out-of-bounds";
break;
case KASAN_PAGE_FREE:
bug_type = "use-after-free";
break;
case KASAN_SLAB_FREE:
case KASAN_SLAB_FREETRACK:
bug_type = "slab-use-after-free";
break;
case KASAN_ALLOCA_LEFT:
case KASAN_ALLOCA_RIGHT:
bug_type = "alloca-out-of-bounds";
break;
case KASAN_VMALLOC_INVALID:
bug_type = "vmalloc-out-of-bounds";
break;
}
return bug_type;
}
static const char *get_wild_bug_type(struct kasan_report_info *info)
{
const char *bug_type = "unknown-crash";
if ((unsigned long)info->access_addr < PAGE_SIZE)
bug_type = "null-ptr-deref";
else if ((unsigned long)info->access_addr < TASK_SIZE)
bug_type = "user-memory-access";
else
bug_type = "wild-memory-access";
return bug_type;
}
static const char *get_bug_type(struct kasan_report_info *info)
{
/*
* If access_size is a negative number, then it has reason to be
* defined as out-of-bounds bug type.
*
* Casting negative numbers to size_t would indeed turn up as
* a large size_t and its value will be larger than ULONG_MAX/2,
* so that this can qualify as out-of-bounds.
*/
if (info->access_addr + info->access_size < info->access_addr)
return "out-of-bounds";
if (addr_has_metadata(info->access_addr))
return get_shadow_bug_type(info);
return get_wild_bug_type(info);
}
void kasan_complete_mode_report_info(struct kasan_report_info *info)
{
struct kasan_alloc_meta *alloc_meta;
struct kasan_free_meta *free_meta;
if (!info->bug_type)
info->bug_type = get_bug_type(info);
if (!info->cache || !info->object)
return;
alloc_meta = kasan_get_alloc_meta(info->cache, info->object);
if (alloc_meta)
memcpy(&info->alloc_track, &alloc_meta->alloc_track,
sizeof(info->alloc_track));
if (*(u8 *)kasan_mem_to_shadow(info->object) == KASAN_SLAB_FREETRACK) {
/* Free meta must be present with KASAN_SLAB_FREETRACK. */
free_meta = kasan_get_free_meta(info->cache, info->object);
memcpy(&info->free_track, &free_meta->free_track,
sizeof(info->free_track));
}
}
void kasan_metadata_fetch_row(char *buffer, void *row)
{
memcpy(buffer, kasan_mem_to_shadow(row), META_BYTES_PER_ROW);
}
void kasan_print_aux_stacks(struct kmem_cache *cache, const void *object)
{
struct kasan_alloc_meta *alloc_meta;
alloc_meta = kasan_get_alloc_meta(cache, object);
if (!alloc_meta)
return;
if (alloc_meta->aux_stack[0]) {
pr_err("Last potentially related work creation:\n");
stack_depot_print(alloc_meta->aux_stack[0]);
pr_err("\n");
}
if (alloc_meta->aux_stack[1]) {
pr_err("Second to last potentially related work creation:\n");
stack_depot_print(alloc_meta->aux_stack[1]);
pr_err("\n");
}
}
#ifdef CONFIG_KASAN_STACK
static bool __must_check tokenize_frame_descr(const char **frame_descr,
char *token, size_t max_tok_len,
unsigned long *value)
{
const char *sep = strchr(*frame_descr, ' ');
if (sep == NULL)
sep = *frame_descr + strlen(*frame_descr);
if (token != NULL) {
const size_t tok_len = sep - *frame_descr;
if (tok_len + 1 > max_tok_len) {
pr_err("KASAN internal error: frame description too long: %s\n",
*frame_descr);
return false;
}
/* Copy token (+ 1 byte for '\0'). */
strscpy(token, *frame_descr, tok_len + 1);
}
/* Advance frame_descr past separator. */
*frame_descr = sep + 1;
if (value != NULL && kstrtoul(token, 10, value)) {
pr_err("KASAN internal error: not a valid number: %s\n", token);
return false;
}
return true;
}
static void print_decoded_frame_descr(const char *frame_descr)
{
/*
* We need to parse the following string:
* "n alloc_1 alloc_2 ... alloc_n"
* where alloc_i looks like
* "offset size len name"
* or "offset size len name:line".
*/
char token[64];
unsigned long num_objects;
if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
&num_objects))
return;
pr_err("\n");
pr_err("This frame has %lu %s:\n", num_objects,
num_objects == 1 ? "object" : "objects");
while (num_objects--) {
unsigned long offset;
unsigned long size;
/* access offset */
if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
&offset))
return;
/* access size */
if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
&size))
return;
/* name length (unused) */
if (!tokenize_frame_descr(&frame_descr, NULL, 0, NULL))
return;
/* object name */
if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
NULL))
return;
/* Strip line number; without filename it's not very helpful. */
strreplace(token, ':', '\0');
/* Finally, print object information. */
pr_err(" [%lu, %lu) '%s'", offset, offset + size, token);
}
}
/* Returns true only if the address is on the current task's stack. */
static bool __must_check get_address_stack_frame_info(const void *addr,
unsigned long *offset,
const char **frame_descr,
const void **frame_pc)
{
unsigned long aligned_addr;
unsigned long mem_ptr;
const u8 *shadow_bottom;
const u8 *shadow_ptr;
const unsigned long *frame;
BUILD_BUG_ON(IS_ENABLED(CONFIG_STACK_GROWSUP));
aligned_addr = round_down((unsigned long)addr, sizeof(long));
mem_ptr = round_down(aligned_addr, KASAN_GRANULE_SIZE);
shadow_ptr = kasan_mem_to_shadow((void *)aligned_addr);
shadow_bottom = kasan_mem_to_shadow(end_of_stack(current));
while (shadow_ptr >= shadow_bottom && *shadow_ptr != KASAN_STACK_LEFT) {
shadow_ptr--;
mem_ptr -= KASAN_GRANULE_SIZE;
}
while (shadow_ptr >= shadow_bottom && *shadow_ptr == KASAN_STACK_LEFT) {
shadow_ptr--;
mem_ptr -= KASAN_GRANULE_SIZE;
}
if (shadow_ptr < shadow_bottom)
return false;
frame = (const unsigned long *)(mem_ptr + KASAN_GRANULE_SIZE);
if (frame[0] != KASAN_CURRENT_STACK_FRAME_MAGIC) {
pr_err("KASAN internal error: frame info validation failed; invalid marker: %lu\n",
frame[0]);
return false;
}
*offset = (unsigned long)addr - (unsigned long)frame;
*frame_descr = (const char *)frame[1];
*frame_pc = (void *)frame[2];
return true;
}
void kasan_print_address_stack_frame(const void *addr)
{
unsigned long offset;
const char *frame_descr;
const void *frame_pc;
if (WARN_ON(!object_is_on_stack(addr)))
return;
pr_err("The buggy address belongs to stack of task %s/%d\n",
current->comm, task_pid_nr(current));
if (!get_address_stack_frame_info(addr, &offset, &frame_descr,
&frame_pc))
return;
pr_err(" and is located at offset %lu in frame:\n", offset);
pr_err(" %pS\n", frame_pc);
if (!frame_descr)
return;
print_decoded_frame_descr(frame_descr);
}
#endif /* CONFIG_KASAN_STACK */
#define DEFINE_ASAN_REPORT_LOAD(size) \
void __asan_report_load##size##_noabort(void *addr) \
{ \
kasan_report(addr, size, false, _RET_IP_); \
} \
EXPORT_SYMBOL(__asan_report_load##size##_noabort)
#define DEFINE_ASAN_REPORT_STORE(size) \
void __asan_report_store##size##_noabort(void *addr) \
{ \
kasan_report(addr, size, true, _RET_IP_); \
} \
EXPORT_SYMBOL(__asan_report_store##size##_noabort)
DEFINE_ASAN_REPORT_LOAD(1);
DEFINE_ASAN_REPORT_LOAD(2);
DEFINE_ASAN_REPORT_LOAD(4);
DEFINE_ASAN_REPORT_LOAD(8);
DEFINE_ASAN_REPORT_LOAD(16);
DEFINE_ASAN_REPORT_STORE(1);
DEFINE_ASAN_REPORT_STORE(2);
DEFINE_ASAN_REPORT_STORE(4);
DEFINE_ASAN_REPORT_STORE(8);
DEFINE_ASAN_REPORT_STORE(16);
void __asan_report_load_n_noabort(void *addr, ssize_t size)
{
kasan_report(addr, size, false, _RET_IP_);
}
EXPORT_SYMBOL(__asan_report_load_n_noabort);
void __asan_report_store_n_noabort(void *addr, ssize_t size)
{
kasan_report(addr, size, true, _RET_IP_);
}
EXPORT_SYMBOL(__asan_report_store_n_noabort);
| linux-master | mm/kasan/report_generic.c |
// SPDX-License-Identifier: GPL-2.0
/*
* DAMON sysfs Interface
*
* Copyright (c) 2022 SeongJae Park <[email protected]>
*/
#include <linux/slab.h>
#include "sysfs-common.h"
/*
* scheme region directory
*/
struct damon_sysfs_scheme_region {
struct kobject kobj;
struct damon_addr_range ar;
unsigned int nr_accesses;
unsigned int age;
struct list_head list;
};
static struct damon_sysfs_scheme_region *damon_sysfs_scheme_region_alloc(
struct damon_region *region)
{
struct damon_sysfs_scheme_region *sysfs_region = kmalloc(
sizeof(*sysfs_region), GFP_KERNEL);
if (!sysfs_region)
return NULL;
sysfs_region->kobj = (struct kobject){};
sysfs_region->ar = region->ar;
sysfs_region->nr_accesses = region->nr_accesses;
sysfs_region->age = region->age;
INIT_LIST_HEAD(&sysfs_region->list);
return sysfs_region;
}
static ssize_t start_show(struct kobject *kobj, struct kobj_attribute *attr,
char *buf)
{
struct damon_sysfs_scheme_region *region = container_of(kobj,
struct damon_sysfs_scheme_region, kobj);
return sysfs_emit(buf, "%lu\n", region->ar.start);
}
static ssize_t end_show(struct kobject *kobj, struct kobj_attribute *attr,
char *buf)
{
struct damon_sysfs_scheme_region *region = container_of(kobj,
struct damon_sysfs_scheme_region, kobj);
return sysfs_emit(buf, "%lu\n", region->ar.end);
}
static ssize_t nr_accesses_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_scheme_region *region = container_of(kobj,
struct damon_sysfs_scheme_region, kobj);
return sysfs_emit(buf, "%u\n", region->nr_accesses);
}
static ssize_t age_show(struct kobject *kobj, struct kobj_attribute *attr,
char *buf)
{
struct damon_sysfs_scheme_region *region = container_of(kobj,
struct damon_sysfs_scheme_region, kobj);
return sysfs_emit(buf, "%u\n", region->age);
}
static void damon_sysfs_scheme_region_release(struct kobject *kobj)
{
struct damon_sysfs_scheme_region *region = container_of(kobj,
struct damon_sysfs_scheme_region, kobj);
list_del(®ion->list);
kfree(region);
}
static struct kobj_attribute damon_sysfs_scheme_region_start_attr =
__ATTR_RO_MODE(start, 0400);
static struct kobj_attribute damon_sysfs_scheme_region_end_attr =
__ATTR_RO_MODE(end, 0400);
static struct kobj_attribute damon_sysfs_scheme_region_nr_accesses_attr =
__ATTR_RO_MODE(nr_accesses, 0400);
static struct kobj_attribute damon_sysfs_scheme_region_age_attr =
__ATTR_RO_MODE(age, 0400);
static struct attribute *damon_sysfs_scheme_region_attrs[] = {
&damon_sysfs_scheme_region_start_attr.attr,
&damon_sysfs_scheme_region_end_attr.attr,
&damon_sysfs_scheme_region_nr_accesses_attr.attr,
&damon_sysfs_scheme_region_age_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(damon_sysfs_scheme_region);
static const struct kobj_type damon_sysfs_scheme_region_ktype = {
.release = damon_sysfs_scheme_region_release,
.sysfs_ops = &kobj_sysfs_ops,
.default_groups = damon_sysfs_scheme_region_groups,
};
/*
* scheme regions directory
*/
struct damon_sysfs_scheme_regions {
struct kobject kobj;
struct list_head regions_list;
int nr_regions;
unsigned long total_bytes;
};
static struct damon_sysfs_scheme_regions *
damon_sysfs_scheme_regions_alloc(void)
{
struct damon_sysfs_scheme_regions *regions = kmalloc(sizeof(*regions),
GFP_KERNEL);
regions->kobj = (struct kobject){};
INIT_LIST_HEAD(®ions->regions_list);
regions->nr_regions = 0;
regions->total_bytes = 0;
return regions;
}
static ssize_t total_bytes_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_scheme_regions *regions = container_of(kobj,
struct damon_sysfs_scheme_regions, kobj);
return sysfs_emit(buf, "%lu\n", regions->total_bytes);
}
static void damon_sysfs_scheme_regions_rm_dirs(
struct damon_sysfs_scheme_regions *regions)
{
struct damon_sysfs_scheme_region *r, *next;
list_for_each_entry_safe(r, next, ®ions->regions_list, list) {
/* release function deletes it from the list */
kobject_put(&r->kobj);
regions->nr_regions--;
}
}
static void damon_sysfs_scheme_regions_release(struct kobject *kobj)
{
kfree(container_of(kobj, struct damon_sysfs_scheme_regions, kobj));
}
static struct kobj_attribute damon_sysfs_scheme_regions_total_bytes_attr =
__ATTR_RO_MODE(total_bytes, 0400);
static struct attribute *damon_sysfs_scheme_regions_attrs[] = {
&damon_sysfs_scheme_regions_total_bytes_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(damon_sysfs_scheme_regions);
static const struct kobj_type damon_sysfs_scheme_regions_ktype = {
.release = damon_sysfs_scheme_regions_release,
.sysfs_ops = &kobj_sysfs_ops,
.default_groups = damon_sysfs_scheme_regions_groups,
};
/*
* schemes/stats directory
*/
struct damon_sysfs_stats {
struct kobject kobj;
unsigned long nr_tried;
unsigned long sz_tried;
unsigned long nr_applied;
unsigned long sz_applied;
unsigned long qt_exceeds;
};
static struct damon_sysfs_stats *damon_sysfs_stats_alloc(void)
{
return kzalloc(sizeof(struct damon_sysfs_stats), GFP_KERNEL);
}
static ssize_t nr_tried_show(struct kobject *kobj, struct kobj_attribute *attr,
char *buf)
{
struct damon_sysfs_stats *stats = container_of(kobj,
struct damon_sysfs_stats, kobj);
return sysfs_emit(buf, "%lu\n", stats->nr_tried);
}
static ssize_t sz_tried_show(struct kobject *kobj, struct kobj_attribute *attr,
char *buf)
{
struct damon_sysfs_stats *stats = container_of(kobj,
struct damon_sysfs_stats, kobj);
return sysfs_emit(buf, "%lu\n", stats->sz_tried);
}
static ssize_t nr_applied_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_stats *stats = container_of(kobj,
struct damon_sysfs_stats, kobj);
return sysfs_emit(buf, "%lu\n", stats->nr_applied);
}
static ssize_t sz_applied_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_stats *stats = container_of(kobj,
struct damon_sysfs_stats, kobj);
return sysfs_emit(buf, "%lu\n", stats->sz_applied);
}
static ssize_t qt_exceeds_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_stats *stats = container_of(kobj,
struct damon_sysfs_stats, kobj);
return sysfs_emit(buf, "%lu\n", stats->qt_exceeds);
}
static void damon_sysfs_stats_release(struct kobject *kobj)
{
kfree(container_of(kobj, struct damon_sysfs_stats, kobj));
}
static struct kobj_attribute damon_sysfs_stats_nr_tried_attr =
__ATTR_RO_MODE(nr_tried, 0400);
static struct kobj_attribute damon_sysfs_stats_sz_tried_attr =
__ATTR_RO_MODE(sz_tried, 0400);
static struct kobj_attribute damon_sysfs_stats_nr_applied_attr =
__ATTR_RO_MODE(nr_applied, 0400);
static struct kobj_attribute damon_sysfs_stats_sz_applied_attr =
__ATTR_RO_MODE(sz_applied, 0400);
static struct kobj_attribute damon_sysfs_stats_qt_exceeds_attr =
__ATTR_RO_MODE(qt_exceeds, 0400);
static struct attribute *damon_sysfs_stats_attrs[] = {
&damon_sysfs_stats_nr_tried_attr.attr,
&damon_sysfs_stats_sz_tried_attr.attr,
&damon_sysfs_stats_nr_applied_attr.attr,
&damon_sysfs_stats_sz_applied_attr.attr,
&damon_sysfs_stats_qt_exceeds_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(damon_sysfs_stats);
static const struct kobj_type damon_sysfs_stats_ktype = {
.release = damon_sysfs_stats_release,
.sysfs_ops = &kobj_sysfs_ops,
.default_groups = damon_sysfs_stats_groups,
};
/*
* filter directory
*/
struct damon_sysfs_scheme_filter {
struct kobject kobj;
enum damos_filter_type type;
bool matching;
char *memcg_path;
struct damon_addr_range addr_range;
int target_idx;
};
static struct damon_sysfs_scheme_filter *damon_sysfs_scheme_filter_alloc(void)
{
return kzalloc(sizeof(struct damon_sysfs_scheme_filter), GFP_KERNEL);
}
/* Should match with enum damos_filter_type */
static const char * const damon_sysfs_scheme_filter_type_strs[] = {
"anon",
"memcg",
"addr",
"target",
};
static ssize_t type_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_scheme_filter *filter = container_of(kobj,
struct damon_sysfs_scheme_filter, kobj);
return sysfs_emit(buf, "%s\n",
damon_sysfs_scheme_filter_type_strs[filter->type]);
}
static ssize_t type_store(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf, size_t count)
{
struct damon_sysfs_scheme_filter *filter = container_of(kobj,
struct damon_sysfs_scheme_filter, kobj);
enum damos_filter_type type;
ssize_t ret = -EINVAL;
for (type = 0; type < NR_DAMOS_FILTER_TYPES; type++) {
if (sysfs_streq(buf, damon_sysfs_scheme_filter_type_strs[
type])) {
filter->type = type;
ret = count;
break;
}
}
return ret;
}
static ssize_t matching_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_scheme_filter *filter = container_of(kobj,
struct damon_sysfs_scheme_filter, kobj);
return sysfs_emit(buf, "%c\n", filter->matching ? 'Y' : 'N');
}
static ssize_t matching_store(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf, size_t count)
{
struct damon_sysfs_scheme_filter *filter = container_of(kobj,
struct damon_sysfs_scheme_filter, kobj);
bool matching;
int err = kstrtobool(buf, &matching);
if (err)
return err;
filter->matching = matching;
return count;
}
static ssize_t memcg_path_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_scheme_filter *filter = container_of(kobj,
struct damon_sysfs_scheme_filter, kobj);
return sysfs_emit(buf, "%s\n",
filter->memcg_path ? filter->memcg_path : "");
}
static ssize_t memcg_path_store(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf, size_t count)
{
struct damon_sysfs_scheme_filter *filter = container_of(kobj,
struct damon_sysfs_scheme_filter, kobj);
char *path = kmalloc(sizeof(*path) * (count + 1), GFP_KERNEL);
if (!path)
return -ENOMEM;
strscpy(path, buf, count + 1);
filter->memcg_path = path;
return count;
}
static ssize_t addr_start_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_scheme_filter *filter = container_of(kobj,
struct damon_sysfs_scheme_filter, kobj);
return sysfs_emit(buf, "%lu\n", filter->addr_range.start);
}
static ssize_t addr_start_store(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf, size_t count)
{
struct damon_sysfs_scheme_filter *filter = container_of(kobj,
struct damon_sysfs_scheme_filter, kobj);
int err = kstrtoul(buf, 0, &filter->addr_range.start);
return err ? err : count;
}
static ssize_t addr_end_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_scheme_filter *filter = container_of(kobj,
struct damon_sysfs_scheme_filter, kobj);
return sysfs_emit(buf, "%lu\n", filter->addr_range.end);
}
static ssize_t addr_end_store(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf, size_t count)
{
struct damon_sysfs_scheme_filter *filter = container_of(kobj,
struct damon_sysfs_scheme_filter, kobj);
int err = kstrtoul(buf, 0, &filter->addr_range.end);
return err ? err : count;
}
static ssize_t damon_target_idx_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_scheme_filter *filter = container_of(kobj,
struct damon_sysfs_scheme_filter, kobj);
return sysfs_emit(buf, "%d\n", filter->target_idx);
}
static ssize_t damon_target_idx_store(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf, size_t count)
{
struct damon_sysfs_scheme_filter *filter = container_of(kobj,
struct damon_sysfs_scheme_filter, kobj);
int err = kstrtoint(buf, 0, &filter->target_idx);
return err ? err : count;
}
static void damon_sysfs_scheme_filter_release(struct kobject *kobj)
{
struct damon_sysfs_scheme_filter *filter = container_of(kobj,
struct damon_sysfs_scheme_filter, kobj);
kfree(filter->memcg_path);
kfree(filter);
}
static struct kobj_attribute damon_sysfs_scheme_filter_type_attr =
__ATTR_RW_MODE(type, 0600);
static struct kobj_attribute damon_sysfs_scheme_filter_matching_attr =
__ATTR_RW_MODE(matching, 0600);
static struct kobj_attribute damon_sysfs_scheme_filter_memcg_path_attr =
__ATTR_RW_MODE(memcg_path, 0600);
static struct kobj_attribute damon_sysfs_scheme_filter_addr_start_attr =
__ATTR_RW_MODE(addr_start, 0600);
static struct kobj_attribute damon_sysfs_scheme_filter_addr_end_attr =
__ATTR_RW_MODE(addr_end, 0600);
static struct kobj_attribute damon_sysfs_scheme_filter_damon_target_idx_attr =
__ATTR_RW_MODE(damon_target_idx, 0600);
static struct attribute *damon_sysfs_scheme_filter_attrs[] = {
&damon_sysfs_scheme_filter_type_attr.attr,
&damon_sysfs_scheme_filter_matching_attr.attr,
&damon_sysfs_scheme_filter_memcg_path_attr.attr,
&damon_sysfs_scheme_filter_addr_start_attr.attr,
&damon_sysfs_scheme_filter_addr_end_attr.attr,
&damon_sysfs_scheme_filter_damon_target_idx_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(damon_sysfs_scheme_filter);
static const struct kobj_type damon_sysfs_scheme_filter_ktype = {
.release = damon_sysfs_scheme_filter_release,
.sysfs_ops = &kobj_sysfs_ops,
.default_groups = damon_sysfs_scheme_filter_groups,
};
/*
* filters directory
*/
struct damon_sysfs_scheme_filters {
struct kobject kobj;
struct damon_sysfs_scheme_filter **filters_arr;
int nr;
};
static struct damon_sysfs_scheme_filters *
damon_sysfs_scheme_filters_alloc(void)
{
return kzalloc(sizeof(struct damon_sysfs_scheme_filters), GFP_KERNEL);
}
static void damon_sysfs_scheme_filters_rm_dirs(
struct damon_sysfs_scheme_filters *filters)
{
struct damon_sysfs_scheme_filter **filters_arr = filters->filters_arr;
int i;
for (i = 0; i < filters->nr; i++)
kobject_put(&filters_arr[i]->kobj);
filters->nr = 0;
kfree(filters_arr);
filters->filters_arr = NULL;
}
static int damon_sysfs_scheme_filters_add_dirs(
struct damon_sysfs_scheme_filters *filters, int nr_filters)
{
struct damon_sysfs_scheme_filter **filters_arr, *filter;
int err, i;
damon_sysfs_scheme_filters_rm_dirs(filters);
if (!nr_filters)
return 0;
filters_arr = kmalloc_array(nr_filters, sizeof(*filters_arr),
GFP_KERNEL | __GFP_NOWARN);
if (!filters_arr)
return -ENOMEM;
filters->filters_arr = filters_arr;
for (i = 0; i < nr_filters; i++) {
filter = damon_sysfs_scheme_filter_alloc();
if (!filter) {
damon_sysfs_scheme_filters_rm_dirs(filters);
return -ENOMEM;
}
err = kobject_init_and_add(&filter->kobj,
&damon_sysfs_scheme_filter_ktype,
&filters->kobj, "%d", i);
if (err) {
kobject_put(&filter->kobj);
damon_sysfs_scheme_filters_rm_dirs(filters);
return err;
}
filters_arr[i] = filter;
filters->nr++;
}
return 0;
}
static ssize_t nr_filters_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_scheme_filters *filters = container_of(kobj,
struct damon_sysfs_scheme_filters, kobj);
return sysfs_emit(buf, "%d\n", filters->nr);
}
static ssize_t nr_filters_store(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf, size_t count)
{
struct damon_sysfs_scheme_filters *filters;
int nr, err = kstrtoint(buf, 0, &nr);
if (err)
return err;
if (nr < 0)
return -EINVAL;
filters = container_of(kobj, struct damon_sysfs_scheme_filters, kobj);
if (!mutex_trylock(&damon_sysfs_lock))
return -EBUSY;
err = damon_sysfs_scheme_filters_add_dirs(filters, nr);
mutex_unlock(&damon_sysfs_lock);
if (err)
return err;
return count;
}
static void damon_sysfs_scheme_filters_release(struct kobject *kobj)
{
kfree(container_of(kobj, struct damon_sysfs_scheme_filters, kobj));
}
static struct kobj_attribute damon_sysfs_scheme_filters_nr_attr =
__ATTR_RW_MODE(nr_filters, 0600);
static struct attribute *damon_sysfs_scheme_filters_attrs[] = {
&damon_sysfs_scheme_filters_nr_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(damon_sysfs_scheme_filters);
static const struct kobj_type damon_sysfs_scheme_filters_ktype = {
.release = damon_sysfs_scheme_filters_release,
.sysfs_ops = &kobj_sysfs_ops,
.default_groups = damon_sysfs_scheme_filters_groups,
};
/*
* watermarks directory
*/
struct damon_sysfs_watermarks {
struct kobject kobj;
enum damos_wmark_metric metric;
unsigned long interval_us;
unsigned long high;
unsigned long mid;
unsigned long low;
};
static struct damon_sysfs_watermarks *damon_sysfs_watermarks_alloc(
enum damos_wmark_metric metric, unsigned long interval_us,
unsigned long high, unsigned long mid, unsigned long low)
{
struct damon_sysfs_watermarks *watermarks = kmalloc(
sizeof(*watermarks), GFP_KERNEL);
if (!watermarks)
return NULL;
watermarks->kobj = (struct kobject){};
watermarks->metric = metric;
watermarks->interval_us = interval_us;
watermarks->high = high;
watermarks->mid = mid;
watermarks->low = low;
return watermarks;
}
/* Should match with enum damos_wmark_metric */
static const char * const damon_sysfs_wmark_metric_strs[] = {
"none",
"free_mem_rate",
};
static ssize_t metric_show(struct kobject *kobj, struct kobj_attribute *attr,
char *buf)
{
struct damon_sysfs_watermarks *watermarks = container_of(kobj,
struct damon_sysfs_watermarks, kobj);
return sysfs_emit(buf, "%s\n",
damon_sysfs_wmark_metric_strs[watermarks->metric]);
}
static ssize_t metric_store(struct kobject *kobj, struct kobj_attribute *attr,
const char *buf, size_t count)
{
struct damon_sysfs_watermarks *watermarks = container_of(kobj,
struct damon_sysfs_watermarks, kobj);
enum damos_wmark_metric metric;
for (metric = 0; metric < NR_DAMOS_WMARK_METRICS; metric++) {
if (sysfs_streq(buf, damon_sysfs_wmark_metric_strs[metric])) {
watermarks->metric = metric;
return count;
}
}
return -EINVAL;
}
static ssize_t interval_us_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_watermarks *watermarks = container_of(kobj,
struct damon_sysfs_watermarks, kobj);
return sysfs_emit(buf, "%lu\n", watermarks->interval_us);
}
static ssize_t interval_us_store(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf, size_t count)
{
struct damon_sysfs_watermarks *watermarks = container_of(kobj,
struct damon_sysfs_watermarks, kobj);
int err = kstrtoul(buf, 0, &watermarks->interval_us);
return err ? err : count;
}
static ssize_t high_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_watermarks *watermarks = container_of(kobj,
struct damon_sysfs_watermarks, kobj);
return sysfs_emit(buf, "%lu\n", watermarks->high);
}
static ssize_t high_store(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf, size_t count)
{
struct damon_sysfs_watermarks *watermarks = container_of(kobj,
struct damon_sysfs_watermarks, kobj);
int err = kstrtoul(buf, 0, &watermarks->high);
return err ? err : count;
}
static ssize_t mid_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_watermarks *watermarks = container_of(kobj,
struct damon_sysfs_watermarks, kobj);
return sysfs_emit(buf, "%lu\n", watermarks->mid);
}
static ssize_t mid_store(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf, size_t count)
{
struct damon_sysfs_watermarks *watermarks = container_of(kobj,
struct damon_sysfs_watermarks, kobj);
int err = kstrtoul(buf, 0, &watermarks->mid);
return err ? err : count;
}
static ssize_t low_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_watermarks *watermarks = container_of(kobj,
struct damon_sysfs_watermarks, kobj);
return sysfs_emit(buf, "%lu\n", watermarks->low);
}
static ssize_t low_store(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf, size_t count)
{
struct damon_sysfs_watermarks *watermarks = container_of(kobj,
struct damon_sysfs_watermarks, kobj);
int err = kstrtoul(buf, 0, &watermarks->low);
return err ? err : count;
}
static void damon_sysfs_watermarks_release(struct kobject *kobj)
{
kfree(container_of(kobj, struct damon_sysfs_watermarks, kobj));
}
static struct kobj_attribute damon_sysfs_watermarks_metric_attr =
__ATTR_RW_MODE(metric, 0600);
static struct kobj_attribute damon_sysfs_watermarks_interval_us_attr =
__ATTR_RW_MODE(interval_us, 0600);
static struct kobj_attribute damon_sysfs_watermarks_high_attr =
__ATTR_RW_MODE(high, 0600);
static struct kobj_attribute damon_sysfs_watermarks_mid_attr =
__ATTR_RW_MODE(mid, 0600);
static struct kobj_attribute damon_sysfs_watermarks_low_attr =
__ATTR_RW_MODE(low, 0600);
static struct attribute *damon_sysfs_watermarks_attrs[] = {
&damon_sysfs_watermarks_metric_attr.attr,
&damon_sysfs_watermarks_interval_us_attr.attr,
&damon_sysfs_watermarks_high_attr.attr,
&damon_sysfs_watermarks_mid_attr.attr,
&damon_sysfs_watermarks_low_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(damon_sysfs_watermarks);
static const struct kobj_type damon_sysfs_watermarks_ktype = {
.release = damon_sysfs_watermarks_release,
.sysfs_ops = &kobj_sysfs_ops,
.default_groups = damon_sysfs_watermarks_groups,
};
/*
* scheme/weights directory
*/
struct damon_sysfs_weights {
struct kobject kobj;
unsigned int sz;
unsigned int nr_accesses;
unsigned int age;
};
static struct damon_sysfs_weights *damon_sysfs_weights_alloc(unsigned int sz,
unsigned int nr_accesses, unsigned int age)
{
struct damon_sysfs_weights *weights = kmalloc(sizeof(*weights),
GFP_KERNEL);
if (!weights)
return NULL;
weights->kobj = (struct kobject){};
weights->sz = sz;
weights->nr_accesses = nr_accesses;
weights->age = age;
return weights;
}
static ssize_t sz_permil_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_weights *weights = container_of(kobj,
struct damon_sysfs_weights, kobj);
return sysfs_emit(buf, "%u\n", weights->sz);
}
static ssize_t sz_permil_store(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf, size_t count)
{
struct damon_sysfs_weights *weights = container_of(kobj,
struct damon_sysfs_weights, kobj);
int err = kstrtouint(buf, 0, &weights->sz);
return err ? err : count;
}
static ssize_t nr_accesses_permil_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_weights *weights = container_of(kobj,
struct damon_sysfs_weights, kobj);
return sysfs_emit(buf, "%u\n", weights->nr_accesses);
}
static ssize_t nr_accesses_permil_store(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf, size_t count)
{
struct damon_sysfs_weights *weights = container_of(kobj,
struct damon_sysfs_weights, kobj);
int err = kstrtouint(buf, 0, &weights->nr_accesses);
return err ? err : count;
}
static ssize_t age_permil_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_weights *weights = container_of(kobj,
struct damon_sysfs_weights, kobj);
return sysfs_emit(buf, "%u\n", weights->age);
}
static ssize_t age_permil_store(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf, size_t count)
{
struct damon_sysfs_weights *weights = container_of(kobj,
struct damon_sysfs_weights, kobj);
int err = kstrtouint(buf, 0, &weights->age);
return err ? err : count;
}
static void damon_sysfs_weights_release(struct kobject *kobj)
{
kfree(container_of(kobj, struct damon_sysfs_weights, kobj));
}
static struct kobj_attribute damon_sysfs_weights_sz_attr =
__ATTR_RW_MODE(sz_permil, 0600);
static struct kobj_attribute damon_sysfs_weights_nr_accesses_attr =
__ATTR_RW_MODE(nr_accesses_permil, 0600);
static struct kobj_attribute damon_sysfs_weights_age_attr =
__ATTR_RW_MODE(age_permil, 0600);
static struct attribute *damon_sysfs_weights_attrs[] = {
&damon_sysfs_weights_sz_attr.attr,
&damon_sysfs_weights_nr_accesses_attr.attr,
&damon_sysfs_weights_age_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(damon_sysfs_weights);
static const struct kobj_type damon_sysfs_weights_ktype = {
.release = damon_sysfs_weights_release,
.sysfs_ops = &kobj_sysfs_ops,
.default_groups = damon_sysfs_weights_groups,
};
/*
* quotas directory
*/
struct damon_sysfs_quotas {
struct kobject kobj;
struct damon_sysfs_weights *weights;
unsigned long ms;
unsigned long sz;
unsigned long reset_interval_ms;
};
static struct damon_sysfs_quotas *damon_sysfs_quotas_alloc(void)
{
return kzalloc(sizeof(struct damon_sysfs_quotas), GFP_KERNEL);
}
static int damon_sysfs_quotas_add_dirs(struct damon_sysfs_quotas *quotas)
{
struct damon_sysfs_weights *weights;
int err;
weights = damon_sysfs_weights_alloc(0, 0, 0);
if (!weights)
return -ENOMEM;
err = kobject_init_and_add(&weights->kobj, &damon_sysfs_weights_ktype,
"as->kobj, "weights");
if (err)
kobject_put(&weights->kobj);
else
quotas->weights = weights;
return err;
}
static void damon_sysfs_quotas_rm_dirs(struct damon_sysfs_quotas *quotas)
{
kobject_put("as->weights->kobj);
}
static ssize_t ms_show(struct kobject *kobj, struct kobj_attribute *attr,
char *buf)
{
struct damon_sysfs_quotas *quotas = container_of(kobj,
struct damon_sysfs_quotas, kobj);
return sysfs_emit(buf, "%lu\n", quotas->ms);
}
static ssize_t ms_store(struct kobject *kobj, struct kobj_attribute *attr,
const char *buf, size_t count)
{
struct damon_sysfs_quotas *quotas = container_of(kobj,
struct damon_sysfs_quotas, kobj);
int err = kstrtoul(buf, 0, "as->ms);
if (err)
return -EINVAL;
return count;
}
static ssize_t bytes_show(struct kobject *kobj, struct kobj_attribute *attr,
char *buf)
{
struct damon_sysfs_quotas *quotas = container_of(kobj,
struct damon_sysfs_quotas, kobj);
return sysfs_emit(buf, "%lu\n", quotas->sz);
}
static ssize_t bytes_store(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf, size_t count)
{
struct damon_sysfs_quotas *quotas = container_of(kobj,
struct damon_sysfs_quotas, kobj);
int err = kstrtoul(buf, 0, "as->sz);
if (err)
return -EINVAL;
return count;
}
static ssize_t reset_interval_ms_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_quotas *quotas = container_of(kobj,
struct damon_sysfs_quotas, kobj);
return sysfs_emit(buf, "%lu\n", quotas->reset_interval_ms);
}
static ssize_t reset_interval_ms_store(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf, size_t count)
{
struct damon_sysfs_quotas *quotas = container_of(kobj,
struct damon_sysfs_quotas, kobj);
int err = kstrtoul(buf, 0, "as->reset_interval_ms);
if (err)
return -EINVAL;
return count;
}
static void damon_sysfs_quotas_release(struct kobject *kobj)
{
kfree(container_of(kobj, struct damon_sysfs_quotas, kobj));
}
static struct kobj_attribute damon_sysfs_quotas_ms_attr =
__ATTR_RW_MODE(ms, 0600);
static struct kobj_attribute damon_sysfs_quotas_sz_attr =
__ATTR_RW_MODE(bytes, 0600);
static struct kobj_attribute damon_sysfs_quotas_reset_interval_ms_attr =
__ATTR_RW_MODE(reset_interval_ms, 0600);
static struct attribute *damon_sysfs_quotas_attrs[] = {
&damon_sysfs_quotas_ms_attr.attr,
&damon_sysfs_quotas_sz_attr.attr,
&damon_sysfs_quotas_reset_interval_ms_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(damon_sysfs_quotas);
static const struct kobj_type damon_sysfs_quotas_ktype = {
.release = damon_sysfs_quotas_release,
.sysfs_ops = &kobj_sysfs_ops,
.default_groups = damon_sysfs_quotas_groups,
};
/*
* access_pattern directory
*/
struct damon_sysfs_access_pattern {
struct kobject kobj;
struct damon_sysfs_ul_range *sz;
struct damon_sysfs_ul_range *nr_accesses;
struct damon_sysfs_ul_range *age;
};
static
struct damon_sysfs_access_pattern *damon_sysfs_access_pattern_alloc(void)
{
struct damon_sysfs_access_pattern *access_pattern =
kmalloc(sizeof(*access_pattern), GFP_KERNEL);
if (!access_pattern)
return NULL;
access_pattern->kobj = (struct kobject){};
return access_pattern;
}
static int damon_sysfs_access_pattern_add_range_dir(
struct damon_sysfs_access_pattern *access_pattern,
struct damon_sysfs_ul_range **range_dir_ptr,
char *name)
{
struct damon_sysfs_ul_range *range = damon_sysfs_ul_range_alloc(0, 0);
int err;
if (!range)
return -ENOMEM;
err = kobject_init_and_add(&range->kobj, &damon_sysfs_ul_range_ktype,
&access_pattern->kobj, name);
if (err)
kobject_put(&range->kobj);
else
*range_dir_ptr = range;
return err;
}
static int damon_sysfs_access_pattern_add_dirs(
struct damon_sysfs_access_pattern *access_pattern)
{
int err;
err = damon_sysfs_access_pattern_add_range_dir(access_pattern,
&access_pattern->sz, "sz");
if (err)
goto put_sz_out;
err = damon_sysfs_access_pattern_add_range_dir(access_pattern,
&access_pattern->nr_accesses, "nr_accesses");
if (err)
goto put_nr_accesses_sz_out;
err = damon_sysfs_access_pattern_add_range_dir(access_pattern,
&access_pattern->age, "age");
if (err)
goto put_age_nr_accesses_sz_out;
return 0;
put_age_nr_accesses_sz_out:
kobject_put(&access_pattern->age->kobj);
access_pattern->age = NULL;
put_nr_accesses_sz_out:
kobject_put(&access_pattern->nr_accesses->kobj);
access_pattern->nr_accesses = NULL;
put_sz_out:
kobject_put(&access_pattern->sz->kobj);
access_pattern->sz = NULL;
return err;
}
static void damon_sysfs_access_pattern_rm_dirs(
struct damon_sysfs_access_pattern *access_pattern)
{
kobject_put(&access_pattern->sz->kobj);
kobject_put(&access_pattern->nr_accesses->kobj);
kobject_put(&access_pattern->age->kobj);
}
static void damon_sysfs_access_pattern_release(struct kobject *kobj)
{
kfree(container_of(kobj, struct damon_sysfs_access_pattern, kobj));
}
static struct attribute *damon_sysfs_access_pattern_attrs[] = {
NULL,
};
ATTRIBUTE_GROUPS(damon_sysfs_access_pattern);
static const struct kobj_type damon_sysfs_access_pattern_ktype = {
.release = damon_sysfs_access_pattern_release,
.sysfs_ops = &kobj_sysfs_ops,
.default_groups = damon_sysfs_access_pattern_groups,
};
/*
* scheme directory
*/
struct damon_sysfs_scheme {
struct kobject kobj;
enum damos_action action;
struct damon_sysfs_access_pattern *access_pattern;
struct damon_sysfs_quotas *quotas;
struct damon_sysfs_watermarks *watermarks;
struct damon_sysfs_scheme_filters *filters;
struct damon_sysfs_stats *stats;
struct damon_sysfs_scheme_regions *tried_regions;
};
/* This should match with enum damos_action */
static const char * const damon_sysfs_damos_action_strs[] = {
"willneed",
"cold",
"pageout",
"hugepage",
"nohugepage",
"lru_prio",
"lru_deprio",
"stat",
};
static struct damon_sysfs_scheme *damon_sysfs_scheme_alloc(
enum damos_action action)
{
struct damon_sysfs_scheme *scheme = kmalloc(sizeof(*scheme),
GFP_KERNEL);
if (!scheme)
return NULL;
scheme->kobj = (struct kobject){};
scheme->action = action;
return scheme;
}
static int damon_sysfs_scheme_set_access_pattern(
struct damon_sysfs_scheme *scheme)
{
struct damon_sysfs_access_pattern *access_pattern;
int err;
access_pattern = damon_sysfs_access_pattern_alloc();
if (!access_pattern)
return -ENOMEM;
err = kobject_init_and_add(&access_pattern->kobj,
&damon_sysfs_access_pattern_ktype, &scheme->kobj,
"access_pattern");
if (err)
goto out;
err = damon_sysfs_access_pattern_add_dirs(access_pattern);
if (err)
goto out;
scheme->access_pattern = access_pattern;
return 0;
out:
kobject_put(&access_pattern->kobj);
return err;
}
static int damon_sysfs_scheme_set_quotas(struct damon_sysfs_scheme *scheme)
{
struct damon_sysfs_quotas *quotas = damon_sysfs_quotas_alloc();
int err;
if (!quotas)
return -ENOMEM;
err = kobject_init_and_add("as->kobj, &damon_sysfs_quotas_ktype,
&scheme->kobj, "quotas");
if (err)
goto out;
err = damon_sysfs_quotas_add_dirs(quotas);
if (err)
goto out;
scheme->quotas = quotas;
return 0;
out:
kobject_put("as->kobj);
return err;
}
static int damon_sysfs_scheme_set_watermarks(struct damon_sysfs_scheme *scheme)
{
struct damon_sysfs_watermarks *watermarks =
damon_sysfs_watermarks_alloc(DAMOS_WMARK_NONE, 0, 0, 0, 0);
int err;
if (!watermarks)
return -ENOMEM;
err = kobject_init_and_add(&watermarks->kobj,
&damon_sysfs_watermarks_ktype, &scheme->kobj,
"watermarks");
if (err)
kobject_put(&watermarks->kobj);
else
scheme->watermarks = watermarks;
return err;
}
static int damon_sysfs_scheme_set_filters(struct damon_sysfs_scheme *scheme)
{
struct damon_sysfs_scheme_filters *filters =
damon_sysfs_scheme_filters_alloc();
int err;
if (!filters)
return -ENOMEM;
err = kobject_init_and_add(&filters->kobj,
&damon_sysfs_scheme_filters_ktype, &scheme->kobj,
"filters");
if (err)
kobject_put(&filters->kobj);
else
scheme->filters = filters;
return err;
}
static int damon_sysfs_scheme_set_stats(struct damon_sysfs_scheme *scheme)
{
struct damon_sysfs_stats *stats = damon_sysfs_stats_alloc();
int err;
if (!stats)
return -ENOMEM;
err = kobject_init_and_add(&stats->kobj, &damon_sysfs_stats_ktype,
&scheme->kobj, "stats");
if (err)
kobject_put(&stats->kobj);
else
scheme->stats = stats;
return err;
}
static int damon_sysfs_scheme_set_tried_regions(
struct damon_sysfs_scheme *scheme)
{
struct damon_sysfs_scheme_regions *tried_regions =
damon_sysfs_scheme_regions_alloc();
int err;
if (!tried_regions)
return -ENOMEM;
err = kobject_init_and_add(&tried_regions->kobj,
&damon_sysfs_scheme_regions_ktype, &scheme->kobj,
"tried_regions");
if (err)
kobject_put(&tried_regions->kobj);
else
scheme->tried_regions = tried_regions;
return err;
}
static int damon_sysfs_scheme_add_dirs(struct damon_sysfs_scheme *scheme)
{
int err;
err = damon_sysfs_scheme_set_access_pattern(scheme);
if (err)
return err;
err = damon_sysfs_scheme_set_quotas(scheme);
if (err)
goto put_access_pattern_out;
err = damon_sysfs_scheme_set_watermarks(scheme);
if (err)
goto put_quotas_access_pattern_out;
err = damon_sysfs_scheme_set_filters(scheme);
if (err)
goto put_watermarks_quotas_access_pattern_out;
err = damon_sysfs_scheme_set_stats(scheme);
if (err)
goto put_filters_watermarks_quotas_access_pattern_out;
err = damon_sysfs_scheme_set_tried_regions(scheme);
if (err)
goto put_tried_regions_out;
return 0;
put_tried_regions_out:
kobject_put(&scheme->tried_regions->kobj);
scheme->tried_regions = NULL;
put_filters_watermarks_quotas_access_pattern_out:
kobject_put(&scheme->filters->kobj);
scheme->filters = NULL;
put_watermarks_quotas_access_pattern_out:
kobject_put(&scheme->watermarks->kobj);
scheme->watermarks = NULL;
put_quotas_access_pattern_out:
kobject_put(&scheme->quotas->kobj);
scheme->quotas = NULL;
put_access_pattern_out:
kobject_put(&scheme->access_pattern->kobj);
scheme->access_pattern = NULL;
return err;
}
static void damon_sysfs_scheme_rm_dirs(struct damon_sysfs_scheme *scheme)
{
damon_sysfs_access_pattern_rm_dirs(scheme->access_pattern);
kobject_put(&scheme->access_pattern->kobj);
damon_sysfs_quotas_rm_dirs(scheme->quotas);
kobject_put(&scheme->quotas->kobj);
kobject_put(&scheme->watermarks->kobj);
damon_sysfs_scheme_filters_rm_dirs(scheme->filters);
kobject_put(&scheme->filters->kobj);
kobject_put(&scheme->stats->kobj);
damon_sysfs_scheme_regions_rm_dirs(scheme->tried_regions);
kobject_put(&scheme->tried_regions->kobj);
}
static ssize_t action_show(struct kobject *kobj, struct kobj_attribute *attr,
char *buf)
{
struct damon_sysfs_scheme *scheme = container_of(kobj,
struct damon_sysfs_scheme, kobj);
return sysfs_emit(buf, "%s\n",
damon_sysfs_damos_action_strs[scheme->action]);
}
static ssize_t action_store(struct kobject *kobj, struct kobj_attribute *attr,
const char *buf, size_t count)
{
struct damon_sysfs_scheme *scheme = container_of(kobj,
struct damon_sysfs_scheme, kobj);
enum damos_action action;
for (action = 0; action < NR_DAMOS_ACTIONS; action++) {
if (sysfs_streq(buf, damon_sysfs_damos_action_strs[action])) {
scheme->action = action;
return count;
}
}
return -EINVAL;
}
static void damon_sysfs_scheme_release(struct kobject *kobj)
{
kfree(container_of(kobj, struct damon_sysfs_scheme, kobj));
}
static struct kobj_attribute damon_sysfs_scheme_action_attr =
__ATTR_RW_MODE(action, 0600);
static struct attribute *damon_sysfs_scheme_attrs[] = {
&damon_sysfs_scheme_action_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(damon_sysfs_scheme);
static const struct kobj_type damon_sysfs_scheme_ktype = {
.release = damon_sysfs_scheme_release,
.sysfs_ops = &kobj_sysfs_ops,
.default_groups = damon_sysfs_scheme_groups,
};
/*
* schemes directory
*/
struct damon_sysfs_schemes *damon_sysfs_schemes_alloc(void)
{
return kzalloc(sizeof(struct damon_sysfs_schemes), GFP_KERNEL);
}
void damon_sysfs_schemes_rm_dirs(struct damon_sysfs_schemes *schemes)
{
struct damon_sysfs_scheme **schemes_arr = schemes->schemes_arr;
int i;
for (i = 0; i < schemes->nr; i++) {
damon_sysfs_scheme_rm_dirs(schemes_arr[i]);
kobject_put(&schemes_arr[i]->kobj);
}
schemes->nr = 0;
kfree(schemes_arr);
schemes->schemes_arr = NULL;
}
static int damon_sysfs_schemes_add_dirs(struct damon_sysfs_schemes *schemes,
int nr_schemes)
{
struct damon_sysfs_scheme **schemes_arr, *scheme;
int err, i;
damon_sysfs_schemes_rm_dirs(schemes);
if (!nr_schemes)
return 0;
schemes_arr = kmalloc_array(nr_schemes, sizeof(*schemes_arr),
GFP_KERNEL | __GFP_NOWARN);
if (!schemes_arr)
return -ENOMEM;
schemes->schemes_arr = schemes_arr;
for (i = 0; i < nr_schemes; i++) {
scheme = damon_sysfs_scheme_alloc(DAMOS_STAT);
if (!scheme) {
damon_sysfs_schemes_rm_dirs(schemes);
return -ENOMEM;
}
err = kobject_init_and_add(&scheme->kobj,
&damon_sysfs_scheme_ktype, &schemes->kobj,
"%d", i);
if (err)
goto out;
err = damon_sysfs_scheme_add_dirs(scheme);
if (err)
goto out;
schemes_arr[i] = scheme;
schemes->nr++;
}
return 0;
out:
damon_sysfs_schemes_rm_dirs(schemes);
kobject_put(&scheme->kobj);
return err;
}
static ssize_t nr_schemes_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_schemes *schemes = container_of(kobj,
struct damon_sysfs_schemes, kobj);
return sysfs_emit(buf, "%d\n", schemes->nr);
}
static ssize_t nr_schemes_store(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf, size_t count)
{
struct damon_sysfs_schemes *schemes;
int nr, err = kstrtoint(buf, 0, &nr);
if (err)
return err;
if (nr < 0)
return -EINVAL;
schemes = container_of(kobj, struct damon_sysfs_schemes, kobj);
if (!mutex_trylock(&damon_sysfs_lock))
return -EBUSY;
err = damon_sysfs_schemes_add_dirs(schemes, nr);
mutex_unlock(&damon_sysfs_lock);
if (err)
return err;
return count;
}
static void damon_sysfs_schemes_release(struct kobject *kobj)
{
kfree(container_of(kobj, struct damon_sysfs_schemes, kobj));
}
static struct kobj_attribute damon_sysfs_schemes_nr_attr =
__ATTR_RW_MODE(nr_schemes, 0600);
static struct attribute *damon_sysfs_schemes_attrs[] = {
&damon_sysfs_schemes_nr_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(damon_sysfs_schemes);
const struct kobj_type damon_sysfs_schemes_ktype = {
.release = damon_sysfs_schemes_release,
.sysfs_ops = &kobj_sysfs_ops,
.default_groups = damon_sysfs_schemes_groups,
};
static bool damon_sysfs_memcg_path_eq(struct mem_cgroup *memcg,
char *memcg_path_buf, char *path)
{
#ifdef CONFIG_MEMCG
cgroup_path(memcg->css.cgroup, memcg_path_buf, PATH_MAX);
if (sysfs_streq(memcg_path_buf, path))
return true;
#endif /* CONFIG_MEMCG */
return false;
}
static int damon_sysfs_memcg_path_to_id(char *memcg_path, unsigned short *id)
{
struct mem_cgroup *memcg;
char *path;
bool found = false;
if (!memcg_path)
return -EINVAL;
path = kmalloc(sizeof(*path) * PATH_MAX, GFP_KERNEL);
if (!path)
return -ENOMEM;
for (memcg = mem_cgroup_iter(NULL, NULL, NULL); memcg;
memcg = mem_cgroup_iter(NULL, memcg, NULL)) {
/* skip removed memcg */
if (!mem_cgroup_id(memcg))
continue;
if (damon_sysfs_memcg_path_eq(memcg, path, memcg_path)) {
*id = mem_cgroup_id(memcg);
found = true;
break;
}
}
kfree(path);
return found ? 0 : -EINVAL;
}
static int damon_sysfs_set_scheme_filters(struct damos *scheme,
struct damon_sysfs_scheme_filters *sysfs_filters)
{
int i;
struct damos_filter *filter, *next;
damos_for_each_filter_safe(filter, next, scheme)
damos_destroy_filter(filter);
for (i = 0; i < sysfs_filters->nr; i++) {
struct damon_sysfs_scheme_filter *sysfs_filter =
sysfs_filters->filters_arr[i];
struct damos_filter *filter =
damos_new_filter(sysfs_filter->type,
sysfs_filter->matching);
int err;
if (!filter)
return -ENOMEM;
if (filter->type == DAMOS_FILTER_TYPE_MEMCG) {
err = damon_sysfs_memcg_path_to_id(
sysfs_filter->memcg_path,
&filter->memcg_id);
if (err) {
damos_destroy_filter(filter);
return err;
}
} else if (filter->type == DAMOS_FILTER_TYPE_ADDR) {
if (sysfs_filter->addr_range.end <
sysfs_filter->addr_range.start) {
damos_destroy_filter(filter);
return -EINVAL;
}
filter->addr_range = sysfs_filter->addr_range;
} else if (filter->type == DAMOS_FILTER_TYPE_TARGET) {
filter->target_idx = sysfs_filter->target_idx;
}
damos_add_filter(scheme, filter);
}
return 0;
}
static struct damos *damon_sysfs_mk_scheme(
struct damon_sysfs_scheme *sysfs_scheme)
{
struct damon_sysfs_access_pattern *access_pattern =
sysfs_scheme->access_pattern;
struct damon_sysfs_quotas *sysfs_quotas = sysfs_scheme->quotas;
struct damon_sysfs_weights *sysfs_weights = sysfs_quotas->weights;
struct damon_sysfs_watermarks *sysfs_wmarks = sysfs_scheme->watermarks;
struct damon_sysfs_scheme_filters *sysfs_filters =
sysfs_scheme->filters;
struct damos *scheme;
int err;
struct damos_access_pattern pattern = {
.min_sz_region = access_pattern->sz->min,
.max_sz_region = access_pattern->sz->max,
.min_nr_accesses = access_pattern->nr_accesses->min,
.max_nr_accesses = access_pattern->nr_accesses->max,
.min_age_region = access_pattern->age->min,
.max_age_region = access_pattern->age->max,
};
struct damos_quota quota = {
.ms = sysfs_quotas->ms,
.sz = sysfs_quotas->sz,
.reset_interval = sysfs_quotas->reset_interval_ms,
.weight_sz = sysfs_weights->sz,
.weight_nr_accesses = sysfs_weights->nr_accesses,
.weight_age = sysfs_weights->age,
};
struct damos_watermarks wmarks = {
.metric = sysfs_wmarks->metric,
.interval = sysfs_wmarks->interval_us,
.high = sysfs_wmarks->high,
.mid = sysfs_wmarks->mid,
.low = sysfs_wmarks->low,
};
scheme = damon_new_scheme(&pattern, sysfs_scheme->action, "a,
&wmarks);
if (!scheme)
return NULL;
err = damon_sysfs_set_scheme_filters(scheme, sysfs_filters);
if (err) {
damon_destroy_scheme(scheme);
return NULL;
}
return scheme;
}
static void damon_sysfs_update_scheme(struct damos *scheme,
struct damon_sysfs_scheme *sysfs_scheme)
{
struct damon_sysfs_access_pattern *access_pattern =
sysfs_scheme->access_pattern;
struct damon_sysfs_quotas *sysfs_quotas = sysfs_scheme->quotas;
struct damon_sysfs_weights *sysfs_weights = sysfs_quotas->weights;
struct damon_sysfs_watermarks *sysfs_wmarks = sysfs_scheme->watermarks;
int err;
scheme->pattern.min_sz_region = access_pattern->sz->min;
scheme->pattern.max_sz_region = access_pattern->sz->max;
scheme->pattern.min_nr_accesses = access_pattern->nr_accesses->min;
scheme->pattern.max_nr_accesses = access_pattern->nr_accesses->max;
scheme->pattern.min_age_region = access_pattern->age->min;
scheme->pattern.max_age_region = access_pattern->age->max;
scheme->action = sysfs_scheme->action;
scheme->quota.ms = sysfs_quotas->ms;
scheme->quota.sz = sysfs_quotas->sz;
scheme->quota.reset_interval = sysfs_quotas->reset_interval_ms;
scheme->quota.weight_sz = sysfs_weights->sz;
scheme->quota.weight_nr_accesses = sysfs_weights->nr_accesses;
scheme->quota.weight_age = sysfs_weights->age;
scheme->wmarks.metric = sysfs_wmarks->metric;
scheme->wmarks.interval = sysfs_wmarks->interval_us;
scheme->wmarks.high = sysfs_wmarks->high;
scheme->wmarks.mid = sysfs_wmarks->mid;
scheme->wmarks.low = sysfs_wmarks->low;
err = damon_sysfs_set_scheme_filters(scheme, sysfs_scheme->filters);
if (err)
damon_destroy_scheme(scheme);
}
int damon_sysfs_set_schemes(struct damon_ctx *ctx,
struct damon_sysfs_schemes *sysfs_schemes)
{
struct damos *scheme, *next;
int i = 0;
damon_for_each_scheme_safe(scheme, next, ctx) {
if (i < sysfs_schemes->nr)
damon_sysfs_update_scheme(scheme,
sysfs_schemes->schemes_arr[i]);
else
damon_destroy_scheme(scheme);
i++;
}
for (; i < sysfs_schemes->nr; i++) {
struct damos *scheme, *next;
scheme = damon_sysfs_mk_scheme(sysfs_schemes->schemes_arr[i]);
if (!scheme) {
damon_for_each_scheme_safe(scheme, next, ctx)
damon_destroy_scheme(scheme);
return -ENOMEM;
}
damon_add_scheme(ctx, scheme);
}
return 0;
}
void damon_sysfs_schemes_update_stats(
struct damon_sysfs_schemes *sysfs_schemes,
struct damon_ctx *ctx)
{
struct damos *scheme;
int schemes_idx = 0;
damon_for_each_scheme(scheme, ctx) {
struct damon_sysfs_stats *sysfs_stats;
/* user could have removed the scheme sysfs dir */
if (schemes_idx >= sysfs_schemes->nr)
break;
sysfs_stats = sysfs_schemes->schemes_arr[schemes_idx++]->stats;
sysfs_stats->nr_tried = scheme->stat.nr_tried;
sysfs_stats->sz_tried = scheme->stat.sz_tried;
sysfs_stats->nr_applied = scheme->stat.nr_applied;
sysfs_stats->sz_applied = scheme->stat.sz_applied;
sysfs_stats->qt_exceeds = scheme->stat.qt_exceeds;
}
}
/*
* damon_sysfs_schemes that need to update its schemes regions dir. Protected
* by damon_sysfs_lock
*/
static struct damon_sysfs_schemes *damon_sysfs_schemes_for_damos_callback;
static int damon_sysfs_schemes_region_idx;
static bool damos_regions_upd_total_bytes_only;
/*
* DAMON callback that called before damos apply. While this callback is
* registered, damon_sysfs_lock should be held to ensure the regions
* directories exist.
*/
static int damon_sysfs_before_damos_apply(struct damon_ctx *ctx,
struct damon_target *t, struct damon_region *r,
struct damos *s)
{
struct damos *scheme;
struct damon_sysfs_scheme_regions *sysfs_regions;
struct damon_sysfs_scheme_region *region;
struct damon_sysfs_schemes *sysfs_schemes =
damon_sysfs_schemes_for_damos_callback;
int schemes_idx = 0;
damon_for_each_scheme(scheme, ctx) {
if (scheme == s)
break;
schemes_idx++;
}
/* user could have removed the scheme sysfs dir */
if (schemes_idx >= sysfs_schemes->nr)
return 0;
sysfs_regions = sysfs_schemes->schemes_arr[schemes_idx]->tried_regions;
sysfs_regions->total_bytes += r->ar.end - r->ar.start;
if (damos_regions_upd_total_bytes_only)
return 0;
region = damon_sysfs_scheme_region_alloc(r);
list_add_tail(®ion->list, &sysfs_regions->regions_list);
sysfs_regions->nr_regions++;
if (kobject_init_and_add(®ion->kobj,
&damon_sysfs_scheme_region_ktype,
&sysfs_regions->kobj, "%d",
damon_sysfs_schemes_region_idx++)) {
kobject_put(®ion->kobj);
}
return 0;
}
/* Called from damon_sysfs_cmd_request_callback under damon_sysfs_lock */
int damon_sysfs_schemes_clear_regions(
struct damon_sysfs_schemes *sysfs_schemes,
struct damon_ctx *ctx)
{
struct damos *scheme;
int schemes_idx = 0;
damon_for_each_scheme(scheme, ctx) {
struct damon_sysfs_scheme *sysfs_scheme;
/* user could have removed the scheme sysfs dir */
if (schemes_idx >= sysfs_schemes->nr)
break;
sysfs_scheme = sysfs_schemes->schemes_arr[schemes_idx++];
damon_sysfs_scheme_regions_rm_dirs(
sysfs_scheme->tried_regions);
sysfs_scheme->tried_regions->total_bytes = 0;
}
return 0;
}
/* Called from damon_sysfs_cmd_request_callback under damon_sysfs_lock */
int damon_sysfs_schemes_update_regions_start(
struct damon_sysfs_schemes *sysfs_schemes,
struct damon_ctx *ctx, bool total_bytes_only)
{
damon_sysfs_schemes_clear_regions(sysfs_schemes, ctx);
damon_sysfs_schemes_for_damos_callback = sysfs_schemes;
damos_regions_upd_total_bytes_only = total_bytes_only;
ctx->callback.before_damos_apply = damon_sysfs_before_damos_apply;
return 0;
}
/*
* Called from damon_sysfs_cmd_request_callback under damon_sysfs_lock. Caller
* should unlock damon_sysfs_lock which held before
* damon_sysfs_schemes_update_regions_start()
*/
int damon_sysfs_schemes_update_regions_stop(struct damon_ctx *ctx)
{
damon_sysfs_schemes_for_damos_callback = NULL;
ctx->callback.before_damos_apply = NULL;
damon_sysfs_schemes_region_idx = 0;
return 0;
}
| linux-master | mm/damon/sysfs-schemes.c |
// SPDX-License-Identifier: GPL-2.0
/*
* DAMON Debugfs Interface
*
* Author: SeongJae Park <[email protected]>
*/
#define pr_fmt(fmt) "damon-dbgfs: " fmt
#include <linux/damon.h>
#include <linux/debugfs.h>
#include <linux/file.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/page_idle.h>
#include <linux/slab.h>
static struct damon_ctx **dbgfs_ctxs;
static int dbgfs_nr_ctxs;
static struct dentry **dbgfs_dirs;
static DEFINE_MUTEX(damon_dbgfs_lock);
static void damon_dbgfs_warn_deprecation(void)
{
pr_warn_once("DAMON debugfs interface is deprecated, "
"so users should move to DAMON_SYSFS. If you cannot, "
"please report your usecase to [email protected] and "
"[email protected].\n");
}
/*
* Returns non-empty string on success, negative error code otherwise.
*/
static char *user_input_str(const char __user *buf, size_t count, loff_t *ppos)
{
char *kbuf;
ssize_t ret;
/* We do not accept continuous write */
if (*ppos)
return ERR_PTR(-EINVAL);
kbuf = kmalloc(count + 1, GFP_KERNEL | __GFP_NOWARN);
if (!kbuf)
return ERR_PTR(-ENOMEM);
ret = simple_write_to_buffer(kbuf, count + 1, ppos, buf, count);
if (ret != count) {
kfree(kbuf);
return ERR_PTR(-EIO);
}
kbuf[ret] = '\0';
return kbuf;
}
static ssize_t dbgfs_attrs_read(struct file *file,
char __user *buf, size_t count, loff_t *ppos)
{
struct damon_ctx *ctx = file->private_data;
char kbuf[128];
int ret;
mutex_lock(&ctx->kdamond_lock);
ret = scnprintf(kbuf, ARRAY_SIZE(kbuf), "%lu %lu %lu %lu %lu\n",
ctx->attrs.sample_interval, ctx->attrs.aggr_interval,
ctx->attrs.ops_update_interval,
ctx->attrs.min_nr_regions, ctx->attrs.max_nr_regions);
mutex_unlock(&ctx->kdamond_lock);
return simple_read_from_buffer(buf, count, ppos, kbuf, ret);
}
static ssize_t dbgfs_attrs_write(struct file *file,
const char __user *buf, size_t count, loff_t *ppos)
{
struct damon_ctx *ctx = file->private_data;
struct damon_attrs attrs;
char *kbuf;
ssize_t ret;
kbuf = user_input_str(buf, count, ppos);
if (IS_ERR(kbuf))
return PTR_ERR(kbuf);
if (sscanf(kbuf, "%lu %lu %lu %lu %lu",
&attrs.sample_interval, &attrs.aggr_interval,
&attrs.ops_update_interval,
&attrs.min_nr_regions,
&attrs.max_nr_regions) != 5) {
ret = -EINVAL;
goto out;
}
mutex_lock(&ctx->kdamond_lock);
if (ctx->kdamond) {
ret = -EBUSY;
goto unlock_out;
}
ret = damon_set_attrs(ctx, &attrs);
if (!ret)
ret = count;
unlock_out:
mutex_unlock(&ctx->kdamond_lock);
out:
kfree(kbuf);
return ret;
}
/*
* Return corresponding dbgfs' scheme action value (int) for the given
* damos_action if the given damos_action value is valid and supported by
* dbgfs, negative error code otherwise.
*/
static int damos_action_to_dbgfs_scheme_action(enum damos_action action)
{
switch (action) {
case DAMOS_WILLNEED:
return 0;
case DAMOS_COLD:
return 1;
case DAMOS_PAGEOUT:
return 2;
case DAMOS_HUGEPAGE:
return 3;
case DAMOS_NOHUGEPAGE:
return 4;
case DAMOS_STAT:
return 5;
default:
return -EINVAL;
}
}
static ssize_t sprint_schemes(struct damon_ctx *c, char *buf, ssize_t len)
{
struct damos *s;
int written = 0;
int rc;
damon_for_each_scheme(s, c) {
rc = scnprintf(&buf[written], len - written,
"%lu %lu %u %u %u %u %d %lu %lu %lu %u %u %u %d %lu %lu %lu %lu %lu %lu %lu %lu %lu\n",
s->pattern.min_sz_region,
s->pattern.max_sz_region,
s->pattern.min_nr_accesses,
s->pattern.max_nr_accesses,
s->pattern.min_age_region,
s->pattern.max_age_region,
damos_action_to_dbgfs_scheme_action(s->action),
s->quota.ms, s->quota.sz,
s->quota.reset_interval,
s->quota.weight_sz,
s->quota.weight_nr_accesses,
s->quota.weight_age,
s->wmarks.metric, s->wmarks.interval,
s->wmarks.high, s->wmarks.mid, s->wmarks.low,
s->stat.nr_tried, s->stat.sz_tried,
s->stat.nr_applied, s->stat.sz_applied,
s->stat.qt_exceeds);
if (!rc)
return -ENOMEM;
written += rc;
}
return written;
}
static ssize_t dbgfs_schemes_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
struct damon_ctx *ctx = file->private_data;
char *kbuf;
ssize_t len;
kbuf = kmalloc(count, GFP_KERNEL | __GFP_NOWARN);
if (!kbuf)
return -ENOMEM;
mutex_lock(&ctx->kdamond_lock);
len = sprint_schemes(ctx, kbuf, count);
mutex_unlock(&ctx->kdamond_lock);
if (len < 0)
goto out;
len = simple_read_from_buffer(buf, count, ppos, kbuf, len);
out:
kfree(kbuf);
return len;
}
static void free_schemes_arr(struct damos **schemes, ssize_t nr_schemes)
{
ssize_t i;
for (i = 0; i < nr_schemes; i++)
kfree(schemes[i]);
kfree(schemes);
}
/*
* Return corresponding damos_action for the given dbgfs input for a scheme
* action if the input is valid, negative error code otherwise.
*/
static enum damos_action dbgfs_scheme_action_to_damos_action(int dbgfs_action)
{
switch (dbgfs_action) {
case 0:
return DAMOS_WILLNEED;
case 1:
return DAMOS_COLD;
case 2:
return DAMOS_PAGEOUT;
case 3:
return DAMOS_HUGEPAGE;
case 4:
return DAMOS_NOHUGEPAGE;
case 5:
return DAMOS_STAT;
default:
return -EINVAL;
}
}
/*
* Converts a string into an array of struct damos pointers
*
* Returns an array of struct damos pointers that converted if the conversion
* success, or NULL otherwise.
*/
static struct damos **str_to_schemes(const char *str, ssize_t len,
ssize_t *nr_schemes)
{
struct damos *scheme, **schemes;
const int max_nr_schemes = 256;
int pos = 0, parsed, ret;
unsigned int action_input;
enum damos_action action;
schemes = kmalloc_array(max_nr_schemes, sizeof(scheme),
GFP_KERNEL);
if (!schemes)
return NULL;
*nr_schemes = 0;
while (pos < len && *nr_schemes < max_nr_schemes) {
struct damos_access_pattern pattern = {};
struct damos_quota quota = {};
struct damos_watermarks wmarks;
ret = sscanf(&str[pos],
"%lu %lu %u %u %u %u %u %lu %lu %lu %u %u %u %u %lu %lu %lu %lu%n",
&pattern.min_sz_region, &pattern.max_sz_region,
&pattern.min_nr_accesses,
&pattern.max_nr_accesses,
&pattern.min_age_region,
&pattern.max_age_region,
&action_input, "a.ms,
"a.sz, "a.reset_interval,
"a.weight_sz, "a.weight_nr_accesses,
"a.weight_age, &wmarks.metric,
&wmarks.interval, &wmarks.high, &wmarks.mid,
&wmarks.low, &parsed);
if (ret != 18)
break;
action = dbgfs_scheme_action_to_damos_action(action_input);
if ((int)action < 0)
goto fail;
if (pattern.min_sz_region > pattern.max_sz_region ||
pattern.min_nr_accesses > pattern.max_nr_accesses ||
pattern.min_age_region > pattern.max_age_region)
goto fail;
if (wmarks.high < wmarks.mid || wmarks.high < wmarks.low ||
wmarks.mid < wmarks.low)
goto fail;
pos += parsed;
scheme = damon_new_scheme(&pattern, action, "a, &wmarks);
if (!scheme)
goto fail;
schemes[*nr_schemes] = scheme;
*nr_schemes += 1;
}
return schemes;
fail:
free_schemes_arr(schemes, *nr_schemes);
return NULL;
}
static ssize_t dbgfs_schemes_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
struct damon_ctx *ctx = file->private_data;
char *kbuf;
struct damos **schemes;
ssize_t nr_schemes = 0, ret;
kbuf = user_input_str(buf, count, ppos);
if (IS_ERR(kbuf))
return PTR_ERR(kbuf);
schemes = str_to_schemes(kbuf, count, &nr_schemes);
if (!schemes) {
ret = -EINVAL;
goto out;
}
mutex_lock(&ctx->kdamond_lock);
if (ctx->kdamond) {
ret = -EBUSY;
goto unlock_out;
}
damon_set_schemes(ctx, schemes, nr_schemes);
ret = count;
nr_schemes = 0;
unlock_out:
mutex_unlock(&ctx->kdamond_lock);
free_schemes_arr(schemes, nr_schemes);
out:
kfree(kbuf);
return ret;
}
static ssize_t sprint_target_ids(struct damon_ctx *ctx, char *buf, ssize_t len)
{
struct damon_target *t;
int id;
int written = 0;
int rc;
damon_for_each_target(t, ctx) {
if (damon_target_has_pid(ctx))
/* Show pid numbers to debugfs users */
id = pid_vnr(t->pid);
else
/* Show 42 for physical address space, just for fun */
id = 42;
rc = scnprintf(&buf[written], len - written, "%d ", id);
if (!rc)
return -ENOMEM;
written += rc;
}
if (written)
written -= 1;
written += scnprintf(&buf[written], len - written, "\n");
return written;
}
static ssize_t dbgfs_target_ids_read(struct file *file,
char __user *buf, size_t count, loff_t *ppos)
{
struct damon_ctx *ctx = file->private_data;
ssize_t len;
char ids_buf[320];
mutex_lock(&ctx->kdamond_lock);
len = sprint_target_ids(ctx, ids_buf, 320);
mutex_unlock(&ctx->kdamond_lock);
if (len < 0)
return len;
return simple_read_from_buffer(buf, count, ppos, ids_buf, len);
}
/*
* Converts a string into an integers array
*
* Returns an array of integers array if the conversion success, or NULL
* otherwise.
*/
static int *str_to_ints(const char *str, ssize_t len, ssize_t *nr_ints)
{
int *array;
const int max_nr_ints = 32;
int nr;
int pos = 0, parsed, ret;
*nr_ints = 0;
array = kmalloc_array(max_nr_ints, sizeof(*array), GFP_KERNEL);
if (!array)
return NULL;
while (*nr_ints < max_nr_ints && pos < len) {
ret = sscanf(&str[pos], "%d%n", &nr, &parsed);
pos += parsed;
if (ret != 1)
break;
array[*nr_ints] = nr;
*nr_ints += 1;
}
return array;
}
static void dbgfs_put_pids(struct pid **pids, int nr_pids)
{
int i;
for (i = 0; i < nr_pids; i++)
put_pid(pids[i]);
}
/*
* Converts a string into an struct pid pointers array
*
* Returns an array of struct pid pointers if the conversion success, or NULL
* otherwise.
*/
static struct pid **str_to_pids(const char *str, ssize_t len, ssize_t *nr_pids)
{
int *ints;
ssize_t nr_ints;
struct pid **pids;
*nr_pids = 0;
ints = str_to_ints(str, len, &nr_ints);
if (!ints)
return NULL;
pids = kmalloc_array(nr_ints, sizeof(*pids), GFP_KERNEL);
if (!pids)
goto out;
for (; *nr_pids < nr_ints; (*nr_pids)++) {
pids[*nr_pids] = find_get_pid(ints[*nr_pids]);
if (!pids[*nr_pids]) {
dbgfs_put_pids(pids, *nr_pids);
kfree(ints);
kfree(pids);
return NULL;
}
}
out:
kfree(ints);
return pids;
}
/*
* dbgfs_set_targets() - Set monitoring targets.
* @ctx: monitoring context
* @nr_targets: number of targets
* @pids: array of target pids (size is same to @nr_targets)
*
* This function should not be called while the kdamond is running. @pids is
* ignored if the context is not configured to have pid in each target. On
* failure, reference counts of all pids in @pids are decremented.
*
* Return: 0 on success, negative error code otherwise.
*/
static int dbgfs_set_targets(struct damon_ctx *ctx, ssize_t nr_targets,
struct pid **pids)
{
ssize_t i;
struct damon_target *t, *next;
damon_for_each_target_safe(t, next, ctx) {
if (damon_target_has_pid(ctx))
put_pid(t->pid);
damon_destroy_target(t);
}
for (i = 0; i < nr_targets; i++) {
t = damon_new_target();
if (!t) {
damon_for_each_target_safe(t, next, ctx)
damon_destroy_target(t);
if (damon_target_has_pid(ctx))
dbgfs_put_pids(pids, nr_targets);
return -ENOMEM;
}
if (damon_target_has_pid(ctx))
t->pid = pids[i];
damon_add_target(ctx, t);
}
return 0;
}
static ssize_t dbgfs_target_ids_write(struct file *file,
const char __user *buf, size_t count, loff_t *ppos)
{
struct damon_ctx *ctx = file->private_data;
bool id_is_pid = true;
char *kbuf;
struct pid **target_pids = NULL;
ssize_t nr_targets;
ssize_t ret;
kbuf = user_input_str(buf, count, ppos);
if (IS_ERR(kbuf))
return PTR_ERR(kbuf);
if (!strncmp(kbuf, "paddr\n", count)) {
id_is_pid = false;
nr_targets = 1;
}
if (id_is_pid) {
target_pids = str_to_pids(kbuf, count, &nr_targets);
if (!target_pids) {
ret = -ENOMEM;
goto out;
}
}
mutex_lock(&ctx->kdamond_lock);
if (ctx->kdamond) {
if (id_is_pid)
dbgfs_put_pids(target_pids, nr_targets);
ret = -EBUSY;
goto unlock_out;
}
/* remove previously set targets */
dbgfs_set_targets(ctx, 0, NULL);
if (!nr_targets) {
ret = count;
goto unlock_out;
}
/* Configure the context for the address space type */
if (id_is_pid)
ret = damon_select_ops(ctx, DAMON_OPS_VADDR);
else
ret = damon_select_ops(ctx, DAMON_OPS_PADDR);
if (ret)
goto unlock_out;
ret = dbgfs_set_targets(ctx, nr_targets, target_pids);
if (!ret)
ret = count;
unlock_out:
mutex_unlock(&ctx->kdamond_lock);
kfree(target_pids);
out:
kfree(kbuf);
return ret;
}
static ssize_t sprint_init_regions(struct damon_ctx *c, char *buf, ssize_t len)
{
struct damon_target *t;
struct damon_region *r;
int target_idx = 0;
int written = 0;
int rc;
damon_for_each_target(t, c) {
damon_for_each_region(r, t) {
rc = scnprintf(&buf[written], len - written,
"%d %lu %lu\n",
target_idx, r->ar.start, r->ar.end);
if (!rc)
return -ENOMEM;
written += rc;
}
target_idx++;
}
return written;
}
static ssize_t dbgfs_init_regions_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
struct damon_ctx *ctx = file->private_data;
char *kbuf;
ssize_t len;
kbuf = kmalloc(count, GFP_KERNEL | __GFP_NOWARN);
if (!kbuf)
return -ENOMEM;
mutex_lock(&ctx->kdamond_lock);
if (ctx->kdamond) {
mutex_unlock(&ctx->kdamond_lock);
len = -EBUSY;
goto out;
}
len = sprint_init_regions(ctx, kbuf, count);
mutex_unlock(&ctx->kdamond_lock);
if (len < 0)
goto out;
len = simple_read_from_buffer(buf, count, ppos, kbuf, len);
out:
kfree(kbuf);
return len;
}
static int add_init_region(struct damon_ctx *c, int target_idx,
struct damon_addr_range *ar)
{
struct damon_target *t;
struct damon_region *r, *prev;
unsigned long idx = 0;
int rc = -EINVAL;
if (ar->start >= ar->end)
return -EINVAL;
damon_for_each_target(t, c) {
if (idx++ == target_idx) {
r = damon_new_region(ar->start, ar->end);
if (!r)
return -ENOMEM;
damon_add_region(r, t);
if (damon_nr_regions(t) > 1) {
prev = damon_prev_region(r);
if (prev->ar.end > r->ar.start) {
damon_destroy_region(r, t);
return -EINVAL;
}
}
rc = 0;
}
}
return rc;
}
static int set_init_regions(struct damon_ctx *c, const char *str, ssize_t len)
{
struct damon_target *t;
struct damon_region *r, *next;
int pos = 0, parsed, ret;
int target_idx;
struct damon_addr_range ar;
int err;
damon_for_each_target(t, c) {
damon_for_each_region_safe(r, next, t)
damon_destroy_region(r, t);
}
while (pos < len) {
ret = sscanf(&str[pos], "%d %lu %lu%n",
&target_idx, &ar.start, &ar.end, &parsed);
if (ret != 3)
break;
err = add_init_region(c, target_idx, &ar);
if (err)
goto fail;
pos += parsed;
}
return 0;
fail:
damon_for_each_target(t, c) {
damon_for_each_region_safe(r, next, t)
damon_destroy_region(r, t);
}
return err;
}
static ssize_t dbgfs_init_regions_write(struct file *file,
const char __user *buf, size_t count,
loff_t *ppos)
{
struct damon_ctx *ctx = file->private_data;
char *kbuf;
ssize_t ret = count;
int err;
kbuf = user_input_str(buf, count, ppos);
if (IS_ERR(kbuf))
return PTR_ERR(kbuf);
mutex_lock(&ctx->kdamond_lock);
if (ctx->kdamond) {
ret = -EBUSY;
goto unlock_out;
}
err = set_init_regions(ctx, kbuf, ret);
if (err)
ret = err;
unlock_out:
mutex_unlock(&ctx->kdamond_lock);
kfree(kbuf);
return ret;
}
static ssize_t dbgfs_kdamond_pid_read(struct file *file,
char __user *buf, size_t count, loff_t *ppos)
{
struct damon_ctx *ctx = file->private_data;
char *kbuf;
ssize_t len;
kbuf = kmalloc(count, GFP_KERNEL | __GFP_NOWARN);
if (!kbuf)
return -ENOMEM;
mutex_lock(&ctx->kdamond_lock);
if (ctx->kdamond)
len = scnprintf(kbuf, count, "%d\n", ctx->kdamond->pid);
else
len = scnprintf(kbuf, count, "none\n");
mutex_unlock(&ctx->kdamond_lock);
if (!len)
goto out;
len = simple_read_from_buffer(buf, count, ppos, kbuf, len);
out:
kfree(kbuf);
return len;
}
static int damon_dbgfs_open(struct inode *inode, struct file *file)
{
damon_dbgfs_warn_deprecation();
file->private_data = inode->i_private;
return nonseekable_open(inode, file);
}
static const struct file_operations attrs_fops = {
.open = damon_dbgfs_open,
.read = dbgfs_attrs_read,
.write = dbgfs_attrs_write,
};
static const struct file_operations schemes_fops = {
.open = damon_dbgfs_open,
.read = dbgfs_schemes_read,
.write = dbgfs_schemes_write,
};
static const struct file_operations target_ids_fops = {
.open = damon_dbgfs_open,
.read = dbgfs_target_ids_read,
.write = dbgfs_target_ids_write,
};
static const struct file_operations init_regions_fops = {
.open = damon_dbgfs_open,
.read = dbgfs_init_regions_read,
.write = dbgfs_init_regions_write,
};
static const struct file_operations kdamond_pid_fops = {
.open = damon_dbgfs_open,
.read = dbgfs_kdamond_pid_read,
};
static void dbgfs_fill_ctx_dir(struct dentry *dir, struct damon_ctx *ctx)
{
const char * const file_names[] = {"attrs", "schemes", "target_ids",
"init_regions", "kdamond_pid"};
const struct file_operations *fops[] = {&attrs_fops, &schemes_fops,
&target_ids_fops, &init_regions_fops, &kdamond_pid_fops};
int i;
for (i = 0; i < ARRAY_SIZE(file_names); i++)
debugfs_create_file(file_names[i], 0600, dir, ctx, fops[i]);
}
static void dbgfs_before_terminate(struct damon_ctx *ctx)
{
struct damon_target *t, *next;
if (!damon_target_has_pid(ctx))
return;
mutex_lock(&ctx->kdamond_lock);
damon_for_each_target_safe(t, next, ctx) {
put_pid(t->pid);
damon_destroy_target(t);
}
mutex_unlock(&ctx->kdamond_lock);
}
static struct damon_ctx *dbgfs_new_ctx(void)
{
struct damon_ctx *ctx;
ctx = damon_new_ctx();
if (!ctx)
return NULL;
if (damon_select_ops(ctx, DAMON_OPS_VADDR) &&
damon_select_ops(ctx, DAMON_OPS_PADDR)) {
damon_destroy_ctx(ctx);
return NULL;
}
ctx->callback.before_terminate = dbgfs_before_terminate;
return ctx;
}
static void dbgfs_destroy_ctx(struct damon_ctx *ctx)
{
damon_destroy_ctx(ctx);
}
/*
* Make a context of @name and create a debugfs directory for it.
*
* This function should be called while holding damon_dbgfs_lock.
*
* Returns 0 on success, negative error code otherwise.
*/
static int dbgfs_mk_context(char *name)
{
struct dentry *root, **new_dirs, *new_dir;
struct damon_ctx **new_ctxs, *new_ctx;
if (damon_nr_running_ctxs())
return -EBUSY;
new_ctxs = krealloc(dbgfs_ctxs, sizeof(*dbgfs_ctxs) *
(dbgfs_nr_ctxs + 1), GFP_KERNEL);
if (!new_ctxs)
return -ENOMEM;
dbgfs_ctxs = new_ctxs;
new_dirs = krealloc(dbgfs_dirs, sizeof(*dbgfs_dirs) *
(dbgfs_nr_ctxs + 1), GFP_KERNEL);
if (!new_dirs)
return -ENOMEM;
dbgfs_dirs = new_dirs;
root = dbgfs_dirs[0];
if (!root)
return -ENOENT;
new_dir = debugfs_create_dir(name, root);
/* Below check is required for a potential duplicated name case */
if (IS_ERR(new_dir))
return PTR_ERR(new_dir);
dbgfs_dirs[dbgfs_nr_ctxs] = new_dir;
new_ctx = dbgfs_new_ctx();
if (!new_ctx) {
debugfs_remove(new_dir);
dbgfs_dirs[dbgfs_nr_ctxs] = NULL;
return -ENOMEM;
}
dbgfs_ctxs[dbgfs_nr_ctxs] = new_ctx;
dbgfs_fill_ctx_dir(dbgfs_dirs[dbgfs_nr_ctxs],
dbgfs_ctxs[dbgfs_nr_ctxs]);
dbgfs_nr_ctxs++;
return 0;
}
static ssize_t dbgfs_mk_context_write(struct file *file,
const char __user *buf, size_t count, loff_t *ppos)
{
char *kbuf;
char *ctx_name;
ssize_t ret;
kbuf = user_input_str(buf, count, ppos);
if (IS_ERR(kbuf))
return PTR_ERR(kbuf);
ctx_name = kmalloc(count + 1, GFP_KERNEL);
if (!ctx_name) {
kfree(kbuf);
return -ENOMEM;
}
/* Trim white space */
if (sscanf(kbuf, "%s", ctx_name) != 1) {
ret = -EINVAL;
goto out;
}
mutex_lock(&damon_dbgfs_lock);
ret = dbgfs_mk_context(ctx_name);
if (!ret)
ret = count;
mutex_unlock(&damon_dbgfs_lock);
out:
kfree(kbuf);
kfree(ctx_name);
return ret;
}
/*
* Remove a context of @name and its debugfs directory.
*
* This function should be called while holding damon_dbgfs_lock.
*
* Return 0 on success, negative error code otherwise.
*/
static int dbgfs_rm_context(char *name)
{
struct dentry *root, *dir, **new_dirs;
struct inode *inode;
struct damon_ctx **new_ctxs;
int i, j;
int ret = 0;
if (damon_nr_running_ctxs())
return -EBUSY;
root = dbgfs_dirs[0];
if (!root)
return -ENOENT;
dir = debugfs_lookup(name, root);
if (!dir)
return -ENOENT;
inode = d_inode(dir);
if (!S_ISDIR(inode->i_mode)) {
ret = -EINVAL;
goto out_dput;
}
new_dirs = kmalloc_array(dbgfs_nr_ctxs - 1, sizeof(*dbgfs_dirs),
GFP_KERNEL);
if (!new_dirs) {
ret = -ENOMEM;
goto out_dput;
}
new_ctxs = kmalloc_array(dbgfs_nr_ctxs - 1, sizeof(*dbgfs_ctxs),
GFP_KERNEL);
if (!new_ctxs) {
ret = -ENOMEM;
goto out_new_dirs;
}
for (i = 0, j = 0; i < dbgfs_nr_ctxs; i++) {
if (dbgfs_dirs[i] == dir) {
debugfs_remove(dbgfs_dirs[i]);
dbgfs_destroy_ctx(dbgfs_ctxs[i]);
continue;
}
new_dirs[j] = dbgfs_dirs[i];
new_ctxs[j++] = dbgfs_ctxs[i];
}
kfree(dbgfs_dirs);
kfree(dbgfs_ctxs);
dbgfs_dirs = new_dirs;
dbgfs_ctxs = new_ctxs;
dbgfs_nr_ctxs--;
goto out_dput;
out_new_dirs:
kfree(new_dirs);
out_dput:
dput(dir);
return ret;
}
static ssize_t dbgfs_rm_context_write(struct file *file,
const char __user *buf, size_t count, loff_t *ppos)
{
char *kbuf;
ssize_t ret;
char *ctx_name;
kbuf = user_input_str(buf, count, ppos);
if (IS_ERR(kbuf))
return PTR_ERR(kbuf);
ctx_name = kmalloc(count + 1, GFP_KERNEL);
if (!ctx_name) {
kfree(kbuf);
return -ENOMEM;
}
/* Trim white space */
if (sscanf(kbuf, "%s", ctx_name) != 1) {
ret = -EINVAL;
goto out;
}
mutex_lock(&damon_dbgfs_lock);
ret = dbgfs_rm_context(ctx_name);
if (!ret)
ret = count;
mutex_unlock(&damon_dbgfs_lock);
out:
kfree(kbuf);
kfree(ctx_name);
return ret;
}
static ssize_t dbgfs_monitor_on_read(struct file *file,
char __user *buf, size_t count, loff_t *ppos)
{
char monitor_on_buf[5];
bool monitor_on = damon_nr_running_ctxs() != 0;
int len;
len = scnprintf(monitor_on_buf, 5, monitor_on ? "on\n" : "off\n");
return simple_read_from_buffer(buf, count, ppos, monitor_on_buf, len);
}
static ssize_t dbgfs_monitor_on_write(struct file *file,
const char __user *buf, size_t count, loff_t *ppos)
{
ssize_t ret;
char *kbuf;
kbuf = user_input_str(buf, count, ppos);
if (IS_ERR(kbuf))
return PTR_ERR(kbuf);
/* Remove white space */
if (sscanf(kbuf, "%s", kbuf) != 1) {
kfree(kbuf);
return -EINVAL;
}
mutex_lock(&damon_dbgfs_lock);
if (!strncmp(kbuf, "on", count)) {
int i;
for (i = 0; i < dbgfs_nr_ctxs; i++) {
if (damon_targets_empty(dbgfs_ctxs[i])) {
kfree(kbuf);
mutex_unlock(&damon_dbgfs_lock);
return -EINVAL;
}
}
ret = damon_start(dbgfs_ctxs, dbgfs_nr_ctxs, true);
} else if (!strncmp(kbuf, "off", count)) {
ret = damon_stop(dbgfs_ctxs, dbgfs_nr_ctxs);
} else {
ret = -EINVAL;
}
mutex_unlock(&damon_dbgfs_lock);
if (!ret)
ret = count;
kfree(kbuf);
return ret;
}
static int damon_dbgfs_static_file_open(struct inode *inode, struct file *file)
{
damon_dbgfs_warn_deprecation();
return nonseekable_open(inode, file);
}
static const struct file_operations mk_contexts_fops = {
.open = damon_dbgfs_static_file_open,
.write = dbgfs_mk_context_write,
};
static const struct file_operations rm_contexts_fops = {
.open = damon_dbgfs_static_file_open,
.write = dbgfs_rm_context_write,
};
static const struct file_operations monitor_on_fops = {
.open = damon_dbgfs_static_file_open,
.read = dbgfs_monitor_on_read,
.write = dbgfs_monitor_on_write,
};
static int __init __damon_dbgfs_init(void)
{
struct dentry *dbgfs_root;
const char * const file_names[] = {"mk_contexts", "rm_contexts",
"monitor_on"};
const struct file_operations *fops[] = {&mk_contexts_fops,
&rm_contexts_fops, &monitor_on_fops};
int i;
dbgfs_root = debugfs_create_dir("damon", NULL);
for (i = 0; i < ARRAY_SIZE(file_names); i++)
debugfs_create_file(file_names[i], 0600, dbgfs_root, NULL,
fops[i]);
dbgfs_fill_ctx_dir(dbgfs_root, dbgfs_ctxs[0]);
dbgfs_dirs = kmalloc(sizeof(dbgfs_root), GFP_KERNEL);
if (!dbgfs_dirs) {
debugfs_remove(dbgfs_root);
return -ENOMEM;
}
dbgfs_dirs[0] = dbgfs_root;
return 0;
}
/*
* Functions for the initialization
*/
static int __init damon_dbgfs_init(void)
{
int rc = -ENOMEM;
mutex_lock(&damon_dbgfs_lock);
dbgfs_ctxs = kmalloc(sizeof(*dbgfs_ctxs), GFP_KERNEL);
if (!dbgfs_ctxs)
goto out;
dbgfs_ctxs[0] = dbgfs_new_ctx();
if (!dbgfs_ctxs[0]) {
kfree(dbgfs_ctxs);
goto out;
}
dbgfs_nr_ctxs = 1;
rc = __damon_dbgfs_init();
if (rc) {
kfree(dbgfs_ctxs[0]);
kfree(dbgfs_ctxs);
pr_err("%s: dbgfs init failed\n", __func__);
}
out:
mutex_unlock(&damon_dbgfs_lock);
return rc;
}
module_init(damon_dbgfs_init);
#include "dbgfs-test.h"
| linux-master | mm/damon/dbgfs.c |
// SPDX-License-Identifier: GPL-2.0
/*
* DAMON sysfs Interface
*
* Copyright (c) 2022 SeongJae Park <[email protected]>
*/
#include <linux/pid.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include "sysfs-common.h"
/*
* init region directory
*/
struct damon_sysfs_region {
struct kobject kobj;
struct damon_addr_range ar;
};
static struct damon_sysfs_region *damon_sysfs_region_alloc(void)
{
return kzalloc(sizeof(struct damon_sysfs_region), GFP_KERNEL);
}
static ssize_t start_show(struct kobject *kobj, struct kobj_attribute *attr,
char *buf)
{
struct damon_sysfs_region *region = container_of(kobj,
struct damon_sysfs_region, kobj);
return sysfs_emit(buf, "%lu\n", region->ar.start);
}
static ssize_t start_store(struct kobject *kobj, struct kobj_attribute *attr,
const char *buf, size_t count)
{
struct damon_sysfs_region *region = container_of(kobj,
struct damon_sysfs_region, kobj);
int err = kstrtoul(buf, 0, ®ion->ar.start);
return err ? err : count;
}
static ssize_t end_show(struct kobject *kobj, struct kobj_attribute *attr,
char *buf)
{
struct damon_sysfs_region *region = container_of(kobj,
struct damon_sysfs_region, kobj);
return sysfs_emit(buf, "%lu\n", region->ar.end);
}
static ssize_t end_store(struct kobject *kobj, struct kobj_attribute *attr,
const char *buf, size_t count)
{
struct damon_sysfs_region *region = container_of(kobj,
struct damon_sysfs_region, kobj);
int err = kstrtoul(buf, 0, ®ion->ar.end);
return err ? err : count;
}
static void damon_sysfs_region_release(struct kobject *kobj)
{
kfree(container_of(kobj, struct damon_sysfs_region, kobj));
}
static struct kobj_attribute damon_sysfs_region_start_attr =
__ATTR_RW_MODE(start, 0600);
static struct kobj_attribute damon_sysfs_region_end_attr =
__ATTR_RW_MODE(end, 0600);
static struct attribute *damon_sysfs_region_attrs[] = {
&damon_sysfs_region_start_attr.attr,
&damon_sysfs_region_end_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(damon_sysfs_region);
static const struct kobj_type damon_sysfs_region_ktype = {
.release = damon_sysfs_region_release,
.sysfs_ops = &kobj_sysfs_ops,
.default_groups = damon_sysfs_region_groups,
};
/*
* init_regions directory
*/
struct damon_sysfs_regions {
struct kobject kobj;
struct damon_sysfs_region **regions_arr;
int nr;
};
static struct damon_sysfs_regions *damon_sysfs_regions_alloc(void)
{
return kzalloc(sizeof(struct damon_sysfs_regions), GFP_KERNEL);
}
static void damon_sysfs_regions_rm_dirs(struct damon_sysfs_regions *regions)
{
struct damon_sysfs_region **regions_arr = regions->regions_arr;
int i;
for (i = 0; i < regions->nr; i++)
kobject_put(®ions_arr[i]->kobj);
regions->nr = 0;
kfree(regions_arr);
regions->regions_arr = NULL;
}
static int damon_sysfs_regions_add_dirs(struct damon_sysfs_regions *regions,
int nr_regions)
{
struct damon_sysfs_region **regions_arr, *region;
int err, i;
damon_sysfs_regions_rm_dirs(regions);
if (!nr_regions)
return 0;
regions_arr = kmalloc_array(nr_regions, sizeof(*regions_arr),
GFP_KERNEL | __GFP_NOWARN);
if (!regions_arr)
return -ENOMEM;
regions->regions_arr = regions_arr;
for (i = 0; i < nr_regions; i++) {
region = damon_sysfs_region_alloc();
if (!region) {
damon_sysfs_regions_rm_dirs(regions);
return -ENOMEM;
}
err = kobject_init_and_add(®ion->kobj,
&damon_sysfs_region_ktype, ®ions->kobj,
"%d", i);
if (err) {
kobject_put(®ion->kobj);
damon_sysfs_regions_rm_dirs(regions);
return err;
}
regions_arr[i] = region;
regions->nr++;
}
return 0;
}
static ssize_t nr_regions_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_regions *regions = container_of(kobj,
struct damon_sysfs_regions, kobj);
return sysfs_emit(buf, "%d\n", regions->nr);
}
static ssize_t nr_regions_store(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf, size_t count)
{
struct damon_sysfs_regions *regions;
int nr, err = kstrtoint(buf, 0, &nr);
if (err)
return err;
if (nr < 0)
return -EINVAL;
regions = container_of(kobj, struct damon_sysfs_regions, kobj);
if (!mutex_trylock(&damon_sysfs_lock))
return -EBUSY;
err = damon_sysfs_regions_add_dirs(regions, nr);
mutex_unlock(&damon_sysfs_lock);
if (err)
return err;
return count;
}
static void damon_sysfs_regions_release(struct kobject *kobj)
{
kfree(container_of(kobj, struct damon_sysfs_regions, kobj));
}
static struct kobj_attribute damon_sysfs_regions_nr_attr =
__ATTR_RW_MODE(nr_regions, 0600);
static struct attribute *damon_sysfs_regions_attrs[] = {
&damon_sysfs_regions_nr_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(damon_sysfs_regions);
static const struct kobj_type damon_sysfs_regions_ktype = {
.release = damon_sysfs_regions_release,
.sysfs_ops = &kobj_sysfs_ops,
.default_groups = damon_sysfs_regions_groups,
};
/*
* target directory
*/
struct damon_sysfs_target {
struct kobject kobj;
struct damon_sysfs_regions *regions;
int pid;
};
static struct damon_sysfs_target *damon_sysfs_target_alloc(void)
{
return kzalloc(sizeof(struct damon_sysfs_target), GFP_KERNEL);
}
static int damon_sysfs_target_add_dirs(struct damon_sysfs_target *target)
{
struct damon_sysfs_regions *regions = damon_sysfs_regions_alloc();
int err;
if (!regions)
return -ENOMEM;
err = kobject_init_and_add(®ions->kobj, &damon_sysfs_regions_ktype,
&target->kobj, "regions");
if (err)
kobject_put(®ions->kobj);
else
target->regions = regions;
return err;
}
static void damon_sysfs_target_rm_dirs(struct damon_sysfs_target *target)
{
damon_sysfs_regions_rm_dirs(target->regions);
kobject_put(&target->regions->kobj);
}
static ssize_t pid_target_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_target *target = container_of(kobj,
struct damon_sysfs_target, kobj);
return sysfs_emit(buf, "%d\n", target->pid);
}
static ssize_t pid_target_store(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf, size_t count)
{
struct damon_sysfs_target *target = container_of(kobj,
struct damon_sysfs_target, kobj);
int err = kstrtoint(buf, 0, &target->pid);
if (err)
return -EINVAL;
return count;
}
static void damon_sysfs_target_release(struct kobject *kobj)
{
kfree(container_of(kobj, struct damon_sysfs_target, kobj));
}
static struct kobj_attribute damon_sysfs_target_pid_attr =
__ATTR_RW_MODE(pid_target, 0600);
static struct attribute *damon_sysfs_target_attrs[] = {
&damon_sysfs_target_pid_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(damon_sysfs_target);
static const struct kobj_type damon_sysfs_target_ktype = {
.release = damon_sysfs_target_release,
.sysfs_ops = &kobj_sysfs_ops,
.default_groups = damon_sysfs_target_groups,
};
/*
* targets directory
*/
struct damon_sysfs_targets {
struct kobject kobj;
struct damon_sysfs_target **targets_arr;
int nr;
};
static struct damon_sysfs_targets *damon_sysfs_targets_alloc(void)
{
return kzalloc(sizeof(struct damon_sysfs_targets), GFP_KERNEL);
}
static void damon_sysfs_targets_rm_dirs(struct damon_sysfs_targets *targets)
{
struct damon_sysfs_target **targets_arr = targets->targets_arr;
int i;
for (i = 0; i < targets->nr; i++) {
damon_sysfs_target_rm_dirs(targets_arr[i]);
kobject_put(&targets_arr[i]->kobj);
}
targets->nr = 0;
kfree(targets_arr);
targets->targets_arr = NULL;
}
static int damon_sysfs_targets_add_dirs(struct damon_sysfs_targets *targets,
int nr_targets)
{
struct damon_sysfs_target **targets_arr, *target;
int err, i;
damon_sysfs_targets_rm_dirs(targets);
if (!nr_targets)
return 0;
targets_arr = kmalloc_array(nr_targets, sizeof(*targets_arr),
GFP_KERNEL | __GFP_NOWARN);
if (!targets_arr)
return -ENOMEM;
targets->targets_arr = targets_arr;
for (i = 0; i < nr_targets; i++) {
target = damon_sysfs_target_alloc();
if (!target) {
damon_sysfs_targets_rm_dirs(targets);
return -ENOMEM;
}
err = kobject_init_and_add(&target->kobj,
&damon_sysfs_target_ktype, &targets->kobj,
"%d", i);
if (err)
goto out;
err = damon_sysfs_target_add_dirs(target);
if (err)
goto out;
targets_arr[i] = target;
targets->nr++;
}
return 0;
out:
damon_sysfs_targets_rm_dirs(targets);
kobject_put(&target->kobj);
return err;
}
static ssize_t nr_targets_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_targets *targets = container_of(kobj,
struct damon_sysfs_targets, kobj);
return sysfs_emit(buf, "%d\n", targets->nr);
}
static ssize_t nr_targets_store(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf, size_t count)
{
struct damon_sysfs_targets *targets;
int nr, err = kstrtoint(buf, 0, &nr);
if (err)
return err;
if (nr < 0)
return -EINVAL;
targets = container_of(kobj, struct damon_sysfs_targets, kobj);
if (!mutex_trylock(&damon_sysfs_lock))
return -EBUSY;
err = damon_sysfs_targets_add_dirs(targets, nr);
mutex_unlock(&damon_sysfs_lock);
if (err)
return err;
return count;
}
static void damon_sysfs_targets_release(struct kobject *kobj)
{
kfree(container_of(kobj, struct damon_sysfs_targets, kobj));
}
static struct kobj_attribute damon_sysfs_targets_nr_attr =
__ATTR_RW_MODE(nr_targets, 0600);
static struct attribute *damon_sysfs_targets_attrs[] = {
&damon_sysfs_targets_nr_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(damon_sysfs_targets);
static const struct kobj_type damon_sysfs_targets_ktype = {
.release = damon_sysfs_targets_release,
.sysfs_ops = &kobj_sysfs_ops,
.default_groups = damon_sysfs_targets_groups,
};
/*
* intervals directory
*/
struct damon_sysfs_intervals {
struct kobject kobj;
unsigned long sample_us;
unsigned long aggr_us;
unsigned long update_us;
};
static struct damon_sysfs_intervals *damon_sysfs_intervals_alloc(
unsigned long sample_us, unsigned long aggr_us,
unsigned long update_us)
{
struct damon_sysfs_intervals *intervals = kmalloc(sizeof(*intervals),
GFP_KERNEL);
if (!intervals)
return NULL;
intervals->kobj = (struct kobject){};
intervals->sample_us = sample_us;
intervals->aggr_us = aggr_us;
intervals->update_us = update_us;
return intervals;
}
static ssize_t sample_us_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_intervals *intervals = container_of(kobj,
struct damon_sysfs_intervals, kobj);
return sysfs_emit(buf, "%lu\n", intervals->sample_us);
}
static ssize_t sample_us_store(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf, size_t count)
{
struct damon_sysfs_intervals *intervals = container_of(kobj,
struct damon_sysfs_intervals, kobj);
unsigned long us;
int err = kstrtoul(buf, 0, &us);
if (err)
return err;
intervals->sample_us = us;
return count;
}
static ssize_t aggr_us_show(struct kobject *kobj, struct kobj_attribute *attr,
char *buf)
{
struct damon_sysfs_intervals *intervals = container_of(kobj,
struct damon_sysfs_intervals, kobj);
return sysfs_emit(buf, "%lu\n", intervals->aggr_us);
}
static ssize_t aggr_us_store(struct kobject *kobj, struct kobj_attribute *attr,
const char *buf, size_t count)
{
struct damon_sysfs_intervals *intervals = container_of(kobj,
struct damon_sysfs_intervals, kobj);
unsigned long us;
int err = kstrtoul(buf, 0, &us);
if (err)
return err;
intervals->aggr_us = us;
return count;
}
static ssize_t update_us_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_intervals *intervals = container_of(kobj,
struct damon_sysfs_intervals, kobj);
return sysfs_emit(buf, "%lu\n", intervals->update_us);
}
static ssize_t update_us_store(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf, size_t count)
{
struct damon_sysfs_intervals *intervals = container_of(kobj,
struct damon_sysfs_intervals, kobj);
unsigned long us;
int err = kstrtoul(buf, 0, &us);
if (err)
return err;
intervals->update_us = us;
return count;
}
static void damon_sysfs_intervals_release(struct kobject *kobj)
{
kfree(container_of(kobj, struct damon_sysfs_intervals, kobj));
}
static struct kobj_attribute damon_sysfs_intervals_sample_us_attr =
__ATTR_RW_MODE(sample_us, 0600);
static struct kobj_attribute damon_sysfs_intervals_aggr_us_attr =
__ATTR_RW_MODE(aggr_us, 0600);
static struct kobj_attribute damon_sysfs_intervals_update_us_attr =
__ATTR_RW_MODE(update_us, 0600);
static struct attribute *damon_sysfs_intervals_attrs[] = {
&damon_sysfs_intervals_sample_us_attr.attr,
&damon_sysfs_intervals_aggr_us_attr.attr,
&damon_sysfs_intervals_update_us_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(damon_sysfs_intervals);
static const struct kobj_type damon_sysfs_intervals_ktype = {
.release = damon_sysfs_intervals_release,
.sysfs_ops = &kobj_sysfs_ops,
.default_groups = damon_sysfs_intervals_groups,
};
/*
* monitoring_attrs directory
*/
struct damon_sysfs_attrs {
struct kobject kobj;
struct damon_sysfs_intervals *intervals;
struct damon_sysfs_ul_range *nr_regions_range;
};
static struct damon_sysfs_attrs *damon_sysfs_attrs_alloc(void)
{
struct damon_sysfs_attrs *attrs = kmalloc(sizeof(*attrs), GFP_KERNEL);
if (!attrs)
return NULL;
attrs->kobj = (struct kobject){};
return attrs;
}
static int damon_sysfs_attrs_add_dirs(struct damon_sysfs_attrs *attrs)
{
struct damon_sysfs_intervals *intervals;
struct damon_sysfs_ul_range *nr_regions_range;
int err;
intervals = damon_sysfs_intervals_alloc(5000, 100000, 60000000);
if (!intervals)
return -ENOMEM;
err = kobject_init_and_add(&intervals->kobj,
&damon_sysfs_intervals_ktype, &attrs->kobj,
"intervals");
if (err)
goto put_intervals_out;
attrs->intervals = intervals;
nr_regions_range = damon_sysfs_ul_range_alloc(10, 1000);
if (!nr_regions_range) {
err = -ENOMEM;
goto put_intervals_out;
}
err = kobject_init_and_add(&nr_regions_range->kobj,
&damon_sysfs_ul_range_ktype, &attrs->kobj,
"nr_regions");
if (err)
goto put_nr_regions_intervals_out;
attrs->nr_regions_range = nr_regions_range;
return 0;
put_nr_regions_intervals_out:
kobject_put(&nr_regions_range->kobj);
attrs->nr_regions_range = NULL;
put_intervals_out:
kobject_put(&intervals->kobj);
attrs->intervals = NULL;
return err;
}
static void damon_sysfs_attrs_rm_dirs(struct damon_sysfs_attrs *attrs)
{
kobject_put(&attrs->nr_regions_range->kobj);
kobject_put(&attrs->intervals->kobj);
}
static void damon_sysfs_attrs_release(struct kobject *kobj)
{
kfree(container_of(kobj, struct damon_sysfs_attrs, kobj));
}
static struct attribute *damon_sysfs_attrs_attrs[] = {
NULL,
};
ATTRIBUTE_GROUPS(damon_sysfs_attrs);
static const struct kobj_type damon_sysfs_attrs_ktype = {
.release = damon_sysfs_attrs_release,
.sysfs_ops = &kobj_sysfs_ops,
.default_groups = damon_sysfs_attrs_groups,
};
/*
* context directory
*/
/* This should match with enum damon_ops_id */
static const char * const damon_sysfs_ops_strs[] = {
"vaddr",
"fvaddr",
"paddr",
};
struct damon_sysfs_context {
struct kobject kobj;
enum damon_ops_id ops_id;
struct damon_sysfs_attrs *attrs;
struct damon_sysfs_targets *targets;
struct damon_sysfs_schemes *schemes;
};
static struct damon_sysfs_context *damon_sysfs_context_alloc(
enum damon_ops_id ops_id)
{
struct damon_sysfs_context *context = kmalloc(sizeof(*context),
GFP_KERNEL);
if (!context)
return NULL;
context->kobj = (struct kobject){};
context->ops_id = ops_id;
return context;
}
static int damon_sysfs_context_set_attrs(struct damon_sysfs_context *context)
{
struct damon_sysfs_attrs *attrs = damon_sysfs_attrs_alloc();
int err;
if (!attrs)
return -ENOMEM;
err = kobject_init_and_add(&attrs->kobj, &damon_sysfs_attrs_ktype,
&context->kobj, "monitoring_attrs");
if (err)
goto out;
err = damon_sysfs_attrs_add_dirs(attrs);
if (err)
goto out;
context->attrs = attrs;
return 0;
out:
kobject_put(&attrs->kobj);
return err;
}
static int damon_sysfs_context_set_targets(struct damon_sysfs_context *context)
{
struct damon_sysfs_targets *targets = damon_sysfs_targets_alloc();
int err;
if (!targets)
return -ENOMEM;
err = kobject_init_and_add(&targets->kobj, &damon_sysfs_targets_ktype,
&context->kobj, "targets");
if (err) {
kobject_put(&targets->kobj);
return err;
}
context->targets = targets;
return 0;
}
static int damon_sysfs_context_set_schemes(struct damon_sysfs_context *context)
{
struct damon_sysfs_schemes *schemes = damon_sysfs_schemes_alloc();
int err;
if (!schemes)
return -ENOMEM;
err = kobject_init_and_add(&schemes->kobj, &damon_sysfs_schemes_ktype,
&context->kobj, "schemes");
if (err) {
kobject_put(&schemes->kobj);
return err;
}
context->schemes = schemes;
return 0;
}
static int damon_sysfs_context_add_dirs(struct damon_sysfs_context *context)
{
int err;
err = damon_sysfs_context_set_attrs(context);
if (err)
return err;
err = damon_sysfs_context_set_targets(context);
if (err)
goto put_attrs_out;
err = damon_sysfs_context_set_schemes(context);
if (err)
goto put_targets_attrs_out;
return 0;
put_targets_attrs_out:
kobject_put(&context->targets->kobj);
context->targets = NULL;
put_attrs_out:
kobject_put(&context->attrs->kobj);
context->attrs = NULL;
return err;
}
static void damon_sysfs_context_rm_dirs(struct damon_sysfs_context *context)
{
damon_sysfs_attrs_rm_dirs(context->attrs);
kobject_put(&context->attrs->kobj);
damon_sysfs_targets_rm_dirs(context->targets);
kobject_put(&context->targets->kobj);
damon_sysfs_schemes_rm_dirs(context->schemes);
kobject_put(&context->schemes->kobj);
}
static ssize_t avail_operations_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
enum damon_ops_id id;
int len = 0;
for (id = 0; id < NR_DAMON_OPS; id++) {
if (!damon_is_registered_ops(id))
continue;
len += sysfs_emit_at(buf, len, "%s\n",
damon_sysfs_ops_strs[id]);
}
return len;
}
static ssize_t operations_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_context *context = container_of(kobj,
struct damon_sysfs_context, kobj);
return sysfs_emit(buf, "%s\n", damon_sysfs_ops_strs[context->ops_id]);
}
static ssize_t operations_store(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf, size_t count)
{
struct damon_sysfs_context *context = container_of(kobj,
struct damon_sysfs_context, kobj);
enum damon_ops_id id;
for (id = 0; id < NR_DAMON_OPS; id++) {
if (sysfs_streq(buf, damon_sysfs_ops_strs[id])) {
context->ops_id = id;
return count;
}
}
return -EINVAL;
}
static void damon_sysfs_context_release(struct kobject *kobj)
{
kfree(container_of(kobj, struct damon_sysfs_context, kobj));
}
static struct kobj_attribute damon_sysfs_context_avail_operations_attr =
__ATTR_RO_MODE(avail_operations, 0400);
static struct kobj_attribute damon_sysfs_context_operations_attr =
__ATTR_RW_MODE(operations, 0600);
static struct attribute *damon_sysfs_context_attrs[] = {
&damon_sysfs_context_avail_operations_attr.attr,
&damon_sysfs_context_operations_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(damon_sysfs_context);
static const struct kobj_type damon_sysfs_context_ktype = {
.release = damon_sysfs_context_release,
.sysfs_ops = &kobj_sysfs_ops,
.default_groups = damon_sysfs_context_groups,
};
/*
* contexts directory
*/
struct damon_sysfs_contexts {
struct kobject kobj;
struct damon_sysfs_context **contexts_arr;
int nr;
};
static struct damon_sysfs_contexts *damon_sysfs_contexts_alloc(void)
{
return kzalloc(sizeof(struct damon_sysfs_contexts), GFP_KERNEL);
}
static void damon_sysfs_contexts_rm_dirs(struct damon_sysfs_contexts *contexts)
{
struct damon_sysfs_context **contexts_arr = contexts->contexts_arr;
int i;
for (i = 0; i < contexts->nr; i++) {
damon_sysfs_context_rm_dirs(contexts_arr[i]);
kobject_put(&contexts_arr[i]->kobj);
}
contexts->nr = 0;
kfree(contexts_arr);
contexts->contexts_arr = NULL;
}
static int damon_sysfs_contexts_add_dirs(struct damon_sysfs_contexts *contexts,
int nr_contexts)
{
struct damon_sysfs_context **contexts_arr, *context;
int err, i;
damon_sysfs_contexts_rm_dirs(contexts);
if (!nr_contexts)
return 0;
contexts_arr = kmalloc_array(nr_contexts, sizeof(*contexts_arr),
GFP_KERNEL | __GFP_NOWARN);
if (!contexts_arr)
return -ENOMEM;
contexts->contexts_arr = contexts_arr;
for (i = 0; i < nr_contexts; i++) {
context = damon_sysfs_context_alloc(DAMON_OPS_VADDR);
if (!context) {
damon_sysfs_contexts_rm_dirs(contexts);
return -ENOMEM;
}
err = kobject_init_and_add(&context->kobj,
&damon_sysfs_context_ktype, &contexts->kobj,
"%d", i);
if (err)
goto out;
err = damon_sysfs_context_add_dirs(context);
if (err)
goto out;
contexts_arr[i] = context;
contexts->nr++;
}
return 0;
out:
damon_sysfs_contexts_rm_dirs(contexts);
kobject_put(&context->kobj);
return err;
}
static ssize_t nr_contexts_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_contexts *contexts = container_of(kobj,
struct damon_sysfs_contexts, kobj);
return sysfs_emit(buf, "%d\n", contexts->nr);
}
static ssize_t nr_contexts_store(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf, size_t count)
{
struct damon_sysfs_contexts *contexts;
int nr, err;
err = kstrtoint(buf, 0, &nr);
if (err)
return err;
/* TODO: support multiple contexts per kdamond */
if (nr < 0 || 1 < nr)
return -EINVAL;
contexts = container_of(kobj, struct damon_sysfs_contexts, kobj);
if (!mutex_trylock(&damon_sysfs_lock))
return -EBUSY;
err = damon_sysfs_contexts_add_dirs(contexts, nr);
mutex_unlock(&damon_sysfs_lock);
if (err)
return err;
return count;
}
static void damon_sysfs_contexts_release(struct kobject *kobj)
{
kfree(container_of(kobj, struct damon_sysfs_contexts, kobj));
}
static struct kobj_attribute damon_sysfs_contexts_nr_attr
= __ATTR_RW_MODE(nr_contexts, 0600);
static struct attribute *damon_sysfs_contexts_attrs[] = {
&damon_sysfs_contexts_nr_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(damon_sysfs_contexts);
static const struct kobj_type damon_sysfs_contexts_ktype = {
.release = damon_sysfs_contexts_release,
.sysfs_ops = &kobj_sysfs_ops,
.default_groups = damon_sysfs_contexts_groups,
};
/*
* kdamond directory
*/
struct damon_sysfs_kdamond {
struct kobject kobj;
struct damon_sysfs_contexts *contexts;
struct damon_ctx *damon_ctx;
};
static struct damon_sysfs_kdamond *damon_sysfs_kdamond_alloc(void)
{
return kzalloc(sizeof(struct damon_sysfs_kdamond), GFP_KERNEL);
}
static int damon_sysfs_kdamond_add_dirs(struct damon_sysfs_kdamond *kdamond)
{
struct damon_sysfs_contexts *contexts;
int err;
contexts = damon_sysfs_contexts_alloc();
if (!contexts)
return -ENOMEM;
err = kobject_init_and_add(&contexts->kobj,
&damon_sysfs_contexts_ktype, &kdamond->kobj,
"contexts");
if (err) {
kobject_put(&contexts->kobj);
return err;
}
kdamond->contexts = contexts;
return err;
}
static void damon_sysfs_kdamond_rm_dirs(struct damon_sysfs_kdamond *kdamond)
{
damon_sysfs_contexts_rm_dirs(kdamond->contexts);
kobject_put(&kdamond->contexts->kobj);
}
static bool damon_sysfs_ctx_running(struct damon_ctx *ctx)
{
bool running;
mutex_lock(&ctx->kdamond_lock);
running = ctx->kdamond != NULL;
mutex_unlock(&ctx->kdamond_lock);
return running;
}
/*
* enum damon_sysfs_cmd - Commands for a specific kdamond.
*/
enum damon_sysfs_cmd {
/* @DAMON_SYSFS_CMD_ON: Turn the kdamond on. */
DAMON_SYSFS_CMD_ON,
/* @DAMON_SYSFS_CMD_OFF: Turn the kdamond off. */
DAMON_SYSFS_CMD_OFF,
/* @DAMON_SYSFS_CMD_COMMIT: Update kdamond inputs. */
DAMON_SYSFS_CMD_COMMIT,
/*
* @DAMON_SYSFS_CMD_UPDATE_SCHEMES_STATS: Update scheme stats sysfs
* files.
*/
DAMON_SYSFS_CMD_UPDATE_SCHEMES_STATS,
/*
* @DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_BYTES: Update
* tried_regions/total_bytes sysfs files for each scheme.
*/
DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_BYTES,
/*
* @DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_REGIONS: Update schemes tried
* regions
*/
DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_REGIONS,
/*
* @DAMON_SYSFS_CMD_CLEAR_SCHEMES_TRIED_REGIONS: Clear schemes tried
* regions
*/
DAMON_SYSFS_CMD_CLEAR_SCHEMES_TRIED_REGIONS,
/*
* @NR_DAMON_SYSFS_CMDS: Total number of DAMON sysfs commands.
*/
NR_DAMON_SYSFS_CMDS,
};
/* Should match with enum damon_sysfs_cmd */
static const char * const damon_sysfs_cmd_strs[] = {
"on",
"off",
"commit",
"update_schemes_stats",
"update_schemes_tried_bytes",
"update_schemes_tried_regions",
"clear_schemes_tried_regions",
};
/*
* struct damon_sysfs_cmd_request - A request to the DAMON callback.
* @cmd: The command that needs to be handled by the callback.
* @kdamond: The kobject wrapper that associated to the kdamond thread.
*
* This structure represents a sysfs command request that need to access some
* DAMON context-internal data. Because DAMON context-internal data can be
* safely accessed from DAMON callbacks without additional synchronization, the
* request will be handled by the DAMON callback. None-``NULL`` @kdamond means
* the request is valid.
*/
struct damon_sysfs_cmd_request {
enum damon_sysfs_cmd cmd;
struct damon_sysfs_kdamond *kdamond;
};
/* Current DAMON callback request. Protected by damon_sysfs_lock. */
static struct damon_sysfs_cmd_request damon_sysfs_cmd_request;
static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
char *buf)
{
struct damon_sysfs_kdamond *kdamond = container_of(kobj,
struct damon_sysfs_kdamond, kobj);
struct damon_ctx *ctx = kdamond->damon_ctx;
bool running;
if (!ctx)
running = false;
else
running = damon_sysfs_ctx_running(ctx);
return sysfs_emit(buf, "%s\n", running ?
damon_sysfs_cmd_strs[DAMON_SYSFS_CMD_ON] :
damon_sysfs_cmd_strs[DAMON_SYSFS_CMD_OFF]);
}
static int damon_sysfs_set_attrs(struct damon_ctx *ctx,
struct damon_sysfs_attrs *sys_attrs)
{
struct damon_sysfs_intervals *sys_intervals = sys_attrs->intervals;
struct damon_sysfs_ul_range *sys_nr_regions =
sys_attrs->nr_regions_range;
struct damon_attrs attrs = {
.sample_interval = sys_intervals->sample_us,
.aggr_interval = sys_intervals->aggr_us,
.ops_update_interval = sys_intervals->update_us,
.min_nr_regions = sys_nr_regions->min,
.max_nr_regions = sys_nr_regions->max,
};
return damon_set_attrs(ctx, &attrs);
}
static void damon_sysfs_destroy_targets(struct damon_ctx *ctx)
{
struct damon_target *t, *next;
bool has_pid = damon_target_has_pid(ctx);
damon_for_each_target_safe(t, next, ctx) {
if (has_pid)
put_pid(t->pid);
damon_destroy_target(t);
}
}
static int damon_sysfs_set_regions(struct damon_target *t,
struct damon_sysfs_regions *sysfs_regions)
{
struct damon_addr_range *ranges = kmalloc_array(sysfs_regions->nr,
sizeof(*ranges), GFP_KERNEL | __GFP_NOWARN);
int i, err = -EINVAL;
if (!ranges)
return -ENOMEM;
for (i = 0; i < sysfs_regions->nr; i++) {
struct damon_sysfs_region *sys_region =
sysfs_regions->regions_arr[i];
if (sys_region->ar.start > sys_region->ar.end)
goto out;
ranges[i].start = sys_region->ar.start;
ranges[i].end = sys_region->ar.end;
if (i == 0)
continue;
if (ranges[i - 1].end > ranges[i].start)
goto out;
}
err = damon_set_regions(t, ranges, sysfs_regions->nr);
out:
kfree(ranges);
return err;
}
static int damon_sysfs_add_target(struct damon_sysfs_target *sys_target,
struct damon_ctx *ctx)
{
struct damon_target *t = damon_new_target();
int err = -EINVAL;
if (!t)
return -ENOMEM;
damon_add_target(ctx, t);
if (damon_target_has_pid(ctx)) {
t->pid = find_get_pid(sys_target->pid);
if (!t->pid)
goto destroy_targets_out;
}
err = damon_sysfs_set_regions(t, sys_target->regions);
if (err)
goto destroy_targets_out;
return 0;
destroy_targets_out:
damon_sysfs_destroy_targets(ctx);
return err;
}
/*
* Search a target in a context that corresponds to the sysfs target input.
*
* Return: pointer to the target if found, NULL if not found, or negative
* error code if the search failed.
*/
static struct damon_target *damon_sysfs_existing_target(
struct damon_sysfs_target *sys_target, struct damon_ctx *ctx)
{
struct pid *pid;
struct damon_target *t;
if (!damon_target_has_pid(ctx)) {
/* Up to only one target for paddr could exist */
damon_for_each_target(t, ctx)
return t;
return NULL;
}
/* ops.id should be DAMON_OPS_VADDR or DAMON_OPS_FVADDR */
pid = find_get_pid(sys_target->pid);
if (!pid)
return ERR_PTR(-EINVAL);
damon_for_each_target(t, ctx) {
if (t->pid == pid) {
put_pid(pid);
return t;
}
}
put_pid(pid);
return NULL;
}
static int damon_sysfs_set_targets(struct damon_ctx *ctx,
struct damon_sysfs_targets *sysfs_targets)
{
int i, err;
/* Multiple physical address space monitoring targets makes no sense */
if (ctx->ops.id == DAMON_OPS_PADDR && sysfs_targets->nr > 1)
return -EINVAL;
for (i = 0; i < sysfs_targets->nr; i++) {
struct damon_sysfs_target *st = sysfs_targets->targets_arr[i];
struct damon_target *t = damon_sysfs_existing_target(st, ctx);
if (IS_ERR(t))
return PTR_ERR(t);
if (!t)
err = damon_sysfs_add_target(st, ctx);
else
err = damon_sysfs_set_regions(t, st->regions);
if (err)
return err;
}
return 0;
}
static void damon_sysfs_before_terminate(struct damon_ctx *ctx)
{
struct damon_target *t, *next;
struct damon_sysfs_kdamond *kdamond;
enum damon_sysfs_cmd cmd;
/* damon_sysfs_schemes_update_regions_stop() might not yet called */
kdamond = damon_sysfs_cmd_request.kdamond;
cmd = damon_sysfs_cmd_request.cmd;
if (kdamond && ctx == kdamond->damon_ctx &&
(cmd == DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_REGIONS ||
cmd == DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_BYTES)) {
damon_sysfs_schemes_update_regions_stop(ctx);
mutex_unlock(&damon_sysfs_lock);
}
if (!damon_target_has_pid(ctx))
return;
mutex_lock(&ctx->kdamond_lock);
damon_for_each_target_safe(t, next, ctx) {
put_pid(t->pid);
damon_destroy_target(t);
}
mutex_unlock(&ctx->kdamond_lock);
}
/*
* damon_sysfs_upd_schemes_stats() - Update schemes stats sysfs files.
* @kdamond: The kobject wrapper that associated to the kdamond thread.
*
* This function reads the schemes stats of specific kdamond and update the
* related values for sysfs files. This function should be called from DAMON
* callbacks while holding ``damon_syfs_lock``, to safely access the DAMON
* contexts-internal data and DAMON sysfs variables.
*/
static int damon_sysfs_upd_schemes_stats(struct damon_sysfs_kdamond *kdamond)
{
struct damon_ctx *ctx = kdamond->damon_ctx;
if (!ctx)
return -EINVAL;
damon_sysfs_schemes_update_stats(
kdamond->contexts->contexts_arr[0]->schemes, ctx);
return 0;
}
static int damon_sysfs_upd_schemes_regions_start(
struct damon_sysfs_kdamond *kdamond, bool total_bytes_only)
{
struct damon_ctx *ctx = kdamond->damon_ctx;
if (!ctx)
return -EINVAL;
return damon_sysfs_schemes_update_regions_start(
kdamond->contexts->contexts_arr[0]->schemes, ctx,
total_bytes_only);
}
static int damon_sysfs_upd_schemes_regions_stop(
struct damon_sysfs_kdamond *kdamond)
{
struct damon_ctx *ctx = kdamond->damon_ctx;
if (!ctx)
return -EINVAL;
return damon_sysfs_schemes_update_regions_stop(ctx);
}
static int damon_sysfs_clear_schemes_regions(
struct damon_sysfs_kdamond *kdamond)
{
struct damon_ctx *ctx = kdamond->damon_ctx;
if (!ctx)
return -EINVAL;
return damon_sysfs_schemes_clear_regions(
kdamond->contexts->contexts_arr[0]->schemes, ctx);
}
static inline bool damon_sysfs_kdamond_running(
struct damon_sysfs_kdamond *kdamond)
{
return kdamond->damon_ctx &&
damon_sysfs_ctx_running(kdamond->damon_ctx);
}
static int damon_sysfs_apply_inputs(struct damon_ctx *ctx,
struct damon_sysfs_context *sys_ctx)
{
int err;
err = damon_select_ops(ctx, sys_ctx->ops_id);
if (err)
return err;
err = damon_sysfs_set_attrs(ctx, sys_ctx->attrs);
if (err)
return err;
err = damon_sysfs_set_targets(ctx, sys_ctx->targets);
if (err)
return err;
return damon_sysfs_set_schemes(ctx, sys_ctx->schemes);
}
/*
* damon_sysfs_commit_input() - Commit user inputs to a running kdamond.
* @kdamond: The kobject wrapper for the associated kdamond.
*
* If the sysfs input is wrong, the kdamond will be terminated.
*/
static int damon_sysfs_commit_input(struct damon_sysfs_kdamond *kdamond)
{
if (!damon_sysfs_kdamond_running(kdamond))
return -EINVAL;
/* TODO: Support multiple contexts per kdamond */
if (kdamond->contexts->nr != 1)
return -EINVAL;
return damon_sysfs_apply_inputs(kdamond->damon_ctx,
kdamond->contexts->contexts_arr[0]);
}
/*
* damon_sysfs_cmd_request_callback() - DAMON callback for handling requests.
* @c: The DAMON context of the callback.
*
* This function is periodically called back from the kdamond thread for @c.
* Then, it checks if there is a waiting DAMON sysfs request and handles it.
*/
static int damon_sysfs_cmd_request_callback(struct damon_ctx *c)
{
struct damon_sysfs_kdamond *kdamond;
static bool damon_sysfs_schemes_regions_updating;
bool total_bytes_only = false;
int err = 0;
/* avoid deadlock due to concurrent state_store('off') */
if (!damon_sysfs_schemes_regions_updating &&
!mutex_trylock(&damon_sysfs_lock))
return 0;
kdamond = damon_sysfs_cmd_request.kdamond;
if (!kdamond || kdamond->damon_ctx != c)
goto out;
switch (damon_sysfs_cmd_request.cmd) {
case DAMON_SYSFS_CMD_UPDATE_SCHEMES_STATS:
err = damon_sysfs_upd_schemes_stats(kdamond);
break;
case DAMON_SYSFS_CMD_COMMIT:
err = damon_sysfs_commit_input(kdamond);
break;
case DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_BYTES:
total_bytes_only = true;
fallthrough;
case DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_REGIONS:
if (!damon_sysfs_schemes_regions_updating) {
err = damon_sysfs_upd_schemes_regions_start(kdamond,
total_bytes_only);
if (!err) {
damon_sysfs_schemes_regions_updating = true;
goto keep_lock_out;
}
} else {
err = damon_sysfs_upd_schemes_regions_stop(kdamond);
damon_sysfs_schemes_regions_updating = false;
}
break;
case DAMON_SYSFS_CMD_CLEAR_SCHEMES_TRIED_REGIONS:
err = damon_sysfs_clear_schemes_regions(kdamond);
break;
default:
break;
}
/* Mark the request as invalid now. */
damon_sysfs_cmd_request.kdamond = NULL;
out:
if (!damon_sysfs_schemes_regions_updating)
mutex_unlock(&damon_sysfs_lock);
keep_lock_out:
return err;
}
static struct damon_ctx *damon_sysfs_build_ctx(
struct damon_sysfs_context *sys_ctx)
{
struct damon_ctx *ctx = damon_new_ctx();
int err;
if (!ctx)
return ERR_PTR(-ENOMEM);
err = damon_sysfs_apply_inputs(ctx, sys_ctx);
if (err) {
damon_destroy_ctx(ctx);
return ERR_PTR(err);
}
ctx->callback.after_wmarks_check = damon_sysfs_cmd_request_callback;
ctx->callback.after_aggregation = damon_sysfs_cmd_request_callback;
ctx->callback.before_terminate = damon_sysfs_before_terminate;
return ctx;
}
static int damon_sysfs_turn_damon_on(struct damon_sysfs_kdamond *kdamond)
{
struct damon_ctx *ctx;
int err;
if (damon_sysfs_kdamond_running(kdamond))
return -EBUSY;
if (damon_sysfs_cmd_request.kdamond == kdamond)
return -EBUSY;
/* TODO: support multiple contexts per kdamond */
if (kdamond->contexts->nr != 1)
return -EINVAL;
if (kdamond->damon_ctx)
damon_destroy_ctx(kdamond->damon_ctx);
kdamond->damon_ctx = NULL;
ctx = damon_sysfs_build_ctx(kdamond->contexts->contexts_arr[0]);
if (IS_ERR(ctx))
return PTR_ERR(ctx);
err = damon_start(&ctx, 1, false);
if (err) {
damon_destroy_ctx(ctx);
return err;
}
kdamond->damon_ctx = ctx;
return err;
}
static int damon_sysfs_turn_damon_off(struct damon_sysfs_kdamond *kdamond)
{
if (!kdamond->damon_ctx)
return -EINVAL;
return damon_stop(&kdamond->damon_ctx, 1);
/*
* To allow users show final monitoring results of already turned-off
* DAMON, we free kdamond->damon_ctx in next
* damon_sysfs_turn_damon_on(), or kdamonds_nr_store()
*/
}
/*
* damon_sysfs_handle_cmd() - Handle a command for a specific kdamond.
* @cmd: The command to handle.
* @kdamond: The kobject wrapper for the associated kdamond.
*
* This function handles a DAMON sysfs command for a kdamond. For commands
* that need to access running DAMON context-internal data, it requests
* handling of the command to the DAMON callback
* (@damon_sysfs_cmd_request_callback()) and wait until it is properly handled,
* or the context is completed.
*
* Return: 0 on success, negative error code otherwise.
*/
static int damon_sysfs_handle_cmd(enum damon_sysfs_cmd cmd,
struct damon_sysfs_kdamond *kdamond)
{
bool need_wait = true;
/* Handle commands that doesn't access DAMON context-internal data */
switch (cmd) {
case DAMON_SYSFS_CMD_ON:
return damon_sysfs_turn_damon_on(kdamond);
case DAMON_SYSFS_CMD_OFF:
return damon_sysfs_turn_damon_off(kdamond);
default:
break;
}
/* Pass the command to DAMON callback for safe DAMON context access */
if (damon_sysfs_cmd_request.kdamond)
return -EBUSY;
if (!damon_sysfs_kdamond_running(kdamond))
return -EINVAL;
damon_sysfs_cmd_request.cmd = cmd;
damon_sysfs_cmd_request.kdamond = kdamond;
/*
* wait until damon_sysfs_cmd_request_callback() handles the request
* from kdamond context
*/
mutex_unlock(&damon_sysfs_lock);
while (need_wait) {
schedule_timeout_idle(msecs_to_jiffies(100));
if (!mutex_trylock(&damon_sysfs_lock))
continue;
if (!damon_sysfs_cmd_request.kdamond) {
/* damon_sysfs_cmd_request_callback() handled */
need_wait = false;
} else if (!damon_sysfs_kdamond_running(kdamond)) {
/* kdamond has already finished */
need_wait = false;
damon_sysfs_cmd_request.kdamond = NULL;
}
mutex_unlock(&damon_sysfs_lock);
}
mutex_lock(&damon_sysfs_lock);
return 0;
}
static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
const char *buf, size_t count)
{
struct damon_sysfs_kdamond *kdamond = container_of(kobj,
struct damon_sysfs_kdamond, kobj);
enum damon_sysfs_cmd cmd;
ssize_t ret = -EINVAL;
if (!mutex_trylock(&damon_sysfs_lock))
return -EBUSY;
for (cmd = 0; cmd < NR_DAMON_SYSFS_CMDS; cmd++) {
if (sysfs_streq(buf, damon_sysfs_cmd_strs[cmd])) {
ret = damon_sysfs_handle_cmd(cmd, kdamond);
break;
}
}
mutex_unlock(&damon_sysfs_lock);
if (!ret)
ret = count;
return ret;
}
static ssize_t pid_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_kdamond *kdamond = container_of(kobj,
struct damon_sysfs_kdamond, kobj);
struct damon_ctx *ctx;
int pid = -1;
if (!mutex_trylock(&damon_sysfs_lock))
return -EBUSY;
ctx = kdamond->damon_ctx;
if (!ctx)
goto out;
mutex_lock(&ctx->kdamond_lock);
if (ctx->kdamond)
pid = ctx->kdamond->pid;
mutex_unlock(&ctx->kdamond_lock);
out:
mutex_unlock(&damon_sysfs_lock);
return sysfs_emit(buf, "%d\n", pid);
}
static void damon_sysfs_kdamond_release(struct kobject *kobj)
{
struct damon_sysfs_kdamond *kdamond = container_of(kobj,
struct damon_sysfs_kdamond, kobj);
if (kdamond->damon_ctx)
damon_destroy_ctx(kdamond->damon_ctx);
kfree(kdamond);
}
static struct kobj_attribute damon_sysfs_kdamond_state_attr =
__ATTR_RW_MODE(state, 0600);
static struct kobj_attribute damon_sysfs_kdamond_pid_attr =
__ATTR_RO_MODE(pid, 0400);
static struct attribute *damon_sysfs_kdamond_attrs[] = {
&damon_sysfs_kdamond_state_attr.attr,
&damon_sysfs_kdamond_pid_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(damon_sysfs_kdamond);
static const struct kobj_type damon_sysfs_kdamond_ktype = {
.release = damon_sysfs_kdamond_release,
.sysfs_ops = &kobj_sysfs_ops,
.default_groups = damon_sysfs_kdamond_groups,
};
/*
* kdamonds directory
*/
struct damon_sysfs_kdamonds {
struct kobject kobj;
struct damon_sysfs_kdamond **kdamonds_arr;
int nr;
};
static struct damon_sysfs_kdamonds *damon_sysfs_kdamonds_alloc(void)
{
return kzalloc(sizeof(struct damon_sysfs_kdamonds), GFP_KERNEL);
}
static void damon_sysfs_kdamonds_rm_dirs(struct damon_sysfs_kdamonds *kdamonds)
{
struct damon_sysfs_kdamond **kdamonds_arr = kdamonds->kdamonds_arr;
int i;
for (i = 0; i < kdamonds->nr; i++) {
damon_sysfs_kdamond_rm_dirs(kdamonds_arr[i]);
kobject_put(&kdamonds_arr[i]->kobj);
}
kdamonds->nr = 0;
kfree(kdamonds_arr);
kdamonds->kdamonds_arr = NULL;
}
static bool damon_sysfs_kdamonds_busy(struct damon_sysfs_kdamond **kdamonds,
int nr_kdamonds)
{
int i;
for (i = 0; i < nr_kdamonds; i++) {
if (damon_sysfs_kdamond_running(kdamonds[i]) ||
damon_sysfs_cmd_request.kdamond == kdamonds[i])
return true;
}
return false;
}
static int damon_sysfs_kdamonds_add_dirs(struct damon_sysfs_kdamonds *kdamonds,
int nr_kdamonds)
{
struct damon_sysfs_kdamond **kdamonds_arr, *kdamond;
int err, i;
if (damon_sysfs_kdamonds_busy(kdamonds->kdamonds_arr, kdamonds->nr))
return -EBUSY;
damon_sysfs_kdamonds_rm_dirs(kdamonds);
if (!nr_kdamonds)
return 0;
kdamonds_arr = kmalloc_array(nr_kdamonds, sizeof(*kdamonds_arr),
GFP_KERNEL | __GFP_NOWARN);
if (!kdamonds_arr)
return -ENOMEM;
kdamonds->kdamonds_arr = kdamonds_arr;
for (i = 0; i < nr_kdamonds; i++) {
kdamond = damon_sysfs_kdamond_alloc();
if (!kdamond) {
damon_sysfs_kdamonds_rm_dirs(kdamonds);
return -ENOMEM;
}
err = kobject_init_and_add(&kdamond->kobj,
&damon_sysfs_kdamond_ktype, &kdamonds->kobj,
"%d", i);
if (err)
goto out;
err = damon_sysfs_kdamond_add_dirs(kdamond);
if (err)
goto out;
kdamonds_arr[i] = kdamond;
kdamonds->nr++;
}
return 0;
out:
damon_sysfs_kdamonds_rm_dirs(kdamonds);
kobject_put(&kdamond->kobj);
return err;
}
static ssize_t nr_kdamonds_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct damon_sysfs_kdamonds *kdamonds = container_of(kobj,
struct damon_sysfs_kdamonds, kobj);
return sysfs_emit(buf, "%d\n", kdamonds->nr);
}
static ssize_t nr_kdamonds_store(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf, size_t count)
{
struct damon_sysfs_kdamonds *kdamonds;
int nr, err;
err = kstrtoint(buf, 0, &nr);
if (err)
return err;
if (nr < 0)
return -EINVAL;
kdamonds = container_of(kobj, struct damon_sysfs_kdamonds, kobj);
if (!mutex_trylock(&damon_sysfs_lock))
return -EBUSY;
err = damon_sysfs_kdamonds_add_dirs(kdamonds, nr);
mutex_unlock(&damon_sysfs_lock);
if (err)
return err;
return count;
}
static void damon_sysfs_kdamonds_release(struct kobject *kobj)
{
kfree(container_of(kobj, struct damon_sysfs_kdamonds, kobj));
}
static struct kobj_attribute damon_sysfs_kdamonds_nr_attr =
__ATTR_RW_MODE(nr_kdamonds, 0600);
static struct attribute *damon_sysfs_kdamonds_attrs[] = {
&damon_sysfs_kdamonds_nr_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(damon_sysfs_kdamonds);
static const struct kobj_type damon_sysfs_kdamonds_ktype = {
.release = damon_sysfs_kdamonds_release,
.sysfs_ops = &kobj_sysfs_ops,
.default_groups = damon_sysfs_kdamonds_groups,
};
/*
* damon user interface directory
*/
struct damon_sysfs_ui_dir {
struct kobject kobj;
struct damon_sysfs_kdamonds *kdamonds;
};
static struct damon_sysfs_ui_dir *damon_sysfs_ui_dir_alloc(void)
{
return kzalloc(sizeof(struct damon_sysfs_ui_dir), GFP_KERNEL);
}
static int damon_sysfs_ui_dir_add_dirs(struct damon_sysfs_ui_dir *ui_dir)
{
struct damon_sysfs_kdamonds *kdamonds;
int err;
kdamonds = damon_sysfs_kdamonds_alloc();
if (!kdamonds)
return -ENOMEM;
err = kobject_init_and_add(&kdamonds->kobj,
&damon_sysfs_kdamonds_ktype, &ui_dir->kobj,
"kdamonds");
if (err) {
kobject_put(&kdamonds->kobj);
return err;
}
ui_dir->kdamonds = kdamonds;
return err;
}
static void damon_sysfs_ui_dir_release(struct kobject *kobj)
{
kfree(container_of(kobj, struct damon_sysfs_ui_dir, kobj));
}
static struct attribute *damon_sysfs_ui_dir_attrs[] = {
NULL,
};
ATTRIBUTE_GROUPS(damon_sysfs_ui_dir);
static const struct kobj_type damon_sysfs_ui_dir_ktype = {
.release = damon_sysfs_ui_dir_release,
.sysfs_ops = &kobj_sysfs_ops,
.default_groups = damon_sysfs_ui_dir_groups,
};
static int __init damon_sysfs_init(void)
{
struct kobject *damon_sysfs_root;
struct damon_sysfs_ui_dir *admin;
int err;
damon_sysfs_root = kobject_create_and_add("damon", mm_kobj);
if (!damon_sysfs_root)
return -ENOMEM;
admin = damon_sysfs_ui_dir_alloc();
if (!admin) {
kobject_put(damon_sysfs_root);
return -ENOMEM;
}
err = kobject_init_and_add(&admin->kobj, &damon_sysfs_ui_dir_ktype,
damon_sysfs_root, "admin");
if (err)
goto out;
err = damon_sysfs_ui_dir_add_dirs(admin);
if (err)
goto out;
return 0;
out:
kobject_put(&admin->kobj);
kobject_put(damon_sysfs_root);
return err;
}
subsys_initcall(damon_sysfs_init);
| linux-master | mm/damon/sysfs.c |
// SPDX-License-Identifier: GPL-2.0
/*
* DAMON Primitives for The Physical Address Space
*
* Author: SeongJae Park <[email protected]>
*/
#define pr_fmt(fmt) "damon-pa: " fmt
#include <linux/mmu_notifier.h>
#include <linux/page_idle.h>
#include <linux/pagemap.h>
#include <linux/rmap.h>
#include <linux/swap.h>
#include "../internal.h"
#include "ops-common.h"
static bool __damon_pa_mkold(struct folio *folio, struct vm_area_struct *vma,
unsigned long addr, void *arg)
{
DEFINE_FOLIO_VMA_WALK(pvmw, folio, vma, addr, 0);
while (page_vma_mapped_walk(&pvmw)) {
addr = pvmw.address;
if (pvmw.pte)
damon_ptep_mkold(pvmw.pte, vma, addr);
else
damon_pmdp_mkold(pvmw.pmd, vma, addr);
}
return true;
}
static void damon_pa_mkold(unsigned long paddr)
{
struct folio *folio = damon_get_folio(PHYS_PFN(paddr));
struct rmap_walk_control rwc = {
.rmap_one = __damon_pa_mkold,
.anon_lock = folio_lock_anon_vma_read,
};
bool need_lock;
if (!folio)
return;
if (!folio_mapped(folio) || !folio_raw_mapping(folio)) {
folio_set_idle(folio);
goto out;
}
need_lock = !folio_test_anon(folio) || folio_test_ksm(folio);
if (need_lock && !folio_trylock(folio))
goto out;
rmap_walk(folio, &rwc);
if (need_lock)
folio_unlock(folio);
out:
folio_put(folio);
}
static void __damon_pa_prepare_access_check(struct damon_region *r)
{
r->sampling_addr = damon_rand(r->ar.start, r->ar.end);
damon_pa_mkold(r->sampling_addr);
}
static void damon_pa_prepare_access_checks(struct damon_ctx *ctx)
{
struct damon_target *t;
struct damon_region *r;
damon_for_each_target(t, ctx) {
damon_for_each_region(r, t)
__damon_pa_prepare_access_check(r);
}
}
static bool __damon_pa_young(struct folio *folio, struct vm_area_struct *vma,
unsigned long addr, void *arg)
{
bool *accessed = arg;
DEFINE_FOLIO_VMA_WALK(pvmw, folio, vma, addr, 0);
*accessed = false;
while (page_vma_mapped_walk(&pvmw)) {
addr = pvmw.address;
if (pvmw.pte) {
*accessed = pte_young(ptep_get(pvmw.pte)) ||
!folio_test_idle(folio) ||
mmu_notifier_test_young(vma->vm_mm, addr);
} else {
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
*accessed = pmd_young(pmdp_get(pvmw.pmd)) ||
!folio_test_idle(folio) ||
mmu_notifier_test_young(vma->vm_mm, addr);
#else
WARN_ON_ONCE(1);
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
}
if (*accessed) {
page_vma_mapped_walk_done(&pvmw);
break;
}
}
/* If accessed, stop walking */
return *accessed == false;
}
static bool damon_pa_young(unsigned long paddr, unsigned long *folio_sz)
{
struct folio *folio = damon_get_folio(PHYS_PFN(paddr));
bool accessed = false;
struct rmap_walk_control rwc = {
.arg = &accessed,
.rmap_one = __damon_pa_young,
.anon_lock = folio_lock_anon_vma_read,
};
bool need_lock;
if (!folio)
return false;
if (!folio_mapped(folio) || !folio_raw_mapping(folio)) {
if (folio_test_idle(folio))
accessed = false;
else
accessed = true;
goto out;
}
need_lock = !folio_test_anon(folio) || folio_test_ksm(folio);
if (need_lock && !folio_trylock(folio))
goto out;
rmap_walk(folio, &rwc);
if (need_lock)
folio_unlock(folio);
out:
*folio_sz = folio_size(folio);
folio_put(folio);
return accessed;
}
static void __damon_pa_check_access(struct damon_region *r)
{
static unsigned long last_addr;
static unsigned long last_folio_sz = PAGE_SIZE;
static bool last_accessed;
/* If the region is in the last checked page, reuse the result */
if (ALIGN_DOWN(last_addr, last_folio_sz) ==
ALIGN_DOWN(r->sampling_addr, last_folio_sz)) {
if (last_accessed)
r->nr_accesses++;
return;
}
last_accessed = damon_pa_young(r->sampling_addr, &last_folio_sz);
if (last_accessed)
r->nr_accesses++;
last_addr = r->sampling_addr;
}
static unsigned int damon_pa_check_accesses(struct damon_ctx *ctx)
{
struct damon_target *t;
struct damon_region *r;
unsigned int max_nr_accesses = 0;
damon_for_each_target(t, ctx) {
damon_for_each_region(r, t) {
__damon_pa_check_access(r);
max_nr_accesses = max(r->nr_accesses, max_nr_accesses);
}
}
return max_nr_accesses;
}
static bool __damos_pa_filter_out(struct damos_filter *filter,
struct folio *folio)
{
bool matched = false;
struct mem_cgroup *memcg;
switch (filter->type) {
case DAMOS_FILTER_TYPE_ANON:
matched = folio_test_anon(folio);
break;
case DAMOS_FILTER_TYPE_MEMCG:
rcu_read_lock();
memcg = folio_memcg_check(folio);
if (!memcg)
matched = false;
else
matched = filter->memcg_id == mem_cgroup_id(memcg);
rcu_read_unlock();
break;
default:
break;
}
return matched == filter->matching;
}
/*
* damos_pa_filter_out - Return true if the page should be filtered out.
*/
static bool damos_pa_filter_out(struct damos *scheme, struct folio *folio)
{
struct damos_filter *filter;
damos_for_each_filter(filter, scheme) {
if (__damos_pa_filter_out(filter, folio))
return true;
}
return false;
}
static unsigned long damon_pa_pageout(struct damon_region *r, struct damos *s)
{
unsigned long addr, applied;
LIST_HEAD(folio_list);
for (addr = r->ar.start; addr < r->ar.end; addr += PAGE_SIZE) {
struct folio *folio = damon_get_folio(PHYS_PFN(addr));
if (!folio)
continue;
if (damos_pa_filter_out(s, folio))
goto put_folio;
folio_clear_referenced(folio);
folio_test_clear_young(folio);
if (!folio_isolate_lru(folio))
goto put_folio;
if (folio_test_unevictable(folio))
folio_putback_lru(folio);
else
list_add(&folio->lru, &folio_list);
put_folio:
folio_put(folio);
}
applied = reclaim_pages(&folio_list);
cond_resched();
return applied * PAGE_SIZE;
}
static inline unsigned long damon_pa_mark_accessed_or_deactivate(
struct damon_region *r, struct damos *s, bool mark_accessed)
{
unsigned long addr, applied = 0;
for (addr = r->ar.start; addr < r->ar.end; addr += PAGE_SIZE) {
struct folio *folio = damon_get_folio(PHYS_PFN(addr));
if (!folio)
continue;
if (damos_pa_filter_out(s, folio))
goto put_folio;
if (mark_accessed)
folio_mark_accessed(folio);
else
folio_deactivate(folio);
applied += folio_nr_pages(folio);
put_folio:
folio_put(folio);
}
return applied * PAGE_SIZE;
}
static unsigned long damon_pa_mark_accessed(struct damon_region *r,
struct damos *s)
{
return damon_pa_mark_accessed_or_deactivate(r, s, true);
}
static unsigned long damon_pa_deactivate_pages(struct damon_region *r,
struct damos *s)
{
return damon_pa_mark_accessed_or_deactivate(r, s, false);
}
static unsigned long damon_pa_apply_scheme(struct damon_ctx *ctx,
struct damon_target *t, struct damon_region *r,
struct damos *scheme)
{
switch (scheme->action) {
case DAMOS_PAGEOUT:
return damon_pa_pageout(r, scheme);
case DAMOS_LRU_PRIO:
return damon_pa_mark_accessed(r, scheme);
case DAMOS_LRU_DEPRIO:
return damon_pa_deactivate_pages(r, scheme);
case DAMOS_STAT:
break;
default:
/* DAMOS actions that not yet supported by 'paddr'. */
break;
}
return 0;
}
static int damon_pa_scheme_score(struct damon_ctx *context,
struct damon_target *t, struct damon_region *r,
struct damos *scheme)
{
switch (scheme->action) {
case DAMOS_PAGEOUT:
return damon_cold_score(context, r, scheme);
case DAMOS_LRU_PRIO:
return damon_hot_score(context, r, scheme);
case DAMOS_LRU_DEPRIO:
return damon_cold_score(context, r, scheme);
default:
break;
}
return DAMOS_MAX_SCORE;
}
static int __init damon_pa_initcall(void)
{
struct damon_operations ops = {
.id = DAMON_OPS_PADDR,
.init = NULL,
.update = NULL,
.prepare_access_checks = damon_pa_prepare_access_checks,
.check_accesses = damon_pa_check_accesses,
.reset_aggregated = NULL,
.target_valid = NULL,
.cleanup = NULL,
.apply_scheme = damon_pa_apply_scheme,
.get_scheme_score = damon_pa_scheme_score,
};
return damon_register_ops(&ops);
};
subsys_initcall(damon_pa_initcall);
| linux-master | mm/damon/paddr.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Common Primitives for DAMON Sysfs Interface
*
* Author: SeongJae Park <[email protected]>
*/
#include <linux/slab.h>
#include "sysfs-common.h"
DEFINE_MUTEX(damon_sysfs_lock);
/*
* unsigned long range directory
*/
struct damon_sysfs_ul_range *damon_sysfs_ul_range_alloc(
unsigned long min,
unsigned long max)
{
struct damon_sysfs_ul_range *range = kmalloc(sizeof(*range),
GFP_KERNEL);
if (!range)
return NULL;
range->kobj = (struct kobject){};
range->min = min;
range->max = max;
return range;
}
static ssize_t min_show(struct kobject *kobj, struct kobj_attribute *attr,
char *buf)
{
struct damon_sysfs_ul_range *range = container_of(kobj,
struct damon_sysfs_ul_range, kobj);
return sysfs_emit(buf, "%lu\n", range->min);
}
static ssize_t min_store(struct kobject *kobj, struct kobj_attribute *attr,
const char *buf, size_t count)
{
struct damon_sysfs_ul_range *range = container_of(kobj,
struct damon_sysfs_ul_range, kobj);
unsigned long min;
int err;
err = kstrtoul(buf, 0, &min);
if (err)
return err;
range->min = min;
return count;
}
static ssize_t max_show(struct kobject *kobj, struct kobj_attribute *attr,
char *buf)
{
struct damon_sysfs_ul_range *range = container_of(kobj,
struct damon_sysfs_ul_range, kobj);
return sysfs_emit(buf, "%lu\n", range->max);
}
static ssize_t max_store(struct kobject *kobj, struct kobj_attribute *attr,
const char *buf, size_t count)
{
struct damon_sysfs_ul_range *range = container_of(kobj,
struct damon_sysfs_ul_range, kobj);
unsigned long max;
int err;
err = kstrtoul(buf, 0, &max);
if (err)
return err;
range->max = max;
return count;
}
void damon_sysfs_ul_range_release(struct kobject *kobj)
{
kfree(container_of(kobj, struct damon_sysfs_ul_range, kobj));
}
static struct kobj_attribute damon_sysfs_ul_range_min_attr =
__ATTR_RW_MODE(min, 0600);
static struct kobj_attribute damon_sysfs_ul_range_max_attr =
__ATTR_RW_MODE(max, 0600);
static struct attribute *damon_sysfs_ul_range_attrs[] = {
&damon_sysfs_ul_range_min_attr.attr,
&damon_sysfs_ul_range_max_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(damon_sysfs_ul_range);
const struct kobj_type damon_sysfs_ul_range_ktype = {
.release = damon_sysfs_ul_range_release,
.sysfs_ops = &kobj_sysfs_ops,
.default_groups = damon_sysfs_ul_range_groups,
};
| linux-master | mm/damon/sysfs-common.c |
// SPDX-License-Identifier: GPL-2.0
/*
* DAMON Primitives for Virtual Address Spaces
*
* Author: SeongJae Park <[email protected]>
*/
#define pr_fmt(fmt) "damon-va: " fmt
#include <asm-generic/mman-common.h>
#include <linux/highmem.h>
#include <linux/hugetlb.h>
#include <linux/mmu_notifier.h>
#include <linux/page_idle.h>
#include <linux/pagewalk.h>
#include <linux/sched/mm.h>
#include "ops-common.h"
#ifdef CONFIG_DAMON_VADDR_KUNIT_TEST
#undef DAMON_MIN_REGION
#define DAMON_MIN_REGION 1
#endif
/*
* 't->pid' should be the pointer to the relevant 'struct pid' having reference
* count. Caller must put the returned task, unless it is NULL.
*/
static inline struct task_struct *damon_get_task_struct(struct damon_target *t)
{
return get_pid_task(t->pid, PIDTYPE_PID);
}
/*
* Get the mm_struct of the given target
*
* Caller _must_ put the mm_struct after use, unless it is NULL.
*
* Returns the mm_struct of the target on success, NULL on failure
*/
static struct mm_struct *damon_get_mm(struct damon_target *t)
{
struct task_struct *task;
struct mm_struct *mm;
task = damon_get_task_struct(t);
if (!task)
return NULL;
mm = get_task_mm(task);
put_task_struct(task);
return mm;
}
/*
* Functions for the initial monitoring target regions construction
*/
/*
* Size-evenly split a region into 'nr_pieces' small regions
*
* Returns 0 on success, or negative error code otherwise.
*/
static int damon_va_evenly_split_region(struct damon_target *t,
struct damon_region *r, unsigned int nr_pieces)
{
unsigned long sz_orig, sz_piece, orig_end;
struct damon_region *n = NULL, *next;
unsigned long start;
if (!r || !nr_pieces)
return -EINVAL;
orig_end = r->ar.end;
sz_orig = damon_sz_region(r);
sz_piece = ALIGN_DOWN(sz_orig / nr_pieces, DAMON_MIN_REGION);
if (!sz_piece)
return -EINVAL;
r->ar.end = r->ar.start + sz_piece;
next = damon_next_region(r);
for (start = r->ar.end; start + sz_piece <= orig_end;
start += sz_piece) {
n = damon_new_region(start, start + sz_piece);
if (!n)
return -ENOMEM;
damon_insert_region(n, r, next, t);
r = n;
}
/* complement last region for possible rounding error */
if (n)
n->ar.end = orig_end;
return 0;
}
static unsigned long sz_range(struct damon_addr_range *r)
{
return r->end - r->start;
}
/*
* Find three regions separated by two biggest unmapped regions
*
* vma the head vma of the target address space
* regions an array of three address ranges that results will be saved
*
* This function receives an address space and finds three regions in it which
* separated by the two biggest unmapped regions in the space. Please refer to
* below comments of '__damon_va_init_regions()' function to know why this is
* necessary.
*
* Returns 0 if success, or negative error code otherwise.
*/
static int __damon_va_three_regions(struct mm_struct *mm,
struct damon_addr_range regions[3])
{
struct damon_addr_range first_gap = {0}, second_gap = {0};
VMA_ITERATOR(vmi, mm, 0);
struct vm_area_struct *vma, *prev = NULL;
unsigned long start;
/*
* Find the two biggest gaps so that first_gap > second_gap > others.
* If this is too slow, it can be optimised to examine the maple
* tree gaps.
*/
for_each_vma(vmi, vma) {
unsigned long gap;
if (!prev) {
start = vma->vm_start;
goto next;
}
gap = vma->vm_start - prev->vm_end;
if (gap > sz_range(&first_gap)) {
second_gap = first_gap;
first_gap.start = prev->vm_end;
first_gap.end = vma->vm_start;
} else if (gap > sz_range(&second_gap)) {
second_gap.start = prev->vm_end;
second_gap.end = vma->vm_start;
}
next:
prev = vma;
}
if (!sz_range(&second_gap) || !sz_range(&first_gap))
return -EINVAL;
/* Sort the two biggest gaps by address */
if (first_gap.start > second_gap.start)
swap(first_gap, second_gap);
/* Store the result */
regions[0].start = ALIGN(start, DAMON_MIN_REGION);
regions[0].end = ALIGN(first_gap.start, DAMON_MIN_REGION);
regions[1].start = ALIGN(first_gap.end, DAMON_MIN_REGION);
regions[1].end = ALIGN(second_gap.start, DAMON_MIN_REGION);
regions[2].start = ALIGN(second_gap.end, DAMON_MIN_REGION);
regions[2].end = ALIGN(prev->vm_end, DAMON_MIN_REGION);
return 0;
}
/*
* Get the three regions in the given target (task)
*
* Returns 0 on success, negative error code otherwise.
*/
static int damon_va_three_regions(struct damon_target *t,
struct damon_addr_range regions[3])
{
struct mm_struct *mm;
int rc;
mm = damon_get_mm(t);
if (!mm)
return -EINVAL;
mmap_read_lock(mm);
rc = __damon_va_three_regions(mm, regions);
mmap_read_unlock(mm);
mmput(mm);
return rc;
}
/*
* Initialize the monitoring target regions for the given target (task)
*
* t the given target
*
* Because only a number of small portions of the entire address space
* is actually mapped to the memory and accessed, monitoring the unmapped
* regions is wasteful. That said, because we can deal with small noises,
* tracking every mapping is not strictly required but could even incur a high
* overhead if the mapping frequently changes or the number of mappings is
* high. The adaptive regions adjustment mechanism will further help to deal
* with the noise by simply identifying the unmapped areas as a region that
* has no access. Moreover, applying the real mappings that would have many
* unmapped areas inside will make the adaptive mechanism quite complex. That
* said, too huge unmapped areas inside the monitoring target should be removed
* to not take the time for the adaptive mechanism.
*
* For the reason, we convert the complex mappings to three distinct regions
* that cover every mapped area of the address space. Also the two gaps
* between the three regions are the two biggest unmapped areas in the given
* address space. In detail, this function first identifies the start and the
* end of the mappings and the two biggest unmapped areas of the address space.
* Then, it constructs the three regions as below:
*
* [mappings[0]->start, big_two_unmapped_areas[0]->start)
* [big_two_unmapped_areas[0]->end, big_two_unmapped_areas[1]->start)
* [big_two_unmapped_areas[1]->end, mappings[nr_mappings - 1]->end)
*
* As usual memory map of processes is as below, the gap between the heap and
* the uppermost mmap()-ed region, and the gap between the lowermost mmap()-ed
* region and the stack will be two biggest unmapped regions. Because these
* gaps are exceptionally huge areas in usual address space, excluding these
* two biggest unmapped regions will be sufficient to make a trade-off.
*
* <heap>
* <BIG UNMAPPED REGION 1>
* <uppermost mmap()-ed region>
* (other mmap()-ed regions and small unmapped regions)
* <lowermost mmap()-ed region>
* <BIG UNMAPPED REGION 2>
* <stack>
*/
static void __damon_va_init_regions(struct damon_ctx *ctx,
struct damon_target *t)
{
struct damon_target *ti;
struct damon_region *r;
struct damon_addr_range regions[3];
unsigned long sz = 0, nr_pieces;
int i, tidx = 0;
if (damon_va_three_regions(t, regions)) {
damon_for_each_target(ti, ctx) {
if (ti == t)
break;
tidx++;
}
pr_debug("Failed to get three regions of %dth target\n", tidx);
return;
}
for (i = 0; i < 3; i++)
sz += regions[i].end - regions[i].start;
if (ctx->attrs.min_nr_regions)
sz /= ctx->attrs.min_nr_regions;
if (sz < DAMON_MIN_REGION)
sz = DAMON_MIN_REGION;
/* Set the initial three regions of the target */
for (i = 0; i < 3; i++) {
r = damon_new_region(regions[i].start, regions[i].end);
if (!r) {
pr_err("%d'th init region creation failed\n", i);
return;
}
damon_add_region(r, t);
nr_pieces = (regions[i].end - regions[i].start) / sz;
damon_va_evenly_split_region(t, r, nr_pieces);
}
}
/* Initialize '->regions_list' of every target (task) */
static void damon_va_init(struct damon_ctx *ctx)
{
struct damon_target *t;
damon_for_each_target(t, ctx) {
/* the user may set the target regions as they want */
if (!damon_nr_regions(t))
__damon_va_init_regions(ctx, t);
}
}
/*
* Update regions for current memory mappings
*/
static void damon_va_update(struct damon_ctx *ctx)
{
struct damon_addr_range three_regions[3];
struct damon_target *t;
damon_for_each_target(t, ctx) {
if (damon_va_three_regions(t, three_regions))
continue;
damon_set_regions(t, three_regions, 3);
}
}
static int damon_mkold_pmd_entry(pmd_t *pmd, unsigned long addr,
unsigned long next, struct mm_walk *walk)
{
pte_t *pte;
pmd_t pmde;
spinlock_t *ptl;
if (pmd_trans_huge(pmdp_get(pmd))) {
ptl = pmd_lock(walk->mm, pmd);
pmde = pmdp_get(pmd);
if (!pmd_present(pmde)) {
spin_unlock(ptl);
return 0;
}
if (pmd_trans_huge(pmde)) {
damon_pmdp_mkold(pmd, walk->vma, addr);
spin_unlock(ptl);
return 0;
}
spin_unlock(ptl);
}
pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
if (!pte) {
walk->action = ACTION_AGAIN;
return 0;
}
if (!pte_present(ptep_get(pte)))
goto out;
damon_ptep_mkold(pte, walk->vma, addr);
out:
pte_unmap_unlock(pte, ptl);
return 0;
}
#ifdef CONFIG_HUGETLB_PAGE
static void damon_hugetlb_mkold(pte_t *pte, struct mm_struct *mm,
struct vm_area_struct *vma, unsigned long addr)
{
bool referenced = false;
pte_t entry = huge_ptep_get(pte);
struct folio *folio = pfn_folio(pte_pfn(entry));
folio_get(folio);
if (pte_young(entry)) {
referenced = true;
entry = pte_mkold(entry);
set_huge_pte_at(mm, addr, pte, entry);
}
#ifdef CONFIG_MMU_NOTIFIER
if (mmu_notifier_clear_young(mm, addr,
addr + huge_page_size(hstate_vma(vma))))
referenced = true;
#endif /* CONFIG_MMU_NOTIFIER */
if (referenced)
folio_set_young(folio);
folio_set_idle(folio);
folio_put(folio);
}
static int damon_mkold_hugetlb_entry(pte_t *pte, unsigned long hmask,
unsigned long addr, unsigned long end,
struct mm_walk *walk)
{
struct hstate *h = hstate_vma(walk->vma);
spinlock_t *ptl;
pte_t entry;
ptl = huge_pte_lock(h, walk->mm, pte);
entry = huge_ptep_get(pte);
if (!pte_present(entry))
goto out;
damon_hugetlb_mkold(pte, walk->mm, walk->vma, addr);
out:
spin_unlock(ptl);
return 0;
}
#else
#define damon_mkold_hugetlb_entry NULL
#endif /* CONFIG_HUGETLB_PAGE */
static const struct mm_walk_ops damon_mkold_ops = {
.pmd_entry = damon_mkold_pmd_entry,
.hugetlb_entry = damon_mkold_hugetlb_entry,
.walk_lock = PGWALK_RDLOCK,
};
static void damon_va_mkold(struct mm_struct *mm, unsigned long addr)
{
mmap_read_lock(mm);
walk_page_range(mm, addr, addr + 1, &damon_mkold_ops, NULL);
mmap_read_unlock(mm);
}
/*
* Functions for the access checking of the regions
*/
static void __damon_va_prepare_access_check(struct mm_struct *mm,
struct damon_region *r)
{
r->sampling_addr = damon_rand(r->ar.start, r->ar.end);
damon_va_mkold(mm, r->sampling_addr);
}
static void damon_va_prepare_access_checks(struct damon_ctx *ctx)
{
struct damon_target *t;
struct mm_struct *mm;
struct damon_region *r;
damon_for_each_target(t, ctx) {
mm = damon_get_mm(t);
if (!mm)
continue;
damon_for_each_region(r, t)
__damon_va_prepare_access_check(mm, r);
mmput(mm);
}
}
struct damon_young_walk_private {
/* size of the folio for the access checked virtual memory address */
unsigned long *folio_sz;
bool young;
};
static int damon_young_pmd_entry(pmd_t *pmd, unsigned long addr,
unsigned long next, struct mm_walk *walk)
{
pte_t *pte;
pte_t ptent;
spinlock_t *ptl;
struct folio *folio;
struct damon_young_walk_private *priv = walk->private;
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
if (pmd_trans_huge(pmdp_get(pmd))) {
pmd_t pmde;
ptl = pmd_lock(walk->mm, pmd);
pmde = pmdp_get(pmd);
if (!pmd_present(pmde)) {
spin_unlock(ptl);
return 0;
}
if (!pmd_trans_huge(pmde)) {
spin_unlock(ptl);
goto regular_page;
}
folio = damon_get_folio(pmd_pfn(pmde));
if (!folio)
goto huge_out;
if (pmd_young(pmde) || !folio_test_idle(folio) ||
mmu_notifier_test_young(walk->mm,
addr))
priv->young = true;
*priv->folio_sz = HPAGE_PMD_SIZE;
folio_put(folio);
huge_out:
spin_unlock(ptl);
return 0;
}
regular_page:
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
if (!pte) {
walk->action = ACTION_AGAIN;
return 0;
}
ptent = ptep_get(pte);
if (!pte_present(ptent))
goto out;
folio = damon_get_folio(pte_pfn(ptent));
if (!folio)
goto out;
if (pte_young(ptent) || !folio_test_idle(folio) ||
mmu_notifier_test_young(walk->mm, addr))
priv->young = true;
*priv->folio_sz = folio_size(folio);
folio_put(folio);
out:
pte_unmap_unlock(pte, ptl);
return 0;
}
#ifdef CONFIG_HUGETLB_PAGE
static int damon_young_hugetlb_entry(pte_t *pte, unsigned long hmask,
unsigned long addr, unsigned long end,
struct mm_walk *walk)
{
struct damon_young_walk_private *priv = walk->private;
struct hstate *h = hstate_vma(walk->vma);
struct folio *folio;
spinlock_t *ptl;
pte_t entry;
ptl = huge_pte_lock(h, walk->mm, pte);
entry = huge_ptep_get(pte);
if (!pte_present(entry))
goto out;
folio = pfn_folio(pte_pfn(entry));
folio_get(folio);
if (pte_young(entry) || !folio_test_idle(folio) ||
mmu_notifier_test_young(walk->mm, addr))
priv->young = true;
*priv->folio_sz = huge_page_size(h);
folio_put(folio);
out:
spin_unlock(ptl);
return 0;
}
#else
#define damon_young_hugetlb_entry NULL
#endif /* CONFIG_HUGETLB_PAGE */
static const struct mm_walk_ops damon_young_ops = {
.pmd_entry = damon_young_pmd_entry,
.hugetlb_entry = damon_young_hugetlb_entry,
.walk_lock = PGWALK_RDLOCK,
};
static bool damon_va_young(struct mm_struct *mm, unsigned long addr,
unsigned long *folio_sz)
{
struct damon_young_walk_private arg = {
.folio_sz = folio_sz,
.young = false,
};
mmap_read_lock(mm);
walk_page_range(mm, addr, addr + 1, &damon_young_ops, &arg);
mmap_read_unlock(mm);
return arg.young;
}
/*
* Check whether the region was accessed after the last preparation
*
* mm 'mm_struct' for the given virtual address space
* r the region to be checked
*/
static void __damon_va_check_access(struct mm_struct *mm,
struct damon_region *r, bool same_target)
{
static unsigned long last_addr;
static unsigned long last_folio_sz = PAGE_SIZE;
static bool last_accessed;
/* If the region is in the last checked page, reuse the result */
if (same_target && (ALIGN_DOWN(last_addr, last_folio_sz) ==
ALIGN_DOWN(r->sampling_addr, last_folio_sz))) {
if (last_accessed)
r->nr_accesses++;
return;
}
last_accessed = damon_va_young(mm, r->sampling_addr, &last_folio_sz);
if (last_accessed)
r->nr_accesses++;
last_addr = r->sampling_addr;
}
static unsigned int damon_va_check_accesses(struct damon_ctx *ctx)
{
struct damon_target *t;
struct mm_struct *mm;
struct damon_region *r;
unsigned int max_nr_accesses = 0;
bool same_target;
damon_for_each_target(t, ctx) {
mm = damon_get_mm(t);
if (!mm)
continue;
same_target = false;
damon_for_each_region(r, t) {
__damon_va_check_access(mm, r, same_target);
max_nr_accesses = max(r->nr_accesses, max_nr_accesses);
same_target = true;
}
mmput(mm);
}
return max_nr_accesses;
}
/*
* Functions for the target validity check and cleanup
*/
static bool damon_va_target_valid(struct damon_target *t)
{
struct task_struct *task;
task = damon_get_task_struct(t);
if (task) {
put_task_struct(task);
return true;
}
return false;
}
#ifndef CONFIG_ADVISE_SYSCALLS
static unsigned long damos_madvise(struct damon_target *target,
struct damon_region *r, int behavior)
{
return 0;
}
#else
static unsigned long damos_madvise(struct damon_target *target,
struct damon_region *r, int behavior)
{
struct mm_struct *mm;
unsigned long start = PAGE_ALIGN(r->ar.start);
unsigned long len = PAGE_ALIGN(damon_sz_region(r));
unsigned long applied;
mm = damon_get_mm(target);
if (!mm)
return 0;
applied = do_madvise(mm, start, len, behavior) ? 0 : len;
mmput(mm);
return applied;
}
#endif /* CONFIG_ADVISE_SYSCALLS */
static unsigned long damon_va_apply_scheme(struct damon_ctx *ctx,
struct damon_target *t, struct damon_region *r,
struct damos *scheme)
{
int madv_action;
switch (scheme->action) {
case DAMOS_WILLNEED:
madv_action = MADV_WILLNEED;
break;
case DAMOS_COLD:
madv_action = MADV_COLD;
break;
case DAMOS_PAGEOUT:
madv_action = MADV_PAGEOUT;
break;
case DAMOS_HUGEPAGE:
madv_action = MADV_HUGEPAGE;
break;
case DAMOS_NOHUGEPAGE:
madv_action = MADV_NOHUGEPAGE;
break;
case DAMOS_STAT:
return 0;
default:
/*
* DAMOS actions that are not yet supported by 'vaddr'.
*/
return 0;
}
return damos_madvise(t, r, madv_action);
}
static int damon_va_scheme_score(struct damon_ctx *context,
struct damon_target *t, struct damon_region *r,
struct damos *scheme)
{
switch (scheme->action) {
case DAMOS_PAGEOUT:
return damon_cold_score(context, r, scheme);
default:
break;
}
return DAMOS_MAX_SCORE;
}
static int __init damon_va_initcall(void)
{
struct damon_operations ops = {
.id = DAMON_OPS_VADDR,
.init = damon_va_init,
.update = damon_va_update,
.prepare_access_checks = damon_va_prepare_access_checks,
.check_accesses = damon_va_check_accesses,
.reset_aggregated = NULL,
.target_valid = damon_va_target_valid,
.cleanup = NULL,
.apply_scheme = damon_va_apply_scheme,
.get_scheme_score = damon_va_scheme_score,
};
/* ops for fixed virtual address ranges */
struct damon_operations ops_fvaddr = ops;
int err;
/* Don't set the monitoring target regions for the entire mapping */
ops_fvaddr.id = DAMON_OPS_FVADDR;
ops_fvaddr.init = NULL;
ops_fvaddr.update = NULL;
err = damon_register_ops(&ops);
if (err)
return err;
return damon_register_ops(&ops_fvaddr);
};
subsys_initcall(damon_va_initcall);
#include "vaddr-test.h"
| linux-master | mm/damon/vaddr.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Data Access Monitor
*
* Author: SeongJae Park <[email protected]>
*/
#define pr_fmt(fmt) "damon: " fmt
#include <linux/damon.h>
#include <linux/delay.h>
#include <linux/kthread.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/string.h>
#define CREATE_TRACE_POINTS
#include <trace/events/damon.h>
#ifdef CONFIG_DAMON_KUNIT_TEST
#undef DAMON_MIN_REGION
#define DAMON_MIN_REGION 1
#endif
static DEFINE_MUTEX(damon_lock);
static int nr_running_ctxs;
static bool running_exclusive_ctxs;
static DEFINE_MUTEX(damon_ops_lock);
static struct damon_operations damon_registered_ops[NR_DAMON_OPS];
static struct kmem_cache *damon_region_cache __ro_after_init;
/* Should be called under damon_ops_lock with id smaller than NR_DAMON_OPS */
static bool __damon_is_registered_ops(enum damon_ops_id id)
{
struct damon_operations empty_ops = {};
if (!memcmp(&empty_ops, &damon_registered_ops[id], sizeof(empty_ops)))
return false;
return true;
}
/**
* damon_is_registered_ops() - Check if a given damon_operations is registered.
* @id: Id of the damon_operations to check if registered.
*
* Return: true if the ops is set, false otherwise.
*/
bool damon_is_registered_ops(enum damon_ops_id id)
{
bool registered;
if (id >= NR_DAMON_OPS)
return false;
mutex_lock(&damon_ops_lock);
registered = __damon_is_registered_ops(id);
mutex_unlock(&damon_ops_lock);
return registered;
}
/**
* damon_register_ops() - Register a monitoring operations set to DAMON.
* @ops: monitoring operations set to register.
*
* This function registers a monitoring operations set of valid &struct
* damon_operations->id so that others can find and use them later.
*
* Return: 0 on success, negative error code otherwise.
*/
int damon_register_ops(struct damon_operations *ops)
{
int err = 0;
if (ops->id >= NR_DAMON_OPS)
return -EINVAL;
mutex_lock(&damon_ops_lock);
/* Fail for already registered ops */
if (__damon_is_registered_ops(ops->id)) {
err = -EINVAL;
goto out;
}
damon_registered_ops[ops->id] = *ops;
out:
mutex_unlock(&damon_ops_lock);
return err;
}
/**
* damon_select_ops() - Select a monitoring operations to use with the context.
* @ctx: monitoring context to use the operations.
* @id: id of the registered monitoring operations to select.
*
* This function finds registered monitoring operations set of @id and make
* @ctx to use it.
*
* Return: 0 on success, negative error code otherwise.
*/
int damon_select_ops(struct damon_ctx *ctx, enum damon_ops_id id)
{
int err = 0;
if (id >= NR_DAMON_OPS)
return -EINVAL;
mutex_lock(&damon_ops_lock);
if (!__damon_is_registered_ops(id))
err = -EINVAL;
else
ctx->ops = damon_registered_ops[id];
mutex_unlock(&damon_ops_lock);
return err;
}
/*
* Construct a damon_region struct
*
* Returns the pointer to the new struct if success, or NULL otherwise
*/
struct damon_region *damon_new_region(unsigned long start, unsigned long end)
{
struct damon_region *region;
region = kmem_cache_alloc(damon_region_cache, GFP_KERNEL);
if (!region)
return NULL;
region->ar.start = start;
region->ar.end = end;
region->nr_accesses = 0;
INIT_LIST_HEAD(®ion->list);
region->age = 0;
region->last_nr_accesses = 0;
return region;
}
void damon_add_region(struct damon_region *r, struct damon_target *t)
{
list_add_tail(&r->list, &t->regions_list);
t->nr_regions++;
}
static void damon_del_region(struct damon_region *r, struct damon_target *t)
{
list_del(&r->list);
t->nr_regions--;
}
static void damon_free_region(struct damon_region *r)
{
kmem_cache_free(damon_region_cache, r);
}
void damon_destroy_region(struct damon_region *r, struct damon_target *t)
{
damon_del_region(r, t);
damon_free_region(r);
}
/*
* Check whether a region is intersecting an address range
*
* Returns true if it is.
*/
static bool damon_intersect(struct damon_region *r,
struct damon_addr_range *re)
{
return !(r->ar.end <= re->start || re->end <= r->ar.start);
}
/*
* Fill holes in regions with new regions.
*/
static int damon_fill_regions_holes(struct damon_region *first,
struct damon_region *last, struct damon_target *t)
{
struct damon_region *r = first;
damon_for_each_region_from(r, t) {
struct damon_region *next, *newr;
if (r == last)
break;
next = damon_next_region(r);
if (r->ar.end != next->ar.start) {
newr = damon_new_region(r->ar.end, next->ar.start);
if (!newr)
return -ENOMEM;
damon_insert_region(newr, r, next, t);
}
}
return 0;
}
/*
* damon_set_regions() - Set regions of a target for given address ranges.
* @t: the given target.
* @ranges: array of new monitoring target ranges.
* @nr_ranges: length of @ranges.
*
* This function adds new regions to, or modify existing regions of a
* monitoring target to fit in specific ranges.
*
* Return: 0 if success, or negative error code otherwise.
*/
int damon_set_regions(struct damon_target *t, struct damon_addr_range *ranges,
unsigned int nr_ranges)
{
struct damon_region *r, *next;
unsigned int i;
int err;
/* Remove regions which are not in the new ranges */
damon_for_each_region_safe(r, next, t) {
for (i = 0; i < nr_ranges; i++) {
if (damon_intersect(r, &ranges[i]))
break;
}
if (i == nr_ranges)
damon_destroy_region(r, t);
}
r = damon_first_region(t);
/* Add new regions or resize existing regions to fit in the ranges */
for (i = 0; i < nr_ranges; i++) {
struct damon_region *first = NULL, *last, *newr;
struct damon_addr_range *range;
range = &ranges[i];
/* Get the first/last regions intersecting with the range */
damon_for_each_region_from(r, t) {
if (damon_intersect(r, range)) {
if (!first)
first = r;
last = r;
}
if (r->ar.start >= range->end)
break;
}
if (!first) {
/* no region intersects with this range */
newr = damon_new_region(
ALIGN_DOWN(range->start,
DAMON_MIN_REGION),
ALIGN(range->end, DAMON_MIN_REGION));
if (!newr)
return -ENOMEM;
damon_insert_region(newr, damon_prev_region(r), r, t);
} else {
/* resize intersecting regions to fit in this range */
first->ar.start = ALIGN_DOWN(range->start,
DAMON_MIN_REGION);
last->ar.end = ALIGN(range->end, DAMON_MIN_REGION);
/* fill possible holes in the range */
err = damon_fill_regions_holes(first, last, t);
if (err)
return err;
}
}
return 0;
}
struct damos_filter *damos_new_filter(enum damos_filter_type type,
bool matching)
{
struct damos_filter *filter;
filter = kmalloc(sizeof(*filter), GFP_KERNEL);
if (!filter)
return NULL;
filter->type = type;
filter->matching = matching;
INIT_LIST_HEAD(&filter->list);
return filter;
}
void damos_add_filter(struct damos *s, struct damos_filter *f)
{
list_add_tail(&f->list, &s->filters);
}
static void damos_del_filter(struct damos_filter *f)
{
list_del(&f->list);
}
static void damos_free_filter(struct damos_filter *f)
{
kfree(f);
}
void damos_destroy_filter(struct damos_filter *f)
{
damos_del_filter(f);
damos_free_filter(f);
}
/* initialize private fields of damos_quota and return the pointer */
static struct damos_quota *damos_quota_init_priv(struct damos_quota *quota)
{
quota->total_charged_sz = 0;
quota->total_charged_ns = 0;
quota->esz = 0;
quota->charged_sz = 0;
quota->charged_from = 0;
quota->charge_target_from = NULL;
quota->charge_addr_from = 0;
return quota;
}
struct damos *damon_new_scheme(struct damos_access_pattern *pattern,
enum damos_action action, struct damos_quota *quota,
struct damos_watermarks *wmarks)
{
struct damos *scheme;
scheme = kmalloc(sizeof(*scheme), GFP_KERNEL);
if (!scheme)
return NULL;
scheme->pattern = *pattern;
scheme->action = action;
INIT_LIST_HEAD(&scheme->filters);
scheme->stat = (struct damos_stat){};
INIT_LIST_HEAD(&scheme->list);
scheme->quota = *(damos_quota_init_priv(quota));
scheme->wmarks = *wmarks;
scheme->wmarks.activated = true;
return scheme;
}
void damon_add_scheme(struct damon_ctx *ctx, struct damos *s)
{
list_add_tail(&s->list, &ctx->schemes);
}
static void damon_del_scheme(struct damos *s)
{
list_del(&s->list);
}
static void damon_free_scheme(struct damos *s)
{
kfree(s);
}
void damon_destroy_scheme(struct damos *s)
{
struct damos_filter *f, *next;
damos_for_each_filter_safe(f, next, s)
damos_destroy_filter(f);
damon_del_scheme(s);
damon_free_scheme(s);
}
/*
* Construct a damon_target struct
*
* Returns the pointer to the new struct if success, or NULL otherwise
*/
struct damon_target *damon_new_target(void)
{
struct damon_target *t;
t = kmalloc(sizeof(*t), GFP_KERNEL);
if (!t)
return NULL;
t->pid = NULL;
t->nr_regions = 0;
INIT_LIST_HEAD(&t->regions_list);
INIT_LIST_HEAD(&t->list);
return t;
}
void damon_add_target(struct damon_ctx *ctx, struct damon_target *t)
{
list_add_tail(&t->list, &ctx->adaptive_targets);
}
bool damon_targets_empty(struct damon_ctx *ctx)
{
return list_empty(&ctx->adaptive_targets);
}
static void damon_del_target(struct damon_target *t)
{
list_del(&t->list);
}
void damon_free_target(struct damon_target *t)
{
struct damon_region *r, *next;
damon_for_each_region_safe(r, next, t)
damon_free_region(r);
kfree(t);
}
void damon_destroy_target(struct damon_target *t)
{
damon_del_target(t);
damon_free_target(t);
}
unsigned int damon_nr_regions(struct damon_target *t)
{
return t->nr_regions;
}
struct damon_ctx *damon_new_ctx(void)
{
struct damon_ctx *ctx;
ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
if (!ctx)
return NULL;
ctx->attrs.sample_interval = 5 * 1000;
ctx->attrs.aggr_interval = 100 * 1000;
ctx->attrs.ops_update_interval = 60 * 1000 * 1000;
ktime_get_coarse_ts64(&ctx->last_aggregation);
ctx->last_ops_update = ctx->last_aggregation;
mutex_init(&ctx->kdamond_lock);
ctx->attrs.min_nr_regions = 10;
ctx->attrs.max_nr_regions = 1000;
INIT_LIST_HEAD(&ctx->adaptive_targets);
INIT_LIST_HEAD(&ctx->schemes);
return ctx;
}
static void damon_destroy_targets(struct damon_ctx *ctx)
{
struct damon_target *t, *next_t;
if (ctx->ops.cleanup) {
ctx->ops.cleanup(ctx);
return;
}
damon_for_each_target_safe(t, next_t, ctx)
damon_destroy_target(t);
}
void damon_destroy_ctx(struct damon_ctx *ctx)
{
struct damos *s, *next_s;
damon_destroy_targets(ctx);
damon_for_each_scheme_safe(s, next_s, ctx)
damon_destroy_scheme(s);
kfree(ctx);
}
static unsigned int damon_age_for_new_attrs(unsigned int age,
struct damon_attrs *old_attrs, struct damon_attrs *new_attrs)
{
return age * old_attrs->aggr_interval / new_attrs->aggr_interval;
}
/* convert access ratio in bp (per 10,000) to nr_accesses */
static unsigned int damon_accesses_bp_to_nr_accesses(
unsigned int accesses_bp, struct damon_attrs *attrs)
{
unsigned int max_nr_accesses =
attrs->aggr_interval / attrs->sample_interval;
return accesses_bp * max_nr_accesses / 10000;
}
/* convert nr_accesses to access ratio in bp (per 10,000) */
static unsigned int damon_nr_accesses_to_accesses_bp(
unsigned int nr_accesses, struct damon_attrs *attrs)
{
unsigned int max_nr_accesses =
attrs->aggr_interval / attrs->sample_interval;
return nr_accesses * 10000 / max_nr_accesses;
}
static unsigned int damon_nr_accesses_for_new_attrs(unsigned int nr_accesses,
struct damon_attrs *old_attrs, struct damon_attrs *new_attrs)
{
return damon_accesses_bp_to_nr_accesses(
damon_nr_accesses_to_accesses_bp(
nr_accesses, old_attrs),
new_attrs);
}
static void damon_update_monitoring_result(struct damon_region *r,
struct damon_attrs *old_attrs, struct damon_attrs *new_attrs)
{
r->nr_accesses = damon_nr_accesses_for_new_attrs(r->nr_accesses,
old_attrs, new_attrs);
r->age = damon_age_for_new_attrs(r->age, old_attrs, new_attrs);
}
/*
* region->nr_accesses is the number of sampling intervals in the last
* aggregation interval that access to the region has found, and region->age is
* the number of aggregation intervals that its access pattern has maintained.
* For the reason, the real meaning of the two fields depend on current
* sampling interval and aggregation interval. This function updates
* ->nr_accesses and ->age of given damon_ctx's regions for new damon_attrs.
*/
static void damon_update_monitoring_results(struct damon_ctx *ctx,
struct damon_attrs *new_attrs)
{
struct damon_attrs *old_attrs = &ctx->attrs;
struct damon_target *t;
struct damon_region *r;
/* if any interval is zero, simply forgive conversion */
if (!old_attrs->sample_interval || !old_attrs->aggr_interval ||
!new_attrs->sample_interval ||
!new_attrs->aggr_interval)
return;
damon_for_each_target(t, ctx)
damon_for_each_region(r, t)
damon_update_monitoring_result(
r, old_attrs, new_attrs);
}
/**
* damon_set_attrs() - Set attributes for the monitoring.
* @ctx: monitoring context
* @attrs: monitoring attributes
*
* This function should not be called while the kdamond is running.
* Every time interval is in micro-seconds.
*
* Return: 0 on success, negative error code otherwise.
*/
int damon_set_attrs(struct damon_ctx *ctx, struct damon_attrs *attrs)
{
if (attrs->min_nr_regions < 3)
return -EINVAL;
if (attrs->min_nr_regions > attrs->max_nr_regions)
return -EINVAL;
if (attrs->sample_interval > attrs->aggr_interval)
return -EINVAL;
damon_update_monitoring_results(ctx, attrs);
ctx->attrs = *attrs;
return 0;
}
/**
* damon_set_schemes() - Set data access monitoring based operation schemes.
* @ctx: monitoring context
* @schemes: array of the schemes
* @nr_schemes: number of entries in @schemes
*
* This function should not be called while the kdamond of the context is
* running.
*/
void damon_set_schemes(struct damon_ctx *ctx, struct damos **schemes,
ssize_t nr_schemes)
{
struct damos *s, *next;
ssize_t i;
damon_for_each_scheme_safe(s, next, ctx)
damon_destroy_scheme(s);
for (i = 0; i < nr_schemes; i++)
damon_add_scheme(ctx, schemes[i]);
}
/**
* damon_nr_running_ctxs() - Return number of currently running contexts.
*/
int damon_nr_running_ctxs(void)
{
int nr_ctxs;
mutex_lock(&damon_lock);
nr_ctxs = nr_running_ctxs;
mutex_unlock(&damon_lock);
return nr_ctxs;
}
/* Returns the size upper limit for each monitoring region */
static unsigned long damon_region_sz_limit(struct damon_ctx *ctx)
{
struct damon_target *t;
struct damon_region *r;
unsigned long sz = 0;
damon_for_each_target(t, ctx) {
damon_for_each_region(r, t)
sz += damon_sz_region(r);
}
if (ctx->attrs.min_nr_regions)
sz /= ctx->attrs.min_nr_regions;
if (sz < DAMON_MIN_REGION)
sz = DAMON_MIN_REGION;
return sz;
}
static int kdamond_fn(void *data);
/*
* __damon_start() - Starts monitoring with given context.
* @ctx: monitoring context
*
* This function should be called while damon_lock is hold.
*
* Return: 0 on success, negative error code otherwise.
*/
static int __damon_start(struct damon_ctx *ctx)
{
int err = -EBUSY;
mutex_lock(&ctx->kdamond_lock);
if (!ctx->kdamond) {
err = 0;
ctx->kdamond = kthread_run(kdamond_fn, ctx, "kdamond.%d",
nr_running_ctxs);
if (IS_ERR(ctx->kdamond)) {
err = PTR_ERR(ctx->kdamond);
ctx->kdamond = NULL;
}
}
mutex_unlock(&ctx->kdamond_lock);
return err;
}
/**
* damon_start() - Starts the monitorings for a given group of contexts.
* @ctxs: an array of the pointers for contexts to start monitoring
* @nr_ctxs: size of @ctxs
* @exclusive: exclusiveness of this contexts group
*
* This function starts a group of monitoring threads for a group of monitoring
* contexts. One thread per each context is created and run in parallel. The
* caller should handle synchronization between the threads by itself. If
* @exclusive is true and a group of threads that created by other
* 'damon_start()' call is currently running, this function does nothing but
* returns -EBUSY.
*
* Return: 0 on success, negative error code otherwise.
*/
int damon_start(struct damon_ctx **ctxs, int nr_ctxs, bool exclusive)
{
int i;
int err = 0;
mutex_lock(&damon_lock);
if ((exclusive && nr_running_ctxs) ||
(!exclusive && running_exclusive_ctxs)) {
mutex_unlock(&damon_lock);
return -EBUSY;
}
for (i = 0; i < nr_ctxs; i++) {
err = __damon_start(ctxs[i]);
if (err)
break;
nr_running_ctxs++;
}
if (exclusive && nr_running_ctxs)
running_exclusive_ctxs = true;
mutex_unlock(&damon_lock);
return err;
}
/*
* __damon_stop() - Stops monitoring of a given context.
* @ctx: monitoring context
*
* Return: 0 on success, negative error code otherwise.
*/
static int __damon_stop(struct damon_ctx *ctx)
{
struct task_struct *tsk;
mutex_lock(&ctx->kdamond_lock);
tsk = ctx->kdamond;
if (tsk) {
get_task_struct(tsk);
mutex_unlock(&ctx->kdamond_lock);
kthread_stop(tsk);
put_task_struct(tsk);
return 0;
}
mutex_unlock(&ctx->kdamond_lock);
return -EPERM;
}
/**
* damon_stop() - Stops the monitorings for a given group of contexts.
* @ctxs: an array of the pointers for contexts to stop monitoring
* @nr_ctxs: size of @ctxs
*
* Return: 0 on success, negative error code otherwise.
*/
int damon_stop(struct damon_ctx **ctxs, int nr_ctxs)
{
int i, err = 0;
for (i = 0; i < nr_ctxs; i++) {
/* nr_running_ctxs is decremented in kdamond_fn */
err = __damon_stop(ctxs[i]);
if (err)
break;
}
return err;
}
/*
* damon_check_reset_time_interval() - Check if a time interval is elapsed.
* @baseline: the time to check whether the interval has elapsed since
* @interval: the time interval (microseconds)
*
* See whether the given time interval has passed since the given baseline
* time. If so, it also updates the baseline to current time for next check.
*
* Return: true if the time interval has passed, or false otherwise.
*/
static bool damon_check_reset_time_interval(struct timespec64 *baseline,
unsigned long interval)
{
struct timespec64 now;
ktime_get_coarse_ts64(&now);
if ((timespec64_to_ns(&now) - timespec64_to_ns(baseline)) <
interval * 1000)
return false;
*baseline = now;
return true;
}
/*
* Check whether it is time to flush the aggregated information
*/
static bool kdamond_aggregate_interval_passed(struct damon_ctx *ctx)
{
return damon_check_reset_time_interval(&ctx->last_aggregation,
ctx->attrs.aggr_interval);
}
/*
* Reset the aggregated monitoring results ('nr_accesses' of each region).
*/
static void kdamond_reset_aggregated(struct damon_ctx *c)
{
struct damon_target *t;
unsigned int ti = 0; /* target's index */
damon_for_each_target(t, c) {
struct damon_region *r;
damon_for_each_region(r, t) {
trace_damon_aggregated(t, ti, r, damon_nr_regions(t));
r->last_nr_accesses = r->nr_accesses;
r->nr_accesses = 0;
}
ti++;
}
}
static void damon_split_region_at(struct damon_target *t,
struct damon_region *r, unsigned long sz_r);
static bool __damos_valid_target(struct damon_region *r, struct damos *s)
{
unsigned long sz;
sz = damon_sz_region(r);
return s->pattern.min_sz_region <= sz &&
sz <= s->pattern.max_sz_region &&
s->pattern.min_nr_accesses <= r->nr_accesses &&
r->nr_accesses <= s->pattern.max_nr_accesses &&
s->pattern.min_age_region <= r->age &&
r->age <= s->pattern.max_age_region;
}
static bool damos_valid_target(struct damon_ctx *c, struct damon_target *t,
struct damon_region *r, struct damos *s)
{
bool ret = __damos_valid_target(r, s);
if (!ret || !s->quota.esz || !c->ops.get_scheme_score)
return ret;
return c->ops.get_scheme_score(c, t, r, s) >= s->quota.min_score;
}
/*
* damos_skip_charged_region() - Check if the given region or starting part of
* it is already charged for the DAMOS quota.
* @t: The target of the region.
* @rp: The pointer to the region.
* @s: The scheme to be applied.
*
* If a quota of a scheme has exceeded in a quota charge window, the scheme's
* action would applied to only a part of the target access pattern fulfilling
* regions. To avoid applying the scheme action to only already applied
* regions, DAMON skips applying the scheme action to the regions that charged
* in the previous charge window.
*
* This function checks if a given region should be skipped or not for the
* reason. If only the starting part of the region has previously charged,
* this function splits the region into two so that the second one covers the
* area that not charged in the previous charge widnow and saves the second
* region in *rp and returns false, so that the caller can apply DAMON action
* to the second one.
*
* Return: true if the region should be entirely skipped, false otherwise.
*/
static bool damos_skip_charged_region(struct damon_target *t,
struct damon_region **rp, struct damos *s)
{
struct damon_region *r = *rp;
struct damos_quota *quota = &s->quota;
unsigned long sz_to_skip;
/* Skip previously charged regions */
if (quota->charge_target_from) {
if (t != quota->charge_target_from)
return true;
if (r == damon_last_region(t)) {
quota->charge_target_from = NULL;
quota->charge_addr_from = 0;
return true;
}
if (quota->charge_addr_from &&
r->ar.end <= quota->charge_addr_from)
return true;
if (quota->charge_addr_from && r->ar.start <
quota->charge_addr_from) {
sz_to_skip = ALIGN_DOWN(quota->charge_addr_from -
r->ar.start, DAMON_MIN_REGION);
if (!sz_to_skip) {
if (damon_sz_region(r) <= DAMON_MIN_REGION)
return true;
sz_to_skip = DAMON_MIN_REGION;
}
damon_split_region_at(t, r, sz_to_skip);
r = damon_next_region(r);
*rp = r;
}
quota->charge_target_from = NULL;
quota->charge_addr_from = 0;
}
return false;
}
static void damos_update_stat(struct damos *s,
unsigned long sz_tried, unsigned long sz_applied)
{
s->stat.nr_tried++;
s->stat.sz_tried += sz_tried;
if (sz_applied)
s->stat.nr_applied++;
s->stat.sz_applied += sz_applied;
}
static bool __damos_filter_out(struct damon_ctx *ctx, struct damon_target *t,
struct damon_region *r, struct damos_filter *filter)
{
bool matched = false;
struct damon_target *ti;
int target_idx = 0;
unsigned long start, end;
switch (filter->type) {
case DAMOS_FILTER_TYPE_TARGET:
damon_for_each_target(ti, ctx) {
if (ti == t)
break;
target_idx++;
}
matched = target_idx == filter->target_idx;
break;
case DAMOS_FILTER_TYPE_ADDR:
start = ALIGN_DOWN(filter->addr_range.start, DAMON_MIN_REGION);
end = ALIGN_DOWN(filter->addr_range.end, DAMON_MIN_REGION);
/* inside the range */
if (start <= r->ar.start && r->ar.end <= end) {
matched = true;
break;
}
/* outside of the range */
if (r->ar.end <= start || end <= r->ar.start) {
matched = false;
break;
}
/* start before the range and overlap */
if (r->ar.start < start) {
damon_split_region_at(t, r, start - r->ar.start);
matched = false;
break;
}
/* start inside the range */
damon_split_region_at(t, r, end - r->ar.start);
matched = true;
break;
default:
break;
}
return matched == filter->matching;
}
static bool damos_filter_out(struct damon_ctx *ctx, struct damon_target *t,
struct damon_region *r, struct damos *s)
{
struct damos_filter *filter;
damos_for_each_filter(filter, s) {
if (__damos_filter_out(ctx, t, r, filter))
return true;
}
return false;
}
static void damos_apply_scheme(struct damon_ctx *c, struct damon_target *t,
struct damon_region *r, struct damos *s)
{
struct damos_quota *quota = &s->quota;
unsigned long sz = damon_sz_region(r);
struct timespec64 begin, end;
unsigned long sz_applied = 0;
int err = 0;
if (c->ops.apply_scheme) {
if (quota->esz && quota->charged_sz + sz > quota->esz) {
sz = ALIGN_DOWN(quota->esz - quota->charged_sz,
DAMON_MIN_REGION);
if (!sz)
goto update_stat;
damon_split_region_at(t, r, sz);
}
if (damos_filter_out(c, t, r, s))
return;
ktime_get_coarse_ts64(&begin);
if (c->callback.before_damos_apply)
err = c->callback.before_damos_apply(c, t, r, s);
if (!err)
sz_applied = c->ops.apply_scheme(c, t, r, s);
ktime_get_coarse_ts64(&end);
quota->total_charged_ns += timespec64_to_ns(&end) -
timespec64_to_ns(&begin);
quota->charged_sz += sz;
if (quota->esz && quota->charged_sz >= quota->esz) {
quota->charge_target_from = t;
quota->charge_addr_from = r->ar.end + 1;
}
}
if (s->action != DAMOS_STAT)
r->age = 0;
update_stat:
damos_update_stat(s, sz, sz_applied);
}
static void damon_do_apply_schemes(struct damon_ctx *c,
struct damon_target *t,
struct damon_region *r)
{
struct damos *s;
damon_for_each_scheme(s, c) {
struct damos_quota *quota = &s->quota;
if (!s->wmarks.activated)
continue;
/* Check the quota */
if (quota->esz && quota->charged_sz >= quota->esz)
continue;
if (damos_skip_charged_region(t, &r, s))
continue;
if (!damos_valid_target(c, t, r, s))
continue;
damos_apply_scheme(c, t, r, s);
}
}
/* Shouldn't be called if quota->ms and quota->sz are zero */
static void damos_set_effective_quota(struct damos_quota *quota)
{
unsigned long throughput;
unsigned long esz;
if (!quota->ms) {
quota->esz = quota->sz;
return;
}
if (quota->total_charged_ns)
throughput = quota->total_charged_sz * 1000000 /
quota->total_charged_ns;
else
throughput = PAGE_SIZE * 1024;
esz = throughput * quota->ms;
if (quota->sz && quota->sz < esz)
esz = quota->sz;
quota->esz = esz;
}
static void damos_adjust_quota(struct damon_ctx *c, struct damos *s)
{
struct damos_quota *quota = &s->quota;
struct damon_target *t;
struct damon_region *r;
unsigned long cumulated_sz;
unsigned int score, max_score = 0;
if (!quota->ms && !quota->sz)
return;
/* New charge window starts */
if (time_after_eq(jiffies, quota->charged_from +
msecs_to_jiffies(quota->reset_interval))) {
if (quota->esz && quota->charged_sz >= quota->esz)
s->stat.qt_exceeds++;
quota->total_charged_sz += quota->charged_sz;
quota->charged_from = jiffies;
quota->charged_sz = 0;
damos_set_effective_quota(quota);
}
if (!c->ops.get_scheme_score)
return;
/* Fill up the score histogram */
memset(quota->histogram, 0, sizeof(quota->histogram));
damon_for_each_target(t, c) {
damon_for_each_region(r, t) {
if (!__damos_valid_target(r, s))
continue;
score = c->ops.get_scheme_score(c, t, r, s);
quota->histogram[score] += damon_sz_region(r);
if (score > max_score)
max_score = score;
}
}
/* Set the min score limit */
for (cumulated_sz = 0, score = max_score; ; score--) {
cumulated_sz += quota->histogram[score];
if (cumulated_sz >= quota->esz || !score)
break;
}
quota->min_score = score;
}
static void kdamond_apply_schemes(struct damon_ctx *c)
{
struct damon_target *t;
struct damon_region *r, *next_r;
struct damos *s;
damon_for_each_scheme(s, c) {
if (!s->wmarks.activated)
continue;
damos_adjust_quota(c, s);
}
damon_for_each_target(t, c) {
damon_for_each_region_safe(r, next_r, t)
damon_do_apply_schemes(c, t, r);
}
}
/*
* Merge two adjacent regions into one region
*/
static void damon_merge_two_regions(struct damon_target *t,
struct damon_region *l, struct damon_region *r)
{
unsigned long sz_l = damon_sz_region(l), sz_r = damon_sz_region(r);
l->nr_accesses = (l->nr_accesses * sz_l + r->nr_accesses * sz_r) /
(sz_l + sz_r);
l->age = (l->age * sz_l + r->age * sz_r) / (sz_l + sz_r);
l->ar.end = r->ar.end;
damon_destroy_region(r, t);
}
/*
* Merge adjacent regions having similar access frequencies
*
* t target affected by this merge operation
* thres '->nr_accesses' diff threshold for the merge
* sz_limit size upper limit of each region
*/
static void damon_merge_regions_of(struct damon_target *t, unsigned int thres,
unsigned long sz_limit)
{
struct damon_region *r, *prev = NULL, *next;
damon_for_each_region_safe(r, next, t) {
if (abs(r->nr_accesses - r->last_nr_accesses) > thres)
r->age = 0;
else
r->age++;
if (prev && prev->ar.end == r->ar.start &&
abs(prev->nr_accesses - r->nr_accesses) <= thres &&
damon_sz_region(prev) + damon_sz_region(r) <= sz_limit)
damon_merge_two_regions(t, prev, r);
else
prev = r;
}
}
/*
* Merge adjacent regions having similar access frequencies
*
* threshold '->nr_accesses' diff threshold for the merge
* sz_limit size upper limit of each region
*
* This function merges monitoring target regions which are adjacent and their
* access frequencies are similar. This is for minimizing the monitoring
* overhead under the dynamically changeable access pattern. If a merge was
* unnecessarily made, later 'kdamond_split_regions()' will revert it.
*/
static void kdamond_merge_regions(struct damon_ctx *c, unsigned int threshold,
unsigned long sz_limit)
{
struct damon_target *t;
damon_for_each_target(t, c)
damon_merge_regions_of(t, threshold, sz_limit);
}
/*
* Split a region in two
*
* r the region to be split
* sz_r size of the first sub-region that will be made
*/
static void damon_split_region_at(struct damon_target *t,
struct damon_region *r, unsigned long sz_r)
{
struct damon_region *new;
new = damon_new_region(r->ar.start + sz_r, r->ar.end);
if (!new)
return;
r->ar.end = new->ar.start;
new->age = r->age;
new->last_nr_accesses = r->last_nr_accesses;
damon_insert_region(new, r, damon_next_region(r), t);
}
/* Split every region in the given target into 'nr_subs' regions */
static void damon_split_regions_of(struct damon_target *t, int nr_subs)
{
struct damon_region *r, *next;
unsigned long sz_region, sz_sub = 0;
int i;
damon_for_each_region_safe(r, next, t) {
sz_region = damon_sz_region(r);
for (i = 0; i < nr_subs - 1 &&
sz_region > 2 * DAMON_MIN_REGION; i++) {
/*
* Randomly select size of left sub-region to be at
* least 10 percent and at most 90% of original region
*/
sz_sub = ALIGN_DOWN(damon_rand(1, 10) *
sz_region / 10, DAMON_MIN_REGION);
/* Do not allow blank region */
if (sz_sub == 0 || sz_sub >= sz_region)
continue;
damon_split_region_at(t, r, sz_sub);
sz_region = sz_sub;
}
}
}
/*
* Split every target region into randomly-sized small regions
*
* This function splits every target region into random-sized small regions if
* current total number of the regions is equal or smaller than half of the
* user-specified maximum number of regions. This is for maximizing the
* monitoring accuracy under the dynamically changeable access patterns. If a
* split was unnecessarily made, later 'kdamond_merge_regions()' will revert
* it.
*/
static void kdamond_split_regions(struct damon_ctx *ctx)
{
struct damon_target *t;
unsigned int nr_regions = 0;
static unsigned int last_nr_regions;
int nr_subregions = 2;
damon_for_each_target(t, ctx)
nr_regions += damon_nr_regions(t);
if (nr_regions > ctx->attrs.max_nr_regions / 2)
return;
/* Maybe the middle of the region has different access frequency */
if (last_nr_regions == nr_regions &&
nr_regions < ctx->attrs.max_nr_regions / 3)
nr_subregions = 3;
damon_for_each_target(t, ctx)
damon_split_regions_of(t, nr_subregions);
last_nr_regions = nr_regions;
}
/*
* Check whether it is time to check and apply the operations-related data
* structures.
*
* Returns true if it is.
*/
static bool kdamond_need_update_operations(struct damon_ctx *ctx)
{
return damon_check_reset_time_interval(&ctx->last_ops_update,
ctx->attrs.ops_update_interval);
}
/*
* Check whether current monitoring should be stopped
*
* The monitoring is stopped when either the user requested to stop, or all
* monitoring targets are invalid.
*
* Returns true if need to stop current monitoring.
*/
static bool kdamond_need_stop(struct damon_ctx *ctx)
{
struct damon_target *t;
if (kthread_should_stop())
return true;
if (!ctx->ops.target_valid)
return false;
damon_for_each_target(t, ctx) {
if (ctx->ops.target_valid(t))
return false;
}
return true;
}
static unsigned long damos_wmark_metric_value(enum damos_wmark_metric metric)
{
struct sysinfo i;
switch (metric) {
case DAMOS_WMARK_FREE_MEM_RATE:
si_meminfo(&i);
return i.freeram * 1000 / i.totalram;
default:
break;
}
return -EINVAL;
}
/*
* Returns zero if the scheme is active. Else, returns time to wait for next
* watermark check in micro-seconds.
*/
static unsigned long damos_wmark_wait_us(struct damos *scheme)
{
unsigned long metric;
if (scheme->wmarks.metric == DAMOS_WMARK_NONE)
return 0;
metric = damos_wmark_metric_value(scheme->wmarks.metric);
/* higher than high watermark or lower than low watermark */
if (metric > scheme->wmarks.high || scheme->wmarks.low > metric) {
if (scheme->wmarks.activated)
pr_debug("deactivate a scheme (%d) for %s wmark\n",
scheme->action,
metric > scheme->wmarks.high ?
"high" : "low");
scheme->wmarks.activated = false;
return scheme->wmarks.interval;
}
/* inactive and higher than middle watermark */
if ((scheme->wmarks.high >= metric && metric >= scheme->wmarks.mid) &&
!scheme->wmarks.activated)
return scheme->wmarks.interval;
if (!scheme->wmarks.activated)
pr_debug("activate a scheme (%d)\n", scheme->action);
scheme->wmarks.activated = true;
return 0;
}
static void kdamond_usleep(unsigned long usecs)
{
/* See Documentation/timers/timers-howto.rst for the thresholds */
if (usecs > 20 * USEC_PER_MSEC)
schedule_timeout_idle(usecs_to_jiffies(usecs));
else
usleep_idle_range(usecs, usecs + 1);
}
/* Returns negative error code if it's not activated but should return */
static int kdamond_wait_activation(struct damon_ctx *ctx)
{
struct damos *s;
unsigned long wait_time;
unsigned long min_wait_time = 0;
bool init_wait_time = false;
while (!kdamond_need_stop(ctx)) {
damon_for_each_scheme(s, ctx) {
wait_time = damos_wmark_wait_us(s);
if (!init_wait_time || wait_time < min_wait_time) {
init_wait_time = true;
min_wait_time = wait_time;
}
}
if (!min_wait_time)
return 0;
kdamond_usleep(min_wait_time);
if (ctx->callback.after_wmarks_check &&
ctx->callback.after_wmarks_check(ctx))
break;
}
return -EBUSY;
}
/*
* The monitoring daemon that runs as a kernel thread
*/
static int kdamond_fn(void *data)
{
struct damon_ctx *ctx = data;
struct damon_target *t;
struct damon_region *r, *next;
unsigned int max_nr_accesses = 0;
unsigned long sz_limit = 0;
pr_debug("kdamond (%d) starts\n", current->pid);
if (ctx->ops.init)
ctx->ops.init(ctx);
if (ctx->callback.before_start && ctx->callback.before_start(ctx))
goto done;
sz_limit = damon_region_sz_limit(ctx);
while (!kdamond_need_stop(ctx)) {
if (kdamond_wait_activation(ctx))
break;
if (ctx->ops.prepare_access_checks)
ctx->ops.prepare_access_checks(ctx);
if (ctx->callback.after_sampling &&
ctx->callback.after_sampling(ctx))
break;
kdamond_usleep(ctx->attrs.sample_interval);
if (ctx->ops.check_accesses)
max_nr_accesses = ctx->ops.check_accesses(ctx);
if (kdamond_aggregate_interval_passed(ctx)) {
kdamond_merge_regions(ctx,
max_nr_accesses / 10,
sz_limit);
if (ctx->callback.after_aggregation &&
ctx->callback.after_aggregation(ctx))
break;
if (!list_empty(&ctx->schemes))
kdamond_apply_schemes(ctx);
kdamond_reset_aggregated(ctx);
kdamond_split_regions(ctx);
if (ctx->ops.reset_aggregated)
ctx->ops.reset_aggregated(ctx);
}
if (kdamond_need_update_operations(ctx)) {
if (ctx->ops.update)
ctx->ops.update(ctx);
sz_limit = damon_region_sz_limit(ctx);
}
}
done:
damon_for_each_target(t, ctx) {
damon_for_each_region_safe(r, next, t)
damon_destroy_region(r, t);
}
if (ctx->callback.before_terminate)
ctx->callback.before_terminate(ctx);
if (ctx->ops.cleanup)
ctx->ops.cleanup(ctx);
pr_debug("kdamond (%d) finishes\n", current->pid);
mutex_lock(&ctx->kdamond_lock);
ctx->kdamond = NULL;
mutex_unlock(&ctx->kdamond_lock);
mutex_lock(&damon_lock);
nr_running_ctxs--;
if (!nr_running_ctxs && running_exclusive_ctxs)
running_exclusive_ctxs = false;
mutex_unlock(&damon_lock);
return 0;
}
/*
* struct damon_system_ram_region - System RAM resource address region of
* [@start, @end).
* @start: Start address of the region (inclusive).
* @end: End address of the region (exclusive).
*/
struct damon_system_ram_region {
unsigned long start;
unsigned long end;
};
static int walk_system_ram(struct resource *res, void *arg)
{
struct damon_system_ram_region *a = arg;
if (a->end - a->start < resource_size(res)) {
a->start = res->start;
a->end = res->end;
}
return 0;
}
/*
* Find biggest 'System RAM' resource and store its start and end address in
* @start and @end, respectively. If no System RAM is found, returns false.
*/
static bool damon_find_biggest_system_ram(unsigned long *start,
unsigned long *end)
{
struct damon_system_ram_region arg = {};
walk_system_ram_res(0, ULONG_MAX, &arg, walk_system_ram);
if (arg.end <= arg.start)
return false;
*start = arg.start;
*end = arg.end;
return true;
}
/**
* damon_set_region_biggest_system_ram_default() - Set the region of the given
* monitoring target as requested, or biggest 'System RAM'.
* @t: The monitoring target to set the region.
* @start: The pointer to the start address of the region.
* @end: The pointer to the end address of the region.
*
* This function sets the region of @t as requested by @start and @end. If the
* values of @start and @end are zero, however, this function finds the biggest
* 'System RAM' resource and sets the region to cover the resource. In the
* latter case, this function saves the start and end addresses of the resource
* in @start and @end, respectively.
*
* Return: 0 on success, negative error code otherwise.
*/
int damon_set_region_biggest_system_ram_default(struct damon_target *t,
unsigned long *start, unsigned long *end)
{
struct damon_addr_range addr_range;
if (*start > *end)
return -EINVAL;
if (!*start && !*end &&
!damon_find_biggest_system_ram(start, end))
return -EINVAL;
addr_range.start = *start;
addr_range.end = *end;
return damon_set_regions(t, &addr_range, 1);
}
static int __init damon_init(void)
{
damon_region_cache = KMEM_CACHE(damon_region, 0);
if (unlikely(!damon_region_cache)) {
pr_err("creating damon_region_cache fails\n");
return -ENOMEM;
}
return 0;
}
subsys_initcall(damon_init);
#include "core-test.h"
| linux-master | mm/damon/core.c |
// SPDX-License-Identifier: GPL-2.0
/*
* DAMON-based page reclamation
*
* Author: SeongJae Park <[email protected]>
*/
#define pr_fmt(fmt) "damon-reclaim: " fmt
#include <linux/damon.h>
#include <linux/kstrtox.h>
#include <linux/module.h>
#include "modules-common.h"
#ifdef MODULE_PARAM_PREFIX
#undef MODULE_PARAM_PREFIX
#endif
#define MODULE_PARAM_PREFIX "damon_reclaim."
/*
* Enable or disable DAMON_RECLAIM.
*
* You can enable DAMON_RCLAIM by setting the value of this parameter as ``Y``.
* Setting it as ``N`` disables DAMON_RECLAIM. Note that DAMON_RECLAIM could
* do no real monitoring and reclamation due to the watermarks-based activation
* condition. Refer to below descriptions for the watermarks parameter for
* this.
*/
static bool enabled __read_mostly;
/*
* Make DAMON_RECLAIM reads the input parameters again, except ``enabled``.
*
* Input parameters that updated while DAMON_RECLAIM is running are not applied
* by default. Once this parameter is set as ``Y``, DAMON_RECLAIM reads values
* of parametrs except ``enabled`` again. Once the re-reading is done, this
* parameter is set as ``N``. If invalid parameters are found while the
* re-reading, DAMON_RECLAIM will be disabled.
*/
static bool commit_inputs __read_mostly;
module_param(commit_inputs, bool, 0600);
/*
* Time threshold for cold memory regions identification in microseconds.
*
* If a memory region is not accessed for this or longer time, DAMON_RECLAIM
* identifies the region as cold, and reclaims. 120 seconds by default.
*/
static unsigned long min_age __read_mostly = 120000000;
module_param(min_age, ulong, 0600);
static struct damos_quota damon_reclaim_quota = {
/* use up to 10 ms time, reclaim up to 128 MiB per 1 sec by default */
.ms = 10,
.sz = 128 * 1024 * 1024,
.reset_interval = 1000,
/* Within the quota, page out older regions first. */
.weight_sz = 0,
.weight_nr_accesses = 0,
.weight_age = 1
};
DEFINE_DAMON_MODULES_DAMOS_QUOTAS(damon_reclaim_quota);
static struct damos_watermarks damon_reclaim_wmarks = {
.metric = DAMOS_WMARK_FREE_MEM_RATE,
.interval = 5000000, /* 5 seconds */
.high = 500, /* 50 percent */
.mid = 400, /* 40 percent */
.low = 200, /* 20 percent */
};
DEFINE_DAMON_MODULES_WMARKS_PARAMS(damon_reclaim_wmarks);
static struct damon_attrs damon_reclaim_mon_attrs = {
.sample_interval = 5000, /* 5 ms */
.aggr_interval = 100000, /* 100 ms */
.ops_update_interval = 0,
.min_nr_regions = 10,
.max_nr_regions = 1000,
};
DEFINE_DAMON_MODULES_MON_ATTRS_PARAMS(damon_reclaim_mon_attrs);
/*
* Start of the target memory region in physical address.
*
* The start physical address of memory region that DAMON_RECLAIM will do work
* against. By default, biggest System RAM is used as the region.
*/
static unsigned long monitor_region_start __read_mostly;
module_param(monitor_region_start, ulong, 0600);
/*
* End of the target memory region in physical address.
*
* The end physical address of memory region that DAMON_RECLAIM will do work
* against. By default, biggest System RAM is used as the region.
*/
static unsigned long monitor_region_end __read_mostly;
module_param(monitor_region_end, ulong, 0600);
/*
* Skip anonymous pages reclamation.
*
* If this parameter is set as ``Y``, DAMON_RECLAIM does not reclaim anonymous
* pages. By default, ``N``.
*/
static bool skip_anon __read_mostly;
module_param(skip_anon, bool, 0600);
/*
* PID of the DAMON thread
*
* If DAMON_RECLAIM is enabled, this becomes the PID of the worker thread.
* Else, -1.
*/
static int kdamond_pid __read_mostly = -1;
module_param(kdamond_pid, int, 0400);
static struct damos_stat damon_reclaim_stat;
DEFINE_DAMON_MODULES_DAMOS_STATS_PARAMS(damon_reclaim_stat,
reclaim_tried_regions, reclaimed_regions, quota_exceeds);
static struct damon_ctx *ctx;
static struct damon_target *target;
static struct damos *damon_reclaim_new_scheme(void)
{
struct damos_access_pattern pattern = {
/* Find regions having PAGE_SIZE or larger size */
.min_sz_region = PAGE_SIZE,
.max_sz_region = ULONG_MAX,
/* and not accessed at all */
.min_nr_accesses = 0,
.max_nr_accesses = 0,
/* for min_age or more micro-seconds */
.min_age_region = min_age /
damon_reclaim_mon_attrs.aggr_interval,
.max_age_region = UINT_MAX,
};
return damon_new_scheme(
&pattern,
/* page out those, as soon as found */
DAMOS_PAGEOUT,
/* under the quota. */
&damon_reclaim_quota,
/* (De)activate this according to the watermarks. */
&damon_reclaim_wmarks);
}
static int damon_reclaim_apply_parameters(void)
{
struct damos *scheme;
struct damos_filter *filter;
int err = 0;
err = damon_set_attrs(ctx, &damon_reclaim_mon_attrs);
if (err)
return err;
/* Will be freed by next 'damon_set_schemes()' below */
scheme = damon_reclaim_new_scheme();
if (!scheme)
return -ENOMEM;
if (skip_anon) {
filter = damos_new_filter(DAMOS_FILTER_TYPE_ANON, true);
if (!filter) {
/* Will be freed by next 'damon_set_schemes()' below */
damon_destroy_scheme(scheme);
return -ENOMEM;
}
damos_add_filter(scheme, filter);
}
damon_set_schemes(ctx, &scheme, 1);
return damon_set_region_biggest_system_ram_default(target,
&monitor_region_start,
&monitor_region_end);
}
static int damon_reclaim_turn(bool on)
{
int err;
if (!on) {
err = damon_stop(&ctx, 1);
if (!err)
kdamond_pid = -1;
return err;
}
err = damon_reclaim_apply_parameters();
if (err)
return err;
err = damon_start(&ctx, 1, true);
if (err)
return err;
kdamond_pid = ctx->kdamond->pid;
return 0;
}
static int damon_reclaim_enabled_store(const char *val,
const struct kernel_param *kp)
{
bool is_enabled = enabled;
bool enable;
int err;
err = kstrtobool(val, &enable);
if (err)
return err;
if (is_enabled == enable)
return 0;
/* Called before init function. The function will handle this. */
if (!ctx)
goto set_param_out;
err = damon_reclaim_turn(enable);
if (err)
return err;
set_param_out:
enabled = enable;
return err;
}
static const struct kernel_param_ops enabled_param_ops = {
.set = damon_reclaim_enabled_store,
.get = param_get_bool,
};
module_param_cb(enabled, &enabled_param_ops, &enabled, 0600);
MODULE_PARM_DESC(enabled,
"Enable or disable DAMON_RECLAIM (default: disabled)");
static int damon_reclaim_handle_commit_inputs(void)
{
int err;
if (!commit_inputs)
return 0;
err = damon_reclaim_apply_parameters();
commit_inputs = false;
return err;
}
static int damon_reclaim_after_aggregation(struct damon_ctx *c)
{
struct damos *s;
/* update the stats parameter */
damon_for_each_scheme(s, c)
damon_reclaim_stat = s->stat;
return damon_reclaim_handle_commit_inputs();
}
static int damon_reclaim_after_wmarks_check(struct damon_ctx *c)
{
return damon_reclaim_handle_commit_inputs();
}
static int __init damon_reclaim_init(void)
{
int err = damon_modules_new_paddr_ctx_target(&ctx, &target);
if (err)
return err;
ctx->callback.after_wmarks_check = damon_reclaim_after_wmarks_check;
ctx->callback.after_aggregation = damon_reclaim_after_aggregation;
/* 'enabled' has set before this function, probably via command line */
if (enabled)
err = damon_reclaim_turn(true);
return err;
}
module_init(damon_reclaim_init);
| linux-master | mm/damon/reclaim.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Common Primitives for DAMON Modules
*
* Author: SeongJae Park <[email protected]>
*/
#include <linux/damon.h>
#include "modules-common.h"
/*
* Allocate, set, and return a DAMON context for the physical address space.
* @ctxp: Pointer to save the point to the newly created context
* @targetp: Pointer to save the point to the newly created target
*/
int damon_modules_new_paddr_ctx_target(struct damon_ctx **ctxp,
struct damon_target **targetp)
{
struct damon_ctx *ctx;
struct damon_target *target;
ctx = damon_new_ctx();
if (!ctx)
return -ENOMEM;
if (damon_select_ops(ctx, DAMON_OPS_PADDR)) {
damon_destroy_ctx(ctx);
return -EINVAL;
}
target = damon_new_target();
if (!target) {
damon_destroy_ctx(ctx);
return -ENOMEM;
}
damon_add_target(ctx, target);
*ctxp = ctx;
*targetp = target;
return 0;
}
| linux-master | mm/damon/modules-common.c |
// SPDX-License-Identifier: GPL-2.0
/*
* DAMON-based LRU-lists Sorting
*
* Author: SeongJae Park <[email protected]>
*/
#define pr_fmt(fmt) "damon-lru-sort: " fmt
#include <linux/damon.h>
#include <linux/kstrtox.h>
#include <linux/module.h>
#include "modules-common.h"
#ifdef MODULE_PARAM_PREFIX
#undef MODULE_PARAM_PREFIX
#endif
#define MODULE_PARAM_PREFIX "damon_lru_sort."
/*
* Enable or disable DAMON_LRU_SORT.
*
* You can enable DAMON_LRU_SORT by setting the value of this parameter as
* ``Y``. Setting it as ``N`` disables DAMON_LRU_SORT. Note that
* DAMON_LRU_SORT could do no real monitoring and LRU-lists sorting due to the
* watermarks-based activation condition. Refer to below descriptions for the
* watermarks parameter for this.
*/
static bool enabled __read_mostly;
/*
* Make DAMON_LRU_SORT reads the input parameters again, except ``enabled``.
*
* Input parameters that updated while DAMON_LRU_SORT is running are not
* applied by default. Once this parameter is set as ``Y``, DAMON_LRU_SORT
* reads values of parametrs except ``enabled`` again. Once the re-reading is
* done, this parameter is set as ``N``. If invalid parameters are found while
* the re-reading, DAMON_LRU_SORT will be disabled.
*/
static bool commit_inputs __read_mostly;
module_param(commit_inputs, bool, 0600);
/*
* Access frequency threshold for hot memory regions identification in permil.
*
* If a memory region is accessed in frequency of this or higher,
* DAMON_LRU_SORT identifies the region as hot, and mark it as accessed on the
* LRU list, so that it could not be reclaimed under memory pressure. 50% by
* default.
*/
static unsigned long hot_thres_access_freq = 500;
module_param(hot_thres_access_freq, ulong, 0600);
/*
* Time threshold for cold memory regions identification in microseconds.
*
* If a memory region is not accessed for this or longer time, DAMON_LRU_SORT
* identifies the region as cold, and mark it as unaccessed on the LRU list, so
* that it could be reclaimed first under memory pressure. 120 seconds by
* default.
*/
static unsigned long cold_min_age __read_mostly = 120000000;
module_param(cold_min_age, ulong, 0600);
static struct damos_quota damon_lru_sort_quota = {
/* Use up to 10 ms per 1 sec, by default */
.ms = 10,
.sz = 0,
.reset_interval = 1000,
/* Within the quota, mark hotter regions accessed first. */
.weight_sz = 0,
.weight_nr_accesses = 1,
.weight_age = 0,
};
DEFINE_DAMON_MODULES_DAMOS_TIME_QUOTA(damon_lru_sort_quota);
static struct damos_watermarks damon_lru_sort_wmarks = {
.metric = DAMOS_WMARK_FREE_MEM_RATE,
.interval = 5000000, /* 5 seconds */
.high = 200, /* 20 percent */
.mid = 150, /* 15 percent */
.low = 50, /* 5 percent */
};
DEFINE_DAMON_MODULES_WMARKS_PARAMS(damon_lru_sort_wmarks);
static struct damon_attrs damon_lru_sort_mon_attrs = {
.sample_interval = 5000, /* 5 ms */
.aggr_interval = 100000, /* 100 ms */
.ops_update_interval = 0,
.min_nr_regions = 10,
.max_nr_regions = 1000,
};
DEFINE_DAMON_MODULES_MON_ATTRS_PARAMS(damon_lru_sort_mon_attrs);
/*
* Start of the target memory region in physical address.
*
* The start physical address of memory region that DAMON_LRU_SORT will do work
* against. By default, biggest System RAM is used as the region.
*/
static unsigned long monitor_region_start __read_mostly;
module_param(monitor_region_start, ulong, 0600);
/*
* End of the target memory region in physical address.
*
* The end physical address of memory region that DAMON_LRU_SORT will do work
* against. By default, biggest System RAM is used as the region.
*/
static unsigned long monitor_region_end __read_mostly;
module_param(monitor_region_end, ulong, 0600);
/*
* PID of the DAMON thread
*
* If DAMON_LRU_SORT is enabled, this becomes the PID of the worker thread.
* Else, -1.
*/
static int kdamond_pid __read_mostly = -1;
module_param(kdamond_pid, int, 0400);
static struct damos_stat damon_lru_sort_hot_stat;
DEFINE_DAMON_MODULES_DAMOS_STATS_PARAMS(damon_lru_sort_hot_stat,
lru_sort_tried_hot_regions, lru_sorted_hot_regions,
hot_quota_exceeds);
static struct damos_stat damon_lru_sort_cold_stat;
DEFINE_DAMON_MODULES_DAMOS_STATS_PARAMS(damon_lru_sort_cold_stat,
lru_sort_tried_cold_regions, lru_sorted_cold_regions,
cold_quota_exceeds);
static struct damos_access_pattern damon_lru_sort_stub_pattern = {
/* Find regions having PAGE_SIZE or larger size */
.min_sz_region = PAGE_SIZE,
.max_sz_region = ULONG_MAX,
/* no matter its access frequency */
.min_nr_accesses = 0,
.max_nr_accesses = UINT_MAX,
/* no matter its age */
.min_age_region = 0,
.max_age_region = UINT_MAX,
};
static struct damon_ctx *ctx;
static struct damon_target *target;
static struct damos *damon_lru_sort_new_scheme(
struct damos_access_pattern *pattern, enum damos_action action)
{
struct damos_quota quota = damon_lru_sort_quota;
/* Use half of total quota for hot/cold pages sorting */
quota.ms = quota.ms / 2;
return damon_new_scheme(
/* find the pattern, and */
pattern,
/* (de)prioritize on LRU-lists */
action,
/* under the quota. */
"a,
/* (De)activate this according to the watermarks. */
&damon_lru_sort_wmarks);
}
/* Create a DAMON-based operation scheme for hot memory regions */
static struct damos *damon_lru_sort_new_hot_scheme(unsigned int hot_thres)
{
struct damos_access_pattern pattern = damon_lru_sort_stub_pattern;
pattern.min_nr_accesses = hot_thres;
return damon_lru_sort_new_scheme(&pattern, DAMOS_LRU_PRIO);
}
/* Create a DAMON-based operation scheme for cold memory regions */
static struct damos *damon_lru_sort_new_cold_scheme(unsigned int cold_thres)
{
struct damos_access_pattern pattern = damon_lru_sort_stub_pattern;
pattern.max_nr_accesses = 0;
pattern.min_age_region = cold_thres;
return damon_lru_sort_new_scheme(&pattern, DAMOS_LRU_DEPRIO);
}
static int damon_lru_sort_apply_parameters(void)
{
struct damos *scheme;
unsigned int hot_thres, cold_thres;
int err = 0;
err = damon_set_attrs(ctx, &damon_lru_sort_mon_attrs);
if (err)
return err;
/* aggr_interval / sample_interval is the maximum nr_accesses */
hot_thres = damon_lru_sort_mon_attrs.aggr_interval /
damon_lru_sort_mon_attrs.sample_interval *
hot_thres_access_freq / 1000;
scheme = damon_lru_sort_new_hot_scheme(hot_thres);
if (!scheme)
return -ENOMEM;
damon_set_schemes(ctx, &scheme, 1);
cold_thres = cold_min_age / damon_lru_sort_mon_attrs.aggr_interval;
scheme = damon_lru_sort_new_cold_scheme(cold_thres);
if (!scheme)
return -ENOMEM;
damon_add_scheme(ctx, scheme);
return damon_set_region_biggest_system_ram_default(target,
&monitor_region_start,
&monitor_region_end);
}
static int damon_lru_sort_turn(bool on)
{
int err;
if (!on) {
err = damon_stop(&ctx, 1);
if (!err)
kdamond_pid = -1;
return err;
}
err = damon_lru_sort_apply_parameters();
if (err)
return err;
err = damon_start(&ctx, 1, true);
if (err)
return err;
kdamond_pid = ctx->kdamond->pid;
return 0;
}
static int damon_lru_sort_enabled_store(const char *val,
const struct kernel_param *kp)
{
bool is_enabled = enabled;
bool enable;
int err;
err = kstrtobool(val, &enable);
if (err)
return err;
if (is_enabled == enable)
return 0;
/* Called before init function. The function will handle this. */
if (!ctx)
goto set_param_out;
err = damon_lru_sort_turn(enable);
if (err)
return err;
set_param_out:
enabled = enable;
return err;
}
static const struct kernel_param_ops enabled_param_ops = {
.set = damon_lru_sort_enabled_store,
.get = param_get_bool,
};
module_param_cb(enabled, &enabled_param_ops, &enabled, 0600);
MODULE_PARM_DESC(enabled,
"Enable or disable DAMON_LRU_SORT (default: disabled)");
static int damon_lru_sort_handle_commit_inputs(void)
{
int err;
if (!commit_inputs)
return 0;
err = damon_lru_sort_apply_parameters();
commit_inputs = false;
return err;
}
static int damon_lru_sort_after_aggregation(struct damon_ctx *c)
{
struct damos *s;
/* update the stats parameter */
damon_for_each_scheme(s, c) {
if (s->action == DAMOS_LRU_PRIO)
damon_lru_sort_hot_stat = s->stat;
else if (s->action == DAMOS_LRU_DEPRIO)
damon_lru_sort_cold_stat = s->stat;
}
return damon_lru_sort_handle_commit_inputs();
}
static int damon_lru_sort_after_wmarks_check(struct damon_ctx *c)
{
return damon_lru_sort_handle_commit_inputs();
}
static int __init damon_lru_sort_init(void)
{
int err = damon_modules_new_paddr_ctx_target(&ctx, &target);
if (err)
return err;
ctx->callback.after_wmarks_check = damon_lru_sort_after_wmarks_check;
ctx->callback.after_aggregation = damon_lru_sort_after_aggregation;
/* 'enabled' has set before this function, probably via command line */
if (enabled)
err = damon_lru_sort_turn(true);
return err;
}
module_init(damon_lru_sort_init);
| linux-master | mm/damon/lru_sort.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Common Primitives for Data Access Monitoring
*
* Author: SeongJae Park <[email protected]>
*/
#include <linux/mmu_notifier.h>
#include <linux/page_idle.h>
#include <linux/pagemap.h>
#include <linux/rmap.h>
#include "ops-common.h"
/*
* Get an online page for a pfn if it's in the LRU list. Otherwise, returns
* NULL.
*
* The body of this function is stolen from the 'page_idle_get_folio()'. We
* steal rather than reuse it because the code is quite simple.
*/
struct folio *damon_get_folio(unsigned long pfn)
{
struct page *page = pfn_to_online_page(pfn);
struct folio *folio;
if (!page || PageTail(page))
return NULL;
folio = page_folio(page);
if (!folio_test_lru(folio) || !folio_try_get(folio))
return NULL;
if (unlikely(page_folio(page) != folio || !folio_test_lru(folio))) {
folio_put(folio);
folio = NULL;
}
return folio;
}
void damon_ptep_mkold(pte_t *pte, struct vm_area_struct *vma, unsigned long addr)
{
struct folio *folio = damon_get_folio(pte_pfn(ptep_get(pte)));
if (!folio)
return;
if (ptep_clear_young_notify(vma, addr, pte))
folio_set_young(folio);
folio_set_idle(folio);
folio_put(folio);
}
void damon_pmdp_mkold(pmd_t *pmd, struct vm_area_struct *vma, unsigned long addr)
{
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
struct folio *folio = damon_get_folio(pmd_pfn(pmdp_get(pmd)));
if (!folio)
return;
if (pmdp_clear_young_notify(vma, addr, pmd))
folio_set_young(folio);
folio_set_idle(folio);
folio_put(folio);
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
}
#define DAMON_MAX_SUBSCORE (100)
#define DAMON_MAX_AGE_IN_LOG (32)
int damon_hot_score(struct damon_ctx *c, struct damon_region *r,
struct damos *s)
{
unsigned int max_nr_accesses;
int freq_subscore;
unsigned int age_in_sec;
int age_in_log, age_subscore;
unsigned int freq_weight = s->quota.weight_nr_accesses;
unsigned int age_weight = s->quota.weight_age;
int hotness;
max_nr_accesses = c->attrs.aggr_interval / c->attrs.sample_interval;
freq_subscore = r->nr_accesses * DAMON_MAX_SUBSCORE / max_nr_accesses;
age_in_sec = (unsigned long)r->age * c->attrs.aggr_interval / 1000000;
for (age_in_log = 0; age_in_log < DAMON_MAX_AGE_IN_LOG && age_in_sec;
age_in_log++, age_in_sec >>= 1)
;
/* If frequency is 0, higher age means it's colder */
if (freq_subscore == 0)
age_in_log *= -1;
/*
* Now age_in_log is in [-DAMON_MAX_AGE_IN_LOG, DAMON_MAX_AGE_IN_LOG].
* Scale it to be in [0, 100] and set it as age subscore.
*/
age_in_log += DAMON_MAX_AGE_IN_LOG;
age_subscore = age_in_log * DAMON_MAX_SUBSCORE /
DAMON_MAX_AGE_IN_LOG / 2;
hotness = (freq_weight * freq_subscore + age_weight * age_subscore);
if (freq_weight + age_weight)
hotness /= freq_weight + age_weight;
/*
* Transform it to fit in [0, DAMOS_MAX_SCORE]
*/
hotness = hotness * DAMOS_MAX_SCORE / DAMON_MAX_SUBSCORE;
return hotness;
}
int damon_cold_score(struct damon_ctx *c, struct damon_region *r,
struct damos *s)
{
int hotness = damon_hot_score(c, r, s);
/* Return coldness of the region */
return DAMOS_MAX_SCORE - hotness;
}
| linux-master | mm/damon/ops-common.c |
// SPDX-License-Identifier: GPL-2.0
/*
* linux/ipc/msg.c
* Copyright (C) 1992 Krishna Balasubramanian
*
* Removed all the remaining kerneld mess
* Catch the -EFAULT stuff properly
* Use GFP_KERNEL for messages as in 1.2
* Fixed up the unchecked user space derefs
* Copyright (C) 1998 Alan Cox & Andi Kleen
*
* /proc/sysvipc/msg support (c) 1999 Dragos Acostachioaie <[email protected]>
*
* mostly rewritten, threaded and wake-one semantics added
* MSGMAX limit removed, sysctl's added
* (c) 1999 Manfred Spraul <[email protected]>
*
* support for audit of ipc object properties and permission changes
* Dustin Kirkland <[email protected]>
*
* namespaces support
* OpenVZ, SWsoft Inc.
* Pavel Emelianov <[email protected]>
*/
#include <linux/capability.h>
#include <linux/msg.h>
#include <linux/spinlock.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/proc_fs.h>
#include <linux/list.h>
#include <linux/security.h>
#include <linux/sched/wake_q.h>
#include <linux/syscalls.h>
#include <linux/audit.h>
#include <linux/seq_file.h>
#include <linux/rwsem.h>
#include <linux/nsproxy.h>
#include <linux/ipc_namespace.h>
#include <linux/rhashtable.h>
#include <linux/percpu_counter.h>
#include <asm/current.h>
#include <linux/uaccess.h>
#include "util.h"
/* one msq_queue structure for each present queue on the system */
struct msg_queue {
struct kern_ipc_perm q_perm;
time64_t q_stime; /* last msgsnd time */
time64_t q_rtime; /* last msgrcv time */
time64_t q_ctime; /* last change time */
unsigned long q_cbytes; /* current number of bytes on queue */
unsigned long q_qnum; /* number of messages in queue */
unsigned long q_qbytes; /* max number of bytes on queue */
struct pid *q_lspid; /* pid of last msgsnd */
struct pid *q_lrpid; /* last receive pid */
struct list_head q_messages;
struct list_head q_receivers;
struct list_head q_senders;
} __randomize_layout;
/*
* MSG_BARRIER Locking:
*
* Similar to the optimization used in ipc/mqueue.c, one syscall return path
* does not acquire any locks when it sees that a message exists in
* msg_receiver.r_msg. Therefore r_msg is set using smp_store_release()
* and accessed using READ_ONCE()+smp_acquire__after_ctrl_dep(). In addition,
* wake_q_add_safe() is used. See ipc/mqueue.c for more details
*/
/* one msg_receiver structure for each sleeping receiver */
struct msg_receiver {
struct list_head r_list;
struct task_struct *r_tsk;
int r_mode;
long r_msgtype;
long r_maxsize;
struct msg_msg *r_msg;
};
/* one msg_sender for each sleeping sender */
struct msg_sender {
struct list_head list;
struct task_struct *tsk;
size_t msgsz;
};
#define SEARCH_ANY 1
#define SEARCH_EQUAL 2
#define SEARCH_NOTEQUAL 3
#define SEARCH_LESSEQUAL 4
#define SEARCH_NUMBER 5
#define msg_ids(ns) ((ns)->ids[IPC_MSG_IDS])
static inline struct msg_queue *msq_obtain_object(struct ipc_namespace *ns, int id)
{
struct kern_ipc_perm *ipcp = ipc_obtain_object_idr(&msg_ids(ns), id);
if (IS_ERR(ipcp))
return ERR_CAST(ipcp);
return container_of(ipcp, struct msg_queue, q_perm);
}
static inline struct msg_queue *msq_obtain_object_check(struct ipc_namespace *ns,
int id)
{
struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&msg_ids(ns), id);
if (IS_ERR(ipcp))
return ERR_CAST(ipcp);
return container_of(ipcp, struct msg_queue, q_perm);
}
static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s)
{
ipc_rmid(&msg_ids(ns), &s->q_perm);
}
static void msg_rcu_free(struct rcu_head *head)
{
struct kern_ipc_perm *p = container_of(head, struct kern_ipc_perm, rcu);
struct msg_queue *msq = container_of(p, struct msg_queue, q_perm);
security_msg_queue_free(&msq->q_perm);
kfree(msq);
}
/**
* newque - Create a new msg queue
* @ns: namespace
* @params: ptr to the structure that contains the key and msgflg
*
* Called with msg_ids.rwsem held (writer)
*/
static int newque(struct ipc_namespace *ns, struct ipc_params *params)
{
struct msg_queue *msq;
int retval;
key_t key = params->key;
int msgflg = params->flg;
msq = kmalloc(sizeof(*msq), GFP_KERNEL_ACCOUNT);
if (unlikely(!msq))
return -ENOMEM;
msq->q_perm.mode = msgflg & S_IRWXUGO;
msq->q_perm.key = key;
msq->q_perm.security = NULL;
retval = security_msg_queue_alloc(&msq->q_perm);
if (retval) {
kfree(msq);
return retval;
}
msq->q_stime = msq->q_rtime = 0;
msq->q_ctime = ktime_get_real_seconds();
msq->q_cbytes = msq->q_qnum = 0;
msq->q_qbytes = ns->msg_ctlmnb;
msq->q_lspid = msq->q_lrpid = NULL;
INIT_LIST_HEAD(&msq->q_messages);
INIT_LIST_HEAD(&msq->q_receivers);
INIT_LIST_HEAD(&msq->q_senders);
/* ipc_addid() locks msq upon success. */
retval = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni);
if (retval < 0) {
ipc_rcu_putref(&msq->q_perm, msg_rcu_free);
return retval;
}
ipc_unlock_object(&msq->q_perm);
rcu_read_unlock();
return msq->q_perm.id;
}
static inline bool msg_fits_inqueue(struct msg_queue *msq, size_t msgsz)
{
return msgsz + msq->q_cbytes <= msq->q_qbytes &&
1 + msq->q_qnum <= msq->q_qbytes;
}
static inline void ss_add(struct msg_queue *msq,
struct msg_sender *mss, size_t msgsz)
{
mss->tsk = current;
mss->msgsz = msgsz;
/*
* No memory barrier required: we did ipc_lock_object(),
* and the waker obtains that lock before calling wake_q_add().
*/
__set_current_state(TASK_INTERRUPTIBLE);
list_add_tail(&mss->list, &msq->q_senders);
}
static inline void ss_del(struct msg_sender *mss)
{
if (mss->list.next)
list_del(&mss->list);
}
static void ss_wakeup(struct msg_queue *msq,
struct wake_q_head *wake_q, bool kill)
{
struct msg_sender *mss, *t;
struct task_struct *stop_tsk = NULL;
struct list_head *h = &msq->q_senders;
list_for_each_entry_safe(mss, t, h, list) {
if (kill)
mss->list.next = NULL;
/*
* Stop at the first task we don't wakeup,
* we've already iterated the original
* sender queue.
*/
else if (stop_tsk == mss->tsk)
break;
/*
* We are not in an EIDRM scenario here, therefore
* verify that we really need to wakeup the task.
* To maintain current semantics and wakeup order,
* move the sender to the tail on behalf of the
* blocked task.
*/
else if (!msg_fits_inqueue(msq, mss->msgsz)) {
if (!stop_tsk)
stop_tsk = mss->tsk;
list_move_tail(&mss->list, &msq->q_senders);
continue;
}
wake_q_add(wake_q, mss->tsk);
}
}
static void expunge_all(struct msg_queue *msq, int res,
struct wake_q_head *wake_q)
{
struct msg_receiver *msr, *t;
list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) {
struct task_struct *r_tsk;
r_tsk = get_task_struct(msr->r_tsk);
/* see MSG_BARRIER for purpose/pairing */
smp_store_release(&msr->r_msg, ERR_PTR(res));
wake_q_add_safe(wake_q, r_tsk);
}
}
/*
* freeque() wakes up waiters on the sender and receiver waiting queue,
* removes the message queue from message queue ID IDR, and cleans up all the
* messages associated with this queue.
*
* msg_ids.rwsem (writer) and the spinlock for this message queue are held
* before freeque() is called. msg_ids.rwsem remains locked on exit.
*/
static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
__releases(RCU)
__releases(&msq->q_perm)
{
struct msg_msg *msg, *t;
struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
DEFINE_WAKE_Q(wake_q);
expunge_all(msq, -EIDRM, &wake_q);
ss_wakeup(msq, &wake_q, true);
msg_rmid(ns, msq);
ipc_unlock_object(&msq->q_perm);
wake_up_q(&wake_q);
rcu_read_unlock();
list_for_each_entry_safe(msg, t, &msq->q_messages, m_list) {
percpu_counter_sub_local(&ns->percpu_msg_hdrs, 1);
free_msg(msg);
}
percpu_counter_sub_local(&ns->percpu_msg_bytes, msq->q_cbytes);
ipc_update_pid(&msq->q_lspid, NULL);
ipc_update_pid(&msq->q_lrpid, NULL);
ipc_rcu_putref(&msq->q_perm, msg_rcu_free);
}
long ksys_msgget(key_t key, int msgflg)
{
struct ipc_namespace *ns;
static const struct ipc_ops msg_ops = {
.getnew = newque,
.associate = security_msg_queue_associate,
};
struct ipc_params msg_params;
ns = current->nsproxy->ipc_ns;
msg_params.key = key;
msg_params.flg = msgflg;
return ipcget(ns, &msg_ids(ns), &msg_ops, &msg_params);
}
SYSCALL_DEFINE2(msgget, key_t, key, int, msgflg)
{
return ksys_msgget(key, msgflg);
}
static inline unsigned long
copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version)
{
switch (version) {
case IPC_64:
return copy_to_user(buf, in, sizeof(*in));
case IPC_OLD:
{
struct msqid_ds out;
memset(&out, 0, sizeof(out));
ipc64_perm_to_ipc_perm(&in->msg_perm, &out.msg_perm);
out.msg_stime = in->msg_stime;
out.msg_rtime = in->msg_rtime;
out.msg_ctime = in->msg_ctime;
if (in->msg_cbytes > USHRT_MAX)
out.msg_cbytes = USHRT_MAX;
else
out.msg_cbytes = in->msg_cbytes;
out.msg_lcbytes = in->msg_cbytes;
if (in->msg_qnum > USHRT_MAX)
out.msg_qnum = USHRT_MAX;
else
out.msg_qnum = in->msg_qnum;
if (in->msg_qbytes > USHRT_MAX)
out.msg_qbytes = USHRT_MAX;
else
out.msg_qbytes = in->msg_qbytes;
out.msg_lqbytes = in->msg_qbytes;
out.msg_lspid = in->msg_lspid;
out.msg_lrpid = in->msg_lrpid;
return copy_to_user(buf, &out, sizeof(out));
}
default:
return -EINVAL;
}
}
static inline unsigned long
copy_msqid_from_user(struct msqid64_ds *out, void __user *buf, int version)
{
switch (version) {
case IPC_64:
if (copy_from_user(out, buf, sizeof(*out)))
return -EFAULT;
return 0;
case IPC_OLD:
{
struct msqid_ds tbuf_old;
if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
return -EFAULT;
out->msg_perm.uid = tbuf_old.msg_perm.uid;
out->msg_perm.gid = tbuf_old.msg_perm.gid;
out->msg_perm.mode = tbuf_old.msg_perm.mode;
if (tbuf_old.msg_qbytes == 0)
out->msg_qbytes = tbuf_old.msg_lqbytes;
else
out->msg_qbytes = tbuf_old.msg_qbytes;
return 0;
}
default:
return -EINVAL;
}
}
/*
* This function handles some msgctl commands which require the rwsem
* to be held in write mode.
* NOTE: no locks must be held, the rwsem is taken inside this function.
*/
static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd,
struct ipc64_perm *perm, int msg_qbytes)
{
struct kern_ipc_perm *ipcp;
struct msg_queue *msq;
int err;
down_write(&msg_ids(ns).rwsem);
rcu_read_lock();
ipcp = ipcctl_obtain_check(ns, &msg_ids(ns), msqid, cmd,
perm, msg_qbytes);
if (IS_ERR(ipcp)) {
err = PTR_ERR(ipcp);
goto out_unlock1;
}
msq = container_of(ipcp, struct msg_queue, q_perm);
err = security_msg_queue_msgctl(&msq->q_perm, cmd);
if (err)
goto out_unlock1;
switch (cmd) {
case IPC_RMID:
ipc_lock_object(&msq->q_perm);
/* freeque unlocks the ipc object and rcu */
freeque(ns, ipcp);
goto out_up;
case IPC_SET:
{
DEFINE_WAKE_Q(wake_q);
if (msg_qbytes > ns->msg_ctlmnb &&
!capable(CAP_SYS_RESOURCE)) {
err = -EPERM;
goto out_unlock1;
}
ipc_lock_object(&msq->q_perm);
err = ipc_update_perm(perm, ipcp);
if (err)
goto out_unlock0;
msq->q_qbytes = msg_qbytes;
msq->q_ctime = ktime_get_real_seconds();
/*
* Sleeping receivers might be excluded by
* stricter permissions.
*/
expunge_all(msq, -EAGAIN, &wake_q);
/*
* Sleeping senders might be able to send
* due to a larger queue size.
*/
ss_wakeup(msq, &wake_q, false);
ipc_unlock_object(&msq->q_perm);
wake_up_q(&wake_q);
goto out_unlock1;
}
default:
err = -EINVAL;
goto out_unlock1;
}
out_unlock0:
ipc_unlock_object(&msq->q_perm);
out_unlock1:
rcu_read_unlock();
out_up:
up_write(&msg_ids(ns).rwsem);
return err;
}
static int msgctl_info(struct ipc_namespace *ns, int msqid,
int cmd, struct msginfo *msginfo)
{
int err;
int max_idx;
/*
* We must not return kernel stack data.
* due to padding, it's not enough
* to set all member fields.
*/
err = security_msg_queue_msgctl(NULL, cmd);
if (err)
return err;
memset(msginfo, 0, sizeof(*msginfo));
msginfo->msgmni = ns->msg_ctlmni;
msginfo->msgmax = ns->msg_ctlmax;
msginfo->msgmnb = ns->msg_ctlmnb;
msginfo->msgssz = MSGSSZ;
msginfo->msgseg = MSGSEG;
down_read(&msg_ids(ns).rwsem);
if (cmd == MSG_INFO)
msginfo->msgpool = msg_ids(ns).in_use;
max_idx = ipc_get_maxidx(&msg_ids(ns));
up_read(&msg_ids(ns).rwsem);
if (cmd == MSG_INFO) {
msginfo->msgmap = min_t(int,
percpu_counter_sum(&ns->percpu_msg_hdrs),
INT_MAX);
msginfo->msgtql = min_t(int,
percpu_counter_sum(&ns->percpu_msg_bytes),
INT_MAX);
} else {
msginfo->msgmap = MSGMAP;
msginfo->msgpool = MSGPOOL;
msginfo->msgtql = MSGTQL;
}
return (max_idx < 0) ? 0 : max_idx;
}
static int msgctl_stat(struct ipc_namespace *ns, int msqid,
int cmd, struct msqid64_ds *p)
{
struct msg_queue *msq;
int err;
memset(p, 0, sizeof(*p));
rcu_read_lock();
if (cmd == MSG_STAT || cmd == MSG_STAT_ANY) {
msq = msq_obtain_object(ns, msqid);
if (IS_ERR(msq)) {
err = PTR_ERR(msq);
goto out_unlock;
}
} else { /* IPC_STAT */
msq = msq_obtain_object_check(ns, msqid);
if (IS_ERR(msq)) {
err = PTR_ERR(msq);
goto out_unlock;
}
}
/* see comment for SHM_STAT_ANY */
if (cmd == MSG_STAT_ANY)
audit_ipc_obj(&msq->q_perm);
else {
err = -EACCES;
if (ipcperms(ns, &msq->q_perm, S_IRUGO))
goto out_unlock;
}
err = security_msg_queue_msgctl(&msq->q_perm, cmd);
if (err)
goto out_unlock;
ipc_lock_object(&msq->q_perm);
if (!ipc_valid_object(&msq->q_perm)) {
ipc_unlock_object(&msq->q_perm);
err = -EIDRM;
goto out_unlock;
}
kernel_to_ipc64_perm(&msq->q_perm, &p->msg_perm);
p->msg_stime = msq->q_stime;
p->msg_rtime = msq->q_rtime;
p->msg_ctime = msq->q_ctime;
#ifndef CONFIG_64BIT
p->msg_stime_high = msq->q_stime >> 32;
p->msg_rtime_high = msq->q_rtime >> 32;
p->msg_ctime_high = msq->q_ctime >> 32;
#endif
p->msg_cbytes = msq->q_cbytes;
p->msg_qnum = msq->q_qnum;
p->msg_qbytes = msq->q_qbytes;
p->msg_lspid = pid_vnr(msq->q_lspid);
p->msg_lrpid = pid_vnr(msq->q_lrpid);
if (cmd == IPC_STAT) {
/*
* As defined in SUS:
* Return 0 on success
*/
err = 0;
} else {
/*
* MSG_STAT and MSG_STAT_ANY (both Linux specific)
* Return the full id, including the sequence number
*/
err = msq->q_perm.id;
}
ipc_unlock_object(&msq->q_perm);
out_unlock:
rcu_read_unlock();
return err;
}
static long ksys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf, int version)
{
struct ipc_namespace *ns;
struct msqid64_ds msqid64;
int err;
if (msqid < 0 || cmd < 0)
return -EINVAL;
ns = current->nsproxy->ipc_ns;
switch (cmd) {
case IPC_INFO:
case MSG_INFO: {
struct msginfo msginfo;
err = msgctl_info(ns, msqid, cmd, &msginfo);
if (err < 0)
return err;
if (copy_to_user(buf, &msginfo, sizeof(struct msginfo)))
err = -EFAULT;
return err;
}
case MSG_STAT: /* msqid is an index rather than a msg queue id */
case MSG_STAT_ANY:
case IPC_STAT:
err = msgctl_stat(ns, msqid, cmd, &msqid64);
if (err < 0)
return err;
if (copy_msqid_to_user(buf, &msqid64, version))
err = -EFAULT;
return err;
case IPC_SET:
if (copy_msqid_from_user(&msqid64, buf, version))
return -EFAULT;
return msgctl_down(ns, msqid, cmd, &msqid64.msg_perm,
msqid64.msg_qbytes);
case IPC_RMID:
return msgctl_down(ns, msqid, cmd, NULL, 0);
default:
return -EINVAL;
}
}
SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
{
return ksys_msgctl(msqid, cmd, buf, IPC_64);
}
#ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
long ksys_old_msgctl(int msqid, int cmd, struct msqid_ds __user *buf)
{
int version = ipc_parse_version(&cmd);
return ksys_msgctl(msqid, cmd, buf, version);
}
SYSCALL_DEFINE3(old_msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
{
return ksys_old_msgctl(msqid, cmd, buf);
}
#endif
#ifdef CONFIG_COMPAT
struct compat_msqid_ds {
struct compat_ipc_perm msg_perm;
compat_uptr_t msg_first;
compat_uptr_t msg_last;
old_time32_t msg_stime;
old_time32_t msg_rtime;
old_time32_t msg_ctime;
compat_ulong_t msg_lcbytes;
compat_ulong_t msg_lqbytes;
unsigned short msg_cbytes;
unsigned short msg_qnum;
unsigned short msg_qbytes;
compat_ipc_pid_t msg_lspid;
compat_ipc_pid_t msg_lrpid;
};
static int copy_compat_msqid_from_user(struct msqid64_ds *out, void __user *buf,
int version)
{
memset(out, 0, sizeof(*out));
if (version == IPC_64) {
struct compat_msqid64_ds __user *p = buf;
if (get_compat_ipc64_perm(&out->msg_perm, &p->msg_perm))
return -EFAULT;
if (get_user(out->msg_qbytes, &p->msg_qbytes))
return -EFAULT;
} else {
struct compat_msqid_ds __user *p = buf;
if (get_compat_ipc_perm(&out->msg_perm, &p->msg_perm))
return -EFAULT;
if (get_user(out->msg_qbytes, &p->msg_qbytes))
return -EFAULT;
}
return 0;
}
static int copy_compat_msqid_to_user(void __user *buf, struct msqid64_ds *in,
int version)
{
if (version == IPC_64) {
struct compat_msqid64_ds v;
memset(&v, 0, sizeof(v));
to_compat_ipc64_perm(&v.msg_perm, &in->msg_perm);
v.msg_stime = lower_32_bits(in->msg_stime);
v.msg_stime_high = upper_32_bits(in->msg_stime);
v.msg_rtime = lower_32_bits(in->msg_rtime);
v.msg_rtime_high = upper_32_bits(in->msg_rtime);
v.msg_ctime = lower_32_bits(in->msg_ctime);
v.msg_ctime_high = upper_32_bits(in->msg_ctime);
v.msg_cbytes = in->msg_cbytes;
v.msg_qnum = in->msg_qnum;
v.msg_qbytes = in->msg_qbytes;
v.msg_lspid = in->msg_lspid;
v.msg_lrpid = in->msg_lrpid;
return copy_to_user(buf, &v, sizeof(v));
} else {
struct compat_msqid_ds v;
memset(&v, 0, sizeof(v));
to_compat_ipc_perm(&v.msg_perm, &in->msg_perm);
v.msg_stime = in->msg_stime;
v.msg_rtime = in->msg_rtime;
v.msg_ctime = in->msg_ctime;
v.msg_cbytes = in->msg_cbytes;
v.msg_qnum = in->msg_qnum;
v.msg_qbytes = in->msg_qbytes;
v.msg_lspid = in->msg_lspid;
v.msg_lrpid = in->msg_lrpid;
return copy_to_user(buf, &v, sizeof(v));
}
}
static long compat_ksys_msgctl(int msqid, int cmd, void __user *uptr, int version)
{
struct ipc_namespace *ns;
int err;
struct msqid64_ds msqid64;
ns = current->nsproxy->ipc_ns;
if (msqid < 0 || cmd < 0)
return -EINVAL;
switch (cmd & (~IPC_64)) {
case IPC_INFO:
case MSG_INFO: {
struct msginfo msginfo;
err = msgctl_info(ns, msqid, cmd, &msginfo);
if (err < 0)
return err;
if (copy_to_user(uptr, &msginfo, sizeof(struct msginfo)))
err = -EFAULT;
return err;
}
case IPC_STAT:
case MSG_STAT:
case MSG_STAT_ANY:
err = msgctl_stat(ns, msqid, cmd, &msqid64);
if (err < 0)
return err;
if (copy_compat_msqid_to_user(uptr, &msqid64, version))
err = -EFAULT;
return err;
case IPC_SET:
if (copy_compat_msqid_from_user(&msqid64, uptr, version))
return -EFAULT;
return msgctl_down(ns, msqid, cmd, &msqid64.msg_perm, msqid64.msg_qbytes);
case IPC_RMID:
return msgctl_down(ns, msqid, cmd, NULL, 0);
default:
return -EINVAL;
}
}
COMPAT_SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, void __user *, uptr)
{
return compat_ksys_msgctl(msqid, cmd, uptr, IPC_64);
}
#ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION
long compat_ksys_old_msgctl(int msqid, int cmd, void __user *uptr)
{
int version = compat_ipc_parse_version(&cmd);
return compat_ksys_msgctl(msqid, cmd, uptr, version);
}
COMPAT_SYSCALL_DEFINE3(old_msgctl, int, msqid, int, cmd, void __user *, uptr)
{
return compat_ksys_old_msgctl(msqid, cmd, uptr);
}
#endif
#endif
static int testmsg(struct msg_msg *msg, long type, int mode)
{
switch (mode) {
case SEARCH_ANY:
case SEARCH_NUMBER:
return 1;
case SEARCH_LESSEQUAL:
if (msg->m_type <= type)
return 1;
break;
case SEARCH_EQUAL:
if (msg->m_type == type)
return 1;
break;
case SEARCH_NOTEQUAL:
if (msg->m_type != type)
return 1;
break;
}
return 0;
}
static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg,
struct wake_q_head *wake_q)
{
struct msg_receiver *msr, *t;
list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) {
if (testmsg(msg, msr->r_msgtype, msr->r_mode) &&
!security_msg_queue_msgrcv(&msq->q_perm, msg, msr->r_tsk,
msr->r_msgtype, msr->r_mode)) {
list_del(&msr->r_list);
if (msr->r_maxsize < msg->m_ts) {
wake_q_add(wake_q, msr->r_tsk);
/* See expunge_all regarding memory barrier */
smp_store_release(&msr->r_msg, ERR_PTR(-E2BIG));
} else {
ipc_update_pid(&msq->q_lrpid, task_pid(msr->r_tsk));
msq->q_rtime = ktime_get_real_seconds();
wake_q_add(wake_q, msr->r_tsk);
/* See expunge_all regarding memory barrier */
smp_store_release(&msr->r_msg, msg);
return 1;
}
}
}
return 0;
}
static long do_msgsnd(int msqid, long mtype, void __user *mtext,
size_t msgsz, int msgflg)
{
struct msg_queue *msq;
struct msg_msg *msg;
int err;
struct ipc_namespace *ns;
DEFINE_WAKE_Q(wake_q);
ns = current->nsproxy->ipc_ns;
if (msgsz > ns->msg_ctlmax || (long) msgsz < 0 || msqid < 0)
return -EINVAL;
if (mtype < 1)
return -EINVAL;
msg = load_msg(mtext, msgsz);
if (IS_ERR(msg))
return PTR_ERR(msg);
msg->m_type = mtype;
msg->m_ts = msgsz;
rcu_read_lock();
msq = msq_obtain_object_check(ns, msqid);
if (IS_ERR(msq)) {
err = PTR_ERR(msq);
goto out_unlock1;
}
ipc_lock_object(&msq->q_perm);
for (;;) {
struct msg_sender s;
err = -EACCES;
if (ipcperms(ns, &msq->q_perm, S_IWUGO))
goto out_unlock0;
/* raced with RMID? */
if (!ipc_valid_object(&msq->q_perm)) {
err = -EIDRM;
goto out_unlock0;
}
err = security_msg_queue_msgsnd(&msq->q_perm, msg, msgflg);
if (err)
goto out_unlock0;
if (msg_fits_inqueue(msq, msgsz))
break;
/* queue full, wait: */
if (msgflg & IPC_NOWAIT) {
err = -EAGAIN;
goto out_unlock0;
}
/* enqueue the sender and prepare to block */
ss_add(msq, &s, msgsz);
if (!ipc_rcu_getref(&msq->q_perm)) {
err = -EIDRM;
goto out_unlock0;
}
ipc_unlock_object(&msq->q_perm);
rcu_read_unlock();
schedule();
rcu_read_lock();
ipc_lock_object(&msq->q_perm);
ipc_rcu_putref(&msq->q_perm, msg_rcu_free);
/* raced with RMID? */
if (!ipc_valid_object(&msq->q_perm)) {
err = -EIDRM;
goto out_unlock0;
}
ss_del(&s);
if (signal_pending(current)) {
err = -ERESTARTNOHAND;
goto out_unlock0;
}
}
ipc_update_pid(&msq->q_lspid, task_tgid(current));
msq->q_stime = ktime_get_real_seconds();
if (!pipelined_send(msq, msg, &wake_q)) {
/* no one is waiting for this message, enqueue it */
list_add_tail(&msg->m_list, &msq->q_messages);
msq->q_cbytes += msgsz;
msq->q_qnum++;
percpu_counter_add_local(&ns->percpu_msg_bytes, msgsz);
percpu_counter_add_local(&ns->percpu_msg_hdrs, 1);
}
err = 0;
msg = NULL;
out_unlock0:
ipc_unlock_object(&msq->q_perm);
wake_up_q(&wake_q);
out_unlock1:
rcu_read_unlock();
if (msg != NULL)
free_msg(msg);
return err;
}
long ksys_msgsnd(int msqid, struct msgbuf __user *msgp, size_t msgsz,
int msgflg)
{
long mtype;
if (get_user(mtype, &msgp->mtype))
return -EFAULT;
return do_msgsnd(msqid, mtype, msgp->mtext, msgsz, msgflg);
}
SYSCALL_DEFINE4(msgsnd, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
int, msgflg)
{
return ksys_msgsnd(msqid, msgp, msgsz, msgflg);
}
#ifdef CONFIG_COMPAT
struct compat_msgbuf {
compat_long_t mtype;
char mtext[1];
};
long compat_ksys_msgsnd(int msqid, compat_uptr_t msgp,
compat_ssize_t msgsz, int msgflg)
{
struct compat_msgbuf __user *up = compat_ptr(msgp);
compat_long_t mtype;
if (get_user(mtype, &up->mtype))
return -EFAULT;
return do_msgsnd(msqid, mtype, up->mtext, (ssize_t)msgsz, msgflg);
}
COMPAT_SYSCALL_DEFINE4(msgsnd, int, msqid, compat_uptr_t, msgp,
compat_ssize_t, msgsz, int, msgflg)
{
return compat_ksys_msgsnd(msqid, msgp, msgsz, msgflg);
}
#endif
static inline int convert_mode(long *msgtyp, int msgflg)
{
if (msgflg & MSG_COPY)
return SEARCH_NUMBER;
/*
* find message of correct type.
* msgtyp = 0 => get first.
* msgtyp > 0 => get first message of matching type.
* msgtyp < 0 => get message with least type must be < abs(msgtype).
*/
if (*msgtyp == 0)
return SEARCH_ANY;
if (*msgtyp < 0) {
if (*msgtyp == LONG_MIN) /* -LONG_MIN is undefined */
*msgtyp = LONG_MAX;
else
*msgtyp = -*msgtyp;
return SEARCH_LESSEQUAL;
}
if (msgflg & MSG_EXCEPT)
return SEARCH_NOTEQUAL;
return SEARCH_EQUAL;
}
static long do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz)
{
struct msgbuf __user *msgp = dest;
size_t msgsz;
if (put_user(msg->m_type, &msgp->mtype))
return -EFAULT;
msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz;
if (store_msg(msgp->mtext, msg, msgsz))
return -EFAULT;
return msgsz;
}
#ifdef CONFIG_CHECKPOINT_RESTORE
/*
* This function creates new kernel message structure, large enough to store
* bufsz message bytes.
*/
static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz)
{
struct msg_msg *copy;
/*
* Create dummy message to copy real message to.
*/
copy = load_msg(buf, bufsz);
if (!IS_ERR(copy))
copy->m_ts = bufsz;
return copy;
}
static inline void free_copy(struct msg_msg *copy)
{
if (copy)
free_msg(copy);
}
#else
static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz)
{
return ERR_PTR(-ENOSYS);
}
static inline void free_copy(struct msg_msg *copy)
{
}
#endif
static struct msg_msg *find_msg(struct msg_queue *msq, long *msgtyp, int mode)
{
struct msg_msg *msg, *found = NULL;
long count = 0;
list_for_each_entry(msg, &msq->q_messages, m_list) {
if (testmsg(msg, *msgtyp, mode) &&
!security_msg_queue_msgrcv(&msq->q_perm, msg, current,
*msgtyp, mode)) {
if (mode == SEARCH_LESSEQUAL && msg->m_type != 1) {
*msgtyp = msg->m_type - 1;
found = msg;
} else if (mode == SEARCH_NUMBER) {
if (*msgtyp == count)
return msg;
} else
return msg;
count++;
}
}
return found ?: ERR_PTR(-EAGAIN);
}
static long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp, int msgflg,
long (*msg_handler)(void __user *, struct msg_msg *, size_t))
{
int mode;
struct msg_queue *msq;
struct ipc_namespace *ns;
struct msg_msg *msg, *copy = NULL;
DEFINE_WAKE_Q(wake_q);
ns = current->nsproxy->ipc_ns;
if (msqid < 0 || (long) bufsz < 0)
return -EINVAL;
if (msgflg & MSG_COPY) {
if ((msgflg & MSG_EXCEPT) || !(msgflg & IPC_NOWAIT))
return -EINVAL;
copy = prepare_copy(buf, min_t(size_t, bufsz, ns->msg_ctlmax));
if (IS_ERR(copy))
return PTR_ERR(copy);
}
mode = convert_mode(&msgtyp, msgflg);
rcu_read_lock();
msq = msq_obtain_object_check(ns, msqid);
if (IS_ERR(msq)) {
rcu_read_unlock();
free_copy(copy);
return PTR_ERR(msq);
}
for (;;) {
struct msg_receiver msr_d;
msg = ERR_PTR(-EACCES);
if (ipcperms(ns, &msq->q_perm, S_IRUGO))
goto out_unlock1;
ipc_lock_object(&msq->q_perm);
/* raced with RMID? */
if (!ipc_valid_object(&msq->q_perm)) {
msg = ERR_PTR(-EIDRM);
goto out_unlock0;
}
msg = find_msg(msq, &msgtyp, mode);
if (!IS_ERR(msg)) {
/*
* Found a suitable message.
* Unlink it from the queue.
*/
if ((bufsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) {
msg = ERR_PTR(-E2BIG);
goto out_unlock0;
}
/*
* If we are copying, then do not unlink message and do
* not update queue parameters.
*/
if (msgflg & MSG_COPY) {
msg = copy_msg(msg, copy);
goto out_unlock0;
}
list_del(&msg->m_list);
msq->q_qnum--;
msq->q_rtime = ktime_get_real_seconds();
ipc_update_pid(&msq->q_lrpid, task_tgid(current));
msq->q_cbytes -= msg->m_ts;
percpu_counter_sub_local(&ns->percpu_msg_bytes, msg->m_ts);
percpu_counter_sub_local(&ns->percpu_msg_hdrs, 1);
ss_wakeup(msq, &wake_q, false);
goto out_unlock0;
}
/* No message waiting. Wait for a message */
if (msgflg & IPC_NOWAIT) {
msg = ERR_PTR(-ENOMSG);
goto out_unlock0;
}
list_add_tail(&msr_d.r_list, &msq->q_receivers);
msr_d.r_tsk = current;
msr_d.r_msgtype = msgtyp;
msr_d.r_mode = mode;
if (msgflg & MSG_NOERROR)
msr_d.r_maxsize = INT_MAX;
else
msr_d.r_maxsize = bufsz;
/* memory barrier not require due to ipc_lock_object() */
WRITE_ONCE(msr_d.r_msg, ERR_PTR(-EAGAIN));
/* memory barrier not required, we own ipc_lock_object() */
__set_current_state(TASK_INTERRUPTIBLE);
ipc_unlock_object(&msq->q_perm);
rcu_read_unlock();
schedule();
/*
* Lockless receive, part 1:
* We don't hold a reference to the queue and getting a
* reference would defeat the idea of a lockless operation,
* thus the code relies on rcu to guarantee the existence of
* msq:
* Prior to destruction, expunge_all(-EIRDM) changes r_msg.
* Thus if r_msg is -EAGAIN, then the queue not yet destroyed.
*/
rcu_read_lock();
/*
* Lockless receive, part 2:
* The work in pipelined_send() and expunge_all():
* - Set pointer to message
* - Queue the receiver task for later wakeup
* - Wake up the process after the lock is dropped.
*
* Should the process wake up before this wakeup (due to a
* signal) it will either see the message and continue ...
*/
msg = READ_ONCE(msr_d.r_msg);
if (msg != ERR_PTR(-EAGAIN)) {
/* see MSG_BARRIER for purpose/pairing */
smp_acquire__after_ctrl_dep();
goto out_unlock1;
}
/*
* ... or see -EAGAIN, acquire the lock to check the message
* again.
*/
ipc_lock_object(&msq->q_perm);
msg = READ_ONCE(msr_d.r_msg);
if (msg != ERR_PTR(-EAGAIN))
goto out_unlock0;
list_del(&msr_d.r_list);
if (signal_pending(current)) {
msg = ERR_PTR(-ERESTARTNOHAND);
goto out_unlock0;
}
ipc_unlock_object(&msq->q_perm);
}
out_unlock0:
ipc_unlock_object(&msq->q_perm);
wake_up_q(&wake_q);
out_unlock1:
rcu_read_unlock();
if (IS_ERR(msg)) {
free_copy(copy);
return PTR_ERR(msg);
}
bufsz = msg_handler(buf, msg, bufsz);
free_msg(msg);
return bufsz;
}
long ksys_msgrcv(int msqid, struct msgbuf __user *msgp, size_t msgsz,
long msgtyp, int msgflg)
{
return do_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg, do_msg_fill);
}
SYSCALL_DEFINE5(msgrcv, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
long, msgtyp, int, msgflg)
{
return ksys_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg);
}
#ifdef CONFIG_COMPAT
static long compat_do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz)
{
struct compat_msgbuf __user *msgp = dest;
size_t msgsz;
if (put_user(msg->m_type, &msgp->mtype))
return -EFAULT;
msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz;
if (store_msg(msgp->mtext, msg, msgsz))
return -EFAULT;
return msgsz;
}
long compat_ksys_msgrcv(int msqid, compat_uptr_t msgp, compat_ssize_t msgsz,
compat_long_t msgtyp, int msgflg)
{
return do_msgrcv(msqid, compat_ptr(msgp), (ssize_t)msgsz, (long)msgtyp,
msgflg, compat_do_msg_fill);
}
COMPAT_SYSCALL_DEFINE5(msgrcv, int, msqid, compat_uptr_t, msgp,
compat_ssize_t, msgsz, compat_long_t, msgtyp,
int, msgflg)
{
return compat_ksys_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg);
}
#endif
int msg_init_ns(struct ipc_namespace *ns)
{
int ret;
ns->msg_ctlmax = MSGMAX;
ns->msg_ctlmnb = MSGMNB;
ns->msg_ctlmni = MSGMNI;
ret = percpu_counter_init(&ns->percpu_msg_bytes, 0, GFP_KERNEL);
if (ret)
goto fail_msg_bytes;
ret = percpu_counter_init(&ns->percpu_msg_hdrs, 0, GFP_KERNEL);
if (ret)
goto fail_msg_hdrs;
ipc_init_ids(&ns->ids[IPC_MSG_IDS]);
return 0;
fail_msg_hdrs:
percpu_counter_destroy(&ns->percpu_msg_bytes);
fail_msg_bytes:
return ret;
}
#ifdef CONFIG_IPC_NS
void msg_exit_ns(struct ipc_namespace *ns)
{
free_ipcs(ns, &msg_ids(ns), freeque);
idr_destroy(&ns->ids[IPC_MSG_IDS].ipcs_idr);
rhashtable_destroy(&ns->ids[IPC_MSG_IDS].key_ht);
percpu_counter_destroy(&ns->percpu_msg_bytes);
percpu_counter_destroy(&ns->percpu_msg_hdrs);
}
#endif
#ifdef CONFIG_PROC_FS
static int sysvipc_msg_proc_show(struct seq_file *s, void *it)
{
struct pid_namespace *pid_ns = ipc_seq_pid_ns(s);
struct user_namespace *user_ns = seq_user_ns(s);
struct kern_ipc_perm *ipcp = it;
struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
seq_printf(s,
"%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10llu %10llu %10llu\n",
msq->q_perm.key,
msq->q_perm.id,
msq->q_perm.mode,
msq->q_cbytes,
msq->q_qnum,
pid_nr_ns(msq->q_lspid, pid_ns),
pid_nr_ns(msq->q_lrpid, pid_ns),
from_kuid_munged(user_ns, msq->q_perm.uid),
from_kgid_munged(user_ns, msq->q_perm.gid),
from_kuid_munged(user_ns, msq->q_perm.cuid),
from_kgid_munged(user_ns, msq->q_perm.cgid),
msq->q_stime,
msq->q_rtime,
msq->q_ctime);
return 0;
}
#endif
void __init msg_init(void)
{
msg_init_ns(&init_ipc_ns);
ipc_init_proc_interface("sysvipc/msg",
" key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n",
IPC_MSG_IDS, sysvipc_msg_proc_show);
}
| linux-master | ipc/msg.c |
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* linux/ipc/msgutil.c
* Copyright (C) 1999, 2004 Manfred Spraul
*/
#include <linux/spinlock.h>
#include <linux/init.h>
#include <linux/security.h>
#include <linux/slab.h>
#include <linux/ipc.h>
#include <linux/msg.h>
#include <linux/ipc_namespace.h>
#include <linux/utsname.h>
#include <linux/proc_ns.h>
#include <linux/uaccess.h>
#include <linux/sched.h>
#include "util.h"
DEFINE_SPINLOCK(mq_lock);
/*
* The next 2 defines are here bc this is the only file
* compiled when either CONFIG_SYSVIPC and CONFIG_POSIX_MQUEUE
* and not CONFIG_IPC_NS.
*/
struct ipc_namespace init_ipc_ns = {
.ns.count = REFCOUNT_INIT(1),
.user_ns = &init_user_ns,
.ns.inum = PROC_IPC_INIT_INO,
#ifdef CONFIG_IPC_NS
.ns.ops = &ipcns_operations,
#endif
};
struct msg_msgseg {
struct msg_msgseg *next;
/* the next part of the message follows immediately */
};
#define DATALEN_MSG ((size_t)PAGE_SIZE-sizeof(struct msg_msg))
#define DATALEN_SEG ((size_t)PAGE_SIZE-sizeof(struct msg_msgseg))
static struct msg_msg *alloc_msg(size_t len)
{
struct msg_msg *msg;
struct msg_msgseg **pseg;
size_t alen;
alen = min(len, DATALEN_MSG);
msg = kmalloc(sizeof(*msg) + alen, GFP_KERNEL_ACCOUNT);
if (msg == NULL)
return NULL;
msg->next = NULL;
msg->security = NULL;
len -= alen;
pseg = &msg->next;
while (len > 0) {
struct msg_msgseg *seg;
cond_resched();
alen = min(len, DATALEN_SEG);
seg = kmalloc(sizeof(*seg) + alen, GFP_KERNEL_ACCOUNT);
if (seg == NULL)
goto out_err;
*pseg = seg;
seg->next = NULL;
pseg = &seg->next;
len -= alen;
}
return msg;
out_err:
free_msg(msg);
return NULL;
}
struct msg_msg *load_msg(const void __user *src, size_t len)
{
struct msg_msg *msg;
struct msg_msgseg *seg;
int err = -EFAULT;
size_t alen;
msg = alloc_msg(len);
if (msg == NULL)
return ERR_PTR(-ENOMEM);
alen = min(len, DATALEN_MSG);
if (copy_from_user(msg + 1, src, alen))
goto out_err;
for (seg = msg->next; seg != NULL; seg = seg->next) {
len -= alen;
src = (char __user *)src + alen;
alen = min(len, DATALEN_SEG);
if (copy_from_user(seg + 1, src, alen))
goto out_err;
}
err = security_msg_msg_alloc(msg);
if (err)
goto out_err;
return msg;
out_err:
free_msg(msg);
return ERR_PTR(err);
}
#ifdef CONFIG_CHECKPOINT_RESTORE
struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst)
{
struct msg_msgseg *dst_pseg, *src_pseg;
size_t len = src->m_ts;
size_t alen;
if (src->m_ts > dst->m_ts)
return ERR_PTR(-EINVAL);
alen = min(len, DATALEN_MSG);
memcpy(dst + 1, src + 1, alen);
for (dst_pseg = dst->next, src_pseg = src->next;
src_pseg != NULL;
dst_pseg = dst_pseg->next, src_pseg = src_pseg->next) {
len -= alen;
alen = min(len, DATALEN_SEG);
memcpy(dst_pseg + 1, src_pseg + 1, alen);
}
dst->m_type = src->m_type;
dst->m_ts = src->m_ts;
return dst;
}
#else
struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst)
{
return ERR_PTR(-ENOSYS);
}
#endif
int store_msg(void __user *dest, struct msg_msg *msg, size_t len)
{
size_t alen;
struct msg_msgseg *seg;
alen = min(len, DATALEN_MSG);
if (copy_to_user(dest, msg + 1, alen))
return -1;
for (seg = msg->next; seg != NULL; seg = seg->next) {
len -= alen;
dest = (char __user *)dest + alen;
alen = min(len, DATALEN_SEG);
if (copy_to_user(dest, seg + 1, alen))
return -1;
}
return 0;
}
void free_msg(struct msg_msg *msg)
{
struct msg_msgseg *seg;
security_msg_msg_free(msg);
seg = msg->next;
kfree(msg);
while (seg != NULL) {
struct msg_msgseg *tmp = seg->next;
cond_resched();
kfree(seg);
seg = tmp;
}
}
| linux-master | ipc/msgutil.c |
// SPDX-License-Identifier: GPL-2.0
/*
* 32 bit compatibility code for System V IPC
*
* Copyright (C) 1997,1998 Jakub Jelinek ([email protected])
* Copyright (C) 1997 David S. Miller ([email protected])
* Copyright (C) 1999 Arun Sharma <[email protected]>
* Copyright (C) 2000 VA Linux Co
* Copyright (C) 2000 Don Dugger <[email protected]>
* Copyright (C) 2000 Hewlett-Packard Co.
* Copyright (C) 2000 David Mosberger-Tang <[email protected]>
* Copyright (C) 2000 Gerhard Tonn ([email protected])
* Copyright (C) 2000-2002 Andi Kleen, SuSE Labs (x86-64 port)
* Copyright (C) 2000 Silicon Graphics, Inc.
* Copyright (C) 2001 IBM
* Copyright (C) 2004 IBM Deutschland Entwicklung GmbH, IBM Corporation
* Copyright (C) 2004 Arnd Bergmann ([email protected])
*
* This code is collected from the versions for sparc64, mips64, s390x, ia64,
* ppc64 and x86_64, all of which are based on the original sparc64 version
* by Jakub Jelinek.
*
*/
#include <linux/compat.h>
#include <linux/errno.h>
#include <linux/highuid.h>
#include <linux/init.h>
#include <linux/msg.h>
#include <linux/shm.h>
#include <linux/syscalls.h>
#include <linux/ptrace.h>
#include <linux/mutex.h>
#include <linux/uaccess.h>
#include "util.h"
int get_compat_ipc64_perm(struct ipc64_perm *to,
struct compat_ipc64_perm __user *from)
{
struct compat_ipc64_perm v;
if (copy_from_user(&v, from, sizeof(v)))
return -EFAULT;
to->uid = v.uid;
to->gid = v.gid;
to->mode = v.mode;
return 0;
}
int get_compat_ipc_perm(struct ipc64_perm *to,
struct compat_ipc_perm __user *from)
{
struct compat_ipc_perm v;
if (copy_from_user(&v, from, sizeof(v)))
return -EFAULT;
to->uid = v.uid;
to->gid = v.gid;
to->mode = v.mode;
return 0;
}
void to_compat_ipc64_perm(struct compat_ipc64_perm *to, struct ipc64_perm *from)
{
to->key = from->key;
to->uid = from->uid;
to->gid = from->gid;
to->cuid = from->cuid;
to->cgid = from->cgid;
to->mode = from->mode;
to->seq = from->seq;
}
void to_compat_ipc_perm(struct compat_ipc_perm *to, struct ipc64_perm *from)
{
to->key = from->key;
SET_UID(to->uid, from->uid);
SET_GID(to->gid, from->gid);
SET_UID(to->cuid, from->cuid);
SET_GID(to->cgid, from->cgid);
to->mode = from->mode;
to->seq = from->seq;
}
| linux-master | ipc/compat.c |
// SPDX-License-Identifier: GPL-2.0
/*
* linux/ipc/util.c
* Copyright (C) 1992 Krishna Balasubramanian
*
* Sep 1997 - Call suser() last after "normal" permission checks so we
* get BSD style process accounting right.
* Occurs in several places in the IPC code.
* Chris Evans, <[email protected]>
* Nov 1999 - ipc helper functions, unified SMP locking
* Manfred Spraul <[email protected]>
* Oct 2002 - One lock per IPC id. RCU ipc_free for lock-free grow_ary().
* Mingming Cao <[email protected]>
* Mar 2006 - support for audit of ipc object properties
* Dustin Kirkland <[email protected]>
* Jun 2006 - namespaces ssupport
* OpenVZ, SWsoft Inc.
* Pavel Emelianov <[email protected]>
*
* General sysv ipc locking scheme:
* rcu_read_lock()
* obtain the ipc object (kern_ipc_perm) by looking up the id in an idr
* tree.
* - perform initial checks (capabilities, auditing and permission,
* etc).
* - perform read-only operations, such as INFO command, that
* do not demand atomicity
* acquire the ipc lock (kern_ipc_perm.lock) through
* ipc_lock_object()
* - perform read-only operations that demand atomicity,
* such as STAT command.
* - perform data updates, such as SET, RMID commands and
* mechanism-specific operations (semop/semtimedop,
* msgsnd/msgrcv, shmat/shmdt).
* drop the ipc lock, through ipc_unlock_object().
* rcu_read_unlock()
*
* The ids->rwsem must be taken when:
* - creating, removing and iterating the existing entries in ipc
* identifier sets.
* - iterating through files under /proc/sysvipc/
*
* Note that sems have a special fast path that avoids kern_ipc_perm.lock -
* see sem_lock().
*/
#include <linux/mm.h>
#include <linux/shm.h>
#include <linux/init.h>
#include <linux/msg.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/notifier.h>
#include <linux/capability.h>
#include <linux/highuid.h>
#include <linux/security.h>
#include <linux/rcupdate.h>
#include <linux/workqueue.h>
#include <linux/seq_file.h>
#include <linux/proc_fs.h>
#include <linux/audit.h>
#include <linux/nsproxy.h>
#include <linux/rwsem.h>
#include <linux/memory.h>
#include <linux/ipc_namespace.h>
#include <linux/rhashtable.h>
#include <linux/log2.h>
#include <asm/unistd.h>
#include "util.h"
struct ipc_proc_iface {
const char *path;
const char *header;
int ids;
int (*show)(struct seq_file *, void *);
};
/**
* ipc_init - initialise ipc subsystem
*
* The various sysv ipc resources (semaphores, messages and shared
* memory) are initialised.
*
* A callback routine is registered into the memory hotplug notifier
* chain: since msgmni scales to lowmem this callback routine will be
* called upon successful memory add / remove to recompute msmgni.
*/
static int __init ipc_init(void)
{
proc_mkdir("sysvipc", NULL);
sem_init();
msg_init();
shm_init();
return 0;
}
device_initcall(ipc_init);
static const struct rhashtable_params ipc_kht_params = {
.head_offset = offsetof(struct kern_ipc_perm, khtnode),
.key_offset = offsetof(struct kern_ipc_perm, key),
.key_len = sizeof_field(struct kern_ipc_perm, key),
.automatic_shrinking = true,
};
/**
* ipc_init_ids - initialise ipc identifiers
* @ids: ipc identifier set
*
* Set up the sequence range to use for the ipc identifier range (limited
* below ipc_mni) then initialise the keys hashtable and ids idr.
*/
void ipc_init_ids(struct ipc_ids *ids)
{
ids->in_use = 0;
ids->seq = 0;
init_rwsem(&ids->rwsem);
rhashtable_init(&ids->key_ht, &ipc_kht_params);
idr_init(&ids->ipcs_idr);
ids->max_idx = -1;
ids->last_idx = -1;
#ifdef CONFIG_CHECKPOINT_RESTORE
ids->next_id = -1;
#endif
}
#ifdef CONFIG_PROC_FS
static const struct proc_ops sysvipc_proc_ops;
/**
* ipc_init_proc_interface - create a proc interface for sysipc types using a seq_file interface.
* @path: Path in procfs
* @header: Banner to be printed at the beginning of the file.
* @ids: ipc id table to iterate.
* @show: show routine.
*/
void __init ipc_init_proc_interface(const char *path, const char *header,
int ids, int (*show)(struct seq_file *, void *))
{
struct proc_dir_entry *pde;
struct ipc_proc_iface *iface;
iface = kmalloc(sizeof(*iface), GFP_KERNEL);
if (!iface)
return;
iface->path = path;
iface->header = header;
iface->ids = ids;
iface->show = show;
pde = proc_create_data(path,
S_IRUGO, /* world readable */
NULL, /* parent dir */
&sysvipc_proc_ops,
iface);
if (!pde)
kfree(iface);
}
#endif
/**
* ipc_findkey - find a key in an ipc identifier set
* @ids: ipc identifier set
* @key: key to find
*
* Returns the locked pointer to the ipc structure if found or NULL
* otherwise. If key is found ipc points to the owning ipc structure
*
* Called with writer ipc_ids.rwsem held.
*/
static struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key)
{
struct kern_ipc_perm *ipcp;
ipcp = rhashtable_lookup_fast(&ids->key_ht, &key,
ipc_kht_params);
if (!ipcp)
return NULL;
rcu_read_lock();
ipc_lock_object(ipcp);
return ipcp;
}
/*
* Insert new IPC object into idr tree, and set sequence number and id
* in the correct order.
* Especially:
* - the sequence number must be set before inserting the object into the idr,
* because the sequence number is accessed without a lock.
* - the id can/must be set after inserting the object into the idr.
* All accesses must be done after getting kern_ipc_perm.lock.
*
* The caller must own kern_ipc_perm.lock.of the new object.
* On error, the function returns a (negative) error code.
*
* To conserve sequence number space, especially with extended ipc_mni,
* the sequence number is incremented only when the returned ID is less than
* the last one.
*/
static inline int ipc_idr_alloc(struct ipc_ids *ids, struct kern_ipc_perm *new)
{
int idx, next_id = -1;
#ifdef CONFIG_CHECKPOINT_RESTORE
next_id = ids->next_id;
ids->next_id = -1;
#endif
/*
* As soon as a new object is inserted into the idr,
* ipc_obtain_object_idr() or ipc_obtain_object_check() can find it,
* and the lockless preparations for ipc operations can start.
* This means especially: permission checks, audit calls, allocation
* of undo structures, ...
*
* Thus the object must be fully initialized, and if something fails,
* then the full tear-down sequence must be followed.
* (i.e.: set new->deleted, reduce refcount, call_rcu())
*/
if (next_id < 0) { /* !CHECKPOINT_RESTORE or next_id is unset */
int max_idx;
max_idx = max(ids->in_use*3/2, ipc_min_cycle);
max_idx = min(max_idx, ipc_mni);
/* allocate the idx, with a NULL struct kern_ipc_perm */
idx = idr_alloc_cyclic(&ids->ipcs_idr, NULL, 0, max_idx,
GFP_NOWAIT);
if (idx >= 0) {
/*
* idx got allocated successfully.
* Now calculate the sequence number and set the
* pointer for real.
*/
if (idx <= ids->last_idx) {
ids->seq++;
if (ids->seq >= ipcid_seq_max())
ids->seq = 0;
}
ids->last_idx = idx;
new->seq = ids->seq;
/* no need for smp_wmb(), this is done
* inside idr_replace, as part of
* rcu_assign_pointer
*/
idr_replace(&ids->ipcs_idr, new, idx);
}
} else {
new->seq = ipcid_to_seqx(next_id);
idx = idr_alloc(&ids->ipcs_idr, new, ipcid_to_idx(next_id),
0, GFP_NOWAIT);
}
if (idx >= 0)
new->id = (new->seq << ipcmni_seq_shift()) + idx;
return idx;
}
/**
* ipc_addid - add an ipc identifier
* @ids: ipc identifier set
* @new: new ipc permission set
* @limit: limit for the number of used ids
*
* Add an entry 'new' to the ipc ids idr. The permissions object is
* initialised and the first free entry is set up and the index assigned
* is returned. The 'new' entry is returned in a locked state on success.
*
* On failure the entry is not locked and a negative err-code is returned.
* The caller must use ipc_rcu_putref() to free the identifier.
*
* Called with writer ipc_ids.rwsem held.
*/
int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int limit)
{
kuid_t euid;
kgid_t egid;
int idx, err;
/* 1) Initialize the refcount so that ipc_rcu_putref works */
refcount_set(&new->refcount, 1);
if (limit > ipc_mni)
limit = ipc_mni;
if (ids->in_use >= limit)
return -ENOSPC;
idr_preload(GFP_KERNEL);
spin_lock_init(&new->lock);
rcu_read_lock();
spin_lock(&new->lock);
current_euid_egid(&euid, &egid);
new->cuid = new->uid = euid;
new->gid = new->cgid = egid;
new->deleted = false;
idx = ipc_idr_alloc(ids, new);
idr_preload_end();
if (idx >= 0 && new->key != IPC_PRIVATE) {
err = rhashtable_insert_fast(&ids->key_ht, &new->khtnode,
ipc_kht_params);
if (err < 0) {
idr_remove(&ids->ipcs_idr, idx);
idx = err;
}
}
if (idx < 0) {
new->deleted = true;
spin_unlock(&new->lock);
rcu_read_unlock();
return idx;
}
ids->in_use++;
if (idx > ids->max_idx)
ids->max_idx = idx;
return idx;
}
/**
* ipcget_new - create a new ipc object
* @ns: ipc namespace
* @ids: ipc identifier set
* @ops: the actual creation routine to call
* @params: its parameters
*
* This routine is called by sys_msgget, sys_semget() and sys_shmget()
* when the key is IPC_PRIVATE.
*/
static int ipcget_new(struct ipc_namespace *ns, struct ipc_ids *ids,
const struct ipc_ops *ops, struct ipc_params *params)
{
int err;
down_write(&ids->rwsem);
err = ops->getnew(ns, params);
up_write(&ids->rwsem);
return err;
}
/**
* ipc_check_perms - check security and permissions for an ipc object
* @ns: ipc namespace
* @ipcp: ipc permission set
* @ops: the actual security routine to call
* @params: its parameters
*
* This routine is called by sys_msgget(), sys_semget() and sys_shmget()
* when the key is not IPC_PRIVATE and that key already exists in the
* ds IDR.
*
* On success, the ipc id is returned.
*
* It is called with ipc_ids.rwsem and ipcp->lock held.
*/
static int ipc_check_perms(struct ipc_namespace *ns,
struct kern_ipc_perm *ipcp,
const struct ipc_ops *ops,
struct ipc_params *params)
{
int err;
if (ipcperms(ns, ipcp, params->flg))
err = -EACCES;
else {
err = ops->associate(ipcp, params->flg);
if (!err)
err = ipcp->id;
}
return err;
}
/**
* ipcget_public - get an ipc object or create a new one
* @ns: ipc namespace
* @ids: ipc identifier set
* @ops: the actual creation routine to call
* @params: its parameters
*
* This routine is called by sys_msgget, sys_semget() and sys_shmget()
* when the key is not IPC_PRIVATE.
* It adds a new entry if the key is not found and does some permission
* / security checkings if the key is found.
*
* On success, the ipc id is returned.
*/
static int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids,
const struct ipc_ops *ops, struct ipc_params *params)
{
struct kern_ipc_perm *ipcp;
int flg = params->flg;
int err;
/*
* Take the lock as a writer since we are potentially going to add
* a new entry + read locks are not "upgradable"
*/
down_write(&ids->rwsem);
ipcp = ipc_findkey(ids, params->key);
if (ipcp == NULL) {
/* key not used */
if (!(flg & IPC_CREAT))
err = -ENOENT;
else
err = ops->getnew(ns, params);
} else {
/* ipc object has been locked by ipc_findkey() */
if (flg & IPC_CREAT && flg & IPC_EXCL)
err = -EEXIST;
else {
err = 0;
if (ops->more_checks)
err = ops->more_checks(ipcp, params);
if (!err)
/*
* ipc_check_perms returns the IPC id on
* success
*/
err = ipc_check_perms(ns, ipcp, ops, params);
}
ipc_unlock(ipcp);
}
up_write(&ids->rwsem);
return err;
}
/**
* ipc_kht_remove - remove an ipc from the key hashtable
* @ids: ipc identifier set
* @ipcp: ipc perm structure containing the key to remove
*
* ipc_ids.rwsem (as a writer) and the spinlock for this ID are held
* before this function is called, and remain locked on the exit.
*/
static void ipc_kht_remove(struct ipc_ids *ids, struct kern_ipc_perm *ipcp)
{
if (ipcp->key != IPC_PRIVATE)
WARN_ON_ONCE(rhashtable_remove_fast(&ids->key_ht, &ipcp->khtnode,
ipc_kht_params));
}
/**
* ipc_search_maxidx - search for the highest assigned index
* @ids: ipc identifier set
* @limit: known upper limit for highest assigned index
*
* The function determines the highest assigned index in @ids. It is intended
* to be called when ids->max_idx needs to be updated.
* Updating ids->max_idx is necessary when the current highest index ipc
* object is deleted.
* If no ipc object is allocated, then -1 is returned.
*
* ipc_ids.rwsem needs to be held by the caller.
*/
static int ipc_search_maxidx(struct ipc_ids *ids, int limit)
{
int tmpidx;
int i;
int retval;
i = ilog2(limit+1);
retval = 0;
for (; i >= 0; i--) {
tmpidx = retval | (1<<i);
/*
* "0" is a possible index value, thus search using
* e.g. 15,7,3,1,0 instead of 16,8,4,2,1.
*/
tmpidx = tmpidx-1;
if (idr_get_next(&ids->ipcs_idr, &tmpidx))
retval |= (1<<i);
}
return retval - 1;
}
/**
* ipc_rmid - remove an ipc identifier
* @ids: ipc identifier set
* @ipcp: ipc perm structure containing the identifier to remove
*
* ipc_ids.rwsem (as a writer) and the spinlock for this ID are held
* before this function is called, and remain locked on the exit.
*/
void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp)
{
int idx = ipcid_to_idx(ipcp->id);
WARN_ON_ONCE(idr_remove(&ids->ipcs_idr, idx) != ipcp);
ipc_kht_remove(ids, ipcp);
ids->in_use--;
ipcp->deleted = true;
if (unlikely(idx == ids->max_idx)) {
idx = ids->max_idx-1;
if (idx >= 0)
idx = ipc_search_maxidx(ids, idx);
ids->max_idx = idx;
}
}
/**
* ipc_set_key_private - switch the key of an existing ipc to IPC_PRIVATE
* @ids: ipc identifier set
* @ipcp: ipc perm structure containing the key to modify
*
* ipc_ids.rwsem (as a writer) and the spinlock for this ID are held
* before this function is called, and remain locked on the exit.
*/
void ipc_set_key_private(struct ipc_ids *ids, struct kern_ipc_perm *ipcp)
{
ipc_kht_remove(ids, ipcp);
ipcp->key = IPC_PRIVATE;
}
bool ipc_rcu_getref(struct kern_ipc_perm *ptr)
{
return refcount_inc_not_zero(&ptr->refcount);
}
void ipc_rcu_putref(struct kern_ipc_perm *ptr,
void (*func)(struct rcu_head *head))
{
if (!refcount_dec_and_test(&ptr->refcount))
return;
call_rcu(&ptr->rcu, func);
}
/**
* ipcperms - check ipc permissions
* @ns: ipc namespace
* @ipcp: ipc permission set
* @flag: desired permission set
*
* Check user, group, other permissions for access
* to ipc resources. return 0 if allowed
*
* @flag will most probably be 0 or ``S_...UGO`` from <linux/stat.h>
*/
int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flag)
{
kuid_t euid = current_euid();
int requested_mode, granted_mode;
audit_ipc_obj(ipcp);
requested_mode = (flag >> 6) | (flag >> 3) | flag;
granted_mode = ipcp->mode;
if (uid_eq(euid, ipcp->cuid) ||
uid_eq(euid, ipcp->uid))
granted_mode >>= 6;
else if (in_group_p(ipcp->cgid) || in_group_p(ipcp->gid))
granted_mode >>= 3;
/* is there some bit set in requested_mode but not in granted_mode? */
if ((requested_mode & ~granted_mode & 0007) &&
!ns_capable(ns->user_ns, CAP_IPC_OWNER))
return -1;
return security_ipc_permission(ipcp, flag);
}
/*
* Functions to convert between the kern_ipc_perm structure and the
* old/new ipc_perm structures
*/
/**
* kernel_to_ipc64_perm - convert kernel ipc permissions to user
* @in: kernel permissions
* @out: new style ipc permissions
*
* Turn the kernel object @in into a set of permissions descriptions
* for returning to userspace (@out).
*/
void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out)
{
out->key = in->key;
out->uid = from_kuid_munged(current_user_ns(), in->uid);
out->gid = from_kgid_munged(current_user_ns(), in->gid);
out->cuid = from_kuid_munged(current_user_ns(), in->cuid);
out->cgid = from_kgid_munged(current_user_ns(), in->cgid);
out->mode = in->mode;
out->seq = in->seq;
}
/**
* ipc64_perm_to_ipc_perm - convert new ipc permissions to old
* @in: new style ipc permissions
* @out: old style ipc permissions
*
* Turn the new style permissions object @in into a compatibility
* object and store it into the @out pointer.
*/
void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out)
{
out->key = in->key;
SET_UID(out->uid, in->uid);
SET_GID(out->gid, in->gid);
SET_UID(out->cuid, in->cuid);
SET_GID(out->cgid, in->cgid);
out->mode = in->mode;
out->seq = in->seq;
}
/**
* ipc_obtain_object_idr
* @ids: ipc identifier set
* @id: ipc id to look for
*
* Look for an id in the ipc ids idr and return associated ipc object.
*
* Call inside the RCU critical section.
* The ipc object is *not* locked on exit.
*/
struct kern_ipc_perm *ipc_obtain_object_idr(struct ipc_ids *ids, int id)
{
struct kern_ipc_perm *out;
int idx = ipcid_to_idx(id);
out = idr_find(&ids->ipcs_idr, idx);
if (!out)
return ERR_PTR(-EINVAL);
return out;
}
/**
* ipc_obtain_object_check
* @ids: ipc identifier set
* @id: ipc id to look for
*
* Similar to ipc_obtain_object_idr() but also checks the ipc object
* sequence number.
*
* Call inside the RCU critical section.
* The ipc object is *not* locked on exit.
*/
struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id)
{
struct kern_ipc_perm *out = ipc_obtain_object_idr(ids, id);
if (IS_ERR(out))
goto out;
if (ipc_checkid(out, id))
return ERR_PTR(-EINVAL);
out:
return out;
}
/**
* ipcget - Common sys_*get() code
* @ns: namespace
* @ids: ipc identifier set
* @ops: operations to be called on ipc object creation, permission checks
* and further checks
* @params: the parameters needed by the previous operations.
*
* Common routine called by sys_msgget(), sys_semget() and sys_shmget().
*/
int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
const struct ipc_ops *ops, struct ipc_params *params)
{
if (params->key == IPC_PRIVATE)
return ipcget_new(ns, ids, ops, params);
else
return ipcget_public(ns, ids, ops, params);
}
/**
* ipc_update_perm - update the permissions of an ipc object
* @in: the permission given as input.
* @out: the permission of the ipc to set.
*/
int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out)
{
kuid_t uid = make_kuid(current_user_ns(), in->uid);
kgid_t gid = make_kgid(current_user_ns(), in->gid);
if (!uid_valid(uid) || !gid_valid(gid))
return -EINVAL;
out->uid = uid;
out->gid = gid;
out->mode = (out->mode & ~S_IRWXUGO)
| (in->mode & S_IRWXUGO);
return 0;
}
/**
* ipcctl_obtain_check - retrieve an ipc object and check permissions
* @ns: ipc namespace
* @ids: the table of ids where to look for the ipc
* @id: the id of the ipc to retrieve
* @cmd: the cmd to check
* @perm: the permission to set
* @extra_perm: one extra permission parameter used by msq
*
* This function does some common audit and permissions check for some IPC_XXX
* cmd and is called from semctl_down, shmctl_down and msgctl_down.
*
* It:
* - retrieves the ipc object with the given id in the given table.
* - performs some audit and permission check, depending on the given cmd
* - returns a pointer to the ipc object or otherwise, the corresponding
* error.
*
* Call holding the both the rwsem and the rcu read lock.
*/
struct kern_ipc_perm *ipcctl_obtain_check(struct ipc_namespace *ns,
struct ipc_ids *ids, int id, int cmd,
struct ipc64_perm *perm, int extra_perm)
{
kuid_t euid;
int err = -EPERM;
struct kern_ipc_perm *ipcp;
ipcp = ipc_obtain_object_check(ids, id);
if (IS_ERR(ipcp)) {
err = PTR_ERR(ipcp);
goto err;
}
audit_ipc_obj(ipcp);
if (cmd == IPC_SET)
audit_ipc_set_perm(extra_perm, perm->uid,
perm->gid, perm->mode);
euid = current_euid();
if (uid_eq(euid, ipcp->cuid) || uid_eq(euid, ipcp->uid) ||
ns_capable(ns->user_ns, CAP_SYS_ADMIN))
return ipcp; /* successful lookup */
err:
return ERR_PTR(err);
}
#ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
/**
* ipc_parse_version - ipc call version
* @cmd: pointer to command
*
* Return IPC_64 for new style IPC and IPC_OLD for old style IPC.
* The @cmd value is turned from an encoding command and version into
* just the command code.
*/
int ipc_parse_version(int *cmd)
{
if (*cmd & IPC_64) {
*cmd ^= IPC_64;
return IPC_64;
} else {
return IPC_OLD;
}
}
#endif /* CONFIG_ARCH_WANT_IPC_PARSE_VERSION */
#ifdef CONFIG_PROC_FS
struct ipc_proc_iter {
struct ipc_namespace *ns;
struct pid_namespace *pid_ns;
struct ipc_proc_iface *iface;
};
struct pid_namespace *ipc_seq_pid_ns(struct seq_file *s)
{
struct ipc_proc_iter *iter = s->private;
return iter->pid_ns;
}
/**
* sysvipc_find_ipc - Find and lock the ipc structure based on seq pos
* @ids: ipc identifier set
* @pos: expected position
*
* The function finds an ipc structure, based on the sequence file
* position @pos. If there is no ipc structure at position @pos, then
* the successor is selected.
* If a structure is found, then it is locked (both rcu_read_lock() and
* ipc_lock_object()) and @pos is set to the position needed to locate
* the found ipc structure.
* If nothing is found (i.e. EOF), @pos is not modified.
*
* The function returns the found ipc structure, or NULL at EOF.
*/
static struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t *pos)
{
int tmpidx;
struct kern_ipc_perm *ipc;
/* convert from position to idr index -> "-1" */
tmpidx = *pos - 1;
ipc = idr_get_next(&ids->ipcs_idr, &tmpidx);
if (ipc != NULL) {
rcu_read_lock();
ipc_lock_object(ipc);
/* convert from idr index to position -> "+1" */
*pos = tmpidx + 1;
}
return ipc;
}
static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos)
{
struct ipc_proc_iter *iter = s->private;
struct ipc_proc_iface *iface = iter->iface;
struct kern_ipc_perm *ipc = it;
/* If we had an ipc id locked before, unlock it */
if (ipc && ipc != SEQ_START_TOKEN)
ipc_unlock(ipc);
/* Next -> search for *pos+1 */
(*pos)++;
return sysvipc_find_ipc(&iter->ns->ids[iface->ids], pos);
}
/*
* File positions: pos 0 -> header, pos n -> ipc idx = n - 1.
* SeqFile iterator: iterator value locked ipc pointer or SEQ_TOKEN_START.
*/
static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos)
{
struct ipc_proc_iter *iter = s->private;
struct ipc_proc_iface *iface = iter->iface;
struct ipc_ids *ids;
ids = &iter->ns->ids[iface->ids];
/*
* Take the lock - this will be released by the corresponding
* call to stop().
*/
down_read(&ids->rwsem);
/* pos < 0 is invalid */
if (*pos < 0)
return NULL;
/* pos == 0 means header */
if (*pos == 0)
return SEQ_START_TOKEN;
/* Otherwise return the correct ipc structure */
return sysvipc_find_ipc(ids, pos);
}
static void sysvipc_proc_stop(struct seq_file *s, void *it)
{
struct kern_ipc_perm *ipc = it;
struct ipc_proc_iter *iter = s->private;
struct ipc_proc_iface *iface = iter->iface;
struct ipc_ids *ids;
/* If we had a locked structure, release it */
if (ipc && ipc != SEQ_START_TOKEN)
ipc_unlock(ipc);
ids = &iter->ns->ids[iface->ids];
/* Release the lock we took in start() */
up_read(&ids->rwsem);
}
static int sysvipc_proc_show(struct seq_file *s, void *it)
{
struct ipc_proc_iter *iter = s->private;
struct ipc_proc_iface *iface = iter->iface;
if (it == SEQ_START_TOKEN) {
seq_puts(s, iface->header);
return 0;
}
return iface->show(s, it);
}
static const struct seq_operations sysvipc_proc_seqops = {
.start = sysvipc_proc_start,
.stop = sysvipc_proc_stop,
.next = sysvipc_proc_next,
.show = sysvipc_proc_show,
};
static int sysvipc_proc_open(struct inode *inode, struct file *file)
{
struct ipc_proc_iter *iter;
iter = __seq_open_private(file, &sysvipc_proc_seqops, sizeof(*iter));
if (!iter)
return -ENOMEM;
iter->iface = pde_data(inode);
iter->ns = get_ipc_ns(current->nsproxy->ipc_ns);
iter->pid_ns = get_pid_ns(task_active_pid_ns(current));
return 0;
}
static int sysvipc_proc_release(struct inode *inode, struct file *file)
{
struct seq_file *seq = file->private_data;
struct ipc_proc_iter *iter = seq->private;
put_ipc_ns(iter->ns);
put_pid_ns(iter->pid_ns);
return seq_release_private(inode, file);
}
static const struct proc_ops sysvipc_proc_ops = {
.proc_flags = PROC_ENTRY_PERMANENT,
.proc_open = sysvipc_proc_open,
.proc_read = seq_read,
.proc_lseek = seq_lseek,
.proc_release = sysvipc_proc_release,
};
#endif /* CONFIG_PROC_FS */
| linux-master | ipc/util.c |
// SPDX-License-Identifier: GPL-2.0
/*
* linux/ipc/shm.c
* Copyright (C) 1992, 1993 Krishna Balasubramanian
* Many improvements/fixes by Bruno Haible.
* Replaced `struct shm_desc' by `struct vm_area_struct', July 1994.
* Fixed the shm swap deallocation (shm_unuse()), August 1998 Andrea Arcangeli.
*
* /proc/sysvipc/shm support (c) 1999 Dragos Acostachioaie <[email protected]>
* BIGMEM support, Andrea Arcangeli <[email protected]>
* SMP thread shm, Jean-Luc Boyard <[email protected]>
* HIGHMEM support, Ingo Molnar <[email protected]>
* Make shmmax, shmall, shmmni sysctl'able, Christoph Rohland <[email protected]>
* Shared /dev/zero support, Kanoj Sarcar <[email protected]>
* Move the mm functionality over to mm/shmem.c, Christoph Rohland <[email protected]>
*
* support for audit of ipc object properties and permission changes
* Dustin Kirkland <[email protected]>
*
* namespaces support
* OpenVZ, SWsoft Inc.
* Pavel Emelianov <[email protected]>
*
* Better ipc lock (kern_ipc_perm.lock) handling
* Davidlohr Bueso <[email protected]>, June 2013.
*/
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/hugetlb.h>
#include <linux/shm.h>
#include <linux/init.h>
#include <linux/file.h>
#include <linux/mman.h>
#include <linux/shmem_fs.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/audit.h>
#include <linux/capability.h>
#include <linux/ptrace.h>
#include <linux/seq_file.h>
#include <linux/rwsem.h>
#include <linux/nsproxy.h>
#include <linux/mount.h>
#include <linux/ipc_namespace.h>
#include <linux/rhashtable.h>
#include <linux/uaccess.h>
#include "util.h"
struct shmid_kernel /* private to the kernel */
{
struct kern_ipc_perm shm_perm;
struct file *shm_file;
unsigned long shm_nattch;
unsigned long shm_segsz;
time64_t shm_atim;
time64_t shm_dtim;
time64_t shm_ctim;
struct pid *shm_cprid;
struct pid *shm_lprid;
struct ucounts *mlock_ucounts;
/*
* The task created the shm object, for
* task_lock(shp->shm_creator)
*/
struct task_struct *shm_creator;
/*
* List by creator. task_lock(->shm_creator) required for read/write.
* If list_empty(), then the creator is dead already.
*/
struct list_head shm_clist;
struct ipc_namespace *ns;
} __randomize_layout;
/* shm_mode upper byte flags */
#define SHM_DEST 01000 /* segment will be destroyed on last detach */
#define SHM_LOCKED 02000 /* segment will not be swapped */
struct shm_file_data {
int id;
struct ipc_namespace *ns;
struct file *file;
const struct vm_operations_struct *vm_ops;
};
#define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
static const struct file_operations shm_file_operations;
static const struct vm_operations_struct shm_vm_ops;
#define shm_ids(ns) ((ns)->ids[IPC_SHM_IDS])
#define shm_unlock(shp) \
ipc_unlock(&(shp)->shm_perm)
static int newseg(struct ipc_namespace *, struct ipc_params *);
static void shm_open(struct vm_area_struct *vma);
static void shm_close(struct vm_area_struct *vma);
static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp);
#ifdef CONFIG_PROC_FS
static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
#endif
void shm_init_ns(struct ipc_namespace *ns)
{
ns->shm_ctlmax = SHMMAX;
ns->shm_ctlall = SHMALL;
ns->shm_ctlmni = SHMMNI;
ns->shm_rmid_forced = 0;
ns->shm_tot = 0;
ipc_init_ids(&shm_ids(ns));
}
/*
* Called with shm_ids.rwsem (writer) and the shp structure locked.
* Only shm_ids.rwsem remains locked on exit.
*/
static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
{
struct shmid_kernel *shp;
shp = container_of(ipcp, struct shmid_kernel, shm_perm);
WARN_ON(ns != shp->ns);
if (shp->shm_nattch) {
shp->shm_perm.mode |= SHM_DEST;
/* Do not find it any more */
ipc_set_key_private(&shm_ids(ns), &shp->shm_perm);
shm_unlock(shp);
} else
shm_destroy(ns, shp);
}
#ifdef CONFIG_IPC_NS
void shm_exit_ns(struct ipc_namespace *ns)
{
free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr);
rhashtable_destroy(&ns->ids[IPC_SHM_IDS].key_ht);
}
#endif
static int __init ipc_ns_init(void)
{
shm_init_ns(&init_ipc_ns);
return 0;
}
pure_initcall(ipc_ns_init);
void __init shm_init(void)
{
ipc_init_proc_interface("sysvipc/shm",
#if BITS_PER_LONG <= 32
" key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
#else
" key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
#endif
IPC_SHM_IDS, sysvipc_shm_proc_show);
}
static inline struct shmid_kernel *shm_obtain_object(struct ipc_namespace *ns, int id)
{
struct kern_ipc_perm *ipcp = ipc_obtain_object_idr(&shm_ids(ns), id);
if (IS_ERR(ipcp))
return ERR_CAST(ipcp);
return container_of(ipcp, struct shmid_kernel, shm_perm);
}
static inline struct shmid_kernel *shm_obtain_object_check(struct ipc_namespace *ns, int id)
{
struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&shm_ids(ns), id);
if (IS_ERR(ipcp))
return ERR_CAST(ipcp);
return container_of(ipcp, struct shmid_kernel, shm_perm);
}
/*
* shm_lock_(check_) routines are called in the paths where the rwsem
* is not necessarily held.
*/
static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
{
struct kern_ipc_perm *ipcp;
rcu_read_lock();
ipcp = ipc_obtain_object_idr(&shm_ids(ns), id);
if (IS_ERR(ipcp))
goto err;
ipc_lock_object(ipcp);
/*
* ipc_rmid() may have already freed the ID while ipc_lock_object()
* was spinning: here verify that the structure is still valid.
* Upon races with RMID, return -EIDRM, thus indicating that
* the ID points to a removed identifier.
*/
if (ipc_valid_object(ipcp)) {
/* return a locked ipc object upon success */
return container_of(ipcp, struct shmid_kernel, shm_perm);
}
ipc_unlock_object(ipcp);
ipcp = ERR_PTR(-EIDRM);
err:
rcu_read_unlock();
/*
* Callers of shm_lock() must validate the status of the returned ipc
* object pointer and error out as appropriate.
*/
return ERR_CAST(ipcp);
}
static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
{
rcu_read_lock();
ipc_lock_object(&ipcp->shm_perm);
}
static void shm_rcu_free(struct rcu_head *head)
{
struct kern_ipc_perm *ptr = container_of(head, struct kern_ipc_perm,
rcu);
struct shmid_kernel *shp = container_of(ptr, struct shmid_kernel,
shm_perm);
security_shm_free(&shp->shm_perm);
kfree(shp);
}
/*
* It has to be called with shp locked.
* It must be called before ipc_rmid()
*/
static inline void shm_clist_rm(struct shmid_kernel *shp)
{
struct task_struct *creator;
/* ensure that shm_creator does not disappear */
rcu_read_lock();
/*
* A concurrent exit_shm may do a list_del_init() as well.
* Just do nothing if exit_shm already did the work
*/
if (!list_empty(&shp->shm_clist)) {
/*
* shp->shm_creator is guaranteed to be valid *only*
* if shp->shm_clist is not empty.
*/
creator = shp->shm_creator;
task_lock(creator);
/*
* list_del_init() is a nop if the entry was already removed
* from the list.
*/
list_del_init(&shp->shm_clist);
task_unlock(creator);
}
rcu_read_unlock();
}
static inline void shm_rmid(struct shmid_kernel *s)
{
shm_clist_rm(s);
ipc_rmid(&shm_ids(s->ns), &s->shm_perm);
}
static int __shm_open(struct shm_file_data *sfd)
{
struct shmid_kernel *shp;
shp = shm_lock(sfd->ns, sfd->id);
if (IS_ERR(shp))
return PTR_ERR(shp);
if (shp->shm_file != sfd->file) {
/* ID was reused */
shm_unlock(shp);
return -EINVAL;
}
shp->shm_atim = ktime_get_real_seconds();
ipc_update_pid(&shp->shm_lprid, task_tgid(current));
shp->shm_nattch++;
shm_unlock(shp);
return 0;
}
/* This is called by fork, once for every shm attach. */
static void shm_open(struct vm_area_struct *vma)
{
struct file *file = vma->vm_file;
struct shm_file_data *sfd = shm_file_data(file);
int err;
/* Always call underlying open if present */
if (sfd->vm_ops->open)
sfd->vm_ops->open(vma);
err = __shm_open(sfd);
/*
* We raced in the idr lookup or with shm_destroy().
* Either way, the ID is busted.
*/
WARN_ON_ONCE(err);
}
/*
* shm_destroy - free the struct shmid_kernel
*
* @ns: namespace
* @shp: struct to free
*
* It has to be called with shp and shm_ids.rwsem (writer) locked,
* but returns with shp unlocked and freed.
*/
static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
{
struct file *shm_file;
shm_file = shp->shm_file;
shp->shm_file = NULL;
ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
shm_rmid(shp);
shm_unlock(shp);
if (!is_file_hugepages(shm_file))
shmem_lock(shm_file, 0, shp->mlock_ucounts);
fput(shm_file);
ipc_update_pid(&shp->shm_cprid, NULL);
ipc_update_pid(&shp->shm_lprid, NULL);
ipc_rcu_putref(&shp->shm_perm, shm_rcu_free);
}
/*
* shm_may_destroy - identifies whether shm segment should be destroyed now
*
* Returns true if and only if there are no active users of the segment and
* one of the following is true:
*
* 1) shmctl(id, IPC_RMID, NULL) was called for this shp
*
* 2) sysctl kernel.shm_rmid_forced is set to 1.
*/
static bool shm_may_destroy(struct shmid_kernel *shp)
{
return (shp->shm_nattch == 0) &&
(shp->ns->shm_rmid_forced ||
(shp->shm_perm.mode & SHM_DEST));
}
/*
* remove the attach descriptor vma.
* free memory for segment if it is marked destroyed.
* The descriptor has already been removed from the current->mm->mmap list
* and will later be kfree()d.
*/
static void __shm_close(struct shm_file_data *sfd)
{
struct shmid_kernel *shp;
struct ipc_namespace *ns = sfd->ns;
down_write(&shm_ids(ns).rwsem);
/* remove from the list of attaches of the shm segment */
shp = shm_lock(ns, sfd->id);
/*
* We raced in the idr lookup or with shm_destroy().
* Either way, the ID is busted.
*/
if (WARN_ON_ONCE(IS_ERR(shp)))
goto done; /* no-op */
ipc_update_pid(&shp->shm_lprid, task_tgid(current));
shp->shm_dtim = ktime_get_real_seconds();
shp->shm_nattch--;
if (shm_may_destroy(shp))
shm_destroy(ns, shp);
else
shm_unlock(shp);
done:
up_write(&shm_ids(ns).rwsem);
}
static void shm_close(struct vm_area_struct *vma)
{
struct file *file = vma->vm_file;
struct shm_file_data *sfd = shm_file_data(file);
/* Always call underlying close if present */
if (sfd->vm_ops->close)
sfd->vm_ops->close(vma);
__shm_close(sfd);
}
/* Called with ns->shm_ids(ns).rwsem locked */
static int shm_try_destroy_orphaned(int id, void *p, void *data)
{
struct ipc_namespace *ns = data;
struct kern_ipc_perm *ipcp = p;
struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
/*
* We want to destroy segments without users and with already
* exit'ed originating process.
*
* As shp->* are changed under rwsem, it's safe to skip shp locking.
*/
if (!list_empty(&shp->shm_clist))
return 0;
if (shm_may_destroy(shp)) {
shm_lock_by_ptr(shp);
shm_destroy(ns, shp);
}
return 0;
}
void shm_destroy_orphaned(struct ipc_namespace *ns)
{
down_write(&shm_ids(ns).rwsem);
if (shm_ids(ns).in_use)
idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns);
up_write(&shm_ids(ns).rwsem);
}
/* Locking assumes this will only be called with task == current */
void exit_shm(struct task_struct *task)
{
for (;;) {
struct shmid_kernel *shp;
struct ipc_namespace *ns;
task_lock(task);
if (list_empty(&task->sysvshm.shm_clist)) {
task_unlock(task);
break;
}
shp = list_first_entry(&task->sysvshm.shm_clist, struct shmid_kernel,
shm_clist);
/*
* 1) Get pointer to the ipc namespace. It is worth to say
* that this pointer is guaranteed to be valid because
* shp lifetime is always shorter than namespace lifetime
* in which shp lives.
* We taken task_lock it means that shp won't be freed.
*/
ns = shp->ns;
/*
* 2) If kernel.shm_rmid_forced is not set then only keep track of
* which shmids are orphaned, so that a later set of the sysctl
* can clean them up.
*/
if (!ns->shm_rmid_forced)
goto unlink_continue;
/*
* 3) get a reference to the namespace.
* The refcount could be already 0. If it is 0, then
* the shm objects will be free by free_ipc_work().
*/
ns = get_ipc_ns_not_zero(ns);
if (!ns) {
unlink_continue:
list_del_init(&shp->shm_clist);
task_unlock(task);
continue;
}
/*
* 4) get a reference to shp.
* This cannot fail: shm_clist_rm() is called before
* ipc_rmid(), thus the refcount cannot be 0.
*/
WARN_ON(!ipc_rcu_getref(&shp->shm_perm));
/*
* 5) unlink the shm segment from the list of segments
* created by current.
* This must be done last. After unlinking,
* only the refcounts obtained above prevent IPC_RMID
* from destroying the segment or the namespace.
*/
list_del_init(&shp->shm_clist);
task_unlock(task);
/*
* 6) we have all references
* Thus lock & if needed destroy shp.
*/
down_write(&shm_ids(ns).rwsem);
shm_lock_by_ptr(shp);
/*
* rcu_read_lock was implicitly taken in shm_lock_by_ptr, it's
* safe to call ipc_rcu_putref here
*/
ipc_rcu_putref(&shp->shm_perm, shm_rcu_free);
if (ipc_valid_object(&shp->shm_perm)) {
if (shm_may_destroy(shp))
shm_destroy(ns, shp);
else
shm_unlock(shp);
} else {
/*
* Someone else deleted the shp from namespace
* idr/kht while we have waited.
* Just unlock and continue.
*/
shm_unlock(shp);
}
up_write(&shm_ids(ns).rwsem);
put_ipc_ns(ns); /* paired with get_ipc_ns_not_zero */
}
}
static vm_fault_t shm_fault(struct vm_fault *vmf)
{
struct file *file = vmf->vma->vm_file;
struct shm_file_data *sfd = shm_file_data(file);
return sfd->vm_ops->fault(vmf);
}
static int shm_may_split(struct vm_area_struct *vma, unsigned long addr)
{
struct file *file = vma->vm_file;
struct shm_file_data *sfd = shm_file_data(file);
if (sfd->vm_ops->may_split)
return sfd->vm_ops->may_split(vma, addr);
return 0;
}
static unsigned long shm_pagesize(struct vm_area_struct *vma)
{
struct file *file = vma->vm_file;
struct shm_file_data *sfd = shm_file_data(file);
if (sfd->vm_ops->pagesize)
return sfd->vm_ops->pagesize(vma);
return PAGE_SIZE;
}
#ifdef CONFIG_NUMA
static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
{
struct file *file = vma->vm_file;
struct shm_file_data *sfd = shm_file_data(file);
int err = 0;
if (sfd->vm_ops->set_policy)
err = sfd->vm_ops->set_policy(vma, new);
return err;
}
static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
unsigned long addr)
{
struct file *file = vma->vm_file;
struct shm_file_data *sfd = shm_file_data(file);
struct mempolicy *pol = NULL;
if (sfd->vm_ops->get_policy)
pol = sfd->vm_ops->get_policy(vma, addr);
else if (vma->vm_policy)
pol = vma->vm_policy;
return pol;
}
#endif
static int shm_mmap(struct file *file, struct vm_area_struct *vma)
{
struct shm_file_data *sfd = shm_file_data(file);
int ret;
/*
* In case of remap_file_pages() emulation, the file can represent an
* IPC ID that was removed, and possibly even reused by another shm
* segment already. Propagate this case as an error to caller.
*/
ret = __shm_open(sfd);
if (ret)
return ret;
ret = call_mmap(sfd->file, vma);
if (ret) {
__shm_close(sfd);
return ret;
}
sfd->vm_ops = vma->vm_ops;
#ifdef CONFIG_MMU
WARN_ON(!sfd->vm_ops->fault);
#endif
vma->vm_ops = &shm_vm_ops;
return 0;
}
static int shm_release(struct inode *ino, struct file *file)
{
struct shm_file_data *sfd = shm_file_data(file);
put_ipc_ns(sfd->ns);
fput(sfd->file);
shm_file_data(file) = NULL;
kfree(sfd);
return 0;
}
static int shm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
{
struct shm_file_data *sfd = shm_file_data(file);
if (!sfd->file->f_op->fsync)
return -EINVAL;
return sfd->file->f_op->fsync(sfd->file, start, end, datasync);
}
static long shm_fallocate(struct file *file, int mode, loff_t offset,
loff_t len)
{
struct shm_file_data *sfd = shm_file_data(file);
if (!sfd->file->f_op->fallocate)
return -EOPNOTSUPP;
return sfd->file->f_op->fallocate(file, mode, offset, len);
}
static unsigned long shm_get_unmapped_area(struct file *file,
unsigned long addr, unsigned long len, unsigned long pgoff,
unsigned long flags)
{
struct shm_file_data *sfd = shm_file_data(file);
return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
pgoff, flags);
}
static const struct file_operations shm_file_operations = {
.mmap = shm_mmap,
.fsync = shm_fsync,
.release = shm_release,
.get_unmapped_area = shm_get_unmapped_area,
.llseek = noop_llseek,
.fallocate = shm_fallocate,
};
/*
* shm_file_operations_huge is now identical to shm_file_operations,
* but we keep it distinct for the sake of is_file_shm_hugepages().
*/
static const struct file_operations shm_file_operations_huge = {
.mmap = shm_mmap,
.fsync = shm_fsync,
.release = shm_release,
.get_unmapped_area = shm_get_unmapped_area,
.llseek = noop_llseek,
.fallocate = shm_fallocate,
};
bool is_file_shm_hugepages(struct file *file)
{
return file->f_op == &shm_file_operations_huge;
}
static const struct vm_operations_struct shm_vm_ops = {
.open = shm_open, /* callback for a new vm-area open */
.close = shm_close, /* callback for when the vm-area is released */
.fault = shm_fault,
.may_split = shm_may_split,
.pagesize = shm_pagesize,
#if defined(CONFIG_NUMA)
.set_policy = shm_set_policy,
.get_policy = shm_get_policy,
#endif
};
/**
* newseg - Create a new shared memory segment
* @ns: namespace
* @params: ptr to the structure that contains key, size and shmflg
*
* Called with shm_ids.rwsem held as a writer.
*/
static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
{
key_t key = params->key;
int shmflg = params->flg;
size_t size = params->u.size;
int error;
struct shmid_kernel *shp;
size_t numpages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
struct file *file;
char name[13];
vm_flags_t acctflag = 0;
if (size < SHMMIN || size > ns->shm_ctlmax)
return -EINVAL;
if (numpages << PAGE_SHIFT < size)
return -ENOSPC;
if (ns->shm_tot + numpages < ns->shm_tot ||
ns->shm_tot + numpages > ns->shm_ctlall)
return -ENOSPC;
shp = kmalloc(sizeof(*shp), GFP_KERNEL_ACCOUNT);
if (unlikely(!shp))
return -ENOMEM;
shp->shm_perm.key = key;
shp->shm_perm.mode = (shmflg & S_IRWXUGO);
shp->mlock_ucounts = NULL;
shp->shm_perm.security = NULL;
error = security_shm_alloc(&shp->shm_perm);
if (error) {
kfree(shp);
return error;
}
sprintf(name, "SYSV%08x", key);
if (shmflg & SHM_HUGETLB) {
struct hstate *hs;
size_t hugesize;
hs = hstate_sizelog((shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
if (!hs) {
error = -EINVAL;
goto no_file;
}
hugesize = ALIGN(size, huge_page_size(hs));
/* hugetlb_file_setup applies strict accounting */
if (shmflg & SHM_NORESERVE)
acctflag = VM_NORESERVE;
file = hugetlb_file_setup(name, hugesize, acctflag,
HUGETLB_SHMFS_INODE, (shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
} else {
/*
* Do not allow no accounting for OVERCOMMIT_NEVER, even
* if it's asked for.
*/
if ((shmflg & SHM_NORESERVE) &&
sysctl_overcommit_memory != OVERCOMMIT_NEVER)
acctflag = VM_NORESERVE;
file = shmem_kernel_file_setup(name, size, acctflag);
}
error = PTR_ERR(file);
if (IS_ERR(file))
goto no_file;
shp->shm_cprid = get_pid(task_tgid(current));
shp->shm_lprid = NULL;
shp->shm_atim = shp->shm_dtim = 0;
shp->shm_ctim = ktime_get_real_seconds();
shp->shm_segsz = size;
shp->shm_nattch = 0;
shp->shm_file = file;
shp->shm_creator = current;
/* ipc_addid() locks shp upon success. */
error = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
if (error < 0)
goto no_id;
shp->ns = ns;
task_lock(current);
list_add(&shp->shm_clist, ¤t->sysvshm.shm_clist);
task_unlock(current);
/*
* shmid gets reported as "inode#" in /proc/pid/maps.
* proc-ps tools use this. Changing this will break them.
*/
file_inode(file)->i_ino = shp->shm_perm.id;
ns->shm_tot += numpages;
error = shp->shm_perm.id;
ipc_unlock_object(&shp->shm_perm);
rcu_read_unlock();
return error;
no_id:
ipc_update_pid(&shp->shm_cprid, NULL);
ipc_update_pid(&shp->shm_lprid, NULL);
fput(file);
ipc_rcu_putref(&shp->shm_perm, shm_rcu_free);
return error;
no_file:
call_rcu(&shp->shm_perm.rcu, shm_rcu_free);
return error;
}
/*
* Called with shm_ids.rwsem and ipcp locked.
*/
static int shm_more_checks(struct kern_ipc_perm *ipcp, struct ipc_params *params)
{
struct shmid_kernel *shp;
shp = container_of(ipcp, struct shmid_kernel, shm_perm);
if (shp->shm_segsz < params->u.size)
return -EINVAL;
return 0;
}
long ksys_shmget(key_t key, size_t size, int shmflg)
{
struct ipc_namespace *ns;
static const struct ipc_ops shm_ops = {
.getnew = newseg,
.associate = security_shm_associate,
.more_checks = shm_more_checks,
};
struct ipc_params shm_params;
ns = current->nsproxy->ipc_ns;
shm_params.key = key;
shm_params.flg = shmflg;
shm_params.u.size = size;
return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
}
SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
{
return ksys_shmget(key, size, shmflg);
}
static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
{
switch (version) {
case IPC_64:
return copy_to_user(buf, in, sizeof(*in));
case IPC_OLD:
{
struct shmid_ds out;
memset(&out, 0, sizeof(out));
ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
out.shm_segsz = in->shm_segsz;
out.shm_atime = in->shm_atime;
out.shm_dtime = in->shm_dtime;
out.shm_ctime = in->shm_ctime;
out.shm_cpid = in->shm_cpid;
out.shm_lpid = in->shm_lpid;
out.shm_nattch = in->shm_nattch;
return copy_to_user(buf, &out, sizeof(out));
}
default:
return -EINVAL;
}
}
static inline unsigned long
copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
{
switch (version) {
case IPC_64:
if (copy_from_user(out, buf, sizeof(*out)))
return -EFAULT;
return 0;
case IPC_OLD:
{
struct shmid_ds tbuf_old;
if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
return -EFAULT;
out->shm_perm.uid = tbuf_old.shm_perm.uid;
out->shm_perm.gid = tbuf_old.shm_perm.gid;
out->shm_perm.mode = tbuf_old.shm_perm.mode;
return 0;
}
default:
return -EINVAL;
}
}
static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
{
switch (version) {
case IPC_64:
return copy_to_user(buf, in, sizeof(*in));
case IPC_OLD:
{
struct shminfo out;
if (in->shmmax > INT_MAX)
out.shmmax = INT_MAX;
else
out.shmmax = (int)in->shmmax;
out.shmmin = in->shmmin;
out.shmmni = in->shmmni;
out.shmseg = in->shmseg;
out.shmall = in->shmall;
return copy_to_user(buf, &out, sizeof(out));
}
default:
return -EINVAL;
}
}
/*
* Calculate and add used RSS and swap pages of a shm.
* Called with shm_ids.rwsem held as a reader
*/
static void shm_add_rss_swap(struct shmid_kernel *shp,
unsigned long *rss_add, unsigned long *swp_add)
{
struct inode *inode;
inode = file_inode(shp->shm_file);
if (is_file_hugepages(shp->shm_file)) {
struct address_space *mapping = inode->i_mapping;
struct hstate *h = hstate_file(shp->shm_file);
*rss_add += pages_per_huge_page(h) * mapping->nrpages;
} else {
#ifdef CONFIG_SHMEM
struct shmem_inode_info *info = SHMEM_I(inode);
spin_lock_irq(&info->lock);
*rss_add += inode->i_mapping->nrpages;
*swp_add += info->swapped;
spin_unlock_irq(&info->lock);
#else
*rss_add += inode->i_mapping->nrpages;
#endif
}
}
/*
* Called with shm_ids.rwsem held as a reader
*/
static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
unsigned long *swp)
{
int next_id;
int total, in_use;
*rss = 0;
*swp = 0;
in_use = shm_ids(ns).in_use;
for (total = 0, next_id = 0; total < in_use; next_id++) {
struct kern_ipc_perm *ipc;
struct shmid_kernel *shp;
ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
if (ipc == NULL)
continue;
shp = container_of(ipc, struct shmid_kernel, shm_perm);
shm_add_rss_swap(shp, rss, swp);
total++;
}
}
/*
* This function handles some shmctl commands which require the rwsem
* to be held in write mode.
* NOTE: no locks must be held, the rwsem is taken inside this function.
*/
static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
struct shmid64_ds *shmid64)
{
struct kern_ipc_perm *ipcp;
struct shmid_kernel *shp;
int err;
down_write(&shm_ids(ns).rwsem);
rcu_read_lock();
ipcp = ipcctl_obtain_check(ns, &shm_ids(ns), shmid, cmd,
&shmid64->shm_perm, 0);
if (IS_ERR(ipcp)) {
err = PTR_ERR(ipcp);
goto out_unlock1;
}
shp = container_of(ipcp, struct shmid_kernel, shm_perm);
err = security_shm_shmctl(&shp->shm_perm, cmd);
if (err)
goto out_unlock1;
switch (cmd) {
case IPC_RMID:
ipc_lock_object(&shp->shm_perm);
/* do_shm_rmid unlocks the ipc object and rcu */
do_shm_rmid(ns, ipcp);
goto out_up;
case IPC_SET:
ipc_lock_object(&shp->shm_perm);
err = ipc_update_perm(&shmid64->shm_perm, ipcp);
if (err)
goto out_unlock0;
shp->shm_ctim = ktime_get_real_seconds();
break;
default:
err = -EINVAL;
goto out_unlock1;
}
out_unlock0:
ipc_unlock_object(&shp->shm_perm);
out_unlock1:
rcu_read_unlock();
out_up:
up_write(&shm_ids(ns).rwsem);
return err;
}
static int shmctl_ipc_info(struct ipc_namespace *ns,
struct shminfo64 *shminfo)
{
int err = security_shm_shmctl(NULL, IPC_INFO);
if (!err) {
memset(shminfo, 0, sizeof(*shminfo));
shminfo->shmmni = shminfo->shmseg = ns->shm_ctlmni;
shminfo->shmmax = ns->shm_ctlmax;
shminfo->shmall = ns->shm_ctlall;
shminfo->shmmin = SHMMIN;
down_read(&shm_ids(ns).rwsem);
err = ipc_get_maxidx(&shm_ids(ns));
up_read(&shm_ids(ns).rwsem);
if (err < 0)
err = 0;
}
return err;
}
static int shmctl_shm_info(struct ipc_namespace *ns,
struct shm_info *shm_info)
{
int err = security_shm_shmctl(NULL, SHM_INFO);
if (!err) {
memset(shm_info, 0, sizeof(*shm_info));
down_read(&shm_ids(ns).rwsem);
shm_info->used_ids = shm_ids(ns).in_use;
shm_get_stat(ns, &shm_info->shm_rss, &shm_info->shm_swp);
shm_info->shm_tot = ns->shm_tot;
shm_info->swap_attempts = 0;
shm_info->swap_successes = 0;
err = ipc_get_maxidx(&shm_ids(ns));
up_read(&shm_ids(ns).rwsem);
if (err < 0)
err = 0;
}
return err;
}
static int shmctl_stat(struct ipc_namespace *ns, int shmid,
int cmd, struct shmid64_ds *tbuf)
{
struct shmid_kernel *shp;
int err;
memset(tbuf, 0, sizeof(*tbuf));
rcu_read_lock();
if (cmd == SHM_STAT || cmd == SHM_STAT_ANY) {
shp = shm_obtain_object(ns, shmid);
if (IS_ERR(shp)) {
err = PTR_ERR(shp);
goto out_unlock;
}
} else { /* IPC_STAT */
shp = shm_obtain_object_check(ns, shmid);
if (IS_ERR(shp)) {
err = PTR_ERR(shp);
goto out_unlock;
}
}
/*
* Semantically SHM_STAT_ANY ought to be identical to
* that functionality provided by the /proc/sysvipc/
* interface. As such, only audit these calls and
* do not do traditional S_IRUGO permission checks on
* the ipc object.
*/
if (cmd == SHM_STAT_ANY)
audit_ipc_obj(&shp->shm_perm);
else {
err = -EACCES;
if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
goto out_unlock;
}
err = security_shm_shmctl(&shp->shm_perm, cmd);
if (err)
goto out_unlock;
ipc_lock_object(&shp->shm_perm);
if (!ipc_valid_object(&shp->shm_perm)) {
ipc_unlock_object(&shp->shm_perm);
err = -EIDRM;
goto out_unlock;
}
kernel_to_ipc64_perm(&shp->shm_perm, &tbuf->shm_perm);
tbuf->shm_segsz = shp->shm_segsz;
tbuf->shm_atime = shp->shm_atim;
tbuf->shm_dtime = shp->shm_dtim;
tbuf->shm_ctime = shp->shm_ctim;
#ifndef CONFIG_64BIT
tbuf->shm_atime_high = shp->shm_atim >> 32;
tbuf->shm_dtime_high = shp->shm_dtim >> 32;
tbuf->shm_ctime_high = shp->shm_ctim >> 32;
#endif
tbuf->shm_cpid = pid_vnr(shp->shm_cprid);
tbuf->shm_lpid = pid_vnr(shp->shm_lprid);
tbuf->shm_nattch = shp->shm_nattch;
if (cmd == IPC_STAT) {
/*
* As defined in SUS:
* Return 0 on success
*/
err = 0;
} else {
/*
* SHM_STAT and SHM_STAT_ANY (both Linux specific)
* Return the full id, including the sequence number
*/
err = shp->shm_perm.id;
}
ipc_unlock_object(&shp->shm_perm);
out_unlock:
rcu_read_unlock();
return err;
}
static int shmctl_do_lock(struct ipc_namespace *ns, int shmid, int cmd)
{
struct shmid_kernel *shp;
struct file *shm_file;
int err;
rcu_read_lock();
shp = shm_obtain_object_check(ns, shmid);
if (IS_ERR(shp)) {
err = PTR_ERR(shp);
goto out_unlock1;
}
audit_ipc_obj(&(shp->shm_perm));
err = security_shm_shmctl(&shp->shm_perm, cmd);
if (err)
goto out_unlock1;
ipc_lock_object(&shp->shm_perm);
/* check if shm_destroy() is tearing down shp */
if (!ipc_valid_object(&shp->shm_perm)) {
err = -EIDRM;
goto out_unlock0;
}
if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
kuid_t euid = current_euid();
if (!uid_eq(euid, shp->shm_perm.uid) &&
!uid_eq(euid, shp->shm_perm.cuid)) {
err = -EPERM;
goto out_unlock0;
}
if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK)) {
err = -EPERM;
goto out_unlock0;
}
}
shm_file = shp->shm_file;
if (is_file_hugepages(shm_file))
goto out_unlock0;
if (cmd == SHM_LOCK) {
struct ucounts *ucounts = current_ucounts();
err = shmem_lock(shm_file, 1, ucounts);
if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) {
shp->shm_perm.mode |= SHM_LOCKED;
shp->mlock_ucounts = ucounts;
}
goto out_unlock0;
}
/* SHM_UNLOCK */
if (!(shp->shm_perm.mode & SHM_LOCKED))
goto out_unlock0;
shmem_lock(shm_file, 0, shp->mlock_ucounts);
shp->shm_perm.mode &= ~SHM_LOCKED;
shp->mlock_ucounts = NULL;
get_file(shm_file);
ipc_unlock_object(&shp->shm_perm);
rcu_read_unlock();
shmem_unlock_mapping(shm_file->f_mapping);
fput(shm_file);
return err;
out_unlock0:
ipc_unlock_object(&shp->shm_perm);
out_unlock1:
rcu_read_unlock();
return err;
}
static long ksys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf, int version)
{
int err;
struct ipc_namespace *ns;
struct shmid64_ds sem64;
if (cmd < 0 || shmid < 0)
return -EINVAL;
ns = current->nsproxy->ipc_ns;
switch (cmd) {
case IPC_INFO: {
struct shminfo64 shminfo;
err = shmctl_ipc_info(ns, &shminfo);
if (err < 0)
return err;
if (copy_shminfo_to_user(buf, &shminfo, version))
err = -EFAULT;
return err;
}
case SHM_INFO: {
struct shm_info shm_info;
err = shmctl_shm_info(ns, &shm_info);
if (err < 0)
return err;
if (copy_to_user(buf, &shm_info, sizeof(shm_info)))
err = -EFAULT;
return err;
}
case SHM_STAT:
case SHM_STAT_ANY:
case IPC_STAT: {
err = shmctl_stat(ns, shmid, cmd, &sem64);
if (err < 0)
return err;
if (copy_shmid_to_user(buf, &sem64, version))
err = -EFAULT;
return err;
}
case IPC_SET:
if (copy_shmid_from_user(&sem64, buf, version))
return -EFAULT;
fallthrough;
case IPC_RMID:
return shmctl_down(ns, shmid, cmd, &sem64);
case SHM_LOCK:
case SHM_UNLOCK:
return shmctl_do_lock(ns, shmid, cmd);
default:
return -EINVAL;
}
}
SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
{
return ksys_shmctl(shmid, cmd, buf, IPC_64);
}
#ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
long ksys_old_shmctl(int shmid, int cmd, struct shmid_ds __user *buf)
{
int version = ipc_parse_version(&cmd);
return ksys_shmctl(shmid, cmd, buf, version);
}
SYSCALL_DEFINE3(old_shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
{
return ksys_old_shmctl(shmid, cmd, buf);
}
#endif
#ifdef CONFIG_COMPAT
struct compat_shmid_ds {
struct compat_ipc_perm shm_perm;
int shm_segsz;
old_time32_t shm_atime;
old_time32_t shm_dtime;
old_time32_t shm_ctime;
compat_ipc_pid_t shm_cpid;
compat_ipc_pid_t shm_lpid;
unsigned short shm_nattch;
unsigned short shm_unused;
compat_uptr_t shm_unused2;
compat_uptr_t shm_unused3;
};
struct compat_shminfo64 {
compat_ulong_t shmmax;
compat_ulong_t shmmin;
compat_ulong_t shmmni;
compat_ulong_t shmseg;
compat_ulong_t shmall;
compat_ulong_t __unused1;
compat_ulong_t __unused2;
compat_ulong_t __unused3;
compat_ulong_t __unused4;
};
struct compat_shm_info {
compat_int_t used_ids;
compat_ulong_t shm_tot, shm_rss, shm_swp;
compat_ulong_t swap_attempts, swap_successes;
};
static int copy_compat_shminfo_to_user(void __user *buf, struct shminfo64 *in,
int version)
{
if (in->shmmax > INT_MAX)
in->shmmax = INT_MAX;
if (version == IPC_64) {
struct compat_shminfo64 info;
memset(&info, 0, sizeof(info));
info.shmmax = in->shmmax;
info.shmmin = in->shmmin;
info.shmmni = in->shmmni;
info.shmseg = in->shmseg;
info.shmall = in->shmall;
return copy_to_user(buf, &info, sizeof(info));
} else {
struct shminfo info;
memset(&info, 0, sizeof(info));
info.shmmax = in->shmmax;
info.shmmin = in->shmmin;
info.shmmni = in->shmmni;
info.shmseg = in->shmseg;
info.shmall = in->shmall;
return copy_to_user(buf, &info, sizeof(info));
}
}
static int put_compat_shm_info(struct shm_info *ip,
struct compat_shm_info __user *uip)
{
struct compat_shm_info info;
memset(&info, 0, sizeof(info));
info.used_ids = ip->used_ids;
info.shm_tot = ip->shm_tot;
info.shm_rss = ip->shm_rss;
info.shm_swp = ip->shm_swp;
info.swap_attempts = ip->swap_attempts;
info.swap_successes = ip->swap_successes;
return copy_to_user(uip, &info, sizeof(info));
}
static int copy_compat_shmid_to_user(void __user *buf, struct shmid64_ds *in,
int version)
{
if (version == IPC_64) {
struct compat_shmid64_ds v;
memset(&v, 0, sizeof(v));
to_compat_ipc64_perm(&v.shm_perm, &in->shm_perm);
v.shm_atime = lower_32_bits(in->shm_atime);
v.shm_atime_high = upper_32_bits(in->shm_atime);
v.shm_dtime = lower_32_bits(in->shm_dtime);
v.shm_dtime_high = upper_32_bits(in->shm_dtime);
v.shm_ctime = lower_32_bits(in->shm_ctime);
v.shm_ctime_high = upper_32_bits(in->shm_ctime);
v.shm_segsz = in->shm_segsz;
v.shm_nattch = in->shm_nattch;
v.shm_cpid = in->shm_cpid;
v.shm_lpid = in->shm_lpid;
return copy_to_user(buf, &v, sizeof(v));
} else {
struct compat_shmid_ds v;
memset(&v, 0, sizeof(v));
to_compat_ipc_perm(&v.shm_perm, &in->shm_perm);
v.shm_perm.key = in->shm_perm.key;
v.shm_atime = in->shm_atime;
v.shm_dtime = in->shm_dtime;
v.shm_ctime = in->shm_ctime;
v.shm_segsz = in->shm_segsz;
v.shm_nattch = in->shm_nattch;
v.shm_cpid = in->shm_cpid;
v.shm_lpid = in->shm_lpid;
return copy_to_user(buf, &v, sizeof(v));
}
}
static int copy_compat_shmid_from_user(struct shmid64_ds *out, void __user *buf,
int version)
{
memset(out, 0, sizeof(*out));
if (version == IPC_64) {
struct compat_shmid64_ds __user *p = buf;
return get_compat_ipc64_perm(&out->shm_perm, &p->shm_perm);
} else {
struct compat_shmid_ds __user *p = buf;
return get_compat_ipc_perm(&out->shm_perm, &p->shm_perm);
}
}
static long compat_ksys_shmctl(int shmid, int cmd, void __user *uptr, int version)
{
struct ipc_namespace *ns;
struct shmid64_ds sem64;
int err;
ns = current->nsproxy->ipc_ns;
if (cmd < 0 || shmid < 0)
return -EINVAL;
switch (cmd) {
case IPC_INFO: {
struct shminfo64 shminfo;
err = shmctl_ipc_info(ns, &shminfo);
if (err < 0)
return err;
if (copy_compat_shminfo_to_user(uptr, &shminfo, version))
err = -EFAULT;
return err;
}
case SHM_INFO: {
struct shm_info shm_info;
err = shmctl_shm_info(ns, &shm_info);
if (err < 0)
return err;
if (put_compat_shm_info(&shm_info, uptr))
err = -EFAULT;
return err;
}
case IPC_STAT:
case SHM_STAT_ANY:
case SHM_STAT:
err = shmctl_stat(ns, shmid, cmd, &sem64);
if (err < 0)
return err;
if (copy_compat_shmid_to_user(uptr, &sem64, version))
err = -EFAULT;
return err;
case IPC_SET:
if (copy_compat_shmid_from_user(&sem64, uptr, version))
return -EFAULT;
fallthrough;
case IPC_RMID:
return shmctl_down(ns, shmid, cmd, &sem64);
case SHM_LOCK:
case SHM_UNLOCK:
return shmctl_do_lock(ns, shmid, cmd);
default:
return -EINVAL;
}
return err;
}
COMPAT_SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, void __user *, uptr)
{
return compat_ksys_shmctl(shmid, cmd, uptr, IPC_64);
}
#ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION
long compat_ksys_old_shmctl(int shmid, int cmd, void __user *uptr)
{
int version = compat_ipc_parse_version(&cmd);
return compat_ksys_shmctl(shmid, cmd, uptr, version);
}
COMPAT_SYSCALL_DEFINE3(old_shmctl, int, shmid, int, cmd, void __user *, uptr)
{
return compat_ksys_old_shmctl(shmid, cmd, uptr);
}
#endif
#endif
/*
* Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
*
* NOTE! Despite the name, this is NOT a direct system call entrypoint. The
* "raddr" thing points to kernel space, and there has to be a wrapper around
* this.
*/
long do_shmat(int shmid, char __user *shmaddr, int shmflg,
ulong *raddr, unsigned long shmlba)
{
struct shmid_kernel *shp;
unsigned long addr = (unsigned long)shmaddr;
unsigned long size;
struct file *file, *base;
int err;
unsigned long flags = MAP_SHARED;
unsigned long prot;
int acc_mode;
struct ipc_namespace *ns;
struct shm_file_data *sfd;
int f_flags;
unsigned long populate = 0;
err = -EINVAL;
if (shmid < 0)
goto out;
if (addr) {
if (addr & (shmlba - 1)) {
if (shmflg & SHM_RND) {
addr &= ~(shmlba - 1); /* round down */
/*
* Ensure that the round-down is non-nil
* when remapping. This can happen for
* cases when addr < shmlba.
*/
if (!addr && (shmflg & SHM_REMAP))
goto out;
} else
#ifndef __ARCH_FORCE_SHMLBA
if (addr & ~PAGE_MASK)
#endif
goto out;
}
flags |= MAP_FIXED;
} else if ((shmflg & SHM_REMAP))
goto out;
if (shmflg & SHM_RDONLY) {
prot = PROT_READ;
acc_mode = S_IRUGO;
f_flags = O_RDONLY;
} else {
prot = PROT_READ | PROT_WRITE;
acc_mode = S_IRUGO | S_IWUGO;
f_flags = O_RDWR;
}
if (shmflg & SHM_EXEC) {
prot |= PROT_EXEC;
acc_mode |= S_IXUGO;
}
/*
* We cannot rely on the fs check since SYSV IPC does have an
* additional creator id...
*/
ns = current->nsproxy->ipc_ns;
rcu_read_lock();
shp = shm_obtain_object_check(ns, shmid);
if (IS_ERR(shp)) {
err = PTR_ERR(shp);
goto out_unlock;
}
err = -EACCES;
if (ipcperms(ns, &shp->shm_perm, acc_mode))
goto out_unlock;
err = security_shm_shmat(&shp->shm_perm, shmaddr, shmflg);
if (err)
goto out_unlock;
ipc_lock_object(&shp->shm_perm);
/* check if shm_destroy() is tearing down shp */
if (!ipc_valid_object(&shp->shm_perm)) {
ipc_unlock_object(&shp->shm_perm);
err = -EIDRM;
goto out_unlock;
}
/*
* We need to take a reference to the real shm file to prevent the
* pointer from becoming stale in cases where the lifetime of the outer
* file extends beyond that of the shm segment. It's not usually
* possible, but it can happen during remap_file_pages() emulation as
* that unmaps the memory, then does ->mmap() via file reference only.
* We'll deny the ->mmap() if the shm segment was since removed, but to
* detect shm ID reuse we need to compare the file pointers.
*/
base = get_file(shp->shm_file);
shp->shm_nattch++;
size = i_size_read(file_inode(base));
ipc_unlock_object(&shp->shm_perm);
rcu_read_unlock();
err = -ENOMEM;
sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
if (!sfd) {
fput(base);
goto out_nattch;
}
file = alloc_file_clone(base, f_flags,
is_file_hugepages(base) ?
&shm_file_operations_huge :
&shm_file_operations);
err = PTR_ERR(file);
if (IS_ERR(file)) {
kfree(sfd);
fput(base);
goto out_nattch;
}
sfd->id = shp->shm_perm.id;
sfd->ns = get_ipc_ns(ns);
sfd->file = base;
sfd->vm_ops = NULL;
file->private_data = sfd;
err = security_mmap_file(file, prot, flags);
if (err)
goto out_fput;
if (mmap_write_lock_killable(current->mm)) {
err = -EINTR;
goto out_fput;
}
if (addr && !(shmflg & SHM_REMAP)) {
err = -EINVAL;
if (addr + size < addr)
goto invalid;
if (find_vma_intersection(current->mm, addr, addr + size))
goto invalid;
}
addr = do_mmap(file, addr, size, prot, flags, 0, 0, &populate, NULL);
*raddr = addr;
err = 0;
if (IS_ERR_VALUE(addr))
err = (long)addr;
invalid:
mmap_write_unlock(current->mm);
if (populate)
mm_populate(addr, populate);
out_fput:
fput(file);
out_nattch:
down_write(&shm_ids(ns).rwsem);
shp = shm_lock(ns, shmid);
shp->shm_nattch--;
if (shm_may_destroy(shp))
shm_destroy(ns, shp);
else
shm_unlock(shp);
up_write(&shm_ids(ns).rwsem);
return err;
out_unlock:
rcu_read_unlock();
out:
return err;
}
SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
{
unsigned long ret;
long err;
err = do_shmat(shmid, shmaddr, shmflg, &ret, SHMLBA);
if (err)
return err;
force_successful_syscall_return();
return (long)ret;
}
#ifdef CONFIG_COMPAT
#ifndef COMPAT_SHMLBA
#define COMPAT_SHMLBA SHMLBA
#endif
COMPAT_SYSCALL_DEFINE3(shmat, int, shmid, compat_uptr_t, shmaddr, int, shmflg)
{
unsigned long ret;
long err;
err = do_shmat(shmid, compat_ptr(shmaddr), shmflg, &ret, COMPAT_SHMLBA);
if (err)
return err;
force_successful_syscall_return();
return (long)ret;
}
#endif
/*
* detach and kill segment if marked destroyed.
* The work is done in shm_close.
*/
long ksys_shmdt(char __user *shmaddr)
{
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
unsigned long addr = (unsigned long)shmaddr;
int retval = -EINVAL;
#ifdef CONFIG_MMU
loff_t size = 0;
struct file *file;
VMA_ITERATOR(vmi, mm, addr);
#endif
if (addr & ~PAGE_MASK)
return retval;
if (mmap_write_lock_killable(mm))
return -EINTR;
/*
* This function tries to be smart and unmap shm segments that
* were modified by partial mlock or munmap calls:
* - It first determines the size of the shm segment that should be
* unmapped: It searches for a vma that is backed by shm and that
* started at address shmaddr. It records it's size and then unmaps
* it.
* - Then it unmaps all shm vmas that started at shmaddr and that
* are within the initially determined size and that are from the
* same shm segment from which we determined the size.
* Errors from do_munmap are ignored: the function only fails if
* it's called with invalid parameters or if it's called to unmap
* a part of a vma. Both calls in this function are for full vmas,
* the parameters are directly copied from the vma itself and always
* valid - therefore do_munmap cannot fail. (famous last words?)
*/
/*
* If it had been mremap()'d, the starting address would not
* match the usual checks anyway. So assume all vma's are
* above the starting address given.
*/
#ifdef CONFIG_MMU
for_each_vma(vmi, vma) {
/*
* Check if the starting address would match, i.e. it's
* a fragment created by mprotect() and/or munmap(), or it
* otherwise it starts at this address with no hassles.
*/
if ((vma->vm_ops == &shm_vm_ops) &&
(vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
/*
* Record the file of the shm segment being
* unmapped. With mremap(), someone could place
* page from another segment but with equal offsets
* in the range we are unmapping.
*/
file = vma->vm_file;
size = i_size_read(file_inode(vma->vm_file));
do_vma_munmap(&vmi, vma, vma->vm_start, vma->vm_end,
NULL, false);
/*
* We discovered the size of the shm segment, so
* break out of here and fall through to the next
* loop that uses the size information to stop
* searching for matching vma's.
*/
retval = 0;
vma = vma_next(&vmi);
break;
}
}
/*
* We need look no further than the maximum address a fragment
* could possibly have landed at. Also cast things to loff_t to
* prevent overflows and make comparisons vs. equal-width types.
*/
size = PAGE_ALIGN(size);
while (vma && (loff_t)(vma->vm_end - addr) <= size) {
/* finding a matching vma now does not alter retval */
if ((vma->vm_ops == &shm_vm_ops) &&
((vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) &&
(vma->vm_file == file)) {
do_vma_munmap(&vmi, vma, vma->vm_start, vma->vm_end,
NULL, false);
}
vma = vma_next(&vmi);
}
#else /* CONFIG_MMU */
vma = vma_lookup(mm, addr);
/* under NOMMU conditions, the exact address to be destroyed must be
* given
*/
if (vma && vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start, NULL);
retval = 0;
}
#endif
mmap_write_unlock(mm);
return retval;
}
SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
{
return ksys_shmdt(shmaddr);
}
#ifdef CONFIG_PROC_FS
static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
{
struct pid_namespace *pid_ns = ipc_seq_pid_ns(s);
struct user_namespace *user_ns = seq_user_ns(s);
struct kern_ipc_perm *ipcp = it;
struct shmid_kernel *shp;
unsigned long rss = 0, swp = 0;
shp = container_of(ipcp, struct shmid_kernel, shm_perm);
shm_add_rss_swap(shp, &rss, &swp);
#if BITS_PER_LONG <= 32
#define SIZE_SPEC "%10lu"
#else
#define SIZE_SPEC "%21lu"
#endif
seq_printf(s,
"%10d %10d %4o " SIZE_SPEC " %5u %5u "
"%5lu %5u %5u %5u %5u %10llu %10llu %10llu "
SIZE_SPEC " " SIZE_SPEC "\n",
shp->shm_perm.key,
shp->shm_perm.id,
shp->shm_perm.mode,
shp->shm_segsz,
pid_nr_ns(shp->shm_cprid, pid_ns),
pid_nr_ns(shp->shm_lprid, pid_ns),
shp->shm_nattch,
from_kuid_munged(user_ns, shp->shm_perm.uid),
from_kgid_munged(user_ns, shp->shm_perm.gid),
from_kuid_munged(user_ns, shp->shm_perm.cuid),
from_kgid_munged(user_ns, shp->shm_perm.cgid),
shp->shm_atim,
shp->shm_dtim,
shp->shm_ctim,
rss * PAGE_SIZE,
swp * PAGE_SIZE);
return 0;
}
#endif
| linux-master | ipc/shm.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2007
*
* Author: Eric Biederman <[email protected]>
*/
#include <linux/module.h>
#include <linux/ipc.h>
#include <linux/nsproxy.h>
#include <linux/sysctl.h>
#include <linux/uaccess.h>
#include <linux/capability.h>
#include <linux/ipc_namespace.h>
#include <linux/msg.h>
#include <linux/slab.h>
#include "util.h"
static int proc_ipc_dointvec_minmax_orphans(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
struct ipc_namespace *ns =
container_of(table->data, struct ipc_namespace, shm_rmid_forced);
int err;
err = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
if (err < 0)
return err;
if (ns->shm_rmid_forced)
shm_destroy_orphaned(ns);
return err;
}
static int proc_ipc_auto_msgmni(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
struct ctl_table ipc_table;
int dummy = 0;
memcpy(&ipc_table, table, sizeof(ipc_table));
ipc_table.data = &dummy;
if (write)
pr_info_once("writing to auto_msgmni has no effect");
return proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos);
}
static int proc_ipc_sem_dointvec(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
struct ipc_namespace *ns =
container_of(table->data, struct ipc_namespace, sem_ctls);
int ret, semmni;
semmni = ns->sem_ctls[3];
ret = proc_dointvec(table, write, buffer, lenp, ppos);
if (!ret)
ret = sem_check_semmni(ns);
/*
* Reset the semmni value if an error happens.
*/
if (ret)
ns->sem_ctls[3] = semmni;
return ret;
}
int ipc_mni = IPCMNI;
int ipc_mni_shift = IPCMNI_SHIFT;
int ipc_min_cycle = RADIX_TREE_MAP_SIZE;
static struct ctl_table ipc_sysctls[] = {
{
.procname = "shmmax",
.data = &init_ipc_ns.shm_ctlmax,
.maxlen = sizeof(init_ipc_ns.shm_ctlmax),
.mode = 0644,
.proc_handler = proc_doulongvec_minmax,
},
{
.procname = "shmall",
.data = &init_ipc_ns.shm_ctlall,
.maxlen = sizeof(init_ipc_ns.shm_ctlall),
.mode = 0644,
.proc_handler = proc_doulongvec_minmax,
},
{
.procname = "shmmni",
.data = &init_ipc_ns.shm_ctlmni,
.maxlen = sizeof(init_ipc_ns.shm_ctlmni),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = &ipc_mni,
},
{
.procname = "shm_rmid_forced",
.data = &init_ipc_ns.shm_rmid_forced,
.maxlen = sizeof(init_ipc_ns.shm_rmid_forced),
.mode = 0644,
.proc_handler = proc_ipc_dointvec_minmax_orphans,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
{
.procname = "msgmax",
.data = &init_ipc_ns.msg_ctlmax,
.maxlen = sizeof(init_ipc_ns.msg_ctlmax),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_INT_MAX,
},
{
.procname = "msgmni",
.data = &init_ipc_ns.msg_ctlmni,
.maxlen = sizeof(init_ipc_ns.msg_ctlmni),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = &ipc_mni,
},
{
.procname = "auto_msgmni",
.data = NULL,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_ipc_auto_msgmni,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
{
.procname = "msgmnb",
.data = &init_ipc_ns.msg_ctlmnb,
.maxlen = sizeof(init_ipc_ns.msg_ctlmnb),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_INT_MAX,
},
{
.procname = "sem",
.data = &init_ipc_ns.sem_ctls,
.maxlen = 4*sizeof(int),
.mode = 0644,
.proc_handler = proc_ipc_sem_dointvec,
},
#ifdef CONFIG_CHECKPOINT_RESTORE
{
.procname = "sem_next_id",
.data = &init_ipc_ns.ids[IPC_SEM_IDS].next_id,
.maxlen = sizeof(init_ipc_ns.ids[IPC_SEM_IDS].next_id),
.mode = 0444,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_INT_MAX,
},
{
.procname = "msg_next_id",
.data = &init_ipc_ns.ids[IPC_MSG_IDS].next_id,
.maxlen = sizeof(init_ipc_ns.ids[IPC_MSG_IDS].next_id),
.mode = 0444,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_INT_MAX,
},
{
.procname = "shm_next_id",
.data = &init_ipc_ns.ids[IPC_SHM_IDS].next_id,
.maxlen = sizeof(init_ipc_ns.ids[IPC_SHM_IDS].next_id),
.mode = 0444,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_INT_MAX,
},
#endif
{}
};
static struct ctl_table_set *set_lookup(struct ctl_table_root *root)
{
return ¤t->nsproxy->ipc_ns->ipc_set;
}
static int set_is_seen(struct ctl_table_set *set)
{
return ¤t->nsproxy->ipc_ns->ipc_set == set;
}
static int ipc_permissions(struct ctl_table_header *head, struct ctl_table *table)
{
int mode = table->mode;
#ifdef CONFIG_CHECKPOINT_RESTORE
struct ipc_namespace *ns = current->nsproxy->ipc_ns;
if (((table->data == &ns->ids[IPC_SEM_IDS].next_id) ||
(table->data == &ns->ids[IPC_MSG_IDS].next_id) ||
(table->data == &ns->ids[IPC_SHM_IDS].next_id)) &&
checkpoint_restore_ns_capable(ns->user_ns))
mode = 0666;
#endif
return mode;
}
static struct ctl_table_root set_root = {
.lookup = set_lookup,
.permissions = ipc_permissions,
};
bool setup_ipc_sysctls(struct ipc_namespace *ns)
{
struct ctl_table *tbl;
setup_sysctl_set(&ns->ipc_set, &set_root, set_is_seen);
tbl = kmemdup(ipc_sysctls, sizeof(ipc_sysctls), GFP_KERNEL);
if (tbl) {
int i;
for (i = 0; i < ARRAY_SIZE(ipc_sysctls); i++) {
if (tbl[i].data == &init_ipc_ns.shm_ctlmax)
tbl[i].data = &ns->shm_ctlmax;
else if (tbl[i].data == &init_ipc_ns.shm_ctlall)
tbl[i].data = &ns->shm_ctlall;
else if (tbl[i].data == &init_ipc_ns.shm_ctlmni)
tbl[i].data = &ns->shm_ctlmni;
else if (tbl[i].data == &init_ipc_ns.shm_rmid_forced)
tbl[i].data = &ns->shm_rmid_forced;
else if (tbl[i].data == &init_ipc_ns.msg_ctlmax)
tbl[i].data = &ns->msg_ctlmax;
else if (tbl[i].data == &init_ipc_ns.msg_ctlmni)
tbl[i].data = &ns->msg_ctlmni;
else if (tbl[i].data == &init_ipc_ns.msg_ctlmnb)
tbl[i].data = &ns->msg_ctlmnb;
else if (tbl[i].data == &init_ipc_ns.sem_ctls)
tbl[i].data = &ns->sem_ctls;
#ifdef CONFIG_CHECKPOINT_RESTORE
else if (tbl[i].data == &init_ipc_ns.ids[IPC_SEM_IDS].next_id)
tbl[i].data = &ns->ids[IPC_SEM_IDS].next_id;
else if (tbl[i].data == &init_ipc_ns.ids[IPC_MSG_IDS].next_id)
tbl[i].data = &ns->ids[IPC_MSG_IDS].next_id;
else if (tbl[i].data == &init_ipc_ns.ids[IPC_SHM_IDS].next_id)
tbl[i].data = &ns->ids[IPC_SHM_IDS].next_id;
#endif
else
tbl[i].data = NULL;
}
ns->ipc_sysctls = __register_sysctl_table(&ns->ipc_set,
"kernel", tbl,
ARRAY_SIZE(ipc_sysctls));
}
if (!ns->ipc_sysctls) {
kfree(tbl);
retire_sysctl_set(&ns->ipc_set);
return false;
}
return true;
}
void retire_ipc_sysctls(struct ipc_namespace *ns)
{
struct ctl_table *tbl;
tbl = ns->ipc_sysctls->ctl_table_arg;
unregister_sysctl_table(ns->ipc_sysctls);
retire_sysctl_set(&ns->ipc_set);
kfree(tbl);
}
static int __init ipc_sysctl_init(void)
{
if (!setup_ipc_sysctls(&init_ipc_ns)) {
pr_warn("ipc sysctl registration failed\n");
return -ENOMEM;
}
return 0;
}
device_initcall(ipc_sysctl_init);
static int __init ipc_mni_extend(char *str)
{
ipc_mni = IPCMNI_EXTEND;
ipc_mni_shift = IPCMNI_EXTEND_SHIFT;
ipc_min_cycle = IPCMNI_EXTEND_MIN_CYCLE;
pr_info("IPCMNI extended to %d.\n", ipc_mni);
return 0;
}
early_param("ipcmni_extend", ipc_mni_extend);
| linux-master | ipc/ipc_sysctl.c |
// SPDX-License-Identifier: GPL-2.0
/*
* sys_ipc() is the old de-multiplexer for the SysV IPC calls.
*
* This is really horribly ugly, and new architectures should just wire up
* the individual syscalls instead.
*/
#include <linux/unistd.h>
#include <linux/syscalls.h>
#include <linux/security.h>
#include <linux/ipc_namespace.h>
#include "util.h"
#ifdef __ARCH_WANT_SYS_IPC
#include <linux/errno.h>
#include <linux/ipc.h>
#include <linux/shm.h>
#include <linux/uaccess.h>
int ksys_ipc(unsigned int call, int first, unsigned long second,
unsigned long third, void __user * ptr, long fifth)
{
int version, ret;
version = call >> 16; /* hack for backward compatibility */
call &= 0xffff;
switch (call) {
case SEMOP:
return ksys_semtimedop(first, (struct sembuf __user *)ptr,
second, NULL);
case SEMTIMEDOP:
if (IS_ENABLED(CONFIG_64BIT))
return ksys_semtimedop(first, ptr, second,
(const struct __kernel_timespec __user *)fifth);
else if (IS_ENABLED(CONFIG_COMPAT_32BIT_TIME))
return compat_ksys_semtimedop(first, ptr, second,
(const struct old_timespec32 __user *)fifth);
else
return -ENOSYS;
case SEMGET:
return ksys_semget(first, second, third);
case SEMCTL: {
unsigned long arg;
if (!ptr)
return -EINVAL;
if (get_user(arg, (unsigned long __user *) ptr))
return -EFAULT;
return ksys_old_semctl(first, second, third, arg);
}
case MSGSND:
return ksys_msgsnd(first, (struct msgbuf __user *) ptr,
second, third);
case MSGRCV:
switch (version) {
case 0: {
struct ipc_kludge tmp;
if (!ptr)
return -EINVAL;
if (copy_from_user(&tmp,
(struct ipc_kludge __user *) ptr,
sizeof(tmp)))
return -EFAULT;
return ksys_msgrcv(first, tmp.msgp, second,
tmp.msgtyp, third);
}
default:
return ksys_msgrcv(first,
(struct msgbuf __user *) ptr,
second, fifth, third);
}
case MSGGET:
return ksys_msgget((key_t) first, second);
case MSGCTL:
return ksys_old_msgctl(first, second,
(struct msqid_ds __user *)ptr);
case SHMAT:
switch (version) {
default: {
unsigned long raddr;
ret = do_shmat(first, (char __user *)ptr,
second, &raddr, SHMLBA);
if (ret)
return ret;
return put_user(raddr, (unsigned long __user *) third);
}
case 1:
/*
* This was the entry point for kernel-originating calls
* from iBCS2 in 2.2 days.
*/
return -EINVAL;
}
case SHMDT:
return ksys_shmdt((char __user *)ptr);
case SHMGET:
return ksys_shmget(first, second, third);
case SHMCTL:
return ksys_old_shmctl(first, second,
(struct shmid_ds __user *) ptr);
default:
return -ENOSYS;
}
}
SYSCALL_DEFINE6(ipc, unsigned int, call, int, first, unsigned long, second,
unsigned long, third, void __user *, ptr, long, fifth)
{
return ksys_ipc(call, first, second, third, ptr, fifth);
}
#endif
#ifdef CONFIG_COMPAT
#include <linux/compat.h>
#ifndef COMPAT_SHMLBA
#define COMPAT_SHMLBA SHMLBA
#endif
struct compat_ipc_kludge {
compat_uptr_t msgp;
compat_long_t msgtyp;
};
#ifdef CONFIG_ARCH_WANT_OLD_COMPAT_IPC
int compat_ksys_ipc(u32 call, int first, int second,
u32 third, compat_uptr_t ptr, u32 fifth)
{
int version;
u32 pad;
version = call >> 16; /* hack for backward compatibility */
call &= 0xffff;
switch (call) {
case SEMOP:
/* struct sembuf is the same on 32 and 64bit :)) */
return ksys_semtimedop(first, compat_ptr(ptr), second, NULL);
case SEMTIMEDOP:
if (!IS_ENABLED(CONFIG_COMPAT_32BIT_TIME))
return -ENOSYS;
return compat_ksys_semtimedop(first, compat_ptr(ptr), second,
compat_ptr(fifth));
case SEMGET:
return ksys_semget(first, second, third);
case SEMCTL:
if (!ptr)
return -EINVAL;
if (get_user(pad, (u32 __user *) compat_ptr(ptr)))
return -EFAULT;
return compat_ksys_old_semctl(first, second, third, pad);
case MSGSND:
return compat_ksys_msgsnd(first, ptr, second, third);
case MSGRCV: {
void __user *uptr = compat_ptr(ptr);
if (first < 0 || second < 0)
return -EINVAL;
if (!version) {
struct compat_ipc_kludge ipck;
if (!uptr)
return -EINVAL;
if (copy_from_user(&ipck, uptr, sizeof(ipck)))
return -EFAULT;
return compat_ksys_msgrcv(first, ipck.msgp, second,
ipck.msgtyp, third);
}
return compat_ksys_msgrcv(first, ptr, second, fifth, third);
}
case MSGGET:
return ksys_msgget(first, second);
case MSGCTL:
return compat_ksys_old_msgctl(first, second, compat_ptr(ptr));
case SHMAT: {
int err;
unsigned long raddr;
if (version == 1)
return -EINVAL;
err = do_shmat(first, compat_ptr(ptr), second, &raddr,
COMPAT_SHMLBA);
if (err < 0)
return err;
return put_user(raddr, (compat_ulong_t __user *)compat_ptr(third));
}
case SHMDT:
return ksys_shmdt(compat_ptr(ptr));
case SHMGET:
return ksys_shmget(first, (unsigned int)second, third);
case SHMCTL:
return compat_ksys_old_shmctl(first, second, compat_ptr(ptr));
}
return -ENOSYS;
}
COMPAT_SYSCALL_DEFINE6(ipc, u32, call, int, first, int, second,
u32, third, compat_uptr_t, ptr, u32, fifth)
{
return compat_ksys_ipc(call, first, second, third, ptr, fifth);
}
#endif
#endif
| linux-master | ipc/syscall.c |
// SPDX-License-Identifier: GPL-2.0
/*
* linux/ipc/sem.c
* Copyright (C) 1992 Krishna Balasubramanian
* Copyright (C) 1995 Eric Schenk, Bruno Haible
*
* /proc/sysvipc/sem support (c) 1999 Dragos Acostachioaie <[email protected]>
*
* SMP-threaded, sysctl's added
* (c) 1999 Manfred Spraul <[email protected]>
* Enforced range limit on SEM_UNDO
* (c) 2001 Red Hat Inc
* Lockless wakeup
* (c) 2003 Manfred Spraul <[email protected]>
* (c) 2016 Davidlohr Bueso <[email protected]>
* Further wakeup optimizations, documentation
* (c) 2010 Manfred Spraul <[email protected]>
*
* support for audit of ipc object properties and permission changes
* Dustin Kirkland <[email protected]>
*
* namespaces support
* OpenVZ, SWsoft Inc.
* Pavel Emelianov <[email protected]>
*
* Implementation notes: (May 2010)
* This file implements System V semaphores.
*
* User space visible behavior:
* - FIFO ordering for semop() operations (just FIFO, not starvation
* protection)
* - multiple semaphore operations that alter the same semaphore in
* one semop() are handled.
* - sem_ctime (time of last semctl()) is updated in the IPC_SET, SETVAL and
* SETALL calls.
* - two Linux specific semctl() commands: SEM_STAT, SEM_INFO.
* - undo adjustments at process exit are limited to 0..SEMVMX.
* - namespace are supported.
* - SEMMSL, SEMMNS, SEMOPM and SEMMNI can be configured at runtime by writing
* to /proc/sys/kernel/sem.
* - statistics about the usage are reported in /proc/sysvipc/sem.
*
* Internals:
* - scalability:
* - all global variables are read-mostly.
* - semop() calls and semctl(RMID) are synchronized by RCU.
* - most operations do write operations (actually: spin_lock calls) to
* the per-semaphore array structure.
* Thus: Perfect SMP scaling between independent semaphore arrays.
* If multiple semaphores in one array are used, then cache line
* trashing on the semaphore array spinlock will limit the scaling.
* - semncnt and semzcnt are calculated on demand in count_semcnt()
* - the task that performs a successful semop() scans the list of all
* sleeping tasks and completes any pending operations that can be fulfilled.
* Semaphores are actively given to waiting tasks (necessary for FIFO).
* (see update_queue())
* - To improve the scalability, the actual wake-up calls are performed after
* dropping all locks. (see wake_up_sem_queue_prepare())
* - All work is done by the waker, the woken up task does not have to do
* anything - not even acquiring a lock or dropping a refcount.
* - A woken up task may not even touch the semaphore array anymore, it may
* have been destroyed already by a semctl(RMID).
* - UNDO values are stored in an array (one per process and per
* semaphore array, lazily allocated). For backwards compatibility, multiple
* modes for the UNDO variables are supported (per process, per thread)
* (see copy_semundo, CLONE_SYSVSEM)
* - There are two lists of the pending operations: a per-array list
* and per-semaphore list (stored in the array). This allows to achieve FIFO
* ordering without always scanning all pending operations.
* The worst-case behavior is nevertheless O(N^2) for N wakeups.
*/
#include <linux/compat.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
#include <linux/time.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/audit.h>
#include <linux/capability.h>
#include <linux/seq_file.h>
#include <linux/rwsem.h>
#include <linux/nsproxy.h>
#include <linux/ipc_namespace.h>
#include <linux/sched/wake_q.h>
#include <linux/nospec.h>
#include <linux/rhashtable.h>
#include <linux/uaccess.h>
#include "util.h"
/* One semaphore structure for each semaphore in the system. */
struct sem {
int semval; /* current value */
/*
* PID of the process that last modified the semaphore. For
* Linux, specifically these are:
* - semop
* - semctl, via SETVAL and SETALL.
* - at task exit when performing undo adjustments (see exit_sem).
*/
struct pid *sempid;
spinlock_t lock; /* spinlock for fine-grained semtimedop */
struct list_head pending_alter; /* pending single-sop operations */
/* that alter the semaphore */
struct list_head pending_const; /* pending single-sop operations */
/* that do not alter the semaphore*/
time64_t sem_otime; /* candidate for sem_otime */
} ____cacheline_aligned_in_smp;
/* One sem_array data structure for each set of semaphores in the system. */
struct sem_array {
struct kern_ipc_perm sem_perm; /* permissions .. see ipc.h */
time64_t sem_ctime; /* create/last semctl() time */
struct list_head pending_alter; /* pending operations */
/* that alter the array */
struct list_head pending_const; /* pending complex operations */
/* that do not alter semvals */
struct list_head list_id; /* undo requests on this array */
int sem_nsems; /* no. of semaphores in array */
int complex_count; /* pending complex operations */
unsigned int use_global_lock;/* >0: global lock required */
struct sem sems[];
} __randomize_layout;
/* One queue for each sleeping process in the system. */
struct sem_queue {
struct list_head list; /* queue of pending operations */
struct task_struct *sleeper; /* this process */
struct sem_undo *undo; /* undo structure */
struct pid *pid; /* process id of requesting process */
int status; /* completion status of operation */
struct sembuf *sops; /* array of pending operations */
struct sembuf *blocking; /* the operation that blocked */
int nsops; /* number of operations */
bool alter; /* does *sops alter the array? */
bool dupsop; /* sops on more than one sem_num */
};
/* Each task has a list of undo requests. They are executed automatically
* when the process exits.
*/
struct sem_undo {
struct list_head list_proc; /* per-process list: *
* all undos from one process
* rcu protected */
struct rcu_head rcu; /* rcu struct for sem_undo */
struct sem_undo_list *ulp; /* back ptr to sem_undo_list */
struct list_head list_id; /* per semaphore array list:
* all undos for one array */
int semid; /* semaphore set identifier */
short semadj[]; /* array of adjustments */
/* one per semaphore */
};
/* sem_undo_list controls shared access to the list of sem_undo structures
* that may be shared among all a CLONE_SYSVSEM task group.
*/
struct sem_undo_list {
refcount_t refcnt;
spinlock_t lock;
struct list_head list_proc;
};
#define sem_ids(ns) ((ns)->ids[IPC_SEM_IDS])
static int newary(struct ipc_namespace *, struct ipc_params *);
static void freeary(struct ipc_namespace *, struct kern_ipc_perm *);
#ifdef CONFIG_PROC_FS
static int sysvipc_sem_proc_show(struct seq_file *s, void *it);
#endif
#define SEMMSL_FAST 256 /* 512 bytes on stack */
#define SEMOPM_FAST 64 /* ~ 372 bytes on stack */
/*
* Switching from the mode suitable for simple ops
* to the mode for complex ops is costly. Therefore:
* use some hysteresis
*/
#define USE_GLOBAL_LOCK_HYSTERESIS 10
/*
* Locking:
* a) global sem_lock() for read/write
* sem_undo.id_next,
* sem_array.complex_count,
* sem_array.pending{_alter,_const},
* sem_array.sem_undo
*
* b) global or semaphore sem_lock() for read/write:
* sem_array.sems[i].pending_{const,alter}:
*
* c) special:
* sem_undo_list.list_proc:
* * undo_list->lock for write
* * rcu for read
* use_global_lock:
* * global sem_lock() for write
* * either local or global sem_lock() for read.
*
* Memory ordering:
* Most ordering is enforced by using spin_lock() and spin_unlock().
*
* Exceptions:
* 1) use_global_lock: (SEM_BARRIER_1)
* Setting it from non-zero to 0 is a RELEASE, this is ensured by
* using smp_store_release(): Immediately after setting it to 0,
* a simple op can start.
* Testing if it is non-zero is an ACQUIRE, this is ensured by using
* smp_load_acquire().
* Setting it from 0 to non-zero must be ordered with regards to
* this smp_load_acquire(), this is guaranteed because the smp_load_acquire()
* is inside a spin_lock() and after a write from 0 to non-zero a
* spin_lock()+spin_unlock() is done.
* To prevent the compiler/cpu temporarily writing 0 to use_global_lock,
* READ_ONCE()/WRITE_ONCE() is used.
*
* 2) queue.status: (SEM_BARRIER_2)
* Initialization is done while holding sem_lock(), so no further barrier is
* required.
* Setting it to a result code is a RELEASE, this is ensured by both a
* smp_store_release() (for case a) and while holding sem_lock()
* (for case b).
* The ACQUIRE when reading the result code without holding sem_lock() is
* achieved by using READ_ONCE() + smp_acquire__after_ctrl_dep().
* (case a above).
* Reading the result code while holding sem_lock() needs no further barriers,
* the locks inside sem_lock() enforce ordering (case b above)
*
* 3) current->state:
* current->state is set to TASK_INTERRUPTIBLE while holding sem_lock().
* The wakeup is handled using the wake_q infrastructure. wake_q wakeups may
* happen immediately after calling wake_q_add. As wake_q_add_safe() is called
* when holding sem_lock(), no further barriers are required.
*
* See also ipc/mqueue.c for more details on the covered races.
*/
#define sc_semmsl sem_ctls[0]
#define sc_semmns sem_ctls[1]
#define sc_semopm sem_ctls[2]
#define sc_semmni sem_ctls[3]
void sem_init_ns(struct ipc_namespace *ns)
{
ns->sc_semmsl = SEMMSL;
ns->sc_semmns = SEMMNS;
ns->sc_semopm = SEMOPM;
ns->sc_semmni = SEMMNI;
ns->used_sems = 0;
ipc_init_ids(&ns->ids[IPC_SEM_IDS]);
}
#ifdef CONFIG_IPC_NS
void sem_exit_ns(struct ipc_namespace *ns)
{
free_ipcs(ns, &sem_ids(ns), freeary);
idr_destroy(&ns->ids[IPC_SEM_IDS].ipcs_idr);
rhashtable_destroy(&ns->ids[IPC_SEM_IDS].key_ht);
}
#endif
void __init sem_init(void)
{
sem_init_ns(&init_ipc_ns);
ipc_init_proc_interface("sysvipc/sem",
" key semid perms nsems uid gid cuid cgid otime ctime\n",
IPC_SEM_IDS, sysvipc_sem_proc_show);
}
/**
* unmerge_queues - unmerge queues, if possible.
* @sma: semaphore array
*
* The function unmerges the wait queues if complex_count is 0.
* It must be called prior to dropping the global semaphore array lock.
*/
static void unmerge_queues(struct sem_array *sma)
{
struct sem_queue *q, *tq;
/* complex operations still around? */
if (sma->complex_count)
return;
/*
* We will switch back to simple mode.
* Move all pending operation back into the per-semaphore
* queues.
*/
list_for_each_entry_safe(q, tq, &sma->pending_alter, list) {
struct sem *curr;
curr = &sma->sems[q->sops[0].sem_num];
list_add_tail(&q->list, &curr->pending_alter);
}
INIT_LIST_HEAD(&sma->pending_alter);
}
/**
* merge_queues - merge single semop queues into global queue
* @sma: semaphore array
*
* This function merges all per-semaphore queues into the global queue.
* It is necessary to achieve FIFO ordering for the pending single-sop
* operations when a multi-semop operation must sleep.
* Only the alter operations must be moved, the const operations can stay.
*/
static void merge_queues(struct sem_array *sma)
{
int i;
for (i = 0; i < sma->sem_nsems; i++) {
struct sem *sem = &sma->sems[i];
list_splice_init(&sem->pending_alter, &sma->pending_alter);
}
}
static void sem_rcu_free(struct rcu_head *head)
{
struct kern_ipc_perm *p = container_of(head, struct kern_ipc_perm, rcu);
struct sem_array *sma = container_of(p, struct sem_array, sem_perm);
security_sem_free(&sma->sem_perm);
kvfree(sma);
}
/*
* Enter the mode suitable for non-simple operations:
* Caller must own sem_perm.lock.
*/
static void complexmode_enter(struct sem_array *sma)
{
int i;
struct sem *sem;
if (sma->use_global_lock > 0) {
/*
* We are already in global lock mode.
* Nothing to do, just reset the
* counter until we return to simple mode.
*/
WRITE_ONCE(sma->use_global_lock, USE_GLOBAL_LOCK_HYSTERESIS);
return;
}
WRITE_ONCE(sma->use_global_lock, USE_GLOBAL_LOCK_HYSTERESIS);
for (i = 0; i < sma->sem_nsems; i++) {
sem = &sma->sems[i];
spin_lock(&sem->lock);
spin_unlock(&sem->lock);
}
}
/*
* Try to leave the mode that disallows simple operations:
* Caller must own sem_perm.lock.
*/
static void complexmode_tryleave(struct sem_array *sma)
{
if (sma->complex_count) {
/* Complex ops are sleeping.
* We must stay in complex mode
*/
return;
}
if (sma->use_global_lock == 1) {
/* See SEM_BARRIER_1 for purpose/pairing */
smp_store_release(&sma->use_global_lock, 0);
} else {
WRITE_ONCE(sma->use_global_lock,
sma->use_global_lock-1);
}
}
#define SEM_GLOBAL_LOCK (-1)
/*
* If the request contains only one semaphore operation, and there are
* no complex transactions pending, lock only the semaphore involved.
* Otherwise, lock the entire semaphore array, since we either have
* multiple semaphores in our own semops, or we need to look at
* semaphores from other pending complex operations.
*/
static inline int sem_lock(struct sem_array *sma, struct sembuf *sops,
int nsops)
{
struct sem *sem;
int idx;
if (nsops != 1) {
/* Complex operation - acquire a full lock */
ipc_lock_object(&sma->sem_perm);
/* Prevent parallel simple ops */
complexmode_enter(sma);
return SEM_GLOBAL_LOCK;
}
/*
* Only one semaphore affected - try to optimize locking.
* Optimized locking is possible if no complex operation
* is either enqueued or processed right now.
*
* Both facts are tracked by use_global_mode.
*/
idx = array_index_nospec(sops->sem_num, sma->sem_nsems);
sem = &sma->sems[idx];
/*
* Initial check for use_global_lock. Just an optimization,
* no locking, no memory barrier.
*/
if (!READ_ONCE(sma->use_global_lock)) {
/*
* It appears that no complex operation is around.
* Acquire the per-semaphore lock.
*/
spin_lock(&sem->lock);
/* see SEM_BARRIER_1 for purpose/pairing */
if (!smp_load_acquire(&sma->use_global_lock)) {
/* fast path successful! */
return sops->sem_num;
}
spin_unlock(&sem->lock);
}
/* slow path: acquire the full lock */
ipc_lock_object(&sma->sem_perm);
if (sma->use_global_lock == 0) {
/*
* The use_global_lock mode ended while we waited for
* sma->sem_perm.lock. Thus we must switch to locking
* with sem->lock.
* Unlike in the fast path, there is no need to recheck
* sma->use_global_lock after we have acquired sem->lock:
* We own sma->sem_perm.lock, thus use_global_lock cannot
* change.
*/
spin_lock(&sem->lock);
ipc_unlock_object(&sma->sem_perm);
return sops->sem_num;
} else {
/*
* Not a false alarm, thus continue to use the global lock
* mode. No need for complexmode_enter(), this was done by
* the caller that has set use_global_mode to non-zero.
*/
return SEM_GLOBAL_LOCK;
}
}
static inline void sem_unlock(struct sem_array *sma, int locknum)
{
if (locknum == SEM_GLOBAL_LOCK) {
unmerge_queues(sma);
complexmode_tryleave(sma);
ipc_unlock_object(&sma->sem_perm);
} else {
struct sem *sem = &sma->sems[locknum];
spin_unlock(&sem->lock);
}
}
/*
* sem_lock_(check_) routines are called in the paths where the rwsem
* is not held.
*
* The caller holds the RCU read lock.
*/
static inline struct sem_array *sem_obtain_object(struct ipc_namespace *ns, int id)
{
struct kern_ipc_perm *ipcp = ipc_obtain_object_idr(&sem_ids(ns), id);
if (IS_ERR(ipcp))
return ERR_CAST(ipcp);
return container_of(ipcp, struct sem_array, sem_perm);
}
static inline struct sem_array *sem_obtain_object_check(struct ipc_namespace *ns,
int id)
{
struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&sem_ids(ns), id);
if (IS_ERR(ipcp))
return ERR_CAST(ipcp);
return container_of(ipcp, struct sem_array, sem_perm);
}
static inline void sem_lock_and_putref(struct sem_array *sma)
{
sem_lock(sma, NULL, -1);
ipc_rcu_putref(&sma->sem_perm, sem_rcu_free);
}
static inline void sem_rmid(struct ipc_namespace *ns, struct sem_array *s)
{
ipc_rmid(&sem_ids(ns), &s->sem_perm);
}
static struct sem_array *sem_alloc(size_t nsems)
{
struct sem_array *sma;
if (nsems > (INT_MAX - sizeof(*sma)) / sizeof(sma->sems[0]))
return NULL;
sma = kvzalloc(struct_size(sma, sems, nsems), GFP_KERNEL_ACCOUNT);
if (unlikely(!sma))
return NULL;
return sma;
}
/**
* newary - Create a new semaphore set
* @ns: namespace
* @params: ptr to the structure that contains key, semflg and nsems
*
* Called with sem_ids.rwsem held (as a writer)
*/
static int newary(struct ipc_namespace *ns, struct ipc_params *params)
{
int retval;
struct sem_array *sma;
key_t key = params->key;
int nsems = params->u.nsems;
int semflg = params->flg;
int i;
if (!nsems)
return -EINVAL;
if (ns->used_sems + nsems > ns->sc_semmns)
return -ENOSPC;
sma = sem_alloc(nsems);
if (!sma)
return -ENOMEM;
sma->sem_perm.mode = (semflg & S_IRWXUGO);
sma->sem_perm.key = key;
sma->sem_perm.security = NULL;
retval = security_sem_alloc(&sma->sem_perm);
if (retval) {
kvfree(sma);
return retval;
}
for (i = 0; i < nsems; i++) {
INIT_LIST_HEAD(&sma->sems[i].pending_alter);
INIT_LIST_HEAD(&sma->sems[i].pending_const);
spin_lock_init(&sma->sems[i].lock);
}
sma->complex_count = 0;
sma->use_global_lock = USE_GLOBAL_LOCK_HYSTERESIS;
INIT_LIST_HEAD(&sma->pending_alter);
INIT_LIST_HEAD(&sma->pending_const);
INIT_LIST_HEAD(&sma->list_id);
sma->sem_nsems = nsems;
sma->sem_ctime = ktime_get_real_seconds();
/* ipc_addid() locks sma upon success. */
retval = ipc_addid(&sem_ids(ns), &sma->sem_perm, ns->sc_semmni);
if (retval < 0) {
ipc_rcu_putref(&sma->sem_perm, sem_rcu_free);
return retval;
}
ns->used_sems += nsems;
sem_unlock(sma, -1);
rcu_read_unlock();
return sma->sem_perm.id;
}
/*
* Called with sem_ids.rwsem and ipcp locked.
*/
static int sem_more_checks(struct kern_ipc_perm *ipcp, struct ipc_params *params)
{
struct sem_array *sma;
sma = container_of(ipcp, struct sem_array, sem_perm);
if (params->u.nsems > sma->sem_nsems)
return -EINVAL;
return 0;
}
long ksys_semget(key_t key, int nsems, int semflg)
{
struct ipc_namespace *ns;
static const struct ipc_ops sem_ops = {
.getnew = newary,
.associate = security_sem_associate,
.more_checks = sem_more_checks,
};
struct ipc_params sem_params;
ns = current->nsproxy->ipc_ns;
if (nsems < 0 || nsems > ns->sc_semmsl)
return -EINVAL;
sem_params.key = key;
sem_params.flg = semflg;
sem_params.u.nsems = nsems;
return ipcget(ns, &sem_ids(ns), &sem_ops, &sem_params);
}
SYSCALL_DEFINE3(semget, key_t, key, int, nsems, int, semflg)
{
return ksys_semget(key, nsems, semflg);
}
/**
* perform_atomic_semop[_slow] - Attempt to perform semaphore
* operations on a given array.
* @sma: semaphore array
* @q: struct sem_queue that describes the operation
*
* Caller blocking are as follows, based the value
* indicated by the semaphore operation (sem_op):
*
* (1) >0 never blocks.
* (2) 0 (wait-for-zero operation): semval is non-zero.
* (3) <0 attempting to decrement semval to a value smaller than zero.
*
* Returns 0 if the operation was possible.
* Returns 1 if the operation is impossible, the caller must sleep.
* Returns <0 for error codes.
*/
static int perform_atomic_semop_slow(struct sem_array *sma, struct sem_queue *q)
{
int result, sem_op, nsops;
struct pid *pid;
struct sembuf *sop;
struct sem *curr;
struct sembuf *sops;
struct sem_undo *un;
sops = q->sops;
nsops = q->nsops;
un = q->undo;
for (sop = sops; sop < sops + nsops; sop++) {
int idx = array_index_nospec(sop->sem_num, sma->sem_nsems);
curr = &sma->sems[idx];
sem_op = sop->sem_op;
result = curr->semval;
if (!sem_op && result)
goto would_block;
result += sem_op;
if (result < 0)
goto would_block;
if (result > SEMVMX)
goto out_of_range;
if (sop->sem_flg & SEM_UNDO) {
int undo = un->semadj[sop->sem_num] - sem_op;
/* Exceeding the undo range is an error. */
if (undo < (-SEMAEM - 1) || undo > SEMAEM)
goto out_of_range;
un->semadj[sop->sem_num] = undo;
}
curr->semval = result;
}
sop--;
pid = q->pid;
while (sop >= sops) {
ipc_update_pid(&sma->sems[sop->sem_num].sempid, pid);
sop--;
}
return 0;
out_of_range:
result = -ERANGE;
goto undo;
would_block:
q->blocking = sop;
if (sop->sem_flg & IPC_NOWAIT)
result = -EAGAIN;
else
result = 1;
undo:
sop--;
while (sop >= sops) {
sem_op = sop->sem_op;
sma->sems[sop->sem_num].semval -= sem_op;
if (sop->sem_flg & SEM_UNDO)
un->semadj[sop->sem_num] += sem_op;
sop--;
}
return result;
}
static int perform_atomic_semop(struct sem_array *sma, struct sem_queue *q)
{
int result, sem_op, nsops;
struct sembuf *sop;
struct sem *curr;
struct sembuf *sops;
struct sem_undo *un;
sops = q->sops;
nsops = q->nsops;
un = q->undo;
if (unlikely(q->dupsop))
return perform_atomic_semop_slow(sma, q);
/*
* We scan the semaphore set twice, first to ensure that the entire
* operation can succeed, therefore avoiding any pointless writes
* to shared memory and having to undo such changes in order to block
* until the operations can go through.
*/
for (sop = sops; sop < sops + nsops; sop++) {
int idx = array_index_nospec(sop->sem_num, sma->sem_nsems);
curr = &sma->sems[idx];
sem_op = sop->sem_op;
result = curr->semval;
if (!sem_op && result)
goto would_block; /* wait-for-zero */
result += sem_op;
if (result < 0)
goto would_block;
if (result > SEMVMX)
return -ERANGE;
if (sop->sem_flg & SEM_UNDO) {
int undo = un->semadj[sop->sem_num] - sem_op;
/* Exceeding the undo range is an error. */
if (undo < (-SEMAEM - 1) || undo > SEMAEM)
return -ERANGE;
}
}
for (sop = sops; sop < sops + nsops; sop++) {
curr = &sma->sems[sop->sem_num];
sem_op = sop->sem_op;
if (sop->sem_flg & SEM_UNDO) {
int undo = un->semadj[sop->sem_num] - sem_op;
un->semadj[sop->sem_num] = undo;
}
curr->semval += sem_op;
ipc_update_pid(&curr->sempid, q->pid);
}
return 0;
would_block:
q->blocking = sop;
return sop->sem_flg & IPC_NOWAIT ? -EAGAIN : 1;
}
static inline void wake_up_sem_queue_prepare(struct sem_queue *q, int error,
struct wake_q_head *wake_q)
{
struct task_struct *sleeper;
sleeper = get_task_struct(q->sleeper);
/* see SEM_BARRIER_2 for purpose/pairing */
smp_store_release(&q->status, error);
wake_q_add_safe(wake_q, sleeper);
}
static void unlink_queue(struct sem_array *sma, struct sem_queue *q)
{
list_del(&q->list);
if (q->nsops > 1)
sma->complex_count--;
}
/** check_restart(sma, q)
* @sma: semaphore array
* @q: the operation that just completed
*
* update_queue is O(N^2) when it restarts scanning the whole queue of
* waiting operations. Therefore this function checks if the restart is
* really necessary. It is called after a previously waiting operation
* modified the array.
* Note that wait-for-zero operations are handled without restart.
*/
static inline int check_restart(struct sem_array *sma, struct sem_queue *q)
{
/* pending complex alter operations are too difficult to analyse */
if (!list_empty(&sma->pending_alter))
return 1;
/* we were a sleeping complex operation. Too difficult */
if (q->nsops > 1)
return 1;
/* It is impossible that someone waits for the new value:
* - complex operations always restart.
* - wait-for-zero are handled separately.
* - q is a previously sleeping simple operation that
* altered the array. It must be a decrement, because
* simple increments never sleep.
* - If there are older (higher priority) decrements
* in the queue, then they have observed the original
* semval value and couldn't proceed. The operation
* decremented to value - thus they won't proceed either.
*/
return 0;
}
/**
* wake_const_ops - wake up non-alter tasks
* @sma: semaphore array.
* @semnum: semaphore that was modified.
* @wake_q: lockless wake-queue head.
*
* wake_const_ops must be called after a semaphore in a semaphore array
* was set to 0. If complex const operations are pending, wake_const_ops must
* be called with semnum = -1, as well as with the number of each modified
* semaphore.
* The tasks that must be woken up are added to @wake_q. The return code
* is stored in q->pid.
* The function returns 1 if at least one operation was completed successfully.
*/
static int wake_const_ops(struct sem_array *sma, int semnum,
struct wake_q_head *wake_q)
{
struct sem_queue *q, *tmp;
struct list_head *pending_list;
int semop_completed = 0;
if (semnum == -1)
pending_list = &sma->pending_const;
else
pending_list = &sma->sems[semnum].pending_const;
list_for_each_entry_safe(q, tmp, pending_list, list) {
int error = perform_atomic_semop(sma, q);
if (error > 0)
continue;
/* operation completed, remove from queue & wakeup */
unlink_queue(sma, q);
wake_up_sem_queue_prepare(q, error, wake_q);
if (error == 0)
semop_completed = 1;
}
return semop_completed;
}
/**
* do_smart_wakeup_zero - wakeup all wait for zero tasks
* @sma: semaphore array
* @sops: operations that were performed
* @nsops: number of operations
* @wake_q: lockless wake-queue head
*
* Checks all required queue for wait-for-zero operations, based
* on the actual changes that were performed on the semaphore array.
* The function returns 1 if at least one operation was completed successfully.
*/
static int do_smart_wakeup_zero(struct sem_array *sma, struct sembuf *sops,
int nsops, struct wake_q_head *wake_q)
{
int i;
int semop_completed = 0;
int got_zero = 0;
/* first: the per-semaphore queues, if known */
if (sops) {
for (i = 0; i < nsops; i++) {
int num = sops[i].sem_num;
if (sma->sems[num].semval == 0) {
got_zero = 1;
semop_completed |= wake_const_ops(sma, num, wake_q);
}
}
} else {
/*
* No sops means modified semaphores not known.
* Assume all were changed.
*/
for (i = 0; i < sma->sem_nsems; i++) {
if (sma->sems[i].semval == 0) {
got_zero = 1;
semop_completed |= wake_const_ops(sma, i, wake_q);
}
}
}
/*
* If one of the modified semaphores got 0,
* then check the global queue, too.
*/
if (got_zero)
semop_completed |= wake_const_ops(sma, -1, wake_q);
return semop_completed;
}
/**
* update_queue - look for tasks that can be completed.
* @sma: semaphore array.
* @semnum: semaphore that was modified.
* @wake_q: lockless wake-queue head.
*
* update_queue must be called after a semaphore in a semaphore array
* was modified. If multiple semaphores were modified, update_queue must
* be called with semnum = -1, as well as with the number of each modified
* semaphore.
* The tasks that must be woken up are added to @wake_q. The return code
* is stored in q->pid.
* The function internally checks if const operations can now succeed.
*
* The function return 1 if at least one semop was completed successfully.
*/
static int update_queue(struct sem_array *sma, int semnum, struct wake_q_head *wake_q)
{
struct sem_queue *q, *tmp;
struct list_head *pending_list;
int semop_completed = 0;
if (semnum == -1)
pending_list = &sma->pending_alter;
else
pending_list = &sma->sems[semnum].pending_alter;
again:
list_for_each_entry_safe(q, tmp, pending_list, list) {
int error, restart;
/* If we are scanning the single sop, per-semaphore list of
* one semaphore and that semaphore is 0, then it is not
* necessary to scan further: simple increments
* that affect only one entry succeed immediately and cannot
* be in the per semaphore pending queue, and decrements
* cannot be successful if the value is already 0.
*/
if (semnum != -1 && sma->sems[semnum].semval == 0)
break;
error = perform_atomic_semop(sma, q);
/* Does q->sleeper still need to sleep? */
if (error > 0)
continue;
unlink_queue(sma, q);
if (error) {
restart = 0;
} else {
semop_completed = 1;
do_smart_wakeup_zero(sma, q->sops, q->nsops, wake_q);
restart = check_restart(sma, q);
}
wake_up_sem_queue_prepare(q, error, wake_q);
if (restart)
goto again;
}
return semop_completed;
}
/**
* set_semotime - set sem_otime
* @sma: semaphore array
* @sops: operations that modified the array, may be NULL
*
* sem_otime is replicated to avoid cache line trashing.
* This function sets one instance to the current time.
*/
static void set_semotime(struct sem_array *sma, struct sembuf *sops)
{
if (sops == NULL) {
sma->sems[0].sem_otime = ktime_get_real_seconds();
} else {
sma->sems[sops[0].sem_num].sem_otime =
ktime_get_real_seconds();
}
}
/**
* do_smart_update - optimized update_queue
* @sma: semaphore array
* @sops: operations that were performed
* @nsops: number of operations
* @otime: force setting otime
* @wake_q: lockless wake-queue head
*
* do_smart_update() does the required calls to update_queue and wakeup_zero,
* based on the actual changes that were performed on the semaphore array.
* Note that the function does not do the actual wake-up: the caller is
* responsible for calling wake_up_q().
* It is safe to perform this call after dropping all locks.
*/
static void do_smart_update(struct sem_array *sma, struct sembuf *sops, int nsops,
int otime, struct wake_q_head *wake_q)
{
int i;
otime |= do_smart_wakeup_zero(sma, sops, nsops, wake_q);
if (!list_empty(&sma->pending_alter)) {
/* semaphore array uses the global queue - just process it. */
otime |= update_queue(sma, -1, wake_q);
} else {
if (!sops) {
/*
* No sops, thus the modified semaphores are not
* known. Check all.
*/
for (i = 0; i < sma->sem_nsems; i++)
otime |= update_queue(sma, i, wake_q);
} else {
/*
* Check the semaphores that were increased:
* - No complex ops, thus all sleeping ops are
* decrease.
* - if we decreased the value, then any sleeping
* semaphore ops won't be able to run: If the
* previous value was too small, then the new
* value will be too small, too.
*/
for (i = 0; i < nsops; i++) {
if (sops[i].sem_op > 0) {
otime |= update_queue(sma,
sops[i].sem_num, wake_q);
}
}
}
}
if (otime)
set_semotime(sma, sops);
}
/*
* check_qop: Test if a queued operation sleeps on the semaphore semnum
*/
static int check_qop(struct sem_array *sma, int semnum, struct sem_queue *q,
bool count_zero)
{
struct sembuf *sop = q->blocking;
/*
* Linux always (since 0.99.10) reported a task as sleeping on all
* semaphores. This violates SUS, therefore it was changed to the
* standard compliant behavior.
* Give the administrators a chance to notice that an application
* might misbehave because it relies on the Linux behavior.
*/
pr_info_once("semctl(GETNCNT/GETZCNT) is since 3.16 Single Unix Specification compliant.\n"
"The task %s (%d) triggered the difference, watch for misbehavior.\n",
current->comm, task_pid_nr(current));
if (sop->sem_num != semnum)
return 0;
if (count_zero && sop->sem_op == 0)
return 1;
if (!count_zero && sop->sem_op < 0)
return 1;
return 0;
}
/* The following counts are associated to each semaphore:
* semncnt number of tasks waiting on semval being nonzero
* semzcnt number of tasks waiting on semval being zero
*
* Per definition, a task waits only on the semaphore of the first semop
* that cannot proceed, even if additional operation would block, too.
*/
static int count_semcnt(struct sem_array *sma, ushort semnum,
bool count_zero)
{
struct list_head *l;
struct sem_queue *q;
int semcnt;
semcnt = 0;
/* First: check the simple operations. They are easy to evaluate */
if (count_zero)
l = &sma->sems[semnum].pending_const;
else
l = &sma->sems[semnum].pending_alter;
list_for_each_entry(q, l, list) {
/* all task on a per-semaphore list sleep on exactly
* that semaphore
*/
semcnt++;
}
/* Then: check the complex operations. */
list_for_each_entry(q, &sma->pending_alter, list) {
semcnt += check_qop(sma, semnum, q, count_zero);
}
if (count_zero) {
list_for_each_entry(q, &sma->pending_const, list) {
semcnt += check_qop(sma, semnum, q, count_zero);
}
}
return semcnt;
}
/* Free a semaphore set. freeary() is called with sem_ids.rwsem locked
* as a writer and the spinlock for this semaphore set hold. sem_ids.rwsem
* remains locked on exit.
*/
static void freeary(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
{
struct sem_undo *un, *tu;
struct sem_queue *q, *tq;
struct sem_array *sma = container_of(ipcp, struct sem_array, sem_perm);
int i;
DEFINE_WAKE_Q(wake_q);
/* Free the existing undo structures for this semaphore set. */
ipc_assert_locked_object(&sma->sem_perm);
list_for_each_entry_safe(un, tu, &sma->list_id, list_id) {
list_del(&un->list_id);
spin_lock(&un->ulp->lock);
un->semid = -1;
list_del_rcu(&un->list_proc);
spin_unlock(&un->ulp->lock);
kvfree_rcu(un, rcu);
}
/* Wake up all pending processes and let them fail with EIDRM. */
list_for_each_entry_safe(q, tq, &sma->pending_const, list) {
unlink_queue(sma, q);
wake_up_sem_queue_prepare(q, -EIDRM, &wake_q);
}
list_for_each_entry_safe(q, tq, &sma->pending_alter, list) {
unlink_queue(sma, q);
wake_up_sem_queue_prepare(q, -EIDRM, &wake_q);
}
for (i = 0; i < sma->sem_nsems; i++) {
struct sem *sem = &sma->sems[i];
list_for_each_entry_safe(q, tq, &sem->pending_const, list) {
unlink_queue(sma, q);
wake_up_sem_queue_prepare(q, -EIDRM, &wake_q);
}
list_for_each_entry_safe(q, tq, &sem->pending_alter, list) {
unlink_queue(sma, q);
wake_up_sem_queue_prepare(q, -EIDRM, &wake_q);
}
ipc_update_pid(&sem->sempid, NULL);
}
/* Remove the semaphore set from the IDR */
sem_rmid(ns, sma);
sem_unlock(sma, -1);
rcu_read_unlock();
wake_up_q(&wake_q);
ns->used_sems -= sma->sem_nsems;
ipc_rcu_putref(&sma->sem_perm, sem_rcu_free);
}
static unsigned long copy_semid_to_user(void __user *buf, struct semid64_ds *in, int version)
{
switch (version) {
case IPC_64:
return copy_to_user(buf, in, sizeof(*in));
case IPC_OLD:
{
struct semid_ds out;
memset(&out, 0, sizeof(out));
ipc64_perm_to_ipc_perm(&in->sem_perm, &out.sem_perm);
out.sem_otime = in->sem_otime;
out.sem_ctime = in->sem_ctime;
out.sem_nsems = in->sem_nsems;
return copy_to_user(buf, &out, sizeof(out));
}
default:
return -EINVAL;
}
}
static time64_t get_semotime(struct sem_array *sma)
{
int i;
time64_t res;
res = sma->sems[0].sem_otime;
for (i = 1; i < sma->sem_nsems; i++) {
time64_t to = sma->sems[i].sem_otime;
if (to > res)
res = to;
}
return res;
}
static int semctl_stat(struct ipc_namespace *ns, int semid,
int cmd, struct semid64_ds *semid64)
{
struct sem_array *sma;
time64_t semotime;
int err;
memset(semid64, 0, sizeof(*semid64));
rcu_read_lock();
if (cmd == SEM_STAT || cmd == SEM_STAT_ANY) {
sma = sem_obtain_object(ns, semid);
if (IS_ERR(sma)) {
err = PTR_ERR(sma);
goto out_unlock;
}
} else { /* IPC_STAT */
sma = sem_obtain_object_check(ns, semid);
if (IS_ERR(sma)) {
err = PTR_ERR(sma);
goto out_unlock;
}
}
/* see comment for SHM_STAT_ANY */
if (cmd == SEM_STAT_ANY)
audit_ipc_obj(&sma->sem_perm);
else {
err = -EACCES;
if (ipcperms(ns, &sma->sem_perm, S_IRUGO))
goto out_unlock;
}
err = security_sem_semctl(&sma->sem_perm, cmd);
if (err)
goto out_unlock;
ipc_lock_object(&sma->sem_perm);
if (!ipc_valid_object(&sma->sem_perm)) {
ipc_unlock_object(&sma->sem_perm);
err = -EIDRM;
goto out_unlock;
}
kernel_to_ipc64_perm(&sma->sem_perm, &semid64->sem_perm);
semotime = get_semotime(sma);
semid64->sem_otime = semotime;
semid64->sem_ctime = sma->sem_ctime;
#ifndef CONFIG_64BIT
semid64->sem_otime_high = semotime >> 32;
semid64->sem_ctime_high = sma->sem_ctime >> 32;
#endif
semid64->sem_nsems = sma->sem_nsems;
if (cmd == IPC_STAT) {
/*
* As defined in SUS:
* Return 0 on success
*/
err = 0;
} else {
/*
* SEM_STAT and SEM_STAT_ANY (both Linux specific)
* Return the full id, including the sequence number
*/
err = sma->sem_perm.id;
}
ipc_unlock_object(&sma->sem_perm);
out_unlock:
rcu_read_unlock();
return err;
}
static int semctl_info(struct ipc_namespace *ns, int semid,
int cmd, void __user *p)
{
struct seminfo seminfo;
int max_idx;
int err;
err = security_sem_semctl(NULL, cmd);
if (err)
return err;
memset(&seminfo, 0, sizeof(seminfo));
seminfo.semmni = ns->sc_semmni;
seminfo.semmns = ns->sc_semmns;
seminfo.semmsl = ns->sc_semmsl;
seminfo.semopm = ns->sc_semopm;
seminfo.semvmx = SEMVMX;
seminfo.semmnu = SEMMNU;
seminfo.semmap = SEMMAP;
seminfo.semume = SEMUME;
down_read(&sem_ids(ns).rwsem);
if (cmd == SEM_INFO) {
seminfo.semusz = sem_ids(ns).in_use;
seminfo.semaem = ns->used_sems;
} else {
seminfo.semusz = SEMUSZ;
seminfo.semaem = SEMAEM;
}
max_idx = ipc_get_maxidx(&sem_ids(ns));
up_read(&sem_ids(ns).rwsem);
if (copy_to_user(p, &seminfo, sizeof(struct seminfo)))
return -EFAULT;
return (max_idx < 0) ? 0 : max_idx;
}
static int semctl_setval(struct ipc_namespace *ns, int semid, int semnum,
int val)
{
struct sem_undo *un;
struct sem_array *sma;
struct sem *curr;
int err;
DEFINE_WAKE_Q(wake_q);
if (val > SEMVMX || val < 0)
return -ERANGE;
rcu_read_lock();
sma = sem_obtain_object_check(ns, semid);
if (IS_ERR(sma)) {
rcu_read_unlock();
return PTR_ERR(sma);
}
if (semnum < 0 || semnum >= sma->sem_nsems) {
rcu_read_unlock();
return -EINVAL;
}
if (ipcperms(ns, &sma->sem_perm, S_IWUGO)) {
rcu_read_unlock();
return -EACCES;
}
err = security_sem_semctl(&sma->sem_perm, SETVAL);
if (err) {
rcu_read_unlock();
return -EACCES;
}
sem_lock(sma, NULL, -1);
if (!ipc_valid_object(&sma->sem_perm)) {
sem_unlock(sma, -1);
rcu_read_unlock();
return -EIDRM;
}
semnum = array_index_nospec(semnum, sma->sem_nsems);
curr = &sma->sems[semnum];
ipc_assert_locked_object(&sma->sem_perm);
list_for_each_entry(un, &sma->list_id, list_id)
un->semadj[semnum] = 0;
curr->semval = val;
ipc_update_pid(&curr->sempid, task_tgid(current));
sma->sem_ctime = ktime_get_real_seconds();
/* maybe some queued-up processes were waiting for this */
do_smart_update(sma, NULL, 0, 0, &wake_q);
sem_unlock(sma, -1);
rcu_read_unlock();
wake_up_q(&wake_q);
return 0;
}
static int semctl_main(struct ipc_namespace *ns, int semid, int semnum,
int cmd, void __user *p)
{
struct sem_array *sma;
struct sem *curr;
int err, nsems;
ushort fast_sem_io[SEMMSL_FAST];
ushort *sem_io = fast_sem_io;
DEFINE_WAKE_Q(wake_q);
rcu_read_lock();
sma = sem_obtain_object_check(ns, semid);
if (IS_ERR(sma)) {
rcu_read_unlock();
return PTR_ERR(sma);
}
nsems = sma->sem_nsems;
err = -EACCES;
if (ipcperms(ns, &sma->sem_perm, cmd == SETALL ? S_IWUGO : S_IRUGO))
goto out_rcu_wakeup;
err = security_sem_semctl(&sma->sem_perm, cmd);
if (err)
goto out_rcu_wakeup;
switch (cmd) {
case GETALL:
{
ushort __user *array = p;
int i;
sem_lock(sma, NULL, -1);
if (!ipc_valid_object(&sma->sem_perm)) {
err = -EIDRM;
goto out_unlock;
}
if (nsems > SEMMSL_FAST) {
if (!ipc_rcu_getref(&sma->sem_perm)) {
err = -EIDRM;
goto out_unlock;
}
sem_unlock(sma, -1);
rcu_read_unlock();
sem_io = kvmalloc_array(nsems, sizeof(ushort),
GFP_KERNEL);
if (sem_io == NULL) {
ipc_rcu_putref(&sma->sem_perm, sem_rcu_free);
return -ENOMEM;
}
rcu_read_lock();
sem_lock_and_putref(sma);
if (!ipc_valid_object(&sma->sem_perm)) {
err = -EIDRM;
goto out_unlock;
}
}
for (i = 0; i < sma->sem_nsems; i++)
sem_io[i] = sma->sems[i].semval;
sem_unlock(sma, -1);
rcu_read_unlock();
err = 0;
if (copy_to_user(array, sem_io, nsems*sizeof(ushort)))
err = -EFAULT;
goto out_free;
}
case SETALL:
{
int i;
struct sem_undo *un;
if (!ipc_rcu_getref(&sma->sem_perm)) {
err = -EIDRM;
goto out_rcu_wakeup;
}
rcu_read_unlock();
if (nsems > SEMMSL_FAST) {
sem_io = kvmalloc_array(nsems, sizeof(ushort),
GFP_KERNEL);
if (sem_io == NULL) {
ipc_rcu_putref(&sma->sem_perm, sem_rcu_free);
return -ENOMEM;
}
}
if (copy_from_user(sem_io, p, nsems*sizeof(ushort))) {
ipc_rcu_putref(&sma->sem_perm, sem_rcu_free);
err = -EFAULT;
goto out_free;
}
for (i = 0; i < nsems; i++) {
if (sem_io[i] > SEMVMX) {
ipc_rcu_putref(&sma->sem_perm, sem_rcu_free);
err = -ERANGE;
goto out_free;
}
}
rcu_read_lock();
sem_lock_and_putref(sma);
if (!ipc_valid_object(&sma->sem_perm)) {
err = -EIDRM;
goto out_unlock;
}
for (i = 0; i < nsems; i++) {
sma->sems[i].semval = sem_io[i];
ipc_update_pid(&sma->sems[i].sempid, task_tgid(current));
}
ipc_assert_locked_object(&sma->sem_perm);
list_for_each_entry(un, &sma->list_id, list_id) {
for (i = 0; i < nsems; i++)
un->semadj[i] = 0;
}
sma->sem_ctime = ktime_get_real_seconds();
/* maybe some queued-up processes were waiting for this */
do_smart_update(sma, NULL, 0, 0, &wake_q);
err = 0;
goto out_unlock;
}
/* GETVAL, GETPID, GETNCTN, GETZCNT: fall-through */
}
err = -EINVAL;
if (semnum < 0 || semnum >= nsems)
goto out_rcu_wakeup;
sem_lock(sma, NULL, -1);
if (!ipc_valid_object(&sma->sem_perm)) {
err = -EIDRM;
goto out_unlock;
}
semnum = array_index_nospec(semnum, nsems);
curr = &sma->sems[semnum];
switch (cmd) {
case GETVAL:
err = curr->semval;
goto out_unlock;
case GETPID:
err = pid_vnr(curr->sempid);
goto out_unlock;
case GETNCNT:
err = count_semcnt(sma, semnum, 0);
goto out_unlock;
case GETZCNT:
err = count_semcnt(sma, semnum, 1);
goto out_unlock;
}
out_unlock:
sem_unlock(sma, -1);
out_rcu_wakeup:
rcu_read_unlock();
wake_up_q(&wake_q);
out_free:
if (sem_io != fast_sem_io)
kvfree(sem_io);
return err;
}
static inline unsigned long
copy_semid_from_user(struct semid64_ds *out, void __user *buf, int version)
{
switch (version) {
case IPC_64:
if (copy_from_user(out, buf, sizeof(*out)))
return -EFAULT;
return 0;
case IPC_OLD:
{
struct semid_ds tbuf_old;
if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
return -EFAULT;
out->sem_perm.uid = tbuf_old.sem_perm.uid;
out->sem_perm.gid = tbuf_old.sem_perm.gid;
out->sem_perm.mode = tbuf_old.sem_perm.mode;
return 0;
}
default:
return -EINVAL;
}
}
/*
* This function handles some semctl commands which require the rwsem
* to be held in write mode.
* NOTE: no locks must be held, the rwsem is taken inside this function.
*/
static int semctl_down(struct ipc_namespace *ns, int semid,
int cmd, struct semid64_ds *semid64)
{
struct sem_array *sma;
int err;
struct kern_ipc_perm *ipcp;
down_write(&sem_ids(ns).rwsem);
rcu_read_lock();
ipcp = ipcctl_obtain_check(ns, &sem_ids(ns), semid, cmd,
&semid64->sem_perm, 0);
if (IS_ERR(ipcp)) {
err = PTR_ERR(ipcp);
goto out_unlock1;
}
sma = container_of(ipcp, struct sem_array, sem_perm);
err = security_sem_semctl(&sma->sem_perm, cmd);
if (err)
goto out_unlock1;
switch (cmd) {
case IPC_RMID:
sem_lock(sma, NULL, -1);
/* freeary unlocks the ipc object and rcu */
freeary(ns, ipcp);
goto out_up;
case IPC_SET:
sem_lock(sma, NULL, -1);
err = ipc_update_perm(&semid64->sem_perm, ipcp);
if (err)
goto out_unlock0;
sma->sem_ctime = ktime_get_real_seconds();
break;
default:
err = -EINVAL;
goto out_unlock1;
}
out_unlock0:
sem_unlock(sma, -1);
out_unlock1:
rcu_read_unlock();
out_up:
up_write(&sem_ids(ns).rwsem);
return err;
}
static long ksys_semctl(int semid, int semnum, int cmd, unsigned long arg, int version)
{
struct ipc_namespace *ns;
void __user *p = (void __user *)arg;
struct semid64_ds semid64;
int err;
if (semid < 0)
return -EINVAL;
ns = current->nsproxy->ipc_ns;
switch (cmd) {
case IPC_INFO:
case SEM_INFO:
return semctl_info(ns, semid, cmd, p);
case IPC_STAT:
case SEM_STAT:
case SEM_STAT_ANY:
err = semctl_stat(ns, semid, cmd, &semid64);
if (err < 0)
return err;
if (copy_semid_to_user(p, &semid64, version))
err = -EFAULT;
return err;
case GETALL:
case GETVAL:
case GETPID:
case GETNCNT:
case GETZCNT:
case SETALL:
return semctl_main(ns, semid, semnum, cmd, p);
case SETVAL: {
int val;
#if defined(CONFIG_64BIT) && defined(__BIG_ENDIAN)
/* big-endian 64bit */
val = arg >> 32;
#else
/* 32bit or little-endian 64bit */
val = arg;
#endif
return semctl_setval(ns, semid, semnum, val);
}
case IPC_SET:
if (copy_semid_from_user(&semid64, p, version))
return -EFAULT;
fallthrough;
case IPC_RMID:
return semctl_down(ns, semid, cmd, &semid64);
default:
return -EINVAL;
}
}
SYSCALL_DEFINE4(semctl, int, semid, int, semnum, int, cmd, unsigned long, arg)
{
return ksys_semctl(semid, semnum, cmd, arg, IPC_64);
}
#ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
long ksys_old_semctl(int semid, int semnum, int cmd, unsigned long arg)
{
int version = ipc_parse_version(&cmd);
return ksys_semctl(semid, semnum, cmd, arg, version);
}
SYSCALL_DEFINE4(old_semctl, int, semid, int, semnum, int, cmd, unsigned long, arg)
{
return ksys_old_semctl(semid, semnum, cmd, arg);
}
#endif
#ifdef CONFIG_COMPAT
struct compat_semid_ds {
struct compat_ipc_perm sem_perm;
old_time32_t sem_otime;
old_time32_t sem_ctime;
compat_uptr_t sem_base;
compat_uptr_t sem_pending;
compat_uptr_t sem_pending_last;
compat_uptr_t undo;
unsigned short sem_nsems;
};
static int copy_compat_semid_from_user(struct semid64_ds *out, void __user *buf,
int version)
{
memset(out, 0, sizeof(*out));
if (version == IPC_64) {
struct compat_semid64_ds __user *p = buf;
return get_compat_ipc64_perm(&out->sem_perm, &p->sem_perm);
} else {
struct compat_semid_ds __user *p = buf;
return get_compat_ipc_perm(&out->sem_perm, &p->sem_perm);
}
}
static int copy_compat_semid_to_user(void __user *buf, struct semid64_ds *in,
int version)
{
if (version == IPC_64) {
struct compat_semid64_ds v;
memset(&v, 0, sizeof(v));
to_compat_ipc64_perm(&v.sem_perm, &in->sem_perm);
v.sem_otime = lower_32_bits(in->sem_otime);
v.sem_otime_high = upper_32_bits(in->sem_otime);
v.sem_ctime = lower_32_bits(in->sem_ctime);
v.sem_ctime_high = upper_32_bits(in->sem_ctime);
v.sem_nsems = in->sem_nsems;
return copy_to_user(buf, &v, sizeof(v));
} else {
struct compat_semid_ds v;
memset(&v, 0, sizeof(v));
to_compat_ipc_perm(&v.sem_perm, &in->sem_perm);
v.sem_otime = in->sem_otime;
v.sem_ctime = in->sem_ctime;
v.sem_nsems = in->sem_nsems;
return copy_to_user(buf, &v, sizeof(v));
}
}
static long compat_ksys_semctl(int semid, int semnum, int cmd, int arg, int version)
{
void __user *p = compat_ptr(arg);
struct ipc_namespace *ns;
struct semid64_ds semid64;
int err;
ns = current->nsproxy->ipc_ns;
if (semid < 0)
return -EINVAL;
switch (cmd & (~IPC_64)) {
case IPC_INFO:
case SEM_INFO:
return semctl_info(ns, semid, cmd, p);
case IPC_STAT:
case SEM_STAT:
case SEM_STAT_ANY:
err = semctl_stat(ns, semid, cmd, &semid64);
if (err < 0)
return err;
if (copy_compat_semid_to_user(p, &semid64, version))
err = -EFAULT;
return err;
case GETVAL:
case GETPID:
case GETNCNT:
case GETZCNT:
case GETALL:
case SETALL:
return semctl_main(ns, semid, semnum, cmd, p);
case SETVAL:
return semctl_setval(ns, semid, semnum, arg);
case IPC_SET:
if (copy_compat_semid_from_user(&semid64, p, version))
return -EFAULT;
fallthrough;
case IPC_RMID:
return semctl_down(ns, semid, cmd, &semid64);
default:
return -EINVAL;
}
}
COMPAT_SYSCALL_DEFINE4(semctl, int, semid, int, semnum, int, cmd, int, arg)
{
return compat_ksys_semctl(semid, semnum, cmd, arg, IPC_64);
}
#ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION
long compat_ksys_old_semctl(int semid, int semnum, int cmd, int arg)
{
int version = compat_ipc_parse_version(&cmd);
return compat_ksys_semctl(semid, semnum, cmd, arg, version);
}
COMPAT_SYSCALL_DEFINE4(old_semctl, int, semid, int, semnum, int, cmd, int, arg)
{
return compat_ksys_old_semctl(semid, semnum, cmd, arg);
}
#endif
#endif
/* If the task doesn't already have a undo_list, then allocate one
* here. We guarantee there is only one thread using this undo list,
* and current is THE ONE
*
* If this allocation and assignment succeeds, but later
* portions of this code fail, there is no need to free the sem_undo_list.
* Just let it stay associated with the task, and it'll be freed later
* at exit time.
*
* This can block, so callers must hold no locks.
*/
static inline int get_undo_list(struct sem_undo_list **undo_listp)
{
struct sem_undo_list *undo_list;
undo_list = current->sysvsem.undo_list;
if (!undo_list) {
undo_list = kzalloc(sizeof(*undo_list), GFP_KERNEL_ACCOUNT);
if (undo_list == NULL)
return -ENOMEM;
spin_lock_init(&undo_list->lock);
refcount_set(&undo_list->refcnt, 1);
INIT_LIST_HEAD(&undo_list->list_proc);
current->sysvsem.undo_list = undo_list;
}
*undo_listp = undo_list;
return 0;
}
static struct sem_undo *__lookup_undo(struct sem_undo_list *ulp, int semid)
{
struct sem_undo *un;
list_for_each_entry_rcu(un, &ulp->list_proc, list_proc,
spin_is_locked(&ulp->lock)) {
if (un->semid == semid)
return un;
}
return NULL;
}
static struct sem_undo *lookup_undo(struct sem_undo_list *ulp, int semid)
{
struct sem_undo *un;
assert_spin_locked(&ulp->lock);
un = __lookup_undo(ulp, semid);
if (un) {
list_del_rcu(&un->list_proc);
list_add_rcu(&un->list_proc, &ulp->list_proc);
}
return un;
}
/**
* find_alloc_undo - lookup (and if not present create) undo array
* @ns: namespace
* @semid: semaphore array id
*
* The function looks up (and if not present creates) the undo structure.
* The size of the undo structure depends on the size of the semaphore
* array, thus the alloc path is not that straightforward.
* Lifetime-rules: sem_undo is rcu-protected, on success, the function
* performs a rcu_read_lock().
*/
static struct sem_undo *find_alloc_undo(struct ipc_namespace *ns, int semid)
{
struct sem_array *sma;
struct sem_undo_list *ulp;
struct sem_undo *un, *new;
int nsems, error;
error = get_undo_list(&ulp);
if (error)
return ERR_PTR(error);
rcu_read_lock();
spin_lock(&ulp->lock);
un = lookup_undo(ulp, semid);
spin_unlock(&ulp->lock);
if (likely(un != NULL))
goto out;
/* no undo structure around - allocate one. */
/* step 1: figure out the size of the semaphore array */
sma = sem_obtain_object_check(ns, semid);
if (IS_ERR(sma)) {
rcu_read_unlock();
return ERR_CAST(sma);
}
nsems = sma->sem_nsems;
if (!ipc_rcu_getref(&sma->sem_perm)) {
rcu_read_unlock();
un = ERR_PTR(-EIDRM);
goto out;
}
rcu_read_unlock();
/* step 2: allocate new undo structure */
new = kvzalloc(struct_size(new, semadj, nsems), GFP_KERNEL_ACCOUNT);
if (!new) {
ipc_rcu_putref(&sma->sem_perm, sem_rcu_free);
return ERR_PTR(-ENOMEM);
}
/* step 3: Acquire the lock on semaphore array */
rcu_read_lock();
sem_lock_and_putref(sma);
if (!ipc_valid_object(&sma->sem_perm)) {
sem_unlock(sma, -1);
rcu_read_unlock();
kvfree(new);
un = ERR_PTR(-EIDRM);
goto out;
}
spin_lock(&ulp->lock);
/*
* step 4: check for races: did someone else allocate the undo struct?
*/
un = lookup_undo(ulp, semid);
if (un) {
spin_unlock(&ulp->lock);
kvfree(new);
goto success;
}
/* step 5: initialize & link new undo structure */
new->ulp = ulp;
new->semid = semid;
assert_spin_locked(&ulp->lock);
list_add_rcu(&new->list_proc, &ulp->list_proc);
ipc_assert_locked_object(&sma->sem_perm);
list_add(&new->list_id, &sma->list_id);
un = new;
spin_unlock(&ulp->lock);
success:
sem_unlock(sma, -1);
out:
return un;
}
long __do_semtimedop(int semid, struct sembuf *sops,
unsigned nsops, const struct timespec64 *timeout,
struct ipc_namespace *ns)
{
int error = -EINVAL;
struct sem_array *sma;
struct sembuf *sop;
struct sem_undo *un;
int max, locknum;
bool undos = false, alter = false, dupsop = false;
struct sem_queue queue;
unsigned long dup = 0;
ktime_t expires, *exp = NULL;
bool timed_out = false;
if (nsops < 1 || semid < 0)
return -EINVAL;
if (nsops > ns->sc_semopm)
return -E2BIG;
if (timeout) {
if (!timespec64_valid(timeout))
return -EINVAL;
expires = ktime_add_safe(ktime_get(),
timespec64_to_ktime(*timeout));
exp = &expires;
}
max = 0;
for (sop = sops; sop < sops + nsops; sop++) {
unsigned long mask = 1ULL << ((sop->sem_num) % BITS_PER_LONG);
if (sop->sem_num >= max)
max = sop->sem_num;
if (sop->sem_flg & SEM_UNDO)
undos = true;
if (dup & mask) {
/*
* There was a previous alter access that appears
* to have accessed the same semaphore, thus use
* the dupsop logic. "appears", because the detection
* can only check % BITS_PER_LONG.
*/
dupsop = true;
}
if (sop->sem_op != 0) {
alter = true;
dup |= mask;
}
}
if (undos) {
/* On success, find_alloc_undo takes the rcu_read_lock */
un = find_alloc_undo(ns, semid);
if (IS_ERR(un)) {
error = PTR_ERR(un);
goto out;
}
} else {
un = NULL;
rcu_read_lock();
}
sma = sem_obtain_object_check(ns, semid);
if (IS_ERR(sma)) {
rcu_read_unlock();
error = PTR_ERR(sma);
goto out;
}
error = -EFBIG;
if (max >= sma->sem_nsems) {
rcu_read_unlock();
goto out;
}
error = -EACCES;
if (ipcperms(ns, &sma->sem_perm, alter ? S_IWUGO : S_IRUGO)) {
rcu_read_unlock();
goto out;
}
error = security_sem_semop(&sma->sem_perm, sops, nsops, alter);
if (error) {
rcu_read_unlock();
goto out;
}
error = -EIDRM;
locknum = sem_lock(sma, sops, nsops);
/*
* We eventually might perform the following check in a lockless
* fashion, considering ipc_valid_object() locking constraints.
* If nsops == 1 and there is no contention for sem_perm.lock, then
* only a per-semaphore lock is held and it's OK to proceed with the
* check below. More details on the fine grained locking scheme
* entangled here and why it's RMID race safe on comments at sem_lock()
*/
if (!ipc_valid_object(&sma->sem_perm))
goto out_unlock;
/*
* semid identifiers are not unique - find_alloc_undo may have
* allocated an undo structure, it was invalidated by an RMID
* and now a new array with received the same id. Check and fail.
* This case can be detected checking un->semid. The existence of
* "un" itself is guaranteed by rcu.
*/
if (un && un->semid == -1)
goto out_unlock;
queue.sops = sops;
queue.nsops = nsops;
queue.undo = un;
queue.pid = task_tgid(current);
queue.alter = alter;
queue.dupsop = dupsop;
error = perform_atomic_semop(sma, &queue);
if (error == 0) { /* non-blocking successful path */
DEFINE_WAKE_Q(wake_q);
/*
* If the operation was successful, then do
* the required updates.
*/
if (alter)
do_smart_update(sma, sops, nsops, 1, &wake_q);
else
set_semotime(sma, sops);
sem_unlock(sma, locknum);
rcu_read_unlock();
wake_up_q(&wake_q);
goto out;
}
if (error < 0) /* non-blocking error path */
goto out_unlock;
/*
* We need to sleep on this operation, so we put the current
* task into the pending queue and go to sleep.
*/
if (nsops == 1) {
struct sem *curr;
int idx = array_index_nospec(sops->sem_num, sma->sem_nsems);
curr = &sma->sems[idx];
if (alter) {
if (sma->complex_count) {
list_add_tail(&queue.list,
&sma->pending_alter);
} else {
list_add_tail(&queue.list,
&curr->pending_alter);
}
} else {
list_add_tail(&queue.list, &curr->pending_const);
}
} else {
if (!sma->complex_count)
merge_queues(sma);
if (alter)
list_add_tail(&queue.list, &sma->pending_alter);
else
list_add_tail(&queue.list, &sma->pending_const);
sma->complex_count++;
}
do {
/* memory ordering ensured by the lock in sem_lock() */
WRITE_ONCE(queue.status, -EINTR);
queue.sleeper = current;
/* memory ordering is ensured by the lock in sem_lock() */
__set_current_state(TASK_INTERRUPTIBLE);
sem_unlock(sma, locknum);
rcu_read_unlock();
timed_out = !schedule_hrtimeout_range(exp,
current->timer_slack_ns, HRTIMER_MODE_ABS);
/*
* fastpath: the semop has completed, either successfully or
* not, from the syscall pov, is quite irrelevant to us at this
* point; we're done.
*
* We _do_ care, nonetheless, about being awoken by a signal or
* spuriously. The queue.status is checked again in the
* slowpath (aka after taking sem_lock), such that we can detect
* scenarios where we were awakened externally, during the
* window between wake_q_add() and wake_up_q().
*/
rcu_read_lock();
error = READ_ONCE(queue.status);
if (error != -EINTR) {
/* see SEM_BARRIER_2 for purpose/pairing */
smp_acquire__after_ctrl_dep();
rcu_read_unlock();
goto out;
}
locknum = sem_lock(sma, sops, nsops);
if (!ipc_valid_object(&sma->sem_perm))
goto out_unlock;
/*
* No necessity for any barrier: We are protect by sem_lock()
*/
error = READ_ONCE(queue.status);
/*
* If queue.status != -EINTR we are woken up by another process.
* Leave without unlink_queue(), but with sem_unlock().
*/
if (error != -EINTR)
goto out_unlock;
/*
* If an interrupt occurred we have to clean up the queue.
*/
if (timed_out)
error = -EAGAIN;
} while (error == -EINTR && !signal_pending(current)); /* spurious */
unlink_queue(sma, &queue);
out_unlock:
sem_unlock(sma, locknum);
rcu_read_unlock();
out:
return error;
}
static long do_semtimedop(int semid, struct sembuf __user *tsops,
unsigned nsops, const struct timespec64 *timeout)
{
struct sembuf fast_sops[SEMOPM_FAST];
struct sembuf *sops = fast_sops;
struct ipc_namespace *ns;
int ret;
ns = current->nsproxy->ipc_ns;
if (nsops > ns->sc_semopm)
return -E2BIG;
if (nsops < 1)
return -EINVAL;
if (nsops > SEMOPM_FAST) {
sops = kvmalloc_array(nsops, sizeof(*sops), GFP_KERNEL);
if (sops == NULL)
return -ENOMEM;
}
if (copy_from_user(sops, tsops, nsops * sizeof(*tsops))) {
ret = -EFAULT;
goto out_free;
}
ret = __do_semtimedop(semid, sops, nsops, timeout, ns);
out_free:
if (sops != fast_sops)
kvfree(sops);
return ret;
}
long ksys_semtimedop(int semid, struct sembuf __user *tsops,
unsigned int nsops, const struct __kernel_timespec __user *timeout)
{
if (timeout) {
struct timespec64 ts;
if (get_timespec64(&ts, timeout))
return -EFAULT;
return do_semtimedop(semid, tsops, nsops, &ts);
}
return do_semtimedop(semid, tsops, nsops, NULL);
}
SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops,
unsigned int, nsops, const struct __kernel_timespec __user *, timeout)
{
return ksys_semtimedop(semid, tsops, nsops, timeout);
}
#ifdef CONFIG_COMPAT_32BIT_TIME
long compat_ksys_semtimedop(int semid, struct sembuf __user *tsems,
unsigned int nsops,
const struct old_timespec32 __user *timeout)
{
if (timeout) {
struct timespec64 ts;
if (get_old_timespec32(&ts, timeout))
return -EFAULT;
return do_semtimedop(semid, tsems, nsops, &ts);
}
return do_semtimedop(semid, tsems, nsops, NULL);
}
SYSCALL_DEFINE4(semtimedop_time32, int, semid, struct sembuf __user *, tsems,
unsigned int, nsops,
const struct old_timespec32 __user *, timeout)
{
return compat_ksys_semtimedop(semid, tsems, nsops, timeout);
}
#endif
SYSCALL_DEFINE3(semop, int, semid, struct sembuf __user *, tsops,
unsigned, nsops)
{
return do_semtimedop(semid, tsops, nsops, NULL);
}
/* If CLONE_SYSVSEM is set, establish sharing of SEM_UNDO state between
* parent and child tasks.
*/
int copy_semundo(unsigned long clone_flags, struct task_struct *tsk)
{
struct sem_undo_list *undo_list;
int error;
if (clone_flags & CLONE_SYSVSEM) {
error = get_undo_list(&undo_list);
if (error)
return error;
refcount_inc(&undo_list->refcnt);
tsk->sysvsem.undo_list = undo_list;
} else
tsk->sysvsem.undo_list = NULL;
return 0;
}
/*
* add semadj values to semaphores, free undo structures.
* undo structures are not freed when semaphore arrays are destroyed
* so some of them may be out of date.
* IMPLEMENTATION NOTE: There is some confusion over whether the
* set of adjustments that needs to be done should be done in an atomic
* manner or not. That is, if we are attempting to decrement the semval
* should we queue up and wait until we can do so legally?
* The original implementation attempted to do this (queue and wait).
* The current implementation does not do so. The POSIX standard
* and SVID should be consulted to determine what behavior is mandated.
*/
void exit_sem(struct task_struct *tsk)
{
struct sem_undo_list *ulp;
ulp = tsk->sysvsem.undo_list;
if (!ulp)
return;
tsk->sysvsem.undo_list = NULL;
if (!refcount_dec_and_test(&ulp->refcnt))
return;
for (;;) {
struct sem_array *sma;
struct sem_undo *un;
int semid, i;
DEFINE_WAKE_Q(wake_q);
cond_resched();
rcu_read_lock();
un = list_entry_rcu(ulp->list_proc.next,
struct sem_undo, list_proc);
if (&un->list_proc == &ulp->list_proc) {
/*
* We must wait for freeary() before freeing this ulp,
* in case we raced with last sem_undo. There is a small
* possibility where we exit while freeary() didn't
* finish unlocking sem_undo_list.
*/
spin_lock(&ulp->lock);
spin_unlock(&ulp->lock);
rcu_read_unlock();
break;
}
spin_lock(&ulp->lock);
semid = un->semid;
spin_unlock(&ulp->lock);
/* exit_sem raced with IPC_RMID, nothing to do */
if (semid == -1) {
rcu_read_unlock();
continue;
}
sma = sem_obtain_object_check(tsk->nsproxy->ipc_ns, semid);
/* exit_sem raced with IPC_RMID, nothing to do */
if (IS_ERR(sma)) {
rcu_read_unlock();
continue;
}
sem_lock(sma, NULL, -1);
/* exit_sem raced with IPC_RMID, nothing to do */
if (!ipc_valid_object(&sma->sem_perm)) {
sem_unlock(sma, -1);
rcu_read_unlock();
continue;
}
un = __lookup_undo(ulp, semid);
if (un == NULL) {
/* exit_sem raced with IPC_RMID+semget() that created
* exactly the same semid. Nothing to do.
*/
sem_unlock(sma, -1);
rcu_read_unlock();
continue;
}
/* remove un from the linked lists */
ipc_assert_locked_object(&sma->sem_perm);
list_del(&un->list_id);
spin_lock(&ulp->lock);
list_del_rcu(&un->list_proc);
spin_unlock(&ulp->lock);
/* perform adjustments registered in un */
for (i = 0; i < sma->sem_nsems; i++) {
struct sem *semaphore = &sma->sems[i];
if (un->semadj[i]) {
semaphore->semval += un->semadj[i];
/*
* Range checks of the new semaphore value,
* not defined by sus:
* - Some unices ignore the undo entirely
* (e.g. HP UX 11i 11.22, Tru64 V5.1)
* - some cap the value (e.g. FreeBSD caps
* at 0, but doesn't enforce SEMVMX)
*
* Linux caps the semaphore value, both at 0
* and at SEMVMX.
*
* Manfred <[email protected]>
*/
if (semaphore->semval < 0)
semaphore->semval = 0;
if (semaphore->semval > SEMVMX)
semaphore->semval = SEMVMX;
ipc_update_pid(&semaphore->sempid, task_tgid(current));
}
}
/* maybe some queued-up processes were waiting for this */
do_smart_update(sma, NULL, 0, 1, &wake_q);
sem_unlock(sma, -1);
rcu_read_unlock();
wake_up_q(&wake_q);
kvfree_rcu(un, rcu);
}
kfree(ulp);
}
#ifdef CONFIG_PROC_FS
static int sysvipc_sem_proc_show(struct seq_file *s, void *it)
{
struct user_namespace *user_ns = seq_user_ns(s);
struct kern_ipc_perm *ipcp = it;
struct sem_array *sma = container_of(ipcp, struct sem_array, sem_perm);
time64_t sem_otime;
/*
* The proc interface isn't aware of sem_lock(), it calls
* ipc_lock_object(), i.e. spin_lock(&sma->sem_perm.lock).
* (in sysvipc_find_ipc)
* In order to stay compatible with sem_lock(), we must
* enter / leave complex_mode.
*/
complexmode_enter(sma);
sem_otime = get_semotime(sma);
seq_printf(s,
"%10d %10d %4o %10u %5u %5u %5u %5u %10llu %10llu\n",
sma->sem_perm.key,
sma->sem_perm.id,
sma->sem_perm.mode,
sma->sem_nsems,
from_kuid_munged(user_ns, sma->sem_perm.uid),
from_kgid_munged(user_ns, sma->sem_perm.gid),
from_kuid_munged(user_ns, sma->sem_perm.cuid),
from_kgid_munged(user_ns, sma->sem_perm.cgid),
sem_otime,
sma->sem_ctime);
complexmode_tryleave(sma);
return 0;
}
#endif
| linux-master | ipc/sem.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2007 IBM Corporation
*
* Author: Cedric Le Goater <[email protected]>
*/
#include <linux/nsproxy.h>
#include <linux/ipc_namespace.h>
#include <linux/sysctl.h>
#include <linux/stat.h>
#include <linux/capability.h>
#include <linux/slab.h>
static int msg_max_limit_min = MIN_MSGMAX;
static int msg_max_limit_max = HARD_MSGMAX;
static int msg_maxsize_limit_min = MIN_MSGSIZEMAX;
static int msg_maxsize_limit_max = HARD_MSGSIZEMAX;
static struct ctl_table mq_sysctls[] = {
{
.procname = "queues_max",
.data = &init_ipc_ns.mq_queues_max,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{
.procname = "msg_max",
.data = &init_ipc_ns.mq_msg_max,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &msg_max_limit_min,
.extra2 = &msg_max_limit_max,
},
{
.procname = "msgsize_max",
.data = &init_ipc_ns.mq_msgsize_max,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &msg_maxsize_limit_min,
.extra2 = &msg_maxsize_limit_max,
},
{
.procname = "msg_default",
.data = &init_ipc_ns.mq_msg_default,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &msg_max_limit_min,
.extra2 = &msg_max_limit_max,
},
{
.procname = "msgsize_default",
.data = &init_ipc_ns.mq_msgsize_default,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &msg_maxsize_limit_min,
.extra2 = &msg_maxsize_limit_max,
},
{}
};
static struct ctl_table_set *set_lookup(struct ctl_table_root *root)
{
return ¤t->nsproxy->ipc_ns->mq_set;
}
static int set_is_seen(struct ctl_table_set *set)
{
return ¤t->nsproxy->ipc_ns->mq_set == set;
}
static struct ctl_table_root set_root = {
.lookup = set_lookup,
};
bool setup_mq_sysctls(struct ipc_namespace *ns)
{
struct ctl_table *tbl;
setup_sysctl_set(&ns->mq_set, &set_root, set_is_seen);
tbl = kmemdup(mq_sysctls, sizeof(mq_sysctls), GFP_KERNEL);
if (tbl) {
int i;
for (i = 0; i < ARRAY_SIZE(mq_sysctls); i++) {
if (tbl[i].data == &init_ipc_ns.mq_queues_max)
tbl[i].data = &ns->mq_queues_max;
else if (tbl[i].data == &init_ipc_ns.mq_msg_max)
tbl[i].data = &ns->mq_msg_max;
else if (tbl[i].data == &init_ipc_ns.mq_msgsize_max)
tbl[i].data = &ns->mq_msgsize_max;
else if (tbl[i].data == &init_ipc_ns.mq_msg_default)
tbl[i].data = &ns->mq_msg_default;
else if (tbl[i].data == &init_ipc_ns.mq_msgsize_default)
tbl[i].data = &ns->mq_msgsize_default;
else
tbl[i].data = NULL;
}
ns->mq_sysctls = __register_sysctl_table(&ns->mq_set,
"fs/mqueue", tbl,
ARRAY_SIZE(mq_sysctls));
}
if (!ns->mq_sysctls) {
kfree(tbl);
retire_sysctl_set(&ns->mq_set);
return false;
}
return true;
}
void retire_mq_sysctls(struct ipc_namespace *ns)
{
struct ctl_table *tbl;
tbl = ns->mq_sysctls->ctl_table_arg;
unregister_sysctl_table(ns->mq_sysctls);
retire_sysctl_set(&ns->mq_set);
kfree(tbl);
}
| linux-master | ipc/mq_sysctl.c |
/*
* POSIX message queues filesystem for Linux.
*
* Copyright (C) 2003,2004 Krzysztof Benedyczak ([email protected])
* Michal Wronski ([email protected])
*
* Spinlocks: Mohamed Abbas ([email protected])
* Lockless receive & send, fd based notify:
* Manfred Spraul ([email protected])
*
* Audit: George Wilson ([email protected])
*
* This file is released under the GPL.
*/
#include <linux/capability.h>
#include <linux/init.h>
#include <linux/pagemap.h>
#include <linux/file.h>
#include <linux/mount.h>
#include <linux/fs_context.h>
#include <linux/namei.h>
#include <linux/sysctl.h>
#include <linux/poll.h>
#include <linux/mqueue.h>
#include <linux/msg.h>
#include <linux/skbuff.h>
#include <linux/vmalloc.h>
#include <linux/netlink.h>
#include <linux/syscalls.h>
#include <linux/audit.h>
#include <linux/signal.h>
#include <linux/mutex.h>
#include <linux/nsproxy.h>
#include <linux/pid.h>
#include <linux/ipc_namespace.h>
#include <linux/user_namespace.h>
#include <linux/slab.h>
#include <linux/sched/wake_q.h>
#include <linux/sched/signal.h>
#include <linux/sched/user.h>
#include <net/sock.h>
#include "util.h"
struct mqueue_fs_context {
struct ipc_namespace *ipc_ns;
bool newns; /* Set if newly created ipc namespace */
};
#define MQUEUE_MAGIC 0x19800202
#define DIRENT_SIZE 20
#define FILENT_SIZE 80
#define SEND 0
#define RECV 1
#define STATE_NONE 0
#define STATE_READY 1
struct posix_msg_tree_node {
struct rb_node rb_node;
struct list_head msg_list;
int priority;
};
/*
* Locking:
*
* Accesses to a message queue are synchronized by acquiring info->lock.
*
* There are two notable exceptions:
* - The actual wakeup of a sleeping task is performed using the wake_q
* framework. info->lock is already released when wake_up_q is called.
* - The exit codepaths after sleeping check ext_wait_queue->state without
* any locks. If it is STATE_READY, then the syscall is completed without
* acquiring info->lock.
*
* MQ_BARRIER:
* To achieve proper release/acquire memory barrier pairing, the state is set to
* STATE_READY with smp_store_release(), and it is read with READ_ONCE followed
* by smp_acquire__after_ctrl_dep(). In addition, wake_q_add_safe() is used.
*
* This prevents the following races:
*
* 1) With the simple wake_q_add(), the task could be gone already before
* the increase of the reference happens
* Thread A
* Thread B
* WRITE_ONCE(wait.state, STATE_NONE);
* schedule_hrtimeout()
* wake_q_add(A)
* if (cmpxchg()) // success
* ->state = STATE_READY (reordered)
* <timeout returns>
* if (wait.state == STATE_READY) return;
* sysret to user space
* sys_exit()
* get_task_struct() // UaF
*
* Solution: Use wake_q_add_safe() and perform the get_task_struct() before
* the smp_store_release() that does ->state = STATE_READY.
*
* 2) Without proper _release/_acquire barriers, the woken up task
* could read stale data
*
* Thread A
* Thread B
* do_mq_timedreceive
* WRITE_ONCE(wait.state, STATE_NONE);
* schedule_hrtimeout()
* state = STATE_READY;
* <timeout returns>
* if (wait.state == STATE_READY) return;
* msg_ptr = wait.msg; // Access to stale data!
* receiver->msg = message; (reordered)
*
* Solution: use _release and _acquire barriers.
*
* 3) There is intentionally no barrier when setting current->state
* to TASK_INTERRUPTIBLE: spin_unlock(&info->lock) provides the
* release memory barrier, and the wakeup is triggered when holding
* info->lock, i.e. spin_lock(&info->lock) provided a pairing
* acquire memory barrier.
*/
struct ext_wait_queue { /* queue of sleeping tasks */
struct task_struct *task;
struct list_head list;
struct msg_msg *msg; /* ptr of loaded message */
int state; /* one of STATE_* values */
};
struct mqueue_inode_info {
spinlock_t lock;
struct inode vfs_inode;
wait_queue_head_t wait_q;
struct rb_root msg_tree;
struct rb_node *msg_tree_rightmost;
struct posix_msg_tree_node *node_cache;
struct mq_attr attr;
struct sigevent notify;
struct pid *notify_owner;
u32 notify_self_exec_id;
struct user_namespace *notify_user_ns;
struct ucounts *ucounts; /* user who created, for accounting */
struct sock *notify_sock;
struct sk_buff *notify_cookie;
/* for tasks waiting for free space and messages, respectively */
struct ext_wait_queue e_wait_q[2];
unsigned long qsize; /* size of queue in memory (sum of all msgs) */
};
static struct file_system_type mqueue_fs_type;
static const struct inode_operations mqueue_dir_inode_operations;
static const struct file_operations mqueue_file_operations;
static const struct super_operations mqueue_super_ops;
static const struct fs_context_operations mqueue_fs_context_ops;
static void remove_notification(struct mqueue_inode_info *info);
static struct kmem_cache *mqueue_inode_cachep;
static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
{
return container_of(inode, struct mqueue_inode_info, vfs_inode);
}
/*
* This routine should be called with the mq_lock held.
*/
static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode)
{
return get_ipc_ns(inode->i_sb->s_fs_info);
}
static struct ipc_namespace *get_ns_from_inode(struct inode *inode)
{
struct ipc_namespace *ns;
spin_lock(&mq_lock);
ns = __get_ns_from_inode(inode);
spin_unlock(&mq_lock);
return ns;
}
/* Auxiliary functions to manipulate messages' list */
static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info)
{
struct rb_node **p, *parent = NULL;
struct posix_msg_tree_node *leaf;
bool rightmost = true;
p = &info->msg_tree.rb_node;
while (*p) {
parent = *p;
leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
if (likely(leaf->priority == msg->m_type))
goto insert_msg;
else if (msg->m_type < leaf->priority) {
p = &(*p)->rb_left;
rightmost = false;
} else
p = &(*p)->rb_right;
}
if (info->node_cache) {
leaf = info->node_cache;
info->node_cache = NULL;
} else {
leaf = kmalloc(sizeof(*leaf), GFP_ATOMIC);
if (!leaf)
return -ENOMEM;
INIT_LIST_HEAD(&leaf->msg_list);
}
leaf->priority = msg->m_type;
if (rightmost)
info->msg_tree_rightmost = &leaf->rb_node;
rb_link_node(&leaf->rb_node, parent, p);
rb_insert_color(&leaf->rb_node, &info->msg_tree);
insert_msg:
info->attr.mq_curmsgs++;
info->qsize += msg->m_ts;
list_add_tail(&msg->m_list, &leaf->msg_list);
return 0;
}
static inline void msg_tree_erase(struct posix_msg_tree_node *leaf,
struct mqueue_inode_info *info)
{
struct rb_node *node = &leaf->rb_node;
if (info->msg_tree_rightmost == node)
info->msg_tree_rightmost = rb_prev(node);
rb_erase(node, &info->msg_tree);
if (info->node_cache)
kfree(leaf);
else
info->node_cache = leaf;
}
static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
{
struct rb_node *parent = NULL;
struct posix_msg_tree_node *leaf;
struct msg_msg *msg;
try_again:
/*
* During insert, low priorities go to the left and high to the
* right. On receive, we want the highest priorities first, so
* walk all the way to the right.
*/
parent = info->msg_tree_rightmost;
if (!parent) {
if (info->attr.mq_curmsgs) {
pr_warn_once("Inconsistency in POSIX message queue, "
"no tree element, but supposedly messages "
"should exist!\n");
info->attr.mq_curmsgs = 0;
}
return NULL;
}
leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
if (unlikely(list_empty(&leaf->msg_list))) {
pr_warn_once("Inconsistency in POSIX message queue, "
"empty leaf node but we haven't implemented "
"lazy leaf delete!\n");
msg_tree_erase(leaf, info);
goto try_again;
} else {
msg = list_first_entry(&leaf->msg_list,
struct msg_msg, m_list);
list_del(&msg->m_list);
if (list_empty(&leaf->msg_list)) {
msg_tree_erase(leaf, info);
}
}
info->attr.mq_curmsgs--;
info->qsize -= msg->m_ts;
return msg;
}
static struct inode *mqueue_get_inode(struct super_block *sb,
struct ipc_namespace *ipc_ns, umode_t mode,
struct mq_attr *attr)
{
struct inode *inode;
int ret = -ENOMEM;
inode = new_inode(sb);
if (!inode)
goto err;
inode->i_ino = get_next_ino();
inode->i_mode = mode;
inode->i_uid = current_fsuid();
inode->i_gid = current_fsgid();
inode->i_mtime = inode->i_atime = inode_set_ctime_current(inode);
if (S_ISREG(mode)) {
struct mqueue_inode_info *info;
unsigned long mq_bytes, mq_treesize;
inode->i_fop = &mqueue_file_operations;
inode->i_size = FILENT_SIZE;
/* mqueue specific info */
info = MQUEUE_I(inode);
spin_lock_init(&info->lock);
init_waitqueue_head(&info->wait_q);
INIT_LIST_HEAD(&info->e_wait_q[0].list);
INIT_LIST_HEAD(&info->e_wait_q[1].list);
info->notify_owner = NULL;
info->notify_user_ns = NULL;
info->qsize = 0;
info->ucounts = NULL; /* set when all is ok */
info->msg_tree = RB_ROOT;
info->msg_tree_rightmost = NULL;
info->node_cache = NULL;
memset(&info->attr, 0, sizeof(info->attr));
info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
ipc_ns->mq_msg_default);
info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
ipc_ns->mq_msgsize_default);
if (attr) {
info->attr.mq_maxmsg = attr->mq_maxmsg;
info->attr.mq_msgsize = attr->mq_msgsize;
}
/*
* We used to allocate a static array of pointers and account
* the size of that array as well as one msg_msg struct per
* possible message into the queue size. That's no longer
* accurate as the queue is now an rbtree and will grow and
* shrink depending on usage patterns. We can, however, still
* account one msg_msg struct per message, but the nodes are
* allocated depending on priority usage, and most programs
* only use one, or a handful, of priorities. However, since
* this is pinned memory, we need to assume worst case, so
* that means the min(mq_maxmsg, max_priorities) * struct
* posix_msg_tree_node.
*/
ret = -EINVAL;
if (info->attr.mq_maxmsg <= 0 || info->attr.mq_msgsize <= 0)
goto out_inode;
if (capable(CAP_SYS_RESOURCE)) {
if (info->attr.mq_maxmsg > HARD_MSGMAX ||
info->attr.mq_msgsize > HARD_MSGSIZEMAX)
goto out_inode;
} else {
if (info->attr.mq_maxmsg > ipc_ns->mq_msg_max ||
info->attr.mq_msgsize > ipc_ns->mq_msgsize_max)
goto out_inode;
}
ret = -EOVERFLOW;
/* check for overflow */
if (info->attr.mq_msgsize > ULONG_MAX/info->attr.mq_maxmsg)
goto out_inode;
mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
sizeof(struct posix_msg_tree_node);
mq_bytes = info->attr.mq_maxmsg * info->attr.mq_msgsize;
if (mq_bytes + mq_treesize < mq_bytes)
goto out_inode;
mq_bytes += mq_treesize;
info->ucounts = get_ucounts(current_ucounts());
if (info->ucounts) {
long msgqueue;
spin_lock(&mq_lock);
msgqueue = inc_rlimit_ucounts(info->ucounts, UCOUNT_RLIMIT_MSGQUEUE, mq_bytes);
if (msgqueue == LONG_MAX || msgqueue > rlimit(RLIMIT_MSGQUEUE)) {
dec_rlimit_ucounts(info->ucounts, UCOUNT_RLIMIT_MSGQUEUE, mq_bytes);
spin_unlock(&mq_lock);
put_ucounts(info->ucounts);
info->ucounts = NULL;
/* mqueue_evict_inode() releases info->messages */
ret = -EMFILE;
goto out_inode;
}
spin_unlock(&mq_lock);
}
} else if (S_ISDIR(mode)) {
inc_nlink(inode);
/* Some things misbehave if size == 0 on a directory */
inode->i_size = 2 * DIRENT_SIZE;
inode->i_op = &mqueue_dir_inode_operations;
inode->i_fop = &simple_dir_operations;
}
return inode;
out_inode:
iput(inode);
err:
return ERR_PTR(ret);
}
static int mqueue_fill_super(struct super_block *sb, struct fs_context *fc)
{
struct inode *inode;
struct ipc_namespace *ns = sb->s_fs_info;
sb->s_iflags |= SB_I_NOEXEC | SB_I_NODEV;
sb->s_blocksize = PAGE_SIZE;
sb->s_blocksize_bits = PAGE_SHIFT;
sb->s_magic = MQUEUE_MAGIC;
sb->s_op = &mqueue_super_ops;
inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
if (IS_ERR(inode))
return PTR_ERR(inode);
sb->s_root = d_make_root(inode);
if (!sb->s_root)
return -ENOMEM;
return 0;
}
static int mqueue_get_tree(struct fs_context *fc)
{
struct mqueue_fs_context *ctx = fc->fs_private;
/*
* With a newly created ipc namespace, we don't need to do a search
* for an ipc namespace match, but we still need to set s_fs_info.
*/
if (ctx->newns) {
fc->s_fs_info = ctx->ipc_ns;
return get_tree_nodev(fc, mqueue_fill_super);
}
return get_tree_keyed(fc, mqueue_fill_super, ctx->ipc_ns);
}
static void mqueue_fs_context_free(struct fs_context *fc)
{
struct mqueue_fs_context *ctx = fc->fs_private;
put_ipc_ns(ctx->ipc_ns);
kfree(ctx);
}
static int mqueue_init_fs_context(struct fs_context *fc)
{
struct mqueue_fs_context *ctx;
ctx = kzalloc(sizeof(struct mqueue_fs_context), GFP_KERNEL);
if (!ctx)
return -ENOMEM;
ctx->ipc_ns = get_ipc_ns(current->nsproxy->ipc_ns);
put_user_ns(fc->user_ns);
fc->user_ns = get_user_ns(ctx->ipc_ns->user_ns);
fc->fs_private = ctx;
fc->ops = &mqueue_fs_context_ops;
return 0;
}
/*
* mq_init_ns() is currently the only caller of mq_create_mount().
* So the ns parameter is always a newly created ipc namespace.
*/
static struct vfsmount *mq_create_mount(struct ipc_namespace *ns)
{
struct mqueue_fs_context *ctx;
struct fs_context *fc;
struct vfsmount *mnt;
fc = fs_context_for_mount(&mqueue_fs_type, SB_KERNMOUNT);
if (IS_ERR(fc))
return ERR_CAST(fc);
ctx = fc->fs_private;
ctx->newns = true;
put_ipc_ns(ctx->ipc_ns);
ctx->ipc_ns = get_ipc_ns(ns);
put_user_ns(fc->user_ns);
fc->user_ns = get_user_ns(ctx->ipc_ns->user_ns);
mnt = fc_mount(fc);
put_fs_context(fc);
return mnt;
}
static void init_once(void *foo)
{
struct mqueue_inode_info *p = foo;
inode_init_once(&p->vfs_inode);
}
static struct inode *mqueue_alloc_inode(struct super_block *sb)
{
struct mqueue_inode_info *ei;
ei = alloc_inode_sb(sb, mqueue_inode_cachep, GFP_KERNEL);
if (!ei)
return NULL;
return &ei->vfs_inode;
}
static void mqueue_free_inode(struct inode *inode)
{
kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
}
static void mqueue_evict_inode(struct inode *inode)
{
struct mqueue_inode_info *info;
struct ipc_namespace *ipc_ns;
struct msg_msg *msg, *nmsg;
LIST_HEAD(tmp_msg);
clear_inode(inode);
if (S_ISDIR(inode->i_mode))
return;
ipc_ns = get_ns_from_inode(inode);
info = MQUEUE_I(inode);
spin_lock(&info->lock);
while ((msg = msg_get(info)) != NULL)
list_add_tail(&msg->m_list, &tmp_msg);
kfree(info->node_cache);
spin_unlock(&info->lock);
list_for_each_entry_safe(msg, nmsg, &tmp_msg, m_list) {
list_del(&msg->m_list);
free_msg(msg);
}
if (info->ucounts) {
unsigned long mq_bytes, mq_treesize;
/* Total amount of bytes accounted for the mqueue */
mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
sizeof(struct posix_msg_tree_node);
mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
info->attr.mq_msgsize);
spin_lock(&mq_lock);
dec_rlimit_ucounts(info->ucounts, UCOUNT_RLIMIT_MSGQUEUE, mq_bytes);
/*
* get_ns_from_inode() ensures that the
* (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
* to which we now hold a reference, or it is NULL.
* We can't put it here under mq_lock, though.
*/
if (ipc_ns)
ipc_ns->mq_queues_count--;
spin_unlock(&mq_lock);
put_ucounts(info->ucounts);
info->ucounts = NULL;
}
if (ipc_ns)
put_ipc_ns(ipc_ns);
}
static int mqueue_create_attr(struct dentry *dentry, umode_t mode, void *arg)
{
struct inode *dir = dentry->d_parent->d_inode;
struct inode *inode;
struct mq_attr *attr = arg;
int error;
struct ipc_namespace *ipc_ns;
spin_lock(&mq_lock);
ipc_ns = __get_ns_from_inode(dir);
if (!ipc_ns) {
error = -EACCES;
goto out_unlock;
}
if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
!capable(CAP_SYS_RESOURCE)) {
error = -ENOSPC;
goto out_unlock;
}
ipc_ns->mq_queues_count++;
spin_unlock(&mq_lock);
inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
if (IS_ERR(inode)) {
error = PTR_ERR(inode);
spin_lock(&mq_lock);
ipc_ns->mq_queues_count--;
goto out_unlock;
}
put_ipc_ns(ipc_ns);
dir->i_size += DIRENT_SIZE;
dir->i_mtime = dir->i_atime = inode_set_ctime_current(dir);
d_instantiate(dentry, inode);
dget(dentry);
return 0;
out_unlock:
spin_unlock(&mq_lock);
if (ipc_ns)
put_ipc_ns(ipc_ns);
return error;
}
static int mqueue_create(struct mnt_idmap *idmap, struct inode *dir,
struct dentry *dentry, umode_t mode, bool excl)
{
return mqueue_create_attr(dentry, mode, NULL);
}
static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
{
struct inode *inode = d_inode(dentry);
dir->i_mtime = dir->i_atime = inode_set_ctime_current(dir);
dir->i_size -= DIRENT_SIZE;
drop_nlink(inode);
dput(dentry);
return 0;
}
/*
* This is routine for system read from queue file.
* To avoid mess with doing here some sort of mq_receive we allow
* to read only queue size & notification info (the only values
* that are interesting from user point of view and aren't accessible
* through std routines)
*/
static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
size_t count, loff_t *off)
{
struct inode *inode = file_inode(filp);
struct mqueue_inode_info *info = MQUEUE_I(inode);
char buffer[FILENT_SIZE];
ssize_t ret;
spin_lock(&info->lock);
snprintf(buffer, sizeof(buffer),
"QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
info->qsize,
info->notify_owner ? info->notify.sigev_notify : 0,
(info->notify_owner &&
info->notify.sigev_notify == SIGEV_SIGNAL) ?
info->notify.sigev_signo : 0,
pid_vnr(info->notify_owner));
spin_unlock(&info->lock);
buffer[sizeof(buffer)-1] = '\0';
ret = simple_read_from_buffer(u_data, count, off, buffer,
strlen(buffer));
if (ret <= 0)
return ret;
inode->i_atime = inode_set_ctime_current(inode);
return ret;
}
static int mqueue_flush_file(struct file *filp, fl_owner_t id)
{
struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
spin_lock(&info->lock);
if (task_tgid(current) == info->notify_owner)
remove_notification(info);
spin_unlock(&info->lock);
return 0;
}
static __poll_t mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
{
struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
__poll_t retval = 0;
poll_wait(filp, &info->wait_q, poll_tab);
spin_lock(&info->lock);
if (info->attr.mq_curmsgs)
retval = EPOLLIN | EPOLLRDNORM;
if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
retval |= EPOLLOUT | EPOLLWRNORM;
spin_unlock(&info->lock);
return retval;
}
/* Adds current to info->e_wait_q[sr] before element with smaller prio */
static void wq_add(struct mqueue_inode_info *info, int sr,
struct ext_wait_queue *ewp)
{
struct ext_wait_queue *walk;
list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
if (walk->task->prio <= current->prio) {
list_add_tail(&ewp->list, &walk->list);
return;
}
}
list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
}
/*
* Puts current task to sleep. Caller must hold queue lock. After return
* lock isn't held.
* sr: SEND or RECV
*/
static int wq_sleep(struct mqueue_inode_info *info, int sr,
ktime_t *timeout, struct ext_wait_queue *ewp)
__releases(&info->lock)
{
int retval;
signed long time;
wq_add(info, sr, ewp);
for (;;) {
/* memory barrier not required, we hold info->lock */
__set_current_state(TASK_INTERRUPTIBLE);
spin_unlock(&info->lock);
time = schedule_hrtimeout_range_clock(timeout, 0,
HRTIMER_MODE_ABS, CLOCK_REALTIME);
if (READ_ONCE(ewp->state) == STATE_READY) {
/* see MQ_BARRIER for purpose/pairing */
smp_acquire__after_ctrl_dep();
retval = 0;
goto out;
}
spin_lock(&info->lock);
/* we hold info->lock, so no memory barrier required */
if (READ_ONCE(ewp->state) == STATE_READY) {
retval = 0;
goto out_unlock;
}
if (signal_pending(current)) {
retval = -ERESTARTSYS;
break;
}
if (time == 0) {
retval = -ETIMEDOUT;
break;
}
}
list_del(&ewp->list);
out_unlock:
spin_unlock(&info->lock);
out:
return retval;
}
/*
* Returns waiting task that should be serviced first or NULL if none exists
*/
static struct ext_wait_queue *wq_get_first_waiter(
struct mqueue_inode_info *info, int sr)
{
struct list_head *ptr;
ptr = info->e_wait_q[sr].list.prev;
if (ptr == &info->e_wait_q[sr].list)
return NULL;
return list_entry(ptr, struct ext_wait_queue, list);
}
static inline void set_cookie(struct sk_buff *skb, char code)
{
((char *)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
}
/*
* The next function is only to split too long sys_mq_timedsend
*/
static void __do_notify(struct mqueue_inode_info *info)
{
/* notification
* invoked when there is registered process and there isn't process
* waiting synchronously for message AND state of queue changed from
* empty to not empty. Here we are sure that no one is waiting
* synchronously. */
if (info->notify_owner &&
info->attr.mq_curmsgs == 1) {
switch (info->notify.sigev_notify) {
case SIGEV_NONE:
break;
case SIGEV_SIGNAL: {
struct kernel_siginfo sig_i;
struct task_struct *task;
/* do_mq_notify() accepts sigev_signo == 0, why?? */
if (!info->notify.sigev_signo)
break;
clear_siginfo(&sig_i);
sig_i.si_signo = info->notify.sigev_signo;
sig_i.si_errno = 0;
sig_i.si_code = SI_MESGQ;
sig_i.si_value = info->notify.sigev_value;
rcu_read_lock();
/* map current pid/uid into info->owner's namespaces */
sig_i.si_pid = task_tgid_nr_ns(current,
ns_of_pid(info->notify_owner));
sig_i.si_uid = from_kuid_munged(info->notify_user_ns,
current_uid());
/*
* We can't use kill_pid_info(), this signal should
* bypass check_kill_permission(). It is from kernel
* but si_fromuser() can't know this.
* We do check the self_exec_id, to avoid sending
* signals to programs that don't expect them.
*/
task = pid_task(info->notify_owner, PIDTYPE_TGID);
if (task && task->self_exec_id ==
info->notify_self_exec_id) {
do_send_sig_info(info->notify.sigev_signo,
&sig_i, task, PIDTYPE_TGID);
}
rcu_read_unlock();
break;
}
case SIGEV_THREAD:
set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
netlink_sendskb(info->notify_sock, info->notify_cookie);
break;
}
/* after notification unregisters process */
put_pid(info->notify_owner);
put_user_ns(info->notify_user_ns);
info->notify_owner = NULL;
info->notify_user_ns = NULL;
}
wake_up(&info->wait_q);
}
static int prepare_timeout(const struct __kernel_timespec __user *u_abs_timeout,
struct timespec64 *ts)
{
if (get_timespec64(ts, u_abs_timeout))
return -EFAULT;
if (!timespec64_valid(ts))
return -EINVAL;
return 0;
}
static void remove_notification(struct mqueue_inode_info *info)
{
if (info->notify_owner != NULL &&
info->notify.sigev_notify == SIGEV_THREAD) {
set_cookie(info->notify_cookie, NOTIFY_REMOVED);
netlink_sendskb(info->notify_sock, info->notify_cookie);
}
put_pid(info->notify_owner);
put_user_ns(info->notify_user_ns);
info->notify_owner = NULL;
info->notify_user_ns = NULL;
}
static int prepare_open(struct dentry *dentry, int oflag, int ro,
umode_t mode, struct filename *name,
struct mq_attr *attr)
{
static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
MAY_READ | MAY_WRITE };
int acc;
if (d_really_is_negative(dentry)) {
if (!(oflag & O_CREAT))
return -ENOENT;
if (ro)
return ro;
audit_inode_parent_hidden(name, dentry->d_parent);
return vfs_mkobj(dentry, mode & ~current_umask(),
mqueue_create_attr, attr);
}
/* it already existed */
audit_inode(name, dentry, 0);
if ((oflag & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL))
return -EEXIST;
if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY))
return -EINVAL;
acc = oflag2acc[oflag & O_ACCMODE];
return inode_permission(&nop_mnt_idmap, d_inode(dentry), acc);
}
static int do_mq_open(const char __user *u_name, int oflag, umode_t mode,
struct mq_attr *attr)
{
struct vfsmount *mnt = current->nsproxy->ipc_ns->mq_mnt;
struct dentry *root = mnt->mnt_root;
struct filename *name;
struct path path;
int fd, error;
int ro;
audit_mq_open(oflag, mode, attr);
if (IS_ERR(name = getname(u_name)))
return PTR_ERR(name);
fd = get_unused_fd_flags(O_CLOEXEC);
if (fd < 0)
goto out_putname;
ro = mnt_want_write(mnt); /* we'll drop it in any case */
inode_lock(d_inode(root));
path.dentry = lookup_one_len(name->name, root, strlen(name->name));
if (IS_ERR(path.dentry)) {
error = PTR_ERR(path.dentry);
goto out_putfd;
}
path.mnt = mntget(mnt);
error = prepare_open(path.dentry, oflag, ro, mode, name, attr);
if (!error) {
struct file *file = dentry_open(&path, oflag, current_cred());
if (!IS_ERR(file))
fd_install(fd, file);
else
error = PTR_ERR(file);
}
path_put(&path);
out_putfd:
if (error) {
put_unused_fd(fd);
fd = error;
}
inode_unlock(d_inode(root));
if (!ro)
mnt_drop_write(mnt);
out_putname:
putname(name);
return fd;
}
SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
struct mq_attr __user *, u_attr)
{
struct mq_attr attr;
if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
return -EFAULT;
return do_mq_open(u_name, oflag, mode, u_attr ? &attr : NULL);
}
SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
{
int err;
struct filename *name;
struct dentry *dentry;
struct inode *inode = NULL;
struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
struct vfsmount *mnt = ipc_ns->mq_mnt;
name = getname(u_name);
if (IS_ERR(name))
return PTR_ERR(name);
audit_inode_parent_hidden(name, mnt->mnt_root);
err = mnt_want_write(mnt);
if (err)
goto out_name;
inode_lock_nested(d_inode(mnt->mnt_root), I_MUTEX_PARENT);
dentry = lookup_one_len(name->name, mnt->mnt_root,
strlen(name->name));
if (IS_ERR(dentry)) {
err = PTR_ERR(dentry);
goto out_unlock;
}
inode = d_inode(dentry);
if (!inode) {
err = -ENOENT;
} else {
ihold(inode);
err = vfs_unlink(&nop_mnt_idmap, d_inode(dentry->d_parent),
dentry, NULL);
}
dput(dentry);
out_unlock:
inode_unlock(d_inode(mnt->mnt_root));
iput(inode);
mnt_drop_write(mnt);
out_name:
putname(name);
return err;
}
/* Pipelined send and receive functions.
*
* If a receiver finds no waiting message, then it registers itself in the
* list of waiting receivers. A sender checks that list before adding the new
* message into the message array. If there is a waiting receiver, then it
* bypasses the message array and directly hands the message over to the
* receiver. The receiver accepts the message and returns without grabbing the
* queue spinlock:
*
* - Set pointer to message.
* - Queue the receiver task for later wakeup (without the info->lock).
* - Update its state to STATE_READY. Now the receiver can continue.
* - Wake up the process after the lock is dropped. Should the process wake up
* before this wakeup (due to a timeout or a signal) it will either see
* STATE_READY and continue or acquire the lock to check the state again.
*
* The same algorithm is used for senders.
*/
static inline void __pipelined_op(struct wake_q_head *wake_q,
struct mqueue_inode_info *info,
struct ext_wait_queue *this)
{
struct task_struct *task;
list_del(&this->list);
task = get_task_struct(this->task);
/* see MQ_BARRIER for purpose/pairing */
smp_store_release(&this->state, STATE_READY);
wake_q_add_safe(wake_q, task);
}
/* pipelined_send() - send a message directly to the task waiting in
* sys_mq_timedreceive() (without inserting message into a queue).
*/
static inline void pipelined_send(struct wake_q_head *wake_q,
struct mqueue_inode_info *info,
struct msg_msg *message,
struct ext_wait_queue *receiver)
{
receiver->msg = message;
__pipelined_op(wake_q, info, receiver);
}
/* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
* gets its message and put to the queue (we have one free place for sure). */
static inline void pipelined_receive(struct wake_q_head *wake_q,
struct mqueue_inode_info *info)
{
struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
if (!sender) {
/* for poll */
wake_up_interruptible(&info->wait_q);
return;
}
if (msg_insert(sender->msg, info))
return;
__pipelined_op(wake_q, info, sender);
}
static int do_mq_timedsend(mqd_t mqdes, const char __user *u_msg_ptr,
size_t msg_len, unsigned int msg_prio,
struct timespec64 *ts)
{
struct fd f;
struct inode *inode;
struct ext_wait_queue wait;
struct ext_wait_queue *receiver;
struct msg_msg *msg_ptr;
struct mqueue_inode_info *info;
ktime_t expires, *timeout = NULL;
struct posix_msg_tree_node *new_leaf = NULL;
int ret = 0;
DEFINE_WAKE_Q(wake_q);
if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
return -EINVAL;
if (ts) {
expires = timespec64_to_ktime(*ts);
timeout = &expires;
}
audit_mq_sendrecv(mqdes, msg_len, msg_prio, ts);
f = fdget(mqdes);
if (unlikely(!f.file)) {
ret = -EBADF;
goto out;
}
inode = file_inode(f.file);
if (unlikely(f.file->f_op != &mqueue_file_operations)) {
ret = -EBADF;
goto out_fput;
}
info = MQUEUE_I(inode);
audit_file(f.file);
if (unlikely(!(f.file->f_mode & FMODE_WRITE))) {
ret = -EBADF;
goto out_fput;
}
if (unlikely(msg_len > info->attr.mq_msgsize)) {
ret = -EMSGSIZE;
goto out_fput;
}
/* First try to allocate memory, before doing anything with
* existing queues. */
msg_ptr = load_msg(u_msg_ptr, msg_len);
if (IS_ERR(msg_ptr)) {
ret = PTR_ERR(msg_ptr);
goto out_fput;
}
msg_ptr->m_ts = msg_len;
msg_ptr->m_type = msg_prio;
/*
* msg_insert really wants us to have a valid, spare node struct so
* it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
* fall back to that if necessary.
*/
if (!info->node_cache)
new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
spin_lock(&info->lock);
if (!info->node_cache && new_leaf) {
/* Save our speculative allocation into the cache */
INIT_LIST_HEAD(&new_leaf->msg_list);
info->node_cache = new_leaf;
new_leaf = NULL;
} else {
kfree(new_leaf);
}
if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
if (f.file->f_flags & O_NONBLOCK) {
ret = -EAGAIN;
} else {
wait.task = current;
wait.msg = (void *) msg_ptr;
/* memory barrier not required, we hold info->lock */
WRITE_ONCE(wait.state, STATE_NONE);
ret = wq_sleep(info, SEND, timeout, &wait);
/*
* wq_sleep must be called with info->lock held, and
* returns with the lock released
*/
goto out_free;
}
} else {
receiver = wq_get_first_waiter(info, RECV);
if (receiver) {
pipelined_send(&wake_q, info, msg_ptr, receiver);
} else {
/* adds message to the queue */
ret = msg_insert(msg_ptr, info);
if (ret)
goto out_unlock;
__do_notify(info);
}
inode->i_atime = inode->i_mtime = inode_set_ctime_current(inode);
}
out_unlock:
spin_unlock(&info->lock);
wake_up_q(&wake_q);
out_free:
if (ret)
free_msg(msg_ptr);
out_fput:
fdput(f);
out:
return ret;
}
static int do_mq_timedreceive(mqd_t mqdes, char __user *u_msg_ptr,
size_t msg_len, unsigned int __user *u_msg_prio,
struct timespec64 *ts)
{
ssize_t ret;
struct msg_msg *msg_ptr;
struct fd f;
struct inode *inode;
struct mqueue_inode_info *info;
struct ext_wait_queue wait;
ktime_t expires, *timeout = NULL;
struct posix_msg_tree_node *new_leaf = NULL;
if (ts) {
expires = timespec64_to_ktime(*ts);
timeout = &expires;
}
audit_mq_sendrecv(mqdes, msg_len, 0, ts);
f = fdget(mqdes);
if (unlikely(!f.file)) {
ret = -EBADF;
goto out;
}
inode = file_inode(f.file);
if (unlikely(f.file->f_op != &mqueue_file_operations)) {
ret = -EBADF;
goto out_fput;
}
info = MQUEUE_I(inode);
audit_file(f.file);
if (unlikely(!(f.file->f_mode & FMODE_READ))) {
ret = -EBADF;
goto out_fput;
}
/* checks if buffer is big enough */
if (unlikely(msg_len < info->attr.mq_msgsize)) {
ret = -EMSGSIZE;
goto out_fput;
}
/*
* msg_insert really wants us to have a valid, spare node struct so
* it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
* fall back to that if necessary.
*/
if (!info->node_cache)
new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
spin_lock(&info->lock);
if (!info->node_cache && new_leaf) {
/* Save our speculative allocation into the cache */
INIT_LIST_HEAD(&new_leaf->msg_list);
info->node_cache = new_leaf;
} else {
kfree(new_leaf);
}
if (info->attr.mq_curmsgs == 0) {
if (f.file->f_flags & O_NONBLOCK) {
spin_unlock(&info->lock);
ret = -EAGAIN;
} else {
wait.task = current;
/* memory barrier not required, we hold info->lock */
WRITE_ONCE(wait.state, STATE_NONE);
ret = wq_sleep(info, RECV, timeout, &wait);
msg_ptr = wait.msg;
}
} else {
DEFINE_WAKE_Q(wake_q);
msg_ptr = msg_get(info);
inode->i_atime = inode->i_mtime = inode_set_ctime_current(inode);
/* There is now free space in queue. */
pipelined_receive(&wake_q, info);
spin_unlock(&info->lock);
wake_up_q(&wake_q);
ret = 0;
}
if (ret == 0) {
ret = msg_ptr->m_ts;
if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
ret = -EFAULT;
}
free_msg(msg_ptr);
}
out_fput:
fdput(f);
out:
return ret;
}
SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
size_t, msg_len, unsigned int, msg_prio,
const struct __kernel_timespec __user *, u_abs_timeout)
{
struct timespec64 ts, *p = NULL;
if (u_abs_timeout) {
int res = prepare_timeout(u_abs_timeout, &ts);
if (res)
return res;
p = &ts;
}
return do_mq_timedsend(mqdes, u_msg_ptr, msg_len, msg_prio, p);
}
SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
size_t, msg_len, unsigned int __user *, u_msg_prio,
const struct __kernel_timespec __user *, u_abs_timeout)
{
struct timespec64 ts, *p = NULL;
if (u_abs_timeout) {
int res = prepare_timeout(u_abs_timeout, &ts);
if (res)
return res;
p = &ts;
}
return do_mq_timedreceive(mqdes, u_msg_ptr, msg_len, u_msg_prio, p);
}
/*
* Notes: the case when user wants us to deregister (with NULL as pointer)
* and he isn't currently owner of notification, will be silently discarded.
* It isn't explicitly defined in the POSIX.
*/
static int do_mq_notify(mqd_t mqdes, const struct sigevent *notification)
{
int ret;
struct fd f;
struct sock *sock;
struct inode *inode;
struct mqueue_inode_info *info;
struct sk_buff *nc;
audit_mq_notify(mqdes, notification);
nc = NULL;
sock = NULL;
if (notification != NULL) {
if (unlikely(notification->sigev_notify != SIGEV_NONE &&
notification->sigev_notify != SIGEV_SIGNAL &&
notification->sigev_notify != SIGEV_THREAD))
return -EINVAL;
if (notification->sigev_notify == SIGEV_SIGNAL &&
!valid_signal(notification->sigev_signo)) {
return -EINVAL;
}
if (notification->sigev_notify == SIGEV_THREAD) {
long timeo;
/* create the notify skb */
nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
if (!nc)
return -ENOMEM;
if (copy_from_user(nc->data,
notification->sigev_value.sival_ptr,
NOTIFY_COOKIE_LEN)) {
ret = -EFAULT;
goto free_skb;
}
/* TODO: add a header? */
skb_put(nc, NOTIFY_COOKIE_LEN);
/* and attach it to the socket */
retry:
f = fdget(notification->sigev_signo);
if (!f.file) {
ret = -EBADF;
goto out;
}
sock = netlink_getsockbyfilp(f.file);
fdput(f);
if (IS_ERR(sock)) {
ret = PTR_ERR(sock);
goto free_skb;
}
timeo = MAX_SCHEDULE_TIMEOUT;
ret = netlink_attachskb(sock, nc, &timeo, NULL);
if (ret == 1) {
sock = NULL;
goto retry;
}
if (ret)
return ret;
}
}
f = fdget(mqdes);
if (!f.file) {
ret = -EBADF;
goto out;
}
inode = file_inode(f.file);
if (unlikely(f.file->f_op != &mqueue_file_operations)) {
ret = -EBADF;
goto out_fput;
}
info = MQUEUE_I(inode);
ret = 0;
spin_lock(&info->lock);
if (notification == NULL) {
if (info->notify_owner == task_tgid(current)) {
remove_notification(info);
inode->i_atime = inode_set_ctime_current(inode);
}
} else if (info->notify_owner != NULL) {
ret = -EBUSY;
} else {
switch (notification->sigev_notify) {
case SIGEV_NONE:
info->notify.sigev_notify = SIGEV_NONE;
break;
case SIGEV_THREAD:
info->notify_sock = sock;
info->notify_cookie = nc;
sock = NULL;
nc = NULL;
info->notify.sigev_notify = SIGEV_THREAD;
break;
case SIGEV_SIGNAL:
info->notify.sigev_signo = notification->sigev_signo;
info->notify.sigev_value = notification->sigev_value;
info->notify.sigev_notify = SIGEV_SIGNAL;
info->notify_self_exec_id = current->self_exec_id;
break;
}
info->notify_owner = get_pid(task_tgid(current));
info->notify_user_ns = get_user_ns(current_user_ns());
inode->i_atime = inode_set_ctime_current(inode);
}
spin_unlock(&info->lock);
out_fput:
fdput(f);
out:
if (sock)
netlink_detachskb(sock, nc);
else
free_skb:
dev_kfree_skb(nc);
return ret;
}
SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
const struct sigevent __user *, u_notification)
{
struct sigevent n, *p = NULL;
if (u_notification) {
if (copy_from_user(&n, u_notification, sizeof(struct sigevent)))
return -EFAULT;
p = &n;
}
return do_mq_notify(mqdes, p);
}
static int do_mq_getsetattr(int mqdes, struct mq_attr *new, struct mq_attr *old)
{
struct fd f;
struct inode *inode;
struct mqueue_inode_info *info;
if (new && (new->mq_flags & (~O_NONBLOCK)))
return -EINVAL;
f = fdget(mqdes);
if (!f.file)
return -EBADF;
if (unlikely(f.file->f_op != &mqueue_file_operations)) {
fdput(f);
return -EBADF;
}
inode = file_inode(f.file);
info = MQUEUE_I(inode);
spin_lock(&info->lock);
if (old) {
*old = info->attr;
old->mq_flags = f.file->f_flags & O_NONBLOCK;
}
if (new) {
audit_mq_getsetattr(mqdes, new);
spin_lock(&f.file->f_lock);
if (new->mq_flags & O_NONBLOCK)
f.file->f_flags |= O_NONBLOCK;
else
f.file->f_flags &= ~O_NONBLOCK;
spin_unlock(&f.file->f_lock);
inode->i_atime = inode_set_ctime_current(inode);
}
spin_unlock(&info->lock);
fdput(f);
return 0;
}
SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
const struct mq_attr __user *, u_mqstat,
struct mq_attr __user *, u_omqstat)
{
int ret;
struct mq_attr mqstat, omqstat;
struct mq_attr *new = NULL, *old = NULL;
if (u_mqstat) {
new = &mqstat;
if (copy_from_user(new, u_mqstat, sizeof(struct mq_attr)))
return -EFAULT;
}
if (u_omqstat)
old = &omqstat;
ret = do_mq_getsetattr(mqdes, new, old);
if (ret || !old)
return ret;
if (copy_to_user(u_omqstat, old, sizeof(struct mq_attr)))
return -EFAULT;
return 0;
}
#ifdef CONFIG_COMPAT
struct compat_mq_attr {
compat_long_t mq_flags; /* message queue flags */
compat_long_t mq_maxmsg; /* maximum number of messages */
compat_long_t mq_msgsize; /* maximum message size */
compat_long_t mq_curmsgs; /* number of messages currently queued */
compat_long_t __reserved[4]; /* ignored for input, zeroed for output */
};
static inline int get_compat_mq_attr(struct mq_attr *attr,
const struct compat_mq_attr __user *uattr)
{
struct compat_mq_attr v;
if (copy_from_user(&v, uattr, sizeof(*uattr)))
return -EFAULT;
memset(attr, 0, sizeof(*attr));
attr->mq_flags = v.mq_flags;
attr->mq_maxmsg = v.mq_maxmsg;
attr->mq_msgsize = v.mq_msgsize;
attr->mq_curmsgs = v.mq_curmsgs;
return 0;
}
static inline int put_compat_mq_attr(const struct mq_attr *attr,
struct compat_mq_attr __user *uattr)
{
struct compat_mq_attr v;
memset(&v, 0, sizeof(v));
v.mq_flags = attr->mq_flags;
v.mq_maxmsg = attr->mq_maxmsg;
v.mq_msgsize = attr->mq_msgsize;
v.mq_curmsgs = attr->mq_curmsgs;
if (copy_to_user(uattr, &v, sizeof(*uattr)))
return -EFAULT;
return 0;
}
COMPAT_SYSCALL_DEFINE4(mq_open, const char __user *, u_name,
int, oflag, compat_mode_t, mode,
struct compat_mq_attr __user *, u_attr)
{
struct mq_attr attr, *p = NULL;
if (u_attr && oflag & O_CREAT) {
p = &attr;
if (get_compat_mq_attr(&attr, u_attr))
return -EFAULT;
}
return do_mq_open(u_name, oflag, mode, p);
}
COMPAT_SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
const struct compat_sigevent __user *, u_notification)
{
struct sigevent n, *p = NULL;
if (u_notification) {
if (get_compat_sigevent(&n, u_notification))
return -EFAULT;
if (n.sigev_notify == SIGEV_THREAD)
n.sigev_value.sival_ptr = compat_ptr(n.sigev_value.sival_int);
p = &n;
}
return do_mq_notify(mqdes, p);
}
COMPAT_SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
const struct compat_mq_attr __user *, u_mqstat,
struct compat_mq_attr __user *, u_omqstat)
{
int ret;
struct mq_attr mqstat, omqstat;
struct mq_attr *new = NULL, *old = NULL;
if (u_mqstat) {
new = &mqstat;
if (get_compat_mq_attr(new, u_mqstat))
return -EFAULT;
}
if (u_omqstat)
old = &omqstat;
ret = do_mq_getsetattr(mqdes, new, old);
if (ret || !old)
return ret;
if (put_compat_mq_attr(old, u_omqstat))
return -EFAULT;
return 0;
}
#endif
#ifdef CONFIG_COMPAT_32BIT_TIME
static int compat_prepare_timeout(const struct old_timespec32 __user *p,
struct timespec64 *ts)
{
if (get_old_timespec32(ts, p))
return -EFAULT;
if (!timespec64_valid(ts))
return -EINVAL;
return 0;
}
SYSCALL_DEFINE5(mq_timedsend_time32, mqd_t, mqdes,
const char __user *, u_msg_ptr,
unsigned int, msg_len, unsigned int, msg_prio,
const struct old_timespec32 __user *, u_abs_timeout)
{
struct timespec64 ts, *p = NULL;
if (u_abs_timeout) {
int res = compat_prepare_timeout(u_abs_timeout, &ts);
if (res)
return res;
p = &ts;
}
return do_mq_timedsend(mqdes, u_msg_ptr, msg_len, msg_prio, p);
}
SYSCALL_DEFINE5(mq_timedreceive_time32, mqd_t, mqdes,
char __user *, u_msg_ptr,
unsigned int, msg_len, unsigned int __user *, u_msg_prio,
const struct old_timespec32 __user *, u_abs_timeout)
{
struct timespec64 ts, *p = NULL;
if (u_abs_timeout) {
int res = compat_prepare_timeout(u_abs_timeout, &ts);
if (res)
return res;
p = &ts;
}
return do_mq_timedreceive(mqdes, u_msg_ptr, msg_len, u_msg_prio, p);
}
#endif
static const struct inode_operations mqueue_dir_inode_operations = {
.lookup = simple_lookup,
.create = mqueue_create,
.unlink = mqueue_unlink,
};
static const struct file_operations mqueue_file_operations = {
.flush = mqueue_flush_file,
.poll = mqueue_poll_file,
.read = mqueue_read_file,
.llseek = default_llseek,
};
static const struct super_operations mqueue_super_ops = {
.alloc_inode = mqueue_alloc_inode,
.free_inode = mqueue_free_inode,
.evict_inode = mqueue_evict_inode,
.statfs = simple_statfs,
};
static const struct fs_context_operations mqueue_fs_context_ops = {
.free = mqueue_fs_context_free,
.get_tree = mqueue_get_tree,
};
static struct file_system_type mqueue_fs_type = {
.name = "mqueue",
.init_fs_context = mqueue_init_fs_context,
.kill_sb = kill_litter_super,
.fs_flags = FS_USERNS_MOUNT,
};
int mq_init_ns(struct ipc_namespace *ns)
{
struct vfsmount *m;
ns->mq_queues_count = 0;
ns->mq_queues_max = DFLT_QUEUESMAX;
ns->mq_msg_max = DFLT_MSGMAX;
ns->mq_msgsize_max = DFLT_MSGSIZEMAX;
ns->mq_msg_default = DFLT_MSG;
ns->mq_msgsize_default = DFLT_MSGSIZE;
m = mq_create_mount(ns);
if (IS_ERR(m))
return PTR_ERR(m);
ns->mq_mnt = m;
return 0;
}
void mq_clear_sbinfo(struct ipc_namespace *ns)
{
ns->mq_mnt->mnt_sb->s_fs_info = NULL;
}
static int __init init_mqueue_fs(void)
{
int error;
mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
sizeof(struct mqueue_inode_info), 0,
SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT, init_once);
if (mqueue_inode_cachep == NULL)
return -ENOMEM;
if (!setup_mq_sysctls(&init_ipc_ns)) {
pr_warn("sysctl registration failed\n");
error = -ENOMEM;
goto out_kmem;
}
error = register_filesystem(&mqueue_fs_type);
if (error)
goto out_sysctl;
spin_lock_init(&mq_lock);
error = mq_init_ns(&init_ipc_ns);
if (error)
goto out_filesystem;
return 0;
out_filesystem:
unregister_filesystem(&mqueue_fs_type);
out_sysctl:
retire_mq_sysctls(&init_ipc_ns);
out_kmem:
kmem_cache_destroy(mqueue_inode_cachep);
return error;
}
device_initcall(init_mqueue_fs);
| linux-master | ipc/mqueue.c |
// SPDX-License-Identifier: GPL-2.0
/*
* linux/ipc/namespace.c
* Copyright (C) 2006 Pavel Emelyanov <[email protected]> OpenVZ, SWsoft Inc.
*/
#include <linux/ipc.h>
#include <linux/msg.h>
#include <linux/ipc_namespace.h>
#include <linux/rcupdate.h>
#include <linux/nsproxy.h>
#include <linux/slab.h>
#include <linux/cred.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/user_namespace.h>
#include <linux/proc_ns.h>
#include <linux/sched/task.h>
#include "util.h"
/*
* The work queue is used to avoid the cost of synchronize_rcu in kern_unmount.
*/
static void free_ipc(struct work_struct *unused);
static DECLARE_WORK(free_ipc_work, free_ipc);
static struct ucounts *inc_ipc_namespaces(struct user_namespace *ns)
{
return inc_ucount(ns, current_euid(), UCOUNT_IPC_NAMESPACES);
}
static void dec_ipc_namespaces(struct ucounts *ucounts)
{
dec_ucount(ucounts, UCOUNT_IPC_NAMESPACES);
}
static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns,
struct ipc_namespace *old_ns)
{
struct ipc_namespace *ns;
struct ucounts *ucounts;
int err;
err = -ENOSPC;
again:
ucounts = inc_ipc_namespaces(user_ns);
if (!ucounts) {
/*
* IPC namespaces are freed asynchronously, by free_ipc_work.
* If frees were pending, flush_work will wait, and
* return true. Fail the allocation if no frees are pending.
*/
if (flush_work(&free_ipc_work))
goto again;
goto fail;
}
err = -ENOMEM;
ns = kzalloc(sizeof(struct ipc_namespace), GFP_KERNEL_ACCOUNT);
if (ns == NULL)
goto fail_dec;
err = ns_alloc_inum(&ns->ns);
if (err)
goto fail_free;
ns->ns.ops = &ipcns_operations;
refcount_set(&ns->ns.count, 1);
ns->user_ns = get_user_ns(user_ns);
ns->ucounts = ucounts;
err = mq_init_ns(ns);
if (err)
goto fail_put;
err = -ENOMEM;
if (!setup_mq_sysctls(ns))
goto fail_put;
if (!setup_ipc_sysctls(ns))
goto fail_mq;
err = msg_init_ns(ns);
if (err)
goto fail_put;
sem_init_ns(ns);
shm_init_ns(ns);
return ns;
fail_mq:
retire_mq_sysctls(ns);
fail_put:
put_user_ns(ns->user_ns);
ns_free_inum(&ns->ns);
fail_free:
kfree(ns);
fail_dec:
dec_ipc_namespaces(ucounts);
fail:
return ERR_PTR(err);
}
struct ipc_namespace *copy_ipcs(unsigned long flags,
struct user_namespace *user_ns, struct ipc_namespace *ns)
{
if (!(flags & CLONE_NEWIPC))
return get_ipc_ns(ns);
return create_ipc_ns(user_ns, ns);
}
/*
* free_ipcs - free all ipcs of one type
* @ns: the namespace to remove the ipcs from
* @ids: the table of ipcs to free
* @free: the function called to free each individual ipc
*
* Called for each kind of ipc when an ipc_namespace exits.
*/
void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
void (*free)(struct ipc_namespace *, struct kern_ipc_perm *))
{
struct kern_ipc_perm *perm;
int next_id;
int total, in_use;
down_write(&ids->rwsem);
in_use = ids->in_use;
for (total = 0, next_id = 0; total < in_use; next_id++) {
perm = idr_find(&ids->ipcs_idr, next_id);
if (perm == NULL)
continue;
rcu_read_lock();
ipc_lock_object(perm);
free(ns, perm);
total++;
}
up_write(&ids->rwsem);
}
static void free_ipc_ns(struct ipc_namespace *ns)
{
/*
* Caller needs to wait for an RCU grace period to have passed
* after making the mount point inaccessible to new accesses.
*/
mntput(ns->mq_mnt);
sem_exit_ns(ns);
msg_exit_ns(ns);
shm_exit_ns(ns);
retire_mq_sysctls(ns);
retire_ipc_sysctls(ns);
dec_ipc_namespaces(ns->ucounts);
put_user_ns(ns->user_ns);
ns_free_inum(&ns->ns);
kfree(ns);
}
static LLIST_HEAD(free_ipc_list);
static void free_ipc(struct work_struct *unused)
{
struct llist_node *node = llist_del_all(&free_ipc_list);
struct ipc_namespace *n, *t;
llist_for_each_entry_safe(n, t, node, mnt_llist)
mnt_make_shortterm(n->mq_mnt);
/* Wait for any last users to have gone away. */
synchronize_rcu();
llist_for_each_entry_safe(n, t, node, mnt_llist)
free_ipc_ns(n);
}
/*
* put_ipc_ns - drop a reference to an ipc namespace.
* @ns: the namespace to put
*
* If this is the last task in the namespace exiting, and
* it is dropping the refcount to 0, then it can race with
* a task in another ipc namespace but in a mounts namespace
* which has this ipcns's mqueuefs mounted, doing some action
* with one of the mqueuefs files. That can raise the refcount.
* So dropping the refcount, and raising the refcount when
* accessing it through the VFS, are protected with mq_lock.
*
* (Clearly, a task raising the refcount on its own ipc_ns
* needn't take mq_lock since it can't race with the last task
* in the ipcns exiting).
*/
void put_ipc_ns(struct ipc_namespace *ns)
{
if (refcount_dec_and_lock(&ns->ns.count, &mq_lock)) {
mq_clear_sbinfo(ns);
spin_unlock(&mq_lock);
if (llist_add(&ns->mnt_llist, &free_ipc_list))
schedule_work(&free_ipc_work);
}
}
static inline struct ipc_namespace *to_ipc_ns(struct ns_common *ns)
{
return container_of(ns, struct ipc_namespace, ns);
}
static struct ns_common *ipcns_get(struct task_struct *task)
{
struct ipc_namespace *ns = NULL;
struct nsproxy *nsproxy;
task_lock(task);
nsproxy = task->nsproxy;
if (nsproxy)
ns = get_ipc_ns(nsproxy->ipc_ns);
task_unlock(task);
return ns ? &ns->ns : NULL;
}
static void ipcns_put(struct ns_common *ns)
{
return put_ipc_ns(to_ipc_ns(ns));
}
static int ipcns_install(struct nsset *nsset, struct ns_common *new)
{
struct nsproxy *nsproxy = nsset->nsproxy;
struct ipc_namespace *ns = to_ipc_ns(new);
if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) ||
!ns_capable(nsset->cred->user_ns, CAP_SYS_ADMIN))
return -EPERM;
put_ipc_ns(nsproxy->ipc_ns);
nsproxy->ipc_ns = get_ipc_ns(ns);
return 0;
}
static struct user_namespace *ipcns_owner(struct ns_common *ns)
{
return to_ipc_ns(ns)->user_ns;
}
const struct proc_ns_operations ipcns_operations = {
.name = "ipc",
.type = CLONE_NEWIPC,
.get = ipcns_get,
.put = ipcns_put,
.install = ipcns_install,
.owner = ipcns_owner,
};
| linux-master | ipc/namespace.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/file.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/nospec.h>
#include <linux/io_uring.h>
#include <uapi/linux/io_uring.h>
#include "io_uring.h"
#include "rsrc.h"
#include "filetable.h"
static int io_file_bitmap_get(struct io_ring_ctx *ctx)
{
struct io_file_table *table = &ctx->file_table;
unsigned long nr = ctx->file_alloc_end;
int ret;
if (!table->bitmap)
return -ENFILE;
do {
ret = find_next_zero_bit(table->bitmap, nr, table->alloc_hint);
if (ret != nr)
return ret;
if (table->alloc_hint == ctx->file_alloc_start)
break;
nr = table->alloc_hint;
table->alloc_hint = ctx->file_alloc_start;
} while (1);
return -ENFILE;
}
bool io_alloc_file_tables(struct io_file_table *table, unsigned nr_files)
{
table->files = kvcalloc(nr_files, sizeof(table->files[0]),
GFP_KERNEL_ACCOUNT);
if (unlikely(!table->files))
return false;
table->bitmap = bitmap_zalloc(nr_files, GFP_KERNEL_ACCOUNT);
if (unlikely(!table->bitmap)) {
kvfree(table->files);
return false;
}
return true;
}
void io_free_file_tables(struct io_file_table *table)
{
kvfree(table->files);
bitmap_free(table->bitmap);
table->files = NULL;
table->bitmap = NULL;
}
static int io_install_fixed_file(struct io_ring_ctx *ctx, struct file *file,
u32 slot_index)
__must_hold(&req->ctx->uring_lock)
{
struct io_fixed_file *file_slot;
int ret;
if (io_is_uring_fops(file))
return -EBADF;
if (!ctx->file_data)
return -ENXIO;
if (slot_index >= ctx->nr_user_files)
return -EINVAL;
slot_index = array_index_nospec(slot_index, ctx->nr_user_files);
file_slot = io_fixed_file_slot(&ctx->file_table, slot_index);
if (file_slot->file_ptr) {
ret = io_queue_rsrc_removal(ctx->file_data, slot_index,
io_slot_file(file_slot));
if (ret)
return ret;
file_slot->file_ptr = 0;
io_file_bitmap_clear(&ctx->file_table, slot_index);
}
ret = io_scm_file_account(ctx, file);
if (!ret) {
*io_get_tag_slot(ctx->file_data, slot_index) = 0;
io_fixed_file_set(file_slot, file);
io_file_bitmap_set(&ctx->file_table, slot_index);
}
return ret;
}
int __io_fixed_fd_install(struct io_ring_ctx *ctx, struct file *file,
unsigned int file_slot)
{
bool alloc_slot = file_slot == IORING_FILE_INDEX_ALLOC;
int ret;
if (alloc_slot) {
ret = io_file_bitmap_get(ctx);
if (unlikely(ret < 0))
return ret;
file_slot = ret;
} else {
file_slot--;
}
ret = io_install_fixed_file(ctx, file, file_slot);
if (!ret && alloc_slot)
ret = file_slot;
return ret;
}
/*
* Note when io_fixed_fd_install() returns error value, it will ensure
* fput() is called correspondingly.
*/
int io_fixed_fd_install(struct io_kiocb *req, unsigned int issue_flags,
struct file *file, unsigned int file_slot)
{
struct io_ring_ctx *ctx = req->ctx;
int ret;
io_ring_submit_lock(ctx, issue_flags);
ret = __io_fixed_fd_install(ctx, file, file_slot);
io_ring_submit_unlock(ctx, issue_flags);
if (unlikely(ret < 0))
fput(file);
return ret;
}
int io_fixed_fd_remove(struct io_ring_ctx *ctx, unsigned int offset)
{
struct io_fixed_file *file_slot;
int ret;
if (unlikely(!ctx->file_data))
return -ENXIO;
if (offset >= ctx->nr_user_files)
return -EINVAL;
offset = array_index_nospec(offset, ctx->nr_user_files);
file_slot = io_fixed_file_slot(&ctx->file_table, offset);
if (!file_slot->file_ptr)
return -EBADF;
ret = io_queue_rsrc_removal(ctx->file_data, offset,
io_slot_file(file_slot));
if (ret)
return ret;
file_slot->file_ptr = 0;
io_file_bitmap_clear(&ctx->file_table, offset);
return 0;
}
int io_register_file_alloc_range(struct io_ring_ctx *ctx,
struct io_uring_file_index_range __user *arg)
{
struct io_uring_file_index_range range;
u32 end;
if (copy_from_user(&range, arg, sizeof(range)))
return -EFAULT;
if (check_add_overflow(range.off, range.len, &end))
return -EOVERFLOW;
if (range.resv || end > ctx->nr_user_files)
return -EINVAL;
io_file_table_set_alloc_range(ctx, range.off, range.len);
return 0;
}
| linux-master | io_uring/filetable.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Shared application/kernel submission and completion ring pairs, for
* supporting fast/efficient IO.
*
* A note on the read/write ordering memory barriers that are matched between
* the application and kernel side.
*
* After the application reads the CQ ring tail, it must use an
* appropriate smp_rmb() to pair with the smp_wmb() the kernel uses
* before writing the tail (using smp_load_acquire to read the tail will
* do). It also needs a smp_mb() before updating CQ head (ordering the
* entry load(s) with the head store), pairing with an implicit barrier
* through a control-dependency in io_get_cqe (smp_store_release to
* store head will do). Failure to do so could lead to reading invalid
* CQ entries.
*
* Likewise, the application must use an appropriate smp_wmb() before
* writing the SQ tail (ordering SQ entry stores with the tail store),
* which pairs with smp_load_acquire in io_get_sqring (smp_store_release
* to store the tail will do). And it needs a barrier ordering the SQ
* head load before writing new SQ entries (smp_load_acquire to read
* head will do).
*
* When using the SQ poll thread (IORING_SETUP_SQPOLL), the application
* needs to check the SQ flags for IORING_SQ_NEED_WAKEUP *after*
* updating the SQ tail; a full memory barrier smp_mb() is needed
* between.
*
* Also see the examples in the liburing library:
*
* git://git.kernel.dk/liburing
*
* io_uring also uses READ/WRITE_ONCE() for _any_ store or load that happens
* from data shared between the kernel and application. This is done both
* for ordering purposes, but also to ensure that once a value is loaded from
* data that the application could potentially modify, it remains stable.
*
* Copyright (C) 2018-2019 Jens Axboe
* Copyright (c) 2018-2019 Christoph Hellwig
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/syscalls.h>
#include <net/compat.h>
#include <linux/refcount.h>
#include <linux/uio.h>
#include <linux/bits.h>
#include <linux/sched/signal.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/fdtable.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/percpu.h>
#include <linux/slab.h>
#include <linux/bvec.h>
#include <linux/net.h>
#include <net/sock.h>
#include <net/af_unix.h>
#include <net/scm.h>
#include <linux/anon_inodes.h>
#include <linux/sched/mm.h>
#include <linux/uaccess.h>
#include <linux/nospec.h>
#include <linux/highmem.h>
#include <linux/fsnotify.h>
#include <linux/fadvise.h>
#include <linux/task_work.h>
#include <linux/io_uring.h>
#include <linux/audit.h>
#include <linux/security.h>
#include <asm/shmparam.h>
#define CREATE_TRACE_POINTS
#include <trace/events/io_uring.h>
#include <uapi/linux/io_uring.h>
#include "io-wq.h"
#include "io_uring.h"
#include "opdef.h"
#include "refs.h"
#include "tctx.h"
#include "sqpoll.h"
#include "fdinfo.h"
#include "kbuf.h"
#include "rsrc.h"
#include "cancel.h"
#include "net.h"
#include "notif.h"
#include "timeout.h"
#include "poll.h"
#include "rw.h"
#include "alloc_cache.h"
#define IORING_MAX_ENTRIES 32768
#define IORING_MAX_CQ_ENTRIES (2 * IORING_MAX_ENTRIES)
#define IORING_MAX_RESTRICTIONS (IORING_RESTRICTION_LAST + \
IORING_REGISTER_LAST + IORING_OP_LAST)
#define SQE_COMMON_FLAGS (IOSQE_FIXED_FILE | IOSQE_IO_LINK | \
IOSQE_IO_HARDLINK | IOSQE_ASYNC)
#define SQE_VALID_FLAGS (SQE_COMMON_FLAGS | IOSQE_BUFFER_SELECT | \
IOSQE_IO_DRAIN | IOSQE_CQE_SKIP_SUCCESS)
#define IO_REQ_CLEAN_FLAGS (REQ_F_BUFFER_SELECTED | REQ_F_NEED_CLEANUP | \
REQ_F_POLLED | REQ_F_INFLIGHT | REQ_F_CREDS | \
REQ_F_ASYNC_DATA)
#define IO_REQ_CLEAN_SLOW_FLAGS (REQ_F_REFCOUNT | REQ_F_LINK | REQ_F_HARDLINK |\
IO_REQ_CLEAN_FLAGS)
#define IO_TCTX_REFS_CACHE_NR (1U << 10)
#define IO_COMPL_BATCH 32
#define IO_REQ_ALLOC_BATCH 8
enum {
IO_CHECK_CQ_OVERFLOW_BIT,
IO_CHECK_CQ_DROPPED_BIT,
};
enum {
IO_EVENTFD_OP_SIGNAL_BIT,
IO_EVENTFD_OP_FREE_BIT,
};
struct io_defer_entry {
struct list_head list;
struct io_kiocb *req;
u32 seq;
};
/* requests with any of those set should undergo io_disarm_next() */
#define IO_DISARM_MASK (REQ_F_ARM_LTIMEOUT | REQ_F_LINK_TIMEOUT | REQ_F_FAIL)
#define IO_REQ_LINK_FLAGS (REQ_F_LINK | REQ_F_HARDLINK)
static bool io_uring_try_cancel_requests(struct io_ring_ctx *ctx,
struct task_struct *task,
bool cancel_all);
static void io_queue_sqe(struct io_kiocb *req);
struct kmem_cache *req_cachep;
static int __read_mostly sysctl_io_uring_disabled;
static int __read_mostly sysctl_io_uring_group = -1;
#ifdef CONFIG_SYSCTL
static struct ctl_table kernel_io_uring_disabled_table[] = {
{
.procname = "io_uring_disabled",
.data = &sysctl_io_uring_disabled,
.maxlen = sizeof(sysctl_io_uring_disabled),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_TWO,
},
{
.procname = "io_uring_group",
.data = &sysctl_io_uring_group,
.maxlen = sizeof(gid_t),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{},
};
#endif
struct sock *io_uring_get_socket(struct file *file)
{
#if defined(CONFIG_UNIX)
if (io_is_uring_fops(file)) {
struct io_ring_ctx *ctx = file->private_data;
return ctx->ring_sock->sk;
}
#endif
return NULL;
}
EXPORT_SYMBOL(io_uring_get_socket);
static inline void io_submit_flush_completions(struct io_ring_ctx *ctx)
{
if (!wq_list_empty(&ctx->submit_state.compl_reqs) ||
ctx->submit_state.cqes_count)
__io_submit_flush_completions(ctx);
}
static inline unsigned int __io_cqring_events(struct io_ring_ctx *ctx)
{
return ctx->cached_cq_tail - READ_ONCE(ctx->rings->cq.head);
}
static inline unsigned int __io_cqring_events_user(struct io_ring_ctx *ctx)
{
return READ_ONCE(ctx->rings->cq.tail) - READ_ONCE(ctx->rings->cq.head);
}
static bool io_match_linked(struct io_kiocb *head)
{
struct io_kiocb *req;
io_for_each_link(req, head) {
if (req->flags & REQ_F_INFLIGHT)
return true;
}
return false;
}
/*
* As io_match_task() but protected against racing with linked timeouts.
* User must not hold timeout_lock.
*/
bool io_match_task_safe(struct io_kiocb *head, struct task_struct *task,
bool cancel_all)
{
bool matched;
if (task && head->task != task)
return false;
if (cancel_all)
return true;
if (head->flags & REQ_F_LINK_TIMEOUT) {
struct io_ring_ctx *ctx = head->ctx;
/* protect against races with linked timeouts */
spin_lock_irq(&ctx->timeout_lock);
matched = io_match_linked(head);
spin_unlock_irq(&ctx->timeout_lock);
} else {
matched = io_match_linked(head);
}
return matched;
}
static inline void req_fail_link_node(struct io_kiocb *req, int res)
{
req_set_fail(req);
io_req_set_res(req, res, 0);
}
static inline void io_req_add_to_cache(struct io_kiocb *req, struct io_ring_ctx *ctx)
{
wq_stack_add_head(&req->comp_list, &ctx->submit_state.free_list);
}
static __cold void io_ring_ctx_ref_free(struct percpu_ref *ref)
{
struct io_ring_ctx *ctx = container_of(ref, struct io_ring_ctx, refs);
complete(&ctx->ref_comp);
}
static __cold void io_fallback_req_func(struct work_struct *work)
{
struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx,
fallback_work.work);
struct llist_node *node = llist_del_all(&ctx->fallback_llist);
struct io_kiocb *req, *tmp;
struct io_tw_state ts = { .locked = true, };
mutex_lock(&ctx->uring_lock);
llist_for_each_entry_safe(req, tmp, node, io_task_work.node)
req->io_task_work.func(req, &ts);
if (WARN_ON_ONCE(!ts.locked))
return;
io_submit_flush_completions(ctx);
mutex_unlock(&ctx->uring_lock);
}
static int io_alloc_hash_table(struct io_hash_table *table, unsigned bits)
{
unsigned hash_buckets = 1U << bits;
size_t hash_size = hash_buckets * sizeof(table->hbs[0]);
table->hbs = kmalloc(hash_size, GFP_KERNEL);
if (!table->hbs)
return -ENOMEM;
table->hash_bits = bits;
init_hash_table(table, hash_buckets);
return 0;
}
static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
{
struct io_ring_ctx *ctx;
int hash_bits;
ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
if (!ctx)
return NULL;
xa_init(&ctx->io_bl_xa);
/*
* Use 5 bits less than the max cq entries, that should give us around
* 32 entries per hash list if totally full and uniformly spread, but
* don't keep too many buckets to not overconsume memory.
*/
hash_bits = ilog2(p->cq_entries) - 5;
hash_bits = clamp(hash_bits, 1, 8);
if (io_alloc_hash_table(&ctx->cancel_table, hash_bits))
goto err;
if (io_alloc_hash_table(&ctx->cancel_table_locked, hash_bits))
goto err;
if (percpu_ref_init(&ctx->refs, io_ring_ctx_ref_free,
0, GFP_KERNEL))
goto err;
ctx->flags = p->flags;
init_waitqueue_head(&ctx->sqo_sq_wait);
INIT_LIST_HEAD(&ctx->sqd_list);
INIT_LIST_HEAD(&ctx->cq_overflow_list);
INIT_LIST_HEAD(&ctx->io_buffers_cache);
io_alloc_cache_init(&ctx->rsrc_node_cache, IO_NODE_ALLOC_CACHE_MAX,
sizeof(struct io_rsrc_node));
io_alloc_cache_init(&ctx->apoll_cache, IO_ALLOC_CACHE_MAX,
sizeof(struct async_poll));
io_alloc_cache_init(&ctx->netmsg_cache, IO_ALLOC_CACHE_MAX,
sizeof(struct io_async_msghdr));
init_completion(&ctx->ref_comp);
xa_init_flags(&ctx->personalities, XA_FLAGS_ALLOC1);
mutex_init(&ctx->uring_lock);
init_waitqueue_head(&ctx->cq_wait);
init_waitqueue_head(&ctx->poll_wq);
init_waitqueue_head(&ctx->rsrc_quiesce_wq);
spin_lock_init(&ctx->completion_lock);
spin_lock_init(&ctx->timeout_lock);
INIT_WQ_LIST(&ctx->iopoll_list);
INIT_LIST_HEAD(&ctx->io_buffers_pages);
INIT_LIST_HEAD(&ctx->io_buffers_comp);
INIT_LIST_HEAD(&ctx->defer_list);
INIT_LIST_HEAD(&ctx->timeout_list);
INIT_LIST_HEAD(&ctx->ltimeout_list);
INIT_LIST_HEAD(&ctx->rsrc_ref_list);
init_llist_head(&ctx->work_llist);
INIT_LIST_HEAD(&ctx->tctx_list);
ctx->submit_state.free_list.next = NULL;
INIT_WQ_LIST(&ctx->locked_free_list);
INIT_DELAYED_WORK(&ctx->fallback_work, io_fallback_req_func);
INIT_WQ_LIST(&ctx->submit_state.compl_reqs);
return ctx;
err:
kfree(ctx->cancel_table.hbs);
kfree(ctx->cancel_table_locked.hbs);
kfree(ctx->io_bl);
xa_destroy(&ctx->io_bl_xa);
kfree(ctx);
return NULL;
}
static void io_account_cq_overflow(struct io_ring_ctx *ctx)
{
struct io_rings *r = ctx->rings;
WRITE_ONCE(r->cq_overflow, READ_ONCE(r->cq_overflow) + 1);
ctx->cq_extra--;
}
static bool req_need_defer(struct io_kiocb *req, u32 seq)
{
if (unlikely(req->flags & REQ_F_IO_DRAIN)) {
struct io_ring_ctx *ctx = req->ctx;
return seq + READ_ONCE(ctx->cq_extra) != ctx->cached_cq_tail;
}
return false;
}
static void io_clean_op(struct io_kiocb *req)
{
if (req->flags & REQ_F_BUFFER_SELECTED) {
spin_lock(&req->ctx->completion_lock);
io_put_kbuf_comp(req);
spin_unlock(&req->ctx->completion_lock);
}
if (req->flags & REQ_F_NEED_CLEANUP) {
const struct io_cold_def *def = &io_cold_defs[req->opcode];
if (def->cleanup)
def->cleanup(req);
}
if ((req->flags & REQ_F_POLLED) && req->apoll) {
kfree(req->apoll->double_poll);
kfree(req->apoll);
req->apoll = NULL;
}
if (req->flags & REQ_F_INFLIGHT) {
struct io_uring_task *tctx = req->task->io_uring;
atomic_dec(&tctx->inflight_tracked);
}
if (req->flags & REQ_F_CREDS)
put_cred(req->creds);
if (req->flags & REQ_F_ASYNC_DATA) {
kfree(req->async_data);
req->async_data = NULL;
}
req->flags &= ~IO_REQ_CLEAN_FLAGS;
}
static inline void io_req_track_inflight(struct io_kiocb *req)
{
if (!(req->flags & REQ_F_INFLIGHT)) {
req->flags |= REQ_F_INFLIGHT;
atomic_inc(&req->task->io_uring->inflight_tracked);
}
}
static struct io_kiocb *__io_prep_linked_timeout(struct io_kiocb *req)
{
if (WARN_ON_ONCE(!req->link))
return NULL;
req->flags &= ~REQ_F_ARM_LTIMEOUT;
req->flags |= REQ_F_LINK_TIMEOUT;
/* linked timeouts should have two refs once prep'ed */
io_req_set_refcount(req);
__io_req_set_refcount(req->link, 2);
return req->link;
}
static inline struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req)
{
if (likely(!(req->flags & REQ_F_ARM_LTIMEOUT)))
return NULL;
return __io_prep_linked_timeout(req);
}
static noinline void __io_arm_ltimeout(struct io_kiocb *req)
{
io_queue_linked_timeout(__io_prep_linked_timeout(req));
}
static inline void io_arm_ltimeout(struct io_kiocb *req)
{
if (unlikely(req->flags & REQ_F_ARM_LTIMEOUT))
__io_arm_ltimeout(req);
}
static void io_prep_async_work(struct io_kiocb *req)
{
const struct io_issue_def *def = &io_issue_defs[req->opcode];
struct io_ring_ctx *ctx = req->ctx;
if (!(req->flags & REQ_F_CREDS)) {
req->flags |= REQ_F_CREDS;
req->creds = get_current_cred();
}
req->work.list.next = NULL;
req->work.flags = 0;
req->work.cancel_seq = atomic_read(&ctx->cancel_seq);
if (req->flags & REQ_F_FORCE_ASYNC)
req->work.flags |= IO_WQ_WORK_CONCURRENT;
if (req->file && !(req->flags & REQ_F_FIXED_FILE))
req->flags |= io_file_get_flags(req->file);
if (req->file && (req->flags & REQ_F_ISREG)) {
bool should_hash = def->hash_reg_file;
/* don't serialize this request if the fs doesn't need it */
if (should_hash && (req->file->f_flags & O_DIRECT) &&
(req->file->f_mode & FMODE_DIO_PARALLEL_WRITE))
should_hash = false;
if (should_hash || (ctx->flags & IORING_SETUP_IOPOLL))
io_wq_hash_work(&req->work, file_inode(req->file));
} else if (!req->file || !S_ISBLK(file_inode(req->file)->i_mode)) {
if (def->unbound_nonreg_file)
req->work.flags |= IO_WQ_WORK_UNBOUND;
}
}
static void io_prep_async_link(struct io_kiocb *req)
{
struct io_kiocb *cur;
if (req->flags & REQ_F_LINK_TIMEOUT) {
struct io_ring_ctx *ctx = req->ctx;
spin_lock_irq(&ctx->timeout_lock);
io_for_each_link(cur, req)
io_prep_async_work(cur);
spin_unlock_irq(&ctx->timeout_lock);
} else {
io_for_each_link(cur, req)
io_prep_async_work(cur);
}
}
void io_queue_iowq(struct io_kiocb *req, struct io_tw_state *ts_dont_use)
{
struct io_kiocb *link = io_prep_linked_timeout(req);
struct io_uring_task *tctx = req->task->io_uring;
BUG_ON(!tctx);
BUG_ON(!tctx->io_wq);
/* init ->work of the whole link before punting */
io_prep_async_link(req);
/*
* Not expected to happen, but if we do have a bug where this _can_
* happen, catch it here and ensure the request is marked as
* canceled. That will make io-wq go through the usual work cancel
* procedure rather than attempt to run this request (or create a new
* worker for it).
*/
if (WARN_ON_ONCE(!same_thread_group(req->task, current)))
req->work.flags |= IO_WQ_WORK_CANCEL;
trace_io_uring_queue_async_work(req, io_wq_is_hashed(&req->work));
io_wq_enqueue(tctx->io_wq, &req->work);
if (link)
io_queue_linked_timeout(link);
}
static __cold void io_queue_deferred(struct io_ring_ctx *ctx)
{
while (!list_empty(&ctx->defer_list)) {
struct io_defer_entry *de = list_first_entry(&ctx->defer_list,
struct io_defer_entry, list);
if (req_need_defer(de->req, de->seq))
break;
list_del_init(&de->list);
io_req_task_queue(de->req);
kfree(de);
}
}
static void io_eventfd_ops(struct rcu_head *rcu)
{
struct io_ev_fd *ev_fd = container_of(rcu, struct io_ev_fd, rcu);
int ops = atomic_xchg(&ev_fd->ops, 0);
if (ops & BIT(IO_EVENTFD_OP_SIGNAL_BIT))
eventfd_signal_mask(ev_fd->cq_ev_fd, 1, EPOLL_URING_WAKE);
/* IO_EVENTFD_OP_FREE_BIT may not be set here depending on callback
* ordering in a race but if references are 0 we know we have to free
* it regardless.
*/
if (atomic_dec_and_test(&ev_fd->refs)) {
eventfd_ctx_put(ev_fd->cq_ev_fd);
kfree(ev_fd);
}
}
static void io_eventfd_signal(struct io_ring_ctx *ctx)
{
struct io_ev_fd *ev_fd = NULL;
rcu_read_lock();
/*
* rcu_dereference ctx->io_ev_fd once and use it for both for checking
* and eventfd_signal
*/
ev_fd = rcu_dereference(ctx->io_ev_fd);
/*
* Check again if ev_fd exists incase an io_eventfd_unregister call
* completed between the NULL check of ctx->io_ev_fd at the start of
* the function and rcu_read_lock.
*/
if (unlikely(!ev_fd))
goto out;
if (READ_ONCE(ctx->rings->cq_flags) & IORING_CQ_EVENTFD_DISABLED)
goto out;
if (ev_fd->eventfd_async && !io_wq_current_is_worker())
goto out;
if (likely(eventfd_signal_allowed())) {
eventfd_signal_mask(ev_fd->cq_ev_fd, 1, EPOLL_URING_WAKE);
} else {
atomic_inc(&ev_fd->refs);
if (!atomic_fetch_or(BIT(IO_EVENTFD_OP_SIGNAL_BIT), &ev_fd->ops))
call_rcu_hurry(&ev_fd->rcu, io_eventfd_ops);
else
atomic_dec(&ev_fd->refs);
}
out:
rcu_read_unlock();
}
static void io_eventfd_flush_signal(struct io_ring_ctx *ctx)
{
bool skip;
spin_lock(&ctx->completion_lock);
/*
* Eventfd should only get triggered when at least one event has been
* posted. Some applications rely on the eventfd notification count
* only changing IFF a new CQE has been added to the CQ ring. There's
* no depedency on 1:1 relationship between how many times this
* function is called (and hence the eventfd count) and number of CQEs
* posted to the CQ ring.
*/
skip = ctx->cached_cq_tail == ctx->evfd_last_cq_tail;
ctx->evfd_last_cq_tail = ctx->cached_cq_tail;
spin_unlock(&ctx->completion_lock);
if (skip)
return;
io_eventfd_signal(ctx);
}
void __io_commit_cqring_flush(struct io_ring_ctx *ctx)
{
if (ctx->poll_activated)
io_poll_wq_wake(ctx);
if (ctx->off_timeout_used)
io_flush_timeouts(ctx);
if (ctx->drain_active) {
spin_lock(&ctx->completion_lock);
io_queue_deferred(ctx);
spin_unlock(&ctx->completion_lock);
}
if (ctx->has_evfd)
io_eventfd_flush_signal(ctx);
}
static inline void __io_cq_lock(struct io_ring_ctx *ctx)
{
if (!ctx->lockless_cq)
spin_lock(&ctx->completion_lock);
}
static inline void io_cq_lock(struct io_ring_ctx *ctx)
__acquires(ctx->completion_lock)
{
spin_lock(&ctx->completion_lock);
}
static inline void __io_cq_unlock_post(struct io_ring_ctx *ctx)
{
io_commit_cqring(ctx);
if (!ctx->task_complete) {
if (!ctx->lockless_cq)
spin_unlock(&ctx->completion_lock);
/* IOPOLL rings only need to wake up if it's also SQPOLL */
if (!ctx->syscall_iopoll)
io_cqring_wake(ctx);
}
io_commit_cqring_flush(ctx);
}
static void io_cq_unlock_post(struct io_ring_ctx *ctx)
__releases(ctx->completion_lock)
{
io_commit_cqring(ctx);
spin_unlock(&ctx->completion_lock);
io_cqring_wake(ctx);
io_commit_cqring_flush(ctx);
}
/* Returns true if there are no backlogged entries after the flush */
static void io_cqring_overflow_kill(struct io_ring_ctx *ctx)
{
struct io_overflow_cqe *ocqe;
LIST_HEAD(list);
spin_lock(&ctx->completion_lock);
list_splice_init(&ctx->cq_overflow_list, &list);
clear_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq);
spin_unlock(&ctx->completion_lock);
while (!list_empty(&list)) {
ocqe = list_first_entry(&list, struct io_overflow_cqe, list);
list_del(&ocqe->list);
kfree(ocqe);
}
}
static void __io_cqring_overflow_flush(struct io_ring_ctx *ctx)
{
size_t cqe_size = sizeof(struct io_uring_cqe);
if (__io_cqring_events(ctx) == ctx->cq_entries)
return;
if (ctx->flags & IORING_SETUP_CQE32)
cqe_size <<= 1;
io_cq_lock(ctx);
while (!list_empty(&ctx->cq_overflow_list)) {
struct io_uring_cqe *cqe;
struct io_overflow_cqe *ocqe;
if (!io_get_cqe_overflow(ctx, &cqe, true))
break;
ocqe = list_first_entry(&ctx->cq_overflow_list,
struct io_overflow_cqe, list);
memcpy(cqe, &ocqe->cqe, cqe_size);
list_del(&ocqe->list);
kfree(ocqe);
}
if (list_empty(&ctx->cq_overflow_list)) {
clear_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq);
atomic_andnot(IORING_SQ_CQ_OVERFLOW, &ctx->rings->sq_flags);
}
io_cq_unlock_post(ctx);
}
static void io_cqring_do_overflow_flush(struct io_ring_ctx *ctx)
{
/* iopoll syncs against uring_lock, not completion_lock */
if (ctx->flags & IORING_SETUP_IOPOLL)
mutex_lock(&ctx->uring_lock);
__io_cqring_overflow_flush(ctx);
if (ctx->flags & IORING_SETUP_IOPOLL)
mutex_unlock(&ctx->uring_lock);
}
static void io_cqring_overflow_flush(struct io_ring_ctx *ctx)
{
if (test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq))
io_cqring_do_overflow_flush(ctx);
}
/* can be called by any task */
static void io_put_task_remote(struct task_struct *task)
{
struct io_uring_task *tctx = task->io_uring;
percpu_counter_sub(&tctx->inflight, 1);
if (unlikely(atomic_read(&tctx->in_cancel)))
wake_up(&tctx->wait);
put_task_struct(task);
}
/* used by a task to put its own references */
static void io_put_task_local(struct task_struct *task)
{
task->io_uring->cached_refs++;
}
/* must to be called somewhat shortly after putting a request */
static inline void io_put_task(struct task_struct *task)
{
if (likely(task == current))
io_put_task_local(task);
else
io_put_task_remote(task);
}
void io_task_refs_refill(struct io_uring_task *tctx)
{
unsigned int refill = -tctx->cached_refs + IO_TCTX_REFS_CACHE_NR;
percpu_counter_add(&tctx->inflight, refill);
refcount_add(refill, ¤t->usage);
tctx->cached_refs += refill;
}
static __cold void io_uring_drop_tctx_refs(struct task_struct *task)
{
struct io_uring_task *tctx = task->io_uring;
unsigned int refs = tctx->cached_refs;
if (refs) {
tctx->cached_refs = 0;
percpu_counter_sub(&tctx->inflight, refs);
put_task_struct_many(task, refs);
}
}
static bool io_cqring_event_overflow(struct io_ring_ctx *ctx, u64 user_data,
s32 res, u32 cflags, u64 extra1, u64 extra2)
{
struct io_overflow_cqe *ocqe;
size_t ocq_size = sizeof(struct io_overflow_cqe);
bool is_cqe32 = (ctx->flags & IORING_SETUP_CQE32);
lockdep_assert_held(&ctx->completion_lock);
if (is_cqe32)
ocq_size += sizeof(struct io_uring_cqe);
ocqe = kmalloc(ocq_size, GFP_ATOMIC | __GFP_ACCOUNT);
trace_io_uring_cqe_overflow(ctx, user_data, res, cflags, ocqe);
if (!ocqe) {
/*
* If we're in ring overflow flush mode, or in task cancel mode,
* or cannot allocate an overflow entry, then we need to drop it
* on the floor.
*/
io_account_cq_overflow(ctx);
set_bit(IO_CHECK_CQ_DROPPED_BIT, &ctx->check_cq);
return false;
}
if (list_empty(&ctx->cq_overflow_list)) {
set_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq);
atomic_or(IORING_SQ_CQ_OVERFLOW, &ctx->rings->sq_flags);
}
ocqe->cqe.user_data = user_data;
ocqe->cqe.res = res;
ocqe->cqe.flags = cflags;
if (is_cqe32) {
ocqe->cqe.big_cqe[0] = extra1;
ocqe->cqe.big_cqe[1] = extra2;
}
list_add_tail(&ocqe->list, &ctx->cq_overflow_list);
return true;
}
void io_req_cqe_overflow(struct io_kiocb *req)
{
io_cqring_event_overflow(req->ctx, req->cqe.user_data,
req->cqe.res, req->cqe.flags,
req->big_cqe.extra1, req->big_cqe.extra2);
memset(&req->big_cqe, 0, sizeof(req->big_cqe));
}
/*
* writes to the cq entry need to come after reading head; the
* control dependency is enough as we're using WRITE_ONCE to
* fill the cq entry
*/
bool io_cqe_cache_refill(struct io_ring_ctx *ctx, bool overflow)
{
struct io_rings *rings = ctx->rings;
unsigned int off = ctx->cached_cq_tail & (ctx->cq_entries - 1);
unsigned int free, queued, len;
/*
* Posting into the CQ when there are pending overflowed CQEs may break
* ordering guarantees, which will affect links, F_MORE users and more.
* Force overflow the completion.
*/
if (!overflow && (ctx->check_cq & BIT(IO_CHECK_CQ_OVERFLOW_BIT)))
return false;
/* userspace may cheat modifying the tail, be safe and do min */
queued = min(__io_cqring_events(ctx), ctx->cq_entries);
free = ctx->cq_entries - queued;
/* we need a contiguous range, limit based on the current array offset */
len = min(free, ctx->cq_entries - off);
if (!len)
return false;
if (ctx->flags & IORING_SETUP_CQE32) {
off <<= 1;
len <<= 1;
}
ctx->cqe_cached = &rings->cqes[off];
ctx->cqe_sentinel = ctx->cqe_cached + len;
return true;
}
static bool io_fill_cqe_aux(struct io_ring_ctx *ctx, u64 user_data, s32 res,
u32 cflags)
{
struct io_uring_cqe *cqe;
ctx->cq_extra++;
/*
* If we can't get a cq entry, userspace overflowed the
* submission (by quite a lot). Increment the overflow count in
* the ring.
*/
if (likely(io_get_cqe(ctx, &cqe))) {
trace_io_uring_complete(ctx, NULL, user_data, res, cflags, 0, 0);
WRITE_ONCE(cqe->user_data, user_data);
WRITE_ONCE(cqe->res, res);
WRITE_ONCE(cqe->flags, cflags);
if (ctx->flags & IORING_SETUP_CQE32) {
WRITE_ONCE(cqe->big_cqe[0], 0);
WRITE_ONCE(cqe->big_cqe[1], 0);
}
return true;
}
return false;
}
static void __io_flush_post_cqes(struct io_ring_ctx *ctx)
__must_hold(&ctx->uring_lock)
{
struct io_submit_state *state = &ctx->submit_state;
unsigned int i;
lockdep_assert_held(&ctx->uring_lock);
for (i = 0; i < state->cqes_count; i++) {
struct io_uring_cqe *cqe = &ctx->completion_cqes[i];
if (!io_fill_cqe_aux(ctx, cqe->user_data, cqe->res, cqe->flags)) {
if (ctx->lockless_cq) {
spin_lock(&ctx->completion_lock);
io_cqring_event_overflow(ctx, cqe->user_data,
cqe->res, cqe->flags, 0, 0);
spin_unlock(&ctx->completion_lock);
} else {
io_cqring_event_overflow(ctx, cqe->user_data,
cqe->res, cqe->flags, 0, 0);
}
}
}
state->cqes_count = 0;
}
static bool __io_post_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags,
bool allow_overflow)
{
bool filled;
io_cq_lock(ctx);
filled = io_fill_cqe_aux(ctx, user_data, res, cflags);
if (!filled && allow_overflow)
filled = io_cqring_event_overflow(ctx, user_data, res, cflags, 0, 0);
io_cq_unlock_post(ctx);
return filled;
}
bool io_post_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags)
{
return __io_post_aux_cqe(ctx, user_data, res, cflags, true);
}
/*
* A helper for multishot requests posting additional CQEs.
* Should only be used from a task_work including IO_URING_F_MULTISHOT.
*/
bool io_fill_cqe_req_aux(struct io_kiocb *req, bool defer, s32 res, u32 cflags)
{
struct io_ring_ctx *ctx = req->ctx;
u64 user_data = req->cqe.user_data;
struct io_uring_cqe *cqe;
if (!defer)
return __io_post_aux_cqe(ctx, user_data, res, cflags, false);
lockdep_assert_held(&ctx->uring_lock);
if (ctx->submit_state.cqes_count == ARRAY_SIZE(ctx->completion_cqes)) {
__io_cq_lock(ctx);
__io_flush_post_cqes(ctx);
/* no need to flush - flush is deferred */
__io_cq_unlock_post(ctx);
}
/* For defered completions this is not as strict as it is otherwise,
* however it's main job is to prevent unbounded posted completions,
* and in that it works just as well.
*/
if (test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq))
return false;
cqe = &ctx->completion_cqes[ctx->submit_state.cqes_count++];
cqe->user_data = user_data;
cqe->res = res;
cqe->flags = cflags;
return true;
}
static void __io_req_complete_post(struct io_kiocb *req, unsigned issue_flags)
{
struct io_ring_ctx *ctx = req->ctx;
struct io_rsrc_node *rsrc_node = NULL;
io_cq_lock(ctx);
if (!(req->flags & REQ_F_CQE_SKIP)) {
if (!io_fill_cqe_req(ctx, req))
io_req_cqe_overflow(req);
}
/*
* If we're the last reference to this request, add to our locked
* free_list cache.
*/
if (req_ref_put_and_test(req)) {
if (req->flags & IO_REQ_LINK_FLAGS) {
if (req->flags & IO_DISARM_MASK)
io_disarm_next(req);
if (req->link) {
io_req_task_queue(req->link);
req->link = NULL;
}
}
io_put_kbuf_comp(req);
if (unlikely(req->flags & IO_REQ_CLEAN_FLAGS))
io_clean_op(req);
io_put_file(req);
rsrc_node = req->rsrc_node;
/*
* Selected buffer deallocation in io_clean_op() assumes that
* we don't hold ->completion_lock. Clean them here to avoid
* deadlocks.
*/
io_put_task_remote(req->task);
wq_list_add_head(&req->comp_list, &ctx->locked_free_list);
ctx->locked_free_nr++;
}
io_cq_unlock_post(ctx);
if (rsrc_node) {
io_ring_submit_lock(ctx, issue_flags);
io_put_rsrc_node(ctx, rsrc_node);
io_ring_submit_unlock(ctx, issue_flags);
}
}
void io_req_complete_post(struct io_kiocb *req, unsigned issue_flags)
{
if (req->ctx->task_complete && req->ctx->submitter_task != current) {
req->io_task_work.func = io_req_task_complete;
io_req_task_work_add(req);
} else if (!(issue_flags & IO_URING_F_UNLOCKED) ||
!(req->ctx->flags & IORING_SETUP_IOPOLL)) {
__io_req_complete_post(req, issue_flags);
} else {
struct io_ring_ctx *ctx = req->ctx;
mutex_lock(&ctx->uring_lock);
__io_req_complete_post(req, issue_flags & ~IO_URING_F_UNLOCKED);
mutex_unlock(&ctx->uring_lock);
}
}
void io_req_defer_failed(struct io_kiocb *req, s32 res)
__must_hold(&ctx->uring_lock)
{
const struct io_cold_def *def = &io_cold_defs[req->opcode];
lockdep_assert_held(&req->ctx->uring_lock);
req_set_fail(req);
io_req_set_res(req, res, io_put_kbuf(req, IO_URING_F_UNLOCKED));
if (def->fail)
def->fail(req);
io_req_complete_defer(req);
}
/*
* Don't initialise the fields below on every allocation, but do that in
* advance and keep them valid across allocations.
*/
static void io_preinit_req(struct io_kiocb *req, struct io_ring_ctx *ctx)
{
req->ctx = ctx;
req->link = NULL;
req->async_data = NULL;
/* not necessary, but safer to zero */
memset(&req->cqe, 0, sizeof(req->cqe));
memset(&req->big_cqe, 0, sizeof(req->big_cqe));
}
static void io_flush_cached_locked_reqs(struct io_ring_ctx *ctx,
struct io_submit_state *state)
{
spin_lock(&ctx->completion_lock);
wq_list_splice(&ctx->locked_free_list, &state->free_list);
ctx->locked_free_nr = 0;
spin_unlock(&ctx->completion_lock);
}
/*
* A request might get retired back into the request caches even before opcode
* handlers and io_issue_sqe() are done with it, e.g. inline completion path.
* Because of that, io_alloc_req() should be called only under ->uring_lock
* and with extra caution to not get a request that is still worked on.
*/
__cold bool __io_alloc_req_refill(struct io_ring_ctx *ctx)
__must_hold(&ctx->uring_lock)
{
gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;
void *reqs[IO_REQ_ALLOC_BATCH];
int ret, i;
/*
* If we have more than a batch's worth of requests in our IRQ side
* locked cache, grab the lock and move them over to our submission
* side cache.
*/
if (data_race(ctx->locked_free_nr) > IO_COMPL_BATCH) {
io_flush_cached_locked_reqs(ctx, &ctx->submit_state);
if (!io_req_cache_empty(ctx))
return true;
}
ret = kmem_cache_alloc_bulk(req_cachep, gfp, ARRAY_SIZE(reqs), reqs);
/*
* Bulk alloc is all-or-nothing. If we fail to get a batch,
* retry single alloc to be on the safe side.
*/
if (unlikely(ret <= 0)) {
reqs[0] = kmem_cache_alloc(req_cachep, gfp);
if (!reqs[0])
return false;
ret = 1;
}
percpu_ref_get_many(&ctx->refs, ret);
for (i = 0; i < ret; i++) {
struct io_kiocb *req = reqs[i];
io_preinit_req(req, ctx);
io_req_add_to_cache(req, ctx);
}
return true;
}
__cold void io_free_req(struct io_kiocb *req)
{
/* refs were already put, restore them for io_req_task_complete() */
req->flags &= ~REQ_F_REFCOUNT;
/* we only want to free it, don't post CQEs */
req->flags |= REQ_F_CQE_SKIP;
req->io_task_work.func = io_req_task_complete;
io_req_task_work_add(req);
}
static void __io_req_find_next_prep(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
spin_lock(&ctx->completion_lock);
io_disarm_next(req);
spin_unlock(&ctx->completion_lock);
}
static inline struct io_kiocb *io_req_find_next(struct io_kiocb *req)
{
struct io_kiocb *nxt;
/*
* If LINK is set, we have dependent requests in this chain. If we
* didn't fail this request, queue the first one up, moving any other
* dependencies to the next request. In case of failure, fail the rest
* of the chain.
*/
if (unlikely(req->flags & IO_DISARM_MASK))
__io_req_find_next_prep(req);
nxt = req->link;
req->link = NULL;
return nxt;
}
static void ctx_flush_and_put(struct io_ring_ctx *ctx, struct io_tw_state *ts)
{
if (!ctx)
return;
if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
atomic_andnot(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);
if (ts->locked) {
io_submit_flush_completions(ctx);
mutex_unlock(&ctx->uring_lock);
ts->locked = false;
}
percpu_ref_put(&ctx->refs);
}
static unsigned int handle_tw_list(struct llist_node *node,
struct io_ring_ctx **ctx,
struct io_tw_state *ts,
struct llist_node *last)
{
unsigned int count = 0;
while (node && node != last) {
struct llist_node *next = node->next;
struct io_kiocb *req = container_of(node, struct io_kiocb,
io_task_work.node);
prefetch(container_of(next, struct io_kiocb, io_task_work.node));
if (req->ctx != *ctx) {
ctx_flush_and_put(*ctx, ts);
*ctx = req->ctx;
/* if not contended, grab and improve batching */
ts->locked = mutex_trylock(&(*ctx)->uring_lock);
percpu_ref_get(&(*ctx)->refs);
}
INDIRECT_CALL_2(req->io_task_work.func,
io_poll_task_func, io_req_rw_complete,
req, ts);
node = next;
count++;
if (unlikely(need_resched())) {
ctx_flush_and_put(*ctx, ts);
*ctx = NULL;
cond_resched();
}
}
return count;
}
/**
* io_llist_xchg - swap all entries in a lock-less list
* @head: the head of lock-less list to delete all entries
* @new: new entry as the head of the list
*
* If list is empty, return NULL, otherwise, return the pointer to the first entry.
* The order of entries returned is from the newest to the oldest added one.
*/
static inline struct llist_node *io_llist_xchg(struct llist_head *head,
struct llist_node *new)
{
return xchg(&head->first, new);
}
/**
* io_llist_cmpxchg - possibly swap all entries in a lock-less list
* @head: the head of lock-less list to delete all entries
* @old: expected old value of the first entry of the list
* @new: new entry as the head of the list
*
* perform a cmpxchg on the first entry of the list.
*/
static inline struct llist_node *io_llist_cmpxchg(struct llist_head *head,
struct llist_node *old,
struct llist_node *new)
{
return cmpxchg(&head->first, old, new);
}
static __cold void io_fallback_tw(struct io_uring_task *tctx, bool sync)
{
struct llist_node *node = llist_del_all(&tctx->task_list);
struct io_ring_ctx *last_ctx = NULL;
struct io_kiocb *req;
while (node) {
req = container_of(node, struct io_kiocb, io_task_work.node);
node = node->next;
if (sync && last_ctx != req->ctx) {
if (last_ctx) {
flush_delayed_work(&last_ctx->fallback_work);
percpu_ref_put(&last_ctx->refs);
}
last_ctx = req->ctx;
percpu_ref_get(&last_ctx->refs);
}
if (llist_add(&req->io_task_work.node,
&req->ctx->fallback_llist))
schedule_delayed_work(&req->ctx->fallback_work, 1);
}
if (last_ctx) {
flush_delayed_work(&last_ctx->fallback_work);
percpu_ref_put(&last_ctx->refs);
}
}
void tctx_task_work(struct callback_head *cb)
{
struct io_tw_state ts = {};
struct io_ring_ctx *ctx = NULL;
struct io_uring_task *tctx = container_of(cb, struct io_uring_task,
task_work);
struct llist_node fake = {};
struct llist_node *node;
unsigned int loops = 0;
unsigned int count = 0;
if (unlikely(current->flags & PF_EXITING)) {
io_fallback_tw(tctx, true);
return;
}
do {
loops++;
node = io_llist_xchg(&tctx->task_list, &fake);
count += handle_tw_list(node, &ctx, &ts, &fake);
/* skip expensive cmpxchg if there are items in the list */
if (READ_ONCE(tctx->task_list.first) != &fake)
continue;
if (ts.locked && !wq_list_empty(&ctx->submit_state.compl_reqs)) {
io_submit_flush_completions(ctx);
if (READ_ONCE(tctx->task_list.first) != &fake)
continue;
}
node = io_llist_cmpxchg(&tctx->task_list, &fake, NULL);
} while (node != &fake);
ctx_flush_and_put(ctx, &ts);
/* relaxed read is enough as only the task itself sets ->in_cancel */
if (unlikely(atomic_read(&tctx->in_cancel)))
io_uring_drop_tctx_refs(current);
trace_io_uring_task_work_run(tctx, count, loops);
}
static inline void io_req_local_work_add(struct io_kiocb *req, unsigned flags)
{
struct io_ring_ctx *ctx = req->ctx;
unsigned nr_wait, nr_tw, nr_tw_prev;
struct llist_node *first;
if (req->flags & (REQ_F_LINK | REQ_F_HARDLINK))
flags &= ~IOU_F_TWQ_LAZY_WAKE;
first = READ_ONCE(ctx->work_llist.first);
do {
nr_tw_prev = 0;
if (first) {
struct io_kiocb *first_req = container_of(first,
struct io_kiocb,
io_task_work.node);
/*
* Might be executed at any moment, rely on
* SLAB_TYPESAFE_BY_RCU to keep it alive.
*/
nr_tw_prev = READ_ONCE(first_req->nr_tw);
}
nr_tw = nr_tw_prev + 1;
/* Large enough to fail the nr_wait comparison below */
if (!(flags & IOU_F_TWQ_LAZY_WAKE))
nr_tw = -1U;
req->nr_tw = nr_tw;
req->io_task_work.node.next = first;
} while (!try_cmpxchg(&ctx->work_llist.first, &first,
&req->io_task_work.node));
if (!first) {
if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
atomic_or(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);
if (ctx->has_evfd)
io_eventfd_signal(ctx);
}
nr_wait = atomic_read(&ctx->cq_wait_nr);
/* no one is waiting */
if (!nr_wait)
return;
/* either not enough or the previous add has already woken it up */
if (nr_wait > nr_tw || nr_tw_prev >= nr_wait)
return;
/* pairs with set_current_state() in io_cqring_wait() */
smp_mb__after_atomic();
wake_up_state(ctx->submitter_task, TASK_INTERRUPTIBLE);
}
static void io_req_normal_work_add(struct io_kiocb *req)
{
struct io_uring_task *tctx = req->task->io_uring;
struct io_ring_ctx *ctx = req->ctx;
/* task_work already pending, we're done */
if (!llist_add(&req->io_task_work.node, &tctx->task_list))
return;
if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
atomic_or(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);
if (likely(!task_work_add(req->task, &tctx->task_work, ctx->notify_method)))
return;
io_fallback_tw(tctx, false);
}
void __io_req_task_work_add(struct io_kiocb *req, unsigned flags)
{
if (req->ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
rcu_read_lock();
io_req_local_work_add(req, flags);
rcu_read_unlock();
} else {
io_req_normal_work_add(req);
}
}
static void __cold io_move_task_work_from_local(struct io_ring_ctx *ctx)
{
struct llist_node *node;
node = llist_del_all(&ctx->work_llist);
while (node) {
struct io_kiocb *req = container_of(node, struct io_kiocb,
io_task_work.node);
node = node->next;
io_req_normal_work_add(req);
}
}
static int __io_run_local_work(struct io_ring_ctx *ctx, struct io_tw_state *ts)
{
struct llist_node *node;
unsigned int loops = 0;
int ret = 0;
if (WARN_ON_ONCE(ctx->submitter_task != current))
return -EEXIST;
if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
atomic_andnot(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);
again:
/*
* llists are in reverse order, flip it back the right way before
* running the pending items.
*/
node = llist_reverse_order(io_llist_xchg(&ctx->work_llist, NULL));
while (node) {
struct llist_node *next = node->next;
struct io_kiocb *req = container_of(node, struct io_kiocb,
io_task_work.node);
prefetch(container_of(next, struct io_kiocb, io_task_work.node));
INDIRECT_CALL_2(req->io_task_work.func,
io_poll_task_func, io_req_rw_complete,
req, ts);
ret++;
node = next;
}
loops++;
if (!llist_empty(&ctx->work_llist))
goto again;
if (ts->locked) {
io_submit_flush_completions(ctx);
if (!llist_empty(&ctx->work_llist))
goto again;
}
trace_io_uring_local_work_run(ctx, ret, loops);
return ret;
}
static inline int io_run_local_work_locked(struct io_ring_ctx *ctx)
{
struct io_tw_state ts = { .locked = true, };
int ret;
if (llist_empty(&ctx->work_llist))
return 0;
ret = __io_run_local_work(ctx, &ts);
/* shouldn't happen! */
if (WARN_ON_ONCE(!ts.locked))
mutex_lock(&ctx->uring_lock);
return ret;
}
static int io_run_local_work(struct io_ring_ctx *ctx)
{
struct io_tw_state ts = {};
int ret;
ts.locked = mutex_trylock(&ctx->uring_lock);
ret = __io_run_local_work(ctx, &ts);
if (ts.locked)
mutex_unlock(&ctx->uring_lock);
return ret;
}
static void io_req_task_cancel(struct io_kiocb *req, struct io_tw_state *ts)
{
io_tw_lock(req->ctx, ts);
io_req_defer_failed(req, req->cqe.res);
}
void io_req_task_submit(struct io_kiocb *req, struct io_tw_state *ts)
{
io_tw_lock(req->ctx, ts);
/* req->task == current here, checking PF_EXITING is safe */
if (unlikely(req->task->flags & PF_EXITING))
io_req_defer_failed(req, -EFAULT);
else if (req->flags & REQ_F_FORCE_ASYNC)
io_queue_iowq(req, ts);
else
io_queue_sqe(req);
}
void io_req_task_queue_fail(struct io_kiocb *req, int ret)
{
io_req_set_res(req, ret, 0);
req->io_task_work.func = io_req_task_cancel;
io_req_task_work_add(req);
}
void io_req_task_queue(struct io_kiocb *req)
{
req->io_task_work.func = io_req_task_submit;
io_req_task_work_add(req);
}
void io_queue_next(struct io_kiocb *req)
{
struct io_kiocb *nxt = io_req_find_next(req);
if (nxt)
io_req_task_queue(nxt);
}
static void io_free_batch_list(struct io_ring_ctx *ctx,
struct io_wq_work_node *node)
__must_hold(&ctx->uring_lock)
{
do {
struct io_kiocb *req = container_of(node, struct io_kiocb,
comp_list);
if (unlikely(req->flags & IO_REQ_CLEAN_SLOW_FLAGS)) {
if (req->flags & REQ_F_REFCOUNT) {
node = req->comp_list.next;
if (!req_ref_put_and_test(req))
continue;
}
if ((req->flags & REQ_F_POLLED) && req->apoll) {
struct async_poll *apoll = req->apoll;
if (apoll->double_poll)
kfree(apoll->double_poll);
if (!io_alloc_cache_put(&ctx->apoll_cache, &apoll->cache))
kfree(apoll);
req->flags &= ~REQ_F_POLLED;
}
if (req->flags & IO_REQ_LINK_FLAGS)
io_queue_next(req);
if (unlikely(req->flags & IO_REQ_CLEAN_FLAGS))
io_clean_op(req);
}
io_put_file(req);
io_req_put_rsrc_locked(req, ctx);
io_put_task(req->task);
node = req->comp_list.next;
io_req_add_to_cache(req, ctx);
} while (node);
}
void __io_submit_flush_completions(struct io_ring_ctx *ctx)
__must_hold(&ctx->uring_lock)
{
struct io_submit_state *state = &ctx->submit_state;
struct io_wq_work_node *node;
__io_cq_lock(ctx);
/* must come first to preserve CQE ordering in failure cases */
if (state->cqes_count)
__io_flush_post_cqes(ctx);
__wq_list_for_each(node, &state->compl_reqs) {
struct io_kiocb *req = container_of(node, struct io_kiocb,
comp_list);
if (!(req->flags & REQ_F_CQE_SKIP) &&
unlikely(!io_fill_cqe_req(ctx, req))) {
if (ctx->lockless_cq) {
spin_lock(&ctx->completion_lock);
io_req_cqe_overflow(req);
spin_unlock(&ctx->completion_lock);
} else {
io_req_cqe_overflow(req);
}
}
}
__io_cq_unlock_post(ctx);
if (!wq_list_empty(&ctx->submit_state.compl_reqs)) {
io_free_batch_list(ctx, state->compl_reqs.first);
INIT_WQ_LIST(&state->compl_reqs);
}
}
static unsigned io_cqring_events(struct io_ring_ctx *ctx)
{
/* See comment at the top of this file */
smp_rmb();
return __io_cqring_events(ctx);
}
/*
* We can't just wait for polled events to come to us, we have to actively
* find and complete them.
*/
static __cold void io_iopoll_try_reap_events(struct io_ring_ctx *ctx)
{
if (!(ctx->flags & IORING_SETUP_IOPOLL))
return;
mutex_lock(&ctx->uring_lock);
while (!wq_list_empty(&ctx->iopoll_list)) {
/* let it sleep and repeat later if can't complete a request */
if (io_do_iopoll(ctx, true) == 0)
break;
/*
* Ensure we allow local-to-the-cpu processing to take place,
* in this case we need to ensure that we reap all events.
* Also let task_work, etc. to progress by releasing the mutex
*/
if (need_resched()) {
mutex_unlock(&ctx->uring_lock);
cond_resched();
mutex_lock(&ctx->uring_lock);
}
}
mutex_unlock(&ctx->uring_lock);
}
static int io_iopoll_check(struct io_ring_ctx *ctx, long min)
{
unsigned int nr_events = 0;
unsigned long check_cq;
if (!io_allowed_run_tw(ctx))
return -EEXIST;
check_cq = READ_ONCE(ctx->check_cq);
if (unlikely(check_cq)) {
if (check_cq & BIT(IO_CHECK_CQ_OVERFLOW_BIT))
__io_cqring_overflow_flush(ctx);
/*
* Similarly do not spin if we have not informed the user of any
* dropped CQE.
*/
if (check_cq & BIT(IO_CHECK_CQ_DROPPED_BIT))
return -EBADR;
}
/*
* Don't enter poll loop if we already have events pending.
* If we do, we can potentially be spinning for commands that
* already triggered a CQE (eg in error).
*/
if (io_cqring_events(ctx))
return 0;
do {
int ret = 0;
/*
* If a submit got punted to a workqueue, we can have the
* application entering polling for a command before it gets
* issued. That app will hold the uring_lock for the duration
* of the poll right here, so we need to take a breather every
* now and then to ensure that the issue has a chance to add
* the poll to the issued list. Otherwise we can spin here
* forever, while the workqueue is stuck trying to acquire the
* very same mutex.
*/
if (wq_list_empty(&ctx->iopoll_list) ||
io_task_work_pending(ctx)) {
u32 tail = ctx->cached_cq_tail;
(void) io_run_local_work_locked(ctx);
if (task_work_pending(current) ||
wq_list_empty(&ctx->iopoll_list)) {
mutex_unlock(&ctx->uring_lock);
io_run_task_work();
mutex_lock(&ctx->uring_lock);
}
/* some requests don't go through iopoll_list */
if (tail != ctx->cached_cq_tail ||
wq_list_empty(&ctx->iopoll_list))
break;
}
ret = io_do_iopoll(ctx, !min);
if (unlikely(ret < 0))
return ret;
if (task_sigpending(current))
return -EINTR;
if (need_resched())
break;
nr_events += ret;
} while (nr_events < min);
return 0;
}
void io_req_task_complete(struct io_kiocb *req, struct io_tw_state *ts)
{
if (ts->locked)
io_req_complete_defer(req);
else
io_req_complete_post(req, IO_URING_F_UNLOCKED);
}
/*
* After the iocb has been issued, it's safe to be found on the poll list.
* Adding the kiocb to the list AFTER submission ensures that we don't
* find it from a io_do_iopoll() thread before the issuer is done
* accessing the kiocb cookie.
*/
static void io_iopoll_req_issued(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_ring_ctx *ctx = req->ctx;
const bool needs_lock = issue_flags & IO_URING_F_UNLOCKED;
/* workqueue context doesn't hold uring_lock, grab it now */
if (unlikely(needs_lock))
mutex_lock(&ctx->uring_lock);
/*
* Track whether we have multiple files in our lists. This will impact
* how we do polling eventually, not spinning if we're on potentially
* different devices.
*/
if (wq_list_empty(&ctx->iopoll_list)) {
ctx->poll_multi_queue = false;
} else if (!ctx->poll_multi_queue) {
struct io_kiocb *list_req;
list_req = container_of(ctx->iopoll_list.first, struct io_kiocb,
comp_list);
if (list_req->file != req->file)
ctx->poll_multi_queue = true;
}
/*
* For fast devices, IO may have already completed. If it has, add
* it to the front so we find it first.
*/
if (READ_ONCE(req->iopoll_completed))
wq_list_add_head(&req->comp_list, &ctx->iopoll_list);
else
wq_list_add_tail(&req->comp_list, &ctx->iopoll_list);
if (unlikely(needs_lock)) {
/*
* If IORING_SETUP_SQPOLL is enabled, sqes are either handle
* in sq thread task context or in io worker task context. If
* current task context is sq thread, we don't need to check
* whether should wake up sq thread.
*/
if ((ctx->flags & IORING_SETUP_SQPOLL) &&
wq_has_sleeper(&ctx->sq_data->wait))
wake_up(&ctx->sq_data->wait);
mutex_unlock(&ctx->uring_lock);
}
}
unsigned int io_file_get_flags(struct file *file)
{
unsigned int res = 0;
if (S_ISREG(file_inode(file)->i_mode))
res |= REQ_F_ISREG;
if ((file->f_flags & O_NONBLOCK) || (file->f_mode & FMODE_NOWAIT))
res |= REQ_F_SUPPORT_NOWAIT;
return res;
}
bool io_alloc_async_data(struct io_kiocb *req)
{
WARN_ON_ONCE(!io_cold_defs[req->opcode].async_size);
req->async_data = kmalloc(io_cold_defs[req->opcode].async_size, GFP_KERNEL);
if (req->async_data) {
req->flags |= REQ_F_ASYNC_DATA;
return false;
}
return true;
}
int io_req_prep_async(struct io_kiocb *req)
{
const struct io_cold_def *cdef = &io_cold_defs[req->opcode];
const struct io_issue_def *def = &io_issue_defs[req->opcode];
/* assign early for deferred execution for non-fixed file */
if (def->needs_file && !(req->flags & REQ_F_FIXED_FILE) && !req->file)
req->file = io_file_get_normal(req, req->cqe.fd);
if (!cdef->prep_async)
return 0;
if (WARN_ON_ONCE(req_has_async_data(req)))
return -EFAULT;
if (!def->manual_alloc) {
if (io_alloc_async_data(req))
return -EAGAIN;
}
return cdef->prep_async(req);
}
static u32 io_get_sequence(struct io_kiocb *req)
{
u32 seq = req->ctx->cached_sq_head;
struct io_kiocb *cur;
/* need original cached_sq_head, but it was increased for each req */
io_for_each_link(cur, req)
seq--;
return seq;
}
static __cold void io_drain_req(struct io_kiocb *req)
__must_hold(&ctx->uring_lock)
{
struct io_ring_ctx *ctx = req->ctx;
struct io_defer_entry *de;
int ret;
u32 seq = io_get_sequence(req);
/* Still need defer if there is pending req in defer list. */
spin_lock(&ctx->completion_lock);
if (!req_need_defer(req, seq) && list_empty_careful(&ctx->defer_list)) {
spin_unlock(&ctx->completion_lock);
queue:
ctx->drain_active = false;
io_req_task_queue(req);
return;
}
spin_unlock(&ctx->completion_lock);
io_prep_async_link(req);
de = kmalloc(sizeof(*de), GFP_KERNEL);
if (!de) {
ret = -ENOMEM;
io_req_defer_failed(req, ret);
return;
}
spin_lock(&ctx->completion_lock);
if (!req_need_defer(req, seq) && list_empty(&ctx->defer_list)) {
spin_unlock(&ctx->completion_lock);
kfree(de);
goto queue;
}
trace_io_uring_defer(req);
de->req = req;
de->seq = seq;
list_add_tail(&de->list, &ctx->defer_list);
spin_unlock(&ctx->completion_lock);
}
static bool io_assign_file(struct io_kiocb *req, const struct io_issue_def *def,
unsigned int issue_flags)
{
if (req->file || !def->needs_file)
return true;
if (req->flags & REQ_F_FIXED_FILE)
req->file = io_file_get_fixed(req, req->cqe.fd, issue_flags);
else
req->file = io_file_get_normal(req, req->cqe.fd);
return !!req->file;
}
static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags)
{
const struct io_issue_def *def = &io_issue_defs[req->opcode];
const struct cred *creds = NULL;
int ret;
if (unlikely(!io_assign_file(req, def, issue_flags)))
return -EBADF;
if (unlikely((req->flags & REQ_F_CREDS) && req->creds != current_cred()))
creds = override_creds(req->creds);
if (!def->audit_skip)
audit_uring_entry(req->opcode);
ret = def->issue(req, issue_flags);
if (!def->audit_skip)
audit_uring_exit(!ret, ret);
if (creds)
revert_creds(creds);
if (ret == IOU_OK) {
if (issue_flags & IO_URING_F_COMPLETE_DEFER)
io_req_complete_defer(req);
else
io_req_complete_post(req, issue_flags);
} else if (ret != IOU_ISSUE_SKIP_COMPLETE)
return ret;
/* If the op doesn't have a file, we're not polling for it */
if ((req->ctx->flags & IORING_SETUP_IOPOLL) && def->iopoll_queue)
io_iopoll_req_issued(req, issue_flags);
return 0;
}
int io_poll_issue(struct io_kiocb *req, struct io_tw_state *ts)
{
io_tw_lock(req->ctx, ts);
return io_issue_sqe(req, IO_URING_F_NONBLOCK|IO_URING_F_MULTISHOT|
IO_URING_F_COMPLETE_DEFER);
}
struct io_wq_work *io_wq_free_work(struct io_wq_work *work)
{
struct io_kiocb *req = container_of(work, struct io_kiocb, work);
struct io_kiocb *nxt = NULL;
if (req_ref_put_and_test(req)) {
if (req->flags & IO_REQ_LINK_FLAGS)
nxt = io_req_find_next(req);
io_free_req(req);
}
return nxt ? &nxt->work : NULL;
}
void io_wq_submit_work(struct io_wq_work *work)
{
struct io_kiocb *req = container_of(work, struct io_kiocb, work);
const struct io_issue_def *def = &io_issue_defs[req->opcode];
unsigned int issue_flags = IO_URING_F_UNLOCKED | IO_URING_F_IOWQ;
bool needs_poll = false;
int ret = 0, err = -ECANCELED;
/* one will be dropped by ->io_wq_free_work() after returning to io-wq */
if (!(req->flags & REQ_F_REFCOUNT))
__io_req_set_refcount(req, 2);
else
req_ref_get(req);
io_arm_ltimeout(req);
/* either cancelled or io-wq is dying, so don't touch tctx->iowq */
if (work->flags & IO_WQ_WORK_CANCEL) {
fail:
io_req_task_queue_fail(req, err);
return;
}
if (!io_assign_file(req, def, issue_flags)) {
err = -EBADF;
work->flags |= IO_WQ_WORK_CANCEL;
goto fail;
}
if (req->flags & REQ_F_FORCE_ASYNC) {
bool opcode_poll = def->pollin || def->pollout;
if (opcode_poll && file_can_poll(req->file)) {
needs_poll = true;
issue_flags |= IO_URING_F_NONBLOCK;
}
}
do {
ret = io_issue_sqe(req, issue_flags);
if (ret != -EAGAIN)
break;
/*
* If REQ_F_NOWAIT is set, then don't wait or retry with
* poll. -EAGAIN is final for that case.
*/
if (req->flags & REQ_F_NOWAIT)
break;
/*
* We can get EAGAIN for iopolled IO even though we're
* forcing a sync submission from here, since we can't
* wait for request slots on the block side.
*/
if (!needs_poll) {
if (!(req->ctx->flags & IORING_SETUP_IOPOLL))
break;
if (io_wq_worker_stopped())
break;
cond_resched();
continue;
}
if (io_arm_poll_handler(req, issue_flags) == IO_APOLL_OK)
return;
/* aborted or ready, in either case retry blocking */
needs_poll = false;
issue_flags &= ~IO_URING_F_NONBLOCK;
} while (1);
/* avoid locking problems by failing it from a clean context */
if (ret < 0)
io_req_task_queue_fail(req, ret);
}
inline struct file *io_file_get_fixed(struct io_kiocb *req, int fd,
unsigned int issue_flags)
{
struct io_ring_ctx *ctx = req->ctx;
struct io_fixed_file *slot;
struct file *file = NULL;
io_ring_submit_lock(ctx, issue_flags);
if (unlikely((unsigned int)fd >= ctx->nr_user_files))
goto out;
fd = array_index_nospec(fd, ctx->nr_user_files);
slot = io_fixed_file_slot(&ctx->file_table, fd);
file = io_slot_file(slot);
req->flags |= io_slot_flags(slot);
io_req_set_rsrc_node(req, ctx, 0);
out:
io_ring_submit_unlock(ctx, issue_flags);
return file;
}
struct file *io_file_get_normal(struct io_kiocb *req, int fd)
{
struct file *file = fget(fd);
trace_io_uring_file_get(req, fd);
/* we don't allow fixed io_uring files */
if (file && io_is_uring_fops(file))
io_req_track_inflight(req);
return file;
}
static void io_queue_async(struct io_kiocb *req, int ret)
__must_hold(&req->ctx->uring_lock)
{
struct io_kiocb *linked_timeout;
if (ret != -EAGAIN || (req->flags & REQ_F_NOWAIT)) {
io_req_defer_failed(req, ret);
return;
}
linked_timeout = io_prep_linked_timeout(req);
switch (io_arm_poll_handler(req, 0)) {
case IO_APOLL_READY:
io_kbuf_recycle(req, 0);
io_req_task_queue(req);
break;
case IO_APOLL_ABORTED:
io_kbuf_recycle(req, 0);
io_queue_iowq(req, NULL);
break;
case IO_APOLL_OK:
break;
}
if (linked_timeout)
io_queue_linked_timeout(linked_timeout);
}
static inline void io_queue_sqe(struct io_kiocb *req)
__must_hold(&req->ctx->uring_lock)
{
int ret;
ret = io_issue_sqe(req, IO_URING_F_NONBLOCK|IO_URING_F_COMPLETE_DEFER);
/*
* We async punt it if the file wasn't marked NOWAIT, or if the file
* doesn't support non-blocking read/write attempts
*/
if (likely(!ret))
io_arm_ltimeout(req);
else
io_queue_async(req, ret);
}
static void io_queue_sqe_fallback(struct io_kiocb *req)
__must_hold(&req->ctx->uring_lock)
{
if (unlikely(req->flags & REQ_F_FAIL)) {
/*
* We don't submit, fail them all, for that replace hardlinks
* with normal links. Extra REQ_F_LINK is tolerated.
*/
req->flags &= ~REQ_F_HARDLINK;
req->flags |= REQ_F_LINK;
io_req_defer_failed(req, req->cqe.res);
} else {
int ret = io_req_prep_async(req);
if (unlikely(ret)) {
io_req_defer_failed(req, ret);
return;
}
if (unlikely(req->ctx->drain_active))
io_drain_req(req);
else
io_queue_iowq(req, NULL);
}
}
/*
* Check SQE restrictions (opcode and flags).
*
* Returns 'true' if SQE is allowed, 'false' otherwise.
*/
static inline bool io_check_restriction(struct io_ring_ctx *ctx,
struct io_kiocb *req,
unsigned int sqe_flags)
{
if (!test_bit(req->opcode, ctx->restrictions.sqe_op))
return false;
if ((sqe_flags & ctx->restrictions.sqe_flags_required) !=
ctx->restrictions.sqe_flags_required)
return false;
if (sqe_flags & ~(ctx->restrictions.sqe_flags_allowed |
ctx->restrictions.sqe_flags_required))
return false;
return true;
}
static void io_init_req_drain(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
struct io_kiocb *head = ctx->submit_state.link.head;
ctx->drain_active = true;
if (head) {
/*
* If we need to drain a request in the middle of a link, drain
* the head request and the next request/link after the current
* link. Considering sequential execution of links,
* REQ_F_IO_DRAIN will be maintained for every request of our
* link.
*/
head->flags |= REQ_F_IO_DRAIN | REQ_F_FORCE_ASYNC;
ctx->drain_next = true;
}
}
static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req,
const struct io_uring_sqe *sqe)
__must_hold(&ctx->uring_lock)
{
const struct io_issue_def *def;
unsigned int sqe_flags;
int personality;
u8 opcode;
/* req is partially pre-initialised, see io_preinit_req() */
req->opcode = opcode = READ_ONCE(sqe->opcode);
/* same numerical values with corresponding REQ_F_*, safe to copy */
req->flags = sqe_flags = READ_ONCE(sqe->flags);
req->cqe.user_data = READ_ONCE(sqe->user_data);
req->file = NULL;
req->rsrc_node = NULL;
req->task = current;
if (unlikely(opcode >= IORING_OP_LAST)) {
req->opcode = 0;
return -EINVAL;
}
def = &io_issue_defs[opcode];
if (unlikely(sqe_flags & ~SQE_COMMON_FLAGS)) {
/* enforce forwards compatibility on users */
if (sqe_flags & ~SQE_VALID_FLAGS)
return -EINVAL;
if (sqe_flags & IOSQE_BUFFER_SELECT) {
if (!def->buffer_select)
return -EOPNOTSUPP;
req->buf_index = READ_ONCE(sqe->buf_group);
}
if (sqe_flags & IOSQE_CQE_SKIP_SUCCESS)
ctx->drain_disabled = true;
if (sqe_flags & IOSQE_IO_DRAIN) {
if (ctx->drain_disabled)
return -EOPNOTSUPP;
io_init_req_drain(req);
}
}
if (unlikely(ctx->restricted || ctx->drain_active || ctx->drain_next)) {
if (ctx->restricted && !io_check_restriction(ctx, req, sqe_flags))
return -EACCES;
/* knock it to the slow queue path, will be drained there */
if (ctx->drain_active)
req->flags |= REQ_F_FORCE_ASYNC;
/* if there is no link, we're at "next" request and need to drain */
if (unlikely(ctx->drain_next) && !ctx->submit_state.link.head) {
ctx->drain_next = false;
ctx->drain_active = true;
req->flags |= REQ_F_IO_DRAIN | REQ_F_FORCE_ASYNC;
}
}
if (!def->ioprio && sqe->ioprio)
return -EINVAL;
if (!def->iopoll && (ctx->flags & IORING_SETUP_IOPOLL))
return -EINVAL;
if (def->needs_file) {
struct io_submit_state *state = &ctx->submit_state;
req->cqe.fd = READ_ONCE(sqe->fd);
/*
* Plug now if we have more than 2 IO left after this, and the
* target is potentially a read/write to block based storage.
*/
if (state->need_plug && def->plug) {
state->plug_started = true;
state->need_plug = false;
blk_start_plug_nr_ios(&state->plug, state->submit_nr);
}
}
personality = READ_ONCE(sqe->personality);
if (personality) {
int ret;
req->creds = xa_load(&ctx->personalities, personality);
if (!req->creds)
return -EINVAL;
get_cred(req->creds);
ret = security_uring_override_creds(req->creds);
if (ret) {
put_cred(req->creds);
return ret;
}
req->flags |= REQ_F_CREDS;
}
return def->prep(req, sqe);
}
static __cold int io_submit_fail_init(const struct io_uring_sqe *sqe,
struct io_kiocb *req, int ret)
{
struct io_ring_ctx *ctx = req->ctx;
struct io_submit_link *link = &ctx->submit_state.link;
struct io_kiocb *head = link->head;
trace_io_uring_req_failed(sqe, req, ret);
/*
* Avoid breaking links in the middle as it renders links with SQPOLL
* unusable. Instead of failing eagerly, continue assembling the link if
* applicable and mark the head with REQ_F_FAIL. The link flushing code
* should find the flag and handle the rest.
*/
req_fail_link_node(req, ret);
if (head && !(head->flags & REQ_F_FAIL))
req_fail_link_node(head, -ECANCELED);
if (!(req->flags & IO_REQ_LINK_FLAGS)) {
if (head) {
link->last->link = req;
link->head = NULL;
req = head;
}
io_queue_sqe_fallback(req);
return ret;
}
if (head)
link->last->link = req;
else
link->head = req;
link->last = req;
return 0;
}
static inline int io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
const struct io_uring_sqe *sqe)
__must_hold(&ctx->uring_lock)
{
struct io_submit_link *link = &ctx->submit_state.link;
int ret;
ret = io_init_req(ctx, req, sqe);
if (unlikely(ret))
return io_submit_fail_init(sqe, req, ret);
trace_io_uring_submit_req(req);
/*
* If we already have a head request, queue this one for async
* submittal once the head completes. If we don't have a head but
* IOSQE_IO_LINK is set in the sqe, start a new head. This one will be
* submitted sync once the chain is complete. If none of those
* conditions are true (normal request), then just queue it.
*/
if (unlikely(link->head)) {
ret = io_req_prep_async(req);
if (unlikely(ret))
return io_submit_fail_init(sqe, req, ret);
trace_io_uring_link(req, link->head);
link->last->link = req;
link->last = req;
if (req->flags & IO_REQ_LINK_FLAGS)
return 0;
/* last request of the link, flush it */
req = link->head;
link->head = NULL;
if (req->flags & (REQ_F_FORCE_ASYNC | REQ_F_FAIL))
goto fallback;
} else if (unlikely(req->flags & (IO_REQ_LINK_FLAGS |
REQ_F_FORCE_ASYNC | REQ_F_FAIL))) {
if (req->flags & IO_REQ_LINK_FLAGS) {
link->head = req;
link->last = req;
} else {
fallback:
io_queue_sqe_fallback(req);
}
return 0;
}
io_queue_sqe(req);
return 0;
}
/*
* Batched submission is done, ensure local IO is flushed out.
*/
static void io_submit_state_end(struct io_ring_ctx *ctx)
{
struct io_submit_state *state = &ctx->submit_state;
if (unlikely(state->link.head))
io_queue_sqe_fallback(state->link.head);
/* flush only after queuing links as they can generate completions */
io_submit_flush_completions(ctx);
if (state->plug_started)
blk_finish_plug(&state->plug);
}
/*
* Start submission side cache.
*/
static void io_submit_state_start(struct io_submit_state *state,
unsigned int max_ios)
{
state->plug_started = false;
state->need_plug = max_ios > 2;
state->submit_nr = max_ios;
/* set only head, no need to init link_last in advance */
state->link.head = NULL;
}
static void io_commit_sqring(struct io_ring_ctx *ctx)
{
struct io_rings *rings = ctx->rings;
/*
* Ensure any loads from the SQEs are done at this point,
* since once we write the new head, the application could
* write new data to them.
*/
smp_store_release(&rings->sq.head, ctx->cached_sq_head);
}
/*
* Fetch an sqe, if one is available. Note this returns a pointer to memory
* that is mapped by userspace. This means that care needs to be taken to
* ensure that reads are stable, as we cannot rely on userspace always
* being a good citizen. If members of the sqe are validated and then later
* used, it's important that those reads are done through READ_ONCE() to
* prevent a re-load down the line.
*/
static bool io_get_sqe(struct io_ring_ctx *ctx, const struct io_uring_sqe **sqe)
{
unsigned mask = ctx->sq_entries - 1;
unsigned head = ctx->cached_sq_head++ & mask;
if (!(ctx->flags & IORING_SETUP_NO_SQARRAY)) {
head = READ_ONCE(ctx->sq_array[head]);
if (unlikely(head >= ctx->sq_entries)) {
/* drop invalid entries */
spin_lock(&ctx->completion_lock);
ctx->cq_extra--;
spin_unlock(&ctx->completion_lock);
WRITE_ONCE(ctx->rings->sq_dropped,
READ_ONCE(ctx->rings->sq_dropped) + 1);
return false;
}
}
/*
* The cached sq head (or cq tail) serves two purposes:
*
* 1) allows us to batch the cost of updating the user visible
* head updates.
* 2) allows the kernel side to track the head on its own, even
* though the application is the one updating it.
*/
/* double index for 128-byte SQEs, twice as long */
if (ctx->flags & IORING_SETUP_SQE128)
head <<= 1;
*sqe = &ctx->sq_sqes[head];
return true;
}
int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr)
__must_hold(&ctx->uring_lock)
{
unsigned int entries = io_sqring_entries(ctx);
unsigned int left;
int ret;
if (unlikely(!entries))
return 0;
/* make sure SQ entry isn't read before tail */
ret = left = min(nr, entries);
io_get_task_refs(left);
io_submit_state_start(&ctx->submit_state, left);
do {
const struct io_uring_sqe *sqe;
struct io_kiocb *req;
if (unlikely(!io_alloc_req(ctx, &req)))
break;
if (unlikely(!io_get_sqe(ctx, &sqe))) {
io_req_add_to_cache(req, ctx);
break;
}
/*
* Continue submitting even for sqe failure if the
* ring was setup with IORING_SETUP_SUBMIT_ALL
*/
if (unlikely(io_submit_sqe(ctx, req, sqe)) &&
!(ctx->flags & IORING_SETUP_SUBMIT_ALL)) {
left--;
break;
}
} while (--left);
if (unlikely(left)) {
ret -= left;
/* try again if it submitted nothing and can't allocate a req */
if (!ret && io_req_cache_empty(ctx))
ret = -EAGAIN;
current->io_uring->cached_refs += left;
}
io_submit_state_end(ctx);
/* Commit SQ ring head once we've consumed and submitted all SQEs */
io_commit_sqring(ctx);
return ret;
}
struct io_wait_queue {
struct wait_queue_entry wq;
struct io_ring_ctx *ctx;
unsigned cq_tail;
unsigned nr_timeouts;
ktime_t timeout;
};
static inline bool io_has_work(struct io_ring_ctx *ctx)
{
return test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq) ||
!llist_empty(&ctx->work_llist);
}
static inline bool io_should_wake(struct io_wait_queue *iowq)
{
struct io_ring_ctx *ctx = iowq->ctx;
int dist = READ_ONCE(ctx->rings->cq.tail) - (int) iowq->cq_tail;
/*
* Wake up if we have enough events, or if a timeout occurred since we
* started waiting. For timeouts, we always want to return to userspace,
* regardless of event count.
*/
return dist >= 0 || atomic_read(&ctx->cq_timeouts) != iowq->nr_timeouts;
}
static int io_wake_function(struct wait_queue_entry *curr, unsigned int mode,
int wake_flags, void *key)
{
struct io_wait_queue *iowq = container_of(curr, struct io_wait_queue, wq);
/*
* Cannot safely flush overflowed CQEs from here, ensure we wake up
* the task, and the next invocation will do it.
*/
if (io_should_wake(iowq) || io_has_work(iowq->ctx))
return autoremove_wake_function(curr, mode, wake_flags, key);
return -1;
}
int io_run_task_work_sig(struct io_ring_ctx *ctx)
{
if (!llist_empty(&ctx->work_llist)) {
__set_current_state(TASK_RUNNING);
if (io_run_local_work(ctx) > 0)
return 0;
}
if (io_run_task_work() > 0)
return 0;
if (task_sigpending(current))
return -EINTR;
return 0;
}
static bool current_pending_io(void)
{
struct io_uring_task *tctx = current->io_uring;
if (!tctx)
return false;
return percpu_counter_read_positive(&tctx->inflight);
}
/* when returns >0, the caller should retry */
static inline int io_cqring_wait_schedule(struct io_ring_ctx *ctx,
struct io_wait_queue *iowq)
{
int io_wait, ret;
if (unlikely(READ_ONCE(ctx->check_cq)))
return 1;
if (unlikely(!llist_empty(&ctx->work_llist)))
return 1;
if (unlikely(test_thread_flag(TIF_NOTIFY_SIGNAL)))
return 1;
if (unlikely(task_sigpending(current)))
return -EINTR;
if (unlikely(io_should_wake(iowq)))
return 0;
/*
* Mark us as being in io_wait if we have pending requests, so cpufreq
* can take into account that the task is waiting for IO - turns out
* to be important for low QD IO.
*/
io_wait = current->in_iowait;
if (current_pending_io())
current->in_iowait = 1;
ret = 0;
if (iowq->timeout == KTIME_MAX)
schedule();
else if (!schedule_hrtimeout(&iowq->timeout, HRTIMER_MODE_ABS))
ret = -ETIME;
current->in_iowait = io_wait;
return ret;
}
/*
* Wait until events become available, if we don't already have some. The
* application must reap them itself, as they reside on the shared cq ring.
*/
static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
const sigset_t __user *sig, size_t sigsz,
struct __kernel_timespec __user *uts)
{
struct io_wait_queue iowq;
struct io_rings *rings = ctx->rings;
int ret;
if (!io_allowed_run_tw(ctx))
return -EEXIST;
if (!llist_empty(&ctx->work_llist))
io_run_local_work(ctx);
io_run_task_work();
io_cqring_overflow_flush(ctx);
/* if user messes with these they will just get an early return */
if (__io_cqring_events_user(ctx) >= min_events)
return 0;
if (sig) {
#ifdef CONFIG_COMPAT
if (in_compat_syscall())
ret = set_compat_user_sigmask((const compat_sigset_t __user *)sig,
sigsz);
else
#endif
ret = set_user_sigmask(sig, sigsz);
if (ret)
return ret;
}
init_waitqueue_func_entry(&iowq.wq, io_wake_function);
iowq.wq.private = current;
INIT_LIST_HEAD(&iowq.wq.entry);
iowq.ctx = ctx;
iowq.nr_timeouts = atomic_read(&ctx->cq_timeouts);
iowq.cq_tail = READ_ONCE(ctx->rings->cq.head) + min_events;
iowq.timeout = KTIME_MAX;
if (uts) {
struct timespec64 ts;
if (get_timespec64(&ts, uts))
return -EFAULT;
iowq.timeout = ktime_add_ns(timespec64_to_ktime(ts), ktime_get_ns());
}
trace_io_uring_cqring_wait(ctx, min_events);
do {
unsigned long check_cq;
if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
int nr_wait = (int) iowq.cq_tail - READ_ONCE(ctx->rings->cq.tail);
atomic_set(&ctx->cq_wait_nr, nr_wait);
set_current_state(TASK_INTERRUPTIBLE);
} else {
prepare_to_wait_exclusive(&ctx->cq_wait, &iowq.wq,
TASK_INTERRUPTIBLE);
}
ret = io_cqring_wait_schedule(ctx, &iowq);
__set_current_state(TASK_RUNNING);
atomic_set(&ctx->cq_wait_nr, 0);
if (ret < 0)
break;
/*
* Run task_work after scheduling and before io_should_wake().
* If we got woken because of task_work being processed, run it
* now rather than let the caller do another wait loop.
*/
io_run_task_work();
if (!llist_empty(&ctx->work_llist))
io_run_local_work(ctx);
check_cq = READ_ONCE(ctx->check_cq);
if (unlikely(check_cq)) {
/* let the caller flush overflows, retry */
if (check_cq & BIT(IO_CHECK_CQ_OVERFLOW_BIT))
io_cqring_do_overflow_flush(ctx);
if (check_cq & BIT(IO_CHECK_CQ_DROPPED_BIT)) {
ret = -EBADR;
break;
}
}
if (io_should_wake(&iowq)) {
ret = 0;
break;
}
cond_resched();
} while (1);
if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN))
finish_wait(&ctx->cq_wait, &iowq.wq);
restore_saved_sigmask_unless(ret == -EINTR);
return READ_ONCE(rings->cq.head) == READ_ONCE(rings->cq.tail) ? ret : 0;
}
static void io_mem_free(void *ptr)
{
if (!ptr)
return;
folio_put(virt_to_folio(ptr));
}
static void io_pages_free(struct page ***pages, int npages)
{
struct page **page_array;
int i;
if (!pages)
return;
page_array = *pages;
for (i = 0; i < npages; i++)
unpin_user_page(page_array[i]);
kvfree(page_array);
*pages = NULL;
}
static void *__io_uaddr_map(struct page ***pages, unsigned short *npages,
unsigned long uaddr, size_t size)
{
struct page **page_array;
unsigned int nr_pages;
int ret;
*npages = 0;
if (uaddr & (PAGE_SIZE - 1) || !size)
return ERR_PTR(-EINVAL);
nr_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
if (nr_pages > USHRT_MAX)
return ERR_PTR(-EINVAL);
page_array = kvmalloc_array(nr_pages, sizeof(struct page *), GFP_KERNEL);
if (!page_array)
return ERR_PTR(-ENOMEM);
ret = pin_user_pages_fast(uaddr, nr_pages, FOLL_WRITE | FOLL_LONGTERM,
page_array);
if (ret != nr_pages) {
err:
io_pages_free(&page_array, ret > 0 ? ret : 0);
return ret < 0 ? ERR_PTR(ret) : ERR_PTR(-EFAULT);
}
/*
* Should be a single page. If the ring is small enough that we can
* use a normal page, that is fine. If we need multiple pages, then
* userspace should use a huge page. That's the only way to guarantee
* that we get contigious memory, outside of just being lucky or
* (currently) having low memory fragmentation.
*/
if (page_array[0] != page_array[ret - 1])
goto err;
*pages = page_array;
*npages = nr_pages;
return page_to_virt(page_array[0]);
}
static void *io_rings_map(struct io_ring_ctx *ctx, unsigned long uaddr,
size_t size)
{
return __io_uaddr_map(&ctx->ring_pages, &ctx->n_ring_pages, uaddr,
size);
}
static void *io_sqes_map(struct io_ring_ctx *ctx, unsigned long uaddr,
size_t size)
{
return __io_uaddr_map(&ctx->sqe_pages, &ctx->n_sqe_pages, uaddr,
size);
}
static void io_rings_free(struct io_ring_ctx *ctx)
{
if (!(ctx->flags & IORING_SETUP_NO_MMAP)) {
io_mem_free(ctx->rings);
io_mem_free(ctx->sq_sqes);
ctx->rings = NULL;
ctx->sq_sqes = NULL;
} else {
io_pages_free(&ctx->ring_pages, ctx->n_ring_pages);
io_pages_free(&ctx->sqe_pages, ctx->n_sqe_pages);
}
}
static void *io_mem_alloc(size_t size)
{
gfp_t gfp = GFP_KERNEL_ACCOUNT | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP;
void *ret;
ret = (void *) __get_free_pages(gfp, get_order(size));
if (ret)
return ret;
return ERR_PTR(-ENOMEM);
}
static unsigned long rings_size(struct io_ring_ctx *ctx, unsigned int sq_entries,
unsigned int cq_entries, size_t *sq_offset)
{
struct io_rings *rings;
size_t off, sq_array_size;
off = struct_size(rings, cqes, cq_entries);
if (off == SIZE_MAX)
return SIZE_MAX;
if (ctx->flags & IORING_SETUP_CQE32) {
if (check_shl_overflow(off, 1, &off))
return SIZE_MAX;
}
#ifdef CONFIG_SMP
off = ALIGN(off, SMP_CACHE_BYTES);
if (off == 0)
return SIZE_MAX;
#endif
if (ctx->flags & IORING_SETUP_NO_SQARRAY) {
if (sq_offset)
*sq_offset = SIZE_MAX;
return off;
}
if (sq_offset)
*sq_offset = off;
sq_array_size = array_size(sizeof(u32), sq_entries);
if (sq_array_size == SIZE_MAX)
return SIZE_MAX;
if (check_add_overflow(off, sq_array_size, &off))
return SIZE_MAX;
return off;
}
static int io_eventfd_register(struct io_ring_ctx *ctx, void __user *arg,
unsigned int eventfd_async)
{
struct io_ev_fd *ev_fd;
__s32 __user *fds = arg;
int fd;
ev_fd = rcu_dereference_protected(ctx->io_ev_fd,
lockdep_is_held(&ctx->uring_lock));
if (ev_fd)
return -EBUSY;
if (copy_from_user(&fd, fds, sizeof(*fds)))
return -EFAULT;
ev_fd = kmalloc(sizeof(*ev_fd), GFP_KERNEL);
if (!ev_fd)
return -ENOMEM;
ev_fd->cq_ev_fd = eventfd_ctx_fdget(fd);
if (IS_ERR(ev_fd->cq_ev_fd)) {
int ret = PTR_ERR(ev_fd->cq_ev_fd);
kfree(ev_fd);
return ret;
}
spin_lock(&ctx->completion_lock);
ctx->evfd_last_cq_tail = ctx->cached_cq_tail;
spin_unlock(&ctx->completion_lock);
ev_fd->eventfd_async = eventfd_async;
ctx->has_evfd = true;
rcu_assign_pointer(ctx->io_ev_fd, ev_fd);
atomic_set(&ev_fd->refs, 1);
atomic_set(&ev_fd->ops, 0);
return 0;
}
static int io_eventfd_unregister(struct io_ring_ctx *ctx)
{
struct io_ev_fd *ev_fd;
ev_fd = rcu_dereference_protected(ctx->io_ev_fd,
lockdep_is_held(&ctx->uring_lock));
if (ev_fd) {
ctx->has_evfd = false;
rcu_assign_pointer(ctx->io_ev_fd, NULL);
if (!atomic_fetch_or(BIT(IO_EVENTFD_OP_FREE_BIT), &ev_fd->ops))
call_rcu(&ev_fd->rcu, io_eventfd_ops);
return 0;
}
return -ENXIO;
}
static void io_req_caches_free(struct io_ring_ctx *ctx)
{
struct io_kiocb *req;
int nr = 0;
mutex_lock(&ctx->uring_lock);
io_flush_cached_locked_reqs(ctx, &ctx->submit_state);
while (!io_req_cache_empty(ctx)) {
req = io_extract_req(ctx);
kmem_cache_free(req_cachep, req);
nr++;
}
if (nr)
percpu_ref_put_many(&ctx->refs, nr);
mutex_unlock(&ctx->uring_lock);
}
static void io_rsrc_node_cache_free(struct io_cache_entry *entry)
{
kfree(container_of(entry, struct io_rsrc_node, cache));
}
static __cold void io_ring_ctx_free(struct io_ring_ctx *ctx)
{
io_sq_thread_finish(ctx);
/* __io_rsrc_put_work() may need uring_lock to progress, wait w/o it */
if (WARN_ON_ONCE(!list_empty(&ctx->rsrc_ref_list)))
return;
mutex_lock(&ctx->uring_lock);
if (ctx->buf_data)
__io_sqe_buffers_unregister(ctx);
if (ctx->file_data)
__io_sqe_files_unregister(ctx);
io_cqring_overflow_kill(ctx);
io_eventfd_unregister(ctx);
io_alloc_cache_free(&ctx->apoll_cache, io_apoll_cache_free);
io_alloc_cache_free(&ctx->netmsg_cache, io_netmsg_cache_free);
io_destroy_buffers(ctx);
mutex_unlock(&ctx->uring_lock);
if (ctx->sq_creds)
put_cred(ctx->sq_creds);
if (ctx->submitter_task)
put_task_struct(ctx->submitter_task);
/* there are no registered resources left, nobody uses it */
if (ctx->rsrc_node)
io_rsrc_node_destroy(ctx, ctx->rsrc_node);
WARN_ON_ONCE(!list_empty(&ctx->rsrc_ref_list));
#if defined(CONFIG_UNIX)
if (ctx->ring_sock) {
ctx->ring_sock->file = NULL; /* so that iput() is called */
sock_release(ctx->ring_sock);
}
#endif
WARN_ON_ONCE(!list_empty(&ctx->ltimeout_list));
io_alloc_cache_free(&ctx->rsrc_node_cache, io_rsrc_node_cache_free);
if (ctx->mm_account) {
mmdrop(ctx->mm_account);
ctx->mm_account = NULL;
}
io_rings_free(ctx);
percpu_ref_exit(&ctx->refs);
free_uid(ctx->user);
io_req_caches_free(ctx);
if (ctx->hash_map)
io_wq_put_hash(ctx->hash_map);
kfree(ctx->cancel_table.hbs);
kfree(ctx->cancel_table_locked.hbs);
kfree(ctx->io_bl);
xa_destroy(&ctx->io_bl_xa);
kfree(ctx);
}
static __cold void io_activate_pollwq_cb(struct callback_head *cb)
{
struct io_ring_ctx *ctx = container_of(cb, struct io_ring_ctx,
poll_wq_task_work);
mutex_lock(&ctx->uring_lock);
ctx->poll_activated = true;
mutex_unlock(&ctx->uring_lock);
/*
* Wake ups for some events between start of polling and activation
* might've been lost due to loose synchronisation.
*/
wake_up_all(&ctx->poll_wq);
percpu_ref_put(&ctx->refs);
}
static __cold void io_activate_pollwq(struct io_ring_ctx *ctx)
{
spin_lock(&ctx->completion_lock);
/* already activated or in progress */
if (ctx->poll_activated || ctx->poll_wq_task_work.func)
goto out;
if (WARN_ON_ONCE(!ctx->task_complete))
goto out;
if (!ctx->submitter_task)
goto out;
/*
* with ->submitter_task only the submitter task completes requests, we
* only need to sync with it, which is done by injecting a tw
*/
init_task_work(&ctx->poll_wq_task_work, io_activate_pollwq_cb);
percpu_ref_get(&ctx->refs);
if (task_work_add(ctx->submitter_task, &ctx->poll_wq_task_work, TWA_SIGNAL))
percpu_ref_put(&ctx->refs);
out:
spin_unlock(&ctx->completion_lock);
}
static __poll_t io_uring_poll(struct file *file, poll_table *wait)
{
struct io_ring_ctx *ctx = file->private_data;
__poll_t mask = 0;
if (unlikely(!ctx->poll_activated))
io_activate_pollwq(ctx);
poll_wait(file, &ctx->poll_wq, wait);
/*
* synchronizes with barrier from wq_has_sleeper call in
* io_commit_cqring
*/
smp_rmb();
if (!io_sqring_full(ctx))
mask |= EPOLLOUT | EPOLLWRNORM;
/*
* Don't flush cqring overflow list here, just do a simple check.
* Otherwise there could possible be ABBA deadlock:
* CPU0 CPU1
* ---- ----
* lock(&ctx->uring_lock);
* lock(&ep->mtx);
* lock(&ctx->uring_lock);
* lock(&ep->mtx);
*
* Users may get EPOLLIN meanwhile seeing nothing in cqring, this
* pushes them to do the flush.
*/
if (__io_cqring_events_user(ctx) || io_has_work(ctx))
mask |= EPOLLIN | EPOLLRDNORM;
return mask;
}
static int io_unregister_personality(struct io_ring_ctx *ctx, unsigned id)
{
const struct cred *creds;
creds = xa_erase(&ctx->personalities, id);
if (creds) {
put_cred(creds);
return 0;
}
return -EINVAL;
}
struct io_tctx_exit {
struct callback_head task_work;
struct completion completion;
struct io_ring_ctx *ctx;
};
static __cold void io_tctx_exit_cb(struct callback_head *cb)
{
struct io_uring_task *tctx = current->io_uring;
struct io_tctx_exit *work;
work = container_of(cb, struct io_tctx_exit, task_work);
/*
* When @in_cancel, we're in cancellation and it's racy to remove the
* node. It'll be removed by the end of cancellation, just ignore it.
* tctx can be NULL if the queueing of this task_work raced with
* work cancelation off the exec path.
*/
if (tctx && !atomic_read(&tctx->in_cancel))
io_uring_del_tctx_node((unsigned long)work->ctx);
complete(&work->completion);
}
static __cold bool io_cancel_ctx_cb(struct io_wq_work *work, void *data)
{
struct io_kiocb *req = container_of(work, struct io_kiocb, work);
return req->ctx == data;
}
static __cold void io_ring_exit_work(struct work_struct *work)
{
struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx, exit_work);
unsigned long timeout = jiffies + HZ * 60 * 5;
unsigned long interval = HZ / 20;
struct io_tctx_exit exit;
struct io_tctx_node *node;
int ret;
/*
* If we're doing polled IO and end up having requests being
* submitted async (out-of-line), then completions can come in while
* we're waiting for refs to drop. We need to reap these manually,
* as nobody else will be looking for them.
*/
do {
if (test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq)) {
mutex_lock(&ctx->uring_lock);
io_cqring_overflow_kill(ctx);
mutex_unlock(&ctx->uring_lock);
}
if (ctx->flags & IORING_SETUP_DEFER_TASKRUN)
io_move_task_work_from_local(ctx);
while (io_uring_try_cancel_requests(ctx, NULL, true))
cond_resched();
if (ctx->sq_data) {
struct io_sq_data *sqd = ctx->sq_data;
struct task_struct *tsk;
io_sq_thread_park(sqd);
tsk = sqd->thread;
if (tsk && tsk->io_uring && tsk->io_uring->io_wq)
io_wq_cancel_cb(tsk->io_uring->io_wq,
io_cancel_ctx_cb, ctx, true);
io_sq_thread_unpark(sqd);
}
io_req_caches_free(ctx);
if (WARN_ON_ONCE(time_after(jiffies, timeout))) {
/* there is little hope left, don't run it too often */
interval = HZ * 60;
}
/*
* This is really an uninterruptible wait, as it has to be
* complete. But it's also run from a kworker, which doesn't
* take signals, so it's fine to make it interruptible. This
* avoids scenarios where we knowingly can wait much longer
* on completions, for example if someone does a SIGSTOP on
* a task that needs to finish task_work to make this loop
* complete. That's a synthetic situation that should not
* cause a stuck task backtrace, and hence a potential panic
* on stuck tasks if that is enabled.
*/
} while (!wait_for_completion_interruptible_timeout(&ctx->ref_comp, interval));
init_completion(&exit.completion);
init_task_work(&exit.task_work, io_tctx_exit_cb);
exit.ctx = ctx;
/*
* Some may use context even when all refs and requests have been put,
* and they are free to do so while still holding uring_lock or
* completion_lock, see io_req_task_submit(). Apart from other work,
* this lock/unlock section also waits them to finish.
*/
mutex_lock(&ctx->uring_lock);
while (!list_empty(&ctx->tctx_list)) {
WARN_ON_ONCE(time_after(jiffies, timeout));
node = list_first_entry(&ctx->tctx_list, struct io_tctx_node,
ctx_node);
/* don't spin on a single task if cancellation failed */
list_rotate_left(&ctx->tctx_list);
ret = task_work_add(node->task, &exit.task_work, TWA_SIGNAL);
if (WARN_ON_ONCE(ret))
continue;
mutex_unlock(&ctx->uring_lock);
/*
* See comment above for
* wait_for_completion_interruptible_timeout() on why this
* wait is marked as interruptible.
*/
wait_for_completion_interruptible(&exit.completion);
mutex_lock(&ctx->uring_lock);
}
mutex_unlock(&ctx->uring_lock);
spin_lock(&ctx->completion_lock);
spin_unlock(&ctx->completion_lock);
/* pairs with RCU read section in io_req_local_work_add() */
if (ctx->flags & IORING_SETUP_DEFER_TASKRUN)
synchronize_rcu();
io_ring_ctx_free(ctx);
}
static __cold void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
{
unsigned long index;
struct creds *creds;
mutex_lock(&ctx->uring_lock);
percpu_ref_kill(&ctx->refs);
xa_for_each(&ctx->personalities, index, creds)
io_unregister_personality(ctx, index);
if (ctx->rings)
io_poll_remove_all(ctx, NULL, true);
mutex_unlock(&ctx->uring_lock);
/*
* If we failed setting up the ctx, we might not have any rings
* and therefore did not submit any requests
*/
if (ctx->rings)
io_kill_timeouts(ctx, NULL, true);
flush_delayed_work(&ctx->fallback_work);
INIT_WORK(&ctx->exit_work, io_ring_exit_work);
/*
* Use system_unbound_wq to avoid spawning tons of event kworkers
* if we're exiting a ton of rings at the same time. It just adds
* noise and overhead, there's no discernable change in runtime
* over using system_wq.
*/
queue_work(system_unbound_wq, &ctx->exit_work);
}
static int io_uring_release(struct inode *inode, struct file *file)
{
struct io_ring_ctx *ctx = file->private_data;
file->private_data = NULL;
io_ring_ctx_wait_and_kill(ctx);
return 0;
}
struct io_task_cancel {
struct task_struct *task;
bool all;
};
static bool io_cancel_task_cb(struct io_wq_work *work, void *data)
{
struct io_kiocb *req = container_of(work, struct io_kiocb, work);
struct io_task_cancel *cancel = data;
return io_match_task_safe(req, cancel->task, cancel->all);
}
static __cold bool io_cancel_defer_files(struct io_ring_ctx *ctx,
struct task_struct *task,
bool cancel_all)
{
struct io_defer_entry *de;
LIST_HEAD(list);
spin_lock(&ctx->completion_lock);
list_for_each_entry_reverse(de, &ctx->defer_list, list) {
if (io_match_task_safe(de->req, task, cancel_all)) {
list_cut_position(&list, &ctx->defer_list, &de->list);
break;
}
}
spin_unlock(&ctx->completion_lock);
if (list_empty(&list))
return false;
while (!list_empty(&list)) {
de = list_first_entry(&list, struct io_defer_entry, list);
list_del_init(&de->list);
io_req_task_queue_fail(de->req, -ECANCELED);
kfree(de);
}
return true;
}
static __cold bool io_uring_try_cancel_iowq(struct io_ring_ctx *ctx)
{
struct io_tctx_node *node;
enum io_wq_cancel cret;
bool ret = false;
mutex_lock(&ctx->uring_lock);
list_for_each_entry(node, &ctx->tctx_list, ctx_node) {
struct io_uring_task *tctx = node->task->io_uring;
/*
* io_wq will stay alive while we hold uring_lock, because it's
* killed after ctx nodes, which requires to take the lock.
*/
if (!tctx || !tctx->io_wq)
continue;
cret = io_wq_cancel_cb(tctx->io_wq, io_cancel_ctx_cb, ctx, true);
ret |= (cret != IO_WQ_CANCEL_NOTFOUND);
}
mutex_unlock(&ctx->uring_lock);
return ret;
}
static __cold bool io_uring_try_cancel_requests(struct io_ring_ctx *ctx,
struct task_struct *task,
bool cancel_all)
{
struct io_task_cancel cancel = { .task = task, .all = cancel_all, };
struct io_uring_task *tctx = task ? task->io_uring : NULL;
enum io_wq_cancel cret;
bool ret = false;
/* set it so io_req_local_work_add() would wake us up */
if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
atomic_set(&ctx->cq_wait_nr, 1);
smp_mb();
}
/* failed during ring init, it couldn't have issued any requests */
if (!ctx->rings)
return false;
if (!task) {
ret |= io_uring_try_cancel_iowq(ctx);
} else if (tctx && tctx->io_wq) {
/*
* Cancels requests of all rings, not only @ctx, but
* it's fine as the task is in exit/exec.
*/
cret = io_wq_cancel_cb(tctx->io_wq, io_cancel_task_cb,
&cancel, true);
ret |= (cret != IO_WQ_CANCEL_NOTFOUND);
}
/* SQPOLL thread does its own polling */
if ((!(ctx->flags & IORING_SETUP_SQPOLL) && cancel_all) ||
(ctx->sq_data && ctx->sq_data->thread == current)) {
while (!wq_list_empty(&ctx->iopoll_list)) {
io_iopoll_try_reap_events(ctx);
ret = true;
cond_resched();
}
}
if ((ctx->flags & IORING_SETUP_DEFER_TASKRUN) &&
io_allowed_defer_tw_run(ctx))
ret |= io_run_local_work(ctx) > 0;
ret |= io_cancel_defer_files(ctx, task, cancel_all);
mutex_lock(&ctx->uring_lock);
ret |= io_poll_remove_all(ctx, task, cancel_all);
mutex_unlock(&ctx->uring_lock);
ret |= io_kill_timeouts(ctx, task, cancel_all);
if (task)
ret |= io_run_task_work() > 0;
return ret;
}
static s64 tctx_inflight(struct io_uring_task *tctx, bool tracked)
{
if (tracked)
return atomic_read(&tctx->inflight_tracked);
return percpu_counter_sum(&tctx->inflight);
}
/*
* Find any io_uring ctx that this task has registered or done IO on, and cancel
* requests. @sqd should be not-null IFF it's an SQPOLL thread cancellation.
*/
__cold void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd)
{
struct io_uring_task *tctx = current->io_uring;
struct io_ring_ctx *ctx;
struct io_tctx_node *node;
unsigned long index;
s64 inflight;
DEFINE_WAIT(wait);
WARN_ON_ONCE(sqd && sqd->thread != current);
if (!current->io_uring)
return;
if (tctx->io_wq)
io_wq_exit_start(tctx->io_wq);
atomic_inc(&tctx->in_cancel);
do {
bool loop = false;
io_uring_drop_tctx_refs(current);
/* read completions before cancelations */
inflight = tctx_inflight(tctx, !cancel_all);
if (!inflight)
break;
if (!sqd) {
xa_for_each(&tctx->xa, index, node) {
/* sqpoll task will cancel all its requests */
if (node->ctx->sq_data)
continue;
loop |= io_uring_try_cancel_requests(node->ctx,
current, cancel_all);
}
} else {
list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
loop |= io_uring_try_cancel_requests(ctx,
current,
cancel_all);
}
if (loop) {
cond_resched();
continue;
}
prepare_to_wait(&tctx->wait, &wait, TASK_INTERRUPTIBLE);
io_run_task_work();
io_uring_drop_tctx_refs(current);
xa_for_each(&tctx->xa, index, node) {
if (!llist_empty(&node->ctx->work_llist)) {
WARN_ON_ONCE(node->ctx->submitter_task &&
node->ctx->submitter_task != current);
goto end_wait;
}
}
/*
* If we've seen completions, retry without waiting. This
* avoids a race where a completion comes in before we did
* prepare_to_wait().
*/
if (inflight == tctx_inflight(tctx, !cancel_all))
schedule();
end_wait:
finish_wait(&tctx->wait, &wait);
} while (1);
io_uring_clean_tctx(tctx);
if (cancel_all) {
/*
* We shouldn't run task_works after cancel, so just leave
* ->in_cancel set for normal exit.
*/
atomic_dec(&tctx->in_cancel);
/* for exec all current's requests should be gone, kill tctx */
__io_uring_free(current);
}
}
void __io_uring_cancel(bool cancel_all)
{
io_uring_cancel_generic(cancel_all, NULL);
}
static void *io_uring_validate_mmap_request(struct file *file,
loff_t pgoff, size_t sz)
{
struct io_ring_ctx *ctx = file->private_data;
loff_t offset = pgoff << PAGE_SHIFT;
struct page *page;
void *ptr;
/* Don't allow mmap if the ring was setup without it */
if (ctx->flags & IORING_SETUP_NO_MMAP)
return ERR_PTR(-EINVAL);
switch (offset & IORING_OFF_MMAP_MASK) {
case IORING_OFF_SQ_RING:
case IORING_OFF_CQ_RING:
ptr = ctx->rings;
break;
case IORING_OFF_SQES:
ptr = ctx->sq_sqes;
break;
case IORING_OFF_PBUF_RING: {
unsigned int bgid;
bgid = (offset & ~IORING_OFF_MMAP_MASK) >> IORING_OFF_PBUF_SHIFT;
mutex_lock(&ctx->uring_lock);
ptr = io_pbuf_get_address(ctx, bgid);
mutex_unlock(&ctx->uring_lock);
if (!ptr)
return ERR_PTR(-EINVAL);
break;
}
default:
return ERR_PTR(-EINVAL);
}
page = virt_to_head_page(ptr);
if (sz > page_size(page))
return ERR_PTR(-EINVAL);
return ptr;
}
#ifdef CONFIG_MMU
static __cold int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
{
size_t sz = vma->vm_end - vma->vm_start;
unsigned long pfn;
void *ptr;
ptr = io_uring_validate_mmap_request(file, vma->vm_pgoff, sz);
if (IS_ERR(ptr))
return PTR_ERR(ptr);
pfn = virt_to_phys(ptr) >> PAGE_SHIFT;
return remap_pfn_range(vma, vma->vm_start, pfn, sz, vma->vm_page_prot);
}
static unsigned long io_uring_mmu_get_unmapped_area(struct file *filp,
unsigned long addr, unsigned long len,
unsigned long pgoff, unsigned long flags)
{
void *ptr;
/*
* Do not allow to map to user-provided address to avoid breaking the
* aliasing rules. Userspace is not able to guess the offset address of
* kernel kmalloc()ed memory area.
*/
if (addr)
return -EINVAL;
ptr = io_uring_validate_mmap_request(filp, pgoff, len);
if (IS_ERR(ptr))
return -ENOMEM;
/*
* Some architectures have strong cache aliasing requirements.
* For such architectures we need a coherent mapping which aliases
* kernel memory *and* userspace memory. To achieve that:
* - use a NULL file pointer to reference physical memory, and
* - use the kernel virtual address of the shared io_uring context
* (instead of the userspace-provided address, which has to be 0UL
* anyway).
* - use the same pgoff which the get_unmapped_area() uses to
* calculate the page colouring.
* For architectures without such aliasing requirements, the
* architecture will return any suitable mapping because addr is 0.
*/
filp = NULL;
flags |= MAP_SHARED;
pgoff = 0; /* has been translated to ptr above */
#ifdef SHM_COLOUR
addr = (uintptr_t) ptr;
pgoff = addr >> PAGE_SHIFT;
#else
addr = 0UL;
#endif
return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags);
}
#else /* !CONFIG_MMU */
static int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
{
return is_nommu_shared_mapping(vma->vm_flags) ? 0 : -EINVAL;
}
static unsigned int io_uring_nommu_mmap_capabilities(struct file *file)
{
return NOMMU_MAP_DIRECT | NOMMU_MAP_READ | NOMMU_MAP_WRITE;
}
static unsigned long io_uring_nommu_get_unmapped_area(struct file *file,
unsigned long addr, unsigned long len,
unsigned long pgoff, unsigned long flags)
{
void *ptr;
ptr = io_uring_validate_mmap_request(file, pgoff, len);
if (IS_ERR(ptr))
return PTR_ERR(ptr);
return (unsigned long) ptr;
}
#endif /* !CONFIG_MMU */
static int io_validate_ext_arg(unsigned flags, const void __user *argp, size_t argsz)
{
if (flags & IORING_ENTER_EXT_ARG) {
struct io_uring_getevents_arg arg;
if (argsz != sizeof(arg))
return -EINVAL;
if (copy_from_user(&arg, argp, sizeof(arg)))
return -EFAULT;
}
return 0;
}
static int io_get_ext_arg(unsigned flags, const void __user *argp, size_t *argsz,
struct __kernel_timespec __user **ts,
const sigset_t __user **sig)
{
struct io_uring_getevents_arg arg;
/*
* If EXT_ARG isn't set, then we have no timespec and the argp pointer
* is just a pointer to the sigset_t.
*/
if (!(flags & IORING_ENTER_EXT_ARG)) {
*sig = (const sigset_t __user *) argp;
*ts = NULL;
return 0;
}
/*
* EXT_ARG is set - ensure we agree on the size of it and copy in our
* timespec and sigset_t pointers if good.
*/
if (*argsz != sizeof(arg))
return -EINVAL;
if (copy_from_user(&arg, argp, sizeof(arg)))
return -EFAULT;
if (arg.pad)
return -EINVAL;
*sig = u64_to_user_ptr(arg.sigmask);
*argsz = arg.sigmask_sz;
*ts = u64_to_user_ptr(arg.ts);
return 0;
}
SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
u32, min_complete, u32, flags, const void __user *, argp,
size_t, argsz)
{
struct io_ring_ctx *ctx;
struct fd f;
long ret;
if (unlikely(flags & ~(IORING_ENTER_GETEVENTS | IORING_ENTER_SQ_WAKEUP |
IORING_ENTER_SQ_WAIT | IORING_ENTER_EXT_ARG |
IORING_ENTER_REGISTERED_RING)))
return -EINVAL;
/*
* Ring fd has been registered via IORING_REGISTER_RING_FDS, we
* need only dereference our task private array to find it.
*/
if (flags & IORING_ENTER_REGISTERED_RING) {
struct io_uring_task *tctx = current->io_uring;
if (unlikely(!tctx || fd >= IO_RINGFD_REG_MAX))
return -EINVAL;
fd = array_index_nospec(fd, IO_RINGFD_REG_MAX);
f.file = tctx->registered_rings[fd];
f.flags = 0;
if (unlikely(!f.file))
return -EBADF;
} else {
f = fdget(fd);
if (unlikely(!f.file))
return -EBADF;
ret = -EOPNOTSUPP;
if (unlikely(!io_is_uring_fops(f.file)))
goto out;
}
ctx = f.file->private_data;
ret = -EBADFD;
if (unlikely(ctx->flags & IORING_SETUP_R_DISABLED))
goto out;
/*
* For SQ polling, the thread will do all submissions and completions.
* Just return the requested submit count, and wake the thread if
* we were asked to.
*/
ret = 0;
if (ctx->flags & IORING_SETUP_SQPOLL) {
io_cqring_overflow_flush(ctx);
if (unlikely(ctx->sq_data->thread == NULL)) {
ret = -EOWNERDEAD;
goto out;
}
if (flags & IORING_ENTER_SQ_WAKEUP)
wake_up(&ctx->sq_data->wait);
if (flags & IORING_ENTER_SQ_WAIT)
io_sqpoll_wait_sq(ctx);
ret = to_submit;
} else if (to_submit) {
ret = io_uring_add_tctx_node(ctx);
if (unlikely(ret))
goto out;
mutex_lock(&ctx->uring_lock);
ret = io_submit_sqes(ctx, to_submit);
if (ret != to_submit) {
mutex_unlock(&ctx->uring_lock);
goto out;
}
if (flags & IORING_ENTER_GETEVENTS) {
if (ctx->syscall_iopoll)
goto iopoll_locked;
/*
* Ignore errors, we'll soon call io_cqring_wait() and
* it should handle ownership problems if any.
*/
if (ctx->flags & IORING_SETUP_DEFER_TASKRUN)
(void)io_run_local_work_locked(ctx);
}
mutex_unlock(&ctx->uring_lock);
}
if (flags & IORING_ENTER_GETEVENTS) {
int ret2;
if (ctx->syscall_iopoll) {
/*
* We disallow the app entering submit/complete with
* polling, but we still need to lock the ring to
* prevent racing with polled issue that got punted to
* a workqueue.
*/
mutex_lock(&ctx->uring_lock);
iopoll_locked:
ret2 = io_validate_ext_arg(flags, argp, argsz);
if (likely(!ret2)) {
min_complete = min(min_complete,
ctx->cq_entries);
ret2 = io_iopoll_check(ctx, min_complete);
}
mutex_unlock(&ctx->uring_lock);
} else {
const sigset_t __user *sig;
struct __kernel_timespec __user *ts;
ret2 = io_get_ext_arg(flags, argp, &argsz, &ts, &sig);
if (likely(!ret2)) {
min_complete = min(min_complete,
ctx->cq_entries);
ret2 = io_cqring_wait(ctx, min_complete, sig,
argsz, ts);
}
}
if (!ret) {
ret = ret2;
/*
* EBADR indicates that one or more CQE were dropped.
* Once the user has been informed we can clear the bit
* as they are obviously ok with those drops.
*/
if (unlikely(ret2 == -EBADR))
clear_bit(IO_CHECK_CQ_DROPPED_BIT,
&ctx->check_cq);
}
}
out:
fdput(f);
return ret;
}
static const struct file_operations io_uring_fops = {
.release = io_uring_release,
.mmap = io_uring_mmap,
#ifndef CONFIG_MMU
.get_unmapped_area = io_uring_nommu_get_unmapped_area,
.mmap_capabilities = io_uring_nommu_mmap_capabilities,
#else
.get_unmapped_area = io_uring_mmu_get_unmapped_area,
#endif
.poll = io_uring_poll,
#ifdef CONFIG_PROC_FS
.show_fdinfo = io_uring_show_fdinfo,
#endif
};
bool io_is_uring_fops(struct file *file)
{
return file->f_op == &io_uring_fops;
}
static __cold int io_allocate_scq_urings(struct io_ring_ctx *ctx,
struct io_uring_params *p)
{
struct io_rings *rings;
size_t size, sq_array_offset;
void *ptr;
/* make sure these are sane, as we already accounted them */
ctx->sq_entries = p->sq_entries;
ctx->cq_entries = p->cq_entries;
size = rings_size(ctx, p->sq_entries, p->cq_entries, &sq_array_offset);
if (size == SIZE_MAX)
return -EOVERFLOW;
if (!(ctx->flags & IORING_SETUP_NO_MMAP))
rings = io_mem_alloc(size);
else
rings = io_rings_map(ctx, p->cq_off.user_addr, size);
if (IS_ERR(rings))
return PTR_ERR(rings);
ctx->rings = rings;
if (!(ctx->flags & IORING_SETUP_NO_SQARRAY))
ctx->sq_array = (u32 *)((char *)rings + sq_array_offset);
rings->sq_ring_mask = p->sq_entries - 1;
rings->cq_ring_mask = p->cq_entries - 1;
rings->sq_ring_entries = p->sq_entries;
rings->cq_ring_entries = p->cq_entries;
if (p->flags & IORING_SETUP_SQE128)
size = array_size(2 * sizeof(struct io_uring_sqe), p->sq_entries);
else
size = array_size(sizeof(struct io_uring_sqe), p->sq_entries);
if (size == SIZE_MAX) {
io_rings_free(ctx);
return -EOVERFLOW;
}
if (!(ctx->flags & IORING_SETUP_NO_MMAP))
ptr = io_mem_alloc(size);
else
ptr = io_sqes_map(ctx, p->sq_off.user_addr, size);
if (IS_ERR(ptr)) {
io_rings_free(ctx);
return PTR_ERR(ptr);
}
ctx->sq_sqes = ptr;
return 0;
}
static int io_uring_install_fd(struct file *file)
{
int fd;
fd = get_unused_fd_flags(O_RDWR | O_CLOEXEC);
if (fd < 0)
return fd;
fd_install(fd, file);
return fd;
}
/*
* Allocate an anonymous fd, this is what constitutes the application
* visible backing of an io_uring instance. The application mmaps this
* fd to gain access to the SQ/CQ ring details. If UNIX sockets are enabled,
* we have to tie this fd to a socket for file garbage collection purposes.
*/
static struct file *io_uring_get_file(struct io_ring_ctx *ctx)
{
struct file *file;
#if defined(CONFIG_UNIX)
int ret;
ret = sock_create_kern(&init_net, PF_UNIX, SOCK_RAW, IPPROTO_IP,
&ctx->ring_sock);
if (ret)
return ERR_PTR(ret);
#endif
file = anon_inode_getfile_secure("[io_uring]", &io_uring_fops, ctx,
O_RDWR | O_CLOEXEC, NULL);
#if defined(CONFIG_UNIX)
if (IS_ERR(file)) {
sock_release(ctx->ring_sock);
ctx->ring_sock = NULL;
} else {
ctx->ring_sock->file = file;
}
#endif
return file;
}
static __cold int io_uring_create(unsigned entries, struct io_uring_params *p,
struct io_uring_params __user *params)
{
struct io_ring_ctx *ctx;
struct io_uring_task *tctx;
struct file *file;
int ret;
if (!entries)
return -EINVAL;
if (entries > IORING_MAX_ENTRIES) {
if (!(p->flags & IORING_SETUP_CLAMP))
return -EINVAL;
entries = IORING_MAX_ENTRIES;
}
if ((p->flags & IORING_SETUP_REGISTERED_FD_ONLY)
&& !(p->flags & IORING_SETUP_NO_MMAP))
return -EINVAL;
/*
* Use twice as many entries for the CQ ring. It's possible for the
* application to drive a higher depth than the size of the SQ ring,
* since the sqes are only used at submission time. This allows for
* some flexibility in overcommitting a bit. If the application has
* set IORING_SETUP_CQSIZE, it will have passed in the desired number
* of CQ ring entries manually.
*/
p->sq_entries = roundup_pow_of_two(entries);
if (p->flags & IORING_SETUP_CQSIZE) {
/*
* If IORING_SETUP_CQSIZE is set, we do the same roundup
* to a power-of-two, if it isn't already. We do NOT impose
* any cq vs sq ring sizing.
*/
if (!p->cq_entries)
return -EINVAL;
if (p->cq_entries > IORING_MAX_CQ_ENTRIES) {
if (!(p->flags & IORING_SETUP_CLAMP))
return -EINVAL;
p->cq_entries = IORING_MAX_CQ_ENTRIES;
}
p->cq_entries = roundup_pow_of_two(p->cq_entries);
if (p->cq_entries < p->sq_entries)
return -EINVAL;
} else {
p->cq_entries = 2 * p->sq_entries;
}
ctx = io_ring_ctx_alloc(p);
if (!ctx)
return -ENOMEM;
if ((ctx->flags & IORING_SETUP_DEFER_TASKRUN) &&
!(ctx->flags & IORING_SETUP_IOPOLL) &&
!(ctx->flags & IORING_SETUP_SQPOLL))
ctx->task_complete = true;
if (ctx->task_complete || (ctx->flags & IORING_SETUP_IOPOLL))
ctx->lockless_cq = true;
/*
* lazy poll_wq activation relies on ->task_complete for synchronisation
* purposes, see io_activate_pollwq()
*/
if (!ctx->task_complete)
ctx->poll_activated = true;
/*
* When SETUP_IOPOLL and SETUP_SQPOLL are both enabled, user
* space applications don't need to do io completion events
* polling again, they can rely on io_sq_thread to do polling
* work, which can reduce cpu usage and uring_lock contention.
*/
if (ctx->flags & IORING_SETUP_IOPOLL &&
!(ctx->flags & IORING_SETUP_SQPOLL))
ctx->syscall_iopoll = 1;
ctx->compat = in_compat_syscall();
if (!ns_capable_noaudit(&init_user_ns, CAP_IPC_LOCK))
ctx->user = get_uid(current_user());
/*
* For SQPOLL, we just need a wakeup, always. For !SQPOLL, if
* COOP_TASKRUN is set, then IPIs are never needed by the app.
*/
ret = -EINVAL;
if (ctx->flags & IORING_SETUP_SQPOLL) {
/* IPI related flags don't make sense with SQPOLL */
if (ctx->flags & (IORING_SETUP_COOP_TASKRUN |
IORING_SETUP_TASKRUN_FLAG |
IORING_SETUP_DEFER_TASKRUN))
goto err;
ctx->notify_method = TWA_SIGNAL_NO_IPI;
} else if (ctx->flags & IORING_SETUP_COOP_TASKRUN) {
ctx->notify_method = TWA_SIGNAL_NO_IPI;
} else {
if (ctx->flags & IORING_SETUP_TASKRUN_FLAG &&
!(ctx->flags & IORING_SETUP_DEFER_TASKRUN))
goto err;
ctx->notify_method = TWA_SIGNAL;
}
/*
* For DEFER_TASKRUN we require the completion task to be the same as the
* submission task. This implies that there is only one submitter, so enforce
* that.
*/
if (ctx->flags & IORING_SETUP_DEFER_TASKRUN &&
!(ctx->flags & IORING_SETUP_SINGLE_ISSUER)) {
goto err;
}
/*
* This is just grabbed for accounting purposes. When a process exits,
* the mm is exited and dropped before the files, hence we need to hang
* on to this mm purely for the purposes of being able to unaccount
* memory (locked/pinned vm). It's not used for anything else.
*/
mmgrab(current->mm);
ctx->mm_account = current->mm;
ret = io_allocate_scq_urings(ctx, p);
if (ret)
goto err;
ret = io_sq_offload_create(ctx, p);
if (ret)
goto err;
ret = io_rsrc_init(ctx);
if (ret)
goto err;
p->sq_off.head = offsetof(struct io_rings, sq.head);
p->sq_off.tail = offsetof(struct io_rings, sq.tail);
p->sq_off.ring_mask = offsetof(struct io_rings, sq_ring_mask);
p->sq_off.ring_entries = offsetof(struct io_rings, sq_ring_entries);
p->sq_off.flags = offsetof(struct io_rings, sq_flags);
p->sq_off.dropped = offsetof(struct io_rings, sq_dropped);
if (!(ctx->flags & IORING_SETUP_NO_SQARRAY))
p->sq_off.array = (char *)ctx->sq_array - (char *)ctx->rings;
p->sq_off.resv1 = 0;
if (!(ctx->flags & IORING_SETUP_NO_MMAP))
p->sq_off.user_addr = 0;
p->cq_off.head = offsetof(struct io_rings, cq.head);
p->cq_off.tail = offsetof(struct io_rings, cq.tail);
p->cq_off.ring_mask = offsetof(struct io_rings, cq_ring_mask);
p->cq_off.ring_entries = offsetof(struct io_rings, cq_ring_entries);
p->cq_off.overflow = offsetof(struct io_rings, cq_overflow);
p->cq_off.cqes = offsetof(struct io_rings, cqes);
p->cq_off.flags = offsetof(struct io_rings, cq_flags);
p->cq_off.resv1 = 0;
if (!(ctx->flags & IORING_SETUP_NO_MMAP))
p->cq_off.user_addr = 0;
p->features = IORING_FEAT_SINGLE_MMAP | IORING_FEAT_NODROP |
IORING_FEAT_SUBMIT_STABLE | IORING_FEAT_RW_CUR_POS |
IORING_FEAT_CUR_PERSONALITY | IORING_FEAT_FAST_POLL |
IORING_FEAT_POLL_32BITS | IORING_FEAT_SQPOLL_NONFIXED |
IORING_FEAT_EXT_ARG | IORING_FEAT_NATIVE_WORKERS |
IORING_FEAT_RSRC_TAGS | IORING_FEAT_CQE_SKIP |
IORING_FEAT_LINKED_FILE | IORING_FEAT_REG_REG_RING;
if (copy_to_user(params, p, sizeof(*p))) {
ret = -EFAULT;
goto err;
}
if (ctx->flags & IORING_SETUP_SINGLE_ISSUER
&& !(ctx->flags & IORING_SETUP_R_DISABLED))
WRITE_ONCE(ctx->submitter_task, get_task_struct(current));
file = io_uring_get_file(ctx);
if (IS_ERR(file)) {
ret = PTR_ERR(file);
goto err;
}
ret = __io_uring_add_tctx_node(ctx);
if (ret)
goto err_fput;
tctx = current->io_uring;
/*
* Install ring fd as the very last thing, so we don't risk someone
* having closed it before we finish setup
*/
if (p->flags & IORING_SETUP_REGISTERED_FD_ONLY)
ret = io_ring_add_registered_file(tctx, file, 0, IO_RINGFD_REG_MAX);
else
ret = io_uring_install_fd(file);
if (ret < 0)
goto err_fput;
trace_io_uring_create(ret, ctx, p->sq_entries, p->cq_entries, p->flags);
return ret;
err:
io_ring_ctx_wait_and_kill(ctx);
return ret;
err_fput:
fput(file);
return ret;
}
/*
* Sets up an aio uring context, and returns the fd. Applications asks for a
* ring size, we return the actual sq/cq ring sizes (among other things) in the
* params structure passed in.
*/
static long io_uring_setup(u32 entries, struct io_uring_params __user *params)
{
struct io_uring_params p;
int i;
if (copy_from_user(&p, params, sizeof(p)))
return -EFAULT;
for (i = 0; i < ARRAY_SIZE(p.resv); i++) {
if (p.resv[i])
return -EINVAL;
}
if (p.flags & ~(IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL |
IORING_SETUP_SQ_AFF | IORING_SETUP_CQSIZE |
IORING_SETUP_CLAMP | IORING_SETUP_ATTACH_WQ |
IORING_SETUP_R_DISABLED | IORING_SETUP_SUBMIT_ALL |
IORING_SETUP_COOP_TASKRUN | IORING_SETUP_TASKRUN_FLAG |
IORING_SETUP_SQE128 | IORING_SETUP_CQE32 |
IORING_SETUP_SINGLE_ISSUER | IORING_SETUP_DEFER_TASKRUN |
IORING_SETUP_NO_MMAP | IORING_SETUP_REGISTERED_FD_ONLY |
IORING_SETUP_NO_SQARRAY))
return -EINVAL;
return io_uring_create(entries, &p, params);
}
static inline bool io_uring_allowed(void)
{
int disabled = READ_ONCE(sysctl_io_uring_disabled);
kgid_t io_uring_group;
if (disabled == 2)
return false;
if (disabled == 0 || capable(CAP_SYS_ADMIN))
return true;
io_uring_group = make_kgid(&init_user_ns, sysctl_io_uring_group);
if (!gid_valid(io_uring_group))
return false;
return in_group_p(io_uring_group);
}
SYSCALL_DEFINE2(io_uring_setup, u32, entries,
struct io_uring_params __user *, params)
{
if (!io_uring_allowed())
return -EPERM;
return io_uring_setup(entries, params);
}
static __cold int io_probe(struct io_ring_ctx *ctx, void __user *arg,
unsigned nr_args)
{
struct io_uring_probe *p;
size_t size;
int i, ret;
size = struct_size(p, ops, nr_args);
if (size == SIZE_MAX)
return -EOVERFLOW;
p = kzalloc(size, GFP_KERNEL);
if (!p)
return -ENOMEM;
ret = -EFAULT;
if (copy_from_user(p, arg, size))
goto out;
ret = -EINVAL;
if (memchr_inv(p, 0, size))
goto out;
p->last_op = IORING_OP_LAST - 1;
if (nr_args > IORING_OP_LAST)
nr_args = IORING_OP_LAST;
for (i = 0; i < nr_args; i++) {
p->ops[i].op = i;
if (!io_issue_defs[i].not_supported)
p->ops[i].flags = IO_URING_OP_SUPPORTED;
}
p->ops_len = i;
ret = 0;
if (copy_to_user(arg, p, size))
ret = -EFAULT;
out:
kfree(p);
return ret;
}
static int io_register_personality(struct io_ring_ctx *ctx)
{
const struct cred *creds;
u32 id;
int ret;
creds = get_current_cred();
ret = xa_alloc_cyclic(&ctx->personalities, &id, (void *)creds,
XA_LIMIT(0, USHRT_MAX), &ctx->pers_next, GFP_KERNEL);
if (ret < 0) {
put_cred(creds);
return ret;
}
return id;
}
static __cold int io_register_restrictions(struct io_ring_ctx *ctx,
void __user *arg, unsigned int nr_args)
{
struct io_uring_restriction *res;
size_t size;
int i, ret;
/* Restrictions allowed only if rings started disabled */
if (!(ctx->flags & IORING_SETUP_R_DISABLED))
return -EBADFD;
/* We allow only a single restrictions registration */
if (ctx->restrictions.registered)
return -EBUSY;
if (!arg || nr_args > IORING_MAX_RESTRICTIONS)
return -EINVAL;
size = array_size(nr_args, sizeof(*res));
if (size == SIZE_MAX)
return -EOVERFLOW;
res = memdup_user(arg, size);
if (IS_ERR(res))
return PTR_ERR(res);
ret = 0;
for (i = 0; i < nr_args; i++) {
switch (res[i].opcode) {
case IORING_RESTRICTION_REGISTER_OP:
if (res[i].register_op >= IORING_REGISTER_LAST) {
ret = -EINVAL;
goto out;
}
__set_bit(res[i].register_op,
ctx->restrictions.register_op);
break;
case IORING_RESTRICTION_SQE_OP:
if (res[i].sqe_op >= IORING_OP_LAST) {
ret = -EINVAL;
goto out;
}
__set_bit(res[i].sqe_op, ctx->restrictions.sqe_op);
break;
case IORING_RESTRICTION_SQE_FLAGS_ALLOWED:
ctx->restrictions.sqe_flags_allowed = res[i].sqe_flags;
break;
case IORING_RESTRICTION_SQE_FLAGS_REQUIRED:
ctx->restrictions.sqe_flags_required = res[i].sqe_flags;
break;
default:
ret = -EINVAL;
goto out;
}
}
out:
/* Reset all restrictions if an error happened */
if (ret != 0)
memset(&ctx->restrictions, 0, sizeof(ctx->restrictions));
else
ctx->restrictions.registered = true;
kfree(res);
return ret;
}
static int io_register_enable_rings(struct io_ring_ctx *ctx)
{
if (!(ctx->flags & IORING_SETUP_R_DISABLED))
return -EBADFD;
if (ctx->flags & IORING_SETUP_SINGLE_ISSUER && !ctx->submitter_task) {
WRITE_ONCE(ctx->submitter_task, get_task_struct(current));
/*
* Lazy activation attempts would fail if it was polled before
* submitter_task is set.
*/
if (wq_has_sleeper(&ctx->poll_wq))
io_activate_pollwq(ctx);
}
if (ctx->restrictions.registered)
ctx->restricted = 1;
ctx->flags &= ~IORING_SETUP_R_DISABLED;
if (ctx->sq_data && wq_has_sleeper(&ctx->sq_data->wait))
wake_up(&ctx->sq_data->wait);
return 0;
}
static __cold int __io_register_iowq_aff(struct io_ring_ctx *ctx,
cpumask_var_t new_mask)
{
int ret;
if (!(ctx->flags & IORING_SETUP_SQPOLL)) {
ret = io_wq_cpu_affinity(current->io_uring, new_mask);
} else {
mutex_unlock(&ctx->uring_lock);
ret = io_sqpoll_wq_cpu_affinity(ctx, new_mask);
mutex_lock(&ctx->uring_lock);
}
return ret;
}
static __cold int io_register_iowq_aff(struct io_ring_ctx *ctx,
void __user *arg, unsigned len)
{
cpumask_var_t new_mask;
int ret;
if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
return -ENOMEM;
cpumask_clear(new_mask);
if (len > cpumask_size())
len = cpumask_size();
if (in_compat_syscall()) {
ret = compat_get_bitmap(cpumask_bits(new_mask),
(const compat_ulong_t __user *)arg,
len * 8 /* CHAR_BIT */);
} else {
ret = copy_from_user(new_mask, arg, len);
}
if (ret) {
free_cpumask_var(new_mask);
return -EFAULT;
}
ret = __io_register_iowq_aff(ctx, new_mask);
free_cpumask_var(new_mask);
return ret;
}
static __cold int io_unregister_iowq_aff(struct io_ring_ctx *ctx)
{
return __io_register_iowq_aff(ctx, NULL);
}
static __cold int io_register_iowq_max_workers(struct io_ring_ctx *ctx,
void __user *arg)
__must_hold(&ctx->uring_lock)
{
struct io_tctx_node *node;
struct io_uring_task *tctx = NULL;
struct io_sq_data *sqd = NULL;
__u32 new_count[2];
int i, ret;
if (copy_from_user(new_count, arg, sizeof(new_count)))
return -EFAULT;
for (i = 0; i < ARRAY_SIZE(new_count); i++)
if (new_count[i] > INT_MAX)
return -EINVAL;
if (ctx->flags & IORING_SETUP_SQPOLL) {
sqd = ctx->sq_data;
if (sqd) {
/*
* Observe the correct sqd->lock -> ctx->uring_lock
* ordering. Fine to drop uring_lock here, we hold
* a ref to the ctx.
*/
refcount_inc(&sqd->refs);
mutex_unlock(&ctx->uring_lock);
mutex_lock(&sqd->lock);
mutex_lock(&ctx->uring_lock);
if (sqd->thread)
tctx = sqd->thread->io_uring;
}
} else {
tctx = current->io_uring;
}
BUILD_BUG_ON(sizeof(new_count) != sizeof(ctx->iowq_limits));
for (i = 0; i < ARRAY_SIZE(new_count); i++)
if (new_count[i])
ctx->iowq_limits[i] = new_count[i];
ctx->iowq_limits_set = true;
if (tctx && tctx->io_wq) {
ret = io_wq_max_workers(tctx->io_wq, new_count);
if (ret)
goto err;
} else {
memset(new_count, 0, sizeof(new_count));
}
if (sqd) {
mutex_unlock(&sqd->lock);
io_put_sq_data(sqd);
}
if (copy_to_user(arg, new_count, sizeof(new_count)))
return -EFAULT;
/* that's it for SQPOLL, only the SQPOLL task creates requests */
if (sqd)
return 0;
/* now propagate the restriction to all registered users */
list_for_each_entry(node, &ctx->tctx_list, ctx_node) {
struct io_uring_task *tctx = node->task->io_uring;
if (WARN_ON_ONCE(!tctx->io_wq))
continue;
for (i = 0; i < ARRAY_SIZE(new_count); i++)
new_count[i] = ctx->iowq_limits[i];
/* ignore errors, it always returns zero anyway */
(void)io_wq_max_workers(tctx->io_wq, new_count);
}
return 0;
err:
if (sqd) {
mutex_unlock(&sqd->lock);
io_put_sq_data(sqd);
}
return ret;
}
static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode,
void __user *arg, unsigned nr_args)
__releases(ctx->uring_lock)
__acquires(ctx->uring_lock)
{
int ret;
/*
* We don't quiesce the refs for register anymore and so it can't be
* dying as we're holding a file ref here.
*/
if (WARN_ON_ONCE(percpu_ref_is_dying(&ctx->refs)))
return -ENXIO;
if (ctx->submitter_task && ctx->submitter_task != current)
return -EEXIST;
if (ctx->restricted) {
opcode = array_index_nospec(opcode, IORING_REGISTER_LAST);
if (!test_bit(opcode, ctx->restrictions.register_op))
return -EACCES;
}
switch (opcode) {
case IORING_REGISTER_BUFFERS:
ret = -EFAULT;
if (!arg)
break;
ret = io_sqe_buffers_register(ctx, arg, nr_args, NULL);
break;
case IORING_UNREGISTER_BUFFERS:
ret = -EINVAL;
if (arg || nr_args)
break;
ret = io_sqe_buffers_unregister(ctx);
break;
case IORING_REGISTER_FILES:
ret = -EFAULT;
if (!arg)
break;
ret = io_sqe_files_register(ctx, arg, nr_args, NULL);
break;
case IORING_UNREGISTER_FILES:
ret = -EINVAL;
if (arg || nr_args)
break;
ret = io_sqe_files_unregister(ctx);
break;
case IORING_REGISTER_FILES_UPDATE:
ret = io_register_files_update(ctx, arg, nr_args);
break;
case IORING_REGISTER_EVENTFD:
ret = -EINVAL;
if (nr_args != 1)
break;
ret = io_eventfd_register(ctx, arg, 0);
break;
case IORING_REGISTER_EVENTFD_ASYNC:
ret = -EINVAL;
if (nr_args != 1)
break;
ret = io_eventfd_register(ctx, arg, 1);
break;
case IORING_UNREGISTER_EVENTFD:
ret = -EINVAL;
if (arg || nr_args)
break;
ret = io_eventfd_unregister(ctx);
break;
case IORING_REGISTER_PROBE:
ret = -EINVAL;
if (!arg || nr_args > 256)
break;
ret = io_probe(ctx, arg, nr_args);
break;
case IORING_REGISTER_PERSONALITY:
ret = -EINVAL;
if (arg || nr_args)
break;
ret = io_register_personality(ctx);
break;
case IORING_UNREGISTER_PERSONALITY:
ret = -EINVAL;
if (arg)
break;
ret = io_unregister_personality(ctx, nr_args);
break;
case IORING_REGISTER_ENABLE_RINGS:
ret = -EINVAL;
if (arg || nr_args)
break;
ret = io_register_enable_rings(ctx);
break;
case IORING_REGISTER_RESTRICTIONS:
ret = io_register_restrictions(ctx, arg, nr_args);
break;
case IORING_REGISTER_FILES2:
ret = io_register_rsrc(ctx, arg, nr_args, IORING_RSRC_FILE);
break;
case IORING_REGISTER_FILES_UPDATE2:
ret = io_register_rsrc_update(ctx, arg, nr_args,
IORING_RSRC_FILE);
break;
case IORING_REGISTER_BUFFERS2:
ret = io_register_rsrc(ctx, arg, nr_args, IORING_RSRC_BUFFER);
break;
case IORING_REGISTER_BUFFERS_UPDATE:
ret = io_register_rsrc_update(ctx, arg, nr_args,
IORING_RSRC_BUFFER);
break;
case IORING_REGISTER_IOWQ_AFF:
ret = -EINVAL;
if (!arg || !nr_args)
break;
ret = io_register_iowq_aff(ctx, arg, nr_args);
break;
case IORING_UNREGISTER_IOWQ_AFF:
ret = -EINVAL;
if (arg || nr_args)
break;
ret = io_unregister_iowq_aff(ctx);
break;
case IORING_REGISTER_IOWQ_MAX_WORKERS:
ret = -EINVAL;
if (!arg || nr_args != 2)
break;
ret = io_register_iowq_max_workers(ctx, arg);
break;
case IORING_REGISTER_RING_FDS:
ret = io_ringfd_register(ctx, arg, nr_args);
break;
case IORING_UNREGISTER_RING_FDS:
ret = io_ringfd_unregister(ctx, arg, nr_args);
break;
case IORING_REGISTER_PBUF_RING:
ret = -EINVAL;
if (!arg || nr_args != 1)
break;
ret = io_register_pbuf_ring(ctx, arg);
break;
case IORING_UNREGISTER_PBUF_RING:
ret = -EINVAL;
if (!arg || nr_args != 1)
break;
ret = io_unregister_pbuf_ring(ctx, arg);
break;
case IORING_REGISTER_SYNC_CANCEL:
ret = -EINVAL;
if (!arg || nr_args != 1)
break;
ret = io_sync_cancel(ctx, arg);
break;
case IORING_REGISTER_FILE_ALLOC_RANGE:
ret = -EINVAL;
if (!arg || nr_args)
break;
ret = io_register_file_alloc_range(ctx, arg);
break;
default:
ret = -EINVAL;
break;
}
return ret;
}
SYSCALL_DEFINE4(io_uring_register, unsigned int, fd, unsigned int, opcode,
void __user *, arg, unsigned int, nr_args)
{
struct io_ring_ctx *ctx;
long ret = -EBADF;
struct fd f;
bool use_registered_ring;
use_registered_ring = !!(opcode & IORING_REGISTER_USE_REGISTERED_RING);
opcode &= ~IORING_REGISTER_USE_REGISTERED_RING;
if (opcode >= IORING_REGISTER_LAST)
return -EINVAL;
if (use_registered_ring) {
/*
* Ring fd has been registered via IORING_REGISTER_RING_FDS, we
* need only dereference our task private array to find it.
*/
struct io_uring_task *tctx = current->io_uring;
if (unlikely(!tctx || fd >= IO_RINGFD_REG_MAX))
return -EINVAL;
fd = array_index_nospec(fd, IO_RINGFD_REG_MAX);
f.file = tctx->registered_rings[fd];
f.flags = 0;
if (unlikely(!f.file))
return -EBADF;
} else {
f = fdget(fd);
if (unlikely(!f.file))
return -EBADF;
ret = -EOPNOTSUPP;
if (!io_is_uring_fops(f.file))
goto out_fput;
}
ctx = f.file->private_data;
mutex_lock(&ctx->uring_lock);
ret = __io_uring_register(ctx, opcode, arg, nr_args);
mutex_unlock(&ctx->uring_lock);
trace_io_uring_register(ctx, opcode, ctx->nr_user_files, ctx->nr_user_bufs, ret);
out_fput:
fdput(f);
return ret;
}
static int __init io_uring_init(void)
{
#define __BUILD_BUG_VERIFY_OFFSET_SIZE(stype, eoffset, esize, ename) do { \
BUILD_BUG_ON(offsetof(stype, ename) != eoffset); \
BUILD_BUG_ON(sizeof_field(stype, ename) != esize); \
} while (0)
#define BUILD_BUG_SQE_ELEM(eoffset, etype, ename) \
__BUILD_BUG_VERIFY_OFFSET_SIZE(struct io_uring_sqe, eoffset, sizeof(etype), ename)
#define BUILD_BUG_SQE_ELEM_SIZE(eoffset, esize, ename) \
__BUILD_BUG_VERIFY_OFFSET_SIZE(struct io_uring_sqe, eoffset, esize, ename)
BUILD_BUG_ON(sizeof(struct io_uring_sqe) != 64);
BUILD_BUG_SQE_ELEM(0, __u8, opcode);
BUILD_BUG_SQE_ELEM(1, __u8, flags);
BUILD_BUG_SQE_ELEM(2, __u16, ioprio);
BUILD_BUG_SQE_ELEM(4, __s32, fd);
BUILD_BUG_SQE_ELEM(8, __u64, off);
BUILD_BUG_SQE_ELEM(8, __u64, addr2);
BUILD_BUG_SQE_ELEM(8, __u32, cmd_op);
BUILD_BUG_SQE_ELEM(12, __u32, __pad1);
BUILD_BUG_SQE_ELEM(16, __u64, addr);
BUILD_BUG_SQE_ELEM(16, __u64, splice_off_in);
BUILD_BUG_SQE_ELEM(24, __u32, len);
BUILD_BUG_SQE_ELEM(28, __kernel_rwf_t, rw_flags);
BUILD_BUG_SQE_ELEM(28, /* compat */ int, rw_flags);
BUILD_BUG_SQE_ELEM(28, /* compat */ __u32, rw_flags);
BUILD_BUG_SQE_ELEM(28, __u32, fsync_flags);
BUILD_BUG_SQE_ELEM(28, /* compat */ __u16, poll_events);
BUILD_BUG_SQE_ELEM(28, __u32, poll32_events);
BUILD_BUG_SQE_ELEM(28, __u32, sync_range_flags);
BUILD_BUG_SQE_ELEM(28, __u32, msg_flags);
BUILD_BUG_SQE_ELEM(28, __u32, timeout_flags);
BUILD_BUG_SQE_ELEM(28, __u32, accept_flags);
BUILD_BUG_SQE_ELEM(28, __u32, cancel_flags);
BUILD_BUG_SQE_ELEM(28, __u32, open_flags);
BUILD_BUG_SQE_ELEM(28, __u32, statx_flags);
BUILD_BUG_SQE_ELEM(28, __u32, fadvise_advice);
BUILD_BUG_SQE_ELEM(28, __u32, splice_flags);
BUILD_BUG_SQE_ELEM(28, __u32, rename_flags);
BUILD_BUG_SQE_ELEM(28, __u32, unlink_flags);
BUILD_BUG_SQE_ELEM(28, __u32, hardlink_flags);
BUILD_BUG_SQE_ELEM(28, __u32, xattr_flags);
BUILD_BUG_SQE_ELEM(28, __u32, msg_ring_flags);
BUILD_BUG_SQE_ELEM(32, __u64, user_data);
BUILD_BUG_SQE_ELEM(40, __u16, buf_index);
BUILD_BUG_SQE_ELEM(40, __u16, buf_group);
BUILD_BUG_SQE_ELEM(42, __u16, personality);
BUILD_BUG_SQE_ELEM(44, __s32, splice_fd_in);
BUILD_BUG_SQE_ELEM(44, __u32, file_index);
BUILD_BUG_SQE_ELEM(44, __u16, addr_len);
BUILD_BUG_SQE_ELEM(46, __u16, __pad3[0]);
BUILD_BUG_SQE_ELEM(48, __u64, addr3);
BUILD_BUG_SQE_ELEM_SIZE(48, 0, cmd);
BUILD_BUG_SQE_ELEM(56, __u64, __pad2);
BUILD_BUG_ON(sizeof(struct io_uring_files_update) !=
sizeof(struct io_uring_rsrc_update));
BUILD_BUG_ON(sizeof(struct io_uring_rsrc_update) >
sizeof(struct io_uring_rsrc_update2));
/* ->buf_index is u16 */
BUILD_BUG_ON(offsetof(struct io_uring_buf_ring, bufs) != 0);
BUILD_BUG_ON(offsetof(struct io_uring_buf, resv) !=
offsetof(struct io_uring_buf_ring, tail));
/* should fit into one byte */
BUILD_BUG_ON(SQE_VALID_FLAGS >= (1 << 8));
BUILD_BUG_ON(SQE_COMMON_FLAGS >= (1 << 8));
BUILD_BUG_ON((SQE_VALID_FLAGS | SQE_COMMON_FLAGS) != SQE_VALID_FLAGS);
BUILD_BUG_ON(__REQ_F_LAST_BIT > 8 * sizeof(int));
BUILD_BUG_ON(sizeof(atomic_t) != sizeof(u32));
io_uring_optable_init();
/*
* Allow user copy in the per-command field, which starts after the
* file in io_kiocb and until the opcode field. The openat2 handling
* requires copying in user memory into the io_kiocb object in that
* range, and HARDENED_USERCOPY will complain if we haven't
* correctly annotated this range.
*/
req_cachep = kmem_cache_create_usercopy("io_kiocb",
sizeof(struct io_kiocb), 0,
SLAB_HWCACHE_ALIGN | SLAB_PANIC |
SLAB_ACCOUNT | SLAB_TYPESAFE_BY_RCU,
offsetof(struct io_kiocb, cmd.data),
sizeof_field(struct io_kiocb, cmd.data), NULL);
#ifdef CONFIG_SYSCTL
register_sysctl_init("kernel", kernel_io_uring_disabled_table);
#endif
return 0;
};
__initcall(io_uring_init);
| linux-master | io_uring/io_uring.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/namei.h>
#include <linux/io_uring.h>
#include <linux/splice.h>
#include <uapi/linux/io_uring.h>
#include "io_uring.h"
#include "splice.h"
struct io_splice {
struct file *file_out;
loff_t off_out;
loff_t off_in;
u64 len;
int splice_fd_in;
unsigned int flags;
};
static int __io_splice_prep(struct io_kiocb *req,
const struct io_uring_sqe *sqe)
{
struct io_splice *sp = io_kiocb_to_cmd(req, struct io_splice);
unsigned int valid_flags = SPLICE_F_FD_IN_FIXED | SPLICE_F_ALL;
sp->len = READ_ONCE(sqe->len);
sp->flags = READ_ONCE(sqe->splice_flags);
if (unlikely(sp->flags & ~valid_flags))
return -EINVAL;
sp->splice_fd_in = READ_ONCE(sqe->splice_fd_in);
req->flags |= REQ_F_FORCE_ASYNC;
return 0;
}
int io_tee_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
if (READ_ONCE(sqe->splice_off_in) || READ_ONCE(sqe->off))
return -EINVAL;
return __io_splice_prep(req, sqe);
}
int io_tee(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_splice *sp = io_kiocb_to_cmd(req, struct io_splice);
struct file *out = sp->file_out;
unsigned int flags = sp->flags & ~SPLICE_F_FD_IN_FIXED;
struct file *in;
long ret = 0;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
if (sp->flags & SPLICE_F_FD_IN_FIXED)
in = io_file_get_fixed(req, sp->splice_fd_in, issue_flags);
else
in = io_file_get_normal(req, sp->splice_fd_in);
if (!in) {
ret = -EBADF;
goto done;
}
if (sp->len)
ret = do_tee(in, out, sp->len, flags);
if (!(sp->flags & SPLICE_F_FD_IN_FIXED))
fput(in);
done:
if (ret != sp->len)
req_set_fail(req);
io_req_set_res(req, ret, 0);
return IOU_OK;
}
int io_splice_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_splice *sp = io_kiocb_to_cmd(req, struct io_splice);
sp->off_in = READ_ONCE(sqe->splice_off_in);
sp->off_out = READ_ONCE(sqe->off);
return __io_splice_prep(req, sqe);
}
int io_splice(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_splice *sp = io_kiocb_to_cmd(req, struct io_splice);
struct file *out = sp->file_out;
unsigned int flags = sp->flags & ~SPLICE_F_FD_IN_FIXED;
loff_t *poff_in, *poff_out;
struct file *in;
long ret = 0;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
if (sp->flags & SPLICE_F_FD_IN_FIXED)
in = io_file_get_fixed(req, sp->splice_fd_in, issue_flags);
else
in = io_file_get_normal(req, sp->splice_fd_in);
if (!in) {
ret = -EBADF;
goto done;
}
poff_in = (sp->off_in == -1) ? NULL : &sp->off_in;
poff_out = (sp->off_out == -1) ? NULL : &sp->off_out;
if (sp->len)
ret = do_splice(in, poff_in, out, poff_out, sp->len, flags);
if (!(sp->flags & SPLICE_F_FD_IN_FIXED))
fput(in);
done:
if (ret != sp->len)
req_set_fail(req);
io_req_set_res(req, ret, 0);
return IOU_OK;
}
| linux-master | io_uring/splice.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/namei.h>
#include <linux/io_uring.h>
#include <linux/xattr.h>
#include <uapi/linux/io_uring.h>
#include "../fs/internal.h"
#include "io_uring.h"
#include "xattr.h"
struct io_xattr {
struct file *file;
struct xattr_ctx ctx;
struct filename *filename;
};
void io_xattr_cleanup(struct io_kiocb *req)
{
struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
if (ix->filename)
putname(ix->filename);
kfree(ix->ctx.kname);
kvfree(ix->ctx.kvalue);
}
static void io_xattr_finish(struct io_kiocb *req, int ret)
{
req->flags &= ~REQ_F_NEED_CLEANUP;
io_xattr_cleanup(req);
io_req_set_res(req, ret, 0);
}
static int __io_getxattr_prep(struct io_kiocb *req,
const struct io_uring_sqe *sqe)
{
struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
const char __user *name;
int ret;
if (unlikely(req->flags & REQ_F_FIXED_FILE))
return -EBADF;
ix->filename = NULL;
ix->ctx.kvalue = NULL;
name = u64_to_user_ptr(READ_ONCE(sqe->addr));
ix->ctx.cvalue = u64_to_user_ptr(READ_ONCE(sqe->addr2));
ix->ctx.size = READ_ONCE(sqe->len);
ix->ctx.flags = READ_ONCE(sqe->xattr_flags);
if (ix->ctx.flags)
return -EINVAL;
ix->ctx.kname = kmalloc(sizeof(*ix->ctx.kname), GFP_KERNEL);
if (!ix->ctx.kname)
return -ENOMEM;
ret = strncpy_from_user(ix->ctx.kname->name, name,
sizeof(ix->ctx.kname->name));
if (!ret || ret == sizeof(ix->ctx.kname->name))
ret = -ERANGE;
if (ret < 0) {
kfree(ix->ctx.kname);
return ret;
}
req->flags |= REQ_F_NEED_CLEANUP;
req->flags |= REQ_F_FORCE_ASYNC;
return 0;
}
int io_fgetxattr_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
return __io_getxattr_prep(req, sqe);
}
int io_getxattr_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
const char __user *path;
int ret;
ret = __io_getxattr_prep(req, sqe);
if (ret)
return ret;
path = u64_to_user_ptr(READ_ONCE(sqe->addr3));
ix->filename = getname_flags(path, LOOKUP_FOLLOW, NULL);
if (IS_ERR(ix->filename)) {
ret = PTR_ERR(ix->filename);
ix->filename = NULL;
}
return ret;
}
int io_fgetxattr(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
int ret;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
ret = do_getxattr(mnt_idmap(req->file->f_path.mnt),
req->file->f_path.dentry,
&ix->ctx);
io_xattr_finish(req, ret);
return IOU_OK;
}
int io_getxattr(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
unsigned int lookup_flags = LOOKUP_FOLLOW;
struct path path;
int ret;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
retry:
ret = filename_lookup(AT_FDCWD, ix->filename, lookup_flags, &path, NULL);
if (!ret) {
ret = do_getxattr(mnt_idmap(path.mnt), path.dentry, &ix->ctx);
path_put(&path);
if (retry_estale(ret, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
}
io_xattr_finish(req, ret);
return IOU_OK;
}
static int __io_setxattr_prep(struct io_kiocb *req,
const struct io_uring_sqe *sqe)
{
struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
const char __user *name;
int ret;
if (unlikely(req->flags & REQ_F_FIXED_FILE))
return -EBADF;
ix->filename = NULL;
name = u64_to_user_ptr(READ_ONCE(sqe->addr));
ix->ctx.cvalue = u64_to_user_ptr(READ_ONCE(sqe->addr2));
ix->ctx.kvalue = NULL;
ix->ctx.size = READ_ONCE(sqe->len);
ix->ctx.flags = READ_ONCE(sqe->xattr_flags);
ix->ctx.kname = kmalloc(sizeof(*ix->ctx.kname), GFP_KERNEL);
if (!ix->ctx.kname)
return -ENOMEM;
ret = setxattr_copy(name, &ix->ctx);
if (ret) {
kfree(ix->ctx.kname);
return ret;
}
req->flags |= REQ_F_NEED_CLEANUP;
req->flags |= REQ_F_FORCE_ASYNC;
return 0;
}
int io_setxattr_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
const char __user *path;
int ret;
ret = __io_setxattr_prep(req, sqe);
if (ret)
return ret;
path = u64_to_user_ptr(READ_ONCE(sqe->addr3));
ix->filename = getname_flags(path, LOOKUP_FOLLOW, NULL);
if (IS_ERR(ix->filename)) {
ret = PTR_ERR(ix->filename);
ix->filename = NULL;
}
return ret;
}
int io_fsetxattr_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
return __io_setxattr_prep(req, sqe);
}
static int __io_setxattr(struct io_kiocb *req, unsigned int issue_flags,
const struct path *path)
{
struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
int ret;
ret = mnt_want_write(path->mnt);
if (!ret) {
ret = do_setxattr(mnt_idmap(path->mnt), path->dentry, &ix->ctx);
mnt_drop_write(path->mnt);
}
return ret;
}
int io_fsetxattr(struct io_kiocb *req, unsigned int issue_flags)
{
int ret;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
ret = __io_setxattr(req, issue_flags, &req->file->f_path);
io_xattr_finish(req, ret);
return IOU_OK;
}
int io_setxattr(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
unsigned int lookup_flags = LOOKUP_FOLLOW;
struct path path;
int ret;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
retry:
ret = filename_lookup(AT_FDCWD, ix->filename, lookup_flags, &path, NULL);
if (!ret) {
ret = __io_setxattr(req, issue_flags, &path);
path_put(&path);
if (retry_estale(ret, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
}
io_xattr_finish(req, ret);
return IOU_OK;
}
| linux-master | io_uring/xattr.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/namei.h>
#include <linux/nospec.h>
#include <linux/io_uring.h>
#include <uapi/linux/io_uring.h>
#include "io_uring.h"
#include "tctx.h"
#include "poll.h"
#include "timeout.h"
#include "cancel.h"
struct io_cancel {
struct file *file;
u64 addr;
u32 flags;
s32 fd;
u8 opcode;
};
#define CANCEL_FLAGS (IORING_ASYNC_CANCEL_ALL | IORING_ASYNC_CANCEL_FD | \
IORING_ASYNC_CANCEL_ANY | IORING_ASYNC_CANCEL_FD_FIXED | \
IORING_ASYNC_CANCEL_USERDATA | IORING_ASYNC_CANCEL_OP)
/*
* Returns true if the request matches the criteria outlined by 'cd'.
*/
bool io_cancel_req_match(struct io_kiocb *req, struct io_cancel_data *cd)
{
bool match_user_data = cd->flags & IORING_ASYNC_CANCEL_USERDATA;
if (req->ctx != cd->ctx)
return false;
if (!(cd->flags & (IORING_ASYNC_CANCEL_FD | IORING_ASYNC_CANCEL_OP)))
match_user_data = true;
if (cd->flags & IORING_ASYNC_CANCEL_ANY)
goto check_seq;
if (cd->flags & IORING_ASYNC_CANCEL_FD) {
if (req->file != cd->file)
return false;
}
if (cd->flags & IORING_ASYNC_CANCEL_OP) {
if (req->opcode != cd->opcode)
return false;
}
if (match_user_data && req->cqe.user_data != cd->data)
return false;
if (cd->flags & IORING_ASYNC_CANCEL_ALL) {
check_seq:
if (cd->seq == req->work.cancel_seq)
return false;
req->work.cancel_seq = cd->seq;
}
return true;
}
static bool io_cancel_cb(struct io_wq_work *work, void *data)
{
struct io_kiocb *req = container_of(work, struct io_kiocb, work);
struct io_cancel_data *cd = data;
return io_cancel_req_match(req, cd);
}
static int io_async_cancel_one(struct io_uring_task *tctx,
struct io_cancel_data *cd)
{
enum io_wq_cancel cancel_ret;
int ret = 0;
bool all;
if (!tctx || !tctx->io_wq)
return -ENOENT;
all = cd->flags & (IORING_ASYNC_CANCEL_ALL|IORING_ASYNC_CANCEL_ANY);
cancel_ret = io_wq_cancel_cb(tctx->io_wq, io_cancel_cb, cd, all);
switch (cancel_ret) {
case IO_WQ_CANCEL_OK:
ret = 0;
break;
case IO_WQ_CANCEL_RUNNING:
ret = -EALREADY;
break;
case IO_WQ_CANCEL_NOTFOUND:
ret = -ENOENT;
break;
}
return ret;
}
int io_try_cancel(struct io_uring_task *tctx, struct io_cancel_data *cd,
unsigned issue_flags)
{
struct io_ring_ctx *ctx = cd->ctx;
int ret;
WARN_ON_ONCE(!io_wq_current_is_worker() && tctx != current->io_uring);
ret = io_async_cancel_one(tctx, cd);
/*
* Fall-through even for -EALREADY, as we may have poll armed
* that need unarming.
*/
if (!ret)
return 0;
ret = io_poll_cancel(ctx, cd, issue_flags);
if (ret != -ENOENT)
return ret;
spin_lock(&ctx->completion_lock);
if (!(cd->flags & IORING_ASYNC_CANCEL_FD))
ret = io_timeout_cancel(ctx, cd);
spin_unlock(&ctx->completion_lock);
return ret;
}
int io_async_cancel_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_cancel *cancel = io_kiocb_to_cmd(req, struct io_cancel);
if (unlikely(req->flags & REQ_F_BUFFER_SELECT))
return -EINVAL;
if (sqe->off || sqe->splice_fd_in)
return -EINVAL;
cancel->addr = READ_ONCE(sqe->addr);
cancel->flags = READ_ONCE(sqe->cancel_flags);
if (cancel->flags & ~CANCEL_FLAGS)
return -EINVAL;
if (cancel->flags & IORING_ASYNC_CANCEL_FD) {
if (cancel->flags & IORING_ASYNC_CANCEL_ANY)
return -EINVAL;
cancel->fd = READ_ONCE(sqe->fd);
}
if (cancel->flags & IORING_ASYNC_CANCEL_OP) {
if (cancel->flags & IORING_ASYNC_CANCEL_ANY)
return -EINVAL;
cancel->opcode = READ_ONCE(sqe->len);
}
return 0;
}
static int __io_async_cancel(struct io_cancel_data *cd,
struct io_uring_task *tctx,
unsigned int issue_flags)
{
bool all = cd->flags & (IORING_ASYNC_CANCEL_ALL|IORING_ASYNC_CANCEL_ANY);
struct io_ring_ctx *ctx = cd->ctx;
struct io_tctx_node *node;
int ret, nr = 0;
do {
ret = io_try_cancel(tctx, cd, issue_flags);
if (ret == -ENOENT)
break;
if (!all)
return ret;
nr++;
} while (1);
/* slow path, try all io-wq's */
io_ring_submit_lock(ctx, issue_flags);
ret = -ENOENT;
list_for_each_entry(node, &ctx->tctx_list, ctx_node) {
struct io_uring_task *tctx = node->task->io_uring;
ret = io_async_cancel_one(tctx, cd);
if (ret != -ENOENT) {
if (!all)
break;
nr++;
}
}
io_ring_submit_unlock(ctx, issue_flags);
return all ? nr : ret;
}
int io_async_cancel(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_cancel *cancel = io_kiocb_to_cmd(req, struct io_cancel);
struct io_cancel_data cd = {
.ctx = req->ctx,
.data = cancel->addr,
.flags = cancel->flags,
.opcode = cancel->opcode,
.seq = atomic_inc_return(&req->ctx->cancel_seq),
};
struct io_uring_task *tctx = req->task->io_uring;
int ret;
if (cd.flags & IORING_ASYNC_CANCEL_FD) {
if (req->flags & REQ_F_FIXED_FILE ||
cd.flags & IORING_ASYNC_CANCEL_FD_FIXED) {
req->flags |= REQ_F_FIXED_FILE;
req->file = io_file_get_fixed(req, cancel->fd,
issue_flags);
} else {
req->file = io_file_get_normal(req, cancel->fd);
}
if (!req->file) {
ret = -EBADF;
goto done;
}
cd.file = req->file;
}
ret = __io_async_cancel(&cd, tctx, issue_flags);
done:
if (ret < 0)
req_set_fail(req);
io_req_set_res(req, ret, 0);
return IOU_OK;
}
void init_hash_table(struct io_hash_table *table, unsigned size)
{
unsigned int i;
for (i = 0; i < size; i++) {
spin_lock_init(&table->hbs[i].lock);
INIT_HLIST_HEAD(&table->hbs[i].list);
}
}
static int __io_sync_cancel(struct io_uring_task *tctx,
struct io_cancel_data *cd, int fd)
{
struct io_ring_ctx *ctx = cd->ctx;
/* fixed must be grabbed every time since we drop the uring_lock */
if ((cd->flags & IORING_ASYNC_CANCEL_FD) &&
(cd->flags & IORING_ASYNC_CANCEL_FD_FIXED)) {
if (unlikely(fd >= ctx->nr_user_files))
return -EBADF;
fd = array_index_nospec(fd, ctx->nr_user_files);
cd->file = io_file_from_index(&ctx->file_table, fd);
if (!cd->file)
return -EBADF;
}
return __io_async_cancel(cd, tctx, 0);
}
int io_sync_cancel(struct io_ring_ctx *ctx, void __user *arg)
__must_hold(&ctx->uring_lock)
{
struct io_cancel_data cd = {
.ctx = ctx,
.seq = atomic_inc_return(&ctx->cancel_seq),
};
ktime_t timeout = KTIME_MAX;
struct io_uring_sync_cancel_reg sc;
struct fd f = { };
DEFINE_WAIT(wait);
int ret, i;
if (copy_from_user(&sc, arg, sizeof(sc)))
return -EFAULT;
if (sc.flags & ~CANCEL_FLAGS)
return -EINVAL;
for (i = 0; i < ARRAY_SIZE(sc.pad); i++)
if (sc.pad[i])
return -EINVAL;
for (i = 0; i < ARRAY_SIZE(sc.pad2); i++)
if (sc.pad2[i])
return -EINVAL;
cd.data = sc.addr;
cd.flags = sc.flags;
cd.opcode = sc.opcode;
/* we can grab a normal file descriptor upfront */
if ((cd.flags & IORING_ASYNC_CANCEL_FD) &&
!(cd.flags & IORING_ASYNC_CANCEL_FD_FIXED)) {
f = fdget(sc.fd);
if (!f.file)
return -EBADF;
cd.file = f.file;
}
ret = __io_sync_cancel(current->io_uring, &cd, sc.fd);
/* found something, done! */
if (ret != -EALREADY)
goto out;
if (sc.timeout.tv_sec != -1UL || sc.timeout.tv_nsec != -1UL) {
struct timespec64 ts = {
.tv_sec = sc.timeout.tv_sec,
.tv_nsec = sc.timeout.tv_nsec
};
timeout = ktime_add_ns(timespec64_to_ktime(ts), ktime_get_ns());
}
/*
* Keep looking until we get -ENOENT. we'll get woken everytime
* every time a request completes and will retry the cancelation.
*/
do {
cd.seq = atomic_inc_return(&ctx->cancel_seq);
prepare_to_wait(&ctx->cq_wait, &wait, TASK_INTERRUPTIBLE);
ret = __io_sync_cancel(current->io_uring, &cd, sc.fd);
mutex_unlock(&ctx->uring_lock);
if (ret != -EALREADY)
break;
ret = io_run_task_work_sig(ctx);
if (ret < 0)
break;
ret = schedule_hrtimeout(&timeout, HRTIMER_MODE_ABS);
if (!ret) {
ret = -ETIME;
break;
}
mutex_lock(&ctx->uring_lock);
} while (1);
finish_wait(&ctx->cq_wait, &wait);
mutex_lock(&ctx->uring_lock);
if (ret == -ENOENT || ret > 0)
ret = 0;
out:
fdput(f);
return ret;
}
| linux-master | io_uring/cancel.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/file.h>
#include <linux/io_uring.h>
#include <trace/events/io_uring.h>
#include <uapi/linux/io_uring.h>
#include "io_uring.h"
#include "refs.h"
#include "cancel.h"
#include "timeout.h"
struct io_timeout {
struct file *file;
u32 off;
u32 target_seq;
u32 repeats;
struct list_head list;
/* head of the link, used by linked timeouts only */
struct io_kiocb *head;
/* for linked completions */
struct io_kiocb *prev;
};
struct io_timeout_rem {
struct file *file;
u64 addr;
/* timeout update */
struct timespec64 ts;
u32 flags;
bool ltimeout;
};
static inline bool io_is_timeout_noseq(struct io_kiocb *req)
{
struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
struct io_timeout_data *data = req->async_data;
return !timeout->off || data->flags & IORING_TIMEOUT_MULTISHOT;
}
static inline void io_put_req(struct io_kiocb *req)
{
if (req_ref_put_and_test(req)) {
io_queue_next(req);
io_free_req(req);
}
}
static inline bool io_timeout_finish(struct io_timeout *timeout,
struct io_timeout_data *data)
{
if (!(data->flags & IORING_TIMEOUT_MULTISHOT))
return true;
if (!timeout->off || (timeout->repeats && --timeout->repeats))
return false;
return true;
}
static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer);
static void io_timeout_complete(struct io_kiocb *req, struct io_tw_state *ts)
{
struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
struct io_timeout_data *data = req->async_data;
struct io_ring_ctx *ctx = req->ctx;
if (!io_timeout_finish(timeout, data)) {
bool filled;
filled = io_fill_cqe_req_aux(req, ts->locked, -ETIME,
IORING_CQE_F_MORE);
if (filled) {
/* re-arm timer */
spin_lock_irq(&ctx->timeout_lock);
list_add(&timeout->list, ctx->timeout_list.prev);
data->timer.function = io_timeout_fn;
hrtimer_start(&data->timer, timespec64_to_ktime(data->ts), data->mode);
spin_unlock_irq(&ctx->timeout_lock);
return;
}
}
io_req_task_complete(req, ts);
}
static bool io_kill_timeout(struct io_kiocb *req, int status)
__must_hold(&req->ctx->timeout_lock)
{
struct io_timeout_data *io = req->async_data;
if (hrtimer_try_to_cancel(&io->timer) != -1) {
struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
if (status)
req_set_fail(req);
atomic_set(&req->ctx->cq_timeouts,
atomic_read(&req->ctx->cq_timeouts) + 1);
list_del_init(&timeout->list);
io_req_queue_tw_complete(req, status);
return true;
}
return false;
}
__cold void io_flush_timeouts(struct io_ring_ctx *ctx)
{
u32 seq;
struct io_timeout *timeout, *tmp;
spin_lock_irq(&ctx->timeout_lock);
seq = ctx->cached_cq_tail - atomic_read(&ctx->cq_timeouts);
list_for_each_entry_safe(timeout, tmp, &ctx->timeout_list, list) {
struct io_kiocb *req = cmd_to_io_kiocb(timeout);
u32 events_needed, events_got;
if (io_is_timeout_noseq(req))
break;
/*
* Since seq can easily wrap around over time, subtract
* the last seq at which timeouts were flushed before comparing.
* Assuming not more than 2^31-1 events have happened since,
* these subtractions won't have wrapped, so we can check if
* target is in [last_seq, current_seq] by comparing the two.
*/
events_needed = timeout->target_seq - ctx->cq_last_tm_flush;
events_got = seq - ctx->cq_last_tm_flush;
if (events_got < events_needed)
break;
io_kill_timeout(req, 0);
}
ctx->cq_last_tm_flush = seq;
spin_unlock_irq(&ctx->timeout_lock);
}
static void io_req_tw_fail_links(struct io_kiocb *link, struct io_tw_state *ts)
{
io_tw_lock(link->ctx, ts);
while (link) {
struct io_kiocb *nxt = link->link;
long res = -ECANCELED;
if (link->flags & REQ_F_FAIL)
res = link->cqe.res;
link->link = NULL;
io_req_set_res(link, res, 0);
io_req_task_complete(link, ts);
link = nxt;
}
}
static void io_fail_links(struct io_kiocb *req)
__must_hold(&req->ctx->completion_lock)
{
struct io_kiocb *link = req->link;
bool ignore_cqes = req->flags & REQ_F_SKIP_LINK_CQES;
if (!link)
return;
while (link) {
if (ignore_cqes)
link->flags |= REQ_F_CQE_SKIP;
else
link->flags &= ~REQ_F_CQE_SKIP;
trace_io_uring_fail_link(req, link);
link = link->link;
}
link = req->link;
link->io_task_work.func = io_req_tw_fail_links;
io_req_task_work_add(link);
req->link = NULL;
}
static inline void io_remove_next_linked(struct io_kiocb *req)
{
struct io_kiocb *nxt = req->link;
req->link = nxt->link;
nxt->link = NULL;
}
void io_disarm_next(struct io_kiocb *req)
__must_hold(&req->ctx->completion_lock)
{
struct io_kiocb *link = NULL;
if (req->flags & REQ_F_ARM_LTIMEOUT) {
link = req->link;
req->flags &= ~REQ_F_ARM_LTIMEOUT;
if (link && link->opcode == IORING_OP_LINK_TIMEOUT) {
io_remove_next_linked(req);
io_req_queue_tw_complete(link, -ECANCELED);
}
} else if (req->flags & REQ_F_LINK_TIMEOUT) {
struct io_ring_ctx *ctx = req->ctx;
spin_lock_irq(&ctx->timeout_lock);
link = io_disarm_linked_timeout(req);
spin_unlock_irq(&ctx->timeout_lock);
if (link)
io_req_queue_tw_complete(link, -ECANCELED);
}
if (unlikely((req->flags & REQ_F_FAIL) &&
!(req->flags & REQ_F_HARDLINK)))
io_fail_links(req);
}
struct io_kiocb *__io_disarm_linked_timeout(struct io_kiocb *req,
struct io_kiocb *link)
__must_hold(&req->ctx->completion_lock)
__must_hold(&req->ctx->timeout_lock)
{
struct io_timeout_data *io = link->async_data;
struct io_timeout *timeout = io_kiocb_to_cmd(link, struct io_timeout);
io_remove_next_linked(req);
timeout->head = NULL;
if (hrtimer_try_to_cancel(&io->timer) != -1) {
list_del(&timeout->list);
return link;
}
return NULL;
}
static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer)
{
struct io_timeout_data *data = container_of(timer,
struct io_timeout_data, timer);
struct io_kiocb *req = data->req;
struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
struct io_ring_ctx *ctx = req->ctx;
unsigned long flags;
spin_lock_irqsave(&ctx->timeout_lock, flags);
list_del_init(&timeout->list);
atomic_set(&req->ctx->cq_timeouts,
atomic_read(&req->ctx->cq_timeouts) + 1);
spin_unlock_irqrestore(&ctx->timeout_lock, flags);
if (!(data->flags & IORING_TIMEOUT_ETIME_SUCCESS))
req_set_fail(req);
io_req_set_res(req, -ETIME, 0);
req->io_task_work.func = io_timeout_complete;
io_req_task_work_add(req);
return HRTIMER_NORESTART;
}
static struct io_kiocb *io_timeout_extract(struct io_ring_ctx *ctx,
struct io_cancel_data *cd)
__must_hold(&ctx->timeout_lock)
{
struct io_timeout *timeout;
struct io_timeout_data *io;
struct io_kiocb *req = NULL;
list_for_each_entry(timeout, &ctx->timeout_list, list) {
struct io_kiocb *tmp = cmd_to_io_kiocb(timeout);
if (io_cancel_req_match(tmp, cd)) {
req = tmp;
break;
}
}
if (!req)
return ERR_PTR(-ENOENT);
io = req->async_data;
if (hrtimer_try_to_cancel(&io->timer) == -1)
return ERR_PTR(-EALREADY);
timeout = io_kiocb_to_cmd(req, struct io_timeout);
list_del_init(&timeout->list);
return req;
}
int io_timeout_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd)
__must_hold(&ctx->completion_lock)
{
struct io_kiocb *req;
spin_lock_irq(&ctx->timeout_lock);
req = io_timeout_extract(ctx, cd);
spin_unlock_irq(&ctx->timeout_lock);
if (IS_ERR(req))
return PTR_ERR(req);
io_req_task_queue_fail(req, -ECANCELED);
return 0;
}
static void io_req_task_link_timeout(struct io_kiocb *req, struct io_tw_state *ts)
{
unsigned issue_flags = ts->locked ? 0 : IO_URING_F_UNLOCKED;
struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
struct io_kiocb *prev = timeout->prev;
int ret = -ENOENT;
if (prev) {
if (!(req->task->flags & PF_EXITING)) {
struct io_cancel_data cd = {
.ctx = req->ctx,
.data = prev->cqe.user_data,
};
ret = io_try_cancel(req->task->io_uring, &cd, issue_flags);
}
io_req_set_res(req, ret ?: -ETIME, 0);
io_req_task_complete(req, ts);
io_put_req(prev);
} else {
io_req_set_res(req, -ETIME, 0);
io_req_task_complete(req, ts);
}
}
static enum hrtimer_restart io_link_timeout_fn(struct hrtimer *timer)
{
struct io_timeout_data *data = container_of(timer,
struct io_timeout_data, timer);
struct io_kiocb *prev, *req = data->req;
struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
struct io_ring_ctx *ctx = req->ctx;
unsigned long flags;
spin_lock_irqsave(&ctx->timeout_lock, flags);
prev = timeout->head;
timeout->head = NULL;
/*
* We don't expect the list to be empty, that will only happen if we
* race with the completion of the linked work.
*/
if (prev) {
io_remove_next_linked(prev);
if (!req_ref_inc_not_zero(prev))
prev = NULL;
}
list_del(&timeout->list);
timeout->prev = prev;
spin_unlock_irqrestore(&ctx->timeout_lock, flags);
req->io_task_work.func = io_req_task_link_timeout;
io_req_task_work_add(req);
return HRTIMER_NORESTART;
}
static clockid_t io_timeout_get_clock(struct io_timeout_data *data)
{
switch (data->flags & IORING_TIMEOUT_CLOCK_MASK) {
case IORING_TIMEOUT_BOOTTIME:
return CLOCK_BOOTTIME;
case IORING_TIMEOUT_REALTIME:
return CLOCK_REALTIME;
default:
/* can't happen, vetted at prep time */
WARN_ON_ONCE(1);
fallthrough;
case 0:
return CLOCK_MONOTONIC;
}
}
static int io_linked_timeout_update(struct io_ring_ctx *ctx, __u64 user_data,
struct timespec64 *ts, enum hrtimer_mode mode)
__must_hold(&ctx->timeout_lock)
{
struct io_timeout_data *io;
struct io_timeout *timeout;
struct io_kiocb *req = NULL;
list_for_each_entry(timeout, &ctx->ltimeout_list, list) {
struct io_kiocb *tmp = cmd_to_io_kiocb(timeout);
if (user_data == tmp->cqe.user_data) {
req = tmp;
break;
}
}
if (!req)
return -ENOENT;
io = req->async_data;
if (hrtimer_try_to_cancel(&io->timer) == -1)
return -EALREADY;
hrtimer_init(&io->timer, io_timeout_get_clock(io), mode);
io->timer.function = io_link_timeout_fn;
hrtimer_start(&io->timer, timespec64_to_ktime(*ts), mode);
return 0;
}
static int io_timeout_update(struct io_ring_ctx *ctx, __u64 user_data,
struct timespec64 *ts, enum hrtimer_mode mode)
__must_hold(&ctx->timeout_lock)
{
struct io_cancel_data cd = { .ctx = ctx, .data = user_data, };
struct io_kiocb *req = io_timeout_extract(ctx, &cd);
struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
struct io_timeout_data *data;
if (IS_ERR(req))
return PTR_ERR(req);
timeout->off = 0; /* noseq */
data = req->async_data;
list_add_tail(&timeout->list, &ctx->timeout_list);
hrtimer_init(&data->timer, io_timeout_get_clock(data), mode);
data->timer.function = io_timeout_fn;
hrtimer_start(&data->timer, timespec64_to_ktime(*ts), mode);
return 0;
}
int io_timeout_remove_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_timeout_rem *tr = io_kiocb_to_cmd(req, struct io_timeout_rem);
if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
return -EINVAL;
if (sqe->buf_index || sqe->len || sqe->splice_fd_in)
return -EINVAL;
tr->ltimeout = false;
tr->addr = READ_ONCE(sqe->addr);
tr->flags = READ_ONCE(sqe->timeout_flags);
if (tr->flags & IORING_TIMEOUT_UPDATE_MASK) {
if (hweight32(tr->flags & IORING_TIMEOUT_CLOCK_MASK) > 1)
return -EINVAL;
if (tr->flags & IORING_LINK_TIMEOUT_UPDATE)
tr->ltimeout = true;
if (tr->flags & ~(IORING_TIMEOUT_UPDATE_MASK|IORING_TIMEOUT_ABS))
return -EINVAL;
if (get_timespec64(&tr->ts, u64_to_user_ptr(sqe->addr2)))
return -EFAULT;
if (tr->ts.tv_sec < 0 || tr->ts.tv_nsec < 0)
return -EINVAL;
} else if (tr->flags) {
/* timeout removal doesn't support flags */
return -EINVAL;
}
return 0;
}
static inline enum hrtimer_mode io_translate_timeout_mode(unsigned int flags)
{
return (flags & IORING_TIMEOUT_ABS) ? HRTIMER_MODE_ABS
: HRTIMER_MODE_REL;
}
/*
* Remove or update an existing timeout command
*/
int io_timeout_remove(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_timeout_rem *tr = io_kiocb_to_cmd(req, struct io_timeout_rem);
struct io_ring_ctx *ctx = req->ctx;
int ret;
if (!(tr->flags & IORING_TIMEOUT_UPDATE)) {
struct io_cancel_data cd = { .ctx = ctx, .data = tr->addr, };
spin_lock(&ctx->completion_lock);
ret = io_timeout_cancel(ctx, &cd);
spin_unlock(&ctx->completion_lock);
} else {
enum hrtimer_mode mode = io_translate_timeout_mode(tr->flags);
spin_lock_irq(&ctx->timeout_lock);
if (tr->ltimeout)
ret = io_linked_timeout_update(ctx, tr->addr, &tr->ts, mode);
else
ret = io_timeout_update(ctx, tr->addr, &tr->ts, mode);
spin_unlock_irq(&ctx->timeout_lock);
}
if (ret < 0)
req_set_fail(req);
io_req_set_res(req, ret, 0);
return IOU_OK;
}
static int __io_timeout_prep(struct io_kiocb *req,
const struct io_uring_sqe *sqe,
bool is_timeout_link)
{
struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
struct io_timeout_data *data;
unsigned flags;
u32 off = READ_ONCE(sqe->off);
if (sqe->buf_index || sqe->len != 1 || sqe->splice_fd_in)
return -EINVAL;
if (off && is_timeout_link)
return -EINVAL;
flags = READ_ONCE(sqe->timeout_flags);
if (flags & ~(IORING_TIMEOUT_ABS | IORING_TIMEOUT_CLOCK_MASK |
IORING_TIMEOUT_ETIME_SUCCESS |
IORING_TIMEOUT_MULTISHOT))
return -EINVAL;
/* more than one clock specified is invalid, obviously */
if (hweight32(flags & IORING_TIMEOUT_CLOCK_MASK) > 1)
return -EINVAL;
/* multishot requests only make sense with rel values */
if (!(~flags & (IORING_TIMEOUT_MULTISHOT | IORING_TIMEOUT_ABS)))
return -EINVAL;
INIT_LIST_HEAD(&timeout->list);
timeout->off = off;
if (unlikely(off && !req->ctx->off_timeout_used))
req->ctx->off_timeout_used = true;
/*
* for multishot reqs w/ fixed nr of repeats, repeats tracks the
* remaining nr
*/
timeout->repeats = 0;
if ((flags & IORING_TIMEOUT_MULTISHOT) && off > 0)
timeout->repeats = off;
if (WARN_ON_ONCE(req_has_async_data(req)))
return -EFAULT;
if (io_alloc_async_data(req))
return -ENOMEM;
data = req->async_data;
data->req = req;
data->flags = flags;
if (get_timespec64(&data->ts, u64_to_user_ptr(sqe->addr)))
return -EFAULT;
if (data->ts.tv_sec < 0 || data->ts.tv_nsec < 0)
return -EINVAL;
INIT_LIST_HEAD(&timeout->list);
data->mode = io_translate_timeout_mode(flags);
hrtimer_init(&data->timer, io_timeout_get_clock(data), data->mode);
if (is_timeout_link) {
struct io_submit_link *link = &req->ctx->submit_state.link;
if (!link->head)
return -EINVAL;
if (link->last->opcode == IORING_OP_LINK_TIMEOUT)
return -EINVAL;
timeout->head = link->last;
link->last->flags |= REQ_F_ARM_LTIMEOUT;
}
return 0;
}
int io_timeout_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
return __io_timeout_prep(req, sqe, false);
}
int io_link_timeout_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
return __io_timeout_prep(req, sqe, true);
}
int io_timeout(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
struct io_ring_ctx *ctx = req->ctx;
struct io_timeout_data *data = req->async_data;
struct list_head *entry;
u32 tail, off = timeout->off;
spin_lock_irq(&ctx->timeout_lock);
/*
* sqe->off holds how many events that need to occur for this
* timeout event to be satisfied. If it isn't set, then this is
* a pure timeout request, sequence isn't used.
*/
if (io_is_timeout_noseq(req)) {
entry = ctx->timeout_list.prev;
goto add;
}
tail = data_race(ctx->cached_cq_tail) - atomic_read(&ctx->cq_timeouts);
timeout->target_seq = tail + off;
/* Update the last seq here in case io_flush_timeouts() hasn't.
* This is safe because ->completion_lock is held, and submissions
* and completions are never mixed in the same ->completion_lock section.
*/
ctx->cq_last_tm_flush = tail;
/*
* Insertion sort, ensuring the first entry in the list is always
* the one we need first.
*/
list_for_each_prev(entry, &ctx->timeout_list) {
struct io_timeout *nextt = list_entry(entry, struct io_timeout, list);
struct io_kiocb *nxt = cmd_to_io_kiocb(nextt);
if (io_is_timeout_noseq(nxt))
continue;
/* nxt.seq is behind @tail, otherwise would've been completed */
if (off >= nextt->target_seq - tail)
break;
}
add:
list_add(&timeout->list, entry);
data->timer.function = io_timeout_fn;
hrtimer_start(&data->timer, timespec64_to_ktime(data->ts), data->mode);
spin_unlock_irq(&ctx->timeout_lock);
return IOU_ISSUE_SKIP_COMPLETE;
}
void io_queue_linked_timeout(struct io_kiocb *req)
{
struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
struct io_ring_ctx *ctx = req->ctx;
spin_lock_irq(&ctx->timeout_lock);
/*
* If the back reference is NULL, then our linked request finished
* before we got a chance to setup the timer
*/
if (timeout->head) {
struct io_timeout_data *data = req->async_data;
data->timer.function = io_link_timeout_fn;
hrtimer_start(&data->timer, timespec64_to_ktime(data->ts),
data->mode);
list_add_tail(&timeout->list, &ctx->ltimeout_list);
}
spin_unlock_irq(&ctx->timeout_lock);
/* drop submission reference */
io_put_req(req);
}
static bool io_match_task(struct io_kiocb *head, struct task_struct *task,
bool cancel_all)
__must_hold(&req->ctx->timeout_lock)
{
struct io_kiocb *req;
if (task && head->task != task)
return false;
if (cancel_all)
return true;
io_for_each_link(req, head) {
if (req->flags & REQ_F_INFLIGHT)
return true;
}
return false;
}
/* Returns true if we found and killed one or more timeouts */
__cold bool io_kill_timeouts(struct io_ring_ctx *ctx, struct task_struct *tsk,
bool cancel_all)
{
struct io_timeout *timeout, *tmp;
int canceled = 0;
/*
* completion_lock is needed for io_match_task(). Take it before
* timeout_lockfirst to keep locking ordering.
*/
spin_lock(&ctx->completion_lock);
spin_lock_irq(&ctx->timeout_lock);
list_for_each_entry_safe(timeout, tmp, &ctx->timeout_list, list) {
struct io_kiocb *req = cmd_to_io_kiocb(timeout);
if (io_match_task(req, tsk, cancel_all) &&
io_kill_timeout(req, -ECANCELED))
canceled++;
}
spin_unlock_irq(&ctx->timeout_lock);
spin_unlock(&ctx->completion_lock);
return canceled != 0;
}
| linux-master | io_uring/timeout.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/namei.h>
#include <linux/poll.h>
#include <linux/io_uring.h>
#include <uapi/linux/io_uring.h>
#include "io_uring.h"
#include "opdef.h"
#include "kbuf.h"
#define IO_BUFFER_LIST_BUF_PER_PAGE (PAGE_SIZE / sizeof(struct io_uring_buf))
#define BGID_ARRAY 64
struct io_provide_buf {
struct file *file;
__u64 addr;
__u32 len;
__u32 bgid;
__u16 nbufs;
__u16 bid;
};
static inline struct io_buffer_list *io_buffer_get_list(struct io_ring_ctx *ctx,
unsigned int bgid)
{
if (ctx->io_bl && bgid < BGID_ARRAY)
return &ctx->io_bl[bgid];
return xa_load(&ctx->io_bl_xa, bgid);
}
static int io_buffer_add_list(struct io_ring_ctx *ctx,
struct io_buffer_list *bl, unsigned int bgid)
{
bl->bgid = bgid;
if (bgid < BGID_ARRAY)
return 0;
return xa_err(xa_store(&ctx->io_bl_xa, bgid, bl, GFP_KERNEL));
}
void io_kbuf_recycle_legacy(struct io_kiocb *req, unsigned issue_flags)
{
struct io_ring_ctx *ctx = req->ctx;
struct io_buffer_list *bl;
struct io_buffer *buf;
/*
* For legacy provided buffer mode, don't recycle if we already did
* IO to this buffer. For ring-mapped provided buffer mode, we should
* increment ring->head to explicitly monopolize the buffer to avoid
* multiple use.
*/
if (req->flags & REQ_F_PARTIAL_IO)
return;
io_ring_submit_lock(ctx, issue_flags);
buf = req->kbuf;
bl = io_buffer_get_list(ctx, buf->bgid);
list_add(&buf->list, &bl->buf_list);
req->flags &= ~REQ_F_BUFFER_SELECTED;
req->buf_index = buf->bgid;
io_ring_submit_unlock(ctx, issue_flags);
return;
}
unsigned int __io_put_kbuf(struct io_kiocb *req, unsigned issue_flags)
{
unsigned int cflags;
/*
* We can add this buffer back to two lists:
*
* 1) The io_buffers_cache list. This one is protected by the
* ctx->uring_lock. If we already hold this lock, add back to this
* list as we can grab it from issue as well.
* 2) The io_buffers_comp list. This one is protected by the
* ctx->completion_lock.
*
* We migrate buffers from the comp_list to the issue cache list
* when we need one.
*/
if (req->flags & REQ_F_BUFFER_RING) {
/* no buffers to recycle for this case */
cflags = __io_put_kbuf_list(req, NULL);
} else if (issue_flags & IO_URING_F_UNLOCKED) {
struct io_ring_ctx *ctx = req->ctx;
spin_lock(&ctx->completion_lock);
cflags = __io_put_kbuf_list(req, &ctx->io_buffers_comp);
spin_unlock(&ctx->completion_lock);
} else {
lockdep_assert_held(&req->ctx->uring_lock);
cflags = __io_put_kbuf_list(req, &req->ctx->io_buffers_cache);
}
return cflags;
}
static void __user *io_provided_buffer_select(struct io_kiocb *req, size_t *len,
struct io_buffer_list *bl)
{
if (!list_empty(&bl->buf_list)) {
struct io_buffer *kbuf;
kbuf = list_first_entry(&bl->buf_list, struct io_buffer, list);
list_del(&kbuf->list);
if (*len == 0 || *len > kbuf->len)
*len = kbuf->len;
req->flags |= REQ_F_BUFFER_SELECTED;
req->kbuf = kbuf;
req->buf_index = kbuf->bid;
return u64_to_user_ptr(kbuf->addr);
}
return NULL;
}
static void __user *io_ring_buffer_select(struct io_kiocb *req, size_t *len,
struct io_buffer_list *bl,
unsigned int issue_flags)
{
struct io_uring_buf_ring *br = bl->buf_ring;
struct io_uring_buf *buf;
__u16 head = bl->head;
if (unlikely(smp_load_acquire(&br->tail) == head))
return NULL;
head &= bl->mask;
/* mmaped buffers are always contig */
if (bl->is_mmap || head < IO_BUFFER_LIST_BUF_PER_PAGE) {
buf = &br->bufs[head];
} else {
int off = head & (IO_BUFFER_LIST_BUF_PER_PAGE - 1);
int index = head / IO_BUFFER_LIST_BUF_PER_PAGE;
buf = page_address(bl->buf_pages[index]);
buf += off;
}
if (*len == 0 || *len > buf->len)
*len = buf->len;
req->flags |= REQ_F_BUFFER_RING;
req->buf_list = bl;
req->buf_index = buf->bid;
if (issue_flags & IO_URING_F_UNLOCKED || !file_can_poll(req->file)) {
/*
* If we came in unlocked, we have no choice but to consume the
* buffer here, otherwise nothing ensures that the buffer won't
* get used by others. This does mean it'll be pinned until the
* IO completes, coming in unlocked means we're being called from
* io-wq context and there may be further retries in async hybrid
* mode. For the locked case, the caller must call commit when
* the transfer completes (or if we get -EAGAIN and must poll of
* retry).
*/
req->buf_list = NULL;
bl->head++;
}
return u64_to_user_ptr(buf->addr);
}
void __user *io_buffer_select(struct io_kiocb *req, size_t *len,
unsigned int issue_flags)
{
struct io_ring_ctx *ctx = req->ctx;
struct io_buffer_list *bl;
void __user *ret = NULL;
io_ring_submit_lock(req->ctx, issue_flags);
bl = io_buffer_get_list(ctx, req->buf_index);
if (likely(bl)) {
if (bl->is_mapped)
ret = io_ring_buffer_select(req, len, bl, issue_flags);
else
ret = io_provided_buffer_select(req, len, bl);
}
io_ring_submit_unlock(req->ctx, issue_flags);
return ret;
}
static __cold int io_init_bl_list(struct io_ring_ctx *ctx)
{
int i;
ctx->io_bl = kcalloc(BGID_ARRAY, sizeof(struct io_buffer_list),
GFP_KERNEL);
if (!ctx->io_bl)
return -ENOMEM;
for (i = 0; i < BGID_ARRAY; i++) {
INIT_LIST_HEAD(&ctx->io_bl[i].buf_list);
ctx->io_bl[i].bgid = i;
}
return 0;
}
static int __io_remove_buffers(struct io_ring_ctx *ctx,
struct io_buffer_list *bl, unsigned nbufs)
{
unsigned i = 0;
/* shouldn't happen */
if (!nbufs)
return 0;
if (bl->is_mapped) {
i = bl->buf_ring->tail - bl->head;
if (bl->is_mmap) {
folio_put(virt_to_folio(bl->buf_ring));
bl->buf_ring = NULL;
bl->is_mmap = 0;
} else if (bl->buf_nr_pages) {
int j;
for (j = 0; j < bl->buf_nr_pages; j++)
unpin_user_page(bl->buf_pages[j]);
kvfree(bl->buf_pages);
bl->buf_pages = NULL;
bl->buf_nr_pages = 0;
}
/* make sure it's seen as empty */
INIT_LIST_HEAD(&bl->buf_list);
bl->is_mapped = 0;
return i;
}
/* protects io_buffers_cache */
lockdep_assert_held(&ctx->uring_lock);
while (!list_empty(&bl->buf_list)) {
struct io_buffer *nxt;
nxt = list_first_entry(&bl->buf_list, struct io_buffer, list);
list_move(&nxt->list, &ctx->io_buffers_cache);
if (++i == nbufs)
return i;
cond_resched();
}
return i;
}
void io_destroy_buffers(struct io_ring_ctx *ctx)
{
struct io_buffer_list *bl;
unsigned long index;
int i;
for (i = 0; i < BGID_ARRAY; i++) {
if (!ctx->io_bl)
break;
__io_remove_buffers(ctx, &ctx->io_bl[i], -1U);
}
xa_for_each(&ctx->io_bl_xa, index, bl) {
xa_erase(&ctx->io_bl_xa, bl->bgid);
__io_remove_buffers(ctx, bl, -1U);
kfree(bl);
}
while (!list_empty(&ctx->io_buffers_pages)) {
struct page *page;
page = list_first_entry(&ctx->io_buffers_pages, struct page, lru);
list_del_init(&page->lru);
__free_page(page);
}
}
int io_remove_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_provide_buf *p = io_kiocb_to_cmd(req, struct io_provide_buf);
u64 tmp;
if (sqe->rw_flags || sqe->addr || sqe->len || sqe->off ||
sqe->splice_fd_in)
return -EINVAL;
tmp = READ_ONCE(sqe->fd);
if (!tmp || tmp > USHRT_MAX)
return -EINVAL;
memset(p, 0, sizeof(*p));
p->nbufs = tmp;
p->bgid = READ_ONCE(sqe->buf_group);
return 0;
}
int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_provide_buf *p = io_kiocb_to_cmd(req, struct io_provide_buf);
struct io_ring_ctx *ctx = req->ctx;
struct io_buffer_list *bl;
int ret = 0;
io_ring_submit_lock(ctx, issue_flags);
ret = -ENOENT;
bl = io_buffer_get_list(ctx, p->bgid);
if (bl) {
ret = -EINVAL;
/* can't use provide/remove buffers command on mapped buffers */
if (!bl->is_mapped)
ret = __io_remove_buffers(ctx, bl, p->nbufs);
}
io_ring_submit_unlock(ctx, issue_flags);
if (ret < 0)
req_set_fail(req);
io_req_set_res(req, ret, 0);
return IOU_OK;
}
int io_provide_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
unsigned long size, tmp_check;
struct io_provide_buf *p = io_kiocb_to_cmd(req, struct io_provide_buf);
u64 tmp;
if (sqe->rw_flags || sqe->splice_fd_in)
return -EINVAL;
tmp = READ_ONCE(sqe->fd);
if (!tmp || tmp > USHRT_MAX)
return -E2BIG;
p->nbufs = tmp;
p->addr = READ_ONCE(sqe->addr);
p->len = READ_ONCE(sqe->len);
if (check_mul_overflow((unsigned long)p->len, (unsigned long)p->nbufs,
&size))
return -EOVERFLOW;
if (check_add_overflow((unsigned long)p->addr, size, &tmp_check))
return -EOVERFLOW;
size = (unsigned long)p->len * p->nbufs;
if (!access_ok(u64_to_user_ptr(p->addr), size))
return -EFAULT;
p->bgid = READ_ONCE(sqe->buf_group);
tmp = READ_ONCE(sqe->off);
if (tmp > USHRT_MAX)
return -E2BIG;
if (tmp + p->nbufs >= USHRT_MAX)
return -EINVAL;
p->bid = tmp;
return 0;
}
static int io_refill_buffer_cache(struct io_ring_ctx *ctx)
{
struct io_buffer *buf;
struct page *page;
int bufs_in_page;
/*
* Completions that don't happen inline (eg not under uring_lock) will
* add to ->io_buffers_comp. If we don't have any free buffers, check
* the completion list and splice those entries first.
*/
if (!list_empty_careful(&ctx->io_buffers_comp)) {
spin_lock(&ctx->completion_lock);
if (!list_empty(&ctx->io_buffers_comp)) {
list_splice_init(&ctx->io_buffers_comp,
&ctx->io_buffers_cache);
spin_unlock(&ctx->completion_lock);
return 0;
}
spin_unlock(&ctx->completion_lock);
}
/*
* No free buffers and no completion entries either. Allocate a new
* page worth of buffer entries and add those to our freelist.
*/
page = alloc_page(GFP_KERNEL_ACCOUNT);
if (!page)
return -ENOMEM;
list_add(&page->lru, &ctx->io_buffers_pages);
buf = page_address(page);
bufs_in_page = PAGE_SIZE / sizeof(*buf);
while (bufs_in_page) {
list_add_tail(&buf->list, &ctx->io_buffers_cache);
buf++;
bufs_in_page--;
}
return 0;
}
static int io_add_buffers(struct io_ring_ctx *ctx, struct io_provide_buf *pbuf,
struct io_buffer_list *bl)
{
struct io_buffer *buf;
u64 addr = pbuf->addr;
int i, bid = pbuf->bid;
for (i = 0; i < pbuf->nbufs; i++) {
if (list_empty(&ctx->io_buffers_cache) &&
io_refill_buffer_cache(ctx))
break;
buf = list_first_entry(&ctx->io_buffers_cache, struct io_buffer,
list);
list_move_tail(&buf->list, &bl->buf_list);
buf->addr = addr;
buf->len = min_t(__u32, pbuf->len, MAX_RW_COUNT);
buf->bid = bid;
buf->bgid = pbuf->bgid;
addr += pbuf->len;
bid++;
cond_resched();
}
return i ? 0 : -ENOMEM;
}
int io_provide_buffers(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_provide_buf *p = io_kiocb_to_cmd(req, struct io_provide_buf);
struct io_ring_ctx *ctx = req->ctx;
struct io_buffer_list *bl;
int ret = 0;
io_ring_submit_lock(ctx, issue_flags);
if (unlikely(p->bgid < BGID_ARRAY && !ctx->io_bl)) {
ret = io_init_bl_list(ctx);
if (ret)
goto err;
}
bl = io_buffer_get_list(ctx, p->bgid);
if (unlikely(!bl)) {
bl = kzalloc(sizeof(*bl), GFP_KERNEL_ACCOUNT);
if (!bl) {
ret = -ENOMEM;
goto err;
}
INIT_LIST_HEAD(&bl->buf_list);
ret = io_buffer_add_list(ctx, bl, p->bgid);
if (ret) {
kfree(bl);
goto err;
}
}
/* can't add buffers via this command for a mapped buffer ring */
if (bl->is_mapped) {
ret = -EINVAL;
goto err;
}
ret = io_add_buffers(ctx, p, bl);
err:
io_ring_submit_unlock(ctx, issue_flags);
if (ret < 0)
req_set_fail(req);
io_req_set_res(req, ret, 0);
return IOU_OK;
}
static int io_pin_pbuf_ring(struct io_uring_buf_reg *reg,
struct io_buffer_list *bl)
{
struct io_uring_buf_ring *br;
struct page **pages;
int nr_pages;
pages = io_pin_pages(reg->ring_addr,
flex_array_size(br, bufs, reg->ring_entries),
&nr_pages);
if (IS_ERR(pages))
return PTR_ERR(pages);
br = page_address(pages[0]);
#ifdef SHM_COLOUR
/*
* On platforms that have specific aliasing requirements, SHM_COLOUR
* is set and we must guarantee that the kernel and user side align
* nicely. We cannot do that if IOU_PBUF_RING_MMAP isn't set and
* the application mmap's the provided ring buffer. Fail the request
* if we, by chance, don't end up with aligned addresses. The app
* should use IOU_PBUF_RING_MMAP instead, and liburing will handle
* this transparently.
*/
if ((reg->ring_addr | (unsigned long) br) & (SHM_COLOUR - 1)) {
int i;
for (i = 0; i < nr_pages; i++)
unpin_user_page(pages[i]);
return -EINVAL;
}
#endif
bl->buf_pages = pages;
bl->buf_nr_pages = nr_pages;
bl->buf_ring = br;
bl->is_mapped = 1;
bl->is_mmap = 0;
return 0;
}
static int io_alloc_pbuf_ring(struct io_uring_buf_reg *reg,
struct io_buffer_list *bl)
{
gfp_t gfp = GFP_KERNEL_ACCOUNT | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP;
size_t ring_size;
void *ptr;
ring_size = reg->ring_entries * sizeof(struct io_uring_buf_ring);
ptr = (void *) __get_free_pages(gfp, get_order(ring_size));
if (!ptr)
return -ENOMEM;
bl->buf_ring = ptr;
bl->is_mapped = 1;
bl->is_mmap = 1;
return 0;
}
int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg)
{
struct io_uring_buf_reg reg;
struct io_buffer_list *bl, *free_bl = NULL;
int ret;
if (copy_from_user(®, arg, sizeof(reg)))
return -EFAULT;
if (reg.resv[0] || reg.resv[1] || reg.resv[2])
return -EINVAL;
if (reg.flags & ~IOU_PBUF_RING_MMAP)
return -EINVAL;
if (!(reg.flags & IOU_PBUF_RING_MMAP)) {
if (!reg.ring_addr)
return -EFAULT;
if (reg.ring_addr & ~PAGE_MASK)
return -EINVAL;
} else {
if (reg.ring_addr)
return -EINVAL;
}
if (!is_power_of_2(reg.ring_entries))
return -EINVAL;
/* cannot disambiguate full vs empty due to head/tail size */
if (reg.ring_entries >= 65536)
return -EINVAL;
if (unlikely(reg.bgid < BGID_ARRAY && !ctx->io_bl)) {
int ret = io_init_bl_list(ctx);
if (ret)
return ret;
}
bl = io_buffer_get_list(ctx, reg.bgid);
if (bl) {
/* if mapped buffer ring OR classic exists, don't allow */
if (bl->is_mapped || !list_empty(&bl->buf_list))
return -EEXIST;
} else {
free_bl = bl = kzalloc(sizeof(*bl), GFP_KERNEL);
if (!bl)
return -ENOMEM;
}
if (!(reg.flags & IOU_PBUF_RING_MMAP))
ret = io_pin_pbuf_ring(®, bl);
else
ret = io_alloc_pbuf_ring(®, bl);
if (!ret) {
bl->nr_entries = reg.ring_entries;
bl->mask = reg.ring_entries - 1;
io_buffer_add_list(ctx, bl, reg.bgid);
return 0;
}
kfree(free_bl);
return ret;
}
int io_unregister_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg)
{
struct io_uring_buf_reg reg;
struct io_buffer_list *bl;
if (copy_from_user(®, arg, sizeof(reg)))
return -EFAULT;
if (reg.resv[0] || reg.resv[1] || reg.resv[2])
return -EINVAL;
if (reg.flags)
return -EINVAL;
bl = io_buffer_get_list(ctx, reg.bgid);
if (!bl)
return -ENOENT;
if (!bl->is_mapped)
return -EINVAL;
__io_remove_buffers(ctx, bl, -1U);
if (bl->bgid >= BGID_ARRAY) {
xa_erase(&ctx->io_bl_xa, bl->bgid);
kfree(bl);
}
return 0;
}
void *io_pbuf_get_address(struct io_ring_ctx *ctx, unsigned long bgid)
{
struct io_buffer_list *bl;
bl = io_buffer_get_list(ctx, bgid);
if (!bl || !bl->is_mmap)
return NULL;
return bl->buf_ring;
}
| linux-master | io_uring/kbuf.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/file.h>
#include <linux/io_uring.h>
#include <linux/security.h>
#include <linux/nospec.h>
#include <uapi/linux/io_uring.h>
#include <uapi/asm-generic/ioctls.h>
#include "io_uring.h"
#include "rsrc.h"
#include "uring_cmd.h"
static void io_uring_cmd_work(struct io_kiocb *req, struct io_tw_state *ts)
{
struct io_uring_cmd *ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd);
unsigned issue_flags = ts->locked ? 0 : IO_URING_F_UNLOCKED;
ioucmd->task_work_cb(ioucmd, issue_flags);
}
void __io_uring_cmd_do_in_task(struct io_uring_cmd *ioucmd,
void (*task_work_cb)(struct io_uring_cmd *, unsigned),
unsigned flags)
{
struct io_kiocb *req = cmd_to_io_kiocb(ioucmd);
ioucmd->task_work_cb = task_work_cb;
req->io_task_work.func = io_uring_cmd_work;
__io_req_task_work_add(req, flags);
}
EXPORT_SYMBOL_GPL(__io_uring_cmd_do_in_task);
void io_uring_cmd_do_in_task_lazy(struct io_uring_cmd *ioucmd,
void (*task_work_cb)(struct io_uring_cmd *, unsigned))
{
__io_uring_cmd_do_in_task(ioucmd, task_work_cb, IOU_F_TWQ_LAZY_WAKE);
}
EXPORT_SYMBOL_GPL(io_uring_cmd_do_in_task_lazy);
static inline void io_req_set_cqe32_extra(struct io_kiocb *req,
u64 extra1, u64 extra2)
{
req->big_cqe.extra1 = extra1;
req->big_cqe.extra2 = extra2;
}
/*
* Called by consumers of io_uring_cmd, if they originally returned
* -EIOCBQUEUED upon receiving the command.
*/
void io_uring_cmd_done(struct io_uring_cmd *ioucmd, ssize_t ret, ssize_t res2,
unsigned issue_flags)
{
struct io_kiocb *req = cmd_to_io_kiocb(ioucmd);
if (ret < 0)
req_set_fail(req);
io_req_set_res(req, ret, 0);
if (req->ctx->flags & IORING_SETUP_CQE32)
io_req_set_cqe32_extra(req, res2, 0);
if (req->ctx->flags & IORING_SETUP_IOPOLL) {
/* order with io_iopoll_req_issued() checking ->iopoll_complete */
smp_store_release(&req->iopoll_completed, 1);
} else {
struct io_tw_state ts = {
.locked = !(issue_flags & IO_URING_F_UNLOCKED),
};
io_req_task_complete(req, &ts);
}
}
EXPORT_SYMBOL_GPL(io_uring_cmd_done);
int io_uring_cmd_prep_async(struct io_kiocb *req)
{
struct io_uring_cmd *ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd);
memcpy(req->async_data, ioucmd->sqe, uring_sqe_size(req->ctx));
ioucmd->sqe = req->async_data;
return 0;
}
int io_uring_cmd_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_uring_cmd *ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd);
if (sqe->__pad1)
return -EINVAL;
ioucmd->flags = READ_ONCE(sqe->uring_cmd_flags);
if (ioucmd->flags & ~IORING_URING_CMD_FIXED)
return -EINVAL;
if (ioucmd->flags & IORING_URING_CMD_FIXED) {
struct io_ring_ctx *ctx = req->ctx;
u16 index;
req->buf_index = READ_ONCE(sqe->buf_index);
if (unlikely(req->buf_index >= ctx->nr_user_bufs))
return -EFAULT;
index = array_index_nospec(req->buf_index, ctx->nr_user_bufs);
req->imu = ctx->user_bufs[index];
io_req_set_rsrc_node(req, ctx, 0);
}
ioucmd->sqe = sqe;
ioucmd->cmd_op = READ_ONCE(sqe->cmd_op);
return 0;
}
int io_uring_cmd(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_uring_cmd *ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd);
struct io_ring_ctx *ctx = req->ctx;
struct file *file = req->file;
int ret;
if (!file->f_op->uring_cmd)
return -EOPNOTSUPP;
ret = security_uring_cmd(ioucmd);
if (ret)
return ret;
if (ctx->flags & IORING_SETUP_SQE128)
issue_flags |= IO_URING_F_SQE128;
if (ctx->flags & IORING_SETUP_CQE32)
issue_flags |= IO_URING_F_CQE32;
if (ctx->flags & IORING_SETUP_IOPOLL) {
if (!file->f_op->uring_cmd_iopoll)
return -EOPNOTSUPP;
issue_flags |= IO_URING_F_IOPOLL;
req->iopoll_completed = 0;
WRITE_ONCE(ioucmd->cookie, NULL);
}
ret = file->f_op->uring_cmd(ioucmd, issue_flags);
if (ret == -EAGAIN) {
if (!req_has_async_data(req)) {
if (io_alloc_async_data(req))
return -ENOMEM;
io_uring_cmd_prep_async(req);
}
return -EAGAIN;
}
if (ret != -EIOCBQUEUED) {
if (ret < 0)
req_set_fail(req);
io_req_set_res(req, ret, 0);
return ret;
}
return IOU_ISSUE_SKIP_COMPLETE;
}
int io_uring_cmd_import_fixed(u64 ubuf, unsigned long len, int rw,
struct iov_iter *iter, void *ioucmd)
{
struct io_kiocb *req = cmd_to_io_kiocb(ioucmd);
return io_import_fixed(rw, iter, req->imu, ubuf, len);
}
EXPORT_SYMBOL_GPL(io_uring_cmd_import_fixed);
int io_uring_cmd_sock(struct io_uring_cmd *cmd, unsigned int issue_flags)
{
struct socket *sock = cmd->file->private_data;
struct sock *sk = sock->sk;
struct proto *prot = READ_ONCE(sk->sk_prot);
int ret, arg = 0;
if (!prot || !prot->ioctl)
return -EOPNOTSUPP;
switch (cmd->sqe->cmd_op) {
case SOCKET_URING_OP_SIOCINQ:
ret = prot->ioctl(sk, SIOCINQ, &arg);
if (ret)
return ret;
return arg;
case SOCKET_URING_OP_SIOCOUTQ:
ret = prot->ioctl(sk, SIOCOUTQ, &arg);
if (ret)
return ret;
return arg;
default:
return -EOPNOTSUPP;
}
}
EXPORT_SYMBOL_GPL(io_uring_cmd_sock);
| linux-master | io_uring/uring_cmd.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/poll.h>
#include <linux/hashtable.h>
#include <linux/io_uring.h>
#include <trace/events/io_uring.h>
#include <uapi/linux/io_uring.h>
#include "io_uring.h"
#include "refs.h"
#include "opdef.h"
#include "kbuf.h"
#include "poll.h"
#include "cancel.h"
struct io_poll_update {
struct file *file;
u64 old_user_data;
u64 new_user_data;
__poll_t events;
bool update_events;
bool update_user_data;
};
struct io_poll_table {
struct poll_table_struct pt;
struct io_kiocb *req;
int nr_entries;
int error;
bool owning;
/* output value, set only if arm poll returns >0 */
__poll_t result_mask;
};
#define IO_POLL_CANCEL_FLAG BIT(31)
#define IO_POLL_RETRY_FLAG BIT(30)
#define IO_POLL_REF_MASK GENMASK(29, 0)
/*
* We usually have 1-2 refs taken, 128 is more than enough and we want to
* maximise the margin between this amount and the moment when it overflows.
*/
#define IO_POLL_REF_BIAS 128
#define IO_WQE_F_DOUBLE 1
static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
void *key);
static inline struct io_kiocb *wqe_to_req(struct wait_queue_entry *wqe)
{
unsigned long priv = (unsigned long)wqe->private;
return (struct io_kiocb *)(priv & ~IO_WQE_F_DOUBLE);
}
static inline bool wqe_is_double(struct wait_queue_entry *wqe)
{
unsigned long priv = (unsigned long)wqe->private;
return priv & IO_WQE_F_DOUBLE;
}
static bool io_poll_get_ownership_slowpath(struct io_kiocb *req)
{
int v;
/*
* poll_refs are already elevated and we don't have much hope for
* grabbing the ownership. Instead of incrementing set a retry flag
* to notify the loop that there might have been some change.
*/
v = atomic_fetch_or(IO_POLL_RETRY_FLAG, &req->poll_refs);
if (v & IO_POLL_REF_MASK)
return false;
return !(atomic_fetch_inc(&req->poll_refs) & IO_POLL_REF_MASK);
}
/*
* If refs part of ->poll_refs (see IO_POLL_REF_MASK) is 0, it's free. We can
* bump it and acquire ownership. It's disallowed to modify requests while not
* owning it, that prevents from races for enqueueing task_work's and b/w
* arming poll and wakeups.
*/
static inline bool io_poll_get_ownership(struct io_kiocb *req)
{
if (unlikely(atomic_read(&req->poll_refs) >= IO_POLL_REF_BIAS))
return io_poll_get_ownership_slowpath(req);
return !(atomic_fetch_inc(&req->poll_refs) & IO_POLL_REF_MASK);
}
static void io_poll_mark_cancelled(struct io_kiocb *req)
{
atomic_or(IO_POLL_CANCEL_FLAG, &req->poll_refs);
}
static struct io_poll *io_poll_get_double(struct io_kiocb *req)
{
/* pure poll stashes this in ->async_data, poll driven retry elsewhere */
if (req->opcode == IORING_OP_POLL_ADD)
return req->async_data;
return req->apoll->double_poll;
}
static struct io_poll *io_poll_get_single(struct io_kiocb *req)
{
if (req->opcode == IORING_OP_POLL_ADD)
return io_kiocb_to_cmd(req, struct io_poll);
return &req->apoll->poll;
}
static void io_poll_req_insert(struct io_kiocb *req)
{
struct io_hash_table *table = &req->ctx->cancel_table;
u32 index = hash_long(req->cqe.user_data, table->hash_bits);
struct io_hash_bucket *hb = &table->hbs[index];
spin_lock(&hb->lock);
hlist_add_head(&req->hash_node, &hb->list);
spin_unlock(&hb->lock);
}
static void io_poll_req_delete(struct io_kiocb *req, struct io_ring_ctx *ctx)
{
struct io_hash_table *table = &req->ctx->cancel_table;
u32 index = hash_long(req->cqe.user_data, table->hash_bits);
spinlock_t *lock = &table->hbs[index].lock;
spin_lock(lock);
hash_del(&req->hash_node);
spin_unlock(lock);
}
static void io_poll_req_insert_locked(struct io_kiocb *req)
{
struct io_hash_table *table = &req->ctx->cancel_table_locked;
u32 index = hash_long(req->cqe.user_data, table->hash_bits);
lockdep_assert_held(&req->ctx->uring_lock);
hlist_add_head(&req->hash_node, &table->hbs[index].list);
}
static void io_poll_tw_hash_eject(struct io_kiocb *req, struct io_tw_state *ts)
{
struct io_ring_ctx *ctx = req->ctx;
if (req->flags & REQ_F_HASH_LOCKED) {
/*
* ->cancel_table_locked is protected by ->uring_lock in
* contrast to per bucket spinlocks. Likely, tctx_task_work()
* already grabbed the mutex for us, but there is a chance it
* failed.
*/
io_tw_lock(ctx, ts);
hash_del(&req->hash_node);
req->flags &= ~REQ_F_HASH_LOCKED;
} else {
io_poll_req_delete(req, ctx);
}
}
static void io_init_poll_iocb(struct io_poll *poll, __poll_t events)
{
poll->head = NULL;
#define IO_POLL_UNMASK (EPOLLERR|EPOLLHUP|EPOLLNVAL|EPOLLRDHUP)
/* mask in events that we always want/need */
poll->events = events | IO_POLL_UNMASK;
INIT_LIST_HEAD(&poll->wait.entry);
init_waitqueue_func_entry(&poll->wait, io_poll_wake);
}
static inline void io_poll_remove_entry(struct io_poll *poll)
{
struct wait_queue_head *head = smp_load_acquire(&poll->head);
if (head) {
spin_lock_irq(&head->lock);
list_del_init(&poll->wait.entry);
poll->head = NULL;
spin_unlock_irq(&head->lock);
}
}
static void io_poll_remove_entries(struct io_kiocb *req)
{
/*
* Nothing to do if neither of those flags are set. Avoid dipping
* into the poll/apoll/double cachelines if we can.
*/
if (!(req->flags & (REQ_F_SINGLE_POLL | REQ_F_DOUBLE_POLL)))
return;
/*
* While we hold the waitqueue lock and the waitqueue is nonempty,
* wake_up_pollfree() will wait for us. However, taking the waitqueue
* lock in the first place can race with the waitqueue being freed.
*
* We solve this as eventpoll does: by taking advantage of the fact that
* all users of wake_up_pollfree() will RCU-delay the actual free. If
* we enter rcu_read_lock() and see that the pointer to the queue is
* non-NULL, we can then lock it without the memory being freed out from
* under us.
*
* Keep holding rcu_read_lock() as long as we hold the queue lock, in
* case the caller deletes the entry from the queue, leaving it empty.
* In that case, only RCU prevents the queue memory from being freed.
*/
rcu_read_lock();
if (req->flags & REQ_F_SINGLE_POLL)
io_poll_remove_entry(io_poll_get_single(req));
if (req->flags & REQ_F_DOUBLE_POLL)
io_poll_remove_entry(io_poll_get_double(req));
rcu_read_unlock();
}
enum {
IOU_POLL_DONE = 0,
IOU_POLL_NO_ACTION = 1,
IOU_POLL_REMOVE_POLL_USE_RES = 2,
IOU_POLL_REISSUE = 3,
};
/*
* All poll tw should go through this. Checks for poll events, manages
* references, does rewait, etc.
*
* Returns a negative error on failure. IOU_POLL_NO_ACTION when no action
* require, which is either spurious wakeup or multishot CQE is served.
* IOU_POLL_DONE when it's done with the request, then the mask is stored in
* req->cqe.res. IOU_POLL_REMOVE_POLL_USE_RES indicates to remove multishot
* poll and that the result is stored in req->cqe.
*/
static int io_poll_check_events(struct io_kiocb *req, struct io_tw_state *ts)
{
int v;
/* req->task == current here, checking PF_EXITING is safe */
if (unlikely(req->task->flags & PF_EXITING))
return -ECANCELED;
do {
v = atomic_read(&req->poll_refs);
if (unlikely(v != 1)) {
/* tw should be the owner and so have some refs */
if (WARN_ON_ONCE(!(v & IO_POLL_REF_MASK)))
return IOU_POLL_NO_ACTION;
if (v & IO_POLL_CANCEL_FLAG)
return -ECANCELED;
/*
* cqe.res contains only events of the first wake up
* and all others are to be lost. Redo vfs_poll() to get
* up to date state.
*/
if ((v & IO_POLL_REF_MASK) != 1)
req->cqe.res = 0;
if (v & IO_POLL_RETRY_FLAG) {
req->cqe.res = 0;
/*
* We won't find new events that came in between
* vfs_poll and the ref put unless we clear the
* flag in advance.
*/
atomic_andnot(IO_POLL_RETRY_FLAG, &req->poll_refs);
v &= ~IO_POLL_RETRY_FLAG;
}
}
/* the mask was stashed in __io_poll_execute */
if (!req->cqe.res) {
struct poll_table_struct pt = { ._key = req->apoll_events };
req->cqe.res = vfs_poll(req->file, &pt) & req->apoll_events;
/*
* We got woken with a mask, but someone else got to
* it first. The above vfs_poll() doesn't add us back
* to the waitqueue, so if we get nothing back, we
* should be safe and attempt a reissue.
*/
if (unlikely(!req->cqe.res)) {
/* Multishot armed need not reissue */
if (!(req->apoll_events & EPOLLONESHOT))
continue;
return IOU_POLL_REISSUE;
}
}
if (req->apoll_events & EPOLLONESHOT)
return IOU_POLL_DONE;
/* multishot, just fill a CQE and proceed */
if (!(req->flags & REQ_F_APOLL_MULTISHOT)) {
__poll_t mask = mangle_poll(req->cqe.res &
req->apoll_events);
if (!io_fill_cqe_req_aux(req, ts->locked, mask,
IORING_CQE_F_MORE)) {
io_req_set_res(req, mask, 0);
return IOU_POLL_REMOVE_POLL_USE_RES;
}
} else {
int ret = io_poll_issue(req, ts);
if (ret == IOU_STOP_MULTISHOT)
return IOU_POLL_REMOVE_POLL_USE_RES;
if (ret < 0)
return ret;
}
/* force the next iteration to vfs_poll() */
req->cqe.res = 0;
/*
* Release all references, retry if someone tried to restart
* task_work while we were executing it.
*/
} while (atomic_sub_return(v & IO_POLL_REF_MASK, &req->poll_refs) &
IO_POLL_REF_MASK);
return IOU_POLL_NO_ACTION;
}
void io_poll_task_func(struct io_kiocb *req, struct io_tw_state *ts)
{
int ret;
ret = io_poll_check_events(req, ts);
if (ret == IOU_POLL_NO_ACTION)
return;
io_poll_remove_entries(req);
io_poll_tw_hash_eject(req, ts);
if (req->opcode == IORING_OP_POLL_ADD) {
if (ret == IOU_POLL_DONE) {
struct io_poll *poll;
poll = io_kiocb_to_cmd(req, struct io_poll);
req->cqe.res = mangle_poll(req->cqe.res & poll->events);
} else if (ret == IOU_POLL_REISSUE) {
io_req_task_submit(req, ts);
return;
} else if (ret != IOU_POLL_REMOVE_POLL_USE_RES) {
req->cqe.res = ret;
req_set_fail(req);
}
io_req_set_res(req, req->cqe.res, 0);
io_req_task_complete(req, ts);
} else {
io_tw_lock(req->ctx, ts);
if (ret == IOU_POLL_REMOVE_POLL_USE_RES)
io_req_task_complete(req, ts);
else if (ret == IOU_POLL_DONE || ret == IOU_POLL_REISSUE)
io_req_task_submit(req, ts);
else
io_req_defer_failed(req, ret);
}
}
static void __io_poll_execute(struct io_kiocb *req, int mask)
{
io_req_set_res(req, mask, 0);
req->io_task_work.func = io_poll_task_func;
trace_io_uring_task_add(req, mask);
io_req_task_work_add(req);
}
static inline void io_poll_execute(struct io_kiocb *req, int res)
{
if (io_poll_get_ownership(req))
__io_poll_execute(req, res);
}
static void io_poll_cancel_req(struct io_kiocb *req)
{
io_poll_mark_cancelled(req);
/* kick tw, which should complete the request */
io_poll_execute(req, 0);
}
#define IO_ASYNC_POLL_COMMON (EPOLLONESHOT | EPOLLPRI)
static __cold int io_pollfree_wake(struct io_kiocb *req, struct io_poll *poll)
{
io_poll_mark_cancelled(req);
/* we have to kick tw in case it's not already */
io_poll_execute(req, 0);
/*
* If the waitqueue is being freed early but someone is already
* holds ownership over it, we have to tear down the request as
* best we can. That means immediately removing the request from
* its waitqueue and preventing all further accesses to the
* waitqueue via the request.
*/
list_del_init(&poll->wait.entry);
/*
* Careful: this *must* be the last step, since as soon
* as req->head is NULL'ed out, the request can be
* completed and freed, since aio_poll_complete_work()
* will no longer need to take the waitqueue lock.
*/
smp_store_release(&poll->head, NULL);
return 1;
}
static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
void *key)
{
struct io_kiocb *req = wqe_to_req(wait);
struct io_poll *poll = container_of(wait, struct io_poll, wait);
__poll_t mask = key_to_poll(key);
if (unlikely(mask & POLLFREE))
return io_pollfree_wake(req, poll);
/* for instances that support it check for an event match first */
if (mask && !(mask & (poll->events & ~IO_ASYNC_POLL_COMMON)))
return 0;
if (io_poll_get_ownership(req)) {
/*
* If we trigger a multishot poll off our own wakeup path,
* disable multishot as there is a circular dependency between
* CQ posting and triggering the event.
*/
if (mask & EPOLL_URING_WAKE)
poll->events |= EPOLLONESHOT;
/* optional, saves extra locking for removal in tw handler */
if (mask && poll->events & EPOLLONESHOT) {
list_del_init(&poll->wait.entry);
poll->head = NULL;
if (wqe_is_double(wait))
req->flags &= ~REQ_F_DOUBLE_POLL;
else
req->flags &= ~REQ_F_SINGLE_POLL;
}
__io_poll_execute(req, mask);
}
return 1;
}
/* fails only when polling is already completing by the first entry */
static bool io_poll_double_prepare(struct io_kiocb *req)
{
struct wait_queue_head *head;
struct io_poll *poll = io_poll_get_single(req);
/* head is RCU protected, see io_poll_remove_entries() comments */
rcu_read_lock();
head = smp_load_acquire(&poll->head);
/*
* poll arm might not hold ownership and so race for req->flags with
* io_poll_wake(). There is only one poll entry queued, serialise with
* it by taking its head lock. As we're still arming the tw hanlder
* is not going to be run, so there are no races with it.
*/
if (head) {
spin_lock_irq(&head->lock);
req->flags |= REQ_F_DOUBLE_POLL;
if (req->opcode == IORING_OP_POLL_ADD)
req->flags |= REQ_F_ASYNC_DATA;
spin_unlock_irq(&head->lock);
}
rcu_read_unlock();
return !!head;
}
static void __io_queue_proc(struct io_poll *poll, struct io_poll_table *pt,
struct wait_queue_head *head,
struct io_poll **poll_ptr)
{
struct io_kiocb *req = pt->req;
unsigned long wqe_private = (unsigned long) req;
/*
* The file being polled uses multiple waitqueues for poll handling
* (e.g. one for read, one for write). Setup a separate io_poll
* if this happens.
*/
if (unlikely(pt->nr_entries)) {
struct io_poll *first = poll;
/* double add on the same waitqueue head, ignore */
if (first->head == head)
return;
/* already have a 2nd entry, fail a third attempt */
if (*poll_ptr) {
if ((*poll_ptr)->head == head)
return;
pt->error = -EINVAL;
return;
}
poll = kmalloc(sizeof(*poll), GFP_ATOMIC);
if (!poll) {
pt->error = -ENOMEM;
return;
}
/* mark as double wq entry */
wqe_private |= IO_WQE_F_DOUBLE;
io_init_poll_iocb(poll, first->events);
if (!io_poll_double_prepare(req)) {
/* the request is completing, just back off */
kfree(poll);
return;
}
*poll_ptr = poll;
} else {
/* fine to modify, there is no poll queued to race with us */
req->flags |= REQ_F_SINGLE_POLL;
}
pt->nr_entries++;
poll->head = head;
poll->wait.private = (void *) wqe_private;
if (poll->events & EPOLLEXCLUSIVE)
add_wait_queue_exclusive(head, &poll->wait);
else
add_wait_queue(head, &poll->wait);
}
static void io_poll_queue_proc(struct file *file, struct wait_queue_head *head,
struct poll_table_struct *p)
{
struct io_poll_table *pt = container_of(p, struct io_poll_table, pt);
struct io_poll *poll = io_kiocb_to_cmd(pt->req, struct io_poll);
__io_queue_proc(poll, pt, head,
(struct io_poll **) &pt->req->async_data);
}
static bool io_poll_can_finish_inline(struct io_kiocb *req,
struct io_poll_table *pt)
{
return pt->owning || io_poll_get_ownership(req);
}
static void io_poll_add_hash(struct io_kiocb *req)
{
if (req->flags & REQ_F_HASH_LOCKED)
io_poll_req_insert_locked(req);
else
io_poll_req_insert(req);
}
/*
* Returns 0 when it's handed over for polling. The caller owns the requests if
* it returns non-zero, but otherwise should not touch it. Negative values
* contain an error code. When the result is >0, the polling has completed
* inline and ipt.result_mask is set to the mask.
*/
static int __io_arm_poll_handler(struct io_kiocb *req,
struct io_poll *poll,
struct io_poll_table *ipt, __poll_t mask,
unsigned issue_flags)
{
struct io_ring_ctx *ctx = req->ctx;
INIT_HLIST_NODE(&req->hash_node);
req->work.cancel_seq = atomic_read(&ctx->cancel_seq);
io_init_poll_iocb(poll, mask);
poll->file = req->file;
req->apoll_events = poll->events;
ipt->pt._key = mask;
ipt->req = req;
ipt->error = 0;
ipt->nr_entries = 0;
/*
* Polling is either completed here or via task_work, so if we're in the
* task context we're naturally serialised with tw by merit of running
* the same task. When it's io-wq, take the ownership to prevent tw
* from running. However, when we're in the task context, skip taking
* it as an optimisation.
*
* Note: even though the request won't be completed/freed, without
* ownership we still can race with io_poll_wake().
* io_poll_can_finish_inline() tries to deal with that.
*/
ipt->owning = issue_flags & IO_URING_F_UNLOCKED;
atomic_set(&req->poll_refs, (int)ipt->owning);
/* io-wq doesn't hold uring_lock */
if (issue_flags & IO_URING_F_UNLOCKED)
req->flags &= ~REQ_F_HASH_LOCKED;
mask = vfs_poll(req->file, &ipt->pt) & poll->events;
if (unlikely(ipt->error || !ipt->nr_entries)) {
io_poll_remove_entries(req);
if (!io_poll_can_finish_inline(req, ipt)) {
io_poll_mark_cancelled(req);
return 0;
} else if (mask && (poll->events & EPOLLET)) {
ipt->result_mask = mask;
return 1;
}
return ipt->error ?: -EINVAL;
}
if (mask &&
((poll->events & (EPOLLET|EPOLLONESHOT)) == (EPOLLET|EPOLLONESHOT))) {
if (!io_poll_can_finish_inline(req, ipt)) {
io_poll_add_hash(req);
return 0;
}
io_poll_remove_entries(req);
ipt->result_mask = mask;
/* no one else has access to the req, forget about the ref */
return 1;
}
io_poll_add_hash(req);
if (mask && (poll->events & EPOLLET) &&
io_poll_can_finish_inline(req, ipt)) {
__io_poll_execute(req, mask);
return 0;
}
if (ipt->owning) {
/*
* Try to release ownership. If we see a change of state, e.g.
* poll was waken up, queue up a tw, it'll deal with it.
*/
if (atomic_cmpxchg(&req->poll_refs, 1, 0) != 1)
__io_poll_execute(req, 0);
}
return 0;
}
static void io_async_queue_proc(struct file *file, struct wait_queue_head *head,
struct poll_table_struct *p)
{
struct io_poll_table *pt = container_of(p, struct io_poll_table, pt);
struct async_poll *apoll = pt->req->apoll;
__io_queue_proc(&apoll->poll, pt, head, &apoll->double_poll);
}
/*
* We can't reliably detect loops in repeated poll triggers and issue
* subsequently failing. But rather than fail these immediately, allow a
* certain amount of retries before we give up. Given that this condition
* should _rarely_ trigger even once, we should be fine with a larger value.
*/
#define APOLL_MAX_RETRY 128
static struct async_poll *io_req_alloc_apoll(struct io_kiocb *req,
unsigned issue_flags)
{
struct io_ring_ctx *ctx = req->ctx;
struct io_cache_entry *entry;
struct async_poll *apoll;
if (req->flags & REQ_F_POLLED) {
apoll = req->apoll;
kfree(apoll->double_poll);
} else if (!(issue_flags & IO_URING_F_UNLOCKED)) {
entry = io_alloc_cache_get(&ctx->apoll_cache);
if (entry == NULL)
goto alloc_apoll;
apoll = container_of(entry, struct async_poll, cache);
apoll->poll.retries = APOLL_MAX_RETRY;
} else {
alloc_apoll:
apoll = kmalloc(sizeof(*apoll), GFP_ATOMIC);
if (unlikely(!apoll))
return NULL;
apoll->poll.retries = APOLL_MAX_RETRY;
}
apoll->double_poll = NULL;
req->apoll = apoll;
if (unlikely(!--apoll->poll.retries))
return NULL;
return apoll;
}
int io_arm_poll_handler(struct io_kiocb *req, unsigned issue_flags)
{
const struct io_issue_def *def = &io_issue_defs[req->opcode];
struct async_poll *apoll;
struct io_poll_table ipt;
__poll_t mask = POLLPRI | POLLERR | EPOLLET;
int ret;
/*
* apoll requests already grab the mutex to complete in the tw handler,
* so removal from the mutex-backed hash is free, use it by default.
*/
req->flags |= REQ_F_HASH_LOCKED;
if (!def->pollin && !def->pollout)
return IO_APOLL_ABORTED;
if (!file_can_poll(req->file))
return IO_APOLL_ABORTED;
if (!(req->flags & REQ_F_APOLL_MULTISHOT))
mask |= EPOLLONESHOT;
if (def->pollin) {
mask |= EPOLLIN | EPOLLRDNORM;
/* If reading from MSG_ERRQUEUE using recvmsg, ignore POLLIN */
if (req->flags & REQ_F_CLEAR_POLLIN)
mask &= ~EPOLLIN;
} else {
mask |= EPOLLOUT | EPOLLWRNORM;
}
if (def->poll_exclusive)
mask |= EPOLLEXCLUSIVE;
apoll = io_req_alloc_apoll(req, issue_flags);
if (!apoll)
return IO_APOLL_ABORTED;
req->flags &= ~(REQ_F_SINGLE_POLL | REQ_F_DOUBLE_POLL);
req->flags |= REQ_F_POLLED;
ipt.pt._qproc = io_async_queue_proc;
io_kbuf_recycle(req, issue_flags);
ret = __io_arm_poll_handler(req, &apoll->poll, &ipt, mask, issue_flags);
if (ret)
return ret > 0 ? IO_APOLL_READY : IO_APOLL_ABORTED;
trace_io_uring_poll_arm(req, mask, apoll->poll.events);
return IO_APOLL_OK;
}
static __cold bool io_poll_remove_all_table(struct task_struct *tsk,
struct io_hash_table *table,
bool cancel_all)
{
unsigned nr_buckets = 1U << table->hash_bits;
struct hlist_node *tmp;
struct io_kiocb *req;
bool found = false;
int i;
for (i = 0; i < nr_buckets; i++) {
struct io_hash_bucket *hb = &table->hbs[i];
spin_lock(&hb->lock);
hlist_for_each_entry_safe(req, tmp, &hb->list, hash_node) {
if (io_match_task_safe(req, tsk, cancel_all)) {
hlist_del_init(&req->hash_node);
io_poll_cancel_req(req);
found = true;
}
}
spin_unlock(&hb->lock);
}
return found;
}
/*
* Returns true if we found and killed one or more poll requests
*/
__cold bool io_poll_remove_all(struct io_ring_ctx *ctx, struct task_struct *tsk,
bool cancel_all)
__must_hold(&ctx->uring_lock)
{
bool ret;
ret = io_poll_remove_all_table(tsk, &ctx->cancel_table, cancel_all);
ret |= io_poll_remove_all_table(tsk, &ctx->cancel_table_locked, cancel_all);
return ret;
}
static struct io_kiocb *io_poll_find(struct io_ring_ctx *ctx, bool poll_only,
struct io_cancel_data *cd,
struct io_hash_table *table,
struct io_hash_bucket **out_bucket)
{
struct io_kiocb *req;
u32 index = hash_long(cd->data, table->hash_bits);
struct io_hash_bucket *hb = &table->hbs[index];
*out_bucket = NULL;
spin_lock(&hb->lock);
hlist_for_each_entry(req, &hb->list, hash_node) {
if (cd->data != req->cqe.user_data)
continue;
if (poll_only && req->opcode != IORING_OP_POLL_ADD)
continue;
if (cd->flags & IORING_ASYNC_CANCEL_ALL) {
if (cd->seq == req->work.cancel_seq)
continue;
req->work.cancel_seq = cd->seq;
}
*out_bucket = hb;
return req;
}
spin_unlock(&hb->lock);
return NULL;
}
static struct io_kiocb *io_poll_file_find(struct io_ring_ctx *ctx,
struct io_cancel_data *cd,
struct io_hash_table *table,
struct io_hash_bucket **out_bucket)
{
unsigned nr_buckets = 1U << table->hash_bits;
struct io_kiocb *req;
int i;
*out_bucket = NULL;
for (i = 0; i < nr_buckets; i++) {
struct io_hash_bucket *hb = &table->hbs[i];
spin_lock(&hb->lock);
hlist_for_each_entry(req, &hb->list, hash_node) {
if (io_cancel_req_match(req, cd)) {
*out_bucket = hb;
return req;
}
}
spin_unlock(&hb->lock);
}
return NULL;
}
static int io_poll_disarm(struct io_kiocb *req)
{
if (!req)
return -ENOENT;
if (!io_poll_get_ownership(req))
return -EALREADY;
io_poll_remove_entries(req);
hash_del(&req->hash_node);
return 0;
}
static int __io_poll_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd,
struct io_hash_table *table)
{
struct io_hash_bucket *bucket;
struct io_kiocb *req;
if (cd->flags & (IORING_ASYNC_CANCEL_FD | IORING_ASYNC_CANCEL_OP |
IORING_ASYNC_CANCEL_ANY))
req = io_poll_file_find(ctx, cd, table, &bucket);
else
req = io_poll_find(ctx, false, cd, table, &bucket);
if (req)
io_poll_cancel_req(req);
if (bucket)
spin_unlock(&bucket->lock);
return req ? 0 : -ENOENT;
}
int io_poll_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd,
unsigned issue_flags)
{
int ret;
ret = __io_poll_cancel(ctx, cd, &ctx->cancel_table);
if (ret != -ENOENT)
return ret;
io_ring_submit_lock(ctx, issue_flags);
ret = __io_poll_cancel(ctx, cd, &ctx->cancel_table_locked);
io_ring_submit_unlock(ctx, issue_flags);
return ret;
}
static __poll_t io_poll_parse_events(const struct io_uring_sqe *sqe,
unsigned int flags)
{
u32 events;
events = READ_ONCE(sqe->poll32_events);
#ifdef __BIG_ENDIAN
events = swahw32(events);
#endif
if (!(flags & IORING_POLL_ADD_MULTI))
events |= EPOLLONESHOT;
if (!(flags & IORING_POLL_ADD_LEVEL))
events |= EPOLLET;
return demangle_poll(events) |
(events & (EPOLLEXCLUSIVE|EPOLLONESHOT|EPOLLET));
}
int io_poll_remove_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_poll_update *upd = io_kiocb_to_cmd(req, struct io_poll_update);
u32 flags;
if (sqe->buf_index || sqe->splice_fd_in)
return -EINVAL;
flags = READ_ONCE(sqe->len);
if (flags & ~(IORING_POLL_UPDATE_EVENTS | IORING_POLL_UPDATE_USER_DATA |
IORING_POLL_ADD_MULTI))
return -EINVAL;
/* meaningless without update */
if (flags == IORING_POLL_ADD_MULTI)
return -EINVAL;
upd->old_user_data = READ_ONCE(sqe->addr);
upd->update_events = flags & IORING_POLL_UPDATE_EVENTS;
upd->update_user_data = flags & IORING_POLL_UPDATE_USER_DATA;
upd->new_user_data = READ_ONCE(sqe->off);
if (!upd->update_user_data && upd->new_user_data)
return -EINVAL;
if (upd->update_events)
upd->events = io_poll_parse_events(sqe, flags);
else if (sqe->poll32_events)
return -EINVAL;
return 0;
}
int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_poll *poll = io_kiocb_to_cmd(req, struct io_poll);
u32 flags;
if (sqe->buf_index || sqe->off || sqe->addr)
return -EINVAL;
flags = READ_ONCE(sqe->len);
if (flags & ~IORING_POLL_ADD_MULTI)
return -EINVAL;
if ((flags & IORING_POLL_ADD_MULTI) && (req->flags & REQ_F_CQE_SKIP))
return -EINVAL;
poll->events = io_poll_parse_events(sqe, flags);
return 0;
}
int io_poll_add(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_poll *poll = io_kiocb_to_cmd(req, struct io_poll);
struct io_poll_table ipt;
int ret;
ipt.pt._qproc = io_poll_queue_proc;
/*
* If sqpoll or single issuer, there is no contention for ->uring_lock
* and we'll end up holding it in tw handlers anyway.
*/
if (req->ctx->flags & (IORING_SETUP_SQPOLL|IORING_SETUP_SINGLE_ISSUER))
req->flags |= REQ_F_HASH_LOCKED;
ret = __io_arm_poll_handler(req, poll, &ipt, poll->events, issue_flags);
if (ret > 0) {
io_req_set_res(req, ipt.result_mask, 0);
return IOU_OK;
}
return ret ?: IOU_ISSUE_SKIP_COMPLETE;
}
int io_poll_remove(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_poll_update *poll_update = io_kiocb_to_cmd(req, struct io_poll_update);
struct io_ring_ctx *ctx = req->ctx;
struct io_cancel_data cd = { .ctx = ctx, .data = poll_update->old_user_data, };
struct io_hash_bucket *bucket;
struct io_kiocb *preq;
int ret2, ret = 0;
struct io_tw_state ts = { .locked = true };
io_ring_submit_lock(ctx, issue_flags);
preq = io_poll_find(ctx, true, &cd, &ctx->cancel_table, &bucket);
ret2 = io_poll_disarm(preq);
if (bucket)
spin_unlock(&bucket->lock);
if (!ret2)
goto found;
if (ret2 != -ENOENT) {
ret = ret2;
goto out;
}
preq = io_poll_find(ctx, true, &cd, &ctx->cancel_table_locked, &bucket);
ret2 = io_poll_disarm(preq);
if (bucket)
spin_unlock(&bucket->lock);
if (ret2) {
ret = ret2;
goto out;
}
found:
if (WARN_ON_ONCE(preq->opcode != IORING_OP_POLL_ADD)) {
ret = -EFAULT;
goto out;
}
if (poll_update->update_events || poll_update->update_user_data) {
/* only mask one event flags, keep behavior flags */
if (poll_update->update_events) {
struct io_poll *poll = io_kiocb_to_cmd(preq, struct io_poll);
poll->events &= ~0xffff;
poll->events |= poll_update->events & 0xffff;
poll->events |= IO_POLL_UNMASK;
}
if (poll_update->update_user_data)
preq->cqe.user_data = poll_update->new_user_data;
ret2 = io_poll_add(preq, issue_flags & ~IO_URING_F_UNLOCKED);
/* successfully updated, don't complete poll request */
if (!ret2 || ret2 == -EIOCBQUEUED)
goto out;
}
req_set_fail(preq);
io_req_set_res(preq, -ECANCELED, 0);
io_req_task_complete(preq, &ts);
out:
io_ring_submit_unlock(ctx, issue_flags);
if (ret < 0) {
req_set_fail(req);
return ret;
}
/* complete update request, we're done with it */
io_req_set_res(req, ret, 0);
return IOU_OK;
}
void io_apoll_cache_free(struct io_cache_entry *entry)
{
kfree(container_of(entry, struct async_poll, cache));
}
| linux-master | io_uring/poll.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/nospec.h>
#include <linux/hugetlb.h>
#include <linux/compat.h>
#include <linux/io_uring.h>
#include <uapi/linux/io_uring.h>
#include "io_uring.h"
#include "openclose.h"
#include "rsrc.h"
struct io_rsrc_update {
struct file *file;
u64 arg;
u32 nr_args;
u32 offset;
};
static void io_rsrc_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc);
static void io_rsrc_file_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc);
static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
struct io_mapped_ubuf **pimu,
struct page **last_hpage);
/* only define max */
#define IORING_MAX_FIXED_FILES (1U << 20)
#define IORING_MAX_REG_BUFFERS (1U << 14)
static const struct io_mapped_ubuf dummy_ubuf = {
/* set invalid range, so io_import_fixed() fails meeting it */
.ubuf = -1UL,
.ubuf_end = 0,
};
int __io_account_mem(struct user_struct *user, unsigned long nr_pages)
{
unsigned long page_limit, cur_pages, new_pages;
if (!nr_pages)
return 0;
/* Don't allow more pages than we can safely lock */
page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
cur_pages = atomic_long_read(&user->locked_vm);
do {
new_pages = cur_pages + nr_pages;
if (new_pages > page_limit)
return -ENOMEM;
} while (!atomic_long_try_cmpxchg(&user->locked_vm,
&cur_pages, new_pages));
return 0;
}
static void io_unaccount_mem(struct io_ring_ctx *ctx, unsigned long nr_pages)
{
if (ctx->user)
__io_unaccount_mem(ctx->user, nr_pages);
if (ctx->mm_account)
atomic64_sub(nr_pages, &ctx->mm_account->pinned_vm);
}
static int io_account_mem(struct io_ring_ctx *ctx, unsigned long nr_pages)
{
int ret;
if (ctx->user) {
ret = __io_account_mem(ctx->user, nr_pages);
if (ret)
return ret;
}
if (ctx->mm_account)
atomic64_add(nr_pages, &ctx->mm_account->pinned_vm);
return 0;
}
static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst,
void __user *arg, unsigned index)
{
struct iovec __user *src;
#ifdef CONFIG_COMPAT
if (ctx->compat) {
struct compat_iovec __user *ciovs;
struct compat_iovec ciov;
ciovs = (struct compat_iovec __user *) arg;
if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov)))
return -EFAULT;
dst->iov_base = u64_to_user_ptr((u64)ciov.iov_base);
dst->iov_len = ciov.iov_len;
return 0;
}
#endif
src = (struct iovec __user *) arg;
if (copy_from_user(dst, &src[index], sizeof(*dst)))
return -EFAULT;
return 0;
}
static int io_buffer_validate(struct iovec *iov)
{
unsigned long tmp, acct_len = iov->iov_len + (PAGE_SIZE - 1);
/*
* Don't impose further limits on the size and buffer
* constraints here, we'll -EINVAL later when IO is
* submitted if they are wrong.
*/
if (!iov->iov_base)
return iov->iov_len ? -EFAULT : 0;
if (!iov->iov_len)
return -EFAULT;
/* arbitrary limit, but we need something */
if (iov->iov_len > SZ_1G)
return -EFAULT;
if (check_add_overflow((unsigned long)iov->iov_base, acct_len, &tmp))
return -EOVERFLOW;
return 0;
}
static void io_buffer_unmap(struct io_ring_ctx *ctx, struct io_mapped_ubuf **slot)
{
struct io_mapped_ubuf *imu = *slot;
unsigned int i;
if (imu != &dummy_ubuf) {
for (i = 0; i < imu->nr_bvecs; i++)
unpin_user_page(imu->bvec[i].bv_page);
if (imu->acct_pages)
io_unaccount_mem(ctx, imu->acct_pages);
kvfree(imu);
}
*slot = NULL;
}
static void io_rsrc_put_work(struct io_rsrc_node *node)
{
struct io_rsrc_put *prsrc = &node->item;
if (prsrc->tag)
io_post_aux_cqe(node->ctx, prsrc->tag, 0, 0);
switch (node->type) {
case IORING_RSRC_FILE:
io_rsrc_file_put(node->ctx, prsrc);
break;
case IORING_RSRC_BUFFER:
io_rsrc_buf_put(node->ctx, prsrc);
break;
default:
WARN_ON_ONCE(1);
break;
}
}
void io_rsrc_node_destroy(struct io_ring_ctx *ctx, struct io_rsrc_node *node)
{
if (!io_alloc_cache_put(&ctx->rsrc_node_cache, &node->cache))
kfree(node);
}
void io_rsrc_node_ref_zero(struct io_rsrc_node *node)
__must_hold(&node->ctx->uring_lock)
{
struct io_ring_ctx *ctx = node->ctx;
while (!list_empty(&ctx->rsrc_ref_list)) {
node = list_first_entry(&ctx->rsrc_ref_list,
struct io_rsrc_node, node);
/* recycle ref nodes in order */
if (node->refs)
break;
list_del(&node->node);
if (likely(!node->empty))
io_rsrc_put_work(node);
io_rsrc_node_destroy(ctx, node);
}
if (list_empty(&ctx->rsrc_ref_list) && unlikely(ctx->rsrc_quiesce))
wake_up_all(&ctx->rsrc_quiesce_wq);
}
struct io_rsrc_node *io_rsrc_node_alloc(struct io_ring_ctx *ctx)
{
struct io_rsrc_node *ref_node;
struct io_cache_entry *entry;
entry = io_alloc_cache_get(&ctx->rsrc_node_cache);
if (entry) {
ref_node = container_of(entry, struct io_rsrc_node, cache);
} else {
ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL);
if (!ref_node)
return NULL;
}
ref_node->ctx = ctx;
ref_node->empty = 0;
ref_node->refs = 1;
return ref_node;
}
__cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data,
struct io_ring_ctx *ctx)
{
struct io_rsrc_node *backup;
DEFINE_WAIT(we);
int ret;
/* As We may drop ->uring_lock, other task may have started quiesce */
if (data->quiesce)
return -ENXIO;
backup = io_rsrc_node_alloc(ctx);
if (!backup)
return -ENOMEM;
ctx->rsrc_node->empty = true;
ctx->rsrc_node->type = -1;
list_add_tail(&ctx->rsrc_node->node, &ctx->rsrc_ref_list);
io_put_rsrc_node(ctx, ctx->rsrc_node);
ctx->rsrc_node = backup;
if (list_empty(&ctx->rsrc_ref_list))
return 0;
if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
atomic_set(&ctx->cq_wait_nr, 1);
smp_mb();
}
ctx->rsrc_quiesce++;
data->quiesce = true;
do {
prepare_to_wait(&ctx->rsrc_quiesce_wq, &we, TASK_INTERRUPTIBLE);
mutex_unlock(&ctx->uring_lock);
ret = io_run_task_work_sig(ctx);
if (ret < 0) {
mutex_lock(&ctx->uring_lock);
if (list_empty(&ctx->rsrc_ref_list))
ret = 0;
break;
}
schedule();
__set_current_state(TASK_RUNNING);
mutex_lock(&ctx->uring_lock);
ret = 0;
} while (!list_empty(&ctx->rsrc_ref_list));
finish_wait(&ctx->rsrc_quiesce_wq, &we);
data->quiesce = false;
ctx->rsrc_quiesce--;
if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
atomic_set(&ctx->cq_wait_nr, 0);
smp_mb();
}
return ret;
}
static void io_free_page_table(void **table, size_t size)
{
unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE);
for (i = 0; i < nr_tables; i++)
kfree(table[i]);
kfree(table);
}
static void io_rsrc_data_free(struct io_rsrc_data *data)
{
size_t size = data->nr * sizeof(data->tags[0][0]);
if (data->tags)
io_free_page_table((void **)data->tags, size);
kfree(data);
}
static __cold void **io_alloc_page_table(size_t size)
{
unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE);
size_t init_size = size;
void **table;
table = kcalloc(nr_tables, sizeof(*table), GFP_KERNEL_ACCOUNT);
if (!table)
return NULL;
for (i = 0; i < nr_tables; i++) {
unsigned int this_size = min_t(size_t, size, PAGE_SIZE);
table[i] = kzalloc(this_size, GFP_KERNEL_ACCOUNT);
if (!table[i]) {
io_free_page_table(table, init_size);
return NULL;
}
size -= this_size;
}
return table;
}
__cold static int io_rsrc_data_alloc(struct io_ring_ctx *ctx, int type,
u64 __user *utags,
unsigned nr, struct io_rsrc_data **pdata)
{
struct io_rsrc_data *data;
int ret = 0;
unsigned i;
data = kzalloc(sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->tags = (u64 **)io_alloc_page_table(nr * sizeof(data->tags[0][0]));
if (!data->tags) {
kfree(data);
return -ENOMEM;
}
data->nr = nr;
data->ctx = ctx;
data->rsrc_type = type;
if (utags) {
ret = -EFAULT;
for (i = 0; i < nr; i++) {
u64 *tag_slot = io_get_tag_slot(data, i);
if (copy_from_user(tag_slot, &utags[i],
sizeof(*tag_slot)))
goto fail;
}
}
*pdata = data;
return 0;
fail:
io_rsrc_data_free(data);
return ret;
}
static int __io_sqe_files_update(struct io_ring_ctx *ctx,
struct io_uring_rsrc_update2 *up,
unsigned nr_args)
{
u64 __user *tags = u64_to_user_ptr(up->tags);
__s32 __user *fds = u64_to_user_ptr(up->data);
struct io_rsrc_data *data = ctx->file_data;
struct io_fixed_file *file_slot;
int fd, i, err = 0;
unsigned int done;
if (!ctx->file_data)
return -ENXIO;
if (up->offset + nr_args > ctx->nr_user_files)
return -EINVAL;
for (done = 0; done < nr_args; done++) {
u64 tag = 0;
if ((tags && copy_from_user(&tag, &tags[done], sizeof(tag))) ||
copy_from_user(&fd, &fds[done], sizeof(fd))) {
err = -EFAULT;
break;
}
if ((fd == IORING_REGISTER_FILES_SKIP || fd == -1) && tag) {
err = -EINVAL;
break;
}
if (fd == IORING_REGISTER_FILES_SKIP)
continue;
i = array_index_nospec(up->offset + done, ctx->nr_user_files);
file_slot = io_fixed_file_slot(&ctx->file_table, i);
if (file_slot->file_ptr) {
err = io_queue_rsrc_removal(data, i,
io_slot_file(file_slot));
if (err)
break;
file_slot->file_ptr = 0;
io_file_bitmap_clear(&ctx->file_table, i);
}
if (fd != -1) {
struct file *file = fget(fd);
if (!file) {
err = -EBADF;
break;
}
/*
* Don't allow io_uring instances to be registered. If
* UNIX isn't enabled, then this causes a reference
* cycle and this instance can never get freed. If UNIX
* is enabled we'll handle it just fine, but there's
* still no point in allowing a ring fd as it doesn't
* support regular read/write anyway.
*/
if (io_is_uring_fops(file)) {
fput(file);
err = -EBADF;
break;
}
err = io_scm_file_account(ctx, file);
if (err) {
fput(file);
break;
}
*io_get_tag_slot(data, i) = tag;
io_fixed_file_set(file_slot, file);
io_file_bitmap_set(&ctx->file_table, i);
}
}
return done ? done : err;
}
static int __io_sqe_buffers_update(struct io_ring_ctx *ctx,
struct io_uring_rsrc_update2 *up,
unsigned int nr_args)
{
u64 __user *tags = u64_to_user_ptr(up->tags);
struct iovec iov, __user *iovs = u64_to_user_ptr(up->data);
struct page *last_hpage = NULL;
__u32 done;
int i, err;
if (!ctx->buf_data)
return -ENXIO;
if (up->offset + nr_args > ctx->nr_user_bufs)
return -EINVAL;
for (done = 0; done < nr_args; done++) {
struct io_mapped_ubuf *imu;
u64 tag = 0;
err = io_copy_iov(ctx, &iov, iovs, done);
if (err)
break;
if (tags && copy_from_user(&tag, &tags[done], sizeof(tag))) {
err = -EFAULT;
break;
}
err = io_buffer_validate(&iov);
if (err)
break;
if (!iov.iov_base && tag) {
err = -EINVAL;
break;
}
err = io_sqe_buffer_register(ctx, &iov, &imu, &last_hpage);
if (err)
break;
i = array_index_nospec(up->offset + done, ctx->nr_user_bufs);
if (ctx->user_bufs[i] != &dummy_ubuf) {
err = io_queue_rsrc_removal(ctx->buf_data, i,
ctx->user_bufs[i]);
if (unlikely(err)) {
io_buffer_unmap(ctx, &imu);
break;
}
ctx->user_bufs[i] = (struct io_mapped_ubuf *)&dummy_ubuf;
}
ctx->user_bufs[i] = imu;
*io_get_tag_slot(ctx->buf_data, i) = tag;
}
return done ? done : err;
}
static int __io_register_rsrc_update(struct io_ring_ctx *ctx, unsigned type,
struct io_uring_rsrc_update2 *up,
unsigned nr_args)
{
__u32 tmp;
lockdep_assert_held(&ctx->uring_lock);
if (check_add_overflow(up->offset, nr_args, &tmp))
return -EOVERFLOW;
switch (type) {
case IORING_RSRC_FILE:
return __io_sqe_files_update(ctx, up, nr_args);
case IORING_RSRC_BUFFER:
return __io_sqe_buffers_update(ctx, up, nr_args);
}
return -EINVAL;
}
int io_register_files_update(struct io_ring_ctx *ctx, void __user *arg,
unsigned nr_args)
{
struct io_uring_rsrc_update2 up;
if (!nr_args)
return -EINVAL;
memset(&up, 0, sizeof(up));
if (copy_from_user(&up, arg, sizeof(struct io_uring_rsrc_update)))
return -EFAULT;
if (up.resv || up.resv2)
return -EINVAL;
return __io_register_rsrc_update(ctx, IORING_RSRC_FILE, &up, nr_args);
}
int io_register_rsrc_update(struct io_ring_ctx *ctx, void __user *arg,
unsigned size, unsigned type)
{
struct io_uring_rsrc_update2 up;
if (size != sizeof(up))
return -EINVAL;
if (copy_from_user(&up, arg, sizeof(up)))
return -EFAULT;
if (!up.nr || up.resv || up.resv2)
return -EINVAL;
return __io_register_rsrc_update(ctx, type, &up, up.nr);
}
__cold int io_register_rsrc(struct io_ring_ctx *ctx, void __user *arg,
unsigned int size, unsigned int type)
{
struct io_uring_rsrc_register rr;
/* keep it extendible */
if (size != sizeof(rr))
return -EINVAL;
memset(&rr, 0, sizeof(rr));
if (copy_from_user(&rr, arg, size))
return -EFAULT;
if (!rr.nr || rr.resv2)
return -EINVAL;
if (rr.flags & ~IORING_RSRC_REGISTER_SPARSE)
return -EINVAL;
switch (type) {
case IORING_RSRC_FILE:
if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data)
break;
return io_sqe_files_register(ctx, u64_to_user_ptr(rr.data),
rr.nr, u64_to_user_ptr(rr.tags));
case IORING_RSRC_BUFFER:
if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data)
break;
return io_sqe_buffers_register(ctx, u64_to_user_ptr(rr.data),
rr.nr, u64_to_user_ptr(rr.tags));
}
return -EINVAL;
}
int io_files_update_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
return -EINVAL;
if (sqe->rw_flags || sqe->splice_fd_in)
return -EINVAL;
up->offset = READ_ONCE(sqe->off);
up->nr_args = READ_ONCE(sqe->len);
if (!up->nr_args)
return -EINVAL;
up->arg = READ_ONCE(sqe->addr);
return 0;
}
static int io_files_update_with_index_alloc(struct io_kiocb *req,
unsigned int issue_flags)
{
struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
__s32 __user *fds = u64_to_user_ptr(up->arg);
unsigned int done;
struct file *file;
int ret, fd;
if (!req->ctx->file_data)
return -ENXIO;
for (done = 0; done < up->nr_args; done++) {
if (copy_from_user(&fd, &fds[done], sizeof(fd))) {
ret = -EFAULT;
break;
}
file = fget(fd);
if (!file) {
ret = -EBADF;
break;
}
ret = io_fixed_fd_install(req, issue_flags, file,
IORING_FILE_INDEX_ALLOC);
if (ret < 0)
break;
if (copy_to_user(&fds[done], &ret, sizeof(ret))) {
__io_close_fixed(req->ctx, issue_flags, ret);
ret = -EFAULT;
break;
}
}
if (done)
return done;
return ret;
}
int io_files_update(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
struct io_ring_ctx *ctx = req->ctx;
struct io_uring_rsrc_update2 up2;
int ret;
up2.offset = up->offset;
up2.data = up->arg;
up2.nr = 0;
up2.tags = 0;
up2.resv = 0;
up2.resv2 = 0;
if (up->offset == IORING_FILE_INDEX_ALLOC) {
ret = io_files_update_with_index_alloc(req, issue_flags);
} else {
io_ring_submit_lock(ctx, issue_flags);
ret = __io_register_rsrc_update(ctx, IORING_RSRC_FILE,
&up2, up->nr_args);
io_ring_submit_unlock(ctx, issue_flags);
}
if (ret < 0)
req_set_fail(req);
io_req_set_res(req, ret, 0);
return IOU_OK;
}
int io_queue_rsrc_removal(struct io_rsrc_data *data, unsigned idx, void *rsrc)
{
struct io_ring_ctx *ctx = data->ctx;
struct io_rsrc_node *node = ctx->rsrc_node;
u64 *tag_slot = io_get_tag_slot(data, idx);
ctx->rsrc_node = io_rsrc_node_alloc(ctx);
if (unlikely(!ctx->rsrc_node)) {
ctx->rsrc_node = node;
return -ENOMEM;
}
node->item.rsrc = rsrc;
node->type = data->rsrc_type;
node->item.tag = *tag_slot;
*tag_slot = 0;
list_add_tail(&node->node, &ctx->rsrc_ref_list);
io_put_rsrc_node(ctx, node);
return 0;
}
void __io_sqe_files_unregister(struct io_ring_ctx *ctx)
{
int i;
for (i = 0; i < ctx->nr_user_files; i++) {
struct file *file = io_file_from_index(&ctx->file_table, i);
/* skip scm accounted files, they'll be freed by ->ring_sock */
if (!file || io_file_need_scm(file))
continue;
io_file_bitmap_clear(&ctx->file_table, i);
fput(file);
}
#if defined(CONFIG_UNIX)
if (ctx->ring_sock) {
struct sock *sock = ctx->ring_sock->sk;
struct sk_buff *skb;
while ((skb = skb_dequeue(&sock->sk_receive_queue)) != NULL)
kfree_skb(skb);
}
#endif
io_free_file_tables(&ctx->file_table);
io_file_table_set_alloc_range(ctx, 0, 0);
io_rsrc_data_free(ctx->file_data);
ctx->file_data = NULL;
ctx->nr_user_files = 0;
}
int io_sqe_files_unregister(struct io_ring_ctx *ctx)
{
unsigned nr = ctx->nr_user_files;
int ret;
if (!ctx->file_data)
return -ENXIO;
/*
* Quiesce may unlock ->uring_lock, and while it's not held
* prevent new requests using the table.
*/
ctx->nr_user_files = 0;
ret = io_rsrc_ref_quiesce(ctx->file_data, ctx);
ctx->nr_user_files = nr;
if (!ret)
__io_sqe_files_unregister(ctx);
return ret;
}
/*
* Ensure the UNIX gc is aware of our file set, so we are certain that
* the io_uring can be safely unregistered on process exit, even if we have
* loops in the file referencing. We account only files that can hold other
* files because otherwise they can't form a loop and so are not interesting
* for GC.
*/
int __io_scm_file_account(struct io_ring_ctx *ctx, struct file *file)
{
#if defined(CONFIG_UNIX)
struct sock *sk = ctx->ring_sock->sk;
struct sk_buff_head *head = &sk->sk_receive_queue;
struct scm_fp_list *fpl;
struct sk_buff *skb;
if (likely(!io_file_need_scm(file)))
return 0;
/*
* See if we can merge this file into an existing skb SCM_RIGHTS
* file set. If there's no room, fall back to allocating a new skb
* and filling it in.
*/
spin_lock_irq(&head->lock);
skb = skb_peek(head);
if (skb && UNIXCB(skb).fp->count < SCM_MAX_FD)
__skb_unlink(skb, head);
else
skb = NULL;
spin_unlock_irq(&head->lock);
if (!skb) {
fpl = kzalloc(sizeof(*fpl), GFP_KERNEL);
if (!fpl)
return -ENOMEM;
skb = alloc_skb(0, GFP_KERNEL);
if (!skb) {
kfree(fpl);
return -ENOMEM;
}
fpl->user = get_uid(current_user());
fpl->max = SCM_MAX_FD;
fpl->count = 0;
UNIXCB(skb).fp = fpl;
skb->sk = sk;
skb->destructor = io_uring_destruct_scm;
refcount_add(skb->truesize, &sk->sk_wmem_alloc);
}
fpl = UNIXCB(skb).fp;
fpl->fp[fpl->count++] = get_file(file);
unix_inflight(fpl->user, file);
skb_queue_head(head, skb);
fput(file);
#endif
return 0;
}
static __cold void io_rsrc_file_scm_put(struct io_ring_ctx *ctx, struct file *file)
{
#if defined(CONFIG_UNIX)
struct sock *sock = ctx->ring_sock->sk;
struct sk_buff_head list, *head = &sock->sk_receive_queue;
struct sk_buff *skb;
int i;
__skb_queue_head_init(&list);
/*
* Find the skb that holds this file in its SCM_RIGHTS. When found,
* remove this entry and rearrange the file array.
*/
skb = skb_dequeue(head);
while (skb) {
struct scm_fp_list *fp;
fp = UNIXCB(skb).fp;
for (i = 0; i < fp->count; i++) {
int left;
if (fp->fp[i] != file)
continue;
unix_notinflight(fp->user, fp->fp[i]);
left = fp->count - 1 - i;
if (left) {
memmove(&fp->fp[i], &fp->fp[i + 1],
left * sizeof(struct file *));
}
fp->count--;
if (!fp->count) {
kfree_skb(skb);
skb = NULL;
} else {
__skb_queue_tail(&list, skb);
}
fput(file);
file = NULL;
break;
}
if (!file)
break;
__skb_queue_tail(&list, skb);
skb = skb_dequeue(head);
}
if (skb_peek(&list)) {
spin_lock_irq(&head->lock);
while ((skb = __skb_dequeue(&list)) != NULL)
__skb_queue_tail(head, skb);
spin_unlock_irq(&head->lock);
}
#endif
}
static void io_rsrc_file_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc)
{
struct file *file = prsrc->file;
if (likely(!io_file_need_scm(file)))
fput(file);
else
io_rsrc_file_scm_put(ctx, file);
}
int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
unsigned nr_args, u64 __user *tags)
{
__s32 __user *fds = (__s32 __user *) arg;
struct file *file;
int fd, ret;
unsigned i;
if (ctx->file_data)
return -EBUSY;
if (!nr_args)
return -EINVAL;
if (nr_args > IORING_MAX_FIXED_FILES)
return -EMFILE;
if (nr_args > rlimit(RLIMIT_NOFILE))
return -EMFILE;
ret = io_rsrc_data_alloc(ctx, IORING_RSRC_FILE, tags, nr_args,
&ctx->file_data);
if (ret)
return ret;
if (!io_alloc_file_tables(&ctx->file_table, nr_args)) {
io_rsrc_data_free(ctx->file_data);
ctx->file_data = NULL;
return -ENOMEM;
}
for (i = 0; i < nr_args; i++, ctx->nr_user_files++) {
struct io_fixed_file *file_slot;
if (fds && copy_from_user(&fd, &fds[i], sizeof(fd))) {
ret = -EFAULT;
goto fail;
}
/* allow sparse sets */
if (!fds || fd == -1) {
ret = -EINVAL;
if (unlikely(*io_get_tag_slot(ctx->file_data, i)))
goto fail;
continue;
}
file = fget(fd);
ret = -EBADF;
if (unlikely(!file))
goto fail;
/*
* Don't allow io_uring instances to be registered. If UNIX
* isn't enabled, then this causes a reference cycle and this
* instance can never get freed. If UNIX is enabled we'll
* handle it just fine, but there's still no point in allowing
* a ring fd as it doesn't support regular read/write anyway.
*/
if (io_is_uring_fops(file)) {
fput(file);
goto fail;
}
ret = io_scm_file_account(ctx, file);
if (ret) {
fput(file);
goto fail;
}
file_slot = io_fixed_file_slot(&ctx->file_table, i);
io_fixed_file_set(file_slot, file);
io_file_bitmap_set(&ctx->file_table, i);
}
/* default it to the whole table */
io_file_table_set_alloc_range(ctx, 0, ctx->nr_user_files);
return 0;
fail:
__io_sqe_files_unregister(ctx);
return ret;
}
static void io_rsrc_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc)
{
io_buffer_unmap(ctx, &prsrc->buf);
prsrc->buf = NULL;
}
void __io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
{
unsigned int i;
for (i = 0; i < ctx->nr_user_bufs; i++)
io_buffer_unmap(ctx, &ctx->user_bufs[i]);
kfree(ctx->user_bufs);
io_rsrc_data_free(ctx->buf_data);
ctx->user_bufs = NULL;
ctx->buf_data = NULL;
ctx->nr_user_bufs = 0;
}
int io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
{
unsigned nr = ctx->nr_user_bufs;
int ret;
if (!ctx->buf_data)
return -ENXIO;
/*
* Quiesce may unlock ->uring_lock, and while it's not held
* prevent new requests using the table.
*/
ctx->nr_user_bufs = 0;
ret = io_rsrc_ref_quiesce(ctx->buf_data, ctx);
ctx->nr_user_bufs = nr;
if (!ret)
__io_sqe_buffers_unregister(ctx);
return ret;
}
/*
* Not super efficient, but this is just a registration time. And we do cache
* the last compound head, so generally we'll only do a full search if we don't
* match that one.
*
* We check if the given compound head page has already been accounted, to
* avoid double accounting it. This allows us to account the full size of the
* page, not just the constituent pages of a huge page.
*/
static bool headpage_already_acct(struct io_ring_ctx *ctx, struct page **pages,
int nr_pages, struct page *hpage)
{
int i, j;
/* check current page array */
for (i = 0; i < nr_pages; i++) {
if (!PageCompound(pages[i]))
continue;
if (compound_head(pages[i]) == hpage)
return true;
}
/* check previously registered pages */
for (i = 0; i < ctx->nr_user_bufs; i++) {
struct io_mapped_ubuf *imu = ctx->user_bufs[i];
for (j = 0; j < imu->nr_bvecs; j++) {
if (!PageCompound(imu->bvec[j].bv_page))
continue;
if (compound_head(imu->bvec[j].bv_page) == hpage)
return true;
}
}
return false;
}
static int io_buffer_account_pin(struct io_ring_ctx *ctx, struct page **pages,
int nr_pages, struct io_mapped_ubuf *imu,
struct page **last_hpage)
{
int i, ret;
imu->acct_pages = 0;
for (i = 0; i < nr_pages; i++) {
if (!PageCompound(pages[i])) {
imu->acct_pages++;
} else {
struct page *hpage;
hpage = compound_head(pages[i]);
if (hpage == *last_hpage)
continue;
*last_hpage = hpage;
if (headpage_already_acct(ctx, pages, i, hpage))
continue;
imu->acct_pages += page_size(hpage) >> PAGE_SHIFT;
}
}
if (!imu->acct_pages)
return 0;
ret = io_account_mem(ctx, imu->acct_pages);
if (ret)
imu->acct_pages = 0;
return ret;
}
struct page **io_pin_pages(unsigned long ubuf, unsigned long len, int *npages)
{
unsigned long start, end, nr_pages;
struct page **pages = NULL;
int pret, ret = -ENOMEM;
end = (ubuf + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
start = ubuf >> PAGE_SHIFT;
nr_pages = end - start;
pages = kvmalloc_array(nr_pages, sizeof(struct page *), GFP_KERNEL);
if (!pages)
goto done;
ret = 0;
mmap_read_lock(current->mm);
pret = pin_user_pages(ubuf, nr_pages, FOLL_WRITE | FOLL_LONGTERM,
pages);
if (pret == nr_pages)
*npages = nr_pages;
else
ret = pret < 0 ? pret : -EFAULT;
mmap_read_unlock(current->mm);
if (ret) {
/* if we did partial map, release any pages we did get */
if (pret > 0)
unpin_user_pages(pages, pret);
goto done;
}
ret = 0;
done:
if (ret < 0) {
kvfree(pages);
pages = ERR_PTR(ret);
}
return pages;
}
static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
struct io_mapped_ubuf **pimu,
struct page **last_hpage)
{
struct io_mapped_ubuf *imu = NULL;
struct page **pages = NULL;
unsigned long off;
size_t size;
int ret, nr_pages, i;
struct folio *folio = NULL;
*pimu = (struct io_mapped_ubuf *)&dummy_ubuf;
if (!iov->iov_base)
return 0;
ret = -ENOMEM;
pages = io_pin_pages((unsigned long) iov->iov_base, iov->iov_len,
&nr_pages);
if (IS_ERR(pages)) {
ret = PTR_ERR(pages);
pages = NULL;
goto done;
}
/* If it's a huge page, try to coalesce them into a single bvec entry */
if (nr_pages > 1) {
folio = page_folio(pages[0]);
for (i = 1; i < nr_pages; i++) {
/*
* Pages must be consecutive and on the same folio for
* this to work
*/
if (page_folio(pages[i]) != folio ||
pages[i] != pages[i - 1] + 1) {
folio = NULL;
break;
}
}
if (folio) {
/*
* The pages are bound to the folio, it doesn't
* actually unpin them but drops all but one reference,
* which is usually put down by io_buffer_unmap().
* Note, needs a better helper.
*/
unpin_user_pages(&pages[1], nr_pages - 1);
nr_pages = 1;
}
}
imu = kvmalloc(struct_size(imu, bvec, nr_pages), GFP_KERNEL);
if (!imu)
goto done;
ret = io_buffer_account_pin(ctx, pages, nr_pages, imu, last_hpage);
if (ret) {
unpin_user_pages(pages, nr_pages);
goto done;
}
off = (unsigned long) iov->iov_base & ~PAGE_MASK;
size = iov->iov_len;
/* store original address for later verification */
imu->ubuf = (unsigned long) iov->iov_base;
imu->ubuf_end = imu->ubuf + iov->iov_len;
imu->nr_bvecs = nr_pages;
*pimu = imu;
ret = 0;
if (folio) {
bvec_set_page(&imu->bvec[0], pages[0], size, off);
goto done;
}
for (i = 0; i < nr_pages; i++) {
size_t vec_len;
vec_len = min_t(size_t, size, PAGE_SIZE - off);
bvec_set_page(&imu->bvec[i], pages[i], vec_len, off);
off = 0;
size -= vec_len;
}
done:
if (ret)
kvfree(imu);
kvfree(pages);
return ret;
}
static int io_buffers_map_alloc(struct io_ring_ctx *ctx, unsigned int nr_args)
{
ctx->user_bufs = kcalloc(nr_args, sizeof(*ctx->user_bufs), GFP_KERNEL);
return ctx->user_bufs ? 0 : -ENOMEM;
}
int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
unsigned int nr_args, u64 __user *tags)
{
struct page *last_hpage = NULL;
struct io_rsrc_data *data;
int i, ret;
struct iovec iov;
BUILD_BUG_ON(IORING_MAX_REG_BUFFERS >= (1u << 16));
if (ctx->user_bufs)
return -EBUSY;
if (!nr_args || nr_args > IORING_MAX_REG_BUFFERS)
return -EINVAL;
ret = io_rsrc_data_alloc(ctx, IORING_RSRC_BUFFER, tags, nr_args, &data);
if (ret)
return ret;
ret = io_buffers_map_alloc(ctx, nr_args);
if (ret) {
io_rsrc_data_free(data);
return ret;
}
for (i = 0; i < nr_args; i++, ctx->nr_user_bufs++) {
if (arg) {
ret = io_copy_iov(ctx, &iov, arg, i);
if (ret)
break;
ret = io_buffer_validate(&iov);
if (ret)
break;
} else {
memset(&iov, 0, sizeof(iov));
}
if (!iov.iov_base && *io_get_tag_slot(data, i)) {
ret = -EINVAL;
break;
}
ret = io_sqe_buffer_register(ctx, &iov, &ctx->user_bufs[i],
&last_hpage);
if (ret)
break;
}
WARN_ON_ONCE(ctx->buf_data);
ctx->buf_data = data;
if (ret)
__io_sqe_buffers_unregister(ctx);
return ret;
}
int io_import_fixed(int ddir, struct iov_iter *iter,
struct io_mapped_ubuf *imu,
u64 buf_addr, size_t len)
{
u64 buf_end;
size_t offset;
if (WARN_ON_ONCE(!imu))
return -EFAULT;
if (unlikely(check_add_overflow(buf_addr, (u64)len, &buf_end)))
return -EFAULT;
/* not inside the mapped region */
if (unlikely(buf_addr < imu->ubuf || buf_end > imu->ubuf_end))
return -EFAULT;
/*
* Might not be a start of buffer, set size appropriately
* and advance us to the beginning.
*/
offset = buf_addr - imu->ubuf;
iov_iter_bvec(iter, ddir, imu->bvec, imu->nr_bvecs, offset + len);
if (offset) {
/*
* Don't use iov_iter_advance() here, as it's really slow for
* using the latter parts of a big fixed buffer - it iterates
* over each segment manually. We can cheat a bit here, because
* we know that:
*
* 1) it's a BVEC iter, we set it up
* 2) all bvecs are PAGE_SIZE in size, except potentially the
* first and last bvec
*
* So just find our index, and adjust the iterator afterwards.
* If the offset is within the first bvec (or the whole first
* bvec, just use iov_iter_advance(). This makes it easier
* since we can just skip the first segment, which may not
* be PAGE_SIZE aligned.
*/
const struct bio_vec *bvec = imu->bvec;
if (offset <= bvec->bv_len) {
/*
* Note, huge pages buffers consists of one large
* bvec entry and should always go this way. The other
* branch doesn't expect non PAGE_SIZE'd chunks.
*/
iter->bvec = bvec;
iter->nr_segs = bvec->bv_len;
iter->count -= offset;
iter->iov_offset = offset;
} else {
unsigned long seg_skip;
/* skip first vec */
offset -= bvec->bv_len;
seg_skip = 1 + (offset >> PAGE_SHIFT);
iter->bvec = bvec + seg_skip;
iter->nr_segs -= seg_skip;
iter->count -= bvec->bv_len + offset;
iter->iov_offset = offset & ~PAGE_MASK;
}
}
return 0;
}
| linux-master | io_uring/rsrc.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Basic worker thread pool for io_uring
*
* Copyright (C) 2019 Jens Axboe
*
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/sched/signal.h>
#include <linux/percpu.h>
#include <linux/slab.h>
#include <linux/rculist_nulls.h>
#include <linux/cpu.h>
#include <linux/task_work.h>
#include <linux/audit.h>
#include <linux/mmu_context.h>
#include <uapi/linux/io_uring.h>
#include "io-wq.h"
#include "slist.h"
#include "io_uring.h"
#define WORKER_IDLE_TIMEOUT (5 * HZ)
enum {
IO_WORKER_F_UP = 1, /* up and active */
IO_WORKER_F_RUNNING = 2, /* account as running */
IO_WORKER_F_FREE = 4, /* worker on free list */
IO_WORKER_F_BOUND = 8, /* is doing bounded work */
};
enum {
IO_WQ_BIT_EXIT = 0, /* wq exiting */
};
enum {
IO_ACCT_STALLED_BIT = 0, /* stalled on hash */
};
/*
* One for each thread in a wq pool
*/
struct io_worker {
refcount_t ref;
unsigned flags;
struct hlist_nulls_node nulls_node;
struct list_head all_list;
struct task_struct *task;
struct io_wq *wq;
struct io_wq_work *cur_work;
struct io_wq_work *next_work;
raw_spinlock_t lock;
struct completion ref_done;
unsigned long create_state;
struct callback_head create_work;
int create_index;
union {
struct rcu_head rcu;
struct work_struct work;
};
};
#if BITS_PER_LONG == 64
#define IO_WQ_HASH_ORDER 6
#else
#define IO_WQ_HASH_ORDER 5
#endif
#define IO_WQ_NR_HASH_BUCKETS (1u << IO_WQ_HASH_ORDER)
struct io_wq_acct {
unsigned nr_workers;
unsigned max_workers;
int index;
atomic_t nr_running;
raw_spinlock_t lock;
struct io_wq_work_list work_list;
unsigned long flags;
};
enum {
IO_WQ_ACCT_BOUND,
IO_WQ_ACCT_UNBOUND,
IO_WQ_ACCT_NR,
};
/*
* Per io_wq state
*/
struct io_wq {
unsigned long state;
free_work_fn *free_work;
io_wq_work_fn *do_work;
struct io_wq_hash *hash;
atomic_t worker_refs;
struct completion worker_done;
struct hlist_node cpuhp_node;
struct task_struct *task;
struct io_wq_acct acct[IO_WQ_ACCT_NR];
/* lock protects access to elements below */
raw_spinlock_t lock;
struct hlist_nulls_head free_list;
struct list_head all_list;
struct wait_queue_entry wait;
struct io_wq_work *hash_tail[IO_WQ_NR_HASH_BUCKETS];
cpumask_var_t cpu_mask;
};
static enum cpuhp_state io_wq_online;
struct io_cb_cancel_data {
work_cancel_fn *fn;
void *data;
int nr_running;
int nr_pending;
bool cancel_all;
};
static bool create_io_worker(struct io_wq *wq, int index);
static void io_wq_dec_running(struct io_worker *worker);
static bool io_acct_cancel_pending_work(struct io_wq *wq,
struct io_wq_acct *acct,
struct io_cb_cancel_data *match);
static void create_worker_cb(struct callback_head *cb);
static void io_wq_cancel_tw_create(struct io_wq *wq);
static bool io_worker_get(struct io_worker *worker)
{
return refcount_inc_not_zero(&worker->ref);
}
static void io_worker_release(struct io_worker *worker)
{
if (refcount_dec_and_test(&worker->ref))
complete(&worker->ref_done);
}
static inline struct io_wq_acct *io_get_acct(struct io_wq *wq, bool bound)
{
return &wq->acct[bound ? IO_WQ_ACCT_BOUND : IO_WQ_ACCT_UNBOUND];
}
static inline struct io_wq_acct *io_work_get_acct(struct io_wq *wq,
struct io_wq_work *work)
{
return io_get_acct(wq, !(work->flags & IO_WQ_WORK_UNBOUND));
}
static inline struct io_wq_acct *io_wq_get_acct(struct io_worker *worker)
{
return io_get_acct(worker->wq, worker->flags & IO_WORKER_F_BOUND);
}
static void io_worker_ref_put(struct io_wq *wq)
{
if (atomic_dec_and_test(&wq->worker_refs))
complete(&wq->worker_done);
}
bool io_wq_worker_stopped(void)
{
struct io_worker *worker = current->worker_private;
if (WARN_ON_ONCE(!io_wq_current_is_worker()))
return true;
return test_bit(IO_WQ_BIT_EXIT, &worker->wq->state);
}
static void io_worker_cancel_cb(struct io_worker *worker)
{
struct io_wq_acct *acct = io_wq_get_acct(worker);
struct io_wq *wq = worker->wq;
atomic_dec(&acct->nr_running);
raw_spin_lock(&wq->lock);
acct->nr_workers--;
raw_spin_unlock(&wq->lock);
io_worker_ref_put(wq);
clear_bit_unlock(0, &worker->create_state);
io_worker_release(worker);
}
static bool io_task_worker_match(struct callback_head *cb, void *data)
{
struct io_worker *worker;
if (cb->func != create_worker_cb)
return false;
worker = container_of(cb, struct io_worker, create_work);
return worker == data;
}
static void io_worker_exit(struct io_worker *worker)
{
struct io_wq *wq = worker->wq;
while (1) {
struct callback_head *cb = task_work_cancel_match(wq->task,
io_task_worker_match, worker);
if (!cb)
break;
io_worker_cancel_cb(worker);
}
io_worker_release(worker);
wait_for_completion(&worker->ref_done);
raw_spin_lock(&wq->lock);
if (worker->flags & IO_WORKER_F_FREE)
hlist_nulls_del_rcu(&worker->nulls_node);
list_del_rcu(&worker->all_list);
raw_spin_unlock(&wq->lock);
io_wq_dec_running(worker);
/*
* this worker is a goner, clear ->worker_private to avoid any
* inc/dec running calls that could happen as part of exit from
* touching 'worker'.
*/
current->worker_private = NULL;
kfree_rcu(worker, rcu);
io_worker_ref_put(wq);
do_exit(0);
}
static inline bool __io_acct_run_queue(struct io_wq_acct *acct)
{
return !test_bit(IO_ACCT_STALLED_BIT, &acct->flags) &&
!wq_list_empty(&acct->work_list);
}
/*
* If there's work to do, returns true with acct->lock acquired. If not,
* returns false with no lock held.
*/
static inline bool io_acct_run_queue(struct io_wq_acct *acct)
__acquires(&acct->lock)
{
raw_spin_lock(&acct->lock);
if (__io_acct_run_queue(acct))
return true;
raw_spin_unlock(&acct->lock);
return false;
}
/*
* Check head of free list for an available worker. If one isn't available,
* caller must create one.
*/
static bool io_wq_activate_free_worker(struct io_wq *wq,
struct io_wq_acct *acct)
__must_hold(RCU)
{
struct hlist_nulls_node *n;
struct io_worker *worker;
/*
* Iterate free_list and see if we can find an idle worker to
* activate. If a given worker is on the free_list but in the process
* of exiting, keep trying.
*/
hlist_nulls_for_each_entry_rcu(worker, n, &wq->free_list, nulls_node) {
if (!io_worker_get(worker))
continue;
if (io_wq_get_acct(worker) != acct) {
io_worker_release(worker);
continue;
}
/*
* If the worker is already running, it's either already
* starting work or finishing work. In either case, if it does
* to go sleep, we'll kick off a new task for this work anyway.
*/
wake_up_process(worker->task);
io_worker_release(worker);
return true;
}
return false;
}
/*
* We need a worker. If we find a free one, we're good. If not, and we're
* below the max number of workers, create one.
*/
static bool io_wq_create_worker(struct io_wq *wq, struct io_wq_acct *acct)
{
/*
* Most likely an attempt to queue unbounded work on an io_wq that
* wasn't setup with any unbounded workers.
*/
if (unlikely(!acct->max_workers))
pr_warn_once("io-wq is not configured for unbound workers");
raw_spin_lock(&wq->lock);
if (acct->nr_workers >= acct->max_workers) {
raw_spin_unlock(&wq->lock);
return true;
}
acct->nr_workers++;
raw_spin_unlock(&wq->lock);
atomic_inc(&acct->nr_running);
atomic_inc(&wq->worker_refs);
return create_io_worker(wq, acct->index);
}
static void io_wq_inc_running(struct io_worker *worker)
{
struct io_wq_acct *acct = io_wq_get_acct(worker);
atomic_inc(&acct->nr_running);
}
static void create_worker_cb(struct callback_head *cb)
{
struct io_worker *worker;
struct io_wq *wq;
struct io_wq_acct *acct;
bool do_create = false;
worker = container_of(cb, struct io_worker, create_work);
wq = worker->wq;
acct = &wq->acct[worker->create_index];
raw_spin_lock(&wq->lock);
if (acct->nr_workers < acct->max_workers) {
acct->nr_workers++;
do_create = true;
}
raw_spin_unlock(&wq->lock);
if (do_create) {
create_io_worker(wq, worker->create_index);
} else {
atomic_dec(&acct->nr_running);
io_worker_ref_put(wq);
}
clear_bit_unlock(0, &worker->create_state);
io_worker_release(worker);
}
static bool io_queue_worker_create(struct io_worker *worker,
struct io_wq_acct *acct,
task_work_func_t func)
{
struct io_wq *wq = worker->wq;
/* raced with exit, just ignore create call */
if (test_bit(IO_WQ_BIT_EXIT, &wq->state))
goto fail;
if (!io_worker_get(worker))
goto fail;
/*
* create_state manages ownership of create_work/index. We should
* only need one entry per worker, as the worker going to sleep
* will trigger the condition, and waking will clear it once it
* runs the task_work.
*/
if (test_bit(0, &worker->create_state) ||
test_and_set_bit_lock(0, &worker->create_state))
goto fail_release;
atomic_inc(&wq->worker_refs);
init_task_work(&worker->create_work, func);
worker->create_index = acct->index;
if (!task_work_add(wq->task, &worker->create_work, TWA_SIGNAL)) {
/*
* EXIT may have been set after checking it above, check after
* adding the task_work and remove any creation item if it is
* now set. wq exit does that too, but we can have added this
* work item after we canceled in io_wq_exit_workers().
*/
if (test_bit(IO_WQ_BIT_EXIT, &wq->state))
io_wq_cancel_tw_create(wq);
io_worker_ref_put(wq);
return true;
}
io_worker_ref_put(wq);
clear_bit_unlock(0, &worker->create_state);
fail_release:
io_worker_release(worker);
fail:
atomic_dec(&acct->nr_running);
io_worker_ref_put(wq);
return false;
}
static void io_wq_dec_running(struct io_worker *worker)
{
struct io_wq_acct *acct = io_wq_get_acct(worker);
struct io_wq *wq = worker->wq;
if (!(worker->flags & IO_WORKER_F_UP))
return;
if (!atomic_dec_and_test(&acct->nr_running))
return;
if (!io_acct_run_queue(acct))
return;
raw_spin_unlock(&acct->lock);
atomic_inc(&acct->nr_running);
atomic_inc(&wq->worker_refs);
io_queue_worker_create(worker, acct, create_worker_cb);
}
/*
* Worker will start processing some work. Move it to the busy list, if
* it's currently on the freelist
*/
static void __io_worker_busy(struct io_wq *wq, struct io_worker *worker)
{
if (worker->flags & IO_WORKER_F_FREE) {
worker->flags &= ~IO_WORKER_F_FREE;
raw_spin_lock(&wq->lock);
hlist_nulls_del_init_rcu(&worker->nulls_node);
raw_spin_unlock(&wq->lock);
}
}
/*
* No work, worker going to sleep. Move to freelist.
*/
static void __io_worker_idle(struct io_wq *wq, struct io_worker *worker)
__must_hold(wq->lock)
{
if (!(worker->flags & IO_WORKER_F_FREE)) {
worker->flags |= IO_WORKER_F_FREE;
hlist_nulls_add_head_rcu(&worker->nulls_node, &wq->free_list);
}
}
static inline unsigned int io_get_work_hash(struct io_wq_work *work)
{
return work->flags >> IO_WQ_HASH_SHIFT;
}
static bool io_wait_on_hash(struct io_wq *wq, unsigned int hash)
{
bool ret = false;
spin_lock_irq(&wq->hash->wait.lock);
if (list_empty(&wq->wait.entry)) {
__add_wait_queue(&wq->hash->wait, &wq->wait);
if (!test_bit(hash, &wq->hash->map)) {
__set_current_state(TASK_RUNNING);
list_del_init(&wq->wait.entry);
ret = true;
}
}
spin_unlock_irq(&wq->hash->wait.lock);
return ret;
}
static struct io_wq_work *io_get_next_work(struct io_wq_acct *acct,
struct io_worker *worker)
__must_hold(acct->lock)
{
struct io_wq_work_node *node, *prev;
struct io_wq_work *work, *tail;
unsigned int stall_hash = -1U;
struct io_wq *wq = worker->wq;
wq_list_for_each(node, prev, &acct->work_list) {
unsigned int hash;
work = container_of(node, struct io_wq_work, list);
/* not hashed, can run anytime */
if (!io_wq_is_hashed(work)) {
wq_list_del(&acct->work_list, node, prev);
return work;
}
hash = io_get_work_hash(work);
/* all items with this hash lie in [work, tail] */
tail = wq->hash_tail[hash];
/* hashed, can run if not already running */
if (!test_and_set_bit(hash, &wq->hash->map)) {
wq->hash_tail[hash] = NULL;
wq_list_cut(&acct->work_list, &tail->list, prev);
return work;
}
if (stall_hash == -1U)
stall_hash = hash;
/* fast forward to a next hash, for-each will fix up @prev */
node = &tail->list;
}
if (stall_hash != -1U) {
bool unstalled;
/*
* Set this before dropping the lock to avoid racing with new
* work being added and clearing the stalled bit.
*/
set_bit(IO_ACCT_STALLED_BIT, &acct->flags);
raw_spin_unlock(&acct->lock);
unstalled = io_wait_on_hash(wq, stall_hash);
raw_spin_lock(&acct->lock);
if (unstalled) {
clear_bit(IO_ACCT_STALLED_BIT, &acct->flags);
if (wq_has_sleeper(&wq->hash->wait))
wake_up(&wq->hash->wait);
}
}
return NULL;
}
static void io_assign_current_work(struct io_worker *worker,
struct io_wq_work *work)
{
if (work) {
io_run_task_work();
cond_resched();
}
raw_spin_lock(&worker->lock);
worker->cur_work = work;
worker->next_work = NULL;
raw_spin_unlock(&worker->lock);
}
/*
* Called with acct->lock held, drops it before returning
*/
static void io_worker_handle_work(struct io_wq_acct *acct,
struct io_worker *worker)
__releases(&acct->lock)
{
struct io_wq *wq = worker->wq;
bool do_kill = test_bit(IO_WQ_BIT_EXIT, &wq->state);
do {
struct io_wq_work *work;
/*
* If we got some work, mark us as busy. If we didn't, but
* the list isn't empty, it means we stalled on hashed work.
* Mark us stalled so we don't keep looking for work when we
* can't make progress, any work completion or insertion will
* clear the stalled flag.
*/
work = io_get_next_work(acct, worker);
raw_spin_unlock(&acct->lock);
if (work) {
__io_worker_busy(wq, worker);
/*
* Make sure cancelation can find this, even before
* it becomes the active work. That avoids a window
* where the work has been removed from our general
* work list, but isn't yet discoverable as the
* current work item for this worker.
*/
raw_spin_lock(&worker->lock);
worker->next_work = work;
raw_spin_unlock(&worker->lock);
} else {
break;
}
io_assign_current_work(worker, work);
__set_current_state(TASK_RUNNING);
/* handle a whole dependent link */
do {
struct io_wq_work *next_hashed, *linked;
unsigned int hash = io_get_work_hash(work);
next_hashed = wq_next_work(work);
if (unlikely(do_kill) && (work->flags & IO_WQ_WORK_UNBOUND))
work->flags |= IO_WQ_WORK_CANCEL;
wq->do_work(work);
io_assign_current_work(worker, NULL);
linked = wq->free_work(work);
work = next_hashed;
if (!work && linked && !io_wq_is_hashed(linked)) {
work = linked;
linked = NULL;
}
io_assign_current_work(worker, work);
if (linked)
io_wq_enqueue(wq, linked);
if (hash != -1U && !next_hashed) {
/* serialize hash clear with wake_up() */
spin_lock_irq(&wq->hash->wait.lock);
clear_bit(hash, &wq->hash->map);
clear_bit(IO_ACCT_STALLED_BIT, &acct->flags);
spin_unlock_irq(&wq->hash->wait.lock);
if (wq_has_sleeper(&wq->hash->wait))
wake_up(&wq->hash->wait);
}
} while (work);
if (!__io_acct_run_queue(acct))
break;
raw_spin_lock(&acct->lock);
} while (1);
}
static int io_wq_worker(void *data)
{
struct io_worker *worker = data;
struct io_wq_acct *acct = io_wq_get_acct(worker);
struct io_wq *wq = worker->wq;
bool exit_mask = false, last_timeout = false;
char buf[TASK_COMM_LEN];
worker->flags |= (IO_WORKER_F_UP | IO_WORKER_F_RUNNING);
snprintf(buf, sizeof(buf), "iou-wrk-%d", wq->task->pid);
set_task_comm(current, buf);
while (!test_bit(IO_WQ_BIT_EXIT, &wq->state)) {
long ret;
set_current_state(TASK_INTERRUPTIBLE);
/*
* If we have work to do, io_acct_run_queue() returns with
* the acct->lock held. If not, it will drop it.
*/
while (io_acct_run_queue(acct))
io_worker_handle_work(acct, worker);
raw_spin_lock(&wq->lock);
/*
* Last sleep timed out. Exit if we're not the last worker,
* or if someone modified our affinity.
*/
if (last_timeout && (exit_mask || acct->nr_workers > 1)) {
acct->nr_workers--;
raw_spin_unlock(&wq->lock);
__set_current_state(TASK_RUNNING);
break;
}
last_timeout = false;
__io_worker_idle(wq, worker);
raw_spin_unlock(&wq->lock);
if (io_run_task_work())
continue;
ret = schedule_timeout(WORKER_IDLE_TIMEOUT);
if (signal_pending(current)) {
struct ksignal ksig;
if (!get_signal(&ksig))
continue;
break;
}
if (!ret) {
last_timeout = true;
exit_mask = !cpumask_test_cpu(raw_smp_processor_id(),
wq->cpu_mask);
}
}
if (test_bit(IO_WQ_BIT_EXIT, &wq->state) && io_acct_run_queue(acct))
io_worker_handle_work(acct, worker);
io_worker_exit(worker);
return 0;
}
/*
* Called when a worker is scheduled in. Mark us as currently running.
*/
void io_wq_worker_running(struct task_struct *tsk)
{
struct io_worker *worker = tsk->worker_private;
if (!worker)
return;
if (!(worker->flags & IO_WORKER_F_UP))
return;
if (worker->flags & IO_WORKER_F_RUNNING)
return;
worker->flags |= IO_WORKER_F_RUNNING;
io_wq_inc_running(worker);
}
/*
* Called when worker is going to sleep. If there are no workers currently
* running and we have work pending, wake up a free one or create a new one.
*/
void io_wq_worker_sleeping(struct task_struct *tsk)
{
struct io_worker *worker = tsk->worker_private;
if (!worker)
return;
if (!(worker->flags & IO_WORKER_F_UP))
return;
if (!(worker->flags & IO_WORKER_F_RUNNING))
return;
worker->flags &= ~IO_WORKER_F_RUNNING;
io_wq_dec_running(worker);
}
static void io_init_new_worker(struct io_wq *wq, struct io_worker *worker,
struct task_struct *tsk)
{
tsk->worker_private = worker;
worker->task = tsk;
set_cpus_allowed_ptr(tsk, wq->cpu_mask);
raw_spin_lock(&wq->lock);
hlist_nulls_add_head_rcu(&worker->nulls_node, &wq->free_list);
list_add_tail_rcu(&worker->all_list, &wq->all_list);
worker->flags |= IO_WORKER_F_FREE;
raw_spin_unlock(&wq->lock);
wake_up_new_task(tsk);
}
static bool io_wq_work_match_all(struct io_wq_work *work, void *data)
{
return true;
}
static inline bool io_should_retry_thread(long err)
{
/*
* Prevent perpetual task_work retry, if the task (or its group) is
* exiting.
*/
if (fatal_signal_pending(current))
return false;
switch (err) {
case -EAGAIN:
case -ERESTARTSYS:
case -ERESTARTNOINTR:
case -ERESTARTNOHAND:
return true;
default:
return false;
}
}
static void create_worker_cont(struct callback_head *cb)
{
struct io_worker *worker;
struct task_struct *tsk;
struct io_wq *wq;
worker = container_of(cb, struct io_worker, create_work);
clear_bit_unlock(0, &worker->create_state);
wq = worker->wq;
tsk = create_io_thread(io_wq_worker, worker, NUMA_NO_NODE);
if (!IS_ERR(tsk)) {
io_init_new_worker(wq, worker, tsk);
io_worker_release(worker);
return;
} else if (!io_should_retry_thread(PTR_ERR(tsk))) {
struct io_wq_acct *acct = io_wq_get_acct(worker);
atomic_dec(&acct->nr_running);
raw_spin_lock(&wq->lock);
acct->nr_workers--;
if (!acct->nr_workers) {
struct io_cb_cancel_data match = {
.fn = io_wq_work_match_all,
.cancel_all = true,
};
raw_spin_unlock(&wq->lock);
while (io_acct_cancel_pending_work(wq, acct, &match))
;
} else {
raw_spin_unlock(&wq->lock);
}
io_worker_ref_put(wq);
kfree(worker);
return;
}
/* re-create attempts grab a new worker ref, drop the existing one */
io_worker_release(worker);
schedule_work(&worker->work);
}
static void io_workqueue_create(struct work_struct *work)
{
struct io_worker *worker = container_of(work, struct io_worker, work);
struct io_wq_acct *acct = io_wq_get_acct(worker);
if (!io_queue_worker_create(worker, acct, create_worker_cont))
kfree(worker);
}
static bool create_io_worker(struct io_wq *wq, int index)
{
struct io_wq_acct *acct = &wq->acct[index];
struct io_worker *worker;
struct task_struct *tsk;
__set_current_state(TASK_RUNNING);
worker = kzalloc(sizeof(*worker), GFP_KERNEL);
if (!worker) {
fail:
atomic_dec(&acct->nr_running);
raw_spin_lock(&wq->lock);
acct->nr_workers--;
raw_spin_unlock(&wq->lock);
io_worker_ref_put(wq);
return false;
}
refcount_set(&worker->ref, 1);
worker->wq = wq;
raw_spin_lock_init(&worker->lock);
init_completion(&worker->ref_done);
if (index == IO_WQ_ACCT_BOUND)
worker->flags |= IO_WORKER_F_BOUND;
tsk = create_io_thread(io_wq_worker, worker, NUMA_NO_NODE);
if (!IS_ERR(tsk)) {
io_init_new_worker(wq, worker, tsk);
} else if (!io_should_retry_thread(PTR_ERR(tsk))) {
kfree(worker);
goto fail;
} else {
INIT_WORK(&worker->work, io_workqueue_create);
schedule_work(&worker->work);
}
return true;
}
/*
* Iterate the passed in list and call the specific function for each
* worker that isn't exiting
*/
static bool io_wq_for_each_worker(struct io_wq *wq,
bool (*func)(struct io_worker *, void *),
void *data)
{
struct io_worker *worker;
bool ret = false;
list_for_each_entry_rcu(worker, &wq->all_list, all_list) {
if (io_worker_get(worker)) {
/* no task if node is/was offline */
if (worker->task)
ret = func(worker, data);
io_worker_release(worker);
if (ret)
break;
}
}
return ret;
}
static bool io_wq_worker_wake(struct io_worker *worker, void *data)
{
__set_notify_signal(worker->task);
wake_up_process(worker->task);
return false;
}
static void io_run_cancel(struct io_wq_work *work, struct io_wq *wq)
{
do {
work->flags |= IO_WQ_WORK_CANCEL;
wq->do_work(work);
work = wq->free_work(work);
} while (work);
}
static void io_wq_insert_work(struct io_wq *wq, struct io_wq_work *work)
{
struct io_wq_acct *acct = io_work_get_acct(wq, work);
unsigned int hash;
struct io_wq_work *tail;
if (!io_wq_is_hashed(work)) {
append:
wq_list_add_tail(&work->list, &acct->work_list);
return;
}
hash = io_get_work_hash(work);
tail = wq->hash_tail[hash];
wq->hash_tail[hash] = work;
if (!tail)
goto append;
wq_list_add_after(&work->list, &tail->list, &acct->work_list);
}
static bool io_wq_work_match_item(struct io_wq_work *work, void *data)
{
return work == data;
}
void io_wq_enqueue(struct io_wq *wq, struct io_wq_work *work)
{
struct io_wq_acct *acct = io_work_get_acct(wq, work);
struct io_cb_cancel_data match;
unsigned work_flags = work->flags;
bool do_create;
/*
* If io-wq is exiting for this task, or if the request has explicitly
* been marked as one that should not get executed, cancel it here.
*/
if (test_bit(IO_WQ_BIT_EXIT, &wq->state) ||
(work->flags & IO_WQ_WORK_CANCEL)) {
io_run_cancel(work, wq);
return;
}
raw_spin_lock(&acct->lock);
io_wq_insert_work(wq, work);
clear_bit(IO_ACCT_STALLED_BIT, &acct->flags);
raw_spin_unlock(&acct->lock);
rcu_read_lock();
do_create = !io_wq_activate_free_worker(wq, acct);
rcu_read_unlock();
if (do_create && ((work_flags & IO_WQ_WORK_CONCURRENT) ||
!atomic_read(&acct->nr_running))) {
bool did_create;
did_create = io_wq_create_worker(wq, acct);
if (likely(did_create))
return;
raw_spin_lock(&wq->lock);
if (acct->nr_workers) {
raw_spin_unlock(&wq->lock);
return;
}
raw_spin_unlock(&wq->lock);
/* fatal condition, failed to create the first worker */
match.fn = io_wq_work_match_item,
match.data = work,
match.cancel_all = false,
io_acct_cancel_pending_work(wq, acct, &match);
}
}
/*
* Work items that hash to the same value will not be done in parallel.
* Used to limit concurrent writes, generally hashed by inode.
*/
void io_wq_hash_work(struct io_wq_work *work, void *val)
{
unsigned int bit;
bit = hash_ptr(val, IO_WQ_HASH_ORDER);
work->flags |= (IO_WQ_WORK_HASHED | (bit << IO_WQ_HASH_SHIFT));
}
static bool __io_wq_worker_cancel(struct io_worker *worker,
struct io_cb_cancel_data *match,
struct io_wq_work *work)
{
if (work && match->fn(work, match->data)) {
work->flags |= IO_WQ_WORK_CANCEL;
__set_notify_signal(worker->task);
return true;
}
return false;
}
static bool io_wq_worker_cancel(struct io_worker *worker, void *data)
{
struct io_cb_cancel_data *match = data;
/*
* Hold the lock to avoid ->cur_work going out of scope, caller
* may dereference the passed in work.
*/
raw_spin_lock(&worker->lock);
if (__io_wq_worker_cancel(worker, match, worker->cur_work) ||
__io_wq_worker_cancel(worker, match, worker->next_work))
match->nr_running++;
raw_spin_unlock(&worker->lock);
return match->nr_running && !match->cancel_all;
}
static inline void io_wq_remove_pending(struct io_wq *wq,
struct io_wq_work *work,
struct io_wq_work_node *prev)
{
struct io_wq_acct *acct = io_work_get_acct(wq, work);
unsigned int hash = io_get_work_hash(work);
struct io_wq_work *prev_work = NULL;
if (io_wq_is_hashed(work) && work == wq->hash_tail[hash]) {
if (prev)
prev_work = container_of(prev, struct io_wq_work, list);
if (prev_work && io_get_work_hash(prev_work) == hash)
wq->hash_tail[hash] = prev_work;
else
wq->hash_tail[hash] = NULL;
}
wq_list_del(&acct->work_list, &work->list, prev);
}
static bool io_acct_cancel_pending_work(struct io_wq *wq,
struct io_wq_acct *acct,
struct io_cb_cancel_data *match)
{
struct io_wq_work_node *node, *prev;
struct io_wq_work *work;
raw_spin_lock(&acct->lock);
wq_list_for_each(node, prev, &acct->work_list) {
work = container_of(node, struct io_wq_work, list);
if (!match->fn(work, match->data))
continue;
io_wq_remove_pending(wq, work, prev);
raw_spin_unlock(&acct->lock);
io_run_cancel(work, wq);
match->nr_pending++;
/* not safe to continue after unlock */
return true;
}
raw_spin_unlock(&acct->lock);
return false;
}
static void io_wq_cancel_pending_work(struct io_wq *wq,
struct io_cb_cancel_data *match)
{
int i;
retry:
for (i = 0; i < IO_WQ_ACCT_NR; i++) {
struct io_wq_acct *acct = io_get_acct(wq, i == 0);
if (io_acct_cancel_pending_work(wq, acct, match)) {
if (match->cancel_all)
goto retry;
break;
}
}
}
static void io_wq_cancel_running_work(struct io_wq *wq,
struct io_cb_cancel_data *match)
{
rcu_read_lock();
io_wq_for_each_worker(wq, io_wq_worker_cancel, match);
rcu_read_unlock();
}
enum io_wq_cancel io_wq_cancel_cb(struct io_wq *wq, work_cancel_fn *cancel,
void *data, bool cancel_all)
{
struct io_cb_cancel_data match = {
.fn = cancel,
.data = data,
.cancel_all = cancel_all,
};
/*
* First check pending list, if we're lucky we can just remove it
* from there. CANCEL_OK means that the work is returned as-new,
* no completion will be posted for it.
*
* Then check if a free (going busy) or busy worker has the work
* currently running. If we find it there, we'll return CANCEL_RUNNING
* as an indication that we attempt to signal cancellation. The
* completion will run normally in this case.
*
* Do both of these while holding the wq->lock, to ensure that
* we'll find a work item regardless of state.
*/
io_wq_cancel_pending_work(wq, &match);
if (match.nr_pending && !match.cancel_all)
return IO_WQ_CANCEL_OK;
raw_spin_lock(&wq->lock);
io_wq_cancel_running_work(wq, &match);
raw_spin_unlock(&wq->lock);
if (match.nr_running && !match.cancel_all)
return IO_WQ_CANCEL_RUNNING;
if (match.nr_running)
return IO_WQ_CANCEL_RUNNING;
if (match.nr_pending)
return IO_WQ_CANCEL_OK;
return IO_WQ_CANCEL_NOTFOUND;
}
static int io_wq_hash_wake(struct wait_queue_entry *wait, unsigned mode,
int sync, void *key)
{
struct io_wq *wq = container_of(wait, struct io_wq, wait);
int i;
list_del_init(&wait->entry);
rcu_read_lock();
for (i = 0; i < IO_WQ_ACCT_NR; i++) {
struct io_wq_acct *acct = &wq->acct[i];
if (test_and_clear_bit(IO_ACCT_STALLED_BIT, &acct->flags))
io_wq_activate_free_worker(wq, acct);
}
rcu_read_unlock();
return 1;
}
struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data)
{
int ret, i;
struct io_wq *wq;
if (WARN_ON_ONCE(!data->free_work || !data->do_work))
return ERR_PTR(-EINVAL);
if (WARN_ON_ONCE(!bounded))
return ERR_PTR(-EINVAL);
wq = kzalloc(sizeof(struct io_wq), GFP_KERNEL);
if (!wq)
return ERR_PTR(-ENOMEM);
ret = cpuhp_state_add_instance_nocalls(io_wq_online, &wq->cpuhp_node);
if (ret)
goto err_wq;
refcount_inc(&data->hash->refs);
wq->hash = data->hash;
wq->free_work = data->free_work;
wq->do_work = data->do_work;
ret = -ENOMEM;
if (!alloc_cpumask_var(&wq->cpu_mask, GFP_KERNEL))
goto err;
cpumask_copy(wq->cpu_mask, cpu_possible_mask);
wq->acct[IO_WQ_ACCT_BOUND].max_workers = bounded;
wq->acct[IO_WQ_ACCT_UNBOUND].max_workers =
task_rlimit(current, RLIMIT_NPROC);
INIT_LIST_HEAD(&wq->wait.entry);
wq->wait.func = io_wq_hash_wake;
for (i = 0; i < IO_WQ_ACCT_NR; i++) {
struct io_wq_acct *acct = &wq->acct[i];
acct->index = i;
atomic_set(&acct->nr_running, 0);
INIT_WQ_LIST(&acct->work_list);
raw_spin_lock_init(&acct->lock);
}
raw_spin_lock_init(&wq->lock);
INIT_HLIST_NULLS_HEAD(&wq->free_list, 0);
INIT_LIST_HEAD(&wq->all_list);
wq->task = get_task_struct(data->task);
atomic_set(&wq->worker_refs, 1);
init_completion(&wq->worker_done);
return wq;
err:
io_wq_put_hash(data->hash);
cpuhp_state_remove_instance_nocalls(io_wq_online, &wq->cpuhp_node);
free_cpumask_var(wq->cpu_mask);
err_wq:
kfree(wq);
return ERR_PTR(ret);
}
static bool io_task_work_match(struct callback_head *cb, void *data)
{
struct io_worker *worker;
if (cb->func != create_worker_cb && cb->func != create_worker_cont)
return false;
worker = container_of(cb, struct io_worker, create_work);
return worker->wq == data;
}
void io_wq_exit_start(struct io_wq *wq)
{
set_bit(IO_WQ_BIT_EXIT, &wq->state);
}
static void io_wq_cancel_tw_create(struct io_wq *wq)
{
struct callback_head *cb;
while ((cb = task_work_cancel_match(wq->task, io_task_work_match, wq)) != NULL) {
struct io_worker *worker;
worker = container_of(cb, struct io_worker, create_work);
io_worker_cancel_cb(worker);
/*
* Only the worker continuation helper has worker allocated and
* hence needs freeing.
*/
if (cb->func == create_worker_cont)
kfree(worker);
}
}
static void io_wq_exit_workers(struct io_wq *wq)
{
if (!wq->task)
return;
io_wq_cancel_tw_create(wq);
rcu_read_lock();
io_wq_for_each_worker(wq, io_wq_worker_wake, NULL);
rcu_read_unlock();
io_worker_ref_put(wq);
wait_for_completion(&wq->worker_done);
spin_lock_irq(&wq->hash->wait.lock);
list_del_init(&wq->wait.entry);
spin_unlock_irq(&wq->hash->wait.lock);
put_task_struct(wq->task);
wq->task = NULL;
}
static void io_wq_destroy(struct io_wq *wq)
{
struct io_cb_cancel_data match = {
.fn = io_wq_work_match_all,
.cancel_all = true,
};
cpuhp_state_remove_instance_nocalls(io_wq_online, &wq->cpuhp_node);
io_wq_cancel_pending_work(wq, &match);
free_cpumask_var(wq->cpu_mask);
io_wq_put_hash(wq->hash);
kfree(wq);
}
void io_wq_put_and_exit(struct io_wq *wq)
{
WARN_ON_ONCE(!test_bit(IO_WQ_BIT_EXIT, &wq->state));
io_wq_exit_workers(wq);
io_wq_destroy(wq);
}
struct online_data {
unsigned int cpu;
bool online;
};
static bool io_wq_worker_affinity(struct io_worker *worker, void *data)
{
struct online_data *od = data;
if (od->online)
cpumask_set_cpu(od->cpu, worker->wq->cpu_mask);
else
cpumask_clear_cpu(od->cpu, worker->wq->cpu_mask);
return false;
}
static int __io_wq_cpu_online(struct io_wq *wq, unsigned int cpu, bool online)
{
struct online_data od = {
.cpu = cpu,
.online = online
};
rcu_read_lock();
io_wq_for_each_worker(wq, io_wq_worker_affinity, &od);
rcu_read_unlock();
return 0;
}
static int io_wq_cpu_online(unsigned int cpu, struct hlist_node *node)
{
struct io_wq *wq = hlist_entry_safe(node, struct io_wq, cpuhp_node);
return __io_wq_cpu_online(wq, cpu, true);
}
static int io_wq_cpu_offline(unsigned int cpu, struct hlist_node *node)
{
struct io_wq *wq = hlist_entry_safe(node, struct io_wq, cpuhp_node);
return __io_wq_cpu_online(wq, cpu, false);
}
int io_wq_cpu_affinity(struct io_uring_task *tctx, cpumask_var_t mask)
{
if (!tctx || !tctx->io_wq)
return -EINVAL;
rcu_read_lock();
if (mask)
cpumask_copy(tctx->io_wq->cpu_mask, mask);
else
cpumask_copy(tctx->io_wq->cpu_mask, cpu_possible_mask);
rcu_read_unlock();
return 0;
}
/*
* Set max number of unbounded workers, returns old value. If new_count is 0,
* then just return the old value.
*/
int io_wq_max_workers(struct io_wq *wq, int *new_count)
{
struct io_wq_acct *acct;
int prev[IO_WQ_ACCT_NR];
int i;
BUILD_BUG_ON((int) IO_WQ_ACCT_BOUND != (int) IO_WQ_BOUND);
BUILD_BUG_ON((int) IO_WQ_ACCT_UNBOUND != (int) IO_WQ_UNBOUND);
BUILD_BUG_ON((int) IO_WQ_ACCT_NR != 2);
for (i = 0; i < IO_WQ_ACCT_NR; i++) {
if (new_count[i] > task_rlimit(current, RLIMIT_NPROC))
new_count[i] = task_rlimit(current, RLIMIT_NPROC);
}
for (i = 0; i < IO_WQ_ACCT_NR; i++)
prev[i] = 0;
rcu_read_lock();
raw_spin_lock(&wq->lock);
for (i = 0; i < IO_WQ_ACCT_NR; i++) {
acct = &wq->acct[i];
prev[i] = max_t(int, acct->max_workers, prev[i]);
if (new_count[i])
acct->max_workers = new_count[i];
}
raw_spin_unlock(&wq->lock);
rcu_read_unlock();
for (i = 0; i < IO_WQ_ACCT_NR; i++)
new_count[i] = prev[i];
return 0;
}
static __init int io_wq_init(void)
{
int ret;
ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, "io-wq/online",
io_wq_cpu_online, io_wq_cpu_offline);
if (ret < 0)
return ret;
io_wq_online = ret;
return 0;
}
subsys_initcall(io_wq_init);
| linux-master | io_uring/io-wq.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/namei.h>
#include <linux/io_uring.h>
#include <uapi/linux/io_uring.h>
#include "../fs/internal.h"
#include "io_uring.h"
#include "fs.h"
struct io_rename {
struct file *file;
int old_dfd;
int new_dfd;
struct filename *oldpath;
struct filename *newpath;
int flags;
};
struct io_unlink {
struct file *file;
int dfd;
int flags;
struct filename *filename;
};
struct io_mkdir {
struct file *file;
int dfd;
umode_t mode;
struct filename *filename;
};
struct io_link {
struct file *file;
int old_dfd;
int new_dfd;
struct filename *oldpath;
struct filename *newpath;
int flags;
};
int io_renameat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_rename *ren = io_kiocb_to_cmd(req, struct io_rename);
const char __user *oldf, *newf;
if (sqe->buf_index || sqe->splice_fd_in)
return -EINVAL;
if (unlikely(req->flags & REQ_F_FIXED_FILE))
return -EBADF;
ren->old_dfd = READ_ONCE(sqe->fd);
oldf = u64_to_user_ptr(READ_ONCE(sqe->addr));
newf = u64_to_user_ptr(READ_ONCE(sqe->addr2));
ren->new_dfd = READ_ONCE(sqe->len);
ren->flags = READ_ONCE(sqe->rename_flags);
ren->oldpath = getname(oldf);
if (IS_ERR(ren->oldpath))
return PTR_ERR(ren->oldpath);
ren->newpath = getname(newf);
if (IS_ERR(ren->newpath)) {
putname(ren->oldpath);
return PTR_ERR(ren->newpath);
}
req->flags |= REQ_F_NEED_CLEANUP;
req->flags |= REQ_F_FORCE_ASYNC;
return 0;
}
int io_renameat(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_rename *ren = io_kiocb_to_cmd(req, struct io_rename);
int ret;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
ret = do_renameat2(ren->old_dfd, ren->oldpath, ren->new_dfd,
ren->newpath, ren->flags);
req->flags &= ~REQ_F_NEED_CLEANUP;
io_req_set_res(req, ret, 0);
return IOU_OK;
}
void io_renameat_cleanup(struct io_kiocb *req)
{
struct io_rename *ren = io_kiocb_to_cmd(req, struct io_rename);
putname(ren->oldpath);
putname(ren->newpath);
}
int io_unlinkat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_unlink *un = io_kiocb_to_cmd(req, struct io_unlink);
const char __user *fname;
if (sqe->off || sqe->len || sqe->buf_index || sqe->splice_fd_in)
return -EINVAL;
if (unlikely(req->flags & REQ_F_FIXED_FILE))
return -EBADF;
un->dfd = READ_ONCE(sqe->fd);
un->flags = READ_ONCE(sqe->unlink_flags);
if (un->flags & ~AT_REMOVEDIR)
return -EINVAL;
fname = u64_to_user_ptr(READ_ONCE(sqe->addr));
un->filename = getname(fname);
if (IS_ERR(un->filename))
return PTR_ERR(un->filename);
req->flags |= REQ_F_NEED_CLEANUP;
req->flags |= REQ_F_FORCE_ASYNC;
return 0;
}
int io_unlinkat(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_unlink *un = io_kiocb_to_cmd(req, struct io_unlink);
int ret;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
if (un->flags & AT_REMOVEDIR)
ret = do_rmdir(un->dfd, un->filename);
else
ret = do_unlinkat(un->dfd, un->filename);
req->flags &= ~REQ_F_NEED_CLEANUP;
io_req_set_res(req, ret, 0);
return IOU_OK;
}
void io_unlinkat_cleanup(struct io_kiocb *req)
{
struct io_unlink *ul = io_kiocb_to_cmd(req, struct io_unlink);
putname(ul->filename);
}
int io_mkdirat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_mkdir *mkd = io_kiocb_to_cmd(req, struct io_mkdir);
const char __user *fname;
if (sqe->off || sqe->rw_flags || sqe->buf_index || sqe->splice_fd_in)
return -EINVAL;
if (unlikely(req->flags & REQ_F_FIXED_FILE))
return -EBADF;
mkd->dfd = READ_ONCE(sqe->fd);
mkd->mode = READ_ONCE(sqe->len);
fname = u64_to_user_ptr(READ_ONCE(sqe->addr));
mkd->filename = getname(fname);
if (IS_ERR(mkd->filename))
return PTR_ERR(mkd->filename);
req->flags |= REQ_F_NEED_CLEANUP;
req->flags |= REQ_F_FORCE_ASYNC;
return 0;
}
int io_mkdirat(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_mkdir *mkd = io_kiocb_to_cmd(req, struct io_mkdir);
int ret;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
ret = do_mkdirat(mkd->dfd, mkd->filename, mkd->mode);
req->flags &= ~REQ_F_NEED_CLEANUP;
io_req_set_res(req, ret, 0);
return IOU_OK;
}
void io_mkdirat_cleanup(struct io_kiocb *req)
{
struct io_mkdir *md = io_kiocb_to_cmd(req, struct io_mkdir);
putname(md->filename);
}
int io_symlinkat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_link *sl = io_kiocb_to_cmd(req, struct io_link);
const char __user *oldpath, *newpath;
if (sqe->len || sqe->rw_flags || sqe->buf_index || sqe->splice_fd_in)
return -EINVAL;
if (unlikely(req->flags & REQ_F_FIXED_FILE))
return -EBADF;
sl->new_dfd = READ_ONCE(sqe->fd);
oldpath = u64_to_user_ptr(READ_ONCE(sqe->addr));
newpath = u64_to_user_ptr(READ_ONCE(sqe->addr2));
sl->oldpath = getname(oldpath);
if (IS_ERR(sl->oldpath))
return PTR_ERR(sl->oldpath);
sl->newpath = getname(newpath);
if (IS_ERR(sl->newpath)) {
putname(sl->oldpath);
return PTR_ERR(sl->newpath);
}
req->flags |= REQ_F_NEED_CLEANUP;
req->flags |= REQ_F_FORCE_ASYNC;
return 0;
}
int io_symlinkat(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_link *sl = io_kiocb_to_cmd(req, struct io_link);
int ret;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
ret = do_symlinkat(sl->oldpath, sl->new_dfd, sl->newpath);
req->flags &= ~REQ_F_NEED_CLEANUP;
io_req_set_res(req, ret, 0);
return IOU_OK;
}
int io_linkat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_link *lnk = io_kiocb_to_cmd(req, struct io_link);
const char __user *oldf, *newf;
if (sqe->rw_flags || sqe->buf_index || sqe->splice_fd_in)
return -EINVAL;
if (unlikely(req->flags & REQ_F_FIXED_FILE))
return -EBADF;
lnk->old_dfd = READ_ONCE(sqe->fd);
lnk->new_dfd = READ_ONCE(sqe->len);
oldf = u64_to_user_ptr(READ_ONCE(sqe->addr));
newf = u64_to_user_ptr(READ_ONCE(sqe->addr2));
lnk->flags = READ_ONCE(sqe->hardlink_flags);
lnk->oldpath = getname(oldf);
if (IS_ERR(lnk->oldpath))
return PTR_ERR(lnk->oldpath);
lnk->newpath = getname(newf);
if (IS_ERR(lnk->newpath)) {
putname(lnk->oldpath);
return PTR_ERR(lnk->newpath);
}
req->flags |= REQ_F_NEED_CLEANUP;
req->flags |= REQ_F_FORCE_ASYNC;
return 0;
}
int io_linkat(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_link *lnk = io_kiocb_to_cmd(req, struct io_link);
int ret;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
ret = do_linkat(lnk->old_dfd, lnk->oldpath, lnk->new_dfd,
lnk->newpath, lnk->flags);
req->flags &= ~REQ_F_NEED_CLEANUP;
io_req_set_res(req, ret, 0);
return IOU_OK;
}
void io_link_cleanup(struct io_kiocb *req)
{
struct io_link *sl = io_kiocb_to_cmd(req, struct io_link);
putname(sl->oldpath);
putname(sl->newpath);
}
| linux-master | io_uring/fs.c |
// SPDX-License-Identifier: GPL-2.0
/*
* io_uring opcode handling table
*/
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/io_uring.h>
#include "io_uring.h"
#include "opdef.h"
#include "refs.h"
#include "tctx.h"
#include "sqpoll.h"
#include "fdinfo.h"
#include "kbuf.h"
#include "rsrc.h"
#include "xattr.h"
#include "nop.h"
#include "fs.h"
#include "splice.h"
#include "sync.h"
#include "advise.h"
#include "openclose.h"
#include "uring_cmd.h"
#include "epoll.h"
#include "statx.h"
#include "net.h"
#include "msg_ring.h"
#include "timeout.h"
#include "poll.h"
#include "cancel.h"
#include "rw.h"
static int io_no_issue(struct io_kiocb *req, unsigned int issue_flags)
{
WARN_ON_ONCE(1);
return -ECANCELED;
}
static __maybe_unused int io_eopnotsupp_prep(struct io_kiocb *kiocb,
const struct io_uring_sqe *sqe)
{
return -EOPNOTSUPP;
}
const struct io_issue_def io_issue_defs[] = {
[IORING_OP_NOP] = {
.audit_skip = 1,
.iopoll = 1,
.prep = io_nop_prep,
.issue = io_nop,
},
[IORING_OP_READV] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollin = 1,
.buffer_select = 1,
.plug = 1,
.audit_skip = 1,
.ioprio = 1,
.iopoll = 1,
.iopoll_queue = 1,
.prep = io_prep_rw,
.issue = io_read,
},
[IORING_OP_WRITEV] = {
.needs_file = 1,
.hash_reg_file = 1,
.unbound_nonreg_file = 1,
.pollout = 1,
.plug = 1,
.audit_skip = 1,
.ioprio = 1,
.iopoll = 1,
.iopoll_queue = 1,
.prep = io_prep_rw,
.issue = io_write,
},
[IORING_OP_FSYNC] = {
.needs_file = 1,
.audit_skip = 1,
.prep = io_fsync_prep,
.issue = io_fsync,
},
[IORING_OP_READ_FIXED] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollin = 1,
.plug = 1,
.audit_skip = 1,
.ioprio = 1,
.iopoll = 1,
.iopoll_queue = 1,
.prep = io_prep_rw,
.issue = io_read,
},
[IORING_OP_WRITE_FIXED] = {
.needs_file = 1,
.hash_reg_file = 1,
.unbound_nonreg_file = 1,
.pollout = 1,
.plug = 1,
.audit_skip = 1,
.ioprio = 1,
.iopoll = 1,
.iopoll_queue = 1,
.prep = io_prep_rw,
.issue = io_write,
},
[IORING_OP_POLL_ADD] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.audit_skip = 1,
.prep = io_poll_add_prep,
.issue = io_poll_add,
},
[IORING_OP_POLL_REMOVE] = {
.audit_skip = 1,
.prep = io_poll_remove_prep,
.issue = io_poll_remove,
},
[IORING_OP_SYNC_FILE_RANGE] = {
.needs_file = 1,
.audit_skip = 1,
.prep = io_sfr_prep,
.issue = io_sync_file_range,
},
[IORING_OP_SENDMSG] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollout = 1,
.ioprio = 1,
.manual_alloc = 1,
#if defined(CONFIG_NET)
.prep = io_sendmsg_prep,
.issue = io_sendmsg,
#else
.prep = io_eopnotsupp_prep,
#endif
},
[IORING_OP_RECVMSG] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollin = 1,
.buffer_select = 1,
.ioprio = 1,
.manual_alloc = 1,
#if defined(CONFIG_NET)
.prep = io_recvmsg_prep,
.issue = io_recvmsg,
#else
.prep = io_eopnotsupp_prep,
#endif
},
[IORING_OP_TIMEOUT] = {
.audit_skip = 1,
.prep = io_timeout_prep,
.issue = io_timeout,
},
[IORING_OP_TIMEOUT_REMOVE] = {
/* used by timeout updates' prep() */
.audit_skip = 1,
.prep = io_timeout_remove_prep,
.issue = io_timeout_remove,
},
[IORING_OP_ACCEPT] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollin = 1,
.poll_exclusive = 1,
.ioprio = 1, /* used for flags */
#if defined(CONFIG_NET)
.prep = io_accept_prep,
.issue = io_accept,
#else
.prep = io_eopnotsupp_prep,
#endif
},
[IORING_OP_ASYNC_CANCEL] = {
.audit_skip = 1,
.prep = io_async_cancel_prep,
.issue = io_async_cancel,
},
[IORING_OP_LINK_TIMEOUT] = {
.audit_skip = 1,
.prep = io_link_timeout_prep,
.issue = io_no_issue,
},
[IORING_OP_CONNECT] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollout = 1,
#if defined(CONFIG_NET)
.prep = io_connect_prep,
.issue = io_connect,
#else
.prep = io_eopnotsupp_prep,
#endif
},
[IORING_OP_FALLOCATE] = {
.needs_file = 1,
.prep = io_fallocate_prep,
.issue = io_fallocate,
},
[IORING_OP_OPENAT] = {
.prep = io_openat_prep,
.issue = io_openat,
},
[IORING_OP_CLOSE] = {
.prep = io_close_prep,
.issue = io_close,
},
[IORING_OP_FILES_UPDATE] = {
.audit_skip = 1,
.iopoll = 1,
.prep = io_files_update_prep,
.issue = io_files_update,
},
[IORING_OP_STATX] = {
.audit_skip = 1,
.prep = io_statx_prep,
.issue = io_statx,
},
[IORING_OP_READ] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollin = 1,
.buffer_select = 1,
.plug = 1,
.audit_skip = 1,
.ioprio = 1,
.iopoll = 1,
.iopoll_queue = 1,
.prep = io_prep_rw,
.issue = io_read,
},
[IORING_OP_WRITE] = {
.needs_file = 1,
.hash_reg_file = 1,
.unbound_nonreg_file = 1,
.pollout = 1,
.plug = 1,
.audit_skip = 1,
.ioprio = 1,
.iopoll = 1,
.iopoll_queue = 1,
.prep = io_prep_rw,
.issue = io_write,
},
[IORING_OP_FADVISE] = {
.needs_file = 1,
.audit_skip = 1,
.prep = io_fadvise_prep,
.issue = io_fadvise,
},
[IORING_OP_MADVISE] = {
.audit_skip = 1,
.prep = io_madvise_prep,
.issue = io_madvise,
},
[IORING_OP_SEND] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollout = 1,
.audit_skip = 1,
.ioprio = 1,
.manual_alloc = 1,
#if defined(CONFIG_NET)
.prep = io_sendmsg_prep,
.issue = io_send,
#else
.prep = io_eopnotsupp_prep,
#endif
},
[IORING_OP_RECV] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollin = 1,
.buffer_select = 1,
.audit_skip = 1,
.ioprio = 1,
#if defined(CONFIG_NET)
.prep = io_recvmsg_prep,
.issue = io_recv,
#else
.prep = io_eopnotsupp_prep,
#endif
},
[IORING_OP_OPENAT2] = {
.prep = io_openat2_prep,
.issue = io_openat2,
},
[IORING_OP_EPOLL_CTL] = {
.unbound_nonreg_file = 1,
.audit_skip = 1,
#if defined(CONFIG_EPOLL)
.prep = io_epoll_ctl_prep,
.issue = io_epoll_ctl,
#else
.prep = io_eopnotsupp_prep,
#endif
},
[IORING_OP_SPLICE] = {
.needs_file = 1,
.hash_reg_file = 1,
.unbound_nonreg_file = 1,
.audit_skip = 1,
.prep = io_splice_prep,
.issue = io_splice,
},
[IORING_OP_PROVIDE_BUFFERS] = {
.audit_skip = 1,
.iopoll = 1,
.prep = io_provide_buffers_prep,
.issue = io_provide_buffers,
},
[IORING_OP_REMOVE_BUFFERS] = {
.audit_skip = 1,
.iopoll = 1,
.prep = io_remove_buffers_prep,
.issue = io_remove_buffers,
},
[IORING_OP_TEE] = {
.needs_file = 1,
.hash_reg_file = 1,
.unbound_nonreg_file = 1,
.audit_skip = 1,
.prep = io_tee_prep,
.issue = io_tee,
},
[IORING_OP_SHUTDOWN] = {
.needs_file = 1,
#if defined(CONFIG_NET)
.prep = io_shutdown_prep,
.issue = io_shutdown,
#else
.prep = io_eopnotsupp_prep,
#endif
},
[IORING_OP_RENAMEAT] = {
.prep = io_renameat_prep,
.issue = io_renameat,
},
[IORING_OP_UNLINKAT] = {
.prep = io_unlinkat_prep,
.issue = io_unlinkat,
},
[IORING_OP_MKDIRAT] = {
.prep = io_mkdirat_prep,
.issue = io_mkdirat,
},
[IORING_OP_SYMLINKAT] = {
.prep = io_symlinkat_prep,
.issue = io_symlinkat,
},
[IORING_OP_LINKAT] = {
.prep = io_linkat_prep,
.issue = io_linkat,
},
[IORING_OP_MSG_RING] = {
.needs_file = 1,
.iopoll = 1,
.prep = io_msg_ring_prep,
.issue = io_msg_ring,
},
[IORING_OP_FSETXATTR] = {
.needs_file = 1,
.prep = io_fsetxattr_prep,
.issue = io_fsetxattr,
},
[IORING_OP_SETXATTR] = {
.prep = io_setxattr_prep,
.issue = io_setxattr,
},
[IORING_OP_FGETXATTR] = {
.needs_file = 1,
.prep = io_fgetxattr_prep,
.issue = io_fgetxattr,
},
[IORING_OP_GETXATTR] = {
.prep = io_getxattr_prep,
.issue = io_getxattr,
},
[IORING_OP_SOCKET] = {
.audit_skip = 1,
#if defined(CONFIG_NET)
.prep = io_socket_prep,
.issue = io_socket,
#else
.prep = io_eopnotsupp_prep,
#endif
},
[IORING_OP_URING_CMD] = {
.needs_file = 1,
.plug = 1,
.iopoll = 1,
.iopoll_queue = 1,
.prep = io_uring_cmd_prep,
.issue = io_uring_cmd,
},
[IORING_OP_SEND_ZC] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollout = 1,
.audit_skip = 1,
.ioprio = 1,
.manual_alloc = 1,
#if defined(CONFIG_NET)
.prep = io_send_zc_prep,
.issue = io_send_zc,
#else
.prep = io_eopnotsupp_prep,
#endif
},
[IORING_OP_SENDMSG_ZC] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollout = 1,
.ioprio = 1,
.manual_alloc = 1,
#if defined(CONFIG_NET)
.prep = io_send_zc_prep,
.issue = io_sendmsg_zc,
#else
.prep = io_eopnotsupp_prep,
#endif
},
};
const struct io_cold_def io_cold_defs[] = {
[IORING_OP_NOP] = {
.name = "NOP",
},
[IORING_OP_READV] = {
.async_size = sizeof(struct io_async_rw),
.name = "READV",
.prep_async = io_readv_prep_async,
.cleanup = io_readv_writev_cleanup,
.fail = io_rw_fail,
},
[IORING_OP_WRITEV] = {
.async_size = sizeof(struct io_async_rw),
.name = "WRITEV",
.prep_async = io_writev_prep_async,
.cleanup = io_readv_writev_cleanup,
.fail = io_rw_fail,
},
[IORING_OP_FSYNC] = {
.name = "FSYNC",
},
[IORING_OP_READ_FIXED] = {
.async_size = sizeof(struct io_async_rw),
.name = "READ_FIXED",
.fail = io_rw_fail,
},
[IORING_OP_WRITE_FIXED] = {
.async_size = sizeof(struct io_async_rw),
.name = "WRITE_FIXED",
.fail = io_rw_fail,
},
[IORING_OP_POLL_ADD] = {
.name = "POLL_ADD",
},
[IORING_OP_POLL_REMOVE] = {
.name = "POLL_REMOVE",
},
[IORING_OP_SYNC_FILE_RANGE] = {
.name = "SYNC_FILE_RANGE",
},
[IORING_OP_SENDMSG] = {
.name = "SENDMSG",
#if defined(CONFIG_NET)
.async_size = sizeof(struct io_async_msghdr),
.prep_async = io_sendmsg_prep_async,
.cleanup = io_sendmsg_recvmsg_cleanup,
.fail = io_sendrecv_fail,
#endif
},
[IORING_OP_RECVMSG] = {
.name = "RECVMSG",
#if defined(CONFIG_NET)
.async_size = sizeof(struct io_async_msghdr),
.prep_async = io_recvmsg_prep_async,
.cleanup = io_sendmsg_recvmsg_cleanup,
.fail = io_sendrecv_fail,
#endif
},
[IORING_OP_TIMEOUT] = {
.async_size = sizeof(struct io_timeout_data),
.name = "TIMEOUT",
},
[IORING_OP_TIMEOUT_REMOVE] = {
.name = "TIMEOUT_REMOVE",
},
[IORING_OP_ACCEPT] = {
.name = "ACCEPT",
},
[IORING_OP_ASYNC_CANCEL] = {
.name = "ASYNC_CANCEL",
},
[IORING_OP_LINK_TIMEOUT] = {
.async_size = sizeof(struct io_timeout_data),
.name = "LINK_TIMEOUT",
},
[IORING_OP_CONNECT] = {
.name = "CONNECT",
#if defined(CONFIG_NET)
.async_size = sizeof(struct io_async_connect),
.prep_async = io_connect_prep_async,
#endif
},
[IORING_OP_FALLOCATE] = {
.name = "FALLOCATE",
},
[IORING_OP_OPENAT] = {
.name = "OPENAT",
.cleanup = io_open_cleanup,
},
[IORING_OP_CLOSE] = {
.name = "CLOSE",
},
[IORING_OP_FILES_UPDATE] = {
.name = "FILES_UPDATE",
},
[IORING_OP_STATX] = {
.name = "STATX",
.cleanup = io_statx_cleanup,
},
[IORING_OP_READ] = {
.async_size = sizeof(struct io_async_rw),
.name = "READ",
.fail = io_rw_fail,
},
[IORING_OP_WRITE] = {
.async_size = sizeof(struct io_async_rw),
.name = "WRITE",
.fail = io_rw_fail,
},
[IORING_OP_FADVISE] = {
.name = "FADVISE",
},
[IORING_OP_MADVISE] = {
.name = "MADVISE",
},
[IORING_OP_SEND] = {
.name = "SEND",
#if defined(CONFIG_NET)
.async_size = sizeof(struct io_async_msghdr),
.fail = io_sendrecv_fail,
.prep_async = io_send_prep_async,
#endif
},
[IORING_OP_RECV] = {
.name = "RECV",
#if defined(CONFIG_NET)
.fail = io_sendrecv_fail,
#endif
},
[IORING_OP_OPENAT2] = {
.name = "OPENAT2",
.cleanup = io_open_cleanup,
},
[IORING_OP_EPOLL_CTL] = {
.name = "EPOLL",
},
[IORING_OP_SPLICE] = {
.name = "SPLICE",
},
[IORING_OP_PROVIDE_BUFFERS] = {
.name = "PROVIDE_BUFFERS",
},
[IORING_OP_REMOVE_BUFFERS] = {
.name = "REMOVE_BUFFERS",
},
[IORING_OP_TEE] = {
.name = "TEE",
},
[IORING_OP_SHUTDOWN] = {
.name = "SHUTDOWN",
},
[IORING_OP_RENAMEAT] = {
.name = "RENAMEAT",
.cleanup = io_renameat_cleanup,
},
[IORING_OP_UNLINKAT] = {
.name = "UNLINKAT",
.cleanup = io_unlinkat_cleanup,
},
[IORING_OP_MKDIRAT] = {
.name = "MKDIRAT",
.cleanup = io_mkdirat_cleanup,
},
[IORING_OP_SYMLINKAT] = {
.name = "SYMLINKAT",
.cleanup = io_link_cleanup,
},
[IORING_OP_LINKAT] = {
.name = "LINKAT",
.cleanup = io_link_cleanup,
},
[IORING_OP_MSG_RING] = {
.name = "MSG_RING",
.cleanup = io_msg_ring_cleanup,
},
[IORING_OP_FSETXATTR] = {
.name = "FSETXATTR",
.cleanup = io_xattr_cleanup,
},
[IORING_OP_SETXATTR] = {
.name = "SETXATTR",
.cleanup = io_xattr_cleanup,
},
[IORING_OP_FGETXATTR] = {
.name = "FGETXATTR",
.cleanup = io_xattr_cleanup,
},
[IORING_OP_GETXATTR] = {
.name = "GETXATTR",
.cleanup = io_xattr_cleanup,
},
[IORING_OP_SOCKET] = {
.name = "SOCKET",
},
[IORING_OP_URING_CMD] = {
.name = "URING_CMD",
.async_size = 2 * sizeof(struct io_uring_sqe),
.prep_async = io_uring_cmd_prep_async,
},
[IORING_OP_SEND_ZC] = {
.name = "SEND_ZC",
#if defined(CONFIG_NET)
.async_size = sizeof(struct io_async_msghdr),
.prep_async = io_send_prep_async,
.cleanup = io_send_zc_cleanup,
.fail = io_sendrecv_fail,
#endif
},
[IORING_OP_SENDMSG_ZC] = {
.name = "SENDMSG_ZC",
#if defined(CONFIG_NET)
.async_size = sizeof(struct io_async_msghdr),
.prep_async = io_sendmsg_prep_async,
.cleanup = io_send_zc_cleanup,
.fail = io_sendrecv_fail,
#endif
},
};
const char *io_uring_get_opcode(u8 opcode)
{
if (opcode < IORING_OP_LAST)
return io_cold_defs[opcode].name;
return "INVALID";
}
void __init io_uring_optable_init(void)
{
int i;
BUILD_BUG_ON(ARRAY_SIZE(io_cold_defs) != IORING_OP_LAST);
BUILD_BUG_ON(ARRAY_SIZE(io_issue_defs) != IORING_OP_LAST);
for (i = 0; i < ARRAY_SIZE(io_issue_defs); i++) {
BUG_ON(!io_issue_defs[i].prep);
if (io_issue_defs[i].prep != io_eopnotsupp_prep)
BUG_ON(!io_issue_defs[i].issue);
WARN_ON_ONCE(!io_cold_defs[i].name);
}
}
| linux-master | io_uring/opdef.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/file.h>
#include <linux/slab.h>
#include <linux/nospec.h>
#include <linux/io_uring.h>
#include <uapi/linux/io_uring.h>
#include "io_uring.h"
#include "rsrc.h"
#include "filetable.h"
#include "msg_ring.h"
/* All valid masks for MSG_RING */
#define IORING_MSG_RING_MASK (IORING_MSG_RING_CQE_SKIP | \
IORING_MSG_RING_FLAGS_PASS)
struct io_msg {
struct file *file;
struct file *src_file;
struct callback_head tw;
u64 user_data;
u32 len;
u32 cmd;
u32 src_fd;
union {
u32 dst_fd;
u32 cqe_flags;
};
u32 flags;
};
static void io_double_unlock_ctx(struct io_ring_ctx *octx)
{
mutex_unlock(&octx->uring_lock);
}
static int io_double_lock_ctx(struct io_ring_ctx *octx,
unsigned int issue_flags)
{
/*
* To ensure proper ordering between the two ctxs, we can only
* attempt a trylock on the target. If that fails and we already have
* the source ctx lock, punt to io-wq.
*/
if (!(issue_flags & IO_URING_F_UNLOCKED)) {
if (!mutex_trylock(&octx->uring_lock))
return -EAGAIN;
return 0;
}
mutex_lock(&octx->uring_lock);
return 0;
}
void io_msg_ring_cleanup(struct io_kiocb *req)
{
struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
if (WARN_ON_ONCE(!msg->src_file))
return;
fput(msg->src_file);
msg->src_file = NULL;
}
static inline bool io_msg_need_remote(struct io_ring_ctx *target_ctx)
{
if (!target_ctx->task_complete)
return false;
return current != target_ctx->submitter_task;
}
static int io_msg_exec_remote(struct io_kiocb *req, task_work_func_t func)
{
struct io_ring_ctx *ctx = req->file->private_data;
struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
struct task_struct *task = READ_ONCE(ctx->submitter_task);
if (unlikely(!task))
return -EOWNERDEAD;
init_task_work(&msg->tw, func);
if (task_work_add(ctx->submitter_task, &msg->tw, TWA_SIGNAL))
return -EOWNERDEAD;
return IOU_ISSUE_SKIP_COMPLETE;
}
static void io_msg_tw_complete(struct callback_head *head)
{
struct io_msg *msg = container_of(head, struct io_msg, tw);
struct io_kiocb *req = cmd_to_io_kiocb(msg);
struct io_ring_ctx *target_ctx = req->file->private_data;
int ret = 0;
if (current->flags & PF_EXITING) {
ret = -EOWNERDEAD;
} else {
u32 flags = 0;
if (msg->flags & IORING_MSG_RING_FLAGS_PASS)
flags = msg->cqe_flags;
/*
* If the target ring is using IOPOLL mode, then we need to be
* holding the uring_lock for posting completions. Other ring
* types rely on the regular completion locking, which is
* handled while posting.
*/
if (target_ctx->flags & IORING_SETUP_IOPOLL)
mutex_lock(&target_ctx->uring_lock);
if (!io_post_aux_cqe(target_ctx, msg->user_data, msg->len, flags))
ret = -EOVERFLOW;
if (target_ctx->flags & IORING_SETUP_IOPOLL)
mutex_unlock(&target_ctx->uring_lock);
}
if (ret < 0)
req_set_fail(req);
io_req_queue_tw_complete(req, ret);
}
static int io_msg_ring_data(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_ring_ctx *target_ctx = req->file->private_data;
struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
u32 flags = 0;
int ret;
if (msg->src_fd || msg->flags & ~IORING_MSG_RING_FLAGS_PASS)
return -EINVAL;
if (!(msg->flags & IORING_MSG_RING_FLAGS_PASS) && msg->dst_fd)
return -EINVAL;
if (target_ctx->flags & IORING_SETUP_R_DISABLED)
return -EBADFD;
if (io_msg_need_remote(target_ctx))
return io_msg_exec_remote(req, io_msg_tw_complete);
if (msg->flags & IORING_MSG_RING_FLAGS_PASS)
flags = msg->cqe_flags;
ret = -EOVERFLOW;
if (target_ctx->flags & IORING_SETUP_IOPOLL) {
if (unlikely(io_double_lock_ctx(target_ctx, issue_flags)))
return -EAGAIN;
if (io_post_aux_cqe(target_ctx, msg->user_data, msg->len, flags))
ret = 0;
io_double_unlock_ctx(target_ctx);
} else {
if (io_post_aux_cqe(target_ctx, msg->user_data, msg->len, flags))
ret = 0;
}
return ret;
}
static struct file *io_msg_grab_file(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
struct io_ring_ctx *ctx = req->ctx;
struct file *file = NULL;
int idx = msg->src_fd;
io_ring_submit_lock(ctx, issue_flags);
if (likely(idx < ctx->nr_user_files)) {
idx = array_index_nospec(idx, ctx->nr_user_files);
file = io_file_from_index(&ctx->file_table, idx);
if (file)
get_file(file);
}
io_ring_submit_unlock(ctx, issue_flags);
return file;
}
static int io_msg_install_complete(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_ring_ctx *target_ctx = req->file->private_data;
struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
struct file *src_file = msg->src_file;
int ret;
if (unlikely(io_double_lock_ctx(target_ctx, issue_flags)))
return -EAGAIN;
ret = __io_fixed_fd_install(target_ctx, src_file, msg->dst_fd);
if (ret < 0)
goto out_unlock;
msg->src_file = NULL;
req->flags &= ~REQ_F_NEED_CLEANUP;
if (msg->flags & IORING_MSG_RING_CQE_SKIP)
goto out_unlock;
/*
* If this fails, the target still received the file descriptor but
* wasn't notified of the fact. This means that if this request
* completes with -EOVERFLOW, then the sender must ensure that a
* later IORING_OP_MSG_RING delivers the message.
*/
if (!io_post_aux_cqe(target_ctx, msg->user_data, ret, 0))
ret = -EOVERFLOW;
out_unlock:
io_double_unlock_ctx(target_ctx);
return ret;
}
static void io_msg_tw_fd_complete(struct callback_head *head)
{
struct io_msg *msg = container_of(head, struct io_msg, tw);
struct io_kiocb *req = cmd_to_io_kiocb(msg);
int ret = -EOWNERDEAD;
if (!(current->flags & PF_EXITING))
ret = io_msg_install_complete(req, IO_URING_F_UNLOCKED);
if (ret < 0)
req_set_fail(req);
io_req_queue_tw_complete(req, ret);
}
static int io_msg_send_fd(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_ring_ctx *target_ctx = req->file->private_data;
struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
struct io_ring_ctx *ctx = req->ctx;
struct file *src_file = msg->src_file;
if (msg->len)
return -EINVAL;
if (target_ctx == ctx)
return -EINVAL;
if (target_ctx->flags & IORING_SETUP_R_DISABLED)
return -EBADFD;
if (!src_file) {
src_file = io_msg_grab_file(req, issue_flags);
if (!src_file)
return -EBADF;
msg->src_file = src_file;
req->flags |= REQ_F_NEED_CLEANUP;
}
if (io_msg_need_remote(target_ctx))
return io_msg_exec_remote(req, io_msg_tw_fd_complete);
return io_msg_install_complete(req, issue_flags);
}
int io_msg_ring_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
if (unlikely(sqe->buf_index || sqe->personality))
return -EINVAL;
msg->src_file = NULL;
msg->user_data = READ_ONCE(sqe->off);
msg->len = READ_ONCE(sqe->len);
msg->cmd = READ_ONCE(sqe->addr);
msg->src_fd = READ_ONCE(sqe->addr3);
msg->dst_fd = READ_ONCE(sqe->file_index);
msg->flags = READ_ONCE(sqe->msg_ring_flags);
if (msg->flags & ~IORING_MSG_RING_MASK)
return -EINVAL;
return 0;
}
int io_msg_ring(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
int ret;
ret = -EBADFD;
if (!io_is_uring_fops(req->file))
goto done;
switch (msg->cmd) {
case IORING_MSG_DATA:
ret = io_msg_ring_data(req, issue_flags);
break;
case IORING_MSG_SEND_FD:
ret = io_msg_send_fd(req, issue_flags);
break;
default:
ret = -EINVAL;
break;
}
done:
if (ret < 0) {
if (ret == -EAGAIN || ret == IOU_ISSUE_SKIP_COMPLETE)
return ret;
req_set_fail(req);
}
io_req_set_res(req, ret, 0);
return IOU_OK;
}
| linux-master | io_uring/msg_ring.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/file.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/nospec.h>
#include <linux/io_uring.h>
#include <uapi/linux/io_uring.h>
#include "io_uring.h"
#include "tctx.h"
static struct io_wq *io_init_wq_offload(struct io_ring_ctx *ctx,
struct task_struct *task)
{
struct io_wq_hash *hash;
struct io_wq_data data;
unsigned int concurrency;
mutex_lock(&ctx->uring_lock);
hash = ctx->hash_map;
if (!hash) {
hash = kzalloc(sizeof(*hash), GFP_KERNEL);
if (!hash) {
mutex_unlock(&ctx->uring_lock);
return ERR_PTR(-ENOMEM);
}
refcount_set(&hash->refs, 1);
init_waitqueue_head(&hash->wait);
ctx->hash_map = hash;
}
mutex_unlock(&ctx->uring_lock);
data.hash = hash;
data.task = task;
data.free_work = io_wq_free_work;
data.do_work = io_wq_submit_work;
/* Do QD, or 4 * CPUS, whatever is smallest */
concurrency = min(ctx->sq_entries, 4 * num_online_cpus());
return io_wq_create(concurrency, &data);
}
void __io_uring_free(struct task_struct *tsk)
{
struct io_uring_task *tctx = tsk->io_uring;
WARN_ON_ONCE(!xa_empty(&tctx->xa));
WARN_ON_ONCE(tctx->io_wq);
WARN_ON_ONCE(tctx->cached_refs);
percpu_counter_destroy(&tctx->inflight);
kfree(tctx);
tsk->io_uring = NULL;
}
__cold int io_uring_alloc_task_context(struct task_struct *task,
struct io_ring_ctx *ctx)
{
struct io_uring_task *tctx;
int ret;
tctx = kzalloc(sizeof(*tctx), GFP_KERNEL);
if (unlikely(!tctx))
return -ENOMEM;
ret = percpu_counter_init(&tctx->inflight, 0, GFP_KERNEL);
if (unlikely(ret)) {
kfree(tctx);
return ret;
}
tctx->io_wq = io_init_wq_offload(ctx, task);
if (IS_ERR(tctx->io_wq)) {
ret = PTR_ERR(tctx->io_wq);
percpu_counter_destroy(&tctx->inflight);
kfree(tctx);
return ret;
}
xa_init(&tctx->xa);
init_waitqueue_head(&tctx->wait);
atomic_set(&tctx->in_cancel, 0);
atomic_set(&tctx->inflight_tracked, 0);
task->io_uring = tctx;
init_llist_head(&tctx->task_list);
init_task_work(&tctx->task_work, tctx_task_work);
return 0;
}
int __io_uring_add_tctx_node(struct io_ring_ctx *ctx)
{
struct io_uring_task *tctx = current->io_uring;
struct io_tctx_node *node;
int ret;
if (unlikely(!tctx)) {
ret = io_uring_alloc_task_context(current, ctx);
if (unlikely(ret))
return ret;
tctx = current->io_uring;
if (ctx->iowq_limits_set) {
unsigned int limits[2] = { ctx->iowq_limits[0],
ctx->iowq_limits[1], };
ret = io_wq_max_workers(tctx->io_wq, limits);
if (ret)
return ret;
}
}
if (!xa_load(&tctx->xa, (unsigned long)ctx)) {
node = kmalloc(sizeof(*node), GFP_KERNEL);
if (!node)
return -ENOMEM;
node->ctx = ctx;
node->task = current;
ret = xa_err(xa_store(&tctx->xa, (unsigned long)ctx,
node, GFP_KERNEL));
if (ret) {
kfree(node);
return ret;
}
mutex_lock(&ctx->uring_lock);
list_add(&node->ctx_node, &ctx->tctx_list);
mutex_unlock(&ctx->uring_lock);
}
return 0;
}
int __io_uring_add_tctx_node_from_submit(struct io_ring_ctx *ctx)
{
int ret;
if (ctx->flags & IORING_SETUP_SINGLE_ISSUER
&& ctx->submitter_task != current)
return -EEXIST;
ret = __io_uring_add_tctx_node(ctx);
if (ret)
return ret;
current->io_uring->last = ctx;
return 0;
}
/*
* Remove this io_uring_file -> task mapping.
*/
__cold void io_uring_del_tctx_node(unsigned long index)
{
struct io_uring_task *tctx = current->io_uring;
struct io_tctx_node *node;
if (!tctx)
return;
node = xa_erase(&tctx->xa, index);
if (!node)
return;
WARN_ON_ONCE(current != node->task);
WARN_ON_ONCE(list_empty(&node->ctx_node));
mutex_lock(&node->ctx->uring_lock);
list_del(&node->ctx_node);
mutex_unlock(&node->ctx->uring_lock);
if (tctx->last == node->ctx)
tctx->last = NULL;
kfree(node);
}
__cold void io_uring_clean_tctx(struct io_uring_task *tctx)
{
struct io_wq *wq = tctx->io_wq;
struct io_tctx_node *node;
unsigned long index;
xa_for_each(&tctx->xa, index, node) {
io_uring_del_tctx_node(index);
cond_resched();
}
if (wq) {
/*
* Must be after io_uring_del_tctx_node() (removes nodes under
* uring_lock) to avoid race with io_uring_try_cancel_iowq().
*/
io_wq_put_and_exit(wq);
tctx->io_wq = NULL;
}
}
void io_uring_unreg_ringfd(void)
{
struct io_uring_task *tctx = current->io_uring;
int i;
for (i = 0; i < IO_RINGFD_REG_MAX; i++) {
if (tctx->registered_rings[i]) {
fput(tctx->registered_rings[i]);
tctx->registered_rings[i] = NULL;
}
}
}
int io_ring_add_registered_file(struct io_uring_task *tctx, struct file *file,
int start, int end)
{
int offset;
for (offset = start; offset < end; offset++) {
offset = array_index_nospec(offset, IO_RINGFD_REG_MAX);
if (tctx->registered_rings[offset])
continue;
tctx->registered_rings[offset] = file;
return offset;
}
return -EBUSY;
}
static int io_ring_add_registered_fd(struct io_uring_task *tctx, int fd,
int start, int end)
{
struct file *file;
int offset;
file = fget(fd);
if (!file) {
return -EBADF;
} else if (!io_is_uring_fops(file)) {
fput(file);
return -EOPNOTSUPP;
}
offset = io_ring_add_registered_file(tctx, file, start, end);
if (offset < 0)
fput(file);
return offset;
}
/*
* Register a ring fd to avoid fdget/fdput for each io_uring_enter()
* invocation. User passes in an array of struct io_uring_rsrc_update
* with ->data set to the ring_fd, and ->offset given for the desired
* index. If no index is desired, application may set ->offset == -1U
* and we'll find an available index. Returns number of entries
* successfully processed, or < 0 on error if none were processed.
*/
int io_ringfd_register(struct io_ring_ctx *ctx, void __user *__arg,
unsigned nr_args)
{
struct io_uring_rsrc_update __user *arg = __arg;
struct io_uring_rsrc_update reg;
struct io_uring_task *tctx;
int ret, i;
if (!nr_args || nr_args > IO_RINGFD_REG_MAX)
return -EINVAL;
mutex_unlock(&ctx->uring_lock);
ret = __io_uring_add_tctx_node(ctx);
mutex_lock(&ctx->uring_lock);
if (ret)
return ret;
tctx = current->io_uring;
for (i = 0; i < nr_args; i++) {
int start, end;
if (copy_from_user(®, &arg[i], sizeof(reg))) {
ret = -EFAULT;
break;
}
if (reg.resv) {
ret = -EINVAL;
break;
}
if (reg.offset == -1U) {
start = 0;
end = IO_RINGFD_REG_MAX;
} else {
if (reg.offset >= IO_RINGFD_REG_MAX) {
ret = -EINVAL;
break;
}
start = reg.offset;
end = start + 1;
}
ret = io_ring_add_registered_fd(tctx, reg.data, start, end);
if (ret < 0)
break;
reg.offset = ret;
if (copy_to_user(&arg[i], ®, sizeof(reg))) {
fput(tctx->registered_rings[reg.offset]);
tctx->registered_rings[reg.offset] = NULL;
ret = -EFAULT;
break;
}
}
return i ? i : ret;
}
int io_ringfd_unregister(struct io_ring_ctx *ctx, void __user *__arg,
unsigned nr_args)
{
struct io_uring_rsrc_update __user *arg = __arg;
struct io_uring_task *tctx = current->io_uring;
struct io_uring_rsrc_update reg;
int ret = 0, i;
if (!nr_args || nr_args > IO_RINGFD_REG_MAX)
return -EINVAL;
if (!tctx)
return 0;
for (i = 0; i < nr_args; i++) {
if (copy_from_user(®, &arg[i], sizeof(reg))) {
ret = -EFAULT;
break;
}
if (reg.resv || reg.data || reg.offset >= IO_RINGFD_REG_MAX) {
ret = -EINVAL;
break;
}
reg.offset = array_index_nospec(reg.offset, IO_RINGFD_REG_MAX);
if (tctx->registered_rings[reg.offset]) {
fput(tctx->registered_rings[reg.offset]);
tctx->registered_rings[reg.offset] = NULL;
}
}
return i ? i : ret;
}
| linux-master | io_uring/tctx.c |
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