text: /*
   * Copyright (C) 2011-2017, Red Hat Inc, Arnaldo Carvalho de Melo <acme@redhat.com>
   *
   * Parts came from evlist.c builtin-{top,stat,record}.c, see those files for further
   * copyright notes.
   *
   * Released under the GPL v2. (and only v2, not any later version)
   */
  
  #include <sys/mman.h>
  #include <inttypes.h>
  #include <asm/bug.h>
  #ifdef HAVE_LIBNUMA_SUPPORT
  #include <numaif.h>
  #endif
  #include "debug.h"
  #include "event.h"
  #include "mmap.h"
  #include "util.h" /* page_size */
  
  size_t perf_mmap__mmap_len(struct perf_mmap *map)
  {
  	return map->mask + 1 + page_size;
  }
  
  /* When check_messup is true, 'end' must points to a good entry */
  static union perf_event *perf_mmap__read(struct perf_mmap *map,
  					 u64 *startp, u64 end)
  {
  	unsigned char *data = map->base + page_size;
  	union perf_event *event = NULL;
  	int diff = end - *startp;
  
  	if (diff >= (int)sizeof(event->header)) {
  		size_t size;
  
  		event = (union perf_event *)&data[*startp & map->mask];
  		size = event->header.size;
  
  		if (size < sizeof(event->header) || diff < (int)size)
  			return NULL;
  
  		/*
  		 * Event straddles the mmap boundary -- header should always
  		 * be inside due to u64 alignment of output.
  		 */
  		if ((*startp & map->mask) + size != ((*startp + size) & map->mask)) {
  			unsigned int offset = *startp;
  			unsigned int len = min(sizeof(*event), size), cpy;
  			void *dst = map->event_copy;
  
  			do {
  				cpy = min(map->mask + 1 - (offset & map->mask), len);
  				memcpy(dst, &data[offset & map->mask], cpy);
  				offset += cpy;
  				dst += cpy;
  				len -= cpy;
  			} while (len);
  
  			event = (union perf_event *)map->event_copy;
  		}
  
  		*startp += size;
  	}
  
  	return event;
  }
  
  /*
   * Read event from ring buffer one by one.
   * Return one event for each call.
   *
   * Usage:
   * perf_mmap__read_init()
   * while(event = perf_mmap__read_event()) {
   *	//process the event
   *	perf_mmap__consume()
   * }
   * perf_mmap__read_done()
   */
  union perf_event *perf_mmap__read_event(struct perf_mmap *map)
  {
  	union perf_event *event;
  
  	/*
  	 * Check if event was unmapped due to a POLLHUP/POLLERR.
  	 */
  	if (!refcount_read(&map->refcnt))
  		return NULL;
  
  	/* non-overwirte doesn't pause the ringbuffer */
  	if (!map->overwrite)
  		map->end = perf_mmap__read_head(map);
  
  	event = perf_mmap__read(map, &map->start, map->end);
  
  	if (!map->overwrite)
  		map->prev = map->start;
  
  	return event;
  }
  
  static bool perf_mmap__empty(struct perf_mmap *map)
  {
  	return perf_mmap__read_head(map) == map->prev && !map->auxtrace_mmap.base;
  }
  
  void perf_mmap__get(struct perf_mmap *map)
  {
  	refcount_inc(&map->refcnt);
  }
  
  void perf_mmap__put(struct perf_mmap *map)
  {
  	BUG_ON(map->base && refcount_read(&map->refcnt) == 0);
  
  	if (refcount_dec_and_test(&map->refcnt))
  		perf_mmap__munmap(map);
  }
  
  void perf_mmap__consume(struct perf_mmap *map)
  {
  	if (!map->overwrite) {
  		u64 old = map->prev;
  
  		perf_mmap__write_tail(map, old);
  	}
  
  	if (refcount_read(&map->refcnt) == 1 && perf_mmap__empty(map))
  		perf_mmap__put(map);
  }
  
  int __weak auxtrace_mmap__mmap(struct auxtrace_mmap *mm __maybe_unused,
  			       struct auxtrace_mmap_params *mp __maybe_unused,
  			       void *userpg __maybe_unused,
  			       int fd __maybe_unused)
  {
  	return 0;
  }
  
  void __weak auxtrace_mmap__munmap(struct auxtrace_mmap *mm __maybe_unused)
  {
  }
  
  void __weak auxtrace_mmap_params__init(struct auxtrace_mmap_params *mp __maybe_unused,
  				       off_t auxtrace_offset __maybe_unused,
  				       unsigned int auxtrace_pages __maybe_unused,
  				       bool auxtrace_overwrite __maybe_unused)
  {
  }
  
  void __weak auxtrace_mmap_params__set_idx(struct auxtrace_mmap_params *mp __maybe_unused,
  					  struct perf_evlist *evlist __maybe_unused,
  					  int idx __maybe_unused,
  					  bool per_cpu __maybe_unused)
  {
  }
  
  #ifdef HAVE_AIO_SUPPORT
  
  #ifdef HAVE_LIBNUMA_SUPPORT
  static int perf_mmap__aio_alloc(struct perf_mmap *map, int idx)
  {
  	map->aio.data[idx] = mmap(NULL, perf_mmap__mmap_len(map), PROT_READ|PROT_WRITE,
  				  MAP_PRIVATE|MAP_ANONYMOUS, 0, 0);
  	if (map->aio.data[idx] == MAP_FAILED) {
  		map->aio.data[idx] = NULL;
  		return -1;
  	}
  
  	return 0;
  }
  
  static void perf_mmap__aio_free(struct perf_mmap *map, int idx)
  {
  	if (map->aio.data[idx]) {
  		munmap(map->aio.data[idx], perf_mmap__mmap_len(map));
  		map->aio.data[idx] = NULL;
  	}
  }
  
  static int perf_mmap__aio_bind(struct perf_mmap *map, int idx, int cpu, int affinity)
  {
  	void *data;
  	size_t mmap_len;
  	unsigned long node_mask;
  
  	if (affinity != PERF_AFFINITY_SYS && cpu__max_node() > 1) {
  		data = map->aio.data[idx];
  		mmap_len = perf_mmap__mmap_len(map);
  		node_mask = 1UL << cpu__get_node(cpu);
  		if (mbind(data, mmap_len, MPOL_BIND, &node_mask, 1, 0)) {
  			pr_err("Failed to bind [%p-%p] AIO buffer to node %d: error %m\n",
  				data, data + mmap_len, cpu__get_node(cpu));
  			return -1;
  		}
  	}
  
  	return 0;
  }
  #else
  static int perf_mmap__aio_alloc(struct perf_mmap *map, int idx)
  {
  	map->aio.data[idx] = malloc(perf_mmap__mmap_len(map));
  	if (map->aio.data[idx] == NULL)
  		return -1;
  
  	return 0;
  }
  
  static void perf_mmap__aio_free(struct perf_mmap *map, int idx)
  {
  	zfree(&(map->aio.data[idx]));
  }
  
  static int perf_mmap__aio_bind(struct perf_mmap *map __maybe_unused, int idx __maybe_unused,
  		int cpu __maybe_unused, int affinity __maybe_unused)
  {
  	return 0;
  }
  #endif
  
  static int perf_mmap__aio_mmap(struct perf_mmap *map, struct mmap_params *mp)
  {
  	int delta_max, i, prio, ret;
  
  	map->aio.nr_cblocks = mp->nr_cblocks;
  	if (map->aio.nr_cblocks) {
  		map->aio.aiocb = calloc(map->aio.nr_cblocks, sizeof(struct aiocb *));
  		if (!map->aio.aiocb) {
  			pr_debug2("failed to allocate aiocb for data buffer, error %m\n");
  			return -1;
  		}
  		map->aio.cblocks = calloc(map->aio.nr_cblocks, sizeof(struct aiocb));
  		if (!map->aio.cblocks) {
  			pr_debug2("failed to allocate cblocks for data buffer, error %m\n");
  			return -1;
  		}
  		map->aio.data = calloc(map->aio.nr_cblocks, sizeof(void *));
  		if (!map->aio.data) {
  			pr_debug2("failed to allocate data buffer, error %m\n");
  			return -1;
  		}
  		delta_max = sysconf(_SC_AIO_PRIO_DELTA_MAX);
  		for (i = 0; i < map->aio.nr_cblocks; ++i) {
  			ret = perf_mmap__aio_alloc(map, i);
  			if (ret == -1) {
  				pr_debug2("failed to allocate data buffer area, error %m");
  				return -1;
  			}
  			ret = perf_mmap__aio_bind(map, i, map->cpu, mp->affinity);
  			if (ret == -1)
  				return -1;
  			/*
  			 * Use cblock.aio_fildes value different from -1
  			 * to denote started aio write operation on the
  			 * cblock so it requires explicit record__aio_sync()
  			 * call prior the cblock may be reused again.
  			 */
  			map->aio.cblocks[i].aio_fildes = -1;
  			/*
  			 * Allocate cblocks with priority delta to have
  			 * faster aio write system calls because queued requests
  			 * are kept in separate per-prio queues and adding
  			 * a new request will iterate thru shorter per-prio
  			 * list. Blocks with numbers higher than
  			 *  _SC_AIO_PRIO_DELTA_MAX go with priority 0.
  			 */
  			prio = delta_max - i;
  			map->aio.cblocks[i].aio_reqprio = prio >= 0 ? prio : 0;
  		}
  	}
  
  	return 0;
  }
  
  static void perf_mmap__aio_munmap(struct perf_mmap *map)
  {
  	int i;
  
  	for (i = 0; i < map->aio.nr_cblocks; ++i)
  		perf_mmap__aio_free(map, i);
  	if (map->aio.data)
  		zfree(&map->aio.data);
  	zfree(&map->aio.cblocks);
  	zfree(&map->aio.aiocb);
  }
  
  int perf_mmap__aio_push(struct perf_mmap *md, void *to, int idx,
  			int push(void *to, struct aiocb *cblock, void *buf, size_t size, off_t off),
  			off_t *off)
  {
  	u64 head = perf_mmap__read_head(md);
  	unsigned char *data = md->base + page_size;
  	unsigned long size, size0 = 0;
  	void *buf;
  	int rc = 0;
  
  	rc = perf_mmap__read_init(md);
  	if (rc < 0)
  		return (rc == -EAGAIN) ? 0 : -1;
  
  	/*
  	 * md->base data is copied into md->data[idx] buffer to
  	 * release space in the kernel buffer as fast as possible,
  	 * thru perf_mmap__consume() below.
  	 *
  	 * That lets the kernel to proceed with storing more
  	 * profiling data into the kernel buffer earlier than other
  	 * per-cpu kernel buffers are handled.
  	 *
  	 * Coping can be done in two steps in case the chunk of
  	 * profiling data crosses the upper bound of the kernel buffer.
  	 * In this case we first move part of data from md->start
  	 * till the upper bound and then the reminder from the
  	 * beginning of the kernel buffer till the end of
  	 * the data chunk.
  	 */
  
  	size = md->end - md->start;
  
  	if ((md->start & md->mask) + size != (md->end & md->mask)) {
  		buf = &data[md->start & md->mask];
  		size = md->mask + 1 - (md->start & md->mask);
  		md->start += size;
  		memcpy(md->aio.data[idx], buf, size);
  		size0 = size;
  	}
  
  	buf = &data[md->start & md->mask];
  	size = md->end - md->start;
  	md->start += size;
  	memcpy(md->aio.data[idx] + size0, buf, size);
  
  	/*
  	 * Increment md->refcount to guard md->data[idx] buffer
  	 * from premature deallocation because md object can be
  	 * released earlier than aio write request started
  	 * on mmap->data[idx] is complete.
  	 *
  	 * perf_mmap__put() is done at record__aio_complete()
  	 * after started request completion.
  	 */
  	perf_mmap__get(md);
  
  	md->prev = head;
  	perf_mmap__consume(md);
  
  	rc = push(to, &md->aio.cblocks[idx], md->aio.data[idx], size0 + size, *off);
  	if (!rc) {
  		*off += size0 + size;
  	} else {
  		/*
  		 * Decrement md->refcount back if aio write
  		 * operation failed to start.
  		 */
  		perf_mmap__put(md);
  	}
  
  	return rc;
  }
  #else
  static int perf_mmap__aio_mmap(struct perf_mmap *map __maybe_unused,
  			       struct mmap_params *mp __maybe_unused)
  {
  	return 0;
  }
  
  static void perf_mmap__aio_munmap(struct perf_mmap *map __maybe_unused)
  {
  }
  #endif
  
  void perf_mmap__munmap(struct perf_mmap *map)
  {
  	perf_mmap__aio_munmap(map);
  	if (map->base != NULL) {
  		munmap(map->base, perf_mmap__mmap_len(map));
  		map->base = NULL;
  		map->fd = -1;
  		refcount_set(&map->refcnt, 0);
  	}
  	auxtrace_mmap__munmap(&map->auxtrace_mmap);
  }
  
  static void build_node_mask(int node, cpu_set_t *mask)
  {
  	int c, cpu, nr_cpus;
  	const struct cpu_map *cpu_map = NULL;
  
  	cpu_map = cpu_map__online();
  	if (!cpu_map)
  		return;
  
  	nr_cpus = cpu_map__nr(cpu_map);
  	for (c = 0; c < nr_cpus; c++) {
  		cpu = cpu_map->map[c]; /* map c index to online cpu index */
  		if (cpu__get_node(cpu) == node)
  			CPU_SET(cpu, mask);
  	}
  }
  
  static void perf_mmap__setup_affinity_mask(struct perf_mmap *map, struct mmap_params *mp)
  {
  	CPU_ZERO(&map->affinity_mask);
  	if (mp->affinity == PERF_AFFINITY_NODE && cpu__max_node() > 1)
  		build_node_mask(cpu__get_node(map->cpu), &map->affinity_mask);
  	else if (mp->affinity == PERF_AFFINITY_CPU)
  		CPU_SET(map->cpu, &map->affinity_mask);
  }
  
  int perf_mmap__mmap(struct perf_mmap *map, struct mmap_params *mp, int fd, int cpu)
  {
  	/*
  	 * The last one will be done at perf_mmap__consume(), so that we
  	 * make sure we don't prevent tools from consuming every last event in
  	 * the ring buffer.
  	 *
  	 * I.e. we can get the POLLHUP meaning that the fd doesn't exist
  	 * anymore, but the last events for it are still in the ring buffer,
  	 * waiting to be consumed.
  	 *
  	 * Tools can chose to ignore this at their own discretion, but the
  	 * evlist layer can't just drop it when filtering events in
  	 * perf_evlist__filter_pollfd().
  	 */
  	refcount_set(&map->refcnt, 2);
  	map->prev = 0;
  	map->mask = mp->mask;
  	map->base = mmap(NULL, perf_mmap__mmap_len(map), mp->prot,
  			 MAP_SHARED, fd, 0);
  	if (map->base == MAP_FAILED) {
  		pr_debug2("failed to mmap perf event ring buffer, error %d\n",
  			  errno);
  		map->base = NULL;
  		return -1;
  	}
  	map->fd = fd;
  	map->cpu = cpu;
  
  	perf_mmap__setup_affinity_mask(map, mp);
  
  	if (auxtrace_mmap__mmap(&map->auxtrace_mmap,
  				&mp->auxtrace_mp, map->base, fd))
  		return -1;
  
  	return perf_mmap__aio_mmap(map, mp);
  }
  
  static int overwrite_rb_find_range(void *buf, int mask, u64 *start, u64 *end)
  {
  	struct perf_event_header *pheader;
  	u64 evt_head = *start;
  	int size = mask + 1;
  
  	pr_debug2("%s: buf=%p, start=%"PRIx64"\n", __func__, buf, *start);
  	pheader = (struct perf_event_header *)(buf + (*start & mask));
  	while (true) {
  		if (evt_head - *start >= (unsigned int)size) {
  			pr_debug("Finished reading overwrite ring buffer: rewind\n");
  			if (evt_head - *start > (unsigned int)size)
  				evt_head -= pheader->size;
  			*end = evt_head;
  			return 0;
  		}
  
  		pheader = (struct perf_event_header *)(buf + (evt_head & mask));
  
  		if (pheader->size == 0) {
  			pr_debug("Finished reading overwrite ring buffer: get start\n");
  			*end = evt_head;
  			return 0;
  		}
  
  		evt_head += pheader->size;
  		pr_debug3("move evt_head: %"PRIx64"\n", evt_head);
  	}
  	WARN_ONCE(1, "Shouldn't get here\n");
  	return -1;
  }
  
  /*
   * Report the start and end of the available data in ringbuffer
   */
  static int __perf_mmap__read_init(struct perf_mmap *md)
  {
  	u64 head = perf_mmap__read_head(md);
  	u64 old = md->prev;
  	unsigned char *data = md->base + page_size;
  	unsigned long size;
  
  	md->start = md->overwrite ? head : old;
  	md->end = md->overwrite ? old : head;
  
  	if (md->start == md->end)
  		return -EAGAIN;
  
  	size = md->end - md->start;
  	if (size > (unsigned long)(md->mask) + 1) {
  		if (!md->overwrite) {
  			WARN_ONCE(1, "failed to keep up with mmap data. (warn only once)\n");
  
  			md->prev = head;
  			perf_mmap__consume(md);
  			return -EAGAIN;
  		}
  
  		/*
  		 * Backward ring buffer is full. We still have a chance to read
  		 * most of data from it.
  		 */
  		if (overwrite_rb_find_range(data, md->mask, &md->start, &md->end))
  			return -EINVAL;
  	}
  
  	return 0;
  }
  
  int perf_mmap__read_init(struct perf_mmap *map)
  {
  	/*
  	 * Check if event was unmapped due to a POLLHUP/POLLERR.
  	 */
  	if (!refcount_read(&map->refcnt))
  		return -ENOENT;
  
  	return __perf_mmap__read_init(map);
  }
  
  int perf_mmap__push(struct perf_mmap *md, void *to,
  		    int push(struct perf_mmap *map, void *to, void *buf, size_t size))
  {
  	u64 head = perf_mmap__read_head(md);
  	unsigned char *data = md->base + page_size;
  	unsigned long size;
  	void *buf;
  	int rc = 0;
  
  	rc = perf_mmap__read_init(md);
  	if (rc < 0)
  		return (rc == -EAGAIN) ? 0 : -1;
  
  	size = md->end - md->start;
  
  	if ((md->start & md->mask) + size != (md->end & md->mask)) {
  		buf = &data[md->start & md->mask];
  		size = md->mask + 1 - (md->start & md->mask);
  		md->start += size;
  
  		if (push(md, to, buf, size) < 0) {
  			rc = -1;
  			goto out;
  		}
  	}
  
  	buf = &data[md->start & md->mask];
  	size = md->end - md->start;
  	md->start += size;
  
  	if (push(md, to, buf, size) < 0) {
  		rc = -1;
  		goto out;
  	}
  
  	md->prev = head;
  	perf_mmap__consume(md);
  out:
  	return rc;
  }
  
  /*
   * Mandatory for overwrite mode
   * The direction of overwrite mode is backward.
   * The last perf_mmap__read() will set tail to map->prev.
   * Need to correct the map->prev to head which is the end of next read.
   */
  void perf_mmap__read_done(struct perf_mmap *map)
  {
  	/*
  	 * Check if event was unmapped due to a POLLHUP/POLLERR.
  	 */
  	if (!refcount_read(&map->refcnt))
  		return;
  
  	map->prev = perf_mmap__read_head(map);
  }
  