text: // SPDX-License-Identifier: GPL-2.0
  #include "symbol.h"
  #include <errno.h>
  #include <inttypes.h>
  #include <limits.h>
  #include <stdlib.h>
  #include <string.h>
  #include <stdio.h>
  #include <unistd.h>
  #include <uapi/linux/mman.h> /* To get things like MAP_HUGETLB even on older libc headers */
  #include "map.h"
  #include "thread.h"
  #include "vdso.h"
  #include "build-id.h"
  #include "util.h"
  #include "debug.h"
  #include "machine.h"
  #include <linux/string.h>
  #include "srcline.h"
  #include "namespaces.h"
  #include "unwind.h"
  
  static void __maps__insert(struct maps *maps, struct map *map);
  
  static inline int is_anon_memory(const char *filename, u32 flags)
  {
  	return flags & MAP_HUGETLB ||
  	       !strcmp(filename, "//anon") ||
  	       !strncmp(filename, "/dev/zero", sizeof("/dev/zero") - 1) ||
  	       !strncmp(filename, "/anon_hugepage", sizeof("/anon_hugepage") - 1);
  }
  
  static inline int is_no_dso_memory(const char *filename)
  {
  	return !strncmp(filename, "[stack", 6) ||
  	       !strncmp(filename, "/SYSV",5)   ||
  	       !strcmp(filename, "[heap]");
  }
  
  static inline int is_android_lib(const char *filename)
  {
  	return !strncmp(filename, "/data/app-lib", 13) ||
  	       !strncmp(filename, "/system/lib", 11);
  }
  
  static inline bool replace_android_lib(const char *filename, char *newfilename)
  {
  	const char *libname;
  	char *app_abi;
  	size_t app_abi_length, new_length;
  	size_t lib_length = 0;
  
  	libname  = strrchr(filename, '/');
  	if (libname)
  		lib_length = strlen(libname);
  
  	app_abi = getenv("APP_ABI");
  	if (!app_abi)
  		return false;
  
  	app_abi_length = strlen(app_abi);
  
  	if (!strncmp(filename, "/data/app-lib", 13)) {
  		char *apk_path;
  
  		if (!app_abi_length)
  			return false;
  
  		new_length = 7 + app_abi_length + lib_length;
  
  		apk_path = getenv("APK_PATH");
  		if (apk_path) {
  			new_length += strlen(apk_path) + 1;
  			if (new_length > PATH_MAX)
  				return false;
  			snprintf(newfilename, new_length,
  				 "%s/libs/%s/%s", apk_path, app_abi, libname);
  		} else {
  			if (new_length > PATH_MAX)
  				return false;
  			snprintf(newfilename, new_length,
  				 "libs/%s/%s", app_abi, libname);
  		}
  		return true;
  	}
  
  	if (!strncmp(filename, "/system/lib/", 11)) {
  		char *ndk, *app;
  		const char *arch;
  		size_t ndk_length;
  		size_t app_length;
  
  		ndk = getenv("NDK_ROOT");
  		app = getenv("APP_PLATFORM");
  
  		if (!(ndk && app))
  			return false;
  
  		ndk_length = strlen(ndk);
  		app_length = strlen(app);
  
  		if (!(ndk_length && app_length && app_abi_length))
  			return false;
  
  		arch = !strncmp(app_abi, "arm", 3) ? "arm" :
  		       !strncmp(app_abi, "mips", 4) ? "mips" :
  		       !strncmp(app_abi, "x86", 3) ? "x86" : NULL;
  
  		if (!arch)
  			return false;
  
  		new_length = 27 + ndk_length +
  			     app_length + lib_length
  			   + strlen(arch);
  
  		if (new_length > PATH_MAX)
  			return false;
  		snprintf(newfilename, new_length,
  			"%s/platforms/%s/arch-%s/usr/lib/%s",
  			ndk, app, arch, libname);
  
  		return true;
  	}
  	return false;
  }
  
  void map__init(struct map *map, u64 start, u64 end, u64 pgoff, struct dso *dso)
  {
  	map->start    = start;
  	map->end      = end;
  	map->pgoff    = pgoff;
  	map->reloc    = 0;
  	map->dso      = dso__get(dso);
  	map->map_ip   = map__map_ip;
  	map->unmap_ip = map__unmap_ip;
  	RB_CLEAR_NODE(&map->rb_node);
  	map->groups   = NULL;
  	map->erange_warned = false;
  	refcount_set(&map->refcnt, 1);
  }
  
  struct map *map__new(struct machine *machine, u64 start, u64 len,
  		     u64 pgoff, u32 d_maj, u32 d_min, u64 ino,
  		     u64 ino_gen, u32 prot, u32 flags, char *filename,
  		     struct thread *thread)
  {
  	struct map *map = malloc(sizeof(*map));
  	struct nsinfo *nsi = NULL;
  	struct nsinfo *nnsi;
  
  	if (map != NULL) {
  		char newfilename[PATH_MAX];
  		struct dso *dso;
  		int anon, no_dso, vdso, android;
  
  		android = is_android_lib(filename);
  		anon = is_anon_memory(filename, flags);
  		vdso = is_vdso_map(filename);
  		no_dso = is_no_dso_memory(filename);
  
  		map->maj = d_maj;
  		map->min = d_min;
  		map->ino = ino;
  		map->ino_generation = ino_gen;
  		map->prot = prot;
  		map->flags = flags;
  		nsi = nsinfo__get(thread->nsinfo);
  
  		if ((anon || no_dso) && nsi && (prot & PROT_EXEC)) {
  			snprintf(newfilename, sizeof(newfilename),
  				 "/tmp/perf-%d.map", nsi->pid);
  			filename = newfilename;
  		}
  
  		if (android) {
  			if (replace_android_lib(filename, newfilename))
  				filename = newfilename;
  		}
  
  		if (vdso) {
  			/* The vdso maps are always on the host and not the
  			 * container.  Ensure that we don't use setns to look
  			 * them up.
  			 */
  			nnsi = nsinfo__copy(nsi);
  			if (nnsi) {
  				nsinfo__put(nsi);
  				nnsi->need_setns = false;
  				nsi = nnsi;
  			}
  			pgoff = 0;
  			dso = machine__findnew_vdso(machine, thread);
  		} else
  			dso = machine__findnew_dso(machine, filename);
  
  		if (dso == NULL)
  			goto out_delete;
  
  		map__init(map, start, start + len, pgoff, dso);
  
  		if (anon || no_dso) {
  			map->map_ip = map->unmap_ip = identity__map_ip;
  
  			/*
  			 * Set memory without DSO as loaded. All map__find_*
  			 * functions still return NULL, and we avoid the
  			 * unnecessary map__load warning.
  			 */
  			if (!(prot & PROT_EXEC))
  				dso__set_loaded(dso);
  		}
  		dso->nsinfo = nsi;
  		dso__put(dso);
  	}
  	return map;
  out_delete:
  	nsinfo__put(nsi);
  	free(map);
  	return NULL;
  }
  
  /*
   * Constructor variant for modules (where we know from /proc/modules where
   * they are loaded) and for vmlinux, where only after we load all the
   * symbols we'll know where it starts and ends.
   */
  struct map *map__new2(u64 start, struct dso *dso)
  {
  	struct map *map = calloc(1, (sizeof(*map) +
  				     (dso->kernel ? sizeof(struct kmap) : 0)));
  	if (map != NULL) {
  		/*
  		 * ->end will be filled after we load all the symbols
  		 */
  		map__init(map, start, 0, 0, dso);
  	}
  
  	return map;
  }
  
  /*
   * Use this and __map__is_kmodule() for map instances that are in
   * machine->kmaps, and thus have map->groups->machine all properly set, to
   * disambiguate between the kernel and modules.
   *
   * When the need arises, introduce map__is_{kernel,kmodule)() that
   * checks (map->groups != NULL && map->groups->machine != NULL &&
   * map->dso->kernel) before calling __map__is_{kernel,kmodule}())
   */
  bool __map__is_kernel(const struct map *map)
  {
  	return machine__kernel_map(map->groups->machine) == map;
  }
  
  bool __map__is_extra_kernel_map(const struct map *map)
  {
  	struct kmap *kmap = __map__kmap((struct map *)map);
  
  	return kmap && kmap->name[0];
  }
  
  bool map__has_symbols(const struct map *map)
  {
  	return dso__has_symbols(map->dso);
  }
  
  static void map__exit(struct map *map)
  {
  	BUG_ON(!RB_EMPTY_NODE(&map->rb_node));
  	dso__zput(map->dso);
  }
  
  void map__delete(struct map *map)
  {
  	map__exit(map);
  	free(map);
  }
  
  void map__put(struct map *map)
  {
  	if (map && refcount_dec_and_test(&map->refcnt))
  		map__delete(map);
  }
  
  void map__fixup_start(struct map *map)
  {
  	struct rb_root *symbols = &map->dso->symbols;
  	struct rb_node *nd = rb_first(symbols);
  	if (nd != NULL) {
  		struct symbol *sym = rb_entry(nd, struct symbol, rb_node);
  		map->start = sym->start;
  	}
  }
  
  void map__fixup_end(struct map *map)
  {
  	struct rb_root *symbols = &map->dso->symbols;
  	struct rb_node *nd = rb_last(symbols);
  	if (nd != NULL) {
  		struct symbol *sym = rb_entry(nd, struct symbol, rb_node);
  		map->end = sym->end;
  	}
  }
  
  #define DSO__DELETED "(deleted)"
  
  int map__load(struct map *map)
  {
  	const char *name = map->dso->long_name;
  	int nr;
  
  	if (dso__loaded(map->dso))
  		return 0;
  
  	nr = dso__load(map->dso, map);
  	if (nr < 0) {
  		if (map->dso->has_build_id) {
  			char sbuild_id[SBUILD_ID_SIZE];
  
  			build_id__sprintf(map->dso->build_id,
  					  sizeof(map->dso->build_id),
  					  sbuild_id);
  			pr_debug("%s with build id %s not found", name, sbuild_id);
  		} else
  			pr_debug("Failed to open %s", name);
  
  		pr_debug(", continuing without symbols\n");
  		return -1;
  	} else if (nr == 0) {
  #ifdef HAVE_LIBELF_SUPPORT
  		const size_t len = strlen(name);
  		const size_t real_len = len - sizeof(DSO__DELETED);
  
  		if (len > sizeof(DSO__DELETED) &&
  		    strcmp(name + real_len + 1, DSO__DELETED) == 0) {
  			pr_debug("%.*s was updated (is prelink enabled?). "
  				"Restart the long running apps that use it!\n",
  				   (int)real_len, name);
  		} else {
  			pr_debug("no symbols found in %s, maybe install a debug package?\n", name);
  		}
  #endif
  		return -1;
  	}
  
  	return 0;
  }
  
  struct symbol *map__find_symbol(struct map *map, u64 addr)
  {
  	if (map__load(map) < 0)
  		return NULL;
  
  	return dso__find_symbol(map->dso, addr);
  }
  
  struct symbol *map__find_symbol_by_name(struct map *map, const char *name)
  {
  	if (map__load(map) < 0)
  		return NULL;
  
  	if (!dso__sorted_by_name(map->dso))
  		dso__sort_by_name(map->dso);
  
  	return dso__find_symbol_by_name(map->dso, name);
  }
  
  struct map *map__clone(struct map *from)
  {
  	struct map *map = memdup(from, sizeof(*map));
  
  	if (map != NULL) {
  		refcount_set(&map->refcnt, 1);
  		RB_CLEAR_NODE(&map->rb_node);
  		dso__get(map->dso);
  		map->groups = NULL;
  	}
  
  	return map;
  }
  
  size_t map__fprintf(struct map *map, FILE *fp)
  {
  	return fprintf(fp, " %" PRIx64 "-%" PRIx64 " %" PRIx64 " %s\n",
  		       map->start, map->end, map->pgoff, map->dso->name);
  }
  
  size_t map__fprintf_dsoname(struct map *map, FILE *fp)
  {
  	const char *dsoname = "[unknown]";
  
  	if (map && map->dso) {
  		if (symbol_conf.show_kernel_path && map->dso->long_name)
  			dsoname = map->dso->long_name;
  		else
  			dsoname = map->dso->name;
  	}
  
  	return fprintf(fp, "%s", dsoname);
  }
  
  char *map__srcline(struct map *map, u64 addr, struct symbol *sym)
  {
  	if (map == NULL)
  		return SRCLINE_UNKNOWN;
  	return get_srcline(map->dso, map__rip_2objdump(map, addr), sym, true, true, addr);
  }
  
  int map__fprintf_srcline(struct map *map, u64 addr, const char *prefix,
  			 FILE *fp)
  {
  	int ret = 0;
  
  	if (map && map->dso) {
  		char *srcline = map__srcline(map, addr, NULL);
  		if (srcline != SRCLINE_UNKNOWN)
  			ret = fprintf(fp, "%s%s", prefix, srcline);
  		free_srcline(srcline);
  	}
  	return ret;
  }
  
  /**
   * map__rip_2objdump - convert symbol start address to objdump address.
   * @map: memory map
   * @rip: symbol start address
   *
   * objdump wants/reports absolute IPs for ET_EXEC, and RIPs for ET_DYN.
   * map->dso->adjust_symbols==1 for ET_EXEC-like cases except ET_REL which is
   * relative to section start.
   *
   * Return: Address suitable for passing to "objdump --start-address="
   */
  u64 map__rip_2objdump(struct map *map, u64 rip)
  {
  	struct kmap *kmap = __map__kmap(map);
  
  	/*
  	 * vmlinux does not have program headers for PTI entry trampolines and
  	 * kcore may not either. However the trampoline object code is on the
  	 * main kernel map, so just use that instead.
  	 */
  	if (kmap && is_entry_trampoline(kmap->name) && kmap->kmaps && kmap->kmaps->machine) {
  		struct map *kernel_map = machine__kernel_map(kmap->kmaps->machine);
  
  		if (kernel_map)
  			map = kernel_map;
  	}
  
  	if (!map->dso->adjust_symbols)
  		return rip;
  
  	if (map->dso->rel)
  		return rip - map->pgoff;
  
  	/*
  	 * kernel modules also have DSO_TYPE_USER in dso->kernel,
  	 * but all kernel modules are ET_REL, so won't get here.
  	 */
  	if (map->dso->kernel == DSO_TYPE_USER)
  		return rip + map->dso->text_offset;
  
  	return map->unmap_ip(map, rip) - map->reloc;
  }
  
  /**
   * map__objdump_2mem - convert objdump address to a memory address.
   * @map: memory map
   * @ip: objdump address
   *
   * Closely related to map__rip_2objdump(), this function takes an address from
   * objdump and converts it to a memory address.  Note this assumes that @map
   * contains the address.  To be sure the result is valid, check it forwards
   * e.g. map__rip_2objdump(map->map_ip(map, map__objdump_2mem(map, ip))) == ip
   *
   * Return: Memory address.
   */
  u64 map__objdump_2mem(struct map *map, u64 ip)
  {
  	if (!map->dso->adjust_symbols)
  		return map->unmap_ip(map, ip);
  
  	if (map->dso->rel)
  		return map->unmap_ip(map, ip + map->pgoff);
  
  	/*
  	 * kernel modules also have DSO_TYPE_USER in dso->kernel,
  	 * but all kernel modules are ET_REL, so won't get here.
  	 */
  	if (map->dso->kernel == DSO_TYPE_USER)
  		return map->unmap_ip(map, ip - map->dso->text_offset);
  
  	return ip + map->reloc;
  }
  
  static void maps__init(struct maps *maps)
  {
  	maps->entries = RB_ROOT;
  	init_rwsem(&maps->lock);
  }
  
  void map_groups__init(struct map_groups *mg, struct machine *machine)
  {
  	maps__init(&mg->maps);
  	mg->machine = machine;
  	refcount_set(&mg->refcnt, 1);
  }
  
  static void __maps__purge(struct maps *maps)
  {
  	struct rb_root *root = &maps->entries;
  	struct rb_node *next = rb_first(root);
  
  	while (next) {
  		struct map *pos = rb_entry(next, struct map, rb_node);
  
  		next = rb_next(&pos->rb_node);
  		rb_erase_init(&pos->rb_node, root);
  		map__put(pos);
  	}
  }
  
  static void maps__exit(struct maps *maps)
  {
  	down_write(&maps->lock);
  	__maps__purge(maps);
  	up_write(&maps->lock);
  }
  
  void map_groups__exit(struct map_groups *mg)
  {
  	maps__exit(&mg->maps);
  }
  
  bool map_groups__empty(struct map_groups *mg)
  {
  	return !maps__first(&mg->maps);
  }
  
  struct map_groups *map_groups__new(struct machine *machine)
  {
  	struct map_groups *mg = malloc(sizeof(*mg));
  
  	if (mg != NULL)
  		map_groups__init(mg, machine);
  
  	return mg;
  }
  
  void map_groups__delete(struct map_groups *mg)
  {
  	map_groups__exit(mg);
  	free(mg);
  }
  
  void map_groups__put(struct map_groups *mg)
  {
  	if (mg && refcount_dec_and_test(&mg->refcnt))
  		map_groups__delete(mg);
  }
  
  struct symbol *map_groups__find_symbol(struct map_groups *mg,
  				       u64 addr, struct map **mapp)
  {
  	struct map *map = map_groups__find(mg, addr);
  
  	/* Ensure map is loaded before using map->map_ip */
  	if (map != NULL && map__load(map) >= 0) {
  		if (mapp != NULL)
  			*mapp = map;
  		return map__find_symbol(map, map->map_ip(map, addr));
  	}
  
  	return NULL;
  }
  
  static bool map__contains_symbol(struct map *map, struct symbol *sym)
  {
  	u64 ip = map->unmap_ip(map, sym->start);
  
  	return ip >= map->start && ip < map->end;
  }
  
  struct symbol *maps__find_symbol_by_name(struct maps *maps, const char *name,
  					 struct map **mapp)
  {
  	struct symbol *sym;
  	struct rb_node *nd;
  
  	down_read(&maps->lock);
  
  	for (nd = rb_first(&maps->entries); nd; nd = rb_next(nd)) {
  		struct map *pos = rb_entry(nd, struct map, rb_node);
  
  		sym = map__find_symbol_by_name(pos, name);
  
  		if (sym == NULL)
  			continue;
  		if (!map__contains_symbol(pos, sym)) {
  			sym = NULL;
  			continue;
  		}
  		if (mapp != NULL)
  			*mapp = pos;
  		goto out;
  	}
  
  	sym = NULL;
  out:
  	up_read(&maps->lock);
  	return sym;
  }
  
  struct symbol *map_groups__find_symbol_by_name(struct map_groups *mg,
  					       const char *name,
  					       struct map **mapp)
  {
  	return maps__find_symbol_by_name(&mg->maps, name, mapp);
  }
  
  int map_groups__find_ams(struct addr_map_symbol *ams)
  {
  	if (ams->addr < ams->map->start || ams->addr >= ams->map->end) {
  		if (ams->map->groups == NULL)
  			return -1;
  		ams->map = map_groups__find(ams->map->groups, ams->addr);
  		if (ams->map == NULL)
  			return -1;
  	}
  
  	ams->al_addr = ams->map->map_ip(ams->map, ams->addr);
  	ams->sym = map__find_symbol(ams->map, ams->al_addr);
  
  	return ams->sym ? 0 : -1;
  }
  
  static size_t maps__fprintf(struct maps *maps, FILE *fp)
  {
  	size_t printed = 0;
  	struct rb_node *nd;
  
  	down_read(&maps->lock);
  
  	for (nd = rb_first(&maps->entries); nd; nd = rb_next(nd)) {
  		struct map *pos = rb_entry(nd, struct map, rb_node);
  		printed += fprintf(fp, "Map:");
  		printed += map__fprintf(pos, fp);
  		if (verbose > 2) {
  			printed += dso__fprintf(pos->dso, fp);
  			printed += fprintf(fp, "--\n");
  		}
  	}
  
  	up_read(&maps->lock);
  
  	return printed;
  }
  
  size_t map_groups__fprintf(struct map_groups *mg, FILE *fp)
  {
  	return maps__fprintf(&mg->maps, fp);
  }
  
  static void __map_groups__insert(struct map_groups *mg, struct map *map)
  {
  	__maps__insert(&mg->maps, map);
  	map->groups = mg;
  }
  
  static int maps__fixup_overlappings(struct maps *maps, struct map *map, FILE *fp)
  {
  	struct rb_root *root;
  	struct rb_node *next, *first;
  	int err = 0;
  
  	down_write(&maps->lock);
  
  	root = &maps->entries;
  
  	/*
  	 * Find first map where end > map->start.
  	 * Same as find_vma() in kernel.
  	 */
  	next = root->rb_node;
  	first = NULL;
  	while (next) {
  		struct map *pos = rb_entry(next, struct map, rb_node);
  
  		if (pos->end > map->start) {
  			first = next;
  			if (pos->start <= map->start)
  				break;
  			next = next->rb_left;
  		} else
  			next = next->rb_right;
  	}
  
  	next = first;
  	while (next) {
  		struct map *pos = rb_entry(next, struct map, rb_node);
  		next = rb_next(&pos->rb_node);
  
  		/*
  		 * Stop if current map starts after map->end.
  		 * Maps are ordered by start: next will not overlap for sure.
  		 */
  		if (pos->start >= map->end)
  			break;
  
  		if (verbose >= 2) {
  
  			if (use_browser) {
  				pr_debug("overlapping maps in %s (disable tui for more info)\n",
  					   map->dso->name);
  			} else {
  				fputs("overlapping maps:\n", fp);
  				map__fprintf(map, fp);
  				map__fprintf(pos, fp);
  			}
  		}
  
  		rb_erase_init(&pos->rb_node, root);
  		/*
  		 * Now check if we need to create new maps for areas not
  		 * overlapped by the new map:
  		 */
  		if (map->start > pos->start) {
  			struct map *before = map__clone(pos);
  
  			if (before == NULL) {
  				err = -ENOMEM;
  				goto put_map;
  			}
  
  			before->end = map->start;
  			__map_groups__insert(pos->groups, before);
  			if (verbose >= 2 && !use_browser)
  				map__fprintf(before, fp);
  			map__put(before);
  		}
  
  		if (map->end < pos->end) {
  			struct map *after = map__clone(pos);
  
  			if (after == NULL) {
  				err = -ENOMEM;
  				goto put_map;
  			}
  
  			after->start = map->end;
  			__map_groups__insert(pos->groups, after);
  			if (verbose >= 2 && !use_browser)
  				map__fprintf(after, fp);
  			map__put(after);
  		}
  put_map:
  		map__put(pos);
  
  		if (err)
  			goto out;
  	}
  
  	err = 0;
  out:
  	up_write(&maps->lock);
  	return err;
  }
  
  int map_groups__fixup_overlappings(struct map_groups *mg, struct map *map,
  				   FILE *fp)
  {
  	return maps__fixup_overlappings(&mg->maps, map, fp);
  }
  
  /*
   * XXX This should not really _copy_ te maps, but refcount them.
   */
  int map_groups__clone(struct thread *thread, struct map_groups *parent)
  {
  	struct map_groups *mg = thread->mg;
  	int err = -ENOMEM;
  	struct map *map;
  	struct maps *maps = &parent->maps;
  
  	down_read(&maps->lock);
  
  	for (map = maps__first(maps); map; map = map__next(map)) {
  		struct map *new = map__clone(map);
  		if (new == NULL)
  			goto out_unlock;
  
  		err = unwind__prepare_access(thread, new, NULL);
  		if (err)
  			goto out_unlock;
  
  		map_groups__insert(mg, new);
  		map__put(new);
  	}
  
  	err = 0;
  out_unlock:
  	up_read(&maps->lock);
  	return err;
  }
  
  static void __maps__insert(struct maps *maps, struct map *map)
  {
  	struct rb_node **p = &maps->entries.rb_node;
  	struct rb_node *parent = NULL;
  	const u64 ip = map->start;
  	struct map *m;
  
  	while (*p != NULL) {
  		parent = *p;
  		m = rb_entry(parent, struct map, rb_node);
  		if (ip < m->start)
  			p = &(*p)->rb_left;
  		else
  			p = &(*p)->rb_right;
  	}
  
  	rb_link_node(&map->rb_node, parent, p);
  	rb_insert_color(&map->rb_node, &maps->entries);
  	map__get(map);
  }
  
  void maps__insert(struct maps *maps, struct map *map)
  {
  	down_write(&maps->lock);
  	__maps__insert(maps, map);
  	up_write(&maps->lock);
  }
  
  static void __maps__remove(struct maps *maps, struct map *map)
  {
  	rb_erase_init(&map->rb_node, &maps->entries);
  	map__put(map);
  }
  
  void maps__remove(struct maps *maps, struct map *map)
  {
  	down_write(&maps->lock);
  	__maps__remove(maps, map);
  	up_write(&maps->lock);
  }
  
  struct map *maps__find(struct maps *maps, u64 ip)
  {
  	struct rb_node **p, *parent = NULL;
  	struct map *m;
  
  	down_read(&maps->lock);
  
  	p = &maps->entries.rb_node;
  	while (*p != NULL) {
  		parent = *p;
  		m = rb_entry(parent, struct map, rb_node);
  		if (ip < m->start)
  			p = &(*p)->rb_left;
  		else if (ip >= m->end)
  			p = &(*p)->rb_right;
  		else
  			goto out;
  	}
  
  	m = NULL;
  out:
  	up_read(&maps->lock);
  	return m;
  }
  
  struct map *maps__first(struct maps *maps)
  {
  	struct rb_node *first = rb_first(&maps->entries);
  
  	if (first)
  		return rb_entry(first, struct map, rb_node);
  	return NULL;
  }
  
  struct map *map__next(struct map *map)
  {
  	struct rb_node *next = rb_next(&map->rb_node);
  
  	if (next)
  		return rb_entry(next, struct map, rb_node);
  	return NULL;
  }
  
  struct kmap *__map__kmap(struct map *map)
  {
  	if (!map->dso || !map->dso->kernel)
  		return NULL;
  	return (struct kmap *)(map + 1);
  }
  
  struct kmap *map__kmap(struct map *map)
  {
  	struct kmap *kmap = __map__kmap(map);
  
  	if (!kmap)
  		pr_err("Internal error: map__kmap with a non-kernel map\n");
  	return kmap;
  }
  
  struct map_groups *map__kmaps(struct map *map)
  {
  	struct kmap *kmap = map__kmap(map);
  
  	if (!kmap || !kmap->kmaps) {
  		pr_err("Internal error: map__kmaps with a non-kernel map\n");
  		return NULL;
  	}
  	return kmap->kmaps;
  }
  