summaryrefslogtreecommitdiff
path: root/tools/perf/util/map.c
blob: 95428511300d1e371c756846fbdfd3b415e94782 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
// SPDX-License-Identifier: GPL-2.0
#include "symbol.h"
#include <assert.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 "dso.h"
#include "map.h"
#include "map_symbol.h"
#include "thread.h"
#include "vdso.h"
#include "build-id.h"
#include "debug.h"
#include "machine.h"
#include <linux/string.h>
#include <linux/zalloc.h>
#include "srcline.h"
#include "namespaces.h"
#include "unwind.h"
#include "srccode.h"
#include "ui/ui.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->erange_warned = false;
	refcount_set(&map->refcnt, 1);
}

struct map *map__new(struct machine *machine, u64 start, u64 len,
		     u64 pgoff, struct dso_id *id,
		     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->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_id(machine, filename, id);

		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;
}

bool __map__is_kernel(const struct map *map)
{
	if (!map->dso->kernel)
		return false;
	return machine__kernel_map(map__kmaps((struct map *)map)->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__is_bpf_prog(const struct map *map)
{
	const char *name;

	if (map->dso->binary_type == DSO_BINARY_TYPE__BPF_PROG_INFO)
		return true;

	/*
	 * If PERF_RECORD_BPF_EVENT is not included, the dso will not have
	 * type of DSO_BINARY_TYPE__BPF_PROG_INFO. In such cases, we can
	 * guess the type based on name.
	 */
	name = map->dso->short_name;
	return name && (strstr(name, "bpf_prog_") == name);
}

bool map__has_symbols(const struct map *map)
{
	return dso__has_symbols(map->dso);
}

static void map__exit(struct map *map)
{
	BUG_ON(refcount_read(&map->refcnt) != 0);
	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_cached *symbols = &map->dso->symbols;
	struct rb_node *nd = rb_first_cached(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_cached *symbols = &map->dso->symbols;
	struct rb_node *nd = rb_last(&symbols->rb_root);
	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)
{
	size_t size = sizeof(struct map);
	struct map *map;

	if (from->dso && from->dso->kernel)
		size += sizeof(struct kmap);

	map = memdup(from, size);
	if (map != NULL) {
		refcount_set(&map->refcnt, 1);
		RB_CLEAR_NODE(&map->rb_node);
		dso__get(map->dso);
	}

	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)
{
	char buf[symbol_conf.pad_output_len_dso + 1];
	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;
	}

	if (symbol_conf.pad_output_len_dso) {
		scnprintf_pad(buf, symbol_conf.pad_output_len_dso, "%s", dsoname);
		dsoname = buf;
	}

	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 (strncmp(srcline, SRCLINE_UNKNOWN, strlen(SRCLINE_UNKNOWN)) != 0)
			ret = fprintf(fp, "%s%s", prefix, srcline);
		free_srcline(srcline);
	}
	return ret;
}

void srccode_state_free(struct srccode_state *state)
{
	zfree(&state->srcfile);
	state->line = 0;
}

/**
 * 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;
}

void maps__init(struct maps *maps, struct machine *machine)
{
	maps->entries = RB_ROOT;
	init_rwsem(&maps->lock);
	maps->machine = machine;
	maps->last_search_by_name = NULL;
	maps->nr_maps = 0;
	maps->maps_by_name = NULL;
	refcount_set(&maps->refcnt, 1);
}

static void __maps__free_maps_by_name(struct maps *maps)
{
	/*
	 * Free everything to try to do it from the rbtree in the next search
	 */
	zfree(&maps->maps_by_name);
	maps->nr_maps_allocated = 0;
}

void maps__insert(struct maps *maps, struct map *map)
{
	down_write(&maps->lock);
	__maps__insert(maps, map);
	++maps->nr_maps;

	if (map->dso && map->dso->kernel) {
		struct kmap *kmap = map__kmap(map);

		if (kmap)
			kmap->kmaps = maps;
		else
			pr_err("Internal error: kernel dso with non kernel map\n");
	}


	/*
	 * If we already performed some search by name, then we need to add the just
	 * inserted map and resort.
	 */
	if (maps->maps_by_name) {
		if (maps->nr_maps > maps->nr_maps_allocated) {
			int nr_allocate = maps->nr_maps * 2;
			struct map **maps_by_name = realloc(maps->maps_by_name, nr_allocate * sizeof(map));

			if (maps_by_name == NULL) {
				__maps__free_maps_by_name(maps);
				up_write(&maps->lock);
				return;
			}

			maps->maps_by_name = maps_by_name;
			maps->nr_maps_allocated = nr_allocate;
		}
		maps->maps_by_name[maps->nr_maps - 1] = map;
		__maps__sort_by_name(maps);
	}
	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);
	if (maps->last_search_by_name == map)
		maps->last_search_by_name = NULL;

	__maps__remove(maps, map);
	--maps->nr_maps;
	if (maps->maps_by_name)
		__maps__free_maps_by_name(maps);
	up_write(&maps->lock);
}

static void __maps__purge(struct maps *maps)
{
	struct map *pos, *next;

	maps__for_each_entry_safe(maps, pos, next) {
		rb_erase_init(&pos->rb_node,  &maps->entries);
		map__put(pos);
	}
}

void maps__exit(struct maps *maps)
{
	down_write(&maps->lock);
	__maps__purge(maps);
	up_write(&maps->lock);
}

bool maps__empty(struct maps *maps)
{
	return !maps__first(maps);
}

struct maps *maps__new(struct machine *machine)
{
	struct maps *maps = zalloc(sizeof(*maps));

	if (maps != NULL)
		maps__init(maps, machine);

	return maps;
}

void maps__delete(struct maps *maps)
{
	maps__exit(maps);
	unwind__finish_access(maps);
	free(maps);
}

void maps__put(struct maps *maps)
{
	if (maps && refcount_dec_and_test(&maps->refcnt))
		maps__delete(maps);
}

struct symbol *maps__find_symbol(struct maps *maps, u64 addr, struct map **mapp)
{
	struct map *map = maps__find(maps, 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 map *pos;

	down_read(&maps->lock);

	maps__for_each_entry(maps, pos) {
		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;
}

int maps__find_ams(struct maps *maps, struct addr_map_symbol *ams)
{
	if (ams->addr < ams->ms.map->start || ams->addr >= ams->ms.map->end) {
		if (maps == NULL)
			return -1;
		ams->ms.map = maps__find(maps, ams->addr);
		if (ams->ms.map == NULL)
			return -1;
	}

	ams->al_addr = ams->ms.map->map_ip(ams->ms.map, ams->addr);
	ams->ms.sym = map__find_symbol(ams->ms.map, ams->al_addr);

	return ams->ms.sym ? 0 : -1;
}

size_t maps__fprintf(struct maps *maps, FILE *fp)
{
	size_t printed = 0;
	struct map *pos;

	down_read(&maps->lock);

	maps__for_each_entry(maps, pos) {
		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;
}

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;
			__maps__insert(maps, 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;
			after->pgoff += map->end - pos->start;
			assert(pos->map_ip(pos, map->end) == after->map_ip(after, map->end));
			__maps__insert(maps, 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;
}

/*
 * XXX This should not really _copy_ te maps, but refcount them.
 */
int maps__clone(struct thread *thread, struct maps *parent)
{
	struct maps *maps = thread->maps;
	int err = -ENOMEM;
	struct map *map;

	down_read(&parent->lock);

	maps__for_each_entry(parent, map) {
		struct map *new = map__clone(map);
		if (new == NULL)
			goto out_unlock;

		err = unwind__prepare_access(maps, new, NULL);
		if (err)
			goto out_unlock;

		maps__insert(maps, new);
		map__put(new);
	}

	err = 0;
out_unlock:
	up_read(&parent->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);
}

struct map *maps__find(struct maps *maps, u64 ip)
{
	struct rb_node *p;
	struct map *m;

	down_read(&maps->lock);

	p = maps->entries.rb_node;
	while (p != NULL) {
		m = rb_entry(p, 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;
}

static 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 map *map__next(struct map *map)
{
	return map ? __map__next(map) : 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 maps *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;
}