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Merge remote-tracking branch 'spi/for-next'
[deliverable/linux.git] / tools / perf / util / symbol-elf.c
1 #include <fcntl.h>
2 #include <stdio.h>
3 #include <errno.h>
4 #include <string.h>
5 #include <unistd.h>
6 #include <inttypes.h>
7
8 #include "symbol.h"
9 #include "demangle-java.h"
10 #include "demangle-rust.h"
11 #include "machine.h"
12 #include "vdso.h"
13 #include <symbol/kallsyms.h>
14 #include "debug.h"
15
16 #ifndef EM_AARCH64
17 #define EM_AARCH64 183 /* ARM 64 bit */
18 #endif
19
20 typedef Elf64_Nhdr GElf_Nhdr;
21
22 #ifdef HAVE_CPLUS_DEMANGLE_SUPPORT
23 extern char *cplus_demangle(const char *, int);
24
25 static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i)
26 {
27 return cplus_demangle(c, i);
28 }
29 #else
30 #ifdef NO_DEMANGLE
31 static inline char *bfd_demangle(void __maybe_unused *v,
32 const char __maybe_unused *c,
33 int __maybe_unused i)
34 {
35 return NULL;
36 }
37 #else
38 #define PACKAGE 'perf'
39 #include <bfd.h>
40 #endif
41 #endif
42
43 #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
44 static int elf_getphdrnum(Elf *elf, size_t *dst)
45 {
46 GElf_Ehdr gehdr;
47 GElf_Ehdr *ehdr;
48
49 ehdr = gelf_getehdr(elf, &gehdr);
50 if (!ehdr)
51 return -1;
52
53 *dst = ehdr->e_phnum;
54
55 return 0;
56 }
57 #endif
58
59 #ifndef HAVE_ELF_GETSHDRSTRNDX_SUPPORT
60 static int elf_getshdrstrndx(Elf *elf __maybe_unused, size_t *dst __maybe_unused)
61 {
62 pr_err("%s: update your libelf to > 0.140, this one lacks elf_getshdrstrndx().\n", __func__);
63 return -1;
64 }
65 #endif
66
67 #ifndef NT_GNU_BUILD_ID
68 #define NT_GNU_BUILD_ID 3
69 #endif
70
71 /**
72 * elf_symtab__for_each_symbol - iterate thru all the symbols
73 *
74 * @syms: struct elf_symtab instance to iterate
75 * @idx: uint32_t idx
76 * @sym: GElf_Sym iterator
77 */
78 #define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
79 for (idx = 0, gelf_getsym(syms, idx, &sym);\
80 idx < nr_syms; \
81 idx++, gelf_getsym(syms, idx, &sym))
82
83 static inline uint8_t elf_sym__type(const GElf_Sym *sym)
84 {
85 return GELF_ST_TYPE(sym->st_info);
86 }
87
88 #ifndef STT_GNU_IFUNC
89 #define STT_GNU_IFUNC 10
90 #endif
91
92 static inline int elf_sym__is_function(const GElf_Sym *sym)
93 {
94 return (elf_sym__type(sym) == STT_FUNC ||
95 elf_sym__type(sym) == STT_GNU_IFUNC) &&
96 sym->st_name != 0 &&
97 sym->st_shndx != SHN_UNDEF;
98 }
99
100 static inline bool elf_sym__is_object(const GElf_Sym *sym)
101 {
102 return elf_sym__type(sym) == STT_OBJECT &&
103 sym->st_name != 0 &&
104 sym->st_shndx != SHN_UNDEF;
105 }
106
107 static inline int elf_sym__is_label(const GElf_Sym *sym)
108 {
109 return elf_sym__type(sym) == STT_NOTYPE &&
110 sym->st_name != 0 &&
111 sym->st_shndx != SHN_UNDEF &&
112 sym->st_shndx != SHN_ABS;
113 }
114
115 static bool elf_sym__is_a(GElf_Sym *sym, enum map_type type)
116 {
117 switch (type) {
118 case MAP__FUNCTION:
119 return elf_sym__is_function(sym);
120 case MAP__VARIABLE:
121 return elf_sym__is_object(sym);
122 default:
123 return false;
124 }
125 }
126
127 static inline const char *elf_sym__name(const GElf_Sym *sym,
128 const Elf_Data *symstrs)
129 {
130 return symstrs->d_buf + sym->st_name;
131 }
132
133 static inline const char *elf_sec__name(const GElf_Shdr *shdr,
134 const Elf_Data *secstrs)
135 {
136 return secstrs->d_buf + shdr->sh_name;
137 }
138
139 static inline int elf_sec__is_text(const GElf_Shdr *shdr,
140 const Elf_Data *secstrs)
141 {
142 return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
143 }
144
145 static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
146 const Elf_Data *secstrs)
147 {
148 return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
149 }
150
151 static bool elf_sec__is_a(GElf_Shdr *shdr, Elf_Data *secstrs,
152 enum map_type type)
153 {
154 switch (type) {
155 case MAP__FUNCTION:
156 return elf_sec__is_text(shdr, secstrs);
157 case MAP__VARIABLE:
158 return elf_sec__is_data(shdr, secstrs);
159 default:
160 return false;
161 }
162 }
163
164 static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
165 {
166 Elf_Scn *sec = NULL;
167 GElf_Shdr shdr;
168 size_t cnt = 1;
169
170 while ((sec = elf_nextscn(elf, sec)) != NULL) {
171 gelf_getshdr(sec, &shdr);
172
173 if ((addr >= shdr.sh_addr) &&
174 (addr < (shdr.sh_addr + shdr.sh_size)))
175 return cnt;
176
177 ++cnt;
178 }
179
180 return -1;
181 }
182
183 Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
184 GElf_Shdr *shp, const char *name, size_t *idx)
185 {
186 Elf_Scn *sec = NULL;
187 size_t cnt = 1;
188
189 /* Elf is corrupted/truncated, avoid calling elf_strptr. */
190 if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
191 return NULL;
192
193 while ((sec = elf_nextscn(elf, sec)) != NULL) {
194 char *str;
195
196 gelf_getshdr(sec, shp);
197 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
198 if (str && !strcmp(name, str)) {
199 if (idx)
200 *idx = cnt;
201 return sec;
202 }
203 ++cnt;
204 }
205
206 return NULL;
207 }
208
209 #define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
210 for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
211 idx < nr_entries; \
212 ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
213
214 #define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
215 for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
216 idx < nr_entries; \
217 ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
218
219 /*
220 * We need to check if we have a .dynsym, so that we can handle the
221 * .plt, synthesizing its symbols, that aren't on the symtabs (be it
222 * .dynsym or .symtab).
223 * And always look at the original dso, not at debuginfo packages, that
224 * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
225 */
226 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss, struct map *map,
227 symbol_filter_t filter)
228 {
229 uint32_t nr_rel_entries, idx;
230 GElf_Sym sym;
231 u64 plt_offset;
232 GElf_Shdr shdr_plt;
233 struct symbol *f;
234 GElf_Shdr shdr_rel_plt, shdr_dynsym;
235 Elf_Data *reldata, *syms, *symstrs;
236 Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
237 size_t dynsym_idx;
238 GElf_Ehdr ehdr;
239 char sympltname[1024];
240 Elf *elf;
241 int nr = 0, symidx, err = 0;
242
243 if (!ss->dynsym)
244 return 0;
245
246 elf = ss->elf;
247 ehdr = ss->ehdr;
248
249 scn_dynsym = ss->dynsym;
250 shdr_dynsym = ss->dynshdr;
251 dynsym_idx = ss->dynsym_idx;
252
253 if (scn_dynsym == NULL)
254 goto out_elf_end;
255
256 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
257 ".rela.plt", NULL);
258 if (scn_plt_rel == NULL) {
259 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
260 ".rel.plt", NULL);
261 if (scn_plt_rel == NULL)
262 goto out_elf_end;
263 }
264
265 err = -1;
266
267 if (shdr_rel_plt.sh_link != dynsym_idx)
268 goto out_elf_end;
269
270 if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
271 goto out_elf_end;
272
273 /*
274 * Fetch the relocation section to find the idxes to the GOT
275 * and the symbols in the .dynsym they refer to.
276 */
277 reldata = elf_getdata(scn_plt_rel, NULL);
278 if (reldata == NULL)
279 goto out_elf_end;
280
281 syms = elf_getdata(scn_dynsym, NULL);
282 if (syms == NULL)
283 goto out_elf_end;
284
285 scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
286 if (scn_symstrs == NULL)
287 goto out_elf_end;
288
289 symstrs = elf_getdata(scn_symstrs, NULL);
290 if (symstrs == NULL)
291 goto out_elf_end;
292
293 if (symstrs->d_size == 0)
294 goto out_elf_end;
295
296 nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
297 plt_offset = shdr_plt.sh_offset;
298
299 if (shdr_rel_plt.sh_type == SHT_RELA) {
300 GElf_Rela pos_mem, *pos;
301
302 elf_section__for_each_rela(reldata, pos, pos_mem, idx,
303 nr_rel_entries) {
304 symidx = GELF_R_SYM(pos->r_info);
305 plt_offset += shdr_plt.sh_entsize;
306 gelf_getsym(syms, symidx, &sym);
307 snprintf(sympltname, sizeof(sympltname),
308 "%s@plt", elf_sym__name(&sym, symstrs));
309
310 f = symbol__new(plt_offset, shdr_plt.sh_entsize,
311 STB_GLOBAL, sympltname);
312 if (!f)
313 goto out_elf_end;
314
315 if (filter && filter(map, f))
316 symbol__delete(f);
317 else {
318 symbols__insert(&dso->symbols[map->type], f);
319 ++nr;
320 }
321 }
322 } else if (shdr_rel_plt.sh_type == SHT_REL) {
323 GElf_Rel pos_mem, *pos;
324 elf_section__for_each_rel(reldata, pos, pos_mem, idx,
325 nr_rel_entries) {
326 symidx = GELF_R_SYM(pos->r_info);
327 plt_offset += shdr_plt.sh_entsize;
328 gelf_getsym(syms, symidx, &sym);
329 snprintf(sympltname, sizeof(sympltname),
330 "%s@plt", elf_sym__name(&sym, symstrs));
331
332 f = symbol__new(plt_offset, shdr_plt.sh_entsize,
333 STB_GLOBAL, sympltname);
334 if (!f)
335 goto out_elf_end;
336
337 if (filter && filter(map, f))
338 symbol__delete(f);
339 else {
340 symbols__insert(&dso->symbols[map->type], f);
341 ++nr;
342 }
343 }
344 }
345
346 err = 0;
347 out_elf_end:
348 if (err == 0)
349 return nr;
350 pr_debug("%s: problems reading %s PLT info.\n",
351 __func__, dso->long_name);
352 return 0;
353 }
354
355 /*
356 * Align offset to 4 bytes as needed for note name and descriptor data.
357 */
358 #define NOTE_ALIGN(n) (((n) + 3) & -4U)
359
360 static int elf_read_build_id(Elf *elf, void *bf, size_t size)
361 {
362 int err = -1;
363 GElf_Ehdr ehdr;
364 GElf_Shdr shdr;
365 Elf_Data *data;
366 Elf_Scn *sec;
367 Elf_Kind ek;
368 void *ptr;
369
370 if (size < BUILD_ID_SIZE)
371 goto out;
372
373 ek = elf_kind(elf);
374 if (ek != ELF_K_ELF)
375 goto out;
376
377 if (gelf_getehdr(elf, &ehdr) == NULL) {
378 pr_err("%s: cannot get elf header.\n", __func__);
379 goto out;
380 }
381
382 /*
383 * Check following sections for notes:
384 * '.note.gnu.build-id'
385 * '.notes'
386 * '.note' (VDSO specific)
387 */
388 do {
389 sec = elf_section_by_name(elf, &ehdr, &shdr,
390 ".note.gnu.build-id", NULL);
391 if (sec)
392 break;
393
394 sec = elf_section_by_name(elf, &ehdr, &shdr,
395 ".notes", NULL);
396 if (sec)
397 break;
398
399 sec = elf_section_by_name(elf, &ehdr, &shdr,
400 ".note", NULL);
401 if (sec)
402 break;
403
404 return err;
405
406 } while (0);
407
408 data = elf_getdata(sec, NULL);
409 if (data == NULL)
410 goto out;
411
412 ptr = data->d_buf;
413 while (ptr < (data->d_buf + data->d_size)) {
414 GElf_Nhdr *nhdr = ptr;
415 size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
416 descsz = NOTE_ALIGN(nhdr->n_descsz);
417 const char *name;
418
419 ptr += sizeof(*nhdr);
420 name = ptr;
421 ptr += namesz;
422 if (nhdr->n_type == NT_GNU_BUILD_ID &&
423 nhdr->n_namesz == sizeof("GNU")) {
424 if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
425 size_t sz = min(size, descsz);
426 memcpy(bf, ptr, sz);
427 memset(bf + sz, 0, size - sz);
428 err = descsz;
429 break;
430 }
431 }
432 ptr += descsz;
433 }
434
435 out:
436 return err;
437 }
438
439 int filename__read_build_id(const char *filename, void *bf, size_t size)
440 {
441 int fd, err = -1;
442 Elf *elf;
443
444 if (size < BUILD_ID_SIZE)
445 goto out;
446
447 fd = open(filename, O_RDONLY);
448 if (fd < 0)
449 goto out;
450
451 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
452 if (elf == NULL) {
453 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
454 goto out_close;
455 }
456
457 err = elf_read_build_id(elf, bf, size);
458
459 elf_end(elf);
460 out_close:
461 close(fd);
462 out:
463 return err;
464 }
465
466 int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
467 {
468 int fd, err = -1;
469
470 if (size < BUILD_ID_SIZE)
471 goto out;
472
473 fd = open(filename, O_RDONLY);
474 if (fd < 0)
475 goto out;
476
477 while (1) {
478 char bf[BUFSIZ];
479 GElf_Nhdr nhdr;
480 size_t namesz, descsz;
481
482 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
483 break;
484
485 namesz = NOTE_ALIGN(nhdr.n_namesz);
486 descsz = NOTE_ALIGN(nhdr.n_descsz);
487 if (nhdr.n_type == NT_GNU_BUILD_ID &&
488 nhdr.n_namesz == sizeof("GNU")) {
489 if (read(fd, bf, namesz) != (ssize_t)namesz)
490 break;
491 if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
492 size_t sz = min(descsz, size);
493 if (read(fd, build_id, sz) == (ssize_t)sz) {
494 memset(build_id + sz, 0, size - sz);
495 err = 0;
496 break;
497 }
498 } else if (read(fd, bf, descsz) != (ssize_t)descsz)
499 break;
500 } else {
501 int n = namesz + descsz;
502 if (read(fd, bf, n) != n)
503 break;
504 }
505 }
506 close(fd);
507 out:
508 return err;
509 }
510
511 int filename__read_debuglink(const char *filename, char *debuglink,
512 size_t size)
513 {
514 int fd, err = -1;
515 Elf *elf;
516 GElf_Ehdr ehdr;
517 GElf_Shdr shdr;
518 Elf_Data *data;
519 Elf_Scn *sec;
520 Elf_Kind ek;
521
522 fd = open(filename, O_RDONLY);
523 if (fd < 0)
524 goto out;
525
526 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
527 if (elf == NULL) {
528 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
529 goto out_close;
530 }
531
532 ek = elf_kind(elf);
533 if (ek != ELF_K_ELF)
534 goto out_elf_end;
535
536 if (gelf_getehdr(elf, &ehdr) == NULL) {
537 pr_err("%s: cannot get elf header.\n", __func__);
538 goto out_elf_end;
539 }
540
541 sec = elf_section_by_name(elf, &ehdr, &shdr,
542 ".gnu_debuglink", NULL);
543 if (sec == NULL)
544 goto out_elf_end;
545
546 data = elf_getdata(sec, NULL);
547 if (data == NULL)
548 goto out_elf_end;
549
550 /* the start of this section is a zero-terminated string */
551 strncpy(debuglink, data->d_buf, size);
552
553 err = 0;
554
555 out_elf_end:
556 elf_end(elf);
557 out_close:
558 close(fd);
559 out:
560 return err;
561 }
562
563 static int dso__swap_init(struct dso *dso, unsigned char eidata)
564 {
565 static unsigned int const endian = 1;
566
567 dso->needs_swap = DSO_SWAP__NO;
568
569 switch (eidata) {
570 case ELFDATA2LSB:
571 /* We are big endian, DSO is little endian. */
572 if (*(unsigned char const *)&endian != 1)
573 dso->needs_swap = DSO_SWAP__YES;
574 break;
575
576 case ELFDATA2MSB:
577 /* We are little endian, DSO is big endian. */
578 if (*(unsigned char const *)&endian != 0)
579 dso->needs_swap = DSO_SWAP__YES;
580 break;
581
582 default:
583 pr_err("unrecognized DSO data encoding %d\n", eidata);
584 return -EINVAL;
585 }
586
587 return 0;
588 }
589
590 static int decompress_kmodule(struct dso *dso, const char *name,
591 enum dso_binary_type type)
592 {
593 int fd = -1;
594 char tmpbuf[] = "/tmp/perf-kmod-XXXXXX";
595 struct kmod_path m;
596
597 if (type != DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP &&
598 type != DSO_BINARY_TYPE__GUEST_KMODULE_COMP &&
599 type != DSO_BINARY_TYPE__BUILD_ID_CACHE)
600 return -1;
601
602 if (type == DSO_BINARY_TYPE__BUILD_ID_CACHE)
603 name = dso->long_name;
604
605 if (kmod_path__parse_ext(&m, name) || !m.comp)
606 return -1;
607
608 fd = mkstemp(tmpbuf);
609 if (fd < 0) {
610 dso->load_errno = errno;
611 goto out;
612 }
613
614 if (!decompress_to_file(m.ext, name, fd)) {
615 dso->load_errno = DSO_LOAD_ERRNO__DECOMPRESSION_FAILURE;
616 close(fd);
617 fd = -1;
618 }
619
620 unlink(tmpbuf);
621
622 out:
623 free(m.ext);
624 return fd;
625 }
626
627 bool symsrc__possibly_runtime(struct symsrc *ss)
628 {
629 return ss->dynsym || ss->opdsec;
630 }
631
632 bool symsrc__has_symtab(struct symsrc *ss)
633 {
634 return ss->symtab != NULL;
635 }
636
637 void symsrc__destroy(struct symsrc *ss)
638 {
639 zfree(&ss->name);
640 elf_end(ss->elf);
641 close(ss->fd);
642 }
643
644 bool __weak elf__needs_adjust_symbols(GElf_Ehdr ehdr)
645 {
646 return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL;
647 }
648
649 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
650 enum dso_binary_type type)
651 {
652 int err = -1;
653 GElf_Ehdr ehdr;
654 Elf *elf;
655 int fd;
656
657 if (dso__needs_decompress(dso)) {
658 fd = decompress_kmodule(dso, name, type);
659 if (fd < 0)
660 return -1;
661 } else {
662 fd = open(name, O_RDONLY);
663 if (fd < 0) {
664 dso->load_errno = errno;
665 return -1;
666 }
667 }
668
669 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
670 if (elf == NULL) {
671 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
672 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
673 goto out_close;
674 }
675
676 if (gelf_getehdr(elf, &ehdr) == NULL) {
677 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
678 pr_debug("%s: cannot get elf header.\n", __func__);
679 goto out_elf_end;
680 }
681
682 if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
683 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
684 goto out_elf_end;
685 }
686
687 /* Always reject images with a mismatched build-id: */
688 if (dso->has_build_id) {
689 u8 build_id[BUILD_ID_SIZE];
690
691 if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) {
692 dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
693 goto out_elf_end;
694 }
695
696 if (!dso__build_id_equal(dso, build_id)) {
697 pr_debug("%s: build id mismatch for %s.\n", __func__, name);
698 dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
699 goto out_elf_end;
700 }
701 }
702
703 ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
704
705 ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
706 NULL);
707 if (ss->symshdr.sh_type != SHT_SYMTAB)
708 ss->symtab = NULL;
709
710 ss->dynsym_idx = 0;
711 ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
712 &ss->dynsym_idx);
713 if (ss->dynshdr.sh_type != SHT_DYNSYM)
714 ss->dynsym = NULL;
715
716 ss->opdidx = 0;
717 ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
718 &ss->opdidx);
719 if (ss->opdshdr.sh_type != SHT_PROGBITS)
720 ss->opdsec = NULL;
721
722 if (dso->kernel == DSO_TYPE_USER)
723 ss->adjust_symbols = true;
724 else
725 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
726
727 ss->name = strdup(name);
728 if (!ss->name) {
729 dso->load_errno = errno;
730 goto out_elf_end;
731 }
732
733 ss->elf = elf;
734 ss->fd = fd;
735 ss->ehdr = ehdr;
736 ss->type = type;
737
738 return 0;
739
740 out_elf_end:
741 elf_end(elf);
742 out_close:
743 close(fd);
744 return err;
745 }
746
747 /**
748 * ref_reloc_sym_not_found - has kernel relocation symbol been found.
749 * @kmap: kernel maps and relocation reference symbol
750 *
751 * This function returns %true if we are dealing with the kernel maps and the
752 * relocation reference symbol has not yet been found. Otherwise %false is
753 * returned.
754 */
755 static bool ref_reloc_sym_not_found(struct kmap *kmap)
756 {
757 return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
758 !kmap->ref_reloc_sym->unrelocated_addr;
759 }
760
761 /**
762 * ref_reloc - kernel relocation offset.
763 * @kmap: kernel maps and relocation reference symbol
764 *
765 * This function returns the offset of kernel addresses as determined by using
766 * the relocation reference symbol i.e. if the kernel has not been relocated
767 * then the return value is zero.
768 */
769 static u64 ref_reloc(struct kmap *kmap)
770 {
771 if (kmap && kmap->ref_reloc_sym &&
772 kmap->ref_reloc_sym->unrelocated_addr)
773 return kmap->ref_reloc_sym->addr -
774 kmap->ref_reloc_sym->unrelocated_addr;
775 return 0;
776 }
777
778 static bool want_demangle(bool is_kernel_sym)
779 {
780 return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
781 }
782
783 void __weak arch__sym_update(struct symbol *s __maybe_unused,
784 GElf_Sym *sym __maybe_unused) { }
785
786 int dso__load_sym(struct dso *dso, struct map *map,
787 struct symsrc *syms_ss, struct symsrc *runtime_ss,
788 symbol_filter_t filter, int kmodule)
789 {
790 struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
791 struct map_groups *kmaps = kmap ? map__kmaps(map) : NULL;
792 struct map *curr_map = map;
793 struct dso *curr_dso = dso;
794 Elf_Data *symstrs, *secstrs;
795 uint32_t nr_syms;
796 int err = -1;
797 uint32_t idx;
798 GElf_Ehdr ehdr;
799 GElf_Shdr shdr;
800 GElf_Shdr tshdr;
801 Elf_Data *syms, *opddata = NULL;
802 GElf_Sym sym;
803 Elf_Scn *sec, *sec_strndx;
804 Elf *elf;
805 int nr = 0;
806 bool remap_kernel = false, adjust_kernel_syms = false;
807
808 if (kmap && !kmaps)
809 return -1;
810
811 dso->symtab_type = syms_ss->type;
812 dso->is_64_bit = syms_ss->is_64_bit;
813 dso->rel = syms_ss->ehdr.e_type == ET_REL;
814
815 /*
816 * Modules may already have symbols from kallsyms, but those symbols
817 * have the wrong values for the dso maps, so remove them.
818 */
819 if (kmodule && syms_ss->symtab)
820 symbols__delete(&dso->symbols[map->type]);
821
822 if (!syms_ss->symtab) {
823 /*
824 * If the vmlinux is stripped, fail so we will fall back
825 * to using kallsyms. The vmlinux runtime symbols aren't
826 * of much use.
827 */
828 if (dso->kernel)
829 goto out_elf_end;
830
831 syms_ss->symtab = syms_ss->dynsym;
832 syms_ss->symshdr = syms_ss->dynshdr;
833 }
834
835 elf = syms_ss->elf;
836 ehdr = syms_ss->ehdr;
837 sec = syms_ss->symtab;
838 shdr = syms_ss->symshdr;
839
840 if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
841 ".text", NULL))
842 dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
843
844 if (runtime_ss->opdsec)
845 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
846
847 syms = elf_getdata(sec, NULL);
848 if (syms == NULL)
849 goto out_elf_end;
850
851 sec = elf_getscn(elf, shdr.sh_link);
852 if (sec == NULL)
853 goto out_elf_end;
854
855 symstrs = elf_getdata(sec, NULL);
856 if (symstrs == NULL)
857 goto out_elf_end;
858
859 sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
860 if (sec_strndx == NULL)
861 goto out_elf_end;
862
863 secstrs = elf_getdata(sec_strndx, NULL);
864 if (secstrs == NULL)
865 goto out_elf_end;
866
867 nr_syms = shdr.sh_size / shdr.sh_entsize;
868
869 memset(&sym, 0, sizeof(sym));
870
871 /*
872 * The kernel relocation symbol is needed in advance in order to adjust
873 * kernel maps correctly.
874 */
875 if (ref_reloc_sym_not_found(kmap)) {
876 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
877 const char *elf_name = elf_sym__name(&sym, symstrs);
878
879 if (strcmp(elf_name, kmap->ref_reloc_sym->name))
880 continue;
881 kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
882 map->reloc = kmap->ref_reloc_sym->addr -
883 kmap->ref_reloc_sym->unrelocated_addr;
884 break;
885 }
886 }
887
888 /*
889 * Handle any relocation of vdso necessary because older kernels
890 * attempted to prelink vdso to its virtual address.
891 */
892 if (dso__is_vdso(dso))
893 map->reloc = map->start - dso->text_offset;
894
895 dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
896 /*
897 * Initial kernel and module mappings do not map to the dso. For
898 * function mappings, flag the fixups.
899 */
900 if (map->type == MAP__FUNCTION && (dso->kernel || kmodule)) {
901 remap_kernel = true;
902 adjust_kernel_syms = dso->adjust_symbols;
903 }
904 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
905 struct symbol *f;
906 const char *elf_name = elf_sym__name(&sym, symstrs);
907 char *demangled = NULL;
908 int is_label = elf_sym__is_label(&sym);
909 const char *section_name;
910 bool used_opd = false;
911
912 if (!is_label && !elf_sym__is_a(&sym, map->type))
913 continue;
914
915 /* Reject ARM ELF "mapping symbols": these aren't unique and
916 * don't identify functions, so will confuse the profile
917 * output: */
918 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
919 if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
920 && (elf_name[2] == '\0' || elf_name[2] == '.'))
921 continue;
922 }
923
924 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
925 u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
926 u64 *opd = opddata->d_buf + offset;
927 sym.st_value = DSO__SWAP(dso, u64, *opd);
928 sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
929 sym.st_value);
930 used_opd = true;
931 }
932 /*
933 * When loading symbols in a data mapping, ABS symbols (which
934 * has a value of SHN_ABS in its st_shndx) failed at
935 * elf_getscn(). And it marks the loading as a failure so
936 * already loaded symbols cannot be fixed up.
937 *
938 * I'm not sure what should be done. Just ignore them for now.
939 * - Namhyung Kim
940 */
941 if (sym.st_shndx == SHN_ABS)
942 continue;
943
944 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
945 if (!sec)
946 goto out_elf_end;
947
948 gelf_getshdr(sec, &shdr);
949
950 if (is_label && !elf_sec__is_a(&shdr, secstrs, map->type))
951 continue;
952
953 section_name = elf_sec__name(&shdr, secstrs);
954
955 /* On ARM, symbols for thumb functions have 1 added to
956 * the symbol address as a flag - remove it */
957 if ((ehdr.e_machine == EM_ARM) &&
958 (map->type == MAP__FUNCTION) &&
959 (sym.st_value & 1))
960 --sym.st_value;
961
962 if (dso->kernel || kmodule) {
963 char dso_name[PATH_MAX];
964
965 /* Adjust symbol to map to file offset */
966 if (adjust_kernel_syms)
967 sym.st_value -= shdr.sh_addr - shdr.sh_offset;
968
969 if (strcmp(section_name,
970 (curr_dso->short_name +
971 dso->short_name_len)) == 0)
972 goto new_symbol;
973
974 if (strcmp(section_name, ".text") == 0) {
975 /*
976 * The initial kernel mapping is based on
977 * kallsyms and identity maps. Overwrite it to
978 * map to the kernel dso.
979 */
980 if (remap_kernel && dso->kernel) {
981 remap_kernel = false;
982 map->start = shdr.sh_addr +
983 ref_reloc(kmap);
984 map->end = map->start + shdr.sh_size;
985 map->pgoff = shdr.sh_offset;
986 map->map_ip = map__map_ip;
987 map->unmap_ip = map__unmap_ip;
988 /* Ensure maps are correctly ordered */
989 if (kmaps) {
990 map__get(map);
991 map_groups__remove(kmaps, map);
992 map_groups__insert(kmaps, map);
993 map__put(map);
994 }
995 }
996
997 /*
998 * The initial module mapping is based on
999 * /proc/modules mapped to offset zero.
1000 * Overwrite it to map to the module dso.
1001 */
1002 if (remap_kernel && kmodule) {
1003 remap_kernel = false;
1004 map->pgoff = shdr.sh_offset;
1005 }
1006
1007 curr_map = map;
1008 curr_dso = dso;
1009 goto new_symbol;
1010 }
1011
1012 if (!kmap)
1013 goto new_symbol;
1014
1015 snprintf(dso_name, sizeof(dso_name),
1016 "%s%s", dso->short_name, section_name);
1017
1018 curr_map = map_groups__find_by_name(kmaps, map->type, dso_name);
1019 if (curr_map == NULL) {
1020 u64 start = sym.st_value;
1021
1022 if (kmodule)
1023 start += map->start + shdr.sh_offset;
1024
1025 curr_dso = dso__new(dso_name);
1026 if (curr_dso == NULL)
1027 goto out_elf_end;
1028 curr_dso->kernel = dso->kernel;
1029 curr_dso->long_name = dso->long_name;
1030 curr_dso->long_name_len = dso->long_name_len;
1031 curr_map = map__new2(start, curr_dso,
1032 map->type);
1033 dso__put(curr_dso);
1034 if (curr_map == NULL) {
1035 goto out_elf_end;
1036 }
1037 if (adjust_kernel_syms) {
1038 curr_map->start = shdr.sh_addr +
1039 ref_reloc(kmap);
1040 curr_map->end = curr_map->start +
1041 shdr.sh_size;
1042 curr_map->pgoff = shdr.sh_offset;
1043 } else {
1044 curr_map->map_ip = identity__map_ip;
1045 curr_map->unmap_ip = identity__map_ip;
1046 }
1047 curr_dso->symtab_type = dso->symtab_type;
1048 map_groups__insert(kmaps, curr_map);
1049 /*
1050 * Add it before we drop the referece to curr_map,
1051 * i.e. while we still are sure to have a reference
1052 * to this DSO via curr_map->dso.
1053 */
1054 dsos__add(&map->groups->machine->dsos, curr_dso);
1055 /* kmaps already got it */
1056 map__put(curr_map);
1057 dso__set_loaded(curr_dso, map->type);
1058 } else
1059 curr_dso = curr_map->dso;
1060
1061 goto new_symbol;
1062 }
1063
1064 if ((used_opd && runtime_ss->adjust_symbols)
1065 || (!used_opd && syms_ss->adjust_symbols)) {
1066 pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1067 "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
1068 (u64)sym.st_value, (u64)shdr.sh_addr,
1069 (u64)shdr.sh_offset);
1070 sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1071 }
1072 new_symbol:
1073 /*
1074 * We need to figure out if the object was created from C++ sources
1075 * DWARF DW_compile_unit has this, but we don't always have access
1076 * to it...
1077 */
1078 if (want_demangle(dso->kernel || kmodule)) {
1079 int demangle_flags = DMGL_NO_OPTS;
1080 if (verbose)
1081 demangle_flags = DMGL_PARAMS | DMGL_ANSI;
1082
1083 demangled = bfd_demangle(NULL, elf_name, demangle_flags);
1084 if (demangled == NULL)
1085 demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
1086 else if (rust_is_mangled(demangled))
1087 /*
1088 * Input to Rust demangling is the BFD-demangled
1089 * name which it Rust-demangles in place.
1090 */
1091 rust_demangle_sym(demangled);
1092
1093 if (demangled != NULL)
1094 elf_name = demangled;
1095 }
1096 f = symbol__new(sym.st_value, sym.st_size,
1097 GELF_ST_BIND(sym.st_info), elf_name);
1098 free(demangled);
1099 if (!f)
1100 goto out_elf_end;
1101
1102 arch__sym_update(f, &sym);
1103
1104 if (filter && filter(curr_map, f))
1105 symbol__delete(f);
1106 else {
1107 symbols__insert(&curr_dso->symbols[curr_map->type], f);
1108 nr++;
1109 }
1110 }
1111
1112 /*
1113 * For misannotated, zeroed, ASM function sizes.
1114 */
1115 if (nr > 0) {
1116 if (!symbol_conf.allow_aliases)
1117 symbols__fixup_duplicate(&dso->symbols[map->type]);
1118 symbols__fixup_end(&dso->symbols[map->type]);
1119 if (kmap) {
1120 /*
1121 * We need to fixup this here too because we create new
1122 * maps here, for things like vsyscall sections.
1123 */
1124 __map_groups__fixup_end(kmaps, map->type);
1125 }
1126 }
1127 err = nr;
1128 out_elf_end:
1129 return err;
1130 }
1131
1132 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1133 {
1134 GElf_Phdr phdr;
1135 size_t i, phdrnum;
1136 int err;
1137 u64 sz;
1138
1139 if (elf_getphdrnum(elf, &phdrnum))
1140 return -1;
1141
1142 for (i = 0; i < phdrnum; i++) {
1143 if (gelf_getphdr(elf, i, &phdr) == NULL)
1144 return -1;
1145 if (phdr.p_type != PT_LOAD)
1146 continue;
1147 if (exe) {
1148 if (!(phdr.p_flags & PF_X))
1149 continue;
1150 } else {
1151 if (!(phdr.p_flags & PF_R))
1152 continue;
1153 }
1154 sz = min(phdr.p_memsz, phdr.p_filesz);
1155 if (!sz)
1156 continue;
1157 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1158 if (err)
1159 return err;
1160 }
1161 return 0;
1162 }
1163
1164 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1165 bool *is_64_bit)
1166 {
1167 int err;
1168 Elf *elf;
1169
1170 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1171 if (elf == NULL)
1172 return -1;
1173
1174 if (is_64_bit)
1175 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1176
1177 err = elf_read_maps(elf, exe, mapfn, data);
1178
1179 elf_end(elf);
1180 return err;
1181 }
1182
1183 enum dso_type dso__type_fd(int fd)
1184 {
1185 enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1186 GElf_Ehdr ehdr;
1187 Elf_Kind ek;
1188 Elf *elf;
1189
1190 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1191 if (elf == NULL)
1192 goto out;
1193
1194 ek = elf_kind(elf);
1195 if (ek != ELF_K_ELF)
1196 goto out_end;
1197
1198 if (gelf_getclass(elf) == ELFCLASS64) {
1199 dso_type = DSO__TYPE_64BIT;
1200 goto out_end;
1201 }
1202
1203 if (gelf_getehdr(elf, &ehdr) == NULL)
1204 goto out_end;
1205
1206 if (ehdr.e_machine == EM_X86_64)
1207 dso_type = DSO__TYPE_X32BIT;
1208 else
1209 dso_type = DSO__TYPE_32BIT;
1210 out_end:
1211 elf_end(elf);
1212 out:
1213 return dso_type;
1214 }
1215
1216 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1217 {
1218 ssize_t r;
1219 size_t n;
1220 int err = -1;
1221 char *buf = malloc(page_size);
1222
1223 if (buf == NULL)
1224 return -1;
1225
1226 if (lseek(to, to_offs, SEEK_SET) != to_offs)
1227 goto out;
1228
1229 if (lseek(from, from_offs, SEEK_SET) != from_offs)
1230 goto out;
1231
1232 while (len) {
1233 n = page_size;
1234 if (len < n)
1235 n = len;
1236 /* Use read because mmap won't work on proc files */
1237 r = read(from, buf, n);
1238 if (r < 0)
1239 goto out;
1240 if (!r)
1241 break;
1242 n = r;
1243 r = write(to, buf, n);
1244 if (r < 0)
1245 goto out;
1246 if ((size_t)r != n)
1247 goto out;
1248 len -= n;
1249 }
1250
1251 err = 0;
1252 out:
1253 free(buf);
1254 return err;
1255 }
1256
1257 struct kcore {
1258 int fd;
1259 int elfclass;
1260 Elf *elf;
1261 GElf_Ehdr ehdr;
1262 };
1263
1264 static int kcore__open(struct kcore *kcore, const char *filename)
1265 {
1266 GElf_Ehdr *ehdr;
1267
1268 kcore->fd = open(filename, O_RDONLY);
1269 if (kcore->fd == -1)
1270 return -1;
1271
1272 kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1273 if (!kcore->elf)
1274 goto out_close;
1275
1276 kcore->elfclass = gelf_getclass(kcore->elf);
1277 if (kcore->elfclass == ELFCLASSNONE)
1278 goto out_end;
1279
1280 ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1281 if (!ehdr)
1282 goto out_end;
1283
1284 return 0;
1285
1286 out_end:
1287 elf_end(kcore->elf);
1288 out_close:
1289 close(kcore->fd);
1290 return -1;
1291 }
1292
1293 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1294 bool temp)
1295 {
1296 kcore->elfclass = elfclass;
1297
1298 if (temp)
1299 kcore->fd = mkstemp(filename);
1300 else
1301 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1302 if (kcore->fd == -1)
1303 return -1;
1304
1305 kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1306 if (!kcore->elf)
1307 goto out_close;
1308
1309 if (!gelf_newehdr(kcore->elf, elfclass))
1310 goto out_end;
1311
1312 memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
1313
1314 return 0;
1315
1316 out_end:
1317 elf_end(kcore->elf);
1318 out_close:
1319 close(kcore->fd);
1320 unlink(filename);
1321 return -1;
1322 }
1323
1324 static void kcore__close(struct kcore *kcore)
1325 {
1326 elf_end(kcore->elf);
1327 close(kcore->fd);
1328 }
1329
1330 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1331 {
1332 GElf_Ehdr *ehdr = &to->ehdr;
1333 GElf_Ehdr *kehdr = &from->ehdr;
1334
1335 memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1336 ehdr->e_type = kehdr->e_type;
1337 ehdr->e_machine = kehdr->e_machine;
1338 ehdr->e_version = kehdr->e_version;
1339 ehdr->e_entry = 0;
1340 ehdr->e_shoff = 0;
1341 ehdr->e_flags = kehdr->e_flags;
1342 ehdr->e_phnum = count;
1343 ehdr->e_shentsize = 0;
1344 ehdr->e_shnum = 0;
1345 ehdr->e_shstrndx = 0;
1346
1347 if (from->elfclass == ELFCLASS32) {
1348 ehdr->e_phoff = sizeof(Elf32_Ehdr);
1349 ehdr->e_ehsize = sizeof(Elf32_Ehdr);
1350 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1351 } else {
1352 ehdr->e_phoff = sizeof(Elf64_Ehdr);
1353 ehdr->e_ehsize = sizeof(Elf64_Ehdr);
1354 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1355 }
1356
1357 if (!gelf_update_ehdr(to->elf, ehdr))
1358 return -1;
1359
1360 if (!gelf_newphdr(to->elf, count))
1361 return -1;
1362
1363 return 0;
1364 }
1365
1366 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1367 u64 addr, u64 len)
1368 {
1369 GElf_Phdr phdr = {
1370 .p_type = PT_LOAD,
1371 .p_flags = PF_R | PF_W | PF_X,
1372 .p_offset = offset,
1373 .p_vaddr = addr,
1374 .p_paddr = 0,
1375 .p_filesz = len,
1376 .p_memsz = len,
1377 .p_align = page_size,
1378 };
1379
1380 if (!gelf_update_phdr(kcore->elf, idx, &phdr))
1381 return -1;
1382
1383 return 0;
1384 }
1385
1386 static off_t kcore__write(struct kcore *kcore)
1387 {
1388 return elf_update(kcore->elf, ELF_C_WRITE);
1389 }
1390
1391 struct phdr_data {
1392 off_t offset;
1393 u64 addr;
1394 u64 len;
1395 };
1396
1397 struct kcore_copy_info {
1398 u64 stext;
1399 u64 etext;
1400 u64 first_symbol;
1401 u64 last_symbol;
1402 u64 first_module;
1403 u64 last_module_symbol;
1404 struct phdr_data kernel_map;
1405 struct phdr_data modules_map;
1406 };
1407
1408 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1409 u64 start)
1410 {
1411 struct kcore_copy_info *kci = arg;
1412
1413 if (!symbol_type__is_a(type, MAP__FUNCTION))
1414 return 0;
1415
1416 if (strchr(name, '[')) {
1417 if (start > kci->last_module_symbol)
1418 kci->last_module_symbol = start;
1419 return 0;
1420 }
1421
1422 if (!kci->first_symbol || start < kci->first_symbol)
1423 kci->first_symbol = start;
1424
1425 if (!kci->last_symbol || start > kci->last_symbol)
1426 kci->last_symbol = start;
1427
1428 if (!strcmp(name, "_stext")) {
1429 kci->stext = start;
1430 return 0;
1431 }
1432
1433 if (!strcmp(name, "_etext")) {
1434 kci->etext = start;
1435 return 0;
1436 }
1437
1438 return 0;
1439 }
1440
1441 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1442 const char *dir)
1443 {
1444 char kallsyms_filename[PATH_MAX];
1445
1446 scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1447
1448 if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1449 return -1;
1450
1451 if (kallsyms__parse(kallsyms_filename, kci,
1452 kcore_copy__process_kallsyms) < 0)
1453 return -1;
1454
1455 return 0;
1456 }
1457
1458 static int kcore_copy__process_modules(void *arg,
1459 const char *name __maybe_unused,
1460 u64 start)
1461 {
1462 struct kcore_copy_info *kci = arg;
1463
1464 if (!kci->first_module || start < kci->first_module)
1465 kci->first_module = start;
1466
1467 return 0;
1468 }
1469
1470 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1471 const char *dir)
1472 {
1473 char modules_filename[PATH_MAX];
1474
1475 scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1476
1477 if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1478 return -1;
1479
1480 if (modules__parse(modules_filename, kci,
1481 kcore_copy__process_modules) < 0)
1482 return -1;
1483
1484 return 0;
1485 }
1486
1487 static void kcore_copy__map(struct phdr_data *p, u64 start, u64 end, u64 pgoff,
1488 u64 s, u64 e)
1489 {
1490 if (p->addr || s < start || s >= end)
1491 return;
1492
1493 p->addr = s;
1494 p->offset = (s - start) + pgoff;
1495 p->len = e < end ? e - s : end - s;
1496 }
1497
1498 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1499 {
1500 struct kcore_copy_info *kci = data;
1501 u64 end = start + len;
1502
1503 kcore_copy__map(&kci->kernel_map, start, end, pgoff, kci->stext,
1504 kci->etext);
1505
1506 kcore_copy__map(&kci->modules_map, start, end, pgoff, kci->first_module,
1507 kci->last_module_symbol);
1508
1509 return 0;
1510 }
1511
1512 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1513 {
1514 if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1515 return -1;
1516
1517 return 0;
1518 }
1519
1520 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1521 Elf *elf)
1522 {
1523 if (kcore_copy__parse_kallsyms(kci, dir))
1524 return -1;
1525
1526 if (kcore_copy__parse_modules(kci, dir))
1527 return -1;
1528
1529 if (kci->stext)
1530 kci->stext = round_down(kci->stext, page_size);
1531 else
1532 kci->stext = round_down(kci->first_symbol, page_size);
1533
1534 if (kci->etext) {
1535 kci->etext = round_up(kci->etext, page_size);
1536 } else if (kci->last_symbol) {
1537 kci->etext = round_up(kci->last_symbol, page_size);
1538 kci->etext += page_size;
1539 }
1540
1541 kci->first_module = round_down(kci->first_module, page_size);
1542
1543 if (kci->last_module_symbol) {
1544 kci->last_module_symbol = round_up(kci->last_module_symbol,
1545 page_size);
1546 kci->last_module_symbol += page_size;
1547 }
1548
1549 if (!kci->stext || !kci->etext)
1550 return -1;
1551
1552 if (kci->first_module && !kci->last_module_symbol)
1553 return -1;
1554
1555 return kcore_copy__read_maps(kci, elf);
1556 }
1557
1558 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1559 const char *name)
1560 {
1561 char from_filename[PATH_MAX];
1562 char to_filename[PATH_MAX];
1563
1564 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1565 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1566
1567 return copyfile_mode(from_filename, to_filename, 0400);
1568 }
1569
1570 static int kcore_copy__unlink(const char *dir, const char *name)
1571 {
1572 char filename[PATH_MAX];
1573
1574 scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1575
1576 return unlink(filename);
1577 }
1578
1579 static int kcore_copy__compare_fds(int from, int to)
1580 {
1581 char *buf_from;
1582 char *buf_to;
1583 ssize_t ret;
1584 size_t len;
1585 int err = -1;
1586
1587 buf_from = malloc(page_size);
1588 buf_to = malloc(page_size);
1589 if (!buf_from || !buf_to)
1590 goto out;
1591
1592 while (1) {
1593 /* Use read because mmap won't work on proc files */
1594 ret = read(from, buf_from, page_size);
1595 if (ret < 0)
1596 goto out;
1597
1598 if (!ret)
1599 break;
1600
1601 len = ret;
1602
1603 if (readn(to, buf_to, len) != (int)len)
1604 goto out;
1605
1606 if (memcmp(buf_from, buf_to, len))
1607 goto out;
1608 }
1609
1610 err = 0;
1611 out:
1612 free(buf_to);
1613 free(buf_from);
1614 return err;
1615 }
1616
1617 static int kcore_copy__compare_files(const char *from_filename,
1618 const char *to_filename)
1619 {
1620 int from, to, err = -1;
1621
1622 from = open(from_filename, O_RDONLY);
1623 if (from < 0)
1624 return -1;
1625
1626 to = open(to_filename, O_RDONLY);
1627 if (to < 0)
1628 goto out_close_from;
1629
1630 err = kcore_copy__compare_fds(from, to);
1631
1632 close(to);
1633 out_close_from:
1634 close(from);
1635 return err;
1636 }
1637
1638 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
1639 const char *name)
1640 {
1641 char from_filename[PATH_MAX];
1642 char to_filename[PATH_MAX];
1643
1644 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1645 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1646
1647 return kcore_copy__compare_files(from_filename, to_filename);
1648 }
1649
1650 /**
1651 * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1652 * @from_dir: from directory
1653 * @to_dir: to directory
1654 *
1655 * This function copies kallsyms, modules and kcore files from one directory to
1656 * another. kallsyms and modules are copied entirely. Only code segments are
1657 * copied from kcore. It is assumed that two segments suffice: one for the
1658 * kernel proper and one for all the modules. The code segments are determined
1659 * from kallsyms and modules files. The kernel map starts at _stext or the
1660 * lowest function symbol, and ends at _etext or the highest function symbol.
1661 * The module map starts at the lowest module address and ends at the highest
1662 * module symbol. Start addresses are rounded down to the nearest page. End
1663 * addresses are rounded up to the nearest page. An extra page is added to the
1664 * highest kernel symbol and highest module symbol to, hopefully, encompass that
1665 * symbol too. Because it contains only code sections, the resulting kcore is
1666 * unusual. One significant peculiarity is that the mapping (start -> pgoff)
1667 * is not the same for the kernel map and the modules map. That happens because
1668 * the data is copied adjacently whereas the original kcore has gaps. Finally,
1669 * kallsyms and modules files are compared with their copies to check that
1670 * modules have not been loaded or unloaded while the copies were taking place.
1671 *
1672 * Return: %0 on success, %-1 on failure.
1673 */
1674 int kcore_copy(const char *from_dir, const char *to_dir)
1675 {
1676 struct kcore kcore;
1677 struct kcore extract;
1678 size_t count = 2;
1679 int idx = 0, err = -1;
1680 off_t offset = page_size, sz, modules_offset = 0;
1681 struct kcore_copy_info kci = { .stext = 0, };
1682 char kcore_filename[PATH_MAX];
1683 char extract_filename[PATH_MAX];
1684
1685 if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
1686 return -1;
1687
1688 if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
1689 goto out_unlink_kallsyms;
1690
1691 scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
1692 scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
1693
1694 if (kcore__open(&kcore, kcore_filename))
1695 goto out_unlink_modules;
1696
1697 if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
1698 goto out_kcore_close;
1699
1700 if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
1701 goto out_kcore_close;
1702
1703 if (!kci.modules_map.addr)
1704 count -= 1;
1705
1706 if (kcore__copy_hdr(&kcore, &extract, count))
1707 goto out_extract_close;
1708
1709 if (kcore__add_phdr(&extract, idx++, offset, kci.kernel_map.addr,
1710 kci.kernel_map.len))
1711 goto out_extract_close;
1712
1713 if (kci.modules_map.addr) {
1714 modules_offset = offset + kci.kernel_map.len;
1715 if (kcore__add_phdr(&extract, idx, modules_offset,
1716 kci.modules_map.addr, kci.modules_map.len))
1717 goto out_extract_close;
1718 }
1719
1720 sz = kcore__write(&extract);
1721 if (sz < 0 || sz > offset)
1722 goto out_extract_close;
1723
1724 if (copy_bytes(kcore.fd, kci.kernel_map.offset, extract.fd, offset,
1725 kci.kernel_map.len))
1726 goto out_extract_close;
1727
1728 if (modules_offset && copy_bytes(kcore.fd, kci.modules_map.offset,
1729 extract.fd, modules_offset,
1730 kci.modules_map.len))
1731 goto out_extract_close;
1732
1733 if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
1734 goto out_extract_close;
1735
1736 if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
1737 goto out_extract_close;
1738
1739 err = 0;
1740
1741 out_extract_close:
1742 kcore__close(&extract);
1743 if (err)
1744 unlink(extract_filename);
1745 out_kcore_close:
1746 kcore__close(&kcore);
1747 out_unlink_modules:
1748 if (err)
1749 kcore_copy__unlink(to_dir, "modules");
1750 out_unlink_kallsyms:
1751 if (err)
1752 kcore_copy__unlink(to_dir, "kallsyms");
1753
1754 return err;
1755 }
1756
1757 int kcore_extract__create(struct kcore_extract *kce)
1758 {
1759 struct kcore kcore;
1760 struct kcore extract;
1761 size_t count = 1;
1762 int idx = 0, err = -1;
1763 off_t offset = page_size, sz;
1764
1765 if (kcore__open(&kcore, kce->kcore_filename))
1766 return -1;
1767
1768 strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
1769 if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
1770 goto out_kcore_close;
1771
1772 if (kcore__copy_hdr(&kcore, &extract, count))
1773 goto out_extract_close;
1774
1775 if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
1776 goto out_extract_close;
1777
1778 sz = kcore__write(&extract);
1779 if (sz < 0 || sz > offset)
1780 goto out_extract_close;
1781
1782 if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
1783 goto out_extract_close;
1784
1785 err = 0;
1786
1787 out_extract_close:
1788 kcore__close(&extract);
1789 if (err)
1790 unlink(kce->extract_filename);
1791 out_kcore_close:
1792 kcore__close(&kcore);
1793
1794 return err;
1795 }
1796
1797 void kcore_extract__delete(struct kcore_extract *kce)
1798 {
1799 unlink(kce->extract_filename);
1800 }
1801
1802 #ifdef HAVE_GELF_GETNOTE_SUPPORT
1803 /**
1804 * populate_sdt_note : Parse raw data and identify SDT note
1805 * @elf: elf of the opened file
1806 * @data: raw data of a section with description offset applied
1807 * @len: note description size
1808 * @type: type of the note
1809 * @sdt_notes: List to add the SDT note
1810 *
1811 * Responsible for parsing the @data in section .note.stapsdt in @elf and
1812 * if its an SDT note, it appends to @sdt_notes list.
1813 */
1814 static int populate_sdt_note(Elf **elf, const char *data, size_t len,
1815 struct list_head *sdt_notes)
1816 {
1817 const char *provider, *name;
1818 struct sdt_note *tmp = NULL;
1819 GElf_Ehdr ehdr;
1820 GElf_Addr base_off = 0;
1821 GElf_Shdr shdr;
1822 int ret = -EINVAL;
1823
1824 union {
1825 Elf64_Addr a64[NR_ADDR];
1826 Elf32_Addr a32[NR_ADDR];
1827 } buf;
1828
1829 Elf_Data dst = {
1830 .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
1831 .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),
1832 .d_off = 0, .d_align = 0
1833 };
1834 Elf_Data src = {
1835 .d_buf = (void *) data, .d_type = ELF_T_ADDR,
1836 .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
1837 .d_align = 0
1838 };
1839
1840 tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
1841 if (!tmp) {
1842 ret = -ENOMEM;
1843 goto out_err;
1844 }
1845
1846 INIT_LIST_HEAD(&tmp->note_list);
1847
1848 if (len < dst.d_size + 3)
1849 goto out_free_note;
1850
1851 /* Translation from file representation to memory representation */
1852 if (gelf_xlatetom(*elf, &dst, &src,
1853 elf_getident(*elf, NULL)[EI_DATA]) == NULL) {
1854 pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
1855 goto out_free_note;
1856 }
1857
1858 /* Populate the fields of sdt_note */
1859 provider = data + dst.d_size;
1860
1861 name = (const char *)memchr(provider, '\0', data + len - provider);
1862 if (name++ == NULL)
1863 goto out_free_note;
1864
1865 tmp->provider = strdup(provider);
1866 if (!tmp->provider) {
1867 ret = -ENOMEM;
1868 goto out_free_note;
1869 }
1870 tmp->name = strdup(name);
1871 if (!tmp->name) {
1872 ret = -ENOMEM;
1873 goto out_free_prov;
1874 }
1875
1876 if (gelf_getclass(*elf) == ELFCLASS32) {
1877 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
1878 tmp->bit32 = true;
1879 } else {
1880 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
1881 tmp->bit32 = false;
1882 }
1883
1884 if (!gelf_getehdr(*elf, &ehdr)) {
1885 pr_debug("%s : cannot get elf header.\n", __func__);
1886 ret = -EBADF;
1887 goto out_free_name;
1888 }
1889
1890 /* Adjust the prelink effect :
1891 * Find out the .stapsdt.base section.
1892 * This scn will help us to handle prelinking (if present).
1893 * Compare the retrieved file offset of the base section with the
1894 * base address in the description of the SDT note. If its different,
1895 * then accordingly, adjust the note location.
1896 */
1897 if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL)) {
1898 base_off = shdr.sh_offset;
1899 if (base_off) {
1900 if (tmp->bit32)
1901 tmp->addr.a32[0] = tmp->addr.a32[0] + base_off -
1902 tmp->addr.a32[1];
1903 else
1904 tmp->addr.a64[0] = tmp->addr.a64[0] + base_off -
1905 tmp->addr.a64[1];
1906 }
1907 }
1908
1909 list_add_tail(&tmp->note_list, sdt_notes);
1910 return 0;
1911
1912 out_free_name:
1913 free(tmp->name);
1914 out_free_prov:
1915 free(tmp->provider);
1916 out_free_note:
1917 free(tmp);
1918 out_err:
1919 return ret;
1920 }
1921
1922 /**
1923 * construct_sdt_notes_list : constructs a list of SDT notes
1924 * @elf : elf to look into
1925 * @sdt_notes : empty list_head
1926 *
1927 * Scans the sections in 'elf' for the section
1928 * .note.stapsdt. It, then calls populate_sdt_note to find
1929 * out the SDT events and populates the 'sdt_notes'.
1930 */
1931 static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
1932 {
1933 GElf_Ehdr ehdr;
1934 Elf_Scn *scn = NULL;
1935 Elf_Data *data;
1936 GElf_Shdr shdr;
1937 size_t shstrndx, next;
1938 GElf_Nhdr nhdr;
1939 size_t name_off, desc_off, offset;
1940 int ret = 0;
1941
1942 if (gelf_getehdr(elf, &ehdr) == NULL) {
1943 ret = -EBADF;
1944 goto out_ret;
1945 }
1946 if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
1947 ret = -EBADF;
1948 goto out_ret;
1949 }
1950
1951 /* Look for the required section */
1952 scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
1953 if (!scn) {
1954 ret = -ENOENT;
1955 goto out_ret;
1956 }
1957
1958 if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
1959 ret = -ENOENT;
1960 goto out_ret;
1961 }
1962
1963 data = elf_getdata(scn, NULL);
1964
1965 /* Get the SDT notes */
1966 for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
1967 &desc_off)) > 0; offset = next) {
1968 if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
1969 !memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
1970 sizeof(SDT_NOTE_NAME))) {
1971 /* Check the type of the note */
1972 if (nhdr.n_type != SDT_NOTE_TYPE)
1973 goto out_ret;
1974
1975 ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
1976 nhdr.n_descsz, sdt_notes);
1977 if (ret < 0)
1978 goto out_ret;
1979 }
1980 }
1981 if (list_empty(sdt_notes))
1982 ret = -ENOENT;
1983
1984 out_ret:
1985 return ret;
1986 }
1987
1988 /**
1989 * get_sdt_note_list : Wrapper to construct a list of sdt notes
1990 * @head : empty list_head
1991 * @target : file to find SDT notes from
1992 *
1993 * This opens the file, initializes
1994 * the ELF and then calls construct_sdt_notes_list.
1995 */
1996 int get_sdt_note_list(struct list_head *head, const char *target)
1997 {
1998 Elf *elf;
1999 int fd, ret;
2000
2001 fd = open(target, O_RDONLY);
2002 if (fd < 0)
2003 return -EBADF;
2004
2005 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
2006 if (!elf) {
2007 ret = -EBADF;
2008 goto out_close;
2009 }
2010 ret = construct_sdt_notes_list(elf, head);
2011 elf_end(elf);
2012 out_close:
2013 close(fd);
2014 return ret;
2015 }
2016
2017 /**
2018 * cleanup_sdt_note_list : free the sdt notes' list
2019 * @sdt_notes: sdt notes' list
2020 *
2021 * Free up the SDT notes in @sdt_notes.
2022 * Returns the number of SDT notes free'd.
2023 */
2024 int cleanup_sdt_note_list(struct list_head *sdt_notes)
2025 {
2026 struct sdt_note *tmp, *pos;
2027 int nr_free = 0;
2028
2029 list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
2030 list_del(&pos->note_list);
2031 free(pos->name);
2032 free(pos->provider);
2033 free(pos);
2034 nr_free++;
2035 }
2036 return nr_free;
2037 }
2038
2039 /**
2040 * sdt_notes__get_count: Counts the number of sdt events
2041 * @start: list_head to sdt_notes list
2042 *
2043 * Returns the number of SDT notes in a list
2044 */
2045 int sdt_notes__get_count(struct list_head *start)
2046 {
2047 struct sdt_note *sdt_ptr;
2048 int count = 0;
2049
2050 list_for_each_entry(sdt_ptr, start, note_list)
2051 count++;
2052 return count;
2053 }
2054 #endif
2055
2056 void symbol__elf_init(void)
2057 {
2058 elf_version(EV_CURRENT);
2059 }
Linux kernel - Deliverables
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