tools/perf/util/symbol-elf.c

   1 #include <libelf.h>
   2 #include <gelf.h>
   3 #include <elf.h>
   4 #include <fcntl.h>
   5 #include <stdio.h>
   6 #include <errno.h>
   7 #include <string.h>
   8 #include <unistd.h>
   9 #include <inttypes.h>
  10
  11 #include "symbol.h"
  12 #include "debug.h"
  13
  14 #ifndef NT_GNU_BUILD_ID
  15 #define NT_GNU_BUILD_ID 3
  16 #endif
  17
  18 /**
  19  * elf_symtab__for_each_symbol - iterate thru all the symbols
  20  *
  21  * @syms: struct elf_symtab instance to iterate
  22  * @idx: uint32_t idx
  23  * @sym: GElf_Sym iterator
  24  */
  25 #define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
  26         for (idx = 0, gelf_getsym(syms, idx, &sym);\
  27              idx < nr_syms; \
  28              idx++, gelf_getsym(syms, idx, &sym))
  29
  30 static inline uint8_t elf_sym__type(const GElf_Sym *sym)
  31 {
  32         return GELF_ST_TYPE(sym->st_info);
  33 }
  34
  35 static inline int elf_sym__is_function(const GElf_Sym *sym)
  36 {
  37         return elf_sym__type(sym) == STT_FUNC &&
  38                sym->st_name != 0 &&
  39                sym->st_shndx != SHN_UNDEF;
  40 }
  41
  42 static inline bool elf_sym__is_object(const GElf_Sym *sym)
  43 {
  44         return elf_sym__type(sym) == STT_OBJECT &&
  45                 sym->st_name != 0 &&
  46                 sym->st_shndx != SHN_UNDEF;
  47 }
  48
  49 static inline int elf_sym__is_label(const GElf_Sym *sym)
  50 {
  51         return elf_sym__type(sym) == STT_NOTYPE &&
  52                 sym->st_name != 0 &&
  53                 sym->st_shndx != SHN_UNDEF &&
  54                 sym->st_shndx != SHN_ABS;
  55 }
  56
  57 static bool elf_sym__is_a(GElf_Sym *sym, enum map_type type)
  58 {
  59         switch (type) {
  60         case MAP__FUNCTION:
  61                 return elf_sym__is_function(sym);
  62         case MAP__VARIABLE:
  63                 return elf_sym__is_object(sym);
  64         default:
  65                 return false;
  66         }
  67 }
  68
  69 static inline const char *elf_sym__name(const GElf_Sym *sym,
  70                                         const Elf_Data *symstrs)
  71 {
  72         return symstrs->d_buf + sym->st_name;
  73 }
  74
  75 static inline const char *elf_sec__name(const GElf_Shdr *shdr,
  76                                         const Elf_Data *secstrs)
  77 {
  78         return secstrs->d_buf + shdr->sh_name;
  79 }
  80
  81 static inline int elf_sec__is_text(const GElf_Shdr *shdr,
  82                                         const Elf_Data *secstrs)
  83 {
  84         return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
  85 }
  86
  87 static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
  88                                     const Elf_Data *secstrs)
  89 {
  90         return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
  91 }
  92
  93 static bool elf_sec__is_a(GElf_Shdr *shdr, Elf_Data *secstrs,
  94                           enum map_type type)
  95 {
  96         switch (type) {
  97         case MAP__FUNCTION:
  98                 return elf_sec__is_text(shdr, secstrs);
  99         case MAP__VARIABLE:
 100                 return elf_sec__is_data(shdr, secstrs);
 101         default:
 102                 return false;
 103         }
 104 }
 105
 106 static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
 107 {
 108         Elf_Scn *sec = NULL;
 109         GElf_Shdr shdr;
 110         size_t cnt = 1;
 111
 112         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 113                 gelf_getshdr(sec, &shdr);
 114
 115                 if ((addr >= shdr.sh_addr) &&
 116                     (addr < (shdr.sh_addr + shdr.sh_size)))
 117                         return cnt;
 118
 119                 ++cnt;
 120         }
 121
 122         return -1;
 123 }
 124
 125 static Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
 126                                     GElf_Shdr *shp, const char *name,
 127                                     size_t *idx)
 128 {
 129         Elf_Scn *sec = NULL;
 130         size_t cnt = 1;
 131
 132         /* Elf is corrupted/truncated, avoid calling elf_strptr. */
 133         if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
 134                 return NULL;
 135
 136         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 137                 char *str;
 138
 139                 gelf_getshdr(sec, shp);
 140                 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
 141                 if (!strcmp(name, str)) {
 142                         if (idx)
 143                                 *idx = cnt;
 144                         break;
 145                 }
 146                 ++cnt;
 147         }
 148
 149         return sec;
 150 }
 151
 152 #define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
 153         for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
 154              idx < nr_entries; \
 155              ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
 156
 157 #define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
 158         for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
 159              idx < nr_entries; \
 160              ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
 161
 162 /*
 163  * We need to check if we have a .dynsym, so that we can handle the
 164  * .plt, synthesizing its symbols, that aren't on the symtabs (be it
 165  * .dynsym or .symtab).
 166  * And always look at the original dso, not at debuginfo packages, that
 167  * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
 168  */
 169 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss, struct map *map,
 170                                 symbol_filter_t filter)
 171 {
 172         uint32_t nr_rel_entries, idx;
 173         GElf_Sym sym;
 174         u64 plt_offset;
 175         GElf_Shdr shdr_plt;
 176         struct symbol *f;
 177         GElf_Shdr shdr_rel_plt, shdr_dynsym;
 178         Elf_Data *reldata, *syms, *symstrs;
 179         Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
 180         size_t dynsym_idx;
 181         GElf_Ehdr ehdr;
 182         char sympltname[1024];
 183         Elf *elf;
 184         int nr = 0, symidx, err = 0;
 185
 186         if (!ss->dynsym)
 187                 return 0;
 188
 189         elf = ss->elf;
 190         ehdr = ss->ehdr;
 191
 192         scn_dynsym = ss->dynsym;
 193         shdr_dynsym = ss->dynshdr;
 194         dynsym_idx = ss->dynsym_idx;
 195
 196         if (scn_dynsym == NULL)
 197                 goto out_elf_end;
 198
 199         scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 200                                           ".rela.plt", NULL);
 201         if (scn_plt_rel == NULL) {
 202                 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 203                                                   ".rel.plt", NULL);
 204                 if (scn_plt_rel == NULL)
 205                         goto out_elf_end;
 206         }
 207
 208         err = -1;
 209
 210         if (shdr_rel_plt.sh_link != dynsym_idx)
 211                 goto out_elf_end;
 212
 213         if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
 214                 goto out_elf_end;
 215
 216         /*
 217          * Fetch the relocation section to find the idxes to the GOT
 218          * and the symbols in the .dynsym they refer to.
 219          */
 220         reldata = elf_getdata(scn_plt_rel, NULL);
 221         if (reldata == NULL)
 222                 goto out_elf_end;
 223
 224         syms = elf_getdata(scn_dynsym, NULL);
 225         if (syms == NULL)
 226                 goto out_elf_end;
 227
 228         scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
 229         if (scn_symstrs == NULL)
 230                 goto out_elf_end;
 231
 232         symstrs = elf_getdata(scn_symstrs, NULL);
 233         if (symstrs == NULL)
 234                 goto out_elf_end;
 235
 236         if (symstrs->d_size == 0)
 237                 goto out_elf_end;
 238
 239         nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
 240         plt_offset = shdr_plt.sh_offset;
 241
 242         if (shdr_rel_plt.sh_type == SHT_RELA) {
 243                 GElf_Rela pos_mem, *pos;
 244
 245                 elf_section__for_each_rela(reldata, pos, pos_mem, idx,
 246                                            nr_rel_entries) {
 247                         symidx = GELF_R_SYM(pos->r_info);
 248                         plt_offset += shdr_plt.sh_entsize;
 249                         gelf_getsym(syms, symidx, &sym);
 250                         snprintf(sympltname, sizeof(sympltname),
 251                                  "%s@plt", elf_sym__name(&sym, symstrs));
 252
 253                         f = symbol__new(plt_offset, shdr_plt.sh_entsize,
 254                                         STB_GLOBAL, sympltname);
 255                         if (!f)
 256                                 goto out_elf_end;
 257
 258                         if (filter && filter(map, f))
 259                                 symbol__delete(f);
 260                         else {
 261                                 symbols__insert(&dso->symbols[map->type], f);
 262                                 ++nr;
 263                         }
 264                 }
 265         } else if (shdr_rel_plt.sh_type == SHT_REL) {
 266                 GElf_Rel pos_mem, *pos;
 267                 elf_section__for_each_rel(reldata, pos, pos_mem, idx,
 268                                           nr_rel_entries) {
 269                         symidx = GELF_R_SYM(pos->r_info);
 270                         plt_offset += shdr_plt.sh_entsize;
 271                         gelf_getsym(syms, symidx, &sym);
 272                         snprintf(sympltname, sizeof(sympltname),
 273                                  "%s@plt", elf_sym__name(&sym, symstrs));
 274
 275                         f = symbol__new(plt_offset, shdr_plt.sh_entsize,
 276                                         STB_GLOBAL, sympltname);
 277                         if (!f)
 278                                 goto out_elf_end;
 279
 280                         if (filter && filter(map, f))
 281                                 symbol__delete(f);
 282                         else {
 283                                 symbols__insert(&dso->symbols[map->type], f);
 284                                 ++nr;
 285                         }
 286                 }
 287         }
 288
 289         err = 0;
 290 out_elf_end:
 291         if (err == 0)
 292                 return nr;
 293         pr_debug("%s: problems reading %s PLT info.\n",
 294                  __func__, dso->long_name);
 295         return 0;
 296 }
 297
 298 /*
 299  * Align offset to 4 bytes as needed for note name and descriptor data.
 300  */
 301 #define NOTE_ALIGN(n) (((n) + 3) & -4U)
 302
 303 static int elf_read_build_id(Elf *elf, void *bf, size_t size)
 304 {
 305         int err = -1;
 306         GElf_Ehdr ehdr;
 307         GElf_Shdr shdr;
 308         Elf_Data *data;
 309         Elf_Scn *sec;
 310         Elf_Kind ek;
 311         void *ptr;
 312
 313         if (size < BUILD_ID_SIZE)
 314                 goto out;
 315
 316         ek = elf_kind(elf);
 317         if (ek != ELF_K_ELF)
 318                 goto out;
 319
 320         if (gelf_getehdr(elf, &ehdr) == NULL) {
 321                 pr_err("%s: cannot get elf header.\n", __func__);
 322                 goto out;
 323         }
 324
 325         /*
 326          * Check following sections for notes:
 327          *   '.note.gnu.build-id'
 328          *   '.notes'
 329          *   '.note' (VDSO specific)
 330          */
 331         do {
 332                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 333                                           ".note.gnu.build-id", NULL);
 334                 if (sec)
 335                         break;
 336
 337                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 338                                           ".notes", NULL);
 339                 if (sec)
 340                         break;
 341
 342                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 343                                           ".note", NULL);
 344                 if (sec)
 345                         break;
 346
 347                 return err;
 348
 349         } while (0);
 350
 351         data = elf_getdata(sec, NULL);
 352         if (data == NULL)
 353                 goto out;
 354
 355         ptr = data->d_buf;
 356         while (ptr < (data->d_buf + data->d_size)) {
 357                 GElf_Nhdr *nhdr = ptr;
 358                 size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
 359                        descsz = NOTE_ALIGN(nhdr->n_descsz);
 360                 const char *name;
 361
 362                 ptr += sizeof(*nhdr);
 363                 name = ptr;
 364                 ptr += namesz;
 365                 if (nhdr->n_type == NT_GNU_BUILD_ID &&
 366                     nhdr->n_namesz == sizeof("GNU")) {
 367                         if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
 368                                 size_t sz = min(size, descsz);
 369                                 memcpy(bf, ptr, sz);
 370                                 memset(bf + sz, 0, size - sz);
 371                                 err = descsz;
 372                                 break;
 373                         }
 374                 }
 375                 ptr += descsz;
 376         }
 377
 378 out:
 379         return err;
 380 }
 381
 382 int filename__read_build_id(const char *filename, void *bf, size_t size)
 383 {
 384         int fd, err = -1;
 385         Elf *elf;
 386
 387         if (size < BUILD_ID_SIZE)
 388                 goto out;
 389
 390         fd = open(filename, O_RDONLY);
 391         if (fd < 0)
 392                 goto out;
 393
 394         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 395         if (elf == NULL) {
 396                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 397                 goto out_close;
 398         }
 399
 400         err = elf_read_build_id(elf, bf, size);
 401
 402         elf_end(elf);
 403 out_close:
 404         close(fd);
 405 out:
 406         return err;
 407 }
 408
 409 int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
 410 {
 411         int fd, err = -1;
 412
 413         if (size < BUILD_ID_SIZE)
 414                 goto out;
 415
 416         fd = open(filename, O_RDONLY);
 417         if (fd < 0)
 418                 goto out;
 419
 420         while (1) {
 421                 char bf[BUFSIZ];
 422                 GElf_Nhdr nhdr;
 423                 size_t namesz, descsz;
 424
 425                 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
 426                         break;
 427
 428                 namesz = NOTE_ALIGN(nhdr.n_namesz);
 429                 descsz = NOTE_ALIGN(nhdr.n_descsz);
 430                 if (nhdr.n_type == NT_GNU_BUILD_ID &&
 431                     nhdr.n_namesz == sizeof("GNU")) {
 432                         if (read(fd, bf, namesz) != (ssize_t)namesz)
 433                                 break;
 434                         if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
 435                                 size_t sz = min(descsz, size);
 436                                 if (read(fd, build_id, sz) == (ssize_t)sz) {
 437                                         memset(build_id + sz, 0, size - sz);
 438                                         err = 0;
 439                                         break;
 440                                 }
 441                         } else if (read(fd, bf, descsz) != (ssize_t)descsz)
 442                                 break;
 443                 } else {
 444                         int n = namesz + descsz;
 445                         if (read(fd, bf, n) != n)
 446                                 break;
 447                 }
 448         }
 449         close(fd);
 450 out:
 451         return err;
 452 }
 453
 454 int filename__read_debuglink(const char *filename, char *debuglink,
 455                              size_t size)
 456 {
 457         int fd, err = -1;
 458         Elf *elf;
 459         GElf_Ehdr ehdr;
 460         GElf_Shdr shdr;
 461         Elf_Data *data;
 462         Elf_Scn *sec;
 463         Elf_Kind ek;
 464
 465         fd = open(filename, O_RDONLY);
 466         if (fd < 0)
 467                 goto out;
 468
 469         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 470         if (elf == NULL) {
 471                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 472                 goto out_close;
 473         }
 474
 475         ek = elf_kind(elf);
 476         if (ek != ELF_K_ELF)
 477                 goto out_close;
 478
 479         if (gelf_getehdr(elf, &ehdr) == NULL) {
 480                 pr_err("%s: cannot get elf header.\n", __func__);
 481                 goto out_close;
 482         }
 483
 484         sec = elf_section_by_name(elf, &ehdr, &shdr,
 485                                   ".gnu_debuglink", NULL);
 486         if (sec == NULL)
 487                 goto out_close;
 488
 489         data = elf_getdata(sec, NULL);
 490         if (data == NULL)
 491                 goto out_close;
 492
 493         /* the start of this section is a zero-terminated string */
 494         strncpy(debuglink, data->d_buf, size);
 495
 496         elf_end(elf);
 497
 498 out_close:
 499         close(fd);
 500 out:
 501         return err;
 502 }
 503
 504 static int dso__swap_init(struct dso *dso, unsigned char eidata)
 505 {
 506         static unsigned int const endian = 1;
 507
 508         dso->needs_swap = DSO_SWAP__NO;
 509
 510         switch (eidata) {
 511         case ELFDATA2LSB:
 512                 /* We are big endian, DSO is little endian. */
 513                 if (*(unsigned char const *)&endian != 1)
 514                         dso->needs_swap = DSO_SWAP__YES;
 515                 break;
 516
 517         case ELFDATA2MSB:
 518                 /* We are little endian, DSO is big endian. */
 519                 if (*(unsigned char const *)&endian != 0)
 520                         dso->needs_swap = DSO_SWAP__YES;
 521                 break;
 522
 523         default:
 524                 pr_err("unrecognized DSO data encoding %d\n", eidata);
 525                 return -EINVAL;
 526         }
 527
 528         return 0;
 529 }
 530
 531 bool symsrc__possibly_runtime(struct symsrc *ss)
 532 {
 533         return ss->dynsym || ss->opdsec;
 534 }
 535
 536 bool symsrc__has_symtab(struct symsrc *ss)
 537 {
 538         return ss->symtab != NULL;
 539 }
 540
 541 void symsrc__destroy(struct symsrc *ss)
 542 {
 543         free(ss->name);
 544         elf_end(ss->elf);
 545         close(ss->fd);
 546 }
 547
 548 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
 549                  enum dso_binary_type type)
 550 {
 551         int err = -1;
 552         GElf_Ehdr ehdr;
 553         Elf *elf;
 554         int fd;
 555
 556         fd = open(name, O_RDONLY);
 557         if (fd < 0)
 558                 return -1;
 559
 560         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 561         if (elf == NULL) {
 562                 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
 563                 goto out_close;
 564         }
 565
 566         if (gelf_getehdr(elf, &ehdr) == NULL) {
 567                 pr_debug("%s: cannot get elf header.\n", __func__);
 568                 goto out_elf_end;
 569         }
 570
 571         if (dso__swap_init(dso, ehdr.e_ident[EI_DATA]))
 572                 goto out_elf_end;
 573
 574         /* Always reject images with a mismatched build-id: */
 575         if (dso->has_build_id) {
 576                 u8 build_id[BUILD_ID_SIZE];
 577
 578                 if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0)
 579                         goto out_elf_end;
 580
 581                 if (!dso__build_id_equal(dso, build_id))
 582                         goto out_elf_end;
 583         }
 584
 585         ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
 586                         NULL);
 587         if (ss->symshdr.sh_type != SHT_SYMTAB)
 588                 ss->symtab = NULL;
 589
 590         ss->dynsym_idx = 0;
 591         ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
 592                         &ss->dynsym_idx);
 593         if (ss->dynshdr.sh_type != SHT_DYNSYM)
 594                 ss->dynsym = NULL;
 595
 596         ss->opdidx = 0;
 597         ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
 598                         &ss->opdidx);
 599         if (ss->opdshdr.sh_type != SHT_PROGBITS)
 600                 ss->opdsec = NULL;
 601
 602         if (dso->kernel == DSO_TYPE_USER) {
 603                 GElf_Shdr shdr;
 604                 ss->adjust_symbols = (ehdr.e_type == ET_EXEC ||
 605                                 elf_section_by_name(elf, &ehdr, &shdr,
 606                                                      ".gnu.prelink_undo",
 607                                                      NULL) != NULL);
 608         } else {
 609                 ss->adjust_symbols = 0;
 610         }
 611
 612         ss->name   = strdup(name);
 613         if (!ss->name)
 614                 goto out_elf_end;
 615
 616         ss->elf    = elf;
 617         ss->fd     = fd;
 618         ss->ehdr   = ehdr;
 619         ss->type   = type;
 620
 621         return 0;
 622
 623 out_elf_end:
 624         elf_end(elf);
 625 out_close:
 626         close(fd);
 627         return err;
 628 }
 629
 630 int dso__load_sym(struct dso *dso, struct map *map,
 631                   struct symsrc *syms_ss, struct symsrc *runtime_ss,
 632                   symbol_filter_t filter, int kmodule)
 633 {
 634         struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
 635         struct map *curr_map = map;
 636         struct dso *curr_dso = dso;
 637         Elf_Data *symstrs, *secstrs;
 638         uint32_t nr_syms;
 639         int err = -1;
 640         uint32_t idx;
 641         GElf_Ehdr ehdr;
 642         GElf_Shdr shdr;
 643         Elf_Data *syms, *opddata = NULL;
 644         GElf_Sym sym;
 645         Elf_Scn *sec, *sec_strndx;
 646         Elf *elf;
 647         int nr = 0;
 648
 649         dso->symtab_type = syms_ss->type;
 650
 651         if (!syms_ss->symtab) {
 652                 syms_ss->symtab  = syms_ss->dynsym;
 653                 syms_ss->symshdr = syms_ss->dynshdr;
 654         }
 655
 656         elf = syms_ss->elf;
 657         ehdr = syms_ss->ehdr;
 658         sec = syms_ss->symtab;
 659         shdr = syms_ss->symshdr;
 660
 661         if (runtime_ss->opdsec)
 662                 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
 663
 664         syms = elf_getdata(sec, NULL);
 665         if (syms == NULL)
 666                 goto out_elf_end;
 667
 668         sec = elf_getscn(elf, shdr.sh_link);
 669         if (sec == NULL)
 670                 goto out_elf_end;
 671
 672         symstrs = elf_getdata(sec, NULL);
 673         if (symstrs == NULL)
 674                 goto out_elf_end;
 675
 676         sec_strndx = elf_getscn(elf, ehdr.e_shstrndx);
 677         if (sec_strndx == NULL)
 678                 goto out_elf_end;
 679
 680         secstrs = elf_getdata(sec_strndx, NULL);
 681         if (secstrs == NULL)
 682                 goto out_elf_end;
 683
 684         nr_syms = shdr.sh_size / shdr.sh_entsize;
 685
 686         memset(&sym, 0, sizeof(sym));
 687         dso->adjust_symbols = runtime_ss->adjust_symbols;
 688         elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
 689                 struct symbol *f;
 690                 const char *elf_name = elf_sym__name(&sym, symstrs);
 691                 char *demangled = NULL;
 692                 int is_label = elf_sym__is_label(&sym);
 693                 const char *section_name;
 694                 bool used_opd = false;
 695
 696                 if (kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
 697                     strcmp(elf_name, kmap->ref_reloc_sym->name) == 0)
 698                         kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
 699
 700                 if (!is_label && !elf_sym__is_a(&sym, map->type))
 701                         continue;
 702
 703                 /* Reject ARM ELF "mapping symbols": these aren't unique and
 704                  * don't identify functions, so will confuse the profile
 705                  * output: */
 706                 if (ehdr.e_machine == EM_ARM) {
 707                         if (!strcmp(elf_name, "$a") ||
 708                             !strcmp(elf_name, "$d") ||
 709                             !strcmp(elf_name, "$t"))
 710                                 continue;
 711                 }
 712
 713                 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
 714                         u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
 715                         u64 *opd = opddata->d_buf + offset;
 716                         sym.st_value = DSO__SWAP(dso, u64, *opd);
 717                         sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
 718                                         sym.st_value);
 719                         used_opd = true;
 720                 }
 721
 722                 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
 723                 if (!sec)
 724                         goto out_elf_end;
 725
 726                 gelf_getshdr(sec, &shdr);
 727
 728                 if (is_label && !elf_sec__is_a(&shdr, secstrs, map->type))
 729                         continue;
 730
 731                 section_name = elf_sec__name(&shdr, secstrs);
 732
 733                 /* On ARM, symbols for thumb functions have 1 added to
 734                  * the symbol address as a flag - remove it */
 735                 if ((ehdr.e_machine == EM_ARM) &&
 736                     (map->type == MAP__FUNCTION) &&
 737                     (sym.st_value & 1))
 738                         --sym.st_value;
 739
 740                 if (dso->kernel != DSO_TYPE_USER || kmodule) {
 741                         char dso_name[PATH_MAX];
 742
 743                         if (strcmp(section_name,
 744                                    (curr_dso->short_name +
 745                                     dso->short_name_len)) == 0)
 746                                 goto new_symbol;
 747
 748                         if (strcmp(section_name, ".text") == 0) {
 749                                 curr_map = map;
 750                                 curr_dso = dso;
 751                                 goto new_symbol;
 752                         }
 753
 754                         snprintf(dso_name, sizeof(dso_name),
 755                                  "%s%s", dso->short_name, section_name);
 756
 757                         curr_map = map_groups__find_by_name(kmap->kmaps, map->type, dso_name);
 758                         if (curr_map == NULL) {
 759                                 u64 start = sym.st_value;
 760
 761                                 if (kmodule)
 762                                         start += map->start + shdr.sh_offset;
 763
 764                                 curr_dso = dso__new(dso_name);
 765                                 if (curr_dso == NULL)
 766                                         goto out_elf_end;
 767                                 curr_dso->kernel = dso->kernel;
 768                                 curr_dso->long_name = dso->long_name;
 769                                 curr_dso->long_name_len = dso->long_name_len;
 770                                 curr_map = map__new2(start, curr_dso,
 771                                                      map->type);
 772                                 if (curr_map == NULL) {
 773                                         dso__delete(curr_dso);
 774                                         goto out_elf_end;
 775                                 }
 776                                 curr_map->map_ip = identity__map_ip;
 777                                 curr_map->unmap_ip = identity__map_ip;
 778                                 curr_dso->symtab_type = dso->symtab_type;
 779                                 map_groups__insert(kmap->kmaps, curr_map);
 780                                 dsos__add(&dso->node, curr_dso);
 781                                 dso__set_loaded(curr_dso, map->type);
 782                         } else
 783                                 curr_dso = curr_map->dso;
 784
 785                         goto new_symbol;
 786                 }
 787
 788                 if ((used_opd && runtime_ss->adjust_symbols)
 789                                 || (!used_opd && syms_ss->adjust_symbols)) {
 790                         pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
 791                                   "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
 792                                   (u64)sym.st_value, (u64)shdr.sh_addr,
 793                                   (u64)shdr.sh_offset);
 794                         sym.st_value -= shdr.sh_addr - shdr.sh_offset;
 795                 }
 796                 /*
 797                  * We need to figure out if the object was created from C++ sources
 798                  * DWARF DW_compile_unit has this, but we don't always have access
 799                  * to it...
 800                  */
 801                 demangled = bfd_demangle(NULL, elf_name, DMGL_PARAMS | DMGL_ANSI);
 802                 if (demangled != NULL)
 803                         elf_name = demangled;
 804 new_symbol:
 805                 f = symbol__new(sym.st_value, sym.st_size,
 806                                 GELF_ST_BIND(sym.st_info), elf_name);
 807                 free(demangled);
 808                 if (!f)
 809                         goto out_elf_end;
 810
 811                 if (filter && filter(curr_map, f))
 812                         symbol__delete(f);
 813                 else {
 814                         symbols__insert(&curr_dso->symbols[curr_map->type], f);
 815                         nr++;
 816                 }
 817         }
 818
 819         /*
 820          * For misannotated, zeroed, ASM function sizes.
 821          */
 822         if (nr > 0) {
 823                 symbols__fixup_duplicate(&dso->symbols[map->type]);
 824                 symbols__fixup_end(&dso->symbols[map->type]);
 825                 if (kmap) {
 826                         /*
 827                          * We need to fixup this here too because we create new
 828                          * maps here, for things like vsyscall sections.
 829                          */
 830                         __map_groups__fixup_end(kmap->kmaps, map->type);
 831                 }
 832         }
 833         err = nr;
 834 out_elf_end:
 835         return err;
 836 }
 837
 838 void symbol__elf_init(void)
 839 {
 840         elf_version(EV_CURRENT);
 841 }