linux/tools/perf/util/symbol-elf.c
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   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 "debug.h"
  10
  11#ifndef NT_GNU_BUILD_ID
  12#define NT_GNU_BUILD_ID 3
  13#endif
  14
  15/**
  16 * elf_symtab__for_each_symbol - iterate thru all the symbols
  17 *
  18 * @syms: struct elf_symtab instance to iterate
  19 * @idx: uint32_t idx
  20 * @sym: GElf_Sym iterator
  21 */
  22#define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
  23        for (idx = 0, gelf_getsym(syms, idx, &sym);\
  24             idx < nr_syms; \
  25             idx++, gelf_getsym(syms, idx, &sym))
  26
  27static inline uint8_t elf_sym__type(const GElf_Sym *sym)
  28{
  29        return GELF_ST_TYPE(sym->st_info);
  30}
  31
  32static inline int elf_sym__is_function(const GElf_Sym *sym)
  33{
  34        return elf_sym__type(sym) == STT_FUNC &&
  35               sym->st_name != 0 &&
  36               sym->st_shndx != SHN_UNDEF;
  37}
  38
  39static inline bool elf_sym__is_object(const GElf_Sym *sym)
  40{
  41        return elf_sym__type(sym) == STT_OBJECT &&
  42                sym->st_name != 0 &&
  43                sym->st_shndx != SHN_UNDEF;
  44}
  45
  46static inline int elf_sym__is_label(const GElf_Sym *sym)
  47{
  48        return elf_sym__type(sym) == STT_NOTYPE &&
  49                sym->st_name != 0 &&
  50                sym->st_shndx != SHN_UNDEF &&
  51                sym->st_shndx != SHN_ABS;
  52}
  53
  54static bool elf_sym__is_a(GElf_Sym *sym, enum map_type type)
  55{
  56        switch (type) {
  57        case MAP__FUNCTION:
  58                return elf_sym__is_function(sym);
  59        case MAP__VARIABLE:
  60                return elf_sym__is_object(sym);
  61        default:
  62                return false;
  63        }
  64}
  65
  66static inline const char *elf_sym__name(const GElf_Sym *sym,
  67                                        const Elf_Data *symstrs)
  68{
  69        return symstrs->d_buf + sym->st_name;
  70}
  71
  72static inline const char *elf_sec__name(const GElf_Shdr *shdr,
  73                                        const Elf_Data *secstrs)
  74{
  75        return secstrs->d_buf + shdr->sh_name;
  76}
  77
  78static inline int elf_sec__is_text(const GElf_Shdr *shdr,
  79                                        const Elf_Data *secstrs)
  80{
  81        return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
  82}
  83
  84static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
  85                                    const Elf_Data *secstrs)
  86{
  87        return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
  88}
  89
  90static bool elf_sec__is_a(GElf_Shdr *shdr, Elf_Data *secstrs,
  91                          enum map_type type)
  92{
  93        switch (type) {
  94        case MAP__FUNCTION:
  95                return elf_sec__is_text(shdr, secstrs);
  96        case MAP__VARIABLE:
  97                return elf_sec__is_data(shdr, secstrs);
  98        default:
  99                return false;
 100        }
 101}
 102
 103static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
 104{
 105        Elf_Scn *sec = NULL;
 106        GElf_Shdr shdr;
 107        size_t cnt = 1;
 108
 109        while ((sec = elf_nextscn(elf, sec)) != NULL) {
 110                gelf_getshdr(sec, &shdr);
 111
 112                if ((addr >= shdr.sh_addr) &&
 113                    (addr < (shdr.sh_addr + shdr.sh_size)))
 114                        return cnt;
 115
 116                ++cnt;
 117        }
 118
 119        return -1;
 120}
 121
 122static Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
 123                                    GElf_Shdr *shp, const char *name,
 124                                    size_t *idx)
 125{
 126        Elf_Scn *sec = NULL;
 127        size_t cnt = 1;
 128
 129        /* Elf is corrupted/truncated, avoid calling elf_strptr. */
 130        if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
 131                return NULL;
 132
 133        while ((sec = elf_nextscn(elf, sec)) != NULL) {
 134                char *str;
 135
 136                gelf_getshdr(sec, shp);
 137                str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
 138                if (!strcmp(name, str)) {
 139                        if (idx)
 140                                *idx = cnt;
 141                        break;
 142                }
 143                ++cnt;
 144        }
 145
 146        return sec;
 147}
 148
 149#define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
 150        for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
 151             idx < nr_entries; \
 152             ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
 153
 154#define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
 155        for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
 156             idx < nr_entries; \
 157             ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
 158
 159/*
 160 * We need to check if we have a .dynsym, so that we can handle the
 161 * .plt, synthesizing its symbols, that aren't on the symtabs (be it
 162 * .dynsym or .symtab).
 163 * And always look at the original dso, not at debuginfo packages, that
 164 * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
 165 */
 166int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss, struct map *map,
 167                                symbol_filter_t filter)
 168{
 169        uint32_t nr_rel_entries, idx;
 170        GElf_Sym sym;
 171        u64 plt_offset;
 172        GElf_Shdr shdr_plt;
 173        struct symbol *f;
 174        GElf_Shdr shdr_rel_plt, shdr_dynsym;
 175        Elf_Data *reldata, *syms, *symstrs;
 176        Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
 177        size_t dynsym_idx;
 178        GElf_Ehdr ehdr;
 179        char sympltname[1024];
 180        Elf *elf;
 181        int nr = 0, symidx, err = 0;
 182
 183        if (!ss->dynsym)
 184                return 0;
 185
 186        elf = ss->elf;
 187        ehdr = ss->ehdr;
 188
 189        scn_dynsym = ss->dynsym;
 190        shdr_dynsym = ss->dynshdr;
 191        dynsym_idx = ss->dynsym_idx;
 192
 193        if (scn_dynsym == NULL)
 194                goto out_elf_end;
 195
 196        scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 197                                          ".rela.plt", NULL);
 198        if (scn_plt_rel == NULL) {
 199                scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 200                                                  ".rel.plt", NULL);
 201                if (scn_plt_rel == NULL)
 202                        goto out_elf_end;
 203        }
 204
 205        err = -1;
 206
 207        if (shdr_rel_plt.sh_link != dynsym_idx)
 208                goto out_elf_end;
 209
 210        if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
 211                goto out_elf_end;
 212
 213        /*
 214         * Fetch the relocation section to find the idxes to the GOT
 215         * and the symbols in the .dynsym they refer to.
 216         */
 217        reldata = elf_getdata(scn_plt_rel, NULL);
 218        if (reldata == NULL)
 219                goto out_elf_end;
 220
 221        syms = elf_getdata(scn_dynsym, NULL);
 222        if (syms == NULL)
 223                goto out_elf_end;
 224
 225        scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
 226        if (scn_symstrs == NULL)
 227                goto out_elf_end;
 228
 229        symstrs = elf_getdata(scn_symstrs, NULL);
 230        if (symstrs == NULL)
 231                goto out_elf_end;
 232
 233        if (symstrs->d_size == 0)
 234                goto out_elf_end;
 235
 236        nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
 237        plt_offset = shdr_plt.sh_offset;
 238
 239        if (shdr_rel_plt.sh_type == SHT_RELA) {
 240                GElf_Rela pos_mem, *pos;
 241
 242                elf_section__for_each_rela(reldata, pos, pos_mem, idx,
 243                                           nr_rel_entries) {
 244                        symidx = GELF_R_SYM(pos->r_info);
 245                        plt_offset += shdr_plt.sh_entsize;
 246                        gelf_getsym(syms, symidx, &sym);
 247                        snprintf(sympltname, sizeof(sympltname),
 248                                 "%s@plt", elf_sym__name(&sym, symstrs));
 249
 250                        f = symbol__new(plt_offset, shdr_plt.sh_entsize,
 251                                        STB_GLOBAL, sympltname);
 252                        if (!f)
 253                                goto out_elf_end;
 254
 255                        if (filter && filter(map, f))
 256                                symbol__delete(f);
 257                        else {
 258                                symbols__insert(&dso->symbols[map->type], f);
 259                                ++nr;
 260                        }
 261                }
 262        } else if (shdr_rel_plt.sh_type == SHT_REL) {
 263                GElf_Rel pos_mem, *pos;
 264                elf_section__for_each_rel(reldata, pos, pos_mem, idx,
 265                                          nr_rel_entries) {
 266                        symidx = GELF_R_SYM(pos->r_info);
 267                        plt_offset += shdr_plt.sh_entsize;
 268                        gelf_getsym(syms, symidx, &sym);
 269                        snprintf(sympltname, sizeof(sympltname),
 270                                 "%s@plt", elf_sym__name(&sym, symstrs));
 271
 272                        f = symbol__new(plt_offset, shdr_plt.sh_entsize,
 273                                        STB_GLOBAL, sympltname);
 274                        if (!f)
 275                                goto out_elf_end;
 276
 277                        if (filter && filter(map, f))
 278                                symbol__delete(f);
 279                        else {
 280                                symbols__insert(&dso->symbols[map->type], f);
 281                                ++nr;
 282                        }
 283                }
 284        }
 285
 286        err = 0;
 287out_elf_end:
 288        if (err == 0)
 289                return nr;
 290        pr_debug("%s: problems reading %s PLT info.\n",
 291                 __func__, dso->long_name);
 292        return 0;
 293}
 294
 295/*
 296 * Align offset to 4 bytes as needed for note name and descriptor data.
 297 */
 298#define NOTE_ALIGN(n) (((n) + 3) & -4U)
 299
 300static int elf_read_build_id(Elf *elf, void *bf, size_t size)
 301{
 302        int err = -1;
 303        GElf_Ehdr ehdr;
 304        GElf_Shdr shdr;
 305        Elf_Data *data;
 306        Elf_Scn *sec;
 307        Elf_Kind ek;
 308        void *ptr;
 309
 310        if (size < BUILD_ID_SIZE)
 311                goto out;
 312
 313        ek = elf_kind(elf);
 314        if (ek != ELF_K_ELF)
 315                goto out;
 316
 317        if (gelf_getehdr(elf, &ehdr) == NULL) {
 318                pr_err("%s: cannot get elf header.\n", __func__);
 319                goto out;
 320        }
 321
 322        /*
 323         * Check following sections for notes:
 324         *   '.note.gnu.build-id'
 325         *   '.notes'
 326         *   '.note' (VDSO specific)
 327         */
 328        do {
 329                sec = elf_section_by_name(elf, &ehdr, &shdr,
 330                                          ".note.gnu.build-id", NULL);
 331                if (sec)
 332                        break;
 333
 334                sec = elf_section_by_name(elf, &ehdr, &shdr,
 335                                          ".notes", NULL);
 336                if (sec)
 337                        break;
 338
 339                sec = elf_section_by_name(elf, &ehdr, &shdr,
 340                                          ".note", NULL);
 341                if (sec)
 342                        break;
 343
 344                return err;
 345
 346        } while (0);
 347
 348        data = elf_getdata(sec, NULL);
 349        if (data == NULL)
 350                goto out;
 351
 352        ptr = data->d_buf;
 353        while (ptr < (data->d_buf + data->d_size)) {
 354                GElf_Nhdr *nhdr = ptr;
 355                size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
 356                       descsz = NOTE_ALIGN(nhdr->n_descsz);
 357                const char *name;
 358
 359                ptr += sizeof(*nhdr);
 360                name = ptr;
 361                ptr += namesz;
 362                if (nhdr->n_type == NT_GNU_BUILD_ID &&
 363                    nhdr->n_namesz == sizeof("GNU")) {
 364                        if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
 365                                size_t sz = min(size, descsz);
 366                                memcpy(bf, ptr, sz);
 367                                memset(bf + sz, 0, size - sz);
 368                                err = descsz;
 369                                break;
 370                        }
 371                }
 372                ptr += descsz;
 373        }
 374
 375out:
 376        return err;
 377}
 378
 379int filename__read_build_id(const char *filename, void *bf, size_t size)
 380{
 381        int fd, err = -1;
 382        Elf *elf;
 383
 384        if (size < BUILD_ID_SIZE)
 385                goto out;
 386
 387        fd = open(filename, O_RDONLY);
 388        if (fd < 0)
 389                goto out;
 390
 391        elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 392        if (elf == NULL) {
 393                pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 394                goto out_close;
 395        }
 396
 397        err = elf_read_build_id(elf, bf, size);
 398
 399        elf_end(elf);
 400out_close:
 401        close(fd);
 402out:
 403        return err;
 404}
 405
 406int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
 407{
 408        int fd, err = -1;
 409
 410        if (size < BUILD_ID_SIZE)
 411                goto out;
 412
 413        fd = open(filename, O_RDONLY);
 414        if (fd < 0)
 415                goto out;
 416
 417        while (1) {
 418                char bf[BUFSIZ];
 419                GElf_Nhdr nhdr;
 420                size_t namesz, descsz;
 421
 422                if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
 423                        break;
 424
 425                namesz = NOTE_ALIGN(nhdr.n_namesz);
 426                descsz = NOTE_ALIGN(nhdr.n_descsz);
 427                if (nhdr.n_type == NT_GNU_BUILD_ID &&
 428                    nhdr.n_namesz == sizeof("GNU")) {
 429                        if (read(fd, bf, namesz) != (ssize_t)namesz)
 430                                break;
 431                        if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
 432                                size_t sz = min(descsz, size);
 433                                if (read(fd, build_id, sz) == (ssize_t)sz) {
 434                                        memset(build_id + sz, 0, size - sz);
 435                                        err = 0;
 436                                        break;
 437                                }
 438                        } else if (read(fd, bf, descsz) != (ssize_t)descsz)
 439                                break;
 440                } else {
 441                        int n = namesz + descsz;
 442                        if (read(fd, bf, n) != n)
 443                                break;
 444                }
 445        }
 446        close(fd);
 447out:
 448        return err;
 449}
 450
 451int filename__read_debuglink(const char *filename, char *debuglink,
 452                             size_t size)
 453{
 454        int fd, err = -1;
 455        Elf *elf;
 456        GElf_Ehdr ehdr;
 457        GElf_Shdr shdr;
 458        Elf_Data *data;
 459        Elf_Scn *sec;
 460        Elf_Kind ek;
 461
 462        fd = open(filename, O_RDONLY);
 463        if (fd < 0)
 464                goto out;
 465
 466        elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 467        if (elf == NULL) {
 468                pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 469                goto out_close;
 470        }
 471
 472        ek = elf_kind(elf);
 473        if (ek != ELF_K_ELF)
 474                goto out_close;
 475
 476        if (gelf_getehdr(elf, &ehdr) == NULL) {
 477                pr_err("%s: cannot get elf header.\n", __func__);
 478                goto out_close;
 479        }
 480
 481        sec = elf_section_by_name(elf, &ehdr, &shdr,
 482                                  ".gnu_debuglink", NULL);
 483        if (sec == NULL)
 484                goto out_close;
 485
 486        data = elf_getdata(sec, NULL);
 487        if (data == NULL)
 488                goto out_close;
 489
 490        /* the start of this section is a zero-terminated string */
 491        strncpy(debuglink, data->d_buf, size);
 492
 493        elf_end(elf);
 494
 495out_close:
 496        close(fd);
 497out:
 498        return err;
 499}
 500
 501static int dso__swap_init(struct dso *dso, unsigned char eidata)
 502{
 503        static unsigned int const endian = 1;
 504
 505        dso->needs_swap = DSO_SWAP__NO;
 506
 507        switch (eidata) {
 508        case ELFDATA2LSB:
 509                /* We are big endian, DSO is little endian. */
 510                if (*(unsigned char const *)&endian != 1)
 511                        dso->needs_swap = DSO_SWAP__YES;
 512                break;
 513
 514        case ELFDATA2MSB:
 515                /* We are little endian, DSO is big endian. */
 516                if (*(unsigned char const *)&endian != 0)
 517                        dso->needs_swap = DSO_SWAP__YES;
 518                break;
 519
 520        default:
 521                pr_err("unrecognized DSO data encoding %d\n", eidata);
 522                return -EINVAL;
 523        }
 524
 525        return 0;
 526}
 527
 528bool symsrc__possibly_runtime(struct symsrc *ss)
 529{
 530        return ss->dynsym || ss->opdsec;
 531}
 532
 533bool symsrc__has_symtab(struct symsrc *ss)
 534{
 535        return ss->symtab != NULL;
 536}
 537
 538void symsrc__destroy(struct symsrc *ss)
 539{
 540        free(ss->name);
 541        elf_end(ss->elf);
 542        close(ss->fd);
 543}
 544
 545int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
 546                 enum dso_binary_type type)
 547{
 548        int err = -1;
 549        GElf_Ehdr ehdr;
 550        Elf *elf;
 551        int fd;
 552
 553        fd = open(name, O_RDONLY);
 554        if (fd < 0)
 555                return -1;
 556
 557        elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 558        if (elf == NULL) {
 559                pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
 560                goto out_close;
 561        }
 562
 563        if (gelf_getehdr(elf, &ehdr) == NULL) {
 564                pr_debug("%s: cannot get elf header.\n", __func__);
 565                goto out_elf_end;
 566        }
 567
 568        if (dso__swap_init(dso, ehdr.e_ident[EI_DATA]))
 569                goto out_elf_end;
 570
 571        /* Always reject images with a mismatched build-id: */
 572        if (dso->has_build_id) {
 573                u8 build_id[BUILD_ID_SIZE];
 574
 575                if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0)
 576                        goto out_elf_end;
 577
 578                if (!dso__build_id_equal(dso, build_id))
 579                        goto out_elf_end;
 580        }
 581
 582        ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
 583                        NULL);
 584        if (ss->symshdr.sh_type != SHT_SYMTAB)
 585                ss->symtab = NULL;
 586
 587        ss->dynsym_idx = 0;
 588        ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
 589                        &ss->dynsym_idx);
 590        if (ss->dynshdr.sh_type != SHT_DYNSYM)
 591                ss->dynsym = NULL;
 592
 593        ss->opdidx = 0;
 594        ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
 595                        &ss->opdidx);
 596        if (ss->opdshdr.sh_type != SHT_PROGBITS)
 597                ss->opdsec = NULL;
 598
 599        if (dso->kernel == DSO_TYPE_USER) {
 600                GElf_Shdr shdr;
 601                ss->adjust_symbols = (ehdr.e_type == ET_EXEC ||
 602                                elf_section_by_name(elf, &ehdr, &shdr,
 603                                                     ".gnu.prelink_undo",
 604                                                     NULL) != NULL);
 605        } else {
 606                ss->adjust_symbols = 0;
 607        }
 608
 609        ss->name   = strdup(name);
 610        if (!ss->name)
 611                goto out_elf_end;
 612
 613        ss->elf    = elf;
 614        ss->fd     = fd;
 615        ss->ehdr   = ehdr;
 616        ss->type   = type;
 617
 618        return 0;
 619
 620out_elf_end:
 621        elf_end(elf);
 622out_close:
 623        close(fd);
 624        return err;
 625}
 626
 627int dso__load_sym(struct dso *dso, struct map *map,
 628                  struct symsrc *syms_ss, struct symsrc *runtime_ss,
 629                  symbol_filter_t filter, int kmodule)
 630{
 631        struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
 632        struct map *curr_map = map;
 633        struct dso *curr_dso = dso;
 634        Elf_Data *symstrs, *secstrs;
 635        uint32_t nr_syms;
 636        int err = -1;
 637        uint32_t idx;
 638        GElf_Ehdr ehdr;
 639        GElf_Shdr shdr;
 640        Elf_Data *syms, *opddata = NULL;
 641        GElf_Sym sym;
 642        Elf_Scn *sec, *sec_strndx;
 643        Elf *elf;
 644        int nr = 0;
 645
 646        dso->symtab_type = syms_ss->type;
 647
 648        if (!syms_ss->symtab) {
 649                syms_ss->symtab  = syms_ss->dynsym;
 650                syms_ss->symshdr = syms_ss->dynshdr;
 651        }
 652
 653        elf = syms_ss->elf;
 654        ehdr = syms_ss->ehdr;
 655        sec = syms_ss->symtab;
 656        shdr = syms_ss->symshdr;
 657
 658        if (runtime_ss->opdsec)
 659                opddata = elf_rawdata(runtime_ss->opdsec, NULL);
 660
 661        syms = elf_getdata(sec, NULL);
 662        if (syms == NULL)
 663                goto out_elf_end;
 664
 665        sec = elf_getscn(elf, shdr.sh_link);
 666        if (sec == NULL)
 667                goto out_elf_end;
 668
 669        symstrs = elf_getdata(sec, NULL);
 670        if (symstrs == NULL)
 671                goto out_elf_end;
 672
 673        sec_strndx = elf_getscn(elf, ehdr.e_shstrndx);
 674        if (sec_strndx == NULL)
 675                goto out_elf_end;
 676
 677        secstrs = elf_getdata(sec_strndx, NULL);
 678        if (secstrs == NULL)
 679                goto out_elf_end;
 680
 681        nr_syms = shdr.sh_size / shdr.sh_entsize;
 682
 683        memset(&sym, 0, sizeof(sym));
 684        dso->adjust_symbols = runtime_ss->adjust_symbols;
 685        elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
 686                struct symbol *f;
 687                const char *elf_name = elf_sym__name(&sym, symstrs);
 688                char *demangled = NULL;
 689                int is_label = elf_sym__is_label(&sym);
 690                const char *section_name;
 691                bool used_opd = false;
 692
 693                if (kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
 694                    strcmp(elf_name, kmap->ref_reloc_sym->name) == 0)
 695                        kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
 696
 697                if (!is_label && !elf_sym__is_a(&sym, map->type))
 698                        continue;
 699
 700                /* Reject ARM ELF "mapping symbols": these aren't unique and
 701                 * don't identify functions, so will confuse the profile
 702                 * output: */
 703                if (ehdr.e_machine == EM_ARM) {
 704                        if (!strcmp(elf_name, "$a") ||
 705                            !strcmp(elf_name, "$d") ||
 706                            !strcmp(elf_name, "$t"))
 707                                continue;
 708                }
 709
 710                if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
 711                        u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
 712                        u64 *opd = opddata->d_buf + offset;
 713                        sym.st_value = DSO__SWAP(dso, u64, *opd);
 714                        sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
 715                                        sym.st_value);
 716                        used_opd = true;
 717                }
 718                /*
 719                 * When loading symbols in a data mapping, ABS symbols (which
 720                 * has a value of SHN_ABS in its st_shndx) failed at
 721                 * elf_getscn().  And it marks the loading as a failure so
 722                 * already loaded symbols cannot be fixed up.
 723                 *
 724                 * I'm not sure what should be done. Just ignore them for now.
 725                 * - Namhyung Kim
 726                 */
 727                if (sym.st_shndx == SHN_ABS)
 728                        continue;
 729
 730                sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
 731                if (!sec)
 732                        goto out_elf_end;
 733
 734                gelf_getshdr(sec, &shdr);
 735
 736                if (is_label && !elf_sec__is_a(&shdr, secstrs, map->type))
 737                        continue;
 738
 739                section_name = elf_sec__name(&shdr, secstrs);
 740
 741                /* On ARM, symbols for thumb functions have 1 added to
 742                 * the symbol address as a flag - remove it */
 743                if ((ehdr.e_machine == EM_ARM) &&
 744                    (map->type == MAP__FUNCTION) &&
 745                    (sym.st_value & 1))
 746                        --sym.st_value;
 747
 748                if (dso->kernel != DSO_TYPE_USER || kmodule) {
 749                        char dso_name[PATH_MAX];
 750
 751                        if (strcmp(section_name,
 752                                   (curr_dso->short_name +
 753                                    dso->short_name_len)) == 0)
 754                                goto new_symbol;
 755
 756                        if (strcmp(section_name, ".text") == 0) {
 757                                curr_map = map;
 758                                curr_dso = dso;
 759                                goto new_symbol;
 760                        }
 761
 762                        snprintf(dso_name, sizeof(dso_name),
 763                                 "%s%s", dso->short_name, section_name);
 764
 765                        curr_map = map_groups__find_by_name(kmap->kmaps, map->type, dso_name);
 766                        if (curr_map == NULL) {
 767                                u64 start = sym.st_value;
 768
 769                                if (kmodule)
 770                                        start += map->start + shdr.sh_offset;
 771
 772                                curr_dso = dso__new(dso_name);
 773                                if (curr_dso == NULL)
 774                                        goto out_elf_end;
 775                                curr_dso->kernel = dso->kernel;
 776                                curr_dso->long_name = dso->long_name;
 777                                curr_dso->long_name_len = dso->long_name_len;
 778                                curr_map = map__new2(start, curr_dso,
 779                                                     map->type);
 780                                if (curr_map == NULL) {
 781                                        dso__delete(curr_dso);
 782                                        goto out_elf_end;
 783                                }
 784                                curr_map->map_ip = identity__map_ip;
 785                                curr_map->unmap_ip = identity__map_ip;
 786                                curr_dso->symtab_type = dso->symtab_type;
 787                                map_groups__insert(kmap->kmaps, curr_map);
 788                                dsos__add(&dso->node, curr_dso);
 789                                dso__set_loaded(curr_dso, map->type);
 790                        } else
 791                                curr_dso = curr_map->dso;
 792
 793                        goto new_symbol;
 794                }
 795
 796                if ((used_opd && runtime_ss->adjust_symbols)
 797                                || (!used_opd && syms_ss->adjust_symbols)) {
 798                        pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
 799                                  "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
 800                                  (u64)sym.st_value, (u64)shdr.sh_addr,
 801                                  (u64)shdr.sh_offset);
 802                        sym.st_value -= shdr.sh_addr - shdr.sh_offset;
 803                }
 804                /*
 805                 * We need to figure out if the object was created from C++ sources
 806                 * DWARF DW_compile_unit has this, but we don't always have access
 807                 * to it...
 808                 */
 809                if (symbol_conf.demangle) {
 810                        demangled = bfd_demangle(NULL, elf_name,
 811                                                 DMGL_PARAMS | DMGL_ANSI);
 812                        if (demangled != NULL)
 813                                elf_name = demangled;
 814                }
 815new_symbol:
 816                f = symbol__new(sym.st_value, sym.st_size,
 817                                GELF_ST_BIND(sym.st_info), elf_name);
 818                free(demangled);
 819                if (!f)
 820                        goto out_elf_end;
 821
 822                if (filter && filter(curr_map, f))
 823                        symbol__delete(f);
 824                else {
 825                        symbols__insert(&curr_dso->symbols[curr_map->type], f);
 826                        nr++;
 827                }
 828        }
 829
 830        /*
 831         * For misannotated, zeroed, ASM function sizes.
 832         */
 833        if (nr > 0) {
 834                symbols__fixup_duplicate(&dso->symbols[map->type]);
 835                symbols__fixup_end(&dso->symbols[map->type]);
 836                if (kmap) {
 837                        /*
 838                         * We need to fixup this here too because we create new
 839                         * maps here, for things like vsyscall sections.
 840                         */
 841                        __map_groups__fixup_end(kmap->kmaps, map->type);
 842                }
 843        }
 844        err = nr;
 845out_elf_end:
 846        return err;
 847}
 848
 849void symbol__elf_init(void)
 850{
 851        elf_version(EV_CURRENT);
 852}
 853