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 static bool want_demangle(bool is_kernel_sym)
 210 {
 211         return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
 212 }
 213
 214 static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
 215 {
 216         int demangle_flags = verbose ? (DMGL_PARAMS | DMGL_ANSI) : DMGL_NO_OPTS;
 217         char *demangled = NULL;
 218
 219         /*
 220          * We need to figure out if the object was created from C++ sources
 221          * DWARF DW_compile_unit has this, but we don't always have access
 222          * to it...
 223          */
 224         if (!want_demangle(dso->kernel || kmodule))
 225             return demangled;
 226
 227         demangled = bfd_demangle(NULL, elf_name, demangle_flags);
 228         if (demangled == NULL)
 229                 demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
 230         else if (rust_is_mangled(demangled))
 231                 /*
 232                     * Input to Rust demangling is the BFD-demangled
 233                     * name which it Rust-demangles in place.
 234                     */
 235                 rust_demangle_sym(demangled);
 236
 237         return demangled;
 238 }
 239
 240 #define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
 241         for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
 242              idx < nr_entries; \
 243              ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
 244
 245 #define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
 246         for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
 247              idx < nr_entries; \
 248              ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
 249
 250 /*
 251  * We need to check if we have a .dynsym, so that we can handle the
 252  * .plt, synthesizing its symbols, that aren't on the symtabs (be it
 253  * .dynsym or .symtab).
 254  * And always look at the original dso, not at debuginfo packages, that
 255  * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
 256  */
 257 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss, struct map *map)
 258 {
 259         uint32_t nr_rel_entries, idx;
 260         GElf_Sym sym;
 261         u64 plt_offset;
 262         GElf_Shdr shdr_plt;
 263         struct symbol *f;
 264         GElf_Shdr shdr_rel_plt, shdr_dynsym;
 265         Elf_Data *reldata, *syms, *symstrs;
 266         Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
 267         size_t dynsym_idx;
 268         GElf_Ehdr ehdr;
 269         char sympltname[1024];
 270         Elf *elf;
 271         int nr = 0, symidx, err = 0;
 272
 273         if (!ss->dynsym)
 274                 return 0;
 275
 276         elf = ss->elf;
 277         ehdr = ss->ehdr;
 278
 279         scn_dynsym = ss->dynsym;
 280         shdr_dynsym = ss->dynshdr;
 281         dynsym_idx = ss->dynsym_idx;
 282
 283         if (scn_dynsym == NULL)
 284                 goto out_elf_end;
 285
 286         scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 287                                           ".rela.plt", NULL);
 288         if (scn_plt_rel == NULL) {
 289                 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 290                                                   ".rel.plt", NULL);
 291                 if (scn_plt_rel == NULL)
 292                         goto out_elf_end;
 293         }
 294
 295         err = -1;
 296
 297         if (shdr_rel_plt.sh_link != dynsym_idx)
 298                 goto out_elf_end;
 299
 300         if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
 301                 goto out_elf_end;
 302
 303         /*
 304          * Fetch the relocation section to find the idxes to the GOT
 305          * and the symbols in the .dynsym they refer to.
 306          */
 307         reldata = elf_getdata(scn_plt_rel, NULL);
 308         if (reldata == NULL)
 309                 goto out_elf_end;
 310
 311         syms = elf_getdata(scn_dynsym, NULL);
 312         if (syms == NULL)
 313                 goto out_elf_end;
 314
 315         scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
 316         if (scn_symstrs == NULL)
 317                 goto out_elf_end;
 318
 319         symstrs = elf_getdata(scn_symstrs, NULL);
 320         if (symstrs == NULL)
 321                 goto out_elf_end;
 322
 323         if (symstrs->d_size == 0)
 324                 goto out_elf_end;
 325
 326         nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
 327         plt_offset = shdr_plt.sh_offset;
 328
 329         if (shdr_rel_plt.sh_type == SHT_RELA) {
 330                 GElf_Rela pos_mem, *pos;
 331
 332                 elf_section__for_each_rela(reldata, pos, pos_mem, idx,
 333                                            nr_rel_entries) {
 334                         const char *elf_name = NULL;
 335                         char *demangled = NULL;
 336                         symidx = GELF_R_SYM(pos->r_info);
 337                         plt_offset += shdr_plt.sh_entsize;
 338                         gelf_getsym(syms, symidx, &sym);
 339
 340                         elf_name = elf_sym__name(&sym, symstrs);
 341                         demangled = demangle_sym(dso, 0, elf_name);
 342                         if (demangled != NULL)
 343                                 elf_name = demangled;
 344                         snprintf(sympltname, sizeof(sympltname),
 345                                  "%s@plt", elf_name);
 346                         free(demangled);
 347
 348                         f = symbol__new(plt_offset, shdr_plt.sh_entsize,
 349                                         STB_GLOBAL, sympltname);
 350                         if (!f)
 351                                 goto out_elf_end;
 352
 353                         symbols__insert(&dso->symbols[map->type], f);
 354                         ++nr;
 355                 }
 356         } else if (shdr_rel_plt.sh_type == SHT_REL) {
 357                 GElf_Rel pos_mem, *pos;
 358                 elf_section__for_each_rel(reldata, pos, pos_mem, idx,
 359                                           nr_rel_entries) {
 360                         const char *elf_name = NULL;
 361                         char *demangled = NULL;
 362                         symidx = GELF_R_SYM(pos->r_info);
 363                         plt_offset += shdr_plt.sh_entsize;
 364                         gelf_getsym(syms, symidx, &sym);
 365
 366                         elf_name = elf_sym__name(&sym, symstrs);
 367                         demangled = demangle_sym(dso, 0, elf_name);
 368                         if (demangled != NULL)
 369                                 elf_name = demangled;
 370                         snprintf(sympltname, sizeof(sympltname),
 371                                  "%s@plt", elf_name);
 372                         free(demangled);
 373
 374                         f = symbol__new(plt_offset, shdr_plt.sh_entsize,
 375                                         STB_GLOBAL, sympltname);
 376                         if (!f)
 377                                 goto out_elf_end;
 378
 379                         symbols__insert(&dso->symbols[map->type], f);
 380                         ++nr;
 381                 }
 382         }
 383
 384         err = 0;
 385 out_elf_end:
 386         if (err == 0)
 387                 return nr;
 388         pr_debug("%s: problems reading %s PLT info.\n",
 389                  __func__, dso->long_name);
 390         return 0;
 391 }
 392
 393 /*
 394  * Align offset to 4 bytes as needed for note name and descriptor data.
 395  */
 396 #define NOTE_ALIGN(n) (((n) + 3) & -4U)
 397
 398 static int elf_read_build_id(Elf *elf, void *bf, size_t size)
 399 {
 400         int err = -1;
 401         GElf_Ehdr ehdr;
 402         GElf_Shdr shdr;
 403         Elf_Data *data;
 404         Elf_Scn *sec;
 405         Elf_Kind ek;
 406         void *ptr;
 407
 408         if (size < BUILD_ID_SIZE)
 409                 goto out;
 410
 411         ek = elf_kind(elf);
 412         if (ek != ELF_K_ELF)
 413                 goto out;
 414
 415         if (gelf_getehdr(elf, &ehdr) == NULL) {
 416                 pr_err("%s: cannot get elf header.\n", __func__);
 417                 goto out;
 418         }
 419
 420         /*
 421          * Check following sections for notes:
 422          *   '.note.gnu.build-id'
 423          *   '.notes'
 424          *   '.note' (VDSO specific)
 425          */
 426         do {
 427                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 428                                           ".note.gnu.build-id", NULL);
 429                 if (sec)
 430                         break;
 431
 432                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 433                                           ".notes", NULL);
 434                 if (sec)
 435                         break;
 436
 437                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 438                                           ".note", NULL);
 439                 if (sec)
 440                         break;
 441
 442                 return err;
 443
 444         } while (0);
 445
 446         data = elf_getdata(sec, NULL);
 447         if (data == NULL)
 448                 goto out;
 449
 450         ptr = data->d_buf;
 451         while (ptr < (data->d_buf + data->d_size)) {
 452                 GElf_Nhdr *nhdr = ptr;
 453                 size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
 454                        descsz = NOTE_ALIGN(nhdr->n_descsz);
 455                 const char *name;
 456
 457                 ptr += sizeof(*nhdr);
 458                 name = ptr;
 459                 ptr += namesz;
 460                 if (nhdr->n_type == NT_GNU_BUILD_ID &&
 461                     nhdr->n_namesz == sizeof("GNU")) {
 462                         if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
 463                                 size_t sz = min(size, descsz);
 464                                 memcpy(bf, ptr, sz);
 465                                 memset(bf + sz, 0, size - sz);
 466                                 err = descsz;
 467                                 break;
 468                         }
 469                 }
 470                 ptr += descsz;
 471         }
 472
 473 out:
 474         return err;
 475 }
 476
 477 int filename__read_build_id(const char *filename, void *bf, size_t size)
 478 {
 479         int fd, err = -1;
 480         Elf *elf;
 481
 482         if (size < BUILD_ID_SIZE)
 483                 goto out;
 484
 485         fd = open(filename, O_RDONLY);
 486         if (fd < 0)
 487                 goto out;
 488
 489         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 490         if (elf == NULL) {
 491                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 492                 goto out_close;
 493         }
 494
 495         err = elf_read_build_id(elf, bf, size);
 496
 497         elf_end(elf);
 498 out_close:
 499         close(fd);
 500 out:
 501         return err;
 502 }
 503
 504 int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
 505 {
 506         int fd, err = -1;
 507
 508         if (size < BUILD_ID_SIZE)
 509                 goto out;
 510
 511         fd = open(filename, O_RDONLY);
 512         if (fd < 0)
 513                 goto out;
 514
 515         while (1) {
 516                 char bf[BUFSIZ];
 517                 GElf_Nhdr nhdr;
 518                 size_t namesz, descsz;
 519
 520                 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
 521                         break;
 522
 523                 namesz = NOTE_ALIGN(nhdr.n_namesz);
 524                 descsz = NOTE_ALIGN(nhdr.n_descsz);
 525                 if (nhdr.n_type == NT_GNU_BUILD_ID &&
 526                     nhdr.n_namesz == sizeof("GNU")) {
 527                         if (read(fd, bf, namesz) != (ssize_t)namesz)
 528                                 break;
 529                         if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
 530                                 size_t sz = min(descsz, size);
 531                                 if (read(fd, build_id, sz) == (ssize_t)sz) {
 532                                         memset(build_id + sz, 0, size - sz);
 533                                         err = 0;
 534                                         break;
 535                                 }
 536                         } else if (read(fd, bf, descsz) != (ssize_t)descsz)
 537                                 break;
 538                 } else {
 539                         int n = namesz + descsz;
 540
 541                         if (n > (int)sizeof(bf)) {
 542                                 n = sizeof(bf);
 543                                 pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n",
 544                                          __func__, filename, nhdr.n_namesz, nhdr.n_descsz);
 545                         }
 546                         if (read(fd, bf, n) != n)
 547                                 break;
 548                 }
 549         }
 550         close(fd);
 551 out:
 552         return err;
 553 }
 554
 555 int filename__read_debuglink(const char *filename, char *debuglink,
 556                              size_t size)
 557 {
 558         int fd, err = -1;
 559         Elf *elf;
 560         GElf_Ehdr ehdr;
 561         GElf_Shdr shdr;
 562         Elf_Data *data;
 563         Elf_Scn *sec;
 564         Elf_Kind ek;
 565
 566         fd = open(filename, O_RDONLY);
 567         if (fd < 0)
 568                 goto out;
 569
 570         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 571         if (elf == NULL) {
 572                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 573                 goto out_close;
 574         }
 575
 576         ek = elf_kind(elf);
 577         if (ek != ELF_K_ELF)
 578                 goto out_elf_end;
 579
 580         if (gelf_getehdr(elf, &ehdr) == NULL) {
 581                 pr_err("%s: cannot get elf header.\n", __func__);
 582                 goto out_elf_end;
 583         }
 584
 585         sec = elf_section_by_name(elf, &ehdr, &shdr,
 586                                   ".gnu_debuglink", NULL);
 587         if (sec == NULL)
 588                 goto out_elf_end;
 589
 590         data = elf_getdata(sec, NULL);
 591         if (data == NULL)
 592                 goto out_elf_end;
 593
 594         /* the start of this section is a zero-terminated string */
 595         strncpy(debuglink, data->d_buf, size);
 596
 597         err = 0;
 598
 599 out_elf_end:
 600         elf_end(elf);
 601 out_close:
 602         close(fd);
 603 out:
 604         return err;
 605 }
 606
 607 static int dso__swap_init(struct dso *dso, unsigned char eidata)
 608 {
 609         static unsigned int const endian = 1;
 610
 611         dso->needs_swap = DSO_SWAP__NO;
 612
 613         switch (eidata) {
 614         case ELFDATA2LSB:
 615                 /* We are big endian, DSO is little endian. */
 616                 if (*(unsigned char const *)&endian != 1)
 617                         dso->needs_swap = DSO_SWAP__YES;
 618                 break;
 619
 620         case ELFDATA2MSB:
 621                 /* We are little endian, DSO is big endian. */
 622                 if (*(unsigned char const *)&endian != 0)
 623                         dso->needs_swap = DSO_SWAP__YES;
 624                 break;
 625
 626         default:
 627                 pr_err("unrecognized DSO data encoding %d\n", eidata);
 628                 return -EINVAL;
 629         }
 630
 631         return 0;
 632 }
 633
 634 static int decompress_kmodule(struct dso *dso, const char *name,
 635                               enum dso_binary_type type)
 636 {
 637         int fd = -1;
 638         char tmpbuf[] = "/tmp/perf-kmod-XXXXXX";
 639         struct kmod_path m;
 640
 641         if (type != DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP &&
 642             type != DSO_BINARY_TYPE__GUEST_KMODULE_COMP &&
 643             type != DSO_BINARY_TYPE__BUILD_ID_CACHE)
 644                 return -1;
 645
 646         if (type == DSO_BINARY_TYPE__BUILD_ID_CACHE)
 647                 name = dso->long_name;
 648
 649         if (kmod_path__parse_ext(&m, name) || !m.comp)
 650                 return -1;
 651
 652         fd = mkstemp(tmpbuf);
 653         if (fd < 0) {
 654                 dso->load_errno = errno;
 655                 goto out;
 656         }
 657
 658         if (!decompress_to_file(m.ext, name, fd)) {
 659                 dso->load_errno = DSO_LOAD_ERRNO__DECOMPRESSION_FAILURE;
 660                 close(fd);
 661                 fd = -1;
 662         }
 663
 664         unlink(tmpbuf);
 665
 666 out:
 667         free(m.ext);
 668         return fd;
 669 }
 670
 671 bool symsrc__possibly_runtime(struct symsrc *ss)
 672 {
 673         return ss->dynsym || ss->opdsec;
 674 }
 675
 676 bool symsrc__has_symtab(struct symsrc *ss)
 677 {
 678         return ss->symtab != NULL;
 679 }
 680
 681 void symsrc__destroy(struct symsrc *ss)
 682 {
 683         zfree(&ss->name);
 684         elf_end(ss->elf);
 685         close(ss->fd);
 686 }
 687
 688 bool __weak elf__needs_adjust_symbols(GElf_Ehdr ehdr)
 689 {
 690         return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL;
 691 }
 692
 693 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
 694                  enum dso_binary_type type)
 695 {
 696         int err = -1;
 697         GElf_Ehdr ehdr;
 698         Elf *elf;
 699         int fd;
 700
 701         if (dso__needs_decompress(dso)) {
 702                 fd = decompress_kmodule(dso, name, type);
 703                 if (fd < 0)
 704                         return -1;
 705         } else {
 706                 fd = open(name, O_RDONLY);
 707                 if (fd < 0) {
 708                         dso->load_errno = errno;
 709                         return -1;
 710                 }
 711         }
 712
 713         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 714         if (elf == NULL) {
 715                 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
 716                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 717                 goto out_close;
 718         }
 719
 720         if (gelf_getehdr(elf, &ehdr) == NULL) {
 721                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 722                 pr_debug("%s: cannot get elf header.\n", __func__);
 723                 goto out_elf_end;
 724         }
 725
 726         if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
 727                 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
 728                 goto out_elf_end;
 729         }
 730
 731         /* Always reject images with a mismatched build-id: */
 732         if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) {
 733                 u8 build_id[BUILD_ID_SIZE];
 734
 735                 if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) {
 736                         dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
 737                         goto out_elf_end;
 738                 }
 739
 740                 if (!dso__build_id_equal(dso, build_id)) {
 741                         pr_debug("%s: build id mismatch for %s.\n", __func__, name);
 742                         dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
 743                         goto out_elf_end;
 744                 }
 745         }
 746
 747         ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
 748
 749         ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
 750                         NULL);
 751         if (ss->symshdr.sh_type != SHT_SYMTAB)
 752                 ss->symtab = NULL;
 753
 754         ss->dynsym_idx = 0;
 755         ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
 756                         &ss->dynsym_idx);
 757         if (ss->dynshdr.sh_type != SHT_DYNSYM)
 758                 ss->dynsym = NULL;
 759
 760         ss->opdidx = 0;
 761         ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
 762                         &ss->opdidx);
 763         if (ss->opdshdr.sh_type != SHT_PROGBITS)
 764                 ss->opdsec = NULL;
 765
 766         if (dso->kernel == DSO_TYPE_USER)
 767                 ss->adjust_symbols = true;
 768         else
 769                 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
 770
 771         ss->name   = strdup(name);
 772         if (!ss->name) {
 773                 dso->load_errno = errno;
 774                 goto out_elf_end;
 775         }
 776
 777         ss->elf    = elf;
 778         ss->fd     = fd;
 779         ss->ehdr   = ehdr;
 780         ss->type   = type;
 781
 782         return 0;
 783
 784 out_elf_end:
 785         elf_end(elf);
 786 out_close:
 787         close(fd);
 788         return err;
 789 }
 790
 791 /**
 792  * ref_reloc_sym_not_found - has kernel relocation symbol been found.
 793  * @kmap: kernel maps and relocation reference symbol
 794  *
 795  * This function returns %true if we are dealing with the kernel maps and the
 796  * relocation reference symbol has not yet been found.  Otherwise %false is
 797  * returned.
 798  */
 799 static bool ref_reloc_sym_not_found(struct kmap *kmap)
 800 {
 801         return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
 802                !kmap->ref_reloc_sym->unrelocated_addr;
 803 }
 804
 805 /**
 806  * ref_reloc - kernel relocation offset.
 807  * @kmap: kernel maps and relocation reference symbol
 808  *
 809  * This function returns the offset of kernel addresses as determined by using
 810  * the relocation reference symbol i.e. if the kernel has not been relocated
 811  * then the return value is zero.
 812  */
 813 static u64 ref_reloc(struct kmap *kmap)
 814 {
 815         if (kmap && kmap->ref_reloc_sym &&
 816             kmap->ref_reloc_sym->unrelocated_addr)
 817                 return kmap->ref_reloc_sym->addr -
 818                        kmap->ref_reloc_sym->unrelocated_addr;
 819         return 0;
 820 }
 821
 822 void __weak arch__sym_update(struct symbol *s __maybe_unused,
 823                 GElf_Sym *sym __maybe_unused) { }
 824
 825 int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
 826                   struct symsrc *runtime_ss, int kmodule)
 827 {
 828         struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
 829         struct map_groups *kmaps = kmap ? map__kmaps(map) : NULL;
 830         struct map *curr_map = map;
 831         struct dso *curr_dso = dso;
 832         Elf_Data *symstrs, *secstrs;
 833         uint32_t nr_syms;
 834         int err = -1;
 835         uint32_t idx;
 836         GElf_Ehdr ehdr;
 837         GElf_Shdr shdr;
 838         GElf_Shdr tshdr;
 839         Elf_Data *syms, *opddata = NULL;
 840         GElf_Sym sym;
 841         Elf_Scn *sec, *sec_strndx;
 842         Elf *elf;
 843         int nr = 0;
 844         bool remap_kernel = false, adjust_kernel_syms = false;
 845
 846         if (kmap && !kmaps)
 847                 return -1;
 848
 849         dso->symtab_type = syms_ss->type;
 850         dso->is_64_bit = syms_ss->is_64_bit;
 851         dso->rel = syms_ss->ehdr.e_type == ET_REL;
 852
 853         /*
 854          * Modules may already have symbols from kallsyms, but those symbols
 855          * have the wrong values for the dso maps, so remove them.
 856          */
 857         if (kmodule && syms_ss->symtab)
 858                 symbols__delete(&dso->symbols[map->type]);
 859
 860         if (!syms_ss->symtab) {
 861                 /*
 862                  * If the vmlinux is stripped, fail so we will fall back
 863                  * to using kallsyms. The vmlinux runtime symbols aren't
 864                  * of much use.
 865                  */
 866                 if (dso->kernel)
 867                         goto out_elf_end;
 868
 869                 syms_ss->symtab  = syms_ss->dynsym;
 870                 syms_ss->symshdr = syms_ss->dynshdr;
 871         }
 872
 873         elf = syms_ss->elf;
 874         ehdr = syms_ss->ehdr;
 875         sec = syms_ss->symtab;
 876         shdr = syms_ss->symshdr;
 877
 878         if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
 879                                 ".text", NULL))
 880                 dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
 881
 882         if (runtime_ss->opdsec)
 883                 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
 884
 885         syms = elf_getdata(sec, NULL);
 886         if (syms == NULL)
 887                 goto out_elf_end;
 888
 889         sec = elf_getscn(elf, shdr.sh_link);
 890         if (sec == NULL)
 891                 goto out_elf_end;
 892
 893         symstrs = elf_getdata(sec, NULL);
 894         if (symstrs == NULL)
 895                 goto out_elf_end;
 896
 897         sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
 898         if (sec_strndx == NULL)
 899                 goto out_elf_end;
 900
 901         secstrs = elf_getdata(sec_strndx, NULL);
 902         if (secstrs == NULL)
 903                 goto out_elf_end;
 904
 905         nr_syms = shdr.sh_size / shdr.sh_entsize;
 906
 907         memset(&sym, 0, sizeof(sym));
 908
 909         /*
 910          * The kernel relocation symbol is needed in advance in order to adjust
 911          * kernel maps correctly.
 912          */
 913         if (ref_reloc_sym_not_found(kmap)) {
 914                 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
 915                         const char *elf_name = elf_sym__name(&sym, symstrs);
 916
 917                         if (strcmp(elf_name, kmap->ref_reloc_sym->name))
 918                                 continue;
 919                         kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
 920                         map->reloc = kmap->ref_reloc_sym->addr -
 921                                      kmap->ref_reloc_sym->unrelocated_addr;
 922                         break;
 923                 }
 924         }
 925
 926         /*
 927          * Handle any relocation of vdso necessary because older kernels
 928          * attempted to prelink vdso to its virtual address.
 929          */
 930         if (dso__is_vdso(dso))
 931                 map->reloc = map->start - dso->text_offset;
 932
 933         dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
 934         /*
 935          * Initial kernel and module mappings do not map to the dso.  For
 936          * function mappings, flag the fixups.
 937          */
 938         if (map->type == MAP__FUNCTION && (dso->kernel || kmodule)) {
 939                 remap_kernel = true;
 940                 adjust_kernel_syms = dso->adjust_symbols;
 941         }
 942         elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
 943                 struct symbol *f;
 944                 const char *elf_name = elf_sym__name(&sym, symstrs);
 945                 char *demangled = NULL;
 946                 int is_label = elf_sym__is_label(&sym);
 947                 const char *section_name;
 948                 bool used_opd = false;
 949
 950                 if (!is_label && !elf_sym__is_a(&sym, map->type))
 951                         continue;
 952
 953                 /* Reject ARM ELF "mapping symbols": these aren't unique and
 954                  * don't identify functions, so will confuse the profile
 955                  * output: */
 956                 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
 957                         if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
 958                             && (elf_name[2] == '\0' || elf_name[2] == '.'))
 959                                 continue;
 960                 }
 961
 962                 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
 963                         u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
 964                         u64 *opd = opddata->d_buf + offset;
 965                         sym.st_value = DSO__SWAP(dso, u64, *opd);
 966                         sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
 967                                         sym.st_value);
 968                         used_opd = true;
 969                 }
 970                 /*
 971                  * When loading symbols in a data mapping, ABS symbols (which
 972                  * has a value of SHN_ABS in its st_shndx) failed at
 973                  * elf_getscn().  And it marks the loading as a failure so
 974                  * already loaded symbols cannot be fixed up.
 975                  *
 976                  * I'm not sure what should be done. Just ignore them for now.
 977                  * - Namhyung Kim
 978                  */
 979                 if (sym.st_shndx == SHN_ABS)
 980                         continue;
 981
 982                 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
 983                 if (!sec)
 984                         goto out_elf_end;
 985
 986                 gelf_getshdr(sec, &shdr);
 987
 988                 if (is_label && !elf_sec__is_a(&shdr, secstrs, map->type))
 989                         continue;
 990
 991                 section_name = elf_sec__name(&shdr, secstrs);
 992
 993                 /* On ARM, symbols for thumb functions have 1 added to
 994                  * the symbol address as a flag - remove it */
 995                 if ((ehdr.e_machine == EM_ARM) &&
 996                     (map->type == MAP__FUNCTION) &&
 997                     (sym.st_value & 1))
 998                         --sym.st_value;
 999
1000                 if (dso->kernel || kmodule) {
1001                         char dso_name[PATH_MAX];
1002
1003                         /* Adjust symbol to map to file offset */
1004                         if (adjust_kernel_syms)
1005                                 sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1006
1007                         if (strcmp(section_name,
1008                                    (curr_dso->short_name +
1009                                     dso->short_name_len)) == 0)
1010                                 goto new_symbol;
1011
1012                         if (strcmp(section_name, ".text") == 0) {
1013                                 /*
1014                                  * The initial kernel mapping is based on
1015                                  * kallsyms and identity maps.  Overwrite it to
1016                                  * map to the kernel dso.
1017                                  */
1018                                 if (remap_kernel && dso->kernel) {
1019                                         remap_kernel = false;
1020                                         map->start = shdr.sh_addr +
1021                                                      ref_reloc(kmap);
1022                                         map->end = map->start + shdr.sh_size;
1023                                         map->pgoff = shdr.sh_offset;
1024                                         map->map_ip = map__map_ip;
1025                                         map->unmap_ip = map__unmap_ip;
1026                                         /* Ensure maps are correctly ordered */
1027                                         if (kmaps) {
1028                                                 map__get(map);
1029                                                 map_groups__remove(kmaps, map);
1030                                                 map_groups__insert(kmaps, map);
1031                                                 map__put(map);
1032                                         }
1033                                 }
1034
1035                                 /*
1036                                  * The initial module mapping is based on
1037                                  * /proc/modules mapped to offset zero.
1038                                  * Overwrite it to map to the module dso.
1039                                  */
1040                                 if (remap_kernel && kmodule) {
1041                                         remap_kernel = false;
1042                                         map->pgoff = shdr.sh_offset;
1043                                 }
1044
1045                                 curr_map = map;
1046                                 curr_dso = dso;
1047                                 goto new_symbol;
1048                         }
1049
1050                         if (!kmap)
1051                                 goto new_symbol;
1052
1053                         snprintf(dso_name, sizeof(dso_name),
1054                                  "%s%s", dso->short_name, section_name);
1055
1056                         curr_map = map_groups__find_by_name(kmaps, map->type, dso_name);
1057                         if (curr_map == NULL) {
1058                                 u64 start = sym.st_value;
1059
1060                                 if (kmodule)
1061                                         start += map->start + shdr.sh_offset;
1062
1063                                 curr_dso = dso__new(dso_name);
1064                                 if (curr_dso == NULL)
1065                                         goto out_elf_end;
1066                                 curr_dso->kernel = dso->kernel;
1067                                 curr_dso->long_name = dso->long_name;
1068                                 curr_dso->long_name_len = dso->long_name_len;
1069                                 curr_map = map__new2(start, curr_dso,
1070                                                      map->type);
1071                                 dso__put(curr_dso);
1072                                 if (curr_map == NULL) {
1073                                         goto out_elf_end;
1074                                 }
1075                                 if (adjust_kernel_syms) {
1076                                         curr_map->start = shdr.sh_addr +
1077                                                           ref_reloc(kmap);
1078                                         curr_map->end = curr_map->start +
1079                                                         shdr.sh_size;
1080                                         curr_map->pgoff = shdr.sh_offset;
1081                                 } else {
1082                                         curr_map->map_ip = identity__map_ip;
1083                                         curr_map->unmap_ip = identity__map_ip;
1084                                 }
1085                                 curr_dso->symtab_type = dso->symtab_type;
1086                                 map_groups__insert(kmaps, curr_map);
1087                                 /*
1088                                  * Add it before we drop the referece to curr_map,
1089                                  * i.e. while we still are sure to have a reference
1090                                  * to this DSO via curr_map->dso.
1091                                  */
1092                                 dsos__add(&map->groups->machine->dsos, curr_dso);
1093                                 /* kmaps already got it */
1094                                 map__put(curr_map);
1095                                 dso__set_loaded(curr_dso, map->type);
1096                         } else
1097                                 curr_dso = curr_map->dso;
1098
1099                         goto new_symbol;
1100                 }
1101
1102                 if ((used_opd && runtime_ss->adjust_symbols)
1103                                 || (!used_opd && syms_ss->adjust_symbols)) {
1104                         pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1105                                   "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
1106                                   (u64)sym.st_value, (u64)shdr.sh_addr,
1107                                   (u64)shdr.sh_offset);
1108                         sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1109                 }
1110 new_symbol:
1111                 demangled = demangle_sym(dso, kmodule, elf_name);
1112                 if (demangled != NULL)
1113                         elf_name = demangled;
1114
1115                 f = symbol__new(sym.st_value, sym.st_size,
1116                                 GELF_ST_BIND(sym.st_info), elf_name);
1117                 free(demangled);
1118                 if (!f)
1119                         goto out_elf_end;
1120
1121                 arch__sym_update(f, &sym);
1122
1123                 __symbols__insert(&curr_dso->symbols[curr_map->type], f, dso->kernel);
1124                 nr++;
1125         }
1126
1127         /*
1128          * For misannotated, zeroed, ASM function sizes.
1129          */
1130         if (nr > 0) {
1131                 symbols__fixup_end(&dso->symbols[map->type]);
1132                 symbols__fixup_duplicate(&dso->symbols[map->type]);
1133                 if (kmap) {
1134                         /*
1135                          * We need to fixup this here too because we create new
1136                          * maps here, for things like vsyscall sections.
1137                          */
1138                         __map_groups__fixup_end(kmaps, map->type);
1139                 }
1140         }
1141         err = nr;
1142 out_elf_end:
1143         return err;
1144 }
1145
1146 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1147 {
1148         GElf_Phdr phdr;
1149         size_t i, phdrnum;
1150         int err;
1151         u64 sz;
1152
1153         if (elf_getphdrnum(elf, &phdrnum))
1154                 return -1;
1155
1156         for (i = 0; i < phdrnum; i++) {
1157                 if (gelf_getphdr(elf, i, &phdr) == NULL)
1158                         return -1;
1159                 if (phdr.p_type != PT_LOAD)
1160                         continue;
1161                 if (exe) {
1162                         if (!(phdr.p_flags & PF_X))
1163                                 continue;
1164                 } else {
1165                         if (!(phdr.p_flags & PF_R))
1166                                 continue;
1167                 }
1168                 sz = min(phdr.p_memsz, phdr.p_filesz);
1169                 if (!sz)
1170                         continue;
1171                 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1172                 if (err)
1173                         return err;
1174         }
1175         return 0;
1176 }
1177
1178 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1179                     bool *is_64_bit)
1180 {
1181         int err;
1182         Elf *elf;
1183
1184         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1185         if (elf == NULL)
1186                 return -1;
1187
1188         if (is_64_bit)
1189                 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1190
1191         err = elf_read_maps(elf, exe, mapfn, data);
1192
1193         elf_end(elf);
1194         return err;
1195 }
1196
1197 enum dso_type dso__type_fd(int fd)
1198 {
1199         enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1200         GElf_Ehdr ehdr;
1201         Elf_Kind ek;
1202         Elf *elf;
1203
1204         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1205         if (elf == NULL)
1206                 goto out;
1207
1208         ek = elf_kind(elf);
1209         if (ek != ELF_K_ELF)
1210                 goto out_end;
1211
1212         if (gelf_getclass(elf) == ELFCLASS64) {
1213                 dso_type = DSO__TYPE_64BIT;
1214                 goto out_end;
1215         }
1216
1217         if (gelf_getehdr(elf, &ehdr) == NULL)
1218                 goto out_end;
1219
1220         if (ehdr.e_machine == EM_X86_64)
1221                 dso_type = DSO__TYPE_X32BIT;
1222         else
1223                 dso_type = DSO__TYPE_32BIT;
1224 out_end:
1225         elf_end(elf);
1226 out:
1227         return dso_type;
1228 }
1229
1230 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1231 {
1232         ssize_t r;
1233         size_t n;
1234         int err = -1;
1235         char *buf = malloc(page_size);
1236
1237         if (buf == NULL)
1238                 return -1;
1239
1240         if (lseek(to, to_offs, SEEK_SET) != to_offs)
1241                 goto out;
1242
1243         if (lseek(from, from_offs, SEEK_SET) != from_offs)
1244                 goto out;
1245
1246         while (len) {
1247                 n = page_size;
1248                 if (len < n)
1249                         n = len;
1250                 /* Use read because mmap won't work on proc files */
1251                 r = read(from, buf, n);
1252                 if (r < 0)
1253                         goto out;
1254                 if (!r)
1255                         break;
1256                 n = r;
1257                 r = write(to, buf, n);
1258                 if (r < 0)
1259                         goto out;
1260                 if ((size_t)r != n)
1261                         goto out;
1262                 len -= n;
1263         }
1264
1265         err = 0;
1266 out:
1267         free(buf);
1268         return err;
1269 }
1270
1271 struct kcore {
1272         int fd;
1273         int elfclass;
1274         Elf *elf;
1275         GElf_Ehdr ehdr;
1276 };
1277
1278 static int kcore__open(struct kcore *kcore, const char *filename)
1279 {
1280         GElf_Ehdr *ehdr;
1281
1282         kcore->fd = open(filename, O_RDONLY);
1283         if (kcore->fd == -1)
1284                 return -1;
1285
1286         kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1287         if (!kcore->elf)
1288                 goto out_close;
1289
1290         kcore->elfclass = gelf_getclass(kcore->elf);
1291         if (kcore->elfclass == ELFCLASSNONE)
1292                 goto out_end;
1293
1294         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1295         if (!ehdr)
1296                 goto out_end;
1297
1298         return 0;
1299
1300 out_end:
1301         elf_end(kcore->elf);
1302 out_close:
1303         close(kcore->fd);
1304         return -1;
1305 }
1306
1307 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1308                        bool temp)
1309 {
1310         kcore->elfclass = elfclass;
1311
1312         if (temp)
1313                 kcore->fd = mkstemp(filename);
1314         else
1315                 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1316         if (kcore->fd == -1)
1317                 return -1;
1318
1319         kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1320         if (!kcore->elf)
1321                 goto out_close;
1322
1323         if (!gelf_newehdr(kcore->elf, elfclass))
1324                 goto out_end;
1325
1326         memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
1327
1328         return 0;
1329
1330 out_end:
1331         elf_end(kcore->elf);
1332 out_close:
1333         close(kcore->fd);
1334         unlink(filename);
1335         return -1;
1336 }
1337
1338 static void kcore__close(struct kcore *kcore)
1339 {
1340         elf_end(kcore->elf);
1341         close(kcore->fd);
1342 }
1343
1344 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1345 {
1346         GElf_Ehdr *ehdr = &to->ehdr;
1347         GElf_Ehdr *kehdr = &from->ehdr;
1348
1349         memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1350         ehdr->e_type      = kehdr->e_type;
1351         ehdr->e_machine   = kehdr->e_machine;
1352         ehdr->e_version   = kehdr->e_version;
1353         ehdr->e_entry     = 0;
1354         ehdr->e_shoff     = 0;
1355         ehdr->e_flags     = kehdr->e_flags;
1356         ehdr->e_phnum     = count;
1357         ehdr->e_shentsize = 0;
1358         ehdr->e_shnum     = 0;
1359         ehdr->e_shstrndx  = 0;
1360
1361         if (from->elfclass == ELFCLASS32) {
1362                 ehdr->e_phoff     = sizeof(Elf32_Ehdr);
1363                 ehdr->e_ehsize    = sizeof(Elf32_Ehdr);
1364                 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1365         } else {
1366                 ehdr->e_phoff     = sizeof(Elf64_Ehdr);
1367                 ehdr->e_ehsize    = sizeof(Elf64_Ehdr);
1368                 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1369         }
1370
1371         if (!gelf_update_ehdr(to->elf, ehdr))
1372                 return -1;
1373
1374         if (!gelf_newphdr(to->elf, count))
1375                 return -1;
1376
1377         return 0;
1378 }
1379
1380 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1381                            u64 addr, u64 len)
1382 {
1383         GElf_Phdr phdr = {
1384                 .p_type         = PT_LOAD,
1385                 .p_flags        = PF_R | PF_W | PF_X,
1386                 .p_offset       = offset,
1387                 .p_vaddr        = addr,
1388                 .p_paddr        = 0,
1389                 .p_filesz       = len,
1390                 .p_memsz        = len,
1391                 .p_align        = page_size,
1392         };
1393
1394         if (!gelf_update_phdr(kcore->elf, idx, &phdr))
1395                 return -1;
1396
1397         return 0;
1398 }
1399
1400 static off_t kcore__write(struct kcore *kcore)
1401 {
1402         return elf_update(kcore->elf, ELF_C_WRITE);
1403 }
1404
1405 struct phdr_data {
1406         off_t offset;
1407         u64 addr;
1408         u64 len;
1409 };
1410
1411 struct kcore_copy_info {
1412         u64 stext;
1413         u64 etext;
1414         u64 first_symbol;
1415         u64 last_symbol;
1416         u64 first_module;
1417         u64 last_module_symbol;
1418         struct phdr_data kernel_map;
1419         struct phdr_data modules_map;
1420 };
1421
1422 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1423                                         u64 start)
1424 {
1425         struct kcore_copy_info *kci = arg;
1426
1427         if (!symbol_type__is_a(type, MAP__FUNCTION))
1428                 return 0;
1429
1430         if (strchr(name, '[')) {
1431                 if (start > kci->last_module_symbol)
1432                         kci->last_module_symbol = start;
1433                 return 0;
1434         }
1435
1436         if (!kci->first_symbol || start < kci->first_symbol)
1437                 kci->first_symbol = start;
1438
1439         if (!kci->last_symbol || start > kci->last_symbol)
1440                 kci->last_symbol = start;
1441
1442         if (!strcmp(name, "_stext")) {
1443                 kci->stext = start;
1444                 return 0;
1445         }
1446
1447         if (!strcmp(name, "_etext")) {
1448                 kci->etext = start;
1449                 return 0;
1450         }
1451
1452         return 0;
1453 }
1454
1455 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1456                                       const char *dir)
1457 {
1458         char kallsyms_filename[PATH_MAX];
1459
1460         scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1461
1462         if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1463                 return -1;
1464
1465         if (kallsyms__parse(kallsyms_filename, kci,
1466                             kcore_copy__process_kallsyms) < 0)
1467                 return -1;
1468
1469         return 0;
1470 }
1471
1472 static int kcore_copy__process_modules(void *arg,
1473                                        const char *name __maybe_unused,
1474                                        u64 start)
1475 {
1476         struct kcore_copy_info *kci = arg;
1477
1478         if (!kci->first_module || start < kci->first_module)
1479                 kci->first_module = start;
1480
1481         return 0;
1482 }
1483
1484 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1485                                      const char *dir)
1486 {
1487         char modules_filename[PATH_MAX];
1488
1489         scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1490
1491         if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1492                 return -1;
1493
1494         if (modules__parse(modules_filename, kci,
1495                            kcore_copy__process_modules) < 0)
1496                 return -1;
1497
1498         return 0;
1499 }
1500
1501 static void kcore_copy__map(struct phdr_data *p, u64 start, u64 end, u64 pgoff,
1502                             u64 s, u64 e)
1503 {
1504         if (p->addr || s < start || s >= end)
1505                 return;
1506
1507         p->addr = s;
1508         p->offset = (s - start) + pgoff;
1509         p->len = e < end ? e - s : end - s;
1510 }
1511
1512 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1513 {
1514         struct kcore_copy_info *kci = data;
1515         u64 end = start + len;
1516
1517         kcore_copy__map(&kci->kernel_map, start, end, pgoff, kci->stext,
1518                         kci->etext);
1519
1520         kcore_copy__map(&kci->modules_map, start, end, pgoff, kci->first_module,
1521                         kci->last_module_symbol);
1522
1523         return 0;
1524 }
1525
1526 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1527 {
1528         if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1529                 return -1;
1530
1531         return 0;
1532 }
1533
1534 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1535                                  Elf *elf)
1536 {
1537         if (kcore_copy__parse_kallsyms(kci, dir))
1538                 return -1;
1539
1540         if (kcore_copy__parse_modules(kci, dir))
1541                 return -1;
1542
1543         if (kci->stext)
1544                 kci->stext = round_down(kci->stext, page_size);
1545         else
1546                 kci->stext = round_down(kci->first_symbol, page_size);
1547
1548         if (kci->etext) {
1549                 kci->etext = round_up(kci->etext, page_size);
1550         } else if (kci->last_symbol) {
1551                 kci->etext = round_up(kci->last_symbol, page_size);
1552                 kci->etext += page_size;
1553         }
1554
1555         kci->first_module = round_down(kci->first_module, page_size);
1556
1557         if (kci->last_module_symbol) {
1558                 kci->last_module_symbol = round_up(kci->last_module_symbol,
1559                                                    page_size);
1560                 kci->last_module_symbol += page_size;
1561         }
1562
1563         if (!kci->stext || !kci->etext)
1564                 return -1;
1565
1566         if (kci->first_module && !kci->last_module_symbol)
1567                 return -1;
1568
1569         return kcore_copy__read_maps(kci, elf);
1570 }
1571
1572 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1573                                  const char *name)
1574 {
1575         char from_filename[PATH_MAX];
1576         char to_filename[PATH_MAX];
1577
1578         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1579         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1580
1581         return copyfile_mode(from_filename, to_filename, 0400);
1582 }
1583
1584 static int kcore_copy__unlink(const char *dir, const char *name)
1585 {
1586         char filename[PATH_MAX];
1587
1588         scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1589
1590         return unlink(filename);
1591 }
1592
1593 static int kcore_copy__compare_fds(int from, int to)
1594 {
1595         char *buf_from;
1596         char *buf_to;
1597         ssize_t ret;
1598         size_t len;
1599         int err = -1;
1600
1601         buf_from = malloc(page_size);
1602         buf_to = malloc(page_size);
1603         if (!buf_from || !buf_to)
1604                 goto out;
1605
1606         while (1) {
1607                 /* Use read because mmap won't work on proc files */
1608                 ret = read(from, buf_from, page_size);
1609                 if (ret < 0)
1610                         goto out;
1611
1612                 if (!ret)
1613                         break;
1614
1615                 len = ret;
1616
1617                 if (readn(to, buf_to, len) != (int)len)
1618                         goto out;
1619
1620                 if (memcmp(buf_from, buf_to, len))
1621                         goto out;
1622         }
1623
1624         err = 0;
1625 out:
1626         free(buf_to);
1627         free(buf_from);
1628         return err;
1629 }
1630
1631 static int kcore_copy__compare_files(const char *from_filename,
1632                                      const char *to_filename)
1633 {
1634         int from, to, err = -1;
1635
1636         from = open(from_filename, O_RDONLY);
1637         if (from < 0)
1638                 return -1;
1639
1640         to = open(to_filename, O_RDONLY);
1641         if (to < 0)
1642                 goto out_close_from;
1643
1644         err = kcore_copy__compare_fds(from, to);
1645
1646         close(to);
1647 out_close_from:
1648         close(from);
1649         return err;
1650 }
1651
1652 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
1653                                     const char *name)
1654 {
1655         char from_filename[PATH_MAX];
1656         char to_filename[PATH_MAX];
1657
1658         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1659         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1660
1661         return kcore_copy__compare_files(from_filename, to_filename);
1662 }
1663
1664 /**
1665  * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1666  * @from_dir: from directory
1667  * @to_dir: to directory
1668  *
1669  * This function copies kallsyms, modules and kcore files from one directory to
1670  * another.  kallsyms and modules are copied entirely.  Only code segments are
1671  * copied from kcore.  It is assumed that two segments suffice: one for the
1672  * kernel proper and one for all the modules.  The code segments are determined
1673  * from kallsyms and modules files.  The kernel map starts at _stext or the
1674  * lowest function symbol, and ends at _etext or the highest function symbol.
1675  * The module map starts at the lowest module address and ends at the highest
1676  * module symbol.  Start addresses are rounded down to the nearest page.  End
1677  * addresses are rounded up to the nearest page.  An extra page is added to the
1678  * highest kernel symbol and highest module symbol to, hopefully, encompass that
1679  * symbol too.  Because it contains only code sections, the resulting kcore is
1680  * unusual.  One significant peculiarity is that the mapping (start -> pgoff)
1681  * is not the same for the kernel map and the modules map.  That happens because
1682  * the data is copied adjacently whereas the original kcore has gaps.  Finally,
1683  * kallsyms and modules files are compared with their copies to check that
1684  * modules have not been loaded or unloaded while the copies were taking place.
1685  *
1686  * Return: %0 on success, %-1 on failure.
1687  */
1688 int kcore_copy(const char *from_dir, const char *to_dir)
1689 {
1690         struct kcore kcore;
1691         struct kcore extract;
1692         size_t count = 2;
1693         int idx = 0, err = -1;
1694         off_t offset = page_size, sz, modules_offset = 0;
1695         struct kcore_copy_info kci = { .stext = 0, };
1696         char kcore_filename[PATH_MAX];
1697         char extract_filename[PATH_MAX];
1698
1699         if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
1700                 return -1;
1701
1702         if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
1703                 goto out_unlink_kallsyms;
1704
1705         scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
1706         scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
1707
1708         if (kcore__open(&kcore, kcore_filename))
1709                 goto out_unlink_modules;
1710
1711         if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
1712                 goto out_kcore_close;
1713
1714         if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
1715                 goto out_kcore_close;
1716
1717         if (!kci.modules_map.addr)
1718                 count -= 1;
1719
1720         if (kcore__copy_hdr(&kcore, &extract, count))
1721                 goto out_extract_close;
1722
1723         if (kcore__add_phdr(&extract, idx++, offset, kci.kernel_map.addr,
1724                             kci.kernel_map.len))
1725                 goto out_extract_close;
1726
1727         if (kci.modules_map.addr) {
1728                 modules_offset = offset + kci.kernel_map.len;
1729                 if (kcore__add_phdr(&extract, idx, modules_offset,
1730                                     kci.modules_map.addr, kci.modules_map.len))
1731                         goto out_extract_close;
1732         }
1733
1734         sz = kcore__write(&extract);
1735         if (sz < 0 || sz > offset)
1736                 goto out_extract_close;
1737
1738         if (copy_bytes(kcore.fd, kci.kernel_map.offset, extract.fd, offset,
1739                        kci.kernel_map.len))
1740                 goto out_extract_close;
1741
1742         if (modules_offset && copy_bytes(kcore.fd, kci.modules_map.offset,
1743                                          extract.fd, modules_offset,
1744                                          kci.modules_map.len))
1745                 goto out_extract_close;
1746
1747         if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
1748                 goto out_extract_close;
1749
1750         if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
1751                 goto out_extract_close;
1752
1753         err = 0;
1754
1755 out_extract_close:
1756         kcore__close(&extract);
1757         if (err)
1758                 unlink(extract_filename);
1759 out_kcore_close:
1760         kcore__close(&kcore);
1761 out_unlink_modules:
1762         if (err)
1763                 kcore_copy__unlink(to_dir, "modules");
1764 out_unlink_kallsyms:
1765         if (err)
1766                 kcore_copy__unlink(to_dir, "kallsyms");
1767
1768         return err;
1769 }
1770
1771 int kcore_extract__create(struct kcore_extract *kce)
1772 {
1773         struct kcore kcore;
1774         struct kcore extract;
1775         size_t count = 1;
1776         int idx = 0, err = -1;
1777         off_t offset = page_size, sz;
1778
1779         if (kcore__open(&kcore, kce->kcore_filename))
1780                 return -1;
1781
1782         strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
1783         if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
1784                 goto out_kcore_close;
1785
1786         if (kcore__copy_hdr(&kcore, &extract, count))
1787                 goto out_extract_close;
1788
1789         if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
1790                 goto out_extract_close;
1791
1792         sz = kcore__write(&extract);
1793         if (sz < 0 || sz > offset)
1794                 goto out_extract_close;
1795
1796         if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
1797                 goto out_extract_close;
1798
1799         err = 0;
1800
1801 out_extract_close:
1802         kcore__close(&extract);
1803         if (err)
1804                 unlink(kce->extract_filename);
1805 out_kcore_close:
1806         kcore__close(&kcore);
1807
1808         return err;
1809 }
1810
1811 void kcore_extract__delete(struct kcore_extract *kce)
1812 {
1813         unlink(kce->extract_filename);
1814 }
1815
1816 #ifdef HAVE_GELF_GETNOTE_SUPPORT
1817 /**
1818  * populate_sdt_note : Parse raw data and identify SDT note
1819  * @elf: elf of the opened file
1820  * @data: raw data of a section with description offset applied
1821  * @len: note description size
1822  * @type: type of the note
1823  * @sdt_notes: List to add the SDT note
1824  *
1825  * Responsible for parsing the @data in section .note.stapsdt in @elf and
1826  * if its an SDT note, it appends to @sdt_notes list.
1827  */
1828 static int populate_sdt_note(Elf **elf, const char *data, size_t len,
1829                              struct list_head *sdt_notes)
1830 {
1831         const char *provider, *name;
1832         struct sdt_note *tmp = NULL;
1833         GElf_Ehdr ehdr;
1834         GElf_Addr base_off = 0;
1835         GElf_Shdr shdr;
1836         int ret = -EINVAL;
1837
1838         union {
1839                 Elf64_Addr a64[NR_ADDR];
1840                 Elf32_Addr a32[NR_ADDR];
1841         } buf;
1842
1843         Elf_Data dst = {
1844                 .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
1845                 .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),
1846                 .d_off = 0, .d_align = 0
1847         };
1848         Elf_Data src = {
1849                 .d_buf = (void *) data, .d_type = ELF_T_ADDR,
1850                 .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
1851                 .d_align = 0
1852         };
1853
1854         tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
1855         if (!tmp) {
1856                 ret = -ENOMEM;
1857                 goto out_err;
1858         }
1859
1860         INIT_LIST_HEAD(&tmp->note_list);
1861
1862         if (len < dst.d_size + 3)
1863                 goto out_free_note;
1864
1865         /* Translation from file representation to memory representation */
1866         if (gelf_xlatetom(*elf, &dst, &src,
1867                           elf_getident(*elf, NULL)[EI_DATA]) == NULL) {
1868                 pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
1869                 goto out_free_note;
1870         }
1871
1872         /* Populate the fields of sdt_note */
1873         provider = data + dst.d_size;
1874
1875         name = (const char *)memchr(provider, '\0', data + len - provider);
1876         if (name++ == NULL)
1877                 goto out_free_note;
1878
1879         tmp->provider = strdup(provider);
1880         if (!tmp->provider) {
1881                 ret = -ENOMEM;
1882                 goto out_free_note;
1883         }
1884         tmp->name = strdup(name);
1885         if (!tmp->name) {
1886                 ret = -ENOMEM;
1887                 goto out_free_prov;
1888         }
1889
1890         if (gelf_getclass(*elf) == ELFCLASS32) {
1891                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
1892                 tmp->bit32 = true;
1893         } else {
1894                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
1895                 tmp->bit32 = false;
1896         }
1897
1898         if (!gelf_getehdr(*elf, &ehdr)) {
1899                 pr_debug("%s : cannot get elf header.\n", __func__);
1900                 ret = -EBADF;
1901                 goto out_free_name;
1902         }
1903
1904         /* Adjust the prelink effect :
1905          * Find out the .stapsdt.base section.
1906          * This scn will help us to handle prelinking (if present).
1907          * Compare the retrieved file offset of the base section with the
1908          * base address in the description of the SDT note. If its different,
1909          * then accordingly, adjust the note location.
1910          */
1911         if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL)) {
1912                 base_off = shdr.sh_offset;
1913                 if (base_off) {
1914                         if (tmp->bit32)
1915                                 tmp->addr.a32[0] = tmp->addr.a32[0] + base_off -
1916                                         tmp->addr.a32[1];
1917                         else
1918                                 tmp->addr.a64[0] = tmp->addr.a64[0] + base_off -
1919                                         tmp->addr.a64[1];
1920                 }
1921         }
1922
1923         list_add_tail(&tmp->note_list, sdt_notes);
1924         return 0;
1925
1926 out_free_name:
1927         free(tmp->name);
1928 out_free_prov:
1929         free(tmp->provider);
1930 out_free_note:
1931         free(tmp);
1932 out_err:
1933         return ret;
1934 }
1935
1936 /**
1937  * construct_sdt_notes_list : constructs a list of SDT notes
1938  * @elf : elf to look into
1939  * @sdt_notes : empty list_head
1940  *
1941  * Scans the sections in 'elf' for the section
1942  * .note.stapsdt. It, then calls populate_sdt_note to find
1943  * out the SDT events and populates the 'sdt_notes'.
1944  */
1945 static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
1946 {
1947         GElf_Ehdr ehdr;
1948         Elf_Scn *scn = NULL;
1949         Elf_Data *data;
1950         GElf_Shdr shdr;
1951         size_t shstrndx, next;
1952         GElf_Nhdr nhdr;
1953         size_t name_off, desc_off, offset;
1954         int ret = 0;
1955
1956         if (gelf_getehdr(elf, &ehdr) == NULL) {
1957                 ret = -EBADF;
1958                 goto out_ret;
1959         }
1960         if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
1961                 ret = -EBADF;
1962                 goto out_ret;
1963         }
1964
1965         /* Look for the required section */
1966         scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
1967         if (!scn) {
1968                 ret = -ENOENT;
1969                 goto out_ret;
1970         }
1971
1972         if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
1973                 ret = -ENOENT;
1974                 goto out_ret;
1975         }
1976
1977         data = elf_getdata(scn, NULL);
1978
1979         /* Get the SDT notes */
1980         for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
1981                                               &desc_off)) > 0; offset = next) {
1982                 if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
1983                     !memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
1984                             sizeof(SDT_NOTE_NAME))) {
1985                         /* Check the type of the note */
1986                         if (nhdr.n_type != SDT_NOTE_TYPE)
1987                                 goto out_ret;
1988
1989                         ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
1990                                                 nhdr.n_descsz, sdt_notes);
1991                         if (ret < 0)
1992                                 goto out_ret;
1993                 }
1994         }
1995         if (list_empty(sdt_notes))
1996                 ret = -ENOENT;
1997
1998 out_ret:
1999         return ret;
2000 }
2001
2002 /**
2003  * get_sdt_note_list : Wrapper to construct a list of sdt notes
2004  * @head : empty list_head
2005  * @target : file to find SDT notes from
2006  *
2007  * This opens the file, initializes
2008  * the ELF and then calls construct_sdt_notes_list.
2009  */
2010 int get_sdt_note_list(struct list_head *head, const char *target)
2011 {
2012         Elf *elf;
2013         int fd, ret;
2014
2015         fd = open(target, O_RDONLY);
2016         if (fd < 0)
2017                 return -EBADF;
2018
2019         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
2020         if (!elf) {
2021                 ret = -EBADF;
2022                 goto out_close;
2023         }
2024         ret = construct_sdt_notes_list(elf, head);
2025         elf_end(elf);
2026 out_close:
2027         close(fd);
2028         return ret;
2029 }
2030
2031 /**
2032  * cleanup_sdt_note_list : free the sdt notes' list
2033  * @sdt_notes: sdt notes' list
2034  *
2035  * Free up the SDT notes in @sdt_notes.
2036  * Returns the number of SDT notes free'd.
2037  */
2038 int cleanup_sdt_note_list(struct list_head *sdt_notes)
2039 {
2040         struct sdt_note *tmp, *pos;
2041         int nr_free = 0;
2042
2043         list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
2044                 list_del(&pos->note_list);
2045                 free(pos->name);
2046                 free(pos->provider);
2047                 free(pos);
2048                 nr_free++;
2049         }
2050         return nr_free;
2051 }
2052
2053 /**
2054  * sdt_notes__get_count: Counts the number of sdt events
2055  * @start: list_head to sdt_notes list
2056  *
2057  * Returns the number of SDT notes in a list
2058  */
2059 int sdt_notes__get_count(struct list_head *start)
2060 {
2061         struct sdt_note *sdt_ptr;
2062         int count = 0;
2063
2064         list_for_each_entry(sdt_ptr, start, note_list)
2065                 count++;
2066         return count;
2067 }
2068 #endif
2069
2070 void symbol__elf_init(void)
2071 {
2072         elf_version(EV_CURRENT);
2073 }