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 "debug.h"
  14 #include "sane_ctype.h"
  15 #include <symbol/kallsyms.h>
  16
  17 #ifndef EM_AARCH64
  18 #define EM_AARCH64      183  /* ARM 64 bit */
  19 #endif
  20
  21 typedef Elf64_Nhdr GElf_Nhdr;
  22
  23 #ifdef HAVE_CPLUS_DEMANGLE_SUPPORT
  24 extern char *cplus_demangle(const char *, int);
  25
  26 static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i)
  27 {
  28         return cplus_demangle(c, i);
  29 }
  30 #else
  31 #ifdef NO_DEMANGLE
  32 static inline char *bfd_demangle(void __maybe_unused *v,
  33                                  const char __maybe_unused *c,
  34                                  int __maybe_unused i)
  35 {
  36         return NULL;
  37 }
  38 #else
  39 #define PACKAGE 'perf'
  40 #include <bfd.h>
  41 #endif
  42 #endif
  43
  44 #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
  45 static int elf_getphdrnum(Elf *elf, size_t *dst)
  46 {
  47         GElf_Ehdr gehdr;
  48         GElf_Ehdr *ehdr;
  49
  50         ehdr = gelf_getehdr(elf, &gehdr);
  51         if (!ehdr)
  52                 return -1;
  53
  54         *dst = ehdr->e_phnum;
  55
  56         return 0;
  57 }
  58 #endif
  59
  60 #ifndef HAVE_ELF_GETSHDRSTRNDX_SUPPORT
  61 static int elf_getshdrstrndx(Elf *elf __maybe_unused, size_t *dst __maybe_unused)
  62 {
  63         pr_err("%s: update your libelf to > 0.140, this one lacks elf_getshdrstrndx().\n", __func__);
  64         return -1;
  65 }
  66 #endif
  67
  68 #ifndef NT_GNU_BUILD_ID
  69 #define NT_GNU_BUILD_ID 3
  70 #endif
  71
  72 /**
  73  * elf_symtab__for_each_symbol - iterate thru all the symbols
  74  *
  75  * @syms: struct elf_symtab instance to iterate
  76  * @idx: uint32_t idx
  77  * @sym: GElf_Sym iterator
  78  */
  79 #define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
  80         for (idx = 0, gelf_getsym(syms, idx, &sym);\
  81              idx < nr_syms; \
  82              idx++, gelf_getsym(syms, idx, &sym))
  83
  84 static inline uint8_t elf_sym__type(const GElf_Sym *sym)
  85 {
  86         return GELF_ST_TYPE(sym->st_info);
  87 }
  88
  89 #ifndef STT_GNU_IFUNC
  90 #define STT_GNU_IFUNC 10
  91 #endif
  92
  93 static inline int elf_sym__is_function(const GElf_Sym *sym)
  94 {
  95         return (elf_sym__type(sym) == STT_FUNC ||
  96                 elf_sym__type(sym) == STT_GNU_IFUNC) &&
  97                sym->st_name != 0 &&
  98                sym->st_shndx != SHN_UNDEF;
  99 }
 100
 101 static inline bool elf_sym__is_object(const GElf_Sym *sym)
 102 {
 103         return elf_sym__type(sym) == STT_OBJECT &&
 104                 sym->st_name != 0 &&
 105                 sym->st_shndx != SHN_UNDEF;
 106 }
 107
 108 static inline int elf_sym__is_label(const GElf_Sym *sym)
 109 {
 110         return elf_sym__type(sym) == STT_NOTYPE &&
 111                 sym->st_name != 0 &&
 112                 sym->st_shndx != SHN_UNDEF &&
 113                 sym->st_shndx != SHN_ABS;
 114 }
 115
 116 static bool elf_sym__is_a(GElf_Sym *sym, enum map_type type)
 117 {
 118         switch (type) {
 119         case MAP__FUNCTION:
 120                 return elf_sym__is_function(sym);
 121         case MAP__VARIABLE:
 122                 return elf_sym__is_object(sym);
 123         default:
 124                 return false;
 125         }
 126 }
 127
 128 static inline const char *elf_sym__name(const GElf_Sym *sym,
 129                                         const Elf_Data *symstrs)
 130 {
 131         return symstrs->d_buf + sym->st_name;
 132 }
 133
 134 static inline const char *elf_sec__name(const GElf_Shdr *shdr,
 135                                         const Elf_Data *secstrs)
 136 {
 137         return secstrs->d_buf + shdr->sh_name;
 138 }
 139
 140 static inline int elf_sec__is_text(const GElf_Shdr *shdr,
 141                                         const Elf_Data *secstrs)
 142 {
 143         return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
 144 }
 145
 146 static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
 147                                     const Elf_Data *secstrs)
 148 {
 149         return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
 150 }
 151
 152 static bool elf_sec__is_a(GElf_Shdr *shdr, Elf_Data *secstrs,
 153                           enum map_type type)
 154 {
 155         switch (type) {
 156         case MAP__FUNCTION:
 157                 return elf_sec__is_text(shdr, secstrs);
 158         case MAP__VARIABLE:
 159                 return elf_sec__is_data(shdr, secstrs);
 160         default:
 161                 return false;
 162         }
 163 }
 164
 165 static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
 166 {
 167         Elf_Scn *sec = NULL;
 168         GElf_Shdr shdr;
 169         size_t cnt = 1;
 170
 171         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 172                 gelf_getshdr(sec, &shdr);
 173
 174                 if ((addr >= shdr.sh_addr) &&
 175                     (addr < (shdr.sh_addr + shdr.sh_size)))
 176                         return cnt;
 177
 178                 ++cnt;
 179         }
 180
 181         return -1;
 182 }
 183
 184 Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
 185                              GElf_Shdr *shp, const char *name, size_t *idx)
 186 {
 187         Elf_Scn *sec = NULL;
 188         size_t cnt = 1;
 189
 190         /* Elf is corrupted/truncated, avoid calling elf_strptr. */
 191         if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
 192                 return NULL;
 193
 194         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 195                 char *str;
 196
 197                 gelf_getshdr(sec, shp);
 198                 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
 199                 if (str && !strcmp(name, str)) {
 200                         if (idx)
 201                                 *idx = cnt;
 202                         return sec;
 203                 }
 204                 ++cnt;
 205         }
 206
 207         return NULL;
 208 }
 209
 210 static bool want_demangle(bool is_kernel_sym)
 211 {
 212         return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
 213 }
 214
 215 static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
 216 {
 217         int demangle_flags = verbose > 0 ? (DMGL_PARAMS | DMGL_ANSI) : DMGL_NO_OPTS;
 218         char *demangled = NULL;
 219
 220         /*
 221          * We need to figure out if the object was created from C++ sources
 222          * DWARF DW_compile_unit has this, but we don't always have access
 223          * to it...
 224          */
 225         if (!want_demangle(dso->kernel || kmodule))
 226             return demangled;
 227
 228         demangled = bfd_demangle(NULL, elf_name, demangle_flags);
 229         if (demangled == NULL)
 230                 demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
 231         else if (rust_is_mangled(demangled))
 232                 /*
 233                     * Input to Rust demangling is the BFD-demangled
 234                     * name which it Rust-demangles in place.
 235                     */
 236                 rust_demangle_sym(demangled);
 237
 238         return demangled;
 239 }
 240
 241 #define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
 242         for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
 243              idx < nr_entries; \
 244              ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
 245
 246 #define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
 247         for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
 248              idx < nr_entries; \
 249              ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
 250
 251 /*
 252  * We need to check if we have a .dynsym, so that we can handle the
 253  * .plt, synthesizing its symbols, that aren't on the symtabs (be it
 254  * .dynsym or .symtab).
 255  * And always look at the original dso, not at debuginfo packages, that
 256  * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
 257  */
 258 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss, struct map *map)
 259 {
 260         uint32_t nr_rel_entries, idx;
 261         GElf_Sym sym;
 262         u64 plt_offset;
 263         GElf_Shdr shdr_plt;
 264         struct symbol *f;
 265         GElf_Shdr shdr_rel_plt, shdr_dynsym;
 266         Elf_Data *reldata, *syms, *symstrs;
 267         Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
 268         size_t dynsym_idx;
 269         GElf_Ehdr ehdr;
 270         char sympltname[1024];
 271         Elf *elf;
 272         int nr = 0, symidx, err = 0;
 273
 274         if (!ss->dynsym)
 275                 return 0;
 276
 277         elf = ss->elf;
 278         ehdr = ss->ehdr;
 279
 280         scn_dynsym = ss->dynsym;
 281         shdr_dynsym = ss->dynshdr;
 282         dynsym_idx = ss->dynsym_idx;
 283
 284         if (scn_dynsym == NULL)
 285                 goto out_elf_end;
 286
 287         scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 288                                           ".rela.plt", NULL);
 289         if (scn_plt_rel == NULL) {
 290                 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 291                                                   ".rel.plt", NULL);
 292                 if (scn_plt_rel == NULL)
 293                         goto out_elf_end;
 294         }
 295
 296         err = -1;
 297
 298         if (shdr_rel_plt.sh_link != dynsym_idx)
 299                 goto out_elf_end;
 300
 301         if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
 302                 goto out_elf_end;
 303
 304         /*
 305          * Fetch the relocation section to find the idxes to the GOT
 306          * and the symbols in the .dynsym they refer to.
 307          */
 308         reldata = elf_getdata(scn_plt_rel, NULL);
 309         if (reldata == NULL)
 310                 goto out_elf_end;
 311
 312         syms = elf_getdata(scn_dynsym, NULL);
 313         if (syms == NULL)
 314                 goto out_elf_end;
 315
 316         scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
 317         if (scn_symstrs == NULL)
 318                 goto out_elf_end;
 319
 320         symstrs = elf_getdata(scn_symstrs, NULL);
 321         if (symstrs == NULL)
 322                 goto out_elf_end;
 323
 324         if (symstrs->d_size == 0)
 325                 goto out_elf_end;
 326
 327         nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
 328         plt_offset = shdr_plt.sh_offset;
 329
 330         if (shdr_rel_plt.sh_type == SHT_RELA) {
 331                 GElf_Rela pos_mem, *pos;
 332
 333                 elf_section__for_each_rela(reldata, pos, pos_mem, idx,
 334                                            nr_rel_entries) {
 335                         const char *elf_name = NULL;
 336                         char *demangled = NULL;
 337                         symidx = GELF_R_SYM(pos->r_info);
 338                         plt_offset += shdr_plt.sh_entsize;
 339                         gelf_getsym(syms, symidx, &sym);
 340
 341                         elf_name = elf_sym__name(&sym, symstrs);
 342                         demangled = demangle_sym(dso, 0, elf_name);
 343                         if (demangled != NULL)
 344                                 elf_name = demangled;
 345                         snprintf(sympltname, sizeof(sympltname),
 346                                  "%s@plt", elf_name);
 347                         free(demangled);
 348
 349                         f = symbol__new(plt_offset, shdr_plt.sh_entsize,
 350                                         STB_GLOBAL, sympltname);
 351                         if (!f)
 352                                 goto out_elf_end;
 353
 354                         symbols__insert(&dso->symbols[map->type], f);
 355                         ++nr;
 356                 }
 357         } else if (shdr_rel_plt.sh_type == SHT_REL) {
 358                 GElf_Rel pos_mem, *pos;
 359                 elf_section__for_each_rel(reldata, pos, pos_mem, idx,
 360                                           nr_rel_entries) {
 361                         const char *elf_name = NULL;
 362                         char *demangled = NULL;
 363                         symidx = GELF_R_SYM(pos->r_info);
 364                         plt_offset += shdr_plt.sh_entsize;
 365                         gelf_getsym(syms, symidx, &sym);
 366
 367                         elf_name = elf_sym__name(&sym, symstrs);
 368                         demangled = demangle_sym(dso, 0, elf_name);
 369                         if (demangled != NULL)
 370                                 elf_name = demangled;
 371                         snprintf(sympltname, sizeof(sympltname),
 372                                  "%s@plt", elf_name);
 373                         free(demangled);
 374
 375                         f = symbol__new(plt_offset, shdr_plt.sh_entsize,
 376                                         STB_GLOBAL, sympltname);
 377                         if (!f)
 378                                 goto out_elf_end;
 379
 380                         symbols__insert(&dso->symbols[map->type], f);
 381                         ++nr;
 382                 }
 383         }
 384
 385         err = 0;
 386 out_elf_end:
 387         if (err == 0)
 388                 return nr;
 389         pr_debug("%s: problems reading %s PLT info.\n",
 390                  __func__, dso->long_name);
 391         return 0;
 392 }
 393
 394 char *dso__demangle_sym(struct dso *dso, int kmodule, char *elf_name)
 395 {
 396         return demangle_sym(dso, kmodule, elf_name);
 397 }
 398
 399 /*
 400  * Align offset to 4 bytes as needed for note name and descriptor data.
 401  */
 402 #define NOTE_ALIGN(n) (((n) + 3) & -4U)
 403
 404 static int elf_read_build_id(Elf *elf, void *bf, size_t size)
 405 {
 406         int err = -1;
 407         GElf_Ehdr ehdr;
 408         GElf_Shdr shdr;
 409         Elf_Data *data;
 410         Elf_Scn *sec;
 411         Elf_Kind ek;
 412         void *ptr;
 413
 414         if (size < BUILD_ID_SIZE)
 415                 goto out;
 416
 417         ek = elf_kind(elf);
 418         if (ek != ELF_K_ELF)
 419                 goto out;
 420
 421         if (gelf_getehdr(elf, &ehdr) == NULL) {
 422                 pr_err("%s: cannot get elf header.\n", __func__);
 423                 goto out;
 424         }
 425
 426         /*
 427          * Check following sections for notes:
 428          *   '.note.gnu.build-id'
 429          *   '.notes'
 430          *   '.note' (VDSO specific)
 431          */
 432         do {
 433                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 434                                           ".note.gnu.build-id", NULL);
 435                 if (sec)
 436                         break;
 437
 438                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 439                                           ".notes", NULL);
 440                 if (sec)
 441                         break;
 442
 443                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 444                                           ".note", NULL);
 445                 if (sec)
 446                         break;
 447
 448                 return err;
 449
 450         } while (0);
 451
 452         data = elf_getdata(sec, NULL);
 453         if (data == NULL)
 454                 goto out;
 455
 456         ptr = data->d_buf;
 457         while (ptr < (data->d_buf + data->d_size)) {
 458                 GElf_Nhdr *nhdr = ptr;
 459                 size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
 460                        descsz = NOTE_ALIGN(nhdr->n_descsz);
 461                 const char *name;
 462
 463                 ptr += sizeof(*nhdr);
 464                 name = ptr;
 465                 ptr += namesz;
 466                 if (nhdr->n_type == NT_GNU_BUILD_ID &&
 467                     nhdr->n_namesz == sizeof("GNU")) {
 468                         if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
 469                                 size_t sz = min(size, descsz);
 470                                 memcpy(bf, ptr, sz);
 471                                 memset(bf + sz, 0, size - sz);
 472                                 err = descsz;
 473                                 break;
 474                         }
 475                 }
 476                 ptr += descsz;
 477         }
 478
 479 out:
 480         return err;
 481 }
 482
 483 int filename__read_build_id(const char *filename, void *bf, size_t size)
 484 {
 485         int fd, err = -1;
 486         Elf *elf;
 487
 488         if (size < BUILD_ID_SIZE)
 489                 goto out;
 490
 491         fd = open(filename, O_RDONLY);
 492         if (fd < 0)
 493                 goto out;
 494
 495         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 496         if (elf == NULL) {
 497                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 498                 goto out_close;
 499         }
 500
 501         err = elf_read_build_id(elf, bf, size);
 502
 503         elf_end(elf);
 504 out_close:
 505         close(fd);
 506 out:
 507         return err;
 508 }
 509
 510 int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
 511 {
 512         int fd, err = -1;
 513
 514         if (size < BUILD_ID_SIZE)
 515                 goto out;
 516
 517         fd = open(filename, O_RDONLY);
 518         if (fd < 0)
 519                 goto out;
 520
 521         while (1) {
 522                 char bf[BUFSIZ];
 523                 GElf_Nhdr nhdr;
 524                 size_t namesz, descsz;
 525
 526                 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
 527                         break;
 528
 529                 namesz = NOTE_ALIGN(nhdr.n_namesz);
 530                 descsz = NOTE_ALIGN(nhdr.n_descsz);
 531                 if (nhdr.n_type == NT_GNU_BUILD_ID &&
 532                     nhdr.n_namesz == sizeof("GNU")) {
 533                         if (read(fd, bf, namesz) != (ssize_t)namesz)
 534                                 break;
 535                         if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
 536                                 size_t sz = min(descsz, size);
 537                                 if (read(fd, build_id, sz) == (ssize_t)sz) {
 538                                         memset(build_id + sz, 0, size - sz);
 539                                         err = 0;
 540                                         break;
 541                                 }
 542                         } else if (read(fd, bf, descsz) != (ssize_t)descsz)
 543                                 break;
 544                 } else {
 545                         int n = namesz + descsz;
 546
 547                         if (n > (int)sizeof(bf)) {
 548                                 n = sizeof(bf);
 549                                 pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n",
 550                                          __func__, filename, nhdr.n_namesz, nhdr.n_descsz);
 551                         }
 552                         if (read(fd, bf, n) != n)
 553                                 break;
 554                 }
 555         }
 556         close(fd);
 557 out:
 558         return err;
 559 }
 560
 561 int filename__read_debuglink(const char *filename, char *debuglink,
 562                              size_t size)
 563 {
 564         int fd, err = -1;
 565         Elf *elf;
 566         GElf_Ehdr ehdr;
 567         GElf_Shdr shdr;
 568         Elf_Data *data;
 569         Elf_Scn *sec;
 570         Elf_Kind ek;
 571
 572         fd = open(filename, O_RDONLY);
 573         if (fd < 0)
 574                 goto out;
 575
 576         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 577         if (elf == NULL) {
 578                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 579                 goto out_close;
 580         }
 581
 582         ek = elf_kind(elf);
 583         if (ek != ELF_K_ELF)
 584                 goto out_elf_end;
 585
 586         if (gelf_getehdr(elf, &ehdr) == NULL) {
 587                 pr_err("%s: cannot get elf header.\n", __func__);
 588                 goto out_elf_end;
 589         }
 590
 591         sec = elf_section_by_name(elf, &ehdr, &shdr,
 592                                   ".gnu_debuglink", NULL);
 593         if (sec == NULL)
 594                 goto out_elf_end;
 595
 596         data = elf_getdata(sec, NULL);
 597         if (data == NULL)
 598                 goto out_elf_end;
 599
 600         /* the start of this section is a zero-terminated string */
 601         strncpy(debuglink, data->d_buf, size);
 602
 603         err = 0;
 604
 605 out_elf_end:
 606         elf_end(elf);
 607 out_close:
 608         close(fd);
 609 out:
 610         return err;
 611 }
 612
 613 static int dso__swap_init(struct dso *dso, unsigned char eidata)
 614 {
 615         static unsigned int const endian = 1;
 616
 617         dso->needs_swap = DSO_SWAP__NO;
 618
 619         switch (eidata) {
 620         case ELFDATA2LSB:
 621                 /* We are big endian, DSO is little endian. */
 622                 if (*(unsigned char const *)&endian != 1)
 623                         dso->needs_swap = DSO_SWAP__YES;
 624                 break;
 625
 626         case ELFDATA2MSB:
 627                 /* We are little endian, DSO is big endian. */
 628                 if (*(unsigned char const *)&endian != 0)
 629                         dso->needs_swap = DSO_SWAP__YES;
 630                 break;
 631
 632         default:
 633                 pr_err("unrecognized DSO data encoding %d\n", eidata);
 634                 return -EINVAL;
 635         }
 636
 637         return 0;
 638 }
 639
 640 bool symsrc__possibly_runtime(struct symsrc *ss)
 641 {
 642         return ss->dynsym || ss->opdsec;
 643 }
 644
 645 bool symsrc__has_symtab(struct symsrc *ss)
 646 {
 647         return ss->symtab != NULL;
 648 }
 649
 650 void symsrc__destroy(struct symsrc *ss)
 651 {
 652         zfree(&ss->name);
 653         elf_end(ss->elf);
 654         close(ss->fd);
 655 }
 656
 657 bool __weak elf__needs_adjust_symbols(GElf_Ehdr ehdr)
 658 {
 659         return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL;
 660 }
 661
 662 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
 663                  enum dso_binary_type type)
 664 {
 665         int err = -1;
 666         GElf_Ehdr ehdr;
 667         Elf *elf;
 668         int fd;
 669
 670         if (dso__needs_decompress(dso)) {
 671                 fd = dso__decompress_kmodule_fd(dso, name);
 672                 if (fd < 0)
 673                         return -1;
 674
 675                 type = dso->symtab_type;
 676         } else {
 677                 fd = open(name, O_RDONLY);
 678                 if (fd < 0) {
 679                         dso->load_errno = errno;
 680                         return -1;
 681                 }
 682         }
 683
 684         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 685         if (elf == NULL) {
 686                 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
 687                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 688                 goto out_close;
 689         }
 690
 691         if (gelf_getehdr(elf, &ehdr) == NULL) {
 692                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 693                 pr_debug("%s: cannot get elf header.\n", __func__);
 694                 goto out_elf_end;
 695         }
 696
 697         if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
 698                 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
 699                 goto out_elf_end;
 700         }
 701
 702         /* Always reject images with a mismatched build-id: */
 703         if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) {
 704                 u8 build_id[BUILD_ID_SIZE];
 705
 706                 if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) {
 707                         dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
 708                         goto out_elf_end;
 709                 }
 710
 711                 if (!dso__build_id_equal(dso, build_id)) {
 712                         pr_debug("%s: build id mismatch for %s.\n", __func__, name);
 713                         dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
 714                         goto out_elf_end;
 715                 }
 716         }
 717
 718         ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
 719
 720         ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
 721                         NULL);
 722         if (ss->symshdr.sh_type != SHT_SYMTAB)
 723                 ss->symtab = NULL;
 724
 725         ss->dynsym_idx = 0;
 726         ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
 727                         &ss->dynsym_idx);
 728         if (ss->dynshdr.sh_type != SHT_DYNSYM)
 729                 ss->dynsym = NULL;
 730
 731         ss->opdidx = 0;
 732         ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
 733                         &ss->opdidx);
 734         if (ss->opdshdr.sh_type != SHT_PROGBITS)
 735                 ss->opdsec = NULL;
 736
 737         if (dso->kernel == DSO_TYPE_USER)
 738                 ss->adjust_symbols = true;
 739         else
 740                 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
 741
 742         ss->name   = strdup(name);
 743         if (!ss->name) {
 744                 dso->load_errno = errno;
 745                 goto out_elf_end;
 746         }
 747
 748         ss->elf    = elf;
 749         ss->fd     = fd;
 750         ss->ehdr   = ehdr;
 751         ss->type   = type;
 752
 753         return 0;
 754
 755 out_elf_end:
 756         elf_end(elf);
 757 out_close:
 758         close(fd);
 759         return err;
 760 }
 761
 762 /**
 763  * ref_reloc_sym_not_found - has kernel relocation symbol been found.
 764  * @kmap: kernel maps and relocation reference symbol
 765  *
 766  * This function returns %true if we are dealing with the kernel maps and the
 767  * relocation reference symbol has not yet been found.  Otherwise %false is
 768  * returned.
 769  */
 770 static bool ref_reloc_sym_not_found(struct kmap *kmap)
 771 {
 772         return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
 773                !kmap->ref_reloc_sym->unrelocated_addr;
 774 }
 775
 776 /**
 777  * ref_reloc - kernel relocation offset.
 778  * @kmap: kernel maps and relocation reference symbol
 779  *
 780  * This function returns the offset of kernel addresses as determined by using
 781  * the relocation reference symbol i.e. if the kernel has not been relocated
 782  * then the return value is zero.
 783  */
 784 static u64 ref_reloc(struct kmap *kmap)
 785 {
 786         if (kmap && kmap->ref_reloc_sym &&
 787             kmap->ref_reloc_sym->unrelocated_addr)
 788                 return kmap->ref_reloc_sym->addr -
 789                        kmap->ref_reloc_sym->unrelocated_addr;
 790         return 0;
 791 }
 792
 793 void __weak arch__sym_update(struct symbol *s __maybe_unused,
 794                 GElf_Sym *sym __maybe_unused) { }
 795
 796 int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
 797                   struct symsrc *runtime_ss, int kmodule)
 798 {
 799         struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
 800         struct map_groups *kmaps = kmap ? map__kmaps(map) : NULL;
 801         struct map *curr_map = map;
 802         struct dso *curr_dso = dso;
 803         Elf_Data *symstrs, *secstrs;
 804         uint32_t nr_syms;
 805         int err = -1;
 806         uint32_t idx;
 807         GElf_Ehdr ehdr;
 808         GElf_Shdr shdr;
 809         GElf_Shdr tshdr;
 810         Elf_Data *syms, *opddata = NULL;
 811         GElf_Sym sym;
 812         Elf_Scn *sec, *sec_strndx;
 813         Elf *elf;
 814         int nr = 0;
 815         bool remap_kernel = false, adjust_kernel_syms = false;
 816
 817         if (kmap && !kmaps)
 818                 return -1;
 819
 820         dso->symtab_type = syms_ss->type;
 821         dso->is_64_bit = syms_ss->is_64_bit;
 822         dso->rel = syms_ss->ehdr.e_type == ET_REL;
 823
 824         /*
 825          * Modules may already have symbols from kallsyms, but those symbols
 826          * have the wrong values for the dso maps, so remove them.
 827          */
 828         if (kmodule && syms_ss->symtab)
 829                 symbols__delete(&dso->symbols[map->type]);
 830
 831         if (!syms_ss->symtab) {
 832                 /*
 833                  * If the vmlinux is stripped, fail so we will fall back
 834                  * to using kallsyms. The vmlinux runtime symbols aren't
 835                  * of much use.
 836                  */
 837                 if (dso->kernel)
 838                         goto out_elf_end;
 839
 840                 syms_ss->symtab  = syms_ss->dynsym;
 841                 syms_ss->symshdr = syms_ss->dynshdr;
 842         }
 843
 844         elf = syms_ss->elf;
 845         ehdr = syms_ss->ehdr;
 846         sec = syms_ss->symtab;
 847         shdr = syms_ss->symshdr;
 848
 849         if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
 850                                 ".text", NULL))
 851                 dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
 852
 853         if (runtime_ss->opdsec)
 854                 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
 855
 856         syms = elf_getdata(sec, NULL);
 857         if (syms == NULL)
 858                 goto out_elf_end;
 859
 860         sec = elf_getscn(elf, shdr.sh_link);
 861         if (sec == NULL)
 862                 goto out_elf_end;
 863
 864         symstrs = elf_getdata(sec, NULL);
 865         if (symstrs == NULL)
 866                 goto out_elf_end;
 867
 868         sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
 869         if (sec_strndx == NULL)
 870                 goto out_elf_end;
 871
 872         secstrs = elf_getdata(sec_strndx, NULL);
 873         if (secstrs == NULL)
 874                 goto out_elf_end;
 875
 876         nr_syms = shdr.sh_size / shdr.sh_entsize;
 877
 878         memset(&sym, 0, sizeof(sym));
 879
 880         /*
 881          * The kernel relocation symbol is needed in advance in order to adjust
 882          * kernel maps correctly.
 883          */
 884         if (ref_reloc_sym_not_found(kmap)) {
 885                 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
 886                         const char *elf_name = elf_sym__name(&sym, symstrs);
 887
 888                         if (strcmp(elf_name, kmap->ref_reloc_sym->name))
 889                                 continue;
 890                         kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
 891                         map->reloc = kmap->ref_reloc_sym->addr -
 892                                      kmap->ref_reloc_sym->unrelocated_addr;
 893                         break;
 894                 }
 895         }
 896
 897         /*
 898          * Handle any relocation of vdso necessary because older kernels
 899          * attempted to prelink vdso to its virtual address.
 900          */
 901         if (dso__is_vdso(dso))
 902                 map->reloc = map->start - dso->text_offset;
 903
 904         dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
 905         /*
 906          * Initial kernel and module mappings do not map to the dso.  For
 907          * function mappings, flag the fixups.
 908          */
 909         if (map->type == MAP__FUNCTION && (dso->kernel || kmodule)) {
 910                 remap_kernel = true;
 911                 adjust_kernel_syms = dso->adjust_symbols;
 912         }
 913         elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
 914                 struct symbol *f;
 915                 const char *elf_name = elf_sym__name(&sym, symstrs);
 916                 char *demangled = NULL;
 917                 int is_label = elf_sym__is_label(&sym);
 918                 const char *section_name;
 919                 bool used_opd = false;
 920
 921                 if (!is_label && !elf_sym__is_a(&sym, map->type))
 922                         continue;
 923
 924                 /* Reject ARM ELF "mapping symbols": these aren't unique and
 925                  * don't identify functions, so will confuse the profile
 926                  * output: */
 927                 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
 928                         if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
 929                             && (elf_name[2] == '\0' || elf_name[2] == '.'))
 930                                 continue;
 931                 }
 932
 933                 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
 934                         u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
 935                         u64 *opd = opddata->d_buf + offset;
 936                         sym.st_value = DSO__SWAP(dso, u64, *opd);
 937                         sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
 938                                         sym.st_value);
 939                         used_opd = true;
 940                 }
 941                 /*
 942                  * When loading symbols in a data mapping, ABS symbols (which
 943                  * has a value of SHN_ABS in its st_shndx) failed at
 944                  * elf_getscn().  And it marks the loading as a failure so
 945                  * already loaded symbols cannot be fixed up.
 946                  *
 947                  * I'm not sure what should be done. Just ignore them for now.
 948                  * - Namhyung Kim
 949                  */
 950                 if (sym.st_shndx == SHN_ABS)
 951                         continue;
 952
 953                 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
 954                 if (!sec)
 955                         goto out_elf_end;
 956
 957                 gelf_getshdr(sec, &shdr);
 958
 959                 if (is_label && !elf_sec__is_a(&shdr, secstrs, map->type))
 960                         continue;
 961
 962                 section_name = elf_sec__name(&shdr, secstrs);
 963
 964                 /* On ARM, symbols for thumb functions have 1 added to
 965                  * the symbol address as a flag - remove it */
 966                 if ((ehdr.e_machine == EM_ARM) &&
 967                     (map->type == MAP__FUNCTION) &&
 968                     (sym.st_value & 1))
 969                         --sym.st_value;
 970
 971                 if (dso->kernel || kmodule) {
 972                         char dso_name[PATH_MAX];
 973
 974                         /* Adjust symbol to map to file offset */
 975                         if (adjust_kernel_syms)
 976                                 sym.st_value -= shdr.sh_addr - shdr.sh_offset;
 977
 978                         if (strcmp(section_name,
 979                                    (curr_dso->short_name +
 980                                     dso->short_name_len)) == 0)
 981                                 goto new_symbol;
 982
 983                         if (strcmp(section_name, ".text") == 0) {
 984                                 /*
 985                                  * The initial kernel mapping is based on
 986                                  * kallsyms and identity maps.  Overwrite it to
 987                                  * map to the kernel dso.
 988                                  */
 989                                 if (remap_kernel && dso->kernel) {
 990                                         remap_kernel = false;
 991                                         map->start = shdr.sh_addr +
 992                                                      ref_reloc(kmap);
 993                                         map->end = map->start + shdr.sh_size;
 994                                         map->pgoff = shdr.sh_offset;
 995                                         map->map_ip = map__map_ip;
 996                                         map->unmap_ip = map__unmap_ip;
 997                                         /* Ensure maps are correctly ordered */
 998                                         if (kmaps) {
 999                                                 map__get(map);
1000                                                 map_groups__remove(kmaps, map);
1001                                                 map_groups__insert(kmaps, map);
1002                                                 map__put(map);
1003                                         }
1004                                 }
1005
1006                                 /*
1007                                  * The initial module mapping is based on
1008                                  * /proc/modules mapped to offset zero.
1009                                  * Overwrite it to map to the module dso.
1010                                  */
1011                                 if (remap_kernel && kmodule) {
1012                                         remap_kernel = false;
1013                                         map->pgoff = shdr.sh_offset;
1014                                 }
1015
1016                                 curr_map = map;
1017                                 curr_dso = dso;
1018                                 goto new_symbol;
1019                         }
1020
1021                         if (!kmap)
1022                                 goto new_symbol;
1023
1024                         snprintf(dso_name, sizeof(dso_name),
1025                                  "%s%s", dso->short_name, section_name);
1026
1027                         curr_map = map_groups__find_by_name(kmaps, map->type, dso_name);
1028                         if (curr_map == NULL) {
1029                                 u64 start = sym.st_value;
1030
1031                                 if (kmodule)
1032                                         start += map->start + shdr.sh_offset;
1033
1034                                 curr_dso = dso__new(dso_name);
1035                                 if (curr_dso == NULL)
1036                                         goto out_elf_end;
1037                                 curr_dso->kernel = dso->kernel;
1038                                 curr_dso->long_name = dso->long_name;
1039                                 curr_dso->long_name_len = dso->long_name_len;
1040                                 curr_map = map__new2(start, curr_dso,
1041                                                      map->type);
1042                                 dso__put(curr_dso);
1043                                 if (curr_map == NULL) {
1044                                         goto out_elf_end;
1045                                 }
1046                                 if (adjust_kernel_syms) {
1047                                         curr_map->start = shdr.sh_addr +
1048                                                           ref_reloc(kmap);
1049                                         curr_map->end = curr_map->start +
1050                                                         shdr.sh_size;
1051                                         curr_map->pgoff = shdr.sh_offset;
1052                                 } else {
1053                                         curr_map->map_ip = identity__map_ip;
1054                                         curr_map->unmap_ip = identity__map_ip;
1055                                 }
1056                                 curr_dso->symtab_type = dso->symtab_type;
1057                                 map_groups__insert(kmaps, curr_map);
1058                                 /*
1059                                  * Add it before we drop the referece to curr_map,
1060                                  * i.e. while we still are sure to have a reference
1061                                  * to this DSO via curr_map->dso.
1062                                  */
1063                                 dsos__add(&map->groups->machine->dsos, curr_dso);
1064                                 /* kmaps already got it */
1065                                 map__put(curr_map);
1066                                 dso__set_loaded(curr_dso, map->type);
1067                         } else
1068                                 curr_dso = curr_map->dso;
1069
1070                         goto new_symbol;
1071                 }
1072
1073                 if ((used_opd && runtime_ss->adjust_symbols)
1074                                 || (!used_opd && syms_ss->adjust_symbols)) {
1075                         pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1076                                   "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
1077                                   (u64)sym.st_value, (u64)shdr.sh_addr,
1078                                   (u64)shdr.sh_offset);
1079                         sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1080                 }
1081 new_symbol:
1082                 demangled = demangle_sym(dso, kmodule, elf_name);
1083                 if (demangled != NULL)
1084                         elf_name = demangled;
1085
1086                 f = symbol__new(sym.st_value, sym.st_size,
1087                                 GELF_ST_BIND(sym.st_info), elf_name);
1088                 free(demangled);
1089                 if (!f)
1090                         goto out_elf_end;
1091
1092                 arch__sym_update(f, &sym);
1093
1094                 __symbols__insert(&curr_dso->symbols[curr_map->type], f, dso->kernel);
1095                 nr++;
1096         }
1097
1098         /*
1099          * For misannotated, zeroed, ASM function sizes.
1100          */
1101         if (nr > 0) {
1102                 symbols__fixup_end(&dso->symbols[map->type]);
1103                 symbols__fixup_duplicate(&dso->symbols[map->type]);
1104                 if (kmap) {
1105                         /*
1106                          * We need to fixup this here too because we create new
1107                          * maps here, for things like vsyscall sections.
1108                          */
1109                         __map_groups__fixup_end(kmaps, map->type);
1110                 }
1111         }
1112         err = nr;
1113 out_elf_end:
1114         return err;
1115 }
1116
1117 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1118 {
1119         GElf_Phdr phdr;
1120         size_t i, phdrnum;
1121         int err;
1122         u64 sz;
1123
1124         if (elf_getphdrnum(elf, &phdrnum))
1125                 return -1;
1126
1127         for (i = 0; i < phdrnum; i++) {
1128                 if (gelf_getphdr(elf, i, &phdr) == NULL)
1129                         return -1;
1130                 if (phdr.p_type != PT_LOAD)
1131                         continue;
1132                 if (exe) {
1133                         if (!(phdr.p_flags & PF_X))
1134                                 continue;
1135                 } else {
1136                         if (!(phdr.p_flags & PF_R))
1137                                 continue;
1138                 }
1139                 sz = min(phdr.p_memsz, phdr.p_filesz);
1140                 if (!sz)
1141                         continue;
1142                 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1143                 if (err)
1144                         return err;
1145         }
1146         return 0;
1147 }
1148
1149 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1150                     bool *is_64_bit)
1151 {
1152         int err;
1153         Elf *elf;
1154
1155         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1156         if (elf == NULL)
1157                 return -1;
1158
1159         if (is_64_bit)
1160                 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1161
1162         err = elf_read_maps(elf, exe, mapfn, data);
1163
1164         elf_end(elf);
1165         return err;
1166 }
1167
1168 enum dso_type dso__type_fd(int fd)
1169 {
1170         enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1171         GElf_Ehdr ehdr;
1172         Elf_Kind ek;
1173         Elf *elf;
1174
1175         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1176         if (elf == NULL)
1177                 goto out;
1178
1179         ek = elf_kind(elf);
1180         if (ek != ELF_K_ELF)
1181                 goto out_end;
1182
1183         if (gelf_getclass(elf) == ELFCLASS64) {
1184                 dso_type = DSO__TYPE_64BIT;
1185                 goto out_end;
1186         }
1187
1188         if (gelf_getehdr(elf, &ehdr) == NULL)
1189                 goto out_end;
1190
1191         if (ehdr.e_machine == EM_X86_64)
1192                 dso_type = DSO__TYPE_X32BIT;
1193         else
1194                 dso_type = DSO__TYPE_32BIT;
1195 out_end:
1196         elf_end(elf);
1197 out:
1198         return dso_type;
1199 }
1200
1201 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1202 {
1203         ssize_t r;
1204         size_t n;
1205         int err = -1;
1206         char *buf = malloc(page_size);
1207
1208         if (buf == NULL)
1209                 return -1;
1210
1211         if (lseek(to, to_offs, SEEK_SET) != to_offs)
1212                 goto out;
1213
1214         if (lseek(from, from_offs, SEEK_SET) != from_offs)
1215                 goto out;
1216
1217         while (len) {
1218                 n = page_size;
1219                 if (len < n)
1220                         n = len;
1221                 /* Use read because mmap won't work on proc files */
1222                 r = read(from, buf, n);
1223                 if (r < 0)
1224                         goto out;
1225                 if (!r)
1226                         break;
1227                 n = r;
1228                 r = write(to, buf, n);
1229                 if (r < 0)
1230                         goto out;
1231                 if ((size_t)r != n)
1232                         goto out;
1233                 len -= n;
1234         }
1235
1236         err = 0;
1237 out:
1238         free(buf);
1239         return err;
1240 }
1241
1242 struct kcore {
1243         int fd;
1244         int elfclass;
1245         Elf *elf;
1246         GElf_Ehdr ehdr;
1247 };
1248
1249 static int kcore__open(struct kcore *kcore, const char *filename)
1250 {
1251         GElf_Ehdr *ehdr;
1252
1253         kcore->fd = open(filename, O_RDONLY);
1254         if (kcore->fd == -1)
1255                 return -1;
1256
1257         kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1258         if (!kcore->elf)
1259                 goto out_close;
1260
1261         kcore->elfclass = gelf_getclass(kcore->elf);
1262         if (kcore->elfclass == ELFCLASSNONE)
1263                 goto out_end;
1264
1265         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1266         if (!ehdr)
1267                 goto out_end;
1268
1269         return 0;
1270
1271 out_end:
1272         elf_end(kcore->elf);
1273 out_close:
1274         close(kcore->fd);
1275         return -1;
1276 }
1277
1278 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1279                        bool temp)
1280 {
1281         kcore->elfclass = elfclass;
1282
1283         if (temp)
1284                 kcore->fd = mkstemp(filename);
1285         else
1286                 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1287         if (kcore->fd == -1)
1288                 return -1;
1289
1290         kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1291         if (!kcore->elf)
1292                 goto out_close;
1293
1294         if (!gelf_newehdr(kcore->elf, elfclass))
1295                 goto out_end;
1296
1297         memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
1298
1299         return 0;
1300
1301 out_end:
1302         elf_end(kcore->elf);
1303 out_close:
1304         close(kcore->fd);
1305         unlink(filename);
1306         return -1;
1307 }
1308
1309 static void kcore__close(struct kcore *kcore)
1310 {
1311         elf_end(kcore->elf);
1312         close(kcore->fd);
1313 }
1314
1315 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1316 {
1317         GElf_Ehdr *ehdr = &to->ehdr;
1318         GElf_Ehdr *kehdr = &from->ehdr;
1319
1320         memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1321         ehdr->e_type      = kehdr->e_type;
1322         ehdr->e_machine   = kehdr->e_machine;
1323         ehdr->e_version   = kehdr->e_version;
1324         ehdr->e_entry     = 0;
1325         ehdr->e_shoff     = 0;
1326         ehdr->e_flags     = kehdr->e_flags;
1327         ehdr->e_phnum     = count;
1328         ehdr->e_shentsize = 0;
1329         ehdr->e_shnum     = 0;
1330         ehdr->e_shstrndx  = 0;
1331
1332         if (from->elfclass == ELFCLASS32) {
1333                 ehdr->e_phoff     = sizeof(Elf32_Ehdr);
1334                 ehdr->e_ehsize    = sizeof(Elf32_Ehdr);
1335                 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1336         } else {
1337                 ehdr->e_phoff     = sizeof(Elf64_Ehdr);
1338                 ehdr->e_ehsize    = sizeof(Elf64_Ehdr);
1339                 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1340         }
1341
1342         if (!gelf_update_ehdr(to->elf, ehdr))
1343                 return -1;
1344
1345         if (!gelf_newphdr(to->elf, count))
1346                 return -1;
1347
1348         return 0;
1349 }
1350
1351 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1352                            u64 addr, u64 len)
1353 {
1354         GElf_Phdr phdr = {
1355                 .p_type         = PT_LOAD,
1356                 .p_flags        = PF_R | PF_W | PF_X,
1357                 .p_offset       = offset,
1358                 .p_vaddr        = addr,
1359                 .p_paddr        = 0,
1360                 .p_filesz       = len,
1361                 .p_memsz        = len,
1362                 .p_align        = page_size,
1363         };
1364
1365         if (!gelf_update_phdr(kcore->elf, idx, &phdr))
1366                 return -1;
1367
1368         return 0;
1369 }
1370
1371 static off_t kcore__write(struct kcore *kcore)
1372 {
1373         return elf_update(kcore->elf, ELF_C_WRITE);
1374 }
1375
1376 struct phdr_data {
1377         off_t offset;
1378         u64 addr;
1379         u64 len;
1380 };
1381
1382 struct kcore_copy_info {
1383         u64 stext;
1384         u64 etext;
1385         u64 first_symbol;
1386         u64 last_symbol;
1387         u64 first_module;
1388         u64 last_module_symbol;
1389         struct phdr_data kernel_map;
1390         struct phdr_data modules_map;
1391 };
1392
1393 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1394                                         u64 start)
1395 {
1396         struct kcore_copy_info *kci = arg;
1397
1398         if (!symbol_type__is_a(type, MAP__FUNCTION))
1399                 return 0;
1400
1401         if (strchr(name, '[')) {
1402                 if (start > kci->last_module_symbol)
1403                         kci->last_module_symbol = start;
1404                 return 0;
1405         }
1406
1407         if (!kci->first_symbol || start < kci->first_symbol)
1408                 kci->first_symbol = start;
1409
1410         if (!kci->last_symbol || start > kci->last_symbol)
1411                 kci->last_symbol = start;
1412
1413         if (!strcmp(name, "_stext")) {
1414                 kci->stext = start;
1415                 return 0;
1416         }
1417
1418         if (!strcmp(name, "_etext")) {
1419                 kci->etext = start;
1420                 return 0;
1421         }
1422
1423         return 0;
1424 }
1425
1426 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1427                                       const char *dir)
1428 {
1429         char kallsyms_filename[PATH_MAX];
1430
1431         scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1432
1433         if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1434                 return -1;
1435
1436         if (kallsyms__parse(kallsyms_filename, kci,
1437                             kcore_copy__process_kallsyms) < 0)
1438                 return -1;
1439
1440         return 0;
1441 }
1442
1443 static int kcore_copy__process_modules(void *arg,
1444                                        const char *name __maybe_unused,
1445                                        u64 start)
1446 {
1447         struct kcore_copy_info *kci = arg;
1448
1449         if (!kci->first_module || start < kci->first_module)
1450                 kci->first_module = start;
1451
1452         return 0;
1453 }
1454
1455 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1456                                      const char *dir)
1457 {
1458         char modules_filename[PATH_MAX];
1459
1460         scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1461
1462         if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1463                 return -1;
1464
1465         if (modules__parse(modules_filename, kci,
1466                            kcore_copy__process_modules) < 0)
1467                 return -1;
1468
1469         return 0;
1470 }
1471
1472 static void kcore_copy__map(struct phdr_data *p, u64 start, u64 end, u64 pgoff,
1473                             u64 s, u64 e)
1474 {
1475         if (p->addr || s < start || s >= end)
1476                 return;
1477
1478         p->addr = s;
1479         p->offset = (s - start) + pgoff;
1480         p->len = e < end ? e - s : end - s;
1481 }
1482
1483 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1484 {
1485         struct kcore_copy_info *kci = data;
1486         u64 end = start + len;
1487
1488         kcore_copy__map(&kci->kernel_map, start, end, pgoff, kci->stext,
1489                         kci->etext);
1490
1491         kcore_copy__map(&kci->modules_map, start, end, pgoff, kci->first_module,
1492                         kci->last_module_symbol);
1493
1494         return 0;
1495 }
1496
1497 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1498 {
1499         if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1500                 return -1;
1501
1502         return 0;
1503 }
1504
1505 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1506                                  Elf *elf)
1507 {
1508         if (kcore_copy__parse_kallsyms(kci, dir))
1509                 return -1;
1510
1511         if (kcore_copy__parse_modules(kci, dir))
1512                 return -1;
1513
1514         if (kci->stext)
1515                 kci->stext = round_down(kci->stext, page_size);
1516         else
1517                 kci->stext = round_down(kci->first_symbol, page_size);
1518
1519         if (kci->etext) {
1520                 kci->etext = round_up(kci->etext, page_size);
1521         } else if (kci->last_symbol) {
1522                 kci->etext = round_up(kci->last_symbol, page_size);
1523                 kci->etext += page_size;
1524         }
1525
1526         kci->first_module = round_down(kci->first_module, page_size);
1527
1528         if (kci->last_module_symbol) {
1529                 kci->last_module_symbol = round_up(kci->last_module_symbol,
1530                                                    page_size);
1531                 kci->last_module_symbol += page_size;
1532         }
1533
1534         if (!kci->stext || !kci->etext)
1535                 return -1;
1536
1537         if (kci->first_module && !kci->last_module_symbol)
1538                 return -1;
1539
1540         return kcore_copy__read_maps(kci, elf);
1541 }
1542
1543 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1544                                  const char *name)
1545 {
1546         char from_filename[PATH_MAX];
1547         char to_filename[PATH_MAX];
1548
1549         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1550         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1551
1552         return copyfile_mode(from_filename, to_filename, 0400);
1553 }
1554
1555 static int kcore_copy__unlink(const char *dir, const char *name)
1556 {
1557         char filename[PATH_MAX];
1558
1559         scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1560
1561         return unlink(filename);
1562 }
1563
1564 static int kcore_copy__compare_fds(int from, int to)
1565 {
1566         char *buf_from;
1567         char *buf_to;
1568         ssize_t ret;
1569         size_t len;
1570         int err = -1;
1571
1572         buf_from = malloc(page_size);
1573         buf_to = malloc(page_size);
1574         if (!buf_from || !buf_to)
1575                 goto out;
1576
1577         while (1) {
1578                 /* Use read because mmap won't work on proc files */
1579                 ret = read(from, buf_from, page_size);
1580                 if (ret < 0)
1581                         goto out;
1582
1583                 if (!ret)
1584                         break;
1585
1586                 len = ret;
1587
1588                 if (readn(to, buf_to, len) != (int)len)
1589                         goto out;
1590
1591                 if (memcmp(buf_from, buf_to, len))
1592                         goto out;
1593         }
1594
1595         err = 0;
1596 out:
1597         free(buf_to);
1598         free(buf_from);
1599         return err;
1600 }
1601
1602 static int kcore_copy__compare_files(const char *from_filename,
1603                                      const char *to_filename)
1604 {
1605         int from, to, err = -1;
1606
1607         from = open(from_filename, O_RDONLY);
1608         if (from < 0)
1609                 return -1;
1610
1611         to = open(to_filename, O_RDONLY);
1612         if (to < 0)
1613                 goto out_close_from;
1614
1615         err = kcore_copy__compare_fds(from, to);
1616
1617         close(to);
1618 out_close_from:
1619         close(from);
1620         return err;
1621 }
1622
1623 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
1624                                     const char *name)
1625 {
1626         char from_filename[PATH_MAX];
1627         char to_filename[PATH_MAX];
1628
1629         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1630         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1631
1632         return kcore_copy__compare_files(from_filename, to_filename);
1633 }
1634
1635 /**
1636  * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1637  * @from_dir: from directory
1638  * @to_dir: to directory
1639  *
1640  * This function copies kallsyms, modules and kcore files from one directory to
1641  * another.  kallsyms and modules are copied entirely.  Only code segments are
1642  * copied from kcore.  It is assumed that two segments suffice: one for the
1643  * kernel proper and one for all the modules.  The code segments are determined
1644  * from kallsyms and modules files.  The kernel map starts at _stext or the
1645  * lowest function symbol, and ends at _etext or the highest function symbol.
1646  * The module map starts at the lowest module address and ends at the highest
1647  * module symbol.  Start addresses are rounded down to the nearest page.  End
1648  * addresses are rounded up to the nearest page.  An extra page is added to the
1649  * highest kernel symbol and highest module symbol to, hopefully, encompass that
1650  * symbol too.  Because it contains only code sections, the resulting kcore is
1651  * unusual.  One significant peculiarity is that the mapping (start -> pgoff)
1652  * is not the same for the kernel map and the modules map.  That happens because
1653  * the data is copied adjacently whereas the original kcore has gaps.  Finally,
1654  * kallsyms and modules files are compared with their copies to check that
1655  * modules have not been loaded or unloaded while the copies were taking place.
1656  *
1657  * Return: %0 on success, %-1 on failure.
1658  */
1659 int kcore_copy(const char *from_dir, const char *to_dir)
1660 {
1661         struct kcore kcore;
1662         struct kcore extract;
1663         size_t count = 2;
1664         int idx = 0, err = -1;
1665         off_t offset = page_size, sz, modules_offset = 0;
1666         struct kcore_copy_info kci = { .stext = 0, };
1667         char kcore_filename[PATH_MAX];
1668         char extract_filename[PATH_MAX];
1669
1670         if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
1671                 return -1;
1672
1673         if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
1674                 goto out_unlink_kallsyms;
1675
1676         scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
1677         scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
1678
1679         if (kcore__open(&kcore, kcore_filename))
1680                 goto out_unlink_modules;
1681
1682         if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
1683                 goto out_kcore_close;
1684
1685         if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
1686                 goto out_kcore_close;
1687
1688         if (!kci.modules_map.addr)
1689                 count -= 1;
1690
1691         if (kcore__copy_hdr(&kcore, &extract, count))
1692                 goto out_extract_close;
1693
1694         if (kcore__add_phdr(&extract, idx++, offset, kci.kernel_map.addr,
1695                             kci.kernel_map.len))
1696                 goto out_extract_close;
1697
1698         if (kci.modules_map.addr) {
1699                 modules_offset = offset + kci.kernel_map.len;
1700                 if (kcore__add_phdr(&extract, idx, modules_offset,
1701                                     kci.modules_map.addr, kci.modules_map.len))
1702                         goto out_extract_close;
1703         }
1704
1705         sz = kcore__write(&extract);
1706         if (sz < 0 || sz > offset)
1707                 goto out_extract_close;
1708
1709         if (copy_bytes(kcore.fd, kci.kernel_map.offset, extract.fd, offset,
1710                        kci.kernel_map.len))
1711                 goto out_extract_close;
1712
1713         if (modules_offset && copy_bytes(kcore.fd, kci.modules_map.offset,
1714                                          extract.fd, modules_offset,
1715                                          kci.modules_map.len))
1716                 goto out_extract_close;
1717
1718         if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
1719                 goto out_extract_close;
1720
1721         if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
1722                 goto out_extract_close;
1723
1724         err = 0;
1725
1726 out_extract_close:
1727         kcore__close(&extract);
1728         if (err)
1729                 unlink(extract_filename);
1730 out_kcore_close:
1731         kcore__close(&kcore);
1732 out_unlink_modules:
1733         if (err)
1734                 kcore_copy__unlink(to_dir, "modules");
1735 out_unlink_kallsyms:
1736         if (err)
1737                 kcore_copy__unlink(to_dir, "kallsyms");
1738
1739         return err;
1740 }
1741
1742 int kcore_extract__create(struct kcore_extract *kce)
1743 {
1744         struct kcore kcore;
1745         struct kcore extract;
1746         size_t count = 1;
1747         int idx = 0, err = -1;
1748         off_t offset = page_size, sz;
1749
1750         if (kcore__open(&kcore, kce->kcore_filename))
1751                 return -1;
1752
1753         strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
1754         if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
1755                 goto out_kcore_close;
1756
1757         if (kcore__copy_hdr(&kcore, &extract, count))
1758                 goto out_extract_close;
1759
1760         if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
1761                 goto out_extract_close;
1762
1763         sz = kcore__write(&extract);
1764         if (sz < 0 || sz > offset)
1765                 goto out_extract_close;
1766
1767         if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
1768                 goto out_extract_close;
1769
1770         err = 0;
1771
1772 out_extract_close:
1773         kcore__close(&extract);
1774         if (err)
1775                 unlink(kce->extract_filename);
1776 out_kcore_close:
1777         kcore__close(&kcore);
1778
1779         return err;
1780 }
1781
1782 void kcore_extract__delete(struct kcore_extract *kce)
1783 {
1784         unlink(kce->extract_filename);
1785 }
1786
1787 #ifdef HAVE_GELF_GETNOTE_SUPPORT
1788 /**
1789  * populate_sdt_note : Parse raw data and identify SDT note
1790  * @elf: elf of the opened file
1791  * @data: raw data of a section with description offset applied
1792  * @len: note description size
1793  * @type: type of the note
1794  * @sdt_notes: List to add the SDT note
1795  *
1796  * Responsible for parsing the @data in section .note.stapsdt in @elf and
1797  * if its an SDT note, it appends to @sdt_notes list.
1798  */
1799 static int populate_sdt_note(Elf **elf, const char *data, size_t len,
1800                              struct list_head *sdt_notes)
1801 {
1802         const char *provider, *name, *args;
1803         struct sdt_note *tmp = NULL;
1804         GElf_Ehdr ehdr;
1805         GElf_Addr base_off = 0;
1806         GElf_Shdr shdr;
1807         int ret = -EINVAL;
1808
1809         union {
1810                 Elf64_Addr a64[NR_ADDR];
1811                 Elf32_Addr a32[NR_ADDR];
1812         } buf;
1813
1814         Elf_Data dst = {
1815                 .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
1816                 .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),
1817                 .d_off = 0, .d_align = 0
1818         };
1819         Elf_Data src = {
1820                 .d_buf = (void *) data, .d_type = ELF_T_ADDR,
1821                 .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
1822                 .d_align = 0
1823         };
1824
1825         tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
1826         if (!tmp) {
1827                 ret = -ENOMEM;
1828                 goto out_err;
1829         }
1830
1831         INIT_LIST_HEAD(&tmp->note_list);
1832
1833         if (len < dst.d_size + 3)
1834                 goto out_free_note;
1835
1836         /* Translation from file representation to memory representation */
1837         if (gelf_xlatetom(*elf, &dst, &src,
1838                           elf_getident(*elf, NULL)[EI_DATA]) == NULL) {
1839                 pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
1840                 goto out_free_note;
1841         }
1842
1843         /* Populate the fields of sdt_note */
1844         provider = data + dst.d_size;
1845
1846         name = (const char *)memchr(provider, '\0', data + len - provider);
1847         if (name++ == NULL)
1848                 goto out_free_note;
1849
1850         tmp->provider = strdup(provider);
1851         if (!tmp->provider) {
1852                 ret = -ENOMEM;
1853                 goto out_free_note;
1854         }
1855         tmp->name = strdup(name);
1856         if (!tmp->name) {
1857                 ret = -ENOMEM;
1858                 goto out_free_prov;
1859         }
1860
1861         args = memchr(name, '\0', data + len - name);
1862
1863         /*
1864          * There is no argument if:
1865          * - We reached the end of the note;
1866          * - There is not enough room to hold a potential string;
1867          * - The argument string is empty or just contains ':'.
1868          */
1869         if (args == NULL || data + len - args < 2 ||
1870                 args[1] == ':' || args[1] == '\0')
1871                 tmp->args = NULL;
1872         else {
1873                 tmp->args = strdup(++args);
1874                 if (!tmp->args) {
1875                         ret = -ENOMEM;
1876                         goto out_free_name;
1877                 }
1878         }
1879
1880         if (gelf_getclass(*elf) == ELFCLASS32) {
1881                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
1882                 tmp->bit32 = true;
1883         } else {
1884                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
1885                 tmp->bit32 = false;
1886         }
1887
1888         if (!gelf_getehdr(*elf, &ehdr)) {
1889                 pr_debug("%s : cannot get elf header.\n", __func__);
1890                 ret = -EBADF;
1891                 goto out_free_args;
1892         }
1893
1894         /* Adjust the prelink effect :
1895          * Find out the .stapsdt.base section.
1896          * This scn will help us to handle prelinking (if present).
1897          * Compare the retrieved file offset of the base section with the
1898          * base address in the description of the SDT note. If its different,
1899          * then accordingly, adjust the note location.
1900          */
1901         if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL)) {
1902                 base_off = shdr.sh_offset;
1903                 if (base_off) {
1904                         if (tmp->bit32)
1905                                 tmp->addr.a32[0] = tmp->addr.a32[0] + base_off -
1906                                         tmp->addr.a32[1];
1907                         else
1908                                 tmp->addr.a64[0] = tmp->addr.a64[0] + base_off -
1909                                         tmp->addr.a64[1];
1910                 }
1911         }
1912
1913         list_add_tail(&tmp->note_list, sdt_notes);
1914         return 0;
1915
1916 out_free_args:
1917         free(tmp->args);
1918 out_free_name:
1919         free(tmp->name);
1920 out_free_prov:
1921         free(tmp->provider);
1922 out_free_note:
1923         free(tmp);
1924 out_err:
1925         return ret;
1926 }
1927
1928 /**
1929  * construct_sdt_notes_list : constructs a list of SDT notes
1930  * @elf : elf to look into
1931  * @sdt_notes : empty list_head
1932  *
1933  * Scans the sections in 'elf' for the section
1934  * .note.stapsdt. It, then calls populate_sdt_note to find
1935  * out the SDT events and populates the 'sdt_notes'.
1936  */
1937 static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
1938 {
1939         GElf_Ehdr ehdr;
1940         Elf_Scn *scn = NULL;
1941         Elf_Data *data;
1942         GElf_Shdr shdr;
1943         size_t shstrndx, next;
1944         GElf_Nhdr nhdr;
1945         size_t name_off, desc_off, offset;
1946         int ret = 0;
1947
1948         if (gelf_getehdr(elf, &ehdr) == NULL) {
1949                 ret = -EBADF;
1950                 goto out_ret;
1951         }
1952         if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
1953                 ret = -EBADF;
1954                 goto out_ret;
1955         }
1956
1957         /* Look for the required section */
1958         scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
1959         if (!scn) {
1960                 ret = -ENOENT;
1961                 goto out_ret;
1962         }
1963
1964         if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
1965                 ret = -ENOENT;
1966                 goto out_ret;
1967         }
1968
1969         data = elf_getdata(scn, NULL);
1970
1971         /* Get the SDT notes */
1972         for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
1973                                               &desc_off)) > 0; offset = next) {
1974                 if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
1975                     !memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
1976                             sizeof(SDT_NOTE_NAME))) {
1977                         /* Check the type of the note */
1978                         if (nhdr.n_type != SDT_NOTE_TYPE)
1979                                 goto out_ret;
1980
1981                         ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
1982                                                 nhdr.n_descsz, sdt_notes);
1983                         if (ret < 0)
1984                                 goto out_ret;
1985                 }
1986         }
1987         if (list_empty(sdt_notes))
1988                 ret = -ENOENT;
1989
1990 out_ret:
1991         return ret;
1992 }
1993
1994 /**
1995  * get_sdt_note_list : Wrapper to construct a list of sdt notes
1996  * @head : empty list_head
1997  * @target : file to find SDT notes from
1998  *
1999  * This opens the file, initializes
2000  * the ELF and then calls construct_sdt_notes_list.
2001  */
2002 int get_sdt_note_list(struct list_head *head, const char *target)
2003 {
2004         Elf *elf;
2005         int fd, ret;
2006
2007         fd = open(target, O_RDONLY);
2008         if (fd < 0)
2009                 return -EBADF;
2010
2011         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
2012         if (!elf) {
2013                 ret = -EBADF;
2014                 goto out_close;
2015         }
2016         ret = construct_sdt_notes_list(elf, head);
2017         elf_end(elf);
2018 out_close:
2019         close(fd);
2020         return ret;
2021 }
2022
2023 /**
2024  * cleanup_sdt_note_list : free the sdt notes' list
2025  * @sdt_notes: sdt notes' list
2026  *
2027  * Free up the SDT notes in @sdt_notes.
2028  * Returns the number of SDT notes free'd.
2029  */
2030 int cleanup_sdt_note_list(struct list_head *sdt_notes)
2031 {
2032         struct sdt_note *tmp, *pos;
2033         int nr_free = 0;
2034
2035         list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
2036                 list_del(&pos->note_list);
2037                 free(pos->name);
2038                 free(pos->provider);
2039                 free(pos);
2040                 nr_free++;
2041         }
2042         return nr_free;
2043 }
2044
2045 /**
2046  * sdt_notes__get_count: Counts the number of sdt events
2047  * @start: list_head to sdt_notes list
2048  *
2049  * Returns the number of SDT notes in a list
2050  */
2051 int sdt_notes__get_count(struct list_head *start)
2052 {
2053         struct sdt_note *sdt_ptr;
2054         int count = 0;
2055
2056         list_for_each_entry(sdt_ptr, start, note_list)
2057                 count++;
2058         return count;
2059 }
2060 #endif
2061
2062 void symbol__elf_init(void)
2063 {
2064         elf_version(EV_CURRENT);
2065 }