arch/x86/tools/relocs.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* This is included from relocs_32/64.c */
   3
   4 #define ElfW(type)              _ElfW(ELF_BITS, type)
   5 #define _ElfW(bits, type)       __ElfW(bits, type)
   6 #define __ElfW(bits, type)      Elf##bits##_##type
   7
   8 #define Elf_Addr                ElfW(Addr)
   9 #define Elf_Ehdr                ElfW(Ehdr)
  10 #define Elf_Phdr                ElfW(Phdr)
  11 #define Elf_Shdr                ElfW(Shdr)
  12 #define Elf_Sym                 ElfW(Sym)
  13
  14 static Elf_Ehdr         ehdr;
  15 static unsigned long    shnum;
  16 static unsigned int     shstrndx;
  17 static unsigned int     shsymtabndx;
  18 static unsigned int     shxsymtabndx;
  19
  20 static int sym_index(Elf_Sym *sym);
  21
  22 struct relocs {
  23         uint32_t        *offset;
  24         unsigned long   count;
  25         unsigned long   size;
  26 };
  27
  28 static struct relocs relocs16;
  29 static struct relocs relocs32;
  30 #if ELF_BITS == 64
  31 static struct relocs relocs32neg;
  32 static struct relocs relocs64;
  33 #define FMT PRIu64
  34 #else
  35 #define FMT PRIu32
  36 #endif
  37
  38 struct section {
  39         Elf_Shdr       shdr;
  40         struct section *link;
  41         Elf_Sym        *symtab;
  42         Elf32_Word     *xsymtab;
  43         Elf_Rel        *reltab;
  44         char           *strtab;
  45 };
  46 static struct section *secs;
  47
  48 static const char * const sym_regex_kernel[S_NSYMTYPES] = {
  49 /*
  50  * Following symbols have been audited. There values are constant and do
  51  * not change if bzImage is loaded at a different physical address than
  52  * the address for which it has been compiled. Don't warn user about
  53  * absolute relocations present w.r.t these symbols.
  54  */
  55         [S_ABS] =
  56         "^(xen_irq_disable_direct_reloc$|"
  57         "xen_save_fl_direct_reloc$|"
  58         "VDSO|"
  59         "__crc_)",
  60
  61 /*
  62  * These symbols are known to be relative, even if the linker marks them
  63  * as absolute (typically defined outside any section in the linker script.)
  64  */
  65         [S_REL] =
  66         "^(__init_(begin|end)|"
  67         "__x86_cpu_dev_(start|end)|"
  68         "(__parainstructions|__alt_instructions)(_end)?|"
  69         "(__iommu_table|__apicdrivers|__smp_locks)(_end)?|"
  70         "__(start|end)_pci_.*|"
  71 #if CONFIG_FW_LOADER
  72         "__(start|end)_builtin_fw|"
  73 #endif
  74         "__(start|stop)___ksymtab(_gpl)?|"
  75         "__(start|stop)___kcrctab(_gpl)?|"
  76         "__(start|stop)___param|"
  77         "__(start|stop)___modver|"
  78         "__(start|stop)___bug_table|"
  79         "__tracedata_(start|end)|"
  80         "__(start|stop)_notes|"
  81         "__end_rodata|"
  82         "__end_rodata_aligned|"
  83         "__initramfs_start|"
  84         "(jiffies|jiffies_64)|"
  85 #if ELF_BITS == 64
  86         "__per_cpu_load|"
  87         "init_per_cpu__.*|"
  88         "__end_rodata_hpage_align|"
  89 #endif
  90         "__vvar_page|"
  91         "_end)$"
  92 };
  93
  94
  95 static const char * const sym_regex_realmode[S_NSYMTYPES] = {
  96 /*
  97  * These symbols are known to be relative, even if the linker marks them
  98  * as absolute (typically defined outside any section in the linker script.)
  99  */
 100         [S_REL] =
 101         "^pa_",
 102
 103 /*
 104  * These are 16-bit segment symbols when compiling 16-bit code.
 105  */
 106         [S_SEG] =
 107         "^real_mode_seg$",
 108
 109 /*
 110  * These are offsets belonging to segments, as opposed to linear addresses,
 111  * when compiling 16-bit code.
 112  */
 113         [S_LIN] =
 114         "^pa_",
 115 };
 116
 117 static const char * const *sym_regex;
 118
 119 static regex_t sym_regex_c[S_NSYMTYPES];
 120 static int is_reloc(enum symtype type, const char *sym_name)
 121 {
 122         return sym_regex[type] &&
 123                 !regexec(&sym_regex_c[type], sym_name, 0, NULL, 0);
 124 }
 125
 126 static void regex_init(int use_real_mode)
 127 {
 128         char errbuf[128];
 129         int err;
 130         int i;
 131
 132         if (use_real_mode)
 133                 sym_regex = sym_regex_realmode;
 134         else
 135                 sym_regex = sym_regex_kernel;
 136
 137         for (i = 0; i < S_NSYMTYPES; i++) {
 138                 if (!sym_regex[i])
 139                         continue;
 140
 141                 err = regcomp(&sym_regex_c[i], sym_regex[i],
 142                               REG_EXTENDED|REG_NOSUB);
 143
 144                 if (err) {
 145                         regerror(err, &sym_regex_c[i], errbuf, sizeof(errbuf));
 146                         die("%s", errbuf);
 147                 }
 148         }
 149 }
 150
 151 static const char *sym_type(unsigned type)
 152 {
 153         static const char *type_name[] = {
 154 #define SYM_TYPE(X) [X] = #X
 155                 SYM_TYPE(STT_NOTYPE),
 156                 SYM_TYPE(STT_OBJECT),
 157                 SYM_TYPE(STT_FUNC),
 158                 SYM_TYPE(STT_SECTION),
 159                 SYM_TYPE(STT_FILE),
 160                 SYM_TYPE(STT_COMMON),
 161                 SYM_TYPE(STT_TLS),
 162 #undef SYM_TYPE
 163         };
 164         const char *name = "unknown sym type name";
 165         if (type < ARRAY_SIZE(type_name)) {
 166                 name = type_name[type];
 167         }
 168         return name;
 169 }
 170
 171 static const char *sym_bind(unsigned bind)
 172 {
 173         static const char *bind_name[] = {
 174 #define SYM_BIND(X) [X] = #X
 175                 SYM_BIND(STB_LOCAL),
 176                 SYM_BIND(STB_GLOBAL),
 177                 SYM_BIND(STB_WEAK),
 178 #undef SYM_BIND
 179         };
 180         const char *name = "unknown sym bind name";
 181         if (bind < ARRAY_SIZE(bind_name)) {
 182                 name = bind_name[bind];
 183         }
 184         return name;
 185 }
 186
 187 static const char *sym_visibility(unsigned visibility)
 188 {
 189         static const char *visibility_name[] = {
 190 #define SYM_VISIBILITY(X) [X] = #X
 191                 SYM_VISIBILITY(STV_DEFAULT),
 192                 SYM_VISIBILITY(STV_INTERNAL),
 193                 SYM_VISIBILITY(STV_HIDDEN),
 194                 SYM_VISIBILITY(STV_PROTECTED),
 195 #undef SYM_VISIBILITY
 196         };
 197         const char *name = "unknown sym visibility name";
 198         if (visibility < ARRAY_SIZE(visibility_name)) {
 199                 name = visibility_name[visibility];
 200         }
 201         return name;
 202 }
 203
 204 static const char *rel_type(unsigned type)
 205 {
 206         static const char *type_name[] = {
 207 #define REL_TYPE(X) [X] = #X
 208 #if ELF_BITS == 64
 209                 REL_TYPE(R_X86_64_NONE),
 210                 REL_TYPE(R_X86_64_64),
 211                 REL_TYPE(R_X86_64_PC64),
 212                 REL_TYPE(R_X86_64_PC32),
 213                 REL_TYPE(R_X86_64_GOT32),
 214                 REL_TYPE(R_X86_64_PLT32),
 215                 REL_TYPE(R_X86_64_COPY),
 216                 REL_TYPE(R_X86_64_GLOB_DAT),
 217                 REL_TYPE(R_X86_64_JUMP_SLOT),
 218                 REL_TYPE(R_X86_64_RELATIVE),
 219                 REL_TYPE(R_X86_64_GOTPCREL),
 220                 REL_TYPE(R_X86_64_32),
 221                 REL_TYPE(R_X86_64_32S),
 222                 REL_TYPE(R_X86_64_16),
 223                 REL_TYPE(R_X86_64_PC16),
 224                 REL_TYPE(R_X86_64_8),
 225                 REL_TYPE(R_X86_64_PC8),
 226 #else
 227                 REL_TYPE(R_386_NONE),
 228                 REL_TYPE(R_386_32),
 229                 REL_TYPE(R_386_PC32),
 230                 REL_TYPE(R_386_GOT32),
 231                 REL_TYPE(R_386_PLT32),
 232                 REL_TYPE(R_386_COPY),
 233                 REL_TYPE(R_386_GLOB_DAT),
 234                 REL_TYPE(R_386_JMP_SLOT),
 235                 REL_TYPE(R_386_RELATIVE),
 236                 REL_TYPE(R_386_GOTOFF),
 237                 REL_TYPE(R_386_GOTPC),
 238                 REL_TYPE(R_386_8),
 239                 REL_TYPE(R_386_PC8),
 240                 REL_TYPE(R_386_16),
 241                 REL_TYPE(R_386_PC16),
 242 #endif
 243 #undef REL_TYPE
 244         };
 245         const char *name = "unknown type rel type name";
 246         if (type < ARRAY_SIZE(type_name) && type_name[type]) {
 247                 name = type_name[type];
 248         }
 249         return name;
 250 }
 251
 252 static const char *sec_name(unsigned shndx)
 253 {
 254         const char *sec_strtab;
 255         const char *name;
 256         sec_strtab = secs[shstrndx].strtab;
 257         name = "<noname>";
 258         if (shndx < shnum) {
 259                 name = sec_strtab + secs[shndx].shdr.sh_name;
 260         }
 261         else if (shndx == SHN_ABS) {
 262                 name = "ABSOLUTE";
 263         }
 264         else if (shndx == SHN_COMMON) {
 265                 name = "COMMON";
 266         }
 267         return name;
 268 }
 269
 270 static const char *sym_name(const char *sym_strtab, Elf_Sym *sym)
 271 {
 272         const char *name;
 273         name = "<noname>";
 274         if (sym->st_name) {
 275                 name = sym_strtab + sym->st_name;
 276         }
 277         else {
 278                 name = sec_name(sym_index(sym));
 279         }
 280         return name;
 281 }
 282
 283 static Elf_Sym *sym_lookup(const char *symname)
 284 {
 285         int i;
 286         for (i = 0; i < shnum; i++) {
 287                 struct section *sec = &secs[i];
 288                 long nsyms;
 289                 char *strtab;
 290                 Elf_Sym *symtab;
 291                 Elf_Sym *sym;
 292
 293                 if (sec->shdr.sh_type != SHT_SYMTAB)
 294                         continue;
 295
 296                 nsyms = sec->shdr.sh_size/sizeof(Elf_Sym);
 297                 symtab = sec->symtab;
 298                 strtab = sec->link->strtab;
 299
 300                 for (sym = symtab; --nsyms >= 0; sym++) {
 301                         if (!sym->st_name)
 302                                 continue;
 303                         if (strcmp(symname, strtab + sym->st_name) == 0)
 304                                 return sym;
 305                 }
 306         }
 307         return 0;
 308 }
 309
 310 #if BYTE_ORDER == LITTLE_ENDIAN
 311 #define le16_to_cpu(val) (val)
 312 #define le32_to_cpu(val) (val)
 313 #define le64_to_cpu(val) (val)
 314 #endif
 315 #if BYTE_ORDER == BIG_ENDIAN
 316 #define le16_to_cpu(val) bswap_16(val)
 317 #define le32_to_cpu(val) bswap_32(val)
 318 #define le64_to_cpu(val) bswap_64(val)
 319 #endif
 320
 321 static uint16_t elf16_to_cpu(uint16_t val)
 322 {
 323         return le16_to_cpu(val);
 324 }
 325
 326 static uint32_t elf32_to_cpu(uint32_t val)
 327 {
 328         return le32_to_cpu(val);
 329 }
 330
 331 #define elf_half_to_cpu(x)      elf16_to_cpu(x)
 332 #define elf_word_to_cpu(x)      elf32_to_cpu(x)
 333
 334 #if ELF_BITS == 64
 335 static uint64_t elf64_to_cpu(uint64_t val)
 336 {
 337         return le64_to_cpu(val);
 338 }
 339 #define elf_addr_to_cpu(x)      elf64_to_cpu(x)
 340 #define elf_off_to_cpu(x)       elf64_to_cpu(x)
 341 #define elf_xword_to_cpu(x)     elf64_to_cpu(x)
 342 #else
 343 #define elf_addr_to_cpu(x)      elf32_to_cpu(x)
 344 #define elf_off_to_cpu(x)       elf32_to_cpu(x)
 345 #define elf_xword_to_cpu(x)     elf32_to_cpu(x)
 346 #endif
 347
 348 static int sym_index(Elf_Sym *sym)
 349 {
 350         Elf_Sym *symtab = secs[shsymtabndx].symtab;
 351         Elf32_Word *xsymtab = secs[shxsymtabndx].xsymtab;
 352         unsigned long offset;
 353         int index;
 354
 355         if (sym->st_shndx != SHN_XINDEX)
 356                 return sym->st_shndx;
 357
 358         /* calculate offset of sym from head of table. */
 359         offset = (unsigned long)sym - (unsigned long)symtab;
 360         index = offset / sizeof(*sym);
 361
 362         return elf32_to_cpu(xsymtab[index]);
 363 }
 364
 365 static void read_ehdr(FILE *fp)
 366 {
 367         if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
 368                 die("Cannot read ELF header: %s\n",
 369                         strerror(errno));
 370         }
 371         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) {
 372                 die("No ELF magic\n");
 373         }
 374         if (ehdr.e_ident[EI_CLASS] != ELF_CLASS) {
 375                 die("Not a %d bit executable\n", ELF_BITS);
 376         }
 377         if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
 378                 die("Not a LSB ELF executable\n");
 379         }
 380         if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
 381                 die("Unknown ELF version\n");
 382         }
 383         /* Convert the fields to native endian */
 384         ehdr.e_type      = elf_half_to_cpu(ehdr.e_type);
 385         ehdr.e_machine   = elf_half_to_cpu(ehdr.e_machine);
 386         ehdr.e_version   = elf_word_to_cpu(ehdr.e_version);
 387         ehdr.e_entry     = elf_addr_to_cpu(ehdr.e_entry);
 388         ehdr.e_phoff     = elf_off_to_cpu(ehdr.e_phoff);
 389         ehdr.e_shoff     = elf_off_to_cpu(ehdr.e_shoff);
 390         ehdr.e_flags     = elf_word_to_cpu(ehdr.e_flags);
 391         ehdr.e_ehsize    = elf_half_to_cpu(ehdr.e_ehsize);
 392         ehdr.e_phentsize = elf_half_to_cpu(ehdr.e_phentsize);
 393         ehdr.e_phnum     = elf_half_to_cpu(ehdr.e_phnum);
 394         ehdr.e_shentsize = elf_half_to_cpu(ehdr.e_shentsize);
 395         ehdr.e_shnum     = elf_half_to_cpu(ehdr.e_shnum);
 396         ehdr.e_shstrndx  = elf_half_to_cpu(ehdr.e_shstrndx);
 397
 398         shnum = ehdr.e_shnum;
 399         shstrndx = ehdr.e_shstrndx;
 400
 401         if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN))
 402                 die("Unsupported ELF header type\n");
 403         if (ehdr.e_machine != ELF_MACHINE)
 404                 die("Not for %s\n", ELF_MACHINE_NAME);
 405         if (ehdr.e_version != EV_CURRENT)
 406                 die("Unknown ELF version\n");
 407         if (ehdr.e_ehsize != sizeof(Elf_Ehdr))
 408                 die("Bad Elf header size\n");
 409         if (ehdr.e_phentsize != sizeof(Elf_Phdr))
 410                 die("Bad program header entry\n");
 411         if (ehdr.e_shentsize != sizeof(Elf_Shdr))
 412                 die("Bad section header entry\n");
 413
 414
 415         if (shnum == SHN_UNDEF || shstrndx == SHN_XINDEX) {
 416                 Elf_Shdr shdr;
 417
 418                 if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0)
 419                         die("Seek to %" FMT " failed: %s\n", ehdr.e_shoff, strerror(errno));
 420
 421                 if (fread(&shdr, sizeof(shdr), 1, fp) != 1)
 422                         die("Cannot read initial ELF section header: %s\n", strerror(errno));
 423
 424                 if (shnum == SHN_UNDEF)
 425                         shnum = elf_xword_to_cpu(shdr.sh_size);
 426
 427                 if (shstrndx == SHN_XINDEX)
 428                         shstrndx = elf_word_to_cpu(shdr.sh_link);
 429         }
 430
 431         if (shstrndx >= shnum)
 432                 die("String table index out of bounds\n");
 433 }
 434
 435 static void read_shdrs(FILE *fp)
 436 {
 437         int i;
 438         Elf_Shdr shdr;
 439
 440         secs = calloc(shnum, sizeof(struct section));
 441         if (!secs) {
 442                 die("Unable to allocate %ld section headers\n",
 443                     shnum);
 444         }
 445         if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
 446                 die("Seek to %" FMT " failed: %s\n",
 447                     ehdr.e_shoff, strerror(errno));
 448         }
 449         for (i = 0; i < shnum; i++) {
 450                 struct section *sec = &secs[i];
 451                 if (fread(&shdr, sizeof(shdr), 1, fp) != 1)
 452                         die("Cannot read ELF section headers %d/%ld: %s\n",
 453                             i, shnum, strerror(errno));
 454                 sec->shdr.sh_name      = elf_word_to_cpu(shdr.sh_name);
 455                 sec->shdr.sh_type      = elf_word_to_cpu(shdr.sh_type);
 456                 sec->shdr.sh_flags     = elf_xword_to_cpu(shdr.sh_flags);
 457                 sec->shdr.sh_addr      = elf_addr_to_cpu(shdr.sh_addr);
 458                 sec->shdr.sh_offset    = elf_off_to_cpu(shdr.sh_offset);
 459                 sec->shdr.sh_size      = elf_xword_to_cpu(shdr.sh_size);
 460                 sec->shdr.sh_link      = elf_word_to_cpu(shdr.sh_link);
 461                 sec->shdr.sh_info      = elf_word_to_cpu(shdr.sh_info);
 462                 sec->shdr.sh_addralign = elf_xword_to_cpu(shdr.sh_addralign);
 463                 sec->shdr.sh_entsize   = elf_xword_to_cpu(shdr.sh_entsize);
 464                 if (sec->shdr.sh_link < shnum)
 465                         sec->link = &secs[sec->shdr.sh_link];
 466         }
 467
 468 }
 469
 470 static void read_strtabs(FILE *fp)
 471 {
 472         int i;
 473         for (i = 0; i < shnum; i++) {
 474                 struct section *sec = &secs[i];
 475                 if (sec->shdr.sh_type != SHT_STRTAB) {
 476                         continue;
 477                 }
 478                 sec->strtab = malloc(sec->shdr.sh_size);
 479                 if (!sec->strtab) {
 480                         die("malloc of %" FMT " bytes for strtab failed\n",
 481                             sec->shdr.sh_size);
 482                 }
 483                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 484                         die("Seek to %" FMT " failed: %s\n",
 485                             sec->shdr.sh_offset, strerror(errno));
 486                 }
 487                 if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
 488                     != sec->shdr.sh_size) {
 489                         die("Cannot read symbol table: %s\n",
 490                                 strerror(errno));
 491                 }
 492         }
 493 }
 494
 495 static void read_symtabs(FILE *fp)
 496 {
 497         int i,j;
 498
 499         for (i = 0; i < shnum; i++) {
 500                 struct section *sec = &secs[i];
 501                 int num_syms;
 502
 503                 switch (sec->shdr.sh_type) {
 504                 case SHT_SYMTAB_SHNDX:
 505                         sec->xsymtab = malloc(sec->shdr.sh_size);
 506                         if (!sec->xsymtab) {
 507                                 die("malloc of %" FMT " bytes for xsymtab failed\n",
 508                                     sec->shdr.sh_size);
 509                         }
 510                         if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 511                                 die("Seek to %" FMT " failed: %s\n",
 512                                     sec->shdr.sh_offset, strerror(errno));
 513                         }
 514                         if (fread(sec->xsymtab, 1, sec->shdr.sh_size, fp)
 515                             != sec->shdr.sh_size) {
 516                                 die("Cannot read extended symbol table: %s\n",
 517                                     strerror(errno));
 518                         }
 519                         shxsymtabndx = i;
 520                         continue;
 521
 522                 case SHT_SYMTAB:
 523                         num_syms = sec->shdr.sh_size / sizeof(Elf_Sym);
 524
 525                         sec->symtab = malloc(sec->shdr.sh_size);
 526                         if (!sec->symtab) {
 527                                 die("malloc of %" FMT " bytes for symtab failed\n",
 528                                     sec->shdr.sh_size);
 529                         }
 530                         if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 531                                 die("Seek to %" FMT " failed: %s\n",
 532                                     sec->shdr.sh_offset, strerror(errno));
 533                         }
 534                         if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
 535                             != sec->shdr.sh_size) {
 536                                 die("Cannot read symbol table: %s\n",
 537                                     strerror(errno));
 538                         }
 539                         for (j = 0; j < num_syms; j++) {
 540                                 Elf_Sym *sym = &sec->symtab[j];
 541
 542                                 sym->st_name  = elf_word_to_cpu(sym->st_name);
 543                                 sym->st_value = elf_addr_to_cpu(sym->st_value);
 544                                 sym->st_size  = elf_xword_to_cpu(sym->st_size);
 545                                 sym->st_shndx = elf_half_to_cpu(sym->st_shndx);
 546                         }
 547                         shsymtabndx = i;
 548                         continue;
 549
 550                 default:
 551                         continue;
 552                 }
 553         }
 554 }
 555
 556
 557 static void read_relocs(FILE *fp)
 558 {
 559         int i,j;
 560         for (i = 0; i < shnum; i++) {
 561                 struct section *sec = &secs[i];
 562                 if (sec->shdr.sh_type != SHT_REL_TYPE) {
 563                         continue;
 564                 }
 565                 sec->reltab = malloc(sec->shdr.sh_size);
 566                 if (!sec->reltab) {
 567                         die("malloc of %" FMT " bytes for relocs failed\n",
 568                             sec->shdr.sh_size);
 569                 }
 570                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 571                         die("Seek to %" FMT " failed: %s\n",
 572                             sec->shdr.sh_offset, strerror(errno));
 573                 }
 574                 if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
 575                     != sec->shdr.sh_size) {
 576                         die("Cannot read symbol table: %s\n",
 577                                 strerror(errno));
 578                 }
 579                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
 580                         Elf_Rel *rel = &sec->reltab[j];
 581                         rel->r_offset = elf_addr_to_cpu(rel->r_offset);
 582                         rel->r_info   = elf_xword_to_cpu(rel->r_info);
 583 #if (SHT_REL_TYPE == SHT_RELA)
 584                         rel->r_addend = elf_xword_to_cpu(rel->r_addend);
 585 #endif
 586                 }
 587         }
 588 }
 589
 590
 591 static void print_absolute_symbols(void)
 592 {
 593         int i;
 594         const char *format;
 595
 596         if (ELF_BITS == 64)
 597                 format = "%5d %016"PRIx64" %5"PRId64" %10s %10s %12s %s\n";
 598         else
 599                 format = "%5d %08"PRIx32"  %5"PRId32" %10s %10s %12s %s\n";
 600
 601         printf("Absolute symbols\n");
 602         printf(" Num:    Value Size  Type       Bind        Visibility  Name\n");
 603         for (i = 0; i < shnum; i++) {
 604                 struct section *sec = &secs[i];
 605                 char *sym_strtab;
 606                 int j;
 607
 608                 if (sec->shdr.sh_type != SHT_SYMTAB) {
 609                         continue;
 610                 }
 611                 sym_strtab = sec->link->strtab;
 612                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Sym); j++) {
 613                         Elf_Sym *sym;
 614                         const char *name;
 615                         sym = &sec->symtab[j];
 616                         name = sym_name(sym_strtab, sym);
 617                         if (sym->st_shndx != SHN_ABS) {
 618                                 continue;
 619                         }
 620                         printf(format,
 621                                 j, sym->st_value, sym->st_size,
 622                                 sym_type(ELF_ST_TYPE(sym->st_info)),
 623                                 sym_bind(ELF_ST_BIND(sym->st_info)),
 624                                 sym_visibility(ELF_ST_VISIBILITY(sym->st_other)),
 625                                 name);
 626                 }
 627         }
 628         printf("\n");
 629 }
 630
 631 static void print_absolute_relocs(void)
 632 {
 633         int i, printed = 0;
 634         const char *format;
 635
 636         if (ELF_BITS == 64)
 637                 format = "%016"PRIx64" %016"PRIx64" %10s %016"PRIx64"  %s\n";
 638         else
 639                 format = "%08"PRIx32" %08"PRIx32" %10s %08"PRIx32"  %s\n";
 640
 641         for (i = 0; i < shnum; i++) {
 642                 struct section *sec = &secs[i];
 643                 struct section *sec_applies, *sec_symtab;
 644                 char *sym_strtab;
 645                 Elf_Sym *sh_symtab;
 646                 int j;
 647                 if (sec->shdr.sh_type != SHT_REL_TYPE) {
 648                         continue;
 649                 }
 650                 sec_symtab  = sec->link;
 651                 sec_applies = &secs[sec->shdr.sh_info];
 652                 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
 653                         continue;
 654                 }
 655                 sh_symtab  = sec_symtab->symtab;
 656                 sym_strtab = sec_symtab->link->strtab;
 657                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
 658                         Elf_Rel *rel;
 659                         Elf_Sym *sym;
 660                         const char *name;
 661                         rel = &sec->reltab[j];
 662                         sym = &sh_symtab[ELF_R_SYM(rel->r_info)];
 663                         name = sym_name(sym_strtab, sym);
 664                         if (sym->st_shndx != SHN_ABS) {
 665                                 continue;
 666                         }
 667
 668                         /* Absolute symbols are not relocated if bzImage is
 669                          * loaded at a non-compiled address. Display a warning
 670                          * to user at compile time about the absolute
 671                          * relocations present.
 672                          *
 673                          * User need to audit the code to make sure
 674                          * some symbols which should have been section
 675                          * relative have not become absolute because of some
 676                          * linker optimization or wrong programming usage.
 677                          *
 678                          * Before warning check if this absolute symbol
 679                          * relocation is harmless.
 680                          */
 681                         if (is_reloc(S_ABS, name) || is_reloc(S_REL, name))
 682                                 continue;
 683
 684                         if (!printed) {
 685                                 printf("WARNING: Absolute relocations"
 686                                         " present\n");
 687                                 printf("Offset     Info     Type     Sym.Value "
 688                                         "Sym.Name\n");
 689                                 printed = 1;
 690                         }
 691
 692                         printf(format,
 693                                 rel->r_offset,
 694                                 rel->r_info,
 695                                 rel_type(ELF_R_TYPE(rel->r_info)),
 696                                 sym->st_value,
 697                                 name);
 698                 }
 699         }
 700
 701         if (printed)
 702                 printf("\n");
 703 }
 704
 705 static void add_reloc(struct relocs *r, uint32_t offset)
 706 {
 707         if (r->count == r->size) {
 708                 unsigned long newsize = r->size + 50000;
 709                 void *mem = realloc(r->offset, newsize * sizeof(r->offset[0]));
 710
 711                 if (!mem)
 712                         die("realloc of %ld entries for relocs failed\n",
 713                                 newsize);
 714                 r->offset = mem;
 715                 r->size = newsize;
 716         }
 717         r->offset[r->count++] = offset;
 718 }
 719
 720 static void walk_relocs(int (*process)(struct section *sec, Elf_Rel *rel,
 721                         Elf_Sym *sym, const char *symname))
 722 {
 723         int i;
 724         /* Walk through the relocations */
 725         for (i = 0; i < shnum; i++) {
 726                 char *sym_strtab;
 727                 Elf_Sym *sh_symtab;
 728                 struct section *sec_applies, *sec_symtab;
 729                 int j;
 730                 struct section *sec = &secs[i];
 731
 732                 if (sec->shdr.sh_type != SHT_REL_TYPE) {
 733                         continue;
 734                 }
 735                 sec_symtab  = sec->link;
 736                 sec_applies = &secs[sec->shdr.sh_info];
 737                 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
 738                         continue;
 739                 }
 740                 sh_symtab = sec_symtab->symtab;
 741                 sym_strtab = sec_symtab->link->strtab;
 742                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
 743                         Elf_Rel *rel = &sec->reltab[j];
 744                         Elf_Sym *sym = &sh_symtab[ELF_R_SYM(rel->r_info)];
 745                         const char *symname = sym_name(sym_strtab, sym);
 746
 747                         process(sec, rel, sym, symname);
 748                 }
 749         }
 750 }
 751
 752 /*
 753  * The .data..percpu section is a special case for x86_64 SMP kernels.
 754  * It is used to initialize the actual per_cpu areas and to provide
 755  * definitions for the per_cpu variables that correspond to their offsets
 756  * within the percpu area. Since the values of all of the symbols need
 757  * to be offsets from the start of the per_cpu area the virtual address
 758  * (sh_addr) of .data..percpu is 0 in SMP kernels.
 759  *
 760  * This means that:
 761  *
 762  *      Relocations that reference symbols in the per_cpu area do not
 763  *      need further relocation (since the value is an offset relative
 764  *      to the start of the per_cpu area that does not change).
 765  *
 766  *      Relocations that apply to the per_cpu area need to have their
 767  *      offset adjusted by by the value of __per_cpu_load to make them
 768  *      point to the correct place in the loaded image (because the
 769  *      virtual address of .data..percpu is 0).
 770  *
 771  * For non SMP kernels .data..percpu is linked as part of the normal
 772  * kernel data and does not require special treatment.
 773  *
 774  */
 775 static int per_cpu_shndx        = -1;
 776 static Elf_Addr per_cpu_load_addr;
 777
 778 static void percpu_init(void)
 779 {
 780         int i;
 781         for (i = 0; i < shnum; i++) {
 782                 ElfW(Sym) *sym;
 783                 if (strcmp(sec_name(i), ".data..percpu"))
 784                         continue;
 785
 786                 if (secs[i].shdr.sh_addr != 0)  /* non SMP kernel */
 787                         return;
 788
 789                 sym = sym_lookup("__per_cpu_load");
 790                 if (!sym)
 791                         die("can't find __per_cpu_load\n");
 792
 793                 per_cpu_shndx = i;
 794                 per_cpu_load_addr = sym->st_value;
 795                 return;
 796         }
 797 }
 798
 799 #if ELF_BITS == 64
 800
 801 /*
 802  * Check to see if a symbol lies in the .data..percpu section.
 803  *
 804  * The linker incorrectly associates some symbols with the
 805  * .data..percpu section so we also need to check the symbol
 806  * name to make sure that we classify the symbol correctly.
 807  *
 808  * The GNU linker incorrectly associates:
 809  *      __init_begin
 810  *      __per_cpu_load
 811  *
 812  * The "gold" linker incorrectly associates:
 813  *      init_per_cpu__fixed_percpu_data
 814  *      init_per_cpu__gdt_page
 815  */
 816 static int is_percpu_sym(ElfW(Sym) *sym, const char *symname)
 817 {
 818         int shndx = sym_index(sym);
 819
 820         return (shndx == per_cpu_shndx) &&
 821                 strcmp(symname, "__init_begin") &&
 822                 strcmp(symname, "__per_cpu_load") &&
 823                 strncmp(symname, "init_per_cpu_", 13);
 824 }
 825
 826
 827 static int do_reloc64(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
 828                       const char *symname)
 829 {
 830         unsigned r_type = ELF64_R_TYPE(rel->r_info);
 831         ElfW(Addr) offset = rel->r_offset;
 832         int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
 833
 834         if (sym->st_shndx == SHN_UNDEF)
 835                 return 0;
 836
 837         /*
 838          * Adjust the offset if this reloc applies to the percpu section.
 839          */
 840         if (sec->shdr.sh_info == per_cpu_shndx)
 841                 offset += per_cpu_load_addr;
 842
 843         switch (r_type) {
 844         case R_X86_64_NONE:
 845                 /* NONE can be ignored. */
 846                 break;
 847
 848         case R_X86_64_PC32:
 849         case R_X86_64_PLT32:
 850                 /*
 851                  * PC relative relocations don't need to be adjusted unless
 852                  * referencing a percpu symbol.
 853                  *
 854                  * NB: R_X86_64_PLT32 can be treated as R_X86_64_PC32.
 855                  */
 856                 if (is_percpu_sym(sym, symname))
 857                         add_reloc(&relocs32neg, offset);
 858                 break;
 859
 860         case R_X86_64_PC64:
 861                 /*
 862                  * Only used by jump labels
 863                  */
 864                 if (is_percpu_sym(sym, symname))
 865                         die("Invalid R_X86_64_PC64 relocation against per-CPU symbol %s\n",
 866                             symname);
 867                 break;
 868
 869         case R_X86_64_32:
 870         case R_X86_64_32S:
 871         case R_X86_64_64:
 872                 /*
 873                  * References to the percpu area don't need to be adjusted.
 874                  */
 875                 if (is_percpu_sym(sym, symname))
 876                         break;
 877
 878                 if (shn_abs) {
 879                         /*
 880                          * Whitelisted absolute symbols do not require
 881                          * relocation.
 882                          */
 883                         if (is_reloc(S_ABS, symname))
 884                                 break;
 885
 886                         die("Invalid absolute %s relocation: %s\n",
 887                             rel_type(r_type), symname);
 888                         break;
 889                 }
 890
 891                 /*
 892                  * Relocation offsets for 64 bit kernels are output
 893                  * as 32 bits and sign extended back to 64 bits when
 894                  * the relocations are processed.
 895                  * Make sure that the offset will fit.
 896                  */
 897                 if ((int32_t)offset != (int64_t)offset)
 898                         die("Relocation offset doesn't fit in 32 bits\n");
 899
 900                 if (r_type == R_X86_64_64)
 901                         add_reloc(&relocs64, offset);
 902                 else
 903                         add_reloc(&relocs32, offset);
 904                 break;
 905
 906         default:
 907                 die("Unsupported relocation type: %s (%d)\n",
 908                     rel_type(r_type), r_type);
 909                 break;
 910         }
 911
 912         return 0;
 913 }
 914
 915 #else
 916
 917 static int do_reloc32(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
 918                       const char *symname)
 919 {
 920         unsigned r_type = ELF32_R_TYPE(rel->r_info);
 921         int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
 922
 923         switch (r_type) {
 924         case R_386_NONE:
 925         case R_386_PC32:
 926         case R_386_PC16:
 927         case R_386_PC8:
 928         case R_386_PLT32:
 929                 /*
 930                  * NONE can be ignored and PC relative relocations don't need
 931                  * to be adjusted. Because sym must be defined, R_386_PLT32 can
 932                  * be treated the same way as R_386_PC32.
 933                  */
 934                 break;
 935
 936         case R_386_32:
 937                 if (shn_abs) {
 938                         /*
 939                          * Whitelisted absolute symbols do not require
 940                          * relocation.
 941                          */
 942                         if (is_reloc(S_ABS, symname))
 943                                 break;
 944
 945                         die("Invalid absolute %s relocation: %s\n",
 946                             rel_type(r_type), symname);
 947                         break;
 948                 }
 949
 950                 add_reloc(&relocs32, rel->r_offset);
 951                 break;
 952
 953         default:
 954                 die("Unsupported relocation type: %s (%d)\n",
 955                     rel_type(r_type), r_type);
 956                 break;
 957         }
 958
 959         return 0;
 960 }
 961
 962 static int do_reloc_real(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
 963                          const char *symname)
 964 {
 965         unsigned r_type = ELF32_R_TYPE(rel->r_info);
 966         int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
 967
 968         switch (r_type) {
 969         case R_386_NONE:
 970         case R_386_PC32:
 971         case R_386_PC16:
 972         case R_386_PC8:
 973         case R_386_PLT32:
 974                 /*
 975                  * NONE can be ignored and PC relative relocations don't need
 976                  * to be adjusted. Because sym must be defined, R_386_PLT32 can
 977                  * be treated the same way as R_386_PC32.
 978                  */
 979                 break;
 980
 981         case R_386_16:
 982                 if (shn_abs) {
 983                         /*
 984                          * Whitelisted absolute symbols do not require
 985                          * relocation.
 986                          */
 987                         if (is_reloc(S_ABS, symname))
 988                                 break;
 989
 990                         if (is_reloc(S_SEG, symname)) {
 991                                 add_reloc(&relocs16, rel->r_offset);
 992                                 break;
 993                         }
 994                 } else {
 995                         if (!is_reloc(S_LIN, symname))
 996                                 break;
 997                 }
 998                 die("Invalid %s %s relocation: %s\n",
 999                     shn_abs ? "absolute" : "relative",
1000                     rel_type(r_type), symname);
1001                 break;
1002
1003         case R_386_32:
1004                 if (shn_abs) {
1005                         /*
1006                          * Whitelisted absolute symbols do not require
1007                          * relocation.
1008                          */
1009                         if (is_reloc(S_ABS, symname))
1010                                 break;
1011
1012                         if (is_reloc(S_REL, symname)) {
1013                                 add_reloc(&relocs32, rel->r_offset);
1014                                 break;
1015                         }
1016                 } else {
1017                         if (is_reloc(S_LIN, symname))
1018                                 add_reloc(&relocs32, rel->r_offset);
1019                         break;
1020                 }
1021                 die("Invalid %s %s relocation: %s\n",
1022                     shn_abs ? "absolute" : "relative",
1023                     rel_type(r_type), symname);
1024                 break;
1025
1026         default:
1027                 die("Unsupported relocation type: %s (%d)\n",
1028                     rel_type(r_type), r_type);
1029                 break;
1030         }
1031
1032         return 0;
1033 }
1034
1035 #endif
1036
1037 static int cmp_relocs(const void *va, const void *vb)
1038 {
1039         const uint32_t *a, *b;
1040         a = va; b = vb;
1041         return (*a == *b)? 0 : (*a > *b)? 1 : -1;
1042 }
1043
1044 static void sort_relocs(struct relocs *r)
1045 {
1046         qsort(r->offset, r->count, sizeof(r->offset[0]), cmp_relocs);
1047 }
1048
1049 static int write32(uint32_t v, FILE *f)
1050 {
1051         unsigned char buf[4];
1052
1053         put_unaligned_le32(v, buf);
1054         return fwrite(buf, 1, 4, f) == 4 ? 0 : -1;
1055 }
1056
1057 static int write32_as_text(uint32_t v, FILE *f)
1058 {
1059         return fprintf(f, "\t.long 0x%08"PRIx32"\n", v) > 0 ? 0 : -1;
1060 }
1061
1062 static void emit_relocs(int as_text, int use_real_mode)
1063 {
1064         int i;
1065         int (*write_reloc)(uint32_t, FILE *) = write32;
1066         int (*do_reloc)(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
1067                         const char *symname);
1068
1069 #if ELF_BITS == 64
1070         if (!use_real_mode)
1071                 do_reloc = do_reloc64;
1072         else
1073                 die("--realmode not valid for a 64-bit ELF file");
1074 #else
1075         if (!use_real_mode)
1076                 do_reloc = do_reloc32;
1077         else
1078                 do_reloc = do_reloc_real;
1079 #endif
1080
1081         /* Collect up the relocations */
1082         walk_relocs(do_reloc);
1083
1084         if (relocs16.count && !use_real_mode)
1085                 die("Segment relocations found but --realmode not specified\n");
1086
1087         /* Order the relocations for more efficient processing */
1088         sort_relocs(&relocs32);
1089 #if ELF_BITS == 64
1090         sort_relocs(&relocs32neg);
1091         sort_relocs(&relocs64);
1092 #else
1093         sort_relocs(&relocs16);
1094 #endif
1095
1096         /* Print the relocations */
1097         if (as_text) {
1098                 /* Print the relocations in a form suitable that
1099                  * gas will like.
1100                  */
1101                 printf(".section \".data.reloc\",\"a\"\n");
1102                 printf(".balign 4\n");
1103                 write_reloc = write32_as_text;
1104         }
1105
1106         if (use_real_mode) {
1107                 write_reloc(relocs16.count, stdout);
1108                 for (i = 0; i < relocs16.count; i++)
1109                         write_reloc(relocs16.offset[i], stdout);
1110
1111                 write_reloc(relocs32.count, stdout);
1112                 for (i = 0; i < relocs32.count; i++)
1113                         write_reloc(relocs32.offset[i], stdout);
1114         } else {
1115 #if ELF_BITS == 64
1116                 /* Print a stop */
1117                 write_reloc(0, stdout);
1118
1119                 /* Now print each relocation */
1120                 for (i = 0; i < relocs64.count; i++)
1121                         write_reloc(relocs64.offset[i], stdout);
1122
1123                 /* Print a stop */
1124                 write_reloc(0, stdout);
1125
1126                 /* Now print each inverse 32-bit relocation */
1127                 for (i = 0; i < relocs32neg.count; i++)
1128                         write_reloc(relocs32neg.offset[i], stdout);
1129 #endif
1130
1131                 /* Print a stop */
1132                 write_reloc(0, stdout);
1133
1134                 /* Now print each relocation */
1135                 for (i = 0; i < relocs32.count; i++)
1136                         write_reloc(relocs32.offset[i], stdout);
1137         }
1138 }
1139
1140 /*
1141  * As an aid to debugging problems with different linkers
1142  * print summary information about the relocs.
1143  * Since different linkers tend to emit the sections in
1144  * different orders we use the section names in the output.
1145  */
1146 static int do_reloc_info(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
1147                                 const char *symname)
1148 {
1149         printf("%s\t%s\t%s\t%s\n",
1150                 sec_name(sec->shdr.sh_info),
1151                 rel_type(ELF_R_TYPE(rel->r_info)),
1152                 symname,
1153                 sec_name(sym_index(sym)));
1154         return 0;
1155 }
1156
1157 static void print_reloc_info(void)
1158 {
1159         printf("reloc section\treloc type\tsymbol\tsymbol section\n");
1160         walk_relocs(do_reloc_info);
1161 }
1162
1163 #if ELF_BITS == 64
1164 # define process process_64
1165 #else
1166 # define process process_32
1167 #endif
1168
1169 void process(FILE *fp, int use_real_mode, int as_text,
1170              int show_absolute_syms, int show_absolute_relocs,
1171              int show_reloc_info)
1172 {
1173         regex_init(use_real_mode);
1174         read_ehdr(fp);
1175         read_shdrs(fp);
1176         read_strtabs(fp);
1177         read_symtabs(fp);
1178         read_relocs(fp);
1179         if (ELF_BITS == 64)
1180                 percpu_init();
1181         if (show_absolute_syms) {
1182                 print_absolute_symbols();
1183                 return;
1184         }
1185         if (show_absolute_relocs) {
1186                 print_absolute_relocs();
1187                 return;
1188         }
1189         if (show_reloc_info) {
1190                 print_reloc_info();
1191                 return;
1192         }
1193         emit_relocs(as_text, use_real_mode);
1194 }