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