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