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         "__kcfi_typeid_|"
  60         "__crc_)",
  61
  62 /*
  63  * These symbols are known to be relative, even if the linker marks them
  64  * as absolute (typically defined outside any section in the linker script.)
  65  */
  66         [S_REL] =
  67         "^(__init_(begin|end)|"
  68         "__x86_cpu_dev_(start|end)|"
  69         "(__parainstructions|__alt_instructions)(_end)?|"
  70         "(__iommu_table|__apicdrivers|__smp_locks)(_end)?|"
  71         "__(start|end)_pci_.*|"
  72 #if CONFIG_FW_LOADER
  73         "__(start|end)_builtin_fw|"
  74 #endif
  75         "__(start|stop)___ksymtab(_gpl)?|"
  76         "__(start|stop)___kcrctab(_gpl)?|"
  77         "__(start|stop)___param|"
  78         "__(start|stop)___modver|"
  79         "__(start|stop)___bug_table|"
  80         "__tracedata_(start|end)|"
  81         "__(start|stop)_notes|"
  82         "__end_rodata|"
  83         "__end_rodata_aligned|"
  84         "__initramfs_start|"
  85         "(jiffies|jiffies_64)|"
  86 #if ELF_BITS == 64
  87         "__per_cpu_load|"
  88         "init_per_cpu__.*|"
  89         "__end_rodata_hpage_align|"
  90 #endif
  91         "__vvar_page|"
  92         "_end)$"
  93 };
  94
  95
  96 static const char * const sym_regex_realmode[S_NSYMTYPES] = {
  97 /*
  98  * These symbols are known to be relative, even if the linker marks them
  99  * as absolute (typically defined outside any section in the linker script.)
 100  */
 101         [S_REL] =
 102         "^pa_",
 103
 104 /*
 105  * These are 16-bit segment symbols when compiling 16-bit code.
 106  */
 107         [S_SEG] =
 108         "^real_mode_seg$",
 109
 110 /*
 111  * These are offsets belonging to segments, as opposed to linear addresses,
 112  * when compiling 16-bit code.
 113  */
 114         [S_LIN] =
 115         "^pa_",
 116 };
 117
 118 static const char * const *sym_regex;
 119
 120 static regex_t sym_regex_c[S_NSYMTYPES];
 121 static int is_reloc(enum symtype type, const char *sym_name)
 122 {
 123         return sym_regex[type] &&
 124                 !regexec(&sym_regex_c[type], sym_name, 0, NULL, 0);
 125 }
 126
 127 static void regex_init(int use_real_mode)
 128 {
 129         char errbuf[128];
 130         int err;
 131         int i;
 132
 133         if (use_real_mode)
 134                 sym_regex = sym_regex_realmode;
 135         else
 136                 sym_regex = sym_regex_kernel;
 137
 138         for (i = 0; i < S_NSYMTYPES; i++) {
 139                 if (!sym_regex[i])
 140                         continue;
 141
 142                 err = regcomp(&sym_regex_c[i], sym_regex[i],
 143                               REG_EXTENDED|REG_NOSUB);
 144
 145                 if (err) {
 146                         regerror(err, &sym_regex_c[i], errbuf, sizeof(errbuf));
 147                         die("%s", errbuf);
 148                 }
 149         }
 150 }
 151
 152 static const char *sym_type(unsigned type)
 153 {
 154         static const char *type_name[] = {
 155 #define SYM_TYPE(X) [X] = #X
 156                 SYM_TYPE(STT_NOTYPE),
 157                 SYM_TYPE(STT_OBJECT),
 158                 SYM_TYPE(STT_FUNC),
 159                 SYM_TYPE(STT_SECTION),
 160                 SYM_TYPE(STT_FILE),
 161                 SYM_TYPE(STT_COMMON),
 162                 SYM_TYPE(STT_TLS),
 163 #undef SYM_TYPE
 164         };
 165         const char *name = "unknown sym type name";
 166         if (type < ARRAY_SIZE(type_name)) {
 167                 name = type_name[type];
 168         }
 169         return name;
 170 }
 171
 172 static const char *sym_bind(unsigned bind)
 173 {
 174         static const char *bind_name[] = {
 175 #define SYM_BIND(X) [X] = #X
 176                 SYM_BIND(STB_LOCAL),
 177                 SYM_BIND(STB_GLOBAL),
 178                 SYM_BIND(STB_WEAK),
 179 #undef SYM_BIND
 180         };
 181         const char *name = "unknown sym bind name";
 182         if (bind < ARRAY_SIZE(bind_name)) {
 183                 name = bind_name[bind];
 184         }
 185         return name;
 186 }
 187
 188 static const char *sym_visibility(unsigned visibility)
 189 {
 190         static const char *visibility_name[] = {
 191 #define SYM_VISIBILITY(X) [X] = #X
 192                 SYM_VISIBILITY(STV_DEFAULT),
 193                 SYM_VISIBILITY(STV_INTERNAL),
 194                 SYM_VISIBILITY(STV_HIDDEN),
 195                 SYM_VISIBILITY(STV_PROTECTED),
 196 #undef SYM_VISIBILITY
 197         };
 198         const char *name = "unknown sym visibility name";
 199         if (visibility < ARRAY_SIZE(visibility_name)) {
 200                 name = visibility_name[visibility];
 201         }
 202         return name;
 203 }
 204
 205 static const char *rel_type(unsigned type)
 206 {
 207         static const char *type_name[] = {
 208 #define REL_TYPE(X) [X] = #X
 209 #if ELF_BITS == 64
 210                 REL_TYPE(R_X86_64_NONE),
 211                 REL_TYPE(R_X86_64_64),
 212                 REL_TYPE(R_X86_64_PC64),
 213                 REL_TYPE(R_X86_64_PC32),
 214                 REL_TYPE(R_X86_64_GOT32),
 215                 REL_TYPE(R_X86_64_PLT32),
 216                 REL_TYPE(R_X86_64_COPY),
 217                 REL_TYPE(R_X86_64_GLOB_DAT),
 218                 REL_TYPE(R_X86_64_JUMP_SLOT),
 219                 REL_TYPE(R_X86_64_RELATIVE),
 220                 REL_TYPE(R_X86_64_GOTPCREL),
 221                 REL_TYPE(R_X86_64_32),
 222                 REL_TYPE(R_X86_64_32S),
 223                 REL_TYPE(R_X86_64_16),
 224                 REL_TYPE(R_X86_64_PC16),
 225                 REL_TYPE(R_X86_64_8),
 226                 REL_TYPE(R_X86_64_PC8),
 227 #else
 228                 REL_TYPE(R_386_NONE),
 229                 REL_TYPE(R_386_32),
 230                 REL_TYPE(R_386_PC32),
 231                 REL_TYPE(R_386_GOT32),
 232                 REL_TYPE(R_386_PLT32),
 233                 REL_TYPE(R_386_COPY),
 234                 REL_TYPE(R_386_GLOB_DAT),
 235                 REL_TYPE(R_386_JMP_SLOT),
 236                 REL_TYPE(R_386_RELATIVE),
 237                 REL_TYPE(R_386_GOTOFF),
 238                 REL_TYPE(R_386_GOTPC),
 239                 REL_TYPE(R_386_8),
 240                 REL_TYPE(R_386_PC8),
 241                 REL_TYPE(R_386_16),
 242                 REL_TYPE(R_386_PC16),
 243 #endif
 244 #undef REL_TYPE
 245         };
 246         const char *name = "unknown type rel type name";
 247         if (type < ARRAY_SIZE(type_name) && type_name[type]) {
 248                 name = type_name[type];
 249         }
 250         return name;
 251 }
 252
 253 static const char *sec_name(unsigned shndx)
 254 {
 255         const char *sec_strtab;
 256         const char *name;
 257         sec_strtab = secs[shstrndx].strtab;
 258         name = "<noname>";
 259         if (shndx < shnum) {
 260                 name = sec_strtab + secs[shndx].shdr.sh_name;
 261         }
 262         else if (shndx == SHN_ABS) {
 263                 name = "ABSOLUTE";
 264         }
 265         else if (shndx == SHN_COMMON) {
 266                 name = "COMMON";
 267         }
 268         return name;
 269 }
 270
 271 static const char *sym_name(const char *sym_strtab, Elf_Sym *sym)
 272 {
 273         const char *name;
 274         name = "<noname>";
 275         if (sym->st_name) {
 276                 name = sym_strtab + sym->st_name;
 277         }
 278         else {
 279                 name = sec_name(sym_index(sym));
 280         }
 281         return name;
 282 }
 283
 284 static Elf_Sym *sym_lookup(const char *symname)
 285 {
 286         int i;
 287         for (i = 0; i < shnum; i++) {
 288                 struct section *sec = &secs[i];
 289                 long nsyms;
 290                 char *strtab;
 291                 Elf_Sym *symtab;
 292                 Elf_Sym *sym;
 293
 294                 if (sec->shdr.sh_type != SHT_SYMTAB)
 295                         continue;
 296
 297                 nsyms = sec->shdr.sh_size/sizeof(Elf_Sym);
 298                 symtab = sec->symtab;
 299                 strtab = sec->link->strtab;
 300
 301                 for (sym = symtab; --nsyms >= 0; sym++) {
 302                         if (!sym->st_name)
 303                                 continue;
 304                         if (strcmp(symname, strtab + sym->st_name) == 0)
 305                                 return sym;
 306                 }
 307         }
 308         return 0;
 309 }
 310
 311 #if BYTE_ORDER == LITTLE_ENDIAN
 312 #define le16_to_cpu(val) (val)
 313 #define le32_to_cpu(val) (val)
 314 #define le64_to_cpu(val) (val)
 315 #endif
 316 #if BYTE_ORDER == BIG_ENDIAN
 317 #define le16_to_cpu(val) bswap_16(val)
 318 #define le32_to_cpu(val) bswap_32(val)
 319 #define le64_to_cpu(val) bswap_64(val)
 320 #endif
 321
 322 static uint16_t elf16_to_cpu(uint16_t val)
 323 {
 324         return le16_to_cpu(val);
 325 }
 326
 327 static uint32_t elf32_to_cpu(uint32_t val)
 328 {
 329         return le32_to_cpu(val);
 330 }
 331
 332 #define elf_half_to_cpu(x)      elf16_to_cpu(x)
 333 #define elf_word_to_cpu(x)      elf32_to_cpu(x)
 334
 335 #if ELF_BITS == 64
 336 static uint64_t elf64_to_cpu(uint64_t val)
 337 {
 338         return le64_to_cpu(val);
 339 }
 340 #define elf_addr_to_cpu(x)      elf64_to_cpu(x)
 341 #define elf_off_to_cpu(x)       elf64_to_cpu(x)
 342 #define elf_xword_to_cpu(x)     elf64_to_cpu(x)
 343 #else
 344 #define elf_addr_to_cpu(x)      elf32_to_cpu(x)
 345 #define elf_off_to_cpu(x)       elf32_to_cpu(x)
 346 #define elf_xword_to_cpu(x)     elf32_to_cpu(x)
 347 #endif
 348
 349 static int sym_index(Elf_Sym *sym)
 350 {
 351         Elf_Sym *symtab = secs[shsymtabndx].symtab;
 352         Elf32_Word *xsymtab = secs[shxsymtabndx].xsymtab;
 353         unsigned long offset;
 354         int index;
 355
 356         if (sym->st_shndx != SHN_XINDEX)
 357                 return sym->st_shndx;
 358
 359         /* calculate offset of sym from head of table. */
 360         offset = (unsigned long)sym - (unsigned long)symtab;
 361         index = offset / sizeof(*sym);
 362
 363         return elf32_to_cpu(xsymtab[index]);
 364 }
 365
 366 static void read_ehdr(FILE *fp)
 367 {
 368         if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
 369                 die("Cannot read ELF header: %s\n",
 370                         strerror(errno));
 371         }
 372         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) {
 373                 die("No ELF magic\n");
 374         }
 375         if (ehdr.e_ident[EI_CLASS] != ELF_CLASS) {
 376                 die("Not a %d bit executable\n", ELF_BITS);
 377         }
 378         if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
 379                 die("Not a LSB ELF executable\n");
 380         }
 381         if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
 382                 die("Unknown ELF version\n");
 383         }
 384         /* Convert the fields to native endian */
 385         ehdr.e_type      = elf_half_to_cpu(ehdr.e_type);
 386         ehdr.e_machine   = elf_half_to_cpu(ehdr.e_machine);
 387         ehdr.e_version   = elf_word_to_cpu(ehdr.e_version);
 388         ehdr.e_entry     = elf_addr_to_cpu(ehdr.e_entry);
 389         ehdr.e_phoff     = elf_off_to_cpu(ehdr.e_phoff);
 390         ehdr.e_shoff     = elf_off_to_cpu(ehdr.e_shoff);
 391         ehdr.e_flags     = elf_word_to_cpu(ehdr.e_flags);
 392         ehdr.e_ehsize    = elf_half_to_cpu(ehdr.e_ehsize);
 393         ehdr.e_phentsize = elf_half_to_cpu(ehdr.e_phentsize);
 394         ehdr.e_phnum     = elf_half_to_cpu(ehdr.e_phnum);
 395         ehdr.e_shentsize = elf_half_to_cpu(ehdr.e_shentsize);
 396         ehdr.e_shnum     = elf_half_to_cpu(ehdr.e_shnum);
 397         ehdr.e_shstrndx  = elf_half_to_cpu(ehdr.e_shstrndx);
 398
 399         shnum = ehdr.e_shnum;
 400         shstrndx = ehdr.e_shstrndx;
 401
 402         if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN))
 403                 die("Unsupported ELF header type\n");
 404         if (ehdr.e_machine != ELF_MACHINE)
 405                 die("Not for %s\n", ELF_MACHINE_NAME);
 406         if (ehdr.e_version != EV_CURRENT)
 407                 die("Unknown ELF version\n");
 408         if (ehdr.e_ehsize != sizeof(Elf_Ehdr))
 409                 die("Bad ELF header size\n");
 410         if (ehdr.e_phentsize != sizeof(Elf_Phdr))
 411                 die("Bad program header entry\n");
 412         if (ehdr.e_shentsize != sizeof(Elf_Shdr))
 413                 die("Bad section header entry\n");
 414
 415
 416         if (shnum == SHN_UNDEF || shstrndx == SHN_XINDEX) {
 417                 Elf_Shdr shdr;
 418
 419                 if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0)
 420                         die("Seek to %" FMT " failed: %s\n", ehdr.e_shoff, strerror(errno));
 421
 422                 if (fread(&shdr, sizeof(shdr), 1, fp) != 1)
 423                         die("Cannot read initial ELF section header: %s\n", strerror(errno));
 424
 425                 if (shnum == SHN_UNDEF)
 426                         shnum = elf_xword_to_cpu(shdr.sh_size);
 427
 428                 if (shstrndx == SHN_XINDEX)
 429                         shstrndx = elf_word_to_cpu(shdr.sh_link);
 430         }
 431
 432         if (shstrndx >= shnum)
 433                 die("String table index out of bounds\n");
 434 }
 435
 436 static void read_shdrs(FILE *fp)
 437 {
 438         int i;
 439         Elf_Shdr shdr;
 440
 441         secs = calloc(shnum, sizeof(struct section));
 442         if (!secs) {
 443                 die("Unable to allocate %ld section headers\n",
 444                     shnum);
 445         }
 446         if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
 447                 die("Seek to %" FMT " failed: %s\n",
 448                     ehdr.e_shoff, strerror(errno));
 449         }
 450         for (i = 0; i < shnum; i++) {
 451                 struct section *sec = &secs[i];
 452                 if (fread(&shdr, sizeof(shdr), 1, fp) != 1)
 453                         die("Cannot read ELF section headers %d/%ld: %s\n",
 454                             i, shnum, strerror(errno));
 455                 sec->shdr.sh_name      = elf_word_to_cpu(shdr.sh_name);
 456                 sec->shdr.sh_type      = elf_word_to_cpu(shdr.sh_type);
 457                 sec->shdr.sh_flags     = elf_xword_to_cpu(shdr.sh_flags);
 458                 sec->shdr.sh_addr      = elf_addr_to_cpu(shdr.sh_addr);
 459                 sec->shdr.sh_offset    = elf_off_to_cpu(shdr.sh_offset);
 460                 sec->shdr.sh_size      = elf_xword_to_cpu(shdr.sh_size);
 461                 sec->shdr.sh_link      = elf_word_to_cpu(shdr.sh_link);
 462                 sec->shdr.sh_info      = elf_word_to_cpu(shdr.sh_info);
 463                 sec->shdr.sh_addralign = elf_xword_to_cpu(shdr.sh_addralign);
 464                 sec->shdr.sh_entsize   = elf_xword_to_cpu(shdr.sh_entsize);
 465                 if (sec->shdr.sh_link < shnum)
 466                         sec->link = &secs[sec->shdr.sh_link];
 467         }
 468
 469 }
 470
 471 static void read_strtabs(FILE *fp)
 472 {
 473         int i;
 474         for (i = 0; i < shnum; i++) {
 475                 struct section *sec = &secs[i];
 476                 if (sec->shdr.sh_type != SHT_STRTAB) {
 477                         continue;
 478                 }
 479                 sec->strtab = malloc(sec->shdr.sh_size);
 480                 if (!sec->strtab) {
 481                         die("malloc of %" FMT " bytes for strtab 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->strtab, 1, sec->shdr.sh_size, fp)
 489                     != sec->shdr.sh_size) {
 490                         die("Cannot read symbol table: %s\n",
 491                                 strerror(errno));
 492                 }
 493         }
 494 }
 495
 496 static void read_symtabs(FILE *fp)
 497 {
 498         int i,j;
 499
 500         for (i = 0; i < shnum; i++) {
 501                 struct section *sec = &secs[i];
 502                 int num_syms;
 503
 504                 switch (sec->shdr.sh_type) {
 505                 case SHT_SYMTAB_SHNDX:
 506                         sec->xsymtab = malloc(sec->shdr.sh_size);
 507                         if (!sec->xsymtab) {
 508                                 die("malloc of %" FMT " bytes for xsymtab failed\n",
 509                                     sec->shdr.sh_size);
 510                         }
 511                         if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 512                                 die("Seek to %" FMT " failed: %s\n",
 513                                     sec->shdr.sh_offset, strerror(errno));
 514                         }
 515                         if (fread(sec->xsymtab, 1, sec->shdr.sh_size, fp)
 516                             != sec->shdr.sh_size) {
 517                                 die("Cannot read extended symbol table: %s\n",
 518                                     strerror(errno));
 519                         }
 520                         shxsymtabndx = i;
 521                         continue;
 522
 523                 case SHT_SYMTAB:
 524                         num_syms = sec->shdr.sh_size / sizeof(Elf_Sym);
 525
 526                         sec->symtab = malloc(sec->shdr.sh_size);
 527                         if (!sec->symtab) {
 528                                 die("malloc of %" FMT " bytes for symtab failed\n",
 529                                     sec->shdr.sh_size);
 530                         }
 531                         if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 532                                 die("Seek to %" FMT " failed: %s\n",
 533                                     sec->shdr.sh_offset, strerror(errno));
 534                         }
 535                         if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
 536                             != sec->shdr.sh_size) {
 537                                 die("Cannot read symbol table: %s\n",
 538                                     strerror(errno));
 539                         }
 540                         for (j = 0; j < num_syms; j++) {
 541                                 Elf_Sym *sym = &sec->symtab[j];
 542
 543                                 sym->st_name  = elf_word_to_cpu(sym->st_name);
 544                                 sym->st_value = elf_addr_to_cpu(sym->st_value);
 545                                 sym->st_size  = elf_xword_to_cpu(sym->st_size);
 546                                 sym->st_shndx = elf_half_to_cpu(sym->st_shndx);
 547                         }
 548                         shsymtabndx = i;
 549                         continue;
 550
 551                 default:
 552                         continue;
 553                 }
 554         }
 555 }
 556
 557
 558 static void read_relocs(FILE *fp)
 559 {
 560         int i,j;
 561         for (i = 0; i < shnum; i++) {
 562                 struct section *sec = &secs[i];
 563                 if (sec->shdr.sh_type != SHT_REL_TYPE) {
 564                         continue;
 565                 }
 566                 sec->reltab = malloc(sec->shdr.sh_size);
 567                 if (!sec->reltab) {
 568                         die("malloc of %" FMT " bytes for relocs failed\n",
 569                             sec->shdr.sh_size);
 570                 }
 571                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 572                         die("Seek to %" FMT " failed: %s\n",
 573                             sec->shdr.sh_offset, strerror(errno));
 574                 }
 575                 if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
 576                     != sec->shdr.sh_size) {
 577                         die("Cannot read symbol table: %s\n",
 578                                 strerror(errno));
 579                 }
 580                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
 581                         Elf_Rel *rel = &sec->reltab[j];
 582                         rel->r_offset = elf_addr_to_cpu(rel->r_offset);
 583                         rel->r_info   = elf_xword_to_cpu(rel->r_info);
 584 #if (SHT_REL_TYPE == SHT_RELA)
 585                         rel->r_addend = elf_xword_to_cpu(rel->r_addend);
 586 #endif
 587                 }
 588         }
 589 }
 590
 591
 592 static void print_absolute_symbols(void)
 593 {
 594         int i;
 595         const char *format;
 596
 597         if (ELF_BITS == 64)
 598                 format = "%5d %016"PRIx64" %5"PRId64" %10s %10s %12s %s\n";
 599         else
 600                 format = "%5d %08"PRIx32"  %5"PRId32" %10s %10s %12s %s\n";
 601
 602         printf("Absolute symbols\n");
 603         printf(" Num:    Value Size  Type       Bind        Visibility  Name\n");
 604         for (i = 0; i < shnum; i++) {
 605                 struct section *sec = &secs[i];
 606                 char *sym_strtab;
 607                 int j;
 608
 609                 if (sec->shdr.sh_type != SHT_SYMTAB) {
 610                         continue;
 611                 }
 612                 sym_strtab = sec->link->strtab;
 613                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Sym); j++) {
 614                         Elf_Sym *sym;
 615                         const char *name;
 616                         sym = &sec->symtab[j];
 617                         name = sym_name(sym_strtab, sym);
 618                         if (sym->st_shndx != SHN_ABS) {
 619                                 continue;
 620                         }
 621                         printf(format,
 622                                 j, sym->st_value, sym->st_size,
 623                                 sym_type(ELF_ST_TYPE(sym->st_info)),
 624                                 sym_bind(ELF_ST_BIND(sym->st_info)),
 625                                 sym_visibility(ELF_ST_VISIBILITY(sym->st_other)),
 626                                 name);
 627                 }
 628         }
 629         printf("\n");
 630 }
 631
 632 static void print_absolute_relocs(void)
 633 {
 634         int i, printed = 0;
 635         const char *format;
 636
 637         if (ELF_BITS == 64)
 638                 format = "%016"PRIx64" %016"PRIx64" %10s %016"PRIx64"  %s\n";
 639         else
 640                 format = "%08"PRIx32" %08"PRIx32" %10s %08"PRIx32"  %s\n";
 641
 642         for (i = 0; i < shnum; i++) {
 643                 struct section *sec = &secs[i];
 644                 struct section *sec_applies, *sec_symtab;
 645                 char *sym_strtab;
 646                 Elf_Sym *sh_symtab;
 647                 int j;
 648                 if (sec->shdr.sh_type != SHT_REL_TYPE) {
 649                         continue;
 650                 }
 651                 sec_symtab  = sec->link;
 652                 sec_applies = &secs[sec->shdr.sh_info];
 653                 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
 654                         continue;
 655                 }
 656                 sh_symtab  = sec_symtab->symtab;
 657                 sym_strtab = sec_symtab->link->strtab;
 658                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
 659                         Elf_Rel *rel;
 660                         Elf_Sym *sym;
 661                         const char *name;
 662                         rel = &sec->reltab[j];
 663                         sym = &sh_symtab[ELF_R_SYM(rel->r_info)];
 664                         name = sym_name(sym_strtab, sym);
 665                         if (sym->st_shndx != SHN_ABS) {
 666                                 continue;
 667                         }
 668
 669                         /* Absolute symbols are not relocated if bzImage is
 670                          * loaded at a non-compiled address. Display a warning
 671                          * to user at compile time about the absolute
 672                          * relocations present.
 673                          *
 674                          * User need to audit the code to make sure
 675                          * some symbols which should have been section
 676                          * relative have not become absolute because of some
 677                          * linker optimization or wrong programming usage.
 678                          *
 679                          * Before warning check if this absolute symbol
 680                          * relocation is harmless.
 681                          */
 682                         if (is_reloc(S_ABS, name) || is_reloc(S_REL, name))
 683                                 continue;
 684
 685                         if (!printed) {
 686                                 printf("WARNING: Absolute relocations"
 687                                         " present\n");
 688                                 printf("Offset     Info     Type     Sym.Value "
 689                                         "Sym.Name\n");
 690                                 printed = 1;
 691                         }
 692
 693                         printf(format,
 694                                 rel->r_offset,
 695                                 rel->r_info,
 696                                 rel_type(ELF_R_TYPE(rel->r_info)),
 697                                 sym->st_value,
 698                                 name);
 699                 }
 700         }
 701
 702         if (printed)
 703                 printf("\n");
 704 }
 705
 706 static void add_reloc(struct relocs *r, uint32_t offset)
 707 {
 708         if (r->count == r->size) {
 709                 unsigned long newsize = r->size + 50000;
 710                 void *mem = realloc(r->offset, newsize * sizeof(r->offset[0]));
 711
 712                 if (!mem)
 713                         die("realloc of %ld entries for relocs failed\n",
 714                                 newsize);
 715                 r->offset = mem;
 716                 r->size = newsize;
 717         }
 718         r->offset[r->count++] = offset;
 719 }
 720
 721 static void walk_relocs(int (*process)(struct section *sec, Elf_Rel *rel,
 722                         Elf_Sym *sym, const char *symname))
 723 {
 724         int i;
 725         /* Walk through the relocations */
 726         for (i = 0; i < shnum; i++) {
 727                 char *sym_strtab;
 728                 Elf_Sym *sh_symtab;
 729                 struct section *sec_applies, *sec_symtab;
 730                 int j;
 731                 struct section *sec = &secs[i];
 732
 733                 if (sec->shdr.sh_type != SHT_REL_TYPE) {
 734                         continue;
 735                 }
 736                 sec_symtab  = sec->link;
 737                 sec_applies = &secs[sec->shdr.sh_info];
 738                 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
 739                         continue;
 740                 }
 741                 sh_symtab = sec_symtab->symtab;
 742                 sym_strtab = sec_symtab->link->strtab;
 743                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
 744                         Elf_Rel *rel = &sec->reltab[j];
 745                         Elf_Sym *sym = &sh_symtab[ELF_R_SYM(rel->r_info)];
 746                         const char *symname = sym_name(sym_strtab, sym);
 747
 748                         process(sec, rel, sym, symname);
 749                 }
 750         }
 751 }
 752
 753 /*
 754  * The .data..percpu section is a special case for x86_64 SMP kernels.
 755  * It is used to initialize the actual per_cpu areas and to provide
 756  * definitions for the per_cpu variables that correspond to their offsets
 757  * within the percpu area. Since the values of all of the symbols need
 758  * to be offsets from the start of the per_cpu area the virtual address
 759  * (sh_addr) of .data..percpu is 0 in SMP kernels.
 760  *
 761  * This means that:
 762  *
 763  *      Relocations that reference symbols in the per_cpu area do not
 764  *      need further relocation (since the value is an offset relative
 765  *      to the start of the per_cpu area that does not change).
 766  *
 767  *      Relocations that apply to the per_cpu area need to have their
 768  *      offset adjusted by by the value of __per_cpu_load to make them
 769  *      point to the correct place in the loaded image (because the
 770  *      virtual address of .data..percpu is 0).
 771  *
 772  * For non SMP kernels .data..percpu is linked as part of the normal
 773  * kernel data and does not require special treatment.
 774  *
 775  */
 776 static int per_cpu_shndx        = -1;
 777 static Elf_Addr per_cpu_load_addr;
 778
 779 static void percpu_init(void)
 780 {
 781         int i;
 782         for (i = 0; i < shnum; i++) {
 783                 ElfW(Sym) *sym;
 784                 if (strcmp(sec_name(i), ".data..percpu"))
 785                         continue;
 786
 787                 if (secs[i].shdr.sh_addr != 0)  /* non SMP kernel */
 788                         return;
 789
 790                 sym = sym_lookup("__per_cpu_load");
 791                 if (!sym)
 792                         die("can't find __per_cpu_load\n");
 793
 794                 per_cpu_shndx = i;
 795                 per_cpu_load_addr = sym->st_value;
 796                 return;
 797         }
 798 }
 799
 800 #if ELF_BITS == 64
 801
 802 /*
 803  * Check to see if a symbol lies in the .data..percpu section.
 804  *
 805  * The linker incorrectly associates some symbols with the
 806  * .data..percpu section so we also need to check the symbol
 807  * name to make sure that we classify the symbol correctly.
 808  *
 809  * The GNU linker incorrectly associates:
 810  *      __init_begin
 811  *      __per_cpu_load
 812  *
 813  * The "gold" linker incorrectly associates:
 814  *      init_per_cpu__fixed_percpu_data
 815  *      init_per_cpu__gdt_page
 816  */
 817 static int is_percpu_sym(ElfW(Sym) *sym, const char *symname)
 818 {
 819         int shndx = sym_index(sym);
 820
 821         return (shndx == per_cpu_shndx) &&
 822                 strcmp(symname, "__init_begin") &&
 823                 strcmp(symname, "__per_cpu_load") &&
 824                 strncmp(symname, "init_per_cpu_", 13);
 825 }
 826
 827
 828 static int do_reloc64(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
 829                       const char *symname)
 830 {
 831         unsigned r_type = ELF64_R_TYPE(rel->r_info);
 832         ElfW(Addr) offset = rel->r_offset;
 833         int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
 834
 835         if (sym->st_shndx == SHN_UNDEF)
 836                 return 0;
 837
 838         /*
 839          * Adjust the offset if this reloc applies to the percpu section.
 840          */
 841         if (sec->shdr.sh_info == per_cpu_shndx)
 842                 offset += per_cpu_load_addr;
 843
 844         switch (r_type) {
 845         case R_X86_64_NONE:
 846                 /* NONE can be ignored. */
 847                 break;
 848
 849         case R_X86_64_PC32:
 850         case R_X86_64_PLT32:
 851                 /*
 852                  * PC relative relocations don't need to be adjusted unless
 853                  * referencing a percpu symbol.
 854                  *
 855                  * NB: R_X86_64_PLT32 can be treated as R_X86_64_PC32.
 856                  */
 857                 if (is_percpu_sym(sym, symname))
 858                         add_reloc(&relocs32neg, offset);
 859                 break;
 860
 861         case R_X86_64_PC64:
 862                 /*
 863                  * Only used by jump labels
 864                  */
 865                 if (is_percpu_sym(sym, symname))
 866                         die("Invalid R_X86_64_PC64 relocation against per-CPU symbol %s\n",
 867                             symname);
 868                 break;
 869
 870         case R_X86_64_32:
 871         case R_X86_64_32S:
 872         case R_X86_64_64:
 873                 /*
 874                  * References to the percpu area don't need to be adjusted.
 875                  */
 876                 if (is_percpu_sym(sym, symname))
 877                         break;
 878
 879                 if (shn_abs) {
 880                         /*
 881                          * Whitelisted absolute symbols do not require
 882                          * relocation.
 883                          */
 884                         if (is_reloc(S_ABS, symname))
 885                                 break;
 886
 887                         die("Invalid absolute %s relocation: %s\n",
 888                             rel_type(r_type), symname);
 889                         break;
 890                 }
 891
 892                 /*
 893                  * Relocation offsets for 64 bit kernels are output
 894                  * as 32 bits and sign extended back to 64 bits when
 895                  * the relocations are processed.
 896                  * Make sure that the offset will fit.
 897                  */
 898                 if ((int32_t)offset != (int64_t)offset)
 899                         die("Relocation offset doesn't fit in 32 bits\n");
 900
 901                 if (r_type == R_X86_64_64)
 902                         add_reloc(&relocs64, offset);
 903                 else
 904                         add_reloc(&relocs32, offset);
 905                 break;
 906
 907         default:
 908                 die("Unsupported relocation type: %s (%d)\n",
 909                     rel_type(r_type), r_type);
 910                 break;
 911         }
 912
 913         return 0;
 914 }
 915
 916 #else
 917
 918 static int do_reloc32(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
 919                       const char *symname)
 920 {
 921         unsigned r_type = ELF32_R_TYPE(rel->r_info);
 922         int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
 923
 924         switch (r_type) {
 925         case R_386_NONE:
 926         case R_386_PC32:
 927         case R_386_PC16:
 928         case R_386_PC8:
 929         case R_386_PLT32:
 930                 /*
 931                  * NONE can be ignored and PC relative relocations don't need
 932                  * to be adjusted. Because sym must be defined, R_386_PLT32 can
 933                  * be treated the same way as R_386_PC32.
 934                  */
 935                 break;
 936
 937         case R_386_32:
 938                 if (shn_abs) {
 939                         /*
 940                          * Whitelisted absolute symbols do not require
 941                          * relocation.
 942                          */
 943                         if (is_reloc(S_ABS, symname))
 944                                 break;
 945
 946                         die("Invalid absolute %s relocation: %s\n",
 947                             rel_type(r_type), symname);
 948                         break;
 949                 }
 950
 951                 add_reloc(&relocs32, rel->r_offset);
 952                 break;
 953
 954         default:
 955                 die("Unsupported relocation type: %s (%d)\n",
 956                     rel_type(r_type), r_type);
 957                 break;
 958         }
 959
 960         return 0;
 961 }
 962
 963 static int do_reloc_real(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
 964                          const char *symname)
 965 {
 966         unsigned r_type = ELF32_R_TYPE(rel->r_info);
 967         int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
 968
 969         switch (r_type) {
 970         case R_386_NONE:
 971         case R_386_PC32:
 972         case R_386_PC16:
 973         case R_386_PC8:
 974         case R_386_PLT32:
 975                 /*
 976                  * NONE can be ignored and PC relative relocations don't need
 977                  * to be adjusted. Because sym must be defined, R_386_PLT32 can
 978                  * be treated the same way as R_386_PC32.
 979                  */
 980                 break;
 981
 982         case R_386_16:
 983                 if (shn_abs) {
 984                         /*
 985                          * Whitelisted absolute symbols do not require
 986                          * relocation.
 987                          */
 988                         if (is_reloc(S_ABS, symname))
 989                                 break;
 990
 991                         if (is_reloc(S_SEG, symname)) {
 992                                 add_reloc(&relocs16, rel->r_offset);
 993                                 break;
 994                         }
 995                 } else {
 996                         if (!is_reloc(S_LIN, symname))
 997                                 break;
 998                 }
 999                 die("Invalid %s %s relocation: %s\n",
1000                     shn_abs ? "absolute" : "relative",
1001                     rel_type(r_type), symname);
1002                 break;
1003
1004         case R_386_32:
1005                 if (shn_abs) {
1006                         /*
1007                          * Whitelisted absolute symbols do not require
1008                          * relocation.
1009                          */
1010                         if (is_reloc(S_ABS, symname))
1011                                 break;
1012
1013                         if (is_reloc(S_REL, symname)) {
1014                                 add_reloc(&relocs32, rel->r_offset);
1015                                 break;
1016                         }
1017                 } else {
1018                         if (is_reloc(S_LIN, symname))
1019                                 add_reloc(&relocs32, rel->r_offset);
1020                         break;
1021                 }
1022                 die("Invalid %s %s relocation: %s\n",
1023                     shn_abs ? "absolute" : "relative",
1024                     rel_type(r_type), symname);
1025                 break;
1026
1027         default:
1028                 die("Unsupported relocation type: %s (%d)\n",
1029                     rel_type(r_type), r_type);
1030                 break;
1031         }
1032
1033         return 0;
1034 }
1035
1036 #endif
1037
1038 static int cmp_relocs(const void *va, const void *vb)
1039 {
1040         const uint32_t *a, *b;
1041         a = va; b = vb;
1042         return (*a == *b)? 0 : (*a > *b)? 1 : -1;
1043 }
1044
1045 static void sort_relocs(struct relocs *r)
1046 {
1047         qsort(r->offset, r->count, sizeof(r->offset[0]), cmp_relocs);
1048 }
1049
1050 static int write32(uint32_t v, FILE *f)
1051 {
1052         unsigned char buf[4];
1053
1054         put_unaligned_le32(v, buf);
1055         return fwrite(buf, 1, 4, f) == 4 ? 0 : -1;
1056 }
1057
1058 static int write32_as_text(uint32_t v, FILE *f)
1059 {
1060         return fprintf(f, "\t.long 0x%08"PRIx32"\n", v) > 0 ? 0 : -1;
1061 }
1062
1063 static void emit_relocs(int as_text, int use_real_mode)
1064 {
1065         int i;
1066         int (*write_reloc)(uint32_t, FILE *) = write32;
1067         int (*do_reloc)(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
1068                         const char *symname);
1069
1070 #if ELF_BITS == 64
1071         if (!use_real_mode)
1072                 do_reloc = do_reloc64;
1073         else
1074                 die("--realmode not valid for a 64-bit ELF file");
1075 #else
1076         if (!use_real_mode)
1077                 do_reloc = do_reloc32;
1078         else
1079                 do_reloc = do_reloc_real;
1080 #endif
1081
1082         /* Collect up the relocations */
1083         walk_relocs(do_reloc);
1084
1085         if (relocs16.count && !use_real_mode)
1086                 die("Segment relocations found but --realmode not specified\n");
1087
1088         /* Order the relocations for more efficient processing */
1089         sort_relocs(&relocs32);
1090 #if ELF_BITS == 64
1091         sort_relocs(&relocs32neg);
1092         sort_relocs(&relocs64);
1093 #else
1094         sort_relocs(&relocs16);
1095 #endif
1096
1097         /* Print the relocations */
1098         if (as_text) {
1099                 /* Print the relocations in a form suitable that
1100                  * gas will like.
1101                  */
1102                 printf(".section \".data.reloc\",\"a\"\n");
1103                 printf(".balign 4\n");
1104                 write_reloc = write32_as_text;
1105         }
1106
1107         if (use_real_mode) {
1108                 write_reloc(relocs16.count, stdout);
1109                 for (i = 0; i < relocs16.count; i++)
1110                         write_reloc(relocs16.offset[i], stdout);
1111
1112                 write_reloc(relocs32.count, stdout);
1113                 for (i = 0; i < relocs32.count; i++)
1114                         write_reloc(relocs32.offset[i], stdout);
1115         } else {
1116 #if ELF_BITS == 64
1117                 /* Print a stop */
1118                 write_reloc(0, stdout);
1119
1120                 /* Now print each relocation */
1121                 for (i = 0; i < relocs64.count; i++)
1122                         write_reloc(relocs64.offset[i], stdout);
1123
1124                 /* Print a stop */
1125                 write_reloc(0, stdout);
1126
1127                 /* Now print each inverse 32-bit relocation */
1128                 for (i = 0; i < relocs32neg.count; i++)
1129                         write_reloc(relocs32neg.offset[i], stdout);
1130 #endif
1131
1132                 /* Print a stop */
1133                 write_reloc(0, stdout);
1134
1135                 /* Now print each relocation */
1136                 for (i = 0; i < relocs32.count; i++)
1137                         write_reloc(relocs32.offset[i], stdout);
1138         }
1139 }
1140
1141 /*
1142  * As an aid to debugging problems with different linkers
1143  * print summary information about the relocs.
1144  * Since different linkers tend to emit the sections in
1145  * different orders we use the section names in the output.
1146  */
1147 static int do_reloc_info(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
1148                                 const char *symname)
1149 {
1150         printf("%s\t%s\t%s\t%s\n",
1151                 sec_name(sec->shdr.sh_info),
1152                 rel_type(ELF_R_TYPE(rel->r_info)),
1153                 symname,
1154                 sec_name(sym_index(sym)));
1155         return 0;
1156 }
1157
1158 static void print_reloc_info(void)
1159 {
1160         printf("reloc section\treloc type\tsymbol\tsymbol section\n");
1161         walk_relocs(do_reloc_info);
1162 }
1163
1164 #if ELF_BITS == 64
1165 # define process process_64
1166 #else
1167 # define process process_32
1168 #endif
1169
1170 void process(FILE *fp, int use_real_mode, int as_text,
1171              int show_absolute_syms, int show_absolute_relocs,
1172              int show_reloc_info)
1173 {
1174         regex_init(use_real_mode);
1175         read_ehdr(fp);
1176         read_shdrs(fp);
1177         read_strtabs(fp);
1178         read_symtabs(fp);
1179         read_relocs(fp);
1180         if (ELF_BITS == 64)
1181                 percpu_init();
1182         if (show_absolute_syms) {
1183                 print_absolute_symbols();
1184                 return;
1185         }
1186         if (show_absolute_relocs) {
1187                 print_absolute_relocs();
1188                 return;
1189         }
1190         if (show_reloc_info) {
1191                 print_reloc_info();
1192                 return;
1193         }
1194         emit_relocs(as_text, use_real_mode);
1195 }