arch/x86/tools/relocs.c

   1 #include <stdio.h>
   2 #include <stdarg.h>
   3 #include <stdlib.h>
   4 #include <stdint.h>
   5 #include <string.h>
   6 #include <errno.h>
   7 #include <unistd.h>
   8 #include <elf.h>
   9 #include <byteswap.h>
  10 #define USE_BSD
  11 #include <endian.h>
  12 #include <regex.h>
  13
  14 static void die(char *fmt, ...);
  15
  16 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
  17 static Elf32_Ehdr ehdr;
  18 static unsigned long reloc_count, reloc_idx;
  19 static unsigned long *relocs;
  20 static unsigned long reloc16_count, reloc16_idx;
  21 static unsigned long *relocs16;
  22
  23 struct section {
  24         Elf32_Shdr     shdr;
  25         struct section *link;
  26         Elf32_Sym      *symtab;
  27         Elf32_Rel      *reltab;
  28         char           *strtab;
  29 };
  30 static struct section *secs;
  31
  32 enum symtype {
  33         S_ABS,
  34         S_REL,
  35         S_SEG,
  36         S_LIN,
  37         S_NSYMTYPES
  38 };
  39
  40 static const char * const sym_regex_kernel[S_NSYMTYPES] = {
  41 /*
  42  * Following symbols have been audited. There values are constant and do
  43  * not change if bzImage is loaded at a different physical address than
  44  * the address for which it has been compiled. Don't warn user about
  45  * absolute relocations present w.r.t these symbols.
  46  */
  47         [S_ABS] =
  48         "^(xen_irq_disable_direct_reloc$|"
  49         "xen_save_fl_direct_reloc$|"
  50         "VDSO|"
  51         "__crc_)",
  52
  53 /*
  54  * These symbols are known to be relative, even if the linker marks them
  55  * as absolute (typically defined outside any section in the linker script.)
  56  */
  57         [S_REL] =
  58         "^(__init_(begin|end)|"
  59         "__x86_cpu_dev_(start|end)|"
  60         "(__parainstructions|__alt_instructions)(|_end)|"
  61         "(__iommu_table|__apicdrivers|__smp_locks)(|_end)|"
  62         "__(start|end)_pci_.*|"
  63         "__(start|end)_builtin_fw|"
  64         "__(start|stop)___ksymtab(|_gpl|_unused|_unused_gpl|_gpl_future)|"
  65         "__(start|stop)___kcrctab(|_gpl|_unused|_unused_gpl|_gpl_future)|"
  66         "__(start|stop)___param|"
  67         "__(start|stop)___modver|"
  68         "__(start|stop)___bug_table|"
  69         "__tracedata_(start|end)|"
  70         "__(start|stop)_notes|"
  71         "__end_rodata|"
  72         "__initramfs_start|"
  73         "(jiffies|jiffies_64)|"
  74         "_end)$"
  75 };
  76
  77
  78 static const char * const sym_regex_realmode[S_NSYMTYPES] = {
  79 /*
  80  * These are 16-bit segment symbols when compiling 16-bit code.
  81  */
  82         [S_SEG] =
  83         "^real_mode_seg$",
  84
  85 /*
  86  * These are offsets belonging to segments, as opposed to linear addresses,
  87  * when compiling 16-bit code.
  88  */
  89         [S_LIN] =
  90         "^pa_",
  91 };
  92
  93 static const char * const *sym_regex;
  94
  95 static regex_t sym_regex_c[S_NSYMTYPES];
  96 static int is_reloc(enum symtype type, const char *sym_name)
  97 {
  98         return sym_regex[type] &&
  99                 !regexec(&sym_regex_c[type], sym_name, 0, NULL, 0);
 100 }
 101
 102 static void regex_init(int use_real_mode)
 103 {
 104         char errbuf[128];
 105         int err;
 106         int i;
 107
 108         if (use_real_mode)
 109                 sym_regex = sym_regex_realmode;
 110         else
 111                 sym_regex = sym_regex_kernel;
 112
 113         for (i = 0; i < S_NSYMTYPES; i++) {
 114                 if (!sym_regex[i])
 115                         continue;
 116
 117                 err = regcomp(&sym_regex_c[i], sym_regex[i],
 118                               REG_EXTENDED|REG_NOSUB);
 119
 120                 if (err) {
 121                         regerror(err, &sym_regex_c[i], errbuf, sizeof errbuf);
 122                         die("%s", errbuf);
 123                 }
 124         }
 125 }
 126
 127 static void die(char *fmt, ...)
 128 {
 129         va_list ap;
 130         va_start(ap, fmt);
 131         vfprintf(stderr, fmt, ap);
 132         va_end(ap);
 133         exit(1);
 134 }
 135
 136 static const char *sym_type(unsigned type)
 137 {
 138         static const char *type_name[] = {
 139 #define SYM_TYPE(X) [X] = #X
 140                 SYM_TYPE(STT_NOTYPE),
 141                 SYM_TYPE(STT_OBJECT),
 142                 SYM_TYPE(STT_FUNC),
 143                 SYM_TYPE(STT_SECTION),
 144                 SYM_TYPE(STT_FILE),
 145                 SYM_TYPE(STT_COMMON),
 146                 SYM_TYPE(STT_TLS),
 147 #undef SYM_TYPE
 148         };
 149         const char *name = "unknown sym type name";
 150         if (type < ARRAY_SIZE(type_name)) {
 151                 name = type_name[type];
 152         }
 153         return name;
 154 }
 155
 156 static const char *sym_bind(unsigned bind)
 157 {
 158         static const char *bind_name[] = {
 159 #define SYM_BIND(X) [X] = #X
 160                 SYM_BIND(STB_LOCAL),
 161                 SYM_BIND(STB_GLOBAL),
 162                 SYM_BIND(STB_WEAK),
 163 #undef SYM_BIND
 164         };
 165         const char *name = "unknown sym bind name";
 166         if (bind < ARRAY_SIZE(bind_name)) {
 167                 name = bind_name[bind];
 168         }
 169         return name;
 170 }
 171
 172 static const char *sym_visibility(unsigned visibility)
 173 {
 174         static const char *visibility_name[] = {
 175 #define SYM_VISIBILITY(X) [X] = #X
 176                 SYM_VISIBILITY(STV_DEFAULT),
 177                 SYM_VISIBILITY(STV_INTERNAL),
 178                 SYM_VISIBILITY(STV_HIDDEN),
 179                 SYM_VISIBILITY(STV_PROTECTED),
 180 #undef SYM_VISIBILITY
 181         };
 182         const char *name = "unknown sym visibility name";
 183         if (visibility < ARRAY_SIZE(visibility_name)) {
 184                 name = visibility_name[visibility];
 185         }
 186         return name;
 187 }
 188
 189 static const char *rel_type(unsigned type)
 190 {
 191         static const char *type_name[] = {
 192 #define REL_TYPE(X) [X] = #X
 193                 REL_TYPE(R_386_NONE),
 194                 REL_TYPE(R_386_32),
 195                 REL_TYPE(R_386_PC32),
 196                 REL_TYPE(R_386_GOT32),
 197                 REL_TYPE(R_386_PLT32),
 198                 REL_TYPE(R_386_COPY),
 199                 REL_TYPE(R_386_GLOB_DAT),
 200                 REL_TYPE(R_386_JMP_SLOT),
 201                 REL_TYPE(R_386_RELATIVE),
 202                 REL_TYPE(R_386_GOTOFF),
 203                 REL_TYPE(R_386_GOTPC),
 204                 REL_TYPE(R_386_8),
 205                 REL_TYPE(R_386_PC8),
 206                 REL_TYPE(R_386_16),
 207                 REL_TYPE(R_386_PC16),
 208 #undef REL_TYPE
 209         };
 210         const char *name = "unknown type rel type name";
 211         if (type < ARRAY_SIZE(type_name) && type_name[type]) {
 212                 name = type_name[type];
 213         }
 214         return name;
 215 }
 216
 217 static const char *sec_name(unsigned shndx)
 218 {
 219         const char *sec_strtab;
 220         const char *name;
 221         sec_strtab = secs[ehdr.e_shstrndx].strtab;
 222         name = "<noname>";
 223         if (shndx < ehdr.e_shnum) {
 224                 name = sec_strtab + secs[shndx].shdr.sh_name;
 225         }
 226         else if (shndx == SHN_ABS) {
 227                 name = "ABSOLUTE";
 228         }
 229         else if (shndx == SHN_COMMON) {
 230                 name = "COMMON";
 231         }
 232         return name;
 233 }
 234
 235 static const char *sym_name(const char *sym_strtab, Elf32_Sym *sym)
 236 {
 237         const char *name;
 238         name = "<noname>";
 239         if (sym->st_name) {
 240                 name = sym_strtab + sym->st_name;
 241         }
 242         else {
 243                 name = sec_name(sym->st_shndx);
 244         }
 245         return name;
 246 }
 247
 248
 249
 250 #if BYTE_ORDER == LITTLE_ENDIAN
 251 #define le16_to_cpu(val) (val)
 252 #define le32_to_cpu(val) (val)
 253 #endif
 254 #if BYTE_ORDER == BIG_ENDIAN
 255 #define le16_to_cpu(val) bswap_16(val)
 256 #define le32_to_cpu(val) bswap_32(val)
 257 #endif
 258
 259 static uint16_t elf16_to_cpu(uint16_t val)
 260 {
 261         return le16_to_cpu(val);
 262 }
 263
 264 static uint32_t elf32_to_cpu(uint32_t val)
 265 {
 266         return le32_to_cpu(val);
 267 }
 268
 269 static void read_ehdr(FILE *fp)
 270 {
 271         if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
 272                 die("Cannot read ELF header: %s\n",
 273                         strerror(errno));
 274         }
 275         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) {
 276                 die("No ELF magic\n");
 277         }
 278         if (ehdr.e_ident[EI_CLASS] != ELFCLASS32) {
 279                 die("Not a 32 bit executable\n");
 280         }
 281         if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
 282                 die("Not a LSB ELF executable\n");
 283         }
 284         if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
 285                 die("Unknown ELF version\n");
 286         }
 287         /* Convert the fields to native endian */
 288         ehdr.e_type      = elf16_to_cpu(ehdr.e_type);
 289         ehdr.e_machine   = elf16_to_cpu(ehdr.e_machine);
 290         ehdr.e_version   = elf32_to_cpu(ehdr.e_version);
 291         ehdr.e_entry     = elf32_to_cpu(ehdr.e_entry);
 292         ehdr.e_phoff     = elf32_to_cpu(ehdr.e_phoff);
 293         ehdr.e_shoff     = elf32_to_cpu(ehdr.e_shoff);
 294         ehdr.e_flags     = elf32_to_cpu(ehdr.e_flags);
 295         ehdr.e_ehsize    = elf16_to_cpu(ehdr.e_ehsize);
 296         ehdr.e_phentsize = elf16_to_cpu(ehdr.e_phentsize);
 297         ehdr.e_phnum     = elf16_to_cpu(ehdr.e_phnum);
 298         ehdr.e_shentsize = elf16_to_cpu(ehdr.e_shentsize);
 299         ehdr.e_shnum     = elf16_to_cpu(ehdr.e_shnum);
 300         ehdr.e_shstrndx  = elf16_to_cpu(ehdr.e_shstrndx);
 301
 302         if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
 303                 die("Unsupported ELF header type\n");
 304         }
 305         if (ehdr.e_machine != EM_386) {
 306                 die("Not for x86\n");
 307         }
 308         if (ehdr.e_version != EV_CURRENT) {
 309                 die("Unknown ELF version\n");
 310         }
 311         if (ehdr.e_ehsize != sizeof(Elf32_Ehdr)) {
 312                 die("Bad Elf header size\n");
 313         }
 314         if (ehdr.e_phentsize != sizeof(Elf32_Phdr)) {
 315                 die("Bad program header entry\n");
 316         }
 317         if (ehdr.e_shentsize != sizeof(Elf32_Shdr)) {
 318                 die("Bad section header entry\n");
 319         }
 320         if (ehdr.e_shstrndx >= ehdr.e_shnum) {
 321                 die("String table index out of bounds\n");
 322         }
 323 }
 324
 325 static void read_shdrs(FILE *fp)
 326 {
 327         int i;
 328         Elf32_Shdr shdr;
 329
 330         secs = calloc(ehdr.e_shnum, sizeof(struct section));
 331         if (!secs) {
 332                 die("Unable to allocate %d section headers\n",
 333                     ehdr.e_shnum);
 334         }
 335         if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
 336                 die("Seek to %d failed: %s\n",
 337                         ehdr.e_shoff, strerror(errno));
 338         }
 339         for (i = 0; i < ehdr.e_shnum; i++) {
 340                 struct section *sec = &secs[i];
 341                 if (fread(&shdr, sizeof shdr, 1, fp) != 1)
 342                         die("Cannot read ELF section headers %d/%d: %s\n",
 343                             i, ehdr.e_shnum, strerror(errno));
 344                 sec->shdr.sh_name      = elf32_to_cpu(shdr.sh_name);
 345                 sec->shdr.sh_type      = elf32_to_cpu(shdr.sh_type);
 346                 sec->shdr.sh_flags     = elf32_to_cpu(shdr.sh_flags);
 347                 sec->shdr.sh_addr      = elf32_to_cpu(shdr.sh_addr);
 348                 sec->shdr.sh_offset    = elf32_to_cpu(shdr.sh_offset);
 349                 sec->shdr.sh_size      = elf32_to_cpu(shdr.sh_size);
 350                 sec->shdr.sh_link      = elf32_to_cpu(shdr.sh_link);
 351                 sec->shdr.sh_info      = elf32_to_cpu(shdr.sh_info);
 352                 sec->shdr.sh_addralign = elf32_to_cpu(shdr.sh_addralign);
 353                 sec->shdr.sh_entsize   = elf32_to_cpu(shdr.sh_entsize);
 354                 if (sec->shdr.sh_link < ehdr.e_shnum)
 355                         sec->link = &secs[sec->shdr.sh_link];
 356         }
 357
 358 }
 359
 360 static void read_strtabs(FILE *fp)
 361 {
 362         int i;
 363         for (i = 0; i < ehdr.e_shnum; i++) {
 364                 struct section *sec = &secs[i];
 365                 if (sec->shdr.sh_type != SHT_STRTAB) {
 366                         continue;
 367                 }
 368                 sec->strtab = malloc(sec->shdr.sh_size);
 369                 if (!sec->strtab) {
 370                         die("malloc of %d bytes for strtab failed\n",
 371                                 sec->shdr.sh_size);
 372                 }
 373                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 374                         die("Seek to %d failed: %s\n",
 375                                 sec->shdr.sh_offset, strerror(errno));
 376                 }
 377                 if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
 378                     != sec->shdr.sh_size) {
 379                         die("Cannot read symbol table: %s\n",
 380                                 strerror(errno));
 381                 }
 382         }
 383 }
 384
 385 static void read_symtabs(FILE *fp)
 386 {
 387         int i,j;
 388         for (i = 0; i < ehdr.e_shnum; i++) {
 389                 struct section *sec = &secs[i];
 390                 if (sec->shdr.sh_type != SHT_SYMTAB) {
 391                         continue;
 392                 }
 393                 sec->symtab = malloc(sec->shdr.sh_size);
 394                 if (!sec->symtab) {
 395                         die("malloc of %d bytes for symtab failed\n",
 396                                 sec->shdr.sh_size);
 397                 }
 398                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 399                         die("Seek to %d failed: %s\n",
 400                                 sec->shdr.sh_offset, strerror(errno));
 401                 }
 402                 if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
 403                     != sec->shdr.sh_size) {
 404                         die("Cannot read symbol table: %s\n",
 405                                 strerror(errno));
 406                 }
 407                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
 408                         Elf32_Sym *sym = &sec->symtab[j];
 409                         sym->st_name  = elf32_to_cpu(sym->st_name);
 410                         sym->st_value = elf32_to_cpu(sym->st_value);
 411                         sym->st_size  = elf32_to_cpu(sym->st_size);
 412                         sym->st_shndx = elf16_to_cpu(sym->st_shndx);
 413                 }
 414         }
 415 }
 416
 417
 418 static void read_relocs(FILE *fp)
 419 {
 420         int i,j;
 421         for (i = 0; i < ehdr.e_shnum; i++) {
 422                 struct section *sec = &secs[i];
 423                 if (sec->shdr.sh_type != SHT_REL) {
 424                         continue;
 425                 }
 426                 sec->reltab = malloc(sec->shdr.sh_size);
 427                 if (!sec->reltab) {
 428                         die("malloc of %d bytes for relocs failed\n",
 429                                 sec->shdr.sh_size);
 430                 }
 431                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 432                         die("Seek to %d failed: %s\n",
 433                                 sec->shdr.sh_offset, strerror(errno));
 434                 }
 435                 if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
 436                     != sec->shdr.sh_size) {
 437                         die("Cannot read symbol table: %s\n",
 438                                 strerror(errno));
 439                 }
 440                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
 441                         Elf32_Rel *rel = &sec->reltab[j];
 442                         rel->r_offset = elf32_to_cpu(rel->r_offset);
 443                         rel->r_info   = elf32_to_cpu(rel->r_info);
 444                 }
 445         }
 446 }
 447
 448
 449 static void print_absolute_symbols(void)
 450 {
 451         int i;
 452         printf("Absolute symbols\n");
 453         printf(" Num:    Value Size  Type       Bind        Visibility  Name\n");
 454         for (i = 0; i < ehdr.e_shnum; i++) {
 455                 struct section *sec = &secs[i];
 456                 char *sym_strtab;
 457                 int j;
 458
 459                 if (sec->shdr.sh_type != SHT_SYMTAB) {
 460                         continue;
 461                 }
 462                 sym_strtab = sec->link->strtab;
 463                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
 464                         Elf32_Sym *sym;
 465                         const char *name;
 466                         sym = &sec->symtab[j];
 467                         name = sym_name(sym_strtab, sym);
 468                         if (sym->st_shndx != SHN_ABS) {
 469                                 continue;
 470                         }
 471                         printf("%5d %08x %5d %10s %10s %12s %s\n",
 472                                 j, sym->st_value, sym->st_size,
 473                                 sym_type(ELF32_ST_TYPE(sym->st_info)),
 474                                 sym_bind(ELF32_ST_BIND(sym->st_info)),
 475                                 sym_visibility(ELF32_ST_VISIBILITY(sym->st_other)),
 476                                 name);
 477                 }
 478         }
 479         printf("\n");
 480 }
 481
 482 static void print_absolute_relocs(void)
 483 {
 484         int i, printed = 0;
 485
 486         for (i = 0; i < ehdr.e_shnum; i++) {
 487                 struct section *sec = &secs[i];
 488                 struct section *sec_applies, *sec_symtab;
 489                 char *sym_strtab;
 490                 Elf32_Sym *sh_symtab;
 491                 int j;
 492                 if (sec->shdr.sh_type != SHT_REL) {
 493                         continue;
 494                 }
 495                 sec_symtab  = sec->link;
 496                 sec_applies = &secs[sec->shdr.sh_info];
 497                 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
 498                         continue;
 499                 }
 500                 sh_symtab  = sec_symtab->symtab;
 501                 sym_strtab = sec_symtab->link->strtab;
 502                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
 503                         Elf32_Rel *rel;
 504                         Elf32_Sym *sym;
 505                         const char *name;
 506                         rel = &sec->reltab[j];
 507                         sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
 508                         name = sym_name(sym_strtab, sym);
 509                         if (sym->st_shndx != SHN_ABS) {
 510                                 continue;
 511                         }
 512
 513                         /* Absolute symbols are not relocated if bzImage is
 514                          * loaded at a non-compiled address. Display a warning
 515                          * to user at compile time about the absolute
 516                          * relocations present.
 517                          *
 518                          * User need to audit the code to make sure
 519                          * some symbols which should have been section
 520                          * relative have not become absolute because of some
 521                          * linker optimization or wrong programming usage.
 522                          *
 523                          * Before warning check if this absolute symbol
 524                          * relocation is harmless.
 525                          */
 526                         if (is_reloc(S_ABS, name) || is_reloc(S_REL, name))
 527                                 continue;
 528
 529                         if (!printed) {
 530                                 printf("WARNING: Absolute relocations"
 531                                         " present\n");
 532                                 printf("Offset     Info     Type     Sym.Value "
 533                                         "Sym.Name\n");
 534                                 printed = 1;
 535                         }
 536
 537                         printf("%08x %08x %10s %08x  %s\n",
 538                                 rel->r_offset,
 539                                 rel->r_info,
 540                                 rel_type(ELF32_R_TYPE(rel->r_info)),
 541                                 sym->st_value,
 542                                 name);
 543                 }
 544         }
 545
 546         if (printed)
 547                 printf("\n");
 548 }
 549
 550 static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym),
 551                         int use_real_mode)
 552 {
 553         int i;
 554         /* Walk through the relocations */
 555         for (i = 0; i < ehdr.e_shnum; i++) {
 556                 char *sym_strtab;
 557                 Elf32_Sym *sh_symtab;
 558                 struct section *sec_applies, *sec_symtab;
 559                 int j;
 560                 struct section *sec = &secs[i];
 561
 562                 if (sec->shdr.sh_type != SHT_REL) {
 563                         continue;
 564                 }
 565                 sec_symtab  = sec->link;
 566                 sec_applies = &secs[sec->shdr.sh_info];
 567                 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
 568                         continue;
 569                 }
 570                 sh_symtab = sec_symtab->symtab;
 571                 sym_strtab = sec_symtab->link->strtab;
 572                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
 573                         Elf32_Rel *rel;
 574                         Elf32_Sym *sym;
 575                         unsigned r_type;
 576                         const char *symname;
 577                         int shn_abs;
 578
 579                         rel = &sec->reltab[j];
 580                         sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
 581                         r_type = ELF32_R_TYPE(rel->r_info);
 582
 583                         shn_abs = sym->st_shndx == SHN_ABS;
 584
 585                         switch (r_type) {
 586                         case R_386_NONE:
 587                         case R_386_PC32:
 588                         case R_386_PC16:
 589                         case R_386_PC8:
 590                                 /*
 591                                  * NONE can be ignored and and PC relative
 592                                  * relocations don't need to be adjusted.
 593                                  */
 594                                 break;
 595
 596                         case R_386_16:
 597                                 symname = sym_name(sym_strtab, sym);
 598                                 if (!use_real_mode)
 599                                         goto bad;
 600                                 if (shn_abs) {
 601                                         if (is_reloc(S_ABS, symname))
 602                                                 break;
 603                                         else if (!is_reloc(S_SEG, symname))
 604                                                 goto bad;
 605                                 } else {
 606                                         if (is_reloc(S_LIN, symname))
 607                                                 goto bad;
 608                                         else
 609                                                 break;
 610                                 }
 611                                 visit(rel, sym);
 612                                 break;
 613
 614                         case R_386_32:
 615                                 symname = sym_name(sym_strtab, sym);
 616                                 if (shn_abs) {
 617                                         if (is_reloc(S_ABS, symname))
 618                                                 break;
 619                                         else if (!is_reloc(S_REL, symname))
 620                                                 goto bad;
 621                                 } else {
 622                                         if (use_real_mode &&
 623                                             !is_reloc(S_LIN, symname))
 624                                                 break;
 625                                 }
 626                                 visit(rel, sym);
 627                                 break;
 628                         default:
 629                                 die("Unsupported relocation type: %s (%d)\n",
 630                                     rel_type(r_type), r_type);
 631                                 break;
 632                         bad:
 633                                 symname = sym_name(sym_strtab, sym);
 634                                 die("Invalid %s %s relocation: %s\n",
 635                                     shn_abs ? "absolute" : "relative",
 636                                     rel_type(r_type), symname);
 637                         }
 638                 }
 639         }
 640 }
 641
 642 static void count_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
 643 {
 644         if (ELF32_R_TYPE(rel->r_info) == R_386_16)
 645                 reloc16_count++;
 646         else
 647                 reloc_count++;
 648 }
 649
 650 static void collect_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
 651 {
 652         /* Remember the address that needs to be adjusted. */
 653         if (ELF32_R_TYPE(rel->r_info) == R_386_16)
 654                 relocs16[reloc16_idx++] = rel->r_offset;
 655         else
 656                 relocs[reloc_idx++] = rel->r_offset;
 657 }
 658
 659 static int cmp_relocs(const void *va, const void *vb)
 660 {
 661         const unsigned long *a, *b;
 662         a = va; b = vb;
 663         return (*a == *b)? 0 : (*a > *b)? 1 : -1;
 664 }
 665
 666 static int write32(unsigned int v, FILE *f)
 667 {
 668         unsigned char buf[4];
 669
 670         buf[0] = (v >>  0) & 0xff;
 671         buf[1] = (v >>  8) & 0xff;
 672         buf[2] = (v >> 16) & 0xff;
 673         buf[3] = (v >> 24) & 0xff;
 674         return fwrite(buf, 1, 4, f) == 4 ? 0 : -1;
 675 }
 676
 677 static void emit_relocs(int as_text, int use_real_mode)
 678 {
 679         int i;
 680         /* Count how many relocations I have and allocate space for them. */
 681         reloc_count = 0;
 682         walk_relocs(count_reloc, use_real_mode);
 683         relocs = malloc(reloc_count * sizeof(relocs[0]));
 684         if (!relocs) {
 685                 die("malloc of %d entries for relocs failed\n",
 686                         reloc_count);
 687         }
 688
 689         relocs16 = malloc(reloc16_count * sizeof(relocs[0]));
 690         if (!relocs16) {
 691                 die("malloc of %d entries for relocs16 failed\n",
 692                         reloc16_count);
 693         }
 694         /* Collect up the relocations */
 695         reloc_idx = 0;
 696         walk_relocs(collect_reloc, use_real_mode);
 697
 698         if (reloc16_count && !use_real_mode)
 699                 die("Segment relocations found but --realmode not specified\n");
 700
 701         /* Order the relocations for more efficient processing */
 702         qsort(relocs, reloc_count, sizeof(relocs[0]), cmp_relocs);
 703         qsort(relocs16, reloc16_count, sizeof(relocs16[0]), cmp_relocs);
 704
 705         /* Print the relocations */
 706         if (as_text) {
 707                 /* Print the relocations in a form suitable that
 708                  * gas will like.
 709                  */
 710                 printf(".section \".data.reloc\",\"a\"\n");
 711                 printf(".balign 4\n");
 712                 if (use_real_mode) {
 713                         printf("\t.long %lu\n", reloc16_count);
 714                         for (i = 0; i < reloc16_count; i++)
 715                                 printf("\t.long 0x%08lx\n", relocs16[i]);
 716                         printf("\t.long %lu\n", reloc_count);
 717                         for (i = 0; i < reloc_count; i++) {
 718                                 printf("\t.long 0x%08lx\n", relocs[i]);
 719                         }
 720                 } else {
 721                         /* Print a stop */
 722                         printf("\t.long 0x%08lx\n", (unsigned long)0);
 723                         for (i = 0; i < reloc_count; i++) {
 724                                 printf("\t.long 0x%08lx\n", relocs[i]);
 725                         }
 726                 }
 727
 728                 printf("\n");
 729         }
 730         else {
 731                 if (use_real_mode) {
 732                         write32(reloc16_count, stdout);
 733                         for (i = 0; i < reloc16_count; i++)
 734                                 write32(relocs16[i], stdout);
 735                         write32(reloc_count, stdout);
 736
 737                         /* Now print each relocation */
 738                         for (i = 0; i < reloc_count; i++)
 739                                 write32(relocs[i], stdout);
 740                 } else {
 741                         /* Print a stop */
 742                         write32(0, stdout);
 743
 744                         /* Now print each relocation */
 745                         for (i = 0; i < reloc_count; i++) {
 746                                 write32(relocs[i], stdout);
 747                         }
 748                 }
 749         }
 750 }
 751
 752 static void usage(void)
 753 {
 754         die("relocs [--abs-syms|--abs-relocs|--text|--realmode] vmlinux\n");
 755 }
 756
 757 int main(int argc, char **argv)
 758 {
 759         int show_absolute_syms, show_absolute_relocs;
 760         int as_text, use_real_mode;
 761         const char *fname;
 762         FILE *fp;
 763         int i;
 764
 765         show_absolute_syms = 0;
 766         show_absolute_relocs = 0;
 767         as_text = 0;
 768         use_real_mode = 0;
 769         fname = NULL;
 770         for (i = 1; i < argc; i++) {
 771                 char *arg = argv[i];
 772                 if (*arg == '-') {
 773                         if (strcmp(arg, "--abs-syms") == 0) {
 774                                 show_absolute_syms = 1;
 775                                 continue;
 776                         }
 777                         if (strcmp(arg, "--abs-relocs") == 0) {
 778                                 show_absolute_relocs = 1;
 779                                 continue;
 780                         }
 781                         if (strcmp(arg, "--text") == 0) {
 782                                 as_text = 1;
 783                                 continue;
 784                         }
 785                         if (strcmp(arg, "--realmode") == 0) {
 786                                 use_real_mode = 1;
 787                                 continue;
 788                         }
 789                 }
 790                 else if (!fname) {
 791                         fname = arg;
 792                         continue;
 793                 }
 794                 usage();
 795         }
 796         if (!fname) {
 797                 usage();
 798         }
 799         regex_init(use_real_mode);
 800         fp = fopen(fname, "r");
 801         if (!fp) {
 802                 die("Cannot open %s: %s\n",
 803                         fname, strerror(errno));
 804         }
 805         read_ehdr(fp);
 806         read_shdrs(fp);
 807         read_strtabs(fp);
 808         read_symtabs(fp);
 809         read_relocs(fp);
 810         if (show_absolute_syms) {
 811                 print_absolute_symbols();
 812                 return 0;
 813         }
 814         if (show_absolute_relocs) {
 815                 print_absolute_relocs();
 816                 return 0;
 817         }
 818         emit_relocs(as_text, use_real_mode);
 819         return 0;
 820 }