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 #include <tools/le_byteshift.h>
  14
  15 static void die(char *fmt, ...);
  16
  17 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
  18 static Elf32_Ehdr ehdr;
  19 static unsigned long reloc_count, reloc_idx;
  20 static unsigned long *relocs;
  21 static unsigned long reloc16_count, reloc16_idx;
  22 static unsigned long *relocs16;
  23
  24 struct section {
  25         Elf32_Shdr     shdr;
  26         struct section *link;
  27         Elf32_Sym      *symtab;
  28         Elf32_Rel      *reltab;
  29         char           *strtab;
  30 };
  31 static struct section *secs;
  32
  33 enum symtype {
  34         S_ABS,
  35         S_REL,
  36         S_SEG,
  37         S_LIN,
  38         S_NSYMTYPES
  39 };
  40
  41 static const char * const sym_regex_kernel[S_NSYMTYPES] = {
  42 /*
  43  * Following symbols have been audited. There values are constant and do
  44  * not change if bzImage is loaded at a different physical address than
  45  * the address for which it has been compiled. Don't warn user about
  46  * absolute relocations present w.r.t these symbols.
  47  */
  48         [S_ABS] =
  49         "^(xen_irq_disable_direct_reloc$|"
  50         "xen_save_fl_direct_reloc$|"
  51         "VDSO|"
  52         "__crc_)",
  53
  54 /*
  55  * These symbols are known to be relative, even if the linker marks them
  56  * as absolute (typically defined outside any section in the linker script.)
  57  */
  58         [S_REL] =
  59         "^(__init_(begin|end)|"
  60         "__x86_cpu_dev_(start|end)|"
  61         "(__parainstructions|__alt_instructions)(|_end)|"
  62         "(__iommu_table|__apicdrivers|__smp_locks)(|_end)|"
  63         "__(start|end)_pci_.*|"
  64         "__(start|end)_builtin_fw|"
  65         "__(start|stop)___ksymtab(|_gpl|_unused|_unused_gpl|_gpl_future)|"
  66         "__(start|stop)___kcrctab(|_gpl|_unused|_unused_gpl|_gpl_future)|"
  67         "__(start|stop)___param|"
  68         "__(start|stop)___modver|"
  69         "__(start|stop)___bug_table|"
  70         "__tracedata_(start|end)|"
  71         "__(start|stop)_notes|"
  72         "__end_rodata|"
  73         "__initramfs_start|"
  74         "(jiffies|jiffies_64)|"
  75         "_end)$"
  76 };
  77
  78
  79 static const char * const sym_regex_realmode[S_NSYMTYPES] = {
  80 /*
  81  * These are 16-bit segment symbols when compiling 16-bit code.
  82  */
  83         [S_SEG] =
  84         "^real_mode_seg$",
  85
  86 /*
  87  * These are offsets belonging to segments, as opposed to linear addresses,
  88  * when compiling 16-bit code.
  89  */
  90         [S_LIN] =
  91         "^pa_",
  92 };
  93
  94 static const char * const *sym_regex;
  95
  96 static regex_t sym_regex_c[S_NSYMTYPES];
  97 static int is_reloc(enum symtype type, const char *sym_name)
  98 {
  99         return sym_regex[type] &&
 100                 !regexec(&sym_regex_c[type], sym_name, 0, NULL, 0);
 101 }
 102
 103 static void regex_init(int use_real_mode)
 104 {
 105         char errbuf[128];
 106         int err;
 107         int i;
 108
 109         if (use_real_mode)
 110                 sym_regex = sym_regex_realmode;
 111         else
 112                 sym_regex = sym_regex_kernel;
 113
 114         for (i = 0; i < S_NSYMTYPES; i++) {
 115                 if (!sym_regex[i])
 116                         continue;
 117
 118                 err = regcomp(&sym_regex_c[i], sym_regex[i],
 119                               REG_EXTENDED|REG_NOSUB);
 120
 121                 if (err) {
 122                         regerror(err, &sym_regex_c[i], errbuf, sizeof errbuf);
 123                         die("%s", errbuf);
 124                 }
 125         }
 126 }
 127
 128 static void die(char *fmt, ...)
 129 {
 130         va_list ap;
 131         va_start(ap, fmt);
 132         vfprintf(stderr, fmt, ap);
 133         va_end(ap);
 134         exit(1);
 135 }
 136
 137 static const char *sym_type(unsigned type)
 138 {
 139         static const char *type_name[] = {
 140 #define SYM_TYPE(X) [X] = #X
 141                 SYM_TYPE(STT_NOTYPE),
 142                 SYM_TYPE(STT_OBJECT),
 143                 SYM_TYPE(STT_FUNC),
 144                 SYM_TYPE(STT_SECTION),
 145                 SYM_TYPE(STT_FILE),
 146                 SYM_TYPE(STT_COMMON),
 147                 SYM_TYPE(STT_TLS),
 148 #undef SYM_TYPE
 149         };
 150         const char *name = "unknown sym type name";
 151         if (type < ARRAY_SIZE(type_name)) {
 152                 name = type_name[type];
 153         }
 154         return name;
 155 }
 156
 157 static const char *sym_bind(unsigned bind)
 158 {
 159         static const char *bind_name[] = {
 160 #define SYM_BIND(X) [X] = #X
 161                 SYM_BIND(STB_LOCAL),
 162                 SYM_BIND(STB_GLOBAL),
 163                 SYM_BIND(STB_WEAK),
 164 #undef SYM_BIND
 165         };
 166         const char *name = "unknown sym bind name";
 167         if (bind < ARRAY_SIZE(bind_name)) {
 168                 name = bind_name[bind];
 169         }
 170         return name;
 171 }
 172
 173 static const char *sym_visibility(unsigned visibility)
 174 {
 175         static const char *visibility_name[] = {
 176 #define SYM_VISIBILITY(X) [X] = #X
 177                 SYM_VISIBILITY(STV_DEFAULT),
 178                 SYM_VISIBILITY(STV_INTERNAL),
 179                 SYM_VISIBILITY(STV_HIDDEN),
 180                 SYM_VISIBILITY(STV_PROTECTED),
 181 #undef SYM_VISIBILITY
 182         };
 183         const char *name = "unknown sym visibility name";
 184         if (visibility < ARRAY_SIZE(visibility_name)) {
 185                 name = visibility_name[visibility];
 186         }
 187         return name;
 188 }
 189
 190 static const char *rel_type(unsigned type)
 191 {
 192         static const char *type_name[] = {
 193 #define REL_TYPE(X) [X] = #X
 194                 REL_TYPE(R_386_NONE),
 195                 REL_TYPE(R_386_32),
 196                 REL_TYPE(R_386_PC32),
 197                 REL_TYPE(R_386_GOT32),
 198                 REL_TYPE(R_386_PLT32),
 199                 REL_TYPE(R_386_COPY),
 200                 REL_TYPE(R_386_GLOB_DAT),
 201                 REL_TYPE(R_386_JMP_SLOT),
 202                 REL_TYPE(R_386_RELATIVE),
 203                 REL_TYPE(R_386_GOTOFF),
 204                 REL_TYPE(R_386_GOTPC),
 205                 REL_TYPE(R_386_8),
 206                 REL_TYPE(R_386_PC8),
 207                 REL_TYPE(R_386_16),
 208                 REL_TYPE(R_386_PC16),
 209 #undef REL_TYPE
 210         };
 211         const char *name = "unknown type rel type name";
 212         if (type < ARRAY_SIZE(type_name) && type_name[type]) {
 213                 name = type_name[type];
 214         }
 215         return name;
 216 }
 217
 218 static const char *sec_name(unsigned shndx)
 219 {
 220         const char *sec_strtab;
 221         const char *name;
 222         sec_strtab = secs[ehdr.e_shstrndx].strtab;
 223         name = "<noname>";
 224         if (shndx < ehdr.e_shnum) {
 225                 name = sec_strtab + secs[shndx].shdr.sh_name;
 226         }
 227         else if (shndx == SHN_ABS) {
 228                 name = "ABSOLUTE";
 229         }
 230         else if (shndx == SHN_COMMON) {
 231                 name = "COMMON";
 232         }
 233         return name;
 234 }
 235
 236 static const char *sym_name(const char *sym_strtab, Elf32_Sym *sym)
 237 {
 238         const char *name;
 239         name = "<noname>";
 240         if (sym->st_name) {
 241                 name = sym_strtab + sym->st_name;
 242         }
 243         else {
 244                 name = sec_name(sym->st_shndx);
 245         }
 246         return name;
 247 }
 248
 249
 250
 251 #if BYTE_ORDER == LITTLE_ENDIAN
 252 #define le16_to_cpu(val) (val)
 253 #define le32_to_cpu(val) (val)
 254 #endif
 255 #if BYTE_ORDER == BIG_ENDIAN
 256 #define le16_to_cpu(val) bswap_16(val)
 257 #define le32_to_cpu(val) bswap_32(val)
 258 #endif
 259
 260 static uint16_t elf16_to_cpu(uint16_t val)
 261 {
 262         return le16_to_cpu(val);
 263 }
 264
 265 static uint32_t elf32_to_cpu(uint32_t val)
 266 {
 267         return le32_to_cpu(val);
 268 }
 269
 270 static void read_ehdr(FILE *fp)
 271 {
 272         if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
 273                 die("Cannot read ELF header: %s\n",
 274                         strerror(errno));
 275         }
 276         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) {
 277                 die("No ELF magic\n");
 278         }
 279         if (ehdr.e_ident[EI_CLASS] != ELFCLASS32) {
 280                 die("Not a 32 bit executable\n");
 281         }
 282         if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
 283                 die("Not a LSB ELF executable\n");
 284         }
 285         if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
 286                 die("Unknown ELF version\n");
 287         }
 288         /* Convert the fields to native endian */
 289         ehdr.e_type      = elf16_to_cpu(ehdr.e_type);
 290         ehdr.e_machine   = elf16_to_cpu(ehdr.e_machine);
 291         ehdr.e_version   = elf32_to_cpu(ehdr.e_version);
 292         ehdr.e_entry     = elf32_to_cpu(ehdr.e_entry);
 293         ehdr.e_phoff     = elf32_to_cpu(ehdr.e_phoff);
 294         ehdr.e_shoff     = elf32_to_cpu(ehdr.e_shoff);
 295         ehdr.e_flags     = elf32_to_cpu(ehdr.e_flags);
 296         ehdr.e_ehsize    = elf16_to_cpu(ehdr.e_ehsize);
 297         ehdr.e_phentsize = elf16_to_cpu(ehdr.e_phentsize);
 298         ehdr.e_phnum     = elf16_to_cpu(ehdr.e_phnum);
 299         ehdr.e_shentsize = elf16_to_cpu(ehdr.e_shentsize);
 300         ehdr.e_shnum     = elf16_to_cpu(ehdr.e_shnum);
 301         ehdr.e_shstrndx  = elf16_to_cpu(ehdr.e_shstrndx);
 302
 303         if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
 304                 die("Unsupported ELF header type\n");
 305         }
 306         if (ehdr.e_machine != EM_386) {
 307                 die("Not for x86\n");
 308         }
 309         if (ehdr.e_version != EV_CURRENT) {
 310                 die("Unknown ELF version\n");
 311         }
 312         if (ehdr.e_ehsize != sizeof(Elf32_Ehdr)) {
 313                 die("Bad Elf header size\n");
 314         }
 315         if (ehdr.e_phentsize != sizeof(Elf32_Phdr)) {
 316                 die("Bad program header entry\n");
 317         }
 318         if (ehdr.e_shentsize != sizeof(Elf32_Shdr)) {
 319                 die("Bad section header entry\n");
 320         }
 321         if (ehdr.e_shstrndx >= ehdr.e_shnum) {
 322                 die("String table index out of bounds\n");
 323         }
 324 }
 325
 326 static void read_shdrs(FILE *fp)
 327 {
 328         int i;
 329         Elf32_Shdr shdr;
 330
 331         secs = calloc(ehdr.e_shnum, sizeof(struct section));
 332         if (!secs) {
 333                 die("Unable to allocate %d section headers\n",
 334                     ehdr.e_shnum);
 335         }
 336         if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
 337                 die("Seek to %d failed: %s\n",
 338                         ehdr.e_shoff, strerror(errno));
 339         }
 340         for (i = 0; i < ehdr.e_shnum; i++) {
 341                 struct section *sec = &secs[i];
 342                 if (fread(&shdr, sizeof shdr, 1, fp) != 1)
 343                         die("Cannot read ELF section headers %d/%d: %s\n",
 344                             i, ehdr.e_shnum, strerror(errno));
 345                 sec->shdr.sh_name      = elf32_to_cpu(shdr.sh_name);
 346                 sec->shdr.sh_type      = elf32_to_cpu(shdr.sh_type);
 347                 sec->shdr.sh_flags     = elf32_to_cpu(shdr.sh_flags);
 348                 sec->shdr.sh_addr      = elf32_to_cpu(shdr.sh_addr);
 349                 sec->shdr.sh_offset    = elf32_to_cpu(shdr.sh_offset);
 350                 sec->shdr.sh_size      = elf32_to_cpu(shdr.sh_size);
 351                 sec->shdr.sh_link      = elf32_to_cpu(shdr.sh_link);
 352                 sec->shdr.sh_info      = elf32_to_cpu(shdr.sh_info);
 353                 sec->shdr.sh_addralign = elf32_to_cpu(shdr.sh_addralign);
 354                 sec->shdr.sh_entsize   = elf32_to_cpu(shdr.sh_entsize);
 355                 if (sec->shdr.sh_link < ehdr.e_shnum)
 356                         sec->link = &secs[sec->shdr.sh_link];
 357         }
 358
 359 }
 360
 361 static void read_strtabs(FILE *fp)
 362 {
 363         int i;
 364         for (i = 0; i < ehdr.e_shnum; i++) {
 365                 struct section *sec = &secs[i];
 366                 if (sec->shdr.sh_type != SHT_STRTAB) {
 367                         continue;
 368                 }
 369                 sec->strtab = malloc(sec->shdr.sh_size);
 370                 if (!sec->strtab) {
 371                         die("malloc of %d bytes for strtab failed\n",
 372                                 sec->shdr.sh_size);
 373                 }
 374                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 375                         die("Seek to %d failed: %s\n",
 376                                 sec->shdr.sh_offset, strerror(errno));
 377                 }
 378                 if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
 379                     != sec->shdr.sh_size) {
 380                         die("Cannot read symbol table: %s\n",
 381                                 strerror(errno));
 382                 }
 383         }
 384 }
 385
 386 static void read_symtabs(FILE *fp)
 387 {
 388         int i,j;
 389         for (i = 0; i < ehdr.e_shnum; i++) {
 390                 struct section *sec = &secs[i];
 391                 if (sec->shdr.sh_type != SHT_SYMTAB) {
 392                         continue;
 393                 }
 394                 sec->symtab = malloc(sec->shdr.sh_size);
 395                 if (!sec->symtab) {
 396                         die("malloc of %d bytes for symtab failed\n",
 397                                 sec->shdr.sh_size);
 398                 }
 399                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 400                         die("Seek to %d failed: %s\n",
 401                                 sec->shdr.sh_offset, strerror(errno));
 402                 }
 403                 if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
 404                     != sec->shdr.sh_size) {
 405                         die("Cannot read symbol table: %s\n",
 406                                 strerror(errno));
 407                 }
 408                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
 409                         Elf32_Sym *sym = &sec->symtab[j];
 410                         sym->st_name  = elf32_to_cpu(sym->st_name);
 411                         sym->st_value = elf32_to_cpu(sym->st_value);
 412                         sym->st_size  = elf32_to_cpu(sym->st_size);
 413                         sym->st_shndx = elf16_to_cpu(sym->st_shndx);
 414                 }
 415         }
 416 }
 417
 418
 419 static void read_relocs(FILE *fp)
 420 {
 421         int i,j;
 422         for (i = 0; i < ehdr.e_shnum; i++) {
 423                 struct section *sec = &secs[i];
 424                 if (sec->shdr.sh_type != SHT_REL) {
 425                         continue;
 426                 }
 427                 sec->reltab = malloc(sec->shdr.sh_size);
 428                 if (!sec->reltab) {
 429                         die("malloc of %d bytes for relocs failed\n",
 430                                 sec->shdr.sh_size);
 431                 }
 432                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 433                         die("Seek to %d failed: %s\n",
 434                                 sec->shdr.sh_offset, strerror(errno));
 435                 }
 436                 if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
 437                     != sec->shdr.sh_size) {
 438                         die("Cannot read symbol table: %s\n",
 439                                 strerror(errno));
 440                 }
 441                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
 442                         Elf32_Rel *rel = &sec->reltab[j];
 443                         rel->r_offset = elf32_to_cpu(rel->r_offset);
 444                         rel->r_info   = elf32_to_cpu(rel->r_info);
 445                 }
 446         }
 447 }
 448
 449
 450 static void print_absolute_symbols(void)
 451 {
 452         int i;
 453         printf("Absolute symbols\n");
 454         printf(" Num:    Value Size  Type       Bind        Visibility  Name\n");
 455         for (i = 0; i < ehdr.e_shnum; i++) {
 456                 struct section *sec = &secs[i];
 457                 char *sym_strtab;
 458                 int j;
 459
 460                 if (sec->shdr.sh_type != SHT_SYMTAB) {
 461                         continue;
 462                 }
 463                 sym_strtab = sec->link->strtab;
 464                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
 465                         Elf32_Sym *sym;
 466                         const char *name;
 467                         sym = &sec->symtab[j];
 468                         name = sym_name(sym_strtab, sym);
 469                         if (sym->st_shndx != SHN_ABS) {
 470                                 continue;
 471                         }
 472                         printf("%5d %08x %5d %10s %10s %12s %s\n",
 473                                 j, sym->st_value, sym->st_size,
 474                                 sym_type(ELF32_ST_TYPE(sym->st_info)),
 475                                 sym_bind(ELF32_ST_BIND(sym->st_info)),
 476                                 sym_visibility(ELF32_ST_VISIBILITY(sym->st_other)),
 477                                 name);
 478                 }
 479         }
 480         printf("\n");
 481 }
 482
 483 static void print_absolute_relocs(void)
 484 {
 485         int i, printed = 0;
 486
 487         for (i = 0; i < ehdr.e_shnum; i++) {
 488                 struct section *sec = &secs[i];
 489                 struct section *sec_applies, *sec_symtab;
 490                 char *sym_strtab;
 491                 Elf32_Sym *sh_symtab;
 492                 int j;
 493                 if (sec->shdr.sh_type != SHT_REL) {
 494                         continue;
 495                 }
 496                 sec_symtab  = sec->link;
 497                 sec_applies = &secs[sec->shdr.sh_info];
 498                 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
 499                         continue;
 500                 }
 501                 sh_symtab  = sec_symtab->symtab;
 502                 sym_strtab = sec_symtab->link->strtab;
 503                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
 504                         Elf32_Rel *rel;
 505                         Elf32_Sym *sym;
 506                         const char *name;
 507                         rel = &sec->reltab[j];
 508                         sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
 509                         name = sym_name(sym_strtab, sym);
 510                         if (sym->st_shndx != SHN_ABS) {
 511                                 continue;
 512                         }
 513
 514                         /* Absolute symbols are not relocated if bzImage is
 515                          * loaded at a non-compiled address. Display a warning
 516                          * to user at compile time about the absolute
 517                          * relocations present.
 518                          *
 519                          * User need to audit the code to make sure
 520                          * some symbols which should have been section
 521                          * relative have not become absolute because of some
 522                          * linker optimization or wrong programming usage.
 523                          *
 524                          * Before warning check if this absolute symbol
 525                          * relocation is harmless.
 526                          */
 527                         if (is_reloc(S_ABS, name) || is_reloc(S_REL, name))
 528                                 continue;
 529
 530                         if (!printed) {
 531                                 printf("WARNING: Absolute relocations"
 532                                         " present\n");
 533                                 printf("Offset     Info     Type     Sym.Value "
 534                                         "Sym.Name\n");
 535                                 printed = 1;
 536                         }
 537
 538                         printf("%08x %08x %10s %08x  %s\n",
 539                                 rel->r_offset,
 540                                 rel->r_info,
 541                                 rel_type(ELF32_R_TYPE(rel->r_info)),
 542                                 sym->st_value,
 543                                 name);
 544                 }
 545         }
 546
 547         if (printed)
 548                 printf("\n");
 549 }
 550
 551 static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym),
 552                         int use_real_mode)
 553 {
 554         int i;
 555         /* Walk through the relocations */
 556         for (i = 0; i < ehdr.e_shnum; i++) {
 557                 char *sym_strtab;
 558                 Elf32_Sym *sh_symtab;
 559                 struct section *sec_applies, *sec_symtab;
 560                 int j;
 561                 struct section *sec = &secs[i];
 562
 563                 if (sec->shdr.sh_type != SHT_REL) {
 564                         continue;
 565                 }
 566                 sec_symtab  = sec->link;
 567                 sec_applies = &secs[sec->shdr.sh_info];
 568                 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
 569                         continue;
 570                 }
 571                 sh_symtab = sec_symtab->symtab;
 572                 sym_strtab = sec_symtab->link->strtab;
 573                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
 574                         Elf32_Rel *rel;
 575                         Elf32_Sym *sym;
 576                         unsigned r_type;
 577                         const char *symname;
 578                         int shn_abs;
 579
 580                         rel = &sec->reltab[j];
 581                         sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
 582                         r_type = ELF32_R_TYPE(rel->r_info);
 583
 584                         shn_abs = sym->st_shndx == SHN_ABS;
 585
 586                         switch (r_type) {
 587                         case R_386_NONE:
 588                         case R_386_PC32:
 589                         case R_386_PC16:
 590                         case R_386_PC8:
 591                                 /*
 592                                  * NONE can be ignored and and PC relative
 593                                  * relocations don't need to be adjusted.
 594                                  */
 595                                 break;
 596
 597                         case R_386_16:
 598                                 symname = sym_name(sym_strtab, sym);
 599                                 if (!use_real_mode)
 600                                         goto bad;
 601                                 if (shn_abs) {
 602                                         if (is_reloc(S_ABS, symname))
 603                                                 break;
 604                                         else if (!is_reloc(S_SEG, symname))
 605                                                 goto bad;
 606                                 } else {
 607                                         if (is_reloc(S_LIN, symname))
 608                                                 goto bad;
 609                                         else
 610                                                 break;
 611                                 }
 612                                 visit(rel, sym);
 613                                 break;
 614
 615                         case R_386_32:
 616                                 symname = sym_name(sym_strtab, sym);
 617                                 if (shn_abs) {
 618                                         if (is_reloc(S_ABS, symname))
 619                                                 break;
 620                                         else if (!is_reloc(S_REL, symname))
 621                                                 goto bad;
 622                                 } else {
 623                                         if (use_real_mode &&
 624                                             !is_reloc(S_LIN, symname))
 625                                                 break;
 626                                 }
 627                                 visit(rel, sym);
 628                                 break;
 629                         default:
 630                                 die("Unsupported relocation type: %s (%d)\n",
 631                                     rel_type(r_type), r_type);
 632                                 break;
 633                         bad:
 634                                 symname = sym_name(sym_strtab, sym);
 635                                 die("Invalid %s %s relocation: %s\n",
 636                                     shn_abs ? "absolute" : "relative",
 637                                     rel_type(r_type), symname);
 638                         }
 639                 }
 640         }
 641 }
 642
 643 static void count_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
 644 {
 645         if (ELF32_R_TYPE(rel->r_info) == R_386_16)
 646                 reloc16_count++;
 647         else
 648                 reloc_count++;
 649 }
 650
 651 static void collect_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
 652 {
 653         /* Remember the address that needs to be adjusted. */
 654         if (ELF32_R_TYPE(rel->r_info) == R_386_16)
 655                 relocs16[reloc16_idx++] = rel->r_offset;
 656         else
 657                 relocs[reloc_idx++] = rel->r_offset;
 658 }
 659
 660 static int cmp_relocs(const void *va, const void *vb)
 661 {
 662         const unsigned long *a, *b;
 663         a = va; b = vb;
 664         return (*a == *b)? 0 : (*a > *b)? 1 : -1;
 665 }
 666
 667 static int write32(unsigned int v, FILE *f)
 668 {
 669         unsigned char buf[4];
 670
 671         put_unaligned_le32(v, buf);
 672         return fwrite(buf, 1, 4, f) == 4 ? 0 : -1;
 673 }
 674
 675 static void emit_relocs(int as_text, int use_real_mode)
 676 {
 677         int i;
 678         /* Count how many relocations I have and allocate space for them. */
 679         reloc_count = 0;
 680         walk_relocs(count_reloc, use_real_mode);
 681         relocs = malloc(reloc_count * sizeof(relocs[0]));
 682         if (!relocs) {
 683                 die("malloc of %d entries for relocs failed\n",
 684                         reloc_count);
 685         }
 686
 687         relocs16 = malloc(reloc16_count * sizeof(relocs[0]));
 688         if (!relocs16) {
 689                 die("malloc of %d entries for relocs16 failed\n",
 690                         reloc16_count);
 691         }
 692         /* Collect up the relocations */
 693         reloc_idx = 0;
 694         walk_relocs(collect_reloc, use_real_mode);
 695
 696         if (reloc16_count && !use_real_mode)
 697                 die("Segment relocations found but --realmode not specified\n");
 698
 699         /* Order the relocations for more efficient processing */
 700         qsort(relocs, reloc_count, sizeof(relocs[0]), cmp_relocs);
 701         qsort(relocs16, reloc16_count, sizeof(relocs16[0]), cmp_relocs);
 702
 703         /* Print the relocations */
 704         if (as_text) {
 705                 /* Print the relocations in a form suitable that
 706                  * gas will like.
 707                  */
 708                 printf(".section \".data.reloc\",\"a\"\n");
 709                 printf(".balign 4\n");
 710                 if (use_real_mode) {
 711                         printf("\t.long %lu\n", reloc16_count);
 712                         for (i = 0; i < reloc16_count; i++)
 713                                 printf("\t.long 0x%08lx\n", relocs16[i]);
 714                         printf("\t.long %lu\n", reloc_count);
 715                         for (i = 0; i < reloc_count; i++) {
 716                                 printf("\t.long 0x%08lx\n", relocs[i]);
 717                         }
 718                 } else {
 719                         /* Print a stop */
 720                         printf("\t.long 0x%08lx\n", (unsigned long)0);
 721                         for (i = 0; i < reloc_count; i++) {
 722                                 printf("\t.long 0x%08lx\n", relocs[i]);
 723                         }
 724                 }
 725
 726                 printf("\n");
 727         }
 728         else {
 729                 if (use_real_mode) {
 730                         write32(reloc16_count, stdout);
 731                         for (i = 0; i < reloc16_count; i++)
 732                                 write32(relocs16[i], stdout);
 733                         write32(reloc_count, stdout);
 734
 735                         /* Now print each relocation */
 736                         for (i = 0; i < reloc_count; i++)
 737                                 write32(relocs[i], stdout);
 738                 } else {
 739                         /* Print a stop */
 740                         write32(0, stdout);
 741
 742                         /* Now print each relocation */
 743                         for (i = 0; i < reloc_count; i++) {
 744                                 write32(relocs[i], stdout);
 745                         }
 746                 }
 747         }
 748 }
 749
 750 static void usage(void)
 751 {
 752         die("relocs [--abs-syms|--abs-relocs|--text|--realmode] vmlinux\n");
 753 }
 754
 755 int main(int argc, char **argv)
 756 {
 757         int show_absolute_syms, show_absolute_relocs;
 758         int as_text, use_real_mode;
 759         const char *fname;
 760         FILE *fp;
 761         int i;
 762
 763         show_absolute_syms = 0;
 764         show_absolute_relocs = 0;
 765         as_text = 0;
 766         use_real_mode = 0;
 767         fname = NULL;
 768         for (i = 1; i < argc; i++) {
 769                 char *arg = argv[i];
 770                 if (*arg == '-') {
 771                         if (strcmp(arg, "--abs-syms") == 0) {
 772                                 show_absolute_syms = 1;
 773                                 continue;
 774                         }
 775                         if (strcmp(arg, "--abs-relocs") == 0) {
 776                                 show_absolute_relocs = 1;
 777                                 continue;
 778                         }
 779                         if (strcmp(arg, "--text") == 0) {
 780                                 as_text = 1;
 781                                 continue;
 782                         }
 783                         if (strcmp(arg, "--realmode") == 0) {
 784                                 use_real_mode = 1;
 785                                 continue;
 786                         }
 787                 }
 788                 else if (!fname) {
 789                         fname = arg;
 790                         continue;
 791                 }
 792                 usage();
 793         }
 794         if (!fname) {
 795                 usage();
 796         }
 797         regex_init(use_real_mode);
 798         fp = fopen(fname, "r");
 799         if (!fp) {
 800                 die("Cannot open %s: %s\n",
 801                         fname, strerror(errno));
 802         }
 803         read_ehdr(fp);
 804         read_shdrs(fp);
 805         read_strtabs(fp);
 806         read_symtabs(fp);
 807         read_relocs(fp);
 808         if (show_absolute_syms) {
 809                 print_absolute_symbols();
 810                 return 0;
 811         }
 812         if (show_absolute_relocs) {
 813                 print_absolute_relocs();
 814                 return 0;
 815         }
 816         emit_relocs(as_text, use_real_mode);
 817         return 0;
 818 }