scripts/mod/modpost.c

   1 /* Postprocess module symbol versions
   2  *
   3  * Copyright 2003       Kai Germaschewski
   4  * Copyright 2002-2004  Rusty Russell, IBM Corporation
   5  * Copyright 2006-2008  Sam Ravnborg
   6  * Based in part on module-init-tools/depmod.c,file2alias
   7  *
   8  * This software may be used and distributed according to the terms
   9  * of the GNU General Public License, incorporated herein by reference.
  10  *
  11  * Usage: modpost vmlinux module1.o module2.o ...
  12  */
  13
  14 #define _GNU_SOURCE
  15 #include <stdio.h>
  16 #include <ctype.h>
  17 #include <string.h>
  18 #include <limits.h>
  19 #include <stdbool.h>
  20 #include <errno.h>
  21 #include "modpost.h"
  22 #include "../../include/linux/license.h"
  23
  24 /* Are we using CONFIG_MODVERSIONS? */
  25 static int modversions = 0;
  26 /* Warn about undefined symbols? (do so if we have vmlinux) */
  27 static int have_vmlinux = 0;
  28 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */
  29 static int all_versions = 0;
  30 /* If we are modposting external module set to 1 */
  31 static int external_module = 0;
  32 /* Warn about section mismatch in vmlinux if set to 1 */
  33 static int vmlinux_section_warnings = 1;
  34 /* Only warn about unresolved symbols */
  35 static int warn_unresolved = 0;
  36 /* How a symbol is exported */
  37 static int sec_mismatch_count = 0;
  38 static int sec_mismatch_verbose = 1;
  39 static int sec_mismatch_fatal = 0;
  40 /* ignore missing files */
  41 static int ignore_missing_files;
  42
  43 enum export {
  44         export_plain,      export_unused,     export_gpl,
  45         export_unused_gpl, export_gpl_future, export_unknown
  46 };
  47
  48 /* In kernel, this size is defined in linux/module.h;
  49  * here we use Elf_Addr instead of long for covering cross-compile
  50  */
  51
  52 #define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
  53
  54 #define PRINTF __attribute__ ((format (printf, 1, 2)))
  55
  56 PRINTF void fatal(const char *fmt, ...)
  57 {
  58         va_list arglist;
  59
  60         fprintf(stderr, "FATAL: ");
  61
  62         va_start(arglist, fmt);
  63         vfprintf(stderr, fmt, arglist);
  64         va_end(arglist);
  65
  66         exit(1);
  67 }
  68
  69 PRINTF void warn(const char *fmt, ...)
  70 {
  71         va_list arglist;
  72
  73         fprintf(stderr, "WARNING: ");
  74
  75         va_start(arglist, fmt);
  76         vfprintf(stderr, fmt, arglist);
  77         va_end(arglist);
  78 }
  79
  80 PRINTF void merror(const char *fmt, ...)
  81 {
  82         va_list arglist;
  83
  84         fprintf(stderr, "ERROR: ");
  85
  86         va_start(arglist, fmt);
  87         vfprintf(stderr, fmt, arglist);
  88         va_end(arglist);
  89 }
  90
  91 static inline bool strends(const char *str, const char *postfix)
  92 {
  93         if (strlen(str) < strlen(postfix))
  94                 return false;
  95
  96         return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0;
  97 }
  98
  99 static int is_vmlinux(const char *modname)
 100 {
 101         const char *myname;
 102
 103         myname = strrchr(modname, '/');
 104         if (myname)
 105                 myname++;
 106         else
 107                 myname = modname;
 108
 109         return (strcmp(myname, "vmlinux") == 0) ||
 110                (strcmp(myname, "vmlinux.o") == 0);
 111 }
 112
 113 void *do_nofail(void *ptr, const char *expr)
 114 {
 115         if (!ptr)
 116                 fatal("modpost: Memory allocation failure: %s.\n", expr);
 117
 118         return ptr;
 119 }
 120
 121 /* A list of all modules we processed */
 122 static struct module *modules;
 123
 124 static struct module *find_module(const char *modname)
 125 {
 126         struct module *mod;
 127
 128         for (mod = modules; mod; mod = mod->next)
 129                 if (strcmp(mod->name, modname) == 0)
 130                         break;
 131         return mod;
 132 }
 133
 134 static struct module *new_module(const char *modname)
 135 {
 136         struct module *mod;
 137         char *p;
 138
 139         mod = NOFAIL(malloc(sizeof(*mod)));
 140         memset(mod, 0, sizeof(*mod));
 141         p = NOFAIL(strdup(modname));
 142
 143         /* strip trailing .o */
 144         if (strends(p, ".o")) {
 145                 p[strlen(p) - 2] = '\0';
 146                 mod->is_dot_o = 1;
 147         }
 148
 149         /* add to list */
 150         mod->name = p;
 151         mod->gpl_compatible = -1;
 152         mod->next = modules;
 153         modules = mod;
 154
 155         return mod;
 156 }
 157
 158 /* A hash of all exported symbols,
 159  * struct symbol is also used for lists of unresolved symbols */
 160
 161 #define SYMBOL_HASH_SIZE 1024
 162
 163 struct symbol {
 164         struct symbol *next;
 165         struct module *module;
 166         unsigned int crc;
 167         int crc_valid;
 168         unsigned int weak:1;
 169         unsigned int vmlinux:1;    /* 1 if symbol is defined in vmlinux */
 170         unsigned int kernel:1;     /* 1 if symbol is from kernel
 171                                     *  (only for external modules) **/
 172         unsigned int preloaded:1;  /* 1 if symbol from Module.symvers, or crc */
 173         enum export  export;       /* Type of export */
 174         char name[0];
 175 };
 176
 177 static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
 178
 179 /* This is based on the hash agorithm from gdbm, via tdb */
 180 static inline unsigned int tdb_hash(const char *name)
 181 {
 182         unsigned value; /* Used to compute the hash value.  */
 183         unsigned   i;   /* Used to cycle through random values. */
 184
 185         /* Set the initial value from the key size. */
 186         for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
 187                 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
 188
 189         return (1103515243 * value + 12345);
 190 }
 191
 192 /**
 193  * Allocate a new symbols for use in the hash of exported symbols or
 194  * the list of unresolved symbols per module
 195  **/
 196 static struct symbol *alloc_symbol(const char *name, unsigned int weak,
 197                                    struct symbol *next)
 198 {
 199         struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
 200
 201         memset(s, 0, sizeof(*s));
 202         strcpy(s->name, name);
 203         s->weak = weak;
 204         s->next = next;
 205         return s;
 206 }
 207
 208 /* For the hash of exported symbols */
 209 static struct symbol *new_symbol(const char *name, struct module *module,
 210                                  enum export export)
 211 {
 212         unsigned int hash;
 213         struct symbol *new;
 214
 215         hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
 216         new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
 217         new->module = module;
 218         new->export = export;
 219         return new;
 220 }
 221
 222 static struct symbol *find_symbol(const char *name)
 223 {
 224         struct symbol *s;
 225
 226         /* For our purposes, .foo matches foo.  PPC64 needs this. */
 227         if (name[0] == '.')
 228                 name++;
 229
 230         for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
 231                 if (strcmp(s->name, name) == 0)
 232                         return s;
 233         }
 234         return NULL;
 235 }
 236
 237 static const struct {
 238         const char *str;
 239         enum export export;
 240 } export_list[] = {
 241         { .str = "EXPORT_SYMBOL",            .export = export_plain },
 242         { .str = "EXPORT_UNUSED_SYMBOL",     .export = export_unused },
 243         { .str = "EXPORT_SYMBOL_GPL",        .export = export_gpl },
 244         { .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
 245         { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
 246         { .str = "(unknown)",                .export = export_unknown },
 247 };
 248
 249
 250 static const char *export_str(enum export ex)
 251 {
 252         return export_list[ex].str;
 253 }
 254
 255 static enum export export_no(const char *s)
 256 {
 257         int i;
 258
 259         if (!s)
 260                 return export_unknown;
 261         for (i = 0; export_list[i].export != export_unknown; i++) {
 262                 if (strcmp(export_list[i].str, s) == 0)
 263                         return export_list[i].export;
 264         }
 265         return export_unknown;
 266 }
 267
 268 static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr)
 269 {
 270         return (void *)elf->hdr +
 271                 elf->sechdrs[elf->secindex_strings].sh_offset +
 272                 sechdr->sh_name;
 273 }
 274
 275 static const char *sec_name(struct elf_info *elf, int secindex)
 276 {
 277         return sech_name(elf, &elf->sechdrs[secindex]);
 278 }
 279
 280 #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)
 281
 282 static enum export export_from_secname(struct elf_info *elf, unsigned int sec)
 283 {
 284         const char *secname = sec_name(elf, sec);
 285
 286         if (strstarts(secname, "___ksymtab+"))
 287                 return export_plain;
 288         else if (strstarts(secname, "___ksymtab_unused+"))
 289                 return export_unused;
 290         else if (strstarts(secname, "___ksymtab_gpl+"))
 291                 return export_gpl;
 292         else if (strstarts(secname, "___ksymtab_unused_gpl+"))
 293                 return export_unused_gpl;
 294         else if (strstarts(secname, "___ksymtab_gpl_future+"))
 295                 return export_gpl_future;
 296         else
 297                 return export_unknown;
 298 }
 299
 300 static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
 301 {
 302         if (sec == elf->export_sec)
 303                 return export_plain;
 304         else if (sec == elf->export_unused_sec)
 305                 return export_unused;
 306         else if (sec == elf->export_gpl_sec)
 307                 return export_gpl;
 308         else if (sec == elf->export_unused_gpl_sec)
 309                 return export_unused_gpl;
 310         else if (sec == elf->export_gpl_future_sec)
 311                 return export_gpl_future;
 312         else
 313                 return export_unknown;
 314 }
 315
 316 /**
 317  * Add an exported symbol - it may have already been added without a
 318  * CRC, in this case just update the CRC
 319  **/
 320 static struct symbol *sym_add_exported(const char *name, struct module *mod,
 321                                        enum export export)
 322 {
 323         struct symbol *s = find_symbol(name);
 324
 325         if (!s) {
 326                 s = new_symbol(name, mod, export);
 327         } else {
 328                 if (!s->preloaded) {
 329                         warn("%s: '%s' exported twice. Previous export "
 330                              "was in %s%s\n", mod->name, name,
 331                              s->module->name,
 332                              is_vmlinux(s->module->name) ?"":".ko");
 333                 } else {
 334                         /* In case Module.symvers was out of date */
 335                         s->module = mod;
 336                 }
 337         }
 338         s->preloaded = 0;
 339         s->vmlinux   = is_vmlinux(mod->name);
 340         s->kernel    = 0;
 341         s->export    = export;
 342         return s;
 343 }
 344
 345 static void sym_update_crc(const char *name, struct module *mod,
 346                            unsigned int crc, enum export export)
 347 {
 348         struct symbol *s = find_symbol(name);
 349
 350         if (!s) {
 351                 s = new_symbol(name, mod, export);
 352                 /* Don't complain when we find it later. */
 353                 s->preloaded = 1;
 354         }
 355         s->crc = crc;
 356         s->crc_valid = 1;
 357 }
 358
 359 void *grab_file(const char *filename, unsigned long *size)
 360 {
 361         struct stat st;
 362         void *map = MAP_FAILED;
 363         int fd;
 364
 365         fd = open(filename, O_RDONLY);
 366         if (fd < 0)
 367                 return NULL;
 368         if (fstat(fd, &st))
 369                 goto failed;
 370
 371         *size = st.st_size;
 372         map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
 373
 374 failed:
 375         close(fd);
 376         if (map == MAP_FAILED)
 377                 return NULL;
 378         return map;
 379 }
 380
 381 /**
 382   * Return a copy of the next line in a mmap'ed file.
 383   * spaces in the beginning of the line is trimmed away.
 384   * Return a pointer to a static buffer.
 385   **/
 386 char *get_next_line(unsigned long *pos, void *file, unsigned long size)
 387 {
 388         static char line[4096];
 389         int skip = 1;
 390         size_t len = 0;
 391         signed char *p = (signed char *)file + *pos;
 392         char *s = line;
 393
 394         for (; *pos < size ; (*pos)++) {
 395                 if (skip && isspace(*p)) {
 396                         p++;
 397                         continue;
 398                 }
 399                 skip = 0;
 400                 if (*p != '\n' && (*pos < size)) {
 401                         len++;
 402                         *s++ = *p++;
 403                         if (len > 4095)
 404                                 break; /* Too long, stop */
 405                 } else {
 406                         /* End of string */
 407                         *s = '\0';
 408                         return line;
 409                 }
 410         }
 411         /* End of buffer */
 412         return NULL;
 413 }
 414
 415 void release_file(void *file, unsigned long size)
 416 {
 417         munmap(file, size);
 418 }
 419
 420 static int parse_elf(struct elf_info *info, const char *filename)
 421 {
 422         unsigned int i;
 423         Elf_Ehdr *hdr;
 424         Elf_Shdr *sechdrs;
 425         Elf_Sym  *sym;
 426         const char *secstrings;
 427         unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
 428
 429         hdr = grab_file(filename, &info->size);
 430         if (!hdr) {
 431                 if (ignore_missing_files) {
 432                         fprintf(stderr, "%s: %s (ignored)\n", filename,
 433                                 strerror(errno));
 434                         return 0;
 435                 }
 436                 perror(filename);
 437                 exit(1);
 438         }
 439         info->hdr = hdr;
 440         if (info->size < sizeof(*hdr)) {
 441                 /* file too small, assume this is an empty .o file */
 442                 return 0;
 443         }
 444         /* Is this a valid ELF file? */
 445         if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
 446             (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
 447             (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
 448             (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
 449                 /* Not an ELF file - silently ignore it */
 450                 return 0;
 451         }
 452         /* Fix endianness in ELF header */
 453         hdr->e_type      = TO_NATIVE(hdr->e_type);
 454         hdr->e_machine   = TO_NATIVE(hdr->e_machine);
 455         hdr->e_version   = TO_NATIVE(hdr->e_version);
 456         hdr->e_entry     = TO_NATIVE(hdr->e_entry);
 457         hdr->e_phoff     = TO_NATIVE(hdr->e_phoff);
 458         hdr->e_shoff     = TO_NATIVE(hdr->e_shoff);
 459         hdr->e_flags     = TO_NATIVE(hdr->e_flags);
 460         hdr->e_ehsize    = TO_NATIVE(hdr->e_ehsize);
 461         hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
 462         hdr->e_phnum     = TO_NATIVE(hdr->e_phnum);
 463         hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
 464         hdr->e_shnum     = TO_NATIVE(hdr->e_shnum);
 465         hdr->e_shstrndx  = TO_NATIVE(hdr->e_shstrndx);
 466         sechdrs = (void *)hdr + hdr->e_shoff;
 467         info->sechdrs = sechdrs;
 468
 469         /* Check if file offset is correct */
 470         if (hdr->e_shoff > info->size) {
 471                 fatal("section header offset=%lu in file '%s' is bigger than "
 472                       "filesize=%lu\n", (unsigned long)hdr->e_shoff,
 473                       filename, info->size);
 474                 return 0;
 475         }
 476
 477         if (hdr->e_shnum == SHN_UNDEF) {
 478                 /*
 479                  * There are more than 64k sections,
 480                  * read count from .sh_size.
 481                  */
 482                 info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
 483         }
 484         else {
 485                 info->num_sections = hdr->e_shnum;
 486         }
 487         if (hdr->e_shstrndx == SHN_XINDEX) {
 488                 info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
 489         }
 490         else {
 491                 info->secindex_strings = hdr->e_shstrndx;
 492         }
 493
 494         /* Fix endianness in section headers */
 495         for (i = 0; i < info->num_sections; i++) {
 496                 sechdrs[i].sh_name      = TO_NATIVE(sechdrs[i].sh_name);
 497                 sechdrs[i].sh_type      = TO_NATIVE(sechdrs[i].sh_type);
 498                 sechdrs[i].sh_flags     = TO_NATIVE(sechdrs[i].sh_flags);
 499                 sechdrs[i].sh_addr      = TO_NATIVE(sechdrs[i].sh_addr);
 500                 sechdrs[i].sh_offset    = TO_NATIVE(sechdrs[i].sh_offset);
 501                 sechdrs[i].sh_size      = TO_NATIVE(sechdrs[i].sh_size);
 502                 sechdrs[i].sh_link      = TO_NATIVE(sechdrs[i].sh_link);
 503                 sechdrs[i].sh_info      = TO_NATIVE(sechdrs[i].sh_info);
 504                 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
 505                 sechdrs[i].sh_entsize   = TO_NATIVE(sechdrs[i].sh_entsize);
 506         }
 507         /* Find symbol table. */
 508         secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
 509         for (i = 1; i < info->num_sections; i++) {
 510                 const char *secname;
 511                 int nobits = sechdrs[i].sh_type == SHT_NOBITS;
 512
 513                 if (!nobits && sechdrs[i].sh_offset > info->size) {
 514                         fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
 515                               "sizeof(*hrd)=%zu\n", filename,
 516                               (unsigned long)sechdrs[i].sh_offset,
 517                               sizeof(*hdr));
 518                         return 0;
 519                 }
 520                 secname = secstrings + sechdrs[i].sh_name;
 521                 if (strcmp(secname, ".modinfo") == 0) {
 522                         if (nobits)
 523                                 fatal("%s has NOBITS .modinfo\n", filename);
 524                         info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
 525                         info->modinfo_len = sechdrs[i].sh_size;
 526                 } else if (strcmp(secname, "__ksymtab") == 0)
 527                         info->export_sec = i;
 528                 else if (strcmp(secname, "__ksymtab_unused") == 0)
 529                         info->export_unused_sec = i;
 530                 else if (strcmp(secname, "__ksymtab_gpl") == 0)
 531                         info->export_gpl_sec = i;
 532                 else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
 533                         info->export_unused_gpl_sec = i;
 534                 else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
 535                         info->export_gpl_future_sec = i;
 536
 537                 if (sechdrs[i].sh_type == SHT_SYMTAB) {
 538                         unsigned int sh_link_idx;
 539                         symtab_idx = i;
 540                         info->symtab_start = (void *)hdr +
 541                             sechdrs[i].sh_offset;
 542                         info->symtab_stop  = (void *)hdr +
 543                             sechdrs[i].sh_offset + sechdrs[i].sh_size;
 544                         sh_link_idx = sechdrs[i].sh_link;
 545                         info->strtab       = (void *)hdr +
 546                             sechdrs[sh_link_idx].sh_offset;
 547                 }
 548
 549                 /* 32bit section no. table? ("more than 64k sections") */
 550                 if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
 551                         symtab_shndx_idx = i;
 552                         info->symtab_shndx_start = (void *)hdr +
 553                             sechdrs[i].sh_offset;
 554                         info->symtab_shndx_stop  = (void *)hdr +
 555                             sechdrs[i].sh_offset + sechdrs[i].sh_size;
 556                 }
 557         }
 558         if (!info->symtab_start)
 559                 fatal("%s has no symtab?\n", filename);
 560
 561         /* Fix endianness in symbols */
 562         for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
 563                 sym->st_shndx = TO_NATIVE(sym->st_shndx);
 564                 sym->st_name  = TO_NATIVE(sym->st_name);
 565                 sym->st_value = TO_NATIVE(sym->st_value);
 566                 sym->st_size  = TO_NATIVE(sym->st_size);
 567         }
 568
 569         if (symtab_shndx_idx != ~0U) {
 570                 Elf32_Word *p;
 571                 if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
 572                         fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
 573                               filename, sechdrs[symtab_shndx_idx].sh_link,
 574                               symtab_idx);
 575                 /* Fix endianness */
 576                 for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
 577                      p++)
 578                         *p = TO_NATIVE(*p);
 579         }
 580
 581         return 1;
 582 }
 583
 584 static void parse_elf_finish(struct elf_info *info)
 585 {
 586         release_file(info->hdr, info->size);
 587 }
 588
 589 static int ignore_undef_symbol(struct elf_info *info, const char *symname)
 590 {
 591         /* ignore __this_module, it will be resolved shortly */
 592         if (strcmp(symname, "__this_module") == 0)
 593                 return 1;
 594         /* ignore global offset table */
 595         if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
 596                 return 1;
 597         if (info->hdr->e_machine == EM_PPC)
 598                 /* Special register function linked on all modules during final link of .ko */
 599                 if (strstarts(symname, "_restgpr_") ||
 600                     strstarts(symname, "_savegpr_") ||
 601                     strstarts(symname, "_rest32gpr_") ||
 602                     strstarts(symname, "_save32gpr_") ||
 603                     strstarts(symname, "_restvr_") ||
 604                     strstarts(symname, "_savevr_"))
 605                         return 1;
 606         if (info->hdr->e_machine == EM_PPC64)
 607                 /* Special register function linked on all modules during final link of .ko */
 608                 if (strstarts(symname, "_restgpr0_") ||
 609                     strstarts(symname, "_savegpr0_") ||
 610                     strstarts(symname, "_restvr_") ||
 611                     strstarts(symname, "_savevr_") ||
 612                     strcmp(symname, ".TOC.") == 0)
 613                         return 1;
 614         /* Do not ignore this symbol */
 615         return 0;
 616 }
 617
 618 static void handle_modversions(struct module *mod, struct elf_info *info,
 619                                Elf_Sym *sym, const char *symname)
 620 {
 621         unsigned int crc;
 622         enum export export;
 623         bool is_crc = false;
 624
 625         if ((!is_vmlinux(mod->name) || mod->is_dot_o) &&
 626             strstarts(symname, "__ksymtab"))
 627                 export = export_from_secname(info, get_secindex(info, sym));
 628         else
 629                 export = export_from_sec(info, get_secindex(info, sym));
 630
 631         /* CRC'd symbol */
 632         if (strstarts(symname, "__crc_")) {
 633                 is_crc = true;
 634                 crc = (unsigned int) sym->st_value;
 635                 if (sym->st_shndx != SHN_UNDEF && sym->st_shndx != SHN_ABS) {
 636                         unsigned int *crcp;
 637
 638                         /* symbol points to the CRC in the ELF object */
 639                         crcp = (void *)info->hdr + sym->st_value +
 640                                info->sechdrs[sym->st_shndx].sh_offset -
 641                                (info->hdr->e_type != ET_REL ?
 642                                 info->sechdrs[sym->st_shndx].sh_addr : 0);
 643                         crc = *crcp;
 644                 }
 645                 sym_update_crc(symname + strlen("__crc_"), mod, crc,
 646                                 export);
 647         }
 648
 649         switch (sym->st_shndx) {
 650         case SHN_COMMON:
 651                 if (strstarts(symname, "__gnu_lto_")) {
 652                         /* Should warn here, but modpost runs before the linker */
 653                 } else
 654                         warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
 655                 break;
 656         case SHN_UNDEF:
 657                 /* undefined symbol */
 658                 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
 659                     ELF_ST_BIND(sym->st_info) != STB_WEAK)
 660                         break;
 661                 if (ignore_undef_symbol(info, symname))
 662                         break;
 663 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
 664 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
 665 /* add compatibility with older glibc */
 666 #ifndef STT_SPARC_REGISTER
 667 #define STT_SPARC_REGISTER STT_REGISTER
 668 #endif
 669                 if (info->hdr->e_machine == EM_SPARC ||
 670                     info->hdr->e_machine == EM_SPARCV9) {
 671                         /* Ignore register directives. */
 672                         if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
 673                                 break;
 674                         if (symname[0] == '.') {
 675                                 char *munged = NOFAIL(strdup(symname));
 676                                 munged[0] = '_';
 677                                 munged[1] = toupper(munged[1]);
 678                                 symname = munged;
 679                         }
 680                 }
 681 #endif
 682
 683                 if (is_crc) {
 684                         const char *e = is_vmlinux(mod->name) ?"":".ko";
 685                         warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n",
 686                              symname + strlen("__crc_"), mod->name, e);
 687                 }
 688                 mod->unres = alloc_symbol(symname,
 689                                           ELF_ST_BIND(sym->st_info) == STB_WEAK,
 690                                           mod->unres);
 691                 break;
 692         default:
 693                 /* All exported symbols */
 694                 if (strstarts(symname, "__ksymtab_")) {
 695                         sym_add_exported(symname + strlen("__ksymtab_"), mod,
 696                                         export);
 697                 }
 698                 if (strcmp(symname, "init_module") == 0)
 699                         mod->has_init = 1;
 700                 if (strcmp(symname, "cleanup_module") == 0)
 701                         mod->has_cleanup = 1;
 702                 break;
 703         }
 704 }
 705
 706 /**
 707  * Parse tag=value strings from .modinfo section
 708  **/
 709 static char *next_string(char *string, unsigned long *secsize)
 710 {
 711         /* Skip non-zero chars */
 712         while (string[0]) {
 713                 string++;
 714                 if ((*secsize)-- <= 1)
 715                         return NULL;
 716         }
 717
 718         /* Skip any zero padding. */
 719         while (!string[0]) {
 720                 string++;
 721                 if ((*secsize)-- <= 1)
 722                         return NULL;
 723         }
 724         return string;
 725 }
 726
 727 static char *get_next_modinfo(struct elf_info *info, const char *tag,
 728                               char *prev)
 729 {
 730         char *p;
 731         unsigned int taglen = strlen(tag);
 732         char *modinfo = info->modinfo;
 733         unsigned long size = info->modinfo_len;
 734
 735         if (prev) {
 736                 size -= prev - modinfo;
 737                 modinfo = next_string(prev, &size);
 738         }
 739
 740         for (p = modinfo; p; p = next_string(p, &size)) {
 741                 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
 742                         return p + taglen + 1;
 743         }
 744         return NULL;
 745 }
 746
 747 static char *get_modinfo(struct elf_info *info, const char *tag)
 748
 749 {
 750         return get_next_modinfo(info, tag, NULL);
 751 }
 752
 753 /**
 754  * Test if string s ends in string sub
 755  * return 0 if match
 756  **/
 757 static int strrcmp(const char *s, const char *sub)
 758 {
 759         int slen, sublen;
 760
 761         if (!s || !sub)
 762                 return 1;
 763
 764         slen = strlen(s);
 765         sublen = strlen(sub);
 766
 767         if ((slen == 0) || (sublen == 0))
 768                 return 1;
 769
 770         if (sublen > slen)
 771                 return 1;
 772
 773         return memcmp(s + slen - sublen, sub, sublen);
 774 }
 775
 776 static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
 777 {
 778         if (sym)
 779                 return elf->strtab + sym->st_name;
 780         else
 781                 return "(unknown)";
 782 }
 783
 784 /* The pattern is an array of simple patterns.
 785  * "foo" will match an exact string equal to "foo"
 786  * "*foo" will match a string that ends with "foo"
 787  * "foo*" will match a string that begins with "foo"
 788  * "*foo*" will match a string that contains "foo"
 789  */
 790 static int match(const char *sym, const char * const pat[])
 791 {
 792         const char *p;
 793         while (*pat) {
 794                 p = *pat++;
 795                 const char *endp = p + strlen(p) - 1;
 796
 797                 /* "*foo*" */
 798                 if (*p == '*' && *endp == '*') {
 799                         char *here, *bare = strndup(p + 1, strlen(p) - 2);
 800
 801                         here = strstr(sym, bare);
 802                         free(bare);
 803                         if (here != NULL)
 804                                 return 1;
 805                 }
 806                 /* "*foo" */
 807                 else if (*p == '*') {
 808                         if (strrcmp(sym, p + 1) == 0)
 809                                 return 1;
 810                 }
 811                 /* "foo*" */
 812                 else if (*endp == '*') {
 813                         if (strncmp(sym, p, strlen(p) - 1) == 0)
 814                                 return 1;
 815                 }
 816                 /* no wildcards */
 817                 else {
 818                         if (strcmp(p, sym) == 0)
 819                                 return 1;
 820                 }
 821         }
 822         /* no match */
 823         return 0;
 824 }
 825
 826 /* sections that we do not want to do full section mismatch check on */
 827 static const char *const section_white_list[] =
 828 {
 829         ".comment*",
 830         ".debug*",
 831         ".cranges",             /* sh64 */
 832         ".zdebug*",             /* Compressed debug sections. */
 833         ".GCC.command.line",    /* record-gcc-switches */
 834         ".mdebug*",        /* alpha, score, mips etc. */
 835         ".pdr",            /* alpha, score, mips etc. */
 836         ".stab*",
 837         ".note*",
 838         ".got*",
 839         ".toc*",
 840         ".xt.prop",                              /* xtensa */
 841         ".xt.lit",         /* xtensa */
 842         ".arcextmap*",                  /* arc */
 843         ".gnu.linkonce.arcext*",        /* arc : modules */
 844         ".cmem*",                       /* EZchip */
 845         ".fmt_slot*",                   /* EZchip */
 846         ".gnu.lto*",
 847         ".discard.*",
 848         NULL
 849 };
 850
 851 /*
 852  * This is used to find sections missing the SHF_ALLOC flag.
 853  * The cause of this is often a section specified in assembler
 854  * without "ax" / "aw".
 855  */
 856 static void check_section(const char *modname, struct elf_info *elf,
 857                           Elf_Shdr *sechdr)
 858 {
 859         const char *sec = sech_name(elf, sechdr);
 860
 861         if (sechdr->sh_type == SHT_PROGBITS &&
 862             !(sechdr->sh_flags & SHF_ALLOC) &&
 863             !match(sec, section_white_list)) {
 864                 warn("%s (%s): unexpected non-allocatable section.\n"
 865                      "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
 866                      "Note that for example <linux/init.h> contains\n"
 867                      "section definitions for use in .S files.\n\n",
 868                      modname, sec);
 869         }
 870 }
 871
 872
 873
 874 #define ALL_INIT_DATA_SECTIONS \
 875         ".init.setup", ".init.rodata", ".meminit.rodata", \
 876         ".init.data", ".meminit.data"
 877 #define ALL_EXIT_DATA_SECTIONS \
 878         ".exit.data", ".memexit.data"
 879
 880 #define ALL_INIT_TEXT_SECTIONS \
 881         ".init.text", ".meminit.text"
 882 #define ALL_EXIT_TEXT_SECTIONS \
 883         ".exit.text", ".memexit.text"
 884
 885 #define ALL_PCI_INIT_SECTIONS   \
 886         ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
 887         ".pci_fixup_enable", ".pci_fixup_resume", \
 888         ".pci_fixup_resume_early", ".pci_fixup_suspend"
 889
 890 #define ALL_XXXINIT_SECTIONS MEM_INIT_SECTIONS
 891 #define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS
 892
 893 #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
 894 #define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
 895
 896 #define DATA_SECTIONS ".data", ".data.rel"
 897 #define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \
 898                 ".kprobes.text", ".cpuidle.text"
 899 #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
 900                 ".fixup", ".entry.text", ".exception.text", ".text.*", \
 901                 ".coldtext"
 902
 903 #define INIT_SECTIONS      ".init.*"
 904 #define MEM_INIT_SECTIONS  ".meminit.*"
 905
 906 #define EXIT_SECTIONS      ".exit.*"
 907 #define MEM_EXIT_SECTIONS  ".memexit.*"
 908
 909 #define ALL_TEXT_SECTIONS  ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \
 910                 TEXT_SECTIONS, OTHER_TEXT_SECTIONS
 911
 912 /* init data sections */
 913 static const char *const init_data_sections[] =
 914         { ALL_INIT_DATA_SECTIONS, NULL };
 915
 916 /* all init sections */
 917 static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL };
 918
 919 /* All init and exit sections (code + data) */
 920 static const char *const init_exit_sections[] =
 921         {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
 922
 923 /* all text sections */
 924 static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL };
 925
 926 /* data section */
 927 static const char *const data_sections[] = { DATA_SECTIONS, NULL };
 928
 929
 930 /* symbols in .data that may refer to init/exit sections */
 931 #define DEFAULT_SYMBOL_WHITE_LIST                                       \
 932         "*driver",                                                      \
 933         "*_template", /* scsi uses *_template a lot */                  \
 934         "*_timer",    /* arm uses ops structures named _timer a lot */  \
 935         "*_sht",      /* scsi also used *_sht to some extent */         \
 936         "*_ops",                                                        \
 937         "*_probe",                                                      \
 938         "*_probe_one",                                                  \
 939         "*_console"
 940
 941 static const char *const head_sections[] = { ".head.text*", NULL };
 942 static const char *const linker_symbols[] =
 943         { "__init_begin", "_sinittext", "_einittext", NULL };
 944 static const char *const optim_symbols[] = { "*.constprop.*", NULL };
 945
 946 enum mismatch {
 947         TEXT_TO_ANY_INIT,
 948         DATA_TO_ANY_INIT,
 949         TEXT_TO_ANY_EXIT,
 950         DATA_TO_ANY_EXIT,
 951         XXXINIT_TO_SOME_INIT,
 952         XXXEXIT_TO_SOME_EXIT,
 953         ANY_INIT_TO_ANY_EXIT,
 954         ANY_EXIT_TO_ANY_INIT,
 955         EXPORT_TO_INIT_EXIT,
 956         EXTABLE_TO_NON_TEXT,
 957 };
 958
 959 /**
 960  * Describe how to match sections on different criterias:
 961  *
 962  * @fromsec: Array of sections to be matched.
 963  *
 964  * @bad_tosec: Relocations applied to a section in @fromsec to a section in
 965  * this array is forbidden (black-list).  Can be empty.
 966  *
 967  * @good_tosec: Relocations applied to a section in @fromsec must be
 968  * targetting sections in this array (white-list).  Can be empty.
 969  *
 970  * @mismatch: Type of mismatch.
 971  *
 972  * @symbol_white_list: Do not match a relocation to a symbol in this list
 973  * even if it is targetting a section in @bad_to_sec.
 974  *
 975  * @handler: Specific handler to call when a match is found.  If NULL,
 976  * default_mismatch_handler() will be called.
 977  *
 978  */
 979 struct sectioncheck {
 980         const char *fromsec[20];
 981         const char *bad_tosec[20];
 982         const char *good_tosec[20];
 983         enum mismatch mismatch;
 984         const char *symbol_white_list[20];
 985         void (*handler)(const char *modname, struct elf_info *elf,
 986                         const struct sectioncheck* const mismatch,
 987                         Elf_Rela *r, Elf_Sym *sym, const char *fromsec);
 988
 989 };
 990
 991 static void extable_mismatch_handler(const char *modname, struct elf_info *elf,
 992                                      const struct sectioncheck* const mismatch,
 993                                      Elf_Rela *r, Elf_Sym *sym,
 994                                      const char *fromsec);
 995
 996 static const struct sectioncheck sectioncheck[] = {
 997 /* Do not reference init/exit code/data from
 998  * normal code and data
 999  */
1000 {
1001         .fromsec = { TEXT_SECTIONS, NULL },
1002         .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1003         .mismatch = TEXT_TO_ANY_INIT,
1004         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1005 },
1006 {
1007         .fromsec = { DATA_SECTIONS, NULL },
1008         .bad_tosec = { ALL_XXXINIT_SECTIONS, NULL },
1009         .mismatch = DATA_TO_ANY_INIT,
1010         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1011 },
1012 {
1013         .fromsec = { DATA_SECTIONS, NULL },
1014         .bad_tosec = { INIT_SECTIONS, NULL },
1015         .mismatch = DATA_TO_ANY_INIT,
1016         .symbol_white_list = {
1017                 "*_template", "*_timer", "*_sht", "*_ops",
1018                 "*_probe", "*_probe_one", "*_console", NULL
1019         },
1020 },
1021 {
1022         .fromsec = { TEXT_SECTIONS, NULL },
1023         .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1024         .mismatch = TEXT_TO_ANY_EXIT,
1025         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1026 },
1027 {
1028         .fromsec = { DATA_SECTIONS, NULL },
1029         .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1030         .mismatch = DATA_TO_ANY_EXIT,
1031         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1032 },
1033 /* Do not reference init code/data from meminit code/data */
1034 {
1035         .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
1036         .bad_tosec = { INIT_SECTIONS, NULL },
1037         .mismatch = XXXINIT_TO_SOME_INIT,
1038         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1039 },
1040 /* Do not reference exit code/data from memexit code/data */
1041 {
1042         .fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
1043         .bad_tosec = { EXIT_SECTIONS, NULL },
1044         .mismatch = XXXEXIT_TO_SOME_EXIT,
1045         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1046 },
1047 /* Do not use exit code/data from init code */
1048 {
1049         .fromsec = { ALL_INIT_SECTIONS, NULL },
1050         .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1051         .mismatch = ANY_INIT_TO_ANY_EXIT,
1052         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1053 },
1054 /* Do not use init code/data from exit code */
1055 {
1056         .fromsec = { ALL_EXIT_SECTIONS, NULL },
1057         .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1058         .mismatch = ANY_EXIT_TO_ANY_INIT,
1059         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1060 },
1061 {
1062         .fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
1063         .bad_tosec = { INIT_SECTIONS, NULL },
1064         .mismatch = ANY_INIT_TO_ANY_EXIT,
1065         .symbol_white_list = { NULL },
1066 },
1067 /* Do not export init/exit functions or data */
1068 {
1069         .fromsec = { "__ksymtab*", NULL },
1070         .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
1071         .mismatch = EXPORT_TO_INIT_EXIT,
1072         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1073 },
1074 {
1075         .fromsec = { "__ex_table", NULL },
1076         /* If you're adding any new black-listed sections in here, consider
1077          * adding a special 'printer' for them in scripts/check_extable.
1078          */
1079         .bad_tosec = { ".altinstr_replacement", NULL },
1080         .good_tosec = {ALL_TEXT_SECTIONS , NULL},
1081         .mismatch = EXTABLE_TO_NON_TEXT,
1082         .handler = extable_mismatch_handler,
1083 }
1084 };
1085
1086 static const struct sectioncheck *section_mismatch(
1087                 const char *fromsec, const char *tosec)
1088 {
1089         int i;
1090         int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
1091         const struct sectioncheck *check = &sectioncheck[0];
1092
1093         /*
1094          * The target section could be the SHT_NUL section when we're
1095          * handling relocations to un-resolved symbols, trying to match it
1096          * doesn't make much sense and causes build failures on parisc
1097          * architectures.
1098          */
1099         if (*tosec == '\0')
1100                 return NULL;
1101
1102         for (i = 0; i < elems; i++) {
1103                 if (match(fromsec, check->fromsec)) {
1104                         if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
1105                                 return check;
1106                         if (check->good_tosec[0] && !match(tosec, check->good_tosec))
1107                                 return check;
1108                 }
1109                 check++;
1110         }
1111         return NULL;
1112 }
1113
1114 /**
1115  * Whitelist to allow certain references to pass with no warning.
1116  *
1117  * Pattern 1:
1118  *   If a module parameter is declared __initdata and permissions=0
1119  *   then this is legal despite the warning generated.
1120  *   We cannot see value of permissions here, so just ignore
1121  *   this pattern.
1122  *   The pattern is identified by:
1123  *   tosec   = .init.data
1124  *   fromsec = .data*
1125  *   atsym   =__param*
1126  *
1127  * Pattern 1a:
1128  *   module_param_call() ops can refer to __init set function if permissions=0
1129  *   The pattern is identified by:
1130  *   tosec   = .init.text
1131  *   fromsec = .data*
1132  *   atsym   = __param_ops_*
1133  *
1134  * Pattern 2:
1135  *   Many drivers utilise a *driver container with references to
1136  *   add, remove, probe functions etc.
1137  *   the pattern is identified by:
1138  *   tosec   = init or exit section
1139  *   fromsec = data section
1140  *   atsym = *driver, *_template, *_sht, *_ops, *_probe,
1141  *           *probe_one, *_console, *_timer
1142  *
1143  * Pattern 3:
1144  *   Whitelist all references from .head.text to any init section
1145  *
1146  * Pattern 4:
1147  *   Some symbols belong to init section but still it is ok to reference
1148  *   these from non-init sections as these symbols don't have any memory
1149  *   allocated for them and symbol address and value are same. So even
1150  *   if init section is freed, its ok to reference those symbols.
1151  *   For ex. symbols marking the init section boundaries.
1152  *   This pattern is identified by
1153  *   refsymname = __init_begin, _sinittext, _einittext
1154  *
1155  * Pattern 5:
1156  *   GCC may optimize static inlines when fed constant arg(s) resulting
1157  *   in functions like cpumask_empty() -- generating an associated symbol
1158  *   cpumask_empty.constprop.3 that appears in the audit.  If the const that
1159  *   is passed in comes from __init, like say nmi_ipi_mask, we get a
1160  *   meaningless section warning.  May need to add isra symbols too...
1161  *   This pattern is identified by
1162  *   tosec   = init section
1163  *   fromsec = text section
1164  *   refsymname = *.constprop.*
1165  *
1166  **/
1167 static int secref_whitelist(const struct sectioncheck *mismatch,
1168                             const char *fromsec, const char *fromsym,
1169                             const char *tosec, const char *tosym)
1170 {
1171         /* Check for pattern 1 */
1172         if (match(tosec, init_data_sections) &&
1173             match(fromsec, data_sections) &&
1174             strstarts(fromsym, "__param"))
1175                 return 0;
1176
1177         /* Check for pattern 1a */
1178         if (strcmp(tosec, ".init.text") == 0 &&
1179             match(fromsec, data_sections) &&
1180             strstarts(fromsym, "__param_ops_"))
1181                 return 0;
1182
1183         /* Check for pattern 2 */
1184         if (match(tosec, init_exit_sections) &&
1185             match(fromsec, data_sections) &&
1186             match(fromsym, mismatch->symbol_white_list))
1187                 return 0;
1188
1189         /* Check for pattern 3 */
1190         if (match(fromsec, head_sections) &&
1191             match(tosec, init_sections))
1192                 return 0;
1193
1194         /* Check for pattern 4 */
1195         if (match(tosym, linker_symbols))
1196                 return 0;
1197
1198         /* Check for pattern 5 */
1199         if (match(fromsec, text_sections) &&
1200             match(tosec, init_sections) &&
1201             match(fromsym, optim_symbols))
1202                 return 0;
1203
1204         return 1;
1205 }
1206
1207 /**
1208  * Find symbol based on relocation record info.
1209  * In some cases the symbol supplied is a valid symbol so
1210  * return refsym. If st_name != 0 we assume this is a valid symbol.
1211  * In other cases the symbol needs to be looked up in the symbol table
1212  * based on section and address.
1213  *  **/
1214 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
1215                                 Elf_Sym *relsym)
1216 {
1217         Elf_Sym *sym;
1218         Elf_Sym *near = NULL;
1219         Elf64_Sword distance = 20;
1220         Elf64_Sword d;
1221         unsigned int relsym_secindex;
1222
1223         if (relsym->st_name != 0)
1224                 return relsym;
1225
1226         relsym_secindex = get_secindex(elf, relsym);
1227         for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1228                 if (get_secindex(elf, sym) != relsym_secindex)
1229                         continue;
1230                 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
1231                         continue;
1232                 if (sym->st_value == addr)
1233                         return sym;
1234                 /* Find a symbol nearby - addr are maybe negative */
1235                 d = sym->st_value - addr;
1236                 if (d < 0)
1237                         d = addr - sym->st_value;
1238                 if (d < distance) {
1239                         distance = d;
1240                         near = sym;
1241                 }
1242         }
1243         /* We need a close match */
1244         if (distance < 20)
1245                 return near;
1246         else
1247                 return NULL;
1248 }
1249
1250 static inline int is_arm_mapping_symbol(const char *str)
1251 {
1252         return str[0] == '$' && strchr("axtd", str[1])
1253                && (str[2] == '\0' || str[2] == '.');
1254 }
1255
1256 /*
1257  * If there's no name there, ignore it; likewise, ignore it if it's
1258  * one of the magic symbols emitted used by current ARM tools.
1259  *
1260  * Otherwise if find_symbols_between() returns those symbols, they'll
1261  * fail the whitelist tests and cause lots of false alarms ... fixable
1262  * only by merging __exit and __init sections into __text, bloating
1263  * the kernel (which is especially evil on embedded platforms).
1264  */
1265 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1266 {
1267         const char *name = elf->strtab + sym->st_name;
1268
1269         if (!name || !strlen(name))
1270                 return 0;
1271         return !is_arm_mapping_symbol(name);
1272 }
1273
1274 /*
1275  * Find symbols before or equal addr and after addr - in the section sec.
1276  * If we find two symbols with equal offset prefer one with a valid name.
1277  * The ELF format may have a better way to detect what type of symbol
1278  * it is, but this works for now.
1279  **/
1280 static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1281                                  const char *sec)
1282 {
1283         Elf_Sym *sym;
1284         Elf_Sym *near = NULL;
1285         Elf_Addr distance = ~0;
1286
1287         for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1288                 const char *symsec;
1289
1290                 if (is_shndx_special(sym->st_shndx))
1291                         continue;
1292                 symsec = sec_name(elf, get_secindex(elf, sym));
1293                 if (strcmp(symsec, sec) != 0)
1294                         continue;
1295                 if (!is_valid_name(elf, sym))
1296                         continue;
1297                 if (sym->st_value <= addr) {
1298                         if ((addr - sym->st_value) < distance) {
1299                                 distance = addr - sym->st_value;
1300                                 near = sym;
1301                         } else if ((addr - sym->st_value) == distance) {
1302                                 near = sym;
1303                         }
1304                 }
1305         }
1306         return near;
1307 }
1308
1309 /*
1310  * Convert a section name to the function/data attribute
1311  * .init.text => __init
1312  * .memexitconst => __memconst
1313  * etc.
1314  *
1315  * The memory of returned value has been allocated on a heap. The user of this
1316  * method should free it after usage.
1317 */
1318 static char *sec2annotation(const char *s)
1319 {
1320         if (match(s, init_exit_sections)) {
1321                 char *p = NOFAIL(malloc(20));
1322                 char *r = p;
1323
1324                 *p++ = '_';
1325                 *p++ = '_';
1326                 if (*s == '.')
1327                         s++;
1328                 while (*s && *s != '.')
1329                         *p++ = *s++;
1330                 *p = '\0';
1331                 if (*s == '.')
1332                         s++;
1333                 if (strstr(s, "rodata") != NULL)
1334                         strcat(p, "const ");
1335                 else if (strstr(s, "data") != NULL)
1336                         strcat(p, "data ");
1337                 else
1338                         strcat(p, " ");
1339                 return r;
1340         } else {
1341                 return NOFAIL(strdup(""));
1342         }
1343 }
1344
1345 static int is_function(Elf_Sym *sym)
1346 {
1347         if (sym)
1348                 return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1349         else
1350                 return -1;
1351 }
1352
1353 static void print_section_list(const char * const list[20])
1354 {
1355         const char *const *s = list;
1356
1357         while (*s) {
1358                 fprintf(stderr, "%s", *s);
1359                 s++;
1360                 if (*s)
1361                         fprintf(stderr, ", ");
1362         }
1363         fprintf(stderr, "\n");
1364 }
1365
1366 static inline void get_pretty_name(int is_func, const char** name, const char** name_p)
1367 {
1368         switch (is_func) {
1369         case 0: *name = "variable"; *name_p = ""; break;
1370         case 1: *name = "function"; *name_p = "()"; break;
1371         default: *name = "(unknown reference)"; *name_p = ""; break;
1372         }
1373 }
1374
1375 /*
1376  * Print a warning about a section mismatch.
1377  * Try to find symbols near it so user can find it.
1378  * Check whitelist before warning - it may be a false positive.
1379  */
1380 static void report_sec_mismatch(const char *modname,
1381                                 const struct sectioncheck *mismatch,
1382                                 const char *fromsec,
1383                                 unsigned long long fromaddr,
1384                                 const char *fromsym,
1385                                 int from_is_func,
1386                                 const char *tosec, const char *tosym,
1387                                 int to_is_func)
1388 {
1389         const char *from, *from_p;
1390         const char *to, *to_p;
1391         char *prl_from;
1392         char *prl_to;
1393
1394         sec_mismatch_count++;
1395         if (!sec_mismatch_verbose)
1396                 return;
1397
1398         get_pretty_name(from_is_func, &from, &from_p);
1399         get_pretty_name(to_is_func, &to, &to_p);
1400
1401         warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1402              "to the %s %s:%s%s\n",
1403              modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1404              tosym, to_p);
1405
1406         switch (mismatch->mismatch) {
1407         case TEXT_TO_ANY_INIT:
1408                 prl_from = sec2annotation(fromsec);
1409                 prl_to = sec2annotation(tosec);
1410                 fprintf(stderr,
1411                 "The function %s%s() references\n"
1412                 "the %s %s%s%s.\n"
1413                 "This is often because %s lacks a %s\n"
1414                 "annotation or the annotation of %s is wrong.\n",
1415                 prl_from, fromsym,
1416                 to, prl_to, tosym, to_p,
1417                 fromsym, prl_to, tosym);
1418                 free(prl_from);
1419                 free(prl_to);
1420                 break;
1421         case DATA_TO_ANY_INIT: {
1422                 prl_to = sec2annotation(tosec);
1423                 fprintf(stderr,
1424                 "The variable %s references\n"
1425                 "the %s %s%s%s\n"
1426                 "If the reference is valid then annotate the\n"
1427                 "variable with __init* or __refdata (see linux/init.h) "
1428                 "or name the variable:\n",
1429                 fromsym, to, prl_to, tosym, to_p);
1430                 print_section_list(mismatch->symbol_white_list);
1431                 free(prl_to);
1432                 break;
1433         }
1434         case TEXT_TO_ANY_EXIT:
1435                 prl_to = sec2annotation(tosec);
1436                 fprintf(stderr,
1437                 "The function %s() references a %s in an exit section.\n"
1438                 "Often the %s %s%s has valid usage outside the exit section\n"
1439                 "and the fix is to remove the %sannotation of %s.\n",
1440                 fromsym, to, to, tosym, to_p, prl_to, tosym);
1441                 free(prl_to);
1442                 break;
1443         case DATA_TO_ANY_EXIT: {
1444                 prl_to = sec2annotation(tosec);
1445                 fprintf(stderr,
1446                 "The variable %s references\n"
1447                 "the %s %s%s%s\n"
1448                 "If the reference is valid then annotate the\n"
1449                 "variable with __exit* (see linux/init.h) or "
1450                 "name the variable:\n",
1451                 fromsym, to, prl_to, tosym, to_p);
1452                 print_section_list(mismatch->symbol_white_list);
1453                 free(prl_to);
1454                 break;
1455         }
1456         case XXXINIT_TO_SOME_INIT:
1457         case XXXEXIT_TO_SOME_EXIT:
1458                 prl_from = sec2annotation(fromsec);
1459                 prl_to = sec2annotation(tosec);
1460                 fprintf(stderr,
1461                 "The %s %s%s%s references\n"
1462                 "a %s %s%s%s.\n"
1463                 "If %s is only used by %s then\n"
1464                 "annotate %s with a matching annotation.\n",
1465                 from, prl_from, fromsym, from_p,
1466                 to, prl_to, tosym, to_p,
1467                 tosym, fromsym, tosym);
1468                 free(prl_from);
1469                 free(prl_to);
1470                 break;
1471         case ANY_INIT_TO_ANY_EXIT:
1472                 prl_from = sec2annotation(fromsec);
1473                 prl_to = sec2annotation(tosec);
1474                 fprintf(stderr,
1475                 "The %s %s%s%s references\n"
1476                 "a %s %s%s%s.\n"
1477                 "This is often seen when error handling "
1478                 "in the init function\n"
1479                 "uses functionality in the exit path.\n"
1480                 "The fix is often to remove the %sannotation of\n"
1481                 "%s%s so it may be used outside an exit section.\n",
1482                 from, prl_from, fromsym, from_p,
1483                 to, prl_to, tosym, to_p,
1484                 prl_to, tosym, to_p);
1485                 free(prl_from);
1486                 free(prl_to);
1487                 break;
1488         case ANY_EXIT_TO_ANY_INIT:
1489                 prl_from = sec2annotation(fromsec);
1490                 prl_to = sec2annotation(tosec);
1491                 fprintf(stderr,
1492                 "The %s %s%s%s references\n"
1493                 "a %s %s%s%s.\n"
1494                 "This is often seen when error handling "
1495                 "in the exit function\n"
1496                 "uses functionality in the init path.\n"
1497                 "The fix is often to remove the %sannotation of\n"
1498                 "%s%s so it may be used outside an init section.\n",
1499                 from, prl_from, fromsym, from_p,
1500                 to, prl_to, tosym, to_p,
1501                 prl_to, tosym, to_p);
1502                 free(prl_from);
1503                 free(prl_to);
1504                 break;
1505         case EXPORT_TO_INIT_EXIT:
1506                 prl_to = sec2annotation(tosec);
1507                 fprintf(stderr,
1508                 "The symbol %s is exported and annotated %s\n"
1509                 "Fix this by removing the %sannotation of %s "
1510                 "or drop the export.\n",
1511                 tosym, prl_to, prl_to, tosym);
1512                 free(prl_to);
1513                 break;
1514         case EXTABLE_TO_NON_TEXT:
1515                 fatal("There's a special handler for this mismatch type, "
1516                       "we should never get here.");
1517                 break;
1518         }
1519         fprintf(stderr, "\n");
1520 }
1521
1522 static void default_mismatch_handler(const char *modname, struct elf_info *elf,
1523                                      const struct sectioncheck* const mismatch,
1524                                      Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1525 {
1526         const char *tosec;
1527         Elf_Sym *to;
1528         Elf_Sym *from;
1529         const char *tosym;
1530         const char *fromsym;
1531
1532         from = find_elf_symbol2(elf, r->r_offset, fromsec);
1533         fromsym = sym_name(elf, from);
1534
1535         if (strstarts(fromsym, "reference___initcall"))
1536                 return;
1537
1538         tosec = sec_name(elf, get_secindex(elf, sym));
1539         to = find_elf_symbol(elf, r->r_addend, sym);
1540         tosym = sym_name(elf, to);
1541
1542         /* check whitelist - we may ignore it */
1543         if (secref_whitelist(mismatch,
1544                              fromsec, fromsym, tosec, tosym)) {
1545                 report_sec_mismatch(modname, mismatch,
1546                                     fromsec, r->r_offset, fromsym,
1547                                     is_function(from), tosec, tosym,
1548                                     is_function(to));
1549         }
1550 }
1551
1552 static int is_executable_section(struct elf_info* elf, unsigned int section_index)
1553 {
1554         if (section_index > elf->num_sections)
1555                 fatal("section_index is outside elf->num_sections!\n");
1556
1557         return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR);
1558 }
1559
1560 /*
1561  * We rely on a gross hack in section_rel[a]() calling find_extable_entry_size()
1562  * to know the sizeof(struct exception_table_entry) for the target architecture.
1563  */
1564 static unsigned int extable_entry_size = 0;
1565 static void find_extable_entry_size(const char* const sec, const Elf_Rela* r)
1566 {
1567         /*
1568          * If we're currently checking the second relocation within __ex_table,
1569          * that relocation offset tells us the offsetof(struct
1570          * exception_table_entry, fixup) which is equal to sizeof(struct
1571          * exception_table_entry) divided by two.  We use that to our advantage
1572          * since there's no portable way to get that size as every architecture
1573          * seems to go with different sized types.  Not pretty but better than
1574          * hard-coding the size for every architecture..
1575          */
1576         if (!extable_entry_size)
1577                 extable_entry_size = r->r_offset * 2;
1578 }
1579
1580 static inline bool is_extable_fault_address(Elf_Rela *r)
1581 {
1582         /*
1583          * extable_entry_size is only discovered after we've handled the
1584          * _second_ relocation in __ex_table, so only abort when we're not
1585          * handling the first reloc and extable_entry_size is zero.
1586          */
1587         if (r->r_offset && extable_entry_size == 0)
1588                 fatal("extable_entry size hasn't been discovered!\n");
1589
1590         return ((r->r_offset == 0) ||
1591                 (r->r_offset % extable_entry_size == 0));
1592 }
1593
1594 #define is_second_extable_reloc(Start, Cur, Sec)                        \
1595         (((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0))
1596
1597 static void report_extable_warnings(const char* modname, struct elf_info* elf,
1598                                     const struct sectioncheck* const mismatch,
1599                                     Elf_Rela* r, Elf_Sym* sym,
1600                                     const char* fromsec, const char* tosec)
1601 {
1602         Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec);
1603         const char* fromsym_name = sym_name(elf, fromsym);
1604         Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym);
1605         const char* tosym_name = sym_name(elf, tosym);
1606         const char* from_pretty_name;
1607         const char* from_pretty_name_p;
1608         const char* to_pretty_name;
1609         const char* to_pretty_name_p;
1610
1611         get_pretty_name(is_function(fromsym),
1612                         &from_pretty_name, &from_pretty_name_p);
1613         get_pretty_name(is_function(tosym),
1614                         &to_pretty_name, &to_pretty_name_p);
1615
1616         warn("%s(%s+0x%lx): Section mismatch in reference"
1617              " from the %s %s%s to the %s %s:%s%s\n",
1618              modname, fromsec, (long)r->r_offset, from_pretty_name,
1619              fromsym_name, from_pretty_name_p,
1620              to_pretty_name, tosec, tosym_name, to_pretty_name_p);
1621
1622         if (!match(tosec, mismatch->bad_tosec) &&
1623             is_executable_section(elf, get_secindex(elf, sym)))
1624                 fprintf(stderr,
1625                         "The relocation at %s+0x%lx references\n"
1626                         "section \"%s\" which is not in the list of\n"
1627                         "authorized sections.  If you're adding a new section\n"
1628                         "and/or if this reference is valid, add \"%s\" to the\n"
1629                         "list of authorized sections to jump to on fault.\n"
1630                         "This can be achieved by adding \"%s\" to \n"
1631                         "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
1632                         fromsec, (long)r->r_offset, tosec, tosec, tosec);
1633 }
1634
1635 static void extable_mismatch_handler(const char* modname, struct elf_info *elf,
1636                                      const struct sectioncheck* const mismatch,
1637                                      Elf_Rela* r, Elf_Sym* sym,
1638                                      const char *fromsec)
1639 {
1640         const char* tosec = sec_name(elf, get_secindex(elf, sym));
1641
1642         sec_mismatch_count++;
1643
1644         if (sec_mismatch_verbose)
1645                 report_extable_warnings(modname, elf, mismatch, r, sym,
1646                                         fromsec, tosec);
1647
1648         if (match(tosec, mismatch->bad_tosec))
1649                 fatal("The relocation at %s+0x%lx references\n"
1650                       "section \"%s\" which is black-listed.\n"
1651                       "Something is seriously wrong and should be fixed.\n"
1652                       "You might get more information about where this is\n"
1653                       "coming from by using scripts/check_extable.sh %s\n",
1654                       fromsec, (long)r->r_offset, tosec, modname);
1655         else if (!is_executable_section(elf, get_secindex(elf, sym))) {
1656                 if (is_extable_fault_address(r))
1657                         fatal("The relocation at %s+0x%lx references\n"
1658                               "section \"%s\" which is not executable, IOW\n"
1659                               "it is not possible for the kernel to fault\n"
1660                               "at that address.  Something is seriously wrong\n"
1661                               "and should be fixed.\n",
1662                               fromsec, (long)r->r_offset, tosec);
1663                 else
1664                         fatal("The relocation at %s+0x%lx references\n"
1665                               "section \"%s\" which is not executable, IOW\n"
1666                               "the kernel will fault if it ever tries to\n"
1667                               "jump to it.  Something is seriously wrong\n"
1668                               "and should be fixed.\n",
1669                               fromsec, (long)r->r_offset, tosec);
1670         }
1671 }
1672
1673 static void check_section_mismatch(const char *modname, struct elf_info *elf,
1674                                    Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1675 {
1676         const char *tosec = sec_name(elf, get_secindex(elf, sym));
1677         const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec);
1678
1679         if (mismatch) {
1680                 if (mismatch->handler)
1681                         mismatch->handler(modname, elf,  mismatch,
1682                                           r, sym, fromsec);
1683                 else
1684                         default_mismatch_handler(modname, elf, mismatch,
1685                                                  r, sym, fromsec);
1686         }
1687 }
1688
1689 static unsigned int *reloc_location(struct elf_info *elf,
1690                                     Elf_Shdr *sechdr, Elf_Rela *r)
1691 {
1692         Elf_Shdr *sechdrs = elf->sechdrs;
1693         int section = sechdr->sh_info;
1694
1695         return (void *)elf->hdr + sechdrs[section].sh_offset +
1696                 r->r_offset;
1697 }
1698
1699 static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1700 {
1701         unsigned int r_typ = ELF_R_TYPE(r->r_info);
1702         unsigned int *location = reloc_location(elf, sechdr, r);
1703
1704         switch (r_typ) {
1705         case R_386_32:
1706                 r->r_addend = TO_NATIVE(*location);
1707                 break;
1708         case R_386_PC32:
1709                 r->r_addend = TO_NATIVE(*location) + 4;
1710                 /* For CONFIG_RELOCATABLE=y */
1711                 if (elf->hdr->e_type == ET_EXEC)
1712                         r->r_addend += r->r_offset;
1713                 break;
1714         }
1715         return 0;
1716 }
1717
1718 #ifndef R_ARM_CALL
1719 #define R_ARM_CALL      28
1720 #endif
1721 #ifndef R_ARM_JUMP24
1722 #define R_ARM_JUMP24    29
1723 #endif
1724
1725 #ifndef R_ARM_THM_CALL
1726 #define R_ARM_THM_CALL          10
1727 #endif
1728 #ifndef R_ARM_THM_JUMP24
1729 #define R_ARM_THM_JUMP24        30
1730 #endif
1731 #ifndef R_ARM_THM_JUMP19
1732 #define R_ARM_THM_JUMP19        51
1733 #endif
1734
1735 static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1736 {
1737         unsigned int r_typ = ELF_R_TYPE(r->r_info);
1738
1739         switch (r_typ) {
1740         case R_ARM_ABS32:
1741                 /* From ARM ABI: (S + A) | T */
1742                 r->r_addend = (int)(long)
1743                               (elf->symtab_start + ELF_R_SYM(r->r_info));
1744                 break;
1745         case R_ARM_PC24:
1746         case R_ARM_CALL:
1747         case R_ARM_JUMP24:
1748         case R_ARM_THM_CALL:
1749         case R_ARM_THM_JUMP24:
1750         case R_ARM_THM_JUMP19:
1751                 /* From ARM ABI: ((S + A) | T) - P */
1752                 r->r_addend = (int)(long)(elf->hdr +
1753                               sechdr->sh_offset +
1754                               (r->r_offset - sechdr->sh_addr));
1755                 break;
1756         default:
1757                 return 1;
1758         }
1759         return 0;
1760 }
1761
1762 static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1763 {
1764         unsigned int r_typ = ELF_R_TYPE(r->r_info);
1765         unsigned int *location = reloc_location(elf, sechdr, r);
1766         unsigned int inst;
1767
1768         if (r_typ == R_MIPS_HI16)
1769                 return 1;       /* skip this */
1770         inst = TO_NATIVE(*location);
1771         switch (r_typ) {
1772         case R_MIPS_LO16:
1773                 r->r_addend = inst & 0xffff;
1774                 break;
1775         case R_MIPS_26:
1776                 r->r_addend = (inst & 0x03ffffff) << 2;
1777                 break;
1778         case R_MIPS_32:
1779                 r->r_addend = inst;
1780                 break;
1781         }
1782         return 0;
1783 }
1784
1785 static void section_rela(const char *modname, struct elf_info *elf,
1786                          Elf_Shdr *sechdr)
1787 {
1788         Elf_Sym  *sym;
1789         Elf_Rela *rela;
1790         Elf_Rela r;
1791         unsigned int r_sym;
1792         const char *fromsec;
1793
1794         Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1795         Elf_Rela *stop  = (void *)start + sechdr->sh_size;
1796
1797         fromsec = sech_name(elf, sechdr);
1798         fromsec += strlen(".rela");
1799         /* if from section (name) is know good then skip it */
1800         if (match(fromsec, section_white_list))
1801                 return;
1802
1803         for (rela = start; rela < stop; rela++) {
1804                 r.r_offset = TO_NATIVE(rela->r_offset);
1805 #if KERNEL_ELFCLASS == ELFCLASS64
1806                 if (elf->hdr->e_machine == EM_MIPS) {
1807                         unsigned int r_typ;
1808                         r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1809                         r_sym = TO_NATIVE(r_sym);
1810                         r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1811                         r.r_info = ELF64_R_INFO(r_sym, r_typ);
1812                 } else {
1813                         r.r_info = TO_NATIVE(rela->r_info);
1814                         r_sym = ELF_R_SYM(r.r_info);
1815                 }
1816 #else
1817                 r.r_info = TO_NATIVE(rela->r_info);
1818                 r_sym = ELF_R_SYM(r.r_info);
1819 #endif
1820                 r.r_addend = TO_NATIVE(rela->r_addend);
1821                 sym = elf->symtab_start + r_sym;
1822                 /* Skip special sections */
1823                 if (is_shndx_special(sym->st_shndx))
1824                         continue;
1825                 if (is_second_extable_reloc(start, rela, fromsec))
1826                         find_extable_entry_size(fromsec, &r);
1827                 check_section_mismatch(modname, elf, &r, sym, fromsec);
1828         }
1829 }
1830
1831 static void section_rel(const char *modname, struct elf_info *elf,
1832                         Elf_Shdr *sechdr)
1833 {
1834         Elf_Sym *sym;
1835         Elf_Rel *rel;
1836         Elf_Rela r;
1837         unsigned int r_sym;
1838         const char *fromsec;
1839
1840         Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1841         Elf_Rel *stop  = (void *)start + sechdr->sh_size;
1842
1843         fromsec = sech_name(elf, sechdr);
1844         fromsec += strlen(".rel");
1845         /* if from section (name) is know good then skip it */
1846         if (match(fromsec, section_white_list))
1847                 return;
1848
1849         for (rel = start; rel < stop; rel++) {
1850                 r.r_offset = TO_NATIVE(rel->r_offset);
1851 #if KERNEL_ELFCLASS == ELFCLASS64
1852                 if (elf->hdr->e_machine == EM_MIPS) {
1853                         unsigned int r_typ;
1854                         r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1855                         r_sym = TO_NATIVE(r_sym);
1856                         r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1857                         r.r_info = ELF64_R_INFO(r_sym, r_typ);
1858                 } else {
1859                         r.r_info = TO_NATIVE(rel->r_info);
1860                         r_sym = ELF_R_SYM(r.r_info);
1861                 }
1862 #else
1863                 r.r_info = TO_NATIVE(rel->r_info);
1864                 r_sym = ELF_R_SYM(r.r_info);
1865 #endif
1866                 r.r_addend = 0;
1867                 switch (elf->hdr->e_machine) {
1868                 case EM_386:
1869                         if (addend_386_rel(elf, sechdr, &r))
1870                                 continue;
1871                         break;
1872                 case EM_ARM:
1873                         if (addend_arm_rel(elf, sechdr, &r))
1874                                 continue;
1875                         break;
1876                 case EM_MIPS:
1877                         if (addend_mips_rel(elf, sechdr, &r))
1878                                 continue;
1879                         break;
1880                 }
1881                 sym = elf->symtab_start + r_sym;
1882                 /* Skip special sections */
1883                 if (is_shndx_special(sym->st_shndx))
1884                         continue;
1885                 if (is_second_extable_reloc(start, rel, fromsec))
1886                         find_extable_entry_size(fromsec, &r);
1887                 check_section_mismatch(modname, elf, &r, sym, fromsec);
1888         }
1889 }
1890
1891 /**
1892  * A module includes a number of sections that are discarded
1893  * either when loaded or when used as built-in.
1894  * For loaded modules all functions marked __init and all data
1895  * marked __initdata will be discarded when the module has been initialized.
1896  * Likewise for modules used built-in the sections marked __exit
1897  * are discarded because __exit marked function are supposed to be called
1898  * only when a module is unloaded which never happens for built-in modules.
1899  * The check_sec_ref() function traverses all relocation records
1900  * to find all references to a section that reference a section that will
1901  * be discarded and warns about it.
1902  **/
1903 static void check_sec_ref(struct module *mod, const char *modname,
1904                           struct elf_info *elf)
1905 {
1906         int i;
1907         Elf_Shdr *sechdrs = elf->sechdrs;
1908
1909         /* Walk through all sections */
1910         for (i = 0; i < elf->num_sections; i++) {
1911                 check_section(modname, elf, &elf->sechdrs[i]);
1912                 /* We want to process only relocation sections and not .init */
1913                 if (sechdrs[i].sh_type == SHT_RELA)
1914                         section_rela(modname, elf, &elf->sechdrs[i]);
1915                 else if (sechdrs[i].sh_type == SHT_REL)
1916                         section_rel(modname, elf, &elf->sechdrs[i]);
1917         }
1918 }
1919
1920 static char *remove_dot(char *s)
1921 {
1922         size_t n = strcspn(s, ".");
1923
1924         if (n && s[n]) {
1925                 size_t m = strspn(s + n + 1, "0123456789");
1926                 if (m && (s[n + m] == '.' || s[n + m] == 0))
1927                         s[n] = 0;
1928         }
1929         return s;
1930 }
1931
1932 static void read_symbols(const char *modname)
1933 {
1934         const char *symname;
1935         char *version;
1936         char *license;
1937         struct module *mod;
1938         struct elf_info info = { };
1939         Elf_Sym *sym;
1940
1941         if (!parse_elf(&info, modname))
1942                 return;
1943
1944         mod = new_module(modname);
1945
1946         /* When there's no vmlinux, don't print warnings about
1947          * unresolved symbols (since there'll be too many ;) */
1948         if (is_vmlinux(modname)) {
1949                 have_vmlinux = 1;
1950                 mod->skip = 1;
1951         }
1952
1953         license = get_modinfo(&info, "license");
1954         if (!license && !is_vmlinux(modname))
1955                 warn("modpost: missing MODULE_LICENSE() in %s\n"
1956                      "see include/linux/module.h for "
1957                      "more information\n", modname);
1958         while (license) {
1959                 if (license_is_gpl_compatible(license))
1960                         mod->gpl_compatible = 1;
1961                 else {
1962                         mod->gpl_compatible = 0;
1963                         break;
1964                 }
1965                 license = get_next_modinfo(&info, "license", license);
1966         }
1967
1968         for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1969                 symname = remove_dot(info.strtab + sym->st_name);
1970
1971                 handle_modversions(mod, &info, sym, symname);
1972                 handle_moddevtable(mod, &info, sym, symname);
1973         }
1974         if (!is_vmlinux(modname) || vmlinux_section_warnings)
1975                 check_sec_ref(mod, modname, &info);
1976
1977         version = get_modinfo(&info, "version");
1978         if (version)
1979                 maybe_frob_rcs_version(modname, version, info.modinfo,
1980                                        version - (char *)info.hdr);
1981         if (version || (all_versions && !is_vmlinux(modname)))
1982                 get_src_version(modname, mod->srcversion,
1983                                 sizeof(mod->srcversion)-1);
1984
1985         parse_elf_finish(&info);
1986
1987         /* Our trick to get versioning for module struct etc. - it's
1988          * never passed as an argument to an exported function, so
1989          * the automatic versioning doesn't pick it up, but it's really
1990          * important anyhow */
1991         if (modversions)
1992                 mod->unres = alloc_symbol("module_layout", 0, mod->unres);
1993 }
1994
1995 static void read_symbols_from_files(const char *filename)
1996 {
1997         FILE *in = stdin;
1998         char fname[PATH_MAX];
1999
2000         if (strcmp(filename, "-") != 0) {
2001                 in = fopen(filename, "r");
2002                 if (!in)
2003                         fatal("Can't open filenames file %s: %m", filename);
2004         }
2005
2006         while (fgets(fname, PATH_MAX, in) != NULL) {
2007                 if (strends(fname, "\n"))
2008                         fname[strlen(fname)-1] = '\0';
2009                 read_symbols(fname);
2010         }
2011
2012         if (in != stdin)
2013                 fclose(in);
2014 }
2015
2016 #define SZ 500
2017
2018 /* We first write the generated file into memory using the
2019  * following helper, then compare to the file on disk and
2020  * only update the later if anything changed */
2021
2022 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
2023                                                       const char *fmt, ...)
2024 {
2025         char tmp[SZ];
2026         int len;
2027         va_list ap;
2028
2029         va_start(ap, fmt);
2030         len = vsnprintf(tmp, SZ, fmt, ap);
2031         buf_write(buf, tmp, len);
2032         va_end(ap);
2033 }
2034
2035 void buf_write(struct buffer *buf, const char *s, int len)
2036 {
2037         if (buf->size - buf->pos < len) {
2038                 buf->size += len + SZ;
2039                 buf->p = NOFAIL(realloc(buf->p, buf->size));
2040         }
2041         strncpy(buf->p + buf->pos, s, len);
2042         buf->pos += len;
2043 }
2044
2045 static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
2046 {
2047         const char *e = is_vmlinux(m) ?"":".ko";
2048
2049         switch (exp) {
2050         case export_gpl:
2051                 fatal("modpost: GPL-incompatible module %s%s "
2052                       "uses GPL-only symbol '%s'\n", m, e, s);
2053                 break;
2054         case export_unused_gpl:
2055                 fatal("modpost: GPL-incompatible module %s%s "
2056                       "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
2057                 break;
2058         case export_gpl_future:
2059                 warn("modpost: GPL-incompatible module %s%s "
2060                       "uses future GPL-only symbol '%s'\n", m, e, s);
2061                 break;
2062         case export_plain:
2063         case export_unused:
2064         case export_unknown:
2065                 /* ignore */
2066                 break;
2067         }
2068 }
2069
2070 static void check_for_unused(enum export exp, const char *m, const char *s)
2071 {
2072         const char *e = is_vmlinux(m) ?"":".ko";
2073
2074         switch (exp) {
2075         case export_unused:
2076         case export_unused_gpl:
2077                 warn("modpost: module %s%s "
2078                       "uses symbol '%s' marked UNUSED\n", m, e, s);
2079                 break;
2080         default:
2081                 /* ignore */
2082                 break;
2083         }
2084 }
2085
2086 static void check_exports(struct module *mod)
2087 {
2088         struct symbol *s, *exp;
2089
2090         for (s = mod->unres; s; s = s->next) {
2091                 const char *basename;
2092                 exp = find_symbol(s->name);
2093                 if (!exp || exp->module == mod)
2094                         continue;
2095                 basename = strrchr(mod->name, '/');
2096                 if (basename)
2097                         basename++;
2098                 else
2099                         basename = mod->name;
2100                 if (!mod->gpl_compatible)
2101                         check_for_gpl_usage(exp->export, basename, exp->name);
2102                 check_for_unused(exp->export, basename, exp->name);
2103         }
2104 }
2105
2106 static int check_modname_len(struct module *mod)
2107 {
2108         const char *mod_name;
2109
2110         mod_name = strrchr(mod->name, '/');
2111         if (mod_name == NULL)
2112                 mod_name = mod->name;
2113         else
2114                 mod_name++;
2115         if (strlen(mod_name) >= MODULE_NAME_LEN) {
2116                 merror("module name is too long [%s.ko]\n", mod->name);
2117                 return 1;
2118         }
2119
2120         return 0;
2121 }
2122
2123 /**
2124  * Header for the generated file
2125  **/
2126 static void add_header(struct buffer *b, struct module *mod)
2127 {
2128         buf_printf(b, "#include <linux/build-salt.h>\n");
2129         buf_printf(b, "#include <linux/module.h>\n");
2130         buf_printf(b, "#include <linux/vermagic.h>\n");
2131         buf_printf(b, "#include <linux/compiler.h>\n");
2132         buf_printf(b, "\n");
2133         buf_printf(b, "BUILD_SALT;\n");
2134         buf_printf(b, "\n");
2135         buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
2136         buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n");
2137         buf_printf(b, "\n");
2138         buf_printf(b, "__visible struct module __this_module\n");
2139         buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
2140         buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
2141         if (mod->has_init)
2142                 buf_printf(b, "\t.init = init_module,\n");
2143         if (mod->has_cleanup)
2144                 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
2145                               "\t.exit = cleanup_module,\n"
2146                               "#endif\n");
2147         buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
2148         buf_printf(b, "};\n");
2149 }
2150
2151 static void add_intree_flag(struct buffer *b, int is_intree)
2152 {
2153         if (is_intree)
2154                 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
2155 }
2156
2157 /* Cannot check for assembler */
2158 static void add_retpoline(struct buffer *b)
2159 {
2160         buf_printf(b, "\n#ifdef RETPOLINE\n");
2161         buf_printf(b, "MODULE_INFO(retpoline, \"Y\");\n");
2162         buf_printf(b, "#endif\n");
2163 }
2164
2165 static void add_staging_flag(struct buffer *b, const char *name)
2166 {
2167         if (strstarts(name, "drivers/staging"))
2168                 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
2169 }
2170
2171 /**
2172  * Record CRCs for unresolved symbols
2173  **/
2174 static int add_versions(struct buffer *b, struct module *mod)
2175 {
2176         struct symbol *s, *exp;
2177         int err = 0;
2178
2179         for (s = mod->unres; s; s = s->next) {
2180                 exp = find_symbol(s->name);
2181                 if (!exp || exp->module == mod) {
2182                         if (have_vmlinux && !s->weak) {
2183                                 if (warn_unresolved) {
2184                                         warn("\"%s\" [%s.ko] undefined!\n",
2185                                              s->name, mod->name);
2186                                 } else {
2187                                         merror("\"%s\" [%s.ko] undefined!\n",
2188                                                s->name, mod->name);
2189                                         err = 1;
2190                                 }
2191                         }
2192                         continue;
2193                 }
2194                 s->module = exp->module;
2195                 s->crc_valid = exp->crc_valid;
2196                 s->crc = exp->crc;
2197         }
2198
2199         if (!modversions)
2200                 return err;
2201
2202         buf_printf(b, "\n");
2203         buf_printf(b, "static const struct modversion_info ____versions[]\n");
2204         buf_printf(b, "__used\n");
2205         buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
2206
2207         for (s = mod->unres; s; s = s->next) {
2208                 if (!s->module)
2209                         continue;
2210                 if (!s->crc_valid) {
2211                         warn("\"%s\" [%s.ko] has no CRC!\n",
2212                                 s->name, mod->name);
2213                         continue;
2214                 }
2215                 if (strlen(s->name) >= MODULE_NAME_LEN) {
2216                         merror("too long symbol \"%s\" [%s.ko]\n",
2217                                s->name, mod->name);
2218                         err = 1;
2219                         break;
2220                 }
2221                 buf_printf(b, "\t{ %#8x, \"%s\" },\n",
2222                            s->crc, s->name);
2223         }
2224
2225         buf_printf(b, "};\n");
2226
2227         return err;
2228 }
2229
2230 static void add_depends(struct buffer *b, struct module *mod,
2231                         struct module *modules)
2232 {
2233         struct symbol *s;
2234         struct module *m;
2235         int first = 1;
2236
2237         for (m = modules; m; m = m->next)
2238                 m->seen = is_vmlinux(m->name);
2239
2240         buf_printf(b, "\n");
2241         buf_printf(b, "static const char __module_depends[]\n");
2242         buf_printf(b, "__used\n");
2243         buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
2244         buf_printf(b, "\"depends=");
2245         for (s = mod->unres; s; s = s->next) {
2246                 const char *p;
2247                 if (!s->module)
2248                         continue;
2249
2250                 if (s->module->seen)
2251                         continue;
2252
2253                 s->module->seen = 1;
2254                 p = strrchr(s->module->name, '/');
2255                 if (p)
2256                         p++;
2257                 else
2258                         p = s->module->name;
2259                 buf_printf(b, "%s%s", first ? "" : ",", p);
2260                 first = 0;
2261         }
2262         buf_printf(b, "\";\n");
2263 }
2264
2265 static void add_srcversion(struct buffer *b, struct module *mod)
2266 {
2267         if (mod->srcversion[0]) {
2268                 buf_printf(b, "\n");
2269                 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
2270                            mod->srcversion);
2271         }
2272 }
2273
2274 static void write_if_changed(struct buffer *b, const char *fname)
2275 {
2276         char *tmp;
2277         FILE *file;
2278         struct stat st;
2279
2280         file = fopen(fname, "r");
2281         if (!file)
2282                 goto write;
2283
2284         if (fstat(fileno(file), &st) < 0)
2285                 goto close_write;
2286
2287         if (st.st_size != b->pos)
2288                 goto close_write;
2289
2290         tmp = NOFAIL(malloc(b->pos));
2291         if (fread(tmp, 1, b->pos, file) != b->pos)
2292                 goto free_write;
2293
2294         if (memcmp(tmp, b->p, b->pos) != 0)
2295                 goto free_write;
2296
2297         free(tmp);
2298         fclose(file);
2299         return;
2300
2301  free_write:
2302         free(tmp);
2303  close_write:
2304         fclose(file);
2305  write:
2306         file = fopen(fname, "w");
2307         if (!file) {
2308                 perror(fname);
2309                 exit(1);
2310         }
2311         if (fwrite(b->p, 1, b->pos, file) != b->pos) {
2312                 perror(fname);
2313                 exit(1);
2314         }
2315         fclose(file);
2316 }
2317
2318 /* parse Module.symvers file. line format:
2319  * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
2320  **/
2321 static void read_dump(const char *fname, unsigned int kernel)
2322 {
2323         unsigned long size, pos = 0;
2324         void *file = grab_file(fname, &size);
2325         char *line;
2326
2327         if (!file)
2328                 /* No symbol versions, silently ignore */
2329                 return;
2330
2331         while ((line = get_next_line(&pos, file, size))) {
2332                 char *symname, *modname, *d, *export, *end;
2333                 unsigned int crc;
2334                 struct module *mod;
2335                 struct symbol *s;
2336
2337                 if (!(symname = strchr(line, '\t')))
2338                         goto fail;
2339                 *symname++ = '\0';
2340                 if (!(modname = strchr(symname, '\t')))
2341                         goto fail;
2342                 *modname++ = '\0';
2343                 if ((export = strchr(modname, '\t')) != NULL)
2344                         *export++ = '\0';
2345                 if (export && ((end = strchr(export, '\t')) != NULL))
2346                         *end = '\0';
2347                 crc = strtoul(line, &d, 16);
2348                 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2349                         goto fail;
2350                 mod = find_module(modname);
2351                 if (!mod) {
2352                         if (is_vmlinux(modname))
2353                                 have_vmlinux = 1;
2354                         mod = new_module(modname);
2355                         mod->skip = 1;
2356                 }
2357                 s = sym_add_exported(symname, mod, export_no(export));
2358                 s->kernel    = kernel;
2359                 s->preloaded = 1;
2360                 sym_update_crc(symname, mod, crc, export_no(export));
2361         }
2362         release_file(file, size);
2363         return;
2364 fail:
2365         release_file(file, size);
2366         fatal("parse error in symbol dump file\n");
2367 }
2368
2369 /* For normal builds always dump all symbols.
2370  * For external modules only dump symbols
2371  * that are not read from kernel Module.symvers.
2372  **/
2373 static int dump_sym(struct symbol *sym)
2374 {
2375         if (!external_module)
2376                 return 1;
2377         if (sym->vmlinux || sym->kernel)
2378                 return 0;
2379         return 1;
2380 }
2381
2382 static void write_dump(const char *fname)
2383 {
2384         struct buffer buf = { };
2385         struct symbol *symbol;
2386         int n;
2387
2388         for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
2389                 symbol = symbolhash[n];
2390                 while (symbol) {
2391                         if (dump_sym(symbol))
2392                                 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
2393                                         symbol->crc, symbol->name,
2394                                         symbol->module->name,
2395                                         export_str(symbol->export));
2396                         symbol = symbol->next;
2397                 }
2398         }
2399         write_if_changed(&buf, fname);
2400         free(buf.p);
2401 }
2402
2403 struct ext_sym_list {
2404         struct ext_sym_list *next;
2405         const char *file;
2406 };
2407
2408 int main(int argc, char **argv)
2409 {
2410         struct module *mod;
2411         struct buffer buf = { };
2412         char *kernel_read = NULL, *module_read = NULL;
2413         char *dump_write = NULL, *files_source = NULL;
2414         int opt;
2415         int err;
2416         struct ext_sym_list *extsym_iter;
2417         struct ext_sym_list *extsym_start = NULL;
2418
2419         while ((opt = getopt(argc, argv, "i:I:e:mnsST:o:awM:K:E")) != -1) {
2420                 switch (opt) {
2421                 case 'i':
2422                         kernel_read = optarg;
2423                         break;
2424                 case 'I':
2425                         module_read = optarg;
2426                         external_module = 1;
2427                         break;
2428                 case 'e':
2429                         external_module = 1;
2430                         extsym_iter =
2431                            NOFAIL(malloc(sizeof(*extsym_iter)));
2432                         extsym_iter->next = extsym_start;
2433                         extsym_iter->file = optarg;
2434                         extsym_start = extsym_iter;
2435                         break;
2436                 case 'm':
2437                         modversions = 1;
2438                         break;
2439                 case 'n':
2440                         ignore_missing_files = 1;
2441                         break;
2442                 case 'o':
2443                         dump_write = optarg;
2444                         break;
2445                 case 'a':
2446                         all_versions = 1;
2447                         break;
2448                 case 's':
2449                         vmlinux_section_warnings = 0;
2450                         break;
2451                 case 'S':
2452                         sec_mismatch_verbose = 0;
2453                         break;
2454                 case 'T':
2455                         files_source = optarg;
2456                         break;
2457                 case 'w':
2458                         warn_unresolved = 1;
2459                         break;
2460                 case 'E':
2461                         sec_mismatch_fatal = 1;
2462                         break;
2463                 default:
2464                         exit(1);
2465                 }
2466         }
2467
2468         if (kernel_read)
2469                 read_dump(kernel_read, 1);
2470         if (module_read)
2471                 read_dump(module_read, 0);
2472         while (extsym_start) {
2473                 read_dump(extsym_start->file, 0);
2474                 extsym_iter = extsym_start->next;
2475                 free(extsym_start);
2476                 extsym_start = extsym_iter;
2477         }
2478
2479         while (optind < argc)
2480                 read_symbols(argv[optind++]);
2481
2482         if (files_source)
2483                 read_symbols_from_files(files_source);
2484
2485         for (mod = modules; mod; mod = mod->next) {
2486                 if (mod->skip)
2487                         continue;
2488                 check_exports(mod);
2489         }
2490
2491         err = 0;
2492
2493         for (mod = modules; mod; mod = mod->next) {
2494                 char fname[PATH_MAX];
2495
2496                 if (mod->skip)
2497                         continue;
2498
2499                 buf.pos = 0;
2500
2501                 err |= check_modname_len(mod);
2502                 add_header(&buf, mod);
2503                 add_intree_flag(&buf, !external_module);
2504                 add_retpoline(&buf);
2505                 add_staging_flag(&buf, mod->name);
2506                 err |= add_versions(&buf, mod);
2507                 add_depends(&buf, mod, modules);
2508                 add_moddevtable(&buf, mod);
2509                 add_srcversion(&buf, mod);
2510
2511                 sprintf(fname, "%s.mod.c", mod->name);
2512                 write_if_changed(&buf, fname);
2513         }
2514         if (dump_write)
2515                 write_dump(dump_write);
2516         if (sec_mismatch_count) {
2517                 if (!sec_mismatch_verbose) {
2518                         warn("modpost: Found %d section mismatch(es).\n"
2519                              "To see full details build your kernel with:\n"
2520                              "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n",
2521                              sec_mismatch_count);
2522                 }
2523                 if (sec_mismatch_fatal) {
2524                         fatal("modpost: Section mismatches detected.\n"
2525                               "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");
2526                 }
2527         }
2528         free(buf.p);
2529
2530         return err;
2531 }