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 <elf.h>
  16 #include <fnmatch.h>
  17 #include <stdio.h>
  18 #include <ctype.h>
  19 #include <string.h>
  20 #include <limits.h>
  21 #include <stdbool.h>
  22 #include <errno.h>
  23 #include "modpost.h"
  24 #include "../../include/linux/license.h"
  25
  26 static bool module_enabled;
  27 /* Are we using CONFIG_MODVERSIONS? */
  28 static bool modversions;
  29 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */
  30 static bool all_versions;
  31 /* If we are modposting external module set to 1 */
  32 static bool external_module;
  33 /* Only warn about unresolved symbols */
  34 static bool warn_unresolved;
  35
  36 static int sec_mismatch_count;
  37 static bool sec_mismatch_warn_only = true;
  38 /* Trim EXPORT_SYMBOLs that are unused by in-tree modules */
  39 static bool trim_unused_exports;
  40
  41 /* ignore missing files */
  42 static bool ignore_missing_files;
  43 /* If set to 1, only warn (instead of error) about missing ns imports */
  44 static bool allow_missing_ns_imports;
  45
  46 static bool error_occurred;
  47
  48 static bool extra_warn;
  49
  50 /*
  51  * Cut off the warnings when there are too many. This typically occurs when
  52  * vmlinux is missing. ('make modules' without building vmlinux.)
  53  */
  54 #define MAX_UNRESOLVED_REPORTS  10
  55 static unsigned int nr_unresolved;
  56
  57 /* In kernel, this size is defined in linux/module.h;
  58  * here we use Elf_Addr instead of long for covering cross-compile
  59  */
  60
  61 #define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
  62
  63 void modpost_log(enum loglevel loglevel, const char *fmt, ...)
  64 {
  65         va_list arglist;
  66
  67         switch (loglevel) {
  68         case LOG_WARN:
  69                 fprintf(stderr, "WARNING: ");
  70                 break;
  71         case LOG_ERROR:
  72                 fprintf(stderr, "ERROR: ");
  73                 error_occurred = true;
  74                 break;
  75         default: /* invalid loglevel, ignore */
  76                 break;
  77         }
  78
  79         fprintf(stderr, "modpost: ");
  80
  81         va_start(arglist, fmt);
  82         vfprintf(stderr, fmt, arglist);
  83         va_end(arglist);
  84 }
  85
  86 static inline bool strends(const char *str, const char *postfix)
  87 {
  88         if (strlen(str) < strlen(postfix))
  89                 return false;
  90
  91         return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0;
  92 }
  93
  94 void *do_nofail(void *ptr, const char *expr)
  95 {
  96         if (!ptr)
  97                 fatal("Memory allocation failure: %s.\n", expr);
  98
  99         return ptr;
 100 }
 101
 102 char *read_text_file(const char *filename)
 103 {
 104         struct stat st;
 105         size_t nbytes;
 106         int fd;
 107         char *buf;
 108
 109         fd = open(filename, O_RDONLY);
 110         if (fd < 0) {
 111                 perror(filename);
 112                 exit(1);
 113         }
 114
 115         if (fstat(fd, &st) < 0) {
 116                 perror(filename);
 117                 exit(1);
 118         }
 119
 120         buf = NOFAIL(malloc(st.st_size + 1));
 121
 122         nbytes = st.st_size;
 123
 124         while (nbytes) {
 125                 ssize_t bytes_read;
 126
 127                 bytes_read = read(fd, buf, nbytes);
 128                 if (bytes_read < 0) {
 129                         perror(filename);
 130                         exit(1);
 131                 }
 132
 133                 nbytes -= bytes_read;
 134         }
 135         buf[st.st_size] = '\0';
 136
 137         close(fd);
 138
 139         return buf;
 140 }
 141
 142 char *get_line(char **stringp)
 143 {
 144         char *orig = *stringp, *next;
 145
 146         /* do not return the unwanted extra line at EOF */
 147         if (!orig || *orig == '\0')
 148                 return NULL;
 149
 150         /* don't use strsep here, it is not available everywhere */
 151         next = strchr(orig, '\n');
 152         if (next)
 153                 *next++ = '\0';
 154
 155         *stringp = next;
 156
 157         return orig;
 158 }
 159
 160 /* A list of all modules we processed */
 161 LIST_HEAD(modules);
 162
 163 static struct module *find_module(const char *modname)
 164 {
 165         struct module *mod;
 166
 167         list_for_each_entry(mod, &modules, list) {
 168                 if (strcmp(mod->name, modname) == 0)
 169                         return mod;
 170         }
 171         return NULL;
 172 }
 173
 174 static struct module *new_module(const char *name, size_t namelen)
 175 {
 176         struct module *mod;
 177
 178         mod = NOFAIL(malloc(sizeof(*mod) + namelen + 1));
 179         memset(mod, 0, sizeof(*mod));
 180
 181         INIT_LIST_HEAD(&mod->exported_symbols);
 182         INIT_LIST_HEAD(&mod->unresolved_symbols);
 183         INIT_LIST_HEAD(&mod->missing_namespaces);
 184         INIT_LIST_HEAD(&mod->imported_namespaces);
 185
 186         memcpy(mod->name, name, namelen);
 187         mod->name[namelen] = '\0';
 188         mod->is_vmlinux = (strcmp(mod->name, "vmlinux") == 0);
 189
 190         /*
 191          * Set mod->is_gpl_compatible to true by default. If MODULE_LICENSE()
 192          * is missing, do not check the use for EXPORT_SYMBOL_GPL() becasue
 193          * modpost will exit wiht error anyway.
 194          */
 195         mod->is_gpl_compatible = true;
 196
 197         list_add_tail(&mod->list, &modules);
 198
 199         return mod;
 200 }
 201
 202 /* A hash of all exported symbols,
 203  * struct symbol is also used for lists of unresolved symbols */
 204
 205 #define SYMBOL_HASH_SIZE 1024
 206
 207 struct symbol {
 208         struct symbol *next;
 209         struct list_head list;  /* link to module::exported_symbols or module::unresolved_symbols */
 210         struct module *module;
 211         char *namespace;
 212         unsigned int crc;
 213         bool crc_valid;
 214         bool weak;
 215         bool is_func;
 216         bool is_gpl_only;       /* exported by EXPORT_SYMBOL_GPL */
 217         bool used;              /* there exists a user of this symbol */
 218         char name[];
 219 };
 220
 221 static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
 222
 223 /* This is based on the hash algorithm from gdbm, via tdb */
 224 static inline unsigned int tdb_hash(const char *name)
 225 {
 226         unsigned value; /* Used to compute the hash value.  */
 227         unsigned   i;   /* Used to cycle through random values. */
 228
 229         /* Set the initial value from the key size. */
 230         for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
 231                 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
 232
 233         return (1103515243 * value + 12345);
 234 }
 235
 236 /**
 237  * Allocate a new symbols for use in the hash of exported symbols or
 238  * the list of unresolved symbols per module
 239  **/
 240 static struct symbol *alloc_symbol(const char *name)
 241 {
 242         struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
 243
 244         memset(s, 0, sizeof(*s));
 245         strcpy(s->name, name);
 246
 247         return s;
 248 }
 249
 250 /* For the hash of exported symbols */
 251 static void hash_add_symbol(struct symbol *sym)
 252 {
 253         unsigned int hash;
 254
 255         hash = tdb_hash(sym->name) % SYMBOL_HASH_SIZE;
 256         sym->next = symbolhash[hash];
 257         symbolhash[hash] = sym;
 258 }
 259
 260 static void sym_add_unresolved(const char *name, struct module *mod, bool weak)
 261 {
 262         struct symbol *sym;
 263
 264         sym = alloc_symbol(name);
 265         sym->weak = weak;
 266
 267         list_add_tail(&sym->list, &mod->unresolved_symbols);
 268 }
 269
 270 static struct symbol *sym_find_with_module(const char *name, struct module *mod)
 271 {
 272         struct symbol *s;
 273
 274         /* For our purposes, .foo matches foo.  PPC64 needs this. */
 275         if (name[0] == '.')
 276                 name++;
 277
 278         for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
 279                 if (strcmp(s->name, name) == 0 && (!mod || s->module == mod))
 280                         return s;
 281         }
 282         return NULL;
 283 }
 284
 285 static struct symbol *find_symbol(const char *name)
 286 {
 287         return sym_find_with_module(name, NULL);
 288 }
 289
 290 struct namespace_list {
 291         struct list_head list;
 292         char namespace[];
 293 };
 294
 295 static bool contains_namespace(struct list_head *head, const char *namespace)
 296 {
 297         struct namespace_list *list;
 298
 299         /*
 300          * The default namespace is null string "", which is always implicitly
 301          * contained.
 302          */
 303         if (!namespace[0])
 304                 return true;
 305
 306         list_for_each_entry(list, head, list) {
 307                 if (!strcmp(list->namespace, namespace))
 308                         return true;
 309         }
 310
 311         return false;
 312 }
 313
 314 static void add_namespace(struct list_head *head, const char *namespace)
 315 {
 316         struct namespace_list *ns_entry;
 317
 318         if (!contains_namespace(head, namespace)) {
 319                 ns_entry = NOFAIL(malloc(sizeof(*ns_entry) +
 320                                          strlen(namespace) + 1));
 321                 strcpy(ns_entry->namespace, namespace);
 322                 list_add_tail(&ns_entry->list, head);
 323         }
 324 }
 325
 326 static void *sym_get_data_by_offset(const struct elf_info *info,
 327                                     unsigned int secindex, unsigned long offset)
 328 {
 329         Elf_Shdr *sechdr = &info->sechdrs[secindex];
 330
 331         return (void *)info->hdr + sechdr->sh_offset + offset;
 332 }
 333
 334 void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym)
 335 {
 336         return sym_get_data_by_offset(info, get_secindex(info, sym),
 337                                       sym->st_value);
 338 }
 339
 340 static const char *sech_name(const struct elf_info *info, Elf_Shdr *sechdr)
 341 {
 342         return sym_get_data_by_offset(info, info->secindex_strings,
 343                                       sechdr->sh_name);
 344 }
 345
 346 static const char *sec_name(const struct elf_info *info, unsigned int secindex)
 347 {
 348         /*
 349          * If sym->st_shndx is a special section index, there is no
 350          * corresponding section header.
 351          * Return "" if the index is out of range of info->sechdrs[] array.
 352          */
 353         if (secindex >= info->num_sections)
 354                 return "";
 355
 356         return sech_name(info, &info->sechdrs[secindex]);
 357 }
 358
 359 #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)
 360
 361 static struct symbol *sym_add_exported(const char *name, struct module *mod,
 362                                        bool gpl_only, const char *namespace)
 363 {
 364         struct symbol *s = find_symbol(name);
 365
 366         if (s && (!external_module || s->module->is_vmlinux || s->module == mod)) {
 367                 error("%s: '%s' exported twice. Previous export was in %s%s\n",
 368                       mod->name, name, s->module->name,
 369                       s->module->is_vmlinux ? "" : ".ko");
 370         }
 371
 372         s = alloc_symbol(name);
 373         s->module = mod;
 374         s->is_gpl_only = gpl_only;
 375         s->namespace = NOFAIL(strdup(namespace));
 376         list_add_tail(&s->list, &mod->exported_symbols);
 377         hash_add_symbol(s);
 378
 379         return s;
 380 }
 381
 382 static void sym_set_crc(struct symbol *sym, unsigned int crc)
 383 {
 384         sym->crc = crc;
 385         sym->crc_valid = true;
 386 }
 387
 388 static void *grab_file(const char *filename, size_t *size)
 389 {
 390         struct stat st;
 391         void *map = MAP_FAILED;
 392         int fd;
 393
 394         fd = open(filename, O_RDONLY);
 395         if (fd < 0)
 396                 return NULL;
 397         if (fstat(fd, &st))
 398                 goto failed;
 399
 400         *size = st.st_size;
 401         map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
 402
 403 failed:
 404         close(fd);
 405         if (map == MAP_FAILED)
 406                 return NULL;
 407         return map;
 408 }
 409
 410 static void release_file(void *file, size_t size)
 411 {
 412         munmap(file, size);
 413 }
 414
 415 static int parse_elf(struct elf_info *info, const char *filename)
 416 {
 417         unsigned int i;
 418         Elf_Ehdr *hdr;
 419         Elf_Shdr *sechdrs;
 420         Elf_Sym  *sym;
 421         const char *secstrings;
 422         unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
 423
 424         hdr = grab_file(filename, &info->size);
 425         if (!hdr) {
 426                 if (ignore_missing_files) {
 427                         fprintf(stderr, "%s: %s (ignored)\n", filename,
 428                                 strerror(errno));
 429                         return 0;
 430                 }
 431                 perror(filename);
 432                 exit(1);
 433         }
 434         info->hdr = hdr;
 435         if (info->size < sizeof(*hdr)) {
 436                 /* file too small, assume this is an empty .o file */
 437                 return 0;
 438         }
 439         /* Is this a valid ELF file? */
 440         if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
 441             (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
 442             (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
 443             (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
 444                 /* Not an ELF file - silently ignore it */
 445                 return 0;
 446         }
 447         /* Fix endianness in ELF header */
 448         hdr->e_type      = TO_NATIVE(hdr->e_type);
 449         hdr->e_machine   = TO_NATIVE(hdr->e_machine);
 450         hdr->e_version   = TO_NATIVE(hdr->e_version);
 451         hdr->e_entry     = TO_NATIVE(hdr->e_entry);
 452         hdr->e_phoff     = TO_NATIVE(hdr->e_phoff);
 453         hdr->e_shoff     = TO_NATIVE(hdr->e_shoff);
 454         hdr->e_flags     = TO_NATIVE(hdr->e_flags);
 455         hdr->e_ehsize    = TO_NATIVE(hdr->e_ehsize);
 456         hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
 457         hdr->e_phnum     = TO_NATIVE(hdr->e_phnum);
 458         hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
 459         hdr->e_shnum     = TO_NATIVE(hdr->e_shnum);
 460         hdr->e_shstrndx  = TO_NATIVE(hdr->e_shstrndx);
 461         sechdrs = (void *)hdr + hdr->e_shoff;
 462         info->sechdrs = sechdrs;
 463
 464         /* modpost only works for relocatable objects */
 465         if (hdr->e_type != ET_REL)
 466                 fatal("%s: not relocatable object.", filename);
 467
 468         /* Check if file offset is correct */
 469         if (hdr->e_shoff > info->size)
 470                 fatal("section header offset=%lu in file '%s' is bigger than filesize=%zu\n",
 471                       (unsigned long)hdr->e_shoff, filename, info->size);
 472
 473         if (hdr->e_shnum == SHN_UNDEF) {
 474                 /*
 475                  * There are more than 64k sections,
 476                  * read count from .sh_size.
 477                  */
 478                 info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
 479         }
 480         else {
 481                 info->num_sections = hdr->e_shnum;
 482         }
 483         if (hdr->e_shstrndx == SHN_XINDEX) {
 484                 info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
 485         }
 486         else {
 487                 info->secindex_strings = hdr->e_shstrndx;
 488         }
 489
 490         /* Fix endianness in section headers */
 491         for (i = 0; i < info->num_sections; i++) {
 492                 sechdrs[i].sh_name      = TO_NATIVE(sechdrs[i].sh_name);
 493                 sechdrs[i].sh_type      = TO_NATIVE(sechdrs[i].sh_type);
 494                 sechdrs[i].sh_flags     = TO_NATIVE(sechdrs[i].sh_flags);
 495                 sechdrs[i].sh_addr      = TO_NATIVE(sechdrs[i].sh_addr);
 496                 sechdrs[i].sh_offset    = TO_NATIVE(sechdrs[i].sh_offset);
 497                 sechdrs[i].sh_size      = TO_NATIVE(sechdrs[i].sh_size);
 498                 sechdrs[i].sh_link      = TO_NATIVE(sechdrs[i].sh_link);
 499                 sechdrs[i].sh_info      = TO_NATIVE(sechdrs[i].sh_info);
 500                 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
 501                 sechdrs[i].sh_entsize   = TO_NATIVE(sechdrs[i].sh_entsize);
 502         }
 503         /* Find symbol table. */
 504         secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
 505         for (i = 1; i < info->num_sections; i++) {
 506                 const char *secname;
 507                 int nobits = sechdrs[i].sh_type == SHT_NOBITS;
 508
 509                 if (!nobits && sechdrs[i].sh_offset > info->size)
 510                         fatal("%s is truncated. sechdrs[i].sh_offset=%lu > sizeof(*hrd)=%zu\n",
 511                               filename, (unsigned long)sechdrs[i].sh_offset,
 512                               sizeof(*hdr));
 513
 514                 secname = secstrings + sechdrs[i].sh_name;
 515                 if (strcmp(secname, ".modinfo") == 0) {
 516                         if (nobits)
 517                                 fatal("%s has NOBITS .modinfo\n", filename);
 518                         info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
 519                         info->modinfo_len = sechdrs[i].sh_size;
 520                 } else if (!strcmp(secname, ".export_symbol")) {
 521                         info->export_symbol_secndx = i;
 522                 }
 523
 524                 if (sechdrs[i].sh_type == SHT_SYMTAB) {
 525                         unsigned int sh_link_idx;
 526                         symtab_idx = i;
 527                         info->symtab_start = (void *)hdr +
 528                             sechdrs[i].sh_offset;
 529                         info->symtab_stop  = (void *)hdr +
 530                             sechdrs[i].sh_offset + sechdrs[i].sh_size;
 531                         sh_link_idx = sechdrs[i].sh_link;
 532                         info->strtab       = (void *)hdr +
 533                             sechdrs[sh_link_idx].sh_offset;
 534                 }
 535
 536                 /* 32bit section no. table? ("more than 64k sections") */
 537                 if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
 538                         symtab_shndx_idx = i;
 539                         info->symtab_shndx_start = (void *)hdr +
 540                             sechdrs[i].sh_offset;
 541                         info->symtab_shndx_stop  = (void *)hdr +
 542                             sechdrs[i].sh_offset + sechdrs[i].sh_size;
 543                 }
 544         }
 545         if (!info->symtab_start)
 546                 fatal("%s has no symtab?\n", filename);
 547
 548         /* Fix endianness in symbols */
 549         for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
 550                 sym->st_shndx = TO_NATIVE(sym->st_shndx);
 551                 sym->st_name  = TO_NATIVE(sym->st_name);
 552                 sym->st_value = TO_NATIVE(sym->st_value);
 553                 sym->st_size  = TO_NATIVE(sym->st_size);
 554         }
 555
 556         if (symtab_shndx_idx != ~0U) {
 557                 Elf32_Word *p;
 558                 if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
 559                         fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
 560                               filename, sechdrs[symtab_shndx_idx].sh_link,
 561                               symtab_idx);
 562                 /* Fix endianness */
 563                 for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
 564                      p++)
 565                         *p = TO_NATIVE(*p);
 566         }
 567
 568         symsearch_init(info);
 569
 570         return 1;
 571 }
 572
 573 static void parse_elf_finish(struct elf_info *info)
 574 {
 575         symsearch_finish(info);
 576         release_file(info->hdr, info->size);
 577 }
 578
 579 static int ignore_undef_symbol(struct elf_info *info, const char *symname)
 580 {
 581         /* ignore __this_module, it will be resolved shortly */
 582         if (strcmp(symname, "__this_module") == 0)
 583                 return 1;
 584         /* ignore global offset table */
 585         if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
 586                 return 1;
 587         if (info->hdr->e_machine == EM_PPC)
 588                 /* Special register function linked on all modules during final link of .ko */
 589                 if (strstarts(symname, "_restgpr_") ||
 590                     strstarts(symname, "_savegpr_") ||
 591                     strstarts(symname, "_rest32gpr_") ||
 592                     strstarts(symname, "_save32gpr_") ||
 593                     strstarts(symname, "_restvr_") ||
 594                     strstarts(symname, "_savevr_"))
 595                         return 1;
 596         if (info->hdr->e_machine == EM_PPC64)
 597                 /* Special register function linked on all modules during final link of .ko */
 598                 if (strstarts(symname, "_restgpr0_") ||
 599                     strstarts(symname, "_savegpr0_") ||
 600                     strstarts(symname, "_restvr_") ||
 601                     strstarts(symname, "_savevr_") ||
 602                     strcmp(symname, ".TOC.") == 0)
 603                         return 1;
 604
 605         if (info->hdr->e_machine == EM_S390)
 606                 /* Expoline thunks are linked on all kernel modules during final link of .ko */
 607                 if (strstarts(symname, "__s390_indirect_jump_r"))
 608                         return 1;
 609         /* Do not ignore this symbol */
 610         return 0;
 611 }
 612
 613 static void handle_symbol(struct module *mod, struct elf_info *info,
 614                           const Elf_Sym *sym, const char *symname)
 615 {
 616         switch (sym->st_shndx) {
 617         case SHN_COMMON:
 618                 if (strstarts(symname, "__gnu_lto_")) {
 619                         /* Should warn here, but modpost runs before the linker */
 620                 } else
 621                         warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
 622                 break;
 623         case SHN_UNDEF:
 624                 /* undefined symbol */
 625                 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
 626                     ELF_ST_BIND(sym->st_info) != STB_WEAK)
 627                         break;
 628                 if (ignore_undef_symbol(info, symname))
 629                         break;
 630                 if (info->hdr->e_machine == EM_SPARC ||
 631                     info->hdr->e_machine == EM_SPARCV9) {
 632                         /* Ignore register directives. */
 633                         if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
 634                                 break;
 635                         if (symname[0] == '.') {
 636                                 char *munged = NOFAIL(strdup(symname));
 637                                 munged[0] = '_';
 638                                 munged[1] = toupper(munged[1]);
 639                                 symname = munged;
 640                         }
 641                 }
 642
 643                 sym_add_unresolved(symname, mod,
 644                                    ELF_ST_BIND(sym->st_info) == STB_WEAK);
 645                 break;
 646         default:
 647                 if (strcmp(symname, "init_module") == 0)
 648                         mod->has_init = true;
 649                 if (strcmp(symname, "cleanup_module") == 0)
 650                         mod->has_cleanup = true;
 651                 break;
 652         }
 653 }
 654
 655 /**
 656  * Parse tag=value strings from .modinfo section
 657  **/
 658 static char *next_string(char *string, unsigned long *secsize)
 659 {
 660         /* Skip non-zero chars */
 661         while (string[0]) {
 662                 string++;
 663                 if ((*secsize)-- <= 1)
 664                         return NULL;
 665         }
 666
 667         /* Skip any zero padding. */
 668         while (!string[0]) {
 669                 string++;
 670                 if ((*secsize)-- <= 1)
 671                         return NULL;
 672         }
 673         return string;
 674 }
 675
 676 static char *get_next_modinfo(struct elf_info *info, const char *tag,
 677                               char *prev)
 678 {
 679         char *p;
 680         unsigned int taglen = strlen(tag);
 681         char *modinfo = info->modinfo;
 682         unsigned long size = info->modinfo_len;
 683
 684         if (prev) {
 685                 size -= prev - modinfo;
 686                 modinfo = next_string(prev, &size);
 687         }
 688
 689         for (p = modinfo; p; p = next_string(p, &size)) {
 690                 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
 691                         return p + taglen + 1;
 692         }
 693         return NULL;
 694 }
 695
 696 static char *get_modinfo(struct elf_info *info, const char *tag)
 697
 698 {
 699         return get_next_modinfo(info, tag, NULL);
 700 }
 701
 702 static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
 703 {
 704         if (sym)
 705                 return elf->strtab + sym->st_name;
 706         else
 707                 return "(unknown)";
 708 }
 709
 710 /*
 711  * Check whether the 'string' argument matches one of the 'patterns',
 712  * an array of shell wildcard patterns (glob).
 713  *
 714  * Return true is there is a match.
 715  */
 716 static bool match(const char *string, const char *const patterns[])
 717 {
 718         const char *pattern;
 719
 720         while ((pattern = *patterns++)) {
 721                 if (!fnmatch(pattern, string, 0))
 722                         return true;
 723         }
 724
 725         return false;
 726 }
 727
 728 /* useful to pass patterns to match() directly */
 729 #define PATTERNS(...) \
 730         ({ \
 731                 static const char *const patterns[] = {__VA_ARGS__, NULL}; \
 732                 patterns; \
 733         })
 734
 735 /* sections that we do not want to do full section mismatch check on */
 736 static const char *const section_white_list[] =
 737 {
 738         ".comment*",
 739         ".debug*",
 740         ".zdebug*",             /* Compressed debug sections. */
 741         ".GCC.command.line",    /* record-gcc-switches */
 742         ".mdebug*",        /* alpha, score, mips etc. */
 743         ".pdr",            /* alpha, score, mips etc. */
 744         ".stab*",
 745         ".note*",
 746         ".got*",
 747         ".toc*",
 748         ".xt.prop",                              /* xtensa */
 749         ".xt.lit",         /* xtensa */
 750         ".arcextmap*",                  /* arc */
 751         ".gnu.linkonce.arcext*",        /* arc : modules */
 752         ".cmem*",                       /* EZchip */
 753         ".fmt_slot*",                   /* EZchip */
 754         ".gnu.lto*",
 755         ".discard.*",
 756         ".llvm.call-graph-profile",     /* call graph */
 757         NULL
 758 };
 759
 760 /*
 761  * This is used to find sections missing the SHF_ALLOC flag.
 762  * The cause of this is often a section specified in assembler
 763  * without "ax" / "aw".
 764  */
 765 static void check_section(const char *modname, struct elf_info *elf,
 766                           Elf_Shdr *sechdr)
 767 {
 768         const char *sec = sech_name(elf, sechdr);
 769
 770         if (sechdr->sh_type == SHT_PROGBITS &&
 771             !(sechdr->sh_flags & SHF_ALLOC) &&
 772             !match(sec, section_white_list)) {
 773                 warn("%s (%s): unexpected non-allocatable section.\n"
 774                      "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
 775                      "Note that for example <linux/init.h> contains\n"
 776                      "section definitions for use in .S files.\n\n",
 777                      modname, sec);
 778         }
 779 }
 780
 781
 782
 783 #define ALL_INIT_DATA_SECTIONS \
 784         ".init.setup", ".init.rodata", ".meminit.rodata", \
 785         ".init.data", ".meminit.data"
 786
 787 #define ALL_PCI_INIT_SECTIONS   \
 788         ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
 789         ".pci_fixup_enable", ".pci_fixup_resume", \
 790         ".pci_fixup_resume_early", ".pci_fixup_suspend"
 791
 792 #define ALL_XXXINIT_SECTIONS ".meminit.*"
 793
 794 #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
 795 #define ALL_EXIT_SECTIONS ".exit.*"
 796
 797 #define DATA_SECTIONS ".data", ".data.rel"
 798 #define TEXT_SECTIONS ".text", ".text.*", ".sched.text", \
 799                 ".kprobes.text", ".cpuidle.text", ".noinstr.text", \
 800                 ".ltext", ".ltext.*"
 801 #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
 802                 ".fixup", ".entry.text", ".exception.text", \
 803                 ".coldtext", ".softirqentry.text"
 804
 805 #define INIT_SECTIONS      ".init.*"
 806
 807 #define ALL_TEXT_SECTIONS  ".init.text", ".meminit.text", ".exit.text", \
 808                 TEXT_SECTIONS, OTHER_TEXT_SECTIONS
 809
 810 enum mismatch {
 811         TEXTDATA_TO_ANY_INIT_EXIT,
 812         XXXINIT_TO_SOME_INIT,
 813         ANY_INIT_TO_ANY_EXIT,
 814         ANY_EXIT_TO_ANY_INIT,
 815         EXTABLE_TO_NON_TEXT,
 816 };
 817
 818 /**
 819  * Describe how to match sections on different criteria:
 820  *
 821  * @fromsec: Array of sections to be matched.
 822  *
 823  * @bad_tosec: Relocations applied to a section in @fromsec to a section in
 824  * this array is forbidden (black-list).  Can be empty.
 825  *
 826  * @good_tosec: Relocations applied to a section in @fromsec must be
 827  * targeting sections in this array (white-list).  Can be empty.
 828  *
 829  * @mismatch: Type of mismatch.
 830  */
 831 struct sectioncheck {
 832         const char *fromsec[20];
 833         const char *bad_tosec[20];
 834         const char *good_tosec[20];
 835         enum mismatch mismatch;
 836 };
 837
 838 static const struct sectioncheck sectioncheck[] = {
 839 /* Do not reference init/exit code/data from
 840  * normal code and data
 841  */
 842 {
 843         .fromsec = { TEXT_SECTIONS, DATA_SECTIONS, NULL },
 844         .bad_tosec = { ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL },
 845         .mismatch = TEXTDATA_TO_ANY_INIT_EXIT,
 846 },
 847 /* Do not reference init code/data from meminit code/data */
 848 {
 849         .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
 850         .bad_tosec = { INIT_SECTIONS, NULL },
 851         .mismatch = XXXINIT_TO_SOME_INIT,
 852 },
 853 /* Do not use exit code/data from init code */
 854 {
 855         .fromsec = { ALL_INIT_SECTIONS, NULL },
 856         .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
 857         .mismatch = ANY_INIT_TO_ANY_EXIT,
 858 },
 859 /* Do not use init code/data from exit code */
 860 {
 861         .fromsec = { ALL_EXIT_SECTIONS, NULL },
 862         .bad_tosec = { ALL_INIT_SECTIONS, NULL },
 863         .mismatch = ANY_EXIT_TO_ANY_INIT,
 864 },
 865 {
 866         .fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
 867         .bad_tosec = { INIT_SECTIONS, NULL },
 868         .mismatch = ANY_INIT_TO_ANY_EXIT,
 869 },
 870 {
 871         .fromsec = { "__ex_table", NULL },
 872         /* If you're adding any new black-listed sections in here, consider
 873          * adding a special 'printer' for them in scripts/check_extable.
 874          */
 875         .bad_tosec = { ".altinstr_replacement", NULL },
 876         .good_tosec = {ALL_TEXT_SECTIONS , NULL},
 877         .mismatch = EXTABLE_TO_NON_TEXT,
 878 }
 879 };
 880
 881 static const struct sectioncheck *section_mismatch(
 882                 const char *fromsec, const char *tosec)
 883 {
 884         int i;
 885
 886         /*
 887          * The target section could be the SHT_NUL section when we're
 888          * handling relocations to un-resolved symbols, trying to match it
 889          * doesn't make much sense and causes build failures on parisc
 890          * architectures.
 891          */
 892         if (*tosec == '\0')
 893                 return NULL;
 894
 895         for (i = 0; i < ARRAY_SIZE(sectioncheck); i++) {
 896                 const struct sectioncheck *check = &sectioncheck[i];
 897
 898                 if (match(fromsec, check->fromsec)) {
 899                         if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
 900                                 return check;
 901                         if (check->good_tosec[0] && !match(tosec, check->good_tosec))
 902                                 return check;
 903                 }
 904         }
 905         return NULL;
 906 }
 907
 908 /**
 909  * Whitelist to allow certain references to pass with no warning.
 910  *
 911  * Pattern 1:
 912  *   If a module parameter is declared __initdata and permissions=0
 913  *   then this is legal despite the warning generated.
 914  *   We cannot see value of permissions here, so just ignore
 915  *   this pattern.
 916  *   The pattern is identified by:
 917  *   tosec   = .init.data
 918  *   fromsec = .data*
 919  *   atsym   =__param*
 920  *
 921  * Pattern 1a:
 922  *   module_param_call() ops can refer to __init set function if permissions=0
 923  *   The pattern is identified by:
 924  *   tosec   = .init.text
 925  *   fromsec = .data*
 926  *   atsym   = __param_ops_*
 927  *
 928  * Pattern 3:
 929  *   Whitelist all references from .head.text to any init section
 930  *
 931  * Pattern 4:
 932  *   Some symbols belong to init section but still it is ok to reference
 933  *   these from non-init sections as these symbols don't have any memory
 934  *   allocated for them and symbol address and value are same. So even
 935  *   if init section is freed, its ok to reference those symbols.
 936  *   For ex. symbols marking the init section boundaries.
 937  *   This pattern is identified by
 938  *   refsymname = __init_begin, _sinittext, _einittext
 939  *
 940  * Pattern 5:
 941  *   GCC may optimize static inlines when fed constant arg(s) resulting
 942  *   in functions like cpumask_empty() -- generating an associated symbol
 943  *   cpumask_empty.constprop.3 that appears in the audit.  If the const that
 944  *   is passed in comes from __init, like say nmi_ipi_mask, we get a
 945  *   meaningless section warning.  May need to add isra symbols too...
 946  *   This pattern is identified by
 947  *   tosec   = init section
 948  *   fromsec = text section
 949  *   refsymname = *.constprop.*
 950  *
 951  **/
 952 static int secref_whitelist(const char *fromsec, const char *fromsym,
 953                             const char *tosec, const char *tosym)
 954 {
 955         /* Check for pattern 1 */
 956         if (match(tosec, PATTERNS(ALL_INIT_DATA_SECTIONS)) &&
 957             match(fromsec, PATTERNS(DATA_SECTIONS)) &&
 958             strstarts(fromsym, "__param"))
 959                 return 0;
 960
 961         /* Check for pattern 1a */
 962         if (strcmp(tosec, ".init.text") == 0 &&
 963             match(fromsec, PATTERNS(DATA_SECTIONS)) &&
 964             strstarts(fromsym, "__param_ops_"))
 965                 return 0;
 966
 967         /* symbols in data sections that may refer to any init/exit sections */
 968         if (match(fromsec, PATTERNS(DATA_SECTIONS)) &&
 969             match(tosec, PATTERNS(ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS)) &&
 970             match(fromsym, PATTERNS("*_ops", "*_probe", "*_console")))
 971                 return 0;
 972
 973         /*
 974          * symbols in data sections must not refer to .exit.*, but there are
 975          * quite a few offenders, so hide these unless for W=1 builds until
 976          * these are fixed.
 977          */
 978         if (!extra_warn &&
 979             match(fromsec, PATTERNS(DATA_SECTIONS)) &&
 980             match(tosec, PATTERNS(ALL_EXIT_SECTIONS)) &&
 981             match(fromsym, PATTERNS("*driver")))
 982                 return 0;
 983
 984         /* Check for pattern 3 */
 985         if (strstarts(fromsec, ".head.text") &&
 986             match(tosec, PATTERNS(ALL_INIT_SECTIONS)))
 987                 return 0;
 988
 989         /* Check for pattern 4 */
 990         if (match(tosym, PATTERNS("__init_begin", "_sinittext", "_einittext")))
 991                 return 0;
 992
 993         /* Check for pattern 5 */
 994         if (match(fromsec, PATTERNS(ALL_TEXT_SECTIONS)) &&
 995             match(tosec, PATTERNS(ALL_INIT_SECTIONS)) &&
 996             match(fromsym, PATTERNS("*.constprop.*")))
 997                 return 0;
 998
 999         return 1;
1000 }
1001
1002 static Elf_Sym *find_fromsym(struct elf_info *elf, Elf_Addr addr,
1003                              unsigned int secndx)
1004 {
1005         return symsearch_find_nearest(elf, addr, secndx, false, ~0);
1006 }
1007
1008 static Elf_Sym *find_tosym(struct elf_info *elf, Elf_Addr addr, Elf_Sym *sym)
1009 {
1010         /* If the supplied symbol has a valid name, return it */
1011         if (is_valid_name(elf, sym))
1012                 return sym;
1013
1014         /*
1015          * Strive to find a better symbol name, but the resulting name may not
1016          * match the symbol referenced in the original code.
1017          */
1018         return symsearch_find_nearest(elf, addr, get_secindex(elf, sym),
1019                                       true, 20);
1020 }
1021
1022 static bool is_executable_section(struct elf_info *elf, unsigned int secndx)
1023 {
1024         if (secndx >= elf->num_sections)
1025                 return false;
1026
1027         return (elf->sechdrs[secndx].sh_flags & SHF_EXECINSTR) != 0;
1028 }
1029
1030 static void default_mismatch_handler(const char *modname, struct elf_info *elf,
1031                                      const struct sectioncheck* const mismatch,
1032                                      Elf_Sym *tsym,
1033                                      unsigned int fsecndx, const char *fromsec, Elf_Addr faddr,
1034                                      const char *tosec, Elf_Addr taddr)
1035 {
1036         Elf_Sym *from;
1037         const char *tosym;
1038         const char *fromsym;
1039
1040         from = find_fromsym(elf, faddr, fsecndx);
1041         fromsym = sym_name(elf, from);
1042
1043         tsym = find_tosym(elf, taddr, tsym);
1044         tosym = sym_name(elf, tsym);
1045
1046         /* check whitelist - we may ignore it */
1047         if (!secref_whitelist(fromsec, fromsym, tosec, tosym))
1048                 return;
1049
1050         sec_mismatch_count++;
1051
1052         warn("%s: section mismatch in reference: %s+0x%x (section: %s) -> %s (section: %s)\n",
1053              modname, fromsym, (unsigned int)(faddr - from->st_value), fromsec, tosym, tosec);
1054
1055         if (mismatch->mismatch == EXTABLE_TO_NON_TEXT) {
1056                 if (match(tosec, mismatch->bad_tosec))
1057                         fatal("The relocation at %s+0x%lx references\n"
1058                               "section \"%s\" which is black-listed.\n"
1059                               "Something is seriously wrong and should be fixed.\n"
1060                               "You might get more information about where this is\n"
1061                               "coming from by using scripts/check_extable.sh %s\n",
1062                               fromsec, (long)faddr, tosec, modname);
1063                 else if (is_executable_section(elf, get_secindex(elf, tsym)))
1064                         warn("The relocation at %s+0x%lx references\n"
1065                              "section \"%s\" which is not in the list of\n"
1066                              "authorized sections.  If you're adding a new section\n"
1067                              "and/or if this reference is valid, add \"%s\" to the\n"
1068                              "list of authorized sections to jump to on fault.\n"
1069                              "This can be achieved by adding \"%s\" to\n"
1070                              "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
1071                              fromsec, (long)faddr, tosec, tosec, tosec);
1072                 else
1073                         error("%s+0x%lx references non-executable section '%s'\n",
1074                               fromsec, (long)faddr, tosec);
1075         }
1076 }
1077
1078 static void check_export_symbol(struct module *mod, struct elf_info *elf,
1079                                 Elf_Addr faddr, const char *secname,
1080                                 Elf_Sym *sym)
1081 {
1082         static const char *prefix = "__export_symbol_";
1083         const char *label_name, *name, *data;
1084         Elf_Sym *label;
1085         struct symbol *s;
1086         bool is_gpl;
1087
1088         label = find_fromsym(elf, faddr, elf->export_symbol_secndx);
1089         label_name = sym_name(elf, label);
1090
1091         if (!strstarts(label_name, prefix)) {
1092                 error("%s: .export_symbol section contains strange symbol '%s'\n",
1093                       mod->name, label_name);
1094                 return;
1095         }
1096
1097         if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
1098             ELF_ST_BIND(sym->st_info) != STB_WEAK) {
1099                 error("%s: local symbol '%s' was exported\n", mod->name,
1100                       label_name + strlen(prefix));
1101                 return;
1102         }
1103
1104         name = sym_name(elf, sym);
1105         if (strcmp(label_name + strlen(prefix), name)) {
1106                 error("%s: .export_symbol section references '%s', but it does not seem to be an export symbol\n",
1107                       mod->name, name);
1108                 return;
1109         }
1110
1111         data = sym_get_data(elf, label);        /* license */
1112         if (!strcmp(data, "GPL")) {
1113                 is_gpl = true;
1114         } else if (!strcmp(data, "")) {
1115                 is_gpl = false;
1116         } else {
1117                 error("%s: unknown license '%s' was specified for '%s'\n",
1118                       mod->name, data, name);
1119                 return;
1120         }
1121
1122         data += strlen(data) + 1;       /* namespace */
1123         s = sym_add_exported(name, mod, is_gpl, data);
1124
1125         /*
1126          * We need to be aware whether we are exporting a function or
1127          * a data on some architectures.
1128          */
1129         s->is_func = (ELF_ST_TYPE(sym->st_info) == STT_FUNC);
1130
1131         /*
1132          * For parisc64, symbols prefixed $$ from the library have the symbol type
1133          * STT_LOPROC. They should be handled as functions too.
1134          */
1135         if (elf->hdr->e_ident[EI_CLASS] == ELFCLASS64 &&
1136             elf->hdr->e_machine == EM_PARISC &&
1137             ELF_ST_TYPE(sym->st_info) == STT_LOPROC)
1138                 s->is_func = true;
1139
1140         if (match(secname, PATTERNS(ALL_INIT_SECTIONS)))
1141                 warn("%s: %s: EXPORT_SYMBOL used for init symbol. Remove __init or EXPORT_SYMBOL.\n",
1142                      mod->name, name);
1143         else if (match(secname, PATTERNS(ALL_EXIT_SECTIONS)))
1144                 warn("%s: %s: EXPORT_SYMBOL used for exit symbol. Remove __exit or EXPORT_SYMBOL.\n",
1145                      mod->name, name);
1146 }
1147
1148 static void check_section_mismatch(struct module *mod, struct elf_info *elf,
1149                                    Elf_Sym *sym,
1150                                    unsigned int fsecndx, const char *fromsec,
1151                                    Elf_Addr faddr, Elf_Addr taddr)
1152 {
1153         const char *tosec = sec_name(elf, get_secindex(elf, sym));
1154         const struct sectioncheck *mismatch;
1155
1156         if (module_enabled && elf->export_symbol_secndx == fsecndx) {
1157                 check_export_symbol(mod, elf, faddr, tosec, sym);
1158                 return;
1159         }
1160
1161         mismatch = section_mismatch(fromsec, tosec);
1162         if (!mismatch)
1163                 return;
1164
1165         default_mismatch_handler(mod->name, elf, mismatch, sym,
1166                                  fsecndx, fromsec, faddr,
1167                                  tosec, taddr);
1168 }
1169
1170 static Elf_Addr addend_386_rel(uint32_t *location, unsigned int r_type)
1171 {
1172         switch (r_type) {
1173         case R_386_32:
1174                 return TO_NATIVE(*location);
1175         case R_386_PC32:
1176                 return TO_NATIVE(*location) + 4;
1177         }
1178
1179         return (Elf_Addr)(-1);
1180 }
1181
1182 #ifndef R_ARM_CALL
1183 #define R_ARM_CALL      28
1184 #endif
1185 #ifndef R_ARM_JUMP24
1186 #define R_ARM_JUMP24    29
1187 #endif
1188
1189 #ifndef R_ARM_THM_CALL
1190 #define R_ARM_THM_CALL          10
1191 #endif
1192 #ifndef R_ARM_THM_JUMP24
1193 #define R_ARM_THM_JUMP24        30
1194 #endif
1195
1196 #ifndef R_ARM_MOVW_ABS_NC
1197 #define R_ARM_MOVW_ABS_NC       43
1198 #endif
1199
1200 #ifndef R_ARM_MOVT_ABS
1201 #define R_ARM_MOVT_ABS          44
1202 #endif
1203
1204 #ifndef R_ARM_THM_MOVW_ABS_NC
1205 #define R_ARM_THM_MOVW_ABS_NC   47
1206 #endif
1207
1208 #ifndef R_ARM_THM_MOVT_ABS
1209 #define R_ARM_THM_MOVT_ABS      48
1210 #endif
1211
1212 #ifndef R_ARM_THM_JUMP19
1213 #define R_ARM_THM_JUMP19        51
1214 #endif
1215
1216 static int32_t sign_extend32(int32_t value, int index)
1217 {
1218         uint8_t shift = 31 - index;
1219
1220         return (int32_t)(value << shift) >> shift;
1221 }
1222
1223 static Elf_Addr addend_arm_rel(void *loc, Elf_Sym *sym, unsigned int r_type)
1224 {
1225         uint32_t inst, upper, lower, sign, j1, j2;
1226         int32_t offset;
1227
1228         switch (r_type) {
1229         case R_ARM_ABS32:
1230         case R_ARM_REL32:
1231                 inst = TO_NATIVE(*(uint32_t *)loc);
1232                 return inst + sym->st_value;
1233         case R_ARM_MOVW_ABS_NC:
1234         case R_ARM_MOVT_ABS:
1235                 inst = TO_NATIVE(*(uint32_t *)loc);
1236                 offset = sign_extend32(((inst & 0xf0000) >> 4) | (inst & 0xfff),
1237                                        15);
1238                 return offset + sym->st_value;
1239         case R_ARM_PC24:
1240         case R_ARM_CALL:
1241         case R_ARM_JUMP24:
1242                 inst = TO_NATIVE(*(uint32_t *)loc);
1243                 offset = sign_extend32((inst & 0x00ffffff) << 2, 25);
1244                 return offset + sym->st_value + 8;
1245         case R_ARM_THM_MOVW_ABS_NC:
1246         case R_ARM_THM_MOVT_ABS:
1247                 upper = TO_NATIVE(*(uint16_t *)loc);
1248                 lower = TO_NATIVE(*((uint16_t *)loc + 1));
1249                 offset = sign_extend32(((upper & 0x000f) << 12) |
1250                                        ((upper & 0x0400) << 1) |
1251                                        ((lower & 0x7000) >> 4) |
1252                                        (lower & 0x00ff),
1253                                        15);
1254                 return offset + sym->st_value;
1255         case R_ARM_THM_JUMP19:
1256                 /*
1257                  * Encoding T3:
1258                  * S     = upper[10]
1259                  * imm6  = upper[5:0]
1260                  * J1    = lower[13]
1261                  * J2    = lower[11]
1262                  * imm11 = lower[10:0]
1263                  * imm32 = SignExtend(S:J2:J1:imm6:imm11:'0')
1264                  */
1265                 upper = TO_NATIVE(*(uint16_t *)loc);
1266                 lower = TO_NATIVE(*((uint16_t *)loc + 1));
1267
1268                 sign = (upper >> 10) & 1;
1269                 j1 = (lower >> 13) & 1;
1270                 j2 = (lower >> 11) & 1;
1271                 offset = sign_extend32((sign << 20) | (j2 << 19) | (j1 << 18) |
1272                                        ((upper & 0x03f) << 12) |
1273                                        ((lower & 0x07ff) << 1),
1274                                        20);
1275                 return offset + sym->st_value + 4;
1276         case R_ARM_THM_CALL:
1277         case R_ARM_THM_JUMP24:
1278                 /*
1279                  * Encoding T4:
1280                  * S     = upper[10]
1281                  * imm10 = upper[9:0]
1282                  * J1    = lower[13]
1283                  * J2    = lower[11]
1284                  * imm11 = lower[10:0]
1285                  * I1    = NOT(J1 XOR S)
1286                  * I2    = NOT(J2 XOR S)
1287                  * imm32 = SignExtend(S:I1:I2:imm10:imm11:'0')
1288                  */
1289                 upper = TO_NATIVE(*(uint16_t *)loc);
1290                 lower = TO_NATIVE(*((uint16_t *)loc + 1));
1291
1292                 sign = (upper >> 10) & 1;
1293                 j1 = (lower >> 13) & 1;
1294                 j2 = (lower >> 11) & 1;
1295                 offset = sign_extend32((sign << 24) |
1296                                        ((~(j1 ^ sign) & 1) << 23) |
1297                                        ((~(j2 ^ sign) & 1) << 22) |
1298                                        ((upper & 0x03ff) << 12) |
1299                                        ((lower & 0x07ff) << 1),
1300                                        24);
1301                 return offset + sym->st_value + 4;
1302         }
1303
1304         return (Elf_Addr)(-1);
1305 }
1306
1307 static Elf_Addr addend_mips_rel(uint32_t *location, unsigned int r_type)
1308 {
1309         uint32_t inst;
1310
1311         inst = TO_NATIVE(*location);
1312         switch (r_type) {
1313         case R_MIPS_LO16:
1314                 return inst & 0xffff;
1315         case R_MIPS_26:
1316                 return (inst & 0x03ffffff) << 2;
1317         case R_MIPS_32:
1318                 return inst;
1319         }
1320         return (Elf_Addr)(-1);
1321 }
1322
1323 #ifndef EM_RISCV
1324 #define EM_RISCV                243
1325 #endif
1326
1327 #ifndef R_RISCV_SUB32
1328 #define R_RISCV_SUB32           39
1329 #endif
1330
1331 #ifndef EM_LOONGARCH
1332 #define EM_LOONGARCH            258
1333 #endif
1334
1335 #ifndef R_LARCH_SUB32
1336 #define R_LARCH_SUB32           55
1337 #endif
1338
1339 #ifndef R_LARCH_RELAX
1340 #define R_LARCH_RELAX           100
1341 #endif
1342
1343 #ifndef R_LARCH_ALIGN
1344 #define R_LARCH_ALIGN           102
1345 #endif
1346
1347 static void get_rel_type_and_sym(struct elf_info *elf, uint64_t r_info,
1348                                  unsigned int *r_type, unsigned int *r_sym)
1349 {
1350         typedef struct {
1351                 Elf64_Word    r_sym;    /* Symbol index */
1352                 unsigned char r_ssym;   /* Special symbol for 2nd relocation */
1353                 unsigned char r_type3;  /* 3rd relocation type */
1354                 unsigned char r_type2;  /* 2nd relocation type */
1355                 unsigned char r_type;   /* 1st relocation type */
1356         } Elf64_Mips_R_Info;
1357
1358         bool is_64bit = (elf->hdr->e_ident[EI_CLASS] == ELFCLASS64);
1359
1360         if (elf->hdr->e_machine == EM_MIPS && is_64bit) {
1361                 Elf64_Mips_R_Info *mips64_r_info = (void *)&r_info;
1362
1363                 *r_type = mips64_r_info->r_type;
1364                 *r_sym = TO_NATIVE(mips64_r_info->r_sym);
1365                 return;
1366         }
1367
1368         if (is_64bit)
1369                 r_info = TO_NATIVE((Elf64_Xword)r_info);
1370         else
1371                 r_info = TO_NATIVE((Elf32_Word)r_info);
1372
1373         *r_type = ELF_R_TYPE(r_info);
1374         *r_sym = ELF_R_SYM(r_info);
1375 }
1376
1377 static void section_rela(struct module *mod, struct elf_info *elf,
1378                          unsigned int fsecndx, const char *fromsec,
1379                          const Elf_Rela *start, const Elf_Rela *stop)
1380 {
1381         const Elf_Rela *rela;
1382
1383         for (rela = start; rela < stop; rela++) {
1384                 Elf_Sym *tsym;
1385                 Elf_Addr taddr, r_offset;
1386                 unsigned int r_type, r_sym;
1387
1388                 r_offset = TO_NATIVE(rela->r_offset);
1389                 get_rel_type_and_sym(elf, rela->r_info, &r_type, &r_sym);
1390
1391                 tsym = elf->symtab_start + r_sym;
1392                 taddr = tsym->st_value + TO_NATIVE(rela->r_addend);
1393
1394                 switch (elf->hdr->e_machine) {
1395                 case EM_RISCV:
1396                         if (!strcmp("__ex_table", fromsec) &&
1397                             r_type == R_RISCV_SUB32)
1398                                 continue;
1399                         break;
1400                 case EM_LOONGARCH:
1401                         switch (r_type) {
1402                         case R_LARCH_SUB32:
1403                                 if (!strcmp("__ex_table", fromsec))
1404                                         continue;
1405                                 break;
1406                         case R_LARCH_RELAX:
1407                         case R_LARCH_ALIGN:
1408                                 /* These relocs do not refer to symbols */
1409                                 continue;
1410                         }
1411                         break;
1412                 }
1413
1414                 check_section_mismatch(mod, elf, tsym,
1415                                        fsecndx, fromsec, r_offset, taddr);
1416         }
1417 }
1418
1419 static void section_rel(struct module *mod, struct elf_info *elf,
1420                         unsigned int fsecndx, const char *fromsec,
1421                         const Elf_Rel *start, const Elf_Rel *stop)
1422 {
1423         const Elf_Rel *rel;
1424
1425         for (rel = start; rel < stop; rel++) {
1426                 Elf_Sym *tsym;
1427                 Elf_Addr taddr, r_offset;
1428                 unsigned int r_type, r_sym;
1429                 void *loc;
1430
1431                 r_offset = TO_NATIVE(rel->r_offset);
1432                 get_rel_type_and_sym(elf, rel->r_info, &r_type, &r_sym);
1433
1434                 loc = sym_get_data_by_offset(elf, fsecndx, r_offset);
1435                 tsym = elf->symtab_start + r_sym;
1436
1437                 switch (elf->hdr->e_machine) {
1438                 case EM_386:
1439                         taddr = addend_386_rel(loc, r_type);
1440                         break;
1441                 case EM_ARM:
1442                         taddr = addend_arm_rel(loc, tsym, r_type);
1443                         break;
1444                 case EM_MIPS:
1445                         taddr = addend_mips_rel(loc, r_type);
1446                         break;
1447                 default:
1448                         fatal("Please add code to calculate addend for this architecture\n");
1449                 }
1450
1451                 check_section_mismatch(mod, elf, tsym,
1452                                        fsecndx, fromsec, r_offset, taddr);
1453         }
1454 }
1455
1456 /**
1457  * A module includes a number of sections that are discarded
1458  * either when loaded or when used as built-in.
1459  * For loaded modules all functions marked __init and all data
1460  * marked __initdata will be discarded when the module has been initialized.
1461  * Likewise for modules used built-in the sections marked __exit
1462  * are discarded because __exit marked function are supposed to be called
1463  * only when a module is unloaded which never happens for built-in modules.
1464  * The check_sec_ref() function traverses all relocation records
1465  * to find all references to a section that reference a section that will
1466  * be discarded and warns about it.
1467  **/
1468 static void check_sec_ref(struct module *mod, struct elf_info *elf)
1469 {
1470         int i;
1471
1472         /* Walk through all sections */
1473         for (i = 0; i < elf->num_sections; i++) {
1474                 Elf_Shdr *sechdr = &elf->sechdrs[i];
1475
1476                 check_section(mod->name, elf, sechdr);
1477                 /* We want to process only relocation sections and not .init */
1478                 if (sechdr->sh_type == SHT_REL || sechdr->sh_type == SHT_RELA) {
1479                         /* section to which the relocation applies */
1480                         unsigned int secndx = sechdr->sh_info;
1481                         const char *secname = sec_name(elf, secndx);
1482                         const void *start, *stop;
1483
1484                         /* If the section is known good, skip it */
1485                         if (match(secname, section_white_list))
1486                                 continue;
1487
1488                         start = sym_get_data_by_offset(elf, i, 0);
1489                         stop = start + sechdr->sh_size;
1490
1491                         if (sechdr->sh_type == SHT_RELA)
1492                                 section_rela(mod, elf, secndx, secname,
1493                                              start, stop);
1494                         else
1495                                 section_rel(mod, elf, secndx, secname,
1496                                             start, stop);
1497                 }
1498         }
1499 }
1500
1501 static char *remove_dot(char *s)
1502 {
1503         size_t n = strcspn(s, ".");
1504
1505         if (n && s[n]) {
1506                 size_t m = strspn(s + n + 1, "0123456789");
1507                 if (m && (s[n + m + 1] == '.' || s[n + m + 1] == 0))
1508                         s[n] = 0;
1509         }
1510         return s;
1511 }
1512
1513 /*
1514  * The CRCs are recorded in .*.cmd files in the form of:
1515  * #SYMVER <name> <crc>
1516  */
1517 static void extract_crcs_for_object(const char *object, struct module *mod)
1518 {
1519         char cmd_file[PATH_MAX];
1520         char *buf, *p;
1521         const char *base;
1522         int dirlen, ret;
1523
1524         base = strrchr(object, '/');
1525         if (base) {
1526                 base++;
1527                 dirlen = base - object;
1528         } else {
1529                 dirlen = 0;
1530                 base = object;
1531         }
1532
1533         ret = snprintf(cmd_file, sizeof(cmd_file), "%.*s.%s.cmd",
1534                        dirlen, object, base);
1535         if (ret >= sizeof(cmd_file)) {
1536                 error("%s: too long path was truncated\n", cmd_file);
1537                 return;
1538         }
1539
1540         buf = read_text_file(cmd_file);
1541         p = buf;
1542
1543         while ((p = strstr(p, "\n#SYMVER "))) {
1544                 char *name;
1545                 size_t namelen;
1546                 unsigned int crc;
1547                 struct symbol *sym;
1548
1549                 name = p + strlen("\n#SYMVER ");
1550
1551                 p = strchr(name, ' ');
1552                 if (!p)
1553                         break;
1554
1555                 namelen = p - name;
1556                 p++;
1557
1558                 if (!isdigit(*p))
1559                         continue;       /* skip this line */
1560
1561                 crc = strtoul(p, &p, 0);
1562                 if (*p != '\n')
1563                         continue;       /* skip this line */
1564
1565                 name[namelen] = '\0';
1566
1567                 /*
1568                  * sym_find_with_module() may return NULL here.
1569                  * It typically occurs when CONFIG_TRIM_UNUSED_KSYMS=y.
1570                  * Since commit e1327a127703, genksyms calculates CRCs of all
1571                  * symbols, including trimmed ones. Ignore orphan CRCs.
1572                  */
1573                 sym = sym_find_with_module(name, mod);
1574                 if (sym)
1575                         sym_set_crc(sym, crc);
1576         }
1577
1578         free(buf);
1579 }
1580
1581 /*
1582  * The symbol versions (CRC) are recorded in the .*.cmd files.
1583  * Parse them to retrieve CRCs for the current module.
1584  */
1585 static void mod_set_crcs(struct module *mod)
1586 {
1587         char objlist[PATH_MAX];
1588         char *buf, *p, *obj;
1589         int ret;
1590
1591         if (mod->is_vmlinux) {
1592                 strcpy(objlist, ".vmlinux.objs");
1593         } else {
1594                 /* objects for a module are listed in the *.mod file. */
1595                 ret = snprintf(objlist, sizeof(objlist), "%s.mod", mod->name);
1596                 if (ret >= sizeof(objlist)) {
1597                         error("%s: too long path was truncated\n", objlist);
1598                         return;
1599                 }
1600         }
1601
1602         buf = read_text_file(objlist);
1603         p = buf;
1604
1605         while ((obj = strsep(&p, "\n")) && obj[0])
1606                 extract_crcs_for_object(obj, mod);
1607
1608         free(buf);
1609 }
1610
1611 static void read_symbols(const char *modname)
1612 {
1613         const char *symname;
1614         char *version;
1615         char *license;
1616         char *namespace;
1617         struct module *mod;
1618         struct elf_info info = { };
1619         Elf_Sym *sym;
1620
1621         if (!parse_elf(&info, modname))
1622                 return;
1623
1624         if (!strends(modname, ".o")) {
1625                 error("%s: filename must be suffixed with .o\n", modname);
1626                 return;
1627         }
1628
1629         /* strip trailing .o */
1630         mod = new_module(modname, strlen(modname) - strlen(".o"));
1631
1632         if (!mod->is_vmlinux) {
1633                 license = get_modinfo(&info, "license");
1634                 if (!license)
1635                         error("missing MODULE_LICENSE() in %s\n", modname);
1636                 while (license) {
1637                         if (!license_is_gpl_compatible(license)) {
1638                                 mod->is_gpl_compatible = false;
1639                                 break;
1640                         }
1641                         license = get_next_modinfo(&info, "license", license);
1642                 }
1643
1644                 namespace = get_modinfo(&info, "import_ns");
1645                 while (namespace) {
1646                         add_namespace(&mod->imported_namespaces, namespace);
1647                         namespace = get_next_modinfo(&info, "import_ns",
1648                                                      namespace);
1649                 }
1650         }
1651
1652         if (extra_warn && !get_modinfo(&info, "description"))
1653                 warn("missing MODULE_DESCRIPTION() in %s\n", modname);
1654         for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1655                 symname = remove_dot(info.strtab + sym->st_name);
1656
1657                 handle_symbol(mod, &info, sym, symname);
1658                 handle_moddevtable(mod, &info, sym, symname);
1659         }
1660
1661         check_sec_ref(mod, &info);
1662
1663         if (!mod->is_vmlinux) {
1664                 version = get_modinfo(&info, "version");
1665                 if (version || all_versions)
1666                         get_src_version(mod->name, mod->srcversion,
1667                                         sizeof(mod->srcversion) - 1);
1668         }
1669
1670         parse_elf_finish(&info);
1671
1672         if (modversions) {
1673                 /*
1674                  * Our trick to get versioning for module struct etc. - it's
1675                  * never passed as an argument to an exported function, so
1676                  * the automatic versioning doesn't pick it up, but it's really
1677                  * important anyhow.
1678                  */
1679                 sym_add_unresolved("module_layout", mod, false);
1680
1681                 mod_set_crcs(mod);
1682         }
1683 }
1684
1685 static void read_symbols_from_files(const char *filename)
1686 {
1687         FILE *in = stdin;
1688         char fname[PATH_MAX];
1689
1690         in = fopen(filename, "r");
1691         if (!in)
1692                 fatal("Can't open filenames file %s: %m", filename);
1693
1694         while (fgets(fname, PATH_MAX, in) != NULL) {
1695                 if (strends(fname, "\n"))
1696                         fname[strlen(fname)-1] = '\0';
1697                 read_symbols(fname);
1698         }
1699
1700         fclose(in);
1701 }
1702
1703 #define SZ 500
1704
1705 /* We first write the generated file into memory using the
1706  * following helper, then compare to the file on disk and
1707  * only update the later if anything changed */
1708
1709 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
1710                                                       const char *fmt, ...)
1711 {
1712         char tmp[SZ];
1713         int len;
1714         va_list ap;
1715
1716         va_start(ap, fmt);
1717         len = vsnprintf(tmp, SZ, fmt, ap);
1718         buf_write(buf, tmp, len);
1719         va_end(ap);
1720 }
1721
1722 void buf_write(struct buffer *buf, const char *s, int len)
1723 {
1724         if (buf->size - buf->pos < len) {
1725                 buf->size += len + SZ;
1726                 buf->p = NOFAIL(realloc(buf->p, buf->size));
1727         }
1728         strncpy(buf->p + buf->pos, s, len);
1729         buf->pos += len;
1730 }
1731
1732 static void check_exports(struct module *mod)
1733 {
1734         struct symbol *s, *exp;
1735
1736         list_for_each_entry(s, &mod->unresolved_symbols, list) {
1737                 const char *basename;
1738                 exp = find_symbol(s->name);
1739                 if (!exp) {
1740                         if (!s->weak && nr_unresolved++ < MAX_UNRESOLVED_REPORTS)
1741                                 modpost_log(warn_unresolved ? LOG_WARN : LOG_ERROR,
1742                                             "\"%s\" [%s.ko] undefined!\n",
1743                                             s->name, mod->name);
1744                         continue;
1745                 }
1746                 if (exp->module == mod) {
1747                         error("\"%s\" [%s.ko] was exported without definition\n",
1748                               s->name, mod->name);
1749                         continue;
1750                 }
1751
1752                 exp->used = true;
1753                 s->module = exp->module;
1754                 s->crc_valid = exp->crc_valid;
1755                 s->crc = exp->crc;
1756
1757                 basename = strrchr(mod->name, '/');
1758                 if (basename)
1759                         basename++;
1760                 else
1761                         basename = mod->name;
1762
1763                 if (!contains_namespace(&mod->imported_namespaces, exp->namespace)) {
1764                         modpost_log(allow_missing_ns_imports ? LOG_WARN : LOG_ERROR,
1765                                     "module %s uses symbol %s from namespace %s, but does not import it.\n",
1766                                     basename, exp->name, exp->namespace);
1767                         add_namespace(&mod->missing_namespaces, exp->namespace);
1768                 }
1769
1770                 if (!mod->is_gpl_compatible && exp->is_gpl_only)
1771                         error("GPL-incompatible module %s.ko uses GPL-only symbol '%s'\n",
1772                               basename, exp->name);
1773         }
1774 }
1775
1776 static void handle_white_list_exports(const char *white_list)
1777 {
1778         char *buf, *p, *name;
1779
1780         buf = read_text_file(white_list);
1781         p = buf;
1782
1783         while ((name = strsep(&p, "\n"))) {
1784                 struct symbol *sym = find_symbol(name);
1785
1786                 if (sym)
1787                         sym->used = true;
1788         }
1789
1790         free(buf);
1791 }
1792
1793 static void check_modname_len(struct module *mod)
1794 {
1795         const char *mod_name;
1796
1797         mod_name = strrchr(mod->name, '/');
1798         if (mod_name == NULL)
1799                 mod_name = mod->name;
1800         else
1801                 mod_name++;
1802         if (strlen(mod_name) >= MODULE_NAME_LEN)
1803                 error("module name is too long [%s.ko]\n", mod->name);
1804 }
1805
1806 /**
1807  * Header for the generated file
1808  **/
1809 static void add_header(struct buffer *b, struct module *mod)
1810 {
1811         buf_printf(b, "#include <linux/module.h>\n");
1812         /*
1813          * Include build-salt.h after module.h in order to
1814          * inherit the definitions.
1815          */
1816         buf_printf(b, "#define INCLUDE_VERMAGIC\n");
1817         buf_printf(b, "#include <linux/build-salt.h>\n");
1818         buf_printf(b, "#include <linux/elfnote-lto.h>\n");
1819         buf_printf(b, "#include <linux/export-internal.h>\n");
1820         buf_printf(b, "#include <linux/vermagic.h>\n");
1821         buf_printf(b, "#include <linux/compiler.h>\n");
1822         buf_printf(b, "\n");
1823         buf_printf(b, "#ifdef CONFIG_UNWINDER_ORC\n");
1824         buf_printf(b, "#include <asm/orc_header.h>\n");
1825         buf_printf(b, "ORC_HEADER;\n");
1826         buf_printf(b, "#endif\n");
1827         buf_printf(b, "\n");
1828         buf_printf(b, "BUILD_SALT;\n");
1829         buf_printf(b, "BUILD_LTO_INFO;\n");
1830         buf_printf(b, "\n");
1831         buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
1832         buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n");
1833         buf_printf(b, "\n");
1834         buf_printf(b, "__visible struct module __this_module\n");
1835         buf_printf(b, "__section(\".gnu.linkonce.this_module\") = {\n");
1836         buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
1837         if (mod->has_init)
1838                 buf_printf(b, "\t.init = init_module,\n");
1839         if (mod->has_cleanup)
1840                 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
1841                               "\t.exit = cleanup_module,\n"
1842                               "#endif\n");
1843         buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
1844         buf_printf(b, "};\n");
1845
1846         if (!external_module)
1847                 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
1848
1849         buf_printf(b,
1850                    "\n"
1851                    "#ifdef CONFIG_RETPOLINE\n"
1852                    "MODULE_INFO(retpoline, \"Y\");\n"
1853                    "#endif\n");
1854
1855         if (strstarts(mod->name, "drivers/staging"))
1856                 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
1857
1858         if (strstarts(mod->name, "tools/testing"))
1859                 buf_printf(b, "\nMODULE_INFO(test, \"Y\");\n");
1860 }
1861
1862 static void add_exported_symbols(struct buffer *buf, struct module *mod)
1863 {
1864         struct symbol *sym;
1865
1866         /* generate struct for exported symbols */
1867         buf_printf(buf, "\n");
1868         list_for_each_entry(sym, &mod->exported_symbols, list) {
1869                 if (trim_unused_exports && !sym->used)
1870                         continue;
1871
1872                 buf_printf(buf, "KSYMTAB_%s(%s, \"%s\", \"%s\");\n",
1873                            sym->is_func ? "FUNC" : "DATA", sym->name,
1874                            sym->is_gpl_only ? "_gpl" : "", sym->namespace);
1875         }
1876
1877         if (!modversions)
1878                 return;
1879
1880         /* record CRCs for exported symbols */
1881         buf_printf(buf, "\n");
1882         list_for_each_entry(sym, &mod->exported_symbols, list) {
1883                 if (trim_unused_exports && !sym->used)
1884                         continue;
1885
1886                 if (!sym->crc_valid)
1887                         warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n"
1888                              "Is \"%s\" prototyped in <asm/asm-prototypes.h>?\n",
1889                              sym->name, mod->name, mod->is_vmlinux ? "" : ".ko",
1890                              sym->name);
1891
1892                 buf_printf(buf, "SYMBOL_CRC(%s, 0x%08x, \"%s\");\n",
1893                            sym->name, sym->crc, sym->is_gpl_only ? "_gpl" : "");
1894         }
1895 }
1896
1897 /**
1898  * Record CRCs for unresolved symbols
1899  **/
1900 static void add_versions(struct buffer *b, struct module *mod)
1901 {
1902         struct symbol *s;
1903
1904         if (!modversions)
1905                 return;
1906
1907         buf_printf(b, "\n");
1908         buf_printf(b, "static const struct modversion_info ____versions[]\n");
1909         buf_printf(b, "__used __section(\"__versions\") = {\n");
1910
1911         list_for_each_entry(s, &mod->unresolved_symbols, list) {
1912                 if (!s->module)
1913                         continue;
1914                 if (!s->crc_valid) {
1915                         warn("\"%s\" [%s.ko] has no CRC!\n",
1916                                 s->name, mod->name);
1917                         continue;
1918                 }
1919                 if (strlen(s->name) >= MODULE_NAME_LEN) {
1920                         error("too long symbol \"%s\" [%s.ko]\n",
1921                               s->name, mod->name);
1922                         break;
1923                 }
1924                 buf_printf(b, "\t{ %#8x, \"%s\" },\n",
1925                            s->crc, s->name);
1926         }
1927
1928         buf_printf(b, "};\n");
1929 }
1930
1931 static void add_depends(struct buffer *b, struct module *mod)
1932 {
1933         struct symbol *s;
1934         int first = 1;
1935
1936         /* Clear ->seen flag of modules that own symbols needed by this. */
1937         list_for_each_entry(s, &mod->unresolved_symbols, list) {
1938                 if (s->module)
1939                         s->module->seen = s->module->is_vmlinux;
1940         }
1941
1942         buf_printf(b, "\n");
1943         buf_printf(b, "MODULE_INFO(depends, \"");
1944         list_for_each_entry(s, &mod->unresolved_symbols, list) {
1945                 const char *p;
1946                 if (!s->module)
1947                         continue;
1948
1949                 if (s->module->seen)
1950                         continue;
1951
1952                 s->module->seen = true;
1953                 p = strrchr(s->module->name, '/');
1954                 if (p)
1955                         p++;
1956                 else
1957                         p = s->module->name;
1958                 buf_printf(b, "%s%s", first ? "" : ",", p);
1959                 first = 0;
1960         }
1961         buf_printf(b, "\");\n");
1962 }
1963
1964 static void add_srcversion(struct buffer *b, struct module *mod)
1965 {
1966         if (mod->srcversion[0]) {
1967                 buf_printf(b, "\n");
1968                 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
1969                            mod->srcversion);
1970         }
1971 }
1972
1973 static void write_buf(struct buffer *b, const char *fname)
1974 {
1975         FILE *file;
1976
1977         if (error_occurred)
1978                 return;
1979
1980         file = fopen(fname, "w");
1981         if (!file) {
1982                 perror(fname);
1983                 exit(1);
1984         }
1985         if (fwrite(b->p, 1, b->pos, file) != b->pos) {
1986                 perror(fname);
1987                 exit(1);
1988         }
1989         if (fclose(file) != 0) {
1990                 perror(fname);
1991                 exit(1);
1992         }
1993 }
1994
1995 static void write_if_changed(struct buffer *b, const char *fname)
1996 {
1997         char *tmp;
1998         FILE *file;
1999         struct stat st;
2000
2001         file = fopen(fname, "r");
2002         if (!file)
2003                 goto write;
2004
2005         if (fstat(fileno(file), &st) < 0)
2006                 goto close_write;
2007
2008         if (st.st_size != b->pos)
2009                 goto close_write;
2010
2011         tmp = NOFAIL(malloc(b->pos));
2012         if (fread(tmp, 1, b->pos, file) != b->pos)
2013                 goto free_write;
2014
2015         if (memcmp(tmp, b->p, b->pos) != 0)
2016                 goto free_write;
2017
2018         free(tmp);
2019         fclose(file);
2020         return;
2021
2022  free_write:
2023         free(tmp);
2024  close_write:
2025         fclose(file);
2026  write:
2027         write_buf(b, fname);
2028 }
2029
2030 static void write_vmlinux_export_c_file(struct module *mod)
2031 {
2032         struct buffer buf = { };
2033
2034         buf_printf(&buf,
2035                    "#include <linux/export-internal.h>\n");
2036
2037         add_exported_symbols(&buf, mod);
2038         write_if_changed(&buf, ".vmlinux.export.c");
2039         free(buf.p);
2040 }
2041
2042 /* do sanity checks, and generate *.mod.c file */
2043 static void write_mod_c_file(struct module *mod)
2044 {
2045         struct buffer buf = { };
2046         char fname[PATH_MAX];
2047         int ret;
2048
2049         add_header(&buf, mod);
2050         add_exported_symbols(&buf, mod);
2051         add_versions(&buf, mod);
2052         add_depends(&buf, mod);
2053         add_moddevtable(&buf, mod);
2054         add_srcversion(&buf, mod);
2055
2056         ret = snprintf(fname, sizeof(fname), "%s.mod.c", mod->name);
2057         if (ret >= sizeof(fname)) {
2058                 error("%s: too long path was truncated\n", fname);
2059                 goto free;
2060         }
2061
2062         write_if_changed(&buf, fname);
2063
2064 free:
2065         free(buf.p);
2066 }
2067
2068 /* parse Module.symvers file. line format:
2069  * 0x12345678<tab>symbol<tab>module<tab>export<tab>namespace
2070  **/
2071 static void read_dump(const char *fname)
2072 {
2073         char *buf, *pos, *line;
2074
2075         buf = read_text_file(fname);
2076         if (!buf)
2077                 /* No symbol versions, silently ignore */
2078                 return;
2079
2080         pos = buf;
2081
2082         while ((line = get_line(&pos))) {
2083                 char *symname, *namespace, *modname, *d, *export;
2084                 unsigned int crc;
2085                 struct module *mod;
2086                 struct symbol *s;
2087                 bool gpl_only;
2088
2089                 if (!(symname = strchr(line, '\t')))
2090                         goto fail;
2091                 *symname++ = '\0';
2092                 if (!(modname = strchr(symname, '\t')))
2093                         goto fail;
2094                 *modname++ = '\0';
2095                 if (!(export = strchr(modname, '\t')))
2096                         goto fail;
2097                 *export++ = '\0';
2098                 if (!(namespace = strchr(export, '\t')))
2099                         goto fail;
2100                 *namespace++ = '\0';
2101
2102                 crc = strtoul(line, &d, 16);
2103                 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2104                         goto fail;
2105
2106                 if (!strcmp(export, "EXPORT_SYMBOL_GPL")) {
2107                         gpl_only = true;
2108                 } else if (!strcmp(export, "EXPORT_SYMBOL")) {
2109                         gpl_only = false;
2110                 } else {
2111                         error("%s: unknown license %s. skip", symname, export);
2112                         continue;
2113                 }
2114
2115                 mod = find_module(modname);
2116                 if (!mod) {
2117                         mod = new_module(modname, strlen(modname));
2118                         mod->from_dump = true;
2119                 }
2120                 s = sym_add_exported(symname, mod, gpl_only, namespace);
2121                 sym_set_crc(s, crc);
2122         }
2123         free(buf);
2124         return;
2125 fail:
2126         free(buf);
2127         fatal("parse error in symbol dump file\n");
2128 }
2129
2130 static void write_dump(const char *fname)
2131 {
2132         struct buffer buf = { };
2133         struct module *mod;
2134         struct symbol *sym;
2135
2136         list_for_each_entry(mod, &modules, list) {
2137                 if (mod->from_dump)
2138                         continue;
2139                 list_for_each_entry(sym, &mod->exported_symbols, list) {
2140                         if (trim_unused_exports && !sym->used)
2141                                 continue;
2142
2143                         buf_printf(&buf, "0x%08x\t%s\t%s\tEXPORT_SYMBOL%s\t%s\n",
2144                                    sym->crc, sym->name, mod->name,
2145                                    sym->is_gpl_only ? "_GPL" : "",
2146                                    sym->namespace);
2147                 }
2148         }
2149         write_buf(&buf, fname);
2150         free(buf.p);
2151 }
2152
2153 static void write_namespace_deps_files(const char *fname)
2154 {
2155         struct module *mod;
2156         struct namespace_list *ns;
2157         struct buffer ns_deps_buf = {};
2158
2159         list_for_each_entry(mod, &modules, list) {
2160
2161                 if (mod->from_dump || list_empty(&mod->missing_namespaces))
2162                         continue;
2163
2164                 buf_printf(&ns_deps_buf, "%s.ko:", mod->name);
2165
2166                 list_for_each_entry(ns, &mod->missing_namespaces, list)
2167                         buf_printf(&ns_deps_buf, " %s", ns->namespace);
2168
2169                 buf_printf(&ns_deps_buf, "\n");
2170         }
2171
2172         write_if_changed(&ns_deps_buf, fname);
2173         free(ns_deps_buf.p);
2174 }
2175
2176 struct dump_list {
2177         struct list_head list;
2178         const char *file;
2179 };
2180
2181 int main(int argc, char **argv)
2182 {
2183         struct module *mod;
2184         char *missing_namespace_deps = NULL;
2185         char *unused_exports_white_list = NULL;
2186         char *dump_write = NULL, *files_source = NULL;
2187         int opt;
2188         LIST_HEAD(dump_lists);
2189         struct dump_list *dl, *dl2;
2190
2191         while ((opt = getopt(argc, argv, "ei:MmnT:to:au:WwENd:")) != -1) {
2192                 switch (opt) {
2193                 case 'e':
2194                         external_module = true;
2195                         break;
2196                 case 'i':
2197                         dl = NOFAIL(malloc(sizeof(*dl)));
2198                         dl->file = optarg;
2199                         list_add_tail(&dl->list, &dump_lists);
2200                         break;
2201                 case 'M':
2202                         module_enabled = true;
2203                         break;
2204                 case 'm':
2205                         modversions = true;
2206                         break;
2207                 case 'n':
2208                         ignore_missing_files = true;
2209                         break;
2210                 case 'o':
2211                         dump_write = optarg;
2212                         break;
2213                 case 'a':
2214                         all_versions = true;
2215                         break;
2216                 case 'T':
2217                         files_source = optarg;
2218                         break;
2219                 case 't':
2220                         trim_unused_exports = true;
2221                         break;
2222                 case 'u':
2223                         unused_exports_white_list = optarg;
2224                         break;
2225                 case 'W':
2226                         extra_warn = true;
2227                         break;
2228                 case 'w':
2229                         warn_unresolved = true;
2230                         break;
2231                 case 'E':
2232                         sec_mismatch_warn_only = false;
2233                         break;
2234                 case 'N':
2235                         allow_missing_ns_imports = true;
2236                         break;
2237                 case 'd':
2238                         missing_namespace_deps = optarg;
2239                         break;
2240                 default:
2241                         exit(1);
2242                 }
2243         }
2244
2245         list_for_each_entry_safe(dl, dl2, &dump_lists, list) {
2246                 read_dump(dl->file);
2247                 list_del(&dl->list);
2248                 free(dl);
2249         }
2250
2251         while (optind < argc)
2252                 read_symbols(argv[optind++]);
2253
2254         if (files_source)
2255                 read_symbols_from_files(files_source);
2256
2257         list_for_each_entry(mod, &modules, list) {
2258                 if (mod->from_dump || mod->is_vmlinux)
2259                         continue;
2260
2261                 check_modname_len(mod);
2262                 check_exports(mod);
2263         }
2264
2265         if (unused_exports_white_list)
2266                 handle_white_list_exports(unused_exports_white_list);
2267
2268         list_for_each_entry(mod, &modules, list) {
2269                 if (mod->from_dump)
2270                         continue;
2271
2272                 if (mod->is_vmlinux)
2273                         write_vmlinux_export_c_file(mod);
2274                 else
2275                         write_mod_c_file(mod);
2276         }
2277
2278         if (missing_namespace_deps)
2279                 write_namespace_deps_files(missing_namespace_deps);
2280
2281         if (dump_write)
2282                 write_dump(dump_write);
2283         if (sec_mismatch_count && !sec_mismatch_warn_only)
2284                 error("Section mismatches detected.\n"
2285                       "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");
2286
2287         if (nr_unresolved > MAX_UNRESOLVED_REPORTS)
2288                 warn("suppressed %u unresolved symbol warnings because there were too many)\n",
2289                      nr_unresolved - MAX_UNRESOLVED_REPORTS);
2290
2291         return error_occurred ? 1 : 0;
2292 }