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 #include "../../include/linux/module_symbol.h"
  26
  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 __attribute__((format(printf, 2, 3)))
  64 modpost_log(enum loglevel loglevel, const char *fmt, ...)
  65 {
  66         va_list arglist;
  67
  68         switch (loglevel) {
  69         case LOG_WARN:
  70                 fprintf(stderr, "WARNING: ");
  71                 break;
  72         case LOG_ERROR:
  73                 fprintf(stderr, "ERROR: ");
  74                 break;
  75         case LOG_FATAL:
  76                 fprintf(stderr, "FATAL: ");
  77                 break;
  78         default: /* invalid loglevel, ignore */
  79                 break;
  80         }
  81
  82         fprintf(stderr, "modpost: ");
  83
  84         va_start(arglist, fmt);
  85         vfprintf(stderr, fmt, arglist);
  86         va_end(arglist);
  87
  88         if (loglevel == LOG_FATAL)
  89                 exit(1);
  90         if (loglevel == LOG_ERROR)
  91                 error_occurred = true;
  92 }
  93
  94 static inline bool strends(const char *str, const char *postfix)
  95 {
  96         if (strlen(str) < strlen(postfix))
  97                 return false;
  98
  99         return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0;
 100 }
 101
 102 void *do_nofail(void *ptr, const char *expr)
 103 {
 104         if (!ptr)
 105                 fatal("Memory allocation failure: %s.\n", expr);
 106
 107         return ptr;
 108 }
 109
 110 char *read_text_file(const char *filename)
 111 {
 112         struct stat st;
 113         size_t nbytes;
 114         int fd;
 115         char *buf;
 116
 117         fd = open(filename, O_RDONLY);
 118         if (fd < 0) {
 119                 perror(filename);
 120                 exit(1);
 121         }
 122
 123         if (fstat(fd, &st) < 0) {
 124                 perror(filename);
 125                 exit(1);
 126         }
 127
 128         buf = NOFAIL(malloc(st.st_size + 1));
 129
 130         nbytes = st.st_size;
 131
 132         while (nbytes) {
 133                 ssize_t bytes_read;
 134
 135                 bytes_read = read(fd, buf, nbytes);
 136                 if (bytes_read < 0) {
 137                         perror(filename);
 138                         exit(1);
 139                 }
 140
 141                 nbytes -= bytes_read;
 142         }
 143         buf[st.st_size] = '\0';
 144
 145         close(fd);
 146
 147         return buf;
 148 }
 149
 150 char *get_line(char **stringp)
 151 {
 152         char *orig = *stringp, *next;
 153
 154         /* do not return the unwanted extra line at EOF */
 155         if (!orig || *orig == '\0')
 156                 return NULL;
 157
 158         /* don't use strsep here, it is not available everywhere */
 159         next = strchr(orig, '\n');
 160         if (next)
 161                 *next++ = '\0';
 162
 163         *stringp = next;
 164
 165         return orig;
 166 }
 167
 168 /* A list of all modules we processed */
 169 LIST_HEAD(modules);
 170
 171 static struct module *find_module(const char *modname)
 172 {
 173         struct module *mod;
 174
 175         list_for_each_entry(mod, &modules, list) {
 176                 if (strcmp(mod->name, modname) == 0)
 177                         return mod;
 178         }
 179         return NULL;
 180 }
 181
 182 static struct module *new_module(const char *name, size_t namelen)
 183 {
 184         struct module *mod;
 185
 186         mod = NOFAIL(malloc(sizeof(*mod) + namelen + 1));
 187         memset(mod, 0, sizeof(*mod));
 188
 189         INIT_LIST_HEAD(&mod->exported_symbols);
 190         INIT_LIST_HEAD(&mod->unresolved_symbols);
 191         INIT_LIST_HEAD(&mod->missing_namespaces);
 192         INIT_LIST_HEAD(&mod->imported_namespaces);
 193
 194         memcpy(mod->name, name, namelen);
 195         mod->name[namelen] = '\0';
 196         mod->is_vmlinux = (strcmp(mod->name, "vmlinux") == 0);
 197
 198         /*
 199          * Set mod->is_gpl_compatible to true by default. If MODULE_LICENSE()
 200          * is missing, do not check the use for EXPORT_SYMBOL_GPL() becasue
 201          * modpost will exit wiht error anyway.
 202          */
 203         mod->is_gpl_compatible = true;
 204
 205         list_add_tail(&mod->list, &modules);
 206
 207         return mod;
 208 }
 209
 210 /* A hash of all exported symbols,
 211  * struct symbol is also used for lists of unresolved symbols */
 212
 213 #define SYMBOL_HASH_SIZE 1024
 214
 215 struct symbol {
 216         struct symbol *next;
 217         struct list_head list;  /* link to module::exported_symbols or module::unresolved_symbols */
 218         struct module *module;
 219         char *namespace;
 220         unsigned int crc;
 221         bool crc_valid;
 222         bool weak;
 223         bool is_func;
 224         bool is_gpl_only;       /* exported by EXPORT_SYMBOL_GPL */
 225         bool used;              /* there exists a user of this symbol */
 226         char name[];
 227 };
 228
 229 static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
 230
 231 /* This is based on the hash algorithm from gdbm, via tdb */
 232 static inline unsigned int tdb_hash(const char *name)
 233 {
 234         unsigned value; /* Used to compute the hash value.  */
 235         unsigned   i;   /* Used to cycle through random values. */
 236
 237         /* Set the initial value from the key size. */
 238         for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
 239                 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
 240
 241         return (1103515243 * value + 12345);
 242 }
 243
 244 /**
 245  * Allocate a new symbols for use in the hash of exported symbols or
 246  * the list of unresolved symbols per module
 247  **/
 248 static struct symbol *alloc_symbol(const char *name)
 249 {
 250         struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
 251
 252         memset(s, 0, sizeof(*s));
 253         strcpy(s->name, name);
 254
 255         return s;
 256 }
 257
 258 /* For the hash of exported symbols */
 259 static void hash_add_symbol(struct symbol *sym)
 260 {
 261         unsigned int hash;
 262
 263         hash = tdb_hash(sym->name) % SYMBOL_HASH_SIZE;
 264         sym->next = symbolhash[hash];
 265         symbolhash[hash] = sym;
 266 }
 267
 268 static void sym_add_unresolved(const char *name, struct module *mod, bool weak)
 269 {
 270         struct symbol *sym;
 271
 272         sym = alloc_symbol(name);
 273         sym->weak = weak;
 274
 275         list_add_tail(&sym->list, &mod->unresolved_symbols);
 276 }
 277
 278 static struct symbol *sym_find_with_module(const char *name, struct module *mod)
 279 {
 280         struct symbol *s;
 281
 282         /* For our purposes, .foo matches foo.  PPC64 needs this. */
 283         if (name[0] == '.')
 284                 name++;
 285
 286         for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
 287                 if (strcmp(s->name, name) == 0 && (!mod || s->module == mod))
 288                         return s;
 289         }
 290         return NULL;
 291 }
 292
 293 static struct symbol *find_symbol(const char *name)
 294 {
 295         return sym_find_with_module(name, NULL);
 296 }
 297
 298 struct namespace_list {
 299         struct list_head list;
 300         char namespace[];
 301 };
 302
 303 static bool contains_namespace(struct list_head *head, const char *namespace)
 304 {
 305         struct namespace_list *list;
 306
 307         /*
 308          * The default namespace is null string "", which is always implicitly
 309          * contained.
 310          */
 311         if (!namespace[0])
 312                 return true;
 313
 314         list_for_each_entry(list, head, list) {
 315                 if (!strcmp(list->namespace, namespace))
 316                         return true;
 317         }
 318
 319         return false;
 320 }
 321
 322 static void add_namespace(struct list_head *head, const char *namespace)
 323 {
 324         struct namespace_list *ns_entry;
 325
 326         if (!contains_namespace(head, namespace)) {
 327                 ns_entry = NOFAIL(malloc(sizeof(*ns_entry) +
 328                                          strlen(namespace) + 1));
 329                 strcpy(ns_entry->namespace, namespace);
 330                 list_add_tail(&ns_entry->list, head);
 331         }
 332 }
 333
 334 static void *sym_get_data_by_offset(const struct elf_info *info,
 335                                     unsigned int secindex, unsigned long offset)
 336 {
 337         Elf_Shdr *sechdr = &info->sechdrs[secindex];
 338
 339         return (void *)info->hdr + sechdr->sh_offset + offset;
 340 }
 341
 342 void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym)
 343 {
 344         return sym_get_data_by_offset(info, get_secindex(info, sym),
 345                                       sym->st_value);
 346 }
 347
 348 static const char *sech_name(const struct elf_info *info, Elf_Shdr *sechdr)
 349 {
 350         return sym_get_data_by_offset(info, info->secindex_strings,
 351                                       sechdr->sh_name);
 352 }
 353
 354 static const char *sec_name(const struct elf_info *info, unsigned int secindex)
 355 {
 356         /*
 357          * If sym->st_shndx is a special section index, there is no
 358          * corresponding section header.
 359          * Return "" if the index is out of range of info->sechdrs[] array.
 360          */
 361         if (secindex >= info->num_sections)
 362                 return "";
 363
 364         return sech_name(info, &info->sechdrs[secindex]);
 365 }
 366
 367 #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)
 368
 369 static struct symbol *sym_add_exported(const char *name, struct module *mod,
 370                                        bool gpl_only, const char *namespace)
 371 {
 372         struct symbol *s = find_symbol(name);
 373
 374         if (s && (!external_module || s->module->is_vmlinux || s->module == mod)) {
 375                 error("%s: '%s' exported twice. Previous export was in %s%s\n",
 376                       mod->name, name, s->module->name,
 377                       s->module->is_vmlinux ? "" : ".ko");
 378         }
 379
 380         s = alloc_symbol(name);
 381         s->module = mod;
 382         s->is_gpl_only = gpl_only;
 383         s->namespace = NOFAIL(strdup(namespace));
 384         list_add_tail(&s->list, &mod->exported_symbols);
 385         hash_add_symbol(s);
 386
 387         return s;
 388 }
 389
 390 static void sym_set_crc(struct symbol *sym, unsigned int crc)
 391 {
 392         sym->crc = crc;
 393         sym->crc_valid = true;
 394 }
 395
 396 static void *grab_file(const char *filename, size_t *size)
 397 {
 398         struct stat st;
 399         void *map = MAP_FAILED;
 400         int fd;
 401
 402         fd = open(filename, O_RDONLY);
 403         if (fd < 0)
 404                 return NULL;
 405         if (fstat(fd, &st))
 406                 goto failed;
 407
 408         *size = st.st_size;
 409         map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
 410
 411 failed:
 412         close(fd);
 413         if (map == MAP_FAILED)
 414                 return NULL;
 415         return map;
 416 }
 417
 418 static void release_file(void *file, size_t size)
 419 {
 420         munmap(file, size);
 421 }
 422
 423 static int parse_elf(struct elf_info *info, const char *filename)
 424 {
 425         unsigned int i;
 426         Elf_Ehdr *hdr;
 427         Elf_Shdr *sechdrs;
 428         Elf_Sym  *sym;
 429         const char *secstrings;
 430         unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
 431
 432         hdr = grab_file(filename, &info->size);
 433         if (!hdr) {
 434                 if (ignore_missing_files) {
 435                         fprintf(stderr, "%s: %s (ignored)\n", filename,
 436                                 strerror(errno));
 437                         return 0;
 438                 }
 439                 perror(filename);
 440                 exit(1);
 441         }
 442         info->hdr = hdr;
 443         if (info->size < sizeof(*hdr)) {
 444                 /* file too small, assume this is an empty .o file */
 445                 return 0;
 446         }
 447         /* Is this a valid ELF file? */
 448         if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
 449             (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
 450             (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
 451             (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
 452                 /* Not an ELF file - silently ignore it */
 453                 return 0;
 454         }
 455         /* Fix endianness in ELF header */
 456         hdr->e_type      = TO_NATIVE(hdr->e_type);
 457         hdr->e_machine   = TO_NATIVE(hdr->e_machine);
 458         hdr->e_version   = TO_NATIVE(hdr->e_version);
 459         hdr->e_entry     = TO_NATIVE(hdr->e_entry);
 460         hdr->e_phoff     = TO_NATIVE(hdr->e_phoff);
 461         hdr->e_shoff     = TO_NATIVE(hdr->e_shoff);
 462         hdr->e_flags     = TO_NATIVE(hdr->e_flags);
 463         hdr->e_ehsize    = TO_NATIVE(hdr->e_ehsize);
 464         hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
 465         hdr->e_phnum     = TO_NATIVE(hdr->e_phnum);
 466         hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
 467         hdr->e_shnum     = TO_NATIVE(hdr->e_shnum);
 468         hdr->e_shstrndx  = TO_NATIVE(hdr->e_shstrndx);
 469         sechdrs = (void *)hdr + hdr->e_shoff;
 470         info->sechdrs = sechdrs;
 471
 472         /* modpost only works for relocatable objects */
 473         if (hdr->e_type != ET_REL)
 474                 fatal("%s: not relocatable object.", filename);
 475
 476         /* Check if file offset is correct */
 477         if (hdr->e_shoff > info->size) {
 478                 fatal("section header offset=%lu in file '%s' is bigger than filesize=%zu\n",
 479                       (unsigned long)hdr->e_shoff, filename, info->size);
 480                 return 0;
 481         }
 482
 483         if (hdr->e_shnum == SHN_UNDEF) {
 484                 /*
 485                  * There are more than 64k sections,
 486                  * read count from .sh_size.
 487                  */
 488                 info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
 489         }
 490         else {
 491                 info->num_sections = hdr->e_shnum;
 492         }
 493         if (hdr->e_shstrndx == SHN_XINDEX) {
 494                 info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
 495         }
 496         else {
 497                 info->secindex_strings = hdr->e_shstrndx;
 498         }
 499
 500         /* Fix endianness in section headers */
 501         for (i = 0; i < info->num_sections; i++) {
 502                 sechdrs[i].sh_name      = TO_NATIVE(sechdrs[i].sh_name);
 503                 sechdrs[i].sh_type      = TO_NATIVE(sechdrs[i].sh_type);
 504                 sechdrs[i].sh_flags     = TO_NATIVE(sechdrs[i].sh_flags);
 505                 sechdrs[i].sh_addr      = TO_NATIVE(sechdrs[i].sh_addr);
 506                 sechdrs[i].sh_offset    = TO_NATIVE(sechdrs[i].sh_offset);
 507                 sechdrs[i].sh_size      = TO_NATIVE(sechdrs[i].sh_size);
 508                 sechdrs[i].sh_link      = TO_NATIVE(sechdrs[i].sh_link);
 509                 sechdrs[i].sh_info      = TO_NATIVE(sechdrs[i].sh_info);
 510                 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
 511                 sechdrs[i].sh_entsize   = TO_NATIVE(sechdrs[i].sh_entsize);
 512         }
 513         /* Find symbol table. */
 514         secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
 515         for (i = 1; i < info->num_sections; i++) {
 516                 const char *secname;
 517                 int nobits = sechdrs[i].sh_type == SHT_NOBITS;
 518
 519                 if (!nobits && sechdrs[i].sh_offset > info->size) {
 520                         fatal("%s is truncated. sechdrs[i].sh_offset=%lu > sizeof(*hrd)=%zu\n",
 521                               filename, (unsigned long)sechdrs[i].sh_offset,
 522                               sizeof(*hdr));
 523                         return 0;
 524                 }
 525                 secname = secstrings + sechdrs[i].sh_name;
 526                 if (strcmp(secname, ".modinfo") == 0) {
 527                         if (nobits)
 528                                 fatal("%s has NOBITS .modinfo\n", filename);
 529                         info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
 530                         info->modinfo_len = sechdrs[i].sh_size;
 531                 } else if (!strcmp(secname, ".export_symbol")) {
 532                         info->export_symbol_secndx = i;
 533                 }
 534
 535                 if (sechdrs[i].sh_type == SHT_SYMTAB) {
 536                         unsigned int sh_link_idx;
 537                         symtab_idx = i;
 538                         info->symtab_start = (void *)hdr +
 539                             sechdrs[i].sh_offset;
 540                         info->symtab_stop  = (void *)hdr +
 541                             sechdrs[i].sh_offset + sechdrs[i].sh_size;
 542                         sh_link_idx = sechdrs[i].sh_link;
 543                         info->strtab       = (void *)hdr +
 544                             sechdrs[sh_link_idx].sh_offset;
 545                 }
 546
 547                 /* 32bit section no. table? ("more than 64k sections") */
 548                 if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
 549                         symtab_shndx_idx = i;
 550                         info->symtab_shndx_start = (void *)hdr +
 551                             sechdrs[i].sh_offset;
 552                         info->symtab_shndx_stop  = (void *)hdr +
 553                             sechdrs[i].sh_offset + sechdrs[i].sh_size;
 554                 }
 555         }
 556         if (!info->symtab_start)
 557                 fatal("%s has no symtab?\n", filename);
 558
 559         /* Fix endianness in symbols */
 560         for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
 561                 sym->st_shndx = TO_NATIVE(sym->st_shndx);
 562                 sym->st_name  = TO_NATIVE(sym->st_name);
 563                 sym->st_value = TO_NATIVE(sym->st_value);
 564                 sym->st_size  = TO_NATIVE(sym->st_size);
 565         }
 566
 567         if (symtab_shndx_idx != ~0U) {
 568                 Elf32_Word *p;
 569                 if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
 570                         fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
 571                               filename, sechdrs[symtab_shndx_idx].sh_link,
 572                               symtab_idx);
 573                 /* Fix endianness */
 574                 for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
 575                      p++)
 576                         *p = TO_NATIVE(*p);
 577         }
 578
 579         return 1;
 580 }
 581
 582 static void parse_elf_finish(struct elf_info *info)
 583 {
 584         release_file(info->hdr, info->size);
 585 }
 586
 587 static int ignore_undef_symbol(struct elf_info *info, const char *symname)
 588 {
 589         /* ignore __this_module, it will be resolved shortly */
 590         if (strcmp(symname, "__this_module") == 0)
 591                 return 1;
 592         /* ignore global offset table */
 593         if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
 594                 return 1;
 595         if (info->hdr->e_machine == EM_PPC)
 596                 /* Special register function linked on all modules during final link of .ko */
 597                 if (strstarts(symname, "_restgpr_") ||
 598                     strstarts(symname, "_savegpr_") ||
 599                     strstarts(symname, "_rest32gpr_") ||
 600                     strstarts(symname, "_save32gpr_") ||
 601                     strstarts(symname, "_restvr_") ||
 602                     strstarts(symname, "_savevr_"))
 603                         return 1;
 604         if (info->hdr->e_machine == EM_PPC64)
 605                 /* Special register function linked on all modules during final link of .ko */
 606                 if (strstarts(symname, "_restgpr0_") ||
 607                     strstarts(symname, "_savegpr0_") ||
 608                     strstarts(symname, "_restvr_") ||
 609                     strstarts(symname, "_savevr_") ||
 610                     strcmp(symname, ".TOC.") == 0)
 611                         return 1;
 612
 613         if (info->hdr->e_machine == EM_S390)
 614                 /* Expoline thunks are linked on all kernel modules during final link of .ko */
 615                 if (strstarts(symname, "__s390_indirect_jump_r"))
 616                         return 1;
 617         /* Do not ignore this symbol */
 618         return 0;
 619 }
 620
 621 static void handle_symbol(struct module *mod, struct elf_info *info,
 622                           const Elf_Sym *sym, const char *symname)
 623 {
 624         switch (sym->st_shndx) {
 625         case SHN_COMMON:
 626                 if (strstarts(symname, "__gnu_lto_")) {
 627                         /* Should warn here, but modpost runs before the linker */
 628                 } else
 629                         warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
 630                 break;
 631         case SHN_UNDEF:
 632                 /* undefined symbol */
 633                 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
 634                     ELF_ST_BIND(sym->st_info) != STB_WEAK)
 635                         break;
 636                 if (ignore_undef_symbol(info, symname))
 637                         break;
 638                 if (info->hdr->e_machine == EM_SPARC ||
 639                     info->hdr->e_machine == EM_SPARCV9) {
 640                         /* Ignore register directives. */
 641                         if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
 642                                 break;
 643                         if (symname[0] == '.') {
 644                                 char *munged = NOFAIL(strdup(symname));
 645                                 munged[0] = '_';
 646                                 munged[1] = toupper(munged[1]);
 647                                 symname = munged;
 648                         }
 649                 }
 650
 651                 sym_add_unresolved(symname, mod,
 652                                    ELF_ST_BIND(sym->st_info) == STB_WEAK);
 653                 break;
 654         default:
 655                 if (strcmp(symname, "init_module") == 0)
 656                         mod->has_init = true;
 657                 if (strcmp(symname, "cleanup_module") == 0)
 658                         mod->has_cleanup = true;
 659                 break;
 660         }
 661 }
 662
 663 /**
 664  * Parse tag=value strings from .modinfo section
 665  **/
 666 static char *next_string(char *string, unsigned long *secsize)
 667 {
 668         /* Skip non-zero chars */
 669         while (string[0]) {
 670                 string++;
 671                 if ((*secsize)-- <= 1)
 672                         return NULL;
 673         }
 674
 675         /* Skip any zero padding. */
 676         while (!string[0]) {
 677                 string++;
 678                 if ((*secsize)-- <= 1)
 679                         return NULL;
 680         }
 681         return string;
 682 }
 683
 684 static char *get_next_modinfo(struct elf_info *info, const char *tag,
 685                               char *prev)
 686 {
 687         char *p;
 688         unsigned int taglen = strlen(tag);
 689         char *modinfo = info->modinfo;
 690         unsigned long size = info->modinfo_len;
 691
 692         if (prev) {
 693                 size -= prev - modinfo;
 694                 modinfo = next_string(prev, &size);
 695         }
 696
 697         for (p = modinfo; p; p = next_string(p, &size)) {
 698                 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
 699                         return p + taglen + 1;
 700         }
 701         return NULL;
 702 }
 703
 704 static char *get_modinfo(struct elf_info *info, const char *tag)
 705
 706 {
 707         return get_next_modinfo(info, tag, NULL);
 708 }
 709
 710 static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
 711 {
 712         if (sym)
 713                 return elf->strtab + sym->st_name;
 714         else
 715                 return "(unknown)";
 716 }
 717
 718 /*
 719  * Check whether the 'string' argument matches one of the 'patterns',
 720  * an array of shell wildcard patterns (glob).
 721  *
 722  * Return true is there is a match.
 723  */
 724 static bool match(const char *string, const char *const patterns[])
 725 {
 726         const char *pattern;
 727
 728         while ((pattern = *patterns++)) {
 729                 if (!fnmatch(pattern, string, 0))
 730                         return true;
 731         }
 732
 733         return false;
 734 }
 735
 736 /* useful to pass patterns to match() directly */
 737 #define PATTERNS(...) \
 738         ({ \
 739                 static const char *const patterns[] = {__VA_ARGS__, NULL}; \
 740                 patterns; \
 741         })
 742
 743 /* sections that we do not want to do full section mismatch check on */
 744 static const char *const section_white_list[] =
 745 {
 746         ".comment*",
 747         ".debug*",
 748         ".zdebug*",             /* Compressed debug sections. */
 749         ".GCC.command.line",    /* record-gcc-switches */
 750         ".mdebug*",        /* alpha, score, mips etc. */
 751         ".pdr",            /* alpha, score, mips etc. */
 752         ".stab*",
 753         ".note*",
 754         ".got*",
 755         ".toc*",
 756         ".xt.prop",                              /* xtensa */
 757         ".xt.lit",         /* xtensa */
 758         ".arcextmap*",                  /* arc */
 759         ".gnu.linkonce.arcext*",        /* arc : modules */
 760         ".cmem*",                       /* EZchip */
 761         ".fmt_slot*",                   /* EZchip */
 762         ".gnu.lto*",
 763         ".discard.*",
 764         NULL
 765 };
 766
 767 /*
 768  * This is used to find sections missing the SHF_ALLOC flag.
 769  * The cause of this is often a section specified in assembler
 770  * without "ax" / "aw".
 771  */
 772 static void check_section(const char *modname, struct elf_info *elf,
 773                           Elf_Shdr *sechdr)
 774 {
 775         const char *sec = sech_name(elf, sechdr);
 776
 777         if (sechdr->sh_type == SHT_PROGBITS &&
 778             !(sechdr->sh_flags & SHF_ALLOC) &&
 779             !match(sec, section_white_list)) {
 780                 warn("%s (%s): unexpected non-allocatable section.\n"
 781                      "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
 782                      "Note that for example <linux/init.h> contains\n"
 783                      "section definitions for use in .S files.\n\n",
 784                      modname, sec);
 785         }
 786 }
 787
 788
 789
 790 #define ALL_INIT_DATA_SECTIONS \
 791         ".init.setup", ".init.rodata", ".meminit.rodata", \
 792         ".init.data", ".meminit.data"
 793 #define ALL_EXIT_DATA_SECTIONS \
 794         ".exit.data", ".memexit.data"
 795
 796 #define ALL_INIT_TEXT_SECTIONS \
 797         ".init.text", ".meminit.text"
 798 #define ALL_EXIT_TEXT_SECTIONS \
 799         ".exit.text", ".memexit.text"
 800
 801 #define ALL_PCI_INIT_SECTIONS   \
 802         ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
 803         ".pci_fixup_enable", ".pci_fixup_resume", \
 804         ".pci_fixup_resume_early", ".pci_fixup_suspend"
 805
 806 #define ALL_XXXINIT_SECTIONS MEM_INIT_SECTIONS
 807 #define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS
 808
 809 #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
 810 #define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
 811
 812 #define DATA_SECTIONS ".data", ".data.rel"
 813 #define TEXT_SECTIONS ".text", ".text.*", ".sched.text", \
 814                 ".kprobes.text", ".cpuidle.text", ".noinstr.text"
 815 #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
 816                 ".fixup", ".entry.text", ".exception.text", \
 817                 ".coldtext", ".softirqentry.text"
 818
 819 #define INIT_SECTIONS      ".init.*"
 820 #define MEM_INIT_SECTIONS  ".meminit.*"
 821
 822 #define EXIT_SECTIONS      ".exit.*"
 823 #define MEM_EXIT_SECTIONS  ".memexit.*"
 824
 825 #define ALL_TEXT_SECTIONS  ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \
 826                 TEXT_SECTIONS, OTHER_TEXT_SECTIONS
 827
 828 enum mismatch {
 829         TEXT_TO_ANY_INIT,
 830         DATA_TO_ANY_INIT,
 831         TEXTDATA_TO_ANY_EXIT,
 832         XXXINIT_TO_SOME_INIT,
 833         XXXEXIT_TO_SOME_EXIT,
 834         ANY_INIT_TO_ANY_EXIT,
 835         ANY_EXIT_TO_ANY_INIT,
 836         EXTABLE_TO_NON_TEXT,
 837 };
 838
 839 /**
 840  * Describe how to match sections on different criteria:
 841  *
 842  * @fromsec: Array of sections to be matched.
 843  *
 844  * @bad_tosec: Relocations applied to a section in @fromsec to a section in
 845  * this array is forbidden (black-list).  Can be empty.
 846  *
 847  * @good_tosec: Relocations applied to a section in @fromsec must be
 848  * targeting sections in this array (white-list).  Can be empty.
 849  *
 850  * @mismatch: Type of mismatch.
 851  */
 852 struct sectioncheck {
 853         const char *fromsec[20];
 854         const char *bad_tosec[20];
 855         const char *good_tosec[20];
 856         enum mismatch mismatch;
 857 };
 858
 859 static const struct sectioncheck sectioncheck[] = {
 860 /* Do not reference init/exit code/data from
 861  * normal code and data
 862  */
 863 {
 864         .fromsec = { TEXT_SECTIONS, NULL },
 865         .bad_tosec = { ALL_INIT_SECTIONS, NULL },
 866         .mismatch = TEXT_TO_ANY_INIT,
 867 },
 868 {
 869         .fromsec = { DATA_SECTIONS, NULL },
 870         .bad_tosec = { ALL_XXXINIT_SECTIONS, INIT_SECTIONS, NULL },
 871         .mismatch = DATA_TO_ANY_INIT,
 872 },
 873 {
 874         .fromsec = { TEXT_SECTIONS, DATA_SECTIONS, NULL },
 875         .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
 876         .mismatch = TEXTDATA_TO_ANY_EXIT,
 877 },
 878 /* Do not reference init code/data from meminit code/data */
 879 {
 880         .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
 881         .bad_tosec = { INIT_SECTIONS, NULL },
 882         .mismatch = XXXINIT_TO_SOME_INIT,
 883 },
 884 /* Do not reference exit code/data from memexit code/data */
 885 {
 886         .fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
 887         .bad_tosec = { EXIT_SECTIONS, NULL },
 888         .mismatch = XXXEXIT_TO_SOME_EXIT,
 889 },
 890 /* Do not use exit code/data from init code */
 891 {
 892         .fromsec = { ALL_INIT_SECTIONS, NULL },
 893         .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
 894         .mismatch = ANY_INIT_TO_ANY_EXIT,
 895 },
 896 /* Do not use init code/data from exit code */
 897 {
 898         .fromsec = { ALL_EXIT_SECTIONS, NULL },
 899         .bad_tosec = { ALL_INIT_SECTIONS, NULL },
 900         .mismatch = ANY_EXIT_TO_ANY_INIT,
 901 },
 902 {
 903         .fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
 904         .bad_tosec = { INIT_SECTIONS, NULL },
 905         .mismatch = ANY_INIT_TO_ANY_EXIT,
 906 },
 907 {
 908         .fromsec = { "__ex_table", NULL },
 909         /* If you're adding any new black-listed sections in here, consider
 910          * adding a special 'printer' for them in scripts/check_extable.
 911          */
 912         .bad_tosec = { ".altinstr_replacement", NULL },
 913         .good_tosec = {ALL_TEXT_SECTIONS , NULL},
 914         .mismatch = EXTABLE_TO_NON_TEXT,
 915 }
 916 };
 917
 918 static const struct sectioncheck *section_mismatch(
 919                 const char *fromsec, const char *tosec)
 920 {
 921         int i;
 922
 923         /*
 924          * The target section could be the SHT_NUL section when we're
 925          * handling relocations to un-resolved symbols, trying to match it
 926          * doesn't make much sense and causes build failures on parisc
 927          * architectures.
 928          */
 929         if (*tosec == '\0')
 930                 return NULL;
 931
 932         for (i = 0; i < ARRAY_SIZE(sectioncheck); i++) {
 933                 const struct sectioncheck *check = &sectioncheck[i];
 934
 935                 if (match(fromsec, check->fromsec)) {
 936                         if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
 937                                 return check;
 938                         if (check->good_tosec[0] && !match(tosec, check->good_tosec))
 939                                 return check;
 940                 }
 941         }
 942         return NULL;
 943 }
 944
 945 /**
 946  * Whitelist to allow certain references to pass with no warning.
 947  *
 948  * Pattern 1:
 949  *   If a module parameter is declared __initdata and permissions=0
 950  *   then this is legal despite the warning generated.
 951  *   We cannot see value of permissions here, so just ignore
 952  *   this pattern.
 953  *   The pattern is identified by:
 954  *   tosec   = .init.data
 955  *   fromsec = .data*
 956  *   atsym   =__param*
 957  *
 958  * Pattern 1a:
 959  *   module_param_call() ops can refer to __init set function if permissions=0
 960  *   The pattern is identified by:
 961  *   tosec   = .init.text
 962  *   fromsec = .data*
 963  *   atsym   = __param_ops_*
 964  *
 965  * Pattern 3:
 966  *   Whitelist all references from .head.text to any init section
 967  *
 968  * Pattern 4:
 969  *   Some symbols belong to init section but still it is ok to reference
 970  *   these from non-init sections as these symbols don't have any memory
 971  *   allocated for them and symbol address and value are same. So even
 972  *   if init section is freed, its ok to reference those symbols.
 973  *   For ex. symbols marking the init section boundaries.
 974  *   This pattern is identified by
 975  *   refsymname = __init_begin, _sinittext, _einittext
 976  *
 977  * Pattern 5:
 978  *   GCC may optimize static inlines when fed constant arg(s) resulting
 979  *   in functions like cpumask_empty() -- generating an associated symbol
 980  *   cpumask_empty.constprop.3 that appears in the audit.  If the const that
 981  *   is passed in comes from __init, like say nmi_ipi_mask, we get a
 982  *   meaningless section warning.  May need to add isra symbols too...
 983  *   This pattern is identified by
 984  *   tosec   = init section
 985  *   fromsec = text section
 986  *   refsymname = *.constprop.*
 987  *
 988  **/
 989 static int secref_whitelist(const char *fromsec, const char *fromsym,
 990                             const char *tosec, const char *tosym)
 991 {
 992         /* Check for pattern 1 */
 993         if (match(tosec, PATTERNS(ALL_INIT_DATA_SECTIONS)) &&
 994             match(fromsec, PATTERNS(DATA_SECTIONS)) &&
 995             strstarts(fromsym, "__param"))
 996                 return 0;
 997
 998         /* Check for pattern 1a */
 999         if (strcmp(tosec, ".init.text") == 0 &&
1000             match(fromsec, PATTERNS(DATA_SECTIONS)) &&
1001             strstarts(fromsym, "__param_ops_"))
1002                 return 0;
1003
1004         /* symbols in data sections that may refer to any init/exit sections */
1005         if (match(fromsec, PATTERNS(DATA_SECTIONS)) &&
1006             match(tosec, PATTERNS(ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS)) &&
1007             match(fromsym, PATTERNS("*_template", // scsi uses *_template a lot
1008                                     "*_timer", // arm uses ops structures named _timer a lot
1009                                     "*_sht", // scsi also used *_sht to some extent
1010                                     "*_ops",
1011                                     "*_probe",
1012                                     "*_probe_one",
1013                                     "*_console")))
1014                 return 0;
1015
1016         /* symbols in data sections that may refer to meminit/exit sections */
1017         if (match(fromsec, PATTERNS(DATA_SECTIONS)) &&
1018             match(tosec, PATTERNS(ALL_XXXINIT_SECTIONS, ALL_EXIT_SECTIONS)) &&
1019             match(fromsym, PATTERNS("*driver")))
1020                 return 0;
1021
1022         /* Check for pattern 3 */
1023         if (strstarts(fromsec, ".head.text") &&
1024             match(tosec, PATTERNS(ALL_INIT_SECTIONS)))
1025                 return 0;
1026
1027         /* Check for pattern 4 */
1028         if (match(tosym, PATTERNS("__init_begin", "_sinittext", "_einittext")))
1029                 return 0;
1030
1031         /* Check for pattern 5 */
1032         if (match(fromsec, PATTERNS(ALL_TEXT_SECTIONS)) &&
1033             match(tosec, PATTERNS(ALL_INIT_SECTIONS)) &&
1034             match(fromsym, PATTERNS("*.constprop.*")))
1035                 return 0;
1036
1037         return 1;
1038 }
1039
1040 /*
1041  * If there's no name there, ignore it; likewise, ignore it if it's
1042  * one of the magic symbols emitted used by current tools.
1043  *
1044  * Otherwise if find_symbols_between() returns those symbols, they'll
1045  * fail the whitelist tests and cause lots of false alarms ... fixable
1046  * only by merging __exit and __init sections into __text, bloating
1047  * the kernel (which is especially evil on embedded platforms).
1048  */
1049 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1050 {
1051         const char *name = elf->strtab + sym->st_name;
1052
1053         if (!name || !strlen(name))
1054                 return 0;
1055         return !is_mapping_symbol(name);
1056 }
1057
1058 /* Look up the nearest symbol based on the section and the address */
1059 static Elf_Sym *find_nearest_sym(struct elf_info *elf, Elf_Addr addr,
1060                                  unsigned int secndx, bool allow_negative,
1061                                  Elf_Addr min_distance)
1062 {
1063         Elf_Sym *sym;
1064         Elf_Sym *near = NULL;
1065         Elf_Addr sym_addr, distance;
1066         bool is_arm = (elf->hdr->e_machine == EM_ARM);
1067
1068         for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1069                 if (get_secindex(elf, sym) != secndx)
1070                         continue;
1071                 if (!is_valid_name(elf, sym))
1072                         continue;
1073
1074                 sym_addr = sym->st_value;
1075
1076                 /*
1077                  * For ARM Thumb instruction, the bit 0 of st_value is set
1078                  * if the symbol is STT_FUNC type. Mask it to get the address.
1079                  */
1080                 if (is_arm && ELF_ST_TYPE(sym->st_info) == STT_FUNC)
1081                          sym_addr &= ~1;
1082
1083                 if (addr >= sym_addr)
1084                         distance = addr - sym_addr;
1085                 else if (allow_negative)
1086                         distance = sym_addr - addr;
1087                 else
1088                         continue;
1089
1090                 if (distance <= min_distance) {
1091                         min_distance = distance;
1092                         near = sym;
1093                 }
1094
1095                 if (min_distance == 0)
1096                         break;
1097         }
1098         return near;
1099 }
1100
1101 static Elf_Sym *find_fromsym(struct elf_info *elf, Elf_Addr addr,
1102                              unsigned int secndx)
1103 {
1104         return find_nearest_sym(elf, addr, secndx, false, ~0);
1105 }
1106
1107 static Elf_Sym *find_tosym(struct elf_info *elf, Elf_Addr addr, Elf_Sym *sym)
1108 {
1109         /* If the supplied symbol has a valid name, return it */
1110         if (is_valid_name(elf, sym))
1111                 return sym;
1112
1113         /*
1114          * Strive to find a better symbol name, but the resulting name may not
1115          * match the symbol referenced in the original code.
1116          */
1117         return find_nearest_sym(elf, addr, get_secindex(elf, sym), true, 20);
1118 }
1119
1120 static bool is_executable_section(struct elf_info *elf, unsigned int secndx)
1121 {
1122         if (secndx >= elf->num_sections)
1123                 return false;
1124
1125         return (elf->sechdrs[secndx].sh_flags & SHF_EXECINSTR) != 0;
1126 }
1127
1128 static void default_mismatch_handler(const char *modname, struct elf_info *elf,
1129                                      const struct sectioncheck* const mismatch,
1130                                      Elf_Sym *tsym,
1131                                      unsigned int fsecndx, const char *fromsec, Elf_Addr faddr,
1132                                      const char *tosec, Elf_Addr taddr)
1133 {
1134         Elf_Sym *from;
1135         const char *tosym;
1136         const char *fromsym;
1137
1138         from = find_fromsym(elf, faddr, fsecndx);
1139         fromsym = sym_name(elf, from);
1140
1141         tsym = find_tosym(elf, taddr, tsym);
1142         tosym = sym_name(elf, tsym);
1143
1144         /* check whitelist - we may ignore it */
1145         if (!secref_whitelist(fromsec, fromsym, tosec, tosym))
1146                 return;
1147
1148         sec_mismatch_count++;
1149
1150         warn("%s: section mismatch in reference: %s+0x%x (section: %s) -> %s (section: %s)\n",
1151              modname, fromsym, (unsigned int)(faddr - from->st_value), fromsec, tosym, tosec);
1152
1153         if (mismatch->mismatch == EXTABLE_TO_NON_TEXT) {
1154                 if (match(tosec, mismatch->bad_tosec))
1155                         fatal("The relocation at %s+0x%lx references\n"
1156                               "section \"%s\" which is black-listed.\n"
1157                               "Something is seriously wrong and should be fixed.\n"
1158                               "You might get more information about where this is\n"
1159                               "coming from by using scripts/check_extable.sh %s\n",
1160                               fromsec, (long)faddr, tosec, modname);
1161                 else if (is_executable_section(elf, get_secindex(elf, tsym)))
1162                         warn("The relocation at %s+0x%lx references\n"
1163                              "section \"%s\" which is not in the list of\n"
1164                              "authorized sections.  If you're adding a new section\n"
1165                              "and/or if this reference is valid, add \"%s\" to the\n"
1166                              "list of authorized sections to jump to on fault.\n"
1167                              "This can be achieved by adding \"%s\" to\n"
1168                              "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
1169                              fromsec, (long)faddr, tosec, tosec, tosec);
1170                 else
1171                         error("%s+0x%lx references non-executable section '%s'\n",
1172                               fromsec, (long)faddr, tosec);
1173         }
1174 }
1175
1176 static void check_export_symbol(struct module *mod, struct elf_info *elf,
1177                                 Elf_Addr faddr, const char *secname,
1178                                 Elf_Sym *sym)
1179 {
1180         static const char *prefix = "__export_symbol_";
1181         const char *label_name, *name, *data;
1182         Elf_Sym *label;
1183         struct symbol *s;
1184         bool is_gpl;
1185
1186         label = find_fromsym(elf, faddr, elf->export_symbol_secndx);
1187         label_name = sym_name(elf, label);
1188
1189         if (!strstarts(label_name, prefix)) {
1190                 error("%s: .export_symbol section contains strange symbol '%s'\n",
1191                       mod->name, label_name);
1192                 return;
1193         }
1194
1195         if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
1196             ELF_ST_BIND(sym->st_info) != STB_WEAK) {
1197                 error("%s: local symbol '%s' was exported\n", mod->name,
1198                       label_name + strlen(prefix));
1199                 return;
1200         }
1201
1202         name = sym_name(elf, sym);
1203         if (strcmp(label_name + strlen(prefix), name)) {
1204                 error("%s: .export_symbol section references '%s', but it does not seem to be an export symbol\n",
1205                       mod->name, name);
1206                 return;
1207         }
1208
1209         data = sym_get_data(elf, label);        /* license */
1210         if (!strcmp(data, "GPL")) {
1211                 is_gpl = true;
1212         } else if (!strcmp(data, "")) {
1213                 is_gpl = false;
1214         } else {
1215                 error("%s: unknown license '%s' was specified for '%s'\n",
1216                       mod->name, data, name);
1217                 return;
1218         }
1219
1220         data += strlen(data) + 1;       /* namespace */
1221         s = sym_add_exported(name, mod, is_gpl, data);
1222
1223         /*
1224          * We need to be aware whether we are exporting a function or
1225          * a data on some architectures.
1226          */
1227         s->is_func = (ELF_ST_TYPE(sym->st_info) == STT_FUNC);
1228
1229         if (match(secname, PATTERNS(INIT_SECTIONS)))
1230                 warn("%s: %s: EXPORT_SYMBOL used for init symbol. Remove __init or EXPORT_SYMBOL.\n",
1231                      mod->name, name);
1232         else if (match(secname, PATTERNS(EXIT_SECTIONS)))
1233                 warn("%s: %s: EXPORT_SYMBOL used for exit symbol. Remove __exit or EXPORT_SYMBOL.\n",
1234                      mod->name, name);
1235 }
1236
1237 static void check_section_mismatch(struct module *mod, struct elf_info *elf,
1238                                    Elf_Sym *sym,
1239                                    unsigned int fsecndx, const char *fromsec,
1240                                    Elf_Addr faddr, Elf_Addr taddr)
1241 {
1242         const char *tosec = sec_name(elf, get_secindex(elf, sym));
1243         const struct sectioncheck *mismatch;
1244
1245         if (elf->export_symbol_secndx == fsecndx) {
1246                 check_export_symbol(mod, elf, faddr, tosec, sym);
1247                 return;
1248         }
1249
1250         mismatch = section_mismatch(fromsec, tosec);
1251         if (!mismatch)
1252                 return;
1253
1254         default_mismatch_handler(mod->name, elf, mismatch, sym,
1255                                  fsecndx, fromsec, faddr,
1256                                  tosec, taddr);
1257 }
1258
1259 static int addend_386_rel(uint32_t *location, Elf_Rela *r)
1260 {
1261         unsigned int r_typ = ELF_R_TYPE(r->r_info);
1262
1263         switch (r_typ) {
1264         case R_386_32:
1265                 r->r_addend = TO_NATIVE(*location);
1266                 break;
1267         case R_386_PC32:
1268                 r->r_addend = TO_NATIVE(*location) + 4;
1269                 break;
1270         default:
1271                 r->r_addend = (Elf_Addr)(-1);
1272         }
1273         return 0;
1274 }
1275
1276 #ifndef R_ARM_CALL
1277 #define R_ARM_CALL      28
1278 #endif
1279 #ifndef R_ARM_JUMP24
1280 #define R_ARM_JUMP24    29
1281 #endif
1282
1283 #ifndef R_ARM_THM_CALL
1284 #define R_ARM_THM_CALL          10
1285 #endif
1286 #ifndef R_ARM_THM_JUMP24
1287 #define R_ARM_THM_JUMP24        30
1288 #endif
1289
1290 #ifndef R_ARM_MOVW_ABS_NC
1291 #define R_ARM_MOVW_ABS_NC       43
1292 #endif
1293
1294 #ifndef R_ARM_MOVT_ABS
1295 #define R_ARM_MOVT_ABS          44
1296 #endif
1297
1298 #ifndef R_ARM_THM_MOVW_ABS_NC
1299 #define R_ARM_THM_MOVW_ABS_NC   47
1300 #endif
1301
1302 #ifndef R_ARM_THM_MOVT_ABS
1303 #define R_ARM_THM_MOVT_ABS      48
1304 #endif
1305
1306 #ifndef R_ARM_THM_JUMP19
1307 #define R_ARM_THM_JUMP19        51
1308 #endif
1309
1310 static int32_t sign_extend32(int32_t value, int index)
1311 {
1312         uint8_t shift = 31 - index;
1313
1314         return (int32_t)(value << shift) >> shift;
1315 }
1316
1317 static int addend_arm_rel(void *loc, Elf_Sym *sym, Elf_Rela *r)
1318 {
1319         unsigned int r_typ = ELF_R_TYPE(r->r_info);
1320         uint32_t inst, upper, lower, sign, j1, j2;
1321         int32_t offset;
1322
1323         switch (r_typ) {
1324         case R_ARM_ABS32:
1325         case R_ARM_REL32:
1326                 inst = TO_NATIVE(*(uint32_t *)loc);
1327                 r->r_addend = inst + sym->st_value;
1328                 break;
1329         case R_ARM_MOVW_ABS_NC:
1330         case R_ARM_MOVT_ABS:
1331                 inst = TO_NATIVE(*(uint32_t *)loc);
1332                 offset = sign_extend32(((inst & 0xf0000) >> 4) | (inst & 0xfff),
1333                                        15);
1334                 r->r_addend = offset + sym->st_value;
1335                 break;
1336         case R_ARM_PC24:
1337         case R_ARM_CALL:
1338         case R_ARM_JUMP24:
1339                 inst = TO_NATIVE(*(uint32_t *)loc);
1340                 offset = sign_extend32((inst & 0x00ffffff) << 2, 25);
1341                 r->r_addend = offset + sym->st_value + 8;
1342                 break;
1343         case R_ARM_THM_MOVW_ABS_NC:
1344         case R_ARM_THM_MOVT_ABS:
1345                 upper = TO_NATIVE(*(uint16_t *)loc);
1346                 lower = TO_NATIVE(*((uint16_t *)loc + 1));
1347                 offset = sign_extend32(((upper & 0x000f) << 12) |
1348                                        ((upper & 0x0400) << 1) |
1349                                        ((lower & 0x7000) >> 4) |
1350                                        (lower & 0x00ff),
1351                                        15);
1352                 r->r_addend = offset + sym->st_value;
1353                 break;
1354         case R_ARM_THM_JUMP19:
1355                 /*
1356                  * Encoding T3:
1357                  * S     = upper[10]
1358                  * imm6  = upper[5:0]
1359                  * J1    = lower[13]
1360                  * J2    = lower[11]
1361                  * imm11 = lower[10:0]
1362                  * imm32 = SignExtend(S:J2:J1:imm6:imm11:'0')
1363                  */
1364                 upper = TO_NATIVE(*(uint16_t *)loc);
1365                 lower = TO_NATIVE(*((uint16_t *)loc + 1));
1366
1367                 sign = (upper >> 10) & 1;
1368                 j1 = (lower >> 13) & 1;
1369                 j2 = (lower >> 11) & 1;
1370                 offset = sign_extend32((sign << 20) | (j2 << 19) | (j1 << 18) |
1371                                        ((upper & 0x03f) << 12) |
1372                                        ((lower & 0x07ff) << 1),
1373                                        20);
1374                 r->r_addend = offset + sym->st_value + 4;
1375                 break;
1376         case R_ARM_THM_CALL:
1377         case R_ARM_THM_JUMP24:
1378                 /*
1379                  * Encoding T4:
1380                  * S     = upper[10]
1381                  * imm10 = upper[9:0]
1382                  * J1    = lower[13]
1383                  * J2    = lower[11]
1384                  * imm11 = lower[10:0]
1385                  * I1    = NOT(J1 XOR S)
1386                  * I2    = NOT(J2 XOR S)
1387                  * imm32 = SignExtend(S:I1:I2:imm10:imm11:'0')
1388                  */
1389                 upper = TO_NATIVE(*(uint16_t *)loc);
1390                 lower = TO_NATIVE(*((uint16_t *)loc + 1));
1391
1392                 sign = (upper >> 10) & 1;
1393                 j1 = (lower >> 13) & 1;
1394                 j2 = (lower >> 11) & 1;
1395                 offset = sign_extend32((sign << 24) |
1396                                        ((~(j1 ^ sign) & 1) << 23) |
1397                                        ((~(j2 ^ sign) & 1) << 22) |
1398                                        ((upper & 0x03ff) << 12) |
1399                                        ((lower & 0x07ff) << 1),
1400                                        24);
1401                 r->r_addend = offset + sym->st_value + 4;
1402                 break;
1403         default:
1404                 r->r_addend = (Elf_Addr)(-1);
1405         }
1406         return 0;
1407 }
1408
1409 static int addend_mips_rel(uint32_t *location, Elf_Rela *r)
1410 {
1411         unsigned int r_typ = ELF_R_TYPE(r->r_info);
1412         uint32_t inst;
1413
1414         inst = TO_NATIVE(*location);
1415         switch (r_typ) {
1416         case R_MIPS_LO16:
1417                 r->r_addend = inst & 0xffff;
1418                 break;
1419         case R_MIPS_26:
1420                 r->r_addend = (inst & 0x03ffffff) << 2;
1421                 break;
1422         case R_MIPS_32:
1423                 r->r_addend = inst;
1424                 break;
1425         default:
1426                 r->r_addend = (Elf_Addr)(-1);
1427         }
1428         return 0;
1429 }
1430
1431 #ifndef EM_RISCV
1432 #define EM_RISCV                243
1433 #endif
1434
1435 #ifndef R_RISCV_SUB32
1436 #define R_RISCV_SUB32           39
1437 #endif
1438
1439 #ifndef EM_LOONGARCH
1440 #define EM_LOONGARCH            258
1441 #endif
1442
1443 #ifndef R_LARCH_SUB32
1444 #define R_LARCH_SUB32           55
1445 #endif
1446
1447 static void section_rela(struct module *mod, struct elf_info *elf,
1448                          Elf_Shdr *sechdr)
1449 {
1450         Elf_Rela *rela;
1451         Elf_Rela r;
1452         unsigned int r_sym;
1453         unsigned int fsecndx = sechdr->sh_info;
1454         const char *fromsec = sec_name(elf, fsecndx);
1455         Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1456         Elf_Rela *stop  = (void *)start + sechdr->sh_size;
1457
1458         /* if from section (name) is know good then skip it */
1459         if (match(fromsec, section_white_list))
1460                 return;
1461
1462         for (rela = start; rela < stop; rela++) {
1463                 r.r_offset = TO_NATIVE(rela->r_offset);
1464 #if KERNEL_ELFCLASS == ELFCLASS64
1465                 if (elf->hdr->e_machine == EM_MIPS) {
1466                         unsigned int r_typ;
1467                         r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1468                         r_sym = TO_NATIVE(r_sym);
1469                         r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1470                         r.r_info = ELF64_R_INFO(r_sym, r_typ);
1471                 } else {
1472                         r.r_info = TO_NATIVE(rela->r_info);
1473                         r_sym = ELF_R_SYM(r.r_info);
1474                 }
1475 #else
1476                 r.r_info = TO_NATIVE(rela->r_info);
1477                 r_sym = ELF_R_SYM(r.r_info);
1478 #endif
1479                 r.r_addend = TO_NATIVE(rela->r_addend);
1480                 switch (elf->hdr->e_machine) {
1481                 case EM_RISCV:
1482                         if (!strcmp("__ex_table", fromsec) &&
1483                             ELF_R_TYPE(r.r_info) == R_RISCV_SUB32)
1484                                 continue;
1485                         break;
1486                 case EM_LOONGARCH:
1487                         if (!strcmp("__ex_table", fromsec) &&
1488                             ELF_R_TYPE(r.r_info) == R_LARCH_SUB32)
1489                                 continue;
1490                         break;
1491                 }
1492
1493                 check_section_mismatch(mod, elf, elf->symtab_start + r_sym,
1494                                        fsecndx, fromsec, r.r_offset, r.r_addend);
1495         }
1496 }
1497
1498 static void section_rel(struct module *mod, struct elf_info *elf,
1499                         Elf_Shdr *sechdr)
1500 {
1501         Elf_Rel *rel;
1502         Elf_Rela r;
1503         unsigned int r_sym;
1504         unsigned int fsecndx = sechdr->sh_info;
1505         const char *fromsec = sec_name(elf, fsecndx);
1506         Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1507         Elf_Rel *stop  = (void *)start + sechdr->sh_size;
1508
1509         /* if from section (name) is know good then skip it */
1510         if (match(fromsec, section_white_list))
1511                 return;
1512
1513         for (rel = start; rel < stop; rel++) {
1514                 Elf_Sym *tsym;
1515                 void *loc;
1516
1517                 r.r_offset = TO_NATIVE(rel->r_offset);
1518 #if KERNEL_ELFCLASS == ELFCLASS64
1519                 if (elf->hdr->e_machine == EM_MIPS) {
1520                         unsigned int r_typ;
1521                         r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1522                         r_sym = TO_NATIVE(r_sym);
1523                         r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1524                         r.r_info = ELF64_R_INFO(r_sym, r_typ);
1525                 } else {
1526                         r.r_info = TO_NATIVE(rel->r_info);
1527                         r_sym = ELF_R_SYM(r.r_info);
1528                 }
1529 #else
1530                 r.r_info = TO_NATIVE(rel->r_info);
1531                 r_sym = ELF_R_SYM(r.r_info);
1532 #endif
1533                 r.r_addend = 0;
1534
1535                 loc = sym_get_data_by_offset(elf, fsecndx, r.r_offset);
1536                 tsym = elf->symtab_start + r_sym;
1537
1538                 switch (elf->hdr->e_machine) {
1539                 case EM_386:
1540                         addend_386_rel(loc, &r);
1541                         break;
1542                 case EM_ARM:
1543                         addend_arm_rel(loc, tsym, &r);
1544                         break;
1545                 case EM_MIPS:
1546                         addend_mips_rel(loc, &r);
1547                         break;
1548                 default:
1549                         fatal("Please add code to calculate addend for this architecture\n");
1550                 }
1551
1552                 check_section_mismatch(mod, elf, tsym,
1553                                        fsecndx, fromsec, r.r_offset, r.r_addend);
1554         }
1555 }
1556
1557 /**
1558  * A module includes a number of sections that are discarded
1559  * either when loaded or when used as built-in.
1560  * For loaded modules all functions marked __init and all data
1561  * marked __initdata will be discarded when the module has been initialized.
1562  * Likewise for modules used built-in the sections marked __exit
1563  * are discarded because __exit marked function are supposed to be called
1564  * only when a module is unloaded which never happens for built-in modules.
1565  * The check_sec_ref() function traverses all relocation records
1566  * to find all references to a section that reference a section that will
1567  * be discarded and warns about it.
1568  **/
1569 static void check_sec_ref(struct module *mod, struct elf_info *elf)
1570 {
1571         int i;
1572         Elf_Shdr *sechdrs = elf->sechdrs;
1573
1574         /* Walk through all sections */
1575         for (i = 0; i < elf->num_sections; i++) {
1576                 check_section(mod->name, elf, &elf->sechdrs[i]);
1577                 /* We want to process only relocation sections and not .init */
1578                 if (sechdrs[i].sh_type == SHT_RELA)
1579                         section_rela(mod, elf, &elf->sechdrs[i]);
1580                 else if (sechdrs[i].sh_type == SHT_REL)
1581                         section_rel(mod, elf, &elf->sechdrs[i]);
1582         }
1583 }
1584
1585 static char *remove_dot(char *s)
1586 {
1587         size_t n = strcspn(s, ".");
1588
1589         if (n && s[n]) {
1590                 size_t m = strspn(s + n + 1, "0123456789");
1591                 if (m && (s[n + m + 1] == '.' || s[n + m + 1] == 0))
1592                         s[n] = 0;
1593         }
1594         return s;
1595 }
1596
1597 /*
1598  * The CRCs are recorded in .*.cmd files in the form of:
1599  * #SYMVER <name> <crc>
1600  */
1601 static void extract_crcs_for_object(const char *object, struct module *mod)
1602 {
1603         char cmd_file[PATH_MAX];
1604         char *buf, *p;
1605         const char *base;
1606         int dirlen, ret;
1607
1608         base = strrchr(object, '/');
1609         if (base) {
1610                 base++;
1611                 dirlen = base - object;
1612         } else {
1613                 dirlen = 0;
1614                 base = object;
1615         }
1616
1617         ret = snprintf(cmd_file, sizeof(cmd_file), "%.*s.%s.cmd",
1618                        dirlen, object, base);
1619         if (ret >= sizeof(cmd_file)) {
1620                 error("%s: too long path was truncated\n", cmd_file);
1621                 return;
1622         }
1623
1624         buf = read_text_file(cmd_file);
1625         p = buf;
1626
1627         while ((p = strstr(p, "\n#SYMVER "))) {
1628                 char *name;
1629                 size_t namelen;
1630                 unsigned int crc;
1631                 struct symbol *sym;
1632
1633                 name = p + strlen("\n#SYMVER ");
1634
1635                 p = strchr(name, ' ');
1636                 if (!p)
1637                         break;
1638
1639                 namelen = p - name;
1640                 p++;
1641
1642                 if (!isdigit(*p))
1643                         continue;       /* skip this line */
1644
1645                 crc = strtoul(p, &p, 0);
1646                 if (*p != '\n')
1647                         continue;       /* skip this line */
1648
1649                 name[namelen] = '\0';
1650
1651                 /*
1652                  * sym_find_with_module() may return NULL here.
1653                  * It typically occurs when CONFIG_TRIM_UNUSED_KSYMS=y.
1654                  * Since commit e1327a127703, genksyms calculates CRCs of all
1655                  * symbols, including trimmed ones. Ignore orphan CRCs.
1656                  */
1657                 sym = sym_find_with_module(name, mod);
1658                 if (sym)
1659                         sym_set_crc(sym, crc);
1660         }
1661
1662         free(buf);
1663 }
1664
1665 /*
1666  * The symbol versions (CRC) are recorded in the .*.cmd files.
1667  * Parse them to retrieve CRCs for the current module.
1668  */
1669 static void mod_set_crcs(struct module *mod)
1670 {
1671         char objlist[PATH_MAX];
1672         char *buf, *p, *obj;
1673         int ret;
1674
1675         if (mod->is_vmlinux) {
1676                 strcpy(objlist, ".vmlinux.objs");
1677         } else {
1678                 /* objects for a module are listed in the *.mod file. */
1679                 ret = snprintf(objlist, sizeof(objlist), "%s.mod", mod->name);
1680                 if (ret >= sizeof(objlist)) {
1681                         error("%s: too long path was truncated\n", objlist);
1682                         return;
1683                 }
1684         }
1685
1686         buf = read_text_file(objlist);
1687         p = buf;
1688
1689         while ((obj = strsep(&p, "\n")) && obj[0])
1690                 extract_crcs_for_object(obj, mod);
1691
1692         free(buf);
1693 }
1694
1695 static void read_symbols(const char *modname)
1696 {
1697         const char *symname;
1698         char *version;
1699         char *license;
1700         char *namespace;
1701         struct module *mod;
1702         struct elf_info info = { };
1703         Elf_Sym *sym;
1704
1705         if (!parse_elf(&info, modname))
1706                 return;
1707
1708         if (!strends(modname, ".o")) {
1709                 error("%s: filename must be suffixed with .o\n", modname);
1710                 return;
1711         }
1712
1713         /* strip trailing .o */
1714         mod = new_module(modname, strlen(modname) - strlen(".o"));
1715
1716         if (!mod->is_vmlinux) {
1717                 license = get_modinfo(&info, "license");
1718                 if (!license)
1719                         error("missing MODULE_LICENSE() in %s\n", modname);
1720                 while (license) {
1721                         if (!license_is_gpl_compatible(license)) {
1722                                 mod->is_gpl_compatible = false;
1723                                 break;
1724                         }
1725                         license = get_next_modinfo(&info, "license", license);
1726                 }
1727
1728                 namespace = get_modinfo(&info, "import_ns");
1729                 while (namespace) {
1730                         add_namespace(&mod->imported_namespaces, namespace);
1731                         namespace = get_next_modinfo(&info, "import_ns",
1732                                                      namespace);
1733                 }
1734         }
1735
1736         if (extra_warn && !get_modinfo(&info, "description"))
1737                 warn("missing MODULE_DESCRIPTION() in %s\n", modname);
1738         for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1739                 symname = remove_dot(info.strtab + sym->st_name);
1740
1741                 handle_symbol(mod, &info, sym, symname);
1742                 handle_moddevtable(mod, &info, sym, symname);
1743         }
1744
1745         check_sec_ref(mod, &info);
1746
1747         if (!mod->is_vmlinux) {
1748                 version = get_modinfo(&info, "version");
1749                 if (version || all_versions)
1750                         get_src_version(mod->name, mod->srcversion,
1751                                         sizeof(mod->srcversion) - 1);
1752         }
1753
1754         parse_elf_finish(&info);
1755
1756         if (modversions) {
1757                 /*
1758                  * Our trick to get versioning for module struct etc. - it's
1759                  * never passed as an argument to an exported function, so
1760                  * the automatic versioning doesn't pick it up, but it's really
1761                  * important anyhow.
1762                  */
1763                 sym_add_unresolved("module_layout", mod, false);
1764
1765                 mod_set_crcs(mod);
1766         }
1767 }
1768
1769 static void read_symbols_from_files(const char *filename)
1770 {
1771         FILE *in = stdin;
1772         char fname[PATH_MAX];
1773
1774         in = fopen(filename, "r");
1775         if (!in)
1776                 fatal("Can't open filenames file %s: %m", filename);
1777
1778         while (fgets(fname, PATH_MAX, in) != NULL) {
1779                 if (strends(fname, "\n"))
1780                         fname[strlen(fname)-1] = '\0';
1781                 read_symbols(fname);
1782         }
1783
1784         fclose(in);
1785 }
1786
1787 #define SZ 500
1788
1789 /* We first write the generated file into memory using the
1790  * following helper, then compare to the file on disk and
1791  * only update the later if anything changed */
1792
1793 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
1794                                                       const char *fmt, ...)
1795 {
1796         char tmp[SZ];
1797         int len;
1798         va_list ap;
1799
1800         va_start(ap, fmt);
1801         len = vsnprintf(tmp, SZ, fmt, ap);
1802         buf_write(buf, tmp, len);
1803         va_end(ap);
1804 }
1805
1806 void buf_write(struct buffer *buf, const char *s, int len)
1807 {
1808         if (buf->size - buf->pos < len) {
1809                 buf->size += len + SZ;
1810                 buf->p = NOFAIL(realloc(buf->p, buf->size));
1811         }
1812         strncpy(buf->p + buf->pos, s, len);
1813         buf->pos += len;
1814 }
1815
1816 static void check_exports(struct module *mod)
1817 {
1818         struct symbol *s, *exp;
1819
1820         list_for_each_entry(s, &mod->unresolved_symbols, list) {
1821                 const char *basename;
1822                 exp = find_symbol(s->name);
1823                 if (!exp) {
1824                         if (!s->weak && nr_unresolved++ < MAX_UNRESOLVED_REPORTS)
1825                                 modpost_log(warn_unresolved ? LOG_WARN : LOG_ERROR,
1826                                             "\"%s\" [%s.ko] undefined!\n",
1827                                             s->name, mod->name);
1828                         continue;
1829                 }
1830                 if (exp->module == mod) {
1831                         error("\"%s\" [%s.ko] was exported without definition\n",
1832                               s->name, mod->name);
1833                         continue;
1834                 }
1835
1836                 exp->used = true;
1837                 s->module = exp->module;
1838                 s->crc_valid = exp->crc_valid;
1839                 s->crc = exp->crc;
1840
1841                 basename = strrchr(mod->name, '/');
1842                 if (basename)
1843                         basename++;
1844                 else
1845                         basename = mod->name;
1846
1847                 if (!contains_namespace(&mod->imported_namespaces, exp->namespace)) {
1848                         modpost_log(allow_missing_ns_imports ? LOG_WARN : LOG_ERROR,
1849                                     "module %s uses symbol %s from namespace %s, but does not import it.\n",
1850                                     basename, exp->name, exp->namespace);
1851                         add_namespace(&mod->missing_namespaces, exp->namespace);
1852                 }
1853
1854                 if (!mod->is_gpl_compatible && exp->is_gpl_only)
1855                         error("GPL-incompatible module %s.ko uses GPL-only symbol '%s'\n",
1856                               basename, exp->name);
1857         }
1858 }
1859
1860 static void handle_white_list_exports(const char *white_list)
1861 {
1862         char *buf, *p, *name;
1863
1864         buf = read_text_file(white_list);
1865         p = buf;
1866
1867         while ((name = strsep(&p, "\n"))) {
1868                 struct symbol *sym = find_symbol(name);
1869
1870                 if (sym)
1871                         sym->used = true;
1872         }
1873
1874         free(buf);
1875 }
1876
1877 static void check_modname_len(struct module *mod)
1878 {
1879         const char *mod_name;
1880
1881         mod_name = strrchr(mod->name, '/');
1882         if (mod_name == NULL)
1883                 mod_name = mod->name;
1884         else
1885                 mod_name++;
1886         if (strlen(mod_name) >= MODULE_NAME_LEN)
1887                 error("module name is too long [%s.ko]\n", mod->name);
1888 }
1889
1890 /**
1891  * Header for the generated file
1892  **/
1893 static void add_header(struct buffer *b, struct module *mod)
1894 {
1895         buf_printf(b, "#include <linux/module.h>\n");
1896         /*
1897          * Include build-salt.h after module.h in order to
1898          * inherit the definitions.
1899          */
1900         buf_printf(b, "#define INCLUDE_VERMAGIC\n");
1901         buf_printf(b, "#include <linux/build-salt.h>\n");
1902         buf_printf(b, "#include <linux/elfnote-lto.h>\n");
1903         buf_printf(b, "#include <linux/export-internal.h>\n");
1904         buf_printf(b, "#include <linux/vermagic.h>\n");
1905         buf_printf(b, "#include <linux/compiler.h>\n");
1906         buf_printf(b, "\n");
1907         buf_printf(b, "#ifdef CONFIG_UNWINDER_ORC\n");
1908         buf_printf(b, "#include <asm/orc_header.h>\n");
1909         buf_printf(b, "ORC_HEADER;\n");
1910         buf_printf(b, "#endif\n");
1911         buf_printf(b, "\n");
1912         buf_printf(b, "BUILD_SALT;\n");
1913         buf_printf(b, "BUILD_LTO_INFO;\n");
1914         buf_printf(b, "\n");
1915         buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
1916         buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n");
1917         buf_printf(b, "\n");
1918         buf_printf(b, "__visible struct module __this_module\n");
1919         buf_printf(b, "__section(\".gnu.linkonce.this_module\") = {\n");
1920         buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
1921         if (mod->has_init)
1922                 buf_printf(b, "\t.init = init_module,\n");
1923         if (mod->has_cleanup)
1924                 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
1925                               "\t.exit = cleanup_module,\n"
1926                               "#endif\n");
1927         buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
1928         buf_printf(b, "};\n");
1929
1930         if (!external_module)
1931                 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
1932
1933         buf_printf(b,
1934                    "\n"
1935                    "#ifdef CONFIG_RETPOLINE\n"
1936                    "MODULE_INFO(retpoline, \"Y\");\n"
1937                    "#endif\n");
1938
1939         if (strstarts(mod->name, "drivers/staging"))
1940                 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
1941
1942         if (strstarts(mod->name, "tools/testing"))
1943                 buf_printf(b, "\nMODULE_INFO(test, \"Y\");\n");
1944 }
1945
1946 static void add_exported_symbols(struct buffer *buf, struct module *mod)
1947 {
1948         struct symbol *sym;
1949
1950         /* generate struct for exported symbols */
1951         buf_printf(buf, "\n");
1952         list_for_each_entry(sym, &mod->exported_symbols, list) {
1953                 if (trim_unused_exports && !sym->used)
1954                         continue;
1955
1956                 buf_printf(buf, "KSYMTAB_%s(%s, \"%s\", \"%s\");\n",
1957                            sym->is_func ? "FUNC" : "DATA", sym->name,
1958                            sym->is_gpl_only ? "_gpl" : "", sym->namespace);
1959         }
1960
1961         if (!modversions)
1962                 return;
1963
1964         /* record CRCs for exported symbols */
1965         buf_printf(buf, "\n");
1966         list_for_each_entry(sym, &mod->exported_symbols, list) {
1967                 if (trim_unused_exports && !sym->used)
1968                         continue;
1969
1970                 if (!sym->crc_valid)
1971                         warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n"
1972                              "Is \"%s\" prototyped in <asm/asm-prototypes.h>?\n",
1973                              sym->name, mod->name, mod->is_vmlinux ? "" : ".ko",
1974                              sym->name);
1975
1976                 buf_printf(buf, "SYMBOL_CRC(%s, 0x%08x, \"%s\");\n",
1977                            sym->name, sym->crc, sym->is_gpl_only ? "_gpl" : "");
1978         }
1979 }
1980
1981 /**
1982  * Record CRCs for unresolved symbols
1983  **/
1984 static void add_versions(struct buffer *b, struct module *mod)
1985 {
1986         struct symbol *s;
1987
1988         if (!modversions)
1989                 return;
1990
1991         buf_printf(b, "\n");
1992         buf_printf(b, "static const struct modversion_info ____versions[]\n");
1993         buf_printf(b, "__used __section(\"__versions\") = {\n");
1994
1995         list_for_each_entry(s, &mod->unresolved_symbols, list) {
1996                 if (!s->module)
1997                         continue;
1998                 if (!s->crc_valid) {
1999                         warn("\"%s\" [%s.ko] has no CRC!\n",
2000                                 s->name, mod->name);
2001                         continue;
2002                 }
2003                 if (strlen(s->name) >= MODULE_NAME_LEN) {
2004                         error("too long symbol \"%s\" [%s.ko]\n",
2005                               s->name, mod->name);
2006                         break;
2007                 }
2008                 buf_printf(b, "\t{ %#8x, \"%s\" },\n",
2009                            s->crc, s->name);
2010         }
2011
2012         buf_printf(b, "};\n");
2013 }
2014
2015 static void add_depends(struct buffer *b, struct module *mod)
2016 {
2017         struct symbol *s;
2018         int first = 1;
2019
2020         /* Clear ->seen flag of modules that own symbols needed by this. */
2021         list_for_each_entry(s, &mod->unresolved_symbols, list) {
2022                 if (s->module)
2023                         s->module->seen = s->module->is_vmlinux;
2024         }
2025
2026         buf_printf(b, "\n");
2027         buf_printf(b, "MODULE_INFO(depends, \"");
2028         list_for_each_entry(s, &mod->unresolved_symbols, list) {
2029                 const char *p;
2030                 if (!s->module)
2031                         continue;
2032
2033                 if (s->module->seen)
2034                         continue;
2035
2036                 s->module->seen = true;
2037                 p = strrchr(s->module->name, '/');
2038                 if (p)
2039                         p++;
2040                 else
2041                         p = s->module->name;
2042                 buf_printf(b, "%s%s", first ? "" : ",", p);
2043                 first = 0;
2044         }
2045         buf_printf(b, "\");\n");
2046 }
2047
2048 static void add_srcversion(struct buffer *b, struct module *mod)
2049 {
2050         if (mod->srcversion[0]) {
2051                 buf_printf(b, "\n");
2052                 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
2053                            mod->srcversion);
2054         }
2055 }
2056
2057 static void write_buf(struct buffer *b, const char *fname)
2058 {
2059         FILE *file;
2060
2061         if (error_occurred)
2062                 return;
2063
2064         file = fopen(fname, "w");
2065         if (!file) {
2066                 perror(fname);
2067                 exit(1);
2068         }
2069         if (fwrite(b->p, 1, b->pos, file) != b->pos) {
2070                 perror(fname);
2071                 exit(1);
2072         }
2073         if (fclose(file) != 0) {
2074                 perror(fname);
2075                 exit(1);
2076         }
2077 }
2078
2079 static void write_if_changed(struct buffer *b, const char *fname)
2080 {
2081         char *tmp;
2082         FILE *file;
2083         struct stat st;
2084
2085         file = fopen(fname, "r");
2086         if (!file)
2087                 goto write;
2088
2089         if (fstat(fileno(file), &st) < 0)
2090                 goto close_write;
2091
2092         if (st.st_size != b->pos)
2093                 goto close_write;
2094
2095         tmp = NOFAIL(malloc(b->pos));
2096         if (fread(tmp, 1, b->pos, file) != b->pos)
2097                 goto free_write;
2098
2099         if (memcmp(tmp, b->p, b->pos) != 0)
2100                 goto free_write;
2101
2102         free(tmp);
2103         fclose(file);
2104         return;
2105
2106  free_write:
2107         free(tmp);
2108  close_write:
2109         fclose(file);
2110  write:
2111         write_buf(b, fname);
2112 }
2113
2114 static void write_vmlinux_export_c_file(struct module *mod)
2115 {
2116         struct buffer buf = { };
2117
2118         buf_printf(&buf,
2119                    "#include <linux/export-internal.h>\n");
2120
2121         add_exported_symbols(&buf, mod);
2122         write_if_changed(&buf, ".vmlinux.export.c");
2123         free(buf.p);
2124 }
2125
2126 /* do sanity checks, and generate *.mod.c file */
2127 static void write_mod_c_file(struct module *mod)
2128 {
2129         struct buffer buf = { };
2130         char fname[PATH_MAX];
2131         int ret;
2132
2133         add_header(&buf, mod);
2134         add_exported_symbols(&buf, mod);
2135         add_versions(&buf, mod);
2136         add_depends(&buf, mod);
2137         add_moddevtable(&buf, mod);
2138         add_srcversion(&buf, mod);
2139
2140         ret = snprintf(fname, sizeof(fname), "%s.mod.c", mod->name);
2141         if (ret >= sizeof(fname)) {
2142                 error("%s: too long path was truncated\n", fname);
2143                 goto free;
2144         }
2145
2146         write_if_changed(&buf, fname);
2147
2148 free:
2149         free(buf.p);
2150 }
2151
2152 /* parse Module.symvers file. line format:
2153  * 0x12345678<tab>symbol<tab>module<tab>export<tab>namespace
2154  **/
2155 static void read_dump(const char *fname)
2156 {
2157         char *buf, *pos, *line;
2158
2159         buf = read_text_file(fname);
2160         if (!buf)
2161                 /* No symbol versions, silently ignore */
2162                 return;
2163
2164         pos = buf;
2165
2166         while ((line = get_line(&pos))) {
2167                 char *symname, *namespace, *modname, *d, *export;
2168                 unsigned int crc;
2169                 struct module *mod;
2170                 struct symbol *s;
2171                 bool gpl_only;
2172
2173                 if (!(symname = strchr(line, '\t')))
2174                         goto fail;
2175                 *symname++ = '\0';
2176                 if (!(modname = strchr(symname, '\t')))
2177                         goto fail;
2178                 *modname++ = '\0';
2179                 if (!(export = strchr(modname, '\t')))
2180                         goto fail;
2181                 *export++ = '\0';
2182                 if (!(namespace = strchr(export, '\t')))
2183                         goto fail;
2184                 *namespace++ = '\0';
2185
2186                 crc = strtoul(line, &d, 16);
2187                 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2188                         goto fail;
2189
2190                 if (!strcmp(export, "EXPORT_SYMBOL_GPL")) {
2191                         gpl_only = true;
2192                 } else if (!strcmp(export, "EXPORT_SYMBOL")) {
2193                         gpl_only = false;
2194                 } else {
2195                         error("%s: unknown license %s. skip", symname, export);
2196                         continue;
2197                 }
2198
2199                 mod = find_module(modname);
2200                 if (!mod) {
2201                         mod = new_module(modname, strlen(modname));
2202                         mod->from_dump = true;
2203                 }
2204                 s = sym_add_exported(symname, mod, gpl_only, namespace);
2205                 sym_set_crc(s, crc);
2206         }
2207         free(buf);
2208         return;
2209 fail:
2210         free(buf);
2211         fatal("parse error in symbol dump file\n");
2212 }
2213
2214 static void write_dump(const char *fname)
2215 {
2216         struct buffer buf = { };
2217         struct module *mod;
2218         struct symbol *sym;
2219
2220         list_for_each_entry(mod, &modules, list) {
2221                 if (mod->from_dump)
2222                         continue;
2223                 list_for_each_entry(sym, &mod->exported_symbols, list) {
2224                         if (trim_unused_exports && !sym->used)
2225                                 continue;
2226
2227                         buf_printf(&buf, "0x%08x\t%s\t%s\tEXPORT_SYMBOL%s\t%s\n",
2228                                    sym->crc, sym->name, mod->name,
2229                                    sym->is_gpl_only ? "_GPL" : "",
2230                                    sym->namespace);
2231                 }
2232         }
2233         write_buf(&buf, fname);
2234         free(buf.p);
2235 }
2236
2237 static void write_namespace_deps_files(const char *fname)
2238 {
2239         struct module *mod;
2240         struct namespace_list *ns;
2241         struct buffer ns_deps_buf = {};
2242
2243         list_for_each_entry(mod, &modules, list) {
2244
2245                 if (mod->from_dump || list_empty(&mod->missing_namespaces))
2246                         continue;
2247
2248                 buf_printf(&ns_deps_buf, "%s.ko:", mod->name);
2249
2250                 list_for_each_entry(ns, &mod->missing_namespaces, list)
2251                         buf_printf(&ns_deps_buf, " %s", ns->namespace);
2252
2253                 buf_printf(&ns_deps_buf, "\n");
2254         }
2255
2256         write_if_changed(&ns_deps_buf, fname);
2257         free(ns_deps_buf.p);
2258 }
2259
2260 struct dump_list {
2261         struct list_head list;
2262         const char *file;
2263 };
2264
2265 int main(int argc, char **argv)
2266 {
2267         struct module *mod;
2268         char *missing_namespace_deps = NULL;
2269         char *unused_exports_white_list = NULL;
2270         char *dump_write = NULL, *files_source = NULL;
2271         int opt;
2272         LIST_HEAD(dump_lists);
2273         struct dump_list *dl, *dl2;
2274
2275         while ((opt = getopt(argc, argv, "ei:mnT:to:au:WwENd:")) != -1) {
2276                 switch (opt) {
2277                 case 'e':
2278                         external_module = true;
2279                         break;
2280                 case 'i':
2281                         dl = NOFAIL(malloc(sizeof(*dl)));
2282                         dl->file = optarg;
2283                         list_add_tail(&dl->list, &dump_lists);
2284                         break;
2285                 case 'm':
2286                         modversions = true;
2287                         break;
2288                 case 'n':
2289                         ignore_missing_files = true;
2290                         break;
2291                 case 'o':
2292                         dump_write = optarg;
2293                         break;
2294                 case 'a':
2295                         all_versions = true;
2296                         break;
2297                 case 'T':
2298                         files_source = optarg;
2299                         break;
2300                 case 't':
2301                         trim_unused_exports = true;
2302                         break;
2303                 case 'u':
2304                         unused_exports_white_list = optarg;
2305                         break;
2306                 case 'W':
2307                         extra_warn = true;
2308                         break;
2309                 case 'w':
2310                         warn_unresolved = true;
2311                         break;
2312                 case 'E':
2313                         sec_mismatch_warn_only = false;
2314                         break;
2315                 case 'N':
2316                         allow_missing_ns_imports = true;
2317                         break;
2318                 case 'd':
2319                         missing_namespace_deps = optarg;
2320                         break;
2321                 default:
2322                         exit(1);
2323                 }
2324         }
2325
2326         list_for_each_entry_safe(dl, dl2, &dump_lists, list) {
2327                 read_dump(dl->file);
2328                 list_del(&dl->list);
2329                 free(dl);
2330         }
2331
2332         while (optind < argc)
2333                 read_symbols(argv[optind++]);
2334
2335         if (files_source)
2336                 read_symbols_from_files(files_source);
2337
2338         list_for_each_entry(mod, &modules, list) {
2339                 if (mod->from_dump || mod->is_vmlinux)
2340                         continue;
2341
2342                 check_modname_len(mod);
2343                 check_exports(mod);
2344         }
2345
2346         if (unused_exports_white_list)
2347                 handle_white_list_exports(unused_exports_white_list);
2348
2349         list_for_each_entry(mod, &modules, list) {
2350                 if (mod->from_dump)
2351                         continue;
2352
2353                 if (mod->is_vmlinux)
2354                         write_vmlinux_export_c_file(mod);
2355                 else
2356                         write_mod_c_file(mod);
2357         }
2358
2359         if (missing_namespace_deps)
2360                 write_namespace_deps_files(missing_namespace_deps);
2361
2362         if (dump_write)
2363                 write_dump(dump_write);
2364         if (sec_mismatch_count && !sec_mismatch_warn_only)
2365                 error("Section mismatches detected.\n"
2366                       "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");
2367
2368         if (nr_unresolved > MAX_UNRESOLVED_REPORTS)
2369                 warn("suppressed %u unresolved symbol warnings because there were too many)\n",
2370                      nr_unresolved - MAX_UNRESOLVED_REPORTS);
2371
2372         return error_occurred ? 1 : 0;
2373 }