1 /* Postprocess module symbol versions 2 * 3 * Copyright 2003 Kai Germaschewski 4 * Copyright 2002-2004 Rusty Russell, IBM Corporation 5 * Copyright 2006-2008 Sam Ravnborg 6 * Based in part on module-init-tools/depmod.c,file2alias 7 * 8 * This software may be used and distributed according to the terms 9 * of the GNU General Public License, incorporated herein by reference. 10 * 11 * Usage: modpost vmlinux module1.o module2.o ... 12 */ 13 14 #define _GNU_SOURCE 15 #include <stdio.h> 16 #include <ctype.h> 17 #include <string.h> 18 #include <limits.h> 19 #include <stdbool.h> 20 #include <errno.h> 21 #include "modpost.h" 22 #include "../../include/linux/license.h" 23 24 /* Are we using CONFIG_MODVERSIONS? */ 25 static int modversions = 0; 26 /* Warn about undefined symbols? (do so if we have vmlinux) */ 27 static int have_vmlinux = 0; 28 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */ 29 static int all_versions = 0; 30 /* If we are modposting external module set to 1 */ 31 static int external_module = 0; 32 /* Warn about section mismatch in vmlinux if set to 1 */ 33 static int vmlinux_section_warnings = 1; 34 /* Only warn about unresolved symbols */ 35 static int warn_unresolved = 0; 36 /* How a symbol is exported */ 37 static int sec_mismatch_count = 0; 38 static int sec_mismatch_verbose = 1; 39 static int sec_mismatch_fatal = 0; 40 /* ignore missing files */ 41 static int ignore_missing_files; 42 43 enum export { 44 export_plain, export_unused, export_gpl, 45 export_unused_gpl, export_gpl_future, export_unknown 46 }; 47 48 /* In kernel, this size is defined in linux/module.h; 49 * here we use Elf_Addr instead of long for covering cross-compile 50 */ 51 52 #define MODULE_NAME_LEN (64 - sizeof(Elf_Addr)) 53 54 #define PRINTF __attribute__ ((format (printf, 1, 2))) 55 56 PRINTF void fatal(const char *fmt, ...) 57 { 58 va_list arglist; 59 60 fprintf(stderr, "FATAL: "); 61 62 va_start(arglist, fmt); 63 vfprintf(stderr, fmt, arglist); 64 va_end(arglist); 65 66 exit(1); 67 } 68 69 PRINTF void warn(const char *fmt, ...) 70 { 71 va_list arglist; 72 73 fprintf(stderr, "WARNING: "); 74 75 va_start(arglist, fmt); 76 vfprintf(stderr, fmt, arglist); 77 va_end(arglist); 78 } 79 80 PRINTF void merror(const char *fmt, ...) 81 { 82 va_list arglist; 83 84 fprintf(stderr, "ERROR: "); 85 86 va_start(arglist, fmt); 87 vfprintf(stderr, fmt, arglist); 88 va_end(arglist); 89 } 90 91 static inline bool strends(const char *str, const char *postfix) 92 { 93 if (strlen(str) < strlen(postfix)) 94 return false; 95 96 return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0; 97 } 98 99 static int is_vmlinux(const char *modname) 100 { 101 const char *myname; 102 103 myname = strrchr(modname, '/'); 104 if (myname) 105 myname++; 106 else 107 myname = modname; 108 109 return (strcmp(myname, "vmlinux") == 0) || 110 (strcmp(myname, "vmlinux.o") == 0); 111 } 112 113 void *do_nofail(void *ptr, const char *expr) 114 { 115 if (!ptr) 116 fatal("modpost: Memory allocation failure: %s.\n", expr); 117 118 return ptr; 119 } 120 121 /* A list of all modules we processed */ 122 static struct module *modules; 123 124 static struct module *find_module(const char *modname) 125 { 126 struct module *mod; 127 128 for (mod = modules; mod; mod = mod->next) 129 if (strcmp(mod->name, modname) == 0) 130 break; 131 return mod; 132 } 133 134 static struct module *new_module(const char *modname) 135 { 136 struct module *mod; 137 char *p; 138 139 mod = NOFAIL(malloc(sizeof(*mod))); 140 memset(mod, 0, sizeof(*mod)); 141 p = NOFAIL(strdup(modname)); 142 143 /* strip trailing .o */ 144 if (strends(p, ".o")) { 145 p[strlen(p) - 2] = '\0'; 146 mod->is_dot_o = 1; 147 } 148 149 /* add to list */ 150 mod->name = p; 151 mod->gpl_compatible = -1; 152 mod->next = modules; 153 modules = mod; 154 155 return mod; 156 } 157 158 /* A hash of all exported symbols, 159 * struct symbol is also used for lists of unresolved symbols */ 160 161 #define SYMBOL_HASH_SIZE 1024 162 163 struct symbol { 164 struct symbol *next; 165 struct module *module; 166 unsigned int crc; 167 int crc_valid; 168 unsigned int weak:1; 169 unsigned int vmlinux:1; /* 1 if symbol is defined in vmlinux */ 170 unsigned int kernel:1; /* 1 if symbol is from kernel 171 * (only for external modules) **/ 172 unsigned int preloaded:1; /* 1 if symbol from Module.symvers, or crc */ 173 enum export export; /* Type of export */ 174 char name[0]; 175 }; 176 177 static struct symbol *symbolhash[SYMBOL_HASH_SIZE]; 178 179 /* This is based on the hash agorithm from gdbm, via tdb */ 180 static inline unsigned int tdb_hash(const char *name) 181 { 182 unsigned value; /* Used to compute the hash value. */ 183 unsigned i; /* Used to cycle through random values. */ 184 185 /* Set the initial value from the key size. */ 186 for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++) 187 value = (value + (((unsigned char *)name)[i] << (i*5 % 24))); 188 189 return (1103515243 * value + 12345); 190 } 191 192 /** 193 * Allocate a new symbols for use in the hash of exported symbols or 194 * the list of unresolved symbols per module 195 **/ 196 static struct symbol *alloc_symbol(const char *name, unsigned int weak, 197 struct symbol *next) 198 { 199 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1)); 200 201 memset(s, 0, sizeof(*s)); 202 strcpy(s->name, name); 203 s->weak = weak; 204 s->next = next; 205 return s; 206 } 207 208 /* For the hash of exported symbols */ 209 static struct symbol *new_symbol(const char *name, struct module *module, 210 enum export export) 211 { 212 unsigned int hash; 213 struct symbol *new; 214 215 hash = tdb_hash(name) % SYMBOL_HASH_SIZE; 216 new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]); 217 new->module = module; 218 new->export = export; 219 return new; 220 } 221 222 static struct symbol *find_symbol(const char *name) 223 { 224 struct symbol *s; 225 226 /* For our purposes, .foo matches foo. PPC64 needs this. */ 227 if (name[0] == '.') 228 name++; 229 230 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) { 231 if (strcmp(s->name, name) == 0) 232 return s; 233 } 234 return NULL; 235 } 236 237 static const struct { 238 const char *str; 239 enum export export; 240 } export_list[] = { 241 { .str = "EXPORT_SYMBOL", .export = export_plain }, 242 { .str = "EXPORT_UNUSED_SYMBOL", .export = export_unused }, 243 { .str = "EXPORT_SYMBOL_GPL", .export = export_gpl }, 244 { .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl }, 245 { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future }, 246 { .str = "(unknown)", .export = export_unknown }, 247 }; 248 249 250 static const char *export_str(enum export ex) 251 { 252 return export_list[ex].str; 253 } 254 255 static enum export export_no(const char *s) 256 { 257 int i; 258 259 if (!s) 260 return export_unknown; 261 for (i = 0; export_list[i].export != export_unknown; i++) { 262 if (strcmp(export_list[i].str, s) == 0) 263 return export_list[i].export; 264 } 265 return export_unknown; 266 } 267 268 static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr) 269 { 270 return (void *)elf->hdr + 271 elf->sechdrs[elf->secindex_strings].sh_offset + 272 sechdr->sh_name; 273 } 274 275 static const char *sec_name(struct elf_info *elf, int secindex) 276 { 277 return sech_name(elf, &elf->sechdrs[secindex]); 278 } 279 280 #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0) 281 282 static enum export export_from_secname(struct elf_info *elf, unsigned int sec) 283 { 284 const char *secname = sec_name(elf, sec); 285 286 if (strstarts(secname, "___ksymtab+")) 287 return export_plain; 288 else if (strstarts(secname, "___ksymtab_unused+")) 289 return export_unused; 290 else if (strstarts(secname, "___ksymtab_gpl+")) 291 return export_gpl; 292 else if (strstarts(secname, "___ksymtab_unused_gpl+")) 293 return export_unused_gpl; 294 else if (strstarts(secname, "___ksymtab_gpl_future+")) 295 return export_gpl_future; 296 else 297 return export_unknown; 298 } 299 300 static enum export export_from_sec(struct elf_info *elf, unsigned int sec) 301 { 302 if (sec == elf->export_sec) 303 return export_plain; 304 else if (sec == elf->export_unused_sec) 305 return export_unused; 306 else if (sec == elf->export_gpl_sec) 307 return export_gpl; 308 else if (sec == elf->export_unused_gpl_sec) 309 return export_unused_gpl; 310 else if (sec == elf->export_gpl_future_sec) 311 return export_gpl_future; 312 else 313 return export_unknown; 314 } 315 316 /** 317 * Add an exported symbol - it may have already been added without a 318 * CRC, in this case just update the CRC 319 **/ 320 static struct symbol *sym_add_exported(const char *name, struct module *mod, 321 enum export export) 322 { 323 struct symbol *s = find_symbol(name); 324 325 if (!s) { 326 s = new_symbol(name, mod, export); 327 } else { 328 if (!s->preloaded) { 329 warn("%s: '%s' exported twice. Previous export " 330 "was in %s%s\n", mod->name, name, 331 s->module->name, 332 is_vmlinux(s->module->name) ?"":".ko"); 333 } else { 334 /* In case Module.symvers was out of date */ 335 s->module = mod; 336 } 337 } 338 s->preloaded = 0; 339 s->vmlinux = is_vmlinux(mod->name); 340 s->kernel = 0; 341 s->export = export; 342 return s; 343 } 344 345 static void sym_update_crc(const char *name, struct module *mod, 346 unsigned int crc, enum export export) 347 { 348 struct symbol *s = find_symbol(name); 349 350 if (!s) { 351 s = new_symbol(name, mod, export); 352 /* Don't complain when we find it later. */ 353 s->preloaded = 1; 354 } 355 s->crc = crc; 356 s->crc_valid = 1; 357 } 358 359 void *grab_file(const char *filename, unsigned long *size) 360 { 361 struct stat st; 362 void *map = MAP_FAILED; 363 int fd; 364 365 fd = open(filename, O_RDONLY); 366 if (fd < 0) 367 return NULL; 368 if (fstat(fd, &st)) 369 goto failed; 370 371 *size = st.st_size; 372 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0); 373 374 failed: 375 close(fd); 376 if (map == MAP_FAILED) 377 return NULL; 378 return map; 379 } 380 381 /** 382 * Return a copy of the next line in a mmap'ed file. 383 * spaces in the beginning of the line is trimmed away. 384 * Return a pointer to a static buffer. 385 **/ 386 char *get_next_line(unsigned long *pos, void *file, unsigned long size) 387 { 388 static char line[4096]; 389 int skip = 1; 390 size_t len = 0; 391 signed char *p = (signed char *)file + *pos; 392 char *s = line; 393 394 for (; *pos < size ; (*pos)++) { 395 if (skip && isspace(*p)) { 396 p++; 397 continue; 398 } 399 skip = 0; 400 if (*p != '\n' && (*pos < size)) { 401 len++; 402 *s++ = *p++; 403 if (len > 4095) 404 break; /* Too long, stop */ 405 } else { 406 /* End of string */ 407 *s = '\0'; 408 return line; 409 } 410 } 411 /* End of buffer */ 412 return NULL; 413 } 414 415 void release_file(void *file, unsigned long size) 416 { 417 munmap(file, size); 418 } 419 420 static int parse_elf(struct elf_info *info, const char *filename) 421 { 422 unsigned int i; 423 Elf_Ehdr *hdr; 424 Elf_Shdr *sechdrs; 425 Elf_Sym *sym; 426 const char *secstrings; 427 unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U; 428 429 hdr = grab_file(filename, &info->size); 430 if (!hdr) { 431 if (ignore_missing_files) { 432 fprintf(stderr, "%s: %s (ignored)\n", filename, 433 strerror(errno)); 434 return 0; 435 } 436 perror(filename); 437 exit(1); 438 } 439 info->hdr = hdr; 440 if (info->size < sizeof(*hdr)) { 441 /* file too small, assume this is an empty .o file */ 442 return 0; 443 } 444 /* Is this a valid ELF file? */ 445 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) || 446 (hdr->e_ident[EI_MAG1] != ELFMAG1) || 447 (hdr->e_ident[EI_MAG2] != ELFMAG2) || 448 (hdr->e_ident[EI_MAG3] != ELFMAG3)) { 449 /* Not an ELF file - silently ignore it */ 450 return 0; 451 } 452 /* Fix endianness in ELF header */ 453 hdr->e_type = TO_NATIVE(hdr->e_type); 454 hdr->e_machine = TO_NATIVE(hdr->e_machine); 455 hdr->e_version = TO_NATIVE(hdr->e_version); 456 hdr->e_entry = TO_NATIVE(hdr->e_entry); 457 hdr->e_phoff = TO_NATIVE(hdr->e_phoff); 458 hdr->e_shoff = TO_NATIVE(hdr->e_shoff); 459 hdr->e_flags = TO_NATIVE(hdr->e_flags); 460 hdr->e_ehsize = TO_NATIVE(hdr->e_ehsize); 461 hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize); 462 hdr->e_phnum = TO_NATIVE(hdr->e_phnum); 463 hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize); 464 hdr->e_shnum = TO_NATIVE(hdr->e_shnum); 465 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx); 466 sechdrs = (void *)hdr + hdr->e_shoff; 467 info->sechdrs = sechdrs; 468 469 /* Check if file offset is correct */ 470 if (hdr->e_shoff > info->size) { 471 fatal("section header offset=%lu in file '%s' is bigger than " 472 "filesize=%lu\n", (unsigned long)hdr->e_shoff, 473 filename, info->size); 474 return 0; 475 } 476 477 if (hdr->e_shnum == SHN_UNDEF) { 478 /* 479 * There are more than 64k sections, 480 * read count from .sh_size. 481 */ 482 info->num_sections = TO_NATIVE(sechdrs[0].sh_size); 483 } 484 else { 485 info->num_sections = hdr->e_shnum; 486 } 487 if (hdr->e_shstrndx == SHN_XINDEX) { 488 info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link); 489 } 490 else { 491 info->secindex_strings = hdr->e_shstrndx; 492 } 493 494 /* Fix endianness in section headers */ 495 for (i = 0; i < info->num_sections; i++) { 496 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name); 497 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type); 498 sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags); 499 sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr); 500 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset); 501 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size); 502 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link); 503 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info); 504 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign); 505 sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize); 506 } 507 /* Find symbol table. */ 508 secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset; 509 for (i = 1; i < info->num_sections; i++) { 510 const char *secname; 511 int nobits = sechdrs[i].sh_type == SHT_NOBITS; 512 513 if (!nobits && sechdrs[i].sh_offset > info->size) { 514 fatal("%s is truncated. sechdrs[i].sh_offset=%lu > " 515 "sizeof(*hrd)=%zu\n", filename, 516 (unsigned long)sechdrs[i].sh_offset, 517 sizeof(*hdr)); 518 return 0; 519 } 520 secname = secstrings + sechdrs[i].sh_name; 521 if (strcmp(secname, ".modinfo") == 0) { 522 if (nobits) 523 fatal("%s has NOBITS .modinfo\n", filename); 524 info->modinfo = (void *)hdr + sechdrs[i].sh_offset; 525 info->modinfo_len = sechdrs[i].sh_size; 526 } else if (strcmp(secname, "__ksymtab") == 0) 527 info->export_sec = i; 528 else if (strcmp(secname, "__ksymtab_unused") == 0) 529 info->export_unused_sec = i; 530 else if (strcmp(secname, "__ksymtab_gpl") == 0) 531 info->export_gpl_sec = i; 532 else if (strcmp(secname, "__ksymtab_unused_gpl") == 0) 533 info->export_unused_gpl_sec = i; 534 else if (strcmp(secname, "__ksymtab_gpl_future") == 0) 535 info->export_gpl_future_sec = i; 536 537 if (sechdrs[i].sh_type == SHT_SYMTAB) { 538 unsigned int sh_link_idx; 539 symtab_idx = i; 540 info->symtab_start = (void *)hdr + 541 sechdrs[i].sh_offset; 542 info->symtab_stop = (void *)hdr + 543 sechdrs[i].sh_offset + sechdrs[i].sh_size; 544 sh_link_idx = sechdrs[i].sh_link; 545 info->strtab = (void *)hdr + 546 sechdrs[sh_link_idx].sh_offset; 547 } 548 549 /* 32bit section no. table? ("more than 64k sections") */ 550 if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) { 551 symtab_shndx_idx = i; 552 info->symtab_shndx_start = (void *)hdr + 553 sechdrs[i].sh_offset; 554 info->symtab_shndx_stop = (void *)hdr + 555 sechdrs[i].sh_offset + sechdrs[i].sh_size; 556 } 557 } 558 if (!info->symtab_start) 559 fatal("%s has no symtab?\n", filename); 560 561 /* Fix endianness in symbols */ 562 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) { 563 sym->st_shndx = TO_NATIVE(sym->st_shndx); 564 sym->st_name = TO_NATIVE(sym->st_name); 565 sym->st_value = TO_NATIVE(sym->st_value); 566 sym->st_size = TO_NATIVE(sym->st_size); 567 } 568 569 if (symtab_shndx_idx != ~0U) { 570 Elf32_Word *p; 571 if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link) 572 fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n", 573 filename, sechdrs[symtab_shndx_idx].sh_link, 574 symtab_idx); 575 /* Fix endianness */ 576 for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop; 577 p++) 578 *p = TO_NATIVE(*p); 579 } 580 581 return 1; 582 } 583 584 static void parse_elf_finish(struct elf_info *info) 585 { 586 release_file(info->hdr, info->size); 587 } 588 589 static int ignore_undef_symbol(struct elf_info *info, const char *symname) 590 { 591 /* ignore __this_module, it will be resolved shortly */ 592 if (strcmp(symname, "__this_module") == 0) 593 return 1; 594 /* ignore global offset table */ 595 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0) 596 return 1; 597 if (info->hdr->e_machine == EM_PPC) 598 /* Special register function linked on all modules during final link of .ko */ 599 if (strstarts(symname, "_restgpr_") || 600 strstarts(symname, "_savegpr_") || 601 strstarts(symname, "_rest32gpr_") || 602 strstarts(symname, "_save32gpr_") || 603 strstarts(symname, "_restvr_") || 604 strstarts(symname, "_savevr_")) 605 return 1; 606 if (info->hdr->e_machine == EM_PPC64) 607 /* Special register function linked on all modules during final link of .ko */ 608 if (strstarts(symname, "_restgpr0_") || 609 strstarts(symname, "_savegpr0_") || 610 strstarts(symname, "_restvr_") || 611 strstarts(symname, "_savevr_") || 612 strcmp(symname, ".TOC.") == 0) 613 return 1; 614 /* Do not ignore this symbol */ 615 return 0; 616 } 617 618 static void handle_modversions(struct module *mod, struct elf_info *info, 619 Elf_Sym *sym, const char *symname) 620 { 621 unsigned int crc; 622 enum export export; 623 bool is_crc = false; 624 625 if ((!is_vmlinux(mod->name) || mod->is_dot_o) && 626 strstarts(symname, "__ksymtab")) 627 export = export_from_secname(info, get_secindex(info, sym)); 628 else 629 export = export_from_sec(info, get_secindex(info, sym)); 630 631 /* CRC'd symbol */ 632 if (strstarts(symname, "__crc_")) { 633 is_crc = true; 634 crc = (unsigned int) sym->st_value; 635 if (sym->st_shndx != SHN_UNDEF && sym->st_shndx != SHN_ABS) { 636 unsigned int *crcp; 637 638 /* symbol points to the CRC in the ELF object */ 639 crcp = (void *)info->hdr + sym->st_value + 640 info->sechdrs[sym->st_shndx].sh_offset - 641 (info->hdr->e_type != ET_REL ? 642 info->sechdrs[sym->st_shndx].sh_addr : 0); 643 crc = *crcp; 644 } 645 sym_update_crc(symname + strlen("__crc_"), mod, crc, 646 export); 647 } 648 649 switch (sym->st_shndx) { 650 case SHN_COMMON: 651 if (strstarts(symname, "__gnu_lto_")) { 652 /* Should warn here, but modpost runs before the linker */ 653 } else 654 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name); 655 break; 656 case SHN_UNDEF: 657 /* undefined symbol */ 658 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL && 659 ELF_ST_BIND(sym->st_info) != STB_WEAK) 660 break; 661 if (ignore_undef_symbol(info, symname)) 662 break; 663 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */ 664 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER) 665 /* add compatibility with older glibc */ 666 #ifndef STT_SPARC_REGISTER 667 #define STT_SPARC_REGISTER STT_REGISTER 668 #endif 669 if (info->hdr->e_machine == EM_SPARC || 670 info->hdr->e_machine == EM_SPARCV9) { 671 /* Ignore register directives. */ 672 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER) 673 break; 674 if (symname[0] == '.') { 675 char *munged = NOFAIL(strdup(symname)); 676 munged[0] = '_'; 677 munged[1] = toupper(munged[1]); 678 symname = munged; 679 } 680 } 681 #endif 682 683 if (is_crc) { 684 const char *e = is_vmlinux(mod->name) ?"":".ko"; 685 warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n", 686 symname + strlen("__crc_"), mod->name, e); 687 } 688 mod->unres = alloc_symbol(symname, 689 ELF_ST_BIND(sym->st_info) == STB_WEAK, 690 mod->unres); 691 break; 692 default: 693 /* All exported symbols */ 694 if (strstarts(symname, "__ksymtab_")) { 695 sym_add_exported(symname + strlen("__ksymtab_"), mod, 696 export); 697 } 698 if (strcmp(symname, "init_module") == 0) 699 mod->has_init = 1; 700 if (strcmp(symname, "cleanup_module") == 0) 701 mod->has_cleanup = 1; 702 break; 703 } 704 } 705 706 /** 707 * Parse tag=value strings from .modinfo section 708 **/ 709 static char *next_string(char *string, unsigned long *secsize) 710 { 711 /* Skip non-zero chars */ 712 while (string[0]) { 713 string++; 714 if ((*secsize)-- <= 1) 715 return NULL; 716 } 717 718 /* Skip any zero padding. */ 719 while (!string[0]) { 720 string++; 721 if ((*secsize)-- <= 1) 722 return NULL; 723 } 724 return string; 725 } 726 727 static char *get_next_modinfo(struct elf_info *info, const char *tag, 728 char *prev) 729 { 730 char *p; 731 unsigned int taglen = strlen(tag); 732 char *modinfo = info->modinfo; 733 unsigned long size = info->modinfo_len; 734 735 if (prev) { 736 size -= prev - modinfo; 737 modinfo = next_string(prev, &size); 738 } 739 740 for (p = modinfo; p; p = next_string(p, &size)) { 741 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=') 742 return p + taglen + 1; 743 } 744 return NULL; 745 } 746 747 static char *get_modinfo(struct elf_info *info, const char *tag) 748 749 { 750 return get_next_modinfo(info, tag, NULL); 751 } 752 753 /** 754 * Test if string s ends in string sub 755 * return 0 if match 756 **/ 757 static int strrcmp(const char *s, const char *sub) 758 { 759 int slen, sublen; 760 761 if (!s || !sub) 762 return 1; 763 764 slen = strlen(s); 765 sublen = strlen(sub); 766 767 if ((slen == 0) || (sublen == 0)) 768 return 1; 769 770 if (sublen > slen) 771 return 1; 772 773 return memcmp(s + slen - sublen, sub, sublen); 774 } 775 776 static const char *sym_name(struct elf_info *elf, Elf_Sym *sym) 777 { 778 if (sym) 779 return elf->strtab + sym->st_name; 780 else 781 return "(unknown)"; 782 } 783 784 /* The pattern is an array of simple patterns. 785 * "foo" will match an exact string equal to "foo" 786 * "*foo" will match a string that ends with "foo" 787 * "foo*" will match a string that begins with "foo" 788 * "*foo*" will match a string that contains "foo" 789 */ 790 static int match(const char *sym, const char * const pat[]) 791 { 792 const char *p; 793 while (*pat) { 794 p = *pat++; 795 const char *endp = p + strlen(p) - 1; 796 797 /* "*foo*" */ 798 if (*p == '*' && *endp == '*') { 799 char *here, *bare = strndup(p + 1, strlen(p) - 2); 800 801 here = strstr(sym, bare); 802 free(bare); 803 if (here != NULL) 804 return 1; 805 } 806 /* "*foo" */ 807 else if (*p == '*') { 808 if (strrcmp(sym, p + 1) == 0) 809 return 1; 810 } 811 /* "foo*" */ 812 else if (*endp == '*') { 813 if (strncmp(sym, p, strlen(p) - 1) == 0) 814 return 1; 815 } 816 /* no wildcards */ 817 else { 818 if (strcmp(p, sym) == 0) 819 return 1; 820 } 821 } 822 /* no match */ 823 return 0; 824 } 825 826 /* sections that we do not want to do full section mismatch check on */ 827 static const char *const section_white_list[] = 828 { 829 ".comment*", 830 ".debug*", 831 ".cranges", /* sh64 */ 832 ".zdebug*", /* Compressed debug sections. */ 833 ".GCC.command.line", /* record-gcc-switches */ 834 ".mdebug*", /* alpha, score, mips etc. */ 835 ".pdr", /* alpha, score, mips etc. */ 836 ".stab*", 837 ".note*", 838 ".got*", 839 ".toc*", 840 ".xt.prop", /* xtensa */ 841 ".xt.lit", /* xtensa */ 842 ".arcextmap*", /* arc */ 843 ".gnu.linkonce.arcext*", /* arc : modules */ 844 ".cmem*", /* EZchip */ 845 ".fmt_slot*", /* EZchip */ 846 ".gnu.lto*", 847 ".discard.*", 848 NULL 849 }; 850 851 /* 852 * This is used to find sections missing the SHF_ALLOC flag. 853 * The cause of this is often a section specified in assembler 854 * without "ax" / "aw". 855 */ 856 static void check_section(const char *modname, struct elf_info *elf, 857 Elf_Shdr *sechdr) 858 { 859 const char *sec = sech_name(elf, sechdr); 860 861 if (sechdr->sh_type == SHT_PROGBITS && 862 !(sechdr->sh_flags & SHF_ALLOC) && 863 !match(sec, section_white_list)) { 864 warn("%s (%s): unexpected non-allocatable section.\n" 865 "Did you forget to use \"ax\"/\"aw\" in a .S file?\n" 866 "Note that for example <linux/init.h> contains\n" 867 "section definitions for use in .S files.\n\n", 868 modname, sec); 869 } 870 } 871 872 873 874 #define ALL_INIT_DATA_SECTIONS \ 875 ".init.setup", ".init.rodata", ".meminit.rodata", \ 876 ".init.data", ".meminit.data" 877 #define ALL_EXIT_DATA_SECTIONS \ 878 ".exit.data", ".memexit.data" 879 880 #define ALL_INIT_TEXT_SECTIONS \ 881 ".init.text", ".meminit.text" 882 #define ALL_EXIT_TEXT_SECTIONS \ 883 ".exit.text", ".memexit.text" 884 885 #define ALL_PCI_INIT_SECTIONS \ 886 ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \ 887 ".pci_fixup_enable", ".pci_fixup_resume", \ 888 ".pci_fixup_resume_early", ".pci_fixup_suspend" 889 890 #define ALL_XXXINIT_SECTIONS MEM_INIT_SECTIONS 891 #define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS 892 893 #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS 894 #define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS 895 896 #define DATA_SECTIONS ".data", ".data.rel" 897 #define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \ 898 ".kprobes.text", ".cpuidle.text" 899 #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \ 900 ".fixup", ".entry.text", ".exception.text", ".text.*", \ 901 ".coldtext" 902 903 #define INIT_SECTIONS ".init.*" 904 #define MEM_INIT_SECTIONS ".meminit.*" 905 906 #define EXIT_SECTIONS ".exit.*" 907 #define MEM_EXIT_SECTIONS ".memexit.*" 908 909 #define ALL_TEXT_SECTIONS ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \ 910 TEXT_SECTIONS, OTHER_TEXT_SECTIONS 911 912 /* init data sections */ 913 static const char *const init_data_sections[] = 914 { ALL_INIT_DATA_SECTIONS, NULL }; 915 916 /* all init sections */ 917 static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL }; 918 919 /* All init and exit sections (code + data) */ 920 static const char *const init_exit_sections[] = 921 {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL }; 922 923 /* all text sections */ 924 static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL }; 925 926 /* data section */ 927 static const char *const data_sections[] = { DATA_SECTIONS, NULL }; 928 929 930 /* symbols in .data that may refer to init/exit sections */ 931 #define DEFAULT_SYMBOL_WHITE_LIST \ 932 "*driver", \ 933 "*_template", /* scsi uses *_template a lot */ \ 934 "*_timer", /* arm uses ops structures named _timer a lot */ \ 935 "*_sht", /* scsi also used *_sht to some extent */ \ 936 "*_ops", \ 937 "*_probe", \ 938 "*_probe_one", \ 939 "*_console" 940 941 static const char *const head_sections[] = { ".head.text*", NULL }; 942 static const char *const linker_symbols[] = 943 { "__init_begin", "_sinittext", "_einittext", NULL }; 944 static const char *const optim_symbols[] = { "*.constprop.*", NULL }; 945 946 enum mismatch { 947 TEXT_TO_ANY_INIT, 948 DATA_TO_ANY_INIT, 949 TEXT_TO_ANY_EXIT, 950 DATA_TO_ANY_EXIT, 951 XXXINIT_TO_SOME_INIT, 952 XXXEXIT_TO_SOME_EXIT, 953 ANY_INIT_TO_ANY_EXIT, 954 ANY_EXIT_TO_ANY_INIT, 955 EXPORT_TO_INIT_EXIT, 956 EXTABLE_TO_NON_TEXT, 957 }; 958 959 /** 960 * Describe how to match sections on different criterias: 961 * 962 * @fromsec: Array of sections to be matched. 963 * 964 * @bad_tosec: Relocations applied to a section in @fromsec to a section in 965 * this array is forbidden (black-list). Can be empty. 966 * 967 * @good_tosec: Relocations applied to a section in @fromsec must be 968 * targetting sections in this array (white-list). Can be empty. 969 * 970 * @mismatch: Type of mismatch. 971 * 972 * @symbol_white_list: Do not match a relocation to a symbol in this list 973 * even if it is targetting a section in @bad_to_sec. 974 * 975 * @handler: Specific handler to call when a match is found. If NULL, 976 * default_mismatch_handler() will be called. 977 * 978 */ 979 struct sectioncheck { 980 const char *fromsec[20]; 981 const char *bad_tosec[20]; 982 const char *good_tosec[20]; 983 enum mismatch mismatch; 984 const char *symbol_white_list[20]; 985 void (*handler)(const char *modname, struct elf_info *elf, 986 const struct sectioncheck* const mismatch, 987 Elf_Rela *r, Elf_Sym *sym, const char *fromsec); 988 989 }; 990 991 static void extable_mismatch_handler(const char *modname, struct elf_info *elf, 992 const struct sectioncheck* const mismatch, 993 Elf_Rela *r, Elf_Sym *sym, 994 const char *fromsec); 995 996 static const struct sectioncheck sectioncheck[] = { 997 /* Do not reference init/exit code/data from 998 * normal code and data 999 */ 1000 { 1001 .fromsec = { TEXT_SECTIONS, NULL }, 1002 .bad_tosec = { ALL_INIT_SECTIONS, NULL }, 1003 .mismatch = TEXT_TO_ANY_INIT, 1004 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, 1005 }, 1006 { 1007 .fromsec = { DATA_SECTIONS, NULL }, 1008 .bad_tosec = { ALL_XXXINIT_SECTIONS, NULL }, 1009 .mismatch = DATA_TO_ANY_INIT, 1010 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, 1011 }, 1012 { 1013 .fromsec = { DATA_SECTIONS, NULL }, 1014 .bad_tosec = { INIT_SECTIONS, NULL }, 1015 .mismatch = DATA_TO_ANY_INIT, 1016 .symbol_white_list = { 1017 "*_template", "*_timer", "*_sht", "*_ops", 1018 "*_probe", "*_probe_one", "*_console", NULL 1019 }, 1020 }, 1021 { 1022 .fromsec = { TEXT_SECTIONS, NULL }, 1023 .bad_tosec = { ALL_EXIT_SECTIONS, NULL }, 1024 .mismatch = TEXT_TO_ANY_EXIT, 1025 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, 1026 }, 1027 { 1028 .fromsec = { DATA_SECTIONS, NULL }, 1029 .bad_tosec = { ALL_EXIT_SECTIONS, NULL }, 1030 .mismatch = DATA_TO_ANY_EXIT, 1031 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, 1032 }, 1033 /* Do not reference init code/data from meminit code/data */ 1034 { 1035 .fromsec = { ALL_XXXINIT_SECTIONS, NULL }, 1036 .bad_tosec = { INIT_SECTIONS, NULL }, 1037 .mismatch = XXXINIT_TO_SOME_INIT, 1038 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, 1039 }, 1040 /* Do not reference exit code/data from memexit code/data */ 1041 { 1042 .fromsec = { ALL_XXXEXIT_SECTIONS, NULL }, 1043 .bad_tosec = { EXIT_SECTIONS, NULL }, 1044 .mismatch = XXXEXIT_TO_SOME_EXIT, 1045 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, 1046 }, 1047 /* Do not use exit code/data from init code */ 1048 { 1049 .fromsec = { ALL_INIT_SECTIONS, NULL }, 1050 .bad_tosec = { ALL_EXIT_SECTIONS, NULL }, 1051 .mismatch = ANY_INIT_TO_ANY_EXIT, 1052 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, 1053 }, 1054 /* Do not use init code/data from exit code */ 1055 { 1056 .fromsec = { ALL_EXIT_SECTIONS, NULL }, 1057 .bad_tosec = { ALL_INIT_SECTIONS, NULL }, 1058 .mismatch = ANY_EXIT_TO_ANY_INIT, 1059 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, 1060 }, 1061 { 1062 .fromsec = { ALL_PCI_INIT_SECTIONS, NULL }, 1063 .bad_tosec = { INIT_SECTIONS, NULL }, 1064 .mismatch = ANY_INIT_TO_ANY_EXIT, 1065 .symbol_white_list = { NULL }, 1066 }, 1067 /* Do not export init/exit functions or data */ 1068 { 1069 .fromsec = { "__ksymtab*", NULL }, 1070 .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL }, 1071 .mismatch = EXPORT_TO_INIT_EXIT, 1072 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, 1073 }, 1074 { 1075 .fromsec = { "__ex_table", NULL }, 1076 /* If you're adding any new black-listed sections in here, consider 1077 * adding a special 'printer' for them in scripts/check_extable. 1078 */ 1079 .bad_tosec = { ".altinstr_replacement", NULL }, 1080 .good_tosec = {ALL_TEXT_SECTIONS , NULL}, 1081 .mismatch = EXTABLE_TO_NON_TEXT, 1082 .handler = extable_mismatch_handler, 1083 } 1084 }; 1085 1086 static const struct sectioncheck *section_mismatch( 1087 const char *fromsec, const char *tosec) 1088 { 1089 int i; 1090 int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck); 1091 const struct sectioncheck *check = §ioncheck[0]; 1092 1093 /* 1094 * The target section could be the SHT_NUL section when we're 1095 * handling relocations to un-resolved symbols, trying to match it 1096 * doesn't make much sense and causes build failures on parisc 1097 * architectures. 1098 */ 1099 if (*tosec == '\0') 1100 return NULL; 1101 1102 for (i = 0; i < elems; i++) { 1103 if (match(fromsec, check->fromsec)) { 1104 if (check->bad_tosec[0] && match(tosec, check->bad_tosec)) 1105 return check; 1106 if (check->good_tosec[0] && !match(tosec, check->good_tosec)) 1107 return check; 1108 } 1109 check++; 1110 } 1111 return NULL; 1112 } 1113 1114 /** 1115 * Whitelist to allow certain references to pass with no warning. 1116 * 1117 * Pattern 1: 1118 * If a module parameter is declared __initdata and permissions=0 1119 * then this is legal despite the warning generated. 1120 * We cannot see value of permissions here, so just ignore 1121 * this pattern. 1122 * The pattern is identified by: 1123 * tosec = .init.data 1124 * fromsec = .data* 1125 * atsym =__param* 1126 * 1127 * Pattern 1a: 1128 * module_param_call() ops can refer to __init set function if permissions=0 1129 * The pattern is identified by: 1130 * tosec = .init.text 1131 * fromsec = .data* 1132 * atsym = __param_ops_* 1133 * 1134 * Pattern 2: 1135 * Many drivers utilise a *driver container with references to 1136 * add, remove, probe functions etc. 1137 * the pattern is identified by: 1138 * tosec = init or exit section 1139 * fromsec = data section 1140 * atsym = *driver, *_template, *_sht, *_ops, *_probe, 1141 * *probe_one, *_console, *_timer 1142 * 1143 * Pattern 3: 1144 * Whitelist all references from .head.text to any init section 1145 * 1146 * Pattern 4: 1147 * Some symbols belong to init section but still it is ok to reference 1148 * these from non-init sections as these symbols don't have any memory 1149 * allocated for them and symbol address and value are same. So even 1150 * if init section is freed, its ok to reference those symbols. 1151 * For ex. symbols marking the init section boundaries. 1152 * This pattern is identified by 1153 * refsymname = __init_begin, _sinittext, _einittext 1154 * 1155 * Pattern 5: 1156 * GCC may optimize static inlines when fed constant arg(s) resulting 1157 * in functions like cpumask_empty() -- generating an associated symbol 1158 * cpumask_empty.constprop.3 that appears in the audit. If the const that 1159 * is passed in comes from __init, like say nmi_ipi_mask, we get a 1160 * meaningless section warning. May need to add isra symbols too... 1161 * This pattern is identified by 1162 * tosec = init section 1163 * fromsec = text section 1164 * refsymname = *.constprop.* 1165 * 1166 **/ 1167 static int secref_whitelist(const struct sectioncheck *mismatch, 1168 const char *fromsec, const char *fromsym, 1169 const char *tosec, const char *tosym) 1170 { 1171 /* Check for pattern 1 */ 1172 if (match(tosec, init_data_sections) && 1173 match(fromsec, data_sections) && 1174 strstarts(fromsym, "__param")) 1175 return 0; 1176 1177 /* Check for pattern 1a */ 1178 if (strcmp(tosec, ".init.text") == 0 && 1179 match(fromsec, data_sections) && 1180 strstarts(fromsym, "__param_ops_")) 1181 return 0; 1182 1183 /* Check for pattern 2 */ 1184 if (match(tosec, init_exit_sections) && 1185 match(fromsec, data_sections) && 1186 match(fromsym, mismatch->symbol_white_list)) 1187 return 0; 1188 1189 /* Check for pattern 3 */ 1190 if (match(fromsec, head_sections) && 1191 match(tosec, init_sections)) 1192 return 0; 1193 1194 /* Check for pattern 4 */ 1195 if (match(tosym, linker_symbols)) 1196 return 0; 1197 1198 /* Check for pattern 5 */ 1199 if (match(fromsec, text_sections) && 1200 match(tosec, init_sections) && 1201 match(fromsym, optim_symbols)) 1202 return 0; 1203 1204 return 1; 1205 } 1206 1207 static inline int is_arm_mapping_symbol(const char *str) 1208 { 1209 return str[0] == '$' && strchr("axtd", str[1]) 1210 && (str[2] == '\0' || str[2] == '.'); 1211 } 1212 1213 /* 1214 * If there's no name there, ignore it; likewise, ignore it if it's 1215 * one of the magic symbols emitted used by current ARM tools. 1216 * 1217 * Otherwise if find_symbols_between() returns those symbols, they'll 1218 * fail the whitelist tests and cause lots of false alarms ... fixable 1219 * only by merging __exit and __init sections into __text, bloating 1220 * the kernel (which is especially evil on embedded platforms). 1221 */ 1222 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym) 1223 { 1224 const char *name = elf->strtab + sym->st_name; 1225 1226 if (!name || !strlen(name)) 1227 return 0; 1228 return !is_arm_mapping_symbol(name); 1229 } 1230 1231 /** 1232 * Find symbol based on relocation record info. 1233 * In some cases the symbol supplied is a valid symbol so 1234 * return refsym. If st_name != 0 we assume this is a valid symbol. 1235 * In other cases the symbol needs to be looked up in the symbol table 1236 * based on section and address. 1237 * **/ 1238 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr, 1239 Elf_Sym *relsym) 1240 { 1241 Elf_Sym *sym; 1242 Elf_Sym *near = NULL; 1243 Elf64_Sword distance = 20; 1244 Elf64_Sword d; 1245 unsigned int relsym_secindex; 1246 1247 if (relsym->st_name != 0) 1248 return relsym; 1249 1250 relsym_secindex = get_secindex(elf, relsym); 1251 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { 1252 if (get_secindex(elf, sym) != relsym_secindex) 1253 continue; 1254 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION) 1255 continue; 1256 if (!is_valid_name(elf, sym)) 1257 continue; 1258 if (sym->st_value == addr) 1259 return sym; 1260 /* Find a symbol nearby - addr are maybe negative */ 1261 d = sym->st_value - addr; 1262 if (d < 0) 1263 d = addr - sym->st_value; 1264 if (d < distance) { 1265 distance = d; 1266 near = sym; 1267 } 1268 } 1269 /* We need a close match */ 1270 if (distance < 20) 1271 return near; 1272 else 1273 return NULL; 1274 } 1275 1276 /* 1277 * Find symbols before or equal addr and after addr - in the section sec. 1278 * If we find two symbols with equal offset prefer one with a valid name. 1279 * The ELF format may have a better way to detect what type of symbol 1280 * it is, but this works for now. 1281 **/ 1282 static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr, 1283 const char *sec) 1284 { 1285 Elf_Sym *sym; 1286 Elf_Sym *near = NULL; 1287 Elf_Addr distance = ~0; 1288 1289 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { 1290 const char *symsec; 1291 1292 if (is_shndx_special(sym->st_shndx)) 1293 continue; 1294 symsec = sec_name(elf, get_secindex(elf, sym)); 1295 if (strcmp(symsec, sec) != 0) 1296 continue; 1297 if (!is_valid_name(elf, sym)) 1298 continue; 1299 if (sym->st_value <= addr) { 1300 if ((addr - sym->st_value) < distance) { 1301 distance = addr - sym->st_value; 1302 near = sym; 1303 } else if ((addr - sym->st_value) == distance) { 1304 near = sym; 1305 } 1306 } 1307 } 1308 return near; 1309 } 1310 1311 /* 1312 * Convert a section name to the function/data attribute 1313 * .init.text => __init 1314 * .memexitconst => __memconst 1315 * etc. 1316 * 1317 * The memory of returned value has been allocated on a heap. The user of this 1318 * method should free it after usage. 1319 */ 1320 static char *sec2annotation(const char *s) 1321 { 1322 if (match(s, init_exit_sections)) { 1323 char *p = NOFAIL(malloc(20)); 1324 char *r = p; 1325 1326 *p++ = '_'; 1327 *p++ = '_'; 1328 if (*s == '.') 1329 s++; 1330 while (*s && *s != '.') 1331 *p++ = *s++; 1332 *p = '\0'; 1333 if (*s == '.') 1334 s++; 1335 if (strstr(s, "rodata") != NULL) 1336 strcat(p, "const "); 1337 else if (strstr(s, "data") != NULL) 1338 strcat(p, "data "); 1339 else 1340 strcat(p, " "); 1341 return r; 1342 } else { 1343 return NOFAIL(strdup("")); 1344 } 1345 } 1346 1347 static int is_function(Elf_Sym *sym) 1348 { 1349 if (sym) 1350 return ELF_ST_TYPE(sym->st_info) == STT_FUNC; 1351 else 1352 return -1; 1353 } 1354 1355 static void print_section_list(const char * const list[20]) 1356 { 1357 const char *const *s = list; 1358 1359 while (*s) { 1360 fprintf(stderr, "%s", *s); 1361 s++; 1362 if (*s) 1363 fprintf(stderr, ", "); 1364 } 1365 fprintf(stderr, "\n"); 1366 } 1367 1368 static inline void get_pretty_name(int is_func, const char** name, const char** name_p) 1369 { 1370 switch (is_func) { 1371 case 0: *name = "variable"; *name_p = ""; break; 1372 case 1: *name = "function"; *name_p = "()"; break; 1373 default: *name = "(unknown reference)"; *name_p = ""; break; 1374 } 1375 } 1376 1377 /* 1378 * Print a warning about a section mismatch. 1379 * Try to find symbols near it so user can find it. 1380 * Check whitelist before warning - it may be a false positive. 1381 */ 1382 static void report_sec_mismatch(const char *modname, 1383 const struct sectioncheck *mismatch, 1384 const char *fromsec, 1385 unsigned long long fromaddr, 1386 const char *fromsym, 1387 int from_is_func, 1388 const char *tosec, const char *tosym, 1389 int to_is_func) 1390 { 1391 const char *from, *from_p; 1392 const char *to, *to_p; 1393 char *prl_from; 1394 char *prl_to; 1395 1396 sec_mismatch_count++; 1397 if (!sec_mismatch_verbose) 1398 return; 1399 1400 get_pretty_name(from_is_func, &from, &from_p); 1401 get_pretty_name(to_is_func, &to, &to_p); 1402 1403 warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s " 1404 "to the %s %s:%s%s\n", 1405 modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec, 1406 tosym, to_p); 1407 1408 switch (mismatch->mismatch) { 1409 case TEXT_TO_ANY_INIT: 1410 prl_from = sec2annotation(fromsec); 1411 prl_to = sec2annotation(tosec); 1412 fprintf(stderr, 1413 "The function %s%s() references\n" 1414 "the %s %s%s%s.\n" 1415 "This is often because %s lacks a %s\n" 1416 "annotation or the annotation of %s is wrong.\n", 1417 prl_from, fromsym, 1418 to, prl_to, tosym, to_p, 1419 fromsym, prl_to, tosym); 1420 free(prl_from); 1421 free(prl_to); 1422 break; 1423 case DATA_TO_ANY_INIT: { 1424 prl_to = sec2annotation(tosec); 1425 fprintf(stderr, 1426 "The variable %s references\n" 1427 "the %s %s%s%s\n" 1428 "If the reference is valid then annotate the\n" 1429 "variable with __init* or __refdata (see linux/init.h) " 1430 "or name the variable:\n", 1431 fromsym, to, prl_to, tosym, to_p); 1432 print_section_list(mismatch->symbol_white_list); 1433 free(prl_to); 1434 break; 1435 } 1436 case TEXT_TO_ANY_EXIT: 1437 prl_to = sec2annotation(tosec); 1438 fprintf(stderr, 1439 "The function %s() references a %s in an exit section.\n" 1440 "Often the %s %s%s has valid usage outside the exit section\n" 1441 "and the fix is to remove the %sannotation of %s.\n", 1442 fromsym, to, to, tosym, to_p, prl_to, tosym); 1443 free(prl_to); 1444 break; 1445 case DATA_TO_ANY_EXIT: { 1446 prl_to = sec2annotation(tosec); 1447 fprintf(stderr, 1448 "The variable %s references\n" 1449 "the %s %s%s%s\n" 1450 "If the reference is valid then annotate the\n" 1451 "variable with __exit* (see linux/init.h) or " 1452 "name the variable:\n", 1453 fromsym, to, prl_to, tosym, to_p); 1454 print_section_list(mismatch->symbol_white_list); 1455 free(prl_to); 1456 break; 1457 } 1458 case XXXINIT_TO_SOME_INIT: 1459 case XXXEXIT_TO_SOME_EXIT: 1460 prl_from = sec2annotation(fromsec); 1461 prl_to = sec2annotation(tosec); 1462 fprintf(stderr, 1463 "The %s %s%s%s references\n" 1464 "a %s %s%s%s.\n" 1465 "If %s is only used by %s then\n" 1466 "annotate %s with a matching annotation.\n", 1467 from, prl_from, fromsym, from_p, 1468 to, prl_to, tosym, to_p, 1469 tosym, fromsym, tosym); 1470 free(prl_from); 1471 free(prl_to); 1472 break; 1473 case ANY_INIT_TO_ANY_EXIT: 1474 prl_from = sec2annotation(fromsec); 1475 prl_to = sec2annotation(tosec); 1476 fprintf(stderr, 1477 "The %s %s%s%s references\n" 1478 "a %s %s%s%s.\n" 1479 "This is often seen when error handling " 1480 "in the init function\n" 1481 "uses functionality in the exit path.\n" 1482 "The fix is often to remove the %sannotation of\n" 1483 "%s%s so it may be used outside an exit section.\n", 1484 from, prl_from, fromsym, from_p, 1485 to, prl_to, tosym, to_p, 1486 prl_to, tosym, to_p); 1487 free(prl_from); 1488 free(prl_to); 1489 break; 1490 case ANY_EXIT_TO_ANY_INIT: 1491 prl_from = sec2annotation(fromsec); 1492 prl_to = sec2annotation(tosec); 1493 fprintf(stderr, 1494 "The %s %s%s%s references\n" 1495 "a %s %s%s%s.\n" 1496 "This is often seen when error handling " 1497 "in the exit function\n" 1498 "uses functionality in the init path.\n" 1499 "The fix is often to remove the %sannotation of\n" 1500 "%s%s so it may be used outside an init section.\n", 1501 from, prl_from, fromsym, from_p, 1502 to, prl_to, tosym, to_p, 1503 prl_to, tosym, to_p); 1504 free(prl_from); 1505 free(prl_to); 1506 break; 1507 case EXPORT_TO_INIT_EXIT: 1508 prl_to = sec2annotation(tosec); 1509 fprintf(stderr, 1510 "The symbol %s is exported and annotated %s\n" 1511 "Fix this by removing the %sannotation of %s " 1512 "or drop the export.\n", 1513 tosym, prl_to, prl_to, tosym); 1514 free(prl_to); 1515 break; 1516 case EXTABLE_TO_NON_TEXT: 1517 fatal("There's a special handler for this mismatch type, " 1518 "we should never get here."); 1519 break; 1520 } 1521 fprintf(stderr, "\n"); 1522 } 1523 1524 static void default_mismatch_handler(const char *modname, struct elf_info *elf, 1525 const struct sectioncheck* const mismatch, 1526 Elf_Rela *r, Elf_Sym *sym, const char *fromsec) 1527 { 1528 const char *tosec; 1529 Elf_Sym *to; 1530 Elf_Sym *from; 1531 const char *tosym; 1532 const char *fromsym; 1533 1534 from = find_elf_symbol2(elf, r->r_offset, fromsec); 1535 fromsym = sym_name(elf, from); 1536 1537 if (strstarts(fromsym, "reference___initcall")) 1538 return; 1539 1540 tosec = sec_name(elf, get_secindex(elf, sym)); 1541 to = find_elf_symbol(elf, r->r_addend, sym); 1542 tosym = sym_name(elf, to); 1543 1544 /* check whitelist - we may ignore it */ 1545 if (secref_whitelist(mismatch, 1546 fromsec, fromsym, tosec, tosym)) { 1547 report_sec_mismatch(modname, mismatch, 1548 fromsec, r->r_offset, fromsym, 1549 is_function(from), tosec, tosym, 1550 is_function(to)); 1551 } 1552 } 1553 1554 static int is_executable_section(struct elf_info* elf, unsigned int section_index) 1555 { 1556 if (section_index > elf->num_sections) 1557 fatal("section_index is outside elf->num_sections!\n"); 1558 1559 return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR); 1560 } 1561 1562 /* 1563 * We rely on a gross hack in section_rel[a]() calling find_extable_entry_size() 1564 * to know the sizeof(struct exception_table_entry) for the target architecture. 1565 */ 1566 static unsigned int extable_entry_size = 0; 1567 static void find_extable_entry_size(const char* const sec, const Elf_Rela* r) 1568 { 1569 /* 1570 * If we're currently checking the second relocation within __ex_table, 1571 * that relocation offset tells us the offsetof(struct 1572 * exception_table_entry, fixup) which is equal to sizeof(struct 1573 * exception_table_entry) divided by two. We use that to our advantage 1574 * since there's no portable way to get that size as every architecture 1575 * seems to go with different sized types. Not pretty but better than 1576 * hard-coding the size for every architecture.. 1577 */ 1578 if (!extable_entry_size) 1579 extable_entry_size = r->r_offset * 2; 1580 } 1581 1582 static inline bool is_extable_fault_address(Elf_Rela *r) 1583 { 1584 /* 1585 * extable_entry_size is only discovered after we've handled the 1586 * _second_ relocation in __ex_table, so only abort when we're not 1587 * handling the first reloc and extable_entry_size is zero. 1588 */ 1589 if (r->r_offset && extable_entry_size == 0) 1590 fatal("extable_entry size hasn't been discovered!\n"); 1591 1592 return ((r->r_offset == 0) || 1593 (r->r_offset % extable_entry_size == 0)); 1594 } 1595 1596 #define is_second_extable_reloc(Start, Cur, Sec) \ 1597 (((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0)) 1598 1599 static void report_extable_warnings(const char* modname, struct elf_info* elf, 1600 const struct sectioncheck* const mismatch, 1601 Elf_Rela* r, Elf_Sym* sym, 1602 const char* fromsec, const char* tosec) 1603 { 1604 Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec); 1605 const char* fromsym_name = sym_name(elf, fromsym); 1606 Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym); 1607 const char* tosym_name = sym_name(elf, tosym); 1608 const char* from_pretty_name; 1609 const char* from_pretty_name_p; 1610 const char* to_pretty_name; 1611 const char* to_pretty_name_p; 1612 1613 get_pretty_name(is_function(fromsym), 1614 &from_pretty_name, &from_pretty_name_p); 1615 get_pretty_name(is_function(tosym), 1616 &to_pretty_name, &to_pretty_name_p); 1617 1618 warn("%s(%s+0x%lx): Section mismatch in reference" 1619 " from the %s %s%s to the %s %s:%s%s\n", 1620 modname, fromsec, (long)r->r_offset, from_pretty_name, 1621 fromsym_name, from_pretty_name_p, 1622 to_pretty_name, tosec, tosym_name, to_pretty_name_p); 1623 1624 if (!match(tosec, mismatch->bad_tosec) && 1625 is_executable_section(elf, get_secindex(elf, sym))) 1626 fprintf(stderr, 1627 "The relocation at %s+0x%lx references\n" 1628 "section \"%s\" which is not in the list of\n" 1629 "authorized sections. If you're adding a new section\n" 1630 "and/or if this reference is valid, add \"%s\" to the\n" 1631 "list of authorized sections to jump to on fault.\n" 1632 "This can be achieved by adding \"%s\" to \n" 1633 "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n", 1634 fromsec, (long)r->r_offset, tosec, tosec, tosec); 1635 } 1636 1637 static void extable_mismatch_handler(const char* modname, struct elf_info *elf, 1638 const struct sectioncheck* const mismatch, 1639 Elf_Rela* r, Elf_Sym* sym, 1640 const char *fromsec) 1641 { 1642 const char* tosec = sec_name(elf, get_secindex(elf, sym)); 1643 1644 sec_mismatch_count++; 1645 1646 if (sec_mismatch_verbose) 1647 report_extable_warnings(modname, elf, mismatch, r, sym, 1648 fromsec, tosec); 1649 1650 if (match(tosec, mismatch->bad_tosec)) 1651 fatal("The relocation at %s+0x%lx references\n" 1652 "section \"%s\" which is black-listed.\n" 1653 "Something is seriously wrong and should be fixed.\n" 1654 "You might get more information about where this is\n" 1655 "coming from by using scripts/check_extable.sh %s\n", 1656 fromsec, (long)r->r_offset, tosec, modname); 1657 else if (!is_executable_section(elf, get_secindex(elf, sym))) { 1658 if (is_extable_fault_address(r)) 1659 fatal("The relocation at %s+0x%lx references\n" 1660 "section \"%s\" which is not executable, IOW\n" 1661 "it is not possible for the kernel to fault\n" 1662 "at that address. Something is seriously wrong\n" 1663 "and should be fixed.\n", 1664 fromsec, (long)r->r_offset, tosec); 1665 else 1666 fatal("The relocation at %s+0x%lx references\n" 1667 "section \"%s\" which is not executable, IOW\n" 1668 "the kernel will fault if it ever tries to\n" 1669 "jump to it. Something is seriously wrong\n" 1670 "and should be fixed.\n", 1671 fromsec, (long)r->r_offset, tosec); 1672 } 1673 } 1674 1675 static void check_section_mismatch(const char *modname, struct elf_info *elf, 1676 Elf_Rela *r, Elf_Sym *sym, const char *fromsec) 1677 { 1678 const char *tosec = sec_name(elf, get_secindex(elf, sym)); 1679 const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec); 1680 1681 if (mismatch) { 1682 if (mismatch->handler) 1683 mismatch->handler(modname, elf, mismatch, 1684 r, sym, fromsec); 1685 else 1686 default_mismatch_handler(modname, elf, mismatch, 1687 r, sym, fromsec); 1688 } 1689 } 1690 1691 static unsigned int *reloc_location(struct elf_info *elf, 1692 Elf_Shdr *sechdr, Elf_Rela *r) 1693 { 1694 Elf_Shdr *sechdrs = elf->sechdrs; 1695 int section = sechdr->sh_info; 1696 1697 return (void *)elf->hdr + sechdrs[section].sh_offset + 1698 r->r_offset; 1699 } 1700 1701 static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) 1702 { 1703 unsigned int r_typ = ELF_R_TYPE(r->r_info); 1704 unsigned int *location = reloc_location(elf, sechdr, r); 1705 1706 switch (r_typ) { 1707 case R_386_32: 1708 r->r_addend = TO_NATIVE(*location); 1709 break; 1710 case R_386_PC32: 1711 r->r_addend = TO_NATIVE(*location) + 4; 1712 /* For CONFIG_RELOCATABLE=y */ 1713 if (elf->hdr->e_type == ET_EXEC) 1714 r->r_addend += r->r_offset; 1715 break; 1716 } 1717 return 0; 1718 } 1719 1720 #ifndef R_ARM_CALL 1721 #define R_ARM_CALL 28 1722 #endif 1723 #ifndef R_ARM_JUMP24 1724 #define R_ARM_JUMP24 29 1725 #endif 1726 1727 #ifndef R_ARM_THM_CALL 1728 #define R_ARM_THM_CALL 10 1729 #endif 1730 #ifndef R_ARM_THM_JUMP24 1731 #define R_ARM_THM_JUMP24 30 1732 #endif 1733 #ifndef R_ARM_THM_JUMP19 1734 #define R_ARM_THM_JUMP19 51 1735 #endif 1736 1737 static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) 1738 { 1739 unsigned int r_typ = ELF_R_TYPE(r->r_info); 1740 1741 switch (r_typ) { 1742 case R_ARM_ABS32: 1743 /* From ARM ABI: (S + A) | T */ 1744 r->r_addend = (int)(long) 1745 (elf->symtab_start + ELF_R_SYM(r->r_info)); 1746 break; 1747 case R_ARM_PC24: 1748 case R_ARM_CALL: 1749 case R_ARM_JUMP24: 1750 case R_ARM_THM_CALL: 1751 case R_ARM_THM_JUMP24: 1752 case R_ARM_THM_JUMP19: 1753 /* From ARM ABI: ((S + A) | T) - P */ 1754 r->r_addend = (int)(long)(elf->hdr + 1755 sechdr->sh_offset + 1756 (r->r_offset - sechdr->sh_addr)); 1757 break; 1758 default: 1759 return 1; 1760 } 1761 return 0; 1762 } 1763 1764 static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) 1765 { 1766 unsigned int r_typ = ELF_R_TYPE(r->r_info); 1767 unsigned int *location = reloc_location(elf, sechdr, r); 1768 unsigned int inst; 1769 1770 if (r_typ == R_MIPS_HI16) 1771 return 1; /* skip this */ 1772 inst = TO_NATIVE(*location); 1773 switch (r_typ) { 1774 case R_MIPS_LO16: 1775 r->r_addend = inst & 0xffff; 1776 break; 1777 case R_MIPS_26: 1778 r->r_addend = (inst & 0x03ffffff) << 2; 1779 break; 1780 case R_MIPS_32: 1781 r->r_addend = inst; 1782 break; 1783 } 1784 return 0; 1785 } 1786 1787 static void section_rela(const char *modname, struct elf_info *elf, 1788 Elf_Shdr *sechdr) 1789 { 1790 Elf_Sym *sym; 1791 Elf_Rela *rela; 1792 Elf_Rela r; 1793 unsigned int r_sym; 1794 const char *fromsec; 1795 1796 Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset; 1797 Elf_Rela *stop = (void *)start + sechdr->sh_size; 1798 1799 fromsec = sech_name(elf, sechdr); 1800 fromsec += strlen(".rela"); 1801 /* if from section (name) is know good then skip it */ 1802 if (match(fromsec, section_white_list)) 1803 return; 1804 1805 for (rela = start; rela < stop; rela++) { 1806 r.r_offset = TO_NATIVE(rela->r_offset); 1807 #if KERNEL_ELFCLASS == ELFCLASS64 1808 if (elf->hdr->e_machine == EM_MIPS) { 1809 unsigned int r_typ; 1810 r_sym = ELF64_MIPS_R_SYM(rela->r_info); 1811 r_sym = TO_NATIVE(r_sym); 1812 r_typ = ELF64_MIPS_R_TYPE(rela->r_info); 1813 r.r_info = ELF64_R_INFO(r_sym, r_typ); 1814 } else { 1815 r.r_info = TO_NATIVE(rela->r_info); 1816 r_sym = ELF_R_SYM(r.r_info); 1817 } 1818 #else 1819 r.r_info = TO_NATIVE(rela->r_info); 1820 r_sym = ELF_R_SYM(r.r_info); 1821 #endif 1822 r.r_addend = TO_NATIVE(rela->r_addend); 1823 sym = elf->symtab_start + r_sym; 1824 /* Skip special sections */ 1825 if (is_shndx_special(sym->st_shndx)) 1826 continue; 1827 if (is_second_extable_reloc(start, rela, fromsec)) 1828 find_extable_entry_size(fromsec, &r); 1829 check_section_mismatch(modname, elf, &r, sym, fromsec); 1830 } 1831 } 1832 1833 static void section_rel(const char *modname, struct elf_info *elf, 1834 Elf_Shdr *sechdr) 1835 { 1836 Elf_Sym *sym; 1837 Elf_Rel *rel; 1838 Elf_Rela r; 1839 unsigned int r_sym; 1840 const char *fromsec; 1841 1842 Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset; 1843 Elf_Rel *stop = (void *)start + sechdr->sh_size; 1844 1845 fromsec = sech_name(elf, sechdr); 1846 fromsec += strlen(".rel"); 1847 /* if from section (name) is know good then skip it */ 1848 if (match(fromsec, section_white_list)) 1849 return; 1850 1851 for (rel = start; rel < stop; rel++) { 1852 r.r_offset = TO_NATIVE(rel->r_offset); 1853 #if KERNEL_ELFCLASS == ELFCLASS64 1854 if (elf->hdr->e_machine == EM_MIPS) { 1855 unsigned int r_typ; 1856 r_sym = ELF64_MIPS_R_SYM(rel->r_info); 1857 r_sym = TO_NATIVE(r_sym); 1858 r_typ = ELF64_MIPS_R_TYPE(rel->r_info); 1859 r.r_info = ELF64_R_INFO(r_sym, r_typ); 1860 } else { 1861 r.r_info = TO_NATIVE(rel->r_info); 1862 r_sym = ELF_R_SYM(r.r_info); 1863 } 1864 #else 1865 r.r_info = TO_NATIVE(rel->r_info); 1866 r_sym = ELF_R_SYM(r.r_info); 1867 #endif 1868 r.r_addend = 0; 1869 switch (elf->hdr->e_machine) { 1870 case EM_386: 1871 if (addend_386_rel(elf, sechdr, &r)) 1872 continue; 1873 break; 1874 case EM_ARM: 1875 if (addend_arm_rel(elf, sechdr, &r)) 1876 continue; 1877 break; 1878 case EM_MIPS: 1879 if (addend_mips_rel(elf, sechdr, &r)) 1880 continue; 1881 break; 1882 } 1883 sym = elf->symtab_start + r_sym; 1884 /* Skip special sections */ 1885 if (is_shndx_special(sym->st_shndx)) 1886 continue; 1887 if (is_second_extable_reloc(start, rel, fromsec)) 1888 find_extable_entry_size(fromsec, &r); 1889 check_section_mismatch(modname, elf, &r, sym, fromsec); 1890 } 1891 } 1892 1893 /** 1894 * A module includes a number of sections that are discarded 1895 * either when loaded or when used as built-in. 1896 * For loaded modules all functions marked __init and all data 1897 * marked __initdata will be discarded when the module has been initialized. 1898 * Likewise for modules used built-in the sections marked __exit 1899 * are discarded because __exit marked function are supposed to be called 1900 * only when a module is unloaded which never happens for built-in modules. 1901 * The check_sec_ref() function traverses all relocation records 1902 * to find all references to a section that reference a section that will 1903 * be discarded and warns about it. 1904 **/ 1905 static void check_sec_ref(struct module *mod, const char *modname, 1906 struct elf_info *elf) 1907 { 1908 int i; 1909 Elf_Shdr *sechdrs = elf->sechdrs; 1910 1911 /* Walk through all sections */ 1912 for (i = 0; i < elf->num_sections; i++) { 1913 check_section(modname, elf, &elf->sechdrs[i]); 1914 /* We want to process only relocation sections and not .init */ 1915 if (sechdrs[i].sh_type == SHT_RELA) 1916 section_rela(modname, elf, &elf->sechdrs[i]); 1917 else if (sechdrs[i].sh_type == SHT_REL) 1918 section_rel(modname, elf, &elf->sechdrs[i]); 1919 } 1920 } 1921 1922 static char *remove_dot(char *s) 1923 { 1924 size_t n = strcspn(s, "."); 1925 1926 if (n && s[n]) { 1927 size_t m = strspn(s + n + 1, "0123456789"); 1928 if (m && (s[n + m] == '.' || s[n + m] == 0)) 1929 s[n] = 0; 1930 } 1931 return s; 1932 } 1933 1934 static void read_symbols(const char *modname) 1935 { 1936 const char *symname; 1937 char *version; 1938 char *license; 1939 struct module *mod; 1940 struct elf_info info = { }; 1941 Elf_Sym *sym; 1942 1943 if (!parse_elf(&info, modname)) 1944 return; 1945 1946 mod = new_module(modname); 1947 1948 /* When there's no vmlinux, don't print warnings about 1949 * unresolved symbols (since there'll be too many ;) */ 1950 if (is_vmlinux(modname)) { 1951 have_vmlinux = 1; 1952 mod->skip = 1; 1953 } 1954 1955 license = get_modinfo(&info, "license"); 1956 if (!license && !is_vmlinux(modname)) 1957 warn("modpost: missing MODULE_LICENSE() in %s\n" 1958 "see include/linux/module.h for " 1959 "more information\n", modname); 1960 while (license) { 1961 if (license_is_gpl_compatible(license)) 1962 mod->gpl_compatible = 1; 1963 else { 1964 mod->gpl_compatible = 0; 1965 break; 1966 } 1967 license = get_next_modinfo(&info, "license", license); 1968 } 1969 1970 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) { 1971 symname = remove_dot(info.strtab + sym->st_name); 1972 1973 handle_modversions(mod, &info, sym, symname); 1974 handle_moddevtable(mod, &info, sym, symname); 1975 } 1976 if (!is_vmlinux(modname) || vmlinux_section_warnings) 1977 check_sec_ref(mod, modname, &info); 1978 1979 version = get_modinfo(&info, "version"); 1980 if (version) 1981 maybe_frob_rcs_version(modname, version, info.modinfo, 1982 version - (char *)info.hdr); 1983 if (version || (all_versions && !is_vmlinux(modname))) 1984 get_src_version(modname, mod->srcversion, 1985 sizeof(mod->srcversion)-1); 1986 1987 parse_elf_finish(&info); 1988 1989 /* Our trick to get versioning for module struct etc. - it's 1990 * never passed as an argument to an exported function, so 1991 * the automatic versioning doesn't pick it up, but it's really 1992 * important anyhow */ 1993 if (modversions) 1994 mod->unres = alloc_symbol("module_layout", 0, mod->unres); 1995 } 1996 1997 static void read_symbols_from_files(const char *filename) 1998 { 1999 FILE *in = stdin; 2000 char fname[PATH_MAX]; 2001 2002 if (strcmp(filename, "-") != 0) { 2003 in = fopen(filename, "r"); 2004 if (!in) 2005 fatal("Can't open filenames file %s: %m", filename); 2006 } 2007 2008 while (fgets(fname, PATH_MAX, in) != NULL) { 2009 if (strends(fname, "\n")) 2010 fname[strlen(fname)-1] = '\0'; 2011 read_symbols(fname); 2012 } 2013 2014 if (in != stdin) 2015 fclose(in); 2016 } 2017 2018 #define SZ 500 2019 2020 /* We first write the generated file into memory using the 2021 * following helper, then compare to the file on disk and 2022 * only update the later if anything changed */ 2023 2024 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf, 2025 const char *fmt, ...) 2026 { 2027 char tmp[SZ]; 2028 int len; 2029 va_list ap; 2030 2031 va_start(ap, fmt); 2032 len = vsnprintf(tmp, SZ, fmt, ap); 2033 buf_write(buf, tmp, len); 2034 va_end(ap); 2035 } 2036 2037 void buf_write(struct buffer *buf, const char *s, int len) 2038 { 2039 if (buf->size - buf->pos < len) { 2040 buf->size += len + SZ; 2041 buf->p = NOFAIL(realloc(buf->p, buf->size)); 2042 } 2043 strncpy(buf->p + buf->pos, s, len); 2044 buf->pos += len; 2045 } 2046 2047 static void check_for_gpl_usage(enum export exp, const char *m, const char *s) 2048 { 2049 const char *e = is_vmlinux(m) ?"":".ko"; 2050 2051 switch (exp) { 2052 case export_gpl: 2053 fatal("modpost: GPL-incompatible module %s%s " 2054 "uses GPL-only symbol '%s'\n", m, e, s); 2055 break; 2056 case export_unused_gpl: 2057 fatal("modpost: GPL-incompatible module %s%s " 2058 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s); 2059 break; 2060 case export_gpl_future: 2061 warn("modpost: GPL-incompatible module %s%s " 2062 "uses future GPL-only symbol '%s'\n", m, e, s); 2063 break; 2064 case export_plain: 2065 case export_unused: 2066 case export_unknown: 2067 /* ignore */ 2068 break; 2069 } 2070 } 2071 2072 static void check_for_unused(enum export exp, const char *m, const char *s) 2073 { 2074 const char *e = is_vmlinux(m) ?"":".ko"; 2075 2076 switch (exp) { 2077 case export_unused: 2078 case export_unused_gpl: 2079 warn("modpost: module %s%s " 2080 "uses symbol '%s' marked UNUSED\n", m, e, s); 2081 break; 2082 default: 2083 /* ignore */ 2084 break; 2085 } 2086 } 2087 2088 static void check_exports(struct module *mod) 2089 { 2090 struct symbol *s, *exp; 2091 2092 for (s = mod->unres; s; s = s->next) { 2093 const char *basename; 2094 exp = find_symbol(s->name); 2095 if (!exp || exp->module == mod) 2096 continue; 2097 basename = strrchr(mod->name, '/'); 2098 if (basename) 2099 basename++; 2100 else 2101 basename = mod->name; 2102 if (!mod->gpl_compatible) 2103 check_for_gpl_usage(exp->export, basename, exp->name); 2104 check_for_unused(exp->export, basename, exp->name); 2105 } 2106 } 2107 2108 static int check_modname_len(struct module *mod) 2109 { 2110 const char *mod_name; 2111 2112 mod_name = strrchr(mod->name, '/'); 2113 if (mod_name == NULL) 2114 mod_name = mod->name; 2115 else 2116 mod_name++; 2117 if (strlen(mod_name) >= MODULE_NAME_LEN) { 2118 merror("module name is too long [%s.ko]\n", mod->name); 2119 return 1; 2120 } 2121 2122 return 0; 2123 } 2124 2125 /** 2126 * Header for the generated file 2127 **/ 2128 static void add_header(struct buffer *b, struct module *mod) 2129 { 2130 buf_printf(b, "#include <linux/build-salt.h>\n"); 2131 buf_printf(b, "#include <linux/module.h>\n"); 2132 buf_printf(b, "#include <linux/vermagic.h>\n"); 2133 buf_printf(b, "#include <linux/compiler.h>\n"); 2134 buf_printf(b, "\n"); 2135 buf_printf(b, "BUILD_SALT;\n"); 2136 buf_printf(b, "\n"); 2137 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n"); 2138 buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n"); 2139 buf_printf(b, "\n"); 2140 buf_printf(b, "__visible struct module __this_module\n"); 2141 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n"); 2142 buf_printf(b, "\t.name = KBUILD_MODNAME,\n"); 2143 if (mod->has_init) 2144 buf_printf(b, "\t.init = init_module,\n"); 2145 if (mod->has_cleanup) 2146 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n" 2147 "\t.exit = cleanup_module,\n" 2148 "#endif\n"); 2149 buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n"); 2150 buf_printf(b, "};\n"); 2151 } 2152 2153 static void add_intree_flag(struct buffer *b, int is_intree) 2154 { 2155 if (is_intree) 2156 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n"); 2157 } 2158 2159 /* Cannot check for assembler */ 2160 static void add_retpoline(struct buffer *b) 2161 { 2162 buf_printf(b, "\n#ifdef RETPOLINE\n"); 2163 buf_printf(b, "MODULE_INFO(retpoline, \"Y\");\n"); 2164 buf_printf(b, "#endif\n"); 2165 } 2166 2167 static void add_staging_flag(struct buffer *b, const char *name) 2168 { 2169 if (strstarts(name, "drivers/staging")) 2170 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n"); 2171 } 2172 2173 /** 2174 * Record CRCs for unresolved symbols 2175 **/ 2176 static int add_versions(struct buffer *b, struct module *mod) 2177 { 2178 struct symbol *s, *exp; 2179 int err = 0; 2180 2181 for (s = mod->unres; s; s = s->next) { 2182 exp = find_symbol(s->name); 2183 if (!exp || exp->module == mod) { 2184 if (have_vmlinux && !s->weak) { 2185 if (warn_unresolved) { 2186 warn("\"%s\" [%s.ko] undefined!\n", 2187 s->name, mod->name); 2188 } else { 2189 merror("\"%s\" [%s.ko] undefined!\n", 2190 s->name, mod->name); 2191 err = 1; 2192 } 2193 } 2194 continue; 2195 } 2196 s->module = exp->module; 2197 s->crc_valid = exp->crc_valid; 2198 s->crc = exp->crc; 2199 } 2200 2201 if (!modversions) 2202 return err; 2203 2204 buf_printf(b, "\n"); 2205 buf_printf(b, "static const struct modversion_info ____versions[]\n"); 2206 buf_printf(b, "__used\n"); 2207 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n"); 2208 2209 for (s = mod->unres; s; s = s->next) { 2210 if (!s->module) 2211 continue; 2212 if (!s->crc_valid) { 2213 warn("\"%s\" [%s.ko] has no CRC!\n", 2214 s->name, mod->name); 2215 continue; 2216 } 2217 if (strlen(s->name) >= MODULE_NAME_LEN) { 2218 merror("too long symbol \"%s\" [%s.ko]\n", 2219 s->name, mod->name); 2220 err = 1; 2221 break; 2222 } 2223 buf_printf(b, "\t{ %#8x, \"%s\" },\n", 2224 s->crc, s->name); 2225 } 2226 2227 buf_printf(b, "};\n"); 2228 2229 return err; 2230 } 2231 2232 static void add_depends(struct buffer *b, struct module *mod, 2233 struct module *modules) 2234 { 2235 struct symbol *s; 2236 struct module *m; 2237 int first = 1; 2238 2239 for (m = modules; m; m = m->next) 2240 m->seen = is_vmlinux(m->name); 2241 2242 buf_printf(b, "\n"); 2243 buf_printf(b, "static const char __module_depends[]\n"); 2244 buf_printf(b, "__used\n"); 2245 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n"); 2246 buf_printf(b, "\"depends="); 2247 for (s = mod->unres; s; s = s->next) { 2248 const char *p; 2249 if (!s->module) 2250 continue; 2251 2252 if (s->module->seen) 2253 continue; 2254 2255 s->module->seen = 1; 2256 p = strrchr(s->module->name, '/'); 2257 if (p) 2258 p++; 2259 else 2260 p = s->module->name; 2261 buf_printf(b, "%s%s", first ? "" : ",", p); 2262 first = 0; 2263 } 2264 buf_printf(b, "\";\n"); 2265 } 2266 2267 static void add_srcversion(struct buffer *b, struct module *mod) 2268 { 2269 if (mod->srcversion[0]) { 2270 buf_printf(b, "\n"); 2271 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n", 2272 mod->srcversion); 2273 } 2274 } 2275 2276 static void write_if_changed(struct buffer *b, const char *fname) 2277 { 2278 char *tmp; 2279 FILE *file; 2280 struct stat st; 2281 2282 file = fopen(fname, "r"); 2283 if (!file) 2284 goto write; 2285 2286 if (fstat(fileno(file), &st) < 0) 2287 goto close_write; 2288 2289 if (st.st_size != b->pos) 2290 goto close_write; 2291 2292 tmp = NOFAIL(malloc(b->pos)); 2293 if (fread(tmp, 1, b->pos, file) != b->pos) 2294 goto free_write; 2295 2296 if (memcmp(tmp, b->p, b->pos) != 0) 2297 goto free_write; 2298 2299 free(tmp); 2300 fclose(file); 2301 return; 2302 2303 free_write: 2304 free(tmp); 2305 close_write: 2306 fclose(file); 2307 write: 2308 file = fopen(fname, "w"); 2309 if (!file) { 2310 perror(fname); 2311 exit(1); 2312 } 2313 if (fwrite(b->p, 1, b->pos, file) != b->pos) { 2314 perror(fname); 2315 exit(1); 2316 } 2317 fclose(file); 2318 } 2319 2320 /* parse Module.symvers file. line format: 2321 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something] 2322 **/ 2323 static void read_dump(const char *fname, unsigned int kernel) 2324 { 2325 unsigned long size, pos = 0; 2326 void *file = grab_file(fname, &size); 2327 char *line; 2328 2329 if (!file) 2330 /* No symbol versions, silently ignore */ 2331 return; 2332 2333 while ((line = get_next_line(&pos, file, size))) { 2334 char *symname, *modname, *d, *export, *end; 2335 unsigned int crc; 2336 struct module *mod; 2337 struct symbol *s; 2338 2339 if (!(symname = strchr(line, '\t'))) 2340 goto fail; 2341 *symname++ = '\0'; 2342 if (!(modname = strchr(symname, '\t'))) 2343 goto fail; 2344 *modname++ = '\0'; 2345 if ((export = strchr(modname, '\t')) != NULL) 2346 *export++ = '\0'; 2347 if (export && ((end = strchr(export, '\t')) != NULL)) 2348 *end = '\0'; 2349 crc = strtoul(line, &d, 16); 2350 if (*symname == '\0' || *modname == '\0' || *d != '\0') 2351 goto fail; 2352 mod = find_module(modname); 2353 if (!mod) { 2354 if (is_vmlinux(modname)) 2355 have_vmlinux = 1; 2356 mod = new_module(modname); 2357 mod->skip = 1; 2358 } 2359 s = sym_add_exported(symname, mod, export_no(export)); 2360 s->kernel = kernel; 2361 s->preloaded = 1; 2362 sym_update_crc(symname, mod, crc, export_no(export)); 2363 } 2364 release_file(file, size); 2365 return; 2366 fail: 2367 release_file(file, size); 2368 fatal("parse error in symbol dump file\n"); 2369 } 2370 2371 /* For normal builds always dump all symbols. 2372 * For external modules only dump symbols 2373 * that are not read from kernel Module.symvers. 2374 **/ 2375 static int dump_sym(struct symbol *sym) 2376 { 2377 if (!external_module) 2378 return 1; 2379 if (sym->vmlinux || sym->kernel) 2380 return 0; 2381 return 1; 2382 } 2383 2384 static void write_dump(const char *fname) 2385 { 2386 struct buffer buf = { }; 2387 struct symbol *symbol; 2388 int n; 2389 2390 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) { 2391 symbol = symbolhash[n]; 2392 while (symbol) { 2393 if (dump_sym(symbol)) 2394 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n", 2395 symbol->crc, symbol->name, 2396 symbol->module->name, 2397 export_str(symbol->export)); 2398 symbol = symbol->next; 2399 } 2400 } 2401 write_if_changed(&buf, fname); 2402 free(buf.p); 2403 } 2404 2405 struct ext_sym_list { 2406 struct ext_sym_list *next; 2407 const char *file; 2408 }; 2409 2410 int main(int argc, char **argv) 2411 { 2412 struct module *mod; 2413 struct buffer buf = { }; 2414 char *kernel_read = NULL, *module_read = NULL; 2415 char *dump_write = NULL, *files_source = NULL; 2416 int opt; 2417 int err; 2418 struct ext_sym_list *extsym_iter; 2419 struct ext_sym_list *extsym_start = NULL; 2420 2421 while ((opt = getopt(argc, argv, "i:I:e:mnsST:o:awE")) != -1) { 2422 switch (opt) { 2423 case 'i': 2424 kernel_read = optarg; 2425 break; 2426 case 'I': 2427 module_read = optarg; 2428 external_module = 1; 2429 break; 2430 case 'e': 2431 external_module = 1; 2432 extsym_iter = 2433 NOFAIL(malloc(sizeof(*extsym_iter))); 2434 extsym_iter->next = extsym_start; 2435 extsym_iter->file = optarg; 2436 extsym_start = extsym_iter; 2437 break; 2438 case 'm': 2439 modversions = 1; 2440 break; 2441 case 'n': 2442 ignore_missing_files = 1; 2443 break; 2444 case 'o': 2445 dump_write = optarg; 2446 break; 2447 case 'a': 2448 all_versions = 1; 2449 break; 2450 case 's': 2451 vmlinux_section_warnings = 0; 2452 break; 2453 case 'S': 2454 sec_mismatch_verbose = 0; 2455 break; 2456 case 'T': 2457 files_source = optarg; 2458 break; 2459 case 'w': 2460 warn_unresolved = 1; 2461 break; 2462 case 'E': 2463 sec_mismatch_fatal = 1; 2464 break; 2465 default: 2466 exit(1); 2467 } 2468 } 2469 2470 if (kernel_read) 2471 read_dump(kernel_read, 1); 2472 if (module_read) 2473 read_dump(module_read, 0); 2474 while (extsym_start) { 2475 read_dump(extsym_start->file, 0); 2476 extsym_iter = extsym_start->next; 2477 free(extsym_start); 2478 extsym_start = extsym_iter; 2479 } 2480 2481 while (optind < argc) 2482 read_symbols(argv[optind++]); 2483 2484 if (files_source) 2485 read_symbols_from_files(files_source); 2486 2487 for (mod = modules; mod; mod = mod->next) { 2488 if (mod->skip) 2489 continue; 2490 check_exports(mod); 2491 } 2492 2493 err = 0; 2494 2495 for (mod = modules; mod; mod = mod->next) { 2496 char fname[PATH_MAX]; 2497 2498 if (mod->skip) 2499 continue; 2500 2501 buf.pos = 0; 2502 2503 err |= check_modname_len(mod); 2504 add_header(&buf, mod); 2505 add_intree_flag(&buf, !external_module); 2506 add_retpoline(&buf); 2507 add_staging_flag(&buf, mod->name); 2508 err |= add_versions(&buf, mod); 2509 add_depends(&buf, mod, modules); 2510 add_moddevtable(&buf, mod); 2511 add_srcversion(&buf, mod); 2512 2513 sprintf(fname, "%s.mod.c", mod->name); 2514 write_if_changed(&buf, fname); 2515 } 2516 if (dump_write) 2517 write_dump(dump_write); 2518 if (sec_mismatch_count) { 2519 if (!sec_mismatch_verbose) { 2520 warn("modpost: Found %d section mismatch(es).\n" 2521 "To see full details build your kernel with:\n" 2522 "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n", 2523 sec_mismatch_count); 2524 } 2525 if (sec_mismatch_fatal) { 2526 fatal("modpost: Section mismatches detected.\n" 2527 "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n"); 2528 } 2529 } 2530 free(buf.p); 2531 2532 return err; 2533 } 2534