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 = 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 /** 1208 * Find symbol based on relocation record info. 1209 * In some cases the symbol supplied is a valid symbol so 1210 * return refsym. If st_name != 0 we assume this is a valid symbol. 1211 * In other cases the symbol needs to be looked up in the symbol table 1212 * based on section and address. 1213 * **/ 1214 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr, 1215 Elf_Sym *relsym) 1216 { 1217 Elf_Sym *sym; 1218 Elf_Sym *near = NULL; 1219 Elf64_Sword distance = 20; 1220 Elf64_Sword d; 1221 unsigned int relsym_secindex; 1222 1223 if (relsym->st_name != 0) 1224 return relsym; 1225 1226 relsym_secindex = get_secindex(elf, relsym); 1227 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { 1228 if (get_secindex(elf, sym) != relsym_secindex) 1229 continue; 1230 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION) 1231 continue; 1232 if (sym->st_value == addr) 1233 return sym; 1234 /* Find a symbol nearby - addr are maybe negative */ 1235 d = sym->st_value - addr; 1236 if (d < 0) 1237 d = addr - sym->st_value; 1238 if (d < distance) { 1239 distance = d; 1240 near = sym; 1241 } 1242 } 1243 /* We need a close match */ 1244 if (distance < 20) 1245 return near; 1246 else 1247 return NULL; 1248 } 1249 1250 static inline int is_arm_mapping_symbol(const char *str) 1251 { 1252 return str[0] == '$' && strchr("axtd", str[1]) 1253 && (str[2] == '\0' || str[2] == '.'); 1254 } 1255 1256 /* 1257 * If there's no name there, ignore it; likewise, ignore it if it's 1258 * one of the magic symbols emitted used by current ARM tools. 1259 * 1260 * Otherwise if find_symbols_between() returns those symbols, they'll 1261 * fail the whitelist tests and cause lots of false alarms ... fixable 1262 * only by merging __exit and __init sections into __text, bloating 1263 * the kernel (which is especially evil on embedded platforms). 1264 */ 1265 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym) 1266 { 1267 const char *name = elf->strtab + sym->st_name; 1268 1269 if (!name || !strlen(name)) 1270 return 0; 1271 return !is_arm_mapping_symbol(name); 1272 } 1273 1274 /* 1275 * Find symbols before or equal addr and after addr - in the section sec. 1276 * If we find two symbols with equal offset prefer one with a valid name. 1277 * The ELF format may have a better way to detect what type of symbol 1278 * it is, but this works for now. 1279 **/ 1280 static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr, 1281 const char *sec) 1282 { 1283 Elf_Sym *sym; 1284 Elf_Sym *near = NULL; 1285 Elf_Addr distance = ~0; 1286 1287 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { 1288 const char *symsec; 1289 1290 if (is_shndx_special(sym->st_shndx)) 1291 continue; 1292 symsec = sec_name(elf, get_secindex(elf, sym)); 1293 if (strcmp(symsec, sec) != 0) 1294 continue; 1295 if (!is_valid_name(elf, sym)) 1296 continue; 1297 if (sym->st_value <= addr) { 1298 if ((addr - sym->st_value) < distance) { 1299 distance = addr - sym->st_value; 1300 near = sym; 1301 } else if ((addr - sym->st_value) == distance) { 1302 near = sym; 1303 } 1304 } 1305 } 1306 return near; 1307 } 1308 1309 /* 1310 * Convert a section name to the function/data attribute 1311 * .init.text => __init 1312 * .memexitconst => __memconst 1313 * etc. 1314 * 1315 * The memory of returned value has been allocated on a heap. The user of this 1316 * method should free it after usage. 1317 */ 1318 static char *sec2annotation(const char *s) 1319 { 1320 if (match(s, init_exit_sections)) { 1321 char *p = malloc(20); 1322 char *r = p; 1323 1324 *p++ = '_'; 1325 *p++ = '_'; 1326 if (*s == '.') 1327 s++; 1328 while (*s && *s != '.') 1329 *p++ = *s++; 1330 *p = '\0'; 1331 if (*s == '.') 1332 s++; 1333 if (strstr(s, "rodata") != NULL) 1334 strcat(p, "const "); 1335 else if (strstr(s, "data") != NULL) 1336 strcat(p, "data "); 1337 else 1338 strcat(p, " "); 1339 return r; 1340 } else { 1341 return strdup(""); 1342 } 1343 } 1344 1345 static int is_function(Elf_Sym *sym) 1346 { 1347 if (sym) 1348 return ELF_ST_TYPE(sym->st_info) == STT_FUNC; 1349 else 1350 return -1; 1351 } 1352 1353 static void print_section_list(const char * const list[20]) 1354 { 1355 const char *const *s = list; 1356 1357 while (*s) { 1358 fprintf(stderr, "%s", *s); 1359 s++; 1360 if (*s) 1361 fprintf(stderr, ", "); 1362 } 1363 fprintf(stderr, "\n"); 1364 } 1365 1366 static inline void get_pretty_name(int is_func, const char** name, const char** name_p) 1367 { 1368 switch (is_func) { 1369 case 0: *name = "variable"; *name_p = ""; break; 1370 case 1: *name = "function"; *name_p = "()"; break; 1371 default: *name = "(unknown reference)"; *name_p = ""; break; 1372 } 1373 } 1374 1375 /* 1376 * Print a warning about a section mismatch. 1377 * Try to find symbols near it so user can find it. 1378 * Check whitelist before warning - it may be a false positive. 1379 */ 1380 static void report_sec_mismatch(const char *modname, 1381 const struct sectioncheck *mismatch, 1382 const char *fromsec, 1383 unsigned long long fromaddr, 1384 const char *fromsym, 1385 int from_is_func, 1386 const char *tosec, const char *tosym, 1387 int to_is_func) 1388 { 1389 const char *from, *from_p; 1390 const char *to, *to_p; 1391 char *prl_from; 1392 char *prl_to; 1393 1394 sec_mismatch_count++; 1395 if (!sec_mismatch_verbose) 1396 return; 1397 1398 get_pretty_name(from_is_func, &from, &from_p); 1399 get_pretty_name(to_is_func, &to, &to_p); 1400 1401 warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s " 1402 "to the %s %s:%s%s\n", 1403 modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec, 1404 tosym, to_p); 1405 1406 switch (mismatch->mismatch) { 1407 case TEXT_TO_ANY_INIT: 1408 prl_from = sec2annotation(fromsec); 1409 prl_to = sec2annotation(tosec); 1410 fprintf(stderr, 1411 "The function %s%s() references\n" 1412 "the %s %s%s%s.\n" 1413 "This is often because %s lacks a %s\n" 1414 "annotation or the annotation of %s is wrong.\n", 1415 prl_from, fromsym, 1416 to, prl_to, tosym, to_p, 1417 fromsym, prl_to, tosym); 1418 free(prl_from); 1419 free(prl_to); 1420 break; 1421 case DATA_TO_ANY_INIT: { 1422 prl_to = sec2annotation(tosec); 1423 fprintf(stderr, 1424 "The variable %s references\n" 1425 "the %s %s%s%s\n" 1426 "If the reference is valid then annotate the\n" 1427 "variable with __init* or __refdata (see linux/init.h) " 1428 "or name the variable:\n", 1429 fromsym, to, prl_to, tosym, to_p); 1430 print_section_list(mismatch->symbol_white_list); 1431 free(prl_to); 1432 break; 1433 } 1434 case TEXT_TO_ANY_EXIT: 1435 prl_to = sec2annotation(tosec); 1436 fprintf(stderr, 1437 "The function %s() references a %s in an exit section.\n" 1438 "Often the %s %s%s has valid usage outside the exit section\n" 1439 "and the fix is to remove the %sannotation of %s.\n", 1440 fromsym, to, to, tosym, to_p, prl_to, tosym); 1441 free(prl_to); 1442 break; 1443 case DATA_TO_ANY_EXIT: { 1444 prl_to = sec2annotation(tosec); 1445 fprintf(stderr, 1446 "The variable %s references\n" 1447 "the %s %s%s%s\n" 1448 "If the reference is valid then annotate the\n" 1449 "variable with __exit* (see linux/init.h) or " 1450 "name the variable:\n", 1451 fromsym, to, prl_to, tosym, to_p); 1452 print_section_list(mismatch->symbol_white_list); 1453 free(prl_to); 1454 break; 1455 } 1456 case XXXINIT_TO_SOME_INIT: 1457 case XXXEXIT_TO_SOME_EXIT: 1458 prl_from = sec2annotation(fromsec); 1459 prl_to = sec2annotation(tosec); 1460 fprintf(stderr, 1461 "The %s %s%s%s references\n" 1462 "a %s %s%s%s.\n" 1463 "If %s is only used by %s then\n" 1464 "annotate %s with a matching annotation.\n", 1465 from, prl_from, fromsym, from_p, 1466 to, prl_to, tosym, to_p, 1467 tosym, fromsym, tosym); 1468 free(prl_from); 1469 free(prl_to); 1470 break; 1471 case ANY_INIT_TO_ANY_EXIT: 1472 prl_from = sec2annotation(fromsec); 1473 prl_to = sec2annotation(tosec); 1474 fprintf(stderr, 1475 "The %s %s%s%s references\n" 1476 "a %s %s%s%s.\n" 1477 "This is often seen when error handling " 1478 "in the init function\n" 1479 "uses functionality in the exit path.\n" 1480 "The fix is often to remove the %sannotation of\n" 1481 "%s%s so it may be used outside an exit section.\n", 1482 from, prl_from, fromsym, from_p, 1483 to, prl_to, tosym, to_p, 1484 prl_to, tosym, to_p); 1485 free(prl_from); 1486 free(prl_to); 1487 break; 1488 case ANY_EXIT_TO_ANY_INIT: 1489 prl_from = sec2annotation(fromsec); 1490 prl_to = sec2annotation(tosec); 1491 fprintf(stderr, 1492 "The %s %s%s%s references\n" 1493 "a %s %s%s%s.\n" 1494 "This is often seen when error handling " 1495 "in the exit function\n" 1496 "uses functionality in the init path.\n" 1497 "The fix is often to remove the %sannotation of\n" 1498 "%s%s so it may be used outside an init section.\n", 1499 from, prl_from, fromsym, from_p, 1500 to, prl_to, tosym, to_p, 1501 prl_to, tosym, to_p); 1502 free(prl_from); 1503 free(prl_to); 1504 break; 1505 case EXPORT_TO_INIT_EXIT: 1506 prl_to = sec2annotation(tosec); 1507 fprintf(stderr, 1508 "The symbol %s is exported and annotated %s\n" 1509 "Fix this by removing the %sannotation of %s " 1510 "or drop the export.\n", 1511 tosym, prl_to, prl_to, tosym); 1512 free(prl_to); 1513 break; 1514 case EXTABLE_TO_NON_TEXT: 1515 fatal("There's a special handler for this mismatch type, " 1516 "we should never get here."); 1517 break; 1518 } 1519 fprintf(stderr, "\n"); 1520 } 1521 1522 static void default_mismatch_handler(const char *modname, struct elf_info *elf, 1523 const struct sectioncheck* const mismatch, 1524 Elf_Rela *r, Elf_Sym *sym, const char *fromsec) 1525 { 1526 const char *tosec; 1527 Elf_Sym *to; 1528 Elf_Sym *from; 1529 const char *tosym; 1530 const char *fromsym; 1531 1532 from = find_elf_symbol2(elf, r->r_offset, fromsec); 1533 fromsym = sym_name(elf, from); 1534 1535 if (strstarts(fromsym, "reference___initcall")) 1536 return; 1537 1538 tosec = sec_name(elf, get_secindex(elf, sym)); 1539 to = find_elf_symbol(elf, r->r_addend, sym); 1540 tosym = sym_name(elf, to); 1541 1542 /* check whitelist - we may ignore it */ 1543 if (secref_whitelist(mismatch, 1544 fromsec, fromsym, tosec, tosym)) { 1545 report_sec_mismatch(modname, mismatch, 1546 fromsec, r->r_offset, fromsym, 1547 is_function(from), tosec, tosym, 1548 is_function(to)); 1549 } 1550 } 1551 1552 static int is_executable_section(struct elf_info* elf, unsigned int section_index) 1553 { 1554 if (section_index > elf->num_sections) 1555 fatal("section_index is outside elf->num_sections!\n"); 1556 1557 return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR); 1558 } 1559 1560 /* 1561 * We rely on a gross hack in section_rel[a]() calling find_extable_entry_size() 1562 * to know the sizeof(struct exception_table_entry) for the target architecture. 1563 */ 1564 static unsigned int extable_entry_size = 0; 1565 static void find_extable_entry_size(const char* const sec, const Elf_Rela* r) 1566 { 1567 /* 1568 * If we're currently checking the second relocation within __ex_table, 1569 * that relocation offset tells us the offsetof(struct 1570 * exception_table_entry, fixup) which is equal to sizeof(struct 1571 * exception_table_entry) divided by two. We use that to our advantage 1572 * since there's no portable way to get that size as every architecture 1573 * seems to go with different sized types. Not pretty but better than 1574 * hard-coding the size for every architecture.. 1575 */ 1576 if (!extable_entry_size) 1577 extable_entry_size = r->r_offset * 2; 1578 } 1579 1580 static inline bool is_extable_fault_address(Elf_Rela *r) 1581 { 1582 /* 1583 * extable_entry_size is only discovered after we've handled the 1584 * _second_ relocation in __ex_table, so only abort when we're not 1585 * handling the first reloc and extable_entry_size is zero. 1586 */ 1587 if (r->r_offset && extable_entry_size == 0) 1588 fatal("extable_entry size hasn't been discovered!\n"); 1589 1590 return ((r->r_offset == 0) || 1591 (r->r_offset % extable_entry_size == 0)); 1592 } 1593 1594 #define is_second_extable_reloc(Start, Cur, Sec) \ 1595 (((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0)) 1596 1597 static void report_extable_warnings(const char* modname, struct elf_info* elf, 1598 const struct sectioncheck* const mismatch, 1599 Elf_Rela* r, Elf_Sym* sym, 1600 const char* fromsec, const char* tosec) 1601 { 1602 Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec); 1603 const char* fromsym_name = sym_name(elf, fromsym); 1604 Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym); 1605 const char* tosym_name = sym_name(elf, tosym); 1606 const char* from_pretty_name; 1607 const char* from_pretty_name_p; 1608 const char* to_pretty_name; 1609 const char* to_pretty_name_p; 1610 1611 get_pretty_name(is_function(fromsym), 1612 &from_pretty_name, &from_pretty_name_p); 1613 get_pretty_name(is_function(tosym), 1614 &to_pretty_name, &to_pretty_name_p); 1615 1616 warn("%s(%s+0x%lx): Section mismatch in reference" 1617 " from the %s %s%s to the %s %s:%s%s\n", 1618 modname, fromsec, (long)r->r_offset, from_pretty_name, 1619 fromsym_name, from_pretty_name_p, 1620 to_pretty_name, tosec, tosym_name, to_pretty_name_p); 1621 1622 if (!match(tosec, mismatch->bad_tosec) && 1623 is_executable_section(elf, get_secindex(elf, sym))) 1624 fprintf(stderr, 1625 "The relocation at %s+0x%lx references\n" 1626 "section \"%s\" which is not in the list of\n" 1627 "authorized sections. If you're adding a new section\n" 1628 "and/or if this reference is valid, add \"%s\" to the\n" 1629 "list of authorized sections to jump to on fault.\n" 1630 "This can be achieved by adding \"%s\" to \n" 1631 "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n", 1632 fromsec, (long)r->r_offset, tosec, tosec, tosec); 1633 } 1634 1635 static void extable_mismatch_handler(const char* modname, struct elf_info *elf, 1636 const struct sectioncheck* const mismatch, 1637 Elf_Rela* r, Elf_Sym* sym, 1638 const char *fromsec) 1639 { 1640 const char* tosec = sec_name(elf, get_secindex(elf, sym)); 1641 1642 sec_mismatch_count++; 1643 1644 if (sec_mismatch_verbose) 1645 report_extable_warnings(modname, elf, mismatch, r, sym, 1646 fromsec, tosec); 1647 1648 if (match(tosec, mismatch->bad_tosec)) 1649 fatal("The relocation at %s+0x%lx references\n" 1650 "section \"%s\" which is black-listed.\n" 1651 "Something is seriously wrong and should be fixed.\n" 1652 "You might get more information about where this is\n" 1653 "coming from by using scripts/check_extable.sh %s\n", 1654 fromsec, (long)r->r_offset, tosec, modname); 1655 else if (!is_executable_section(elf, get_secindex(elf, sym))) { 1656 if (is_extable_fault_address(r)) 1657 fatal("The relocation at %s+0x%lx references\n" 1658 "section \"%s\" which is not executable, IOW\n" 1659 "it is not possible for the kernel to fault\n" 1660 "at that address. Something is seriously wrong\n" 1661 "and should be fixed.\n", 1662 fromsec, (long)r->r_offset, tosec); 1663 else 1664 fatal("The relocation at %s+0x%lx references\n" 1665 "section \"%s\" which is not executable, IOW\n" 1666 "the kernel will fault if it ever tries to\n" 1667 "jump to it. Something is seriously wrong\n" 1668 "and should be fixed.\n", 1669 fromsec, (long)r->r_offset, tosec); 1670 } 1671 } 1672 1673 static void check_section_mismatch(const char *modname, struct elf_info *elf, 1674 Elf_Rela *r, Elf_Sym *sym, const char *fromsec) 1675 { 1676 const char *tosec = sec_name(elf, get_secindex(elf, sym)); 1677 const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec); 1678 1679 if (mismatch) { 1680 if (mismatch->handler) 1681 mismatch->handler(modname, elf, mismatch, 1682 r, sym, fromsec); 1683 else 1684 default_mismatch_handler(modname, elf, mismatch, 1685 r, sym, fromsec); 1686 } 1687 } 1688 1689 static unsigned int *reloc_location(struct elf_info *elf, 1690 Elf_Shdr *sechdr, Elf_Rela *r) 1691 { 1692 Elf_Shdr *sechdrs = elf->sechdrs; 1693 int section = sechdr->sh_info; 1694 1695 return (void *)elf->hdr + sechdrs[section].sh_offset + 1696 r->r_offset; 1697 } 1698 1699 static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) 1700 { 1701 unsigned int r_typ = ELF_R_TYPE(r->r_info); 1702 unsigned int *location = reloc_location(elf, sechdr, r); 1703 1704 switch (r_typ) { 1705 case R_386_32: 1706 r->r_addend = TO_NATIVE(*location); 1707 break; 1708 case R_386_PC32: 1709 r->r_addend = TO_NATIVE(*location) + 4; 1710 /* For CONFIG_RELOCATABLE=y */ 1711 if (elf->hdr->e_type == ET_EXEC) 1712 r->r_addend += r->r_offset; 1713 break; 1714 } 1715 return 0; 1716 } 1717 1718 #ifndef R_ARM_CALL 1719 #define R_ARM_CALL 28 1720 #endif 1721 #ifndef R_ARM_JUMP24 1722 #define R_ARM_JUMP24 29 1723 #endif 1724 1725 #ifndef R_ARM_THM_CALL 1726 #define R_ARM_THM_CALL 10 1727 #endif 1728 #ifndef R_ARM_THM_JUMP24 1729 #define R_ARM_THM_JUMP24 30 1730 #endif 1731 #ifndef R_ARM_THM_JUMP19 1732 #define R_ARM_THM_JUMP19 51 1733 #endif 1734 1735 static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) 1736 { 1737 unsigned int r_typ = ELF_R_TYPE(r->r_info); 1738 1739 switch (r_typ) { 1740 case R_ARM_ABS32: 1741 /* From ARM ABI: (S + A) | T */ 1742 r->r_addend = (int)(long) 1743 (elf->symtab_start + ELF_R_SYM(r->r_info)); 1744 break; 1745 case R_ARM_PC24: 1746 case R_ARM_CALL: 1747 case R_ARM_JUMP24: 1748 case R_ARM_THM_CALL: 1749 case R_ARM_THM_JUMP24: 1750 case R_ARM_THM_JUMP19: 1751 /* From ARM ABI: ((S + A) | T) - P */ 1752 r->r_addend = (int)(long)(elf->hdr + 1753 sechdr->sh_offset + 1754 (r->r_offset - sechdr->sh_addr)); 1755 break; 1756 default: 1757 return 1; 1758 } 1759 return 0; 1760 } 1761 1762 static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) 1763 { 1764 unsigned int r_typ = ELF_R_TYPE(r->r_info); 1765 unsigned int *location = reloc_location(elf, sechdr, r); 1766 unsigned int inst; 1767 1768 if (r_typ == R_MIPS_HI16) 1769 return 1; /* skip this */ 1770 inst = TO_NATIVE(*location); 1771 switch (r_typ) { 1772 case R_MIPS_LO16: 1773 r->r_addend = inst & 0xffff; 1774 break; 1775 case R_MIPS_26: 1776 r->r_addend = (inst & 0x03ffffff) << 2; 1777 break; 1778 case R_MIPS_32: 1779 r->r_addend = inst; 1780 break; 1781 } 1782 return 0; 1783 } 1784 1785 static void section_rela(const char *modname, struct elf_info *elf, 1786 Elf_Shdr *sechdr) 1787 { 1788 Elf_Sym *sym; 1789 Elf_Rela *rela; 1790 Elf_Rela r; 1791 unsigned int r_sym; 1792 const char *fromsec; 1793 1794 Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset; 1795 Elf_Rela *stop = (void *)start + sechdr->sh_size; 1796 1797 fromsec = sech_name(elf, sechdr); 1798 fromsec += strlen(".rela"); 1799 /* if from section (name) is know good then skip it */ 1800 if (match(fromsec, section_white_list)) 1801 return; 1802 1803 for (rela = start; rela < stop; rela++) { 1804 r.r_offset = TO_NATIVE(rela->r_offset); 1805 #if KERNEL_ELFCLASS == ELFCLASS64 1806 if (elf->hdr->e_machine == EM_MIPS) { 1807 unsigned int r_typ; 1808 r_sym = ELF64_MIPS_R_SYM(rela->r_info); 1809 r_sym = TO_NATIVE(r_sym); 1810 r_typ = ELF64_MIPS_R_TYPE(rela->r_info); 1811 r.r_info = ELF64_R_INFO(r_sym, r_typ); 1812 } else { 1813 r.r_info = TO_NATIVE(rela->r_info); 1814 r_sym = ELF_R_SYM(r.r_info); 1815 } 1816 #else 1817 r.r_info = TO_NATIVE(rela->r_info); 1818 r_sym = ELF_R_SYM(r.r_info); 1819 #endif 1820 r.r_addend = TO_NATIVE(rela->r_addend); 1821 sym = elf->symtab_start + r_sym; 1822 /* Skip special sections */ 1823 if (is_shndx_special(sym->st_shndx)) 1824 continue; 1825 if (is_second_extable_reloc(start, rela, fromsec)) 1826 find_extable_entry_size(fromsec, &r); 1827 check_section_mismatch(modname, elf, &r, sym, fromsec); 1828 } 1829 } 1830 1831 static void section_rel(const char *modname, struct elf_info *elf, 1832 Elf_Shdr *sechdr) 1833 { 1834 Elf_Sym *sym; 1835 Elf_Rel *rel; 1836 Elf_Rela r; 1837 unsigned int r_sym; 1838 const char *fromsec; 1839 1840 Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset; 1841 Elf_Rel *stop = (void *)start + sechdr->sh_size; 1842 1843 fromsec = sech_name(elf, sechdr); 1844 fromsec += strlen(".rel"); 1845 /* if from section (name) is know good then skip it */ 1846 if (match(fromsec, section_white_list)) 1847 return; 1848 1849 for (rel = start; rel < stop; rel++) { 1850 r.r_offset = TO_NATIVE(rel->r_offset); 1851 #if KERNEL_ELFCLASS == ELFCLASS64 1852 if (elf->hdr->e_machine == EM_MIPS) { 1853 unsigned int r_typ; 1854 r_sym = ELF64_MIPS_R_SYM(rel->r_info); 1855 r_sym = TO_NATIVE(r_sym); 1856 r_typ = ELF64_MIPS_R_TYPE(rel->r_info); 1857 r.r_info = ELF64_R_INFO(r_sym, r_typ); 1858 } else { 1859 r.r_info = TO_NATIVE(rel->r_info); 1860 r_sym = ELF_R_SYM(r.r_info); 1861 } 1862 #else 1863 r.r_info = TO_NATIVE(rel->r_info); 1864 r_sym = ELF_R_SYM(r.r_info); 1865 #endif 1866 r.r_addend = 0; 1867 switch (elf->hdr->e_machine) { 1868 case EM_386: 1869 if (addend_386_rel(elf, sechdr, &r)) 1870 continue; 1871 break; 1872 case EM_ARM: 1873 if (addend_arm_rel(elf, sechdr, &r)) 1874 continue; 1875 break; 1876 case EM_MIPS: 1877 if (addend_mips_rel(elf, sechdr, &r)) 1878 continue; 1879 break; 1880 } 1881 sym = elf->symtab_start + r_sym; 1882 /* Skip special sections */ 1883 if (is_shndx_special(sym->st_shndx)) 1884 continue; 1885 if (is_second_extable_reloc(start, rel, fromsec)) 1886 find_extable_entry_size(fromsec, &r); 1887 check_section_mismatch(modname, elf, &r, sym, fromsec); 1888 } 1889 } 1890 1891 /** 1892 * A module includes a number of sections that are discarded 1893 * either when loaded or when used as built-in. 1894 * For loaded modules all functions marked __init and all data 1895 * marked __initdata will be discarded when the module has been initialized. 1896 * Likewise for modules used built-in the sections marked __exit 1897 * are discarded because __exit marked function are supposed to be called 1898 * only when a module is unloaded which never happens for built-in modules. 1899 * The check_sec_ref() function traverses all relocation records 1900 * to find all references to a section that reference a section that will 1901 * be discarded and warns about it. 1902 **/ 1903 static void check_sec_ref(struct module *mod, const char *modname, 1904 struct elf_info *elf) 1905 { 1906 int i; 1907 Elf_Shdr *sechdrs = elf->sechdrs; 1908 1909 /* Walk through all sections */ 1910 for (i = 0; i < elf->num_sections; i++) { 1911 check_section(modname, elf, &elf->sechdrs[i]); 1912 /* We want to process only relocation sections and not .init */ 1913 if (sechdrs[i].sh_type == SHT_RELA) 1914 section_rela(modname, elf, &elf->sechdrs[i]); 1915 else if (sechdrs[i].sh_type == SHT_REL) 1916 section_rel(modname, elf, &elf->sechdrs[i]); 1917 } 1918 } 1919 1920 static char *remove_dot(char *s) 1921 { 1922 size_t n = strcspn(s, "."); 1923 1924 if (n && s[n]) { 1925 size_t m = strspn(s + n + 1, "0123456789"); 1926 if (m && (s[n + m] == '.' || s[n + m] == 0)) 1927 s[n] = 0; 1928 } 1929 return s; 1930 } 1931 1932 static void read_symbols(const char *modname) 1933 { 1934 const char *symname; 1935 char *version; 1936 char *license; 1937 struct module *mod; 1938 struct elf_info info = { }; 1939 Elf_Sym *sym; 1940 1941 if (!parse_elf(&info, modname)) 1942 return; 1943 1944 mod = new_module(modname); 1945 1946 /* When there's no vmlinux, don't print warnings about 1947 * unresolved symbols (since there'll be too many ;) */ 1948 if (is_vmlinux(modname)) { 1949 have_vmlinux = 1; 1950 mod->skip = 1; 1951 } 1952 1953 license = get_modinfo(&info, "license"); 1954 if (!license && !is_vmlinux(modname)) 1955 warn("modpost: missing MODULE_LICENSE() in %s\n" 1956 "see include/linux/module.h for " 1957 "more information\n", modname); 1958 while (license) { 1959 if (license_is_gpl_compatible(license)) 1960 mod->gpl_compatible = 1; 1961 else { 1962 mod->gpl_compatible = 0; 1963 break; 1964 } 1965 license = get_next_modinfo(&info, "license", license); 1966 } 1967 1968 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) { 1969 symname = remove_dot(info.strtab + sym->st_name); 1970 1971 handle_modversions(mod, &info, sym, symname); 1972 handle_moddevtable(mod, &info, sym, symname); 1973 } 1974 if (!is_vmlinux(modname) || vmlinux_section_warnings) 1975 check_sec_ref(mod, modname, &info); 1976 1977 version = get_modinfo(&info, "version"); 1978 if (version) 1979 maybe_frob_rcs_version(modname, version, info.modinfo, 1980 version - (char *)info.hdr); 1981 if (version || (all_versions && !is_vmlinux(modname))) 1982 get_src_version(modname, mod->srcversion, 1983 sizeof(mod->srcversion)-1); 1984 1985 parse_elf_finish(&info); 1986 1987 /* Our trick to get versioning for module struct etc. - it's 1988 * never passed as an argument to an exported function, so 1989 * the automatic versioning doesn't pick it up, but it's really 1990 * important anyhow */ 1991 if (modversions) 1992 mod->unres = alloc_symbol("module_layout", 0, mod->unres); 1993 } 1994 1995 static void read_symbols_from_files(const char *filename) 1996 { 1997 FILE *in = stdin; 1998 char fname[PATH_MAX]; 1999 2000 if (strcmp(filename, "-") != 0) { 2001 in = fopen(filename, "r"); 2002 if (!in) 2003 fatal("Can't open filenames file %s: %m", filename); 2004 } 2005 2006 while (fgets(fname, PATH_MAX, in) != NULL) { 2007 if (strends(fname, "\n")) 2008 fname[strlen(fname)-1] = '\0'; 2009 read_symbols(fname); 2010 } 2011 2012 if (in != stdin) 2013 fclose(in); 2014 } 2015 2016 #define SZ 500 2017 2018 /* We first write the generated file into memory using the 2019 * following helper, then compare to the file on disk and 2020 * only update the later if anything changed */ 2021 2022 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf, 2023 const char *fmt, ...) 2024 { 2025 char tmp[SZ]; 2026 int len; 2027 va_list ap; 2028 2029 va_start(ap, fmt); 2030 len = vsnprintf(tmp, SZ, fmt, ap); 2031 buf_write(buf, tmp, len); 2032 va_end(ap); 2033 } 2034 2035 void buf_write(struct buffer *buf, const char *s, int len) 2036 { 2037 if (buf->size - buf->pos < len) { 2038 buf->size += len + SZ; 2039 buf->p = realloc(buf->p, buf->size); 2040 } 2041 strncpy(buf->p + buf->pos, s, len); 2042 buf->pos += len; 2043 } 2044 2045 static void check_for_gpl_usage(enum export exp, const char *m, const char *s) 2046 { 2047 const char *e = is_vmlinux(m) ?"":".ko"; 2048 2049 switch (exp) { 2050 case export_gpl: 2051 fatal("modpost: GPL-incompatible module %s%s " 2052 "uses GPL-only symbol '%s'\n", m, e, s); 2053 break; 2054 case export_unused_gpl: 2055 fatal("modpost: GPL-incompatible module %s%s " 2056 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s); 2057 break; 2058 case export_gpl_future: 2059 warn("modpost: GPL-incompatible module %s%s " 2060 "uses future GPL-only symbol '%s'\n", m, e, s); 2061 break; 2062 case export_plain: 2063 case export_unused: 2064 case export_unknown: 2065 /* ignore */ 2066 break; 2067 } 2068 } 2069 2070 static void check_for_unused(enum export exp, const char *m, const char *s) 2071 { 2072 const char *e = is_vmlinux(m) ?"":".ko"; 2073 2074 switch (exp) { 2075 case export_unused: 2076 case export_unused_gpl: 2077 warn("modpost: module %s%s " 2078 "uses symbol '%s' marked UNUSED\n", m, e, s); 2079 break; 2080 default: 2081 /* ignore */ 2082 break; 2083 } 2084 } 2085 2086 static void check_exports(struct module *mod) 2087 { 2088 struct symbol *s, *exp; 2089 2090 for (s = mod->unres; s; s = s->next) { 2091 const char *basename; 2092 exp = find_symbol(s->name); 2093 if (!exp || exp->module == mod) 2094 continue; 2095 basename = strrchr(mod->name, '/'); 2096 if (basename) 2097 basename++; 2098 else 2099 basename = mod->name; 2100 if (!mod->gpl_compatible) 2101 check_for_gpl_usage(exp->export, basename, exp->name); 2102 check_for_unused(exp->export, basename, exp->name); 2103 } 2104 } 2105 2106 static int check_modname_len(struct module *mod) 2107 { 2108 const char *mod_name; 2109 2110 mod_name = strrchr(mod->name, '/'); 2111 if (mod_name == NULL) 2112 mod_name = mod->name; 2113 else 2114 mod_name++; 2115 if (strlen(mod_name) >= MODULE_NAME_LEN) { 2116 merror("module name is too long [%s.ko]\n", mod->name); 2117 return 1; 2118 } 2119 2120 return 0; 2121 } 2122 2123 /** 2124 * Header for the generated file 2125 **/ 2126 static void add_header(struct buffer *b, struct module *mod) 2127 { 2128 buf_printf(b, "#include <linux/build-salt.h>\n"); 2129 buf_printf(b, "#include <linux/module.h>\n"); 2130 buf_printf(b, "#include <linux/vermagic.h>\n"); 2131 buf_printf(b, "#include <linux/compiler.h>\n"); 2132 buf_printf(b, "\n"); 2133 buf_printf(b, "BUILD_SALT;\n"); 2134 buf_printf(b, "\n"); 2135 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n"); 2136 buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n"); 2137 buf_printf(b, "\n"); 2138 buf_printf(b, "__visible struct module __this_module\n"); 2139 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n"); 2140 buf_printf(b, "\t.name = KBUILD_MODNAME,\n"); 2141 if (mod->has_init) 2142 buf_printf(b, "\t.init = init_module,\n"); 2143 if (mod->has_cleanup) 2144 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n" 2145 "\t.exit = cleanup_module,\n" 2146 "#endif\n"); 2147 buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n"); 2148 buf_printf(b, "};\n"); 2149 } 2150 2151 static void add_intree_flag(struct buffer *b, int is_intree) 2152 { 2153 if (is_intree) 2154 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n"); 2155 } 2156 2157 /* Cannot check for assembler */ 2158 static void add_retpoline(struct buffer *b) 2159 { 2160 buf_printf(b, "\n#ifdef RETPOLINE\n"); 2161 buf_printf(b, "MODULE_INFO(retpoline, \"Y\");\n"); 2162 buf_printf(b, "#endif\n"); 2163 } 2164 2165 static void add_staging_flag(struct buffer *b, const char *name) 2166 { 2167 if (strstarts(name, "drivers/staging")) 2168 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n"); 2169 } 2170 2171 /** 2172 * Record CRCs for unresolved symbols 2173 **/ 2174 static int add_versions(struct buffer *b, struct module *mod) 2175 { 2176 struct symbol *s, *exp; 2177 int err = 0; 2178 2179 for (s = mod->unres; s; s = s->next) { 2180 exp = find_symbol(s->name); 2181 if (!exp || exp->module == mod) { 2182 if (have_vmlinux && !s->weak) { 2183 if (warn_unresolved) { 2184 warn("\"%s\" [%s.ko] undefined!\n", 2185 s->name, mod->name); 2186 } else { 2187 merror("\"%s\" [%s.ko] undefined!\n", 2188 s->name, mod->name); 2189 err = 1; 2190 } 2191 } 2192 continue; 2193 } 2194 s->module = exp->module; 2195 s->crc_valid = exp->crc_valid; 2196 s->crc = exp->crc; 2197 } 2198 2199 if (!modversions) 2200 return err; 2201 2202 buf_printf(b, "\n"); 2203 buf_printf(b, "static const struct modversion_info ____versions[]\n"); 2204 buf_printf(b, "__used\n"); 2205 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n"); 2206 2207 for (s = mod->unres; s; s = s->next) { 2208 if (!s->module) 2209 continue; 2210 if (!s->crc_valid) { 2211 warn("\"%s\" [%s.ko] has no CRC!\n", 2212 s->name, mod->name); 2213 continue; 2214 } 2215 if (strlen(s->name) >= MODULE_NAME_LEN) { 2216 merror("too long symbol \"%s\" [%s.ko]\n", 2217 s->name, mod->name); 2218 err = 1; 2219 break; 2220 } 2221 buf_printf(b, "\t{ %#8x, \"%s\" },\n", 2222 s->crc, s->name); 2223 } 2224 2225 buf_printf(b, "};\n"); 2226 2227 return err; 2228 } 2229 2230 static void add_depends(struct buffer *b, struct module *mod, 2231 struct module *modules) 2232 { 2233 struct symbol *s; 2234 struct module *m; 2235 int first = 1; 2236 2237 for (m = modules; m; m = m->next) 2238 m->seen = is_vmlinux(m->name); 2239 2240 buf_printf(b, "\n"); 2241 buf_printf(b, "static const char __module_depends[]\n"); 2242 buf_printf(b, "__used\n"); 2243 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n"); 2244 buf_printf(b, "\"depends="); 2245 for (s = mod->unres; s; s = s->next) { 2246 const char *p; 2247 if (!s->module) 2248 continue; 2249 2250 if (s->module->seen) 2251 continue; 2252 2253 s->module->seen = 1; 2254 p = strrchr(s->module->name, '/'); 2255 if (p) 2256 p++; 2257 else 2258 p = s->module->name; 2259 buf_printf(b, "%s%s", first ? "" : ",", p); 2260 first = 0; 2261 } 2262 buf_printf(b, "\";\n"); 2263 } 2264 2265 static void add_srcversion(struct buffer *b, struct module *mod) 2266 { 2267 if (mod->srcversion[0]) { 2268 buf_printf(b, "\n"); 2269 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n", 2270 mod->srcversion); 2271 } 2272 } 2273 2274 static void write_if_changed(struct buffer *b, const char *fname) 2275 { 2276 char *tmp; 2277 FILE *file; 2278 struct stat st; 2279 2280 file = fopen(fname, "r"); 2281 if (!file) 2282 goto write; 2283 2284 if (fstat(fileno(file), &st) < 0) 2285 goto close_write; 2286 2287 if (st.st_size != b->pos) 2288 goto close_write; 2289 2290 tmp = NOFAIL(malloc(b->pos)); 2291 if (fread(tmp, 1, b->pos, file) != b->pos) 2292 goto free_write; 2293 2294 if (memcmp(tmp, b->p, b->pos) != 0) 2295 goto free_write; 2296 2297 free(tmp); 2298 fclose(file); 2299 return; 2300 2301 free_write: 2302 free(tmp); 2303 close_write: 2304 fclose(file); 2305 write: 2306 file = fopen(fname, "w"); 2307 if (!file) { 2308 perror(fname); 2309 exit(1); 2310 } 2311 if (fwrite(b->p, 1, b->pos, file) != b->pos) { 2312 perror(fname); 2313 exit(1); 2314 } 2315 fclose(file); 2316 } 2317 2318 /* parse Module.symvers file. line format: 2319 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something] 2320 **/ 2321 static void read_dump(const char *fname, unsigned int kernel) 2322 { 2323 unsigned long size, pos = 0; 2324 void *file = grab_file(fname, &size); 2325 char *line; 2326 2327 if (!file) 2328 /* No symbol versions, silently ignore */ 2329 return; 2330 2331 while ((line = get_next_line(&pos, file, size))) { 2332 char *symname, *modname, *d, *export, *end; 2333 unsigned int crc; 2334 struct module *mod; 2335 struct symbol *s; 2336 2337 if (!(symname = strchr(line, '\t'))) 2338 goto fail; 2339 *symname++ = '\0'; 2340 if (!(modname = strchr(symname, '\t'))) 2341 goto fail; 2342 *modname++ = '\0'; 2343 if ((export = strchr(modname, '\t')) != NULL) 2344 *export++ = '\0'; 2345 if (export && ((end = strchr(export, '\t')) != NULL)) 2346 *end = '\0'; 2347 crc = strtoul(line, &d, 16); 2348 if (*symname == '\0' || *modname == '\0' || *d != '\0') 2349 goto fail; 2350 mod = find_module(modname); 2351 if (!mod) { 2352 if (is_vmlinux(modname)) 2353 have_vmlinux = 1; 2354 mod = new_module(modname); 2355 mod->skip = 1; 2356 } 2357 s = sym_add_exported(symname, mod, export_no(export)); 2358 s->kernel = kernel; 2359 s->preloaded = 1; 2360 sym_update_crc(symname, mod, crc, export_no(export)); 2361 } 2362 release_file(file, size); 2363 return; 2364 fail: 2365 release_file(file, size); 2366 fatal("parse error in symbol dump file\n"); 2367 } 2368 2369 /* For normal builds always dump all symbols. 2370 * For external modules only dump symbols 2371 * that are not read from kernel Module.symvers. 2372 **/ 2373 static int dump_sym(struct symbol *sym) 2374 { 2375 if (!external_module) 2376 return 1; 2377 if (sym->vmlinux || sym->kernel) 2378 return 0; 2379 return 1; 2380 } 2381 2382 static void write_dump(const char *fname) 2383 { 2384 struct buffer buf = { }; 2385 struct symbol *symbol; 2386 int n; 2387 2388 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) { 2389 symbol = symbolhash[n]; 2390 while (symbol) { 2391 if (dump_sym(symbol)) 2392 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n", 2393 symbol->crc, symbol->name, 2394 symbol->module->name, 2395 export_str(symbol->export)); 2396 symbol = symbol->next; 2397 } 2398 } 2399 write_if_changed(&buf, fname); 2400 free(buf.p); 2401 } 2402 2403 struct ext_sym_list { 2404 struct ext_sym_list *next; 2405 const char *file; 2406 }; 2407 2408 int main(int argc, char **argv) 2409 { 2410 struct module *mod; 2411 struct buffer buf = { }; 2412 char *kernel_read = NULL, *module_read = NULL; 2413 char *dump_write = NULL, *files_source = NULL; 2414 int opt; 2415 int err; 2416 struct ext_sym_list *extsym_iter; 2417 struct ext_sym_list *extsym_start = NULL; 2418 2419 while ((opt = getopt(argc, argv, "i:I:e:mnsST:o:awM:K:E")) != -1) { 2420 switch (opt) { 2421 case 'i': 2422 kernel_read = optarg; 2423 break; 2424 case 'I': 2425 module_read = optarg; 2426 external_module = 1; 2427 break; 2428 case 'e': 2429 external_module = 1; 2430 extsym_iter = 2431 NOFAIL(malloc(sizeof(*extsym_iter))); 2432 extsym_iter->next = extsym_start; 2433 extsym_iter->file = optarg; 2434 extsym_start = extsym_iter; 2435 break; 2436 case 'm': 2437 modversions = 1; 2438 break; 2439 case 'n': 2440 ignore_missing_files = 1; 2441 break; 2442 case 'o': 2443 dump_write = optarg; 2444 break; 2445 case 'a': 2446 all_versions = 1; 2447 break; 2448 case 's': 2449 vmlinux_section_warnings = 0; 2450 break; 2451 case 'S': 2452 sec_mismatch_verbose = 0; 2453 break; 2454 case 'T': 2455 files_source = optarg; 2456 break; 2457 case 'w': 2458 warn_unresolved = 1; 2459 break; 2460 case 'E': 2461 sec_mismatch_fatal = 1; 2462 break; 2463 default: 2464 exit(1); 2465 } 2466 } 2467 2468 if (kernel_read) 2469 read_dump(kernel_read, 1); 2470 if (module_read) 2471 read_dump(module_read, 0); 2472 while (extsym_start) { 2473 read_dump(extsym_start->file, 0); 2474 extsym_iter = extsym_start->next; 2475 free(extsym_start); 2476 extsym_start = extsym_iter; 2477 } 2478 2479 while (optind < argc) 2480 read_symbols(argv[optind++]); 2481 2482 if (files_source) 2483 read_symbols_from_files(files_source); 2484 2485 for (mod = modules; mod; mod = mod->next) { 2486 if (mod->skip) 2487 continue; 2488 check_exports(mod); 2489 } 2490 2491 err = 0; 2492 2493 for (mod = modules; mod; mod = mod->next) { 2494 char fname[PATH_MAX]; 2495 2496 if (mod->skip) 2497 continue; 2498 2499 buf.pos = 0; 2500 2501 err |= check_modname_len(mod); 2502 add_header(&buf, mod); 2503 add_intree_flag(&buf, !external_module); 2504 add_retpoline(&buf); 2505 add_staging_flag(&buf, mod->name); 2506 err |= add_versions(&buf, mod); 2507 add_depends(&buf, mod, modules); 2508 add_moddevtable(&buf, mod); 2509 add_srcversion(&buf, mod); 2510 2511 sprintf(fname, "%s.mod.c", mod->name); 2512 write_if_changed(&buf, fname); 2513 } 2514 if (dump_write) 2515 write_dump(dump_write); 2516 if (sec_mismatch_count) { 2517 if (!sec_mismatch_verbose) { 2518 warn("modpost: Found %d section mismatch(es).\n" 2519 "To see full details build your kernel with:\n" 2520 "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n", 2521 sec_mismatch_count); 2522 } 2523 if (sec_mismatch_fatal) { 2524 fatal("modpost: Section mismatches detected.\n" 2525 "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n"); 2526 } 2527 } 2528 free(buf.p); 2529 2530 return err; 2531 } 2532