1 /* Postprocess module symbol versions
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
8 * This software may be used and distributed according to the terms
9 * of the GNU General Public License, incorporated herein by reference.
11 * Usage: modpost vmlinux module1.o module2.o ...
22 #include "../../include/linux/license.h"
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 /* Only warn about unresolved symbols */
33 static int warn_unresolved = 0;
34 /* How a symbol is exported */
35 static int sec_mismatch_count = 0;
36 static int sec_mismatch_warn_only = true;
37 /* ignore missing files */
38 static int ignore_missing_files;
39 /* If set to 1, only warn (instead of error) about missing ns imports */
40 static int allow_missing_ns_imports;
42 static bool error_occurred;
50 /* In kernel, this size is defined in linux/module.h;
51 * here we use Elf_Addr instead of long for covering cross-compile
54 #define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
56 void __attribute__((format(printf, 2, 3)))
57 modpost_log(enum loglevel loglevel, const char *fmt, ...)
63 fprintf(stderr, "WARNING: ");
66 fprintf(stderr, "ERROR: ");
69 fprintf(stderr, "FATAL: ");
71 default: /* invalid loglevel, ignore */
75 fprintf(stderr, "modpost: ");
77 va_start(arglist, fmt);
78 vfprintf(stderr, fmt, arglist);
81 if (loglevel == LOG_FATAL)
83 if (loglevel == LOG_ERROR)
84 error_occurred = true;
87 void *do_nofail(void *ptr, const char *expr)
90 fatal("Memory allocation failure: %s.\n", expr);
95 char *read_text_file(const char *filename)
102 fd = open(filename, O_RDONLY);
108 if (fstat(fd, &st) < 0) {
113 buf = NOFAIL(malloc(st.st_size + 1));
120 bytes_read = read(fd, buf, nbytes);
121 if (bytes_read < 0) {
126 nbytes -= bytes_read;
128 buf[st.st_size] = '\0';
135 char *get_line(char **stringp)
137 char *orig = *stringp, *next;
139 /* do not return the unwanted extra line at EOF */
140 if (!orig || *orig == '\0')
143 /* don't use strsep here, it is not available everywhere */
144 next = strchr(orig, '\n');
153 /* A list of all modules we processed */
154 static struct module *modules;
156 static struct module *find_module(const char *modname)
160 for (mod = modules; mod; mod = mod->next)
161 if (strcmp(mod->name, modname) == 0)
166 static struct module *new_module(const char *modname)
170 mod = NOFAIL(malloc(sizeof(*mod) + strlen(modname) + 1));
171 memset(mod, 0, sizeof(*mod));
174 strcpy(mod->name, modname);
175 mod->is_vmlinux = (strcmp(modname, "vmlinux") == 0);
176 mod->gpl_compatible = -1;
186 /* A hash of all exported symbols,
187 * struct symbol is also used for lists of unresolved symbols */
189 #define SYMBOL_HASH_SIZE 1024
193 struct module *module;
198 unsigned int is_static:1; /* 1 if symbol is not global */
199 enum export export; /* Type of export */
203 static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
205 /* This is based on the hash agorithm from gdbm, via tdb */
206 static inline unsigned int tdb_hash(const char *name)
208 unsigned value; /* Used to compute the hash value. */
209 unsigned i; /* Used to cycle through random values. */
211 /* Set the initial value from the key size. */
212 for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
213 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
215 return (1103515243 * value + 12345);
219 * Allocate a new symbols for use in the hash of exported symbols or
220 * the list of unresolved symbols per module
222 static struct symbol *alloc_symbol(const char *name, unsigned int weak,
225 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
227 memset(s, 0, sizeof(*s));
228 strcpy(s->name, name);
235 /* For the hash of exported symbols */
236 static struct symbol *new_symbol(const char *name, struct module *module,
241 hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
242 symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
244 return symbolhash[hash];
247 static struct symbol *find_symbol(const char *name)
251 /* For our purposes, .foo matches foo. PPC64 needs this. */
255 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
256 if (strcmp(s->name, name) == 0)
262 static bool contains_namespace(struct namespace_list *list,
263 const char *namespace)
265 for (; list; list = list->next)
266 if (!strcmp(list->namespace, namespace))
272 static void add_namespace(struct namespace_list **list, const char *namespace)
274 struct namespace_list *ns_entry;
276 if (!contains_namespace(*list, namespace)) {
277 ns_entry = NOFAIL(malloc(sizeof(struct namespace_list) +
278 strlen(namespace) + 1));
279 strcpy(ns_entry->namespace, namespace);
280 ns_entry->next = *list;
285 static bool module_imports_namespace(struct module *module,
286 const char *namespace)
288 return contains_namespace(module->imported_namespaces, namespace);
291 static const struct {
295 { .str = "EXPORT_SYMBOL", .export = export_plain },
296 { .str = "EXPORT_SYMBOL_GPL", .export = export_gpl },
297 { .str = "(unknown)", .export = export_unknown },
301 static const char *export_str(enum export ex)
303 return export_list[ex].str;
306 static enum export export_no(const char *s)
311 return export_unknown;
312 for (i = 0; export_list[i].export != export_unknown; i++) {
313 if (strcmp(export_list[i].str, s) == 0)
314 return export_list[i].export;
316 return export_unknown;
319 static void *sym_get_data_by_offset(const struct elf_info *info,
320 unsigned int secindex, unsigned long offset)
322 Elf_Shdr *sechdr = &info->sechdrs[secindex];
324 if (info->hdr->e_type != ET_REL)
325 offset -= sechdr->sh_addr;
327 return (void *)info->hdr + sechdr->sh_offset + offset;
330 static void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym)
332 return sym_get_data_by_offset(info, get_secindex(info, sym),
336 static const char *sech_name(const struct elf_info *info, Elf_Shdr *sechdr)
338 return sym_get_data_by_offset(info, info->secindex_strings,
342 static const char *sec_name(const struct elf_info *info, int secindex)
344 return sech_name(info, &info->sechdrs[secindex]);
347 #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)
349 static enum export export_from_secname(struct elf_info *elf, unsigned int sec)
351 const char *secname = sec_name(elf, sec);
353 if (strstarts(secname, "___ksymtab+"))
355 else if (strstarts(secname, "___ksymtab_gpl+"))
358 return export_unknown;
361 static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
363 if (sec == elf->export_sec)
365 else if (sec == elf->export_gpl_sec)
368 return export_unknown;
371 static const char *namespace_from_kstrtabns(const struct elf_info *info,
374 const char *value = sym_get_data(info, sym);
375 return value[0] ? value : NULL;
378 static void sym_update_namespace(const char *symname, const char *namespace)
380 struct symbol *s = find_symbol(symname);
383 * That symbol should have been created earlier and thus this is
384 * actually an assertion.
387 error("Could not update namespace(%s) for symbol %s\n",
394 namespace && namespace[0] ? NOFAIL(strdup(namespace)) : NULL;
398 * Add an exported symbol - it may have already been added without a
399 * CRC, in this case just update the CRC
401 static struct symbol *sym_add_exported(const char *name, struct module *mod,
404 struct symbol *s = find_symbol(name);
407 s = new_symbol(name, mod, export);
408 } else if (!external_module || s->module->is_vmlinux ||
410 warn("%s: '%s' exported twice. Previous export was in %s%s\n",
411 mod->name, name, s->module->name,
412 s->module->is_vmlinux ? "" : ".ko");
421 static void sym_set_crc(const char *name, unsigned int crc)
423 struct symbol *s = find_symbol(name);
426 * Ignore stand-alone __crc_*, which might be auto-generated symbols
427 * such as __*_veneer in ARM ELF.
436 static void *grab_file(const char *filename, size_t *size)
439 void *map = MAP_FAILED;
442 fd = open(filename, O_RDONLY);
449 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
453 if (map == MAP_FAILED)
458 static void release_file(void *file, size_t size)
463 static int parse_elf(struct elf_info *info, const char *filename)
469 const char *secstrings;
470 unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
472 hdr = grab_file(filename, &info->size);
474 if (ignore_missing_files) {
475 fprintf(stderr, "%s: %s (ignored)\n", filename,
483 if (info->size < sizeof(*hdr)) {
484 /* file too small, assume this is an empty .o file */
487 /* Is this a valid ELF file? */
488 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
489 (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
490 (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
491 (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
492 /* Not an ELF file - silently ignore it */
495 /* Fix endianness in ELF header */
496 hdr->e_type = TO_NATIVE(hdr->e_type);
497 hdr->e_machine = TO_NATIVE(hdr->e_machine);
498 hdr->e_version = TO_NATIVE(hdr->e_version);
499 hdr->e_entry = TO_NATIVE(hdr->e_entry);
500 hdr->e_phoff = TO_NATIVE(hdr->e_phoff);
501 hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
502 hdr->e_flags = TO_NATIVE(hdr->e_flags);
503 hdr->e_ehsize = TO_NATIVE(hdr->e_ehsize);
504 hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
505 hdr->e_phnum = TO_NATIVE(hdr->e_phnum);
506 hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
507 hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
508 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
509 sechdrs = (void *)hdr + hdr->e_shoff;
510 info->sechdrs = sechdrs;
512 /* Check if file offset is correct */
513 if (hdr->e_shoff > info->size) {
514 fatal("section header offset=%lu in file '%s' is bigger than filesize=%zu\n",
515 (unsigned long)hdr->e_shoff, filename, info->size);
519 if (hdr->e_shnum == SHN_UNDEF) {
521 * There are more than 64k sections,
522 * read count from .sh_size.
524 info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
527 info->num_sections = hdr->e_shnum;
529 if (hdr->e_shstrndx == SHN_XINDEX) {
530 info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
533 info->secindex_strings = hdr->e_shstrndx;
536 /* Fix endianness in section headers */
537 for (i = 0; i < info->num_sections; i++) {
538 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
539 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
540 sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags);
541 sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr);
542 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
543 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
544 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
545 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info);
546 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
547 sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize);
549 /* Find symbol table. */
550 secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
551 for (i = 1; i < info->num_sections; i++) {
553 int nobits = sechdrs[i].sh_type == SHT_NOBITS;
555 if (!nobits && sechdrs[i].sh_offset > info->size) {
556 fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
557 "sizeof(*hrd)=%zu\n", filename,
558 (unsigned long)sechdrs[i].sh_offset,
562 secname = secstrings + sechdrs[i].sh_name;
563 if (strcmp(secname, ".modinfo") == 0) {
565 fatal("%s has NOBITS .modinfo\n", filename);
566 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
567 info->modinfo_len = sechdrs[i].sh_size;
568 } else if (strcmp(secname, "__ksymtab") == 0)
569 info->export_sec = i;
570 else if (strcmp(secname, "__ksymtab_gpl") == 0)
571 info->export_gpl_sec = i;
573 if (sechdrs[i].sh_type == SHT_SYMTAB) {
574 unsigned int sh_link_idx;
576 info->symtab_start = (void *)hdr +
577 sechdrs[i].sh_offset;
578 info->symtab_stop = (void *)hdr +
579 sechdrs[i].sh_offset + sechdrs[i].sh_size;
580 sh_link_idx = sechdrs[i].sh_link;
581 info->strtab = (void *)hdr +
582 sechdrs[sh_link_idx].sh_offset;
585 /* 32bit section no. table? ("more than 64k sections") */
586 if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
587 symtab_shndx_idx = i;
588 info->symtab_shndx_start = (void *)hdr +
589 sechdrs[i].sh_offset;
590 info->symtab_shndx_stop = (void *)hdr +
591 sechdrs[i].sh_offset + sechdrs[i].sh_size;
594 if (!info->symtab_start)
595 fatal("%s has no symtab?\n", filename);
597 /* Fix endianness in symbols */
598 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
599 sym->st_shndx = TO_NATIVE(sym->st_shndx);
600 sym->st_name = TO_NATIVE(sym->st_name);
601 sym->st_value = TO_NATIVE(sym->st_value);
602 sym->st_size = TO_NATIVE(sym->st_size);
605 if (symtab_shndx_idx != ~0U) {
607 if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
608 fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
609 filename, sechdrs[symtab_shndx_idx].sh_link,
612 for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
620 static void parse_elf_finish(struct elf_info *info)
622 release_file(info->hdr, info->size);
625 static int ignore_undef_symbol(struct elf_info *info, const char *symname)
627 /* ignore __this_module, it will be resolved shortly */
628 if (strcmp(symname, "__this_module") == 0)
630 /* ignore global offset table */
631 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
633 if (info->hdr->e_machine == EM_PPC)
634 /* Special register function linked on all modules during final link of .ko */
635 if (strstarts(symname, "_restgpr_") ||
636 strstarts(symname, "_savegpr_") ||
637 strstarts(symname, "_rest32gpr_") ||
638 strstarts(symname, "_save32gpr_") ||
639 strstarts(symname, "_restvr_") ||
640 strstarts(symname, "_savevr_"))
642 if (info->hdr->e_machine == EM_PPC64)
643 /* Special register function linked on all modules during final link of .ko */
644 if (strstarts(symname, "_restgpr0_") ||
645 strstarts(symname, "_savegpr0_") ||
646 strstarts(symname, "_restvr_") ||
647 strstarts(symname, "_savevr_") ||
648 strcmp(symname, ".TOC.") == 0)
650 /* Do not ignore this symbol */
654 static void handle_modversion(const struct module *mod,
655 const struct elf_info *info,
656 const Elf_Sym *sym, const char *symname)
660 if (sym->st_shndx == SHN_UNDEF) {
661 warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n",
662 symname, mod->name, mod->is_vmlinux ? "" : ".ko");
666 if (sym->st_shndx == SHN_ABS) {
671 /* symbol points to the CRC in the ELF object */
672 crcp = sym_get_data(info, sym);
673 crc = TO_NATIVE(*crcp);
675 sym_set_crc(symname, crc);
678 static void handle_symbol(struct module *mod, struct elf_info *info,
679 const Elf_Sym *sym, const char *symname)
684 if (strstarts(symname, "__ksymtab"))
685 export = export_from_secname(info, get_secindex(info, sym));
687 export = export_from_sec(info, get_secindex(info, sym));
689 switch (sym->st_shndx) {
691 if (strstarts(symname, "__gnu_lto_")) {
692 /* Should warn here, but modpost runs before the linker */
694 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
697 /* undefined symbol */
698 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
699 ELF_ST_BIND(sym->st_info) != STB_WEAK)
701 if (ignore_undef_symbol(info, symname))
703 if (info->hdr->e_machine == EM_SPARC ||
704 info->hdr->e_machine == EM_SPARCV9) {
705 /* Ignore register directives. */
706 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
708 if (symname[0] == '.') {
709 char *munged = NOFAIL(strdup(symname));
711 munged[1] = toupper(munged[1]);
716 mod->unres = alloc_symbol(symname,
717 ELF_ST_BIND(sym->st_info) == STB_WEAK,
721 /* All exported symbols */
722 if (strstarts(symname, "__ksymtab_")) {
723 name = symname + strlen("__ksymtab_");
724 sym_add_exported(name, mod, export);
726 if (strcmp(symname, "init_module") == 0)
728 if (strcmp(symname, "cleanup_module") == 0)
729 mod->has_cleanup = 1;
735 * Parse tag=value strings from .modinfo section
737 static char *next_string(char *string, unsigned long *secsize)
739 /* Skip non-zero chars */
742 if ((*secsize)-- <= 1)
746 /* Skip any zero padding. */
749 if ((*secsize)-- <= 1)
755 static char *get_next_modinfo(struct elf_info *info, const char *tag,
759 unsigned int taglen = strlen(tag);
760 char *modinfo = info->modinfo;
761 unsigned long size = info->modinfo_len;
764 size -= prev - modinfo;
765 modinfo = next_string(prev, &size);
768 for (p = modinfo; p; p = next_string(p, &size)) {
769 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
770 return p + taglen + 1;
775 static char *get_modinfo(struct elf_info *info, const char *tag)
778 return get_next_modinfo(info, tag, NULL);
782 * Test if string s ends in string sub
785 static int strrcmp(const char *s, const char *sub)
793 sublen = strlen(sub);
795 if ((slen == 0) || (sublen == 0))
801 return memcmp(s + slen - sublen, sub, sublen);
804 static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
807 return elf->strtab + sym->st_name;
812 /* The pattern is an array of simple patterns.
813 * "foo" will match an exact string equal to "foo"
814 * "*foo" will match a string that ends with "foo"
815 * "foo*" will match a string that begins with "foo"
816 * "*foo*" will match a string that contains "foo"
818 static int match(const char *sym, const char * const pat[])
823 const char *endp = p + strlen(p) - 1;
826 if (*p == '*' && *endp == '*') {
827 char *bare = NOFAIL(strndup(p + 1, strlen(p) - 2));
828 char *here = strstr(sym, bare);
835 else if (*p == '*') {
836 if (strrcmp(sym, p + 1) == 0)
840 else if (*endp == '*') {
841 if (strncmp(sym, p, strlen(p) - 1) == 0)
846 if (strcmp(p, sym) == 0)
854 /* sections that we do not want to do full section mismatch check on */
855 static const char *const section_white_list[] =
859 ".cranges", /* sh64 */
860 ".zdebug*", /* Compressed debug sections. */
861 ".GCC.command.line", /* record-gcc-switches */
862 ".mdebug*", /* alpha, score, mips etc. */
863 ".pdr", /* alpha, score, mips etc. */
868 ".xt.prop", /* xtensa */
869 ".xt.lit", /* xtensa */
870 ".arcextmap*", /* arc */
871 ".gnu.linkonce.arcext*", /* arc : modules */
872 ".cmem*", /* EZchip */
873 ".fmt_slot*", /* EZchip */
880 * This is used to find sections missing the SHF_ALLOC flag.
881 * The cause of this is often a section specified in assembler
882 * without "ax" / "aw".
884 static void check_section(const char *modname, struct elf_info *elf,
887 const char *sec = sech_name(elf, sechdr);
889 if (sechdr->sh_type == SHT_PROGBITS &&
890 !(sechdr->sh_flags & SHF_ALLOC) &&
891 !match(sec, section_white_list)) {
892 warn("%s (%s): unexpected non-allocatable section.\n"
893 "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
894 "Note that for example <linux/init.h> contains\n"
895 "section definitions for use in .S files.\n\n",
902 #define ALL_INIT_DATA_SECTIONS \
903 ".init.setup", ".init.rodata", ".meminit.rodata", \
904 ".init.data", ".meminit.data"
905 #define ALL_EXIT_DATA_SECTIONS \
906 ".exit.data", ".memexit.data"
908 #define ALL_INIT_TEXT_SECTIONS \
909 ".init.text", ".meminit.text"
910 #define ALL_EXIT_TEXT_SECTIONS \
911 ".exit.text", ".memexit.text"
913 #define ALL_PCI_INIT_SECTIONS \
914 ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
915 ".pci_fixup_enable", ".pci_fixup_resume", \
916 ".pci_fixup_resume_early", ".pci_fixup_suspend"
918 #define ALL_XXXINIT_SECTIONS MEM_INIT_SECTIONS
919 #define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS
921 #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
922 #define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
924 #define DATA_SECTIONS ".data", ".data.rel"
925 #define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \
926 ".kprobes.text", ".cpuidle.text", ".noinstr.text"
927 #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
928 ".fixup", ".entry.text", ".exception.text", ".text.*", \
931 #define INIT_SECTIONS ".init.*"
932 #define MEM_INIT_SECTIONS ".meminit.*"
934 #define EXIT_SECTIONS ".exit.*"
935 #define MEM_EXIT_SECTIONS ".memexit.*"
937 #define ALL_TEXT_SECTIONS ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \
938 TEXT_SECTIONS, OTHER_TEXT_SECTIONS
940 /* init data sections */
941 static const char *const init_data_sections[] =
942 { ALL_INIT_DATA_SECTIONS, NULL };
944 /* all init sections */
945 static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL };
947 /* All init and exit sections (code + data) */
948 static const char *const init_exit_sections[] =
949 {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
951 /* all text sections */
952 static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL };
955 static const char *const data_sections[] = { DATA_SECTIONS, NULL };
958 /* symbols in .data that may refer to init/exit sections */
959 #define DEFAULT_SYMBOL_WHITE_LIST \
961 "*_template", /* scsi uses *_template a lot */ \
962 "*_timer", /* arm uses ops structures named _timer a lot */ \
963 "*_sht", /* scsi also used *_sht to some extent */ \
969 static const char *const head_sections[] = { ".head.text*", NULL };
970 static const char *const linker_symbols[] =
971 { "__init_begin", "_sinittext", "_einittext", NULL };
972 static const char *const optim_symbols[] = { "*.constprop.*", NULL };
979 XXXINIT_TO_SOME_INIT,
980 XXXEXIT_TO_SOME_EXIT,
981 ANY_INIT_TO_ANY_EXIT,
982 ANY_EXIT_TO_ANY_INIT,
988 * Describe how to match sections on different criterias:
990 * @fromsec: Array of sections to be matched.
992 * @bad_tosec: Relocations applied to a section in @fromsec to a section in
993 * this array is forbidden (black-list). Can be empty.
995 * @good_tosec: Relocations applied to a section in @fromsec must be
996 * targetting sections in this array (white-list). Can be empty.
998 * @mismatch: Type of mismatch.
1000 * @symbol_white_list: Do not match a relocation to a symbol in this list
1001 * even if it is targetting a section in @bad_to_sec.
1003 * @handler: Specific handler to call when a match is found. If NULL,
1004 * default_mismatch_handler() will be called.
1007 struct sectioncheck {
1008 const char *fromsec[20];
1009 const char *bad_tosec[20];
1010 const char *good_tosec[20];
1011 enum mismatch mismatch;
1012 const char *symbol_white_list[20];
1013 void (*handler)(const char *modname, struct elf_info *elf,
1014 const struct sectioncheck* const mismatch,
1015 Elf_Rela *r, Elf_Sym *sym, const char *fromsec);
1019 static void extable_mismatch_handler(const char *modname, struct elf_info *elf,
1020 const struct sectioncheck* const mismatch,
1021 Elf_Rela *r, Elf_Sym *sym,
1022 const char *fromsec);
1024 static const struct sectioncheck sectioncheck[] = {
1025 /* Do not reference init/exit code/data from
1026 * normal code and data
1029 .fromsec = { TEXT_SECTIONS, NULL },
1030 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1031 .mismatch = TEXT_TO_ANY_INIT,
1032 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1035 .fromsec = { DATA_SECTIONS, NULL },
1036 .bad_tosec = { ALL_XXXINIT_SECTIONS, NULL },
1037 .mismatch = DATA_TO_ANY_INIT,
1038 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1041 .fromsec = { DATA_SECTIONS, NULL },
1042 .bad_tosec = { INIT_SECTIONS, NULL },
1043 .mismatch = DATA_TO_ANY_INIT,
1044 .symbol_white_list = {
1045 "*_template", "*_timer", "*_sht", "*_ops",
1046 "*_probe", "*_probe_one", "*_console", NULL
1050 .fromsec = { TEXT_SECTIONS, NULL },
1051 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1052 .mismatch = TEXT_TO_ANY_EXIT,
1053 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1056 .fromsec = { DATA_SECTIONS, NULL },
1057 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1058 .mismatch = DATA_TO_ANY_EXIT,
1059 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1061 /* Do not reference init code/data from meminit code/data */
1063 .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
1064 .bad_tosec = { INIT_SECTIONS, NULL },
1065 .mismatch = XXXINIT_TO_SOME_INIT,
1066 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1068 /* Do not reference exit code/data from memexit code/data */
1070 .fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
1071 .bad_tosec = { EXIT_SECTIONS, NULL },
1072 .mismatch = XXXEXIT_TO_SOME_EXIT,
1073 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1075 /* Do not use exit code/data from init code */
1077 .fromsec = { ALL_INIT_SECTIONS, NULL },
1078 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1079 .mismatch = ANY_INIT_TO_ANY_EXIT,
1080 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1082 /* Do not use init code/data from exit code */
1084 .fromsec = { ALL_EXIT_SECTIONS, NULL },
1085 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1086 .mismatch = ANY_EXIT_TO_ANY_INIT,
1087 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1090 .fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
1091 .bad_tosec = { INIT_SECTIONS, NULL },
1092 .mismatch = ANY_INIT_TO_ANY_EXIT,
1093 .symbol_white_list = { NULL },
1095 /* Do not export init/exit functions or data */
1097 .fromsec = { "__ksymtab*", NULL },
1098 .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
1099 .mismatch = EXPORT_TO_INIT_EXIT,
1100 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1103 .fromsec = { "__ex_table", NULL },
1104 /* If you're adding any new black-listed sections in here, consider
1105 * adding a special 'printer' for them in scripts/check_extable.
1107 .bad_tosec = { ".altinstr_replacement", NULL },
1108 .good_tosec = {ALL_TEXT_SECTIONS , NULL},
1109 .mismatch = EXTABLE_TO_NON_TEXT,
1110 .handler = extable_mismatch_handler,
1114 static const struct sectioncheck *section_mismatch(
1115 const char *fromsec, const char *tosec)
1118 int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
1119 const struct sectioncheck *check = §ioncheck[0];
1122 * The target section could be the SHT_NUL section when we're
1123 * handling relocations to un-resolved symbols, trying to match it
1124 * doesn't make much sense and causes build failures on parisc
1130 for (i = 0; i < elems; i++) {
1131 if (match(fromsec, check->fromsec)) {
1132 if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
1134 if (check->good_tosec[0] && !match(tosec, check->good_tosec))
1143 * Whitelist to allow certain references to pass with no warning.
1146 * If a module parameter is declared __initdata and permissions=0
1147 * then this is legal despite the warning generated.
1148 * We cannot see value of permissions here, so just ignore
1150 * The pattern is identified by:
1151 * tosec = .init.data
1156 * module_param_call() ops can refer to __init set function if permissions=0
1157 * The pattern is identified by:
1158 * tosec = .init.text
1160 * atsym = __param_ops_*
1163 * Many drivers utilise a *driver container with references to
1164 * add, remove, probe functions etc.
1165 * the pattern is identified by:
1166 * tosec = init or exit section
1167 * fromsec = data section
1168 * atsym = *driver, *_template, *_sht, *_ops, *_probe,
1169 * *probe_one, *_console, *_timer
1172 * Whitelist all references from .head.text to any init section
1175 * Some symbols belong to init section but still it is ok to reference
1176 * these from non-init sections as these symbols don't have any memory
1177 * allocated for them and symbol address and value are same. So even
1178 * if init section is freed, its ok to reference those symbols.
1179 * For ex. symbols marking the init section boundaries.
1180 * This pattern is identified by
1181 * refsymname = __init_begin, _sinittext, _einittext
1184 * GCC may optimize static inlines when fed constant arg(s) resulting
1185 * in functions like cpumask_empty() -- generating an associated symbol
1186 * cpumask_empty.constprop.3 that appears in the audit. If the const that
1187 * is passed in comes from __init, like say nmi_ipi_mask, we get a
1188 * meaningless section warning. May need to add isra symbols too...
1189 * This pattern is identified by
1190 * tosec = init section
1191 * fromsec = text section
1192 * refsymname = *.constprop.*
1195 * Hide section mismatch warnings for ELF local symbols. The goal
1196 * is to eliminate false positive modpost warnings caused by
1197 * compiler-generated ELF local symbol names such as ".LANCHOR1".
1198 * Autogenerated symbol names bypass modpost's "Pattern 2"
1199 * whitelisting, which relies on pattern-matching against symbol
1200 * names to work. (One situation where gcc can autogenerate ELF
1201 * local symbols is when "-fsection-anchors" is used.)
1203 static int secref_whitelist(const struct sectioncheck *mismatch,
1204 const char *fromsec, const char *fromsym,
1205 const char *tosec, const char *tosym)
1207 /* Check for pattern 1 */
1208 if (match(tosec, init_data_sections) &&
1209 match(fromsec, data_sections) &&
1210 strstarts(fromsym, "__param"))
1213 /* Check for pattern 1a */
1214 if (strcmp(tosec, ".init.text") == 0 &&
1215 match(fromsec, data_sections) &&
1216 strstarts(fromsym, "__param_ops_"))
1219 /* Check for pattern 2 */
1220 if (match(tosec, init_exit_sections) &&
1221 match(fromsec, data_sections) &&
1222 match(fromsym, mismatch->symbol_white_list))
1225 /* Check for pattern 3 */
1226 if (match(fromsec, head_sections) &&
1227 match(tosec, init_sections))
1230 /* Check for pattern 4 */
1231 if (match(tosym, linker_symbols))
1234 /* Check for pattern 5 */
1235 if (match(fromsec, text_sections) &&
1236 match(tosec, init_sections) &&
1237 match(fromsym, optim_symbols))
1240 /* Check for pattern 6 */
1241 if (strstarts(fromsym, ".L"))
1247 static inline int is_arm_mapping_symbol(const char *str)
1249 return str[0] == '$' && strchr("axtd", str[1])
1250 && (str[2] == '\0' || str[2] == '.');
1254 * If there's no name there, ignore it; likewise, ignore it if it's
1255 * one of the magic symbols emitted used by current ARM tools.
1257 * Otherwise if find_symbols_between() returns those symbols, they'll
1258 * fail the whitelist tests and cause lots of false alarms ... fixable
1259 * only by merging __exit and __init sections into __text, bloating
1260 * the kernel (which is especially evil on embedded platforms).
1262 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1264 const char *name = elf->strtab + sym->st_name;
1266 if (!name || !strlen(name))
1268 return !is_arm_mapping_symbol(name);
1272 * Find symbol based on relocation record info.
1273 * In some cases the symbol supplied is a valid symbol so
1274 * return refsym. If st_name != 0 we assume this is a valid symbol.
1275 * In other cases the symbol needs to be looked up in the symbol table
1276 * based on section and address.
1278 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
1282 Elf_Sym *near = NULL;
1283 Elf64_Sword distance = 20;
1285 unsigned int relsym_secindex;
1287 if (relsym->st_name != 0)
1290 relsym_secindex = get_secindex(elf, relsym);
1291 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1292 if (get_secindex(elf, sym) != relsym_secindex)
1294 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
1296 if (!is_valid_name(elf, sym))
1298 if (sym->st_value == addr)
1300 /* Find a symbol nearby - addr are maybe negative */
1301 d = sym->st_value - addr;
1303 d = addr - sym->st_value;
1309 /* We need a close match */
1317 * Find symbols before or equal addr and after addr - in the section sec.
1318 * If we find two symbols with equal offset prefer one with a valid name.
1319 * The ELF format may have a better way to detect what type of symbol
1320 * it is, but this works for now.
1322 static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1326 Elf_Sym *near = NULL;
1327 Elf_Addr distance = ~0;
1329 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1332 if (is_shndx_special(sym->st_shndx))
1334 symsec = sec_name(elf, get_secindex(elf, sym));
1335 if (strcmp(symsec, sec) != 0)
1337 if (!is_valid_name(elf, sym))
1339 if (sym->st_value <= addr) {
1340 if ((addr - sym->st_value) < distance) {
1341 distance = addr - sym->st_value;
1343 } else if ((addr - sym->st_value) == distance) {
1352 * Convert a section name to the function/data attribute
1353 * .init.text => __init
1354 * .memexitconst => __memconst
1357 * The memory of returned value has been allocated on a heap. The user of this
1358 * method should free it after usage.
1360 static char *sec2annotation(const char *s)
1362 if (match(s, init_exit_sections)) {
1363 char *p = NOFAIL(malloc(20));
1370 while (*s && *s != '.')
1375 if (strstr(s, "rodata") != NULL)
1376 strcat(p, "const ");
1377 else if (strstr(s, "data") != NULL)
1383 return NOFAIL(strdup(""));
1387 static int is_function(Elf_Sym *sym)
1390 return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1395 static void print_section_list(const char * const list[20])
1397 const char *const *s = list;
1400 fprintf(stderr, "%s", *s);
1403 fprintf(stderr, ", ");
1405 fprintf(stderr, "\n");
1408 static inline void get_pretty_name(int is_func, const char** name, const char** name_p)
1411 case 0: *name = "variable"; *name_p = ""; break;
1412 case 1: *name = "function"; *name_p = "()"; break;
1413 default: *name = "(unknown reference)"; *name_p = ""; break;
1418 * Print a warning about a section mismatch.
1419 * Try to find symbols near it so user can find it.
1420 * Check whitelist before warning - it may be a false positive.
1422 static void report_sec_mismatch(const char *modname,
1423 const struct sectioncheck *mismatch,
1424 const char *fromsec,
1425 unsigned long long fromaddr,
1426 const char *fromsym,
1428 const char *tosec, const char *tosym,
1431 const char *from, *from_p;
1432 const char *to, *to_p;
1436 sec_mismatch_count++;
1438 get_pretty_name(from_is_func, &from, &from_p);
1439 get_pretty_name(to_is_func, &to, &to_p);
1441 warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1442 "to the %s %s:%s%s\n",
1443 modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1446 switch (mismatch->mismatch) {
1447 case TEXT_TO_ANY_INIT:
1448 prl_from = sec2annotation(fromsec);
1449 prl_to = sec2annotation(tosec);
1451 "The function %s%s() references\n"
1453 "This is often because %s lacks a %s\n"
1454 "annotation or the annotation of %s is wrong.\n",
1456 to, prl_to, tosym, to_p,
1457 fromsym, prl_to, tosym);
1461 case DATA_TO_ANY_INIT: {
1462 prl_to = sec2annotation(tosec);
1464 "The variable %s references\n"
1466 "If the reference is valid then annotate the\n"
1467 "variable with __init* or __refdata (see linux/init.h) "
1468 "or name the variable:\n",
1469 fromsym, to, prl_to, tosym, to_p);
1470 print_section_list(mismatch->symbol_white_list);
1474 case TEXT_TO_ANY_EXIT:
1475 prl_to = sec2annotation(tosec);
1477 "The function %s() references a %s in an exit section.\n"
1478 "Often the %s %s%s has valid usage outside the exit section\n"
1479 "and the fix is to remove the %sannotation of %s.\n",
1480 fromsym, to, to, tosym, to_p, prl_to, tosym);
1483 case DATA_TO_ANY_EXIT: {
1484 prl_to = sec2annotation(tosec);
1486 "The variable %s references\n"
1488 "If the reference is valid then annotate the\n"
1489 "variable with __exit* (see linux/init.h) or "
1490 "name the variable:\n",
1491 fromsym, to, prl_to, tosym, to_p);
1492 print_section_list(mismatch->symbol_white_list);
1496 case XXXINIT_TO_SOME_INIT:
1497 case XXXEXIT_TO_SOME_EXIT:
1498 prl_from = sec2annotation(fromsec);
1499 prl_to = sec2annotation(tosec);
1501 "The %s %s%s%s references\n"
1503 "If %s is only used by %s then\n"
1504 "annotate %s with a matching annotation.\n",
1505 from, prl_from, fromsym, from_p,
1506 to, prl_to, tosym, to_p,
1507 tosym, fromsym, tosym);
1511 case ANY_INIT_TO_ANY_EXIT:
1512 prl_from = sec2annotation(fromsec);
1513 prl_to = sec2annotation(tosec);
1515 "The %s %s%s%s references\n"
1517 "This is often seen when error handling "
1518 "in the init function\n"
1519 "uses functionality in the exit path.\n"
1520 "The fix is often to remove the %sannotation of\n"
1521 "%s%s so it may be used outside an exit section.\n",
1522 from, prl_from, fromsym, from_p,
1523 to, prl_to, tosym, to_p,
1524 prl_to, tosym, to_p);
1528 case ANY_EXIT_TO_ANY_INIT:
1529 prl_from = sec2annotation(fromsec);
1530 prl_to = sec2annotation(tosec);
1532 "The %s %s%s%s references\n"
1534 "This is often seen when error handling "
1535 "in the exit function\n"
1536 "uses functionality in the init path.\n"
1537 "The fix is often to remove the %sannotation of\n"
1538 "%s%s so it may be used outside an init section.\n",
1539 from, prl_from, fromsym, from_p,
1540 to, prl_to, tosym, to_p,
1541 prl_to, tosym, to_p);
1545 case EXPORT_TO_INIT_EXIT:
1546 prl_to = sec2annotation(tosec);
1548 "The symbol %s is exported and annotated %s\n"
1549 "Fix this by removing the %sannotation of %s "
1550 "or drop the export.\n",
1551 tosym, prl_to, prl_to, tosym);
1554 case EXTABLE_TO_NON_TEXT:
1555 fatal("There's a special handler for this mismatch type, "
1556 "we should never get here.");
1559 fprintf(stderr, "\n");
1562 static void default_mismatch_handler(const char *modname, struct elf_info *elf,
1563 const struct sectioncheck* const mismatch,
1564 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1570 const char *fromsym;
1572 from = find_elf_symbol2(elf, r->r_offset, fromsec);
1573 fromsym = sym_name(elf, from);
1575 if (strstarts(fromsym, "reference___initcall"))
1578 tosec = sec_name(elf, get_secindex(elf, sym));
1579 to = find_elf_symbol(elf, r->r_addend, sym);
1580 tosym = sym_name(elf, to);
1582 /* check whitelist - we may ignore it */
1583 if (secref_whitelist(mismatch,
1584 fromsec, fromsym, tosec, tosym)) {
1585 report_sec_mismatch(modname, mismatch,
1586 fromsec, r->r_offset, fromsym,
1587 is_function(from), tosec, tosym,
1592 static int is_executable_section(struct elf_info* elf, unsigned int section_index)
1594 if (section_index > elf->num_sections)
1595 fatal("section_index is outside elf->num_sections!\n");
1597 return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR);
1601 * We rely on a gross hack in section_rel[a]() calling find_extable_entry_size()
1602 * to know the sizeof(struct exception_table_entry) for the target architecture.
1604 static unsigned int extable_entry_size = 0;
1605 static void find_extable_entry_size(const char* const sec, const Elf_Rela* r)
1608 * If we're currently checking the second relocation within __ex_table,
1609 * that relocation offset tells us the offsetof(struct
1610 * exception_table_entry, fixup) which is equal to sizeof(struct
1611 * exception_table_entry) divided by two. We use that to our advantage
1612 * since there's no portable way to get that size as every architecture
1613 * seems to go with different sized types. Not pretty but better than
1614 * hard-coding the size for every architecture..
1616 if (!extable_entry_size)
1617 extable_entry_size = r->r_offset * 2;
1620 static inline bool is_extable_fault_address(Elf_Rela *r)
1623 * extable_entry_size is only discovered after we've handled the
1624 * _second_ relocation in __ex_table, so only abort when we're not
1625 * handling the first reloc and extable_entry_size is zero.
1627 if (r->r_offset && extable_entry_size == 0)
1628 fatal("extable_entry size hasn't been discovered!\n");
1630 return ((r->r_offset == 0) ||
1631 (r->r_offset % extable_entry_size == 0));
1634 #define is_second_extable_reloc(Start, Cur, Sec) \
1635 (((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0))
1637 static void report_extable_warnings(const char* modname, struct elf_info* elf,
1638 const struct sectioncheck* const mismatch,
1639 Elf_Rela* r, Elf_Sym* sym,
1640 const char* fromsec, const char* tosec)
1642 Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec);
1643 const char* fromsym_name = sym_name(elf, fromsym);
1644 Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym);
1645 const char* tosym_name = sym_name(elf, tosym);
1646 const char* from_pretty_name;
1647 const char* from_pretty_name_p;
1648 const char* to_pretty_name;
1649 const char* to_pretty_name_p;
1651 get_pretty_name(is_function(fromsym),
1652 &from_pretty_name, &from_pretty_name_p);
1653 get_pretty_name(is_function(tosym),
1654 &to_pretty_name, &to_pretty_name_p);
1656 warn("%s(%s+0x%lx): Section mismatch in reference"
1657 " from the %s %s%s to the %s %s:%s%s\n",
1658 modname, fromsec, (long)r->r_offset, from_pretty_name,
1659 fromsym_name, from_pretty_name_p,
1660 to_pretty_name, tosec, tosym_name, to_pretty_name_p);
1662 if (!match(tosec, mismatch->bad_tosec) &&
1663 is_executable_section(elf, get_secindex(elf, sym)))
1665 "The relocation at %s+0x%lx references\n"
1666 "section \"%s\" which is not in the list of\n"
1667 "authorized sections. If you're adding a new section\n"
1668 "and/or if this reference is valid, add \"%s\" to the\n"
1669 "list of authorized sections to jump to on fault.\n"
1670 "This can be achieved by adding \"%s\" to \n"
1671 "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
1672 fromsec, (long)r->r_offset, tosec, tosec, tosec);
1675 static void extable_mismatch_handler(const char* modname, struct elf_info *elf,
1676 const struct sectioncheck* const mismatch,
1677 Elf_Rela* r, Elf_Sym* sym,
1678 const char *fromsec)
1680 const char* tosec = sec_name(elf, get_secindex(elf, sym));
1682 sec_mismatch_count++;
1684 report_extable_warnings(modname, elf, mismatch, r, sym, fromsec, tosec);
1686 if (match(tosec, mismatch->bad_tosec))
1687 fatal("The relocation at %s+0x%lx references\n"
1688 "section \"%s\" which is black-listed.\n"
1689 "Something is seriously wrong and should be fixed.\n"
1690 "You might get more information about where this is\n"
1691 "coming from by using scripts/check_extable.sh %s\n",
1692 fromsec, (long)r->r_offset, tosec, modname);
1693 else if (!is_executable_section(elf, get_secindex(elf, sym))) {
1694 if (is_extable_fault_address(r))
1695 fatal("The relocation at %s+0x%lx references\n"
1696 "section \"%s\" which is not executable, IOW\n"
1697 "it is not possible for the kernel to fault\n"
1698 "at that address. Something is seriously wrong\n"
1699 "and should be fixed.\n",
1700 fromsec, (long)r->r_offset, tosec);
1702 fatal("The relocation at %s+0x%lx references\n"
1703 "section \"%s\" which is not executable, IOW\n"
1704 "the kernel will fault if it ever tries to\n"
1705 "jump to it. Something is seriously wrong\n"
1706 "and should be fixed.\n",
1707 fromsec, (long)r->r_offset, tosec);
1711 static void check_section_mismatch(const char *modname, struct elf_info *elf,
1712 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1714 const char *tosec = sec_name(elf, get_secindex(elf, sym));
1715 const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec);
1718 if (mismatch->handler)
1719 mismatch->handler(modname, elf, mismatch,
1722 default_mismatch_handler(modname, elf, mismatch,
1727 static unsigned int *reloc_location(struct elf_info *elf,
1728 Elf_Shdr *sechdr, Elf_Rela *r)
1730 return sym_get_data_by_offset(elf, sechdr->sh_info, r->r_offset);
1733 static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1735 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1736 unsigned int *location = reloc_location(elf, sechdr, r);
1740 r->r_addend = TO_NATIVE(*location);
1743 r->r_addend = TO_NATIVE(*location) + 4;
1744 /* For CONFIG_RELOCATABLE=y */
1745 if (elf->hdr->e_type == ET_EXEC)
1746 r->r_addend += r->r_offset;
1753 #define R_ARM_CALL 28
1755 #ifndef R_ARM_JUMP24
1756 #define R_ARM_JUMP24 29
1759 #ifndef R_ARM_THM_CALL
1760 #define R_ARM_THM_CALL 10
1762 #ifndef R_ARM_THM_JUMP24
1763 #define R_ARM_THM_JUMP24 30
1765 #ifndef R_ARM_THM_JUMP19
1766 #define R_ARM_THM_JUMP19 51
1769 static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1771 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1775 /* From ARM ABI: (S + A) | T */
1776 r->r_addend = (int)(long)
1777 (elf->symtab_start + ELF_R_SYM(r->r_info));
1782 case R_ARM_THM_CALL:
1783 case R_ARM_THM_JUMP24:
1784 case R_ARM_THM_JUMP19:
1785 /* From ARM ABI: ((S + A) | T) - P */
1786 r->r_addend = (int)(long)(elf->hdr +
1788 (r->r_offset - sechdr->sh_addr));
1796 static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1798 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1799 unsigned int *location = reloc_location(elf, sechdr, r);
1802 if (r_typ == R_MIPS_HI16)
1803 return 1; /* skip this */
1804 inst = TO_NATIVE(*location);
1807 r->r_addend = inst & 0xffff;
1810 r->r_addend = (inst & 0x03ffffff) << 2;
1819 static void section_rela(const char *modname, struct elf_info *elf,
1826 const char *fromsec;
1828 Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1829 Elf_Rela *stop = (void *)start + sechdr->sh_size;
1831 fromsec = sech_name(elf, sechdr);
1832 fromsec += strlen(".rela");
1833 /* if from section (name) is know good then skip it */
1834 if (match(fromsec, section_white_list))
1837 for (rela = start; rela < stop; rela++) {
1838 r.r_offset = TO_NATIVE(rela->r_offset);
1839 #if KERNEL_ELFCLASS == ELFCLASS64
1840 if (elf->hdr->e_machine == EM_MIPS) {
1842 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1843 r_sym = TO_NATIVE(r_sym);
1844 r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1845 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1847 r.r_info = TO_NATIVE(rela->r_info);
1848 r_sym = ELF_R_SYM(r.r_info);
1851 r.r_info = TO_NATIVE(rela->r_info);
1852 r_sym = ELF_R_SYM(r.r_info);
1854 r.r_addend = TO_NATIVE(rela->r_addend);
1855 sym = elf->symtab_start + r_sym;
1856 /* Skip special sections */
1857 if (is_shndx_special(sym->st_shndx))
1859 if (is_second_extable_reloc(start, rela, fromsec))
1860 find_extable_entry_size(fromsec, &r);
1861 check_section_mismatch(modname, elf, &r, sym, fromsec);
1865 static void section_rel(const char *modname, struct elf_info *elf,
1872 const char *fromsec;
1874 Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1875 Elf_Rel *stop = (void *)start + sechdr->sh_size;
1877 fromsec = sech_name(elf, sechdr);
1878 fromsec += strlen(".rel");
1879 /* if from section (name) is know good then skip it */
1880 if (match(fromsec, section_white_list))
1883 for (rel = start; rel < stop; rel++) {
1884 r.r_offset = TO_NATIVE(rel->r_offset);
1885 #if KERNEL_ELFCLASS == ELFCLASS64
1886 if (elf->hdr->e_machine == EM_MIPS) {
1888 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1889 r_sym = TO_NATIVE(r_sym);
1890 r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1891 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1893 r.r_info = TO_NATIVE(rel->r_info);
1894 r_sym = ELF_R_SYM(r.r_info);
1897 r.r_info = TO_NATIVE(rel->r_info);
1898 r_sym = ELF_R_SYM(r.r_info);
1901 switch (elf->hdr->e_machine) {
1903 if (addend_386_rel(elf, sechdr, &r))
1907 if (addend_arm_rel(elf, sechdr, &r))
1911 if (addend_mips_rel(elf, sechdr, &r))
1915 sym = elf->symtab_start + r_sym;
1916 /* Skip special sections */
1917 if (is_shndx_special(sym->st_shndx))
1919 if (is_second_extable_reloc(start, rel, fromsec))
1920 find_extable_entry_size(fromsec, &r);
1921 check_section_mismatch(modname, elf, &r, sym, fromsec);
1926 * A module includes a number of sections that are discarded
1927 * either when loaded or when used as built-in.
1928 * For loaded modules all functions marked __init and all data
1929 * marked __initdata will be discarded when the module has been initialized.
1930 * Likewise for modules used built-in the sections marked __exit
1931 * are discarded because __exit marked function are supposed to be called
1932 * only when a module is unloaded which never happens for built-in modules.
1933 * The check_sec_ref() function traverses all relocation records
1934 * to find all references to a section that reference a section that will
1935 * be discarded and warns about it.
1937 static void check_sec_ref(struct module *mod, const char *modname,
1938 struct elf_info *elf)
1941 Elf_Shdr *sechdrs = elf->sechdrs;
1943 /* Walk through all sections */
1944 for (i = 0; i < elf->num_sections; i++) {
1945 check_section(modname, elf, &elf->sechdrs[i]);
1946 /* We want to process only relocation sections and not .init */
1947 if (sechdrs[i].sh_type == SHT_RELA)
1948 section_rela(modname, elf, &elf->sechdrs[i]);
1949 else if (sechdrs[i].sh_type == SHT_REL)
1950 section_rel(modname, elf, &elf->sechdrs[i]);
1954 static char *remove_dot(char *s)
1956 size_t n = strcspn(s, ".");
1959 size_t m = strspn(s + n + 1, "0123456789");
1960 if (m && (s[n + m] == '.' || s[n + m] == 0))
1963 /* strip trailing .lto */
1964 if (strends(s, ".lto"))
1965 s[strlen(s) - 4] = '\0';
1970 static void read_symbols(const char *modname)
1972 const char *symname;
1977 struct elf_info info = { };
1980 if (!parse_elf(&info, modname))
1986 /* strip trailing .o */
1987 tmp = NOFAIL(strdup(modname));
1988 tmp[strlen(tmp) - 2] = '\0';
1989 /* strip trailing .lto */
1990 if (strends(tmp, ".lto"))
1991 tmp[strlen(tmp) - 4] = '\0';
1992 mod = new_module(tmp);
1996 if (!mod->is_vmlinux) {
1997 license = get_modinfo(&info, "license");
1999 error("missing MODULE_LICENSE() in %s\n", modname);
2001 if (license_is_gpl_compatible(license))
2002 mod->gpl_compatible = 1;
2004 mod->gpl_compatible = 0;
2007 license = get_next_modinfo(&info, "license", license);
2010 namespace = get_modinfo(&info, "import_ns");
2012 add_namespace(&mod->imported_namespaces, namespace);
2013 namespace = get_next_modinfo(&info, "import_ns",
2018 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
2019 symname = remove_dot(info.strtab + sym->st_name);
2021 handle_symbol(mod, &info, sym, symname);
2022 handle_moddevtable(mod, &info, sym, symname);
2025 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
2026 symname = remove_dot(info.strtab + sym->st_name);
2028 /* Apply symbol namespaces from __kstrtabns_<symbol> entries. */
2029 if (strstarts(symname, "__kstrtabns_"))
2030 sym_update_namespace(symname + strlen("__kstrtabns_"),
2031 namespace_from_kstrtabns(&info,
2034 if (strstarts(symname, "__crc_"))
2035 handle_modversion(mod, &info, sym,
2036 symname + strlen("__crc_"));
2039 // check for static EXPORT_SYMBOL_* functions && global vars
2040 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
2041 unsigned char bind = ELF_ST_BIND(sym->st_info);
2043 if (bind == STB_GLOBAL || bind == STB_WEAK) {
2045 find_symbol(remove_dot(info.strtab +
2053 check_sec_ref(mod, modname, &info);
2055 if (!mod->is_vmlinux) {
2056 version = get_modinfo(&info, "version");
2057 if (version || all_versions)
2058 get_src_version(modname, mod->srcversion,
2059 sizeof(mod->srcversion) - 1);
2062 parse_elf_finish(&info);
2064 /* Our trick to get versioning for module struct etc. - it's
2065 * never passed as an argument to an exported function, so
2066 * the automatic versioning doesn't pick it up, but it's really
2067 * important anyhow */
2069 mod->unres = alloc_symbol("module_layout", 0, mod->unres);
2072 static void read_symbols_from_files(const char *filename)
2075 char fname[PATH_MAX];
2077 if (strcmp(filename, "-") != 0) {
2078 in = fopen(filename, "r");
2080 fatal("Can't open filenames file %s: %m", filename);
2083 while (fgets(fname, PATH_MAX, in) != NULL) {
2084 if (strends(fname, "\n"))
2085 fname[strlen(fname)-1] = '\0';
2086 read_symbols(fname);
2095 /* We first write the generated file into memory using the
2096 * following helper, then compare to the file on disk and
2097 * only update the later if anything changed */
2099 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
2100 const char *fmt, ...)
2107 len = vsnprintf(tmp, SZ, fmt, ap);
2108 buf_write(buf, tmp, len);
2112 void buf_write(struct buffer *buf, const char *s, int len)
2114 if (buf->size - buf->pos < len) {
2115 buf->size += len + SZ;
2116 buf->p = NOFAIL(realloc(buf->p, buf->size));
2118 strncpy(buf->p + buf->pos, s, len);
2122 static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
2126 error("GPL-incompatible module %s.ko uses GPL-only symbol '%s'\n",
2130 case export_unknown:
2136 static void check_exports(struct module *mod)
2138 struct symbol *s, *exp;
2140 for (s = mod->unres; s; s = s->next) {
2141 const char *basename;
2142 exp = find_symbol(s->name);
2143 if (!exp || exp->module == mod) {
2144 if (have_vmlinux && !s->weak)
2145 modpost_log(warn_unresolved ? LOG_WARN : LOG_ERROR,
2146 "\"%s\" [%s.ko] undefined!\n",
2147 s->name, mod->name);
2150 basename = strrchr(mod->name, '/');
2154 basename = mod->name;
2156 if (exp->namespace &&
2157 !module_imports_namespace(mod, exp->namespace)) {
2158 modpost_log(allow_missing_ns_imports ? LOG_WARN : LOG_ERROR,
2159 "module %s uses symbol %s from namespace %s, but does not import it.\n",
2160 basename, exp->name, exp->namespace);
2161 add_namespace(&mod->missing_namespaces, exp->namespace);
2164 if (!mod->gpl_compatible)
2165 check_for_gpl_usage(exp->export, basename, exp->name);
2169 static void check_modname_len(struct module *mod)
2171 const char *mod_name;
2173 mod_name = strrchr(mod->name, '/');
2174 if (mod_name == NULL)
2175 mod_name = mod->name;
2178 if (strlen(mod_name) >= MODULE_NAME_LEN)
2179 error("module name is too long [%s.ko]\n", mod->name);
2183 * Header for the generated file
2185 static void add_header(struct buffer *b, struct module *mod)
2187 buf_printf(b, "#include <linux/module.h>\n");
2189 * Include build-salt.h after module.h in order to
2190 * inherit the definitions.
2192 buf_printf(b, "#define INCLUDE_VERMAGIC\n");
2193 buf_printf(b, "#include <linux/build-salt.h>\n");
2194 buf_printf(b, "#include <linux/vermagic.h>\n");
2195 buf_printf(b, "#include <linux/compiler.h>\n");
2196 buf_printf(b, "\n");
2197 buf_printf(b, "BUILD_SALT;\n");
2198 buf_printf(b, "\n");
2199 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
2200 buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n");
2201 buf_printf(b, "\n");
2202 buf_printf(b, "__visible struct module __this_module\n");
2203 buf_printf(b, "__section(\".gnu.linkonce.this_module\") = {\n");
2204 buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
2206 buf_printf(b, "\t.init = init_module,\n");
2207 if (mod->has_cleanup)
2208 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
2209 "\t.exit = cleanup_module,\n"
2211 buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
2212 buf_printf(b, "};\n");
2215 static void add_intree_flag(struct buffer *b, int is_intree)
2218 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
2221 /* Cannot check for assembler */
2222 static void add_retpoline(struct buffer *b)
2224 buf_printf(b, "\n#ifdef CONFIG_RETPOLINE\n");
2225 buf_printf(b, "MODULE_INFO(retpoline, \"Y\");\n");
2226 buf_printf(b, "#endif\n");
2229 static void add_staging_flag(struct buffer *b, const char *name)
2231 if (strstarts(name, "drivers/staging"))
2232 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
2236 * Record CRCs for unresolved symbols
2238 static void add_versions(struct buffer *b, struct module *mod)
2240 struct symbol *s, *exp;
2242 for (s = mod->unres; s; s = s->next) {
2243 exp = find_symbol(s->name);
2244 if (!exp || exp->module == mod)
2246 s->module = exp->module;
2247 s->crc_valid = exp->crc_valid;
2254 buf_printf(b, "\n");
2255 buf_printf(b, "static const struct modversion_info ____versions[]\n");
2256 buf_printf(b, "__used __section(\"__versions\") = {\n");
2258 for (s = mod->unres; s; s = s->next) {
2261 if (!s->crc_valid) {
2262 warn("\"%s\" [%s.ko] has no CRC!\n",
2263 s->name, mod->name);
2266 if (strlen(s->name) >= MODULE_NAME_LEN) {
2267 error("too long symbol \"%s\" [%s.ko]\n",
2268 s->name, mod->name);
2271 buf_printf(b, "\t{ %#8x, \"%s\" },\n",
2275 buf_printf(b, "};\n");
2278 static void add_depends(struct buffer *b, struct module *mod)
2283 /* Clear ->seen flag of modules that own symbols needed by this. */
2284 for (s = mod->unres; s; s = s->next)
2286 s->module->seen = s->module->is_vmlinux;
2288 buf_printf(b, "\n");
2289 buf_printf(b, "MODULE_INFO(depends, \"");
2290 for (s = mod->unres; s; s = s->next) {
2295 if (s->module->seen)
2298 s->module->seen = 1;
2299 p = strrchr(s->module->name, '/');
2303 p = s->module->name;
2304 buf_printf(b, "%s%s", first ? "" : ",", p);
2307 buf_printf(b, "\");\n");
2310 static void add_srcversion(struct buffer *b, struct module *mod)
2312 if (mod->srcversion[0]) {
2313 buf_printf(b, "\n");
2314 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
2319 static void write_buf(struct buffer *b, const char *fname)
2323 file = fopen(fname, "w");
2328 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
2332 if (fclose(file) != 0) {
2338 static void write_if_changed(struct buffer *b, const char *fname)
2344 file = fopen(fname, "r");
2348 if (fstat(fileno(file), &st) < 0)
2351 if (st.st_size != b->pos)
2354 tmp = NOFAIL(malloc(b->pos));
2355 if (fread(tmp, 1, b->pos, file) != b->pos)
2358 if (memcmp(tmp, b->p, b->pos) != 0)
2370 write_buf(b, fname);
2373 /* parse Module.symvers file. line format:
2374 * 0x12345678<tab>symbol<tab>module<tab>export<tab>namespace
2376 static void read_dump(const char *fname)
2378 char *buf, *pos, *line;
2380 buf = read_text_file(fname);
2382 /* No symbol versions, silently ignore */
2387 while ((line = get_line(&pos))) {
2388 char *symname, *namespace, *modname, *d, *export;
2393 if (!(symname = strchr(line, '\t')))
2396 if (!(modname = strchr(symname, '\t')))
2399 if (!(export = strchr(modname, '\t')))
2402 if (!(namespace = strchr(export, '\t')))
2404 *namespace++ = '\0';
2406 crc = strtoul(line, &d, 16);
2407 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2409 mod = find_module(modname);
2411 mod = new_module(modname);
2414 s = sym_add_exported(symname, mod, export_no(export));
2416 sym_set_crc(symname, crc);
2417 sym_update_namespace(symname, namespace);
2423 fatal("parse error in symbol dump file\n");
2426 /* For normal builds always dump all symbols.
2427 * For external modules only dump symbols
2428 * that are not read from kernel Module.symvers.
2430 static int dump_sym(struct symbol *sym)
2432 if (!external_module)
2434 if (sym->module->from_dump)
2439 static void write_dump(const char *fname)
2441 struct buffer buf = { };
2442 struct symbol *symbol;
2443 const char *namespace;
2446 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
2447 symbol = symbolhash[n];
2449 if (dump_sym(symbol)) {
2450 namespace = symbol->namespace;
2451 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\t%s\n",
2452 symbol->crc, symbol->name,
2453 symbol->module->name,
2454 export_str(symbol->export),
2455 namespace ? namespace : "");
2457 symbol = symbol->next;
2460 write_buf(&buf, fname);
2464 static void write_namespace_deps_files(const char *fname)
2467 struct namespace_list *ns;
2468 struct buffer ns_deps_buf = {};
2470 for (mod = modules; mod; mod = mod->next) {
2472 if (mod->from_dump || !mod->missing_namespaces)
2475 buf_printf(&ns_deps_buf, "%s.ko:", mod->name);
2477 for (ns = mod->missing_namespaces; ns; ns = ns->next)
2478 buf_printf(&ns_deps_buf, " %s", ns->namespace);
2480 buf_printf(&ns_deps_buf, "\n");
2483 write_if_changed(&ns_deps_buf, fname);
2484 free(ns_deps_buf.p);
2488 struct dump_list *next;
2492 int main(int argc, char **argv)
2495 struct buffer buf = { };
2496 char *missing_namespace_deps = NULL;
2497 char *dump_write = NULL, *files_source = NULL;
2500 struct dump_list *dump_read_start = NULL;
2501 struct dump_list **dump_read_iter = &dump_read_start;
2503 while ((opt = getopt(argc, argv, "ei:mnT:o:awENd:")) != -1) {
2506 external_module = 1;
2510 NOFAIL(calloc(1, sizeof(**dump_read_iter)));
2511 (*dump_read_iter)->file = optarg;
2512 dump_read_iter = &(*dump_read_iter)->next;
2518 ignore_missing_files = 1;
2521 dump_write = optarg;
2527 files_source = optarg;
2530 warn_unresolved = 1;
2533 sec_mismatch_warn_only = false;
2536 allow_missing_ns_imports = 1;
2539 missing_namespace_deps = optarg;
2546 while (dump_read_start) {
2547 struct dump_list *tmp;
2549 read_dump(dump_read_start->file);
2550 tmp = dump_read_start->next;
2551 free(dump_read_start);
2552 dump_read_start = tmp;
2555 while (optind < argc)
2556 read_symbols(argv[optind++]);
2559 read_symbols_from_files(files_source);
2562 * When there's no vmlinux, don't print warnings about
2563 * unresolved symbols (since there'll be too many ;)
2566 warn("Symbol info of vmlinux is missing. Unresolved symbol check will be entirely skipped.\n");
2568 for (mod = modules; mod; mod = mod->next) {
2569 char fname[PATH_MAX];
2571 if (mod->is_vmlinux || mod->from_dump)
2576 check_modname_len(mod);
2579 add_header(&buf, mod);
2580 add_intree_flag(&buf, !external_module);
2581 add_retpoline(&buf);
2582 add_staging_flag(&buf, mod->name);
2583 add_versions(&buf, mod);
2584 add_depends(&buf, mod);
2585 add_moddevtable(&buf, mod);
2586 add_srcversion(&buf, mod);
2588 sprintf(fname, "%s.mod.c", mod->name);
2589 write_if_changed(&buf, fname);
2592 if (missing_namespace_deps)
2593 write_namespace_deps_files(missing_namespace_deps);
2596 write_dump(dump_write);
2597 if (sec_mismatch_count && !sec_mismatch_warn_only)
2598 error("Section mismatches detected.\n"
2599 "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");
2600 for (n = 0; n < SYMBOL_HASH_SIZE; n++) {
2603 for (s = symbolhash[n]; s; s = s->next) {
2605 error("\"%s\" [%s] is a static %s\n",
2606 s->name, s->module->name,
2607 export_str(s->export));
2613 return error_occurred ? 1 : 0;