1 /* Postprocess module symbol versions
3 * Copyright 2003 Kai Germaschewski
4 * Copyright 2002-2004 Rusty Russell, IBM Corporation
5 * Copyright 2006 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 ...
16 #include "../../include/linux/license.h"
18 /* Are we using CONFIG_MODVERSIONS? */
20 /* Warn about undefined symbols? (do so if we have vmlinux) */
22 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */
23 static int all_versions = 0;
24 /* If we are modposting external module set to 1 */
25 static int external_module = 0;
26 /* How a symbol is exported */
27 enum export {export_plain, export_gpl, export_gpl_future, export_unknown};
29 void fatal(const char *fmt, ...)
33 fprintf(stderr, "FATAL: ");
35 va_start(arglist, fmt);
36 vfprintf(stderr, fmt, arglist);
42 void warn(const char *fmt, ...)
46 fprintf(stderr, "WARNING: ");
48 va_start(arglist, fmt);
49 vfprintf(stderr, fmt, arglist);
53 static int is_vmlinux(const char *modname)
57 if ((myname = strrchr(modname, '/')))
62 return strcmp(myname, "vmlinux") == 0;
65 void *do_nofail(void *ptr, const char *expr)
68 fatal("modpost: Memory allocation failure: %s.\n", expr);
73 /* A list of all modules we processed */
75 static struct module *modules;
77 static struct module *find_module(char *modname)
81 for (mod = modules; mod; mod = mod->next)
82 if (strcmp(mod->name, modname) == 0)
87 static struct module *new_module(char *modname)
92 mod = NOFAIL(malloc(sizeof(*mod)));
93 memset(mod, 0, sizeof(*mod));
94 p = NOFAIL(strdup(modname));
96 /* strip trailing .o */
97 if ((s = strrchr(p, '.')) != NULL)
98 if (strcmp(s, ".o") == 0)
103 mod->gpl_compatible = -1;
110 /* A hash of all exported symbols,
111 * struct symbol is also used for lists of unresolved symbols */
113 #define SYMBOL_HASH_SIZE 1024
117 struct module *module;
121 unsigned int vmlinux:1; /* 1 if symbol is defined in vmlinux */
122 unsigned int kernel:1; /* 1 if symbol is from kernel
123 * (only for external modules) **/
124 unsigned int preloaded:1; /* 1 if symbol from Module.symvers */
125 enum export export; /* Type of export */
129 static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
131 /* This is based on the hash agorithm from gdbm, via tdb */
132 static inline unsigned int tdb_hash(const char *name)
134 unsigned value; /* Used to compute the hash value. */
135 unsigned i; /* Used to cycle through random values. */
137 /* Set the initial value from the key size. */
138 for (value = 0x238F13AF * strlen(name), i=0; name[i]; i++)
139 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
141 return (1103515243 * value + 12345);
145 * Allocate a new symbols for use in the hash of exported symbols or
146 * the list of unresolved symbols per module
148 static struct symbol *alloc_symbol(const char *name, unsigned int weak,
151 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
153 memset(s, 0, sizeof(*s));
154 strcpy(s->name, name);
160 /* For the hash of exported symbols */
161 static struct symbol *new_symbol(const char *name, struct module *module,
167 hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
168 new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
169 new->module = module;
170 new->export = export;
174 static struct symbol *find_symbol(const char *name)
178 /* For our purposes, .foo matches foo. PPC64 needs this. */
182 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s=s->next) {
183 if (strcmp(s->name, name) == 0)
193 { .str = "EXPORT_SYMBOL", .export = export_plain },
194 { .str = "EXPORT_SYMBOL_GPL", .export = export_gpl },
195 { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
196 { .str = "(unknown)", .export = export_unknown },
200 static const char *export_str(enum export ex)
202 return export_list[ex].str;
205 static enum export export_no(const char * s)
209 return export_unknown;
210 for (i = 0; export_list[i].export != export_unknown; i++) {
211 if (strcmp(export_list[i].str, s) == 0)
212 return export_list[i].export;
214 return export_unknown;
217 static enum export export_from_sec(struct elf_info *elf, Elf_Section sec)
219 if (sec == elf->export_sec)
221 else if (sec == elf->export_gpl_sec)
223 else if (sec == elf->export_gpl_future_sec)
224 return export_gpl_future;
226 return export_unknown;
230 * Add an exported symbol - it may have already been added without a
231 * CRC, in this case just update the CRC
233 static struct symbol *sym_add_exported(const char *name, struct module *mod,
236 struct symbol *s = find_symbol(name);
239 s = new_symbol(name, mod, export);
242 warn("%s: '%s' exported twice. Previous export "
243 "was in %s%s\n", mod->name, name,
245 is_vmlinux(s->module->name) ?"":".ko");
249 s->vmlinux = is_vmlinux(mod->name);
255 static void sym_update_crc(const char *name, struct module *mod,
256 unsigned int crc, enum export export)
258 struct symbol *s = find_symbol(name);
261 s = new_symbol(name, mod, export);
266 void *grab_file(const char *filename, unsigned long *size)
272 fd = open(filename, O_RDONLY);
273 if (fd < 0 || fstat(fd, &st) != 0)
277 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
280 if (map == MAP_FAILED)
286 * Return a copy of the next line in a mmap'ed file.
287 * spaces in the beginning of the line is trimmed away.
288 * Return a pointer to a static buffer.
290 char* get_next_line(unsigned long *pos, void *file, unsigned long size)
292 static char line[4096];
295 signed char *p = (signed char *)file + *pos;
298 for (; *pos < size ; (*pos)++)
300 if (skip && isspace(*p)) {
305 if (*p != '\n' && (*pos < size)) {
309 break; /* Too long, stop */
320 void release_file(void *file, unsigned long size)
325 static void parse_elf(struct elf_info *info, const char *filename)
328 Elf_Ehdr *hdr = info->hdr;
332 hdr = grab_file(filename, &info->size);
338 if (info->size < sizeof(*hdr))
341 /* Fix endianness in ELF header */
342 hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
343 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
344 hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
345 hdr->e_machine = TO_NATIVE(hdr->e_machine);
346 sechdrs = (void *)hdr + hdr->e_shoff;
347 info->sechdrs = sechdrs;
349 /* Fix endianness in section headers */
350 for (i = 0; i < hdr->e_shnum; i++) {
351 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
352 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
353 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
354 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
355 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
357 /* Find symbol table. */
358 for (i = 1; i < hdr->e_shnum; i++) {
359 const char *secstrings
360 = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
363 if (sechdrs[i].sh_offset > info->size)
365 secname = secstrings + sechdrs[i].sh_name;
366 if (strcmp(secname, ".modinfo") == 0) {
367 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
368 info->modinfo_len = sechdrs[i].sh_size;
369 } else if (strcmp(secname, "__ksymtab") == 0)
370 info->export_sec = i;
371 else if (strcmp(secname, "__ksymtab_gpl") == 0)
372 info->export_gpl_sec = i;
373 else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
374 info->export_gpl_future_sec = i;
376 if (sechdrs[i].sh_type != SHT_SYMTAB)
379 info->symtab_start = (void *)hdr + sechdrs[i].sh_offset;
380 info->symtab_stop = (void *)hdr + sechdrs[i].sh_offset
381 + sechdrs[i].sh_size;
382 info->strtab = (void *)hdr +
383 sechdrs[sechdrs[i].sh_link].sh_offset;
385 if (!info->symtab_start) {
386 fatal("%s has no symtab?\n", filename);
388 /* Fix endianness in symbols */
389 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
390 sym->st_shndx = TO_NATIVE(sym->st_shndx);
391 sym->st_name = TO_NATIVE(sym->st_name);
392 sym->st_value = TO_NATIVE(sym->st_value);
393 sym->st_size = TO_NATIVE(sym->st_size);
398 fatal("%s is truncated.\n", filename);
401 static void parse_elf_finish(struct elf_info *info)
403 release_file(info->hdr, info->size);
406 #define CRC_PFX MODULE_SYMBOL_PREFIX "__crc_"
407 #define KSYMTAB_PFX MODULE_SYMBOL_PREFIX "__ksymtab_"
409 static void handle_modversions(struct module *mod, struct elf_info *info,
410 Elf_Sym *sym, const char *symname)
413 enum export export = export_from_sec(info, sym->st_shndx);
415 switch (sym->st_shndx) {
417 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
421 if (memcmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
422 crc = (unsigned int) sym->st_value;
423 sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
428 /* undefined symbol */
429 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
430 ELF_ST_BIND(sym->st_info) != STB_WEAK)
432 /* ignore global offset table */
433 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
435 /* ignore __this_module, it will be resolved shortly */
436 if (strcmp(symname, MODULE_SYMBOL_PREFIX "__this_module") == 0)
438 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
439 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
440 /* add compatibility with older glibc */
441 #ifndef STT_SPARC_REGISTER
442 #define STT_SPARC_REGISTER STT_REGISTER
444 if (info->hdr->e_machine == EM_SPARC ||
445 info->hdr->e_machine == EM_SPARCV9) {
446 /* Ignore register directives. */
447 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
449 if (symname[0] == '.') {
450 char *munged = strdup(symname);
452 munged[1] = toupper(munged[1]);
458 if (memcmp(symname, MODULE_SYMBOL_PREFIX,
459 strlen(MODULE_SYMBOL_PREFIX)) == 0)
460 mod->unres = alloc_symbol(symname +
461 strlen(MODULE_SYMBOL_PREFIX),
462 ELF_ST_BIND(sym->st_info) == STB_WEAK,
466 /* All exported symbols */
467 if (memcmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
468 sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
471 if (strcmp(symname, MODULE_SYMBOL_PREFIX "init_module") == 0)
473 if (strcmp(symname, MODULE_SYMBOL_PREFIX "cleanup_module") == 0)
474 mod->has_cleanup = 1;
480 * Parse tag=value strings from .modinfo section
482 static char *next_string(char *string, unsigned long *secsize)
484 /* Skip non-zero chars */
487 if ((*secsize)-- <= 1)
491 /* Skip any zero padding. */
494 if ((*secsize)-- <= 1)
500 static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
501 const char *tag, char *info)
504 unsigned int taglen = strlen(tag);
505 unsigned long size = modinfo_len;
508 size -= info - (char *)modinfo;
509 modinfo = next_string(info, &size);
512 for (p = modinfo; p; p = next_string(p, &size)) {
513 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
514 return p + taglen + 1;
519 static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
523 return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
527 * Test if string s ends in string sub
530 static int strrcmp(const char *s, const char *sub)
538 sublen = strlen(sub);
540 if ((slen == 0) || (sublen == 0))
546 return memcmp(s + slen - sublen, sub, sublen);
550 * Whitelist to allow certain references to pass with no warning.
552 * If a module parameter is declared __initdata and permissions=0
553 * then this is legal despite the warning generated.
554 * We cannot see value of permissions here, so just ignore
556 * The pattern is identified by:
562 * Many drivers utilise a *driver container with references to
563 * add, remove, probe functions etc.
564 * These functions may often be marked __init and we do not want to
566 * the pattern is identified by:
567 * tosec = .init.text | .exit.text | .init.data
569 * atsym = *driver, *_template, *_sht, *_ops, *_probe, *probe_one
571 static int secref_whitelist(const char *tosec, const char *fromsec,
576 const char *pat2sym[] = {
578 "_template", /* scsi uses *_template a lot */
579 "_sht", /* scsi also used *_sht to some extent */
586 /* Check for pattern 1 */
587 if (strcmp(tosec, ".init.data") != 0)
589 if (strncmp(fromsec, ".data", strlen(".data")) != 0)
591 if (strncmp(atsym, "__param", strlen("__param")) != 0)
597 /* Check for pattern 2 */
598 if ((strcmp(tosec, ".init.text") != 0) &&
599 (strcmp(tosec, ".exit.text") != 0) &&
600 (strcmp(tosec, ".init.data") != 0))
602 if (strcmp(fromsec, ".data") != 0)
605 for (s = pat2sym; *s; s++)
606 if (strrcmp(atsym, *s) == 0)
613 * Find symbol based on relocation record info.
614 * In some cases the symbol supplied is a valid symbol so
615 * return refsym. If st_name != 0 we assume this is a valid symbol.
616 * In other cases the symbol needs to be looked up in the symbol table
617 * based on section and address.
619 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf_Addr addr,
624 if (relsym->st_name != 0)
626 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
627 if (sym->st_shndx != relsym->st_shndx)
629 if (sym->st_value == addr)
636 * Find symbols before or equal addr and after addr - in the section sec.
637 * If we find two symbols with equal offset prefer one with a valid name.
638 * The ELF format may have a better way to detect what type of symbol
639 * it is, but this works for now.
641 static void find_symbols_between(struct elf_info *elf, Elf_Addr addr,
643 Elf_Sym **before, Elf_Sym **after)
646 Elf_Ehdr *hdr = elf->hdr;
647 Elf_Addr beforediff = ~0;
648 Elf_Addr afterdiff = ~0;
649 const char *secstrings = (void *)hdr +
650 elf->sechdrs[hdr->e_shstrndx].sh_offset;
655 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
658 if (sym->st_shndx >= SHN_LORESERVE)
660 symsec = secstrings + elf->sechdrs[sym->st_shndx].sh_name;
661 if (strcmp(symsec, sec) != 0)
663 if (sym->st_value <= addr) {
664 if ((addr - sym->st_value) < beforediff) {
665 beforediff = addr - sym->st_value;
668 else if ((addr - sym->st_value) == beforediff) {
669 /* equal offset, valid name? */
670 const char *name = elf->strtab + sym->st_name;
671 if (name && strlen(name))
677 if ((sym->st_value - addr) < afterdiff) {
678 afterdiff = sym->st_value - addr;
681 else if ((sym->st_value - addr) == afterdiff) {
682 /* equal offset, valid name? */
683 const char *name = elf->strtab + sym->st_name;
684 if (name && strlen(name))
692 * Print a warning about a section mismatch.
693 * Try to find symbols near it so user can find it.
694 * Check whitelist before warning - it may be a false positive.
696 static void warn_sec_mismatch(const char *modname, const char *fromsec,
697 struct elf_info *elf, Elf_Sym *sym, Elf_Rela r)
699 const char *refsymname = "";
700 Elf_Sym *before, *after;
702 Elf_Ehdr *hdr = elf->hdr;
703 Elf_Shdr *sechdrs = elf->sechdrs;
704 const char *secstrings = (void *)hdr +
705 sechdrs[hdr->e_shstrndx].sh_offset;
706 const char *secname = secstrings + sechdrs[sym->st_shndx].sh_name;
708 find_symbols_between(elf, r.r_offset, fromsec, &before, &after);
710 refsym = find_elf_symbol(elf, r.r_addend, sym);
711 if (refsym && strlen(elf->strtab + refsym->st_name))
712 refsymname = elf->strtab + refsym->st_name;
714 /* check whitelist - we may ignore it */
716 secref_whitelist(secname, fromsec, elf->strtab + before->st_name))
719 if (before && after) {
720 warn("%s - Section mismatch: reference to %s:%s from %s "
721 "between '%s' (at offset 0x%llx) and '%s'\n",
722 modname, secname, refsymname, fromsec,
723 elf->strtab + before->st_name,
724 (long long)r.r_offset,
725 elf->strtab + after->st_name);
727 warn("%s - Section mismatch: reference to %s:%s from %s "
728 "after '%s' (at offset 0x%llx)\n",
729 modname, secname, refsymname, fromsec,
730 elf->strtab + before->st_name,
731 (long long)r.r_offset);
733 warn("%s - Section mismatch: reference to %s:%s from %s "
734 "before '%s' (at offset -0x%llx)\n",
735 modname, secname, refsymname, fromsec,
736 elf->strtab + after->st_name,
737 (long long)r.r_offset);
739 warn("%s - Section mismatch: reference to %s:%s from %s "
741 modname, secname, fromsec, refsymname,
742 (long long)r.r_offset);
747 * A module includes a number of sections that are discarded
748 * either when loaded or when used as built-in.
749 * For loaded modules all functions marked __init and all data
750 * marked __initdata will be discarded when the module has been intialized.
751 * Likewise for modules used built-in the sections marked __exit
752 * are discarded because __exit marked function are supposed to be called
753 * only when a moduel is unloaded which never happes for built-in modules.
754 * The check_sec_ref() function traverses all relocation records
755 * to find all references to a section that reference a section that will
756 * be discarded and warns about it.
758 static void check_sec_ref(struct module *mod, const char *modname,
759 struct elf_info *elf,
760 int section(const char*),
761 int section_ref_ok(const char *))
765 Elf_Ehdr *hdr = elf->hdr;
766 Elf_Shdr *sechdrs = elf->sechdrs;
767 const char *secstrings = (void *)hdr +
768 sechdrs[hdr->e_shstrndx].sh_offset;
770 /* Walk through all sections */
771 for (i = 0; i < hdr->e_shnum; i++) {
772 const char *name = secstrings + sechdrs[i].sh_name;
776 /* We want to process only relocation sections and not .init */
777 if (sechdrs[i].sh_type == SHT_RELA) {
779 Elf_Rela *start = (void *)hdr + sechdrs[i].sh_offset;
780 Elf_Rela *stop = (void*)start + sechdrs[i].sh_size;
781 name += strlen(".rela");
782 if (section_ref_ok(name))
785 for (rela = start; rela < stop; rela++) {
786 r.r_offset = TO_NATIVE(rela->r_offset);
787 #if KERNEL_ELFCLASS == ELFCLASS64
788 if (hdr->e_machine == EM_MIPS) {
789 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
790 r_sym = TO_NATIVE(r_sym);
792 r.r_info = TO_NATIVE(rela->r_info);
793 r_sym = ELF_R_SYM(r.r_info);
796 r.r_info = TO_NATIVE(rela->r_info);
797 r_sym = ELF_R_SYM(r.r_info);
799 r.r_addend = TO_NATIVE(rela->r_addend);
800 sym = elf->symtab_start + r_sym;
801 /* Skip special sections */
802 if (sym->st_shndx >= SHN_LORESERVE)
805 secname = secstrings +
806 sechdrs[sym->st_shndx].sh_name;
807 if (section(secname))
808 warn_sec_mismatch(modname, name,
811 } else if (sechdrs[i].sh_type == SHT_REL) {
813 Elf_Rel *start = (void *)hdr + sechdrs[i].sh_offset;
814 Elf_Rel *stop = (void*)start + sechdrs[i].sh_size;
815 name += strlen(".rel");
816 if (section_ref_ok(name))
819 for (rel = start; rel < stop; rel++) {
820 r.r_offset = TO_NATIVE(rel->r_offset);
821 #if KERNEL_ELFCLASS == ELFCLASS64
822 if (hdr->e_machine == EM_MIPS) {
823 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
824 r_sym = TO_NATIVE(r_sym);
826 r.r_info = TO_NATIVE(rel->r_info);
827 r_sym = ELF_R_SYM(r.r_info);
830 r.r_info = TO_NATIVE(rel->r_info);
831 r_sym = ELF_R_SYM(r.r_info);
834 sym = elf->symtab_start + r_sym;
835 /* Skip special sections */
836 if (sym->st_shndx >= SHN_LORESERVE)
839 secname = secstrings +
840 sechdrs[sym->st_shndx].sh_name;
841 if (section(secname))
842 warn_sec_mismatch(modname, name,
850 * Functions used only during module init is marked __init and is stored in
851 * a .init.text section. Likewise data is marked __initdata and stored in
852 * a .init.data section.
853 * If this section is one of these sections return 1
854 * See include/linux/init.h for the details
856 static int init_section(const char *name)
858 if (strcmp(name, ".init") == 0)
860 if (strncmp(name, ".init.", strlen(".init.")) == 0)
866 * Identify sections from which references to a .init section is OK.
868 * Unfortunately references to read only data that referenced .init
869 * sections had to be excluded. Almost all of these are false
870 * positives, they are created by gcc. The downside of excluding rodata
871 * is that there really are some user references from rodata to
872 * init code, e.g. drivers/video/vgacon.c:
874 * const struct consw vga_con = {
875 * con_startup: vgacon_startup,
877 * where vgacon_startup is __init. If you want to wade through the false
878 * positives, take out the check for rodata.
880 static int init_section_ref_ok(const char *name)
883 /* Absolute section names */
884 const char *namelist1[] = {
886 ".opd", /* see comment [OPD] at exit_section_ref_ok() */
887 ".toc1", /* used by ppc64 */
891 "__bug_table", /* used by powerpc for BUG() */
899 ".plt", /* seen on ARCH=um build on x86_64. Harmless */
902 /* Start of section names */
903 const char *namelist2[] = {
910 /* part of section name */
911 const char *namelist3 [] = {
912 ".unwind", /* sample: IA_64.unwind.init.text */
916 for (s = namelist1; *s; s++)
917 if (strcmp(*s, name) == 0)
919 for (s = namelist2; *s; s++)
920 if (strncmp(*s, name, strlen(*s)) == 0)
922 for (s = namelist3; *s; s++)
923 if (strstr(name, *s) != NULL)
925 if (strrcmp(name, ".init") == 0)
931 * Functions used only during module exit is marked __exit and is stored in
932 * a .exit.text section. Likewise data is marked __exitdata and stored in
933 * a .exit.data section.
934 * If this section is one of these sections return 1
935 * See include/linux/init.h for the details
937 static int exit_section(const char *name)
939 if (strcmp(name, ".exit.text") == 0)
941 if (strcmp(name, ".exit.data") == 0)
948 * Identify sections from which references to a .exit section is OK.
950 * [OPD] Keith Ownes <kaos@sgi.com> commented:
951 * For our future {in}sanity, add a comment that this is the ppc .opd
952 * section, not the ia64 .opd section.
953 * ia64 .opd should not point to discarded sections.
954 * [.rodata] like for .init.text we ignore .rodata references -same reason
956 static int exit_section_ref_ok(const char *name)
959 /* Absolute section names */
960 const char *namelist1[] = {
965 ".opd", /* See comment [OPD] */
966 ".toc1", /* used by ppc64 */
969 "__bug_table", /* used by powerpc for BUG() */
976 ".plt", /* seen on ARCH=um build on x86_64. Harmless */
979 /* Start of section names */
980 const char *namelist2[] = {
984 /* part of section name */
985 const char *namelist3 [] = {
986 ".unwind", /* Sample: IA_64.unwind.exit.text */
990 for (s = namelist1; *s; s++)
991 if (strcmp(*s, name) == 0)
993 for (s = namelist2; *s; s++)
994 if (strncmp(*s, name, strlen(*s)) == 0)
996 for (s = namelist3; *s; s++)
997 if (strstr(name, *s) != NULL)
1002 static void read_symbols(char *modname)
1004 const char *symname;
1008 struct elf_info info = { };
1011 parse_elf(&info, modname);
1013 mod = new_module(modname);
1015 /* When there's no vmlinux, don't print warnings about
1016 * unresolved symbols (since there'll be too many ;) */
1017 if (is_vmlinux(modname)) {
1022 license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1024 if (license_is_gpl_compatible(license))
1025 mod->gpl_compatible = 1;
1027 mod->gpl_compatible = 0;
1030 license = get_next_modinfo(info.modinfo, info.modinfo_len,
1031 "license", license);
1034 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1035 symname = info.strtab + sym->st_name;
1037 handle_modversions(mod, &info, sym, symname);
1038 handle_moddevtable(mod, &info, sym, symname);
1040 check_sec_ref(mod, modname, &info, init_section, init_section_ref_ok);
1041 check_sec_ref(mod, modname, &info, exit_section, exit_section_ref_ok);
1043 version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1045 maybe_frob_rcs_version(modname, version, info.modinfo,
1046 version - (char *)info.hdr);
1047 if (version || (all_versions && !is_vmlinux(modname)))
1048 get_src_version(modname, mod->srcversion,
1049 sizeof(mod->srcversion)-1);
1051 parse_elf_finish(&info);
1053 /* Our trick to get versioning for struct_module - it's
1054 * never passed as an argument to an exported function, so
1055 * the automatic versioning doesn't pick it up, but it's really
1056 * important anyhow */
1058 mod->unres = alloc_symbol("struct_module", 0, mod->unres);
1063 /* We first write the generated file into memory using the
1064 * following helper, then compare to the file on disk and
1065 * only update the later if anything changed */
1067 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
1068 const char *fmt, ...)
1075 len = vsnprintf(tmp, SZ, fmt, ap);
1076 buf_write(buf, tmp, len);
1080 void buf_write(struct buffer *buf, const char *s, int len)
1082 if (buf->size - buf->pos < len) {
1083 buf->size += len + SZ;
1084 buf->p = realloc(buf->p, buf->size);
1086 strncpy(buf->p + buf->pos, s, len);
1090 void check_license(struct module *mod)
1092 struct symbol *s, *exp;
1094 for (s = mod->unres; s; s = s->next) {
1095 const char *basename;
1096 if (mod->gpl_compatible == 1) {
1097 /* GPL-compatible modules may use all symbols */
1100 exp = find_symbol(s->name);
1101 if (!exp || exp->module == mod)
1103 basename = strrchr(mod->name, '/');
1106 switch (exp->export) {
1108 fatal("modpost: GPL-incompatible module %s "
1109 "uses GPL-only symbol '%s'\n",
1110 basename ? basename : mod->name,
1113 case export_gpl_future:
1114 warn("modpost: GPL-incompatible module %s "
1115 "uses future GPL-only symbol '%s'\n",
1116 basename ? basename : mod->name,
1119 case export_plain: /* ignore */ break;
1120 case export_unknown: /* ignore */ break;
1126 * Header for the generated file
1128 static void add_header(struct buffer *b, struct module *mod)
1130 buf_printf(b, "#include <linux/module.h>\n");
1131 buf_printf(b, "#include <linux/vermagic.h>\n");
1132 buf_printf(b, "#include <linux/compiler.h>\n");
1133 buf_printf(b, "\n");
1134 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
1135 buf_printf(b, "\n");
1136 buf_printf(b, "struct module __this_module\n");
1137 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
1138 buf_printf(b, " .name = KBUILD_MODNAME,\n");
1140 buf_printf(b, " .init = init_module,\n");
1141 if (mod->has_cleanup)
1142 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
1143 " .exit = cleanup_module,\n"
1145 buf_printf(b, "};\n");
1149 * Record CRCs for unresolved symbols
1151 static void add_versions(struct buffer *b, struct module *mod)
1153 struct symbol *s, *exp;
1155 for (s = mod->unres; s; s = s->next) {
1156 exp = find_symbol(s->name);
1157 if (!exp || exp->module == mod) {
1158 if (have_vmlinux && !s->weak)
1159 warn("\"%s\" [%s.ko] undefined!\n",
1160 s->name, mod->name);
1163 s->module = exp->module;
1164 s->crc_valid = exp->crc_valid;
1171 buf_printf(b, "\n");
1172 buf_printf(b, "static const struct modversion_info ____versions[]\n");
1173 buf_printf(b, "__attribute_used__\n");
1174 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
1176 for (s = mod->unres; s; s = s->next) {
1180 if (!s->crc_valid) {
1181 warn("\"%s\" [%s.ko] has no CRC!\n",
1182 s->name, mod->name);
1185 buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name);
1188 buf_printf(b, "};\n");
1191 static void add_depends(struct buffer *b, struct module *mod,
1192 struct module *modules)
1198 for (m = modules; m; m = m->next) {
1199 m->seen = is_vmlinux(m->name);
1202 buf_printf(b, "\n");
1203 buf_printf(b, "static const char __module_depends[]\n");
1204 buf_printf(b, "__attribute_used__\n");
1205 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
1206 buf_printf(b, "\"depends=");
1207 for (s = mod->unres; s; s = s->next) {
1211 if (s->module->seen)
1214 s->module->seen = 1;
1215 buf_printf(b, "%s%s", first ? "" : ",",
1216 strrchr(s->module->name, '/') + 1);
1219 buf_printf(b, "\";\n");
1222 static void add_srcversion(struct buffer *b, struct module *mod)
1224 if (mod->srcversion[0]) {
1225 buf_printf(b, "\n");
1226 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
1231 static void write_if_changed(struct buffer *b, const char *fname)
1237 file = fopen(fname, "r");
1241 if (fstat(fileno(file), &st) < 0)
1244 if (st.st_size != b->pos)
1247 tmp = NOFAIL(malloc(b->pos));
1248 if (fread(tmp, 1, b->pos, file) != b->pos)
1251 if (memcmp(tmp, b->p, b->pos) != 0)
1263 file = fopen(fname, "w");
1268 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
1275 /* parse Module.symvers file. line format:
1276 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
1278 static void read_dump(const char *fname, unsigned int kernel)
1280 unsigned long size, pos = 0;
1281 void *file = grab_file(fname, &size);
1285 /* No symbol versions, silently ignore */
1288 while ((line = get_next_line(&pos, file, size))) {
1289 char *symname, *modname, *d, *export, *end;
1294 if (!(symname = strchr(line, '\t')))
1297 if (!(modname = strchr(symname, '\t')))
1300 if ((export = strchr(modname, '\t')) != NULL)
1302 if (export && ((end = strchr(export, '\t')) != NULL))
1304 crc = strtoul(line, &d, 16);
1305 if (*symname == '\0' || *modname == '\0' || *d != '\0')
1308 if (!(mod = find_module(modname))) {
1309 if (is_vmlinux(modname)) {
1312 mod = new_module(NOFAIL(strdup(modname)));
1315 s = sym_add_exported(symname, mod, export_no(export));
1318 sym_update_crc(symname, mod, crc, export_no(export));
1322 fatal("parse error in symbol dump file\n");
1325 /* For normal builds always dump all symbols.
1326 * For external modules only dump symbols
1327 * that are not read from kernel Module.symvers.
1329 static int dump_sym(struct symbol *sym)
1331 if (!external_module)
1333 if (sym->vmlinux || sym->kernel)
1338 static void write_dump(const char *fname)
1340 struct buffer buf = { };
1341 struct symbol *symbol;
1344 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
1345 symbol = symbolhash[n];
1347 if (dump_sym(symbol))
1348 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
1349 symbol->crc, symbol->name,
1350 symbol->module->name,
1351 export_str(symbol->export));
1352 symbol = symbol->next;
1355 write_if_changed(&buf, fname);
1358 int main(int argc, char **argv)
1361 struct buffer buf = { };
1363 char *kernel_read = NULL, *module_read = NULL;
1364 char *dump_write = NULL;
1367 while ((opt = getopt(argc, argv, "i:I:mo:a")) != -1) {
1370 kernel_read = optarg;
1373 module_read = optarg;
1374 external_module = 1;
1380 dump_write = optarg;
1391 read_dump(kernel_read, 1);
1393 read_dump(module_read, 0);
1395 while (optind < argc) {
1396 read_symbols(argv[optind++]);
1399 for (mod = modules; mod; mod = mod->next) {
1405 for (mod = modules; mod; mod = mod->next) {
1411 add_header(&buf, mod);
1412 add_versions(&buf, mod);
1413 add_depends(&buf, mod, modules);
1414 add_moddevtable(&buf, mod);
1415 add_srcversion(&buf, mod);
1417 sprintf(fname, "%s.mod.c", mod->name);
1418 write_if_changed(&buf, fname);
1422 write_dump(dump_write);