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)
208 for (i = 0; export_list[i].export != export_unknown; i++) {
209 if (strcmp(export_list[i].str, s) == 0)
210 return export_list[i].export;
212 return export_unknown;
215 static enum export export_from_sec(struct elf_info *elf, Elf_Section sec)
217 if (sec == elf->export_sec)
219 else if (sec == elf->export_gpl_sec)
221 else if (sec == elf->export_gpl_future_sec)
222 return export_gpl_future;
224 return export_unknown;
228 * Add an exported symbol - it may have already been added without a
229 * CRC, in this case just update the CRC
231 static struct symbol *sym_add_exported(const char *name, struct module *mod,
234 struct symbol *s = find_symbol(name);
237 s = new_symbol(name, mod, export);
240 warn("%s: '%s' exported twice. Previous export "
241 "was in %s%s\n", mod->name, name,
243 is_vmlinux(s->module->name) ?"":".ko");
247 s->vmlinux = is_vmlinux(mod->name);
253 static void sym_update_crc(const char *name, struct module *mod,
254 unsigned int crc, enum export export)
256 struct symbol *s = find_symbol(name);
259 s = new_symbol(name, mod, export);
264 void *grab_file(const char *filename, unsigned long *size)
270 fd = open(filename, O_RDONLY);
271 if (fd < 0 || fstat(fd, &st) != 0)
275 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
278 if (map == MAP_FAILED)
284 * Return a copy of the next line in a mmap'ed file.
285 * spaces in the beginning of the line is trimmed away.
286 * Return a pointer to a static buffer.
288 char* get_next_line(unsigned long *pos, void *file, unsigned long size)
290 static char line[4096];
293 signed char *p = (signed char *)file + *pos;
296 for (; *pos < size ; (*pos)++)
298 if (skip && isspace(*p)) {
303 if (*p != '\n' && (*pos < size)) {
307 break; /* Too long, stop */
318 void release_file(void *file, unsigned long size)
323 static void parse_elf(struct elf_info *info, const char *filename)
326 Elf_Ehdr *hdr = info->hdr;
330 hdr = grab_file(filename, &info->size);
336 if (info->size < sizeof(*hdr))
339 /* Fix endianness in ELF header */
340 hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
341 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
342 hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
343 hdr->e_machine = TO_NATIVE(hdr->e_machine);
344 sechdrs = (void *)hdr + hdr->e_shoff;
345 info->sechdrs = sechdrs;
347 /* Fix endianness in section headers */
348 for (i = 0; i < hdr->e_shnum; i++) {
349 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
350 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
351 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
352 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
353 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
355 /* Find symbol table. */
356 for (i = 1; i < hdr->e_shnum; i++) {
357 const char *secstrings
358 = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
361 if (sechdrs[i].sh_offset > info->size)
363 secname = secstrings + sechdrs[i].sh_name;
364 if (strcmp(secname, ".modinfo") == 0) {
365 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
366 info->modinfo_len = sechdrs[i].sh_size;
367 } else if (strcmp(secname, "__ksymtab") == 0)
368 info->export_sec = i;
369 else if (strcmp(secname, "__ksymtab_gpl") == 0)
370 info->export_gpl_sec = i;
371 else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
372 info->export_gpl_future_sec = i;
374 if (sechdrs[i].sh_type != SHT_SYMTAB)
377 info->symtab_start = (void *)hdr + sechdrs[i].sh_offset;
378 info->symtab_stop = (void *)hdr + sechdrs[i].sh_offset
379 + sechdrs[i].sh_size;
380 info->strtab = (void *)hdr +
381 sechdrs[sechdrs[i].sh_link].sh_offset;
383 if (!info->symtab_start) {
384 fatal("%s has no symtab?\n", filename);
386 /* Fix endianness in symbols */
387 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
388 sym->st_shndx = TO_NATIVE(sym->st_shndx);
389 sym->st_name = TO_NATIVE(sym->st_name);
390 sym->st_value = TO_NATIVE(sym->st_value);
391 sym->st_size = TO_NATIVE(sym->st_size);
396 fatal("%s is truncated.\n", filename);
399 static void parse_elf_finish(struct elf_info *info)
401 release_file(info->hdr, info->size);
404 #define CRC_PFX MODULE_SYMBOL_PREFIX "__crc_"
405 #define KSYMTAB_PFX MODULE_SYMBOL_PREFIX "__ksymtab_"
407 static void handle_modversions(struct module *mod, struct elf_info *info,
408 Elf_Sym *sym, const char *symname)
411 enum export export = export_from_sec(info, sym->st_shndx);
413 switch (sym->st_shndx) {
415 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
419 if (memcmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
420 crc = (unsigned int) sym->st_value;
421 sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
426 /* undefined symbol */
427 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
428 ELF_ST_BIND(sym->st_info) != STB_WEAK)
430 /* ignore global offset table */
431 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
433 /* ignore __this_module, it will be resolved shortly */
434 if (strcmp(symname, MODULE_SYMBOL_PREFIX "__this_module") == 0)
436 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
437 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
438 /* add compatibility with older glibc */
439 #ifndef STT_SPARC_REGISTER
440 #define STT_SPARC_REGISTER STT_REGISTER
442 if (info->hdr->e_machine == EM_SPARC ||
443 info->hdr->e_machine == EM_SPARCV9) {
444 /* Ignore register directives. */
445 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
447 if (symname[0] == '.') {
448 char *munged = strdup(symname);
450 munged[1] = toupper(munged[1]);
456 if (memcmp(symname, MODULE_SYMBOL_PREFIX,
457 strlen(MODULE_SYMBOL_PREFIX)) == 0)
458 mod->unres = alloc_symbol(symname +
459 strlen(MODULE_SYMBOL_PREFIX),
460 ELF_ST_BIND(sym->st_info) == STB_WEAK,
464 /* All exported symbols */
465 if (memcmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
466 sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
469 if (strcmp(symname, MODULE_SYMBOL_PREFIX "init_module") == 0)
471 if (strcmp(symname, MODULE_SYMBOL_PREFIX "cleanup_module") == 0)
472 mod->has_cleanup = 1;
478 * Parse tag=value strings from .modinfo section
480 static char *next_string(char *string, unsigned long *secsize)
482 /* Skip non-zero chars */
485 if ((*secsize)-- <= 1)
489 /* Skip any zero padding. */
492 if ((*secsize)-- <= 1)
498 static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
499 const char *tag, char *info)
502 unsigned int taglen = strlen(tag);
503 unsigned long size = modinfo_len;
506 size -= info - (char *)modinfo;
507 modinfo = next_string(info, &size);
510 for (p = modinfo; p; p = next_string(p, &size)) {
511 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
512 return p + taglen + 1;
517 static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
521 return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
525 * Test if string s ends in string sub
528 static int strrcmp(const char *s, const char *sub)
536 sublen = strlen(sub);
538 if ((slen == 0) || (sublen == 0))
544 return memcmp(s + slen - sublen, sub, sublen);
548 * Whitelist to allow certain references to pass with no warning.
550 * If a module parameter is declared __initdata and permissions=0
551 * then this is legal despite the warning generated.
552 * We cannot see value of permissions here, so just ignore
554 * The pattern is identified by:
560 * Many drivers utilise a *driver container with references to
561 * add, remove, probe functions etc.
562 * These functions may often be marked __init and we do not want to
564 * the pattern is identified by:
565 * tosec = .init.text | .exit.text | .init.data
567 * atsym = *driver, *_template, *_sht, *_ops, *_probe, *probe_one
569 static int secref_whitelist(const char *tosec, const char *fromsec,
574 const char *pat2sym[] = {
576 "_template", /* scsi uses *_template a lot */
577 "_sht", /* scsi also used *_sht to some extent */
584 /* Check for pattern 1 */
585 if (strcmp(tosec, ".init.data") != 0)
587 if (strncmp(fromsec, ".data", strlen(".data")) != 0)
589 if (strncmp(atsym, "__param", strlen("__param")) != 0)
595 /* Check for pattern 2 */
596 if ((strcmp(tosec, ".init.text") != 0) &&
597 (strcmp(tosec, ".exit.text") != 0) &&
598 (strcmp(tosec, ".init.data") != 0))
600 if (strcmp(fromsec, ".data") != 0)
603 for (s = pat2sym; *s; s++)
604 if (strrcmp(atsym, *s) == 0)
611 * Find symbol based on relocation record info.
612 * In some cases the symbol supplied is a valid symbol so
613 * return refsym. If st_name != 0 we assume this is a valid symbol.
614 * In other cases the symbol needs to be looked up in the symbol table
615 * based on section and address.
617 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf_Addr addr,
622 if (relsym->st_name != 0)
624 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
625 if (sym->st_shndx != relsym->st_shndx)
627 if (sym->st_value == addr)
634 * Find symbols before or equal addr and after addr - in the section sec.
635 * If we find two symbols with equal offset prefer one with a valid name.
636 * The ELF format may have a better way to detect what type of symbol
637 * it is, but this works for now.
639 static void find_symbols_between(struct elf_info *elf, Elf_Addr addr,
641 Elf_Sym **before, Elf_Sym **after)
644 Elf_Ehdr *hdr = elf->hdr;
645 Elf_Addr beforediff = ~0;
646 Elf_Addr afterdiff = ~0;
647 const char *secstrings = (void *)hdr +
648 elf->sechdrs[hdr->e_shstrndx].sh_offset;
653 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
656 if (sym->st_shndx >= SHN_LORESERVE)
658 symsec = secstrings + elf->sechdrs[sym->st_shndx].sh_name;
659 if (strcmp(symsec, sec) != 0)
661 if (sym->st_value <= addr) {
662 if ((addr - sym->st_value) < beforediff) {
663 beforediff = addr - sym->st_value;
666 else if ((addr - sym->st_value) == beforediff) {
667 /* equal offset, valid name? */
668 const char *name = elf->strtab + sym->st_name;
669 if (name && strlen(name))
675 if ((sym->st_value - addr) < afterdiff) {
676 afterdiff = sym->st_value - addr;
679 else if ((sym->st_value - addr) == afterdiff) {
680 /* equal offset, valid name? */
681 const char *name = elf->strtab + sym->st_name;
682 if (name && strlen(name))
690 * Print a warning about a section mismatch.
691 * Try to find symbols near it so user can find it.
692 * Check whitelist before warning - it may be a false positive.
694 static void warn_sec_mismatch(const char *modname, const char *fromsec,
695 struct elf_info *elf, Elf_Sym *sym, Elf_Rela r)
697 const char *refsymname = "";
698 Elf_Sym *before, *after;
700 Elf_Ehdr *hdr = elf->hdr;
701 Elf_Shdr *sechdrs = elf->sechdrs;
702 const char *secstrings = (void *)hdr +
703 sechdrs[hdr->e_shstrndx].sh_offset;
704 const char *secname = secstrings + sechdrs[sym->st_shndx].sh_name;
706 find_symbols_between(elf, r.r_offset, fromsec, &before, &after);
708 refsym = find_elf_symbol(elf, r.r_addend, sym);
709 if (refsym && strlen(elf->strtab + refsym->st_name))
710 refsymname = elf->strtab + refsym->st_name;
712 /* check whitelist - we may ignore it */
714 secref_whitelist(secname, fromsec, elf->strtab + before->st_name))
717 if (before && after) {
718 warn("%s - Section mismatch: reference to %s:%s from %s "
719 "between '%s' (at offset 0x%llx) and '%s'\n",
720 modname, secname, refsymname, fromsec,
721 elf->strtab + before->st_name,
722 (long long)r.r_offset,
723 elf->strtab + after->st_name);
725 warn("%s - Section mismatch: reference to %s:%s from %s "
726 "after '%s' (at offset 0x%llx)\n",
727 modname, secname, refsymname, fromsec,
728 elf->strtab + before->st_name,
729 (long long)r.r_offset);
731 warn("%s - Section mismatch: reference to %s:%s from %s "
732 "before '%s' (at offset -0x%llx)\n",
733 modname, secname, refsymname, fromsec,
734 elf->strtab + after->st_name,
735 (long long)r.r_offset);
737 warn("%s - Section mismatch: reference to %s:%s from %s "
739 modname, secname, fromsec, refsymname,
740 (long long)r.r_offset);
745 * A module includes a number of sections that are discarded
746 * either when loaded or when used as built-in.
747 * For loaded modules all functions marked __init and all data
748 * marked __initdata will be discarded when the module has been intialized.
749 * Likewise for modules used built-in the sections marked __exit
750 * are discarded because __exit marked function are supposed to be called
751 * only when a moduel is unloaded which never happes for built-in modules.
752 * The check_sec_ref() function traverses all relocation records
753 * to find all references to a section that reference a section that will
754 * be discarded and warns about it.
756 static void check_sec_ref(struct module *mod, const char *modname,
757 struct elf_info *elf,
758 int section(const char*),
759 int section_ref_ok(const char *))
763 Elf_Ehdr *hdr = elf->hdr;
764 Elf_Shdr *sechdrs = elf->sechdrs;
765 const char *secstrings = (void *)hdr +
766 sechdrs[hdr->e_shstrndx].sh_offset;
768 /* Walk through all sections */
769 for (i = 0; i < hdr->e_shnum; i++) {
770 const char *name = secstrings + sechdrs[i].sh_name;
774 /* We want to process only relocation sections and not .init */
775 if (sechdrs[i].sh_type == SHT_RELA) {
777 Elf_Rela *start = (void *)hdr + sechdrs[i].sh_offset;
778 Elf_Rela *stop = (void*)start + sechdrs[i].sh_size;
779 name += strlen(".rela");
780 if (section_ref_ok(name))
783 for (rela = start; rela < stop; rela++) {
784 r.r_offset = TO_NATIVE(rela->r_offset);
785 #if KERNEL_ELFCLASS == ELFCLASS64
786 if (hdr->e_machine == EM_MIPS) {
787 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
788 r_sym = TO_NATIVE(r_sym);
790 r.r_info = TO_NATIVE(rela->r_info);
791 r_sym = ELF_R_SYM(r.r_info);
794 r.r_info = TO_NATIVE(rela->r_info);
795 r_sym = ELF_R_SYM(r.r_info);
797 r.r_addend = TO_NATIVE(rela->r_addend);
798 sym = elf->symtab_start + r_sym;
799 /* Skip special sections */
800 if (sym->st_shndx >= SHN_LORESERVE)
803 secname = secstrings +
804 sechdrs[sym->st_shndx].sh_name;
805 if (section(secname))
806 warn_sec_mismatch(modname, name,
809 } else if (sechdrs[i].sh_type == SHT_REL) {
811 Elf_Rel *start = (void *)hdr + sechdrs[i].sh_offset;
812 Elf_Rel *stop = (void*)start + sechdrs[i].sh_size;
813 name += strlen(".rel");
814 if (section_ref_ok(name))
817 for (rel = start; rel < stop; rel++) {
818 r.r_offset = TO_NATIVE(rel->r_offset);
819 #if KERNEL_ELFCLASS == ELFCLASS64
820 if (hdr->e_machine == EM_MIPS) {
821 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
822 r_sym = TO_NATIVE(r_sym);
824 r.r_info = TO_NATIVE(rel->r_info);
825 r_sym = ELF_R_SYM(r.r_info);
828 r.r_info = TO_NATIVE(rel->r_info);
829 r_sym = ELF_R_SYM(r.r_info);
832 sym = elf->symtab_start + r_sym;
833 /* Skip special sections */
834 if (sym->st_shndx >= SHN_LORESERVE)
837 secname = secstrings +
838 sechdrs[sym->st_shndx].sh_name;
839 if (section(secname))
840 warn_sec_mismatch(modname, name,
848 * Functions used only during module init is marked __init and is stored in
849 * a .init.text section. Likewise data is marked __initdata and stored in
850 * a .init.data section.
851 * If this section is one of these sections return 1
852 * See include/linux/init.h for the details
854 static int init_section(const char *name)
856 if (strcmp(name, ".init") == 0)
858 if (strncmp(name, ".init.", strlen(".init.")) == 0)
864 * Identify sections from which references to a .init section is OK.
866 * Unfortunately references to read only data that referenced .init
867 * sections had to be excluded. Almost all of these are false
868 * positives, they are created by gcc. The downside of excluding rodata
869 * is that there really are some user references from rodata to
870 * init code, e.g. drivers/video/vgacon.c:
872 * const struct consw vga_con = {
873 * con_startup: vgacon_startup,
875 * where vgacon_startup is __init. If you want to wade through the false
876 * positives, take out the check for rodata.
878 static int init_section_ref_ok(const char *name)
881 /* Absolute section names */
882 const char *namelist1[] = {
884 ".opd", /* see comment [OPD] at exit_section_ref_ok() */
885 ".toc1", /* used by ppc64 */
889 "__bug_table", /* used by powerpc for BUG() */
895 ".plt", /* seen on ARCH=um build on x86_64. Harmless */
898 /* Start of section names */
899 const char *namelist2[] = {
906 /* part of section name */
907 const char *namelist3 [] = {
908 ".unwind", /* sample: IA_64.unwind.init.text */
912 for (s = namelist1; *s; s++)
913 if (strcmp(*s, name) == 0)
915 for (s = namelist2; *s; s++)
916 if (strncmp(*s, name, strlen(*s)) == 0)
918 for (s = namelist3; *s; s++)
919 if (strstr(name, *s) != NULL)
925 * Functions used only during module exit is marked __exit and is stored in
926 * a .exit.text section. Likewise data is marked __exitdata and stored in
927 * a .exit.data section.
928 * If this section is one of these sections return 1
929 * See include/linux/init.h for the details
931 static int exit_section(const char *name)
933 if (strcmp(name, ".exit.text") == 0)
935 if (strcmp(name, ".exit.data") == 0)
942 * Identify sections from which references to a .exit section is OK.
944 * [OPD] Keith Ownes <kaos@sgi.com> commented:
945 * For our future {in}sanity, add a comment that this is the ppc .opd
946 * section, not the ia64 .opd section.
947 * ia64 .opd should not point to discarded sections.
948 * [.rodata] like for .init.text we ignore .rodata references -same reason
950 static int exit_section_ref_ok(const char *name)
953 /* Absolute section names */
954 const char *namelist1[] = {
959 ".opd", /* See comment [OPD] */
960 ".toc1", /* used by ppc64 */
963 "__bug_table", /* used by powerpc for BUG() */
968 ".plt", /* seen on ARCH=um build on x86_64. Harmless */
971 /* Start of section names */
972 const char *namelist2[] = {
976 /* part of section name */
977 const char *namelist3 [] = {
978 ".unwind", /* Sample: IA_64.unwind.exit.text */
982 for (s = namelist1; *s; s++)
983 if (strcmp(*s, name) == 0)
985 for (s = namelist2; *s; s++)
986 if (strncmp(*s, name, strlen(*s)) == 0)
988 for (s = namelist3; *s; s++)
989 if (strstr(name, *s) != NULL)
994 static void read_symbols(char *modname)
1000 struct elf_info info = { };
1003 parse_elf(&info, modname);
1005 mod = new_module(modname);
1007 /* When there's no vmlinux, don't print warnings about
1008 * unresolved symbols (since there'll be too many ;) */
1009 if (is_vmlinux(modname)) {
1014 license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1016 if (license_is_gpl_compatible(license))
1017 mod->gpl_compatible = 1;
1019 mod->gpl_compatible = 0;
1022 license = get_next_modinfo(info.modinfo, info.modinfo_len,
1023 "license", license);
1026 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1027 symname = info.strtab + sym->st_name;
1029 handle_modversions(mod, &info, sym, symname);
1030 handle_moddevtable(mod, &info, sym, symname);
1032 check_sec_ref(mod, modname, &info, init_section, init_section_ref_ok);
1033 check_sec_ref(mod, modname, &info, exit_section, exit_section_ref_ok);
1035 version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1037 maybe_frob_rcs_version(modname, version, info.modinfo,
1038 version - (char *)info.hdr);
1039 if (version || (all_versions && !is_vmlinux(modname)))
1040 get_src_version(modname, mod->srcversion,
1041 sizeof(mod->srcversion)-1);
1043 parse_elf_finish(&info);
1045 /* Our trick to get versioning for struct_module - it's
1046 * never passed as an argument to an exported function, so
1047 * the automatic versioning doesn't pick it up, but it's really
1048 * important anyhow */
1050 mod->unres = alloc_symbol("struct_module", 0, mod->unres);
1055 /* We first write the generated file into memory using the
1056 * following helper, then compare to the file on disk and
1057 * only update the later if anything changed */
1059 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
1060 const char *fmt, ...)
1067 len = vsnprintf(tmp, SZ, fmt, ap);
1068 buf_write(buf, tmp, len);
1072 void buf_write(struct buffer *buf, const char *s, int len)
1074 if (buf->size - buf->pos < len) {
1075 buf->size += len + SZ;
1076 buf->p = realloc(buf->p, buf->size);
1078 strncpy(buf->p + buf->pos, s, len);
1082 void check_license(struct module *mod)
1084 struct symbol *s, *exp;
1086 for (s = mod->unres; s; s = s->next) {
1087 const char *basename;
1088 if (mod->gpl_compatible == 1) {
1089 /* GPL-compatible modules may use all symbols */
1092 exp = find_symbol(s->name);
1093 if (!exp || exp->module == mod)
1095 basename = strrchr(mod->name, '/');
1098 switch (exp->export) {
1100 fatal("modpost: GPL-incompatible module %s "
1101 "uses GPL-only symbol '%s'\n",
1102 basename ? basename : mod->name,
1105 case export_gpl_future:
1106 warn("modpost: GPL-incompatible module %s "
1107 "uses future GPL-only symbol '%s'\n",
1108 basename ? basename : mod->name,
1111 case export_plain: /* ignore */ break;
1112 case export_unknown: /* ignore */ break;
1118 * Header for the generated file
1120 static void add_header(struct buffer *b, struct module *mod)
1122 buf_printf(b, "#include <linux/module.h>\n");
1123 buf_printf(b, "#include <linux/vermagic.h>\n");
1124 buf_printf(b, "#include <linux/compiler.h>\n");
1125 buf_printf(b, "\n");
1126 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
1127 buf_printf(b, "\n");
1128 buf_printf(b, "struct module __this_module\n");
1129 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
1130 buf_printf(b, " .name = KBUILD_MODNAME,\n");
1132 buf_printf(b, " .init = init_module,\n");
1133 if (mod->has_cleanup)
1134 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
1135 " .exit = cleanup_module,\n"
1137 buf_printf(b, "};\n");
1141 * Record CRCs for unresolved symbols
1143 static void add_versions(struct buffer *b, struct module *mod)
1145 struct symbol *s, *exp;
1147 for (s = mod->unres; s; s = s->next) {
1148 exp = find_symbol(s->name);
1149 if (!exp || exp->module == mod) {
1150 if (have_vmlinux && !s->weak)
1151 warn("\"%s\" [%s.ko] undefined!\n",
1152 s->name, mod->name);
1155 s->module = exp->module;
1156 s->crc_valid = exp->crc_valid;
1163 buf_printf(b, "\n");
1164 buf_printf(b, "static const struct modversion_info ____versions[]\n");
1165 buf_printf(b, "__attribute_used__\n");
1166 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
1168 for (s = mod->unres; s; s = s->next) {
1172 if (!s->crc_valid) {
1173 warn("\"%s\" [%s.ko] has no CRC!\n",
1174 s->name, mod->name);
1177 buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name);
1180 buf_printf(b, "};\n");
1183 static void add_depends(struct buffer *b, struct module *mod,
1184 struct module *modules)
1190 for (m = modules; m; m = m->next) {
1191 m->seen = is_vmlinux(m->name);
1194 buf_printf(b, "\n");
1195 buf_printf(b, "static const char __module_depends[]\n");
1196 buf_printf(b, "__attribute_used__\n");
1197 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
1198 buf_printf(b, "\"depends=");
1199 for (s = mod->unres; s; s = s->next) {
1203 if (s->module->seen)
1206 s->module->seen = 1;
1207 buf_printf(b, "%s%s", first ? "" : ",",
1208 strrchr(s->module->name, '/') + 1);
1211 buf_printf(b, "\";\n");
1214 static void add_srcversion(struct buffer *b, struct module *mod)
1216 if (mod->srcversion[0]) {
1217 buf_printf(b, "\n");
1218 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
1223 static void write_if_changed(struct buffer *b, const char *fname)
1229 file = fopen(fname, "r");
1233 if (fstat(fileno(file), &st) < 0)
1236 if (st.st_size != b->pos)
1239 tmp = NOFAIL(malloc(b->pos));
1240 if (fread(tmp, 1, b->pos, file) != b->pos)
1243 if (memcmp(tmp, b->p, b->pos) != 0)
1255 file = fopen(fname, "w");
1260 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
1267 /* parse Module.symvers file. line format:
1268 * 0x12345678<tab>symbol<tab>module[<tab>export]
1270 static void read_dump(const char *fname, unsigned int kernel)
1272 unsigned long size, pos = 0;
1273 void *file = grab_file(fname, &size);
1277 /* No symbol versions, silently ignore */
1280 while ((line = get_next_line(&pos, file, size))) {
1281 char *symname, *modname, *d, *export;
1286 if (!(symname = strchr(line, '\t')))
1289 if (!(modname = strchr(symname, '\t')))
1292 if (!(export = strchr(modname, '\t')))
1295 crc = strtoul(line, &d, 16);
1296 if (*symname == '\0' || *modname == '\0' || *d != '\0')
1299 if (!(mod = find_module(modname))) {
1300 if (is_vmlinux(modname)) {
1303 mod = new_module(NOFAIL(strdup(modname)));
1306 s = sym_add_exported(symname, mod, export_no(export));
1309 sym_update_crc(symname, mod, crc, export_no(export));
1313 fatal("parse error in symbol dump file\n");
1316 /* For normal builds always dump all symbols.
1317 * For external modules only dump symbols
1318 * that are not read from kernel Module.symvers.
1320 static int dump_sym(struct symbol *sym)
1322 if (!external_module)
1324 if (sym->vmlinux || sym->kernel)
1329 static void write_dump(const char *fname)
1331 struct buffer buf = { };
1332 struct symbol *symbol;
1335 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
1336 symbol = symbolhash[n];
1338 if (dump_sym(symbol))
1339 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
1340 symbol->crc, symbol->name,
1341 symbol->module->name,
1342 export_str(symbol->export));
1343 symbol = symbol->next;
1346 write_if_changed(&buf, fname);
1349 int main(int argc, char **argv)
1352 struct buffer buf = { };
1354 char *kernel_read = NULL, *module_read = NULL;
1355 char *dump_write = NULL;
1358 while ((opt = getopt(argc, argv, "i:I:mo:a")) != -1) {
1361 kernel_read = optarg;
1364 module_read = optarg;
1365 external_module = 1;
1371 dump_write = optarg;
1382 read_dump(kernel_read, 1);
1384 read_dump(module_read, 0);
1386 while (optind < argc) {
1387 read_symbols(argv[optind++]);
1390 for (mod = modules; mod; mod = mod->next) {
1396 for (mod = modules; mod; mod = mod->next) {
1402 add_header(&buf, mod);
1403 add_versions(&buf, mod);
1404 add_depends(&buf, mod, modules);
1405 add_moddevtable(&buf, mod);
1406 add_srcversion(&buf, mod);
1408 sprintf(fname, "%s.mod.c", mod->name);
1409 write_if_changed(&buf, fname);
1413 write_dump(dump_write);