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 /* Only warn about unresolved symbols */
27 static int warn_unresolved = 0;
28 /* How a symbol is exported */
30 export_plain, export_unused, export_gpl,
31 export_unused_gpl, export_gpl_future, export_unknown
34 void fatal(const char *fmt, ...)
38 fprintf(stderr, "FATAL: ");
40 va_start(arglist, fmt);
41 vfprintf(stderr, fmt, arglist);
47 void warn(const char *fmt, ...)
51 fprintf(stderr, "WARNING: ");
53 va_start(arglist, fmt);
54 vfprintf(stderr, fmt, arglist);
58 void merror(const char *fmt, ...)
62 fprintf(stderr, "ERROR: ");
64 va_start(arglist, fmt);
65 vfprintf(stderr, fmt, arglist);
69 static int is_vmlinux(const char *modname)
73 if ((myname = strrchr(modname, '/')))
78 return strcmp(myname, "vmlinux") == 0;
81 void *do_nofail(void *ptr, const char *expr)
84 fatal("modpost: Memory allocation failure: %s.\n", expr);
89 /* A list of all modules we processed */
91 static struct module *modules;
93 static struct module *find_module(char *modname)
97 for (mod = modules; mod; mod = mod->next)
98 if (strcmp(mod->name, modname) == 0)
103 static struct module *new_module(char *modname)
108 mod = NOFAIL(malloc(sizeof(*mod)));
109 memset(mod, 0, sizeof(*mod));
110 p = NOFAIL(strdup(modname));
112 /* strip trailing .o */
113 if ((s = strrchr(p, '.')) != NULL)
114 if (strcmp(s, ".o") == 0)
119 mod->gpl_compatible = -1;
126 /* A hash of all exported symbols,
127 * struct symbol is also used for lists of unresolved symbols */
129 #define SYMBOL_HASH_SIZE 1024
133 struct module *module;
137 unsigned int vmlinux:1; /* 1 if symbol is defined in vmlinux */
138 unsigned int kernel:1; /* 1 if symbol is from kernel
139 * (only for external modules) **/
140 unsigned int preloaded:1; /* 1 if symbol from Module.symvers */
141 enum export export; /* Type of export */
145 static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
147 /* This is based on the hash agorithm from gdbm, via tdb */
148 static inline unsigned int tdb_hash(const char *name)
150 unsigned value; /* Used to compute the hash value. */
151 unsigned i; /* Used to cycle through random values. */
153 /* Set the initial value from the key size. */
154 for (value = 0x238F13AF * strlen(name), i=0; name[i]; i++)
155 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
157 return (1103515243 * value + 12345);
161 * Allocate a new symbols for use in the hash of exported symbols or
162 * the list of unresolved symbols per module
164 static struct symbol *alloc_symbol(const char *name, unsigned int weak,
167 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
169 memset(s, 0, sizeof(*s));
170 strcpy(s->name, name);
176 /* For the hash of exported symbols */
177 static struct symbol *new_symbol(const char *name, struct module *module,
183 hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
184 new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
185 new->module = module;
186 new->export = export;
190 static struct symbol *find_symbol(const char *name)
194 /* For our purposes, .foo matches foo. PPC64 needs this. */
198 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s=s->next) {
199 if (strcmp(s->name, name) == 0)
209 { .str = "EXPORT_SYMBOL", .export = export_plain },
210 { .str = "EXPORT_UNUSED_SYMBOL", .export = export_unused },
211 { .str = "EXPORT_SYMBOL_GPL", .export = export_gpl },
212 { .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
213 { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
214 { .str = "(unknown)", .export = export_unknown },
218 static const char *export_str(enum export ex)
220 return export_list[ex].str;
223 static enum export export_no(const char * s)
227 return export_unknown;
228 for (i = 0; export_list[i].export != export_unknown; i++) {
229 if (strcmp(export_list[i].str, s) == 0)
230 return export_list[i].export;
232 return export_unknown;
235 static enum export export_from_sec(struct elf_info *elf, Elf_Section sec)
237 if (sec == elf->export_sec)
239 else if (sec == elf->export_unused_sec)
240 return export_unused;
241 else if (sec == elf->export_gpl_sec)
243 else if (sec == elf->export_unused_gpl_sec)
244 return export_unused_gpl;
245 else if (sec == elf->export_gpl_future_sec)
246 return export_gpl_future;
248 return export_unknown;
252 * Add an exported symbol - it may have already been added without a
253 * CRC, in this case just update the CRC
255 static struct symbol *sym_add_exported(const char *name, struct module *mod,
258 struct symbol *s = find_symbol(name);
261 s = new_symbol(name, mod, export);
264 warn("%s: '%s' exported twice. Previous export "
265 "was in %s%s\n", mod->name, name,
267 is_vmlinux(s->module->name) ?"":".ko");
271 s->vmlinux = is_vmlinux(mod->name);
277 static void sym_update_crc(const char *name, struct module *mod,
278 unsigned int crc, enum export export)
280 struct symbol *s = find_symbol(name);
283 s = new_symbol(name, mod, export);
288 void *grab_file(const char *filename, unsigned long *size)
294 fd = open(filename, O_RDONLY);
295 if (fd < 0 || fstat(fd, &st) != 0)
299 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
302 if (map == MAP_FAILED)
308 * Return a copy of the next line in a mmap'ed file.
309 * spaces in the beginning of the line is trimmed away.
310 * Return a pointer to a static buffer.
312 char* get_next_line(unsigned long *pos, void *file, unsigned long size)
314 static char line[4096];
317 signed char *p = (signed char *)file + *pos;
320 for (; *pos < size ; (*pos)++)
322 if (skip && isspace(*p)) {
327 if (*p != '\n' && (*pos < size)) {
331 break; /* Too long, stop */
342 void release_file(void *file, unsigned long size)
347 static int parse_elf(struct elf_info *info, const char *filename)
354 hdr = grab_file(filename, &info->size);
360 if (info->size < sizeof(*hdr)) {
361 /* file too small, assume this is an empty .o file */
364 /* Is this a valid ELF file? */
365 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
366 (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
367 (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
368 (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
369 /* Not an ELF file - silently ignore it */
372 /* Fix endianness in ELF header */
373 hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
374 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
375 hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
376 hdr->e_machine = TO_NATIVE(hdr->e_machine);
377 hdr->e_type = TO_NATIVE(hdr->e_type);
378 sechdrs = (void *)hdr + hdr->e_shoff;
379 info->sechdrs = sechdrs;
381 /* Fix endianness in section headers */
382 for (i = 0; i < hdr->e_shnum; i++) {
383 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
384 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
385 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
386 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
387 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
388 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info);
389 sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr);
391 /* Find symbol table. */
392 for (i = 1; i < hdr->e_shnum; i++) {
393 const char *secstrings
394 = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
397 if (sechdrs[i].sh_offset > info->size) {
398 fatal("%s is truncated. sechdrs[i].sh_offset=%u > sizeof(*hrd)=%ul\n", filename, (unsigned int)sechdrs[i].sh_offset, sizeof(*hdr));
401 secname = secstrings + sechdrs[i].sh_name;
402 if (strcmp(secname, ".modinfo") == 0) {
403 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
404 info->modinfo_len = sechdrs[i].sh_size;
405 } else if (strcmp(secname, "__ksymtab") == 0)
406 info->export_sec = i;
407 else if (strcmp(secname, "__ksymtab_unused") == 0)
408 info->export_unused_sec = i;
409 else if (strcmp(secname, "__ksymtab_gpl") == 0)
410 info->export_gpl_sec = i;
411 else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
412 info->export_unused_gpl_sec = i;
413 else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
414 info->export_gpl_future_sec = i;
416 if (sechdrs[i].sh_type != SHT_SYMTAB)
419 info->symtab_start = (void *)hdr + sechdrs[i].sh_offset;
420 info->symtab_stop = (void *)hdr + sechdrs[i].sh_offset
421 + sechdrs[i].sh_size;
422 info->strtab = (void *)hdr +
423 sechdrs[sechdrs[i].sh_link].sh_offset;
425 if (!info->symtab_start) {
426 fatal("%s has no symtab?\n", filename);
428 /* Fix endianness in symbols */
429 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
430 sym->st_shndx = TO_NATIVE(sym->st_shndx);
431 sym->st_name = TO_NATIVE(sym->st_name);
432 sym->st_value = TO_NATIVE(sym->st_value);
433 sym->st_size = TO_NATIVE(sym->st_size);
438 static void parse_elf_finish(struct elf_info *info)
440 release_file(info->hdr, info->size);
443 #define CRC_PFX MODULE_SYMBOL_PREFIX "__crc_"
444 #define KSYMTAB_PFX MODULE_SYMBOL_PREFIX "__ksymtab_"
446 static void handle_modversions(struct module *mod, struct elf_info *info,
447 Elf_Sym *sym, const char *symname)
450 enum export export = export_from_sec(info, sym->st_shndx);
452 switch (sym->st_shndx) {
454 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
458 if (memcmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
459 crc = (unsigned int) sym->st_value;
460 sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
465 /* undefined symbol */
466 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
467 ELF_ST_BIND(sym->st_info) != STB_WEAK)
469 /* ignore global offset table */
470 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
472 /* ignore __this_module, it will be resolved shortly */
473 if (strcmp(symname, MODULE_SYMBOL_PREFIX "__this_module") == 0)
475 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
476 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
477 /* add compatibility with older glibc */
478 #ifndef STT_SPARC_REGISTER
479 #define STT_SPARC_REGISTER STT_REGISTER
481 if (info->hdr->e_machine == EM_SPARC ||
482 info->hdr->e_machine == EM_SPARCV9) {
483 /* Ignore register directives. */
484 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
486 if (symname[0] == '.') {
487 char *munged = strdup(symname);
489 munged[1] = toupper(munged[1]);
495 if (memcmp(symname, MODULE_SYMBOL_PREFIX,
496 strlen(MODULE_SYMBOL_PREFIX)) == 0)
497 mod->unres = alloc_symbol(symname +
498 strlen(MODULE_SYMBOL_PREFIX),
499 ELF_ST_BIND(sym->st_info) == STB_WEAK,
503 /* All exported symbols */
504 if (memcmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
505 sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
508 if (strcmp(symname, MODULE_SYMBOL_PREFIX "init_module") == 0)
510 if (strcmp(symname, MODULE_SYMBOL_PREFIX "cleanup_module") == 0)
511 mod->has_cleanup = 1;
517 * Parse tag=value strings from .modinfo section
519 static char *next_string(char *string, unsigned long *secsize)
521 /* Skip non-zero chars */
524 if ((*secsize)-- <= 1)
528 /* Skip any zero padding. */
531 if ((*secsize)-- <= 1)
537 static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
538 const char *tag, char *info)
541 unsigned int taglen = strlen(tag);
542 unsigned long size = modinfo_len;
545 size -= info - (char *)modinfo;
546 modinfo = next_string(info, &size);
549 for (p = modinfo; p; p = next_string(p, &size)) {
550 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
551 return p + taglen + 1;
556 static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
560 return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
564 * Test if string s ends in string sub
567 static int strrcmp(const char *s, const char *sub)
575 sublen = strlen(sub);
577 if ((slen == 0) || (sublen == 0))
583 return memcmp(s + slen - sublen, sub, sublen);
587 * Whitelist to allow certain references to pass with no warning.
590 * Do not warn if funtion/data are marked with __init_refok/__initdata_refok.
591 * The pattern is identified by:
592 * fromsec = .text.init.refok | .data.init.refok
595 * If a module parameter is declared __initdata and permissions=0
596 * then this is legal despite the warning generated.
597 * We cannot see value of permissions here, so just ignore
599 * The pattern is identified by:
605 * Many drivers utilise a *driver container with references to
606 * add, remove, probe functions etc.
607 * These functions may often be marked __init and we do not want to
609 * the pattern is identified by:
610 * tosec = .init.text | .exit.text | .init.data
612 * atsym = *driver, *_template, *_sht, *_ops, *_probe, *probe_one, *_console
615 * Whitelist all references from .pci_fixup* section to .init.text
616 * This is part of the PCI init when built-in
619 * Whitelist all refereces from .text.head to .init.data
620 * Whitelist all refereces from .text.head to .init.text
623 * Some symbols belong to init section but still it is ok to reference
624 * these from non-init sections as these symbols don't have any memory
625 * allocated for them and symbol address and value are same. So even
626 * if init section is freed, its ok to reference those symbols.
627 * For ex. symbols marking the init section boundaries.
628 * This pattern is identified by
629 * refsymname = __init_begin, _sinittext, _einittext
632 * Logos used in drivers/video/logo reside in __initdata but the
633 * funtion that references them are EXPORT_SYMBOL() so cannot be
634 * marker __init. So we whitelist them here.
641 * ia64 has machvec table for each platform and
642 * powerpc has a machine desc table for each platform.
643 * It is mixture of function pointers of .init.text and .text.
644 * fromsec = .machvec | .machine.desc
646 static int secref_whitelist(const char *modname, const char *tosec,
647 const char *fromsec, const char *atsym,
648 const char *refsymname)
652 const char *pat2sym[] = {
654 "_template", /* scsi uses *_template a lot */
655 "_sht", /* scsi also used *_sht to some extent */
664 const char *pat3refsym[] = {
671 /* Check for pattern 0 */
672 if ((strcmp(fromsec, ".text.init.refok") == 0) ||
673 (strcmp(fromsec, ".data.init.refok") == 0))
676 /* Check for pattern 1 */
677 if (strcmp(tosec, ".init.data") != 0)
679 if (strncmp(fromsec, ".data", strlen(".data")) != 0)
681 if (strncmp(atsym, "__param", strlen("__param")) != 0)
687 /* Check for pattern 2 */
688 if ((strcmp(tosec, ".init.text") != 0) &&
689 (strcmp(tosec, ".exit.text") != 0) &&
690 (strcmp(tosec, ".init.data") != 0))
692 if (strcmp(fromsec, ".data") != 0)
695 for (s = pat2sym; *s; s++)
696 if (strrcmp(atsym, *s) == 0)
701 /* Check for pattern 3 */
702 if ((strncmp(fromsec, ".pci_fixup", strlen(".pci_fixup")) == 0) &&
703 (strcmp(tosec, ".init.text") == 0))
706 /* Check for pattern 4 */
707 if ((strcmp(fromsec, ".text.head") == 0) &&
708 ((strcmp(tosec, ".init.data") == 0) ||
709 (strcmp(tosec, ".init.text") == 0)))
712 /* Check for pattern 5 */
713 for (s = pat3refsym; *s; s++)
714 if (strcmp(refsymname, *s) == 0)
717 /* Check for pattern 7 */
718 if ((strcmp(tosec, ".init.data") == 0) &&
719 (strncmp(fromsec, ".text", strlen(".text")) == 0) &&
720 (strncmp(refsymname, "logo_", strlen("logo_")) == 0))
723 /* Check for pattern 10 */
724 if ((strcmp(fromsec, ".machvec") == 0) ||
725 (strcmp(fromsec, ".machine.desc") == 0))
732 * Find symbol based on relocation record info.
733 * In some cases the symbol supplied is a valid symbol so
734 * return refsym. If st_name != 0 we assume this is a valid symbol.
735 * In other cases the symbol needs to be looked up in the symbol table
736 * based on section and address.
738 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf_Addr addr,
743 if (relsym->st_name != 0)
745 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
746 if (sym->st_shndx != relsym->st_shndx)
748 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
750 if (sym->st_value == addr)
756 static inline int is_arm_mapping_symbol(const char *str)
758 return str[0] == '$' && strchr("atd", str[1])
759 && (str[2] == '\0' || str[2] == '.');
763 * If there's no name there, ignore it; likewise, ignore it if it's
764 * one of the magic symbols emitted used by current ARM tools.
766 * Otherwise if find_symbols_between() returns those symbols, they'll
767 * fail the whitelist tests and cause lots of false alarms ... fixable
768 * only by merging __exit and __init sections into __text, bloating
769 * the kernel (which is especially evil on embedded platforms).
771 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
773 const char *name = elf->strtab + sym->st_name;
775 if (!name || !strlen(name))
777 return !is_arm_mapping_symbol(name);
781 * Find symbols before or equal addr and after addr - in the section sec.
782 * If we find two symbols with equal offset prefer one with a valid name.
783 * The ELF format may have a better way to detect what type of symbol
784 * it is, but this works for now.
786 static void find_symbols_between(struct elf_info *elf, Elf_Addr addr,
788 Elf_Sym **before, Elf_Sym **after)
791 Elf_Ehdr *hdr = elf->hdr;
792 Elf_Addr beforediff = ~0;
793 Elf_Addr afterdiff = ~0;
794 const char *secstrings = (void *)hdr +
795 elf->sechdrs[hdr->e_shstrndx].sh_offset;
800 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
803 if (sym->st_shndx >= SHN_LORESERVE)
805 symsec = secstrings + elf->sechdrs[sym->st_shndx].sh_name;
806 if (strcmp(symsec, sec) != 0)
808 if (!is_valid_name(elf, sym))
810 if (sym->st_value <= addr) {
811 if ((addr - sym->st_value) < beforediff) {
812 beforediff = addr - sym->st_value;
815 else if ((addr - sym->st_value) == beforediff) {
821 if ((sym->st_value - addr) < afterdiff) {
822 afterdiff = sym->st_value - addr;
825 else if ((sym->st_value - addr) == afterdiff) {
833 * Print a warning about a section mismatch.
834 * Try to find symbols near it so user can find it.
835 * Check whitelist before warning - it may be a false positive.
837 static void warn_sec_mismatch(const char *modname, const char *fromsec,
838 struct elf_info *elf, Elf_Sym *sym, Elf_Rela r)
840 const char *refsymname = "";
841 Elf_Sym *before, *after;
843 Elf_Ehdr *hdr = elf->hdr;
844 Elf_Shdr *sechdrs = elf->sechdrs;
845 const char *secstrings = (void *)hdr +
846 sechdrs[hdr->e_shstrndx].sh_offset;
847 const char *secname = secstrings + sechdrs[sym->st_shndx].sh_name;
849 find_symbols_between(elf, r.r_offset, fromsec, &before, &after);
851 refsym = find_elf_symbol(elf, r.r_addend, sym);
852 if (refsym && strlen(elf->strtab + refsym->st_name))
853 refsymname = elf->strtab + refsym->st_name;
855 /* check whitelist - we may ignore it */
857 secref_whitelist(modname, secname, fromsec,
858 elf->strtab + before->st_name, refsymname))
861 if (before && after) {
862 warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s "
863 "(between '%s' and '%s')\n",
864 modname, fromsec, (unsigned long long)r.r_offset,
866 elf->strtab + before->st_name,
867 elf->strtab + after->st_name);
869 warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s "
871 modname, fromsec, (unsigned long long)r.r_offset,
873 elf->strtab + before->st_name);
875 warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s "
876 "before '%s' (at offset -0x%llx)\n",
877 modname, fromsec, (unsigned long long)r.r_offset,
879 elf->strtab + after->st_name);
881 warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s\n",
882 modname, fromsec, (unsigned long long)r.r_offset,
883 secname, refsymname);
887 static unsigned int *reloc_location(struct elf_info *elf,
888 int rsection, Elf_Rela *r)
890 Elf_Shdr *sechdrs = elf->sechdrs;
891 int section = sechdrs[rsection].sh_info;
893 return (void *)elf->hdr + sechdrs[section].sh_offset +
894 (r->r_offset - sechdrs[section].sh_addr);
897 static int addend_386_rel(struct elf_info *elf, int rsection, Elf_Rela *r)
899 unsigned int r_typ = ELF_R_TYPE(r->r_info);
900 unsigned int *location = reloc_location(elf, rsection, r);
904 r->r_addend = TO_NATIVE(*location);
907 r->r_addend = TO_NATIVE(*location) + 4;
908 /* For CONFIG_RELOCATABLE=y */
909 if (elf->hdr->e_type == ET_EXEC)
910 r->r_addend += r->r_offset;
916 static int addend_arm_rel(struct elf_info *elf, int rsection, Elf_Rela *r)
918 unsigned int r_typ = ELF_R_TYPE(r->r_info);
922 /* From ARM ABI: (S + A) | T */
923 r->r_addend = (int)(long)(elf->symtab_start + ELF_R_SYM(r->r_info));
926 /* From ARM ABI: ((S + A) | T) - P */
927 r->r_addend = (int)(long)(elf->hdr + elf->sechdrs[rsection].sh_offset +
928 (r->r_offset - elf->sechdrs[rsection].sh_addr));
936 static int addend_mips_rel(struct elf_info *elf, int rsection, Elf_Rela *r)
938 unsigned int r_typ = ELF_R_TYPE(r->r_info);
939 unsigned int *location = reloc_location(elf, rsection, r);
942 if (r_typ == R_MIPS_HI16)
943 return 1; /* skip this */
944 inst = TO_NATIVE(*location);
947 r->r_addend = inst & 0xffff;
950 r->r_addend = (inst & 0x03ffffff) << 2;
960 * A module includes a number of sections that are discarded
961 * either when loaded or when used as built-in.
962 * For loaded modules all functions marked __init and all data
963 * marked __initdata will be discarded when the module has been intialized.
964 * Likewise for modules used built-in the sections marked __exit
965 * are discarded because __exit marked function are supposed to be called
966 * only when a moduel is unloaded which never happes for built-in modules.
967 * The check_sec_ref() function traverses all relocation records
968 * to find all references to a section that reference a section that will
969 * be discarded and warns about it.
971 static void check_sec_ref(struct module *mod, const char *modname,
972 struct elf_info *elf,
973 int section(const char*),
974 int section_ref_ok(const char *))
978 Elf_Ehdr *hdr = elf->hdr;
979 Elf_Shdr *sechdrs = elf->sechdrs;
980 const char *secstrings = (void *)hdr +
981 sechdrs[hdr->e_shstrndx].sh_offset;
983 /* Walk through all sections */
984 for (i = 0; i < hdr->e_shnum; i++) {
985 const char *name = secstrings + sechdrs[i].sh_name;
989 /* We want to process only relocation sections and not .init */
990 if (sechdrs[i].sh_type == SHT_RELA) {
992 Elf_Rela *start = (void *)hdr + sechdrs[i].sh_offset;
993 Elf_Rela *stop = (void*)start + sechdrs[i].sh_size;
994 name += strlen(".rela");
995 if (section_ref_ok(name))
998 for (rela = start; rela < stop; rela++) {
999 r.r_offset = TO_NATIVE(rela->r_offset);
1000 #if KERNEL_ELFCLASS == ELFCLASS64
1001 if (hdr->e_machine == EM_MIPS) {
1003 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1004 r_sym = TO_NATIVE(r_sym);
1005 r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1006 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1008 r.r_info = TO_NATIVE(rela->r_info);
1009 r_sym = ELF_R_SYM(r.r_info);
1012 r.r_info = TO_NATIVE(rela->r_info);
1013 r_sym = ELF_R_SYM(r.r_info);
1015 r.r_addend = TO_NATIVE(rela->r_addend);
1016 sym = elf->symtab_start + r_sym;
1017 /* Skip special sections */
1018 if (sym->st_shndx >= SHN_LORESERVE)
1021 secname = secstrings +
1022 sechdrs[sym->st_shndx].sh_name;
1023 if (section(secname))
1024 warn_sec_mismatch(modname, name,
1027 } else if (sechdrs[i].sh_type == SHT_REL) {
1029 Elf_Rel *start = (void *)hdr + sechdrs[i].sh_offset;
1030 Elf_Rel *stop = (void*)start + sechdrs[i].sh_size;
1031 name += strlen(".rel");
1032 if (section_ref_ok(name))
1035 for (rel = start; rel < stop; rel++) {
1036 r.r_offset = TO_NATIVE(rel->r_offset);
1037 #if KERNEL_ELFCLASS == ELFCLASS64
1038 if (hdr->e_machine == EM_MIPS) {
1040 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1041 r_sym = TO_NATIVE(r_sym);
1042 r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1043 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1045 r.r_info = TO_NATIVE(rel->r_info);
1046 r_sym = ELF_R_SYM(r.r_info);
1049 r.r_info = TO_NATIVE(rel->r_info);
1050 r_sym = ELF_R_SYM(r.r_info);
1053 switch (hdr->e_machine) {
1055 if (addend_386_rel(elf, i, &r))
1059 if(addend_arm_rel(elf, i, &r))
1063 if (addend_mips_rel(elf, i, &r))
1067 sym = elf->symtab_start + r_sym;
1068 /* Skip special sections */
1069 if (sym->st_shndx >= SHN_LORESERVE)
1072 secname = secstrings +
1073 sechdrs[sym->st_shndx].sh_name;
1074 if (section(secname))
1075 warn_sec_mismatch(modname, name,
1083 * Identify sections from which references to either a
1084 * .init or a .exit section is OK.
1086 * [OPD] Keith Ownes <kaos@sgi.com> commented:
1087 * For our future {in}sanity, add a comment that this is the ppc .opd
1088 * section, not the ia64 .opd section.
1089 * ia64 .opd should not point to discarded sections.
1090 * [.rodata] like for .init.text we ignore .rodata references -same reason
1092 static int initexit_section_ref_ok(const char *name)
1095 /* Absolute section names */
1096 const char *namelist1[] = {
1097 "__bug_table", /* used by powerpc for BUG() */
1100 ".cranges", /* used by sh64 */
1102 ".opd", /* See comment [OPD] */
1103 ".parainstructions",
1105 ".plt", /* seen on ARCH=um build on x86_64. Harmless */
1110 /* Start of section names */
1111 const char *namelist2[] = {
1114 ".note", /* ignore ELF notes - may contain anything */
1115 ".got", /* powerpc - global offset table */
1116 ".toc", /* powerpc - table of contents */
1119 /* part of section name */
1120 const char *namelist3 [] = {
1121 ".unwind", /* Sample: IA_64.unwind.exit.text */
1125 for (s = namelist1; *s; s++)
1126 if (strcmp(*s, name) == 0)
1128 for (s = namelist2; *s; s++)
1129 if (strncmp(*s, name, strlen(*s)) == 0)
1131 for (s = namelist3; *s; s++)
1132 if (strstr(name, *s) != NULL)
1138 * Functions used only during module init is marked __init and is stored in
1139 * a .init.text section. Likewise data is marked __initdata and stored in
1140 * a .init.data section.
1141 * If this section is one of these sections return 1
1142 * See include/linux/init.h for the details
1144 static int init_section(const char *name)
1146 if (strcmp(name, ".init") == 0)
1148 if (strncmp(name, ".init.", strlen(".init.")) == 0)
1154 * Identify sections from which references to a .init section is OK.
1156 * Unfortunately references to read only data that referenced .init
1157 * sections had to be excluded. Almost all of these are false
1158 * positives, they are created by gcc. The downside of excluding rodata
1159 * is that there really are some user references from rodata to
1160 * init code, e.g. drivers/video/vgacon.c:
1162 * const struct consw vga_con = {
1163 * con_startup: vgacon_startup,
1165 * where vgacon_startup is __init. If you want to wade through the false
1166 * positives, take out the check for rodata.
1168 static int init_section_ref_ok(const char *name)
1171 /* Absolute section names */
1172 const char *namelist1[] = {
1173 "__ftr_fixup", /* powerpc cpu feature fixup */
1174 "__fw_ftr_fixup", /* powerpc firmware feature fixup */
1176 ".data.rel.ro", /* used by parisc64 */
1181 /* Start of section names */
1182 const char *namelist2[] = {
1189 if (initexit_section_ref_ok(name))
1192 for (s = namelist1; *s; s++)
1193 if (strcmp(*s, name) == 0)
1195 for (s = namelist2; *s; s++)
1196 if (strncmp(*s, name, strlen(*s)) == 0)
1199 /* If section name ends with ".init" we allow references
1200 * as is the case with .initcallN.init, .early_param.init, .taglist.init etc
1202 if (strrcmp(name, ".init") == 0)
1208 * Functions used only during module exit is marked __exit and is stored in
1209 * a .exit.text section. Likewise data is marked __exitdata and stored in
1210 * a .exit.data section.
1211 * If this section is one of these sections return 1
1212 * See include/linux/init.h for the details
1214 static int exit_section(const char *name)
1216 if (strcmp(name, ".exit.text") == 0)
1218 if (strcmp(name, ".exit.data") == 0)
1225 * Identify sections from which references to a .exit section is OK.
1227 static int exit_section_ref_ok(const char *name)
1230 /* Absolute section names */
1231 const char *namelist1[] = {
1240 if (initexit_section_ref_ok(name))
1243 for (s = namelist1; *s; s++)
1244 if (strcmp(*s, name) == 0)
1249 static void read_symbols(char *modname)
1251 const char *symname;
1255 struct elf_info info = { };
1258 if (!parse_elf(&info, modname))
1261 mod = new_module(modname);
1263 /* When there's no vmlinux, don't print warnings about
1264 * unresolved symbols (since there'll be too many ;) */
1265 if (is_vmlinux(modname)) {
1270 license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1272 if (license_is_gpl_compatible(license))
1273 mod->gpl_compatible = 1;
1275 mod->gpl_compatible = 0;
1278 license = get_next_modinfo(info.modinfo, info.modinfo_len,
1279 "license", license);
1282 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1283 symname = info.strtab + sym->st_name;
1285 handle_modversions(mod, &info, sym, symname);
1286 handle_moddevtable(mod, &info, sym, symname);
1288 check_sec_ref(mod, modname, &info, init_section, init_section_ref_ok);
1289 check_sec_ref(mod, modname, &info, exit_section, exit_section_ref_ok);
1291 version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1293 maybe_frob_rcs_version(modname, version, info.modinfo,
1294 version - (char *)info.hdr);
1295 if (version || (all_versions && !is_vmlinux(modname)))
1296 get_src_version(modname, mod->srcversion,
1297 sizeof(mod->srcversion)-1);
1299 parse_elf_finish(&info);
1301 /* Our trick to get versioning for struct_module - it's
1302 * never passed as an argument to an exported function, so
1303 * the automatic versioning doesn't pick it up, but it's really
1304 * important anyhow */
1306 mod->unres = alloc_symbol("struct_module", 0, mod->unres);
1311 /* We first write the generated file into memory using the
1312 * following helper, then compare to the file on disk and
1313 * only update the later if anything changed */
1315 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
1316 const char *fmt, ...)
1323 len = vsnprintf(tmp, SZ, fmt, ap);
1324 buf_write(buf, tmp, len);
1328 void buf_write(struct buffer *buf, const char *s, int len)
1330 if (buf->size - buf->pos < len) {
1331 buf->size += len + SZ;
1332 buf->p = realloc(buf->p, buf->size);
1334 strncpy(buf->p + buf->pos, s, len);
1338 static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
1340 const char *e = is_vmlinux(m) ?"":".ko";
1344 fatal("modpost: GPL-incompatible module %s%s "
1345 "uses GPL-only symbol '%s'\n", m, e, s);
1347 case export_unused_gpl:
1348 fatal("modpost: GPL-incompatible module %s%s "
1349 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
1351 case export_gpl_future:
1352 warn("modpost: GPL-incompatible module %s%s "
1353 "uses future GPL-only symbol '%s'\n", m, e, s);
1357 case export_unknown:
1363 static void check_for_unused(enum export exp, const char* m, const char* s)
1365 const char *e = is_vmlinux(m) ?"":".ko";
1369 case export_unused_gpl:
1370 warn("modpost: module %s%s "
1371 "uses symbol '%s' marked UNUSED\n", m, e, s);
1379 static void check_exports(struct module *mod)
1381 struct symbol *s, *exp;
1383 for (s = mod->unres; s; s = s->next) {
1384 const char *basename;
1385 exp = find_symbol(s->name);
1386 if (!exp || exp->module == mod)
1388 basename = strrchr(mod->name, '/');
1392 basename = mod->name;
1393 if (!mod->gpl_compatible)
1394 check_for_gpl_usage(exp->export, basename, exp->name);
1395 check_for_unused(exp->export, basename, exp->name);
1400 * Header for the generated file
1402 static void add_header(struct buffer *b, struct module *mod)
1404 buf_printf(b, "#include <linux/module.h>\n");
1405 buf_printf(b, "#include <linux/vermagic.h>\n");
1406 buf_printf(b, "#include <linux/compiler.h>\n");
1407 buf_printf(b, "\n");
1408 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
1409 buf_printf(b, "\n");
1410 buf_printf(b, "struct module __this_module\n");
1411 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
1412 buf_printf(b, " .name = KBUILD_MODNAME,\n");
1414 buf_printf(b, " .init = init_module,\n");
1415 if (mod->has_cleanup)
1416 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
1417 " .exit = cleanup_module,\n"
1419 buf_printf(b, " .arch = MODULE_ARCH_INIT,\n");
1420 buf_printf(b, "};\n");
1424 * Record CRCs for unresolved symbols
1426 static int add_versions(struct buffer *b, struct module *mod)
1428 struct symbol *s, *exp;
1431 for (s = mod->unres; s; s = s->next) {
1432 exp = find_symbol(s->name);
1433 if (!exp || exp->module == mod) {
1434 if (have_vmlinux && !s->weak) {
1435 if (warn_unresolved) {
1436 warn("\"%s\" [%s.ko] undefined!\n",
1437 s->name, mod->name);
1439 merror("\"%s\" [%s.ko] undefined!\n",
1440 s->name, mod->name);
1446 s->module = exp->module;
1447 s->crc_valid = exp->crc_valid;
1454 buf_printf(b, "\n");
1455 buf_printf(b, "static const struct modversion_info ____versions[]\n");
1456 buf_printf(b, "__attribute_used__\n");
1457 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
1459 for (s = mod->unres; s; s = s->next) {
1463 if (!s->crc_valid) {
1464 warn("\"%s\" [%s.ko] has no CRC!\n",
1465 s->name, mod->name);
1468 buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name);
1471 buf_printf(b, "};\n");
1476 static void add_depends(struct buffer *b, struct module *mod,
1477 struct module *modules)
1483 for (m = modules; m; m = m->next) {
1484 m->seen = is_vmlinux(m->name);
1487 buf_printf(b, "\n");
1488 buf_printf(b, "static const char __module_depends[]\n");
1489 buf_printf(b, "__attribute_used__\n");
1490 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
1491 buf_printf(b, "\"depends=");
1492 for (s = mod->unres; s; s = s->next) {
1497 if (s->module->seen)
1500 s->module->seen = 1;
1501 if ((p = strrchr(s->module->name, '/')) != NULL)
1504 p = s->module->name;
1505 buf_printf(b, "%s%s", first ? "" : ",", p);
1508 buf_printf(b, "\";\n");
1511 static void add_srcversion(struct buffer *b, struct module *mod)
1513 if (mod->srcversion[0]) {
1514 buf_printf(b, "\n");
1515 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
1520 static void write_if_changed(struct buffer *b, const char *fname)
1526 file = fopen(fname, "r");
1530 if (fstat(fileno(file), &st) < 0)
1533 if (st.st_size != b->pos)
1536 tmp = NOFAIL(malloc(b->pos));
1537 if (fread(tmp, 1, b->pos, file) != b->pos)
1540 if (memcmp(tmp, b->p, b->pos) != 0)
1552 file = fopen(fname, "w");
1557 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
1564 /* parse Module.symvers file. line format:
1565 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
1567 static void read_dump(const char *fname, unsigned int kernel)
1569 unsigned long size, pos = 0;
1570 void *file = grab_file(fname, &size);
1574 /* No symbol versions, silently ignore */
1577 while ((line = get_next_line(&pos, file, size))) {
1578 char *symname, *modname, *d, *export, *end;
1583 if (!(symname = strchr(line, '\t')))
1586 if (!(modname = strchr(symname, '\t')))
1589 if ((export = strchr(modname, '\t')) != NULL)
1591 if (export && ((end = strchr(export, '\t')) != NULL))
1593 crc = strtoul(line, &d, 16);
1594 if (*symname == '\0' || *modname == '\0' || *d != '\0')
1597 if (!(mod = find_module(modname))) {
1598 if (is_vmlinux(modname)) {
1601 mod = new_module(NOFAIL(strdup(modname)));
1604 s = sym_add_exported(symname, mod, export_no(export));
1607 sym_update_crc(symname, mod, crc, export_no(export));
1611 fatal("parse error in symbol dump file\n");
1614 /* For normal builds always dump all symbols.
1615 * For external modules only dump symbols
1616 * that are not read from kernel Module.symvers.
1618 static int dump_sym(struct symbol *sym)
1620 if (!external_module)
1622 if (sym->vmlinux || sym->kernel)
1627 static void write_dump(const char *fname)
1629 struct buffer buf = { };
1630 struct symbol *symbol;
1633 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
1634 symbol = symbolhash[n];
1636 if (dump_sym(symbol))
1637 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
1638 symbol->crc, symbol->name,
1639 symbol->module->name,
1640 export_str(symbol->export));
1641 symbol = symbol->next;
1644 write_if_changed(&buf, fname);
1647 int main(int argc, char **argv)
1650 struct buffer buf = { };
1652 char *kernel_read = NULL, *module_read = NULL;
1653 char *dump_write = NULL;
1657 while ((opt = getopt(argc, argv, "i:I:mo:aw")) != -1) {
1660 kernel_read = optarg;
1663 module_read = optarg;
1664 external_module = 1;
1670 dump_write = optarg;
1676 warn_unresolved = 1;
1684 read_dump(kernel_read, 1);
1686 read_dump(module_read, 0);
1688 while (optind < argc) {
1689 read_symbols(argv[optind++]);
1692 for (mod = modules; mod; mod = mod->next) {
1700 for (mod = modules; mod; mod = mod->next) {
1706 add_header(&buf, mod);
1707 err |= add_versions(&buf, mod);
1708 add_depends(&buf, mod, modules);
1709 add_moddevtable(&buf, mod);
1710 add_srcversion(&buf, mod);
1712 sprintf(fname, "%s.mod.c", mod->name);
1713 write_if_changed(&buf, fname);
1717 write_dump(dump_write);