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 refereces from .text.head to .init.data
616 * Whitelist all refereces from .text.head to .init.text
619 * Some symbols belong to init section but still it is ok to reference
620 * these from non-init sections as these symbols don't have any memory
621 * allocated for them and symbol address and value are same. So even
622 * if init section is freed, its ok to reference those symbols.
623 * For ex. symbols marking the init section boundaries.
624 * This pattern is identified by
625 * refsymname = __init_begin, _sinittext, _einittext
628 * Logos used in drivers/video/logo reside in __initdata but the
629 * funtion that references them are EXPORT_SYMBOL() so cannot be
630 * marker __init. So we whitelist them here.
636 static int secref_whitelist(const char *modname, const char *tosec,
637 const char *fromsec, const char *atsym,
638 const char *refsymname)
642 const char *pat2sym[] = {
644 "_template", /* scsi uses *_template a lot */
645 "_sht", /* scsi also used *_sht to some extent */
653 const char *pat3refsym[] = {
660 /* Check for pattern 0 */
661 if ((strcmp(fromsec, ".text.init.refok") == 0) ||
662 (strcmp(fromsec, ".data.init.refok") == 0))
665 /* Check for pattern 1 */
666 if (strcmp(tosec, ".init.data") != 0)
668 if (strncmp(fromsec, ".data", strlen(".data")) != 0)
670 if (strncmp(atsym, "__param", strlen("__param")) != 0)
676 /* Check for pattern 2 */
677 if ((strcmp(tosec, ".init.text") != 0) &&
678 (strcmp(tosec, ".exit.text") != 0) &&
679 (strcmp(tosec, ".init.data") != 0))
681 if (strcmp(fromsec, ".data") != 0)
684 for (s = pat2sym; *s; s++)
685 if (strrcmp(atsym, *s) == 0)
690 /* Check for pattern 3 */
691 if ((strcmp(fromsec, ".text.head") == 0) &&
692 ((strcmp(tosec, ".init.data") == 0) ||
693 (strcmp(tosec, ".init.text") == 0)))
696 /* Check for pattern 4 */
697 for (s = pat3refsym; *s; s++)
698 if (strcmp(refsymname, *s) == 0)
701 /* Check for pattern 5 */
702 if ((strcmp(tosec, ".init.data") == 0) &&
703 (strncmp(fromsec, ".text", strlen(".text")) == 0) &&
704 (strncmp(refsymname, "logo_", strlen("logo_")) == 0))
711 * Find symbol based on relocation record info.
712 * In some cases the symbol supplied is a valid symbol so
713 * return refsym. If st_name != 0 we assume this is a valid symbol.
714 * In other cases the symbol needs to be looked up in the symbol table
715 * based on section and address.
717 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf_Addr addr,
722 if (relsym->st_name != 0)
724 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
725 if (sym->st_shndx != relsym->st_shndx)
727 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
729 if (sym->st_value == addr)
735 static inline int is_arm_mapping_symbol(const char *str)
737 return str[0] == '$' && strchr("atd", str[1])
738 && (str[2] == '\0' || str[2] == '.');
742 * If there's no name there, ignore it; likewise, ignore it if it's
743 * one of the magic symbols emitted used by current ARM tools.
745 * Otherwise if find_symbols_between() returns those symbols, they'll
746 * fail the whitelist tests and cause lots of false alarms ... fixable
747 * only by merging __exit and __init sections into __text, bloating
748 * the kernel (which is especially evil on embedded platforms).
750 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
752 const char *name = elf->strtab + sym->st_name;
754 if (!name || !strlen(name))
756 return !is_arm_mapping_symbol(name);
760 * Find symbols before or equal addr and after addr - in the section sec.
761 * If we find two symbols with equal offset prefer one with a valid name.
762 * The ELF format may have a better way to detect what type of symbol
763 * it is, but this works for now.
765 static void find_symbols_between(struct elf_info *elf, Elf_Addr addr,
767 Elf_Sym **before, Elf_Sym **after)
770 Elf_Ehdr *hdr = elf->hdr;
771 Elf_Addr beforediff = ~0;
772 Elf_Addr afterdiff = ~0;
773 const char *secstrings = (void *)hdr +
774 elf->sechdrs[hdr->e_shstrndx].sh_offset;
779 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
782 if (sym->st_shndx >= SHN_LORESERVE)
784 symsec = secstrings + elf->sechdrs[sym->st_shndx].sh_name;
785 if (strcmp(symsec, sec) != 0)
787 if (!is_valid_name(elf, sym))
789 if (sym->st_value <= addr) {
790 if ((addr - sym->st_value) < beforediff) {
791 beforediff = addr - sym->st_value;
794 else if ((addr - sym->st_value) == beforediff) {
800 if ((sym->st_value - addr) < afterdiff) {
801 afterdiff = sym->st_value - addr;
804 else if ((sym->st_value - addr) == afterdiff) {
812 * Print a warning about a section mismatch.
813 * Try to find symbols near it so user can find it.
814 * Check whitelist before warning - it may be a false positive.
816 static void warn_sec_mismatch(const char *modname, const char *fromsec,
817 struct elf_info *elf, Elf_Sym *sym, Elf_Rela r)
819 const char *refsymname = "";
820 Elf_Sym *before, *after;
822 Elf_Ehdr *hdr = elf->hdr;
823 Elf_Shdr *sechdrs = elf->sechdrs;
824 const char *secstrings = (void *)hdr +
825 sechdrs[hdr->e_shstrndx].sh_offset;
826 const char *secname = secstrings + sechdrs[sym->st_shndx].sh_name;
828 find_symbols_between(elf, r.r_offset, fromsec, &before, &after);
830 refsym = find_elf_symbol(elf, r.r_addend, sym);
831 if (refsym && strlen(elf->strtab + refsym->st_name))
832 refsymname = elf->strtab + refsym->st_name;
834 /* check whitelist - we may ignore it */
836 secref_whitelist(modname, secname, fromsec,
837 elf->strtab + before->st_name, refsymname))
840 if (before && after) {
841 warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s "
842 "(between '%s' and '%s')\n",
843 modname, fromsec, (unsigned long long)r.r_offset,
845 elf->strtab + before->st_name,
846 elf->strtab + after->st_name);
848 warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s "
850 modname, fromsec, (unsigned long long)r.r_offset,
852 elf->strtab + before->st_name);
854 warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s "
855 "before '%s' (at offset -0x%llx)\n",
856 modname, fromsec, (unsigned long long)r.r_offset,
858 elf->strtab + after->st_name);
860 warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s\n",
861 modname, fromsec, (unsigned long long)r.r_offset,
862 secname, refsymname);
866 static unsigned int *reloc_location(struct elf_info *elf,
867 int rsection, Elf_Rela *r)
869 Elf_Shdr *sechdrs = elf->sechdrs;
870 int section = sechdrs[rsection].sh_info;
872 return (void *)elf->hdr + sechdrs[section].sh_offset +
873 (r->r_offset - sechdrs[section].sh_addr);
876 static int addend_386_rel(struct elf_info *elf, int rsection, Elf_Rela *r)
878 unsigned int r_typ = ELF_R_TYPE(r->r_info);
879 unsigned int *location = reloc_location(elf, rsection, r);
883 r->r_addend = TO_NATIVE(*location);
886 r->r_addend = TO_NATIVE(*location) + 4;
887 /* For CONFIG_RELOCATABLE=y */
888 if (elf->hdr->e_type == ET_EXEC)
889 r->r_addend += r->r_offset;
895 static int addend_arm_rel(struct elf_info *elf, int rsection, Elf_Rela *r)
897 unsigned int r_typ = ELF_R_TYPE(r->r_info);
901 /* From ARM ABI: (S + A) | T */
902 r->r_addend = (int)(long)(elf->symtab_start + ELF_R_SYM(r->r_info));
905 /* From ARM ABI: ((S + A) | T) - P */
906 r->r_addend = (int)(long)(elf->hdr + elf->sechdrs[rsection].sh_offset +
907 (r->r_offset - elf->sechdrs[rsection].sh_addr));
915 static int addend_mips_rel(struct elf_info *elf, int rsection, Elf_Rela *r)
917 unsigned int r_typ = ELF_R_TYPE(r->r_info);
918 unsigned int *location = reloc_location(elf, rsection, r);
921 if (r_typ == R_MIPS_HI16)
922 return 1; /* skip this */
923 inst = TO_NATIVE(*location);
926 r->r_addend = inst & 0xffff;
929 r->r_addend = (inst & 0x03ffffff) << 2;
939 * A module includes a number of sections that are discarded
940 * either when loaded or when used as built-in.
941 * For loaded modules all functions marked __init and all data
942 * marked __initdata will be discarded when the module has been intialized.
943 * Likewise for modules used built-in the sections marked __exit
944 * are discarded because __exit marked function are supposed to be called
945 * only when a moduel is unloaded which never happes for built-in modules.
946 * The check_sec_ref() function traverses all relocation records
947 * to find all references to a section that reference a section that will
948 * be discarded and warns about it.
950 static void check_sec_ref(struct module *mod, const char *modname,
951 struct elf_info *elf,
952 int section(const char*),
953 int section_ref_ok(const char *))
957 Elf_Ehdr *hdr = elf->hdr;
958 Elf_Shdr *sechdrs = elf->sechdrs;
959 const char *secstrings = (void *)hdr +
960 sechdrs[hdr->e_shstrndx].sh_offset;
962 /* Walk through all sections */
963 for (i = 0; i < hdr->e_shnum; i++) {
964 const char *name = secstrings + sechdrs[i].sh_name;
968 /* We want to process only relocation sections and not .init */
969 if (sechdrs[i].sh_type == SHT_RELA) {
971 Elf_Rela *start = (void *)hdr + sechdrs[i].sh_offset;
972 Elf_Rela *stop = (void*)start + sechdrs[i].sh_size;
973 name += strlen(".rela");
974 if (section_ref_ok(name))
977 for (rela = start; rela < stop; rela++) {
978 r.r_offset = TO_NATIVE(rela->r_offset);
979 #if KERNEL_ELFCLASS == ELFCLASS64
980 if (hdr->e_machine == EM_MIPS) {
982 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
983 r_sym = TO_NATIVE(r_sym);
984 r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
985 r.r_info = ELF64_R_INFO(r_sym, r_typ);
987 r.r_info = TO_NATIVE(rela->r_info);
988 r_sym = ELF_R_SYM(r.r_info);
991 r.r_info = TO_NATIVE(rela->r_info);
992 r_sym = ELF_R_SYM(r.r_info);
994 r.r_addend = TO_NATIVE(rela->r_addend);
995 sym = elf->symtab_start + r_sym;
996 /* Skip special sections */
997 if (sym->st_shndx >= SHN_LORESERVE)
1000 secname = secstrings +
1001 sechdrs[sym->st_shndx].sh_name;
1002 if (section(secname))
1003 warn_sec_mismatch(modname, name,
1006 } else if (sechdrs[i].sh_type == SHT_REL) {
1008 Elf_Rel *start = (void *)hdr + sechdrs[i].sh_offset;
1009 Elf_Rel *stop = (void*)start + sechdrs[i].sh_size;
1010 name += strlen(".rel");
1011 if (section_ref_ok(name))
1014 for (rel = start; rel < stop; rel++) {
1015 r.r_offset = TO_NATIVE(rel->r_offset);
1016 #if KERNEL_ELFCLASS == ELFCLASS64
1017 if (hdr->e_machine == EM_MIPS) {
1019 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1020 r_sym = TO_NATIVE(r_sym);
1021 r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1022 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1024 r.r_info = TO_NATIVE(rel->r_info);
1025 r_sym = ELF_R_SYM(r.r_info);
1028 r.r_info = TO_NATIVE(rel->r_info);
1029 r_sym = ELF_R_SYM(r.r_info);
1032 switch (hdr->e_machine) {
1034 if (addend_386_rel(elf, i, &r))
1038 if(addend_arm_rel(elf, i, &r))
1042 if (addend_mips_rel(elf, i, &r))
1046 sym = elf->symtab_start + r_sym;
1047 /* Skip special sections */
1048 if (sym->st_shndx >= SHN_LORESERVE)
1051 secname = secstrings +
1052 sechdrs[sym->st_shndx].sh_name;
1053 if (section(secname))
1054 warn_sec_mismatch(modname, name,
1062 * Identify sections from which references to either a
1063 * .init or a .exit section is OK.
1065 * [OPD] Keith Ownes <kaos@sgi.com> commented:
1066 * For our future {in}sanity, add a comment that this is the ppc .opd
1067 * section, not the ia64 .opd section.
1068 * ia64 .opd should not point to discarded sections.
1069 * [.rodata] like for .init.text we ignore .rodata references -same reason
1071 static int initexit_section_ref_ok(const char *name)
1074 /* Absolute section names */
1075 const char *namelist1[] = {
1076 "__bug_table", /* used by powerpc for BUG() */
1079 ".cranges", /* used by sh64 */
1081 ".machvec", /* ia64 + powerpc uses these */
1083 ".opd", /* See comment [OPD] */
1084 ".parainstructions",
1086 ".plt", /* seen on ARCH=um build on x86_64. Harmless */
1091 /* Start of section names */
1092 const char *namelist2[] = {
1095 ".note", /* ignore ELF notes - may contain anything */
1096 ".got", /* powerpc - global offset table */
1097 ".toc", /* powerpc - table of contents */
1100 /* part of section name */
1101 const char *namelist3 [] = {
1102 ".unwind", /* Sample: IA_64.unwind.exit.text */
1106 for (s = namelist1; *s; s++)
1107 if (strcmp(*s, name) == 0)
1109 for (s = namelist2; *s; s++)
1110 if (strncmp(*s, name, strlen(*s)) == 0)
1112 for (s = namelist3; *s; s++)
1113 if (strstr(name, *s) != NULL)
1119 * Functions used only during module init is marked __init and is stored in
1120 * a .init.text section. Likewise data is marked __initdata and stored in
1121 * a .init.data section.
1122 * If this section is one of these sections return 1
1123 * See include/linux/init.h for the details
1125 static int init_section(const char *name)
1127 if (strcmp(name, ".init") == 0)
1129 if (strncmp(name, ".init.", strlen(".init.")) == 0)
1135 * Identify sections from which references to a .init section is OK.
1137 * Unfortunately references to read only data that referenced .init
1138 * sections had to be excluded. Almost all of these are false
1139 * positives, they are created by gcc. The downside of excluding rodata
1140 * is that there really are some user references from rodata to
1141 * init code, e.g. drivers/video/vgacon.c:
1143 * const struct consw vga_con = {
1144 * con_startup: vgacon_startup,
1146 * where vgacon_startup is __init. If you want to wade through the false
1147 * positives, take out the check for rodata.
1149 static int init_section_ref_ok(const char *name)
1152 /* Absolute section names */
1153 const char *namelist1[] = {
1154 "__ftr_fixup", /* powerpc cpu feature fixup */
1155 "__fw_ftr_fixup", /* powerpc firmware feature fixup */
1157 ".data.rel.ro", /* used by parisc64 */
1162 /* Start of section names */
1163 const char *namelist2[] = {
1170 if (initexit_section_ref_ok(name))
1173 for (s = namelist1; *s; s++)
1174 if (strcmp(*s, name) == 0)
1176 for (s = namelist2; *s; s++)
1177 if (strncmp(*s, name, strlen(*s)) == 0)
1180 /* If section name ends with ".init" we allow references
1181 * as is the case with .initcallN.init, .early_param.init, .taglist.init etc
1183 if (strrcmp(name, ".init") == 0)
1189 * Functions used only during module exit is marked __exit and is stored in
1190 * a .exit.text section. Likewise data is marked __exitdata and stored in
1191 * a .exit.data section.
1192 * If this section is one of these sections return 1
1193 * See include/linux/init.h for the details
1195 static int exit_section(const char *name)
1197 if (strcmp(name, ".exit.text") == 0)
1199 if (strcmp(name, ".exit.data") == 0)
1206 * Identify sections from which references to a .exit section is OK.
1208 static int exit_section_ref_ok(const char *name)
1211 /* Absolute section names */
1212 const char *namelist1[] = {
1220 if (initexit_section_ref_ok(name))
1223 for (s = namelist1; *s; s++)
1224 if (strcmp(*s, name) == 0)
1229 static void read_symbols(char *modname)
1231 const char *symname;
1235 struct elf_info info = { };
1238 if (!parse_elf(&info, modname))
1241 mod = new_module(modname);
1243 /* When there's no vmlinux, don't print warnings about
1244 * unresolved symbols (since there'll be too many ;) */
1245 if (is_vmlinux(modname)) {
1250 license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1252 if (license_is_gpl_compatible(license))
1253 mod->gpl_compatible = 1;
1255 mod->gpl_compatible = 0;
1258 license = get_next_modinfo(info.modinfo, info.modinfo_len,
1259 "license", license);
1262 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1263 symname = info.strtab + sym->st_name;
1265 handle_modversions(mod, &info, sym, symname);
1266 handle_moddevtable(mod, &info, sym, symname);
1268 check_sec_ref(mod, modname, &info, init_section, init_section_ref_ok);
1269 check_sec_ref(mod, modname, &info, exit_section, exit_section_ref_ok);
1271 version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1273 maybe_frob_rcs_version(modname, version, info.modinfo,
1274 version - (char *)info.hdr);
1275 if (version || (all_versions && !is_vmlinux(modname)))
1276 get_src_version(modname, mod->srcversion,
1277 sizeof(mod->srcversion)-1);
1279 parse_elf_finish(&info);
1281 /* Our trick to get versioning for struct_module - it's
1282 * never passed as an argument to an exported function, so
1283 * the automatic versioning doesn't pick it up, but it's really
1284 * important anyhow */
1286 mod->unres = alloc_symbol("struct_module", 0, mod->unres);
1291 /* We first write the generated file into memory using the
1292 * following helper, then compare to the file on disk and
1293 * only update the later if anything changed */
1295 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
1296 const char *fmt, ...)
1303 len = vsnprintf(tmp, SZ, fmt, ap);
1304 buf_write(buf, tmp, len);
1308 void buf_write(struct buffer *buf, const char *s, int len)
1310 if (buf->size - buf->pos < len) {
1311 buf->size += len + SZ;
1312 buf->p = realloc(buf->p, buf->size);
1314 strncpy(buf->p + buf->pos, s, len);
1318 static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
1320 const char *e = is_vmlinux(m) ?"":".ko";
1324 fatal("modpost: GPL-incompatible module %s%s "
1325 "uses GPL-only symbol '%s'\n", m, e, s);
1327 case export_unused_gpl:
1328 fatal("modpost: GPL-incompatible module %s%s "
1329 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
1331 case export_gpl_future:
1332 warn("modpost: GPL-incompatible module %s%s "
1333 "uses future GPL-only symbol '%s'\n", m, e, s);
1337 case export_unknown:
1343 static void check_for_unused(enum export exp, const char* m, const char* s)
1345 const char *e = is_vmlinux(m) ?"":".ko";
1349 case export_unused_gpl:
1350 warn("modpost: module %s%s "
1351 "uses symbol '%s' marked UNUSED\n", m, e, s);
1359 static void check_exports(struct module *mod)
1361 struct symbol *s, *exp;
1363 for (s = mod->unres; s; s = s->next) {
1364 const char *basename;
1365 exp = find_symbol(s->name);
1366 if (!exp || exp->module == mod)
1368 basename = strrchr(mod->name, '/');
1372 basename = mod->name;
1373 if (!mod->gpl_compatible)
1374 check_for_gpl_usage(exp->export, basename, exp->name);
1375 check_for_unused(exp->export, basename, exp->name);
1380 * Header for the generated file
1382 static void add_header(struct buffer *b, struct module *mod)
1384 buf_printf(b, "#include <linux/module.h>\n");
1385 buf_printf(b, "#include <linux/vermagic.h>\n");
1386 buf_printf(b, "#include <linux/compiler.h>\n");
1387 buf_printf(b, "\n");
1388 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
1389 buf_printf(b, "\n");
1390 buf_printf(b, "struct module __this_module\n");
1391 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
1392 buf_printf(b, " .name = KBUILD_MODNAME,\n");
1394 buf_printf(b, " .init = init_module,\n");
1395 if (mod->has_cleanup)
1396 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
1397 " .exit = cleanup_module,\n"
1399 buf_printf(b, " .arch = MODULE_ARCH_INIT,\n");
1400 buf_printf(b, "};\n");
1404 * Record CRCs for unresolved symbols
1406 static int add_versions(struct buffer *b, struct module *mod)
1408 struct symbol *s, *exp;
1411 for (s = mod->unres; s; s = s->next) {
1412 exp = find_symbol(s->name);
1413 if (!exp || exp->module == mod) {
1414 if (have_vmlinux && !s->weak) {
1415 if (warn_unresolved) {
1416 warn("\"%s\" [%s.ko] undefined!\n",
1417 s->name, mod->name);
1419 merror("\"%s\" [%s.ko] undefined!\n",
1420 s->name, mod->name);
1426 s->module = exp->module;
1427 s->crc_valid = exp->crc_valid;
1434 buf_printf(b, "\n");
1435 buf_printf(b, "static const struct modversion_info ____versions[]\n");
1436 buf_printf(b, "__attribute_used__\n");
1437 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
1439 for (s = mod->unres; s; s = s->next) {
1443 if (!s->crc_valid) {
1444 warn("\"%s\" [%s.ko] has no CRC!\n",
1445 s->name, mod->name);
1448 buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name);
1451 buf_printf(b, "};\n");
1456 static void add_depends(struct buffer *b, struct module *mod,
1457 struct module *modules)
1463 for (m = modules; m; m = m->next) {
1464 m->seen = is_vmlinux(m->name);
1467 buf_printf(b, "\n");
1468 buf_printf(b, "static const char __module_depends[]\n");
1469 buf_printf(b, "__attribute_used__\n");
1470 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
1471 buf_printf(b, "\"depends=");
1472 for (s = mod->unres; s; s = s->next) {
1477 if (s->module->seen)
1480 s->module->seen = 1;
1481 if ((p = strrchr(s->module->name, '/')) != NULL)
1484 p = s->module->name;
1485 buf_printf(b, "%s%s", first ? "" : ",", p);
1488 buf_printf(b, "\";\n");
1491 static void add_srcversion(struct buffer *b, struct module *mod)
1493 if (mod->srcversion[0]) {
1494 buf_printf(b, "\n");
1495 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
1500 static void write_if_changed(struct buffer *b, const char *fname)
1506 file = fopen(fname, "r");
1510 if (fstat(fileno(file), &st) < 0)
1513 if (st.st_size != b->pos)
1516 tmp = NOFAIL(malloc(b->pos));
1517 if (fread(tmp, 1, b->pos, file) != b->pos)
1520 if (memcmp(tmp, b->p, b->pos) != 0)
1532 file = fopen(fname, "w");
1537 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
1544 /* parse Module.symvers file. line format:
1545 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
1547 static void read_dump(const char *fname, unsigned int kernel)
1549 unsigned long size, pos = 0;
1550 void *file = grab_file(fname, &size);
1554 /* No symbol versions, silently ignore */
1557 while ((line = get_next_line(&pos, file, size))) {
1558 char *symname, *modname, *d, *export, *end;
1563 if (!(symname = strchr(line, '\t')))
1566 if (!(modname = strchr(symname, '\t')))
1569 if ((export = strchr(modname, '\t')) != NULL)
1571 if (export && ((end = strchr(export, '\t')) != NULL))
1573 crc = strtoul(line, &d, 16);
1574 if (*symname == '\0' || *modname == '\0' || *d != '\0')
1577 if (!(mod = find_module(modname))) {
1578 if (is_vmlinux(modname)) {
1581 mod = new_module(NOFAIL(strdup(modname)));
1584 s = sym_add_exported(symname, mod, export_no(export));
1587 sym_update_crc(symname, mod, crc, export_no(export));
1591 fatal("parse error in symbol dump file\n");
1594 /* For normal builds always dump all symbols.
1595 * For external modules only dump symbols
1596 * that are not read from kernel Module.symvers.
1598 static int dump_sym(struct symbol *sym)
1600 if (!external_module)
1602 if (sym->vmlinux || sym->kernel)
1607 static void write_dump(const char *fname)
1609 struct buffer buf = { };
1610 struct symbol *symbol;
1613 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
1614 symbol = symbolhash[n];
1616 if (dump_sym(symbol))
1617 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
1618 symbol->crc, symbol->name,
1619 symbol->module->name,
1620 export_str(symbol->export));
1621 symbol = symbol->next;
1624 write_if_changed(&buf, fname);
1627 int main(int argc, char **argv)
1630 struct buffer buf = { };
1632 char *kernel_read = NULL, *module_read = NULL;
1633 char *dump_write = NULL;
1637 while ((opt = getopt(argc, argv, "i:I:mo:aw")) != -1) {
1640 kernel_read = optarg;
1643 module_read = optarg;
1644 external_module = 1;
1650 dump_write = optarg;
1656 warn_unresolved = 1;
1664 read_dump(kernel_read, 1);
1666 read_dump(module_read, 0);
1668 while (optind < argc) {
1669 read_symbols(argv[optind++]);
1672 for (mod = modules; mod; mod = mod->next) {
1680 for (mod = modules; mod; mod = mod->next) {
1686 add_header(&buf, mod);
1687 err |= add_versions(&buf, mod);
1688 add_depends(&buf, mod, modules);
1689 add_moddevtable(&buf, mod);
1690 add_srcversion(&buf, mod);
1692 sprintf(fname, "%s.mod.c", mod->name);
1693 write_if_changed(&buf, fname);
1697 write_dump(dump_write);