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 static int is_vmlinux(const char *modname)
62 if ((myname = strrchr(modname, '/')))
67 return strcmp(myname, "vmlinux") == 0;
70 void *do_nofail(void *ptr, const char *expr)
73 fatal("modpost: Memory allocation failure: %s.\n", expr);
78 /* A list of all modules we processed */
80 static struct module *modules;
82 static struct module *find_module(char *modname)
86 for (mod = modules; mod; mod = mod->next)
87 if (strcmp(mod->name, modname) == 0)
92 static struct module *new_module(char *modname)
97 mod = NOFAIL(malloc(sizeof(*mod)));
98 memset(mod, 0, sizeof(*mod));
99 p = NOFAIL(strdup(modname));
101 /* strip trailing .o */
102 if ((s = strrchr(p, '.')) != NULL)
103 if (strcmp(s, ".o") == 0)
108 mod->gpl_compatible = -1;
115 /* A hash of all exported symbols,
116 * struct symbol is also used for lists of unresolved symbols */
118 #define SYMBOL_HASH_SIZE 1024
122 struct module *module;
126 unsigned int vmlinux:1; /* 1 if symbol is defined in vmlinux */
127 unsigned int kernel:1; /* 1 if symbol is from kernel
128 * (only for external modules) **/
129 unsigned int preloaded:1; /* 1 if symbol from Module.symvers */
130 enum export export; /* Type of export */
134 static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
136 /* This is based on the hash agorithm from gdbm, via tdb */
137 static inline unsigned int tdb_hash(const char *name)
139 unsigned value; /* Used to compute the hash value. */
140 unsigned i; /* Used to cycle through random values. */
142 /* Set the initial value from the key size. */
143 for (value = 0x238F13AF * strlen(name), i=0; name[i]; i++)
144 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
146 return (1103515243 * value + 12345);
150 * Allocate a new symbols for use in the hash of exported symbols or
151 * the list of unresolved symbols per module
153 static struct symbol *alloc_symbol(const char *name, unsigned int weak,
156 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
158 memset(s, 0, sizeof(*s));
159 strcpy(s->name, name);
165 /* For the hash of exported symbols */
166 static struct symbol *new_symbol(const char *name, struct module *module,
172 hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
173 new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
174 new->module = module;
175 new->export = export;
179 static struct symbol *find_symbol(const char *name)
183 /* For our purposes, .foo matches foo. PPC64 needs this. */
187 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s=s->next) {
188 if (strcmp(s->name, name) == 0)
198 { .str = "EXPORT_SYMBOL", .export = export_plain },
199 { .str = "EXPORT_UNUSED_SYMBOL", .export = export_unused },
200 { .str = "EXPORT_SYMBOL_GPL", .export = export_gpl },
201 { .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
202 { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
203 { .str = "(unknown)", .export = export_unknown },
207 static const char *export_str(enum export ex)
209 return export_list[ex].str;
212 static enum export export_no(const char * s)
216 return export_unknown;
217 for (i = 0; export_list[i].export != export_unknown; i++) {
218 if (strcmp(export_list[i].str, s) == 0)
219 return export_list[i].export;
221 return export_unknown;
224 static enum export export_from_sec(struct elf_info *elf, Elf_Section sec)
226 if (sec == elf->export_sec)
228 else if (sec == elf->export_unused_sec)
229 return export_unused;
230 else if (sec == elf->export_gpl_sec)
232 else if (sec == elf->export_unused_gpl_sec)
233 return export_unused_gpl;
234 else if (sec == elf->export_gpl_future_sec)
235 return export_gpl_future;
237 return export_unknown;
241 * Add an exported symbol - it may have already been added without a
242 * CRC, in this case just update the CRC
244 static struct symbol *sym_add_exported(const char *name, struct module *mod,
247 struct symbol *s = find_symbol(name);
250 s = new_symbol(name, mod, export);
253 warn("%s: '%s' exported twice. Previous export "
254 "was in %s%s\n", mod->name, name,
256 is_vmlinux(s->module->name) ?"":".ko");
260 s->vmlinux = is_vmlinux(mod->name);
266 static void sym_update_crc(const char *name, struct module *mod,
267 unsigned int crc, enum export export)
269 struct symbol *s = find_symbol(name);
272 s = new_symbol(name, mod, export);
277 void *grab_file(const char *filename, unsigned long *size)
283 fd = open(filename, O_RDONLY);
284 if (fd < 0 || fstat(fd, &st) != 0)
288 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
291 if (map == MAP_FAILED)
297 * Return a copy of the next line in a mmap'ed file.
298 * spaces in the beginning of the line is trimmed away.
299 * Return a pointer to a static buffer.
301 char* get_next_line(unsigned long *pos, void *file, unsigned long size)
303 static char line[4096];
306 signed char *p = (signed char *)file + *pos;
309 for (; *pos < size ; (*pos)++)
311 if (skip && isspace(*p)) {
316 if (*p != '\n' && (*pos < size)) {
320 break; /* Too long, stop */
331 void release_file(void *file, unsigned long size)
336 static int parse_elf(struct elf_info *info, const char *filename)
343 hdr = grab_file(filename, &info->size);
349 if (info->size < sizeof(*hdr)) {
350 /* file too small, assume this is an empty .o file */
353 /* Is this a valid ELF file? */
354 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
355 (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
356 (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
357 (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
358 /* Not an ELF file - silently ignore it */
361 /* Fix endianness in ELF header */
362 hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
363 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
364 hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
365 hdr->e_machine = TO_NATIVE(hdr->e_machine);
366 sechdrs = (void *)hdr + hdr->e_shoff;
367 info->sechdrs = sechdrs;
369 /* Fix endianness in section headers */
370 for (i = 0; i < hdr->e_shnum; i++) {
371 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
372 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
373 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
374 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
375 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
377 /* Find symbol table. */
378 for (i = 1; i < hdr->e_shnum; i++) {
379 const char *secstrings
380 = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
383 if (sechdrs[i].sh_offset > info->size) {
384 fatal("%s is truncated. sechdrs[i].sh_offset=%u > sizeof(*hrd)=%ul\n", filename, (unsigned int)sechdrs[i].sh_offset, sizeof(*hdr));
387 secname = secstrings + sechdrs[i].sh_name;
388 if (strcmp(secname, ".modinfo") == 0) {
389 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
390 info->modinfo_len = sechdrs[i].sh_size;
391 } else if (strcmp(secname, "__ksymtab") == 0)
392 info->export_sec = i;
393 else if (strcmp(secname, "__ksymtab_unused") == 0)
394 info->export_unused_sec = i;
395 else if (strcmp(secname, "__ksymtab_gpl") == 0)
396 info->export_gpl_sec = i;
397 else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
398 info->export_unused_gpl_sec = i;
399 else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
400 info->export_gpl_future_sec = i;
402 if (sechdrs[i].sh_type != SHT_SYMTAB)
405 info->symtab_start = (void *)hdr + sechdrs[i].sh_offset;
406 info->symtab_stop = (void *)hdr + sechdrs[i].sh_offset
407 + sechdrs[i].sh_size;
408 info->strtab = (void *)hdr +
409 sechdrs[sechdrs[i].sh_link].sh_offset;
411 if (!info->symtab_start) {
412 fatal("%s has no symtab?\n", filename);
414 /* Fix endianness in symbols */
415 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
416 sym->st_shndx = TO_NATIVE(sym->st_shndx);
417 sym->st_name = TO_NATIVE(sym->st_name);
418 sym->st_value = TO_NATIVE(sym->st_value);
419 sym->st_size = TO_NATIVE(sym->st_size);
424 static void parse_elf_finish(struct elf_info *info)
426 release_file(info->hdr, info->size);
429 #define CRC_PFX MODULE_SYMBOL_PREFIX "__crc_"
430 #define KSYMTAB_PFX MODULE_SYMBOL_PREFIX "__ksymtab_"
432 static void handle_modversions(struct module *mod, struct elf_info *info,
433 Elf_Sym *sym, const char *symname)
436 enum export export = export_from_sec(info, sym->st_shndx);
438 switch (sym->st_shndx) {
440 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
444 if (memcmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
445 crc = (unsigned int) sym->st_value;
446 sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
451 /* undefined symbol */
452 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
453 ELF_ST_BIND(sym->st_info) != STB_WEAK)
455 /* ignore global offset table */
456 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
458 /* ignore __this_module, it will be resolved shortly */
459 if (strcmp(symname, MODULE_SYMBOL_PREFIX "__this_module") == 0)
461 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
462 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
463 /* add compatibility with older glibc */
464 #ifndef STT_SPARC_REGISTER
465 #define STT_SPARC_REGISTER STT_REGISTER
467 if (info->hdr->e_machine == EM_SPARC ||
468 info->hdr->e_machine == EM_SPARCV9) {
469 /* Ignore register directives. */
470 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
472 if (symname[0] == '.') {
473 char *munged = strdup(symname);
475 munged[1] = toupper(munged[1]);
481 if (memcmp(symname, MODULE_SYMBOL_PREFIX,
482 strlen(MODULE_SYMBOL_PREFIX)) == 0)
483 mod->unres = alloc_symbol(symname +
484 strlen(MODULE_SYMBOL_PREFIX),
485 ELF_ST_BIND(sym->st_info) == STB_WEAK,
489 /* All exported symbols */
490 if (memcmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
491 sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
494 if (strcmp(symname, MODULE_SYMBOL_PREFIX "init_module") == 0)
496 if (strcmp(symname, MODULE_SYMBOL_PREFIX "cleanup_module") == 0)
497 mod->has_cleanup = 1;
503 * Parse tag=value strings from .modinfo section
505 static char *next_string(char *string, unsigned long *secsize)
507 /* Skip non-zero chars */
510 if ((*secsize)-- <= 1)
514 /* Skip any zero padding. */
517 if ((*secsize)-- <= 1)
523 static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
524 const char *tag, char *info)
527 unsigned int taglen = strlen(tag);
528 unsigned long size = modinfo_len;
531 size -= info - (char *)modinfo;
532 modinfo = next_string(info, &size);
535 for (p = modinfo; p; p = next_string(p, &size)) {
536 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
537 return p + taglen + 1;
542 static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
546 return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
550 * Test if string s ends in string sub
553 static int strrcmp(const char *s, const char *sub)
561 sublen = strlen(sub);
563 if ((slen == 0) || (sublen == 0))
569 return memcmp(s + slen - sublen, sub, sublen);
573 * Whitelist to allow certain references to pass with no warning.
575 * If a module parameter is declared __initdata and permissions=0
576 * then this is legal despite the warning generated.
577 * We cannot see value of permissions here, so just ignore
579 * The pattern is identified by:
585 * Many drivers utilise a *driver container with references to
586 * add, remove, probe functions etc.
587 * These functions may often be marked __init and we do not want to
589 * the pattern is identified by:
590 * tosec = .init.text | .exit.text | .init.data
592 * atsym = *driver, *_template, *_sht, *_ops, *_probe, *probe_one, *_console
595 * Whitelist all references from .pci_fixup* section to .init.text
596 * This is part of the PCI init when built-in
599 * Whitelist all refereces from .text.head to .init.data
600 * Whitelist all refereces from .text.head to .init.text
603 * Some symbols belong to init section but still it is ok to reference
604 * these from non-init sections as these symbols don't have any memory
605 * allocated for them and symbol address and value are same. So even
606 * if init section is freed, its ok to reference those symbols.
607 * For ex. symbols marking the init section boundaries.
608 * This pattern is identified by
609 * refsymname = __init_begin, _sinittext, _einittext
612 * During the early init phase we have references from .init.text to
613 * .text we have an intended section mismatch - do not warn about it.
614 * See kernel_init() in init/main.c
617 * atsym = kernel_init
618 * Some symbols belong to init section but still it is ok to reference
620 static int secref_whitelist(const char *modname, const char *tosec,
621 const char *fromsec, const char *atsym,
622 const char *refsymname)
626 const char *pat2sym[] = {
628 "_template", /* scsi uses *_template a lot */
629 "_sht", /* scsi also used *_sht to some extent */
637 const char *pat3refsym[] = {
644 /* Check for pattern 1 */
645 if (strcmp(tosec, ".init.data") != 0)
647 if (strncmp(fromsec, ".data", strlen(".data")) != 0)
649 if (strncmp(atsym, "__param", strlen("__param")) != 0)
655 /* Check for pattern 2 */
656 if ((strcmp(tosec, ".init.text") != 0) &&
657 (strcmp(tosec, ".exit.text") != 0) &&
658 (strcmp(tosec, ".init.data") != 0))
660 if (strcmp(fromsec, ".data") != 0)
663 for (s = pat2sym; *s; s++)
664 if (strrcmp(atsym, *s) == 0)
669 /* Check for pattern 3 */
670 if ((strncmp(fromsec, ".pci_fixup", strlen(".pci_fixup")) == 0) &&
671 (strcmp(tosec, ".init.text") == 0))
674 /* Check for pattern 4 */
675 if ((strcmp(fromsec, ".text.head") == 0) &&
676 ((strcmp(tosec, ".init.data") == 0) ||
677 (strcmp(tosec, ".init.text") == 0)))
680 /* Check for pattern 5 */
681 for (s = pat3refsym; *s; s++)
682 if (strcmp(refsymname, *s) == 0)
685 /* Check for pattern 6 */
686 if ((strcmp(tosec, ".init.text") == 0) &&
687 (strcmp(fromsec, ".text") == 0) &&
688 (strcmp(refsymname, "kernel_init") == 0))
694 * Find symbol based on relocation record info.
695 * In some cases the symbol supplied is a valid symbol so
696 * return refsym. If st_name != 0 we assume this is a valid symbol.
697 * In other cases the symbol needs to be looked up in the symbol table
698 * based on section and address.
700 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf_Addr addr,
705 if (relsym->st_name != 0)
707 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
708 if (sym->st_shndx != relsym->st_shndx)
710 if (sym->st_value == addr)
716 static inline int is_arm_mapping_symbol(const char *str)
718 return str[0] == '$' && strchr("atd", str[1])
719 && (str[2] == '\0' || str[2] == '.');
723 * If there's no name there, ignore it; likewise, ignore it if it's
724 * one of the magic symbols emitted used by current ARM tools.
726 * Otherwise if find_symbols_between() returns those symbols, they'll
727 * fail the whitelist tests and cause lots of false alarms ... fixable
728 * only by merging __exit and __init sections into __text, bloating
729 * the kernel (which is especially evil on embedded platforms).
731 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
733 const char *name = elf->strtab + sym->st_name;
735 if (!name || !strlen(name))
737 return !is_arm_mapping_symbol(name);
741 * Find symbols before or equal addr and after addr - in the section sec.
742 * If we find two symbols with equal offset prefer one with a valid name.
743 * The ELF format may have a better way to detect what type of symbol
744 * it is, but this works for now.
746 static void find_symbols_between(struct elf_info *elf, Elf_Addr addr,
748 Elf_Sym **before, Elf_Sym **after)
751 Elf_Ehdr *hdr = elf->hdr;
752 Elf_Addr beforediff = ~0;
753 Elf_Addr afterdiff = ~0;
754 const char *secstrings = (void *)hdr +
755 elf->sechdrs[hdr->e_shstrndx].sh_offset;
760 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
763 if (sym->st_shndx >= SHN_LORESERVE)
765 symsec = secstrings + elf->sechdrs[sym->st_shndx].sh_name;
766 if (strcmp(symsec, sec) != 0)
768 if (!is_valid_name(elf, sym))
770 if (sym->st_value <= addr) {
771 if ((addr - sym->st_value) < beforediff) {
772 beforediff = addr - sym->st_value;
775 else if ((addr - sym->st_value) == beforediff) {
781 if ((sym->st_value - addr) < afterdiff) {
782 afterdiff = sym->st_value - addr;
785 else if ((sym->st_value - addr) == afterdiff) {
793 * Print a warning about a section mismatch.
794 * Try to find symbols near it so user can find it.
795 * Check whitelist before warning - it may be a false positive.
797 static void warn_sec_mismatch(const char *modname, const char *fromsec,
798 struct elf_info *elf, Elf_Sym *sym, Elf_Rela r)
800 const char *refsymname = "";
801 Elf_Sym *before, *after;
803 Elf_Ehdr *hdr = elf->hdr;
804 Elf_Shdr *sechdrs = elf->sechdrs;
805 const char *secstrings = (void *)hdr +
806 sechdrs[hdr->e_shstrndx].sh_offset;
807 const char *secname = secstrings + sechdrs[sym->st_shndx].sh_name;
809 find_symbols_between(elf, r.r_offset, fromsec, &before, &after);
811 refsym = find_elf_symbol(elf, r.r_addend, sym);
812 if (refsym && strlen(elf->strtab + refsym->st_name))
813 refsymname = elf->strtab + refsym->st_name;
815 /* check whitelist - we may ignore it */
817 secref_whitelist(modname, secname, fromsec,
818 elf->strtab + before->st_name, refsymname))
821 if (before && after) {
822 warn("%s - Section mismatch: reference to %s:%s from %s "
823 "between '%s' (at offset 0x%llx) and '%s'\n",
824 modname, secname, refsymname, fromsec,
825 elf->strtab + before->st_name,
826 (long long)r.r_offset,
827 elf->strtab + after->st_name);
829 warn("%s - Section mismatch: reference to %s:%s from %s "
830 "after '%s' (at offset 0x%llx)\n",
831 modname, secname, refsymname, fromsec,
832 elf->strtab + before->st_name,
833 (long long)r.r_offset);
835 warn("%s - Section mismatch: reference to %s:%s from %s "
836 "before '%s' (at offset -0x%llx)\n",
837 modname, secname, refsymname, fromsec,
838 elf->strtab + after->st_name,
839 (long long)r.r_offset);
841 warn("%s - Section mismatch: reference to %s:%s from %s "
843 modname, secname, fromsec, refsymname,
844 (long long)r.r_offset);
849 * A module includes a number of sections that are discarded
850 * either when loaded or when used as built-in.
851 * For loaded modules all functions marked __init and all data
852 * marked __initdata will be discarded when the module has been intialized.
853 * Likewise for modules used built-in the sections marked __exit
854 * are discarded because __exit marked function are supposed to be called
855 * only when a moduel is unloaded which never happes for built-in modules.
856 * The check_sec_ref() function traverses all relocation records
857 * to find all references to a section that reference a section that will
858 * be discarded and warns about it.
860 static void check_sec_ref(struct module *mod, const char *modname,
861 struct elf_info *elf,
862 int section(const char*),
863 int section_ref_ok(const char *))
867 Elf_Ehdr *hdr = elf->hdr;
868 Elf_Shdr *sechdrs = elf->sechdrs;
869 const char *secstrings = (void *)hdr +
870 sechdrs[hdr->e_shstrndx].sh_offset;
872 /* Walk through all sections */
873 for (i = 0; i < hdr->e_shnum; i++) {
874 const char *name = secstrings + sechdrs[i].sh_name;
878 /* We want to process only relocation sections and not .init */
879 if (sechdrs[i].sh_type == SHT_RELA) {
881 Elf_Rela *start = (void *)hdr + sechdrs[i].sh_offset;
882 Elf_Rela *stop = (void*)start + sechdrs[i].sh_size;
883 name += strlen(".rela");
884 if (section_ref_ok(name))
887 for (rela = start; rela < stop; rela++) {
888 r.r_offset = TO_NATIVE(rela->r_offset);
889 #if KERNEL_ELFCLASS == ELFCLASS64
890 if (hdr->e_machine == EM_MIPS) {
891 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
892 r_sym = TO_NATIVE(r_sym);
894 r.r_info = TO_NATIVE(rela->r_info);
895 r_sym = ELF_R_SYM(r.r_info);
898 r.r_info = TO_NATIVE(rela->r_info);
899 r_sym = ELF_R_SYM(r.r_info);
901 r.r_addend = TO_NATIVE(rela->r_addend);
902 sym = elf->symtab_start + r_sym;
903 /* Skip special sections */
904 if (sym->st_shndx >= SHN_LORESERVE)
907 secname = secstrings +
908 sechdrs[sym->st_shndx].sh_name;
909 if (section(secname))
910 warn_sec_mismatch(modname, name,
913 } else if (sechdrs[i].sh_type == SHT_REL) {
915 Elf_Rel *start = (void *)hdr + sechdrs[i].sh_offset;
916 Elf_Rel *stop = (void*)start + sechdrs[i].sh_size;
917 name += strlen(".rel");
918 if (section_ref_ok(name))
921 for (rel = start; rel < stop; rel++) {
922 r.r_offset = TO_NATIVE(rel->r_offset);
923 #if KERNEL_ELFCLASS == ELFCLASS64
924 if (hdr->e_machine == EM_MIPS) {
925 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
926 r_sym = TO_NATIVE(r_sym);
928 r.r_info = TO_NATIVE(rel->r_info);
929 r_sym = ELF_R_SYM(r.r_info);
932 r.r_info = TO_NATIVE(rel->r_info);
933 r_sym = ELF_R_SYM(r.r_info);
936 sym = elf->symtab_start + r_sym;
937 /* Skip special sections */
938 if (sym->st_shndx >= SHN_LORESERVE)
941 secname = secstrings +
942 sechdrs[sym->st_shndx].sh_name;
943 if (section(secname))
944 warn_sec_mismatch(modname, name,
952 * Functions used only during module init is marked __init and is stored in
953 * a .init.text section. Likewise data is marked __initdata and stored in
954 * a .init.data section.
955 * If this section is one of these sections return 1
956 * See include/linux/init.h for the details
958 static int init_section(const char *name)
960 if (strcmp(name, ".init") == 0)
962 if (strncmp(name, ".init.", strlen(".init.")) == 0)
968 * Identify sections from which references to a .init section is OK.
970 * Unfortunately references to read only data that referenced .init
971 * sections had to be excluded. Almost all of these are false
972 * positives, they are created by gcc. The downside of excluding rodata
973 * is that there really are some user references from rodata to
974 * init code, e.g. drivers/video/vgacon.c:
976 * const struct consw vga_con = {
977 * con_startup: vgacon_startup,
979 * where vgacon_startup is __init. If you want to wade through the false
980 * positives, take out the check for rodata.
982 static int init_section_ref_ok(const char *name)
985 /* Absolute section names */
986 const char *namelist1[] = {
988 ".opd", /* see comment [OPD] at exit_section_ref_ok() */
989 ".toc1", /* used by ppc64 */
991 ".data.rel.ro", /* used by parisc64 */
994 "__bug_table", /* used by powerpc for BUG() */
1002 ".plt", /* seen on ARCH=um build on x86_64. Harmless */
1003 "__ftr_fixup", /* powerpc cpu feature fixup */
1004 "__fw_ftr_fixup", /* powerpc firmware feature fixup */
1007 /* Start of section names */
1008 const char *namelist2[] = {
1013 ".parainstructions",
1017 /* part of section name */
1018 const char *namelist3 [] = {
1019 ".unwind", /* sample: IA_64.unwind.init.text */
1023 for (s = namelist1; *s; s++)
1024 if (strcmp(*s, name) == 0)
1026 for (s = namelist2; *s; s++)
1027 if (strncmp(*s, name, strlen(*s)) == 0)
1029 for (s = namelist3; *s; s++)
1030 if (strstr(name, *s) != NULL)
1032 if (strrcmp(name, ".init") == 0)
1038 * Functions used only during module exit is marked __exit and is stored in
1039 * a .exit.text section. Likewise data is marked __exitdata and stored in
1040 * a .exit.data section.
1041 * If this section is one of these sections return 1
1042 * See include/linux/init.h for the details
1044 static int exit_section(const char *name)
1046 if (strcmp(name, ".exit.text") == 0)
1048 if (strcmp(name, ".exit.data") == 0)
1055 * Identify sections from which references to a .exit section is OK.
1057 * [OPD] Keith Ownes <kaos@sgi.com> commented:
1058 * For our future {in}sanity, add a comment that this is the ppc .opd
1059 * section, not the ia64 .opd section.
1060 * ia64 .opd should not point to discarded sections.
1061 * [.rodata] like for .init.text we ignore .rodata references -same reason
1063 static int exit_section_ref_ok(const char *name)
1066 /* Absolute section names */
1067 const char *namelist1[] = {
1072 ".opd", /* See comment [OPD] */
1073 ".toc1", /* used by ppc64 */
1076 "__bug_table", /* used by powerpc for BUG() */
1079 ".parainstructions",
1084 ".plt", /* seen on ARCH=um build on x86_64. Harmless */
1087 /* Start of section names */
1088 const char *namelist2[] = {
1092 /* part of section name */
1093 const char *namelist3 [] = {
1094 ".unwind", /* Sample: IA_64.unwind.exit.text */
1098 for (s = namelist1; *s; s++)
1099 if (strcmp(*s, name) == 0)
1101 for (s = namelist2; *s; s++)
1102 if (strncmp(*s, name, strlen(*s)) == 0)
1104 for (s = namelist3; *s; s++)
1105 if (strstr(name, *s) != NULL)
1110 static void read_symbols(char *modname)
1112 const char *symname;
1116 struct elf_info info = { };
1119 if (!parse_elf(&info, modname))
1122 mod = new_module(modname);
1124 /* When there's no vmlinux, don't print warnings about
1125 * unresolved symbols (since there'll be too many ;) */
1126 if (is_vmlinux(modname)) {
1131 license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1133 if (license_is_gpl_compatible(license))
1134 mod->gpl_compatible = 1;
1136 mod->gpl_compatible = 0;
1139 license = get_next_modinfo(info.modinfo, info.modinfo_len,
1140 "license", license);
1143 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1144 symname = info.strtab + sym->st_name;
1146 handle_modversions(mod, &info, sym, symname);
1147 handle_moddevtable(mod, &info, sym, symname);
1149 check_sec_ref(mod, modname, &info, init_section, init_section_ref_ok);
1150 check_sec_ref(mod, modname, &info, exit_section, exit_section_ref_ok);
1152 version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1154 maybe_frob_rcs_version(modname, version, info.modinfo,
1155 version - (char *)info.hdr);
1156 if (version || (all_versions && !is_vmlinux(modname)))
1157 get_src_version(modname, mod->srcversion,
1158 sizeof(mod->srcversion)-1);
1160 parse_elf_finish(&info);
1162 /* Our trick to get versioning for struct_module - it's
1163 * never passed as an argument to an exported function, so
1164 * the automatic versioning doesn't pick it up, but it's really
1165 * important anyhow */
1167 mod->unres = alloc_symbol("struct_module", 0, mod->unres);
1172 /* We first write the generated file into memory using the
1173 * following helper, then compare to the file on disk and
1174 * only update the later if anything changed */
1176 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
1177 const char *fmt, ...)
1184 len = vsnprintf(tmp, SZ, fmt, ap);
1185 buf_write(buf, tmp, len);
1189 void buf_write(struct buffer *buf, const char *s, int len)
1191 if (buf->size - buf->pos < len) {
1192 buf->size += len + SZ;
1193 buf->p = realloc(buf->p, buf->size);
1195 strncpy(buf->p + buf->pos, s, len);
1199 static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
1201 const char *e = is_vmlinux(m) ?"":".ko";
1205 fatal("modpost: GPL-incompatible module %s%s "
1206 "uses GPL-only symbol '%s'\n", m, e, s);
1208 case export_unused_gpl:
1209 fatal("modpost: GPL-incompatible module %s%s "
1210 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
1212 case export_gpl_future:
1213 warn("modpost: GPL-incompatible module %s%s "
1214 "uses future GPL-only symbol '%s'\n", m, e, s);
1218 case export_unknown:
1224 static void check_for_unused(enum export exp, const char* m, const char* s)
1226 const char *e = is_vmlinux(m) ?"":".ko";
1230 case export_unused_gpl:
1231 warn("modpost: module %s%s "
1232 "uses symbol '%s' marked UNUSED\n", m, e, s);
1240 static void check_exports(struct module *mod)
1242 struct symbol *s, *exp;
1244 for (s = mod->unres; s; s = s->next) {
1245 const char *basename;
1246 exp = find_symbol(s->name);
1247 if (!exp || exp->module == mod)
1249 basename = strrchr(mod->name, '/');
1253 basename = mod->name;
1254 if (!mod->gpl_compatible)
1255 check_for_gpl_usage(exp->export, basename, exp->name);
1256 check_for_unused(exp->export, basename, exp->name);
1261 * Header for the generated file
1263 static void add_header(struct buffer *b, struct module *mod)
1265 buf_printf(b, "#include <linux/module.h>\n");
1266 buf_printf(b, "#include <linux/vermagic.h>\n");
1267 buf_printf(b, "#include <linux/compiler.h>\n");
1268 buf_printf(b, "\n");
1269 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
1270 buf_printf(b, "\n");
1271 buf_printf(b, "struct module __this_module\n");
1272 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
1273 buf_printf(b, " .name = KBUILD_MODNAME,\n");
1275 buf_printf(b, " .init = init_module,\n");
1276 if (mod->has_cleanup)
1277 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
1278 " .exit = cleanup_module,\n"
1280 buf_printf(b, "};\n");
1284 * Record CRCs for unresolved symbols
1286 static int add_versions(struct buffer *b, struct module *mod)
1288 struct symbol *s, *exp;
1291 for (s = mod->unres; s; s = s->next) {
1292 exp = find_symbol(s->name);
1293 if (!exp || exp->module == mod) {
1294 if (have_vmlinux && !s->weak) {
1295 warn("\"%s\" [%s.ko] undefined!\n",
1296 s->name, mod->name);
1297 err = warn_unresolved ? 0 : 1;
1301 s->module = exp->module;
1302 s->crc_valid = exp->crc_valid;
1309 buf_printf(b, "\n");
1310 buf_printf(b, "static const struct modversion_info ____versions[]\n");
1311 buf_printf(b, "__attribute_used__\n");
1312 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
1314 for (s = mod->unres; s; s = s->next) {
1318 if (!s->crc_valid) {
1319 warn("\"%s\" [%s.ko] has no CRC!\n",
1320 s->name, mod->name);
1323 buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name);
1326 buf_printf(b, "};\n");
1331 static void add_depends(struct buffer *b, struct module *mod,
1332 struct module *modules)
1338 for (m = modules; m; m = m->next) {
1339 m->seen = is_vmlinux(m->name);
1342 buf_printf(b, "\n");
1343 buf_printf(b, "static const char __module_depends[]\n");
1344 buf_printf(b, "__attribute_used__\n");
1345 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
1346 buf_printf(b, "\"depends=");
1347 for (s = mod->unres; s; s = s->next) {
1352 if (s->module->seen)
1355 s->module->seen = 1;
1356 if ((p = strrchr(s->module->name, '/')) != NULL)
1359 p = s->module->name;
1360 buf_printf(b, "%s%s", first ? "" : ",", p);
1363 buf_printf(b, "\";\n");
1366 static void add_srcversion(struct buffer *b, struct module *mod)
1368 if (mod->srcversion[0]) {
1369 buf_printf(b, "\n");
1370 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
1375 static void write_if_changed(struct buffer *b, const char *fname)
1381 file = fopen(fname, "r");
1385 if (fstat(fileno(file), &st) < 0)
1388 if (st.st_size != b->pos)
1391 tmp = NOFAIL(malloc(b->pos));
1392 if (fread(tmp, 1, b->pos, file) != b->pos)
1395 if (memcmp(tmp, b->p, b->pos) != 0)
1407 file = fopen(fname, "w");
1412 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
1419 /* parse Module.symvers file. line format:
1420 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
1422 static void read_dump(const char *fname, unsigned int kernel)
1424 unsigned long size, pos = 0;
1425 void *file = grab_file(fname, &size);
1429 /* No symbol versions, silently ignore */
1432 while ((line = get_next_line(&pos, file, size))) {
1433 char *symname, *modname, *d, *export, *end;
1438 if (!(symname = strchr(line, '\t')))
1441 if (!(modname = strchr(symname, '\t')))
1444 if ((export = strchr(modname, '\t')) != NULL)
1446 if (export && ((end = strchr(export, '\t')) != NULL))
1448 crc = strtoul(line, &d, 16);
1449 if (*symname == '\0' || *modname == '\0' || *d != '\0')
1452 if (!(mod = find_module(modname))) {
1453 if (is_vmlinux(modname)) {
1456 mod = new_module(NOFAIL(strdup(modname)));
1459 s = sym_add_exported(symname, mod, export_no(export));
1462 sym_update_crc(symname, mod, crc, export_no(export));
1466 fatal("parse error in symbol dump file\n");
1469 /* For normal builds always dump all symbols.
1470 * For external modules only dump symbols
1471 * that are not read from kernel Module.symvers.
1473 static int dump_sym(struct symbol *sym)
1475 if (!external_module)
1477 if (sym->vmlinux || sym->kernel)
1482 static void write_dump(const char *fname)
1484 struct buffer buf = { };
1485 struct symbol *symbol;
1488 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
1489 symbol = symbolhash[n];
1491 if (dump_sym(symbol))
1492 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
1493 symbol->crc, symbol->name,
1494 symbol->module->name,
1495 export_str(symbol->export));
1496 symbol = symbol->next;
1499 write_if_changed(&buf, fname);
1502 int main(int argc, char **argv)
1505 struct buffer buf = { };
1507 char *kernel_read = NULL, *module_read = NULL;
1508 char *dump_write = NULL;
1512 while ((opt = getopt(argc, argv, "i:I:mo:aw")) != -1) {
1515 kernel_read = optarg;
1518 module_read = optarg;
1519 external_module = 1;
1525 dump_write = optarg;
1531 warn_unresolved = 1;
1539 read_dump(kernel_read, 1);
1541 read_dump(module_read, 0);
1543 while (optind < argc) {
1544 read_symbols(argv[optind++]);
1547 for (mod = modules; mod; mod = mod->next) {
1555 for (mod = modules; mod; mod = mod->next) {
1561 add_header(&buf, mod);
1562 err |= add_versions(&buf, mod);
1563 add_depends(&buf, mod, modules);
1564 add_moddevtable(&buf, mod);
1565 add_srcversion(&buf, mod);
1567 sprintf(fname, "%s.mod.c", mod->name);
1568 write_if_changed(&buf, fname);
1572 write_dump(dump_write);