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 sechdrs = (void *)hdr + hdr->e_shoff;
378 info->sechdrs = sechdrs;
380 /* Fix endianness in section headers */
381 for (i = 0; i < hdr->e_shnum; i++) {
382 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
383 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
384 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
385 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
386 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
387 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info);
389 /* Find symbol table. */
390 for (i = 1; i < hdr->e_shnum; i++) {
391 const char *secstrings
392 = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
395 if (sechdrs[i].sh_offset > info->size) {
396 fatal("%s is truncated. sechdrs[i].sh_offset=%u > sizeof(*hrd)=%ul\n", filename, (unsigned int)sechdrs[i].sh_offset, sizeof(*hdr));
399 secname = secstrings + sechdrs[i].sh_name;
400 if (strcmp(secname, ".modinfo") == 0) {
401 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
402 info->modinfo_len = sechdrs[i].sh_size;
403 } else if (strcmp(secname, "__ksymtab") == 0)
404 info->export_sec = i;
405 else if (strcmp(secname, "__ksymtab_unused") == 0)
406 info->export_unused_sec = i;
407 else if (strcmp(secname, "__ksymtab_gpl") == 0)
408 info->export_gpl_sec = i;
409 else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
410 info->export_unused_gpl_sec = i;
411 else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
412 info->export_gpl_future_sec = i;
414 if (sechdrs[i].sh_type != SHT_SYMTAB)
417 info->symtab_start = (void *)hdr + sechdrs[i].sh_offset;
418 info->symtab_stop = (void *)hdr + sechdrs[i].sh_offset
419 + sechdrs[i].sh_size;
420 info->strtab = (void *)hdr +
421 sechdrs[sechdrs[i].sh_link].sh_offset;
423 if (!info->symtab_start) {
424 fatal("%s has no symtab?\n", filename);
426 /* Fix endianness in symbols */
427 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
428 sym->st_shndx = TO_NATIVE(sym->st_shndx);
429 sym->st_name = TO_NATIVE(sym->st_name);
430 sym->st_value = TO_NATIVE(sym->st_value);
431 sym->st_size = TO_NATIVE(sym->st_size);
436 static void parse_elf_finish(struct elf_info *info)
438 release_file(info->hdr, info->size);
441 #define CRC_PFX MODULE_SYMBOL_PREFIX "__crc_"
442 #define KSYMTAB_PFX MODULE_SYMBOL_PREFIX "__ksymtab_"
444 static void handle_modversions(struct module *mod, struct elf_info *info,
445 Elf_Sym *sym, const char *symname)
448 enum export export = export_from_sec(info, sym->st_shndx);
450 switch (sym->st_shndx) {
452 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
456 if (memcmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
457 crc = (unsigned int) sym->st_value;
458 sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
463 /* undefined symbol */
464 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
465 ELF_ST_BIND(sym->st_info) != STB_WEAK)
467 /* ignore global offset table */
468 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
470 /* ignore __this_module, it will be resolved shortly */
471 if (strcmp(symname, MODULE_SYMBOL_PREFIX "__this_module") == 0)
473 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
474 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
475 /* add compatibility with older glibc */
476 #ifndef STT_SPARC_REGISTER
477 #define STT_SPARC_REGISTER STT_REGISTER
479 if (info->hdr->e_machine == EM_SPARC ||
480 info->hdr->e_machine == EM_SPARCV9) {
481 /* Ignore register directives. */
482 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
484 if (symname[0] == '.') {
485 char *munged = strdup(symname);
487 munged[1] = toupper(munged[1]);
493 if (memcmp(symname, MODULE_SYMBOL_PREFIX,
494 strlen(MODULE_SYMBOL_PREFIX)) == 0)
495 mod->unres = alloc_symbol(symname +
496 strlen(MODULE_SYMBOL_PREFIX),
497 ELF_ST_BIND(sym->st_info) == STB_WEAK,
501 /* All exported symbols */
502 if (memcmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
503 sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
506 if (strcmp(symname, MODULE_SYMBOL_PREFIX "init_module") == 0)
508 if (strcmp(symname, MODULE_SYMBOL_PREFIX "cleanup_module") == 0)
509 mod->has_cleanup = 1;
515 * Parse tag=value strings from .modinfo section
517 static char *next_string(char *string, unsigned long *secsize)
519 /* Skip non-zero chars */
522 if ((*secsize)-- <= 1)
526 /* Skip any zero padding. */
529 if ((*secsize)-- <= 1)
535 static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
536 const char *tag, char *info)
539 unsigned int taglen = strlen(tag);
540 unsigned long size = modinfo_len;
543 size -= info - (char *)modinfo;
544 modinfo = next_string(info, &size);
547 for (p = modinfo; p; p = next_string(p, &size)) {
548 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
549 return p + taglen + 1;
554 static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
558 return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
562 * Test if string s ends in string sub
565 static int strrcmp(const char *s, const char *sub)
573 sublen = strlen(sub);
575 if ((slen == 0) || (sublen == 0))
581 return memcmp(s + slen - sublen, sub, sublen);
585 * Whitelist to allow certain references to pass with no warning.
587 * If a module parameter is declared __initdata and permissions=0
588 * then this is legal despite the warning generated.
589 * We cannot see value of permissions here, so just ignore
591 * The pattern is identified by:
597 * Many drivers utilise a *driver container with references to
598 * add, remove, probe functions etc.
599 * These functions may often be marked __init and we do not want to
601 * the pattern is identified by:
602 * tosec = .init.text | .exit.text | .init.data
604 * atsym = *driver, *_template, *_sht, *_ops, *_probe, *probe_one, *_console
607 * Whitelist all references from .pci_fixup* section to .init.text
608 * This is part of the PCI init when built-in
611 * Whitelist all refereces from .text.head to .init.data
612 * Whitelist all refereces from .text.head to .init.text
615 * Some symbols belong to init section but still it is ok to reference
616 * these from non-init sections as these symbols don't have any memory
617 * allocated for them and symbol address and value are same. So even
618 * if init section is freed, its ok to reference those symbols.
619 * For ex. symbols marking the init section boundaries.
620 * This pattern is identified by
621 * refsymname = __init_begin, _sinittext, _einittext
624 * During the early init phase we have references from .init.text to
625 * .text we have an intended section mismatch - do not warn about it.
626 * See kernel_init() in init/main.c
629 * atsym = kernel_init
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 * Symbols contained in .paravirtprobe may safely reference .init.text.
644 * fromsec = .paravirtprobe
647 * Some of functions are common code between boot time and hotplug
648 * time. The bootmem allocater is called only boot time in its
649 * functions. So it's ok to reference.
653 * ia64 has machvec table for each platform. It is mixture of function
654 * pointer of .init.text and .text.
657 static int secref_whitelist(const char *modname, const char *tosec,
658 const char *fromsec, const char *atsym,
659 const char *refsymname)
663 const char *pat2sym[] = {
665 "_template", /* scsi uses *_template a lot */
666 "_sht", /* scsi also used *_sht to some extent */
675 const char *pat3refsym[] = {
682 const char *pat4sym[] = {
683 "sparse_index_alloc",
684 "zone_wait_table_init",
688 /* Check for pattern 1 */
689 if (strcmp(tosec, ".init.data") != 0)
691 if (strncmp(fromsec, ".data", strlen(".data")) != 0)
693 if (strncmp(atsym, "__param", strlen("__param")) != 0)
699 /* Check for pattern 2 */
700 if ((strcmp(tosec, ".init.text") != 0) &&
701 (strcmp(tosec, ".exit.text") != 0) &&
702 (strcmp(tosec, ".init.data") != 0))
704 if (strcmp(fromsec, ".data") != 0)
707 for (s = pat2sym; *s; s++)
708 if (strrcmp(atsym, *s) == 0)
713 /* Check for pattern 3 */
714 if ((strncmp(fromsec, ".pci_fixup", strlen(".pci_fixup")) == 0) &&
715 (strcmp(tosec, ".init.text") == 0))
718 /* Check for pattern 4 */
719 if ((strcmp(fromsec, ".text.head") == 0) &&
720 ((strcmp(tosec, ".init.data") == 0) ||
721 (strcmp(tosec, ".init.text") == 0)))
724 /* Check for pattern 5 */
725 for (s = pat3refsym; *s; s++)
726 if (strcmp(refsymname, *s) == 0)
729 /* Check for pattern 6 */
730 if ((strcmp(tosec, ".init.text") == 0) &&
731 (strcmp(fromsec, ".text") == 0) &&
732 (strcmp(refsymname, "kernel_init") == 0))
735 /* Check for pattern 7 */
736 if ((strcmp(tosec, ".init.data") == 0) &&
737 (strncmp(fromsec, ".text", strlen(".text")) == 0) &&
738 (strncmp(refsymname, "logo_", strlen("logo_")) == 0))
741 /* Check for pattern 8 */
742 if ((strcmp(tosec, ".init.text") == 0) &&
743 (strcmp(fromsec, ".paravirtprobe") == 0))
746 /* Check for pattern 9 */
747 if ((strcmp(tosec, ".init.text") == 0) &&
748 (strcmp(fromsec, ".text") == 0))
749 for (s = pat4sym; *s; s++)
750 if (strcmp(atsym, *s) == 0)
753 /* Check for pattern 10 */
754 if (strcmp(fromsec, ".machvec") == 0)
761 * Find symbol based on relocation record info.
762 * In some cases the symbol supplied is a valid symbol so
763 * return refsym. If st_name != 0 we assume this is a valid symbol.
764 * In other cases the symbol needs to be looked up in the symbol table
765 * based on section and address.
767 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf_Addr addr,
772 if (relsym->st_name != 0)
774 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
775 if (sym->st_shndx != relsym->st_shndx)
777 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
779 if (sym->st_value == addr)
785 static inline int is_arm_mapping_symbol(const char *str)
787 return str[0] == '$' && strchr("atd", str[1])
788 && (str[2] == '\0' || str[2] == '.');
792 * If there's no name there, ignore it; likewise, ignore it if it's
793 * one of the magic symbols emitted used by current ARM tools.
795 * Otherwise if find_symbols_between() returns those symbols, they'll
796 * fail the whitelist tests and cause lots of false alarms ... fixable
797 * only by merging __exit and __init sections into __text, bloating
798 * the kernel (which is especially evil on embedded platforms).
800 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
802 const char *name = elf->strtab + sym->st_name;
804 if (!name || !strlen(name))
806 return !is_arm_mapping_symbol(name);
810 * Find symbols before or equal addr and after addr - in the section sec.
811 * If we find two symbols with equal offset prefer one with a valid name.
812 * The ELF format may have a better way to detect what type of symbol
813 * it is, but this works for now.
815 static void find_symbols_between(struct elf_info *elf, Elf_Addr addr,
817 Elf_Sym **before, Elf_Sym **after)
820 Elf_Ehdr *hdr = elf->hdr;
821 Elf_Addr beforediff = ~0;
822 Elf_Addr afterdiff = ~0;
823 const char *secstrings = (void *)hdr +
824 elf->sechdrs[hdr->e_shstrndx].sh_offset;
829 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
832 if (sym->st_shndx >= SHN_LORESERVE)
834 symsec = secstrings + elf->sechdrs[sym->st_shndx].sh_name;
835 if (strcmp(symsec, sec) != 0)
837 if (!is_valid_name(elf, sym))
839 if (sym->st_value <= addr) {
840 if ((addr - sym->st_value) < beforediff) {
841 beforediff = addr - sym->st_value;
844 else if ((addr - sym->st_value) == beforediff) {
850 if ((sym->st_value - addr) < afterdiff) {
851 afterdiff = sym->st_value - addr;
854 else if ((sym->st_value - addr) == afterdiff) {
862 * Print a warning about a section mismatch.
863 * Try to find symbols near it so user can find it.
864 * Check whitelist before warning - it may be a false positive.
866 static void warn_sec_mismatch(const char *modname, const char *fromsec,
867 struct elf_info *elf, Elf_Sym *sym, Elf_Rela r)
869 const char *refsymname = "";
870 Elf_Sym *before, *after;
872 Elf_Ehdr *hdr = elf->hdr;
873 Elf_Shdr *sechdrs = elf->sechdrs;
874 const char *secstrings = (void *)hdr +
875 sechdrs[hdr->e_shstrndx].sh_offset;
876 const char *secname = secstrings + sechdrs[sym->st_shndx].sh_name;
878 find_symbols_between(elf, r.r_offset, fromsec, &before, &after);
880 refsym = find_elf_symbol(elf, r.r_addend, sym);
881 if (refsym && strlen(elf->strtab + refsym->st_name))
882 refsymname = elf->strtab + refsym->st_name;
884 /* check whitelist - we may ignore it */
886 secref_whitelist(modname, secname, fromsec,
887 elf->strtab + before->st_name, refsymname))
890 if (before && after) {
891 warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s "
892 "(between '%s' and '%s')\n",
893 modname, fromsec, (unsigned long long)r.r_offset,
895 elf->strtab + before->st_name,
896 elf->strtab + after->st_name);
898 warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s "
900 modname, fromsec, (unsigned long long)r.r_offset,
902 elf->strtab + before->st_name);
904 warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s "
905 "before '%s' (at offset -0x%llx)\n",
906 modname, fromsec, (unsigned long long)r.r_offset,
908 elf->strtab + after->st_name);
910 warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s\n",
911 modname, fromsec, (unsigned long long)r.r_offset,
912 secname, refsymname);
916 static void addend_386_rel(struct elf_info *elf, int section, Elf_Rela *r)
918 Elf_Shdr *sechdrs = elf->sechdrs;
920 unsigned int *location;
922 r_typ = ELF_R_TYPE(r->r_info);
923 location = (void *)elf->hdr +
924 sechdrs[sechdrs[section].sh_info].sh_offset + r->r_offset;
927 r->r_addend = TO_NATIVE(*location);
930 r->r_addend = TO_NATIVE(*location) + 4;
935 static void addend_arm_rel(struct elf_info *elf, int section, Elf_Rela *r)
937 Elf_Shdr *sechdrs = elf->sechdrs;
939 unsigned int *location;
941 r_typ = ELF_R_TYPE(r->r_info);
942 location = (void *)elf->hdr +
943 sechdrs[sechdrs[section].sh_info].sh_offset + r->r_offset;
946 r->r_addend = TO_NATIVE(*location);
949 r->r_addend = ((TO_NATIVE(*location) & 0x00ffffff) << 2) + 8;
954 static int addend_mips_rel(struct elf_info *elf, int section, Elf_Rela *r)
956 Elf_Shdr *sechdrs = elf->sechdrs;
958 unsigned int *location;
961 r_typ = ELF_R_TYPE(r->r_info);
962 if (r_typ == R_MIPS_HI16)
963 return 1; /* skip this */
964 location = (void *)elf->hdr +
965 sechdrs[sechdrs[section].sh_info].sh_offset + r->r_offset;
966 inst = TO_NATIVE(*location);
969 r->r_addend = ((inst & 0xffff) ^ 0x8000) - 0x8000;
972 r->r_addend = (inst & 0x03ffffff) << 2;
979 * A module includes a number of sections that are discarded
980 * either when loaded or when used as built-in.
981 * For loaded modules all functions marked __init and all data
982 * marked __initdata will be discarded when the module has been intialized.
983 * Likewise for modules used built-in the sections marked __exit
984 * are discarded because __exit marked function are supposed to be called
985 * only when a moduel is unloaded which never happes for built-in modules.
986 * The check_sec_ref() function traverses all relocation records
987 * to find all references to a section that reference a section that will
988 * be discarded and warns about it.
990 static void check_sec_ref(struct module *mod, const char *modname,
991 struct elf_info *elf,
992 int section(const char*),
993 int section_ref_ok(const char *))
997 Elf_Ehdr *hdr = elf->hdr;
998 Elf_Shdr *sechdrs = elf->sechdrs;
999 const char *secstrings = (void *)hdr +
1000 sechdrs[hdr->e_shstrndx].sh_offset;
1002 /* Walk through all sections */
1003 for (i = 0; i < hdr->e_shnum; i++) {
1004 const char *name = secstrings + sechdrs[i].sh_name;
1005 const char *secname;
1008 /* We want to process only relocation sections and not .init */
1009 if (sechdrs[i].sh_type == SHT_RELA) {
1011 Elf_Rela *start = (void *)hdr + sechdrs[i].sh_offset;
1012 Elf_Rela *stop = (void*)start + sechdrs[i].sh_size;
1013 name += strlen(".rela");
1014 if (section_ref_ok(name))
1017 for (rela = start; rela < stop; rela++) {
1018 r.r_offset = TO_NATIVE(rela->r_offset);
1019 #if KERNEL_ELFCLASS == ELFCLASS64
1020 if (hdr->e_machine == EM_MIPS) {
1022 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1023 r_sym = TO_NATIVE(r_sym);
1024 r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1025 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1027 r.r_info = TO_NATIVE(rela->r_info);
1028 r_sym = ELF_R_SYM(r.r_info);
1031 r.r_info = TO_NATIVE(rela->r_info);
1032 r_sym = ELF_R_SYM(r.r_info);
1034 r.r_addend = TO_NATIVE(rela->r_addend);
1035 sym = elf->symtab_start + r_sym;
1036 /* Skip special sections */
1037 if (sym->st_shndx >= SHN_LORESERVE)
1040 secname = secstrings +
1041 sechdrs[sym->st_shndx].sh_name;
1042 if (section(secname))
1043 warn_sec_mismatch(modname, name,
1046 } else if (sechdrs[i].sh_type == SHT_REL) {
1048 Elf_Rel *start = (void *)hdr + sechdrs[i].sh_offset;
1049 Elf_Rel *stop = (void*)start + sechdrs[i].sh_size;
1050 name += strlen(".rel");
1051 if (section_ref_ok(name))
1054 for (rel = start; rel < stop; rel++) {
1055 r.r_offset = TO_NATIVE(rel->r_offset);
1056 #if KERNEL_ELFCLASS == ELFCLASS64
1057 if (hdr->e_machine == EM_MIPS) {
1059 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1060 r_sym = TO_NATIVE(r_sym);
1061 r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1062 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1064 r.r_info = TO_NATIVE(rel->r_info);
1065 r_sym = ELF_R_SYM(r.r_info);
1068 r.r_info = TO_NATIVE(rel->r_info);
1069 r_sym = ELF_R_SYM(r.r_info);
1072 if (hdr->e_machine == EM_386)
1073 addend_386_rel(elf, i, &r);
1074 else if (hdr->e_machine == EM_ARM)
1075 addend_arm_rel(elf, i, &r);
1076 else if (hdr->e_machine == EM_MIPS) {
1077 if (addend_mips_rel(elf, i, &r))
1080 sym = elf->symtab_start + r_sym;
1081 /* Skip special sections */
1082 if (sym->st_shndx >= SHN_LORESERVE)
1085 secname = secstrings +
1086 sechdrs[sym->st_shndx].sh_name;
1087 if (section(secname))
1088 warn_sec_mismatch(modname, name,
1096 * Functions used only during module init is marked __init and is stored in
1097 * a .init.text section. Likewise data is marked __initdata and stored in
1098 * a .init.data section.
1099 * If this section is one of these sections return 1
1100 * See include/linux/init.h for the details
1102 static int init_section(const char *name)
1104 if (strcmp(name, ".init") == 0)
1106 if (strncmp(name, ".init.", strlen(".init.")) == 0)
1112 * Identify sections from which references to a .init section is OK.
1114 * Unfortunately references to read only data that referenced .init
1115 * sections had to be excluded. Almost all of these are false
1116 * positives, they are created by gcc. The downside of excluding rodata
1117 * is that there really are some user references from rodata to
1118 * init code, e.g. drivers/video/vgacon.c:
1120 * const struct consw vga_con = {
1121 * con_startup: vgacon_startup,
1123 * where vgacon_startup is __init. If you want to wade through the false
1124 * positives, take out the check for rodata.
1126 static int init_section_ref_ok(const char *name)
1129 /* Absolute section names */
1130 const char *namelist1[] = {
1132 ".opd", /* see comment [OPD] at exit_section_ref_ok() */
1133 ".toc1", /* used by ppc64 */
1135 ".data.rel.ro", /* used by parisc64 */
1136 ".parainstructions",
1138 "__bug_table", /* used by powerpc for BUG() */
1139 ".pci_fixup_header",
1146 ".plt", /* seen on ARCH=um build on x86_64. Harmless */
1147 "__ftr_fixup", /* powerpc cpu feature fixup */
1148 "__fw_ftr_fixup", /* powerpc firmware feature fixup */
1151 /* Start of section names */
1152 const char *namelist2[] = {
1157 ".parainstructions",
1161 /* part of section name */
1162 const char *namelist3 [] = {
1163 ".unwind", /* sample: IA_64.unwind.init.text */
1167 for (s = namelist1; *s; s++)
1168 if (strcmp(*s, name) == 0)
1170 for (s = namelist2; *s; s++)
1171 if (strncmp(*s, name, strlen(*s)) == 0)
1173 for (s = namelist3; *s; s++)
1174 if (strstr(name, *s) != NULL)
1176 if (strrcmp(name, ".init") == 0)
1182 * Functions used only during module exit is marked __exit and is stored in
1183 * a .exit.text section. Likewise data is marked __exitdata and stored in
1184 * a .exit.data section.
1185 * If this section is one of these sections return 1
1186 * See include/linux/init.h for the details
1188 static int exit_section(const char *name)
1190 if (strcmp(name, ".exit.text") == 0)
1192 if (strcmp(name, ".exit.data") == 0)
1199 * Identify sections from which references to a .exit section is OK.
1201 * [OPD] Keith Ownes <kaos@sgi.com> commented:
1202 * For our future {in}sanity, add a comment that this is the ppc .opd
1203 * section, not the ia64 .opd section.
1204 * ia64 .opd should not point to discarded sections.
1205 * [.rodata] like for .init.text we ignore .rodata references -same reason
1207 static int exit_section_ref_ok(const char *name)
1210 /* Absolute section names */
1211 const char *namelist1[] = {
1216 ".opd", /* See comment [OPD] */
1217 ".toc1", /* used by ppc64 */
1220 "__bug_table", /* used by powerpc for BUG() */
1223 ".parainstructions",
1228 ".plt", /* seen on ARCH=um build on x86_64. Harmless */
1231 /* Start of section names */
1232 const char *namelist2[] = {
1236 /* part of section name */
1237 const char *namelist3 [] = {
1238 ".unwind", /* Sample: IA_64.unwind.exit.text */
1242 for (s = namelist1; *s; s++)
1243 if (strcmp(*s, name) == 0)
1245 for (s = namelist2; *s; s++)
1246 if (strncmp(*s, name, strlen(*s)) == 0)
1248 for (s = namelist3; *s; s++)
1249 if (strstr(name, *s) != NULL)
1254 static void read_symbols(char *modname)
1256 const char *symname;
1260 struct elf_info info = { };
1263 if (!parse_elf(&info, modname))
1266 mod = new_module(modname);
1268 /* When there's no vmlinux, don't print warnings about
1269 * unresolved symbols (since there'll be too many ;) */
1270 if (is_vmlinux(modname)) {
1275 license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1277 if (license_is_gpl_compatible(license))
1278 mod->gpl_compatible = 1;
1280 mod->gpl_compatible = 0;
1283 license = get_next_modinfo(info.modinfo, info.modinfo_len,
1284 "license", license);
1287 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1288 symname = info.strtab + sym->st_name;
1290 handle_modversions(mod, &info, sym, symname);
1291 handle_moddevtable(mod, &info, sym, symname);
1293 check_sec_ref(mod, modname, &info, init_section, init_section_ref_ok);
1294 check_sec_ref(mod, modname, &info, exit_section, exit_section_ref_ok);
1296 version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1298 maybe_frob_rcs_version(modname, version, info.modinfo,
1299 version - (char *)info.hdr);
1300 if (version || (all_versions && !is_vmlinux(modname)))
1301 get_src_version(modname, mod->srcversion,
1302 sizeof(mod->srcversion)-1);
1304 parse_elf_finish(&info);
1306 /* Our trick to get versioning for struct_module - it's
1307 * never passed as an argument to an exported function, so
1308 * the automatic versioning doesn't pick it up, but it's really
1309 * important anyhow */
1311 mod->unres = alloc_symbol("struct_module", 0, mod->unres);
1316 /* We first write the generated file into memory using the
1317 * following helper, then compare to the file on disk and
1318 * only update the later if anything changed */
1320 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
1321 const char *fmt, ...)
1328 len = vsnprintf(tmp, SZ, fmt, ap);
1329 buf_write(buf, tmp, len);
1333 void buf_write(struct buffer *buf, const char *s, int len)
1335 if (buf->size - buf->pos < len) {
1336 buf->size += len + SZ;
1337 buf->p = realloc(buf->p, buf->size);
1339 strncpy(buf->p + buf->pos, s, len);
1343 static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
1345 const char *e = is_vmlinux(m) ?"":".ko";
1349 fatal("modpost: GPL-incompatible module %s%s "
1350 "uses GPL-only symbol '%s'\n", m, e, s);
1352 case export_unused_gpl:
1353 fatal("modpost: GPL-incompatible module %s%s "
1354 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
1356 case export_gpl_future:
1357 warn("modpost: GPL-incompatible module %s%s "
1358 "uses future GPL-only symbol '%s'\n", m, e, s);
1362 case export_unknown:
1368 static void check_for_unused(enum export exp, const char* m, const char* s)
1370 const char *e = is_vmlinux(m) ?"":".ko";
1374 case export_unused_gpl:
1375 warn("modpost: module %s%s "
1376 "uses symbol '%s' marked UNUSED\n", m, e, s);
1384 static void check_exports(struct module *mod)
1386 struct symbol *s, *exp;
1388 for (s = mod->unres; s; s = s->next) {
1389 const char *basename;
1390 exp = find_symbol(s->name);
1391 if (!exp || exp->module == mod)
1393 basename = strrchr(mod->name, '/');
1397 basename = mod->name;
1398 if (!mod->gpl_compatible)
1399 check_for_gpl_usage(exp->export, basename, exp->name);
1400 check_for_unused(exp->export, basename, exp->name);
1405 * Header for the generated file
1407 static void add_header(struct buffer *b, struct module *mod)
1409 buf_printf(b, "#include <linux/module.h>\n");
1410 buf_printf(b, "#include <linux/vermagic.h>\n");
1411 buf_printf(b, "#include <linux/compiler.h>\n");
1412 buf_printf(b, "\n");
1413 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
1414 buf_printf(b, "\n");
1415 buf_printf(b, "struct module __this_module\n");
1416 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
1417 buf_printf(b, " .name = KBUILD_MODNAME,\n");
1419 buf_printf(b, " .init = init_module,\n");
1420 if (mod->has_cleanup)
1421 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
1422 " .exit = cleanup_module,\n"
1424 buf_printf(b, " .arch = MODULE_ARCH_INIT,\n");
1425 buf_printf(b, "};\n");
1429 * Record CRCs for unresolved symbols
1431 static int add_versions(struct buffer *b, struct module *mod)
1433 struct symbol *s, *exp;
1436 for (s = mod->unres; s; s = s->next) {
1437 exp = find_symbol(s->name);
1438 if (!exp || exp->module == mod) {
1439 if (have_vmlinux && !s->weak) {
1440 if (warn_unresolved) {
1441 warn("\"%s\" [%s.ko] undefined!\n",
1442 s->name, mod->name);
1444 merror("\"%s\" [%s.ko] undefined!\n",
1445 s->name, mod->name);
1451 s->module = exp->module;
1452 s->crc_valid = exp->crc_valid;
1459 buf_printf(b, "\n");
1460 buf_printf(b, "static const struct modversion_info ____versions[]\n");
1461 buf_printf(b, "__attribute_used__\n");
1462 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
1464 for (s = mod->unres; s; s = s->next) {
1468 if (!s->crc_valid) {
1469 warn("\"%s\" [%s.ko] has no CRC!\n",
1470 s->name, mod->name);
1473 buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name);
1476 buf_printf(b, "};\n");
1481 static void add_depends(struct buffer *b, struct module *mod,
1482 struct module *modules)
1488 for (m = modules; m; m = m->next) {
1489 m->seen = is_vmlinux(m->name);
1492 buf_printf(b, "\n");
1493 buf_printf(b, "static const char __module_depends[]\n");
1494 buf_printf(b, "__attribute_used__\n");
1495 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
1496 buf_printf(b, "\"depends=");
1497 for (s = mod->unres; s; s = s->next) {
1502 if (s->module->seen)
1505 s->module->seen = 1;
1506 if ((p = strrchr(s->module->name, '/')) != NULL)
1509 p = s->module->name;
1510 buf_printf(b, "%s%s", first ? "" : ",", p);
1513 buf_printf(b, "\";\n");
1516 static void add_srcversion(struct buffer *b, struct module *mod)
1518 if (mod->srcversion[0]) {
1519 buf_printf(b, "\n");
1520 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
1525 static void write_if_changed(struct buffer *b, const char *fname)
1531 file = fopen(fname, "r");
1535 if (fstat(fileno(file), &st) < 0)
1538 if (st.st_size != b->pos)
1541 tmp = NOFAIL(malloc(b->pos));
1542 if (fread(tmp, 1, b->pos, file) != b->pos)
1545 if (memcmp(tmp, b->p, b->pos) != 0)
1557 file = fopen(fname, "w");
1562 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
1569 /* parse Module.symvers file. line format:
1570 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
1572 static void read_dump(const char *fname, unsigned int kernel)
1574 unsigned long size, pos = 0;
1575 void *file = grab_file(fname, &size);
1579 /* No symbol versions, silently ignore */
1582 while ((line = get_next_line(&pos, file, size))) {
1583 char *symname, *modname, *d, *export, *end;
1588 if (!(symname = strchr(line, '\t')))
1591 if (!(modname = strchr(symname, '\t')))
1594 if ((export = strchr(modname, '\t')) != NULL)
1596 if (export && ((end = strchr(export, '\t')) != NULL))
1598 crc = strtoul(line, &d, 16);
1599 if (*symname == '\0' || *modname == '\0' || *d != '\0')
1602 if (!(mod = find_module(modname))) {
1603 if (is_vmlinux(modname)) {
1606 mod = new_module(NOFAIL(strdup(modname)));
1609 s = sym_add_exported(symname, mod, export_no(export));
1612 sym_update_crc(symname, mod, crc, export_no(export));
1616 fatal("parse error in symbol dump file\n");
1619 /* For normal builds always dump all symbols.
1620 * For external modules only dump symbols
1621 * that are not read from kernel Module.symvers.
1623 static int dump_sym(struct symbol *sym)
1625 if (!external_module)
1627 if (sym->vmlinux || sym->kernel)
1632 static void write_dump(const char *fname)
1634 struct buffer buf = { };
1635 struct symbol *symbol;
1638 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
1639 symbol = symbolhash[n];
1641 if (dump_sym(symbol))
1642 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
1643 symbol->crc, symbol->name,
1644 symbol->module->name,
1645 export_str(symbol->export));
1646 symbol = symbol->next;
1649 write_if_changed(&buf, fname);
1652 int main(int argc, char **argv)
1655 struct buffer buf = { };
1657 char *kernel_read = NULL, *module_read = NULL;
1658 char *dump_write = NULL;
1662 while ((opt = getopt(argc, argv, "i:I:mo:aw")) != -1) {
1665 kernel_read = optarg;
1668 module_read = optarg;
1669 external_module = 1;
1675 dump_write = optarg;
1681 warn_unresolved = 1;
1689 read_dump(kernel_read, 1);
1691 read_dump(module_read, 0);
1693 while (optind < argc) {
1694 read_symbols(argv[optind++]);
1697 for (mod = modules; mod; mod = mod->next) {
1705 for (mod = modules; mod; mod = mod->next) {
1711 add_header(&buf, mod);
1712 err |= add_versions(&buf, mod);
1713 add_depends(&buf, mod, modules);
1714 add_moddevtable(&buf, mod);
1715 add_srcversion(&buf, mod);
1717 sprintf(fname, "%s.mod.c", mod->name);
1718 write_if_changed(&buf, fname);
1722 write_dump(dump_write);