1 /* Postprocess module symbol versions
3 * Copyright 2003 Kai Germaschewski
4 * Copyright 2002-2004 Rusty Russell, IBM Corporation
5 * Copyright 2006-2008 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 ...
22 #include "../../include/generated/autoconf.h"
23 #include "../../include/linux/license.h"
24 #include "../../include/linux/export.h"
26 /* Are we using CONFIG_MODVERSIONS? */
27 static int modversions = 0;
28 /* Warn about undefined symbols? (do so if we have vmlinux) */
29 static int have_vmlinux = 0;
30 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */
31 static int all_versions = 0;
32 /* If we are modposting external module set to 1 */
33 static int external_module = 0;
34 /* Warn about section mismatch in vmlinux if set to 1 */
35 static int vmlinux_section_warnings = 1;
36 /* Only warn about unresolved symbols */
37 static int warn_unresolved = 0;
38 /* How a symbol is exported */
39 static int sec_mismatch_count = 0;
40 static int sec_mismatch_verbose = 1;
41 static int sec_mismatch_fatal = 0;
42 /* ignore missing files */
43 static int ignore_missing_files;
46 export_plain, export_unused, export_gpl,
47 export_unused_gpl, export_gpl_future, export_unknown
50 #define PRINTF __attribute__ ((format (printf, 1, 2)))
52 PRINTF void fatal(const char *fmt, ...)
56 fprintf(stderr, "FATAL: ");
58 va_start(arglist, fmt);
59 vfprintf(stderr, fmt, arglist);
65 PRINTF void warn(const char *fmt, ...)
69 fprintf(stderr, "WARNING: ");
71 va_start(arglist, fmt);
72 vfprintf(stderr, fmt, arglist);
76 PRINTF void merror(const char *fmt, ...)
80 fprintf(stderr, "ERROR: ");
82 va_start(arglist, fmt);
83 vfprintf(stderr, fmt, arglist);
87 static inline bool strends(const char *str, const char *postfix)
89 if (strlen(str) < strlen(postfix))
92 return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0;
95 static int is_vmlinux(const char *modname)
99 myname = strrchr(modname, '/');
105 return (strcmp(myname, "vmlinux") == 0) ||
106 (strcmp(myname, "vmlinux.o") == 0);
109 void *do_nofail(void *ptr, const char *expr)
112 fatal("modpost: Memory allocation failure: %s.\n", expr);
117 /* A list of all modules we processed */
118 static struct module *modules;
120 static struct module *find_module(char *modname)
124 for (mod = modules; mod; mod = mod->next)
125 if (strcmp(mod->name, modname) == 0)
130 static struct module *new_module(const char *modname)
135 mod = NOFAIL(malloc(sizeof(*mod)));
136 memset(mod, 0, sizeof(*mod));
137 p = NOFAIL(strdup(modname));
139 /* strip trailing .o */
140 if (strends(p, ".o")) {
141 p[strlen(p) - 2] = '\0';
147 mod->gpl_compatible = -1;
154 /* A hash of all exported symbols,
155 * struct symbol is also used for lists of unresolved symbols */
157 #define SYMBOL_HASH_SIZE 1024
161 struct module *module;
165 unsigned int vmlinux:1; /* 1 if symbol is defined in vmlinux */
166 unsigned int kernel:1; /* 1 if symbol is from kernel
167 * (only for external modules) **/
168 unsigned int preloaded:1; /* 1 if symbol from Module.symvers, or crc */
169 enum export export; /* Type of export */
173 static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
175 /* This is based on the hash agorithm from gdbm, via tdb */
176 static inline unsigned int tdb_hash(const char *name)
178 unsigned value; /* Used to compute the hash value. */
179 unsigned i; /* Used to cycle through random values. */
181 /* Set the initial value from the key size. */
182 for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
183 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
185 return (1103515243 * value + 12345);
189 * Allocate a new symbols for use in the hash of exported symbols or
190 * the list of unresolved symbols per module
192 static struct symbol *alloc_symbol(const char *name, unsigned int weak,
195 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
197 memset(s, 0, sizeof(*s));
198 strcpy(s->name, name);
204 /* For the hash of exported symbols */
205 static struct symbol *new_symbol(const char *name, struct module *module,
211 hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
212 new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
213 new->module = module;
214 new->export = export;
218 static struct symbol *find_symbol(const char *name)
222 /* For our purposes, .foo matches foo. PPC64 needs this. */
226 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
227 if (strcmp(s->name, name) == 0)
233 static const struct {
237 { .str = "EXPORT_SYMBOL", .export = export_plain },
238 { .str = "EXPORT_UNUSED_SYMBOL", .export = export_unused },
239 { .str = "EXPORT_SYMBOL_GPL", .export = export_gpl },
240 { .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
241 { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
242 { .str = "(unknown)", .export = export_unknown },
246 static const char *export_str(enum export ex)
248 return export_list[ex].str;
251 static enum export export_no(const char *s)
256 return export_unknown;
257 for (i = 0; export_list[i].export != export_unknown; i++) {
258 if (strcmp(export_list[i].str, s) == 0)
259 return export_list[i].export;
261 return export_unknown;
264 static const char *sec_name(struct elf_info *elf, int secindex);
266 #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)
268 static enum export export_from_secname(struct elf_info *elf, unsigned int sec)
270 const char *secname = sec_name(elf, sec);
272 if (strstarts(secname, "___ksymtab+"))
274 else if (strstarts(secname, "___ksymtab_unused+"))
275 return export_unused;
276 else if (strstarts(secname, "___ksymtab_gpl+"))
278 else if (strstarts(secname, "___ksymtab_unused_gpl+"))
279 return export_unused_gpl;
280 else if (strstarts(secname, "___ksymtab_gpl_future+"))
281 return export_gpl_future;
283 return export_unknown;
286 static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
288 if (sec == elf->export_sec)
290 else if (sec == elf->export_unused_sec)
291 return export_unused;
292 else if (sec == elf->export_gpl_sec)
294 else if (sec == elf->export_unused_gpl_sec)
295 return export_unused_gpl;
296 else if (sec == elf->export_gpl_future_sec)
297 return export_gpl_future;
299 return export_unknown;
303 * Add an exported symbol - it may have already been added without a
304 * CRC, in this case just update the CRC
306 static struct symbol *sym_add_exported(const char *name, struct module *mod,
309 struct symbol *s = find_symbol(name);
312 s = new_symbol(name, mod, export);
315 warn("%s: '%s' exported twice. Previous export "
316 "was in %s%s\n", mod->name, name,
318 is_vmlinux(s->module->name) ?"":".ko");
320 /* In case Module.symvers was out of date */
325 s->vmlinux = is_vmlinux(mod->name);
331 static void sym_update_crc(const char *name, struct module *mod,
332 unsigned int crc, enum export export)
334 struct symbol *s = find_symbol(name);
337 s = new_symbol(name, mod, export);
338 /* Don't complain when we find it later. */
345 void *grab_file(const char *filename, unsigned long *size)
348 void *map = MAP_FAILED;
351 fd = open(filename, O_RDONLY);
358 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
362 if (map == MAP_FAILED)
368 * Return a copy of the next line in a mmap'ed file.
369 * spaces in the beginning of the line is trimmed away.
370 * Return a pointer to a static buffer.
372 char *get_next_line(unsigned long *pos, void *file, unsigned long size)
374 static char line[4096];
377 signed char *p = (signed char *)file + *pos;
380 for (; *pos < size ; (*pos)++) {
381 if (skip && isspace(*p)) {
386 if (*p != '\n' && (*pos < size)) {
390 break; /* Too long, stop */
401 void release_file(void *file, unsigned long size)
406 static int parse_elf(struct elf_info *info, const char *filename)
412 const char *secstrings;
413 unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
415 hdr = grab_file(filename, &info->size);
417 if (ignore_missing_files) {
418 fprintf(stderr, "%s: %s (ignored)\n", filename,
426 if (info->size < sizeof(*hdr)) {
427 /* file too small, assume this is an empty .o file */
430 /* Is this a valid ELF file? */
431 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
432 (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
433 (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
434 (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
435 /* Not an ELF file - silently ignore it */
438 /* Fix endianness in ELF header */
439 hdr->e_type = TO_NATIVE(hdr->e_type);
440 hdr->e_machine = TO_NATIVE(hdr->e_machine);
441 hdr->e_version = TO_NATIVE(hdr->e_version);
442 hdr->e_entry = TO_NATIVE(hdr->e_entry);
443 hdr->e_phoff = TO_NATIVE(hdr->e_phoff);
444 hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
445 hdr->e_flags = TO_NATIVE(hdr->e_flags);
446 hdr->e_ehsize = TO_NATIVE(hdr->e_ehsize);
447 hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
448 hdr->e_phnum = TO_NATIVE(hdr->e_phnum);
449 hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
450 hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
451 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
452 sechdrs = (void *)hdr + hdr->e_shoff;
453 info->sechdrs = sechdrs;
455 /* Check if file offset is correct */
456 if (hdr->e_shoff > info->size) {
457 fatal("section header offset=%lu in file '%s' is bigger than "
458 "filesize=%lu\n", (unsigned long)hdr->e_shoff,
459 filename, info->size);
463 if (hdr->e_shnum == SHN_UNDEF) {
465 * There are more than 64k sections,
466 * read count from .sh_size.
468 info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
471 info->num_sections = hdr->e_shnum;
473 if (hdr->e_shstrndx == SHN_XINDEX) {
474 info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
477 info->secindex_strings = hdr->e_shstrndx;
480 /* Fix endianness in section headers */
481 for (i = 0; i < info->num_sections; i++) {
482 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
483 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
484 sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags);
485 sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr);
486 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
487 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
488 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
489 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info);
490 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
491 sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize);
493 /* Find symbol table. */
494 secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
495 for (i = 1; i < info->num_sections; i++) {
497 int nobits = sechdrs[i].sh_type == SHT_NOBITS;
499 if (!nobits && sechdrs[i].sh_offset > info->size) {
500 fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
501 "sizeof(*hrd)=%zu\n", filename,
502 (unsigned long)sechdrs[i].sh_offset,
506 secname = secstrings + sechdrs[i].sh_name;
507 if (strcmp(secname, ".modinfo") == 0) {
509 fatal("%s has NOBITS .modinfo\n", filename);
510 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
511 info->modinfo_len = sechdrs[i].sh_size;
512 } else if (strcmp(secname, "__ksymtab") == 0)
513 info->export_sec = i;
514 else if (strcmp(secname, "__ksymtab_unused") == 0)
515 info->export_unused_sec = i;
516 else if (strcmp(secname, "__ksymtab_gpl") == 0)
517 info->export_gpl_sec = i;
518 else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
519 info->export_unused_gpl_sec = i;
520 else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
521 info->export_gpl_future_sec = i;
523 if (sechdrs[i].sh_type == SHT_SYMTAB) {
524 unsigned int sh_link_idx;
526 info->symtab_start = (void *)hdr +
527 sechdrs[i].sh_offset;
528 info->symtab_stop = (void *)hdr +
529 sechdrs[i].sh_offset + sechdrs[i].sh_size;
530 sh_link_idx = sechdrs[i].sh_link;
531 info->strtab = (void *)hdr +
532 sechdrs[sh_link_idx].sh_offset;
535 /* 32bit section no. table? ("more than 64k sections") */
536 if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
537 symtab_shndx_idx = i;
538 info->symtab_shndx_start = (void *)hdr +
539 sechdrs[i].sh_offset;
540 info->symtab_shndx_stop = (void *)hdr +
541 sechdrs[i].sh_offset + sechdrs[i].sh_size;
544 if (!info->symtab_start)
545 fatal("%s has no symtab?\n", filename);
547 /* Fix endianness in symbols */
548 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
549 sym->st_shndx = TO_NATIVE(sym->st_shndx);
550 sym->st_name = TO_NATIVE(sym->st_name);
551 sym->st_value = TO_NATIVE(sym->st_value);
552 sym->st_size = TO_NATIVE(sym->st_size);
555 if (symtab_shndx_idx != ~0U) {
557 if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
558 fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
559 filename, sechdrs[symtab_shndx_idx].sh_link,
562 for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
570 static void parse_elf_finish(struct elf_info *info)
572 release_file(info->hdr, info->size);
575 static int ignore_undef_symbol(struct elf_info *info, const char *symname)
577 /* ignore __this_module, it will be resolved shortly */
578 if (strcmp(symname, VMLINUX_SYMBOL_STR(__this_module)) == 0)
580 /* ignore global offset table */
581 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
583 if (info->hdr->e_machine == EM_PPC)
584 /* Special register function linked on all modules during final link of .ko */
585 if (strncmp(symname, "_restgpr_", sizeof("_restgpr_") - 1) == 0 ||
586 strncmp(symname, "_savegpr_", sizeof("_savegpr_") - 1) == 0 ||
587 strncmp(symname, "_rest32gpr_", sizeof("_rest32gpr_") - 1) == 0 ||
588 strncmp(symname, "_save32gpr_", sizeof("_save32gpr_") - 1) == 0 ||
589 strncmp(symname, "_restvr_", sizeof("_restvr_") - 1) == 0 ||
590 strncmp(symname, "_savevr_", sizeof("_savevr_") - 1) == 0)
592 if (info->hdr->e_machine == EM_PPC64)
593 /* Special register function linked on all modules during final link of .ko */
594 if (strncmp(symname, "_restgpr0_", sizeof("_restgpr0_") - 1) == 0 ||
595 strncmp(symname, "_savegpr0_", sizeof("_savegpr0_") - 1) == 0 ||
596 strncmp(symname, "_restvr_", sizeof("_restvr_") - 1) == 0 ||
597 strncmp(symname, "_savevr_", sizeof("_savevr_") - 1) == 0)
599 /* Do not ignore this symbol */
603 #define CRC_PFX VMLINUX_SYMBOL_STR(__crc_)
604 #define KSYMTAB_PFX VMLINUX_SYMBOL_STR(__ksymtab_)
606 static void handle_modversions(struct module *mod, struct elf_info *info,
607 Elf_Sym *sym, const char *symname)
612 if ((!is_vmlinux(mod->name) || mod->is_dot_o) &&
613 strncmp(symname, "__ksymtab", 9) == 0)
614 export = export_from_secname(info, get_secindex(info, sym));
616 export = export_from_sec(info, get_secindex(info, sym));
619 if (strncmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
620 crc = (unsigned int) sym->st_value;
621 sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
625 switch (sym->st_shndx) {
627 if (!strncmp(symname, "__gnu_lto_", sizeof("__gnu_lto_")-1)) {
628 /* Should warn here, but modpost runs before the linker */
630 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
633 /* undefined symbol */
634 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
635 ELF_ST_BIND(sym->st_info) != STB_WEAK)
637 if (ignore_undef_symbol(info, symname))
639 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
640 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
641 /* add compatibility with older glibc */
642 #ifndef STT_SPARC_REGISTER
643 #define STT_SPARC_REGISTER STT_REGISTER
645 if (info->hdr->e_machine == EM_SPARC ||
646 info->hdr->e_machine == EM_SPARCV9) {
647 /* Ignore register directives. */
648 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
650 if (symname[0] == '.') {
651 char *munged = strdup(symname);
653 munged[1] = toupper(munged[1]);
659 #ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX
660 if (symname[0] != '_')
665 mod->unres = alloc_symbol(symname,
666 ELF_ST_BIND(sym->st_info) == STB_WEAK,
670 /* All exported symbols */
671 if (strncmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
672 sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
675 if (strcmp(symname, VMLINUX_SYMBOL_STR(init_module)) == 0)
677 if (strcmp(symname, VMLINUX_SYMBOL_STR(cleanup_module)) == 0)
678 mod->has_cleanup = 1;
684 * Parse tag=value strings from .modinfo section
686 static char *next_string(char *string, unsigned long *secsize)
688 /* Skip non-zero chars */
691 if ((*secsize)-- <= 1)
695 /* Skip any zero padding. */
698 if ((*secsize)-- <= 1)
704 static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
705 const char *tag, char *info)
708 unsigned int taglen = strlen(tag);
709 unsigned long size = modinfo_len;
712 size -= info - (char *)modinfo;
713 modinfo = next_string(info, &size);
716 for (p = modinfo; p; p = next_string(p, &size)) {
717 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
718 return p + taglen + 1;
723 static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
727 return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
731 * Test if string s ends in string sub
734 static int strrcmp(const char *s, const char *sub)
742 sublen = strlen(sub);
744 if ((slen == 0) || (sublen == 0))
750 return memcmp(s + slen - sublen, sub, sublen);
753 static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
756 return elf->strtab + sym->st_name;
761 static const char *sec_name(struct elf_info *elf, int secindex)
763 Elf_Shdr *sechdrs = elf->sechdrs;
764 return (void *)elf->hdr +
765 elf->sechdrs[elf->secindex_strings].sh_offset +
766 sechdrs[secindex].sh_name;
769 static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr)
771 return (void *)elf->hdr +
772 elf->sechdrs[elf->secindex_strings].sh_offset +
776 /* The pattern is an array of simple patterns.
777 * "foo" will match an exact string equal to "foo"
778 * "*foo" will match a string that ends with "foo"
779 * "foo*" will match a string that begins with "foo"
780 * "*foo*" will match a string that contains "foo"
782 static int match(const char *sym, const char * const pat[])
787 const char *endp = p + strlen(p) - 1;
790 if (*p == '*' && *endp == '*') {
791 char *here, *bare = strndup(p + 1, strlen(p) - 2);
793 here = strstr(sym, bare);
799 else if (*p == '*') {
800 if (strrcmp(sym, p + 1) == 0)
804 else if (*endp == '*') {
805 if (strncmp(sym, p, strlen(p) - 1) == 0)
810 if (strcmp(p, sym) == 0)
818 /* sections that we do not want to do full section mismatch check on */
819 static const char *const section_white_list[] =
823 ".cranges", /* sh64 */
824 ".zdebug*", /* Compressed debug sections. */
825 ".GCC-command-line", /* mn10300 */
826 ".GCC.command.line", /* record-gcc-switches, non mn10300 */
827 ".mdebug*", /* alpha, score, mips etc. */
828 ".pdr", /* alpha, score, mips etc. */
833 ".xt.prop", /* xtensa */
834 ".xt.lit", /* xtensa */
835 ".arcextmap*", /* arc */
836 ".gnu.linkonce.arcext*", /* arc : modules */
842 * This is used to find sections missing the SHF_ALLOC flag.
843 * The cause of this is often a section specified in assembler
844 * without "ax" / "aw".
846 static void check_section(const char *modname, struct elf_info *elf,
849 const char *sec = sech_name(elf, sechdr);
851 if (sechdr->sh_type == SHT_PROGBITS &&
852 !(sechdr->sh_flags & SHF_ALLOC) &&
853 !match(sec, section_white_list)) {
854 warn("%s (%s): unexpected non-allocatable section.\n"
855 "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
856 "Note that for example <linux/init.h> contains\n"
857 "section definitions for use in .S files.\n\n",
864 #define ALL_INIT_DATA_SECTIONS \
865 ".init.setup", ".init.rodata", ".meminit.rodata", \
866 ".init.data", ".meminit.data"
867 #define ALL_EXIT_DATA_SECTIONS \
868 ".exit.data", ".memexit.data"
870 #define ALL_INIT_TEXT_SECTIONS \
871 ".init.text", ".meminit.text"
872 #define ALL_EXIT_TEXT_SECTIONS \
873 ".exit.text", ".memexit.text"
875 #define ALL_PCI_INIT_SECTIONS \
876 ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
877 ".pci_fixup_enable", ".pci_fixup_resume", \
878 ".pci_fixup_resume_early", ".pci_fixup_suspend"
880 #define ALL_XXXINIT_SECTIONS MEM_INIT_SECTIONS
881 #define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS
883 #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
884 #define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
886 #define DATA_SECTIONS ".data", ".data.rel"
887 #define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \
889 #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
890 ".fixup", ".entry.text", ".exception.text", ".text.*", \
893 #define INIT_SECTIONS ".init.*"
894 #define MEM_INIT_SECTIONS ".meminit.*"
896 #define EXIT_SECTIONS ".exit.*"
897 #define MEM_EXIT_SECTIONS ".memexit.*"
899 #define ALL_TEXT_SECTIONS ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \
900 TEXT_SECTIONS, OTHER_TEXT_SECTIONS
902 /* init data sections */
903 static const char *const init_data_sections[] =
904 { ALL_INIT_DATA_SECTIONS, NULL };
906 /* all init sections */
907 static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL };
909 /* All init and exit sections (code + data) */
910 static const char *const init_exit_sections[] =
911 {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
913 /* all text sections */
914 static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL };
917 static const char *const data_sections[] = { DATA_SECTIONS, NULL };
920 /* symbols in .data that may refer to init/exit sections */
921 #define DEFAULT_SYMBOL_WHITE_LIST \
923 "*_template", /* scsi uses *_template a lot */ \
924 "*_timer", /* arm uses ops structures named _timer a lot */ \
925 "*_sht", /* scsi also used *_sht to some extent */ \
931 static const char *const head_sections[] = { ".head.text*", NULL };
932 static const char *const linker_symbols[] =
933 { "__init_begin", "_sinittext", "_einittext", NULL };
934 static const char *const optim_symbols[] = { "*.constprop.*", NULL };
941 XXXINIT_TO_SOME_INIT,
942 XXXEXIT_TO_SOME_EXIT,
943 ANY_INIT_TO_ANY_EXIT,
944 ANY_EXIT_TO_ANY_INIT,
950 * Describe how to match sections on different criterias:
952 * @fromsec: Array of sections to be matched.
954 * @bad_tosec: Relocations applied to a section in @fromsec to a section in
955 * this array is forbidden (black-list). Can be empty.
957 * @good_tosec: Relocations applied to a section in @fromsec must be
958 * targetting sections in this array (white-list). Can be empty.
960 * @mismatch: Type of mismatch.
962 * @symbol_white_list: Do not match a relocation to a symbol in this list
963 * even if it is targetting a section in @bad_to_sec.
965 * @handler: Specific handler to call when a match is found. If NULL,
966 * default_mismatch_handler() will be called.
969 struct sectioncheck {
970 const char *fromsec[20];
971 const char *bad_tosec[20];
972 const char *good_tosec[20];
973 enum mismatch mismatch;
974 const char *symbol_white_list[20];
975 void (*handler)(const char *modname, struct elf_info *elf,
976 const struct sectioncheck* const mismatch,
977 Elf_Rela *r, Elf_Sym *sym, const char *fromsec);
981 static void extable_mismatch_handler(const char *modname, struct elf_info *elf,
982 const struct sectioncheck* const mismatch,
983 Elf_Rela *r, Elf_Sym *sym,
984 const char *fromsec);
986 static const struct sectioncheck sectioncheck[] = {
987 /* Do not reference init/exit code/data from
988 * normal code and data
991 .fromsec = { TEXT_SECTIONS, NULL },
992 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
993 .mismatch = TEXT_TO_ANY_INIT,
994 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
997 .fromsec = { DATA_SECTIONS, NULL },
998 .bad_tosec = { ALL_XXXINIT_SECTIONS, NULL },
999 .mismatch = DATA_TO_ANY_INIT,
1000 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1003 .fromsec = { DATA_SECTIONS, NULL },
1004 .bad_tosec = { INIT_SECTIONS, NULL },
1005 .mismatch = DATA_TO_ANY_INIT,
1006 .symbol_white_list = {
1007 "*_template", "*_timer", "*_sht", "*_ops",
1008 "*_probe", "*_probe_one", "*_console", NULL
1012 .fromsec = { TEXT_SECTIONS, NULL },
1013 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1014 .mismatch = TEXT_TO_ANY_EXIT,
1015 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1018 .fromsec = { DATA_SECTIONS, NULL },
1019 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1020 .mismatch = DATA_TO_ANY_EXIT,
1021 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1023 /* Do not reference init code/data from meminit code/data */
1025 .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
1026 .bad_tosec = { INIT_SECTIONS, NULL },
1027 .mismatch = XXXINIT_TO_SOME_INIT,
1028 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1030 /* Do not reference exit code/data from memexit code/data */
1032 .fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
1033 .bad_tosec = { EXIT_SECTIONS, NULL },
1034 .mismatch = XXXEXIT_TO_SOME_EXIT,
1035 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1037 /* Do not use exit code/data from init code */
1039 .fromsec = { ALL_INIT_SECTIONS, NULL },
1040 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1041 .mismatch = ANY_INIT_TO_ANY_EXIT,
1042 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1044 /* Do not use init code/data from exit code */
1046 .fromsec = { ALL_EXIT_SECTIONS, NULL },
1047 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1048 .mismatch = ANY_EXIT_TO_ANY_INIT,
1049 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1052 .fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
1053 .bad_tosec = { INIT_SECTIONS, NULL },
1054 .mismatch = ANY_INIT_TO_ANY_EXIT,
1055 .symbol_white_list = { NULL },
1057 /* Do not export init/exit functions or data */
1059 .fromsec = { "__ksymtab*", NULL },
1060 .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
1061 .mismatch = EXPORT_TO_INIT_EXIT,
1062 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1065 .fromsec = { "__ex_table", NULL },
1066 /* If you're adding any new black-listed sections in here, consider
1067 * adding a special 'printer' for them in scripts/check_extable.
1069 .bad_tosec = { ".altinstr_replacement", NULL },
1070 .good_tosec = {ALL_TEXT_SECTIONS , NULL},
1071 .mismatch = EXTABLE_TO_NON_TEXT,
1072 .handler = extable_mismatch_handler,
1076 static const struct sectioncheck *section_mismatch(
1077 const char *fromsec, const char *tosec)
1080 int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
1081 const struct sectioncheck *check = §ioncheck[0];
1084 * The target section could be the SHT_NUL section when we're
1085 * handling relocations to un-resolved symbols, trying to match it
1086 * doesn't make much sense and causes build failures on parisc and
1087 * mn10300 architectures.
1092 for (i = 0; i < elems; i++) {
1093 if (match(fromsec, check->fromsec)) {
1094 if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
1096 if (check->good_tosec[0] && !match(tosec, check->good_tosec))
1105 * Whitelist to allow certain references to pass with no warning.
1108 * If a module parameter is declared __initdata and permissions=0
1109 * then this is legal despite the warning generated.
1110 * We cannot see value of permissions here, so just ignore
1112 * The pattern is identified by:
1113 * tosec = .init.data
1118 * module_param_call() ops can refer to __init set function if permissions=0
1119 * The pattern is identified by:
1120 * tosec = .init.text
1122 * atsym = __param_ops_*
1125 * Many drivers utilise a *driver container with references to
1126 * add, remove, probe functions etc.
1127 * the pattern is identified by:
1128 * tosec = init or exit section
1129 * fromsec = data section
1130 * atsym = *driver, *_template, *_sht, *_ops, *_probe,
1131 * *probe_one, *_console, *_timer
1134 * Whitelist all references from .head.text to any init section
1137 * Some symbols belong to init section but still it is ok to reference
1138 * these from non-init sections as these symbols don't have any memory
1139 * allocated for them and symbol address and value are same. So even
1140 * if init section is freed, its ok to reference those symbols.
1141 * For ex. symbols marking the init section boundaries.
1142 * This pattern is identified by
1143 * refsymname = __init_begin, _sinittext, _einittext
1146 * GCC may optimize static inlines when fed constant arg(s) resulting
1147 * in functions like cpumask_empty() -- generating an associated symbol
1148 * cpumask_empty.constprop.3 that appears in the audit. If the const that
1149 * is passed in comes from __init, like say nmi_ipi_mask, we get a
1150 * meaningless section warning. May need to add isra symbols too...
1151 * This pattern is identified by
1152 * tosec = init section
1153 * fromsec = text section
1154 * refsymname = *.constprop.*
1157 static int secref_whitelist(const struct sectioncheck *mismatch,
1158 const char *fromsec, const char *fromsym,
1159 const char *tosec, const char *tosym)
1161 /* Check for pattern 1 */
1162 if (match(tosec, init_data_sections) &&
1163 match(fromsec, data_sections) &&
1164 (strncmp(fromsym, "__param", strlen("__param")) == 0))
1167 /* Check for pattern 1a */
1168 if (strcmp(tosec, ".init.text") == 0 &&
1169 match(fromsec, data_sections) &&
1170 (strncmp(fromsym, "__param_ops_", strlen("__param_ops_")) == 0))
1173 /* Check for pattern 2 */
1174 if (match(tosec, init_exit_sections) &&
1175 match(fromsec, data_sections) &&
1176 match(fromsym, mismatch->symbol_white_list))
1179 /* Check for pattern 3 */
1180 if (match(fromsec, head_sections) &&
1181 match(tosec, init_sections))
1184 /* Check for pattern 4 */
1185 if (match(tosym, linker_symbols))
1188 /* Check for pattern 5 */
1189 if (match(fromsec, text_sections) &&
1190 match(tosec, init_sections) &&
1191 match(fromsym, optim_symbols))
1198 * Find symbol based on relocation record info.
1199 * In some cases the symbol supplied is a valid symbol so
1200 * return refsym. If st_name != 0 we assume this is a valid symbol.
1201 * In other cases the symbol needs to be looked up in the symbol table
1202 * based on section and address.
1204 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
1208 Elf_Sym *near = NULL;
1209 Elf64_Sword distance = 20;
1211 unsigned int relsym_secindex;
1213 if (relsym->st_name != 0)
1216 relsym_secindex = get_secindex(elf, relsym);
1217 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1218 if (get_secindex(elf, sym) != relsym_secindex)
1220 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
1222 if (sym->st_value == addr)
1224 /* Find a symbol nearby - addr are maybe negative */
1225 d = sym->st_value - addr;
1227 d = addr - sym->st_value;
1233 /* We need a close match */
1240 static inline int is_arm_mapping_symbol(const char *str)
1242 return str[0] == '$' && strchr("axtd", str[1])
1243 && (str[2] == '\0' || str[2] == '.');
1247 * If there's no name there, ignore it; likewise, ignore it if it's
1248 * one of the magic symbols emitted used by current ARM tools.
1250 * Otherwise if find_symbols_between() returns those symbols, they'll
1251 * fail the whitelist tests and cause lots of false alarms ... fixable
1252 * only by merging __exit and __init sections into __text, bloating
1253 * the kernel (which is especially evil on embedded platforms).
1255 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1257 const char *name = elf->strtab + sym->st_name;
1259 if (!name || !strlen(name))
1261 return !is_arm_mapping_symbol(name);
1265 * Find symbols before or equal addr and after addr - in the section sec.
1266 * If we find two symbols with equal offset prefer one with a valid name.
1267 * The ELF format may have a better way to detect what type of symbol
1268 * it is, but this works for now.
1270 static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1274 Elf_Sym *near = NULL;
1275 Elf_Addr distance = ~0;
1277 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1280 if (is_shndx_special(sym->st_shndx))
1282 symsec = sec_name(elf, get_secindex(elf, sym));
1283 if (strcmp(symsec, sec) != 0)
1285 if (!is_valid_name(elf, sym))
1287 if (sym->st_value <= addr) {
1288 if ((addr - sym->st_value) < distance) {
1289 distance = addr - sym->st_value;
1291 } else if ((addr - sym->st_value) == distance) {
1300 * Convert a section name to the function/data attribute
1301 * .init.text => __init
1302 * .memexitconst => __memconst
1305 * The memory of returned value has been allocated on a heap. The user of this
1306 * method should free it after usage.
1308 static char *sec2annotation(const char *s)
1310 if (match(s, init_exit_sections)) {
1311 char *p = malloc(20);
1318 while (*s && *s != '.')
1323 if (strstr(s, "rodata") != NULL)
1324 strcat(p, "const ");
1325 else if (strstr(s, "data") != NULL)
1335 static int is_function(Elf_Sym *sym)
1338 return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1343 static void print_section_list(const char * const list[20])
1345 const char *const *s = list;
1348 fprintf(stderr, "%s", *s);
1351 fprintf(stderr, ", ");
1353 fprintf(stderr, "\n");
1356 static inline void get_pretty_name(int is_func, const char** name, const char** name_p)
1359 case 0: *name = "variable"; *name_p = ""; break;
1360 case 1: *name = "function"; *name_p = "()"; break;
1361 default: *name = "(unknown reference)"; *name_p = ""; break;
1366 * Print a warning about a section mismatch.
1367 * Try to find symbols near it so user can find it.
1368 * Check whitelist before warning - it may be a false positive.
1370 static void report_sec_mismatch(const char *modname,
1371 const struct sectioncheck *mismatch,
1372 const char *fromsec,
1373 unsigned long long fromaddr,
1374 const char *fromsym,
1376 const char *tosec, const char *tosym,
1379 const char *from, *from_p;
1380 const char *to, *to_p;
1384 sec_mismatch_count++;
1385 if (!sec_mismatch_verbose)
1388 get_pretty_name(from_is_func, &from, &from_p);
1389 get_pretty_name(to_is_func, &to, &to_p);
1391 warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1392 "to the %s %s:%s%s\n",
1393 modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1396 switch (mismatch->mismatch) {
1397 case TEXT_TO_ANY_INIT:
1398 prl_from = sec2annotation(fromsec);
1399 prl_to = sec2annotation(tosec);
1401 "The function %s%s() references\n"
1403 "This is often because %s lacks a %s\n"
1404 "annotation or the annotation of %s is wrong.\n",
1406 to, prl_to, tosym, to_p,
1407 fromsym, prl_to, tosym);
1411 case DATA_TO_ANY_INIT: {
1412 prl_to = sec2annotation(tosec);
1414 "The variable %s references\n"
1416 "If the reference is valid then annotate the\n"
1417 "variable with __init* or __refdata (see linux/init.h) "
1418 "or name the variable:\n",
1419 fromsym, to, prl_to, tosym, to_p);
1420 print_section_list(mismatch->symbol_white_list);
1424 case TEXT_TO_ANY_EXIT:
1425 prl_to = sec2annotation(tosec);
1427 "The function %s() references a %s in an exit section.\n"
1428 "Often the %s %s%s has valid usage outside the exit section\n"
1429 "and the fix is to remove the %sannotation of %s.\n",
1430 fromsym, to, to, tosym, to_p, prl_to, tosym);
1433 case DATA_TO_ANY_EXIT: {
1434 prl_to = sec2annotation(tosec);
1436 "The variable %s references\n"
1438 "If the reference is valid then annotate the\n"
1439 "variable with __exit* (see linux/init.h) or "
1440 "name the variable:\n",
1441 fromsym, to, prl_to, tosym, to_p);
1442 print_section_list(mismatch->symbol_white_list);
1446 case XXXINIT_TO_SOME_INIT:
1447 case XXXEXIT_TO_SOME_EXIT:
1448 prl_from = sec2annotation(fromsec);
1449 prl_to = sec2annotation(tosec);
1451 "The %s %s%s%s references\n"
1453 "If %s is only used by %s then\n"
1454 "annotate %s with a matching annotation.\n",
1455 from, prl_from, fromsym, from_p,
1456 to, prl_to, tosym, to_p,
1457 tosym, fromsym, tosym);
1461 case ANY_INIT_TO_ANY_EXIT:
1462 prl_from = sec2annotation(fromsec);
1463 prl_to = sec2annotation(tosec);
1465 "The %s %s%s%s references\n"
1467 "This is often seen when error handling "
1468 "in the init function\n"
1469 "uses functionality in the exit path.\n"
1470 "The fix is often to remove the %sannotation of\n"
1471 "%s%s so it may be used outside an exit section.\n",
1472 from, prl_from, fromsym, from_p,
1473 to, prl_to, tosym, to_p,
1474 prl_to, tosym, to_p);
1478 case ANY_EXIT_TO_ANY_INIT:
1479 prl_from = sec2annotation(fromsec);
1480 prl_to = sec2annotation(tosec);
1482 "The %s %s%s%s references\n"
1484 "This is often seen when error handling "
1485 "in the exit function\n"
1486 "uses functionality in the init path.\n"
1487 "The fix is often to remove the %sannotation of\n"
1488 "%s%s so it may be used outside an init section.\n",
1489 from, prl_from, fromsym, from_p,
1490 to, prl_to, tosym, to_p,
1491 prl_to, tosym, to_p);
1495 case EXPORT_TO_INIT_EXIT:
1496 prl_to = sec2annotation(tosec);
1498 "The symbol %s is exported and annotated %s\n"
1499 "Fix this by removing the %sannotation of %s "
1500 "or drop the export.\n",
1501 tosym, prl_to, prl_to, tosym);
1504 case EXTABLE_TO_NON_TEXT:
1505 fatal("There's a special handler for this mismatch type, "
1506 "we should never get here.");
1509 fprintf(stderr, "\n");
1512 static void default_mismatch_handler(const char *modname, struct elf_info *elf,
1513 const struct sectioncheck* const mismatch,
1514 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1520 const char *fromsym;
1522 from = find_elf_symbol2(elf, r->r_offset, fromsec);
1523 fromsym = sym_name(elf, from);
1525 if (!strncmp(fromsym, "reference___initcall",
1526 sizeof("reference___initcall")-1))
1529 tosec = sec_name(elf, get_secindex(elf, sym));
1530 to = find_elf_symbol(elf, r->r_addend, sym);
1531 tosym = sym_name(elf, to);
1533 /* check whitelist - we may ignore it */
1534 if (secref_whitelist(mismatch,
1535 fromsec, fromsym, tosec, tosym)) {
1536 report_sec_mismatch(modname, mismatch,
1537 fromsec, r->r_offset, fromsym,
1538 is_function(from), tosec, tosym,
1543 static int is_executable_section(struct elf_info* elf, unsigned int section_index)
1545 if (section_index > elf->num_sections)
1546 fatal("section_index is outside elf->num_sections!\n");
1548 return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR);
1552 * We rely on a gross hack in section_rel[a]() calling find_extable_entry_size()
1553 * to know the sizeof(struct exception_table_entry) for the target architecture.
1555 static unsigned int extable_entry_size = 0;
1556 static void find_extable_entry_size(const char* const sec, const Elf_Rela* r)
1559 * If we're currently checking the second relocation within __ex_table,
1560 * that relocation offset tells us the offsetof(struct
1561 * exception_table_entry, fixup) which is equal to sizeof(struct
1562 * exception_table_entry) divided by two. We use that to our advantage
1563 * since there's no portable way to get that size as every architecture
1564 * seems to go with different sized types. Not pretty but better than
1565 * hard-coding the size for every architecture..
1567 if (!extable_entry_size)
1568 extable_entry_size = r->r_offset * 2;
1571 static inline bool is_extable_fault_address(Elf_Rela *r)
1574 * extable_entry_size is only discovered after we've handled the
1575 * _second_ relocation in __ex_table, so only abort when we're not
1576 * handling the first reloc and extable_entry_size is zero.
1578 if (r->r_offset && extable_entry_size == 0)
1579 fatal("extable_entry size hasn't been discovered!\n");
1581 return ((r->r_offset == 0) ||
1582 (r->r_offset % extable_entry_size == 0));
1585 #define is_second_extable_reloc(Start, Cur, Sec) \
1586 (((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0))
1588 static void report_extable_warnings(const char* modname, struct elf_info* elf,
1589 const struct sectioncheck* const mismatch,
1590 Elf_Rela* r, Elf_Sym* sym,
1591 const char* fromsec, const char* tosec)
1593 Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec);
1594 const char* fromsym_name = sym_name(elf, fromsym);
1595 Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym);
1596 const char* tosym_name = sym_name(elf, tosym);
1597 const char* from_pretty_name;
1598 const char* from_pretty_name_p;
1599 const char* to_pretty_name;
1600 const char* to_pretty_name_p;
1602 get_pretty_name(is_function(fromsym),
1603 &from_pretty_name, &from_pretty_name_p);
1604 get_pretty_name(is_function(tosym),
1605 &to_pretty_name, &to_pretty_name_p);
1607 warn("%s(%s+0x%lx): Section mismatch in reference"
1608 " from the %s %s%s to the %s %s:%s%s\n",
1609 modname, fromsec, (long)r->r_offset, from_pretty_name,
1610 fromsym_name, from_pretty_name_p,
1611 to_pretty_name, tosec, tosym_name, to_pretty_name_p);
1613 if (!match(tosec, mismatch->bad_tosec) &&
1614 is_executable_section(elf, get_secindex(elf, sym)))
1616 "The relocation at %s+0x%lx references\n"
1617 "section \"%s\" which is not in the list of\n"
1618 "authorized sections. If you're adding a new section\n"
1619 "and/or if this reference is valid, add \"%s\" to the\n"
1620 "list of authorized sections to jump to on fault.\n"
1621 "This can be achieved by adding \"%s\" to \n"
1622 "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
1623 fromsec, (long)r->r_offset, tosec, tosec, tosec);
1626 static void extable_mismatch_handler(const char* modname, struct elf_info *elf,
1627 const struct sectioncheck* const mismatch,
1628 Elf_Rela* r, Elf_Sym* sym,
1629 const char *fromsec)
1631 const char* tosec = sec_name(elf, get_secindex(elf, sym));
1633 sec_mismatch_count++;
1635 if (sec_mismatch_verbose)
1636 report_extable_warnings(modname, elf, mismatch, r, sym,
1639 if (match(tosec, mismatch->bad_tosec))
1640 fatal("The relocation at %s+0x%lx references\n"
1641 "section \"%s\" which is black-listed.\n"
1642 "Something is seriously wrong and should be fixed.\n"
1643 "You might get more information about where this is\n"
1644 "coming from by using scripts/check_extable.sh %s\n",
1645 fromsec, (long)r->r_offset, tosec, modname);
1646 else if (!is_executable_section(elf, get_secindex(elf, sym))) {
1647 if (is_extable_fault_address(r))
1648 fatal("The relocation at %s+0x%lx references\n"
1649 "section \"%s\" which is not executable, IOW\n"
1650 "it is not possible for the kernel to fault\n"
1651 "at that address. Something is seriously wrong\n"
1652 "and should be fixed.\n",
1653 fromsec, (long)r->r_offset, tosec);
1655 fatal("The relocation at %s+0x%lx references\n"
1656 "section \"%s\" which is not executable, IOW\n"
1657 "the kernel will fault if it ever tries to\n"
1658 "jump to it. Something is seriously wrong\n"
1659 "and should be fixed.\n",
1660 fromsec, (long)r->r_offset, tosec);
1664 static void check_section_mismatch(const char *modname, struct elf_info *elf,
1665 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1667 const char *tosec = sec_name(elf, get_secindex(elf, sym));;
1668 const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec);
1671 if (mismatch->handler)
1672 mismatch->handler(modname, elf, mismatch,
1675 default_mismatch_handler(modname, elf, mismatch,
1680 static unsigned int *reloc_location(struct elf_info *elf,
1681 Elf_Shdr *sechdr, Elf_Rela *r)
1683 Elf_Shdr *sechdrs = elf->sechdrs;
1684 int section = sechdr->sh_info;
1686 return (void *)elf->hdr + sechdrs[section].sh_offset +
1690 static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1692 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1693 unsigned int *location = reloc_location(elf, sechdr, r);
1697 r->r_addend = TO_NATIVE(*location);
1700 r->r_addend = TO_NATIVE(*location) + 4;
1701 /* For CONFIG_RELOCATABLE=y */
1702 if (elf->hdr->e_type == ET_EXEC)
1703 r->r_addend += r->r_offset;
1710 #define R_ARM_CALL 28
1712 #ifndef R_ARM_JUMP24
1713 #define R_ARM_JUMP24 29
1716 #ifndef R_ARM_THM_CALL
1717 #define R_ARM_THM_CALL 10
1719 #ifndef R_ARM_THM_JUMP24
1720 #define R_ARM_THM_JUMP24 30
1722 #ifndef R_ARM_THM_JUMP19
1723 #define R_ARM_THM_JUMP19 51
1726 static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1728 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1732 /* From ARM ABI: (S + A) | T */
1733 r->r_addend = (int)(long)
1734 (elf->symtab_start + ELF_R_SYM(r->r_info));
1739 case R_ARM_THM_CALL:
1740 case R_ARM_THM_JUMP24:
1741 case R_ARM_THM_JUMP19:
1742 /* From ARM ABI: ((S + A) | T) - P */
1743 r->r_addend = (int)(long)(elf->hdr +
1745 (r->r_offset - sechdr->sh_addr));
1753 static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1755 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1756 unsigned int *location = reloc_location(elf, sechdr, r);
1759 if (r_typ == R_MIPS_HI16)
1760 return 1; /* skip this */
1761 inst = TO_NATIVE(*location);
1764 r->r_addend = inst & 0xffff;
1767 r->r_addend = (inst & 0x03ffffff) << 2;
1776 static void section_rela(const char *modname, struct elf_info *elf,
1783 const char *fromsec;
1785 Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1786 Elf_Rela *stop = (void *)start + sechdr->sh_size;
1788 fromsec = sech_name(elf, sechdr);
1789 fromsec += strlen(".rela");
1790 /* if from section (name) is know good then skip it */
1791 if (match(fromsec, section_white_list))
1794 for (rela = start; rela < stop; rela++) {
1795 r.r_offset = TO_NATIVE(rela->r_offset);
1796 #if KERNEL_ELFCLASS == ELFCLASS64
1797 if (elf->hdr->e_machine == EM_MIPS) {
1799 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1800 r_sym = TO_NATIVE(r_sym);
1801 r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1802 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1804 r.r_info = TO_NATIVE(rela->r_info);
1805 r_sym = ELF_R_SYM(r.r_info);
1808 r.r_info = TO_NATIVE(rela->r_info);
1809 r_sym = ELF_R_SYM(r.r_info);
1811 r.r_addend = TO_NATIVE(rela->r_addend);
1812 sym = elf->symtab_start + r_sym;
1813 /* Skip special sections */
1814 if (is_shndx_special(sym->st_shndx))
1816 if (is_second_extable_reloc(start, rela, fromsec))
1817 find_extable_entry_size(fromsec, &r);
1818 check_section_mismatch(modname, elf, &r, sym, fromsec);
1822 static void section_rel(const char *modname, struct elf_info *elf,
1829 const char *fromsec;
1831 Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1832 Elf_Rel *stop = (void *)start + sechdr->sh_size;
1834 fromsec = sech_name(elf, sechdr);
1835 fromsec += strlen(".rel");
1836 /* if from section (name) is know good then skip it */
1837 if (match(fromsec, section_white_list))
1840 for (rel = start; rel < stop; rel++) {
1841 r.r_offset = TO_NATIVE(rel->r_offset);
1842 #if KERNEL_ELFCLASS == ELFCLASS64
1843 if (elf->hdr->e_machine == EM_MIPS) {
1845 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1846 r_sym = TO_NATIVE(r_sym);
1847 r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1848 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1850 r.r_info = TO_NATIVE(rel->r_info);
1851 r_sym = ELF_R_SYM(r.r_info);
1854 r.r_info = TO_NATIVE(rel->r_info);
1855 r_sym = ELF_R_SYM(r.r_info);
1858 switch (elf->hdr->e_machine) {
1860 if (addend_386_rel(elf, sechdr, &r))
1864 if (addend_arm_rel(elf, sechdr, &r))
1868 if (addend_mips_rel(elf, sechdr, &r))
1872 sym = elf->symtab_start + r_sym;
1873 /* Skip special sections */
1874 if (is_shndx_special(sym->st_shndx))
1876 if (is_second_extable_reloc(start, rel, fromsec))
1877 find_extable_entry_size(fromsec, &r);
1878 check_section_mismatch(modname, elf, &r, sym, fromsec);
1883 * A module includes a number of sections that are discarded
1884 * either when loaded or when used as built-in.
1885 * For loaded modules all functions marked __init and all data
1886 * marked __initdata will be discarded when the module has been initialized.
1887 * Likewise for modules used built-in the sections marked __exit
1888 * are discarded because __exit marked function are supposed to be called
1889 * only when a module is unloaded which never happens for built-in modules.
1890 * The check_sec_ref() function traverses all relocation records
1891 * to find all references to a section that reference a section that will
1892 * be discarded and warns about it.
1894 static void check_sec_ref(struct module *mod, const char *modname,
1895 struct elf_info *elf)
1898 Elf_Shdr *sechdrs = elf->sechdrs;
1900 /* Walk through all sections */
1901 for (i = 0; i < elf->num_sections; i++) {
1902 check_section(modname, elf, &elf->sechdrs[i]);
1903 /* We want to process only relocation sections and not .init */
1904 if (sechdrs[i].sh_type == SHT_RELA)
1905 section_rela(modname, elf, &elf->sechdrs[i]);
1906 else if (sechdrs[i].sh_type == SHT_REL)
1907 section_rel(modname, elf, &elf->sechdrs[i]);
1911 static char *remove_dot(char *s)
1913 size_t n = strcspn(s, ".");
1916 size_t m = strspn(s + n + 1, "0123456789");
1917 if (m && (s[n + m] == '.' || s[n + m] == 0))
1923 static void read_symbols(char *modname)
1925 const char *symname;
1929 struct elf_info info = { };
1932 if (!parse_elf(&info, modname))
1935 mod = new_module(modname);
1937 /* When there's no vmlinux, don't print warnings about
1938 * unresolved symbols (since there'll be too many ;) */
1939 if (is_vmlinux(modname)) {
1944 license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1945 if (info.modinfo && !license && !is_vmlinux(modname))
1946 warn("modpost: missing MODULE_LICENSE() in %s\n"
1947 "see include/linux/module.h for "
1948 "more information\n", modname);
1950 if (license_is_gpl_compatible(license))
1951 mod->gpl_compatible = 1;
1953 mod->gpl_compatible = 0;
1956 license = get_next_modinfo(info.modinfo, info.modinfo_len,
1957 "license", license);
1960 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1961 symname = remove_dot(info.strtab + sym->st_name);
1963 handle_modversions(mod, &info, sym, symname);
1964 handle_moddevtable(mod, &info, sym, symname);
1966 if (!is_vmlinux(modname) ||
1967 (is_vmlinux(modname) && vmlinux_section_warnings))
1968 check_sec_ref(mod, modname, &info);
1970 version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1972 maybe_frob_rcs_version(modname, version, info.modinfo,
1973 version - (char *)info.hdr);
1974 if (version || (all_versions && !is_vmlinux(modname)))
1975 get_src_version(modname, mod->srcversion,
1976 sizeof(mod->srcversion)-1);
1978 parse_elf_finish(&info);
1980 /* Our trick to get versioning for module struct etc. - it's
1981 * never passed as an argument to an exported function, so
1982 * the automatic versioning doesn't pick it up, but it's really
1983 * important anyhow */
1985 mod->unres = alloc_symbol("module_layout", 0, mod->unres);
1988 static void read_symbols_from_files(const char *filename)
1991 char fname[PATH_MAX];
1993 if (strcmp(filename, "-") != 0) {
1994 in = fopen(filename, "r");
1996 fatal("Can't open filenames file %s: %m", filename);
1999 while (fgets(fname, PATH_MAX, in) != NULL) {
2000 if (strends(fname, "\n"))
2001 fname[strlen(fname)-1] = '\0';
2002 read_symbols(fname);
2011 /* We first write the generated file into memory using the
2012 * following helper, then compare to the file on disk and
2013 * only update the later if anything changed */
2015 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
2016 const char *fmt, ...)
2023 len = vsnprintf(tmp, SZ, fmt, ap);
2024 buf_write(buf, tmp, len);
2028 void buf_write(struct buffer *buf, const char *s, int len)
2030 if (buf->size - buf->pos < len) {
2031 buf->size += len + SZ;
2032 buf->p = realloc(buf->p, buf->size);
2034 strncpy(buf->p + buf->pos, s, len);
2038 static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
2040 const char *e = is_vmlinux(m) ?"":".ko";
2044 fatal("modpost: GPL-incompatible module %s%s "
2045 "uses GPL-only symbol '%s'\n", m, e, s);
2047 case export_unused_gpl:
2048 fatal("modpost: GPL-incompatible module %s%s "
2049 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
2051 case export_gpl_future:
2052 warn("modpost: GPL-incompatible module %s%s "
2053 "uses future GPL-only symbol '%s'\n", m, e, s);
2057 case export_unknown:
2063 static void check_for_unused(enum export exp, const char *m, const char *s)
2065 const char *e = is_vmlinux(m) ?"":".ko";
2069 case export_unused_gpl:
2070 warn("modpost: module %s%s "
2071 "uses symbol '%s' marked UNUSED\n", m, e, s);
2079 static void check_exports(struct module *mod)
2081 struct symbol *s, *exp;
2083 for (s = mod->unres; s; s = s->next) {
2084 const char *basename;
2085 exp = find_symbol(s->name);
2086 if (!exp || exp->module == mod)
2088 basename = strrchr(mod->name, '/');
2092 basename = mod->name;
2093 if (!mod->gpl_compatible)
2094 check_for_gpl_usage(exp->export, basename, exp->name);
2095 check_for_unused(exp->export, basename, exp->name);
2100 * Header for the generated file
2102 static void add_header(struct buffer *b, struct module *mod)
2104 buf_printf(b, "#include <linux/module.h>\n");
2105 buf_printf(b, "#include <linux/vermagic.h>\n");
2106 buf_printf(b, "#include <linux/compiler.h>\n");
2107 buf_printf(b, "\n");
2108 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
2109 buf_printf(b, "\n");
2110 buf_printf(b, "__visible struct module __this_module\n");
2111 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
2112 buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
2114 buf_printf(b, "\t.init = init_module,\n");
2115 if (mod->has_cleanup)
2116 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
2117 "\t.exit = cleanup_module,\n"
2119 buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
2120 buf_printf(b, "};\n");
2123 static void add_intree_flag(struct buffer *b, int is_intree)
2126 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
2129 static void add_staging_flag(struct buffer *b, const char *name)
2131 static const char *staging_dir = "drivers/staging";
2133 if (strncmp(staging_dir, name, strlen(staging_dir)) == 0)
2134 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
2137 /* In kernel, this size is defined in linux/module.h;
2138 * here we use Elf_Addr instead of long for covering cross-compile
2140 #define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
2143 * Record CRCs for unresolved symbols
2145 static int add_versions(struct buffer *b, struct module *mod)
2147 struct symbol *s, *exp;
2150 for (s = mod->unres; s; s = s->next) {
2151 exp = find_symbol(s->name);
2152 if (!exp || exp->module == mod) {
2153 if (have_vmlinux && !s->weak) {
2154 if (warn_unresolved) {
2155 warn("\"%s\" [%s.ko] undefined!\n",
2156 s->name, mod->name);
2158 merror("\"%s\" [%s.ko] undefined!\n",
2159 s->name, mod->name);
2165 s->module = exp->module;
2166 s->crc_valid = exp->crc_valid;
2173 buf_printf(b, "\n");
2174 buf_printf(b, "static const struct modversion_info ____versions[]\n");
2175 buf_printf(b, "__used\n");
2176 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
2178 for (s = mod->unres; s; s = s->next) {
2181 if (!s->crc_valid) {
2182 warn("\"%s\" [%s.ko] has no CRC!\n",
2183 s->name, mod->name);
2186 if (strlen(s->name) >= MODULE_NAME_LEN) {
2187 merror("too long symbol \"%s\" [%s.ko]\n",
2188 s->name, mod->name);
2192 buf_printf(b, "\t{ %#8x, __VMLINUX_SYMBOL_STR(%s) },\n",
2196 buf_printf(b, "};\n");
2201 static void add_depends(struct buffer *b, struct module *mod,
2202 struct module *modules)
2208 for (m = modules; m; m = m->next)
2209 m->seen = is_vmlinux(m->name);
2211 buf_printf(b, "\n");
2212 buf_printf(b, "static const char __module_depends[]\n");
2213 buf_printf(b, "__used\n");
2214 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
2215 buf_printf(b, "\"depends=");
2216 for (s = mod->unres; s; s = s->next) {
2221 if (s->module->seen)
2224 s->module->seen = 1;
2225 p = strrchr(s->module->name, '/');
2229 p = s->module->name;
2230 buf_printf(b, "%s%s", first ? "" : ",", p);
2233 buf_printf(b, "\";\n");
2236 static void add_srcversion(struct buffer *b, struct module *mod)
2238 if (mod->srcversion[0]) {
2239 buf_printf(b, "\n");
2240 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
2245 static void write_if_changed(struct buffer *b, const char *fname)
2251 file = fopen(fname, "r");
2255 if (fstat(fileno(file), &st) < 0)
2258 if (st.st_size != b->pos)
2261 tmp = NOFAIL(malloc(b->pos));
2262 if (fread(tmp, 1, b->pos, file) != b->pos)
2265 if (memcmp(tmp, b->p, b->pos) != 0)
2277 file = fopen(fname, "w");
2282 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
2289 /* parse Module.symvers file. line format:
2290 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
2292 static void read_dump(const char *fname, unsigned int kernel)
2294 unsigned long size, pos = 0;
2295 void *file = grab_file(fname, &size);
2299 /* No symbol versions, silently ignore */
2302 while ((line = get_next_line(&pos, file, size))) {
2303 char *symname, *modname, *d, *export, *end;
2308 if (!(symname = strchr(line, '\t')))
2311 if (!(modname = strchr(symname, '\t')))
2314 if ((export = strchr(modname, '\t')) != NULL)
2316 if (export && ((end = strchr(export, '\t')) != NULL))
2318 crc = strtoul(line, &d, 16);
2319 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2321 mod = find_module(modname);
2323 if (is_vmlinux(modname))
2325 mod = new_module(modname);
2328 s = sym_add_exported(symname, mod, export_no(export));
2331 sym_update_crc(symname, mod, crc, export_no(export));
2333 release_file(file, size);
2336 release_file(file, size);
2337 fatal("parse error in symbol dump file\n");
2340 /* For normal builds always dump all symbols.
2341 * For external modules only dump symbols
2342 * that are not read from kernel Module.symvers.
2344 static int dump_sym(struct symbol *sym)
2346 if (!external_module)
2348 if (sym->vmlinux || sym->kernel)
2353 static void write_dump(const char *fname)
2355 struct buffer buf = { };
2356 struct symbol *symbol;
2359 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
2360 symbol = symbolhash[n];
2362 if (dump_sym(symbol))
2363 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
2364 symbol->crc, symbol->name,
2365 symbol->module->name,
2366 export_str(symbol->export));
2367 symbol = symbol->next;
2370 write_if_changed(&buf, fname);
2373 struct ext_sym_list {
2374 struct ext_sym_list *next;
2378 int main(int argc, char **argv)
2381 struct buffer buf = { };
2382 char *kernel_read = NULL, *module_read = NULL;
2383 char *dump_write = NULL, *files_source = NULL;
2386 struct ext_sym_list *extsym_iter;
2387 struct ext_sym_list *extsym_start = NULL;
2389 while ((opt = getopt(argc, argv, "i:I:e:mnsST:o:awM:K:E")) != -1) {
2392 kernel_read = optarg;
2395 module_read = optarg;
2396 external_module = 1;
2399 external_module = 1;
2401 NOFAIL(malloc(sizeof(*extsym_iter)));
2402 extsym_iter->next = extsym_start;
2403 extsym_iter->file = optarg;
2404 extsym_start = extsym_iter;
2410 ignore_missing_files = 1;
2413 dump_write = optarg;
2419 vmlinux_section_warnings = 0;
2422 sec_mismatch_verbose = 0;
2425 files_source = optarg;
2428 warn_unresolved = 1;
2431 sec_mismatch_fatal = 1;
2439 read_dump(kernel_read, 1);
2441 read_dump(module_read, 0);
2442 while (extsym_start) {
2443 read_dump(extsym_start->file, 0);
2444 extsym_iter = extsym_start->next;
2446 extsym_start = extsym_iter;
2449 while (optind < argc)
2450 read_symbols(argv[optind++]);
2453 read_symbols_from_files(files_source);
2455 for (mod = modules; mod; mod = mod->next) {
2463 for (mod = modules; mod; mod = mod->next) {
2464 char fname[PATH_MAX];
2471 add_header(&buf, mod);
2472 add_intree_flag(&buf, !external_module);
2473 add_staging_flag(&buf, mod->name);
2474 err |= add_versions(&buf, mod);
2475 add_depends(&buf, mod, modules);
2476 add_moddevtable(&buf, mod);
2477 add_srcversion(&buf, mod);
2479 sprintf(fname, "%s.mod.c", mod->name);
2480 write_if_changed(&buf, fname);
2483 write_dump(dump_write);
2484 if (sec_mismatch_count) {
2485 if (!sec_mismatch_verbose) {
2486 warn("modpost: Found %d section mismatch(es).\n"
2487 "To see full details build your kernel with:\n"
2488 "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n",
2489 sec_mismatch_count);
2491 if (sec_mismatch_fatal) {
2492 fatal("modpost: Section mismatches detected.\n"
2493 "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");