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 */
837 ".cmem*", /* EZchip */
838 ".fmt_slot*", /* EZchip */
844 * This is used to find sections missing the SHF_ALLOC flag.
845 * The cause of this is often a section specified in assembler
846 * without "ax" / "aw".
848 static void check_section(const char *modname, struct elf_info *elf,
851 const char *sec = sech_name(elf, sechdr);
853 if (sechdr->sh_type == SHT_PROGBITS &&
854 !(sechdr->sh_flags & SHF_ALLOC) &&
855 !match(sec, section_white_list)) {
856 warn("%s (%s): unexpected non-allocatable section.\n"
857 "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
858 "Note that for example <linux/init.h> contains\n"
859 "section definitions for use in .S files.\n\n",
866 #define ALL_INIT_DATA_SECTIONS \
867 ".init.setup", ".init.rodata", ".meminit.rodata", \
868 ".init.data", ".meminit.data"
869 #define ALL_EXIT_DATA_SECTIONS \
870 ".exit.data", ".memexit.data"
872 #define ALL_INIT_TEXT_SECTIONS \
873 ".init.text", ".meminit.text"
874 #define ALL_EXIT_TEXT_SECTIONS \
875 ".exit.text", ".memexit.text"
877 #define ALL_PCI_INIT_SECTIONS \
878 ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
879 ".pci_fixup_enable", ".pci_fixup_resume", \
880 ".pci_fixup_resume_early", ".pci_fixup_suspend"
882 #define ALL_XXXINIT_SECTIONS MEM_INIT_SECTIONS
883 #define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS
885 #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
886 #define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
888 #define DATA_SECTIONS ".data", ".data.rel"
889 #define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \
891 #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
892 ".fixup", ".entry.text", ".exception.text", ".text.*", \
895 #define INIT_SECTIONS ".init.*"
896 #define MEM_INIT_SECTIONS ".meminit.*"
898 #define EXIT_SECTIONS ".exit.*"
899 #define MEM_EXIT_SECTIONS ".memexit.*"
901 #define ALL_TEXT_SECTIONS ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \
902 TEXT_SECTIONS, OTHER_TEXT_SECTIONS
904 /* init data sections */
905 static const char *const init_data_sections[] =
906 { ALL_INIT_DATA_SECTIONS, NULL };
908 /* all init sections */
909 static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL };
911 /* All init and exit sections (code + data) */
912 static const char *const init_exit_sections[] =
913 {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
915 /* all text sections */
916 static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL };
919 static const char *const data_sections[] = { DATA_SECTIONS, NULL };
922 /* symbols in .data that may refer to init/exit sections */
923 #define DEFAULT_SYMBOL_WHITE_LIST \
925 "*_template", /* scsi uses *_template a lot */ \
926 "*_timer", /* arm uses ops structures named _timer a lot */ \
927 "*_sht", /* scsi also used *_sht to some extent */ \
933 static const char *const head_sections[] = { ".head.text*", NULL };
934 static const char *const linker_symbols[] =
935 { "__init_begin", "_sinittext", "_einittext", NULL };
936 static const char *const optim_symbols[] = { "*.constprop.*", NULL };
943 XXXINIT_TO_SOME_INIT,
944 XXXEXIT_TO_SOME_EXIT,
945 ANY_INIT_TO_ANY_EXIT,
946 ANY_EXIT_TO_ANY_INIT,
952 * Describe how to match sections on different criterias:
954 * @fromsec: Array of sections to be matched.
956 * @bad_tosec: Relocations applied to a section in @fromsec to a section in
957 * this array is forbidden (black-list). Can be empty.
959 * @good_tosec: Relocations applied to a section in @fromsec must be
960 * targetting sections in this array (white-list). Can be empty.
962 * @mismatch: Type of mismatch.
964 * @symbol_white_list: Do not match a relocation to a symbol in this list
965 * even if it is targetting a section in @bad_to_sec.
967 * @handler: Specific handler to call when a match is found. If NULL,
968 * default_mismatch_handler() will be called.
971 struct sectioncheck {
972 const char *fromsec[20];
973 const char *bad_tosec[20];
974 const char *good_tosec[20];
975 enum mismatch mismatch;
976 const char *symbol_white_list[20];
977 void (*handler)(const char *modname, struct elf_info *elf,
978 const struct sectioncheck* const mismatch,
979 Elf_Rela *r, Elf_Sym *sym, const char *fromsec);
983 static void extable_mismatch_handler(const char *modname, struct elf_info *elf,
984 const struct sectioncheck* const mismatch,
985 Elf_Rela *r, Elf_Sym *sym,
986 const char *fromsec);
988 static const struct sectioncheck sectioncheck[] = {
989 /* Do not reference init/exit code/data from
990 * normal code and data
993 .fromsec = { TEXT_SECTIONS, NULL },
994 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
995 .mismatch = TEXT_TO_ANY_INIT,
996 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
999 .fromsec = { DATA_SECTIONS, NULL },
1000 .bad_tosec = { ALL_XXXINIT_SECTIONS, NULL },
1001 .mismatch = DATA_TO_ANY_INIT,
1002 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1005 .fromsec = { DATA_SECTIONS, NULL },
1006 .bad_tosec = { INIT_SECTIONS, NULL },
1007 .mismatch = DATA_TO_ANY_INIT,
1008 .symbol_white_list = {
1009 "*_template", "*_timer", "*_sht", "*_ops",
1010 "*_probe", "*_probe_one", "*_console", NULL
1014 .fromsec = { TEXT_SECTIONS, NULL },
1015 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1016 .mismatch = TEXT_TO_ANY_EXIT,
1017 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1020 .fromsec = { DATA_SECTIONS, NULL },
1021 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1022 .mismatch = DATA_TO_ANY_EXIT,
1023 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1025 /* Do not reference init code/data from meminit code/data */
1027 .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
1028 .bad_tosec = { INIT_SECTIONS, NULL },
1029 .mismatch = XXXINIT_TO_SOME_INIT,
1030 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1032 /* Do not reference exit code/data from memexit code/data */
1034 .fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
1035 .bad_tosec = { EXIT_SECTIONS, NULL },
1036 .mismatch = XXXEXIT_TO_SOME_EXIT,
1037 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1039 /* Do not use exit code/data from init code */
1041 .fromsec = { ALL_INIT_SECTIONS, NULL },
1042 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1043 .mismatch = ANY_INIT_TO_ANY_EXIT,
1044 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1046 /* Do not use init code/data from exit code */
1048 .fromsec = { ALL_EXIT_SECTIONS, NULL },
1049 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1050 .mismatch = ANY_EXIT_TO_ANY_INIT,
1051 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1054 .fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
1055 .bad_tosec = { INIT_SECTIONS, NULL },
1056 .mismatch = ANY_INIT_TO_ANY_EXIT,
1057 .symbol_white_list = { NULL },
1059 /* Do not export init/exit functions or data */
1061 .fromsec = { "__ksymtab*", NULL },
1062 .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
1063 .mismatch = EXPORT_TO_INIT_EXIT,
1064 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1067 .fromsec = { "__ex_table", NULL },
1068 /* If you're adding any new black-listed sections in here, consider
1069 * adding a special 'printer' for them in scripts/check_extable.
1071 .bad_tosec = { ".altinstr_replacement", NULL },
1072 .good_tosec = {ALL_TEXT_SECTIONS , NULL},
1073 .mismatch = EXTABLE_TO_NON_TEXT,
1074 .handler = extable_mismatch_handler,
1078 static const struct sectioncheck *section_mismatch(
1079 const char *fromsec, const char *tosec)
1082 int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
1083 const struct sectioncheck *check = §ioncheck[0];
1086 * The target section could be the SHT_NUL section when we're
1087 * handling relocations to un-resolved symbols, trying to match it
1088 * doesn't make much sense and causes build failures on parisc and
1089 * mn10300 architectures.
1094 for (i = 0; i < elems; i++) {
1095 if (match(fromsec, check->fromsec)) {
1096 if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
1098 if (check->good_tosec[0] && !match(tosec, check->good_tosec))
1107 * Whitelist to allow certain references to pass with no warning.
1110 * If a module parameter is declared __initdata and permissions=0
1111 * then this is legal despite the warning generated.
1112 * We cannot see value of permissions here, so just ignore
1114 * The pattern is identified by:
1115 * tosec = .init.data
1120 * module_param_call() ops can refer to __init set function if permissions=0
1121 * The pattern is identified by:
1122 * tosec = .init.text
1124 * atsym = __param_ops_*
1127 * Many drivers utilise a *driver container with references to
1128 * add, remove, probe functions etc.
1129 * the pattern is identified by:
1130 * tosec = init or exit section
1131 * fromsec = data section
1132 * atsym = *driver, *_template, *_sht, *_ops, *_probe,
1133 * *probe_one, *_console, *_timer
1136 * Whitelist all references from .head.text to any init section
1139 * Some symbols belong to init section but still it is ok to reference
1140 * these from non-init sections as these symbols don't have any memory
1141 * allocated for them and symbol address and value are same. So even
1142 * if init section is freed, its ok to reference those symbols.
1143 * For ex. symbols marking the init section boundaries.
1144 * This pattern is identified by
1145 * refsymname = __init_begin, _sinittext, _einittext
1148 * GCC may optimize static inlines when fed constant arg(s) resulting
1149 * in functions like cpumask_empty() -- generating an associated symbol
1150 * cpumask_empty.constprop.3 that appears in the audit. If the const that
1151 * is passed in comes from __init, like say nmi_ipi_mask, we get a
1152 * meaningless section warning. May need to add isra symbols too...
1153 * This pattern is identified by
1154 * tosec = init section
1155 * fromsec = text section
1156 * refsymname = *.constprop.*
1159 static int secref_whitelist(const struct sectioncheck *mismatch,
1160 const char *fromsec, const char *fromsym,
1161 const char *tosec, const char *tosym)
1163 /* Check for pattern 1 */
1164 if (match(tosec, init_data_sections) &&
1165 match(fromsec, data_sections) &&
1166 (strncmp(fromsym, "__param", strlen("__param")) == 0))
1169 /* Check for pattern 1a */
1170 if (strcmp(tosec, ".init.text") == 0 &&
1171 match(fromsec, data_sections) &&
1172 (strncmp(fromsym, "__param_ops_", strlen("__param_ops_")) == 0))
1175 /* Check for pattern 2 */
1176 if (match(tosec, init_exit_sections) &&
1177 match(fromsec, data_sections) &&
1178 match(fromsym, mismatch->symbol_white_list))
1181 /* Check for pattern 3 */
1182 if (match(fromsec, head_sections) &&
1183 match(tosec, init_sections))
1186 /* Check for pattern 4 */
1187 if (match(tosym, linker_symbols))
1190 /* Check for pattern 5 */
1191 if (match(fromsec, text_sections) &&
1192 match(tosec, init_sections) &&
1193 match(fromsym, optim_symbols))
1200 * Find symbol based on relocation record info.
1201 * In some cases the symbol supplied is a valid symbol so
1202 * return refsym. If st_name != 0 we assume this is a valid symbol.
1203 * In other cases the symbol needs to be looked up in the symbol table
1204 * based on section and address.
1206 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
1210 Elf_Sym *near = NULL;
1211 Elf64_Sword distance = 20;
1213 unsigned int relsym_secindex;
1215 if (relsym->st_name != 0)
1218 relsym_secindex = get_secindex(elf, relsym);
1219 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1220 if (get_secindex(elf, sym) != relsym_secindex)
1222 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
1224 if (sym->st_value == addr)
1226 /* Find a symbol nearby - addr are maybe negative */
1227 d = sym->st_value - addr;
1229 d = addr - sym->st_value;
1235 /* We need a close match */
1242 static inline int is_arm_mapping_symbol(const char *str)
1244 return str[0] == '$' && strchr("axtd", str[1])
1245 && (str[2] == '\0' || str[2] == '.');
1249 * If there's no name there, ignore it; likewise, ignore it if it's
1250 * one of the magic symbols emitted used by current ARM tools.
1252 * Otherwise if find_symbols_between() returns those symbols, they'll
1253 * fail the whitelist tests and cause lots of false alarms ... fixable
1254 * only by merging __exit and __init sections into __text, bloating
1255 * the kernel (which is especially evil on embedded platforms).
1257 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1259 const char *name = elf->strtab + sym->st_name;
1261 if (!name || !strlen(name))
1263 return !is_arm_mapping_symbol(name);
1267 * Find symbols before or equal addr and after addr - in the section sec.
1268 * If we find two symbols with equal offset prefer one with a valid name.
1269 * The ELF format may have a better way to detect what type of symbol
1270 * it is, but this works for now.
1272 static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1276 Elf_Sym *near = NULL;
1277 Elf_Addr distance = ~0;
1279 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1282 if (is_shndx_special(sym->st_shndx))
1284 symsec = sec_name(elf, get_secindex(elf, sym));
1285 if (strcmp(symsec, sec) != 0)
1287 if (!is_valid_name(elf, sym))
1289 if (sym->st_value <= addr) {
1290 if ((addr - sym->st_value) < distance) {
1291 distance = addr - sym->st_value;
1293 } else if ((addr - sym->st_value) == distance) {
1302 * Convert a section name to the function/data attribute
1303 * .init.text => __init
1304 * .memexitconst => __memconst
1307 * The memory of returned value has been allocated on a heap. The user of this
1308 * method should free it after usage.
1310 static char *sec2annotation(const char *s)
1312 if (match(s, init_exit_sections)) {
1313 char *p = malloc(20);
1320 while (*s && *s != '.')
1325 if (strstr(s, "rodata") != NULL)
1326 strcat(p, "const ");
1327 else if (strstr(s, "data") != NULL)
1337 static int is_function(Elf_Sym *sym)
1340 return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1345 static void print_section_list(const char * const list[20])
1347 const char *const *s = list;
1350 fprintf(stderr, "%s", *s);
1353 fprintf(stderr, ", ");
1355 fprintf(stderr, "\n");
1358 static inline void get_pretty_name(int is_func, const char** name, const char** name_p)
1361 case 0: *name = "variable"; *name_p = ""; break;
1362 case 1: *name = "function"; *name_p = "()"; break;
1363 default: *name = "(unknown reference)"; *name_p = ""; break;
1368 * Print a warning about a section mismatch.
1369 * Try to find symbols near it so user can find it.
1370 * Check whitelist before warning - it may be a false positive.
1372 static void report_sec_mismatch(const char *modname,
1373 const struct sectioncheck *mismatch,
1374 const char *fromsec,
1375 unsigned long long fromaddr,
1376 const char *fromsym,
1378 const char *tosec, const char *tosym,
1381 const char *from, *from_p;
1382 const char *to, *to_p;
1386 sec_mismatch_count++;
1387 if (!sec_mismatch_verbose)
1390 get_pretty_name(from_is_func, &from, &from_p);
1391 get_pretty_name(to_is_func, &to, &to_p);
1393 warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1394 "to the %s %s:%s%s\n",
1395 modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1398 switch (mismatch->mismatch) {
1399 case TEXT_TO_ANY_INIT:
1400 prl_from = sec2annotation(fromsec);
1401 prl_to = sec2annotation(tosec);
1403 "The function %s%s() references\n"
1405 "This is often because %s lacks a %s\n"
1406 "annotation or the annotation of %s is wrong.\n",
1408 to, prl_to, tosym, to_p,
1409 fromsym, prl_to, tosym);
1413 case DATA_TO_ANY_INIT: {
1414 prl_to = sec2annotation(tosec);
1416 "The variable %s references\n"
1418 "If the reference is valid then annotate the\n"
1419 "variable with __init* or __refdata (see linux/init.h) "
1420 "or name the variable:\n",
1421 fromsym, to, prl_to, tosym, to_p);
1422 print_section_list(mismatch->symbol_white_list);
1426 case TEXT_TO_ANY_EXIT:
1427 prl_to = sec2annotation(tosec);
1429 "The function %s() references a %s in an exit section.\n"
1430 "Often the %s %s%s has valid usage outside the exit section\n"
1431 "and the fix is to remove the %sannotation of %s.\n",
1432 fromsym, to, to, tosym, to_p, prl_to, tosym);
1435 case DATA_TO_ANY_EXIT: {
1436 prl_to = sec2annotation(tosec);
1438 "The variable %s references\n"
1440 "If the reference is valid then annotate the\n"
1441 "variable with __exit* (see linux/init.h) or "
1442 "name the variable:\n",
1443 fromsym, to, prl_to, tosym, to_p);
1444 print_section_list(mismatch->symbol_white_list);
1448 case XXXINIT_TO_SOME_INIT:
1449 case XXXEXIT_TO_SOME_EXIT:
1450 prl_from = sec2annotation(fromsec);
1451 prl_to = sec2annotation(tosec);
1453 "The %s %s%s%s references\n"
1455 "If %s is only used by %s then\n"
1456 "annotate %s with a matching annotation.\n",
1457 from, prl_from, fromsym, from_p,
1458 to, prl_to, tosym, to_p,
1459 tosym, fromsym, tosym);
1463 case ANY_INIT_TO_ANY_EXIT:
1464 prl_from = sec2annotation(fromsec);
1465 prl_to = sec2annotation(tosec);
1467 "The %s %s%s%s references\n"
1469 "This is often seen when error handling "
1470 "in the init function\n"
1471 "uses functionality in the exit path.\n"
1472 "The fix is often to remove the %sannotation of\n"
1473 "%s%s so it may be used outside an exit section.\n",
1474 from, prl_from, fromsym, from_p,
1475 to, prl_to, tosym, to_p,
1476 prl_to, tosym, to_p);
1480 case ANY_EXIT_TO_ANY_INIT:
1481 prl_from = sec2annotation(fromsec);
1482 prl_to = sec2annotation(tosec);
1484 "The %s %s%s%s references\n"
1486 "This is often seen when error handling "
1487 "in the exit function\n"
1488 "uses functionality in the init path.\n"
1489 "The fix is often to remove the %sannotation of\n"
1490 "%s%s so it may be used outside an init section.\n",
1491 from, prl_from, fromsym, from_p,
1492 to, prl_to, tosym, to_p,
1493 prl_to, tosym, to_p);
1497 case EXPORT_TO_INIT_EXIT:
1498 prl_to = sec2annotation(tosec);
1500 "The symbol %s is exported and annotated %s\n"
1501 "Fix this by removing the %sannotation of %s "
1502 "or drop the export.\n",
1503 tosym, prl_to, prl_to, tosym);
1506 case EXTABLE_TO_NON_TEXT:
1507 fatal("There's a special handler for this mismatch type, "
1508 "we should never get here.");
1511 fprintf(stderr, "\n");
1514 static void default_mismatch_handler(const char *modname, struct elf_info *elf,
1515 const struct sectioncheck* const mismatch,
1516 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1522 const char *fromsym;
1524 from = find_elf_symbol2(elf, r->r_offset, fromsec);
1525 fromsym = sym_name(elf, from);
1527 if (!strncmp(fromsym, "reference___initcall",
1528 sizeof("reference___initcall")-1))
1531 tosec = sec_name(elf, get_secindex(elf, sym));
1532 to = find_elf_symbol(elf, r->r_addend, sym);
1533 tosym = sym_name(elf, to);
1535 /* check whitelist - we may ignore it */
1536 if (secref_whitelist(mismatch,
1537 fromsec, fromsym, tosec, tosym)) {
1538 report_sec_mismatch(modname, mismatch,
1539 fromsec, r->r_offset, fromsym,
1540 is_function(from), tosec, tosym,
1545 static int is_executable_section(struct elf_info* elf, unsigned int section_index)
1547 if (section_index > elf->num_sections)
1548 fatal("section_index is outside elf->num_sections!\n");
1550 return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR);
1554 * We rely on a gross hack in section_rel[a]() calling find_extable_entry_size()
1555 * to know the sizeof(struct exception_table_entry) for the target architecture.
1557 static unsigned int extable_entry_size = 0;
1558 static void find_extable_entry_size(const char* const sec, const Elf_Rela* r)
1561 * If we're currently checking the second relocation within __ex_table,
1562 * that relocation offset tells us the offsetof(struct
1563 * exception_table_entry, fixup) which is equal to sizeof(struct
1564 * exception_table_entry) divided by two. We use that to our advantage
1565 * since there's no portable way to get that size as every architecture
1566 * seems to go with different sized types. Not pretty but better than
1567 * hard-coding the size for every architecture..
1569 if (!extable_entry_size)
1570 extable_entry_size = r->r_offset * 2;
1573 static inline bool is_extable_fault_address(Elf_Rela *r)
1576 * extable_entry_size is only discovered after we've handled the
1577 * _second_ relocation in __ex_table, so only abort when we're not
1578 * handling the first reloc and extable_entry_size is zero.
1580 if (r->r_offset && extable_entry_size == 0)
1581 fatal("extable_entry size hasn't been discovered!\n");
1583 return ((r->r_offset == 0) ||
1584 (r->r_offset % extable_entry_size == 0));
1587 #define is_second_extable_reloc(Start, Cur, Sec) \
1588 (((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0))
1590 static void report_extable_warnings(const char* modname, struct elf_info* elf,
1591 const struct sectioncheck* const mismatch,
1592 Elf_Rela* r, Elf_Sym* sym,
1593 const char* fromsec, const char* tosec)
1595 Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec);
1596 const char* fromsym_name = sym_name(elf, fromsym);
1597 Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym);
1598 const char* tosym_name = sym_name(elf, tosym);
1599 const char* from_pretty_name;
1600 const char* from_pretty_name_p;
1601 const char* to_pretty_name;
1602 const char* to_pretty_name_p;
1604 get_pretty_name(is_function(fromsym),
1605 &from_pretty_name, &from_pretty_name_p);
1606 get_pretty_name(is_function(tosym),
1607 &to_pretty_name, &to_pretty_name_p);
1609 warn("%s(%s+0x%lx): Section mismatch in reference"
1610 " from the %s %s%s to the %s %s:%s%s\n",
1611 modname, fromsec, (long)r->r_offset, from_pretty_name,
1612 fromsym_name, from_pretty_name_p,
1613 to_pretty_name, tosec, tosym_name, to_pretty_name_p);
1615 if (!match(tosec, mismatch->bad_tosec) &&
1616 is_executable_section(elf, get_secindex(elf, sym)))
1618 "The relocation at %s+0x%lx references\n"
1619 "section \"%s\" which is not in the list of\n"
1620 "authorized sections. If you're adding a new section\n"
1621 "and/or if this reference is valid, add \"%s\" to the\n"
1622 "list of authorized sections to jump to on fault.\n"
1623 "This can be achieved by adding \"%s\" to \n"
1624 "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
1625 fromsec, (long)r->r_offset, tosec, tosec, tosec);
1628 static void extable_mismatch_handler(const char* modname, struct elf_info *elf,
1629 const struct sectioncheck* const mismatch,
1630 Elf_Rela* r, Elf_Sym* sym,
1631 const char *fromsec)
1633 const char* tosec = sec_name(elf, get_secindex(elf, sym));
1635 sec_mismatch_count++;
1637 if (sec_mismatch_verbose)
1638 report_extable_warnings(modname, elf, mismatch, r, sym,
1641 if (match(tosec, mismatch->bad_tosec))
1642 fatal("The relocation at %s+0x%lx references\n"
1643 "section \"%s\" which is black-listed.\n"
1644 "Something is seriously wrong and should be fixed.\n"
1645 "You might get more information about where this is\n"
1646 "coming from by using scripts/check_extable.sh %s\n",
1647 fromsec, (long)r->r_offset, tosec, modname);
1648 else if (!is_executable_section(elf, get_secindex(elf, sym))) {
1649 if (is_extable_fault_address(r))
1650 fatal("The relocation at %s+0x%lx references\n"
1651 "section \"%s\" which is not executable, IOW\n"
1652 "it is not possible for the kernel to fault\n"
1653 "at that address. Something is seriously wrong\n"
1654 "and should be fixed.\n",
1655 fromsec, (long)r->r_offset, tosec);
1657 fatal("The relocation at %s+0x%lx references\n"
1658 "section \"%s\" which is not executable, IOW\n"
1659 "the kernel will fault if it ever tries to\n"
1660 "jump to it. Something is seriously wrong\n"
1661 "and should be fixed.\n",
1662 fromsec, (long)r->r_offset, tosec);
1666 static void check_section_mismatch(const char *modname, struct elf_info *elf,
1667 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1669 const char *tosec = sec_name(elf, get_secindex(elf, sym));;
1670 const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec);
1673 if (mismatch->handler)
1674 mismatch->handler(modname, elf, mismatch,
1677 default_mismatch_handler(modname, elf, mismatch,
1682 static unsigned int *reloc_location(struct elf_info *elf,
1683 Elf_Shdr *sechdr, Elf_Rela *r)
1685 Elf_Shdr *sechdrs = elf->sechdrs;
1686 int section = sechdr->sh_info;
1688 return (void *)elf->hdr + sechdrs[section].sh_offset +
1692 static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1694 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1695 unsigned int *location = reloc_location(elf, sechdr, r);
1699 r->r_addend = TO_NATIVE(*location);
1702 r->r_addend = TO_NATIVE(*location) + 4;
1703 /* For CONFIG_RELOCATABLE=y */
1704 if (elf->hdr->e_type == ET_EXEC)
1705 r->r_addend += r->r_offset;
1712 #define R_ARM_CALL 28
1714 #ifndef R_ARM_JUMP24
1715 #define R_ARM_JUMP24 29
1718 #ifndef R_ARM_THM_CALL
1719 #define R_ARM_THM_CALL 10
1721 #ifndef R_ARM_THM_JUMP24
1722 #define R_ARM_THM_JUMP24 30
1724 #ifndef R_ARM_THM_JUMP19
1725 #define R_ARM_THM_JUMP19 51
1728 static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1730 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1734 /* From ARM ABI: (S + A) | T */
1735 r->r_addend = (int)(long)
1736 (elf->symtab_start + ELF_R_SYM(r->r_info));
1741 case R_ARM_THM_CALL:
1742 case R_ARM_THM_JUMP24:
1743 case R_ARM_THM_JUMP19:
1744 /* From ARM ABI: ((S + A) | T) - P */
1745 r->r_addend = (int)(long)(elf->hdr +
1747 (r->r_offset - sechdr->sh_addr));
1755 static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1757 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1758 unsigned int *location = reloc_location(elf, sechdr, r);
1761 if (r_typ == R_MIPS_HI16)
1762 return 1; /* skip this */
1763 inst = TO_NATIVE(*location);
1766 r->r_addend = inst & 0xffff;
1769 r->r_addend = (inst & 0x03ffffff) << 2;
1778 static void section_rela(const char *modname, struct elf_info *elf,
1785 const char *fromsec;
1787 Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1788 Elf_Rela *stop = (void *)start + sechdr->sh_size;
1790 fromsec = sech_name(elf, sechdr);
1791 fromsec += strlen(".rela");
1792 /* if from section (name) is know good then skip it */
1793 if (match(fromsec, section_white_list))
1796 for (rela = start; rela < stop; rela++) {
1797 r.r_offset = TO_NATIVE(rela->r_offset);
1798 #if KERNEL_ELFCLASS == ELFCLASS64
1799 if (elf->hdr->e_machine == EM_MIPS) {
1801 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1802 r_sym = TO_NATIVE(r_sym);
1803 r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1804 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1806 r.r_info = TO_NATIVE(rela->r_info);
1807 r_sym = ELF_R_SYM(r.r_info);
1810 r.r_info = TO_NATIVE(rela->r_info);
1811 r_sym = ELF_R_SYM(r.r_info);
1813 r.r_addend = TO_NATIVE(rela->r_addend);
1814 sym = elf->symtab_start + r_sym;
1815 /* Skip special sections */
1816 if (is_shndx_special(sym->st_shndx))
1818 if (is_second_extable_reloc(start, rela, fromsec))
1819 find_extable_entry_size(fromsec, &r);
1820 check_section_mismatch(modname, elf, &r, sym, fromsec);
1824 static void section_rel(const char *modname, struct elf_info *elf,
1831 const char *fromsec;
1833 Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1834 Elf_Rel *stop = (void *)start + sechdr->sh_size;
1836 fromsec = sech_name(elf, sechdr);
1837 fromsec += strlen(".rel");
1838 /* if from section (name) is know good then skip it */
1839 if (match(fromsec, section_white_list))
1842 for (rel = start; rel < stop; rel++) {
1843 r.r_offset = TO_NATIVE(rel->r_offset);
1844 #if KERNEL_ELFCLASS == ELFCLASS64
1845 if (elf->hdr->e_machine == EM_MIPS) {
1847 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1848 r_sym = TO_NATIVE(r_sym);
1849 r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1850 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1852 r.r_info = TO_NATIVE(rel->r_info);
1853 r_sym = ELF_R_SYM(r.r_info);
1856 r.r_info = TO_NATIVE(rel->r_info);
1857 r_sym = ELF_R_SYM(r.r_info);
1860 switch (elf->hdr->e_machine) {
1862 if (addend_386_rel(elf, sechdr, &r))
1866 if (addend_arm_rel(elf, sechdr, &r))
1870 if (addend_mips_rel(elf, sechdr, &r))
1874 sym = elf->symtab_start + r_sym;
1875 /* Skip special sections */
1876 if (is_shndx_special(sym->st_shndx))
1878 if (is_second_extable_reloc(start, rel, fromsec))
1879 find_extable_entry_size(fromsec, &r);
1880 check_section_mismatch(modname, elf, &r, sym, fromsec);
1885 * A module includes a number of sections that are discarded
1886 * either when loaded or when used as built-in.
1887 * For loaded modules all functions marked __init and all data
1888 * marked __initdata will be discarded when the module has been initialized.
1889 * Likewise for modules used built-in the sections marked __exit
1890 * are discarded because __exit marked function are supposed to be called
1891 * only when a module is unloaded which never happens for built-in modules.
1892 * The check_sec_ref() function traverses all relocation records
1893 * to find all references to a section that reference a section that will
1894 * be discarded and warns about it.
1896 static void check_sec_ref(struct module *mod, const char *modname,
1897 struct elf_info *elf)
1900 Elf_Shdr *sechdrs = elf->sechdrs;
1902 /* Walk through all sections */
1903 for (i = 0; i < elf->num_sections; i++) {
1904 check_section(modname, elf, &elf->sechdrs[i]);
1905 /* We want to process only relocation sections and not .init */
1906 if (sechdrs[i].sh_type == SHT_RELA)
1907 section_rela(modname, elf, &elf->sechdrs[i]);
1908 else if (sechdrs[i].sh_type == SHT_REL)
1909 section_rel(modname, elf, &elf->sechdrs[i]);
1913 static char *remove_dot(char *s)
1915 size_t n = strcspn(s, ".");
1918 size_t m = strspn(s + n + 1, "0123456789");
1919 if (m && (s[n + m] == '.' || s[n + m] == 0))
1925 static void read_symbols(char *modname)
1927 const char *symname;
1931 struct elf_info info = { };
1934 if (!parse_elf(&info, modname))
1937 mod = new_module(modname);
1939 /* When there's no vmlinux, don't print warnings about
1940 * unresolved symbols (since there'll be too many ;) */
1941 if (is_vmlinux(modname)) {
1946 license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1947 if (info.modinfo && !license && !is_vmlinux(modname))
1948 warn("modpost: missing MODULE_LICENSE() in %s\n"
1949 "see include/linux/module.h for "
1950 "more information\n", modname);
1952 if (license_is_gpl_compatible(license))
1953 mod->gpl_compatible = 1;
1955 mod->gpl_compatible = 0;
1958 license = get_next_modinfo(info.modinfo, info.modinfo_len,
1959 "license", license);
1962 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1963 symname = remove_dot(info.strtab + sym->st_name);
1965 handle_modversions(mod, &info, sym, symname);
1966 handle_moddevtable(mod, &info, sym, symname);
1968 if (!is_vmlinux(modname) ||
1969 (is_vmlinux(modname) && vmlinux_section_warnings))
1970 check_sec_ref(mod, modname, &info);
1972 version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1974 maybe_frob_rcs_version(modname, version, info.modinfo,
1975 version - (char *)info.hdr);
1976 if (version || (all_versions && !is_vmlinux(modname)))
1977 get_src_version(modname, mod->srcversion,
1978 sizeof(mod->srcversion)-1);
1980 parse_elf_finish(&info);
1982 /* Our trick to get versioning for module struct etc. - it's
1983 * never passed as an argument to an exported function, so
1984 * the automatic versioning doesn't pick it up, but it's really
1985 * important anyhow */
1987 mod->unres = alloc_symbol("module_layout", 0, mod->unres);
1990 static void read_symbols_from_files(const char *filename)
1993 char fname[PATH_MAX];
1995 if (strcmp(filename, "-") != 0) {
1996 in = fopen(filename, "r");
1998 fatal("Can't open filenames file %s: %m", filename);
2001 while (fgets(fname, PATH_MAX, in) != NULL) {
2002 if (strends(fname, "\n"))
2003 fname[strlen(fname)-1] = '\0';
2004 read_symbols(fname);
2013 /* We first write the generated file into memory using the
2014 * following helper, then compare to the file on disk and
2015 * only update the later if anything changed */
2017 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
2018 const char *fmt, ...)
2025 len = vsnprintf(tmp, SZ, fmt, ap);
2026 buf_write(buf, tmp, len);
2030 void buf_write(struct buffer *buf, const char *s, int len)
2032 if (buf->size - buf->pos < len) {
2033 buf->size += len + SZ;
2034 buf->p = realloc(buf->p, buf->size);
2036 strncpy(buf->p + buf->pos, s, len);
2040 static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
2042 const char *e = is_vmlinux(m) ?"":".ko";
2046 fatal("modpost: GPL-incompatible module %s%s "
2047 "uses GPL-only symbol '%s'\n", m, e, s);
2049 case export_unused_gpl:
2050 fatal("modpost: GPL-incompatible module %s%s "
2051 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
2053 case export_gpl_future:
2054 warn("modpost: GPL-incompatible module %s%s "
2055 "uses future GPL-only symbol '%s'\n", m, e, s);
2059 case export_unknown:
2065 static void check_for_unused(enum export exp, const char *m, const char *s)
2067 const char *e = is_vmlinux(m) ?"":".ko";
2071 case export_unused_gpl:
2072 warn("modpost: module %s%s "
2073 "uses symbol '%s' marked UNUSED\n", m, e, s);
2081 static void check_exports(struct module *mod)
2083 struct symbol *s, *exp;
2085 for (s = mod->unres; s; s = s->next) {
2086 const char *basename;
2087 exp = find_symbol(s->name);
2088 if (!exp || exp->module == mod)
2090 basename = strrchr(mod->name, '/');
2094 basename = mod->name;
2095 if (!mod->gpl_compatible)
2096 check_for_gpl_usage(exp->export, basename, exp->name);
2097 check_for_unused(exp->export, basename, exp->name);
2102 * Header for the generated file
2104 static void add_header(struct buffer *b, struct module *mod)
2106 buf_printf(b, "#include <linux/module.h>\n");
2107 buf_printf(b, "#include <linux/vermagic.h>\n");
2108 buf_printf(b, "#include <linux/compiler.h>\n");
2109 buf_printf(b, "\n");
2110 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
2111 buf_printf(b, "\n");
2112 buf_printf(b, "__visible struct module __this_module\n");
2113 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
2114 buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
2116 buf_printf(b, "\t.init = init_module,\n");
2117 if (mod->has_cleanup)
2118 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
2119 "\t.exit = cleanup_module,\n"
2121 buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
2122 buf_printf(b, "};\n");
2125 static void add_intree_flag(struct buffer *b, int is_intree)
2128 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
2131 static void add_staging_flag(struct buffer *b, const char *name)
2133 static const char *staging_dir = "drivers/staging";
2135 if (strncmp(staging_dir, name, strlen(staging_dir)) == 0)
2136 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
2139 /* In kernel, this size is defined in linux/module.h;
2140 * here we use Elf_Addr instead of long for covering cross-compile
2142 #define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
2145 * Record CRCs for unresolved symbols
2147 static int add_versions(struct buffer *b, struct module *mod)
2149 struct symbol *s, *exp;
2152 for (s = mod->unres; s; s = s->next) {
2153 exp = find_symbol(s->name);
2154 if (!exp || exp->module == mod) {
2155 if (have_vmlinux && !s->weak) {
2156 if (warn_unresolved) {
2157 warn("\"%s\" [%s.ko] undefined!\n",
2158 s->name, mod->name);
2160 merror("\"%s\" [%s.ko] undefined!\n",
2161 s->name, mod->name);
2167 s->module = exp->module;
2168 s->crc_valid = exp->crc_valid;
2175 buf_printf(b, "\n");
2176 buf_printf(b, "static const struct modversion_info ____versions[]\n");
2177 buf_printf(b, "__used\n");
2178 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
2180 for (s = mod->unres; s; s = s->next) {
2183 if (!s->crc_valid) {
2184 warn("\"%s\" [%s.ko] has no CRC!\n",
2185 s->name, mod->name);
2188 if (strlen(s->name) >= MODULE_NAME_LEN) {
2189 merror("too long symbol \"%s\" [%s.ko]\n",
2190 s->name, mod->name);
2194 buf_printf(b, "\t{ %#8x, __VMLINUX_SYMBOL_STR(%s) },\n",
2198 buf_printf(b, "};\n");
2203 static void add_depends(struct buffer *b, struct module *mod,
2204 struct module *modules)
2210 for (m = modules; m; m = m->next)
2211 m->seen = is_vmlinux(m->name);
2213 buf_printf(b, "\n");
2214 buf_printf(b, "static const char __module_depends[]\n");
2215 buf_printf(b, "__used\n");
2216 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
2217 buf_printf(b, "\"depends=");
2218 for (s = mod->unres; s; s = s->next) {
2223 if (s->module->seen)
2226 s->module->seen = 1;
2227 p = strrchr(s->module->name, '/');
2231 p = s->module->name;
2232 buf_printf(b, "%s%s", first ? "" : ",", p);
2235 buf_printf(b, "\";\n");
2238 static void add_srcversion(struct buffer *b, struct module *mod)
2240 if (mod->srcversion[0]) {
2241 buf_printf(b, "\n");
2242 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
2247 static void write_if_changed(struct buffer *b, const char *fname)
2253 file = fopen(fname, "r");
2257 if (fstat(fileno(file), &st) < 0)
2260 if (st.st_size != b->pos)
2263 tmp = NOFAIL(malloc(b->pos));
2264 if (fread(tmp, 1, b->pos, file) != b->pos)
2267 if (memcmp(tmp, b->p, b->pos) != 0)
2279 file = fopen(fname, "w");
2284 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
2291 /* parse Module.symvers file. line format:
2292 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
2294 static void read_dump(const char *fname, unsigned int kernel)
2296 unsigned long size, pos = 0;
2297 void *file = grab_file(fname, &size);
2301 /* No symbol versions, silently ignore */
2304 while ((line = get_next_line(&pos, file, size))) {
2305 char *symname, *modname, *d, *export, *end;
2310 if (!(symname = strchr(line, '\t')))
2313 if (!(modname = strchr(symname, '\t')))
2316 if ((export = strchr(modname, '\t')) != NULL)
2318 if (export && ((end = strchr(export, '\t')) != NULL))
2320 crc = strtoul(line, &d, 16);
2321 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2323 mod = find_module(modname);
2325 if (is_vmlinux(modname))
2327 mod = new_module(modname);
2330 s = sym_add_exported(symname, mod, export_no(export));
2333 sym_update_crc(symname, mod, crc, export_no(export));
2335 release_file(file, size);
2338 release_file(file, size);
2339 fatal("parse error in symbol dump file\n");
2342 /* For normal builds always dump all symbols.
2343 * For external modules only dump symbols
2344 * that are not read from kernel Module.symvers.
2346 static int dump_sym(struct symbol *sym)
2348 if (!external_module)
2350 if (sym->vmlinux || sym->kernel)
2355 static void write_dump(const char *fname)
2357 struct buffer buf = { };
2358 struct symbol *symbol;
2361 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
2362 symbol = symbolhash[n];
2364 if (dump_sym(symbol))
2365 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
2366 symbol->crc, symbol->name,
2367 symbol->module->name,
2368 export_str(symbol->export));
2369 symbol = symbol->next;
2372 write_if_changed(&buf, fname);
2375 struct ext_sym_list {
2376 struct ext_sym_list *next;
2380 int main(int argc, char **argv)
2383 struct buffer buf = { };
2384 char *kernel_read = NULL, *module_read = NULL;
2385 char *dump_write = NULL, *files_source = NULL;
2388 struct ext_sym_list *extsym_iter;
2389 struct ext_sym_list *extsym_start = NULL;
2391 while ((opt = getopt(argc, argv, "i:I:e:mnsST:o:awM:K:E")) != -1) {
2394 kernel_read = optarg;
2397 module_read = optarg;
2398 external_module = 1;
2401 external_module = 1;
2403 NOFAIL(malloc(sizeof(*extsym_iter)));
2404 extsym_iter->next = extsym_start;
2405 extsym_iter->file = optarg;
2406 extsym_start = extsym_iter;
2412 ignore_missing_files = 1;
2415 dump_write = optarg;
2421 vmlinux_section_warnings = 0;
2424 sec_mismatch_verbose = 0;
2427 files_source = optarg;
2430 warn_unresolved = 1;
2433 sec_mismatch_fatal = 1;
2441 read_dump(kernel_read, 1);
2443 read_dump(module_read, 0);
2444 while (extsym_start) {
2445 read_dump(extsym_start->file, 0);
2446 extsym_iter = extsym_start->next;
2448 extsym_start = extsym_iter;
2451 while (optind < argc)
2452 read_symbols(argv[optind++]);
2455 read_symbols_from_files(files_source);
2457 for (mod = modules; mod; mod = mod->next) {
2465 for (mod = modules; mod; mod = mod->next) {
2466 char fname[PATH_MAX];
2473 add_header(&buf, mod);
2474 add_intree_flag(&buf, !external_module);
2475 add_staging_flag(&buf, mod->name);
2476 err |= add_versions(&buf, mod);
2477 add_depends(&buf, mod, modules);
2478 add_moddevtable(&buf, mod);
2479 add_srcversion(&buf, mod);
2481 sprintf(fname, "%s.mod.c", mod->name);
2482 write_if_changed(&buf, fname);
2485 write_dump(dump_write);
2486 if (sec_mismatch_count) {
2487 if (!sec_mismatch_verbose) {
2488 warn("modpost: Found %d section mismatch(es).\n"
2489 "To see full details build your kernel with:\n"
2490 "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n",
2491 sec_mismatch_count);
2493 if (sec_mismatch_fatal) {
2494 fatal("modpost: Section mismatches detected.\n"
2495 "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");