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 ||
598 strcmp(symname, ".TOC.") == 0)
600 /* Do not ignore this symbol */
604 #define CRC_PFX VMLINUX_SYMBOL_STR(__crc_)
605 #define KSYMTAB_PFX VMLINUX_SYMBOL_STR(__ksymtab_)
607 static void handle_modversions(struct module *mod, struct elf_info *info,
608 Elf_Sym *sym, const char *symname)
614 if ((!is_vmlinux(mod->name) || mod->is_dot_o) &&
615 strncmp(symname, "__ksymtab", 9) == 0)
616 export = export_from_secname(info, get_secindex(info, sym));
618 export = export_from_sec(info, get_secindex(info, sym));
621 if (strncmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
623 crc = (unsigned int) sym->st_value;
624 sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
628 switch (sym->st_shndx) {
630 if (!strncmp(symname, "__gnu_lto_", sizeof("__gnu_lto_")-1)) {
631 /* Should warn here, but modpost runs before the linker */
633 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
636 /* undefined symbol */
637 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
638 ELF_ST_BIND(sym->st_info) != STB_WEAK)
640 if (ignore_undef_symbol(info, symname))
642 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
643 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
644 /* add compatibility with older glibc */
645 #ifndef STT_SPARC_REGISTER
646 #define STT_SPARC_REGISTER STT_REGISTER
648 if (info->hdr->e_machine == EM_SPARC ||
649 info->hdr->e_machine == EM_SPARCV9) {
650 /* Ignore register directives. */
651 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
653 if (symname[0] == '.') {
654 char *munged = strdup(symname);
656 munged[1] = toupper(munged[1]);
662 #ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX
663 if (symname[0] != '_')
669 const char *e = is_vmlinux(mod->name) ?"":".ko";
670 warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n", symname + strlen(CRC_PFX), mod->name, e);
672 mod->unres = alloc_symbol(symname,
673 ELF_ST_BIND(sym->st_info) == STB_WEAK,
677 /* All exported symbols */
678 if (strncmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
679 sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
682 if (strcmp(symname, VMLINUX_SYMBOL_STR(init_module)) == 0)
684 if (strcmp(symname, VMLINUX_SYMBOL_STR(cleanup_module)) == 0)
685 mod->has_cleanup = 1;
691 * Parse tag=value strings from .modinfo section
693 static char *next_string(char *string, unsigned long *secsize)
695 /* Skip non-zero chars */
698 if ((*secsize)-- <= 1)
702 /* Skip any zero padding. */
705 if ((*secsize)-- <= 1)
711 static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
712 const char *tag, char *info)
715 unsigned int taglen = strlen(tag);
716 unsigned long size = modinfo_len;
719 size -= info - (char *)modinfo;
720 modinfo = next_string(info, &size);
723 for (p = modinfo; p; p = next_string(p, &size)) {
724 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
725 return p + taglen + 1;
730 static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
734 return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
738 * Test if string s ends in string sub
741 static int strrcmp(const char *s, const char *sub)
749 sublen = strlen(sub);
751 if ((slen == 0) || (sublen == 0))
757 return memcmp(s + slen - sublen, sub, sublen);
760 static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
763 return elf->strtab + sym->st_name;
768 static const char *sec_name(struct elf_info *elf, int secindex)
770 Elf_Shdr *sechdrs = elf->sechdrs;
771 return (void *)elf->hdr +
772 elf->sechdrs[elf->secindex_strings].sh_offset +
773 sechdrs[secindex].sh_name;
776 static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr)
778 return (void *)elf->hdr +
779 elf->sechdrs[elf->secindex_strings].sh_offset +
783 /* The pattern is an array of simple patterns.
784 * "foo" will match an exact string equal to "foo"
785 * "*foo" will match a string that ends with "foo"
786 * "foo*" will match a string that begins with "foo"
787 * "*foo*" will match a string that contains "foo"
789 static int match(const char *sym, const char * const pat[])
794 const char *endp = p + strlen(p) - 1;
797 if (*p == '*' && *endp == '*') {
798 char *here, *bare = strndup(p + 1, strlen(p) - 2);
800 here = strstr(sym, bare);
806 else if (*p == '*') {
807 if (strrcmp(sym, p + 1) == 0)
811 else if (*endp == '*') {
812 if (strncmp(sym, p, strlen(p) - 1) == 0)
817 if (strcmp(p, sym) == 0)
825 /* sections that we do not want to do full section mismatch check on */
826 static const char *const section_white_list[] =
830 ".cranges", /* sh64 */
831 ".zdebug*", /* Compressed debug sections. */
832 ".GCC-command-line", /* mn10300 */
833 ".GCC.command.line", /* record-gcc-switches, non mn10300 */
834 ".mdebug*", /* alpha, score, mips etc. */
835 ".pdr", /* alpha, score, mips etc. */
840 ".xt.prop", /* xtensa */
841 ".xt.lit", /* xtensa */
842 ".arcextmap*", /* arc */
843 ".gnu.linkonce.arcext*", /* arc : modules */
844 ".cmem*", /* EZchip */
845 ".fmt_slot*", /* EZchip */
851 * This is used to find sections missing the SHF_ALLOC flag.
852 * The cause of this is often a section specified in assembler
853 * without "ax" / "aw".
855 static void check_section(const char *modname, struct elf_info *elf,
858 const char *sec = sech_name(elf, sechdr);
860 if (sechdr->sh_type == SHT_PROGBITS &&
861 !(sechdr->sh_flags & SHF_ALLOC) &&
862 !match(sec, section_white_list)) {
863 warn("%s (%s): unexpected non-allocatable section.\n"
864 "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
865 "Note that for example <linux/init.h> contains\n"
866 "section definitions for use in .S files.\n\n",
873 #define ALL_INIT_DATA_SECTIONS \
874 ".init.setup", ".init.rodata", ".meminit.rodata", \
875 ".init.data", ".meminit.data"
876 #define ALL_EXIT_DATA_SECTIONS \
877 ".exit.data", ".memexit.data"
879 #define ALL_INIT_TEXT_SECTIONS \
880 ".init.text", ".meminit.text"
881 #define ALL_EXIT_TEXT_SECTIONS \
882 ".exit.text", ".memexit.text"
884 #define ALL_PCI_INIT_SECTIONS \
885 ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
886 ".pci_fixup_enable", ".pci_fixup_resume", \
887 ".pci_fixup_resume_early", ".pci_fixup_suspend"
889 #define ALL_XXXINIT_SECTIONS MEM_INIT_SECTIONS
890 #define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS
892 #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
893 #define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
895 #define DATA_SECTIONS ".data", ".data.rel"
896 #define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \
897 ".kprobes.text", ".cpuidle.text"
898 #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
899 ".fixup", ".entry.text", ".exception.text", ".text.*", \
902 #define INIT_SECTIONS ".init.*"
903 #define MEM_INIT_SECTIONS ".meminit.*"
905 #define EXIT_SECTIONS ".exit.*"
906 #define MEM_EXIT_SECTIONS ".memexit.*"
908 #define ALL_TEXT_SECTIONS ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \
909 TEXT_SECTIONS, OTHER_TEXT_SECTIONS
911 /* init data sections */
912 static const char *const init_data_sections[] =
913 { ALL_INIT_DATA_SECTIONS, NULL };
915 /* all init sections */
916 static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL };
918 /* All init and exit sections (code + data) */
919 static const char *const init_exit_sections[] =
920 {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
922 /* all text sections */
923 static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL };
926 static const char *const data_sections[] = { DATA_SECTIONS, NULL };
929 /* symbols in .data that may refer to init/exit sections */
930 #define DEFAULT_SYMBOL_WHITE_LIST \
932 "*_template", /* scsi uses *_template a lot */ \
933 "*_timer", /* arm uses ops structures named _timer a lot */ \
934 "*_sht", /* scsi also used *_sht to some extent */ \
940 static const char *const head_sections[] = { ".head.text*", NULL };
941 static const char *const linker_symbols[] =
942 { "__init_begin", "_sinittext", "_einittext", NULL };
943 static const char *const optim_symbols[] = { "*.constprop.*", NULL };
950 XXXINIT_TO_SOME_INIT,
951 XXXEXIT_TO_SOME_EXIT,
952 ANY_INIT_TO_ANY_EXIT,
953 ANY_EXIT_TO_ANY_INIT,
959 * Describe how to match sections on different criterias:
961 * @fromsec: Array of sections to be matched.
963 * @bad_tosec: Relocations applied to a section in @fromsec to a section in
964 * this array is forbidden (black-list). Can be empty.
966 * @good_tosec: Relocations applied to a section in @fromsec must be
967 * targetting sections in this array (white-list). Can be empty.
969 * @mismatch: Type of mismatch.
971 * @symbol_white_list: Do not match a relocation to a symbol in this list
972 * even if it is targetting a section in @bad_to_sec.
974 * @handler: Specific handler to call when a match is found. If NULL,
975 * default_mismatch_handler() will be called.
978 struct sectioncheck {
979 const char *fromsec[20];
980 const char *bad_tosec[20];
981 const char *good_tosec[20];
982 enum mismatch mismatch;
983 const char *symbol_white_list[20];
984 void (*handler)(const char *modname, struct elf_info *elf,
985 const struct sectioncheck* const mismatch,
986 Elf_Rela *r, Elf_Sym *sym, const char *fromsec);
990 static void extable_mismatch_handler(const char *modname, struct elf_info *elf,
991 const struct sectioncheck* const mismatch,
992 Elf_Rela *r, Elf_Sym *sym,
993 const char *fromsec);
995 static const struct sectioncheck sectioncheck[] = {
996 /* Do not reference init/exit code/data from
997 * normal code and data
1000 .fromsec = { TEXT_SECTIONS, NULL },
1001 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1002 .mismatch = TEXT_TO_ANY_INIT,
1003 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1006 .fromsec = { DATA_SECTIONS, NULL },
1007 .bad_tosec = { ALL_XXXINIT_SECTIONS, NULL },
1008 .mismatch = DATA_TO_ANY_INIT,
1009 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1012 .fromsec = { DATA_SECTIONS, NULL },
1013 .bad_tosec = { INIT_SECTIONS, NULL },
1014 .mismatch = DATA_TO_ANY_INIT,
1015 .symbol_white_list = {
1016 "*_template", "*_timer", "*_sht", "*_ops",
1017 "*_probe", "*_probe_one", "*_console", NULL
1021 .fromsec = { TEXT_SECTIONS, NULL },
1022 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1023 .mismatch = TEXT_TO_ANY_EXIT,
1024 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1027 .fromsec = { DATA_SECTIONS, NULL },
1028 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1029 .mismatch = DATA_TO_ANY_EXIT,
1030 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1032 /* Do not reference init code/data from meminit code/data */
1034 .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
1035 .bad_tosec = { INIT_SECTIONS, NULL },
1036 .mismatch = XXXINIT_TO_SOME_INIT,
1037 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1039 /* Do not reference exit code/data from memexit code/data */
1041 .fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
1042 .bad_tosec = { EXIT_SECTIONS, NULL },
1043 .mismatch = XXXEXIT_TO_SOME_EXIT,
1044 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1046 /* Do not use exit code/data from init code */
1048 .fromsec = { ALL_INIT_SECTIONS, NULL },
1049 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1050 .mismatch = ANY_INIT_TO_ANY_EXIT,
1051 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1053 /* Do not use init code/data from exit code */
1055 .fromsec = { ALL_EXIT_SECTIONS, NULL },
1056 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1057 .mismatch = ANY_EXIT_TO_ANY_INIT,
1058 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1061 .fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
1062 .bad_tosec = { INIT_SECTIONS, NULL },
1063 .mismatch = ANY_INIT_TO_ANY_EXIT,
1064 .symbol_white_list = { NULL },
1066 /* Do not export init/exit functions or data */
1068 .fromsec = { "__ksymtab*", NULL },
1069 .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
1070 .mismatch = EXPORT_TO_INIT_EXIT,
1071 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1074 .fromsec = { "__ex_table", NULL },
1075 /* If you're adding any new black-listed sections in here, consider
1076 * adding a special 'printer' for them in scripts/check_extable.
1078 .bad_tosec = { ".altinstr_replacement", NULL },
1079 .good_tosec = {ALL_TEXT_SECTIONS , NULL},
1080 .mismatch = EXTABLE_TO_NON_TEXT,
1081 .handler = extable_mismatch_handler,
1085 static const struct sectioncheck *section_mismatch(
1086 const char *fromsec, const char *tosec)
1089 int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
1090 const struct sectioncheck *check = §ioncheck[0];
1093 * The target section could be the SHT_NUL section when we're
1094 * handling relocations to un-resolved symbols, trying to match it
1095 * doesn't make much sense and causes build failures on parisc and
1096 * mn10300 architectures.
1101 for (i = 0; i < elems; i++) {
1102 if (match(fromsec, check->fromsec)) {
1103 if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
1105 if (check->good_tosec[0] && !match(tosec, check->good_tosec))
1114 * Whitelist to allow certain references to pass with no warning.
1117 * If a module parameter is declared __initdata and permissions=0
1118 * then this is legal despite the warning generated.
1119 * We cannot see value of permissions here, so just ignore
1121 * The pattern is identified by:
1122 * tosec = .init.data
1127 * module_param_call() ops can refer to __init set function if permissions=0
1128 * The pattern is identified by:
1129 * tosec = .init.text
1131 * atsym = __param_ops_*
1134 * Many drivers utilise a *driver container with references to
1135 * add, remove, probe functions etc.
1136 * the pattern is identified by:
1137 * tosec = init or exit section
1138 * fromsec = data section
1139 * atsym = *driver, *_template, *_sht, *_ops, *_probe,
1140 * *probe_one, *_console, *_timer
1143 * Whitelist all references from .head.text to any init section
1146 * Some symbols belong to init section but still it is ok to reference
1147 * these from non-init sections as these symbols don't have any memory
1148 * allocated for them and symbol address and value are same. So even
1149 * if init section is freed, its ok to reference those symbols.
1150 * For ex. symbols marking the init section boundaries.
1151 * This pattern is identified by
1152 * refsymname = __init_begin, _sinittext, _einittext
1155 * GCC may optimize static inlines when fed constant arg(s) resulting
1156 * in functions like cpumask_empty() -- generating an associated symbol
1157 * cpumask_empty.constprop.3 that appears in the audit. If the const that
1158 * is passed in comes from __init, like say nmi_ipi_mask, we get a
1159 * meaningless section warning. May need to add isra symbols too...
1160 * This pattern is identified by
1161 * tosec = init section
1162 * fromsec = text section
1163 * refsymname = *.constprop.*
1166 static int secref_whitelist(const struct sectioncheck *mismatch,
1167 const char *fromsec, const char *fromsym,
1168 const char *tosec, const char *tosym)
1170 /* Check for pattern 1 */
1171 if (match(tosec, init_data_sections) &&
1172 match(fromsec, data_sections) &&
1173 (strncmp(fromsym, "__param", strlen("__param")) == 0))
1176 /* Check for pattern 1a */
1177 if (strcmp(tosec, ".init.text") == 0 &&
1178 match(fromsec, data_sections) &&
1179 (strncmp(fromsym, "__param_ops_", strlen("__param_ops_")) == 0))
1182 /* Check for pattern 2 */
1183 if (match(tosec, init_exit_sections) &&
1184 match(fromsec, data_sections) &&
1185 match(fromsym, mismatch->symbol_white_list))
1188 /* Check for pattern 3 */
1189 if (match(fromsec, head_sections) &&
1190 match(tosec, init_sections))
1193 /* Check for pattern 4 */
1194 if (match(tosym, linker_symbols))
1197 /* Check for pattern 5 */
1198 if (match(fromsec, text_sections) &&
1199 match(tosec, init_sections) &&
1200 match(fromsym, optim_symbols))
1207 * Find symbol based on relocation record info.
1208 * In some cases the symbol supplied is a valid symbol so
1209 * return refsym. If st_name != 0 we assume this is a valid symbol.
1210 * In other cases the symbol needs to be looked up in the symbol table
1211 * based on section and address.
1213 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
1217 Elf_Sym *near = NULL;
1218 Elf64_Sword distance = 20;
1220 unsigned int relsym_secindex;
1222 if (relsym->st_name != 0)
1225 relsym_secindex = get_secindex(elf, relsym);
1226 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1227 if (get_secindex(elf, sym) != relsym_secindex)
1229 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
1231 if (sym->st_value == addr)
1233 /* Find a symbol nearby - addr are maybe negative */
1234 d = sym->st_value - addr;
1236 d = addr - sym->st_value;
1242 /* We need a close match */
1249 static inline int is_arm_mapping_symbol(const char *str)
1251 return str[0] == '$' && strchr("axtd", str[1])
1252 && (str[2] == '\0' || str[2] == '.');
1256 * If there's no name there, ignore it; likewise, ignore it if it's
1257 * one of the magic symbols emitted used by current ARM tools.
1259 * Otherwise if find_symbols_between() returns those symbols, they'll
1260 * fail the whitelist tests and cause lots of false alarms ... fixable
1261 * only by merging __exit and __init sections into __text, bloating
1262 * the kernel (which is especially evil on embedded platforms).
1264 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1266 const char *name = elf->strtab + sym->st_name;
1268 if (!name || !strlen(name))
1270 return !is_arm_mapping_symbol(name);
1274 * Find symbols before or equal addr and after addr - in the section sec.
1275 * If we find two symbols with equal offset prefer one with a valid name.
1276 * The ELF format may have a better way to detect what type of symbol
1277 * it is, but this works for now.
1279 static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1283 Elf_Sym *near = NULL;
1284 Elf_Addr distance = ~0;
1286 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1289 if (is_shndx_special(sym->st_shndx))
1291 symsec = sec_name(elf, get_secindex(elf, sym));
1292 if (strcmp(symsec, sec) != 0)
1294 if (!is_valid_name(elf, sym))
1296 if (sym->st_value <= addr) {
1297 if ((addr - sym->st_value) < distance) {
1298 distance = addr - sym->st_value;
1300 } else if ((addr - sym->st_value) == distance) {
1309 * Convert a section name to the function/data attribute
1310 * .init.text => __init
1311 * .memexitconst => __memconst
1314 * The memory of returned value has been allocated on a heap. The user of this
1315 * method should free it after usage.
1317 static char *sec2annotation(const char *s)
1319 if (match(s, init_exit_sections)) {
1320 char *p = malloc(20);
1327 while (*s && *s != '.')
1332 if (strstr(s, "rodata") != NULL)
1333 strcat(p, "const ");
1334 else if (strstr(s, "data") != NULL)
1344 static int is_function(Elf_Sym *sym)
1347 return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1352 static void print_section_list(const char * const list[20])
1354 const char *const *s = list;
1357 fprintf(stderr, "%s", *s);
1360 fprintf(stderr, ", ");
1362 fprintf(stderr, "\n");
1365 static inline void get_pretty_name(int is_func, const char** name, const char** name_p)
1368 case 0: *name = "variable"; *name_p = ""; break;
1369 case 1: *name = "function"; *name_p = "()"; break;
1370 default: *name = "(unknown reference)"; *name_p = ""; break;
1375 * Print a warning about a section mismatch.
1376 * Try to find symbols near it so user can find it.
1377 * Check whitelist before warning - it may be a false positive.
1379 static void report_sec_mismatch(const char *modname,
1380 const struct sectioncheck *mismatch,
1381 const char *fromsec,
1382 unsigned long long fromaddr,
1383 const char *fromsym,
1385 const char *tosec, const char *tosym,
1388 const char *from, *from_p;
1389 const char *to, *to_p;
1393 sec_mismatch_count++;
1394 if (!sec_mismatch_verbose)
1397 get_pretty_name(from_is_func, &from, &from_p);
1398 get_pretty_name(to_is_func, &to, &to_p);
1400 warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1401 "to the %s %s:%s%s\n",
1402 modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1405 switch (mismatch->mismatch) {
1406 case TEXT_TO_ANY_INIT:
1407 prl_from = sec2annotation(fromsec);
1408 prl_to = sec2annotation(tosec);
1410 "The function %s%s() references\n"
1412 "This is often because %s lacks a %s\n"
1413 "annotation or the annotation of %s is wrong.\n",
1415 to, prl_to, tosym, to_p,
1416 fromsym, prl_to, tosym);
1420 case DATA_TO_ANY_INIT: {
1421 prl_to = sec2annotation(tosec);
1423 "The variable %s references\n"
1425 "If the reference is valid then annotate the\n"
1426 "variable with __init* or __refdata (see linux/init.h) "
1427 "or name the variable:\n",
1428 fromsym, to, prl_to, tosym, to_p);
1429 print_section_list(mismatch->symbol_white_list);
1433 case TEXT_TO_ANY_EXIT:
1434 prl_to = sec2annotation(tosec);
1436 "The function %s() references a %s in an exit section.\n"
1437 "Often the %s %s%s has valid usage outside the exit section\n"
1438 "and the fix is to remove the %sannotation of %s.\n",
1439 fromsym, to, to, tosym, to_p, prl_to, tosym);
1442 case DATA_TO_ANY_EXIT: {
1443 prl_to = sec2annotation(tosec);
1445 "The variable %s references\n"
1447 "If the reference is valid then annotate the\n"
1448 "variable with __exit* (see linux/init.h) or "
1449 "name the variable:\n",
1450 fromsym, to, prl_to, tosym, to_p);
1451 print_section_list(mismatch->symbol_white_list);
1455 case XXXINIT_TO_SOME_INIT:
1456 case XXXEXIT_TO_SOME_EXIT:
1457 prl_from = sec2annotation(fromsec);
1458 prl_to = sec2annotation(tosec);
1460 "The %s %s%s%s references\n"
1462 "If %s is only used by %s then\n"
1463 "annotate %s with a matching annotation.\n",
1464 from, prl_from, fromsym, from_p,
1465 to, prl_to, tosym, to_p,
1466 tosym, fromsym, tosym);
1470 case ANY_INIT_TO_ANY_EXIT:
1471 prl_from = sec2annotation(fromsec);
1472 prl_to = sec2annotation(tosec);
1474 "The %s %s%s%s references\n"
1476 "This is often seen when error handling "
1477 "in the init function\n"
1478 "uses functionality in the exit path.\n"
1479 "The fix is often to remove the %sannotation of\n"
1480 "%s%s so it may be used outside an exit section.\n",
1481 from, prl_from, fromsym, from_p,
1482 to, prl_to, tosym, to_p,
1483 prl_to, tosym, to_p);
1487 case ANY_EXIT_TO_ANY_INIT:
1488 prl_from = sec2annotation(fromsec);
1489 prl_to = sec2annotation(tosec);
1491 "The %s %s%s%s references\n"
1493 "This is often seen when error handling "
1494 "in the exit function\n"
1495 "uses functionality in the init path.\n"
1496 "The fix is often to remove the %sannotation of\n"
1497 "%s%s so it may be used outside an init section.\n",
1498 from, prl_from, fromsym, from_p,
1499 to, prl_to, tosym, to_p,
1500 prl_to, tosym, to_p);
1504 case EXPORT_TO_INIT_EXIT:
1505 prl_to = sec2annotation(tosec);
1507 "The symbol %s is exported and annotated %s\n"
1508 "Fix this by removing the %sannotation of %s "
1509 "or drop the export.\n",
1510 tosym, prl_to, prl_to, tosym);
1513 case EXTABLE_TO_NON_TEXT:
1514 fatal("There's a special handler for this mismatch type, "
1515 "we should never get here.");
1518 fprintf(stderr, "\n");
1521 static void default_mismatch_handler(const char *modname, struct elf_info *elf,
1522 const struct sectioncheck* const mismatch,
1523 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1529 const char *fromsym;
1531 from = find_elf_symbol2(elf, r->r_offset, fromsec);
1532 fromsym = sym_name(elf, from);
1534 if (!strncmp(fromsym, "reference___initcall",
1535 sizeof("reference___initcall")-1))
1538 tosec = sec_name(elf, get_secindex(elf, sym));
1539 to = find_elf_symbol(elf, r->r_addend, sym);
1540 tosym = sym_name(elf, to);
1542 /* check whitelist - we may ignore it */
1543 if (secref_whitelist(mismatch,
1544 fromsec, fromsym, tosec, tosym)) {
1545 report_sec_mismatch(modname, mismatch,
1546 fromsec, r->r_offset, fromsym,
1547 is_function(from), tosec, tosym,
1552 static int is_executable_section(struct elf_info* elf, unsigned int section_index)
1554 if (section_index > elf->num_sections)
1555 fatal("section_index is outside elf->num_sections!\n");
1557 return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR);
1561 * We rely on a gross hack in section_rel[a]() calling find_extable_entry_size()
1562 * to know the sizeof(struct exception_table_entry) for the target architecture.
1564 static unsigned int extable_entry_size = 0;
1565 static void find_extable_entry_size(const char* const sec, const Elf_Rela* r)
1568 * If we're currently checking the second relocation within __ex_table,
1569 * that relocation offset tells us the offsetof(struct
1570 * exception_table_entry, fixup) which is equal to sizeof(struct
1571 * exception_table_entry) divided by two. We use that to our advantage
1572 * since there's no portable way to get that size as every architecture
1573 * seems to go with different sized types. Not pretty but better than
1574 * hard-coding the size for every architecture..
1576 if (!extable_entry_size)
1577 extable_entry_size = r->r_offset * 2;
1580 static inline bool is_extable_fault_address(Elf_Rela *r)
1583 * extable_entry_size is only discovered after we've handled the
1584 * _second_ relocation in __ex_table, so only abort when we're not
1585 * handling the first reloc and extable_entry_size is zero.
1587 if (r->r_offset && extable_entry_size == 0)
1588 fatal("extable_entry size hasn't been discovered!\n");
1590 return ((r->r_offset == 0) ||
1591 (r->r_offset % extable_entry_size == 0));
1594 #define is_second_extable_reloc(Start, Cur, Sec) \
1595 (((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0))
1597 static void report_extable_warnings(const char* modname, struct elf_info* elf,
1598 const struct sectioncheck* const mismatch,
1599 Elf_Rela* r, Elf_Sym* sym,
1600 const char* fromsec, const char* tosec)
1602 Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec);
1603 const char* fromsym_name = sym_name(elf, fromsym);
1604 Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym);
1605 const char* tosym_name = sym_name(elf, tosym);
1606 const char* from_pretty_name;
1607 const char* from_pretty_name_p;
1608 const char* to_pretty_name;
1609 const char* to_pretty_name_p;
1611 get_pretty_name(is_function(fromsym),
1612 &from_pretty_name, &from_pretty_name_p);
1613 get_pretty_name(is_function(tosym),
1614 &to_pretty_name, &to_pretty_name_p);
1616 warn("%s(%s+0x%lx): Section mismatch in reference"
1617 " from the %s %s%s to the %s %s:%s%s\n",
1618 modname, fromsec, (long)r->r_offset, from_pretty_name,
1619 fromsym_name, from_pretty_name_p,
1620 to_pretty_name, tosec, tosym_name, to_pretty_name_p);
1622 if (!match(tosec, mismatch->bad_tosec) &&
1623 is_executable_section(elf, get_secindex(elf, sym)))
1625 "The relocation at %s+0x%lx references\n"
1626 "section \"%s\" which is not in the list of\n"
1627 "authorized sections. If you're adding a new section\n"
1628 "and/or if this reference is valid, add \"%s\" to the\n"
1629 "list of authorized sections to jump to on fault.\n"
1630 "This can be achieved by adding \"%s\" to \n"
1631 "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
1632 fromsec, (long)r->r_offset, tosec, tosec, tosec);
1635 static void extable_mismatch_handler(const char* modname, struct elf_info *elf,
1636 const struct sectioncheck* const mismatch,
1637 Elf_Rela* r, Elf_Sym* sym,
1638 const char *fromsec)
1640 const char* tosec = sec_name(elf, get_secindex(elf, sym));
1642 sec_mismatch_count++;
1644 if (sec_mismatch_verbose)
1645 report_extable_warnings(modname, elf, mismatch, r, sym,
1648 if (match(tosec, mismatch->bad_tosec))
1649 fatal("The relocation at %s+0x%lx references\n"
1650 "section \"%s\" which is black-listed.\n"
1651 "Something is seriously wrong and should be fixed.\n"
1652 "You might get more information about where this is\n"
1653 "coming from by using scripts/check_extable.sh %s\n",
1654 fromsec, (long)r->r_offset, tosec, modname);
1655 else if (!is_executable_section(elf, get_secindex(elf, sym))) {
1656 if (is_extable_fault_address(r))
1657 fatal("The relocation at %s+0x%lx references\n"
1658 "section \"%s\" which is not executable, IOW\n"
1659 "it is not possible for the kernel to fault\n"
1660 "at that address. Something is seriously wrong\n"
1661 "and should be fixed.\n",
1662 fromsec, (long)r->r_offset, tosec);
1664 fatal("The relocation at %s+0x%lx references\n"
1665 "section \"%s\" which is not executable, IOW\n"
1666 "the kernel will fault if it ever tries to\n"
1667 "jump to it. Something is seriously wrong\n"
1668 "and should be fixed.\n",
1669 fromsec, (long)r->r_offset, tosec);
1673 static void check_section_mismatch(const char *modname, struct elf_info *elf,
1674 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1676 const char *tosec = sec_name(elf, get_secindex(elf, sym));;
1677 const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec);
1680 if (mismatch->handler)
1681 mismatch->handler(modname, elf, mismatch,
1684 default_mismatch_handler(modname, elf, mismatch,
1689 static unsigned int *reloc_location(struct elf_info *elf,
1690 Elf_Shdr *sechdr, Elf_Rela *r)
1692 Elf_Shdr *sechdrs = elf->sechdrs;
1693 int section = sechdr->sh_info;
1695 return (void *)elf->hdr + sechdrs[section].sh_offset +
1699 static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1701 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1702 unsigned int *location = reloc_location(elf, sechdr, r);
1706 r->r_addend = TO_NATIVE(*location);
1709 r->r_addend = TO_NATIVE(*location) + 4;
1710 /* For CONFIG_RELOCATABLE=y */
1711 if (elf->hdr->e_type == ET_EXEC)
1712 r->r_addend += r->r_offset;
1719 #define R_ARM_CALL 28
1721 #ifndef R_ARM_JUMP24
1722 #define R_ARM_JUMP24 29
1725 #ifndef R_ARM_THM_CALL
1726 #define R_ARM_THM_CALL 10
1728 #ifndef R_ARM_THM_JUMP24
1729 #define R_ARM_THM_JUMP24 30
1731 #ifndef R_ARM_THM_JUMP19
1732 #define R_ARM_THM_JUMP19 51
1735 static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1737 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1741 /* From ARM ABI: (S + A) | T */
1742 r->r_addend = (int)(long)
1743 (elf->symtab_start + ELF_R_SYM(r->r_info));
1748 case R_ARM_THM_CALL:
1749 case R_ARM_THM_JUMP24:
1750 case R_ARM_THM_JUMP19:
1751 /* From ARM ABI: ((S + A) | T) - P */
1752 r->r_addend = (int)(long)(elf->hdr +
1754 (r->r_offset - sechdr->sh_addr));
1762 static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1764 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1765 unsigned int *location = reloc_location(elf, sechdr, r);
1768 if (r_typ == R_MIPS_HI16)
1769 return 1; /* skip this */
1770 inst = TO_NATIVE(*location);
1773 r->r_addend = inst & 0xffff;
1776 r->r_addend = (inst & 0x03ffffff) << 2;
1785 static void section_rela(const char *modname, struct elf_info *elf,
1792 const char *fromsec;
1794 Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1795 Elf_Rela *stop = (void *)start + sechdr->sh_size;
1797 fromsec = sech_name(elf, sechdr);
1798 fromsec += strlen(".rela");
1799 /* if from section (name) is know good then skip it */
1800 if (match(fromsec, section_white_list))
1803 for (rela = start; rela < stop; rela++) {
1804 r.r_offset = TO_NATIVE(rela->r_offset);
1805 #if KERNEL_ELFCLASS == ELFCLASS64
1806 if (elf->hdr->e_machine == EM_MIPS) {
1808 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1809 r_sym = TO_NATIVE(r_sym);
1810 r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1811 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1813 r.r_info = TO_NATIVE(rela->r_info);
1814 r_sym = ELF_R_SYM(r.r_info);
1817 r.r_info = TO_NATIVE(rela->r_info);
1818 r_sym = ELF_R_SYM(r.r_info);
1820 r.r_addend = TO_NATIVE(rela->r_addend);
1821 sym = elf->symtab_start + r_sym;
1822 /* Skip special sections */
1823 if (is_shndx_special(sym->st_shndx))
1825 if (is_second_extable_reloc(start, rela, fromsec))
1826 find_extable_entry_size(fromsec, &r);
1827 check_section_mismatch(modname, elf, &r, sym, fromsec);
1831 static void section_rel(const char *modname, struct elf_info *elf,
1838 const char *fromsec;
1840 Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1841 Elf_Rel *stop = (void *)start + sechdr->sh_size;
1843 fromsec = sech_name(elf, sechdr);
1844 fromsec += strlen(".rel");
1845 /* if from section (name) is know good then skip it */
1846 if (match(fromsec, section_white_list))
1849 for (rel = start; rel < stop; rel++) {
1850 r.r_offset = TO_NATIVE(rel->r_offset);
1851 #if KERNEL_ELFCLASS == ELFCLASS64
1852 if (elf->hdr->e_machine == EM_MIPS) {
1854 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1855 r_sym = TO_NATIVE(r_sym);
1856 r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1857 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1859 r.r_info = TO_NATIVE(rel->r_info);
1860 r_sym = ELF_R_SYM(r.r_info);
1863 r.r_info = TO_NATIVE(rel->r_info);
1864 r_sym = ELF_R_SYM(r.r_info);
1867 switch (elf->hdr->e_machine) {
1869 if (addend_386_rel(elf, sechdr, &r))
1873 if (addend_arm_rel(elf, sechdr, &r))
1877 if (addend_mips_rel(elf, sechdr, &r))
1881 sym = elf->symtab_start + r_sym;
1882 /* Skip special sections */
1883 if (is_shndx_special(sym->st_shndx))
1885 if (is_second_extable_reloc(start, rel, fromsec))
1886 find_extable_entry_size(fromsec, &r);
1887 check_section_mismatch(modname, elf, &r, sym, fromsec);
1892 * A module includes a number of sections that are discarded
1893 * either when loaded or when used as built-in.
1894 * For loaded modules all functions marked __init and all data
1895 * marked __initdata will be discarded when the module has been initialized.
1896 * Likewise for modules used built-in the sections marked __exit
1897 * are discarded because __exit marked function are supposed to be called
1898 * only when a module is unloaded which never happens for built-in modules.
1899 * The check_sec_ref() function traverses all relocation records
1900 * to find all references to a section that reference a section that will
1901 * be discarded and warns about it.
1903 static void check_sec_ref(struct module *mod, const char *modname,
1904 struct elf_info *elf)
1907 Elf_Shdr *sechdrs = elf->sechdrs;
1909 /* Walk through all sections */
1910 for (i = 0; i < elf->num_sections; i++) {
1911 check_section(modname, elf, &elf->sechdrs[i]);
1912 /* We want to process only relocation sections and not .init */
1913 if (sechdrs[i].sh_type == SHT_RELA)
1914 section_rela(modname, elf, &elf->sechdrs[i]);
1915 else if (sechdrs[i].sh_type == SHT_REL)
1916 section_rel(modname, elf, &elf->sechdrs[i]);
1920 static char *remove_dot(char *s)
1922 size_t n = strcspn(s, ".");
1925 size_t m = strspn(s + n + 1, "0123456789");
1926 if (m && (s[n + m] == '.' || s[n + m] == 0))
1932 static void read_symbols(char *modname)
1934 const char *symname;
1938 struct elf_info info = { };
1941 if (!parse_elf(&info, modname))
1944 mod = new_module(modname);
1946 /* When there's no vmlinux, don't print warnings about
1947 * unresolved symbols (since there'll be too many ;) */
1948 if (is_vmlinux(modname)) {
1953 license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1954 if (info.modinfo && !license && !is_vmlinux(modname))
1955 warn("modpost: missing MODULE_LICENSE() in %s\n"
1956 "see include/linux/module.h for "
1957 "more information\n", modname);
1959 if (license_is_gpl_compatible(license))
1960 mod->gpl_compatible = 1;
1962 mod->gpl_compatible = 0;
1965 license = get_next_modinfo(info.modinfo, info.modinfo_len,
1966 "license", license);
1969 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1970 symname = remove_dot(info.strtab + sym->st_name);
1972 handle_modversions(mod, &info, sym, symname);
1973 handle_moddevtable(mod, &info, sym, symname);
1975 if (!is_vmlinux(modname) ||
1976 (is_vmlinux(modname) && vmlinux_section_warnings))
1977 check_sec_ref(mod, modname, &info);
1979 version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1981 maybe_frob_rcs_version(modname, version, info.modinfo,
1982 version - (char *)info.hdr);
1983 if (version || (all_versions && !is_vmlinux(modname)))
1984 get_src_version(modname, mod->srcversion,
1985 sizeof(mod->srcversion)-1);
1987 parse_elf_finish(&info);
1989 /* Our trick to get versioning for module struct etc. - it's
1990 * never passed as an argument to an exported function, so
1991 * the automatic versioning doesn't pick it up, but it's really
1992 * important anyhow */
1994 mod->unres = alloc_symbol("module_layout", 0, mod->unres);
1997 static void read_symbols_from_files(const char *filename)
2000 char fname[PATH_MAX];
2002 if (strcmp(filename, "-") != 0) {
2003 in = fopen(filename, "r");
2005 fatal("Can't open filenames file %s: %m", filename);
2008 while (fgets(fname, PATH_MAX, in) != NULL) {
2009 if (strends(fname, "\n"))
2010 fname[strlen(fname)-1] = '\0';
2011 read_symbols(fname);
2020 /* We first write the generated file into memory using the
2021 * following helper, then compare to the file on disk and
2022 * only update the later if anything changed */
2024 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
2025 const char *fmt, ...)
2032 len = vsnprintf(tmp, SZ, fmt, ap);
2033 buf_write(buf, tmp, len);
2037 void buf_write(struct buffer *buf, const char *s, int len)
2039 if (buf->size - buf->pos < len) {
2040 buf->size += len + SZ;
2041 buf->p = realloc(buf->p, buf->size);
2043 strncpy(buf->p + buf->pos, s, len);
2047 static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
2049 const char *e = is_vmlinux(m) ?"":".ko";
2053 fatal("modpost: GPL-incompatible module %s%s "
2054 "uses GPL-only symbol '%s'\n", m, e, s);
2056 case export_unused_gpl:
2057 fatal("modpost: GPL-incompatible module %s%s "
2058 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
2060 case export_gpl_future:
2061 warn("modpost: GPL-incompatible module %s%s "
2062 "uses future GPL-only symbol '%s'\n", m, e, s);
2066 case export_unknown:
2072 static void check_for_unused(enum export exp, const char *m, const char *s)
2074 const char *e = is_vmlinux(m) ?"":".ko";
2078 case export_unused_gpl:
2079 warn("modpost: module %s%s "
2080 "uses symbol '%s' marked UNUSED\n", m, e, s);
2088 static void check_exports(struct module *mod)
2090 struct symbol *s, *exp;
2092 for (s = mod->unres; s; s = s->next) {
2093 const char *basename;
2094 exp = find_symbol(s->name);
2095 if (!exp || exp->module == mod)
2097 basename = strrchr(mod->name, '/');
2101 basename = mod->name;
2102 if (!mod->gpl_compatible)
2103 check_for_gpl_usage(exp->export, basename, exp->name);
2104 check_for_unused(exp->export, basename, exp->name);
2109 * Header for the generated file
2111 static void add_header(struct buffer *b, struct module *mod)
2113 buf_printf(b, "#include <linux/module.h>\n");
2114 buf_printf(b, "#include <linux/vermagic.h>\n");
2115 buf_printf(b, "#include <linux/compiler.h>\n");
2116 buf_printf(b, "\n");
2117 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
2118 buf_printf(b, "\n");
2119 buf_printf(b, "__visible struct module __this_module\n");
2120 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
2121 buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
2123 buf_printf(b, "\t.init = init_module,\n");
2124 if (mod->has_cleanup)
2125 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
2126 "\t.exit = cleanup_module,\n"
2128 buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
2129 buf_printf(b, "};\n");
2132 static void add_intree_flag(struct buffer *b, int is_intree)
2135 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
2138 static void add_staging_flag(struct buffer *b, const char *name)
2140 static const char *staging_dir = "drivers/staging";
2142 if (strncmp(staging_dir, name, strlen(staging_dir)) == 0)
2143 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
2146 /* In kernel, this size is defined in linux/module.h;
2147 * here we use Elf_Addr instead of long for covering cross-compile
2149 #define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
2152 * Record CRCs for unresolved symbols
2154 static int add_versions(struct buffer *b, struct module *mod)
2156 struct symbol *s, *exp;
2159 for (s = mod->unres; s; s = s->next) {
2160 exp = find_symbol(s->name);
2161 if (!exp || exp->module == mod) {
2162 if (have_vmlinux && !s->weak) {
2163 if (warn_unresolved) {
2164 warn("\"%s\" [%s.ko] undefined!\n",
2165 s->name, mod->name);
2167 merror("\"%s\" [%s.ko] undefined!\n",
2168 s->name, mod->name);
2174 s->module = exp->module;
2175 s->crc_valid = exp->crc_valid;
2182 buf_printf(b, "\n");
2183 buf_printf(b, "static const struct modversion_info ____versions[]\n");
2184 buf_printf(b, "__used\n");
2185 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
2187 for (s = mod->unres; s; s = s->next) {
2190 if (!s->crc_valid) {
2191 warn("\"%s\" [%s.ko] has no CRC!\n",
2192 s->name, mod->name);
2195 if (strlen(s->name) >= MODULE_NAME_LEN) {
2196 merror("too long symbol \"%s\" [%s.ko]\n",
2197 s->name, mod->name);
2201 buf_printf(b, "\t{ %#8x, __VMLINUX_SYMBOL_STR(%s) },\n",
2205 buf_printf(b, "};\n");
2210 static void add_depends(struct buffer *b, struct module *mod,
2211 struct module *modules)
2217 for (m = modules; m; m = m->next)
2218 m->seen = is_vmlinux(m->name);
2220 buf_printf(b, "\n");
2221 buf_printf(b, "static const char __module_depends[]\n");
2222 buf_printf(b, "__used\n");
2223 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
2224 buf_printf(b, "\"depends=");
2225 for (s = mod->unres; s; s = s->next) {
2230 if (s->module->seen)
2233 s->module->seen = 1;
2234 p = strrchr(s->module->name, '/');
2238 p = s->module->name;
2239 buf_printf(b, "%s%s", first ? "" : ",", p);
2242 buf_printf(b, "\";\n");
2245 static void add_srcversion(struct buffer *b, struct module *mod)
2247 if (mod->srcversion[0]) {
2248 buf_printf(b, "\n");
2249 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
2254 static void write_if_changed(struct buffer *b, const char *fname)
2260 file = fopen(fname, "r");
2264 if (fstat(fileno(file), &st) < 0)
2267 if (st.st_size != b->pos)
2270 tmp = NOFAIL(malloc(b->pos));
2271 if (fread(tmp, 1, b->pos, file) != b->pos)
2274 if (memcmp(tmp, b->p, b->pos) != 0)
2286 file = fopen(fname, "w");
2291 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
2298 /* parse Module.symvers file. line format:
2299 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
2301 static void read_dump(const char *fname, unsigned int kernel)
2303 unsigned long size, pos = 0;
2304 void *file = grab_file(fname, &size);
2308 /* No symbol versions, silently ignore */
2311 while ((line = get_next_line(&pos, file, size))) {
2312 char *symname, *modname, *d, *export, *end;
2317 if (!(symname = strchr(line, '\t')))
2320 if (!(modname = strchr(symname, '\t')))
2323 if ((export = strchr(modname, '\t')) != NULL)
2325 if (export && ((end = strchr(export, '\t')) != NULL))
2327 crc = strtoul(line, &d, 16);
2328 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2330 mod = find_module(modname);
2332 if (is_vmlinux(modname))
2334 mod = new_module(modname);
2337 s = sym_add_exported(symname, mod, export_no(export));
2340 sym_update_crc(symname, mod, crc, export_no(export));
2342 release_file(file, size);
2345 release_file(file, size);
2346 fatal("parse error in symbol dump file\n");
2349 /* For normal builds always dump all symbols.
2350 * For external modules only dump symbols
2351 * that are not read from kernel Module.symvers.
2353 static int dump_sym(struct symbol *sym)
2355 if (!external_module)
2357 if (sym->vmlinux || sym->kernel)
2362 static void write_dump(const char *fname)
2364 struct buffer buf = { };
2365 struct symbol *symbol;
2368 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
2369 symbol = symbolhash[n];
2371 if (dump_sym(symbol))
2372 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
2373 symbol->crc, symbol->name,
2374 symbol->module->name,
2375 export_str(symbol->export));
2376 symbol = symbol->next;
2379 write_if_changed(&buf, fname);
2383 struct ext_sym_list {
2384 struct ext_sym_list *next;
2388 int main(int argc, char **argv)
2391 struct buffer buf = { };
2392 char *kernel_read = NULL, *module_read = NULL;
2393 char *dump_write = NULL, *files_source = NULL;
2396 struct ext_sym_list *extsym_iter;
2397 struct ext_sym_list *extsym_start = NULL;
2399 while ((opt = getopt(argc, argv, "i:I:e:mnsST:o:awM:K:E")) != -1) {
2402 kernel_read = optarg;
2405 module_read = optarg;
2406 external_module = 1;
2409 external_module = 1;
2411 NOFAIL(malloc(sizeof(*extsym_iter)));
2412 extsym_iter->next = extsym_start;
2413 extsym_iter->file = optarg;
2414 extsym_start = extsym_iter;
2420 ignore_missing_files = 1;
2423 dump_write = optarg;
2429 vmlinux_section_warnings = 0;
2432 sec_mismatch_verbose = 0;
2435 files_source = optarg;
2438 warn_unresolved = 1;
2441 sec_mismatch_fatal = 1;
2449 read_dump(kernel_read, 1);
2451 read_dump(module_read, 0);
2452 while (extsym_start) {
2453 read_dump(extsym_start->file, 0);
2454 extsym_iter = extsym_start->next;
2456 extsym_start = extsym_iter;
2459 while (optind < argc)
2460 read_symbols(argv[optind++]);
2463 read_symbols_from_files(files_source);
2465 for (mod = modules; mod; mod = mod->next) {
2473 for (mod = modules; mod; mod = mod->next) {
2474 char fname[PATH_MAX];
2481 add_header(&buf, mod);
2482 add_intree_flag(&buf, !external_module);
2483 add_staging_flag(&buf, mod->name);
2484 err |= add_versions(&buf, mod);
2485 add_depends(&buf, mod, modules);
2486 add_moddevtable(&buf, mod);
2487 add_srcversion(&buf, mod);
2489 sprintf(fname, "%s.mod.c", mod->name);
2490 write_if_changed(&buf, fname);
2493 write_dump(dump_write);
2494 if (sec_mismatch_count) {
2495 if (!sec_mismatch_verbose) {
2496 warn("modpost: Found %d section mismatch(es).\n"
2497 "To see full details build your kernel with:\n"
2498 "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n",
2499 sec_mismatch_count);
2501 if (sec_mismatch_fatal) {
2502 fatal("modpost: Section mismatches detected.\n"
2503 "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");