MN10300: Permit .GCC-command-line sections
[linux-2.6.git] / scripts / mod / modpost.c
blob253c107b9a9912305a3ba18b07d86b065149bd89
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 ...
14 #define _GNU_SOURCE
15 #include <stdio.h>
16 #include <ctype.h>
17 #include <string.h>
18 #include "modpost.h"
19 #include "../../include/generated/autoconf.h"
20 #include "../../include/linux/license.h"
22 /* Some toolchains use a `_' prefix for all user symbols. */
23 #ifdef CONFIG_SYMBOL_PREFIX
24 #define MODULE_SYMBOL_PREFIX CONFIG_SYMBOL_PREFIX
25 #else
26 #define MODULE_SYMBOL_PREFIX ""
27 #endif
30 /* Are we using CONFIG_MODVERSIONS? */
31 int modversions = 0;
32 /* Warn about undefined symbols? (do so if we have vmlinux) */
33 int have_vmlinux = 0;
34 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */
35 static int all_versions = 0;
36 /* If we are modposting external module set to 1 */
37 static int external_module = 0;
38 /* Warn about section mismatch in vmlinux if set to 1 */
39 static int vmlinux_section_warnings = 1;
40 /* Only warn about unresolved symbols */
41 static int warn_unresolved = 0;
42 /* How a symbol is exported */
43 static int sec_mismatch_count = 0;
44 static int sec_mismatch_verbose = 1;
46 enum export {
47 export_plain, export_unused, export_gpl,
48 export_unused_gpl, export_gpl_future, export_unknown
51 #define PRINTF __attribute__ ((format (printf, 1, 2)))
53 PRINTF void fatal(const char *fmt, ...)
55 va_list arglist;
57 fprintf(stderr, "FATAL: ");
59 va_start(arglist, fmt);
60 vfprintf(stderr, fmt, arglist);
61 va_end(arglist);
63 exit(1);
66 PRINTF void warn(const char *fmt, ...)
68 va_list arglist;
70 fprintf(stderr, "WARNING: ");
72 va_start(arglist, fmt);
73 vfprintf(stderr, fmt, arglist);
74 va_end(arglist);
77 PRINTF void merror(const char *fmt, ...)
79 va_list arglist;
81 fprintf(stderr, "ERROR: ");
83 va_start(arglist, fmt);
84 vfprintf(stderr, fmt, arglist);
85 va_end(arglist);
88 static int is_vmlinux(const char *modname)
90 const char *myname;
92 myname = strrchr(modname, '/');
93 if (myname)
94 myname++;
95 else
96 myname = modname;
98 return (strcmp(myname, "vmlinux") == 0) ||
99 (strcmp(myname, "vmlinux.o") == 0);
102 void *do_nofail(void *ptr, const char *expr)
104 if (!ptr)
105 fatal("modpost: Memory allocation failure: %s.\n", expr);
107 return ptr;
110 /* A list of all modules we processed */
111 static struct module *modules;
113 static struct module *find_module(char *modname)
115 struct module *mod;
117 for (mod = modules; mod; mod = mod->next)
118 if (strcmp(mod->name, modname) == 0)
119 break;
120 return mod;
123 static struct module *new_module(char *modname)
125 struct module *mod;
126 char *p, *s;
128 mod = NOFAIL(malloc(sizeof(*mod)));
129 memset(mod, 0, sizeof(*mod));
130 p = NOFAIL(strdup(modname));
132 /* strip trailing .o */
133 s = strrchr(p, '.');
134 if (s != NULL)
135 if (strcmp(s, ".o") == 0)
136 *s = '\0';
138 /* add to list */
139 mod->name = p;
140 mod->gpl_compatible = -1;
141 mod->next = modules;
142 modules = mod;
144 return mod;
147 /* A hash of all exported symbols,
148 * struct symbol is also used for lists of unresolved symbols */
150 #define SYMBOL_HASH_SIZE 1024
152 struct symbol {
153 struct symbol *next;
154 struct module *module;
155 unsigned int crc;
156 int crc_valid;
157 unsigned int weak:1;
158 unsigned int vmlinux:1; /* 1 if symbol is defined in vmlinux */
159 unsigned int kernel:1; /* 1 if symbol is from kernel
160 * (only for external modules) **/
161 unsigned int preloaded:1; /* 1 if symbol from Module.symvers */
162 enum export export; /* Type of export */
163 char name[0];
166 static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
168 /* This is based on the hash agorithm from gdbm, via tdb */
169 static inline unsigned int tdb_hash(const char *name)
171 unsigned value; /* Used to compute the hash value. */
172 unsigned i; /* Used to cycle through random values. */
174 /* Set the initial value from the key size. */
175 for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
176 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
178 return (1103515243 * value + 12345);
182 * Allocate a new symbols for use in the hash of exported symbols or
183 * the list of unresolved symbols per module
185 static struct symbol *alloc_symbol(const char *name, unsigned int weak,
186 struct symbol *next)
188 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
190 memset(s, 0, sizeof(*s));
191 strcpy(s->name, name);
192 s->weak = weak;
193 s->next = next;
194 return s;
197 /* For the hash of exported symbols */
198 static struct symbol *new_symbol(const char *name, struct module *module,
199 enum export export)
201 unsigned int hash;
202 struct symbol *new;
204 hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
205 new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
206 new->module = module;
207 new->export = export;
208 return new;
211 static struct symbol *find_symbol(const char *name)
213 struct symbol *s;
215 /* For our purposes, .foo matches foo. PPC64 needs this. */
216 if (name[0] == '.')
217 name++;
219 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
220 if (strcmp(s->name, name) == 0)
221 return s;
223 return NULL;
226 static struct {
227 const char *str;
228 enum export export;
229 } export_list[] = {
230 { .str = "EXPORT_SYMBOL", .export = export_plain },
231 { .str = "EXPORT_UNUSED_SYMBOL", .export = export_unused },
232 { .str = "EXPORT_SYMBOL_GPL", .export = export_gpl },
233 { .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
234 { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
235 { .str = "(unknown)", .export = export_unknown },
239 static const char *export_str(enum export ex)
241 return export_list[ex].str;
244 static enum export export_no(const char *s)
246 int i;
248 if (!s)
249 return export_unknown;
250 for (i = 0; export_list[i].export != export_unknown; i++) {
251 if (strcmp(export_list[i].str, s) == 0)
252 return export_list[i].export;
254 return export_unknown;
257 static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
259 if (sec == elf->export_sec)
260 return export_plain;
261 else if (sec == elf->export_unused_sec)
262 return export_unused;
263 else if (sec == elf->export_gpl_sec)
264 return export_gpl;
265 else if (sec == elf->export_unused_gpl_sec)
266 return export_unused_gpl;
267 else if (sec == elf->export_gpl_future_sec)
268 return export_gpl_future;
269 else
270 return export_unknown;
274 * Add an exported symbol - it may have already been added without a
275 * CRC, in this case just update the CRC
277 static struct symbol *sym_add_exported(const char *name, struct module *mod,
278 enum export export)
280 struct symbol *s = find_symbol(name);
282 if (!s) {
283 s = new_symbol(name, mod, export);
284 } else {
285 if (!s->preloaded) {
286 warn("%s: '%s' exported twice. Previous export "
287 "was in %s%s\n", mod->name, name,
288 s->module->name,
289 is_vmlinux(s->module->name) ?"":".ko");
290 } else {
291 /* In case Modules.symvers was out of date */
292 s->module = mod;
295 s->preloaded = 0;
296 s->vmlinux = is_vmlinux(mod->name);
297 s->kernel = 0;
298 s->export = export;
299 return s;
302 static void sym_update_crc(const char *name, struct module *mod,
303 unsigned int crc, enum export export)
305 struct symbol *s = find_symbol(name);
307 if (!s)
308 s = new_symbol(name, mod, export);
309 s->crc = crc;
310 s->crc_valid = 1;
313 void *grab_file(const char *filename, unsigned long *size)
315 struct stat st;
316 void *map;
317 int fd;
319 fd = open(filename, O_RDONLY);
320 if (fd < 0 || fstat(fd, &st) != 0)
321 return NULL;
323 *size = st.st_size;
324 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
325 close(fd);
327 if (map == MAP_FAILED)
328 return NULL;
329 return map;
333 * Return a copy of the next line in a mmap'ed file.
334 * spaces in the beginning of the line is trimmed away.
335 * Return a pointer to a static buffer.
337 char *get_next_line(unsigned long *pos, void *file, unsigned long size)
339 static char line[4096];
340 int skip = 1;
341 size_t len = 0;
342 signed char *p = (signed char *)file + *pos;
343 char *s = line;
345 for (; *pos < size ; (*pos)++) {
346 if (skip && isspace(*p)) {
347 p++;
348 continue;
350 skip = 0;
351 if (*p != '\n' && (*pos < size)) {
352 len++;
353 *s++ = *p++;
354 if (len > 4095)
355 break; /* Too long, stop */
356 } else {
357 /* End of string */
358 *s = '\0';
359 return line;
362 /* End of buffer */
363 return NULL;
366 void release_file(void *file, unsigned long size)
368 munmap(file, size);
371 static int parse_elf(struct elf_info *info, const char *filename)
373 unsigned int i;
374 Elf_Ehdr *hdr;
375 Elf_Shdr *sechdrs;
376 Elf_Sym *sym;
377 const char *secstrings;
378 unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
380 hdr = grab_file(filename, &info->size);
381 if (!hdr) {
382 perror(filename);
383 exit(1);
385 info->hdr = hdr;
386 if (info->size < sizeof(*hdr)) {
387 /* file too small, assume this is an empty .o file */
388 return 0;
390 /* Is this a valid ELF file? */
391 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
392 (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
393 (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
394 (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
395 /* Not an ELF file - silently ignore it */
396 return 0;
398 /* Fix endianness in ELF header */
399 hdr->e_type = TO_NATIVE(hdr->e_type);
400 hdr->e_machine = TO_NATIVE(hdr->e_machine);
401 hdr->e_version = TO_NATIVE(hdr->e_version);
402 hdr->e_entry = TO_NATIVE(hdr->e_entry);
403 hdr->e_phoff = TO_NATIVE(hdr->e_phoff);
404 hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
405 hdr->e_flags = TO_NATIVE(hdr->e_flags);
406 hdr->e_ehsize = TO_NATIVE(hdr->e_ehsize);
407 hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
408 hdr->e_phnum = TO_NATIVE(hdr->e_phnum);
409 hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
410 hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
411 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
412 sechdrs = (void *)hdr + hdr->e_shoff;
413 info->sechdrs = sechdrs;
415 /* Check if file offset is correct */
416 if (hdr->e_shoff > info->size) {
417 fatal("section header offset=%lu in file '%s' is bigger than "
418 "filesize=%lu\n", (unsigned long)hdr->e_shoff,
419 filename, info->size);
420 return 0;
423 if (hdr->e_shnum == 0) {
425 * There are more than 64k sections,
426 * read count from .sh_size.
427 * note: it doesn't need shndx2secindex()
429 info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
431 else {
432 info->num_sections = hdr->e_shnum;
434 if (hdr->e_shstrndx == SHN_XINDEX) {
435 info->secindex_strings =
436 shndx2secindex(TO_NATIVE(sechdrs[0].sh_link));
438 else {
439 info->secindex_strings = hdr->e_shstrndx;
442 /* Fix endianness in section headers */
443 for (i = 0; i < info->num_sections; i++) {
444 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
445 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
446 sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags);
447 sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr);
448 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
449 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
450 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
451 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info);
452 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
453 sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize);
455 /* Find symbol table. */
456 secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
457 for (i = 1; i < info->num_sections; i++) {
458 const char *secname;
459 int nobits = sechdrs[i].sh_type == SHT_NOBITS;
461 if (!nobits && sechdrs[i].sh_offset > info->size) {
462 fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
463 "sizeof(*hrd)=%zu\n", filename,
464 (unsigned long)sechdrs[i].sh_offset,
465 sizeof(*hdr));
466 return 0;
468 secname = secstrings + sechdrs[i].sh_name;
469 if (strcmp(secname, ".modinfo") == 0) {
470 if (nobits)
471 fatal("%s has NOBITS .modinfo\n", filename);
472 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
473 info->modinfo_len = sechdrs[i].sh_size;
474 } else if (strcmp(secname, "__ksymtab") == 0)
475 info->export_sec = i;
476 else if (strcmp(secname, "__ksymtab_unused") == 0)
477 info->export_unused_sec = i;
478 else if (strcmp(secname, "__ksymtab_gpl") == 0)
479 info->export_gpl_sec = i;
480 else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
481 info->export_unused_gpl_sec = i;
482 else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
483 info->export_gpl_future_sec = i;
485 if (sechdrs[i].sh_type == SHT_SYMTAB) {
486 unsigned int sh_link_idx;
487 symtab_idx = i;
488 info->symtab_start = (void *)hdr +
489 sechdrs[i].sh_offset;
490 info->symtab_stop = (void *)hdr +
491 sechdrs[i].sh_offset + sechdrs[i].sh_size;
492 sh_link_idx = shndx2secindex(sechdrs[i].sh_link);
493 info->strtab = (void *)hdr +
494 sechdrs[sh_link_idx].sh_offset;
497 /* 32bit section no. table? ("more than 64k sections") */
498 if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
499 symtab_shndx_idx = i;
500 info->symtab_shndx_start = (void *)hdr +
501 sechdrs[i].sh_offset;
502 info->symtab_shndx_stop = (void *)hdr +
503 sechdrs[i].sh_offset + sechdrs[i].sh_size;
506 if (!info->symtab_start)
507 fatal("%s has no symtab?\n", filename);
509 /* Fix endianness in symbols */
510 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
511 sym->st_shndx = TO_NATIVE(sym->st_shndx);
512 sym->st_name = TO_NATIVE(sym->st_name);
513 sym->st_value = TO_NATIVE(sym->st_value);
514 sym->st_size = TO_NATIVE(sym->st_size);
517 if (symtab_shndx_idx != ~0U) {
518 Elf32_Word *p;
519 if (symtab_idx !=
520 shndx2secindex(sechdrs[symtab_shndx_idx].sh_link))
521 fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
522 filename,
523 shndx2secindex(sechdrs[symtab_shndx_idx].sh_link),
524 symtab_idx);
525 /* Fix endianness */
526 for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
527 p++)
528 *p = TO_NATIVE(*p);
531 return 1;
534 static void parse_elf_finish(struct elf_info *info)
536 release_file(info->hdr, info->size);
539 static int ignore_undef_symbol(struct elf_info *info, const char *symname)
541 /* ignore __this_module, it will be resolved shortly */
542 if (strcmp(symname, MODULE_SYMBOL_PREFIX "__this_module") == 0)
543 return 1;
544 /* ignore global offset table */
545 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
546 return 1;
547 if (info->hdr->e_machine == EM_PPC)
548 /* Special register function linked on all modules during final link of .ko */
549 if (strncmp(symname, "_restgpr_", sizeof("_restgpr_") - 1) == 0 ||
550 strncmp(symname, "_savegpr_", sizeof("_savegpr_") - 1) == 0 ||
551 strncmp(symname, "_rest32gpr_", sizeof("_rest32gpr_") - 1) == 0 ||
552 strncmp(symname, "_save32gpr_", sizeof("_save32gpr_") - 1) == 0)
553 return 1;
554 if (info->hdr->e_machine == EM_PPC64)
555 /* Special register function linked on all modules during final link of .ko */
556 if (strncmp(symname, "_restgpr0_", sizeof("_restgpr0_") - 1) == 0 ||
557 strncmp(symname, "_savegpr0_", sizeof("_savegpr0_") - 1) == 0)
558 return 1;
559 /* Do not ignore this symbol */
560 return 0;
563 #define CRC_PFX MODULE_SYMBOL_PREFIX "__crc_"
564 #define KSYMTAB_PFX MODULE_SYMBOL_PREFIX "__ksymtab_"
566 static void handle_modversions(struct module *mod, struct elf_info *info,
567 Elf_Sym *sym, const char *symname)
569 unsigned int crc;
570 enum export export = export_from_sec(info, get_secindex(info, sym));
572 switch (sym->st_shndx) {
573 case SHN_COMMON:
574 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
575 break;
576 case SHN_ABS:
577 /* CRC'd symbol */
578 if (strncmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
579 crc = (unsigned int) sym->st_value;
580 sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
581 export);
583 break;
584 case SHN_UNDEF:
585 /* undefined symbol */
586 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
587 ELF_ST_BIND(sym->st_info) != STB_WEAK)
588 break;
589 if (ignore_undef_symbol(info, symname))
590 break;
591 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
592 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
593 /* add compatibility with older glibc */
594 #ifndef STT_SPARC_REGISTER
595 #define STT_SPARC_REGISTER STT_REGISTER
596 #endif
597 if (info->hdr->e_machine == EM_SPARC ||
598 info->hdr->e_machine == EM_SPARCV9) {
599 /* Ignore register directives. */
600 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
601 break;
602 if (symname[0] == '.') {
603 char *munged = strdup(symname);
604 munged[0] = '_';
605 munged[1] = toupper(munged[1]);
606 symname = munged;
609 #endif
611 if (memcmp(symname, MODULE_SYMBOL_PREFIX,
612 strlen(MODULE_SYMBOL_PREFIX)) == 0) {
613 mod->unres =
614 alloc_symbol(symname +
615 strlen(MODULE_SYMBOL_PREFIX),
616 ELF_ST_BIND(sym->st_info) == STB_WEAK,
617 mod->unres);
619 break;
620 default:
621 /* All exported symbols */
622 if (strncmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
623 sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
624 export);
626 if (strcmp(symname, MODULE_SYMBOL_PREFIX "init_module") == 0)
627 mod->has_init = 1;
628 if (strcmp(symname, MODULE_SYMBOL_PREFIX "cleanup_module") == 0)
629 mod->has_cleanup = 1;
630 break;
635 * Parse tag=value strings from .modinfo section
637 static char *next_string(char *string, unsigned long *secsize)
639 /* Skip non-zero chars */
640 while (string[0]) {
641 string++;
642 if ((*secsize)-- <= 1)
643 return NULL;
646 /* Skip any zero padding. */
647 while (!string[0]) {
648 string++;
649 if ((*secsize)-- <= 1)
650 return NULL;
652 return string;
655 static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
656 const char *tag, char *info)
658 char *p;
659 unsigned int taglen = strlen(tag);
660 unsigned long size = modinfo_len;
662 if (info) {
663 size -= info - (char *)modinfo;
664 modinfo = next_string(info, &size);
667 for (p = modinfo; p; p = next_string(p, &size)) {
668 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
669 return p + taglen + 1;
671 return NULL;
674 static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
675 const char *tag)
678 return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
682 * Test if string s ends in string sub
683 * return 0 if match
685 static int strrcmp(const char *s, const char *sub)
687 int slen, sublen;
689 if (!s || !sub)
690 return 1;
692 slen = strlen(s);
693 sublen = strlen(sub);
695 if ((slen == 0) || (sublen == 0))
696 return 1;
698 if (sublen > slen)
699 return 1;
701 return memcmp(s + slen - sublen, sub, sublen);
704 static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
706 if (sym)
707 return elf->strtab + sym->st_name;
708 else
709 return "(unknown)";
712 static const char *sec_name(struct elf_info *elf, int secindex)
714 Elf_Shdr *sechdrs = elf->sechdrs;
715 return (void *)elf->hdr +
716 elf->sechdrs[elf->secindex_strings].sh_offset +
717 sechdrs[secindex].sh_name;
720 static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr)
722 return (void *)elf->hdr +
723 elf->sechdrs[elf->secindex_strings].sh_offset +
724 sechdr->sh_name;
727 /* if sym is empty or point to a string
728 * like ".[0-9]+" then return 1.
729 * This is the optional prefix added by ld to some sections
731 static int number_prefix(const char *sym)
733 if (*sym++ == '\0')
734 return 1;
735 if (*sym != '.')
736 return 0;
737 do {
738 char c = *sym++;
739 if (c < '0' || c > '9')
740 return 0;
741 } while (*sym);
742 return 1;
745 /* The pattern is an array of simple patterns.
746 * "foo" will match an exact string equal to "foo"
747 * "*foo" will match a string that ends with "foo"
748 * "foo*" will match a string that begins with "foo"
749 * "foo$" will match a string equal to "foo" or "foo.1"
750 * where the '1' can be any number including several digits.
751 * The $ syntax is for sections where ld append a dot number
752 * to make section name unique.
754 static int match(const char *sym, const char * const pat[])
756 const char *p;
757 while (*pat) {
758 p = *pat++;
759 const char *endp = p + strlen(p) - 1;
761 /* "*foo" */
762 if (*p == '*') {
763 if (strrcmp(sym, p + 1) == 0)
764 return 1;
766 /* "foo*" */
767 else if (*endp == '*') {
768 if (strncmp(sym, p, strlen(p) - 1) == 0)
769 return 1;
771 /* "foo$" */
772 else if (*endp == '$') {
773 if (strncmp(sym, p, strlen(p) - 1) == 0) {
774 if (number_prefix(sym + strlen(p) - 1))
775 return 1;
778 /* no wildcards */
779 else {
780 if (strcmp(p, sym) == 0)
781 return 1;
784 /* no match */
785 return 0;
788 /* sections that we do not want to do full section mismatch check on */
789 static const char *section_white_list[] =
791 ".comment*",
792 ".debug*",
793 ".GCC-command-line", /* mn10300 */
794 ".mdebug*", /* alpha, score, mips etc. */
795 ".pdr", /* alpha, score, mips etc. */
796 ".stab*",
797 ".note*",
798 ".got*",
799 ".toc*",
800 NULL
804 * This is used to find sections missing the SHF_ALLOC flag.
805 * The cause of this is often a section specified in assembler
806 * without "ax" / "aw".
808 static void check_section(const char *modname, struct elf_info *elf,
809 Elf_Shdr *sechdr)
811 const char *sec = sech_name(elf, sechdr);
813 if (sechdr->sh_type == SHT_PROGBITS &&
814 !(sechdr->sh_flags & SHF_ALLOC) &&
815 !match(sec, section_white_list)) {
816 warn("%s (%s): unexpected non-allocatable section.\n"
817 "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
818 "Note that for example <linux/init.h> contains\n"
819 "section definitions for use in .S files.\n\n",
820 modname, sec);
826 #define ALL_INIT_DATA_SECTIONS \
827 ".init.setup$", ".init.rodata$", \
828 ".devinit.rodata$", ".cpuinit.rodata$", ".meminit.rodata$" \
829 ".init.data$", ".devinit.data$", ".cpuinit.data$", ".meminit.data$"
830 #define ALL_EXIT_DATA_SECTIONS \
831 ".exit.data$", ".devexit.data$", ".cpuexit.data$", ".memexit.data$"
833 #define ALL_INIT_TEXT_SECTIONS \
834 ".init.text$", ".devinit.text$", ".cpuinit.text$", ".meminit.text$"
835 #define ALL_EXIT_TEXT_SECTIONS \
836 ".exit.text$", ".devexit.text$", ".cpuexit.text$", ".memexit.text$"
838 #define ALL_XXXINIT_SECTIONS DEV_INIT_SECTIONS, CPU_INIT_SECTIONS, \
839 MEM_INIT_SECTIONS
840 #define ALL_XXXEXIT_SECTIONS DEV_EXIT_SECTIONS, CPU_EXIT_SECTIONS, \
841 MEM_EXIT_SECTIONS
843 #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
844 #define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
846 #define DATA_SECTIONS ".data$", ".data.rel$"
847 #define TEXT_SECTIONS ".text$"
849 #define INIT_SECTIONS ".init.*"
850 #define DEV_INIT_SECTIONS ".devinit.*"
851 #define CPU_INIT_SECTIONS ".cpuinit.*"
852 #define MEM_INIT_SECTIONS ".meminit.*"
854 #define EXIT_SECTIONS ".exit.*"
855 #define DEV_EXIT_SECTIONS ".devexit.*"
856 #define CPU_EXIT_SECTIONS ".cpuexit.*"
857 #define MEM_EXIT_SECTIONS ".memexit.*"
859 /* init data sections */
860 static const char *init_data_sections[] = { ALL_INIT_DATA_SECTIONS, NULL };
862 /* all init sections */
863 static const char *init_sections[] = { ALL_INIT_SECTIONS, NULL };
865 /* All init and exit sections (code + data) */
866 static const char *init_exit_sections[] =
867 {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
869 /* data section */
870 static const char *data_sections[] = { DATA_SECTIONS, NULL };
873 /* symbols in .data that may refer to init/exit sections */
874 #define DEFAULT_SYMBOL_WHITE_LIST \
875 "*driver", \
876 "*_template", /* scsi uses *_template a lot */ \
877 "*_timer", /* arm uses ops structures named _timer a lot */ \
878 "*_sht", /* scsi also used *_sht to some extent */ \
879 "*_ops", \
880 "*_probe", \
881 "*_probe_one", \
882 "*_console"
884 static const char *head_sections[] = { ".head.text*", NULL };
885 static const char *linker_symbols[] =
886 { "__init_begin", "_sinittext", "_einittext", NULL };
888 enum mismatch {
889 TEXT_TO_ANY_INIT,
890 DATA_TO_ANY_INIT,
891 TEXT_TO_ANY_EXIT,
892 DATA_TO_ANY_EXIT,
893 XXXINIT_TO_SOME_INIT,
894 XXXEXIT_TO_SOME_EXIT,
895 ANY_INIT_TO_ANY_EXIT,
896 ANY_EXIT_TO_ANY_INIT,
897 EXPORT_TO_INIT_EXIT,
900 struct sectioncheck {
901 const char *fromsec[20];
902 const char *tosec[20];
903 enum mismatch mismatch;
904 const char *symbol_white_list[20];
907 const struct sectioncheck sectioncheck[] = {
908 /* Do not reference init/exit code/data from
909 * normal code and data
912 .fromsec = { TEXT_SECTIONS, NULL },
913 .tosec = { ALL_INIT_SECTIONS, NULL },
914 .mismatch = TEXT_TO_ANY_INIT,
915 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
918 .fromsec = { DATA_SECTIONS, NULL },
919 .tosec = { ALL_XXXINIT_SECTIONS, NULL },
920 .mismatch = DATA_TO_ANY_INIT,
921 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
924 .fromsec = { DATA_SECTIONS, NULL },
925 .tosec = { INIT_SECTIONS, NULL },
926 .mismatch = DATA_TO_ANY_INIT,
927 .symbol_white_list = {
928 "*_template", "*_timer", "*_sht", "*_ops",
929 "*_probe", "*_probe_one", "*_console", NULL
933 .fromsec = { TEXT_SECTIONS, NULL },
934 .tosec = { ALL_EXIT_SECTIONS, NULL },
935 .mismatch = TEXT_TO_ANY_EXIT,
936 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
939 .fromsec = { DATA_SECTIONS, NULL },
940 .tosec = { ALL_EXIT_SECTIONS, NULL },
941 .mismatch = DATA_TO_ANY_EXIT,
942 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
944 /* Do not reference init code/data from devinit/cpuinit/meminit code/data */
946 .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
947 .tosec = { INIT_SECTIONS, NULL },
948 .mismatch = XXXINIT_TO_SOME_INIT,
949 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
951 /* Do not reference cpuinit code/data from meminit code/data */
953 .fromsec = { MEM_INIT_SECTIONS, NULL },
954 .tosec = { CPU_INIT_SECTIONS, NULL },
955 .mismatch = XXXINIT_TO_SOME_INIT,
956 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
958 /* Do not reference meminit code/data from cpuinit code/data */
960 .fromsec = { CPU_INIT_SECTIONS, NULL },
961 .tosec = { MEM_INIT_SECTIONS, NULL },
962 .mismatch = XXXINIT_TO_SOME_INIT,
963 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
965 /* Do not reference exit code/data from devexit/cpuexit/memexit code/data */
967 .fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
968 .tosec = { EXIT_SECTIONS, NULL },
969 .mismatch = XXXEXIT_TO_SOME_EXIT,
970 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
972 /* Do not reference cpuexit code/data from memexit code/data */
974 .fromsec = { MEM_EXIT_SECTIONS, NULL },
975 .tosec = { CPU_EXIT_SECTIONS, NULL },
976 .mismatch = XXXEXIT_TO_SOME_EXIT,
977 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
979 /* Do not reference memexit code/data from cpuexit code/data */
981 .fromsec = { CPU_EXIT_SECTIONS, NULL },
982 .tosec = { MEM_EXIT_SECTIONS, NULL },
983 .mismatch = XXXEXIT_TO_SOME_EXIT,
984 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
986 /* Do not use exit code/data from init code */
988 .fromsec = { ALL_INIT_SECTIONS, NULL },
989 .tosec = { ALL_EXIT_SECTIONS, NULL },
990 .mismatch = ANY_INIT_TO_ANY_EXIT,
991 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
993 /* Do not use init code/data from exit code */
995 .fromsec = { ALL_EXIT_SECTIONS, NULL },
996 .tosec = { ALL_INIT_SECTIONS, NULL },
997 .mismatch = ANY_EXIT_TO_ANY_INIT,
998 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1000 /* Do not export init/exit functions or data */
1002 .fromsec = { "__ksymtab*", NULL },
1003 .tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
1004 .mismatch = EXPORT_TO_INIT_EXIT,
1005 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1009 static const struct sectioncheck *section_mismatch(
1010 const char *fromsec, const char *tosec)
1012 int i;
1013 int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
1014 const struct sectioncheck *check = &sectioncheck[0];
1016 for (i = 0; i < elems; i++) {
1017 if (match(fromsec, check->fromsec) &&
1018 match(tosec, check->tosec))
1019 return check;
1020 check++;
1022 return NULL;
1026 * Whitelist to allow certain references to pass with no warning.
1028 * Pattern 1:
1029 * If a module parameter is declared __initdata and permissions=0
1030 * then this is legal despite the warning generated.
1031 * We cannot see value of permissions here, so just ignore
1032 * this pattern.
1033 * The pattern is identified by:
1034 * tosec = .init.data
1035 * fromsec = .data*
1036 * atsym =__param*
1038 * Pattern 2:
1039 * Many drivers utilise a *driver container with references to
1040 * add, remove, probe functions etc.
1041 * These functions may often be marked __devinit and we do not want to
1042 * warn here.
1043 * the pattern is identified by:
1044 * tosec = init or exit section
1045 * fromsec = data section
1046 * atsym = *driver, *_template, *_sht, *_ops, *_probe,
1047 * *probe_one, *_console, *_timer
1049 * Pattern 3:
1050 * Whitelist all references from .head.text to any init section
1052 * Pattern 4:
1053 * Some symbols belong to init section but still it is ok to reference
1054 * these from non-init sections as these symbols don't have any memory
1055 * allocated for them and symbol address and value are same. So even
1056 * if init section is freed, its ok to reference those symbols.
1057 * For ex. symbols marking the init section boundaries.
1058 * This pattern is identified by
1059 * refsymname = __init_begin, _sinittext, _einittext
1062 static int secref_whitelist(const struct sectioncheck *mismatch,
1063 const char *fromsec, const char *fromsym,
1064 const char *tosec, const char *tosym)
1066 /* Check for pattern 1 */
1067 if (match(tosec, init_data_sections) &&
1068 match(fromsec, data_sections) &&
1069 (strncmp(fromsym, "__param", strlen("__param")) == 0))
1070 return 0;
1072 /* Check for pattern 2 */
1073 if (match(tosec, init_exit_sections) &&
1074 match(fromsec, data_sections) &&
1075 match(fromsym, mismatch->symbol_white_list))
1076 return 0;
1078 /* Check for pattern 3 */
1079 if (match(fromsec, head_sections) &&
1080 match(tosec, init_sections))
1081 return 0;
1083 /* Check for pattern 4 */
1084 if (match(tosym, linker_symbols))
1085 return 0;
1087 return 1;
1091 * Find symbol based on relocation record info.
1092 * In some cases the symbol supplied is a valid symbol so
1093 * return refsym. If st_name != 0 we assume this is a valid symbol.
1094 * In other cases the symbol needs to be looked up in the symbol table
1095 * based on section and address.
1096 * **/
1097 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
1098 Elf_Sym *relsym)
1100 Elf_Sym *sym;
1101 Elf_Sym *near = NULL;
1102 Elf64_Sword distance = 20;
1103 Elf64_Sword d;
1104 unsigned int relsym_secindex;
1106 if (relsym->st_name != 0)
1107 return relsym;
1109 relsym_secindex = get_secindex(elf, relsym);
1110 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1111 if (get_secindex(elf, sym) != relsym_secindex)
1112 continue;
1113 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
1114 continue;
1115 if (sym->st_value == addr)
1116 return sym;
1117 /* Find a symbol nearby - addr are maybe negative */
1118 d = sym->st_value - addr;
1119 if (d < 0)
1120 d = addr - sym->st_value;
1121 if (d < distance) {
1122 distance = d;
1123 near = sym;
1126 /* We need a close match */
1127 if (distance < 20)
1128 return near;
1129 else
1130 return NULL;
1133 static inline int is_arm_mapping_symbol(const char *str)
1135 return str[0] == '$' && strchr("atd", str[1])
1136 && (str[2] == '\0' || str[2] == '.');
1140 * If there's no name there, ignore it; likewise, ignore it if it's
1141 * one of the magic symbols emitted used by current ARM tools.
1143 * Otherwise if find_symbols_between() returns those symbols, they'll
1144 * fail the whitelist tests and cause lots of false alarms ... fixable
1145 * only by merging __exit and __init sections into __text, bloating
1146 * the kernel (which is especially evil on embedded platforms).
1148 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1150 const char *name = elf->strtab + sym->st_name;
1152 if (!name || !strlen(name))
1153 return 0;
1154 return !is_arm_mapping_symbol(name);
1158 * Find symbols before or equal addr and after addr - in the section sec.
1159 * If we find two symbols with equal offset prefer one with a valid name.
1160 * The ELF format may have a better way to detect what type of symbol
1161 * it is, but this works for now.
1163 static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1164 const char *sec)
1166 Elf_Sym *sym;
1167 Elf_Sym *near = NULL;
1168 Elf_Addr distance = ~0;
1170 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1171 const char *symsec;
1173 if (is_shndx_special(sym->st_shndx))
1174 continue;
1175 symsec = sec_name(elf, get_secindex(elf, sym));
1176 if (strcmp(symsec, sec) != 0)
1177 continue;
1178 if (!is_valid_name(elf, sym))
1179 continue;
1180 if (sym->st_value <= addr) {
1181 if ((addr - sym->st_value) < distance) {
1182 distance = addr - sym->st_value;
1183 near = sym;
1184 } else if ((addr - sym->st_value) == distance) {
1185 near = sym;
1189 return near;
1193 * Convert a section name to the function/data attribute
1194 * .init.text => __init
1195 * .cpuinit.data => __cpudata
1196 * .memexitconst => __memconst
1197 * etc.
1199 static char *sec2annotation(const char *s)
1201 if (match(s, init_exit_sections)) {
1202 char *p = malloc(20);
1203 char *r = p;
1205 *p++ = '_';
1206 *p++ = '_';
1207 if (*s == '.')
1208 s++;
1209 while (*s && *s != '.')
1210 *p++ = *s++;
1211 *p = '\0';
1212 if (*s == '.')
1213 s++;
1214 if (strstr(s, "rodata") != NULL)
1215 strcat(p, "const ");
1216 else if (strstr(s, "data") != NULL)
1217 strcat(p, "data ");
1218 else
1219 strcat(p, " ");
1220 return r; /* we leak her but we do not care */
1221 } else {
1222 return strdup("");
1226 static int is_function(Elf_Sym *sym)
1228 if (sym)
1229 return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1230 else
1231 return -1;
1235 * Print a warning about a section mismatch.
1236 * Try to find symbols near it so user can find it.
1237 * Check whitelist before warning - it may be a false positive.
1239 static void report_sec_mismatch(const char *modname,
1240 const struct sectioncheck *mismatch,
1241 const char *fromsec,
1242 unsigned long long fromaddr,
1243 const char *fromsym,
1244 int from_is_func,
1245 const char *tosec, const char *tosym,
1246 int to_is_func)
1248 const char *from, *from_p;
1249 const char *to, *to_p;
1250 char *prl_from;
1251 char *prl_to;
1253 switch (from_is_func) {
1254 case 0: from = "variable"; from_p = ""; break;
1255 case 1: from = "function"; from_p = "()"; break;
1256 default: from = "(unknown reference)"; from_p = ""; break;
1258 switch (to_is_func) {
1259 case 0: to = "variable"; to_p = ""; break;
1260 case 1: to = "function"; to_p = "()"; break;
1261 default: to = "(unknown reference)"; to_p = ""; break;
1264 sec_mismatch_count++;
1265 if (!sec_mismatch_verbose)
1266 return;
1268 warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1269 "to the %s %s:%s%s\n",
1270 modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1271 tosym, to_p);
1273 switch (mismatch->mismatch) {
1274 case TEXT_TO_ANY_INIT:
1275 prl_from = sec2annotation(fromsec);
1276 prl_to = sec2annotation(tosec);
1277 fprintf(stderr,
1278 "The function %s%s() references\n"
1279 "the %s %s%s%s.\n"
1280 "This is often because %s lacks a %s\n"
1281 "annotation or the annotation of %s is wrong.\n",
1282 prl_from, fromsym,
1283 to, prl_to, tosym, to_p,
1284 fromsym, prl_to, tosym);
1285 free(prl_from);
1286 free(prl_to);
1287 break;
1288 case DATA_TO_ANY_INIT: {
1289 prl_to = sec2annotation(tosec);
1290 const char *const *s = mismatch->symbol_white_list;
1291 fprintf(stderr,
1292 "The variable %s references\n"
1293 "the %s %s%s%s\n"
1294 "If the reference is valid then annotate the\n"
1295 "variable with __init* or __refdata (see linux/init.h) "
1296 "or name the variable:\n",
1297 fromsym, to, prl_to, tosym, to_p);
1298 while (*s)
1299 fprintf(stderr, "%s, ", *s++);
1300 fprintf(stderr, "\n");
1301 free(prl_to);
1302 break;
1304 case TEXT_TO_ANY_EXIT:
1305 prl_to = sec2annotation(tosec);
1306 fprintf(stderr,
1307 "The function %s() references a %s in an exit section.\n"
1308 "Often the %s %s%s has valid usage outside the exit section\n"
1309 "and the fix is to remove the %sannotation of %s.\n",
1310 fromsym, to, to, tosym, to_p, prl_to, tosym);
1311 free(prl_to);
1312 break;
1313 case DATA_TO_ANY_EXIT: {
1314 prl_to = sec2annotation(tosec);
1315 const char *const *s = mismatch->symbol_white_list;
1316 fprintf(stderr,
1317 "The variable %s references\n"
1318 "the %s %s%s%s\n"
1319 "If the reference is valid then annotate the\n"
1320 "variable with __exit* (see linux/init.h) or "
1321 "name the variable:\n",
1322 fromsym, to, prl_to, tosym, to_p);
1323 while (*s)
1324 fprintf(stderr, "%s, ", *s++);
1325 fprintf(stderr, "\n");
1326 free(prl_to);
1327 break;
1329 case XXXINIT_TO_SOME_INIT:
1330 case XXXEXIT_TO_SOME_EXIT:
1331 prl_from = sec2annotation(fromsec);
1332 prl_to = sec2annotation(tosec);
1333 fprintf(stderr,
1334 "The %s %s%s%s references\n"
1335 "a %s %s%s%s.\n"
1336 "If %s is only used by %s then\n"
1337 "annotate %s with a matching annotation.\n",
1338 from, prl_from, fromsym, from_p,
1339 to, prl_to, tosym, to_p,
1340 tosym, fromsym, tosym);
1341 free(prl_from);
1342 free(prl_to);
1343 break;
1344 case ANY_INIT_TO_ANY_EXIT:
1345 prl_from = sec2annotation(fromsec);
1346 prl_to = sec2annotation(tosec);
1347 fprintf(stderr,
1348 "The %s %s%s%s references\n"
1349 "a %s %s%s%s.\n"
1350 "This is often seen when error handling "
1351 "in the init function\n"
1352 "uses functionality in the exit path.\n"
1353 "The fix is often to remove the %sannotation of\n"
1354 "%s%s so it may be used outside an exit section.\n",
1355 from, prl_from, fromsym, from_p,
1356 to, prl_to, tosym, to_p,
1357 prl_to, tosym, to_p);
1358 free(prl_from);
1359 free(prl_to);
1360 break;
1361 case ANY_EXIT_TO_ANY_INIT:
1362 prl_from = sec2annotation(fromsec);
1363 prl_to = sec2annotation(tosec);
1364 fprintf(stderr,
1365 "The %s %s%s%s references\n"
1366 "a %s %s%s%s.\n"
1367 "This is often seen when error handling "
1368 "in the exit function\n"
1369 "uses functionality in the init path.\n"
1370 "The fix is often to remove the %sannotation of\n"
1371 "%s%s so it may be used outside an init section.\n",
1372 from, prl_from, fromsym, from_p,
1373 to, prl_to, tosym, to_p,
1374 prl_to, tosym, to_p);
1375 free(prl_from);
1376 free(prl_to);
1377 break;
1378 case EXPORT_TO_INIT_EXIT:
1379 prl_to = sec2annotation(tosec);
1380 fprintf(stderr,
1381 "The symbol %s is exported and annotated %s\n"
1382 "Fix this by removing the %sannotation of %s "
1383 "or drop the export.\n",
1384 tosym, prl_to, prl_to, tosym);
1385 free(prl_to);
1386 break;
1388 fprintf(stderr, "\n");
1391 static void check_section_mismatch(const char *modname, struct elf_info *elf,
1392 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1394 const char *tosec;
1395 const struct sectioncheck *mismatch;
1397 tosec = sec_name(elf, get_secindex(elf, sym));
1398 mismatch = section_mismatch(fromsec, tosec);
1399 if (mismatch) {
1400 Elf_Sym *to;
1401 Elf_Sym *from;
1402 const char *tosym;
1403 const char *fromsym;
1405 from = find_elf_symbol2(elf, r->r_offset, fromsec);
1406 fromsym = sym_name(elf, from);
1407 to = find_elf_symbol(elf, r->r_addend, sym);
1408 tosym = sym_name(elf, to);
1410 /* check whitelist - we may ignore it */
1411 if (secref_whitelist(mismatch,
1412 fromsec, fromsym, tosec, tosym)) {
1413 report_sec_mismatch(modname, mismatch,
1414 fromsec, r->r_offset, fromsym,
1415 is_function(from), tosec, tosym,
1416 is_function(to));
1421 static unsigned int *reloc_location(struct elf_info *elf,
1422 Elf_Shdr *sechdr, Elf_Rela *r)
1424 Elf_Shdr *sechdrs = elf->sechdrs;
1425 int section = shndx2secindex(sechdr->sh_info);
1427 return (void *)elf->hdr + sechdrs[section].sh_offset +
1428 r->r_offset - sechdrs[section].sh_addr;
1431 static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1433 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1434 unsigned int *location = reloc_location(elf, sechdr, r);
1436 switch (r_typ) {
1437 case R_386_32:
1438 r->r_addend = TO_NATIVE(*location);
1439 break;
1440 case R_386_PC32:
1441 r->r_addend = TO_NATIVE(*location) + 4;
1442 /* For CONFIG_RELOCATABLE=y */
1443 if (elf->hdr->e_type == ET_EXEC)
1444 r->r_addend += r->r_offset;
1445 break;
1447 return 0;
1450 static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1452 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1454 switch (r_typ) {
1455 case R_ARM_ABS32:
1456 /* From ARM ABI: (S + A) | T */
1457 r->r_addend = (int)(long)
1458 (elf->symtab_start + ELF_R_SYM(r->r_info));
1459 break;
1460 case R_ARM_PC24:
1461 /* From ARM ABI: ((S + A) | T) - P */
1462 r->r_addend = (int)(long)(elf->hdr +
1463 sechdr->sh_offset +
1464 (r->r_offset - sechdr->sh_addr));
1465 break;
1466 default:
1467 return 1;
1469 return 0;
1472 static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1474 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1475 unsigned int *location = reloc_location(elf, sechdr, r);
1476 unsigned int inst;
1478 if (r_typ == R_MIPS_HI16)
1479 return 1; /* skip this */
1480 inst = TO_NATIVE(*location);
1481 switch (r_typ) {
1482 case R_MIPS_LO16:
1483 r->r_addend = inst & 0xffff;
1484 break;
1485 case R_MIPS_26:
1486 r->r_addend = (inst & 0x03ffffff) << 2;
1487 break;
1488 case R_MIPS_32:
1489 r->r_addend = inst;
1490 break;
1492 return 0;
1495 static void section_rela(const char *modname, struct elf_info *elf,
1496 Elf_Shdr *sechdr)
1498 Elf_Sym *sym;
1499 Elf_Rela *rela;
1500 Elf_Rela r;
1501 unsigned int r_sym;
1502 const char *fromsec;
1504 Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1505 Elf_Rela *stop = (void *)start + sechdr->sh_size;
1507 fromsec = sech_name(elf, sechdr);
1508 fromsec += strlen(".rela");
1509 /* if from section (name) is know good then skip it */
1510 if (match(fromsec, section_white_list))
1511 return;
1513 for (rela = start; rela < stop; rela++) {
1514 r.r_offset = TO_NATIVE(rela->r_offset);
1515 #if KERNEL_ELFCLASS == ELFCLASS64
1516 if (elf->hdr->e_machine == EM_MIPS) {
1517 unsigned int r_typ;
1518 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1519 r_sym = TO_NATIVE(r_sym);
1520 r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1521 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1522 } else {
1523 r.r_info = TO_NATIVE(rela->r_info);
1524 r_sym = ELF_R_SYM(r.r_info);
1526 #else
1527 r.r_info = TO_NATIVE(rela->r_info);
1528 r_sym = ELF_R_SYM(r.r_info);
1529 #endif
1530 r.r_addend = TO_NATIVE(rela->r_addend);
1531 sym = elf->symtab_start + r_sym;
1532 /* Skip special sections */
1533 if (is_shndx_special(sym->st_shndx))
1534 continue;
1535 check_section_mismatch(modname, elf, &r, sym, fromsec);
1539 static void section_rel(const char *modname, struct elf_info *elf,
1540 Elf_Shdr *sechdr)
1542 Elf_Sym *sym;
1543 Elf_Rel *rel;
1544 Elf_Rela r;
1545 unsigned int r_sym;
1546 const char *fromsec;
1548 Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1549 Elf_Rel *stop = (void *)start + sechdr->sh_size;
1551 fromsec = sech_name(elf, sechdr);
1552 fromsec += strlen(".rel");
1553 /* if from section (name) is know good then skip it */
1554 if (match(fromsec, section_white_list))
1555 return;
1557 for (rel = start; rel < stop; rel++) {
1558 r.r_offset = TO_NATIVE(rel->r_offset);
1559 #if KERNEL_ELFCLASS == ELFCLASS64
1560 if (elf->hdr->e_machine == EM_MIPS) {
1561 unsigned int r_typ;
1562 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1563 r_sym = TO_NATIVE(r_sym);
1564 r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1565 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1566 } else {
1567 r.r_info = TO_NATIVE(rel->r_info);
1568 r_sym = ELF_R_SYM(r.r_info);
1570 #else
1571 r.r_info = TO_NATIVE(rel->r_info);
1572 r_sym = ELF_R_SYM(r.r_info);
1573 #endif
1574 r.r_addend = 0;
1575 switch (elf->hdr->e_machine) {
1576 case EM_386:
1577 if (addend_386_rel(elf, sechdr, &r))
1578 continue;
1579 break;
1580 case EM_ARM:
1581 if (addend_arm_rel(elf, sechdr, &r))
1582 continue;
1583 break;
1584 case EM_MIPS:
1585 if (addend_mips_rel(elf, sechdr, &r))
1586 continue;
1587 break;
1589 sym = elf->symtab_start + r_sym;
1590 /* Skip special sections */
1591 if (is_shndx_special(sym->st_shndx))
1592 continue;
1593 check_section_mismatch(modname, elf, &r, sym, fromsec);
1598 * A module includes a number of sections that are discarded
1599 * either when loaded or when used as built-in.
1600 * For loaded modules all functions marked __init and all data
1601 * marked __initdata will be discarded when the module has been intialized.
1602 * Likewise for modules used built-in the sections marked __exit
1603 * are discarded because __exit marked function are supposed to be called
1604 * only when a module is unloaded which never happens for built-in modules.
1605 * The check_sec_ref() function traverses all relocation records
1606 * to find all references to a section that reference a section that will
1607 * be discarded and warns about it.
1609 static void check_sec_ref(struct module *mod, const char *modname,
1610 struct elf_info *elf)
1612 int i;
1613 Elf_Shdr *sechdrs = elf->sechdrs;
1615 /* Walk through all sections */
1616 for (i = 0; i < elf->num_sections; i++) {
1617 check_section(modname, elf, &elf->sechdrs[i]);
1618 /* We want to process only relocation sections and not .init */
1619 if (sechdrs[i].sh_type == SHT_RELA)
1620 section_rela(modname, elf, &elf->sechdrs[i]);
1621 else if (sechdrs[i].sh_type == SHT_REL)
1622 section_rel(modname, elf, &elf->sechdrs[i]);
1626 static void read_symbols(char *modname)
1628 const char *symname;
1629 char *version;
1630 char *license;
1631 struct module *mod;
1632 struct elf_info info = { };
1633 Elf_Sym *sym;
1635 if (!parse_elf(&info, modname))
1636 return;
1638 mod = new_module(modname);
1640 /* When there's no vmlinux, don't print warnings about
1641 * unresolved symbols (since there'll be too many ;) */
1642 if (is_vmlinux(modname)) {
1643 have_vmlinux = 1;
1644 mod->skip = 1;
1647 license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1648 if (info.modinfo && !license && !is_vmlinux(modname))
1649 warn("modpost: missing MODULE_LICENSE() in %s\n"
1650 "see include/linux/module.h for "
1651 "more information\n", modname);
1652 while (license) {
1653 if (license_is_gpl_compatible(license))
1654 mod->gpl_compatible = 1;
1655 else {
1656 mod->gpl_compatible = 0;
1657 break;
1659 license = get_next_modinfo(info.modinfo, info.modinfo_len,
1660 "license", license);
1663 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1664 symname = info.strtab + sym->st_name;
1666 handle_modversions(mod, &info, sym, symname);
1667 handle_moddevtable(mod, &info, sym, symname);
1669 if (!is_vmlinux(modname) ||
1670 (is_vmlinux(modname) && vmlinux_section_warnings))
1671 check_sec_ref(mod, modname, &info);
1673 version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1674 if (version)
1675 maybe_frob_rcs_version(modname, version, info.modinfo,
1676 version - (char *)info.hdr);
1677 if (version || (all_versions && !is_vmlinux(modname)))
1678 get_src_version(modname, mod->srcversion,
1679 sizeof(mod->srcversion)-1);
1681 parse_elf_finish(&info);
1683 /* Our trick to get versioning for module struct etc. - it's
1684 * never passed as an argument to an exported function, so
1685 * the automatic versioning doesn't pick it up, but it's really
1686 * important anyhow */
1687 if (modversions)
1688 mod->unres = alloc_symbol("module_layout", 0, mod->unres);
1691 #define SZ 500
1693 /* We first write the generated file into memory using the
1694 * following helper, then compare to the file on disk and
1695 * only update the later if anything changed */
1697 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
1698 const char *fmt, ...)
1700 char tmp[SZ];
1701 int len;
1702 va_list ap;
1704 va_start(ap, fmt);
1705 len = vsnprintf(tmp, SZ, fmt, ap);
1706 buf_write(buf, tmp, len);
1707 va_end(ap);
1710 void buf_write(struct buffer *buf, const char *s, int len)
1712 if (buf->size - buf->pos < len) {
1713 buf->size += len + SZ;
1714 buf->p = realloc(buf->p, buf->size);
1716 strncpy(buf->p + buf->pos, s, len);
1717 buf->pos += len;
1720 static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
1722 const char *e = is_vmlinux(m) ?"":".ko";
1724 switch (exp) {
1725 case export_gpl:
1726 fatal("modpost: GPL-incompatible module %s%s "
1727 "uses GPL-only symbol '%s'\n", m, e, s);
1728 break;
1729 case export_unused_gpl:
1730 fatal("modpost: GPL-incompatible module %s%s "
1731 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
1732 break;
1733 case export_gpl_future:
1734 warn("modpost: GPL-incompatible module %s%s "
1735 "uses future GPL-only symbol '%s'\n", m, e, s);
1736 break;
1737 case export_plain:
1738 case export_unused:
1739 case export_unknown:
1740 /* ignore */
1741 break;
1745 static void check_for_unused(enum export exp, const char *m, const char *s)
1747 const char *e = is_vmlinux(m) ?"":".ko";
1749 switch (exp) {
1750 case export_unused:
1751 case export_unused_gpl:
1752 warn("modpost: module %s%s "
1753 "uses symbol '%s' marked UNUSED\n", m, e, s);
1754 break;
1755 default:
1756 /* ignore */
1757 break;
1761 static void check_exports(struct module *mod)
1763 struct symbol *s, *exp;
1765 for (s = mod->unres; s; s = s->next) {
1766 const char *basename;
1767 exp = find_symbol(s->name);
1768 if (!exp || exp->module == mod)
1769 continue;
1770 basename = strrchr(mod->name, '/');
1771 if (basename)
1772 basename++;
1773 else
1774 basename = mod->name;
1775 if (!mod->gpl_compatible)
1776 check_for_gpl_usage(exp->export, basename, exp->name);
1777 check_for_unused(exp->export, basename, exp->name);
1782 * Header for the generated file
1784 static void add_header(struct buffer *b, struct module *mod)
1786 buf_printf(b, "#include <linux/module.h>\n");
1787 buf_printf(b, "#include <linux/vermagic.h>\n");
1788 buf_printf(b, "#include <linux/compiler.h>\n");
1789 buf_printf(b, "\n");
1790 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
1791 buf_printf(b, "\n");
1792 buf_printf(b, "struct module __this_module\n");
1793 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
1794 buf_printf(b, " .name = KBUILD_MODNAME,\n");
1795 if (mod->has_init)
1796 buf_printf(b, " .init = init_module,\n");
1797 if (mod->has_cleanup)
1798 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
1799 " .exit = cleanup_module,\n"
1800 "#endif\n");
1801 buf_printf(b, " .arch = MODULE_ARCH_INIT,\n");
1802 buf_printf(b, "};\n");
1805 static void add_staging_flag(struct buffer *b, const char *name)
1807 static const char *staging_dir = "drivers/staging";
1809 if (strncmp(staging_dir, name, strlen(staging_dir)) == 0)
1810 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
1814 * Record CRCs for unresolved symbols
1816 static int add_versions(struct buffer *b, struct module *mod)
1818 struct symbol *s, *exp;
1819 int err = 0;
1821 for (s = mod->unres; s; s = s->next) {
1822 exp = find_symbol(s->name);
1823 if (!exp || exp->module == mod) {
1824 if (have_vmlinux && !s->weak) {
1825 if (warn_unresolved) {
1826 warn("\"%s\" [%s.ko] undefined!\n",
1827 s->name, mod->name);
1828 } else {
1829 merror("\"%s\" [%s.ko] undefined!\n",
1830 s->name, mod->name);
1831 err = 1;
1834 continue;
1836 s->module = exp->module;
1837 s->crc_valid = exp->crc_valid;
1838 s->crc = exp->crc;
1841 if (!modversions)
1842 return err;
1844 buf_printf(b, "\n");
1845 buf_printf(b, "static const struct modversion_info ____versions[]\n");
1846 buf_printf(b, "__used\n");
1847 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
1849 for (s = mod->unres; s; s = s->next) {
1850 if (!s->module)
1851 continue;
1852 if (!s->crc_valid) {
1853 warn("\"%s\" [%s.ko] has no CRC!\n",
1854 s->name, mod->name);
1855 continue;
1857 buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name);
1860 buf_printf(b, "};\n");
1862 return err;
1865 static void add_depends(struct buffer *b, struct module *mod,
1866 struct module *modules)
1868 struct symbol *s;
1869 struct module *m;
1870 int first = 1;
1872 for (m = modules; m; m = m->next)
1873 m->seen = is_vmlinux(m->name);
1875 buf_printf(b, "\n");
1876 buf_printf(b, "static const char __module_depends[]\n");
1877 buf_printf(b, "__used\n");
1878 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
1879 buf_printf(b, "\"depends=");
1880 for (s = mod->unres; s; s = s->next) {
1881 const char *p;
1882 if (!s->module)
1883 continue;
1885 if (s->module->seen)
1886 continue;
1888 s->module->seen = 1;
1889 p = strrchr(s->module->name, '/');
1890 if (p)
1891 p++;
1892 else
1893 p = s->module->name;
1894 buf_printf(b, "%s%s", first ? "" : ",", p);
1895 first = 0;
1897 buf_printf(b, "\";\n");
1900 static void add_srcversion(struct buffer *b, struct module *mod)
1902 if (mod->srcversion[0]) {
1903 buf_printf(b, "\n");
1904 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
1905 mod->srcversion);
1909 static void write_if_changed(struct buffer *b, const char *fname)
1911 char *tmp;
1912 FILE *file;
1913 struct stat st;
1915 file = fopen(fname, "r");
1916 if (!file)
1917 goto write;
1919 if (fstat(fileno(file), &st) < 0)
1920 goto close_write;
1922 if (st.st_size != b->pos)
1923 goto close_write;
1925 tmp = NOFAIL(malloc(b->pos));
1926 if (fread(tmp, 1, b->pos, file) != b->pos)
1927 goto free_write;
1929 if (memcmp(tmp, b->p, b->pos) != 0)
1930 goto free_write;
1932 free(tmp);
1933 fclose(file);
1934 return;
1936 free_write:
1937 free(tmp);
1938 close_write:
1939 fclose(file);
1940 write:
1941 file = fopen(fname, "w");
1942 if (!file) {
1943 perror(fname);
1944 exit(1);
1946 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
1947 perror(fname);
1948 exit(1);
1950 fclose(file);
1953 /* parse Module.symvers file. line format:
1954 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
1956 static void read_dump(const char *fname, unsigned int kernel)
1958 unsigned long size, pos = 0;
1959 void *file = grab_file(fname, &size);
1960 char *line;
1962 if (!file)
1963 /* No symbol versions, silently ignore */
1964 return;
1966 while ((line = get_next_line(&pos, file, size))) {
1967 char *symname, *modname, *d, *export, *end;
1968 unsigned int crc;
1969 struct module *mod;
1970 struct symbol *s;
1972 if (!(symname = strchr(line, '\t')))
1973 goto fail;
1974 *symname++ = '\0';
1975 if (!(modname = strchr(symname, '\t')))
1976 goto fail;
1977 *modname++ = '\0';
1978 if ((export = strchr(modname, '\t')) != NULL)
1979 *export++ = '\0';
1980 if (export && ((end = strchr(export, '\t')) != NULL))
1981 *end = '\0';
1982 crc = strtoul(line, &d, 16);
1983 if (*symname == '\0' || *modname == '\0' || *d != '\0')
1984 goto fail;
1985 mod = find_module(modname);
1986 if (!mod) {
1987 if (is_vmlinux(modname))
1988 have_vmlinux = 1;
1989 mod = new_module(modname);
1990 mod->skip = 1;
1992 s = sym_add_exported(symname, mod, export_no(export));
1993 s->kernel = kernel;
1994 s->preloaded = 1;
1995 sym_update_crc(symname, mod, crc, export_no(export));
1997 return;
1998 fail:
1999 fatal("parse error in symbol dump file\n");
2002 /* For normal builds always dump all symbols.
2003 * For external modules only dump symbols
2004 * that are not read from kernel Module.symvers.
2006 static int dump_sym(struct symbol *sym)
2008 if (!external_module)
2009 return 1;
2010 if (sym->vmlinux || sym->kernel)
2011 return 0;
2012 return 1;
2015 static void write_dump(const char *fname)
2017 struct buffer buf = { };
2018 struct symbol *symbol;
2019 int n;
2021 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
2022 symbol = symbolhash[n];
2023 while (symbol) {
2024 if (dump_sym(symbol))
2025 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
2026 symbol->crc, symbol->name,
2027 symbol->module->name,
2028 export_str(symbol->export));
2029 symbol = symbol->next;
2032 write_if_changed(&buf, fname);
2035 struct ext_sym_list {
2036 struct ext_sym_list *next;
2037 const char *file;
2040 int main(int argc, char **argv)
2042 struct module *mod;
2043 struct buffer buf = { };
2044 char *kernel_read = NULL, *module_read = NULL;
2045 char *dump_write = NULL;
2046 int opt;
2047 int err;
2048 struct ext_sym_list *extsym_iter;
2049 struct ext_sym_list *extsym_start = NULL;
2051 while ((opt = getopt(argc, argv, "i:I:e:cmsSo:awM:K:")) != -1) {
2052 switch (opt) {
2053 case 'i':
2054 kernel_read = optarg;
2055 break;
2056 case 'I':
2057 module_read = optarg;
2058 external_module = 1;
2059 break;
2060 case 'c':
2061 cross_build = 1;
2062 break;
2063 case 'e':
2064 external_module = 1;
2065 extsym_iter =
2066 NOFAIL(malloc(sizeof(*extsym_iter)));
2067 extsym_iter->next = extsym_start;
2068 extsym_iter->file = optarg;
2069 extsym_start = extsym_iter;
2070 break;
2071 case 'm':
2072 modversions = 1;
2073 break;
2074 case 'o':
2075 dump_write = optarg;
2076 break;
2077 case 'a':
2078 all_versions = 1;
2079 break;
2080 case 's':
2081 vmlinux_section_warnings = 0;
2082 break;
2083 case 'S':
2084 sec_mismatch_verbose = 0;
2085 break;
2086 case 'w':
2087 warn_unresolved = 1;
2088 break;
2089 default:
2090 exit(1);
2094 if (kernel_read)
2095 read_dump(kernel_read, 1);
2096 if (module_read)
2097 read_dump(module_read, 0);
2098 while (extsym_start) {
2099 read_dump(extsym_start->file, 0);
2100 extsym_iter = extsym_start->next;
2101 free(extsym_start);
2102 extsym_start = extsym_iter;
2105 while (optind < argc)
2106 read_symbols(argv[optind++]);
2108 for (mod = modules; mod; mod = mod->next) {
2109 if (mod->skip)
2110 continue;
2111 check_exports(mod);
2114 err = 0;
2116 for (mod = modules; mod; mod = mod->next) {
2117 char fname[strlen(mod->name) + 10];
2119 if (mod->skip)
2120 continue;
2122 buf.pos = 0;
2124 add_header(&buf, mod);
2125 add_staging_flag(&buf, mod->name);
2126 err |= add_versions(&buf, mod);
2127 add_depends(&buf, mod, modules);
2128 add_moddevtable(&buf, mod);
2129 add_srcversion(&buf, mod);
2131 sprintf(fname, "%s.mod.c", mod->name);
2132 write_if_changed(&buf, fname);
2135 if (dump_write)
2136 write_dump(dump_write);
2137 if (sec_mismatch_count && !sec_mismatch_verbose)
2138 warn("modpost: Found %d section mismatch(es).\n"
2139 "To see full details build your kernel with:\n"
2140 "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n",
2141 sec_mismatch_count);
2143 return err;