projects/linux·blob v2.6.35 · refs

2066 lines · 52.8 KiB

1/* Postprocess module symbol versions
2 *
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
7 *
8 * This software may be used and distributed according to the terms
9 * of the GNU General Public License, incorporated herein by reference.
10 *
11 * Usage: modpost vmlinux module1.o module2.o ...
12 */
13
14#define _GNU_SOURCE
15#include <stdio.h>
16#include <ctype.h>
17#include "modpost.h"
18#include "../../include/generated/autoconf.h"
19#include "../../include/linux/license.h"
20
21/* Some toolchains use a `_' prefix for all user symbols. */
22#ifdef CONFIG_SYMBOL_PREFIX
23#define MODULE_SYMBOL_PREFIX CONFIG_SYMBOL_PREFIX
24#else
25#define MODULE_SYMBOL_PREFIX ""
26#endif
27
28
29/* Are we using CONFIG_MODVERSIONS? */
30int modversions = 0;
31/* Warn about undefined symbols? (do so if we have vmlinux) */
32int have_vmlinux = 0;
33/* Is CONFIG_MODULE_SRCVERSION_ALL set? */
34static int all_versions = 0;
35/* If we are modposting external module set to 1 */
36static int external_module = 0;
37/* Warn about section mismatch in vmlinux if set to 1 */
38static int vmlinux_section_warnings = 1;
39/* Only warn about unresolved symbols */
40static int warn_unresolved = 0;
41/* How a symbol is exported */
42static int sec_mismatch_count = 0;
43static int sec_mismatch_verbose = 1;
44
45enum export {
46 export_plain, export_unused, export_gpl,
47 export_unused_gpl, export_gpl_future, export_unknown
48};
49
50#define PRINTF __attribute__ ((format (printf, 1, 2)))
51
52PRINTF void fatal(const char *fmt, ...)
53{
54 va_list arglist;
55
56 fprintf(stderr, "FATAL: ");
57
58 va_start(arglist, fmt);
59 vfprintf(stderr, fmt, arglist);
60 va_end(arglist);
61
62 exit(1);
63}
64
65PRINTF void warn(const char *fmt, ...)
66{
67 va_list arglist;
68
69 fprintf(stderr, "WARNING: ");
70
71 va_start(arglist, fmt);
72 vfprintf(stderr, fmt, arglist);
73 va_end(arglist);
74}
75
76PRINTF void merror(const char *fmt, ...)
77{
78 va_list arglist;
79
80 fprintf(stderr, "ERROR: ");
81
82 va_start(arglist, fmt);
83 vfprintf(stderr, fmt, arglist);
84 va_end(arglist);
85}
86
87static int is_vmlinux(const char *modname)
88{
89 const char *myname;
90
91 myname = strrchr(modname, '/');
92 if (myname)
93 myname++;
94 else
95 myname = modname;
96
97 return (strcmp(myname, "vmlinux") == 0) ||
98 (strcmp(myname, "vmlinux.o") == 0);
99}
100
101void *do_nofail(void *ptr, const char *expr)
102{
103 if (!ptr)
104 fatal("modpost: Memory allocation failure: %s.\n", expr);
105
106 return ptr;
107}
108
109/* A list of all modules we processed */
110static struct module *modules;
111
112static struct module *find_module(char *modname)
113{
114 struct module *mod;
115
116 for (mod = modules; mod; mod = mod->next)
117 if (strcmp(mod->name, modname) == 0)
118 break;
119 return mod;
120}
121
122static struct module *new_module(char *modname)
123{
124 struct module *mod;
125 char *p, *s;
126
127 mod = NOFAIL(malloc(sizeof(*mod)));
128 memset(mod, 0, sizeof(*mod));
129 p = NOFAIL(strdup(modname));
130
131 /* strip trailing .o */
132 s = strrchr(p, '.');
133 if (s != NULL)
134 if (strcmp(s, ".o") == 0)
135 *s = '\0';
136
137 /* add to list */
138 mod->name = p;
139 mod->gpl_compatible = -1;
140 mod->next = modules;
141 modules = mod;
142
143 return mod;
144}
145
146/* A hash of all exported symbols,
147 * struct symbol is also used for lists of unresolved symbols */
148
149#define SYMBOL_HASH_SIZE 1024
150
151struct symbol {
152 struct symbol *next;
153 struct module *module;
154 unsigned int crc;
155 int crc_valid;
156 unsigned int weak:1;
157 unsigned int vmlinux:1; /* 1 if symbol is defined in vmlinux */
158 unsigned int kernel:1; /* 1 if symbol is from kernel
159 * (only for external modules) **/
160 unsigned int preloaded:1; /* 1 if symbol from Module.symvers */
161 enum export export; /* Type of export */
162 char name[0];
163};
164
165static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
166
167/* This is based on the hash agorithm from gdbm, via tdb */
168static inline unsigned int tdb_hash(const char *name)
169{
170 unsigned value; /* Used to compute the hash value. */
171 unsigned i; /* Used to cycle through random values. */
172
173 /* Set the initial value from the key size. */
174 for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
175 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
176
177 return (1103515243 * value + 12345);
178}
179
180/**
181 * Allocate a new symbols for use in the hash of exported symbols or
182 * the list of unresolved symbols per module
183 **/
184static struct symbol *alloc_symbol(const char *name, unsigned int weak,
185 struct symbol *next)
186{
187 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
188
189 memset(s, 0, sizeof(*s));
190 strcpy(s->name, name);
191 s->weak = weak;
192 s->next = next;
193 return s;
194}
195
196/* For the hash of exported symbols */
197static struct symbol *new_symbol(const char *name, struct module *module,
198 enum export export)
199{
200 unsigned int hash;
201 struct symbol *new;
202
203 hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
204 new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
205 new->module = module;
206 new->export = export;
207 return new;
208}
209
210static struct symbol *find_symbol(const char *name)
211{
212 struct symbol *s;
213
214 /* For our purposes, .foo matches foo. PPC64 needs this. */
215 if (name[0] == '.')
216 name++;
217
218 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
219 if (strcmp(s->name, name) == 0)
220 return s;
221 }
222 return NULL;
223}
224
225static struct {
226 const char *str;
227 enum export export;
228} export_list[] = {
229 { .str = "EXPORT_SYMBOL", .export = export_plain },
230 { .str = "EXPORT_UNUSED_SYMBOL", .export = export_unused },
231 { .str = "EXPORT_SYMBOL_GPL", .export = export_gpl },
232 { .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
233 { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
234 { .str = "(unknown)", .export = export_unknown },
235};
236
237
238static const char *export_str(enum export ex)
239{
240 return export_list[ex].str;
241}
242
243static enum export export_no(const char *s)
244{
245 int i;
246
247 if (!s)
248 return export_unknown;
249 for (i = 0; export_list[i].export != export_unknown; i++) {
250 if (strcmp(export_list[i].str, s) == 0)
251 return export_list[i].export;
252 }
253 return export_unknown;
254}
255
256static enum export export_from_sec(struct elf_info *elf, Elf_Section sec)
257{
258 if (sec == elf->export_sec)
259 return export_plain;
260 else if (sec == elf->export_unused_sec)
261 return export_unused;
262 else if (sec == elf->export_gpl_sec)
263 return export_gpl;
264 else if (sec == elf->export_unused_gpl_sec)
265 return export_unused_gpl;
266 else if (sec == elf->export_gpl_future_sec)
267 return export_gpl_future;
268 else
269 return export_unknown;
270}
271
272/**
273 * Add an exported symbol - it may have already been added without a
274 * CRC, in this case just update the CRC
275 **/
276static struct symbol *sym_add_exported(const char *name, struct module *mod,
277 enum export export)
278{
279 struct symbol *s = find_symbol(name);
280
281 if (!s) {
282 s = new_symbol(name, mod, export);
283 } else {
284 if (!s->preloaded) {
285 warn("%s: '%s' exported twice. Previous export "
286 "was in %s%s\n", mod->name, name,
287 s->module->name,
288 is_vmlinux(s->module->name) ?"":".ko");
289 } else {
290 /* In case Modules.symvers was out of date */
291 s->module = mod;
292 }
293 }
294 s->preloaded = 0;
295 s->vmlinux = is_vmlinux(mod->name);
296 s->kernel = 0;
297 s->export = export;
298 return s;
299}
300
301static void sym_update_crc(const char *name, struct module *mod,
302 unsigned int crc, enum export export)
303{
304 struct symbol *s = find_symbol(name);
305
306 if (!s)
307 s = new_symbol(name, mod, export);
308 s->crc = crc;
309 s->crc_valid = 1;
310}
311
312void *grab_file(const char *filename, unsigned long *size)
313{
314 struct stat st;
315 void *map;
316 int fd;
317
318 fd = open(filename, O_RDONLY);
319 if (fd < 0 || fstat(fd, &st) != 0)
320 return NULL;
321
322 *size = st.st_size;
323 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
324 close(fd);
325
326 if (map == MAP_FAILED)
327 return NULL;
328 return map;
329}
330
331/**
332 * Return a copy of the next line in a mmap'ed file.
333 * spaces in the beginning of the line is trimmed away.
334 * Return a pointer to a static buffer.
335 **/
336char *get_next_line(unsigned long *pos, void *file, unsigned long size)
337{
338 static char line[4096];
339 int skip = 1;
340 size_t len = 0;
341 signed char *p = (signed char *)file + *pos;
342 char *s = line;
343
344 for (; *pos < size ; (*pos)++) {
345 if (skip && isspace(*p)) {
346 p++;
347 continue;
348 }
349 skip = 0;
350 if (*p != '\n' && (*pos < size)) {
351 len++;
352 *s++ = *p++;
353 if (len > 4095)
354 break; /* Too long, stop */
355 } else {
356 /* End of string */
357 *s = '\0';
358 return line;
359 }
360 }
361 /* End of buffer */
362 return NULL;
363}
364
365void release_file(void *file, unsigned long size)
366{
367 munmap(file, size);
368}
369
370static int parse_elf(struct elf_info *info, const char *filename)
371{
372 unsigned int i;
373 Elf_Ehdr *hdr;
374 Elf_Shdr *sechdrs;
375 Elf_Sym *sym;
376
377 hdr = grab_file(filename, &info->size);
378 if (!hdr) {
379 perror(filename);
380 exit(1);
381 }
382 info->hdr = hdr;
383 if (info->size < sizeof(*hdr)) {
384 /* file too small, assume this is an empty .o file */
385 return 0;
386 }
387 /* Is this a valid ELF file? */
388 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
389 (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
390 (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
391 (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
392 /* Not an ELF file - silently ignore it */
393 return 0;
394 }
395 /* Fix endianness in ELF header */
396 hdr->e_type = TO_NATIVE(hdr->e_type);
397 hdr->e_machine = TO_NATIVE(hdr->e_machine);
398 hdr->e_version = TO_NATIVE(hdr->e_version);
399 hdr->e_entry = TO_NATIVE(hdr->e_entry);
400 hdr->e_phoff = TO_NATIVE(hdr->e_phoff);
401 hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
402 hdr->e_flags = TO_NATIVE(hdr->e_flags);
403 hdr->e_ehsize = TO_NATIVE(hdr->e_ehsize);
404 hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
405 hdr->e_phnum = TO_NATIVE(hdr->e_phnum);
406 hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
407 hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
408 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
409 sechdrs = (void *)hdr + hdr->e_shoff;
410 info->sechdrs = sechdrs;
411
412 /* Check if file offset is correct */
413 if (hdr->e_shoff > info->size) {
414 fatal("section header offset=%lu in file '%s' is bigger than "
415 "filesize=%lu\n", (unsigned long)hdr->e_shoff,
416 filename, info->size);
417 return 0;
418 }
419
420 /* Fix endianness in section headers */
421 for (i = 0; i < hdr->e_shnum; i++) {
422 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
423 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
424 sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags);
425 sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr);
426 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
427 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
428 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
429 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info);
430 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
431 sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize);
432 }
433 /* Find symbol table. */
434 for (i = 1; i < hdr->e_shnum; i++) {
435 const char *secstrings
436 = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
437 const char *secname;
438 int nobits = sechdrs[i].sh_type == SHT_NOBITS;
439
440 if (!nobits && sechdrs[i].sh_offset > info->size) {
441 fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
442 "sizeof(*hrd)=%zu\n", filename,
443 (unsigned long)sechdrs[i].sh_offset,
444 sizeof(*hdr));
445 return 0;
446 }
447 secname = secstrings + sechdrs[i].sh_name;
448 if (strcmp(secname, ".modinfo") == 0) {
449 if (nobits)
450 fatal("%s has NOBITS .modinfo\n", filename);
451 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
452 info->modinfo_len = sechdrs[i].sh_size;
453 } else if (strcmp(secname, "__ksymtab") == 0)
454 info->export_sec = i;
455 else if (strcmp(secname, "__ksymtab_unused") == 0)
456 info->export_unused_sec = i;
457 else if (strcmp(secname, "__ksymtab_gpl") == 0)
458 info->export_gpl_sec = i;
459 else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
460 info->export_unused_gpl_sec = i;
461 else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
462 info->export_gpl_future_sec = i;
463
464 if (sechdrs[i].sh_type != SHT_SYMTAB)
465 continue;
466
467 info->symtab_start = (void *)hdr + sechdrs[i].sh_offset;
468 info->symtab_stop = (void *)hdr + sechdrs[i].sh_offset
469 + sechdrs[i].sh_size;
470 info->strtab = (void *)hdr +
471 sechdrs[sechdrs[i].sh_link].sh_offset;
472 }
473 if (!info->symtab_start)
474 fatal("%s has no symtab?\n", filename);
475
476 /* Fix endianness in symbols */
477 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
478 sym->st_shndx = TO_NATIVE(sym->st_shndx);
479 sym->st_name = TO_NATIVE(sym->st_name);
480 sym->st_value = TO_NATIVE(sym->st_value);
481 sym->st_size = TO_NATIVE(sym->st_size);
482 }
483 return 1;
484}
485
486static void parse_elf_finish(struct elf_info *info)
487{
488 release_file(info->hdr, info->size);
489}
490
491static int ignore_undef_symbol(struct elf_info *info, const char *symname)
492{
493 /* ignore __this_module, it will be resolved shortly */
494 if (strcmp(symname, MODULE_SYMBOL_PREFIX "__this_module") == 0)
495 return 1;
496 /* ignore global offset table */
497 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
498 return 1;
499 if (info->hdr->e_machine == EM_PPC)
500 /* Special register function linked on all modules during final link of .ko */
501 if (strncmp(symname, "_restgpr_", sizeof("_restgpr_") - 1) == 0 ||
502 strncmp(symname, "_savegpr_", sizeof("_savegpr_") - 1) == 0 ||
503 strncmp(symname, "_rest32gpr_", sizeof("_rest32gpr_") - 1) == 0 ||
504 strncmp(symname, "_save32gpr_", sizeof("_save32gpr_") - 1) == 0)
505 return 1;
506 if (info->hdr->e_machine == EM_PPC64)
507 /* Special register function linked on all modules during final link of .ko */
508 if (strncmp(symname, "_restgpr0_", sizeof("_restgpr0_") - 1) == 0 ||
509 strncmp(symname, "_savegpr0_", sizeof("_savegpr0_") - 1) == 0)
510 return 1;
511 /* Do not ignore this symbol */
512 return 0;
513}
514
515#define CRC_PFX MODULE_SYMBOL_PREFIX "__crc_"
516#define KSYMTAB_PFX MODULE_SYMBOL_PREFIX "__ksymtab_"
517
518static void handle_modversions(struct module *mod, struct elf_info *info,
519 Elf_Sym *sym, const char *symname)
520{
521 unsigned int crc;
522 enum export export = export_from_sec(info, sym->st_shndx);
523
524 switch (sym->st_shndx) {
525 case SHN_COMMON:
526 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
527 break;
528 case SHN_ABS:
529 /* CRC'd symbol */
530 if (strncmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
531 crc = (unsigned int) sym->st_value;
532 sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
533 export);
534 }
535 break;
536 case SHN_UNDEF:
537 /* undefined symbol */
538 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
539 ELF_ST_BIND(sym->st_info) != STB_WEAK)
540 break;
541 if (ignore_undef_symbol(info, symname))
542 break;
543/* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
544#if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
545/* add compatibility with older glibc */
546#ifndef STT_SPARC_REGISTER
547#define STT_SPARC_REGISTER STT_REGISTER
548#endif
549 if (info->hdr->e_machine == EM_SPARC ||
550 info->hdr->e_machine == EM_SPARCV9) {
551 /* Ignore register directives. */
552 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
553 break;
554 if (symname[0] == '.') {
555 char *munged = strdup(symname);
556 munged[0] = '_';
557 munged[1] = toupper(munged[1]);
558 symname = munged;
559 }
560 }
561#endif
562
563 if (memcmp(symname, MODULE_SYMBOL_PREFIX,
564 strlen(MODULE_SYMBOL_PREFIX)) == 0) {
565 mod->unres =
566 alloc_symbol(symname +
567 strlen(MODULE_SYMBOL_PREFIX),
568 ELF_ST_BIND(sym->st_info) == STB_WEAK,
569 mod->unres);
570 }
571 break;
572 default:
573 /* All exported symbols */
574 if (strncmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
575 sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
576 export);
577 }
578 if (strcmp(symname, MODULE_SYMBOL_PREFIX "init_module") == 0)
579 mod->has_init = 1;
580 if (strcmp(symname, MODULE_SYMBOL_PREFIX "cleanup_module") == 0)
581 mod->has_cleanup = 1;
582 break;
583 }
584}
585
586/**
587 * Parse tag=value strings from .modinfo section
588 **/
589static char *next_string(char *string, unsigned long *secsize)
590{
591 /* Skip non-zero chars */
592 while (string[0]) {
593 string++;
594 if ((*secsize)-- <= 1)
595 return NULL;
596 }
597
598 /* Skip any zero padding. */
599 while (!string[0]) {
600 string++;
601 if ((*secsize)-- <= 1)
602 return NULL;
603 }
604 return string;
605}
606
607static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
608 const char *tag, char *info)
609{
610 char *p;
611 unsigned int taglen = strlen(tag);
612 unsigned long size = modinfo_len;
613
614 if (info) {
615 size -= info - (char *)modinfo;
616 modinfo = next_string(info, &size);
617 }
618
619 for (p = modinfo; p; p = next_string(p, &size)) {
620 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
621 return p + taglen + 1;
622 }
623 return NULL;
624}
625
626static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
627 const char *tag)
628
629{
630 return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
631}
632
633/**
634 * Test if string s ends in string sub
635 * return 0 if match
636 **/
637static int strrcmp(const char *s, const char *sub)
638{
639 int slen, sublen;
640
641 if (!s || !sub)
642 return 1;
643
644 slen = strlen(s);
645 sublen = strlen(sub);
646
647 if ((slen == 0) || (sublen == 0))
648 return 1;
649
650 if (sublen > slen)
651 return 1;
652
653 return memcmp(s + slen - sublen, sub, sublen);
654}
655
656static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
657{
658 if (sym)
659 return elf->strtab + sym->st_name;
660 else
661 return "(unknown)";
662}
663
664static const char *sec_name(struct elf_info *elf, int shndx)
665{
666 Elf_Shdr *sechdrs = elf->sechdrs;
667 return (void *)elf->hdr +
668 elf->sechdrs[elf->hdr->e_shstrndx].sh_offset +
669 sechdrs[shndx].sh_name;
670}
671
672static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr)
673{
674 return (void *)elf->hdr +
675 elf->sechdrs[elf->hdr->e_shstrndx].sh_offset +
676 sechdr->sh_name;
677}
678
679/* if sym is empty or point to a string
680 * like ".[0-9]+" then return 1.
681 * This is the optional prefix added by ld to some sections
682 */
683static int number_prefix(const char *sym)
684{
685 if (*sym++ == '\0')
686 return 1;
687 if (*sym != '.')
688 return 0;
689 do {
690 char c = *sym++;
691 if (c < '0' || c > '9')
692 return 0;
693 } while (*sym);
694 return 1;
695}
696
697/* The pattern is an array of simple patterns.
698 * "foo" will match an exact string equal to "foo"
699 * "*foo" will match a string that ends with "foo"
700 * "foo*" will match a string that begins with "foo"
701 * "foo$" will match a string equal to "foo" or "foo.1"
702 * where the '1' can be any number including several digits.
703 * The $ syntax is for sections where ld append a dot number
704 * to make section name unique.
705 */
706static int match(const char *sym, const char * const pat[])
707{
708 const char *p;
709 while (*pat) {
710 p = *pat++;
711 const char *endp = p + strlen(p) - 1;
712
713 /* "*foo" */
714 if (*p == '*') {
715 if (strrcmp(sym, p + 1) == 0)
716 return 1;
717 }
718 /* "foo*" */
719 else if (*endp == '*') {
720 if (strncmp(sym, p, strlen(p) - 1) == 0)
721 return 1;
722 }
723 /* "foo$" */
724 else if (*endp == '$') {
725 if (strncmp(sym, p, strlen(p) - 1) == 0) {
726 if (number_prefix(sym + strlen(p) - 1))
727 return 1;
728 }
729 }
730 /* no wildcards */
731 else {
732 if (strcmp(p, sym) == 0)
733 return 1;
734 }
735 }
736 /* no match */
737 return 0;
738}
739
740/* sections that we do not want to do full section mismatch check on */
741static const char *section_white_list[] =
742{
743 ".comment*",
744 ".debug*",
745 ".mdebug*", /* alpha, score, mips etc. */
746 ".pdr", /* alpha, score, mips etc. */
747 ".stab*",
748 ".note*",
749 ".got*",
750 ".toc*",
751 NULL
752};
753
754/*
755 * This is used to find sections missing the SHF_ALLOC flag.
756 * The cause of this is often a section specified in assembler
757 * without "ax" / "aw".
758 */
759static void check_section(const char *modname, struct elf_info *elf,
760 Elf_Shdr *sechdr)
761{
762 const char *sec = sech_name(elf, sechdr);
763
764 if (sechdr->sh_type == SHT_PROGBITS &&
765 !(sechdr->sh_flags & SHF_ALLOC) &&
766 !match(sec, section_white_list)) {
767 warn("%s (%s): unexpected non-allocatable section.\n"
768 "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
769 "Note that for example <linux/init.h> contains\n"
770 "section definitions for use in .S files.\n\n",
771 modname, sec);
772 }
773}
774
775
776
777#define ALL_INIT_DATA_SECTIONS \
778 ".init.setup$", ".init.rodata$", \
779 ".devinit.rodata$", ".cpuinit.rodata$", ".meminit.rodata$" \
780 ".init.data$", ".devinit.data$", ".cpuinit.data$", ".meminit.data$"
781#define ALL_EXIT_DATA_SECTIONS \
782 ".exit.data$", ".devexit.data$", ".cpuexit.data$", ".memexit.data$"
783
784#define ALL_INIT_TEXT_SECTIONS \
785 ".init.text$", ".devinit.text$", ".cpuinit.text$", ".meminit.text$"
786#define ALL_EXIT_TEXT_SECTIONS \
787 ".exit.text$", ".devexit.text$", ".cpuexit.text$", ".memexit.text$"
788
789#define ALL_XXXINIT_SECTIONS DEV_INIT_SECTIONS, CPU_INIT_SECTIONS, \
790 MEM_INIT_SECTIONS
791#define ALL_XXXEXIT_SECTIONS DEV_EXIT_SECTIONS, CPU_EXIT_SECTIONS, \
792 MEM_EXIT_SECTIONS
793
794#define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
795#define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
796
797#define DATA_SECTIONS ".data$", ".data.rel$"
798#define TEXT_SECTIONS ".text$"
799
800#define INIT_SECTIONS ".init.*"
801#define DEV_INIT_SECTIONS ".devinit.*"
802#define CPU_INIT_SECTIONS ".cpuinit.*"
803#define MEM_INIT_SECTIONS ".meminit.*"
804
805#define EXIT_SECTIONS ".exit.*"
806#define DEV_EXIT_SECTIONS ".devexit.*"
807#define CPU_EXIT_SECTIONS ".cpuexit.*"
808#define MEM_EXIT_SECTIONS ".memexit.*"
809
810/* init data sections */
811static const char *init_data_sections[] = { ALL_INIT_DATA_SECTIONS, NULL };
812
813/* all init sections */
814static const char *init_sections[] = { ALL_INIT_SECTIONS, NULL };
815
816/* All init and exit sections (code + data) */
817static const char *init_exit_sections[] =
818 {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
819
820/* data section */
821static const char *data_sections[] = { DATA_SECTIONS, NULL };
822
823
824/* symbols in .data that may refer to init/exit sections */
825#define DEFAULT_SYMBOL_WHITE_LIST \
826 "*driver", \
827 "*_template", /* scsi uses *_template a lot */ \
828 "*_timer", /* arm uses ops structures named _timer a lot */ \
829 "*_sht", /* scsi also used *_sht to some extent */ \
830 "*_ops", \
831 "*_probe", \
832 "*_probe_one", \
833 "*_console"
834
835static const char *head_sections[] = { ".head.text*", NULL };
836static const char *linker_symbols[] =
837 { "__init_begin", "_sinittext", "_einittext", NULL };
838
839enum mismatch {
840 TEXT_TO_ANY_INIT,
841 DATA_TO_ANY_INIT,
842 TEXT_TO_ANY_EXIT,
843 DATA_TO_ANY_EXIT,
844 XXXINIT_TO_SOME_INIT,
845 XXXEXIT_TO_SOME_EXIT,
846 ANY_INIT_TO_ANY_EXIT,
847 ANY_EXIT_TO_ANY_INIT,
848 EXPORT_TO_INIT_EXIT,
849};
850
851struct sectioncheck {
852 const char *fromsec[20];
853 const char *tosec[20];
854 enum mismatch mismatch;
855 const char *symbol_white_list[20];
856};
857
858const struct sectioncheck sectioncheck[] = {
859/* Do not reference init/exit code/data from
860 * normal code and data
861 */
862{
863 .fromsec = { TEXT_SECTIONS, NULL },
864 .tosec = { ALL_INIT_SECTIONS, NULL },
865 .mismatch = TEXT_TO_ANY_INIT,
866 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
867},
868{
869 .fromsec = { DATA_SECTIONS, NULL },
870 .tosec = { ALL_XXXINIT_SECTIONS, NULL },
871 .mismatch = DATA_TO_ANY_INIT,
872 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
873},
874{
875 .fromsec = { DATA_SECTIONS, NULL },
876 .tosec = { INIT_SECTIONS, NULL },
877 .mismatch = DATA_TO_ANY_INIT,
878 .symbol_white_list = {
879 "*_template", "*_timer", "*_sht", "*_ops",
880 "*_probe", "*_probe_one", "*_console", NULL
881 },
882},
883{
884 .fromsec = { TEXT_SECTIONS, NULL },
885 .tosec = { ALL_EXIT_SECTIONS, NULL },
886 .mismatch = TEXT_TO_ANY_EXIT,
887 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
888},
889{
890 .fromsec = { DATA_SECTIONS, NULL },
891 .tosec = { ALL_EXIT_SECTIONS, NULL },
892 .mismatch = DATA_TO_ANY_EXIT,
893 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
894},
895/* Do not reference init code/data from devinit/cpuinit/meminit code/data */
896{
897 .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
898 .tosec = { INIT_SECTIONS, NULL },
899 .mismatch = XXXINIT_TO_SOME_INIT,
900 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
901},
902/* Do not reference cpuinit code/data from meminit code/data */
903{
904 .fromsec = { MEM_INIT_SECTIONS, NULL },
905 .tosec = { CPU_INIT_SECTIONS, NULL },
906 .mismatch = XXXINIT_TO_SOME_INIT,
907 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
908},
909/* Do not reference meminit code/data from cpuinit code/data */
910{
911 .fromsec = { CPU_INIT_SECTIONS, NULL },
912 .tosec = { MEM_INIT_SECTIONS, NULL },
913 .mismatch = XXXINIT_TO_SOME_INIT,
914 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
915},
916/* Do not reference exit code/data from devexit/cpuexit/memexit code/data */
917{
918 .fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
919 .tosec = { EXIT_SECTIONS, NULL },
920 .mismatch = XXXEXIT_TO_SOME_EXIT,
921 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
922},
923/* Do not reference cpuexit code/data from memexit code/data */
924{
925 .fromsec = { MEM_EXIT_SECTIONS, NULL },
926 .tosec = { CPU_EXIT_SECTIONS, NULL },
927 .mismatch = XXXEXIT_TO_SOME_EXIT,
928 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
929},
930/* Do not reference memexit code/data from cpuexit code/data */
931{
932 .fromsec = { CPU_EXIT_SECTIONS, NULL },
933 .tosec = { MEM_EXIT_SECTIONS, NULL },
934 .mismatch = XXXEXIT_TO_SOME_EXIT,
935 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
936},
937/* Do not use exit code/data from init code */
938{
939 .fromsec = { ALL_INIT_SECTIONS, NULL },
940 .tosec = { ALL_EXIT_SECTIONS, NULL },
941 .mismatch = ANY_INIT_TO_ANY_EXIT,
942 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
943},
944/* Do not use init code/data from exit code */
945{
946 .fromsec = { ALL_EXIT_SECTIONS, NULL },
947 .tosec = { ALL_INIT_SECTIONS, NULL },
948 .mismatch = ANY_EXIT_TO_ANY_INIT,
949 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
950},
951/* Do not export init/exit functions or data */
952{
953 .fromsec = { "__ksymtab*", NULL },
954 .tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
955 .mismatch = EXPORT_TO_INIT_EXIT,
956 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
957}
958};
959
960static const struct sectioncheck *section_mismatch(
961 const char *fromsec, const char *tosec)
962{
963 int i;
964 int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
965 const struct sectioncheck *check = &sectioncheck[0];
966
967 for (i = 0; i < elems; i++) {
968 if (match(fromsec, check->fromsec) &&
969 match(tosec, check->tosec))
970 return check;
971 check++;
972 }
973 return NULL;
974}
975
976/**
977 * Whitelist to allow certain references to pass with no warning.
978 *
979 * Pattern 1:
980 * If a module parameter is declared __initdata and permissions=0
981 * then this is legal despite the warning generated.
982 * We cannot see value of permissions here, so just ignore
983 * this pattern.
984 * The pattern is identified by:
985 * tosec = .init.data
986 * fromsec = .data*
987 * atsym =__param*
988 *
989 * Pattern 2:
990 * Many drivers utilise a *driver container with references to
991 * add, remove, probe functions etc.
992 * These functions may often be marked __devinit and we do not want to
993 * warn here.
994 * the pattern is identified by:
995 * tosec = init or exit section
996 * fromsec = data section
997 * atsym = *driver, *_template, *_sht, *_ops, *_probe,
998 * *probe_one, *_console, *_timer
999 *
1000 * Pattern 3:
1001 * Whitelist all references from .head.text to any init section
1002 *
1003 * Pattern 4:
1004 * Some symbols belong to init section but still it is ok to reference
1005 * these from non-init sections as these symbols don't have any memory
1006 * allocated for them and symbol address and value are same. So even
1007 * if init section is freed, its ok to reference those symbols.
1008 * For ex. symbols marking the init section boundaries.
1009 * This pattern is identified by
1010 * refsymname = __init_begin, _sinittext, _einittext
1011 *
1012 **/
1013static int secref_whitelist(const struct sectioncheck *mismatch,
1014 const char *fromsec, const char *fromsym,
1015 const char *tosec, const char *tosym)
1016{
1017 /* Check for pattern 1 */
1018 if (match(tosec, init_data_sections) &&
1019 match(fromsec, data_sections) &&
1020 (strncmp(fromsym, "__param", strlen("__param")) == 0))
1021 return 0;
1022
1023 /* Check for pattern 2 */
1024 if (match(tosec, init_exit_sections) &&
1025 match(fromsec, data_sections) &&
1026 match(fromsym, mismatch->symbol_white_list))
1027 return 0;
1028
1029 /* Check for pattern 3 */
1030 if (match(fromsec, head_sections) &&
1031 match(tosec, init_sections))
1032 return 0;
1033
1034 /* Check for pattern 4 */
1035 if (match(tosym, linker_symbols))
1036 return 0;
1037
1038 return 1;
1039}
1040
1041/**
1042 * Find symbol based on relocation record info.
1043 * In some cases the symbol supplied is a valid symbol so
1044 * return refsym. If st_name != 0 we assume this is a valid symbol.
1045 * In other cases the symbol needs to be looked up in the symbol table
1046 * based on section and address.
1047 * **/
1048static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
1049 Elf_Sym *relsym)
1050{
1051 Elf_Sym *sym;
1052 Elf_Sym *near = NULL;
1053 Elf64_Sword distance = 20;
1054 Elf64_Sword d;
1055
1056 if (relsym->st_name != 0)
1057 return relsym;
1058 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1059 if (sym->st_shndx != relsym->st_shndx)
1060 continue;
1061 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
1062 continue;
1063 if (sym->st_value == addr)
1064 return sym;
1065 /* Find a symbol nearby - addr are maybe negative */
1066 d = sym->st_value - addr;
1067 if (d < 0)
1068 d = addr - sym->st_value;
1069 if (d < distance) {
1070 distance = d;
1071 near = sym;
1072 }
1073 }
1074 /* We need a close match */
1075 if (distance < 20)
1076 return near;
1077 else
1078 return NULL;
1079}
1080
1081static inline int is_arm_mapping_symbol(const char *str)
1082{
1083 return str[0] == '$' && strchr("atd", str[1])
1084 && (str[2] == '\0' || str[2] == '.');
1085}
1086
1087/*
1088 * If there's no name there, ignore it; likewise, ignore it if it's
1089 * one of the magic symbols emitted used by current ARM tools.
1090 *
1091 * Otherwise if find_symbols_between() returns those symbols, they'll
1092 * fail the whitelist tests and cause lots of false alarms ... fixable
1093 * only by merging __exit and __init sections into __text, bloating
1094 * the kernel (which is especially evil on embedded platforms).
1095 */
1096static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1097{
1098 const char *name = elf->strtab + sym->st_name;
1099
1100 if (!name || !strlen(name))
1101 return 0;
1102 return !is_arm_mapping_symbol(name);
1103}
1104
1105/*
1106 * Find symbols before or equal addr and after addr - in the section sec.
1107 * If we find two symbols with equal offset prefer one with a valid name.
1108 * The ELF format may have a better way to detect what type of symbol
1109 * it is, but this works for now.
1110 **/
1111static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1112 const char *sec)
1113{
1114 Elf_Sym *sym;
1115 Elf_Sym *near = NULL;
1116 Elf_Addr distance = ~0;
1117
1118 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1119 const char *symsec;
1120
1121 if (sym->st_shndx >= SHN_LORESERVE)
1122 continue;
1123 symsec = sec_name(elf, sym->st_shndx);
1124 if (strcmp(symsec, sec) != 0)
1125 continue;
1126 if (!is_valid_name(elf, sym))
1127 continue;
1128 if (sym->st_value <= addr) {
1129 if ((addr - sym->st_value) < distance) {
1130 distance = addr - sym->st_value;
1131 near = sym;
1132 } else if ((addr - sym->st_value) == distance) {
1133 near = sym;
1134 }
1135 }
1136 }
1137 return near;
1138}
1139
1140/*
1141 * Convert a section name to the function/data attribute
1142 * .init.text => __init
1143 * .cpuinit.data => __cpudata
1144 * .memexitconst => __memconst
1145 * etc.
1146*/
1147static char *sec2annotation(const char *s)
1148{
1149 if (match(s, init_exit_sections)) {
1150 char *p = malloc(20);
1151 char *r = p;
1152
1153 *p++ = '_';
1154 *p++ = '_';
1155 if (*s == '.')
1156 s++;
1157 while (*s && *s != '.')
1158 *p++ = *s++;
1159 *p = '\0';
1160 if (*s == '.')
1161 s++;
1162 if (strstr(s, "rodata") != NULL)
1163 strcat(p, "const ");
1164 else if (strstr(s, "data") != NULL)
1165 strcat(p, "data ");
1166 else
1167 strcat(p, " ");
1168 return r; /* we leak her but we do not care */
1169 } else {
1170 return "";
1171 }
1172}
1173
1174static int is_function(Elf_Sym *sym)
1175{
1176 if (sym)
1177 return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1178 else
1179 return -1;
1180}
1181
1182/*
1183 * Print a warning about a section mismatch.
1184 * Try to find symbols near it so user can find it.
1185 * Check whitelist before warning - it may be a false positive.
1186 */
1187static void report_sec_mismatch(const char *modname,
1188 const struct sectioncheck *mismatch,
1189 const char *fromsec,
1190 unsigned long long fromaddr,
1191 const char *fromsym,
1192 int from_is_func,
1193 const char *tosec, const char *tosym,
1194 int to_is_func)
1195{
1196 const char *from, *from_p;
1197 const char *to, *to_p;
1198
1199 switch (from_is_func) {
1200 case 0: from = "variable"; from_p = ""; break;
1201 case 1: from = "function"; from_p = "()"; break;
1202 default: from = "(unknown reference)"; from_p = ""; break;
1203 }
1204 switch (to_is_func) {
1205 case 0: to = "variable"; to_p = ""; break;
1206 case 1: to = "function"; to_p = "()"; break;
1207 default: to = "(unknown reference)"; to_p = ""; break;
1208 }
1209
1210 sec_mismatch_count++;
1211 if (!sec_mismatch_verbose)
1212 return;
1213
1214 warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1215 "to the %s %s:%s%s\n",
1216 modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1217 tosym, to_p);
1218
1219 switch (mismatch->mismatch) {
1220 case TEXT_TO_ANY_INIT:
1221 fprintf(stderr,
1222 "The function %s%s() references\n"
1223 "the %s %s%s%s.\n"
1224 "This is often because %s lacks a %s\n"
1225 "annotation or the annotation of %s is wrong.\n",
1226 sec2annotation(fromsec), fromsym,
1227 to, sec2annotation(tosec), tosym, to_p,
1228 fromsym, sec2annotation(tosec), tosym);
1229 break;
1230 case DATA_TO_ANY_INIT: {
1231 const char *const *s = mismatch->symbol_white_list;
1232 fprintf(stderr,
1233 "The variable %s references\n"
1234 "the %s %s%s%s\n"
1235 "If the reference is valid then annotate the\n"
1236 "variable with __init* or __refdata (see linux/init.h) "
1237 "or name the variable:\n",
1238 fromsym, to, sec2annotation(tosec), tosym, to_p);
1239 while (*s)
1240 fprintf(stderr, "%s, ", *s++);
1241 fprintf(stderr, "\n");
1242 break;
1243 }
1244 case TEXT_TO_ANY_EXIT:
1245 fprintf(stderr,
1246 "The function %s() references a %s in an exit section.\n"
1247 "Often the %s %s%s has valid usage outside the exit section\n"
1248 "and the fix is to remove the %sannotation of %s.\n",
1249 fromsym, to, to, tosym, to_p, sec2annotation(tosec), tosym);
1250 break;
1251 case DATA_TO_ANY_EXIT: {
1252 const char *const *s = mismatch->symbol_white_list;
1253 fprintf(stderr,
1254 "The variable %s references\n"
1255 "the %s %s%s%s\n"
1256 "If the reference is valid then annotate the\n"
1257 "variable with __exit* (see linux/init.h) or "
1258 "name the variable:\n",
1259 fromsym, to, sec2annotation(tosec), tosym, to_p);
1260 while (*s)
1261 fprintf(stderr, "%s, ", *s++);
1262 fprintf(stderr, "\n");
1263 break;
1264 }
1265 case XXXINIT_TO_SOME_INIT:
1266 case XXXEXIT_TO_SOME_EXIT:
1267 fprintf(stderr,
1268 "The %s %s%s%s references\n"
1269 "a %s %s%s%s.\n"
1270 "If %s is only used by %s then\n"
1271 "annotate %s with a matching annotation.\n",
1272 from, sec2annotation(fromsec), fromsym, from_p,
1273 to, sec2annotation(tosec), tosym, to_p,
1274 tosym, fromsym, tosym);
1275 break;
1276 case ANY_INIT_TO_ANY_EXIT:
1277 fprintf(stderr,
1278 "The %s %s%s%s references\n"
1279 "a %s %s%s%s.\n"
1280 "This is often seen when error handling "
1281 "in the init function\n"
1282 "uses functionality in the exit path.\n"
1283 "The fix is often to remove the %sannotation of\n"
1284 "%s%s so it may be used outside an exit section.\n",
1285 from, sec2annotation(fromsec), fromsym, from_p,
1286 to, sec2annotation(tosec), tosym, to_p,
1287 sec2annotation(tosec), tosym, to_p);
1288 break;
1289 case ANY_EXIT_TO_ANY_INIT:
1290 fprintf(stderr,
1291 "The %s %s%s%s references\n"
1292 "a %s %s%s%s.\n"
1293 "This is often seen when error handling "
1294 "in the exit function\n"
1295 "uses functionality in the init path.\n"
1296 "The fix is often to remove the %sannotation of\n"
1297 "%s%s so it may be used outside an init section.\n",
1298 from, sec2annotation(fromsec), fromsym, from_p,
1299 to, sec2annotation(tosec), tosym, to_p,
1300 sec2annotation(tosec), tosym, to_p);
1301 break;
1302 case EXPORT_TO_INIT_EXIT:
1303 fprintf(stderr,
1304 "The symbol %s is exported and annotated %s\n"
1305 "Fix this by removing the %sannotation of %s "
1306 "or drop the export.\n",
1307 tosym, sec2annotation(tosec), sec2annotation(tosec), tosym);
1308 break;
1309 }
1310 fprintf(stderr, "\n");
1311}
1312
1313static void check_section_mismatch(const char *modname, struct elf_info *elf,
1314 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1315{
1316 const char *tosec;
1317 const struct sectioncheck *mismatch;
1318
1319 tosec = sec_name(elf, sym->st_shndx);
1320 mismatch = section_mismatch(fromsec, tosec);
1321 if (mismatch) {
1322 Elf_Sym *to;
1323 Elf_Sym *from;
1324 const char *tosym;
1325 const char *fromsym;
1326
1327 from = find_elf_symbol2(elf, r->r_offset, fromsec);
1328 fromsym = sym_name(elf, from);
1329 to = find_elf_symbol(elf, r->r_addend, sym);
1330 tosym = sym_name(elf, to);
1331
1332 /* check whitelist - we may ignore it */
1333 if (secref_whitelist(mismatch,
1334 fromsec, fromsym, tosec, tosym)) {
1335 report_sec_mismatch(modname, mismatch,
1336 fromsec, r->r_offset, fromsym,
1337 is_function(from), tosec, tosym,
1338 is_function(to));
1339 }
1340 }
1341}
1342
1343static unsigned int *reloc_location(struct elf_info *elf,
1344 Elf_Shdr *sechdr, Elf_Rela *r)
1345{
1346 Elf_Shdr *sechdrs = elf->sechdrs;
1347 int section = sechdr->sh_info;
1348
1349 return (void *)elf->hdr + sechdrs[section].sh_offset +
1350 r->r_offset - sechdrs[section].sh_addr;
1351}
1352
1353static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1354{
1355 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1356 unsigned int *location = reloc_location(elf, sechdr, r);
1357
1358 switch (r_typ) {
1359 case R_386_32:
1360 r->r_addend = TO_NATIVE(*location);
1361 break;
1362 case R_386_PC32:
1363 r->r_addend = TO_NATIVE(*location) + 4;
1364 /* For CONFIG_RELOCATABLE=y */
1365 if (elf->hdr->e_type == ET_EXEC)
1366 r->r_addend += r->r_offset;
1367 break;
1368 }
1369 return 0;
1370}
1371
1372static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1373{
1374 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1375
1376 switch (r_typ) {
1377 case R_ARM_ABS32:
1378 /* From ARM ABI: (S + A) | T */
1379 r->r_addend = (int)(long)
1380 (elf->symtab_start + ELF_R_SYM(r->r_info));
1381 break;
1382 case R_ARM_PC24:
1383 /* From ARM ABI: ((S + A) | T) - P */
1384 r->r_addend = (int)(long)(elf->hdr +
1385 sechdr->sh_offset +
1386 (r->r_offset - sechdr->sh_addr));
1387 break;
1388 default:
1389 return 1;
1390 }
1391 return 0;
1392}
1393
1394static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1395{
1396 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1397 unsigned int *location = reloc_location(elf, sechdr, r);
1398 unsigned int inst;
1399
1400 if (r_typ == R_MIPS_HI16)
1401 return 1; /* skip this */
1402 inst = TO_NATIVE(*location);
1403 switch (r_typ) {
1404 case R_MIPS_LO16:
1405 r->r_addend = inst & 0xffff;
1406 break;
1407 case R_MIPS_26:
1408 r->r_addend = (inst & 0x03ffffff) << 2;
1409 break;
1410 case R_MIPS_32:
1411 r->r_addend = inst;
1412 break;
1413 }
1414 return 0;
1415}
1416
1417static void section_rela(const char *modname, struct elf_info *elf,
1418 Elf_Shdr *sechdr)
1419{
1420 Elf_Sym *sym;
1421 Elf_Rela *rela;
1422 Elf_Rela r;
1423 unsigned int r_sym;
1424 const char *fromsec;
1425
1426 Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1427 Elf_Rela *stop = (void *)start + sechdr->sh_size;
1428
1429 fromsec = sech_name(elf, sechdr);
1430 fromsec += strlen(".rela");
1431 /* if from section (name) is know good then skip it */
1432 if (match(fromsec, section_white_list))
1433 return;
1434
1435 for (rela = start; rela < stop; rela++) {
1436 r.r_offset = TO_NATIVE(rela->r_offset);
1437#if KERNEL_ELFCLASS == ELFCLASS64
1438 if (elf->hdr->e_machine == EM_MIPS) {
1439 unsigned int r_typ;
1440 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1441 r_sym = TO_NATIVE(r_sym);
1442 r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1443 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1444 } else {
1445 r.r_info = TO_NATIVE(rela->r_info);
1446 r_sym = ELF_R_SYM(r.r_info);
1447 }
1448#else
1449 r.r_info = TO_NATIVE(rela->r_info);
1450 r_sym = ELF_R_SYM(r.r_info);
1451#endif
1452 r.r_addend = TO_NATIVE(rela->r_addend);
1453 sym = elf->symtab_start + r_sym;
1454 /* Skip special sections */
1455 if (sym->st_shndx >= SHN_LORESERVE)
1456 continue;
1457 check_section_mismatch(modname, elf, &r, sym, fromsec);
1458 }
1459}
1460
1461static void section_rel(const char *modname, struct elf_info *elf,
1462 Elf_Shdr *sechdr)
1463{
1464 Elf_Sym *sym;
1465 Elf_Rel *rel;
1466 Elf_Rela r;
1467 unsigned int r_sym;
1468 const char *fromsec;
1469
1470 Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1471 Elf_Rel *stop = (void *)start + sechdr->sh_size;
1472
1473 fromsec = sech_name(elf, sechdr);
1474 fromsec += strlen(".rel");
1475 /* if from section (name) is know good then skip it */
1476 if (match(fromsec, section_white_list))
1477 return;
1478
1479 for (rel = start; rel < stop; rel++) {
1480 r.r_offset = TO_NATIVE(rel->r_offset);
1481#if KERNEL_ELFCLASS == ELFCLASS64
1482 if (elf->hdr->e_machine == EM_MIPS) {
1483 unsigned int r_typ;
1484 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1485 r_sym = TO_NATIVE(r_sym);
1486 r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1487 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1488 } else {
1489 r.r_info = TO_NATIVE(rel->r_info);
1490 r_sym = ELF_R_SYM(r.r_info);
1491 }
1492#else
1493 r.r_info = TO_NATIVE(rel->r_info);
1494 r_sym = ELF_R_SYM(r.r_info);
1495#endif
1496 r.r_addend = 0;
1497 switch (elf->hdr->e_machine) {
1498 case EM_386:
1499 if (addend_386_rel(elf, sechdr, &r))
1500 continue;
1501 break;
1502 case EM_ARM:
1503 if (addend_arm_rel(elf, sechdr, &r))
1504 continue;
1505 break;
1506 case EM_MIPS:
1507 if (addend_mips_rel(elf, sechdr, &r))
1508 continue;
1509 break;
1510 }
1511 sym = elf->symtab_start + r_sym;
1512 /* Skip special sections */
1513 if (sym->st_shndx >= SHN_LORESERVE)
1514 continue;
1515 check_section_mismatch(modname, elf, &r, sym, fromsec);
1516 }
1517}
1518
1519/**
1520 * A module includes a number of sections that are discarded
1521 * either when loaded or when used as built-in.
1522 * For loaded modules all functions marked __init and all data
1523 * marked __initdata will be discarded when the module has been intialized.
1524 * Likewise for modules used built-in the sections marked __exit
1525 * are discarded because __exit marked function are supposed to be called
1526 * only when a module is unloaded which never happens for built-in modules.
1527 * The check_sec_ref() function traverses all relocation records
1528 * to find all references to a section that reference a section that will
1529 * be discarded and warns about it.
1530 **/
1531static void check_sec_ref(struct module *mod, const char *modname,
1532 struct elf_info *elf)
1533{
1534 int i;
1535 Elf_Shdr *sechdrs = elf->sechdrs;
1536
1537 /* Walk through all sections */
1538 for (i = 0; i < elf->hdr->e_shnum; i++) {
1539 check_section(modname, elf, &elf->sechdrs[i]);
1540 /* We want to process only relocation sections and not .init */
1541 if (sechdrs[i].sh_type == SHT_RELA)
1542 section_rela(modname, elf, &elf->sechdrs[i]);
1543 else if (sechdrs[i].sh_type == SHT_REL)
1544 section_rel(modname, elf, &elf->sechdrs[i]);
1545 }
1546}
1547
1548static void read_symbols(char *modname)
1549{
1550 const char *symname;
1551 char *version;
1552 char *license;
1553 struct module *mod;
1554 struct elf_info info = { };
1555 Elf_Sym *sym;
1556
1557 if (!parse_elf(&info, modname))
1558 return;
1559
1560 mod = new_module(modname);
1561
1562 /* When there's no vmlinux, don't print warnings about
1563 * unresolved symbols (since there'll be too many ;) */
1564 if (is_vmlinux(modname)) {
1565 have_vmlinux = 1;
1566 mod->skip = 1;
1567 }
1568
1569 license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1570 if (info.modinfo && !license && !is_vmlinux(modname))
1571 warn("modpost: missing MODULE_LICENSE() in %s\n"
1572 "see include/linux/module.h for "
1573 "more information\n", modname);
1574 while (license) {
1575 if (license_is_gpl_compatible(license))
1576 mod->gpl_compatible = 1;
1577 else {
1578 mod->gpl_compatible = 0;
1579 break;
1580 }
1581 license = get_next_modinfo(info.modinfo, info.modinfo_len,
1582 "license", license);
1583 }
1584
1585 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1586 symname = info.strtab + sym->st_name;
1587
1588 handle_modversions(mod, &info, sym, symname);
1589 handle_moddevtable(mod, &info, sym, symname);
1590 }
1591 if (!is_vmlinux(modname) ||
1592 (is_vmlinux(modname) && vmlinux_section_warnings))
1593 check_sec_ref(mod, modname, &info);
1594
1595 version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1596 if (version)
1597 maybe_frob_rcs_version(modname, version, info.modinfo,
1598 version - (char *)info.hdr);
1599 if (version || (all_versions && !is_vmlinux(modname)))
1600 get_src_version(modname, mod->srcversion,
1601 sizeof(mod->srcversion)-1);
1602
1603 parse_elf_finish(&info);
1604
1605 /* Our trick to get versioning for module struct etc. - it's
1606 * never passed as an argument to an exported function, so
1607 * the automatic versioning doesn't pick it up, but it's really
1608 * important anyhow */
1609 if (modversions)
1610 mod->unres = alloc_symbol("module_layout", 0, mod->unres);
1611}
1612
1613#define SZ 500
1614
1615/* We first write the generated file into memory using the
1616 * following helper, then compare to the file on disk and
1617 * only update the later if anything changed */
1618
1619void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
1620 const char *fmt, ...)
1621{
1622 char tmp[SZ];
1623 int len;
1624 va_list ap;
1625
1626 va_start(ap, fmt);
1627 len = vsnprintf(tmp, SZ, fmt, ap);
1628 buf_write(buf, tmp, len);
1629 va_end(ap);
1630}
1631
1632void buf_write(struct buffer *buf, const char *s, int len)
1633{
1634 if (buf->size - buf->pos < len) {
1635 buf->size += len + SZ;
1636 buf->p = realloc(buf->p, buf->size);
1637 }
1638 strncpy(buf->p + buf->pos, s, len);
1639 buf->pos += len;
1640}
1641
1642static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
1643{
1644 const char *e = is_vmlinux(m) ?"":".ko";
1645
1646 switch (exp) {
1647 case export_gpl:
1648 fatal("modpost: GPL-incompatible module %s%s "
1649 "uses GPL-only symbol '%s'\n", m, e, s);
1650 break;
1651 case export_unused_gpl:
1652 fatal("modpost: GPL-incompatible module %s%s "
1653 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
1654 break;
1655 case export_gpl_future:
1656 warn("modpost: GPL-incompatible module %s%s "
1657 "uses future GPL-only symbol '%s'\n", m, e, s);
1658 break;
1659 case export_plain:
1660 case export_unused:
1661 case export_unknown:
1662 /* ignore */
1663 break;
1664 }
1665}
1666
1667static void check_for_unused(enum export exp, const char *m, const char *s)
1668{
1669 const char *e = is_vmlinux(m) ?"":".ko";
1670
1671 switch (exp) {
1672 case export_unused:
1673 case export_unused_gpl:
1674 warn("modpost: module %s%s "
1675 "uses symbol '%s' marked UNUSED\n", m, e, s);
1676 break;
1677 default:
1678 /* ignore */
1679 break;
1680 }
1681}
1682
1683static void check_exports(struct module *mod)
1684{
1685 struct symbol *s, *exp;
1686
1687 for (s = mod->unres; s; s = s->next) {
1688 const char *basename;
1689 exp = find_symbol(s->name);
1690 if (!exp || exp->module == mod)
1691 continue;
1692 basename = strrchr(mod->name, '/');
1693 if (basename)
1694 basename++;
1695 else
1696 basename = mod->name;
1697 if (!mod->gpl_compatible)
1698 check_for_gpl_usage(exp->export, basename, exp->name);
1699 check_for_unused(exp->export, basename, exp->name);
1700 }
1701}
1702
1703/**
1704 * Header for the generated file
1705 **/
1706static void add_header(struct buffer *b, struct module *mod)
1707{
1708 buf_printf(b, "#include <linux/module.h>\n");
1709 buf_printf(b, "#include <linux/vermagic.h>\n");
1710 buf_printf(b, "#include <linux/compiler.h>\n");
1711 buf_printf(b, "\n");
1712 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
1713 buf_printf(b, "\n");
1714 buf_printf(b, "struct module __this_module\n");
1715 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
1716 buf_printf(b, " .name = KBUILD_MODNAME,\n");
1717 if (mod->has_init)
1718 buf_printf(b, " .init = init_module,\n");
1719 if (mod->has_cleanup)
1720 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
1721 " .exit = cleanup_module,\n"
1722 "#endif\n");
1723 buf_printf(b, " .arch = MODULE_ARCH_INIT,\n");
1724 buf_printf(b, "};\n");
1725}
1726
1727static void add_staging_flag(struct buffer *b, const char *name)
1728{
1729 static const char *staging_dir = "drivers/staging";
1730
1731 if (strncmp(staging_dir, name, strlen(staging_dir)) == 0)
1732 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
1733}
1734
1735/**
1736 * Record CRCs for unresolved symbols
1737 **/
1738static int add_versions(struct buffer *b, struct module *mod)
1739{
1740 struct symbol *s, *exp;
1741 int err = 0;
1742
1743 for (s = mod->unres; s; s = s->next) {
1744 exp = find_symbol(s->name);
1745 if (!exp || exp->module == mod) {
1746 if (have_vmlinux && !s->weak) {
1747 if (warn_unresolved) {
1748 warn("\"%s\" [%s.ko] undefined!\n",
1749 s->name, mod->name);
1750 } else {
1751 merror("\"%s\" [%s.ko] undefined!\n",
1752 s->name, mod->name);
1753 err = 1;
1754 }
1755 }
1756 continue;
1757 }
1758 s->module = exp->module;
1759 s->crc_valid = exp->crc_valid;
1760 s->crc = exp->crc;
1761 }
1762
1763 if (!modversions)
1764 return err;
1765
1766 buf_printf(b, "\n");
1767 buf_printf(b, "static const struct modversion_info ____versions[]\n");
1768 buf_printf(b, "__used\n");
1769 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
1770
1771 for (s = mod->unres; s; s = s->next) {
1772 if (!s->module)
1773 continue;
1774 if (!s->crc_valid) {
1775 warn("\"%s\" [%s.ko] has no CRC!\n",
1776 s->name, mod->name);
1777 continue;
1778 }
1779 buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name);
1780 }
1781
1782 buf_printf(b, "};\n");
1783
1784 return err;
1785}
1786
1787static void add_depends(struct buffer *b, struct module *mod,
1788 struct module *modules)
1789{
1790 struct symbol *s;
1791 struct module *m;
1792 int first = 1;
1793
1794 for (m = modules; m; m = m->next)
1795 m->seen = is_vmlinux(m->name);
1796
1797 buf_printf(b, "\n");
1798 buf_printf(b, "static const char __module_depends[]\n");
1799 buf_printf(b, "__used\n");
1800 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
1801 buf_printf(b, "\"depends=");
1802 for (s = mod->unres; s; s = s->next) {
1803 const char *p;
1804 if (!s->module)
1805 continue;
1806
1807 if (s->module->seen)
1808 continue;
1809
1810 s->module->seen = 1;
1811 p = strrchr(s->module->name, '/');
1812 if (p)
1813 p++;
1814 else
1815 p = s->module->name;
1816 buf_printf(b, "%s%s", first ? "" : ",", p);
1817 first = 0;
1818 }
1819 buf_printf(b, "\";\n");
1820}
1821
1822static void add_srcversion(struct buffer *b, struct module *mod)
1823{
1824 if (mod->srcversion[0]) {
1825 buf_printf(b, "\n");
1826 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
1827 mod->srcversion);
1828 }
1829}
1830
1831static void write_if_changed(struct buffer *b, const char *fname)
1832{
1833 char *tmp;
1834 FILE *file;
1835 struct stat st;
1836
1837 file = fopen(fname, "r");
1838 if (!file)
1839 goto write;
1840
1841 if (fstat(fileno(file), &st) < 0)
1842 goto close_write;
1843
1844 if (st.st_size != b->pos)
1845 goto close_write;
1846
1847 tmp = NOFAIL(malloc(b->pos));
1848 if (fread(tmp, 1, b->pos, file) != b->pos)
1849 goto free_write;
1850
1851 if (memcmp(tmp, b->p, b->pos) != 0)
1852 goto free_write;
1853
1854 free(tmp);
1855 fclose(file);
1856 return;
1857
1858 free_write:
1859 free(tmp);
1860 close_write:
1861 fclose(file);
1862 write:
1863 file = fopen(fname, "w");
1864 if (!file) {
1865 perror(fname);
1866 exit(1);
1867 }
1868 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
1869 perror(fname);
1870 exit(1);
1871 }
1872 fclose(file);
1873}
1874
1875/* parse Module.symvers file. line format:
1876 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
1877 **/
1878static void read_dump(const char *fname, unsigned int kernel)
1879{
1880 unsigned long size, pos = 0;
1881 void *file = grab_file(fname, &size);
1882 char *line;
1883
1884 if (!file)
1885 /* No symbol versions, silently ignore */
1886 return;
1887
1888 while ((line = get_next_line(&pos, file, size))) {
1889 char *symname, *modname, *d, *export, *end;
1890 unsigned int crc;
1891 struct module *mod;
1892 struct symbol *s;
1893
1894 if (!(symname = strchr(line, '\t')))
1895 goto fail;
1896 *symname++ = '\0';
1897 if (!(modname = strchr(symname, '\t')))
1898 goto fail;
1899 *modname++ = '\0';
1900 if ((export = strchr(modname, '\t')) != NULL)
1901 *export++ = '\0';
1902 if (export && ((end = strchr(export, '\t')) != NULL))
1903 *end = '\0';
1904 crc = strtoul(line, &d, 16);
1905 if (*symname == '\0' || *modname == '\0' || *d != '\0')
1906 goto fail;
1907 mod = find_module(modname);
1908 if (!mod) {
1909 if (is_vmlinux(modname))
1910 have_vmlinux = 1;
1911 mod = new_module(modname);
1912 mod->skip = 1;
1913 }
1914 s = sym_add_exported(symname, mod, export_no(export));
1915 s->kernel = kernel;
1916 s->preloaded = 1;
1917 sym_update_crc(symname, mod, crc, export_no(export));
1918 }
1919 return;
1920fail:
1921 fatal("parse error in symbol dump file\n");
1922}
1923
1924/* For normal builds always dump all symbols.
1925 * For external modules only dump symbols
1926 * that are not read from kernel Module.symvers.
1927 **/
1928static int dump_sym(struct symbol *sym)
1929{
1930 if (!external_module)
1931 return 1;
1932 if (sym->vmlinux || sym->kernel)
1933 return 0;
1934 return 1;
1935}
1936
1937static void write_dump(const char *fname)
1938{
1939 struct buffer buf = { };
1940 struct symbol *symbol;
1941 int n;
1942
1943 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
1944 symbol = symbolhash[n];
1945 while (symbol) {
1946 if (dump_sym(symbol))
1947 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
1948 symbol->crc, symbol->name,
1949 symbol->module->name,
1950 export_str(symbol->export));
1951 symbol = symbol->next;
1952 }
1953 }
1954 write_if_changed(&buf, fname);
1955}
1956
1957struct ext_sym_list {
1958 struct ext_sym_list *next;
1959 const char *file;
1960};
1961
1962int main(int argc, char **argv)
1963{
1964 struct module *mod;
1965 struct buffer buf = { };
1966 char *kernel_read = NULL, *module_read = NULL;
1967 char *dump_write = NULL;
1968 int opt;
1969 int err;
1970 struct ext_sym_list *extsym_iter;
1971 struct ext_sym_list *extsym_start = NULL;
1972
1973 while ((opt = getopt(argc, argv, "i:I:e:cmsSo:awM:K:")) != -1) {
1974 switch (opt) {
1975 case 'i':
1976 kernel_read = optarg;
1977 break;
1978 case 'I':
1979 module_read = optarg;
1980 external_module = 1;
1981 break;
1982 case 'c':
1983 cross_build = 1;
1984 break;
1985 case 'e':
1986 external_module = 1;
1987 extsym_iter =
1988 NOFAIL(malloc(sizeof(*extsym_iter)));
1989 extsym_iter->next = extsym_start;
1990 extsym_iter->file = optarg;
1991 extsym_start = extsym_iter;
1992 break;
1993 case 'm':
1994 modversions = 1;
1995 break;
1996 case 'o':
1997 dump_write = optarg;
1998 break;
1999 case 'a':
2000 all_versions = 1;
2001 break;
2002 case 's':
2003 vmlinux_section_warnings = 0;
2004 break;
2005 case 'S':
2006 sec_mismatch_verbose = 0;
2007 break;
2008 case 'w':
2009 warn_unresolved = 1;
2010 break;
2011 default:
2012 exit(1);
2013 }
2014 }
2015
2016 if (kernel_read)
2017 read_dump(kernel_read, 1);
2018 if (module_read)
2019 read_dump(module_read, 0);
2020 while (extsym_start) {
2021 read_dump(extsym_start->file, 0);
2022 extsym_iter = extsym_start->next;
2023 free(extsym_start);
2024 extsym_start = extsym_iter;
2025 }
2026
2027 while (optind < argc)
2028 read_symbols(argv[optind++]);
2029
2030 for (mod = modules; mod; mod = mod->next) {
2031 if (mod->skip)
2032 continue;
2033 check_exports(mod);
2034 }
2035
2036 err = 0;
2037
2038 for (mod = modules; mod; mod = mod->next) {
2039 char fname[strlen(mod->name) + 10];
2040
2041 if (mod->skip)
2042 continue;
2043
2044 buf.pos = 0;
2045
2046 add_header(&buf, mod);
2047 add_staging_flag(&buf, mod->name);
2048 err |= add_versions(&buf, mod);
2049 add_depends(&buf, mod, modules);
2050 add_moddevtable(&buf, mod);
2051 add_srcversion(&buf, mod);
2052
2053 sprintf(fname, "%s.mod.c", mod->name);
2054 write_if_changed(&buf, fname);
2055 }
2056
2057 if (dump_write)
2058 write_dump(dump_write);
2059 if (sec_mismatch_count && !sec_mismatch_verbose)
2060 warn("modpost: Found %d section mismatch(es).\n"
2061 "To see full details build your kernel with:\n"
2062 "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n",
2063 sec_mismatch_count);
2064
2065 return err;
2066}