projects/linux·blob v4.10 · refs

2519 lines · 66.0 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 <string.h>
18#include <limits.h>
19#include <stdbool.h>
20#include <errno.h>
21#include "modpost.h"
22#include "../../include/generated/autoconf.h"
23#include "../../include/linux/license.h"
24#include "../../include/linux/export.h"
25
26/* Are we using CONFIG_MODVERSIONS? */
27static int modversions = 0;
28/* Warn about undefined symbols? (do so if we have vmlinux) */
29static int have_vmlinux = 0;
30/* Is CONFIG_MODULE_SRCVERSION_ALL set? */
31static int all_versions = 0;
32/* If we are modposting external module set to 1 */
33static int external_module = 0;
34/* Warn about section mismatch in vmlinux if set to 1 */
35static int vmlinux_section_warnings = 1;
36/* Only warn about unresolved symbols */
37static int warn_unresolved = 0;
38/* How a symbol is exported */
39static int sec_mismatch_count = 0;
40static int sec_mismatch_verbose = 1;
41static int sec_mismatch_fatal = 0;
42/* ignore missing files */
43static int ignore_missing_files;
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 inline bool strends(const char *str, const char *postfix)
88{
89 if (strlen(str) < strlen(postfix))
90 return false;
91
92 return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0;
93}
94
95static int is_vmlinux(const char *modname)
96{
97 const char *myname;
98
99 myname = strrchr(modname, '/');
100 if (myname)
101 myname++;
102 else
103 myname = modname;
104
105 return (strcmp(myname, "vmlinux") == 0) ||
106 (strcmp(myname, "vmlinux.o") == 0);
107}
108
109void *do_nofail(void *ptr, const char *expr)
110{
111 if (!ptr)
112 fatal("modpost: Memory allocation failure: %s.\n", expr);
113
114 return ptr;
115}
116
117/* A list of all modules we processed */
118static struct module *modules;
119
120static struct module *find_module(char *modname)
121{
122 struct module *mod;
123
124 for (mod = modules; mod; mod = mod->next)
125 if (strcmp(mod->name, modname) == 0)
126 break;
127 return mod;
128}
129
130static struct module *new_module(const char *modname)
131{
132 struct module *mod;
133 char *p;
134
135 mod = NOFAIL(malloc(sizeof(*mod)));
136 memset(mod, 0, sizeof(*mod));
137 p = NOFAIL(strdup(modname));
138
139 /* strip trailing .o */
140 if (strends(p, ".o")) {
141 p[strlen(p) - 2] = '\0';
142 mod->is_dot_o = 1;
143 }
144
145 /* add to list */
146 mod->name = p;
147 mod->gpl_compatible = -1;
148 mod->next = modules;
149 modules = mod;
150
151 return mod;
152}
153
154/* A hash of all exported symbols,
155 * struct symbol is also used for lists of unresolved symbols */
156
157#define SYMBOL_HASH_SIZE 1024
158
159struct symbol {
160 struct symbol *next;
161 struct module *module;
162 unsigned int crc;
163 int crc_valid;
164 unsigned int weak:1;
165 unsigned int vmlinux:1; /* 1 if symbol is defined in vmlinux */
166 unsigned int kernel:1; /* 1 if symbol is from kernel
167 * (only for external modules) **/
168 unsigned int preloaded:1; /* 1 if symbol from Module.symvers, or crc */
169 enum export export; /* Type of export */
170 char name[0];
171};
172
173static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
174
175/* This is based on the hash agorithm from gdbm, via tdb */
176static inline unsigned int tdb_hash(const char *name)
177{
178 unsigned value; /* Used to compute the hash value. */
179 unsigned i; /* Used to cycle through random values. */
180
181 /* Set the initial value from the key size. */
182 for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
183 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
184
185 return (1103515243 * value + 12345);
186}
187
188/**
189 * Allocate a new symbols for use in the hash of exported symbols or
190 * the list of unresolved symbols per module
191 **/
192static struct symbol *alloc_symbol(const char *name, unsigned int weak,
193 struct symbol *next)
194{
195 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
196
197 memset(s, 0, sizeof(*s));
198 strcpy(s->name, name);
199 s->weak = weak;
200 s->next = next;
201 return s;
202}
203
204/* For the hash of exported symbols */
205static struct symbol *new_symbol(const char *name, struct module *module,
206 enum export export)
207{
208 unsigned int hash;
209 struct symbol *new;
210
211 hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
212 new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
213 new->module = module;
214 new->export = export;
215 return new;
216}
217
218static struct symbol *find_symbol(const char *name)
219{
220 struct symbol *s;
221
222 /* For our purposes, .foo matches foo. PPC64 needs this. */
223 if (name[0] == '.')
224 name++;
225
226 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
227 if (strcmp(s->name, name) == 0)
228 return s;
229 }
230 return NULL;
231}
232
233static const struct {
234 const char *str;
235 enum export export;
236} export_list[] = {
237 { .str = "EXPORT_SYMBOL", .export = export_plain },
238 { .str = "EXPORT_UNUSED_SYMBOL", .export = export_unused },
239 { .str = "EXPORT_SYMBOL_GPL", .export = export_gpl },
240 { .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
241 { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
242 { .str = "(unknown)", .export = export_unknown },
243};
244
245
246static const char *export_str(enum export ex)
247{
248 return export_list[ex].str;
249}
250
251static enum export export_no(const char *s)
252{
253 int i;
254
255 if (!s)
256 return export_unknown;
257 for (i = 0; export_list[i].export != export_unknown; i++) {
258 if (strcmp(export_list[i].str, s) == 0)
259 return export_list[i].export;
260 }
261 return export_unknown;
262}
263
264static const char *sec_name(struct elf_info *elf, int secindex);
265
266#define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)
267
268static enum export export_from_secname(struct elf_info *elf, unsigned int sec)
269{
270 const char *secname = sec_name(elf, sec);
271
272 if (strstarts(secname, "___ksymtab+"))
273 return export_plain;
274 else if (strstarts(secname, "___ksymtab_unused+"))
275 return export_unused;
276 else if (strstarts(secname, "___ksymtab_gpl+"))
277 return export_gpl;
278 else if (strstarts(secname, "___ksymtab_unused_gpl+"))
279 return export_unused_gpl;
280 else if (strstarts(secname, "___ksymtab_gpl_future+"))
281 return export_gpl_future;
282 else
283 return export_unknown;
284}
285
286static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
287{
288 if (sec == elf->export_sec)
289 return export_plain;
290 else if (sec == elf->export_unused_sec)
291 return export_unused;
292 else if (sec == elf->export_gpl_sec)
293 return export_gpl;
294 else if (sec == elf->export_unused_gpl_sec)
295 return export_unused_gpl;
296 else if (sec == elf->export_gpl_future_sec)
297 return export_gpl_future;
298 else
299 return export_unknown;
300}
301
302/**
303 * Add an exported symbol - it may have already been added without a
304 * CRC, in this case just update the CRC
305 **/
306static struct symbol *sym_add_exported(const char *name, struct module *mod,
307 enum export export)
308{
309 struct symbol *s = find_symbol(name);
310
311 if (!s) {
312 s = new_symbol(name, mod, export);
313 } else {
314 if (!s->preloaded) {
315 warn("%s: '%s' exported twice. Previous export "
316 "was in %s%s\n", mod->name, name,
317 s->module->name,
318 is_vmlinux(s->module->name) ?"":".ko");
319 } else {
320 /* In case Module.symvers was out of date */
321 s->module = mod;
322 }
323 }
324 s->preloaded = 0;
325 s->vmlinux = is_vmlinux(mod->name);
326 s->kernel = 0;
327 s->export = export;
328 return s;
329}
330
331static void sym_update_crc(const char *name, struct module *mod,
332 unsigned int crc, enum export export)
333{
334 struct symbol *s = find_symbol(name);
335
336 if (!s) {
337 s = new_symbol(name, mod, export);
338 /* Don't complain when we find it later. */
339 s->preloaded = 1;
340 }
341 s->crc = crc;
342 s->crc_valid = 1;
343}
344
345void *grab_file(const char *filename, unsigned long *size)
346{
347 struct stat st;
348 void *map = MAP_FAILED;
349 int fd;
350
351 fd = open(filename, O_RDONLY);
352 if (fd < 0)
353 return NULL;
354 if (fstat(fd, &st))
355 goto failed;
356
357 *size = st.st_size;
358 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
359
360failed:
361 close(fd);
362 if (map == MAP_FAILED)
363 return NULL;
364 return map;
365}
366
367/**
368 * Return a copy of the next line in a mmap'ed file.
369 * spaces in the beginning of the line is trimmed away.
370 * Return a pointer to a static buffer.
371 **/
372char *get_next_line(unsigned long *pos, void *file, unsigned long size)
373{
374 static char line[4096];
375 int skip = 1;
376 size_t len = 0;
377 signed char *p = (signed char *)file + *pos;
378 char *s = line;
379
380 for (; *pos < size ; (*pos)++) {
381 if (skip && isspace(*p)) {
382 p++;
383 continue;
384 }
385 skip = 0;
386 if (*p != '\n' && (*pos < size)) {
387 len++;
388 *s++ = *p++;
389 if (len > 4095)
390 break; /* Too long, stop */
391 } else {
392 /* End of string */
393 *s = '\0';
394 return line;
395 }
396 }
397 /* End of buffer */
398 return NULL;
399}
400
401void release_file(void *file, unsigned long size)
402{
403 munmap(file, size);
404}
405
406static int parse_elf(struct elf_info *info, const char *filename)
407{
408 unsigned int i;
409 Elf_Ehdr *hdr;
410 Elf_Shdr *sechdrs;
411 Elf_Sym *sym;
412 const char *secstrings;
413 unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
414
415 hdr = grab_file(filename, &info->size);
416 if (!hdr) {
417 if (ignore_missing_files) {
418 fprintf(stderr, "%s: %s (ignored)\n", filename,
419 strerror(errno));
420 return 0;
421 }
422 perror(filename);
423 exit(1);
424 }
425 info->hdr = hdr;
426 if (info->size < sizeof(*hdr)) {
427 /* file too small, assume this is an empty .o file */
428 return 0;
429 }
430 /* Is this a valid ELF file? */
431 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
432 (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
433 (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
434 (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
435 /* Not an ELF file - silently ignore it */
436 return 0;
437 }
438 /* Fix endianness in ELF header */
439 hdr->e_type = TO_NATIVE(hdr->e_type);
440 hdr->e_machine = TO_NATIVE(hdr->e_machine);
441 hdr->e_version = TO_NATIVE(hdr->e_version);
442 hdr->e_entry = TO_NATIVE(hdr->e_entry);
443 hdr->e_phoff = TO_NATIVE(hdr->e_phoff);
444 hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
445 hdr->e_flags = TO_NATIVE(hdr->e_flags);
446 hdr->e_ehsize = TO_NATIVE(hdr->e_ehsize);
447 hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
448 hdr->e_phnum = TO_NATIVE(hdr->e_phnum);
449 hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
450 hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
451 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
452 sechdrs = (void *)hdr + hdr->e_shoff;
453 info->sechdrs = sechdrs;
454
455 /* Check if file offset is correct */
456 if (hdr->e_shoff > info->size) {
457 fatal("section header offset=%lu in file '%s' is bigger than "
458 "filesize=%lu\n", (unsigned long)hdr->e_shoff,
459 filename, info->size);
460 return 0;
461 }
462
463 if (hdr->e_shnum == SHN_UNDEF) {
464 /*
465 * There are more than 64k sections,
466 * read count from .sh_size.
467 */
468 info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
469 }
470 else {
471 info->num_sections = hdr->e_shnum;
472 }
473 if (hdr->e_shstrndx == SHN_XINDEX) {
474 info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
475 }
476 else {
477 info->secindex_strings = hdr->e_shstrndx;
478 }
479
480 /* Fix endianness in section headers */
481 for (i = 0; i < info->num_sections; i++) {
482 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
483 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
484 sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags);
485 sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr);
486 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
487 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
488 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
489 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info);
490 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
491 sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize);
492 }
493 /* Find symbol table. */
494 secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
495 for (i = 1; i < info->num_sections; i++) {
496 const char *secname;
497 int nobits = sechdrs[i].sh_type == SHT_NOBITS;
498
499 if (!nobits && sechdrs[i].sh_offset > info->size) {
500 fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
501 "sizeof(*hrd)=%zu\n", filename,
502 (unsigned long)sechdrs[i].sh_offset,
503 sizeof(*hdr));
504 return 0;
505 }
506 secname = secstrings + sechdrs[i].sh_name;
507 if (strcmp(secname, ".modinfo") == 0) {
508 if (nobits)
509 fatal("%s has NOBITS .modinfo\n", filename);
510 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
511 info->modinfo_len = sechdrs[i].sh_size;
512 } else if (strcmp(secname, "__ksymtab") == 0)
513 info->export_sec = i;
514 else if (strcmp(secname, "__ksymtab_unused") == 0)
515 info->export_unused_sec = i;
516 else if (strcmp(secname, "__ksymtab_gpl") == 0)
517 info->export_gpl_sec = i;
518 else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
519 info->export_unused_gpl_sec = i;
520 else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
521 info->export_gpl_future_sec = i;
522
523 if (sechdrs[i].sh_type == SHT_SYMTAB) {
524 unsigned int sh_link_idx;
525 symtab_idx = i;
526 info->symtab_start = (void *)hdr +
527 sechdrs[i].sh_offset;
528 info->symtab_stop = (void *)hdr +
529 sechdrs[i].sh_offset + sechdrs[i].sh_size;
530 sh_link_idx = sechdrs[i].sh_link;
531 info->strtab = (void *)hdr +
532 sechdrs[sh_link_idx].sh_offset;
533 }
534
535 /* 32bit section no. table? ("more than 64k sections") */
536 if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
537 symtab_shndx_idx = i;
538 info->symtab_shndx_start = (void *)hdr +
539 sechdrs[i].sh_offset;
540 info->symtab_shndx_stop = (void *)hdr +
541 sechdrs[i].sh_offset + sechdrs[i].sh_size;
542 }
543 }
544 if (!info->symtab_start)
545 fatal("%s has no symtab?\n", filename);
546
547 /* Fix endianness in symbols */
548 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
549 sym->st_shndx = TO_NATIVE(sym->st_shndx);
550 sym->st_name = TO_NATIVE(sym->st_name);
551 sym->st_value = TO_NATIVE(sym->st_value);
552 sym->st_size = TO_NATIVE(sym->st_size);
553 }
554
555 if (symtab_shndx_idx != ~0U) {
556 Elf32_Word *p;
557 if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
558 fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
559 filename, sechdrs[symtab_shndx_idx].sh_link,
560 symtab_idx);
561 /* Fix endianness */
562 for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
563 p++)
564 *p = TO_NATIVE(*p);
565 }
566
567 return 1;
568}
569
570static void parse_elf_finish(struct elf_info *info)
571{
572 release_file(info->hdr, info->size);
573}
574
575static int ignore_undef_symbol(struct elf_info *info, const char *symname)
576{
577 /* ignore __this_module, it will be resolved shortly */
578 if (strcmp(symname, VMLINUX_SYMBOL_STR(__this_module)) == 0)
579 return 1;
580 /* ignore global offset table */
581 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
582 return 1;
583 if (info->hdr->e_machine == EM_PPC)
584 /* Special register function linked on all modules during final link of .ko */
585 if (strncmp(symname, "_restgpr_", sizeof("_restgpr_") - 1) == 0 ||
586 strncmp(symname, "_savegpr_", sizeof("_savegpr_") - 1) == 0 ||
587 strncmp(symname, "_rest32gpr_", sizeof("_rest32gpr_") - 1) == 0 ||
588 strncmp(symname, "_save32gpr_", sizeof("_save32gpr_") - 1) == 0 ||
589 strncmp(symname, "_restvr_", sizeof("_restvr_") - 1) == 0 ||
590 strncmp(symname, "_savevr_", sizeof("_savevr_") - 1) == 0)
591 return 1;
592 if (info->hdr->e_machine == EM_PPC64)
593 /* Special register function linked on all modules during final link of .ko */
594 if (strncmp(symname, "_restgpr0_", sizeof("_restgpr0_") - 1) == 0 ||
595 strncmp(symname, "_savegpr0_", sizeof("_savegpr0_") - 1) == 0 ||
596 strncmp(symname, "_restvr_", sizeof("_restvr_") - 1) == 0 ||
597 strncmp(symname, "_savevr_", sizeof("_savevr_") - 1) == 0 ||
598 strcmp(symname, ".TOC.") == 0)
599 return 1;
600 /* Do not ignore this symbol */
601 return 0;
602}
603
604#define CRC_PFX VMLINUX_SYMBOL_STR(__crc_)
605#define KSYMTAB_PFX VMLINUX_SYMBOL_STR(__ksymtab_)
606
607static void handle_modversions(struct module *mod, struct elf_info *info,
608 Elf_Sym *sym, const char *symname)
609{
610 unsigned int crc;
611 enum export export;
612 bool is_crc = false;
613
614 if ((!is_vmlinux(mod->name) || mod->is_dot_o) &&
615 strncmp(symname, "__ksymtab", 9) == 0)
616 export = export_from_secname(info, get_secindex(info, sym));
617 else
618 export = export_from_sec(info, get_secindex(info, sym));
619
620 /* CRC'd symbol */
621 if (strncmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
622 is_crc = true;
623 crc = (unsigned int) sym->st_value;
624 if (sym->st_shndx != SHN_UNDEF && sym->st_shndx != SHN_ABS) {
625 unsigned int *crcp;
626
627 /* symbol points to the CRC in the ELF object */
628 crcp = (void *)info->hdr + sym->st_value +
629 info->sechdrs[sym->st_shndx].sh_offset -
630 (info->hdr->e_type != ET_REL ?
631 info->sechdrs[sym->st_shndx].sh_addr : 0);
632 crc = *crcp;
633 }
634 sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
635 export);
636 }
637
638 switch (sym->st_shndx) {
639 case SHN_COMMON:
640 if (!strncmp(symname, "__gnu_lto_", sizeof("__gnu_lto_")-1)) {
641 /* Should warn here, but modpost runs before the linker */
642 } else
643 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
644 break;
645 case SHN_UNDEF:
646 /* undefined symbol */
647 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
648 ELF_ST_BIND(sym->st_info) != STB_WEAK)
649 break;
650 if (ignore_undef_symbol(info, symname))
651 break;
652/* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
653#if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
654/* add compatibility with older glibc */
655#ifndef STT_SPARC_REGISTER
656#define STT_SPARC_REGISTER STT_REGISTER
657#endif
658 if (info->hdr->e_machine == EM_SPARC ||
659 info->hdr->e_machine == EM_SPARCV9) {
660 /* Ignore register directives. */
661 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
662 break;
663 if (symname[0] == '.') {
664 char *munged = strdup(symname);
665 munged[0] = '_';
666 munged[1] = toupper(munged[1]);
667 symname = munged;
668 }
669 }
670#endif
671
672#ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX
673 if (symname[0] != '_')
674 break;
675 else
676 symname++;
677#endif
678 if (is_crc) {
679 const char *e = is_vmlinux(mod->name) ?"":".ko";
680 warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n", symname + strlen(CRC_PFX), mod->name, e);
681 }
682 mod->unres = alloc_symbol(symname,
683 ELF_ST_BIND(sym->st_info) == STB_WEAK,
684 mod->unres);
685 break;
686 default:
687 /* All exported symbols */
688 if (strncmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
689 sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
690 export);
691 }
692 if (strcmp(symname, VMLINUX_SYMBOL_STR(init_module)) == 0)
693 mod->has_init = 1;
694 if (strcmp(symname, VMLINUX_SYMBOL_STR(cleanup_module)) == 0)
695 mod->has_cleanup = 1;
696 break;
697 }
698}
699
700/**
701 * Parse tag=value strings from .modinfo section
702 **/
703static char *next_string(char *string, unsigned long *secsize)
704{
705 /* Skip non-zero chars */
706 while (string[0]) {
707 string++;
708 if ((*secsize)-- <= 1)
709 return NULL;
710 }
711
712 /* Skip any zero padding. */
713 while (!string[0]) {
714 string++;
715 if ((*secsize)-- <= 1)
716 return NULL;
717 }
718 return string;
719}
720
721static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
722 const char *tag, char *info)
723{
724 char *p;
725 unsigned int taglen = strlen(tag);
726 unsigned long size = modinfo_len;
727
728 if (info) {
729 size -= info - (char *)modinfo;
730 modinfo = next_string(info, &size);
731 }
732
733 for (p = modinfo; p; p = next_string(p, &size)) {
734 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
735 return p + taglen + 1;
736 }
737 return NULL;
738}
739
740static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
741 const char *tag)
742
743{
744 return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
745}
746
747/**
748 * Test if string s ends in string sub
749 * return 0 if match
750 **/
751static int strrcmp(const char *s, const char *sub)
752{
753 int slen, sublen;
754
755 if (!s || !sub)
756 return 1;
757
758 slen = strlen(s);
759 sublen = strlen(sub);
760
761 if ((slen == 0) || (sublen == 0))
762 return 1;
763
764 if (sublen > slen)
765 return 1;
766
767 return memcmp(s + slen - sublen, sub, sublen);
768}
769
770static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
771{
772 if (sym)
773 return elf->strtab + sym->st_name;
774 else
775 return "(unknown)";
776}
777
778static const char *sec_name(struct elf_info *elf, int secindex)
779{
780 Elf_Shdr *sechdrs = elf->sechdrs;
781 return (void *)elf->hdr +
782 elf->sechdrs[elf->secindex_strings].sh_offset +
783 sechdrs[secindex].sh_name;
784}
785
786static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr)
787{
788 return (void *)elf->hdr +
789 elf->sechdrs[elf->secindex_strings].sh_offset +
790 sechdr->sh_name;
791}
792
793/* The pattern is an array of simple patterns.
794 * "foo" will match an exact string equal to "foo"
795 * "*foo" will match a string that ends with "foo"
796 * "foo*" will match a string that begins with "foo"
797 * "*foo*" will match a string that contains "foo"
798 */
799static int match(const char *sym, const char * const pat[])
800{
801 const char *p;
802 while (*pat) {
803 p = *pat++;
804 const char *endp = p + strlen(p) - 1;
805
806 /* "*foo*" */
807 if (*p == '*' && *endp == '*') {
808 char *here, *bare = strndup(p + 1, strlen(p) - 2);
809
810 here = strstr(sym, bare);
811 free(bare);
812 if (here != NULL)
813 return 1;
814 }
815 /* "*foo" */
816 else if (*p == '*') {
817 if (strrcmp(sym, p + 1) == 0)
818 return 1;
819 }
820 /* "foo*" */
821 else if (*endp == '*') {
822 if (strncmp(sym, p, strlen(p) - 1) == 0)
823 return 1;
824 }
825 /* no wildcards */
826 else {
827 if (strcmp(p, sym) == 0)
828 return 1;
829 }
830 }
831 /* no match */
832 return 0;
833}
834
835/* sections that we do not want to do full section mismatch check on */
836static const char *const section_white_list[] =
837{
838 ".comment*",
839 ".debug*",
840 ".cranges", /* sh64 */
841 ".zdebug*", /* Compressed debug sections. */
842 ".GCC-command-line", /* mn10300 */
843 ".GCC.command.line", /* record-gcc-switches, non mn10300 */
844 ".mdebug*", /* alpha, score, mips etc. */
845 ".pdr", /* alpha, score, mips etc. */
846 ".stab*",
847 ".note*",
848 ".got*",
849 ".toc*",
850 ".xt.prop", /* xtensa */
851 ".xt.lit", /* xtensa */
852 ".arcextmap*", /* arc */
853 ".gnu.linkonce.arcext*", /* arc : modules */
854 ".cmem*", /* EZchip */
855 ".fmt_slot*", /* EZchip */
856 ".gnu.lto*",
857 NULL
858};
859
860/*
861 * This is used to find sections missing the SHF_ALLOC flag.
862 * The cause of this is often a section specified in assembler
863 * without "ax" / "aw".
864 */
865static void check_section(const char *modname, struct elf_info *elf,
866 Elf_Shdr *sechdr)
867{
868 const char *sec = sech_name(elf, sechdr);
869
870 if (sechdr->sh_type == SHT_PROGBITS &&
871 !(sechdr->sh_flags & SHF_ALLOC) &&
872 !match(sec, section_white_list)) {
873 warn("%s (%s): unexpected non-allocatable section.\n"
874 "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
875 "Note that for example <linux/init.h> contains\n"
876 "section definitions for use in .S files.\n\n",
877 modname, sec);
878 }
879}
880
881
882
883#define ALL_INIT_DATA_SECTIONS \
884 ".init.setup", ".init.rodata", ".meminit.rodata", \
885 ".init.data", ".meminit.data"
886#define ALL_EXIT_DATA_SECTIONS \
887 ".exit.data", ".memexit.data"
888
889#define ALL_INIT_TEXT_SECTIONS \
890 ".init.text", ".meminit.text"
891#define ALL_EXIT_TEXT_SECTIONS \
892 ".exit.text", ".memexit.text"
893
894#define ALL_PCI_INIT_SECTIONS \
895 ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
896 ".pci_fixup_enable", ".pci_fixup_resume", \
897 ".pci_fixup_resume_early", ".pci_fixup_suspend"
898
899#define ALL_XXXINIT_SECTIONS MEM_INIT_SECTIONS
900#define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS
901
902#define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
903#define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
904
905#define DATA_SECTIONS ".data", ".data.rel"
906#define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \
907 ".kprobes.text", ".cpuidle.text"
908#define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
909 ".fixup", ".entry.text", ".exception.text", ".text.*", \
910 ".coldtext"
911
912#define INIT_SECTIONS ".init.*"
913#define MEM_INIT_SECTIONS ".meminit.*"
914
915#define EXIT_SECTIONS ".exit.*"
916#define MEM_EXIT_SECTIONS ".memexit.*"
917
918#define ALL_TEXT_SECTIONS ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \
919 TEXT_SECTIONS, OTHER_TEXT_SECTIONS
920
921/* init data sections */
922static const char *const init_data_sections[] =
923 { ALL_INIT_DATA_SECTIONS, NULL };
924
925/* all init sections */
926static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL };
927
928/* All init and exit sections (code + data) */
929static const char *const init_exit_sections[] =
930 {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
931
932/* all text sections */
933static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL };
934
935/* data section */
936static const char *const data_sections[] = { DATA_SECTIONS, NULL };
937
938
939/* symbols in .data that may refer to init/exit sections */
940#define DEFAULT_SYMBOL_WHITE_LIST \
941 "*driver", \
942 "*_template", /* scsi uses *_template a lot */ \
943 "*_timer", /* arm uses ops structures named _timer a lot */ \
944 "*_sht", /* scsi also used *_sht to some extent */ \
945 "*_ops", \
946 "*_probe", \
947 "*_probe_one", \
948 "*_console"
949
950static const char *const head_sections[] = { ".head.text*", NULL };
951static const char *const linker_symbols[] =
952 { "__init_begin", "_sinittext", "_einittext", NULL };
953static const char *const optim_symbols[] = { "*.constprop.*", NULL };
954
955enum mismatch {
956 TEXT_TO_ANY_INIT,
957 DATA_TO_ANY_INIT,
958 TEXT_TO_ANY_EXIT,
959 DATA_TO_ANY_EXIT,
960 XXXINIT_TO_SOME_INIT,
961 XXXEXIT_TO_SOME_EXIT,
962 ANY_INIT_TO_ANY_EXIT,
963 ANY_EXIT_TO_ANY_INIT,
964 EXPORT_TO_INIT_EXIT,
965 EXTABLE_TO_NON_TEXT,
966};
967
968/**
969 * Describe how to match sections on different criterias:
970 *
971 * @fromsec: Array of sections to be matched.
972 *
973 * @bad_tosec: Relocations applied to a section in @fromsec to a section in
974 * this array is forbidden (black-list). Can be empty.
975 *
976 * @good_tosec: Relocations applied to a section in @fromsec must be
977 * targetting sections in this array (white-list). Can be empty.
978 *
979 * @mismatch: Type of mismatch.
980 *
981 * @symbol_white_list: Do not match a relocation to a symbol in this list
982 * even if it is targetting a section in @bad_to_sec.
983 *
984 * @handler: Specific handler to call when a match is found. If NULL,
985 * default_mismatch_handler() will be called.
986 *
987 */
988struct sectioncheck {
989 const char *fromsec[20];
990 const char *bad_tosec[20];
991 const char *good_tosec[20];
992 enum mismatch mismatch;
993 const char *symbol_white_list[20];
994 void (*handler)(const char *modname, struct elf_info *elf,
995 const struct sectioncheck* const mismatch,
996 Elf_Rela *r, Elf_Sym *sym, const char *fromsec);
997
998};
999
1000static void extable_mismatch_handler(const char *modname, struct elf_info *elf,
1001 const struct sectioncheck* const mismatch,
1002 Elf_Rela *r, Elf_Sym *sym,
1003 const char *fromsec);
1004
1005static const struct sectioncheck sectioncheck[] = {
1006/* Do not reference init/exit code/data from
1007 * normal code and data
1008 */
1009{
1010 .fromsec = { TEXT_SECTIONS, NULL },
1011 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1012 .mismatch = TEXT_TO_ANY_INIT,
1013 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1014},
1015{
1016 .fromsec = { DATA_SECTIONS, NULL },
1017 .bad_tosec = { ALL_XXXINIT_SECTIONS, NULL },
1018 .mismatch = DATA_TO_ANY_INIT,
1019 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1020},
1021{
1022 .fromsec = { DATA_SECTIONS, NULL },
1023 .bad_tosec = { INIT_SECTIONS, NULL },
1024 .mismatch = DATA_TO_ANY_INIT,
1025 .symbol_white_list = {
1026 "*_template", "*_timer", "*_sht", "*_ops",
1027 "*_probe", "*_probe_one", "*_console", NULL
1028 },
1029},
1030{
1031 .fromsec = { TEXT_SECTIONS, NULL },
1032 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1033 .mismatch = TEXT_TO_ANY_EXIT,
1034 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1035},
1036{
1037 .fromsec = { DATA_SECTIONS, NULL },
1038 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1039 .mismatch = DATA_TO_ANY_EXIT,
1040 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1041},
1042/* Do not reference init code/data from meminit code/data */
1043{
1044 .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
1045 .bad_tosec = { INIT_SECTIONS, NULL },
1046 .mismatch = XXXINIT_TO_SOME_INIT,
1047 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1048},
1049/* Do not reference exit code/data from memexit code/data */
1050{
1051 .fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
1052 .bad_tosec = { EXIT_SECTIONS, NULL },
1053 .mismatch = XXXEXIT_TO_SOME_EXIT,
1054 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1055},
1056/* Do not use exit code/data from init code */
1057{
1058 .fromsec = { ALL_INIT_SECTIONS, NULL },
1059 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1060 .mismatch = ANY_INIT_TO_ANY_EXIT,
1061 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1062},
1063/* Do not use init code/data from exit code */
1064{
1065 .fromsec = { ALL_EXIT_SECTIONS, NULL },
1066 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1067 .mismatch = ANY_EXIT_TO_ANY_INIT,
1068 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1069},
1070{
1071 .fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
1072 .bad_tosec = { INIT_SECTIONS, NULL },
1073 .mismatch = ANY_INIT_TO_ANY_EXIT,
1074 .symbol_white_list = { NULL },
1075},
1076/* Do not export init/exit functions or data */
1077{
1078 .fromsec = { "__ksymtab*", NULL },
1079 .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
1080 .mismatch = EXPORT_TO_INIT_EXIT,
1081 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1082},
1083{
1084 .fromsec = { "__ex_table", NULL },
1085 /* If you're adding any new black-listed sections in here, consider
1086 * adding a special 'printer' for them in scripts/check_extable.
1087 */
1088 .bad_tosec = { ".altinstr_replacement", NULL },
1089 .good_tosec = {ALL_TEXT_SECTIONS , NULL},
1090 .mismatch = EXTABLE_TO_NON_TEXT,
1091 .handler = extable_mismatch_handler,
1092}
1093};
1094
1095static const struct sectioncheck *section_mismatch(
1096 const char *fromsec, const char *tosec)
1097{
1098 int i;
1099 int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
1100 const struct sectioncheck *check = &sectioncheck[0];
1101
1102 /*
1103 * The target section could be the SHT_NUL section when we're
1104 * handling relocations to un-resolved symbols, trying to match it
1105 * doesn't make much sense and causes build failures on parisc and
1106 * mn10300 architectures.
1107 */
1108 if (*tosec == '\0')
1109 return NULL;
1110
1111 for (i = 0; i < elems; i++) {
1112 if (match(fromsec, check->fromsec)) {
1113 if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
1114 return check;
1115 if (check->good_tosec[0] && !match(tosec, check->good_tosec))
1116 return check;
1117 }
1118 check++;
1119 }
1120 return NULL;
1121}
1122
1123/**
1124 * Whitelist to allow certain references to pass with no warning.
1125 *
1126 * Pattern 1:
1127 * If a module parameter is declared __initdata and permissions=0
1128 * then this is legal despite the warning generated.
1129 * We cannot see value of permissions here, so just ignore
1130 * this pattern.
1131 * The pattern is identified by:
1132 * tosec = .init.data
1133 * fromsec = .data*
1134 * atsym =__param*
1135 *
1136 * Pattern 1a:
1137 * module_param_call() ops can refer to __init set function if permissions=0
1138 * The pattern is identified by:
1139 * tosec = .init.text
1140 * fromsec = .data*
1141 * atsym = __param_ops_*
1142 *
1143 * Pattern 2:
1144 * Many drivers utilise a *driver container with references to
1145 * add, remove, probe functions etc.
1146 * the pattern is identified by:
1147 * tosec = init or exit section
1148 * fromsec = data section
1149 * atsym = *driver, *_template, *_sht, *_ops, *_probe,
1150 * *probe_one, *_console, *_timer
1151 *
1152 * Pattern 3:
1153 * Whitelist all references from .head.text to any init section
1154 *
1155 * Pattern 4:
1156 * Some symbols belong to init section but still it is ok to reference
1157 * these from non-init sections as these symbols don't have any memory
1158 * allocated for them and symbol address and value are same. So even
1159 * if init section is freed, its ok to reference those symbols.
1160 * For ex. symbols marking the init section boundaries.
1161 * This pattern is identified by
1162 * refsymname = __init_begin, _sinittext, _einittext
1163 *
1164 * Pattern 5:
1165 * GCC may optimize static inlines when fed constant arg(s) resulting
1166 * in functions like cpumask_empty() -- generating an associated symbol
1167 * cpumask_empty.constprop.3 that appears in the audit. If the const that
1168 * is passed in comes from __init, like say nmi_ipi_mask, we get a
1169 * meaningless section warning. May need to add isra symbols too...
1170 * This pattern is identified by
1171 * tosec = init section
1172 * fromsec = text section
1173 * refsymname = *.constprop.*
1174 *
1175 **/
1176static int secref_whitelist(const struct sectioncheck *mismatch,
1177 const char *fromsec, const char *fromsym,
1178 const char *tosec, const char *tosym)
1179{
1180 /* Check for pattern 1 */
1181 if (match(tosec, init_data_sections) &&
1182 match(fromsec, data_sections) &&
1183 (strncmp(fromsym, "__param", strlen("__param")) == 0))
1184 return 0;
1185
1186 /* Check for pattern 1a */
1187 if (strcmp(tosec, ".init.text") == 0 &&
1188 match(fromsec, data_sections) &&
1189 (strncmp(fromsym, "__param_ops_", strlen("__param_ops_")) == 0))
1190 return 0;
1191
1192 /* Check for pattern 2 */
1193 if (match(tosec, init_exit_sections) &&
1194 match(fromsec, data_sections) &&
1195 match(fromsym, mismatch->symbol_white_list))
1196 return 0;
1197
1198 /* Check for pattern 3 */
1199 if (match(fromsec, head_sections) &&
1200 match(tosec, init_sections))
1201 return 0;
1202
1203 /* Check for pattern 4 */
1204 if (match(tosym, linker_symbols))
1205 return 0;
1206
1207 /* Check for pattern 5 */
1208 if (match(fromsec, text_sections) &&
1209 match(tosec, init_sections) &&
1210 match(fromsym, optim_symbols))
1211 return 0;
1212
1213 return 1;
1214}
1215
1216/**
1217 * Find symbol based on relocation record info.
1218 * In some cases the symbol supplied is a valid symbol so
1219 * return refsym. If st_name != 0 we assume this is a valid symbol.
1220 * In other cases the symbol needs to be looked up in the symbol table
1221 * based on section and address.
1222 * **/
1223static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
1224 Elf_Sym *relsym)
1225{
1226 Elf_Sym *sym;
1227 Elf_Sym *near = NULL;
1228 Elf64_Sword distance = 20;
1229 Elf64_Sword d;
1230 unsigned int relsym_secindex;
1231
1232 if (relsym->st_name != 0)
1233 return relsym;
1234
1235 relsym_secindex = get_secindex(elf, relsym);
1236 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1237 if (get_secindex(elf, sym) != relsym_secindex)
1238 continue;
1239 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
1240 continue;
1241 if (sym->st_value == addr)
1242 return sym;
1243 /* Find a symbol nearby - addr are maybe negative */
1244 d = sym->st_value - addr;
1245 if (d < 0)
1246 d = addr - sym->st_value;
1247 if (d < distance) {
1248 distance = d;
1249 near = sym;
1250 }
1251 }
1252 /* We need a close match */
1253 if (distance < 20)
1254 return near;
1255 else
1256 return NULL;
1257}
1258
1259static inline int is_arm_mapping_symbol(const char *str)
1260{
1261 return str[0] == '$' && strchr("axtd", str[1])
1262 && (str[2] == '\0' || str[2] == '.');
1263}
1264
1265/*
1266 * If there's no name there, ignore it; likewise, ignore it if it's
1267 * one of the magic symbols emitted used by current ARM tools.
1268 *
1269 * Otherwise if find_symbols_between() returns those symbols, they'll
1270 * fail the whitelist tests and cause lots of false alarms ... fixable
1271 * only by merging __exit and __init sections into __text, bloating
1272 * the kernel (which is especially evil on embedded platforms).
1273 */
1274static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1275{
1276 const char *name = elf->strtab + sym->st_name;
1277
1278 if (!name || !strlen(name))
1279 return 0;
1280 return !is_arm_mapping_symbol(name);
1281}
1282
1283/*
1284 * Find symbols before or equal addr and after addr - in the section sec.
1285 * If we find two symbols with equal offset prefer one with a valid name.
1286 * The ELF format may have a better way to detect what type of symbol
1287 * it is, but this works for now.
1288 **/
1289static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1290 const char *sec)
1291{
1292 Elf_Sym *sym;
1293 Elf_Sym *near = NULL;
1294 Elf_Addr distance = ~0;
1295
1296 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1297 const char *symsec;
1298
1299 if (is_shndx_special(sym->st_shndx))
1300 continue;
1301 symsec = sec_name(elf, get_secindex(elf, sym));
1302 if (strcmp(symsec, sec) != 0)
1303 continue;
1304 if (!is_valid_name(elf, sym))
1305 continue;
1306 if (sym->st_value <= addr) {
1307 if ((addr - sym->st_value) < distance) {
1308 distance = addr - sym->st_value;
1309 near = sym;
1310 } else if ((addr - sym->st_value) == distance) {
1311 near = sym;
1312 }
1313 }
1314 }
1315 return near;
1316}
1317
1318/*
1319 * Convert a section name to the function/data attribute
1320 * .init.text => __init
1321 * .memexitconst => __memconst
1322 * etc.
1323 *
1324 * The memory of returned value has been allocated on a heap. The user of this
1325 * method should free it after usage.
1326*/
1327static char *sec2annotation(const char *s)
1328{
1329 if (match(s, init_exit_sections)) {
1330 char *p = malloc(20);
1331 char *r = p;
1332
1333 *p++ = '_';
1334 *p++ = '_';
1335 if (*s == '.')
1336 s++;
1337 while (*s && *s != '.')
1338 *p++ = *s++;
1339 *p = '\0';
1340 if (*s == '.')
1341 s++;
1342 if (strstr(s, "rodata") != NULL)
1343 strcat(p, "const ");
1344 else if (strstr(s, "data") != NULL)
1345 strcat(p, "data ");
1346 else
1347 strcat(p, " ");
1348 return r;
1349 } else {
1350 return strdup("");
1351 }
1352}
1353
1354static int is_function(Elf_Sym *sym)
1355{
1356 if (sym)
1357 return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1358 else
1359 return -1;
1360}
1361
1362static void print_section_list(const char * const list[20])
1363{
1364 const char *const *s = list;
1365
1366 while (*s) {
1367 fprintf(stderr, "%s", *s);
1368 s++;
1369 if (*s)
1370 fprintf(stderr, ", ");
1371 }
1372 fprintf(stderr, "\n");
1373}
1374
1375static inline void get_pretty_name(int is_func, const char** name, const char** name_p)
1376{
1377 switch (is_func) {
1378 case 0: *name = "variable"; *name_p = ""; break;
1379 case 1: *name = "function"; *name_p = "()"; break;
1380 default: *name = "(unknown reference)"; *name_p = ""; break;
1381 }
1382}
1383
1384/*
1385 * Print a warning about a section mismatch.
1386 * Try to find symbols near it so user can find it.
1387 * Check whitelist before warning - it may be a false positive.
1388 */
1389static void report_sec_mismatch(const char *modname,
1390 const struct sectioncheck *mismatch,
1391 const char *fromsec,
1392 unsigned long long fromaddr,
1393 const char *fromsym,
1394 int from_is_func,
1395 const char *tosec, const char *tosym,
1396 int to_is_func)
1397{
1398 const char *from, *from_p;
1399 const char *to, *to_p;
1400 char *prl_from;
1401 char *prl_to;
1402
1403 sec_mismatch_count++;
1404 if (!sec_mismatch_verbose)
1405 return;
1406
1407 get_pretty_name(from_is_func, &from, &from_p);
1408 get_pretty_name(to_is_func, &to, &to_p);
1409
1410 warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1411 "to the %s %s:%s%s\n",
1412 modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1413 tosym, to_p);
1414
1415 switch (mismatch->mismatch) {
1416 case TEXT_TO_ANY_INIT:
1417 prl_from = sec2annotation(fromsec);
1418 prl_to = sec2annotation(tosec);
1419 fprintf(stderr,
1420 "The function %s%s() references\n"
1421 "the %s %s%s%s.\n"
1422 "This is often because %s lacks a %s\n"
1423 "annotation or the annotation of %s is wrong.\n",
1424 prl_from, fromsym,
1425 to, prl_to, tosym, to_p,
1426 fromsym, prl_to, tosym);
1427 free(prl_from);
1428 free(prl_to);
1429 break;
1430 case DATA_TO_ANY_INIT: {
1431 prl_to = sec2annotation(tosec);
1432 fprintf(stderr,
1433 "The variable %s references\n"
1434 "the %s %s%s%s\n"
1435 "If the reference is valid then annotate the\n"
1436 "variable with __init* or __refdata (see linux/init.h) "
1437 "or name the variable:\n",
1438 fromsym, to, prl_to, tosym, to_p);
1439 print_section_list(mismatch->symbol_white_list);
1440 free(prl_to);
1441 break;
1442 }
1443 case TEXT_TO_ANY_EXIT:
1444 prl_to = sec2annotation(tosec);
1445 fprintf(stderr,
1446 "The function %s() references a %s in an exit section.\n"
1447 "Often the %s %s%s has valid usage outside the exit section\n"
1448 "and the fix is to remove the %sannotation of %s.\n",
1449 fromsym, to, to, tosym, to_p, prl_to, tosym);
1450 free(prl_to);
1451 break;
1452 case DATA_TO_ANY_EXIT: {
1453 prl_to = sec2annotation(tosec);
1454 fprintf(stderr,
1455 "The variable %s references\n"
1456 "the %s %s%s%s\n"
1457 "If the reference is valid then annotate the\n"
1458 "variable with __exit* (see linux/init.h) or "
1459 "name the variable:\n",
1460 fromsym, to, prl_to, tosym, to_p);
1461 print_section_list(mismatch->symbol_white_list);
1462 free(prl_to);
1463 break;
1464 }
1465 case XXXINIT_TO_SOME_INIT:
1466 case XXXEXIT_TO_SOME_EXIT:
1467 prl_from = sec2annotation(fromsec);
1468 prl_to = sec2annotation(tosec);
1469 fprintf(stderr,
1470 "The %s %s%s%s references\n"
1471 "a %s %s%s%s.\n"
1472 "If %s is only used by %s then\n"
1473 "annotate %s with a matching annotation.\n",
1474 from, prl_from, fromsym, from_p,
1475 to, prl_to, tosym, to_p,
1476 tosym, fromsym, tosym);
1477 free(prl_from);
1478 free(prl_to);
1479 break;
1480 case ANY_INIT_TO_ANY_EXIT:
1481 prl_from = sec2annotation(fromsec);
1482 prl_to = sec2annotation(tosec);
1483 fprintf(stderr,
1484 "The %s %s%s%s references\n"
1485 "a %s %s%s%s.\n"
1486 "This is often seen when error handling "
1487 "in the init function\n"
1488 "uses functionality in the exit path.\n"
1489 "The fix is often to remove the %sannotation of\n"
1490 "%s%s so it may be used outside an exit section.\n",
1491 from, prl_from, fromsym, from_p,
1492 to, prl_to, tosym, to_p,
1493 prl_to, tosym, to_p);
1494 free(prl_from);
1495 free(prl_to);
1496 break;
1497 case ANY_EXIT_TO_ANY_INIT:
1498 prl_from = sec2annotation(fromsec);
1499 prl_to = sec2annotation(tosec);
1500 fprintf(stderr,
1501 "The %s %s%s%s references\n"
1502 "a %s %s%s%s.\n"
1503 "This is often seen when error handling "
1504 "in the exit function\n"
1505 "uses functionality in the init path.\n"
1506 "The fix is often to remove the %sannotation of\n"
1507 "%s%s so it may be used outside an init section.\n",
1508 from, prl_from, fromsym, from_p,
1509 to, prl_to, tosym, to_p,
1510 prl_to, tosym, to_p);
1511 free(prl_from);
1512 free(prl_to);
1513 break;
1514 case EXPORT_TO_INIT_EXIT:
1515 prl_to = sec2annotation(tosec);
1516 fprintf(stderr,
1517 "The symbol %s is exported and annotated %s\n"
1518 "Fix this by removing the %sannotation of %s "
1519 "or drop the export.\n",
1520 tosym, prl_to, prl_to, tosym);
1521 free(prl_to);
1522 break;
1523 case EXTABLE_TO_NON_TEXT:
1524 fatal("There's a special handler for this mismatch type, "
1525 "we should never get here.");
1526 break;
1527 }
1528 fprintf(stderr, "\n");
1529}
1530
1531static void default_mismatch_handler(const char *modname, struct elf_info *elf,
1532 const struct sectioncheck* const mismatch,
1533 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1534{
1535 const char *tosec;
1536 Elf_Sym *to;
1537 Elf_Sym *from;
1538 const char *tosym;
1539 const char *fromsym;
1540
1541 from = find_elf_symbol2(elf, r->r_offset, fromsec);
1542 fromsym = sym_name(elf, from);
1543
1544 if (!strncmp(fromsym, "reference___initcall",
1545 sizeof("reference___initcall")-1))
1546 return;
1547
1548 tosec = sec_name(elf, get_secindex(elf, sym));
1549 to = find_elf_symbol(elf, r->r_addend, sym);
1550 tosym = sym_name(elf, to);
1551
1552 /* check whitelist - we may ignore it */
1553 if (secref_whitelist(mismatch,
1554 fromsec, fromsym, tosec, tosym)) {
1555 report_sec_mismatch(modname, mismatch,
1556 fromsec, r->r_offset, fromsym,
1557 is_function(from), tosec, tosym,
1558 is_function(to));
1559 }
1560}
1561
1562static int is_executable_section(struct elf_info* elf, unsigned int section_index)
1563{
1564 if (section_index > elf->num_sections)
1565 fatal("section_index is outside elf->num_sections!\n");
1566
1567 return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR);
1568}
1569
1570/*
1571 * We rely on a gross hack in section_rel[a]() calling find_extable_entry_size()
1572 * to know the sizeof(struct exception_table_entry) for the target architecture.
1573 */
1574static unsigned int extable_entry_size = 0;
1575static void find_extable_entry_size(const char* const sec, const Elf_Rela* r)
1576{
1577 /*
1578 * If we're currently checking the second relocation within __ex_table,
1579 * that relocation offset tells us the offsetof(struct
1580 * exception_table_entry, fixup) which is equal to sizeof(struct
1581 * exception_table_entry) divided by two. We use that to our advantage
1582 * since there's no portable way to get that size as every architecture
1583 * seems to go with different sized types. Not pretty but better than
1584 * hard-coding the size for every architecture..
1585 */
1586 if (!extable_entry_size)
1587 extable_entry_size = r->r_offset * 2;
1588}
1589
1590static inline bool is_extable_fault_address(Elf_Rela *r)
1591{
1592 /*
1593 * extable_entry_size is only discovered after we've handled the
1594 * _second_ relocation in __ex_table, so only abort when we're not
1595 * handling the first reloc and extable_entry_size is zero.
1596 */
1597 if (r->r_offset && extable_entry_size == 0)
1598 fatal("extable_entry size hasn't been discovered!\n");
1599
1600 return ((r->r_offset == 0) ||
1601 (r->r_offset % extable_entry_size == 0));
1602}
1603
1604#define is_second_extable_reloc(Start, Cur, Sec) \
1605 (((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0))
1606
1607static void report_extable_warnings(const char* modname, struct elf_info* elf,
1608 const struct sectioncheck* const mismatch,
1609 Elf_Rela* r, Elf_Sym* sym,
1610 const char* fromsec, const char* tosec)
1611{
1612 Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec);
1613 const char* fromsym_name = sym_name(elf, fromsym);
1614 Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym);
1615 const char* tosym_name = sym_name(elf, tosym);
1616 const char* from_pretty_name;
1617 const char* from_pretty_name_p;
1618 const char* to_pretty_name;
1619 const char* to_pretty_name_p;
1620
1621 get_pretty_name(is_function(fromsym),
1622 &from_pretty_name, &from_pretty_name_p);
1623 get_pretty_name(is_function(tosym),
1624 &to_pretty_name, &to_pretty_name_p);
1625
1626 warn("%s(%s+0x%lx): Section mismatch in reference"
1627 " from the %s %s%s to the %s %s:%s%s\n",
1628 modname, fromsec, (long)r->r_offset, from_pretty_name,
1629 fromsym_name, from_pretty_name_p,
1630 to_pretty_name, tosec, tosym_name, to_pretty_name_p);
1631
1632 if (!match(tosec, mismatch->bad_tosec) &&
1633 is_executable_section(elf, get_secindex(elf, sym)))
1634 fprintf(stderr,
1635 "The relocation at %s+0x%lx references\n"
1636 "section \"%s\" which is not in the list of\n"
1637 "authorized sections. If you're adding a new section\n"
1638 "and/or if this reference is valid, add \"%s\" to the\n"
1639 "list of authorized sections to jump to on fault.\n"
1640 "This can be achieved by adding \"%s\" to \n"
1641 "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
1642 fromsec, (long)r->r_offset, tosec, tosec, tosec);
1643}
1644
1645static void extable_mismatch_handler(const char* modname, struct elf_info *elf,
1646 const struct sectioncheck* const mismatch,
1647 Elf_Rela* r, Elf_Sym* sym,
1648 const char *fromsec)
1649{
1650 const char* tosec = sec_name(elf, get_secindex(elf, sym));
1651
1652 sec_mismatch_count++;
1653
1654 if (sec_mismatch_verbose)
1655 report_extable_warnings(modname, elf, mismatch, r, sym,
1656 fromsec, tosec);
1657
1658 if (match(tosec, mismatch->bad_tosec))
1659 fatal("The relocation at %s+0x%lx references\n"
1660 "section \"%s\" which is black-listed.\n"
1661 "Something is seriously wrong and should be fixed.\n"
1662 "You might get more information about where this is\n"
1663 "coming from by using scripts/check_extable.sh %s\n",
1664 fromsec, (long)r->r_offset, tosec, modname);
1665 else if (!is_executable_section(elf, get_secindex(elf, sym))) {
1666 if (is_extable_fault_address(r))
1667 fatal("The relocation at %s+0x%lx references\n"
1668 "section \"%s\" which is not executable, IOW\n"
1669 "it is not possible for the kernel to fault\n"
1670 "at that address. Something is seriously wrong\n"
1671 "and should be fixed.\n",
1672 fromsec, (long)r->r_offset, tosec);
1673 else
1674 fatal("The relocation at %s+0x%lx references\n"
1675 "section \"%s\" which is not executable, IOW\n"
1676 "the kernel will fault if it ever tries to\n"
1677 "jump to it. Something is seriously wrong\n"
1678 "and should be fixed.\n",
1679 fromsec, (long)r->r_offset, tosec);
1680 }
1681}
1682
1683static void check_section_mismatch(const char *modname, struct elf_info *elf,
1684 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1685{
1686 const char *tosec = sec_name(elf, get_secindex(elf, sym));;
1687 const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec);
1688
1689 if (mismatch) {
1690 if (mismatch->handler)
1691 mismatch->handler(modname, elf, mismatch,
1692 r, sym, fromsec);
1693 else
1694 default_mismatch_handler(modname, elf, mismatch,
1695 r, sym, fromsec);
1696 }
1697}
1698
1699static unsigned int *reloc_location(struct elf_info *elf,
1700 Elf_Shdr *sechdr, Elf_Rela *r)
1701{
1702 Elf_Shdr *sechdrs = elf->sechdrs;
1703 int section = sechdr->sh_info;
1704
1705 return (void *)elf->hdr + sechdrs[section].sh_offset +
1706 r->r_offset;
1707}
1708
1709static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1710{
1711 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1712 unsigned int *location = reloc_location(elf, sechdr, r);
1713
1714 switch (r_typ) {
1715 case R_386_32:
1716 r->r_addend = TO_NATIVE(*location);
1717 break;
1718 case R_386_PC32:
1719 r->r_addend = TO_NATIVE(*location) + 4;
1720 /* For CONFIG_RELOCATABLE=y */
1721 if (elf->hdr->e_type == ET_EXEC)
1722 r->r_addend += r->r_offset;
1723 break;
1724 }
1725 return 0;
1726}
1727
1728#ifndef R_ARM_CALL
1729#define R_ARM_CALL 28
1730#endif
1731#ifndef R_ARM_JUMP24
1732#define R_ARM_JUMP24 29
1733#endif
1734
1735#ifndef R_ARM_THM_CALL
1736#define R_ARM_THM_CALL 10
1737#endif
1738#ifndef R_ARM_THM_JUMP24
1739#define R_ARM_THM_JUMP24 30
1740#endif
1741#ifndef R_ARM_THM_JUMP19
1742#define R_ARM_THM_JUMP19 51
1743#endif
1744
1745static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1746{
1747 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1748
1749 switch (r_typ) {
1750 case R_ARM_ABS32:
1751 /* From ARM ABI: (S + A) | T */
1752 r->r_addend = (int)(long)
1753 (elf->symtab_start + ELF_R_SYM(r->r_info));
1754 break;
1755 case R_ARM_PC24:
1756 case R_ARM_CALL:
1757 case R_ARM_JUMP24:
1758 case R_ARM_THM_CALL:
1759 case R_ARM_THM_JUMP24:
1760 case R_ARM_THM_JUMP19:
1761 /* From ARM ABI: ((S + A) | T) - P */
1762 r->r_addend = (int)(long)(elf->hdr +
1763 sechdr->sh_offset +
1764 (r->r_offset - sechdr->sh_addr));
1765 break;
1766 default:
1767 return 1;
1768 }
1769 return 0;
1770}
1771
1772static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1773{
1774 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1775 unsigned int *location = reloc_location(elf, sechdr, r);
1776 unsigned int inst;
1777
1778 if (r_typ == R_MIPS_HI16)
1779 return 1; /* skip this */
1780 inst = TO_NATIVE(*location);
1781 switch (r_typ) {
1782 case R_MIPS_LO16:
1783 r->r_addend = inst & 0xffff;
1784 break;
1785 case R_MIPS_26:
1786 r->r_addend = (inst & 0x03ffffff) << 2;
1787 break;
1788 case R_MIPS_32:
1789 r->r_addend = inst;
1790 break;
1791 }
1792 return 0;
1793}
1794
1795static void section_rela(const char *modname, struct elf_info *elf,
1796 Elf_Shdr *sechdr)
1797{
1798 Elf_Sym *sym;
1799 Elf_Rela *rela;
1800 Elf_Rela r;
1801 unsigned int r_sym;
1802 const char *fromsec;
1803
1804 Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1805 Elf_Rela *stop = (void *)start + sechdr->sh_size;
1806
1807 fromsec = sech_name(elf, sechdr);
1808 fromsec += strlen(".rela");
1809 /* if from section (name) is know good then skip it */
1810 if (match(fromsec, section_white_list))
1811 return;
1812
1813 for (rela = start; rela < stop; rela++) {
1814 r.r_offset = TO_NATIVE(rela->r_offset);
1815#if KERNEL_ELFCLASS == ELFCLASS64
1816 if (elf->hdr->e_machine == EM_MIPS) {
1817 unsigned int r_typ;
1818 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1819 r_sym = TO_NATIVE(r_sym);
1820 r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1821 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1822 } else {
1823 r.r_info = TO_NATIVE(rela->r_info);
1824 r_sym = ELF_R_SYM(r.r_info);
1825 }
1826#else
1827 r.r_info = TO_NATIVE(rela->r_info);
1828 r_sym = ELF_R_SYM(r.r_info);
1829#endif
1830 r.r_addend = TO_NATIVE(rela->r_addend);
1831 sym = elf->symtab_start + r_sym;
1832 /* Skip special sections */
1833 if (is_shndx_special(sym->st_shndx))
1834 continue;
1835 if (is_second_extable_reloc(start, rela, fromsec))
1836 find_extable_entry_size(fromsec, &r);
1837 check_section_mismatch(modname, elf, &r, sym, fromsec);
1838 }
1839}
1840
1841static void section_rel(const char *modname, struct elf_info *elf,
1842 Elf_Shdr *sechdr)
1843{
1844 Elf_Sym *sym;
1845 Elf_Rel *rel;
1846 Elf_Rela r;
1847 unsigned int r_sym;
1848 const char *fromsec;
1849
1850 Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1851 Elf_Rel *stop = (void *)start + sechdr->sh_size;
1852
1853 fromsec = sech_name(elf, sechdr);
1854 fromsec += strlen(".rel");
1855 /* if from section (name) is know good then skip it */
1856 if (match(fromsec, section_white_list))
1857 return;
1858
1859 for (rel = start; rel < stop; rel++) {
1860 r.r_offset = TO_NATIVE(rel->r_offset);
1861#if KERNEL_ELFCLASS == ELFCLASS64
1862 if (elf->hdr->e_machine == EM_MIPS) {
1863 unsigned int r_typ;
1864 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1865 r_sym = TO_NATIVE(r_sym);
1866 r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1867 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1868 } else {
1869 r.r_info = TO_NATIVE(rel->r_info);
1870 r_sym = ELF_R_SYM(r.r_info);
1871 }
1872#else
1873 r.r_info = TO_NATIVE(rel->r_info);
1874 r_sym = ELF_R_SYM(r.r_info);
1875#endif
1876 r.r_addend = 0;
1877 switch (elf->hdr->e_machine) {
1878 case EM_386:
1879 if (addend_386_rel(elf, sechdr, &r))
1880 continue;
1881 break;
1882 case EM_ARM:
1883 if (addend_arm_rel(elf, sechdr, &r))
1884 continue;
1885 break;
1886 case EM_MIPS:
1887 if (addend_mips_rel(elf, sechdr, &r))
1888 continue;
1889 break;
1890 }
1891 sym = elf->symtab_start + r_sym;
1892 /* Skip special sections */
1893 if (is_shndx_special(sym->st_shndx))
1894 continue;
1895 if (is_second_extable_reloc(start, rel, fromsec))
1896 find_extable_entry_size(fromsec, &r);
1897 check_section_mismatch(modname, elf, &r, sym, fromsec);
1898 }
1899}
1900
1901/**
1902 * A module includes a number of sections that are discarded
1903 * either when loaded or when used as built-in.
1904 * For loaded modules all functions marked __init and all data
1905 * marked __initdata will be discarded when the module has been initialized.
1906 * Likewise for modules used built-in the sections marked __exit
1907 * are discarded because __exit marked function are supposed to be called
1908 * only when a module is unloaded which never happens for built-in modules.
1909 * The check_sec_ref() function traverses all relocation records
1910 * to find all references to a section that reference a section that will
1911 * be discarded and warns about it.
1912 **/
1913static void check_sec_ref(struct module *mod, const char *modname,
1914 struct elf_info *elf)
1915{
1916 int i;
1917 Elf_Shdr *sechdrs = elf->sechdrs;
1918
1919 /* Walk through all sections */
1920 for (i = 0; i < elf->num_sections; i++) {
1921 check_section(modname, elf, &elf->sechdrs[i]);
1922 /* We want to process only relocation sections and not .init */
1923 if (sechdrs[i].sh_type == SHT_RELA)
1924 section_rela(modname, elf, &elf->sechdrs[i]);
1925 else if (sechdrs[i].sh_type == SHT_REL)
1926 section_rel(modname, elf, &elf->sechdrs[i]);
1927 }
1928}
1929
1930static char *remove_dot(char *s)
1931{
1932 size_t n = strcspn(s, ".");
1933
1934 if (n && s[n]) {
1935 size_t m = strspn(s + n + 1, "0123456789");
1936 if (m && (s[n + m] == '.' || s[n + m] == 0))
1937 s[n] = 0;
1938 }
1939 return s;
1940}
1941
1942static void read_symbols(char *modname)
1943{
1944 const char *symname;
1945 char *version;
1946 char *license;
1947 struct module *mod;
1948 struct elf_info info = { };
1949 Elf_Sym *sym;
1950
1951 if (!parse_elf(&info, modname))
1952 return;
1953
1954 mod = new_module(modname);
1955
1956 /* When there's no vmlinux, don't print warnings about
1957 * unresolved symbols (since there'll be too many ;) */
1958 if (is_vmlinux(modname)) {
1959 have_vmlinux = 1;
1960 mod->skip = 1;
1961 }
1962
1963 license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1964 if (info.modinfo && !license && !is_vmlinux(modname))
1965 warn("modpost: missing MODULE_LICENSE() in %s\n"
1966 "see include/linux/module.h for "
1967 "more information\n", modname);
1968 while (license) {
1969 if (license_is_gpl_compatible(license))
1970 mod->gpl_compatible = 1;
1971 else {
1972 mod->gpl_compatible = 0;
1973 break;
1974 }
1975 license = get_next_modinfo(info.modinfo, info.modinfo_len,
1976 "license", license);
1977 }
1978
1979 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1980 symname = remove_dot(info.strtab + sym->st_name);
1981
1982 handle_modversions(mod, &info, sym, symname);
1983 handle_moddevtable(mod, &info, sym, symname);
1984 }
1985 if (!is_vmlinux(modname) ||
1986 (is_vmlinux(modname) && vmlinux_section_warnings))
1987 check_sec_ref(mod, modname, &info);
1988
1989 version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1990 if (version)
1991 maybe_frob_rcs_version(modname, version, info.modinfo,
1992 version - (char *)info.hdr);
1993 if (version || (all_versions && !is_vmlinux(modname)))
1994 get_src_version(modname, mod->srcversion,
1995 sizeof(mod->srcversion)-1);
1996
1997 parse_elf_finish(&info);
1998
1999 /* Our trick to get versioning for module struct etc. - it's
2000 * never passed as an argument to an exported function, so
2001 * the automatic versioning doesn't pick it up, but it's really
2002 * important anyhow */
2003 if (modversions)
2004 mod->unres = alloc_symbol("module_layout", 0, mod->unres);
2005}
2006
2007static void read_symbols_from_files(const char *filename)
2008{
2009 FILE *in = stdin;
2010 char fname[PATH_MAX];
2011
2012 if (strcmp(filename, "-") != 0) {
2013 in = fopen(filename, "r");
2014 if (!in)
2015 fatal("Can't open filenames file %s: %m", filename);
2016 }
2017
2018 while (fgets(fname, PATH_MAX, in) != NULL) {
2019 if (strends(fname, "\n"))
2020 fname[strlen(fname)-1] = '\0';
2021 read_symbols(fname);
2022 }
2023
2024 if (in != stdin)
2025 fclose(in);
2026}
2027
2028#define SZ 500
2029
2030/* We first write the generated file into memory using the
2031 * following helper, then compare to the file on disk and
2032 * only update the later if anything changed */
2033
2034void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
2035 const char *fmt, ...)
2036{
2037 char tmp[SZ];
2038 int len;
2039 va_list ap;
2040
2041 va_start(ap, fmt);
2042 len = vsnprintf(tmp, SZ, fmt, ap);
2043 buf_write(buf, tmp, len);
2044 va_end(ap);
2045}
2046
2047void buf_write(struct buffer *buf, const char *s, int len)
2048{
2049 if (buf->size - buf->pos < len) {
2050 buf->size += len + SZ;
2051 buf->p = realloc(buf->p, buf->size);
2052 }
2053 strncpy(buf->p + buf->pos, s, len);
2054 buf->pos += len;
2055}
2056
2057static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
2058{
2059 const char *e = is_vmlinux(m) ?"":".ko";
2060
2061 switch (exp) {
2062 case export_gpl:
2063 fatal("modpost: GPL-incompatible module %s%s "
2064 "uses GPL-only symbol '%s'\n", m, e, s);
2065 break;
2066 case export_unused_gpl:
2067 fatal("modpost: GPL-incompatible module %s%s "
2068 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
2069 break;
2070 case export_gpl_future:
2071 warn("modpost: GPL-incompatible module %s%s "
2072 "uses future GPL-only symbol '%s'\n", m, e, s);
2073 break;
2074 case export_plain:
2075 case export_unused:
2076 case export_unknown:
2077 /* ignore */
2078 break;
2079 }
2080}
2081
2082static void check_for_unused(enum export exp, const char *m, const char *s)
2083{
2084 const char *e = is_vmlinux(m) ?"":".ko";
2085
2086 switch (exp) {
2087 case export_unused:
2088 case export_unused_gpl:
2089 warn("modpost: module %s%s "
2090 "uses symbol '%s' marked UNUSED\n", m, e, s);
2091 break;
2092 default:
2093 /* ignore */
2094 break;
2095 }
2096}
2097
2098static void check_exports(struct module *mod)
2099{
2100 struct symbol *s, *exp;
2101
2102 for (s = mod->unres; s; s = s->next) {
2103 const char *basename;
2104 exp = find_symbol(s->name);
2105 if (!exp || exp->module == mod)
2106 continue;
2107 basename = strrchr(mod->name, '/');
2108 if (basename)
2109 basename++;
2110 else
2111 basename = mod->name;
2112 if (!mod->gpl_compatible)
2113 check_for_gpl_usage(exp->export, basename, exp->name);
2114 check_for_unused(exp->export, basename, exp->name);
2115 }
2116}
2117
2118/**
2119 * Header for the generated file
2120 **/
2121static void add_header(struct buffer *b, struct module *mod)
2122{
2123 buf_printf(b, "#include <linux/module.h>\n");
2124 buf_printf(b, "#include <linux/vermagic.h>\n");
2125 buf_printf(b, "#include <linux/compiler.h>\n");
2126 buf_printf(b, "\n");
2127 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
2128 buf_printf(b, "\n");
2129 buf_printf(b, "__visible struct module __this_module\n");
2130 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
2131 buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
2132 if (mod->has_init)
2133 buf_printf(b, "\t.init = init_module,\n");
2134 if (mod->has_cleanup)
2135 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
2136 "\t.exit = cleanup_module,\n"
2137 "#endif\n");
2138 buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
2139 buf_printf(b, "};\n");
2140}
2141
2142static void add_intree_flag(struct buffer *b, int is_intree)
2143{
2144 if (is_intree)
2145 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
2146}
2147
2148static void add_staging_flag(struct buffer *b, const char *name)
2149{
2150 static const char *staging_dir = "drivers/staging";
2151
2152 if (strncmp(staging_dir, name, strlen(staging_dir)) == 0)
2153 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
2154}
2155
2156/* In kernel, this size is defined in linux/module.h;
2157 * here we use Elf_Addr instead of long for covering cross-compile
2158 */
2159#define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
2160
2161/**
2162 * Record CRCs for unresolved symbols
2163 **/
2164static int add_versions(struct buffer *b, struct module *mod)
2165{
2166 struct symbol *s, *exp;
2167 int err = 0;
2168
2169 for (s = mod->unres; s; s = s->next) {
2170 exp = find_symbol(s->name);
2171 if (!exp || exp->module == mod) {
2172 if (have_vmlinux && !s->weak) {
2173 if (warn_unresolved) {
2174 warn("\"%s\" [%s.ko] undefined!\n",
2175 s->name, mod->name);
2176 } else {
2177 merror("\"%s\" [%s.ko] undefined!\n",
2178 s->name, mod->name);
2179 err = 1;
2180 }
2181 }
2182 continue;
2183 }
2184 s->module = exp->module;
2185 s->crc_valid = exp->crc_valid;
2186 s->crc = exp->crc;
2187 }
2188
2189 if (!modversions)
2190 return err;
2191
2192 buf_printf(b, "\n");
2193 buf_printf(b, "static const struct modversion_info ____versions[]\n");
2194 buf_printf(b, "__used\n");
2195 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
2196
2197 for (s = mod->unres; s; s = s->next) {
2198 if (!s->module)
2199 continue;
2200 if (!s->crc_valid) {
2201 warn("\"%s\" [%s.ko] has no CRC!\n",
2202 s->name, mod->name);
2203 continue;
2204 }
2205 if (strlen(s->name) >= MODULE_NAME_LEN) {
2206 merror("too long symbol \"%s\" [%s.ko]\n",
2207 s->name, mod->name);
2208 err = 1;
2209 break;
2210 }
2211 buf_printf(b, "\t{ %#8x, __VMLINUX_SYMBOL_STR(%s) },\n",
2212 s->crc, s->name);
2213 }
2214
2215 buf_printf(b, "};\n");
2216
2217 return err;
2218}
2219
2220static void add_depends(struct buffer *b, struct module *mod,
2221 struct module *modules)
2222{
2223 struct symbol *s;
2224 struct module *m;
2225 int first = 1;
2226
2227 for (m = modules; m; m = m->next)
2228 m->seen = is_vmlinux(m->name);
2229
2230 buf_printf(b, "\n");
2231 buf_printf(b, "static const char __module_depends[]\n");
2232 buf_printf(b, "__used\n");
2233 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
2234 buf_printf(b, "\"depends=");
2235 for (s = mod->unres; s; s = s->next) {
2236 const char *p;
2237 if (!s->module)
2238 continue;
2239
2240 if (s->module->seen)
2241 continue;
2242
2243 s->module->seen = 1;
2244 p = strrchr(s->module->name, '/');
2245 if (p)
2246 p++;
2247 else
2248 p = s->module->name;
2249 buf_printf(b, "%s%s", first ? "" : ",", p);
2250 first = 0;
2251 }
2252 buf_printf(b, "\";\n");
2253}
2254
2255static void add_srcversion(struct buffer *b, struct module *mod)
2256{
2257 if (mod->srcversion[0]) {
2258 buf_printf(b, "\n");
2259 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
2260 mod->srcversion);
2261 }
2262}
2263
2264static void write_if_changed(struct buffer *b, const char *fname)
2265{
2266 char *tmp;
2267 FILE *file;
2268 struct stat st;
2269
2270 file = fopen(fname, "r");
2271 if (!file)
2272 goto write;
2273
2274 if (fstat(fileno(file), &st) < 0)
2275 goto close_write;
2276
2277 if (st.st_size != b->pos)
2278 goto close_write;
2279
2280 tmp = NOFAIL(malloc(b->pos));
2281 if (fread(tmp, 1, b->pos, file) != b->pos)
2282 goto free_write;
2283
2284 if (memcmp(tmp, b->p, b->pos) != 0)
2285 goto free_write;
2286
2287 free(tmp);
2288 fclose(file);
2289 return;
2290
2291 free_write:
2292 free(tmp);
2293 close_write:
2294 fclose(file);
2295 write:
2296 file = fopen(fname, "w");
2297 if (!file) {
2298 perror(fname);
2299 exit(1);
2300 }
2301 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
2302 perror(fname);
2303 exit(1);
2304 }
2305 fclose(file);
2306}
2307
2308/* parse Module.symvers file. line format:
2309 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
2310 **/
2311static void read_dump(const char *fname, unsigned int kernel)
2312{
2313 unsigned long size, pos = 0;
2314 void *file = grab_file(fname, &size);
2315 char *line;
2316
2317 if (!file)
2318 /* No symbol versions, silently ignore */
2319 return;
2320
2321 while ((line = get_next_line(&pos, file, size))) {
2322 char *symname, *modname, *d, *export, *end;
2323 unsigned int crc;
2324 struct module *mod;
2325 struct symbol *s;
2326
2327 if (!(symname = strchr(line, '\t')))
2328 goto fail;
2329 *symname++ = '\0';
2330 if (!(modname = strchr(symname, '\t')))
2331 goto fail;
2332 *modname++ = '\0';
2333 if ((export = strchr(modname, '\t')) != NULL)
2334 *export++ = '\0';
2335 if (export && ((end = strchr(export, '\t')) != NULL))
2336 *end = '\0';
2337 crc = strtoul(line, &d, 16);
2338 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2339 goto fail;
2340 mod = find_module(modname);
2341 if (!mod) {
2342 if (is_vmlinux(modname))
2343 have_vmlinux = 1;
2344 mod = new_module(modname);
2345 mod->skip = 1;
2346 }
2347 s = sym_add_exported(symname, mod, export_no(export));
2348 s->kernel = kernel;
2349 s->preloaded = 1;
2350 sym_update_crc(symname, mod, crc, export_no(export));
2351 }
2352 release_file(file, size);
2353 return;
2354fail:
2355 release_file(file, size);
2356 fatal("parse error in symbol dump file\n");
2357}
2358
2359/* For normal builds always dump all symbols.
2360 * For external modules only dump symbols
2361 * that are not read from kernel Module.symvers.
2362 **/
2363static int dump_sym(struct symbol *sym)
2364{
2365 if (!external_module)
2366 return 1;
2367 if (sym->vmlinux || sym->kernel)
2368 return 0;
2369 return 1;
2370}
2371
2372static void write_dump(const char *fname)
2373{
2374 struct buffer buf = { };
2375 struct symbol *symbol;
2376 int n;
2377
2378 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
2379 symbol = symbolhash[n];
2380 while (symbol) {
2381 if (dump_sym(symbol))
2382 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
2383 symbol->crc, symbol->name,
2384 symbol->module->name,
2385 export_str(symbol->export));
2386 symbol = symbol->next;
2387 }
2388 }
2389 write_if_changed(&buf, fname);
2390 free(buf.p);
2391}
2392
2393struct ext_sym_list {
2394 struct ext_sym_list *next;
2395 const char *file;
2396};
2397
2398int main(int argc, char **argv)
2399{
2400 struct module *mod;
2401 struct buffer buf = { };
2402 char *kernel_read = NULL, *module_read = NULL;
2403 char *dump_write = NULL, *files_source = NULL;
2404 int opt;
2405 int err;
2406 struct ext_sym_list *extsym_iter;
2407 struct ext_sym_list *extsym_start = NULL;
2408
2409 while ((opt = getopt(argc, argv, "i:I:e:mnsST:o:awM:K:E")) != -1) {
2410 switch (opt) {
2411 case 'i':
2412 kernel_read = optarg;
2413 break;
2414 case 'I':
2415 module_read = optarg;
2416 external_module = 1;
2417 break;
2418 case 'e':
2419 external_module = 1;
2420 extsym_iter =
2421 NOFAIL(malloc(sizeof(*extsym_iter)));
2422 extsym_iter->next = extsym_start;
2423 extsym_iter->file = optarg;
2424 extsym_start = extsym_iter;
2425 break;
2426 case 'm':
2427 modversions = 1;
2428 break;
2429 case 'n':
2430 ignore_missing_files = 1;
2431 break;
2432 case 'o':
2433 dump_write = optarg;
2434 break;
2435 case 'a':
2436 all_versions = 1;
2437 break;
2438 case 's':
2439 vmlinux_section_warnings = 0;
2440 break;
2441 case 'S':
2442 sec_mismatch_verbose = 0;
2443 break;
2444 case 'T':
2445 files_source = optarg;
2446 break;
2447 case 'w':
2448 warn_unresolved = 1;
2449 break;
2450 case 'E':
2451 sec_mismatch_fatal = 1;
2452 break;
2453 default:
2454 exit(1);
2455 }
2456 }
2457
2458 if (kernel_read)
2459 read_dump(kernel_read, 1);
2460 if (module_read)
2461 read_dump(module_read, 0);
2462 while (extsym_start) {
2463 read_dump(extsym_start->file, 0);
2464 extsym_iter = extsym_start->next;
2465 free(extsym_start);
2466 extsym_start = extsym_iter;
2467 }
2468
2469 while (optind < argc)
2470 read_symbols(argv[optind++]);
2471
2472 if (files_source)
2473 read_symbols_from_files(files_source);
2474
2475 for (mod = modules; mod; mod = mod->next) {
2476 if (mod->skip)
2477 continue;
2478 check_exports(mod);
2479 }
2480
2481 err = 0;
2482
2483 for (mod = modules; mod; mod = mod->next) {
2484 char fname[PATH_MAX];
2485
2486 if (mod->skip)
2487 continue;
2488
2489 buf.pos = 0;
2490
2491 add_header(&buf, mod);
2492 add_intree_flag(&buf, !external_module);
2493 add_staging_flag(&buf, mod->name);
2494 err |= add_versions(&buf, mod);
2495 add_depends(&buf, mod, modules);
2496 add_moddevtable(&buf, mod);
2497 add_srcversion(&buf, mod);
2498
2499 sprintf(fname, "%s.mod.c", mod->name);
2500 write_if_changed(&buf, fname);
2501 }
2502 if (dump_write)
2503 write_dump(dump_write);
2504 if (sec_mismatch_count) {
2505 if (!sec_mismatch_verbose) {
2506 warn("modpost: Found %d section mismatch(es).\n"
2507 "To see full details build your kernel with:\n"
2508 "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n",
2509 sec_mismatch_count);
2510 }
2511 if (sec_mismatch_fatal) {
2512 fatal("modpost: Section mismatches detected.\n"
2513 "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");
2514 }
2515 }
2516 free(buf.p);
2517
2518 return err;
2519}