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 <elf.h>
16 #include <fnmatch.h>
17 #include <stdio.h>
18 #include <ctype.h>
19 #include <string.h>
20 #include <limits.h>
21 #include <stdbool.h>
22 #include <errno.h>
23 #include "modpost.h"
24 #include "../../include/linux/license.h"
25
26 static bool module_enabled;
27 /* Are we using CONFIG_MODVERSIONS? */
28 static bool modversions;
29 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */
30 static bool all_versions;
31 /* If we are modposting external module set to 1 */
32 static bool external_module;
33 /* Only warn about unresolved symbols */
34 static bool warn_unresolved;
35
36 static int sec_mismatch_count;
37 static bool sec_mismatch_warn_only = true;
38 /* Trim EXPORT_SYMBOLs that are unused by in-tree modules */
39 static bool trim_unused_exports;
40
41 /* ignore missing files */
42 static bool ignore_missing_files;
43 /* If set to 1, only warn (instead of error) about missing ns imports */
44 static bool allow_missing_ns_imports;
45
46 static bool error_occurred;
47
48 static bool extra_warn;
49
50 /*
51 * Cut off the warnings when there are too many. This typically occurs when
52 * vmlinux is missing. ('make modules' without building vmlinux.)
53 */
54 #define MAX_UNRESOLVED_REPORTS 10
55 static unsigned int nr_unresolved;
56
57 /* In kernel, this size is defined in linux/module.h;
58 * here we use Elf_Addr instead of long for covering cross-compile
59 */
60
61 #define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
62
63 void __attribute__((format(printf, 2, 3)))
modpost_log(enum loglevel loglevel,const char * fmt,...)64 modpost_log(enum loglevel loglevel, const char *fmt, ...)
65 {
66 va_list arglist;
67
68 switch (loglevel) {
69 case LOG_WARN:
70 fprintf(stderr, "WARNING: ");
71 break;
72 case LOG_ERROR:
73 fprintf(stderr, "ERROR: ");
74 break;
75 case LOG_FATAL:
76 fprintf(stderr, "FATAL: ");
77 break;
78 default: /* invalid loglevel, ignore */
79 break;
80 }
81
82 fprintf(stderr, "modpost: ");
83
84 va_start(arglist, fmt);
85 vfprintf(stderr, fmt, arglist);
86 va_end(arglist);
87
88 if (loglevel == LOG_FATAL)
89 exit(1);
90 if (loglevel == LOG_ERROR)
91 error_occurred = true;
92 }
93
strends(const char * str,const char * postfix)94 static inline bool strends(const char *str, const char *postfix)
95 {
96 if (strlen(str) < strlen(postfix))
97 return false;
98
99 return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0;
100 }
101
do_nofail(void * ptr,const char * expr)102 void *do_nofail(void *ptr, const char *expr)
103 {
104 if (!ptr)
105 fatal("Memory allocation failure: %s.\n", expr);
106
107 return ptr;
108 }
109
read_text_file(const char * filename)110 char *read_text_file(const char *filename)
111 {
112 struct stat st;
113 size_t nbytes;
114 int fd;
115 char *buf;
116
117 fd = open(filename, O_RDONLY);
118 if (fd < 0) {
119 perror(filename);
120 exit(1);
121 }
122
123 if (fstat(fd, &st) < 0) {
124 perror(filename);
125 exit(1);
126 }
127
128 buf = NOFAIL(malloc(st.st_size + 1));
129
130 nbytes = st.st_size;
131
132 while (nbytes) {
133 ssize_t bytes_read;
134
135 bytes_read = read(fd, buf, nbytes);
136 if (bytes_read < 0) {
137 perror(filename);
138 exit(1);
139 }
140
141 nbytes -= bytes_read;
142 }
143 buf[st.st_size] = '\0';
144
145 close(fd);
146
147 return buf;
148 }
149
get_line(char ** stringp)150 char *get_line(char **stringp)
151 {
152 char *orig = *stringp, *next;
153
154 /* do not return the unwanted extra line at EOF */
155 if (!orig || *orig == '\0')
156 return NULL;
157
158 /* don't use strsep here, it is not available everywhere */
159 next = strchr(orig, '\n');
160 if (next)
161 *next++ = '\0';
162
163 *stringp = next;
164
165 return orig;
166 }
167
168 /* A list of all modules we processed */
169 LIST_HEAD(modules);
170
find_module(const char * modname)171 static struct module *find_module(const char *modname)
172 {
173 struct module *mod;
174
175 list_for_each_entry(mod, &modules, list) {
176 if (strcmp(mod->name, modname) == 0)
177 return mod;
178 }
179 return NULL;
180 }
181
new_module(const char * name,size_t namelen)182 static struct module *new_module(const char *name, size_t namelen)
183 {
184 struct module *mod;
185
186 mod = NOFAIL(malloc(sizeof(*mod) + namelen + 1));
187 memset(mod, 0, sizeof(*mod));
188
189 INIT_LIST_HEAD(&mod->exported_symbols);
190 INIT_LIST_HEAD(&mod->unresolved_symbols);
191 INIT_LIST_HEAD(&mod->missing_namespaces);
192 INIT_LIST_HEAD(&mod->imported_namespaces);
193
194 memcpy(mod->name, name, namelen);
195 mod->name[namelen] = '\0';
196 mod->is_vmlinux = (strcmp(mod->name, "vmlinux") == 0);
197
198 /*
199 * Set mod->is_gpl_compatible to true by default. If MODULE_LICENSE()
200 * is missing, do not check the use for EXPORT_SYMBOL_GPL() becasue
201 * modpost will exit wiht error anyway.
202 */
203 mod->is_gpl_compatible = true;
204
205 list_add_tail(&mod->list, &modules);
206
207 return mod;
208 }
209
210 /* A hash of all exported symbols,
211 * struct symbol is also used for lists of unresolved symbols */
212
213 #define SYMBOL_HASH_SIZE 1024
214
215 struct symbol {
216 struct symbol *next;
217 struct list_head list; /* link to module::exported_symbols or module::unresolved_symbols */
218 struct module *module;
219 char *namespace;
220 unsigned int crc;
221 bool crc_valid;
222 bool weak;
223 bool is_func;
224 bool is_gpl_only; /* exported by EXPORT_SYMBOL_GPL */
225 bool used; /* there exists a user of this symbol */
226 char name[];
227 };
228
229 static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
230
231 /* This is based on the hash algorithm from gdbm, via tdb */
tdb_hash(const char * name)232 static inline unsigned int tdb_hash(const char *name)
233 {
234 unsigned value; /* Used to compute the hash value. */
235 unsigned i; /* Used to cycle through random values. */
236
237 /* Set the initial value from the key size. */
238 for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
239 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
240
241 return (1103515243 * value + 12345);
242 }
243
244 /**
245 * Allocate a new symbols for use in the hash of exported symbols or
246 * the list of unresolved symbols per module
247 **/
alloc_symbol(const char * name)248 static struct symbol *alloc_symbol(const char *name)
249 {
250 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
251
252 memset(s, 0, sizeof(*s));
253 strcpy(s->name, name);
254
255 return s;
256 }
257
258 /* For the hash of exported symbols */
hash_add_symbol(struct symbol * sym)259 static void hash_add_symbol(struct symbol *sym)
260 {
261 unsigned int hash;
262
263 hash = tdb_hash(sym->name) % SYMBOL_HASH_SIZE;
264 sym->next = symbolhash[hash];
265 symbolhash[hash] = sym;
266 }
267
sym_add_unresolved(const char * name,struct module * mod,bool weak)268 static void sym_add_unresolved(const char *name, struct module *mod, bool weak)
269 {
270 struct symbol *sym;
271
272 sym = alloc_symbol(name);
273 sym->weak = weak;
274
275 list_add_tail(&sym->list, &mod->unresolved_symbols);
276 }
277
sym_find_with_module(const char * name,struct module * mod)278 static struct symbol *sym_find_with_module(const char *name, struct module *mod)
279 {
280 struct symbol *s;
281
282 /* For our purposes, .foo matches foo. PPC64 needs this. */
283 if (name[0] == '.')
284 name++;
285
286 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
287 if (strcmp(s->name, name) == 0 && (!mod || s->module == mod))
288 return s;
289 }
290 return NULL;
291 }
292
find_symbol(const char * name)293 static struct symbol *find_symbol(const char *name)
294 {
295 return sym_find_with_module(name, NULL);
296 }
297
298 struct namespace_list {
299 struct list_head list;
300 char namespace[];
301 };
302
contains_namespace(struct list_head * head,const char * namespace)303 static bool contains_namespace(struct list_head *head, const char *namespace)
304 {
305 struct namespace_list *list;
306
307 /*
308 * The default namespace is null string "", which is always implicitly
309 * contained.
310 */
311 if (!namespace[0])
312 return true;
313
314 list_for_each_entry(list, head, list) {
315 if (!strcmp(list->namespace, namespace))
316 return true;
317 }
318
319 return false;
320 }
321
add_namespace(struct list_head * head,const char * namespace)322 static void add_namespace(struct list_head *head, const char *namespace)
323 {
324 struct namespace_list *ns_entry;
325
326 if (!contains_namespace(head, namespace)) {
327 ns_entry = NOFAIL(malloc(sizeof(*ns_entry) +
328 strlen(namespace) + 1));
329 strcpy(ns_entry->namespace, namespace);
330 list_add_tail(&ns_entry->list, head);
331 }
332 }
333
sym_get_data_by_offset(const struct elf_info * info,unsigned int secindex,unsigned long offset)334 static void *sym_get_data_by_offset(const struct elf_info *info,
335 unsigned int secindex, unsigned long offset)
336 {
337 Elf_Shdr *sechdr = &info->sechdrs[secindex];
338
339 return (void *)info->hdr + sechdr->sh_offset + offset;
340 }
341
sym_get_data(const struct elf_info * info,const Elf_Sym * sym)342 void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym)
343 {
344 return sym_get_data_by_offset(info, get_secindex(info, sym),
345 sym->st_value);
346 }
347
sech_name(const struct elf_info * info,Elf_Shdr * sechdr)348 static const char *sech_name(const struct elf_info *info, Elf_Shdr *sechdr)
349 {
350 return sym_get_data_by_offset(info, info->secindex_strings,
351 sechdr->sh_name);
352 }
353
sec_name(const struct elf_info * info,unsigned int secindex)354 static const char *sec_name(const struct elf_info *info, unsigned int secindex)
355 {
356 /*
357 * If sym->st_shndx is a special section index, there is no
358 * corresponding section header.
359 * Return "" if the index is out of range of info->sechdrs[] array.
360 */
361 if (secindex >= info->num_sections)
362 return "";
363
364 return sech_name(info, &info->sechdrs[secindex]);
365 }
366
367 #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)
368
sym_add_exported(const char * name,struct module * mod,bool gpl_only,const char * namespace)369 static struct symbol *sym_add_exported(const char *name, struct module *mod,
370 bool gpl_only, const char *namespace)
371 {
372 struct symbol *s = find_symbol(name);
373
374 if (s && (!external_module || s->module->is_vmlinux || s->module == mod)) {
375 error("%s: '%s' exported twice. Previous export was in %s%s\n",
376 mod->name, name, s->module->name,
377 s->module->is_vmlinux ? "" : ".ko");
378 }
379
380 s = alloc_symbol(name);
381 s->module = mod;
382 s->is_gpl_only = gpl_only;
383 s->namespace = NOFAIL(strdup(namespace));
384 list_add_tail(&s->list, &mod->exported_symbols);
385 hash_add_symbol(s);
386
387 return s;
388 }
389
sym_set_crc(struct symbol * sym,unsigned int crc)390 static void sym_set_crc(struct symbol *sym, unsigned int crc)
391 {
392 sym->crc = crc;
393 sym->crc_valid = true;
394 }
395
grab_file(const char * filename,size_t * size)396 static void *grab_file(const char *filename, size_t *size)
397 {
398 struct stat st;
399 void *map = MAP_FAILED;
400 int fd;
401
402 fd = open(filename, O_RDONLY);
403 if (fd < 0)
404 return NULL;
405 if (fstat(fd, &st))
406 goto failed;
407
408 *size = st.st_size;
409 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
410
411 failed:
412 close(fd);
413 if (map == MAP_FAILED)
414 return NULL;
415 return map;
416 }
417
release_file(void * file,size_t size)418 static void release_file(void *file, size_t size)
419 {
420 munmap(file, size);
421 }
422
parse_elf(struct elf_info * info,const char * filename)423 static int parse_elf(struct elf_info *info, const char *filename)
424 {
425 unsigned int i;
426 Elf_Ehdr *hdr;
427 Elf_Shdr *sechdrs;
428 Elf_Sym *sym;
429 const char *secstrings;
430 unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
431
432 hdr = grab_file(filename, &info->size);
433 if (!hdr) {
434 if (ignore_missing_files) {
435 fprintf(stderr, "%s: %s (ignored)\n", filename,
436 strerror(errno));
437 return 0;
438 }
439 perror(filename);
440 exit(1);
441 }
442 info->hdr = hdr;
443 if (info->size < sizeof(*hdr)) {
444 /* file too small, assume this is an empty .o file */
445 return 0;
446 }
447 /* Is this a valid ELF file? */
448 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
449 (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
450 (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
451 (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
452 /* Not an ELF file - silently ignore it */
453 return 0;
454 }
455 /* Fix endianness in ELF header */
456 hdr->e_type = TO_NATIVE(hdr->e_type);
457 hdr->e_machine = TO_NATIVE(hdr->e_machine);
458 hdr->e_version = TO_NATIVE(hdr->e_version);
459 hdr->e_entry = TO_NATIVE(hdr->e_entry);
460 hdr->e_phoff = TO_NATIVE(hdr->e_phoff);
461 hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
462 hdr->e_flags = TO_NATIVE(hdr->e_flags);
463 hdr->e_ehsize = TO_NATIVE(hdr->e_ehsize);
464 hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
465 hdr->e_phnum = TO_NATIVE(hdr->e_phnum);
466 hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
467 hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
468 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
469 sechdrs = (void *)hdr + hdr->e_shoff;
470 info->sechdrs = sechdrs;
471
472 /* modpost only works for relocatable objects */
473 if (hdr->e_type != ET_REL)
474 fatal("%s: not relocatable object.", filename);
475
476 /* Check if file offset is correct */
477 if (hdr->e_shoff > info->size) {
478 fatal("section header offset=%lu in file '%s' is bigger than filesize=%zu\n",
479 (unsigned long)hdr->e_shoff, filename, info->size);
480 return 0;
481 }
482
483 if (hdr->e_shnum == SHN_UNDEF) {
484 /*
485 * There are more than 64k sections,
486 * read count from .sh_size.
487 */
488 info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
489 }
490 else {
491 info->num_sections = hdr->e_shnum;
492 }
493 if (hdr->e_shstrndx == SHN_XINDEX) {
494 info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
495 }
496 else {
497 info->secindex_strings = hdr->e_shstrndx;
498 }
499
500 /* Fix endianness in section headers */
501 for (i = 0; i < info->num_sections; i++) {
502 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
503 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
504 sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags);
505 sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr);
506 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
507 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
508 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
509 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info);
510 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
511 sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize);
512 }
513 /* Find symbol table. */
514 secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
515 for (i = 1; i < info->num_sections; i++) {
516 const char *secname;
517 int nobits = sechdrs[i].sh_type == SHT_NOBITS;
518
519 if (!nobits && sechdrs[i].sh_offset > info->size) {
520 fatal("%s is truncated. sechdrs[i].sh_offset=%lu > sizeof(*hrd)=%zu\n",
521 filename, (unsigned long)sechdrs[i].sh_offset,
522 sizeof(*hdr));
523 return 0;
524 }
525 secname = secstrings + sechdrs[i].sh_name;
526 if (strcmp(secname, ".modinfo") == 0) {
527 if (nobits)
528 fatal("%s has NOBITS .modinfo\n", filename);
529 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
530 info->modinfo_len = sechdrs[i].sh_size;
531 } else if (!strcmp(secname, ".export_symbol")) {
532 info->export_symbol_secndx = i;
533 }
534
535 if (sechdrs[i].sh_type == SHT_SYMTAB) {
536 unsigned int sh_link_idx;
537 symtab_idx = i;
538 info->symtab_start = (void *)hdr +
539 sechdrs[i].sh_offset;
540 info->symtab_stop = (void *)hdr +
541 sechdrs[i].sh_offset + sechdrs[i].sh_size;
542 sh_link_idx = sechdrs[i].sh_link;
543 info->strtab = (void *)hdr +
544 sechdrs[sh_link_idx].sh_offset;
545 }
546
547 /* 32bit section no. table? ("more than 64k sections") */
548 if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
549 symtab_shndx_idx = i;
550 info->symtab_shndx_start = (void *)hdr +
551 sechdrs[i].sh_offset;
552 info->symtab_shndx_stop = (void *)hdr +
553 sechdrs[i].sh_offset + sechdrs[i].sh_size;
554 }
555 }
556 if (!info->symtab_start)
557 fatal("%s has no symtab?\n", filename);
558
559 /* Fix endianness in symbols */
560 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
561 sym->st_shndx = TO_NATIVE(sym->st_shndx);
562 sym->st_name = TO_NATIVE(sym->st_name);
563 sym->st_value = TO_NATIVE(sym->st_value);
564 sym->st_size = TO_NATIVE(sym->st_size);
565 }
566
567 if (symtab_shndx_idx != ~0U) {
568 Elf32_Word *p;
569 if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
570 fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
571 filename, sechdrs[symtab_shndx_idx].sh_link,
572 symtab_idx);
573 /* Fix endianness */
574 for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
575 p++)
576 *p = TO_NATIVE(*p);
577 }
578
579 symsearch_init(info);
580
581 return 1;
582 }
583
parse_elf_finish(struct elf_info * info)584 static void parse_elf_finish(struct elf_info *info)
585 {
586 symsearch_finish(info);
587 release_file(info->hdr, info->size);
588 }
589
ignore_undef_symbol(struct elf_info * info,const char * symname)590 static int ignore_undef_symbol(struct elf_info *info, const char *symname)
591 {
592 /* ignore __this_module, it will be resolved shortly */
593 if (strcmp(symname, "__this_module") == 0)
594 return 1;
595 /* ignore global offset table */
596 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
597 return 1;
598 if (info->hdr->e_machine == EM_PPC)
599 /* Special register function linked on all modules during final link of .ko */
600 if (strstarts(symname, "_restgpr_") ||
601 strstarts(symname, "_savegpr_") ||
602 strstarts(symname, "_rest32gpr_") ||
603 strstarts(symname, "_save32gpr_") ||
604 strstarts(symname, "_restvr_") ||
605 strstarts(symname, "_savevr_"))
606 return 1;
607 if (info->hdr->e_machine == EM_PPC64)
608 /* Special register function linked on all modules during final link of .ko */
609 if (strstarts(symname, "_restgpr0_") ||
610 strstarts(symname, "_savegpr0_") ||
611 strstarts(symname, "_restvr_") ||
612 strstarts(symname, "_savevr_") ||
613 strcmp(symname, ".TOC.") == 0)
614 return 1;
615
616 if (info->hdr->e_machine == EM_S390)
617 /* Expoline thunks are linked on all kernel modules during final link of .ko */
618 if (strstarts(symname, "__s390_indirect_jump_r"))
619 return 1;
620 /* Do not ignore this symbol */
621 return 0;
622 }
623
handle_symbol(struct module * mod,struct elf_info * info,const Elf_Sym * sym,const char * symname)624 static void handle_symbol(struct module *mod, struct elf_info *info,
625 const Elf_Sym *sym, const char *symname)
626 {
627 switch (sym->st_shndx) {
628 case SHN_COMMON:
629 if (strstarts(symname, "__gnu_lto_")) {
630 /* Should warn here, but modpost runs before the linker */
631 } else
632 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
633 break;
634 case SHN_UNDEF:
635 /* undefined symbol */
636 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
637 ELF_ST_BIND(sym->st_info) != STB_WEAK)
638 break;
639 if (ignore_undef_symbol(info, symname))
640 break;
641 if (info->hdr->e_machine == EM_SPARC ||
642 info->hdr->e_machine == EM_SPARCV9) {
643 /* Ignore register directives. */
644 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
645 break;
646 if (symname[0] == '.') {
647 char *munged = NOFAIL(strdup(symname));
648 munged[0] = '_';
649 munged[1] = toupper(munged[1]);
650 symname = munged;
651 }
652 }
653
654 sym_add_unresolved(symname, mod,
655 ELF_ST_BIND(sym->st_info) == STB_WEAK);
656 break;
657 default:
658 if (strcmp(symname, "init_module") == 0)
659 mod->has_init = true;
660 if (strcmp(symname, "cleanup_module") == 0)
661 mod->has_cleanup = true;
662 break;
663 }
664 }
665
666 /**
667 * Parse tag=value strings from .modinfo section
668 **/
next_string(char * string,unsigned long * secsize)669 static char *next_string(char *string, unsigned long *secsize)
670 {
671 /* Skip non-zero chars */
672 while (string[0]) {
673 string++;
674 if ((*secsize)-- <= 1)
675 return NULL;
676 }
677
678 /* Skip any zero padding. */
679 while (!string[0]) {
680 string++;
681 if ((*secsize)-- <= 1)
682 return NULL;
683 }
684 return string;
685 }
686
get_next_modinfo(struct elf_info * info,const char * tag,char * prev)687 static char *get_next_modinfo(struct elf_info *info, const char *tag,
688 char *prev)
689 {
690 char *p;
691 unsigned int taglen = strlen(tag);
692 char *modinfo = info->modinfo;
693 unsigned long size = info->modinfo_len;
694
695 if (prev) {
696 size -= prev - modinfo;
697 modinfo = next_string(prev, &size);
698 }
699
700 for (p = modinfo; p; p = next_string(p, &size)) {
701 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
702 return p + taglen + 1;
703 }
704 return NULL;
705 }
706
get_modinfo(struct elf_info * info,const char * tag)707 static char *get_modinfo(struct elf_info *info, const char *tag)
708
709 {
710 return get_next_modinfo(info, tag, NULL);
711 }
712
sym_name(struct elf_info * elf,Elf_Sym * sym)713 static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
714 {
715 if (sym)
716 return elf->strtab + sym->st_name;
717 else
718 return "(unknown)";
719 }
720
721 /*
722 * Check whether the 'string' argument matches one of the 'patterns',
723 * an array of shell wildcard patterns (glob).
724 *
725 * Return true is there is a match.
726 */
match(const char * string,const char * const patterns[])727 static bool match(const char *string, const char *const patterns[])
728 {
729 const char *pattern;
730
731 while ((pattern = *patterns++)) {
732 if (!fnmatch(pattern, string, 0))
733 return true;
734 }
735
736 return false;
737 }
738
739 /* useful to pass patterns to match() directly */
740 #define PATTERNS(...) \
741 ({ \
742 static const char *const patterns[] = {__VA_ARGS__, NULL}; \
743 patterns; \
744 })
745
746 /* sections that we do not want to do full section mismatch check on */
747 static const char *const section_white_list[] =
748 {
749 ".comment*",
750 ".debug*",
751 ".zdebug*", /* Compressed debug sections. */
752 ".GCC.command.line", /* record-gcc-switches */
753 ".mdebug*", /* alpha, score, mips etc. */
754 ".pdr", /* alpha, score, mips etc. */
755 ".stab*",
756 ".note*",
757 ".got*",
758 ".toc*",
759 ".xt.prop", /* xtensa */
760 ".xt.lit", /* xtensa */
761 ".arcextmap*", /* arc */
762 ".gnu.linkonce.arcext*", /* arc : modules */
763 ".cmem*", /* EZchip */
764 ".fmt_slot*", /* EZchip */
765 ".gnu.lto*",
766 ".discard.*",
767 ".llvm.call-graph-profile", /* call graph */
768 NULL
769 };
770
771 /*
772 * This is used to find sections missing the SHF_ALLOC flag.
773 * The cause of this is often a section specified in assembler
774 * without "ax" / "aw".
775 */
check_section(const char * modname,struct elf_info * elf,Elf_Shdr * sechdr)776 static void check_section(const char *modname, struct elf_info *elf,
777 Elf_Shdr *sechdr)
778 {
779 const char *sec = sech_name(elf, sechdr);
780
781 if (sechdr->sh_type == SHT_PROGBITS &&
782 !(sechdr->sh_flags & SHF_ALLOC) &&
783 !match(sec, section_white_list)) {
784 warn("%s (%s): unexpected non-allocatable section.\n"
785 "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
786 "Note that for example <linux/init.h> contains\n"
787 "section definitions for use in .S files.\n\n",
788 modname, sec);
789 }
790 }
791
792
793
794 #define ALL_INIT_DATA_SECTIONS \
795 ".init.setup", ".init.rodata", ".meminit.rodata", \
796 ".init.data", ".meminit.data"
797 #define ALL_EXIT_DATA_SECTIONS \
798 ".exit.data", ".memexit.data"
799
800 #define ALL_INIT_TEXT_SECTIONS \
801 ".init.text", ".meminit.text"
802 #define ALL_EXIT_TEXT_SECTIONS \
803 ".exit.text"
804
805 #define ALL_PCI_INIT_SECTIONS \
806 ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
807 ".pci_fixup_enable", ".pci_fixup_resume", \
808 ".pci_fixup_resume_early", ".pci_fixup_suspend"
809
810 #define ALL_XXXINIT_SECTIONS MEM_INIT_SECTIONS
811
812 #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
813 #define ALL_EXIT_SECTIONS EXIT_SECTIONS
814
815 #define DATA_SECTIONS ".data", ".data.rel"
816 #define TEXT_SECTIONS ".text", ".text.*", ".sched.text", \
817 ".kprobes.text", ".cpuidle.text", ".noinstr.text", \
818 ".ltext", ".ltext.*"
819 #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
820 ".fixup", ".entry.text", ".exception.text", \
821 ".coldtext", ".softirqentry.text"
822
823 #define INIT_SECTIONS ".init.*"
824 #define MEM_INIT_SECTIONS ".meminit.*"
825
826 #define EXIT_SECTIONS ".exit.*"
827
828 #define ALL_TEXT_SECTIONS ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \
829 TEXT_SECTIONS, OTHER_TEXT_SECTIONS
830
831 enum mismatch {
832 TEXT_TO_ANY_INIT,
833 DATA_TO_ANY_INIT,
834 TEXTDATA_TO_ANY_EXIT,
835 XXXINIT_TO_SOME_INIT,
836 ANY_INIT_TO_ANY_EXIT,
837 ANY_EXIT_TO_ANY_INIT,
838 EXTABLE_TO_NON_TEXT,
839 };
840
841 /**
842 * Describe how to match sections on different criteria:
843 *
844 * @fromsec: Array of sections to be matched.
845 *
846 * @bad_tosec: Relocations applied to a section in @fromsec to a section in
847 * this array is forbidden (black-list). Can be empty.
848 *
849 * @good_tosec: Relocations applied to a section in @fromsec must be
850 * targeting sections in this array (white-list). Can be empty.
851 *
852 * @mismatch: Type of mismatch.
853 */
854 struct sectioncheck {
855 const char *fromsec[20];
856 const char *bad_tosec[20];
857 const char *good_tosec[20];
858 enum mismatch mismatch;
859 };
860
861 static const struct sectioncheck sectioncheck[] = {
862 /* Do not reference init/exit code/data from
863 * normal code and data
864 */
865 {
866 .fromsec = { TEXT_SECTIONS, NULL },
867 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
868 .mismatch = TEXT_TO_ANY_INIT,
869 },
870 {
871 .fromsec = { DATA_SECTIONS, NULL },
872 .bad_tosec = { ALL_XXXINIT_SECTIONS, INIT_SECTIONS, NULL },
873 .mismatch = DATA_TO_ANY_INIT,
874 },
875 {
876 .fromsec = { TEXT_SECTIONS, DATA_SECTIONS, NULL },
877 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
878 .mismatch = TEXTDATA_TO_ANY_EXIT,
879 },
880 /* Do not reference init code/data from meminit code/data */
881 {
882 .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
883 .bad_tosec = { INIT_SECTIONS, NULL },
884 .mismatch = XXXINIT_TO_SOME_INIT,
885 },
886 /* Do not use exit code/data from init code */
887 {
888 .fromsec = { ALL_INIT_SECTIONS, NULL },
889 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
890 .mismatch = ANY_INIT_TO_ANY_EXIT,
891 },
892 /* Do not use init code/data from exit code */
893 {
894 .fromsec = { ALL_EXIT_SECTIONS, NULL },
895 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
896 .mismatch = ANY_EXIT_TO_ANY_INIT,
897 },
898 {
899 .fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
900 .bad_tosec = { INIT_SECTIONS, NULL },
901 .mismatch = ANY_INIT_TO_ANY_EXIT,
902 },
903 {
904 .fromsec = { "__ex_table", NULL },
905 /* If you're adding any new black-listed sections in here, consider
906 * adding a special 'printer' for them in scripts/check_extable.
907 */
908 .bad_tosec = { ".altinstr_replacement", NULL },
909 .good_tosec = {ALL_TEXT_SECTIONS , NULL},
910 .mismatch = EXTABLE_TO_NON_TEXT,
911 }
912 };
913
section_mismatch(const char * fromsec,const char * tosec)914 static const struct sectioncheck *section_mismatch(
915 const char *fromsec, const char *tosec)
916 {
917 int i;
918
919 /*
920 * The target section could be the SHT_NUL section when we're
921 * handling relocations to un-resolved symbols, trying to match it
922 * doesn't make much sense and causes build failures on parisc
923 * architectures.
924 */
925 if (*tosec == '\0')
926 return NULL;
927
928 for (i = 0; i < ARRAY_SIZE(sectioncheck); i++) {
929 const struct sectioncheck *check = §ioncheck[i];
930
931 if (match(fromsec, check->fromsec)) {
932 if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
933 return check;
934 if (check->good_tosec[0] && !match(tosec, check->good_tosec))
935 return check;
936 }
937 }
938 return NULL;
939 }
940
941 /**
942 * Whitelist to allow certain references to pass with no warning.
943 *
944 * Pattern 1:
945 * If a module parameter is declared __initdata and permissions=0
946 * then this is legal despite the warning generated.
947 * We cannot see value of permissions here, so just ignore
948 * this pattern.
949 * The pattern is identified by:
950 * tosec = .init.data
951 * fromsec = .data*
952 * atsym =__param*
953 *
954 * Pattern 1a:
955 * module_param_call() ops can refer to __init set function if permissions=0
956 * The pattern is identified by:
957 * tosec = .init.text
958 * fromsec = .data*
959 * atsym = __param_ops_*
960 *
961 * Pattern 3:
962 * Whitelist all references from .head.text to any init section
963 *
964 * Pattern 4:
965 * Some symbols belong to init section but still it is ok to reference
966 * these from non-init sections as these symbols don't have any memory
967 * allocated for them and symbol address and value are same. So even
968 * if init section is freed, its ok to reference those symbols.
969 * For ex. symbols marking the init section boundaries.
970 * This pattern is identified by
971 * refsymname = __init_begin, _sinittext, _einittext
972 *
973 * Pattern 5:
974 * GCC may optimize static inlines when fed constant arg(s) resulting
975 * in functions like cpumask_empty() -- generating an associated symbol
976 * cpumask_empty.constprop.3 that appears in the audit. If the const that
977 * is passed in comes from __init, like say nmi_ipi_mask, we get a
978 * meaningless section warning. May need to add isra symbols too...
979 * This pattern is identified by
980 * tosec = init section
981 * fromsec = text section
982 * refsymname = *.constprop.*
983 *
984 **/
secref_whitelist(const char * fromsec,const char * fromsym,const char * tosec,const char * tosym)985 static int secref_whitelist(const char *fromsec, const char *fromsym,
986 const char *tosec, const char *tosym)
987 {
988 /* Check for pattern 1 */
989 if (match(tosec, PATTERNS(ALL_INIT_DATA_SECTIONS)) &&
990 match(fromsec, PATTERNS(DATA_SECTIONS)) &&
991 strstarts(fromsym, "__param"))
992 return 0;
993
994 /* Check for pattern 1a */
995 if (strcmp(tosec, ".init.text") == 0 &&
996 match(fromsec, PATTERNS(DATA_SECTIONS)) &&
997 strstarts(fromsym, "__param_ops_"))
998 return 0;
999
1000 /* symbols in data sections that may refer to any init/exit sections */
1001 if (match(fromsec, PATTERNS(DATA_SECTIONS)) &&
1002 match(tosec, PATTERNS(ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS)) &&
1003 match(fromsym, PATTERNS("*_template", // scsi uses *_template a lot
1004 "*_timer", // arm uses ops structures named _timer a lot
1005 "*_sht", // scsi also used *_sht to some extent
1006 "*_ops",
1007 "*_probe",
1008 "*_probe_one",
1009 "*_console")))
1010 return 0;
1011
1012 /* symbols in data sections that may refer to meminit sections */
1013 if (match(fromsec, PATTERNS(DATA_SECTIONS)) &&
1014 match(tosec, PATTERNS(ALL_XXXINIT_SECTIONS)) &&
1015 match(fromsym, PATTERNS("*driver")))
1016 return 0;
1017
1018 /*
1019 * symbols in data sections must not refer to .exit.*, but there are
1020 * quite a few offenders, so hide these unless for W=1 builds until
1021 * these are fixed.
1022 */
1023 if (!extra_warn &&
1024 match(fromsec, PATTERNS(DATA_SECTIONS)) &&
1025 match(tosec, PATTERNS(EXIT_SECTIONS)) &&
1026 match(fromsym, PATTERNS("*driver")))
1027 return 0;
1028
1029 /* Check for pattern 3 */
1030 if (strstarts(fromsec, ".head.text") &&
1031 match(tosec, PATTERNS(ALL_INIT_SECTIONS)))
1032 return 0;
1033
1034 /* Check for pattern 4 */
1035 if (match(tosym, PATTERNS("__init_begin", "_sinittext", "_einittext")))
1036 return 0;
1037
1038 /* Check for pattern 5 */
1039 if (match(fromsec, PATTERNS(ALL_TEXT_SECTIONS)) &&
1040 match(tosec, PATTERNS(ALL_INIT_SECTIONS)) &&
1041 match(fromsym, PATTERNS("*.constprop.*")))
1042 return 0;
1043
1044 return 1;
1045 }
1046
find_fromsym(struct elf_info * elf,Elf_Addr addr,unsigned int secndx)1047 static Elf_Sym *find_fromsym(struct elf_info *elf, Elf_Addr addr,
1048 unsigned int secndx)
1049 {
1050 return symsearch_find_nearest(elf, addr, secndx, false, ~0);
1051 }
1052
find_tosym(struct elf_info * elf,Elf_Addr addr,Elf_Sym * sym)1053 static Elf_Sym *find_tosym(struct elf_info *elf, Elf_Addr addr, Elf_Sym *sym)
1054 {
1055 Elf_Sym *new_sym;
1056
1057 /* If the supplied symbol has a valid name, return it */
1058 if (is_valid_name(elf, sym))
1059 return sym;
1060
1061 /*
1062 * Strive to find a better symbol name, but the resulting name may not
1063 * match the symbol referenced in the original code.
1064 */
1065 new_sym = symsearch_find_nearest(elf, addr, get_secindex(elf, sym),
1066 true, 20);
1067 return new_sym ? new_sym : sym;
1068 }
1069
is_executable_section(struct elf_info * elf,unsigned int secndx)1070 static bool is_executable_section(struct elf_info *elf, unsigned int secndx)
1071 {
1072 if (secndx >= elf->num_sections)
1073 return false;
1074
1075 return (elf->sechdrs[secndx].sh_flags & SHF_EXECINSTR) != 0;
1076 }
1077
default_mismatch_handler(const char * modname,struct elf_info * elf,const struct sectioncheck * const mismatch,Elf_Sym * tsym,unsigned int fsecndx,const char * fromsec,Elf_Addr faddr,const char * tosec,Elf_Addr taddr)1078 static void default_mismatch_handler(const char *modname, struct elf_info *elf,
1079 const struct sectioncheck* const mismatch,
1080 Elf_Sym *tsym,
1081 unsigned int fsecndx, const char *fromsec, Elf_Addr faddr,
1082 const char *tosec, Elf_Addr taddr)
1083 {
1084 Elf_Sym *from;
1085 const char *tosym;
1086 const char *fromsym;
1087
1088 from = find_fromsym(elf, faddr, fsecndx);
1089 fromsym = sym_name(elf, from);
1090
1091 tsym = find_tosym(elf, taddr, tsym);
1092 tosym = sym_name(elf, tsym);
1093
1094 /* check whitelist - we may ignore it */
1095 if (!secref_whitelist(fromsec, fromsym, tosec, tosym))
1096 return;
1097
1098 sec_mismatch_count++;
1099
1100 warn("%s: section mismatch in reference: %s+0x%x (section: %s) -> %s (section: %s)\n",
1101 modname, fromsym,
1102 (unsigned int)(faddr - (from ? from->st_value : 0)),
1103 fromsec, tosym, tosec);
1104
1105 if (mismatch->mismatch == EXTABLE_TO_NON_TEXT) {
1106 if (match(tosec, mismatch->bad_tosec))
1107 fatal("The relocation at %s+0x%lx references\n"
1108 "section \"%s\" which is black-listed.\n"
1109 "Something is seriously wrong and should be fixed.\n"
1110 "You might get more information about where this is\n"
1111 "coming from by using scripts/check_extable.sh %s\n",
1112 fromsec, (long)faddr, tosec, modname);
1113 else if (is_executable_section(elf, get_secindex(elf, tsym)))
1114 warn("The relocation at %s+0x%lx references\n"
1115 "section \"%s\" which is not in the list of\n"
1116 "authorized sections. If you're adding a new section\n"
1117 "and/or if this reference is valid, add \"%s\" to the\n"
1118 "list of authorized sections to jump to on fault.\n"
1119 "This can be achieved by adding \"%s\" to\n"
1120 "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
1121 fromsec, (long)faddr, tosec, tosec, tosec);
1122 else
1123 error("%s+0x%lx references non-executable section '%s'\n",
1124 fromsec, (long)faddr, tosec);
1125 }
1126 }
1127
check_export_symbol(struct module * mod,struct elf_info * elf,Elf_Addr faddr,const char * secname,Elf_Sym * sym)1128 static void check_export_symbol(struct module *mod, struct elf_info *elf,
1129 Elf_Addr faddr, const char *secname,
1130 Elf_Sym *sym)
1131 {
1132 static const char *prefix = "__export_symbol_";
1133 const char *label_name, *name, *data;
1134 Elf_Sym *label;
1135 struct symbol *s;
1136 bool is_gpl;
1137
1138 label = find_fromsym(elf, faddr, elf->export_symbol_secndx);
1139 label_name = sym_name(elf, label);
1140
1141 if (!strstarts(label_name, prefix)) {
1142 error("%s: .export_symbol section contains strange symbol '%s'\n",
1143 mod->name, label_name);
1144 return;
1145 }
1146
1147 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
1148 ELF_ST_BIND(sym->st_info) != STB_WEAK) {
1149 error("%s: local symbol '%s' was exported\n", mod->name,
1150 label_name + strlen(prefix));
1151 return;
1152 }
1153
1154 name = sym_name(elf, sym);
1155 if (strcmp(label_name + strlen(prefix), name)) {
1156 error("%s: .export_symbol section references '%s', but it does not seem to be an export symbol\n",
1157 mod->name, name);
1158 return;
1159 }
1160
1161 data = sym_get_data(elf, label); /* license */
1162 if (!strcmp(data, "GPL")) {
1163 is_gpl = true;
1164 } else if (!strcmp(data, "")) {
1165 is_gpl = false;
1166 } else {
1167 error("%s: unknown license '%s' was specified for '%s'\n",
1168 mod->name, data, name);
1169 return;
1170 }
1171
1172 data += strlen(data) + 1; /* namespace */
1173 s = sym_add_exported(name, mod, is_gpl, data);
1174
1175 /*
1176 * We need to be aware whether we are exporting a function or
1177 * a data on some architectures.
1178 */
1179 s->is_func = (ELF_ST_TYPE(sym->st_info) == STT_FUNC);
1180
1181 /*
1182 * For parisc64, symbols prefixed $$ from the library have the symbol type
1183 * STT_LOPROC. They should be handled as functions too.
1184 */
1185 if (elf->hdr->e_ident[EI_CLASS] == ELFCLASS64 &&
1186 elf->hdr->e_machine == EM_PARISC &&
1187 ELF_ST_TYPE(sym->st_info) == STT_LOPROC)
1188 s->is_func = true;
1189
1190 if (match(secname, PATTERNS(INIT_SECTIONS)))
1191 warn("%s: %s: EXPORT_SYMBOL used for init symbol. Remove __init or EXPORT_SYMBOL.\n",
1192 mod->name, name);
1193 else if (match(secname, PATTERNS(EXIT_SECTIONS)))
1194 warn("%s: %s: EXPORT_SYMBOL used for exit symbol. Remove __exit or EXPORT_SYMBOL.\n",
1195 mod->name, name);
1196 }
1197
check_section_mismatch(struct module * mod,struct elf_info * elf,Elf_Sym * sym,unsigned int fsecndx,const char * fromsec,Elf_Addr faddr,Elf_Addr taddr)1198 static void check_section_mismatch(struct module *mod, struct elf_info *elf,
1199 Elf_Sym *sym,
1200 unsigned int fsecndx, const char *fromsec,
1201 Elf_Addr faddr, Elf_Addr taddr)
1202 {
1203 const char *tosec = sec_name(elf, get_secindex(elf, sym));
1204 const struct sectioncheck *mismatch;
1205
1206 if (module_enabled && elf->export_symbol_secndx == fsecndx) {
1207 check_export_symbol(mod, elf, faddr, tosec, sym);
1208 return;
1209 }
1210
1211 mismatch = section_mismatch(fromsec, tosec);
1212 if (!mismatch)
1213 return;
1214
1215 default_mismatch_handler(mod->name, elf, mismatch, sym,
1216 fsecndx, fromsec, faddr,
1217 tosec, taddr);
1218 }
1219
addend_386_rel(uint32_t * location,unsigned int r_type)1220 static Elf_Addr addend_386_rel(uint32_t *location, unsigned int r_type)
1221 {
1222 switch (r_type) {
1223 case R_386_32:
1224 return TO_NATIVE(*location);
1225 case R_386_PC32:
1226 return TO_NATIVE(*location) + 4;
1227 }
1228
1229 return (Elf_Addr)(-1);
1230 }
1231
1232 #ifndef R_ARM_CALL
1233 #define R_ARM_CALL 28
1234 #endif
1235 #ifndef R_ARM_JUMP24
1236 #define R_ARM_JUMP24 29
1237 #endif
1238
1239 #ifndef R_ARM_THM_CALL
1240 #define R_ARM_THM_CALL 10
1241 #endif
1242 #ifndef R_ARM_THM_JUMP24
1243 #define R_ARM_THM_JUMP24 30
1244 #endif
1245
1246 #ifndef R_ARM_MOVW_ABS_NC
1247 #define R_ARM_MOVW_ABS_NC 43
1248 #endif
1249
1250 #ifndef R_ARM_MOVT_ABS
1251 #define R_ARM_MOVT_ABS 44
1252 #endif
1253
1254 #ifndef R_ARM_THM_MOVW_ABS_NC
1255 #define R_ARM_THM_MOVW_ABS_NC 47
1256 #endif
1257
1258 #ifndef R_ARM_THM_MOVT_ABS
1259 #define R_ARM_THM_MOVT_ABS 48
1260 #endif
1261
1262 #ifndef R_ARM_THM_JUMP19
1263 #define R_ARM_THM_JUMP19 51
1264 #endif
1265
sign_extend32(int32_t value,int index)1266 static int32_t sign_extend32(int32_t value, int index)
1267 {
1268 uint8_t shift = 31 - index;
1269
1270 return (int32_t)(value << shift) >> shift;
1271 }
1272
addend_arm_rel(void * loc,Elf_Sym * sym,unsigned int r_type)1273 static Elf_Addr addend_arm_rel(void *loc, Elf_Sym *sym, unsigned int r_type)
1274 {
1275 uint32_t inst, upper, lower, sign, j1, j2;
1276 int32_t offset;
1277
1278 switch (r_type) {
1279 case R_ARM_ABS32:
1280 case R_ARM_REL32:
1281 inst = TO_NATIVE(*(uint32_t *)loc);
1282 return inst + sym->st_value;
1283 case R_ARM_MOVW_ABS_NC:
1284 case R_ARM_MOVT_ABS:
1285 inst = TO_NATIVE(*(uint32_t *)loc);
1286 offset = sign_extend32(((inst & 0xf0000) >> 4) | (inst & 0xfff),
1287 15);
1288 return offset + sym->st_value;
1289 case R_ARM_PC24:
1290 case R_ARM_CALL:
1291 case R_ARM_JUMP24:
1292 inst = TO_NATIVE(*(uint32_t *)loc);
1293 offset = sign_extend32((inst & 0x00ffffff) << 2, 25);
1294 return offset + sym->st_value + 8;
1295 case R_ARM_THM_MOVW_ABS_NC:
1296 case R_ARM_THM_MOVT_ABS:
1297 upper = TO_NATIVE(*(uint16_t *)loc);
1298 lower = TO_NATIVE(*((uint16_t *)loc + 1));
1299 offset = sign_extend32(((upper & 0x000f) << 12) |
1300 ((upper & 0x0400) << 1) |
1301 ((lower & 0x7000) >> 4) |
1302 (lower & 0x00ff),
1303 15);
1304 return offset + sym->st_value;
1305 case R_ARM_THM_JUMP19:
1306 /*
1307 * Encoding T3:
1308 * S = upper[10]
1309 * imm6 = upper[5:0]
1310 * J1 = lower[13]
1311 * J2 = lower[11]
1312 * imm11 = lower[10:0]
1313 * imm32 = SignExtend(S:J2:J1:imm6:imm11:'0')
1314 */
1315 upper = TO_NATIVE(*(uint16_t *)loc);
1316 lower = TO_NATIVE(*((uint16_t *)loc + 1));
1317
1318 sign = (upper >> 10) & 1;
1319 j1 = (lower >> 13) & 1;
1320 j2 = (lower >> 11) & 1;
1321 offset = sign_extend32((sign << 20) | (j2 << 19) | (j1 << 18) |
1322 ((upper & 0x03f) << 12) |
1323 ((lower & 0x07ff) << 1),
1324 20);
1325 return offset + sym->st_value + 4;
1326 case R_ARM_THM_CALL:
1327 case R_ARM_THM_JUMP24:
1328 /*
1329 * Encoding T4:
1330 * S = upper[10]
1331 * imm10 = upper[9:0]
1332 * J1 = lower[13]
1333 * J2 = lower[11]
1334 * imm11 = lower[10:0]
1335 * I1 = NOT(J1 XOR S)
1336 * I2 = NOT(J2 XOR S)
1337 * imm32 = SignExtend(S:I1:I2:imm10:imm11:'0')
1338 */
1339 upper = TO_NATIVE(*(uint16_t *)loc);
1340 lower = TO_NATIVE(*((uint16_t *)loc + 1));
1341
1342 sign = (upper >> 10) & 1;
1343 j1 = (lower >> 13) & 1;
1344 j2 = (lower >> 11) & 1;
1345 offset = sign_extend32((sign << 24) |
1346 ((~(j1 ^ sign) & 1) << 23) |
1347 ((~(j2 ^ sign) & 1) << 22) |
1348 ((upper & 0x03ff) << 12) |
1349 ((lower & 0x07ff) << 1),
1350 24);
1351 return offset + sym->st_value + 4;
1352 }
1353
1354 return (Elf_Addr)(-1);
1355 }
1356
addend_mips_rel(uint32_t * location,unsigned int r_type)1357 static Elf_Addr addend_mips_rel(uint32_t *location, unsigned int r_type)
1358 {
1359 uint32_t inst;
1360
1361 inst = TO_NATIVE(*location);
1362 switch (r_type) {
1363 case R_MIPS_LO16:
1364 return inst & 0xffff;
1365 case R_MIPS_26:
1366 return (inst & 0x03ffffff) << 2;
1367 case R_MIPS_32:
1368 return inst;
1369 }
1370 return (Elf_Addr)(-1);
1371 }
1372
1373 #ifndef EM_RISCV
1374 #define EM_RISCV 243
1375 #endif
1376
1377 #ifndef R_RISCV_SUB32
1378 #define R_RISCV_SUB32 39
1379 #endif
1380
1381 #ifndef EM_LOONGARCH
1382 #define EM_LOONGARCH 258
1383 #endif
1384
1385 #ifndef R_LARCH_SUB32
1386 #define R_LARCH_SUB32 55
1387 #endif
1388
get_rel_type_and_sym(struct elf_info * elf,uint64_t r_info,unsigned int * r_type,unsigned int * r_sym)1389 static void get_rel_type_and_sym(struct elf_info *elf, uint64_t r_info,
1390 unsigned int *r_type, unsigned int *r_sym)
1391 {
1392 typedef struct {
1393 Elf64_Word r_sym; /* Symbol index */
1394 unsigned char r_ssym; /* Special symbol for 2nd relocation */
1395 unsigned char r_type3; /* 3rd relocation type */
1396 unsigned char r_type2; /* 2nd relocation type */
1397 unsigned char r_type; /* 1st relocation type */
1398 } Elf64_Mips_R_Info;
1399
1400 bool is_64bit = (elf->hdr->e_ident[EI_CLASS] == ELFCLASS64);
1401
1402 if (elf->hdr->e_machine == EM_MIPS && is_64bit) {
1403 Elf64_Mips_R_Info *mips64_r_info = (void *)&r_info;
1404
1405 *r_type = mips64_r_info->r_type;
1406 *r_sym = TO_NATIVE(mips64_r_info->r_sym);
1407 return;
1408 }
1409
1410 if (is_64bit) {
1411 Elf64_Xword r_info64 = r_info;
1412
1413 r_info = TO_NATIVE(r_info64);
1414 } else {
1415 Elf32_Word r_info32 = r_info;
1416
1417 r_info = TO_NATIVE(r_info32);
1418 }
1419
1420 *r_type = ELF_R_TYPE(r_info);
1421 *r_sym = ELF_R_SYM(r_info);
1422 }
1423
section_rela(struct module * mod,struct elf_info * elf,Elf_Shdr * sechdr)1424 static void section_rela(struct module *mod, struct elf_info *elf,
1425 Elf_Shdr *sechdr)
1426 {
1427 Elf_Rela *rela;
1428 unsigned int fsecndx = sechdr->sh_info;
1429 const char *fromsec = sec_name(elf, fsecndx);
1430 Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1431 Elf_Rela *stop = (void *)start + sechdr->sh_size;
1432
1433 /* if from section (name) is know good then skip it */
1434 if (match(fromsec, section_white_list))
1435 return;
1436
1437 for (rela = start; rela < stop; rela++) {
1438 Elf_Sym *tsym;
1439 Elf_Addr taddr, r_offset;
1440 unsigned int r_type, r_sym;
1441
1442 r_offset = TO_NATIVE(rela->r_offset);
1443 get_rel_type_and_sym(elf, rela->r_info, &r_type, &r_sym);
1444
1445 tsym = elf->symtab_start + r_sym;
1446 taddr = tsym->st_value + TO_NATIVE(rela->r_addend);
1447
1448 switch (elf->hdr->e_machine) {
1449 case EM_RISCV:
1450 if (!strcmp("__ex_table", fromsec) &&
1451 r_type == R_RISCV_SUB32)
1452 continue;
1453 break;
1454 case EM_LOONGARCH:
1455 if (!strcmp("__ex_table", fromsec) &&
1456 r_type == R_LARCH_SUB32)
1457 continue;
1458 break;
1459 }
1460
1461 check_section_mismatch(mod, elf, tsym,
1462 fsecndx, fromsec, r_offset, taddr);
1463 }
1464 }
1465
section_rel(struct module * mod,struct elf_info * elf,Elf_Shdr * sechdr)1466 static void section_rel(struct module *mod, struct elf_info *elf,
1467 Elf_Shdr *sechdr)
1468 {
1469 Elf_Rel *rel;
1470 unsigned int fsecndx = sechdr->sh_info;
1471 const char *fromsec = sec_name(elf, fsecndx);
1472 Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1473 Elf_Rel *stop = (void *)start + sechdr->sh_size;
1474
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 Elf_Sym *tsym;
1481 Elf_Addr taddr = 0, r_offset;
1482 unsigned int r_type, r_sym;
1483 void *loc;
1484
1485 r_offset = TO_NATIVE(rel->r_offset);
1486 get_rel_type_and_sym(elf, rel->r_info, &r_type, &r_sym);
1487
1488 loc = sym_get_data_by_offset(elf, fsecndx, r_offset);
1489 tsym = elf->symtab_start + r_sym;
1490
1491 switch (elf->hdr->e_machine) {
1492 case EM_386:
1493 taddr = addend_386_rel(loc, r_type);
1494 break;
1495 case EM_ARM:
1496 taddr = addend_arm_rel(loc, tsym, r_type);
1497 break;
1498 case EM_MIPS:
1499 taddr = addend_mips_rel(loc, r_type);
1500 break;
1501 default:
1502 fatal("Please add code to calculate addend for this architecture\n");
1503 }
1504
1505 check_section_mismatch(mod, elf, tsym,
1506 fsecndx, fromsec, r_offset, taddr);
1507 }
1508 }
1509
1510 /**
1511 * A module includes a number of sections that are discarded
1512 * either when loaded or when used as built-in.
1513 * For loaded modules all functions marked __init and all data
1514 * marked __initdata will be discarded when the module has been initialized.
1515 * Likewise for modules used built-in the sections marked __exit
1516 * are discarded because __exit marked function are supposed to be called
1517 * only when a module is unloaded which never happens for built-in modules.
1518 * The check_sec_ref() function traverses all relocation records
1519 * to find all references to a section that reference a section that will
1520 * be discarded and warns about it.
1521 **/
check_sec_ref(struct module * mod,struct elf_info * elf)1522 static void check_sec_ref(struct module *mod, struct elf_info *elf)
1523 {
1524 int i;
1525 Elf_Shdr *sechdrs = elf->sechdrs;
1526
1527 /* Walk through all sections */
1528 for (i = 0; i < elf->num_sections; i++) {
1529 check_section(mod->name, elf, &elf->sechdrs[i]);
1530 /* We want to process only relocation sections and not .init */
1531 if (sechdrs[i].sh_type == SHT_RELA)
1532 section_rela(mod, elf, &elf->sechdrs[i]);
1533 else if (sechdrs[i].sh_type == SHT_REL)
1534 section_rel(mod, elf, &elf->sechdrs[i]);
1535 }
1536 }
1537
remove_dot(char * s)1538 static char *remove_dot(char *s)
1539 {
1540 size_t n = strcspn(s, ".");
1541
1542 if (n && s[n]) {
1543 size_t m = strspn(s + n + 1, "0123456789");
1544 if (m && (s[n + m + 1] == '.' || s[n + m + 1] == 0))
1545 s[n] = 0;
1546 }
1547 return s;
1548 }
1549
1550 /*
1551 * The CRCs are recorded in .*.cmd files in the form of:
1552 * #SYMVER <name> <crc>
1553 */
extract_crcs_for_object(const char * object,struct module * mod)1554 static void extract_crcs_for_object(const char *object, struct module *mod)
1555 {
1556 char cmd_file[PATH_MAX];
1557 char *buf, *p;
1558 const char *base;
1559 int dirlen, ret;
1560
1561 base = strrchr(object, '/');
1562 if (base) {
1563 base++;
1564 dirlen = base - object;
1565 } else {
1566 dirlen = 0;
1567 base = object;
1568 }
1569
1570 ret = snprintf(cmd_file, sizeof(cmd_file), "%.*s.%s.cmd",
1571 dirlen, object, base);
1572 if (ret >= sizeof(cmd_file)) {
1573 error("%s: too long path was truncated\n", cmd_file);
1574 return;
1575 }
1576
1577 buf = read_text_file(cmd_file);
1578 p = buf;
1579
1580 while ((p = strstr(p, "\n#SYMVER "))) {
1581 char *name;
1582 size_t namelen;
1583 unsigned int crc;
1584 struct symbol *sym;
1585
1586 name = p + strlen("\n#SYMVER ");
1587
1588 p = strchr(name, ' ');
1589 if (!p)
1590 break;
1591
1592 namelen = p - name;
1593 p++;
1594
1595 if (!isdigit(*p))
1596 continue; /* skip this line */
1597
1598 crc = strtoul(p, &p, 0);
1599 if (*p != '\n')
1600 continue; /* skip this line */
1601
1602 name[namelen] = '\0';
1603
1604 /*
1605 * sym_find_with_module() may return NULL here.
1606 * It typically occurs when CONFIG_TRIM_UNUSED_KSYMS=y.
1607 * Since commit e1327a127703, genksyms calculates CRCs of all
1608 * symbols, including trimmed ones. Ignore orphan CRCs.
1609 */
1610 sym = sym_find_with_module(name, mod);
1611 if (sym)
1612 sym_set_crc(sym, crc);
1613 }
1614
1615 free(buf);
1616 }
1617
1618 /*
1619 * The symbol versions (CRC) are recorded in the .*.cmd files.
1620 * Parse them to retrieve CRCs for the current module.
1621 */
mod_set_crcs(struct module * mod)1622 static void mod_set_crcs(struct module *mod)
1623 {
1624 char objlist[PATH_MAX];
1625 char *buf, *p, *obj;
1626 int ret;
1627
1628 if (mod->is_vmlinux) {
1629 strcpy(objlist, ".vmlinux.objs");
1630 } else {
1631 /* objects for a module are listed in the *.mod file. */
1632 ret = snprintf(objlist, sizeof(objlist), "%s.mod", mod->name);
1633 if (ret >= sizeof(objlist)) {
1634 error("%s: too long path was truncated\n", objlist);
1635 return;
1636 }
1637 }
1638
1639 buf = read_text_file(objlist);
1640 p = buf;
1641
1642 while ((obj = strsep(&p, "\n")) && obj[0])
1643 extract_crcs_for_object(obj, mod);
1644
1645 free(buf);
1646 }
1647
read_symbols(const char * modname)1648 static void read_symbols(const char *modname)
1649 {
1650 const char *symname;
1651 char *version;
1652 char *license;
1653 char *namespace;
1654 struct module *mod;
1655 struct elf_info info = { };
1656 Elf_Sym *sym;
1657
1658 if (!parse_elf(&info, modname))
1659 return;
1660
1661 if (!strends(modname, ".o")) {
1662 error("%s: filename must be suffixed with .o\n", modname);
1663 return;
1664 }
1665
1666 /* strip trailing .o */
1667 mod = new_module(modname, strlen(modname) - strlen(".o"));
1668
1669 if (!mod->is_vmlinux) {
1670 license = get_modinfo(&info, "license");
1671 if (!license)
1672 error("missing MODULE_LICENSE() in %s\n", modname);
1673 while (license) {
1674 if (!license_is_gpl_compatible(license)) {
1675 mod->is_gpl_compatible = false;
1676 break;
1677 }
1678 license = get_next_modinfo(&info, "license", license);
1679 }
1680
1681 namespace = get_modinfo(&info, "import_ns");
1682 while (namespace) {
1683 add_namespace(&mod->imported_namespaces, namespace);
1684 namespace = get_next_modinfo(&info, "import_ns",
1685 namespace);
1686 }
1687
1688 if (extra_warn && !get_modinfo(&info, "description"))
1689 warn("missing MODULE_DESCRIPTION() in %s\n", modname);
1690 }
1691
1692 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1693 symname = remove_dot(info.strtab + sym->st_name);
1694
1695 handle_symbol(mod, &info, sym, symname);
1696 handle_moddevtable(mod, &info, sym, symname);
1697 }
1698
1699 check_sec_ref(mod, &info);
1700
1701 if (!mod->is_vmlinux) {
1702 version = get_modinfo(&info, "version");
1703 if (version || all_versions)
1704 get_src_version(mod->name, mod->srcversion,
1705 sizeof(mod->srcversion) - 1);
1706 }
1707
1708 parse_elf_finish(&info);
1709
1710 if (modversions) {
1711 /*
1712 * Our trick to get versioning for module struct etc. - it's
1713 * never passed as an argument to an exported function, so
1714 * the automatic versioning doesn't pick it up, but it's really
1715 * important anyhow.
1716 */
1717 sym_add_unresolved("module_layout", mod, false);
1718
1719 mod_set_crcs(mod);
1720 }
1721 }
1722
read_symbols_from_files(const char * filename)1723 static void read_symbols_from_files(const char *filename)
1724 {
1725 FILE *in = stdin;
1726 char fname[PATH_MAX];
1727
1728 in = fopen(filename, "r");
1729 if (!in)
1730 fatal("Can't open filenames file %s: %m", filename);
1731
1732 while (fgets(fname, PATH_MAX, in) != NULL) {
1733 if (strends(fname, "\n"))
1734 fname[strlen(fname)-1] = '\0';
1735 read_symbols(fname);
1736 }
1737
1738 fclose(in);
1739 }
1740
1741 #define SZ 500
1742
1743 /* We first write the generated file into memory using the
1744 * following helper, then compare to the file on disk and
1745 * only update the later if anything changed */
1746
buf_printf(struct buffer * buf,const char * fmt,...)1747 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
1748 const char *fmt, ...)
1749 {
1750 char tmp[SZ];
1751 int len;
1752 va_list ap;
1753
1754 va_start(ap, fmt);
1755 len = vsnprintf(tmp, SZ, fmt, ap);
1756 buf_write(buf, tmp, len);
1757 va_end(ap);
1758 }
1759
buf_write(struct buffer * buf,const char * s,int len)1760 void buf_write(struct buffer *buf, const char *s, int len)
1761 {
1762 if (buf->size - buf->pos < len) {
1763 buf->size += len + SZ;
1764 buf->p = NOFAIL(realloc(buf->p, buf->size));
1765 }
1766 strncpy(buf->p + buf->pos, s, len);
1767 buf->pos += len;
1768 }
1769
check_exports(struct module * mod)1770 static void check_exports(struct module *mod)
1771 {
1772 struct symbol *s, *exp;
1773
1774 list_for_each_entry(s, &mod->unresolved_symbols, list) {
1775 const char *basename;
1776 exp = find_symbol(s->name);
1777 if (!exp) {
1778 if (!s->weak && nr_unresolved++ < MAX_UNRESOLVED_REPORTS)
1779 modpost_log(warn_unresolved ? LOG_WARN : LOG_ERROR,
1780 "\"%s\" [%s.ko] undefined!\n",
1781 s->name, mod->name);
1782 continue;
1783 }
1784 if (exp->module == mod) {
1785 error("\"%s\" [%s.ko] was exported without definition\n",
1786 s->name, mod->name);
1787 continue;
1788 }
1789
1790 exp->used = true;
1791 s->module = exp->module;
1792 s->crc_valid = exp->crc_valid;
1793 s->crc = exp->crc;
1794
1795 basename = strrchr(mod->name, '/');
1796 if (basename)
1797 basename++;
1798 else
1799 basename = mod->name;
1800
1801 if (!contains_namespace(&mod->imported_namespaces, exp->namespace)) {
1802 modpost_log(allow_missing_ns_imports ? LOG_WARN : LOG_ERROR,
1803 "module %s uses symbol %s from namespace %s, but does not import it.\n",
1804 basename, exp->name, exp->namespace);
1805 add_namespace(&mod->missing_namespaces, exp->namespace);
1806 }
1807
1808 if (!mod->is_gpl_compatible && exp->is_gpl_only)
1809 error("GPL-incompatible module %s.ko uses GPL-only symbol '%s'\n",
1810 basename, exp->name);
1811 }
1812 }
1813
handle_white_list_exports(const char * white_list)1814 static void handle_white_list_exports(const char *white_list)
1815 {
1816 char *buf, *p, *name;
1817
1818 buf = read_text_file(white_list);
1819 p = buf;
1820
1821 while ((name = strsep(&p, "\n"))) {
1822 struct symbol *sym = find_symbol(name);
1823
1824 if (sym)
1825 sym->used = true;
1826 }
1827
1828 free(buf);
1829 }
1830
check_modname_len(struct module * mod)1831 static void check_modname_len(struct module *mod)
1832 {
1833 const char *mod_name;
1834
1835 mod_name = strrchr(mod->name, '/');
1836 if (mod_name == NULL)
1837 mod_name = mod->name;
1838 else
1839 mod_name++;
1840 if (strlen(mod_name) >= MODULE_NAME_LEN)
1841 error("module name is too long [%s.ko]\n", mod->name);
1842 }
1843
1844 /**
1845 * Header for the generated file
1846 **/
add_header(struct buffer * b,struct module * mod)1847 static void add_header(struct buffer *b, struct module *mod)
1848 {
1849 buf_printf(b, "#include <linux/module.h>\n");
1850 /*
1851 * Include build-salt.h after module.h in order to
1852 * inherit the definitions.
1853 */
1854 buf_printf(b, "#define INCLUDE_VERMAGIC\n");
1855 buf_printf(b, "#include <linux/build-salt.h>\n");
1856 buf_printf(b, "#include <linux/elfnote-lto.h>\n");
1857 buf_printf(b, "#include <linux/export-internal.h>\n");
1858 buf_printf(b, "#include <linux/vermagic.h>\n");
1859 buf_printf(b, "#include <linux/compiler.h>\n");
1860 buf_printf(b, "\n");
1861 buf_printf(b, "#ifdef CONFIG_UNWINDER_ORC\n");
1862 buf_printf(b, "#include <asm/orc_header.h>\n");
1863 buf_printf(b, "ORC_HEADER;\n");
1864 buf_printf(b, "#endif\n");
1865 buf_printf(b, "\n");
1866 buf_printf(b, "BUILD_SALT;\n");
1867 buf_printf(b, "BUILD_LTO_INFO;\n");
1868 buf_printf(b, "\n");
1869 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
1870 buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n");
1871 buf_printf(b, "\n");
1872 buf_printf(b, "__visible struct module __this_module\n");
1873 buf_printf(b, "__section(\".gnu.linkonce.this_module\") = {\n");
1874 buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
1875 if (mod->has_init)
1876 buf_printf(b, "\t.init = init_module,\n");
1877 if (mod->has_cleanup)
1878 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
1879 "\t.exit = cleanup_module,\n"
1880 "#endif\n");
1881 buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
1882 buf_printf(b, "};\n");
1883
1884 if (!external_module)
1885 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
1886
1887 buf_printf(b,
1888 "\n"
1889 "#ifdef CONFIG_RETPOLINE\n"
1890 "MODULE_INFO(retpoline, \"Y\");\n"
1891 "#endif\n");
1892
1893 if (strstarts(mod->name, "drivers/staging"))
1894 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
1895
1896 if (strstarts(mod->name, "tools/testing"))
1897 buf_printf(b, "\nMODULE_INFO(test, \"Y\");\n");
1898 }
1899
add_exported_symbols(struct buffer * buf,struct module * mod)1900 static void add_exported_symbols(struct buffer *buf, struct module *mod)
1901 {
1902 struct symbol *sym;
1903
1904 /* generate struct for exported symbols */
1905 buf_printf(buf, "\n");
1906 list_for_each_entry(sym, &mod->exported_symbols, list) {
1907 if (trim_unused_exports && !sym->used)
1908 continue;
1909
1910 buf_printf(buf, "KSYMTAB_%s(%s, \"%s\", \"%s\");\n",
1911 sym->is_func ? "FUNC" : "DATA", sym->name,
1912 sym->is_gpl_only ? "_gpl" : "", sym->namespace);
1913 }
1914
1915 if (!modversions)
1916 return;
1917
1918 /* record CRCs for exported symbols */
1919 buf_printf(buf, "\n");
1920 list_for_each_entry(sym, &mod->exported_symbols, list) {
1921 if (trim_unused_exports && !sym->used)
1922 continue;
1923
1924 if (!sym->crc_valid)
1925 warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n"
1926 "Is \"%s\" prototyped in <asm/asm-prototypes.h>?\n",
1927 sym->name, mod->name, mod->is_vmlinux ? "" : ".ko",
1928 sym->name);
1929
1930 buf_printf(buf, "SYMBOL_CRC(%s, 0x%08x, \"%s\");\n",
1931 sym->name, sym->crc, sym->is_gpl_only ? "_gpl" : "");
1932 }
1933 }
1934
1935 /**
1936 * Record CRCs for unresolved symbols
1937 **/
add_versions(struct buffer * b,struct module * mod)1938 static void add_versions(struct buffer *b, struct module *mod)
1939 {
1940 struct symbol *s;
1941
1942 if (!modversions)
1943 return;
1944
1945 buf_printf(b, "\n");
1946 buf_printf(b, "static const struct modversion_info ____versions[]\n");
1947 buf_printf(b, "__used __section(\"__versions\") = {\n");
1948
1949 list_for_each_entry(s, &mod->unresolved_symbols, list) {
1950 if (!s->module)
1951 continue;
1952 if (!s->crc_valid) {
1953 warn("\"%s\" [%s.ko] has no CRC!\n",
1954 s->name, mod->name);
1955 continue;
1956 }
1957 if (strlen(s->name) >= MODULE_NAME_LEN) {
1958 error("too long symbol \"%s\" [%s.ko]\n",
1959 s->name, mod->name);
1960 break;
1961 }
1962 buf_printf(b, "\t{ %#8x, \"%s\" },\n",
1963 s->crc, s->name);
1964 }
1965
1966 buf_printf(b, "};\n");
1967 }
1968
add_depends(struct buffer * b,struct module * mod)1969 static void add_depends(struct buffer *b, struct module *mod)
1970 {
1971 struct symbol *s;
1972 int first = 1;
1973
1974 /* Clear ->seen flag of modules that own symbols needed by this. */
1975 list_for_each_entry(s, &mod->unresolved_symbols, list) {
1976 if (s->module)
1977 s->module->seen = s->module->is_vmlinux;
1978 }
1979
1980 buf_printf(b, "\n");
1981 buf_printf(b, "MODULE_INFO(depends, \"");
1982 list_for_each_entry(s, &mod->unresolved_symbols, list) {
1983 const char *p;
1984 if (!s->module)
1985 continue;
1986
1987 if (s->module->seen)
1988 continue;
1989
1990 s->module->seen = true;
1991 p = strrchr(s->module->name, '/');
1992 if (p)
1993 p++;
1994 else
1995 p = s->module->name;
1996 buf_printf(b, "%s%s", first ? "" : ",", p);
1997 first = 0;
1998 }
1999 buf_printf(b, "\");\n");
2000 }
2001
add_srcversion(struct buffer * b,struct module * mod)2002 static void add_srcversion(struct buffer *b, struct module *mod)
2003 {
2004 if (mod->srcversion[0]) {
2005 buf_printf(b, "\n");
2006 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
2007 mod->srcversion);
2008 }
2009 }
2010
write_buf(struct buffer * b,const char * fname)2011 static void write_buf(struct buffer *b, const char *fname)
2012 {
2013 FILE *file;
2014
2015 if (error_occurred)
2016 return;
2017
2018 file = fopen(fname, "w");
2019 if (!file) {
2020 perror(fname);
2021 exit(1);
2022 }
2023 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
2024 perror(fname);
2025 exit(1);
2026 }
2027 if (fclose(file) != 0) {
2028 perror(fname);
2029 exit(1);
2030 }
2031 }
2032
write_if_changed(struct buffer * b,const char * fname)2033 static void write_if_changed(struct buffer *b, const char *fname)
2034 {
2035 char *tmp;
2036 FILE *file;
2037 struct stat st;
2038
2039 file = fopen(fname, "r");
2040 if (!file)
2041 goto write;
2042
2043 if (fstat(fileno(file), &st) < 0)
2044 goto close_write;
2045
2046 if (st.st_size != b->pos)
2047 goto close_write;
2048
2049 tmp = NOFAIL(malloc(b->pos));
2050 if (fread(tmp, 1, b->pos, file) != b->pos)
2051 goto free_write;
2052
2053 if (memcmp(tmp, b->p, b->pos) != 0)
2054 goto free_write;
2055
2056 free(tmp);
2057 fclose(file);
2058 return;
2059
2060 free_write:
2061 free(tmp);
2062 close_write:
2063 fclose(file);
2064 write:
2065 write_buf(b, fname);
2066 }
2067
write_vmlinux_export_c_file(struct module * mod)2068 static void write_vmlinux_export_c_file(struct module *mod)
2069 {
2070 struct buffer buf = { };
2071
2072 buf_printf(&buf,
2073 "#include <linux/export-internal.h>\n");
2074
2075 add_exported_symbols(&buf, mod);
2076 write_if_changed(&buf, ".vmlinux.export.c");
2077 free(buf.p);
2078 }
2079
2080 /* do sanity checks, and generate *.mod.c file */
write_mod_c_file(struct module * mod)2081 static void write_mod_c_file(struct module *mod)
2082 {
2083 struct buffer buf = { };
2084 char fname[PATH_MAX];
2085 int ret;
2086
2087 add_header(&buf, mod);
2088 add_exported_symbols(&buf, mod);
2089 add_versions(&buf, mod);
2090 add_depends(&buf, mod);
2091 add_moddevtable(&buf, mod);
2092 add_srcversion(&buf, mod);
2093
2094 ret = snprintf(fname, sizeof(fname), "%s.mod.c", mod->name);
2095 if (ret >= sizeof(fname)) {
2096 error("%s: too long path was truncated\n", fname);
2097 goto free;
2098 }
2099
2100 write_if_changed(&buf, fname);
2101
2102 free:
2103 free(buf.p);
2104 }
2105
2106 /* parse Module.symvers file. line format:
2107 * 0x12345678<tab>symbol<tab>module<tab>export<tab>namespace
2108 **/
read_dump(const char * fname)2109 static void read_dump(const char *fname)
2110 {
2111 char *buf, *pos, *line;
2112
2113 buf = read_text_file(fname);
2114 if (!buf)
2115 /* No symbol versions, silently ignore */
2116 return;
2117
2118 pos = buf;
2119
2120 while ((line = get_line(&pos))) {
2121 char *symname, *namespace, *modname, *d, *export;
2122 unsigned int crc;
2123 struct module *mod;
2124 struct symbol *s;
2125 bool gpl_only;
2126
2127 if (!(symname = strchr(line, '\t')))
2128 goto fail;
2129 *symname++ = '\0';
2130 if (!(modname = strchr(symname, '\t')))
2131 goto fail;
2132 *modname++ = '\0';
2133 if (!(export = strchr(modname, '\t')))
2134 goto fail;
2135 *export++ = '\0';
2136 if (!(namespace = strchr(export, '\t')))
2137 goto fail;
2138 *namespace++ = '\0';
2139
2140 crc = strtoul(line, &d, 16);
2141 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2142 goto fail;
2143
2144 if (!strcmp(export, "EXPORT_SYMBOL_GPL")) {
2145 gpl_only = true;
2146 } else if (!strcmp(export, "EXPORT_SYMBOL")) {
2147 gpl_only = false;
2148 } else {
2149 error("%s: unknown license %s. skip", symname, export);
2150 continue;
2151 }
2152
2153 mod = find_module(modname);
2154 if (!mod) {
2155 mod = new_module(modname, strlen(modname));
2156 mod->from_dump = true;
2157 }
2158 s = sym_add_exported(symname, mod, gpl_only, namespace);
2159 sym_set_crc(s, crc);
2160 }
2161 free(buf);
2162 return;
2163 fail:
2164 free(buf);
2165 fatal("parse error in symbol dump file\n");
2166 }
2167
write_dump(const char * fname)2168 static void write_dump(const char *fname)
2169 {
2170 struct buffer buf = { };
2171 struct module *mod;
2172 struct symbol *sym;
2173
2174 list_for_each_entry(mod, &modules, list) {
2175 if (mod->from_dump)
2176 continue;
2177 list_for_each_entry(sym, &mod->exported_symbols, list) {
2178 if (trim_unused_exports && !sym->used)
2179 continue;
2180
2181 buf_printf(&buf, "0x%08x\t%s\t%s\tEXPORT_SYMBOL%s\t%s\n",
2182 sym->crc, sym->name, mod->name,
2183 sym->is_gpl_only ? "_GPL" : "",
2184 sym->namespace);
2185 }
2186 }
2187 write_buf(&buf, fname);
2188 free(buf.p);
2189 }
2190
write_namespace_deps_files(const char * fname)2191 static void write_namespace_deps_files(const char *fname)
2192 {
2193 struct module *mod;
2194 struct namespace_list *ns;
2195 struct buffer ns_deps_buf = {};
2196
2197 list_for_each_entry(mod, &modules, list) {
2198
2199 if (mod->from_dump || list_empty(&mod->missing_namespaces))
2200 continue;
2201
2202 buf_printf(&ns_deps_buf, "%s.ko:", mod->name);
2203
2204 list_for_each_entry(ns, &mod->missing_namespaces, list)
2205 buf_printf(&ns_deps_buf, " %s", ns->namespace);
2206
2207 buf_printf(&ns_deps_buf, "\n");
2208 }
2209
2210 write_if_changed(&ns_deps_buf, fname);
2211 free(ns_deps_buf.p);
2212 }
2213
2214 struct dump_list {
2215 struct list_head list;
2216 const char *file;
2217 };
2218
main(int argc,char ** argv)2219 int main(int argc, char **argv)
2220 {
2221 struct module *mod;
2222 char *missing_namespace_deps = NULL;
2223 char *unused_exports_white_list = NULL;
2224 char *dump_write = NULL, *files_source = NULL;
2225 int opt;
2226 LIST_HEAD(dump_lists);
2227 struct dump_list *dl, *dl2;
2228
2229 while ((opt = getopt(argc, argv, "ei:MmnT:to:au:WwENd:")) != -1) {
2230 switch (opt) {
2231 case 'e':
2232 external_module = true;
2233 break;
2234 case 'i':
2235 dl = NOFAIL(malloc(sizeof(*dl)));
2236 dl->file = optarg;
2237 list_add_tail(&dl->list, &dump_lists);
2238 break;
2239 case 'M':
2240 module_enabled = true;
2241 break;
2242 case 'm':
2243 modversions = true;
2244 break;
2245 case 'n':
2246 ignore_missing_files = true;
2247 break;
2248 case 'o':
2249 dump_write = optarg;
2250 break;
2251 case 'a':
2252 all_versions = true;
2253 break;
2254 case 'T':
2255 files_source = optarg;
2256 break;
2257 case 't':
2258 trim_unused_exports = true;
2259 break;
2260 case 'u':
2261 unused_exports_white_list = optarg;
2262 break;
2263 case 'W':
2264 extra_warn = true;
2265 break;
2266 case 'w':
2267 warn_unresolved = true;
2268 break;
2269 case 'E':
2270 sec_mismatch_warn_only = false;
2271 break;
2272 case 'N':
2273 allow_missing_ns_imports = true;
2274 break;
2275 case 'd':
2276 missing_namespace_deps = optarg;
2277 break;
2278 default:
2279 exit(1);
2280 }
2281 }
2282
2283 list_for_each_entry_safe(dl, dl2, &dump_lists, list) {
2284 read_dump(dl->file);
2285 list_del(&dl->list);
2286 free(dl);
2287 }
2288
2289 while (optind < argc)
2290 read_symbols(argv[optind++]);
2291
2292 if (files_source)
2293 read_symbols_from_files(files_source);
2294
2295 list_for_each_entry(mod, &modules, list) {
2296 if (mod->from_dump || mod->is_vmlinux)
2297 continue;
2298
2299 check_modname_len(mod);
2300 check_exports(mod);
2301 }
2302
2303 if (unused_exports_white_list)
2304 handle_white_list_exports(unused_exports_white_list);
2305
2306 list_for_each_entry(mod, &modules, list) {
2307 if (mod->from_dump)
2308 continue;
2309
2310 if (mod->is_vmlinux)
2311 write_vmlinux_export_c_file(mod);
2312 else
2313 write_mod_c_file(mod);
2314 }
2315
2316 if (missing_namespace_deps)
2317 write_namespace_deps_files(missing_namespace_deps);
2318
2319 if (dump_write)
2320 write_dump(dump_write);
2321 if (sec_mismatch_count && !sec_mismatch_warn_only)
2322 error("Section mismatches detected.\n"
2323 "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");
2324
2325 if (nr_unresolved > MAX_UNRESOLVED_REPORTS)
2326 warn("suppressed %u unresolved symbol warnings because there were too many)\n",
2327 nr_unresolved - MAX_UNRESOLVED_REPORTS);
2328
2329 return error_occurred ? 1 : 0;
2330 }
2331