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
24 #include <hashtable.h>
25 #include <list.h>
26 #include "modpost.h"
27 #include "../../include/linux/license.h"
28
29 static bool module_enabled;
30 /* Are we using CONFIG_MODVERSIONS? */
31 static bool modversions;
32 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */
33 static bool all_versions;
34 /* If we are modposting external module set to 1 */
35 static bool external_module;
36 /* Only warn about unresolved symbols */
37 static bool warn_unresolved;
38
39 static int sec_mismatch_count;
40 static bool sec_mismatch_warn_only = true;
41 /* Trim EXPORT_SYMBOLs that are unused by in-tree modules */
42 static bool trim_unused_exports;
43
44 /* ignore missing files */
45 static bool ignore_missing_files;
46 /* If set to 1, only warn (instead of error) about missing ns imports */
47 static bool allow_missing_ns_imports;
48
49 static bool error_occurred;
50
51 static bool extra_warn;
52
53 /*
54 * Cut off the warnings when there are too many. This typically occurs when
55 * vmlinux is missing. ('make modules' without building vmlinux.)
56 */
57 #define MAX_UNRESOLVED_REPORTS 10
58 static unsigned int nr_unresolved;
59
60 /* In kernel, this size is defined in linux/module.h;
61 * here we use Elf_Addr instead of long for covering cross-compile
62 */
63
64 #define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
65
modpost_log(enum loglevel loglevel,const char * fmt,...)66 void modpost_log(enum loglevel loglevel, const char *fmt, ...)
67 {
68 va_list arglist;
69
70 switch (loglevel) {
71 case LOG_WARN:
72 fprintf(stderr, "WARNING: ");
73 break;
74 case LOG_ERROR:
75 fprintf(stderr, "ERROR: ");
76 error_occurred = true;
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
strends(const char * str,const char * postfix)89 static inline bool strends(const char *str, const char *postfix)
90 {
91 if (strlen(str) < strlen(postfix))
92 return false;
93
94 return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0;
95 }
96
do_nofail(void * ptr,const char * expr)97 void *do_nofail(void *ptr, const char *expr)
98 {
99 if (!ptr)
100 fatal("Memory allocation failure: %s.\n", expr);
101
102 return ptr;
103 }
104
read_text_file(const char * filename)105 char *read_text_file(const char *filename)
106 {
107 struct stat st;
108 size_t nbytes;
109 int fd;
110 char *buf;
111
112 fd = open(filename, O_RDONLY);
113 if (fd < 0) {
114 perror(filename);
115 exit(1);
116 }
117
118 if (fstat(fd, &st) < 0) {
119 perror(filename);
120 exit(1);
121 }
122
123 buf = NOFAIL(malloc(st.st_size + 1));
124
125 nbytes = st.st_size;
126
127 while (nbytes) {
128 ssize_t bytes_read;
129
130 bytes_read = read(fd, buf, nbytes);
131 if (bytes_read < 0) {
132 perror(filename);
133 exit(1);
134 }
135
136 nbytes -= bytes_read;
137 }
138 buf[st.st_size] = '\0';
139
140 close(fd);
141
142 return buf;
143 }
144
get_line(char ** stringp)145 char *get_line(char **stringp)
146 {
147 char *orig = *stringp, *next;
148
149 /* do not return the unwanted extra line at EOF */
150 if (!orig || *orig == '\0')
151 return NULL;
152
153 /* don't use strsep here, it is not available everywhere */
154 next = strchr(orig, '\n');
155 if (next)
156 *next++ = '\0';
157
158 *stringp = next;
159
160 return orig;
161 }
162
163 /* A list of all modules we processed */
164 LIST_HEAD(modules);
165
find_module(const char * modname)166 static struct module *find_module(const char *modname)
167 {
168 struct module *mod;
169
170 list_for_each_entry(mod, &modules, list) {
171 if (strcmp(mod->name, modname) == 0)
172 return mod;
173 }
174 return NULL;
175 }
176
new_module(const char * name,size_t namelen)177 static struct module *new_module(const char *name, size_t namelen)
178 {
179 struct module *mod;
180
181 mod = NOFAIL(malloc(sizeof(*mod) + namelen + 1));
182 memset(mod, 0, sizeof(*mod));
183
184 INIT_LIST_HEAD(&mod->exported_symbols);
185 INIT_LIST_HEAD(&mod->unresolved_symbols);
186 INIT_LIST_HEAD(&mod->missing_namespaces);
187 INIT_LIST_HEAD(&mod->imported_namespaces);
188
189 memcpy(mod->name, name, namelen);
190 mod->name[namelen] = '\0';
191 mod->is_vmlinux = (strcmp(mod->name, "vmlinux") == 0);
192
193 /*
194 * Set mod->is_gpl_compatible to true by default. If MODULE_LICENSE()
195 * is missing, do not check the use for EXPORT_SYMBOL_GPL() becasue
196 * modpost will exit wiht error anyway.
197 */
198 mod->is_gpl_compatible = true;
199
200 list_add_tail(&mod->list, &modules);
201
202 return mod;
203 }
204
205 struct symbol {
206 struct hlist_node hnode;/* link to hash table */
207 struct list_head list; /* link to module::exported_symbols or module::unresolved_symbols */
208 struct module *module;
209 char *namespace;
210 unsigned int crc;
211 bool crc_valid;
212 bool weak;
213 bool is_func;
214 bool is_gpl_only; /* exported by EXPORT_SYMBOL_GPL */
215 bool used; /* there exists a user of this symbol */
216 char name[];
217 };
218
219 static HASHTABLE_DEFINE(symbol_hashtable, 1U << 10);
220
221 /* This is based on the hash algorithm from gdbm, via tdb */
tdb_hash(const char * name)222 static inline unsigned int tdb_hash(const char *name)
223 {
224 unsigned value; /* Used to compute the hash value. */
225 unsigned i; /* Used to cycle through random values. */
226
227 /* Set the initial value from the key size. */
228 for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
229 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
230
231 return (1103515243 * value + 12345);
232 }
233
234 /**
235 * Allocate a new symbols for use in the hash of exported symbols or
236 * the list of unresolved symbols per module
237 **/
alloc_symbol(const char * name)238 static struct symbol *alloc_symbol(const char *name)
239 {
240 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
241
242 memset(s, 0, sizeof(*s));
243 strcpy(s->name, name);
244
245 return s;
246 }
247
248 /* For the hash of exported symbols */
hash_add_symbol(struct symbol * sym)249 static void hash_add_symbol(struct symbol *sym)
250 {
251 hash_add(symbol_hashtable, &sym->hnode, tdb_hash(sym->name));
252 }
253
sym_add_unresolved(const char * name,struct module * mod,bool weak)254 static void sym_add_unresolved(const char *name, struct module *mod, bool weak)
255 {
256 struct symbol *sym;
257
258 sym = alloc_symbol(name);
259 sym->weak = weak;
260
261 list_add_tail(&sym->list, &mod->unresolved_symbols);
262 }
263
sym_find_with_module(const char * name,struct module * mod)264 static struct symbol *sym_find_with_module(const char *name, struct module *mod)
265 {
266 struct symbol *s;
267
268 /* For our purposes, .foo matches foo. PPC64 needs this. */
269 if (name[0] == '.')
270 name++;
271
272 hash_for_each_possible(symbol_hashtable, s, hnode, tdb_hash(name)) {
273 if (strcmp(s->name, name) == 0 && (!mod || s->module == mod))
274 return s;
275 }
276 return NULL;
277 }
278
find_symbol(const char * name)279 static struct symbol *find_symbol(const char *name)
280 {
281 return sym_find_with_module(name, NULL);
282 }
283
284 struct namespace_list {
285 struct list_head list;
286 char namespace[];
287 };
288
contains_namespace(struct list_head * head,const char * namespace)289 static bool contains_namespace(struct list_head *head, const char *namespace)
290 {
291 struct namespace_list *list;
292
293 /*
294 * The default namespace is null string "", which is always implicitly
295 * contained.
296 */
297 if (!namespace[0])
298 return true;
299
300 list_for_each_entry(list, head, list) {
301 if (!strcmp(list->namespace, namespace))
302 return true;
303 }
304
305 return false;
306 }
307
add_namespace(struct list_head * head,const char * namespace)308 static void add_namespace(struct list_head *head, const char *namespace)
309 {
310 struct namespace_list *ns_entry;
311
312 if (!contains_namespace(head, namespace)) {
313 ns_entry = NOFAIL(malloc(sizeof(*ns_entry) +
314 strlen(namespace) + 1));
315 strcpy(ns_entry->namespace, namespace);
316 list_add_tail(&ns_entry->list, head);
317 }
318 }
319
sym_get_data_by_offset(const struct elf_info * info,unsigned int secindex,unsigned long offset)320 static void *sym_get_data_by_offset(const struct elf_info *info,
321 unsigned int secindex, unsigned long offset)
322 {
323 Elf_Shdr *sechdr = &info->sechdrs[secindex];
324
325 return (void *)info->hdr + sechdr->sh_offset + offset;
326 }
327
sym_get_data(const struct elf_info * info,const Elf_Sym * sym)328 void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym)
329 {
330 return sym_get_data_by_offset(info, get_secindex(info, sym),
331 sym->st_value);
332 }
333
sech_name(const struct elf_info * info,Elf_Shdr * sechdr)334 static const char *sech_name(const struct elf_info *info, Elf_Shdr *sechdr)
335 {
336 return sym_get_data_by_offset(info, info->secindex_strings,
337 sechdr->sh_name);
338 }
339
sec_name(const struct elf_info * info,unsigned int secindex)340 static const char *sec_name(const struct elf_info *info, unsigned int secindex)
341 {
342 /*
343 * If sym->st_shndx is a special section index, there is no
344 * corresponding section header.
345 * Return "" if the index is out of range of info->sechdrs[] array.
346 */
347 if (secindex >= info->num_sections)
348 return "";
349
350 return sech_name(info, &info->sechdrs[secindex]);
351 }
352
353 #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)
354
sym_add_exported(const char * name,struct module * mod,bool gpl_only,const char * namespace)355 static struct symbol *sym_add_exported(const char *name, struct module *mod,
356 bool gpl_only, const char *namespace)
357 {
358 struct symbol *s = find_symbol(name);
359
360 if (s && (!external_module || s->module->is_vmlinux || s->module == mod)) {
361 error("%s: '%s' exported twice. Previous export was in %s%s\n",
362 mod->name, name, s->module->name,
363 s->module->is_vmlinux ? "" : ".ko");
364 }
365
366 s = alloc_symbol(name);
367 s->module = mod;
368 s->is_gpl_only = gpl_only;
369 s->namespace = NOFAIL(strdup(namespace));
370 list_add_tail(&s->list, &mod->exported_symbols);
371 hash_add_symbol(s);
372
373 return s;
374 }
375
sym_set_crc(struct symbol * sym,unsigned int crc)376 static void sym_set_crc(struct symbol *sym, unsigned int crc)
377 {
378 sym->crc = crc;
379 sym->crc_valid = true;
380 }
381
grab_file(const char * filename,size_t * size)382 static void *grab_file(const char *filename, size_t *size)
383 {
384 struct stat st;
385 void *map = MAP_FAILED;
386 int fd;
387
388 fd = open(filename, O_RDONLY);
389 if (fd < 0)
390 return NULL;
391 if (fstat(fd, &st))
392 goto failed;
393
394 *size = st.st_size;
395 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
396
397 failed:
398 close(fd);
399 if (map == MAP_FAILED)
400 return NULL;
401 return map;
402 }
403
release_file(void * file,size_t size)404 static void release_file(void *file, size_t size)
405 {
406 munmap(file, size);
407 }
408
parse_elf(struct elf_info * info,const char * filename)409 static int parse_elf(struct elf_info *info, const char *filename)
410 {
411 unsigned int i;
412 Elf_Ehdr *hdr;
413 Elf_Shdr *sechdrs;
414 Elf_Sym *sym;
415 const char *secstrings;
416 unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
417
418 hdr = grab_file(filename, &info->size);
419 if (!hdr) {
420 if (ignore_missing_files) {
421 fprintf(stderr, "%s: %s (ignored)\n", filename,
422 strerror(errno));
423 return 0;
424 }
425 perror(filename);
426 exit(1);
427 }
428 info->hdr = hdr;
429 if (info->size < sizeof(*hdr)) {
430 /* file too small, assume this is an empty .o file */
431 return 0;
432 }
433 /* Is this a valid ELF file? */
434 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
435 (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
436 (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
437 (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
438 /* Not an ELF file - silently ignore it */
439 return 0;
440 }
441 /* Fix endianness in ELF header */
442 hdr->e_type = TO_NATIVE(hdr->e_type);
443 hdr->e_machine = TO_NATIVE(hdr->e_machine);
444 hdr->e_version = TO_NATIVE(hdr->e_version);
445 hdr->e_entry = TO_NATIVE(hdr->e_entry);
446 hdr->e_phoff = TO_NATIVE(hdr->e_phoff);
447 hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
448 hdr->e_flags = TO_NATIVE(hdr->e_flags);
449 hdr->e_ehsize = TO_NATIVE(hdr->e_ehsize);
450 hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
451 hdr->e_phnum = TO_NATIVE(hdr->e_phnum);
452 hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
453 hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
454 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
455 sechdrs = (void *)hdr + hdr->e_shoff;
456 info->sechdrs = sechdrs;
457
458 /* modpost only works for relocatable objects */
459 if (hdr->e_type != ET_REL)
460 fatal("%s: not relocatable object.", filename);
461
462 /* Check if file offset is correct */
463 if (hdr->e_shoff > info->size)
464 fatal("section header offset=%lu in file '%s' is bigger than filesize=%zu\n",
465 (unsigned long)hdr->e_shoff, filename, info->size);
466
467 if (hdr->e_shnum == SHN_UNDEF) {
468 /*
469 * There are more than 64k sections,
470 * read count from .sh_size.
471 */
472 info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
473 }
474 else {
475 info->num_sections = hdr->e_shnum;
476 }
477 if (hdr->e_shstrndx == SHN_XINDEX) {
478 info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
479 }
480 else {
481 info->secindex_strings = hdr->e_shstrndx;
482 }
483
484 /* Fix endianness in section headers */
485 for (i = 0; i < info->num_sections; i++) {
486 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
487 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
488 sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags);
489 sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr);
490 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
491 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
492 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
493 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info);
494 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
495 sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize);
496 }
497 /* Find symbol table. */
498 secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
499 for (i = 1; i < info->num_sections; i++) {
500 const char *secname;
501 int nobits = sechdrs[i].sh_type == SHT_NOBITS;
502
503 if (!nobits && sechdrs[i].sh_offset > info->size)
504 fatal("%s is truncated. sechdrs[i].sh_offset=%lu > sizeof(*hrd)=%zu\n",
505 filename, (unsigned long)sechdrs[i].sh_offset,
506 sizeof(*hdr));
507
508 secname = secstrings + sechdrs[i].sh_name;
509 if (strcmp(secname, ".modinfo") == 0) {
510 if (nobits)
511 fatal("%s has NOBITS .modinfo\n", filename);
512 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
513 info->modinfo_len = sechdrs[i].sh_size;
514 } else if (!strcmp(secname, ".export_symbol")) {
515 info->export_symbol_secndx = i;
516 }
517
518 if (sechdrs[i].sh_type == SHT_SYMTAB) {
519 unsigned int sh_link_idx;
520 symtab_idx = i;
521 info->symtab_start = (void *)hdr +
522 sechdrs[i].sh_offset;
523 info->symtab_stop = (void *)hdr +
524 sechdrs[i].sh_offset + sechdrs[i].sh_size;
525 sh_link_idx = sechdrs[i].sh_link;
526 info->strtab = (void *)hdr +
527 sechdrs[sh_link_idx].sh_offset;
528 }
529
530 /* 32bit section no. table? ("more than 64k sections") */
531 if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
532 symtab_shndx_idx = i;
533 info->symtab_shndx_start = (void *)hdr +
534 sechdrs[i].sh_offset;
535 info->symtab_shndx_stop = (void *)hdr +
536 sechdrs[i].sh_offset + sechdrs[i].sh_size;
537 }
538 }
539 if (!info->symtab_start)
540 fatal("%s has no symtab?\n", filename);
541
542 /* Fix endianness in symbols */
543 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
544 sym->st_shndx = TO_NATIVE(sym->st_shndx);
545 sym->st_name = TO_NATIVE(sym->st_name);
546 sym->st_value = TO_NATIVE(sym->st_value);
547 sym->st_size = TO_NATIVE(sym->st_size);
548 }
549
550 if (symtab_shndx_idx != ~0U) {
551 Elf32_Word *p;
552 if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
553 fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
554 filename, sechdrs[symtab_shndx_idx].sh_link,
555 symtab_idx);
556 /* Fix endianness */
557 for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
558 p++)
559 *p = TO_NATIVE(*p);
560 }
561
562 symsearch_init(info);
563
564 return 1;
565 }
566
parse_elf_finish(struct elf_info * info)567 static void parse_elf_finish(struct elf_info *info)
568 {
569 symsearch_finish(info);
570 release_file(info->hdr, info->size);
571 }
572
ignore_undef_symbol(struct elf_info * info,const char * symname)573 static int ignore_undef_symbol(struct elf_info *info, const char *symname)
574 {
575 /* ignore __this_module, it will be resolved shortly */
576 if (strcmp(symname, "__this_module") == 0)
577 return 1;
578 /* ignore global offset table */
579 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
580 return 1;
581 if (info->hdr->e_machine == EM_PPC)
582 /* Special register function linked on all modules during final link of .ko */
583 if (strstarts(symname, "_restgpr_") ||
584 strstarts(symname, "_savegpr_") ||
585 strstarts(symname, "_rest32gpr_") ||
586 strstarts(symname, "_save32gpr_") ||
587 strstarts(symname, "_restvr_") ||
588 strstarts(symname, "_savevr_"))
589 return 1;
590 if (info->hdr->e_machine == EM_PPC64)
591 /* Special register function linked on all modules during final link of .ko */
592 if (strstarts(symname, "_restgpr0_") ||
593 strstarts(symname, "_savegpr0_") ||
594 strstarts(symname, "_restvr_") ||
595 strstarts(symname, "_savevr_") ||
596 strcmp(symname, ".TOC.") == 0)
597 return 1;
598 /* Do not ignore this symbol */
599 return 0;
600 }
601
handle_symbol(struct module * mod,struct elf_info * info,const Elf_Sym * sym,const char * symname)602 static void handle_symbol(struct module *mod, struct elf_info *info,
603 const Elf_Sym *sym, const char *symname)
604 {
605 switch (sym->st_shndx) {
606 case SHN_COMMON:
607 if (strstarts(symname, "__gnu_lto_")) {
608 /* Should warn here, but modpost runs before the linker */
609 } else
610 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
611 break;
612 case SHN_UNDEF:
613 /* undefined symbol */
614 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
615 ELF_ST_BIND(sym->st_info) != STB_WEAK)
616 break;
617 if (ignore_undef_symbol(info, symname))
618 break;
619 if (info->hdr->e_machine == EM_SPARC ||
620 info->hdr->e_machine == EM_SPARCV9) {
621 /* Ignore register directives. */
622 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
623 break;
624 if (symname[0] == '.') {
625 char *munged = NOFAIL(strdup(symname));
626 munged[0] = '_';
627 munged[1] = toupper(munged[1]);
628 symname = munged;
629 }
630 }
631
632 sym_add_unresolved(symname, mod,
633 ELF_ST_BIND(sym->st_info) == STB_WEAK);
634 break;
635 default:
636 if (strcmp(symname, "init_module") == 0)
637 mod->has_init = true;
638 if (strcmp(symname, "cleanup_module") == 0)
639 mod->has_cleanup = true;
640 break;
641 }
642 }
643
644 /**
645 * Parse tag=value strings from .modinfo section
646 **/
next_string(char * string,unsigned long * secsize)647 static char *next_string(char *string, unsigned long *secsize)
648 {
649 /* Skip non-zero chars */
650 while (string[0]) {
651 string++;
652 if ((*secsize)-- <= 1)
653 return NULL;
654 }
655
656 /* Skip any zero padding. */
657 while (!string[0]) {
658 string++;
659 if ((*secsize)-- <= 1)
660 return NULL;
661 }
662 return string;
663 }
664
get_next_modinfo(struct elf_info * info,const char * tag,char * prev)665 static char *get_next_modinfo(struct elf_info *info, const char *tag,
666 char *prev)
667 {
668 char *p;
669 unsigned int taglen = strlen(tag);
670 char *modinfo = info->modinfo;
671 unsigned long size = info->modinfo_len;
672
673 if (prev) {
674 size -= prev - modinfo;
675 modinfo = next_string(prev, &size);
676 }
677
678 for (p = modinfo; p; p = next_string(p, &size)) {
679 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
680 return p + taglen + 1;
681 }
682 return NULL;
683 }
684
get_modinfo(struct elf_info * info,const char * tag)685 static char *get_modinfo(struct elf_info *info, const char *tag)
686
687 {
688 return get_next_modinfo(info, tag, NULL);
689 }
690
sym_name(struct elf_info * elf,Elf_Sym * sym)691 static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
692 {
693 if (sym)
694 return elf->strtab + sym->st_name;
695 else
696 return "(unknown)";
697 }
698
699 /*
700 * Check whether the 'string' argument matches one of the 'patterns',
701 * an array of shell wildcard patterns (glob).
702 *
703 * Return true is there is a match.
704 */
match(const char * string,const char * const patterns[])705 static bool match(const char *string, const char *const patterns[])
706 {
707 const char *pattern;
708
709 while ((pattern = *patterns++)) {
710 if (!fnmatch(pattern, string, 0))
711 return true;
712 }
713
714 return false;
715 }
716
717 /* useful to pass patterns to match() directly */
718 #define PATTERNS(...) \
719 ({ \
720 static const char *const patterns[] = {__VA_ARGS__, NULL}; \
721 patterns; \
722 })
723
724 /* sections that we do not want to do full section mismatch check on */
725 static const char *const section_white_list[] =
726 {
727 ".comment*",
728 ".debug*",
729 ".zdebug*", /* Compressed debug sections. */
730 ".GCC.command.line", /* record-gcc-switches */
731 ".mdebug*", /* alpha, score, mips etc. */
732 ".pdr", /* alpha, score, mips etc. */
733 ".stab*",
734 ".note*",
735 ".got*",
736 ".toc*",
737 ".xt.prop", /* xtensa */
738 ".xt.lit", /* xtensa */
739 ".arcextmap*", /* arc */
740 ".gnu.linkonce.arcext*", /* arc : modules */
741 ".cmem*", /* EZchip */
742 ".fmt_slot*", /* EZchip */
743 ".gnu.lto*",
744 ".discard.*",
745 ".llvm.call-graph-profile", /* call graph */
746 NULL
747 };
748
749 /*
750 * This is used to find sections missing the SHF_ALLOC flag.
751 * The cause of this is often a section specified in assembler
752 * without "ax" / "aw".
753 */
check_section(const char * modname,struct elf_info * elf,Elf_Shdr * sechdr)754 static void check_section(const char *modname, struct elf_info *elf,
755 Elf_Shdr *sechdr)
756 {
757 const char *sec = sech_name(elf, sechdr);
758
759 if (sechdr->sh_type == SHT_PROGBITS &&
760 !(sechdr->sh_flags & SHF_ALLOC) &&
761 !match(sec, section_white_list)) {
762 warn("%s (%s): unexpected non-allocatable section.\n"
763 "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
764 "Note that for example <linux/init.h> contains\n"
765 "section definitions for use in .S files.\n\n",
766 modname, sec);
767 }
768 }
769
770
771
772 #define ALL_INIT_DATA_SECTIONS \
773 ".init.setup", ".init.rodata", ".init.data"
774
775 #define ALL_PCI_INIT_SECTIONS \
776 ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
777 ".pci_fixup_enable", ".pci_fixup_resume", \
778 ".pci_fixup_resume_early", ".pci_fixup_suspend"
779
780 #define ALL_INIT_SECTIONS ".init.*"
781 #define ALL_EXIT_SECTIONS ".exit.*"
782
783 #define DATA_SECTIONS ".data", ".data.rel"
784 #define TEXT_SECTIONS ".text", ".text.*", ".sched.text", \
785 ".kprobes.text", ".cpuidle.text", ".noinstr.text", \
786 ".ltext", ".ltext.*"
787 #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
788 ".fixup", ".entry.text", ".exception.text", \
789 ".coldtext", ".softirqentry.text"
790
791 #define ALL_TEXT_SECTIONS ".init.text", ".exit.text", \
792 TEXT_SECTIONS, OTHER_TEXT_SECTIONS
793
794 enum mismatch {
795 TEXTDATA_TO_ANY_INIT_EXIT,
796 XXXINIT_TO_SOME_INIT,
797 ANY_INIT_TO_ANY_EXIT,
798 ANY_EXIT_TO_ANY_INIT,
799 EXTABLE_TO_NON_TEXT,
800 };
801
802 /**
803 * Describe how to match sections on different criteria:
804 *
805 * @fromsec: Array of sections to be matched.
806 *
807 * @bad_tosec: Relocations applied to a section in @fromsec to a section in
808 * this array is forbidden (black-list). Can be empty.
809 *
810 * @good_tosec: Relocations applied to a section in @fromsec must be
811 * targeting sections in this array (white-list). Can be empty.
812 *
813 * @mismatch: Type of mismatch.
814 */
815 struct sectioncheck {
816 const char *fromsec[20];
817 const char *bad_tosec[20];
818 const char *good_tosec[20];
819 enum mismatch mismatch;
820 };
821
822 static const struct sectioncheck sectioncheck[] = {
823 /* Do not reference init/exit code/data from
824 * normal code and data
825 */
826 {
827 .fromsec = { TEXT_SECTIONS, DATA_SECTIONS, NULL },
828 .bad_tosec = { ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL },
829 .mismatch = TEXTDATA_TO_ANY_INIT_EXIT,
830 },
831 /* Do not use exit code/data from init code */
832 {
833 .fromsec = { ALL_INIT_SECTIONS, NULL },
834 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
835 .mismatch = ANY_INIT_TO_ANY_EXIT,
836 },
837 /* Do not use init code/data from exit code */
838 {
839 .fromsec = { ALL_EXIT_SECTIONS, NULL },
840 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
841 .mismatch = ANY_EXIT_TO_ANY_INIT,
842 },
843 {
844 .fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
845 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
846 .mismatch = ANY_INIT_TO_ANY_EXIT,
847 },
848 {
849 .fromsec = { "__ex_table", NULL },
850 /* If you're adding any new black-listed sections in here, consider
851 * adding a special 'printer' for them in scripts/check_extable.
852 */
853 .bad_tosec = { ".altinstr_replacement", NULL },
854 .good_tosec = {ALL_TEXT_SECTIONS , NULL},
855 .mismatch = EXTABLE_TO_NON_TEXT,
856 }
857 };
858
section_mismatch(const char * fromsec,const char * tosec)859 static const struct sectioncheck *section_mismatch(
860 const char *fromsec, const char *tosec)
861 {
862 int i;
863
864 /*
865 * The target section could be the SHT_NUL section when we're
866 * handling relocations to un-resolved symbols, trying to match it
867 * doesn't make much sense and causes build failures on parisc
868 * architectures.
869 */
870 if (*tosec == '\0')
871 return NULL;
872
873 for (i = 0; i < ARRAY_SIZE(sectioncheck); i++) {
874 const struct sectioncheck *check = §ioncheck[i];
875
876 if (match(fromsec, check->fromsec)) {
877 if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
878 return check;
879 if (check->good_tosec[0] && !match(tosec, check->good_tosec))
880 return check;
881 }
882 }
883 return NULL;
884 }
885
886 /**
887 * Whitelist to allow certain references to pass with no warning.
888 *
889 * Pattern 1:
890 * If a module parameter is declared __initdata and permissions=0
891 * then this is legal despite the warning generated.
892 * We cannot see value of permissions here, so just ignore
893 * this pattern.
894 * The pattern is identified by:
895 * tosec = .init.data
896 * fromsec = .data*
897 * atsym =__param*
898 *
899 * Pattern 1a:
900 * module_param_call() ops can refer to __init set function if permissions=0
901 * The pattern is identified by:
902 * tosec = .init.text
903 * fromsec = .data*
904 * atsym = __param_ops_*
905 *
906 * Pattern 3:
907 * Whitelist all references from .head.text to any init section
908 *
909 * Pattern 4:
910 * Some symbols belong to init section but still it is ok to reference
911 * these from non-init sections as these symbols don't have any memory
912 * allocated for them and symbol address and value are same. So even
913 * if init section is freed, its ok to reference those symbols.
914 * For ex. symbols marking the init section boundaries.
915 * This pattern is identified by
916 * refsymname = __init_begin, _sinittext, _einittext
917 *
918 * Pattern 5:
919 * GCC may optimize static inlines when fed constant arg(s) resulting
920 * in functions like cpumask_empty() -- generating an associated symbol
921 * cpumask_empty.constprop.3 that appears in the audit. If the const that
922 * is passed in comes from __init, like say nmi_ipi_mask, we get a
923 * meaningless section warning. May need to add isra symbols too...
924 * This pattern is identified by
925 * tosec = init section
926 * fromsec = text section
927 * refsymname = *.constprop.*
928 *
929 **/
secref_whitelist(const char * fromsec,const char * fromsym,const char * tosec,const char * tosym)930 static int secref_whitelist(const char *fromsec, const char *fromsym,
931 const char *tosec, const char *tosym)
932 {
933 /* Check for pattern 1 */
934 if (match(tosec, PATTERNS(ALL_INIT_DATA_SECTIONS)) &&
935 match(fromsec, PATTERNS(DATA_SECTIONS)) &&
936 strstarts(fromsym, "__param"))
937 return 0;
938
939 /* Check for pattern 1a */
940 if (strcmp(tosec, ".init.text") == 0 &&
941 match(fromsec, PATTERNS(DATA_SECTIONS)) &&
942 strstarts(fromsym, "__param_ops_"))
943 return 0;
944
945 /* symbols in data sections that may refer to any init/exit sections */
946 if (match(fromsec, PATTERNS(DATA_SECTIONS)) &&
947 match(tosec, PATTERNS(ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS)) &&
948 match(fromsym, PATTERNS("*_ops", "*_probe", "*_console")))
949 return 0;
950
951 /* Check for pattern 3 */
952 if (strstarts(fromsec, ".head.text") &&
953 match(tosec, PATTERNS(ALL_INIT_SECTIONS)))
954 return 0;
955
956 /* Check for pattern 4 */
957 if (match(tosym, PATTERNS("__init_begin", "_sinittext", "_einittext")))
958 return 0;
959
960 /* Check for pattern 5 */
961 if (match(fromsec, PATTERNS(ALL_TEXT_SECTIONS)) &&
962 match(tosec, PATTERNS(ALL_INIT_SECTIONS)) &&
963 match(fromsym, PATTERNS("*.constprop.*")))
964 return 0;
965
966 return 1;
967 }
968
find_fromsym(struct elf_info * elf,Elf_Addr addr,unsigned int secndx)969 static Elf_Sym *find_fromsym(struct elf_info *elf, Elf_Addr addr,
970 unsigned int secndx)
971 {
972 return symsearch_find_nearest(elf, addr, secndx, false, ~0);
973 }
974
find_tosym(struct elf_info * elf,Elf_Addr addr,Elf_Sym * sym)975 static Elf_Sym *find_tosym(struct elf_info *elf, Elf_Addr addr, Elf_Sym *sym)
976 {
977 Elf_Sym *new_sym;
978
979 /* If the supplied symbol has a valid name, return it */
980 if (is_valid_name(elf, sym))
981 return sym;
982
983 /*
984 * Strive to find a better symbol name, but the resulting name may not
985 * match the symbol referenced in the original code.
986 */
987 new_sym = symsearch_find_nearest(elf, addr, get_secindex(elf, sym),
988 true, 20);
989 return new_sym ? new_sym : sym;
990 }
991
is_executable_section(struct elf_info * elf,unsigned int secndx)992 static bool is_executable_section(struct elf_info *elf, unsigned int secndx)
993 {
994 if (secndx >= elf->num_sections)
995 return false;
996
997 return (elf->sechdrs[secndx].sh_flags & SHF_EXECINSTR) != 0;
998 }
999
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)1000 static void default_mismatch_handler(const char *modname, struct elf_info *elf,
1001 const struct sectioncheck* const mismatch,
1002 Elf_Sym *tsym,
1003 unsigned int fsecndx, const char *fromsec, Elf_Addr faddr,
1004 const char *tosec, Elf_Addr taddr)
1005 {
1006 Elf_Sym *from;
1007 const char *tosym;
1008 const char *fromsym;
1009
1010 from = find_fromsym(elf, faddr, fsecndx);
1011 fromsym = sym_name(elf, from);
1012
1013 tsym = find_tosym(elf, taddr, tsym);
1014 tosym = sym_name(elf, tsym);
1015
1016 /* check whitelist - we may ignore it */
1017 if (!secref_whitelist(fromsec, fromsym, tosec, tosym))
1018 return;
1019
1020 sec_mismatch_count++;
1021
1022 warn("%s: section mismatch in reference: %s+0x%x (section: %s) -> %s (section: %s)\n",
1023 modname, fromsym,
1024 (unsigned int)(faddr - (from ? from->st_value : 0)),
1025 fromsec, tosym, tosec);
1026
1027 if (mismatch->mismatch == EXTABLE_TO_NON_TEXT) {
1028 if (match(tosec, mismatch->bad_tosec))
1029 fatal("The relocation at %s+0x%lx references\n"
1030 "section \"%s\" which is black-listed.\n"
1031 "Something is seriously wrong and should be fixed.\n"
1032 "You might get more information about where this is\n"
1033 "coming from by using scripts/check_extable.sh %s\n",
1034 fromsec, (long)faddr, tosec, modname);
1035 else if (is_executable_section(elf, get_secindex(elf, tsym)))
1036 warn("The relocation at %s+0x%lx references\n"
1037 "section \"%s\" which is not in the list of\n"
1038 "authorized sections. If you're adding a new section\n"
1039 "and/or if this reference is valid, add \"%s\" to the\n"
1040 "list of authorized sections to jump to on fault.\n"
1041 "This can be achieved by adding \"%s\" to\n"
1042 "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
1043 fromsec, (long)faddr, tosec, tosec, tosec);
1044 else
1045 error("%s+0x%lx references non-executable section '%s'\n",
1046 fromsec, (long)faddr, tosec);
1047 }
1048 }
1049
check_export_symbol(struct module * mod,struct elf_info * elf,Elf_Addr faddr,const char * secname,Elf_Sym * sym)1050 static void check_export_symbol(struct module *mod, struct elf_info *elf,
1051 Elf_Addr faddr, const char *secname,
1052 Elf_Sym *sym)
1053 {
1054 static const char *prefix = "__export_symbol_";
1055 const char *label_name, *name, *data;
1056 Elf_Sym *label;
1057 struct symbol *s;
1058 bool is_gpl;
1059
1060 label = find_fromsym(elf, faddr, elf->export_symbol_secndx);
1061 label_name = sym_name(elf, label);
1062
1063 if (!strstarts(label_name, prefix)) {
1064 error("%s: .export_symbol section contains strange symbol '%s'\n",
1065 mod->name, label_name);
1066 return;
1067 }
1068
1069 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
1070 ELF_ST_BIND(sym->st_info) != STB_WEAK) {
1071 error("%s: local symbol '%s' was exported\n", mod->name,
1072 label_name + strlen(prefix));
1073 return;
1074 }
1075
1076 name = sym_name(elf, sym);
1077 if (strcmp(label_name + strlen(prefix), name)) {
1078 error("%s: .export_symbol section references '%s', but it does not seem to be an export symbol\n",
1079 mod->name, name);
1080 return;
1081 }
1082
1083 data = sym_get_data(elf, label); /* license */
1084 if (!strcmp(data, "GPL")) {
1085 is_gpl = true;
1086 } else if (!strcmp(data, "")) {
1087 is_gpl = false;
1088 } else {
1089 error("%s: unknown license '%s' was specified for '%s'\n",
1090 mod->name, data, name);
1091 return;
1092 }
1093
1094 data += strlen(data) + 1; /* namespace */
1095 s = sym_add_exported(name, mod, is_gpl, data);
1096
1097 /*
1098 * We need to be aware whether we are exporting a function or
1099 * a data on some architectures.
1100 */
1101 s->is_func = (ELF_ST_TYPE(sym->st_info) == STT_FUNC);
1102
1103 /*
1104 * For parisc64, symbols prefixed $$ from the library have the symbol type
1105 * STT_LOPROC. They should be handled as functions too.
1106 */
1107 if (elf->hdr->e_ident[EI_CLASS] == ELFCLASS64 &&
1108 elf->hdr->e_machine == EM_PARISC &&
1109 ELF_ST_TYPE(sym->st_info) == STT_LOPROC)
1110 s->is_func = true;
1111
1112 if (match(secname, PATTERNS(ALL_INIT_SECTIONS)))
1113 warn("%s: %s: EXPORT_SYMBOL used for init symbol. Remove __init or EXPORT_SYMBOL.\n",
1114 mod->name, name);
1115 else if (match(secname, PATTERNS(ALL_EXIT_SECTIONS)))
1116 warn("%s: %s: EXPORT_SYMBOL used for exit symbol. Remove __exit or EXPORT_SYMBOL.\n",
1117 mod->name, name);
1118 }
1119
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)1120 static void check_section_mismatch(struct module *mod, struct elf_info *elf,
1121 Elf_Sym *sym,
1122 unsigned int fsecndx, const char *fromsec,
1123 Elf_Addr faddr, Elf_Addr taddr)
1124 {
1125 const char *tosec = sec_name(elf, get_secindex(elf, sym));
1126 const struct sectioncheck *mismatch;
1127
1128 if (module_enabled && elf->export_symbol_secndx == fsecndx) {
1129 check_export_symbol(mod, elf, faddr, tosec, sym);
1130 return;
1131 }
1132
1133 mismatch = section_mismatch(fromsec, tosec);
1134 if (!mismatch)
1135 return;
1136
1137 default_mismatch_handler(mod->name, elf, mismatch, sym,
1138 fsecndx, fromsec, faddr,
1139 tosec, taddr);
1140 }
1141
addend_386_rel(uint32_t * location,unsigned int r_type)1142 static Elf_Addr addend_386_rel(uint32_t *location, unsigned int r_type)
1143 {
1144 switch (r_type) {
1145 case R_386_32:
1146 return TO_NATIVE(*location);
1147 case R_386_PC32:
1148 return TO_NATIVE(*location) + 4;
1149 }
1150
1151 return (Elf_Addr)(-1);
1152 }
1153
sign_extend32(int32_t value,int index)1154 static int32_t sign_extend32(int32_t value, int index)
1155 {
1156 uint8_t shift = 31 - index;
1157
1158 return (int32_t)(value << shift) >> shift;
1159 }
1160
addend_arm_rel(void * loc,Elf_Sym * sym,unsigned int r_type)1161 static Elf_Addr addend_arm_rel(void *loc, Elf_Sym *sym, unsigned int r_type)
1162 {
1163 uint32_t inst, upper, lower, sign, j1, j2;
1164 int32_t offset;
1165
1166 switch (r_type) {
1167 case R_ARM_ABS32:
1168 case R_ARM_REL32:
1169 inst = TO_NATIVE(*(uint32_t *)loc);
1170 return inst + sym->st_value;
1171 case R_ARM_MOVW_ABS_NC:
1172 case R_ARM_MOVT_ABS:
1173 inst = TO_NATIVE(*(uint32_t *)loc);
1174 offset = sign_extend32(((inst & 0xf0000) >> 4) | (inst & 0xfff),
1175 15);
1176 return offset + sym->st_value;
1177 case R_ARM_PC24:
1178 case R_ARM_CALL:
1179 case R_ARM_JUMP24:
1180 inst = TO_NATIVE(*(uint32_t *)loc);
1181 offset = sign_extend32((inst & 0x00ffffff) << 2, 25);
1182 return offset + sym->st_value + 8;
1183 case R_ARM_THM_MOVW_ABS_NC:
1184 case R_ARM_THM_MOVT_ABS:
1185 upper = TO_NATIVE(*(uint16_t *)loc);
1186 lower = TO_NATIVE(*((uint16_t *)loc + 1));
1187 offset = sign_extend32(((upper & 0x000f) << 12) |
1188 ((upper & 0x0400) << 1) |
1189 ((lower & 0x7000) >> 4) |
1190 (lower & 0x00ff),
1191 15);
1192 return offset + sym->st_value;
1193 case R_ARM_THM_JUMP19:
1194 /*
1195 * Encoding T3:
1196 * S = upper[10]
1197 * imm6 = upper[5:0]
1198 * J1 = lower[13]
1199 * J2 = lower[11]
1200 * imm11 = lower[10:0]
1201 * imm32 = SignExtend(S:J2:J1:imm6:imm11:'0')
1202 */
1203 upper = TO_NATIVE(*(uint16_t *)loc);
1204 lower = TO_NATIVE(*((uint16_t *)loc + 1));
1205
1206 sign = (upper >> 10) & 1;
1207 j1 = (lower >> 13) & 1;
1208 j2 = (lower >> 11) & 1;
1209 offset = sign_extend32((sign << 20) | (j2 << 19) | (j1 << 18) |
1210 ((upper & 0x03f) << 12) |
1211 ((lower & 0x07ff) << 1),
1212 20);
1213 return offset + sym->st_value + 4;
1214 case R_ARM_THM_PC22:
1215 case R_ARM_THM_JUMP24:
1216 /*
1217 * Encoding T4:
1218 * S = upper[10]
1219 * imm10 = upper[9:0]
1220 * J1 = lower[13]
1221 * J2 = lower[11]
1222 * imm11 = lower[10:0]
1223 * I1 = NOT(J1 XOR S)
1224 * I2 = NOT(J2 XOR S)
1225 * imm32 = SignExtend(S:I1:I2:imm10:imm11:'0')
1226 */
1227 upper = TO_NATIVE(*(uint16_t *)loc);
1228 lower = TO_NATIVE(*((uint16_t *)loc + 1));
1229
1230 sign = (upper >> 10) & 1;
1231 j1 = (lower >> 13) & 1;
1232 j2 = (lower >> 11) & 1;
1233 offset = sign_extend32((sign << 24) |
1234 ((~(j1 ^ sign) & 1) << 23) |
1235 ((~(j2 ^ sign) & 1) << 22) |
1236 ((upper & 0x03ff) << 12) |
1237 ((lower & 0x07ff) << 1),
1238 24);
1239 return offset + sym->st_value + 4;
1240 }
1241
1242 return (Elf_Addr)(-1);
1243 }
1244
addend_mips_rel(uint32_t * location,unsigned int r_type)1245 static Elf_Addr addend_mips_rel(uint32_t *location, unsigned int r_type)
1246 {
1247 uint32_t inst;
1248
1249 inst = TO_NATIVE(*location);
1250 switch (r_type) {
1251 case R_MIPS_LO16:
1252 return inst & 0xffff;
1253 case R_MIPS_26:
1254 return (inst & 0x03ffffff) << 2;
1255 case R_MIPS_32:
1256 return inst;
1257 }
1258 return (Elf_Addr)(-1);
1259 }
1260
1261 #ifndef EM_RISCV
1262 #define EM_RISCV 243
1263 #endif
1264
1265 #ifndef R_RISCV_SUB32
1266 #define R_RISCV_SUB32 39
1267 #endif
1268
1269 #ifndef EM_LOONGARCH
1270 #define EM_LOONGARCH 258
1271 #endif
1272
1273 #ifndef R_LARCH_SUB32
1274 #define R_LARCH_SUB32 55
1275 #endif
1276
1277 #ifndef R_LARCH_RELAX
1278 #define R_LARCH_RELAX 100
1279 #endif
1280
1281 #ifndef R_LARCH_ALIGN
1282 #define R_LARCH_ALIGN 102
1283 #endif
1284
get_rel_type_and_sym(struct elf_info * elf,uint64_t r_info,unsigned int * r_type,unsigned int * r_sym)1285 static void get_rel_type_and_sym(struct elf_info *elf, uint64_t r_info,
1286 unsigned int *r_type, unsigned int *r_sym)
1287 {
1288 typedef struct {
1289 Elf64_Word r_sym; /* Symbol index */
1290 unsigned char r_ssym; /* Special symbol for 2nd relocation */
1291 unsigned char r_type3; /* 3rd relocation type */
1292 unsigned char r_type2; /* 2nd relocation type */
1293 unsigned char r_type; /* 1st relocation type */
1294 } Elf64_Mips_R_Info;
1295
1296 bool is_64bit = (elf->hdr->e_ident[EI_CLASS] == ELFCLASS64);
1297
1298 if (elf->hdr->e_machine == EM_MIPS && is_64bit) {
1299 Elf64_Mips_R_Info *mips64_r_info = (void *)&r_info;
1300
1301 *r_type = mips64_r_info->r_type;
1302 *r_sym = TO_NATIVE(mips64_r_info->r_sym);
1303 return;
1304 }
1305
1306 if (is_64bit)
1307 r_info = TO_NATIVE((Elf64_Xword)r_info);
1308 else
1309 r_info = TO_NATIVE((Elf32_Word)r_info);
1310
1311 *r_type = ELF_R_TYPE(r_info);
1312 *r_sym = ELF_R_SYM(r_info);
1313 }
1314
section_rela(struct module * mod,struct elf_info * elf,unsigned int fsecndx,const char * fromsec,const Elf_Rela * start,const Elf_Rela * stop)1315 static void section_rela(struct module *mod, struct elf_info *elf,
1316 unsigned int fsecndx, const char *fromsec,
1317 const Elf_Rela *start, const Elf_Rela *stop)
1318 {
1319 const Elf_Rela *rela;
1320
1321 for (rela = start; rela < stop; rela++) {
1322 Elf_Sym *tsym;
1323 Elf_Addr taddr, r_offset;
1324 unsigned int r_type, r_sym;
1325
1326 r_offset = TO_NATIVE(rela->r_offset);
1327 get_rel_type_and_sym(elf, rela->r_info, &r_type, &r_sym);
1328
1329 tsym = elf->symtab_start + r_sym;
1330 taddr = tsym->st_value + TO_NATIVE(rela->r_addend);
1331
1332 switch (elf->hdr->e_machine) {
1333 case EM_RISCV:
1334 if (!strcmp("__ex_table", fromsec) &&
1335 r_type == R_RISCV_SUB32)
1336 continue;
1337 break;
1338 case EM_LOONGARCH:
1339 switch (r_type) {
1340 case R_LARCH_SUB32:
1341 if (!strcmp("__ex_table", fromsec))
1342 continue;
1343 break;
1344 case R_LARCH_RELAX:
1345 case R_LARCH_ALIGN:
1346 /* These relocs do not refer to symbols */
1347 continue;
1348 }
1349 break;
1350 }
1351
1352 check_section_mismatch(mod, elf, tsym,
1353 fsecndx, fromsec, r_offset, taddr);
1354 }
1355 }
1356
section_rel(struct module * mod,struct elf_info * elf,unsigned int fsecndx,const char * fromsec,const Elf_Rel * start,const Elf_Rel * stop)1357 static void section_rel(struct module *mod, struct elf_info *elf,
1358 unsigned int fsecndx, const char *fromsec,
1359 const Elf_Rel *start, const Elf_Rel *stop)
1360 {
1361 const Elf_Rel *rel;
1362
1363 for (rel = start; rel < stop; rel++) {
1364 Elf_Sym *tsym;
1365 Elf_Addr taddr, r_offset;
1366 unsigned int r_type, r_sym;
1367 void *loc;
1368
1369 r_offset = TO_NATIVE(rel->r_offset);
1370 get_rel_type_and_sym(elf, rel->r_info, &r_type, &r_sym);
1371
1372 loc = sym_get_data_by_offset(elf, fsecndx, r_offset);
1373 tsym = elf->symtab_start + r_sym;
1374
1375 switch (elf->hdr->e_machine) {
1376 case EM_386:
1377 taddr = addend_386_rel(loc, r_type);
1378 break;
1379 case EM_ARM:
1380 taddr = addend_arm_rel(loc, tsym, r_type);
1381 break;
1382 case EM_MIPS:
1383 taddr = addend_mips_rel(loc, r_type);
1384 break;
1385 default:
1386 fatal("Please add code to calculate addend for this architecture\n");
1387 }
1388
1389 check_section_mismatch(mod, elf, tsym,
1390 fsecndx, fromsec, r_offset, taddr);
1391 }
1392 }
1393
1394 /**
1395 * A module includes a number of sections that are discarded
1396 * either when loaded or when used as built-in.
1397 * For loaded modules all functions marked __init and all data
1398 * marked __initdata will be discarded when the module has been initialized.
1399 * Likewise for modules used built-in the sections marked __exit
1400 * are discarded because __exit marked function are supposed to be called
1401 * only when a module is unloaded which never happens for built-in modules.
1402 * The check_sec_ref() function traverses all relocation records
1403 * to find all references to a section that reference a section that will
1404 * be discarded and warns about it.
1405 **/
check_sec_ref(struct module * mod,struct elf_info * elf)1406 static void check_sec_ref(struct module *mod, struct elf_info *elf)
1407 {
1408 int i;
1409
1410 /* Walk through all sections */
1411 for (i = 0; i < elf->num_sections; i++) {
1412 Elf_Shdr *sechdr = &elf->sechdrs[i];
1413
1414 check_section(mod->name, elf, sechdr);
1415 /* We want to process only relocation sections and not .init */
1416 if (sechdr->sh_type == SHT_REL || sechdr->sh_type == SHT_RELA) {
1417 /* section to which the relocation applies */
1418 unsigned int secndx = sechdr->sh_info;
1419 const char *secname = sec_name(elf, secndx);
1420 const void *start, *stop;
1421
1422 /* If the section is known good, skip it */
1423 if (match(secname, section_white_list))
1424 continue;
1425
1426 start = sym_get_data_by_offset(elf, i, 0);
1427 stop = start + sechdr->sh_size;
1428
1429 if (sechdr->sh_type == SHT_RELA)
1430 section_rela(mod, elf, secndx, secname,
1431 start, stop);
1432 else
1433 section_rel(mod, elf, secndx, secname,
1434 start, stop);
1435 }
1436 }
1437 }
1438
remove_dot(char * s)1439 static char *remove_dot(char *s)
1440 {
1441 size_t n = strcspn(s, ".");
1442
1443 if (n && s[n]) {
1444 size_t m = strspn(s + n + 1, "0123456789");
1445 if (m && (s[n + m + 1] == '.' || s[n + m + 1] == 0))
1446 s[n] = 0;
1447 }
1448 return s;
1449 }
1450
1451 /*
1452 * The CRCs are recorded in .*.cmd files in the form of:
1453 * #SYMVER <name> <crc>
1454 */
extract_crcs_for_object(const char * object,struct module * mod)1455 static void extract_crcs_for_object(const char *object, struct module *mod)
1456 {
1457 char cmd_file[PATH_MAX];
1458 char *buf, *p;
1459 const char *base;
1460 int dirlen, ret;
1461
1462 base = strrchr(object, '/');
1463 if (base) {
1464 base++;
1465 dirlen = base - object;
1466 } else {
1467 dirlen = 0;
1468 base = object;
1469 }
1470
1471 ret = snprintf(cmd_file, sizeof(cmd_file), "%.*s.%s.cmd",
1472 dirlen, object, base);
1473 if (ret >= sizeof(cmd_file)) {
1474 error("%s: too long path was truncated\n", cmd_file);
1475 return;
1476 }
1477
1478 buf = read_text_file(cmd_file);
1479 p = buf;
1480
1481 while ((p = strstr(p, "\n#SYMVER "))) {
1482 char *name;
1483 size_t namelen;
1484 unsigned int crc;
1485 struct symbol *sym;
1486
1487 name = p + strlen("\n#SYMVER ");
1488
1489 p = strchr(name, ' ');
1490 if (!p)
1491 break;
1492
1493 namelen = p - name;
1494 p++;
1495
1496 if (!isdigit(*p))
1497 continue; /* skip this line */
1498
1499 crc = strtoul(p, &p, 0);
1500 if (*p != '\n')
1501 continue; /* skip this line */
1502
1503 name[namelen] = '\0';
1504
1505 /*
1506 * sym_find_with_module() may return NULL here.
1507 * It typically occurs when CONFIG_TRIM_UNUSED_KSYMS=y.
1508 * Since commit e1327a127703, genksyms calculates CRCs of all
1509 * symbols, including trimmed ones. Ignore orphan CRCs.
1510 */
1511 sym = sym_find_with_module(name, mod);
1512 if (sym)
1513 sym_set_crc(sym, crc);
1514 }
1515
1516 free(buf);
1517 }
1518
1519 /*
1520 * The symbol versions (CRC) are recorded in the .*.cmd files.
1521 * Parse them to retrieve CRCs for the current module.
1522 */
mod_set_crcs(struct module * mod)1523 static void mod_set_crcs(struct module *mod)
1524 {
1525 char objlist[PATH_MAX];
1526 char *buf, *p, *obj;
1527 int ret;
1528
1529 if (mod->is_vmlinux) {
1530 strcpy(objlist, ".vmlinux.objs");
1531 } else {
1532 /* objects for a module are listed in the *.mod file. */
1533 ret = snprintf(objlist, sizeof(objlist), "%s.mod", mod->name);
1534 if (ret >= sizeof(objlist)) {
1535 error("%s: too long path was truncated\n", objlist);
1536 return;
1537 }
1538 }
1539
1540 buf = read_text_file(objlist);
1541 p = buf;
1542
1543 while ((obj = strsep(&p, "\n")) && obj[0])
1544 extract_crcs_for_object(obj, mod);
1545
1546 free(buf);
1547 }
1548
read_symbols(const char * modname)1549 static void read_symbols(const char *modname)
1550 {
1551 const char *symname;
1552 char *version;
1553 char *license;
1554 char *namespace;
1555 struct module *mod;
1556 struct elf_info info = { };
1557 Elf_Sym *sym;
1558
1559 if (!parse_elf(&info, modname))
1560 return;
1561
1562 if (!strends(modname, ".o")) {
1563 error("%s: filename must be suffixed with .o\n", modname);
1564 return;
1565 }
1566
1567 /* strip trailing .o */
1568 mod = new_module(modname, strlen(modname) - strlen(".o"));
1569
1570 if (!mod->is_vmlinux) {
1571 license = get_modinfo(&info, "license");
1572 if (!license)
1573 error("missing MODULE_LICENSE() in %s\n", modname);
1574 while (license) {
1575 if (!license_is_gpl_compatible(license)) {
1576 mod->is_gpl_compatible = false;
1577 break;
1578 }
1579 license = get_next_modinfo(&info, "license", license);
1580 }
1581
1582 namespace = get_modinfo(&info, "import_ns");
1583 while (namespace) {
1584 add_namespace(&mod->imported_namespaces, namespace);
1585 namespace = get_next_modinfo(&info, "import_ns",
1586 namespace);
1587 }
1588
1589 if (extra_warn && !get_modinfo(&info, "description"))
1590 warn("missing MODULE_DESCRIPTION() in %s\n", modname);
1591 }
1592
1593 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1594 symname = remove_dot(info.strtab + sym->st_name);
1595
1596 handle_symbol(mod, &info, sym, symname);
1597 handle_moddevtable(mod, &info, sym, symname);
1598 }
1599
1600 check_sec_ref(mod, &info);
1601
1602 if (!mod->is_vmlinux) {
1603 version = get_modinfo(&info, "version");
1604 if (version || all_versions)
1605 get_src_version(mod->name, mod->srcversion,
1606 sizeof(mod->srcversion) - 1);
1607 }
1608
1609 parse_elf_finish(&info);
1610
1611 if (modversions) {
1612 /*
1613 * Our trick to get versioning for module struct etc. - it's
1614 * never passed as an argument to an exported function, so
1615 * the automatic versioning doesn't pick it up, but it's really
1616 * important anyhow.
1617 */
1618 sym_add_unresolved("module_layout", mod, false);
1619
1620 mod_set_crcs(mod);
1621 }
1622 }
1623
read_symbols_from_files(const char * filename)1624 static void read_symbols_from_files(const char *filename)
1625 {
1626 FILE *in = stdin;
1627 char fname[PATH_MAX];
1628
1629 in = fopen(filename, "r");
1630 if (!in)
1631 fatal("Can't open filenames file %s: %m", filename);
1632
1633 while (fgets(fname, PATH_MAX, in) != NULL) {
1634 if (strends(fname, "\n"))
1635 fname[strlen(fname)-1] = '\0';
1636 read_symbols(fname);
1637 }
1638
1639 fclose(in);
1640 }
1641
1642 #define SZ 500
1643
1644 /* We first write the generated file into memory using the
1645 * following helper, then compare to the file on disk and
1646 * only update the later if anything changed */
1647
buf_printf(struct buffer * buf,const char * fmt,...)1648 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
1649 const char *fmt, ...)
1650 {
1651 char tmp[SZ];
1652 int len;
1653 va_list ap;
1654
1655 va_start(ap, fmt);
1656 len = vsnprintf(tmp, SZ, fmt, ap);
1657 buf_write(buf, tmp, len);
1658 va_end(ap);
1659 }
1660
buf_write(struct buffer * buf,const char * s,int len)1661 void buf_write(struct buffer *buf, const char *s, int len)
1662 {
1663 if (buf->size - buf->pos < len) {
1664 buf->size += len + SZ;
1665 buf->p = NOFAIL(realloc(buf->p, buf->size));
1666 }
1667 strncpy(buf->p + buf->pos, s, len);
1668 buf->pos += len;
1669 }
1670
check_exports(struct module * mod)1671 static void check_exports(struct module *mod)
1672 {
1673 struct symbol *s, *exp;
1674
1675 list_for_each_entry(s, &mod->unresolved_symbols, list) {
1676 const char *basename;
1677 exp = find_symbol(s->name);
1678 if (!exp) {
1679 if (!s->weak && nr_unresolved++ < MAX_UNRESOLVED_REPORTS)
1680 modpost_log(warn_unresolved ? LOG_WARN : LOG_ERROR,
1681 "\"%s\" [%s.ko] undefined!\n",
1682 s->name, mod->name);
1683 continue;
1684 }
1685 if (exp->module == mod) {
1686 error("\"%s\" [%s.ko] was exported without definition\n",
1687 s->name, mod->name);
1688 continue;
1689 }
1690
1691 exp->used = true;
1692 s->module = exp->module;
1693 s->crc_valid = exp->crc_valid;
1694 s->crc = exp->crc;
1695
1696 basename = strrchr(mod->name, '/');
1697 if (basename)
1698 basename++;
1699 else
1700 basename = mod->name;
1701
1702 if (!contains_namespace(&mod->imported_namespaces, exp->namespace)) {
1703 modpost_log(allow_missing_ns_imports ? LOG_WARN : LOG_ERROR,
1704 "module %s uses symbol %s from namespace %s, but does not import it.\n",
1705 basename, exp->name, exp->namespace);
1706 add_namespace(&mod->missing_namespaces, exp->namespace);
1707 }
1708
1709 if (!mod->is_gpl_compatible && exp->is_gpl_only)
1710 error("GPL-incompatible module %s.ko uses GPL-only symbol '%s'\n",
1711 basename, exp->name);
1712 }
1713 }
1714
handle_white_list_exports(const char * white_list)1715 static void handle_white_list_exports(const char *white_list)
1716 {
1717 char *buf, *p, *name;
1718
1719 buf = read_text_file(white_list);
1720 p = buf;
1721
1722 while ((name = strsep(&p, "\n"))) {
1723 struct symbol *sym = find_symbol(name);
1724
1725 if (sym)
1726 sym->used = true;
1727 }
1728
1729 free(buf);
1730 }
1731
check_modname_len(struct module * mod)1732 static void check_modname_len(struct module *mod)
1733 {
1734 const char *mod_name;
1735
1736 mod_name = strrchr(mod->name, '/');
1737 if (mod_name == NULL)
1738 mod_name = mod->name;
1739 else
1740 mod_name++;
1741 if (strlen(mod_name) >= MODULE_NAME_LEN)
1742 error("module name is too long [%s.ko]\n", mod->name);
1743 }
1744
1745 /**
1746 * Header for the generated file
1747 **/
add_header(struct buffer * b,struct module * mod)1748 static void add_header(struct buffer *b, struct module *mod)
1749 {
1750 buf_printf(b, "#include <linux/module.h>\n");
1751 /*
1752 * Include build-salt.h after module.h in order to
1753 * inherit the definitions.
1754 */
1755 buf_printf(b, "#define INCLUDE_VERMAGIC\n");
1756 buf_printf(b, "#include <linux/build-salt.h>\n");
1757 buf_printf(b, "#include <linux/elfnote-lto.h>\n");
1758 buf_printf(b, "#include <linux/export-internal.h>\n");
1759 buf_printf(b, "#include <linux/vermagic.h>\n");
1760 buf_printf(b, "#include <linux/compiler.h>\n");
1761 buf_printf(b, "\n");
1762 buf_printf(b, "#ifdef CONFIG_UNWINDER_ORC\n");
1763 buf_printf(b, "#include <asm/orc_header.h>\n");
1764 buf_printf(b, "ORC_HEADER;\n");
1765 buf_printf(b, "#endif\n");
1766 buf_printf(b, "\n");
1767 buf_printf(b, "BUILD_SALT;\n");
1768 buf_printf(b, "BUILD_LTO_INFO;\n");
1769 buf_printf(b, "\n");
1770 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
1771 buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n");
1772 buf_printf(b, "\n");
1773 buf_printf(b, "__visible struct module __this_module\n");
1774 buf_printf(b, "__section(\".gnu.linkonce.this_module\") = {\n");
1775 buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
1776 if (mod->has_init)
1777 buf_printf(b, "\t.init = init_module,\n");
1778 if (mod->has_cleanup)
1779 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
1780 "\t.exit = cleanup_module,\n"
1781 "#endif\n");
1782 buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
1783 buf_printf(b, "};\n");
1784
1785 if (!external_module)
1786 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
1787
1788 buf_printf(b,
1789 "\n"
1790 "#ifdef CONFIG_MITIGATION_RETPOLINE\n"
1791 "MODULE_INFO(retpoline, \"Y\");\n"
1792 "#endif\n");
1793
1794 if (strstarts(mod->name, "drivers/staging"))
1795 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
1796
1797 if (strstarts(mod->name, "tools/testing"))
1798 buf_printf(b, "\nMODULE_INFO(test, \"Y\");\n");
1799 }
1800
add_exported_symbols(struct buffer * buf,struct module * mod)1801 static void add_exported_symbols(struct buffer *buf, struct module *mod)
1802 {
1803 struct symbol *sym;
1804
1805 /* generate struct for exported symbols */
1806 buf_printf(buf, "\n");
1807 list_for_each_entry(sym, &mod->exported_symbols, list) {
1808 if (trim_unused_exports && !sym->used)
1809 continue;
1810
1811 buf_printf(buf, "KSYMTAB_%s(%s, \"%s\", \"%s\");\n",
1812 sym->is_func ? "FUNC" : "DATA", sym->name,
1813 sym->is_gpl_only ? "_gpl" : "", sym->namespace);
1814 }
1815
1816 if (!modversions)
1817 return;
1818
1819 /* record CRCs for exported symbols */
1820 buf_printf(buf, "\n");
1821 list_for_each_entry(sym, &mod->exported_symbols, list) {
1822 if (trim_unused_exports && !sym->used)
1823 continue;
1824
1825 if (!sym->crc_valid)
1826 warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n"
1827 "Is \"%s\" prototyped in <asm/asm-prototypes.h>?\n",
1828 sym->name, mod->name, mod->is_vmlinux ? "" : ".ko",
1829 sym->name);
1830
1831 buf_printf(buf, "SYMBOL_CRC(%s, 0x%08x, \"%s\");\n",
1832 sym->name, sym->crc, sym->is_gpl_only ? "_gpl" : "");
1833 }
1834 }
1835
1836 /**
1837 * Record CRCs for unresolved symbols
1838 **/
add_versions(struct buffer * b,struct module * mod)1839 static void add_versions(struct buffer *b, struct module *mod)
1840 {
1841 struct symbol *s;
1842
1843 if (!modversions)
1844 return;
1845
1846 buf_printf(b, "\n");
1847 buf_printf(b, "static const struct modversion_info ____versions[]\n");
1848 buf_printf(b, "__used __section(\"__versions\") = {\n");
1849
1850 list_for_each_entry(s, &mod->unresolved_symbols, list) {
1851 if (!s->module)
1852 continue;
1853 if (!s->crc_valid) {
1854 warn("\"%s\" [%s.ko] has no CRC!\n",
1855 s->name, mod->name);
1856 continue;
1857 }
1858 if (strlen(s->name) >= MODULE_NAME_LEN) {
1859 error("too long symbol \"%s\" [%s.ko]\n",
1860 s->name, mod->name);
1861 break;
1862 }
1863 buf_printf(b, "\t{ %#8x, \"%s\" },\n",
1864 s->crc, s->name);
1865 }
1866
1867 buf_printf(b, "};\n");
1868 }
1869
add_depends(struct buffer * b,struct module * mod)1870 static void add_depends(struct buffer *b, struct module *mod)
1871 {
1872 struct symbol *s;
1873 int first = 1;
1874
1875 /* Clear ->seen flag of modules that own symbols needed by this. */
1876 list_for_each_entry(s, &mod->unresolved_symbols, list) {
1877 if (s->module)
1878 s->module->seen = s->module->is_vmlinux;
1879 }
1880
1881 buf_printf(b, "\n");
1882 buf_printf(b, "MODULE_INFO(depends, \"");
1883 list_for_each_entry(s, &mod->unresolved_symbols, list) {
1884 const char *p;
1885 if (!s->module)
1886 continue;
1887
1888 if (s->module->seen)
1889 continue;
1890
1891 s->module->seen = true;
1892 p = strrchr(s->module->name, '/');
1893 if (p)
1894 p++;
1895 else
1896 p = s->module->name;
1897 buf_printf(b, "%s%s", first ? "" : ",", p);
1898 first = 0;
1899 }
1900 buf_printf(b, "\");\n");
1901 }
1902
add_srcversion(struct buffer * b,struct module * mod)1903 static void add_srcversion(struct buffer *b, struct module *mod)
1904 {
1905 if (mod->srcversion[0]) {
1906 buf_printf(b, "\n");
1907 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
1908 mod->srcversion);
1909 }
1910 }
1911
write_buf(struct buffer * b,const char * fname)1912 static void write_buf(struct buffer *b, const char *fname)
1913 {
1914 FILE *file;
1915
1916 if (error_occurred)
1917 return;
1918
1919 file = fopen(fname, "w");
1920 if (!file) {
1921 perror(fname);
1922 exit(1);
1923 }
1924 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
1925 perror(fname);
1926 exit(1);
1927 }
1928 if (fclose(file) != 0) {
1929 perror(fname);
1930 exit(1);
1931 }
1932 }
1933
write_if_changed(struct buffer * b,const char * fname)1934 static void write_if_changed(struct buffer *b, const char *fname)
1935 {
1936 char *tmp;
1937 FILE *file;
1938 struct stat st;
1939
1940 file = fopen(fname, "r");
1941 if (!file)
1942 goto write;
1943
1944 if (fstat(fileno(file), &st) < 0)
1945 goto close_write;
1946
1947 if (st.st_size != b->pos)
1948 goto close_write;
1949
1950 tmp = NOFAIL(malloc(b->pos));
1951 if (fread(tmp, 1, b->pos, file) != b->pos)
1952 goto free_write;
1953
1954 if (memcmp(tmp, b->p, b->pos) != 0)
1955 goto free_write;
1956
1957 free(tmp);
1958 fclose(file);
1959 return;
1960
1961 free_write:
1962 free(tmp);
1963 close_write:
1964 fclose(file);
1965 write:
1966 write_buf(b, fname);
1967 }
1968
write_vmlinux_export_c_file(struct module * mod)1969 static void write_vmlinux_export_c_file(struct module *mod)
1970 {
1971 struct buffer buf = { };
1972
1973 buf_printf(&buf,
1974 "#include <linux/export-internal.h>\n");
1975
1976 add_exported_symbols(&buf, mod);
1977 write_if_changed(&buf, ".vmlinux.export.c");
1978 free(buf.p);
1979 }
1980
1981 /* do sanity checks, and generate *.mod.c file */
write_mod_c_file(struct module * mod)1982 static void write_mod_c_file(struct module *mod)
1983 {
1984 struct buffer buf = { };
1985 char fname[PATH_MAX];
1986 int ret;
1987
1988 add_header(&buf, mod);
1989 add_exported_symbols(&buf, mod);
1990 add_versions(&buf, mod);
1991 add_depends(&buf, mod);
1992 add_moddevtable(&buf, mod);
1993 add_srcversion(&buf, mod);
1994
1995 ret = snprintf(fname, sizeof(fname), "%s.mod.c", mod->name);
1996 if (ret >= sizeof(fname)) {
1997 error("%s: too long path was truncated\n", fname);
1998 goto free;
1999 }
2000
2001 write_if_changed(&buf, fname);
2002
2003 free:
2004 free(buf.p);
2005 }
2006
2007 /* parse Module.symvers file. line format:
2008 * 0x12345678<tab>symbol<tab>module<tab>export<tab>namespace
2009 **/
read_dump(const char * fname)2010 static void read_dump(const char *fname)
2011 {
2012 char *buf, *pos, *line;
2013
2014 buf = read_text_file(fname);
2015 if (!buf)
2016 /* No symbol versions, silently ignore */
2017 return;
2018
2019 pos = buf;
2020
2021 while ((line = get_line(&pos))) {
2022 char *symname, *namespace, *modname, *d, *export;
2023 unsigned int crc;
2024 struct module *mod;
2025 struct symbol *s;
2026 bool gpl_only;
2027
2028 if (!(symname = strchr(line, '\t')))
2029 goto fail;
2030 *symname++ = '\0';
2031 if (!(modname = strchr(symname, '\t')))
2032 goto fail;
2033 *modname++ = '\0';
2034 if (!(export = strchr(modname, '\t')))
2035 goto fail;
2036 *export++ = '\0';
2037 if (!(namespace = strchr(export, '\t')))
2038 goto fail;
2039 *namespace++ = '\0';
2040
2041 crc = strtoul(line, &d, 16);
2042 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2043 goto fail;
2044
2045 if (!strcmp(export, "EXPORT_SYMBOL_GPL")) {
2046 gpl_only = true;
2047 } else if (!strcmp(export, "EXPORT_SYMBOL")) {
2048 gpl_only = false;
2049 } else {
2050 error("%s: unknown license %s. skip", symname, export);
2051 continue;
2052 }
2053
2054 mod = find_module(modname);
2055 if (!mod) {
2056 mod = new_module(modname, strlen(modname));
2057 mod->from_dump = true;
2058 }
2059 s = sym_add_exported(symname, mod, gpl_only, namespace);
2060 sym_set_crc(s, crc);
2061 }
2062 free(buf);
2063 return;
2064 fail:
2065 free(buf);
2066 fatal("parse error in symbol dump file\n");
2067 }
2068
write_dump(const char * fname)2069 static void write_dump(const char *fname)
2070 {
2071 struct buffer buf = { };
2072 struct module *mod;
2073 struct symbol *sym;
2074
2075 list_for_each_entry(mod, &modules, list) {
2076 if (mod->from_dump)
2077 continue;
2078 list_for_each_entry(sym, &mod->exported_symbols, list) {
2079 if (trim_unused_exports && !sym->used)
2080 continue;
2081
2082 buf_printf(&buf, "0x%08x\t%s\t%s\tEXPORT_SYMBOL%s\t%s\n",
2083 sym->crc, sym->name, mod->name,
2084 sym->is_gpl_only ? "_GPL" : "",
2085 sym->namespace);
2086 }
2087 }
2088 write_buf(&buf, fname);
2089 free(buf.p);
2090 }
2091
write_namespace_deps_files(const char * fname)2092 static void write_namespace_deps_files(const char *fname)
2093 {
2094 struct module *mod;
2095 struct namespace_list *ns;
2096 struct buffer ns_deps_buf = {};
2097
2098 list_for_each_entry(mod, &modules, list) {
2099
2100 if (mod->from_dump || list_empty(&mod->missing_namespaces))
2101 continue;
2102
2103 buf_printf(&ns_deps_buf, "%s.ko:", mod->name);
2104
2105 list_for_each_entry(ns, &mod->missing_namespaces, list)
2106 buf_printf(&ns_deps_buf, " %s", ns->namespace);
2107
2108 buf_printf(&ns_deps_buf, "\n");
2109 }
2110
2111 write_if_changed(&ns_deps_buf, fname);
2112 free(ns_deps_buf.p);
2113 }
2114
2115 struct dump_list {
2116 struct list_head list;
2117 const char *file;
2118 };
2119
main(int argc,char ** argv)2120 int main(int argc, char **argv)
2121 {
2122 struct module *mod;
2123 char *missing_namespace_deps = NULL;
2124 char *unused_exports_white_list = NULL;
2125 char *dump_write = NULL, *files_source = NULL;
2126 int opt;
2127 LIST_HEAD(dump_lists);
2128 struct dump_list *dl, *dl2;
2129
2130 while ((opt = getopt(argc, argv, "ei:MmnT:to:au:WwENd:")) != -1) {
2131 switch (opt) {
2132 case 'e':
2133 external_module = true;
2134 break;
2135 case 'i':
2136 dl = NOFAIL(malloc(sizeof(*dl)));
2137 dl->file = optarg;
2138 list_add_tail(&dl->list, &dump_lists);
2139 break;
2140 case 'M':
2141 module_enabled = true;
2142 break;
2143 case 'm':
2144 modversions = true;
2145 break;
2146 case 'n':
2147 ignore_missing_files = true;
2148 break;
2149 case 'o':
2150 dump_write = optarg;
2151 break;
2152 case 'a':
2153 all_versions = true;
2154 break;
2155 case 'T':
2156 files_source = optarg;
2157 break;
2158 case 't':
2159 trim_unused_exports = true;
2160 break;
2161 case 'u':
2162 unused_exports_white_list = optarg;
2163 break;
2164 case 'W':
2165 extra_warn = true;
2166 break;
2167 case 'w':
2168 warn_unresolved = true;
2169 break;
2170 case 'E':
2171 sec_mismatch_warn_only = false;
2172 break;
2173 case 'N':
2174 allow_missing_ns_imports = true;
2175 break;
2176 case 'd':
2177 missing_namespace_deps = optarg;
2178 break;
2179 default:
2180 exit(1);
2181 }
2182 }
2183
2184 list_for_each_entry_safe(dl, dl2, &dump_lists, list) {
2185 read_dump(dl->file);
2186 list_del(&dl->list);
2187 free(dl);
2188 }
2189
2190 while (optind < argc)
2191 read_symbols(argv[optind++]);
2192
2193 if (files_source)
2194 read_symbols_from_files(files_source);
2195
2196 list_for_each_entry(mod, &modules, list) {
2197 if (mod->from_dump || mod->is_vmlinux)
2198 continue;
2199
2200 check_modname_len(mod);
2201 check_exports(mod);
2202 }
2203
2204 if (unused_exports_white_list)
2205 handle_white_list_exports(unused_exports_white_list);
2206
2207 list_for_each_entry(mod, &modules, list) {
2208 if (mod->from_dump)
2209 continue;
2210
2211 if (mod->is_vmlinux)
2212 write_vmlinux_export_c_file(mod);
2213 else
2214 write_mod_c_file(mod);
2215 }
2216
2217 if (missing_namespace_deps)
2218 write_namespace_deps_files(missing_namespace_deps);
2219
2220 if (dump_write)
2221 write_dump(dump_write);
2222 if (sec_mismatch_count && !sec_mismatch_warn_only)
2223 error("Section mismatches detected.\n"
2224 "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");
2225
2226 if (nr_unresolved > MAX_UNRESOLVED_REPORTS)
2227 warn("suppressed %u unresolved symbol warnings because there were too many)\n",
2228 nr_unresolved - MAX_UNRESOLVED_REPORTS);
2229
2230 return error_occurred ? 1 : 0;
2231 }
2232