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Revert "tty: hvc: Fix data abort due to race in hvc_open"
[linux/fpc-iii.git] / scripts / mod / modpost.c
blob5c3c50c5ec524aaf0e5cbadca2b0d7e8e285b59b
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 <stdio.h>
17 #include <ctype.h>
18 #include <string.h>
19 #include <limits.h>
20 #include <stdbool.h>
21 #include <errno.h>
22 #include "modpost.h"
23 #include "../../include/linux/license.h"
24
25 /* Are we using CONFIG_MODVERSIONS? */
26 static int modversions = 0;
27 /* Warn about undefined symbols? (do so if we have vmlinux) */
28 static int have_vmlinux = 0;
29 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */
30 static int all_versions = 0;
31 /* If we are modposting external module set to 1 */
32 static int external_module = 0;
33 /* Warn about section mismatch in vmlinux if set to 1 */
34 static int vmlinux_section_warnings = 1;
35 /* Only warn about unresolved symbols */
36 static int warn_unresolved = 0;
37 /* How a symbol is exported */
38 static int sec_mismatch_count = 0;
39 static int sec_mismatch_fatal = 0;
40 /* ignore missing files */
41 static int ignore_missing_files;
42 /* If set to 1, only warn (instead of error) about missing ns imports */
43 static int allow_missing_ns_imports;
44
45 enum export {
46 export_plain, export_unused, export_gpl,
47 export_unused_gpl, export_gpl_future, export_unknown
48 };
49
50 /* In kernel, this size is defined in linux/module.h;
51 * here we use Elf_Addr instead of long for covering cross-compile
52 */
53
54 #define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
55
56 void __attribute__((format(printf, 2, 3)))
57 modpost_log(enum loglevel loglevel, const char *fmt, ...)
58 {
59 va_list arglist;
60
61 switch (loglevel) {
62 case LOG_WARN:
63 fprintf(stderr, "WARNING: ");
64 break;
65 case LOG_ERROR:
66 fprintf(stderr, "ERROR: ");
67 break;
68 case LOG_FATAL:
69 fprintf(stderr, "FATAL: ");
70 break;
71 default: /* invalid loglevel, ignore */
72 break;
73 }
74
75 fprintf(stderr, "modpost: ");
76
77 va_start(arglist, fmt);
78 vfprintf(stderr, fmt, arglist);
79 va_end(arglist);
80
81 if (loglevel == LOG_FATAL)
82 exit(1);
83 }
84
85 static inline bool strends(const char *str, const char *postfix)
86 {
87 if (strlen(str) < strlen(postfix))
88 return false;
89
90 return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0;
91 }
92
93 static int is_vmlinux(const char *modname)
94 {
95 const char *myname;
96
97 myname = strrchr(modname, '/');
98 if (myname)
99 myname++;
100 else
101 myname = modname;
102
103 return (strcmp(myname, "vmlinux") == 0) ||
104 (strcmp(myname, "vmlinux.o") == 0);
105 }
106
107 void *do_nofail(void *ptr, const char *expr)
108 {
109 if (!ptr)
110 fatal("Memory allocation failure: %s.\n", expr);
111
112 return ptr;
113 }
114
115 /* A list of all modules we processed */
116 static struct module *modules;
117
118 static struct module *find_module(const char *modname)
119 {
120 struct module *mod;
121
122 for (mod = modules; mod; mod = mod->next)
123 if (strcmp(mod->name, modname) == 0)
124 break;
125 return mod;
126 }
127
128 static struct module *new_module(const char *modname)
129 {
130 struct module *mod;
131 char *p;
132
133 mod = NOFAIL(malloc(sizeof(*mod)));
134 memset(mod, 0, sizeof(*mod));
135 p = NOFAIL(strdup(modname));
136
137 /* strip trailing .o */
138 if (strends(p, ".o")) {
139 p[strlen(p) - 2] = '\0';
140 mod->is_dot_o = 1;
141 }
142
143 /* add to list */
144 mod->name = p;
145 mod->gpl_compatible = -1;
146 mod->next = modules;
147 modules = mod;
148
149 return mod;
150 }
151
152 /* A hash of all exported symbols,
153 * struct symbol is also used for lists of unresolved symbols */
154
155 #define SYMBOL_HASH_SIZE 1024
156
157 struct symbol {
158 struct symbol *next;
159 struct module *module;
160 unsigned int crc;
161 int crc_valid;
162 char *namespace;
163 unsigned int weak:1;
164 unsigned int vmlinux:1; /* 1 if symbol is defined in vmlinux */
165 unsigned int kernel:1; /* 1 if symbol is from kernel
166 * (only for external modules) **/
167 unsigned int is_static:1; /* 1 if symbol is not global */
168 enum export export; /* Type of export */
169 char name[0];
170 };
171
172 static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
173
174 /* This is based on the hash agorithm from gdbm, via tdb */
175 static inline unsigned int tdb_hash(const char *name)
176 {
177 unsigned value; /* Used to compute the hash value. */
178 unsigned i; /* Used to cycle through random values. */
179
180 /* Set the initial value from the key size. */
181 for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
182 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
183
184 return (1103515243 * value + 12345);
185 }
186
187 /**
188 * Allocate a new symbols for use in the hash of exported symbols or
189 * the list of unresolved symbols per module
190 **/
191 static struct symbol *alloc_symbol(const char *name, unsigned int weak,
192 struct symbol *next)
193 {
194 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
195
196 memset(s, 0, sizeof(*s));
197 strcpy(s->name, name);
198 s->weak = weak;
199 s->next = next;
200 s->is_static = 1;
201 return s;
202 }
203
204 /* For the hash of exported symbols */
205 static struct symbol *new_symbol(const char *name, struct module *module,
206 enum export export)
207 {
208 unsigned int hash;
209
210 hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
211 symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
212
213 return symbolhash[hash];
214 }
215
216 static struct symbol *find_symbol(const char *name)
217 {
218 struct symbol *s;
219
220 /* For our purposes, .foo matches foo. PPC64 needs this. */
221 if (name[0] == '.')
222 name++;
223
224 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
225 if (strcmp(s->name, name) == 0)
226 return s;
227 }
228 return NULL;
229 }
230
231 static bool contains_namespace(struct namespace_list *list,
232 const char *namespace)
233 {
234 for (; list; list = list->next)
235 if (!strcmp(list->namespace, namespace))
236 return true;
237
238 return false;
239 }
240
241 static void add_namespace(struct namespace_list **list, const char *namespace)
242 {
243 struct namespace_list *ns_entry;
244
245 if (!contains_namespace(*list, namespace)) {
246 ns_entry = NOFAIL(malloc(sizeof(struct namespace_list) +
247 strlen(namespace) + 1));
248 strcpy(ns_entry->namespace, namespace);
249 ns_entry->next = *list;
250 *list = ns_entry;
251 }
252 }
253
254 static bool module_imports_namespace(struct module *module,
255 const char *namespace)
256 {
257 return contains_namespace(module->imported_namespaces, namespace);
258 }
259
260 static const struct {
261 const char *str;
262 enum export export;
263 } export_list[] = {
264 { .str = "EXPORT_SYMBOL", .export = export_plain },
265 { .str = "EXPORT_UNUSED_SYMBOL", .export = export_unused },
266 { .str = "EXPORT_SYMBOL_GPL", .export = export_gpl },
267 { .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
268 { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
269 { .str = "(unknown)", .export = export_unknown },
270 };
271
272
273 static const char *export_str(enum export ex)
274 {
275 return export_list[ex].str;
276 }
277
278 static enum export export_no(const char *s)
279 {
280 int i;
281
282 if (!s)
283 return export_unknown;
284 for (i = 0; export_list[i].export != export_unknown; i++) {
285 if (strcmp(export_list[i].str, s) == 0)
286 return export_list[i].export;
287 }
288 return export_unknown;
289 }
290
291 static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr)
292 {
293 return (void *)elf->hdr +
294 elf->sechdrs[elf->secindex_strings].sh_offset +
295 sechdr->sh_name;
296 }
297
298 static const char *sec_name(struct elf_info *elf, int secindex)
299 {
300 return sech_name(elf, &elf->sechdrs[secindex]);
301 }
302
303 static void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym)
304 {
305 unsigned int secindex = get_secindex(info, sym);
306 Elf_Shdr *sechdr = &info->sechdrs[secindex];
307 unsigned long offset;
308
309 offset = sym->st_value;
310 if (info->hdr->e_type != ET_REL)
311 offset -= sechdr->sh_addr;
312
313 return (void *)info->hdr + sechdr->sh_offset + offset;
314 }
315
316 #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)
317
318 static enum export export_from_secname(struct elf_info *elf, unsigned int sec)
319 {
320 const char *secname = sec_name(elf, sec);
321
322 if (strstarts(secname, "___ksymtab+"))
323 return export_plain;
324 else if (strstarts(secname, "___ksymtab_unused+"))
325 return export_unused;
326 else if (strstarts(secname, "___ksymtab_gpl+"))
327 return export_gpl;
328 else if (strstarts(secname, "___ksymtab_unused_gpl+"))
329 return export_unused_gpl;
330 else if (strstarts(secname, "___ksymtab_gpl_future+"))
331 return export_gpl_future;
332 else
333 return export_unknown;
334 }
335
336 static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
337 {
338 if (sec == elf->export_sec)
339 return export_plain;
340 else if (sec == elf->export_unused_sec)
341 return export_unused;
342 else if (sec == elf->export_gpl_sec)
343 return export_gpl;
344 else if (sec == elf->export_unused_gpl_sec)
345 return export_unused_gpl;
346 else if (sec == elf->export_gpl_future_sec)
347 return export_gpl_future;
348 else
349 return export_unknown;
350 }
351
352 static const char *namespace_from_kstrtabns(const struct elf_info *info,
353 const Elf_Sym *sym)
354 {
355 const char *value = sym_get_data(info, sym);
356 return value[0] ? value : NULL;
357 }
358
359 static void sym_update_namespace(const char *symname, const char *namespace)
360 {
361 struct symbol *s = find_symbol(symname);
362
363 /*
364 * That symbol should have been created earlier and thus this is
365 * actually an assertion.
366 */
367 if (!s) {
368 merror("Could not update namespace(%s) for symbol %s\n",
369 namespace, symname);
370 return;
371 }
372
373 free(s->namespace);
374 s->namespace =
375 namespace && namespace[0] ? NOFAIL(strdup(namespace)) : NULL;
376 }
377
378 /**
379 * Add an exported symbol - it may have already been added without a
380 * CRC, in this case just update the CRC
381 **/
382 static struct symbol *sym_add_exported(const char *name, struct module *mod,
383 enum export export)
384 {
385 struct symbol *s = find_symbol(name);
386
387 if (!s) {
388 s = new_symbol(name, mod, export);
389 } else if (!external_module || is_vmlinux(s->module->name) ||
390 s->module == mod) {
391 warn("%s: '%s' exported twice. Previous export was in %s%s\n",
392 mod->name, name, s->module->name,
393 is_vmlinux(s->module->name) ? "" : ".ko");
394 return s;
395 }
396
397 s->module = mod;
398 s->vmlinux = is_vmlinux(mod->name);
399 s->kernel = 0;
400 s->export = export;
401 return s;
402 }
403
404 static void sym_set_crc(const char *name, unsigned int crc)
405 {
406 struct symbol *s = find_symbol(name);
407
408 /*
409 * Ignore stand-alone __crc_*, which might be auto-generated symbols
410 * such as __*_veneer in ARM ELF.
411 */
412 if (!s)
413 return;
414
415 s->crc = crc;
416 s->crc_valid = 1;
417 }
418
419 void *grab_file(const char *filename, unsigned long *size)
420 {
421 struct stat st;
422 void *map = MAP_FAILED;
423 int fd;
424
425 fd = open(filename, O_RDONLY);
426 if (fd < 0)
427 return NULL;
428 if (fstat(fd, &st))
429 goto failed;
430
431 *size = st.st_size;
432 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
433
434 failed:
435 close(fd);
436 if (map == MAP_FAILED)
437 return NULL;
438 return map;
439 }
440
441 /**
442 * Return a copy of the next line in a mmap'ed file.
443 * spaces in the beginning of the line is trimmed away.
444 * Return a pointer to a static buffer.
445 **/
446 char *get_next_line(unsigned long *pos, void *file, unsigned long size)
447 {
448 static char line[4096];
449 int skip = 1;
450 size_t len = 0;
451 signed char *p = (signed char *)file + *pos;
452 char *s = line;
453
454 for (; *pos < size ; (*pos)++) {
455 if (skip && isspace(*p)) {
456 p++;
457 continue;
458 }
459 skip = 0;
460 if (*p != '\n' && (*pos < size)) {
461 len++;
462 *s++ = *p++;
463 if (len > 4095)
464 break; /* Too long, stop */
465 } else {
466 /* End of string */
467 *s = '\0';
468 return line;
469 }
470 }
471 /* End of buffer */
472 return NULL;
473 }
474
475 void release_file(void *file, unsigned long size)
476 {
477 munmap(file, size);
478 }
479
480 static int parse_elf(struct elf_info *info, const char *filename)
481 {
482 unsigned int i;
483 Elf_Ehdr *hdr;
484 Elf_Shdr *sechdrs;
485 Elf_Sym *sym;
486 const char *secstrings;
487 unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
488
489 hdr = grab_file(filename, &info->size);
490 if (!hdr) {
491 if (ignore_missing_files) {
492 fprintf(stderr, "%s: %s (ignored)\n", filename,
493 strerror(errno));
494 return 0;
495 }
496 perror(filename);
497 exit(1);
498 }
499 info->hdr = hdr;
500 if (info->size < sizeof(*hdr)) {
501 /* file too small, assume this is an empty .o file */
502 return 0;
503 }
504 /* Is this a valid ELF file? */
505 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
506 (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
507 (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
508 (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
509 /* Not an ELF file - silently ignore it */
510 return 0;
511 }
512 /* Fix endianness in ELF header */
513 hdr->e_type = TO_NATIVE(hdr->e_type);
514 hdr->e_machine = TO_NATIVE(hdr->e_machine);
515 hdr->e_version = TO_NATIVE(hdr->e_version);
516 hdr->e_entry = TO_NATIVE(hdr->e_entry);
517 hdr->e_phoff = TO_NATIVE(hdr->e_phoff);
518 hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
519 hdr->e_flags = TO_NATIVE(hdr->e_flags);
520 hdr->e_ehsize = TO_NATIVE(hdr->e_ehsize);
521 hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
522 hdr->e_phnum = TO_NATIVE(hdr->e_phnum);
523 hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
524 hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
525 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
526 sechdrs = (void *)hdr + hdr->e_shoff;
527 info->sechdrs = sechdrs;
528
529 /* Check if file offset is correct */
530 if (hdr->e_shoff > info->size) {
531 fatal("section header offset=%lu in file '%s' is bigger than "
532 "filesize=%lu\n", (unsigned long)hdr->e_shoff,
533 filename, info->size);
534 return 0;
535 }
536
537 if (hdr->e_shnum == SHN_UNDEF) {
538 /*
539 * There are more than 64k sections,
540 * read count from .sh_size.
541 */
542 info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
543 }
544 else {
545 info->num_sections = hdr->e_shnum;
546 }
547 if (hdr->e_shstrndx == SHN_XINDEX) {
548 info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
549 }
550 else {
551 info->secindex_strings = hdr->e_shstrndx;
552 }
553
554 /* Fix endianness in section headers */
555 for (i = 0; i < info->num_sections; i++) {
556 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
557 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
558 sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags);
559 sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr);
560 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
561 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
562 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
563 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info);
564 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
565 sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize);
566 }
567 /* Find symbol table. */
568 secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
569 for (i = 1; i < info->num_sections; i++) {
570 const char *secname;
571 int nobits = sechdrs[i].sh_type == SHT_NOBITS;
572
573 if (!nobits && sechdrs[i].sh_offset > info->size) {
574 fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
575 "sizeof(*hrd)=%zu\n", filename,
576 (unsigned long)sechdrs[i].sh_offset,
577 sizeof(*hdr));
578 return 0;
579 }
580 secname = secstrings + sechdrs[i].sh_name;
581 if (strcmp(secname, ".modinfo") == 0) {
582 if (nobits)
583 fatal("%s has NOBITS .modinfo\n", filename);
584 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
585 info->modinfo_len = sechdrs[i].sh_size;
586 } else if (strcmp(secname, "__ksymtab") == 0)
587 info->export_sec = i;
588 else if (strcmp(secname, "__ksymtab_unused") == 0)
589 info->export_unused_sec = i;
590 else if (strcmp(secname, "__ksymtab_gpl") == 0)
591 info->export_gpl_sec = i;
592 else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
593 info->export_unused_gpl_sec = i;
594 else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
595 info->export_gpl_future_sec = i;
596
597 if (sechdrs[i].sh_type == SHT_SYMTAB) {
598 unsigned int sh_link_idx;
599 symtab_idx = i;
600 info->symtab_start = (void *)hdr +
601 sechdrs[i].sh_offset;
602 info->symtab_stop = (void *)hdr +
603 sechdrs[i].sh_offset + sechdrs[i].sh_size;
604 sh_link_idx = sechdrs[i].sh_link;
605 info->strtab = (void *)hdr +
606 sechdrs[sh_link_idx].sh_offset;
607 }
608
609 /* 32bit section no. table? ("more than 64k sections") */
610 if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
611 symtab_shndx_idx = i;
612 info->symtab_shndx_start = (void *)hdr +
613 sechdrs[i].sh_offset;
614 info->symtab_shndx_stop = (void *)hdr +
615 sechdrs[i].sh_offset + sechdrs[i].sh_size;
616 }
617 }
618 if (!info->symtab_start)
619 fatal("%s has no symtab?\n", filename);
620
621 /* Fix endianness in symbols */
622 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
623 sym->st_shndx = TO_NATIVE(sym->st_shndx);
624 sym->st_name = TO_NATIVE(sym->st_name);
625 sym->st_value = TO_NATIVE(sym->st_value);
626 sym->st_size = TO_NATIVE(sym->st_size);
627 }
628
629 if (symtab_shndx_idx != ~0U) {
630 Elf32_Word *p;
631 if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
632 fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
633 filename, sechdrs[symtab_shndx_idx].sh_link,
634 symtab_idx);
635 /* Fix endianness */
636 for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
637 p++)
638 *p = TO_NATIVE(*p);
639 }
640
641 return 1;
642 }
643
644 static void parse_elf_finish(struct elf_info *info)
645 {
646 release_file(info->hdr, info->size);
647 }
648
649 static int ignore_undef_symbol(struct elf_info *info, const char *symname)
650 {
651 /* ignore __this_module, it will be resolved shortly */
652 if (strcmp(symname, "__this_module") == 0)
653 return 1;
654 /* ignore global offset table */
655 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
656 return 1;
657 if (info->hdr->e_machine == EM_PPC)
658 /* Special register function linked on all modules during final link of .ko */
659 if (strstarts(symname, "_restgpr_") ||
660 strstarts(symname, "_savegpr_") ||
661 strstarts(symname, "_rest32gpr_") ||
662 strstarts(symname, "_save32gpr_") ||
663 strstarts(symname, "_restvr_") ||
664 strstarts(symname, "_savevr_"))
665 return 1;
666 if (info->hdr->e_machine == EM_PPC64)
667 /* Special register function linked on all modules during final link of .ko */
668 if (strstarts(symname, "_restgpr0_") ||
669 strstarts(symname, "_savegpr0_") ||
670 strstarts(symname, "_restvr_") ||
671 strstarts(symname, "_savevr_") ||
672 strcmp(symname, ".TOC.") == 0)
673 return 1;
674 /* Do not ignore this symbol */
675 return 0;
676 }
677
678 static void handle_modversion(const struct module *mod,
679 const struct elf_info *info,
680 const Elf_Sym *sym, const char *symname)
681 {
682 unsigned int crc;
683
684 if (sym->st_shndx == SHN_UNDEF) {
685 warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n",
686 symname, mod->name, is_vmlinux(mod->name) ? "":".ko");
687 return;
688 }
689
690 if (sym->st_shndx == SHN_ABS) {
691 crc = sym->st_value;
692 } else {
693 unsigned int *crcp;
694
695 /* symbol points to the CRC in the ELF object */
696 crcp = sym_get_data(info, sym);
697 crc = TO_NATIVE(*crcp);
698 }
699 sym_set_crc(symname, crc);
700 }
701
702 static void handle_symbol(struct module *mod, struct elf_info *info,
703 const Elf_Sym *sym, const char *symname)
704 {
705 enum export export;
706 const char *name;
707
708 if ((!is_vmlinux(mod->name) || mod->is_dot_o) &&
709 strstarts(symname, "__ksymtab"))
710 export = export_from_secname(info, get_secindex(info, sym));
711 else
712 export = export_from_sec(info, get_secindex(info, sym));
713
714 switch (sym->st_shndx) {
715 case SHN_COMMON:
716 if (strstarts(symname, "__gnu_lto_")) {
717 /* Should warn here, but modpost runs before the linker */
718 } else
719 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
720 break;
721 case SHN_UNDEF:
722 /* undefined symbol */
723 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
724 ELF_ST_BIND(sym->st_info) != STB_WEAK)
725 break;
726 if (ignore_undef_symbol(info, symname))
727 break;
728 if (info->hdr->e_machine == EM_SPARC ||
729 info->hdr->e_machine == EM_SPARCV9) {
730 /* Ignore register directives. */
731 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
732 break;
733 if (symname[0] == '.') {
734 char *munged = NOFAIL(strdup(symname));
735 munged[0] = '_';
736 munged[1] = toupper(munged[1]);
737 symname = munged;
738 }
739 }
740
741 mod->unres = alloc_symbol(symname,
742 ELF_ST_BIND(sym->st_info) == STB_WEAK,
743 mod->unres);
744 break;
745 default:
746 /* All exported symbols */
747 if (strstarts(symname, "__ksymtab_")) {
748 name = symname + strlen("__ksymtab_");
749 sym_add_exported(name, mod, export);
750 }
751 if (strcmp(symname, "init_module") == 0)
752 mod->has_init = 1;
753 if (strcmp(symname, "cleanup_module") == 0)
754 mod->has_cleanup = 1;
755 break;
756 }
757 }
758
759 /**
760 * Parse tag=value strings from .modinfo section
761 **/
762 static char *next_string(char *string, unsigned long *secsize)
763 {
764 /* Skip non-zero chars */
765 while (string[0]) {
766 string++;
767 if ((*secsize)-- <= 1)
768 return NULL;
769 }
770
771 /* Skip any zero padding. */
772 while (!string[0]) {
773 string++;
774 if ((*secsize)-- <= 1)
775 return NULL;
776 }
777 return string;
778 }
779
780 static char *get_next_modinfo(struct elf_info *info, const char *tag,
781 char *prev)
782 {
783 char *p;
784 unsigned int taglen = strlen(tag);
785 char *modinfo = info->modinfo;
786 unsigned long size = info->modinfo_len;
787
788 if (prev) {
789 size -= prev - modinfo;
790 modinfo = next_string(prev, &size);
791 }
792
793 for (p = modinfo; p; p = next_string(p, &size)) {
794 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
795 return p + taglen + 1;
796 }
797 return NULL;
798 }
799
800 static char *get_modinfo(struct elf_info *info, const char *tag)
801
802 {
803 return get_next_modinfo(info, tag, NULL);
804 }
805
806 /**
807 * Test if string s ends in string sub
808 * return 0 if match
809 **/
810 static int strrcmp(const char *s, const char *sub)
811 {
812 int slen, sublen;
813
814 if (!s || !sub)
815 return 1;
816
817 slen = strlen(s);
818 sublen = strlen(sub);
819
820 if ((slen == 0) || (sublen == 0))
821 return 1;
822
823 if (sublen > slen)
824 return 1;
825
826 return memcmp(s + slen - sublen, sub, sublen);
827 }
828
829 static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
830 {
831 if (sym)
832 return elf->strtab + sym->st_name;
833 else
834 return "(unknown)";
835 }
836
837 /* The pattern is an array of simple patterns.
838 * "foo" will match an exact string equal to "foo"
839 * "*foo" will match a string that ends with "foo"
840 * "foo*" will match a string that begins with "foo"
841 * "*foo*" will match a string that contains "foo"
842 */
843 static int match(const char *sym, const char * const pat[])
844 {
845 const char *p;
846 while (*pat) {
847 p = *pat++;
848 const char *endp = p + strlen(p) - 1;
849
850 /* "*foo*" */
851 if (*p == '*' && *endp == '*') {
852 char *bare = NOFAIL(strndup(p + 1, strlen(p) - 2));
853 char *here = strstr(sym, bare);
854
855 free(bare);
856 if (here != NULL)
857 return 1;
858 }
859 /* "*foo" */
860 else if (*p == '*') {
861 if (strrcmp(sym, p + 1) == 0)
862 return 1;
863 }
864 /* "foo*" */
865 else if (*endp == '*') {
866 if (strncmp(sym, p, strlen(p) - 1) == 0)
867 return 1;
868 }
869 /* no wildcards */
870 else {
871 if (strcmp(p, sym) == 0)
872 return 1;
873 }
874 }
875 /* no match */
876 return 0;
877 }
878
879 /* sections that we do not want to do full section mismatch check on */
880 static const char *const section_white_list[] =
881 {
882 ".comment*",
883 ".debug*",
884 ".cranges", /* sh64 */
885 ".zdebug*", /* Compressed debug sections. */
886 ".GCC.command.line", /* record-gcc-switches */
887 ".mdebug*", /* alpha, score, mips etc. */
888 ".pdr", /* alpha, score, mips etc. */
889 ".stab*",
890 ".note*",
891 ".got*",
892 ".toc*",
893 ".xt.prop", /* xtensa */
894 ".xt.lit", /* xtensa */
895 ".arcextmap*", /* arc */
896 ".gnu.linkonce.arcext*", /* arc : modules */
897 ".cmem*", /* EZchip */
898 ".fmt_slot*", /* EZchip */
899 ".gnu.lto*",
900 ".discard.*",
901 NULL
902 };
903
904 /*
905 * This is used to find sections missing the SHF_ALLOC flag.
906 * The cause of this is often a section specified in assembler
907 * without "ax" / "aw".
908 */
909 static void check_section(const char *modname, struct elf_info *elf,
910 Elf_Shdr *sechdr)
911 {
912 const char *sec = sech_name(elf, sechdr);
913
914 if (sechdr->sh_type == SHT_PROGBITS &&
915 !(sechdr->sh_flags & SHF_ALLOC) &&
916 !match(sec, section_white_list)) {
917 warn("%s (%s): unexpected non-allocatable section.\n"
918 "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
919 "Note that for example <linux/init.h> contains\n"
920 "section definitions for use in .S files.\n\n",
921 modname, sec);
922 }
923 }
924
925
926
927 #define ALL_INIT_DATA_SECTIONS \
928 ".init.setup", ".init.rodata", ".meminit.rodata", \
929 ".init.data", ".meminit.data"
930 #define ALL_EXIT_DATA_SECTIONS \
931 ".exit.data", ".memexit.data"
932
933 #define ALL_INIT_TEXT_SECTIONS \
934 ".init.text", ".meminit.text"
935 #define ALL_EXIT_TEXT_SECTIONS \
936 ".exit.text", ".memexit.text"
937
938 #define ALL_PCI_INIT_SECTIONS \
939 ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
940 ".pci_fixup_enable", ".pci_fixup_resume", \
941 ".pci_fixup_resume_early", ".pci_fixup_suspend"
942
943 #define ALL_XXXINIT_SECTIONS MEM_INIT_SECTIONS
944 #define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS
945
946 #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
947 #define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
948
949 #define DATA_SECTIONS ".data", ".data.rel"
950 #define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \
951 ".kprobes.text", ".cpuidle.text"
952 #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
953 ".fixup", ".entry.text", ".exception.text", ".text.*", \
954 ".coldtext"
955
956 #define INIT_SECTIONS ".init.*"
957 #define MEM_INIT_SECTIONS ".meminit.*"
958
959 #define EXIT_SECTIONS ".exit.*"
960 #define MEM_EXIT_SECTIONS ".memexit.*"
961
962 #define ALL_TEXT_SECTIONS ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \
963 TEXT_SECTIONS, OTHER_TEXT_SECTIONS
964
965 /* init data sections */
966 static const char *const init_data_sections[] =
967 { ALL_INIT_DATA_SECTIONS, NULL };
968
969 /* all init sections */
970 static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL };
971
972 /* All init and exit sections (code + data) */
973 static const char *const init_exit_sections[] =
974 {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
975
976 /* all text sections */
977 static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL };
978
979 /* data section */
980 static const char *const data_sections[] = { DATA_SECTIONS, NULL };
981
982
983 /* symbols in .data that may refer to init/exit sections */
984 #define DEFAULT_SYMBOL_WHITE_LIST \
985 "*driver", \
986 "*_template", /* scsi uses *_template a lot */ \
987 "*_timer", /* arm uses ops structures named _timer a lot */ \
988 "*_sht", /* scsi also used *_sht to some extent */ \
989 "*_ops", \
990 "*_probe", \
991 "*_probe_one", \
992 "*_console"
993
994 static const char *const head_sections[] = { ".head.text*", NULL };
995 static const char *const linker_symbols[] =
996 { "__init_begin", "_sinittext", "_einittext", NULL };
997 static const char *const optim_symbols[] = { "*.constprop.*", NULL };
998
999 enum mismatch {
1000 TEXT_TO_ANY_INIT,
1001 DATA_TO_ANY_INIT,
1002 TEXT_TO_ANY_EXIT,
1003 DATA_TO_ANY_EXIT,
1004 XXXINIT_TO_SOME_INIT,
1005 XXXEXIT_TO_SOME_EXIT,
1006 ANY_INIT_TO_ANY_EXIT,
1007 ANY_EXIT_TO_ANY_INIT,
1008 EXPORT_TO_INIT_EXIT,
1009 EXTABLE_TO_NON_TEXT,
1010 };
1011
1012 /**
1013 * Describe how to match sections on different criterias:
1014 *
1015 * @fromsec: Array of sections to be matched.
1016 *
1017 * @bad_tosec: Relocations applied to a section in @fromsec to a section in
1018 * this array is forbidden (black-list). Can be empty.
1019 *
1020 * @good_tosec: Relocations applied to a section in @fromsec must be
1021 * targetting sections in this array (white-list). Can be empty.
1022 *
1023 * @mismatch: Type of mismatch.
1024 *
1025 * @symbol_white_list: Do not match a relocation to a symbol in this list
1026 * even if it is targetting a section in @bad_to_sec.
1027 *
1028 * @handler: Specific handler to call when a match is found. If NULL,
1029 * default_mismatch_handler() will be called.
1030 *
1031 */
1032 struct sectioncheck {
1033 const char *fromsec[20];
1034 const char *bad_tosec[20];
1035 const char *good_tosec[20];
1036 enum mismatch mismatch;
1037 const char *symbol_white_list[20];
1038 void (*handler)(const char *modname, struct elf_info *elf,
1039 const struct sectioncheck* const mismatch,
1040 Elf_Rela *r, Elf_Sym *sym, const char *fromsec);
1041
1042 };
1043
1044 static void extable_mismatch_handler(const char *modname, struct elf_info *elf,
1045 const struct sectioncheck* const mismatch,
1046 Elf_Rela *r, Elf_Sym *sym,
1047 const char *fromsec);
1048
1049 static const struct sectioncheck sectioncheck[] = {
1050 /* Do not reference init/exit code/data from
1051 * normal code and data
1052 */
1053 {
1054 .fromsec = { TEXT_SECTIONS, NULL },
1055 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1056 .mismatch = TEXT_TO_ANY_INIT,
1057 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1058 },
1059 {
1060 .fromsec = { DATA_SECTIONS, NULL },
1061 .bad_tosec = { ALL_XXXINIT_SECTIONS, NULL },
1062 .mismatch = DATA_TO_ANY_INIT,
1063 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1064 },
1065 {
1066 .fromsec = { DATA_SECTIONS, NULL },
1067 .bad_tosec = { INIT_SECTIONS, NULL },
1068 .mismatch = DATA_TO_ANY_INIT,
1069 .symbol_white_list = {
1070 "*_template", "*_timer", "*_sht", "*_ops",
1071 "*_probe", "*_probe_one", "*_console", NULL
1072 },
1073 },
1074 {
1075 .fromsec = { TEXT_SECTIONS, NULL },
1076 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1077 .mismatch = TEXT_TO_ANY_EXIT,
1078 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1079 },
1080 {
1081 .fromsec = { DATA_SECTIONS, NULL },
1082 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1083 .mismatch = DATA_TO_ANY_EXIT,
1084 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1085 },
1086 /* Do not reference init code/data from meminit code/data */
1087 {
1088 .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
1089 .bad_tosec = { INIT_SECTIONS, NULL },
1090 .mismatch = XXXINIT_TO_SOME_INIT,
1091 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1092 },
1093 /* Do not reference exit code/data from memexit code/data */
1094 {
1095 .fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
1096 .bad_tosec = { EXIT_SECTIONS, NULL },
1097 .mismatch = XXXEXIT_TO_SOME_EXIT,
1098 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1099 },
1100 /* Do not use exit code/data from init code */
1101 {
1102 .fromsec = { ALL_INIT_SECTIONS, NULL },
1103 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1104 .mismatch = ANY_INIT_TO_ANY_EXIT,
1105 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1106 },
1107 /* Do not use init code/data from exit code */
1108 {
1109 .fromsec = { ALL_EXIT_SECTIONS, NULL },
1110 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1111 .mismatch = ANY_EXIT_TO_ANY_INIT,
1112 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1113 },
1114 {
1115 .fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
1116 .bad_tosec = { INIT_SECTIONS, NULL },
1117 .mismatch = ANY_INIT_TO_ANY_EXIT,
1118 .symbol_white_list = { NULL },
1119 },
1120 /* Do not export init/exit functions or data */
1121 {
1122 .fromsec = { "__ksymtab*", NULL },
1123 .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
1124 .mismatch = EXPORT_TO_INIT_EXIT,
1125 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1126 },
1127 {
1128 .fromsec = { "__ex_table", NULL },
1129 /* If you're adding any new black-listed sections in here, consider
1130 * adding a special 'printer' for them in scripts/check_extable.
1131 */
1132 .bad_tosec = { ".altinstr_replacement", NULL },
1133 .good_tosec = {ALL_TEXT_SECTIONS , NULL},
1134 .mismatch = EXTABLE_TO_NON_TEXT,
1135 .handler = extable_mismatch_handler,
1136 }
1137 };
1138
1139 static const struct sectioncheck *section_mismatch(
1140 const char *fromsec, const char *tosec)
1141 {
1142 int i;
1143 int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
1144 const struct sectioncheck *check = &sectioncheck[0];
1145
1146 /*
1147 * The target section could be the SHT_NUL section when we're
1148 * handling relocations to un-resolved symbols, trying to match it
1149 * doesn't make much sense and causes build failures on parisc
1150 * architectures.
1151 */
1152 if (*tosec == '\0')
1153 return NULL;
1154
1155 for (i = 0; i < elems; i++) {
1156 if (match(fromsec, check->fromsec)) {
1157 if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
1158 return check;
1159 if (check->good_tosec[0] && !match(tosec, check->good_tosec))
1160 return check;
1161 }
1162 check++;
1163 }
1164 return NULL;
1165 }
1166
1167 /**
1168 * Whitelist to allow certain references to pass with no warning.
1169 *
1170 * Pattern 1:
1171 * If a module parameter is declared __initdata and permissions=0
1172 * then this is legal despite the warning generated.
1173 * We cannot see value of permissions here, so just ignore
1174 * this pattern.
1175 * The pattern is identified by:
1176 * tosec = .init.data
1177 * fromsec = .data*
1178 * atsym =__param*
1179 *
1180 * Pattern 1a:
1181 * module_param_call() ops can refer to __init set function if permissions=0
1182 * The pattern is identified by:
1183 * tosec = .init.text
1184 * fromsec = .data*
1185 * atsym = __param_ops_*
1186 *
1187 * Pattern 2:
1188 * Many drivers utilise a *driver container with references to
1189 * add, remove, probe functions etc.
1190 * the pattern is identified by:
1191 * tosec = init or exit section
1192 * fromsec = data section
1193 * atsym = *driver, *_template, *_sht, *_ops, *_probe,
1194 * *probe_one, *_console, *_timer
1195 *
1196 * Pattern 3:
1197 * Whitelist all references from .head.text to any init section
1198 *
1199 * Pattern 4:
1200 * Some symbols belong to init section but still it is ok to reference
1201 * these from non-init sections as these symbols don't have any memory
1202 * allocated for them and symbol address and value are same. So even
1203 * if init section is freed, its ok to reference those symbols.
1204 * For ex. symbols marking the init section boundaries.
1205 * This pattern is identified by
1206 * refsymname = __init_begin, _sinittext, _einittext
1207 *
1208 * Pattern 5:
1209 * GCC may optimize static inlines when fed constant arg(s) resulting
1210 * in functions like cpumask_empty() -- generating an associated symbol
1211 * cpumask_empty.constprop.3 that appears in the audit. If the const that
1212 * is passed in comes from __init, like say nmi_ipi_mask, we get a
1213 * meaningless section warning. May need to add isra symbols too...
1214 * This pattern is identified by
1215 * tosec = init section
1216 * fromsec = text section
1217 * refsymname = *.constprop.*
1218 *
1219 * Pattern 6:
1220 * Hide section mismatch warnings for ELF local symbols. The goal
1221 * is to eliminate false positive modpost warnings caused by
1222 * compiler-generated ELF local symbol names such as ".LANCHOR1".
1223 * Autogenerated symbol names bypass modpost's "Pattern 2"
1224 * whitelisting, which relies on pattern-matching against symbol
1225 * names to work. (One situation where gcc can autogenerate ELF
1226 * local symbols is when "-fsection-anchors" is used.)
1227 **/
1228 static int secref_whitelist(const struct sectioncheck *mismatch,
1229 const char *fromsec, const char *fromsym,
1230 const char *tosec, const char *tosym)
1231 {
1232 /* Check for pattern 1 */
1233 if (match(tosec, init_data_sections) &&
1234 match(fromsec, data_sections) &&
1235 strstarts(fromsym, "__param"))
1236 return 0;
1237
1238 /* Check for pattern 1a */
1239 if (strcmp(tosec, ".init.text") == 0 &&
1240 match(fromsec, data_sections) &&
1241 strstarts(fromsym, "__param_ops_"))
1242 return 0;
1243
1244 /* Check for pattern 2 */
1245 if (match(tosec, init_exit_sections) &&
1246 match(fromsec, data_sections) &&
1247 match(fromsym, mismatch->symbol_white_list))
1248 return 0;
1249
1250 /* Check for pattern 3 */
1251 if (match(fromsec, head_sections) &&
1252 match(tosec, init_sections))
1253 return 0;
1254
1255 /* Check for pattern 4 */
1256 if (match(tosym, linker_symbols))
1257 return 0;
1258
1259 /* Check for pattern 5 */
1260 if (match(fromsec, text_sections) &&
1261 match(tosec, init_sections) &&
1262 match(fromsym, optim_symbols))
1263 return 0;
1264
1265 /* Check for pattern 6 */
1266 if (strstarts(fromsym, ".L"))
1267 return 0;
1268
1269 return 1;
1270 }
1271
1272 static inline int is_arm_mapping_symbol(const char *str)
1273 {
1274 return str[0] == '$' && strchr("axtd", str[1])
1275 && (str[2] == '\0' || str[2] == '.');
1276 }
1277
1278 /*
1279 * If there's no name there, ignore it; likewise, ignore it if it's
1280 * one of the magic symbols emitted used by current ARM tools.
1281 *
1282 * Otherwise if find_symbols_between() returns those symbols, they'll
1283 * fail the whitelist tests and cause lots of false alarms ... fixable
1284 * only by merging __exit and __init sections into __text, bloating
1285 * the kernel (which is especially evil on embedded platforms).
1286 */
1287 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1288 {
1289 const char *name = elf->strtab + sym->st_name;
1290
1291 if (!name || !strlen(name))
1292 return 0;
1293 return !is_arm_mapping_symbol(name);
1294 }
1295
1296 /**
1297 * Find symbol based on relocation record info.
1298 * In some cases the symbol supplied is a valid symbol so
1299 * return refsym. If st_name != 0 we assume this is a valid symbol.
1300 * In other cases the symbol needs to be looked up in the symbol table
1301 * based on section and address.
1302 * **/
1303 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
1304 Elf_Sym *relsym)
1305 {
1306 Elf_Sym *sym;
1307 Elf_Sym *near = NULL;
1308 Elf64_Sword distance = 20;
1309 Elf64_Sword d;
1310 unsigned int relsym_secindex;
1311
1312 if (relsym->st_name != 0)
1313 return relsym;
1314
1315 relsym_secindex = get_secindex(elf, relsym);
1316 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1317 if (get_secindex(elf, sym) != relsym_secindex)
1318 continue;
1319 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
1320 continue;
1321 if (!is_valid_name(elf, sym))
1322 continue;
1323 if (sym->st_value == addr)
1324 return sym;
1325 /* Find a symbol nearby - addr are maybe negative */
1326 d = sym->st_value - addr;
1327 if (d < 0)
1328 d = addr - sym->st_value;
1329 if (d < distance) {
1330 distance = d;
1331 near = sym;
1332 }
1333 }
1334 /* We need a close match */
1335 if (distance < 20)
1336 return near;
1337 else
1338 return NULL;
1339 }
1340
1341 /*
1342 * Find symbols before or equal addr and after addr - in the section sec.
1343 * If we find two symbols with equal offset prefer one with a valid name.
1344 * The ELF format may have a better way to detect what type of symbol
1345 * it is, but this works for now.
1346 **/
1347 static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1348 const char *sec)
1349 {
1350 Elf_Sym *sym;
1351 Elf_Sym *near = NULL;
1352 Elf_Addr distance = ~0;
1353
1354 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1355 const char *symsec;
1356
1357 if (is_shndx_special(sym->st_shndx))
1358 continue;
1359 symsec = sec_name(elf, get_secindex(elf, sym));
1360 if (strcmp(symsec, sec) != 0)
1361 continue;
1362 if (!is_valid_name(elf, sym))
1363 continue;
1364 if (sym->st_value <= addr) {
1365 if ((addr - sym->st_value) < distance) {
1366 distance = addr - sym->st_value;
1367 near = sym;
1368 } else if ((addr - sym->st_value) == distance) {
1369 near = sym;
1370 }
1371 }
1372 }
1373 return near;
1374 }
1375
1376 /*
1377 * Convert a section name to the function/data attribute
1378 * .init.text => __init
1379 * .memexitconst => __memconst
1380 * etc.
1381 *
1382 * The memory of returned value has been allocated on a heap. The user of this
1383 * method should free it after usage.
1384 */
1385 static char *sec2annotation(const char *s)
1386 {
1387 if (match(s, init_exit_sections)) {
1388 char *p = NOFAIL(malloc(20));
1389 char *r = p;
1390
1391 *p++ = '_';
1392 *p++ = '_';
1393 if (*s == '.')
1394 s++;
1395 while (*s && *s != '.')
1396 *p++ = *s++;
1397 *p = '\0';
1398 if (*s == '.')
1399 s++;
1400 if (strstr(s, "rodata") != NULL)
1401 strcat(p, "const ");
1402 else if (strstr(s, "data") != NULL)
1403 strcat(p, "data ");
1404 else
1405 strcat(p, " ");
1406 return r;
1407 } else {
1408 return NOFAIL(strdup(""));
1409 }
1410 }
1411
1412 static int is_function(Elf_Sym *sym)
1413 {
1414 if (sym)
1415 return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1416 else
1417 return -1;
1418 }
1419
1420 static void print_section_list(const char * const list[20])
1421 {
1422 const char *const *s = list;
1423
1424 while (*s) {
1425 fprintf(stderr, "%s", *s);
1426 s++;
1427 if (*s)
1428 fprintf(stderr, ", ");
1429 }
1430 fprintf(stderr, "\n");
1431 }
1432
1433 static inline void get_pretty_name(int is_func, const char** name, const char** name_p)
1434 {
1435 switch (is_func) {
1436 case 0: *name = "variable"; *name_p = ""; break;
1437 case 1: *name = "function"; *name_p = "()"; break;
1438 default: *name = "(unknown reference)"; *name_p = ""; break;
1439 }
1440 }
1441
1442 /*
1443 * Print a warning about a section mismatch.
1444 * Try to find symbols near it so user can find it.
1445 * Check whitelist before warning - it may be a false positive.
1446 */
1447 static void report_sec_mismatch(const char *modname,
1448 const struct sectioncheck *mismatch,
1449 const char *fromsec,
1450 unsigned long long fromaddr,
1451 const char *fromsym,
1452 int from_is_func,
1453 const char *tosec, const char *tosym,
1454 int to_is_func)
1455 {
1456 const char *from, *from_p;
1457 const char *to, *to_p;
1458 char *prl_from;
1459 char *prl_to;
1460
1461 sec_mismatch_count++;
1462
1463 get_pretty_name(from_is_func, &from, &from_p);
1464 get_pretty_name(to_is_func, &to, &to_p);
1465
1466 warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1467 "to the %s %s:%s%s\n",
1468 modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1469 tosym, to_p);
1470
1471 switch (mismatch->mismatch) {
1472 case TEXT_TO_ANY_INIT:
1473 prl_from = sec2annotation(fromsec);
1474 prl_to = sec2annotation(tosec);
1475 fprintf(stderr,
1476 "The function %s%s() references\n"
1477 "the %s %s%s%s.\n"
1478 "This is often because %s lacks a %s\n"
1479 "annotation or the annotation of %s is wrong.\n",
1480 prl_from, fromsym,
1481 to, prl_to, tosym, to_p,
1482 fromsym, prl_to, tosym);
1483 free(prl_from);
1484 free(prl_to);
1485 break;
1486 case DATA_TO_ANY_INIT: {
1487 prl_to = sec2annotation(tosec);
1488 fprintf(stderr,
1489 "The variable %s references\n"
1490 "the %s %s%s%s\n"
1491 "If the reference is valid then annotate the\n"
1492 "variable with __init* or __refdata (see linux/init.h) "
1493 "or name the variable:\n",
1494 fromsym, to, prl_to, tosym, to_p);
1495 print_section_list(mismatch->symbol_white_list);
1496 free(prl_to);
1497 break;
1498 }
1499 case TEXT_TO_ANY_EXIT:
1500 prl_to = sec2annotation(tosec);
1501 fprintf(stderr,
1502 "The function %s() references a %s in an exit section.\n"
1503 "Often the %s %s%s has valid usage outside the exit section\n"
1504 "and the fix is to remove the %sannotation of %s.\n",
1505 fromsym, to, to, tosym, to_p, prl_to, tosym);
1506 free(prl_to);
1507 break;
1508 case DATA_TO_ANY_EXIT: {
1509 prl_to = sec2annotation(tosec);
1510 fprintf(stderr,
1511 "The variable %s references\n"
1512 "the %s %s%s%s\n"
1513 "If the reference is valid then annotate the\n"
1514 "variable with __exit* (see linux/init.h) or "
1515 "name the variable:\n",
1516 fromsym, to, prl_to, tosym, to_p);
1517 print_section_list(mismatch->symbol_white_list);
1518 free(prl_to);
1519 break;
1520 }
1521 case XXXINIT_TO_SOME_INIT:
1522 case XXXEXIT_TO_SOME_EXIT:
1523 prl_from = sec2annotation(fromsec);
1524 prl_to = sec2annotation(tosec);
1525 fprintf(stderr,
1526 "The %s %s%s%s references\n"
1527 "a %s %s%s%s.\n"
1528 "If %s is only used by %s then\n"
1529 "annotate %s with a matching annotation.\n",
1530 from, prl_from, fromsym, from_p,
1531 to, prl_to, tosym, to_p,
1532 tosym, fromsym, tosym);
1533 free(prl_from);
1534 free(prl_to);
1535 break;
1536 case ANY_INIT_TO_ANY_EXIT:
1537 prl_from = sec2annotation(fromsec);
1538 prl_to = sec2annotation(tosec);
1539 fprintf(stderr,
1540 "The %s %s%s%s references\n"
1541 "a %s %s%s%s.\n"
1542 "This is often seen when error handling "
1543 "in the init function\n"
1544 "uses functionality in the exit path.\n"
1545 "The fix is often to remove the %sannotation of\n"
1546 "%s%s so it may be used outside an exit section.\n",
1547 from, prl_from, fromsym, from_p,
1548 to, prl_to, tosym, to_p,
1549 prl_to, tosym, to_p);
1550 free(prl_from);
1551 free(prl_to);
1552 break;
1553 case ANY_EXIT_TO_ANY_INIT:
1554 prl_from = sec2annotation(fromsec);
1555 prl_to = sec2annotation(tosec);
1556 fprintf(stderr,
1557 "The %s %s%s%s references\n"
1558 "a %s %s%s%s.\n"
1559 "This is often seen when error handling "
1560 "in the exit function\n"
1561 "uses functionality in the init path.\n"
1562 "The fix is often to remove the %sannotation of\n"
1563 "%s%s so it may be used outside an init section.\n",
1564 from, prl_from, fromsym, from_p,
1565 to, prl_to, tosym, to_p,
1566 prl_to, tosym, to_p);
1567 free(prl_from);
1568 free(prl_to);
1569 break;
1570 case EXPORT_TO_INIT_EXIT:
1571 prl_to = sec2annotation(tosec);
1572 fprintf(stderr,
1573 "The symbol %s is exported and annotated %s\n"
1574 "Fix this by removing the %sannotation of %s "
1575 "or drop the export.\n",
1576 tosym, prl_to, prl_to, tosym);
1577 free(prl_to);
1578 break;
1579 case EXTABLE_TO_NON_TEXT:
1580 fatal("There's a special handler for this mismatch type, "
1581 "we should never get here.");
1582 break;
1583 }
1584 fprintf(stderr, "\n");
1585 }
1586
1587 static void default_mismatch_handler(const char *modname, struct elf_info *elf,
1588 const struct sectioncheck* const mismatch,
1589 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1590 {
1591 const char *tosec;
1592 Elf_Sym *to;
1593 Elf_Sym *from;
1594 const char *tosym;
1595 const char *fromsym;
1596
1597 from = find_elf_symbol2(elf, r->r_offset, fromsec);
1598 fromsym = sym_name(elf, from);
1599
1600 if (strstarts(fromsym, "reference___initcall"))
1601 return;
1602
1603 tosec = sec_name(elf, get_secindex(elf, sym));
1604 to = find_elf_symbol(elf, r->r_addend, sym);
1605 tosym = sym_name(elf, to);
1606
1607 /* check whitelist - we may ignore it */
1608 if (secref_whitelist(mismatch,
1609 fromsec, fromsym, tosec, tosym)) {
1610 report_sec_mismatch(modname, mismatch,
1611 fromsec, r->r_offset, fromsym,
1612 is_function(from), tosec, tosym,
1613 is_function(to));
1614 }
1615 }
1616
1617 static int is_executable_section(struct elf_info* elf, unsigned int section_index)
1618 {
1619 if (section_index > elf->num_sections)
1620 fatal("section_index is outside elf->num_sections!\n");
1621
1622 return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR);
1623 }
1624
1625 /*
1626 * We rely on a gross hack in section_rel[a]() calling find_extable_entry_size()
1627 * to know the sizeof(struct exception_table_entry) for the target architecture.
1628 */
1629 static unsigned int extable_entry_size = 0;
1630 static void find_extable_entry_size(const char* const sec, const Elf_Rela* r)
1631 {
1632 /*
1633 * If we're currently checking the second relocation within __ex_table,
1634 * that relocation offset tells us the offsetof(struct
1635 * exception_table_entry, fixup) which is equal to sizeof(struct
1636 * exception_table_entry) divided by two. We use that to our advantage
1637 * since there's no portable way to get that size as every architecture
1638 * seems to go with different sized types. Not pretty but better than
1639 * hard-coding the size for every architecture..
1640 */
1641 if (!extable_entry_size)
1642 extable_entry_size = r->r_offset * 2;
1643 }
1644
1645 static inline bool is_extable_fault_address(Elf_Rela *r)
1646 {
1647 /*
1648 * extable_entry_size is only discovered after we've handled the
1649 * _second_ relocation in __ex_table, so only abort when we're not
1650 * handling the first reloc and extable_entry_size is zero.
1651 */
1652 if (r->r_offset && extable_entry_size == 0)
1653 fatal("extable_entry size hasn't been discovered!\n");
1654
1655 return ((r->r_offset == 0) ||
1656 (r->r_offset % extable_entry_size == 0));
1657 }
1658
1659 #define is_second_extable_reloc(Start, Cur, Sec) \
1660 (((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0))
1661
1662 static void report_extable_warnings(const char* modname, struct elf_info* elf,
1663 const struct sectioncheck* const mismatch,
1664 Elf_Rela* r, Elf_Sym* sym,
1665 const char* fromsec, const char* tosec)
1666 {
1667 Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec);
1668 const char* fromsym_name = sym_name(elf, fromsym);
1669 Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym);
1670 const char* tosym_name = sym_name(elf, tosym);
1671 const char* from_pretty_name;
1672 const char* from_pretty_name_p;
1673 const char* to_pretty_name;
1674 const char* to_pretty_name_p;
1675
1676 get_pretty_name(is_function(fromsym),
1677 &from_pretty_name, &from_pretty_name_p);
1678 get_pretty_name(is_function(tosym),
1679 &to_pretty_name, &to_pretty_name_p);
1680
1681 warn("%s(%s+0x%lx): Section mismatch in reference"
1682 " from the %s %s%s to the %s %s:%s%s\n",
1683 modname, fromsec, (long)r->r_offset, from_pretty_name,
1684 fromsym_name, from_pretty_name_p,
1685 to_pretty_name, tosec, tosym_name, to_pretty_name_p);
1686
1687 if (!match(tosec, mismatch->bad_tosec) &&
1688 is_executable_section(elf, get_secindex(elf, sym)))
1689 fprintf(stderr,
1690 "The relocation at %s+0x%lx references\n"
1691 "section \"%s\" which is not in the list of\n"
1692 "authorized sections. If you're adding a new section\n"
1693 "and/or if this reference is valid, add \"%s\" to the\n"
1694 "list of authorized sections to jump to on fault.\n"
1695 "This can be achieved by adding \"%s\" to \n"
1696 "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
1697 fromsec, (long)r->r_offset, tosec, tosec, tosec);
1698 }
1699
1700 static void extable_mismatch_handler(const char* modname, struct elf_info *elf,
1701 const struct sectioncheck* const mismatch,
1702 Elf_Rela* r, Elf_Sym* sym,
1703 const char *fromsec)
1704 {
1705 const char* tosec = sec_name(elf, get_secindex(elf, sym));
1706
1707 sec_mismatch_count++;
1708
1709 report_extable_warnings(modname, elf, mismatch, r, sym, fromsec, tosec);
1710
1711 if (match(tosec, mismatch->bad_tosec))
1712 fatal("The relocation at %s+0x%lx references\n"
1713 "section \"%s\" which is black-listed.\n"
1714 "Something is seriously wrong and should be fixed.\n"
1715 "You might get more information about where this is\n"
1716 "coming from by using scripts/check_extable.sh %s\n",
1717 fromsec, (long)r->r_offset, tosec, modname);
1718 else if (!is_executable_section(elf, get_secindex(elf, sym))) {
1719 if (is_extable_fault_address(r))
1720 fatal("The relocation at %s+0x%lx references\n"
1721 "section \"%s\" which is not executable, IOW\n"
1722 "it is not possible for the kernel to fault\n"
1723 "at that address. Something is seriously wrong\n"
1724 "and should be fixed.\n",
1725 fromsec, (long)r->r_offset, tosec);
1726 else
1727 fatal("The relocation at %s+0x%lx references\n"
1728 "section \"%s\" which is not executable, IOW\n"
1729 "the kernel will fault if it ever tries to\n"
1730 "jump to it. Something is seriously wrong\n"
1731 "and should be fixed.\n",
1732 fromsec, (long)r->r_offset, tosec);
1733 }
1734 }
1735
1736 static void check_section_mismatch(const char *modname, struct elf_info *elf,
1737 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1738 {
1739 const char *tosec = sec_name(elf, get_secindex(elf, sym));
1740 const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec);
1741
1742 if (mismatch) {
1743 if (mismatch->handler)
1744 mismatch->handler(modname, elf, mismatch,
1745 r, sym, fromsec);
1746 else
1747 default_mismatch_handler(modname, elf, mismatch,
1748 r, sym, fromsec);
1749 }
1750 }
1751
1752 static unsigned int *reloc_location(struct elf_info *elf,
1753 Elf_Shdr *sechdr, Elf_Rela *r)
1754 {
1755 Elf_Shdr *sechdrs = elf->sechdrs;
1756 int section = sechdr->sh_info;
1757
1758 return (void *)elf->hdr + sechdrs[section].sh_offset +
1759 r->r_offset;
1760 }
1761
1762 static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1763 {
1764 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1765 unsigned int *location = reloc_location(elf, sechdr, r);
1766
1767 switch (r_typ) {
1768 case R_386_32:
1769 r->r_addend = TO_NATIVE(*location);
1770 break;
1771 case R_386_PC32:
1772 r->r_addend = TO_NATIVE(*location) + 4;
1773 /* For CONFIG_RELOCATABLE=y */
1774 if (elf->hdr->e_type == ET_EXEC)
1775 r->r_addend += r->r_offset;
1776 break;
1777 }
1778 return 0;
1779 }
1780
1781 #ifndef R_ARM_CALL
1782 #define R_ARM_CALL 28
1783 #endif
1784 #ifndef R_ARM_JUMP24
1785 #define R_ARM_JUMP24 29
1786 #endif
1787
1788 #ifndef R_ARM_THM_CALL
1789 #define R_ARM_THM_CALL 10
1790 #endif
1791 #ifndef R_ARM_THM_JUMP24
1792 #define R_ARM_THM_JUMP24 30
1793 #endif
1794 #ifndef R_ARM_THM_JUMP19
1795 #define R_ARM_THM_JUMP19 51
1796 #endif
1797
1798 static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1799 {
1800 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1801
1802 switch (r_typ) {
1803 case R_ARM_ABS32:
1804 /* From ARM ABI: (S + A) | T */
1805 r->r_addend = (int)(long)
1806 (elf->symtab_start + ELF_R_SYM(r->r_info));
1807 break;
1808 case R_ARM_PC24:
1809 case R_ARM_CALL:
1810 case R_ARM_JUMP24:
1811 case R_ARM_THM_CALL:
1812 case R_ARM_THM_JUMP24:
1813 case R_ARM_THM_JUMP19:
1814 /* From ARM ABI: ((S + A) | T) - P */
1815 r->r_addend = (int)(long)(elf->hdr +
1816 sechdr->sh_offset +
1817 (r->r_offset - sechdr->sh_addr));
1818 break;
1819 default:
1820 return 1;
1821 }
1822 return 0;
1823 }
1824
1825 static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1826 {
1827 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1828 unsigned int *location = reloc_location(elf, sechdr, r);
1829 unsigned int inst;
1830
1831 if (r_typ == R_MIPS_HI16)
1832 return 1; /* skip this */
1833 inst = TO_NATIVE(*location);
1834 switch (r_typ) {
1835 case R_MIPS_LO16:
1836 r->r_addend = inst & 0xffff;
1837 break;
1838 case R_MIPS_26:
1839 r->r_addend = (inst & 0x03ffffff) << 2;
1840 break;
1841 case R_MIPS_32:
1842 r->r_addend = inst;
1843 break;
1844 }
1845 return 0;
1846 }
1847
1848 static void section_rela(const char *modname, struct elf_info *elf,
1849 Elf_Shdr *sechdr)
1850 {
1851 Elf_Sym *sym;
1852 Elf_Rela *rela;
1853 Elf_Rela r;
1854 unsigned int r_sym;
1855 const char *fromsec;
1856
1857 Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1858 Elf_Rela *stop = (void *)start + sechdr->sh_size;
1859
1860 fromsec = sech_name(elf, sechdr);
1861 fromsec += strlen(".rela");
1862 /* if from section (name) is know good then skip it */
1863 if (match(fromsec, section_white_list))
1864 return;
1865
1866 for (rela = start; rela < stop; rela++) {
1867 r.r_offset = TO_NATIVE(rela->r_offset);
1868 #if KERNEL_ELFCLASS == ELFCLASS64
1869 if (elf->hdr->e_machine == EM_MIPS) {
1870 unsigned int r_typ;
1871 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1872 r_sym = TO_NATIVE(r_sym);
1873 r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1874 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1875 } else {
1876 r.r_info = TO_NATIVE(rela->r_info);
1877 r_sym = ELF_R_SYM(r.r_info);
1878 }
1879 #else
1880 r.r_info = TO_NATIVE(rela->r_info);
1881 r_sym = ELF_R_SYM(r.r_info);
1882 #endif
1883 r.r_addend = TO_NATIVE(rela->r_addend);
1884 sym = elf->symtab_start + r_sym;
1885 /* Skip special sections */
1886 if (is_shndx_special(sym->st_shndx))
1887 continue;
1888 if (is_second_extable_reloc(start, rela, fromsec))
1889 find_extable_entry_size(fromsec, &r);
1890 check_section_mismatch(modname, elf, &r, sym, fromsec);
1891 }
1892 }
1893
1894 static void section_rel(const char *modname, struct elf_info *elf,
1895 Elf_Shdr *sechdr)
1896 {
1897 Elf_Sym *sym;
1898 Elf_Rel *rel;
1899 Elf_Rela r;
1900 unsigned int r_sym;
1901 const char *fromsec;
1902
1903 Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1904 Elf_Rel *stop = (void *)start + sechdr->sh_size;
1905
1906 fromsec = sech_name(elf, sechdr);
1907 fromsec += strlen(".rel");
1908 /* if from section (name) is know good then skip it */
1909 if (match(fromsec, section_white_list))
1910 return;
1911
1912 for (rel = start; rel < stop; rel++) {
1913 r.r_offset = TO_NATIVE(rel->r_offset);
1914 #if KERNEL_ELFCLASS == ELFCLASS64
1915 if (elf->hdr->e_machine == EM_MIPS) {
1916 unsigned int r_typ;
1917 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1918 r_sym = TO_NATIVE(r_sym);
1919 r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1920 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1921 } else {
1922 r.r_info = TO_NATIVE(rel->r_info);
1923 r_sym = ELF_R_SYM(r.r_info);
1924 }
1925 #else
1926 r.r_info = TO_NATIVE(rel->r_info);
1927 r_sym = ELF_R_SYM(r.r_info);
1928 #endif
1929 r.r_addend = 0;
1930 switch (elf->hdr->e_machine) {
1931 case EM_386:
1932 if (addend_386_rel(elf, sechdr, &r))
1933 continue;
1934 break;
1935 case EM_ARM:
1936 if (addend_arm_rel(elf, sechdr, &r))
1937 continue;
1938 break;
1939 case EM_MIPS:
1940 if (addend_mips_rel(elf, sechdr, &r))
1941 continue;
1942 break;
1943 }
1944 sym = elf->symtab_start + r_sym;
1945 /* Skip special sections */
1946 if (is_shndx_special(sym->st_shndx))
1947 continue;
1948 if (is_second_extable_reloc(start, rel, fromsec))
1949 find_extable_entry_size(fromsec, &r);
1950 check_section_mismatch(modname, elf, &r, sym, fromsec);
1951 }
1952 }
1953
1954 /**
1955 * A module includes a number of sections that are discarded
1956 * either when loaded or when used as built-in.
1957 * For loaded modules all functions marked __init and all data
1958 * marked __initdata will be discarded when the module has been initialized.
1959 * Likewise for modules used built-in the sections marked __exit
1960 * are discarded because __exit marked function are supposed to be called
1961 * only when a module is unloaded which never happens for built-in modules.
1962 * The check_sec_ref() function traverses all relocation records
1963 * to find all references to a section that reference a section that will
1964 * be discarded and warns about it.
1965 **/
1966 static void check_sec_ref(struct module *mod, const char *modname,
1967 struct elf_info *elf)
1968 {
1969 int i;
1970 Elf_Shdr *sechdrs = elf->sechdrs;
1971
1972 /* Walk through all sections */
1973 for (i = 0; i < elf->num_sections; i++) {
1974 check_section(modname, elf, &elf->sechdrs[i]);
1975 /* We want to process only relocation sections and not .init */
1976 if (sechdrs[i].sh_type == SHT_RELA)
1977 section_rela(modname, elf, &elf->sechdrs[i]);
1978 else if (sechdrs[i].sh_type == SHT_REL)
1979 section_rel(modname, elf, &elf->sechdrs[i]);
1980 }
1981 }
1982
1983 static char *remove_dot(char *s)
1984 {
1985 size_t n = strcspn(s, ".");
1986
1987 if (n && s[n]) {
1988 size_t m = strspn(s + n + 1, "0123456789");
1989 if (m && (s[n + m] == '.' || s[n + m] == 0))
1990 s[n] = 0;
1991 }
1992 return s;
1993 }
1994
1995 static void read_symbols(const char *modname)
1996 {
1997 const char *symname;
1998 char *version;
1999 char *license;
2000 char *namespace;
2001 struct module *mod;
2002 struct elf_info info = { };
2003 Elf_Sym *sym;
2004
2005 if (!parse_elf(&info, modname))
2006 return;
2007
2008 mod = new_module(modname);
2009
2010 /* When there's no vmlinux, don't print warnings about
2011 * unresolved symbols (since there'll be too many ;) */
2012 if (is_vmlinux(modname)) {
2013 have_vmlinux = 1;
2014 mod->skip = 1;
2015 }
2016
2017 license = get_modinfo(&info, "license");
2018 if (!license && !is_vmlinux(modname))
2019 warn("missing MODULE_LICENSE() in %s\n"
2020 "see include/linux/module.h for "
2021 "more information\n", modname);
2022 while (license) {
2023 if (license_is_gpl_compatible(license))
2024 mod->gpl_compatible = 1;
2025 else {
2026 mod->gpl_compatible = 0;
2027 break;
2028 }
2029 license = get_next_modinfo(&info, "license", license);
2030 }
2031
2032 namespace = get_modinfo(&info, "import_ns");
2033 while (namespace) {
2034 add_namespace(&mod->imported_namespaces, namespace);
2035 namespace = get_next_modinfo(&info, "import_ns", namespace);
2036 }
2037
2038 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
2039 symname = remove_dot(info.strtab + sym->st_name);
2040
2041 handle_symbol(mod, &info, sym, symname);
2042 handle_moddevtable(mod, &info, sym, symname);
2043 }
2044
2045 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
2046 symname = remove_dot(info.strtab + sym->st_name);
2047
2048 /* Apply symbol namespaces from __kstrtabns_<symbol> entries. */
2049 if (strstarts(symname, "__kstrtabns_"))
2050 sym_update_namespace(symname + strlen("__kstrtabns_"),
2051 namespace_from_kstrtabns(&info,
2052 sym));
2053
2054 if (strstarts(symname, "__crc_"))
2055 handle_modversion(mod, &info, sym,
2056 symname + strlen("__crc_"));
2057 }
2058
2059 // check for static EXPORT_SYMBOL_* functions && global vars
2060 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
2061 unsigned char bind = ELF_ST_BIND(sym->st_info);
2062
2063 if (bind == STB_GLOBAL || bind == STB_WEAK) {
2064 struct symbol *s =
2065 find_symbol(remove_dot(info.strtab +
2066 sym->st_name));
2067
2068 if (s)
2069 s->is_static = 0;
2070 }
2071 }
2072
2073 if (!is_vmlinux(modname) || vmlinux_section_warnings)
2074 check_sec_ref(mod, modname, &info);
2075
2076 version = get_modinfo(&info, "version");
2077 if (version)
2078 maybe_frob_rcs_version(modname, version, info.modinfo,
2079 version - (char *)info.hdr);
2080 if (version || (all_versions && !is_vmlinux(modname)))
2081 get_src_version(modname, mod->srcversion,
2082 sizeof(mod->srcversion)-1);
2083
2084 parse_elf_finish(&info);
2085
2086 /* Our trick to get versioning for module struct etc. - it's
2087 * never passed as an argument to an exported function, so
2088 * the automatic versioning doesn't pick it up, but it's really
2089 * important anyhow */
2090 if (modversions)
2091 mod->unres = alloc_symbol("module_layout", 0, mod->unres);
2092 }
2093
2094 static void read_symbols_from_files(const char *filename)
2095 {
2096 FILE *in = stdin;
2097 char fname[PATH_MAX];
2098
2099 if (strcmp(filename, "-") != 0) {
2100 in = fopen(filename, "r");
2101 if (!in)
2102 fatal("Can't open filenames file %s: %m", filename);
2103 }
2104
2105 while (fgets(fname, PATH_MAX, in) != NULL) {
2106 if (strends(fname, "\n"))
2107 fname[strlen(fname)-1] = '\0';
2108 read_symbols(fname);
2109 }
2110
2111 if (in != stdin)
2112 fclose(in);
2113 }
2114
2115 #define SZ 500
2116
2117 /* We first write the generated file into memory using the
2118 * following helper, then compare to the file on disk and
2119 * only update the later if anything changed */
2120
2121 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
2122 const char *fmt, ...)
2123 {
2124 char tmp[SZ];
2125 int len;
2126 va_list ap;
2127
2128 va_start(ap, fmt);
2129 len = vsnprintf(tmp, SZ, fmt, ap);
2130 buf_write(buf, tmp, len);
2131 va_end(ap);
2132 }
2133
2134 void buf_write(struct buffer *buf, const char *s, int len)
2135 {
2136 if (buf->size - buf->pos < len) {
2137 buf->size += len + SZ;
2138 buf->p = NOFAIL(realloc(buf->p, buf->size));
2139 }
2140 strncpy(buf->p + buf->pos, s, len);
2141 buf->pos += len;
2142 }
2143
2144 static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
2145 {
2146 const char *e = is_vmlinux(m) ?"":".ko";
2147
2148 switch (exp) {
2149 case export_gpl:
2150 fatal("GPL-incompatible module %s%s "
2151 "uses GPL-only symbol '%s'\n", m, e, s);
2152 break;
2153 case export_unused_gpl:
2154 fatal("GPL-incompatible module %s%s "
2155 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
2156 break;
2157 case export_gpl_future:
2158 warn("GPL-incompatible module %s%s "
2159 "uses future GPL-only symbol '%s'\n", m, e, s);
2160 break;
2161 case export_plain:
2162 case export_unused:
2163 case export_unknown:
2164 /* ignore */
2165 break;
2166 }
2167 }
2168
2169 static void check_for_unused(enum export exp, const char *m, const char *s)
2170 {
2171 const char *e = is_vmlinux(m) ?"":".ko";
2172
2173 switch (exp) {
2174 case export_unused:
2175 case export_unused_gpl:
2176 warn("module %s%s "
2177 "uses symbol '%s' marked UNUSED\n", m, e, s);
2178 break;
2179 default:
2180 /* ignore */
2181 break;
2182 }
2183 }
2184
2185 static int check_exports(struct module *mod)
2186 {
2187 struct symbol *s, *exp;
2188 int err = 0;
2189
2190 for (s = mod->unres; s; s = s->next) {
2191 const char *basename;
2192 exp = find_symbol(s->name);
2193 if (!exp || exp->module == mod) {
2194 if (have_vmlinux && !s->weak) {
2195 modpost_log(warn_unresolved ? LOG_WARN : LOG_ERROR,
2196 "\"%s\" [%s.ko] undefined!\n",
2197 s->name, mod->name);
2198 if (!warn_unresolved)
2199 err = 1;
2200 }
2201 continue;
2202 }
2203 basename = strrchr(mod->name, '/');
2204 if (basename)
2205 basename++;
2206 else
2207 basename = mod->name;
2208
2209 if (exp->namespace &&
2210 !module_imports_namespace(mod, exp->namespace)) {
2211 modpost_log(allow_missing_ns_imports ? LOG_WARN : LOG_ERROR,
2212 "module %s uses symbol %s from namespace %s, but does not import it.\n",
2213 basename, exp->name, exp->namespace);
2214 if (!allow_missing_ns_imports)
2215 err = 1;
2216 add_namespace(&mod->missing_namespaces, exp->namespace);
2217 }
2218
2219 if (!mod->gpl_compatible)
2220 check_for_gpl_usage(exp->export, basename, exp->name);
2221 check_for_unused(exp->export, basename, exp->name);
2222 }
2223
2224 return err;
2225 }
2226
2227 static int check_modname_len(struct module *mod)
2228 {
2229 const char *mod_name;
2230
2231 mod_name = strrchr(mod->name, '/');
2232 if (mod_name == NULL)
2233 mod_name = mod->name;
2234 else
2235 mod_name++;
2236 if (strlen(mod_name) >= MODULE_NAME_LEN) {
2237 merror("module name is too long [%s.ko]\n", mod->name);
2238 return 1;
2239 }
2240
2241 return 0;
2242 }
2243
2244 /**
2245 * Header for the generated file
2246 **/
2247 static void add_header(struct buffer *b, struct module *mod)
2248 {
2249 buf_printf(b, "#include <linux/module.h>\n");
2250 /*
2251 * Include build-salt.h after module.h in order to
2252 * inherit the definitions.
2253 */
2254 buf_printf(b, "#include <linux/build-salt.h>\n");
2255 buf_printf(b, "#include <linux/vermagic.h>\n");
2256 buf_printf(b, "#include <linux/compiler.h>\n");
2257 buf_printf(b, "\n");
2258 buf_printf(b, "BUILD_SALT;\n");
2259 buf_printf(b, "\n");
2260 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
2261 buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n");
2262 buf_printf(b, "\n");
2263 buf_printf(b, "__visible struct module __this_module\n");
2264 buf_printf(b, "__section(.gnu.linkonce.this_module) = {\n");
2265 buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
2266 if (mod->has_init)
2267 buf_printf(b, "\t.init = init_module,\n");
2268 if (mod->has_cleanup)
2269 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
2270 "\t.exit = cleanup_module,\n"
2271 "#endif\n");
2272 buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
2273 buf_printf(b, "};\n");
2274 }
2275
2276 static void add_intree_flag(struct buffer *b, int is_intree)
2277 {
2278 if (is_intree)
2279 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
2280 }
2281
2282 /* Cannot check for assembler */
2283 static void add_retpoline(struct buffer *b)
2284 {
2285 buf_printf(b, "\n#ifdef CONFIG_RETPOLINE\n");
2286 buf_printf(b, "MODULE_INFO(retpoline, \"Y\");\n");
2287 buf_printf(b, "#endif\n");
2288 }
2289
2290 static void add_staging_flag(struct buffer *b, const char *name)
2291 {
2292 if (strstarts(name, "drivers/staging"))
2293 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
2294 }
2295
2296 /**
2297 * Record CRCs for unresolved symbols
2298 **/
2299 static int add_versions(struct buffer *b, struct module *mod)
2300 {
2301 struct symbol *s, *exp;
2302 int err = 0;
2303
2304 for (s = mod->unres; s; s = s->next) {
2305 exp = find_symbol(s->name);
2306 if (!exp || exp->module == mod)
2307 continue;
2308 s->module = exp->module;
2309 s->crc_valid = exp->crc_valid;
2310 s->crc = exp->crc;
2311 }
2312
2313 if (!modversions)
2314 return err;
2315
2316 buf_printf(b, "\n");
2317 buf_printf(b, "static const struct modversion_info ____versions[]\n");
2318 buf_printf(b, "__used __section(__versions) = {\n");
2319
2320 for (s = mod->unres; s; s = s->next) {
2321 if (!s->module)
2322 continue;
2323 if (!s->crc_valid) {
2324 warn("\"%s\" [%s.ko] has no CRC!\n",
2325 s->name, mod->name);
2326 continue;
2327 }
2328 if (strlen(s->name) >= MODULE_NAME_LEN) {
2329 merror("too long symbol \"%s\" [%s.ko]\n",
2330 s->name, mod->name);
2331 err = 1;
2332 break;
2333 }
2334 buf_printf(b, "\t{ %#8x, \"%s\" },\n",
2335 s->crc, s->name);
2336 }
2337
2338 buf_printf(b, "};\n");
2339
2340 return err;
2341 }
2342
2343 static void add_depends(struct buffer *b, struct module *mod)
2344 {
2345 struct symbol *s;
2346 int first = 1;
2347
2348 /* Clear ->seen flag of modules that own symbols needed by this. */
2349 for (s = mod->unres; s; s = s->next)
2350 if (s->module)
2351 s->module->seen = is_vmlinux(s->module->name);
2352
2353 buf_printf(b, "\n");
2354 buf_printf(b, "MODULE_INFO(depends, \"");
2355 for (s = mod->unres; s; s = s->next) {
2356 const char *p;
2357 if (!s->module)
2358 continue;
2359
2360 if (s->module->seen)
2361 continue;
2362
2363 s->module->seen = 1;
2364 p = strrchr(s->module->name, '/');
2365 if (p)
2366 p++;
2367 else
2368 p = s->module->name;
2369 buf_printf(b, "%s%s", first ? "" : ",", p);
2370 first = 0;
2371 }
2372 buf_printf(b, "\");\n");
2373 }
2374
2375 static void add_srcversion(struct buffer *b, struct module *mod)
2376 {
2377 if (mod->srcversion[0]) {
2378 buf_printf(b, "\n");
2379 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
2380 mod->srcversion);
2381 }
2382 }
2383
2384 static void write_if_changed(struct buffer *b, const char *fname)
2385 {
2386 char *tmp;
2387 FILE *file;
2388 struct stat st;
2389
2390 file = fopen(fname, "r");
2391 if (!file)
2392 goto write;
2393
2394 if (fstat(fileno(file), &st) < 0)
2395 goto close_write;
2396
2397 if (st.st_size != b->pos)
2398 goto close_write;
2399
2400 tmp = NOFAIL(malloc(b->pos));
2401 if (fread(tmp, 1, b->pos, file) != b->pos)
2402 goto free_write;
2403
2404 if (memcmp(tmp, b->p, b->pos) != 0)
2405 goto free_write;
2406
2407 free(tmp);
2408 fclose(file);
2409 return;
2410
2411 free_write:
2412 free(tmp);
2413 close_write:
2414 fclose(file);
2415 write:
2416 file = fopen(fname, "w");
2417 if (!file) {
2418 perror(fname);
2419 exit(1);
2420 }
2421 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
2422 perror(fname);
2423 exit(1);
2424 }
2425 fclose(file);
2426 }
2427
2428 /* parse Module.symvers file. line format:
2429 * 0x12345678<tab>symbol<tab>module<tab>export<tab>namespace
2430 **/
2431 static void read_dump(const char *fname, unsigned int kernel)
2432 {
2433 unsigned long size, pos = 0;
2434 void *file = grab_file(fname, &size);
2435 char *line;
2436
2437 if (!file)
2438 /* No symbol versions, silently ignore */
2439 return;
2440
2441 while ((line = get_next_line(&pos, file, size))) {
2442 char *symname, *namespace, *modname, *d, *export;
2443 unsigned int crc;
2444 struct module *mod;
2445 struct symbol *s;
2446
2447 if (!(symname = strchr(line, '\t')))
2448 goto fail;
2449 *symname++ = '\0';
2450 if (!(modname = strchr(symname, '\t')))
2451 goto fail;
2452 *modname++ = '\0';
2453 if (!(export = strchr(modname, '\t')))
2454 goto fail;
2455 *export++ = '\0';
2456 if (!(namespace = strchr(export, '\t')))
2457 goto fail;
2458 *namespace++ = '\0';
2459
2460 crc = strtoul(line, &d, 16);
2461 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2462 goto fail;
2463 mod = find_module(modname);
2464 if (!mod) {
2465 if (is_vmlinux(modname))
2466 have_vmlinux = 1;
2467 mod = new_module(modname);
2468 mod->skip = 1;
2469 }
2470 s = sym_add_exported(symname, mod, export_no(export));
2471 s->kernel = kernel;
2472 s->is_static = 0;
2473 sym_set_crc(symname, crc);
2474 sym_update_namespace(symname, namespace);
2475 }
2476 release_file(file, size);
2477 return;
2478 fail:
2479 release_file(file, size);
2480 fatal("parse error in symbol dump file\n");
2481 }
2482
2483 /* For normal builds always dump all symbols.
2484 * For external modules only dump symbols
2485 * that are not read from kernel Module.symvers.
2486 **/
2487 static int dump_sym(struct symbol *sym)
2488 {
2489 if (!external_module)
2490 return 1;
2491 if (sym->vmlinux || sym->kernel)
2492 return 0;
2493 return 1;
2494 }
2495
2496 static void write_dump(const char *fname)
2497 {
2498 struct buffer buf = { };
2499 struct symbol *symbol;
2500 const char *namespace;
2501 int n;
2502
2503 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
2504 symbol = symbolhash[n];
2505 while (symbol) {
2506 if (dump_sym(symbol)) {
2507 namespace = symbol->namespace;
2508 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\t%s\n",
2509 symbol->crc, symbol->name,
2510 symbol->module->name,
2511 export_str(symbol->export),
2512 namespace ? namespace : "");
2513 }
2514 symbol = symbol->next;
2515 }
2516 }
2517 write_if_changed(&buf, fname);
2518 free(buf.p);
2519 }
2520
2521 static void write_namespace_deps_files(const char *fname)
2522 {
2523 struct module *mod;
2524 struct namespace_list *ns;
2525 struct buffer ns_deps_buf = {};
2526
2527 for (mod = modules; mod; mod = mod->next) {
2528
2529 if (mod->skip || !mod->missing_namespaces)
2530 continue;
2531
2532 buf_printf(&ns_deps_buf, "%s.ko:", mod->name);
2533
2534 for (ns = mod->missing_namespaces; ns; ns = ns->next)
2535 buf_printf(&ns_deps_buf, " %s", ns->namespace);
2536
2537 buf_printf(&ns_deps_buf, "\n");
2538 }
2539
2540 write_if_changed(&ns_deps_buf, fname);
2541 free(ns_deps_buf.p);
2542 }
2543
2544 struct ext_sym_list {
2545 struct ext_sym_list *next;
2546 const char *file;
2547 };
2548
2549 int main(int argc, char **argv)
2550 {
2551 struct module *mod;
2552 struct buffer buf = { };
2553 char *kernel_read = NULL;
2554 char *missing_namespace_deps = NULL;
2555 char *dump_write = NULL, *files_source = NULL;
2556 int opt;
2557 int err;
2558 int n;
2559 struct ext_sym_list *extsym_iter;
2560 struct ext_sym_list *extsym_start = NULL;
2561
2562 while ((opt = getopt(argc, argv, "i:e:mnsT:o:awENd:")) != -1) {
2563 switch (opt) {
2564 case 'i':
2565 kernel_read = optarg;
2566 external_module = 1;
2567 break;
2568 case 'e':
2569 external_module = 1;
2570 extsym_iter =
2571 NOFAIL(malloc(sizeof(*extsym_iter)));
2572 extsym_iter->next = extsym_start;
2573 extsym_iter->file = optarg;
2574 extsym_start = extsym_iter;
2575 break;
2576 case 'm':
2577 modversions = 1;
2578 break;
2579 case 'n':
2580 ignore_missing_files = 1;
2581 break;
2582 case 'o':
2583 dump_write = optarg;
2584 break;
2585 case 'a':
2586 all_versions = 1;
2587 break;
2588 case 's':
2589 vmlinux_section_warnings = 0;
2590 break;
2591 case 'T':
2592 files_source = optarg;
2593 break;
2594 case 'w':
2595 warn_unresolved = 1;
2596 break;
2597 case 'E':
2598 sec_mismatch_fatal = 1;
2599 break;
2600 case 'N':
2601 allow_missing_ns_imports = 1;
2602 break;
2603 case 'd':
2604 missing_namespace_deps = optarg;
2605 break;
2606 default:
2607 exit(1);
2608 }
2609 }
2610
2611 if (kernel_read)
2612 read_dump(kernel_read, 1);
2613 while (extsym_start) {
2614 read_dump(extsym_start->file, 0);
2615 extsym_iter = extsym_start->next;
2616 free(extsym_start);
2617 extsym_start = extsym_iter;
2618 }
2619
2620 while (optind < argc)
2621 read_symbols(argv[optind++]);
2622
2623 if (files_source)
2624 read_symbols_from_files(files_source);
2625
2626 err = 0;
2627
2628 for (mod = modules; mod; mod = mod->next) {
2629 char fname[PATH_MAX];
2630
2631 if (mod->skip)
2632 continue;
2633
2634 buf.pos = 0;
2635
2636 err |= check_modname_len(mod);
2637 err |= check_exports(mod);
2638
2639 add_header(&buf, mod);
2640 add_intree_flag(&buf, !external_module);
2641 add_retpoline(&buf);
2642 add_staging_flag(&buf, mod->name);
2643 err |= add_versions(&buf, mod);
2644 add_depends(&buf, mod);
2645 add_moddevtable(&buf, mod);
2646 add_srcversion(&buf, mod);
2647
2648 sprintf(fname, "%s.mod.c", mod->name);
2649 write_if_changed(&buf, fname);
2650 }
2651
2652 if (missing_namespace_deps)
2653 write_namespace_deps_files(missing_namespace_deps);
2654
2655 if (dump_write)
2656 write_dump(dump_write);
2657 if (sec_mismatch_count && sec_mismatch_fatal)
2658 fatal("Section mismatches detected.\n"
2659 "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");
2660 for (n = 0; n < SYMBOL_HASH_SIZE; n++) {
2661 struct symbol *s;
2662
2663 for (s = symbolhash[n]; s; s = s->next) {
2664 /*
2665 * Do not check "vmlinux". This avoids the same warnings
2666 * shown twice, and false-positives for ARCH=um.
2667 */
2668 if (is_vmlinux(s->module->name) && !s->module->is_dot_o)
2669 continue;
2670
2671 if (s->is_static)
2672 warn("\"%s\" [%s] is a static %s\n",
2673 s->name, s->module->name,
2674 export_str(s->export));
2675 }
2676 }
2677
2678 free(buf.p);
2679
2680 return err;
2681 }
Linux with added FPC-III support