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Linux 4.16.11
[linux/fpc-iii.git] / scripts / mod / modpost.c
blob9917f928d0fdf0a0f82f2730c926fc6449e04121
1 /* Postprocess module symbol versions
2 *
3 * Copyright 2003 Kai Germaschewski
4 * Copyright 2002-2004 Rusty Russell, IBM Corporation
5 * Copyright 2006-2008 Sam Ravnborg
6 * Based in part on module-init-tools/depmod.c,file2alias
7 *
8 * This software may be used and distributed according to the terms
9 * of the GNU General Public License, incorporated herein by reference.
10 *
11 * Usage: modpost vmlinux module1.o module2.o ...
12 */
13
14 #define _GNU_SOURCE
15 #include <stdio.h>
16 #include <ctype.h>
17 #include <string.h>
18 #include <limits.h>
19 #include <stdbool.h>
20 #include <errno.h>
21 #include "modpost.h"
22 #include "../../include/generated/autoconf.h"
23 #include "../../include/linux/license.h"
24 #include "../../include/linux/export.h"
25
26 /* Are we using CONFIG_MODVERSIONS? */
27 static int modversions = 0;
28 /* Warn about undefined symbols? (do so if we have vmlinux) */
29 static int have_vmlinux = 0;
30 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */
31 static int all_versions = 0;
32 /* If we are modposting external module set to 1 */
33 static int external_module = 0;
34 /* Warn about section mismatch in vmlinux if set to 1 */
35 static int vmlinux_section_warnings = 1;
36 /* Only warn about unresolved symbols */
37 static int warn_unresolved = 0;
38 /* How a symbol is exported */
39 static int sec_mismatch_count = 0;
40 static int sec_mismatch_verbose = 1;
41 static int sec_mismatch_fatal = 0;
42 /* ignore missing files */
43 static int ignore_missing_files;
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 #define PRINTF __attribute__ ((format (printf, 1, 2)))
57
58 PRINTF void fatal(const char *fmt, ...)
59 {
60 va_list arglist;
61
62 fprintf(stderr, "FATAL: ");
63
64 va_start(arglist, fmt);
65 vfprintf(stderr, fmt, arglist);
66 va_end(arglist);
67
68 exit(1);
69 }
70
71 PRINTF void warn(const char *fmt, ...)
72 {
73 va_list arglist;
74
75 fprintf(stderr, "WARNING: ");
76
77 va_start(arglist, fmt);
78 vfprintf(stderr, fmt, arglist);
79 va_end(arglist);
80 }
81
82 PRINTF void merror(const char *fmt, ...)
83 {
84 va_list arglist;
85
86 fprintf(stderr, "ERROR: ");
87
88 va_start(arglist, fmt);
89 vfprintf(stderr, fmt, arglist);
90 va_end(arglist);
91 }
92
93 static inline bool strends(const char *str, const char *postfix)
94 {
95 if (strlen(str) < strlen(postfix))
96 return false;
97
98 return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0;
99 }
100
101 static int is_vmlinux(const char *modname)
102 {
103 const char *myname;
104
105 myname = strrchr(modname, '/');
106 if (myname)
107 myname++;
108 else
109 myname = modname;
110
111 return (strcmp(myname, "vmlinux") == 0) ||
112 (strcmp(myname, "vmlinux.o") == 0);
113 }
114
115 void *do_nofail(void *ptr, const char *expr)
116 {
117 if (!ptr)
118 fatal("modpost: Memory allocation failure: %s.\n", expr);
119
120 return ptr;
121 }
122
123 /* A list of all modules we processed */
124 static struct module *modules;
125
126 static struct module *find_module(char *modname)
127 {
128 struct module *mod;
129
130 for (mod = modules; mod; mod = mod->next)
131 if (strcmp(mod->name, modname) == 0)
132 break;
133 return mod;
134 }
135
136 static struct module *new_module(const char *modname)
137 {
138 struct module *mod;
139 char *p;
140
141 mod = NOFAIL(malloc(sizeof(*mod)));
142 memset(mod, 0, sizeof(*mod));
143 p = NOFAIL(strdup(modname));
144
145 /* strip trailing .o */
146 if (strends(p, ".o")) {
147 p[strlen(p) - 2] = '\0';
148 mod->is_dot_o = 1;
149 }
150
151 /* add to list */
152 mod->name = p;
153 mod->gpl_compatible = -1;
154 mod->next = modules;
155 modules = mod;
156
157 return mod;
158 }
159
160 /* A hash of all exported symbols,
161 * struct symbol is also used for lists of unresolved symbols */
162
163 #define SYMBOL_HASH_SIZE 1024
164
165 struct symbol {
166 struct symbol *next;
167 struct module *module;
168 unsigned int crc;
169 int crc_valid;
170 unsigned int weak:1;
171 unsigned int vmlinux:1; /* 1 if symbol is defined in vmlinux */
172 unsigned int kernel:1; /* 1 if symbol is from kernel
173 * (only for external modules) **/
174 unsigned int preloaded:1; /* 1 if symbol from Module.symvers, or crc */
175 enum export export; /* Type of export */
176 char name[0];
177 };
178
179 static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
180
181 /* This is based on the hash agorithm from gdbm, via tdb */
182 static inline unsigned int tdb_hash(const char *name)
183 {
184 unsigned value; /* Used to compute the hash value. */
185 unsigned i; /* Used to cycle through random values. */
186
187 /* Set the initial value from the key size. */
188 for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
189 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
190
191 return (1103515243 * value + 12345);
192 }
193
194 /**
195 * Allocate a new symbols for use in the hash of exported symbols or
196 * the list of unresolved symbols per module
197 **/
198 static struct symbol *alloc_symbol(const char *name, unsigned int weak,
199 struct symbol *next)
200 {
201 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
202
203 memset(s, 0, sizeof(*s));
204 strcpy(s->name, name);
205 s->weak = weak;
206 s->next = next;
207 return s;
208 }
209
210 /* For the hash of exported symbols */
211 static struct symbol *new_symbol(const char *name, struct module *module,
212 enum export export)
213 {
214 unsigned int hash;
215 struct symbol *new;
216
217 hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
218 new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
219 new->module = module;
220 new->export = export;
221 return new;
222 }
223
224 static struct symbol *find_symbol(const char *name)
225 {
226 struct symbol *s;
227
228 /* For our purposes, .foo matches foo. PPC64 needs this. */
229 if (name[0] == '.')
230 name++;
231
232 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
233 if (strcmp(s->name, name) == 0)
234 return s;
235 }
236 return NULL;
237 }
238
239 static const struct {
240 const char *str;
241 enum export export;
242 } export_list[] = {
243 { .str = "EXPORT_SYMBOL", .export = export_plain },
244 { .str = "EXPORT_UNUSED_SYMBOL", .export = export_unused },
245 { .str = "EXPORT_SYMBOL_GPL", .export = export_gpl },
246 { .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
247 { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
248 { .str = "(unknown)", .export = export_unknown },
249 };
250
251
252 static const char *export_str(enum export ex)
253 {
254 return export_list[ex].str;
255 }
256
257 static enum export export_no(const char *s)
258 {
259 int i;
260
261 if (!s)
262 return export_unknown;
263 for (i = 0; export_list[i].export != export_unknown; i++) {
264 if (strcmp(export_list[i].str, s) == 0)
265 return export_list[i].export;
266 }
267 return export_unknown;
268 }
269
270 static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr)
271 {
272 return (void *)elf->hdr +
273 elf->sechdrs[elf->secindex_strings].sh_offset +
274 sechdr->sh_name;
275 }
276
277 static const char *sec_name(struct elf_info *elf, int secindex)
278 {
279 return sech_name(elf, &elf->sechdrs[secindex]);
280 }
281
282 #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)
283
284 static enum export export_from_secname(struct elf_info *elf, unsigned int sec)
285 {
286 const char *secname = sec_name(elf, sec);
287
288 if (strstarts(secname, "___ksymtab+"))
289 return export_plain;
290 else if (strstarts(secname, "___ksymtab_unused+"))
291 return export_unused;
292 else if (strstarts(secname, "___ksymtab_gpl+"))
293 return export_gpl;
294 else if (strstarts(secname, "___ksymtab_unused_gpl+"))
295 return export_unused_gpl;
296 else if (strstarts(secname, "___ksymtab_gpl_future+"))
297 return export_gpl_future;
298 else
299 return export_unknown;
300 }
301
302 static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
303 {
304 if (sec == elf->export_sec)
305 return export_plain;
306 else if (sec == elf->export_unused_sec)
307 return export_unused;
308 else if (sec == elf->export_gpl_sec)
309 return export_gpl;
310 else if (sec == elf->export_unused_gpl_sec)
311 return export_unused_gpl;
312 else if (sec == elf->export_gpl_future_sec)
313 return export_gpl_future;
314 else
315 return export_unknown;
316 }
317
318 /**
319 * Add an exported symbol - it may have already been added without a
320 * CRC, in this case just update the CRC
321 **/
322 static struct symbol *sym_add_exported(const char *name, struct module *mod,
323 enum export export)
324 {
325 struct symbol *s = find_symbol(name);
326
327 if (!s) {
328 s = new_symbol(name, mod, export);
329 } else {
330 if (!s->preloaded) {
331 warn("%s: '%s' exported twice. Previous export "
332 "was in %s%s\n", mod->name, name,
333 s->module->name,
334 is_vmlinux(s->module->name) ?"":".ko");
335 } else {
336 /* In case Module.symvers was out of date */
337 s->module = mod;
338 }
339 }
340 s->preloaded = 0;
341 s->vmlinux = is_vmlinux(mod->name);
342 s->kernel = 0;
343 s->export = export;
344 return s;
345 }
346
347 static void sym_update_crc(const char *name, struct module *mod,
348 unsigned int crc, enum export export)
349 {
350 struct symbol *s = find_symbol(name);
351
352 if (!s) {
353 s = new_symbol(name, mod, export);
354 /* Don't complain when we find it later. */
355 s->preloaded = 1;
356 }
357 s->crc = crc;
358 s->crc_valid = 1;
359 }
360
361 void *grab_file(const char *filename, unsigned long *size)
362 {
363 struct stat st;
364 void *map = MAP_FAILED;
365 int fd;
366
367 fd = open(filename, O_RDONLY);
368 if (fd < 0)
369 return NULL;
370 if (fstat(fd, &st))
371 goto failed;
372
373 *size = st.st_size;
374 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
375
376 failed:
377 close(fd);
378 if (map == MAP_FAILED)
379 return NULL;
380 return map;
381 }
382
383 /**
384 * Return a copy of the next line in a mmap'ed file.
385 * spaces in the beginning of the line is trimmed away.
386 * Return a pointer to a static buffer.
387 **/
388 char *get_next_line(unsigned long *pos, void *file, unsigned long size)
389 {
390 static char line[4096];
391 int skip = 1;
392 size_t len = 0;
393 signed char *p = (signed char *)file + *pos;
394 char *s = line;
395
396 for (; *pos < size ; (*pos)++) {
397 if (skip && isspace(*p)) {
398 p++;
399 continue;
400 }
401 skip = 0;
402 if (*p != '\n' && (*pos < size)) {
403 len++;
404 *s++ = *p++;
405 if (len > 4095)
406 break; /* Too long, stop */
407 } else {
408 /* End of string */
409 *s = '\0';
410 return line;
411 }
412 }
413 /* End of buffer */
414 return NULL;
415 }
416
417 void release_file(void *file, unsigned long size)
418 {
419 munmap(file, size);
420 }
421
422 static int parse_elf(struct elf_info *info, const char *filename)
423 {
424 unsigned int i;
425 Elf_Ehdr *hdr;
426 Elf_Shdr *sechdrs;
427 Elf_Sym *sym;
428 const char *secstrings;
429 unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
430
431 hdr = grab_file(filename, &info->size);
432 if (!hdr) {
433 if (ignore_missing_files) {
434 fprintf(stderr, "%s: %s (ignored)\n", filename,
435 strerror(errno));
436 return 0;
437 }
438 perror(filename);
439 exit(1);
440 }
441 info->hdr = hdr;
442 if (info->size < sizeof(*hdr)) {
443 /* file too small, assume this is an empty .o file */
444 return 0;
445 }
446 /* Is this a valid ELF file? */
447 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
448 (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
449 (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
450 (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
451 /* Not an ELF file - silently ignore it */
452 return 0;
453 }
454 /* Fix endianness in ELF header */
455 hdr->e_type = TO_NATIVE(hdr->e_type);
456 hdr->e_machine = TO_NATIVE(hdr->e_machine);
457 hdr->e_version = TO_NATIVE(hdr->e_version);
458 hdr->e_entry = TO_NATIVE(hdr->e_entry);
459 hdr->e_phoff = TO_NATIVE(hdr->e_phoff);
460 hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
461 hdr->e_flags = TO_NATIVE(hdr->e_flags);
462 hdr->e_ehsize = TO_NATIVE(hdr->e_ehsize);
463 hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
464 hdr->e_phnum = TO_NATIVE(hdr->e_phnum);
465 hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
466 hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
467 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
468 sechdrs = (void *)hdr + hdr->e_shoff;
469 info->sechdrs = sechdrs;
470
471 /* Check if file offset is correct */
472 if (hdr->e_shoff > info->size) {
473 fatal("section header offset=%lu in file '%s' is bigger than "
474 "filesize=%lu\n", (unsigned long)hdr->e_shoff,
475 filename, info->size);
476 return 0;
477 }
478
479 if (hdr->e_shnum == SHN_UNDEF) {
480 /*
481 * There are more than 64k sections,
482 * read count from .sh_size.
483 */
484 info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
485 }
486 else {
487 info->num_sections = hdr->e_shnum;
488 }
489 if (hdr->e_shstrndx == SHN_XINDEX) {
490 info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
491 }
492 else {
493 info->secindex_strings = hdr->e_shstrndx;
494 }
495
496 /* Fix endianness in section headers */
497 for (i = 0; i < info->num_sections; i++) {
498 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
499 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
500 sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags);
501 sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr);
502 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
503 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
504 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
505 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info);
506 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
507 sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize);
508 }
509 /* Find symbol table. */
510 secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
511 for (i = 1; i < info->num_sections; i++) {
512 const char *secname;
513 int nobits = sechdrs[i].sh_type == SHT_NOBITS;
514
515 if (!nobits && sechdrs[i].sh_offset > info->size) {
516 fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
517 "sizeof(*hrd)=%zu\n", filename,
518 (unsigned long)sechdrs[i].sh_offset,
519 sizeof(*hdr));
520 return 0;
521 }
522 secname = secstrings + sechdrs[i].sh_name;
523 if (strcmp(secname, ".modinfo") == 0) {
524 if (nobits)
525 fatal("%s has NOBITS .modinfo\n", filename);
526 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
527 info->modinfo_len = sechdrs[i].sh_size;
528 } else if (strcmp(secname, "__ksymtab") == 0)
529 info->export_sec = i;
530 else if (strcmp(secname, "__ksymtab_unused") == 0)
531 info->export_unused_sec = i;
532 else if (strcmp(secname, "__ksymtab_gpl") == 0)
533 info->export_gpl_sec = i;
534 else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
535 info->export_unused_gpl_sec = i;
536 else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
537 info->export_gpl_future_sec = i;
538
539 if (sechdrs[i].sh_type == SHT_SYMTAB) {
540 unsigned int sh_link_idx;
541 symtab_idx = i;
542 info->symtab_start = (void *)hdr +
543 sechdrs[i].sh_offset;
544 info->symtab_stop = (void *)hdr +
545 sechdrs[i].sh_offset + sechdrs[i].sh_size;
546 sh_link_idx = sechdrs[i].sh_link;
547 info->strtab = (void *)hdr +
548 sechdrs[sh_link_idx].sh_offset;
549 }
550
551 /* 32bit section no. table? ("more than 64k sections") */
552 if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
553 symtab_shndx_idx = i;
554 info->symtab_shndx_start = (void *)hdr +
555 sechdrs[i].sh_offset;
556 info->symtab_shndx_stop = (void *)hdr +
557 sechdrs[i].sh_offset + sechdrs[i].sh_size;
558 }
559 }
560 if (!info->symtab_start)
561 fatal("%s has no symtab?\n", filename);
562
563 /* Fix endianness in symbols */
564 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
565 sym->st_shndx = TO_NATIVE(sym->st_shndx);
566 sym->st_name = TO_NATIVE(sym->st_name);
567 sym->st_value = TO_NATIVE(sym->st_value);
568 sym->st_size = TO_NATIVE(sym->st_size);
569 }
570
571 if (symtab_shndx_idx != ~0U) {
572 Elf32_Word *p;
573 if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
574 fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
575 filename, sechdrs[symtab_shndx_idx].sh_link,
576 symtab_idx);
577 /* Fix endianness */
578 for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
579 p++)
580 *p = TO_NATIVE(*p);
581 }
582
583 return 1;
584 }
585
586 static void parse_elf_finish(struct elf_info *info)
587 {
588 release_file(info->hdr, info->size);
589 }
590
591 static int ignore_undef_symbol(struct elf_info *info, const char *symname)
592 {
593 /* ignore __this_module, it will be resolved shortly */
594 if (strcmp(symname, VMLINUX_SYMBOL_STR(__this_module)) == 0)
595 return 1;
596 /* ignore global offset table */
597 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
598 return 1;
599 if (info->hdr->e_machine == EM_PPC)
600 /* Special register function linked on all modules during final link of .ko */
601 if (strncmp(symname, "_restgpr_", sizeof("_restgpr_") - 1) == 0 ||
602 strncmp(symname, "_savegpr_", sizeof("_savegpr_") - 1) == 0 ||
603 strncmp(symname, "_rest32gpr_", sizeof("_rest32gpr_") - 1) == 0 ||
604 strncmp(symname, "_save32gpr_", sizeof("_save32gpr_") - 1) == 0 ||
605 strncmp(symname, "_restvr_", sizeof("_restvr_") - 1) == 0 ||
606 strncmp(symname, "_savevr_", sizeof("_savevr_") - 1) == 0)
607 return 1;
608 if (info->hdr->e_machine == EM_PPC64)
609 /* Special register function linked on all modules during final link of .ko */
610 if (strncmp(symname, "_restgpr0_", sizeof("_restgpr0_") - 1) == 0 ||
611 strncmp(symname, "_savegpr0_", sizeof("_savegpr0_") - 1) == 0 ||
612 strncmp(symname, "_restvr_", sizeof("_restvr_") - 1) == 0 ||
613 strncmp(symname, "_savevr_", sizeof("_savevr_") - 1) == 0 ||
614 strcmp(symname, ".TOC.") == 0)
615 return 1;
616 /* Do not ignore this symbol */
617 return 0;
618 }
619
620 #define CRC_PFX VMLINUX_SYMBOL_STR(__crc_)
621 #define KSYMTAB_PFX VMLINUX_SYMBOL_STR(__ksymtab_)
622
623 static void handle_modversions(struct module *mod, struct elf_info *info,
624 Elf_Sym *sym, const char *symname)
625 {
626 unsigned int crc;
627 enum export export;
628 bool is_crc = false;
629
630 if ((!is_vmlinux(mod->name) || mod->is_dot_o) &&
631 strncmp(symname, "__ksymtab", 9) == 0)
632 export = export_from_secname(info, get_secindex(info, sym));
633 else
634 export = export_from_sec(info, get_secindex(info, sym));
635
636 /* CRC'd symbol */
637 if (strncmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
638 is_crc = true;
639 crc = (unsigned int) sym->st_value;
640 if (sym->st_shndx != SHN_UNDEF && sym->st_shndx != SHN_ABS) {
641 unsigned int *crcp;
642
643 /* symbol points to the CRC in the ELF object */
644 crcp = (void *)info->hdr + sym->st_value +
645 info->sechdrs[sym->st_shndx].sh_offset -
646 (info->hdr->e_type != ET_REL ?
647 info->sechdrs[sym->st_shndx].sh_addr : 0);
648 crc = *crcp;
649 }
650 sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
651 export);
652 }
653
654 switch (sym->st_shndx) {
655 case SHN_COMMON:
656 if (!strncmp(symname, "__gnu_lto_", sizeof("__gnu_lto_")-1)) {
657 /* Should warn here, but modpost runs before the linker */
658 } else
659 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
660 break;
661 case SHN_UNDEF:
662 /* undefined symbol */
663 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
664 ELF_ST_BIND(sym->st_info) != STB_WEAK)
665 break;
666 if (ignore_undef_symbol(info, symname))
667 break;
668 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
669 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
670 /* add compatibility with older glibc */
671 #ifndef STT_SPARC_REGISTER
672 #define STT_SPARC_REGISTER STT_REGISTER
673 #endif
674 if (info->hdr->e_machine == EM_SPARC ||
675 info->hdr->e_machine == EM_SPARCV9) {
676 /* Ignore register directives. */
677 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
678 break;
679 if (symname[0] == '.') {
680 char *munged = strdup(symname);
681 munged[0] = '_';
682 munged[1] = toupper(munged[1]);
683 symname = munged;
684 }
685 }
686 #endif
687
688 #ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX
689 if (symname[0] != '_')
690 break;
691 else
692 symname++;
693 #endif
694 if (is_crc) {
695 const char *e = is_vmlinux(mod->name) ?"":".ko";
696 warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n", symname + strlen(CRC_PFX), mod->name, e);
697 }
698 mod->unres = alloc_symbol(symname,
699 ELF_ST_BIND(sym->st_info) == STB_WEAK,
700 mod->unres);
701 break;
702 default:
703 /* All exported symbols */
704 if (strncmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
705 sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
706 export);
707 }
708 if (strcmp(symname, VMLINUX_SYMBOL_STR(init_module)) == 0)
709 mod->has_init = 1;
710 if (strcmp(symname, VMLINUX_SYMBOL_STR(cleanup_module)) == 0)
711 mod->has_cleanup = 1;
712 break;
713 }
714 }
715
716 /**
717 * Parse tag=value strings from .modinfo section
718 **/
719 static char *next_string(char *string, unsigned long *secsize)
720 {
721 /* Skip non-zero chars */
722 while (string[0]) {
723 string++;
724 if ((*secsize)-- <= 1)
725 return NULL;
726 }
727
728 /* Skip any zero padding. */
729 while (!string[0]) {
730 string++;
731 if ((*secsize)-- <= 1)
732 return NULL;
733 }
734 return string;
735 }
736
737 static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
738 const char *tag, char *info)
739 {
740 char *p;
741 unsigned int taglen = strlen(tag);
742 unsigned long size = modinfo_len;
743
744 if (info) {
745 size -= info - (char *)modinfo;
746 modinfo = next_string(info, &size);
747 }
748
749 for (p = modinfo; p; p = next_string(p, &size)) {
750 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
751 return p + taglen + 1;
752 }
753 return NULL;
754 }
755
756 static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
757 const char *tag)
758
759 {
760 return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
761 }
762
763 /**
764 * Test if string s ends in string sub
765 * return 0 if match
766 **/
767 static int strrcmp(const char *s, const char *sub)
768 {
769 int slen, sublen;
770
771 if (!s || !sub)
772 return 1;
773
774 slen = strlen(s);
775 sublen = strlen(sub);
776
777 if ((slen == 0) || (sublen == 0))
778 return 1;
779
780 if (sublen > slen)
781 return 1;
782
783 return memcmp(s + slen - sublen, sub, sublen);
784 }
785
786 static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
787 {
788 if (sym)
789 return elf->strtab + sym->st_name;
790 else
791 return "(unknown)";
792 }
793
794 /* The pattern is an array of simple patterns.
795 * "foo" will match an exact string equal to "foo"
796 * "*foo" will match a string that ends with "foo"
797 * "foo*" will match a string that begins with "foo"
798 * "*foo*" will match a string that contains "foo"
799 */
800 static int match(const char *sym, const char * const pat[])
801 {
802 const char *p;
803 while (*pat) {
804 p = *pat++;
805 const char *endp = p + strlen(p) - 1;
806
807 /* "*foo*" */
808 if (*p == '*' && *endp == '*') {
809 char *here, *bare = strndup(p + 1, strlen(p) - 2);
810
811 here = strstr(sym, bare);
812 free(bare);
813 if (here != NULL)
814 return 1;
815 }
816 /* "*foo" */
817 else if (*p == '*') {
818 if (strrcmp(sym, p + 1) == 0)
819 return 1;
820 }
821 /* "foo*" */
822 else if (*endp == '*') {
823 if (strncmp(sym, p, strlen(p) - 1) == 0)
824 return 1;
825 }
826 /* no wildcards */
827 else {
828 if (strcmp(p, sym) == 0)
829 return 1;
830 }
831 }
832 /* no match */
833 return 0;
834 }
835
836 /* sections that we do not want to do full section mismatch check on */
837 static const char *const section_white_list[] =
838 {
839 ".comment*",
840 ".debug*",
841 ".cranges", /* sh64 */
842 ".zdebug*", /* Compressed debug sections. */
843 ".GCC-command-line", /* mn10300 */
844 ".GCC.command.line", /* record-gcc-switches, non mn10300 */
845 ".mdebug*", /* alpha, score, mips etc. */
846 ".pdr", /* alpha, score, mips etc. */
847 ".stab*",
848 ".note*",
849 ".got*",
850 ".toc*",
851 ".xt.prop", /* xtensa */
852 ".xt.lit", /* xtensa */
853 ".arcextmap*", /* arc */
854 ".gnu.linkonce.arcext*", /* arc : modules */
855 ".cmem*", /* EZchip */
856 ".fmt_slot*", /* EZchip */
857 ".gnu.lto*",
858 ".discard.*",
859 NULL
860 };
861
862 /*
863 * This is used to find sections missing the SHF_ALLOC flag.
864 * The cause of this is often a section specified in assembler
865 * without "ax" / "aw".
866 */
867 static void check_section(const char *modname, struct elf_info *elf,
868 Elf_Shdr *sechdr)
869 {
870 const char *sec = sech_name(elf, sechdr);
871
872 if (sechdr->sh_type == SHT_PROGBITS &&
873 !(sechdr->sh_flags & SHF_ALLOC) &&
874 !match(sec, section_white_list)) {
875 warn("%s (%s): unexpected non-allocatable section.\n"
876 "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
877 "Note that for example <linux/init.h> contains\n"
878 "section definitions for use in .S files.\n\n",
879 modname, sec);
880 }
881 }
882
883
884
885 #define ALL_INIT_DATA_SECTIONS \
886 ".init.setup", ".init.rodata", ".meminit.rodata", \
887 ".init.data", ".meminit.data"
888 #define ALL_EXIT_DATA_SECTIONS \
889 ".exit.data", ".memexit.data"
890
891 #define ALL_INIT_TEXT_SECTIONS \
892 ".init.text", ".meminit.text"
893 #define ALL_EXIT_TEXT_SECTIONS \
894 ".exit.text", ".memexit.text"
895
896 #define ALL_PCI_INIT_SECTIONS \
897 ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
898 ".pci_fixup_enable", ".pci_fixup_resume", \
899 ".pci_fixup_resume_early", ".pci_fixup_suspend"
900
901 #define ALL_XXXINIT_SECTIONS MEM_INIT_SECTIONS
902 #define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS
903
904 #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
905 #define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
906
907 #define DATA_SECTIONS ".data", ".data.rel"
908 #define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \
909 ".kprobes.text", ".cpuidle.text"
910 #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
911 ".fixup", ".entry.text", ".exception.text", ".text.*", \
912 ".coldtext"
913
914 #define INIT_SECTIONS ".init.*"
915 #define MEM_INIT_SECTIONS ".meminit.*"
916
917 #define EXIT_SECTIONS ".exit.*"
918 #define MEM_EXIT_SECTIONS ".memexit.*"
919
920 #define ALL_TEXT_SECTIONS ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \
921 TEXT_SECTIONS, OTHER_TEXT_SECTIONS
922
923 /* init data sections */
924 static const char *const init_data_sections[] =
925 { ALL_INIT_DATA_SECTIONS, NULL };
926
927 /* all init sections */
928 static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL };
929
930 /* All init and exit sections (code + data) */
931 static const char *const init_exit_sections[] =
932 {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
933
934 /* all text sections */
935 static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL };
936
937 /* data section */
938 static const char *const data_sections[] = { DATA_SECTIONS, NULL };
939
940
941 /* symbols in .data that may refer to init/exit sections */
942 #define DEFAULT_SYMBOL_WHITE_LIST \
943 "*driver", \
944 "*_template", /* scsi uses *_template a lot */ \
945 "*_timer", /* arm uses ops structures named _timer a lot */ \
946 "*_sht", /* scsi also used *_sht to some extent */ \
947 "*_ops", \
948 "*_probe", \
949 "*_probe_one", \
950 "*_console"
951
952 static const char *const head_sections[] = { ".head.text*", NULL };
953 static const char *const linker_symbols[] =
954 { "__init_begin", "_sinittext", "_einittext", NULL };
955 static const char *const optim_symbols[] = { "*.constprop.*", NULL };
956
957 enum mismatch {
958 TEXT_TO_ANY_INIT,
959 DATA_TO_ANY_INIT,
960 TEXT_TO_ANY_EXIT,
961 DATA_TO_ANY_EXIT,
962 XXXINIT_TO_SOME_INIT,
963 XXXEXIT_TO_SOME_EXIT,
964 ANY_INIT_TO_ANY_EXIT,
965 ANY_EXIT_TO_ANY_INIT,
966 EXPORT_TO_INIT_EXIT,
967 EXTABLE_TO_NON_TEXT,
968 };
969
970 /**
971 * Describe how to match sections on different criterias:
972 *
973 * @fromsec: Array of sections to be matched.
974 *
975 * @bad_tosec: Relocations applied to a section in @fromsec to a section in
976 * this array is forbidden (black-list). Can be empty.
977 *
978 * @good_tosec: Relocations applied to a section in @fromsec must be
979 * targetting sections in this array (white-list). Can be empty.
980 *
981 * @mismatch: Type of mismatch.
982 *
983 * @symbol_white_list: Do not match a relocation to a symbol in this list
984 * even if it is targetting a section in @bad_to_sec.
985 *
986 * @handler: Specific handler to call when a match is found. If NULL,
987 * default_mismatch_handler() will be called.
988 *
989 */
990 struct sectioncheck {
991 const char *fromsec[20];
992 const char *bad_tosec[20];
993 const char *good_tosec[20];
994 enum mismatch mismatch;
995 const char *symbol_white_list[20];
996 void (*handler)(const char *modname, struct elf_info *elf,
997 const struct sectioncheck* const mismatch,
998 Elf_Rela *r, Elf_Sym *sym, const char *fromsec);
999
1000 };
1001
1002 static void extable_mismatch_handler(const char *modname, struct elf_info *elf,
1003 const struct sectioncheck* const mismatch,
1004 Elf_Rela *r, Elf_Sym *sym,
1005 const char *fromsec);
1006
1007 static const struct sectioncheck sectioncheck[] = {
1008 /* Do not reference init/exit code/data from
1009 * normal code and data
1010 */
1011 {
1012 .fromsec = { TEXT_SECTIONS, NULL },
1013 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1014 .mismatch = TEXT_TO_ANY_INIT,
1015 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1016 },
1017 {
1018 .fromsec = { DATA_SECTIONS, NULL },
1019 .bad_tosec = { ALL_XXXINIT_SECTIONS, NULL },
1020 .mismatch = DATA_TO_ANY_INIT,
1021 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1022 },
1023 {
1024 .fromsec = { DATA_SECTIONS, NULL },
1025 .bad_tosec = { INIT_SECTIONS, NULL },
1026 .mismatch = DATA_TO_ANY_INIT,
1027 .symbol_white_list = {
1028 "*_template", "*_timer", "*_sht", "*_ops",
1029 "*_probe", "*_probe_one", "*_console", NULL
1030 },
1031 },
1032 {
1033 .fromsec = { TEXT_SECTIONS, NULL },
1034 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1035 .mismatch = TEXT_TO_ANY_EXIT,
1036 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1037 },
1038 {
1039 .fromsec = { DATA_SECTIONS, NULL },
1040 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1041 .mismatch = DATA_TO_ANY_EXIT,
1042 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1043 },
1044 /* Do not reference init code/data from meminit code/data */
1045 {
1046 .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
1047 .bad_tosec = { INIT_SECTIONS, NULL },
1048 .mismatch = XXXINIT_TO_SOME_INIT,
1049 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1050 },
1051 /* Do not reference exit code/data from memexit code/data */
1052 {
1053 .fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
1054 .bad_tosec = { EXIT_SECTIONS, NULL },
1055 .mismatch = XXXEXIT_TO_SOME_EXIT,
1056 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1057 },
1058 /* Do not use exit code/data from init code */
1059 {
1060 .fromsec = { ALL_INIT_SECTIONS, NULL },
1061 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1062 .mismatch = ANY_INIT_TO_ANY_EXIT,
1063 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1064 },
1065 /* Do not use init code/data from exit code */
1066 {
1067 .fromsec = { ALL_EXIT_SECTIONS, NULL },
1068 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1069 .mismatch = ANY_EXIT_TO_ANY_INIT,
1070 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1071 },
1072 {
1073 .fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
1074 .bad_tosec = { INIT_SECTIONS, NULL },
1075 .mismatch = ANY_INIT_TO_ANY_EXIT,
1076 .symbol_white_list = { NULL },
1077 },
1078 /* Do not export init/exit functions or data */
1079 {
1080 .fromsec = { "__ksymtab*", NULL },
1081 .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
1082 .mismatch = EXPORT_TO_INIT_EXIT,
1083 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1084 },
1085 {
1086 .fromsec = { "__ex_table", NULL },
1087 /* If you're adding any new black-listed sections in here, consider
1088 * adding a special 'printer' for them in scripts/check_extable.
1089 */
1090 .bad_tosec = { ".altinstr_replacement", NULL },
1091 .good_tosec = {ALL_TEXT_SECTIONS , NULL},
1092 .mismatch = EXTABLE_TO_NON_TEXT,
1093 .handler = extable_mismatch_handler,
1094 }
1095 };
1096
1097 static const struct sectioncheck *section_mismatch(
1098 const char *fromsec, const char *tosec)
1099 {
1100 int i;
1101 int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
1102 const struct sectioncheck *check = &sectioncheck[0];
1103
1104 /*
1105 * The target section could be the SHT_NUL section when we're
1106 * handling relocations to un-resolved symbols, trying to match it
1107 * doesn't make much sense and causes build failures on parisc and
1108 * mn10300 architectures.
1109 */
1110 if (*tosec == '\0')
1111 return NULL;
1112
1113 for (i = 0; i < elems; i++) {
1114 if (match(fromsec, check->fromsec)) {
1115 if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
1116 return check;
1117 if (check->good_tosec[0] && !match(tosec, check->good_tosec))
1118 return check;
1119 }
1120 check++;
1121 }
1122 return NULL;
1123 }
1124
1125 /**
1126 * Whitelist to allow certain references to pass with no warning.
1127 *
1128 * Pattern 1:
1129 * If a module parameter is declared __initdata and permissions=0
1130 * then this is legal despite the warning generated.
1131 * We cannot see value of permissions here, so just ignore
1132 * this pattern.
1133 * The pattern is identified by:
1134 * tosec = .init.data
1135 * fromsec = .data*
1136 * atsym =__param*
1137 *
1138 * Pattern 1a:
1139 * module_param_call() ops can refer to __init set function if permissions=0
1140 * The pattern is identified by:
1141 * tosec = .init.text
1142 * fromsec = .data*
1143 * atsym = __param_ops_*
1144 *
1145 * Pattern 2:
1146 * Many drivers utilise a *driver container with references to
1147 * add, remove, probe functions etc.
1148 * the pattern is identified by:
1149 * tosec = init or exit section
1150 * fromsec = data section
1151 * atsym = *driver, *_template, *_sht, *_ops, *_probe,
1152 * *probe_one, *_console, *_timer
1153 *
1154 * Pattern 3:
1155 * Whitelist all references from .head.text to any init section
1156 *
1157 * Pattern 4:
1158 * Some symbols belong to init section but still it is ok to reference
1159 * these from non-init sections as these symbols don't have any memory
1160 * allocated for them and symbol address and value are same. So even
1161 * if init section is freed, its ok to reference those symbols.
1162 * For ex. symbols marking the init section boundaries.
1163 * This pattern is identified by
1164 * refsymname = __init_begin, _sinittext, _einittext
1165 *
1166 * Pattern 5:
1167 * GCC may optimize static inlines when fed constant arg(s) resulting
1168 * in functions like cpumask_empty() -- generating an associated symbol
1169 * cpumask_empty.constprop.3 that appears in the audit. If the const that
1170 * is passed in comes from __init, like say nmi_ipi_mask, we get a
1171 * meaningless section warning. May need to add isra symbols too...
1172 * This pattern is identified by
1173 * tosec = init section
1174 * fromsec = text section
1175 * refsymname = *.constprop.*
1176 *
1177 **/
1178 static int secref_whitelist(const struct sectioncheck *mismatch,
1179 const char *fromsec, const char *fromsym,
1180 const char *tosec, const char *tosym)
1181 {
1182 /* Check for pattern 1 */
1183 if (match(tosec, init_data_sections) &&
1184 match(fromsec, data_sections) &&
1185 (strncmp(fromsym, "__param", strlen("__param")) == 0))
1186 return 0;
1187
1188 /* Check for pattern 1a */
1189 if (strcmp(tosec, ".init.text") == 0 &&
1190 match(fromsec, data_sections) &&
1191 (strncmp(fromsym, "__param_ops_", strlen("__param_ops_")) == 0))
1192 return 0;
1193
1194 /* Check for pattern 2 */
1195 if (match(tosec, init_exit_sections) &&
1196 match(fromsec, data_sections) &&
1197 match(fromsym, mismatch->symbol_white_list))
1198 return 0;
1199
1200 /* Check for pattern 3 */
1201 if (match(fromsec, head_sections) &&
1202 match(tosec, init_sections))
1203 return 0;
1204
1205 /* Check for pattern 4 */
1206 if (match(tosym, linker_symbols))
1207 return 0;
1208
1209 /* Check for pattern 5 */
1210 if (match(fromsec, text_sections) &&
1211 match(tosec, init_sections) &&
1212 match(fromsym, optim_symbols))
1213 return 0;
1214
1215 return 1;
1216 }
1217
1218 /**
1219 * Find symbol based on relocation record info.
1220 * In some cases the symbol supplied is a valid symbol so
1221 * return refsym. If st_name != 0 we assume this is a valid symbol.
1222 * In other cases the symbol needs to be looked up in the symbol table
1223 * based on section and address.
1224 * **/
1225 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
1226 Elf_Sym *relsym)
1227 {
1228 Elf_Sym *sym;
1229 Elf_Sym *near = NULL;
1230 Elf64_Sword distance = 20;
1231 Elf64_Sword d;
1232 unsigned int relsym_secindex;
1233
1234 if (relsym->st_name != 0)
1235 return relsym;
1236
1237 relsym_secindex = get_secindex(elf, relsym);
1238 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1239 if (get_secindex(elf, sym) != relsym_secindex)
1240 continue;
1241 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
1242 continue;
1243 if (sym->st_value == addr)
1244 return sym;
1245 /* Find a symbol nearby - addr are maybe negative */
1246 d = sym->st_value - addr;
1247 if (d < 0)
1248 d = addr - sym->st_value;
1249 if (d < distance) {
1250 distance = d;
1251 near = sym;
1252 }
1253 }
1254 /* We need a close match */
1255 if (distance < 20)
1256 return near;
1257 else
1258 return NULL;
1259 }
1260
1261 static inline int is_arm_mapping_symbol(const char *str)
1262 {
1263 return str[0] == '$' && strchr("axtd", str[1])
1264 && (str[2] == '\0' || str[2] == '.');
1265 }
1266
1267 /*
1268 * If there's no name there, ignore it; likewise, ignore it if it's
1269 * one of the magic symbols emitted used by current ARM tools.
1270 *
1271 * Otherwise if find_symbols_between() returns those symbols, they'll
1272 * fail the whitelist tests and cause lots of false alarms ... fixable
1273 * only by merging __exit and __init sections into __text, bloating
1274 * the kernel (which is especially evil on embedded platforms).
1275 */
1276 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1277 {
1278 const char *name = elf->strtab + sym->st_name;
1279
1280 if (!name || !strlen(name))
1281 return 0;
1282 return !is_arm_mapping_symbol(name);
1283 }
1284
1285 /*
1286 * Find symbols before or equal addr and after addr - in the section sec.
1287 * If we find two symbols with equal offset prefer one with a valid name.
1288 * The ELF format may have a better way to detect what type of symbol
1289 * it is, but this works for now.
1290 **/
1291 static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1292 const char *sec)
1293 {
1294 Elf_Sym *sym;
1295 Elf_Sym *near = NULL;
1296 Elf_Addr distance = ~0;
1297
1298 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1299 const char *symsec;
1300
1301 if (is_shndx_special(sym->st_shndx))
1302 continue;
1303 symsec = sec_name(elf, get_secindex(elf, sym));
1304 if (strcmp(symsec, sec) != 0)
1305 continue;
1306 if (!is_valid_name(elf, sym))
1307 continue;
1308 if (sym->st_value <= addr) {
1309 if ((addr - sym->st_value) < distance) {
1310 distance = addr - sym->st_value;
1311 near = sym;
1312 } else if ((addr - sym->st_value) == distance) {
1313 near = sym;
1314 }
1315 }
1316 }
1317 return near;
1318 }
1319
1320 /*
1321 * Convert a section name to the function/data attribute
1322 * .init.text => __init
1323 * .memexitconst => __memconst
1324 * etc.
1325 *
1326 * The memory of returned value has been allocated on a heap. The user of this
1327 * method should free it after usage.
1328 */
1329 static char *sec2annotation(const char *s)
1330 {
1331 if (match(s, init_exit_sections)) {
1332 char *p = malloc(20);
1333 char *r = p;
1334
1335 *p++ = '_';
1336 *p++ = '_';
1337 if (*s == '.')
1338 s++;
1339 while (*s && *s != '.')
1340 *p++ = *s++;
1341 *p = '\0';
1342 if (*s == '.')
1343 s++;
1344 if (strstr(s, "rodata") != NULL)
1345 strcat(p, "const ");
1346 else if (strstr(s, "data") != NULL)
1347 strcat(p, "data ");
1348 else
1349 strcat(p, " ");
1350 return r;
1351 } else {
1352 return strdup("");
1353 }
1354 }
1355
1356 static int is_function(Elf_Sym *sym)
1357 {
1358 if (sym)
1359 return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1360 else
1361 return -1;
1362 }
1363
1364 static void print_section_list(const char * const list[20])
1365 {
1366 const char *const *s = list;
1367
1368 while (*s) {
1369 fprintf(stderr, "%s", *s);
1370 s++;
1371 if (*s)
1372 fprintf(stderr, ", ");
1373 }
1374 fprintf(stderr, "\n");
1375 }
1376
1377 static inline void get_pretty_name(int is_func, const char** name, const char** name_p)
1378 {
1379 switch (is_func) {
1380 case 0: *name = "variable"; *name_p = ""; break;
1381 case 1: *name = "function"; *name_p = "()"; break;
1382 default: *name = "(unknown reference)"; *name_p = ""; break;
1383 }
1384 }
1385
1386 /*
1387 * Print a warning about a section mismatch.
1388 * Try to find symbols near it so user can find it.
1389 * Check whitelist before warning - it may be a false positive.
1390 */
1391 static void report_sec_mismatch(const char *modname,
1392 const struct sectioncheck *mismatch,
1393 const char *fromsec,
1394 unsigned long long fromaddr,
1395 const char *fromsym,
1396 int from_is_func,
1397 const char *tosec, const char *tosym,
1398 int to_is_func)
1399 {
1400 const char *from, *from_p;
1401 const char *to, *to_p;
1402 char *prl_from;
1403 char *prl_to;
1404
1405 sec_mismatch_count++;
1406 if (!sec_mismatch_verbose)
1407 return;
1408
1409 get_pretty_name(from_is_func, &from, &from_p);
1410 get_pretty_name(to_is_func, &to, &to_p);
1411
1412 warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1413 "to the %s %s:%s%s\n",
1414 modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1415 tosym, to_p);
1416
1417 switch (mismatch->mismatch) {
1418 case TEXT_TO_ANY_INIT:
1419 prl_from = sec2annotation(fromsec);
1420 prl_to = sec2annotation(tosec);
1421 fprintf(stderr,
1422 "The function %s%s() references\n"
1423 "the %s %s%s%s.\n"
1424 "This is often because %s lacks a %s\n"
1425 "annotation or the annotation of %s is wrong.\n",
1426 prl_from, fromsym,
1427 to, prl_to, tosym, to_p,
1428 fromsym, prl_to, tosym);
1429 free(prl_from);
1430 free(prl_to);
1431 break;
1432 case DATA_TO_ANY_INIT: {
1433 prl_to = sec2annotation(tosec);
1434 fprintf(stderr,
1435 "The variable %s references\n"
1436 "the %s %s%s%s\n"
1437 "If the reference is valid then annotate the\n"
1438 "variable with __init* or __refdata (see linux/init.h) "
1439 "or name the variable:\n",
1440 fromsym, to, prl_to, tosym, to_p);
1441 print_section_list(mismatch->symbol_white_list);
1442 free(prl_to);
1443 break;
1444 }
1445 case TEXT_TO_ANY_EXIT:
1446 prl_to = sec2annotation(tosec);
1447 fprintf(stderr,
1448 "The function %s() references a %s in an exit section.\n"
1449 "Often the %s %s%s has valid usage outside the exit section\n"
1450 "and the fix is to remove the %sannotation of %s.\n",
1451 fromsym, to, to, tosym, to_p, prl_to, tosym);
1452 free(prl_to);
1453 break;
1454 case DATA_TO_ANY_EXIT: {
1455 prl_to = sec2annotation(tosec);
1456 fprintf(stderr,
1457 "The variable %s references\n"
1458 "the %s %s%s%s\n"
1459 "If the reference is valid then annotate the\n"
1460 "variable with __exit* (see linux/init.h) or "
1461 "name the variable:\n",
1462 fromsym, to, prl_to, tosym, to_p);
1463 print_section_list(mismatch->symbol_white_list);
1464 free(prl_to);
1465 break;
1466 }
1467 case XXXINIT_TO_SOME_INIT:
1468 case XXXEXIT_TO_SOME_EXIT:
1469 prl_from = sec2annotation(fromsec);
1470 prl_to = sec2annotation(tosec);
1471 fprintf(stderr,
1472 "The %s %s%s%s references\n"
1473 "a %s %s%s%s.\n"
1474 "If %s is only used by %s then\n"
1475 "annotate %s with a matching annotation.\n",
1476 from, prl_from, fromsym, from_p,
1477 to, prl_to, tosym, to_p,
1478 tosym, fromsym, tosym);
1479 free(prl_from);
1480 free(prl_to);
1481 break;
1482 case ANY_INIT_TO_ANY_EXIT:
1483 prl_from = sec2annotation(fromsec);
1484 prl_to = sec2annotation(tosec);
1485 fprintf(stderr,
1486 "The %s %s%s%s references\n"
1487 "a %s %s%s%s.\n"
1488 "This is often seen when error handling "
1489 "in the init function\n"
1490 "uses functionality in the exit path.\n"
1491 "The fix is often to remove the %sannotation of\n"
1492 "%s%s so it may be used outside an exit section.\n",
1493 from, prl_from, fromsym, from_p,
1494 to, prl_to, tosym, to_p,
1495 prl_to, tosym, to_p);
1496 free(prl_from);
1497 free(prl_to);
1498 break;
1499 case ANY_EXIT_TO_ANY_INIT:
1500 prl_from = sec2annotation(fromsec);
1501 prl_to = sec2annotation(tosec);
1502 fprintf(stderr,
1503 "The %s %s%s%s references\n"
1504 "a %s %s%s%s.\n"
1505 "This is often seen when error handling "
1506 "in the exit function\n"
1507 "uses functionality in the init path.\n"
1508 "The fix is often to remove the %sannotation of\n"
1509 "%s%s so it may be used outside an init section.\n",
1510 from, prl_from, fromsym, from_p,
1511 to, prl_to, tosym, to_p,
1512 prl_to, tosym, to_p);
1513 free(prl_from);
1514 free(prl_to);
1515 break;
1516 case EXPORT_TO_INIT_EXIT:
1517 prl_to = sec2annotation(tosec);
1518 fprintf(stderr,
1519 "The symbol %s is exported and annotated %s\n"
1520 "Fix this by removing the %sannotation of %s "
1521 "or drop the export.\n",
1522 tosym, prl_to, prl_to, tosym);
1523 free(prl_to);
1524 break;
1525 case EXTABLE_TO_NON_TEXT:
1526 fatal("There's a special handler for this mismatch type, "
1527 "we should never get here.");
1528 break;
1529 }
1530 fprintf(stderr, "\n");
1531 }
1532
1533 static void default_mismatch_handler(const char *modname, struct elf_info *elf,
1534 const struct sectioncheck* const mismatch,
1535 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1536 {
1537 const char *tosec;
1538 Elf_Sym *to;
1539 Elf_Sym *from;
1540 const char *tosym;
1541 const char *fromsym;
1542
1543 from = find_elf_symbol2(elf, r->r_offset, fromsec);
1544 fromsym = sym_name(elf, from);
1545
1546 if (!strncmp(fromsym, "reference___initcall",
1547 sizeof("reference___initcall")-1))
1548 return;
1549
1550 tosec = sec_name(elf, get_secindex(elf, sym));
1551 to = find_elf_symbol(elf, r->r_addend, sym);
1552 tosym = sym_name(elf, to);
1553
1554 /* check whitelist - we may ignore it */
1555 if (secref_whitelist(mismatch,
1556 fromsec, fromsym, tosec, tosym)) {
1557 report_sec_mismatch(modname, mismatch,
1558 fromsec, r->r_offset, fromsym,
1559 is_function(from), tosec, tosym,
1560 is_function(to));
1561 }
1562 }
1563
1564 static int is_executable_section(struct elf_info* elf, unsigned int section_index)
1565 {
1566 if (section_index > elf->num_sections)
1567 fatal("section_index is outside elf->num_sections!\n");
1568
1569 return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR);
1570 }
1571
1572 /*
1573 * We rely on a gross hack in section_rel[a]() calling find_extable_entry_size()
1574 * to know the sizeof(struct exception_table_entry) for the target architecture.
1575 */
1576 static unsigned int extable_entry_size = 0;
1577 static void find_extable_entry_size(const char* const sec, const Elf_Rela* r)
1578 {
1579 /*
1580 * If we're currently checking the second relocation within __ex_table,
1581 * that relocation offset tells us the offsetof(struct
1582 * exception_table_entry, fixup) which is equal to sizeof(struct
1583 * exception_table_entry) divided by two. We use that to our advantage
1584 * since there's no portable way to get that size as every architecture
1585 * seems to go with different sized types. Not pretty but better than
1586 * hard-coding the size for every architecture..
1587 */
1588 if (!extable_entry_size)
1589 extable_entry_size = r->r_offset * 2;
1590 }
1591
1592 static inline bool is_extable_fault_address(Elf_Rela *r)
1593 {
1594 /*
1595 * extable_entry_size is only discovered after we've handled the
1596 * _second_ relocation in __ex_table, so only abort when we're not
1597 * handling the first reloc and extable_entry_size is zero.
1598 */
1599 if (r->r_offset && extable_entry_size == 0)
1600 fatal("extable_entry size hasn't been discovered!\n");
1601
1602 return ((r->r_offset == 0) ||
1603 (r->r_offset % extable_entry_size == 0));
1604 }
1605
1606 #define is_second_extable_reloc(Start, Cur, Sec) \
1607 (((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0))
1608
1609 static void report_extable_warnings(const char* modname, struct elf_info* elf,
1610 const struct sectioncheck* const mismatch,
1611 Elf_Rela* r, Elf_Sym* sym,
1612 const char* fromsec, const char* tosec)
1613 {
1614 Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec);
1615 const char* fromsym_name = sym_name(elf, fromsym);
1616 Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym);
1617 const char* tosym_name = sym_name(elf, tosym);
1618 const char* from_pretty_name;
1619 const char* from_pretty_name_p;
1620 const char* to_pretty_name;
1621 const char* to_pretty_name_p;
1622
1623 get_pretty_name(is_function(fromsym),
1624 &from_pretty_name, &from_pretty_name_p);
1625 get_pretty_name(is_function(tosym),
1626 &to_pretty_name, &to_pretty_name_p);
1627
1628 warn("%s(%s+0x%lx): Section mismatch in reference"
1629 " from the %s %s%s to the %s %s:%s%s\n",
1630 modname, fromsec, (long)r->r_offset, from_pretty_name,
1631 fromsym_name, from_pretty_name_p,
1632 to_pretty_name, tosec, tosym_name, to_pretty_name_p);
1633
1634 if (!match(tosec, mismatch->bad_tosec) &&
1635 is_executable_section(elf, get_secindex(elf, sym)))
1636 fprintf(stderr,
1637 "The relocation at %s+0x%lx references\n"
1638 "section \"%s\" which is not in the list of\n"
1639 "authorized sections. If you're adding a new section\n"
1640 "and/or if this reference is valid, add \"%s\" to the\n"
1641 "list of authorized sections to jump to on fault.\n"
1642 "This can be achieved by adding \"%s\" to \n"
1643 "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
1644 fromsec, (long)r->r_offset, tosec, tosec, tosec);
1645 }
1646
1647 static void extable_mismatch_handler(const char* modname, struct elf_info *elf,
1648 const struct sectioncheck* const mismatch,
1649 Elf_Rela* r, Elf_Sym* sym,
1650 const char *fromsec)
1651 {
1652 const char* tosec = sec_name(elf, get_secindex(elf, sym));
1653
1654 sec_mismatch_count++;
1655
1656 if (sec_mismatch_verbose)
1657 report_extable_warnings(modname, elf, mismatch, r, sym,
1658 fromsec, tosec);
1659
1660 if (match(tosec, mismatch->bad_tosec))
1661 fatal("The relocation at %s+0x%lx references\n"
1662 "section \"%s\" which is black-listed.\n"
1663 "Something is seriously wrong and should be fixed.\n"
1664 "You might get more information about where this is\n"
1665 "coming from by using scripts/check_extable.sh %s\n",
1666 fromsec, (long)r->r_offset, tosec, modname);
1667 else if (!is_executable_section(elf, get_secindex(elf, sym))) {
1668 if (is_extable_fault_address(r))
1669 fatal("The relocation at %s+0x%lx references\n"
1670 "section \"%s\" which is not executable, IOW\n"
1671 "it is not possible for the kernel to fault\n"
1672 "at that address. Something is seriously wrong\n"
1673 "and should be fixed.\n",
1674 fromsec, (long)r->r_offset, tosec);
1675 else
1676 fatal("The relocation at %s+0x%lx references\n"
1677 "section \"%s\" which is not executable, IOW\n"
1678 "the kernel will fault if it ever tries to\n"
1679 "jump to it. Something is seriously wrong\n"
1680 "and should be fixed.\n",
1681 fromsec, (long)r->r_offset, tosec);
1682 }
1683 }
1684
1685 static void check_section_mismatch(const char *modname, struct elf_info *elf,
1686 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1687 {
1688 const char *tosec = sec_name(elf, get_secindex(elf, sym));
1689 const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec);
1690
1691 if (mismatch) {
1692 if (mismatch->handler)
1693 mismatch->handler(modname, elf, mismatch,
1694 r, sym, fromsec);
1695 else
1696 default_mismatch_handler(modname, elf, mismatch,
1697 r, sym, fromsec);
1698 }
1699 }
1700
1701 static unsigned int *reloc_location(struct elf_info *elf,
1702 Elf_Shdr *sechdr, Elf_Rela *r)
1703 {
1704 Elf_Shdr *sechdrs = elf->sechdrs;
1705 int section = sechdr->sh_info;
1706
1707 return (void *)elf->hdr + sechdrs[section].sh_offset +
1708 r->r_offset;
1709 }
1710
1711 static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1712 {
1713 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1714 unsigned int *location = reloc_location(elf, sechdr, r);
1715
1716 switch (r_typ) {
1717 case R_386_32:
1718 r->r_addend = TO_NATIVE(*location);
1719 break;
1720 case R_386_PC32:
1721 r->r_addend = TO_NATIVE(*location) + 4;
1722 /* For CONFIG_RELOCATABLE=y */
1723 if (elf->hdr->e_type == ET_EXEC)
1724 r->r_addend += r->r_offset;
1725 break;
1726 }
1727 return 0;
1728 }
1729
1730 #ifndef R_ARM_CALL
1731 #define R_ARM_CALL 28
1732 #endif
1733 #ifndef R_ARM_JUMP24
1734 #define R_ARM_JUMP24 29
1735 #endif
1736
1737 #ifndef R_ARM_THM_CALL
1738 #define R_ARM_THM_CALL 10
1739 #endif
1740 #ifndef R_ARM_THM_JUMP24
1741 #define R_ARM_THM_JUMP24 30
1742 #endif
1743 #ifndef R_ARM_THM_JUMP19
1744 #define R_ARM_THM_JUMP19 51
1745 #endif
1746
1747 static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1748 {
1749 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1750
1751 switch (r_typ) {
1752 case R_ARM_ABS32:
1753 /* From ARM ABI: (S + A) | T */
1754 r->r_addend = (int)(long)
1755 (elf->symtab_start + ELF_R_SYM(r->r_info));
1756 break;
1757 case R_ARM_PC24:
1758 case R_ARM_CALL:
1759 case R_ARM_JUMP24:
1760 case R_ARM_THM_CALL:
1761 case R_ARM_THM_JUMP24:
1762 case R_ARM_THM_JUMP19:
1763 /* From ARM ABI: ((S + A) | T) - P */
1764 r->r_addend = (int)(long)(elf->hdr +
1765 sechdr->sh_offset +
1766 (r->r_offset - sechdr->sh_addr));
1767 break;
1768 default:
1769 return 1;
1770 }
1771 return 0;
1772 }
1773
1774 static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1775 {
1776 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1777 unsigned int *location = reloc_location(elf, sechdr, r);
1778 unsigned int inst;
1779
1780 if (r_typ == R_MIPS_HI16)
1781 return 1; /* skip this */
1782 inst = TO_NATIVE(*location);
1783 switch (r_typ) {
1784 case R_MIPS_LO16:
1785 r->r_addend = inst & 0xffff;
1786 break;
1787 case R_MIPS_26:
1788 r->r_addend = (inst & 0x03ffffff) << 2;
1789 break;
1790 case R_MIPS_32:
1791 r->r_addend = inst;
1792 break;
1793 }
1794 return 0;
1795 }
1796
1797 static void section_rela(const char *modname, struct elf_info *elf,
1798 Elf_Shdr *sechdr)
1799 {
1800 Elf_Sym *sym;
1801 Elf_Rela *rela;
1802 Elf_Rela r;
1803 unsigned int r_sym;
1804 const char *fromsec;
1805
1806 Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1807 Elf_Rela *stop = (void *)start + sechdr->sh_size;
1808
1809 fromsec = sech_name(elf, sechdr);
1810 fromsec += strlen(".rela");
1811 /* if from section (name) is know good then skip it */
1812 if (match(fromsec, section_white_list))
1813 return;
1814
1815 for (rela = start; rela < stop; rela++) {
1816 r.r_offset = TO_NATIVE(rela->r_offset);
1817 #if KERNEL_ELFCLASS == ELFCLASS64
1818 if (elf->hdr->e_machine == EM_MIPS) {
1819 unsigned int r_typ;
1820 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1821 r_sym = TO_NATIVE(r_sym);
1822 r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1823 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1824 } else {
1825 r.r_info = TO_NATIVE(rela->r_info);
1826 r_sym = ELF_R_SYM(r.r_info);
1827 }
1828 #else
1829 r.r_info = TO_NATIVE(rela->r_info);
1830 r_sym = ELF_R_SYM(r.r_info);
1831 #endif
1832 r.r_addend = TO_NATIVE(rela->r_addend);
1833 sym = elf->symtab_start + r_sym;
1834 /* Skip special sections */
1835 if (is_shndx_special(sym->st_shndx))
1836 continue;
1837 if (is_second_extable_reloc(start, rela, fromsec))
1838 find_extable_entry_size(fromsec, &r);
1839 check_section_mismatch(modname, elf, &r, sym, fromsec);
1840 }
1841 }
1842
1843 static void section_rel(const char *modname, struct elf_info *elf,
1844 Elf_Shdr *sechdr)
1845 {
1846 Elf_Sym *sym;
1847 Elf_Rel *rel;
1848 Elf_Rela r;
1849 unsigned int r_sym;
1850 const char *fromsec;
1851
1852 Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1853 Elf_Rel *stop = (void *)start + sechdr->sh_size;
1854
1855 fromsec = sech_name(elf, sechdr);
1856 fromsec += strlen(".rel");
1857 /* if from section (name) is know good then skip it */
1858 if (match(fromsec, section_white_list))
1859 return;
1860
1861 for (rel = start; rel < stop; rel++) {
1862 r.r_offset = TO_NATIVE(rel->r_offset);
1863 #if KERNEL_ELFCLASS == ELFCLASS64
1864 if (elf->hdr->e_machine == EM_MIPS) {
1865 unsigned int r_typ;
1866 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1867 r_sym = TO_NATIVE(r_sym);
1868 r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1869 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1870 } else {
1871 r.r_info = TO_NATIVE(rel->r_info);
1872 r_sym = ELF_R_SYM(r.r_info);
1873 }
1874 #else
1875 r.r_info = TO_NATIVE(rel->r_info);
1876 r_sym = ELF_R_SYM(r.r_info);
1877 #endif
1878 r.r_addend = 0;
1879 switch (elf->hdr->e_machine) {
1880 case EM_386:
1881 if (addend_386_rel(elf, sechdr, &r))
1882 continue;
1883 break;
1884 case EM_ARM:
1885 if (addend_arm_rel(elf, sechdr, &r))
1886 continue;
1887 break;
1888 case EM_MIPS:
1889 if (addend_mips_rel(elf, sechdr, &r))
1890 continue;
1891 break;
1892 }
1893 sym = elf->symtab_start + r_sym;
1894 /* Skip special sections */
1895 if (is_shndx_special(sym->st_shndx))
1896 continue;
1897 if (is_second_extable_reloc(start, rel, fromsec))
1898 find_extable_entry_size(fromsec, &r);
1899 check_section_mismatch(modname, elf, &r, sym, fromsec);
1900 }
1901 }
1902
1903 /**
1904 * A module includes a number of sections that are discarded
1905 * either when loaded or when used as built-in.
1906 * For loaded modules all functions marked __init and all data
1907 * marked __initdata will be discarded when the module has been initialized.
1908 * Likewise for modules used built-in the sections marked __exit
1909 * are discarded because __exit marked function are supposed to be called
1910 * only when a module is unloaded which never happens for built-in modules.
1911 * The check_sec_ref() function traverses all relocation records
1912 * to find all references to a section that reference a section that will
1913 * be discarded and warns about it.
1914 **/
1915 static void check_sec_ref(struct module *mod, const char *modname,
1916 struct elf_info *elf)
1917 {
1918 int i;
1919 Elf_Shdr *sechdrs = elf->sechdrs;
1920
1921 /* Walk through all sections */
1922 for (i = 0; i < elf->num_sections; i++) {
1923 check_section(modname, elf, &elf->sechdrs[i]);
1924 /* We want to process only relocation sections and not .init */
1925 if (sechdrs[i].sh_type == SHT_RELA)
1926 section_rela(modname, elf, &elf->sechdrs[i]);
1927 else if (sechdrs[i].sh_type == SHT_REL)
1928 section_rel(modname, elf, &elf->sechdrs[i]);
1929 }
1930 }
1931
1932 static char *remove_dot(char *s)
1933 {
1934 size_t n = strcspn(s, ".");
1935
1936 if (n && s[n]) {
1937 size_t m = strspn(s + n + 1, "0123456789");
1938 if (m && (s[n + m] == '.' || s[n + m] == 0))
1939 s[n] = 0;
1940 }
1941 return s;
1942 }
1943
1944 static void read_symbols(char *modname)
1945 {
1946 const char *symname;
1947 char *version;
1948 char *license;
1949 struct module *mod;
1950 struct elf_info info = { };
1951 Elf_Sym *sym;
1952
1953 if (!parse_elf(&info, modname))
1954 return;
1955
1956 mod = new_module(modname);
1957
1958 /* When there's no vmlinux, don't print warnings about
1959 * unresolved symbols (since there'll be too many ;) */
1960 if (is_vmlinux(modname)) {
1961 have_vmlinux = 1;
1962 mod->skip = 1;
1963 }
1964
1965 license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1966 if (!license && !is_vmlinux(modname))
1967 warn("modpost: missing MODULE_LICENSE() in %s\n"
1968 "see include/linux/module.h for "
1969 "more information\n", modname);
1970 while (license) {
1971 if (license_is_gpl_compatible(license))
1972 mod->gpl_compatible = 1;
1973 else {
1974 mod->gpl_compatible = 0;
1975 break;
1976 }
1977 license = get_next_modinfo(info.modinfo, info.modinfo_len,
1978 "license", license);
1979 }
1980
1981 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1982 symname = remove_dot(info.strtab + sym->st_name);
1983
1984 handle_modversions(mod, &info, sym, symname);
1985 handle_moddevtable(mod, &info, sym, symname);
1986 }
1987 if (!is_vmlinux(modname) ||
1988 (is_vmlinux(modname) && vmlinux_section_warnings))
1989 check_sec_ref(mod, modname, &info);
1990
1991 version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1992 if (version)
1993 maybe_frob_rcs_version(modname, version, info.modinfo,
1994 version - (char *)info.hdr);
1995 if (version || (all_versions && !is_vmlinux(modname)))
1996 get_src_version(modname, mod->srcversion,
1997 sizeof(mod->srcversion)-1);
1998
1999 parse_elf_finish(&info);
2000
2001 /* Our trick to get versioning for module struct etc. - it's
2002 * never passed as an argument to an exported function, so
2003 * the automatic versioning doesn't pick it up, but it's really
2004 * important anyhow */
2005 if (modversions)
2006 mod->unres = alloc_symbol("module_layout", 0, mod->unres);
2007 }
2008
2009 static void read_symbols_from_files(const char *filename)
2010 {
2011 FILE *in = stdin;
2012 char fname[PATH_MAX];
2013
2014 if (strcmp(filename, "-") != 0) {
2015 in = fopen(filename, "r");
2016 if (!in)
2017 fatal("Can't open filenames file %s: %m", filename);
2018 }
2019
2020 while (fgets(fname, PATH_MAX, in) != NULL) {
2021 if (strends(fname, "\n"))
2022 fname[strlen(fname)-1] = '\0';
2023 read_symbols(fname);
2024 }
2025
2026 if (in != stdin)
2027 fclose(in);
2028 }
2029
2030 #define SZ 500
2031
2032 /* We first write the generated file into memory using the
2033 * following helper, then compare to the file on disk and
2034 * only update the later if anything changed */
2035
2036 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
2037 const char *fmt, ...)
2038 {
2039 char tmp[SZ];
2040 int len;
2041 va_list ap;
2042
2043 va_start(ap, fmt);
2044 len = vsnprintf(tmp, SZ, fmt, ap);
2045 buf_write(buf, tmp, len);
2046 va_end(ap);
2047 }
2048
2049 void buf_write(struct buffer *buf, const char *s, int len)
2050 {
2051 if (buf->size - buf->pos < len) {
2052 buf->size += len + SZ;
2053 buf->p = realloc(buf->p, buf->size);
2054 }
2055 strncpy(buf->p + buf->pos, s, len);
2056 buf->pos += len;
2057 }
2058
2059 static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
2060 {
2061 const char *e = is_vmlinux(m) ?"":".ko";
2062
2063 switch (exp) {
2064 case export_gpl:
2065 fatal("modpost: GPL-incompatible module %s%s "
2066 "uses GPL-only symbol '%s'\n", m, e, s);
2067 break;
2068 case export_unused_gpl:
2069 fatal("modpost: GPL-incompatible module %s%s "
2070 "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
2071 break;
2072 case export_gpl_future:
2073 warn("modpost: GPL-incompatible module %s%s "
2074 "uses future GPL-only symbol '%s'\n", m, e, s);
2075 break;
2076 case export_plain:
2077 case export_unused:
2078 case export_unknown:
2079 /* ignore */
2080 break;
2081 }
2082 }
2083
2084 static void check_for_unused(enum export exp, const char *m, const char *s)
2085 {
2086 const char *e = is_vmlinux(m) ?"":".ko";
2087
2088 switch (exp) {
2089 case export_unused:
2090 case export_unused_gpl:
2091 warn("modpost: module %s%s "
2092 "uses symbol '%s' marked UNUSED\n", m, e, s);
2093 break;
2094 default:
2095 /* ignore */
2096 break;
2097 }
2098 }
2099
2100 static void check_exports(struct module *mod)
2101 {
2102 struct symbol *s, *exp;
2103
2104 for (s = mod->unres; s; s = s->next) {
2105 const char *basename;
2106 exp = find_symbol(s->name);
2107 if (!exp || exp->module == mod)
2108 continue;
2109 basename = strrchr(mod->name, '/');
2110 if (basename)
2111 basename++;
2112 else
2113 basename = mod->name;
2114 if (!mod->gpl_compatible)
2115 check_for_gpl_usage(exp->export, basename, exp->name);
2116 check_for_unused(exp->export, basename, exp->name);
2117 }
2118 }
2119
2120 static int check_modname_len(struct module *mod)
2121 {
2122 const char *mod_name;
2123
2124 mod_name = strrchr(mod->name, '/');
2125 if (mod_name == NULL)
2126 mod_name = mod->name;
2127 else
2128 mod_name++;
2129 if (strlen(mod_name) >= MODULE_NAME_LEN) {
2130 merror("module name is too long [%s.ko]\n", mod->name);
2131 return 1;
2132 }
2133
2134 return 0;
2135 }
2136
2137 /**
2138 * Header for the generated file
2139 **/
2140 static void add_header(struct buffer *b, struct module *mod)
2141 {
2142 buf_printf(b, "#include <linux/module.h>\n");
2143 buf_printf(b, "#include <linux/vermagic.h>\n");
2144 buf_printf(b, "#include <linux/compiler.h>\n");
2145 buf_printf(b, "\n");
2146 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
2147 buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n");
2148 buf_printf(b, "\n");
2149 buf_printf(b, "__visible struct module __this_module\n");
2150 buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
2151 buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
2152 if (mod->has_init)
2153 buf_printf(b, "\t.init = init_module,\n");
2154 if (mod->has_cleanup)
2155 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
2156 "\t.exit = cleanup_module,\n"
2157 "#endif\n");
2158 buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
2159 buf_printf(b, "};\n");
2160 }
2161
2162 static void add_intree_flag(struct buffer *b, int is_intree)
2163 {
2164 if (is_intree)
2165 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
2166 }
2167
2168 /* Cannot check for assembler */
2169 static void add_retpoline(struct buffer *b)
2170 {
2171 buf_printf(b, "\n#ifdef RETPOLINE\n");
2172 buf_printf(b, "MODULE_INFO(retpoline, \"Y\");\n");
2173 buf_printf(b, "#endif\n");
2174 }
2175
2176 static void add_staging_flag(struct buffer *b, const char *name)
2177 {
2178 static const char *staging_dir = "drivers/staging";
2179
2180 if (strncmp(staging_dir, name, strlen(staging_dir)) == 0)
2181 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
2182 }
2183
2184 /**
2185 * Record CRCs for unresolved symbols
2186 **/
2187 static int add_versions(struct buffer *b, struct module *mod)
2188 {
2189 struct symbol *s, *exp;
2190 int err = 0;
2191
2192 for (s = mod->unres; s; s = s->next) {
2193 exp = find_symbol(s->name);
2194 if (!exp || exp->module == mod) {
2195 if (have_vmlinux && !s->weak) {
2196 if (warn_unresolved) {
2197 warn("\"%s\" [%s.ko] undefined!\n",
2198 s->name, mod->name);
2199 } else {
2200 merror("\"%s\" [%s.ko] undefined!\n",
2201 s->name, mod->name);
2202 err = 1;
2203 }
2204 }
2205 continue;
2206 }
2207 s->module = exp->module;
2208 s->crc_valid = exp->crc_valid;
2209 s->crc = exp->crc;
2210 }
2211
2212 if (!modversions)
2213 return err;
2214
2215 buf_printf(b, "\n");
2216 buf_printf(b, "static const struct modversion_info ____versions[]\n");
2217 buf_printf(b, "__used\n");
2218 buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
2219
2220 for (s = mod->unres; s; s = s->next) {
2221 if (!s->module)
2222 continue;
2223 if (!s->crc_valid) {
2224 warn("\"%s\" [%s.ko] has no CRC!\n",
2225 s->name, mod->name);
2226 continue;
2227 }
2228 if (strlen(s->name) >= MODULE_NAME_LEN) {
2229 merror("too long symbol \"%s\" [%s.ko]\n",
2230 s->name, mod->name);
2231 err = 1;
2232 break;
2233 }
2234 buf_printf(b, "\t{ %#8x, __VMLINUX_SYMBOL_STR(%s) },\n",
2235 s->crc, s->name);
2236 }
2237
2238 buf_printf(b, "};\n");
2239
2240 return err;
2241 }
2242
2243 static void add_depends(struct buffer *b, struct module *mod,
2244 struct module *modules)
2245 {
2246 struct symbol *s;
2247 struct module *m;
2248 int first = 1;
2249
2250 for (m = modules; m; m = m->next)
2251 m->seen = is_vmlinux(m->name);
2252
2253 buf_printf(b, "\n");
2254 buf_printf(b, "static const char __module_depends[]\n");
2255 buf_printf(b, "__used\n");
2256 buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
2257 buf_printf(b, "\"depends=");
2258 for (s = mod->unres; s; s = s->next) {
2259 const char *p;
2260 if (!s->module)
2261 continue;
2262
2263 if (s->module->seen)
2264 continue;
2265
2266 s->module->seen = 1;
2267 p = strrchr(s->module->name, '/');
2268 if (p)
2269 p++;
2270 else
2271 p = s->module->name;
2272 buf_printf(b, "%s%s", first ? "" : ",", p);
2273 first = 0;
2274 }
2275 buf_printf(b, "\";\n");
2276 }
2277
2278 static void add_srcversion(struct buffer *b, struct module *mod)
2279 {
2280 if (mod->srcversion[0]) {
2281 buf_printf(b, "\n");
2282 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
2283 mod->srcversion);
2284 }
2285 }
2286
2287 static void write_if_changed(struct buffer *b, const char *fname)
2288 {
2289 char *tmp;
2290 FILE *file;
2291 struct stat st;
2292
2293 file = fopen(fname, "r");
2294 if (!file)
2295 goto write;
2296
2297 if (fstat(fileno(file), &st) < 0)
2298 goto close_write;
2299
2300 if (st.st_size != b->pos)
2301 goto close_write;
2302
2303 tmp = NOFAIL(malloc(b->pos));
2304 if (fread(tmp, 1, b->pos, file) != b->pos)
2305 goto free_write;
2306
2307 if (memcmp(tmp, b->p, b->pos) != 0)
2308 goto free_write;
2309
2310 free(tmp);
2311 fclose(file);
2312 return;
2313
2314 free_write:
2315 free(tmp);
2316 close_write:
2317 fclose(file);
2318 write:
2319 file = fopen(fname, "w");
2320 if (!file) {
2321 perror(fname);
2322 exit(1);
2323 }
2324 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
2325 perror(fname);
2326 exit(1);
2327 }
2328 fclose(file);
2329 }
2330
2331 /* parse Module.symvers file. line format:
2332 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
2333 **/
2334 static void read_dump(const char *fname, unsigned int kernel)
2335 {
2336 unsigned long size, pos = 0;
2337 void *file = grab_file(fname, &size);
2338 char *line;
2339
2340 if (!file)
2341 /* No symbol versions, silently ignore */
2342 return;
2343
2344 while ((line = get_next_line(&pos, file, size))) {
2345 char *symname, *modname, *d, *export, *end;
2346 unsigned int crc;
2347 struct module *mod;
2348 struct symbol *s;
2349
2350 if (!(symname = strchr(line, '\t')))
2351 goto fail;
2352 *symname++ = '\0';
2353 if (!(modname = strchr(symname, '\t')))
2354 goto fail;
2355 *modname++ = '\0';
2356 if ((export = strchr(modname, '\t')) != NULL)
2357 *export++ = '\0';
2358 if (export && ((end = strchr(export, '\t')) != NULL))
2359 *end = '\0';
2360 crc = strtoul(line, &d, 16);
2361 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2362 goto fail;
2363 mod = find_module(modname);
2364 if (!mod) {
2365 if (is_vmlinux(modname))
2366 have_vmlinux = 1;
2367 mod = new_module(modname);
2368 mod->skip = 1;
2369 }
2370 s = sym_add_exported(symname, mod, export_no(export));
2371 s->kernel = kernel;
2372 s->preloaded = 1;
2373 sym_update_crc(symname, mod, crc, export_no(export));
2374 }
2375 release_file(file, size);
2376 return;
2377 fail:
2378 release_file(file, size);
2379 fatal("parse error in symbol dump file\n");
2380 }
2381
2382 /* For normal builds always dump all symbols.
2383 * For external modules only dump symbols
2384 * that are not read from kernel Module.symvers.
2385 **/
2386 static int dump_sym(struct symbol *sym)
2387 {
2388 if (!external_module)
2389 return 1;
2390 if (sym->vmlinux || sym->kernel)
2391 return 0;
2392 return 1;
2393 }
2394
2395 static void write_dump(const char *fname)
2396 {
2397 struct buffer buf = { };
2398 struct symbol *symbol;
2399 int n;
2400
2401 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
2402 symbol = symbolhash[n];
2403 while (symbol) {
2404 if (dump_sym(symbol))
2405 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
2406 symbol->crc, symbol->name,
2407 symbol->module->name,
2408 export_str(symbol->export));
2409 symbol = symbol->next;
2410 }
2411 }
2412 write_if_changed(&buf, fname);
2413 free(buf.p);
2414 }
2415
2416 struct ext_sym_list {
2417 struct ext_sym_list *next;
2418 const char *file;
2419 };
2420
2421 int main(int argc, char **argv)
2422 {
2423 struct module *mod;
2424 struct buffer buf = { };
2425 char *kernel_read = NULL, *module_read = NULL;
2426 char *dump_write = NULL, *files_source = NULL;
2427 int opt;
2428 int err;
2429 struct ext_sym_list *extsym_iter;
2430 struct ext_sym_list *extsym_start = NULL;
2431
2432 while ((opt = getopt(argc, argv, "i:I:e:mnsST:o:awM:K:E")) != -1) {
2433 switch (opt) {
2434 case 'i':
2435 kernel_read = optarg;
2436 break;
2437 case 'I':
2438 module_read = optarg;
2439 external_module = 1;
2440 break;
2441 case 'e':
2442 external_module = 1;
2443 extsym_iter =
2444 NOFAIL(malloc(sizeof(*extsym_iter)));
2445 extsym_iter->next = extsym_start;
2446 extsym_iter->file = optarg;
2447 extsym_start = extsym_iter;
2448 break;
2449 case 'm':
2450 modversions = 1;
2451 break;
2452 case 'n':
2453 ignore_missing_files = 1;
2454 break;
2455 case 'o':
2456 dump_write = optarg;
2457 break;
2458 case 'a':
2459 all_versions = 1;
2460 break;
2461 case 's':
2462 vmlinux_section_warnings = 0;
2463 break;
2464 case 'S':
2465 sec_mismatch_verbose = 0;
2466 break;
2467 case 'T':
2468 files_source = optarg;
2469 break;
2470 case 'w':
2471 warn_unresolved = 1;
2472 break;
2473 case 'E':
2474 sec_mismatch_fatal = 1;
2475 break;
2476 default:
2477 exit(1);
2478 }
2479 }
2480
2481 if (kernel_read)
2482 read_dump(kernel_read, 1);
2483 if (module_read)
2484 read_dump(module_read, 0);
2485 while (extsym_start) {
2486 read_dump(extsym_start->file, 0);
2487 extsym_iter = extsym_start->next;
2488 free(extsym_start);
2489 extsym_start = extsym_iter;
2490 }
2491
2492 while (optind < argc)
2493 read_symbols(argv[optind++]);
2494
2495 if (files_source)
2496 read_symbols_from_files(files_source);
2497
2498 for (mod = modules; mod; mod = mod->next) {
2499 if (mod->skip)
2500 continue;
2501 check_exports(mod);
2502 }
2503
2504 err = 0;
2505
2506 for (mod = modules; mod; mod = mod->next) {
2507 char fname[PATH_MAX];
2508
2509 if (mod->skip)
2510 continue;
2511
2512 buf.pos = 0;
2513
2514 err |= check_modname_len(mod);
2515 add_header(&buf, mod);
2516 add_intree_flag(&buf, !external_module);
2517 add_retpoline(&buf);
2518 add_staging_flag(&buf, mod->name);
2519 err |= add_versions(&buf, mod);
2520 add_depends(&buf, mod, modules);
2521 add_moddevtable(&buf, mod);
2522 add_srcversion(&buf, mod);
2523
2524 sprintf(fname, "%s.mod.c", mod->name);
2525 write_if_changed(&buf, fname);
2526 }
2527 if (dump_write)
2528 write_dump(dump_write);
2529 if (sec_mismatch_count) {
2530 if (!sec_mismatch_verbose) {
2531 warn("modpost: Found %d section mismatch(es).\n"
2532 "To see full details build your kernel with:\n"
2533 "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n",
2534 sec_mismatch_count);
2535 }
2536 if (sec_mismatch_fatal) {
2537 fatal("modpost: Section mismatches detected.\n"
2538 "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");
2539 }
2540 }
2541 free(buf.p);
2542
2543 return err;
2544 }
Linux with added FPC-III support