xref: /openbmc/linux/scripts/mod/modpost.c (revision 78c99ba1)
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 "modpost.h"
18 #include "../../include/linux/license.h"
19 
20 /* Are we using CONFIG_MODVERSIONS? */
21 int modversions = 0;
22 /* Warn about undefined symbols? (do so if we have vmlinux) */
23 int have_vmlinux = 0;
24 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */
25 static int all_versions = 0;
26 /* If we are modposting external module set to 1 */
27 static int external_module = 0;
28 /* Warn about section mismatch in vmlinux if set to 1 */
29 static int vmlinux_section_warnings = 1;
30 /* Only warn about unresolved symbols */
31 static int warn_unresolved = 0;
32 /* How a symbol is exported */
33 static int sec_mismatch_count = 0;
34 static int sec_mismatch_verbose = 1;
35 
36 enum export {
37 	export_plain,      export_unused,     export_gpl,
38 	export_unused_gpl, export_gpl_future, export_unknown
39 };
40 
41 #define PRINTF __attribute__ ((format (printf, 1, 2)))
42 
43 PRINTF void fatal(const char *fmt, ...)
44 {
45 	va_list arglist;
46 
47 	fprintf(stderr, "FATAL: ");
48 
49 	va_start(arglist, fmt);
50 	vfprintf(stderr, fmt, arglist);
51 	va_end(arglist);
52 
53 	exit(1);
54 }
55 
56 PRINTF void warn(const char *fmt, ...)
57 {
58 	va_list arglist;
59 
60 	fprintf(stderr, "WARNING: ");
61 
62 	va_start(arglist, fmt);
63 	vfprintf(stderr, fmt, arglist);
64 	va_end(arglist);
65 }
66 
67 PRINTF void merror(const char *fmt, ...)
68 {
69 	va_list arglist;
70 
71 	fprintf(stderr, "ERROR: ");
72 
73 	va_start(arglist, fmt);
74 	vfprintf(stderr, fmt, arglist);
75 	va_end(arglist);
76 }
77 
78 static int is_vmlinux(const char *modname)
79 {
80 	const char *myname;
81 
82 	myname = strrchr(modname, '/');
83 	if (myname)
84 		myname++;
85 	else
86 		myname = modname;
87 
88 	return (strcmp(myname, "vmlinux") == 0) ||
89 	       (strcmp(myname, "vmlinux.o") == 0);
90 }
91 
92 void *do_nofail(void *ptr, const char *expr)
93 {
94 	if (!ptr)
95 		fatal("modpost: Memory allocation failure: %s.\n", expr);
96 
97 	return ptr;
98 }
99 
100 /* A list of all modules we processed */
101 static struct module *modules;
102 
103 static struct module *find_module(char *modname)
104 {
105 	struct module *mod;
106 
107 	for (mod = modules; mod; mod = mod->next)
108 		if (strcmp(mod->name, modname) == 0)
109 			break;
110 	return mod;
111 }
112 
113 static struct module *new_module(char *modname)
114 {
115 	struct module *mod;
116 	char *p, *s;
117 
118 	mod = NOFAIL(malloc(sizeof(*mod)));
119 	memset(mod, 0, sizeof(*mod));
120 	p = NOFAIL(strdup(modname));
121 
122 	/* strip trailing .o */
123 	s = strrchr(p, '.');
124 	if (s != NULL)
125 		if (strcmp(s, ".o") == 0)
126 			*s = '\0';
127 
128 	/* add to list */
129 	mod->name = p;
130 	mod->gpl_compatible = -1;
131 	mod->next = modules;
132 	modules = mod;
133 
134 	return mod;
135 }
136 
137 /* A hash of all exported symbols,
138  * struct symbol is also used for lists of unresolved symbols */
139 
140 #define SYMBOL_HASH_SIZE 1024
141 
142 struct symbol {
143 	struct symbol *next;
144 	struct module *module;
145 	unsigned int crc;
146 	int crc_valid;
147 	unsigned int weak:1;
148 	unsigned int vmlinux:1;    /* 1 if symbol is defined in vmlinux */
149 	unsigned int kernel:1;     /* 1 if symbol is from kernel
150 				    *  (only for external modules) **/
151 	unsigned int preloaded:1;  /* 1 if symbol from Module.symvers */
152 	enum export  export;       /* Type of export */
153 	char name[0];
154 };
155 
156 static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
157 
158 /* This is based on the hash agorithm from gdbm, via tdb */
159 static inline unsigned int tdb_hash(const char *name)
160 {
161 	unsigned value;	/* Used to compute the hash value.  */
162 	unsigned   i;	/* Used to cycle through random values. */
163 
164 	/* Set the initial value from the key size. */
165 	for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
166 		value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
167 
168 	return (1103515243 * value + 12345);
169 }
170 
171 /**
172  * Allocate a new symbols for use in the hash of exported symbols or
173  * the list of unresolved symbols per module
174  **/
175 static struct symbol *alloc_symbol(const char *name, unsigned int weak,
176 				   struct symbol *next)
177 {
178 	struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
179 
180 	memset(s, 0, sizeof(*s));
181 	strcpy(s->name, name);
182 	s->weak = weak;
183 	s->next = next;
184 	return s;
185 }
186 
187 /* For the hash of exported symbols */
188 static struct symbol *new_symbol(const char *name, struct module *module,
189 				 enum export export)
190 {
191 	unsigned int hash;
192 	struct symbol *new;
193 
194 	hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
195 	new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
196 	new->module = module;
197 	new->export = export;
198 	return new;
199 }
200 
201 static struct symbol *find_symbol(const char *name)
202 {
203 	struct symbol *s;
204 
205 	/* For our purposes, .foo matches foo.  PPC64 needs this. */
206 	if (name[0] == '.')
207 		name++;
208 
209 	for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
210 		if (strcmp(s->name, name) == 0)
211 			return s;
212 	}
213 	return NULL;
214 }
215 
216 static struct {
217 	const char *str;
218 	enum export export;
219 } export_list[] = {
220 	{ .str = "EXPORT_SYMBOL",            .export = export_plain },
221 	{ .str = "EXPORT_UNUSED_SYMBOL",     .export = export_unused },
222 	{ .str = "EXPORT_SYMBOL_GPL",        .export = export_gpl },
223 	{ .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
224 	{ .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
225 	{ .str = "(unknown)",                .export = export_unknown },
226 };
227 
228 
229 static const char *export_str(enum export ex)
230 {
231 	return export_list[ex].str;
232 }
233 
234 static enum export export_no(const char *s)
235 {
236 	int i;
237 
238 	if (!s)
239 		return export_unknown;
240 	for (i = 0; export_list[i].export != export_unknown; i++) {
241 		if (strcmp(export_list[i].str, s) == 0)
242 			return export_list[i].export;
243 	}
244 	return export_unknown;
245 }
246 
247 static enum export export_from_sec(struct elf_info *elf, Elf_Section sec)
248 {
249 	if (sec == elf->export_sec)
250 		return export_plain;
251 	else if (sec == elf->export_unused_sec)
252 		return export_unused;
253 	else if (sec == elf->export_gpl_sec)
254 		return export_gpl;
255 	else if (sec == elf->export_unused_gpl_sec)
256 		return export_unused_gpl;
257 	else if (sec == elf->export_gpl_future_sec)
258 		return export_gpl_future;
259 	else
260 		return export_unknown;
261 }
262 
263 /**
264  * Add an exported symbol - it may have already been added without a
265  * CRC, in this case just update the CRC
266  **/
267 static struct symbol *sym_add_exported(const char *name, struct module *mod,
268 				       enum export export)
269 {
270 	struct symbol *s = find_symbol(name);
271 
272 	if (!s) {
273 		s = new_symbol(name, mod, export);
274 	} else {
275 		if (!s->preloaded) {
276 			warn("%s: '%s' exported twice. Previous export "
277 			     "was in %s%s\n", mod->name, name,
278 			     s->module->name,
279 			     is_vmlinux(s->module->name) ?"":".ko");
280 		} else {
281 			/* In case Modules.symvers was out of date */
282 			s->module = mod;
283 		}
284 	}
285 	s->preloaded = 0;
286 	s->vmlinux   = is_vmlinux(mod->name);
287 	s->kernel    = 0;
288 	s->export    = export;
289 	return s;
290 }
291 
292 static void sym_update_crc(const char *name, struct module *mod,
293 			   unsigned int crc, enum export export)
294 {
295 	struct symbol *s = find_symbol(name);
296 
297 	if (!s)
298 		s = new_symbol(name, mod, export);
299 	s->crc = crc;
300 	s->crc_valid = 1;
301 }
302 
303 void *grab_file(const char *filename, unsigned long *size)
304 {
305 	struct stat st;
306 	void *map;
307 	int fd;
308 
309 	fd = open(filename, O_RDONLY);
310 	if (fd < 0 || fstat(fd, &st) != 0)
311 		return NULL;
312 
313 	*size = st.st_size;
314 	map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
315 	close(fd);
316 
317 	if (map == MAP_FAILED)
318 		return NULL;
319 	return map;
320 }
321 
322 /**
323   * Return a copy of the next line in a mmap'ed file.
324   * spaces in the beginning of the line is trimmed away.
325   * Return a pointer to a static buffer.
326   **/
327 char *get_next_line(unsigned long *pos, void *file, unsigned long size)
328 {
329 	static char line[4096];
330 	int skip = 1;
331 	size_t len = 0;
332 	signed char *p = (signed char *)file + *pos;
333 	char *s = line;
334 
335 	for (; *pos < size ; (*pos)++) {
336 		if (skip && isspace(*p)) {
337 			p++;
338 			continue;
339 		}
340 		skip = 0;
341 		if (*p != '\n' && (*pos < size)) {
342 			len++;
343 			*s++ = *p++;
344 			if (len > 4095)
345 				break; /* Too long, stop */
346 		} else {
347 			/* End of string */
348 			*s = '\0';
349 			return line;
350 		}
351 	}
352 	/* End of buffer */
353 	return NULL;
354 }
355 
356 void release_file(void *file, unsigned long size)
357 {
358 	munmap(file, size);
359 }
360 
361 static int parse_elf(struct elf_info *info, const char *filename)
362 {
363 	unsigned int i;
364 	Elf_Ehdr *hdr;
365 	Elf_Shdr *sechdrs;
366 	Elf_Sym  *sym;
367 
368 	hdr = grab_file(filename, &info->size);
369 	if (!hdr) {
370 		perror(filename);
371 		exit(1);
372 	}
373 	info->hdr = hdr;
374 	if (info->size < sizeof(*hdr)) {
375 		/* file too small, assume this is an empty .o file */
376 		return 0;
377 	}
378 	/* Is this a valid ELF file? */
379 	if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
380 	    (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
381 	    (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
382 	    (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
383 		/* Not an ELF file - silently ignore it */
384 		return 0;
385 	}
386 	/* Fix endianness in ELF header */
387 	hdr->e_type      = TO_NATIVE(hdr->e_type);
388 	hdr->e_machine   = TO_NATIVE(hdr->e_machine);
389 	hdr->e_version   = TO_NATIVE(hdr->e_version);
390 	hdr->e_entry     = TO_NATIVE(hdr->e_entry);
391 	hdr->e_phoff     = TO_NATIVE(hdr->e_phoff);
392 	hdr->e_shoff     = TO_NATIVE(hdr->e_shoff);
393 	hdr->e_flags     = TO_NATIVE(hdr->e_flags);
394 	hdr->e_ehsize    = TO_NATIVE(hdr->e_ehsize);
395 	hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
396 	hdr->e_phnum     = TO_NATIVE(hdr->e_phnum);
397 	hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
398 	hdr->e_shnum     = TO_NATIVE(hdr->e_shnum);
399 	hdr->e_shstrndx  = TO_NATIVE(hdr->e_shstrndx);
400 	sechdrs = (void *)hdr + hdr->e_shoff;
401 	info->sechdrs = sechdrs;
402 
403 	/* Check if file offset is correct */
404 	if (hdr->e_shoff > info->size) {
405 		fatal("section header offset=%lu in file '%s' is bigger than "
406 		      "filesize=%lu\n", (unsigned long)hdr->e_shoff,
407 		      filename, info->size);
408 		return 0;
409 	}
410 
411 	/* Fix endianness in section headers */
412 	for (i = 0; i < hdr->e_shnum; i++) {
413 		sechdrs[i].sh_name      = TO_NATIVE(sechdrs[i].sh_name);
414 		sechdrs[i].sh_type      = TO_NATIVE(sechdrs[i].sh_type);
415 		sechdrs[i].sh_flags     = TO_NATIVE(sechdrs[i].sh_flags);
416 		sechdrs[i].sh_addr      = TO_NATIVE(sechdrs[i].sh_addr);
417 		sechdrs[i].sh_offset    = TO_NATIVE(sechdrs[i].sh_offset);
418 		sechdrs[i].sh_size      = TO_NATIVE(sechdrs[i].sh_size);
419 		sechdrs[i].sh_link      = TO_NATIVE(sechdrs[i].sh_link);
420 		sechdrs[i].sh_info      = TO_NATIVE(sechdrs[i].sh_info);
421 		sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
422 		sechdrs[i].sh_entsize   = TO_NATIVE(sechdrs[i].sh_entsize);
423 	}
424 	/* Find symbol table. */
425 	for (i = 1; i < hdr->e_shnum; i++) {
426 		const char *secstrings
427 			= (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
428 		const char *secname;
429 		int nobits = sechdrs[i].sh_type == SHT_NOBITS;
430 
431 		if (!nobits && sechdrs[i].sh_offset > info->size) {
432 			fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
433 			      "sizeof(*hrd)=%zu\n", filename,
434 			      (unsigned long)sechdrs[i].sh_offset,
435 			      sizeof(*hdr));
436 			return 0;
437 		}
438 		secname = secstrings + sechdrs[i].sh_name;
439 		if (strcmp(secname, ".modinfo") == 0) {
440 			if (nobits)
441 				fatal("%s has NOBITS .modinfo\n", filename);
442 			info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
443 			info->modinfo_len = sechdrs[i].sh_size;
444 		} else if (strcmp(secname, "__ksymtab") == 0)
445 			info->export_sec = i;
446 		else if (strcmp(secname, "__ksymtab_unused") == 0)
447 			info->export_unused_sec = i;
448 		else if (strcmp(secname, "__ksymtab_gpl") == 0)
449 			info->export_gpl_sec = i;
450 		else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
451 			info->export_unused_gpl_sec = i;
452 		else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
453 			info->export_gpl_future_sec = i;
454 		else if (strcmp(secname, "__markers_strings") == 0)
455 			info->markers_strings_sec = i;
456 
457 		if (sechdrs[i].sh_type != SHT_SYMTAB)
458 			continue;
459 
460 		info->symtab_start = (void *)hdr + sechdrs[i].sh_offset;
461 		info->symtab_stop  = (void *)hdr + sechdrs[i].sh_offset
462 			                         + sechdrs[i].sh_size;
463 		info->strtab       = (void *)hdr +
464 			             sechdrs[sechdrs[i].sh_link].sh_offset;
465 	}
466 	if (!info->symtab_start)
467 		fatal("%s has no symtab?\n", filename);
468 
469 	/* Fix endianness in symbols */
470 	for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
471 		sym->st_shndx = TO_NATIVE(sym->st_shndx);
472 		sym->st_name  = TO_NATIVE(sym->st_name);
473 		sym->st_value = TO_NATIVE(sym->st_value);
474 		sym->st_size  = TO_NATIVE(sym->st_size);
475 	}
476 	return 1;
477 }
478 
479 static void parse_elf_finish(struct elf_info *info)
480 {
481 	release_file(info->hdr, info->size);
482 }
483 
484 static int ignore_undef_symbol(struct elf_info *info, const char *symname)
485 {
486 	/* ignore __this_module, it will be resolved shortly */
487 	if (strcmp(symname, MODULE_SYMBOL_PREFIX "__this_module") == 0)
488 		return 1;
489 	/* ignore global offset table */
490 	if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
491 		return 1;
492 	if (info->hdr->e_machine == EM_PPC)
493 		/* Special register function linked on all modules during final link of .ko */
494 		if (strncmp(symname, "_restgpr_", sizeof("_restgpr_") - 1) == 0 ||
495 		    strncmp(symname, "_savegpr_", sizeof("_savegpr_") - 1) == 0 ||
496 		    strncmp(symname, "_rest32gpr_", sizeof("_rest32gpr_") - 1) == 0 ||
497 		    strncmp(symname, "_save32gpr_", sizeof("_save32gpr_") - 1) == 0)
498 			return 1;
499 	/* Do not ignore this symbol */
500 	return 0;
501 }
502 
503 #define CRC_PFX     MODULE_SYMBOL_PREFIX "__crc_"
504 #define KSYMTAB_PFX MODULE_SYMBOL_PREFIX "__ksymtab_"
505 
506 static void handle_modversions(struct module *mod, struct elf_info *info,
507 			       Elf_Sym *sym, const char *symname)
508 {
509 	unsigned int crc;
510 	enum export export = export_from_sec(info, sym->st_shndx);
511 
512 	switch (sym->st_shndx) {
513 	case SHN_COMMON:
514 		warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
515 		break;
516 	case SHN_ABS:
517 		/* CRC'd symbol */
518 		if (memcmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
519 			crc = (unsigned int) sym->st_value;
520 			sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
521 					export);
522 		}
523 		break;
524 	case SHN_UNDEF:
525 		/* undefined symbol */
526 		if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
527 		    ELF_ST_BIND(sym->st_info) != STB_WEAK)
528 			break;
529 		if (ignore_undef_symbol(info, symname))
530 			break;
531 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
532 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
533 /* add compatibility with older glibc */
534 #ifndef STT_SPARC_REGISTER
535 #define STT_SPARC_REGISTER STT_REGISTER
536 #endif
537 		if (info->hdr->e_machine == EM_SPARC ||
538 		    info->hdr->e_machine == EM_SPARCV9) {
539 			/* Ignore register directives. */
540 			if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
541 				break;
542 			if (symname[0] == '.') {
543 				char *munged = strdup(symname);
544 				munged[0] = '_';
545 				munged[1] = toupper(munged[1]);
546 				symname = munged;
547 			}
548 		}
549 #endif
550 
551 		if (memcmp(symname, MODULE_SYMBOL_PREFIX,
552 			   strlen(MODULE_SYMBOL_PREFIX)) == 0) {
553 			mod->unres =
554 			  alloc_symbol(symname +
555 			               strlen(MODULE_SYMBOL_PREFIX),
556 			               ELF_ST_BIND(sym->st_info) == STB_WEAK,
557 			               mod->unres);
558 		}
559 		break;
560 	default:
561 		/* All exported symbols */
562 		if (memcmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
563 			sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
564 					export);
565 		}
566 		if (strcmp(symname, MODULE_SYMBOL_PREFIX "init_module") == 0)
567 			mod->has_init = 1;
568 		if (strcmp(symname, MODULE_SYMBOL_PREFIX "cleanup_module") == 0)
569 			mod->has_cleanup = 1;
570 		break;
571 	}
572 }
573 
574 /**
575  * Parse tag=value strings from .modinfo section
576  **/
577 static char *next_string(char *string, unsigned long *secsize)
578 {
579 	/* Skip non-zero chars */
580 	while (string[0]) {
581 		string++;
582 		if ((*secsize)-- <= 1)
583 			return NULL;
584 	}
585 
586 	/* Skip any zero padding. */
587 	while (!string[0]) {
588 		string++;
589 		if ((*secsize)-- <= 1)
590 			return NULL;
591 	}
592 	return string;
593 }
594 
595 static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
596 			      const char *tag, char *info)
597 {
598 	char *p;
599 	unsigned int taglen = strlen(tag);
600 	unsigned long size = modinfo_len;
601 
602 	if (info) {
603 		size -= info - (char *)modinfo;
604 		modinfo = next_string(info, &size);
605 	}
606 
607 	for (p = modinfo; p; p = next_string(p, &size)) {
608 		if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
609 			return p + taglen + 1;
610 	}
611 	return NULL;
612 }
613 
614 static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
615 			 const char *tag)
616 
617 {
618 	return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
619 }
620 
621 /**
622  * Test if string s ends in string sub
623  * return 0 if match
624  **/
625 static int strrcmp(const char *s, const char *sub)
626 {
627 	int slen, sublen;
628 
629 	if (!s || !sub)
630 		return 1;
631 
632 	slen = strlen(s);
633 	sublen = strlen(sub);
634 
635 	if ((slen == 0) || (sublen == 0))
636 		return 1;
637 
638 	if (sublen > slen)
639 		return 1;
640 
641 	return memcmp(s + slen - sublen, sub, sublen);
642 }
643 
644 static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
645 {
646 	if (sym)
647 		return elf->strtab + sym->st_name;
648 	else
649 		return "(unknown)";
650 }
651 
652 static const char *sec_name(struct elf_info *elf, int shndx)
653 {
654 	Elf_Shdr *sechdrs = elf->sechdrs;
655 	return (void *)elf->hdr +
656 	        elf->sechdrs[elf->hdr->e_shstrndx].sh_offset +
657 	        sechdrs[shndx].sh_name;
658 }
659 
660 static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr)
661 {
662 	return (void *)elf->hdr +
663 	        elf->sechdrs[elf->hdr->e_shstrndx].sh_offset +
664 	        sechdr->sh_name;
665 }
666 
667 /* if sym is empty or point to a string
668  * like ".[0-9]+" then return 1.
669  * This is the optional prefix added by ld to some sections
670  */
671 static int number_prefix(const char *sym)
672 {
673 	if (*sym++ == '\0')
674 		return 1;
675 	if (*sym != '.')
676 		return 0;
677 	do {
678 		char c = *sym++;
679 		if (c < '0' || c > '9')
680 			return 0;
681 	} while (*sym);
682 	return 1;
683 }
684 
685 /* The pattern is an array of simple patterns.
686  * "foo" will match an exact string equal to "foo"
687  * "*foo" will match a string that ends with "foo"
688  * "foo*" will match a string that begins with "foo"
689  * "foo$" will match a string equal to "foo" or "foo.1"
690  *   where the '1' can be any number including several digits.
691  *   The $ syntax is for sections where ld append a dot number
692  *   to make section name unique.
693  */
694 int match(const char *sym, const char * const pat[])
695 {
696 	const char *p;
697 	while (*pat) {
698 		p = *pat++;
699 		const char *endp = p + strlen(p) - 1;
700 
701 		/* "*foo" */
702 		if (*p == '*') {
703 			if (strrcmp(sym, p + 1) == 0)
704 				return 1;
705 		}
706 		/* "foo*" */
707 		else if (*endp == '*') {
708 			if (strncmp(sym, p, strlen(p) - 1) == 0)
709 				return 1;
710 		}
711 		/* "foo$" */
712 		else if (*endp == '$') {
713 			if (strncmp(sym, p, strlen(p) - 1) == 0) {
714 				if (number_prefix(sym + strlen(p) - 1))
715 					return 1;
716 			}
717 		}
718 		/* no wildcards */
719 		else {
720 			if (strcmp(p, sym) == 0)
721 				return 1;
722 		}
723 	}
724 	/* no match */
725 	return 0;
726 }
727 
728 /* sections that we do not want to do full section mismatch check on */
729 static const char *section_white_list[] =
730 {
731 	".comment*",
732 	".debug*",
733 	".mdebug*",        /* alpha, score, mips etc. */
734 	".pdr",            /* alpha, score, mips etc. */
735 	".stab*",
736 	".note*",
737 	".got*",
738 	".toc*",
739 	NULL
740 };
741 
742 /*
743  * This is used to find sections missing the SHF_ALLOC flag.
744  * The cause of this is often a section specified in assembler
745  * without "ax" / "aw".
746  */
747 static void check_section(const char *modname, struct elf_info *elf,
748                           Elf_Shdr *sechdr)
749 {
750 	const char *sec = sech_name(elf, sechdr);
751 
752 	if (sechdr->sh_type == SHT_PROGBITS &&
753 	    !(sechdr->sh_flags & SHF_ALLOC) &&
754 	    !match(sec, section_white_list)) {
755 		warn("%s (%s): unexpected non-allocatable section.\n"
756 		     "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
757 		     "Note that for example <linux/init.h> contains\n"
758 		     "section definitions for use in .S files.\n\n",
759 		     modname, sec);
760 	}
761 }
762 
763 
764 
765 #define ALL_INIT_DATA_SECTIONS \
766 	".init.data$", ".devinit.data$", ".cpuinit.data$", ".meminit.data$"
767 #define ALL_EXIT_DATA_SECTIONS \
768 	".exit.data$", ".devexit.data$", ".cpuexit.data$", ".memexit.data$"
769 
770 #define ALL_INIT_TEXT_SECTIONS \
771 	".init.text$", ".devinit.text$", ".cpuinit.text$", ".meminit.text$"
772 #define ALL_EXIT_TEXT_SECTIONS \
773 	".exit.text$", ".devexit.text$", ".cpuexit.text$", ".memexit.text$"
774 
775 #define ALL_INIT_SECTIONS ALL_INIT_DATA_SECTIONS, ALL_INIT_TEXT_SECTIONS
776 #define ALL_EXIT_SECTIONS ALL_EXIT_DATA_SECTIONS, ALL_EXIT_TEXT_SECTIONS
777 
778 #define DATA_SECTIONS ".data$", ".data.rel$"
779 #define TEXT_SECTIONS ".text$"
780 
781 #define INIT_SECTIONS      ".init.data$", ".init.text$"
782 #define DEV_INIT_SECTIONS  ".devinit.data$", ".devinit.text$"
783 #define CPU_INIT_SECTIONS  ".cpuinit.data$", ".cpuinit.text$"
784 #define MEM_INIT_SECTIONS  ".meminit.data$", ".meminit.text$"
785 
786 #define EXIT_SECTIONS      ".exit.data$", ".exit.text$"
787 #define DEV_EXIT_SECTIONS  ".devexit.data$", ".devexit.text$"
788 #define CPU_EXIT_SECTIONS  ".cpuexit.data$", ".cpuexit.text$"
789 #define MEM_EXIT_SECTIONS  ".memexit.data$", ".memexit.text$"
790 
791 /* init data sections */
792 static const char *init_data_sections[] = { ALL_INIT_DATA_SECTIONS, NULL };
793 
794 /* all init sections */
795 static const char *init_sections[] = { ALL_INIT_SECTIONS, NULL };
796 
797 /* All init and exit sections (code + data) */
798 static const char *init_exit_sections[] =
799 	{ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
800 
801 /* data section */
802 static const char *data_sections[] = { DATA_SECTIONS, NULL };
803 
804 
805 /* symbols in .data that may refer to init/exit sections */
806 static const char *symbol_white_list[] =
807 {
808 	"*driver",
809 	"*_template", /* scsi uses *_template a lot */
810 	"*_timer",    /* arm uses ops structures named _timer a lot */
811 	"*_sht",      /* scsi also used *_sht to some extent */
812 	"*_ops",
813 	"*_probe",
814 	"*_probe_one",
815 	"*_console",
816 	NULL
817 };
818 
819 static const char *head_sections[] = { ".head.text*", NULL };
820 static const char *linker_symbols[] =
821 	{ "__init_begin", "_sinittext", "_einittext", NULL };
822 
823 enum mismatch {
824 	NO_MISMATCH,
825 	TEXT_TO_INIT,
826 	DATA_TO_INIT,
827 	TEXT_TO_EXIT,
828 	DATA_TO_EXIT,
829 	XXXINIT_TO_INIT,
830 	XXXEXIT_TO_EXIT,
831 	INIT_TO_EXIT,
832 	EXIT_TO_INIT,
833 	EXPORT_TO_INIT_EXIT,
834 };
835 
836 struct sectioncheck {
837 	const char *fromsec[20];
838 	const char *tosec[20];
839 	enum mismatch mismatch;
840 };
841 
842 const struct sectioncheck sectioncheck[] = {
843 /* Do not reference init/exit code/data from
844  * normal code and data
845  */
846 {
847 	.fromsec = { TEXT_SECTIONS, NULL },
848 	.tosec   = { ALL_INIT_SECTIONS, NULL },
849 	.mismatch = TEXT_TO_INIT,
850 },
851 {
852 	.fromsec = { DATA_SECTIONS, NULL },
853 	.tosec   = { ALL_INIT_SECTIONS, NULL },
854 	.mismatch = DATA_TO_INIT,
855 },
856 {
857 	.fromsec = { TEXT_SECTIONS, NULL },
858 	.tosec   = { ALL_EXIT_SECTIONS, NULL },
859 	.mismatch = TEXT_TO_EXIT,
860 },
861 {
862 	.fromsec = { DATA_SECTIONS, NULL },
863 	.tosec   = { ALL_EXIT_SECTIONS, NULL },
864 	.mismatch = DATA_TO_EXIT,
865 },
866 /* Do not reference init code/data from devinit/cpuinit/meminit code/data */
867 {
868 	.fromsec = { DEV_INIT_SECTIONS, CPU_INIT_SECTIONS, MEM_INIT_SECTIONS, NULL },
869 	.tosec   = { INIT_SECTIONS, NULL },
870 	.mismatch = XXXINIT_TO_INIT,
871 },
872 /* Do not reference exit code/data from devexit/cpuexit/memexit code/data */
873 {
874 	.fromsec = { DEV_EXIT_SECTIONS, CPU_EXIT_SECTIONS, MEM_EXIT_SECTIONS, NULL },
875 	.tosec   = { EXIT_SECTIONS, NULL },
876 	.mismatch = XXXEXIT_TO_EXIT,
877 },
878 /* Do not use exit code/data from init code */
879 {
880 	.fromsec = { ALL_INIT_SECTIONS, NULL },
881 	.tosec   = { ALL_EXIT_SECTIONS, NULL },
882 	.mismatch = INIT_TO_EXIT,
883 },
884 /* Do not use init code/data from exit code */
885 {
886 	.fromsec = { ALL_EXIT_SECTIONS, NULL },
887 	.tosec   = { ALL_INIT_SECTIONS, NULL },
888 	.mismatch = EXIT_TO_INIT,
889 },
890 /* Do not export init/exit functions or data */
891 {
892 	.fromsec = { "__ksymtab*", NULL },
893 	.tosec   = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
894 	.mismatch = EXPORT_TO_INIT_EXIT
895 }
896 };
897 
898 static int section_mismatch(const char *fromsec, const char *tosec)
899 {
900 	int i;
901 	int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
902 	const struct sectioncheck *check = &sectioncheck[0];
903 
904 	for (i = 0; i < elems; i++) {
905 		if (match(fromsec, check->fromsec) &&
906 		    match(tosec, check->tosec))
907 			return check->mismatch;
908 		check++;
909 	}
910 	return NO_MISMATCH;
911 }
912 
913 /**
914  * Whitelist to allow certain references to pass with no warning.
915  *
916  * Pattern 1:
917  *   If a module parameter is declared __initdata and permissions=0
918  *   then this is legal despite the warning generated.
919  *   We cannot see value of permissions here, so just ignore
920  *   this pattern.
921  *   The pattern is identified by:
922  *   tosec   = .init.data
923  *   fromsec = .data*
924  *   atsym   =__param*
925  *
926  * Pattern 2:
927  *   Many drivers utilise a *driver container with references to
928  *   add, remove, probe functions etc.
929  *   These functions may often be marked __init and we do not want to
930  *   warn here.
931  *   the pattern is identified by:
932  *   tosec   = init or exit section
933  *   fromsec = data section
934  *   atsym = *driver, *_template, *_sht, *_ops, *_probe,
935  *           *probe_one, *_console, *_timer
936  *
937  * Pattern 3:
938  *   Whitelist all references from .head.text to any init section
939  *
940  * Pattern 4:
941  *   Some symbols belong to init section but still it is ok to reference
942  *   these from non-init sections as these symbols don't have any memory
943  *   allocated for them and symbol address and value are same. So even
944  *   if init section is freed, its ok to reference those symbols.
945  *   For ex. symbols marking the init section boundaries.
946  *   This pattern is identified by
947  *   refsymname = __init_begin, _sinittext, _einittext
948  *
949  **/
950 static int secref_whitelist(const char *fromsec, const char *fromsym,
951 			    const char *tosec, const char *tosym)
952 {
953 	/* Check for pattern 1 */
954 	if (match(tosec, init_data_sections) &&
955 	    match(fromsec, data_sections) &&
956 	    (strncmp(fromsym, "__param", strlen("__param")) == 0))
957 		return 0;
958 
959 	/* Check for pattern 2 */
960 	if (match(tosec, init_exit_sections) &&
961 	    match(fromsec, data_sections) &&
962 	    match(fromsym, symbol_white_list))
963 		return 0;
964 
965 	/* Check for pattern 3 */
966 	if (match(fromsec, head_sections) &&
967 	    match(tosec, init_sections))
968 		return 0;
969 
970 	/* Check for pattern 4 */
971 	if (match(tosym, linker_symbols))
972 		return 0;
973 
974 	return 1;
975 }
976 
977 /**
978  * Find symbol based on relocation record info.
979  * In some cases the symbol supplied is a valid symbol so
980  * return refsym. If st_name != 0 we assume this is a valid symbol.
981  * In other cases the symbol needs to be looked up in the symbol table
982  * based on section and address.
983  *  **/
984 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
985 				Elf_Sym *relsym)
986 {
987 	Elf_Sym *sym;
988 	Elf_Sym *near = NULL;
989 	Elf64_Sword distance = 20;
990 	Elf64_Sword d;
991 
992 	if (relsym->st_name != 0)
993 		return relsym;
994 	for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
995 		if (sym->st_shndx != relsym->st_shndx)
996 			continue;
997 		if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
998 			continue;
999 		if (sym->st_value == addr)
1000 			return sym;
1001 		/* Find a symbol nearby - addr are maybe negative */
1002 		d = sym->st_value - addr;
1003 		if (d < 0)
1004 			d = addr - sym->st_value;
1005 		if (d < distance) {
1006 			distance = d;
1007 			near = sym;
1008 		}
1009 	}
1010 	/* We need a close match */
1011 	if (distance < 20)
1012 		return near;
1013 	else
1014 		return NULL;
1015 }
1016 
1017 static inline int is_arm_mapping_symbol(const char *str)
1018 {
1019 	return str[0] == '$' && strchr("atd", str[1])
1020 	       && (str[2] == '\0' || str[2] == '.');
1021 }
1022 
1023 /*
1024  * If there's no name there, ignore it; likewise, ignore it if it's
1025  * one of the magic symbols emitted used by current ARM tools.
1026  *
1027  * Otherwise if find_symbols_between() returns those symbols, they'll
1028  * fail the whitelist tests and cause lots of false alarms ... fixable
1029  * only by merging __exit and __init sections into __text, bloating
1030  * the kernel (which is especially evil on embedded platforms).
1031  */
1032 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1033 {
1034 	const char *name = elf->strtab + sym->st_name;
1035 
1036 	if (!name || !strlen(name))
1037 		return 0;
1038 	return !is_arm_mapping_symbol(name);
1039 }
1040 
1041 /*
1042  * Find symbols before or equal addr and after addr - in the section sec.
1043  * If we find two symbols with equal offset prefer one with a valid name.
1044  * The ELF format may have a better way to detect what type of symbol
1045  * it is, but this works for now.
1046  **/
1047 static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1048 				 const char *sec)
1049 {
1050 	Elf_Sym *sym;
1051 	Elf_Sym *near = NULL;
1052 	Elf_Addr distance = ~0;
1053 
1054 	for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1055 		const char *symsec;
1056 
1057 		if (sym->st_shndx >= SHN_LORESERVE)
1058 			continue;
1059 		symsec = sec_name(elf, sym->st_shndx);
1060 		if (strcmp(symsec, sec) != 0)
1061 			continue;
1062 		if (!is_valid_name(elf, sym))
1063 			continue;
1064 		if (sym->st_value <= addr) {
1065 			if ((addr - sym->st_value) < distance) {
1066 				distance = addr - sym->st_value;
1067 				near = sym;
1068 			} else if ((addr - sym->st_value) == distance) {
1069 				near = sym;
1070 			}
1071 		}
1072 	}
1073 	return near;
1074 }
1075 
1076 /*
1077  * Convert a section name to the function/data attribute
1078  * .init.text => __init
1079  * .cpuinit.data => __cpudata
1080  * .memexitconst => __memconst
1081  * etc.
1082 */
1083 static char *sec2annotation(const char *s)
1084 {
1085 	if (match(s, init_exit_sections)) {
1086 		char *p = malloc(20);
1087 		char *r = p;
1088 
1089 		*p++ = '_';
1090 		*p++ = '_';
1091 		if (*s == '.')
1092 			s++;
1093 		while (*s && *s != '.')
1094 			*p++ = *s++;
1095 		*p = '\0';
1096 		if (*s == '.')
1097 			s++;
1098 		if (strstr(s, "rodata") != NULL)
1099 			strcat(p, "const ");
1100 		else if (strstr(s, "data") != NULL)
1101 			strcat(p, "data ");
1102 		else
1103 			strcat(p, " ");
1104 		return r; /* we leak her but we do not care */
1105 	} else {
1106 		return "";
1107 	}
1108 }
1109 
1110 static int is_function(Elf_Sym *sym)
1111 {
1112 	if (sym)
1113 		return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1114 	else
1115 		return -1;
1116 }
1117 
1118 /*
1119  * Print a warning about a section mismatch.
1120  * Try to find symbols near it so user can find it.
1121  * Check whitelist before warning - it may be a false positive.
1122  */
1123 static void report_sec_mismatch(const char *modname, enum mismatch mismatch,
1124                                 const char *fromsec,
1125                                 unsigned long long fromaddr,
1126                                 const char *fromsym,
1127                                 int from_is_func,
1128                                 const char *tosec, const char *tosym,
1129                                 int to_is_func)
1130 {
1131 	const char *from, *from_p;
1132 	const char *to, *to_p;
1133 
1134 	switch (from_is_func) {
1135 	case 0: from = "variable"; from_p = "";   break;
1136 	case 1: from = "function"; from_p = "()"; break;
1137 	default: from = "(unknown reference)"; from_p = ""; break;
1138 	}
1139 	switch (to_is_func) {
1140 	case 0: to = "variable"; to_p = "";   break;
1141 	case 1: to = "function"; to_p = "()"; break;
1142 	default: to = "(unknown reference)"; to_p = ""; break;
1143 	}
1144 
1145 	sec_mismatch_count++;
1146 	if (!sec_mismatch_verbose)
1147 		return;
1148 
1149 	warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1150 	     "to the %s %s:%s%s\n",
1151 	     modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1152 	     tosym, to_p);
1153 
1154 	switch (mismatch) {
1155 	case TEXT_TO_INIT:
1156 		fprintf(stderr,
1157 		"The function %s%s() references\n"
1158 		"the %s %s%s%s.\n"
1159 		"This is often because %s lacks a %s\n"
1160 		"annotation or the annotation of %s is wrong.\n",
1161 		sec2annotation(fromsec), fromsym,
1162 		to, sec2annotation(tosec), tosym, to_p,
1163 		fromsym, sec2annotation(tosec), tosym);
1164 		break;
1165 	case DATA_TO_INIT: {
1166 		const char **s = symbol_white_list;
1167 		fprintf(stderr,
1168 		"The variable %s references\n"
1169 		"the %s %s%s%s\n"
1170 		"If the reference is valid then annotate the\n"
1171 		"variable with __init* (see linux/init.h) "
1172 		"or name the variable:\n",
1173 		fromsym, to, sec2annotation(tosec), tosym, to_p);
1174 		while (*s)
1175 			fprintf(stderr, "%s, ", *s++);
1176 		fprintf(stderr, "\n");
1177 		break;
1178 	}
1179 	case TEXT_TO_EXIT:
1180 		fprintf(stderr,
1181 		"The function %s() references a %s in an exit section.\n"
1182 		"Often the %s %s%s has valid usage outside the exit section\n"
1183 		"and the fix is to remove the %sannotation of %s.\n",
1184 		fromsym, to, to, tosym, to_p, sec2annotation(tosec), tosym);
1185 		break;
1186 	case DATA_TO_EXIT: {
1187 		const char **s = symbol_white_list;
1188 		fprintf(stderr,
1189 		"The variable %s references\n"
1190 		"the %s %s%s%s\n"
1191 		"If the reference is valid then annotate the\n"
1192 		"variable with __exit* (see linux/init.h) or "
1193 		"name the variable:\n",
1194 		fromsym, to, sec2annotation(tosec), tosym, to_p);
1195 		while (*s)
1196 			fprintf(stderr, "%s, ", *s++);
1197 		fprintf(stderr, "\n");
1198 		break;
1199 	}
1200 	case XXXINIT_TO_INIT:
1201 	case XXXEXIT_TO_EXIT:
1202 		fprintf(stderr,
1203 		"The %s %s%s%s references\n"
1204 		"a %s %s%s%s.\n"
1205 		"If %s is only used by %s then\n"
1206 		"annotate %s with a matching annotation.\n",
1207 		from, sec2annotation(fromsec), fromsym, from_p,
1208 		to, sec2annotation(tosec), tosym, to_p,
1209 		tosym, fromsym, tosym);
1210 		break;
1211 	case INIT_TO_EXIT:
1212 		fprintf(stderr,
1213 		"The %s %s%s%s references\n"
1214 		"a %s %s%s%s.\n"
1215 		"This is often seen when error handling "
1216 		"in the init function\n"
1217 		"uses functionality in the exit path.\n"
1218 		"The fix is often to remove the %sannotation of\n"
1219 		"%s%s so it may be used outside an exit section.\n",
1220 		from, sec2annotation(fromsec), fromsym, from_p,
1221 		to, sec2annotation(tosec), tosym, to_p,
1222 		sec2annotation(tosec), tosym, to_p);
1223 		break;
1224 	case EXIT_TO_INIT:
1225 		fprintf(stderr,
1226 		"The %s %s%s%s references\n"
1227 		"a %s %s%s%s.\n"
1228 		"This is often seen when error handling "
1229 		"in the exit function\n"
1230 		"uses functionality in the init path.\n"
1231 		"The fix is often to remove the %sannotation of\n"
1232 		"%s%s so it may be used outside an init section.\n",
1233 		from, sec2annotation(fromsec), fromsym, from_p,
1234 		to, sec2annotation(tosec), tosym, to_p,
1235 		sec2annotation(tosec), tosym, to_p);
1236 		break;
1237 	case EXPORT_TO_INIT_EXIT:
1238 		fprintf(stderr,
1239 		"The symbol %s is exported and annotated %s\n"
1240 		"Fix this by removing the %sannotation of %s "
1241 		"or drop the export.\n",
1242 		tosym, sec2annotation(tosec), sec2annotation(tosec), tosym);
1243 	case NO_MISMATCH:
1244 		/* To get warnings on missing members */
1245 		break;
1246 	}
1247 	fprintf(stderr, "\n");
1248 }
1249 
1250 static void check_section_mismatch(const char *modname, struct elf_info *elf,
1251                                    Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1252 {
1253 	const char *tosec;
1254 	enum mismatch mismatch;
1255 
1256 	tosec = sec_name(elf, sym->st_shndx);
1257 	mismatch = section_mismatch(fromsec, tosec);
1258 	if (mismatch != NO_MISMATCH) {
1259 		Elf_Sym *to;
1260 		Elf_Sym *from;
1261 		const char *tosym;
1262 		const char *fromsym;
1263 
1264 		from = find_elf_symbol2(elf, r->r_offset, fromsec);
1265 		fromsym = sym_name(elf, from);
1266 		to = find_elf_symbol(elf, r->r_addend, sym);
1267 		tosym = sym_name(elf, to);
1268 
1269 		/* check whitelist - we may ignore it */
1270 		if (secref_whitelist(fromsec, fromsym, tosec, tosym)) {
1271 			report_sec_mismatch(modname, mismatch,
1272 			   fromsec, r->r_offset, fromsym,
1273 			   is_function(from), tosec, tosym,
1274 			   is_function(to));
1275 		}
1276 	}
1277 }
1278 
1279 static unsigned int *reloc_location(struct elf_info *elf,
1280 				    Elf_Shdr *sechdr, Elf_Rela *r)
1281 {
1282 	Elf_Shdr *sechdrs = elf->sechdrs;
1283 	int section = sechdr->sh_info;
1284 
1285 	return (void *)elf->hdr + sechdrs[section].sh_offset +
1286 		(r->r_offset - sechdrs[section].sh_addr);
1287 }
1288 
1289 static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1290 {
1291 	unsigned int r_typ = ELF_R_TYPE(r->r_info);
1292 	unsigned int *location = reloc_location(elf, sechdr, r);
1293 
1294 	switch (r_typ) {
1295 	case R_386_32:
1296 		r->r_addend = TO_NATIVE(*location);
1297 		break;
1298 	case R_386_PC32:
1299 		r->r_addend = TO_NATIVE(*location) + 4;
1300 		/* For CONFIG_RELOCATABLE=y */
1301 		if (elf->hdr->e_type == ET_EXEC)
1302 			r->r_addend += r->r_offset;
1303 		break;
1304 	}
1305 	return 0;
1306 }
1307 
1308 static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1309 {
1310 	unsigned int r_typ = ELF_R_TYPE(r->r_info);
1311 
1312 	switch (r_typ) {
1313 	case R_ARM_ABS32:
1314 		/* From ARM ABI: (S + A) | T */
1315 		r->r_addend = (int)(long)
1316 		              (elf->symtab_start + ELF_R_SYM(r->r_info));
1317 		break;
1318 	case R_ARM_PC24:
1319 		/* From ARM ABI: ((S + A) | T) - P */
1320 		r->r_addend = (int)(long)(elf->hdr +
1321 		              sechdr->sh_offset +
1322 		              (r->r_offset - sechdr->sh_addr));
1323 		break;
1324 	default:
1325 		return 1;
1326 	}
1327 	return 0;
1328 }
1329 
1330 static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1331 {
1332 	unsigned int r_typ = ELF_R_TYPE(r->r_info);
1333 	unsigned int *location = reloc_location(elf, sechdr, r);
1334 	unsigned int inst;
1335 
1336 	if (r_typ == R_MIPS_HI16)
1337 		return 1;	/* skip this */
1338 	inst = TO_NATIVE(*location);
1339 	switch (r_typ) {
1340 	case R_MIPS_LO16:
1341 		r->r_addend = inst & 0xffff;
1342 		break;
1343 	case R_MIPS_26:
1344 		r->r_addend = (inst & 0x03ffffff) << 2;
1345 		break;
1346 	case R_MIPS_32:
1347 		r->r_addend = inst;
1348 		break;
1349 	}
1350 	return 0;
1351 }
1352 
1353 static void section_rela(const char *modname, struct elf_info *elf,
1354                          Elf_Shdr *sechdr)
1355 {
1356 	Elf_Sym  *sym;
1357 	Elf_Rela *rela;
1358 	Elf_Rela r;
1359 	unsigned int r_sym;
1360 	const char *fromsec;
1361 
1362 	Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1363 	Elf_Rela *stop  = (void *)start + sechdr->sh_size;
1364 
1365 	fromsec = sech_name(elf, sechdr);
1366 	fromsec += strlen(".rela");
1367 	/* if from section (name) is know good then skip it */
1368 	if (match(fromsec, section_white_list))
1369 		return;
1370 
1371 	for (rela = start; rela < stop; rela++) {
1372 		r.r_offset = TO_NATIVE(rela->r_offset);
1373 #if KERNEL_ELFCLASS == ELFCLASS64
1374 		if (elf->hdr->e_machine == EM_MIPS) {
1375 			unsigned int r_typ;
1376 			r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1377 			r_sym = TO_NATIVE(r_sym);
1378 			r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1379 			r.r_info = ELF64_R_INFO(r_sym, r_typ);
1380 		} else {
1381 			r.r_info = TO_NATIVE(rela->r_info);
1382 			r_sym = ELF_R_SYM(r.r_info);
1383 		}
1384 #else
1385 		r.r_info = TO_NATIVE(rela->r_info);
1386 		r_sym = ELF_R_SYM(r.r_info);
1387 #endif
1388 		r.r_addend = TO_NATIVE(rela->r_addend);
1389 		sym = elf->symtab_start + r_sym;
1390 		/* Skip special sections */
1391 		if (sym->st_shndx >= SHN_LORESERVE)
1392 			continue;
1393 		check_section_mismatch(modname, elf, &r, sym, fromsec);
1394 	}
1395 }
1396 
1397 static void section_rel(const char *modname, struct elf_info *elf,
1398                         Elf_Shdr *sechdr)
1399 {
1400 	Elf_Sym *sym;
1401 	Elf_Rel *rel;
1402 	Elf_Rela r;
1403 	unsigned int r_sym;
1404 	const char *fromsec;
1405 
1406 	Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1407 	Elf_Rel *stop  = (void *)start + sechdr->sh_size;
1408 
1409 	fromsec = sech_name(elf, sechdr);
1410 	fromsec += strlen(".rel");
1411 	/* if from section (name) is know good then skip it */
1412 	if (match(fromsec, section_white_list))
1413 		return;
1414 
1415 	for (rel = start; rel < stop; rel++) {
1416 		r.r_offset = TO_NATIVE(rel->r_offset);
1417 #if KERNEL_ELFCLASS == ELFCLASS64
1418 		if (elf->hdr->e_machine == EM_MIPS) {
1419 			unsigned int r_typ;
1420 			r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1421 			r_sym = TO_NATIVE(r_sym);
1422 			r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1423 			r.r_info = ELF64_R_INFO(r_sym, r_typ);
1424 		} else {
1425 			r.r_info = TO_NATIVE(rel->r_info);
1426 			r_sym = ELF_R_SYM(r.r_info);
1427 		}
1428 #else
1429 		r.r_info = TO_NATIVE(rel->r_info);
1430 		r_sym = ELF_R_SYM(r.r_info);
1431 #endif
1432 		r.r_addend = 0;
1433 		switch (elf->hdr->e_machine) {
1434 		case EM_386:
1435 			if (addend_386_rel(elf, sechdr, &r))
1436 				continue;
1437 			break;
1438 		case EM_ARM:
1439 			if (addend_arm_rel(elf, sechdr, &r))
1440 				continue;
1441 			break;
1442 		case EM_MIPS:
1443 			if (addend_mips_rel(elf, sechdr, &r))
1444 				continue;
1445 			break;
1446 		}
1447 		sym = elf->symtab_start + r_sym;
1448 		/* Skip special sections */
1449 		if (sym->st_shndx >= SHN_LORESERVE)
1450 			continue;
1451 		check_section_mismatch(modname, elf, &r, sym, fromsec);
1452 	}
1453 }
1454 
1455 /**
1456  * A module includes a number of sections that are discarded
1457  * either when loaded or when used as built-in.
1458  * For loaded modules all functions marked __init and all data
1459  * marked __initdata will be discarded when the module has been intialized.
1460  * Likewise for modules used built-in the sections marked __exit
1461  * are discarded because __exit marked function are supposed to be called
1462  * only when a module is unloaded which never happens for built-in modules.
1463  * The check_sec_ref() function traverses all relocation records
1464  * to find all references to a section that reference a section that will
1465  * be discarded and warns about it.
1466  **/
1467 static void check_sec_ref(struct module *mod, const char *modname,
1468                           struct elf_info *elf)
1469 {
1470 	int i;
1471 	Elf_Shdr *sechdrs = elf->sechdrs;
1472 
1473 	/* Walk through all sections */
1474 	for (i = 0; i < elf->hdr->e_shnum; i++) {
1475 		check_section(modname, elf, &elf->sechdrs[i]);
1476 		/* We want to process only relocation sections and not .init */
1477 		if (sechdrs[i].sh_type == SHT_RELA)
1478 			section_rela(modname, elf, &elf->sechdrs[i]);
1479 		else if (sechdrs[i].sh_type == SHT_REL)
1480 			section_rel(modname, elf, &elf->sechdrs[i]);
1481 	}
1482 }
1483 
1484 static void get_markers(struct elf_info *info, struct module *mod)
1485 {
1486 	const Elf_Shdr *sh = &info->sechdrs[info->markers_strings_sec];
1487 	const char *strings = (const char *) info->hdr + sh->sh_offset;
1488 	const Elf_Sym *sym, *first_sym, *last_sym;
1489 	size_t n;
1490 
1491 	if (!info->markers_strings_sec)
1492 		return;
1493 
1494 	/*
1495 	 * First count the strings.  We look for all the symbols defined
1496 	 * in the __markers_strings section named __mstrtab_*.  For
1497 	 * these local names, the compiler puts a random .NNN suffix on,
1498 	 * so the names don't correspond exactly.
1499 	 */
1500 	first_sym = last_sym = NULL;
1501 	n = 0;
1502 	for (sym = info->symtab_start; sym < info->symtab_stop; sym++)
1503 		if (ELF_ST_TYPE(sym->st_info) == STT_OBJECT &&
1504 		    sym->st_shndx == info->markers_strings_sec &&
1505 		    !strncmp(info->strtab + sym->st_name,
1506 			     "__mstrtab_", sizeof "__mstrtab_" - 1)) {
1507 			if (first_sym == NULL)
1508 				first_sym = sym;
1509 			last_sym = sym;
1510 			++n;
1511 		}
1512 
1513 	if (n == 0)
1514 		return;
1515 
1516 	/*
1517 	 * Now collect each name and format into a line for the output.
1518 	 * Lines look like:
1519 	 *	marker_name	vmlinux	marker %s format %d
1520 	 * The format string after the second \t can use whitespace.
1521 	 */
1522 	mod->markers = NOFAIL(malloc(sizeof mod->markers[0] * n));
1523 	mod->nmarkers = n;
1524 
1525 	n = 0;
1526 	for (sym = first_sym; sym <= last_sym; sym++)
1527 		if (ELF_ST_TYPE(sym->st_info) == STT_OBJECT &&
1528 		    sym->st_shndx == info->markers_strings_sec &&
1529 		    !strncmp(info->strtab + sym->st_name,
1530 			     "__mstrtab_", sizeof "__mstrtab_" - 1)) {
1531 			const char *name = strings + sym->st_value;
1532 			const char *fmt = strchr(name, '\0') + 1;
1533 			char *line = NULL;
1534 			asprintf(&line, "%s\t%s\t%s\n", name, mod->name, fmt);
1535 			NOFAIL(line);
1536 			mod->markers[n++] = line;
1537 		}
1538 }
1539 
1540 static void read_symbols(char *modname)
1541 {
1542 	const char *symname;
1543 	char *version;
1544 	char *license;
1545 	struct module *mod;
1546 	struct elf_info info = { };
1547 	Elf_Sym *sym;
1548 
1549 	if (!parse_elf(&info, modname))
1550 		return;
1551 
1552 	mod = new_module(modname);
1553 
1554 	/* When there's no vmlinux, don't print warnings about
1555 	 * unresolved symbols (since there'll be too many ;) */
1556 	if (is_vmlinux(modname)) {
1557 		have_vmlinux = 1;
1558 		mod->skip = 1;
1559 	}
1560 
1561 	license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1562 	if (info.modinfo && !license && !is_vmlinux(modname))
1563 		warn("modpost: missing MODULE_LICENSE() in %s\n"
1564 		     "see include/linux/module.h for "
1565 		     "more information\n", modname);
1566 	while (license) {
1567 		if (license_is_gpl_compatible(license))
1568 			mod->gpl_compatible = 1;
1569 		else {
1570 			mod->gpl_compatible = 0;
1571 			break;
1572 		}
1573 		license = get_next_modinfo(info.modinfo, info.modinfo_len,
1574 					   "license", license);
1575 	}
1576 
1577 	for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1578 		symname = info.strtab + sym->st_name;
1579 
1580 		handle_modversions(mod, &info, sym, symname);
1581 		handle_moddevtable(mod, &info, sym, symname);
1582 	}
1583 	if (!is_vmlinux(modname) ||
1584 	     (is_vmlinux(modname) && vmlinux_section_warnings))
1585 		check_sec_ref(mod, modname, &info);
1586 
1587 	version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1588 	if (version)
1589 		maybe_frob_rcs_version(modname, version, info.modinfo,
1590 				       version - (char *)info.hdr);
1591 	if (version || (all_versions && !is_vmlinux(modname)))
1592 		get_src_version(modname, mod->srcversion,
1593 				sizeof(mod->srcversion)-1);
1594 
1595 	get_markers(&info, mod);
1596 
1597 	parse_elf_finish(&info);
1598 
1599 	/* Our trick to get versioning for module struct etc. - it's
1600 	 * never passed as an argument to an exported function, so
1601 	 * the automatic versioning doesn't pick it up, but it's really
1602 	 * important anyhow */
1603 	if (modversions)
1604 		mod->unres = alloc_symbol("module_layout", 0, mod->unres);
1605 }
1606 
1607 #define SZ 500
1608 
1609 /* We first write the generated file into memory using the
1610  * following helper, then compare to the file on disk and
1611  * only update the later if anything changed */
1612 
1613 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
1614 						      const char *fmt, ...)
1615 {
1616 	char tmp[SZ];
1617 	int len;
1618 	va_list ap;
1619 
1620 	va_start(ap, fmt);
1621 	len = vsnprintf(tmp, SZ, fmt, ap);
1622 	buf_write(buf, tmp, len);
1623 	va_end(ap);
1624 }
1625 
1626 void buf_write(struct buffer *buf, const char *s, int len)
1627 {
1628 	if (buf->size - buf->pos < len) {
1629 		buf->size += len + SZ;
1630 		buf->p = realloc(buf->p, buf->size);
1631 	}
1632 	strncpy(buf->p + buf->pos, s, len);
1633 	buf->pos += len;
1634 }
1635 
1636 static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
1637 {
1638 	const char *e = is_vmlinux(m) ?"":".ko";
1639 
1640 	switch (exp) {
1641 	case export_gpl:
1642 		fatal("modpost: GPL-incompatible module %s%s "
1643 		      "uses GPL-only symbol '%s'\n", m, e, s);
1644 		break;
1645 	case export_unused_gpl:
1646 		fatal("modpost: GPL-incompatible module %s%s "
1647 		      "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
1648 		break;
1649 	case export_gpl_future:
1650 		warn("modpost: GPL-incompatible module %s%s "
1651 		      "uses future GPL-only symbol '%s'\n", m, e, s);
1652 		break;
1653 	case export_plain:
1654 	case export_unused:
1655 	case export_unknown:
1656 		/* ignore */
1657 		break;
1658 	}
1659 }
1660 
1661 static void check_for_unused(enum export exp, const char *m, const char *s)
1662 {
1663 	const char *e = is_vmlinux(m) ?"":".ko";
1664 
1665 	switch (exp) {
1666 	case export_unused:
1667 	case export_unused_gpl:
1668 		warn("modpost: module %s%s "
1669 		      "uses symbol '%s' marked UNUSED\n", m, e, s);
1670 		break;
1671 	default:
1672 		/* ignore */
1673 		break;
1674 	}
1675 }
1676 
1677 static void check_exports(struct module *mod)
1678 {
1679 	struct symbol *s, *exp;
1680 
1681 	for (s = mod->unres; s; s = s->next) {
1682 		const char *basename;
1683 		exp = find_symbol(s->name);
1684 		if (!exp || exp->module == mod)
1685 			continue;
1686 		basename = strrchr(mod->name, '/');
1687 		if (basename)
1688 			basename++;
1689 		else
1690 			basename = mod->name;
1691 		if (!mod->gpl_compatible)
1692 			check_for_gpl_usage(exp->export, basename, exp->name);
1693 		check_for_unused(exp->export, basename, exp->name);
1694 	}
1695 }
1696 
1697 /**
1698  * Header for the generated file
1699  **/
1700 static void add_header(struct buffer *b, struct module *mod)
1701 {
1702 	buf_printf(b, "#include <linux/module.h>\n");
1703 	buf_printf(b, "#include <linux/vermagic.h>\n");
1704 	buf_printf(b, "#include <linux/compiler.h>\n");
1705 	buf_printf(b, "\n");
1706 	buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
1707 	buf_printf(b, "\n");
1708 	buf_printf(b, "struct module __this_module\n");
1709 	buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
1710 	buf_printf(b, " .name = KBUILD_MODNAME,\n");
1711 	if (mod->has_init)
1712 		buf_printf(b, " .init = init_module,\n");
1713 	if (mod->has_cleanup)
1714 		buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
1715 			      " .exit = cleanup_module,\n"
1716 			      "#endif\n");
1717 	buf_printf(b, " .arch = MODULE_ARCH_INIT,\n");
1718 	buf_printf(b, "};\n");
1719 }
1720 
1721 void add_staging_flag(struct buffer *b, const char *name)
1722 {
1723 	static const char *staging_dir = "drivers/staging";
1724 
1725 	if (strncmp(staging_dir, name, strlen(staging_dir)) == 0)
1726 		buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
1727 }
1728 
1729 /**
1730  * Record CRCs for unresolved symbols
1731  **/
1732 static int add_versions(struct buffer *b, struct module *mod)
1733 {
1734 	struct symbol *s, *exp;
1735 	int err = 0;
1736 
1737 	for (s = mod->unres; s; s = s->next) {
1738 		exp = find_symbol(s->name);
1739 		if (!exp || exp->module == mod) {
1740 			if (have_vmlinux && !s->weak) {
1741 				if (warn_unresolved) {
1742 					warn("\"%s\" [%s.ko] undefined!\n",
1743 					     s->name, mod->name);
1744 				} else {
1745 					merror("\"%s\" [%s.ko] undefined!\n",
1746 					          s->name, mod->name);
1747 					err = 1;
1748 				}
1749 			}
1750 			continue;
1751 		}
1752 		s->module = exp->module;
1753 		s->crc_valid = exp->crc_valid;
1754 		s->crc = exp->crc;
1755 	}
1756 
1757 	if (!modversions)
1758 		return err;
1759 
1760 	buf_printf(b, "\n");
1761 	buf_printf(b, "static const struct modversion_info ____versions[]\n");
1762 	buf_printf(b, "__used\n");
1763 	buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
1764 
1765 	for (s = mod->unres; s; s = s->next) {
1766 		if (!s->module)
1767 			continue;
1768 		if (!s->crc_valid) {
1769 			warn("\"%s\" [%s.ko] has no CRC!\n",
1770 				s->name, mod->name);
1771 			continue;
1772 		}
1773 		buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name);
1774 	}
1775 
1776 	buf_printf(b, "};\n");
1777 
1778 	return err;
1779 }
1780 
1781 static void add_depends(struct buffer *b, struct module *mod,
1782 			struct module *modules)
1783 {
1784 	struct symbol *s;
1785 	struct module *m;
1786 	int first = 1;
1787 
1788 	for (m = modules; m; m = m->next)
1789 		m->seen = is_vmlinux(m->name);
1790 
1791 	buf_printf(b, "\n");
1792 	buf_printf(b, "static const char __module_depends[]\n");
1793 	buf_printf(b, "__used\n");
1794 	buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
1795 	buf_printf(b, "\"depends=");
1796 	for (s = mod->unres; s; s = s->next) {
1797 		const char *p;
1798 		if (!s->module)
1799 			continue;
1800 
1801 		if (s->module->seen)
1802 			continue;
1803 
1804 		s->module->seen = 1;
1805 		p = strrchr(s->module->name, '/');
1806 		if (p)
1807 			p++;
1808 		else
1809 			p = s->module->name;
1810 		buf_printf(b, "%s%s", first ? "" : ",", p);
1811 		first = 0;
1812 	}
1813 	buf_printf(b, "\";\n");
1814 }
1815 
1816 static void add_srcversion(struct buffer *b, struct module *mod)
1817 {
1818 	if (mod->srcversion[0]) {
1819 		buf_printf(b, "\n");
1820 		buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
1821 			   mod->srcversion);
1822 	}
1823 }
1824 
1825 static void write_if_changed(struct buffer *b, const char *fname)
1826 {
1827 	char *tmp;
1828 	FILE *file;
1829 	struct stat st;
1830 
1831 	file = fopen(fname, "r");
1832 	if (!file)
1833 		goto write;
1834 
1835 	if (fstat(fileno(file), &st) < 0)
1836 		goto close_write;
1837 
1838 	if (st.st_size != b->pos)
1839 		goto close_write;
1840 
1841 	tmp = NOFAIL(malloc(b->pos));
1842 	if (fread(tmp, 1, b->pos, file) != b->pos)
1843 		goto free_write;
1844 
1845 	if (memcmp(tmp, b->p, b->pos) != 0)
1846 		goto free_write;
1847 
1848 	free(tmp);
1849 	fclose(file);
1850 	return;
1851 
1852  free_write:
1853 	free(tmp);
1854  close_write:
1855 	fclose(file);
1856  write:
1857 	file = fopen(fname, "w");
1858 	if (!file) {
1859 		perror(fname);
1860 		exit(1);
1861 	}
1862 	if (fwrite(b->p, 1, b->pos, file) != b->pos) {
1863 		perror(fname);
1864 		exit(1);
1865 	}
1866 	fclose(file);
1867 }
1868 
1869 /* parse Module.symvers file. line format:
1870  * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
1871  **/
1872 static void read_dump(const char *fname, unsigned int kernel)
1873 {
1874 	unsigned long size, pos = 0;
1875 	void *file = grab_file(fname, &size);
1876 	char *line;
1877 
1878 	if (!file)
1879 		/* No symbol versions, silently ignore */
1880 		return;
1881 
1882 	while ((line = get_next_line(&pos, file, size))) {
1883 		char *symname, *modname, *d, *export, *end;
1884 		unsigned int crc;
1885 		struct module *mod;
1886 		struct symbol *s;
1887 
1888 		if (!(symname = strchr(line, '\t')))
1889 			goto fail;
1890 		*symname++ = '\0';
1891 		if (!(modname = strchr(symname, '\t')))
1892 			goto fail;
1893 		*modname++ = '\0';
1894 		if ((export = strchr(modname, '\t')) != NULL)
1895 			*export++ = '\0';
1896 		if (export && ((end = strchr(export, '\t')) != NULL))
1897 			*end = '\0';
1898 		crc = strtoul(line, &d, 16);
1899 		if (*symname == '\0' || *modname == '\0' || *d != '\0')
1900 			goto fail;
1901 		mod = find_module(modname);
1902 		if (!mod) {
1903 			if (is_vmlinux(modname))
1904 				have_vmlinux = 1;
1905 			mod = new_module(modname);
1906 			mod->skip = 1;
1907 		}
1908 		s = sym_add_exported(symname, mod, export_no(export));
1909 		s->kernel    = kernel;
1910 		s->preloaded = 1;
1911 		sym_update_crc(symname, mod, crc, export_no(export));
1912 	}
1913 	return;
1914 fail:
1915 	fatal("parse error in symbol dump file\n");
1916 }
1917 
1918 /* For normal builds always dump all symbols.
1919  * For external modules only dump symbols
1920  * that are not read from kernel Module.symvers.
1921  **/
1922 static int dump_sym(struct symbol *sym)
1923 {
1924 	if (!external_module)
1925 		return 1;
1926 	if (sym->vmlinux || sym->kernel)
1927 		return 0;
1928 	return 1;
1929 }
1930 
1931 static void write_dump(const char *fname)
1932 {
1933 	struct buffer buf = { };
1934 	struct symbol *symbol;
1935 	int n;
1936 
1937 	for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
1938 		symbol = symbolhash[n];
1939 		while (symbol) {
1940 			if (dump_sym(symbol))
1941 				buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
1942 					symbol->crc, symbol->name,
1943 					symbol->module->name,
1944 					export_str(symbol->export));
1945 			symbol = symbol->next;
1946 		}
1947 	}
1948 	write_if_changed(&buf, fname);
1949 }
1950 
1951 static void add_marker(struct module *mod, const char *name, const char *fmt)
1952 {
1953 	char *line = NULL;
1954 	asprintf(&line, "%s\t%s\t%s\n", name, mod->name, fmt);
1955 	NOFAIL(line);
1956 
1957 	mod->markers = NOFAIL(realloc(mod->markers, ((mod->nmarkers + 1) *
1958 						     sizeof mod->markers[0])));
1959 	mod->markers[mod->nmarkers++] = line;
1960 }
1961 
1962 static void read_markers(const char *fname)
1963 {
1964 	unsigned long size, pos = 0;
1965 	void *file = grab_file(fname, &size);
1966 	char *line;
1967 
1968 	if (!file)		/* No old markers, silently ignore */
1969 		return;
1970 
1971 	while ((line = get_next_line(&pos, file, size))) {
1972 		char *marker, *modname, *fmt;
1973 		struct module *mod;
1974 
1975 		marker = line;
1976 		modname = strchr(marker, '\t');
1977 		if (!modname)
1978 			goto fail;
1979 		*modname++ = '\0';
1980 		fmt = strchr(modname, '\t');
1981 		if (!fmt)
1982 			goto fail;
1983 		*fmt++ = '\0';
1984 		if (*marker == '\0' || *modname == '\0')
1985 			goto fail;
1986 
1987 		mod = find_module(modname);
1988 		if (!mod) {
1989 			mod = new_module(modname);
1990 			mod->skip = 1;
1991 		}
1992 		if (is_vmlinux(modname)) {
1993 			have_vmlinux = 1;
1994 			mod->skip = 0;
1995 		}
1996 
1997 		if (!mod->skip)
1998 			add_marker(mod, marker, fmt);
1999 	}
2000 	release_file(file, size);
2001 	return;
2002 fail:
2003 	fatal("parse error in markers list file\n");
2004 }
2005 
2006 static int compare_strings(const void *a, const void *b)
2007 {
2008 	return strcmp(*(const char **) a, *(const char **) b);
2009 }
2010 
2011 static void write_markers(const char *fname)
2012 {
2013 	struct buffer buf = { };
2014 	struct module *mod;
2015 	size_t i;
2016 
2017 	for (mod = modules; mod; mod = mod->next)
2018 		if ((!external_module || !mod->skip) && mod->markers != NULL) {
2019 			/*
2020 			 * Sort the strings so we can skip duplicates when
2021 			 * we write them out.
2022 			 */
2023 			qsort(mod->markers, mod->nmarkers,
2024 			      sizeof mod->markers[0], &compare_strings);
2025 			for (i = 0; i < mod->nmarkers; ++i) {
2026 				char *line = mod->markers[i];
2027 				buf_write(&buf, line, strlen(line));
2028 				while (i + 1 < mod->nmarkers &&
2029 				       !strcmp(mod->markers[i],
2030 					       mod->markers[i + 1]))
2031 					free(mod->markers[i++]);
2032 				free(mod->markers[i]);
2033 			}
2034 			free(mod->markers);
2035 			mod->markers = NULL;
2036 		}
2037 
2038 	write_if_changed(&buf, fname);
2039 }
2040 
2041 struct ext_sym_list {
2042 	struct ext_sym_list *next;
2043 	const char *file;
2044 };
2045 
2046 int main(int argc, char **argv)
2047 {
2048 	struct module *mod;
2049 	struct buffer buf = { };
2050 	char *kernel_read = NULL, *module_read = NULL;
2051 	char *dump_write = NULL;
2052 	char *markers_read = NULL;
2053 	char *markers_write = NULL;
2054 	int opt;
2055 	int err;
2056 	struct ext_sym_list *extsym_iter;
2057 	struct ext_sym_list *extsym_start = NULL;
2058 
2059 	while ((opt = getopt(argc, argv, "i:I:e:cmsSo:awM:K:")) != -1) {
2060 		switch (opt) {
2061 		case 'i':
2062 			kernel_read = optarg;
2063 			break;
2064 		case 'I':
2065 			module_read = optarg;
2066 			external_module = 1;
2067 			break;
2068 		case 'c':
2069 			cross_build = 1;
2070 			break;
2071 		case 'e':
2072 			external_module = 1;
2073 			extsym_iter =
2074 			   NOFAIL(malloc(sizeof(*extsym_iter)));
2075 			extsym_iter->next = extsym_start;
2076 			extsym_iter->file = optarg;
2077 			extsym_start = extsym_iter;
2078 			break;
2079 		case 'm':
2080 			modversions = 1;
2081 			break;
2082 		case 'o':
2083 			dump_write = optarg;
2084 			break;
2085 		case 'a':
2086 			all_versions = 1;
2087 			break;
2088 		case 's':
2089 			vmlinux_section_warnings = 0;
2090 			break;
2091 		case 'S':
2092 			sec_mismatch_verbose = 0;
2093 			break;
2094 		case 'w':
2095 			warn_unresolved = 1;
2096 			break;
2097 			case 'M':
2098 				markers_write = optarg;
2099 				break;
2100 			case 'K':
2101 				markers_read = optarg;
2102 				break;
2103 		default:
2104 			exit(1);
2105 		}
2106 	}
2107 
2108 	if (kernel_read)
2109 		read_dump(kernel_read, 1);
2110 	if (module_read)
2111 		read_dump(module_read, 0);
2112 	while (extsym_start) {
2113 		read_dump(extsym_start->file, 0);
2114 		extsym_iter = extsym_start->next;
2115 		free(extsym_start);
2116 		extsym_start = extsym_iter;
2117 	}
2118 
2119 	while (optind < argc)
2120 		read_symbols(argv[optind++]);
2121 
2122 	for (mod = modules; mod; mod = mod->next) {
2123 		if (mod->skip)
2124 			continue;
2125 		check_exports(mod);
2126 	}
2127 
2128 	err = 0;
2129 
2130 	for (mod = modules; mod; mod = mod->next) {
2131 		char fname[strlen(mod->name) + 10];
2132 
2133 		if (mod->skip)
2134 			continue;
2135 
2136 		buf.pos = 0;
2137 
2138 		add_header(&buf, mod);
2139 		add_staging_flag(&buf, mod->name);
2140 		err |= add_versions(&buf, mod);
2141 		add_depends(&buf, mod, modules);
2142 		add_moddevtable(&buf, mod);
2143 		add_srcversion(&buf, mod);
2144 
2145 		sprintf(fname, "%s.mod.c", mod->name);
2146 		write_if_changed(&buf, fname);
2147 	}
2148 
2149 	if (dump_write)
2150 		write_dump(dump_write);
2151 	if (sec_mismatch_count && !sec_mismatch_verbose)
2152 		warn("modpost: Found %d section mismatch(es).\n"
2153 		     "To see full details build your kernel with:\n"
2154 		     "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n",
2155 		     sec_mismatch_count);
2156 
2157 	if (markers_read)
2158 		read_markers(markers_read);
2159 
2160 	if (markers_write)
2161 		write_markers(markers_write);
2162 
2163 	return err;
2164 }
2165