xref: /openbmc/linux/scripts/mod/modpost.c (revision c819e2cf)
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 /* ignore missing files */
42 static int ignore_missing_files;
43 
44 enum export {
45 	export_plain,      export_unused,     export_gpl,
46 	export_unused_gpl, export_gpl_future, export_unknown
47 };
48 
49 #define PRINTF __attribute__ ((format (printf, 1, 2)))
50 
51 PRINTF void fatal(const char *fmt, ...)
52 {
53 	va_list arglist;
54 
55 	fprintf(stderr, "FATAL: ");
56 
57 	va_start(arglist, fmt);
58 	vfprintf(stderr, fmt, arglist);
59 	va_end(arglist);
60 
61 	exit(1);
62 }
63 
64 PRINTF void warn(const char *fmt, ...)
65 {
66 	va_list arglist;
67 
68 	fprintf(stderr, "WARNING: ");
69 
70 	va_start(arglist, fmt);
71 	vfprintf(stderr, fmt, arglist);
72 	va_end(arglist);
73 }
74 
75 PRINTF void merror(const char *fmt, ...)
76 {
77 	va_list arglist;
78 
79 	fprintf(stderr, "ERROR: ");
80 
81 	va_start(arglist, fmt);
82 	vfprintf(stderr, fmt, arglist);
83 	va_end(arglist);
84 }
85 
86 static inline bool strends(const char *str, const char *postfix)
87 {
88 	if (strlen(str) < strlen(postfix))
89 		return false;
90 
91 	return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0;
92 }
93 
94 static int is_vmlinux(const char *modname)
95 {
96 	const char *myname;
97 
98 	myname = strrchr(modname, '/');
99 	if (myname)
100 		myname++;
101 	else
102 		myname = modname;
103 
104 	return (strcmp(myname, "vmlinux") == 0) ||
105 	       (strcmp(myname, "vmlinux.o") == 0);
106 }
107 
108 void *do_nofail(void *ptr, const char *expr)
109 {
110 	if (!ptr)
111 		fatal("modpost: Memory allocation failure: %s.\n", expr);
112 
113 	return ptr;
114 }
115 
116 /* A list of all modules we processed */
117 static struct module *modules;
118 
119 static struct module *find_module(char *modname)
120 {
121 	struct module *mod;
122 
123 	for (mod = modules; mod; mod = mod->next)
124 		if (strcmp(mod->name, modname) == 0)
125 			break;
126 	return mod;
127 }
128 
129 static struct module *new_module(const char *modname)
130 {
131 	struct module *mod;
132 	char *p;
133 
134 	mod = NOFAIL(malloc(sizeof(*mod)));
135 	memset(mod, 0, sizeof(*mod));
136 	p = NOFAIL(strdup(modname));
137 
138 	/* strip trailing .o */
139 	if (strends(p, ".o")) {
140 		p[strlen(p) - 2] = '\0';
141 		mod->is_dot_o = 1;
142 	}
143 
144 	/* add to list */
145 	mod->name = p;
146 	mod->gpl_compatible = -1;
147 	mod->next = modules;
148 	modules = mod;
149 
150 	return mod;
151 }
152 
153 /* A hash of all exported symbols,
154  * struct symbol is also used for lists of unresolved symbols */
155 
156 #define SYMBOL_HASH_SIZE 1024
157 
158 struct symbol {
159 	struct symbol *next;
160 	struct module *module;
161 	unsigned int crc;
162 	int crc_valid;
163 	unsigned int weak:1;
164 	unsigned int vmlinux:1;    /* 1 if symbol is defined in vmlinux */
165 	unsigned int kernel:1;     /* 1 if symbol is from kernel
166 				    *  (only for external modules) **/
167 	unsigned int preloaded:1;  /* 1 if symbol from Module.symvers, or crc */
168 	enum export  export;       /* Type of export */
169 	char name[0];
170 };
171 
172 static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
173 
174 /* This is based on the hash agorithm from gdbm, via tdb */
175 static inline unsigned int tdb_hash(const char *name)
176 {
177 	unsigned value;	/* Used to compute the hash value.  */
178 	unsigned   i;	/* Used to cycle through random values. */
179 
180 	/* Set the initial value from the key size. */
181 	for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
182 		value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
183 
184 	return (1103515243 * value + 12345);
185 }
186 
187 /**
188  * Allocate a new symbols for use in the hash of exported symbols or
189  * the list of unresolved symbols per module
190  **/
191 static struct symbol *alloc_symbol(const char *name, unsigned int weak,
192 				   struct symbol *next)
193 {
194 	struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
195 
196 	memset(s, 0, sizeof(*s));
197 	strcpy(s->name, name);
198 	s->weak = weak;
199 	s->next = next;
200 	return s;
201 }
202 
203 /* For the hash of exported symbols */
204 static struct symbol *new_symbol(const char *name, struct module *module,
205 				 enum export export)
206 {
207 	unsigned int hash;
208 	struct symbol *new;
209 
210 	hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
211 	new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
212 	new->module = module;
213 	new->export = export;
214 	return new;
215 }
216 
217 static struct symbol *find_symbol(const char *name)
218 {
219 	struct symbol *s;
220 
221 	/* For our purposes, .foo matches foo.  PPC64 needs this. */
222 	if (name[0] == '.')
223 		name++;
224 
225 	for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
226 		if (strcmp(s->name, name) == 0)
227 			return s;
228 	}
229 	return NULL;
230 }
231 
232 static const struct {
233 	const char *str;
234 	enum export export;
235 } export_list[] = {
236 	{ .str = "EXPORT_SYMBOL",            .export = export_plain },
237 	{ .str = "EXPORT_UNUSED_SYMBOL",     .export = export_unused },
238 	{ .str = "EXPORT_SYMBOL_GPL",        .export = export_gpl },
239 	{ .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
240 	{ .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
241 	{ .str = "(unknown)",                .export = export_unknown },
242 };
243 
244 
245 static const char *export_str(enum export ex)
246 {
247 	return export_list[ex].str;
248 }
249 
250 static enum export export_no(const char *s)
251 {
252 	int i;
253 
254 	if (!s)
255 		return export_unknown;
256 	for (i = 0; export_list[i].export != export_unknown; i++) {
257 		if (strcmp(export_list[i].str, s) == 0)
258 			return export_list[i].export;
259 	}
260 	return export_unknown;
261 }
262 
263 static const char *sec_name(struct elf_info *elf, int secindex);
264 
265 #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)
266 
267 static enum export export_from_secname(struct elf_info *elf, unsigned int sec)
268 {
269 	const char *secname = sec_name(elf, sec);
270 
271 	if (strstarts(secname, "___ksymtab+"))
272 		return export_plain;
273 	else if (strstarts(secname, "___ksymtab_unused+"))
274 		return export_unused;
275 	else if (strstarts(secname, "___ksymtab_gpl+"))
276 		return export_gpl;
277 	else if (strstarts(secname, "___ksymtab_unused_gpl+"))
278 		return export_unused_gpl;
279 	else if (strstarts(secname, "___ksymtab_gpl_future+"))
280 		return export_gpl_future;
281 	else
282 		return export_unknown;
283 }
284 
285 static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
286 {
287 	if (sec == elf->export_sec)
288 		return export_plain;
289 	else if (sec == elf->export_unused_sec)
290 		return export_unused;
291 	else if (sec == elf->export_gpl_sec)
292 		return export_gpl;
293 	else if (sec == elf->export_unused_gpl_sec)
294 		return export_unused_gpl;
295 	else if (sec == elf->export_gpl_future_sec)
296 		return export_gpl_future;
297 	else
298 		return export_unknown;
299 }
300 
301 /**
302  * Add an exported symbol - it may have already been added without a
303  * CRC, in this case just update the CRC
304  **/
305 static struct symbol *sym_add_exported(const char *name, struct module *mod,
306 				       enum export export)
307 {
308 	struct symbol *s = find_symbol(name);
309 
310 	if (!s) {
311 		s = new_symbol(name, mod, export);
312 	} else {
313 		if (!s->preloaded) {
314 			warn("%s: '%s' exported twice. Previous export "
315 			     "was in %s%s\n", mod->name, name,
316 			     s->module->name,
317 			     is_vmlinux(s->module->name) ?"":".ko");
318 		} else {
319 			/* In case Module.symvers was out of date */
320 			s->module = mod;
321 		}
322 	}
323 	s->preloaded = 0;
324 	s->vmlinux   = is_vmlinux(mod->name);
325 	s->kernel    = 0;
326 	s->export    = export;
327 	return s;
328 }
329 
330 static void sym_update_crc(const char *name, struct module *mod,
331 			   unsigned int crc, enum export export)
332 {
333 	struct symbol *s = find_symbol(name);
334 
335 	if (!s) {
336 		s = new_symbol(name, mod, export);
337 		/* Don't complain when we find it later. */
338 		s->preloaded = 1;
339 	}
340 	s->crc = crc;
341 	s->crc_valid = 1;
342 }
343 
344 void *grab_file(const char *filename, unsigned long *size)
345 {
346 	struct stat st;
347 	void *map = MAP_FAILED;
348 	int fd;
349 
350 	fd = open(filename, O_RDONLY);
351 	if (fd < 0)
352 		return NULL;
353 	if (fstat(fd, &st))
354 		goto failed;
355 
356 	*size = st.st_size;
357 	map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
358 
359 failed:
360 	close(fd);
361 	if (map == MAP_FAILED)
362 		return NULL;
363 	return map;
364 }
365 
366 /**
367   * Return a copy of the next line in a mmap'ed file.
368   * spaces in the beginning of the line is trimmed away.
369   * Return a pointer to a static buffer.
370   **/
371 char *get_next_line(unsigned long *pos, void *file, unsigned long size)
372 {
373 	static char line[4096];
374 	int skip = 1;
375 	size_t len = 0;
376 	signed char *p = (signed char *)file + *pos;
377 	char *s = line;
378 
379 	for (; *pos < size ; (*pos)++) {
380 		if (skip && isspace(*p)) {
381 			p++;
382 			continue;
383 		}
384 		skip = 0;
385 		if (*p != '\n' && (*pos < size)) {
386 			len++;
387 			*s++ = *p++;
388 			if (len > 4095)
389 				break; /* Too long, stop */
390 		} else {
391 			/* End of string */
392 			*s = '\0';
393 			return line;
394 		}
395 	}
396 	/* End of buffer */
397 	return NULL;
398 }
399 
400 void release_file(void *file, unsigned long size)
401 {
402 	munmap(file, size);
403 }
404 
405 static int parse_elf(struct elf_info *info, const char *filename)
406 {
407 	unsigned int i;
408 	Elf_Ehdr *hdr;
409 	Elf_Shdr *sechdrs;
410 	Elf_Sym  *sym;
411 	const char *secstrings;
412 	unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
413 
414 	hdr = grab_file(filename, &info->size);
415 	if (!hdr) {
416 		if (ignore_missing_files) {
417 			fprintf(stderr, "%s: %s (ignored)\n", filename,
418 				strerror(errno));
419 			return 0;
420 		}
421 		perror(filename);
422 		exit(1);
423 	}
424 	info->hdr = hdr;
425 	if (info->size < sizeof(*hdr)) {
426 		/* file too small, assume this is an empty .o file */
427 		return 0;
428 	}
429 	/* Is this a valid ELF file? */
430 	if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
431 	    (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
432 	    (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
433 	    (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
434 		/* Not an ELF file - silently ignore it */
435 		return 0;
436 	}
437 	/* Fix endianness in ELF header */
438 	hdr->e_type      = TO_NATIVE(hdr->e_type);
439 	hdr->e_machine   = TO_NATIVE(hdr->e_machine);
440 	hdr->e_version   = TO_NATIVE(hdr->e_version);
441 	hdr->e_entry     = TO_NATIVE(hdr->e_entry);
442 	hdr->e_phoff     = TO_NATIVE(hdr->e_phoff);
443 	hdr->e_shoff     = TO_NATIVE(hdr->e_shoff);
444 	hdr->e_flags     = TO_NATIVE(hdr->e_flags);
445 	hdr->e_ehsize    = TO_NATIVE(hdr->e_ehsize);
446 	hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
447 	hdr->e_phnum     = TO_NATIVE(hdr->e_phnum);
448 	hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
449 	hdr->e_shnum     = TO_NATIVE(hdr->e_shnum);
450 	hdr->e_shstrndx  = TO_NATIVE(hdr->e_shstrndx);
451 	sechdrs = (void *)hdr + hdr->e_shoff;
452 	info->sechdrs = sechdrs;
453 
454 	/* Check if file offset is correct */
455 	if (hdr->e_shoff > info->size) {
456 		fatal("section header offset=%lu in file '%s' is bigger than "
457 		      "filesize=%lu\n", (unsigned long)hdr->e_shoff,
458 		      filename, info->size);
459 		return 0;
460 	}
461 
462 	if (hdr->e_shnum == SHN_UNDEF) {
463 		/*
464 		 * There are more than 64k sections,
465 		 * read count from .sh_size.
466 		 */
467 		info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
468 	}
469 	else {
470 		info->num_sections = hdr->e_shnum;
471 	}
472 	if (hdr->e_shstrndx == SHN_XINDEX) {
473 		info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
474 	}
475 	else {
476 		info->secindex_strings = hdr->e_shstrndx;
477 	}
478 
479 	/* Fix endianness in section headers */
480 	for (i = 0; i < info->num_sections; i++) {
481 		sechdrs[i].sh_name      = TO_NATIVE(sechdrs[i].sh_name);
482 		sechdrs[i].sh_type      = TO_NATIVE(sechdrs[i].sh_type);
483 		sechdrs[i].sh_flags     = TO_NATIVE(sechdrs[i].sh_flags);
484 		sechdrs[i].sh_addr      = TO_NATIVE(sechdrs[i].sh_addr);
485 		sechdrs[i].sh_offset    = TO_NATIVE(sechdrs[i].sh_offset);
486 		sechdrs[i].sh_size      = TO_NATIVE(sechdrs[i].sh_size);
487 		sechdrs[i].sh_link      = TO_NATIVE(sechdrs[i].sh_link);
488 		sechdrs[i].sh_info      = TO_NATIVE(sechdrs[i].sh_info);
489 		sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
490 		sechdrs[i].sh_entsize   = TO_NATIVE(sechdrs[i].sh_entsize);
491 	}
492 	/* Find symbol table. */
493 	secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
494 	for (i = 1; i < info->num_sections; i++) {
495 		const char *secname;
496 		int nobits = sechdrs[i].sh_type == SHT_NOBITS;
497 
498 		if (!nobits && sechdrs[i].sh_offset > info->size) {
499 			fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
500 			      "sizeof(*hrd)=%zu\n", filename,
501 			      (unsigned long)sechdrs[i].sh_offset,
502 			      sizeof(*hdr));
503 			return 0;
504 		}
505 		secname = secstrings + sechdrs[i].sh_name;
506 		if (strcmp(secname, ".modinfo") == 0) {
507 			if (nobits)
508 				fatal("%s has NOBITS .modinfo\n", filename);
509 			info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
510 			info->modinfo_len = sechdrs[i].sh_size;
511 		} else if (strcmp(secname, "__ksymtab") == 0)
512 			info->export_sec = i;
513 		else if (strcmp(secname, "__ksymtab_unused") == 0)
514 			info->export_unused_sec = i;
515 		else if (strcmp(secname, "__ksymtab_gpl") == 0)
516 			info->export_gpl_sec = i;
517 		else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
518 			info->export_unused_gpl_sec = i;
519 		else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
520 			info->export_gpl_future_sec = i;
521 
522 		if (sechdrs[i].sh_type == SHT_SYMTAB) {
523 			unsigned int sh_link_idx;
524 			symtab_idx = i;
525 			info->symtab_start = (void *)hdr +
526 			    sechdrs[i].sh_offset;
527 			info->symtab_stop  = (void *)hdr +
528 			    sechdrs[i].sh_offset + sechdrs[i].sh_size;
529 			sh_link_idx = sechdrs[i].sh_link;
530 			info->strtab       = (void *)hdr +
531 			    sechdrs[sh_link_idx].sh_offset;
532 		}
533 
534 		/* 32bit section no. table? ("more than 64k sections") */
535 		if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
536 			symtab_shndx_idx = i;
537 			info->symtab_shndx_start = (void *)hdr +
538 			    sechdrs[i].sh_offset;
539 			info->symtab_shndx_stop  = (void *)hdr +
540 			    sechdrs[i].sh_offset + sechdrs[i].sh_size;
541 		}
542 	}
543 	if (!info->symtab_start)
544 		fatal("%s has no symtab?\n", filename);
545 
546 	/* Fix endianness in symbols */
547 	for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
548 		sym->st_shndx = TO_NATIVE(sym->st_shndx);
549 		sym->st_name  = TO_NATIVE(sym->st_name);
550 		sym->st_value = TO_NATIVE(sym->st_value);
551 		sym->st_size  = TO_NATIVE(sym->st_size);
552 	}
553 
554 	if (symtab_shndx_idx != ~0U) {
555 		Elf32_Word *p;
556 		if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
557 			fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
558 			      filename, sechdrs[symtab_shndx_idx].sh_link,
559 			      symtab_idx);
560 		/* Fix endianness */
561 		for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
562 		     p++)
563 			*p = TO_NATIVE(*p);
564 	}
565 
566 	return 1;
567 }
568 
569 static void parse_elf_finish(struct elf_info *info)
570 {
571 	release_file(info->hdr, info->size);
572 }
573 
574 static int ignore_undef_symbol(struct elf_info *info, const char *symname)
575 {
576 	/* ignore __this_module, it will be resolved shortly */
577 	if (strcmp(symname, VMLINUX_SYMBOL_STR(__this_module)) == 0)
578 		return 1;
579 	/* ignore global offset table */
580 	if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
581 		return 1;
582 	if (info->hdr->e_machine == EM_PPC)
583 		/* Special register function linked on all modules during final link of .ko */
584 		if (strncmp(symname, "_restgpr_", sizeof("_restgpr_") - 1) == 0 ||
585 		    strncmp(symname, "_savegpr_", sizeof("_savegpr_") - 1) == 0 ||
586 		    strncmp(symname, "_rest32gpr_", sizeof("_rest32gpr_") - 1) == 0 ||
587 		    strncmp(symname, "_save32gpr_", sizeof("_save32gpr_") - 1) == 0 ||
588 		    strncmp(symname, "_restvr_", sizeof("_restvr_") - 1) == 0 ||
589 		    strncmp(symname, "_savevr_", sizeof("_savevr_") - 1) == 0)
590 			return 1;
591 	if (info->hdr->e_machine == EM_PPC64)
592 		/* Special register function linked on all modules during final link of .ko */
593 		if (strncmp(symname, "_restgpr0_", sizeof("_restgpr0_") - 1) == 0 ||
594 		    strncmp(symname, "_savegpr0_", sizeof("_savegpr0_") - 1) == 0 ||
595 		    strncmp(symname, "_restvr_", sizeof("_restvr_") - 1) == 0 ||
596 		    strncmp(symname, "_savevr_", sizeof("_savevr_") - 1) == 0)
597 			return 1;
598 	/* Do not ignore this symbol */
599 	return 0;
600 }
601 
602 #define CRC_PFX     VMLINUX_SYMBOL_STR(__crc_)
603 #define KSYMTAB_PFX VMLINUX_SYMBOL_STR(__ksymtab_)
604 
605 static void handle_modversions(struct module *mod, struct elf_info *info,
606 			       Elf_Sym *sym, const char *symname)
607 {
608 	unsigned int crc;
609 	enum export export;
610 
611 	if ((!is_vmlinux(mod->name) || mod->is_dot_o) &&
612 	    strncmp(symname, "__ksymtab", 9) == 0)
613 		export = export_from_secname(info, get_secindex(info, sym));
614 	else
615 		export = export_from_sec(info, get_secindex(info, sym));
616 
617 	/* CRC'd symbol */
618 	if (strncmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
619 		crc = (unsigned int) sym->st_value;
620 		sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
621 				export);
622 	}
623 
624 	switch (sym->st_shndx) {
625 	case SHN_COMMON:
626 		if (!strncmp(symname, "__gnu_lto_", sizeof("__gnu_lto_")-1)) {
627 			/* Should warn here, but modpost runs before the linker */
628 		} else
629 			warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
630 		break;
631 	case SHN_UNDEF:
632 		/* undefined symbol */
633 		if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
634 		    ELF_ST_BIND(sym->st_info) != STB_WEAK)
635 			break;
636 		if (ignore_undef_symbol(info, symname))
637 			break;
638 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
639 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
640 /* add compatibility with older glibc */
641 #ifndef STT_SPARC_REGISTER
642 #define STT_SPARC_REGISTER STT_REGISTER
643 #endif
644 		if (info->hdr->e_machine == EM_SPARC ||
645 		    info->hdr->e_machine == EM_SPARCV9) {
646 			/* Ignore register directives. */
647 			if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
648 				break;
649 			if (symname[0] == '.') {
650 				char *munged = strdup(symname);
651 				munged[0] = '_';
652 				munged[1] = toupper(munged[1]);
653 				symname = munged;
654 			}
655 		}
656 #endif
657 
658 #ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX
659 		if (symname[0] != '_')
660 			break;
661 		else
662 			symname++;
663 #endif
664 		mod->unres = alloc_symbol(symname,
665 					  ELF_ST_BIND(sym->st_info) == STB_WEAK,
666 					  mod->unres);
667 		break;
668 	default:
669 		/* All exported symbols */
670 		if (strncmp(symname, KSYMTAB_PFX, strlen(KSYMTAB_PFX)) == 0) {
671 			sym_add_exported(symname + strlen(KSYMTAB_PFX), mod,
672 					export);
673 		}
674 		if (strcmp(symname, VMLINUX_SYMBOL_STR(init_module)) == 0)
675 			mod->has_init = 1;
676 		if (strcmp(symname, VMLINUX_SYMBOL_STR(cleanup_module)) == 0)
677 			mod->has_cleanup = 1;
678 		break;
679 	}
680 }
681 
682 /**
683  * Parse tag=value strings from .modinfo section
684  **/
685 static char *next_string(char *string, unsigned long *secsize)
686 {
687 	/* Skip non-zero chars */
688 	while (string[0]) {
689 		string++;
690 		if ((*secsize)-- <= 1)
691 			return NULL;
692 	}
693 
694 	/* Skip any zero padding. */
695 	while (!string[0]) {
696 		string++;
697 		if ((*secsize)-- <= 1)
698 			return NULL;
699 	}
700 	return string;
701 }
702 
703 static char *get_next_modinfo(void *modinfo, unsigned long modinfo_len,
704 			      const char *tag, char *info)
705 {
706 	char *p;
707 	unsigned int taglen = strlen(tag);
708 	unsigned long size = modinfo_len;
709 
710 	if (info) {
711 		size -= info - (char *)modinfo;
712 		modinfo = next_string(info, &size);
713 	}
714 
715 	for (p = modinfo; p; p = next_string(p, &size)) {
716 		if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
717 			return p + taglen + 1;
718 	}
719 	return NULL;
720 }
721 
722 static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
723 			 const char *tag)
724 
725 {
726 	return get_next_modinfo(modinfo, modinfo_len, tag, NULL);
727 }
728 
729 /**
730  * Test if string s ends in string sub
731  * return 0 if match
732  **/
733 static int strrcmp(const char *s, const char *sub)
734 {
735 	int slen, sublen;
736 
737 	if (!s || !sub)
738 		return 1;
739 
740 	slen = strlen(s);
741 	sublen = strlen(sub);
742 
743 	if ((slen == 0) || (sublen == 0))
744 		return 1;
745 
746 	if (sublen > slen)
747 		return 1;
748 
749 	return memcmp(s + slen - sublen, sub, sublen);
750 }
751 
752 static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
753 {
754 	if (sym)
755 		return elf->strtab + sym->st_name;
756 	else
757 		return "(unknown)";
758 }
759 
760 static const char *sec_name(struct elf_info *elf, int secindex)
761 {
762 	Elf_Shdr *sechdrs = elf->sechdrs;
763 	return (void *)elf->hdr +
764 		elf->sechdrs[elf->secindex_strings].sh_offset +
765 		sechdrs[secindex].sh_name;
766 }
767 
768 static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr)
769 {
770 	return (void *)elf->hdr +
771 		elf->sechdrs[elf->secindex_strings].sh_offset +
772 		sechdr->sh_name;
773 }
774 
775 /* The pattern is an array of simple patterns.
776  * "foo" will match an exact string equal to "foo"
777  * "*foo" will match a string that ends with "foo"
778  * "foo*" will match a string that begins with "foo"
779  */
780 static int match(const char *sym, const char * const pat[])
781 {
782 	const char *p;
783 	while (*pat) {
784 		p = *pat++;
785 		const char *endp = p + strlen(p) - 1;
786 
787 		/* "*foo" */
788 		if (*p == '*') {
789 			if (strrcmp(sym, p + 1) == 0)
790 				return 1;
791 		}
792 		/* "foo*" */
793 		else if (*endp == '*') {
794 			if (strncmp(sym, p, strlen(p) - 1) == 0)
795 				return 1;
796 		}
797 		/* no wildcards */
798 		else {
799 			if (strcmp(p, sym) == 0)
800 				return 1;
801 		}
802 	}
803 	/* no match */
804 	return 0;
805 }
806 
807 /* sections that we do not want to do full section mismatch check on */
808 static const char *const section_white_list[] =
809 {
810 	".comment*",
811 	".debug*",
812 	".cranges",		/* sh64 */
813 	".zdebug*",		/* Compressed debug sections. */
814 	".GCC-command-line",	/* mn10300 */
815 	".GCC.command.line",	/* record-gcc-switches, non mn10300 */
816 	".mdebug*",        /* alpha, score, mips etc. */
817 	".pdr",            /* alpha, score, mips etc. */
818 	".stab*",
819 	".note*",
820 	".got*",
821 	".toc*",
822 	".xt.prop",				 /* xtensa */
823 	".xt.lit",         /* xtensa */
824 	".arcextmap*",			/* arc */
825 	".gnu.linkonce.arcext*",	/* arc : modules */
826 	".gnu.lto*",
827 	NULL
828 };
829 
830 /*
831  * This is used to find sections missing the SHF_ALLOC flag.
832  * The cause of this is often a section specified in assembler
833  * without "ax" / "aw".
834  */
835 static void check_section(const char *modname, struct elf_info *elf,
836 			  Elf_Shdr *sechdr)
837 {
838 	const char *sec = sech_name(elf, sechdr);
839 
840 	if (sechdr->sh_type == SHT_PROGBITS &&
841 	    !(sechdr->sh_flags & SHF_ALLOC) &&
842 	    !match(sec, section_white_list)) {
843 		warn("%s (%s): unexpected non-allocatable section.\n"
844 		     "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
845 		     "Note that for example <linux/init.h> contains\n"
846 		     "section definitions for use in .S files.\n\n",
847 		     modname, sec);
848 	}
849 }
850 
851 
852 
853 #define ALL_INIT_DATA_SECTIONS \
854 	".init.setup", ".init.rodata", ".meminit.rodata", \
855 	".init.data", ".meminit.data"
856 #define ALL_EXIT_DATA_SECTIONS \
857 	".exit.data", ".memexit.data"
858 
859 #define ALL_INIT_TEXT_SECTIONS \
860 	".init.text", ".meminit.text"
861 #define ALL_EXIT_TEXT_SECTIONS \
862 	".exit.text", ".memexit.text"
863 
864 #define ALL_PCI_INIT_SECTIONS	\
865 	".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
866 	".pci_fixup_enable", ".pci_fixup_resume", \
867 	".pci_fixup_resume_early", ".pci_fixup_suspend"
868 
869 #define ALL_XXXINIT_SECTIONS MEM_INIT_SECTIONS
870 #define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS
871 
872 #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
873 #define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
874 
875 #define DATA_SECTIONS ".data", ".data.rel"
876 #define TEXT_SECTIONS ".text", ".text.unlikely"
877 
878 #define INIT_SECTIONS      ".init.*"
879 #define MEM_INIT_SECTIONS  ".meminit.*"
880 
881 #define EXIT_SECTIONS      ".exit.*"
882 #define MEM_EXIT_SECTIONS  ".memexit.*"
883 
884 /* init data sections */
885 static const char *const init_data_sections[] =
886 	{ ALL_INIT_DATA_SECTIONS, NULL };
887 
888 /* all init sections */
889 static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL };
890 
891 /* All init and exit sections (code + data) */
892 static const char *const init_exit_sections[] =
893 	{ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
894 
895 /* data section */
896 static const char *const data_sections[] = { DATA_SECTIONS, NULL };
897 
898 
899 /* symbols in .data that may refer to init/exit sections */
900 #define DEFAULT_SYMBOL_WHITE_LIST					\
901 	"*driver",							\
902 	"*_template", /* scsi uses *_template a lot */			\
903 	"*_timer",    /* arm uses ops structures named _timer a lot */	\
904 	"*_sht",      /* scsi also used *_sht to some extent */		\
905 	"*_ops",							\
906 	"*_probe",							\
907 	"*_probe_one",							\
908 	"*_console"
909 
910 static const char *const head_sections[] = { ".head.text*", NULL };
911 static const char *const linker_symbols[] =
912 	{ "__init_begin", "_sinittext", "_einittext", NULL };
913 
914 enum mismatch {
915 	TEXT_TO_ANY_INIT,
916 	DATA_TO_ANY_INIT,
917 	TEXT_TO_ANY_EXIT,
918 	DATA_TO_ANY_EXIT,
919 	XXXINIT_TO_SOME_INIT,
920 	XXXEXIT_TO_SOME_EXIT,
921 	ANY_INIT_TO_ANY_EXIT,
922 	ANY_EXIT_TO_ANY_INIT,
923 	EXPORT_TO_INIT_EXIT,
924 };
925 
926 struct sectioncheck {
927 	const char *fromsec[20];
928 	const char *tosec[20];
929 	enum mismatch mismatch;
930 	const char *symbol_white_list[20];
931 };
932 
933 static const struct sectioncheck sectioncheck[] = {
934 /* Do not reference init/exit code/data from
935  * normal code and data
936  */
937 {
938 	.fromsec = { TEXT_SECTIONS, NULL },
939 	.tosec   = { ALL_INIT_SECTIONS, NULL },
940 	.mismatch = TEXT_TO_ANY_INIT,
941 	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
942 },
943 {
944 	.fromsec = { DATA_SECTIONS, NULL },
945 	.tosec   = { ALL_XXXINIT_SECTIONS, NULL },
946 	.mismatch = DATA_TO_ANY_INIT,
947 	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
948 },
949 {
950 	.fromsec = { DATA_SECTIONS, NULL },
951 	.tosec   = { INIT_SECTIONS, NULL },
952 	.mismatch = DATA_TO_ANY_INIT,
953 	.symbol_white_list = {
954 		"*_template", "*_timer", "*_sht", "*_ops",
955 		"*_probe", "*_probe_one", "*_console", NULL
956 	},
957 },
958 {
959 	.fromsec = { TEXT_SECTIONS, NULL },
960 	.tosec   = { ALL_EXIT_SECTIONS, NULL },
961 	.mismatch = TEXT_TO_ANY_EXIT,
962 	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
963 },
964 {
965 	.fromsec = { DATA_SECTIONS, NULL },
966 	.tosec   = { ALL_EXIT_SECTIONS, NULL },
967 	.mismatch = DATA_TO_ANY_EXIT,
968 	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
969 },
970 /* Do not reference init code/data from meminit code/data */
971 {
972 	.fromsec = { ALL_XXXINIT_SECTIONS, NULL },
973 	.tosec   = { INIT_SECTIONS, NULL },
974 	.mismatch = XXXINIT_TO_SOME_INIT,
975 	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
976 },
977 /* Do not reference exit code/data from memexit code/data */
978 {
979 	.fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
980 	.tosec   = { EXIT_SECTIONS, NULL },
981 	.mismatch = XXXEXIT_TO_SOME_EXIT,
982 	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
983 },
984 /* Do not use exit code/data from init code */
985 {
986 	.fromsec = { ALL_INIT_SECTIONS, NULL },
987 	.tosec   = { ALL_EXIT_SECTIONS, NULL },
988 	.mismatch = ANY_INIT_TO_ANY_EXIT,
989 	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
990 },
991 /* Do not use init code/data from exit code */
992 {
993 	.fromsec = { ALL_EXIT_SECTIONS, NULL },
994 	.tosec   = { ALL_INIT_SECTIONS, NULL },
995 	.mismatch = ANY_EXIT_TO_ANY_INIT,
996 	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
997 },
998 {
999 	.fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
1000 	.tosec   = { INIT_SECTIONS, NULL },
1001 	.mismatch = ANY_INIT_TO_ANY_EXIT,
1002 	.symbol_white_list = { NULL },
1003 },
1004 /* Do not export init/exit functions or data */
1005 {
1006 	.fromsec = { "__ksymtab*", NULL },
1007 	.tosec   = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
1008 	.mismatch = EXPORT_TO_INIT_EXIT,
1009 	.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1010 }
1011 };
1012 
1013 static const struct sectioncheck *section_mismatch(
1014 		const char *fromsec, const char *tosec)
1015 {
1016 	int i;
1017 	int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
1018 	const struct sectioncheck *check = &sectioncheck[0];
1019 
1020 	for (i = 0; i < elems; i++) {
1021 		if (match(fromsec, check->fromsec) &&
1022 		    match(tosec, check->tosec))
1023 			return check;
1024 		check++;
1025 	}
1026 	return NULL;
1027 }
1028 
1029 /**
1030  * Whitelist to allow certain references to pass with no warning.
1031  *
1032  * Pattern 1:
1033  *   If a module parameter is declared __initdata and permissions=0
1034  *   then this is legal despite the warning generated.
1035  *   We cannot see value of permissions here, so just ignore
1036  *   this pattern.
1037  *   The pattern is identified by:
1038  *   tosec   = .init.data
1039  *   fromsec = .data*
1040  *   atsym   =__param*
1041  *
1042  * Pattern 1a:
1043  *   module_param_call() ops can refer to __init set function if permissions=0
1044  *   The pattern is identified by:
1045  *   tosec   = .init.text
1046  *   fromsec = .data*
1047  *   atsym   = __param_ops_*
1048  *
1049  * Pattern 2:
1050  *   Many drivers utilise a *driver container with references to
1051  *   add, remove, probe functions etc.
1052  *   the pattern is identified by:
1053  *   tosec   = init or exit section
1054  *   fromsec = data section
1055  *   atsym = *driver, *_template, *_sht, *_ops, *_probe,
1056  *           *probe_one, *_console, *_timer
1057  *
1058  * Pattern 3:
1059  *   Whitelist all references from .head.text to any init section
1060  *
1061  * Pattern 4:
1062  *   Some symbols belong to init section but still it is ok to reference
1063  *   these from non-init sections as these symbols don't have any memory
1064  *   allocated for them and symbol address and value are same. So even
1065  *   if init section is freed, its ok to reference those symbols.
1066  *   For ex. symbols marking the init section boundaries.
1067  *   This pattern is identified by
1068  *   refsymname = __init_begin, _sinittext, _einittext
1069  *
1070  **/
1071 static int secref_whitelist(const struct sectioncheck *mismatch,
1072 			    const char *fromsec, const char *fromsym,
1073 			    const char *tosec, const char *tosym)
1074 {
1075 	/* Check for pattern 1 */
1076 	if (match(tosec, init_data_sections) &&
1077 	    match(fromsec, data_sections) &&
1078 	    (strncmp(fromsym, "__param", strlen("__param")) == 0))
1079 		return 0;
1080 
1081 	/* Check for pattern 1a */
1082 	if (strcmp(tosec, ".init.text") == 0 &&
1083 	    match(fromsec, data_sections) &&
1084 	    (strncmp(fromsym, "__param_ops_", strlen("__param_ops_")) == 0))
1085 		return 0;
1086 
1087 	/* Check for pattern 2 */
1088 	if (match(tosec, init_exit_sections) &&
1089 	    match(fromsec, data_sections) &&
1090 	    match(fromsym, mismatch->symbol_white_list))
1091 		return 0;
1092 
1093 	/* Check for pattern 3 */
1094 	if (match(fromsec, head_sections) &&
1095 	    match(tosec, init_sections))
1096 		return 0;
1097 
1098 	/* Check for pattern 4 */
1099 	if (match(tosym, linker_symbols))
1100 		return 0;
1101 
1102 	return 1;
1103 }
1104 
1105 /**
1106  * Find symbol based on relocation record info.
1107  * In some cases the symbol supplied is a valid symbol so
1108  * return refsym. If st_name != 0 we assume this is a valid symbol.
1109  * In other cases the symbol needs to be looked up in the symbol table
1110  * based on section and address.
1111  *  **/
1112 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
1113 				Elf_Sym *relsym)
1114 {
1115 	Elf_Sym *sym;
1116 	Elf_Sym *near = NULL;
1117 	Elf64_Sword distance = 20;
1118 	Elf64_Sword d;
1119 	unsigned int relsym_secindex;
1120 
1121 	if (relsym->st_name != 0)
1122 		return relsym;
1123 
1124 	relsym_secindex = get_secindex(elf, relsym);
1125 	for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1126 		if (get_secindex(elf, sym) != relsym_secindex)
1127 			continue;
1128 		if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
1129 			continue;
1130 		if (sym->st_value == addr)
1131 			return sym;
1132 		/* Find a symbol nearby - addr are maybe negative */
1133 		d = sym->st_value - addr;
1134 		if (d < 0)
1135 			d = addr - sym->st_value;
1136 		if (d < distance) {
1137 			distance = d;
1138 			near = sym;
1139 		}
1140 	}
1141 	/* We need a close match */
1142 	if (distance < 20)
1143 		return near;
1144 	else
1145 		return NULL;
1146 }
1147 
1148 static inline int is_arm_mapping_symbol(const char *str)
1149 {
1150 	return str[0] == '$' && strchr("axtd", str[1])
1151 	       && (str[2] == '\0' || str[2] == '.');
1152 }
1153 
1154 /*
1155  * If there's no name there, ignore it; likewise, ignore it if it's
1156  * one of the magic symbols emitted used by current ARM tools.
1157  *
1158  * Otherwise if find_symbols_between() returns those symbols, they'll
1159  * fail the whitelist tests and cause lots of false alarms ... fixable
1160  * only by merging __exit and __init sections into __text, bloating
1161  * the kernel (which is especially evil on embedded platforms).
1162  */
1163 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1164 {
1165 	const char *name = elf->strtab + sym->st_name;
1166 
1167 	if (!name || !strlen(name))
1168 		return 0;
1169 	return !is_arm_mapping_symbol(name);
1170 }
1171 
1172 /*
1173  * Find symbols before or equal addr and after addr - in the section sec.
1174  * If we find two symbols with equal offset prefer one with a valid name.
1175  * The ELF format may have a better way to detect what type of symbol
1176  * it is, but this works for now.
1177  **/
1178 static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1179 				 const char *sec)
1180 {
1181 	Elf_Sym *sym;
1182 	Elf_Sym *near = NULL;
1183 	Elf_Addr distance = ~0;
1184 
1185 	for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1186 		const char *symsec;
1187 
1188 		if (is_shndx_special(sym->st_shndx))
1189 			continue;
1190 		symsec = sec_name(elf, get_secindex(elf, sym));
1191 		if (strcmp(symsec, sec) != 0)
1192 			continue;
1193 		if (!is_valid_name(elf, sym))
1194 			continue;
1195 		if (sym->st_value <= addr) {
1196 			if ((addr - sym->st_value) < distance) {
1197 				distance = addr - sym->st_value;
1198 				near = sym;
1199 			} else if ((addr - sym->st_value) == distance) {
1200 				near = sym;
1201 			}
1202 		}
1203 	}
1204 	return near;
1205 }
1206 
1207 /*
1208  * Convert a section name to the function/data attribute
1209  * .init.text => __init
1210  * .memexitconst => __memconst
1211  * etc.
1212  *
1213  * The memory of returned value has been allocated on a heap. The user of this
1214  * method should free it after usage.
1215 */
1216 static char *sec2annotation(const char *s)
1217 {
1218 	if (match(s, init_exit_sections)) {
1219 		char *p = malloc(20);
1220 		char *r = p;
1221 
1222 		*p++ = '_';
1223 		*p++ = '_';
1224 		if (*s == '.')
1225 			s++;
1226 		while (*s && *s != '.')
1227 			*p++ = *s++;
1228 		*p = '\0';
1229 		if (*s == '.')
1230 			s++;
1231 		if (strstr(s, "rodata") != NULL)
1232 			strcat(p, "const ");
1233 		else if (strstr(s, "data") != NULL)
1234 			strcat(p, "data ");
1235 		else
1236 			strcat(p, " ");
1237 		return r;
1238 	} else {
1239 		return strdup("");
1240 	}
1241 }
1242 
1243 static int is_function(Elf_Sym *sym)
1244 {
1245 	if (sym)
1246 		return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1247 	else
1248 		return -1;
1249 }
1250 
1251 static void print_section_list(const char * const list[20])
1252 {
1253 	const char *const *s = list;
1254 
1255 	while (*s) {
1256 		fprintf(stderr, "%s", *s);
1257 		s++;
1258 		if (*s)
1259 			fprintf(stderr, ", ");
1260 	}
1261 	fprintf(stderr, "\n");
1262 }
1263 
1264 /*
1265  * Print a warning about a section mismatch.
1266  * Try to find symbols near it so user can find it.
1267  * Check whitelist before warning - it may be a false positive.
1268  */
1269 static void report_sec_mismatch(const char *modname,
1270 				const struct sectioncheck *mismatch,
1271 				const char *fromsec,
1272 				unsigned long long fromaddr,
1273 				const char *fromsym,
1274 				int from_is_func,
1275 				const char *tosec, const char *tosym,
1276 				int to_is_func)
1277 {
1278 	const char *from, *from_p;
1279 	const char *to, *to_p;
1280 	char *prl_from;
1281 	char *prl_to;
1282 
1283 	switch (from_is_func) {
1284 	case 0: from = "variable"; from_p = "";   break;
1285 	case 1: from = "function"; from_p = "()"; break;
1286 	default: from = "(unknown reference)"; from_p = ""; break;
1287 	}
1288 	switch (to_is_func) {
1289 	case 0: to = "variable"; to_p = "";   break;
1290 	case 1: to = "function"; to_p = "()"; break;
1291 	default: to = "(unknown reference)"; to_p = ""; break;
1292 	}
1293 
1294 	sec_mismatch_count++;
1295 	if (!sec_mismatch_verbose)
1296 		return;
1297 
1298 	warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1299 	     "to the %s %s:%s%s\n",
1300 	     modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1301 	     tosym, to_p);
1302 
1303 	switch (mismatch->mismatch) {
1304 	case TEXT_TO_ANY_INIT:
1305 		prl_from = sec2annotation(fromsec);
1306 		prl_to = sec2annotation(tosec);
1307 		fprintf(stderr,
1308 		"The function %s%s() references\n"
1309 		"the %s %s%s%s.\n"
1310 		"This is often because %s lacks a %s\n"
1311 		"annotation or the annotation of %s is wrong.\n",
1312 		prl_from, fromsym,
1313 		to, prl_to, tosym, to_p,
1314 		fromsym, prl_to, tosym);
1315 		free(prl_from);
1316 		free(prl_to);
1317 		break;
1318 	case DATA_TO_ANY_INIT: {
1319 		prl_to = sec2annotation(tosec);
1320 		fprintf(stderr,
1321 		"The variable %s references\n"
1322 		"the %s %s%s%s\n"
1323 		"If the reference is valid then annotate the\n"
1324 		"variable with __init* or __refdata (see linux/init.h) "
1325 		"or name the variable:\n",
1326 		fromsym, to, prl_to, tosym, to_p);
1327 		print_section_list(mismatch->symbol_white_list);
1328 		free(prl_to);
1329 		break;
1330 	}
1331 	case TEXT_TO_ANY_EXIT:
1332 		prl_to = sec2annotation(tosec);
1333 		fprintf(stderr,
1334 		"The function %s() references a %s in an exit section.\n"
1335 		"Often the %s %s%s has valid usage outside the exit section\n"
1336 		"and the fix is to remove the %sannotation of %s.\n",
1337 		fromsym, to, to, tosym, to_p, prl_to, tosym);
1338 		free(prl_to);
1339 		break;
1340 	case DATA_TO_ANY_EXIT: {
1341 		prl_to = sec2annotation(tosec);
1342 		fprintf(stderr,
1343 		"The variable %s references\n"
1344 		"the %s %s%s%s\n"
1345 		"If the reference is valid then annotate the\n"
1346 		"variable with __exit* (see linux/init.h) or "
1347 		"name the variable:\n",
1348 		fromsym, to, prl_to, tosym, to_p);
1349 		print_section_list(mismatch->symbol_white_list);
1350 		free(prl_to);
1351 		break;
1352 	}
1353 	case XXXINIT_TO_SOME_INIT:
1354 	case XXXEXIT_TO_SOME_EXIT:
1355 		prl_from = sec2annotation(fromsec);
1356 		prl_to = sec2annotation(tosec);
1357 		fprintf(stderr,
1358 		"The %s %s%s%s references\n"
1359 		"a %s %s%s%s.\n"
1360 		"If %s is only used by %s then\n"
1361 		"annotate %s with a matching annotation.\n",
1362 		from, prl_from, fromsym, from_p,
1363 		to, prl_to, tosym, to_p,
1364 		tosym, fromsym, tosym);
1365 		free(prl_from);
1366 		free(prl_to);
1367 		break;
1368 	case ANY_INIT_TO_ANY_EXIT:
1369 		prl_from = sec2annotation(fromsec);
1370 		prl_to = sec2annotation(tosec);
1371 		fprintf(stderr,
1372 		"The %s %s%s%s references\n"
1373 		"a %s %s%s%s.\n"
1374 		"This is often seen when error handling "
1375 		"in the init function\n"
1376 		"uses functionality in the exit path.\n"
1377 		"The fix is often to remove the %sannotation of\n"
1378 		"%s%s so it may be used outside an exit section.\n",
1379 		from, prl_from, fromsym, from_p,
1380 		to, prl_to, tosym, to_p,
1381 		prl_to, tosym, to_p);
1382 		free(prl_from);
1383 		free(prl_to);
1384 		break;
1385 	case ANY_EXIT_TO_ANY_INIT:
1386 		prl_from = sec2annotation(fromsec);
1387 		prl_to = sec2annotation(tosec);
1388 		fprintf(stderr,
1389 		"The %s %s%s%s references\n"
1390 		"a %s %s%s%s.\n"
1391 		"This is often seen when error handling "
1392 		"in the exit function\n"
1393 		"uses functionality in the init path.\n"
1394 		"The fix is often to remove the %sannotation of\n"
1395 		"%s%s so it may be used outside an init section.\n",
1396 		from, prl_from, fromsym, from_p,
1397 		to, prl_to, tosym, to_p,
1398 		prl_to, tosym, to_p);
1399 		free(prl_from);
1400 		free(prl_to);
1401 		break;
1402 	case EXPORT_TO_INIT_EXIT:
1403 		prl_to = sec2annotation(tosec);
1404 		fprintf(stderr,
1405 		"The symbol %s is exported and annotated %s\n"
1406 		"Fix this by removing the %sannotation of %s "
1407 		"or drop the export.\n",
1408 		tosym, prl_to, prl_to, tosym);
1409 		free(prl_to);
1410 		break;
1411 	}
1412 	fprintf(stderr, "\n");
1413 }
1414 
1415 static void check_section_mismatch(const char *modname, struct elf_info *elf,
1416 				   Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1417 {
1418 	const char *tosec;
1419 	const struct sectioncheck *mismatch;
1420 
1421 	tosec = sec_name(elf, get_secindex(elf, sym));
1422 	mismatch = section_mismatch(fromsec, tosec);
1423 	if (mismatch) {
1424 		Elf_Sym *to;
1425 		Elf_Sym *from;
1426 		const char *tosym;
1427 		const char *fromsym;
1428 
1429 		from = find_elf_symbol2(elf, r->r_offset, fromsec);
1430 		fromsym = sym_name(elf, from);
1431 		to = find_elf_symbol(elf, r->r_addend, sym);
1432 		tosym = sym_name(elf, to);
1433 
1434 		if (!strncmp(fromsym, "reference___initcall",
1435 				sizeof("reference___initcall")-1))
1436 			return;
1437 
1438 		/* check whitelist - we may ignore it */
1439 		if (secref_whitelist(mismatch,
1440 					fromsec, fromsym, tosec, tosym)) {
1441 			report_sec_mismatch(modname, mismatch,
1442 			   fromsec, r->r_offset, fromsym,
1443 			   is_function(from), tosec, tosym,
1444 			   is_function(to));
1445 		}
1446 	}
1447 }
1448 
1449 static unsigned int *reloc_location(struct elf_info *elf,
1450 				    Elf_Shdr *sechdr, Elf_Rela *r)
1451 {
1452 	Elf_Shdr *sechdrs = elf->sechdrs;
1453 	int section = sechdr->sh_info;
1454 
1455 	return (void *)elf->hdr + sechdrs[section].sh_offset +
1456 		r->r_offset;
1457 }
1458 
1459 static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1460 {
1461 	unsigned int r_typ = ELF_R_TYPE(r->r_info);
1462 	unsigned int *location = reloc_location(elf, sechdr, r);
1463 
1464 	switch (r_typ) {
1465 	case R_386_32:
1466 		r->r_addend = TO_NATIVE(*location);
1467 		break;
1468 	case R_386_PC32:
1469 		r->r_addend = TO_NATIVE(*location) + 4;
1470 		/* For CONFIG_RELOCATABLE=y */
1471 		if (elf->hdr->e_type == ET_EXEC)
1472 			r->r_addend += r->r_offset;
1473 		break;
1474 	}
1475 	return 0;
1476 }
1477 
1478 #ifndef R_ARM_CALL
1479 #define R_ARM_CALL	28
1480 #endif
1481 #ifndef R_ARM_JUMP24
1482 #define R_ARM_JUMP24	29
1483 #endif
1484 
1485 #ifndef	R_ARM_THM_CALL
1486 #define	R_ARM_THM_CALL		10
1487 #endif
1488 #ifndef	R_ARM_THM_JUMP24
1489 #define	R_ARM_THM_JUMP24	30
1490 #endif
1491 #ifndef	R_ARM_THM_JUMP19
1492 #define	R_ARM_THM_JUMP19	51
1493 #endif
1494 
1495 static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1496 {
1497 	unsigned int r_typ = ELF_R_TYPE(r->r_info);
1498 
1499 	switch (r_typ) {
1500 	case R_ARM_ABS32:
1501 		/* From ARM ABI: (S + A) | T */
1502 		r->r_addend = (int)(long)
1503 			      (elf->symtab_start + ELF_R_SYM(r->r_info));
1504 		break;
1505 	case R_ARM_PC24:
1506 	case R_ARM_CALL:
1507 	case R_ARM_JUMP24:
1508 	case R_ARM_THM_CALL:
1509 	case R_ARM_THM_JUMP24:
1510 	case R_ARM_THM_JUMP19:
1511 		/* From ARM ABI: ((S + A) | T) - P */
1512 		r->r_addend = (int)(long)(elf->hdr +
1513 			      sechdr->sh_offset +
1514 			      (r->r_offset - sechdr->sh_addr));
1515 		break;
1516 	default:
1517 		return 1;
1518 	}
1519 	return 0;
1520 }
1521 
1522 static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1523 {
1524 	unsigned int r_typ = ELF_R_TYPE(r->r_info);
1525 	unsigned int *location = reloc_location(elf, sechdr, r);
1526 	unsigned int inst;
1527 
1528 	if (r_typ == R_MIPS_HI16)
1529 		return 1;	/* skip this */
1530 	inst = TO_NATIVE(*location);
1531 	switch (r_typ) {
1532 	case R_MIPS_LO16:
1533 		r->r_addend = inst & 0xffff;
1534 		break;
1535 	case R_MIPS_26:
1536 		r->r_addend = (inst & 0x03ffffff) << 2;
1537 		break;
1538 	case R_MIPS_32:
1539 		r->r_addend = inst;
1540 		break;
1541 	}
1542 	return 0;
1543 }
1544 
1545 static void section_rela(const char *modname, struct elf_info *elf,
1546 			 Elf_Shdr *sechdr)
1547 {
1548 	Elf_Sym  *sym;
1549 	Elf_Rela *rela;
1550 	Elf_Rela r;
1551 	unsigned int r_sym;
1552 	const char *fromsec;
1553 
1554 	Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1555 	Elf_Rela *stop  = (void *)start + sechdr->sh_size;
1556 
1557 	fromsec = sech_name(elf, sechdr);
1558 	fromsec += strlen(".rela");
1559 	/* if from section (name) is know good then skip it */
1560 	if (match(fromsec, section_white_list))
1561 		return;
1562 
1563 	for (rela = start; rela < stop; rela++) {
1564 		r.r_offset = TO_NATIVE(rela->r_offset);
1565 #if KERNEL_ELFCLASS == ELFCLASS64
1566 		if (elf->hdr->e_machine == EM_MIPS) {
1567 			unsigned int r_typ;
1568 			r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1569 			r_sym = TO_NATIVE(r_sym);
1570 			r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1571 			r.r_info = ELF64_R_INFO(r_sym, r_typ);
1572 		} else {
1573 			r.r_info = TO_NATIVE(rela->r_info);
1574 			r_sym = ELF_R_SYM(r.r_info);
1575 		}
1576 #else
1577 		r.r_info = TO_NATIVE(rela->r_info);
1578 		r_sym = ELF_R_SYM(r.r_info);
1579 #endif
1580 		r.r_addend = TO_NATIVE(rela->r_addend);
1581 		sym = elf->symtab_start + r_sym;
1582 		/* Skip special sections */
1583 		if (is_shndx_special(sym->st_shndx))
1584 			continue;
1585 		check_section_mismatch(modname, elf, &r, sym, fromsec);
1586 	}
1587 }
1588 
1589 static void section_rel(const char *modname, struct elf_info *elf,
1590 			Elf_Shdr *sechdr)
1591 {
1592 	Elf_Sym *sym;
1593 	Elf_Rel *rel;
1594 	Elf_Rela r;
1595 	unsigned int r_sym;
1596 	const char *fromsec;
1597 
1598 	Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1599 	Elf_Rel *stop  = (void *)start + sechdr->sh_size;
1600 
1601 	fromsec = sech_name(elf, sechdr);
1602 	fromsec += strlen(".rel");
1603 	/* if from section (name) is know good then skip it */
1604 	if (match(fromsec, section_white_list))
1605 		return;
1606 
1607 	for (rel = start; rel < stop; rel++) {
1608 		r.r_offset = TO_NATIVE(rel->r_offset);
1609 #if KERNEL_ELFCLASS == ELFCLASS64
1610 		if (elf->hdr->e_machine == EM_MIPS) {
1611 			unsigned int r_typ;
1612 			r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1613 			r_sym = TO_NATIVE(r_sym);
1614 			r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1615 			r.r_info = ELF64_R_INFO(r_sym, r_typ);
1616 		} else {
1617 			r.r_info = TO_NATIVE(rel->r_info);
1618 			r_sym = ELF_R_SYM(r.r_info);
1619 		}
1620 #else
1621 		r.r_info = TO_NATIVE(rel->r_info);
1622 		r_sym = ELF_R_SYM(r.r_info);
1623 #endif
1624 		r.r_addend = 0;
1625 		switch (elf->hdr->e_machine) {
1626 		case EM_386:
1627 			if (addend_386_rel(elf, sechdr, &r))
1628 				continue;
1629 			break;
1630 		case EM_ARM:
1631 			if (addend_arm_rel(elf, sechdr, &r))
1632 				continue;
1633 			break;
1634 		case EM_MIPS:
1635 			if (addend_mips_rel(elf, sechdr, &r))
1636 				continue;
1637 			break;
1638 		}
1639 		sym = elf->symtab_start + r_sym;
1640 		/* Skip special sections */
1641 		if (is_shndx_special(sym->st_shndx))
1642 			continue;
1643 		check_section_mismatch(modname, elf, &r, sym, fromsec);
1644 	}
1645 }
1646 
1647 /**
1648  * A module includes a number of sections that are discarded
1649  * either when loaded or when used as built-in.
1650  * For loaded modules all functions marked __init and all data
1651  * marked __initdata will be discarded when the module has been initialized.
1652  * Likewise for modules used built-in the sections marked __exit
1653  * are discarded because __exit marked function are supposed to be called
1654  * only when a module is unloaded which never happens for built-in modules.
1655  * The check_sec_ref() function traverses all relocation records
1656  * to find all references to a section that reference a section that will
1657  * be discarded and warns about it.
1658  **/
1659 static void check_sec_ref(struct module *mod, const char *modname,
1660 			  struct elf_info *elf)
1661 {
1662 	int i;
1663 	Elf_Shdr *sechdrs = elf->sechdrs;
1664 
1665 	/* Walk through all sections */
1666 	for (i = 0; i < elf->num_sections; i++) {
1667 		check_section(modname, elf, &elf->sechdrs[i]);
1668 		/* We want to process only relocation sections and not .init */
1669 		if (sechdrs[i].sh_type == SHT_RELA)
1670 			section_rela(modname, elf, &elf->sechdrs[i]);
1671 		else if (sechdrs[i].sh_type == SHT_REL)
1672 			section_rel(modname, elf, &elf->sechdrs[i]);
1673 	}
1674 }
1675 
1676 static char *remove_dot(char *s)
1677 {
1678 	size_t n = strcspn(s, ".");
1679 
1680 	if (n && s[n]) {
1681 		size_t m = strspn(s + n + 1, "0123456789");
1682 		if (m && (s[n + m] == '.' || s[n + m] == 0))
1683 			s[n] = 0;
1684 	}
1685 	return s;
1686 }
1687 
1688 static void read_symbols(char *modname)
1689 {
1690 	const char *symname;
1691 	char *version;
1692 	char *license;
1693 	struct module *mod;
1694 	struct elf_info info = { };
1695 	Elf_Sym *sym;
1696 
1697 	if (!parse_elf(&info, modname))
1698 		return;
1699 
1700 	mod = new_module(modname);
1701 
1702 	/* When there's no vmlinux, don't print warnings about
1703 	 * unresolved symbols (since there'll be too many ;) */
1704 	if (is_vmlinux(modname)) {
1705 		have_vmlinux = 1;
1706 		mod->skip = 1;
1707 	}
1708 
1709 	license = get_modinfo(info.modinfo, info.modinfo_len, "license");
1710 	if (info.modinfo && !license && !is_vmlinux(modname))
1711 		warn("modpost: missing MODULE_LICENSE() in %s\n"
1712 		     "see include/linux/module.h for "
1713 		     "more information\n", modname);
1714 	while (license) {
1715 		if (license_is_gpl_compatible(license))
1716 			mod->gpl_compatible = 1;
1717 		else {
1718 			mod->gpl_compatible = 0;
1719 			break;
1720 		}
1721 		license = get_next_modinfo(info.modinfo, info.modinfo_len,
1722 					   "license", license);
1723 	}
1724 
1725 	for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1726 		symname = remove_dot(info.strtab + sym->st_name);
1727 
1728 		handle_modversions(mod, &info, sym, symname);
1729 		handle_moddevtable(mod, &info, sym, symname);
1730 	}
1731 	if (!is_vmlinux(modname) ||
1732 	     (is_vmlinux(modname) && vmlinux_section_warnings))
1733 		check_sec_ref(mod, modname, &info);
1734 
1735 	version = get_modinfo(info.modinfo, info.modinfo_len, "version");
1736 	if (version)
1737 		maybe_frob_rcs_version(modname, version, info.modinfo,
1738 				       version - (char *)info.hdr);
1739 	if (version || (all_versions && !is_vmlinux(modname)))
1740 		get_src_version(modname, mod->srcversion,
1741 				sizeof(mod->srcversion)-1);
1742 
1743 	parse_elf_finish(&info);
1744 
1745 	/* Our trick to get versioning for module struct etc. - it's
1746 	 * never passed as an argument to an exported function, so
1747 	 * the automatic versioning doesn't pick it up, but it's really
1748 	 * important anyhow */
1749 	if (modversions)
1750 		mod->unres = alloc_symbol("module_layout", 0, mod->unres);
1751 }
1752 
1753 static void read_symbols_from_files(const char *filename)
1754 {
1755 	FILE *in = stdin;
1756 	char fname[PATH_MAX];
1757 
1758 	if (strcmp(filename, "-") != 0) {
1759 		in = fopen(filename, "r");
1760 		if (!in)
1761 			fatal("Can't open filenames file %s: %m", filename);
1762 	}
1763 
1764 	while (fgets(fname, PATH_MAX, in) != NULL) {
1765 		if (strends(fname, "\n"))
1766 			fname[strlen(fname)-1] = '\0';
1767 		read_symbols(fname);
1768 	}
1769 
1770 	if (in != stdin)
1771 		fclose(in);
1772 }
1773 
1774 #define SZ 500
1775 
1776 /* We first write the generated file into memory using the
1777  * following helper, then compare to the file on disk and
1778  * only update the later if anything changed */
1779 
1780 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
1781 						      const char *fmt, ...)
1782 {
1783 	char tmp[SZ];
1784 	int len;
1785 	va_list ap;
1786 
1787 	va_start(ap, fmt);
1788 	len = vsnprintf(tmp, SZ, fmt, ap);
1789 	buf_write(buf, tmp, len);
1790 	va_end(ap);
1791 }
1792 
1793 void buf_write(struct buffer *buf, const char *s, int len)
1794 {
1795 	if (buf->size - buf->pos < len) {
1796 		buf->size += len + SZ;
1797 		buf->p = realloc(buf->p, buf->size);
1798 	}
1799 	strncpy(buf->p + buf->pos, s, len);
1800 	buf->pos += len;
1801 }
1802 
1803 static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
1804 {
1805 	const char *e = is_vmlinux(m) ?"":".ko";
1806 
1807 	switch (exp) {
1808 	case export_gpl:
1809 		fatal("modpost: GPL-incompatible module %s%s "
1810 		      "uses GPL-only symbol '%s'\n", m, e, s);
1811 		break;
1812 	case export_unused_gpl:
1813 		fatal("modpost: GPL-incompatible module %s%s "
1814 		      "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
1815 		break;
1816 	case export_gpl_future:
1817 		warn("modpost: GPL-incompatible module %s%s "
1818 		      "uses future GPL-only symbol '%s'\n", m, e, s);
1819 		break;
1820 	case export_plain:
1821 	case export_unused:
1822 	case export_unknown:
1823 		/* ignore */
1824 		break;
1825 	}
1826 }
1827 
1828 static void check_for_unused(enum export exp, const char *m, const char *s)
1829 {
1830 	const char *e = is_vmlinux(m) ?"":".ko";
1831 
1832 	switch (exp) {
1833 	case export_unused:
1834 	case export_unused_gpl:
1835 		warn("modpost: module %s%s "
1836 		      "uses symbol '%s' marked UNUSED\n", m, e, s);
1837 		break;
1838 	default:
1839 		/* ignore */
1840 		break;
1841 	}
1842 }
1843 
1844 static void check_exports(struct module *mod)
1845 {
1846 	struct symbol *s, *exp;
1847 
1848 	for (s = mod->unres; s; s = s->next) {
1849 		const char *basename;
1850 		exp = find_symbol(s->name);
1851 		if (!exp || exp->module == mod)
1852 			continue;
1853 		basename = strrchr(mod->name, '/');
1854 		if (basename)
1855 			basename++;
1856 		else
1857 			basename = mod->name;
1858 		if (!mod->gpl_compatible)
1859 			check_for_gpl_usage(exp->export, basename, exp->name);
1860 		check_for_unused(exp->export, basename, exp->name);
1861 	}
1862 }
1863 
1864 /**
1865  * Header for the generated file
1866  **/
1867 static void add_header(struct buffer *b, struct module *mod)
1868 {
1869 	buf_printf(b, "#include <linux/module.h>\n");
1870 	buf_printf(b, "#include <linux/vermagic.h>\n");
1871 	buf_printf(b, "#include <linux/compiler.h>\n");
1872 	buf_printf(b, "\n");
1873 	buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
1874 	buf_printf(b, "\n");
1875 	buf_printf(b, "__visible struct module __this_module\n");
1876 	buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
1877 	buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
1878 	if (mod->has_init)
1879 		buf_printf(b, "\t.init = init_module,\n");
1880 	if (mod->has_cleanup)
1881 		buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
1882 			      "\t.exit = cleanup_module,\n"
1883 			      "#endif\n");
1884 	buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
1885 	buf_printf(b, "};\n");
1886 }
1887 
1888 static void add_intree_flag(struct buffer *b, int is_intree)
1889 {
1890 	if (is_intree)
1891 		buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
1892 }
1893 
1894 static void add_staging_flag(struct buffer *b, const char *name)
1895 {
1896 	static const char *staging_dir = "drivers/staging";
1897 
1898 	if (strncmp(staging_dir, name, strlen(staging_dir)) == 0)
1899 		buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
1900 }
1901 
1902 /**
1903  * Record CRCs for unresolved symbols
1904  **/
1905 static int add_versions(struct buffer *b, struct module *mod)
1906 {
1907 	struct symbol *s, *exp;
1908 	int err = 0;
1909 
1910 	for (s = mod->unres; s; s = s->next) {
1911 		exp = find_symbol(s->name);
1912 		if (!exp || exp->module == mod) {
1913 			if (have_vmlinux && !s->weak) {
1914 				if (warn_unresolved) {
1915 					warn("\"%s\" [%s.ko] undefined!\n",
1916 					     s->name, mod->name);
1917 				} else {
1918 					merror("\"%s\" [%s.ko] undefined!\n",
1919 					       s->name, mod->name);
1920 					err = 1;
1921 				}
1922 			}
1923 			continue;
1924 		}
1925 		s->module = exp->module;
1926 		s->crc_valid = exp->crc_valid;
1927 		s->crc = exp->crc;
1928 	}
1929 
1930 	if (!modversions)
1931 		return err;
1932 
1933 	buf_printf(b, "\n");
1934 	buf_printf(b, "static const struct modversion_info ____versions[]\n");
1935 	buf_printf(b, "__used\n");
1936 	buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
1937 
1938 	for (s = mod->unres; s; s = s->next) {
1939 		if (!s->module)
1940 			continue;
1941 		if (!s->crc_valid) {
1942 			warn("\"%s\" [%s.ko] has no CRC!\n",
1943 				s->name, mod->name);
1944 			continue;
1945 		}
1946 		buf_printf(b, "\t{ %#8x, __VMLINUX_SYMBOL_STR(%s) },\n",
1947 			   s->crc, s->name);
1948 	}
1949 
1950 	buf_printf(b, "};\n");
1951 
1952 	return err;
1953 }
1954 
1955 static void add_depends(struct buffer *b, struct module *mod,
1956 			struct module *modules)
1957 {
1958 	struct symbol *s;
1959 	struct module *m;
1960 	int first = 1;
1961 
1962 	for (m = modules; m; m = m->next)
1963 		m->seen = is_vmlinux(m->name);
1964 
1965 	buf_printf(b, "\n");
1966 	buf_printf(b, "static const char __module_depends[]\n");
1967 	buf_printf(b, "__used\n");
1968 	buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
1969 	buf_printf(b, "\"depends=");
1970 	for (s = mod->unres; s; s = s->next) {
1971 		const char *p;
1972 		if (!s->module)
1973 			continue;
1974 
1975 		if (s->module->seen)
1976 			continue;
1977 
1978 		s->module->seen = 1;
1979 		p = strrchr(s->module->name, '/');
1980 		if (p)
1981 			p++;
1982 		else
1983 			p = s->module->name;
1984 		buf_printf(b, "%s%s", first ? "" : ",", p);
1985 		first = 0;
1986 	}
1987 	buf_printf(b, "\";\n");
1988 }
1989 
1990 static void add_srcversion(struct buffer *b, struct module *mod)
1991 {
1992 	if (mod->srcversion[0]) {
1993 		buf_printf(b, "\n");
1994 		buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
1995 			   mod->srcversion);
1996 	}
1997 }
1998 
1999 static void write_if_changed(struct buffer *b, const char *fname)
2000 {
2001 	char *tmp;
2002 	FILE *file;
2003 	struct stat st;
2004 
2005 	file = fopen(fname, "r");
2006 	if (!file)
2007 		goto write;
2008 
2009 	if (fstat(fileno(file), &st) < 0)
2010 		goto close_write;
2011 
2012 	if (st.st_size != b->pos)
2013 		goto close_write;
2014 
2015 	tmp = NOFAIL(malloc(b->pos));
2016 	if (fread(tmp, 1, b->pos, file) != b->pos)
2017 		goto free_write;
2018 
2019 	if (memcmp(tmp, b->p, b->pos) != 0)
2020 		goto free_write;
2021 
2022 	free(tmp);
2023 	fclose(file);
2024 	return;
2025 
2026  free_write:
2027 	free(tmp);
2028  close_write:
2029 	fclose(file);
2030  write:
2031 	file = fopen(fname, "w");
2032 	if (!file) {
2033 		perror(fname);
2034 		exit(1);
2035 	}
2036 	if (fwrite(b->p, 1, b->pos, file) != b->pos) {
2037 		perror(fname);
2038 		exit(1);
2039 	}
2040 	fclose(file);
2041 }
2042 
2043 /* parse Module.symvers file. line format:
2044  * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
2045  **/
2046 static void read_dump(const char *fname, unsigned int kernel)
2047 {
2048 	unsigned long size, pos = 0;
2049 	void *file = grab_file(fname, &size);
2050 	char *line;
2051 
2052 	if (!file)
2053 		/* No symbol versions, silently ignore */
2054 		return;
2055 
2056 	while ((line = get_next_line(&pos, file, size))) {
2057 		char *symname, *modname, *d, *export, *end;
2058 		unsigned int crc;
2059 		struct module *mod;
2060 		struct symbol *s;
2061 
2062 		if (!(symname = strchr(line, '\t')))
2063 			goto fail;
2064 		*symname++ = '\0';
2065 		if (!(modname = strchr(symname, '\t')))
2066 			goto fail;
2067 		*modname++ = '\0';
2068 		if ((export = strchr(modname, '\t')) != NULL)
2069 			*export++ = '\0';
2070 		if (export && ((end = strchr(export, '\t')) != NULL))
2071 			*end = '\0';
2072 		crc = strtoul(line, &d, 16);
2073 		if (*symname == '\0' || *modname == '\0' || *d != '\0')
2074 			goto fail;
2075 		mod = find_module(modname);
2076 		if (!mod) {
2077 			if (is_vmlinux(modname))
2078 				have_vmlinux = 1;
2079 			mod = new_module(modname);
2080 			mod->skip = 1;
2081 		}
2082 		s = sym_add_exported(symname, mod, export_no(export));
2083 		s->kernel    = kernel;
2084 		s->preloaded = 1;
2085 		sym_update_crc(symname, mod, crc, export_no(export));
2086 	}
2087 	release_file(file, size);
2088 	return;
2089 fail:
2090 	release_file(file, size);
2091 	fatal("parse error in symbol dump file\n");
2092 }
2093 
2094 /* For normal builds always dump all symbols.
2095  * For external modules only dump symbols
2096  * that are not read from kernel Module.symvers.
2097  **/
2098 static int dump_sym(struct symbol *sym)
2099 {
2100 	if (!external_module)
2101 		return 1;
2102 	if (sym->vmlinux || sym->kernel)
2103 		return 0;
2104 	return 1;
2105 }
2106 
2107 static void write_dump(const char *fname)
2108 {
2109 	struct buffer buf = { };
2110 	struct symbol *symbol;
2111 	int n;
2112 
2113 	for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
2114 		symbol = symbolhash[n];
2115 		while (symbol) {
2116 			if (dump_sym(symbol))
2117 				buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
2118 					symbol->crc, symbol->name,
2119 					symbol->module->name,
2120 					export_str(symbol->export));
2121 			symbol = symbol->next;
2122 		}
2123 	}
2124 	write_if_changed(&buf, fname);
2125 }
2126 
2127 struct ext_sym_list {
2128 	struct ext_sym_list *next;
2129 	const char *file;
2130 };
2131 
2132 int main(int argc, char **argv)
2133 {
2134 	struct module *mod;
2135 	struct buffer buf = { };
2136 	char *kernel_read = NULL, *module_read = NULL;
2137 	char *dump_write = NULL, *files_source = NULL;
2138 	int opt;
2139 	int err;
2140 	struct ext_sym_list *extsym_iter;
2141 	struct ext_sym_list *extsym_start = NULL;
2142 
2143 	while ((opt = getopt(argc, argv, "i:I:e:mnsST:o:awM:K:")) != -1) {
2144 		switch (opt) {
2145 		case 'i':
2146 			kernel_read = optarg;
2147 			break;
2148 		case 'I':
2149 			module_read = optarg;
2150 			external_module = 1;
2151 			break;
2152 		case 'e':
2153 			external_module = 1;
2154 			extsym_iter =
2155 			   NOFAIL(malloc(sizeof(*extsym_iter)));
2156 			extsym_iter->next = extsym_start;
2157 			extsym_iter->file = optarg;
2158 			extsym_start = extsym_iter;
2159 			break;
2160 		case 'm':
2161 			modversions = 1;
2162 			break;
2163 		case 'n':
2164 			ignore_missing_files = 1;
2165 			break;
2166 		case 'o':
2167 			dump_write = optarg;
2168 			break;
2169 		case 'a':
2170 			all_versions = 1;
2171 			break;
2172 		case 's':
2173 			vmlinux_section_warnings = 0;
2174 			break;
2175 		case 'S':
2176 			sec_mismatch_verbose = 0;
2177 			break;
2178 		case 'T':
2179 			files_source = optarg;
2180 			break;
2181 		case 'w':
2182 			warn_unresolved = 1;
2183 			break;
2184 		default:
2185 			exit(1);
2186 		}
2187 	}
2188 
2189 	if (kernel_read)
2190 		read_dump(kernel_read, 1);
2191 	if (module_read)
2192 		read_dump(module_read, 0);
2193 	while (extsym_start) {
2194 		read_dump(extsym_start->file, 0);
2195 		extsym_iter = extsym_start->next;
2196 		free(extsym_start);
2197 		extsym_start = extsym_iter;
2198 	}
2199 
2200 	while (optind < argc)
2201 		read_symbols(argv[optind++]);
2202 
2203 	if (files_source)
2204 		read_symbols_from_files(files_source);
2205 
2206 	for (mod = modules; mod; mod = mod->next) {
2207 		if (mod->skip)
2208 			continue;
2209 		check_exports(mod);
2210 	}
2211 
2212 	err = 0;
2213 
2214 	for (mod = modules; mod; mod = mod->next) {
2215 		char fname[PATH_MAX];
2216 
2217 		if (mod->skip)
2218 			continue;
2219 
2220 		buf.pos = 0;
2221 
2222 		add_header(&buf, mod);
2223 		add_intree_flag(&buf, !external_module);
2224 		add_staging_flag(&buf, mod->name);
2225 		err |= add_versions(&buf, mod);
2226 		add_depends(&buf, mod, modules);
2227 		add_moddevtable(&buf, mod);
2228 		add_srcversion(&buf, mod);
2229 
2230 		sprintf(fname, "%s.mod.c", mod->name);
2231 		write_if_changed(&buf, fname);
2232 	}
2233 
2234 	if (dump_write)
2235 		write_dump(dump_write);
2236 	if (sec_mismatch_count && !sec_mismatch_verbose)
2237 		warn("modpost: Found %d section mismatch(es).\n"
2238 		     "To see full details build your kernel with:\n"
2239 		     "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n",
2240 		     sec_mismatch_count);
2241 
2242 	return err;
2243 }
2244