1 /* Postprocess module symbol versions
3 * Copyright 2003 Kai Germaschewski
4 * Copyright 2002-2004 Rusty Russell, IBM Corporation
5 * Copyright 2006 Sam Ravnborg
6 * Based in part on module-init-tools/depmod.c,file2alias
8 * This software may be used and distributed according to the terms
9 * of the GNU General Public License, incorporated herein by reference.
11 * Usage: modpost vmlinux module1.o module2.o ...
16 #include "../../include/linux/license.h"
18 /* Are we using CONFIG_MODVERSIONS? */
20 /* Warn about undefined symbols? (do so if we have vmlinux) */
22 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */
23 static int all_versions
= 0;
24 /* If we are modposting external module set to 1 */
25 static int external_module
= 0;
26 /* Only warn about unresolved symbols */
27 static int warn_unresolved
= 0;
28 /* How a symbol is exported */
30 export_plain
, export_unused
, export_gpl
,
31 export_unused_gpl
, export_gpl_future
, export_unknown
34 void fatal(const char *fmt
, ...)
38 fprintf(stderr
, "FATAL: ");
40 va_start(arglist
, fmt
);
41 vfprintf(stderr
, fmt
, arglist
);
47 void warn(const char *fmt
, ...)
51 fprintf(stderr
, "WARNING: ");
53 va_start(arglist
, fmt
);
54 vfprintf(stderr
, fmt
, arglist
);
58 static int is_vmlinux(const char *modname
)
62 if ((myname
= strrchr(modname
, '/')))
67 return strcmp(myname
, "vmlinux") == 0;
70 void *do_nofail(void *ptr
, const char *expr
)
73 fatal("modpost: Memory allocation failure: %s.\n", expr
);
78 /* A list of all modules we processed */
80 static struct module
*modules
;
82 static struct module
*find_module(char *modname
)
86 for (mod
= modules
; mod
; mod
= mod
->next
)
87 if (strcmp(mod
->name
, modname
) == 0)
92 static struct module
*new_module(char *modname
)
97 mod
= NOFAIL(malloc(sizeof(*mod
)));
98 memset(mod
, 0, sizeof(*mod
));
99 p
= NOFAIL(strdup(modname
));
101 /* strip trailing .o */
102 if ((s
= strrchr(p
, '.')) != NULL
)
103 if (strcmp(s
, ".o") == 0)
108 mod
->gpl_compatible
= -1;
115 /* A hash of all exported symbols,
116 * struct symbol is also used for lists of unresolved symbols */
118 #define SYMBOL_HASH_SIZE 1024
122 struct module
*module
;
126 unsigned int vmlinux
:1; /* 1 if symbol is defined in vmlinux */
127 unsigned int kernel
:1; /* 1 if symbol is from kernel
128 * (only for external modules) **/
129 unsigned int preloaded
:1; /* 1 if symbol from Module.symvers */
130 enum export export
; /* Type of export */
134 static struct symbol
*symbolhash
[SYMBOL_HASH_SIZE
];
136 /* This is based on the hash agorithm from gdbm, via tdb */
137 static inline unsigned int tdb_hash(const char *name
)
139 unsigned value
; /* Used to compute the hash value. */
140 unsigned i
; /* Used to cycle through random values. */
142 /* Set the initial value from the key size. */
143 for (value
= 0x238F13AF * strlen(name
), i
=0; name
[i
]; i
++)
144 value
= (value
+ (((unsigned char *)name
)[i
] << (i
*5 % 24)));
146 return (1103515243 * value
+ 12345);
150 * Allocate a new symbols for use in the hash of exported symbols or
151 * the list of unresolved symbols per module
153 static struct symbol
*alloc_symbol(const char *name
, unsigned int weak
,
156 struct symbol
*s
= NOFAIL(malloc(sizeof(*s
) + strlen(name
) + 1));
158 memset(s
, 0, sizeof(*s
));
159 strcpy(s
->name
, name
);
165 /* For the hash of exported symbols */
166 static struct symbol
*new_symbol(const char *name
, struct module
*module
,
172 hash
= tdb_hash(name
) % SYMBOL_HASH_SIZE
;
173 new = symbolhash
[hash
] = alloc_symbol(name
, 0, symbolhash
[hash
]);
174 new->module
= module
;
175 new->export
= export
;
179 static struct symbol
*find_symbol(const char *name
)
183 /* For our purposes, .foo matches foo. PPC64 needs this. */
187 for (s
= symbolhash
[tdb_hash(name
) % SYMBOL_HASH_SIZE
]; s
; s
=s
->next
) {
188 if (strcmp(s
->name
, name
) == 0)
198 { .str
= "EXPORT_SYMBOL", .export
= export_plain
},
199 { .str
= "EXPORT_UNUSED_SYMBOL", .export
= export_unused
},
200 { .str
= "EXPORT_SYMBOL_GPL", .export
= export_gpl
},
201 { .str
= "EXPORT_UNUSED_SYMBOL_GPL", .export
= export_unused_gpl
},
202 { .str
= "EXPORT_SYMBOL_GPL_FUTURE", .export
= export_gpl_future
},
203 { .str
= "(unknown)", .export
= export_unknown
},
207 static const char *export_str(enum export ex
)
209 return export_list
[ex
].str
;
212 static enum export
export_no(const char * s
)
216 return export_unknown
;
217 for (i
= 0; export_list
[i
].export
!= export_unknown
; i
++) {
218 if (strcmp(export_list
[i
].str
, s
) == 0)
219 return export_list
[i
].export
;
221 return export_unknown
;
224 static enum export
export_from_sec(struct elf_info
*elf
, Elf_Section sec
)
226 if (sec
== elf
->export_sec
)
228 else if (sec
== elf
->export_unused_sec
)
229 return export_unused
;
230 else if (sec
== elf
->export_gpl_sec
)
232 else if (sec
== elf
->export_unused_gpl_sec
)
233 return export_unused_gpl
;
234 else if (sec
== elf
->export_gpl_future_sec
)
235 return export_gpl_future
;
237 return export_unknown
;
241 * Add an exported symbol - it may have already been added without a
242 * CRC, in this case just update the CRC
244 static struct symbol
*sym_add_exported(const char *name
, struct module
*mod
,
247 struct symbol
*s
= find_symbol(name
);
250 s
= new_symbol(name
, mod
, export
);
253 warn("%s: '%s' exported twice. Previous export "
254 "was in %s%s\n", mod
->name
, name
,
256 is_vmlinux(s
->module
->name
) ?"":".ko");
260 s
->vmlinux
= is_vmlinux(mod
->name
);
266 static void sym_update_crc(const char *name
, struct module
*mod
,
267 unsigned int crc
, enum export export
)
269 struct symbol
*s
= find_symbol(name
);
272 s
= new_symbol(name
, mod
, export
);
277 void *grab_file(const char *filename
, unsigned long *size
)
283 fd
= open(filename
, O_RDONLY
);
284 if (fd
< 0 || fstat(fd
, &st
) != 0)
288 map
= mmap(NULL
, *size
, PROT_READ
|PROT_WRITE
, MAP_PRIVATE
, fd
, 0);
291 if (map
== MAP_FAILED
)
297 * Return a copy of the next line in a mmap'ed file.
298 * spaces in the beginning of the line is trimmed away.
299 * Return a pointer to a static buffer.
301 char* get_next_line(unsigned long *pos
, void *file
, unsigned long size
)
303 static char line
[4096];
306 signed char *p
= (signed char *)file
+ *pos
;
309 for (; *pos
< size
; (*pos
)++)
311 if (skip
&& isspace(*p
)) {
316 if (*p
!= '\n' && (*pos
< size
)) {
320 break; /* Too long, stop */
331 void release_file(void *file
, unsigned long size
)
336 static int parse_elf(struct elf_info
*info
, const char *filename
)
343 hdr
= grab_file(filename
, &info
->size
);
349 if (info
->size
< sizeof(*hdr
)) {
350 /* file too small, assume this is an empty .o file */
353 /* Is this a valid ELF file? */
354 if ((hdr
->e_ident
[EI_MAG0
] != ELFMAG0
) ||
355 (hdr
->e_ident
[EI_MAG1
] != ELFMAG1
) ||
356 (hdr
->e_ident
[EI_MAG2
] != ELFMAG2
) ||
357 (hdr
->e_ident
[EI_MAG3
] != ELFMAG3
)) {
358 /* Not an ELF file - silently ignore it */
361 /* Fix endianness in ELF header */
362 hdr
->e_shoff
= TO_NATIVE(hdr
->e_shoff
);
363 hdr
->e_shstrndx
= TO_NATIVE(hdr
->e_shstrndx
);
364 hdr
->e_shnum
= TO_NATIVE(hdr
->e_shnum
);
365 hdr
->e_machine
= TO_NATIVE(hdr
->e_machine
);
366 sechdrs
= (void *)hdr
+ hdr
->e_shoff
;
367 info
->sechdrs
= sechdrs
;
369 /* Fix endianness in section headers */
370 for (i
= 0; i
< hdr
->e_shnum
; i
++) {
371 sechdrs
[i
].sh_type
= TO_NATIVE(sechdrs
[i
].sh_type
);
372 sechdrs
[i
].sh_offset
= TO_NATIVE(sechdrs
[i
].sh_offset
);
373 sechdrs
[i
].sh_size
= TO_NATIVE(sechdrs
[i
].sh_size
);
374 sechdrs
[i
].sh_link
= TO_NATIVE(sechdrs
[i
].sh_link
);
375 sechdrs
[i
].sh_name
= TO_NATIVE(sechdrs
[i
].sh_name
);
377 /* Find symbol table. */
378 for (i
= 1; i
< hdr
->e_shnum
; i
++) {
379 const char *secstrings
380 = (void *)hdr
+ sechdrs
[hdr
->e_shstrndx
].sh_offset
;
383 if (sechdrs
[i
].sh_offset
> info
->size
) {
384 fatal("%s is truncated. sechdrs[i].sh_offset=%u > sizeof(*hrd)=%ul\n", filename
, (unsigned int)sechdrs
[i
].sh_offset
, sizeof(*hdr
));
387 secname
= secstrings
+ sechdrs
[i
].sh_name
;
388 if (strcmp(secname
, ".modinfo") == 0) {
389 info
->modinfo
= (void *)hdr
+ sechdrs
[i
].sh_offset
;
390 info
->modinfo_len
= sechdrs
[i
].sh_size
;
391 } else if (strcmp(secname
, "__ksymtab") == 0)
392 info
->export_sec
= i
;
393 else if (strcmp(secname
, "__ksymtab_unused") == 0)
394 info
->export_unused_sec
= i
;
395 else if (strcmp(secname
, "__ksymtab_gpl") == 0)
396 info
->export_gpl_sec
= i
;
397 else if (strcmp(secname
, "__ksymtab_unused_gpl") == 0)
398 info
->export_unused_gpl_sec
= i
;
399 else if (strcmp(secname
, "__ksymtab_gpl_future") == 0)
400 info
->export_gpl_future_sec
= i
;
402 if (sechdrs
[i
].sh_type
!= SHT_SYMTAB
)
405 info
->symtab_start
= (void *)hdr
+ sechdrs
[i
].sh_offset
;
406 info
->symtab_stop
= (void *)hdr
+ sechdrs
[i
].sh_offset
407 + sechdrs
[i
].sh_size
;
408 info
->strtab
= (void *)hdr
+
409 sechdrs
[sechdrs
[i
].sh_link
].sh_offset
;
411 if (!info
->symtab_start
) {
412 fatal("%s has no symtab?\n", filename
);
414 /* Fix endianness in symbols */
415 for (sym
= info
->symtab_start
; sym
< info
->symtab_stop
; sym
++) {
416 sym
->st_shndx
= TO_NATIVE(sym
->st_shndx
);
417 sym
->st_name
= TO_NATIVE(sym
->st_name
);
418 sym
->st_value
= TO_NATIVE(sym
->st_value
);
419 sym
->st_size
= TO_NATIVE(sym
->st_size
);
424 static void parse_elf_finish(struct elf_info
*info
)
426 release_file(info
->hdr
, info
->size
);
429 #define CRC_PFX MODULE_SYMBOL_PREFIX "__crc_"
430 #define KSYMTAB_PFX MODULE_SYMBOL_PREFIX "__ksymtab_"
432 static void handle_modversions(struct module
*mod
, struct elf_info
*info
,
433 Elf_Sym
*sym
, const char *symname
)
436 enum export export
= export_from_sec(info
, sym
->st_shndx
);
438 switch (sym
->st_shndx
) {
440 warn("\"%s\" [%s] is COMMON symbol\n", symname
, mod
->name
);
444 if (memcmp(symname
, CRC_PFX
, strlen(CRC_PFX
)) == 0) {
445 crc
= (unsigned int) sym
->st_value
;
446 sym_update_crc(symname
+ strlen(CRC_PFX
), mod
, crc
,
451 /* undefined symbol */
452 if (ELF_ST_BIND(sym
->st_info
) != STB_GLOBAL
&&
453 ELF_ST_BIND(sym
->st_info
) != STB_WEAK
)
455 /* ignore global offset table */
456 if (strcmp(symname
, "_GLOBAL_OFFSET_TABLE_") == 0)
458 /* ignore __this_module, it will be resolved shortly */
459 if (strcmp(symname
, MODULE_SYMBOL_PREFIX
"__this_module") == 0)
461 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
462 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
463 /* add compatibility with older glibc */
464 #ifndef STT_SPARC_REGISTER
465 #define STT_SPARC_REGISTER STT_REGISTER
467 if (info
->hdr
->e_machine
== EM_SPARC
||
468 info
->hdr
->e_machine
== EM_SPARCV9
) {
469 /* Ignore register directives. */
470 if (ELF_ST_TYPE(sym
->st_info
) == STT_SPARC_REGISTER
)
472 if (symname
[0] == '.') {
473 char *munged
= strdup(symname
);
475 munged
[1] = toupper(munged
[1]);
481 if (memcmp(symname
, MODULE_SYMBOL_PREFIX
,
482 strlen(MODULE_SYMBOL_PREFIX
)) == 0)
483 mod
->unres
= alloc_symbol(symname
+
484 strlen(MODULE_SYMBOL_PREFIX
),
485 ELF_ST_BIND(sym
->st_info
) == STB_WEAK
,
489 /* All exported symbols */
490 if (memcmp(symname
, KSYMTAB_PFX
, strlen(KSYMTAB_PFX
)) == 0) {
491 sym_add_exported(symname
+ strlen(KSYMTAB_PFX
), mod
,
494 if (strcmp(symname
, MODULE_SYMBOL_PREFIX
"init_module") == 0)
496 if (strcmp(symname
, MODULE_SYMBOL_PREFIX
"cleanup_module") == 0)
497 mod
->has_cleanup
= 1;
503 * Parse tag=value strings from .modinfo section
505 static char *next_string(char *string
, unsigned long *secsize
)
507 /* Skip non-zero chars */
510 if ((*secsize
)-- <= 1)
514 /* Skip any zero padding. */
517 if ((*secsize
)-- <= 1)
523 static char *get_next_modinfo(void *modinfo
, unsigned long modinfo_len
,
524 const char *tag
, char *info
)
527 unsigned int taglen
= strlen(tag
);
528 unsigned long size
= modinfo_len
;
531 size
-= info
- (char *)modinfo
;
532 modinfo
= next_string(info
, &size
);
535 for (p
= modinfo
; p
; p
= next_string(p
, &size
)) {
536 if (strncmp(p
, tag
, taglen
) == 0 && p
[taglen
] == '=')
537 return p
+ taglen
+ 1;
542 static char *get_modinfo(void *modinfo
, unsigned long modinfo_len
,
546 return get_next_modinfo(modinfo
, modinfo_len
, tag
, NULL
);
550 * Test if string s ends in string sub
553 static int strrcmp(const char *s
, const char *sub
)
561 sublen
= strlen(sub
);
563 if ((slen
== 0) || (sublen
== 0))
569 return memcmp(s
+ slen
- sublen
, sub
, sublen
);
573 * Whitelist to allow certain references to pass with no warning.
575 * If a module parameter is declared __initdata and permissions=0
576 * then this is legal despite the warning generated.
577 * We cannot see value of permissions here, so just ignore
579 * The pattern is identified by:
585 * Many drivers utilise a *driver container with references to
586 * add, remove, probe functions etc.
587 * These functions may often be marked __init and we do not want to
589 * the pattern is identified by:
590 * tosec = .init.text | .exit.text | .init.data
592 * atsym = *driver, *_template, *_sht, *_ops, *_probe, *probe_one, *_console
595 * Whitelist all references from .pci_fixup* section to .init.text
596 * This is part of the PCI init when built-in
599 * Whitelist all refereces from .text.head to .init.data
600 * Whitelist all refereces from .text.head to .init.text
603 * Some symbols belong to init section but still it is ok to reference
604 * these from non-init sections as these symbols don't have any memory
605 * allocated for them and symbol address and value are same. So even
606 * if init section is freed, its ok to reference those symbols.
607 * For ex. symbols marking the init section boundaries.
608 * This pattern is identified by
609 * refsymname = __init_begin, _sinittext, _einittext
612 * During the early init phase we have references from .init.text to
613 * .text we have an intended section mismatch - do not warn about it.
614 * See kernel_init() in init/main.c
617 * atsym = kernel_init
618 * Some symbols belong to init section but still it is ok to reference
621 * Logos used in drivers/video/logo reside in __initdata but the
622 * funtion that references them are EXPORT_SYMBOL() so cannot be
623 * marker __init. So we whitelist them here.
629 static int secref_whitelist(const char *modname
, const char *tosec
,
630 const char *fromsec
, const char *atsym
,
631 const char *refsymname
)
635 const char *pat2sym
[] = {
637 "_template", /* scsi uses *_template a lot */
638 "_sht", /* scsi also used *_sht to some extent */
646 const char *pat3refsym
[] = {
653 /* Check for pattern 1 */
654 if (strcmp(tosec
, ".init.data") != 0)
656 if (strncmp(fromsec
, ".data", strlen(".data")) != 0)
658 if (strncmp(atsym
, "__param", strlen("__param")) != 0)
664 /* Check for pattern 2 */
665 if ((strcmp(tosec
, ".init.text") != 0) &&
666 (strcmp(tosec
, ".exit.text") != 0) &&
667 (strcmp(tosec
, ".init.data") != 0))
669 if (strcmp(fromsec
, ".data") != 0)
672 for (s
= pat2sym
; *s
; s
++)
673 if (strrcmp(atsym
, *s
) == 0)
678 /* Check for pattern 3 */
679 if ((strncmp(fromsec
, ".pci_fixup", strlen(".pci_fixup")) == 0) &&
680 (strcmp(tosec
, ".init.text") == 0))
683 /* Check for pattern 4 */
684 if ((strcmp(fromsec
, ".text.head") == 0) &&
685 ((strcmp(tosec
, ".init.data") == 0) ||
686 (strcmp(tosec
, ".init.text") == 0)))
689 /* Check for pattern 5 */
690 for (s
= pat3refsym
; *s
; s
++)
691 if (strcmp(refsymname
, *s
) == 0)
694 /* Check for pattern 6 */
695 if ((strcmp(tosec
, ".init.text") == 0) &&
696 (strcmp(fromsec
, ".text") == 0) &&
697 (strcmp(refsymname
, "kernel_init") == 0))
700 /* Check for pattern 7 */
701 if ((strcmp(tosec
, ".init.data") == 0) &&
702 (strncmp(fromsec
, ".text", strlen(".text")) == 0) &&
703 (strncmp(refsymname
, "logo_", strlen("logo_")) == 0))
709 * Find symbol based on relocation record info.
710 * In some cases the symbol supplied is a valid symbol so
711 * return refsym. If st_name != 0 we assume this is a valid symbol.
712 * In other cases the symbol needs to be looked up in the symbol table
713 * based on section and address.
715 static Elf_Sym
*find_elf_symbol(struct elf_info
*elf
, Elf_Addr addr
,
720 if (relsym
->st_name
!= 0)
722 for (sym
= elf
->symtab_start
; sym
< elf
->symtab_stop
; sym
++) {
723 if (sym
->st_shndx
!= relsym
->st_shndx
)
725 if (sym
->st_value
== addr
)
731 static inline int is_arm_mapping_symbol(const char *str
)
733 return str
[0] == '$' && strchr("atd", str
[1])
734 && (str
[2] == '\0' || str
[2] == '.');
738 * If there's no name there, ignore it; likewise, ignore it if it's
739 * one of the magic symbols emitted used by current ARM tools.
741 * Otherwise if find_symbols_between() returns those symbols, they'll
742 * fail the whitelist tests and cause lots of false alarms ... fixable
743 * only by merging __exit and __init sections into __text, bloating
744 * the kernel (which is especially evil on embedded platforms).
746 static inline int is_valid_name(struct elf_info
*elf
, Elf_Sym
*sym
)
748 const char *name
= elf
->strtab
+ sym
->st_name
;
750 if (!name
|| !strlen(name
))
752 return !is_arm_mapping_symbol(name
);
756 * Find symbols before or equal addr and after addr - in the section sec.
757 * If we find two symbols with equal offset prefer one with a valid name.
758 * The ELF format may have a better way to detect what type of symbol
759 * it is, but this works for now.
761 static void find_symbols_between(struct elf_info
*elf
, Elf_Addr addr
,
763 Elf_Sym
**before
, Elf_Sym
**after
)
766 Elf_Ehdr
*hdr
= elf
->hdr
;
767 Elf_Addr beforediff
= ~0;
768 Elf_Addr afterdiff
= ~0;
769 const char *secstrings
= (void *)hdr
+
770 elf
->sechdrs
[hdr
->e_shstrndx
].sh_offset
;
775 for (sym
= elf
->symtab_start
; sym
< elf
->symtab_stop
; sym
++) {
778 if (sym
->st_shndx
>= SHN_LORESERVE
)
780 symsec
= secstrings
+ elf
->sechdrs
[sym
->st_shndx
].sh_name
;
781 if (strcmp(symsec
, sec
) != 0)
783 if (!is_valid_name(elf
, sym
))
785 if (sym
->st_value
<= addr
) {
786 if ((addr
- sym
->st_value
) < beforediff
) {
787 beforediff
= addr
- sym
->st_value
;
790 else if ((addr
- sym
->st_value
) == beforediff
) {
796 if ((sym
->st_value
- addr
) < afterdiff
) {
797 afterdiff
= sym
->st_value
- addr
;
800 else if ((sym
->st_value
- addr
) == afterdiff
) {
808 * Print a warning about a section mismatch.
809 * Try to find symbols near it so user can find it.
810 * Check whitelist before warning - it may be a false positive.
812 static void warn_sec_mismatch(const char *modname
, const char *fromsec
,
813 struct elf_info
*elf
, Elf_Sym
*sym
, Elf_Rela r
)
815 const char *refsymname
= "";
816 Elf_Sym
*before
, *after
;
818 Elf_Ehdr
*hdr
= elf
->hdr
;
819 Elf_Shdr
*sechdrs
= elf
->sechdrs
;
820 const char *secstrings
= (void *)hdr
+
821 sechdrs
[hdr
->e_shstrndx
].sh_offset
;
822 const char *secname
= secstrings
+ sechdrs
[sym
->st_shndx
].sh_name
;
824 find_symbols_between(elf
, r
.r_offset
, fromsec
, &before
, &after
);
826 refsym
= find_elf_symbol(elf
, r
.r_addend
, sym
);
827 if (refsym
&& strlen(elf
->strtab
+ refsym
->st_name
))
828 refsymname
= elf
->strtab
+ refsym
->st_name
;
830 /* check whitelist - we may ignore it */
832 secref_whitelist(modname
, secname
, fromsec
,
833 elf
->strtab
+ before
->st_name
, refsymname
))
836 if (before
&& after
) {
837 warn("%s - Section mismatch: reference to %s:%s from %s "
838 "between '%s' (at offset 0x%llx) and '%s'\n",
839 modname
, secname
, refsymname
, fromsec
,
840 elf
->strtab
+ before
->st_name
,
841 (long long)r
.r_offset
,
842 elf
->strtab
+ after
->st_name
);
844 warn("%s - Section mismatch: reference to %s:%s from %s "
845 "after '%s' (at offset 0x%llx)\n",
846 modname
, secname
, refsymname
, fromsec
,
847 elf
->strtab
+ before
->st_name
,
848 (long long)r
.r_offset
);
850 warn("%s - Section mismatch: reference to %s:%s from %s "
851 "before '%s' (at offset -0x%llx)\n",
852 modname
, secname
, refsymname
, fromsec
,
853 elf
->strtab
+ after
->st_name
,
854 (long long)r
.r_offset
);
856 warn("%s - Section mismatch: reference to %s:%s from %s "
858 modname
, secname
, fromsec
, refsymname
,
859 (long long)r
.r_offset
);
864 * A module includes a number of sections that are discarded
865 * either when loaded or when used as built-in.
866 * For loaded modules all functions marked __init and all data
867 * marked __initdata will be discarded when the module has been intialized.
868 * Likewise for modules used built-in the sections marked __exit
869 * are discarded because __exit marked function are supposed to be called
870 * only when a moduel is unloaded which never happes for built-in modules.
871 * The check_sec_ref() function traverses all relocation records
872 * to find all references to a section that reference a section that will
873 * be discarded and warns about it.
875 static void check_sec_ref(struct module
*mod
, const char *modname
,
876 struct elf_info
*elf
,
877 int section(const char*),
878 int section_ref_ok(const char *))
882 Elf_Ehdr
*hdr
= elf
->hdr
;
883 Elf_Shdr
*sechdrs
= elf
->sechdrs
;
884 const char *secstrings
= (void *)hdr
+
885 sechdrs
[hdr
->e_shstrndx
].sh_offset
;
887 /* Walk through all sections */
888 for (i
= 0; i
< hdr
->e_shnum
; i
++) {
889 const char *name
= secstrings
+ sechdrs
[i
].sh_name
;
893 /* We want to process only relocation sections and not .init */
894 if (sechdrs
[i
].sh_type
== SHT_RELA
) {
896 Elf_Rela
*start
= (void *)hdr
+ sechdrs
[i
].sh_offset
;
897 Elf_Rela
*stop
= (void*)start
+ sechdrs
[i
].sh_size
;
898 name
+= strlen(".rela");
899 if (section_ref_ok(name
))
902 for (rela
= start
; rela
< stop
; rela
++) {
903 r
.r_offset
= TO_NATIVE(rela
->r_offset
);
904 #if KERNEL_ELFCLASS == ELFCLASS64
905 if (hdr
->e_machine
== EM_MIPS
) {
906 r_sym
= ELF64_MIPS_R_SYM(rela
->r_info
);
907 r_sym
= TO_NATIVE(r_sym
);
909 r
.r_info
= TO_NATIVE(rela
->r_info
);
910 r_sym
= ELF_R_SYM(r
.r_info
);
913 r
.r_info
= TO_NATIVE(rela
->r_info
);
914 r_sym
= ELF_R_SYM(r
.r_info
);
916 r
.r_addend
= TO_NATIVE(rela
->r_addend
);
917 sym
= elf
->symtab_start
+ r_sym
;
918 /* Skip special sections */
919 if (sym
->st_shndx
>= SHN_LORESERVE
)
922 secname
= secstrings
+
923 sechdrs
[sym
->st_shndx
].sh_name
;
924 if (section(secname
))
925 warn_sec_mismatch(modname
, name
,
928 } else if (sechdrs
[i
].sh_type
== SHT_REL
) {
930 Elf_Rel
*start
= (void *)hdr
+ sechdrs
[i
].sh_offset
;
931 Elf_Rel
*stop
= (void*)start
+ sechdrs
[i
].sh_size
;
932 name
+= strlen(".rel");
933 if (section_ref_ok(name
))
936 for (rel
= start
; rel
< stop
; rel
++) {
937 r
.r_offset
= TO_NATIVE(rel
->r_offset
);
938 #if KERNEL_ELFCLASS == ELFCLASS64
939 if (hdr
->e_machine
== EM_MIPS
) {
940 r_sym
= ELF64_MIPS_R_SYM(rel
->r_info
);
941 r_sym
= TO_NATIVE(r_sym
);
943 r
.r_info
= TO_NATIVE(rel
->r_info
);
944 r_sym
= ELF_R_SYM(r
.r_info
);
947 r
.r_info
= TO_NATIVE(rel
->r_info
);
948 r_sym
= ELF_R_SYM(r
.r_info
);
951 sym
= elf
->symtab_start
+ r_sym
;
952 /* Skip special sections */
953 if (sym
->st_shndx
>= SHN_LORESERVE
)
956 secname
= secstrings
+
957 sechdrs
[sym
->st_shndx
].sh_name
;
958 if (section(secname
))
959 warn_sec_mismatch(modname
, name
,
967 * Functions used only during module init is marked __init and is stored in
968 * a .init.text section. Likewise data is marked __initdata and stored in
969 * a .init.data section.
970 * If this section is one of these sections return 1
971 * See include/linux/init.h for the details
973 static int init_section(const char *name
)
975 if (strcmp(name
, ".init") == 0)
977 if (strncmp(name
, ".init.", strlen(".init.")) == 0)
983 * Identify sections from which references to a .init section is OK.
985 * Unfortunately references to read only data that referenced .init
986 * sections had to be excluded. Almost all of these are false
987 * positives, they are created by gcc. The downside of excluding rodata
988 * is that there really are some user references from rodata to
989 * init code, e.g. drivers/video/vgacon.c:
991 * const struct consw vga_con = {
992 * con_startup: vgacon_startup,
994 * where vgacon_startup is __init. If you want to wade through the false
995 * positives, take out the check for rodata.
997 static int init_section_ref_ok(const char *name
)
1000 /* Absolute section names */
1001 const char *namelist1
[] = {
1003 ".opd", /* see comment [OPD] at exit_section_ref_ok() */
1004 ".toc1", /* used by ppc64 */
1006 ".data.rel.ro", /* used by parisc64 */
1007 ".parainstructions",
1009 "__bug_table", /* used by powerpc for BUG() */
1010 ".pci_fixup_header",
1017 ".plt", /* seen on ARCH=um build on x86_64. Harmless */
1018 "__ftr_fixup", /* powerpc cpu feature fixup */
1019 "__fw_ftr_fixup", /* powerpc firmware feature fixup */
1022 /* Start of section names */
1023 const char *namelist2
[] = {
1028 ".parainstructions",
1032 /* part of section name */
1033 const char *namelist3
[] = {
1034 ".unwind", /* sample: IA_64.unwind.init.text */
1038 for (s
= namelist1
; *s
; s
++)
1039 if (strcmp(*s
, name
) == 0)
1041 for (s
= namelist2
; *s
; s
++)
1042 if (strncmp(*s
, name
, strlen(*s
)) == 0)
1044 for (s
= namelist3
; *s
; s
++)
1045 if (strstr(name
, *s
) != NULL
)
1047 if (strrcmp(name
, ".init") == 0)
1053 * Functions used only during module exit is marked __exit and is stored in
1054 * a .exit.text section. Likewise data is marked __exitdata and stored in
1055 * a .exit.data section.
1056 * If this section is one of these sections return 1
1057 * See include/linux/init.h for the details
1059 static int exit_section(const char *name
)
1061 if (strcmp(name
, ".exit.text") == 0)
1063 if (strcmp(name
, ".exit.data") == 0)
1070 * Identify sections from which references to a .exit section is OK.
1072 * [OPD] Keith Ownes <kaos@sgi.com> commented:
1073 * For our future {in}sanity, add a comment that this is the ppc .opd
1074 * section, not the ia64 .opd section.
1075 * ia64 .opd should not point to discarded sections.
1076 * [.rodata] like for .init.text we ignore .rodata references -same reason
1078 static int exit_section_ref_ok(const char *name
)
1081 /* Absolute section names */
1082 const char *namelist1
[] = {
1087 ".opd", /* See comment [OPD] */
1088 ".toc1", /* used by ppc64 */
1091 "__bug_table", /* used by powerpc for BUG() */
1094 ".parainstructions",
1099 ".plt", /* seen on ARCH=um build on x86_64. Harmless */
1102 /* Start of section names */
1103 const char *namelist2
[] = {
1107 /* part of section name */
1108 const char *namelist3
[] = {
1109 ".unwind", /* Sample: IA_64.unwind.exit.text */
1113 for (s
= namelist1
; *s
; s
++)
1114 if (strcmp(*s
, name
) == 0)
1116 for (s
= namelist2
; *s
; s
++)
1117 if (strncmp(*s
, name
, strlen(*s
)) == 0)
1119 for (s
= namelist3
; *s
; s
++)
1120 if (strstr(name
, *s
) != NULL
)
1125 static void read_symbols(char *modname
)
1127 const char *symname
;
1131 struct elf_info info
= { };
1134 if (!parse_elf(&info
, modname
))
1137 mod
= new_module(modname
);
1139 /* When there's no vmlinux, don't print warnings about
1140 * unresolved symbols (since there'll be too many ;) */
1141 if (is_vmlinux(modname
)) {
1146 license
= get_modinfo(info
.modinfo
, info
.modinfo_len
, "license");
1148 if (license_is_gpl_compatible(license
))
1149 mod
->gpl_compatible
= 1;
1151 mod
->gpl_compatible
= 0;
1154 license
= get_next_modinfo(info
.modinfo
, info
.modinfo_len
,
1155 "license", license
);
1158 for (sym
= info
.symtab_start
; sym
< info
.symtab_stop
; sym
++) {
1159 symname
= info
.strtab
+ sym
->st_name
;
1161 handle_modversions(mod
, &info
, sym
, symname
);
1162 handle_moddevtable(mod
, &info
, sym
, symname
);
1164 check_sec_ref(mod
, modname
, &info
, init_section
, init_section_ref_ok
);
1165 check_sec_ref(mod
, modname
, &info
, exit_section
, exit_section_ref_ok
);
1167 version
= get_modinfo(info
.modinfo
, info
.modinfo_len
, "version");
1169 maybe_frob_rcs_version(modname
, version
, info
.modinfo
,
1170 version
- (char *)info
.hdr
);
1171 if (version
|| (all_versions
&& !is_vmlinux(modname
)))
1172 get_src_version(modname
, mod
->srcversion
,
1173 sizeof(mod
->srcversion
)-1);
1175 parse_elf_finish(&info
);
1177 /* Our trick to get versioning for struct_module - it's
1178 * never passed as an argument to an exported function, so
1179 * the automatic versioning doesn't pick it up, but it's really
1180 * important anyhow */
1182 mod
->unres
= alloc_symbol("struct_module", 0, mod
->unres
);
1187 /* We first write the generated file into memory using the
1188 * following helper, then compare to the file on disk and
1189 * only update the later if anything changed */
1191 void __attribute__((format(printf
, 2, 3))) buf_printf(struct buffer
*buf
,
1192 const char *fmt
, ...)
1199 len
= vsnprintf(tmp
, SZ
, fmt
, ap
);
1200 buf_write(buf
, tmp
, len
);
1204 void buf_write(struct buffer
*buf
, const char *s
, int len
)
1206 if (buf
->size
- buf
->pos
< len
) {
1207 buf
->size
+= len
+ SZ
;
1208 buf
->p
= realloc(buf
->p
, buf
->size
);
1210 strncpy(buf
->p
+ buf
->pos
, s
, len
);
1214 static void check_for_gpl_usage(enum export exp
, const char *m
, const char *s
)
1216 const char *e
= is_vmlinux(m
) ?"":".ko";
1220 fatal("modpost: GPL-incompatible module %s%s "
1221 "uses GPL-only symbol '%s'\n", m
, e
, s
);
1223 case export_unused_gpl
:
1224 fatal("modpost: GPL-incompatible module %s%s "
1225 "uses GPL-only symbol marked UNUSED '%s'\n", m
, e
, s
);
1227 case export_gpl_future
:
1228 warn("modpost: GPL-incompatible module %s%s "
1229 "uses future GPL-only symbol '%s'\n", m
, e
, s
);
1233 case export_unknown
:
1239 static void check_for_unused(enum export exp
, const char* m
, const char* s
)
1241 const char *e
= is_vmlinux(m
) ?"":".ko";
1245 case export_unused_gpl
:
1246 warn("modpost: module %s%s "
1247 "uses symbol '%s' marked UNUSED\n", m
, e
, s
);
1255 static void check_exports(struct module
*mod
)
1257 struct symbol
*s
, *exp
;
1259 for (s
= mod
->unres
; s
; s
= s
->next
) {
1260 const char *basename
;
1261 exp
= find_symbol(s
->name
);
1262 if (!exp
|| exp
->module
== mod
)
1264 basename
= strrchr(mod
->name
, '/');
1268 basename
= mod
->name
;
1269 if (!mod
->gpl_compatible
)
1270 check_for_gpl_usage(exp
->export
, basename
, exp
->name
);
1271 check_for_unused(exp
->export
, basename
, exp
->name
);
1276 * Header for the generated file
1278 static void add_header(struct buffer
*b
, struct module
*mod
)
1280 buf_printf(b
, "#include <linux/module.h>\n");
1281 buf_printf(b
, "#include <linux/vermagic.h>\n");
1282 buf_printf(b
, "#include <linux/compiler.h>\n");
1283 buf_printf(b
, "\n");
1284 buf_printf(b
, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
1285 buf_printf(b
, "\n");
1286 buf_printf(b
, "struct module __this_module\n");
1287 buf_printf(b
, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
1288 buf_printf(b
, " .name = KBUILD_MODNAME,\n");
1290 buf_printf(b
, " .init = init_module,\n");
1291 if (mod
->has_cleanup
)
1292 buf_printf(b
, "#ifdef CONFIG_MODULE_UNLOAD\n"
1293 " .exit = cleanup_module,\n"
1295 buf_printf(b
, "};\n");
1299 * Record CRCs for unresolved symbols
1301 static int add_versions(struct buffer
*b
, struct module
*mod
)
1303 struct symbol
*s
, *exp
;
1306 for (s
= mod
->unres
; s
; s
= s
->next
) {
1307 exp
= find_symbol(s
->name
);
1308 if (!exp
|| exp
->module
== mod
) {
1309 if (have_vmlinux
&& !s
->weak
) {
1310 warn("\"%s\" [%s.ko] undefined!\n",
1311 s
->name
, mod
->name
);
1312 err
= warn_unresolved
? 0 : 1;
1316 s
->module
= exp
->module
;
1317 s
->crc_valid
= exp
->crc_valid
;
1324 buf_printf(b
, "\n");
1325 buf_printf(b
, "static const struct modversion_info ____versions[]\n");
1326 buf_printf(b
, "__attribute_used__\n");
1327 buf_printf(b
, "__attribute__((section(\"__versions\"))) = {\n");
1329 for (s
= mod
->unres
; s
; s
= s
->next
) {
1333 if (!s
->crc_valid
) {
1334 warn("\"%s\" [%s.ko] has no CRC!\n",
1335 s
->name
, mod
->name
);
1338 buf_printf(b
, "\t{ %#8x, \"%s\" },\n", s
->crc
, s
->name
);
1341 buf_printf(b
, "};\n");
1346 static void add_depends(struct buffer
*b
, struct module
*mod
,
1347 struct module
*modules
)
1353 for (m
= modules
; m
; m
= m
->next
) {
1354 m
->seen
= is_vmlinux(m
->name
);
1357 buf_printf(b
, "\n");
1358 buf_printf(b
, "static const char __module_depends[]\n");
1359 buf_printf(b
, "__attribute_used__\n");
1360 buf_printf(b
, "__attribute__((section(\".modinfo\"))) =\n");
1361 buf_printf(b
, "\"depends=");
1362 for (s
= mod
->unres
; s
; s
= s
->next
) {
1367 if (s
->module
->seen
)
1370 s
->module
->seen
= 1;
1371 if ((p
= strrchr(s
->module
->name
, '/')) != NULL
)
1374 p
= s
->module
->name
;
1375 buf_printf(b
, "%s%s", first
? "" : ",", p
);
1378 buf_printf(b
, "\";\n");
1381 static void add_srcversion(struct buffer
*b
, struct module
*mod
)
1383 if (mod
->srcversion
[0]) {
1384 buf_printf(b
, "\n");
1385 buf_printf(b
, "MODULE_INFO(srcversion, \"%s\");\n",
1390 static void write_if_changed(struct buffer
*b
, const char *fname
)
1396 file
= fopen(fname
, "r");
1400 if (fstat(fileno(file
), &st
) < 0)
1403 if (st
.st_size
!= b
->pos
)
1406 tmp
= NOFAIL(malloc(b
->pos
));
1407 if (fread(tmp
, 1, b
->pos
, file
) != b
->pos
)
1410 if (memcmp(tmp
, b
->p
, b
->pos
) != 0)
1422 file
= fopen(fname
, "w");
1427 if (fwrite(b
->p
, 1, b
->pos
, file
) != b
->pos
) {
1434 /* parse Module.symvers file. line format:
1435 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
1437 static void read_dump(const char *fname
, unsigned int kernel
)
1439 unsigned long size
, pos
= 0;
1440 void *file
= grab_file(fname
, &size
);
1444 /* No symbol versions, silently ignore */
1447 while ((line
= get_next_line(&pos
, file
, size
))) {
1448 char *symname
, *modname
, *d
, *export
, *end
;
1453 if (!(symname
= strchr(line
, '\t')))
1456 if (!(modname
= strchr(symname
, '\t')))
1459 if ((export
= strchr(modname
, '\t')) != NULL
)
1461 if (export
&& ((end
= strchr(export
, '\t')) != NULL
))
1463 crc
= strtoul(line
, &d
, 16);
1464 if (*symname
== '\0' || *modname
== '\0' || *d
!= '\0')
1467 if (!(mod
= find_module(modname
))) {
1468 if (is_vmlinux(modname
)) {
1471 mod
= new_module(NOFAIL(strdup(modname
)));
1474 s
= sym_add_exported(symname
, mod
, export_no(export
));
1477 sym_update_crc(symname
, mod
, crc
, export_no(export
));
1481 fatal("parse error in symbol dump file\n");
1484 /* For normal builds always dump all symbols.
1485 * For external modules only dump symbols
1486 * that are not read from kernel Module.symvers.
1488 static int dump_sym(struct symbol
*sym
)
1490 if (!external_module
)
1492 if (sym
->vmlinux
|| sym
->kernel
)
1497 static void write_dump(const char *fname
)
1499 struct buffer buf
= { };
1500 struct symbol
*symbol
;
1503 for (n
= 0; n
< SYMBOL_HASH_SIZE
; n
++) {
1504 symbol
= symbolhash
[n
];
1506 if (dump_sym(symbol
))
1507 buf_printf(&buf
, "0x%08x\t%s\t%s\t%s\n",
1508 symbol
->crc
, symbol
->name
,
1509 symbol
->module
->name
,
1510 export_str(symbol
->export
));
1511 symbol
= symbol
->next
;
1514 write_if_changed(&buf
, fname
);
1517 int main(int argc
, char **argv
)
1520 struct buffer buf
= { };
1522 char *kernel_read
= NULL
, *module_read
= NULL
;
1523 char *dump_write
= NULL
;
1527 while ((opt
= getopt(argc
, argv
, "i:I:mo:aw")) != -1) {
1530 kernel_read
= optarg
;
1533 module_read
= optarg
;
1534 external_module
= 1;
1540 dump_write
= optarg
;
1546 warn_unresolved
= 1;
1554 read_dump(kernel_read
, 1);
1556 read_dump(module_read
, 0);
1558 while (optind
< argc
) {
1559 read_symbols(argv
[optind
++]);
1562 for (mod
= modules
; mod
; mod
= mod
->next
) {
1570 for (mod
= modules
; mod
; mod
= mod
->next
) {
1576 add_header(&buf
, mod
);
1577 err
|= add_versions(&buf
, mod
);
1578 add_depends(&buf
, mod
, modules
);
1579 add_moddevtable(&buf
, mod
);
1580 add_srcversion(&buf
, mod
);
1582 sprintf(fname
, "%s.mod.c", mod
->name
);
1583 write_if_changed(&buf
, fname
);
1587 write_dump(dump_write
);