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 /* Warn about section mismatch in vmlinux if set to 1 */
27 static int vmlinux_section_warnings
= 1;
28 /* Only warn about unresolved symbols */
29 static int warn_unresolved
= 0;
30 /* How a symbol is exported */
32 export_plain
, export_unused
, export_gpl
,
33 export_unused_gpl
, export_gpl_future
, export_unknown
36 void fatal(const char *fmt
, ...)
40 fprintf(stderr
, "FATAL: ");
42 va_start(arglist
, fmt
);
43 vfprintf(stderr
, fmt
, arglist
);
49 void warn(const char *fmt
, ...)
53 fprintf(stderr
, "WARNING: ");
55 va_start(arglist
, fmt
);
56 vfprintf(stderr
, fmt
, arglist
);
60 void merror(const char *fmt
, ...)
64 fprintf(stderr
, "ERROR: ");
66 va_start(arglist
, fmt
);
67 vfprintf(stderr
, fmt
, arglist
);
71 static int is_vmlinux(const char *modname
)
75 if ((myname
= strrchr(modname
, '/')))
80 return (strcmp(myname
, "vmlinux") == 0) ||
81 (strcmp(myname
, "vmlinux.o") == 0);
84 void *do_nofail(void *ptr
, const char *expr
)
87 fatal("modpost: Memory allocation failure: %s.\n", expr
);
92 /* A list of all modules we processed */
94 static struct module
*modules
;
96 static struct module
*find_module(char *modname
)
100 for (mod
= modules
; mod
; mod
= mod
->next
)
101 if (strcmp(mod
->name
, modname
) == 0)
106 static struct module
*new_module(char *modname
)
111 mod
= NOFAIL(malloc(sizeof(*mod
)));
112 memset(mod
, 0, sizeof(*mod
));
113 p
= NOFAIL(strdup(modname
));
115 /* strip trailing .o */
116 if ((s
= strrchr(p
, '.')) != NULL
)
117 if (strcmp(s
, ".o") == 0)
122 mod
->gpl_compatible
= -1;
129 /* A hash of all exported symbols,
130 * struct symbol is also used for lists of unresolved symbols */
132 #define SYMBOL_HASH_SIZE 1024
136 struct module
*module
;
140 unsigned int vmlinux
:1; /* 1 if symbol is defined in vmlinux */
141 unsigned int kernel
:1; /* 1 if symbol is from kernel
142 * (only for external modules) **/
143 unsigned int preloaded
:1; /* 1 if symbol from Module.symvers */
144 enum export export
; /* Type of export */
148 static struct symbol
*symbolhash
[SYMBOL_HASH_SIZE
];
150 /* This is based on the hash agorithm from gdbm, via tdb */
151 static inline unsigned int tdb_hash(const char *name
)
153 unsigned value
; /* Used to compute the hash value. */
154 unsigned i
; /* Used to cycle through random values. */
156 /* Set the initial value from the key size. */
157 for (value
= 0x238F13AF * strlen(name
), i
=0; name
[i
]; i
++)
158 value
= (value
+ (((unsigned char *)name
)[i
] << (i
*5 % 24)));
160 return (1103515243 * value
+ 12345);
164 * Allocate a new symbols for use in the hash of exported symbols or
165 * the list of unresolved symbols per module
167 static struct symbol
*alloc_symbol(const char *name
, unsigned int weak
,
170 struct symbol
*s
= NOFAIL(malloc(sizeof(*s
) + strlen(name
) + 1));
172 memset(s
, 0, sizeof(*s
));
173 strcpy(s
->name
, name
);
179 /* For the hash of exported symbols */
180 static struct symbol
*new_symbol(const char *name
, struct module
*module
,
186 hash
= tdb_hash(name
) % SYMBOL_HASH_SIZE
;
187 new = symbolhash
[hash
] = alloc_symbol(name
, 0, symbolhash
[hash
]);
188 new->module
= module
;
189 new->export
= export
;
193 static struct symbol
*find_symbol(const char *name
)
197 /* For our purposes, .foo matches foo. PPC64 needs this. */
201 for (s
= symbolhash
[tdb_hash(name
) % SYMBOL_HASH_SIZE
]; s
; s
=s
->next
) {
202 if (strcmp(s
->name
, name
) == 0)
212 { .str
= "EXPORT_SYMBOL", .export
= export_plain
},
213 { .str
= "EXPORT_UNUSED_SYMBOL", .export
= export_unused
},
214 { .str
= "EXPORT_SYMBOL_GPL", .export
= export_gpl
},
215 { .str
= "EXPORT_UNUSED_SYMBOL_GPL", .export
= export_unused_gpl
},
216 { .str
= "EXPORT_SYMBOL_GPL_FUTURE", .export
= export_gpl_future
},
217 { .str
= "(unknown)", .export
= export_unknown
},
221 static const char *export_str(enum export ex
)
223 return export_list
[ex
].str
;
226 static enum export
export_no(const char * s
)
230 return export_unknown
;
231 for (i
= 0; export_list
[i
].export
!= export_unknown
; i
++) {
232 if (strcmp(export_list
[i
].str
, s
) == 0)
233 return export_list
[i
].export
;
235 return export_unknown
;
238 static enum export
export_from_sec(struct elf_info
*elf
, Elf_Section sec
)
240 if (sec
== elf
->export_sec
)
242 else if (sec
== elf
->export_unused_sec
)
243 return export_unused
;
244 else if (sec
== elf
->export_gpl_sec
)
246 else if (sec
== elf
->export_unused_gpl_sec
)
247 return export_unused_gpl
;
248 else if (sec
== elf
->export_gpl_future_sec
)
249 return export_gpl_future
;
251 return export_unknown
;
255 * Add an exported symbol - it may have already been added without a
256 * CRC, in this case just update the CRC
258 static struct symbol
*sym_add_exported(const char *name
, struct module
*mod
,
261 struct symbol
*s
= find_symbol(name
);
264 s
= new_symbol(name
, mod
, export
);
267 warn("%s: '%s' exported twice. Previous export "
268 "was in %s%s\n", mod
->name
, name
,
270 is_vmlinux(s
->module
->name
) ?"":".ko");
274 s
->vmlinux
= is_vmlinux(mod
->name
);
280 static void sym_update_crc(const char *name
, struct module
*mod
,
281 unsigned int crc
, enum export export
)
283 struct symbol
*s
= find_symbol(name
);
286 s
= new_symbol(name
, mod
, export
);
291 void *grab_file(const char *filename
, unsigned long *size
)
297 fd
= open(filename
, O_RDONLY
);
298 if (fd
< 0 || fstat(fd
, &st
) != 0)
302 map
= mmap(NULL
, *size
, PROT_READ
|PROT_WRITE
, MAP_PRIVATE
, fd
, 0);
305 if (map
== MAP_FAILED
)
311 * Return a copy of the next line in a mmap'ed file.
312 * spaces in the beginning of the line is trimmed away.
313 * Return a pointer to a static buffer.
315 char* get_next_line(unsigned long *pos
, void *file
, unsigned long size
)
317 static char line
[4096];
320 signed char *p
= (signed char *)file
+ *pos
;
323 for (; *pos
< size
; (*pos
)++)
325 if (skip
&& isspace(*p
)) {
330 if (*p
!= '\n' && (*pos
< size
)) {
334 break; /* Too long, stop */
345 void release_file(void *file
, unsigned long size
)
350 static int parse_elf(struct elf_info
*info
, const char *filename
)
357 hdr
= grab_file(filename
, &info
->size
);
363 if (info
->size
< sizeof(*hdr
)) {
364 /* file too small, assume this is an empty .o file */
367 /* Is this a valid ELF file? */
368 if ((hdr
->e_ident
[EI_MAG0
] != ELFMAG0
) ||
369 (hdr
->e_ident
[EI_MAG1
] != ELFMAG1
) ||
370 (hdr
->e_ident
[EI_MAG2
] != ELFMAG2
) ||
371 (hdr
->e_ident
[EI_MAG3
] != ELFMAG3
)) {
372 /* Not an ELF file - silently ignore it */
375 /* Fix endianness in ELF header */
376 hdr
->e_shoff
= TO_NATIVE(hdr
->e_shoff
);
377 hdr
->e_shstrndx
= TO_NATIVE(hdr
->e_shstrndx
);
378 hdr
->e_shnum
= TO_NATIVE(hdr
->e_shnum
);
379 hdr
->e_machine
= TO_NATIVE(hdr
->e_machine
);
380 hdr
->e_type
= TO_NATIVE(hdr
->e_type
);
381 sechdrs
= (void *)hdr
+ hdr
->e_shoff
;
382 info
->sechdrs
= sechdrs
;
384 /* Fix endianness in section headers */
385 for (i
= 0; i
< hdr
->e_shnum
; i
++) {
386 sechdrs
[i
].sh_type
= TO_NATIVE(sechdrs
[i
].sh_type
);
387 sechdrs
[i
].sh_offset
= TO_NATIVE(sechdrs
[i
].sh_offset
);
388 sechdrs
[i
].sh_size
= TO_NATIVE(sechdrs
[i
].sh_size
);
389 sechdrs
[i
].sh_link
= TO_NATIVE(sechdrs
[i
].sh_link
);
390 sechdrs
[i
].sh_name
= TO_NATIVE(sechdrs
[i
].sh_name
);
391 sechdrs
[i
].sh_info
= TO_NATIVE(sechdrs
[i
].sh_info
);
392 sechdrs
[i
].sh_addr
= TO_NATIVE(sechdrs
[i
].sh_addr
);
394 /* Find symbol table. */
395 for (i
= 1; i
< hdr
->e_shnum
; i
++) {
396 const char *secstrings
397 = (void *)hdr
+ sechdrs
[hdr
->e_shstrndx
].sh_offset
;
400 if (sechdrs
[i
].sh_offset
> info
->size
) {
401 fatal("%s is truncated. sechdrs[i].sh_offset=%u > sizeof(*hrd)=%ul\n", filename
, (unsigned int)sechdrs
[i
].sh_offset
, sizeof(*hdr
));
404 secname
= secstrings
+ sechdrs
[i
].sh_name
;
405 if (strcmp(secname
, ".modinfo") == 0) {
406 info
->modinfo
= (void *)hdr
+ sechdrs
[i
].sh_offset
;
407 info
->modinfo_len
= sechdrs
[i
].sh_size
;
408 } else if (strcmp(secname
, "__ksymtab") == 0)
409 info
->export_sec
= i
;
410 else if (strcmp(secname
, "__ksymtab_unused") == 0)
411 info
->export_unused_sec
= i
;
412 else if (strcmp(secname
, "__ksymtab_gpl") == 0)
413 info
->export_gpl_sec
= i
;
414 else if (strcmp(secname
, "__ksymtab_unused_gpl") == 0)
415 info
->export_unused_gpl_sec
= i
;
416 else if (strcmp(secname
, "__ksymtab_gpl_future") == 0)
417 info
->export_gpl_future_sec
= i
;
419 if (sechdrs
[i
].sh_type
!= SHT_SYMTAB
)
422 info
->symtab_start
= (void *)hdr
+ sechdrs
[i
].sh_offset
;
423 info
->symtab_stop
= (void *)hdr
+ sechdrs
[i
].sh_offset
424 + sechdrs
[i
].sh_size
;
425 info
->strtab
= (void *)hdr
+
426 sechdrs
[sechdrs
[i
].sh_link
].sh_offset
;
428 if (!info
->symtab_start
) {
429 fatal("%s has no symtab?\n", filename
);
431 /* Fix endianness in symbols */
432 for (sym
= info
->symtab_start
; sym
< info
->symtab_stop
; sym
++) {
433 sym
->st_shndx
= TO_NATIVE(sym
->st_shndx
);
434 sym
->st_name
= TO_NATIVE(sym
->st_name
);
435 sym
->st_value
= TO_NATIVE(sym
->st_value
);
436 sym
->st_size
= TO_NATIVE(sym
->st_size
);
441 static void parse_elf_finish(struct elf_info
*info
)
443 release_file(info
->hdr
, info
->size
);
446 #define CRC_PFX MODULE_SYMBOL_PREFIX "__crc_"
447 #define KSYMTAB_PFX MODULE_SYMBOL_PREFIX "__ksymtab_"
449 static void handle_modversions(struct module
*mod
, struct elf_info
*info
,
450 Elf_Sym
*sym
, const char *symname
)
453 enum export export
= export_from_sec(info
, sym
->st_shndx
);
455 switch (sym
->st_shndx
) {
457 warn("\"%s\" [%s] is COMMON symbol\n", symname
, mod
->name
);
461 if (memcmp(symname
, CRC_PFX
, strlen(CRC_PFX
)) == 0) {
462 crc
= (unsigned int) sym
->st_value
;
463 sym_update_crc(symname
+ strlen(CRC_PFX
), mod
, crc
,
468 /* undefined symbol */
469 if (ELF_ST_BIND(sym
->st_info
) != STB_GLOBAL
&&
470 ELF_ST_BIND(sym
->st_info
) != STB_WEAK
)
472 /* ignore global offset table */
473 if (strcmp(symname
, "_GLOBAL_OFFSET_TABLE_") == 0)
475 /* ignore __this_module, it will be resolved shortly */
476 if (strcmp(symname
, MODULE_SYMBOL_PREFIX
"__this_module") == 0)
478 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
479 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
480 /* add compatibility with older glibc */
481 #ifndef STT_SPARC_REGISTER
482 #define STT_SPARC_REGISTER STT_REGISTER
484 if (info
->hdr
->e_machine
== EM_SPARC
||
485 info
->hdr
->e_machine
== EM_SPARCV9
) {
486 /* Ignore register directives. */
487 if (ELF_ST_TYPE(sym
->st_info
) == STT_SPARC_REGISTER
)
489 if (symname
[0] == '.') {
490 char *munged
= strdup(symname
);
492 munged
[1] = toupper(munged
[1]);
498 if (memcmp(symname
, MODULE_SYMBOL_PREFIX
,
499 strlen(MODULE_SYMBOL_PREFIX
)) == 0)
500 mod
->unres
= alloc_symbol(symname
+
501 strlen(MODULE_SYMBOL_PREFIX
),
502 ELF_ST_BIND(sym
->st_info
) == STB_WEAK
,
506 /* All exported symbols */
507 if (memcmp(symname
, KSYMTAB_PFX
, strlen(KSYMTAB_PFX
)) == 0) {
508 sym_add_exported(symname
+ strlen(KSYMTAB_PFX
), mod
,
511 if (strcmp(symname
, MODULE_SYMBOL_PREFIX
"init_module") == 0)
513 if (strcmp(symname
, MODULE_SYMBOL_PREFIX
"cleanup_module") == 0)
514 mod
->has_cleanup
= 1;
520 * Parse tag=value strings from .modinfo section
522 static char *next_string(char *string
, unsigned long *secsize
)
524 /* Skip non-zero chars */
527 if ((*secsize
)-- <= 1)
531 /* Skip any zero padding. */
534 if ((*secsize
)-- <= 1)
540 static char *get_next_modinfo(void *modinfo
, unsigned long modinfo_len
,
541 const char *tag
, char *info
)
544 unsigned int taglen
= strlen(tag
);
545 unsigned long size
= modinfo_len
;
548 size
-= info
- (char *)modinfo
;
549 modinfo
= next_string(info
, &size
);
552 for (p
= modinfo
; p
; p
= next_string(p
, &size
)) {
553 if (strncmp(p
, tag
, taglen
) == 0 && p
[taglen
] == '=')
554 return p
+ taglen
+ 1;
559 static char *get_modinfo(void *modinfo
, unsigned long modinfo_len
,
563 return get_next_modinfo(modinfo
, modinfo_len
, tag
, NULL
);
567 * Test if string s ends in string sub
570 static int strrcmp(const char *s
, const char *sub
)
578 sublen
= strlen(sub
);
580 if ((slen
== 0) || (sublen
== 0))
586 return memcmp(s
+ slen
- sublen
, sub
, sublen
);
590 * Functions used only during module init is marked __init and is stored in
591 * a .init.text section. Likewise data is marked __initdata and stored in
592 * a .init.data section.
593 * If this section is one of these sections return 1
594 * See include/linux/init.h for the details
596 static int init_section(const char *name
)
598 if (strcmp(name
, ".init") == 0)
600 if (strncmp(name
, ".init.", strlen(".init.")) == 0)
606 * Functions used only during module exit is marked __exit and is stored in
607 * a .exit.text section. Likewise data is marked __exitdata and stored in
608 * a .exit.data section.
609 * If this section is one of these sections return 1
610 * See include/linux/init.h for the details
612 static int exit_section(const char *name
)
614 if (strcmp(name
, ".exit.text") == 0)
616 if (strcmp(name
, ".exit.data") == 0)
623 * Data sections are named like this:
624 * .data | .data.rel | .data.rel.*
625 * Return 1 if the specified section is a data section
627 static int data_section(const char *name
)
629 if ((strcmp(name
, ".data") == 0) ||
630 (strcmp(name
, ".data.rel") == 0) ||
631 (strncmp(name
, ".data.rel.", strlen(".data.rel.")) == 0))
638 * Whitelist to allow certain references to pass with no warning.
641 * Do not warn if funtion/data are marked with __init_refok/__initdata_refok.
642 * The pattern is identified by:
643 * fromsec = .text.init.refok | .data.init.refok
646 * If a module parameter is declared __initdata and permissions=0
647 * then this is legal despite the warning generated.
648 * We cannot see value of permissions here, so just ignore
650 * The pattern is identified by:
656 * Many drivers utilise a *driver container with references to
657 * add, remove, probe functions etc.
658 * These functions may often be marked __init and we do not want to
660 * the pattern is identified by:
661 * tosec = init or exit section
662 * fromsec = data section
663 * atsym = *driver, *_template, *_sht, *_ops, *_probe, *probe_one, *_console, *_timer
666 * Whitelist all refereces from .text.head to .init.data
667 * Whitelist all refereces from .text.head to .init.text
670 * Some symbols belong to init section but still it is ok to reference
671 * these from non-init sections as these symbols don't have any memory
672 * allocated for them and symbol address and value are same. So even
673 * if init section is freed, its ok to reference those symbols.
674 * For ex. symbols marking the init section boundaries.
675 * This pattern is identified by
676 * refsymname = __init_begin, _sinittext, _einittext
679 static int secref_whitelist(const char *modname
, const char *tosec
,
680 const char *fromsec
, const char *atsym
,
681 const char *refsymname
)
684 const char *pat2sym
[] = {
686 "_template", /* scsi uses *_template a lot */
687 "_timer", /* arm uses ops structures named _timer a lot */
688 "_sht", /* scsi also used *_sht to some extent */
696 const char *pat3refsym
[] = {
703 /* Check for pattern 0 */
704 if ((strcmp(fromsec
, ".text.init.refok") == 0) ||
705 (strcmp(fromsec
, ".data.init.refok") == 0))
708 /* Check for pattern 1 */
709 if ((strcmp(tosec
, ".init.data") == 0) &&
710 (strncmp(fromsec
, ".data", strlen(".data")) == 0) &&
711 (strncmp(atsym
, "__param", strlen("__param")) == 0))
714 /* Check for pattern 2 */
715 if ((init_section(tosec
) || exit_section(tosec
)) && data_section(fromsec
))
716 for (s
= pat2sym
; *s
; s
++)
717 if (strrcmp(atsym
, *s
) == 0)
720 /* Check for pattern 3 */
721 if ((strcmp(fromsec
, ".text.head") == 0) &&
722 ((strcmp(tosec
, ".init.data") == 0) ||
723 (strcmp(tosec
, ".init.text") == 0)))
726 /* Check for pattern 4 */
727 for (s
= pat3refsym
; *s
; s
++)
728 if (strcmp(refsymname
, *s
) == 0)
735 * Find symbol based on relocation record info.
736 * In some cases the symbol supplied is a valid symbol so
737 * return refsym. If st_name != 0 we assume this is a valid symbol.
738 * In other cases the symbol needs to be looked up in the symbol table
739 * based on section and address.
741 static Elf_Sym
*find_elf_symbol(struct elf_info
*elf
, Elf_Addr addr
,
746 if (relsym
->st_name
!= 0)
748 for (sym
= elf
->symtab_start
; sym
< elf
->symtab_stop
; sym
++) {
749 if (sym
->st_shndx
!= relsym
->st_shndx
)
751 if (ELF_ST_TYPE(sym
->st_info
) == STT_SECTION
)
753 if (sym
->st_value
== addr
)
759 static inline int is_arm_mapping_symbol(const char *str
)
761 return str
[0] == '$' && strchr("atd", str
[1])
762 && (str
[2] == '\0' || str
[2] == '.');
766 * If there's no name there, ignore it; likewise, ignore it if it's
767 * one of the magic symbols emitted used by current ARM tools.
769 * Otherwise if find_symbols_between() returns those symbols, they'll
770 * fail the whitelist tests and cause lots of false alarms ... fixable
771 * only by merging __exit and __init sections into __text, bloating
772 * the kernel (which is especially evil on embedded platforms).
774 static inline int is_valid_name(struct elf_info
*elf
, Elf_Sym
*sym
)
776 const char *name
= elf
->strtab
+ sym
->st_name
;
778 if (!name
|| !strlen(name
))
780 return !is_arm_mapping_symbol(name
);
784 * Find symbols before or equal addr and after addr - in the section sec.
785 * If we find two symbols with equal offset prefer one with a valid name.
786 * The ELF format may have a better way to detect what type of symbol
787 * it is, but this works for now.
789 static void find_symbols_between(struct elf_info
*elf
, Elf_Addr addr
,
791 Elf_Sym
**before
, Elf_Sym
**after
)
794 Elf_Ehdr
*hdr
= elf
->hdr
;
795 Elf_Addr beforediff
= ~0;
796 Elf_Addr afterdiff
= ~0;
797 const char *secstrings
= (void *)hdr
+
798 elf
->sechdrs
[hdr
->e_shstrndx
].sh_offset
;
803 for (sym
= elf
->symtab_start
; sym
< elf
->symtab_stop
; sym
++) {
806 if (sym
->st_shndx
>= SHN_LORESERVE
)
808 symsec
= secstrings
+ elf
->sechdrs
[sym
->st_shndx
].sh_name
;
809 if (strcmp(symsec
, sec
) != 0)
811 if (!is_valid_name(elf
, sym
))
813 if (sym
->st_value
<= addr
) {
814 if ((addr
- sym
->st_value
) < beforediff
) {
815 beforediff
= addr
- sym
->st_value
;
818 else if ((addr
- sym
->st_value
) == beforediff
) {
824 if ((sym
->st_value
- addr
) < afterdiff
) {
825 afterdiff
= sym
->st_value
- addr
;
828 else if ((sym
->st_value
- addr
) == afterdiff
) {
836 * Print a warning about a section mismatch.
837 * Try to find symbols near it so user can find it.
838 * Check whitelist before warning - it may be a false positive.
840 static void warn_sec_mismatch(const char *modname
, const char *fromsec
,
841 struct elf_info
*elf
, Elf_Sym
*sym
, Elf_Rela r
)
843 const char *refsymname
= "";
844 Elf_Sym
*before
, *after
;
846 Elf_Ehdr
*hdr
= elf
->hdr
;
847 Elf_Shdr
*sechdrs
= elf
->sechdrs
;
848 const char *secstrings
= (void *)hdr
+
849 sechdrs
[hdr
->e_shstrndx
].sh_offset
;
850 const char *secname
= secstrings
+ sechdrs
[sym
->st_shndx
].sh_name
;
852 find_symbols_between(elf
, r
.r_offset
, fromsec
, &before
, &after
);
854 refsym
= find_elf_symbol(elf
, r
.r_addend
, sym
);
855 if (refsym
&& strlen(elf
->strtab
+ refsym
->st_name
))
856 refsymname
= elf
->strtab
+ refsym
->st_name
;
858 /* check whitelist - we may ignore it */
860 secref_whitelist(modname
, secname
, fromsec
,
861 elf
->strtab
+ before
->st_name
, refsymname
))
864 if (before
&& after
) {
865 warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s "
866 "(between '%s' and '%s')\n",
867 modname
, fromsec
, (unsigned long long)r
.r_offset
,
869 elf
->strtab
+ before
->st_name
,
870 elf
->strtab
+ after
->st_name
);
872 warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s "
874 modname
, fromsec
, (unsigned long long)r
.r_offset
,
876 elf
->strtab
+ before
->st_name
);
878 warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s "
879 "before '%s' (at offset -0x%llx)\n",
880 modname
, fromsec
, (unsigned long long)r
.r_offset
,
882 elf
->strtab
+ after
->st_name
);
884 warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s\n",
885 modname
, fromsec
, (unsigned long long)r
.r_offset
,
886 secname
, refsymname
);
890 static unsigned int *reloc_location(struct elf_info
*elf
,
891 int rsection
, Elf_Rela
*r
)
893 Elf_Shdr
*sechdrs
= elf
->sechdrs
;
894 int section
= sechdrs
[rsection
].sh_info
;
896 return (void *)elf
->hdr
+ sechdrs
[section
].sh_offset
+
897 (r
->r_offset
- sechdrs
[section
].sh_addr
);
900 static int addend_386_rel(struct elf_info
*elf
, int rsection
, Elf_Rela
*r
)
902 unsigned int r_typ
= ELF_R_TYPE(r
->r_info
);
903 unsigned int *location
= reloc_location(elf
, rsection
, r
);
907 r
->r_addend
= TO_NATIVE(*location
);
910 r
->r_addend
= TO_NATIVE(*location
) + 4;
911 /* For CONFIG_RELOCATABLE=y */
912 if (elf
->hdr
->e_type
== ET_EXEC
)
913 r
->r_addend
+= r
->r_offset
;
919 static int addend_arm_rel(struct elf_info
*elf
, int rsection
, Elf_Rela
*r
)
921 unsigned int r_typ
= ELF_R_TYPE(r
->r_info
);
925 /* From ARM ABI: (S + A) | T */
926 r
->r_addend
= (int)(long)(elf
->symtab_start
+ ELF_R_SYM(r
->r_info
));
929 /* From ARM ABI: ((S + A) | T) - P */
930 r
->r_addend
= (int)(long)(elf
->hdr
+ elf
->sechdrs
[rsection
].sh_offset
+
931 (r
->r_offset
- elf
->sechdrs
[rsection
].sh_addr
));
939 static int addend_mips_rel(struct elf_info
*elf
, int rsection
, Elf_Rela
*r
)
941 unsigned int r_typ
= ELF_R_TYPE(r
->r_info
);
942 unsigned int *location
= reloc_location(elf
, rsection
, r
);
945 if (r_typ
== R_MIPS_HI16
)
946 return 1; /* skip this */
947 inst
= TO_NATIVE(*location
);
950 r
->r_addend
= inst
& 0xffff;
953 r
->r_addend
= (inst
& 0x03ffffff) << 2;
963 * A module includes a number of sections that are discarded
964 * either when loaded or when used as built-in.
965 * For loaded modules all functions marked __init and all data
966 * marked __initdata will be discarded when the module has been intialized.
967 * Likewise for modules used built-in the sections marked __exit
968 * are discarded because __exit marked function are supposed to be called
969 * only when a moduel is unloaded which never happes for built-in modules.
970 * The check_sec_ref() function traverses all relocation records
971 * to find all references to a section that reference a section that will
972 * be discarded and warns about it.
974 static void check_sec_ref(struct module
*mod
, const char *modname
,
975 struct elf_info
*elf
,
976 int section(const char*),
977 int section_ref_ok(const char *))
981 Elf_Ehdr
*hdr
= elf
->hdr
;
982 Elf_Shdr
*sechdrs
= elf
->sechdrs
;
983 const char *secstrings
= (void *)hdr
+
984 sechdrs
[hdr
->e_shstrndx
].sh_offset
;
986 /* Walk through all sections */
987 for (i
= 0; i
< hdr
->e_shnum
; i
++) {
988 const char *name
= secstrings
+ sechdrs
[i
].sh_name
;
992 /* We want to process only relocation sections and not .init */
993 if (sechdrs
[i
].sh_type
== SHT_RELA
) {
995 Elf_Rela
*start
= (void *)hdr
+ sechdrs
[i
].sh_offset
;
996 Elf_Rela
*stop
= (void*)start
+ sechdrs
[i
].sh_size
;
997 name
+= strlen(".rela");
998 if (section_ref_ok(name
))
1001 for (rela
= start
; rela
< stop
; rela
++) {
1002 r
.r_offset
= TO_NATIVE(rela
->r_offset
);
1003 #if KERNEL_ELFCLASS == ELFCLASS64
1004 if (hdr
->e_machine
== EM_MIPS
) {
1006 r_sym
= ELF64_MIPS_R_SYM(rela
->r_info
);
1007 r_sym
= TO_NATIVE(r_sym
);
1008 r_typ
= ELF64_MIPS_R_TYPE(rela
->r_info
);
1009 r
.r_info
= ELF64_R_INFO(r_sym
, r_typ
);
1011 r
.r_info
= TO_NATIVE(rela
->r_info
);
1012 r_sym
= ELF_R_SYM(r
.r_info
);
1015 r
.r_info
= TO_NATIVE(rela
->r_info
);
1016 r_sym
= ELF_R_SYM(r
.r_info
);
1018 r
.r_addend
= TO_NATIVE(rela
->r_addend
);
1019 sym
= elf
->symtab_start
+ r_sym
;
1020 /* Skip special sections */
1021 if (sym
->st_shndx
>= SHN_LORESERVE
)
1024 secname
= secstrings
+
1025 sechdrs
[sym
->st_shndx
].sh_name
;
1026 if (section(secname
))
1027 warn_sec_mismatch(modname
, name
,
1030 } else if (sechdrs
[i
].sh_type
== SHT_REL
) {
1032 Elf_Rel
*start
= (void *)hdr
+ sechdrs
[i
].sh_offset
;
1033 Elf_Rel
*stop
= (void*)start
+ sechdrs
[i
].sh_size
;
1034 name
+= strlen(".rel");
1035 if (section_ref_ok(name
))
1038 for (rel
= start
; rel
< stop
; rel
++) {
1039 r
.r_offset
= TO_NATIVE(rel
->r_offset
);
1040 #if KERNEL_ELFCLASS == ELFCLASS64
1041 if (hdr
->e_machine
== EM_MIPS
) {
1043 r_sym
= ELF64_MIPS_R_SYM(rel
->r_info
);
1044 r_sym
= TO_NATIVE(r_sym
);
1045 r_typ
= ELF64_MIPS_R_TYPE(rel
->r_info
);
1046 r
.r_info
= ELF64_R_INFO(r_sym
, r_typ
);
1048 r
.r_info
= TO_NATIVE(rel
->r_info
);
1049 r_sym
= ELF_R_SYM(r
.r_info
);
1052 r
.r_info
= TO_NATIVE(rel
->r_info
);
1053 r_sym
= ELF_R_SYM(r
.r_info
);
1056 switch (hdr
->e_machine
) {
1058 if (addend_386_rel(elf
, i
, &r
))
1062 if(addend_arm_rel(elf
, i
, &r
))
1066 if (addend_mips_rel(elf
, i
, &r
))
1070 sym
= elf
->symtab_start
+ r_sym
;
1071 /* Skip special sections */
1072 if (sym
->st_shndx
>= SHN_LORESERVE
)
1075 secname
= secstrings
+
1076 sechdrs
[sym
->st_shndx
].sh_name
;
1077 if (section(secname
))
1078 warn_sec_mismatch(modname
, name
,
1086 * Identify sections from which references to either a
1087 * .init or a .exit section is OK.
1089 * [OPD] Keith Ownes <kaos@sgi.com> commented:
1090 * For our future {in}sanity, add a comment that this is the ppc .opd
1091 * section, not the ia64 .opd section.
1092 * ia64 .opd should not point to discarded sections.
1093 * [.rodata] like for .init.text we ignore .rodata references -same reason
1095 static int initexit_section_ref_ok(const char *name
)
1098 /* Absolute section names */
1099 const char *namelist1
[] = {
1100 "__bug_table", /* used by powerpc for BUG() */
1103 ".cranges", /* used by sh64 */
1105 ".machvec", /* ia64 + powerpc uses these */
1107 ".opd", /* See comment [OPD] */
1108 ".parainstructions",
1110 ".plt", /* seen on ARCH=um build on x86_64. Harmless */
1116 /* Start of section names */
1117 const char *namelist2
[] = {
1120 ".note", /* ignore ELF notes - may contain anything */
1121 ".got", /* powerpc - global offset table */
1122 ".toc", /* powerpc - table of contents */
1125 /* part of section name */
1126 const char *namelist3
[] = {
1127 ".unwind", /* Sample: IA_64.unwind.exit.text */
1131 for (s
= namelist1
; *s
; s
++)
1132 if (strcmp(*s
, name
) == 0)
1134 for (s
= namelist2
; *s
; s
++)
1135 if (strncmp(*s
, name
, strlen(*s
)) == 0)
1137 for (s
= namelist3
; *s
; s
++)
1138 if (strstr(name
, *s
) != NULL
)
1145 * Identify sections from which references to a .init section is OK.
1147 * Unfortunately references to read only data that referenced .init
1148 * sections had to be excluded. Almost all of these are false
1149 * positives, they are created by gcc. The downside of excluding rodata
1150 * is that there really are some user references from rodata to
1151 * init code, e.g. drivers/video/vgacon.c:
1153 * const struct consw vga_con = {
1154 * con_startup: vgacon_startup,
1156 * where vgacon_startup is __init. If you want to wade through the false
1157 * positives, take out the check for rodata.
1159 static int init_section_ref_ok(const char *name
)
1162 /* Absolute section names */
1163 const char *namelist1
[] = {
1164 "__dbe_table", /* MIPS generate these */
1165 "__ftr_fixup", /* powerpc cpu feature fixup */
1166 "__fw_ftr_fixup", /* powerpc firmware feature fixup */
1168 ".data.rel.ro", /* used by parisc64 */
1173 /* Start of section names */
1174 const char *namelist2
[] = {
1181 if (initexit_section_ref_ok(name
))
1184 for (s
= namelist1
; *s
; s
++)
1185 if (strcmp(*s
, name
) == 0)
1187 for (s
= namelist2
; *s
; s
++)
1188 if (strncmp(*s
, name
, strlen(*s
)) == 0)
1191 /* If section name ends with ".init" we allow references
1192 * as is the case with .initcallN.init, .early_param.init, .taglist.init etc
1194 if (strrcmp(name
, ".init") == 0)
1200 * Identify sections from which references to a .exit section is OK.
1202 static int exit_section_ref_ok(const char *name
)
1205 /* Absolute section names */
1206 const char *namelist1
[] = {
1214 if (initexit_section_ref_ok(name
))
1217 for (s
= namelist1
; *s
; s
++)
1218 if (strcmp(*s
, name
) == 0)
1223 static void read_symbols(char *modname
)
1225 const char *symname
;
1229 struct elf_info info
= { };
1232 if (!parse_elf(&info
, modname
))
1235 mod
= new_module(modname
);
1237 /* When there's no vmlinux, don't print warnings about
1238 * unresolved symbols (since there'll be too many ;) */
1239 if (is_vmlinux(modname
)) {
1244 license
= get_modinfo(info
.modinfo
, info
.modinfo_len
, "license");
1246 if (license_is_gpl_compatible(license
))
1247 mod
->gpl_compatible
= 1;
1249 mod
->gpl_compatible
= 0;
1252 license
= get_next_modinfo(info
.modinfo
, info
.modinfo_len
,
1253 "license", license
);
1256 for (sym
= info
.symtab_start
; sym
< info
.symtab_stop
; sym
++) {
1257 symname
= info
.strtab
+ sym
->st_name
;
1259 handle_modversions(mod
, &info
, sym
, symname
);
1260 handle_moddevtable(mod
, &info
, sym
, symname
);
1262 if (is_vmlinux(modname
) && vmlinux_section_warnings
) {
1263 check_sec_ref(mod
, modname
, &info
, init_section
, init_section_ref_ok
);
1264 check_sec_ref(mod
, modname
, &info
, exit_section
, exit_section_ref_ok
);
1267 version
= get_modinfo(info
.modinfo
, info
.modinfo_len
, "version");
1269 maybe_frob_rcs_version(modname
, version
, info
.modinfo
,
1270 version
- (char *)info
.hdr
);
1271 if (version
|| (all_versions
&& !is_vmlinux(modname
)))
1272 get_src_version(modname
, mod
->srcversion
,
1273 sizeof(mod
->srcversion
)-1);
1275 parse_elf_finish(&info
);
1277 /* Our trick to get versioning for struct_module - it's
1278 * never passed as an argument to an exported function, so
1279 * the automatic versioning doesn't pick it up, but it's really
1280 * important anyhow */
1282 mod
->unres
= alloc_symbol("struct_module", 0, mod
->unres
);
1287 /* We first write the generated file into memory using the
1288 * following helper, then compare to the file on disk and
1289 * only update the later if anything changed */
1291 void __attribute__((format(printf
, 2, 3))) buf_printf(struct buffer
*buf
,
1292 const char *fmt
, ...)
1299 len
= vsnprintf(tmp
, SZ
, fmt
, ap
);
1300 buf_write(buf
, tmp
, len
);
1304 void buf_write(struct buffer
*buf
, const char *s
, int len
)
1306 if (buf
->size
- buf
->pos
< len
) {
1307 buf
->size
+= len
+ SZ
;
1308 buf
->p
= realloc(buf
->p
, buf
->size
);
1310 strncpy(buf
->p
+ buf
->pos
, s
, len
);
1314 static void check_for_gpl_usage(enum export exp
, const char *m
, const char *s
)
1316 const char *e
= is_vmlinux(m
) ?"":".ko";
1320 fatal("modpost: GPL-incompatible module %s%s "
1321 "uses GPL-only symbol '%s'\n", m
, e
, s
);
1323 case export_unused_gpl
:
1324 fatal("modpost: GPL-incompatible module %s%s "
1325 "uses GPL-only symbol marked UNUSED '%s'\n", m
, e
, s
);
1327 case export_gpl_future
:
1328 warn("modpost: GPL-incompatible module %s%s "
1329 "uses future GPL-only symbol '%s'\n", m
, e
, s
);
1333 case export_unknown
:
1339 static void check_for_unused(enum export exp
, const char* m
, const char* s
)
1341 const char *e
= is_vmlinux(m
) ?"":".ko";
1345 case export_unused_gpl
:
1346 warn("modpost: module %s%s "
1347 "uses symbol '%s' marked UNUSED\n", m
, e
, s
);
1355 static void check_exports(struct module
*mod
)
1357 struct symbol
*s
, *exp
;
1359 for (s
= mod
->unres
; s
; s
= s
->next
) {
1360 const char *basename
;
1361 exp
= find_symbol(s
->name
);
1362 if (!exp
|| exp
->module
== mod
)
1364 basename
= strrchr(mod
->name
, '/');
1368 basename
= mod
->name
;
1369 if (!mod
->gpl_compatible
)
1370 check_for_gpl_usage(exp
->export
, basename
, exp
->name
);
1371 check_for_unused(exp
->export
, basename
, exp
->name
);
1376 * Header for the generated file
1378 static void add_header(struct buffer
*b
, struct module
*mod
)
1380 buf_printf(b
, "#include <linux/module.h>\n");
1381 buf_printf(b
, "#include <linux/vermagic.h>\n");
1382 buf_printf(b
, "#include <linux/compiler.h>\n");
1383 buf_printf(b
, "\n");
1384 buf_printf(b
, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
1385 buf_printf(b
, "\n");
1386 buf_printf(b
, "struct module __this_module\n");
1387 buf_printf(b
, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
1388 buf_printf(b
, " .name = KBUILD_MODNAME,\n");
1390 buf_printf(b
, " .init = init_module,\n");
1391 if (mod
->has_cleanup
)
1392 buf_printf(b
, "#ifdef CONFIG_MODULE_UNLOAD\n"
1393 " .exit = cleanup_module,\n"
1395 buf_printf(b
, " .arch = MODULE_ARCH_INIT,\n");
1396 buf_printf(b
, "};\n");
1400 * Record CRCs for unresolved symbols
1402 static int add_versions(struct buffer
*b
, struct module
*mod
)
1404 struct symbol
*s
, *exp
;
1407 for (s
= mod
->unres
; s
; s
= s
->next
) {
1408 exp
= find_symbol(s
->name
);
1409 if (!exp
|| exp
->module
== mod
) {
1410 if (have_vmlinux
&& !s
->weak
) {
1411 if (warn_unresolved
) {
1412 warn("\"%s\" [%s.ko] undefined!\n",
1413 s
->name
, mod
->name
);
1415 merror("\"%s\" [%s.ko] undefined!\n",
1416 s
->name
, mod
->name
);
1422 s
->module
= exp
->module
;
1423 s
->crc_valid
= exp
->crc_valid
;
1430 buf_printf(b
, "\n");
1431 buf_printf(b
, "static const struct modversion_info ____versions[]\n");
1432 buf_printf(b
, "__attribute_used__\n");
1433 buf_printf(b
, "__attribute__((section(\"__versions\"))) = {\n");
1435 for (s
= mod
->unres
; s
; s
= s
->next
) {
1439 if (!s
->crc_valid
) {
1440 warn("\"%s\" [%s.ko] has no CRC!\n",
1441 s
->name
, mod
->name
);
1444 buf_printf(b
, "\t{ %#8x, \"%s\" },\n", s
->crc
, s
->name
);
1447 buf_printf(b
, "};\n");
1452 static void add_depends(struct buffer
*b
, struct module
*mod
,
1453 struct module
*modules
)
1459 for (m
= modules
; m
; m
= m
->next
) {
1460 m
->seen
= is_vmlinux(m
->name
);
1463 buf_printf(b
, "\n");
1464 buf_printf(b
, "static const char __module_depends[]\n");
1465 buf_printf(b
, "__attribute_used__\n");
1466 buf_printf(b
, "__attribute__((section(\".modinfo\"))) =\n");
1467 buf_printf(b
, "\"depends=");
1468 for (s
= mod
->unres
; s
; s
= s
->next
) {
1473 if (s
->module
->seen
)
1476 s
->module
->seen
= 1;
1477 if ((p
= strrchr(s
->module
->name
, '/')) != NULL
)
1480 p
= s
->module
->name
;
1481 buf_printf(b
, "%s%s", first
? "" : ",", p
);
1484 buf_printf(b
, "\";\n");
1487 static void add_srcversion(struct buffer
*b
, struct module
*mod
)
1489 if (mod
->srcversion
[0]) {
1490 buf_printf(b
, "\n");
1491 buf_printf(b
, "MODULE_INFO(srcversion, \"%s\");\n",
1496 static void write_if_changed(struct buffer
*b
, const char *fname
)
1502 file
= fopen(fname
, "r");
1506 if (fstat(fileno(file
), &st
) < 0)
1509 if (st
.st_size
!= b
->pos
)
1512 tmp
= NOFAIL(malloc(b
->pos
));
1513 if (fread(tmp
, 1, b
->pos
, file
) != b
->pos
)
1516 if (memcmp(tmp
, b
->p
, b
->pos
) != 0)
1528 file
= fopen(fname
, "w");
1533 if (fwrite(b
->p
, 1, b
->pos
, file
) != b
->pos
) {
1540 /* parse Module.symvers file. line format:
1541 * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
1543 static void read_dump(const char *fname
, unsigned int kernel
)
1545 unsigned long size
, pos
= 0;
1546 void *file
= grab_file(fname
, &size
);
1550 /* No symbol versions, silently ignore */
1553 while ((line
= get_next_line(&pos
, file
, size
))) {
1554 char *symname
, *modname
, *d
, *export
, *end
;
1559 if (!(symname
= strchr(line
, '\t')))
1562 if (!(modname
= strchr(symname
, '\t')))
1565 if ((export
= strchr(modname
, '\t')) != NULL
)
1567 if (export
&& ((end
= strchr(export
, '\t')) != NULL
))
1569 crc
= strtoul(line
, &d
, 16);
1570 if (*symname
== '\0' || *modname
== '\0' || *d
!= '\0')
1573 if (!(mod
= find_module(modname
))) {
1574 if (is_vmlinux(modname
)) {
1577 mod
= new_module(NOFAIL(strdup(modname
)));
1580 s
= sym_add_exported(symname
, mod
, export_no(export
));
1583 sym_update_crc(symname
, mod
, crc
, export_no(export
));
1587 fatal("parse error in symbol dump file\n");
1590 /* For normal builds always dump all symbols.
1591 * For external modules only dump symbols
1592 * that are not read from kernel Module.symvers.
1594 static int dump_sym(struct symbol
*sym
)
1596 if (!external_module
)
1598 if (sym
->vmlinux
|| sym
->kernel
)
1603 static void write_dump(const char *fname
)
1605 struct buffer buf
= { };
1606 struct symbol
*symbol
;
1609 for (n
= 0; n
< SYMBOL_HASH_SIZE
; n
++) {
1610 symbol
= symbolhash
[n
];
1612 if (dump_sym(symbol
))
1613 buf_printf(&buf
, "0x%08x\t%s\t%s\t%s\n",
1614 symbol
->crc
, symbol
->name
,
1615 symbol
->module
->name
,
1616 export_str(symbol
->export
));
1617 symbol
= symbol
->next
;
1620 write_if_changed(&buf
, fname
);
1623 int main(int argc
, char **argv
)
1626 struct buffer buf
= { };
1628 char *kernel_read
= NULL
, *module_read
= NULL
;
1629 char *dump_write
= NULL
;
1633 while ((opt
= getopt(argc
, argv
, "i:I:mso:aw")) != -1) {
1636 kernel_read
= optarg
;
1639 module_read
= optarg
;
1640 external_module
= 1;
1646 dump_write
= optarg
;
1652 vmlinux_section_warnings
= 0;
1655 warn_unresolved
= 1;
1663 read_dump(kernel_read
, 1);
1665 read_dump(module_read
, 0);
1667 while (optind
< argc
) {
1668 read_symbols(argv
[optind
++]);
1671 for (mod
= modules
; mod
; mod
= mod
->next
) {
1679 for (mod
= modules
; mod
; mod
= mod
->next
) {
1685 add_header(&buf
, mod
);
1686 err
|= add_versions(&buf
, mod
);
1687 add_depends(&buf
, mod
, modules
);
1688 add_moddevtable(&buf
, mod
);
1689 add_srcversion(&buf
, mod
);
1691 sprintf(fname
, "%s.mod.c", mod
->name
);
1692 write_if_changed(&buf
, fname
);
1696 write_dump(dump_write
);
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