Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge branch 'modversions' (modversions fixes for powerpc from Ard)
Merge kcrctab entry fixes from Ard Biesheuvel:
"This is a followup to [0] 'modversions: redefine kcrctab entries as
relative CRC pointers', but since relative CRC pointers do not work in
modules, and are actually only needed by powerpc with
CONFIG_RELOCATABLE=y, I have made it a Kconfig selectable feature
instead.
First it introduces the MODULE_REL_CRCS Kconfig symbol, and adds the
kbuild handling of it, i.e., modpost, genksyms and kallsyms.
Then it switches all architectures to 32-bit CRC entries in kcrctab,
where all architectures except powerpc with CONFIG_RELOCATABLE=y use
absolute ELF symbol references as before"
[0] http://marc.info/?l=linux-arch&m=148493613415294&w=2
* emailed patches from Ard Biesheuvel:
module: unify absolute krctab definitions for 32-bit and 64-bit
modversions: treat symbol CRCs as 32 bit quantities
kbuild: modversions: add infrastructure for emitting relative CRCs
+93
-62
+1
arch/powerpc/Kconfig
+1
arch/powerpc/Kconfig
···
484
484
bool "Build a relocatable kernel"
485
485
depends on (PPC64 && !COMPILE_TEST) || (FLATMEM && (44x || FSL_BOOKE))
486
486
select NONSTATIC_KERNEL
487
+
select MODULE_REL_CRCS if MODVERSIONS
487
488
help
488
489
This builds a kernel image that is capable of running at the
489
490
location the kernel is loaded at. For ppc32, there is no any
-4
arch/powerpc/include/asm/module.h
-4
arch/powerpc/include/asm/module.h
-8
arch/powerpc/kernel/module_64.c
-8
arch/powerpc/kernel/module_64.c
···
286
286
for (end = (void *)vers + size; vers < end; vers++)
287
287
if (vers->name[0] == '.') {
288
288
memmove(vers->name, vers->name+1, strlen(vers->name));
289
-
#ifdef ARCH_RELOCATES_KCRCTAB
290
-
/* The TOC symbol has no CRC computed. To avoid CRC
291
-
* check failing, we must force it to the expected
292
-
* value (see CRC check in module.c).
293
-
*/
294
-
if (!strcmp(vers->name, "TOC."))
295
-
vers->crc = -(unsigned long)reloc_start;
296
-
#endif
297
289
}
298
290
}
299
291
+6
-5
include/asm-generic/export.h
+6
-5
include/asm-generic/export.h
···
9
9
#ifndef KSYM_ALIGN
10
10
#define KSYM_ALIGN 8
11
11
#endif
12
-
#ifndef KCRC_ALIGN
13
-
#define KCRC_ALIGN 8
14
-
#endif
15
12
#else
16
13
#define __put .long
17
14
#ifndef KSYM_ALIGN
18
15
#define KSYM_ALIGN 4
19
16
#endif
17
+
#endif
20
18
#ifndef KCRC_ALIGN
21
19
#define KCRC_ALIGN 4
22
-
#endif
23
20
#endif
24
21
25
22
#ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX
···
49
52
.section ___kcrctab\sec+\name,"a"
50
53
.balign KCRC_ALIGN
51
54
KSYM(__kcrctab_\name):
52
-
__put KSYM(__crc_\name)
55
+
#if defined(CONFIG_MODULE_REL_CRCS)
56
+
.long KSYM(__crc_\name) - .
57
+
#else
58
+
.long KSYM(__crc_\name)
59
+
#endif
53
60
.weak KSYM(__crc_\name)
54
61
.previous
55
62
#endif
+12
-5
include/linux/export.h
+12
-5
include/linux/export.h
···
43
43
#ifdef CONFIG_MODVERSIONS
44
44
/* Mark the CRC weak since genksyms apparently decides not to
45
45
* generate a checksums for some symbols */
46
+
#if defined(CONFIG_MODULE_REL_CRCS)
46
47
#define __CRC_SYMBOL(sym, sec) \
47
-
extern __visible void *__crc_##sym __attribute__((weak)); \
48
-
static const unsigned long __kcrctab_##sym \
49
-
__used \
50
-
__attribute__((section("___kcrctab" sec "+" #sym), used)) \
51
-
= (unsigned long) &__crc_##sym;
48
+
asm(" .section \"___kcrctab" sec "+" #sym "\", \"a\" \n" \
49
+
" .weak " VMLINUX_SYMBOL_STR(__crc_##sym) " \n" \
50
+
" .long " VMLINUX_SYMBOL_STR(__crc_##sym) " - . \n" \
51
+
" .previous \n");
52
+
#else
53
+
#define __CRC_SYMBOL(sym, sec) \
54
+
asm(" .section \"___kcrctab" sec "+" #sym "\", \"a\" \n" \
55
+
" .weak " VMLINUX_SYMBOL_STR(__crc_##sym) " \n" \
56
+
" .long " VMLINUX_SYMBOL_STR(__crc_##sym) " \n" \
57
+
" .previous \n");
58
+
#endif
52
59
#else
53
60
#define __CRC_SYMBOL(sym, sec)
54
61
#endif
+7
-7
include/linux/module.h
+7
-7
include/linux/module.h
···
346
346
347
347
/* Exported symbols */
348
348
const struct kernel_symbol *syms;
349
-
const unsigned long *crcs;
349
+
const s32 *crcs;
350
350
unsigned int num_syms;
351
351
352
352
/* Kernel parameters. */
···
359
359
/* GPL-only exported symbols. */
360
360
unsigned int num_gpl_syms;
361
361
const struct kernel_symbol *gpl_syms;
362
-
const unsigned long *gpl_crcs;
362
+
const s32 *gpl_crcs;
363
363
364
364
#ifdef CONFIG_UNUSED_SYMBOLS
365
365
/* unused exported symbols. */
366
366
const struct kernel_symbol *unused_syms;
367
-
const unsigned long *unused_crcs;
367
+
const s32 *unused_crcs;
368
368
unsigned int num_unused_syms;
369
369
370
370
/* GPL-only, unused exported symbols. */
371
371
unsigned int num_unused_gpl_syms;
372
372
const struct kernel_symbol *unused_gpl_syms;
373
-
const unsigned long *unused_gpl_crcs;
373
+
const s32 *unused_gpl_crcs;
374
374
#endif
375
375
376
376
#ifdef CONFIG_MODULE_SIG
···
382
382
383
383
/* symbols that will be GPL-only in the near future. */
384
384
const struct kernel_symbol *gpl_future_syms;
385
-
const unsigned long *gpl_future_crcs;
385
+
const s32 *gpl_future_crcs;
386
386
unsigned int num_gpl_future_syms;
387
387
388
388
/* Exception table */
···
523
523
524
524
struct symsearch {
525
525
const struct kernel_symbol *start, *stop;
526
-
const unsigned long *crcs;
526
+
const s32 *crcs;
527
527
enum {
528
528
NOT_GPL_ONLY,
529
529
GPL_ONLY,
···
539
539
*/
540
540
const struct kernel_symbol *find_symbol(const char *name,
541
541
struct module **owner,
542
-
const unsigned long **crc,
542
+
const s32 **crc,
543
543
bool gplok,
544
544
bool warn);
545
545
+4
init/Kconfig
+4
init/Kconfig
+25
-28
kernel/module.c
+25
-28
kernel/module.c
···
389
389
extern const struct kernel_symbol __stop___ksymtab_gpl[];
390
390
extern const struct kernel_symbol __start___ksymtab_gpl_future[];
391
391
extern const struct kernel_symbol __stop___ksymtab_gpl_future[];
392
-
extern const unsigned long __start___kcrctab[];
393
-
extern const unsigned long __start___kcrctab_gpl[];
394
-
extern const unsigned long __start___kcrctab_gpl_future[];
392
+
extern const s32 __start___kcrctab[];
393
+
extern const s32 __start___kcrctab_gpl[];
394
+
extern const s32 __start___kcrctab_gpl_future[];
395
395
#ifdef CONFIG_UNUSED_SYMBOLS
396
396
extern const struct kernel_symbol __start___ksymtab_unused[];
397
397
extern const struct kernel_symbol __stop___ksymtab_unused[];
398
398
extern const struct kernel_symbol __start___ksymtab_unused_gpl[];
399
399
extern const struct kernel_symbol __stop___ksymtab_unused_gpl[];
400
-
extern const unsigned long __start___kcrctab_unused[];
401
-
extern const unsigned long __start___kcrctab_unused_gpl[];
400
+
extern const s32 __start___kcrctab_unused[];
401
+
extern const s32 __start___kcrctab_unused_gpl[];
402
402
#endif
403
403
404
404
#ifndef CONFIG_MODVERSIONS
···
497
497
498
498
/* Output */
499
499
struct module *owner;
500
-
const unsigned long *crc;
500
+
const s32 *crc;
501
501
const struct kernel_symbol *sym;
502
502
};
503
503
···
563
563
* (optional) module which owns it. Needs preempt disabled or module_mutex. */
564
564
const struct kernel_symbol *find_symbol(const char *name,
565
565
struct module **owner,
566
-
const unsigned long **crc,
566
+
const s32 **crc,
567
567
bool gplok,
568
568
bool warn)
569
569
{
···
1249
1249
}
1250
1250
1251
1251
#ifdef CONFIG_MODVERSIONS
1252
-
/* If the arch applies (non-zero) relocations to kernel kcrctab, unapply it. */
1253
-
static unsigned long maybe_relocated(unsigned long crc,
1254
-
const struct module *crc_owner)
1252
+
1253
+
static u32 resolve_rel_crc(const s32 *crc)
1255
1254
{
1256
-
#ifdef ARCH_RELOCATES_KCRCTAB
1257
-
if (crc_owner == NULL)
1258
-
return crc - (unsigned long)reloc_start;
1259
-
#endif
1260
-
return crc;
1255
+
return *(u32 *)((void *)crc + *crc);
1261
1256
}
1262
1257
1263
1258
static int check_version(Elf_Shdr *sechdrs,
1264
1259
unsigned int versindex,
1265
1260
const char *symname,
1266
1261
struct module *mod,
1267
-
const unsigned long *crc,
1268
-
const struct module *crc_owner)
1262
+
const s32 *crc)
1269
1263
{
1270
1264
unsigned int i, num_versions;
1271
1265
struct modversion_info *versions;
···
1277
1283
/ sizeof(struct modversion_info);
1278
1284
1279
1285
for (i = 0; i < num_versions; i++) {
1286
+
u32 crcval;
1287
+
1280
1288
if (strcmp(versions[i].name, symname) != 0)
1281
1289
continue;
1282
1290
1283
-
if (versions[i].crc == maybe_relocated(*crc, crc_owner))
1291
+
if (IS_ENABLED(CONFIG_MODULE_REL_CRCS))
1292
+
crcval = resolve_rel_crc(crc);
1293
+
else
1294
+
crcval = *crc;
1295
+
if (versions[i].crc == crcval)
1284
1296
return 1;
1285
-
pr_debug("Found checksum %lX vs module %lX\n",
1286
-
maybe_relocated(*crc, crc_owner), versions[i].crc);
1297
+
pr_debug("Found checksum %X vs module %lX\n",
1298
+
crcval, versions[i].crc);
1287
1299
goto bad_version;
1288
1300
}
1289
1301
···
1307
1307
unsigned int versindex,
1308
1308
struct module *mod)
1309
1309
{
1310
-
const unsigned long *crc;
1310
+
const s32 *crc;
1311
1311
1312
1312
/*
1313
1313
* Since this should be found in kernel (which can't be removed), no
···
1321
1321
}
1322
1322
preempt_enable();
1323
1323
return check_version(sechdrs, versindex,
1324
-
VMLINUX_SYMBOL_STR(module_layout), mod, crc,
1325
-
NULL);
1324
+
VMLINUX_SYMBOL_STR(module_layout), mod, crc);
1326
1325
}
1327
1326
1328
1327
/* First part is kernel version, which we ignore if module has crcs. */
···
1339
1340
unsigned int versindex,
1340
1341
const char *symname,
1341
1342
struct module *mod,
1342
-
const unsigned long *crc,
1343
-
const struct module *crc_owner)
1343
+
const s32 *crc)
1344
1344
{
1345
1345
return 1;
1346
1346
}
···
1366
1368
{
1367
1369
struct module *owner;
1368
1370
const struct kernel_symbol *sym;
1369
-
const unsigned long *crc;
1371
+
const s32 *crc;
1370
1372
int err;
1371
1373
1372
1374
/*
···
1381
1383
if (!sym)
1382
1384
goto unlock;
1383
1385
1384
-
if (!check_version(info->sechdrs, info->index.vers, name, mod, crc,
1385
-
owner)) {
1386
+
if (!check_version(info->sechdrs, info->index.vers, name, mod, crc)) {
1386
1387
sym = ERR_PTR(-EINVAL);
1387
1388
goto getname;
1388
1389
}
+2
scripts/Makefile.build
+2
scripts/Makefile.build
···
164
164
$(CPP) -D__GENKSYMS__ $(c_flags) $< | \
165
165
$(GENKSYMS) $(if $(1), -T $(2)) \
166
166
$(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX)) \
167
+
$(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \
167
168
$(if $(KBUILD_PRESERVE),-p) \
168
169
-r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
169
170
···
338
337
$(CPP) -D__GENKSYMS__ $(c_flags) -xc - | \
339
338
$(GENKSYMS) $(if $(1), -T $(2)) \
340
339
$(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX)) \
340
+
$(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \
341
341
$(if $(KBUILD_PRESERVE),-p) \
342
342
-r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
343
343
+14
-5
scripts/genksyms/genksyms.c
+14
-5
scripts/genksyms/genksyms.c
···
44
44
int in_source_file;
45
45
46
46
static int flag_debug, flag_dump_defs, flag_reference, flag_dump_types,
47
-
flag_preserve, flag_warnings;
47
+
flag_preserve, flag_warnings, flag_rel_crcs;
48
48
static const char *mod_prefix = "";
49
49
50
50
static int errors;
···
693
693
fputs(">\n", debugfile);
694
694
695
695
/* Used as a linker script. */
696
-
printf("%s__crc_%s = 0x%08lx ;\n", mod_prefix, name, crc);
696
+
printf(!flag_rel_crcs ? "%s__crc_%s = 0x%08lx;\n" :
697
+
"SECTIONS { .rodata : ALIGN(4) { "
698
+
"%s__crc_%s = .; LONG(0x%08lx); } }\n",
699
+
mod_prefix, name, crc);
697
700
}
698
701
}
699
702
···
733
730
734
731
static void genksyms_usage(void)
735
732
{
736
-
fputs("Usage:\n" "genksyms [-adDTwqhV] > /path/to/.tmp_obj.ver\n" "\n"
733
+
fputs("Usage:\n" "genksyms [-adDTwqhVR] > /path/to/.tmp_obj.ver\n" "\n"
737
734
#ifdef __GNU_LIBRARY__
738
735
" -s, --symbol-prefix Select symbol prefix\n"
739
736
" -d, --debug Increment the debug level (repeatable)\n"
···
745
742
" -q, --quiet Disable warnings (default)\n"
746
743
" -h, --help Print this message\n"
747
744
" -V, --version Print the release version\n"
745
+
" -R, --relative-crc Emit section relative symbol CRCs\n"
748
746
#else /* __GNU_LIBRARY__ */
749
747
" -s Select symbol prefix\n"
750
748
" -d Increment the debug level (repeatable)\n"
···
757
753
" -q Disable warnings (default)\n"
758
754
" -h Print this message\n"
759
755
" -V Print the release version\n"
756
+
" -R Emit section relative symbol CRCs\n"
760
757
#endif /* __GNU_LIBRARY__ */
761
758
, stderr);
762
759
}
···
779
774
{"preserve", 0, 0, 'p'},
780
775
{"version", 0, 0, 'V'},
781
776
{"help", 0, 0, 'h'},
777
+
{"relative-crc", 0, 0, 'R'},
782
778
{0, 0, 0, 0}
783
779
};
784
780
785
-
while ((o = getopt_long(argc, argv, "s:dwqVDr:T:ph",
781
+
while ((o = getopt_long(argc, argv, "s:dwqVDr:T:phR",
786
782
&long_opts[0], NULL)) != EOF)
787
783
#else /* __GNU_LIBRARY__ */
788
-
while ((o = getopt(argc, argv, "s:dwqVDr:T:ph")) != EOF)
784
+
while ((o = getopt(argc, argv, "s:dwqVDr:T:phR")) != EOF)
789
785
#endif /* __GNU_LIBRARY__ */
790
786
switch (o) {
791
787
case 's':
···
829
823
case 'h':
830
824
genksyms_usage();
831
825
return 0;
826
+
case 'R':
827
+
flag_rel_crcs = 1;
828
+
break;
832
829
default:
833
830
genksyms_usage();
834
831
return 1;
+12
scripts/kallsyms.c
+12
scripts/kallsyms.c
···
219
219
"_SDA2_BASE_", /* ppc */
220
220
NULL };
221
221
222
+
static char *special_prefixes[] = {
223
+
"__crc_", /* modversions */
224
+
NULL };
225
+
222
226
static char *special_suffixes[] = {
223
227
"_veneer", /* arm */
224
228
"_from_arm", /* arm */
···
262
258
for (i = 0; special_symbols[i]; i++)
263
259
if (strcmp(sym_name, special_symbols[i]) == 0)
264
260
return 0;
261
+
262
+
for (i = 0; special_prefixes[i]; i++) {
263
+
int l = strlen(special_prefixes[i]);
264
+
265
+
if (l <= strlen(sym_name) &&
266
+
strncmp(sym_name, special_prefixes[i], l) == 0)
267
+
return 0;
268
+
}
265
269
266
270
for (i = 0; special_suffixes[i]; i++) {
267
271
int l = strlen(sym_name) - strlen(special_suffixes[i]);
+10
scripts/mod/modpost.c
+10
scripts/mod/modpost.c
···
621
621
if (strncmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
622
622
is_crc = true;
623
623
crc = (unsigned int) sym->st_value;
624
+
if (sym->st_shndx != SHN_UNDEF && sym->st_shndx != SHN_ABS) {
625
+
unsigned int *crcp;
626
+
627
+
/* symbol points to the CRC in the ELF object */
628
+
crcp = (void *)info->hdr + sym->st_value +
629
+
info->sechdrs[sym->st_shndx].sh_offset -
630
+
(info->hdr->e_type != ET_REL ?
631
+
info->sechdrs[sym->st_shndx].sh_addr : 0);
632
+
crc = *crcp;
633
+
}
624
634
sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
625
635
export);
626
636
}