* [PATCH v5 1/3] kbuild: modversions: add infrastructure for emitting relative CRCs
2017-02-03 9:54 [PATCH v5 0/3] modversions: redefine kcrctab entries as 32-bit values Ard Biesheuvel
@ 2017-02-03 9:54 ` Ard Biesheuvel
2017-02-03 9:54 ` [PATCH v5 2/3] modversions: treat symbol CRCs as 32 bit quantities Ard Biesheuvel
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Ard Biesheuvel @ 2017-02-03 9:54 UTC (permalink / raw)
To: linux-kbuild, linux-arch, linux-kernel, linuxppc-dev, jeyu,
rusty, mmarek, mpe
Cc: torvalds, arnd, viro, linux-arm-kernel, Ard Biesheuvel
This add the kbuild infrastructure that will allow architectures to emit
vmlinux symbol CRCs as 32-bit offsets to another location in the kernel
where the actual value is stored. This works around problems with CRCs
being mistaken for relocatable symbols on kernels that self relocate at
runtime (i.e., powerpc with CONFIG_RELOCATABLE=y)
For the kbuild side of things, this comes down to the following:
- introducing a Kconfig symbol MODULE_REL_CRCS
- adding a -R switch to genksyms to instruct it to emit the CRC symbols
as references into the .rodata section
- making modpost distinguish such references from absolute CRC symbols by
the section index (SHN_ABS)
- making kallsyms disregard non-absolute symbols with a __crc_ prefix
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
init/Kconfig | 4 ++++
scripts/Makefile.build | 2 ++
scripts/genksyms/genksyms.c | 19 ++++++++++++++-----
scripts/kallsyms.c | 12 ++++++++++++
scripts/mod/modpost.c | 10 ++++++++++
5 files changed, 42 insertions(+), 5 deletions(-)
diff --git a/init/Kconfig b/init/Kconfig
index e1a937348a3e..4dd8bd232a1d 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1987,6 +1987,10 @@ config MODVERSIONS
make them incompatible with the kernel you are running. If
unsure, say N.
+config MODULE_REL_CRCS
+ bool
+ depends on MODVERSIONS
+
config MODULE_SRCVERSION_ALL
bool "Source checksum for all modules"
help
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index eadcd4d359d9..d883116ebaa4 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -164,6 +164,7 @@ cmd_gensymtypes_c = \
$(CPP) -D__GENKSYMS__ $(c_flags) $< | \
$(GENKSYMS) $(if $(1), -T $(2)) \
$(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX)) \
+ $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \
$(if $(KBUILD_PRESERVE),-p) \
-r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
@@ -337,6 +338,7 @@ cmd_gensymtypes_S = \
$(CPP) -D__GENKSYMS__ $(c_flags) -xc - | \
$(GENKSYMS) $(if $(1), -T $(2)) \
$(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX)) \
+ $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \
$(if $(KBUILD_PRESERVE),-p) \
-r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
diff --git a/scripts/genksyms/genksyms.c b/scripts/genksyms/genksyms.c
index 06121ce524a7..c9235d8340f1 100644
--- a/scripts/genksyms/genksyms.c
+++ b/scripts/genksyms/genksyms.c
@@ -44,7 +44,7 @@ char *cur_filename, *source_file;
int in_source_file;
static int flag_debug, flag_dump_defs, flag_reference, flag_dump_types,
- flag_preserve, flag_warnings;
+ flag_preserve, flag_warnings, flag_rel_crcs;
static const char *mod_prefix = "";
static int errors;
@@ -693,7 +693,10 @@ void export_symbol(const char *name)
fputs(">\n", debugfile);
/* Used as a linker script. */
- printf("%s__crc_%s = 0x%08lx ;\n", mod_prefix, name, crc);
+ printf(!flag_rel_crcs ? "%s__crc_%s = 0x%08lx;\n" :
+ "SECTIONS { .rodata : ALIGN(4) { "
+ "%s__crc_%s = .; LONG(0x%08lx); } }\n",
+ mod_prefix, name, crc);
}
}
@@ -730,7 +733,7 @@ void error_with_pos(const char *fmt, ...)
static void genksyms_usage(void)
{
- fputs("Usage:\n" "genksyms [-adDTwqhV] > /path/to/.tmp_obj.ver\n" "\n"
+ fputs("Usage:\n" "genksyms [-adDTwqhVR] > /path/to/.tmp_obj.ver\n" "\n"
#ifdef __GNU_LIBRARY__
" -s, --symbol-prefix Select symbol prefix\n"
" -d, --debug Increment the debug level (repeatable)\n"
@@ -742,6 +745,7 @@ static void genksyms_usage(void)
" -q, --quiet Disable warnings (default)\n"
" -h, --help Print this message\n"
" -V, --version Print the release version\n"
+ " -R, --relative-crc Emit section relative symbol CRCs\n"
#else /* __GNU_LIBRARY__ */
" -s Select symbol prefix\n"
" -d Increment the debug level (repeatable)\n"
@@ -753,6 +757,7 @@ static void genksyms_usage(void)
" -q Disable warnings (default)\n"
" -h Print this message\n"
" -V Print the release version\n"
+ " -R Emit section relative symbol CRCs\n"
#endif /* __GNU_LIBRARY__ */
, stderr);
}
@@ -774,13 +779,14 @@ int main(int argc, char **argv)
{"preserve", 0, 0, 'p'},
{"version", 0, 0, 'V'},
{"help", 0, 0, 'h'},
+ {"relative-crc", 0, 0, 'R'},
{0, 0, 0, 0}
};
- while ((o = getopt_long(argc, argv, "s:dwqVDr:T:ph",
+ while ((o = getopt_long(argc, argv, "s:dwqVDr:T:phR",
&long_opts[0], NULL)) != EOF)
#else /* __GNU_LIBRARY__ */
- while ((o = getopt(argc, argv, "s:dwqVDr:T:ph")) != EOF)
+ while ((o = getopt(argc, argv, "s:dwqVDr:T:phR")) != EOF)
#endif /* __GNU_LIBRARY__ */
switch (o) {
case 's':
@@ -823,6 +829,9 @@ int main(int argc, char **argv)
case 'h':
genksyms_usage();
return 0;
+ case 'R':
+ flag_rel_crcs = 1;
+ break;
default:
genksyms_usage();
return 1;
diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
index 299b92ca1ae0..5d554419170b 100644
--- a/scripts/kallsyms.c
+++ b/scripts/kallsyms.c
@@ -219,6 +219,10 @@ static int symbol_valid(struct sym_entry *s)
"_SDA2_BASE_", /* ppc */
NULL };
+ static char *special_prefixes[] = {
+ "__crc_", /* modversions */
+ NULL };
+
static char *special_suffixes[] = {
"_veneer", /* arm */
"_from_arm", /* arm */
@@ -259,6 +263,14 @@ static int symbol_valid(struct sym_entry *s)
if (strcmp(sym_name, special_symbols[i]) == 0)
return 0;
+ for (i = 0; special_prefixes[i]; i++) {
+ int l = strlen(special_prefixes[i]);
+
+ if (l <= strlen(sym_name) &&
+ strncmp(sym_name, special_prefixes[i], l) == 0)
+ return 0;
+ }
+
for (i = 0; special_suffixes[i]; i++) {
int l = strlen(sym_name) - strlen(special_suffixes[i]);
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 29c89a6bad3d..4dedd0d3d3a7 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -621,6 +621,16 @@ static void handle_modversions(struct module *mod, struct elf_info *info,
if (strncmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
is_crc = true;
crc = (unsigned int) sym->st_value;
+ if (sym->st_shndx != SHN_UNDEF && sym->st_shndx != SHN_ABS) {
+ unsigned int *crcp;
+
+ /* symbol points to the CRC in the ELF object */
+ crcp = (void *)info->hdr + sym->st_value +
+ info->sechdrs[sym->st_shndx].sh_offset -
+ (info->hdr->e_type != ET_REL ?
+ info->sechdrs[sym->st_shndx].sh_addr : 0);
+ crc = *crcp;
+ }
sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
export);
}
--
2.7.4
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH v5 2/3] modversions: treat symbol CRCs as 32 bit quantities
2017-02-03 9:54 [PATCH v5 0/3] modversions: redefine kcrctab entries as 32-bit values Ard Biesheuvel
2017-02-03 9:54 ` [PATCH v5 1/3] kbuild: modversions: add infrastructure for emitting relative CRCs Ard Biesheuvel
@ 2017-02-03 9:54 ` Ard Biesheuvel
2017-02-03 9:54 ` [PATCH v5 3/3] module: unify absolute krctab definitions for 32-bit and 64-bit Ard Biesheuvel
2017-02-03 16:30 ` [PATCH v5 0/3] modversions: redefine kcrctab entries as 32-bit values Linus Torvalds
3 siblings, 0 replies; 5+ messages in thread
From: Ard Biesheuvel @ 2017-02-03 9:54 UTC (permalink / raw)
To: linux-kbuild, linux-arch, linux-kernel, linuxppc-dev, jeyu,
rusty, mmarek, mpe
Cc: torvalds, arnd, viro, linux-arm-kernel, Ard Biesheuvel
The modversion symbol CRCs are emitted as ELF symbols, which allows us to
easily populate the kcrctab sections by relying on the linker to associate
each kcrctab slot with the correct value.
This has a couple of downsides:
- Given that the CRCs are treated as memory addresses, we waste 4 bytes
for each CRC on 64 bit architectures,
- On architectures that support runtime relocation, a R_<arch>_RELATIVE
relocation entry is emitted for each CRC value, which identifies it as
a quantity that requires fixing up based on the actual runtime load
offset of the kernel. This results in corrupted CRCs unless we
explicitly undo the fixup (and this is currently being handled in the
core module code)
- Such runtime relocation entries take up 24 bytes of __init space each,
resulting in a x8 overhead in [uncompressed] kernel size for CRCs.
Switching to explicit 32 bit values on 64 bit architectures fixes most
of these issues, given that 32 bit values are not treated as quantities
that require fixing up based on the actual runtime load offset. Note that
on some ELF64 architectures [such as PPC64], these 32-bit values are still
emitted as [absolute] runtime relocatable quantities, even if the value
resolves to a build time constant. Since relative relocations are always
resolved at build time, this patch enables MODULE_REL_CRCS on powerpc when
CONFIG_RELOCATABLE=y, which turns the absolute CRC references into relative
references into .rodata where the actual CRC value is stored.
So redefine all CRC fields and variables as u32, and redefine the
__CRC_SYMBOL() macro for 64 bit builds to emit the CRC reference using
inline assembler (which is necessary since 64-bit C code cannot use
32-bit types to hold memory addresses, even if they are ultimately
resolved using values that do not exceed 0xffffffff). To avoid potential
problems with legacy 32-bit architectures using legacy toolchains, the
equivalent C definition of the kcrctab entry is retained for 32-bit
architectures.
Note that this mostly reverts commit d4703aefdbc8 ("module: handle ppc64
relocating kcrctabs when CONFIG_RELOCATABLE=y")
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
arch/powerpc/Kconfig | 1 +
arch/powerpc/include/asm/module.h | 4 --
arch/powerpc/kernel/module_64.c | 8 ---
include/asm-generic/export.h | 11 ++--
include/linux/export.h | 14 ++++++
include/linux/module.h | 14 +++---
kernel/module.c | 53 +++++++++-----------
7 files changed, 53 insertions(+), 52 deletions(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index a8ee573fe610..db8a1ef6bfaf 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -484,6 +484,7 @@ config RELOCATABLE
bool "Build a relocatable kernel"
depends on (PPC64 && !COMPILE_TEST) || (FLATMEM && (44x || FSL_BOOKE))
select NONSTATIC_KERNEL
+ select MODULE_REL_CRCS if MODVERSIONS
help
This builds a kernel image that is capable of running at the
location the kernel is loaded at. For ppc32, there is no any
diff --git a/arch/powerpc/include/asm/module.h b/arch/powerpc/include/asm/module.h
index cc12c61ef315..53885512b8d3 100644
--- a/arch/powerpc/include/asm/module.h
+++ b/arch/powerpc/include/asm/module.h
@@ -90,9 +90,5 @@ static inline int module_finalize_ftrace(struct module *mod, const Elf_Shdr *sec
}
#endif
-#if defined(CONFIG_MODVERSIONS) && defined(CONFIG_PPC64)
-#define ARCH_RELOCATES_KCRCTAB
-#define reloc_start PHYSICAL_START
-#endif
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_MODULE_H */
diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c
index bb1807184bad..0b0f89685b67 100644
--- a/arch/powerpc/kernel/module_64.c
+++ b/arch/powerpc/kernel/module_64.c
@@ -286,14 +286,6 @@ static void dedotify_versions(struct modversion_info *vers,
for (end = (void *)vers + size; vers < end; vers++)
if (vers->name[0] == '.') {
memmove(vers->name, vers->name+1, strlen(vers->name));
-#ifdef ARCH_RELOCATES_KCRCTAB
- /* The TOC symbol has no CRC computed. To avoid CRC
- * check failing, we must force it to the expected
- * value (see CRC check in module.c).
- */
- if (!strcmp(vers->name, "TOC."))
- vers->crc = -(unsigned long)reloc_start;
-#endif
}
}
diff --git a/include/asm-generic/export.h b/include/asm-generic/export.h
index 63554e9f6e0c..719db1968d81 100644
--- a/include/asm-generic/export.h
+++ b/include/asm-generic/export.h
@@ -9,18 +9,15 @@
#ifndef KSYM_ALIGN
#define KSYM_ALIGN 8
#endif
-#ifndef KCRC_ALIGN
-#define KCRC_ALIGN 8
-#endif
#else
#define __put .long
#ifndef KSYM_ALIGN
#define KSYM_ALIGN 4
#endif
+#endif
#ifndef KCRC_ALIGN
#define KCRC_ALIGN 4
#endif
-#endif
#ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX
#define KSYM(name) _##name
@@ -52,7 +49,11 @@ KSYM(__kstrtab_\name):
.section ___kcrctab\sec+\name,"a"
.balign KCRC_ALIGN
KSYM(__kcrctab_\name):
- __put KSYM(__crc_\name)
+#if defined(CONFIG_MODULE_REL_CRCS)
+ .long KSYM(__crc_\name) - .
+#else
+ .long KSYM(__crc_\name)
+#endif
.weak KSYM(__crc_\name)
.previous
#endif
diff --git a/include/linux/export.h b/include/linux/export.h
index 2a0f61fbc731..7473fba6a60c 100644
--- a/include/linux/export.h
+++ b/include/linux/export.h
@@ -43,6 +43,13 @@ extern struct module __this_module;
#ifdef CONFIG_MODVERSIONS
/* Mark the CRC weak since genksyms apparently decides not to
* generate a checksums for some symbols */
+#if defined(CONFIG_MODULE_REL_CRCS)
+#define __CRC_SYMBOL(sym, sec) \
+ asm(" .section \"___kcrctab" sec "+" #sym "\", \"a\" \n" \
+ " .weak " VMLINUX_SYMBOL_STR(__crc_##sym) " \n" \
+ " .long " VMLINUX_SYMBOL_STR(__crc_##sym) " - . \n" \
+ " .previous \n");
+#elif !defined(CONFIG_64BIT)
#define __CRC_SYMBOL(sym, sec) \
extern __visible void *__crc_##sym __attribute__((weak)); \
static const unsigned long __kcrctab_##sym \
@@ -50,6 +57,13 @@ extern struct module __this_module;
__attribute__((section("___kcrctab" sec "+" #sym), used)) \
= (unsigned long) &__crc_##sym;
#else
+#define __CRC_SYMBOL(sym, sec) \
+ asm(" .section \"___kcrctab" sec "+" #sym "\", \"a\" \n" \
+ " .weak " VMLINUX_SYMBOL_STR(__crc_##sym) " \n" \
+ " .long " VMLINUX_SYMBOL_STR(__crc_##sym) " \n" \
+ " .previous \n");
+#endif
+#else
#define __CRC_SYMBOL(sym, sec)
#endif
diff --git a/include/linux/module.h b/include/linux/module.h
index 7c84273d60b9..cc7cba219b20 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -346,7 +346,7 @@ struct module {
/* Exported symbols */
const struct kernel_symbol *syms;
- const unsigned long *crcs;
+ const s32 *crcs;
unsigned int num_syms;
/* Kernel parameters. */
@@ -359,18 +359,18 @@ struct module {
/* GPL-only exported symbols. */
unsigned int num_gpl_syms;
const struct kernel_symbol *gpl_syms;
- const unsigned long *gpl_crcs;
+ const s32 *gpl_crcs;
#ifdef CONFIG_UNUSED_SYMBOLS
/* unused exported symbols. */
const struct kernel_symbol *unused_syms;
- const unsigned long *unused_crcs;
+ const s32 *unused_crcs;
unsigned int num_unused_syms;
/* GPL-only, unused exported symbols. */
unsigned int num_unused_gpl_syms;
const struct kernel_symbol *unused_gpl_syms;
- const unsigned long *unused_gpl_crcs;
+ const s32 *unused_gpl_crcs;
#endif
#ifdef CONFIG_MODULE_SIG
@@ -382,7 +382,7 @@ struct module {
/* symbols that will be GPL-only in the near future. */
const struct kernel_symbol *gpl_future_syms;
- const unsigned long *gpl_future_crcs;
+ const s32 *gpl_future_crcs;
unsigned int num_gpl_future_syms;
/* Exception table */
@@ -523,7 +523,7 @@ struct module *find_module(const char *name);
struct symsearch {
const struct kernel_symbol *start, *stop;
- const unsigned long *crcs;
+ const s32 *crcs;
enum {
NOT_GPL_ONLY,
GPL_ONLY,
@@ -539,7 +539,7 @@ struct symsearch {
*/
const struct kernel_symbol *find_symbol(const char *name,
struct module **owner,
- const unsigned long **crc,
+ const s32 **crc,
bool gplok,
bool warn);
diff --git a/kernel/module.c b/kernel/module.c
index 5088784c0cf9..9f9e31f015ba 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -389,16 +389,16 @@ extern const struct kernel_symbol __start___ksymtab_gpl[];
extern const struct kernel_symbol __stop___ksymtab_gpl[];
extern const struct kernel_symbol __start___ksymtab_gpl_future[];
extern const struct kernel_symbol __stop___ksymtab_gpl_future[];
-extern const unsigned long __start___kcrctab[];
-extern const unsigned long __start___kcrctab_gpl[];
-extern const unsigned long __start___kcrctab_gpl_future[];
+extern const s32 __start___kcrctab[];
+extern const s32 __start___kcrctab_gpl[];
+extern const s32 __start___kcrctab_gpl_future[];
#ifdef CONFIG_UNUSED_SYMBOLS
extern const struct kernel_symbol __start___ksymtab_unused[];
extern const struct kernel_symbol __stop___ksymtab_unused[];
extern const struct kernel_symbol __start___ksymtab_unused_gpl[];
extern const struct kernel_symbol __stop___ksymtab_unused_gpl[];
-extern const unsigned long __start___kcrctab_unused[];
-extern const unsigned long __start___kcrctab_unused_gpl[];
+extern const s32 __start___kcrctab_unused[];
+extern const s32 __start___kcrctab_unused_gpl[];
#endif
#ifndef CONFIG_MODVERSIONS
@@ -497,7 +497,7 @@ struct find_symbol_arg {
/* Output */
struct module *owner;
- const unsigned long *crc;
+ const s32 *crc;
const struct kernel_symbol *sym;
};
@@ -563,7 +563,7 @@ static bool find_symbol_in_section(const struct symsearch *syms,
* (optional) module which owns it. Needs preempt disabled or module_mutex. */
const struct kernel_symbol *find_symbol(const char *name,
struct module **owner,
- const unsigned long **crc,
+ const s32 **crc,
bool gplok,
bool warn)
{
@@ -1249,23 +1249,17 @@ static int try_to_force_load(struct module *mod, const char *reason)
}
#ifdef CONFIG_MODVERSIONS
-/* If the arch applies (non-zero) relocations to kernel kcrctab, unapply it. */
-static unsigned long maybe_relocated(unsigned long crc,
- const struct module *crc_owner)
+
+static u32 resolve_rel_crc(const s32 *crc)
{
-#ifdef ARCH_RELOCATES_KCRCTAB
- if (crc_owner == NULL)
- return crc - (unsigned long)reloc_start;
-#endif
- return crc;
+ return *(u32 *)((void *)crc + *crc);
}
static int check_version(Elf_Shdr *sechdrs,
unsigned int versindex,
const char *symname,
struct module *mod,
- const unsigned long *crc,
- const struct module *crc_owner)
+ const s32 *crc)
{
unsigned int i, num_versions;
struct modversion_info *versions;
@@ -1283,13 +1277,19 @@ static int check_version(Elf_Shdr *sechdrs,
/ sizeof(struct modversion_info);
for (i = 0; i < num_versions; i++) {
+ u32 crcval;
+
if (strcmp(versions[i].name, symname) != 0)
continue;
- if (versions[i].crc == maybe_relocated(*crc, crc_owner))
+ if (IS_ENABLED(CONFIG_MODULE_REL_CRCS))
+ crcval = resolve_rel_crc(crc);
+ else
+ crcval = *crc;
+ if (versions[i].crc == crcval)
return 1;
- pr_debug("Found checksum %lX vs module %lX\n",
- maybe_relocated(*crc, crc_owner), versions[i].crc);
+ pr_debug("Found checksum %X vs module %lX\n",
+ crcval, versions[i].crc);
goto bad_version;
}
@@ -1307,7 +1307,7 @@ static inline int check_modstruct_version(Elf_Shdr *sechdrs,
unsigned int versindex,
struct module *mod)
{
- const unsigned long *crc;
+ const s32 *crc;
/*
* Since this should be found in kernel (which can't be removed), no
@@ -1321,8 +1321,7 @@ static inline int check_modstruct_version(Elf_Shdr *sechdrs,
}
preempt_enable();
return check_version(sechdrs, versindex,
- VMLINUX_SYMBOL_STR(module_layout), mod, crc,
- NULL);
+ VMLINUX_SYMBOL_STR(module_layout), mod, crc);
}
/* First part is kernel version, which we ignore if module has crcs. */
@@ -1340,8 +1339,7 @@ static inline int check_version(Elf_Shdr *sechdrs,
unsigned int versindex,
const char *symname,
struct module *mod,
- const unsigned long *crc,
- const struct module *crc_owner)
+ const s32 *crc)
{
return 1;
}
@@ -1368,7 +1366,7 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
{
struct module *owner;
const struct kernel_symbol *sym;
- const unsigned long *crc;
+ const s32 *crc;
int err;
/*
@@ -1383,8 +1381,7 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
if (!sym)
goto unlock;
- if (!check_version(info->sechdrs, info->index.vers, name, mod, crc,
- owner)) {
+ if (!check_version(info->sechdrs, info->index.vers, name, mod, crc)) {
sym = ERR_PTR(-EINVAL);
goto getname;
}
--
2.7.4
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH v5 3/3] module: unify absolute krctab definitions for 32-bit and 64-bit
2017-02-03 9:54 [PATCH v5 0/3] modversions: redefine kcrctab entries as 32-bit values Ard Biesheuvel
2017-02-03 9:54 ` [PATCH v5 1/3] kbuild: modversions: add infrastructure for emitting relative CRCs Ard Biesheuvel
2017-02-03 9:54 ` [PATCH v5 2/3] modversions: treat symbol CRCs as 32 bit quantities Ard Biesheuvel
@ 2017-02-03 9:54 ` Ard Biesheuvel
2017-02-03 16:30 ` [PATCH v5 0/3] modversions: redefine kcrctab entries as 32-bit values Linus Torvalds
3 siblings, 0 replies; 5+ messages in thread
From: Ard Biesheuvel @ 2017-02-03 9:54 UTC (permalink / raw)
To: linux-kbuild, linux-arch, linux-kernel, linuxppc-dev, jeyu,
rusty, mmarek, mpe
Cc: torvalds, arnd, viro, linux-arm-kernel, Ard Biesheuvel
The previous patch introduced a separate inline asm version of the
krcrctab declaration template for use with 64-bit architectures, which
cannot refer to ELF symbols using 32-bit quantities. This declaration
should be equivalent to the C one for 32-bit architectures, but this
needs to be checked first, so unify them in a separate patch.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
... which can simply be dropped if it turns out to break anything.
include/linux/export.h | 7 -------
1 file changed, 7 deletions(-)
diff --git a/include/linux/export.h b/include/linux/export.h
index 7473fba6a60c..1a1dfdb2a5c6 100644
--- a/include/linux/export.h
+++ b/include/linux/export.h
@@ -49,13 +49,6 @@ extern struct module __this_module;
" .weak " VMLINUX_SYMBOL_STR(__crc_##sym) " \n" \
" .long " VMLINUX_SYMBOL_STR(__crc_##sym) " - . \n" \
" .previous \n");
-#elif !defined(CONFIG_64BIT)
-#define __CRC_SYMBOL(sym, sec) \
- extern __visible void *__crc_##sym __attribute__((weak)); \
- static const unsigned long __kcrctab_##sym \
- __used \
- __attribute__((section("___kcrctab" sec "+" #sym), used)) \
- = (unsigned long) &__crc_##sym;
#else
#define __CRC_SYMBOL(sym, sec) \
asm(" .section \"___kcrctab" sec "+" #sym "\", \"a\" \n" \
--
2.7.4
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH v5 0/3] modversions: redefine kcrctab entries as 32-bit values
2017-02-03 9:54 [PATCH v5 0/3] modversions: redefine kcrctab entries as 32-bit values Ard Biesheuvel
` (2 preceding siblings ...)
2017-02-03 9:54 ` [PATCH v5 3/3] module: unify absolute krctab definitions for 32-bit and 64-bit Ard Biesheuvel
@ 2017-02-03 16:30 ` Linus Torvalds
3 siblings, 0 replies; 5+ messages in thread
From: Linus Torvalds @ 2017-02-03 16:30 UTC (permalink / raw)
To: Ard Biesheuvel
Cc: Linux Kbuild mailing list, linux-arch, Linux Kernel Mailing List,
ppc-dev, Jessica Yu, Rusty Russell, Michal Marek,
Michael Ellerman, Arnd Bergmann, Al Viro, linux-arm-kernel
On Fri, Feb 3, 2017 at 1:54 AM, Ard Biesheuvel
<ard.biesheuvel@linaro.org> wrote:
> This v4 is a followup to [0] 'modversions: redefine kcrctab entries as
> relative CRC pointers' [...]
ok, I have this in a local branch now, assuming it passes my
(admittedly fairly superficial) testing I'll merge it so that we can
put this whole sorry saga behind us.
Thanks,
Linus
^ permalink raw reply [flat|nested] 5+ messages in thread