[PATCH v4 2/2] mips: Differentiate between 32 and 64 bit ELF header

From: Daniel Wagner
Date: Wed Feb 10 2016 - 04:22:47 EST


Depending on the configuration either the 32 or 64 bit version of
elf_check_arch() is defined. parse_crash_elf{32|64}_headers() does
some basic verification of the ELF header via
vmcore_elf{32|64}_check_arch() which happen to map to elf_check_arch().
Since the implementation 32 and 64 bit version of elf_check_arch()
differ, we use the wrong type:

In file included from include/linux/elf.h:4:0,
from fs/proc/vmcore.c:13:
fs/proc/vmcore.c: In function 'parse_crash_elf64_headers':
>> arch/mips/include/asm/elf.h:228:23: error: initialization from incompatible pointer type [-Werror=incompatible-pointer-types]
struct elfhdr *__h = (hdr); \
^
include/linux/crash_dump.h:41:37: note: in expansion of macro 'elf_check_arch'
#define vmcore_elf64_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x))
^
fs/proc/vmcore.c:1015:4: note: in expansion of macro 'vmcore_elf64_check_arch'
!vmcore_elf64_check_arch(&ehdr) ||
^

Therefore, we rather define vmcore_elf{32|64}_check_arch() as a
basic machine check and use it also in binfm_elf?32.c as well.

Signed-off-by: Daniel Wagner <daniel.wagner@xxxxxxxxxxxx>
Suggested-by: Maciej W. Rozycki <macro@xxxxxxxxxx>
Reviewed-by: Maciej W. Rozycki <macro@xxxxxxxxxx>
Reported-by: Fengguang Wu <fengguang.wu@xxxxxxxxx>
---
arch/mips/include/asm/elf.h | 9 +++++++--
arch/mips/kernel/binfmt_elfn32.c | 2 +-
arch/mips/kernel/binfmt_elfo32.c | 2 +-
3 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/arch/mips/include/asm/elf.h b/arch/mips/include/asm/elf.h
index cefb7a5..e090fc3 100644
--- a/arch/mips/include/asm/elf.h
+++ b/arch/mips/include/asm/elf.h
@@ -227,7 +227,7 @@ struct mips_elf_abiflags_v0 {
int __res = 1; \
struct elfhdr *__h = (hdr); \
\
- if (__h->e_machine != EM_MIPS) \
+ if (!mips_elf_check_machine(__h)) \
__res = 0; \
if (__h->e_ident[EI_CLASS] != ELFCLASS32) \
__res = 0; \
@@ -258,7 +258,7 @@ struct mips_elf_abiflags_v0 {
int __res = 1; \
struct elfhdr *__h = (hdr); \
\
- if (__h->e_machine != EM_MIPS) \
+ if (!mips_elf_check_machine(__h)) \
__res = 0; \
if (__h->e_ident[EI_CLASS] != ELFCLASS64) \
__res = 0; \
@@ -285,6 +285,11 @@ struct mips_elf_abiflags_v0 {

#endif /* !defined(ELF_ARCH) */

+#define mips_elf_check_machine(x) ((x)->e_machine == EM_MIPS)
+
+#define vmcore_elf32_check_arch mips_elf_check_machine
+#define vmcore_elf64_check_arch mips_elf_check_machine
+
struct mips_abi;

extern struct mips_abi mips_abi;
diff --git a/arch/mips/kernel/binfmt_elfn32.c b/arch/mips/kernel/binfmt_elfn32.c
index 1188e00..1b992c6 100644
--- a/arch/mips/kernel/binfmt_elfn32.c
+++ b/arch/mips/kernel/binfmt_elfn32.c
@@ -35,7 +35,7 @@ typedef elf_fpreg_t elf_fpregset_t[ELF_NFPREG];
int __res = 1; \
struct elfhdr *__h = (hdr); \
\
- if (__h->e_machine != EM_MIPS) \
+ if (!mips_elf_check_machine(__h)) \
__res = 0; \
if (__h->e_ident[EI_CLASS] != ELFCLASS32) \
__res = 0; \
diff --git a/arch/mips/kernel/binfmt_elfo32.c b/arch/mips/kernel/binfmt_elfo32.c
index 9287678..abd3aff 100644
--- a/arch/mips/kernel/binfmt_elfo32.c
+++ b/arch/mips/kernel/binfmt_elfo32.c
@@ -47,7 +47,7 @@ typedef elf_fpreg_t elf_fpregset_t[ELF_NFPREG];
int __res = 1; \
struct elfhdr *__h = (hdr); \
\
- if (__h->e_machine != EM_MIPS) \
+ if (!mips_elf_check_machine(__h)) \
__res = 0; \
if (__h->e_ident[EI_CLASS] != ELFCLASS32) \
__res = 0; \
--
2.5.0