This is a note to let you know that I've just added the patch titled
ARM: Correct BUG() assembly to ensure it is endian-agnostic
to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arm-correct-bug-assembly-to-ensure-it-is-endian-agnostic.patch
and it can be found in the queue-3.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 63328070eff2f4fd730c86966a0dbc976147c39f Mon Sep 17 00:00:00 2001
From: Ben Dooks <ben.dooks@xxxxxxxxxxxxxxx>
Date: Thu, 25 Jul 2013 14:38:03 +0100
Subject: ARM: Correct BUG() assembly to ensure it is endian-agnostic
From: Ben Dooks <ben.dooks@xxxxxxxxxxxxxxx>
commit 63328070eff2f4fd730c86966a0dbc976147c39f upstream.
Currently BUG() uses .word or .hword to create the necessary illegal
instructions. However if we are building BE8 then these get swapped
by the linker into different illegal instructions in the text. This
means that the BUG() macro does not get trapped properly.
Change to using <asm/opcodes.h> to provide the necessary ARM instruction
building as we cannot rely on gcc/gas having the `.inst` instructions
which where added to try and resolve this issue (reported by Dave Martin
<Dave.Martin@xxxxxxx>).
Signed-off-by: Ben Dooks <ben.dooks@xxxxxxxxxxxxxxx>
Reviewed-by: Dave Martin <Dave.Martin@xxxxxxx>
Cc: Wang Nan <wangnan0@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm/include/asm/bug.h | 10 ++++++----
arch/arm/kernel/traps.c | 8 +++++---
2 files changed, 11 insertions(+), 7 deletions(-)
--- a/arch/arm/include/asm/bug.h
+++ b/arch/arm/include/asm/bug.h
@@ -2,6 +2,8 @@
#define _ASMARM_BUG_H
#include <linux/linkage.h>
+#include <linux/types.h>
+#include <asm/opcodes.h>
#ifdef CONFIG_BUG
@@ -12,10 +14,10 @@
*/
#ifdef CONFIG_THUMB2_KERNEL
#define BUG_INSTR_VALUE 0xde02
-#define BUG_INSTR_TYPE ".hword "
+#define BUG_INSTR(__value) __inst_thumb16(__value)
#else
#define BUG_INSTR_VALUE 0xe7f001f2
-#define BUG_INSTR_TYPE ".word "
+#define BUG_INSTR(__value) __inst_arm(__value)
#endif
@@ -33,7 +35,7 @@
#define __BUG(__file, __line, __value) \
do { \
- asm volatile("1:\t" BUG_INSTR_TYPE #__value "\n" \
+ asm volatile("1:\t" BUG_INSTR(__value) "\n" \
".pushsection .rodata.str, \"aMS\", %progbits, 1\n" \
"2:\t.asciz " #__file "\n" \
".popsection\n" \
@@ -48,7 +50,7 @@ do { \
#define __BUG(__file, __line, __value) \
do { \
- asm volatile(BUG_INSTR_TYPE #__value); \
+ asm volatile(BUG_INSTR(__value) "\n"); \
unreachable(); \
} while (0)
#endif /* CONFIG_DEBUG_BUGVERBOSE */
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -347,15 +347,17 @@ void arm_notify_die(const char *str, str
int is_valid_bugaddr(unsigned long pc)
{
#ifdef CONFIG_THUMB2_KERNEL
- unsigned short bkpt;
+ u16 bkpt;
+ u16 insn = __opcode_to_mem_thumb16(BUG_INSTR_VALUE);
#else
- unsigned long bkpt;
+ u32 bkpt;
+ u32 insn = __opcode_to_mem_arm(BUG_INSTR_VALUE);
#endif
if (probe_kernel_address((unsigned *)pc, bkpt))
return 0;
- return bkpt == BUG_INSTR_VALUE;
+ return bkpt == insn;
}
#endif
Patches currently in stable-queue which might be from ben.dooks@xxxxxxxxxxxxxxx are
queue-3.10/arm-probes-fix-instruction-fetch-order-with-asm-opcodes.h.patch
queue-3.10/arm-correct-bug-assembly-to-ensure-it-is-endian-agnostic.patch
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