|
commit b050f87d13b5dc7ed82feb9a90f4529de58bdf25
|
|
Author: Felix Fietkau <nbd@openwrt.org>
|
|
Date: Wed Feb 19 19:20:10 2014 +0000
|
|
|
|
gcc: prevent the use of LDRD/STRD on ARMv5TE
|
|
|
|
These instructions are for 64-bit load/store. On ARMv5TE, the CPU
|
|
requires addresses to be aligned to 64-bit. When misaligned, behavior is
|
|
undefined (effectively either loads the same word twice on LDRD, or
|
|
corrupts surrounding memory on STRD).
|
|
|
|
On ARMv6 and newer, unaligned access is safe.
|
|
|
|
Removing these instructions for ARMv5TE is necessary, because GCC
|
|
ignores alignment information in pointers and does unsafe optimizations
|
|
that have shown up as bugs in various places.
|
|
|
|
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
|
|
|
|
SVN-Revision: 39638
|
|
|
|
--- a/gcc/config/arm/arm.h
|
|
+++ b/gcc/config/arm/arm.h
|
|
@@ -150,7 +150,7 @@ extern tree arm_fp16_type_node;
|
|
/* Thumb-1 only. */
|
|
#define TARGET_THUMB1_ONLY (TARGET_THUMB1 && !arm_arch_notm)
|
|
|
|
-#define TARGET_LDRD (arm_arch5e && ARM_DOUBLEWORD_ALIGN \
|
|
+#define TARGET_LDRD (arm_arch6 && ARM_DOUBLEWORD_ALIGN \
|
|
&& !TARGET_THUMB1)
|
|
|
|
#define TARGET_CRC32 (arm_arch_crc)
|