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authorPeter Collingbourne <pcc@google.com>2021-04-01 19:51:10 +0300
committerWill Deacon <will@kernel.org>2021-04-01 20:16:14 +0300
commit185f2e5f51c2029efd9dd26cceb968a44fe053c6 (patch)
tree5e63148fa791e725ad9f47b29ca6d8f213cb5b12
parent20109a859a9b514eb10c22b8a14b5704ffe93897 (diff)
downloadlinux-185f2e5f51c2029efd9dd26cceb968a44fe053c6.tar.xz
arm64: fix inline asm in load_unaligned_zeropad()
The inline asm's addr operand is marked as input-only, however in the case where an exception is taken it may be modified by the BIC instruction on the exception path. Fix the problem by using a temporary register as the destination register for the BIC instruction. Signed-off-by: Peter Collingbourne <pcc@google.com> Cc: stable@vger.kernel.org Link: https://linux-review.googlesource.com/id/I84538c8a2307d567b4f45bb20b715451005f9617 Link: https://lore.kernel.org/r/20210401165110.3952103-1-pcc@google.com Signed-off-by: Will Deacon <will@kernel.org>
-rw-r--r--arch/arm64/include/asm/word-at-a-time.h10
1 files changed, 5 insertions, 5 deletions
diff --git a/arch/arm64/include/asm/word-at-a-time.h b/arch/arm64/include/asm/word-at-a-time.h
index 3333950b5909..ea487218db79 100644
--- a/arch/arm64/include/asm/word-at-a-time.h
+++ b/arch/arm64/include/asm/word-at-a-time.h
@@ -53,7 +53,7 @@ static inline unsigned long find_zero(unsigned long mask)
*/
static inline unsigned long load_unaligned_zeropad(const void *addr)
{
- unsigned long ret, offset;
+ unsigned long ret, tmp;
/* Load word from unaligned pointer addr */
asm(
@@ -61,9 +61,9 @@ static inline unsigned long load_unaligned_zeropad(const void *addr)
"2:\n"
" .pushsection .fixup,\"ax\"\n"
" .align 2\n"
- "3: and %1, %2, #0x7\n"
- " bic %2, %2, #0x7\n"
- " ldr %0, [%2]\n"
+ "3: bic %1, %2, #0x7\n"
+ " ldr %0, [%1]\n"
+ " and %1, %2, #0x7\n"
" lsl %1, %1, #0x3\n"
#ifndef __AARCH64EB__
" lsr %0, %0, %1\n"
@@ -73,7 +73,7 @@ static inline unsigned long load_unaligned_zeropad(const void *addr)
" b 2b\n"
" .popsection\n"
_ASM_EXTABLE(1b, 3b)
- : "=&r" (ret), "=&r" (offset)
+ : "=&r" (ret), "=&r" (tmp)
: "r" (addr), "Q" (*(unsigned long *)addr));
return ret;