[PATCH 3.16 093/133] MIPS: microMIPS: Fix detection of addiusp instruction

From: Ben Hutchings
Date: Tue Nov 21 2017 - 21:35:17 EST


3.16.51-rc1 review patch. If anyone has any objections, please let me know.

------------------

From: Matt Redfearn <matt.redfearn@xxxxxxxxxx>

commit b332fec0489295ee7a0aab4a89bd7257cd126f7f upstream.

The addiusp instruction uses the pool16d opcode, with bit 0 of the
immediate set. The test for the addiusp opcode erroneously did a logical
and of the immediate with mm_addiusp_func, which has value 1, so this
test always passes when the immediate is non-zero.

Fix the test by replacing the logical and with a bitwise and.

Fixes: 34c2f668d0f6 ("MIPS: microMIPS: Add unaligned access support.")
Signed-off-by: Matt Redfearn <matt.redfearn@xxxxxxxxxx>
Cc: Marcin Nowakowski <marcin.nowakowski@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Paul Burton <paul.burton@xxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Patchwork: https://patchwork.linux-mips.org/patch/16954/
Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
arch/mips/kernel/process.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -353,7 +353,7 @@ static inline int is_sp_move_ins(union m
*/
if (mm_insn_16bit(ip->halfword[1])) {
return (ip->mm16_r3_format.opcode == mm_pool16d_op &&
- ip->mm16_r3_format.simmediate && mm_addiusp_func) ||
+ ip->mm16_r3_format.simmediate & mm_addiusp_func) ||
(ip->mm16_r5_format.opcode == mm_pool16d_op &&
ip->mm16_r5_format.rt == 29);
}