linux-kernel - [PATCH v3 2/6] MIPS: microMIPS: Fix detection of addiusp instruction

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Date:   Tue, 8 Aug 2017 13:22:31 +0100
From:   Matt Redfearn <matt.redfearn@...tec.com>
To:     Ralf Baechle <ralf@...ux-mips.org>
CC:     <linux-mips@...ux-mips.org>,
        Matt Redfearn <matt.redfearn@...tec.com>,
        Marcin Nowakowski <marcin.nowakowski@...tec.com>,
        <linux-kernel@...r.kernel.org>, Ingo Molnar <mingo@...nel.org>,
        Paul Burton <paul.burton@...tec.com>
Subject: [PATCH v3 2/6] MIPS: microMIPS: Fix detection of addiusp instruction

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@...tec.com>

---

Changes in v3:
- New patch to fix detection of addiusp instruction

Changes in v2: None

 arch/mips/kernel/process.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index 5950ecf469e9..9d38faf01055 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -326,7 +326,7 @@ static inline int is_sp_move_ins(union mips_instruction *ip)
 	 */
 	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);
 	}
-- 
2.7.4