[PATCH 4/6] MIPS: Fix is_jump_ins() handling of 16b microMIPS instructions

[Paul Burton <paul.burton@imgtec.com>]

is_jump_ins() checks 16b instruction fields without verifying that the
instruction is indeed 16b, as is done by is_ra_save_ins() &
is_sp_move_ins(). Add the appropriate check.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Fixes: 34c2f668d0f6 ("MIPS: microMIPS: Add unaligned access support.")
Cc: linux-mips@linux-mips.org
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Leonid Yegoshin <leonid.yegoshin@imgtec.com>
Cc: <stable@vger.kernel.org> # v3.10+
---

 arch/mips/kernel/process.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index d56ef4b..298dc33 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -241,9 +241,14 @@ static inline int is_jump_ins(union mips_instruction *ip)
 	 *
 	 * microMIPS is kind of more fun...
 	 */
-	if ((ip->mm16_r5_format.opcode == mm_pool16c_op &&
-	    (ip->mm16_r5_format.rt & mm_jr16_op) == mm_jr16_op) ||
-	    ip->j_format.opcode == mm_jal32_op)
+	if (mm_insn_16bit(ip->halfword[1])) {
+		if ((ip->mm16_r5_format.opcode == mm_pool16c_op &&
+		    (ip->mm16_r5_format.rt & mm_jr16_op) == mm_jr16_op))
+			return 1;
+		return 0;
+	}
+
+	if (ip->j_format.opcode == mm_jal32_op)
 		return 1;
 	if (ip->r_format.opcode != mm_pool32a_op ||
 			ip->r_format.func != mm_pool32axf_op)
-- 
2.10.2