[PATCH 4.9 009/153] MIPS: Fix is_jump_ins() handling of 16b microMIPS instructions

Greg Kroah-Hartman
2017-03-10T11:32:22Z

From: Paul Burton <paul.burton@imgtec.com>

commit 67c75057709a6d85c681c78b9b2f9b71191f01a2 upstream.

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: Leonid Yegoshin <leonid.yegoshin@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14531/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -241,9 +241,14 @@ static inline int is_jump_ins(union mips
*
* 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)