From: Paul Burton <paul.burton@imgtec.com>
Date: Mon, 7 Nov 2016 15:07:05 +0000 (+0000)
Subject: MIPS: Fix is_jump_ins() handling of 16b microMIPS instructions
X-Git-Tag: v3.12.72~51
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=553b06b1c7f2a49985d61692bc08972939b8b290;p=thirdparty%2Fkernel%2Fstable.git

MIPS: Fix is_jump_ins() handling of 16b microMIPS instructions

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: Jiri Slaby <jslaby@suse.cz>
---

diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index 664e61ef690b4..92cec1380f8c6 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -263,9 +263,14 @@ 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)