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From: Jinyang He <hejinyang@loongson.cn>
To: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org,
	Paul Burton <paulburton@kernel.org>,
	Jun-Ru Chang <jrjang@realtek.com>
Subject: [PATCH 2/4] MIPS: microMIPS: Fix the judgment of mm_jr16_op and mm_jalr_op
Date: Tue, 12 Jan 2021 20:29:15 +0800	[thread overview]
Message-ID: <1610454557-25867-3-git-send-email-hejinyang@loongson.cn> (raw)
In-Reply-To: <1610454557-25867-1-git-send-email-hejinyang@loongson.cn>

mm16_r5_format.rt is 5 bits, so directly judge the value if equal or not.
mm_jalr_op requires 7th to 16th bits. These 10 which bits generated by
shifting u_format.uimmediate by 6 may be affected by sign extension.
Thus, take out the 10 bits for comparison.

Without this patch, errors may occur, such as these bits are all ones.

Signed-off-by: Jinyang He <hejinyang@loongson.cn>
---
 arch/mips/kernel/process.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index 361bd28..94dfdf4 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -311,8 +311,8 @@ static inline int is_jump_ins(union mips_instruction *ip)
 	 * microMIPS is kind of more fun...
 	 */
 	if (mm_insn_16bit(ip->word >> 16)) {
-		if ((ip->mm16_r5_format.opcode == mm_pool16c_op &&
-		    (ip->mm16_r5_format.rt & mm_jr16_op) == mm_jr16_op))
+		if (ip->mm16_r5_format.opcode == mm_pool16c_op &&
+		    ip->mm16_r5_format.rt == mm_jr16_op)
 			return 1;
 		return 0;
 	}
@@ -324,7 +324,7 @@ static inline int is_jump_ins(union mips_instruction *ip)
 	if (ip->r_format.opcode != mm_pool32a_op ||
 			ip->r_format.func != mm_pool32axf_op)
 		return 0;
-	return ((ip->u_format.uimmediate >> 6) & mm_jalr_op) == mm_jalr_op;
+	return ((ip->u_format.uimmediate >> 6) & GENMASK(9,0)) == mm_jalr_op;
 #else
 	if (ip->j_format.opcode == j_op)
 		return 1;
-- 
2.1.0


  parent reply	other threads:[~2021-01-12 12:30 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-12 12:29 [PATCH 0/4] MIPS: process: Some fixes and improvements about get_frame_info() Jinyang He
2021-01-12 12:29 ` [PATCH 1/4] MIPS: process: Reorder header files Jinyang He
2021-01-13  0:27   ` Huacai Chen
2021-01-15 14:46   ` Thomas Bogendoerfer
2021-01-18 10:02     ` Jinyang He
2021-01-18 11:27       ` Jinyang He
2021-01-18 22:11       ` Thomas Bogendoerfer
2021-01-12 12:29 ` Jinyang He [this message]
2021-01-12 12:29 ` [PATCH 3/4] MIPS: Fix get_frame_info() handing of function size Jinyang He
2021-01-12 12:29 ` [PATCH 4/4] MIPS: Add is_jr_ra_ins() to end the loop early Jinyang He
2021-10-23 18:32   ` Maciej W. Rozycki
2021-10-25  2:11     ` Jinyang He
2021-01-18  1:51 ` [PATCH 0/4] MIPS: process: Some fixes and improvements about get_frame_info() Jiaxun Yang
2021-01-19  1:29   ` Jinyang He

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