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 4/4] MIPS: Add is_jr_ra_ins() to end the loop early
Date: Tue, 12 Jan 2021 20:29:17 +0800 [thread overview]
Message-ID: <1610454557-25867-5-git-send-email-hejinyang@loongson.cn> (raw)
In-Reply-To: <1610454557-25867-1-git-send-email-hejinyang@loongson.cn>
For those leaf functions, they are likely to have no stack operations.
Add is_jr_ra_ins() to determine whether jr ra has been touched before
the frame_size is found. Without this patch, the get frame_size operation
may be out of range and get the frame_size from the next nested function.
Signed-off-by: Jinyang He <hejinyang@loongson.cn>
---
arch/mips/kernel/process.c | 34 +++++++++++++++++++++++++++++++++-
1 file changed, 33 insertions(+), 1 deletion(-)
diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index bef8f8d..9e6f194 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -205,6 +205,36 @@ struct mips_frame_info {
#define J_TARGET(pc,target) \
(((unsigned long)(pc) & 0xf0000000) | ((target) << 2))
+static inline int is_jr_ra_ins(union mips_instruction *ip)
+{
+#ifdef CONFIG_CPU_MICROMIPS
+ /*
+ * jr16 ra
+ * jr ra
+ */
+ if (mm_insn_16bit(ip->word >> 16)) {
+ if (ip->mm16_r5_format.opcode == mm_pool16c_op &&
+ ip->mm16_r5_format.rt == mm_jr16_op &&
+ ip->mm16_r5_format.imm == 31)
+ return 1;
+ return 0;
+ }
+
+ if (ip->r_format.opcode == mm_pool32a_op &&
+ ip->r_format.func == mm_pool32axf_op &&
+ ((ip->u_format.uimmediate >> 6) & GENMASK(9,0)) == mm_jalr_op &&
+ ip->r_format.rs == 31)
+ return 1;
+ return 0;
+#else
+ if (ip->r_format.opcode == spec_op &&
+ ip->r_format.func == jr_op &&
+ ip->r_format.rs == 31)
+ return 1;
+ return 0;
+#endif
+}
+
static inline int is_ra_save_ins(union mips_instruction *ip, int *poff)
{
#ifdef CONFIG_CPU_MICROMIPS
@@ -417,7 +447,9 @@ static int get_frame_info(struct mips_frame_info *info)
last_insn_size = 4;
}
- if (!info->frame_size) {
+ if (is_jr_ra_ins(ip)) {
+ break;
+ } else if (!info->frame_size) {
is_sp_move_ins(&insn, &info->frame_size);
continue;
} else if (!saw_jump && is_jump_ins(ip)) {
--
2.1.0
next prev parent reply other threads:[~2021-01-12 12:31 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 ` [PATCH 2/4] MIPS: microMIPS: Fix the judgment of mm_jr16_op and mm_jalr_op Jinyang He
2021-01-12 12:29 ` [PATCH 3/4] MIPS: Fix get_frame_info() handing of function size Jinyang He
2021-01-12 12:29 ` Jinyang He [this message]
2021-10-23 18:32 ` [PATCH 4/4] MIPS: Add is_jr_ra_ins() to end the loop early 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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