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From: Jinyang He <hejinyang@loongson.cn>
To: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>,
	linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org,
	Paul Burton <paulburton@kernel.org>,
	Jun-Ru Chang <jrjang@realtek.com>
Subject: [PATCH v2 3/4] MIPS: Fix get_frame_info() handing of function size
Date: Thu, 21 Jan 2021 13:31:37 +0800	[thread overview]
Message-ID: <1611207098-11381-4-git-send-email-hejinyang@loongson.cn> (raw)
In-Reply-To: <1611207098-11381-1-git-send-email-hejinyang@loongson.cn>

[1]: Commit b6c7a324df37b ("MIPS: Fix get_frame_info() handling of
                            microMIPS function size")
[2]: Commit 2b424cfc69728 ("MIPS: Remove function size check in
                            get_frame_info()")

First patch added a constant to check the number of iterations against.
Second patch fixed the situation that info->func_size is zero.

However, func_size member became useless after the second commit. Without
ip_end, the get frame_size operation may be out of range although KALLSYMS
enabled. Thus, check func_size first. Then make ip_end be the sum of ip
and a constant (512) if func_size is equal to 0. Otherwise make ip_end be
the sum of ip and func_size.

Signed-off-by: Jinyang He <hejinyang@loongson.cn>
---
 arch/mips/kernel/process.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index 74d7fd8..adf29f7 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -371,10 +371,8 @@ static inline int is_sp_move_ins(union mips_instruction *ip, int *frame_size)
 static int get_frame_info(struct mips_frame_info *info)
 {
 	bool is_mmips = IS_ENABLED(CONFIG_CPU_MICROMIPS);
-	union mips_instruction insn, *ip;
-	const unsigned int max_insns = 128;
+	union mips_instruction insn, *ip, *ip_end;
 	unsigned int last_insn_size = 0;
-	unsigned int i;
 	bool saw_jump = false;
 
 	info->pc_offset = -1;
@@ -384,7 +382,9 @@ static int get_frame_info(struct mips_frame_info *info)
 	if (!ip)
 		goto err;
 
-	for (i = 0; i < max_insns; i++) {
+	ip_end = (void *)ip + (info->func_size ? info->func_size : 512);
+
+	while (ip < ip_end) {
 		ip = (void *)ip + last_insn_size;
 
 		if (is_mmips && mm_insn_16bit(ip->halfword[0])) {
-- 
2.1.0


  parent reply	other threads:[~2021-01-21  5:35 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-21  5:31 [PATCH v2 0/4] MIPS: process: Some fixes and improvements about get_frame_info() Jinyang He
2021-01-21  5:31 ` [PATCH v2 1/4] MIPS: process: Remove unnecessary headers inclusion Jinyang He
2021-01-21  9:28   ` Huacai Chen
2021-01-21  5:31 ` [PATCH v2 2/4] MIPS: microMIPS: Fix the judgment of mm_jr16_op and mm_jalr_op Jinyang He
2021-02-07 21:31   ` Maciej W. Rozycki
2021-02-08  1:13     ` Jinyang He
2021-02-09 16:14     ` Thomas Bogendoerfer
2021-01-21  5:31 ` Jinyang He [this message]
2021-01-21  5:31 ` [PATCH v2 4/4] MIPS: Add is_jr_ra_ins() to end the loop early Jinyang He
2021-01-25 11:24 ` [PATCH v2 0/4] MIPS: process: Some fixes and improvements about get_frame_info() Thomas Bogendoerfer

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