linux-kernel - [PATCH] MIPS: Remove function size check in get_frame

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Date:   Tue, 29 Jan 2019 11:56:07 +0800
From:   Jun-Ru Chang <jrjang@...ltek.com>
To:     <ralf@...ux-mips.org>
CC:     <paul.burton@...s.com>, <jhogan@...nel.org>, <macro@...s.com>,
        <yamada.masahiro@...ionext.com>, <peterz@...radead.org>,
        <mingo@...nel.org>, <linux-mips@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <tonywu@...ltek.com>,
        <jrjang@...ltek.com>
Subject: [PATCH] MIPS: Remove function size check in get_frame_info()

Patch (b6c7a324df37b "MIPS: Fix get_frame_info() handling of
microMIPS function size.") introduces additional function size
check for microMIPS by only checking insn between ip and ip + func_size.
However, func_size in get_frame_info() is always 0 if KALLSYMS is not
enabled. This causes get_frame_info() to return immediately without
calculating correct frame_size, which in turn causes "Can't analyze
schedule() prologue" warning messages at boot time.

This patch removes func_size check, and let the frame_size check run
up to 128 insns for both MIPS and microMIPS.

Signed-off-by: Jun-Ru Chang <jrjang@...ltek.com>
Signed-off-by: Tony Wu <tonywu@...ltek.com>
Fixes: b6c7a324df37b ("MIPS: Fix get_frame_info() handling of microMIPS function size.")
---
 arch/mips/kernel/process.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index 6829a064aac8..339870ed92f7 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -371,7 +371,7 @@ 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, *ip_end;
+	union mips_instruction insn, *ip;
 	const unsigned int max_insns = 128;
 	unsigned int last_insn_size = 0;
 	unsigned int i;
@@ -384,10 +384,9 @@ static int get_frame_info(struct mips_frame_info *info)
 	if (!ip)
 		goto err;
 
-	ip_end = (void *)ip + info->func_size;
-
-	for (i = 0; i < max_insns && ip < ip_end; i++) {
+	for (i = 0; i < max_insns; i++) {
 		ip = (void *)ip + last_insn_size;
+
 		if (is_mmips && mm_insn_16bit(ip->halfword[0])) {
 			insn.word = ip->halfword[0] << 16;
 			last_insn_size = 2;
-- 
2.20.1