2019-01-29 03:57:04

by Jun-Ru Chang

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 <[email protected]>
Signed-off-by: Tony Wu <[email protected]>
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

2019-02-04 23:22:58

by Paul Burton

Subject: Re: [PATCH] MIPS: Remove function size check in get_frame_info()

Hello,

Jun-Ru Chang wrote:
> 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 <[email protected]>
> Signed-off-by: Tony Wu <[email protected]>
> Fixes: b6c7a324df37b ("MIPS: Fix get_frame_info() handling of microMIPS function size.")

Applied to mips-fixes.

Thanks,
Paul

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