Re: [PATCH] function:stacktrace/mips: Fix function:stacktrace for mips

From: yuanjunqing
Date: Fri May 29 2020 - 05:29:31 EST


May I ask if you have received this email.

在 2020/5/28 下午8:36, YuanJunQing 写道:
> ftrace_call as global symbol in ftrace_caller(), this
> will cause function:stacktrace can not work well.
> i.e. echo do_IRQ:stacktrace > set_ftrace_filte
>
> Signed-off-by: YuanJunQing <yuanjunqing66@xxxxxxx>
> ---
> arch/mips/kernel/mcount.S | 13 +++++++++++--
> 1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/arch/mips/kernel/mcount.S b/arch/mips/kernel/mcount.S
> index cff52b283e03..cd5545764e5f 100644
> --- a/arch/mips/kernel/mcount.S
> +++ b/arch/mips/kernel/mcount.S
> @@ -87,8 +87,15 @@ EXPORT_SYMBOL(_mcount)
> PTR_LA t1, _etext
> sltu t3, t1, a0 /* t3 = (a0 > _etext) */
> or t1, t2, t3
> + PTR_LA t2, stlab-4 /* t2: "function:stacktrace" return address */
> + move a1, AT /* arg2: parent's return address */
> beqz t1, ftrace_call
> - nop
> + nop /* "function:stacktrace" return address */
> +stlab:
> + PTR_LA t2, stlab-4
> + /* ftrace_call_end: ftrace_call return address */
> + beq t2,ra, ftrace_call_end
> + nop
> #if defined(KBUILD_MCOUNT_RA_ADDRESS) && defined(CONFIG_32BIT)
> PTR_SUBU a0, a0, 16 /* arg1: adjust to module's recorded callsite */
> #else
> @@ -98,7 +105,9 @@ EXPORT_SYMBOL(_mcount)
> .globl ftrace_call
> ftrace_call:
> nop /* a placeholder for the call to a real tracing function */
> - move a1, AT /* arg2: parent's return address */
> + move ra, t2 /* t2: "function:stacktrace" return address */
> +
> +ftrace_call_end:
>
> #ifdef CONFIG_FUNCTION_GRAPH_TRACER
> .globl ftrace_graph_call