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

[yuanjunqing]

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