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

[WANG Xuerui]

On 2020/5/29 17:29, yuanjunqing wrote:

> May I ask if you have received this email.

At least I have received the complete thread in my inbox, so others may 
well have no problem.

It's not polite to ping maintainers just one day after sending your 
patch BTW; keep the patch submitting guide[1] under your pillow.

Lastly, don't top-post even though your message body is short.


[1]: 
https://www.kernel.org/doc/html/latest/process/submitting-patches.html#don-t-get-discouraged-or-impatient


And a bit of review while we're at it...

> 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.
Chinglish. I can't understand this despite being a Chinese myself...
> > i.e. echo do_IRQ:stacktrace > set_ftrace_filte
The commit message is truncated? I can't seem to make sense of this line.
> > 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