Re: [RFA][PATCH 25/27] arm64, ftrace: Remove check of obsolete variable function_trace_stop

[AKASHI Takahiro]

On 06/27/2014 09:44 PM, Will Deacon wrote:
> Hi Steve,
>
> On Thu, Jun 26, 2014 at 05:52:46PM +0100, Steven Rostedt wrote:
> > From: "Steven Rostedt (Red Hat)" <rostedt@xxxxxxxxxxx>
> >
> > Nothing sets function_trace_stop to disable function tracing anymore.
> > Remove the check for it in the arch code.
> >
> > arm64 was broken anyway, as it had an ifdef testing
> >   CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST which is only set if
> > the arch supports the code (which it obviously did not), and
> > it was testing a non existent ftrace_trace_stop instead of
> > function_trace_stop.
>
> Yeah, the current code is total crap. Well spotted.

Thank you for fixing my bug :)
I also exercised ftrace with sysfs interface, and it just works well.

-Takahiro AKASHI

> > Cc: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx>
> > Cc: Will Deacon <will.deacon@xxxxxxx>
> > Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
> > ---
> >   arch/arm64/kernel/entry-ftrace.S | 5 -----
> >   1 file changed, 5 deletions(-)
>
>    Acked-by: Will Deacon <will.deacon@xxxxxxx>
>
> I'm happy for you to take this via the ftrace tree, along with the rest of
> the series.
>
> I successfully ran the ftrace self tests with this applied (on top of
> "ftrace: Remove check for HAVE_FUNCTION_TRACE_MCOUNT_TEST"), but note
> that I don't have a platform with working suspend/resume right now.
>
> Cheers,
>
> Will
>
> > diff --git a/arch/arm64/kernel/entry-ftrace.S b/arch/arm64/kernel/entry-ftrace.S
> > index b051871f2965..1b1e330e6849 100644
> > --- a/arch/arm64/kernel/entry-ftrace.S
> > +++ b/arch/arm64/kernel/entry-ftrace.S
> > @@ -96,11 +96,6 @@
> >    *     - ftrace_graph_caller to set up an exit hook
> >    */
> >   ENTRY(_mcount)
> > -#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
> > -	ldr	x0, =ftrace_trace_stop
> > -	ldr	x0, [x0]		// if ftrace_trace_stop
> > -	ret				//   return;
> > -#endif
> >   	mcount_enter
> >
> >   	ldr	x0, =ftrace_trace_function
> > --
> > 2.0.0
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