From mboxrd@z Thu Jan 1 00:00:00 1970 From: AKASHI Takahiro Subject: Re: [RFA][PATCH 25/27] arm64, ftrace: Remove check of obsolete variable function_trace_stop Date: Tue, 01 Jul 2014 20:33:07 +0900 Message-ID: <53B29C73.9090509@linaro.org> References: <20140626165221.736847419@goodmis.org> <20140626165853.482575534@goodmis.org> <20140627124421.GP26276@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-pa0-f48.google.com ([209.85.220.48]:58062 "EHLO mail-pa0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752050AbaGALdS (ORCPT ); Tue, 1 Jul 2014 07:33:18 -0400 Received: by mail-pa0-f48.google.com with SMTP id et14so10445675pad.21 for ; Tue, 01 Jul 2014 04:33:17 -0700 (PDT) In-Reply-To: <20140627124421.GP26276@arm.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Will Deacon , Steven Rostedt Cc: "linux-kernel@vger.kernel.org" , Ingo Molnar , Andrew Morton , Thomas Gleixner , Masami Hiramatsu , "H. Peter Anvin" , "linux-arch@vger.kernel.org" , "Rafael J. Wysocki" , Jiri Kosina , Josh Poimboeuf 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)" >> >> 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 >> Cc: Will Deacon >> Signed-off-by: Steven Rostedt >> --- >> arch/arm64/kernel/entry-ftrace.S | 5 ----- >> 1 file changed, 5 deletions(-) > > Acked-by: Will Deacon > > 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 >> >> >>