From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752793AbbJTPch (ORCPT ); Tue, 20 Oct 2015 11:32:37 -0400 Received: from foss.arm.com ([217.140.101.70]:55954 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752035AbbJTPcd (ORCPT ); Tue, 20 Oct 2015 11:32:33 -0400 Date: Tue, 20 Oct 2015 16:32:28 +0100 From: Catalin Marinas To: Steven Rostedt Cc: Will Deacon , Mark Rutland , zhouchengming1@huawei.com, Arnd Bergmann , xiexiuqi@huawei.com, Punit Agrawal , guohanjun@huawei.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Li Bin , dingtianhong@huawei.com, Christoffer Dall Subject: Re: [PATCH] arm64: ftrace: function_graph: dump real return addr in call trace Message-ID: <20151020153227.GL11226@e104818-lin.cambridge.arm.com> References: <1444911155-17480-1-git-send-email-huawei.libin@huawei.com> <6277407.jveniKQDxt@wuerfel> <20151015125133.GA29301@arm.com> <20151015101812.7cb6e917@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151015101812.7cb6e917@gandalf.local.home> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 15, 2015 at 10:18:12AM -0400, Steven Rostedt wrote: > On Thu, 15 Oct 2015 13:51:33 +0100 > Will Deacon wrote: > > > Is this the same old problem caused by e306dfd06fcb ("ARM64: unwind: Fix > > PC calculation")? I've said previously that I'm happy to revert that if > > we're the only architecture with this behaviour, but Akashi resisted > > because there are other issues with ftrace that he was hoping to address > > and they would resolve this too. > > Just a reference, but this patch is pretty much exactly what x86 > currently has. I wonder if I should make that function generic for all > archs to use. > > If you accept this patch, I can look at what archs do and pull out the > common code and place it into the core code and have the archs call > that instead. The difference I see from the sh and x86 version is that we have this -4 on arm64, introduced by e306dfd06fcb as Will mentioned above (it seemed to have caused more problems that it solved). I think we should revert that commit first just to be in line with other architectures and then apply additional fixes as needed. Question for Li Bin: is your patch still needed if we revert commit e306dfd06fcb? Thanks. -- Catalin