From mboxrd@z Thu Jan 1 00:00:00 1970 From: huawei.libin@huawei.com (libin) Date: Thu, 22 Oct 2015 08:55:43 +0800 Subject: [PATCH] arm64: ftrace: function_graph: dump real return addr in call trace In-Reply-To: <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> <20151020153227.GL11226@e104818-lin.cambridge.arm.com> Message-ID: <5628340F.5080902@huawei.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org ? 2015/10/20 23:32, Catalin Marinas ??: > 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? > It still be needed, but it can be implemented in generic for all archs as Steve suggested. Thanks, Li Bin > Thanks. >