Messages in this thread | ![/](/images/icornerl.gif) | | Date | Wed, 28 Oct 2015 15:21:31 +0000 | From | Will Deacon <> | Subject | Re: [PATCH] arm64: ftrace: function_graph: dump real return addr in call trace |
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On Thu, Oct 22, 2015 at 08:55:43AM +0800, libin wrote: > 在 2015/10/20 23:32, Catalin Marinas 写道: > >On Thu, Oct 15, 2015 at 10:18:12AM -0400, Steven Rostedt wrote: > >>On Thu, 15 Oct 2015 13:51:33 +0100 > >>Will Deacon <will.deacon@arm.com> 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.
Well, there's still an argument for reverting e306dfd06fcb because it makes us behave differently to other architectures (in particular, arch/arm).
Will
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