Re: [PATCH] arm64: ftrace: function_graph: dump real return addr in call trace

[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 <will.deacon@xxxxxxx> 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
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