Re: [PATCH v8 1/7] arm64: Add HAVE_REGS_AND_STACK_ACCESS_API feature

Will Deacon
2015-08-18T09:38:24Z

Hi David,

On Thu, Aug 13, 2015 at 04:50:40AM +0100, David Long wrote:
> On 08/11/15 13:31, Will Deacon wrote:
> > On Tue, Aug 11, 2015 at 01:52:38AM +0100, David Long wrote:
> >> + REG_OFFSET_NAME(x30),
> >
> > Does this interact badly with perf tools, which expect to pass "lr" for
> > x30? (see tools/perf/arch/arm64/include/perf_regs.h).
> >
>
> Possibly, I can test that when I'm back from my short vacation this
> week. The lr/x30 thing seems to be a recurring issue. Perhaps it is
> best simply to add a reundant entry for x30 as "lr". It's simple enough
> to do, although just slightly ugly looking as it would have to be done
> without a macro. Would one ever use "x31" in place of "sp"?

No; "sp" should always be "sp". Let me know how you get on with perf. I
couldn't quite tie the two ends together, but it does look like it expects
"lr" to work.

Will