Re: [PATCH 1/3] x86/entry/64: Refactor IRQ stacks and make then NMI-safe

From: Andy Lutomirski
Date: Sat Jul 25 2015 - 00:59:41 EST


On Fri, Jul 24, 2015 at 9:32 PM, Borislav Petkov <bp@xxxxxxxxx> wrote:
> On Fri, Jul 24, 2015 at 09:28:47PM -0700, Andy Lutomirski wrote:
>> Yeah, I'm going to submit v2 with the simple approach. I admit I'm
>> rather fond of xadd as a way to switch rsp and set a flag at the same
>> time, though :)
>
> I know you are.
>
> But people will rip your head out if you added 60 cycles to the IRQ
> path.

And people will give me five new heads if I ignore Linus and do RET
even with IF=1, saving 300 cycles?

--Andy
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