Re: [PATCH v2 4/8] x86/spec_ctrl: Add sysctl knobs to enable/disable SPEC_CTRL feature

[Woodhouse, David]

On Mon, 2018-01-08 at 18:42 +0100, Peter Zijlstra wrote:
> On Mon, Jan 08, 2018 at 09:28:12AM -0800, Tim Chen wrote:
> > On 01/08/2018 08:14 AM, Peter Zijlstra wrote:
> > > On Mon, Jan 08, 2018 at 01:47:07PM +0100, Peter Zijlstra wrote:
> > >>> a good suggestion, but we encountered some issues with it either
> > >>> crashing the kernel at boot or not properly turning on/off.
> > >Â
> > > The below boots, but I lack stuff to test the enabling.
> >Â
> > Peter,
> >Â
> > Thanks. Will give it a spin. One other concern is if
> > JUMP_LABEL is not configured, this may not work, and
> > we may still need fall back to a control variable.
> 
> Urgh yes.. I always forget about that case. Will the retpoline crud be
> backported to a GCC old enough to not have asm-goto? If not, we could
> make all of this simply require asm-goto.

I think HJ said he was planning to backport as far as 4.9. When was
asm-goto added?

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