Re: [PATCH] x86/retpoline: Fix NOSPEC_JMP for tip

From: Andi Kleen
Date: Tue Jan 09 2018 - 20:57:18 EST


On Wed, Jan 10, 2018 at 02:50:12AM +0100, Thomas Gleixner wrote:
> On Tue, 9 Jan 2018, Andi Kleen wrote:
>
> > > > I think there are areas that rely on X86_FEATURE_RETPOLINE being set
> > > > even if X86_FEATURE_RETPOLINE_AMD is set. For example, line 261 in
> > > > arch/x86/entry/entry_32.S is only checking for X86_FEATURE_RETPOLINE.
> > >
> > > I audited the difference places. They all seem ok.
> >
> > Actually 32bit is not ok. For 32bit we need COMMON. So adding it.
>
> Please keep the current X86_FEATURE_RETPOLINE as the common one and add a
> new X86_FEATURE_RETPOLINE_GENERIC which is selected by the generic/intel
> side. Little more churn, but clearer.

Ok, I just sent v2 without that. Will do a v3.

-Andi