On Fri, Jan 12, 2018 at 11:13:13PM +0100, Dominik Brodowski wrote:
> > @@ -209,6 +234,11 @@ static void __init spectre_v2_select_mitigation(void)
> > mode = retp_compiler() ? SPECTRE_V2_RETPOLINE_GENERIC :
> > SPECTRE_V2_RETPOLINE_MINIMAL;
> > setup_force_cpu_cap(X86_FEATURE_RETPOLINE);
> > + if (mode == SPECTRE_V2_RETPOLINE_GENERIC &&
> > + cpu_needs_underflow_protection()) {
> > + mode = SPECTRE_V2_RETPOLINE_UNDERFLOW;
> > + setup_force_cpu_cap(X86_FEATURE_RETURN_UNDERFLOW);
> > + }
> > }
>
> Why does this require a retp-compatible compiler to be enabled?
Without the compiler you have a lot of other problems already,
so it's fairly pointless.
-Andi
