Re: [PATCH v24 04/30] x86/cpufeatures: Introduce X86_FEATURE_CET and setup functions

[Borislav Petkov]

On Fri, Apr 09, 2021 at 04:14:09PM -0700, Yu, Yu-cheng wrote:
> > @@ -53,6 +55,8 @@ static short xsave_cpuid_features[] __initdata = {
> >   	X86_FEATURE_INTEL_PT,
> >   	X86_FEATURE_PKU,
> >   	X86_FEATURE_ENQCMD,
> > +	X86_FEATURE_CET, /* XFEATURE_CET_USER */
> > +	X86_FEATURE_CET, /* XFEATURE_CET_KERNEL */
> > 
> > or what is the piece which becomes simpler?
> 
> Yes, this is it.

Those should be X86_FEATURE_SHSTK no?

> Signals, arch_prctl, and ELF header are three places that need to depend on
> either shadow stack or IBT is configured.  To remain simple, we can make all
> three depend on CONFIG_X86_SHADOW_STACK, and in Kconfig, make CONFIG_X86_IBT
> depend on CONFIG_X86_SHADOW_STACK.  Without shadow stack, IBT itself is not
> as useful anyway.

Makes sense to me.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette