[v2,03/11] arm64: Take into account ID_AA64PFR0_EL1.CSV3

[Alan Cox]

> > On systems that are not vulnerable to variant 3, this is an unnecessary
> > overhead.  
> 
> KASLR can be bypassed on CPUs that are not vulnerable to variant 3 simply
> by timing how long accesses to kernel addresses from EL0 take -- please read
> the original KAISER paper for details about that attack on x86. kpti
> mitigates that. If you don't care about KASLR, don't enable it (arguably
> it's useless without kpti).

KASLR is primarily of value for remote protection.

Alan