Re: [PATCH 24/32] x86, pkeys: actually enable Memory Protection Keys in CPU

[Thomas Gleixner]

On Mon, 14 Dec 2015, Dave Hansen wrote:
> This sets the bit in 'cr4' to actually enable the protection
> keys feature.  We also include a boot-time disable for the
> feature "nopku".
> 
> Seting X86_CR4_PKE will cause the X86_FEATURE_OSPKE cpuid
> bit to appear set.  At this point in boot, identify_cpu()
> has already run the actual CPUID instructions and populated
> the "cpu features" structures.  We need to go back and
> re-run identify_cpu() to make sure it gets updated values.
> 
> We *could* simply re-populate the 11th word of the cpuid
> data, but this is probably quick enough.
> 
> Also note that with the cpu_has() check and X86_FEATURE_PKU
> present in disabled-features.h, we do not need an #ifdef
> for setup_pku().
> 
> Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>

Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
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