Re: [PATCH 06/25] x86, pkeys: PTE bits for storing protection key

[Thomas Gleixner]

On Mon, 28 Sep 2015, Dave Hansen wrote:
> From: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
> 
> Previous documentation has referred to these 4 bits as "ignored".
> That means that software could have made use of them.  But, as
> far as I know, the kernel never used them.
> 
> They are still ignored when protection keys is not enabled, so
> they could theoretically still get used for software purposes.
> 
> We also implement "empty" versions so that code that references
> to them can be optimized away by the compiler when the config
> option is not enabled.
> 
> Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>

Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
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