Re: [PATCH] x86/mm/pageattr: Use _PAGE_GLOBAL bit for EFI page table mappings

From: Matt Fleming
Date: Fri Jan 29 2016 - 11:26:05 EST


On Wed, 27 Jan, at 10:34:56AM, Sai Praneeth Prakhya wrote:
> From: Sai Praneeth <sai.praneeth.prakhya@xxxxxxxxx>
>
> Since EFI page tables can be treated as kernel page tables they should
> be global. All the other page mapping functions in pageattr.c set the
> _PAGE_GLOBAL bit and we want to avoid inconsistencies when we map a page
> in the EFI code paths, for example when that page is split in
> __split_large_page(), etc. It also makes it easier to validate that the
> EFI region mappings have the correct attributes because there are fewer
> differences compared with regular kernel mappings.
>
> Cc: Ricardo Neri <ricardo.neri@xxxxxxxxx>
> Cc: Ravi Shankar <ravi.v.shankar@xxxxxxxxx>
> Cc: Borislav Petkov <bp@xxxxxxxxx>
> Cc: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@xxxxxxxxx>
> ---
> arch/x86/mm/pageattr.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)

Reducing any differences between the EFI mapping and regular kernel
mapping code in pageattr.c is a plus.

Thanks Sai, applied.