On Wed, Aug 27, 2014 at 11:46:53AM +0100, Catalin Marinas wrote:

On Thu, Aug 21, 2014 at 04:43:28PM +0100, Steve Capper wrote:

quoted

We need a mechanism to tag ptes as being special, this indicates that
no attempt should be made to access the underlying struct page *
associated with the pte. This is used by the fast_gup when operating on
ptes as it has no means to access VMAs (that also contain this
information) locklessly.

The L_PTE_SPECIAL bit is already allocated for LPAE, this patch modifies
pte_special and pte_mkspecial to make use of it, and defines
__HAVE_ARCH_PTE_SPECIAL.

This patch also excludes special ptes from the icache/dcache sync logic.

Signed-off-by: Steve Capper <redacted>

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>

Thanks Catalin,
I've added this to the patch.
-- 
Steve

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