arm: mm: introduce special ptes for LPAE
authorSteve Capper <steve.capper@linaro.org>
Thu, 9 Oct 2014 22:29:16 +0000 (15:29 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 10 Oct 2014 02:26:00 +0000 (22:26 -0400)
commitbd951303be5b4df578c7f30ef78839f1a9d6658c
tree573157dd8efc4de9a26b5e10f857840f8fcab02e
parent2667f50e8b81457fcb4a3dbe6aff3e81ea009e13
arm: mm: introduce special ptes for LPAE

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 <steve.capper@linaro.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dann Frazier <dann.frazier@canonical.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Christoffer Dall <christoffer.dall@linaro.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
arch/arm/include/asm/pgtable-2level.h
arch/arm/include/asm/pgtable-3level.h
arch/arm/include/asm/pgtable.h