[PATCH 3.8 061/133] arm64: Use Normal NonCacheable memory for writecombine

[Kamal Mostafa]

3.8.13.22 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Catalin Marinas <catalin.marinas at arm.com>

commit 4f00130b70e5eee813cc7bc298e0f3fdf79673cc upstream.

This provides better performance compared to Device GRE and also allows
unaligned accesses. Such memory is intended to be used with standard RAM
(e.g. framebuffers) and not I/O.

Signed-off-by: Catalin Marinas <catalin.marinas at arm.com>
[ kamal: 3.8-stable prereq for de2db74 "arm64: Make DMA coherent and strongly
  ordered mappings not executable" ]
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 arch/arm64/include/asm/pgtable.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 72dd657..feb0684 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -184,7 +184,7 @@ static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
 #define pgprot_noncached(prot) \
 	__pgprot_modify(prot, PTE_ATTRINDX_MASK, PTE_ATTRINDX(MT_DEVICE_nGnRnE))
 #define pgprot_writecombine(prot) \
-	__pgprot_modify(prot, PTE_ATTRINDX_MASK, PTE_ATTRINDX(MT_DEVICE_GRE))
+	__pgprot_modify(prot, PTE_ATTRINDX_MASK, PTE_ATTRINDX(MT_NORMAL_NC))
 #define pgprot_dmacoherent(prot) \
 	__pgprot_modify(prot, PTE_ATTRINDX_MASK, PTE_ATTRINDX(MT_NORMAL_NC))
 #define __HAVE_PHYS_MEM_ACCESS_PROT
-- 
1.9.1