From dbf62d50067e55a782583fe53c3d2a3d98b1f6f3 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Thu, 19 Jul 2012 11:51:05 +0100 Subject: ARM: mm: introduce L_PTE_VALID for page table entries For long-descriptor translation table formats, the ARMv7 architecture defines the last two bits of the second- and third-level descriptors to be: x0b - Invalid 01b - Block (second-level), Reserved (third-level) 11b - Table (second-level), Page (third-level) This allows us to define L_PTE_PRESENT as (3 << 0) and use this value to create ptes directly. However, when determining whether a given pte value is present in the low-level page table accessors, we only need to check the least significant bit of the descriptor, allowing us to write faulting, present entries which are required for PROT_NONE mappings. This patch introduces L_PTE_VALID, which can be used to test whether a pte should fault, and updates the low-level page table accessors accordingly. Signed-off-by: Will Deacon --- arch/arm/mm/proc-v7-2level.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/arm/mm/proc-v7-2level.S') diff --git a/arch/arm/mm/proc-v7-2level.S b/arch/arm/mm/proc-v7-2level.S index e37600b91b25..e755e9f8d1b4 100644 --- a/arch/arm/mm/proc-v7-2level.S +++ b/arch/arm/mm/proc-v7-2level.S @@ -100,7 +100,7 @@ ENTRY(cpu_v7_set_pte_ext) orrne r3, r3, #PTE_EXT_XN tst r1, #L_PTE_YOUNG - tstne r1, #L_PTE_PRESENT + tstne r1, #L_PTE_VALID moveq r3, #0 ARM( str r3, [r0, #2048]! ) -- cgit v1.2.3