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authorWill Deacon <will.deacon@arm.com>2012-07-19 11:51:05 +0100
committerWill Deacon <will.deacon@arm.com>2012-11-09 14:13:19 +0000
commitdbf62d50067e55a782583fe53c3d2a3d98b1f6f3 (patch)
tree1bca43e9824e79d97bc32445182fe91a6600e035 /arch/arm/mm
parent0cbbbad63179652272cc5e18a68d69bfc8dd25ce (diff)
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 <will.deacon@arm.com>
Diffstat (limited to 'arch/arm/mm')
-rw-r--r--arch/arm/mm/proc-v7-2level.S2
-rw-r--r--arch/arm/mm/proc-v7-3level.S2
2 files changed, 2 insertions, 2 deletions
diff --git a/arch/arm/mm/proc-v7-2level.S b/arch/arm/mm/proc-v7-2level.S
index e37600b91b2..e755e9f8d1b 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]! )
diff --git a/arch/arm/mm/proc-v7-3level.S b/arch/arm/mm/proc-v7-3level.S
index 8de0f1dd154..d23d067e190 100644
--- a/arch/arm/mm/proc-v7-3level.S
+++ b/arch/arm/mm/proc-v7-3level.S
@@ -65,7 +65,7 @@ ENDPROC(cpu_v7_switch_mm)
*/
ENTRY(cpu_v7_set_pte_ext)
#ifdef CONFIG_MMU
- tst r2, #L_PTE_PRESENT
+ tst r2, #L_PTE_VALID
beq 1f
tst r3, #1 << (55 - 32) @ L_PTE_DIRTY
orreq r2, #L_PTE_RDONLY