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authorWill Deacon <will.deacon@arm.com>2012-07-19 14:51:05 +0400
committerWill Deacon <will.deacon@arm.com>2012-11-09 18:13:19 +0400
commitdbf62d50067e55a782583fe53c3d2a3d98b1f6f3 (patch)
tree1bca43e9824e79d97bc32445182fe91a6600e035 /arch/arm
parent0cbbbad63179652272cc5e18a68d69bfc8dd25ce (diff)
downloadlinux-dbf62d50067e55a782583fe53c3d2a3d98b1f6f3.tar.xz
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')
-rw-r--r--arch/arm/include/asm/pgtable-2level.h1
-rw-r--r--arch/arm/include/asm/pgtable-3level.h3
-rw-r--r--arch/arm/include/asm/pgtable.h4
-rw-r--r--arch/arm/mm/proc-v7-2level.S2
-rw-r--r--arch/arm/mm/proc-v7-3level.S2
5 files changed, 6 insertions, 6 deletions
diff --git a/arch/arm/include/asm/pgtable-2level.h b/arch/arm/include/asm/pgtable-2level.h
index 2317a71c8f8e..c44a1ecfc28a 100644
--- a/arch/arm/include/asm/pgtable-2level.h
+++ b/arch/arm/include/asm/pgtable-2level.h
@@ -115,6 +115,7 @@
* The PTE table pointer refers to the hardware entries; the "Linux"
* entries are stored 1024 bytes below.
*/
+#define L_PTE_VALID (_AT(pteval_t, 1) << 0) /* Valid */
#define L_PTE_PRESENT (_AT(pteval_t, 1) << 0)
#define L_PTE_YOUNG (_AT(pteval_t, 1) << 1)
#define L_PTE_FILE (_AT(pteval_t, 1) << 2) /* only when !PRESENT */
diff --git a/arch/arm/include/asm/pgtable-3level.h b/arch/arm/include/asm/pgtable-3level.h
index b24903549d1c..e32311a9abca 100644
--- a/arch/arm/include/asm/pgtable-3level.h
+++ b/arch/arm/include/asm/pgtable-3level.h
@@ -67,7 +67,8 @@
* These bits overlap with the hardware bits but the naming is preserved for
* consistency with the classic page table format.
*/
-#define L_PTE_PRESENT (_AT(pteval_t, 3) << 0) /* Valid */
+#define L_PTE_VALID (_AT(pteval_t, 1) << 0) /* Valid */
+#define L_PTE_PRESENT (_AT(pteval_t, 3) << 0) /* Present */
#define L_PTE_FILE (_AT(pteval_t, 1) << 2) /* only when !PRESENT */
#define L_PTE_USER (_AT(pteval_t, 1) << 6) /* AP[1] */
#define L_PTE_RDONLY (_AT(pteval_t, 1) << 7) /* AP[2] */
diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
index 08c12312a1f9..ccf34b6e9903 100644
--- a/arch/arm/include/asm/pgtable.h
+++ b/arch/arm/include/asm/pgtable.h
@@ -203,9 +203,7 @@ static inline pte_t *pmd_page_vaddr(pmd_t pmd)
#define pte_exec(pte) (!(pte_val(pte) & L_PTE_XN))
#define pte_special(pte) (0)
-#define pte_present_user(pte) \
- ((pte_val(pte) & (L_PTE_PRESENT | L_PTE_USER)) == \
- (L_PTE_PRESENT | L_PTE_USER))
+#define pte_present_user(pte) (pte_present(pte) && (pte_val(pte) & L_PTE_USER))
#if __LINUX_ARM_ARCH__ < 6
static inline void __sync_icache_dcache(pte_t pteval)
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]! )
diff --git a/arch/arm/mm/proc-v7-3level.S b/arch/arm/mm/proc-v7-3level.S
index 8de0f1dd1549..d23d067e1904 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