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| author | Will Deacon <will.deacon@arm.com> | 2012-07-19 12:51:05 +0200 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2012-11-09 15:13:19 +0100 |
| commit | dbf62d50067e55a782583fe53c3d2a3d98b1f6f3 (patch) | |
| tree | 1bca43e9824e79d97bc32445182fe91a6600e035 /arch/arm/mm/proc-v7-3level.S | |
| parent | ARM: mm: don't use the access flag permissions mechanism for classic MMU (diff) | |
| download | linux-dbf62d50067e55a782583fe53c3d2a3d98b1f6f3.tar.xz linux-dbf62d50067e55a782583fe53c3d2a3d98b1f6f3.zip | |
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/proc-v7-3level.S')
| -rw-r--r-- | arch/arm/mm/proc-v7-3level.S | 2 |
1 files changed, 1 insertions, 1 deletions
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 |