diff options
| author | Will Deacon <will.deacon@arm.com> | 2012-07-19 11:51:05 +0100 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2012-11-09 14:13:19 +0000 |
| commit | dbf62d50067e55a782583fe53c3d2a3d98b1f6f3 (patch) | |
| tree | 1bca43e9824e79d97bc32445182fe91a6600e035 /arch/arm/include/asm/pgtable-2level.h | |
| parent | 0cbbbad63179652272cc5e18a68d69bfc8dd25ce (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/include/asm/pgtable-2level.h')
| -rw-r--r-- | arch/arm/include/asm/pgtable-2level.h | 1 |
1 files changed, 1 insertions, 0 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 */ |