diff options
| author | Russell King <rmk@dyn-67.arm.linux.org.uk> | 2009-07-05 11:52:21 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2009-07-05 15:31:35 +0100 |
| commit | 65b1bfc13e8f50034187e339aa12b81cd6785bd5 (patch) | |
| tree | 6611d43eb749e2dbdd1074f57b0fa296530c5b39 | |
| parent | fb93a1c75eb646fde35985e9af23da936775ae52 (diff) | |
[ARM] pgtable: file pte layout documentation
Document the layout of our file PTE entries.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
| -rw-r--r-- | arch/arm/include/asm/pgtable.h | 23 |
1 files changed, 14 insertions, 9 deletions
diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h index c1d97938f3e..c433c6c7311 100644 --- a/arch/arm/include/asm/pgtable.h +++ b/arch/arm/include/asm/pgtable.h @@ -285,15 +285,6 @@ extern struct page *empty_zero_page; #define pte_young(pte) (pte_val(pte) & L_PTE_YOUNG) #define pte_special(pte) (0) -/* - * The following only works if pte_present() is not true. - */ -#define pte_file(pte) (pte_val(pte) & L_PTE_FILE) -#define pte_to_pgoff(x) (pte_val(x) >> 2) -#define pgoff_to_pte(x) __pte(((x) << 2) | L_PTE_FILE) - -#define PTE_FILE_MAX_BITS 30 - #define PTE_BIT_FUNC(fn,op) \ static inline pte_t pte_##fn(pte_t pte) { pte_val(pte) op; return pte; } @@ -414,6 +405,20 @@ extern pgd_t swapper_pg_dir[PTRS_PER_PGD]; */ #define MAX_SWAPFILES_CHECK() BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > __SWP_TYPE_BITS) +/* + * Encode and decode a file entry. File entries are stored in the Linux + * page tables as follows: + * + * 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 + * 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 + * <------------------------ offset -------------------------> 1 0 + */ +#define pte_file(pte) (pte_val(pte) & L_PTE_FILE) +#define pte_to_pgoff(x) (pte_val(x) >> 2) +#define pgoff_to_pte(x) __pte(((x) << 2) | L_PTE_FILE) + +#define PTE_FILE_MAX_BITS 30 + /* Needs to be defined here and not in linux/mm.h, as it is arch dependent */ /* FIXME: this is not correct */ #define kern_addr_valid(addr) (1) |