diff options
| author | Nick Piggin <npiggin@suse.de> | 2008-07-25 19:45:20 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-07-26 12:00:05 -0700 |
| commit | a0a8f5364a5ad248aec6cb705e0092ff563edc2f (patch) | |
| tree | fe942b13adc527f66103d529c2ee91da05086d1c | |
| parent | 2682497245e7d22160ae63032c378745a7f2cfe5 (diff) | |
x86: implement pte_special
Implement the pte_special bit for x86. This is required to support
lockless get_user_pages, because we need to know whether or not we can
refcount a particular page given only its pte (and no vma).
[hugh@veritas.com: fix a BUG]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Dave Kleikamp <shaggy@austin.ibm.com>
Cc: Andy Whitcroft <apw@shadowen.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Dave Kleikamp <shaggy@austin.ibm.com>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Zach Brown <zach.brown@oracle.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | include/asm-x86/pgtable.h | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/include/asm-x86/pgtable.h b/include/asm-x86/pgtable.h index 3e5dbc4195f..04caa2f544d 100644 --- a/include/asm-x86/pgtable.h +++ b/include/asm-x86/pgtable.h @@ -18,6 +18,7 @@ #define _PAGE_BIT_UNUSED2 10 #define _PAGE_BIT_UNUSED3 11 #define _PAGE_BIT_PAT_LARGE 12 /* On 2MB or 1GB pages */ +#define _PAGE_BIT_SPECIAL _PAGE_BIT_UNUSED1 #define _PAGE_BIT_NX 63 /* No execute: only valid after cpuid check */ #define _PAGE_PRESENT (_AT(pteval_t, 1) << _PAGE_BIT_PRESENT) @@ -34,6 +35,8 @@ #define _PAGE_UNUSED3 (_AT(pteval_t, 1) << _PAGE_BIT_UNUSED3) #define _PAGE_PAT (_AT(pteval_t, 1) << _PAGE_BIT_PAT) #define _PAGE_PAT_LARGE (_AT(pteval_t, 1) << _PAGE_BIT_PAT_LARGE) +#define _PAGE_SPECIAL (_AT(pteval_t, 1) << _PAGE_BIT_SPECIAL) +#define __HAVE_ARCH_PTE_SPECIAL #if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE) #define _PAGE_NX (_AT(pteval_t, 1) << _PAGE_BIT_NX) @@ -54,7 +57,7 @@ /* Set of bits not changed in pte_modify */ #define _PAGE_CHG_MASK (PTE_PFN_MASK | _PAGE_PCD | _PAGE_PWT | \ - _PAGE_ACCESSED | _PAGE_DIRTY) + _PAGE_SPECIAL | _PAGE_ACCESSED | _PAGE_DIRTY) #define _PAGE_CACHE_MASK (_PAGE_PCD | _PAGE_PWT) #define _PAGE_CACHE_WB (0) @@ -180,7 +183,7 @@ static inline int pte_exec(pte_t pte) static inline int pte_special(pte_t pte) { - return 0; + return pte_val(pte) & _PAGE_SPECIAL; } static inline int pmd_large(pmd_t pte) @@ -246,7 +249,7 @@ static inline pte_t pte_clrglobal(pte_t pte) static inline pte_t pte_mkspecial(pte_t pte) { - return pte; + return __pte(pte_val(pte) | _PAGE_SPECIAL); } extern pteval_t __supported_pte_mask; |