diff options
| author | Richard Weinberger <richard@nod.at> | 2012-04-14 17:29:30 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-06-01 15:18:18 +0800 |
| commit | f09f8dad903d3c469bf11b49c2d4c5259906a153 (patch) | |
| tree | a81c0c1be3b0e1809b5b028dca85cf587b873250 /arch/um/include/asm/pgtable.h | |
| parent | 3d7a75d7dc0c8c8e60f8c40622b7e3519e702714 (diff) | |
um: Implement a custom pte_same() function
commit f15b9000eb1d09bbaa4b0a6b2089d7e1f64e84b3 upstream.
UML uses the _PAGE_NEWPAGE flag to mark pages which are not jet
installed on the host side using mmap().
pte_same() has to ignore this flag, otherwise unuse_pte_range()
is unable to unuse the page because two identical
page tables entries with different _PAGE_NEWPAGE flags would not
match and swapoff() would never return.
Analyzed-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/um/include/asm/pgtable.h')
| -rw-r--r-- | arch/um/include/asm/pgtable.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/um/include/asm/pgtable.h b/arch/um/include/asm/pgtable.h index 9a61ee184ee..5888f1b8347 100644 --- a/arch/um/include/asm/pgtable.h +++ b/arch/um/include/asm/pgtable.h @@ -273,6 +273,12 @@ static inline void set_pte(pte_t *pteptr, pte_t pteval) } #define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval) +#define __HAVE_ARCH_PTE_SAME +static inline int pte_same(pte_t pte_a, pte_t pte_b) +{ + return !((pte_val(pte_a) ^ pte_val(pte_b)) & ~_PAGE_NEWPAGE); +} + /* * Conversion functions: convert a page and protection to a page entry, * and a page entry and page directory to the page they refer to. |