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authorRichard Weinberger <richard@nod.at>2012-04-14 17:29:30 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-06-01 15:18:18 +0800
commitf09f8dad903d3c469bf11b49c2d4c5259906a153 (patch)
treea81c0c1be3b0e1809b5b028dca85cf587b873250 /arch/um
parent3d7a75d7dc0c8c8e60f8c40622b7e3519e702714 (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')
-rw-r--r--arch/um/include/asm/pgtable.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/um/include/asm/pgtable.h b/arch/um/include/asm/pgtable.h
index 9a61ee184eee..5888f1b83477 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.