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-rw-r--r--include/asm-generic/pgtable.h13
-rw-r--r--include/asm-mips/pgtable.h2
-rw-r--r--mm/mremap.c6
3 files changed, 18 insertions, 3 deletions
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index f86c1e54946..ff28c8b31f5 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -158,6 +158,19 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addres
#define lazy_mmu_prot_update(pte) do { } while (0)
#endif
+#ifndef __HAVE_ARCH_MULTIPLE_ZERO_PAGE
+#define move_pte(pte, prot, old_addr, new_addr) (pte)
+#else
+#define move_pte(pte, prot, old_addr, new_addr) \
+({ \
+ pte_t newpte = (pte); \
+ if (pte_present(pte) && pfn_valid(pte_pfn(pte)) && \
+ pte_page(pte) == ZERO_PAGE(old_addr)) \
+ newpte = mk_pte(ZERO_PAGE(new_addr), (prot)); \
+ newpte; \
+})
+#endif
+
/*
* When walking page tables, get the address of the next boundary,
* or the end address of the range if that comes earlier. Although no
diff --git a/include/asm-mips/pgtable.h b/include/asm-mips/pgtable.h
index cbd1672c94c..eaf5d9b3a0e 100644
--- a/include/asm-mips/pgtable.h
+++ b/include/asm-mips/pgtable.h
@@ -68,6 +68,8 @@ extern unsigned long zero_page_mask;
#define ZERO_PAGE(vaddr) \
(virt_to_page(empty_zero_page + (((unsigned long)(vaddr)) & zero_page_mask)))
+#define __HAVE_ARCH_MULTIPLE_ZERO_PAGE
+
extern void paging_init(void);
/*
diff --git a/mm/mremap.c b/mm/mremap.c
index a32fed454bd..f343fc73a8b 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -141,10 +141,10 @@ move_one_page(struct vm_area_struct *vma, unsigned long old_addr,
if (dst) {
pte_t pte;
pte = ptep_clear_flush(vma, old_addr, src);
+
/* ZERO_PAGE can be dependant on virtual addr */
- if (pfn_valid(pte_pfn(pte)) &&
- pte_page(pte) == ZERO_PAGE(old_addr))
- pte = pte_wrprotect(mk_pte(ZERO_PAGE(new_addr), new_vma->vm_page_prot));
+ pte = move_pte(pte, new_vma->vm_page_prot,
+ old_addr, new_addr);
set_pte_at(mm, new_addr, dst, pte);
} else
error = -ENOMEM;