3 files changed, 18 insertions, 3 deletions

diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index f86c1e549466..ff28c8b31f58 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 cbd1672c94cb..eaf5d9b3a0e1 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 a32fed454bd7..f343fc73a8bd 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;