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-rw-r--r--include/asm-generic/pgtable.h13
1 files changed, 13 insertions, 0 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