Merge branch 'upstream-fixes'

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