diff --git a/mm/mmap.c b/mm/mmap.c
index c1868ec..c7ed061 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -60,6 +60,13 @@
 	__S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111
 };
 
+pgprot_t vm_get_page_prot(unsigned long vm_flags)
+{
+	return protection_map[vm_flags &
+				(VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)];
+}
+EXPORT_SYMBOL(vm_get_page_prot);
+
 int sysctl_overcommit_memory = OVERCOMMIT_GUESS;  /* heuristic overcommit */
 int sysctl_overcommit_ratio = 50;	/* default is 50% */
 int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;