remap_file_pages: check file mapping

Change-Id: Ibf145a20181938a9825214253337a423fcd53064
Refs: #1521

kernel/include/memobj.h

@@ -37,6 +37,7 @@ enum {
 	MF_SHM =     0x40000,
 	MF_HUGETLBFS = 0x100000,
 	MF_PRIVATE   = 0x200000, /* To prevent flush in clear_range_* */
+	MF_REMAP_FILE_PAGES = 0x400000, /* remap_file_pages possible */
 };
 
 #define MEMOBJ_READY              0
@@ -181,4 +182,11 @@ static inline int is_freeable(struct memobj *memobj)
 	return 1;
 }
 
+static inline int is_callable_remap_file_pages(struct memobj *memobj)
+{
+	if (!memobj || !(memobj->flags & MF_REMAP_FILE_PAGES))
+		return 0;
+	return 1;
+}
+
 #endif /* HEADER_MEMOBJ_H */