diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h
index 3c9b391..a316e4a 100644
--- a/tools/perf/util/dso.h
+++ b/tools/perf/util/dso.h
@@ -139,6 +139,11 @@
 		struct list_head open_entry;
 	} data;
 
+	union { /* Tool specific area */
+		void	 *priv;
+		u64	 db_id;
+	};
+
 	char		 name[0];
 };