diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
index 5b20141..ef51d1f 100644
--- a/kernel/stop_machine.c
+++ b/kernel/stop_machine.c
@@ -375,6 +375,8 @@
 }
 early_initcall(cpu_stop_init);
 
+#ifdef CONFIG_STOP_MACHINE
+
 /* This controls the threads on each CPU. */
 enum stopmachine_state {
 	/* Dummy starting state for thread. */
@@ -477,3 +479,5 @@
 	return ret;
 }
 EXPORT_SYMBOL_GPL(stop_machine);
+
+#endif	/* CONFIG_STOP_MACHINE */