diff --git a/kernel/smpboot.h b/kernel/smpboot.h
index 7943bbb..4cfbcb8 100644
--- a/kernel/smpboot.h
+++ b/kernel/smpboot.h
@@ -8,9 +8,11 @@
 #ifdef CONFIG_GENERIC_SMP_IDLE_THREAD
 struct task_struct *idle_thread_get(unsigned int cpu);
 void idle_thread_set_boot_cpu(void);
+void idle_threads_init(void);
 #else
 static inline struct task_struct *idle_thread_get(unsigned int cpu) { return NULL; }
 static inline void idle_thread_set_boot_cpu(void) { }
+static inline void idle_threads_init(unsigned int cpu) { }
 #endif
 
 #endif