diff --git a/arch/csky/include/asm/processor.h b/arch/csky/include/asm/processor.h
index ea75d72dea86..e487a46d1c37 100644
--- a/arch/csky/include/asm/processor.h
+++ b/arch/csky/include/asm/processor.h
@@ -72,8 +72,6 @@ struct task_struct;
 /* Prepare to copy thread state - unlazy all lazy status */
 #define prepare_to_copy(tsk)    do { } while (0)
 
-extern int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
-
 unsigned long __get_wchan(struct task_struct *p);
 
 #define KSTK_EIP(tsk)		(task_pt_regs(tsk)->pc)