diff --git a/include/asm-ia64/system.h b/include/asm-ia64/system.h
index cd4233d..2f36205 100644
--- a/include/asm-ia64/system.h
+++ b/include/asm-ia64/system.h
@@ -265,6 +265,8 @@
 
 #define arch_align_stack(x) (x)
 
+void default_idle(void);
+
 #endif /* __KERNEL__ */
 
 #endif /* __ASSEMBLY__ */