diff --git a/arch/um/include/irq_user.h b/arch/um/include/irq_user.h
index 69a93c804f0e29cc1918e3919f959a42ab0d5c67..09e9e38920d5562956babaade5069e39a17c9dff 100644
--- a/arch/um/include/irq_user.h
+++ b/arch/um/include/irq_user.h
@@ -6,6 +6,8 @@
 #ifndef __IRQ_USER_H__
 #define __IRQ_USER_H__
 
+#include "uml-config.h"
+
 struct irq_fd {
 	struct irq_fd *next;
 	void *id;
@@ -26,9 +28,12 @@ extern void free_irq_by_fd(int fd);
 extern void reactivate_fd(int fd, int irqnum);
 extern void deactivate_fd(int fd, int irqnum);
 extern int deactivate_all_fds(void);
-extern void forward_interrupts(int pid);
 extern int activate_ipi(int fd, int pid);
 extern unsigned long irq_lock(void);
 extern void irq_unlock(unsigned long flags);
 
+#ifdef CONFIG_MODE_TT
+extern void forward_interrupts(int pid);
+#endif
+
 #endif
diff --git a/arch/um/kernel/irq.c b/arch/um/kernel/irq.c
index bfd0bdc8cd407e2b7502425cfb73072130f63ad7..519cdb0a7708ed28e26ee041d0703ace1671f440 100644
--- a/arch/um/kernel/irq.c
+++ b/arch/um/kernel/irq.c
@@ -350,6 +350,7 @@ int deactivate_all_fds(void)
 	return 0;
 }
 
+#ifdef CONFIG_MODE_TT
 void forward_interrupts(int pid)
 {
 	struct irq_fd *irq;
@@ -371,6 +372,7 @@ void forward_interrupts(int pid)
 	}
 	irq_unlock(flags);
 }
+#endif
 
 /*
  * do_IRQ handles all normal device IRQ's (the special