diff --git a/arch/um/include/os.h b/arch/um/include/os.h
index e4f2fe1..91642e4 100644
--- a/arch/um/include/os.h
+++ b/arch/um/include/os.h
@@ -251,11 +251,10 @@
 /* time.c */
 #define BILLION (1000 * 1000 * 1000)
 
-extern int switch_timers(int to_real);
-extern void idle_sleep(int secs);
+extern void idle_sleep(unsigned long long nsecs);
 extern int set_interval(void);
 extern int timer_one_shot(int ticks);
-extern void disable_timer(void);
+extern unsigned long long disable_timer(void);
 extern void uml_idle_timer(void);
 extern unsigned long long os_nsecs(void);