diff --git a/arch/um/kernel/time.c b/arch/um/kernel/time.c
index 117568d..3936948 100644
--- a/arch/um/kernel/time.c
+++ b/arch/um/kernel/time.c
@@ -67,14 +67,14 @@ static irqreturn_t um_timer(int irq, void *dev)
 
 static cycle_t itimer_read(struct clocksource *cs)
 {
-	return os_nsecs() / 1000;
+	return os_nsecs();
 }
 
 static struct clocksource itimer_clocksource = {
 	.name		= "itimer",
 	.rating		= 300,
 	.read		= itimer_read,
-	.mask		= CLOCKSOURCE_MASK(64),
+	.mask		= CLOCKSOURCE_MASK(32),
 	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
@@ -92,7 +92,7 @@ static void __init setup_itimer(void)
 		clockevent_delta2ns(60 * HZ, &itimer_clockevent);
 	itimer_clockevent.min_delta_ns =
 		clockevent_delta2ns(1, &itimer_clockevent);
-	err = clocksource_register_hz(&itimer_clocksource, USEC_PER_SEC);
+	err = clocksource_register_hz(&itimer_clocksource, NSEC_PER_SEC);
 	if (err) {
 		printk(KERN_ERR "clocksource_register_hz returned %d\n", err);
 		return;