Index: sys/compat/linux/linux_time.c
===================================================================
--- sys/compat/linux/linux_time.c
+++ sys/compat/linux/linux_time.c
@@ -142,7 +142,7 @@
 linux_to_native_timespec(struct timespec *ntp, struct l_timespec *ltp)
 {
 
-	if (ltp->tv_sec < 0 || ltp->tv_nsec < 0 || ltp->tv_nsec > 999999999)
+	if (!timespecvalid(ltp))
 		return (EINVAL);
 	ntp->tv_sec = ltp->tv_sec;
 	ntp->tv_nsec = ltp->tv_nsec;
@@ -165,7 +165,7 @@
 linux_to_native_timespec64(struct timespec *ntp, struct l_timespec64 *ltp64)
 {
 
-	if (ltp64->tv_sec < 0 || ltp64->tv_nsec < 0 || ltp64->tv_nsec > 999999999)
+	if (!timespecvalid(ltp64))
 		return (EINVAL);
 	ntp->tv_sec = ltp64->tv_sec;
 	ntp->tv_nsec = ltp64->tv_nsec;
Index: sys/kern/kern_event.c
===================================================================
--- sys/kern/kern_event.c
+++ sys/kern/kern_event.c
@@ -1930,8 +1930,7 @@
 
 	rsbt = 0;
 	if (tsp != NULL) {
-		if (tsp->tv_sec < 0 || tsp->tv_nsec < 0 ||
-		    tsp->tv_nsec >= 1000000000) {
+		if (!timespecvalid(tsp)) {
 			error = EINVAL;
 			goto done_nl;
 		}
Index: sys/kern/kern_time.c
===================================================================
--- sys/kern/kern_time.c
+++ sys/kern/kern_time.c
@@ -411,7 +411,7 @@
 		return (error);
 	if (clock_id != CLOCK_REALTIME)
 		return (EINVAL);
-	if (ats->tv_nsec < 0 || ats->tv_nsec >= NS_PER_SEC || ats->tv_sec < 0)
+	if (!timespecvalid(ats))
 		return (EINVAL);
 	if (!allow_insane_settime &&
 	    (ats->tv_sec > 8000ULL * 365 * 24 * 60 * 60 ||
@@ -1644,7 +1644,7 @@
 itimespecfix(struct timespec *ts)
 {
 
-	if (ts->tv_sec < 0 || ts->tv_nsec < 0 || ts->tv_nsec >= NS_PER_SEC)
+	if (!timespecvalid(ts))
 		return (EINVAL);
 	if ((UINT64_MAX - ts->tv_nsec) / NS_PER_SEC < ts->tv_sec)
 		return (EINVAL);
Index: sys/kern/kern_umtx.c
===================================================================
--- sys/kern/kern_umtx.c
+++ sys/kern/kern_umtx.c
@@ -3772,9 +3772,7 @@
 
 	error = copyin(uaddr, tsp, sizeof(*tsp));
 	if (error == 0) {
-		if (tsp->tv_sec < 0 ||
-		    tsp->tv_nsec >= 1000000000 ||
-		    tsp->tv_nsec < 0)
+		if (!timespecvalid(tsp))
 			error = EINVAL;
 	}
 	return (error);
@@ -4640,9 +4638,7 @@
 
 	error = copyin(uaddr, &ts32, sizeof(ts32));
 	if (error == 0) {
-		if (ts32.tv_sec < 0 ||
-		    ts32.tv_nsec >= 1000000000 ||
-		    ts32.tv_nsec < 0)
+		if (timespecvalid(&ts32))
 			error = EINVAL;
 		else {
 			CP(ts32, *tsp, tv_sec);
@@ -4704,9 +4700,7 @@
 
 	error = copyin(uaddr, &ts32, sizeof(ts32));
 	if (error == 0) {
-		if (ts32.tv_sec < 0 ||
-		    ts32.tv_nsec >= 1000000000 ||
-		    ts32.tv_nsec < 0)
+		if (timespecvalid(&ts32))
 			error = EINVAL;
 		else {
 			CP(ts32, *tsp, tv_sec);
@@ -4730,8 +4724,7 @@
 		error = copyin(uaddr, &t32, sizeof(t32));
 	if (error != 0)
 		return (error);
-	if (t32._timeout.tv_sec < 0 ||
-	    t32._timeout.tv_nsec >= 1000000000 || t32._timeout.tv_nsec < 0)
+	if (!timespecvalid(&t32._timeout))
 		return (EINVAL);
 	TS_CP(t32, *tp, _timeout);
 	CP(t32, *tp, _flags);
Index: sys/kern/sys_generic.c
===================================================================
--- sys/kern/sys_generic.c
+++ sys/kern/sys_generic.c
@@ -1501,9 +1501,7 @@
 
 	precision = 0;
 	if (tsp != NULL) {
-		if (tsp->tv_sec < 0)
-			return (EINVAL);
-		if (tsp->tv_nsec < 0 || tsp->tv_nsec >= 1000000000)
+		if (!timespecvalid(tsp))
 			return (EINVAL);
 		if (tsp->tv_sec == 0 && tsp->tv_nsec == 0)
 			sbt = 0;
Index: sys/sys/time.h
===================================================================
--- sys/sys/time.h
+++ sys/sys/time.h
@@ -404,6 +404,8 @@
 			(vsp)->tv_nsec += 1000000000L;			\
 		}							\
 	} while (0)
+#define	timespecvalid(tsp)	((tsp)->tv_sec >= 0 &&			\
+	    (tsp)->tv_nsec >= 0 && (tsp)->tv_nsec < 1000000000L)
 
 #ifdef _KERNEL