diff --git a/sys/kern/kern_umtx.c b/sys/kern/kern_umtx.c
--- a/sys/kern/kern_umtx.c
+++ b/sys/kern/kern_umtx.c
@@ -175,7 +175,8 @@
 
 static inline void umtx_abs_timeout_init2(struct umtx_abs_timeout *timo,
     const struct _umtx_time *umtxtime);
-static int umtx_abs_timeout_gethz(struct umtx_abs_timeout *timo);
+static int umtx_abs_timeout_getsbt(struct umtx_abs_timeout *timo,
+    sbintime_t *sbt, int *flags);
 static inline void umtx_abs_timeout_update(struct umtx_abs_timeout *timo);
 
 static void umtx_shm_init(void);
@@ -717,14 +718,33 @@
 }
 
 static int
-umtx_abs_timeout_gethz(struct umtx_abs_timeout *timo)
+umtx_abs_timeout_getsbt(struct umtx_abs_timeout *timo, sbintime_t *sbt,
+    int *flags)
 {
 	struct timespec tts;
 
 	if (timespeccmp(&timo->end, &timo->cur, <=))
-		return (-1);
+		return (ETIMEDOUT);
 	timespecsub(&timo->end, &timo->cur, &tts);
-	return (tstohz(&tts));
+	switch (timo->clockid) {
+	case CLOCK_REALTIME:
+	case CLOCK_REALTIME_PRECISE:
+	case CLOCK_MONOTONIC:
+	case CLOCK_MONOTONIC_PRECISE:
+	case CLOCK_UPTIME:
+	case CLOCK_UPTIME_PRECISE:
+		if (tts.tv_sec >= (SBT_MAX >> 32))
+			*sbt = SBT_MAX;
+		else
+			*sbt = tstosbt(tts);
+		*flags = 0;
+		break;
+	default:
+		*sbt = tick_sbt * tstohz(&tts);
+		*flags = C_HARDCLOCK;
+		break;
+	}
+	return (0);
 }
 
 static uint32_t
@@ -749,7 +769,8 @@
     struct umtx_abs_timeout *abstime)
 {
 	struct umtxq_chain *uc;
-	int error, timo;
+	sbintime_t sbt = 0;
+	int error, flags = 0;
 
 	if (abstime != NULL && abstime->is_abs_real) {
 		curthread->td_rtcgen = atomic_load_acq_int(&rtc_generation);
@@ -764,14 +785,12 @@
 			break;
 		}
 		if (abstime != NULL) {
-			timo = umtx_abs_timeout_gethz(abstime);
-			if (timo < 0) {
-				error = ETIMEDOUT;
+			error = umtx_abs_timeout_getsbt(abstime, &sbt, &flags);
+			if (error != 0)
 				break;
-			}
-		} else
-			timo = 0;
-		error = msleep(uq, &uc->uc_lock, PCATCH | PDROP, wmesg, timo);
+		}
+		error = msleep_sbt(uq, &uc->uc_lock, PCATCH | PDROP, wmesg,
+		    sbt, 0, flags);
 		if (error == EINTR || error == ERESTART) {
 			umtxq_lock(&uq->uq_key);
 			break;