on(cond, mutex, abstime, true));
+	return (cond_wait_common(cond, mutex, 0, abstime, true, false));
+}
+
+int
+__pthread_cond_clockwait(pthread_cond_t *cond, pthread_mutex_t *mutex,
+    clockid_t clockid, const struct timespec *abstime)
+{
+
+	if (abstime == NULL || abstime->tv_sec < 0 || abstime->tv_nsec < 0 ||
+	    abstime->tv_nsec >= 1000000000)
+		return (EINVAL);
+
+	return (cond_wait_common(cond, mutex, clockid, abstime, true, true));
 }
 
 static int
diff --git a/lib/libthr/thread/thr_umtx.c b/lib/libthr/thread/thr_umtx.c
index db63017a6a13..edd0dacdaff1 100644
--- a/lib/libthr/thread/thr_umtx.c
+++ b/lib/libthr/thread/thr_umtx.c
@@ -28,6 +28,7 @@
 
 #include "thr_private.h"
 #include "thr_umtx.h"
+#include <assert.h>
 
 void
 _thr_umutex_init(struct umutex *mtx)
@@ -242,20 +243,35 @@ _thr_ucond_init(struct ucond *cv)
 
 int
 _thr_ucond_wait(struct ucond *cv, struct umutex *m,
-    const struct timespec *timeout, int flags)
+    const struct timespec *timeout, const struct _umtx_time *utimep, int flags)
 {
 	struct pthread *curthread;
-
-	if (timeout != NULL && (timeout->tv_sec < 0 || (timeout->tv_sec == 0 &&
-	    timeout->tv_nsec <= 0))) {
+	const struct timespec *ts;
+	void *arg2;
+
+	assert(timeout == NULL || utimep == NULL);
+	if (timeout != NULL) {
+		ts = timeout;
+		arg2 = __DECONST(void *, timeout);
+		assert((flags & CVWAIT_UMTX_TIME) == 0);
+	} else if (utimep != NULL) {
+		ts = &utimep->_timeout;
+		arg2 = __DECONST(void *, utimep);
+		assert((flags & CVWAIT_UMTX_TIME) != 0);
+	} else {
+		ts = NULL;
+		arg2 = NULL;
+		assert((flags & CVWAIT_UMTX_TIME) == 0);
+	}
+	if (ts != NULL && (ts->tv_sec < 0 || (ts->tv_sec == 0 &&
+	    ts->tv_nsec <= 0))) {
 		curthread = _get_curthread();
 		_thr_umutex_unlock(m, TID(curthread));
                 return (ETIMEDOUT);
 	}
-	return (_umtx_op_err(cv, UMTX_OP_CV_WAIT, flags, m,
-	    __DECONST(void *, timeout)));
+	return (_umtx_op_err(cv, UMTX_OP_CV_WAIT, flags, m, arg2));
 }
- 
+
 int
 _thr_ucond_signal(struct ucond *cv)
 {
diff --git a/lib/libthr/thread/thr_umtx.h b/lib/libthr/thread/thr_umtx.h
index 89f70e4ab14f..4e1c08ca64e8 100644
--- a/lib/libthr/thread/thr_umtx.h
+++ b/lib/libthr/thread/thr_umtx.h
@@ -59,7 +59,8 @@ int _thr_umtx_timedwait_uint(volatile u_int *mtx, u_int exp, int clockid,
 	const struct timespec *timeout, int shared) __hidden;
 int _thr_umtx_wake(volatile void *mtx, int count, int shared) __hidden;
 int _thr_ucond_wait(struct ucond *cv, struct umutex *m,
-        const struct timespec *timeout, int flags) __hidden;
+        const struct timespec *timeout, const struct _umtx_time *utimep,
+	int flags) __hidden;
 void _thr_ucond_init(struct ucond *cv) __hidden;
 int _thr_ucond_signal(struct ucond *cv) __hidden;
 int _thr_ucond_broadcast(struct ucond *cv) __hidden;