diff --git a/sys/cddl/compat/opensolaris/kern/opensolaris_atomic.c b/sys/cddl/compat/opensolaris/kern/opensolaris_atomic.c
index ee103557e686..c82772242fec 100644
--- a/sys/cddl/compat/opensolaris/kern/opensolaris_atomic.c
+++ b/sys/cddl/compat/opensolaris/kern/opensolaris_atomic.c
@@ -71,6 +71,29 @@ atomic_dec_64(volatile uint64_t *target)
 	*target -= 1;
 	mtx_unlock(&atomic_mtx);
 }
+
+uint64_t
+atomic_swap_64(volatile uint64_t *a, uint64_t value)
+{
+	uint64_t ret;
+
+	mtx_lock(&atomic_mtx);
+	ret = *a;
+	*a = value;
+	mtx_unlock(&atomic_mtx);
+	return (ret);
+}
+
+uint64_t
+atomic_load_64(volatile uint64_t *a)
+{
+	uint64_t ret;
+
+	mtx_lock(&atomic_mtx);
+	ret = *a;
+	mtx_unlock(&atomic_mtx);
+	return (ret);
+}
 #endif
 
 uint64_t
diff --git a/sys/cddl/compat/opensolaris/sys/atomic.h b/sys/cddl/compat/opensolaris/sys/atomic.h
index 92b9e10978b6..700e60251bd5 100644
--- a/sys/cddl/compat/opensolaris/sys/atomic.h
+++ b/sys/cddl/compat/opensolaris/sys/atomic.h
@@ -44,6 +44,8 @@
     !defined(ARM_HAVE_ATOMIC64) && !defined(I386_HAVE_ATOMIC64)
 extern void atomic_add_64(volatile uint64_t *target, int64_t delta);
 extern void atomic_dec_64(volatile uint64_t *target);
+extern uint64_t atomic_swap_64(volatile uint64_t *a, uint64_t value);
+extern uint64_t atomic_load_64(volatile uint64_t *a);
 #endif
 #ifndef __sparc64__
 extern uint32_t atomic_cas_32(volatile uint32_t *target, uint32_t cmp,