diff --git a/sys/cddl/dev/dtrace/powerpc/dtrace_subr.c b/sys/cddl/dev/dtrace/powerpc/dtrace_subr.c
index ed171f1135e9..0707a40aa22e 100644
--- a/sys/cddl/dev/dtrace/powerpc/dtrace_subr.c
+++ b/sys/cddl/dev/dtrace/powerpc/dtrace_subr.c
@@ -234,7 +234,7 @@ SYSINIT(dtrace_gethrtime_init, SI_SUB_SMP, SI_ORDER_ANY, dtrace_gethrtime_init,
  * Returns nanoseconds since boot.
  */
 uint64_t
-dtrace_gethrtime()
+dtrace_gethrtime(void)
 {
 	uint64_t timebase;
 	uint32_t lo;