diff --git a/sys/powerpc/include/bus.h b/sys/powerpc/include/bus.h
--- a/sys/powerpc/include/bus.h
+++ b/sys/powerpc/include/bus.h
@@ -103,7 +103,7 @@
 	/* mapping/unmapping */
 	int	(*bs_map)(bus_addr_t, bus_size_t, int,
 	    bus_space_handle_t *);
-	void	(*bs_unmap)(bus_size_t);
+	void	(*bs_unmap)(bus_space_handle_t, bus_size_t);
 	int	(*bs_subregion)(bus_space_handle_t, bus_size_t,
 	    bus_size_t, bus_space_handle_t *);
 
diff --git a/sys/powerpc/powerpc/bus_machdep.c b/sys/powerpc/powerpc/bus_machdep.c
--- a/sys/powerpc/powerpc/bus_machdep.c
+++ b/sys/powerpc/powerpc/bus_machdep.c
@@ -140,8 +140,13 @@
 }
 
 static void
-bs_gen_unmap(bus_size_t size __unused)
+bs_gen_unmap(bus_space_handle_t bsh, bus_size_t size)
 {
+
+	if (!pmap_bootstrapped)
+		return;
+
+	pmap_unmapdev((void *)bsh, size);
 }
 
 static int