diff --git a/vm/os-openbsd.hpp b/vm/os-openbsd.hpp
index 6a81a26be2..b3b47c08b3 100644
--- a/vm/os-openbsd.hpp
+++ b/vm/os-openbsd.hpp
@@ -1 +1 @@
-#define UAP_STACK_POINTER_TYPE __greg_t
+#define UAP_STACK_POINTER_TYPE __register_t