diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig
index d04ccd7..28f93a6 100644
--- a/arch/alpha/Kconfig
+++ b/arch/alpha/Kconfig
@@ -55,6 +55,9 @@
 	bool
 	default y
 
+config ARCH_DMA_ADDR_T_64BIT
+	def_bool y
+
 config NEED_DMA_MAP_STATE
        def_bool y