diff --git a/services/spd/trusty/trusty.mk b/services/spd/trusty/trusty.mk
index 920504c..2e51bd5 100644
--- a/services/spd/trusty/trusty.mk
+++ b/services/spd/trusty/trusty.mk
@@ -9,4 +9,8 @@
 SPD_SOURCES		:=	services/spd/trusty/trusty.c		\
 				services/spd/trusty/trusty_helpers.S
 
+ifeq (${TRUSTY_SPD_WITH_GENERIC_SERVICES},1)
+SPD_SOURCES		+=	services/spd/trusty/generic-arm64-smcall.c
+endif
+
 NEED_BL32		:=	yes