diff --git a/include/services/std_svc.h b/include/services/std_svc.h
index 0feb2ea..38ce8bb 100644
--- a/include/services/std_svc.h
+++ b/include/services/std_svc.h
@@ -42,4 +42,13 @@
 #define STD_SVC_VERSION_MAJOR		0x0
 #define STD_SVC_VERSION_MINOR		0x1
 
+/*
+ * Get the ARM Standard Service argument from EL3 Runtime.
+ * This function must be implemented by EL3 Runtime and the
+ * `svc_mask` identifies the service. `svc_mask` is a bit
+ * mask identifying the range of SMC function IDs available
+ * to the service.
+ */
+uintptr_t get_arm_std_svc_args(unsigned int svc_mask);
+
 #endif /* __STD_SVC_H__ */