diff --git a/bl31/bl31_main.c b/bl31/bl31_main.c
index 8cc7e0d..d949a08 100644
--- a/bl31/bl31_main.c
+++ b/bl31/bl31_main.c
@@ -56,7 +56,7 @@
 /*******************************************************************************
  * Simple function to initialise all BL31 helper libraries.
  ******************************************************************************/
-void bl31_lib_init()
+void bl31_lib_init(void)
 {
 	cm_init();
 }
@@ -137,7 +137,7 @@
  * This function programs EL3 registers and performs other setup to enable entry
  * into the next image after BL31 at the next ERET.
  ******************************************************************************/
-void bl31_prepare_next_image_entry()
+void bl31_prepare_next_image_entry(void)
 {
 	entry_point_info_t *next_image_info;
 	uint32_t image_type;