diff --git a/bl31/interrupt_mgmt.c b/bl31/interrupt_mgmt.c
index 2b0c797..e595634e 100644
--- a/bl31/interrupt_mgmt.c
+++ b/bl31/interrupt_mgmt.c
@@ -107,7 +107,7 @@
 {
 	uint32_t scr_el3;
 
-	assert(security_state <= NON_SECURE);
+	assert(sec_state_is_valid(security_state));
 	scr_el3 = intr_type_descs[INTR_TYPE_NS].scr_el3[security_state];
 	scr_el3 |= intr_type_descs[INTR_TYPE_S_EL1].scr_el3[security_state];
 	scr_el3 |= intr_type_descs[INTR_TYPE_EL3].scr_el3[security_state];