diff --git a/make_helpers/defaults.mk b/make_helpers/defaults.mk
index fab6bf6..42ebd33 100644
--- a/make_helpers/defaults.mk
+++ b/make_helpers/defaults.mk
@@ -160,6 +160,10 @@
 # Flag to enable access to the Random Number Generator registers
 ENABLE_FEAT_RNG			:= 0
 
+# Flag to enable support for EL3 trapping of reads of the RNDR and RNDRRS
+# registers, by setting SCR_EL3.TRNDR.
+ENABLE_FEAT_RNG_TRAP		:= 0
+
 # Flag to enable Speculation Barrier Instruction
 ENABLE_FEAT_SB			:= 0