diff --git a/include/lib/cpus/aarch64/cortex_a78.h b/include/lib/cpus/aarch64/cortex_a78.h
index 06c27ad..31da99e 100644
--- a/include/lib/cpus/aarch64/cortex_a78.h
+++ b/include/lib/cpus/aarch64/cortex_a78.h
@@ -38,6 +38,7 @@
 #define CORTEX_A78_ACTLR2_EL1_BIT_0			(ULL(1) << 0)
 #define CORTEX_A78_ACTLR2_EL1_BIT_1			(ULL(1) << 1)
 #define CORTEX_A78_ACTLR2_EL1_BIT_2			(ULL(1) << 2)
+#define CORTEX_A78_ACTLR2_EL1_BIT_40			(ULL(1) << 40)
 
 /*******************************************************************************
  * CPU Activity Monitor Unit register specific definitions.
diff --git a/include/lib/cpus/aarch64/cortex_a78_ae.h b/include/lib/cpus/aarch64/cortex_a78_ae.h
index 4108af5..b68ec1e 100644
--- a/include/lib/cpus/aarch64/cortex_a78_ae.h
+++ b/include/lib/cpus/aarch64/cortex_a78_ae.h
@@ -26,5 +26,6 @@
  ******************************************************************************/
 #define CORTEX_A78_AE_ACTLR2_EL1			CORTEX_A78_ACTLR2_EL1
 #define CORTEX_A78_AE_ACTLR2_EL1_BIT_0			CORTEX_A78_ACTLR2_EL1_BIT_0
+#define CORTEX_A78_AE_ACTLR2_EL1_BIT_40			CORTEX_A78_ACTLR2_EL1_BIT_40
 
 #endif /* CORTEX_A78_AE_H */