diff --git a/include/arch/aarch64/asm_macros.S b/include/arch/aarch64/asm_macros.S
index 6091f62..44f892c 100644
--- a/include/arch/aarch64/asm_macros.S
+++ b/include/arch/aarch64/asm_macros.S
@@ -292,4 +292,13 @@
 #endif
 	.endm
 
+	/*
+	 * Macro to unmask External Aborts by changing PSTATE.A bit.
+	 * Put explicit synchronization event to ensure newly unmasked interrupt
+	 * is taken immediately.
+	 */
+	.macro  unmask_async_ea
+	msr     daifclr, #DAIF_ABT_BIT
+	isb
+	.endm
 #endif /* ASM_MACROS_S */
diff --git a/include/bl31/ea_handle.h b/include/bl31/ea_handle.h
index 68f012c..7cd7b6a 100644
--- a/include/bl31/ea_handle.h
+++ b/include/bl31/ea_handle.h
@@ -21,4 +21,6 @@
 /* RAS event signalled as peripheral interrupt */
 #define ERROR_INTERRUPT		3
 
+#define ASYNC_EA_REPLAY_COUNTER	U(100)
+
 #endif /* EA_HANDLE_H */
diff --git a/include/lib/el3_runtime/aarch64/context.h b/include/lib/el3_runtime/aarch64/context.h
index 470d113..fb28505 100644
--- a/include/lib/el3_runtime/aarch64/context.h
+++ b/include/lib/el3_runtime/aarch64/context.h
@@ -63,7 +63,22 @@
 #define CTX_PMCR_EL0		U(0x28)
 #define CTX_IS_IN_EL3		U(0x30)
 #define CTX_MPAM3_EL3		U(0x38)
-#define CTX_EL3STATE_END	U(0x40) /* Align to the next 16 byte boundary */
+/* Constants required in supporting nested exception in EL3 */
+#define CTX_SAVED_ELR_EL3	U(0x40)
+/*
+ * General purpose flag, to save various EL3 states
+ * FFH mode : Used to identify if handling nested exception
+ * KFH mode : Used as counter value
+ */
+#define CTX_NESTED_EA_FLAG	U(0x48)
+#if HANDLE_EA_EL3_FIRST_NS
+ #define CTX_SAVED_ESR_EL3	U(0x50)
+ #define CTX_SAVED_SPSR_EL3	U(0x58)
+ #define CTX_SAVED_GPREG_LR	U(0x60)
+ #define CTX_EL3STATE_END	U(0x70) /* Align to the next 16 byte boundary */
+#else
+ #define CTX_EL3STATE_END	U(0x50) /* Align to the next 16 byte boundary */
+#endif
 
 /*******************************************************************************
  * Constants that allow assembler code to access members of and the