Factor out extension enabling to a separate function

Factor out extension enabling to a separate function that is called
before exiting from EL3 for first entry into Non-secure world.

Change-Id: Ic21401ebba531134d08643c0a1ca9de0fc590a1b
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>
diff --git a/lib/el3_runtime/aarch64/context_mgmt.c b/lib/el3_runtime/aarch64/context_mgmt.c
index c8232df..479acc9 100644
--- a/lib/el3_runtime/aarch64/context_mgmt.c
+++ b/lib/el3_runtime/aarch64/context_mgmt.c
@@ -209,6 +209,17 @@
 }
 
 /*******************************************************************************
+ * Enable architecture extensions on first entry to Non-secure world.
+ * When EL2 is implemented but unused `el2_unused` is non-zero, otherwise
+ * it is zero.
+ ******************************************************************************/
+static void enable_extensions_nonsecure(int el2_unused)
+{
+#if IMAGE_BL31
+#endif
+}
+
+/*******************************************************************************
  * The following function initializes the cpu_context for a CPU specified by
  * its `cpu_idx` for first use, and sets the initial entrypoint state as
  * specified by the entry_point_info structure.
@@ -245,6 +256,7 @@
 {
 	uint32_t sctlr_elx, scr_el3, mdcr_el2;
 	cpu_context_t *ctx = cm_get_context(security_state);
+	int el2_unused = 0;
 
 	assert(ctx);
 
@@ -258,6 +270,8 @@
 			sctlr_elx |= SCTLR_EL2_RES1;
 			write_sctlr_el2(sctlr_elx);
 		} else if (EL_IMPLEMENTED(2)) {
+			el2_unused = 1;
+
 			/*
 			 * EL2 present but unused, need to disable safely.
 			 * SCTLR_EL2 can be ignored in this case.
@@ -420,6 +434,7 @@
 			write_cnthp_ctl_el2(CNTHP_CTL_RESET_VAL &
 						~(CNTHP_CTL_ENABLE_BIT));
 		}
+		enable_extensions_nonsecure(el2_unused);
 	}
 
 	cm_el1_sysregs_context_restore(security_state);