BL1: Enable pointer authentication support

The size increase after enabling options related to ARMv8.3-PAuth is:

+----------------------------+-------+-------+-------+--------+
|                            |  text |  bss  |  data | rodata |
+----------------------------+-------+-------+-------+--------+
| CTX_INCLUDE_PAUTH_REGS = 1 |  +108 |  +192 |   +0  |   +0   |
|                            |  0.5% |  0.8% |       |        |
+----------------------------+-------+-------+-------+--------+
| ENABLE_PAUTH = 1           |  +748 |  +192 |  +16  |   +0   |
|                            |  3.7% |  0.8% |  7.0% |        |
+----------------------------+-------+-------+-------+--------+

Results calculated with the following build configuration:

    make PLAT=fvp SPD=tspd DEBUG=1 \
    SDEI_SUPPORT=1                 \
    EL3_EXCEPTION_HANDLING=1       \
    TSP_NS_INTR_ASYNC_PREEMPT=1    \
    CTX_INCLUDE_PAUTH_REGS=1       \
    ENABLE_PAUTH=1

Change-Id: I3a7d02feb6a6d212be32a01432b0c7c1a261f567
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
diff --git a/bl1/aarch64/bl1_entrypoint.S b/bl1/aarch64/bl1_entrypoint.S
index f7e02e9..0f8d5aa 100644
--- a/bl1/aarch64/bl1_entrypoint.S
+++ b/bl1/aarch64/bl1_entrypoint.S
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013-2017, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2013-2019, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -32,24 +32,42 @@
 		_init_c_runtime=1				\
 		_exception_vectors=bl1_exceptions
 
-	/* ---------------------------------------------
-	 * Architectural init. can be generic e.g.
-	 * enabling stack alignment and platform spec-
-	 * ific e.g. MMU & page table setup as per the
-	 * platform memory map. Perform the latter here
-	 * and the former in bl1_main.
-	 * ---------------------------------------------
+	/* --------------------------------------------------------------------
+	 * Perform BL1 setup
+	 * --------------------------------------------------------------------
 	 */
-	bl	bl1_early_platform_setup
-	bl	bl1_plat_arch_setup
+	bl	bl1_setup
 
-	/* --------------------------------------------------
+	/* --------------------------------------------------------------------
+	 * Enable pointer authentication
+	 * --------------------------------------------------------------------
+	 */
+#if ENABLE_PAUTH
+	mrs	x0, sctlr_el3
+	orr	x0, x0, #SCTLR_EnIA_BIT
+	msr	sctlr_el3, x0
+	isb
+#endif /* ENABLE_PAUTH */
+
+	/* --------------------------------------------------------------------
 	 * Initialize platform and jump to our c-entry point
 	 * for this type of reset.
-	 * --------------------------------------------------
+	 * --------------------------------------------------------------------
 	 */
 	bl	bl1_main
 
+	/* --------------------------------------------------------------------
+	 * Disable pointer authentication before jumping to BL31 or that will
+	 * cause an authentication failure during the early platform init.
+	 * --------------------------------------------------------------------
+	 */
+#if ENABLE_PAUTH
+	mrs	x0, sctlr_el3
+	bic	x0, x0, #SCTLR_EnIA_BIT
+	msr	sctlr_el3, x0
+	isb
+#endif /* ENABLE_PAUTH */
+
 	/* --------------------------------------------------
 	 * Do the transition to next boot image.
 	 * --------------------------------------------------