bl2-el3: Add BL2_EL3 image

This patch enables BL2 to execute at the highest exception level
without any dependancy on TF BL1. This enables platforms which already
have a non-TF Boot ROM to directly load and execute BL2 and subsequent BL
stages without need for BL1.  This is not currently possible because
BL2 executes at S-EL1 and cannot jump straight to EL3.

Change-Id: Ief1efca4598560b1b8c8e61fbe26d1f44e929d69
Signed-off-by: Roberto Vargas <roberto.vargas@arm.com>

2 files changed, 208 insertions, 0 deletions

diff --git a/bl2/aarch64/bl2_el3_entrypoint.S b/bl2/aarch64/bl2_el3_entrypoint.S
new file mode 100644
index 00000000..2d3efd1f
--- /dev/null
+++ b/bl2/aarch64/bl2_el3_entrypoint.S
@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <arch.h>
+#include <asm_macros.S>
+#include <bl_common.h>
+#include <el3_common_macros.S>
+
+	.globl	bl2_entrypoint
+	.globl	bl2_vector_table
+	.globl	bl2_el3_run_image
+	.globl	bl2_run_next_image
+
+func bl2_entrypoint
+	/* Save arguments x0-x3 from previous Boot loader */
+	mov	x20, x0
+	mov	x21, x1
+	mov	x22, x2
+	mov	x23, x3
+
+	el3_entrypoint_common                                   \
+		_init_sctlr=1                                   \
+		_warm_boot_mailbox=!PROGRAMMABLE_RESET_ADDRESS  \
+		_secondary_cold_boot=!COLD_BOOT_SINGLE_CPU      \
+		_init_memory=1                                  \
+		_init_c_runtime=1                               \
+		_exception_vectors=bl2_el3_exceptions
+
+	/*
+	 * Restore parameters of boot rom
+	 */
+	mov	x0, x20
+	mov	x1, x21
+	mov	x2, x22
+	mov	x3, x23
+
+	bl	bl2_el3_early_platform_setup
+	bl	bl2_el3_plat_arch_setup
+
+	/* ---------------------------------------------
+	 * Jump to main function.
+	 * ---------------------------------------------
+	 */
+	bl	bl2_main
+
+	/* ---------------------------------------------
+	 * Should never reach this point.
+	 * ---------------------------------------------
+	 */
+	no_ret	plat_panic_handler
+endfunc bl2_entrypoint
+
+func bl2_run_next_image
+	mov	x20,x0
+        /*
+         * MMU needs to be disabled because both BL2 and BL31 execute
+         * in EL3, and therefore share the same address space.
+         * BL31 will initialize the address space according to its
+         * own requirement.
+         */
+	bl	disable_mmu_icache_el3
+	tlbi	alle3
+	bl	bl2_el3_plat_prepare_exit
+
+	ldp	x0, x1, [x20, #ENTRY_POINT_INFO_PC_OFFSET]
+	msr	elr_el3, x0
+	msr	spsr_el3, x1
+
+	ldp	x6, x7, [x20, #(ENTRY_POINT_INFO_ARGS_OFFSET + 0x30)]
+	ldp	x4, x5, [x20, #(ENTRY_POINT_INFO_ARGS_OFFSET + 0x20)]
+	ldp	x2, x3, [x20, #(ENTRY_POINT_INFO_ARGS_OFFSET + 0x10)]
+	ldp	x0, x1, [x20, #(ENTRY_POINT_INFO_ARGS_OFFSET + 0x0)]
+	eret
+endfunc bl2_run_next_image
diff --git a/bl2/aarch64/bl2_el3_exceptions.S b/bl2/aarch64/bl2_el3_exceptions.S
new file mode 100644
index 00000000..987f6e35
--- /dev/null
+++ b/bl2/aarch64/bl2_el3_exceptions.S
@@ -0,0 +1,131 @@
+/*
+ * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <arch.h>
+#include <asm_macros.S>
+#include <bl1.h>
+#include <bl_common.h>
+#include <context.h>
+
+/* -----------------------------------------------------------------------------
+ * Very simple stackless exception handlers used by BL2.
+ * -----------------------------------------------------------------------------
+ */
+	.globl	bl2_el3_exceptions
+
+vector_base bl2_el3_exceptions
+
+	/* -----------------------------------------------------
+	 * Current EL with SP0 : 0x0 - 0x200
+	 * -----------------------------------------------------
+	 */
+vector_entry SynchronousExceptionSP0
+	mov	x0, #SYNC_EXCEPTION_SP_EL0
+	bl	plat_report_exception
+	no_ret	plat_panic_handler
+	check_vector_size SynchronousExceptionSP0
+
+vector_entry IrqSP0
+	mov	x0, #IRQ_SP_EL0
+	bl	plat_report_exception
+	no_ret	plat_panic_handler
+	check_vector_size IrqSP0
+
+vector_entry FiqSP0
+	mov	x0, #FIQ_SP_EL0
+	bl	plat_report_exception
+	no_ret	plat_panic_handler
+	check_vector_size FiqSP0
+
+vector_entry SErrorSP0
+	mov	x0, #SERROR_SP_EL0
+	bl	plat_report_exception
+	no_ret	plat_panic_handler
+	check_vector_size SErrorSP0
+
+	/* -----------------------------------------------------
+	 * Current EL with SPx: 0x200 - 0x400
+	 * -----------------------------------------------------
+	 */
+vector_entry SynchronousExceptionSPx
+	mov	x0, #SYNC_EXCEPTION_SP_ELX
+	bl	plat_report_exception
+	no_ret	plat_panic_handler
+	check_vector_size SynchronousExceptionSPx
+
+vector_entry IrqSPx
+	mov	x0, #IRQ_SP_ELX
+	bl	plat_report_exception
+	no_ret	plat_panic_handler
+	check_vector_size IrqSPx
+
+vector_entry FiqSPx
+	mov	x0, #FIQ_SP_ELX
+	bl	plat_report_exception
+	no_ret	plat_panic_handler
+	check_vector_size FiqSPx
+
+vector_entry SErrorSPx
+	mov	x0, #SERROR_SP_ELX
+	bl	plat_report_exception
+	no_ret	plat_panic_handler
+	check_vector_size SErrorSPx
+
+	/* -----------------------------------------------------
+	 * Lower EL using AArch64 : 0x400 - 0x600
+	 * -----------------------------------------------------
+	 */
+vector_entry SynchronousExceptionA64
+	mov	x0, #SYNC_EXCEPTION_AARCH64
+	bl	plat_report_exception
+	no_ret	plat_panic_handler
+	check_vector_size SynchronousExceptionA64
+
+vector_entry IrqA64
+	mov	x0, #IRQ_AARCH64
+	bl	plat_report_exception
+	no_ret	plat_panic_handler
+	check_vector_size IrqA64
+
+vector_entry FiqA64
+	mov	x0, #FIQ_AARCH64
+	bl	plat_report_exception
+	no_ret	plat_panic_handler
+	check_vector_size FiqA64
+
+vector_entry SErrorA64
+	mov	x0, #SERROR_AARCH64
+	bl	plat_report_exception
+	no_ret	plat_panic_handler
+	check_vector_size SErrorA64
+
+	/* -----------------------------------------------------
+	 * Lower EL using AArch32 : 0x600 - 0x800
+	 * -----------------------------------------------------
+	 */
+vector_entry SynchronousExceptionA32
+	mov	x0, #SYNC_EXCEPTION_AARCH32
+	bl	plat_report_exception
+	no_ret	plat_panic_handler
+	check_vector_size SynchronousExceptionA32
+
+vector_entry IrqA32
+	mov	x0, #IRQ_AARCH32
+	bl	plat_report_exception
+	no_ret	plat_panic_handler
+	check_vector_size IrqA32
+
+vector_entry FiqA32
+	mov	x0, #FIQ_AARCH32
+	bl	plat_report_exception
+	no_ret	plat_panic_handler
+	check_vector_size FiqA32
+
+vector_entry SErrorA32
+	mov	x0, #SERROR_AARCH32
+	bl	plat_report_exception
+	no_ret	plat_panic_handler
+	check_vector_size SErrorA32