bl2u/aarch64/bl2u_entrypoint.S

/*
 * Copyright (c) 2015-2021, ARM Limited and Contributors. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <arch.h>
#include <asm_macros.S>
#include <common/bl_common.h>

	.globl	bl2u_entrypoint


func bl2u_entrypoint
	/*---------------------------------------------
	 * Store the extents of the tzram available to
	 * BL2U and other platform specific information
	 * for future use. x0 is currently not used.
	 * ---------------------------------------------
	 */
	mov	x20, x1
	mov	x21, x2

	/* ---------------------------------------------
	 * Set the exception vector to something sane.
	 * ---------------------------------------------
	 */
	adr	x0, early_exceptions
	msr	vbar_el1, x0
	isb

	/* ---------------------------------------------
	 * Enable the SError interrupt now that the
	 * exception vectors have been setup.
	 * ---------------------------------------------
	 */
	msr	daifclr, #DAIF_ABT_BIT

	/* ---------------------------------------------
	 * Enable the instruction cache, stack pointer
	 * and data access alignment checks and disable
	 * speculative loads.
	 * ---------------------------------------------
	 */
	mov	x1, #(SCTLR_I_BIT | SCTLR_A_BIT | SCTLR_SA_BIT)
	mrs	x0, sctlr_el1
	orr	x0, x0, x1
#if ENABLE_BTI
	/* Enable PAC branch type compatibility */
	bic     x0, x0, #(SCTLR_BT0_BIT | SCTLR_BT1_BIT)
#endif
	bic	x0, x0, #SCTLR_DSSBS_BIT
	msr	sctlr_el1, x0
	isb

	/* ---------------------------------------------
	 * Invalidate the RW memory used by the BL2U
	 * image. This includes the data and NOBITS
	 * sections. This is done to safeguard against
	 * possible corruption of this memory by dirty
	 * cache lines in a system cache as a result of
	 * use by an earlier boot loader stage.
	 * ---------------------------------------------
	 */
	adr	x0, __RW_START__
	adr	x1, __RW_END__
	sub	x1, x1, x0
	bl	inv_dcache_range

	/* ---------------------------------------------
	 * Zero out NOBITS sections. There are 2 of them:
	 *   - the .bss section;
	 *   - the coherent memory section.
	 * ---------------------------------------------
	 */
	adrp	x0, __BSS_START__
	add	x0, x0, :lo12:__BSS_START__
	adrp	x1, __BSS_END__
	add	x1, x1, :lo12:__BSS_END__
	sub	x1, x1, x0
	bl	zeromem

	/* --------------------------------------------
	 * Allocate a stack whose memory will be marked
	 * as Normal-IS-WBWA when the MMU is enabled.
	 * There is no risk of reading stale stack
	 * memory after enabling the MMU as only the
	 * primary cpu is running at the moment.
	 * --------------------------------------------
	 */
	bl	plat_set_my_stack

	/* ---------------------------------------------
	 * Initialize the stack protector canary before
	 * any C code is called.
	 * ---------------------------------------------
	 */
#if STACK_PROTECTOR_ENABLED
	bl	update_stack_protector_canary
#endif

	/* ---------------------------------------------
	 * Perform early platform setup & platform
	 * specific early arch. setup e.g. mmu setup
	 * ---------------------------------------------
	 */
	mov	x0, x20
	mov	x1, x21
	bl	bl2u_early_platform_setup
	bl	bl2u_plat_arch_setup

#if ENABLE_PAUTH
	/* ---------------------------------------------
	 * Program APIAKey_EL1
	 * and enable pointer authentication.
	 * ---------------------------------------------
	 */
	bl	pauth_init_enable_el1
#endif

	/* ---------------------------------------------
	 * Jump to bl2u_main function.
	 * ---------------------------------------------
	 */
	bl	bl2u_main

	/* ---------------------------------------------
	 * Should never reach this point.
	 * ---------------------------------------------
	 */
	no_ret	plat_panic_handler

endfunc bl2u_entrypoint