arm-trusted-firmware/bl2/aarch32/bl2_run_next_image.S
Zelalem Aweke 6c09af9f8b feat(rme): run BL2 in root world when FEAT_RME is enabled
This patch enables BL2 to run in root world (EL3) which is
needed as per the security model of RME-enabled systems.

Using the existing BL2_AT_EL3 TF-A build option is not convenient
because that option assumes TF-A BL1 doesn't exist, which is not
the case for RME-enabled systems. For the purposes of RME, we use
a normal BL1 image but we also want to run BL2 in EL3 as normally as
possible, therefore rather than use the special bl2_entrypoint
function in bl2_el3_entrypoint.S, we use a new bl2_entrypoint
function (in bl2_rme_entrypoint.S) which doesn't need reset or
mailbox initialization code seen in the el3_entrypoint_common macro.

The patch also cleans up bl2_el3_entrypoint.S, moving the
bl2_run_next_image function to its own file to avoid duplicating
code.

Signed-off-by: Zelalem Aweke <zelalem.aweke@arm.com>
Change-Id: I99821b4cd550cadcb701f4c0c4dc36da81c7ef55
2021-10-04 21:13:20 +02:00

46 lines
1 KiB
ArmAsm

/*
* Copyright (c) 2021, Arm Limited. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <arch.h>
#include <asm_macros.S>
#include <common/bl_common.h>
.globl bl2_run_next_image
func bl2_run_next_image
mov r8,r0
/*
* MMU needs to be disabled because both BL2 and BL32 execute
* in PL1, and therefore share the same address space.
* BL32 will initialize the address space according to its
* own requirement.
*/
bl disable_mmu_icache_secure
stcopr r0, TLBIALL
dsb sy
isb
mov r0, r8
bl bl2_el3_plat_prepare_exit
/*
* Extract PC and SPSR based on struct `entry_point_info_t`
* and load it in LR and SPSR registers respectively.
*/
ldr lr, [r8, #ENTRY_POINT_INFO_PC_OFFSET]
ldr r1, [r8, #(ENTRY_POINT_INFO_PC_OFFSET + 4)]
msr spsr_xc, r1
/* Some BL32 stages expect lr_svc to provide the BL33 entry address */
cps #MODE32_svc
ldr lr, [r8, #ENTRY_POINT_INFO_LR_SVC_OFFSET]
cps #MODE32_mon
add r8, r8, #ENTRY_POINT_INFO_ARGS_OFFSET
ldm r8, {r0, r1, r2, r3}
exception_return
endfunc bl2_run_next_image