mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-12-15 15:53:02 +00:00
58 lines
1.7 KiB
C
58 lines
1.7 KiB
C
// SPDX-License-Identifier: GPL-2.0+
|
|
/*
|
|
* Switch to non-secure mode
|
|
*
|
|
* Copyright (c) 2018 Heinrich Schuchardt
|
|
*
|
|
* This module contains the ARMv8 specific code required to adjust the exception
|
|
* level before booting an operating system.
|
|
*/
|
|
|
|
#include <common.h>
|
|
#include <bootm.h>
|
|
#include <cpu_func.h>
|
|
#include <log.h>
|
|
#include <asm/cache.h>
|
|
#include <asm/setjmp.h>
|
|
|
|
/**
|
|
* entry_non_secure() - entry point when switching to non-secure mode
|
|
*
|
|
* When switching to non-secure mode switch_to_non_secure_mode() calls this
|
|
* function passing a jump buffer. We use this jump buffer to restore the
|
|
* original stack and register state.
|
|
*
|
|
* @non_secure_jmp: jump buffer for restoring stack and registers
|
|
*/
|
|
static void entry_non_secure(struct jmp_buf_data *non_secure_jmp)
|
|
{
|
|
dcache_enable();
|
|
debug("Reached non-secure mode\n");
|
|
|
|
/* Restore stack and registers saved in switch_to_non_secure_mode() */
|
|
longjmp(non_secure_jmp, 1);
|
|
}
|
|
|
|
/**
|
|
* switch_to_non_secure_mode() - switch to non-secure mode
|
|
*
|
|
* Exception level EL3 is meant to be used by the secure monitor only (ARM
|
|
* trusted firmware being one embodiment). The operating system shall be
|
|
* started at exception level EL2. So here we check the exception level
|
|
* and switch it if necessary.
|
|
*/
|
|
void switch_to_non_secure_mode(void)
|
|
{
|
|
struct jmp_buf_data non_secure_jmp;
|
|
|
|
/* On AArch64 we need to make sure we call our payload in < EL3 */
|
|
if (current_el() == 3) {
|
|
if (setjmp(&non_secure_jmp))
|
|
return;
|
|
dcache_disable(); /* flush cache before switch to EL2 */
|
|
|
|
/* Move into EL2 and keep running there */
|
|
armv8_switch_to_el2((uintptr_t)&non_secure_jmp, 0, 0, 0,
|
|
(uintptr_t)entry_non_secure, ES_TO_AARCH64);
|
|
}
|
|
}
|