linux/arch/arm64/kernel/efi-entry.S

69 lines
1.5 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* EFI entry point.
*
* Copyright (C) 2013, 2014 Red Hat, Inc.
* Author: Mark Salter <msalter@redhat.com>
*/
#include <linux/linkage.h>
#include <linux/init.h>
#include <asm/assembler.h>
__INIT
SYM_CODE_START(efi_enter_kernel)
/*
* efi_pe_entry() will have copied the kernel image if necessary and we
* end up here with device tree address in x1 and the kernel entry
* point stored in x0. Save those values in registers which are
* callee preserved.
*/
ldr w2, =primary_entry_offset
add x19, x0, x2 // relocated Image entrypoint
mov x20, x1 // DTB address
/*
* Clean the copied Image to the PoC, and ensure it is not shadowed by
* stale icache entries from before relocation.
*/
ldr w1, =kernel_size
bl __clean_dcache_area_poc
ic ialluis
/*
* Clean the remainder of this routine to the PoC
* so that we can safely disable the MMU and caches.
*/
adr x0, 0f
ldr w1, 3f
bl __clean_dcache_area_poc
0:
/* Turn off Dcache and MMU */
mrs x0, CurrentEL
cmp x0, #CurrentEL_EL2
b.ne 1f
mrs x0, sctlr_el2
bic x0, x0, #1 << 0 // clear SCTLR.M
bic x0, x0, #1 << 2 // clear SCTLR.C
pre_disable_mmu_workaround
msr sctlr_el2, x0
isb
b 2f
1:
mrs x0, sctlr_el1
bic x0, x0, #1 << 0 // clear SCTLR.M
bic x0, x0, #1 << 2 // clear SCTLR.C
pre_disable_mmu_workaround
msr sctlr_el1, x0
isb
2:
/* Jump to kernel entry point */
mov x0, x20
mov x1, xzr
mov x2, xzr
mov x3, xzr
br x19
SYM_CODE_END(efi_enter_kernel)
3: .long . - 0b