1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * EFI entry point.
4 *
5 * Copyright (C) 2013, 2014 Red Hat, Inc.
6 * Author: Mark Salter <msalter@redhat.com>
7 */
8#include <linux/linkage.h>
9#include <linux/init.h>
10
11#include <asm/assembler.h>
12
13	__INIT
14
15SYM_CODE_START(efi_enter_kernel)
16	/*
17	 * efi_pe_entry() will have copied the kernel image if necessary and we
18	 * end up here with device tree address in x1 and the kernel entry
19	 * point stored in x0. Save those values in registers which are
20	 * callee preserved.
21	 */
22	ldr	w2, =primary_entry_offset
23	add	x19, x0, x2		// relocated Image entrypoint
24	mov	x20, x1			// DTB address
25
26	/*
27	 * Clean the copied Image to the PoC, and ensure it is not shadowed by
28	 * stale icache entries from before relocation.
29	 */
30	ldr	w1, =kernel_size
31	add	x1, x0, x1
32	bl	dcache_clean_poc
33	ic	ialluis
34
35	/*
36	 * Clean the remainder of this routine to the PoC
37	 * so that we can safely disable the MMU and caches.
38	 */
39	adr	x0, 0f
40	adr	x1, 3f
41	bl	dcache_clean_poc
420:
43	/* Turn off Dcache and MMU */
44	mrs	x0, CurrentEL
45	cmp	x0, #CurrentEL_EL2
46	b.ne	1f
47	mrs	x0, sctlr_el2
48	bic	x0, x0, #1 << 0	// clear SCTLR.M
49	bic	x0, x0, #1 << 2	// clear SCTLR.C
50	pre_disable_mmu_workaround
51	msr	sctlr_el2, x0
52	isb
53	b	2f
541:
55	mrs	x0, sctlr_el1
56	bic	x0, x0, #1 << 0	// clear SCTLR.M
57	bic	x0, x0, #1 << 2	// clear SCTLR.C
58	pre_disable_mmu_workaround
59	msr	sctlr_el1, x0
60	isb
612:
62	/* Jump to kernel entry point */
63	mov	x0, x20
64	mov	x1, xzr
65	mov	x2, xzr
66	mov	x3, xzr
67	br	x19
683:
69SYM_CODE_END(efi_enter_kernel)
70