1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * kexec for arm64
4 *
5 * Copyright (C) Linaro.
6 * Copyright (C) Huawei Futurewei Technologies.
7 */
8
9#include <linux/kexec.h>
10#include <linux/linkage.h>
11
12#include <asm/assembler.h>
13#include <asm/kexec.h>
14#include <asm/page.h>
15#include <asm/sysreg.h>
16
17/*
18 * arm64_relocate_new_kernel - Put a 2nd stage image in place and boot it.
19 *
20 * The memory that the old kernel occupies may be overwritten when coping the
21 * new image to its final location.  To assure that the
22 * arm64_relocate_new_kernel routine which does that copy is not overwritten,
23 * all code and data needed by arm64_relocate_new_kernel must be between the
24 * symbols arm64_relocate_new_kernel and arm64_relocate_new_kernel_end.  The
25 * machine_kexec() routine will copy arm64_relocate_new_kernel to the kexec
26 * control_code_page, a special page which has been set up to be preserved
27 * during the copy operation.
28 */
29ENTRY(arm64_relocate_new_kernel)
30
31	/* Setup the list loop variables. */
32	mov	x18, x2				/* x18 = dtb address */
33	mov	x17, x1				/* x17 = kimage_start */
34	mov	x16, x0				/* x16 = kimage_head */
35	raw_dcache_line_size x15, x0		/* x15 = dcache line size */
36	mov	x14, xzr			/* x14 = entry ptr */
37	mov	x13, xzr			/* x13 = copy dest */
38
39	/* Clear the sctlr_el2 flags. */
40	mrs	x0, CurrentEL
41	cmp	x0, #CurrentEL_EL2
42	b.ne	1f
43	mrs	x0, sctlr_el2
44	ldr	x1, =SCTLR_ELx_FLAGS
45	bic	x0, x0, x1
46	pre_disable_mmu_workaround
47	msr	sctlr_el2, x0
48	isb
491:
50
51	/* Check if the new image needs relocation. */
52	tbnz	x16, IND_DONE_BIT, .Ldone
53
54.Lloop:
55	and	x12, x16, PAGE_MASK		/* x12 = addr */
56
57	/* Test the entry flags. */
58.Ltest_source:
59	tbz	x16, IND_SOURCE_BIT, .Ltest_indirection
60
61	/* Invalidate dest page to PoC. */
62	mov     x0, x13
63	add     x20, x0, #PAGE_SIZE
64	sub     x1, x15, #1
65	bic     x0, x0, x1
662:	dc      ivac, x0
67	add     x0, x0, x15
68	cmp     x0, x20
69	b.lo    2b
70	dsb     sy
71
72	mov x20, x13
73	mov x21, x12
74	copy_page x20, x21, x0, x1, x2, x3, x4, x5, x6, x7
75
76	/* dest += PAGE_SIZE */
77	add	x13, x13, PAGE_SIZE
78	b	.Lnext
79
80.Ltest_indirection:
81	tbz	x16, IND_INDIRECTION_BIT, .Ltest_destination
82
83	/* ptr = addr */
84	mov	x14, x12
85	b	.Lnext
86
87.Ltest_destination:
88	tbz	x16, IND_DESTINATION_BIT, .Lnext
89
90	/* dest = addr */
91	mov	x13, x12
92
93.Lnext:
94	/* entry = *ptr++ */
95	ldr	x16, [x14], #8
96
97	/* while (!(entry & DONE)) */
98	tbz	x16, IND_DONE_BIT, .Lloop
99
100.Ldone:
101	/* wait for writes from copy_page to finish */
102	dsb	nsh
103	ic	iallu
104	dsb	nsh
105	isb
106
107	/* Start new image. */
108	mov	x0, x18
109	mov	x1, xzr
110	mov	x2, xzr
111	mov	x3, xzr
112	br	x17
113
114ENDPROC(arm64_relocate_new_kernel)
115
116.ltorg
117
118.align 3	/* To keep the 64-bit values below naturally aligned. */
119
120.Lcopy_end:
121.org	KEXEC_CONTROL_PAGE_SIZE
122
123/*
124 * arm64_relocate_new_kernel_size - Number of bytes to copy to the
125 * control_code_page.
126 */
127.globl arm64_relocate_new_kernel_size
128arm64_relocate_new_kernel_size:
129	.quad	.Lcopy_end - arm64_relocate_new_kernel
130