1/*
2 * kexec for arm64
3 *
4 * Copyright (C) Linaro.
5 * Copyright (C) Huawei Futurewei Technologies.
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 */
11
12#include <linux/kexec.h>
13#include <linux/linkage.h>
14
15#include <asm/assembler.h>
16#include <asm/kexec.h>
17#include <asm/page.h>
18#include <asm/sysreg.h>
19
20/*
21 * arm64_relocate_new_kernel - Put a 2nd stage image in place and boot it.
22 *
23 * The memory that the old kernel occupies may be overwritten when coping the
24 * new image to its final location.  To assure that the
25 * arm64_relocate_new_kernel routine which does that copy is not overwritten,
26 * all code and data needed by arm64_relocate_new_kernel must be between the
27 * symbols arm64_relocate_new_kernel and arm64_relocate_new_kernel_end.  The
28 * machine_kexec() routine will copy arm64_relocate_new_kernel to the kexec
29 * control_code_page, a special page which has been set up to be preserved
30 * during the copy operation.
31 */
32ENTRY(arm64_relocate_new_kernel)
33
34	/* Setup the list loop variables. */
35	mov	x17, x1				/* x17 = kimage_start */
36	mov	x16, x0				/* x16 = kimage_head */
37	dcache_line_size x15, x0		/* x15 = dcache line size */
38	mov	x14, xzr			/* x14 = entry ptr */
39	mov	x13, xzr			/* x13 = copy dest */
40
41	/* Clear the sctlr_el2 flags. */
42	mrs	x0, CurrentEL
43	cmp	x0, #CurrentEL_EL2
44	b.ne	1f
45	mrs	x0, sctlr_el2
46	ldr	x1, =SCTLR_ELx_FLAGS
47	bic	x0, x0, x1
48	msr	sctlr_el2, x0
49	isb
501:
51
52	/* Check if the new image needs relocation. */
53	tbnz	x16, IND_DONE_BIT, .Ldone
54
55.Lloop:
56	and	x12, x16, PAGE_MASK		/* x12 = addr */
57
58	/* Test the entry flags. */
59.Ltest_source:
60	tbz	x16, IND_SOURCE_BIT, .Ltest_indirection
61
62	/* Invalidate dest page to PoC. */
63	mov     x0, x13
64	add     x20, x0, #PAGE_SIZE
65	sub     x1, x15, #1
66	bic     x0, x0, x1
672:	dc      ivac, x0
68	add     x0, x0, x15
69	cmp     x0, x20
70	b.lo    2b
71	dsb     sy
72
73	mov x20, x13
74	mov x21, x12
75	copy_page x20, x21, x0, x1, x2, x3, x4, x5, x6, x7
76
77	/* dest += PAGE_SIZE */
78	add	x13, x13, PAGE_SIZE
79	b	.Lnext
80
81.Ltest_indirection:
82	tbz	x16, IND_INDIRECTION_BIT, .Ltest_destination
83
84	/* ptr = addr */
85	mov	x14, x12
86	b	.Lnext
87
88.Ltest_destination:
89	tbz	x16, IND_DESTINATION_BIT, .Lnext
90
91	/* dest = addr */
92	mov	x13, x12
93
94.Lnext:
95	/* entry = *ptr++ */
96	ldr	x16, [x14], #8
97
98	/* while (!(entry & DONE)) */
99	tbz	x16, IND_DONE_BIT, .Lloop
100
101.Ldone:
102	/* wait for writes from copy_page to finish */
103	dsb	nsh
104	ic	iallu
105	dsb	nsh
106	isb
107
108	/* Start new image. */
109	mov	x0, xzr
110	mov	x1, xzr
111	mov	x2, xzr
112	mov	x3, xzr
113	br	x17
114
115ENDPROC(arm64_relocate_new_kernel)
116
117.ltorg
118
119.align 3	/* To keep the 64-bit values below naturally aligned. */
120
121.Lcopy_end:
122.org	KEXEC_CONTROL_PAGE_SIZE
123
124/*
125 * arm64_relocate_new_kernel_size - Number of bytes to copy to the
126 * control_code_page.
127 */
128.globl arm64_relocate_new_kernel_size
129arm64_relocate_new_kernel_size:
130	.quad	.Lcopy_end - arm64_relocate_new_kernel
131