summaryrefslogtreecommitdiffstats
path: root/arch/arm64/kernel/hibernate-asm.S
blob: dd14ab8c9f724fb923911b95a17c35d5ced6635c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
/*
 * Hibernate low-level support
 *
 * Copyright (C) 2016 ARM Ltd.
 * Author:	James Morse <james.morse@arm.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#include <linux/linkage.h>
#include <linux/errno.h>

#include <asm/asm-offsets.h>
#include <asm/assembler.h>
#include <asm/cputype.h>
#include <asm/memory.h>
#include <asm/page.h>
#include <asm/virt.h>

/*
 * To prevent the possibility of old and new partial table walks being visible
 * in the tlb, switch the ttbr to a zero page when we invalidate the old
 * records. D4.7.1 'General TLB maintenance requirements' in ARM DDI 0487A.i
 * Even switching to our copied tables will cause a changed output address at
 * each stage of the walk.
 */
.macro break_before_make_ttbr_switch zero_page, page_table, tmp
	phys_to_ttbr \tmp, \zero_page
	msr	ttbr1_el1, \tmp
	isb
	tlbi	vmalle1
	dsb	nsh
	phys_to_ttbr \tmp, \page_table
	msr	ttbr1_el1, \tmp
	isb
.endm


/*
 * Resume from hibernate
 *
 * Loads temporary page tables then restores the memory image.
 * Finally branches to cpu_resume() to restore the state saved by
 * swsusp_arch_suspend().
 *
 * Because this code has to be copied to a 'safe' page, it can't call out to
 * other functions by PC-relative address. Also remember that it may be
 * mid-way through over-writing other functions. For this reason it contains
 * code from flush_icache_range() and uses the copy_page() macro.
 *
 * This 'safe' page is mapped via ttbr0, and executed from there. This function
 * switches to a copy of the linear map in ttbr1, performs the restore, then
 * switches ttbr1 to the original kernel's swapper_pg_dir.
 *
 * All of memory gets written to, including code. We need to clean the kernel
 * text to the Point of Coherence (PoC) before secondary cores can be booted.
 * Because the kernel modules and executable pages mapped to user space are
 * also written as data, we clean all pages we touch to the Point of
 * Unification (PoU).
 *
 * x0: physical address of temporary page tables
 * x1: physical address of swapper page tables
 * x2: address of cpu_resume
 * x3: linear map address of restore_pblist in the current kernel
 * x4: physical address of __hyp_stub_vectors, or 0
 * x5: physical address of a  zero page that remains zero after resume
 */
.pushsection    ".hibernate_exit.text", "ax"
ENTRY(swsusp_arch_suspend_exit)
	/*
	 * We execute from ttbr0, change ttbr1 to our copied linear map tables
	 * with a break-before-make via the zero page
	 */
	break_before_make_ttbr_switch	x5, x0, x6

	mov	x21, x1
	mov	x30, x2
	mov	x24, x4
	mov	x25, x5

	/* walk the restore_pblist and use copy_page() to over-write memory */
	mov	x19, x3

1:	ldr	x10, [x19, #HIBERN_PBE_ORIG]
	mov	x0, x10
	ldr	x1, [x19, #HIBERN_PBE_ADDR]

	copy_page	x0, x1, x2, x3, x4, x5, x6, x7, x8, x9

	add	x1, x10, #PAGE_SIZE
	/* Clean the copied page to PoU - based on flush_icache_range() */
	raw_dcache_line_size x2, x3
	sub	x3, x2, #1
	bic	x4, x10, x3
2:	dc	cvau, x4	/* clean D line / unified line */
	add	x4, x4, x2
	cmp	x4, x1
	b.lo	2b

	ldr	x19, [x19, #HIBERN_PBE_NEXT]
	cbnz	x19, 1b
	dsb	ish		/* wait for PoU cleaning to finish */

	/* switch to the restored kernels page tables */
	break_before_make_ttbr_switch	x25, x21, x6

	ic	ialluis
	dsb	ish
	isb

	cbz	x24, 3f		/* Do we need to re-initialise EL2? */
	hvc	#0
3:	ret

	.ltorg
ENDPROC(swsusp_arch_suspend_exit)

/*
 * Restore the hyp stub.
 * This must be done before the hibernate page is unmapped by _cpu_resume(),
 * but happens before any of the hyp-stub's code is cleaned to PoC.
 *
 * x24: The physical address of __hyp_stub_vectors
 */
el1_sync:
	msr	vbar_el2, x24
	eret
ENDPROC(el1_sync)

.macro invalid_vector	label
\label:
	b \label
ENDPROC(\label)
.endm

	invalid_vector	el2_sync_invalid
	invalid_vector	el2_irq_invalid
	invalid_vector	el2_fiq_invalid
	invalid_vector	el2_error_invalid
	invalid_vector	el1_sync_invalid
	invalid_vector	el1_irq_invalid
	invalid_vector	el1_fiq_invalid
	invalid_vector	el1_error_invalid

/* el2 vectors - switch el2 here while we restore the memory image. */
	.align 11
ENTRY(hibernate_el2_vectors)
	ventry	el2_sync_invalid		// Synchronous EL2t
	ventry	el2_irq_invalid			// IRQ EL2t
	ventry	el2_fiq_invalid			// FIQ EL2t
	ventry	el2_error_invalid		// Error EL2t

	ventry	el2_sync_invalid		// Synchronous EL2h
	ventry	el2_irq_invalid			// IRQ EL2h
	ventry	el2_fiq_invalid			// FIQ EL2h
	ventry	el2_error_invalid		// Error EL2h

	ventry	el1_sync			// Synchronous 64-bit EL1
	ventry	el1_irq_invalid			// IRQ 64-bit EL1
	ventry	el1_fiq_invalid			// FIQ 64-bit EL1
	ventry	el1_error_invalid		// Error 64-bit EL1

	ventry	el1_sync_invalid		// Synchronous 32-bit EL1
	ventry	el1_irq_invalid			// IRQ 32-bit EL1
	ventry	el1_fiq_invalid			// FIQ 32-bit EL1
	ventry	el1_error_invalid		// Error 32-bit EL1
END(hibernate_el2_vectors)

.popsection