1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Hibernation support specific for ARM
4  *
5  * Derived from work on ARM hibernation support by:
6  *
7  * Ubuntu project, hibernation support for mach-dove
8  * Copyright (C) 2010 Nokia Corporation (Hiroshi Doyu)
9  * Copyright (C) 2010 Texas Instruments, Inc. (Teerth Reddy et al.)
10  *  https://lkml.org/lkml/2010/6/18/4
11  *  https://lists.linux-foundation.org/pipermail/linux-pm/2010-June/027422.html
12  *  https://patchwork.kernel.org/patch/96442/
13  *
14  * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
15  */
16 
17 #include <linux/mm.h>
18 #include <linux/suspend.h>
19 #include <asm/system_misc.h>
20 #include <asm/idmap.h>
21 #include <asm/suspend.h>
22 #include <asm/memory.h>
23 #include <asm/sections.h>
24 #include "reboot.h"
25 
pfn_is_nosave(unsigned long pfn)26 int pfn_is_nosave(unsigned long pfn)
27 {
28 	unsigned long nosave_begin_pfn = virt_to_pfn(&__nosave_begin);
29 	unsigned long nosave_end_pfn = virt_to_pfn(&__nosave_end - 1);
30 
31 	return (pfn >= nosave_begin_pfn) && (pfn <= nosave_end_pfn);
32 }
33 
save_processor_state(void)34 void notrace save_processor_state(void)
35 {
36 	WARN_ON(num_online_cpus() != 1);
37 	local_fiq_disable();
38 }
39 
restore_processor_state(void)40 void notrace restore_processor_state(void)
41 {
42 	local_fiq_enable();
43 }
44 
45 /*
46  * Snapshot kernel memory and reset the system.
47  *
48  * swsusp_save() is executed in the suspend finisher so that the CPU
49  * context pointer and memory are part of the saved image, which is
50  * required by the resume kernel image to restart execution from
51  * swsusp_arch_suspend().
52  *
53  * soft_restart is not technically needed, but is used to get success
54  * returned from cpu_suspend.
55  *
56  * When soft reboot completes, the hibernation snapshot is written out.
57  */
arch_save_image(unsigned long unused)58 static int notrace arch_save_image(unsigned long unused)
59 {
60 	int ret;
61 
62 	ret = swsusp_save();
63 	if (ret == 0)
64 		_soft_restart(virt_to_idmap(cpu_resume), false);
65 	return ret;
66 }
67 
68 /*
69  * Save the current CPU state before suspend / poweroff.
70  */
swsusp_arch_suspend(void)71 int notrace swsusp_arch_suspend(void)
72 {
73 	return cpu_suspend(0, arch_save_image);
74 }
75 
76 /*
77  * Restore page contents for physical pages that were in use during loading
78  * hibernation image.  Switch to idmap_pgd so the physical page tables
79  * are overwritten with the same contents.
80  */
arch_restore_image(void * unused)81 static void notrace arch_restore_image(void *unused)
82 {
83 	struct pbe *pbe;
84 
85 	cpu_switch_mm(idmap_pgd, &init_mm);
86 	for (pbe = restore_pblist; pbe; pbe = pbe->next)
87 		copy_page(pbe->orig_address, pbe->address);
88 
89 	_soft_restart(virt_to_idmap(cpu_resume), false);
90 }
91 
92 static u64 resume_stack[PAGE_SIZE/2/sizeof(u64)] __nosavedata;
93 
94 /*
95  * Resume from the hibernation image.
96  * Due to the kernel heap / data restore, stack contents change underneath
97  * and that would make function calls impossible; switch to a temporary
98  * stack within the nosave region to avoid that problem.
99  */
swsusp_arch_resume(void)100 int swsusp_arch_resume(void)
101 {
102 	call_with_stack(arch_restore_image, 0,
103 		resume_stack + ARRAY_SIZE(resume_stack));
104 	return 0;
105 }
106