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/page.h>
23 #include <asm/sections.h>
24 #include "reboot.h"
25
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
34 void notrace save_processor_state(void)
35 {
36 WARN_ON(num_online_cpus() != 1);
37 local_fiq_disable();
38 }
39
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 */
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 */
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 */
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 */
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
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