root/arch/arm/kernel/hibernate.c

DEFINITIONS

1. pfn_is_nosave
2. save_processor_state
3. restore_processor_state
4. arch_save_image
5. swsusp_arch_suspend
6. arch_restore_image
7. swsusp_arch_resume

   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 
  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 }