LXR linux/arch/arm/kernel/hibernate.c

   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
  26int 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
  34void notrace save_processor_state(void)
  35{
  36        WARN_ON(num_online_cpus() != 1);
  37        local_fiq_disable();
  38}
  39
  40void 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 */
  58static 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 */
  71int 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 */
  81static 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
  92static 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 */
 100int 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