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

   1/*
   2 * Hibernation support specific for ARM
   3 *
   4 * Derived from work on ARM hibernation support by:
   5 *
   6 * Ubuntu project, hibernation support for mach-dove
   7 * Copyright (C) 2010 Nokia Corporation (Hiroshi Doyu)
   8 * Copyright (C) 2010 Texas Instruments, Inc. (Teerth Reddy et al.)
   9 *  https://lkml.org/lkml/2010/6/18/4
  10 *  https://lists.linux-foundation.org/pipermail/linux-pm/2010-June/027422.html
  11 *  https://patchwork.kernel.org/patch/96442/
  12 *
  13 * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
  14 *
  15 * License terms: GNU General Public License (GPL) version 2
  16 */
  17
  18#include <linux/mm.h>
  19#include <linux/suspend.h>
  20#include <asm/system_misc.h>
  21#include <asm/idmap.h>
  22#include <asm/suspend.h>
  23#include <asm/memory.h>
  24#include <asm/sections.h>
  25#include "reboot.h"
  26
  27int pfn_is_nosave(unsigned long pfn)
  28{
  29        unsigned long nosave_begin_pfn = virt_to_pfn(&__nosave_begin);
  30        unsigned long nosave_end_pfn = virt_to_pfn(&__nosave_end - 1);
  31
  32        return (pfn >= nosave_begin_pfn) && (pfn <= nosave_end_pfn);
  33}
  34
  35void notrace save_processor_state(void)
  36{
  37        WARN_ON(num_online_cpus() != 1);
  38        local_fiq_disable();
  39}
  40
  41void notrace restore_processor_state(void)
  42{
  43        local_fiq_enable();
  44}
  45
  46/*
  47 * Snapshot kernel memory and reset the system.
  48 *
  49 * swsusp_save() is executed in the suspend finisher so that the CPU
  50 * context pointer and memory are part of the saved image, which is
  51 * required by the resume kernel image to restart execution from
  52 * swsusp_arch_suspend().
  53 *
  54 * soft_restart is not technically needed, but is used to get success
  55 * returned from cpu_suspend.
  56 *
  57 * When soft reboot completes, the hibernation snapshot is written out.
  58 */
  59static int notrace arch_save_image(unsigned long unused)
  60{
  61        int ret;
  62
  63        ret = swsusp_save();
  64        if (ret == 0)
  65                _soft_restart(virt_to_idmap(cpu_resume), false);
  66        return ret;
  67}
  68
  69/*
  70 * Save the current CPU state before suspend / poweroff.
  71 */
  72int notrace swsusp_arch_suspend(void)
  73{
  74        return cpu_suspend(0, arch_save_image);
  75}
  76
  77/*
  78 * Restore page contents for physical pages that were in use during loading
  79 * hibernation image.  Switch to idmap_pgd so the physical page tables
  80 * are overwritten with the same contents.
  81 */
  82static void notrace arch_restore_image(void *unused)
  83{
  84        struct pbe *pbe;
  85
  86        cpu_switch_mm(idmap_pgd, &init_mm);
  87        for (pbe = restore_pblist; pbe; pbe = pbe->next)
  88                copy_page(pbe->orig_address, pbe->address);
  89
  90        _soft_restart(virt_to_idmap(cpu_resume), false);
  91}
  92
  93static u64 resume_stack[PAGE_SIZE/2/sizeof(u64)] __nosavedata;
  94
  95/*
  96 * Resume from the hibernation image.
  97 * Due to the kernel heap / data restore, stack contents change underneath
  98 * and that would make function calls impossible; switch to a temporary
  99 * stack within the nosave region to avoid that problem.
 100 */
 101int swsusp_arch_resume(void)
 102{
 103        call_with_stack(arch_restore_image, 0,
 104                resume_stack + ARRAY_SIZE(resume_stack));
 105        return 0;
 106}
 107