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
  27 int 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
  35 void notrace save_processor_state(void)
  36 {
  37         WARN_ON(num_online_cpus() != 1);
  38         local_fiq_disable();
  39 }
  40
  41 void 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  */
  59 static 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  */
  72 int 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  */
  82 static 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
  93 static 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  */
 101 int swsusp_arch_resume(void)
 102 {
 103         call_with_stack(arch_restore_image, 0,
 104                 resume_stack + ARRAY_SIZE(resume_stack));
 105         return 0;
 106 }