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}