cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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hibernate.c (2829B)

      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}