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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pm.c (2006B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 * Copyright (C) 2014 Imagination Technologies Ltd.
      4 *
      5 * CPU PM notifiers for saving/restoring general CPU state.
      6 */
      7
      8#include <linux/cpu_pm.h>
      9#include <linux/init.h>
     10
     11#include <asm/dsp.h>
     12#include <asm/fpu.h>
     13#include <asm/mmu_context.h>
     14#include <asm/pm.h>
     15#include <asm/watch.h>
     16
     17/* Used by PM helper macros in asm/pm.h */
     18struct mips_static_suspend_state mips_static_suspend_state;
     19
     20/**
     21 * mips_cpu_save() - Save general CPU state.
     22 * Ensures that general CPU context is saved, notably FPU and DSP.
     23 */
     24static int mips_cpu_save(void)
     25{
     26	/* Save FPU state */
     27	lose_fpu(1);
     28
     29	/* Save DSP state */
     30	save_dsp(current);
     31
     32	return 0;
     33}
     34
     35/**
     36 * mips_cpu_restore() - Restore general CPU state.
     37 * Restores important CPU context.
     38 */
     39static void mips_cpu_restore(void)
     40{
     41	unsigned int cpu = smp_processor_id();
     42
     43	/* Restore ASID */
     44	if (current->mm)
     45		write_c0_entryhi(cpu_asid(cpu, current->mm));
     46
     47	/* Restore DSP state */
     48	restore_dsp(current);
     49
     50	/* Restore UserLocal */
     51	if (cpu_has_userlocal)
     52		write_c0_userlocal(current_thread_info()->tp_value);
     53
     54	/* Restore watch registers */
     55	__restore_watch(current);
     56}
     57
     58/**
     59 * mips_pm_notifier() - Notifier for preserving general CPU context.
     60 * @self:	Notifier block.
     61 * @cmd:	CPU PM event.
     62 * @v:		Private data (unused).
     63 *
     64 * This is called when a CPU power management event occurs, and is used to
     65 * ensure that important CPU context is preserved across a CPU power down.
     66 */
     67static int mips_pm_notifier(struct notifier_block *self, unsigned long cmd,
     68			    void *v)
     69{
     70	int ret;
     71
     72	switch (cmd) {
     73	case CPU_PM_ENTER:
     74		ret = mips_cpu_save();
     75		if (ret)
     76			return NOTIFY_STOP;
     77		break;
     78	case CPU_PM_ENTER_FAILED:
     79	case CPU_PM_EXIT:
     80		mips_cpu_restore();
     81		break;
     82	}
     83
     84	return NOTIFY_OK;
     85}
     86
     87static struct notifier_block mips_pm_notifier_block = {
     88	.notifier_call = mips_pm_notifier,
     89};
     90
     91static int __init mips_pm_init(void)
     92{
     93	return cpu_pm_register_notifier(&mips_pm_notifier_block);
     94}
     95arch_initcall(mips_pm_init);