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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cpu-hotplug.c (1612B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * Copyright (C) 2020 Western Digital Corporation or its affiliates.
      4 */
      5
      6#include <linux/kernel.h>
      7#include <linux/mm.h>
      8#include <linux/sched.h>
      9#include <linux/err.h>
     10#include <linux/irq.h>
     11#include <linux/cpu.h>
     12#include <linux/sched/hotplug.h>
     13#include <asm/irq.h>
     14#include <asm/cpu_ops.h>
     15#include <asm/numa.h>
     16#include <asm/sbi.h>
     17
     18bool cpu_has_hotplug(unsigned int cpu)
     19{
     20	if (cpu_ops[cpu]->cpu_stop)
     21		return true;
     22
     23	return false;
     24}
     25
     26/*
     27 * __cpu_disable runs on the processor to be shutdown.
     28 */
     29int __cpu_disable(void)
     30{
     31	int ret = 0;
     32	unsigned int cpu = smp_processor_id();
     33
     34	if (!cpu_ops[cpu] || !cpu_ops[cpu]->cpu_stop)
     35		return -EOPNOTSUPP;
     36
     37	if (cpu_ops[cpu]->cpu_disable)
     38		ret = cpu_ops[cpu]->cpu_disable(cpu);
     39
     40	if (ret)
     41		return ret;
     42
     43	remove_cpu_topology(cpu);
     44	numa_remove_cpu(cpu);
     45	set_cpu_online(cpu, false);
     46	irq_migrate_all_off_this_cpu();
     47
     48	return ret;
     49}
     50
     51/*
     52 * Called on the thread which is asking for a CPU to be shutdown.
     53 */
     54void __cpu_die(unsigned int cpu)
     55{
     56	int ret = 0;
     57
     58	if (!cpu_wait_death(cpu, 5)) {
     59		pr_err("CPU %u: didn't die\n", cpu);
     60		return;
     61	}
     62	pr_notice("CPU%u: off\n", cpu);
     63
     64	/* Verify from the firmware if the cpu is really stopped*/
     65	if (cpu_ops[cpu]->cpu_is_stopped)
     66		ret = cpu_ops[cpu]->cpu_is_stopped(cpu);
     67	if (ret)
     68		pr_warn("CPU%d may not have stopped: %d\n", cpu, ret);
     69}
     70
     71/*
     72 * Called from the idle thread for the CPU which has been shutdown.
     73 */
     74void arch_cpu_idle_dead(void)
     75{
     76	idle_task_exit();
     77
     78	(void)cpu_report_death();
     79
     80	cpu_ops[smp_processor_id()]->cpu_stop();
     81	/* It should never reach here */
     82	BUG();
     83}