summaryrefslogtreecommitdiff
path: root/arch/riscv/kernel/cpu-hotplug.c
blob: 28b58fc5ad1996112c67b7f6030f9ba81a26b388 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2020 Western Digital Corporation or its affiliates.
 */

#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/err.h>
#include <linux/irq.h>
#include <linux/cpuhotplug.h>
#include <linux/cpu.h>
#include <linux/sched/hotplug.h>
#include <asm/irq.h>
#include <asm/cpu_ops.h>
#include <asm/numa.h>
#include <asm/smp.h>

bool cpu_has_hotplug(unsigned int cpu)
{
	if (cpu_ops->cpu_stop)
		return true;

	return false;
}

/*
 * __cpu_disable runs on the processor to be shutdown.
 */
int __cpu_disable(void)
{
	unsigned int cpu = smp_processor_id();

	if (!cpu_ops->cpu_stop)
		return -EOPNOTSUPP;

	remove_cpu_topology(cpu);
	numa_remove_cpu(cpu);
	set_cpu_online(cpu, false);
	riscv_ipi_disable();
	irq_migrate_all_off_this_cpu();

	return 0;
}

#ifdef CONFIG_HOTPLUG_CPU
/*
 * Called on the thread which is asking for a CPU to be shutdown, if the
 * CPU reported dead to the hotplug core.
 */
void arch_cpuhp_cleanup_dead_cpu(unsigned int cpu)
{
	int ret = 0;

	pr_notice("CPU%u: off\n", cpu);

	/* Verify from the firmware if the cpu is really stopped*/
	if (cpu_ops->cpu_is_stopped)
		ret = cpu_ops->cpu_is_stopped(cpu);
	if (ret)
		pr_warn("CPU%d may not have stopped: %d\n", cpu, ret);
}

/*
 * Called from the idle thread for the CPU which has been shutdown.
 */
void __noreturn arch_cpu_idle_dead(void)
{
	idle_task_exit();

	cpuhp_ap_report_dead();

	cpu_ops->cpu_stop();
	/* It should never reach here */
	BUG();
}
#endif