1/*
 2 * Generic cpu hotunplug interrupt migration code copied from the
 3 * arch/arm implementation
 4 *
 5 * Copyright (C) Russell King
 6 *
 7 * This program is free software; you can redistribute it and/or modify
 8 * it under the terms of the GNU General Public License version 2 as
 9 * published by the Free Software Foundation.
10 */
11#include <linux/interrupt.h>
12#include <linux/ratelimit.h>
13#include <linux/irq.h>
14
15#include "internals.h"
16
17static bool migrate_one_irq(struct irq_desc *desc)
18{
19	struct irq_data *d = irq_desc_get_irq_data(desc);
20	const struct cpumask *affinity = d->common->affinity;
21	struct irq_chip *c;
22	bool ret = false;
23
24	/*
25	 * If this is a per-CPU interrupt, or the affinity does not
26	 * include this CPU, then we have nothing to do.
27	 */
28	if (irqd_is_per_cpu(d) ||
29	    !cpumask_test_cpu(smp_processor_id(), affinity))
30		return false;
31
32	if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
33		affinity = cpu_online_mask;
34		ret = true;
35	}
36
37	c = irq_data_get_irq_chip(d);
38	if (!c->irq_set_affinity) {
39		pr_debug("IRQ%u: unable to set affinity\n", d->irq);
40	} else {
41		int r = irq_do_set_affinity(d, affinity, false);
42		if (r)
43			pr_warn_ratelimited("IRQ%u: set affinity failed(%d).\n",
44					    d->irq, r);
45	}
46
47	return ret;
48}
49
50/**
51 * irq_migrate_all_off_this_cpu - Migrate irqs away from offline cpu
52 *
53 * The current CPU has been marked offline.  Migrate IRQs off this CPU.
54 * If the affinity settings do not allow other CPUs, force them onto any
55 * available CPU.
56 *
57 * Note: we must iterate over all IRQs, whether they have an attached
58 * action structure or not, as we need to get chained interrupts too.
59 */
60void irq_migrate_all_off_this_cpu(void)
61{
62	unsigned int irq;
63	struct irq_desc *desc;
64	unsigned long flags;
65
66	local_irq_save(flags);
67
68	for_each_active_irq(irq) {
69		bool affinity_broken;
70
71		desc = irq_to_desc(irq);
72		raw_spin_lock(&desc->lock);
73		affinity_broken = migrate_one_irq(desc);
74		raw_spin_unlock(&desc->lock);
75
76		if (affinity_broken)
77			pr_warn_ratelimited("IRQ%u no longer affine to CPU%u\n",
78					    irq, smp_processor_id());
79	}
80
81	local_irq_restore(flags);
82}