LXR linux/arch/arm64/kernel/irq.c

   1/*
   2 * Based on arch/arm/kernel/irq.c
   3 *
   4 * Copyright (C) 1992 Linus Torvalds
   5 * Modifications for ARM processor Copyright (C) 1995-2000 Russell King.
   6 * Support for Dynamic Tick Timer Copyright (C) 2004-2005 Nokia Corporation.
   7 * Dynamic Tick Timer written by Tony Lindgren <tony@atomide.com> and
   8 * Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>.
   9 * Copyright (C) 2012 ARM Ltd.
  10 *
  11 * This program is free software; you can redistribute it and/or modify
  12 * it under the terms of the GNU General Public License version 2 as
  13 * published by the Free Software Foundation.
  14 *
  15 * This program is distributed in the hope that it will be useful,
  16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 * GNU General Public License for more details.
  19 *
  20 * You should have received a copy of the GNU General Public License
  21 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  22 */
  23
  24#include <linux/kernel_stat.h>
  25#include <linux/irq.h>
  26#include <linux/smp.h>
  27#include <linux/init.h>
  28#include <linux/irqchip.h>
  29#include <linux/seq_file.h>
  30#include <linux/ratelimit.h>
  31
  32unsigned long irq_err_count;
  33
  34int arch_show_interrupts(struct seq_file *p, int prec)
  35{
  36#ifdef CONFIG_SMP
  37        show_ipi_list(p, prec);
  38#endif
  39        seq_printf(p, "%*s: %10lu\n", prec, "Err", irq_err_count);
  40        return 0;
  41}
  42
  43/*
  44 * handle_IRQ handles all hardware IRQ's.  Decoded IRQs should
  45 * not come via this function.  Instead, they should provide their
  46 * own 'handler'.  Used by platform code implementing C-based 1st
  47 * level decoding.
  48 */
  49void handle_IRQ(unsigned int irq, struct pt_regs *regs)
  50{
  51        struct pt_regs *old_regs = set_irq_regs(regs);
  52
  53        irq_enter();
  54
  55        /*
  56         * Some hardware gives randomly wrong interrupts.  Rather
  57         * than crashing, do something sensible.
  58         */
  59        if (unlikely(irq >= nr_irqs)) {
  60                pr_warn_ratelimited("Bad IRQ%u\n", irq);
  61                ack_bad_irq(irq);
  62        } else {
  63                generic_handle_irq(irq);
  64        }
  65
  66        irq_exit();
  67        set_irq_regs(old_regs);
  68}
  69
  70void __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
  71{
  72        if (handle_arch_irq)
  73                return;
  74
  75        handle_arch_irq = handle_irq;
  76}
  77
  78void __init init_IRQ(void)
  79{
  80        irqchip_init();
  81        if (!handle_arch_irq)
  82                panic("No interrupt controller found.");
  83}
  84
  85#ifdef CONFIG_HOTPLUG_CPU
  86static bool migrate_one_irq(struct irq_desc *desc)
  87{
  88        struct irq_data *d = irq_desc_get_irq_data(desc);
  89        const struct cpumask *affinity = d->affinity;
  90        struct irq_chip *c;
  91        bool ret = false;
  92
  93        /*
  94         * If this is a per-CPU interrupt, or the affinity does not
  95         * include this CPU, then we have nothing to do.
  96         */
  97        if (irqd_is_per_cpu(d) || !cpumask_test_cpu(smp_processor_id(), affinity))
  98                return false;
  99
 100        if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
 101                affinity = cpu_online_mask;
 102                ret = true;
 103        }
 104
 105        c = irq_data_get_irq_chip(d);
 106        if (!c->irq_set_affinity)
 107                pr_debug("IRQ%u: unable to set affinity\n", d->irq);
 108        else if (c->irq_set_affinity(d, affinity, true) == IRQ_SET_MASK_OK && ret)
 109                cpumask_copy(d->affinity, affinity);
 110
 111        return ret;
 112}
 113
 114/*
 115 * The current CPU has been marked offline.  Migrate IRQs off this CPU.
 116 * If the affinity settings do not allow other CPUs, force them onto any
 117 * available CPU.
 118 *
 119 * Note: we must iterate over all IRQs, whether they have an attached
 120 * action structure or not, as we need to get chained interrupts too.
 121 */
 122void migrate_irqs(void)
 123{
 124        unsigned int i;
 125        struct irq_desc *desc;
 126        unsigned long flags;
 127
 128        local_irq_save(flags);
 129
 130        for_each_irq_desc(i, desc) {
 131                bool affinity_broken;
 132
 133                raw_spin_lock(&desc->lock);
 134                affinity_broken = migrate_one_irq(desc);
 135                raw_spin_unlock(&desc->lock);
 136
 137                if (affinity_broken)
 138                        pr_warn_ratelimited("IRQ%u no longer affine to CPU%u\n",
 139                                            i, smp_processor_id());
 140        }
 141
 142        local_irq_restore(flags);
 143}
 144#endif /* CONFIG_HOTPLUG_CPU */
 145