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
  32 unsigned long irq_err_count;
  33
  34 int 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 void (*handle_arch_irq)(struct pt_regs *) = NULL;
  44
  45 void __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
  46 {
  47         if (handle_arch_irq)
  48                 return;
  49
  50         handle_arch_irq = handle_irq;
  51 }
  52
  53 void __init init_IRQ(void)
  54 {
  55         irqchip_init();
  56         if (!handle_arch_irq)
  57                 panic("No interrupt controller found.");
  58 }
  59
  60 #ifdef CONFIG_HOTPLUG_CPU
  61 static bool migrate_one_irq(struct irq_desc *desc)
  62 {
  63         struct irq_data *d = irq_desc_get_irq_data(desc);
  64         const struct cpumask *affinity = d->affinity;
  65         struct irq_chip *c;
  66         bool ret = false;
  67
  68         /*
  69          * If this is a per-CPU interrupt, or the affinity does not
  70          * include this CPU, then we have nothing to do.
  71          */
  72         if (irqd_is_per_cpu(d) || !cpumask_test_cpu(smp_processor_id(), affinity))
  73                 return false;
  74
  75         if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
  76                 affinity = cpu_online_mask;
  77                 ret = true;
  78         }
  79
  80         c = irq_data_get_irq_chip(d);
  81         if (!c->irq_set_affinity)
  82                 pr_debug("IRQ%u: unable to set affinity\n", d->irq);
  83         else if (c->irq_set_affinity(d, affinity, false) == IRQ_SET_MASK_OK && ret)
  84                 cpumask_copy(d->affinity, affinity);
  85
  86         return ret;
  87 }
  88
  89 /*
  90  * The current CPU has been marked offline.  Migrate IRQs off this CPU.
  91  * If the affinity settings do not allow other CPUs, force them onto any
  92  * available CPU.
  93  *
  94  * Note: we must iterate over all IRQs, whether they have an attached
  95  * action structure or not, as we need to get chained interrupts too.
  96  */
  97 void migrate_irqs(void)
  98 {
  99         unsigned int i;
 100         struct irq_desc *desc;
 101         unsigned long flags;
 102
 103         local_irq_save(flags);
 104
 105         for_each_irq_desc(i, desc) {
 106                 bool affinity_broken;
 107
 108                 raw_spin_lock(&desc->lock);
 109                 affinity_broken = migrate_one_irq(desc);
 110                 raw_spin_unlock(&desc->lock);
 111
 112                 if (affinity_broken)
 113                         pr_warn_ratelimited("IRQ%u no longer affine to CPU%u\n",
 114                                             i, smp_processor_id());
 115         }
 116
 117         local_irq_restore(flags);
 118 }
 119 #endif /* CONFIG_HOTPLUG_CPU */