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 /*
  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  */
  49 void 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
  70 void __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
  78 void __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
  86 static 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                 ret = true;
 102
 103         /*
 104          * when using forced irq_set_affinity we must ensure that the cpu
 105          * being offlined is not present in the affinity mask, it may be
 106          * selected as the target CPU otherwise
 107          */
 108         affinity = cpu_online_mask;
 109         c = irq_data_get_irq_chip(d);
 110         if (!c->irq_set_affinity)
 111                 pr_debug("IRQ%u: unable to set affinity\n", d->irq);
 112         else if (c->irq_set_affinity(d, affinity, true) == IRQ_SET_MASK_OK && ret)
 113                 cpumask_copy(d->affinity, affinity);
 114
 115         return ret;
 116 }
 117
 118 /*
 119  * The current CPU has been marked offline.  Migrate IRQs off this CPU.
 120  * If the affinity settings do not allow other CPUs, force them onto any
 121  * available CPU.
 122  *
 123  * Note: we must iterate over all IRQs, whether they have an attached
 124  * action structure or not, as we need to get chained interrupts too.
 125  */
 126 void migrate_irqs(void)
 127 {
 128         unsigned int i;
 129         struct irq_desc *desc;
 130         unsigned long flags;
 131
 132         local_irq_save(flags);
 133
 134         for_each_irq_desc(i, desc) {
 135                 bool affinity_broken;
 136
 137                 raw_spin_lock(&desc->lock);
 138                 affinity_broken = migrate_one_irq(desc);
 139                 raw_spin_unlock(&desc->lock);
 140
 141                 if (affinity_broken)
 142                         pr_warn_ratelimited("IRQ%u no longer affine to CPU%u\n",
 143                                             i, smp_processor_id());
 144         }
 145
 146         local_irq_restore(flags);
 147 }
 148 #endif /* CONFIG_HOTPLUG_CPU */