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 */ 149