1 /* 2 * linux/kernel/irq/handle.c 3 * 4 * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar 5 * Copyright (C) 2005-2006, Thomas Gleixner, Russell King 6 * 7 * This file contains the core interrupt handling code. 8 * 9 * Detailed information is available in Documentation/DocBook/genericirq 10 * 11 */ 12 13 #include <linux/irq.h> 14 #include <linux/random.h> 15 #include <linux/sched.h> 16 #include <linux/interrupt.h> 17 #include <linux/kernel_stat.h> 18 19 #include <trace/events/irq.h> 20 21 #include "internals.h" 22 23 /** 24 * handle_bad_irq - handle spurious and unhandled irqs 25 * @irq: the interrupt number 26 * @desc: description of the interrupt 27 * 28 * Handles spurious and unhandled IRQ's. It also prints a debugmessage. 29 */ 30 void handle_bad_irq(unsigned int irq, struct irq_desc *desc) 31 { 32 print_irq_desc(irq, desc); 33 kstat_incr_irqs_this_cpu(irq, desc); 34 ack_bad_irq(irq); 35 } 36 37 /* 38 * Special, empty irq handler: 39 */ 40 irqreturn_t no_action(int cpl, void *dev_id) 41 { 42 return IRQ_NONE; 43 } 44 45 static void warn_no_thread(unsigned int irq, struct irqaction *action) 46 { 47 if (test_and_set_bit(IRQTF_WARNED, &action->thread_flags)) 48 return; 49 50 printk(KERN_WARNING "IRQ %d device %s returned IRQ_WAKE_THREAD " 51 "but no thread function available.", irq, action->name); 52 } 53 54 irqreturn_t 55 handle_irq_event_percpu(struct irq_desc *desc, struct irqaction *action) 56 { 57 irqreturn_t ret, retval = IRQ_NONE; 58 unsigned int status = 0, irq = desc->irq_data.irq; 59 60 do { 61 trace_irq_handler_entry(irq, action); 62 ret = action->handler(irq, action->dev_id); 63 trace_irq_handler_exit(irq, action, ret); 64 65 if (WARN_ON_ONCE(!irqs_disabled())) 66 local_irq_disable(); 67 68 switch (ret) { 69 case IRQ_WAKE_THREAD: 70 /* 71 * Set result to handled so the spurious check 72 * does not trigger. 73 */ 74 ret = IRQ_HANDLED; 75 76 /* 77 * Catch drivers which return WAKE_THREAD but 78 * did not set up a thread function 79 */ 80 if (unlikely(!action->thread_fn)) { 81 warn_no_thread(irq, action); 82 break; 83 } 84 85 /* 86 * Wake up the handler thread for this 87 * action. In case the thread crashed and was 88 * killed we just pretend that we handled the 89 * interrupt. The hardirq handler above has 90 * disabled the device interrupt, so no irq 91 * storm is lurking. 92 */ 93 if (likely(!test_bit(IRQTF_DIED, 94 &action->thread_flags))) { 95 set_bit(IRQTF_RUNTHREAD, &action->thread_flags); 96 wake_up_process(action->thread); 97 } 98 99 /* Fall through to add to randomness */ 100 case IRQ_HANDLED: 101 status |= action->flags; 102 break; 103 104 default: 105 break; 106 } 107 108 retval |= ret; 109 action = action->next; 110 } while (action); 111 112 if (status & IRQF_SAMPLE_RANDOM) 113 add_interrupt_randomness(irq); 114 115 if (!noirqdebug) 116 note_interrupt(irq, desc, ret); 117 return retval; 118 } 119 120 irqreturn_t handle_irq_event(struct irq_desc *desc) 121 { 122 struct irqaction *action = desc->action; 123 irqreturn_t ret; 124 125 desc->status &= ~IRQ_PENDING; 126 desc->status |= IRQ_INPROGRESS; 127 raw_spin_unlock(&desc->lock); 128 129 ret = handle_irq_event_percpu(desc, action); 130 131 raw_spin_lock(&desc->lock); 132 desc->status &= ~IRQ_INPROGRESS; 133 return ret; 134 } 135 136 /** 137 * handle_IRQ_event - irq action chain handler 138 * @irq: the interrupt number 139 * @action: the interrupt action chain for this irq 140 * 141 * Handles the action chain of an irq event 142 */ 143 irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action) 144 { 145 return handle_irq_event_percpu(irq_to_desc(irq), action); 146 } 147