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| 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 | /** |
| 55 | * handle_IRQ_event - irq action chain handler |
| 56 | * @irq: the interrupt number |
| 57 | * @action: the interrupt action chain for this irq |
| 58 | * |
| 59 | * Handles the action chain of an irq event |
| 60 | */ |
| 61 | irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action) |
| 62 | { |
| 63 | irqreturn_t ret, retval = IRQ_NONE; |
| 64 | unsigned int status = 0; |
| 65 | |
| 66 | do { |
| 67 | trace_irq_handler_entry(irq, action); |
| 68 | ret = action->handler(irq, action->dev_id); |
| 69 | trace_irq_handler_exit(irq, action, ret); |
| 70 | |
| 71 | switch (ret) { |
| 72 | case IRQ_WAKE_THREAD: |
| 73 | /* |
| 74 | * Set result to handled so the spurious check |
| 75 | * does not trigger. |
| 76 | */ |
| 77 | ret = IRQ_HANDLED; |
| 78 | |
| 79 | /* |
| 80 | * Catch drivers which return WAKE_THREAD but |
| 81 | * did not set up a thread function |
| 82 | */ |
| 83 | if (unlikely(!action->thread_fn)) { |
| 84 | warn_no_thread(irq, action); |
| 85 | break; |
| 86 | } |
| 87 | |
| 88 | /* |
| 89 | * Wake up the handler thread for this |
| 90 | * action. In case the thread crashed and was |
| 91 | * killed we just pretend that we handled the |
| 92 | * interrupt. The hardirq handler above has |
| 93 | * disabled the device interrupt, so no irq |
| 94 | * storm is lurking. |
| 95 | */ |
| 96 | if (likely(!test_bit(IRQTF_DIED, |
| 97 | &action->thread_flags))) { |
| 98 | set_bit(IRQTF_RUNTHREAD, &action->thread_flags); |
| 99 | wake_up_process(action->thread); |
| 100 | } |
| 101 | |
| 102 | /* Fall through to add to randomness */ |
| 103 | case IRQ_HANDLED: |
| 104 | status |= action->flags; |
| 105 | break; |
| 106 | |
| 107 | default: |
| 108 | break; |
| 109 | } |
| 110 | |
| 111 | retval |= ret; |
| 112 | action = action->next; |
| 113 | } while (action); |
| 114 | |
| 115 | if (status & IRQF_SAMPLE_RANDOM) |
| 116 | add_interrupt_randomness(irq); |
| 117 | local_irq_disable(); |
| 118 | |
| 119 | return retval; |
| 120 | } |
| 121 |
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