2 * linux/kernel/irq/handle.c
4 * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
5 * Copyright (C) 2005-2006, Thomas Gleixner, Russell King
7 * This file contains the core interrupt handling code.
9 * Detailed information is available in Documentation/DocBook/genericirq
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>
19 #include <trace/events/irq.h>
21 #include "internals.h"
24 * handle_bad_irq - handle spurious and unhandled irqs
25 * @irq: the interrupt number
26 * @desc: description of the interrupt
28 * Handles spurious and unhandled IRQ's. It also prints a debugmessage.
30 void handle_bad_irq(struct irq_desc *desc)
32 unsigned int irq = irq_desc_get_irq(desc);
34 print_irq_desc(irq, desc);
35 kstat_incr_irqs_this_cpu(desc);
38 EXPORT_SYMBOL_GPL(handle_bad_irq);
41 * Special, empty irq handler:
43 irqreturn_t no_action(int cpl, void *dev_id)
47 EXPORT_SYMBOL_GPL(no_action);
49 static void warn_no_thread(unsigned int irq, struct irqaction *action)
51 if (test_and_set_bit(IRQTF_WARNED, &action->thread_flags))
54 printk(KERN_WARNING "IRQ %d device %s returned IRQ_WAKE_THREAD "
55 "but no thread function available.", irq, action->name);
58 void __irq_wake_thread(struct irq_desc *desc, struct irqaction *action)
61 * In case the thread crashed and was killed we just pretend that
62 * we handled the interrupt. The hardirq handler has disabled the
63 * device interrupt, so no irq storm is lurking.
65 if (action->thread->flags & PF_EXITING)
69 * Wake up the handler thread for this action. If the
70 * RUNTHREAD bit is already set, nothing to do.
72 if (test_and_set_bit(IRQTF_RUNTHREAD, &action->thread_flags))
76 * It's safe to OR the mask lockless here. We have only two
77 * places which write to threads_oneshot: This code and the
80 * This code is the hard irq context and can never run on two
81 * cpus in parallel. If it ever does we have more serious
82 * problems than this bitmask.
84 * The irq threads of this irq which clear their "running" bit
85 * in threads_oneshot are serialized via desc->lock against
86 * each other and they are serialized against this code by
91 * spin_lock(desc->lock);
92 * desc->state |= IRQS_INPROGRESS;
93 * spin_unlock(desc->lock);
94 * set_bit(IRQTF_RUNTHREAD, &action->thread_flags);
95 * desc->threads_oneshot |= mask;
96 * spin_lock(desc->lock);
97 * desc->state &= ~IRQS_INPROGRESS;
98 * spin_unlock(desc->lock);
103 * spin_lock(desc->lock);
104 * if (desc->state & IRQS_INPROGRESS) {
105 * spin_unlock(desc->lock);
106 * while(desc->state & IRQS_INPROGRESS)
110 * if (!test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
111 * desc->threads_oneshot &= ~mask;
112 * spin_unlock(desc->lock);
114 * So either the thread waits for us to clear IRQS_INPROGRESS
115 * or we are waiting in the flow handler for desc->lock to be
116 * released before we reach this point. The thread also checks
117 * IRQTF_RUNTHREAD under desc->lock. If set it leaves
118 * threads_oneshot untouched and runs the thread another time.
120 desc->threads_oneshot |= action->thread_mask;
123 * We increment the threads_active counter in case we wake up
124 * the irq thread. The irq thread decrements the counter when
125 * it returns from the handler or in the exit path and wakes
126 * up waiters which are stuck in synchronize_irq() when the
127 * active count becomes zero. synchronize_irq() is serialized
128 * against this code (hard irq handler) via IRQS_INPROGRESS
129 * like the finalize_oneshot() code. See comment above.
131 atomic_inc(&desc->threads_active);
133 wake_up_process(action->thread);
137 handle_irq_event_percpu(struct irq_desc *desc, struct irqaction *action)
139 irqreturn_t retval = IRQ_NONE;
140 unsigned int flags = 0, irq = desc->irq_data.irq;
145 trace_irq_handler_entry(irq, action);
146 res = action->handler(irq, action->dev_id);
147 trace_irq_handler_exit(irq, action, res);
149 if (WARN_ONCE(!irqs_disabled(),"irq %u handler %pF enabled interrupts\n",
150 irq, action->handler))
154 case IRQ_WAKE_THREAD:
156 * Catch drivers which return WAKE_THREAD but
157 * did not set up a thread function
159 if (unlikely(!action->thread_fn)) {
160 warn_no_thread(irq, action);
164 __irq_wake_thread(desc, action);
166 /* Fall through to add to randomness */
168 flags |= action->flags;
176 action = action->next;
179 add_interrupt_randomness(irq, flags);
182 note_interrupt(desc, retval);
186 irqreturn_t handle_irq_event(struct irq_desc *desc)
188 struct irqaction *action = desc->action;
191 desc->istate &= ~IRQS_PENDING;
192 irqd_set(&desc->irq_data, IRQD_IRQ_INPROGRESS);
193 raw_spin_unlock(&desc->lock);
195 ret = handle_irq_event_percpu(desc, action);
197 raw_spin_lock(&desc->lock);
198 irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);