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git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - kernel/irq/handle.c
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(unsigned int irq
, struct irq_desc
*desc
)
32 print_irq_desc(irq
, desc
);
33 kstat_incr_irqs_this_cpu(irq
, desc
);
38 * Special, empty irq handler:
40 irqreturn_t
no_action(int cpl
, void *dev_id
)
45 static void warn_no_thread(unsigned int irq
, struct irqaction
*action
)
47 if (test_and_set_bit(IRQTF_WARNED
, &action
->thread_flags
))
50 printk(KERN_WARNING
"IRQ %d device %s returned IRQ_WAKE_THREAD "
51 "but no thread function available.", irq
, action
->name
);
54 static void irq_wake_thread(struct irq_desc
*desc
, struct irqaction
*action
)
57 * In case the thread crashed and was killed we just pretend that
58 * we handled the interrupt. The hardirq handler has disabled the
59 * device interrupt, so no irq storm is lurking.
61 if (action
->thread
->flags
& PF_EXITING
)
65 * Wake up the handler thread for this action. If the
66 * RUNTHREAD bit is already set, nothing to do.
68 if (test_and_set_bit(IRQTF_RUNTHREAD
, &action
->thread_flags
))
72 * It's safe to OR the mask lockless here. We have only two
73 * places which write to threads_oneshot: This code and the
76 * This code is the hard irq context and can never run on two
77 * cpus in parallel. If it ever does we have more serious
78 * problems than this bitmask.
80 * The irq threads of this irq which clear their "running" bit
81 * in threads_oneshot are serialized via desc->lock against
82 * each other and they are serialized against this code by
87 * spin_lock(desc->lock);
88 * desc->state |= IRQS_INPROGRESS;
89 * spin_unlock(desc->lock);
90 * set_bit(IRQTF_RUNTHREAD, &action->thread_flags);
91 * desc->threads_oneshot |= mask;
92 * spin_lock(desc->lock);
93 * desc->state &= ~IRQS_INPROGRESS;
94 * spin_unlock(desc->lock);
99 * spin_lock(desc->lock);
100 * if (desc->state & IRQS_INPROGRESS) {
101 * spin_unlock(desc->lock);
102 * while(desc->state & IRQS_INPROGRESS)
106 * if (!test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
107 * desc->threads_oneshot &= ~mask;
108 * spin_unlock(desc->lock);
110 * So either the thread waits for us to clear IRQS_INPROGRESS
111 * or we are waiting in the flow handler for desc->lock to be
112 * released before we reach this point. The thread also checks
113 * IRQTF_RUNTHREAD under desc->lock. If set it leaves
114 * threads_oneshot untouched and runs the thread another time.
116 desc
->threads_oneshot
|= action
->thread_mask
;
119 * We increment the threads_active counter in case we wake up
120 * the irq thread. The irq thread decrements the counter when
121 * it returns from the handler or in the exit path and wakes
122 * up waiters which are stuck in synchronize_irq() when the
123 * active count becomes zero. synchronize_irq() is serialized
124 * against this code (hard irq handler) via IRQS_INPROGRESS
125 * like the finalize_oneshot() code. See comment above.
127 atomic_inc(&desc
->threads_active
);
129 wake_up_process(action
->thread
);
133 handle_irq_event_percpu(struct irq_desc
*desc
, struct irqaction
*action
)
135 irqreturn_t retval
= IRQ_NONE
;
136 unsigned int flags
= 0, irq
= desc
->irq_data
.irq
;
141 trace_irq_handler_entry(irq
, action
);
142 res
= action
->handler(irq
, action
->dev_id
);
143 trace_irq_handler_exit(irq
, action
, res
);
145 if (WARN_ONCE(!irqs_disabled(),"irq %u handler %pF enabled interrupts\n",
146 irq
, action
->handler
))
150 case IRQ_WAKE_THREAD
:
152 * Catch drivers which return WAKE_THREAD but
153 * did not set up a thread function
155 if (unlikely(!action
->thread_fn
)) {
156 warn_no_thread(irq
, action
);
160 irq_wake_thread(desc
, action
);
162 /* Fall through to add to randomness */
164 flags
|= action
->flags
;
172 action
= action
->next
;
175 add_interrupt_randomness(irq
, flags
);
178 note_interrupt(irq
, desc
, retval
);
182 irqreturn_t
handle_irq_event(struct irq_desc
*desc
)
184 struct irqaction
*action
= desc
->action
;
187 desc
->istate
&= ~IRQS_PENDING
;
188 irqd_set(&desc
->irq_data
, IRQD_IRQ_INPROGRESS
);
189 raw_spin_unlock(&desc
->lock
);
191 ret
= handle_irq_event_percpu(desc
, action
);
193 raw_spin_lock(&desc
->lock
);
194 irqd_clear(&desc
->irq_data
, IRQD_IRQ_INPROGRESS
);