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1da177e4 LT |
1 | /* |
2 | * linux/kernel/irq/handle.c | |
3 | * | |
a34db9b2 IM |
4 | * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar |
5 | * Copyright (C) 2005-2006, Thomas Gleixner, Russell King | |
1da177e4 LT |
6 | * |
7 | * This file contains the core interrupt handling code. | |
a34db9b2 IM |
8 | * |
9 | * Detailed information is available in Documentation/DocBook/genericirq | |
10 | * | |
1da177e4 LT |
11 | */ |
12 | ||
13 | #include <linux/irq.h> | |
1da177e4 | 14 | #include <linux/random.h> |
3795de23 | 15 | #include <linux/sched.h> |
1da177e4 LT |
16 | #include <linux/interrupt.h> |
17 | #include <linux/kernel_stat.h> | |
3795de23 | 18 | |
ad8d75ff | 19 | #include <trace/events/irq.h> |
1da177e4 LT |
20 | |
21 | #include "internals.h" | |
22 | ||
6a6de9ef TG |
23 | /** |
24 | * handle_bad_irq - handle spurious and unhandled irqs | |
43a1dd50 | 25 | * @desc: description of the interrupt |
43a1dd50 HK |
26 | * |
27 | * Handles spurious and unhandled IRQ's. It also prints a debugmessage. | |
6a6de9ef | 28 | */ |
bd0b9ac4 | 29 | void handle_bad_irq(struct irq_desc *desc) |
6a6de9ef | 30 | { |
bd0b9ac4 TG |
31 | unsigned int irq = irq_desc_get_irq(desc); |
32 | ||
43f77759 | 33 | print_irq_desc(irq, desc); |
b51bf95c | 34 | kstat_incr_irqs_this_cpu(desc); |
6a6de9ef TG |
35 | ack_bad_irq(irq); |
36 | } | |
9d67dc5d | 37 | EXPORT_SYMBOL_GPL(handle_bad_irq); |
6a6de9ef | 38 | |
1da177e4 LT |
39 | /* |
40 | * Special, empty irq handler: | |
41 | */ | |
7d12e780 | 42 | irqreturn_t no_action(int cpl, void *dev_id) |
1da177e4 LT |
43 | { |
44 | return IRQ_NONE; | |
45 | } | |
d6ee6d23 | 46 | EXPORT_SYMBOL_GPL(no_action); |
1da177e4 | 47 | |
f48fe81e TG |
48 | static void warn_no_thread(unsigned int irq, struct irqaction *action) |
49 | { | |
50 | if (test_and_set_bit(IRQTF_WARNED, &action->thread_flags)) | |
51 | return; | |
52 | ||
53 | printk(KERN_WARNING "IRQ %d device %s returned IRQ_WAKE_THREAD " | |
54 | "but no thread function available.", irq, action->name); | |
55 | } | |
56 | ||
a92444c6 | 57 | void __irq_wake_thread(struct irq_desc *desc, struct irqaction *action) |
b5faba21 TG |
58 | { |
59 | /* | |
69592db2 AG |
60 | * In case the thread crashed and was killed we just pretend that |
61 | * we handled the interrupt. The hardirq handler has disabled the | |
62 | * device interrupt, so no irq storm is lurking. | |
63 | */ | |
64 | if (action->thread->flags & PF_EXITING) | |
65 | return; | |
66 | ||
67 | /* | |
68 | * Wake up the handler thread for this action. If the | |
b5faba21 TG |
69 | * RUNTHREAD bit is already set, nothing to do. |
70 | */ | |
69592db2 | 71 | if (test_and_set_bit(IRQTF_RUNTHREAD, &action->thread_flags)) |
b5faba21 TG |
72 | return; |
73 | ||
74 | /* | |
75 | * It's safe to OR the mask lockless here. We have only two | |
76 | * places which write to threads_oneshot: This code and the | |
77 | * irq thread. | |
78 | * | |
79 | * This code is the hard irq context and can never run on two | |
80 | * cpus in parallel. If it ever does we have more serious | |
81 | * problems than this bitmask. | |
82 | * | |
83 | * The irq threads of this irq which clear their "running" bit | |
84 | * in threads_oneshot are serialized via desc->lock against | |
85 | * each other and they are serialized against this code by | |
86 | * IRQS_INPROGRESS. | |
87 | * | |
88 | * Hard irq handler: | |
89 | * | |
90 | * spin_lock(desc->lock); | |
91 | * desc->state |= IRQS_INPROGRESS; | |
92 | * spin_unlock(desc->lock); | |
93 | * set_bit(IRQTF_RUNTHREAD, &action->thread_flags); | |
94 | * desc->threads_oneshot |= mask; | |
95 | * spin_lock(desc->lock); | |
96 | * desc->state &= ~IRQS_INPROGRESS; | |
97 | * spin_unlock(desc->lock); | |
98 | * | |
99 | * irq thread: | |
100 | * | |
101 | * again: | |
102 | * spin_lock(desc->lock); | |
103 | * if (desc->state & IRQS_INPROGRESS) { | |
104 | * spin_unlock(desc->lock); | |
105 | * while(desc->state & IRQS_INPROGRESS) | |
106 | * cpu_relax(); | |
107 | * goto again; | |
108 | * } | |
109 | * if (!test_bit(IRQTF_RUNTHREAD, &action->thread_flags)) | |
110 | * desc->threads_oneshot &= ~mask; | |
111 | * spin_unlock(desc->lock); | |
112 | * | |
113 | * So either the thread waits for us to clear IRQS_INPROGRESS | |
114 | * or we are waiting in the flow handler for desc->lock to be | |
115 | * released before we reach this point. The thread also checks | |
116 | * IRQTF_RUNTHREAD under desc->lock. If set it leaves | |
117 | * threads_oneshot untouched and runs the thread another time. | |
118 | */ | |
119 | desc->threads_oneshot |= action->thread_mask; | |
7140ea19 IY |
120 | |
121 | /* | |
122 | * We increment the threads_active counter in case we wake up | |
123 | * the irq thread. The irq thread decrements the counter when | |
124 | * it returns from the handler or in the exit path and wakes | |
125 | * up waiters which are stuck in synchronize_irq() when the | |
126 | * active count becomes zero. synchronize_irq() is serialized | |
127 | * against this code (hard irq handler) via IRQS_INPROGRESS | |
128 | * like the finalize_oneshot() code. See comment above. | |
129 | */ | |
130 | atomic_inc(&desc->threads_active); | |
131 | ||
b5faba21 TG |
132 | wake_up_process(action->thread); |
133 | } | |
134 | ||
71f64340 | 135 | irqreturn_t handle_irq_event_percpu(struct irq_desc *desc) |
1da177e4 | 136 | { |
70433c01 | 137 | irqreturn_t retval = IRQ_NONE; |
775f4b29 | 138 | unsigned int flags = 0, irq = desc->irq_data.irq; |
f944b5a7 | 139 | struct irqaction *action; |
1da177e4 | 140 | |
f944b5a7 | 141 | for_each_action_of_desc(desc, action) { |
70433c01 TG |
142 | irqreturn_t res; |
143 | ||
af39241b | 144 | trace_irq_handler_entry(irq, action); |
70433c01 TG |
145 | res = action->handler(irq, action->dev_id); |
146 | trace_irq_handler_exit(irq, action, res); | |
3aa551c9 | 147 | |
1204e956 TG |
148 | if (WARN_ONCE(!irqs_disabled(),"irq %u handler %pF enabled interrupts\n", |
149 | irq, action->handler)) | |
b738a50a TG |
150 | local_irq_disable(); |
151 | ||
70433c01 | 152 | switch (res) { |
3aa551c9 | 153 | case IRQ_WAKE_THREAD: |
f48fe81e TG |
154 | /* |
155 | * Catch drivers which return WAKE_THREAD but | |
156 | * did not set up a thread function | |
157 | */ | |
158 | if (unlikely(!action->thread_fn)) { | |
159 | warn_no_thread(irq, action); | |
160 | break; | |
161 | } | |
162 | ||
a92444c6 | 163 | __irq_wake_thread(desc, action); |
3aa551c9 | 164 | |
3aa551c9 TG |
165 | /* Fall through to add to randomness */ |
166 | case IRQ_HANDLED: | |
775f4b29 | 167 | flags |= action->flags; |
3aa551c9 TG |
168 | break; |
169 | ||
170 | default: | |
171 | break; | |
172 | } | |
173 | ||
70433c01 | 174 | retval |= res; |
570540d5 | 175 | } |
1da177e4 | 176 | |
775f4b29 | 177 | add_interrupt_randomness(irq, flags); |
1da177e4 | 178 | |
4912609f | 179 | if (!noirqdebug) |
0dcdbc97 | 180 | note_interrupt(desc, retval); |
1277a532 | 181 | return retval; |
4912609f TG |
182 | } |
183 | ||
184 | irqreturn_t handle_irq_event(struct irq_desc *desc) | |
185 | { | |
4912609f TG |
186 | irqreturn_t ret; |
187 | ||
2a0d6fb3 | 188 | desc->istate &= ~IRQS_PENDING; |
32f4125e | 189 | irqd_set(&desc->irq_data, IRQD_IRQ_INPROGRESS); |
4912609f TG |
190 | raw_spin_unlock(&desc->lock); |
191 | ||
71f64340 | 192 | ret = handle_irq_event_percpu(desc); |
4912609f TG |
193 | |
194 | raw_spin_lock(&desc->lock); | |
32f4125e | 195 | irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS); |
4912609f TG |
196 | return ret; |
197 | } |