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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 HK |
25 | * @irq: the interrupt number |
26 | * @desc: description of the interrupt | |
43a1dd50 HK |
27 | * |
28 | * Handles spurious and unhandled IRQ's. It also prints a debugmessage. | |
6a6de9ef | 29 | */ |
d6c88a50 | 30 | void handle_bad_irq(unsigned int irq, struct irq_desc *desc) |
6a6de9ef | 31 | { |
43f77759 | 32 | print_irq_desc(irq, desc); |
d6c88a50 | 33 | kstat_incr_irqs_this_cpu(irq, desc); |
6a6de9ef TG |
34 | ack_bad_irq(irq); |
35 | } | |
36 | ||
1da177e4 LT |
37 | /* |
38 | * Special, empty irq handler: | |
39 | */ | |
7d12e780 | 40 | irqreturn_t no_action(int cpl, void *dev_id) |
1da177e4 LT |
41 | { |
42 | return IRQ_NONE; | |
43 | } | |
44 | ||
f48fe81e TG |
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 | ||
8d28bc75 IM |
54 | /** |
55 | * handle_IRQ_event - irq action chain handler | |
56 | * @irq: the interrupt number | |
8d28bc75 IM |
57 | * @action: the interrupt action chain for this irq |
58 | * | |
59 | * Handles the action chain of an irq event | |
1da177e4 | 60 | */ |
7d12e780 | 61 | irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action) |
1da177e4 | 62 | { |
908dcecd JB |
63 | irqreturn_t ret, retval = IRQ_NONE; |
64 | unsigned int status = 0; | |
1da177e4 | 65 | |
1da177e4 | 66 | do { |
af39241b | 67 | trace_irq_handler_entry(irq, action); |
7d12e780 | 68 | ret = action->handler(irq, action->dev_id); |
af39241b | 69 | trace_irq_handler_exit(irq, action, ret); |
3aa551c9 TG |
70 | |
71 | switch (ret) { | |
72 | case IRQ_WAKE_THREAD: | |
f48fe81e TG |
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 | ||
3aa551c9 TG |
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 | ||
3aa551c9 TG |
102 | /* Fall through to add to randomness */ |
103 | case IRQ_HANDLED: | |
1da177e4 | 104 | status |= action->flags; |
3aa551c9 TG |
105 | break; |
106 | ||
107 | default: | |
108 | break; | |
109 | } | |
110 | ||
1da177e4 LT |
111 | retval |= ret; |
112 | action = action->next; | |
113 | } while (action); | |
114 | ||
3cca53b0 | 115 | if (status & IRQF_SAMPLE_RANDOM) |
1da177e4 LT |
116 | add_interrupt_randomness(irq); |
117 | local_irq_disable(); | |
118 | ||
119 | return retval; | |
120 | } | |
121 | ||
af8c65b5 | 122 | #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ |
0e57aa11 TG |
123 | |
124 | #ifdef CONFIG_ENABLE_WARN_DEPRECATED | |
125 | # warning __do_IRQ is deprecated. Please convert to proper flow handlers | |
126 | #endif | |
127 | ||
8d28bc75 IM |
128 | /** |
129 | * __do_IRQ - original all in one highlevel IRQ handler | |
130 | * @irq: the interrupt number | |
8d28bc75 IM |
131 | * |
132 | * __do_IRQ handles all normal device IRQ's (the special | |
1da177e4 LT |
133 | * SMP cross-CPU interrupts have their own specific |
134 | * handlers). | |
8d28bc75 IM |
135 | * |
136 | * This is the original x86 implementation which is used for every | |
137 | * interrupt type. | |
1da177e4 | 138 | */ |
7ad5b3a5 | 139 | unsigned int __do_IRQ(unsigned int irq) |
1da177e4 | 140 | { |
08678b08 | 141 | struct irq_desc *desc = irq_to_desc(irq); |
06fcb0c6 | 142 | struct irqaction *action; |
1da177e4 LT |
143 | unsigned int status; |
144 | ||
d6c88a50 TG |
145 | kstat_incr_irqs_this_cpu(irq, desc); |
146 | ||
f26fdd59 | 147 | if (CHECK_IRQ_PER_CPU(desc->status)) { |
1da177e4 LT |
148 | irqreturn_t action_ret; |
149 | ||
150 | /* | |
151 | * No locking required for CPU-local interrupts: | |
152 | */ | |
6b8ff312 TG |
153 | if (desc->irq_data.chip->ack) |
154 | desc->irq_data.chip->ack(irq); | |
c642b839 RA |
155 | if (likely(!(desc->status & IRQ_DISABLED))) { |
156 | action_ret = handle_IRQ_event(irq, desc->action); | |
157 | if (!noirqdebug) | |
158 | note_interrupt(irq, desc, action_ret); | |
159 | } | |
6b8ff312 | 160 | desc->irq_data.chip->end(irq); |
1da177e4 LT |
161 | return 1; |
162 | } | |
163 | ||
239007b8 | 164 | raw_spin_lock(&desc->lock); |
6b8ff312 TG |
165 | if (desc->irq_data.chip->ack) |
166 | desc->irq_data.chip->ack(irq); | |
1da177e4 LT |
167 | /* |
168 | * REPLAY is when Linux resends an IRQ that was dropped earlier | |
169 | * WAITING is used by probe to mark irqs that are being tested | |
170 | */ | |
171 | status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING); | |
172 | status |= IRQ_PENDING; /* we _want_ to handle it */ | |
173 | ||
174 | /* | |
175 | * If the IRQ is disabled for whatever reason, we cannot | |
176 | * use the action we have. | |
177 | */ | |
178 | action = NULL; | |
179 | if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) { | |
180 | action = desc->action; | |
181 | status &= ~IRQ_PENDING; /* we commit to handling */ | |
182 | status |= IRQ_INPROGRESS; /* we are handling it */ | |
183 | } | |
184 | desc->status = status; | |
185 | ||
186 | /* | |
187 | * If there is no IRQ handler or it was disabled, exit early. | |
188 | * Since we set PENDING, if another processor is handling | |
189 | * a different instance of this same irq, the other processor | |
190 | * will take care of it. | |
191 | */ | |
192 | if (unlikely(!action)) | |
193 | goto out; | |
194 | ||
195 | /* | |
196 | * Edge triggered interrupts need to remember | |
197 | * pending events. | |
198 | * This applies to any hw interrupts that allow a second | |
199 | * instance of the same irq to arrive while we are in do_IRQ | |
200 | * or in the handler. But the code here only handles the _second_ | |
201 | * instance of the irq, not the third or fourth. So it is mostly | |
202 | * useful for irq hardware that does not mask cleanly in an | |
203 | * SMP environment. | |
204 | */ | |
205 | for (;;) { | |
206 | irqreturn_t action_ret; | |
207 | ||
239007b8 | 208 | raw_spin_unlock(&desc->lock); |
1da177e4 | 209 | |
7d12e780 | 210 | action_ret = handle_IRQ_event(irq, action); |
1da177e4 | 211 | if (!noirqdebug) |
7d12e780 | 212 | note_interrupt(irq, desc, action_ret); |
b42172fc | 213 | |
239007b8 | 214 | raw_spin_lock(&desc->lock); |
1da177e4 LT |
215 | if (likely(!(desc->status & IRQ_PENDING))) |
216 | break; | |
217 | desc->status &= ~IRQ_PENDING; | |
218 | } | |
219 | desc->status &= ~IRQ_INPROGRESS; | |
220 | ||
221 | out: | |
222 | /* | |
223 | * The ->end() handler has to deal with interrupts which got | |
224 | * disabled while the handler was running. | |
225 | */ | |
6b8ff312 | 226 | desc->irq_data.chip->end(irq); |
239007b8 | 227 | raw_spin_unlock(&desc->lock); |
1da177e4 LT |
228 | |
229 | return 1; | |
230 | } | |
af8c65b5 | 231 | #endif |