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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 * @desc: description of the interrupt
26 *
27 * Handles spurious and unhandled IRQ's. It also prints a debugmessage.
28 */
29void handle_bad_irq(struct irq_desc *desc)
30{
31 unsigned int irq = irq_desc_get_irq(desc);
32
33 print_irq_desc(irq, desc);
34 kstat_incr_irqs_this_cpu(desc);
35 ack_bad_irq(irq);
36}
37EXPORT_SYMBOL_GPL(handle_bad_irq);
38
39/*
40 * Special, empty irq handler:
41 */
42irqreturn_t no_action(int cpl, void *dev_id)
43{
44 return IRQ_NONE;
45}
46EXPORT_SYMBOL_GPL(no_action);
47
48static 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
57void __irq_wake_thread(struct irq_desc *desc, struct irqaction *action)
58{
59 /*
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
69 * RUNTHREAD bit is already set, nothing to do.
70 */
71 if (test_and_set_bit(IRQTF_RUNTHREAD, &action->thread_flags))
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;
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
132 wake_up_process(action->thread);
133}
134
135irqreturn_t handle_irq_event_percpu(struct irq_desc *desc)
136{
137 irqreturn_t retval = IRQ_NONE;
138 unsigned int flags = 0, irq = desc->irq_data.irq;
139 struct irqaction *action;
140
141 for_each_action_of_desc(desc, action) {
142 irqreturn_t res;
143
144 trace_irq_handler_entry(irq, action);
145 res = action->handler(irq, action->dev_id);
146 trace_irq_handler_exit(irq, action, res);
147
148 if (WARN_ONCE(!irqs_disabled(),"irq %u handler %pF enabled interrupts\n",
149 irq, action->handler))
150 local_irq_disable();
151
152 switch (res) {
153 case IRQ_WAKE_THREAD:
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
163 __irq_wake_thread(desc, action);
164
165 /* Fall through to add to randomness */
166 case IRQ_HANDLED:
167 flags |= action->flags;
168 break;
169
170 default:
171 break;
172 }
173
174 retval |= res;
175 }
176
177 add_interrupt_randomness(irq, flags);
178
179 if (!noirqdebug)
180 note_interrupt(desc, retval);
181 return retval;
182}
183
184irqreturn_t handle_irq_event(struct irq_desc *desc)
185{
186 irqreturn_t ret;
187
188 desc->istate &= ~IRQS_PENDING;
189 irqd_set(&desc->irq_data, IRQD_IRQ_INPROGRESS);
190 raw_spin_unlock(&desc->lock);
191
192 ret = handle_irq_event_percpu(desc);
193
194 raw_spin_lock(&desc->lock);
195 irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
196 return ret;
197}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
4 * Copyright (C) 2005-2006, Thomas Gleixner, Russell King
5 *
6 * This file contains the core interrupt handling code. Detailed
7 * information is available in Documentation/core-api/genericirq.rst
8 *
9 */
10
11#include <linux/irq.h>
12#include <linux/random.h>
13#include <linux/sched.h>
14#include <linux/interrupt.h>
15#include <linux/kernel_stat.h>
16
17#include <trace/events/irq.h>
18
19#include "internals.h"
20
21#ifdef CONFIG_GENERIC_IRQ_MULTI_HANDLER
22void (*handle_arch_irq)(struct pt_regs *) __ro_after_init;
23#endif
24
25/**
26 * handle_bad_irq - handle spurious and unhandled irqs
27 * @desc: description of the interrupt
28 *
29 * Handles spurious and unhandled IRQ's. It also prints a debugmessage.
30 */
31void handle_bad_irq(struct irq_desc *desc)
32{
33 unsigned int irq = irq_desc_get_irq(desc);
34
35 print_irq_desc(irq, desc);
36 kstat_incr_irqs_this_cpu(desc);
37 ack_bad_irq(irq);
38}
39EXPORT_SYMBOL_GPL(handle_bad_irq);
40
41/*
42 * Special, empty irq handler:
43 */
44irqreturn_t no_action(int cpl, void *dev_id)
45{
46 return IRQ_NONE;
47}
48EXPORT_SYMBOL_GPL(no_action);
49
50static void warn_no_thread(unsigned int irq, struct irqaction *action)
51{
52 if (test_and_set_bit(IRQTF_WARNED, &action->thread_flags))
53 return;
54
55 printk(KERN_WARNING "IRQ %d device %s returned IRQ_WAKE_THREAD "
56 "but no thread function available.", irq, action->name);
57}
58
59void __irq_wake_thread(struct irq_desc *desc, struct irqaction *action)
60{
61 /*
62 * In case the thread crashed and was killed we just pretend that
63 * we handled the interrupt. The hardirq handler has disabled the
64 * device interrupt, so no irq storm is lurking.
65 */
66 if (action->thread->flags & PF_EXITING)
67 return;
68
69 /*
70 * Wake up the handler thread for this action. If the
71 * RUNTHREAD bit is already set, nothing to do.
72 */
73 if (test_and_set_bit(IRQTF_RUNTHREAD, &action->thread_flags))
74 return;
75
76 /*
77 * It's safe to OR the mask lockless here. We have only two
78 * places which write to threads_oneshot: This code and the
79 * irq thread.
80 *
81 * This code is the hard irq context and can never run on two
82 * cpus in parallel. If it ever does we have more serious
83 * problems than this bitmask.
84 *
85 * The irq threads of this irq which clear their "running" bit
86 * in threads_oneshot are serialized via desc->lock against
87 * each other and they are serialized against this code by
88 * IRQS_INPROGRESS.
89 *
90 * Hard irq handler:
91 *
92 * spin_lock(desc->lock);
93 * desc->state |= IRQS_INPROGRESS;
94 * spin_unlock(desc->lock);
95 * set_bit(IRQTF_RUNTHREAD, &action->thread_flags);
96 * desc->threads_oneshot |= mask;
97 * spin_lock(desc->lock);
98 * desc->state &= ~IRQS_INPROGRESS;
99 * spin_unlock(desc->lock);
100 *
101 * irq thread:
102 *
103 * again:
104 * spin_lock(desc->lock);
105 * if (desc->state & IRQS_INPROGRESS) {
106 * spin_unlock(desc->lock);
107 * while(desc->state & IRQS_INPROGRESS)
108 * cpu_relax();
109 * goto again;
110 * }
111 * if (!test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
112 * desc->threads_oneshot &= ~mask;
113 * spin_unlock(desc->lock);
114 *
115 * So either the thread waits for us to clear IRQS_INPROGRESS
116 * or we are waiting in the flow handler for desc->lock to be
117 * released before we reach this point. The thread also checks
118 * IRQTF_RUNTHREAD under desc->lock. If set it leaves
119 * threads_oneshot untouched and runs the thread another time.
120 */
121 desc->threads_oneshot |= action->thread_mask;
122
123 /*
124 * We increment the threads_active counter in case we wake up
125 * the irq thread. The irq thread decrements the counter when
126 * it returns from the handler or in the exit path and wakes
127 * up waiters which are stuck in synchronize_irq() when the
128 * active count becomes zero. synchronize_irq() is serialized
129 * against this code (hard irq handler) via IRQS_INPROGRESS
130 * like the finalize_oneshot() code. See comment above.
131 */
132 atomic_inc(&desc->threads_active);
133
134 wake_up_process(action->thread);
135}
136
137irqreturn_t __handle_irq_event_percpu(struct irq_desc *desc, unsigned int *flags)
138{
139 irqreturn_t retval = IRQ_NONE;
140 unsigned int irq = desc->irq_data.irq;
141 struct irqaction *action;
142
143 record_irq_time(desc);
144
145 for_each_action_of_desc(desc, action) {
146 irqreturn_t res;
147
148 /*
149 * If this IRQ would be threaded under force_irqthreads, mark it so.
150 */
151 if (irq_settings_can_thread(desc) &&
152 !(action->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT)))
153 lockdep_hardirq_threaded();
154
155 trace_irq_handler_entry(irq, action);
156 res = action->handler(irq, action->dev_id);
157 trace_irq_handler_exit(irq, action, res);
158
159 if (WARN_ONCE(!irqs_disabled(),"irq %u handler %pS enabled interrupts\n",
160 irq, action->handler))
161 local_irq_disable();
162
163 switch (res) {
164 case IRQ_WAKE_THREAD:
165 /*
166 * Catch drivers which return WAKE_THREAD but
167 * did not set up a thread function
168 */
169 if (unlikely(!action->thread_fn)) {
170 warn_no_thread(irq, action);
171 break;
172 }
173
174 __irq_wake_thread(desc, action);
175
176 fallthrough; /* to add to randomness */
177 case IRQ_HANDLED:
178 *flags |= action->flags;
179 break;
180
181 default:
182 break;
183 }
184
185 retval |= res;
186 }
187
188 return retval;
189}
190
191irqreturn_t handle_irq_event_percpu(struct irq_desc *desc)
192{
193 irqreturn_t retval;
194 unsigned int flags = 0;
195
196 retval = __handle_irq_event_percpu(desc, &flags);
197
198 add_interrupt_randomness(desc->irq_data.irq, flags);
199
200 if (!noirqdebug)
201 note_interrupt(desc, retval);
202 return retval;
203}
204
205irqreturn_t handle_irq_event(struct irq_desc *desc)
206{
207 irqreturn_t ret;
208
209 desc->istate &= ~IRQS_PENDING;
210 irqd_set(&desc->irq_data, IRQD_IRQ_INPROGRESS);
211 raw_spin_unlock(&desc->lock);
212
213 ret = handle_irq_event_percpu(desc);
214
215 raw_spin_lock(&desc->lock);
216 irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
217 return ret;
218}
219
220#ifdef CONFIG_GENERIC_IRQ_MULTI_HANDLER
221int __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
222{
223 if (handle_arch_irq)
224 return -EBUSY;
225
226 handle_arch_irq = handle_irq;
227 return 0;
228}
229#endif