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Thomas Gleixner52a65ff2018-03-14 22:15:19 +01001// SPDX-License-Identifier: GPL-2.0
Linus Torvalds1da177e2005-04-16 15:20:36 -07002/*
Ingo Molnara34db9b2006-06-29 02:24:50 -07003 * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
4 * Copyright (C) 2005-2006, Thomas Gleixner, Russell King
Linus Torvalds1da177e2005-04-16 15:20:36 -07005 *
Thomas Gleixner99bfce52018-03-14 22:15:16 +01006 * This file contains the core interrupt handling code. Detailed
7 * information is available in Documentation/core-api/genericirq.rst
Ingo Molnara34db9b2006-06-29 02:24:50 -07008 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07009 */
10
11#include <linux/irq.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <linux/random.h>
Thomas Gleixner3795de22010-09-22 17:09:43 +020013#include <linux/sched.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070014#include <linux/interrupt.h>
15#include <linux/kernel_stat.h>
Thomas Gleixner3795de22010-09-22 17:09:43 +020016
Steven Rostedtad8d75f2009-04-14 19:39:12 -040017#include <trace/events/irq.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070018
19#include "internals.h"
20
Palmer Dabbeltcaacdbf2018-03-07 15:57:27 -080021#ifdef CONFIG_GENERIC_IRQ_MULTI_HANDLER
22void (*handle_arch_irq)(struct pt_regs *) __ro_after_init;
23#endif
24
Thomas Gleixner6a6de9e2006-06-29 02:24:51 -070025/**
26 * handle_bad_irq - handle spurious and unhandled irqs
Henrik Kretzschmar43a1dd52006-08-31 21:27:44 -070027 * @desc: description of the interrupt
Henrik Kretzschmar43a1dd52006-08-31 21:27:44 -070028 *
29 * Handles spurious and unhandled IRQ's. It also prints a debugmessage.
Thomas Gleixner6a6de9e2006-06-29 02:24:51 -070030 */
Thomas Gleixnerbd0b9ac2015-09-14 10:42:37 +020031void handle_bad_irq(struct irq_desc *desc)
Thomas Gleixner6a6de9e2006-06-29 02:24:51 -070032{
Thomas Gleixnerbd0b9ac2015-09-14 10:42:37 +020033 unsigned int irq = irq_desc_get_irq(desc);
34
Ingo Molnar43f77752006-06-29 02:24:58 -070035 print_irq_desc(irq, desc);
Jiang Liub51bf952015-06-04 12:13:25 +080036 kstat_incr_irqs_this_cpu(desc);
Thomas Gleixner6a6de9e2006-06-29 02:24:51 -070037 ack_bad_irq(irq);
38}
Arnd Bergmann9d67dc52015-10-06 22:24:50 +020039EXPORT_SYMBOL_GPL(handle_bad_irq);
Thomas Gleixner6a6de9e2006-06-29 02:24:51 -070040
Thomas Gleixnerf8b54732006-07-01 22:30:08 +010041/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070042 * Special, empty irq handler:
43 */
David Howells7d12e782006-10-05 14:55:46 +010044irqreturn_t no_action(int cpl, void *dev_id)
Linus Torvalds1da177e2005-04-16 15:20:36 -070045{
46 return IRQ_NONE;
47}
Alexander Shiyand6ee6d22014-03-22 12:20:31 +040048EXPORT_SYMBOL_GPL(no_action);
Linus Torvalds1da177e2005-04-16 15:20:36 -070049
Thomas Gleixnerf48fe812009-03-24 11:46:22 +010050static 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
Thomas Gleixnera92444c2014-02-15 00:55:19 +000059void __irq_wake_thread(struct irq_desc *desc, struct irqaction *action)
Thomas Gleixnerb5faba22011-02-23 23:52:13 +000060{
61 /*
Alexander Gordeev69592db2012-03-21 17:22:13 +010062 * 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
Thomas Gleixnerb5faba22011-02-23 23:52:13 +000071 * RUNTHREAD bit is already set, nothing to do.
72 */
Alexander Gordeev69592db2012-03-21 17:22:13 +010073 if (test_and_set_bit(IRQTF_RUNTHREAD, &action->thread_flags))
Thomas Gleixnerb5faba22011-02-23 23:52:13 +000074 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;
Ido Yariv7140ea12011-12-02 18:24:12 +0200122
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
Thomas Gleixnerb5faba22011-02-23 23:52:13 +0000134 wake_up_process(action->thread);
135}
136
Keith Buschedd14cf2016-06-17 16:00:20 -0600137irqreturn_t __handle_irq_event_percpu(struct irq_desc *desc, unsigned int *flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138{
Thomas Gleixner70433c02011-02-22 12:50:12 +0100139 irqreturn_t retval = IRQ_NONE;
Keith Buschedd14cf2016-06-17 16:00:20 -0600140 unsigned int irq = desc->irq_data.irq;
Daniel Lezcanof944b5a2016-01-14 10:54:13 +0100141 struct irqaction *action;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142
Daniel Lezcanob2d3d612017-06-23 16:11:07 +0200143 record_irq_time(desc);
144
Daniel Lezcanof944b5a2016-01-14 10:54:13 +0100145 for_each_action_of_desc(desc, action) {
Thomas Gleixner70433c02011-02-22 12:50:12 +0100146 irqreturn_t res;
147
Peter Zijlstrade8f5e42020-03-21 12:26:01 +0100148 /*
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)))
Linus Torvaldsd5f744f2020-03-30 19:14:28 -0700153 lockdep_hardirq_threaded();
Peter Zijlstrade8f5e42020-03-21 12:26:01 +0100154
Jason Baronaf392412009-02-26 10:11:05 -0500155 trace_irq_handler_entry(irq, action);
Thomas Gleixner70433c02011-02-22 12:50:12 +0100156 res = action->handler(irq, action->dev_id);
157 trace_irq_handler_exit(irq, action, res);
Thomas Gleixner3aa551c2009-03-23 18:28:15 +0100158
Sakari Ailusd75f7732019-03-25 21:32:28 +0200159 if (WARN_ONCE(!irqs_disabled(),"irq %u handler %pS enabled interrupts\n",
Thomas Gleixner1204e952011-02-25 17:17:18 +0100160 irq, action->handler))
Thomas Gleixnerb738a502011-02-02 23:58:19 +0100161 local_irq_disable();
162
Thomas Gleixner70433c02011-02-22 12:50:12 +0100163 switch (res) {
Thomas Gleixner3aa551c2009-03-23 18:28:15 +0100164 case IRQ_WAKE_THREAD:
165 /*
Thomas Gleixnerf48fe812009-03-24 11:46:22 +0100166 * 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
Thomas Gleixnera92444c2014-02-15 00:55:19 +0000174 __irq_wake_thread(desc, action);
Thomas Gleixner3aa551c2009-03-23 18:28:15 +0100175
Gustavo A. R. Silvadf561f662020-08-23 17:36:59 -0500176 fallthrough; /* to add to randomness */
Thomas Gleixner3aa551c2009-03-23 18:28:15 +0100177 case IRQ_HANDLED:
Keith Buschedd14cf2016-06-17 16:00:20 -0600178 *flags |= action->flags;
Thomas Gleixner3aa551c2009-03-23 18:28:15 +0100179 break;
180
181 default:
182 break;
183 }
184
Thomas Gleixner70433c02011-02-22 12:50:12 +0100185 retval |= res;
Thomas Gleixner570540d52016-01-13 14:07:25 +0100186 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187
Keith Buschedd14cf2016-06-17 16:00:20 -0600188 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);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199
Thomas Gleixner49126092011-02-07 01:08:49 +0100200 if (!noirqdebug)
Jiang Liu0dcdbc92015-06-04 12:13:28 +0800201 note_interrupt(desc, retval);
Thomas Gleixner1277a532011-02-07 01:40:27 +0100202 return retval;
Thomas Gleixner49126092011-02-07 01:08:49 +0100203}
204
205irqreturn_t handle_irq_event(struct irq_desc *desc)
206{
Thomas Gleixner49126092011-02-07 01:08:49 +0100207 irqreturn_t ret;
208
Thomas Gleixner2a0d6fb2011-02-08 12:17:57 +0100209 desc->istate &= ~IRQS_PENDING;
Thomas Gleixner32f41252011-03-28 14:10:52 +0200210 irqd_set(&desc->irq_data, IRQD_IRQ_INPROGRESS);
Thomas Gleixner49126092011-02-07 01:08:49 +0100211 raw_spin_unlock(&desc->lock);
212
Huang Shijie71f64342015-09-02 10:24:55 +0800213 ret = handle_irq_event_percpu(desc);
Thomas Gleixner49126092011-02-07 01:08:49 +0100214
215 raw_spin_lock(&desc->lock);
Thomas Gleixner32f41252011-03-28 14:10:52 +0200216 irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
Thomas Gleixner49126092011-02-07 01:08:49 +0100217 return ret;
218}
Palmer Dabbeltcaacdbf2018-03-07 15:57:27 -0800219
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