1 // SPDX-License-Identifier: GPL-2.0 <<
2 /* 1 /*
>> 2 * linux/kernel/irq/handle.c
>> 3 *
3 * Copyright (C) 1992, 1998-2006 Linus Torvald 4 * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
4 * Copyright (C) 2005-2006, Thomas Gleixner, R 5 * Copyright (C) 2005-2006, Thomas Gleixner, Russell King
5 * 6 *
6 * This file contains the core interrupt handl !! 7 * This file contains the core interrupt handling code.
7 * information is available in Documentation/c !! 8 *
>> 9 * Detailed information is available in Documentation/core-api/genericirq.rst
8 * 10 *
9 */ 11 */
10 12
11 #include <linux/irq.h> 13 #include <linux/irq.h>
12 #include <linux/random.h> 14 #include <linux/random.h>
13 #include <linux/sched.h> 15 #include <linux/sched.h>
14 #include <linux/interrupt.h> 16 #include <linux/interrupt.h>
15 #include <linux/kernel_stat.h> 17 #include <linux/kernel_stat.h>
16 18
17 #include <asm/irq_regs.h> <<
18 <<
19 #include <trace/events/irq.h> 19 #include <trace/events/irq.h>
20 20
21 #include "internals.h" 21 #include "internals.h"
22 22
23 #ifdef CONFIG_GENERIC_IRQ_MULTI_HANDLER <<
24 void (*handle_arch_irq)(struct pt_regs *) __ro <<
25 #endif <<
26 <<
27 /** 23 /**
28 * handle_bad_irq - handle spurious and unhand 24 * handle_bad_irq - handle spurious and unhandled irqs
29 * @desc: description of the interrupt 25 * @desc: description of the interrupt
30 * 26 *
31 * Handles spurious and unhandled IRQ's. It al 27 * Handles spurious and unhandled IRQ's. It also prints a debugmessage.
32 */ 28 */
33 void handle_bad_irq(struct irq_desc *desc) 29 void handle_bad_irq(struct irq_desc *desc)
34 { 30 {
35 unsigned int irq = irq_desc_get_irq(de 31 unsigned int irq = irq_desc_get_irq(desc);
36 32
37 print_irq_desc(irq, desc); 33 print_irq_desc(irq, desc);
38 kstat_incr_irqs_this_cpu(desc); 34 kstat_incr_irqs_this_cpu(desc);
39 ack_bad_irq(irq); 35 ack_bad_irq(irq);
40 } 36 }
41 EXPORT_SYMBOL_GPL(handle_bad_irq); 37 EXPORT_SYMBOL_GPL(handle_bad_irq);
42 38
43 /* 39 /*
44 * Special, empty irq handler: 40 * Special, empty irq handler:
45 */ 41 */
46 irqreturn_t no_action(int cpl, void *dev_id) 42 irqreturn_t no_action(int cpl, void *dev_id)
47 { 43 {
48 return IRQ_NONE; 44 return IRQ_NONE;
49 } 45 }
50 EXPORT_SYMBOL_GPL(no_action); 46 EXPORT_SYMBOL_GPL(no_action);
51 47
52 static void warn_no_thread(unsigned int irq, s 48 static void warn_no_thread(unsigned int irq, struct irqaction *action)
53 { 49 {
54 if (test_and_set_bit(IRQTF_WARNED, &ac 50 if (test_and_set_bit(IRQTF_WARNED, &action->thread_flags))
55 return; 51 return;
56 52
57 printk(KERN_WARNING "IRQ %d device %s 53 printk(KERN_WARNING "IRQ %d device %s returned IRQ_WAKE_THREAD "
58 "but no thread function availab 54 "but no thread function available.", irq, action->name);
59 } 55 }
60 56
61 void __irq_wake_thread(struct irq_desc *desc, 57 void __irq_wake_thread(struct irq_desc *desc, struct irqaction *action)
62 { 58 {
63 /* 59 /*
64 * In case the thread crashed and was 60 * In case the thread crashed and was killed we just pretend that
65 * we handled the interrupt. The hardi 61 * we handled the interrupt. The hardirq handler has disabled the
66 * device interrupt, so no irq storm i 62 * device interrupt, so no irq storm is lurking.
67 */ 63 */
68 if (action->thread->flags & PF_EXITING 64 if (action->thread->flags & PF_EXITING)
69 return; 65 return;
70 66
71 /* 67 /*
72 * Wake up the handler thread for this 68 * Wake up the handler thread for this action. If the
73 * RUNTHREAD bit is already set, nothi 69 * RUNTHREAD bit is already set, nothing to do.
74 */ 70 */
75 if (test_and_set_bit(IRQTF_RUNTHREAD, 71 if (test_and_set_bit(IRQTF_RUNTHREAD, &action->thread_flags))
76 return; 72 return;
77 73
78 /* 74 /*
79 * It's safe to OR the mask lockless h 75 * It's safe to OR the mask lockless here. We have only two
80 * places which write to threads_onesh 76 * places which write to threads_oneshot: This code and the
81 * irq thread. 77 * irq thread.
82 * 78 *
83 * This code is the hard irq context a 79 * This code is the hard irq context and can never run on two
84 * cpus in parallel. If it ever does w 80 * cpus in parallel. If it ever does we have more serious
85 * problems than this bitmask. 81 * problems than this bitmask.
86 * 82 *
87 * The irq threads of this irq which c 83 * The irq threads of this irq which clear their "running" bit
88 * in threads_oneshot are serialized v 84 * in threads_oneshot are serialized via desc->lock against
89 * each other and they are serialized 85 * each other and they are serialized against this code by
90 * IRQS_INPROGRESS. 86 * IRQS_INPROGRESS.
91 * 87 *
92 * Hard irq handler: 88 * Hard irq handler:
93 * 89 *
94 * spin_lock(desc->lock); 90 * spin_lock(desc->lock);
95 * desc->state |= IRQS_INPROGRESS 91 * desc->state |= IRQS_INPROGRESS;
96 * spin_unlock(desc->lock); 92 * spin_unlock(desc->lock);
97 * set_bit(IRQTF_RUNTHREAD, &acti 93 * set_bit(IRQTF_RUNTHREAD, &action->thread_flags);
98 * desc->threads_oneshot |= mask; 94 * desc->threads_oneshot |= mask;
99 * spin_lock(desc->lock); 95 * spin_lock(desc->lock);
100 * desc->state &= ~IRQS_INPROGRES 96 * desc->state &= ~IRQS_INPROGRESS;
101 * spin_unlock(desc->lock); 97 * spin_unlock(desc->lock);
102 * 98 *
103 * irq thread: 99 * irq thread:
104 * 100 *
105 * again: 101 * again:
106 * spin_lock(desc->lock); 102 * spin_lock(desc->lock);
107 * if (desc->state & IRQS_INPROGR 103 * if (desc->state & IRQS_INPROGRESS) {
108 * spin_unlock(desc->lock 104 * spin_unlock(desc->lock);
109 * while(desc->state & IR 105 * while(desc->state & IRQS_INPROGRESS)
110 * cpu_relax(); 106 * cpu_relax();
111 * goto again; 107 * goto again;
112 * } 108 * }
113 * if (!test_bit(IRQTF_RUNTHREAD, 109 * if (!test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
114 * desc->threads_oneshot 110 * desc->threads_oneshot &= ~mask;
115 * spin_unlock(desc->lock); 111 * spin_unlock(desc->lock);
116 * 112 *
117 * So either the thread waits for us t 113 * So either the thread waits for us to clear IRQS_INPROGRESS
118 * or we are waiting in the flow handl 114 * or we are waiting in the flow handler for desc->lock to be
119 * released before we reach this point 115 * released before we reach this point. The thread also checks
120 * IRQTF_RUNTHREAD under desc->lock. I 116 * IRQTF_RUNTHREAD under desc->lock. If set it leaves
121 * threads_oneshot untouched and runs 117 * threads_oneshot untouched and runs the thread another time.
122 */ 118 */
123 desc->threads_oneshot |= action->threa 119 desc->threads_oneshot |= action->thread_mask;
124 120
125 /* 121 /*
126 * We increment the threads_active cou 122 * We increment the threads_active counter in case we wake up
127 * the irq thread. The irq thread decr 123 * the irq thread. The irq thread decrements the counter when
128 * it returns from the handler or in t 124 * it returns from the handler or in the exit path and wakes
129 * up waiters which are stuck in synch 125 * up waiters which are stuck in synchronize_irq() when the
130 * active count becomes zero. synchron 126 * active count becomes zero. synchronize_irq() is serialized
131 * against this code (hard irq handler 127 * against this code (hard irq handler) via IRQS_INPROGRESS
132 * like the finalize_oneshot() code. S 128 * like the finalize_oneshot() code. See comment above.
133 */ 129 */
134 atomic_inc(&desc->threads_active); 130 atomic_inc(&desc->threads_active);
135 131
136 wake_up_process(action->thread); 132 wake_up_process(action->thread);
137 } 133 }
138 134
139 irqreturn_t __handle_irq_event_percpu(struct i !! 135 irqreturn_t __handle_irq_event_percpu(struct irq_desc *desc, unsigned int *flags)
140 { 136 {
141 irqreturn_t retval = IRQ_NONE; 137 irqreturn_t retval = IRQ_NONE;
142 unsigned int irq = desc->irq_data.irq; 138 unsigned int irq = desc->irq_data.irq;
143 struct irqaction *action; 139 struct irqaction *action;
144 140
145 record_irq_time(desc); 141 record_irq_time(desc);
146 142
147 for_each_action_of_desc(desc, action) 143 for_each_action_of_desc(desc, action) {
148 irqreturn_t res; 144 irqreturn_t res;
149 145
150 /* <<
151 * If this IRQ would be thread <<
152 */ <<
153 if (irq_settings_can_thread(de <<
154 !(action->flags & (IRQF_NO <<
155 lockdep_hardirq_thread <<
156 <<
157 trace_irq_handler_entry(irq, a 146 trace_irq_handler_entry(irq, action);
158 res = action->handler(irq, act 147 res = action->handler(irq, action->dev_id);
159 trace_irq_handler_exit(irq, ac 148 trace_irq_handler_exit(irq, action, res);
160 149
161 if (WARN_ONCE(!irqs_disabled() !! 150 if (WARN_ONCE(!irqs_disabled(),"irq %u handler %pF enabled interrupts\n",
162 irq, action->han 151 irq, action->handler))
163 local_irq_disable(); 152 local_irq_disable();
164 153
165 switch (res) { 154 switch (res) {
166 case IRQ_WAKE_THREAD: 155 case IRQ_WAKE_THREAD:
167 /* 156 /*
168 * Catch drivers which 157 * Catch drivers which return WAKE_THREAD but
169 * did not set up a th 158 * did not set up a thread function
170 */ 159 */
171 if (unlikely(!action-> 160 if (unlikely(!action->thread_fn)) {
172 warn_no_thread 161 warn_no_thread(irq, action);
173 break; 162 break;
174 } 163 }
175 164
176 __irq_wake_thread(desc 165 __irq_wake_thread(desc, action);
>> 166
>> 167 /* Fall through to add to randomness */
>> 168 case IRQ_HANDLED:
>> 169 *flags |= action->flags;
177 break; 170 break;
178 171
179 default: 172 default:
180 break; 173 break;
181 } 174 }
182 175
183 retval |= res; 176 retval |= res;
184 } 177 }
185 178
186 return retval; 179 return retval;
187 } 180 }
188 181
189 irqreturn_t handle_irq_event_percpu(struct irq 182 irqreturn_t handle_irq_event_percpu(struct irq_desc *desc)
190 { 183 {
191 irqreturn_t retval; 184 irqreturn_t retval;
>> 185 unsigned int flags = 0;
192 186
193 retval = __handle_irq_event_percpu(des !! 187 retval = __handle_irq_event_percpu(desc, &flags);
194 188
195 add_interrupt_randomness(desc->irq_dat 189 add_interrupt_randomness(desc->irq_data.irq);
196 190
197 if (!irq_settings_no_debug(desc)) !! 191 if (!noirqdebug)
198 note_interrupt(desc, retval); 192 note_interrupt(desc, retval);
199 return retval; 193 return retval;
200 } 194 }
201 195
202 irqreturn_t handle_irq_event(struct irq_desc * 196 irqreturn_t handle_irq_event(struct irq_desc *desc)
203 { 197 {
204 irqreturn_t ret; 198 irqreturn_t ret;
205 199
206 desc->istate &= ~IRQS_PENDING; 200 desc->istate &= ~IRQS_PENDING;
207 irqd_set(&desc->irq_data, IRQD_IRQ_INP 201 irqd_set(&desc->irq_data, IRQD_IRQ_INPROGRESS);
208 raw_spin_unlock(&desc->lock); 202 raw_spin_unlock(&desc->lock);
209 203
210 ret = handle_irq_event_percpu(desc); 204 ret = handle_irq_event_percpu(desc);
211 205
212 raw_spin_lock(&desc->lock); 206 raw_spin_lock(&desc->lock);
213 irqd_clear(&desc->irq_data, IRQD_IRQ_I 207 irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
214 return ret; 208 return ret;
215 } 209 }
216 <<
217 #ifdef CONFIG_GENERIC_IRQ_MULTI_HANDLER <<
218 int __init set_handle_irq(void (*handle_irq)(s <<
219 { <<
220 if (handle_arch_irq) <<
221 return -EBUSY; <<
222 <<
223 handle_arch_irq = handle_irq; <<
224 return 0; <<
225 } <<
226 <<
227 /** <<
228 * generic_handle_arch_irq - root irq handler <<
229 * entry accounting <<
230 * @regs: Register file coming from the <<
231 */ <<
232 asmlinkage void noinstr generic_handle_arch_ir <<
233 { <<
234 struct pt_regs *old_regs; <<
235 <<
236 irq_enter(); <<
237 old_regs = set_irq_regs(regs); <<
238 handle_arch_irq(regs); <<
239 set_irq_regs(old_regs); <<
240 irq_exit(); <<
241 } <<
242 #endif <<
243 210
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