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