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52a65ff5 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 | 2 | /* |
a34db9b2 IM |
3 | * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar |
4 | * Copyright (C) 2005-2006, Thomas Gleixner, Russell King | |
1da177e4 | 5 | * |
99bfce5d TG |
6 | * This file contains the core interrupt handling code. Detailed |
7 | * information is available in Documentation/core-api/genericirq.rst | |
a34db9b2 | 8 | * |
1da177e4 LT |
9 | */ |
10 | ||
11 | #include <linux/irq.h> | |
1da177e4 | 12 | #include <linux/random.h> |
3795de23 | 13 | #include <linux/sched.h> |
1da177e4 LT |
14 | #include <linux/interrupt.h> |
15 | #include <linux/kernel_stat.h> | |
3795de23 | 16 | |
a1b09501 MR |
17 | #include <asm/irq_regs.h> |
18 | ||
ad8d75ff | 19 | #include <trace/events/irq.h> |
1da177e4 LT |
20 | |
21 | #include "internals.h" | |
22 | ||
caacdbf4 PD |
23 | #ifdef CONFIG_GENERIC_IRQ_MULTI_HANDLER |
24 | void (*handle_arch_irq)(struct pt_regs *) __ro_after_init; | |
25 | #endif | |
26 | ||
6a6de9ef TG |
27 | /** |
28 | * handle_bad_irq - handle spurious and unhandled irqs | |
43a1dd50 | 29 | * @desc: description of the interrupt |
43a1dd50 HK |
30 | * |
31 | * Handles spurious and unhandled IRQ's. It also prints a debugmessage. | |
6a6de9ef | 32 | */ |
bd0b9ac4 | 33 | void handle_bad_irq(struct irq_desc *desc) |
6a6de9ef | 34 | { |
bd0b9ac4 TG |
35 | unsigned int irq = irq_desc_get_irq(desc); |
36 | ||
43f77759 | 37 | print_irq_desc(irq, desc); |
b51bf95c | 38 | kstat_incr_irqs_this_cpu(desc); |
6a6de9ef TG |
39 | ack_bad_irq(irq); |
40 | } | |
9d67dc5d | 41 | EXPORT_SYMBOL_GPL(handle_bad_irq); |
6a6de9ef | 42 | |
1da177e4 LT |
43 | /* |
44 | * Special, empty irq handler: | |
45 | */ | |
7d12e780 | 46 | irqreturn_t no_action(int cpl, void *dev_id) |
1da177e4 LT |
47 | { |
48 | return IRQ_NONE; | |
49 | } | |
d6ee6d23 | 50 | EXPORT_SYMBOL_GPL(no_action); |
1da177e4 | 51 | |
f48fe81e TG |
52 | static void warn_no_thread(unsigned int irq, struct irqaction *action) |
53 | { | |
54 | if (test_and_set_bit(IRQTF_WARNED, &action->thread_flags)) | |
55 | return; | |
56 | ||
57 | printk(KERN_WARNING "IRQ %d device %s returned IRQ_WAKE_THREAD " | |
58 | "but no thread function available.", irq, action->name); | |
59 | } | |
60 | ||
a92444c6 | 61 | void __irq_wake_thread(struct irq_desc *desc, struct irqaction *action) |
b5faba21 TG |
62 | { |
63 | /* | |
69592db2 AG |
64 | * In case the thread crashed and was killed we just pretend that |
65 | * we handled the interrupt. The hardirq handler has disabled the | |
66 | * device interrupt, so no irq storm is lurking. | |
67 | */ | |
68 | if (action->thread->flags & PF_EXITING) | |
69 | return; | |
70 | ||
71 | /* | |
72 | * Wake up the handler thread for this action. If the | |
b5faba21 TG |
73 | * RUNTHREAD bit is already set, nothing to do. |
74 | */ | |
69592db2 | 75 | if (test_and_set_bit(IRQTF_RUNTHREAD, &action->thread_flags)) |
b5faba21 TG |
76 | return; |
77 | ||
78 | /* | |
79 | * It's safe to OR the mask lockless here. We have only two | |
80 | * places which write to threads_oneshot: This code and the | |
81 | * irq thread. | |
82 | * | |
83 | * This code is the hard irq context and can never run on two | |
84 | * cpus in parallel. If it ever does we have more serious | |
85 | * problems than this bitmask. | |
86 | * | |
87 | * The irq threads of this irq which clear their "running" bit | |
88 | * in threads_oneshot are serialized via desc->lock against | |
89 | * each other and they are serialized against this code by | |
90 | * IRQS_INPROGRESS. | |
91 | * | |
92 | * Hard irq handler: | |
93 | * | |
94 | * spin_lock(desc->lock); | |
95 | * desc->state |= IRQS_INPROGRESS; | |
96 | * spin_unlock(desc->lock); | |
97 | * set_bit(IRQTF_RUNTHREAD, &action->thread_flags); | |
98 | * desc->threads_oneshot |= mask; | |
99 | * spin_lock(desc->lock); | |
100 | * desc->state &= ~IRQS_INPROGRESS; | |
101 | * spin_unlock(desc->lock); | |
102 | * | |
103 | * irq thread: | |
104 | * | |
105 | * again: | |
106 | * spin_lock(desc->lock); | |
107 | * if (desc->state & IRQS_INPROGRESS) { | |
108 | * spin_unlock(desc->lock); | |
109 | * while(desc->state & IRQS_INPROGRESS) | |
110 | * cpu_relax(); | |
111 | * goto again; | |
112 | * } | |
113 | * if (!test_bit(IRQTF_RUNTHREAD, &action->thread_flags)) | |
114 | * desc->threads_oneshot &= ~mask; | |
115 | * spin_unlock(desc->lock); | |
116 | * | |
117 | * So either the thread waits for us to clear IRQS_INPROGRESS | |
118 | * or we are waiting in the flow handler for desc->lock to be | |
119 | * released before we reach this point. The thread also checks | |
120 | * IRQTF_RUNTHREAD under desc->lock. If set it leaves | |
121 | * threads_oneshot untouched and runs the thread another time. | |
122 | */ | |
123 | desc->threads_oneshot |= action->thread_mask; | |
7140ea19 IY |
124 | |
125 | /* | |
126 | * We increment the threads_active counter in case we wake up | |
127 | * the irq thread. The irq thread decrements the counter when | |
128 | * it returns from the handler or in the exit path and wakes | |
129 | * up waiters which are stuck in synchronize_irq() when the | |
130 | * active count becomes zero. synchronize_irq() is serialized | |
131 | * against this code (hard irq handler) via IRQS_INPROGRESS | |
132 | * like the finalize_oneshot() code. See comment above. | |
133 | */ | |
134 | atomic_inc(&desc->threads_active); | |
135 | ||
b5faba21 TG |
136 | wake_up_process(action->thread); |
137 | } | |
138 | ||
edd14cfe | 139 | irqreturn_t __handle_irq_event_percpu(struct irq_desc *desc, unsigned int *flags) |
1da177e4 | 140 | { |
70433c01 | 141 | irqreturn_t retval = IRQ_NONE; |
edd14cfe | 142 | unsigned int irq = desc->irq_data.irq; |
f944b5a7 | 143 | struct irqaction *action; |
1da177e4 | 144 | |
b2d3d61a DL |
145 | record_irq_time(desc); |
146 | ||
f944b5a7 | 147 | for_each_action_of_desc(desc, action) { |
70433c01 TG |
148 | irqreturn_t res; |
149 | ||
de8f5e4f PZ |
150 | /* |
151 | * If this IRQ would be threaded under force_irqthreads, mark it so. | |
152 | */ | |
153 | if (irq_settings_can_thread(desc) && | |
154 | !(action->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))) | |
d5f744f9 | 155 | lockdep_hardirq_threaded(); |
de8f5e4f | 156 | |
af39241b | 157 | trace_irq_handler_entry(irq, action); |
70433c01 TG |
158 | res = action->handler(irq, action->dev_id); |
159 | trace_irq_handler_exit(irq, action, res); | |
3aa551c9 | 160 | |
d75f773c | 161 | if (WARN_ONCE(!irqs_disabled(),"irq %u handler %pS enabled interrupts\n", |
1204e956 | 162 | irq, action->handler)) |
b738a50a TG |
163 | local_irq_disable(); |
164 | ||
70433c01 | 165 | switch (res) { |
3aa551c9 | 166 | case IRQ_WAKE_THREAD: |
f48fe81e TG |
167 | /* |
168 | * Catch drivers which return WAKE_THREAD but | |
169 | * did not set up a thread function | |
170 | */ | |
171 | if (unlikely(!action->thread_fn)) { | |
172 | warn_no_thread(irq, action); | |
173 | break; | |
174 | } | |
175 | ||
a92444c6 | 176 | __irq_wake_thread(desc, action); |
3aa551c9 | 177 | |
df561f66 | 178 | fallthrough; /* to add to randomness */ |
3aa551c9 | 179 | case IRQ_HANDLED: |
edd14cfe | 180 | *flags |= action->flags; |
3aa551c9 TG |
181 | break; |
182 | ||
183 | default: | |
184 | break; | |
185 | } | |
186 | ||
70433c01 | 187 | retval |= res; |
570540d5 | 188 | } |
1da177e4 | 189 | |
edd14cfe KB |
190 | return retval; |
191 | } | |
192 | ||
193 | irqreturn_t handle_irq_event_percpu(struct irq_desc *desc) | |
194 | { | |
195 | irqreturn_t retval; | |
196 | unsigned int flags = 0; | |
197 | ||
198 | retval = __handle_irq_event_percpu(desc, &flags); | |
199 | ||
200 | add_interrupt_randomness(desc->irq_data.irq, flags); | |
1da177e4 | 201 | |
c2b1063e | 202 | if (!irq_settings_no_debug(desc)) |
0dcdbc97 | 203 | note_interrupt(desc, retval); |
1277a532 | 204 | return retval; |
4912609f TG |
205 | } |
206 | ||
207 | irqreturn_t handle_irq_event(struct irq_desc *desc) | |
208 | { | |
4912609f TG |
209 | irqreturn_t ret; |
210 | ||
2a0d6fb3 | 211 | desc->istate &= ~IRQS_PENDING; |
32f4125e | 212 | irqd_set(&desc->irq_data, IRQD_IRQ_INPROGRESS); |
4912609f TG |
213 | raw_spin_unlock(&desc->lock); |
214 | ||
71f64340 | 215 | ret = handle_irq_event_percpu(desc); |
4912609f TG |
216 | |
217 | raw_spin_lock(&desc->lock); | |
32f4125e | 218 | irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS); |
4912609f TG |
219 | return ret; |
220 | } | |
caacdbf4 PD |
221 | |
222 | #ifdef CONFIG_GENERIC_IRQ_MULTI_HANDLER | |
223 | int __init set_handle_irq(void (*handle_irq)(struct pt_regs *)) | |
224 | { | |
225 | if (handle_arch_irq) | |
226 | return -EBUSY; | |
227 | ||
228 | handle_arch_irq = handle_irq; | |
229 | return 0; | |
230 | } | |
a1b09501 MR |
231 | |
232 | /** | |
233 | * generic_handle_arch_irq - root irq handler for architectures which do no | |
234 | * entry accounting themselves | |
235 | * @regs: Register file coming from the low-level handling code | |
236 | */ | |
237 | asmlinkage void noinstr generic_handle_arch_irq(struct pt_regs *regs) | |
238 | { | |
239 | struct pt_regs *old_regs; | |
240 | ||
241 | irq_enter(); | |
242 | old_regs = set_irq_regs(regs); | |
243 | handle_arch_irq(regs); | |
244 | set_irq_regs(old_regs); | |
245 | irq_exit(); | |
246 | } | |
caacdbf4 | 247 | #endif |