1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
|
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
* Copyright (C) 2005-2006, Thomas Gleixner
*
* This file contains the IRQ-resend code
*
* If the interrupt is waiting to be processed, we try to re-run it.
* We can't directly run it from here since the caller might be in an
* interrupt-protected region. Not all irq controller chips can
* retrigger interrupts at the hardware level, so in those cases
* we allow the resending of IRQs via a tasklet.
*/
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/interrupt.h>
#include "internals.h"
#ifdef CONFIG_HARDIRQS_SW_RESEND
/* hlist_head to handle software resend of interrupts: */
static HLIST_HEAD(irq_resend_list);
static DEFINE_RAW_SPINLOCK(irq_resend_lock);
/*
* Run software resends of IRQ's
*/
static void resend_irqs(struct tasklet_struct *unused)
{
struct irq_desc *desc;
raw_spin_lock_irq(&irq_resend_lock);
while (!hlist_empty(&irq_resend_list)) {
desc = hlist_entry(irq_resend_list.first, struct irq_desc,
resend_node);
hlist_del_init(&desc->resend_node);
raw_spin_unlock(&irq_resend_lock);
desc->handle_irq(desc);
raw_spin_lock(&irq_resend_lock);
}
raw_spin_unlock_irq(&irq_resend_lock);
}
/* Tasklet to handle resend: */
static DECLARE_TASKLET(resend_tasklet, resend_irqs);
static int irq_sw_resend(struct irq_desc *desc)
{
/*
* Validate whether this interrupt can be safely injected from
* non interrupt context
*/
if (handle_enforce_irqctx(&desc->irq_data))
return -EINVAL;
/*
* If the interrupt is running in the thread context of the parent
* irq we need to be careful, because we cannot trigger it
* directly.
*/
if (irq_settings_is_nested_thread(desc)) {
/*
* If the parent_irq is valid, we retrigger the parent,
* otherwise we do nothing.
*/
if (!desc->parent_irq)
return -EINVAL;
}
/* Add to resend_list and activate the softirq: */
raw_spin_lock(&irq_resend_lock);
hlist_add_head(&desc->resend_node, &irq_resend_list);
raw_spin_unlock(&irq_resend_lock);
tasklet_schedule(&resend_tasklet);
return 0;
}
void clear_irq_resend(struct irq_desc *desc)
{
raw_spin_lock(&irq_resend_lock);
hlist_del_init(&desc->resend_node);
raw_spin_unlock(&irq_resend_lock);
}
void irq_resend_init(struct irq_desc *desc)
{
INIT_HLIST_NODE(&desc->resend_node);
}
#else
void clear_irq_resend(struct irq_desc *desc) {}
void irq_resend_init(struct irq_desc *desc) {}
static int irq_sw_resend(struct irq_desc *desc)
{
return -EINVAL;
}
#endif
static int try_retrigger(struct irq_desc *desc)
{
if (desc->irq_data.chip->irq_retrigger)
return desc->irq_data.chip->irq_retrigger(&desc->irq_data);
#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
return irq_chip_retrigger_hierarchy(&desc->irq_data);
#else
return 0;
#endif
}
/*
* IRQ resend
*
* Is called with interrupts disabled and desc->lock held.
*/
int check_irq_resend(struct irq_desc *desc, bool inject)
{
int err = 0;
/*
* We do not resend level type interrupts. Level type interrupts
* are resent by hardware when they are still active. Clear the
* pending bit so suspend/resume does not get confused.
*/
if (irq_settings_is_level(desc)) {
desc->istate &= ~IRQS_PENDING;
return -EINVAL;
}
if (desc->istate & IRQS_REPLAY)
return -EBUSY;
if (!(desc->istate & IRQS_PENDING) && !inject)
return 0;
desc->istate &= ~IRQS_PENDING;
if (!try_retrigger(desc))
err = irq_sw_resend(desc);
/* If the retrigger was successful, mark it with the REPLAY bit */
if (!err)
desc->istate |= IRQS_REPLAY;
return err;
}
#ifdef CONFIG_GENERIC_IRQ_INJECTION
/**
* irq_inject_interrupt - Inject an interrupt for testing/error injection
* @irq: The interrupt number
*
* This function must only be used for debug and testing purposes!
*
* Especially on x86 this can cause a premature completion of an interrupt
* affinity change causing the interrupt line to become stale. Very
* unlikely, but possible.
*
* The injection can fail for various reasons:
* - Interrupt is not activated
* - Interrupt is NMI type or currently replaying
* - Interrupt is level type
* - Interrupt does not support hardware retrigger and software resend is
* either not enabled or not possible for the interrupt.
*/
int irq_inject_interrupt(unsigned int irq)
{
struct irq_desc *desc;
unsigned long flags;
int err;
/* Try the state injection hardware interface first */
if (!irq_set_irqchip_state(irq, IRQCHIP_STATE_PENDING, true))
return 0;
/* That failed, try via the resend mechanism */
desc = irq_get_desc_buslock(irq, &flags, 0);
if (!desc)
return -EINVAL;
/*
* Only try to inject when the interrupt is:
* - not NMI type
* - activated
*/
if ((desc->istate & IRQS_NMI) || !irqd_is_activated(&desc->irq_data))
err = -EINVAL;
else
err = check_irq_resend(desc, true);
irq_put_desc_busunlock(desc, flags);
return err;
}
EXPORT_SYMBOL_GPL(irq_inject_interrupt);
#endif
|
