1 /*-
2 * Copyright (c) 2017 Hans Petter Selasky
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice unmodified, this list of conditions, and the following
10 * disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27 #include <sys/cdefs.h>
28 #include <linux/compat.h>
29 #include <linux/kthread.h>
30 #include <linux/sched.h>
31 #include <linux/wait.h>
32
33 #include <sys/bus.h>
34 #include <sys/interrupt.h>
35 #include <sys/priority.h>
36
37 enum {
38 KTHREAD_SHOULD_STOP_MASK = (1 << 0),
39 KTHREAD_SHOULD_PARK_MASK = (1 << 1),
40 KTHREAD_IS_PARKED_MASK = (1 << 2),
41 };
42
43 bool
linux_kthread_should_stop_task(struct task_struct * task)44 linux_kthread_should_stop_task(struct task_struct *task)
45 {
46
47 return (atomic_read(&task->kthread_flags) & KTHREAD_SHOULD_STOP_MASK);
48 }
49
50 bool
linux_kthread_should_stop(void)51 linux_kthread_should_stop(void)
52 {
53
54 return (atomic_read(¤t->kthread_flags) & KTHREAD_SHOULD_STOP_MASK);
55 }
56
57 int
linux_kthread_stop(struct task_struct * task)58 linux_kthread_stop(struct task_struct *task)
59 {
60 int retval;
61
62 /*
63 * Assume task is still alive else caller should not call
64 * kthread_stop():
65 */
66 atomic_or(KTHREAD_SHOULD_STOP_MASK, &task->kthread_flags);
67 kthread_unpark(task);
68 wake_up_process(task);
69 wait_for_completion(&task->exited);
70
71 /*
72 * Get return code and free task structure:
73 */
74 retval = task->task_ret;
75 put_task_struct(task);
76
77 return (retval);
78 }
79
80 int
linux_kthread_park(struct task_struct * task)81 linux_kthread_park(struct task_struct *task)
82 {
83
84 atomic_or(KTHREAD_SHOULD_PARK_MASK, &task->kthread_flags);
85 wake_up_process(task);
86 wait_for_completion(&task->parked);
87 return (0);
88 }
89
90 void
linux_kthread_parkme(void)91 linux_kthread_parkme(void)
92 {
93 struct task_struct *task;
94
95 task = current;
96 set_task_state(task, TASK_PARKED | TASK_UNINTERRUPTIBLE);
97 while (linux_kthread_should_park()) {
98 while ((atomic_fetch_or(KTHREAD_IS_PARKED_MASK,
99 &task->kthread_flags) & KTHREAD_IS_PARKED_MASK) == 0)
100 complete(&task->parked);
101 schedule();
102 set_task_state(task, TASK_PARKED | TASK_UNINTERRUPTIBLE);
103 }
104 atomic_andnot(KTHREAD_IS_PARKED_MASK, &task->kthread_flags);
105 set_task_state(task, TASK_RUNNING);
106 }
107
108 bool
linux_kthread_should_park(void)109 linux_kthread_should_park(void)
110 {
111 struct task_struct *task;
112
113 task = current;
114 return (atomic_read(&task->kthread_flags) & KTHREAD_SHOULD_PARK_MASK);
115 }
116
117 void
linux_kthread_unpark(struct task_struct * task)118 linux_kthread_unpark(struct task_struct *task)
119 {
120
121 atomic_andnot(KTHREAD_SHOULD_PARK_MASK, &task->kthread_flags);
122 if ((atomic_fetch_andnot(KTHREAD_IS_PARKED_MASK, &task->kthread_flags) &
123 KTHREAD_IS_PARKED_MASK) != 0)
124 wake_up_state(task, TASK_PARKED);
125 }
126
127 struct task_struct *
linux_kthread_setup_and_run(struct thread * td,linux_task_fn_t * task_fn,void * arg)128 linux_kthread_setup_and_run(struct thread *td, linux_task_fn_t *task_fn, void *arg)
129 {
130 struct task_struct *task;
131
132 linux_set_current(td);
133
134 task = td->td_lkpi_task;
135 task->task_fn = task_fn;
136 task->task_data = arg;
137
138 thread_lock(td);
139 /* make sure the scheduler priority is raised */
140 sched_prio(td, PI_SWI(SWI_NET));
141 /* put thread into run-queue */
142 sched_add(td, SRQ_BORING);
143
144 return (task);
145 }
146
147 void
linux_kthread_fn(void * arg __unused)148 linux_kthread_fn(void *arg __unused)
149 {
150 struct task_struct *task = current;
151
152 if (linux_kthread_should_stop_task(task) == 0)
153 task->task_ret = task->task_fn(task->task_data);
154
155 if (linux_kthread_should_stop_task(task) != 0) {
156 struct thread *td = curthread;
157
158 /* let kthread_stop() free data */
159 td->td_lkpi_task = NULL;
160
161 /* wakeup kthread_stop() */
162 complete(&task->exited);
163 }
164 kthread_exit();
165 }
166
167 void
lkpi_kthread_work_fn(void * context,int pending __unused)168 lkpi_kthread_work_fn(void *context, int pending __unused)
169 {
170 struct kthread_work *work = context;
171
172 work->func(work);
173 }
174
175 void
lkpi_kthread_worker_init_fn(void * context,int pending __unused)176 lkpi_kthread_worker_init_fn(void *context, int pending __unused)
177 {
178 struct kthread_worker *worker = context;
179
180 worker->task = current;
181 }
182