1// SPDX-License-Identifier: GPL-2.0
2#include <linux/init.h>
3#include <linux/kthread.h>
4#include <linux/hrtimer.h>
5#include <linux/fs.h>
6#include <linux/debugfs.h>
7#include <linux/export.h>
8#include <linux/spinlock.h>
9#include <asm/debug.h>
10
11static int ss_get(void *data, u64 *val)
12{
13	ktime_t start, finish;
14	int loops;
15	int cont;
16	DEFINE_RAW_SPINLOCK(ss_spin);
17
18	loops = 1000000;
19	cont = 1;
20
21	start = ktime_get();
22
23	while (cont) {
24		raw_spin_lock(&ss_spin);
25		loops--;
26		if (loops == 0)
27			cont = 0;
28		raw_spin_unlock(&ss_spin);
29	}
30
31	finish = ktime_get();
32
33	*val = ktime_us_delta(finish, start);
34
35	return 0;
36}
37
38DEFINE_DEBUGFS_ATTRIBUTE(fops_ss, ss_get, NULL, "%llu\n");
39
40
41
42struct spin_multi_state {
43	raw_spinlock_t lock;
44	atomic_t start_wait;
45	atomic_t enter_wait;
46	atomic_t exit_wait;
47	int loops;
48};
49
50struct spin_multi_per_thread {
51	struct spin_multi_state *state;
52	ktime_t start;
53};
54
55static int multi_other(void *data)
56{
57	int loops;
58	int cont;
59	struct spin_multi_per_thread *pt = data;
60	struct spin_multi_state *s = pt->state;
61
62	loops = s->loops;
63	cont = 1;
64
65	atomic_dec(&s->enter_wait);
66
67	while (atomic_read(&s->enter_wait))
68		; /* spin */
69
70	pt->start = ktime_get();
71
72	atomic_dec(&s->start_wait);
73
74	while (atomic_read(&s->start_wait))
75		; /* spin */
76
77	while (cont) {
78		raw_spin_lock(&s->lock);
79		loops--;
80		if (loops == 0)
81			cont = 0;
82		raw_spin_unlock(&s->lock);
83	}
84
85	atomic_dec(&s->exit_wait);
86	while (atomic_read(&s->exit_wait))
87		; /* spin */
88	return 0;
89}
90
91static int multi_get(void *data, u64 *val)
92{
93	ktime_t finish;
94	struct spin_multi_state ms;
95	struct spin_multi_per_thread t1, t2;
96
97	ms.lock = __RAW_SPIN_LOCK_UNLOCKED("multi_get");
98	ms.loops = 1000000;
99
100	atomic_set(&ms.start_wait, 2);
101	atomic_set(&ms.enter_wait, 2);
102	atomic_set(&ms.exit_wait, 2);
103	t1.state = &ms;
104	t2.state = &ms;
105
106	kthread_run(multi_other, &t2, "multi_get");
107
108	multi_other(&t1);
109
110	finish = ktime_get();
111
112	*val = ktime_us_delta(finish, t1.start);
113
114	return 0;
115}
116
117DEFINE_DEBUGFS_ATTRIBUTE(fops_multi, multi_get, NULL, "%llu\n");
118
119static int __init spinlock_test(void)
120{
121	debugfs_create_file_unsafe("spin_single", S_IRUGO, mips_debugfs_dir, NULL,
122			    &fops_ss);
123	debugfs_create_file_unsafe("spin_multi", S_IRUGO, mips_debugfs_dir, NULL,
124			    &fops_multi);
125	return 0;
126}
127device_initcall(spinlock_test);
128