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
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
|
/*
* Common functions for in-kernel torture tests.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, you can access it online at
* http://www.gnu.org/licenses/gpl-2.0.html.
*
* Copyright (C) IBM Corporation, 2014
*
* Author: Paul E. McKenney <paulmck@us.ibm.com>
* Based on kernel/rcu/torture.c.
*/
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kthread.h>
#include <linux/err.h>
#include <linux/spinlock.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <linux/atomic.h>
#include <linux/bitops.h>
#include <linux/completion.h>
#include <linux/moduleparam.h>
#include <linux/percpu.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/freezer.h>
#include <linux/cpu.h>
#include <linux/delay.h>
#include <linux/stat.h>
#include <linux/slab.h>
#include <linux/trace_clock.h>
#include <asm/byteorder.h>
#include <linux/torture.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com>");
int fullstop = FULLSTOP_RMMOD;
EXPORT_SYMBOL_GPL(fullstop);
DEFINE_MUTEX(fullstop_mutex);
EXPORT_SYMBOL_GPL(fullstop_mutex);
#define TORTURE_RANDOM_MULT 39916801 /* prime */
#define TORTURE_RANDOM_ADD 479001701 /* prime */
#define TORTURE_RANDOM_REFRESH 10000
/*
* Crude but fast random-number generator. Uses a linear congruential
* generator, with occasional help from cpu_clock().
*/
unsigned long
torture_random(struct torture_random_state *trsp)
{
if (--trsp->trs_count < 0) {
trsp->trs_state += (unsigned long)local_clock();
trsp->trs_count = TORTURE_RANDOM_REFRESH;
}
trsp->trs_state = trsp->trs_state * TORTURE_RANDOM_MULT +
TORTURE_RANDOM_ADD;
return swahw32(trsp->trs_state);
}
EXPORT_SYMBOL_GPL(torture_random);
/*
* Variables for shuffling. The idea is to ensure that each CPU stays
* idle for an extended period to test interactions with dyntick idle,
* as well as interactions with any per-CPU varibles.
*/
struct shuffle_task {
struct list_head st_l;
struct task_struct *st_t;
};
static long shuffle_interval; /* In jiffies. */
static struct task_struct *shuffler_task;
static cpumask_var_t shuffle_tmp_mask;
static int shuffle_idle_cpu; /* Force all torture tasks off this CPU */
static struct list_head shuffle_task_list = LIST_HEAD_INIT(shuffle_task_list);
static DEFINE_MUTEX(shuffle_task_mutex);
/*
* Register a task to be shuffled. If there is no memory, just splat
* and don't bother registering.
*/
void torture_shuffle_task_register(struct task_struct *tp)
{
struct shuffle_task *stp;
if (WARN_ON_ONCE(tp == NULL))
return;
stp = kmalloc(sizeof(*stp), GFP_KERNEL);
if (WARN_ON_ONCE(stp == NULL))
return;
stp->st_t = tp;
mutex_lock(&shuffle_task_mutex);
list_add(&stp->st_l, &shuffle_task_list);
mutex_unlock(&shuffle_task_mutex);
}
EXPORT_SYMBOL_GPL(torture_shuffle_task_register);
/*
* Unregister all tasks, for example, at the end of the torture run.
*/
static void torture_shuffle_task_unregister_all(void)
{
struct shuffle_task *stp;
struct shuffle_task *p;
mutex_lock(&shuffle_task_mutex);
list_for_each_entry_safe(stp, p, &shuffle_task_list, st_l) {
list_del(&stp->st_l);
kfree(stp);
}
mutex_unlock(&shuffle_task_mutex);
}
/* Shuffle tasks such that we allow shuffle_idle_cpu to become idle.
* A special case is when shuffle_idle_cpu = -1, in which case we allow
* the tasks to run on all CPUs.
*/
static void torture_shuffle_tasks(void)
{
struct shuffle_task *stp;
cpumask_setall(shuffle_tmp_mask);
get_online_cpus();
/* No point in shuffling if there is only one online CPU (ex: UP) */
if (num_online_cpus() == 1) {
put_online_cpus();
return;
}
/* Advance to the next CPU. Upon overflow, don't idle any CPUs. */
shuffle_idle_cpu = cpumask_next(shuffle_idle_cpu, shuffle_tmp_mask);
if (shuffle_idle_cpu >= nr_cpu_ids)
shuffle_idle_cpu = -1;
if (shuffle_idle_cpu != -1) {
cpumask_clear_cpu(shuffle_idle_cpu, shuffle_tmp_mask);
if (cpumask_empty(shuffle_tmp_mask)) {
put_online_cpus();
return;
}
}
mutex_lock(&shuffle_task_mutex);
list_for_each_entry(stp, &shuffle_task_list, st_l)
set_cpus_allowed_ptr(stp->st_t, shuffle_tmp_mask);
mutex_unlock(&shuffle_task_mutex);
put_online_cpus();
}
/* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
* system to become idle at a time and cut off its timer ticks. This is meant
* to test the support for such tickless idle CPU in RCU.
*/
static int torture_shuffle(void *arg)
{
VERBOSE_TOROUT_STRING("torture_shuffle task started");
do {
schedule_timeout_interruptible(shuffle_interval);
torture_shuffle_tasks();
torture_shutdown_absorb("torture_shuffle");
} while (!torture_must_stop());
VERBOSE_TOROUT_STRING("torture_shuffle task stopping");
return 0;
}
/*
* Start the shuffler, with shuffint in jiffies.
*/
int torture_shuffle_init(long shuffint)
{
int ret;
shuffle_interval = shuffint;
shuffle_idle_cpu = -1;
if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) {
VERBOSE_TOROUT_ERRSTRING("Failed to alloc mask");
return -ENOMEM;
}
/* Create the shuffler thread */
shuffler_task = kthread_run(torture_shuffle, NULL, "torture_shuffle");
if (IS_ERR(shuffler_task)) {
ret = PTR_ERR(shuffler_task);
free_cpumask_var(shuffle_tmp_mask);
VERBOSE_TOROUT_ERRSTRING("Failed to create shuffler");
shuffler_task = NULL;
return ret;
}
torture_shuffle_task_register(shuffler_task);
return 0;
}
EXPORT_SYMBOL_GPL(torture_shuffle_init);
/*
* Stop the shuffling.
*/
void torture_shuffle_cleanup(void)
{
torture_shuffle_task_unregister_all();
if (shuffler_task) {
VERBOSE_TOROUT_STRING("Stopping torture_shuffle task");
kthread_stop(shuffler_task);
free_cpumask_var(shuffle_tmp_mask);
}
shuffler_task = NULL;
}
EXPORT_SYMBOL_GPL(torture_shuffle_cleanup);
/*
* Absorb kthreads into a kernel function that won't return, so that
* they won't ever access module text or data again.
*/
void torture_shutdown_absorb(const char *title)
{
while (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
pr_notice(
"torture thread %s parking due to system shutdown\n",
title);
schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
}
}
EXPORT_SYMBOL_GPL(torture_shutdown_absorb);
|
