summaryrefslogtreecommitdiffstats
path: root/kernel/rtmutex-tester.c
blob: fe211ba3a5b5df0836712fec7996b716e5b555a7 (plain)
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
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
/*
 * RT-Mutex-tester: scriptable tester for rt mutexes
 *
 * started by Thomas Gleixner:
 *
 *  Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
 *
 */
#include <linux/config.h>
#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/smp_lock.h>
#include <linux/spinlock.h>
#include <linux/sysdev.h>
#include <linux/timer.h>

#include "rtmutex.h"

#define MAX_RT_TEST_THREADS	8
#define MAX_RT_TEST_MUTEXES	8

static spinlock_t rttest_lock;
static atomic_t rttest_event;

struct test_thread_data {
	int			opcode;
	int			opdata;
	int			mutexes[MAX_RT_TEST_MUTEXES];
	int			bkl;
	int			event;
	struct sys_device	sysdev;
};

static struct test_thread_data thread_data[MAX_RT_TEST_THREADS];
static task_t *threads[MAX_RT_TEST_THREADS];
static struct rt_mutex mutexes[MAX_RT_TEST_MUTEXES];

enum test_opcodes {
	RTTEST_NOP = 0,
	RTTEST_SCHEDOT,		/* 1 Sched other, data = nice */
	RTTEST_SCHEDRT,		/* 2 Sched fifo, data = prio */
	RTTEST_LOCK,		/* 3 Lock uninterruptible, data = lockindex */
	RTTEST_LOCKNOWAIT,	/* 4 Lock uninterruptible no wait in wakeup, data = lockindex */
	RTTEST_LOCKINT,		/* 5 Lock interruptible, data = lockindex */
	RTTEST_LOCKINTNOWAIT,	/* 6 Lock interruptible no wait in wakeup, data = lockindex */
	RTTEST_LOCKCONT,	/* 7 Continue locking after the wakeup delay */
	RTTEST_UNLOCK,		/* 8 Unlock, data = lockindex */
	RTTEST_LOCKBKL, 	/* 9 Lock BKL */
	RTTEST_UNLOCKBKL,	/* 10 Unlock BKL */
	RTTEST_SIGNAL,		/* 11 Signal other test thread, data = thread id */
	RTTEST_RESETEVENT = 98,	/* 98 Reset event counter */
	RTTEST_RESET = 99,	/* 99 Reset all pending operations */
};

static int handle_op(struct test_thread_data *td, int lockwakeup)
{
	struct sched_param schedpar;
	int i, id, ret = -EINVAL;

	switch(td->opcode) {

	case RTTEST_NOP:
		return 0;

	case RTTEST_SCHEDOT:
		schedpar.sched_priority = 0;
		ret = sched_setscheduler(current, SCHED_NORMAL, &schedpar);
		if (!ret)
			set_user_nice(current, 0);
		return ret;

	case RTTEST_SCHEDRT:
		schedpar.sched_priority = td->opdata;
		return sched_setscheduler(current, SCHED_FIFO, &schedpar);

	case RTTEST_LOCKCONT:
		td->mutexes[td->opdata] = 1;
		td->event = atomic_add_return(1, &rttest_event);
		return 0;

	case RTTEST_RESET:
		for (i = 0; i < MAX_RT_TEST_MUTEXES; i++) {
			if (td->mutexes[i] == 4) {
				rt_mutex_unlock(&mutexes[i]);
				td->mutexes[i] = 0;
			}
		}

		if (!lockwakeup && td->bkl == 4) {
			unlock_kernel();
			td->bkl = 0;
		}
		return 0;

	case RTTEST_RESETEVENT:
		atomic_set(&rttest_event, 0);
		return 0;

	default:
		if (lockwakeup)
			return ret;
	}

	switch(td->opcode) {

	case RTTEST_LOCK:
	case RTTEST_LOCKNOWAIT:
		id = td->opdata;
		if (id < 0 || id >= MAX_RT_TEST_MUTEXES)
			return ret;

		td->mutexes[id] = 1;
		td->event = atomic_add_return(1, &rttest_event);
		rt_mutex_lock(&mutexes[id]);
		td->event = atomic_add_return(1, &rttest_event);
		td->mutexes[id] = 4;
		return 0;

	case RTTEST_LOCKINT:
	case RTTEST_LOCKINTNOWAIT:
		id = td->opdata;
		if (id < 0 || id >= MAX_RT_TEST_MUTEXES)
			return ret;

		td->mutexes[id] = 1;
		td->event = atomic_add_return(1, &rttest_event);
		ret = rt_mutex_lock_interruptible(&mutexes[id], 0);
		td->event = atomic_add_return(1, &rttest_event);
		td->mutexes[id] = ret ? 0 : 4;
		return ret ? -EINTR : 0;

	case RTTEST_UNLOCK:
		id = td->opdata;
		if (id < 0 || id >= MAX_RT_TEST_MUTEXES || td->mutexes[id] != 4)
			return ret;

		td->event = atomic_add_return(1, &rttest_event);
		rt_mutex_unlock(&mutexes[id]);
		td->event = atomic_add_return(1, &rttest_event);
		td->mutexes[id] = 0;
		return 0;

	case RTTEST_LOCKBKL:
		if (td->bkl)
			return 0;
		td->bkl = 1;
		lock_kernel();
		td->bkl = 4;
		return 0;

	case RTTEST_UNLOCKBKL:
		if (td->bkl != 4)
			break;
		unlock_kernel();
		td->bkl = 0;
		return 0;

	default:
		break;
	}
	return ret;
}

/*
 * Schedule replacement for rtsem_down(). Only called for threads with
 * PF_MUTEX_TESTER set.
 *
 * This allows us to have finegrained control over the event flow.
 *
 */
void schedule_rt_mutex_test(struct rt_mutex *mutex)
{
	int tid, op, dat;
	struct test_thread_data *td;

	/* We have to lookup the task */
	for (tid = 0; tid < MAX_RT_TEST_THREADS; tid++) {
		if (threads[tid] == current)
			break;
	}

	BUG_ON(tid == MAX_RT_TEST_THREADS);

	td = &thread_data[tid];

	op = td->opcode;
	dat = td->opdata;

	switch (op) {
	case RTTEST_LOCK:
	case RTTEST_LOCKINT:
	case RTTEST_LOCKNOWAIT:
	case RTTEST_LOCKINTNOWAIT:
		if (mutex != &mutexes[dat])
			break;

		if (td->mutexes[dat] != 1)
			break;

		td->mutexes[dat] = 2;
		td->event = atomic_add_return(1, &rttest_event);
		break;

	case RTTEST_LOCKBKL:
	default:
		break;
	}

	schedule();


	switch (op) {
	case RTTEST_LOCK:
	case RTTEST_LOCKINT:
		if (mutex != &mutexes[dat])
			return;

		if (td->mutexes[dat] != 2)
			return;

		td->mutexes[dat] = 3;
		td->event = atomic_add_return(1, &rttest_event);
		break;

	case RTTEST_LOCKNOWAIT:
	case RTTEST_LOCKINTNOWAIT:
		if (mutex != &mutexes[dat])
			return;

		if (td->mutexes[dat] != 2)
			return;

		td->mutexes[dat] = 1;
		td->event = atomic_add_return(1, &rttest_event);
		return;

	case RTTEST_LOCKBKL:
		return;
	default:
		return;
	}

	td->opcode = 0;

	for (;;) {
		set_current_state(TASK_INTERRUPTIBLE);

		if (td->opcode > 0) {
			int ret;

			set_current_state(TASK_RUNNING);
			ret = handle_op(td, 1);
			set_current_state(TASK_INTERRUPTIBLE);
			if (td->opcode == RTTEST_LOCKCONT)
				break;
			td->opcode = ret;
		}

		/* Wait for the next command to be executed */
		schedule();
	}

	/* Restore previous command and data */
	td->opcode = op;
	td->opdata = dat;
}

static int test_func(void *data)
{
	struct test_thread_data *td = data;
	int ret;

	current->flags |= PF_MUTEX_TESTER;
	allow_signal(SIGHUP);

	for(;;) {

		set_current_state(TASK_INTERRUPTIBLE);

		if (td->opcode > 0) {
			set_current_state(TASK_RUNNING);
			ret = handle_op(td, 0);
			set_current_state(TASK_INTERRUPTIBLE);
			td->opcode = ret;
		}

		/* Wait for the next command to be executed */
		schedule();

		if (signal_pending(current))
			flush_signals(current);

		if(kthread_should_stop())
			break;
	}
	return 0;
}

/**
 * sysfs_test_command - interface for test commands
 * @dev:	thread reference
 * @buf:	command for actual step
 * @count:	length of buffer
 *
 * command syntax:
 *
 * opcode:data
 */
static ssize_t sysfs_test_command(struct sys_device *dev, const char *buf,
				  size_t count)
{
	struct test_thread_data *td;
	char cmdbuf[32];
	int op, dat, tid;

	td = container_of(dev, struct test_thread_data, sysdev);
	tid = td->sysdev.id;

	/* strings from sysfs write are not 0 terminated! */
	if (count >= sizeof(cmdbuf))
		return -EINVAL;

	/* strip of \n: */
	if (buf[count-1] == '\n')
		count--;
	if (count < 1)
		return -EINVAL;

	memcpy(cmdbuf, buf, count);
	cmdbuf[count] = 0;

	if (sscanf(cmdbuf, "%d:%d", &op, &dat) != 2)
		return -EINVAL;

	switch (op) {
	case RTTEST_SIGNAL:
		send_sig(SIGHUP, threads[tid], 0);
		break;

	default:
		if (td->opcode > 0)
			return -EBUSY;
		td->opdata = dat;
		td->opcode = op;
		wake_up_process(threads[tid]);
	}

	return count;
}

/**
 * sysfs_test_status - sysfs interface for rt tester
 * @dev:	thread to query
 * @buf:	char buffer to be filled with thread status info
 */
static ssize_t sysfs_test_status(struct sys_device *dev, char *buf)
{
	struct test_thread_data *td;
	char *curr = buf;
	task_t *tsk;
	int i;

	td = container_of(dev, struct test_thread_data, sysdev);
	tsk = threads[td->sysdev.id];

	spin_lock(&rttest_lock);

	curr += sprintf(curr,
		"O: %4d, E:%8d, S: 0x%08lx, P: %4d, N: %4d, B: %p, K: %d, M:",
		td->opcode, td->event, tsk->state,
			(MAX_RT_PRIO - 1) - tsk->prio,
			(MAX_RT_PRIO - 1) - tsk->normal_prio,
		tsk->pi_blocked_on, td->bkl);

	for (i = MAX_RT_TEST_MUTEXES - 1; i >=0 ; i--)
		curr += sprintf(curr, "%d", td->mutexes[i]);

	spin_unlock(&rttest_lock);

	curr += sprintf(curr, ", T: %p, R: %p\n", tsk,
			mutexes[td->sysdev.id].owner);

	return curr - buf;
}

static SYSDEV_ATTR(status, 0600, sysfs_test_status, NULL);
static SYSDEV_ATTR(command, 0600, NULL, sysfs_test_command);

static struct sysdev_class rttest_sysclass = {
	set_kset_name("rttest"),
};

static int init_test_thread(int id)
{
	thread_data[id].sysdev.cls = &rttest_sysclass;
	thread_data[id].sysdev.id = id;

	threads[id] = kthread_run(test_func, &thread_data[id], "rt-test-%d", id);
	if (IS_ERR(threads[id]))
		return PTR_ERR(threads[id]);

	return sysdev_register(&thread_data[id].sysdev);
}

static int init_rttest(void)
{
	int ret, i;

	spin_lock_init(&rttest_lock);

	for (i = 0; i < MAX_RT_TEST_MUTEXES; i++)
		rt_mutex_init(&mutexes[i]);

	ret = sysdev_class_register(&rttest_sysclass);
	if (ret)
		return ret;

	for (i = 0; i < MAX_RT_TEST_THREADS; i++) {
		ret = init_test_thread(i);
		if (ret)
			break;
		ret = sysdev_create_file(&thread_data[i].sysdev, &attr_status);
		if (ret)
			break;
		ret = sysdev_create_file(&thread_data[i].sysdev, &attr_command);
		if (ret)
			break;
	}

	printk("Initializing RT-Tester: %s\n", ret ? "Failed" : "OK" );

	return ret;
}

device_initcall(init_rttest);
OpenPOWER on IntegriCloud