1 /*
2 * RT-Mutex-tester: scriptable tester for rt mutexes
3 *
4 * started by Thomas Gleixner:
5 *
6 * Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
7 *
8 */
9 #include <linux/device.h>
10 #include <linux/kthread.h>
11 #include <linux/export.h>
12 #include <linux/sched.h>
13 #include <linux/spinlock.h>
14 #include <linux/timer.h>
15 #include <linux/freezer.h>
16
17 #include "rtmutex.h"
18
19 #define MAX_RT_TEST_THREADS 8
20 #define MAX_RT_TEST_MUTEXES 8
21
22 static spinlock_t rttest_lock;
23 static atomic_t rttest_event;
24
25 struct test_thread_data {
26 int opcode;
27 int opdata;
28 int mutexes[MAX_RT_TEST_MUTEXES];
29 int event;
30 struct device dev;
31 };
32
33 static struct test_thread_data thread_data[MAX_RT_TEST_THREADS];
34 static struct task_struct *threads[MAX_RT_TEST_THREADS];
35 static struct rt_mutex mutexes[MAX_RT_TEST_MUTEXES];
36
37 enum test_opcodes {
38 RTTEST_NOP = 0,
39 RTTEST_SCHEDOT, /* 1 Sched other, data = nice */
40 RTTEST_SCHEDRT, /* 2 Sched fifo, data = prio */
41 RTTEST_LOCK, /* 3 Lock uninterruptible, data = lockindex */
42 RTTEST_LOCKNOWAIT, /* 4 Lock uninterruptible no wait in wakeup, data = lockindex */
43 RTTEST_LOCKINT, /* 5 Lock interruptible, data = lockindex */
44 RTTEST_LOCKINTNOWAIT, /* 6 Lock interruptible no wait in wakeup, data = lockindex */
45 RTTEST_LOCKCONT, /* 7 Continue locking after the wakeup delay */
46 RTTEST_UNLOCK, /* 8 Unlock, data = lockindex */
47 /* 9, 10 - reserved for BKL commemoration */
48 RTTEST_SIGNAL = 11, /* 11 Signal other test thread, data = thread id */
49 RTTEST_RESETEVENT = 98, /* 98 Reset event counter */
50 RTTEST_RESET = 99, /* 99 Reset all pending operations */
51 };
52
handle_op(struct test_thread_data * td,int lockwakeup)53 static int handle_op(struct test_thread_data *td, int lockwakeup)
54 {
55 int i, id, ret = -EINVAL;
56
57 switch(td->opcode) {
58
59 case RTTEST_NOP:
60 return 0;
61
62 case RTTEST_LOCKCONT:
63 td->mutexes[td->opdata] = 1;
64 td->event = atomic_add_return(1, &rttest_event);
65 return 0;
66
67 case RTTEST_RESET:
68 for (i = 0; i < MAX_RT_TEST_MUTEXES; i++) {
69 if (td->mutexes[i] == 4) {
70 rt_mutex_unlock(&mutexes[i]);
71 td->mutexes[i] = 0;
72 }
73 }
74 return 0;
75
76 case RTTEST_RESETEVENT:
77 atomic_set(&rttest_event, 0);
78 return 0;
79
80 default:
81 if (lockwakeup)
82 return ret;
83 }
84
85 switch(td->opcode) {
86
87 case RTTEST_LOCK:
88 case RTTEST_LOCKNOWAIT:
89 id = td->opdata;
90 if (id < 0 || id >= MAX_RT_TEST_MUTEXES)
91 return ret;
92
93 td->mutexes[id] = 1;
94 td->event = atomic_add_return(1, &rttest_event);
95 rt_mutex_lock(&mutexes[id]);
96 td->event = atomic_add_return(1, &rttest_event);
97 td->mutexes[id] = 4;
98 return 0;
99
100 case RTTEST_LOCKINT:
101 case RTTEST_LOCKINTNOWAIT:
102 id = td->opdata;
103 if (id < 0 || id >= MAX_RT_TEST_MUTEXES)
104 return ret;
105
106 td->mutexes[id] = 1;
107 td->event = atomic_add_return(1, &rttest_event);
108 ret = rt_mutex_lock_interruptible(&mutexes[id], 0);
109 td->event = atomic_add_return(1, &rttest_event);
110 td->mutexes[id] = ret ? 0 : 4;
111 return ret ? -EINTR : 0;
112
113 case RTTEST_UNLOCK:
114 id = td->opdata;
115 if (id < 0 || id >= MAX_RT_TEST_MUTEXES || td->mutexes[id] != 4)
116 return ret;
117
118 td->event = atomic_add_return(1, &rttest_event);
119 rt_mutex_unlock(&mutexes[id]);
120 td->event = atomic_add_return(1, &rttest_event);
121 td->mutexes[id] = 0;
122 return 0;
123
124 default:
125 break;
126 }
127 return ret;
128 }
129
130 /*
131 * Schedule replacement for rtsem_down(). Only called for threads with
132 * PF_MUTEX_TESTER set.
133 *
134 * This allows us to have finegrained control over the event flow.
135 *
136 */
schedule_rt_mutex_test(struct rt_mutex * mutex)137 void schedule_rt_mutex_test(struct rt_mutex *mutex)
138 {
139 int tid, op, dat;
140 struct test_thread_data *td;
141
142 /* We have to lookup the task */
143 for (tid = 0; tid < MAX_RT_TEST_THREADS; tid++) {
144 if (threads[tid] == current)
145 break;
146 }
147
148 BUG_ON(tid == MAX_RT_TEST_THREADS);
149
150 td = &thread_data[tid];
151
152 op = td->opcode;
153 dat = td->opdata;
154
155 switch (op) {
156 case RTTEST_LOCK:
157 case RTTEST_LOCKINT:
158 case RTTEST_LOCKNOWAIT:
159 case RTTEST_LOCKINTNOWAIT:
160 if (mutex != &mutexes[dat])
161 break;
162
163 if (td->mutexes[dat] != 1)
164 break;
165
166 td->mutexes[dat] = 2;
167 td->event = atomic_add_return(1, &rttest_event);
168 break;
169
170 default:
171 break;
172 }
173
174 schedule();
175
176
177 switch (op) {
178 case RTTEST_LOCK:
179 case RTTEST_LOCKINT:
180 if (mutex != &mutexes[dat])
181 return;
182
183 if (td->mutexes[dat] != 2)
184 return;
185
186 td->mutexes[dat] = 3;
187 td->event = atomic_add_return(1, &rttest_event);
188 break;
189
190 case RTTEST_LOCKNOWAIT:
191 case RTTEST_LOCKINTNOWAIT:
192 if (mutex != &mutexes[dat])
193 return;
194
195 if (td->mutexes[dat] != 2)
196 return;
197
198 td->mutexes[dat] = 1;
199 td->event = atomic_add_return(1, &rttest_event);
200 return;
201
202 default:
203 return;
204 }
205
206 td->opcode = 0;
207
208 for (;;) {
209 set_current_state(TASK_INTERRUPTIBLE);
210
211 if (td->opcode > 0) {
212 int ret;
213
214 set_current_state(TASK_RUNNING);
215 ret = handle_op(td, 1);
216 set_current_state(TASK_INTERRUPTIBLE);
217 if (td->opcode == RTTEST_LOCKCONT)
218 break;
219 td->opcode = ret;
220 }
221
222 /* Wait for the next command to be executed */
223 schedule();
224 }
225
226 /* Restore previous command and data */
227 td->opcode = op;
228 td->opdata = dat;
229 }
230
test_func(void * data)231 static int test_func(void *data)
232 {
233 struct test_thread_data *td = data;
234 int ret;
235
236 current->flags |= PF_MUTEX_TESTER;
237 set_freezable();
238 allow_signal(SIGHUP);
239
240 for(;;) {
241
242 set_current_state(TASK_INTERRUPTIBLE);
243
244 if (td->opcode > 0) {
245 set_current_state(TASK_RUNNING);
246 ret = handle_op(td, 0);
247 set_current_state(TASK_INTERRUPTIBLE);
248 td->opcode = ret;
249 }
250
251 /* Wait for the next command to be executed */
252 schedule();
253 try_to_freeze();
254
255 if (signal_pending(current))
256 flush_signals(current);
257
258 if(kthread_should_stop())
259 break;
260 }
261 return 0;
262 }
263
264 /**
265 * sysfs_test_command - interface for test commands
266 * @dev: thread reference
267 * @buf: command for actual step
268 * @count: length of buffer
269 *
270 * command syntax:
271 *
272 * opcode:data
273 */
sysfs_test_command(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)274 static ssize_t sysfs_test_command(struct device *dev, struct device_attribute *attr,
275 const char *buf, size_t count)
276 {
277 struct sched_param schedpar;
278 struct test_thread_data *td;
279 char cmdbuf[32];
280 int op, dat, tid, ret;
281
282 td = container_of(dev, struct test_thread_data, dev);
283 tid = td->dev.id;
284
285 /* strings from sysfs write are not 0 terminated! */
286 if (count >= sizeof(cmdbuf))
287 return -EINVAL;
288
289 /* strip of \n: */
290 if (buf[count-1] == '\n')
291 count--;
292 if (count < 1)
293 return -EINVAL;
294
295 memcpy(cmdbuf, buf, count);
296 cmdbuf[count] = 0;
297
298 if (sscanf(cmdbuf, "%d:%d", &op, &dat) != 2)
299 return -EINVAL;
300
301 switch (op) {
302 case RTTEST_SCHEDOT:
303 schedpar.sched_priority = 0;
304 ret = sched_setscheduler(threads[tid], SCHED_NORMAL, &schedpar);
305 if (ret)
306 return ret;
307 set_user_nice(current, 0);
308 break;
309
310 case RTTEST_SCHEDRT:
311 schedpar.sched_priority = dat;
312 ret = sched_setscheduler(threads[tid], SCHED_FIFO, &schedpar);
313 if (ret)
314 return ret;
315 break;
316
317 case RTTEST_SIGNAL:
318 send_sig(SIGHUP, threads[tid], 0);
319 break;
320
321 default:
322 if (td->opcode > 0)
323 return -EBUSY;
324 td->opdata = dat;
325 td->opcode = op;
326 wake_up_process(threads[tid]);
327 }
328
329 return count;
330 }
331
332 /**
333 * sysfs_test_status - sysfs interface for rt tester
334 * @dev: thread to query
335 * @buf: char buffer to be filled with thread status info
336 */
sysfs_test_status(struct device * dev,struct device_attribute * attr,char * buf)337 static ssize_t sysfs_test_status(struct device *dev, struct device_attribute *attr,
338 char *buf)
339 {
340 struct test_thread_data *td;
341 struct task_struct *tsk;
342 char *curr = buf;
343 int i;
344
345 td = container_of(dev, struct test_thread_data, dev);
346 tsk = threads[td->dev.id];
347
348 spin_lock(&rttest_lock);
349
350 curr += sprintf(curr,
351 "O: %4d, E:%8d, S: 0x%08lx, P: %4d, N: %4d, B: %p, M:",
352 td->opcode, td->event, tsk->state,
353 (MAX_RT_PRIO - 1) - tsk->prio,
354 (MAX_RT_PRIO - 1) - tsk->normal_prio,
355 tsk->pi_blocked_on);
356
357 for (i = MAX_RT_TEST_MUTEXES - 1; i >=0 ; i--)
358 curr += sprintf(curr, "%d", td->mutexes[i]);
359
360 spin_unlock(&rttest_lock);
361
362 curr += sprintf(curr, ", T: %p, R: %p\n", tsk,
363 mutexes[td->dev.id].owner);
364
365 return curr - buf;
366 }
367
368 static DEVICE_ATTR(status, 0600, sysfs_test_status, NULL);
369 static DEVICE_ATTR(command, 0600, NULL, sysfs_test_command);
370
371 static struct bus_type rttest_subsys = {
372 .name = "rttest",
373 .dev_name = "rttest",
374 };
375
init_test_thread(int id)376 static int init_test_thread(int id)
377 {
378 thread_data[id].dev.bus = &rttest_subsys;
379 thread_data[id].dev.id = id;
380
381 threads[id] = kthread_run(test_func, &thread_data[id], "rt-test-%d", id);
382 if (IS_ERR(threads[id]))
383 return PTR_ERR(threads[id]);
384
385 return device_register(&thread_data[id].dev);
386 }
387
init_rttest(void)388 static int init_rttest(void)
389 {
390 int ret, i;
391
392 spin_lock_init(&rttest_lock);
393
394 for (i = 0; i < MAX_RT_TEST_MUTEXES; i++)
395 rt_mutex_init(&mutexes[i]);
396
397 ret = subsys_system_register(&rttest_subsys, NULL);
398 if (ret)
399 return ret;
400
401 for (i = 0; i < MAX_RT_TEST_THREADS; i++) {
402 ret = init_test_thread(i);
403 if (ret)
404 break;
405 ret = device_create_file(&thread_data[i].dev, &dev_attr_status);
406 if (ret)
407 break;
408 ret = device_create_file(&thread_data[i].dev, &dev_attr_command);
409 if (ret)
410 break;
411 }
412
413 printk("Initializing RT-Tester: %s\n", ret ? "Failed" : "OK" );
414
415 return ret;
416 }
417
418 device_initcall(init_rttest);
419