1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /******************************************************************************
3  *
4  *   Copyright © International Business Machines  Corp., 2006-2008
5  *
6  * DESCRIPTION
7  *      This test excercises the futex syscall op codes needed for requeuing
8  *      priority inheritance aware POSIX condition variables and mutexes.
9  *
10  * AUTHORS
11  *      Sripathi Kodi <sripathik@in.ibm.com>
12  *      Darren Hart <dvhart@linux.intel.com>
13  *
14  * HISTORY
15  *      2008-Jan-13: Initial version by Sripathi Kodi <sripathik@in.ibm.com>
16  *      2009-Nov-6: futex test adaptation by Darren Hart <dvhart@linux.intel.com>
17  *
18  *****************************************************************************/
19 
20 #include <errno.h>
21 #include <limits.h>
22 #include <pthread.h>
23 #include <stdio.h>
24 #include <stdlib.h>
25 #include <signal.h>
26 #include <string.h>
27 #include "atomic.h"
28 #include "futextest.h"
29 #include "logging.h"
30 
31 #define TEST_NAME "futex-requeue-pi"
32 #define MAX_WAKE_ITERS 1000
33 #define THREAD_MAX 10
34 #define SIGNAL_PERIOD_US 100
35 
36 atomic_t waiters_blocked = ATOMIC_INITIALIZER;
37 atomic_t waiters_woken = ATOMIC_INITIALIZER;
38 
39 futex_t f1 = FUTEX_INITIALIZER;
40 futex_t f2 = FUTEX_INITIALIZER;
41 futex_t wake_complete = FUTEX_INITIALIZER;
42 
43 /* Test option defaults */
44 static long timeout_ns;
45 static int broadcast;
46 static int owner;
47 static int locked;
48 
49 struct thread_arg {
50 	long id;
51 	struct timespec *timeout;
52 	int lock;
53 	int ret;
54 };
55 #define THREAD_ARG_INITIALIZER { 0, NULL, 0, 0 }
56 
57 void usage(char *prog)
58 {
59 	printf("Usage: %s\n", prog);
60 	printf("  -b	Broadcast wakeup (all waiters)\n");
61 	printf("  -c	Use color\n");
62 	printf("  -h	Display this help message\n");
63 	printf("  -l	Lock the pi futex across requeue\n");
64 	printf("  -o	Use a third party pi futex owner during requeue (cancels -l)\n");
65 	printf("  -t N	Timeout in nanoseconds (default: 0)\n");
66 	printf("  -v L	Verbosity level: %d=QUIET %d=CRITICAL %d=INFO\n",
67 	       VQUIET, VCRITICAL, VINFO);
68 }
69 
70 int create_rt_thread(pthread_t *pth, void*(*func)(void *), void *arg,
71 		     int policy, int prio)
72 {
73 	int ret;
74 	struct sched_param schedp;
75 	pthread_attr_t attr;
76 
77 	pthread_attr_init(&attr);
78 	memset(&schedp, 0, sizeof(schedp));
79 
80 	ret = pthread_attr_setinheritsched(&attr, PTHREAD_EXPLICIT_SCHED);
81 	if (ret) {
82 		error("pthread_attr_setinheritsched\n", ret);
83 		return -1;
84 	}
85 
86 	ret = pthread_attr_setschedpolicy(&attr, policy);
87 	if (ret) {
88 		error("pthread_attr_setschedpolicy\n", ret);
89 		return -1;
90 	}
91 
92 	schedp.sched_priority = prio;
93 	ret = pthread_attr_setschedparam(&attr, &schedp);
94 	if (ret) {
95 		error("pthread_attr_setschedparam\n", ret);
96 		return -1;
97 	}
98 
99 	ret = pthread_create(pth, &attr, func, arg);
100 	if (ret) {
101 		error("pthread_create\n", ret);
102 		return -1;
103 	}
104 	return 0;
105 }
106 
107 
108 void *waiterfn(void *arg)
109 {
110 	struct thread_arg *args = (struct thread_arg *)arg;
111 	futex_t old_val;
112 
113 	info("Waiter %ld: running\n", args->id);
114 	/* Each thread sleeps for a different amount of time
115 	 * This is to avoid races, because we don't lock the
116 	 * external mutex here */
117 	usleep(1000 * (long)args->id);
118 
119 	old_val = f1;
120 	atomic_inc(&waiters_blocked);
121 	info("Calling futex_wait_requeue_pi: %p (%u) -> %p\n",
122 	     &f1, f1, &f2);
123 	args->ret = futex_wait_requeue_pi(&f1, old_val, &f2, args->timeout,
124 					  FUTEX_PRIVATE_FLAG);
125 
126 	info("waiter %ld woke with %d %s\n", args->id, args->ret,
127 	     args->ret < 0 ? strerror(errno) : "");
128 	atomic_inc(&waiters_woken);
129 	if (args->ret < 0) {
130 		if (args->timeout && errno == ETIMEDOUT)
131 			args->ret = 0;
132 		else {
133 			args->ret = RET_ERROR;
134 			error("futex_wait_requeue_pi\n", errno);
135 		}
136 		futex_lock_pi(&f2, NULL, 0, FUTEX_PRIVATE_FLAG);
137 	}
138 	futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
139 
140 	info("Waiter %ld: exiting with %d\n", args->id, args->ret);
141 	pthread_exit((void *)&args->ret);
142 }
143 
144 void *broadcast_wakerfn(void *arg)
145 {
146 	struct thread_arg *args = (struct thread_arg *)arg;
147 	int nr_requeue = INT_MAX;
148 	int task_count = 0;
149 	futex_t old_val;
150 	int nr_wake = 1;
151 	int i = 0;
152 
153 	info("Waker: waiting for waiters to block\n");
154 	while (waiters_blocked.val < THREAD_MAX)
155 		usleep(1000);
156 	usleep(1000);
157 
158 	info("Waker: Calling broadcast\n");
159 	if (args->lock) {
160 		info("Calling FUTEX_LOCK_PI on mutex=%x @ %p\n", f2, &f2);
161 		futex_lock_pi(&f2, NULL, 0, FUTEX_PRIVATE_FLAG);
162 	}
163  continue_requeue:
164 	old_val = f1;
165 	args->ret = futex_cmp_requeue_pi(&f1, old_val, &f2, nr_wake, nr_requeue,
166 				   FUTEX_PRIVATE_FLAG);
167 	if (args->ret < 0) {
168 		args->ret = RET_ERROR;
169 		error("FUTEX_CMP_REQUEUE_PI failed\n", errno);
170 	} else if (++i < MAX_WAKE_ITERS) {
171 		task_count += args->ret;
172 		if (task_count < THREAD_MAX - waiters_woken.val)
173 			goto continue_requeue;
174 	} else {
175 		error("max broadcast iterations (%d) reached with %d/%d tasks woken or requeued\n",
176 		       0, MAX_WAKE_ITERS, task_count, THREAD_MAX);
177 		args->ret = RET_ERROR;
178 	}
179 
180 	futex_wake(&wake_complete, 1, FUTEX_PRIVATE_FLAG);
181 
182 	if (args->lock)
183 		futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
184 
185 	if (args->ret > 0)
186 		args->ret = task_count;
187 
188 	info("Waker: exiting with %d\n", args->ret);
189 	pthread_exit((void *)&args->ret);
190 }
191 
192 void *signal_wakerfn(void *arg)
193 {
194 	struct thread_arg *args = (struct thread_arg *)arg;
195 	unsigned int old_val;
196 	int nr_requeue = 0;
197 	int task_count = 0;
198 	int nr_wake = 1;
199 	int i = 0;
200 
201 	info("Waker: waiting for waiters to block\n");
202 	while (waiters_blocked.val < THREAD_MAX)
203 		usleep(1000);
204 	usleep(1000);
205 
206 	while (task_count < THREAD_MAX && waiters_woken.val < THREAD_MAX) {
207 		info("task_count: %d, waiters_woken: %d\n",
208 		     task_count, waiters_woken.val);
209 		if (args->lock) {
210 			info("Calling FUTEX_LOCK_PI on mutex=%x @ %p\n",
211 			     f2, &f2);
212 			futex_lock_pi(&f2, NULL, 0, FUTEX_PRIVATE_FLAG);
213 		}
214 		info("Waker: Calling signal\n");
215 		/* cond_signal */
216 		old_val = f1;
217 		args->ret = futex_cmp_requeue_pi(&f1, old_val, &f2,
218 						 nr_wake, nr_requeue,
219 						 FUTEX_PRIVATE_FLAG);
220 		if (args->ret < 0)
221 			args->ret = -errno;
222 		info("futex: %x\n", f2);
223 		if (args->lock) {
224 			info("Calling FUTEX_UNLOCK_PI on mutex=%x @ %p\n",
225 			     f2, &f2);
226 			futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
227 		}
228 		info("futex: %x\n", f2);
229 		if (args->ret < 0) {
230 			error("FUTEX_CMP_REQUEUE_PI failed\n", errno);
231 			args->ret = RET_ERROR;
232 			break;
233 		}
234 
235 		task_count += args->ret;
236 		usleep(SIGNAL_PERIOD_US);
237 		i++;
238 		/* we have to loop at least THREAD_MAX times */
239 		if (i > MAX_WAKE_ITERS + THREAD_MAX) {
240 			error("max signaling iterations (%d) reached, giving up on pending waiters.\n",
241 			      0, MAX_WAKE_ITERS + THREAD_MAX);
242 			args->ret = RET_ERROR;
243 			break;
244 		}
245 	}
246 
247 	futex_wake(&wake_complete, 1, FUTEX_PRIVATE_FLAG);
248 
249 	if (args->ret >= 0)
250 		args->ret = task_count;
251 
252 	info("Waker: exiting with %d\n", args->ret);
253 	info("Waker: waiters_woken: %d\n", waiters_woken.val);
254 	pthread_exit((void *)&args->ret);
255 }
256 
257 void *third_party_blocker(void *arg)
258 {
259 	struct thread_arg *args = (struct thread_arg *)arg;
260 	int ret2 = 0;
261 
262 	args->ret = futex_lock_pi(&f2, NULL, 0, FUTEX_PRIVATE_FLAG);
263 	if (args->ret)
264 		goto out;
265 	args->ret = futex_wait(&wake_complete, wake_complete, NULL,
266 			       FUTEX_PRIVATE_FLAG);
267 	ret2 = futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
268 
269  out:
270 	if (args->ret || ret2) {
271 		error("third_party_blocker() futex error", 0);
272 		args->ret = RET_ERROR;
273 	}
274 
275 	pthread_exit((void *)&args->ret);
276 }
277 
278 int unit_test(int broadcast, long lock, int third_party_owner, long timeout_ns)
279 {
280 	void *(*wakerfn)(void *) = signal_wakerfn;
281 	struct thread_arg blocker_arg = THREAD_ARG_INITIALIZER;
282 	struct thread_arg waker_arg = THREAD_ARG_INITIALIZER;
283 	pthread_t waiter[THREAD_MAX], waker, blocker;
284 	struct timespec ts, *tsp = NULL;
285 	struct thread_arg args[THREAD_MAX];
286 	int *waiter_ret;
287 	int i, ret = RET_PASS;
288 
289 	if (timeout_ns) {
290 		time_t secs;
291 
292 		info("timeout_ns = %ld\n", timeout_ns);
293 		ret = clock_gettime(CLOCK_MONOTONIC, &ts);
294 		secs = (ts.tv_nsec + timeout_ns) / 1000000000;
295 		ts.tv_nsec = ((int64_t)ts.tv_nsec + timeout_ns) % 1000000000;
296 		ts.tv_sec += secs;
297 		info("ts.tv_sec  = %ld\n", ts.tv_sec);
298 		info("ts.tv_nsec = %ld\n", ts.tv_nsec);
299 		tsp = &ts;
300 	}
301 
302 	if (broadcast)
303 		wakerfn = broadcast_wakerfn;
304 
305 	if (third_party_owner) {
306 		if (create_rt_thread(&blocker, third_party_blocker,
307 				     (void *)&blocker_arg, SCHED_FIFO, 1)) {
308 			error("Creating third party blocker thread failed\n",
309 			      errno);
310 			ret = RET_ERROR;
311 			goto out;
312 		}
313 	}
314 
315 	atomic_set(&waiters_woken, 0);
316 	for (i = 0; i < THREAD_MAX; i++) {
317 		args[i].id = i;
318 		args[i].timeout = tsp;
319 		info("Starting thread %d\n", i);
320 		if (create_rt_thread(&waiter[i], waiterfn, (void *)&args[i],
321 				     SCHED_FIFO, 1)) {
322 			error("Creating waiting thread failed\n", errno);
323 			ret = RET_ERROR;
324 			goto out;
325 		}
326 	}
327 	waker_arg.lock = lock;
328 	if (create_rt_thread(&waker, wakerfn, (void *)&waker_arg,
329 			     SCHED_FIFO, 1)) {
330 		error("Creating waker thread failed\n", errno);
331 		ret = RET_ERROR;
332 		goto out;
333 	}
334 
335 	/* Wait for threads to finish */
336 	/* Store the first error or failure encountered in waiter_ret */
337 	waiter_ret = &args[0].ret;
338 	for (i = 0; i < THREAD_MAX; i++)
339 		pthread_join(waiter[i],
340 			     *waiter_ret ? NULL : (void **)&waiter_ret);
341 
342 	if (third_party_owner)
343 		pthread_join(blocker, NULL);
344 	pthread_join(waker, NULL);
345 
346 out:
347 	if (!ret) {
348 		if (*waiter_ret)
349 			ret = *waiter_ret;
350 		else if (waker_arg.ret < 0)
351 			ret = waker_arg.ret;
352 		else if (blocker_arg.ret)
353 			ret = blocker_arg.ret;
354 	}
355 
356 	return ret;
357 }
358 
359 int main(int argc, char *argv[])
360 {
361 	int c, ret;
362 
363 	while ((c = getopt(argc, argv, "bchlot:v:")) != -1) {
364 		switch (c) {
365 		case 'b':
366 			broadcast = 1;
367 			break;
368 		case 'c':
369 			log_color(1);
370 			break;
371 		case 'h':
372 			usage(basename(argv[0]));
373 			exit(0);
374 		case 'l':
375 			locked = 1;
376 			break;
377 		case 'o':
378 			owner = 1;
379 			locked = 0;
380 			break;
381 		case 't':
382 			timeout_ns = atoi(optarg);
383 			break;
384 		case 'v':
385 			log_verbosity(atoi(optarg));
386 			break;
387 		default:
388 			usage(basename(argv[0]));
389 			exit(1);
390 		}
391 	}
392 
393 	ksft_print_header();
394 	ksft_set_plan(1);
395 	ksft_print_msg("%s: Test requeue functionality\n", basename(argv[0]));
396 	ksft_print_msg(
397 		"\tArguments: broadcast=%d locked=%d owner=%d timeout=%ldns\n",
398 		broadcast, locked, owner, timeout_ns);
399 
400 	/*
401 	 * FIXME: unit_test is obsolete now that we parse options and the
402 	 * various style of runs are done by run.sh - simplify the code and move
403 	 * unit_test into main()
404 	 */
405 	ret = unit_test(broadcast, locked, owner, timeout_ns);
406 
407 	print_result(TEST_NAME, ret);
408 	return ret;
409 }
410