xref: /linux/tools/testing/selftests/rseq/param_test.c (revision 4b660dbd9ee2059850fd30e0df420ca7a38a1856)
1 // SPDX-License-Identifier: LGPL-2.1
2 #define _GNU_SOURCE
3 #include <assert.h>
4 #include <linux/membarrier.h>
5 #include <pthread.h>
6 #include <sched.h>
7 #include <stdatomic.h>
8 #include <stdint.h>
9 #include <stdio.h>
10 #include <stdlib.h>
11 #include <string.h>
12 #include <syscall.h>
13 #include <unistd.h>
14 #include <poll.h>
15 #include <sys/types.h>
16 #include <signal.h>
17 #include <errno.h>
18 #include <stddef.h>
19 #include <stdbool.h>
20 
21 static inline pid_t rseq_gettid(void)
22 {
23 	return syscall(__NR_gettid);
24 }
25 
26 #define NR_INJECT	9
27 static int loop_cnt[NR_INJECT + 1];
28 
29 static int loop_cnt_1 asm("asm_loop_cnt_1") __attribute__((used));
30 static int loop_cnt_2 asm("asm_loop_cnt_2") __attribute__((used));
31 static int loop_cnt_3 asm("asm_loop_cnt_3") __attribute__((used));
32 static int loop_cnt_4 asm("asm_loop_cnt_4") __attribute__((used));
33 static int loop_cnt_5 asm("asm_loop_cnt_5") __attribute__((used));
34 static int loop_cnt_6 asm("asm_loop_cnt_6") __attribute__((used));
35 
36 static int opt_modulo, verbose;
37 
38 static int opt_yield, opt_signal, opt_sleep,
39 		opt_disable_rseq, opt_threads = 200,
40 		opt_disable_mod = 0, opt_test = 's';
41 
42 static long long opt_reps = 5000;
43 
44 static __thread __attribute__((tls_model("initial-exec")))
45 unsigned int signals_delivered;
46 
47 #ifndef BENCHMARK
48 
49 static __thread __attribute__((tls_model("initial-exec"), unused))
50 unsigned int yield_mod_cnt, nr_abort;
51 
52 #define printf_verbose(fmt, ...)			\
53 	do {						\
54 		if (verbose)				\
55 			printf(fmt, ## __VA_ARGS__);	\
56 	} while (0)
57 
58 #ifdef __i386__
59 
60 #define INJECT_ASM_REG	"eax"
61 
62 #define RSEQ_INJECT_CLOBBER \
63 	, INJECT_ASM_REG
64 
65 #define RSEQ_INJECT_ASM(n) \
66 	"mov asm_loop_cnt_" #n ", %%" INJECT_ASM_REG "\n\t" \
67 	"test %%" INJECT_ASM_REG ",%%" INJECT_ASM_REG "\n\t" \
68 	"jz 333f\n\t" \
69 	"222:\n\t" \
70 	"dec %%" INJECT_ASM_REG "\n\t" \
71 	"jnz 222b\n\t" \
72 	"333:\n\t"
73 
74 #elif defined(__x86_64__)
75 
76 #define INJECT_ASM_REG_P	"rax"
77 #define INJECT_ASM_REG		"eax"
78 
79 #define RSEQ_INJECT_CLOBBER \
80 	, INJECT_ASM_REG_P \
81 	, INJECT_ASM_REG
82 
83 #define RSEQ_INJECT_ASM(n) \
84 	"lea asm_loop_cnt_" #n "(%%rip), %%" INJECT_ASM_REG_P "\n\t" \
85 	"mov (%%" INJECT_ASM_REG_P "), %%" INJECT_ASM_REG "\n\t" \
86 	"test %%" INJECT_ASM_REG ",%%" INJECT_ASM_REG "\n\t" \
87 	"jz 333f\n\t" \
88 	"222:\n\t" \
89 	"dec %%" INJECT_ASM_REG "\n\t" \
90 	"jnz 222b\n\t" \
91 	"333:\n\t"
92 
93 #elif defined(__s390__)
94 
95 #define RSEQ_INJECT_INPUT \
96 	, [loop_cnt_1]"m"(loop_cnt[1]) \
97 	, [loop_cnt_2]"m"(loop_cnt[2]) \
98 	, [loop_cnt_3]"m"(loop_cnt[3]) \
99 	, [loop_cnt_4]"m"(loop_cnt[4]) \
100 	, [loop_cnt_5]"m"(loop_cnt[5]) \
101 	, [loop_cnt_6]"m"(loop_cnt[6])
102 
103 #define INJECT_ASM_REG	"r12"
104 
105 #define RSEQ_INJECT_CLOBBER \
106 	, INJECT_ASM_REG
107 
108 #define RSEQ_INJECT_ASM(n) \
109 	"l %%" INJECT_ASM_REG ", %[loop_cnt_" #n "]\n\t" \
110 	"ltr %%" INJECT_ASM_REG ", %%" INJECT_ASM_REG "\n\t" \
111 	"je 333f\n\t" \
112 	"222:\n\t" \
113 	"ahi %%" INJECT_ASM_REG ", -1\n\t" \
114 	"jnz 222b\n\t" \
115 	"333:\n\t"
116 
117 #elif defined(__ARMEL__)
118 
119 #define RSEQ_INJECT_INPUT \
120 	, [loop_cnt_1]"m"(loop_cnt[1]) \
121 	, [loop_cnt_2]"m"(loop_cnt[2]) \
122 	, [loop_cnt_3]"m"(loop_cnt[3]) \
123 	, [loop_cnt_4]"m"(loop_cnt[4]) \
124 	, [loop_cnt_5]"m"(loop_cnt[5]) \
125 	, [loop_cnt_6]"m"(loop_cnt[6])
126 
127 #define INJECT_ASM_REG	"r4"
128 
129 #define RSEQ_INJECT_CLOBBER \
130 	, INJECT_ASM_REG
131 
132 #define RSEQ_INJECT_ASM(n) \
133 	"ldr " INJECT_ASM_REG ", %[loop_cnt_" #n "]\n\t" \
134 	"cmp " INJECT_ASM_REG ", #0\n\t" \
135 	"beq 333f\n\t" \
136 	"222:\n\t" \
137 	"subs " INJECT_ASM_REG ", #1\n\t" \
138 	"bne 222b\n\t" \
139 	"333:\n\t"
140 
141 #elif defined(__AARCH64EL__)
142 
143 #define RSEQ_INJECT_INPUT \
144 	, [loop_cnt_1] "Qo" (loop_cnt[1]) \
145 	, [loop_cnt_2] "Qo" (loop_cnt[2]) \
146 	, [loop_cnt_3] "Qo" (loop_cnt[3]) \
147 	, [loop_cnt_4] "Qo" (loop_cnt[4]) \
148 	, [loop_cnt_5] "Qo" (loop_cnt[5]) \
149 	, [loop_cnt_6] "Qo" (loop_cnt[6])
150 
151 #define INJECT_ASM_REG	RSEQ_ASM_TMP_REG32
152 
153 #define RSEQ_INJECT_ASM(n) \
154 	"	ldr	" INJECT_ASM_REG ", %[loop_cnt_" #n "]\n"	\
155 	"	cbz	" INJECT_ASM_REG ", 333f\n"			\
156 	"222:\n"							\
157 	"	sub	" INJECT_ASM_REG ", " INJECT_ASM_REG ", #1\n"	\
158 	"	cbnz	" INJECT_ASM_REG ", 222b\n"			\
159 	"333:\n"
160 
161 #elif defined(__PPC__)
162 
163 #define RSEQ_INJECT_INPUT \
164 	, [loop_cnt_1]"m"(loop_cnt[1]) \
165 	, [loop_cnt_2]"m"(loop_cnt[2]) \
166 	, [loop_cnt_3]"m"(loop_cnt[3]) \
167 	, [loop_cnt_4]"m"(loop_cnt[4]) \
168 	, [loop_cnt_5]"m"(loop_cnt[5]) \
169 	, [loop_cnt_6]"m"(loop_cnt[6])
170 
171 #define INJECT_ASM_REG	"r18"
172 
173 #define RSEQ_INJECT_CLOBBER \
174 	, INJECT_ASM_REG
175 
176 #define RSEQ_INJECT_ASM(n) \
177 	"lwz %%" INJECT_ASM_REG ", %[loop_cnt_" #n "]\n\t" \
178 	"cmpwi %%" INJECT_ASM_REG ", 0\n\t" \
179 	"beq 333f\n\t" \
180 	"222:\n\t" \
181 	"subic. %%" INJECT_ASM_REG ", %%" INJECT_ASM_REG ", 1\n\t" \
182 	"bne 222b\n\t" \
183 	"333:\n\t"
184 
185 #elif defined(__mips__)
186 
187 #define RSEQ_INJECT_INPUT \
188 	, [loop_cnt_1]"m"(loop_cnt[1]) \
189 	, [loop_cnt_2]"m"(loop_cnt[2]) \
190 	, [loop_cnt_3]"m"(loop_cnt[3]) \
191 	, [loop_cnt_4]"m"(loop_cnt[4]) \
192 	, [loop_cnt_5]"m"(loop_cnt[5]) \
193 	, [loop_cnt_6]"m"(loop_cnt[6])
194 
195 #define INJECT_ASM_REG	"$5"
196 
197 #define RSEQ_INJECT_CLOBBER \
198 	, INJECT_ASM_REG
199 
200 #define RSEQ_INJECT_ASM(n) \
201 	"lw " INJECT_ASM_REG ", %[loop_cnt_" #n "]\n\t" \
202 	"beqz " INJECT_ASM_REG ", 333f\n\t" \
203 	"222:\n\t" \
204 	"addiu " INJECT_ASM_REG ", -1\n\t" \
205 	"bnez " INJECT_ASM_REG ", 222b\n\t" \
206 	"333:\n\t"
207 #elif defined(__riscv)
208 
209 #define RSEQ_INJECT_INPUT \
210 	, [loop_cnt_1]"m"(loop_cnt[1]) \
211 	, [loop_cnt_2]"m"(loop_cnt[2]) \
212 	, [loop_cnt_3]"m"(loop_cnt[3]) \
213 	, [loop_cnt_4]"m"(loop_cnt[4]) \
214 	, [loop_cnt_5]"m"(loop_cnt[5]) \
215 	, [loop_cnt_6]"m"(loop_cnt[6])
216 
217 #define INJECT_ASM_REG	"t1"
218 
219 #define RSEQ_INJECT_CLOBBER \
220 	, INJECT_ASM_REG
221 
222 #define RSEQ_INJECT_ASM(n)					\
223 	"lw " INJECT_ASM_REG ", %[loop_cnt_" #n "]\n\t"		\
224 	"beqz " INJECT_ASM_REG ", 333f\n\t"			\
225 	"222:\n\t"						\
226 	"addi  " INJECT_ASM_REG "," INJECT_ASM_REG ", -1\n\t"	\
227 	"bnez " INJECT_ASM_REG ", 222b\n\t"			\
228 	"333:\n\t"
229 
230 
231 #else
232 #error unsupported target
233 #endif
234 
235 #define RSEQ_INJECT_FAILED \
236 	nr_abort++;
237 
238 #define RSEQ_INJECT_C(n) \
239 { \
240 	int loc_i, loc_nr_loops = loop_cnt[n]; \
241 	\
242 	for (loc_i = 0; loc_i < loc_nr_loops; loc_i++) { \
243 		rseq_barrier(); \
244 	} \
245 	if (loc_nr_loops == -1 && opt_modulo) { \
246 		if (yield_mod_cnt == opt_modulo - 1) { \
247 			if (opt_sleep > 0) \
248 				poll(NULL, 0, opt_sleep); \
249 			if (opt_yield) \
250 				sched_yield(); \
251 			if (opt_signal) \
252 				raise(SIGUSR1); \
253 			yield_mod_cnt = 0; \
254 		} else { \
255 			yield_mod_cnt++; \
256 		} \
257 	} \
258 }
259 
260 #else
261 
262 #define printf_verbose(fmt, ...)
263 
264 #endif /* BENCHMARK */
265 
266 #include "rseq.h"
267 
268 static enum rseq_mo opt_mo = RSEQ_MO_RELAXED;
269 
270 #ifdef RSEQ_ARCH_HAS_OFFSET_DEREF_ADDV
271 #define TEST_MEMBARRIER
272 
273 static int sys_membarrier(int cmd, int flags, int cpu_id)
274 {
275 	return syscall(__NR_membarrier, cmd, flags, cpu_id);
276 }
277 #endif
278 
279 #ifdef BUILDOPT_RSEQ_PERCPU_MM_CID
280 # define RSEQ_PERCPU	RSEQ_PERCPU_MM_CID
281 static
282 int get_current_cpu_id(void)
283 {
284 	return rseq_current_mm_cid();
285 }
286 static
287 bool rseq_validate_cpu_id(void)
288 {
289 	return rseq_mm_cid_available();
290 }
291 static
292 bool rseq_use_cpu_index(void)
293 {
294 	return false;	/* Use mm_cid */
295 }
296 # ifdef TEST_MEMBARRIER
297 /*
298  * Membarrier does not currently support targeting a mm_cid, so
299  * issue the barrier on all cpus.
300  */
301 static
302 int rseq_membarrier_expedited(int cpu)
303 {
304 	return sys_membarrier(MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ,
305 			      0, 0);
306 }
307 # endif /* TEST_MEMBARRIER */
308 #else
309 # define RSEQ_PERCPU	RSEQ_PERCPU_CPU_ID
310 static
311 int get_current_cpu_id(void)
312 {
313 	return rseq_cpu_start();
314 }
315 static
316 bool rseq_validate_cpu_id(void)
317 {
318 	return rseq_current_cpu_raw() >= 0;
319 }
320 static
321 bool rseq_use_cpu_index(void)
322 {
323 	return true;	/* Use cpu_id as index. */
324 }
325 # ifdef TEST_MEMBARRIER
326 static
327 int rseq_membarrier_expedited(int cpu)
328 {
329 	return sys_membarrier(MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ,
330 			      MEMBARRIER_CMD_FLAG_CPU, cpu);
331 }
332 # endif /* TEST_MEMBARRIER */
333 #endif
334 
335 struct percpu_lock_entry {
336 	intptr_t v;
337 } __attribute__((aligned(128)));
338 
339 struct percpu_lock {
340 	struct percpu_lock_entry c[CPU_SETSIZE];
341 };
342 
343 struct test_data_entry {
344 	intptr_t count;
345 } __attribute__((aligned(128)));
346 
347 struct spinlock_test_data {
348 	struct percpu_lock lock;
349 	struct test_data_entry c[CPU_SETSIZE];
350 };
351 
352 struct spinlock_thread_test_data {
353 	struct spinlock_test_data *data;
354 	long long reps;
355 	int reg;
356 };
357 
358 struct inc_test_data {
359 	struct test_data_entry c[CPU_SETSIZE];
360 };
361 
362 struct inc_thread_test_data {
363 	struct inc_test_data *data;
364 	long long reps;
365 	int reg;
366 };
367 
368 struct percpu_list_node {
369 	intptr_t data;
370 	struct percpu_list_node *next;
371 };
372 
373 struct percpu_list_entry {
374 	struct percpu_list_node *head;
375 } __attribute__((aligned(128)));
376 
377 struct percpu_list {
378 	struct percpu_list_entry c[CPU_SETSIZE];
379 };
380 
381 #define BUFFER_ITEM_PER_CPU	100
382 
383 struct percpu_buffer_node {
384 	intptr_t data;
385 };
386 
387 struct percpu_buffer_entry {
388 	intptr_t offset;
389 	intptr_t buflen;
390 	struct percpu_buffer_node **array;
391 } __attribute__((aligned(128)));
392 
393 struct percpu_buffer {
394 	struct percpu_buffer_entry c[CPU_SETSIZE];
395 };
396 
397 #define MEMCPY_BUFFER_ITEM_PER_CPU	100
398 
399 struct percpu_memcpy_buffer_node {
400 	intptr_t data1;
401 	uint64_t data2;
402 };
403 
404 struct percpu_memcpy_buffer_entry {
405 	intptr_t offset;
406 	intptr_t buflen;
407 	struct percpu_memcpy_buffer_node *array;
408 } __attribute__((aligned(128)));
409 
410 struct percpu_memcpy_buffer {
411 	struct percpu_memcpy_buffer_entry c[CPU_SETSIZE];
412 };
413 
414 /* A simple percpu spinlock. Grabs lock on current cpu. */
415 static int rseq_this_cpu_lock(struct percpu_lock *lock)
416 {
417 	int cpu;
418 
419 	for (;;) {
420 		int ret;
421 
422 		cpu = get_current_cpu_id();
423 		if (cpu < 0) {
424 			fprintf(stderr, "pid: %d: tid: %d, cpu: %d: cid: %d\n",
425 					getpid(), (int) rseq_gettid(), rseq_current_cpu_raw(), cpu);
426 			abort();
427 		}
428 		ret = rseq_cmpeqv_storev(RSEQ_MO_RELAXED, RSEQ_PERCPU,
429 					 &lock->c[cpu].v,
430 					 0, 1, cpu);
431 		if (rseq_likely(!ret))
432 			break;
433 		/* Retry if comparison fails or rseq aborts. */
434 	}
435 	/*
436 	 * Acquire semantic when taking lock after control dependency.
437 	 * Matches rseq_smp_store_release().
438 	 */
439 	rseq_smp_acquire__after_ctrl_dep();
440 	return cpu;
441 }
442 
443 static void rseq_percpu_unlock(struct percpu_lock *lock, int cpu)
444 {
445 	assert(lock->c[cpu].v == 1);
446 	/*
447 	 * Release lock, with release semantic. Matches
448 	 * rseq_smp_acquire__after_ctrl_dep().
449 	 */
450 	rseq_smp_store_release(&lock->c[cpu].v, 0);
451 }
452 
453 void *test_percpu_spinlock_thread(void *arg)
454 {
455 	struct spinlock_thread_test_data *thread_data = arg;
456 	struct spinlock_test_data *data = thread_data->data;
457 	long long i, reps;
458 
459 	if (!opt_disable_rseq && thread_data->reg &&
460 	    rseq_register_current_thread())
461 		abort();
462 	reps = thread_data->reps;
463 	for (i = 0; i < reps; i++) {
464 		int cpu = rseq_this_cpu_lock(&data->lock);
465 		data->c[cpu].count++;
466 		rseq_percpu_unlock(&data->lock, cpu);
467 #ifndef BENCHMARK
468 		if (i != 0 && !(i % (reps / 10)))
469 			printf_verbose("tid %d: count %lld\n",
470 				       (int) rseq_gettid(), i);
471 #endif
472 	}
473 	printf_verbose("tid %d: number of rseq abort: %d, signals delivered: %u\n",
474 		       (int) rseq_gettid(), nr_abort, signals_delivered);
475 	if (!opt_disable_rseq && thread_data->reg &&
476 	    rseq_unregister_current_thread())
477 		abort();
478 	return NULL;
479 }
480 
481 /*
482  * A simple test which implements a sharded counter using a per-cpu
483  * lock.  Obviously real applications might prefer to simply use a
484  * per-cpu increment; however, this is reasonable for a test and the
485  * lock can be extended to synchronize more complicated operations.
486  */
487 void test_percpu_spinlock(void)
488 {
489 	const int num_threads = opt_threads;
490 	int i, ret;
491 	uint64_t sum;
492 	pthread_t test_threads[num_threads];
493 	struct spinlock_test_data data;
494 	struct spinlock_thread_test_data thread_data[num_threads];
495 
496 	memset(&data, 0, sizeof(data));
497 	for (i = 0; i < num_threads; i++) {
498 		thread_data[i].reps = opt_reps;
499 		if (opt_disable_mod <= 0 || (i % opt_disable_mod))
500 			thread_data[i].reg = 1;
501 		else
502 			thread_data[i].reg = 0;
503 		thread_data[i].data = &data;
504 		ret = pthread_create(&test_threads[i], NULL,
505 				     test_percpu_spinlock_thread,
506 				     &thread_data[i]);
507 		if (ret) {
508 			errno = ret;
509 			perror("pthread_create");
510 			abort();
511 		}
512 	}
513 
514 	for (i = 0; i < num_threads; i++) {
515 		ret = pthread_join(test_threads[i], NULL);
516 		if (ret) {
517 			errno = ret;
518 			perror("pthread_join");
519 			abort();
520 		}
521 	}
522 
523 	sum = 0;
524 	for (i = 0; i < CPU_SETSIZE; i++)
525 		sum += data.c[i].count;
526 
527 	assert(sum == (uint64_t)opt_reps * num_threads);
528 }
529 
530 void *test_percpu_inc_thread(void *arg)
531 {
532 	struct inc_thread_test_data *thread_data = arg;
533 	struct inc_test_data *data = thread_data->data;
534 	long long i, reps;
535 
536 	if (!opt_disable_rseq && thread_data->reg &&
537 	    rseq_register_current_thread())
538 		abort();
539 	reps = thread_data->reps;
540 	for (i = 0; i < reps; i++) {
541 		int ret;
542 
543 		do {
544 			int cpu;
545 
546 			cpu = get_current_cpu_id();
547 			ret = rseq_addv(RSEQ_MO_RELAXED, RSEQ_PERCPU,
548 					&data->c[cpu].count, 1, cpu);
549 		} while (rseq_unlikely(ret));
550 #ifndef BENCHMARK
551 		if (i != 0 && !(i % (reps / 10)))
552 			printf_verbose("tid %d: count %lld\n",
553 				       (int) rseq_gettid(), i);
554 #endif
555 	}
556 	printf_verbose("tid %d: number of rseq abort: %d, signals delivered: %u\n",
557 		       (int) rseq_gettid(), nr_abort, signals_delivered);
558 	if (!opt_disable_rseq && thread_data->reg &&
559 	    rseq_unregister_current_thread())
560 		abort();
561 	return NULL;
562 }
563 
564 void test_percpu_inc(void)
565 {
566 	const int num_threads = opt_threads;
567 	int i, ret;
568 	uint64_t sum;
569 	pthread_t test_threads[num_threads];
570 	struct inc_test_data data;
571 	struct inc_thread_test_data thread_data[num_threads];
572 
573 	memset(&data, 0, sizeof(data));
574 	for (i = 0; i < num_threads; i++) {
575 		thread_data[i].reps = opt_reps;
576 		if (opt_disable_mod <= 0 || (i % opt_disable_mod))
577 			thread_data[i].reg = 1;
578 		else
579 			thread_data[i].reg = 0;
580 		thread_data[i].data = &data;
581 		ret = pthread_create(&test_threads[i], NULL,
582 				     test_percpu_inc_thread,
583 				     &thread_data[i]);
584 		if (ret) {
585 			errno = ret;
586 			perror("pthread_create");
587 			abort();
588 		}
589 	}
590 
591 	for (i = 0; i < num_threads; i++) {
592 		ret = pthread_join(test_threads[i], NULL);
593 		if (ret) {
594 			errno = ret;
595 			perror("pthread_join");
596 			abort();
597 		}
598 	}
599 
600 	sum = 0;
601 	for (i = 0; i < CPU_SETSIZE; i++)
602 		sum += data.c[i].count;
603 
604 	assert(sum == (uint64_t)opt_reps * num_threads);
605 }
606 
607 void this_cpu_list_push(struct percpu_list *list,
608 			struct percpu_list_node *node,
609 			int *_cpu)
610 {
611 	int cpu;
612 
613 	for (;;) {
614 		intptr_t *targetptr, newval, expect;
615 		int ret;
616 
617 		cpu = get_current_cpu_id();
618 		/* Load list->c[cpu].head with single-copy atomicity. */
619 		expect = (intptr_t)RSEQ_READ_ONCE(list->c[cpu].head);
620 		newval = (intptr_t)node;
621 		targetptr = (intptr_t *)&list->c[cpu].head;
622 		node->next = (struct percpu_list_node *)expect;
623 		ret = rseq_cmpeqv_storev(RSEQ_MO_RELAXED, RSEQ_PERCPU,
624 					 targetptr, expect, newval, cpu);
625 		if (rseq_likely(!ret))
626 			break;
627 		/* Retry if comparison fails or rseq aborts. */
628 	}
629 	if (_cpu)
630 		*_cpu = cpu;
631 }
632 
633 /*
634  * Unlike a traditional lock-less linked list; the availability of a
635  * rseq primitive allows us to implement pop without concerns over
636  * ABA-type races.
637  */
638 struct percpu_list_node *this_cpu_list_pop(struct percpu_list *list,
639 					   int *_cpu)
640 {
641 	struct percpu_list_node *node = NULL;
642 	int cpu;
643 
644 	for (;;) {
645 		struct percpu_list_node *head;
646 		intptr_t *targetptr, expectnot, *load;
647 		long offset;
648 		int ret;
649 
650 		cpu = get_current_cpu_id();
651 		targetptr = (intptr_t *)&list->c[cpu].head;
652 		expectnot = (intptr_t)NULL;
653 		offset = offsetof(struct percpu_list_node, next);
654 		load = (intptr_t *)&head;
655 		ret = rseq_cmpnev_storeoffp_load(RSEQ_MO_RELAXED, RSEQ_PERCPU,
656 						 targetptr, expectnot,
657 						 offset, load, cpu);
658 		if (rseq_likely(!ret)) {
659 			node = head;
660 			break;
661 		}
662 		if (ret > 0)
663 			break;
664 		/* Retry if rseq aborts. */
665 	}
666 	if (_cpu)
667 		*_cpu = cpu;
668 	return node;
669 }
670 
671 /*
672  * __percpu_list_pop is not safe against concurrent accesses. Should
673  * only be used on lists that are not concurrently modified.
674  */
675 struct percpu_list_node *__percpu_list_pop(struct percpu_list *list, int cpu)
676 {
677 	struct percpu_list_node *node;
678 
679 	node = list->c[cpu].head;
680 	if (!node)
681 		return NULL;
682 	list->c[cpu].head = node->next;
683 	return node;
684 }
685 
686 void *test_percpu_list_thread(void *arg)
687 {
688 	long long i, reps;
689 	struct percpu_list *list = (struct percpu_list *)arg;
690 
691 	if (!opt_disable_rseq && rseq_register_current_thread())
692 		abort();
693 
694 	reps = opt_reps;
695 	for (i = 0; i < reps; i++) {
696 		struct percpu_list_node *node;
697 
698 		node = this_cpu_list_pop(list, NULL);
699 		if (opt_yield)
700 			sched_yield();  /* encourage shuffling */
701 		if (node)
702 			this_cpu_list_push(list, node, NULL);
703 	}
704 
705 	printf_verbose("tid %d: number of rseq abort: %d, signals delivered: %u\n",
706 		       (int) rseq_gettid(), nr_abort, signals_delivered);
707 	if (!opt_disable_rseq && rseq_unregister_current_thread())
708 		abort();
709 
710 	return NULL;
711 }
712 
713 /* Simultaneous modification to a per-cpu linked list from many threads.  */
714 void test_percpu_list(void)
715 {
716 	const int num_threads = opt_threads;
717 	int i, j, ret;
718 	uint64_t sum = 0, expected_sum = 0;
719 	struct percpu_list list;
720 	pthread_t test_threads[num_threads];
721 	cpu_set_t allowed_cpus;
722 
723 	memset(&list, 0, sizeof(list));
724 
725 	/* Generate list entries for every usable cpu. */
726 	sched_getaffinity(0, sizeof(allowed_cpus), &allowed_cpus);
727 	for (i = 0; i < CPU_SETSIZE; i++) {
728 		if (rseq_use_cpu_index() && !CPU_ISSET(i, &allowed_cpus))
729 			continue;
730 		for (j = 1; j <= 100; j++) {
731 			struct percpu_list_node *node;
732 
733 			expected_sum += j;
734 
735 			node = malloc(sizeof(*node));
736 			assert(node);
737 			node->data = j;
738 			node->next = list.c[i].head;
739 			list.c[i].head = node;
740 		}
741 	}
742 
743 	for (i = 0; i < num_threads; i++) {
744 		ret = pthread_create(&test_threads[i], NULL,
745 				     test_percpu_list_thread, &list);
746 		if (ret) {
747 			errno = ret;
748 			perror("pthread_create");
749 			abort();
750 		}
751 	}
752 
753 	for (i = 0; i < num_threads; i++) {
754 		ret = pthread_join(test_threads[i], NULL);
755 		if (ret) {
756 			errno = ret;
757 			perror("pthread_join");
758 			abort();
759 		}
760 	}
761 
762 	for (i = 0; i < CPU_SETSIZE; i++) {
763 		struct percpu_list_node *node;
764 
765 		if (rseq_use_cpu_index() && !CPU_ISSET(i, &allowed_cpus))
766 			continue;
767 
768 		while ((node = __percpu_list_pop(&list, i))) {
769 			sum += node->data;
770 			free(node);
771 		}
772 	}
773 
774 	/*
775 	 * All entries should now be accounted for (unless some external
776 	 * actor is interfering with our allowed affinity while this
777 	 * test is running).
778 	 */
779 	assert(sum == expected_sum);
780 }
781 
782 bool this_cpu_buffer_push(struct percpu_buffer *buffer,
783 			  struct percpu_buffer_node *node,
784 			  int *_cpu)
785 {
786 	bool result = false;
787 	int cpu;
788 
789 	for (;;) {
790 		intptr_t *targetptr_spec, newval_spec;
791 		intptr_t *targetptr_final, newval_final;
792 		intptr_t offset;
793 		int ret;
794 
795 		cpu = get_current_cpu_id();
796 		offset = RSEQ_READ_ONCE(buffer->c[cpu].offset);
797 		if (offset == buffer->c[cpu].buflen)
798 			break;
799 		newval_spec = (intptr_t)node;
800 		targetptr_spec = (intptr_t *)&buffer->c[cpu].array[offset];
801 		newval_final = offset + 1;
802 		targetptr_final = &buffer->c[cpu].offset;
803 		ret = rseq_cmpeqv_trystorev_storev(opt_mo, RSEQ_PERCPU,
804 			targetptr_final, offset, targetptr_spec,
805 			newval_spec, newval_final, cpu);
806 		if (rseq_likely(!ret)) {
807 			result = true;
808 			break;
809 		}
810 		/* Retry if comparison fails or rseq aborts. */
811 	}
812 	if (_cpu)
813 		*_cpu = cpu;
814 	return result;
815 }
816 
817 struct percpu_buffer_node *this_cpu_buffer_pop(struct percpu_buffer *buffer,
818 					       int *_cpu)
819 {
820 	struct percpu_buffer_node *head;
821 	int cpu;
822 
823 	for (;;) {
824 		intptr_t *targetptr, newval;
825 		intptr_t offset;
826 		int ret;
827 
828 		cpu = get_current_cpu_id();
829 		/* Load offset with single-copy atomicity. */
830 		offset = RSEQ_READ_ONCE(buffer->c[cpu].offset);
831 		if (offset == 0) {
832 			head = NULL;
833 			break;
834 		}
835 		head = RSEQ_READ_ONCE(buffer->c[cpu].array[offset - 1]);
836 		newval = offset - 1;
837 		targetptr = (intptr_t *)&buffer->c[cpu].offset;
838 		ret = rseq_cmpeqv_cmpeqv_storev(RSEQ_MO_RELAXED, RSEQ_PERCPU,
839 			targetptr, offset,
840 			(intptr_t *)&buffer->c[cpu].array[offset - 1],
841 			(intptr_t)head, newval, cpu);
842 		if (rseq_likely(!ret))
843 			break;
844 		/* Retry if comparison fails or rseq aborts. */
845 	}
846 	if (_cpu)
847 		*_cpu = cpu;
848 	return head;
849 }
850 
851 /*
852  * __percpu_buffer_pop is not safe against concurrent accesses. Should
853  * only be used on buffers that are not concurrently modified.
854  */
855 struct percpu_buffer_node *__percpu_buffer_pop(struct percpu_buffer *buffer,
856 					       int cpu)
857 {
858 	struct percpu_buffer_node *head;
859 	intptr_t offset;
860 
861 	offset = buffer->c[cpu].offset;
862 	if (offset == 0)
863 		return NULL;
864 	head = buffer->c[cpu].array[offset - 1];
865 	buffer->c[cpu].offset = offset - 1;
866 	return head;
867 }
868 
869 void *test_percpu_buffer_thread(void *arg)
870 {
871 	long long i, reps;
872 	struct percpu_buffer *buffer = (struct percpu_buffer *)arg;
873 
874 	if (!opt_disable_rseq && rseq_register_current_thread())
875 		abort();
876 
877 	reps = opt_reps;
878 	for (i = 0; i < reps; i++) {
879 		struct percpu_buffer_node *node;
880 
881 		node = this_cpu_buffer_pop(buffer, NULL);
882 		if (opt_yield)
883 			sched_yield();  /* encourage shuffling */
884 		if (node) {
885 			if (!this_cpu_buffer_push(buffer, node, NULL)) {
886 				/* Should increase buffer size. */
887 				abort();
888 			}
889 		}
890 	}
891 
892 	printf_verbose("tid %d: number of rseq abort: %d, signals delivered: %u\n",
893 		       (int) rseq_gettid(), nr_abort, signals_delivered);
894 	if (!opt_disable_rseq && rseq_unregister_current_thread())
895 		abort();
896 
897 	return NULL;
898 }
899 
900 /* Simultaneous modification to a per-cpu buffer from many threads.  */
901 void test_percpu_buffer(void)
902 {
903 	const int num_threads = opt_threads;
904 	int i, j, ret;
905 	uint64_t sum = 0, expected_sum = 0;
906 	struct percpu_buffer buffer;
907 	pthread_t test_threads[num_threads];
908 	cpu_set_t allowed_cpus;
909 
910 	memset(&buffer, 0, sizeof(buffer));
911 
912 	/* Generate list entries for every usable cpu. */
913 	sched_getaffinity(0, sizeof(allowed_cpus), &allowed_cpus);
914 	for (i = 0; i < CPU_SETSIZE; i++) {
915 		if (rseq_use_cpu_index() && !CPU_ISSET(i, &allowed_cpus))
916 			continue;
917 		/* Worse-case is every item in same CPU. */
918 		buffer.c[i].array =
919 			malloc(sizeof(*buffer.c[i].array) * CPU_SETSIZE *
920 			       BUFFER_ITEM_PER_CPU);
921 		assert(buffer.c[i].array);
922 		buffer.c[i].buflen = CPU_SETSIZE * BUFFER_ITEM_PER_CPU;
923 		for (j = 1; j <= BUFFER_ITEM_PER_CPU; j++) {
924 			struct percpu_buffer_node *node;
925 
926 			expected_sum += j;
927 
928 			/*
929 			 * We could theoretically put the word-sized
930 			 * "data" directly in the buffer. However, we
931 			 * want to model objects that would not fit
932 			 * within a single word, so allocate an object
933 			 * for each node.
934 			 */
935 			node = malloc(sizeof(*node));
936 			assert(node);
937 			node->data = j;
938 			buffer.c[i].array[j - 1] = node;
939 			buffer.c[i].offset++;
940 		}
941 	}
942 
943 	for (i = 0; i < num_threads; i++) {
944 		ret = pthread_create(&test_threads[i], NULL,
945 				     test_percpu_buffer_thread, &buffer);
946 		if (ret) {
947 			errno = ret;
948 			perror("pthread_create");
949 			abort();
950 		}
951 	}
952 
953 	for (i = 0; i < num_threads; i++) {
954 		ret = pthread_join(test_threads[i], NULL);
955 		if (ret) {
956 			errno = ret;
957 			perror("pthread_join");
958 			abort();
959 		}
960 	}
961 
962 	for (i = 0; i < CPU_SETSIZE; i++) {
963 		struct percpu_buffer_node *node;
964 
965 		if (rseq_use_cpu_index() && !CPU_ISSET(i, &allowed_cpus))
966 			continue;
967 
968 		while ((node = __percpu_buffer_pop(&buffer, i))) {
969 			sum += node->data;
970 			free(node);
971 		}
972 		free(buffer.c[i].array);
973 	}
974 
975 	/*
976 	 * All entries should now be accounted for (unless some external
977 	 * actor is interfering with our allowed affinity while this
978 	 * test is running).
979 	 */
980 	assert(sum == expected_sum);
981 }
982 
983 bool this_cpu_memcpy_buffer_push(struct percpu_memcpy_buffer *buffer,
984 				 struct percpu_memcpy_buffer_node item,
985 				 int *_cpu)
986 {
987 	bool result = false;
988 	int cpu;
989 
990 	for (;;) {
991 		intptr_t *targetptr_final, newval_final, offset;
992 		char *destptr, *srcptr;
993 		size_t copylen;
994 		int ret;
995 
996 		cpu = get_current_cpu_id();
997 		/* Load offset with single-copy atomicity. */
998 		offset = RSEQ_READ_ONCE(buffer->c[cpu].offset);
999 		if (offset == buffer->c[cpu].buflen)
1000 			break;
1001 		destptr = (char *)&buffer->c[cpu].array[offset];
1002 		srcptr = (char *)&item;
1003 		/* copylen must be <= 4kB. */
1004 		copylen = sizeof(item);
1005 		newval_final = offset + 1;
1006 		targetptr_final = &buffer->c[cpu].offset;
1007 		ret = rseq_cmpeqv_trymemcpy_storev(
1008 			opt_mo, RSEQ_PERCPU,
1009 			targetptr_final, offset,
1010 			destptr, srcptr, copylen,
1011 			newval_final, cpu);
1012 		if (rseq_likely(!ret)) {
1013 			result = true;
1014 			break;
1015 		}
1016 		/* Retry if comparison fails or rseq aborts. */
1017 	}
1018 	if (_cpu)
1019 		*_cpu = cpu;
1020 	return result;
1021 }
1022 
1023 bool this_cpu_memcpy_buffer_pop(struct percpu_memcpy_buffer *buffer,
1024 				struct percpu_memcpy_buffer_node *item,
1025 				int *_cpu)
1026 {
1027 	bool result = false;
1028 	int cpu;
1029 
1030 	for (;;) {
1031 		intptr_t *targetptr_final, newval_final, offset;
1032 		char *destptr, *srcptr;
1033 		size_t copylen;
1034 		int ret;
1035 
1036 		cpu = get_current_cpu_id();
1037 		/* Load offset with single-copy atomicity. */
1038 		offset = RSEQ_READ_ONCE(buffer->c[cpu].offset);
1039 		if (offset == 0)
1040 			break;
1041 		destptr = (char *)item;
1042 		srcptr = (char *)&buffer->c[cpu].array[offset - 1];
1043 		/* copylen must be <= 4kB. */
1044 		copylen = sizeof(*item);
1045 		newval_final = offset - 1;
1046 		targetptr_final = &buffer->c[cpu].offset;
1047 		ret = rseq_cmpeqv_trymemcpy_storev(RSEQ_MO_RELAXED, RSEQ_PERCPU,
1048 			targetptr_final, offset, destptr, srcptr, copylen,
1049 			newval_final, cpu);
1050 		if (rseq_likely(!ret)) {
1051 			result = true;
1052 			break;
1053 		}
1054 		/* Retry if comparison fails or rseq aborts. */
1055 	}
1056 	if (_cpu)
1057 		*_cpu = cpu;
1058 	return result;
1059 }
1060 
1061 /*
1062  * __percpu_memcpy_buffer_pop is not safe against concurrent accesses. Should
1063  * only be used on buffers that are not concurrently modified.
1064  */
1065 bool __percpu_memcpy_buffer_pop(struct percpu_memcpy_buffer *buffer,
1066 				struct percpu_memcpy_buffer_node *item,
1067 				int cpu)
1068 {
1069 	intptr_t offset;
1070 
1071 	offset = buffer->c[cpu].offset;
1072 	if (offset == 0)
1073 		return false;
1074 	memcpy(item, &buffer->c[cpu].array[offset - 1], sizeof(*item));
1075 	buffer->c[cpu].offset = offset - 1;
1076 	return true;
1077 }
1078 
1079 void *test_percpu_memcpy_buffer_thread(void *arg)
1080 {
1081 	long long i, reps;
1082 	struct percpu_memcpy_buffer *buffer = (struct percpu_memcpy_buffer *)arg;
1083 
1084 	if (!opt_disable_rseq && rseq_register_current_thread())
1085 		abort();
1086 
1087 	reps = opt_reps;
1088 	for (i = 0; i < reps; i++) {
1089 		struct percpu_memcpy_buffer_node item;
1090 		bool result;
1091 
1092 		result = this_cpu_memcpy_buffer_pop(buffer, &item, NULL);
1093 		if (opt_yield)
1094 			sched_yield();  /* encourage shuffling */
1095 		if (result) {
1096 			if (!this_cpu_memcpy_buffer_push(buffer, item, NULL)) {
1097 				/* Should increase buffer size. */
1098 				abort();
1099 			}
1100 		}
1101 	}
1102 
1103 	printf_verbose("tid %d: number of rseq abort: %d, signals delivered: %u\n",
1104 		       (int) rseq_gettid(), nr_abort, signals_delivered);
1105 	if (!opt_disable_rseq && rseq_unregister_current_thread())
1106 		abort();
1107 
1108 	return NULL;
1109 }
1110 
1111 /* Simultaneous modification to a per-cpu buffer from many threads.  */
1112 void test_percpu_memcpy_buffer(void)
1113 {
1114 	const int num_threads = opt_threads;
1115 	int i, j, ret;
1116 	uint64_t sum = 0, expected_sum = 0;
1117 	struct percpu_memcpy_buffer buffer;
1118 	pthread_t test_threads[num_threads];
1119 	cpu_set_t allowed_cpus;
1120 
1121 	memset(&buffer, 0, sizeof(buffer));
1122 
1123 	/* Generate list entries for every usable cpu. */
1124 	sched_getaffinity(0, sizeof(allowed_cpus), &allowed_cpus);
1125 	for (i = 0; i < CPU_SETSIZE; i++) {
1126 		if (rseq_use_cpu_index() && !CPU_ISSET(i, &allowed_cpus))
1127 			continue;
1128 		/* Worse-case is every item in same CPU. */
1129 		buffer.c[i].array =
1130 			malloc(sizeof(*buffer.c[i].array) * CPU_SETSIZE *
1131 			       MEMCPY_BUFFER_ITEM_PER_CPU);
1132 		assert(buffer.c[i].array);
1133 		buffer.c[i].buflen = CPU_SETSIZE * MEMCPY_BUFFER_ITEM_PER_CPU;
1134 		for (j = 1; j <= MEMCPY_BUFFER_ITEM_PER_CPU; j++) {
1135 			expected_sum += 2 * j + 1;
1136 
1137 			/*
1138 			 * We could theoretically put the word-sized
1139 			 * "data" directly in the buffer. However, we
1140 			 * want to model objects that would not fit
1141 			 * within a single word, so allocate an object
1142 			 * for each node.
1143 			 */
1144 			buffer.c[i].array[j - 1].data1 = j;
1145 			buffer.c[i].array[j - 1].data2 = j + 1;
1146 			buffer.c[i].offset++;
1147 		}
1148 	}
1149 
1150 	for (i = 0; i < num_threads; i++) {
1151 		ret = pthread_create(&test_threads[i], NULL,
1152 				     test_percpu_memcpy_buffer_thread,
1153 				     &buffer);
1154 		if (ret) {
1155 			errno = ret;
1156 			perror("pthread_create");
1157 			abort();
1158 		}
1159 	}
1160 
1161 	for (i = 0; i < num_threads; i++) {
1162 		ret = pthread_join(test_threads[i], NULL);
1163 		if (ret) {
1164 			errno = ret;
1165 			perror("pthread_join");
1166 			abort();
1167 		}
1168 	}
1169 
1170 	for (i = 0; i < CPU_SETSIZE; i++) {
1171 		struct percpu_memcpy_buffer_node item;
1172 
1173 		if (rseq_use_cpu_index() && !CPU_ISSET(i, &allowed_cpus))
1174 			continue;
1175 
1176 		while (__percpu_memcpy_buffer_pop(&buffer, &item, i)) {
1177 			sum += item.data1;
1178 			sum += item.data2;
1179 		}
1180 		free(buffer.c[i].array);
1181 	}
1182 
1183 	/*
1184 	 * All entries should now be accounted for (unless some external
1185 	 * actor is interfering with our allowed affinity while this
1186 	 * test is running).
1187 	 */
1188 	assert(sum == expected_sum);
1189 }
1190 
1191 static void test_signal_interrupt_handler(int signo)
1192 {
1193 	signals_delivered++;
1194 }
1195 
1196 static int set_signal_handler(void)
1197 {
1198 	int ret = 0;
1199 	struct sigaction sa;
1200 	sigset_t sigset;
1201 
1202 	ret = sigemptyset(&sigset);
1203 	if (ret < 0) {
1204 		perror("sigemptyset");
1205 		return ret;
1206 	}
1207 
1208 	sa.sa_handler = test_signal_interrupt_handler;
1209 	sa.sa_mask = sigset;
1210 	sa.sa_flags = 0;
1211 	ret = sigaction(SIGUSR1, &sa, NULL);
1212 	if (ret < 0) {
1213 		perror("sigaction");
1214 		return ret;
1215 	}
1216 
1217 	printf_verbose("Signal handler set for SIGUSR1\n");
1218 
1219 	return ret;
1220 }
1221 
1222 /* Test MEMBARRIER_CMD_PRIVATE_RESTART_RSEQ_ON_CPU membarrier command. */
1223 #ifdef TEST_MEMBARRIER
1224 struct test_membarrier_thread_args {
1225 	int stop;
1226 	intptr_t percpu_list_ptr;
1227 };
1228 
1229 /* Worker threads modify data in their "active" percpu lists. */
1230 void *test_membarrier_worker_thread(void *arg)
1231 {
1232 	struct test_membarrier_thread_args *args =
1233 		(struct test_membarrier_thread_args *)arg;
1234 	const int iters = opt_reps;
1235 	int i;
1236 
1237 	if (rseq_register_current_thread()) {
1238 		fprintf(stderr, "Error: rseq_register_current_thread(...) failed(%d): %s\n",
1239 			errno, strerror(errno));
1240 		abort();
1241 	}
1242 
1243 	/* Wait for initialization. */
1244 	while (!__atomic_load_n(&args->percpu_list_ptr, __ATOMIC_ACQUIRE)) {}
1245 
1246 	for (i = 0; i < iters; ++i) {
1247 		int ret;
1248 
1249 		do {
1250 			int cpu = get_current_cpu_id();
1251 
1252 			ret = rseq_offset_deref_addv(RSEQ_MO_RELAXED, RSEQ_PERCPU,
1253 				&args->percpu_list_ptr,
1254 				sizeof(struct percpu_list_entry) * cpu, 1, cpu);
1255 		} while (rseq_unlikely(ret));
1256 	}
1257 
1258 	if (rseq_unregister_current_thread()) {
1259 		fprintf(stderr, "Error: rseq_unregister_current_thread(...) failed(%d): %s\n",
1260 			errno, strerror(errno));
1261 		abort();
1262 	}
1263 	return NULL;
1264 }
1265 
1266 void test_membarrier_init_percpu_list(struct percpu_list *list)
1267 {
1268 	int i;
1269 
1270 	memset(list, 0, sizeof(*list));
1271 	for (i = 0; i < CPU_SETSIZE; i++) {
1272 		struct percpu_list_node *node;
1273 
1274 		node = malloc(sizeof(*node));
1275 		assert(node);
1276 		node->data = 0;
1277 		node->next = NULL;
1278 		list->c[i].head = node;
1279 	}
1280 }
1281 
1282 void test_membarrier_free_percpu_list(struct percpu_list *list)
1283 {
1284 	int i;
1285 
1286 	for (i = 0; i < CPU_SETSIZE; i++)
1287 		free(list->c[i].head);
1288 }
1289 
1290 /*
1291  * The manager thread swaps per-cpu lists that worker threads see,
1292  * and validates that there are no unexpected modifications.
1293  */
1294 void *test_membarrier_manager_thread(void *arg)
1295 {
1296 	struct test_membarrier_thread_args *args =
1297 		(struct test_membarrier_thread_args *)arg;
1298 	struct percpu_list list_a, list_b;
1299 	intptr_t expect_a = 0, expect_b = 0;
1300 	int cpu_a = 0, cpu_b = 0;
1301 
1302 	if (rseq_register_current_thread()) {
1303 		fprintf(stderr, "Error: rseq_register_current_thread(...) failed(%d): %s\n",
1304 			errno, strerror(errno));
1305 		abort();
1306 	}
1307 
1308 	/* Init lists. */
1309 	test_membarrier_init_percpu_list(&list_a);
1310 	test_membarrier_init_percpu_list(&list_b);
1311 
1312 	__atomic_store_n(&args->percpu_list_ptr, (intptr_t)&list_a, __ATOMIC_RELEASE);
1313 
1314 	while (!__atomic_load_n(&args->stop, __ATOMIC_ACQUIRE)) {
1315 		/* list_a is "active". */
1316 		cpu_a = rand() % CPU_SETSIZE;
1317 		/*
1318 		 * As list_b is "inactive", we should never see changes
1319 		 * to list_b.
1320 		 */
1321 		if (expect_b != __atomic_load_n(&list_b.c[cpu_b].head->data, __ATOMIC_ACQUIRE)) {
1322 			fprintf(stderr, "Membarrier test failed\n");
1323 			abort();
1324 		}
1325 
1326 		/* Make list_b "active". */
1327 		__atomic_store_n(&args->percpu_list_ptr, (intptr_t)&list_b, __ATOMIC_RELEASE);
1328 		if (rseq_membarrier_expedited(cpu_a) &&
1329 				errno != ENXIO /* missing CPU */) {
1330 			perror("sys_membarrier");
1331 			abort();
1332 		}
1333 		/*
1334 		 * Cpu A should now only modify list_b, so the values
1335 		 * in list_a should be stable.
1336 		 */
1337 		expect_a = __atomic_load_n(&list_a.c[cpu_a].head->data, __ATOMIC_ACQUIRE);
1338 
1339 		cpu_b = rand() % CPU_SETSIZE;
1340 		/*
1341 		 * As list_a is "inactive", we should never see changes
1342 		 * to list_a.
1343 		 */
1344 		if (expect_a != __atomic_load_n(&list_a.c[cpu_a].head->data, __ATOMIC_ACQUIRE)) {
1345 			fprintf(stderr, "Membarrier test failed\n");
1346 			abort();
1347 		}
1348 
1349 		/* Make list_a "active". */
1350 		__atomic_store_n(&args->percpu_list_ptr, (intptr_t)&list_a, __ATOMIC_RELEASE);
1351 		if (rseq_membarrier_expedited(cpu_b) &&
1352 				errno != ENXIO /* missing CPU*/) {
1353 			perror("sys_membarrier");
1354 			abort();
1355 		}
1356 		/* Remember a value from list_b. */
1357 		expect_b = __atomic_load_n(&list_b.c[cpu_b].head->data, __ATOMIC_ACQUIRE);
1358 	}
1359 
1360 	test_membarrier_free_percpu_list(&list_a);
1361 	test_membarrier_free_percpu_list(&list_b);
1362 
1363 	if (rseq_unregister_current_thread()) {
1364 		fprintf(stderr, "Error: rseq_unregister_current_thread(...) failed(%d): %s\n",
1365 			errno, strerror(errno));
1366 		abort();
1367 	}
1368 	return NULL;
1369 }
1370 
1371 void test_membarrier(void)
1372 {
1373 	const int num_threads = opt_threads;
1374 	struct test_membarrier_thread_args thread_args;
1375 	pthread_t worker_threads[num_threads];
1376 	pthread_t manager_thread;
1377 	int i, ret;
1378 
1379 	if (sys_membarrier(MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_RSEQ, 0, 0)) {
1380 		perror("sys_membarrier");
1381 		abort();
1382 	}
1383 
1384 	thread_args.stop = 0;
1385 	thread_args.percpu_list_ptr = 0;
1386 	ret = pthread_create(&manager_thread, NULL,
1387 			test_membarrier_manager_thread, &thread_args);
1388 	if (ret) {
1389 		errno = ret;
1390 		perror("pthread_create");
1391 		abort();
1392 	}
1393 
1394 	for (i = 0; i < num_threads; i++) {
1395 		ret = pthread_create(&worker_threads[i], NULL,
1396 				test_membarrier_worker_thread, &thread_args);
1397 		if (ret) {
1398 			errno = ret;
1399 			perror("pthread_create");
1400 			abort();
1401 		}
1402 	}
1403 
1404 
1405 	for (i = 0; i < num_threads; i++) {
1406 		ret = pthread_join(worker_threads[i], NULL);
1407 		if (ret) {
1408 			errno = ret;
1409 			perror("pthread_join");
1410 			abort();
1411 		}
1412 	}
1413 
1414 	__atomic_store_n(&thread_args.stop, 1, __ATOMIC_RELEASE);
1415 	ret = pthread_join(manager_thread, NULL);
1416 	if (ret) {
1417 		errno = ret;
1418 		perror("pthread_join");
1419 		abort();
1420 	}
1421 }
1422 #else /* TEST_MEMBARRIER */
1423 void test_membarrier(void)
1424 {
1425 	fprintf(stderr, "rseq_offset_deref_addv is not implemented on this architecture. "
1426 			"Skipping membarrier test.\n");
1427 }
1428 #endif
1429 
1430 static void show_usage(int argc, char **argv)
1431 {
1432 	printf("Usage : %s <OPTIONS>\n",
1433 		argv[0]);
1434 	printf("OPTIONS:\n");
1435 	printf("	[-1 loops] Number of loops for delay injection 1\n");
1436 	printf("	[-2 loops] Number of loops for delay injection 2\n");
1437 	printf("	[-3 loops] Number of loops for delay injection 3\n");
1438 	printf("	[-4 loops] Number of loops for delay injection 4\n");
1439 	printf("	[-5 loops] Number of loops for delay injection 5\n");
1440 	printf("	[-6 loops] Number of loops for delay injection 6\n");
1441 	printf("	[-7 loops] Number of loops for delay injection 7 (-1 to enable -m)\n");
1442 	printf("	[-8 loops] Number of loops for delay injection 8 (-1 to enable -m)\n");
1443 	printf("	[-9 loops] Number of loops for delay injection 9 (-1 to enable -m)\n");
1444 	printf("	[-m N] Yield/sleep/kill every modulo N (default 0: disabled) (>= 0)\n");
1445 	printf("	[-y] Yield\n");
1446 	printf("	[-k] Kill thread with signal\n");
1447 	printf("	[-s S] S: =0: disabled (default), >0: sleep time (ms)\n");
1448 	printf("	[-t N] Number of threads (default 200)\n");
1449 	printf("	[-r N] Number of repetitions per thread (default 5000)\n");
1450 	printf("	[-d] Disable rseq system call (no initialization)\n");
1451 	printf("	[-D M] Disable rseq for each M threads\n");
1452 	printf("	[-T test] Choose test: (s)pinlock, (l)ist, (b)uffer, (m)emcpy, (i)ncrement, membarrie(r)\n");
1453 	printf("	[-M] Push into buffer and memcpy buffer with memory barriers.\n");
1454 	printf("	[-v] Verbose output.\n");
1455 	printf("	[-h] Show this help.\n");
1456 	printf("\n");
1457 }
1458 
1459 int main(int argc, char **argv)
1460 {
1461 	int i;
1462 
1463 	for (i = 1; i < argc; i++) {
1464 		if (argv[i][0] != '-')
1465 			continue;
1466 		switch (argv[i][1]) {
1467 		case '1':
1468 		case '2':
1469 		case '3':
1470 		case '4':
1471 		case '5':
1472 		case '6':
1473 		case '7':
1474 		case '8':
1475 		case '9':
1476 			if (argc < i + 2) {
1477 				show_usage(argc, argv);
1478 				goto error;
1479 			}
1480 			loop_cnt[argv[i][1] - '0'] = atol(argv[i + 1]);
1481 			i++;
1482 			break;
1483 		case 'm':
1484 			if (argc < i + 2) {
1485 				show_usage(argc, argv);
1486 				goto error;
1487 			}
1488 			opt_modulo = atol(argv[i + 1]);
1489 			if (opt_modulo < 0) {
1490 				show_usage(argc, argv);
1491 				goto error;
1492 			}
1493 			i++;
1494 			break;
1495 		case 's':
1496 			if (argc < i + 2) {
1497 				show_usage(argc, argv);
1498 				goto error;
1499 			}
1500 			opt_sleep = atol(argv[i + 1]);
1501 			if (opt_sleep < 0) {
1502 				show_usage(argc, argv);
1503 				goto error;
1504 			}
1505 			i++;
1506 			break;
1507 		case 'y':
1508 			opt_yield = 1;
1509 			break;
1510 		case 'k':
1511 			opt_signal = 1;
1512 			break;
1513 		case 'd':
1514 			opt_disable_rseq = 1;
1515 			break;
1516 		case 'D':
1517 			if (argc < i + 2) {
1518 				show_usage(argc, argv);
1519 				goto error;
1520 			}
1521 			opt_disable_mod = atol(argv[i + 1]);
1522 			if (opt_disable_mod < 0) {
1523 				show_usage(argc, argv);
1524 				goto error;
1525 			}
1526 			i++;
1527 			break;
1528 		case 't':
1529 			if (argc < i + 2) {
1530 				show_usage(argc, argv);
1531 				goto error;
1532 			}
1533 			opt_threads = atol(argv[i + 1]);
1534 			if (opt_threads < 0) {
1535 				show_usage(argc, argv);
1536 				goto error;
1537 			}
1538 			i++;
1539 			break;
1540 		case 'r':
1541 			if (argc < i + 2) {
1542 				show_usage(argc, argv);
1543 				goto error;
1544 			}
1545 			opt_reps = atoll(argv[i + 1]);
1546 			if (opt_reps < 0) {
1547 				show_usage(argc, argv);
1548 				goto error;
1549 			}
1550 			i++;
1551 			break;
1552 		case 'h':
1553 			show_usage(argc, argv);
1554 			goto end;
1555 		case 'T':
1556 			if (argc < i + 2) {
1557 				show_usage(argc, argv);
1558 				goto error;
1559 			}
1560 			opt_test = *argv[i + 1];
1561 			switch (opt_test) {
1562 			case 's':
1563 			case 'l':
1564 			case 'i':
1565 			case 'b':
1566 			case 'm':
1567 			case 'r':
1568 				break;
1569 			default:
1570 				show_usage(argc, argv);
1571 				goto error;
1572 			}
1573 			i++;
1574 			break;
1575 		case 'v':
1576 			verbose = 1;
1577 			break;
1578 		case 'M':
1579 			opt_mo = RSEQ_MO_RELEASE;
1580 			break;
1581 		default:
1582 			show_usage(argc, argv);
1583 			goto error;
1584 		}
1585 	}
1586 
1587 	loop_cnt_1 = loop_cnt[1];
1588 	loop_cnt_2 = loop_cnt[2];
1589 	loop_cnt_3 = loop_cnt[3];
1590 	loop_cnt_4 = loop_cnt[4];
1591 	loop_cnt_5 = loop_cnt[5];
1592 	loop_cnt_6 = loop_cnt[6];
1593 
1594 	if (set_signal_handler())
1595 		goto error;
1596 
1597 	if (!opt_disable_rseq && rseq_register_current_thread())
1598 		goto error;
1599 	if (!opt_disable_rseq && !rseq_validate_cpu_id()) {
1600 		fprintf(stderr, "Error: cpu id getter unavailable\n");
1601 		goto error;
1602 	}
1603 	switch (opt_test) {
1604 	case 's':
1605 		printf_verbose("spinlock\n");
1606 		test_percpu_spinlock();
1607 		break;
1608 	case 'l':
1609 		printf_verbose("linked list\n");
1610 		test_percpu_list();
1611 		break;
1612 	case 'b':
1613 		printf_verbose("buffer\n");
1614 		test_percpu_buffer();
1615 		break;
1616 	case 'm':
1617 		printf_verbose("memcpy buffer\n");
1618 		test_percpu_memcpy_buffer();
1619 		break;
1620 	case 'i':
1621 		printf_verbose("counter increment\n");
1622 		test_percpu_inc();
1623 		break;
1624 	case 'r':
1625 		printf_verbose("membarrier\n");
1626 		test_membarrier();
1627 		break;
1628 	}
1629 	if (!opt_disable_rseq && rseq_unregister_current_thread())
1630 		abort();
1631 end:
1632 	return 0;
1633 
1634 error:
1635 	return -1;
1636 }
1637