summaryrefslogtreecommitdiff
path: root/tools/testing/selftests/powerpc/math/vsx_preempt.c
blob: d1601bb889d4c09020acc71039c33246edc5b5f4 (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
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright 2015, Cyril Bur, IBM Corp.
 *
 * This test attempts to see if the VSX registers change across preemption.
 * There is no way to be sure preemption happened so this test just
 * uses many threads and a long wait. As such, a successful test
 * doesn't mean much but a failure is bad.
 */

#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <stdlib.h>
#include <pthread.h>

#include "utils.h"

/* Time to wait for workers to get preempted (seconds) */
#define PREEMPT_TIME 20
/*
 * Factor by which to multiply number of online CPUs for total number of
 * worker threads
 */
#define THREAD_FACTOR 8

/*
 * Ensure there is twice the number of non-volatile VMX regs!
 * check_vmx() is going to use the other half as space to put the live
 * registers before calling vsx_memcmp()
 */
__thread vector int varray[24] = {
	{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}
};

int threads_starting;
int running;

extern long preempt_vsx(vector int *varray, int *threads_starting, int *running);

long vsx_memcmp(vector int *a) {
	vector int zero = {0, 0, 0, 0};
	int i;

	FAIL_IF(a != varray);

	for(i = 0; i < 12; i++) {
		if (memcmp(&a[i + 12], &zero, sizeof(vector int)) == 0) {
			fprintf(stderr, "Detected zero from the VSX reg %d\n", i + 12);
			return 2;
		}
	}

	if (memcmp(a, &a[12], 12 * sizeof(vector int))) {
		long *p = (long *)a;
		fprintf(stderr, "VSX mismatch\n");
		for (i = 0; i < 24; i=i+2)
			fprintf(stderr, "%d: 0x%08lx%08lx | 0x%08lx%08lx\n",
					i/2 + i%2 + 20, p[i], p[i + 1], p[i + 24], p[i + 25]);
		return 1;
	}
	return 0;
}

void *preempt_vsx_c(void *p)
{
	int i, j;
	long rc;
	srand(pthread_self());
	for (i = 0; i < 12; i++)
		for (j = 0; j < 4; j++) {
			varray[i][j] = rand();
			/* Don't want zero because it hides kernel problems */
			if (varray[i][j] == 0)
				j--;
		}
	rc = preempt_vsx(varray, &threads_starting, &running);
	if (rc == 2)
		fprintf(stderr, "Caught zeros in VSX compares\n");
	return (void *)rc;
}

int test_preempt_vsx(void)
{
	int i, rc, threads;
	pthread_t *tids;

	SKIP_IF(!have_hwcap(PPC_FEATURE_HAS_VSX));

	threads = sysconf(_SC_NPROCESSORS_ONLN) * THREAD_FACTOR;
	tids = malloc(threads * sizeof(pthread_t));
	FAIL_IF(!tids);

	running = true;
	threads_starting = threads;
	for (i = 0; i < threads; i++) {
		rc = pthread_create(&tids[i], NULL, preempt_vsx_c, NULL);
		FAIL_IF(rc);
	}

	setbuf(stdout, NULL);
	/* Not really nessesary but nice to wait for every thread to start */
	printf("\tWaiting for %d workers to start...", threads_starting);
	while(threads_starting)
		asm volatile("": : :"memory");
	printf("done\n");

	printf("\tWaiting for %d seconds to let some workers get preempted...", PREEMPT_TIME);
	sleep(PREEMPT_TIME);
	printf("done\n");

	printf("\tStopping workers...");
	/*
	 * Working are checking this value every loop. In preempt_vsx 'cmpwi r5,0; bne 2b'.
	 * r5 will have loaded the value of running.
	 */
	running = 0;
	for (i = 0; i < threads; i++) {
		void *rc_p;
		pthread_join(tids[i], &rc_p);

		/*
		 * Harness will say the fail was here, look at why preempt_vsx
		 * returned
		 */
		if ((long) rc_p)
			printf("oops\n");
		FAIL_IF((long) rc_p);
	}
	printf("done\n");

	return 0;
}

int main(int argc, char *argv[])
{
	return test_harness(test_preempt_vsx, "vsx_preempt");
}