1 /*
2 * Copyright 2015, Cyril Bur, IBM Corp.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
8 *
9 * This test attempts to see if the VSX registers change across preemption.
10 * There is no way to be sure preemption happened so this test just
11 * uses many threads and a long wait. As such, a successful test
12 * doesn't mean much but a failure is bad.
13 */
14
15 #include <stdio.h>
16 #include <string.h>
17 #include <unistd.h>
18 #include <sys/syscall.h>
19 #include <sys/time.h>
20 #include <sys/types.h>
21 #include <sys/wait.h>
22 #include <stdlib.h>
23 #include <pthread.h>
24
25 #include "utils.h"
26
27 /* Time to wait for workers to get preempted (seconds) */
28 #define PREEMPT_TIME 20
29 /*
30 * Factor by which to multiply number of online CPUs for total number of
31 * worker threads
32 */
33 #define THREAD_FACTOR 8
34
35 /*
36 * Ensure there is twice the number of non-volatile VMX regs!
37 * check_vmx() is going to use the other half as space to put the live
38 * registers before calling vsx_memcmp()
39 */
40 __thread vector int varray[24] = {
41 {1, 2, 3, 4 }, {5, 6, 7, 8 }, {9, 10,11,12},
42 {13,14,15,16}, {17,18,19,20}, {21,22,23,24},
43 {25,26,27,28}, {29,30,31,32}, {33,34,35,36},
44 {37,38,39,40}, {41,42,43,44}, {45,46,47,48}
45 };
46
47 int threads_starting;
48 int running;
49
50 extern long preempt_vsx(vector int *varray, int *threads_starting, int *running);
51
vsx_memcmp(vector int * a)52 long vsx_memcmp(vector int *a) {
53 vector int zero = {0, 0, 0, 0};
54 int i;
55
56 FAIL_IF(a != varray);
57
58 for(i = 0; i < 12; i++) {
59 if (memcmp(&a[i + 12], &zero, sizeof(vector int)) == 0) {
60 fprintf(stderr, "Detected zero from the VSX reg %d\n", i + 12);
61 return 2;
62 }
63 }
64
65 if (memcmp(a, &a[12], 12 * sizeof(vector int))) {
66 long *p = (long *)a;
67 fprintf(stderr, "VSX mismatch\n");
68 for (i = 0; i < 24; i=i+2)
69 fprintf(stderr, "%d: 0x%08lx%08lx | 0x%08lx%08lx\n",
70 i/2 + i%2 + 20, p[i], p[i + 1], p[i + 24], p[i + 25]);
71 return 1;
72 }
73 return 0;
74 }
75
preempt_vsx_c(void * p)76 void *preempt_vsx_c(void *p)
77 {
78 int i, j;
79 long rc;
80 srand(pthread_self());
81 for (i = 0; i < 12; i++)
82 for (j = 0; j < 4; j++) {
83 varray[i][j] = rand();
84 /* Don't want zero because it hides kernel problems */
85 if (varray[i][j] == 0)
86 j--;
87 }
88 rc = preempt_vsx(varray, &threads_starting, &running);
89 if (rc == 2)
90 fprintf(stderr, "Caught zeros in VSX compares\n");
91 return (void *)rc;
92 }
93
test_preempt_vsx(void)94 int test_preempt_vsx(void)
95 {
96 int i, rc, threads;
97 pthread_t *tids;
98
99 threads = sysconf(_SC_NPROCESSORS_ONLN) * THREAD_FACTOR;
100 tids = malloc(threads * sizeof(pthread_t));
101 FAIL_IF(!tids);
102
103 running = true;
104 threads_starting = threads;
105 for (i = 0; i < threads; i++) {
106 rc = pthread_create(&tids[i], NULL, preempt_vsx_c, NULL);
107 FAIL_IF(rc);
108 }
109
110 setbuf(stdout, NULL);
111 /* Not really nessesary but nice to wait for every thread to start */
112 printf("\tWaiting for %d workers to start...", threads_starting);
113 while(threads_starting)
114 asm volatile("": : :"memory");
115 printf("done\n");
116
117 printf("\tWaiting for %d seconds to let some workers get preempted...", PREEMPT_TIME);
118 sleep(PREEMPT_TIME);
119 printf("done\n");
120
121 printf("\tStopping workers...");
122 /*
123 * Working are checking this value every loop. In preempt_vsx 'cmpwi r5,0; bne 2b'.
124 * r5 will have loaded the value of running.
125 */
126 running = 0;
127 for (i = 0; i < threads; i++) {
128 void *rc_p;
129 pthread_join(tids[i], &rc_p);
130
131 /*
132 * Harness will say the fail was here, look at why preempt_vsx
133 * returned
134 */
135 if ((long) rc_p)
136 printf("oops\n");
137 FAIL_IF((long) rc_p);
138 }
139 printf("done\n");
140
141 return 0;
142 }
143
main(int argc,char * argv[])144 int main(int argc, char *argv[])
145 {
146 return test_harness(test_preempt_vsx, "vsx_preempt");
147 }
148