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 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 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 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 } 143 144 int main(int argc, char *argv[]) 145 { 146 return test_harness(test_preempt_vsx, "vsx_preempt"); 147 } 148
