1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright 2015, Cyril Bur, IBM Corp. 4 * 5 * This test attempts to see if the VSX registers change across preemption. 6 * There is no way to be sure preemption happened so this test just 7 * uses many threads and a long wait. As such, a successful test 8 * doesn't mean much but a failure is bad. 9 */ 10 11 #include <stdio.h> 12 #include <string.h> 13 #include <unistd.h> 14 #include <sys/syscall.h> 15 #include <sys/time.h> 16 #include <sys/types.h> 17 #include <sys/wait.h> 18 #include <stdlib.h> 19 #include <pthread.h> 20 21 #include "utils.h" 22 23 /* Time to wait for workers to get preempted (seconds) */ 24 #define PREEMPT_TIME 20 25 /* 26 * Factor by which to multiply number of online CPUs for total number of 27 * worker threads 28 */ 29 #define THREAD_FACTOR 8 30 31 /* 32 * Ensure there is twice the number of non-volatile VMX regs! 33 * check_vmx() is going to use the other half as space to put the live 34 * registers before calling vsx_memcmp() 35 */ 36 __thread vector int varray[24] = { 37 {1, 2, 3, 4 }, {5, 6, 7, 8 }, {9, 10,11,12}, 38 {13,14,15,16}, {17,18,19,20}, {21,22,23,24}, 39 {25,26,27,28}, {29,30,31,32}, {33,34,35,36}, 40 {37,38,39,40}, {41,42,43,44}, {45,46,47,48} 41 }; 42 43 int threads_starting; 44 int running; 45 46 extern long preempt_vsx(vector int *varray, int *threads_starting, int *running); 47 48 long vsx_memcmp(vector int *a) { 49 vector int zero = {0, 0, 0, 0}; 50 int i; 51 52 FAIL_IF(a != varray); 53 54 for(i = 0; i < 12; i++) { 55 if (memcmp(&a[i + 12], &zero, sizeof(vector int)) == 0) { 56 fprintf(stderr, "Detected zero from the VSX reg %d\n", i + 12); 57 return 2; 58 } 59 } 60 61 if (memcmp(a, &a[12], 12 * sizeof(vector int))) { 62 long *p = (long *)a; 63 fprintf(stderr, "VSX mismatch\n"); 64 for (i = 0; i < 24; i=i+2) 65 fprintf(stderr, "%d: 0x%08lx%08lx | 0x%08lx%08lx\n", 66 i/2 + i%2 + 20, p[i], p[i + 1], p[i + 24], p[i + 25]); 67 return 1; 68 } 69 return 0; 70 } 71 72 void *preempt_vsx_c(void *p) 73 { 74 int i, j; 75 long rc; 76 srand(pthread_self()); 77 for (i = 0; i < 12; i++) 78 for (j = 0; j < 4; j++) { 79 varray[i][j] = rand(); 80 /* Don't want zero because it hides kernel problems */ 81 if (varray[i][j] == 0) 82 j--; 83 } 84 rc = preempt_vsx(varray, &threads_starting, &running); 85 if (rc == 2) 86 fprintf(stderr, "Caught zeros in VSX compares\n"); 87 return (void *)rc; 88 } 89 90 int test_preempt_vsx(void) 91 { 92 int i, rc, threads; 93 pthread_t *tids; 94 95 SKIP_IF(!have_hwcap(PPC_FEATURE_HAS_VSX)); 96 97 threads = sysconf(_SC_NPROCESSORS_ONLN) * THREAD_FACTOR; 98 tids = malloc(threads * sizeof(pthread_t)); 99 FAIL_IF(!tids); 100 101 running = true; 102 threads_starting = threads; 103 for (i = 0; i < threads; i++) { 104 rc = pthread_create(&tids[i], NULL, preempt_vsx_c, NULL); 105 FAIL_IF(rc); 106 } 107 108 setbuf(stdout, NULL); 109 /* Not really nessesary but nice to wait for every thread to start */ 110 printf("\tWaiting for %d workers to start...", threads_starting); 111 while(threads_starting) 112 asm volatile("": : :"memory"); 113 printf("done\n"); 114 115 printf("\tWaiting for %d seconds to let some workers get preempted...", PREEMPT_TIME); 116 sleep(PREEMPT_TIME); 117 printf("done\n"); 118 119 printf("\tStopping workers..."); 120 /* 121 * Working are checking this value every loop. In preempt_vsx 'cmpwi r5,0; bne 2b'. 122 * r5 will have loaded the value of running. 123 */ 124 running = 0; 125 for (i = 0; i < threads; i++) { 126 void *rc_p; 127 pthread_join(tids[i], &rc_p); 128 129 /* 130 * Harness will say the fail was here, look at why preempt_vsx 131 * returned 132 */ 133 if ((long) rc_p) 134 printf("oops\n"); 135 FAIL_IF((long) rc_p); 136 } 137 printf("done\n"); 138 139 return 0; 140 } 141 142 int main(int argc, char *argv[]) 143 { 144 return test_harness(test_preempt_vsx, "vsx_preempt"); 145 } 146