root/tools/testing/selftests/powerpc/math/fpu_signal.c

DEFINITIONS

1. signal_fpu_sig
2. signal_fpu_c
3. test_signal_fpu
4. main

   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 FPU registers are correctly reported in a
   6  * signal context. Each worker just spins checking its FPU registers, at some
   7  * point a signal will interrupt it and C code will check the signal context
   8  * ensuring it is also the same.
   9  */
  10 
  11 #include <stdio.h>
  12 #include <unistd.h>
  13 #include <sys/syscall.h>
  14 #include <sys/time.h>
  15 #include <sys/types.h>
  16 #include <sys/wait.h>
  17 #include <stdlib.h>
  18 #include <pthread.h>
  19 
  20 #include "utils.h"
  21 
  22 /* Number of times each thread should receive the signal */
  23 #define ITERATIONS 10
  24 /*
  25  * Factor by which to multiply number of online CPUs for total number of
  26  * worker threads
  27  */
  28 #define THREAD_FACTOR 8
  29 
  30 __thread double darray[] = {0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0,
  31                      1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0,
  32                      2.1};
  33 
  34 bool bad_context;
  35 int threads_starting;
  36 int running;
  37 
  38 extern long preempt_fpu(double *darray, int *threads_starting, int *running);
  39 
  40 void signal_fpu_sig(int sig, siginfo_t *info, void *context)
  41 {
  42         int i;
  43         ucontext_t *uc = context;
  44         mcontext_t *mc = &uc->uc_mcontext;
  45 
  46         /* Only the non volatiles were loaded up */
  47         for (i = 14; i < 32; i++) {
  48                 if (mc->fp_regs[i] != darray[i - 14]) {
  49                         bad_context = true;
  50                         break;
  51                 }
  52         }
  53 }
  54 
  55 void *signal_fpu_c(void *p)
  56 {
  57         int i;
  58         long rc;
  59         struct sigaction act;
  60         act.sa_sigaction = signal_fpu_sig;
  61         act.sa_flags = SA_SIGINFO;
  62         rc = sigaction(SIGUSR1, &act, NULL);
  63         if (rc)
  64                 return p;
  65 
  66         srand(pthread_self());
  67         for (i = 0; i < 21; i++)
  68                 darray[i] = rand();
  69 
  70         rc = preempt_fpu(darray, &threads_starting, &running);
  71 
  72         return (void *) rc;
  73 }
  74 
  75 int test_signal_fpu(void)
  76 {
  77         int i, j, rc, threads;
  78         void *rc_p;
  79         pthread_t *tids;
  80 
  81         threads = sysconf(_SC_NPROCESSORS_ONLN) * THREAD_FACTOR;
  82         tids = malloc(threads * sizeof(pthread_t));
  83         FAIL_IF(!tids);
  84 
  85         running = true;
  86         threads_starting = threads;
  87         for (i = 0; i < threads; i++) {
  88                 rc = pthread_create(&tids[i], NULL, signal_fpu_c, NULL);
  89                 FAIL_IF(rc);
  90         }
  91 
  92         setbuf(stdout, NULL);
  93         printf("\tWaiting for all workers to start...");
  94         while (threads_starting)
  95                 asm volatile("": : :"memory");
  96         printf("done\n");
  97 
  98         printf("\tSending signals to all threads %d times...", ITERATIONS);
  99         for (i = 0; i < ITERATIONS; i++) {
 100                 for (j = 0; j < threads; j++) {
 101                         pthread_kill(tids[j], SIGUSR1);
 102                 }
 103                 sleep(1);
 104         }
 105         printf("done\n");
 106 
 107         printf("\tStopping workers...");
 108         running = 0;
 109         for (i = 0; i < threads; i++) {
 110                 pthread_join(tids[i], &rc_p);
 111 
 112                 /*
 113                  * Harness will say the fail was here, look at why signal_fpu
 114                  * returned
 115                  */
 116                 if ((long) rc_p || bad_context)
 117                         printf("oops\n");
 118                 if (bad_context)
 119                         fprintf(stderr, "\t!! bad_context is true\n");
 120                 FAIL_IF((long) rc_p || bad_context);
 121         }
 122         printf("done\n");
 123 
 124         free(tids);
 125         return 0;
 126 }
 127 
 128 int main(int argc, char *argv[])
 129 {
 130         return test_harness(test_signal_fpu, "fpu_signal");
 131 }