LXR linux/tools/testing/selftests/powerpc/math/fpu

   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
  34bool bad_context;
  35int threads_starting;
  36int running;
  37
  38extern long preempt_fpu(double *darray, int *threads_starting, int *running);
  39
  40void 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
  55void *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
  75int 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
 128int main(int argc, char *argv[])
 129{
 130        return test_harness(test_signal_fpu, "fpu_signal");
 131}
 132