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

   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 FPU registers are correctly reported in a
  10 * signal context. Each worker just spins checking its FPU registers, at some
  11 * point a signal will interrupt it and C code will check the signal context
  12 * ensuring it is also the same.
  13 */
  14
  15#include <stdio.h>
  16#include <unistd.h>
  17#include <sys/syscall.h>
  18#include <sys/time.h>
  19#include <sys/types.h>
  20#include <sys/wait.h>
  21#include <stdlib.h>
  22#include <pthread.h>
  23
  24#include "utils.h"
  25
  26/* Number of times each thread should receive the signal */
  27#define ITERATIONS 10
  28/*
  29 * Factor by which to multiply number of online CPUs for total number of
  30 * worker threads
  31 */
  32#define THREAD_FACTOR 8
  33
  34__thread double darray[] = {0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0,
  35                     1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0,
  36                     2.1};
  37
  38bool bad_context;
  39int threads_starting;
  40int running;
  41
  42extern long preempt_fpu(double *darray, int *threads_starting, int *running);
  43
  44void signal_fpu_sig(int sig, siginfo_t *info, void *context)
  45{
  46        int i;
  47        ucontext_t *uc = context;
  48        mcontext_t *mc = &uc->uc_mcontext;
  49
  50        /* Only the non volatiles were loaded up */
  51        for (i = 14; i < 32; i++) {
  52                if (mc->fp_regs[i] != darray[i - 14]) {
  53                        bad_context = true;
  54                        break;
  55                }
  56        }
  57}
  58
  59void *signal_fpu_c(void *p)
  60{
  61        int i;
  62        long rc;
  63        struct sigaction act;
  64        act.sa_sigaction = signal_fpu_sig;
  65        act.sa_flags = SA_SIGINFO;
  66        rc = sigaction(SIGUSR1, &act, NULL);
  67        if (rc)
  68                return p;
  69
  70        srand(pthread_self());
  71        for (i = 0; i < 21; i++)
  72                darray[i] = rand();
  73
  74        rc = preempt_fpu(darray, &threads_starting, &running);
  75
  76        return (void *) rc;
  77}
  78
  79int test_signal_fpu(void)
  80{
  81        int i, j, rc, threads;
  82        void *rc_p;
  83        pthread_t *tids;
  84
  85        threads = sysconf(_SC_NPROCESSORS_ONLN) * THREAD_FACTOR;
  86        tids = malloc(threads * sizeof(pthread_t));
  87        FAIL_IF(!tids);
  88
  89        running = true;
  90        threads_starting = threads;
  91        for (i = 0; i < threads; i++) {
  92                rc = pthread_create(&tids[i], NULL, signal_fpu_c, NULL);
  93                FAIL_IF(rc);
  94        }
  95
  96        setbuf(stdout, NULL);
  97        printf("\tWaiting for all workers to start...");
  98        while (threads_starting)
  99                asm volatile("": : :"memory");
 100        printf("done\n");
 101
 102        printf("\tSending signals to all threads %d times...", ITERATIONS);
 103        for (i = 0; i < ITERATIONS; i++) {
 104                for (j = 0; j < threads; j++) {
 105                        pthread_kill(tids[j], SIGUSR1);
 106                }
 107                sleep(1);
 108        }
 109        printf("done\n");
 110
 111        printf("\tStopping workers...");
 112        running = 0;
 113        for (i = 0; i < threads; i++) {
 114                pthread_join(tids[i], &rc_p);
 115
 116                /*
 117                 * Harness will say the fail was here, look at why signal_fpu
 118                 * returned
 119                 */
 120                if ((long) rc_p || bad_context)
 121                        printf("oops\n");
 122                if (bad_context)
 123                        fprintf(stderr, "\t!! bad_context is true\n");
 124                FAIL_IF((long) rc_p || bad_context);
 125        }
 126        printf("done\n");
 127
 128        free(tids);
 129        return 0;
 130}
 131
 132int main(int argc, char *argv[])
 133{
 134        return test_harness(test_signal_fpu, "fpu_signal");
 135}
 136