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}