// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright 2015, Cyril Bur, IBM Corp.
 *
 * This test attempts to see if the VSX registers change across preemption.
 * There is no way to be sure preemption happened so this test just
 * uses many threads and a long wait. As such, a successful test
 * doesn't mean much but a failure is bad.
 */

#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <stdlib.h>
#include <pthread.h>

#include "utils.h"

/* Time to wait for workers to get preempted (seconds) */
#define PREEMPT_TIME 20
/*
 * Factor by which to multiply number of online CPUs for total number of
 * worker threads
 */
#define THREAD_FACTOR 8

/*
 * Ensure there is twice the number of non-volatile VMX regs!
 * check_vmx() is going to use the other half as space to put the live
 * registers before calling vsx_memcmp()
 */
__thread vector int varray[24] = {
        {1, 2, 3, 4 }, {5, 6, 7, 8 }, {9, 10,11,12},
        {13,14,15,16}, {17,18,19,20}, {21,22,23,24},
        {25,26,27,28}, {29,30,31,32}, {33,34,35,36},
        {37,38,39,40}, {41,42,43,44}, {45,46,47,48}
};

int threads_starting;
int running;

extern long preempt_vsx(vector int *varray, int *threads_starting, int *running);

long vsx_memcmp(vector int *a) {
        vector int zero = {0, 0, 0, 0};
        int i;

        FAIL_IF(a != varray);

        for(i = 0; i < 12; i++) {
                if (memcmp(&a[i + 12], &zero, sizeof(vector int)) == 0) {
                        fprintf(stderr, "Detected zero from the VSX reg %d\n", i + 12);
                        return 2;
                }
        }

        if (memcmp(a, &a[12], 12 * sizeof(vector int))) {
                long *p = (long *)a;
                fprintf(stderr, "VSX mismatch\n");
                for (i = 0; i < 24; i=i+2)
                        fprintf(stderr, "%d: 0x%08lx%08lx | 0x%08lx%08lx\n",
                                        i/2 + i%2 + 20, p[i], p[i + 1], p[i + 24], p[i + 25]);
                return 1;
        }
        return 0;
}

void *preempt_vsx_c(void *p)
{
        int i, j;
        long rc;
        srand(pthread_self());
        for (i = 0; i < 12; i++)
                for (j = 0; j < 4; j++) {
                        varray[i][j] = rand();
                        /* Don't want zero because it hides kernel problems */
                        if (varray[i][j] == 0)
                                j--;
                }
        rc = preempt_vsx(varray, &threads_starting, &running);
        if (rc == 2)
                fprintf(stderr, "Caught zeros in VSX compares\n");
        return (void *)rc;
}

int test_preempt_vsx(void)
{
        int i, rc, threads;
        pthread_t *tids;

        SKIP_IF(!have_hwcap(PPC_FEATURE_HAS_VSX));

        threads = sysconf(_SC_NPROCESSORS_ONLN) * THREAD_FACTOR;
        tids = malloc(threads * sizeof(pthread_t));
        FAIL_IF(!tids);

        running = true;
        threads_starting = threads;
        for (i = 0; i < threads; i++) {
                rc = pthread_create(&tids[i], NULL, preempt_vsx_c, NULL);
                FAIL_IF(rc);
        }

        setbuf(stdout, NULL);
        /* Not really nessesary but nice to wait for every thread to start */
        printf("\tWaiting for %d workers to start...", threads_starting);
        while(threads_starting)
                asm volatile("": : :"memory");
        printf("done\n");

        printf("\tWaiting for %d seconds to let some workers get preempted...", PREEMPT_TIME);
        sleep(PREEMPT_TIME);
        printf("done\n");

        printf("\tStopping workers...");
        /*
         * Working are checking this value every loop. In preempt_vsx 'cmpwi r5,0; bne 2b'.
         * r5 will have loaded the value of running.
         */
        running = 0;
        for (i = 0; i < threads; i++) {
                void *rc_p;
                pthread_join(tids[i], &rc_p);

                /*
                 * Harness will say the fail was here, look at why preempt_vsx
                 * returned
                 */
                if ((long) rc_p)
                        printf("oops\n");
                FAIL_IF((long) rc_p);
        }
        printf("done\n");

        return 0;
}

int main(int argc, char *argv[])
{
        return test_harness(test_preempt_vsx, "vsx_preempt");
}