// SPDX-License-Identifier: GPL-2.0+

/*
 * Copyright 2018 IBM Corporation.
 */

#define __SANE_USERSPACE_TYPES__

#include <sys/types.h>
#include <stdint.h>
#include <malloc.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "utils.h"
#include "flush_utils.h"


int rfi_flush_test(void)
{
        char *p;
        int repetitions = 10;
        int fd, passes = 0, iter, rc = 0;
        struct perf_event_read v;
        __u64 l1d_misses_total = 0;
        unsigned long iterations = 100000, zero_size = 24 * 1024;
        unsigned long l1d_misses_expected;
        int rfi_flush_orig, rfi_flush;
        int have_entry_flush, entry_flush_orig;

        SKIP_IF(geteuid() != 0);

        // The PMU event we use only works on Power7 or later
        SKIP_IF(!have_hwcap(PPC_FEATURE_ARCH_2_06));

        if (read_debugfs_int("powerpc/rfi_flush", &rfi_flush_orig) < 0) {
                perror("Unable to read powerpc/rfi_flush debugfs file");
                SKIP_IF(1);
        }

        if (read_debugfs_int("powerpc/entry_flush", &entry_flush_orig) < 0) {
                have_entry_flush = 0;
        } else {
                have_entry_flush = 1;

                if (entry_flush_orig != 0) {
                        if (write_debugfs_int("powerpc/entry_flush", 0) < 0) {
                                perror("error writing to powerpc/entry_flush debugfs file");
                                return 1;
                        }
                }
        }

        rfi_flush = rfi_flush_orig;

        fd = perf_event_open_counter(PERF_TYPE_HW_CACHE, PERF_L1D_READ_MISS_CONFIG, -1);
        FAIL_IF(fd < 0);

        p = (char *)memalign(zero_size, CACHELINE_SIZE);

        FAIL_IF(perf_event_enable(fd));

        // disable L1 prefetching
        set_dscr(1);

        iter = repetitions;

        /*
         * We expect to see l1d miss for each cacheline access when rfi_flush
         * is set. Allow a small variation on this.
         */
        l1d_misses_expected = iterations * (zero_size / CACHELINE_SIZE - 2);

again:
        FAIL_IF(perf_event_reset(fd));

        syscall_loop(p, iterations, zero_size);

        FAIL_IF(read(fd, &v, sizeof(v)) != sizeof(v));

        if (rfi_flush && v.l1d_misses >= l1d_misses_expected)
                passes++;
        else if (!rfi_flush && v.l1d_misses < (l1d_misses_expected / 2))
                passes++;

        l1d_misses_total += v.l1d_misses;

        while (--iter)
                goto again;

        if (passes < repetitions) {
                printf("FAIL (L1D misses with rfi_flush=%d: %llu %c %lu) [%d/%d failures]\n",
                       rfi_flush, l1d_misses_total, rfi_flush ? '<' : '>',
                       rfi_flush ? repetitions * l1d_misses_expected :
                       repetitions * l1d_misses_expected / 2,
                       repetitions - passes, repetitions);
                rc = 1;
        } else
                printf("PASS (L1D misses with rfi_flush=%d: %llu %c %lu) [%d/%d pass]\n",
                       rfi_flush, l1d_misses_total, rfi_flush ? '>' : '<',
                       rfi_flush ? repetitions * l1d_misses_expected :
                       repetitions * l1d_misses_expected / 2,
                       passes, repetitions);

        if (rfi_flush == rfi_flush_orig) {
                rfi_flush = !rfi_flush_orig;
                if (write_debugfs_int("powerpc/rfi_flush", rfi_flush) < 0) {
                        perror("error writing to powerpc/rfi_flush debugfs file");
                        return 1;
                }
                iter = repetitions;
                l1d_misses_total = 0;
                passes = 0;
                goto again;
        }

        perf_event_disable(fd);
        close(fd);

        set_dscr(0);

        if (write_debugfs_int("powerpc/rfi_flush", rfi_flush_orig) < 0) {
                perror("unable to restore original value of powerpc/rfi_flush debugfs file");
                return 1;
        }

        if (have_entry_flush) {
                if (write_debugfs_int("powerpc/entry_flush", entry_flush_orig) < 0) {
                        perror("unable to restore original value of powerpc/entry_flush "
                               "debugfs file");
                        return 1;
                }
        }

        return rc;
}

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