LXR linux/tools/testing/selftests/powerpc/security/rfi

   1// SPDX-License-Identifier: GPL-2.0+
   2
   3/*
   4 * Copyright 2018 IBM Corporation.
   5 */
   6
   7#define __SANE_USERSPACE_TYPES__
   8
   9#include <sys/types.h>
  10#include <stdint.h>
  11#include <malloc.h>
  12#include <unistd.h>
  13#include <stdlib.h>
  14#include <string.h>
  15#include <stdio.h>
  16#include "utils.h"
  17#include "flush_utils.h"
  18
  19
  20int rfi_flush_test(void)
  21{
  22        char *p;
  23        int repetitions = 10;
  24        int fd, passes = 0, iter, rc = 0;
  25        struct perf_event_read v;
  26        __u64 l1d_misses_total = 0;
  27        unsigned long iterations = 100000, zero_size = 24 * 1024;
  28        unsigned long l1d_misses_expected;
  29        int rfi_flush_orig, rfi_flush;
  30        int have_entry_flush, entry_flush_orig;
  31
  32        SKIP_IF(geteuid() != 0);
  33
  34        // The PMU event we use only works on Power7 or later
  35        SKIP_IF(!have_hwcap(PPC_FEATURE_ARCH_2_06));
  36
  37        if (read_debugfs_file("powerpc/rfi_flush", &rfi_flush_orig) < 0) {
  38                perror("Unable to read powerpc/rfi_flush debugfs file");
  39                SKIP_IF(1);
  40        }
  41
  42        if (read_debugfs_file("powerpc/entry_flush", &entry_flush_orig) < 0) {
  43                have_entry_flush = 0;
  44        } else {
  45                have_entry_flush = 1;
  46
  47                if (entry_flush_orig != 0) {
  48                        if (write_debugfs_file("powerpc/entry_flush", 0) < 0) {
  49                                perror("error writing to powerpc/entry_flush debugfs file");
  50                                return 1;
  51                        }
  52                }
  53        }
  54
  55        rfi_flush = rfi_flush_orig;
  56
  57        fd = perf_event_open_counter(PERF_TYPE_HW_CACHE, PERF_L1D_READ_MISS_CONFIG, -1);
  58        FAIL_IF(fd < 0);
  59
  60        p = (char *)memalign(zero_size, CACHELINE_SIZE);
  61
  62        FAIL_IF(perf_event_enable(fd));
  63
  64        // disable L1 prefetching
  65        set_dscr(1);
  66
  67        iter = repetitions;
  68
  69        /*
  70         * We expect to see l1d miss for each cacheline access when rfi_flush
  71         * is set. Allow a small variation on this.
  72         */
  73        l1d_misses_expected = iterations * (zero_size / CACHELINE_SIZE - 2);
  74
  75again:
  76        FAIL_IF(perf_event_reset(fd));
  77
  78        syscall_loop(p, iterations, zero_size);
  79
  80        FAIL_IF(read(fd, &v, sizeof(v)) != sizeof(v));
  81
  82        if (rfi_flush && v.l1d_misses >= l1d_misses_expected)
  83                passes++;
  84        else if (!rfi_flush && v.l1d_misses < (l1d_misses_expected / 2))
  85                passes++;
  86
  87        l1d_misses_total += v.l1d_misses;
  88
  89        while (--iter)
  90                goto again;
  91
  92        if (passes < repetitions) {
  93                printf("FAIL (L1D misses with rfi_flush=%d: %llu %c %lu) [%d/%d failures]\n",
  94                       rfi_flush, l1d_misses_total, rfi_flush ? '<' : '>',
  95                       rfi_flush ? repetitions * l1d_misses_expected :
  96                       repetitions * l1d_misses_expected / 2,
  97                       repetitions - passes, repetitions);
  98                rc = 1;
  99        } else
 100                printf("PASS (L1D misses with rfi_flush=%d: %llu %c %lu) [%d/%d pass]\n",
 101                       rfi_flush, l1d_misses_total, rfi_flush ? '>' : '<',
 102                       rfi_flush ? repetitions * l1d_misses_expected :
 103                       repetitions * l1d_misses_expected / 2,
 104                       passes, repetitions);
 105
 106        if (rfi_flush == rfi_flush_orig) {
 107                rfi_flush = !rfi_flush_orig;
 108                if (write_debugfs_file("powerpc/rfi_flush", rfi_flush) < 0) {
 109                        perror("error writing to powerpc/rfi_flush debugfs file");
 110                        return 1;
 111                }
 112                iter = repetitions;
 113                l1d_misses_total = 0;
 114                passes = 0;
 115                goto again;
 116        }
 117
 118        perf_event_disable(fd);
 119        close(fd);
 120
 121        set_dscr(0);
 122
 123        if (write_debugfs_file("powerpc/rfi_flush", rfi_flush_orig) < 0) {
 124                perror("unable to restore original value of powerpc/rfi_flush debugfs file");
 125                return 1;
 126        }
 127
 128        if (have_entry_flush) {
 129                if (write_debugfs_file("powerpc/entry_flush", entry_flush_orig) < 0) {
 130                        perror("unable to restore original value of powerpc/entry_flush "
 131                               "debugfs file");
 132                        return 1;
 133                }
 134        }
 135
 136        return rc;
 137}
 138
 139int main(int argc, char *argv[])
 140{
 141        return test_harness(rfi_flush_test, "rfi_flush_test");
 142}
 143