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

   1// SPDX-License-Identifier: GPL-2.0+
   2
   3/*
   4 * Copyright 2018 IBM Corporation.
   5 * Copyright 2020 Canonical Ltd.
   6 */
   7
   8#define __SANE_USERSPACE_TYPES__
   9
  10#include <sys/types.h>
  11#include <stdint.h>
  12#include <malloc.h>
  13#include <unistd.h>
  14#include <signal.h>
  15#include <stdlib.h>
  16#include <string.h>
  17#include <stdio.h>
  18#include "utils.h"
  19#include "flush_utils.h"
  20
  21int uaccess_flush_test(void)
  22{
  23        char *p;
  24        int repetitions = 10;
  25        int fd, passes = 0, iter, rc = 0;
  26        struct perf_event_read v;
  27        __u64 l1d_misses_total = 0;
  28        unsigned long iterations = 100000, zero_size = 24 * 1024;
  29        unsigned long l1d_misses_expected;
  30        int rfi_flush_orig;
  31        int entry_flush_orig;
  32        int uaccess_flush, uaccess_flush_orig;
  33
  34        SKIP_IF(geteuid() != 0);
  35
  36        // The PMU event we use only works on Power7 or later
  37        SKIP_IF(!have_hwcap(PPC_FEATURE_ARCH_2_06));
  38
  39        if (read_debugfs_file("powerpc/rfi_flush", &rfi_flush_orig) < 0) {
  40                perror("Unable to read powerpc/rfi_flush debugfs file");
  41                SKIP_IF(1);
  42        }
  43
  44        if (read_debugfs_file("powerpc/entry_flush", &entry_flush_orig) < 0) {
  45                perror("Unable to read powerpc/entry_flush debugfs file");
  46                SKIP_IF(1);
  47        }
  48
  49        if (read_debugfs_file("powerpc/uaccess_flush", &uaccess_flush_orig) < 0) {
  50                perror("Unable to read powerpc/entry_flush debugfs file");
  51                SKIP_IF(1);
  52        }
  53
  54        if (rfi_flush_orig != 0) {
  55                if (write_debugfs_file("powerpc/rfi_flush", 0) < 0) {
  56                        perror("error writing to powerpc/rfi_flush debugfs file");
  57                        FAIL_IF(1);
  58                }
  59        }
  60
  61        if (entry_flush_orig != 0) {
  62                if (write_debugfs_file("powerpc/entry_flush", 0) < 0) {
  63                        perror("error writing to powerpc/entry_flush debugfs file");
  64                        FAIL_IF(1);
  65                }
  66        }
  67
  68        uaccess_flush = uaccess_flush_orig;
  69
  70        fd = perf_event_open_counter(PERF_TYPE_HW_CACHE, PERF_L1D_READ_MISS_CONFIG, -1);
  71        FAIL_IF(fd < 0);
  72
  73        p = (char *)memalign(zero_size, CACHELINE_SIZE);
  74
  75        FAIL_IF(perf_event_enable(fd));
  76
  77        // disable L1 prefetching
  78        set_dscr(1);
  79
  80        iter = repetitions;
  81
  82        /*
  83         * We expect to see l1d miss for each cacheline access when entry_flush
  84         * is set. Allow a small variation on this.
  85         */
  86        l1d_misses_expected = iterations * (zero_size / CACHELINE_SIZE - 2);
  87
  88again:
  89        FAIL_IF(perf_event_reset(fd));
  90
  91        syscall_loop_uaccess(p, iterations, zero_size);
  92
  93        FAIL_IF(read(fd, &v, sizeof(v)) != sizeof(v));
  94
  95        if (uaccess_flush && v.l1d_misses >= l1d_misses_expected)
  96                passes++;
  97        else if (!uaccess_flush && v.l1d_misses < (l1d_misses_expected / 2))
  98                passes++;
  99
 100        l1d_misses_total += v.l1d_misses;
 101
 102        while (--iter)
 103                goto again;
 104
 105        if (passes < repetitions) {
 106                printf("FAIL (L1D misses with uaccess_flush=%d: %llu %c %lu) [%d/%d failures]\n",
 107                       uaccess_flush, l1d_misses_total, uaccess_flush ? '<' : '>',
 108                       uaccess_flush ? repetitions * l1d_misses_expected :
 109                       repetitions * l1d_misses_expected / 2,
 110                       repetitions - passes, repetitions);
 111                rc = 1;
 112        } else {
 113                printf("PASS (L1D misses with uaccess_flush=%d: %llu %c %lu) [%d/%d pass]\n",
 114                       uaccess_flush, l1d_misses_total, uaccess_flush ? '>' : '<',
 115                       uaccess_flush ? repetitions * l1d_misses_expected :
 116                       repetitions * l1d_misses_expected / 2,
 117                       passes, repetitions);
 118        }
 119
 120        if (uaccess_flush == uaccess_flush_orig) {
 121                uaccess_flush = !uaccess_flush_orig;
 122                if (write_debugfs_file("powerpc/uaccess_flush", uaccess_flush) < 0) {
 123                        perror("error writing to powerpc/uaccess_flush debugfs file");
 124                        return 1;
 125                }
 126                iter = repetitions;
 127                l1d_misses_total = 0;
 128                passes = 0;
 129                goto again;
 130        }
 131
 132        perf_event_disable(fd);
 133        close(fd);
 134
 135        set_dscr(0);
 136
 137        if (write_debugfs_file("powerpc/rfi_flush", rfi_flush_orig) < 0) {
 138                perror("unable to restore original value of powerpc/rfi_flush debugfs file");
 139                return 1;
 140        }
 141
 142        if (write_debugfs_file("powerpc/entry_flush", entry_flush_orig) < 0) {
 143                perror("unable to restore original value of powerpc/entry_flush debugfs file");
 144                return 1;
 145        }
 146
 147        if (write_debugfs_file("powerpc/uaccess_flush", uaccess_flush_orig) < 0) {
 148                perror("unable to restore original value of powerpc/uaccess_flush debugfs file");
 149                return 1;
 150        }
 151
 152        return rc;
 153}
 154
 155int main(int argc, char *argv[])
 156{
 157        return test_harness(uaccess_flush_test, "uaccess_flush_test");
 158}
 159