tools/testing/selftests/powerpc/security/uaccess_flush.c

   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
  21 int 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_int("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_int("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_int("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_int("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_int("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
  88 again:
  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_int("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_int("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_int("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_int("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
 155 int main(int argc, char *argv[])
 156 {
 157         return test_harness(uaccess_flush_test, "uaccess_flush_test");
 158 }