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

   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 <signal.h>
  14#include <stdlib.h>
  15#include <string.h>
  16#include <stdio.h>
  17#include "utils.h"
  18#include "flush_utils.h"
  19
  20int entry_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;
  30        int 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                perror("Unable to read powerpc/entry_flush debugfs file");
  44                SKIP_IF(1);
  45        }
  46
  47        if (rfi_flush_orig != 0) {
  48                if (write_debugfs_file("powerpc/rfi_flush", 0) < 0) {
  49                        perror("error writing to powerpc/rfi_flush debugfs file");
  50                        FAIL_IF(1);
  51                }
  52        }
  53
  54        entry_flush = entry_flush_orig;
  55
  56        fd = perf_event_open_counter(PERF_TYPE_RAW, /* L1d miss */ 0x400f0, -1);
  57        FAIL_IF(fd < 0);
  58
  59        p = (char *)memalign(zero_size, CACHELINE_SIZE);
  60
  61        FAIL_IF(perf_event_enable(fd));
  62
  63        // disable L1 prefetching
  64        set_dscr(1);
  65
  66        iter = repetitions;
  67
  68        /*
  69         * We expect to see l1d miss for each cacheline access when entry_flush
  70         * is set. Allow a small variation on this.
  71         */
  72        l1d_misses_expected = iterations * (zero_size / CACHELINE_SIZE - 2);
  73
  74again:
  75        FAIL_IF(perf_event_reset(fd));
  76
  77        syscall_loop(p, iterations, zero_size);
  78
  79        FAIL_IF(read(fd, &v, sizeof(v)) != sizeof(v));
  80
  81        if (entry_flush && v.l1d_misses >= l1d_misses_expected)
  82                passes++;
  83        else if (!entry_flush && v.l1d_misses < (l1d_misses_expected / 2))
  84                passes++;
  85
  86        l1d_misses_total += v.l1d_misses;
  87
  88        while (--iter)
  89                goto again;
  90
  91        if (passes < repetitions) {
  92                printf("FAIL (L1D misses with entry_flush=%d: %llu %c %lu) [%d/%d failures]\n",
  93                       entry_flush, l1d_misses_total, entry_flush ? '<' : '>',
  94                       entry_flush ? repetitions * l1d_misses_expected :
  95                       repetitions * l1d_misses_expected / 2,
  96                       repetitions - passes, repetitions);
  97                rc = 1;
  98        } else {
  99                printf("PASS (L1D misses with entry_flush=%d: %llu %c %lu) [%d/%d pass]\n",
 100                       entry_flush, l1d_misses_total, entry_flush ? '>' : '<',
 101                       entry_flush ? repetitions * l1d_misses_expected :
 102                       repetitions * l1d_misses_expected / 2,
 103                       passes, repetitions);
 104        }
 105
 106        if (entry_flush == entry_flush_orig) {
 107                entry_flush = !entry_flush_orig;
 108                if (write_debugfs_file("powerpc/entry_flush", entry_flush) < 0) {
 109                        perror("error writing to powerpc/entry_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 (write_debugfs_file("powerpc/entry_flush", entry_flush_orig) < 0) {
 129                perror("unable to restore original value of powerpc/entry_flush debugfs file");
 130                return 1;
 131        }
 132
 133        return rc;
 134}
 135
 136int main(int argc, char *argv[])
 137{
 138        return test_harness(entry_flush_test, "entry_flush_test");
 139}
 140