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
  18#define CACHELINE_SIZE 128
  19
  20struct perf_event_read {
  21        __u64 nr;
  22        __u64 l1d_misses;
  23};
  24
  25static inline __u64 load(void *addr)
  26{
  27        __u64 tmp;
  28
  29        asm volatile("ld %0,0(%1)" : "=r"(tmp) : "b"(addr));
  30
  31        return tmp;
  32}
  33
  34static void syscall_loop(char *p, unsigned long iterations,
  35                         unsigned long zero_size)
  36{
  37        for (unsigned long i = 0; i < iterations; i++) {
  38                for (unsigned long j = 0; j < zero_size; j += CACHELINE_SIZE)
  39                        load(p + j);
  40                getppid();
  41        }
  42}
  43
  44int rfi_flush_test(void)
  45{
  46        char *p;
  47        int repetitions = 10;
  48        int fd, passes = 0, iter, rc = 0;
  49        struct perf_event_read v;
  50        __u64 l1d_misses_total = 0;
  51        unsigned long iterations = 100000, zero_size = 24 * 1024;
  52        unsigned long l1d_misses_expected;
  53        int rfi_flush_org, rfi_flush;
  54
  55        SKIP_IF(geteuid() != 0);
  56
  57        if (read_debugfs_file("powerpc/rfi_flush", &rfi_flush_org)) {
  58                perror("Unable to read powerpc/rfi_flush debugfs file");
  59                SKIP_IF(1);
  60        }
  61
  62        rfi_flush = rfi_flush_org;
  63
  64        fd = perf_event_open_counter(PERF_TYPE_RAW, /* L1d miss */ 0x400f0, -1);
  65        FAIL_IF(fd < 0);
  66
  67        p = (char *)memalign(zero_size, CACHELINE_SIZE);
  68
  69        FAIL_IF(perf_event_enable(fd));
  70
  71        set_dscr(1);
  72
  73        iter = repetitions;
  74
  75        /*
  76         * We expect to see l1d miss for each cacheline access when rfi_flush
  77         * is set. Allow a small variation on this.
  78         */
  79        l1d_misses_expected = iterations * (zero_size / CACHELINE_SIZE - 2);
  80
  81again:
  82        FAIL_IF(perf_event_reset(fd));
  83
  84        syscall_loop(p, iterations, zero_size);
  85
  86        FAIL_IF(read(fd, &v, sizeof(v)) != sizeof(v));
  87
  88        if (rfi_flush && v.l1d_misses >= l1d_misses_expected)
  89                passes++;
  90        else if (!rfi_flush && v.l1d_misses < (l1d_misses_expected / 2))
  91                passes++;
  92
  93        l1d_misses_total += v.l1d_misses;
  94
  95        while (--iter)
  96                goto again;
  97
  98        if (passes < repetitions) {
  99                printf("FAIL (L1D misses with rfi_flush=%d: %llu %c %lu) [%d/%d failures]\n",
 100                       rfi_flush, l1d_misses_total, rfi_flush ? '<' : '>',
 101                       rfi_flush ? repetitions * l1d_misses_expected :
 102                       repetitions * l1d_misses_expected / 2,
 103                       repetitions - passes, repetitions);
 104                rc = 1;
 105        } else
 106                printf("PASS (L1D misses with rfi_flush=%d: %llu %c %lu) [%d/%d pass]\n",
 107                       rfi_flush, l1d_misses_total, rfi_flush ? '>' : '<',
 108                       rfi_flush ? repetitions * l1d_misses_expected :
 109                       repetitions * l1d_misses_expected / 2,
 110                       passes, repetitions);
 111
 112        if (rfi_flush == rfi_flush_org) {
 113                rfi_flush = !rfi_flush_org;
 114                if (write_debugfs_file("powerpc/rfi_flush", rfi_flush) < 0) {
 115                        perror("error writing to powerpc/rfi_flush debugfs file");
 116                        return 1;
 117                }
 118                iter = repetitions;
 119                l1d_misses_total = 0;
 120                passes = 0;
 121                goto again;
 122        }
 123
 124        perf_event_disable(fd);
 125        close(fd);
 126
 127        set_dscr(0);
 128
 129        if (write_debugfs_file("powerpc/rfi_flush", rfi_flush_org) < 0) {
 130                perror("unable to restore original value of powerpc/rfi_flush debugfs file");
 131                return 1;
 132        }
 133
 134        return rc;
 135}
 136
 137int main(int argc, char *argv[])
 138{
 139        return test_harness(rfi_flush_test, "rfi_flush_test");
 140}
 141