LXR linux/tools/testing/selftests/powerpc/mm/prot

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Copyright 2016, Michael Ellerman, IBM Corp.
   4 */
   5
   6#include <stdio.h>
   7#include <stdlib.h>
   8#include <string.h>
   9#include <sys/mman.h>
  10#include <unistd.h>
  11
  12#include <asm/cputable.h>
  13
  14#include "utils.h"
  15
  16#define SIZE (64 * 1024)
  17
  18int test_prot_sao(void)
  19{
  20        char *p;
  21
  22        /*
  23         * SAO was introduced in 2.06 and removed in 3.1. It's disabled in
  24         * guests/LPARs by default, so also skip if we are running in a guest.
  25         */
  26        SKIP_IF(!have_hwcap(PPC_FEATURE_ARCH_2_06) ||
  27                have_hwcap2(PPC_FEATURE2_ARCH_3_1) ||
  28                access("/proc/device-tree/rtas/ibm,hypertas-functions", F_OK) == 0);
  29
  30        /*
  31         * Ensure we can ask for PROT_SAO.
  32         * We can't really verify that it does the right thing, but at least we
  33         * confirm the kernel will accept it.
  34         */
  35        p = mmap(NULL, SIZE, PROT_READ | PROT_WRITE | PROT_SAO,
  36                 MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
  37        FAIL_IF(p == MAP_FAILED);
  38
  39        /* Write to the mapping, to at least cause a fault */
  40        memset(p, 0xaa, SIZE);
  41
  42        return 0;
  43}
  44
  45int main(void)
  46{
  47        return test_harness(test_prot_sao, "prot-sao");
  48}
  49