tools/testing/selftests/powerpc/mm/prot_sao.c

   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
  18 int 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
  45 int main(void)
  46 {
  47         return test_harness(test_prot_sao, "prot-sao");
  48 }