1  /* Test if an executable can read from rtld_global_ro._dl_cache_line_size.
       2     Copyright (C) 2020-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; if not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #include <stdio.h>
      20  #include <stdint.h>
      21  #include <inttypes.h>
      22  #include <sys/auxv.h>
      23  #include <ldsodefs.h>
      24  #include <errno.h>
      25  
      26  /* errnop is required in order to work around BZ #20802.  */
      27  int
      28  test_cache (int *errnop)
      29  {
      30    int cls1 = GLRO (dl_cache_line_size);
      31    errno = *errnop;
      32    uint64_t cls2 = getauxval (AT_DCACHEBSIZE);
      33    *errnop = errno;
      34  
      35    printf ("AT_DCACHEBSIZE      = %" PRIu64 " B\n", cls2);
      36    printf ("_dl_cache_line_size = %d B\n", cls1);
      37  
      38    if (cls1 != cls2)
      39      {
      40        printf ("error: _dl_cache_line_size != AT_DCACHEBSIZE\n");
      41        return 1;
      42      }
      43  
      44    return 0;
      45  }