/* Copyright (C) 2017-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library.  If not, see

   <http://www.gnu.org/licenses/>.  */

#include <assert.h>

#include <stdbool.h>

#include <stdlib.h>

#include <unistd.h>

static long int linux_sysconf (int name);

/* Get the value of the system variable NAME.  */

long int

__sysconf (int name)

{

  unsigned ctr;

  /* Unfortunately, the registers that contain the actual cache info

     (CCSIDR_EL1, CLIDR_EL1, and CSSELR_EL1) are protected by the Linux

     kernel (though they need not have been).  However, CTR_EL0 contains

     the *minimum* linesize in the entire cache hierarchy, and is

     accessible to userland, for use in __aarch64_sync_cache_range,

     and it is a reasonable assumption that the L1 cache will have that

     minimum line size.  */

  switch (name)

    {

    case _SC_LEVEL1_ICACHE_LINESIZE:

      asm("mrs\t%0, ctr_el0" : "=r"(ctr));

      return 4 << (ctr & 0xf);

    case _SC_LEVEL1_DCACHE_LINESIZE:

      asm("mrs\t%0, ctr_el0" : "=r"(ctr));

      return 4 << ((ctr >> 16) & 0xf);

    }

  return linux_sysconf (name);

}

/* Now the generic Linux version.  */

#undef __sysconf

#define __sysconf static linux_sysconf

#include <sysdeps/unix/sysv/linux/sysconf.c>