/* Definition for thread-local data handling.  Generic version.

   Copyright (C) 2002-2018 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/>.  */

/* An architecture-specific version of this file has to defined a

   number of symbols:

     TLS_TCB_AT_TP  or  TLS_DTV_AT_TP

     The presence of one of these symbols signals which variant of

     the TLS ABI is used.  There are in the moment two variants

     available:

     * the thread pointer points to a thread control block

     * the thread pointer points to the dynamic thread vector

     TLS_TCB_SIZE

     This is the size of the thread control block structure.  How

     this is actually defined depends on the ABI.  The thread control

     block could be internal descriptor of the thread library or

     just a data structure which allows finding the DTV.

     TLS_INIT_TCB_SIZE

     Similarly, but this value is only used at startup and in the

     dynamic linker itself.  There are no threads in use at that time.

     TLS_TCB_ALIGN

     Alignment requirements for the TCB structure.

     TLS_INIT_TCB_ALIGN

     Similarly, but for the structure used at startup time.

     INSTALL_DTV(tcb, init_dtv)

     This macro must install the given initial DTV into the thread control

     block TCB.  The normal runtime functionality must then be able to

     use the value.

     TLS_INIT_TP(tcb)

     This macro must initialize the thread pointer to enable normal TLS

     operation.  The parameter is a pointer to the thread control block.

     ld.so calls this macro once.

     THREAD_DTV()

     This macro returns the address of the DTV of the current thread.

     This normally is done using the thread register which points

     to the dtv or the TCB (from which the DTV can found).

     THREAD_GSCOPE_IN_TCB

     This should be set to 1 if the global scope flag is stored within the TCB.

     When set to 0, GL(_dl_thread_gscope_count) will be defined to store it.

  */