1 /* Definition for thread-local data handling. Generic version.
2 Copyright (C) 2002 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
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.
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.
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 <http://www.gnu.org/licenses/>. */
19 /* By default no TLS support is available. This is signaled by the
20 absence of the symbol USE_TLS. */
24 /* An architecture-specific version of this file has to defined a
27 TLS_TCB_AT_TP or TLS_DTV_AT_TP
29 The presence of one of these symbols signals which variant of
30 the TLS ABI is used. There are in the moment two variants
33 * the thread pointer points to a thread control block
35 * the thread pointer points to the dynamic thread vector
40 This is the size of the thread control block structure. How
41 this is actually defined depends on the ABI. The thread control
42 block could be internal descriptor of the thread library or
43 just a data structure which allows finding the DTV.
47 Similarly, but this value is only used at startup and in the
48 dynamic linker itself. There are no threads in use at that time.
53 Alignment requirements for the TCB structure.
57 Similarly, but for the structure used at startup time.
60 INSTALL_DTV(tcb, init_dtv)
62 This macro must install the given initial DTV into the thread control
63 block TCB. The normal runtime functionality must then be able to
67 TLS_INIT_TP(tcb, firstcall)
69 This macro must initialize the thread pointer to enable normal TLS
70 operation. The first parameter is a pointer to the thread control
71 block. The second parameter specifies whether this is the first
72 call for the TCB. ld.so calls this macro more than once.
77 This macro returns the address of the DTV of the current thread.
78 This normally is done using the the thread register which points
79 to the dtv or the TCB (from which the DTV can found).