1 /* Definition for thread-local data handling. Generic version. 2 Copyright (C) 2002-2021 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 /* An architecture-specific version of this file has to defined a 20 number of symbols: 21 22 TLS_TCB_AT_TP or TLS_DTV_AT_TP 23 24 The presence of one of these symbols signals which variant of 25 the TLS ABI is used. There are in the moment two variants 26 available: 27 28 * the thread pointer points to a thread control block 29 30 * the thread pointer points to the dynamic thread vector 31 32 33 TLS_TCB_SIZE 34 35 This is the size of the thread control block structure. How 36 this is actually defined depends on the ABI. The thread control 37 block could be internal descriptor of the thread library or 38 just a data structure which allows finding the DTV. 39 40 TLS_INIT_TCB_SIZE 41 42 Similarly, but this value is only used at startup and in the 43 dynamic linker itself. There are no threads in use at that time. 44 45 46 TLS_TCB_ALIGN 47 48 Alignment requirements for the TCB structure. 49 50 TLS_INIT_TCB_ALIGN 51 52 Similarly, but for the structure used at startup time. 53 54 55 INSTALL_DTV(tcb, init_dtv) 56 57 This macro must install the given initial DTV into the thread control 58 block TCB. The normal runtime functionality must then be able to 59 use the value. 60 61 62 TLS_INIT_TP(tcb) 63 64 This macro must initialize the thread pointer to enable normal TLS 65 operation. The parameter is a pointer to the thread control block. 66 ld.so calls this macro once. 67 68 69 THREAD_DTV() 70 71 This macro returns the address of the DTV of the current thread. 72 This normally is done using the thread register which points 73 to the dtv or the TCB (from which the DTV can found). 74 75 76 THREAD_GSCOPE_IN_TCB 77 78 This should be set to 1 if the global scope flag is stored within the TCB. 79 When set to 0, GL(_dl_thread_gscope_count) will be defined to store it. 80 */ 81