1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2004 Doug Rabson 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 * 28 * $FreeBSD$ 29 */ 30 31 /* 32 * Semi-public interface from thread libraries to rtld for managing 33 * TLS. 34 */ 35 36 #ifndef _RTLD_TLS_H_ 37 #define _RTLD_TLS_H_ 38 39 /* 40 * Allocate a TLS block for a new thread. The memory allocated will 41 * include 'tcbsize' bytes aligned to a 'tcbalign' boundary (in bytes) 42 * for the thread library's private purposes. The location of the TCB 43 * block is returned by this function. For architectures using 44 * 'Variant I' TLS, the thread local storage follows the TCB, and for 45 * 'Variant II', the thread local storage precedes it. For 46 * architectures using the 'Variant II' model (e.g. i386, amd64) the 47 * TCB must begin with two pointer fields which are used by rtld for 48 * its TLS implementation. For the 'Variant I' model, the TCB must 49 * begin with a single pointer field for rtld's implementation. 50 * 51 * If the value of 'oldtls' is non-NULL, the new TLS block will be 52 * initialised using the values contained in 'oldtls' and 'oldtls' 53 * will be freed. This is typically used when initialising a thread 54 * library to migrate from using the initial bootstrap TLS block 55 * created by rtld to one which contains suitable thread library 56 * private data. 57 * 58 * The value returned from this function is suitable for installing 59 * directly into the thread pointer register. 60 */ 61 void *_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 62 __exported; 63 64 /* 65 * Free a TLS block allocated using _rtld_allocate_tls(). The tcbsize 66 * and tcbalign parameters must be the same as those used to allocate 67 * the block. 68 */ 69 void _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) __exported; 70 71 #endif 72