xref: /freebsd/sys/x86/include/tls.h (revision aef025fc9b6c8b06677086a93c866ee09622f6fa)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (C) 2003 David Xu <davidxu@freebsd.org>
5  * Copyright (c) 2001 Daniel Eischen <deischen@freebsd.org>
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Neither the name of the author nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #ifndef _MACHINE_TLS_H_
31 #define	_MACHINE_TLS_H_
32 
33 #include <x86/sysarch.h>
34 
35 #define	TLS_VARIANT_II
36 
37 struct pthread;
38 
39 struct dtv_slot {
40 	char			*dtvs_tls;
41 };
42 
43 struct dtv {
44 	uintptr_t		dtv_gen;
45 	uintptr_t		dtv_size;
46 	struct dtv_slot		dtv_slots[];
47 };
48 
49 /*
50  * Variant II tcb, first two members are required by rtld,
51  * %fs (amd64) / %gs (i386) points to the structure.
52  */
53 struct tcb {
54 	struct tcb		*tcb_self;	/* required by rtld */
55 	struct dtv		*tcb_dtv;	/* required by rtld */
56 	struct pthread		*tcb_thread;
57 };
58 
59 #define	TLS_DTV_OFFSET	0
60 #ifdef __amd64__
61 #define	TLS_TCB_ALIGN	16
62 #else
63 #define	TLS_TCB_ALIGN	4
64 #endif
65 #define	TLS_TCB_SIZE	sizeof(struct tcb)
66 #define	TLS_TP_OFFSET	0
67 
68 static __inline void
_tcb_set(struct tcb * tcb)69 _tcb_set(struct tcb *tcb)
70 {
71 #ifdef __amd64__
72 	amd64_set_tlsbase(tcb);
73 #else
74  	i386_set_gsbase(tcb);
75 #endif
76 }
77 
78 static __inline struct tcb *
_tcb_get(void)79 _tcb_get(void)
80 {
81 	struct tcb *tcb;
82 
83 #ifdef __amd64__
84 	__asm __volatile("movq %%fs:0, %0" : "=r" (tcb));
85 #else
86 	__asm __volatile("movl %%gs:0, %0" : "=r" (tcb));
87 #endif
88 	return (tcb);
89 }
90 
91 #endif /* !_MACHINE_TLS_H_ */
92