pthread_md.h revision 145040 
1/*-
2 * Copyright (c) 2002 Daniel Eischen <deischen@freebsd.org>.
3 * Copyright (c) 2005 David Xu <davidxu@freebsd.org>.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 *
27 * $FreeBSD: head/lib/libthr/arch/i386/include/pthread_md.h 145040 2005-04-14 00:44:07Z peter $
28 */
29
30/*
31 * Machine-dependent thread prototypes/definitions.
32 */
33#ifndef _PTHREAD_MD_H_
34#define	_PTHREAD_MD_H_
35
36#include <stddef.h>
37#include <sys/types.h>
38#include <machine/sysarch.h>
39
40#define	DTV_OFFSET		offsetof(struct tcb, tcb_dtv)
41
42extern int _thr_using_setbase;
43
44/*
45 * Variant II tcb, first two members are required by rtld,
46 * %gs points to the structure.
47 */
48struct tcb {
49	struct tcb		*tcb_self;	/* required by rtld */
50	void			*tcb_dtv;	/* required by rtld */
51	struct pthread		*tcb_thread;
52	int			tcb_ldt;
53};
54
55/*
56 * Evaluates to the byte offset of the per-tcb variable name.
57 */
58#define	__tcb_offset(name)	__offsetof(struct tcb, name)
59
60/*
61 * Evaluates to the type of the per-tcb variable name.
62 */
63#define	__tcb_type(name)	__typeof(((struct tcb *)0)->name)
64
65/*
66 * Evaluates to the value of the per-tcb variable name.
67 */
68#define	TCB_GET32(name) ({					\
69	__tcb_type(name) __result;				\
70								\
71	u_int __i;						\
72	__asm __volatile("movl %%gs:%1, %0"			\
73	    : "=r" (__i)					\
74	    : "m" (*(u_int *)(__tcb_offset(name))));		\
75	__result = (__tcb_type(name))__i;			\
76								\
77	__result;						\
78})
79
80/*
81 * The constructors.
82 */
83struct tcb	*_tcb_ctor(struct pthread *, int);
84void		_tcb_dtor(struct tcb *tcb);
85
86/* Called from the thread to set its private data. */
87static __inline void
88_tcb_set(struct tcb *tcb)
89{
90#ifndef COMPAT_32BIT
91	int val;
92
93 	if (_thr_using_setbase == 1) {
94 		i386_set_gsbase(tcb);
95 	} else {
96		val = (tcb->tcb_ldt << 3) | 7;
97		__asm __volatile("movl %0, %%gs" : : "r" (val));
98 	}
99#else
100	_amd64_set_gsbase(tcb);
101#endif
102
103}
104
105/* Get the current kcb. */
106static __inline struct tcb *
107_tcb_get(void)
108{
109	return (TCB_GET32(tcb_self));
110}
111
112extern struct pthread *_thr_initial;
113
114/* Get the current thread. */
115static __inline struct pthread *
116_get_curthread(void)
117{
118	if (_thr_initial)
119		return (TCB_GET32(tcb_thread));
120	return (NULL);
121}
122#endif
123