pthread_md.h revision 144518 
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 144518 2005-04-02 01:20:00Z davidxu $
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
42/*
43 * Variant II tcb, first two members are required by rtld,
44 * %gs points to the structure.
45 */
46struct tcb {
47	struct tcb		*tcb_self;	/* required by rtld */
48	void			*tcb_dtv;	/* required by rtld */
49	struct pthread		*tcb_thread;
50	int			tcb_ldt;
51};
52
53/*
54 * Evaluates to the byte offset of the per-tcb variable name.
55 */
56#define	__tcb_offset(name)	__offsetof(struct tcb, name)
57
58/*
59 * Evaluates to the type of the per-tcb variable name.
60 */
61#define	__tcb_type(name)	__typeof(((struct tcb *)0)->name)
62
63/*
64 * Evaluates to the value of the per-tcb variable name.
65 */
66#define	TCB_GET32(name) ({					\
67	__tcb_type(name) __result;				\
68								\
69	u_int __i;						\
70	__asm __volatile("movl %%gs:%1, %0"			\
71	    : "=r" (__i)					\
72	    : "m" (*(u_int *)(__tcb_offset(name))));		\
73	__result = (__tcb_type(name))__i;			\
74								\
75	__result;						\
76})
77
78/*
79 * The constructors.
80 */
81struct tcb	*_tcb_ctor(struct pthread *, int);
82void		_tcb_dtor(struct tcb *tcb);
83
84/* Called from the thread to set its private data. */
85static __inline void
86_tcb_set(struct tcb *tcb)
87{
88#ifndef COMPAT_32BIT
89	int val;
90
91	val = (tcb->tcb_ldt << 3) | 7;
92	__asm __volatile("movl %0, %%gs" : : "r" (val));
93#else
94	_amd64_set_gsbase(tcb);
95#endif
96
97}
98
99/* Get the current kcb. */
100static __inline struct tcb *
101_tcb_get(void)
102{
103	return (TCB_GET32(tcb_self));
104}
105
106extern struct pthread *_thr_initial;
107
108/* Get the current thread. */
109static __inline struct pthread *
110_get_curthread(void)
111{
112	if (_thr_initial)
113		return (TCB_GET32(tcb_thread));
114	return (NULL);
115}
116#endif
117