xref: /freebsd/lib/libthr/arch/i386/include/pthread_md.h (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
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  * $FreeBSD$
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	CPU_SPINWAIT		__asm __volatile("pause")
41 
42 #define	DTV_OFFSET		offsetof(struct tcb, tcb_dtv)
43 
44 /*
45  * Variant II tcb, first two members are required by rtld,
46  * %gs points to the structure.
47  */
48 struct tcb {
49 	struct tcb		*tcb_self;	/* required by rtld */
50 	void			*tcb_dtv;	/* required by rtld */
51 	struct pthread		*tcb_thread;
52 };
53 
54 /*
55  * Evaluates to the byte offset of the per-tcb variable name.
56  */
57 #define	__tcb_offset(name)	__offsetof(struct tcb, name)
58 
59 /*
60  * Evaluates to the type of the per-tcb variable name.
61  */
62 #define	__tcb_type(name)	__typeof(((struct tcb *)0)->name)
63 
64 /*
65  * Evaluates to the value of the per-tcb variable name.
66  */
67 #define	TCB_GET32(name) ({					\
68 	__tcb_type(name) __result;				\
69 								\
70 	u_int __i;						\
71 	__asm __volatile("movl %%gs:%1, %0"			\
72 	    : "=r" (__i)					\
73 	    : "m" (*(u_int *)(__tcb_offset(name))));		\
74 	__result = (__tcb_type(name))__i;			\
75 								\
76 	__result;						\
77 })
78 
79 /*
80  * The constructors.
81  */
82 struct tcb	*_tcb_ctor(struct pthread *, int);
83 void		_tcb_dtor(struct tcb *tcb);
84 
85 /* Called from the thread to set its private data. */
86 static __inline void
87 _tcb_set(struct tcb *tcb)
88 {
89  	i386_set_gsbase(tcb);
90 }
91 
92 /* Get the current kcb. */
93 static __inline struct tcb *
94 _tcb_get(void)
95 {
96 	return (TCB_GET32(tcb_self));
97 }
98 
99 /* Get the current thread. */
100 static __inline struct pthread *
101 _get_curthread(void)
102 {
103 	return (TCB_GET32(tcb_thread));
104 }
105 #endif
106