1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2002 Daniel Eischen <deischen@freebsd.org>.
5  * Copyright (c) 2005 David Xu <davidxu@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. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
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  * $FreeBSD$
30  */
31 
32 /*
33  * Machine-dependent thread prototypes/definitions.
34  */
35 #ifndef _PTHREAD_MD_H_
36 #define	_PTHREAD_MD_H_
37 
38 #include <stddef.h>
39 #include <sys/types.h>
40 #include <machine/sysarch.h>
41 
42 #define	CPU_SPINWAIT		__asm __volatile("pause")
43 
44 #define	DTV_OFFSET		offsetof(struct tcb, tcb_dtv)
45 
46 /*
47  * Variant II tcb, first two members are required by rtld,
48  * %gs points to the structure.
49  */
50 struct tcb {
51 	struct tcb		*tcb_self;	/* required by rtld */
52 	void			*tcb_dtv;	/* required by rtld */
53 	struct pthread		*tcb_thread;
54 };
55 
56 /*
57  * Evaluates to the byte offset of the per-tcb variable name.
58  */
59 #define	__tcb_offset(name)	__offsetof(struct tcb, name)
60 
61 /*
62  * Evaluates to the type of the per-tcb variable name.
63  */
64 #define	__tcb_type(name)	__typeof(((struct tcb *)0)->name)
65 
66 /*
67  * Evaluates to the value of the per-tcb variable name.
68  */
69 #define	TCB_GET32(name) ({					\
70 	__tcb_type(name) __result;				\
71 								\
72 	u_int __i;						\
73 	__asm __volatile("movl %%gs:%1, %0"			\
74 	    : "=r" (__i)					\
75 	    : "m" (*(volatile u_int *)(__tcb_offset(name))));	\
76 	__result = (__tcb_type(name))__i;			\
77 								\
78 	__result;						\
79 })
80 
81 /* Called from the thread to set its private data. */
82 static __inline void
83 _tcb_set(struct tcb *tcb)
84 {
85  	i386_set_gsbase(tcb);
86 }
87 
88 /* Get the current kcb. */
89 static __inline struct tcb *
90 _tcb_get(void)
91 {
92 	return (TCB_GET32(tcb_self));
93 }
94 
95 /* Get the current thread. */
96 static __inline struct pthread *
97 _get_curthread(void)
98 {
99 	return (TCB_GET32(tcb_thread));
100 }
101 
102 #define HAS__UMTX_OP_ERR	1
103 
104 #endif
105