xref: /openbsd-src/lib/libc/arch/i386/SYS.h (revision d13be5d47e4149db2549a9828e244d59dbc43f15)
1 /*-
2  * Copyright (c) 1990 The Regents of the University of California.
3  * All rights reserved.
4  *
5  * This code is derived from software contributed to Berkeley by
6  * William Jolitz.
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  * 3. Neither the name of the University nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  *
32  *	$OpenBSD: SYS.h,v 1.17 2011/04/04 12:42:39 guenther Exp $
33  */
34 
35 #include <machine/asm.h>
36 #include <sys/syscall.h>
37 
38 /*
39  * Design note:
40  *
41  * System calls entry points are really named _thread_sys_{syscall},
42  * and weakly aliased to the name {syscall}. This allows the thread
43  * library to replace system calls at link time.
44  */
45 
46 /* Use both _thread_sys_{syscall} and [weak] {syscall}. */
47 
48 #ifdef __STDC__
49 #define	SYSENTRY(x)					\
50 			ENTRY(_thread_sys_ ## x);	\
51 			.weak _C_LABEL(x);		\
52 			_C_LABEL(x) = _C_LABEL(_thread_sys_ ## x)
53 #else /* ! __STDC__ */
54 #define	SYSENTRY(x)					\
55 			ENTRY(_thread_sys_/**/x);	\
56 			.weak _C_LABEL(x);		\
57 			_C_LABEL(x) = _C_LABEL(_thread_sys_/**/x)
58 #endif /* ! __STDC__ */
59 
60 #ifdef __STDC__
61 #define	__DO_SYSCALL(x)					\
62 			movl $(SYS_ ## x),%eax;		\
63 			int $0x80
64 #else /* ! __STDC__ */
65 #define	__DO_SYSCALL(x)					\
66 			movl $(SYS_/**/x),%eax;		\
67 			int $0x80
68 #endif /* ! __STDC__ */
69 
70 #define CERROR		_C_LABEL(__cerror)
71 #define _CERROR		_C_LABEL(___cerror)
72 #define CURBRK		_C_LABEL(__curbrk)
73 
74 /* perform a syscall */
75 #define	_SYSCALL_NOERROR(x,y)				\
76 		SYSENTRY(x);				\
77 			__DO_SYSCALL(y);
78 
79 #define	SYSCALL_NOERROR(x)				\
80 		_SYSCALL_NOERROR(x,x)
81 
82 /* perform a syscall, set errno */
83 #ifdef PIC
84 #define	_SYSCALL(x,y)					\
85 			.text;				\
86 			.align 2;			\
87 		2:	PIC_PROLOGUE;			\
88 			movl PIC_GOT(CERROR), %ecx;	\
89 			PIC_EPILOGUE;			\
90 			jmp *%ecx;			\
91 		_SYSCALL_NOERROR(x,y)			\
92 			jc 2b
93 #else
94 #define	_SYSCALL(x,y)					\
95 			.text;				\
96 			.align 2;			\
97 		2:					\
98 			jmp PIC_PLT(CERROR);		\
99 		_SYSCALL_NOERROR(x,y)			\
100 			jc 2b
101 #endif
102 
103 #define	SYSCALL(x)					\
104 		_SYSCALL(x,x)
105 
106 /* perform a syscall, return */
107 #define	PSEUDO_NOERROR(x,y)				\
108 		_SYSCALL_NOERROR(x,y);			\
109 			ret
110 
111 /* perform a syscall, set errno, return */
112 #define	PSEUDO(x,y)					\
113 		_SYSCALL(x,y);				\
114 			ret
115 
116 /* perform a syscall with the same name, set errno, return */
117 #define	RSYSCALL(x)					\
118 			PSEUDO(x,x);
119 
120 	.globl	CERROR
121