xref: /openbsd/lib/libc/arch/i386/SYS.h (revision 8529ddd3)
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 1.20 2015/04/07 01:27:06 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 #define	SYSENTRY(x)					\
49 			ENTRY(_thread_sys_ ## x);	\
50 			.weak _C_LABEL(x);		\
51 			_C_LABEL(x) = _C_LABEL(_thread_sys_ ## x)
52 #define	SYSENTRY_HIDDEN(x)				\
53 			ENTRY(_thread_sys_ ## x)
54 
55 #define	__DO_SYSCALL(x)					\
56 			movl $(SYS_ ## x),%eax;		\
57 			int $0x80
58 
59 #define CERROR		_C_LABEL(__cerror)
60 #define _CERROR		_C_LABEL(___cerror)
61 #define CURBRK		_C_LABEL(__curbrk)
62 
63 /* perform a syscall */
64 #define	_SYSCALL_NOERROR(x,y)				\
65 		SYSENTRY(x);				\
66 			__DO_SYSCALL(y);
67 #define	_SYSCALL_HIDDEN_NOERROR(x,y)			\
68 		SYSENTRY_HIDDEN(x);			\
69 			__DO_SYSCALL(y);
70 
71 #define	SYSCALL_NOERROR(x)				\
72 		_SYSCALL_NOERROR(x,x)
73 
74 /* perform a syscall, set errno */
75 #ifdef __PIC__
76 #define	_SYSCALL(x,y)					\
77 			.text;				\
78 			.align 2;			\
79 		2:	PIC_PROLOGUE;			\
80 			movl PIC_GOT(CERROR), %ecx;	\
81 			PIC_EPILOGUE;			\
82 			jmp *%ecx;			\
83 		_SYSCALL_NOERROR(x,y)			\
84 			jc 2b
85 #define	_SYSCALL_HIDDEN(x,y)				\
86 			.text;				\
87 			.align 2;			\
88 		2:	PIC_PROLOGUE;			\
89 			movl PIC_GOT(CERROR), %ecx;	\
90 			PIC_EPILOGUE;			\
91 			jmp *%ecx;			\
92 		_SYSCALL_HIDDEN_NOERROR(x,y)		\
93 			jc 2b
94 #else
95 #define	_SYSCALL(x,y)					\
96 			.text;				\
97 			.align 2;			\
98 		2:					\
99 			jmp PIC_PLT(CERROR);		\
100 		_SYSCALL_NOERROR(x,y)			\
101 			jc 2b
102 #define	_SYSCALL_HIDDEN(x,y)				\
103 			.text;				\
104 			.align 2;			\
105 		2:					\
106 			jmp PIC_PLT(CERROR);		\
107 		_SYSCALL_HIDDEN_NOERROR(x,y)		\
108 			jc 2b
109 #endif
110 
111 #define	SYSCALL(x)					\
112 		_SYSCALL(x,x)
113 
114 /* perform a syscall, return */
115 #define	PSEUDO_NOERROR(x,y)				\
116 		_SYSCALL_NOERROR(x,y);			\
117 			ret
118 
119 /* perform a syscall, set errno, return */
120 #define	PSEUDO(x,y)					\
121 		_SYSCALL(x,y);				\
122 			ret
123 #define	PSEUDO_HIDDEN(x,y)				\
124 		_SYSCALL_HIDDEN(x,y);			\
125 			ret
126 
127 /* perform a syscall with the same name, set errno, return */
128 #define	RSYSCALL(x)					\
129 			PSEUDO(x,x);
130 #define	RSYSCALL_HIDDEN(x)				\
131 			PSEUDO_HIDDEN(x,x)
132 
133 	.globl	CERROR
134