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 1.25 2016/05/07 19:05:21 guenther Exp $ 33 */ 34 35 #include <machine/asm.h> 36 #include <sys/syscall.h> 37 38 #define TCB_OFFSET_ERRNO 16 39 40 /* 41 * We define a hidden alias with the prefix "_libc_" for each global symbol 42 * that may be used internally. By referencing _libc_x instead of x, other 43 * parts of libc prevent overriding by the application and avoid unnecessary 44 * relocations. 45 */ 46 #define _HIDDEN(x) _libc_##x 47 #define _HIDDEN_ALIAS(x,y) \ 48 STRONG_ALIAS(_HIDDEN(x),y); \ 49 .hidden _HIDDEN(x) 50 #define _HIDDEN_FALIAS(x,y) \ 51 _HIDDEN_ALIAS(x,y); \ 52 .type _HIDDEN(x),@function 53 54 /* 55 * For functions implemented in ASM that aren't syscalls. 56 * END_STRONG(x) Like DEF_STRONG() in C; for standard/reserved C names 57 * END_WEAK(x) Like DEF_WEAK() in C; for non-ISO C names 58 */ 59 #define END_STRONG(x) END(x); _HIDDEN_FALIAS(x,x); END(_HIDDEN(x)) 60 #define END_WEAK(x) END_STRONG(x); .weak x 61 62 63 /* 64 * Design note: 65 * 66 * System calls entry points are really named _thread_sys_{syscall}, 67 * and weakly aliased to the name {syscall}. This allows the thread 68 * library to replace system calls at link time. 69 */ 70 71 /* Use both _thread_sys_{syscall} and [weak] {syscall}. */ 72 73 #define SYSENTRY(x) \ 74 ENTRY(_thread_sys_##x); \ 75 WEAK_ALIAS(x, _thread_sys_##x) 76 #define SYSENTRY_HIDDEN(x) \ 77 ENTRY(_thread_sys_ ## x) 78 #define __END_HIDDEN(x) END(_thread_sys_ ## x); \ 79 _HIDDEN_FALIAS(x,_thread_sys_ ## x); \ 80 END(_HIDDEN(x)) 81 #define __END(x) __END_HIDDEN(x); END(x) 82 83 #define __DO_SYSCALL(x) \ 84 movl $(SYS_ ## x),%eax; \ 85 int $0x80 86 87 #define SET_ERRNO() \ 88 movl %eax,%gs:(TCB_OFFSET_ERRNO); \ 89 movl $-1, %eax; \ 90 movl $-1, %edx /* for lseek */ 91 #define HANDLE_ERRNO() \ 92 jnc,pt 99f; \ 93 SET_ERRNO(); \ 94 99: 95 96 /* perform a syscall */ 97 #define _SYSCALL_NOERROR(x,y) \ 98 SYSENTRY(x); \ 99 __DO_SYSCALL(y); 100 #define _SYSCALL_HIDDEN_NOERROR(x,y) \ 101 SYSENTRY_HIDDEN(x); \ 102 __DO_SYSCALL(y); 103 104 #define SYSCALL_NOERROR(x) \ 105 _SYSCALL_NOERROR(x,x) 106 107 /* perform a syscall, set errno */ 108 #define _SYSCALL(x,y) \ 109 .text; \ 110 .align 2; \ 111 _SYSCALL_NOERROR(x,y) \ 112 HANDLE_ERRNO() 113 #define _SYSCALL_HIDDEN(x,y) \ 114 .text; \ 115 .align 2; \ 116 _SYSCALL_HIDDEN_NOERROR(x,y) \ 117 HANDLE_ERRNO() 118 119 #define SYSCALL(x) \ 120 _SYSCALL(x,x) 121 #define SYSCALL_HIDDEN(x) \ 122 _SYSCALL_HIDDEN(x,y) 123 124 /* perform a syscall, return */ 125 #define PSEUDO_NOERROR(x,y) \ 126 _SYSCALL_NOERROR(x,y); \ 127 ret; \ 128 __END(x) 129 130 /* perform a syscall, set errno, return */ 131 #define PSEUDO(x,y) \ 132 _SYSCALL(x,y); \ 133 ret; \ 134 __END(x) 135 #define PSEUDO_HIDDEN(x,y) \ 136 _SYSCALL_HIDDEN(x,y); \ 137 ret; \ 138 __END_HIDDEN(x) 139 140 /* perform a syscall with the same name, set errno, return */ 141 #define RSYSCALL(x) \ 142 PSEUDO(x,x); 143 #define RSYSCALL_HIDDEN(x) \ 144 PSEUDO_HIDDEN(x,x) 145 #define SYSCALL_END(x) __END(x) 146 #define SYSCALL_END_HIDDEN(x) \ 147 __END_HIDDEN(x) 148