src/lib/libc/arch/i386/SYS.h

   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 1.16 2006/04/24 14:28:34 drahn 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 CURBRK          _C_LABEL(__curbrk)
  72
  73 /* perform a syscall */
  74 #define _SYSCALL_NOERROR(x,y)                           \
  75                 SYSENTRY(x);                            \
  76                         __DO_SYSCALL(y);
  77
  78 #define SYSCALL_NOERROR(x)                              \
  79                 _SYSCALL_NOERROR(x,x)
  80
  81 /* perform a syscall, set errno */
  82 #ifdef PIC
  83 #define _SYSCALL(x,y)                                   \
  84                         .text;                          \
  85                         .align 2;                       \
  86                 2:      PIC_PROLOGUE;                   \
  87                         movl PIC_GOT(CERROR), %ecx;     \
  88                         PIC_EPILOGUE;                   \
  89                         jmp *%ecx;                      \
  90                 _SYSCALL_NOERROR(x,y)                   \
  91                         jc 2b
  92 #else
  93 #define _SYSCALL(x,y)                                   \
  94                         .text;                          \
  95                         .align 2;                       \
  96                 2:                                      \
  97                         jmp PIC_PLT(CERROR);            \
  98                 _SYSCALL_NOERROR(x,y)                   \
  99                         jc 2b
 100 #endif
 101
 102 #define SYSCALL(x)                                      \
 103                 _SYSCALL(x,x)
 104
 105 /* perform a syscall, return */
 106 #define PSEUDO_NOERROR(x,y)                             \
 107                 _SYSCALL_NOERROR(x,y);                  \
 108                         ret
 109
 110 /* perform a syscall, set errno, return */
 111 #define PSEUDO(x,y)                                     \
 112                 _SYSCALL(x,y);                          \
 113                         ret
 114
 115 /* perform a syscall with the same name, set errno, return */
 116 #define RSYSCALL(x)                                     \
 117                         PSEUDO(x,x);
 118
 119         .globl  CERROR