/*-
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * William Jolitz.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      $OpenBSD: SYS.h,v 1.28 2023/12/10 16:45:51 deraadt Exp $
 */

#include "DEFS.h"
#include <sys/syscall.h>

#define TCB_OFFSET_ERRNO        16

/*
 * Design note:
 *
 * System calls entry points are really named _thread_sys_{syscall},
 * and weakly aliased to the name {syscall}. This allows the thread
 * library to replace system calls at link time.
 */

/* Use both _thread_sys_{syscall} and [weak] {syscall}. */

#define SYSENTRY(x)                                     \
                        ENTRY(_thread_sys_##x);         \
                        WEAK_ALIAS(x, _thread_sys_##x)
#define SYSENTRY_HIDDEN(x)                              \
                        ENTRY(_thread_sys_ ## x)
#define __END_HIDDEN(x) END(_thread_sys_ ## x);                 \
                        _HIDDEN_FALIAS(x,_thread_sys_ ## x);    \
                        END(_HIDDEN(x))
#define __END(x)        __END_HIDDEN(x); END(x)

#define __DO_SYSCALL(x)                                 \
                        movl $(SYS_ ## x),%eax;         \
                97:     int $0x80;                      \
                        PINSYSCALL(SYS_ ## x, 97b)


#define SET_ERRNO()                                     \
        movl    %eax,%gs:(TCB_OFFSET_ERRNO);            \
        movl    $-1, %eax;                              \
        movl    $-1, %edx       /* for lseek */
#define HANDLE_ERRNO()                                  \
        jnc     99f;                                    \
        SET_ERRNO();                                    \
        99:

/* perform a syscall */
#define _SYSCALL_NOERROR(x,y)                           \
                SYSENTRY(x);                            \
                        __DO_SYSCALL(y);
#define _SYSCALL_HIDDEN_NOERROR(x,y)                    \
                SYSENTRY_HIDDEN(x);                     \
                        __DO_SYSCALL(y);

#define SYSCALL_NOERROR(x)                              \
                _SYSCALL_NOERROR(x,x)

/* perform a syscall, set errno */
#define _SYSCALL(x,y)                                   \
                        .text;                          \
                        .align 2;                       \
                _SYSCALL_NOERROR(x,y)                   \
                        HANDLE_ERRNO()
#define _SYSCALL_HIDDEN(x,y)                            \
                        .text;                          \
                        .align 2;                       \
                _SYSCALL_HIDDEN_NOERROR(x,y)            \
                        HANDLE_ERRNO()

#define SYSCALL(x)                                      \
                _SYSCALL(x,x)
#define SYSCALL_HIDDEN(x)                               \
                _SYSCALL_HIDDEN(x,y)

/* perform a syscall, return */
#define PSEUDO_NOERROR(x,y)                             \
                _SYSCALL_NOERROR(x,y);                  \
                        ret;                            \
                __END(x)

/* perform a syscall, set errno, return */
#define PSEUDO(x,y)                                     \
                _SYSCALL(x,y);                          \
                        ret;                            \
                __END(x)
#define PSEUDO_HIDDEN(x,y)                              \
                _SYSCALL_HIDDEN(x,y);                   \
                        ret;                            \
                __END_HIDDEN(x)

/* perform a syscall with the same name, set errno, return */
#define RSYSCALL(x)                                     \
                        PSEUDO(x,x);
#define RSYSCALL_HIDDEN(x)                              \
                        PSEUDO_HIDDEN(x,x)
#define SYSCALL_END(x)  __END(x)
#define SYSCALL_END_HIDDEN(x)                           \
                        __END_HIDDEN(x)