root/lib/libsys/aarch64/SYS.h
/*-
 * Copyright (c) 2014 Andrew Turner
 * Copyright (c) 2015 The FreeBSD Foundation
 *
 * This software was developed by Andrew Turner under
 * sponsorship from the FreeBSD Foundation.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 */

#include <sys/syscall.h>
#include <machine/asm.h>

#define _SYSCALL(name)                                          \
        mov     x8, SYS_ ## name;                               \
        svc     0

#ifndef _SYSCALL_BODY
/*
 * Conditional jumps can only go up to one megabyte in either
 * direction, and cerror can be located anywhere, so we have
 * to jump around to use more capable unconditional branch
 * instruction.
 */
#define _SYSCALL_BODY(name)                                     \
        _SYSCALL(name);                                         \
        b.cs    1f;                                             \
        ret;                                                    \
1:      b       cerror
#endif

#define PSEUDO(name)                                            \
ENTRY(__sys_##name);                                            \
        WEAK_REFERENCE(__sys_##name, _##name);                  \
        _SYSCALL_BODY(name);                                    \
END(__sys_##name)

#define RSYSCALL(name)                                          \
ENTRY(__sys_##name);                                            \
        WEAK_REFERENCE(__sys_##name, name);                     \
        WEAK_REFERENCE(__sys_##name, _##name);                  \
        _SYSCALL_BODY(name);                                    \
END(__sys_##name)