/* $NetBSD: __clone.S,v 1.2 2018/11/22 08:30:58 ryo Exp $ */

/*-
* Copyright (c) 2014 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Matt Thomas of 3am Software Foundry.
*
* 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.h"
#include <sys/errno.h>

WEAK_ALIAS(clone, __clone)

/*
* int __clone(int (*fn)(void *), void *stack, int flags, void *arg);
*/
ENTRY(__clone)

       /* test stack and function are not null */
       cbz     x0, .Leinval
       cbz     x1, .Leinval

       /* place the arg and func onto the child's stack */
       stp     x3, x0, [x1, #-16]!

       /* syscall expects (flags, stack) */
       mov     x0, x2

       SYSTRAP(__clone)
       _INVOKE_CERROR()

       /*
        * x1 and x0 are the same as from fork:
        * x1 == 0 in parent process, x1 == 1 in child process.
        * x0 == pid of child in parent, x0 == pid of parent in child.
        */
       /* if this is the parent then just return the pid */
       cbz     x1, 1f

       /*
        * This is the child
        * load the function and arg off the stack
        */
       ldp     x0, x1, [sp], #16

       /* call the function */
       blr     x1

       /* call _exit with the returned value */
       bl      _C_LABEL(_exit)
1:      ret
Leinval:
       mov     x0, #EINVAL
       b       _C_LABEL(__cerror)
END(__clone)