/*      $NetBSD: __clone.S,v 1.6 2008/04/28 20:22:57 martin Exp $       */

/*-     
 * Copyright (c) 2001 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe.
 *      
 * 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/errno.h>

#include "SYS.h"

#ifdef WEAK_ALIAS
WEAK_ALIAS(clone, __clone)
#endif

/*
 * int __clone(int (*fn)(void *), void *stack, int flags, void *arg);
 */
ENTRY(__clone)
        save    %sp, -CCFSZ, %sp

        /*
         * Sanity checks: func and stack may not be NULL.
         */
        tst     %i0
        be      8f              ! func == NULL, bail
         orcc   %i1, %g0, %o1   ! setup stack arg for syscall, test
        be      8f              ! stack == NULL, bail
         mov    %i2, %o0        ! setup flags arg for syscall

        /*
         * Allocate "caller's" frame in the child stack as ABI
         * requires.
         *
         * We pass the function and the argument to the child by
         * stashing them at the bottom of the frame.  There they are
         * safe from window spill would we need to take one as it's
         * below the window save area.
         */
        sub     %o1, CCFSZ, %o1 ! make space on the child's stack
        st      %i0, [%o1+CCFSZ-8]      ! save func
        st      %i3, [%o1+CCFSZ-4]      ! save arg

        /*
         * Args are now set up for system call as (flags, stack).
         */
        mov     SYS___clone, %g1
        t       ST_SYSCALL
        bcs     9f
         tst    %o1             ! %o1 (rv[1]) == 0 in parent

1:      bz      2f              ! yes, parent
         ld     [%sp+CCFSZ-8], %l0      ! grab the function...
        call    %l0             ! Call the clone's entry point.
         ld     [%sp+CCFSZ-4], %o0      ! ...and the argument from the stack

        CALL(_C_LABEL(_exit))
        /* NOTREACHED */

2:      ret
         restore %g0, %o0, %o0

8:      restore %g0, EINVAL, %o0
        ERROR()
        /* NOTREACHED */

9:      restore %g0, %o0, %o0
        ERROR()
        /* NOTREACHED */