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__clone.S revision 1.3 
      1 /*	$NetBSD: __clone.S,v 1.3 2008/04/28 20:22:55 martin Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2001 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Jason R. Thorpe.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/errno.h>
     33 
     34 #include "SYS.h"
     35 
     36 #ifdef WEAK_ALIAS
     37 WEAK_ALIAS(clone, __clone)
     38 #endif
     39 
     40 /*
     41  * int __clone(int (*fn)(void *), void *stack, int flags, void *arg);
     42  */
     43 LEAF(__clone, 4)
     44 	br	pv, 1f
     45 1:	LDGP(pv)
     46 
     47 	/*
     48 	 * Sanity checks: func and stack may not be NULL.
     49 	 */
     50 	beq	a0, 9f
     51 	beq	a1, 9f
     52 
     53 	/*
     54 	 * We need to be able to get at the func and arg arguments
     55 	 * in the child.  Luckily, we have a convenient place to
     56 	 * do this; the child's stack.
     57 	 */
     58 	subq	a1, 16, a1
     59 	stq	a0, 0(a1)
     60 	stq	a3, 8(a1)
     61 
     62 	/*
     63 	 * The system call expects (flags, stack).
     64 	 */
     65 	mov	a2, a0
     66 	CALLSYS_ERROR(__clone)
     67 
     68 	beq	a4, 8f		/* a4 (rv[1]) == 0, parent, child pid in v0 */
     69 
     70 	/*
     71 	 * Fetch the function and argument from the new stack, and
     72 	 * pop it back.
     73 	 */
     74 	ldq	pv, 0(sp)
     75 	ldq	a0, 8(sp)
     76 	addq	sp, 16, sp
     77 
     78 	/* Call the clone's entry point. */
     79 	CALL((pv))
     80 
     81 	/* Pass return value to _exit(). */
     82 	mov	v0, a0
     83 	CALL(_exit)
     84 
     85 	/* NOTREACHED */
     86 
     87 8:	RET
     88 
     89 9:	ldiq	v0, EINVAL
     90 	jmp	zero, __cerror
     91 	END(__clone)
     92