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__clone.S revision 1.6 
      1 /*	$NetBSD: __clone.S,v 1.6 2008/04/28 20:22:57 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 ENTRY(__clone)
     44 	save	%sp, -CCFSZ, %sp
     45 
     46 	/*
     47 	 * Sanity checks: func and stack may not be NULL.
     48 	 */
     49 	tst	%i0
     50 	be	8f		! func == NULL, bail
     51 	 orcc	%i1, %g0, %o1	! setup stack arg for syscall, test
     52 	be	8f		! stack == NULL, bail
     53 	 mov	%i2, %o0	! setup flags arg for syscall
     54 
     55 	/*
     56 	 * Allocate "caller's" frame in the child stack as ABI
     57 	 * requires.
     58 	 *
     59 	 * We pass the function and the argument to the child by
     60 	 * stashing them at the bottom of the frame.  There they are
     61 	 * safe from window spill would we need to take one as it's
     62 	 * below the window save area.
     63 	 */
     64 	sub	%o1, CCFSZ, %o1	! make space on the child's stack
     65 	st	%i0, [%o1+CCFSZ-8]	! save func
     66 	st	%i3, [%o1+CCFSZ-4]	! save arg
     67 
     68 	/*
     69 	 * Args are now set up for system call as (flags, stack).
     70 	 */
     71 	mov	SYS___clone, %g1
     72 	t	ST_SYSCALL
     73 	bcs	9f
     74 	 tst	%o1		! %o1 (rv[1]) == 0 in parent
     75 
     76 1:	bz	2f		! yes, parent
     77 	 ld	[%sp+CCFSZ-8], %l0	! grab the function...
     78 	call	%l0 		! Call the clone's entry point.
     79 	 ld	[%sp+CCFSZ-4], %o0	! ...and the argument from the stack
     80 
     81 	CALL(_C_LABEL(_exit))
     82 	/* NOTREACHED */
     83 
     84 2:	ret
     85 	 restore %g0, %o0, %o0
     86 
     87 8:	restore	%g0, EINVAL, %o0
     88 	ERROR()
     89 	/* NOTREACHED */
     90 
     91 9:	restore %g0, %o0, %o0
     92 	ERROR()
     93 	/* NOTREACHED */
     94