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__clone.S revision 1.2 
      1 /* $NetBSD: __clone.S,v 1.2 2002/08/17 19:54:31 thorpej Exp $ */
      2 
      3 /*
      4  * Copyright (c) 2001 Christopher Gilbert
      5  * All rights reserved.
      6  *
      7  * 1. Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  * 2. Redistributions in binary form must reproduce the above copyright
     10  *    notice, this list of conditions and the following disclaimer in the
     11  *    documentation and/or other materials provided with the distribution.
     12  * 3. The name of the company nor the name of the author may be used to
     13  *    endorse or promote products derived from this software without specific
     14  *    prior written permission.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
     17  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
     18  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     19  * IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
     20  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
     21  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
     22  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  */
     28 
     29 #include <machine/asm.h>
     30 #include <sys/errno.h>
     31 #include "SYS.h"
     32 
     33 #ifdef WEAK_ALIAS
     34 WEAK_ALIAS(clone, __clone)
     35 #endif
     36 
     37 /*
     38  * int __clone(int (*fn)(void *), void *stack, int flags, void *arg);
     39  */
     40 ENTRY(__clone)
     41 
     42 	/* test stack and function are not null */
     43 	teq	r0, #0x00
     44 	teqne	r1, #0x00
     45 	beq	.Leinval
     46 
     47 	/* place the func and it's arg onto the child's stack */
     48 	stmfd	r1!, {r0, r3}
     49 
     50 	/* syscall expects (flags, stack) */
     51 	mov	r0, r2
     52 
     53 	SYSTRAP(__clone)
     54 	bcs	PIC_SYM(CERROR, PLT)
     55 
     56 	/*
     57 	 * r1 and r0 are the same as from fork:
     58 	 * r1 == 0 in parent process, r1 == 1 in child process.
     59 	 * r0 == pid of child in parent, r0 == pid of parent in child.
     60 	 */
     61 	teq	r1, #0x00
     62 
     63 	/* if this is the parent then just return the pid */
     64 #ifdef __APCS_26__
     65 	moveqs	r15, r14
     66 #else
     67 	moveq	r15, r14
     68 #endif
     69 	/*
     70 	 * This is the child
     71 	 * load the function and arg off the stack
     72 	 */
     73 	ldmfd	sp!, {r1, r2}
     74 
     75 	/* setup return address */
     76 	add	lr, pc, #.Lreturnhere - . - 8
     77 
     78 	/* place arg in r0 */
     79 	mov	r0, r2
     80 
     81 	/* call the function */
     82 	mov	pc, r1
     83 
     84 .Lreturnhere:
     85 	/* call _exit with the returned value */
     86 	b	_C_LABEL(_exit)
     87 
     88 	/* NOTREACHED */
     89 
     90 	/* error handler if func or stack is NULL */
     91 .Leinval:
     92 	mov	R0, #EINVAL
     93 	b	PIC_SYM(CERROR, PLT)
     94