[apple/xnu.git] / libsyscall / custom / __vfork.s

/*
 * Copyright (c) 1999-2007 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/* Copyright (c) 1998 Apple Computer, Inc.  All rights reserved.
 *
 *	File:	libc/ppc/sys/vfork.s
 *
 * HISTORY
 * 23-Jun-1998	Umesh Vaishampayan (umeshv@apple.com)
 *	Created from fork.s
 *
 */

#include "SYS.h"

#if defined(__i386__)

#if defined(__DYNAMIC__)
#define GET_CURRENT_PID	PICIFY(__current_pid)

        NON_LAZY_STUB(__current_pid)
#define __current_pid	(%edx)
#else
#define GET_CURRENT_PID
#endif

/*
 * If __current_pid >= 0, we want to put a -1 in there
 * otherwise we just decrement it
 */

LEAF(___vfork, 0)
	GET_CURRENT_PID
	movl		__current_pid, %eax
0:
	xorl		%ecx, %ecx
	testl		%eax, %eax
	cmovs		%eax, %ecx
	decl		%ecx
	lock
	cmpxchgl	%ecx, __current_pid
	jne		0b
	popl		%ecx
	movl		$(SYS_vfork), %eax	// code for vfork -> eax
	UNIX_SYSCALL_TRAP			// do the system call
	jnb		L1                     	// jump if CF==0
	GET_CURRENT_PID
	lock
	incl		__current_pid
	pushl		%ecx
	BRANCH_EXTERN(tramp_cerror)

L1:
	testl		%edx, %edx		// CF=OF=0,  ZF set if zero result
	jz		L2			// parent, since r1 == 0 in parent, 1 in child
	xorl		%eax, %eax		// zero eax
	jmp		*%ecx

L2:
	GET_CURRENT_PID
	lock
	incl		__current_pid
	jmp		*%ecx

#elif defined(__x86_64__)

/*
 * If __current_pid >= 0, we want to put a -1 in there
 * otherwise we just decrement it
 */

LEAF(___vfork, 0)
	movq		__current_pid@GOTPCREL(%rip), %rax
	movl		(%rax), %eax
0:
	xorl		%ecx, %ecx
	testl		%eax, %eax
	cmovs		%eax, %ecx
	subl		$1, %ecx
	movq		__current_pid@GOTPCREL(%rip), %rdx
	lock
	cmpxchgl	%ecx, (%rdx)
	jne		0b
	popq		%rdi			// return address in %rdi
	movq		$ SYSCALL_CONSTRUCT_UNIX(SYS_vfork), %rax	// code for vfork -> rax
	UNIX_SYSCALL_TRAP			// do the system call
	jnb		L1			// jump if CF==0
	pushq		%rdi			// put return address back on stack for cerror
	movq		__current_pid@GOTPCREL(%rip), %rcx
	lock
	addl		$1, (%rcx)
	movq		%rax, %rdi
	BRANCH_EXTERN(_cerror)

L1:
	testl		%edx, %edx		// CF=OF=0,  ZF set if zero result
	jz		L2			// parent, since r1 == 0 in parent, 1 in child
	xorq		%rax, %rax		// zero rax
	jmp		*%rdi

L2:
	movq		__current_pid@GOTPCREL(%rip), %rdx
	lock
	addl		$1, (%rdx)
	jmp		*%rdi

#else
#error Unsupported architecture
#endif
Commit	Line	Data
2d21ac55 A	1	/*
	2	* Copyright (c) 1999-2007 Apple Inc. All rights reserved.
	3	*
	4	* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
	5	*
	6	* This file contains Original Code and/or Modifications of Original Code
	7	* as defined in and that are subject to the Apple Public Source License
	8	* Version 2.0 (the 'License'). You may not use this file except in
	9	* compliance with the License. The rights granted to you under the License
	10	* may not be used to create, or enable the creation or redistribution of,
	11	* unlawful or unlicensed copies of an Apple operating system, or to
	12	* circumvent, violate, or enable the circumvention or violation of, any
	13	* terms of an Apple operating system software license agreement.
	14	*
	15	* Please obtain a copy of the License at
	16	* http://www.opensource.apple.com/apsl/ and read it before using this file.
	17	*
	18	* The Original Code and all software distributed under the License are
	19	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
	20	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
	21	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
	22	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	23	* Please see the License for the specific language governing rights and
	24	* limitations under the License.
	25	*
	26	* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
	27	*/
	28	/* Copyright (c) 1998 Apple Computer, Inc. All rights reserved.
	29	*
	30	* File: libc/ppc/sys/vfork.s
	31	*
	32	* HISTORY
	33	* 23-Jun-1998 Umesh Vaishampayan (umeshv@apple.com)
	34	* Created from fork.s
	35	*
	36	*/
	37
	38	#include "SYS.h"
	39
6d2010ae	40	#if defined(__i386__)
2d21ac55 A	41
	42	#if defined(__DYNAMIC__)
	43	#define GET_CURRENT_PID PICIFY(__current_pid)
	44
	45	NON_LAZY_STUB(__current_pid)
	46	#define __current_pid (%edx)
	47	#else
	48	#define GET_CURRENT_PID
	49	#endif
	50
	51	/*
	52	* If __current_pid >= 0, we want to put a -1 in there
	53	* otherwise we just decrement it
	54	*/
	55
	56	LEAF(___vfork, 0)
	57	GET_CURRENT_PID
	58	movl __current_pid, %eax
	59	0:
	60	xorl %ecx, %ecx
	61	testl %eax, %eax
	62	cmovs %eax, %ecx
	63	decl %ecx
	64	lock
	65	cmpxchgl %ecx, __current_pid
	66	jne 0b
	67	popl %ecx
	68	movl $(SYS_vfork), %eax // code for vfork -> eax
	69	UNIX_SYSCALL_TRAP // do the system call
	70	jnb L1 // jump if CF==0
	71	GET_CURRENT_PID
	72	lock
	73	incl __current_pid
	74	pushl %ecx
39236c6e	75	BRANCH_EXTERN(tramp_cerror)
2d21ac55 A	76
	77	L1:
	78	testl %edx, %edx // CF=OF=0, ZF set if zero result
	79	jz L2 // parent, since r1 == 0 in parent, 1 in child
	80	xorl %eax, %eax // zero eax
	81	jmp *%ecx
	82
	83	L2:
	84	GET_CURRENT_PID
	85	lock
	86	incl __current_pid
	87	jmp *%ecx
	88
	89	#elif defined(__x86_64__)
	90
	91	/*
	92	* If __current_pid >= 0, we want to put a -1 in there
	93	* otherwise we just decrement it
	94	*/
	95
	96	LEAF(___vfork, 0)
	97	movq __current_pid@GOTPCREL(%rip), %rax
	98	movl (%rax), %eax
	99	0:
	100	xorl %ecx, %ecx
	101	testl %eax, %eax
	102	cmovs %eax, %ecx
	103	subl $1, %ecx
	104	movq __current_pid@GOTPCREL(%rip), %rdx
	105	lock
	106	cmpxchgl %ecx, (%rdx)
	107	jne 0b
	108	popq %rdi // return address in %rdi
	109	movq $ SYSCALL_CONSTRUCT_UNIX(SYS_vfork), %rax // code for vfork -> rax
	110	UNIX_SYSCALL_TRAP // do the system call
39236c6e	111	jnb L1 // jump if CF==0
b0d623f7	112	pushq %rdi // put return address back on stack for cerror
2d21ac55 A	113	movq __current_pid@GOTPCREL(%rip), %rcx
2d21ac55 A	114	lock
39037602	115	addl $1, (%rcx)
39236c6e A	116	movq %rax, %rdi
39236c6e A	117	BRANCH_EXTERN(_cerror)
2d21ac55 A	118
	119	L1:
	120	testl %edx, %edx // CF=OF=0, ZF set if zero result
	121	jz L2 // parent, since r1 == 0 in parent, 1 in child
	122	xorq %rax, %rax // zero rax
	123	jmp *%rdi
	124
	125	L2:
	126	movq __current_pid@GOTPCREL(%rip), %rdx
	127	lock
39037602	128	addl $1, (%rdx)
2d21ac55 A	129	jmp *%rdi
2d21ac55 A	130
2d21ac55 A	131	#else
	132	#error Unsupported architecture
	133	#endif