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

/*
 * Copyright (c) 1999-2010 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) 1992 NeXT Computer, Inc.  All rights reserved.
 *
 *	File:	libc/ppc/sys/fork.s
 *
 * HISTORY
 * 18-Nov-92  Ben Fathi (benf@next.com)
 *	Created from M88K sources
 *
 * 11-Jan-92  Peter King (king@next.com)
 *	Created from M68K sources
 */
 
/*
 * All of the asm stubs in this file have been adjusted so the pre/post
 * fork handlers and dyld fixup are done in C inside Libc. As such, Libc
 * expects the __fork asm to fix up the return code to be -1, 0 or pid
 * and errno if needed.
 */

#include "SYS.h"

#if defined(__i386__)

LEAF(___fork, 0)
	subl  $28, %esp   // Align the stack, with 16 bytes of extra padding that we'll need

	movl 	$ SYS_fork,%eax; 	// code for fork -> eax
	UNIX_SYSCALL_TRAP		// do the system call
	jnc	L1			// jump if CF==0

	CALL_EXTERN(tramp_cerror)
	movl	$-1,%eax
	addl	$28, %esp   // restore the stack
	ret
	
L1:
	orl	%edx,%edx	// CF=OF=0,  ZF set if zero result	
	jz	L2		// parent, since r1 == 0 in parent, 1 in child
	
	//child here...
	xorl	%eax,%eax	// zero eax
	REG_TO_EXTERN(%eax, __current_pid);
L2:
	addl	$28, %esp   // restore the stack
	// parent ends up here skipping child portion
	ret

#elif defined(__x86_64__)

LEAF(___fork, 0)
	subq  $24, %rsp   // Align the stack, plus room for local storage

	movl 	$ SYSCALL_CONSTRUCT_UNIX(SYS_fork),%eax; // code for fork -> rax
	UNIX_SYSCALL_TRAP		// do the system call
	jnc	L1			// jump if CF==0

	movq	%rax, %rdi
	CALL_EXTERN(_cerror)
	movq	$-1, %rax
	addq	$24, %rsp   // restore the stack
	ret
	
L1:
	orl	%edx,%edx	// CF=OF=0,  ZF set if zero result	
	jz	L2		// parent, since r1 == 0 in parent, 1 in child
	
	//child here...
	xorq	%rax, %rax
	PICIFY(__current_pid)
	movl	%eax,(%r11)
L2:
	// parent ends up here skipping child portion
	addq	$24, %rsp   // restore the stack
	ret

#elif defined(__arm__)
	
MI_ENTRY_POINT(___fork)
	stmfd	sp!, {r4, r7, lr}
	add	r7, sp, #4

	mov	r1, #1					// prime results
	mov	r12, #SYS_fork
	swi	#SWI_SYSCALL				// make the syscall
	bcs	Lbotch					// error?

	cmp	r1, #0					// parent (r1=0) or child(r1=1)
	beq	Lparent

	//child here...
	MI_GET_ADDRESS(r3, __current_pid)
	mov	r0, #0
	str	r0, [r3]		// clear cached pid in child
	ldmfd   sp!, {r4, r7, pc}

Lbotch:
	MI_CALL_EXTERNAL(_cerror)			// jump here on error
	mov	r0,#-1					// set the error
	// fall thru
Lparent:	
	ldmfd   sp!, {r4, r7, pc}			// pop and return

#elif defined(__arm64__)

#include <mach/arm64/asm.h>
	
MI_ENTRY_POINT(___fork)
	PUSH_FRAME
	// ARM moves a 1 in to r1 here, but I can't see why.
	mov		x16, #SYS_fork				// Syscall code
	svc		#SWI_SYSCALL				// Trap to kernel
	b.cs	Lbotch						// Carry bit indicates failure
	cbz		x1, Lparent					// x1 == 0 indicates that we are the parent

	// Child
	MI_GET_ADDRESS(x9, __current_pid)	// Get address of cached "current pid"
	mov		w0, #0	
	str		w0, [x9]					// Clear cached current pid				
	POP_FRAME							// And done
	ret

Lbotch:
	MI_CALL_EXTERNAL(_cerror)			// Handle error
	mov		w0, #-1						// Return value is -1
Lparent:
	POP_FRAME							// Return
	ret

#else
#error Unsupported architecture
#endif
Commit	Line	Data
2d21ac55	1	/*
6d2010ae	2	* Copyright (c) 1999-2010 Apple Inc. All rights reserved.
2d21ac55 A	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) 1992 NeXT Computer, Inc. All rights reserved.
	29	*
	30	* File: libc/ppc/sys/fork.s
	31	*
	32	* HISTORY
	33	* 18-Nov-92 Ben Fathi (benf@next.com)
	34	* Created from M88K sources
	35	*
	36	* 11-Jan-92 Peter King (king@next.com)
	37	* Created from M68K sources
	38	*/
6d2010ae A	39
	40	/*
	41	* All of the asm stubs in this file have been adjusted so the pre/post
	42	* fork handlers and dyld fixup are done in C inside Libc. As such, Libc
	43	* expects the __fork asm to fix up the return code to be -1, 0 or pid
	44	* and errno if needed.
2d21ac55	45	*/
2d21ac55	46
6d2010ae	47	#include "SYS.h"
2d21ac55	48
6d2010ae	49	#if defined(__i386__)
2d21ac55 A	50
	51	LEAF(___fork, 0)
	52	subl $28, %esp // Align the stack, with 16 bytes of extra padding that we'll need
2d21ac55 A	53
	54	movl $ SYS_fork,%eax; // code for fork -> eax
	55	UNIX_SYSCALL_TRAP // do the system call
	56	jnc L1 // jump if CF==0
	57
39236c6e	58	CALL_EXTERN(tramp_cerror)
2d21ac55 A	59	movl $-1,%eax
	60	addl $28, %esp // restore the stack
	61	ret
	62
	63	L1:
	64	orl %edx,%edx // CF=OF=0, ZF set if zero result
	65	jz L2 // parent, since r1 == 0 in parent, 1 in child
	66
	67	//child here...
2d21ac55	68	xorl %eax,%eax // zero eax
6d2010ae	69	REG_TO_EXTERN(%eax, __current_pid);
2d21ac55	70	L2:
2d21ac55	71	addl $28, %esp // restore the stack
6d2010ae A	72	// parent ends up here skipping child portion
6d2010ae A	73	ret
2d21ac55 A	74
	75	#elif defined(__x86_64__)
	76
	77	LEAF(___fork, 0)
	78	subq $24, %rsp // Align the stack, plus room for local storage
2d21ac55 A	79
	80	movl $ SYSCALL_CONSTRUCT_UNIX(SYS_fork),%eax; // code for fork -> rax
	81	UNIX_SYSCALL_TRAP // do the system call
	82	jnc L1 // jump if CF==0
	83
39236c6e A	84	movq %rax, %rdi
39236c6e A	85	CALL_EXTERN(_cerror)
2d21ac55 A	86	movq $-1, %rax
	87	addq $24, %rsp // restore the stack
	88	ret
	89
	90	L1:
	91	orl %edx,%edx // CF=OF=0, ZF set if zero result
	92	jz L2 // parent, since r1 == 0 in parent, 1 in child
	93
	94	//child here...
2d21ac55	95	xorq %rax, %rax
6d2010ae A	96	PICIFY(__current_pid)
6d2010ae A	97	movl %eax,(%r11)
2d21ac55	98	L2:
6d2010ae	99	// parent ends up here skipping child portion
2d21ac55	100	addq $24, %rsp // restore the stack
6d2010ae	101	ret
2d21ac55	102
5ba3f43e A	103	#elif defined(__arm__)
	104
	105	MI_ENTRY_POINT(___fork)
	106	stmfd sp!, {r4, r7, lr}
	107	add r7, sp, #4
	108
	109	mov r1, #1 // prime results
	110	mov r12, #SYS_fork
	111	swi #SWI_SYSCALL // make the syscall
	112	bcs Lbotch // error?
	113
	114	cmp r1, #0 // parent (r1=0) or child(r1=1)
	115	beq Lparent
	116
	117	//child here...
	118	MI_GET_ADDRESS(r3, __current_pid)
	119	mov r0, #0
	120	str r0, [r3] // clear cached pid in child
	121	ldmfd sp!, {r4, r7, pc}
	122
	123	Lbotch:
	124	MI_CALL_EXTERNAL(_cerror) // jump here on error
	125	mov r0,#-1 // set the error
	126	// fall thru
	127	Lparent:
	128	ldmfd sp!, {r4, r7, pc} // pop and return
	129
	130	#elif defined(__arm64__)
	131
	132	#include <mach/arm64/asm.h>
	133
	134	MI_ENTRY_POINT(___fork)
	135	PUSH_FRAME
	136	// ARM moves a 1 in to r1 here, but I can't see why.
	137	mov x16, #SYS_fork // Syscall code
	138	svc #SWI_SYSCALL // Trap to kernel
	139	b.cs Lbotch // Carry bit indicates failure
	140	cbz x1, Lparent // x1 == 0 indicates that we are the parent
	141
	142	// Child
	143	MI_GET_ADDRESS(x9, __current_pid) // Get address of cached "current pid"
	144	mov w0, #0
	145	str w0, [x9] // Clear cached current pid
	146	POP_FRAME // And done
	147	ret
	148
	149	Lbotch:
	150	MI_CALL_EXTERNAL(_cerror) // Handle error
	151	mov w0, #-1 // Return value is -1
	152	Lparent:
	153	POP_FRAME // Return
	154	ret
	155
2d21ac55 A	156	#else
	157	#error Unsupported architecture
	158	#endif