xref: /netbsd-src/lib/libc/arch/arm/sys/__clone.S (revision 45433ea2c30b2014f6657db155fbd2661d0085ce)
1/* $NetBSD: __clone.S,v 1.14 2021/06/30 21:20:30 skrll 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 "SYS.h"
30#include <sys/errno.h>
31
32#ifdef WEAK_ALIAS
33WEAK_ALIAS(clone, __clone)
34#endif
35
36/*
37 * int __clone(int (*fn)(void *), void *stack, int flags, void *arg);
38 */
39ENTRY(__clone)
40
41	/* test stack and function are not null */
42#if defined(__thumb__) && defined(_ARM_ARCH_T2)
43	cbz	r0, .Leinval
44	cbz	r1, .Leinval
45#elif !defined(__thumb__)
46	cmp	r0, #0x00
47	cmpne	r1, #0x00
48	beq	.Leinval
49#else
50	cmp	r0, #0x00
51	beq	.Leinval
52	cmp	r1, #0x00
53	beq	.Leinval
54#endif
55
56	/* place the func and its arg onto the child's stack */
57#if !defined(__thumb__) || defined(_ARM_ARCH_T2)
58	stmfd	r1!, {r0, r3}
59#else
60	subs	r1, r1, #8
61	stmia	r1!, {r0, r3}
62#endif
63
64	/* syscall expects (flags, stack) */
65	mov	r0, r2
66
67	SYSTRAP(__clone)
68	_INVOKE_CERROR()
69
70	/*
71	 * r1 and r0 are the same as from fork:
72	 * r1 == 0 in parent process, r1 == 1 in child process.
73	 * r0 == pid of child in parent, r0 == pid of parent in child.
74	 */
75	/* if this is the parent then just return the pid */
76#if defined(__thumb__)
77#if defined(_ARM_ARCH_T2)
78	cbz	r1, 1f
79#else
80	cmp	r1, #0x00
81	bne	1f
82#endif
83	RET
841:
85#else
86	cmp	r1, #0x00
87	RETc(eq)
88#endif
89
90	/*
91	 * This is the child
92	 * load the function and arg off the stack
93	 */
94	pop	{r1, r2}
95
96	/* place arg in r0 */
97	mov	r0, r2
98
99	/* call the function */
100#ifdef _ARM_ARCH_5T
101	blx	r1
102#else
103	/* setup return address */
104	mov	lr, pc
105	RETr(r1)
106#endif
107	/* call _exit with the returned value */
108	bl	PLT_SYM(_C_LABEL(_exit))
109
110	/* NOTREACHED */
111
112	/* error handler if func or stack is NULL */
113	.align	0
114.Leinval:
115	movs	r0, #EINVAL
116#if !defined(__thumb__) || defined(_ARM_ARCH_T2)
117	b	CERROR
118#else
119.Lcerror:
120	push	{r3, lr}
121	bl	CERROR
122	pop	{r3, pc}
123#endif
124END(__clone)
125