summaryrefslogtreecommitdiff
path: root/sysdeps/unix/sysv/linux/sh/clone.S
blob: bcbe9e7650dd80724abe83e259f22ee161fc2315 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
/* Copyright (C) 1999-2013 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

/* clone() is even more special than fork() as it mucks with stacks
   and invokes a function in the right context after its all over.  */

#include <sysdep.h>
#define _ERRNO_H	1
#include <bits/errno.h>
#ifdef RESET_PID
#include <tcb-offsets.h>
#endif
/* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg,
	     pid_t *ptid, void *tls, pid_t *ctid); */

	.text
ENTRY(__clone)
	/* sanity check arguments.  */
	tst	r4, r4
	bt/s	0f
	 tst	r5, r5
	bf	1f
0:
	bra	.Lsyscall_error
	 mov	#-EINVAL,r0
1:
	/* insert the args onto the new stack */
	mov.l	r7, @-r5
	/* save the function pointer as the 0th element */
	mov.l	r4, @-r5

	/* do the system call */
	mov	r6, r4
	mov.l	@r15, r6
	mov.l	@(8,r15), r7
	mov.l	@(4,r15), r0
	mov	#+SYS_ify(clone), r3
	trapa	#0x15
	mov     r0, r1
	mov	#-12, r2
	shad	r2, r1
	not	r1, r1			// r1=0 means r0 = -1 to -4095
	tst	r1, r1			// i.e. error in linux
	bf	.Lclone_end
.Lsyscall_error:	
	SYSCALL_ERROR_HANDLER
.Lclone_end:
	tst	r0, r0
	bt	2f
.Lpseudo_end:
	rts
	 nop
2:
	/* terminate the stack frame */
	mov	#0, r14
#ifdef RESET_PID
	mov	r4, r0
	shlr16	r0
	tst	#1, r0			// CLONE_THREAD = (1 << 16)
	bf/s	4f
	 mov	r4, r0
	/* new pid */
	shlr8	r0
	tst	#1, r0			// CLONE_VM = (1 << 8)
	bf/s	3f
	 mov	#-1, r0
	mov	#+SYS_ify(getpid), r3
	trapa	#0x15
3:
	stc	gbr, r1
	mov.w	.Lpidoff, r2
	add	r1, r2
	mov.l	r0, @r2	
	mov.w	.Ltidoff, r2
	add	r1, r2
	mov.l	r0, @r2	
4:
#endif
	/* thread starts */
	mov.l	@r15, r1
	jsr	@r1
	 mov.l	@(4,r15), r4

	/* we are done, passing the return value through r0  */
	mov.l	.L3, r1
#ifdef SHARED
	mov.l	r12, @-r15
	sts.l	pr, @-r15
	mov	r0, r4
	mova	.LG, r0
	mov.l	.LG, r12
	add	r0, r12
	mova	.L3, r0
	add	r0, r1
	jsr	@r1
	 nop
	lds.l	@r15+, pr
	rts
	 mov.l	@r15+, r12
#else
	jmp	@r1
	 mov	r0, r4
#endif
	.align	2
.LG:
	.long	_GLOBAL_OFFSET_TABLE_
.L3:
	.long	PLTJMP(C_SYMBOL_NAME(_exit))
#ifdef RESET_PID
.Lpidoff:
	.word	PID - TLS_PRE_TCB_SIZE
.Ltidoff:
	.word	TID - TLS_PRE_TCB_SIZE
#endif
PSEUDO_END (__clone)

weak_alias (__clone, clone)