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
|
/* Wrapper around clone system call.
Copyright (C) 1997, 1998, 1999, 2000 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, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include "ppc_asm.h"
#define _ERRNO_H 1
#include <bits/errno.h>
#include <sys/syscall.h>
/* This is the only really unusual system call in PPC linux, but not
because of any weirdness in the system call itself; because of
all the freaky stuff we have to do to make the call useful. */
/* int [r3] clone(int (*fn)(void *arg) [r3], void *child_stack [r4],
int flags [r5], void *arg [r6]); */
#ifdef __NR_clone
.globl __clone
.type __clone,@function
.align 2
__clone:
/* Check for child_stack == NULL || fn == NULL. */
cmpwi cr0,r4,0
cmpwi cr1,r3,0
cror cr0*4+eq,cr1*4+eq,cr0*4+eq
beq- cr0,.Lbadargs
/* Set up stack frame for parent. */
stwu r1,-32(r1)
stmw r29,16(r1)
/* Set up stack frame for child. */
clrrwi r4,r4,4
li r0,0
stwu r0,-16(r4)
/* Save fn, args, stack across syscall. */
mr r29,r3 /* Function in r29. */
mr r30,r4 /* Stack pointer in r30. */
mr r31,r6 /* Argument in r31. */
/* 'flags' argument is first parameter to clone syscall. (The other
argument is the stack pointer, already in r4.) */
mr r3,r5
/* Do the call. */
li 0, __NR_clone
sc
/* Check for child process. */
cmpwi cr1,r3,0
crandc cr1*4+eq,cr1*4+eq,cr0*4+so
bne- cr1,.Lparent /* The '-' is to minimise the race. */
/* On at least mklinux DR3a5, clone() doesn't actually change
the stack pointer. I'm pretty sure this is a bug, because
it adds a race condition if a signal is sent to a thread
just after it is created (in the previous three instructions). */
mr r1,r30
/* Call procedure. */
mtctr r29
mr r3,r31
bctrl
/* Call _exit with result from procedure. */
b _exit_internal
.Lparent:
/* Parent. Restore registers & return. */
lmw r29,16(r1)
addi r1,r1,32
bnslr+
b __syscall_error
.Lbadargs:
li r3,EINVAL
b __syscall_error
.size __clone,.-__clone
.weak clone
clone=__clone
#endif
|
