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
|
/* Copyright (C) 1996, 1997 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ralf Baechle <ralf@gnu.ai.mit.edu>, 1996.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
/* 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 <sys/asm.h>
#include <asm/unistd.h>
#include <sysdep.h>
#define _ERRNO_H 1
#include <bits/errno.h>
/* int clone(int (*fn)(), void *child_stack, int flags, int nargs, ...) */
#define FRAMESZ 4*SZREG
#if _MIPS_SIM == _MIPS_SIM_ABI32
#define MAX_REG_ARGS 4
#else
#define MAX_REG_ARGS 6
#endif
.text
NESTED(__clone,4*SZREG,sp)
#ifdef PIC
.set noreorder
.cpload $25
.set reorder
.cprestore 16
#endif
PTR_SUBIU sp,FRAMESZ
#ifdef PROF
.set noat
move $1,ra
jal _mcount
.set at
#endif
/* Sanity check arguments. */
li v0,EINVAL
beqz a0,error /* no NULL function pointers */
beqz a1,error /* no NULL stack pointers */
bltz a3,error /* no negative argument counts */
/* Allocate space on the new stack and copy args over */
move t0,a3 # save nargs for __thread_start
PTR_SLL t1,a3,PTR_SCALESHIFT
PTR_ADDU t1,a3,sp
1: REG_L t2,-SZREG(t1)
PTR_SUBIU t1,SZREG
REG_S t2,-SZREG(a1)
PTR_SUBIU a3,1
PTR_SUBIU a1,SZREG
bnez a3,1b
/* Do the system call */
move t9,a0 # get fn ptr out of the way
move a0,a2
li v0,__NR_clone
syscall
bnez a3,error
beqz v0,__thread_start
/* Successful return from the parent */
PTR_ADDIU sp,FRAMESZ
ret
/* Something bad happened -- no child created */
error:
PTR_ADDIU sp,FRAMESZ
#ifdef PIC
la t9,__syscall_error
jr t9
#else
j __syscall_error
#endif
END(__clone)
/* Load up the arguments to the function. Put this block of code in
its own function so that we can terminate the stack trace with our
debug info.
At this point we have t0=nargs, t9=fn, sp=&arg[0]. */
NESTED(__thread_start,32,sp)
/* Stackframe has been created on entry of clone() */
/* Calculate address of jump into argument loading code */
li t1,MAX_REG_ARGS
slt t0,t1,t2 /* max MAX_REG_ARGS args in registers */
MOVN (t2,t1,t0)
la v0,arg0
PTR_SLL t1,t0,PTR_SCALESHIFT
PTR_SUBU v0,t1
jr v0
/* Load the integer register arguments */
REG_L a0,SZREG(sp)
arg0:
/* Call the user's function */
jalr t9
/* Call _exit rather than doing it inline for breakpoint purposes */
move a0,v0
jal _exit
END(__thread_start)
weak_alias(__clone, clone)
|
