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
132
133
134
135
136
|
/* Copyright (C) 1996-2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Richard Henderson <rth@tamu.edu>, 1996.
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>
#define CLONE_VM 0x00000100
/* int clone(int (*fn)(void *arg), void *child_stack, int flags,
void *arg, pid_t *ptid, void *tls, pid_t *ctid);
Note that everything past ARG is technically optional, based
on FLAGS, and that CTID is arg 7, and thus is on the stack.
However, since a load from top-of-stack better be legal always,
we don't bother checking FLAGS. */
.text
.align 4
.globl __clone
.ent __clone
.usepv __clone, USEPV_PROF
cfi_startproc
__clone:
#ifdef PROF
ldgp gp,0(pv)
lda AT, _mcount
jsr AT, (AT), _mcount
#endif
/* Sanity check arguments. */
ldiq v0, EINVAL
beq a0, SYSCALL_ERROR_LABEL /* no NULL function pointers */
beq a1, SYSCALL_ERROR_LABEL /* no NULL stack pointers */
/* Save the fn ptr and arg on the new stack. */
subq a1, 32, a1
stq a0, 0(a1)
stq a3, 8(a1)
stq a2, 16(a1)
/* The syscall is of the form clone(flags, usp, ptid, ctid, tls).
Shift the flags, ptid, ctid, tls arguments into place; the
child_stack argument is already correct. */
mov a2, a0
mov a4, a2
ldq a3, 0(sp)
mov a5, a4
/* Do the system call. */
ldiq v0, __NR_clone
call_pal PAL_callsys
bne a3, SYSCALL_ERROR_LABEL
beq v0, thread_start
/* Successful return from the parent. */
ret
PSEUDO_END(__clone)
cfi_endproc
/* 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. */
.align 4
.ent thread_start
cfi_startproc
thread_start:
mov 0, fp
cfi_def_cfa_register(fp)
cfi_undefined(ra)
/* Check and see if we need to reset the PID. */
ldq t0, 16(sp)
lda t1, CLONE_VM
and t0, t1, t2
beq t2, 2f
1:
/* Load up the arguments. */
ldq pv, 0(sp)
ldq a0, 8(sp)
addq sp, 32, sp
/* Call the user's function. */
jsr ra, (pv)
ldgp gp, 0(ra)
/* Call _exit rather than doing it inline for breakpoint purposes. */
mov v0, a0
#ifdef PIC
bsr ra, HIDDEN_JUMPTARGET(_exit) !samegp
#else
jsr ra, HIDDEN_JUMPTARGET(_exit)
#endif
/* Die horribly. */
.align 4
halt
.align 4
2:
rduniq
mov v0, s0
lda v0, __NR_getxpid
callsys
3:
stl v0, PID_OFFSET(s0)
stl v0, TID_OFFSET(s0)
br 1b
cfi_endproc
.end thread_start
libc_hidden_def (__clone)
weak_alias (__clone, clone)
|
