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
|
/* clone() implementation for Nios II.
Copyright (C) 2008-2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Andrew Jenner <andrew@codesourcery.com>, 2008.
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>
#include <tcb-offsets.h>
#define CLONE_VM 0x00000100
#define CLONE_THREAD 0x00010000
/* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg,
void *parent_tidptr, void *tls, void *child_tidptr) */
.text
ENTRY(__clone)
/* Sanity check arguments. */
movi r2, EINVAL
/* No NULL function pointers. */
beq r4, zero, SYSCALL_ERROR_LABEL
/* No NULL stack pointers. */
beq r5, zero, SYSCALL_ERROR_LABEL
subi r5, r5, 8 /* Reserve argument save space. */
stw r4, 4(r5) /* Save function pointer. */
stw r7, 0(r5) /* Save argument pointer. */
/* Load arguments. */
mov r4, r6
ldw r6, 0(sp)
ldw r7, 8(sp)
ldw r8, 4(sp)
/* Do the system call. */
movi r2, SYS_ify (clone)
/* End FDE now, because in the child the unwind info will be
wrong. */
cfi_endproc
trap
/* Check for errors. */
bne r7, zero, SYSCALL_ERROR_LABEL
/* See if we're on the newly created thread. */
beq r2, zero, thread_start
/* Successful return from the parent */
ret
thread_start:
cfi_startproc
cfi_undefined (ra)
/* We expect the argument registers to be preserved across system
calls and across task cloning, so flags should be in r4 here. */
andhi r2, r4, %hi(CLONE_THREAD)
bne r2, zero, 2f
andi r3, r4, CLONE_VM
movi r2, -1
bne r3, zero, 3f
DO_CALL (getpid, 0)
3:
stw r2, PID_OFFSET(r23)
stw r2, TID_OFFSET(r23)
2:
ldw r5, 4(sp) /* Function pointer. */
ldw r4, 0(sp) /* Argument pointer. */
addi sp, sp, 8
/* Call the user's function. */
callr r5
/* _exit with the result. */
mov r4, r2
#ifdef PIC
nextpc r22
1: movhi r8, %hiadj(_gp_got - 1b)
addi r8, r8, %lo(_gp_got - 1b)
add r22, r22, r8
ldw r8, %call(HIDDEN_JUMPTARGET(_exit))(r22)
jmp r8
#else
jmpi _exit
#endif
cfi_endproc
cfi_startproc
PSEUDO_END (__clone)
libc_hidden_def (__clone)
weak_alias (__clone, clone)
|
