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
|
! Copyright (C) 2013 Imagination Technologies Ltd.
! Licensed under the LGPL v2.1 or later, see the file COPYING.LIB in this tarball.
! 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 <asm/errno.h>
#include <asm/unistd.h>
#define CLONE_VM 0x00000100
#define CLONE_THREAD 0x00010000
#ifdef __PIC__
#define __CLONE_METAG_LOAD_TP ___metag_load_tp@PLT
#else
#define __CLONE_METAG_LOAD_TP ___metag_load_tp
#endif
/* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg,
pid_t *ptid, struct user_desc *tls, pid_t *ctid); */
.text
.global __clone
.type __clone,function
__clone:
! sanity check args
MOV D0Re0, #-EINVAL
CMP D1Ar1, #0
BEQ ___error
CMP D0Ar2, #0
BEQ ___error
! save function pointer
MOV D0FrT, D1Ar1
! do the system call
MOV D1Ar1, D1Ar3
MOV D1Ar3, D1Ar5
MOV D1Ar5, D0Ar6
MOV D0Ar6, D0Ar4
GETD D0Ar4, [A0StP+#-4]
! new sp is already in D0Ar2
MOV D1Re0, #__NR_clone
SWITCH #0x440001
CMP D0Re0,#0
! Error on -1
BLT ___error
! If non-zero we are the parent
MOVNE PC, D1RtP
! BRKPNT
! We are the child
#ifdef RESET_PID
SETL [A0StP++], D0FrT, D1RtP
MOVT D0FrT, #HI(CLONE_THREAD)
ADD D0FrT, D0FrT, #LO(CLONE_THREAD)
ANDS D0FrT, D0FrT, D1Ar1
BNZ 3f
MOVT D0FrT, #HI(CLONE_VM)
ADD D0FrT, D0FrT, #LO(CLONE_VM)
ANDS D0FrT, D0FrT, D1Ar1
BZ 1f
MOV D1Ar1, #-1
BA 2f
1: MOV D1Re0, #__NR_getpid
SWITCH #0x440001
MOV D1Ar1, D0Re0
2: CALLR D1RtP, __CLONE_METAG_LOAD_TP
SUB D0Re0, D0Re0, #TLS_PRE_TCB_SIZE
SETD [D0Re0 + #PID], D1Ar1
SETD [D0Re0 + #TID], D1Ar1
3: GETL D0FrT, D1RtP, [--A0StP]
#endif
! Rearrange the function arg and call address from registers
MOV D0Ar2, D0FrT
MOV D1Ar1, D0Ar6
MOV D1RtP, PC
ADD D1RtP, D1RtP, #8
MOV PC, D0Ar2
! and we are done, passing the return value D0Re0 through D1Ar1
MOV D1Ar1, D0Re0
#ifdef __PIC__
B _exit@PLT
#else
B _exit
#endif
___error:
MOV D1Ar1, D0Re0
#ifdef __PIC__
B ___syscall_error@PLT
#else
B ___syscall_error
#endif
.size __clone, .-__clone
.weak _clone
_clone = __clone
|
