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
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
|
/* Copyright (C) 2003-2013 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, see
<http://www.gnu.org/licenses/>. */
#include <unwindbuf.h>
#include <sysdep.h>
#include <kernel-features.h>
#include <lowlevellock.h>
#include "lowlevel-atomic.h"
.comm __fork_generation, 4, 4
.text
.globl __pthread_once
.type __pthread_once,@function
.align 5
cfi_startproc
__pthread_once:
mov.l @r4, r0
tst #2, r0
bt 1f
rts
mov #0, r0
1:
mov.l r12, @-r15
cfi_adjust_cfa_offset (4)
cfi_rel_offset (r12, 0)
mov.l r9, @-r15
cfi_adjust_cfa_offset (4)
cfi_rel_offset (r9, 0)
mov.l r8, @-r15
cfi_adjust_cfa_offset (4)
cfi_rel_offset (r8, 0)
sts.l pr, @-r15
cfi_adjust_cfa_offset (4)
cfi_rel_offset (pr, 0)
mov r5, r8
mov r4, r9
/* Not yet initialized or initialization in progress.
Get the fork generation counter now. */
6:
mov.l @r4, r1
mova .Lgot, r0
mov.l .Lgot, r12
add r0, r12
5:
mov r1, r0
tst #2, r0
bf 4f
and #3, r0
mov.l .Lfgen, r2
#ifdef PIC
add r12, r2
#endif
mov.l @r2, r3
or r3, r0
or #1, r0
mov r0, r3
mov r1, r5
CMPXCHG (r5, @r4, r3, r2)
bf 5b
/* Check whether another thread already runs the initializer. */
mov r2, r0
tst #1, r0
bt 3f /* No -> do it. */
/* Check whether the initializer execution was interrupted
by a fork. */
xor r3, r0
mov #-4, r1 /* -4 = 0xfffffffc */
tst r1, r0
bf 3f /* Different for generation -> run initializer. */
/* Somebody else got here first. Wait. */
#ifdef __ASSUME_PRIVATE_FUTEX
mov #(FUTEX_PRIVATE_FLAG|FUTEX_WAIT), r5
extu.b r5, r5
#else
stc gbr, r1
mov.w .Lpfoff, r2
add r2, r1
mov.l @r1, r5
# if FUTEX_WAIT != 0
mov #FUTEX_WAIT, r0
or r0, r5
# endif
#endif
mov r3, r6
mov #0, r7
mov #SYS_futex, r3
extu.b r3, r3
trapa #0x14
SYSCALL_INST_PAD
bra 6b
nop
.align 2
.Lgot:
.long _GLOBAL_OFFSET_TABLE_
#ifdef PIC
.Lfgen:
.long __fork_generation@GOTOFF
#else
.Lfgen:
.long __fork_generation
#endif
3:
/* Call the initializer function after setting up the
cancellation handler. Note that it is not possible here
to use the unwind-based cleanup handling. This would require
that the user-provided function and all the code it calls
is compiled with exceptions. Unfortunately this cannot be
guaranteed. */
add #-UNWINDBUFSIZE, r15
cfi_adjust_cfa_offset (UNWINDBUFSIZE)
mov.l .Lsigsetjmp, r1
mov #UWJMPBUF, r4
add r15, r4
bsrf r1
mov #0, r5
.Lsigsetjmp0:
tst r0, r0
bf 7f
mov.l .Lcpush, r1
bsrf r1
mov r15, r4
.Lcpush0:
/* Call the user-provided initialization function. */
jsr @r8
nop
/* Pop the cleanup handler. */
mov.l .Lcpop, r1
bsrf r1
mov r15, r4
.Lcpop0:
add #UNWINDBUFSIZE, r15
cfi_adjust_cfa_offset (-UNWINDBUFSIZE)
/* Sucessful run of the initializer. Signal that we are done. */
INC (@r9, r2)
/* Wake up all other threads. */
mov r9, r4
#ifdef __ASSUME_PRIVATE_FUTEX
mov #(FUTEX_PRIVATE_FLAG|FUTEX_WAKE), r5
extu.b r5, r5
#else
stc gbr, r1
mov.w .Lpfoff, r2
add r2, r1
mov.l @r1, r5
mov #FUTEX_WAKE, r0
or r0, r5
#endif
mov #-1, r6
shlr r6 /* r6 = 0x7fffffff */
mov #0, r7
mov #SYS_futex, r3
extu.b r3, r3
trapa #0x14
SYSCALL_INST_PAD
4:
lds.l @r15+, pr
cfi_adjust_cfa_offset (-4)
cfi_restore (pr)
mov.l @r15+, r8
cfi_adjust_cfa_offset (-4)
cfi_restore (r8)
mov.l @r15+, r9
cfi_adjust_cfa_offset (-4)
cfi_restore (r9)
mov.l @r15+, r12
cfi_adjust_cfa_offset (-4)
cfi_restore (r12)
rts
mov #0, r0
7:
/* __sigsetjmp returned for the second time. */
cfi_adjust_cfa_offset (UNWINDBUFSIZE+16)
cfi_offset (r12, -4)
cfi_offset (r9, -8)
cfi_offset (r8, -12)
cfi_offset (pr, -16)
mov #0, r7
mov.l r7, @r9
mov r9, r4
#ifdef __ASSUME_PRIVATE_FUTEX
mov #(FUTEX_PRIVATE_FLAG|FUTEX_WAKE), r5
#else
stc gbr, r1
mov.w .Lpfoff, r2
add r2, r1
mov.l @r1, r5
mov #FUTEX_WAKE, r0
or r0, r5
#endif
extu.b r5, r5
mov #-1, r6
shlr r6 /* r6 = 0x7fffffff */
mov #SYS_futex, r3
extu.b r3, r3
trapa #0x14
SYSCALL_INST_PAD
mov.l .Lunext, r1
bsrf r1
mov r15, r4
.Lunext0:
/* NOTREACHED */
sleep
cfi_endproc
#ifndef __ASSUME_PRIVATE_FUTEX
.Lpfoff:
.word PRIVATE_FUTEX - TLS_PRE_TCB_SIZE
#endif
.align 2
.Lsigsetjmp:
.long __sigsetjmp@PLT-(.Lsigsetjmp0-.)
.Lcpush:
.long HIDDEN_JUMPTARGET(__pthread_register_cancel)-.Lcpush0
.Lcpop:
.long HIDDEN_JUMPTARGET(__pthread_unregister_cancel)-.Lcpop0
.Lunext:
.long HIDDEN_JUMPTARGET(__pthread_unwind_next)-.Lunext0
.size __pthread_once,.-__pthread_once
hidden_def (__pthread_once)
strong_alias (__pthread_once, pthread_once)
|
