about summary refs log tree commit diff
path: root/sysdeps/unix/sysv/linux/i386/lowlevellock.S
blob: feda390eeb1cf3c363efbb4bc3b36cfcf8206c28 (plain) (blame)
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
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
/* Copyright (C) 2002-2018 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.

   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 <sysdep.h>
#include <pthread-errnos.h>
#include <kernel-features.h>
#include <lowlevellock.h>

#include <stap-probe.h>

	.text

#define LOAD_PRIVATE_FUTEX_WAIT(reg) \
	movl	$(FUTEX_WAIT | FUTEX_PRIVATE_FLAG), reg
#define LOAD_PRIVATE_FUTEX_WAKE(reg) \
	movl	$(FUTEX_WAKE | FUTEX_PRIVATE_FLAG), reg
#define LOAD_FUTEX_WAIT(reg) \
	xorl	$(FUTEX_WAIT | FUTEX_PRIVATE_FLAG), reg
#define LOAD_FUTEX_WAIT_ABS(reg) \
	xorl	$(FUTEX_WAIT_BITSET | FUTEX_PRIVATE_FLAG | FUTEX_CLOCK_REALTIME), reg
#define LOAD_FUTEX_WAKE(reg) \
	xorl	$(FUTEX_WAKE | FUTEX_PRIVATE_FLAG), reg

	.globl	__lll_lock_wait_private
	.type	__lll_lock_wait_private,@function
	.hidden	__lll_lock_wait_private
	.align	16
__lll_lock_wait_private:
	cfi_startproc
	pushl	%edx
	cfi_adjust_cfa_offset(4)
	pushl	%ebx
	cfi_adjust_cfa_offset(4)
	pushl	%esi
	cfi_adjust_cfa_offset(4)
	cfi_offset(%edx, -8)
	cfi_offset(%ebx, -12)
	cfi_offset(%esi, -16)

	movl	$2, %edx
	movl	%ecx, %ebx
	xorl	%esi, %esi	/* No timeout.  */
	LOAD_PRIVATE_FUTEX_WAIT (%ecx)

	cmpl	%edx, %eax	/* NB:	 %edx == 2 */
	jne 2f

1:	LIBC_PROBE (lll_lock_wait_private, 1, %ebx)
	movl	$SYS_futex, %eax
	ENTER_KERNEL

2:	movl	%edx, %eax
	xchgl	%eax, (%ebx)	/* NB:	 lock is implied */

	testl	%eax, %eax
	jnz	1b

	popl	%esi
	cfi_adjust_cfa_offset(-4)
	cfi_restore(%esi)
	popl	%ebx
	cfi_adjust_cfa_offset(-4)
	cfi_restore(%ebx)
	popl	%edx
	cfi_adjust_cfa_offset(-4)
	cfi_restore(%edx)
	ret
	cfi_endproc
	.size	__lll_lock_wait_private,.-__lll_lock_wait_private

#if !IS_IN (libc)
	.globl	__lll_lock_wait
	.type	__lll_lock_wait,@function
	.hidden	__lll_lock_wait
	.align	16
__lll_lock_wait:
	cfi_startproc
	pushl	%edx
	cfi_adjust_cfa_offset(4)
	pushl	%ebx
	cfi_adjust_cfa_offset(4)
	pushl	%esi
	cfi_adjust_cfa_offset(4)
	cfi_offset(%edx, -8)
	cfi_offset(%ebx, -12)
	cfi_offset(%esi, -16)

	movl	%edx, %ebx
	movl	$2, %edx
	xorl	%esi, %esi	/* No timeout.  */
	LOAD_FUTEX_WAIT (%ecx)

	cmpl	%edx, %eax	/* NB:	 %edx == 2 */
	jne 2f

1:	movl	$SYS_futex, %eax
	ENTER_KERNEL

2:	movl	%edx, %eax
	xchgl	%eax, (%ebx)	/* NB:	 lock is implied */

	testl	%eax, %eax
	jnz	1b

	popl	%esi
	cfi_adjust_cfa_offset(-4)
	cfi_restore(%esi)
	popl	%ebx
	cfi_adjust_cfa_offset(-4)
	cfi_restore(%ebx)
	popl	%edx
	cfi_adjust_cfa_offset(-4)
	cfi_restore(%edx)
	ret
	cfi_endproc
	.size	__lll_lock_wait,.-__lll_lock_wait

	/*      %ecx: futex
		%esi: flags
		%edx: timeout
		%eax: futex value
	*/
	.globl	__lll_timedlock_wait
	.type	__lll_timedlock_wait,@function
	.hidden	__lll_timedlock_wait
	.align	16
__lll_timedlock_wait:
	cfi_startproc
	pushl	%ebp
	cfi_adjust_cfa_offset(4)
	cfi_rel_offset(%ebp, 0)
	pushl	%ebx
	cfi_adjust_cfa_offset(4)
	cfi_rel_offset(%ebx, 0)

# ifndef __ASSUME_FUTEX_CLOCK_REALTIME
#  ifdef PIC
	LOAD_PIC_REG (bx)
	cmpl	$0, __have_futex_clock_realtime@GOTOFF(%ebx)
#  else
	cmpl	$0, __have_futex_clock_realtime
#  endif
	je	.Lreltmo
# endif

	cmpl	$0, (%edx)
	js	8f

	movl	%ecx, %ebx
	movl	%esi, %ecx
	movl	%edx, %esi
	movl	$0xffffffff, %ebp
	LOAD_FUTEX_WAIT_ABS (%ecx)

	movl	$2, %edx
	cmpl	%edx, %eax
	jne	2f

1:	movl	$SYS_futex, %eax
	movl	$2, %edx
	ENTER_KERNEL

2:	xchgl	%edx, (%ebx)	/* NB:   lock is implied */

	testl	%edx, %edx
	jz	3f

	cmpl	$-ETIMEDOUT, %eax
	je	4f
	cmpl	$-EINVAL, %eax
	jne	1b
4:	movl	%eax, %edx
	negl	%edx

3:	movl	%edx, %eax
7:	popl	%ebx
	cfi_adjust_cfa_offset(-4)
	cfi_restore(%ebx)
	popl	%ebp
	cfi_adjust_cfa_offset(-4)
	cfi_restore(%ebp)
	ret

8:	movl	$ETIMEDOUT, %eax
	jmp	7b

# ifndef __ASSUME_FUTEX_CLOCK_REALTIME
.Lreltmo:
	/* Check for a valid timeout value.  */
	cmpl	$1000000000, 4(%edx)
	jae	3f

	pushl	%esi
	cfi_adjust_cfa_offset(4)
	cfi_rel_offset(%esi, 0)
	pushl	%edi
	cfi_adjust_cfa_offset(4)
	cfi_rel_offset(%edi, 0)

	/* Stack frame for the timespec and timeval structs.  */
	subl	$8, %esp
	cfi_adjust_cfa_offset(8)

	movl	%ecx, %ebp
	movl	%edx, %edi

	movl	$2, %edx
	xchgl	%edx, (%ebp)

	test	%edx, %edx
	je	6f

1:
	/* Get current time.  */
	movl	%esp, %ebx
	xorl	%ecx, %ecx
	movl	$__NR_gettimeofday, %eax
	ENTER_KERNEL

	/* Compute relative timeout.  */
	movl	4(%esp), %eax
	movl	$1000, %edx
	mul	%edx		/* Milli seconds to nano seconds.  */
	movl	(%edi), %ecx
	movl	4(%edi), %edx
	subl	(%esp), %ecx
	subl	%eax, %edx
	jns	4f
	addl	$1000000000, %edx
	subl	$1, %ecx
4:	testl	%ecx, %ecx
	js	2f		/* Time is already up.  */

	/* Store relative timeout.  */
	movl	%ecx, (%esp)
	movl	%edx, 4(%esp)

	/* Futex call.  */
	movl	%ebp, %ebx
	movl	$2, %edx
	movl	%esp, %esi
	movl	16(%esp), %ecx
	LOAD_FUTEX_WAIT (%ecx)
	movl	$SYS_futex, %eax
	ENTER_KERNEL

	/* NB: %edx == 2 */
	xchgl	%edx, (%ebp)

	testl	%edx, %edx
	je	6f

	cmpl	$-ETIMEDOUT, %eax
	jne	1b
2:	movl	$ETIMEDOUT, %edx

6:	addl	$8, %esp
	cfi_adjust_cfa_offset(-8)
	popl	%edi
	cfi_adjust_cfa_offset(-4)
	cfi_restore(%edi)
	popl	%esi
	cfi_adjust_cfa_offset(-4)
	cfi_restore(%esi)
7:	popl	%ebx
	cfi_adjust_cfa_offset(-4)
	cfi_restore(%ebx)
	popl	%ebp
	cfi_adjust_cfa_offset(-4)
	cfi_restore(%ebp)
	movl	%edx, %eax
	ret

3:	movl	$EINVAL, %edx
	jmp	7b
# endif
	cfi_endproc
	.size	__lll_timedlock_wait,.-__lll_timedlock_wait
#endif

	.globl	__lll_unlock_wake_private
	.type	__lll_unlock_wake_private,@function
	.hidden	__lll_unlock_wake_private
	.align	16
__lll_unlock_wake_private:
	cfi_startproc
	pushl	%ebx
	cfi_adjust_cfa_offset(4)
	pushl	%ecx
	cfi_adjust_cfa_offset(4)
	pushl	%edx
	cfi_adjust_cfa_offset(4)
	cfi_offset(%ebx, -8)
	cfi_offset(%ecx, -12)
	cfi_offset(%edx, -16)

	movl	%eax, %ebx
	movl	$0, (%eax)
	LOAD_PRIVATE_FUTEX_WAKE (%ecx)
	movl	$1, %edx	/* Wake one thread.  */
	movl	$SYS_futex, %eax
	ENTER_KERNEL

	popl	%edx
	cfi_adjust_cfa_offset(-4)
	cfi_restore(%edx)
	popl	%ecx
	cfi_adjust_cfa_offset(-4)
	cfi_restore(%ecx)
	popl	%ebx
	cfi_adjust_cfa_offset(-4)
	cfi_restore(%ebx)
	ret
	cfi_endproc
	.size	__lll_unlock_wake_private,.-__lll_unlock_wake_private

#if !IS_IN (libc)
	.globl	__lll_unlock_wake
	.type	__lll_unlock_wake,@function
	.hidden	__lll_unlock_wake
	.align	16
__lll_unlock_wake:
	cfi_startproc
	pushl	%ebx
	cfi_adjust_cfa_offset(4)
	pushl	%ecx
	cfi_adjust_cfa_offset(4)
	pushl	%edx
	cfi_adjust_cfa_offset(4)
	cfi_offset(%ebx, -8)
	cfi_offset(%ecx, -12)
	cfi_offset(%edx, -16)

	movl	%eax, %ebx
	movl	$0, (%eax)
	LOAD_FUTEX_WAKE (%ecx)
	movl	$1, %edx	/* Wake one thread.  */
	movl	$SYS_futex, %eax
	ENTER_KERNEL

	popl	%edx
	cfi_adjust_cfa_offset(-4)
	cfi_restore(%edx)
	popl	%ecx
	cfi_adjust_cfa_offset(-4)
	cfi_restore(%ecx)
	popl	%ebx
	cfi_adjust_cfa_offset(-4)
	cfi_restore(%ebx)
	ret
	cfi_endproc
	.size	__lll_unlock_wake,.-__lll_unlock_wake

	.globl	__lll_timedwait_tid
	.type	__lll_timedwait_tid,@function
	.hidden	__lll_timedwait_tid
	.align	16
__lll_timedwait_tid:
	pushl	%edi
	pushl	%esi
	pushl	%ebx
	pushl	%ebp

	movl	%eax, %ebp
	movl	%edx, %edi
	subl	$8, %esp

	/* Get current time.  */
2:	movl	%esp, %ebx
	xorl	%ecx, %ecx
	movl	$__NR_gettimeofday, %eax
	ENTER_KERNEL

	/* Compute relative timeout.  */
	movl	4(%esp), %eax
	movl	$1000, %edx
	mul	%edx		/* Milli seconds to nano seconds.  */
	movl	(%edi), %ecx
	movl	4(%edi), %edx
	subl	(%esp), %ecx
	subl	%eax, %edx
	jns	5f
	addl	$1000000000, %edx
	subl	$1, %ecx
5:	testl	%ecx, %ecx
	js	6f		/* Time is already up.  */

	movl	%ecx, (%esp)	/* Store relative timeout.  */
	movl	%edx, 4(%esp)

	movl	(%ebp), %edx
	testl	%edx, %edx
	jz	4f

	movl	%esp, %esi
	/* XXX The kernel so far uses global futex for the wakeup at
	   all times.  */
	xorl	%ecx, %ecx	/* movl $FUTEX_WAIT, %ecx */
	movl	%ebp, %ebx
	movl	$SYS_futex, %eax
	ENTER_KERNEL

	cmpl	$0, (%ebx)
	jne	1f
4:	xorl	%eax, %eax

3:	addl	$8, %esp
	popl	%ebp
	popl	%ebx
	popl	%esi
	popl	%edi
	ret

1:	cmpl	$-ETIMEDOUT, %eax
	jne	2b
6:	movl	$ETIMEDOUT, %eax
	jmp	3b
	.size	__lll_timedwait_tid,.-__lll_timedwait_tid
#endif