summaryrefslogtreecommitdiffstats
path: root/src/runtime/sys_freebsd_amd64.s
blob: 95bf07e4f0fbcf15366ef66d567942c8d4d11467 (plain)
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
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//
// System calls and other sys.stuff for AMD64, FreeBSD
// /usr/src/sys/kern/syscalls.master for syscall numbers.
//

#include "go_asm.h"
#include "go_tls.h"
#include "textflag.h"
#include "cgo/abi_amd64.h"

#define CLOCK_REALTIME		0
#define CLOCK_MONOTONIC		4
#define FD_CLOEXEC		1
#define F_SETFD			2
#define AMD64_SET_FSBASE	129

#define SYS_exit		1
#define SYS_read		3
#define SYS_write		4
#define SYS_open		5
#define SYS_close		6
#define SYS_getpid		20
#define SYS_kill		37
#define SYS_sigaltstack		53
#define SYS_munmap		73
#define SYS_madvise		75
#define SYS_setitimer		83
#define SYS_fcntl		92
#define SYS_sysarch		165
#define SYS___sysctl		202
#define SYS_clock_gettime	232
#define SYS_nanosleep		240
#define SYS_issetugid		253
#define SYS_sched_yield		331
#define SYS_sigprocmask		340
#define SYS_kqueue		362
#define SYS_sigaction		416
#define SYS_thr_exit		431
#define SYS_thr_self		432
#define SYS_thr_kill		433
#define SYS__umtx_op		454
#define SYS_thr_new		455
#define SYS_mmap		477
#define SYS_cpuset_getaffinity	487
#define SYS_pipe2 		542
#define SYS_kevent		560

TEXT runtime·sys_umtx_op(SB),NOSPLIT,$0
	MOVQ addr+0(FP), DI
	MOVL mode+8(FP), SI
	MOVL val+12(FP), DX
	MOVQ uaddr1+16(FP), R10
	MOVQ ut+24(FP), R8
	MOVL $SYS__umtx_op, AX
	SYSCALL
	JCC	2(PC)
	NEGQ	AX
	MOVL	AX, ret+32(FP)
	RET

TEXT runtime·thr_new(SB),NOSPLIT,$0
	MOVQ param+0(FP), DI
	MOVL size+8(FP), SI
	MOVL $SYS_thr_new, AX
	SYSCALL
	JCC	2(PC)
	NEGQ	AX
	MOVL	AX, ret+16(FP)
	RET

TEXT runtime·thr_start(SB),NOSPLIT,$0
	MOVQ	DI, R13 // m

	// set up FS to point at m->tls
	LEAQ	m_tls(R13), DI
	CALL	runtime·settls(SB)	// smashes DI

	// set up m, g
	get_tls(CX)
	MOVQ	m_g0(R13), DI
	MOVQ	R13, g_m(DI)
	MOVQ	DI, g(CX)

	CALL	runtime·stackcheck(SB)
	CALL	runtime·mstart(SB)

	MOVQ 0, AX			// crash (not reached)

// Exit the entire program (like C exit)
TEXT runtime·exit(SB),NOSPLIT,$-8
	MOVL	code+0(FP), DI		// arg 1 exit status
	MOVL	$SYS_exit, AX
	SYSCALL
	MOVL	$0xf1, 0xf1  // crash
	RET

// func exitThread(wait *atomic.uint32)
TEXT runtime·exitThread(SB),NOSPLIT,$0-8
	MOVQ	wait+0(FP), AX
	// We're done using the stack.
	MOVL	$0, (AX)
	MOVL	$0, DI		// arg 1 long *state
	MOVL	$SYS_thr_exit, AX
	SYSCALL
	MOVL	$0xf1, 0xf1  // crash
	JMP	0(PC)

TEXT runtime·open(SB),NOSPLIT,$-8
	MOVQ	name+0(FP), DI		// arg 1 pathname
	MOVL	mode+8(FP), SI		// arg 2 flags
	MOVL	perm+12(FP), DX		// arg 3 mode
	MOVL	$SYS_open, AX
	SYSCALL
	JCC	2(PC)
	MOVL	$-1, AX
	MOVL	AX, ret+16(FP)
	RET

TEXT runtime·closefd(SB),NOSPLIT,$-8
	MOVL	fd+0(FP), DI		// arg 1 fd
	MOVL	$SYS_close, AX
	SYSCALL
	JCC	2(PC)
	MOVL	$-1, AX
	MOVL	AX, ret+8(FP)
	RET

TEXT runtime·read(SB),NOSPLIT,$-8
	MOVL	fd+0(FP), DI		// arg 1 fd
	MOVQ	p+8(FP), SI		// arg 2 buf
	MOVL	n+16(FP), DX		// arg 3 count
	MOVL	$SYS_read, AX
	SYSCALL
	JCC	2(PC)
	NEGQ	AX			// caller expects negative errno
	MOVL	AX, ret+24(FP)
	RET

// func pipe2(flags int32) (r, w int32, errno int32)
TEXT runtime·pipe2(SB),NOSPLIT,$0-20
	LEAQ	r+8(FP), DI
	MOVL	flags+0(FP), SI
	MOVL	$SYS_pipe2, AX
	SYSCALL
	JCC	2(PC)
	NEGQ	AX
	MOVL	AX, errno+16(FP)
	RET

TEXT runtime·write1(SB),NOSPLIT,$-8
	MOVQ	fd+0(FP), DI		// arg 1 fd
	MOVQ	p+8(FP), SI		// arg 2 buf
	MOVL	n+16(FP), DX		// arg 3 count
	MOVL	$SYS_write, AX
	SYSCALL
	JCC	2(PC)
	NEGQ	AX			// caller expects negative errno
	MOVL	AX, ret+24(FP)
	RET

TEXT runtime·thr_self(SB),NOSPLIT,$0-8
	// thr_self(&0(FP))
	LEAQ	ret+0(FP), DI	// arg 1
	MOVL	$SYS_thr_self, AX
	SYSCALL
	RET

TEXT runtime·thr_kill(SB),NOSPLIT,$0-16
	// thr_kill(tid, sig)
	MOVQ	tid+0(FP), DI	// arg 1 id
	MOVQ	sig+8(FP), SI	// arg 2 sig
	MOVL	$SYS_thr_kill, AX
	SYSCALL
	RET

TEXT runtime·raiseproc(SB),NOSPLIT,$0
	// getpid
	MOVL	$SYS_getpid, AX
	SYSCALL
	// kill(self, sig)
	MOVQ	AX, DI		// arg 1 pid
	MOVL	sig+0(FP), SI	// arg 2 sig
	MOVL	$SYS_kill, AX
	SYSCALL
	RET

TEXT runtime·setitimer(SB), NOSPLIT, $-8
	MOVL	mode+0(FP), DI
	MOVQ	new+8(FP), SI
	MOVQ	old+16(FP), DX
	MOVL	$SYS_setitimer, AX
	SYSCALL
	RET

// func fallback_walltime() (sec int64, nsec int32)
TEXT runtime·fallback_walltime(SB), NOSPLIT, $32-12
	MOVL	$SYS_clock_gettime, AX
	MOVQ	$CLOCK_REALTIME, DI
	LEAQ	8(SP), SI
	SYSCALL
	MOVQ	8(SP), AX	// sec
	MOVQ	16(SP), DX	// nsec

	// sec is in AX, nsec in DX
	MOVQ	AX, sec+0(FP)
	MOVL	DX, nsec+8(FP)
	RET

TEXT runtime·fallback_nanotime(SB), NOSPLIT, $32-8
	MOVL	$SYS_clock_gettime, AX
	MOVQ	$CLOCK_MONOTONIC, DI
	LEAQ	8(SP), SI
	SYSCALL
	MOVQ	8(SP), AX	// sec
	MOVQ	16(SP), DX	// nsec

	// sec is in AX, nsec in DX
	// return nsec in AX
	IMULQ	$1000000000, AX
	ADDQ	DX, AX
	MOVQ	AX, ret+0(FP)
	RET

TEXT runtime·asmSigaction(SB),NOSPLIT,$0
	MOVQ	sig+0(FP), DI		// arg 1 sig
	MOVQ	new+8(FP), SI		// arg 2 act
	MOVQ	old+16(FP), DX		// arg 3 oact
	MOVL	$SYS_sigaction, AX
	SYSCALL
	JCC	2(PC)
	MOVL	$-1, AX
	MOVL	AX, ret+24(FP)
	RET

TEXT runtime·callCgoSigaction(SB),NOSPLIT,$16
	MOVQ	sig+0(FP), DI		// arg 1 sig
	MOVQ	new+8(FP), SI		// arg 2 act
	MOVQ	old+16(FP), DX		// arg 3 oact
	MOVQ	_cgo_sigaction(SB), AX
	MOVQ	SP, BX			// callee-saved
	ANDQ	$~15, SP		// alignment as per amd64 psABI
	CALL	AX
	MOVQ	BX, SP
	MOVL	AX, ret+24(FP)
	RET

TEXT runtime·sigfwd(SB),NOSPLIT,$0-32
	MOVQ	fn+0(FP),    AX
	MOVL	sig+8(FP),   DI
	MOVQ	info+16(FP), SI
	MOVQ	ctx+24(FP),  DX
	PUSHQ	BP
	MOVQ	SP, BP
	ANDQ	$~15, SP     // alignment for x86_64 ABI
	CALL	AX
	MOVQ	BP, SP
	POPQ	BP
	RET

// Called using C ABI.
TEXT runtime·sigtramp(SB),NOSPLIT|TOPFRAME,$0
	// Transition from C ABI to Go ABI.
	PUSH_REGS_HOST_TO_ABI0()

	// Set up ABIInternal environment: g in R14, cleared X15.
	get_tls(R12)
	MOVQ	g(R12), R14
	PXOR	X15, X15

	// Reserve space for spill slots.
	NOP	SP		// disable vet stack checking
	ADJSP   $24

	// Call into the Go signal handler
	MOVQ	DI, AX	// sig
	MOVQ	SI, BX	// info
	MOVQ	DX, CX	// ctx
	CALL	·sigtrampgo<ABIInternal>(SB)

	ADJSP	$-24

        POP_REGS_HOST_TO_ABI0()
	RET

// Called using C ABI.
TEXT runtime·sigprofNonGoWrapper<>(SB),NOSPLIT,$0
	// Transition from C ABI to Go ABI.
	PUSH_REGS_HOST_TO_ABI0()

	// Set up ABIInternal environment: g in R14, cleared X15.
	get_tls(R12)
	MOVQ	g(R12), R14
	PXOR	X15, X15

	// Reserve space for spill slots.
	NOP	SP		// disable vet stack checking
	ADJSP   $24

	// Call into the Go signal handler
	MOVQ	DI, AX	// sig
	MOVQ	SI, BX	// info
	MOVQ	DX, CX	// ctx
	CALL	·sigprofNonGo<ABIInternal>(SB)

	ADJSP	$-24

	POP_REGS_HOST_TO_ABI0()
	RET

// Used instead of sigtramp in programs that use cgo.
// Arguments from kernel are in DI, SI, DX.
TEXT runtime·cgoSigtramp(SB),NOSPLIT,$0
	// If no traceback function, do usual sigtramp.
	MOVQ	runtime·cgoTraceback(SB), AX
	TESTQ	AX, AX
	JZ	sigtramp

	// If no traceback support function, which means that
	// runtime/cgo was not linked in, do usual sigtramp.
	MOVQ	_cgo_callers(SB), AX
	TESTQ	AX, AX
	JZ	sigtramp

	// Figure out if we are currently in a cgo call.
	// If not, just do usual sigtramp.
	get_tls(CX)
	MOVQ	g(CX),AX
	TESTQ	AX, AX
	JZ	sigtrampnog     // g == nil
	MOVQ	g_m(AX), AX
	TESTQ	AX, AX
	JZ	sigtramp        // g.m == nil
	MOVL	m_ncgo(AX), CX
	TESTL	CX, CX
	JZ	sigtramp        // g.m.ncgo == 0
	MOVQ	m_curg(AX), CX
	TESTQ	CX, CX
	JZ	sigtramp        // g.m.curg == nil
	MOVQ	g_syscallsp(CX), CX
	TESTQ	CX, CX
	JZ	sigtramp        // g.m.curg.syscallsp == 0
	MOVQ	m_cgoCallers(AX), R8
	TESTQ	R8, R8
	JZ	sigtramp        // g.m.cgoCallers == nil
	MOVL	m_cgoCallersUse(AX), CX
	TESTL	CX, CX
	JNZ	sigtramp	// g.m.cgoCallersUse != 0

	// Jump to a function in runtime/cgo.
	// That function, written in C, will call the user's traceback
	// function with proper unwind info, and will then call back here.
	// The first three arguments, and the fifth, are already in registers.
	// Set the two remaining arguments now.
	MOVQ	runtime·cgoTraceback(SB), CX
	MOVQ	$runtime·sigtramp(SB), R9
	MOVQ	_cgo_callers(SB), AX
	JMP	AX

sigtramp:
	JMP	runtime·sigtramp(SB)

sigtrampnog:
	// Signal arrived on a non-Go thread. If this is SIGPROF, get a
	// stack trace.
	CMPL	DI, $27 // 27 == SIGPROF
	JNZ	sigtramp

	// Lock sigprofCallersUse.
	MOVL	$0, AX
	MOVL	$1, CX
	MOVQ	$runtime·sigprofCallersUse(SB), R11
	LOCK
	CMPXCHGL	CX, 0(R11)
	JNZ	sigtramp  // Skip stack trace if already locked.

	// Jump to the traceback function in runtime/cgo.
	// It will call back to sigprofNonGo, via sigprofNonGoWrapper, to convert
	// the arguments to the Go calling convention.
	// First three arguments to traceback function are in registers already.
	MOVQ	runtime·cgoTraceback(SB), CX
	MOVQ	$runtime·sigprofCallers(SB), R8
	MOVQ	$runtime·sigprofNonGoWrapper<>(SB), R9
	MOVQ	_cgo_callers(SB), AX
	JMP	AX

TEXT runtime·sysMmap(SB),NOSPLIT,$0
	MOVQ	addr+0(FP), DI		// arg 1 addr
	MOVQ	n+8(FP), SI		// arg 2 len
	MOVL	prot+16(FP), DX		// arg 3 prot
	MOVL	flags+20(FP), R10		// arg 4 flags
	MOVL	fd+24(FP), R8		// arg 5 fid
	MOVL	off+28(FP), R9		// arg 6 offset
	MOVL	$SYS_mmap, AX
	SYSCALL
	JCC	ok
	MOVQ	$0, p+32(FP)
	MOVQ	AX, err+40(FP)
	RET
ok:
	MOVQ	AX, p+32(FP)
	MOVQ	$0, err+40(FP)
	RET

// Call the function stored in _cgo_mmap using the GCC calling convention.
// This must be called on the system stack.
TEXT runtime·callCgoMmap(SB),NOSPLIT,$16
	MOVQ	addr+0(FP), DI
	MOVQ	n+8(FP), SI
	MOVL	prot+16(FP), DX
	MOVL	flags+20(FP), CX
	MOVL	fd+24(FP), R8
	MOVL	off+28(FP), R9
	MOVQ	_cgo_mmap(SB), AX
	MOVQ	SP, BX
	ANDQ	$~15, SP	// alignment as per amd64 psABI
	MOVQ	BX, 0(SP)
	CALL	AX
	MOVQ	0(SP), SP
	MOVQ	AX, ret+32(FP)
	RET

TEXT runtime·sysMunmap(SB),NOSPLIT,$0
	MOVQ	addr+0(FP), DI		// arg 1 addr
	MOVQ	n+8(FP), SI		// arg 2 len
	MOVL	$SYS_munmap, AX
	SYSCALL
	JCC	2(PC)
	MOVL	$0xf1, 0xf1  // crash
	RET

// Call the function stored in _cgo_munmap using the GCC calling convention.
// This must be called on the system stack.
TEXT runtime·callCgoMunmap(SB),NOSPLIT,$16-16
	MOVQ	addr+0(FP), DI
	MOVQ	n+8(FP), SI
	MOVQ	_cgo_munmap(SB), AX
	MOVQ	SP, BX
	ANDQ	$~15, SP	// alignment as per amd64 psABI
	MOVQ	BX, 0(SP)
	CALL	AX
	MOVQ	0(SP), SP
	RET

TEXT runtime·madvise(SB),NOSPLIT,$0
	MOVQ	addr+0(FP), DI
	MOVQ	n+8(FP), SI
	MOVL	flags+16(FP), DX
	MOVQ	$SYS_madvise, AX
	SYSCALL
	JCC	2(PC)
	MOVL	$-1, AX
	MOVL	AX, ret+24(FP)
	RET

TEXT runtime·sigaltstack(SB),NOSPLIT,$-8
	MOVQ	new+0(FP), DI
	MOVQ	old+8(FP), SI
	MOVQ	$SYS_sigaltstack, AX
	SYSCALL
	JCC	2(PC)
	MOVL	$0xf1, 0xf1  // crash
	RET

TEXT runtime·usleep(SB),NOSPLIT,$16
	MOVL	$0, DX
	MOVL	usec+0(FP), AX
	MOVL	$1000000, CX
	DIVL	CX
	MOVQ	AX, 0(SP)		// tv_sec
	MOVL	$1000, AX
	MULL	DX
	MOVQ	AX, 8(SP)		// tv_nsec

	MOVQ	SP, DI			// arg 1 - rqtp
	MOVQ	$0, SI			// arg 2 - rmtp
	MOVL	$SYS_nanosleep, AX
	SYSCALL
	RET

// set tls base to DI
TEXT runtime·settls(SB),NOSPLIT,$8
	ADDQ	$8, DI	// adjust for ELF: wants to use -8(FS) for g and m
	MOVQ	DI, 0(SP)
	MOVQ	SP, SI
	MOVQ	$AMD64_SET_FSBASE, DI
	MOVQ	$SYS_sysarch, AX
	SYSCALL
	JCC	2(PC)
	MOVL	$0xf1, 0xf1  // crash
	RET

TEXT runtime·sysctl(SB),NOSPLIT,$0
	MOVQ	mib+0(FP), DI		// arg 1 - name
	MOVL	miblen+8(FP), SI		// arg 2 - namelen
	MOVQ	out+16(FP), DX		// arg 3 - oldp
	MOVQ	size+24(FP), R10		// arg 4 - oldlenp
	MOVQ	dst+32(FP), R8		// arg 5 - newp
	MOVQ	ndst+40(FP), R9		// arg 6 - newlen
	MOVQ	$SYS___sysctl, AX
	SYSCALL
	JCC 4(PC)
	NEGQ	AX
	MOVL	AX, ret+48(FP)
	RET
	MOVL	$0, AX
	MOVL	AX, ret+48(FP)
	RET

TEXT runtime·osyield(SB),NOSPLIT,$-4
	MOVL	$SYS_sched_yield, AX
	SYSCALL
	RET

TEXT runtime·sigprocmask(SB),NOSPLIT,$0
	MOVL	how+0(FP), DI		// arg 1 - how
	MOVQ	new+8(FP), SI		// arg 2 - set
	MOVQ	old+16(FP), DX		// arg 3 - oset
	MOVL	$SYS_sigprocmask, AX
	SYSCALL
	JAE	2(PC)
	MOVL	$0xf1, 0xf1  // crash
	RET

// int32 runtime·kqueue(void);
TEXT runtime·kqueue(SB),NOSPLIT,$0
	MOVQ	$0, DI
	MOVQ	$0, SI
	MOVQ	$0, DX
	MOVL	$SYS_kqueue, AX
	SYSCALL
	JCC	2(PC)
	NEGQ	AX
	MOVL	AX, ret+0(FP)
	RET

// int32 runtime·kevent(int kq, Kevent *changelist, int nchanges, Kevent *eventlist, int nevents, Timespec *timeout);
TEXT runtime·kevent(SB),NOSPLIT,$0
	MOVL	kq+0(FP), DI
	MOVQ	ch+8(FP), SI
	MOVL	nch+16(FP), DX
	MOVQ	ev+24(FP), R10
	MOVL	nev+32(FP), R8
	MOVQ	ts+40(FP), R9
	MOVL	$SYS_kevent, AX
	SYSCALL
	JCC	2(PC)
	NEGQ	AX
	MOVL	AX, ret+48(FP)
	RET

// func fcntl(fd, cmd, arg int32) (int32, int32)
TEXT runtime·fcntl(SB),NOSPLIT,$0
	MOVL	fd+0(FP), DI	// fd
	MOVL	cmd+4(FP), SI	// cmd
	MOVL	arg+8(FP), DX	// arg
	MOVL	$SYS_fcntl, AX
	SYSCALL
	JCC	noerr
	MOVL	$-1, ret+16(FP)
	MOVL	AX, errno+20(FP)
	RET
noerr:
	MOVL	AX, ret+16(FP)
	MOVL	$0, errno+20(FP)
	RET

// void runtime·closeonexec(int32 fd);
TEXT runtime·closeonexec(SB),NOSPLIT,$0
	MOVL	fd+0(FP), DI	// fd
	MOVQ	$F_SETFD, SI
	MOVQ	$FD_CLOEXEC, DX
	MOVL	$SYS_fcntl, AX
	SYSCALL
	RET

// func cpuset_getaffinity(level int, which int, id int64, size int, mask *byte) int32
TEXT runtime·cpuset_getaffinity(SB), NOSPLIT, $0-44
	MOVQ	level+0(FP), DI
	MOVQ	which+8(FP), SI
	MOVQ	id+16(FP), DX
	MOVQ	size+24(FP), R10
	MOVQ	mask+32(FP), R8
	MOVL	$SYS_cpuset_getaffinity, AX
	SYSCALL
	JCC	2(PC)
	NEGQ	AX
	MOVL	AX, ret+40(FP)
	RET

// func issetugid() int32
TEXT runtime·issetugid(SB),NOSPLIT,$0
	MOVQ	$0, DI
	MOVQ	$0, SI
	MOVQ	$0, DX
	MOVL	$SYS_issetugid, AX
	SYSCALL
	MOVL	AX, ret+0(FP)
	RET