Text file
src/runtime/sys_linux_arm.s
Documentation: runtime
1// Copyright 2009 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5//
6// System calls and other sys.stuff for arm, Linux
7//
8
9#include "go_asm.h"
10#include "go_tls.h"
11#include "textflag.h"
12
13#define CLOCK_REALTIME 0
14#define CLOCK_MONOTONIC 1
15
16// for EABI, as we don't support OABI
17#define SYS_BASE 0x0
18
19#define SYS_exit (SYS_BASE + 1)
20#define SYS_read (SYS_BASE + 3)
21#define SYS_write (SYS_BASE + 4)
22#define SYS_open (SYS_BASE + 5)
23#define SYS_close (SYS_BASE + 6)
24#define SYS_getpid (SYS_BASE + 20)
25#define SYS_kill (SYS_BASE + 37)
26#define SYS_clone (SYS_BASE + 120)
27#define SYS_rt_sigreturn (SYS_BASE + 173)
28#define SYS_rt_sigaction (SYS_BASE + 174)
29#define SYS_rt_sigprocmask (SYS_BASE + 175)
30#define SYS_sigaltstack (SYS_BASE + 186)
31#define SYS_mmap2 (SYS_BASE + 192)
32#define SYS_futex (SYS_BASE + 240)
33#define SYS_exit_group (SYS_BASE + 248)
34#define SYS_munmap (SYS_BASE + 91)
35#define SYS_madvise (SYS_BASE + 220)
36#define SYS_setitimer (SYS_BASE + 104)
37#define SYS_mincore (SYS_BASE + 219)
38#define SYS_gettid (SYS_BASE + 224)
39#define SYS_tgkill (SYS_BASE + 268)
40#define SYS_sched_yield (SYS_BASE + 158)
41#define SYS_nanosleep (SYS_BASE + 162)
42#define SYS_sched_getaffinity (SYS_BASE + 242)
43#define SYS_clock_gettime (SYS_BASE + 263)
44#define SYS_timer_create (SYS_BASE + 257)
45#define SYS_timer_settime (SYS_BASE + 258)
46#define SYS_timer_delete (SYS_BASE + 261)
47#define SYS_pipe2 (SYS_BASE + 359)
48#define SYS_access (SYS_BASE + 33)
49#define SYS_connect (SYS_BASE + 283)
50#define SYS_socket (SYS_BASE + 281)
51#define SYS_brk (SYS_BASE + 45)
52
53#define ARM_BASE (SYS_BASE + 0x0f0000)
54
55TEXT runtime·open(SB),NOSPLIT,$0
56 MOVW name+0(FP), R0
57 MOVW mode+4(FP), R1
58 MOVW perm+8(FP), R2
59 MOVW $SYS_open, R7
60 SWI $0
61 MOVW $0xfffff001, R1
62 CMP R1, R0
63 MOVW.HI $-1, R0
64 MOVW R0, ret+12(FP)
65 RET
66
67TEXT runtime·closefd(SB),NOSPLIT,$0
68 MOVW fd+0(FP), R0
69 MOVW $SYS_close, R7
70 SWI $0
71 MOVW $0xfffff001, R1
72 CMP R1, R0
73 MOVW.HI $-1, R0
74 MOVW R0, ret+4(FP)
75 RET
76
77TEXT runtime·write1(SB),NOSPLIT,$0
78 MOVW fd+0(FP), R0
79 MOVW p+4(FP), R1
80 MOVW n+8(FP), R2
81 MOVW $SYS_write, R7
82 SWI $0
83 MOVW R0, ret+12(FP)
84 RET
85
86TEXT runtime·read(SB),NOSPLIT,$0
87 MOVW fd+0(FP), R0
88 MOVW p+4(FP), R1
89 MOVW n+8(FP), R2
90 MOVW $SYS_read, R7
91 SWI $0
92 MOVW R0, ret+12(FP)
93 RET
94
95// func pipe2(flags int32) (r, w int32, errno int32)
96TEXT runtime·pipe2(SB),NOSPLIT,$0-16
97 MOVW $r+4(FP), R0
98 MOVW flags+0(FP), R1
99 MOVW $SYS_pipe2, R7
100 SWI $0
101 MOVW R0, errno+12(FP)
102 RET
103
104TEXT runtime·exit(SB),NOSPLIT|NOFRAME,$0
105 MOVW code+0(FP), R0
106 MOVW $SYS_exit_group, R7
107 SWI $0
108 MOVW $1234, R0
109 MOVW $1002, R1
110 MOVW R0, (R1) // fail hard
111
112TEXT exit1<>(SB),NOSPLIT|NOFRAME,$0
113 MOVW code+0(FP), R0
114 MOVW $SYS_exit, R7
115 SWI $0
116 MOVW $1234, R0
117 MOVW $1003, R1
118 MOVW R0, (R1) // fail hard
119
120// func exitThread(wait *atomic.Uint32)
121TEXT runtime·exitThread(SB),NOSPLIT|NOFRAME,$0-4
122 MOVW wait+0(FP), R0
123 // We're done using the stack.
124 // Alas, there's no reliable way to make this write atomic
125 // without potentially using the stack. So it goes.
126 MOVW $0, R1
127 MOVW R1, (R0)
128 MOVW $0, R0 // exit code
129 MOVW $SYS_exit, R7
130 SWI $0
131 MOVW $1234, R0
132 MOVW $1004, R1
133 MOVW R0, (R1) // fail hard
134 JMP 0(PC)
135
136TEXT runtime·gettid(SB),NOSPLIT,$0-4
137 MOVW $SYS_gettid, R7
138 SWI $0
139 MOVW R0, ret+0(FP)
140 RET
141
142TEXT runtime·raise(SB),NOSPLIT|NOFRAME,$0
143 MOVW $SYS_getpid, R7
144 SWI $0
145 MOVW R0, R4
146 MOVW $SYS_gettid, R7
147 SWI $0
148 MOVW R0, R1 // arg 2 tid
149 MOVW R4, R0 // arg 1 pid
150 MOVW sig+0(FP), R2 // arg 3
151 MOVW $SYS_tgkill, R7
152 SWI $0
153 RET
154
155TEXT runtime·raiseproc(SB),NOSPLIT|NOFRAME,$0
156 MOVW $SYS_getpid, R7
157 SWI $0
158 // arg 1 tid already in R0 from getpid
159 MOVW sig+0(FP), R1 // arg 2 - signal
160 MOVW $SYS_kill, R7
161 SWI $0
162 RET
163
164TEXT ·getpid(SB),NOSPLIT,$0-4
165 MOVW $SYS_getpid, R7
166 SWI $0
167 MOVW R0, ret+0(FP)
168 RET
169
170TEXT ·tgkill(SB),NOSPLIT,$0-12
171 MOVW tgid+0(FP), R0
172 MOVW tid+4(FP), R1
173 MOVW sig+8(FP), R2
174 MOVW $SYS_tgkill, R7
175 SWI $0
176 RET
177
178TEXT runtime·mmap(SB),NOSPLIT,$0
179 MOVW addr+0(FP), R0
180 MOVW n+4(FP), R1
181 MOVW prot+8(FP), R2
182 MOVW flags+12(FP), R3
183 MOVW fd+16(FP), R4
184 MOVW off+20(FP), R5
185 MOVW $SYS_mmap2, R7
186 SWI $0
187 MOVW $0xfffff001, R6
188 CMP R6, R0
189 MOVW $0, R1
190 RSB.HI $0, R0
191 MOVW.HI R0, R1 // if error, put in R1
192 MOVW.HI $0, R0
193 MOVW R0, p+24(FP)
194 MOVW R1, err+28(FP)
195 RET
196
197TEXT runtime·munmap(SB),NOSPLIT,$0
198 MOVW addr+0(FP), R0
199 MOVW n+4(FP), R1
200 MOVW $SYS_munmap, R7
201 SWI $0
202 MOVW $0xfffff001, R6
203 CMP R6, R0
204 MOVW.HI $0, R8 // crash on syscall failure
205 MOVW.HI R8, (R8)
206 RET
207
208TEXT runtime·madvise(SB),NOSPLIT,$0
209 MOVW addr+0(FP), R0
210 MOVW n+4(FP), R1
211 MOVW flags+8(FP), R2
212 MOVW $SYS_madvise, R7
213 SWI $0
214 MOVW R0, ret+12(FP)
215 RET
216
217TEXT runtime·setitimer(SB),NOSPLIT,$0
218 MOVW mode+0(FP), R0
219 MOVW new+4(FP), R1
220 MOVW old+8(FP), R2
221 MOVW $SYS_setitimer, R7
222 SWI $0
223 RET
224
225TEXT runtime·timer_create(SB),NOSPLIT,$0-16
226 MOVW clockid+0(FP), R0
227 MOVW sevp+4(FP), R1
228 MOVW timerid+8(FP), R2
229 MOVW $SYS_timer_create, R7
230 SWI $0
231 MOVW R0, ret+12(FP)
232 RET
233
234TEXT runtime·timer_settime(SB),NOSPLIT,$0-20
235 MOVW timerid+0(FP), R0
236 MOVW flags+4(FP), R1
237 MOVW new+8(FP), R2
238 MOVW old+12(FP), R3
239 MOVW $SYS_timer_settime, R7
240 SWI $0
241 MOVW R0, ret+16(FP)
242 RET
243
244TEXT runtime·timer_delete(SB),NOSPLIT,$0-8
245 MOVW timerid+0(FP), R0
246 MOVW $SYS_timer_delete, R7
247 SWI $0
248 MOVW R0, ret+4(FP)
249 RET
250
251TEXT runtime·mincore(SB),NOSPLIT,$0
252 MOVW addr+0(FP), R0
253 MOVW n+4(FP), R1
254 MOVW dst+8(FP), R2
255 MOVW $SYS_mincore, R7
256 SWI $0
257 MOVW R0, ret+12(FP)
258 RET
259
260// Call a VDSO function.
261//
262// R0-R3: arguments to VDSO function (C calling convention)
263// R4: uintptr function to call
264//
265// There is no return value.
266TEXT runtime·vdsoCall(SB),NOSPLIT,$8-0
267 // R0-R3 may be arguments to fn, do not touch.
268 // R4 is function to call.
269 // R5-R9 are available as locals. They are unchanged by the C call
270 // (callee-save).
271
272 // We don't know how much stack space the VDSO code will need,
273 // so switch to g0.
274
275 // Save old SP. Use R13 instead of SP to avoid linker rewriting the offsets.
276 MOVW R13, R5
277
278 MOVW g_m(g), R6
279
280 // Set vdsoPC and vdsoSP for SIGPROF traceback.
281 // Save the old values on stack and restore them on exit,
282 // so this function is reentrant.
283 MOVW m_vdsoPC(R6), R7
284 MOVW m_vdsoSP(R6), R8
285 MOVW R7, 4(R13)
286 MOVW R8, 8(R13)
287
288 MOVW $sp-4(FP), R7 // caller's SP
289 MOVW LR, m_vdsoPC(R6)
290 MOVW R7, m_vdsoSP(R6)
291
292 MOVW m_curg(R6), R7
293
294 CMP g, R7 // Only switch if on curg.
295 B.NE noswitch
296
297 MOVW m_g0(R6), R7
298 MOVW (g_sched+gobuf_sp)(R7), R13 // Set SP to g0 stack
299
300noswitch:
301 BIC $0x7, R13 // Align for C code
302
303 // Store g on gsignal's stack, so if we receive a signal
304 // during VDSO code we can find the g.
305
306 // When using cgo, we already saved g on TLS, also don't save g here.
307 MOVB runtime·iscgo(SB), R7
308 CMP $0, R7
309 BNE nosaveg
310 // If we don't have a signal stack, we won't receive signal, so don't
311 // bother saving g.
312 MOVW m_gsignal(R6), R7 // g.m.gsignal
313 CMP $0, R7
314 BEQ nosaveg
315 // Don't save g if we are already on the signal stack, as we won't get
316 // a nested signal.
317 CMP g, R7
318 BEQ nosaveg
319 // If we don't have a signal stack, we won't receive signal, so don't
320 // bother saving g.
321 MOVW (g_stack+stack_lo)(R7), R7 // g.m.gsignal.stack.lo
322 CMP $0, R7
323 BEQ nosaveg
324 MOVW g, (R7)
325
326 BL (R4)
327
328 MOVW $0, R8
329 MOVW R8, (R7) // clear g slot
330
331 JMP finish
332
333nosaveg:
334 BL (R4)
335
336finish:
337 MOVW R5, R13 // Restore real SP
338 // Restore vdsoPC, vdsoSP
339 // We don't worry about being signaled between the two stores.
340 // If we are not in a signal handler, we'll restore vdsoSP to 0,
341 // and no one will care about vdsoPC. If we are in a signal handler,
342 // we cannot receive another signal.
343 MOVW 8(R13), R7
344 MOVW R7, m_vdsoSP(R6)
345 MOVW 4(R13), R7
346 MOVW R7, m_vdsoPC(R6)
347 RET
348
349TEXT runtime·walltime(SB),NOSPLIT,$12-12
350 MOVW $CLOCK_REALTIME, R0
351 MOVW $spec-12(SP), R1 // timespec
352
353 MOVW runtime·vdsoClockgettimeSym(SB), R4
354 CMP $0, R4
355 B.EQ fallback
356
357 BL runtime·vdsoCall(SB)
358
359 JMP finish
360
361fallback:
362 MOVW $SYS_clock_gettime, R7
363 SWI $0
364
365finish:
366 MOVW sec-12(SP), R0 // sec
367 MOVW nsec-8(SP), R2 // nsec
368
369 MOVW R0, sec_lo+0(FP)
370 MOVW $0, R1
371 MOVW R1, sec_hi+4(FP)
372 MOVW R2, nsec+8(FP)
373 RET
374
375// func nanotime1() int64
376TEXT runtime·nanotime1(SB),NOSPLIT,$12-8
377 MOVW $CLOCK_MONOTONIC, R0
378 MOVW $spec-12(SP), R1 // timespec
379
380 MOVW runtime·vdsoClockgettimeSym(SB), R4
381 CMP $0, R4
382 B.EQ fallback
383
384 BL runtime·vdsoCall(SB)
385
386 JMP finish
387
388fallback:
389 MOVW $SYS_clock_gettime, R7
390 SWI $0
391
392finish:
393 MOVW sec-12(SP), R0 // sec
394 MOVW nsec-8(SP), R2 // nsec
395
396 MOVW $1000000000, R3
397 MULLU R0, R3, (R1, R0)
398 ADD.S R2, R0
399 ADC $0, R1 // Add carry bit to upper half.
400
401 MOVW R0, ret_lo+0(FP)
402 MOVW R1, ret_hi+4(FP)
403
404 RET
405
406// int32 futex(int32 *uaddr, int32 op, int32 val,
407// struct timespec *timeout, int32 *uaddr2, int32 val2);
408TEXT runtime·futex(SB),NOSPLIT,$0
409 MOVW addr+0(FP), R0
410 MOVW op+4(FP), R1
411 MOVW val+8(FP), R2
412 MOVW ts+12(FP), R3
413 MOVW addr2+16(FP), R4
414 MOVW val3+20(FP), R5
415 MOVW $SYS_futex, R7
416 SWI $0
417 MOVW R0, ret+24(FP)
418 RET
419
420// int32 clone(int32 flags, void *stack, M *mp, G *gp, void (*fn)(void));
421TEXT runtime·clone(SB),NOSPLIT,$0
422 MOVW flags+0(FP), R0
423 MOVW stk+4(FP), R1
424 MOVW $0, R2 // parent tid ptr
425 MOVW $0, R3 // tls_val
426 MOVW $0, R4 // child tid ptr
427 MOVW $0, R5
428
429 // Copy mp, gp, fn off parent stack for use by child.
430 MOVW $-16(R1), R1
431 MOVW mp+8(FP), R6
432 MOVW R6, 0(R1)
433 MOVW gp+12(FP), R6
434 MOVW R6, 4(R1)
435 MOVW fn+16(FP), R6
436 MOVW R6, 8(R1)
437 MOVW $1234, R6
438 MOVW R6, 12(R1)
439
440 MOVW $SYS_clone, R7
441 SWI $0
442
443 // In parent, return.
444 CMP $0, R0
445 BEQ 3(PC)
446 MOVW R0, ret+20(FP)
447 RET
448
449 // Paranoia: check that SP is as we expect. Use R13 to avoid linker 'fixup'
450 NOP R13 // tell vet SP/R13 changed - stop checking offsets
451 MOVW 12(R13), R0
452 MOVW $1234, R1
453 CMP R0, R1
454 BEQ 2(PC)
455 BL runtime·abort(SB)
456
457 MOVW 0(R13), R8 // m
458 MOVW 4(R13), R0 // g
459
460 CMP $0, R8
461 BEQ nog
462 CMP $0, R0
463 BEQ nog
464
465 MOVW R0, g
466 MOVW R8, g_m(g)
467
468 // paranoia; check they are not nil
469 MOVW 0(R8), R0
470 MOVW 0(g), R0
471
472 BL runtime·emptyfunc(SB) // fault if stack check is wrong
473
474 // Initialize m->procid to Linux tid
475 MOVW $SYS_gettid, R7
476 SWI $0
477 MOVW g_m(g), R8
478 MOVW R0, m_procid(R8)
479
480nog:
481 // Call fn
482 MOVW 8(R13), R0
483 MOVW $16(R13), R13
484 BL (R0)
485
486 // It shouldn't return. If it does, exit that thread.
487 SUB $16, R13 // restore the stack pointer to avoid memory corruption
488 MOVW $0, R0
489 MOVW R0, 4(R13)
490 BL exit1<>(SB)
491
492 MOVW $1234, R0
493 MOVW $1005, R1
494 MOVW R0, (R1)
495
496TEXT runtime·sigaltstack(SB),NOSPLIT,$0
497 MOVW new+0(FP), R0
498 MOVW old+4(FP), R1
499 MOVW $SYS_sigaltstack, R7
500 SWI $0
501 MOVW $0xfffff001, R6
502 CMP R6, R0
503 MOVW.HI $0, R8 // crash on syscall failure
504 MOVW.HI R8, (R8)
505 RET
506
507TEXT runtime·sigfwd(SB),NOSPLIT,$0-16
508 MOVW sig+4(FP), R0
509 MOVW info+8(FP), R1
510 MOVW ctx+12(FP), R2
511 MOVW fn+0(FP), R11
512 MOVW R13, R4
513 SUB $24, R13
514 BIC $0x7, R13 // alignment for ELF ABI
515 BL (R11)
516 MOVW R4, R13
517 RET
518
519TEXT runtime·sigtramp(SB),NOSPLIT|TOPFRAME,$0
520 // Reserve space for callee-save registers and arguments.
521 MOVM.DB.W [R4-R11], (R13)
522 SUB $16, R13
523
524 // this might be called in external code context,
525 // where g is not set.
526 // first save R0, because runtime·load_g will clobber it
527 MOVW R0, 4(R13)
528 MOVB runtime·iscgo(SB), R0
529 CMP $0, R0
530 BL.NE runtime·load_g(SB)
531
532 MOVW R1, 8(R13)
533 MOVW R2, 12(R13)
534 MOVW $runtime·sigtrampgo(SB), R11
535 BL (R11)
536
537 // Restore callee-save registers.
538 ADD $16, R13
539 MOVM.IA.W (R13), [R4-R11]
540
541 RET
542
543TEXT runtime·cgoSigtramp(SB),NOSPLIT,$0
544 MOVW $runtime·sigtramp(SB), R11
545 B (R11)
546
547TEXT runtime·rtsigprocmask(SB),NOSPLIT,$0
548 MOVW how+0(FP), R0
549 MOVW new+4(FP), R1
550 MOVW old+8(FP), R2
551 MOVW size+12(FP), R3
552 MOVW $SYS_rt_sigprocmask, R7
553 SWI $0
554 RET
555
556TEXT runtime·rt_sigaction(SB),NOSPLIT,$0
557 MOVW sig+0(FP), R0
558 MOVW new+4(FP), R1
559 MOVW old+8(FP), R2
560 MOVW size+12(FP), R3
561 MOVW $SYS_rt_sigaction, R7
562 SWI $0
563 MOVW R0, ret+16(FP)
564 RET
565
566TEXT runtime·usleep(SB),NOSPLIT,$12
567 MOVW usec+0(FP), R0
568 CALL runtime·usplitR0(SB)
569 MOVW R0, 4(R13)
570 MOVW $1000, R0 // usec to nsec
571 MUL R0, R1
572 MOVW R1, 8(R13)
573 MOVW $4(R13), R0
574 MOVW $0, R1
575 MOVW $SYS_nanosleep, R7
576 SWI $0
577 RET
578
579// As for cas, memory barriers are complicated on ARM, but the kernel
580// provides a user helper. ARMv5 does not support SMP and has no
581// memory barrier instruction at all. ARMv6 added SMP support and has
582// a memory barrier, but it requires writing to a coprocessor
583// register. ARMv7 introduced the DMB instruction, but it's expensive
584// even on single-core devices. The kernel helper takes care of all of
585// this for us.
586
587TEXT kernelPublicationBarrier<>(SB),NOSPLIT,$0
588 // void __kuser_memory_barrier(void);
589 MOVW $0xffff0fa0, R11
590 CALL (R11)
591 RET
592
593TEXT ·publicationBarrier(SB),NOSPLIT,$0
594 MOVB ·goarm(SB), R11
595 CMP $7, R11
596 BLT 2(PC)
597 JMP ·armPublicationBarrier(SB)
598 JMP kernelPublicationBarrier<>(SB) // extra layer so this function is leaf and no SP adjustment on GOARM=7
599
600TEXT runtime·osyield(SB),NOSPLIT,$0
601 MOVW $SYS_sched_yield, R7
602 SWI $0
603 RET
604
605TEXT runtime·sched_getaffinity(SB),NOSPLIT,$0
606 MOVW pid+0(FP), R0
607 MOVW len+4(FP), R1
608 MOVW buf+8(FP), R2
609 MOVW $SYS_sched_getaffinity, R7
610 SWI $0
611 MOVW R0, ret+12(FP)
612 RET
613
614// b __kuser_get_tls @ 0xffff0fe0
615TEXT runtime·read_tls_fallback(SB),NOSPLIT|NOFRAME,$0
616 MOVW $0xffff0fe0, R0
617 B (R0)
618
619TEXT runtime·access(SB),NOSPLIT,$0
620 MOVW name+0(FP), R0
621 MOVW mode+4(FP), R1
622 MOVW $SYS_access, R7
623 SWI $0
624 MOVW R0, ret+8(FP)
625 RET
626
627TEXT runtime·connect(SB),NOSPLIT,$0
628 MOVW fd+0(FP), R0
629 MOVW addr+4(FP), R1
630 MOVW len+8(FP), R2
631 MOVW $SYS_connect, R7
632 SWI $0
633 MOVW R0, ret+12(FP)
634 RET
635
636TEXT runtime·socket(SB),NOSPLIT,$0
637 MOVW domain+0(FP), R0
638 MOVW typ+4(FP), R1
639 MOVW prot+8(FP), R2
640 MOVW $SYS_socket, R7
641 SWI $0
642 MOVW R0, ret+12(FP)
643 RET
644
645// func sbrk0() uintptr
646TEXT runtime·sbrk0(SB),NOSPLIT,$0-4
647 // Implemented as brk(NULL).
648 MOVW $0, R0
649 MOVW $SYS_brk, R7
650 SWI $0
651 MOVW R0, ret+0(FP)
652 RET
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