Text file
src/runtime/asm_s390x.s
1 // Copyright 2016 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 #include "go_asm.h"
6 #include "go_tls.h"
7 #include "funcdata.h"
8 #include "textflag.h"
9
10 // _rt0_s390x_lib is common startup code for s390x systems when
11 // using -buildmode=c-archive or -buildmode=c-shared. The linker will
12 // arrange to invoke this function as a global constructor (for
13 // c-archive) or when the shared library is loaded (for c-shared).
14 // We expect argc and argv to be passed in the usual C ABI registers
15 // R2 and R3.
16 TEXT _rt0_s390x_lib(SB), NOSPLIT|NOFRAME, $0
17 STMG R6, R15, 48(R15)
18 MOVD R2, _rt0_s390x_lib_argc<>(SB)
19 MOVD R3, _rt0_s390x_lib_argv<>(SB)
20
21 // Save R6-R15 in the register save area of the calling function.
22 STMG R6, R15, 48(R15)
23
24 // Allocate 80 bytes on the stack.
25 MOVD $-80(R15), R15
26
27 // Save F8-F15 in our stack frame.
28 FMOVD F8, 16(R15)
29 FMOVD F9, 24(R15)
30 FMOVD F10, 32(R15)
31 FMOVD F11, 40(R15)
32 FMOVD F12, 48(R15)
33 FMOVD F13, 56(R15)
34 FMOVD F14, 64(R15)
35 FMOVD F15, 72(R15)
36
37 // Synchronous initialization.
38 MOVD $runtime·libpreinit(SB), R1
39 BL R1
40
41 // Create a new thread to finish Go runtime initialization.
42 MOVD _cgo_sys_thread_create(SB), R1
43 CMP R1, $0
44 BEQ nocgo
45 MOVD $_rt0_s390x_lib_go(SB), R2
46 MOVD $0, R3
47 BL R1
48 BR restore
49
50 nocgo:
51 MOVD $0x800000, R1 // stacksize
52 MOVD R1, 0(R15)
53 MOVD $_rt0_s390x_lib_go(SB), R1
54 MOVD R1, 8(R15) // fn
55 MOVD $runtime·newosproc(SB), R1
56 BL R1
57
58 restore:
59 // Restore F8-F15 from our stack frame.
60 FMOVD 16(R15), F8
61 FMOVD 24(R15), F9
62 FMOVD 32(R15), F10
63 FMOVD 40(R15), F11
64 FMOVD 48(R15), F12
65 FMOVD 56(R15), F13
66 FMOVD 64(R15), F14
67 FMOVD 72(R15), F15
68 MOVD $80(R15), R15
69
70 // Restore R6-R15.
71 LMG 48(R15), R6, R15
72 RET
73
74 // _rt0_s390x_lib_go initializes the Go runtime.
75 // This is started in a separate thread by _rt0_s390x_lib.
76 TEXT _rt0_s390x_lib_go(SB), NOSPLIT|NOFRAME, $0
77 MOVD _rt0_s390x_lib_argc<>(SB), R2
78 MOVD _rt0_s390x_lib_argv<>(SB), R3
79 MOVD $runtime·rt0_go(SB), R1
80 BR R1
81
82 DATA _rt0_s390x_lib_argc<>(SB)/8, $0
83 GLOBL _rt0_s390x_lib_argc<>(SB), NOPTR, $8
84 DATA _rt0_s90x_lib_argv<>(SB)/8, $0
85 GLOBL _rt0_s390x_lib_argv<>(SB), NOPTR, $8
86
87 TEXT runtime·rt0_go(SB),NOSPLIT|TOPFRAME,$0
88 // R2 = argc; R3 = argv; R11 = temp; R13 = g; R15 = stack pointer
89 // C TLS base pointer in AR0:AR1
90
91 // initialize essential registers
92 XOR R0, R0
93
94 SUB $24, R15
95 MOVW R2, 8(R15) // argc
96 MOVD R3, 16(R15) // argv
97
98 // create istack out of the given (operating system) stack.
99 // _cgo_init may update stackguard.
100 MOVD $runtime·g0(SB), g
101 MOVD R15, R11
102 SUB $(64*1024), R11
103 MOVD R11, g_stackguard0(g)
104 MOVD R11, g_stackguard1(g)
105 MOVD R11, (g_stack+stack_lo)(g)
106 MOVD R15, (g_stack+stack_hi)(g)
107
108 // if there is a _cgo_init, call it using the gcc ABI.
109 MOVD _cgo_init(SB), R11
110 CMPBEQ R11, $0, nocgo
111 MOVW AR0, R4 // (AR0 << 32 | AR1) is the TLS base pointer; MOVD is translated to EAR
112 SLD $32, R4, R4
113 MOVW AR1, R4 // arg 2: TLS base pointer
114 MOVD $setg_gcc<>(SB), R3 // arg 1: setg
115 MOVD g, R2 // arg 0: G
116 // C functions expect 160 bytes of space on caller stack frame
117 // and an 8-byte aligned stack pointer
118 MOVD R15, R9 // save current stack (R9 is preserved in the Linux ABI)
119 SUB $160, R15 // reserve 160 bytes
120 MOVD $~7, R6
121 AND R6, R15 // 8-byte align
122 BL R11 // this call clobbers volatile registers according to Linux ABI (R0-R5, R14)
123 MOVD R9, R15 // restore stack
124 XOR R0, R0 // zero R0
125
126 nocgo:
127 // update stackguard after _cgo_init
128 MOVD (g_stack+stack_lo)(g), R2
129 ADD $const__StackGuard, R2
130 MOVD R2, g_stackguard0(g)
131 MOVD R2, g_stackguard1(g)
132
133 // set the per-goroutine and per-mach "registers"
134 MOVD $runtime·m0(SB), R2
135
136 // save m->g0 = g0
137 MOVD g, m_g0(R2)
138 // save m0 to g0->m
139 MOVD R2, g_m(g)
140
141 BL runtime·check(SB)
142
143 // argc/argv are already prepared on stack
144 BL runtime·args(SB)
145 BL runtime·osinit(SB)
146 BL runtime·schedinit(SB)
147
148 // create a new goroutine to start program
149 MOVD $runtime·mainPC(SB), R2 // entry
150 SUB $16, R15
151 MOVD R2, 8(R15)
152 MOVD $0, 0(R15)
153 BL runtime·newproc(SB)
154 ADD $16, R15
155
156 // start this M
157 BL runtime·mstart(SB)
158
159 MOVD $0, 1(R0)
160 RET
161
162 DATA runtime·mainPC+0(SB)/8,$runtime·main(SB)
163 GLOBL runtime·mainPC(SB),RODATA,$8
164
165 TEXT runtime·breakpoint(SB),NOSPLIT|NOFRAME,$0-0
166 MOVD $0, 2(R0)
167 RET
168
169 TEXT runtime·asminit(SB),NOSPLIT|NOFRAME,$0-0
170 RET
171
172 TEXT runtime·mstart(SB),NOSPLIT|TOPFRAME,$0
173 CALL runtime·mstart0(SB)
174 RET // not reached
175
176 /*
177 * go-routine
178 */
179
180 // void gogo(Gobuf*)
181 // restore state from Gobuf; longjmp
182 TEXT runtime·gogo(SB), NOSPLIT|NOFRAME, $0-8
183 MOVD buf+0(FP), R5
184 MOVD gobuf_g(R5), R6
185 MOVD 0(R6), R7 // make sure g != nil
186 BR gogo<>(SB)
187
188 TEXT gogo<>(SB), NOSPLIT|NOFRAME, $0
189 MOVD R6, g
190 BL runtime·save_g(SB)
191
192 MOVD 0(g), R4
193 MOVD gobuf_sp(R5), R15
194 MOVD gobuf_lr(R5), LR
195 MOVD gobuf_ret(R5), R3
196 MOVD gobuf_ctxt(R5), R12
197 MOVD $0, gobuf_sp(R5)
198 MOVD $0, gobuf_ret(R5)
199 MOVD $0, gobuf_lr(R5)
200 MOVD $0, gobuf_ctxt(R5)
201 CMP R0, R0 // set condition codes for == test, needed by stack split
202 MOVD gobuf_pc(R5), R6
203 BR (R6)
204
205 // void mcall(fn func(*g))
206 // Switch to m->g0's stack, call fn(g).
207 // Fn must never return. It should gogo(&g->sched)
208 // to keep running g.
209 TEXT runtime·mcall(SB), NOSPLIT, $-8-8
210 // Save caller state in g->sched
211 MOVD R15, (g_sched+gobuf_sp)(g)
212 MOVD LR, (g_sched+gobuf_pc)(g)
213 MOVD $0, (g_sched+gobuf_lr)(g)
214
215 // Switch to m->g0 & its stack, call fn.
216 MOVD g, R3
217 MOVD g_m(g), R8
218 MOVD m_g0(R8), g
219 BL runtime·save_g(SB)
220 CMP g, R3
221 BNE 2(PC)
222 BR runtime·badmcall(SB)
223 MOVD fn+0(FP), R12 // context
224 MOVD 0(R12), R4 // code pointer
225 MOVD (g_sched+gobuf_sp)(g), R15 // sp = m->g0->sched.sp
226 SUB $16, R15
227 MOVD R3, 8(R15)
228 MOVD $0, 0(R15)
229 BL (R4)
230 BR runtime·badmcall2(SB)
231
232 // systemstack_switch is a dummy routine that systemstack leaves at the bottom
233 // of the G stack. We need to distinguish the routine that
234 // lives at the bottom of the G stack from the one that lives
235 // at the top of the system stack because the one at the top of
236 // the system stack terminates the stack walk (see topofstack()).
237 TEXT runtime·systemstack_switch(SB), NOSPLIT, $0-0
238 UNDEF
239 BL (LR) // make sure this function is not leaf
240 RET
241
242 // func systemstack(fn func())
243 TEXT runtime·systemstack(SB), NOSPLIT, $0-8
244 MOVD fn+0(FP), R3 // R3 = fn
245 MOVD R3, R12 // context
246 MOVD g_m(g), R4 // R4 = m
247
248 MOVD m_gsignal(R4), R5 // R5 = gsignal
249 CMPBEQ g, R5, noswitch
250
251 MOVD m_g0(R4), R5 // R5 = g0
252 CMPBEQ g, R5, noswitch
253
254 MOVD m_curg(R4), R6
255 CMPBEQ g, R6, switch
256
257 // Bad: g is not gsignal, not g0, not curg. What is it?
258 // Hide call from linker nosplit analysis.
259 MOVD $runtime·badsystemstack(SB), R3
260 BL (R3)
261 BL runtime·abort(SB)
262
263 switch:
264 // save our state in g->sched. Pretend to
265 // be systemstack_switch if the G stack is scanned.
266 BL gosave_systemstack_switch<>(SB)
267
268 // switch to g0
269 MOVD R5, g
270 BL runtime·save_g(SB)
271 MOVD (g_sched+gobuf_sp)(g), R15
272
273 // call target function
274 MOVD 0(R12), R3 // code pointer
275 BL (R3)
276
277 // switch back to g
278 MOVD g_m(g), R3
279 MOVD m_curg(R3), g
280 BL runtime·save_g(SB)
281 MOVD (g_sched+gobuf_sp)(g), R15
282 MOVD $0, (g_sched+gobuf_sp)(g)
283 RET
284
285 noswitch:
286 // already on m stack, just call directly
287 // Using a tail call here cleans up tracebacks since we won't stop
288 // at an intermediate systemstack.
289 MOVD 0(R12), R3 // code pointer
290 MOVD 0(R15), LR // restore LR
291 ADD $8, R15
292 BR (R3)
293
294 /*
295 * support for morestack
296 */
297
298 // Called during function prolog when more stack is needed.
299 // Caller has already loaded:
300 // R3: framesize, R4: argsize, R5: LR
301 //
302 // The traceback routines see morestack on a g0 as being
303 // the top of a stack (for example, morestack calling newstack
304 // calling the scheduler calling newm calling gc), so we must
305 // record an argument size. For that purpose, it has no arguments.
306 TEXT runtime·morestack(SB),NOSPLIT|NOFRAME,$0-0
307 // Cannot grow scheduler stack (m->g0).
308 MOVD g_m(g), R7
309 MOVD m_g0(R7), R8
310 CMPBNE g, R8, 3(PC)
311 BL runtime·badmorestackg0(SB)
312 BL runtime·abort(SB)
313
314 // Cannot grow signal stack (m->gsignal).
315 MOVD m_gsignal(R7), R8
316 CMP g, R8
317 BNE 3(PC)
318 BL runtime·badmorestackgsignal(SB)
319 BL runtime·abort(SB)
320
321 // Called from f.
322 // Set g->sched to context in f.
323 MOVD R15, (g_sched+gobuf_sp)(g)
324 MOVD LR, R8
325 MOVD R8, (g_sched+gobuf_pc)(g)
326 MOVD R5, (g_sched+gobuf_lr)(g)
327 MOVD R12, (g_sched+gobuf_ctxt)(g)
328
329 // Called from f.
330 // Set m->morebuf to f's caller.
331 MOVD R5, (m_morebuf+gobuf_pc)(R7) // f's caller's PC
332 MOVD R15, (m_morebuf+gobuf_sp)(R7) // f's caller's SP
333 MOVD g, (m_morebuf+gobuf_g)(R7)
334
335 // Call newstack on m->g0's stack.
336 MOVD m_g0(R7), g
337 BL runtime·save_g(SB)
338 MOVD (g_sched+gobuf_sp)(g), R15
339 // Create a stack frame on g0 to call newstack.
340 MOVD $0, -8(R15) // Zero saved LR in frame
341 SUB $8, R15
342 BL runtime·newstack(SB)
343
344 // Not reached, but make sure the return PC from the call to newstack
345 // is still in this function, and not the beginning of the next.
346 UNDEF
347
348 TEXT runtime·morestack_noctxt(SB),NOSPLIT|NOFRAME,$0-0
349 MOVD $0, R12
350 BR runtime·morestack(SB)
351
352 // reflectcall: call a function with the given argument list
353 // func call(stackArgsType *_type, f *FuncVal, stackArgs *byte, stackArgsSize, stackRetOffset, frameSize uint32, regArgs *abi.RegArgs).
354 // we don't have variable-sized frames, so we use a small number
355 // of constant-sized-frame functions to encode a few bits of size in the pc.
356 // Caution: ugly multiline assembly macros in your future!
357
358 #define DISPATCH(NAME,MAXSIZE) \
359 MOVD $MAXSIZE, R4; \
360 CMP R3, R4; \
361 BGT 3(PC); \
362 MOVD $NAME(SB), R5; \
363 BR (R5)
364 // Note: can't just "BR NAME(SB)" - bad inlining results.
365
366 TEXT ·reflectcall(SB), NOSPLIT, $-8-48
367 MOVWZ frameSize+32(FP), R3
368 DISPATCH(runtime·call16, 16)
369 DISPATCH(runtime·call32, 32)
370 DISPATCH(runtime·call64, 64)
371 DISPATCH(runtime·call128, 128)
372 DISPATCH(runtime·call256, 256)
373 DISPATCH(runtime·call512, 512)
374 DISPATCH(runtime·call1024, 1024)
375 DISPATCH(runtime·call2048, 2048)
376 DISPATCH(runtime·call4096, 4096)
377 DISPATCH(runtime·call8192, 8192)
378 DISPATCH(runtime·call16384, 16384)
379 DISPATCH(runtime·call32768, 32768)
380 DISPATCH(runtime·call65536, 65536)
381 DISPATCH(runtime·call131072, 131072)
382 DISPATCH(runtime·call262144, 262144)
383 DISPATCH(runtime·call524288, 524288)
384 DISPATCH(runtime·call1048576, 1048576)
385 DISPATCH(runtime·call2097152, 2097152)
386 DISPATCH(runtime·call4194304, 4194304)
387 DISPATCH(runtime·call8388608, 8388608)
388 DISPATCH(runtime·call16777216, 16777216)
389 DISPATCH(runtime·call33554432, 33554432)
390 DISPATCH(runtime·call67108864, 67108864)
391 DISPATCH(runtime·call134217728, 134217728)
392 DISPATCH(runtime·call268435456, 268435456)
393 DISPATCH(runtime·call536870912, 536870912)
394 DISPATCH(runtime·call1073741824, 1073741824)
395 MOVD $runtime·badreflectcall(SB), R5
396 BR (R5)
397
398 #define CALLFN(NAME,MAXSIZE) \
399 TEXT NAME(SB), WRAPPER, $MAXSIZE-48; \
400 NO_LOCAL_POINTERS; \
401 /* copy arguments to stack */ \
402 MOVD stackArgs+16(FP), R4; \
403 MOVWZ stackArgsSize+24(FP), R5; \
404 MOVD $stack-MAXSIZE(SP), R6; \
405 loopArgs: /* copy 256 bytes at a time */ \
406 CMP R5, $256; \
407 BLT tailArgs; \
408 SUB $256, R5; \
409 MVC $256, 0(R4), 0(R6); \
410 MOVD $256(R4), R4; \
411 MOVD $256(R6), R6; \
412 BR loopArgs; \
413 tailArgs: /* copy remaining bytes */ \
414 CMP R5, $0; \
415 BEQ callFunction; \
416 SUB $1, R5; \
417 EXRL $callfnMVC<>(SB), R5; \
418 callFunction: \
419 MOVD f+8(FP), R12; \
420 MOVD (R12), R8; \
421 PCDATA $PCDATA_StackMapIndex, $0; \
422 BL (R8); \
423 /* copy return values back */ \
424 MOVD stackArgsType+0(FP), R7; \
425 MOVD stackArgs+16(FP), R6; \
426 MOVWZ stackArgsSize+24(FP), R5; \
427 MOVD $stack-MAXSIZE(SP), R4; \
428 MOVWZ stackRetOffset+28(FP), R1; \
429 ADD R1, R4; \
430 ADD R1, R6; \
431 SUB R1, R5; \
432 BL callRet<>(SB); \
433 RET
434
435 // callRet copies return values back at the end of call*. This is a
436 // separate function so it can allocate stack space for the arguments
437 // to reflectcallmove. It does not follow the Go ABI; it expects its
438 // arguments in registers.
439 TEXT callRet<>(SB), NOSPLIT, $40-0
440 MOVD R7, 8(R15)
441 MOVD R6, 16(R15)
442 MOVD R4, 24(R15)
443 MOVD R5, 32(R15)
444 MOVD $0, 40(R15)
445 BL runtime·reflectcallmove(SB)
446 RET
447
448 CALLFN(·call16, 16)
449 CALLFN(·call32, 32)
450 CALLFN(·call64, 64)
451 CALLFN(·call128, 128)
452 CALLFN(·call256, 256)
453 CALLFN(·call512, 512)
454 CALLFN(·call1024, 1024)
455 CALLFN(·call2048, 2048)
456 CALLFN(·call4096, 4096)
457 CALLFN(·call8192, 8192)
458 CALLFN(·call16384, 16384)
459 CALLFN(·call32768, 32768)
460 CALLFN(·call65536, 65536)
461 CALLFN(·call131072, 131072)
462 CALLFN(·call262144, 262144)
463 CALLFN(·call524288, 524288)
464 CALLFN(·call1048576, 1048576)
465 CALLFN(·call2097152, 2097152)
466 CALLFN(·call4194304, 4194304)
467 CALLFN(·call8388608, 8388608)
468 CALLFN(·call16777216, 16777216)
469 CALLFN(·call33554432, 33554432)
470 CALLFN(·call67108864, 67108864)
471 CALLFN(·call134217728, 134217728)
472 CALLFN(·call268435456, 268435456)
473 CALLFN(·call536870912, 536870912)
474 CALLFN(·call1073741824, 1073741824)
475
476 // Not a function: target for EXRL (execute relative long) instruction.
477 TEXT callfnMVC<>(SB),NOSPLIT|NOFRAME,$0-0
478 MVC $1, 0(R4), 0(R6)
479
480 TEXT runtime·procyield(SB),NOSPLIT,$0-0
481 RET
482
483 // Save state of caller into g->sched,
484 // but using fake PC from systemstack_switch.
485 // Must only be called from functions with no locals ($0)
486 // or else unwinding from systemstack_switch is incorrect.
487 // Smashes R1.
488 TEXT gosave_systemstack_switch<>(SB),NOSPLIT|NOFRAME,$0
489 MOVD $runtime·systemstack_switch(SB), R1
490 ADD $16, R1 // get past prologue
491 MOVD R1, (g_sched+gobuf_pc)(g)
492 MOVD R15, (g_sched+gobuf_sp)(g)
493 MOVD $0, (g_sched+gobuf_lr)(g)
494 MOVD $0, (g_sched+gobuf_ret)(g)
495 // Assert ctxt is zero. See func save.
496 MOVD (g_sched+gobuf_ctxt)(g), R1
497 CMPBEQ R1, $0, 2(PC)
498 BL runtime·abort(SB)
499 RET
500
501 // func asmcgocall(fn, arg unsafe.Pointer) int32
502 // Call fn(arg) on the scheduler stack,
503 // aligned appropriately for the gcc ABI.
504 // See cgocall.go for more details.
505 TEXT ·asmcgocall(SB),NOSPLIT,$0-20
506 // R2 = argc; R3 = argv; R11 = temp; R13 = g; R15 = stack pointer
507 // C TLS base pointer in AR0:AR1
508 MOVD fn+0(FP), R3
509 MOVD arg+8(FP), R4
510
511 MOVD R15, R2 // save original stack pointer
512 MOVD g, R5
513
514 // Figure out if we need to switch to m->g0 stack.
515 // We get called to create new OS threads too, and those
516 // come in on the m->g0 stack already. Or we might already
517 // be on the m->gsignal stack.
518 MOVD g_m(g), R6
519 MOVD m_gsignal(R6), R7
520 CMPBEQ R7, g, g0
521 MOVD m_g0(R6), R7
522 CMPBEQ R7, g, g0
523 BL gosave_systemstack_switch<>(SB)
524 MOVD R7, g
525 BL runtime·save_g(SB)
526 MOVD (g_sched+gobuf_sp)(g), R15
527
528 // Now on a scheduling stack (a pthread-created stack).
529 g0:
530 // Save room for two of our pointers, plus 160 bytes of callee
531 // save area that lives on the caller stack.
532 SUB $176, R15
533 MOVD $~7, R6
534 AND R6, R15 // 8-byte alignment for gcc ABI
535 MOVD R5, 168(R15) // save old g on stack
536 MOVD (g_stack+stack_hi)(R5), R5
537 SUB R2, R5
538 MOVD R5, 160(R15) // save depth in old g stack (can't just save SP, as stack might be copied during a callback)
539 MOVD $0, 0(R15) // clear back chain pointer (TODO can we give it real back trace information?)
540 MOVD R4, R2 // arg in R2
541 BL R3 // can clobber: R0-R5, R14, F0-F3, F5, F7-F15
542
543 XOR R0, R0 // set R0 back to 0.
544 // Restore g, stack pointer.
545 MOVD 168(R15), g
546 BL runtime·save_g(SB)
547 MOVD (g_stack+stack_hi)(g), R5
548 MOVD 160(R15), R6
549 SUB R6, R5
550 MOVD R5, R15
551
552 MOVW R2, ret+16(FP)
553 RET
554
555 // cgocallback(fn, frame unsafe.Pointer, ctxt uintptr)
556 // See cgocall.go for more details.
557 TEXT ·cgocallback(SB),NOSPLIT,$24-24
558 NO_LOCAL_POINTERS
559
560 // Load m and g from thread-local storage.
561 MOVB runtime·iscgo(SB), R3
562 CMPBEQ R3, $0, nocgo
563 BL runtime·load_g(SB)
564
565 nocgo:
566 // If g is nil, Go did not create the current thread.
567 // Call needm to obtain one for temporary use.
568 // In this case, we're running on the thread stack, so there's
569 // lots of space, but the linker doesn't know. Hide the call from
570 // the linker analysis by using an indirect call.
571 CMPBEQ g, $0, needm
572
573 MOVD g_m(g), R8
574 MOVD R8, savedm-8(SP)
575 BR havem
576
577 needm:
578 MOVD g, savedm-8(SP) // g is zero, so is m.
579 MOVD $runtime·needm(SB), R3
580 BL (R3)
581
582 // Set m->sched.sp = SP, so that if a panic happens
583 // during the function we are about to execute, it will
584 // have a valid SP to run on the g0 stack.
585 // The next few lines (after the havem label)
586 // will save this SP onto the stack and then write
587 // the same SP back to m->sched.sp. That seems redundant,
588 // but if an unrecovered panic happens, unwindm will
589 // restore the g->sched.sp from the stack location
590 // and then systemstack will try to use it. If we don't set it here,
591 // that restored SP will be uninitialized (typically 0) and
592 // will not be usable.
593 MOVD g_m(g), R8
594 MOVD m_g0(R8), R3
595 MOVD R15, (g_sched+gobuf_sp)(R3)
596
597 havem:
598 // Now there's a valid m, and we're running on its m->g0.
599 // Save current m->g0->sched.sp on stack and then set it to SP.
600 // Save current sp in m->g0->sched.sp in preparation for
601 // switch back to m->curg stack.
602 // NOTE: unwindm knows that the saved g->sched.sp is at 8(R1) aka savedsp-16(SP).
603 MOVD m_g0(R8), R3
604 MOVD (g_sched+gobuf_sp)(R3), R4
605 MOVD R4, savedsp-24(SP) // must match frame size
606 MOVD R15, (g_sched+gobuf_sp)(R3)
607
608 // Switch to m->curg stack and call runtime.cgocallbackg.
609 // Because we are taking over the execution of m->curg
610 // but *not* resuming what had been running, we need to
611 // save that information (m->curg->sched) so we can restore it.
612 // We can restore m->curg->sched.sp easily, because calling
613 // runtime.cgocallbackg leaves SP unchanged upon return.
614 // To save m->curg->sched.pc, we push it onto the curg stack and
615 // open a frame the same size as cgocallback's g0 frame.
616 // Once we switch to the curg stack, the pushed PC will appear
617 // to be the return PC of cgocallback, so that the traceback
618 // will seamlessly trace back into the earlier calls.
619 MOVD m_curg(R8), g
620 BL runtime·save_g(SB)
621 MOVD (g_sched+gobuf_sp)(g), R4 // prepare stack as R4
622 MOVD (g_sched+gobuf_pc)(g), R5
623 MOVD R5, -(24+8)(R4) // "saved LR"; must match frame size
624 // Gather our arguments into registers.
625 MOVD fn+0(FP), R1
626 MOVD frame+8(FP), R2
627 MOVD ctxt+16(FP), R3
628 MOVD $-(24+8)(R4), R15 // switch stack; must match frame size
629 MOVD R1, 8(R15)
630 MOVD R2, 16(R15)
631 MOVD R3, 24(R15)
632 BL runtime·cgocallbackg(SB)
633
634 // Restore g->sched (== m->curg->sched) from saved values.
635 MOVD 0(R15), R5
636 MOVD R5, (g_sched+gobuf_pc)(g)
637 MOVD $(24+8)(R15), R4 // must match frame size
638 MOVD R4, (g_sched+gobuf_sp)(g)
639
640 // Switch back to m->g0's stack and restore m->g0->sched.sp.
641 // (Unlike m->curg, the g0 goroutine never uses sched.pc,
642 // so we do not have to restore it.)
643 MOVD g_m(g), R8
644 MOVD m_g0(R8), g
645 BL runtime·save_g(SB)
646 MOVD (g_sched+gobuf_sp)(g), R15
647 MOVD savedsp-24(SP), R4 // must match frame size
648 MOVD R4, (g_sched+gobuf_sp)(g)
649
650 // If the m on entry was nil, we called needm above to borrow an m
651 // for the duration of the call. Since the call is over, return it with dropm.
652 MOVD savedm-8(SP), R6
653 CMPBNE R6, $0, droppedm
654 MOVD $runtime·dropm(SB), R3
655 BL (R3)
656 droppedm:
657
658 // Done!
659 RET
660
661 // void setg(G*); set g. for use by needm.
662 TEXT runtime·setg(SB), NOSPLIT, $0-8
663 MOVD gg+0(FP), g
664 // This only happens if iscgo, so jump straight to save_g
665 BL runtime·save_g(SB)
666 RET
667
668 // void setg_gcc(G*); set g in C TLS.
669 // Must obey the gcc calling convention.
670 TEXT setg_gcc<>(SB),NOSPLIT|NOFRAME,$0-0
671 // The standard prologue clobbers LR (R14), which is callee-save in
672 // the C ABI, so we have to use NOFRAME and save LR ourselves.
673 MOVD LR, R1
674 // Also save g, R10, and R11 since they're callee-save in C ABI
675 MOVD R10, R3
676 MOVD g, R4
677 MOVD R11, R5
678
679 MOVD R2, g
680 BL runtime·save_g(SB)
681
682 MOVD R5, R11
683 MOVD R4, g
684 MOVD R3, R10
685 MOVD R1, LR
686 RET
687
688 TEXT runtime·abort(SB),NOSPLIT|NOFRAME,$0-0
689 MOVW (R0), R0
690 UNDEF
691
692 // int64 runtime·cputicks(void)
693 TEXT runtime·cputicks(SB),NOSPLIT,$0-8
694 // The TOD clock on s390 counts from the year 1900 in ~250ps intervals.
695 // This means that since about 1972 the msb has been set, making the
696 // result of a call to STORE CLOCK (stck) a negative number.
697 // We clear the msb to make it positive.
698 STCK ret+0(FP) // serialises before and after call
699 MOVD ret+0(FP), R3 // R3 will wrap to 0 in the year 2043
700 SLD $1, R3
701 SRD $1, R3
702 MOVD R3, ret+0(FP)
703 RET
704
705 // AES hashing not implemented for s390x
706 TEXT runtime·memhash(SB),NOSPLIT|NOFRAME,$0-32
707 JMP runtime·memhashFallback(SB)
708 TEXT runtime·strhash(SB),NOSPLIT|NOFRAME,$0-24
709 JMP runtime·strhashFallback(SB)
710 TEXT runtime·memhash32(SB),NOSPLIT|NOFRAME,$0-24
711 JMP runtime·memhash32Fallback(SB)
712 TEXT runtime·memhash64(SB),NOSPLIT|NOFRAME,$0-24
713 JMP runtime·memhash64Fallback(SB)
714
715 TEXT runtime·return0(SB), NOSPLIT, $0
716 MOVW $0, R3
717 RET
718
719 // Called from cgo wrappers, this function returns g->m->curg.stack.hi.
720 // Must obey the gcc calling convention.
721 TEXT _cgo_topofstack(SB),NOSPLIT|NOFRAME,$0
722 // g (R13), R10, R11 and LR (R14) are callee-save in the C ABI, so save them
723 MOVD g, R1
724 MOVD R10, R3
725 MOVD LR, R4
726 MOVD R11, R5
727
728 BL runtime·load_g(SB) // clobbers g (R13), R10, R11
729 MOVD g_m(g), R2
730 MOVD m_curg(R2), R2
731 MOVD (g_stack+stack_hi)(R2), R2
732
733 MOVD R1, g
734 MOVD R3, R10
735 MOVD R4, LR
736 MOVD R5, R11
737 RET
738
739 // The top-most function running on a goroutine
740 // returns to goexit+PCQuantum.
741 TEXT runtime·goexit(SB),NOSPLIT|NOFRAME|TOPFRAME,$0-0
742 BYTE $0x07; BYTE $0x00; // 2-byte nop
743 BL runtime·goexit1(SB) // does not return
744 // traceback from goexit1 must hit code range of goexit
745 BYTE $0x07; BYTE $0x00; // 2-byte nop
746
747 TEXT ·publicationBarrier(SB),NOSPLIT|NOFRAME,$0-0
748 // Stores are already ordered on s390x, so this is just a
749 // compile barrier.
750 RET
751
752 // This is called from .init_array and follows the platform, not Go, ABI.
753 // We are overly conservative. We could only save the registers we use.
754 // However, since this function is only called once per loaded module
755 // performance is unimportant.
756 TEXT runtime·addmoduledata(SB),NOSPLIT|NOFRAME,$0-0
757 // Save R6-R15 in the register save area of the calling function.
758 // Don't bother saving F8-F15 as we aren't doing any calls.
759 STMG R6, R15, 48(R15)
760
761 // append the argument (passed in R2, as per the ELF ABI) to the
762 // moduledata linked list.
763 MOVD runtime·lastmoduledatap(SB), R1
764 MOVD R2, moduledata_next(R1)
765 MOVD R2, runtime·lastmoduledatap(SB)
766
767 // Restore R6-R15.
768 LMG 48(R15), R6, R15
769 RET
770
771 TEXT ·checkASM(SB),NOSPLIT,$0-1
772 MOVB $1, ret+0(FP)
773 RET
774
775 // gcWriteBarrier performs a heap pointer write and informs the GC.
776 //
777 // gcWriteBarrier does NOT follow the Go ABI. It takes two arguments:
778 // - R2 is the destination of the write
779 // - R3 is the value being written at R2.
780 // It clobbers R10 (the temp register) and R1 (used by PLT stub).
781 // It does not clobber any other general-purpose registers,
782 // but may clobber others (e.g., floating point registers).
783 TEXT runtime·gcWriteBarrier(SB),NOSPLIT,$96
784 // Save the registers clobbered by the fast path.
785 MOVD R4, 96(R15)
786 MOVD g_m(g), R1
787 MOVD m_p(R1), R1
788 // Increment wbBuf.next position.
789 MOVD $16, R4
790 ADD (p_wbBuf+wbBuf_next)(R1), R4
791 MOVD R4, (p_wbBuf+wbBuf_next)(R1)
792 MOVD (p_wbBuf+wbBuf_end)(R1), R1
793 // Record the write.
794 MOVD R3, -16(R4) // Record value
795 MOVD (R2), R10 // TODO: This turns bad writes into bad reads.
796 MOVD R10, -8(R4) // Record *slot
797 // Is the buffer full?
798 CMPBEQ R4, R1, flush
799 ret:
800 MOVD 96(R15), R4
801 // Do the write.
802 MOVD R3, (R2)
803 RET
804
805 flush:
806 // Save all general purpose registers since these could be
807 // clobbered by wbBufFlush and were not saved by the caller.
808 STMG R2, R3, 8(R15) // set R2 and R3 as arguments for wbBufFlush
809 MOVD R0, 24(R15)
810 // R1 already saved.
811 // R4 already saved.
812 STMG R5, R12, 32(R15) // save R5 - R12
813 // R13 is g.
814 // R14 is LR.
815 // R15 is SP.
816
817 // This takes arguments R2 and R3.
818 CALL runtime·wbBufFlush(SB)
819
820 LMG 8(R15), R2, R3 // restore R2 - R3
821 MOVD 24(R15), R0 // restore R0
822 LMG 32(R15), R5, R12 // restore R5 - R12
823 JMP ret
824
825 // Note: these functions use a special calling convention to save generated code space.
826 // Arguments are passed in registers, but the space for those arguments are allocated
827 // in the caller's stack frame. These stubs write the args into that stack space and
828 // then tail call to the corresponding runtime handler.
829 // The tail call makes these stubs disappear in backtraces.
830 TEXT runtime·panicIndex(SB),NOSPLIT,$0-16
831 MOVD R0, x+0(FP)
832 MOVD R1, y+8(FP)
833 JMP runtime·goPanicIndex(SB)
834 TEXT runtime·panicIndexU(SB),NOSPLIT,$0-16
835 MOVD R0, x+0(FP)
836 MOVD R1, y+8(FP)
837 JMP runtime·goPanicIndexU(SB)
838 TEXT runtime·panicSliceAlen(SB),NOSPLIT,$0-16
839 MOVD R1, x+0(FP)
840 MOVD R2, y+8(FP)
841 JMP runtime·goPanicSliceAlen(SB)
842 TEXT runtime·panicSliceAlenU(SB),NOSPLIT,$0-16
843 MOVD R1, x+0(FP)
844 MOVD R2, y+8(FP)
845 JMP runtime·goPanicSliceAlenU(SB)
846 TEXT runtime·panicSliceAcap(SB),NOSPLIT,$0-16
847 MOVD R1, x+0(FP)
848 MOVD R2, y+8(FP)
849 JMP runtime·goPanicSliceAcap(SB)
850 TEXT runtime·panicSliceAcapU(SB),NOSPLIT,$0-16
851 MOVD R1, x+0(FP)
852 MOVD R2, y+8(FP)
853 JMP runtime·goPanicSliceAcapU(SB)
854 TEXT runtime·panicSliceB(SB),NOSPLIT,$0-16
855 MOVD R0, x+0(FP)
856 MOVD R1, y+8(FP)
857 JMP runtime·goPanicSliceB(SB)
858 TEXT runtime·panicSliceBU(SB),NOSPLIT,$0-16
859 MOVD R0, x+0(FP)
860 MOVD R1, y+8(FP)
861 JMP runtime·goPanicSliceBU(SB)
862 TEXT runtime·panicSlice3Alen(SB),NOSPLIT,$0-16
863 MOVD R2, x+0(FP)
864 MOVD R3, y+8(FP)
865 JMP runtime·goPanicSlice3Alen(SB)
866 TEXT runtime·panicSlice3AlenU(SB),NOSPLIT,$0-16
867 MOVD R2, x+0(FP)
868 MOVD R3, y+8(FP)
869 JMP runtime·goPanicSlice3AlenU(SB)
870 TEXT runtime·panicSlice3Acap(SB),NOSPLIT,$0-16
871 MOVD R2, x+0(FP)
872 MOVD R3, y+8(FP)
873 JMP runtime·goPanicSlice3Acap(SB)
874 TEXT runtime·panicSlice3AcapU(SB),NOSPLIT,$0-16
875 MOVD R2, x+0(FP)
876 MOVD R3, y+8(FP)
877 JMP runtime·goPanicSlice3AcapU(SB)
878 TEXT runtime·panicSlice3B(SB),NOSPLIT,$0-16
879 MOVD R1, x+0(FP)
880 MOVD R2, y+8(FP)
881 JMP runtime·goPanicSlice3B(SB)
882 TEXT runtime·panicSlice3BU(SB),NOSPLIT,$0-16
883 MOVD R1, x+0(FP)
884 MOVD R2, y+8(FP)
885 JMP runtime·goPanicSlice3BU(SB)
886 TEXT runtime·panicSlice3C(SB),NOSPLIT,$0-16
887 MOVD R0, x+0(FP)
888 MOVD R1, y+8(FP)
889 JMP runtime·goPanicSlice3C(SB)
890 TEXT runtime·panicSlice3CU(SB),NOSPLIT,$0-16
891 MOVD R0, x+0(FP)
892 MOVD R1, y+8(FP)
893 JMP runtime·goPanicSlice3CU(SB)
894 TEXT runtime·panicSliceConvert(SB),NOSPLIT,$0-16
895 MOVD R2, x+0(FP)
896 MOVD R3, y+8(FP)
897 JMP runtime·goPanicSliceConvert(SB)
898
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