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. 16TEXT _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 50nocgo: 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 58restore: 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. 76TEXT _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 82DATA _rt0_s390x_lib_argc<>(SB)/8, $0 83GLOBL _rt0_s390x_lib_argc<>(SB), NOPTR, $8 84DATA _rt0_s90x_lib_argv<>(SB)/8, $0 85GLOBL _rt0_s390x_lib_argv<>(SB), NOPTR, $8 86 87TEXT runtime·rt0_go(SB),NOSPLIT,$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 126nocgo: 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 $24, R15 151 MOVD R2, 16(R15) 152 MOVD $0, 8(R15) 153 MOVD $0, 0(R15) 154 BL runtime·newproc(SB) 155 ADD $24, R15 156 157 // start this M 158 BL runtime·mstart(SB) 159 160 MOVD $0, 1(R0) 161 RET 162 163DATA runtime·mainPC+0(SB)/8,$runtime·main(SB) 164GLOBL runtime·mainPC(SB),RODATA,$8 165 166TEXT runtime·breakpoint(SB),NOSPLIT|NOFRAME,$0-0 167 MOVD $0, 2(R0) 168 RET 169 170TEXT runtime·asminit(SB),NOSPLIT|NOFRAME,$0-0 171 RET 172 173/* 174 * go-routine 175 */ 176 177// void gosave(Gobuf*) 178// save state in Gobuf; setjmp 179TEXT runtime·gosave(SB), NOSPLIT, $-8-8 180 MOVD buf+0(FP), R3 181 MOVD R15, gobuf_sp(R3) 182 MOVD LR, gobuf_pc(R3) 183 MOVD g, gobuf_g(R3) 184 MOVD $0, gobuf_lr(R3) 185 MOVD $0, gobuf_ret(R3) 186 // Assert ctxt is zero. See func save. 187 MOVD gobuf_ctxt(R3), R3 188 CMPBEQ R3, $0, 2(PC) 189 BL runtime·badctxt(SB) 190 RET 191 192// void gogo(Gobuf*) 193// restore state from Gobuf; longjmp 194TEXT runtime·gogo(SB), NOSPLIT, $16-8 195 MOVD buf+0(FP), R5 196 MOVD gobuf_g(R5), g // make sure g is not nil 197 BL runtime·save_g(SB) 198 199 MOVD 0(g), R4 200 MOVD gobuf_sp(R5), R15 201 MOVD gobuf_lr(R5), LR 202 MOVD gobuf_ret(R5), R3 203 MOVD gobuf_ctxt(R5), R12 204 MOVD $0, gobuf_sp(R5) 205 MOVD $0, gobuf_ret(R5) 206 MOVD $0, gobuf_lr(R5) 207 MOVD $0, gobuf_ctxt(R5) 208 CMP R0, R0 // set condition codes for == test, needed by stack split 209 MOVD gobuf_pc(R5), R6 210 BR (R6) 211 212// void mcall(fn func(*g)) 213// Switch to m->g0's stack, call fn(g). 214// Fn must never return. It should gogo(&g->sched) 215// to keep running g. 216TEXT runtime·mcall(SB), NOSPLIT, $-8-8 217 // Save caller state in g->sched 218 MOVD R15, (g_sched+gobuf_sp)(g) 219 MOVD LR, (g_sched+gobuf_pc)(g) 220 MOVD $0, (g_sched+gobuf_lr)(g) 221 MOVD g, (g_sched+gobuf_g)(g) 222 223 // Switch to m->g0 & its stack, call fn. 224 MOVD g, R3 225 MOVD g_m(g), R8 226 MOVD m_g0(R8), g 227 BL runtime·save_g(SB) 228 CMP g, R3 229 BNE 2(PC) 230 BR runtime·badmcall(SB) 231 MOVD fn+0(FP), R12 // context 232 MOVD 0(R12), R4 // code pointer 233 MOVD (g_sched+gobuf_sp)(g), R15 // sp = m->g0->sched.sp 234 SUB $16, R15 235 MOVD R3, 8(R15) 236 MOVD $0, 0(R15) 237 BL (R4) 238 BR runtime·badmcall2(SB) 239 240// systemstack_switch is a dummy routine that systemstack leaves at the bottom 241// of the G stack. We need to distinguish the routine that 242// lives at the bottom of the G stack from the one that lives 243// at the top of the system stack because the one at the top of 244// the system stack terminates the stack walk (see topofstack()). 245TEXT runtime·systemstack_switch(SB), NOSPLIT, $0-0 246 UNDEF 247 BL (LR) // make sure this function is not leaf 248 RET 249 250// func systemstack(fn func()) 251TEXT runtime·systemstack(SB), NOSPLIT, $0-8 252 MOVD fn+0(FP), R3 // R3 = fn 253 MOVD R3, R12 // context 254 MOVD g_m(g), R4 // R4 = m 255 256 MOVD m_gsignal(R4), R5 // R5 = gsignal 257 CMPBEQ g, R5, noswitch 258 259 MOVD m_g0(R4), R5 // R5 = g0 260 CMPBEQ g, R5, noswitch 261 262 MOVD m_curg(R4), R6 263 CMPBEQ g, R6, switch 264 265 // Bad: g is not gsignal, not g0, not curg. What is it? 266 // Hide call from linker nosplit analysis. 267 MOVD $runtime·badsystemstack(SB), R3 268 BL (R3) 269 BL runtime·abort(SB) 270 271switch: 272 // save our state in g->sched. Pretend to 273 // be systemstack_switch if the G stack is scanned. 274 MOVD $runtime·systemstack_switch(SB), R6 275 ADD $16, R6 // get past prologue 276 MOVD R6, (g_sched+gobuf_pc)(g) 277 MOVD R15, (g_sched+gobuf_sp)(g) 278 MOVD $0, (g_sched+gobuf_lr)(g) 279 MOVD g, (g_sched+gobuf_g)(g) 280 281 // switch to g0 282 MOVD R5, g 283 BL runtime·save_g(SB) 284 MOVD (g_sched+gobuf_sp)(g), R3 285 // make it look like mstart called systemstack on g0, to stop traceback 286 SUB $8, R3 287 MOVD $runtime·mstart(SB), R4 288 MOVD R4, 0(R3) 289 MOVD R3, R15 290 291 // call target function 292 MOVD 0(R12), R3 // code pointer 293 BL (R3) 294 295 // switch back to g 296 MOVD g_m(g), R3 297 MOVD m_curg(R3), g 298 BL runtime·save_g(SB) 299 MOVD (g_sched+gobuf_sp)(g), R15 300 MOVD $0, (g_sched+gobuf_sp)(g) 301 RET 302 303noswitch: 304 // already on m stack, just call directly 305 // Using a tail call here cleans up tracebacks since we won't stop 306 // at an intermediate systemstack. 307 MOVD 0(R12), R3 // code pointer 308 MOVD 0(R15), LR // restore LR 309 ADD $8, R15 310 BR (R3) 311 312/* 313 * support for morestack 314 */ 315 316// Called during function prolog when more stack is needed. 317// Caller has already loaded: 318// R3: framesize, R4: argsize, R5: LR 319// 320// The traceback routines see morestack on a g0 as being 321// the top of a stack (for example, morestack calling newstack 322// calling the scheduler calling newm calling gc), so we must 323// record an argument size. For that purpose, it has no arguments. 324TEXT runtime·morestack(SB),NOSPLIT|NOFRAME,$0-0 325 // Cannot grow scheduler stack (m->g0). 326 MOVD g_m(g), R7 327 MOVD m_g0(R7), R8 328 CMPBNE g, R8, 3(PC) 329 BL runtime·badmorestackg0(SB) 330 BL runtime·abort(SB) 331 332 // Cannot grow signal stack (m->gsignal). 333 MOVD m_gsignal(R7), R8 334 CMP g, R8 335 BNE 3(PC) 336 BL runtime·badmorestackgsignal(SB) 337 BL runtime·abort(SB) 338 339 // Called from f. 340 // Set g->sched to context in f. 341 MOVD R15, (g_sched+gobuf_sp)(g) 342 MOVD LR, R8 343 MOVD R8, (g_sched+gobuf_pc)(g) 344 MOVD R5, (g_sched+gobuf_lr)(g) 345 MOVD R12, (g_sched+gobuf_ctxt)(g) 346 347 // Called from f. 348 // Set m->morebuf to f's caller. 349 MOVD R5, (m_morebuf+gobuf_pc)(R7) // f's caller's PC 350 MOVD R15, (m_morebuf+gobuf_sp)(R7) // f's caller's SP 351 MOVD g, (m_morebuf+gobuf_g)(R7) 352 353 // Call newstack on m->g0's stack. 354 MOVD m_g0(R7), g 355 BL runtime·save_g(SB) 356 MOVD (g_sched+gobuf_sp)(g), R15 357 // Create a stack frame on g0 to call newstack. 358 MOVD $0, -8(R15) // Zero saved LR in frame 359 SUB $8, R15 360 BL runtime·newstack(SB) 361 362 // Not reached, but make sure the return PC from the call to newstack 363 // is still in this function, and not the beginning of the next. 364 UNDEF 365 366TEXT runtime·morestack_noctxt(SB),NOSPLIT|NOFRAME,$0-0 367 MOVD $0, R12 368 BR runtime·morestack(SB) 369 370// reflectcall: call a function with the given argument list 371// func call(argtype *_type, f *FuncVal, arg *byte, argsize, retoffset uint32). 372// we don't have variable-sized frames, so we use a small number 373// of constant-sized-frame functions to encode a few bits of size in the pc. 374// Caution: ugly multiline assembly macros in your future! 375 376#define DISPATCH(NAME,MAXSIZE) \ 377 MOVD $MAXSIZE, R4; \ 378 CMP R3, R4; \ 379 BGT 3(PC); \ 380 MOVD $NAME(SB), R5; \ 381 BR (R5) 382// Note: can't just "BR NAME(SB)" - bad inlining results. 383 384TEXT ·reflectcall(SB), NOSPLIT, $-8-32 385 MOVWZ argsize+24(FP), R3 386 DISPATCH(runtime·call32, 32) 387 DISPATCH(runtime·call64, 64) 388 DISPATCH(runtime·call128, 128) 389 DISPATCH(runtime·call256, 256) 390 DISPATCH(runtime·call512, 512) 391 DISPATCH(runtime·call1024, 1024) 392 DISPATCH(runtime·call2048, 2048) 393 DISPATCH(runtime·call4096, 4096) 394 DISPATCH(runtime·call8192, 8192) 395 DISPATCH(runtime·call16384, 16384) 396 DISPATCH(runtime·call32768, 32768) 397 DISPATCH(runtime·call65536, 65536) 398 DISPATCH(runtime·call131072, 131072) 399 DISPATCH(runtime·call262144, 262144) 400 DISPATCH(runtime·call524288, 524288) 401 DISPATCH(runtime·call1048576, 1048576) 402 DISPATCH(runtime·call2097152, 2097152) 403 DISPATCH(runtime·call4194304, 4194304) 404 DISPATCH(runtime·call8388608, 8388608) 405 DISPATCH(runtime·call16777216, 16777216) 406 DISPATCH(runtime·call33554432, 33554432) 407 DISPATCH(runtime·call67108864, 67108864) 408 DISPATCH(runtime·call134217728, 134217728) 409 DISPATCH(runtime·call268435456, 268435456) 410 DISPATCH(runtime·call536870912, 536870912) 411 DISPATCH(runtime·call1073741824, 1073741824) 412 MOVD $runtime·badreflectcall(SB), R5 413 BR (R5) 414 415#define CALLFN(NAME,MAXSIZE) \ 416TEXT NAME(SB), WRAPPER, $MAXSIZE-24; \ 417 NO_LOCAL_POINTERS; \ 418 /* copy arguments to stack */ \ 419 MOVD arg+16(FP), R4; \ 420 MOVWZ argsize+24(FP), R5; \ 421 MOVD $stack-MAXSIZE(SP), R6; \ 422loopArgs: /* copy 256 bytes at a time */ \ 423 CMP R5, $256; \ 424 BLT tailArgs; \ 425 SUB $256, R5; \ 426 MVC $256, 0(R4), 0(R6); \ 427 MOVD $256(R4), R4; \ 428 MOVD $256(R6), R6; \ 429 BR loopArgs; \ 430tailArgs: /* copy remaining bytes */ \ 431 CMP R5, $0; \ 432 BEQ callFunction; \ 433 SUB $1, R5; \ 434 EXRL $callfnMVC<>(SB), R5; \ 435callFunction: \ 436 MOVD f+8(FP), R12; \ 437 MOVD (R12), R8; \ 438 PCDATA $PCDATA_StackMapIndex, $0; \ 439 BL (R8); \ 440 /* copy return values back */ \ 441 MOVD argtype+0(FP), R7; \ 442 MOVD arg+16(FP), R6; \ 443 MOVWZ n+24(FP), R5; \ 444 MOVD $stack-MAXSIZE(SP), R4; \ 445 MOVWZ retoffset+28(FP), R1; \ 446 ADD R1, R4; \ 447 ADD R1, R6; \ 448 SUB R1, R5; \ 449 BL callRet<>(SB); \ 450 RET 451 452// callRet copies return values back at the end of call*. This is a 453// separate function so it can allocate stack space for the arguments 454// to reflectcallmove. It does not follow the Go ABI; it expects its 455// arguments in registers. 456TEXT callRet<>(SB), NOSPLIT, $32-0 457 MOVD R7, 8(R15) 458 MOVD R6, 16(R15) 459 MOVD R4, 24(R15) 460 MOVD R5, 32(R15) 461 BL runtime·reflectcallmove(SB) 462 RET 463 464CALLFN(·call32, 32) 465CALLFN(·call64, 64) 466CALLFN(·call128, 128) 467CALLFN(·call256, 256) 468CALLFN(·call512, 512) 469CALLFN(·call1024, 1024) 470CALLFN(·call2048, 2048) 471CALLFN(·call4096, 4096) 472CALLFN(·call8192, 8192) 473CALLFN(·call16384, 16384) 474CALLFN(·call32768, 32768) 475CALLFN(·call65536, 65536) 476CALLFN(·call131072, 131072) 477CALLFN(·call262144, 262144) 478CALLFN(·call524288, 524288) 479CALLFN(·call1048576, 1048576) 480CALLFN(·call2097152, 2097152) 481CALLFN(·call4194304, 4194304) 482CALLFN(·call8388608, 8388608) 483CALLFN(·call16777216, 16777216) 484CALLFN(·call33554432, 33554432) 485CALLFN(·call67108864, 67108864) 486CALLFN(·call134217728, 134217728) 487CALLFN(·call268435456, 268435456) 488CALLFN(·call536870912, 536870912) 489CALLFN(·call1073741824, 1073741824) 490 491// Not a function: target for EXRL (execute relative long) instruction. 492TEXT callfnMVC<>(SB),NOSPLIT|NOFRAME,$0-0 493 MVC $1, 0(R4), 0(R6) 494 495TEXT runtime·procyield(SB),NOSPLIT,$0-0 496 RET 497 498// void jmpdefer(fv, sp); 499// called from deferreturn. 500// 1. grab stored LR for caller 501// 2. sub 6 bytes to get back to BL deferreturn (size of BRASL instruction) 502// 3. BR to fn 503TEXT runtime·jmpdefer(SB),NOSPLIT|NOFRAME,$0-16 504 MOVD 0(R15), R1 505 SUB $6, R1, LR 506 507 MOVD fv+0(FP), R12 508 MOVD argp+8(FP), R15 509 SUB $8, R15 510 MOVD 0(R12), R3 511 BR (R3) 512 513// Save state of caller into g->sched. Smashes R1. 514TEXT gosave<>(SB),NOSPLIT|NOFRAME,$0 515 MOVD LR, (g_sched+gobuf_pc)(g) 516 MOVD R15, (g_sched+gobuf_sp)(g) 517 MOVD $0, (g_sched+gobuf_lr)(g) 518 MOVD $0, (g_sched+gobuf_ret)(g) 519 // Assert ctxt is zero. See func save. 520 MOVD (g_sched+gobuf_ctxt)(g), R1 521 CMPBEQ R1, $0, 2(PC) 522 BL runtime·badctxt(SB) 523 RET 524 525// func asmcgocall(fn, arg unsafe.Pointer) int32 526// Call fn(arg) on the scheduler stack, 527// aligned appropriately for the gcc ABI. 528// See cgocall.go for more details. 529TEXT ·asmcgocall(SB),NOSPLIT,$0-20 530 // R2 = argc; R3 = argv; R11 = temp; R13 = g; R15 = stack pointer 531 // C TLS base pointer in AR0:AR1 532 MOVD fn+0(FP), R3 533 MOVD arg+8(FP), R4 534 535 MOVD R15, R2 // save original stack pointer 536 MOVD g, R5 537 538 // Figure out if we need to switch to m->g0 stack. 539 // We get called to create new OS threads too, and those 540 // come in on the m->g0 stack already. 541 MOVD g_m(g), R6 542 MOVD m_g0(R6), R6 543 CMPBEQ R6, g, g0 544 BL gosave<>(SB) 545 MOVD R6, g 546 BL runtime·save_g(SB) 547 MOVD (g_sched+gobuf_sp)(g), R15 548 549 // Now on a scheduling stack (a pthread-created stack). 550g0: 551 // Save room for two of our pointers, plus 160 bytes of callee 552 // save area that lives on the caller stack. 553 SUB $176, R15 554 MOVD $~7, R6 555 AND R6, R15 // 8-byte alignment for gcc ABI 556 MOVD R5, 168(R15) // save old g on stack 557 MOVD (g_stack+stack_hi)(R5), R5 558 SUB R2, R5 559 MOVD R5, 160(R15) // save depth in old g stack (can't just save SP, as stack might be copied during a callback) 560 MOVD $0, 0(R15) // clear back chain pointer (TODO can we give it real back trace information?) 561 MOVD R4, R2 // arg in R2 562 BL R3 // can clobber: R0-R5, R14, F0-F3, F5, F7-F15 563 564 XOR R0, R0 // set R0 back to 0. 565 // Restore g, stack pointer. 566 MOVD 168(R15), g 567 BL runtime·save_g(SB) 568 MOVD (g_stack+stack_hi)(g), R5 569 MOVD 160(R15), R6 570 SUB R6, R5 571 MOVD R5, R15 572 573 MOVW R2, ret+16(FP) 574 RET 575 576// cgocallback(void (*fn)(void*), void *frame, uintptr framesize, uintptr ctxt) 577// Turn the fn into a Go func (by taking its address) and call 578// cgocallback_gofunc. 579TEXT runtime·cgocallback(SB),NOSPLIT,$32-32 580 MOVD $fn+0(FP), R3 581 MOVD R3, 8(R15) 582 MOVD frame+8(FP), R3 583 MOVD R3, 16(R15) 584 MOVD framesize+16(FP), R3 585 MOVD R3, 24(R15) 586 MOVD ctxt+24(FP), R3 587 MOVD R3, 32(R15) 588 MOVD $runtime·cgocallback_gofunc(SB), R3 589 BL (R3) 590 RET 591 592// cgocallback_gofunc(FuncVal*, void *frame, uintptr framesize, uintptr ctxt) 593// See cgocall.go for more details. 594TEXT ·cgocallback_gofunc(SB),NOSPLIT,$16-32 595 NO_LOCAL_POINTERS 596 597 // Load m and g from thread-local storage. 598 MOVB runtime·iscgo(SB), R3 599 CMPBEQ R3, $0, nocgo 600 BL runtime·load_g(SB) 601 602nocgo: 603 // If g is nil, Go did not create the current thread. 604 // Call needm to obtain one for temporary use. 605 // In this case, we're running on the thread stack, so there's 606 // lots of space, but the linker doesn't know. Hide the call from 607 // the linker analysis by using an indirect call. 608 CMPBEQ g, $0, needm 609 610 MOVD g_m(g), R8 611 MOVD R8, savedm-8(SP) 612 BR havem 613 614needm: 615 MOVD g, savedm-8(SP) // g is zero, so is m. 616 MOVD $runtime·needm(SB), R3 617 BL (R3) 618 619 // Set m->sched.sp = SP, so that if a panic happens 620 // during the function we are about to execute, it will 621 // have a valid SP to run on the g0 stack. 622 // The next few lines (after the havem label) 623 // will save this SP onto the stack and then write 624 // the same SP back to m->sched.sp. That seems redundant, 625 // but if an unrecovered panic happens, unwindm will 626 // restore the g->sched.sp from the stack location 627 // and then systemstack will try to use it. If we don't set it here, 628 // that restored SP will be uninitialized (typically 0) and 629 // will not be usable. 630 MOVD g_m(g), R8 631 MOVD m_g0(R8), R3 632 MOVD R15, (g_sched+gobuf_sp)(R3) 633 634havem: 635 // Now there's a valid m, and we're running on its m->g0. 636 // Save current m->g0->sched.sp on stack and then set it to SP. 637 // Save current sp in m->g0->sched.sp in preparation for 638 // switch back to m->curg stack. 639 // NOTE: unwindm knows that the saved g->sched.sp is at 8(R1) aka savedsp-16(SP). 640 MOVD m_g0(R8), R3 641 MOVD (g_sched+gobuf_sp)(R3), R4 642 MOVD R4, savedsp-16(SP) 643 MOVD R15, (g_sched+gobuf_sp)(R3) 644 645 // Switch to m->curg stack and call runtime.cgocallbackg. 646 // Because we are taking over the execution of m->curg 647 // but *not* resuming what had been running, we need to 648 // save that information (m->curg->sched) so we can restore it. 649 // We can restore m->curg->sched.sp easily, because calling 650 // runtime.cgocallbackg leaves SP unchanged upon return. 651 // To save m->curg->sched.pc, we push it onto the stack. 652 // This has the added benefit that it looks to the traceback 653 // routine like cgocallbackg is going to return to that 654 // PC (because the frame we allocate below has the same 655 // size as cgocallback_gofunc's frame declared above) 656 // so that the traceback will seamlessly trace back into 657 // the earlier calls. 658 // 659 // In the new goroutine, -8(SP) is unused (where SP refers to 660 // m->curg's SP while we're setting it up, before we've adjusted it). 661 MOVD m_curg(R8), g 662 BL runtime·save_g(SB) 663 MOVD (g_sched+gobuf_sp)(g), R4 // prepare stack as R4 664 MOVD (g_sched+gobuf_pc)(g), R5 665 MOVD R5, -24(R4) 666 MOVD ctxt+24(FP), R5 667 MOVD R5, -16(R4) 668 MOVD $-24(R4), R15 669 BL runtime·cgocallbackg(SB) 670 671 // Restore g->sched (== m->curg->sched) from saved values. 672 MOVD 0(R15), R5 673 MOVD R5, (g_sched+gobuf_pc)(g) 674 MOVD $24(R15), R4 675 MOVD R4, (g_sched+gobuf_sp)(g) 676 677 // Switch back to m->g0's stack and restore m->g0->sched.sp. 678 // (Unlike m->curg, the g0 goroutine never uses sched.pc, 679 // so we do not have to restore it.) 680 MOVD g_m(g), R8 681 MOVD m_g0(R8), g 682 BL runtime·save_g(SB) 683 MOVD (g_sched+gobuf_sp)(g), R15 684 MOVD savedsp-16(SP), R4 685 MOVD R4, (g_sched+gobuf_sp)(g) 686 687 // If the m on entry was nil, we called needm above to borrow an m 688 // for the duration of the call. Since the call is over, return it with dropm. 689 MOVD savedm-8(SP), R6 690 CMPBNE R6, $0, droppedm 691 MOVD $runtime·dropm(SB), R3 692 BL (R3) 693droppedm: 694 695 // Done! 696 RET 697 698// void setg(G*); set g. for use by needm. 699TEXT runtime·setg(SB), NOSPLIT, $0-8 700 MOVD gg+0(FP), g 701 // This only happens if iscgo, so jump straight to save_g 702 BL runtime·save_g(SB) 703 RET 704 705// void setg_gcc(G*); set g in C TLS. 706// Must obey the gcc calling convention. 707TEXT setg_gcc<>(SB),NOSPLIT|NOFRAME,$0-0 708 // The standard prologue clobbers LR (R14), which is callee-save in 709 // the C ABI, so we have to use NOFRAME and save LR ourselves. 710 MOVD LR, R1 711 // Also save g, R10, and R11 since they're callee-save in C ABI 712 MOVD R10, R3 713 MOVD g, R4 714 MOVD R11, R5 715 716 MOVD R2, g 717 BL runtime·save_g(SB) 718 719 MOVD R5, R11 720 MOVD R4, g 721 MOVD R3, R10 722 MOVD R1, LR 723 RET 724 725TEXT runtime·abort(SB),NOSPLIT|NOFRAME,$0-0 726 MOVW (R0), R0 727 UNDEF 728 729// int64 runtime·cputicks(void) 730TEXT runtime·cputicks(SB),NOSPLIT,$0-8 731 // The TOD clock on s390 counts from the year 1900 in ~250ps intervals. 732 // This means that since about 1972 the msb has been set, making the 733 // result of a call to STORE CLOCK (stck) a negative number. 734 // We clear the msb to make it positive. 735 STCK ret+0(FP) // serialises before and after call 736 MOVD ret+0(FP), R3 // R3 will wrap to 0 in the year 2043 737 SLD $1, R3 738 SRD $1, R3 739 MOVD R3, ret+0(FP) 740 RET 741 742// AES hashing not implemented for s390x 743TEXT runtime·memhash(SB),NOSPLIT|NOFRAME,$0-32 744 JMP runtime·memhashFallback(SB) 745TEXT runtime·strhash(SB),NOSPLIT|NOFRAME,$0-24 746 JMP runtime·strhashFallback(SB) 747TEXT runtime·memhash32(SB),NOSPLIT|NOFRAME,$0-24 748 JMP runtime·memhash32Fallback(SB) 749TEXT runtime·memhash64(SB),NOSPLIT|NOFRAME,$0-24 750 JMP runtime·memhash64Fallback(SB) 751 752TEXT runtime·return0(SB), NOSPLIT, $0 753 MOVW $0, R3 754 RET 755 756// Called from cgo wrappers, this function returns g->m->curg.stack.hi. 757// Must obey the gcc calling convention. 758TEXT _cgo_topofstack(SB),NOSPLIT|NOFRAME,$0 759 // g (R13), R10, R11 and LR (R14) are callee-save in the C ABI, so save them 760 MOVD g, R1 761 MOVD R10, R3 762 MOVD LR, R4 763 MOVD R11, R5 764 765 BL runtime·load_g(SB) // clobbers g (R13), R10, R11 766 MOVD g_m(g), R2 767 MOVD m_curg(R2), R2 768 MOVD (g_stack+stack_hi)(R2), R2 769 770 MOVD R1, g 771 MOVD R3, R10 772 MOVD R4, LR 773 MOVD R5, R11 774 RET 775 776// The top-most function running on a goroutine 777// returns to goexit+PCQuantum. 778TEXT runtime·goexit(SB),NOSPLIT|NOFRAME|TOPFRAME,$0-0 779 BYTE $0x07; BYTE $0x00; // 2-byte nop 780 BL runtime·goexit1(SB) // does not return 781 // traceback from goexit1 must hit code range of goexit 782 BYTE $0x07; BYTE $0x00; // 2-byte nop 783 784TEXT ·publicationBarrier(SB),NOSPLIT|NOFRAME,$0-0 785 // Stores are already ordered on s390x, so this is just a 786 // compile barrier. 787 RET 788 789// This is called from .init_array and follows the platform, not Go, ABI. 790// We are overly conservative. We could only save the registers we use. 791// However, since this function is only called once per loaded module 792// performance is unimportant. 793TEXT runtime·addmoduledata(SB),NOSPLIT|NOFRAME,$0-0 794 // Save R6-R15 in the register save area of the calling function. 795 // Don't bother saving F8-F15 as we aren't doing any calls. 796 STMG R6, R15, 48(R15) 797 798 // append the argument (passed in R2, as per the ELF ABI) to the 799 // moduledata linked list. 800 MOVD runtime·lastmoduledatap(SB), R1 801 MOVD R2, moduledata_next(R1) 802 MOVD R2, runtime·lastmoduledatap(SB) 803 804 // Restore R6-R15. 805 LMG 48(R15), R6, R15 806 RET 807 808TEXT ·checkASM(SB),NOSPLIT,$0-1 809 MOVB $1, ret+0(FP) 810 RET 811 812// gcWriteBarrier performs a heap pointer write and informs the GC. 813// 814// gcWriteBarrier does NOT follow the Go ABI. It takes two arguments: 815// - R2 is the destination of the write 816// - R3 is the value being written at R2. 817// It clobbers R10 (the temp register). 818// It does not clobber any other general-purpose registers, 819// but may clobber others (e.g., floating point registers). 820TEXT runtime·gcWriteBarrier(SB),NOSPLIT,$104 821 // Save the registers clobbered by the fast path. 822 MOVD R1, 96(R15) 823 MOVD R4, 104(R15) 824 MOVD g_m(g), R1 825 MOVD m_p(R1), R1 826 // Increment wbBuf.next position. 827 MOVD $16, R4 828 ADD (p_wbBuf+wbBuf_next)(R1), R4 829 MOVD R4, (p_wbBuf+wbBuf_next)(R1) 830 MOVD (p_wbBuf+wbBuf_end)(R1), R1 831 // Record the write. 832 MOVD R3, -16(R4) // Record value 833 MOVD (R2), R10 // TODO: This turns bad writes into bad reads. 834 MOVD R10, -8(R4) // Record *slot 835 // Is the buffer full? 836 CMPBEQ R4, R1, flush 837ret: 838 MOVD 96(R15), R1 839 MOVD 104(R15), R4 840 // Do the write. 841 MOVD R3, (R2) 842 RET 843 844flush: 845 // Save all general purpose registers since these could be 846 // clobbered by wbBufFlush and were not saved by the caller. 847 STMG R2, R3, 8(R15) // set R2 and R3 as arguments for wbBufFlush 848 MOVD R0, 24(R15) 849 // R1 already saved. 850 // R4 already saved. 851 STMG R5, R12, 32(R15) // save R5 - R12 852 // R13 is g. 853 // R14 is LR. 854 // R15 is SP. 855 856 // This takes arguments R2 and R3. 857 CALL runtime·wbBufFlush(SB) 858 859 LMG 8(R15), R2, R3 // restore R2 - R3 860 MOVD 24(R15), R0 // restore R0 861 LMG 32(R15), R5, R12 // restore R5 - R12 862 JMP ret 863 864// Note: these functions use a special calling convention to save generated code space. 865// Arguments are passed in registers, but the space for those arguments are allocated 866// in the caller's stack frame. These stubs write the args into that stack space and 867// then tail call to the corresponding runtime handler. 868// The tail call makes these stubs disappear in backtraces. 869TEXT runtime·panicIndex(SB),NOSPLIT,$0-16 870 MOVD R0, x+0(FP) 871 MOVD R1, y+8(FP) 872 JMP runtime·goPanicIndex(SB) 873TEXT runtime·panicIndexU(SB),NOSPLIT,$0-16 874 MOVD R0, x+0(FP) 875 MOVD R1, y+8(FP) 876 JMP runtime·goPanicIndexU(SB) 877TEXT runtime·panicSliceAlen(SB),NOSPLIT,$0-16 878 MOVD R1, x+0(FP) 879 MOVD R2, y+8(FP) 880 JMP runtime·goPanicSliceAlen(SB) 881TEXT runtime·panicSliceAlenU(SB),NOSPLIT,$0-16 882 MOVD R1, x+0(FP) 883 MOVD R2, y+8(FP) 884 JMP runtime·goPanicSliceAlenU(SB) 885TEXT runtime·panicSliceAcap(SB),NOSPLIT,$0-16 886 MOVD R1, x+0(FP) 887 MOVD R2, y+8(FP) 888 JMP runtime·goPanicSliceAcap(SB) 889TEXT runtime·panicSliceAcapU(SB),NOSPLIT,$0-16 890 MOVD R1, x+0(FP) 891 MOVD R2, y+8(FP) 892 JMP runtime·goPanicSliceAcapU(SB) 893TEXT runtime·panicSliceB(SB),NOSPLIT,$0-16 894 MOVD R0, x+0(FP) 895 MOVD R1, y+8(FP) 896 JMP runtime·goPanicSliceB(SB) 897TEXT runtime·panicSliceBU(SB),NOSPLIT,$0-16 898 MOVD R0, x+0(FP) 899 MOVD R1, y+8(FP) 900 JMP runtime·goPanicSliceBU(SB) 901TEXT runtime·panicSlice3Alen(SB),NOSPLIT,$0-16 902 MOVD R2, x+0(FP) 903 MOVD R3, y+8(FP) 904 JMP runtime·goPanicSlice3Alen(SB) 905TEXT runtime·panicSlice3AlenU(SB),NOSPLIT,$0-16 906 MOVD R2, x+0(FP) 907 MOVD R3, y+8(FP) 908 JMP runtime·goPanicSlice3AlenU(SB) 909TEXT runtime·panicSlice3Acap(SB),NOSPLIT,$0-16 910 MOVD R2, x+0(FP) 911 MOVD R3, y+8(FP) 912 JMP runtime·goPanicSlice3Acap(SB) 913TEXT runtime·panicSlice3AcapU(SB),NOSPLIT,$0-16 914 MOVD R2, x+0(FP) 915 MOVD R3, y+8(FP) 916 JMP runtime·goPanicSlice3AcapU(SB) 917TEXT runtime·panicSlice3B(SB),NOSPLIT,$0-16 918 MOVD R1, x+0(FP) 919 MOVD R2, y+8(FP) 920 JMP runtime·goPanicSlice3B(SB) 921TEXT runtime·panicSlice3BU(SB),NOSPLIT,$0-16 922 MOVD R1, x+0(FP) 923 MOVD R2, y+8(FP) 924 JMP runtime·goPanicSlice3BU(SB) 925TEXT runtime·panicSlice3C(SB),NOSPLIT,$0-16 926 MOVD R0, x+0(FP) 927 MOVD R1, y+8(FP) 928 JMP runtime·goPanicSlice3C(SB) 929TEXT runtime·panicSlice3CU(SB),NOSPLIT,$0-16 930 MOVD R0, x+0(FP) 931 MOVD R1, y+8(FP) 932 JMP runtime·goPanicSlice3CU(SB) 933