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 5package runtime 6 7import ( 8 "runtime/internal/atomic" 9 "runtime/internal/sys" 10 "unsafe" 11) 12 13// defined constants 14const ( 15 // G status 16 // 17 // Beyond indicating the general state of a G, the G status 18 // acts like a lock on the goroutine's stack (and hence its 19 // ability to execute user code). 20 // 21 // If you add to this list, add to the list 22 // of "okay during garbage collection" status 23 // in mgcmark.go too. 24 25 // _Gidle means this goroutine was just allocated and has not 26 // yet been initialized. 27 _Gidle = iota // 0 28 29 // _Grunnable means this goroutine is on a run queue. It is 30 // not currently executing user code. The stack is not owned. 31 _Grunnable // 1 32 33 // _Grunning means this goroutine may execute user code. The 34 // stack is owned by this goroutine. It is not on a run queue. 35 // It is assigned an M and a P. 36 _Grunning // 2 37 38 // _Gsyscall means this goroutine is executing a system call. 39 // It is not executing user code. The stack is owned by this 40 // goroutine. It is not on a run queue. It is assigned an M. 41 _Gsyscall // 3 42 43 // _Gwaiting means this goroutine is blocked in the runtime. 44 // It is not executing user code. It is not on a run queue, 45 // but should be recorded somewhere (e.g., a channel wait 46 // queue) so it can be ready()d when necessary. The stack is 47 // not owned *except* that a channel operation may read or 48 // write parts of the stack under the appropriate channel 49 // lock. Otherwise, it is not safe to access the stack after a 50 // goroutine enters _Gwaiting (e.g., it may get moved). 51 _Gwaiting // 4 52 53 // _Gmoribund_unused is currently unused, but hardcoded in gdb 54 // scripts. 55 _Gmoribund_unused // 5 56 57 // _Gdead means this goroutine is currently unused. It may be 58 // just exited, on a free list, or just being initialized. It 59 // is not executing user code. It may or may not have a stack 60 // allocated. The G and its stack (if any) are owned by the M 61 // that is exiting the G or that obtained the G from the free 62 // list. 63 _Gdead // 6 64 65 // _Genqueue_unused is currently unused. 66 _Genqueue_unused // 7 67 68 // _Gcopystack means this goroutine's stack is being moved. It 69 // is not executing user code and is not on a run queue. The 70 // stack is owned by the goroutine that put it in _Gcopystack. 71 _Gcopystack // 8 72 73 // _Gscan combined with one of the above states other than 74 // _Grunning indicates that GC is scanning the stack. The 75 // goroutine is not executing user code and the stack is owned 76 // by the goroutine that set the _Gscan bit. 77 // 78 // _Gscanrunning is different: it is used to briefly block 79 // state transitions while GC signals the G to scan its own 80 // stack. This is otherwise like _Grunning. 81 // 82 // atomicstatus&~Gscan gives the state the goroutine will 83 // return to when the scan completes. 84 _Gscan = 0x1000 85 _Gscanrunnable = _Gscan + _Grunnable // 0x1001 86 _Gscanrunning = _Gscan + _Grunning // 0x1002 87 _Gscansyscall = _Gscan + _Gsyscall // 0x1003 88 _Gscanwaiting = _Gscan + _Gwaiting // 0x1004 89) 90 91const ( 92 // P status 93 _Pidle = iota 94 _Prunning // Only this P is allowed to change from _Prunning. 95 _Psyscall 96 _Pgcstop 97 _Pdead 98) 99 100// Mutual exclusion locks. In the uncontended case, 101// as fast as spin locks (just a few user-level instructions), 102// but on the contention path they sleep in the kernel. 103// A zeroed Mutex is unlocked (no need to initialize each lock). 104type mutex struct { 105 // Futex-based impl treats it as uint32 key, 106 // while sema-based impl as M* waitm. 107 // Used to be a union, but unions break precise GC. 108 key uintptr 109} 110 111// sleep and wakeup on one-time events. 112// before any calls to notesleep or notewakeup, 113// must call noteclear to initialize the Note. 114// then, exactly one thread can call notesleep 115// and exactly one thread can call notewakeup (once). 116// once notewakeup has been called, the notesleep 117// will return. future notesleep will return immediately. 118// subsequent noteclear must be called only after 119// previous notesleep has returned, e.g. it's disallowed 120// to call noteclear straight after notewakeup. 121// 122// notetsleep is like notesleep but wakes up after 123// a given number of nanoseconds even if the event 124// has not yet happened. if a goroutine uses notetsleep to 125// wake up early, it must wait to call noteclear until it 126// can be sure that no other goroutine is calling 127// notewakeup. 128// 129// notesleep/notetsleep are generally called on g0, 130// notetsleepg is similar to notetsleep but is called on user g. 131type note struct { 132 // Futex-based impl treats it as uint32 key, 133 // while sema-based impl as M* waitm. 134 // Used to be a union, but unions break precise GC. 135 key uintptr 136} 137 138type funcval struct { 139 fn uintptr 140 // variable-size, fn-specific data here 141} 142 143// The representation of a non-empty interface. 144// See comment in iface.go for more details on this struct. 145type iface struct { 146 tab unsafe.Pointer 147 data unsafe.Pointer 148} 149 150// The representation of an empty interface. 151// See comment in iface.go for more details on this struct. 152type eface struct { 153 _type *_type 154 data unsafe.Pointer 155} 156 157func efaceOf(ep *interface{}) *eface { 158 return (*eface)(unsafe.Pointer(ep)) 159} 160 161// The guintptr, muintptr, and puintptr are all used to bypass write barriers. 162// It is particularly important to avoid write barriers when the current P has 163// been released, because the GC thinks the world is stopped, and an 164// unexpected write barrier would not be synchronized with the GC, 165// which can lead to a half-executed write barrier that has marked the object 166// but not queued it. If the GC skips the object and completes before the 167// queuing can occur, it will incorrectly free the object. 168// 169// We tried using special assignment functions invoked only when not 170// holding a running P, but then some updates to a particular memory 171// word went through write barriers and some did not. This breaks the 172// write barrier shadow checking mode, and it is also scary: better to have 173// a word that is completely ignored by the GC than to have one for which 174// only a few updates are ignored. 175// 176// Gs and Ps are always reachable via true pointers in the 177// allgs and allp lists or (during allocation before they reach those lists) 178// from stack variables. 179// 180// Ms are always reachable via true pointers either from allm or 181// freem. Unlike Gs and Ps we do free Ms, so it's important that 182// nothing ever hold an muintptr across a safe point. 183 184// A guintptr holds a goroutine pointer, but typed as a uintptr 185// to bypass write barriers. It is used in the Gobuf goroutine state 186// and in scheduling lists that are manipulated without a P. 187// 188// The Gobuf.g goroutine pointer is almost always updated by assembly code. 189// In one of the few places it is updated by Go code - func save - it must be 190// treated as a uintptr to avoid a write barrier being emitted at a bad time. 191// Instead of figuring out how to emit the write barriers missing in the 192// assembly manipulation, we change the type of the field to uintptr, 193// so that it does not require write barriers at all. 194// 195// Goroutine structs are published in the allg list and never freed. 196// That will keep the goroutine structs from being collected. 197// There is never a time that Gobuf.g's contain the only references 198// to a goroutine: the publishing of the goroutine in allg comes first. 199// Goroutine pointers are also kept in non-GC-visible places like TLS, 200// so I can't see them ever moving. If we did want to start moving data 201// in the GC, we'd need to allocate the goroutine structs from an 202// alternate arena. Using guintptr doesn't make that problem any worse. 203type guintptr uintptr 204 205//go:nosplit 206func (gp guintptr) ptr() *g { return (*g)(unsafe.Pointer(gp)) } 207 208//go:nosplit 209func (gp *guintptr) set(g *g) { *gp = guintptr(unsafe.Pointer(g)) } 210 211//go:nosplit 212func (gp *guintptr) cas(old, new guintptr) bool { 213 return atomic.Casuintptr((*uintptr)(unsafe.Pointer(gp)), uintptr(old), uintptr(new)) 214} 215 216// setGNoWB performs *gp = new without a write barrier. 217// For times when it's impractical to use a guintptr. 218//go:nosplit 219//go:nowritebarrier 220func setGNoWB(gp **g, new *g) { 221 (*guintptr)(unsafe.Pointer(gp)).set(new) 222} 223 224type puintptr uintptr 225 226//go:nosplit 227func (pp puintptr) ptr() *p { return (*p)(unsafe.Pointer(pp)) } 228 229//go:nosplit 230func (pp *puintptr) set(p *p) { *pp = puintptr(unsafe.Pointer(p)) } 231 232// muintptr is a *m that is not tracked by the garbage collector. 233// 234// Because we do free Ms, there are some additional constrains on 235// muintptrs: 236// 237// 1. Never hold an muintptr locally across a safe point. 238// 239// 2. Any muintptr in the heap must be owned by the M itself so it can 240// ensure it is not in use when the last true *m is released. 241type muintptr uintptr 242 243//go:nosplit 244func (mp muintptr) ptr() *m { return (*m)(unsafe.Pointer(mp)) } 245 246//go:nosplit 247func (mp *muintptr) set(m *m) { *mp = muintptr(unsafe.Pointer(m)) } 248 249// setMNoWB performs *mp = new without a write barrier. 250// For times when it's impractical to use an muintptr. 251//go:nosplit 252//go:nowritebarrier 253func setMNoWB(mp **m, new *m) { 254 (*muintptr)(unsafe.Pointer(mp)).set(new) 255} 256 257// sudog represents a g in a wait list, such as for sending/receiving 258// on a channel. 259// 260// sudog is necessary because the g ↔ synchronization object relation 261// is many-to-many. A g can be on many wait lists, so there may be 262// many sudogs for one g; and many gs may be waiting on the same 263// synchronization object, so there may be many sudogs for one object. 264// 265// sudogs are allocated from a special pool. Use acquireSudog and 266// releaseSudog to allocate and free them. 267type sudog struct { 268 // The following fields are protected by the hchan.lock of the 269 // channel this sudog is blocking on. shrinkstack depends on 270 // this for sudogs involved in channel ops. 271 272 g *g 273 274 // isSelect indicates g is participating in a select, so 275 // g.selectDone must be CAS'd to win the wake-up race. 276 isSelect bool 277 next *sudog 278 prev *sudog 279 elem unsafe.Pointer // data element (may point to stack) 280 281 // The following fields are never accessed concurrently. 282 // For channels, waitlink is only accessed by g. 283 // For semaphores, all fields (including the ones above) 284 // are only accessed when holding a semaRoot lock. 285 286 acquiretime int64 287 releasetime int64 288 ticket uint32 289 parent *sudog // semaRoot binary tree 290 waitlink *sudog // g.waiting list or semaRoot 291 waittail *sudog // semaRoot 292 c *hchan // channel 293} 294 295/* 296Not used by gccgo. 297 298type libcall struct { 299 fn uintptr 300 n uintptr // number of parameters 301 args uintptr // parameters 302 r1 uintptr // return values 303 r2 uintptr 304 err uintptr // error number 305} 306 307*/ 308 309/* 310Not used by gccgo. 311 312// describes how to handle callback 313type wincallbackcontext struct { 314 gobody unsafe.Pointer // go function to call 315 argsize uintptr // callback arguments size (in bytes) 316 restorestack uintptr // adjust stack on return by (in bytes) (386 only) 317 cleanstack bool 318} 319*/ 320 321/* 322Not used by gccgo. 323 324// Stack describes a Go execution stack. 325// The bounds of the stack are exactly [lo, hi), 326// with no implicit data structures on either side. 327type stack struct { 328 lo uintptr 329 hi uintptr 330} 331*/ 332 333type g struct { 334 // Stack parameters. 335 // stack describes the actual stack memory: [stack.lo, stack.hi). 336 // stackguard0 is the stack pointer compared in the Go stack growth prologue. 337 // It is stack.lo+StackGuard normally, but can be StackPreempt to trigger a preemption. 338 // stackguard1 is the stack pointer compared in the C stack growth prologue. 339 // It is stack.lo+StackGuard on g0 and gsignal stacks. 340 // It is ~0 on other goroutine stacks, to trigger a call to morestackc (and crash). 341 // Not for gccgo: stack stack // offset known to runtime/cgo 342 // Not for gccgo: stackguard0 uintptr // offset known to liblink 343 // Not for gccgo: stackguard1 uintptr // offset known to liblink 344 345 _panic *_panic // innermost panic - offset known to liblink 346 _defer *_defer // innermost defer 347 m *m // current m; offset known to arm liblink 348 // Not for gccgo: sched gobuf 349 syscallsp uintptr // if status==Gsyscall, syscallsp = sched.sp to use during gc 350 syscallpc uintptr // if status==Gsyscall, syscallpc = sched.pc to use during gc 351 // Not for gccgo: stktopsp uintptr // expected sp at top of stack, to check in traceback 352 param unsafe.Pointer // passed parameter on wakeup 353 atomicstatus uint32 354 // Not for gccgo: stackLock uint32 // sigprof/scang lock; TODO: fold in to atomicstatus 355 goid int64 356 waitsince int64 // approx time when the g become blocked 357 waitreason string // if status==Gwaiting 358 schedlink guintptr 359 preempt bool // preemption signal, duplicates stackguard0 = stackpreempt 360 paniconfault bool // panic (instead of crash) on unexpected fault address 361 preemptscan bool // preempted g does scan for gc 362 gcscandone bool // g has scanned stack; protected by _Gscan bit in status 363 gcscanvalid bool // false at start of gc cycle, true if G has not run since last scan; TODO: remove? 364 throwsplit bool // must not split stack 365 raceignore int8 // ignore race detection events 366 sysblocktraced bool // StartTrace has emitted EvGoInSyscall about this goroutine 367 sysexitticks int64 // cputicks when syscall has returned (for tracing) 368 traceseq uint64 // trace event sequencer 369 tracelastp puintptr // last P emitted an event for this goroutine 370 lockedm muintptr 371 sig uint32 372 writebuf []byte 373 sigcode0 uintptr 374 sigcode1 uintptr 375 sigpc uintptr 376 gopc uintptr // pc of go statement that created this goroutine 377 startpc uintptr // pc of goroutine function 378 // Not for gccgo: racectx uintptr 379 waiting *sudog // sudog structures this g is waiting on (that have a valid elem ptr); in lock order 380 // Not for gccgo: cgoCtxt []uintptr // cgo traceback context 381 labels unsafe.Pointer // profiler labels 382 timer *timer // cached timer for time.Sleep 383 selectDone uint32 // are we participating in a select and did someone win the race? 384 385 // Per-G GC state 386 387 // gcAssistBytes is this G's GC assist credit in terms of 388 // bytes allocated. If this is positive, then the G has credit 389 // to allocate gcAssistBytes bytes without assisting. If this 390 // is negative, then the G must correct this by performing 391 // scan work. We track this in bytes to make it fast to update 392 // and check for debt in the malloc hot path. The assist ratio 393 // determines how this corresponds to scan work debt. 394 gcAssistBytes int64 395 396 // Remaining fields are specific to gccgo. 397 398 exception unsafe.Pointer // current exception being thrown 399 isforeign bool // whether current exception is not from Go 400 401 // When using split-stacks, these fields holds the results of 402 // __splitstack_find while executing a syscall. These are used 403 // by the garbage collector to scan the goroutine's stack. 404 // 405 // When not using split-stacks, g0 stacks are allocated by the 406 // libc and other goroutine stacks are allocated by malg. 407 // gcstack: unused (sometimes cleared) 408 // gcstacksize: g0: 0; others: size of stack 409 // gcnextsegment: unused 410 // gcnextsp: current SP while executing a syscall 411 // gcinitialsp: g0: top of stack; others: start of stack memory 412 // gcnextsp2: current secondary stack pointer (if present) 413 // gcinitialsp2: start of secondary stack (if present) 414 gcstack uintptr 415 gcstacksize uintptr 416 gcnextsegment uintptr 417 gcnextsp uintptr 418 gcinitialsp unsafe.Pointer 419 gcnextsp2 uintptr 420 gcinitialsp2 unsafe.Pointer 421 422 // gcregs holds the register values while executing a syscall. 423 // This is set by getcontext and scanned by the garbage collector. 424 gcregs g_ucontext_t 425 426 entry func(unsafe.Pointer) // goroutine function to run 427 entryfn uintptr // function address passed to __go_go 428 fromgogo bool // whether entered from gogo function 429 430 scanningself bool // whether goroutine is scanning its own stack 431 432 isSystemGoroutine bool // whether goroutine is a "system" goroutine 433 434 traceback *tracebackg // stack traceback buffer 435 436 context g_ucontext_t // saved context for setcontext 437 stackcontext [10]uintptr // split-stack context 438} 439 440type m struct { 441 g0 *g // goroutine with scheduling stack 442 // Not for gccgo: morebuf gobuf // gobuf arg to morestack 443 // Not for gccgo: divmod uint32 // div/mod denominator for arm - known to liblink 444 445 // Fields not known to debuggers. 446 procid uint64 // for debuggers, but offset not hard-coded 447 gsignal *g // signal-handling g 448 // Not for gccgo: goSigStack gsignalStack // Go-allocated signal handling stack 449 sigmask sigset // storage for saved signal mask 450 // Not for gccgo: tls [6]uintptr // thread-local storage (for x86 extern register) 451 mstartfn func() 452 curg *g // current running goroutine 453 caughtsig guintptr // goroutine running during fatal signal 454 p puintptr // attached p for executing go code (nil if not executing go code) 455 nextp puintptr 456 id int64 457 mallocing int32 458 throwing int32 459 preemptoff string // if != "", keep curg running on this m 460 locks int32 461 softfloat int32 462 dying int32 463 profilehz int32 464 helpgc int32 465 spinning bool // m is out of work and is actively looking for work 466 blocked bool // m is blocked on a note 467 inwb bool // m is executing a write barrier 468 newSigstack bool // minit on C thread called sigaltstack 469 printlock int8 470 incgo bool // m is executing a cgo call 471 freeWait uint32 // if == 0, safe to free g0 and delete m (atomic) 472 fastrand [2]uint32 473 needextram bool 474 traceback uint8 475 ncgocall uint64 // number of cgo calls in total 476 ncgo int32 // number of cgo calls currently in progress 477 // Not for gccgo: cgoCallersUse uint32 // if non-zero, cgoCallers in use temporarily 478 // Not for gccgo: cgoCallers *cgoCallers // cgo traceback if crashing in cgo call 479 park note 480 alllink *m // on allm 481 schedlink muintptr 482 mcache *mcache 483 lockedg guintptr 484 createstack [32]location // stack that created this thread. 485 // Not for gccgo: freglo [16]uint32 // d[i] lsb and f[i] 486 // Not for gccgo: freghi [16]uint32 // d[i] msb and f[i+16] 487 // Not for gccgo: fflag uint32 // floating point compare flags 488 lockedExt uint32 // tracking for external LockOSThread 489 lockedInt uint32 // tracking for internal lockOSThread 490 nextwaitm muintptr // next m waiting for lock 491 waitunlockf unsafe.Pointer // todo go func(*g, unsafe.pointer) bool 492 waitlock unsafe.Pointer 493 waittraceev byte 494 waittraceskip int 495 startingtrace bool 496 syscalltick uint32 497 // Not for gccgo: thread uintptr // thread handle 498 freelink *m // on sched.freem 499 500 // these are here because they are too large to be on the stack 501 // of low-level NOSPLIT functions. 502 // Not for gccgo: libcall libcall 503 // Not for gccgo: libcallpc uintptr // for cpu profiler 504 // Not for gccgo: libcallsp uintptr 505 // Not for gccgo: libcallg guintptr 506 // Not for gccgo: syscall libcall // stores syscall parameters on windows 507 508 mos mOS 509 510 // Remaining fields are specific to gccgo. 511 512 gsignalstack unsafe.Pointer // stack for gsignal 513 gsignalstacksize uintptr 514 515 dropextram bool // drop after call is done 516 exiting bool // thread is exiting 517 518 gcing int32 519} 520 521type p struct { 522 lock mutex 523 524 id int32 525 status uint32 // one of pidle/prunning/... 526 link puintptr 527 schedtick uint32 // incremented on every scheduler call 528 syscalltick uint32 // incremented on every system call 529 sysmontick sysmontick // last tick observed by sysmon 530 m muintptr // back-link to associated m (nil if idle) 531 mcache *mcache 532 racectx uintptr 533 534 // gccgo has only one size of defer. 535 deferpool []*_defer 536 deferpoolbuf [32]*_defer 537 538 // Cache of goroutine ids, amortizes accesses to runtime·sched.goidgen. 539 goidcache uint64 540 goidcacheend uint64 541 542 // Queue of runnable goroutines. Accessed without lock. 543 runqhead uint32 544 runqtail uint32 545 runq [256]guintptr 546 // runnext, if non-nil, is a runnable G that was ready'd by 547 // the current G and should be run next instead of what's in 548 // runq if there's time remaining in the running G's time 549 // slice. It will inherit the time left in the current time 550 // slice. If a set of goroutines is locked in a 551 // communicate-and-wait pattern, this schedules that set as a 552 // unit and eliminates the (potentially large) scheduling 553 // latency that otherwise arises from adding the ready'd 554 // goroutines to the end of the run queue. 555 runnext guintptr 556 557 // Available G's (status == Gdead) 558 gfree *g 559 gfreecnt int32 560 561 sudogcache []*sudog 562 sudogbuf [128]*sudog 563 564 tracebuf traceBufPtr 565 566 // traceSweep indicates the sweep events should be traced. 567 // This is used to defer the sweep start event until a span 568 // has actually been swept. 569 traceSweep bool 570 // traceSwept and traceReclaimed track the number of bytes 571 // swept and reclaimed by sweeping in the current sweep loop. 572 traceSwept, traceReclaimed uintptr 573 574 palloc persistentAlloc // per-P to avoid mutex 575 576 // Per-P GC state 577 gcAssistTime int64 // Nanoseconds in assistAlloc 578 gcFractionalMarkTime int64 // Nanoseconds in fractional mark worker 579 gcBgMarkWorker guintptr 580 gcMarkWorkerMode gcMarkWorkerMode 581 582 // gcMarkWorkerStartTime is the nanotime() at which this mark 583 // worker started. 584 gcMarkWorkerStartTime int64 585 586 // gcw is this P's GC work buffer cache. The work buffer is 587 // filled by write barriers, drained by mutator assists, and 588 // disposed on certain GC state transitions. 589 gcw gcWork 590 591 // wbBuf is this P's GC write barrier buffer. 592 // 593 // TODO: Consider caching this in the running G. 594 wbBuf wbBuf 595 596 runSafePointFn uint32 // if 1, run sched.safePointFn at next safe point 597 598 pad [sys.CacheLineSize]byte 599} 600 601type schedt struct { 602 // accessed atomically. keep at top to ensure alignment on 32-bit systems. 603 goidgen uint64 604 lastpoll uint64 605 606 lock mutex 607 608 // When increasing nmidle, nmidlelocked, nmsys, or nmfreed, be 609 // sure to call checkdead(). 610 611 midle muintptr // idle m's waiting for work 612 nmidle int32 // number of idle m's waiting for work 613 nmidlelocked int32 // number of locked m's waiting for work 614 mnext int64 // number of m's that have been created and next M ID 615 maxmcount int32 // maximum number of m's allowed (or die) 616 nmsys int32 // number of system m's not counted for deadlock 617 nmfreed int64 // cumulative number of freed m's 618 619 ngsys uint32 // number of system goroutines; updated atomically 620 621 pidle puintptr // idle p's 622 npidle uint32 623 nmspinning uint32 // See "Worker thread parking/unparking" comment in proc.go. 624 625 // Global runnable queue. 626 runqhead guintptr 627 runqtail guintptr 628 runqsize int32 629 630 // Global cache of dead G's. 631 gflock mutex 632 gfree *g 633 ngfree int32 634 635 // Central cache of sudog structs. 636 sudoglock mutex 637 sudogcache *sudog 638 639 // Central pool of available defer structs. 640 deferlock mutex 641 deferpool *_defer 642 643 // freem is the list of m's waiting to be freed when their 644 // m.exited is set. Linked through m.freelink. 645 freem *m 646 647 gcwaiting uint32 // gc is waiting to run 648 stopwait int32 649 stopnote note 650 sysmonwait uint32 651 sysmonnote note 652 653 // safepointFn should be called on each P at the next GC 654 // safepoint if p.runSafePointFn is set. 655 safePointFn func(*p) 656 safePointWait int32 657 safePointNote note 658 659 profilehz int32 // cpu profiling rate 660 661 procresizetime int64 // nanotime() of last change to gomaxprocs 662 totaltime int64 // ∫gomaxprocs dt up to procresizetime 663} 664 665// Values for the flags field of a sigTabT. 666const ( 667 _SigNotify = 1 << iota // let signal.Notify have signal, even if from kernel 668 _SigKill // if signal.Notify doesn't take it, exit quietly 669 _SigThrow // if signal.Notify doesn't take it, exit loudly 670 _SigPanic // if the signal is from the kernel, panic 671 _SigDefault // if the signal isn't explicitly requested, don't monitor it 672 _SigGoExit // cause all runtime procs to exit (only used on Plan 9). 673 _SigSetStack // add SA_ONSTACK to libc handler 674 _SigUnblock // always unblock; see blockableSig 675 _SigIgn // _SIG_DFL action is to ignore the signal 676) 677 678// Lock-free stack node. 679// // Also known to export_test.go. 680type lfnode struct { 681 next uint64 682 pushcnt uintptr 683} 684 685type forcegcstate struct { 686 lock mutex 687 g *g 688 idle uint32 689} 690 691// startup_random_data holds random bytes initialized at startup. These come from 692// the ELF AT_RANDOM auxiliary vector (vdso_linux_amd64.go or os_linux_386.go). 693var startupRandomData []byte 694 695// extendRandom extends the random numbers in r[:n] to the whole slice r. 696// Treats n<0 as n==0. 697func extendRandom(r []byte, n int) { 698 if n < 0 { 699 n = 0 700 } 701 for n < len(r) { 702 // Extend random bits using hash function & time seed 703 w := n 704 if w > 16 { 705 w = 16 706 } 707 h := memhash(unsafe.Pointer(&r[n-w]), uintptr(nanotime()), uintptr(w)) 708 for i := 0; i < sys.PtrSize && n < len(r); i++ { 709 r[n] = byte(h) 710 n++ 711 h >>= 8 712 } 713 } 714} 715 716// A _defer holds an entry on the list of deferred calls. 717// If you add a field here, add code to clear it in freedefer. 718type _defer struct { 719 // The next entry in the stack. 720 link *_defer 721 722 // The stack variable for the function which called this defer 723 // statement. This is set to true if we are returning from 724 // that function, false if we are panicing through it. 725 frame *bool 726 727 // The value of the panic stack when this function is 728 // deferred. This function can not recover this value from 729 // the panic stack. This can happen if a deferred function 730 // has a defer statement itself. 731 panicStack *_panic 732 733 // The panic that caused the defer to run. This is used to 734 // discard panics that have already been handled. 735 _panic *_panic 736 737 // The function to call. 738 pfn uintptr 739 740 // The argument to pass to the function. 741 arg unsafe.Pointer 742 743 // The return address that a recover thunk matches against. 744 // This is set by __go_set_defer_retaddr which is called by 745 // the thunks created by defer statements. 746 retaddr uintptr 747 748 // Set to true if a function created by reflect.MakeFunc is 749 // permitted to recover. The return address of such a 750 // function function will be somewhere in libffi, so __retaddr 751 // is not useful. 752 makefunccanrecover bool 753} 754 755// panics 756// This is the gccgo version. 757type _panic struct { 758 // The next entry in the stack. 759 link *_panic 760 761 // The value associated with this panic. 762 arg interface{} 763 764 // Whether this panic has been recovered. 765 recovered bool 766 767 // Whether this panic was pushed on the stack because of an 768 // exception thrown in some other language. 769 isforeign bool 770 771 // Whether this panic was already seen by a deferred function 772 // which called panic again. 773 aborted bool 774} 775 776const ( 777 _TraceRuntimeFrames = 1 << iota // include frames for internal runtime functions. 778 _TraceTrap // the initial PC, SP are from a trap, not a return PC from a call 779 _TraceJumpStack // if traceback is on a systemstack, resume trace at g that called into it 780) 781 782// The maximum number of frames we print for a traceback 783const _TracebackMaxFrames = 100 784 785var ( 786 allglen uintptr 787 allm *m 788 allp []*p // len(allp) == gomaxprocs; may change at safe points, otherwise immutable 789 allpLock mutex // Protects P-less reads of allp and all writes 790 gomaxprocs int32 791 ncpu int32 792 forcegc forcegcstate 793 sched schedt 794 newprocs int32 795 796 // Information about what cpu features are available. 797 // Set on startup in asm_{x86,amd64}.s. 798 // Packages outside the runtime should not use these 799 // as they are not an external api. 800 cpuid_ecx uint32 801 support_aes bool 802 803 // cpuid_edx uint32 804 // cpuid_ebx7 uint32 805 // lfenceBeforeRdtsc bool 806 // support_avx bool 807 // support_avx2 bool 808 // support_bmi1 bool 809 // support_bmi2 bool 810 811// goarm uint8 // set by cmd/link on arm systems 812// framepointer_enabled bool // set by cmd/link 813) 814 815// Set by the linker so the runtime can determine the buildmode. 816var ( 817 islibrary bool // -buildmode=c-shared 818 isarchive bool // -buildmode=c-archive 819) 820 821// Types that are only used by gccgo. 822 823// g_ucontext_t is a Go version of the C ucontext_t type, used by getcontext. 824// _sizeof_ucontext_t is defined by mkrsysinfo.sh from <ucontext.h>. 825// On some systems getcontext and friends require a value that is 826// aligned to a 16-byte boundary. We implement this by increasing the 827// required size and picking an appropriate offset when we use the 828// array. 829type g_ucontext_t [(_sizeof_ucontext_t + 15) / unsafe.Sizeof(uintptr(0))]uintptr 830 831// sigset is the Go version of the C type sigset_t. 832// _sigset_t is defined by the Makefile from <signal.h>. 833type sigset _sigset_t 834 835// getMemstats returns a pointer to the internal memstats variable, 836// for C code. 837//go:linkname getMemstats runtime.getMemstats 838func getMemstats() *mstats { 839 return &memstats 840} 841