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| author | Ondřej Surý <ondrej@sury.org> | 2011-09-13 13:11:55 +0200 | 
|---|---|---|
| committer | Ondřej Surý <ondrej@sury.org> | 2011-09-13 13:11:55 +0200 | 
| commit | 80f18fc933cf3f3e829c5455a1023d69f7b86e52 (patch) | |
| tree | 4b825dc642cb6eb9a060e54bf8d69288fbee4904 /src/pkg/runtime/linux/thread.c | |
| parent | 28592ee1ea1f5cdffcf85472f9de0285d928cf12 (diff) | |
| download | golang-80f18fc933cf3f3e829c5455a1023d69f7b86e52.tar.gz | |
Imported Upstream version 60
Diffstat (limited to 'src/pkg/runtime/linux/thread.c')
| -rw-r--r-- | src/pkg/runtime/linux/thread.c | 305 | 
1 files changed, 0 insertions, 305 deletions
| diff --git a/src/pkg/runtime/linux/thread.c b/src/pkg/runtime/linux/thread.c deleted file mode 100644 index 7c7ca7b4e..000000000 --- a/src/pkg/runtime/linux/thread.c +++ /dev/null @@ -1,305 +0,0 @@ -// Copyright 2009 The Go Authors. All rights reserved. -// Use of this source code is governed by a BSD-style -// license that can be found in the LICENSE file. - -#include "runtime.h" -#include "defs.h" -#include "os.h" -#include "stack.h" - -extern SigTab runtime·sigtab[]; - -// Linux futex. -// -//	futexsleep(uint32 *addr, uint32 val) -//	futexwakeup(uint32 *addr) -// -// Futexsleep atomically checks if *addr == val and if so, sleeps on addr. -// Futexwakeup wakes up one thread sleeping on addr. -// Futexsleep is allowed to wake up spuriously. - -enum -{ -	FUTEX_WAIT = 0, -	FUTEX_WAKE = 1, - -	EINTR = 4, -	EAGAIN = 11, -}; - -// TODO(rsc): I tried using 1<<40 here but futex woke up (-ETIMEDOUT). -// I wonder if the timespec that gets to the kernel -// actually has two 32-bit numbers in it, so that -// a 64-bit 1<<40 ends up being 0 seconds, -// 1<<8 nanoseconds. -static Timespec longtime = -{ -	1<<30,	// 34 years -	0 -}; - -// Atomically, -//	if(*addr == val) sleep -// Might be woken up spuriously; that's allowed. -static void -futexsleep(uint32 *addr, uint32 val) -{ -	// Some Linux kernels have a bug where futex of -	// FUTEX_WAIT returns an internal error code -	// as an errno.  Libpthread ignores the return value -	// here, and so can we: as it says a few lines up, -	// spurious wakeups are allowed. -	runtime·futex(addr, FUTEX_WAIT, val, &longtime, nil, 0); -} - -// If any procs are sleeping on addr, wake up at least one. -static void -futexwakeup(uint32 *addr) -{ -	int64 ret; - -	ret = runtime·futex(addr, FUTEX_WAKE, 1, nil, nil, 0); - -	if(ret >= 0) -		return; - -	// I don't know that futex wakeup can return -	// EAGAIN or EINTR, but if it does, it would be -	// safe to loop and call futex again. - -	runtime·prints("futexwakeup addr="); -	runtime·printpointer(addr); -	runtime·prints(" returned "); -	runtime·printint(ret); -	runtime·prints("\n"); -	*(int32*)0x1006 = 0x1006; -} - - -// Lock and unlock. -// -// The lock state is a single 32-bit word that holds -// a 31-bit count of threads waiting for the lock -// and a single bit (the low bit) saying whether the lock is held. -// The uncontended case runs entirely in user space. -// When contention is detected, we defer to the kernel (futex). -// -// A reminder: compare-and-swap runtime·cas(addr, old, new) does -//	if(*addr == old) { *addr = new; return 1; } -//	else return 0; -// but atomically. - -static void -futexlock(Lock *l) -{ -	uint32 v; - -again: -	v = l->key; -	if((v&1) == 0){ -		if(runtime·cas(&l->key, v, v|1)){ -			// Lock wasn't held; we grabbed it. -			return; -		} -		goto again; -	} - -	// Lock was held; try to add ourselves to the waiter count. -	if(!runtime·cas(&l->key, v, v+2)) -		goto again; - -	// We're accounted for, now sleep in the kernel. -	// -	// We avoid the obvious lock/unlock race because -	// the kernel won't put us to sleep if l->key has -	// changed underfoot and is no longer v+2. -	// -	// We only really care that (v&1) == 1 (the lock is held), -	// and in fact there is a futex variant that could -	// accommodate that check, but let's not get carried away.) -	futexsleep(&l->key, v+2); - -	// We're awake: remove ourselves from the count. -	for(;;){ -		v = l->key; -		if(v < 2) -			runtime·throw("bad lock key"); -		if(runtime·cas(&l->key, v, v-2)) -			break; -	} - -	// Try for the lock again. -	goto again; -} - -static void -futexunlock(Lock *l) -{ -	uint32 v; - -	// Atomically get value and clear lock bit. -again: -	v = l->key; -	if((v&1) == 0) -		runtime·throw("unlock of unlocked lock"); -	if(!runtime·cas(&l->key, v, v&~1)) -		goto again; - -	// If there were waiters, wake one. -	if(v & ~1) -		futexwakeup(&l->key); -} - -void -runtime·lock(Lock *l) -{ -	if(m->locks < 0) -		runtime·throw("lock count"); -	m->locks++; -	futexlock(l); -} - -void -runtime·unlock(Lock *l) -{ -	m->locks--; -	if(m->locks < 0) -		runtime·throw("lock count"); -	futexunlock(l); -} - -void -runtime·destroylock(Lock*) -{ -} - - -// One-time notifications. -// -// Since the lock/unlock implementation already -// takes care of sleeping in the kernel, we just reuse it. -// (But it's a weird use, so it gets its own interface.) -// -// We use a lock to represent the event: -// unlocked == event has happened. -// Thus the lock starts out locked, and to wait for the -// event you try to lock the lock.  To signal the event, -// you unlock the lock. - -void -runtime·noteclear(Note *n) -{ -	n->lock.key = 0;	// memset(n, 0, sizeof *n) -	futexlock(&n->lock); -} - -void -runtime·notewakeup(Note *n) -{ -	futexunlock(&n->lock); -} - -void -runtime·notesleep(Note *n) -{ -	futexlock(&n->lock); -	futexunlock(&n->lock);	// Let other sleepers find out too. -} - - -// Clone, the Linux rfork. -enum -{ -	CLONE_VM = 0x100, -	CLONE_FS = 0x200, -	CLONE_FILES = 0x400, -	CLONE_SIGHAND = 0x800, -	CLONE_PTRACE = 0x2000, -	CLONE_VFORK = 0x4000, -	CLONE_PARENT = 0x8000, -	CLONE_THREAD = 0x10000, -	CLONE_NEWNS = 0x20000, -	CLONE_SYSVSEM = 0x40000, -	CLONE_SETTLS = 0x80000, -	CLONE_PARENT_SETTID = 0x100000, -	CLONE_CHILD_CLEARTID = 0x200000, -	CLONE_UNTRACED = 0x800000, -	CLONE_CHILD_SETTID = 0x1000000, -	CLONE_STOPPED = 0x2000000, -	CLONE_NEWUTS = 0x4000000, -	CLONE_NEWIPC = 0x8000000, -}; - -void -runtime·newosproc(M *m, G *g, void *stk, void (*fn)(void)) -{ -	int32 ret; -	int32 flags; - -	/* -	 * note: strace gets confused if we use CLONE_PTRACE here. -	 */ -	flags = CLONE_VM	/* share memory */ -		| CLONE_FS	/* share cwd, etc */ -		| CLONE_FILES	/* share fd table */ -		| CLONE_SIGHAND	/* share sig handler table */ -		| CLONE_THREAD	/* revisit - okay for now */ -		; - -	m->tls[0] = m->id;	// so 386 asm can find it -	if(0){ -		runtime·printf("newosproc stk=%p m=%p g=%p fn=%p clone=%p id=%d/%d ostk=%p\n", -			stk, m, g, fn, runtime·clone, m->id, m->tls[0], &m); -	} - -	if((ret = runtime·clone(flags, stk, m, g, fn)) < 0) { -		runtime·printf("runtime: failed to create new OS thread (have %d already; errno=%d)\n", runtime·mcount(), -ret); -		runtime·throw("runtime.newosproc"); -	} -} - -void -runtime·osinit(void) -{ -} - -void -runtime·goenvs(void) -{ -	runtime·goenvs_unix(); -} - -// Called to initialize a new m (including the bootstrap m). -void -runtime·minit(void) -{ -	// Initialize signal handling. -	m->gsignal = runtime·malg(32*1024);	// OS X wants >=8K, Linux >=2K -	runtime·signalstack(m->gsignal->stackguard - StackGuard, 32*1024); -} - -void -runtime·sigpanic(void) -{ -	switch(g->sig) { -	case SIGBUS: -		if(g->sigcode0 == BUS_ADRERR && g->sigcode1 < 0x1000) -			runtime·panicstring("invalid memory address or nil pointer dereference"); -		runtime·printf("unexpected fault address %p\n", g->sigcode1); -		runtime·throw("fault"); -	case SIGSEGV: -		if((g->sigcode0 == 0 || g->sigcode0 == SEGV_MAPERR || g->sigcode0 == SEGV_ACCERR) && g->sigcode1 < 0x1000) -			runtime·panicstring("invalid memory address or nil pointer dereference"); -		runtime·printf("unexpected fault address %p\n", g->sigcode1); -		runtime·throw("fault"); -	case SIGFPE: -		switch(g->sigcode0) { -		case FPE_INTDIV: -			runtime·panicstring("integer divide by zero"); -		case FPE_INTOVF: -			runtime·panicstring("integer overflow"); -		} -		runtime·panicstring("floating point error"); -	} -	runtime·panicstring(runtime·sigtab[g->sig].name); -} | 
