Context Navigation

kernel.cfa @ f2384c9a

ADTarm-ehast-experimentalenumforall-pointer-decayjacob/cs343-translationnew-astnew-ast-unique-exprpthread-emulationqualifiedEnum

Last change on this file since f2384c9a was f2384c9a, checked in by Thierry Delisle <tdelisle@…>, 4 years ago
Added forward/reverse rng for later use in the ready queue
Property mode set to `100644`
File size: 22.2 KB

Line
1	//
2	// Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo
3	//
4	// The contents of this file are covered under the licence agreement in the
5	// file "LICENCE" distributed with Cforall.
6	//
7	// kernel.c --
8	//
9	// Author : Thierry Delisle
10	// Created On : Tue Jan 17 12:27:26 2017
11	// Last Modified By : Peter A. Buhr
12	// Last Modified On : Thu Jul 9 06:22:54 2020
13	// Update Count : 66
14	//
15
16	#define __cforall_thread__
17	// #define __CFA_DEBUG_PRINT_RUNTIME_CORE__
18
19	//C Includes
20	#include <errno.h>
21	#include <stdio.h>
22	#include <signal.h>
23	#include <unistd.h>
24
25	//CFA Includes
26	#include "kernel_private.hfa"
27	#include "preemption.hfa"
28
29	//Private includes
30	#define __CFA_INVOKE_PRIVATE__
31	#include "invoke.h"
32
33
34	//-----------------------------------------------------------------------------
35	// Some assembly required
36	#if defined( __i386 )
37	// mxcr : SSE Status and Control bits (control bits are preserved across function calls)
38	// fcw : X87 FPU control word (preserved across function calls)
39	#define __x87_store \
40	uint32_t __mxcr; \
41	uint16_t __fcw; \
42	__asm__ volatile ( \
43	"stmxcsr %0\n" \
44	"fnstcw %1\n" \
45	: "=m" (__mxcr),\
46	"=m" (__fcw) \
47	)
48
49	#define __x87_load \
50	__asm__ volatile ( \
51	"fldcw %1\n" \
52	"ldmxcsr %0\n" \
53	::"m" (__mxcr),\
54	"m" (__fcw) \
55	)
56
57	#elif defined( __x86_64 )
58	#define __x87_store \
59	uint32_t __mxcr; \
60	uint16_t __fcw; \
61	__asm__ volatile ( \
62	"stmxcsr %0\n" \
63	"fnstcw %1\n" \
64	: "=m" (__mxcr),\
65	"=m" (__fcw) \
66	)
67
68	#define __x87_load \
69	__asm__ volatile ( \
70	"fldcw %1\n" \
71	"ldmxcsr %0\n" \
72	:: "m" (__mxcr),\
73	"m" (__fcw) \
74	)
75
76
77	#elif defined( __ARM_ARCH )
78	#else
79	#error unknown hardware architecture
80	#endif
81
82	extern $thread * mainThread;
83	extern processor * mainProcessor;
84
85	//-----------------------------------------------------------------------------
86	// Kernel Scheduling logic
87	static $thread * __next_thread(cluster * this);
88	static $thread * __next_thread_slow(cluster * this);
89	static void __run_thread(processor * this, $thread * dst);
90	static void __wake_one(struct __processor_id_t * id, cluster * cltr);
91
92	static void push (__cluster_idles & idles, processor & proc);
93	static void remove(__cluster_idles & idles, processor & proc);
94	static [unsigned idle, unsigned total, * processor] query( & __cluster_idles idles );
95
96
97	//=============================================================================================
98	// Kernel Scheduling logic
99	//=============================================================================================
100	//Main of the processor contexts
101	void main(processorCtx_t & runner) {
102	// Because of a bug, we couldn't initialized the seed on construction
103	// Do it here
104	kernelTLS.rand_seed ^= rdtscl();
105	kernelTLS.ready_rng.fwd_seed = 25214903917_l64u * (rdtscl() ^ (uintptr_t)&runner);
106	__tls_rand_advance_bck();
107
108	processor * this = runner.proc;
109	verify(this);
110
111	__cfadbg_print_safe(runtime_core, "Kernel : core %p starting\n", this);
112	#if !defined(__CFA_NO_STATISTICS__)
113	if( this->print_halts ) {
114	__cfaabi_bits_print_safe( STDOUT_FILENO, "Processor : %d - %s (%p)\n", this->id, this->name, (void*)this);
115	}
116	#endif
117
118	{
119	// Setup preemption data
120	preemption_scope scope = { this };
121
122	__cfadbg_print_safe(runtime_core, "Kernel : core %p started\n", this);
123
124	$thread * readyThread = 0p;
125	MAIN_LOOP:
126	for() {
127	// Try to get the next thread
128	readyThread = __next_thread( this->cltr );
129
130	if( !readyThread ) {
131	readyThread = __next_thread_slow( this->cltr );
132	}
133
134	HALT:
135	if( !readyThread ) {
136	// Don't block if we are done
137	if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
138
139	#if !defined(__CFA_NO_STATISTICS__)
140	__tls_stats()->ready.sleep.halts++;
141	#endif
142
143	// Push self to idle stack
144	push(this->cltr->idles, * this);
145
146	// Confirm the ready-queue is empty
147	readyThread = __next_thread_slow( this->cltr );
148	if( readyThread ) {
149	// A thread was found, cancel the halt
150	remove(this->cltr->idles, * this);
151
152	#if !defined(__CFA_NO_STATISTICS__)
153	__tls_stats()->ready.sleep.cancels++;
154	#endif
155
156	// continue the mai loop
157	break HALT;
158	}
159
160	#if !defined(__CFA_NO_STATISTICS__)
161	if(this->print_halts) {
162	__cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 0\n", this->id, rdtscl());
163	}
164	#endif
165
166	wait( this->idle );
167
168	#if !defined(__CFA_NO_STATISTICS__)
169	if(this->print_halts) {
170	__cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 1\n", this->id, rdtscl());
171	}
172	#endif
173
174	// We were woken up, remove self from idle
175	remove(this->cltr->idles, * this);
176
177	// DON'T just proceed, start looking again
178	continue MAIN_LOOP;
179	}
180
181	/* paranoid */ verify( readyThread );
182
183	// We found a thread run it
184	__run_thread(this, readyThread);
185
186	// Are we done?
187	if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
188	}
189
190	__cfadbg_print_safe(runtime_core, "Kernel : core %p stopping\n", this);
191	}
192
193	V( this->terminated );
194
195	if(this == mainProcessor) {
196	// HACK : the coroutine context switch expects this_thread to be set
197	// and it make sense for it to be set in all other cases except here
198	// fake it
199	kernelTLS.this_thread = mainThread;
200	}
201
202	__cfadbg_print_safe(runtime_core, "Kernel : core %p terminated\n", this);
203	}
204
205	static int * __volatile_errno() __attribute__((noinline));
206	static int * __volatile_errno() { asm(""); return &errno; }
207
208	// KERNEL ONLY
209	// runThread runs a thread by context switching
210	// from the processor coroutine to the target thread
211	static void __run_thread(processor * this, $thread * thrd_dst) {
212	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
213	/* paranoid */ verifyf( thrd_dst->state == Ready \|\| thrd_dst->preempted != __NO_PREEMPTION, "state : %d, preempted %d\n", thrd_dst->state, thrd_dst->preempted);
214	/* paranoid */ verifyf( thrd_dst->link.next == 0p, "Expected null got %p", thrd_dst->link.next );
215	__builtin_prefetch( thrd_dst->context.SP );
216
217	$coroutine * proc_cor = get_coroutine(this->runner);
218
219	// Update global state
220	kernelTLS.this_thread = thrd_dst;
221
222	// set state of processor coroutine to inactive
223	verify(proc_cor->state == Active);
224	proc_cor->state = Blocked;
225
226	// Actually run the thread
227	RUNNING: while(true) {
228	thrd_dst->preempted = __NO_PREEMPTION;
229	thrd_dst->state = Active;
230
231	__cfaabi_dbg_debug_do(
232	thrd_dst->park_stale = true;
233	thrd_dst->unpark_stale = true;
234	)
235
236	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
237	/* paranoid */ verify( kernelTLS.this_thread == thrd_dst );
238	/* paranoid */ verifyf( ((uintptr_t)thrd_dst->context.SP) < ((uintptr_t)__get_stack(thrd_dst->curr_cor)->base ) \|\| thrd_dst->curr_cor == proc_cor, "ERROR : Destination $thread %p has been corrupted.\n StackPointer too small.\n", thrd_dst ); // add escape condition if we are setting up the processor
239	/* paranoid */ verifyf( ((uintptr_t)thrd_dst->context.SP) > ((uintptr_t)__get_stack(thrd_dst->curr_cor)->limit) \|\| thrd_dst->curr_cor == proc_cor, "ERROR : Destination $thread %p has been corrupted.\n StackPointer too large.\n", thrd_dst ); // add escape condition if we are setting up the processor
240
241	// set context switch to the thread that the processor is executing
242	verify( thrd_dst->context.SP );
243	__cfactx_switch( &proc_cor->context, &thrd_dst->context );
244	// when __cfactx_switch returns we are back in the processor coroutine
245
246	/* paranoid */ verifyf( ((uintptr_t)thrd_dst->context.SP) > ((uintptr_t)__get_stack(thrd_dst->curr_cor)->limit), "ERROR : Destination $thread %p has been corrupted.\n StackPointer too large.\n", thrd_dst );
247	/* paranoid */ verifyf( ((uintptr_t)thrd_dst->context.SP) < ((uintptr_t)__get_stack(thrd_dst->curr_cor)->base ), "ERROR : Destination $thread %p has been corrupted.\n StackPointer too small.\n", thrd_dst );
248	/* paranoid */ verify( kernelTLS.this_thread == thrd_dst );
249	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
250
251
252	// We just finished running a thread, there are a few things that could have happened.
253	// 1 - Regular case : the thread has blocked and now one has scheduled it yet.
254	// 2 - Racy case : the thread has blocked but someone has already tried to schedule it.
255	// 4 - Preempted
256	// In case 1, we may have won a race so we can't write to the state again.
257	// In case 2, we lost the race so we now own the thread.
258
259	if(unlikely(thrd_dst->preempted != __NO_PREEMPTION)) {
260	// The thread was preempted, reschedule it and reset the flag
261	__schedule_thread( (__processor_id_t*)this, thrd_dst );
262	break RUNNING;
263	}
264
265	if(unlikely(thrd_dst->state == Halted)) {
266	// The thread has halted, it should never be scheduled/run again
267	// We may need to wake someone up here since
268	unpark( this->destroyer __cfaabi_dbg_ctx2 );
269	this->destroyer = 0p;
270	break RUNNING;
271	}
272
273	/* paranoid */ verify( thrd_dst->state == Active );
274	thrd_dst->state = Blocked;
275
276	// set state of processor coroutine to active and the thread to inactive
277	int old_ticket = __atomic_fetch_sub(&thrd_dst->ticket, 1, __ATOMIC_SEQ_CST);
278	__cfaabi_dbg_debug_do( thrd_dst->park_result = old_ticket; )
279	switch(old_ticket) {
280	case 1:
281	// This is case 1, the regular case, nothing more is needed
282	break RUNNING;
283	case 2:
284	// This is case 2, the racy case, someone tried to run this thread before it finished blocking
285	// In this case, just run it again.
286	continue RUNNING;
287	default:
288	// This makes no sense, something is wrong abort
289	abort();
290	}
291	}
292
293	// Just before returning to the processor, set the processor coroutine to active
294	proc_cor->state = Active;
295	kernelTLS.this_thread = 0p;
296
297	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
298	}
299
300	// KERNEL_ONLY
301	void returnToKernel() {
302	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
303	$coroutine * proc_cor = get_coroutine(kernelTLS.this_processor->runner);
304	$thread * thrd_src = kernelTLS.this_thread;
305
306	#if !defined(__CFA_NO_STATISTICS__)
307	struct processor * last_proc = kernelTLS.this_processor;
308	#endif
309
310	// Run the thread on this processor
311	{
312	int local_errno = *__volatile_errno();
313	#if defined( __i386 ) \|\| defined( __x86_64 )
314	__x87_store;
315	#endif
316	verify( proc_cor->context.SP );
317	__cfactx_switch( &thrd_src->context, &proc_cor->context );
318	#if defined( __i386 ) \|\| defined( __x86_64 )
319	__x87_load;
320	#endif
321	*__volatile_errno() = local_errno;
322	}
323
324	#if !defined(__CFA_NO_STATISTICS__)
325	if(last_proc != kernelTLS.this_processor) {
326	__tls_stats()->ready.threads.migration++;
327	}
328	#endif
329
330	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
331	/* paranoid */ verifyf( ((uintptr_t)thrd_src->context.SP) < ((uintptr_t)__get_stack(thrd_src->curr_cor)->base ), "ERROR : Returning $thread %p has been corrupted.\n StackPointer too small.\n", thrd_src );
332	/* paranoid */ verifyf( ((uintptr_t)thrd_src->context.SP) > ((uintptr_t)__get_stack(thrd_src->curr_cor)->limit), "ERROR : Returning $thread %p has been corrupted.\n StackPointer too large.\n", thrd_src );
333	}
334
335	//-----------------------------------------------------------------------------
336	// Scheduler routines
337	// KERNEL ONLY
338	void __schedule_thread( struct __processor_id_t * id, $thread * thrd ) {
339	/* paranoid */ verify( thrd );
340	/* paranoid */ verify( thrd->state != Halted );
341	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
342	/* paranoid */ #if defined( __CFA_WITH_VERIFY__ )
343	/* paranoid */ if( thrd->state == Blocked \|\| thrd->state == Start ) assertf( thrd->preempted == __NO_PREEMPTION,
344	"Error inactive thread marked as preempted, state %d, preemption %d\n", thrd->state, thrd->preempted );
345	/* paranoid */ if( thrd->preempted != __NO_PREEMPTION ) assertf(thrd->state == Active,
346	"Error preempted thread marked as not currently running, state %d, preemption %d\n", thrd->state, thrd->preempted );
347	/* paranoid */ #endif
348	/* paranoid */ verifyf( thrd->link.next == 0p, "Expected null got %p", thrd->link.next );
349
350	if (thrd->preempted == __NO_PREEMPTION) thrd->state = Ready;
351
352	ready_schedule_lock ( id );
353	push( thrd->curr_cluster, thrd );
354	__wake_one(id, thrd->curr_cluster);
355	ready_schedule_unlock( id );
356
357	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
358	}
359
360	// KERNEL ONLY
361	static inline $thread * __next_thread(cluster * this) with( *this ) {
362	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
363
364	ready_schedule_lock ( (__processor_id_t*)kernelTLS.this_processor );
365	$thread * thrd = pop( this );
366	ready_schedule_unlock( (__processor_id_t*)kernelTLS.this_processor );
367
368	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
369	return thrd;
370	}
371
372	// KERNEL ONLY
373	static inline $thread * __next_thread_slow(cluster * this) with( *this ) {
374	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
375
376	ready_schedule_lock ( (__processor_id_t*)kernelTLS.this_processor );
377	$thread * thrd = pop_slow( this );
378	ready_schedule_unlock( (__processor_id_t*)kernelTLS.this_processor );
379
380	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
381	return thrd;
382	}
383
384	// KERNEL ONLY unpark with out disabling interrupts
385	void __unpark( struct __processor_id_t * id, $thread * thrd __cfaabi_dbg_ctx_param2 ) {
386	// record activity
387	__cfaabi_dbg_record_thrd( *thrd, false, caller );
388
389	int old_ticket = __atomic_fetch_add(&thrd->ticket, 1, __ATOMIC_SEQ_CST);
390	__cfaabi_dbg_debug_do( thrd->unpark_result = old_ticket; thrd->unpark_state = thrd->state; )
391	switch(old_ticket) {
392	case 1:
393	// Wake won the race, the thread will reschedule/rerun itself
394	break;
395	case 0:
396	/* paranoid */ verify( ! thrd->preempted != __NO_PREEMPTION );
397	/* paranoid */ verify( thrd->state == Blocked );
398
399	// Wake lost the race,
400	__schedule_thread( id, thrd );
401	break;
402	default:
403	// This makes no sense, something is wrong abort
404	abort();
405	}
406	}
407
408	void unpark( $thread * thrd __cfaabi_dbg_ctx_param2 ) {
409	if( !thrd ) return;
410
411	disable_interrupts();
412	__unpark( (__processor_id_t*)kernelTLS.this_processor, thrd __cfaabi_dbg_ctx_fwd2 );
413	enable_interrupts( __cfaabi_dbg_ctx );
414	}
415
416	void park( __cfaabi_dbg_ctx_param ) {
417	/* paranoid */ verify( kernelTLS.preemption_state.enabled );
418	disable_interrupts();
419	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
420	/* paranoid */ verify( kernelTLS.this_thread->preempted == __NO_PREEMPTION );
421
422	// record activity
423	__cfaabi_dbg_record_thrd( *kernelTLS.this_thread, true, caller );
424
425	returnToKernel();
426
427	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
428	enable_interrupts( __cfaabi_dbg_ctx );
429	/* paranoid */ verify( kernelTLS.preemption_state.enabled );
430
431	}
432
433	// KERNEL ONLY
434	void __leave_thread() {
435	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
436	returnToKernel();
437	abort();
438	}
439
440	// KERNEL ONLY
441	bool force_yield( __Preemption_Reason reason ) {
442	/* paranoid */ verify( kernelTLS.preemption_state.enabled );
443	disable_interrupts();
444	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
445
446	$thread * thrd = kernelTLS.this_thread;
447	/* paranoid */ verify(thrd->state == Active);
448
449	// SKULLDUGGERY: It is possible that we are preempting this thread just before
450	// it was going to park itself. If that is the case and it is already using the
451	// intrusive fields then we can't use them to preempt the thread
452	// If that is the case, abandon the preemption.
453	bool preempted = false;
454	if(thrd->link.next == 0p) {
455	preempted = true;
456	thrd->preempted = reason;
457	returnToKernel();
458	}
459
460	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
461	enable_interrupts_noPoll();
462	/* paranoid */ verify( kernelTLS.preemption_state.enabled );
463
464	return preempted;
465	}
466
467	//=============================================================================================
468	// Kernel Idle Sleep
469	//=============================================================================================
470	// Wake a thread from the front if there are any
471	static void __wake_one(struct __processor_id_t * id, cluster * this) {
472	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
473	/* paranoid */ verify( ready_schedule_islocked( id ) );
474
475	// Check if there is a sleeping processor
476	processor * p;
477	unsigned idle;
478	unsigned total;
479	[idle, total, p] = query(this->idles);
480
481	// If no one is sleeping, we are done
482	if( idle == 0 ) return;
483
484	// We found a processor, wake it up
485	post( p->idle );
486
487	#if !defined(__CFA_NO_STATISTICS__)
488	__tls_stats()->ready.sleep.wakes++;
489	#endif
490
491	/* paranoid */ verify( ready_schedule_islocked( id ) );
492	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
493
494	return;
495	}
496
497	// Unconditionnaly wake a thread
498	void __wake_proc(processor * this) {
499	__cfadbg_print_safe(runtime_core, "Kernel : waking Processor %p\n", this);
500
501	disable_interrupts();
502	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
503	bool ret = post( this->idle );
504	enable_interrupts( __cfaabi_dbg_ctx );
505	}
506
507	static void push (__cluster_idles & this, processor & proc) {
508	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
509	lock( this );
510	this.idle++;
511	/* paranoid */ verify( this.idle <= this.total );
512
513	insert_first(this.list, proc);
514	unlock( this );
515	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
516	}
517
518	static void remove(__cluster_idles & this, processor & proc) {
519	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
520	lock( this );
521	this.idle--;
522	/* paranoid */ verify( this.idle >= 0 );
523
524	remove(proc);
525	unlock( this );
526	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
527	}
528
529	static [unsigned idle, unsigned total, * processor] query( & __cluster_idles this ) {
530	for() {
531	uint64_t l = __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST);
532	if( 1 == (l % 2) ) { Pause(); continue; }
533	unsigned idle = this.idle;
534	unsigned total = this.total;
535	processor * proc = &this.list`first;
536	// Compiler fence is unnecessary, but gcc-8 and older incorrectly reorder code without it
537	asm volatile("": : :"memory");
538	if(l != __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST)) { Pause(); continue; }
539	return [idle, total, proc];
540	}
541	}
542
543	//=============================================================================================
544	// Unexpected Terminating logic
545	//=============================================================================================
546	static __spinlock_t kernel_abort_lock;
547	static bool kernel_abort_called = false;
548
549	void * kernel_abort(void) __attribute__ ((__nothrow__)) {
550	// abort cannot be recursively entered by the same or different processors because all signal handlers return when
551	// the globalAbort flag is true.
552	lock( kernel_abort_lock __cfaabi_dbg_ctx2 );
553
554	// first task to abort ?
555	if ( kernel_abort_called ) { // not first task to abort ?
556	unlock( kernel_abort_lock );
557
558	sigset_t mask;
559	sigemptyset( &mask );
560	sigaddset( &mask, SIGALRM ); // block SIGALRM signals
561	sigaddset( &mask, SIGUSR1 ); // block SIGALRM signals
562	sigsuspend( &mask ); // block the processor to prevent further damage during abort
563	_exit( EXIT_FAILURE ); // if processor unblocks before it is killed, terminate it
564	}
565	else {
566	kernel_abort_called = true;
567	unlock( kernel_abort_lock );
568	}
569
570	return kernelTLS.this_thread;
571	}
572
573	void kernel_abort_msg( void * kernel_data, char * abort_text, int abort_text_size ) {
574	$thread * thrd = ( $thread * ) kernel_data;
575
576	if(thrd) {
577	int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
578	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
579
580	if ( &thrd->self_cor != thrd->curr_cor ) {
581	len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
582	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
583	}
584	else {
585	__cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
586	}
587	}
588	else {
589	int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
590	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
591	}
592	}
593
594	int kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
595	return get_coroutine(kernelTLS.this_thread) == get_coroutine(mainThread) ? 4 : 2;
596	}
597
598	static __spinlock_t kernel_debug_lock;
599
600	extern "C" {
601	void __cfaabi_bits_acquire() {
602	lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
603	}
604
605	void __cfaabi_bits_release() {
606	unlock( kernel_debug_lock );
607	}
608	}
609
610	//=============================================================================================
611	// Kernel Utilities
612	//=============================================================================================
613	//-----------------------------------------------------------------------------
614	// Locks
615	void ?{}( semaphore & this, int count = 1 ) {
616	(this.lock){};
617	this.count = count;
618	(this.waiting){};
619	}
620	void ^?{}(semaphore & this) {}
621
622	bool P(semaphore & this) with( this ){
623	lock( lock __cfaabi_dbg_ctx2 );
624	count -= 1;
625	if ( count < 0 ) {
626	// queue current task
627	append( waiting, kernelTLS.this_thread );
628
629	// atomically release spin lock and block
630	unlock( lock );
631	park( __cfaabi_dbg_ctx );
632	return true;
633	}
634	else {
635	unlock( lock );
636	return false;
637	}
638	}
639
640	bool V(semaphore & this) with( this ) {
641	$thread * thrd = 0p;
642	lock( lock __cfaabi_dbg_ctx2 );
643	count += 1;
644	if ( count <= 0 ) {
645	// remove task at head of waiting list
646	thrd = pop_head( waiting );
647	}
648
649	unlock( lock );
650
651	// make new owner
652	unpark( thrd __cfaabi_dbg_ctx2 );
653
654	return thrd != 0p;
655	}
656
657	bool V(semaphore & this, unsigned diff) with( this ) {
658	$thread * thrd = 0p;
659	lock( lock __cfaabi_dbg_ctx2 );
660	int release = max(-count, (int)diff);
661	count += diff;
662	for(release) {
663	unpark( pop_head( waiting ) __cfaabi_dbg_ctx2 );
664	}
665
666	unlock( lock );
667
668	return thrd != 0p;
669	}
670
671	//-----------------------------------------------------------------------------
672	// Debug
673	__cfaabi_dbg_debug_do(
674	extern "C" {
675	void __cfaabi_dbg_record_lock(__spinlock_t & this, const char prev_name[]) {
676	this.prev_name = prev_name;
677	this.prev_thrd = kernelTLS.this_thread;
678	}
679
680	void __cfaabi_dbg_record_thrd($thread & this, bool park, const char prev_name[]) {
681	if(park) {
682	this.park_caller = prev_name;
683	this.park_stale = false;
684	}
685	else {
686	this.unpark_caller = prev_name;
687	this.unpark_stale = false;
688	}
689	}
690	}
691	)
692
693	//-----------------------------------------------------------------------------
694	// Debug
695	bool threading_enabled(void) __attribute__((const)) {
696	return true;
697	}
698
699	//-----------------------------------------------------------------------------
700	// Statistics
701	#if !defined(__CFA_NO_STATISTICS__)
702	void print_halts( processor & this ) {
703	this.print_halts = true;
704	}
705	#endif
706	// Local Variables: //
707	// mode: c //
708	// tab-width: 4 //
709	// End: //

Note: See TracBrowser for help on using the repository browser.

Download in other formats:

Original Format