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kernel.cfa @ 0190480

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

Last change on this file since 0190480 was 0190480, checked in by Peter A. Buhr <pabuhr@…>, 4 years ago
update for 32-bit ARM
Property mode set to `100644`
File size: 22.6 KB

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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 : Mon Aug 31 07:08:20 2020
13	// Update Count : 71
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	#elif defined( __arm__ )
77	#define __x87_store
78	#define __x87_load
79
80	#elif defined( __aarch64__ )
81	#define __x87_store \
82	uint32_t __fpcntl[2]; \
83	__asm__ volatile ( \
84	"mrs x9, FPCR\n" \
85	"mrs x10, FPSR\n" \
86	"stp x9, x10, %0\n" \
87	: "=m" (__fpcntl) : : "x9", "x10" \
88	)
89
90	#define __x87_load \
91	__asm__ volatile ( \
92	"ldp x9, x10, %0\n" \
93	"msr FPSR, x10\n" \
94	"msr FPCR, x9\n" \
95	: "=m" (__fpcntl) : : "x9", "x10" \
96	)
97
98	#else
99	#error unsupported hardware architecture
100	#endif
101
102	extern $thread * mainThread;
103	extern processor * mainProcessor;
104
105	//-----------------------------------------------------------------------------
106	// Kernel Scheduling logic
107	static $thread * __next_thread(cluster * this);
108	static $thread * __next_thread_slow(cluster * this);
109	static void __run_thread(processor * this, $thread * dst);
110	static void __wake_one(struct __processor_id_t * id, cluster * cltr);
111
112	static void push (__cluster_idles & idles, processor & proc);
113	static void remove(__cluster_idles & idles, processor & proc);
114	static [unsigned idle, unsigned total, * processor] query( & __cluster_idles idles );
115
116
117	//=============================================================================================
118	// Kernel Scheduling logic
119	//=============================================================================================
120	//Main of the processor contexts
121	void main(processorCtx_t & runner) {
122	// Because of a bug, we couldn't initialized the seed on construction
123	// Do it here
124	kernelTLS.rand_seed ^= rdtscl();
125	kernelTLS.ready_rng.fwd_seed = 25214903917_l64u * (rdtscl() ^ (uintptr_t)&runner);
126	__tls_rand_advance_bck();
127
128	processor * this = runner.proc;
129	verify(this);
130
131	__cfadbg_print_safe(runtime_core, "Kernel : core %p starting\n", this);
132	#if !defined(__CFA_NO_STATISTICS__)
133	if( this->print_halts ) {
134	__cfaabi_bits_print_safe( STDOUT_FILENO, "Processor : %d - %s (%p)\n", this->id, this->name, (void*)this);
135	}
136	#endif
137
138	{
139	// Setup preemption data
140	preemption_scope scope = { this };
141
142	__cfadbg_print_safe(runtime_core, "Kernel : core %p started\n", this);
143
144	$thread * readyThread = 0p;
145	MAIN_LOOP:
146	for() {
147	// Try to get the next thread
148	readyThread = __next_thread( this->cltr );
149
150	if( !readyThread ) {
151	readyThread = __next_thread_slow( this->cltr );
152	}
153
154	HALT:
155	if( !readyThread ) {
156	// Don't block if we are done
157	if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
158
159	#if !defined(__CFA_NO_STATISTICS__)
160	__tls_stats()->ready.sleep.halts++;
161	#endif
162
163	// Push self to idle stack
164	push(this->cltr->idles, * this);
165
166	// Confirm the ready-queue is empty
167	readyThread = __next_thread_slow( this->cltr );
168	if( readyThread ) {
169	// A thread was found, cancel the halt
170	remove(this->cltr->idles, * this);
171
172	#if !defined(__CFA_NO_STATISTICS__)
173	__tls_stats()->ready.sleep.cancels++;
174	#endif
175
176	// continue the mai loop
177	break HALT;
178	}
179
180	#if !defined(__CFA_NO_STATISTICS__)
181	if(this->print_halts) {
182	__cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 0\n", this->id, rdtscl());
183	}
184	#endif
185
186	wait( this->idle );
187
188	#if !defined(__CFA_NO_STATISTICS__)
189	if(this->print_halts) {
190	__cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 1\n", this->id, rdtscl());
191	}
192	#endif
193
194	// We were woken up, remove self from idle
195	remove(this->cltr->idles, * this);
196
197	// DON'T just proceed, start looking again
198	continue MAIN_LOOP;
199	}
200
201	/* paranoid */ verify( readyThread );
202
203	// We found a thread run it
204	__run_thread(this, readyThread);
205
206	// Are we done?
207	if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
208	}
209
210	__cfadbg_print_safe(runtime_core, "Kernel : core %p stopping\n", this);
211	}
212
213	V( this->terminated );
214
215	if(this == mainProcessor) {
216	// HACK : the coroutine context switch expects this_thread to be set
217	// and it make sense for it to be set in all other cases except here
218	// fake it
219	kernelTLS.this_thread = mainThread;
220	}
221
222	__cfadbg_print_safe(runtime_core, "Kernel : core %p terminated\n", this);
223	}
224
225	static int * __volatile_errno() __attribute__((noinline));
226	static int * __volatile_errno() { asm(""); return &errno; }
227
228	// KERNEL ONLY
229	// runThread runs a thread by context switching
230	// from the processor coroutine to the target thread
231	static void __run_thread(processor * this, $thread * thrd_dst) {
232	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
233	/* paranoid */ verifyf( thrd_dst->state == Ready \|\| thrd_dst->preempted != __NO_PREEMPTION, "state : %d, preempted %d\n", thrd_dst->state, thrd_dst->preempted);
234	/* paranoid */ verifyf( thrd_dst->link.next == 0p, "Expected null got %p", thrd_dst->link.next );
235	__builtin_prefetch( thrd_dst->context.SP );
236
237	$coroutine * proc_cor = get_coroutine(this->runner);
238
239	// Update global state
240	kernelTLS.this_thread = thrd_dst;
241
242	// set state of processor coroutine to inactive
243	verify(proc_cor->state == Active);
244	proc_cor->state = Blocked;
245
246	// Actually run the thread
247	RUNNING: while(true) {
248	thrd_dst->preempted = __NO_PREEMPTION;
249	thrd_dst->state = Active;
250
251	__cfaabi_dbg_debug_do(
252	thrd_dst->park_stale = true;
253	thrd_dst->unpark_stale = true;
254	)
255
256	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
257	/* paranoid */ verify( kernelTLS.this_thread == thrd_dst );
258	/* 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
259	/* 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
260
261	// set context switch to the thread that the processor is executing
262	verify( thrd_dst->context.SP );
263	__cfactx_switch( &proc_cor->context, &thrd_dst->context );
264	// when __cfactx_switch returns we are back in the processor coroutine
265
266	/* 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 );
267	/* 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 );
268	/* paranoid */ verify( kernelTLS.this_thread == thrd_dst );
269	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
270
271
272	// We just finished running a thread, there are a few things that could have happened.
273	// 1 - Regular case : the thread has blocked and now one has scheduled it yet.
274	// 2 - Racy case : the thread has blocked but someone has already tried to schedule it.
275	// 4 - Preempted
276	// In case 1, we may have won a race so we can't write to the state again.
277	// In case 2, we lost the race so we now own the thread.
278
279	if(unlikely(thrd_dst->preempted != __NO_PREEMPTION)) {
280	// The thread was preempted, reschedule it and reset the flag
281	__schedule_thread( (__processor_id_t*)this, thrd_dst );
282	break RUNNING;
283	}
284
285	if(unlikely(thrd_dst->state == Halted)) {
286	// The thread has halted, it should never be scheduled/run again
287	// We may need to wake someone up here since
288	unpark( this->destroyer __cfaabi_dbg_ctx2 );
289	this->destroyer = 0p;
290	break RUNNING;
291	}
292
293	/* paranoid */ verify( thrd_dst->state == Active );
294	thrd_dst->state = Blocked;
295
296	// set state of processor coroutine to active and the thread to inactive
297	int old_ticket = __atomic_fetch_sub(&thrd_dst->ticket, 1, __ATOMIC_SEQ_CST);
298	__cfaabi_dbg_debug_do( thrd_dst->park_result = old_ticket; )
299	switch(old_ticket) {
300	case 1:
301	// This is case 1, the regular case, nothing more is needed
302	break RUNNING;
303	case 2:
304	// This is case 2, the racy case, someone tried to run this thread before it finished blocking
305	// In this case, just run it again.
306	continue RUNNING;
307	default:
308	// This makes no sense, something is wrong abort
309	abort();
310	}
311	}
312
313	// Just before returning to the processor, set the processor coroutine to active
314	proc_cor->state = Active;
315	kernelTLS.this_thread = 0p;
316
317	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
318	}
319
320	// KERNEL_ONLY
321	void returnToKernel() {
322	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
323	$coroutine * proc_cor = get_coroutine(kernelTLS.this_processor->runner);
324	$thread * thrd_src = kernelTLS.this_thread;
325
326	#if !defined(__CFA_NO_STATISTICS__)
327	struct processor * last_proc = kernelTLS.this_processor;
328	#endif
329
330	// Run the thread on this processor
331	{
332	int local_errno = *__volatile_errno();
333	#if defined( __i386 ) \|\| defined( __x86_64 )
334	__x87_store;
335	#endif
336	verify( proc_cor->context.SP );
337	__cfactx_switch( &thrd_src->context, &proc_cor->context );
338	#if defined( __i386 ) \|\| defined( __x86_64 )
339	__x87_load;
340	#endif
341	*__volatile_errno() = local_errno;
342	}
343
344	#if !defined(__CFA_NO_STATISTICS__)
345	if(last_proc != kernelTLS.this_processor) {
346	__tls_stats()->ready.threads.migration++;
347	}
348	#endif
349
350	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
351	/* 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 );
352	/* 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 );
353	}
354
355	//-----------------------------------------------------------------------------
356	// Scheduler routines
357	// KERNEL ONLY
358	void __schedule_thread( struct __processor_id_t * id, $thread * thrd ) {
359	/* paranoid */ verify( thrd );
360	/* paranoid */ verify( thrd->state != Halted );
361	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
362	/* paranoid */ #if defined( __CFA_WITH_VERIFY__ )
363	/* paranoid */ if( thrd->state == Blocked \|\| thrd->state == Start ) assertf( thrd->preempted == __NO_PREEMPTION,
364	"Error inactive thread marked as preempted, state %d, preemption %d\n", thrd->state, thrd->preempted );
365	/* paranoid */ if( thrd->preempted != __NO_PREEMPTION ) assertf(thrd->state == Active,
366	"Error preempted thread marked as not currently running, state %d, preemption %d\n", thrd->state, thrd->preempted );
367	/* paranoid */ #endif
368	/* paranoid */ verifyf( thrd->link.next == 0p, "Expected null got %p", thrd->link.next );
369
370	if (thrd->preempted == __NO_PREEMPTION) thrd->state = Ready;
371
372	ready_schedule_lock ( id );
373	push( thrd->curr_cluster, thrd );
374	__wake_one(id, thrd->curr_cluster);
375	ready_schedule_unlock( id );
376
377	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
378	}
379
380	// KERNEL ONLY
381	static inline $thread * __next_thread(cluster * this) with( *this ) {
382	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
383
384	ready_schedule_lock ( (__processor_id_t*)kernelTLS.this_processor );
385	$thread * thrd = pop( this );
386	ready_schedule_unlock( (__processor_id_t*)kernelTLS.this_processor );
387
388	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
389	return thrd;
390	}
391
392	// KERNEL ONLY
393	static inline $thread * __next_thread_slow(cluster * this) with( *this ) {
394	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
395
396	ready_schedule_lock ( (__processor_id_t*)kernelTLS.this_processor );
397	$thread * thrd = pop_slow( this );
398	ready_schedule_unlock( (__processor_id_t*)kernelTLS.this_processor );
399
400	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
401	return thrd;
402	}
403
404	// KERNEL ONLY unpark with out disabling interrupts
405	void __unpark( struct __processor_id_t * id, $thread * thrd __cfaabi_dbg_ctx_param2 ) {
406	// record activity
407	__cfaabi_dbg_record_thrd( *thrd, false, caller );
408
409	int old_ticket = __atomic_fetch_add(&thrd->ticket, 1, __ATOMIC_SEQ_CST);
410	__cfaabi_dbg_debug_do( thrd->unpark_result = old_ticket; thrd->unpark_state = thrd->state; )
411	switch(old_ticket) {
412	case 1:
413	// Wake won the race, the thread will reschedule/rerun itself
414	break;
415	case 0:
416	/* paranoid */ verify( ! thrd->preempted != __NO_PREEMPTION );
417	/* paranoid */ verify( thrd->state == Blocked );
418
419	// Wake lost the race,
420	__schedule_thread( id, thrd );
421	break;
422	default:
423	// This makes no sense, something is wrong abort
424	abort();
425	}
426	}
427
428	void unpark( $thread * thrd __cfaabi_dbg_ctx_param2 ) {
429	if( !thrd ) return;
430
431	disable_interrupts();
432	__unpark( (__processor_id_t*)kernelTLS.this_processor, thrd __cfaabi_dbg_ctx_fwd2 );
433	enable_interrupts( __cfaabi_dbg_ctx );
434	}
435
436	void park( __cfaabi_dbg_ctx_param ) {
437	/* paranoid */ verify( kernelTLS.preemption_state.enabled );
438	disable_interrupts();
439	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
440	/* paranoid */ verify( kernelTLS.this_thread->preempted == __NO_PREEMPTION );
441
442	// record activity
443	__cfaabi_dbg_record_thrd( *kernelTLS.this_thread, true, caller );
444
445	returnToKernel();
446
447	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
448	enable_interrupts( __cfaabi_dbg_ctx );
449	/* paranoid */ verify( kernelTLS.preemption_state.enabled );
450
451	}
452
453	// KERNEL ONLY
454	void __leave_thread() {
455	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
456	returnToKernel();
457	abort();
458	}
459
460	// KERNEL ONLY
461	bool force_yield( __Preemption_Reason reason ) {
462	/* paranoid */ verify( kernelTLS.preemption_state.enabled );
463	disable_interrupts();
464	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
465
466	$thread * thrd = kernelTLS.this_thread;
467	/* paranoid */ verify(thrd->state == Active);
468
469	// SKULLDUGGERY: It is possible that we are preempting this thread just before
470	// it was going to park itself. If that is the case and it is already using the
471	// intrusive fields then we can't use them to preempt the thread
472	// If that is the case, abandon the preemption.
473	bool preempted = false;
474	if(thrd->link.next == 0p) {
475	preempted = true;
476	thrd->preempted = reason;
477	returnToKernel();
478	}
479
480	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
481	enable_interrupts_noPoll();
482	/* paranoid */ verify( kernelTLS.preemption_state.enabled );
483
484	return preempted;
485	}
486
487	//=============================================================================================
488	// Kernel Idle Sleep
489	//=============================================================================================
490	// Wake a thread from the front if there are any
491	static void __wake_one(struct __processor_id_t * id, cluster * this) {
492	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
493	/* paranoid */ verify( ready_schedule_islocked( id ) );
494
495	// Check if there is a sleeping processor
496	processor * p;
497	unsigned idle;
498	unsigned total;
499	[idle, total, p] = query(this->idles);
500
501	// If no one is sleeping, we are done
502	if( idle == 0 ) return;
503
504	// We found a processor, wake it up
505	post( p->idle );
506
507	#if !defined(__CFA_NO_STATISTICS__)
508	__tls_stats()->ready.sleep.wakes++;
509	#endif
510
511	/* paranoid */ verify( ready_schedule_islocked( id ) );
512	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
513
514	return;
515	}
516
517	// Unconditionnaly wake a thread
518	void __wake_proc(processor * this) {
519	__cfadbg_print_safe(runtime_core, "Kernel : waking Processor %p\n", this);
520
521	disable_interrupts();
522	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
523	bool ret = post( this->idle );
524	enable_interrupts( __cfaabi_dbg_ctx );
525	}
526
527	static void push (__cluster_idles & this, processor & proc) {
528	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
529	lock( this );
530	this.idle++;
531	/* paranoid */ verify( this.idle <= this.total );
532
533	insert_first(this.list, proc);
534	unlock( this );
535	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
536	}
537
538	static void remove(__cluster_idles & this, processor & proc) {
539	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
540	lock( this );
541	this.idle--;
542	/* paranoid */ verify( this.idle >= 0 );
543
544	remove(proc);
545	unlock( this );
546	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
547	}
548
549	static [unsigned idle, unsigned total, * processor] query( & __cluster_idles this ) {
550	for() {
551	uint64_t l = __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST);
552	if( 1 == (l % 2) ) { Pause(); continue; }
553	unsigned idle = this.idle;
554	unsigned total = this.total;
555	processor * proc = &this.list`first;
556	// Compiler fence is unnecessary, but gcc-8 and older incorrectly reorder code without it
557	asm volatile("": : :"memory");
558	if(l != __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST)) { Pause(); continue; }
559	return [idle, total, proc];
560	}
561	}
562
563	//=============================================================================================
564	// Unexpected Terminating logic
565	//=============================================================================================
566	static __spinlock_t kernel_abort_lock;
567	static bool kernel_abort_called = false;
568
569	void * kernel_abort(void) __attribute__ ((__nothrow__)) {
570	// abort cannot be recursively entered by the same or different processors because all signal handlers return when
571	// the globalAbort flag is true.
572	lock( kernel_abort_lock __cfaabi_dbg_ctx2 );
573
574	// first task to abort ?
575	if ( kernel_abort_called ) { // not first task to abort ?
576	unlock( kernel_abort_lock );
577
578	sigset_t mask;
579	sigemptyset( &mask );
580	sigaddset( &mask, SIGALRM ); // block SIGALRM signals
581	sigaddset( &mask, SIGUSR1 ); // block SIGALRM signals
582	sigsuspend( &mask ); // block the processor to prevent further damage during abort
583	_exit( EXIT_FAILURE ); // if processor unblocks before it is killed, terminate it
584	}
585	else {
586	kernel_abort_called = true;
587	unlock( kernel_abort_lock );
588	}
589
590	return kernelTLS.this_thread;
591	}
592
593	void kernel_abort_msg( void * kernel_data, char * abort_text, int abort_text_size ) {
594	$thread * thrd = ( $thread * ) kernel_data;
595
596	if(thrd) {
597	int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
598	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
599
600	if ( &thrd->self_cor != thrd->curr_cor ) {
601	len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
602	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
603	}
604	else {
605	__cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
606	}
607	}
608	else {
609	int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
610	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
611	}
612	}
613
614	int kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
615	return get_coroutine(kernelTLS.this_thread) == get_coroutine(mainThread) ? 4 : 2;
616	}
617
618	static __spinlock_t kernel_debug_lock;
619
620	extern "C" {
621	void __cfaabi_bits_acquire() {
622	lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
623	}
624
625	void __cfaabi_bits_release() {
626	unlock( kernel_debug_lock );
627	}
628	}
629
630	//=============================================================================================
631	// Kernel Utilities
632	//=============================================================================================
633	//-----------------------------------------------------------------------------
634	// Locks
635	void ?{}( semaphore & this, int count = 1 ) {
636	(this.lock){};
637	this.count = count;
638	(this.waiting){};
639	}
640	void ^?{}(semaphore & this) {}
641
642	bool P(semaphore & this) with( this ){
643	lock( lock __cfaabi_dbg_ctx2 );
644	count -= 1;
645	if ( count < 0 ) {
646	// queue current task
647	append( waiting, kernelTLS.this_thread );
648
649	// atomically release spin lock and block
650	unlock( lock );
651	park( __cfaabi_dbg_ctx );
652	return true;
653	}
654	else {
655	unlock( lock );
656	return false;
657	}
658	}
659
660	bool V(semaphore & this) with( this ) {
661	$thread * thrd = 0p;
662	lock( lock __cfaabi_dbg_ctx2 );
663	count += 1;
664	if ( count <= 0 ) {
665	// remove task at head of waiting list
666	thrd = pop_head( waiting );
667	}
668
669	unlock( lock );
670
671	// make new owner
672	unpark( thrd __cfaabi_dbg_ctx2 );
673
674	return thrd != 0p;
675	}
676
677	bool V(semaphore & this, unsigned diff) with( this ) {
678	$thread * thrd = 0p;
679	lock( lock __cfaabi_dbg_ctx2 );
680	int release = max(-count, (int)diff);
681	count += diff;
682	for(release) {
683	unpark( pop_head( waiting ) __cfaabi_dbg_ctx2 );
684	}
685
686	unlock( lock );
687
688	return thrd != 0p;
689	}
690
691	//-----------------------------------------------------------------------------
692	// Debug
693	__cfaabi_dbg_debug_do(
694	extern "C" {
695	void __cfaabi_dbg_record_lock(__spinlock_t & this, const char prev_name[]) {
696	this.prev_name = prev_name;
697	this.prev_thrd = kernelTLS.this_thread;
698	}
699
700	void __cfaabi_dbg_record_thrd($thread & this, bool park, const char prev_name[]) {
701	if(park) {
702	this.park_caller = prev_name;
703	this.park_stale = false;
704	}
705	else {
706	this.unpark_caller = prev_name;
707	this.unpark_stale = false;
708	}
709	}
710	}
711	)
712
713	//-----------------------------------------------------------------------------
714	// Debug
715	bool threading_enabled(void) __attribute__((const)) {
716	return true;
717	}
718
719	//-----------------------------------------------------------------------------
720	// Statistics
721	#if !defined(__CFA_NO_STATISTICS__)
722	void print_halts( processor & this ) {
723	this.print_halts = true;
724	}
725	#endif
726	// Local Variables: //
727	// mode: c //
728	// tab-width: 4 //
729	// End: //

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