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kernel.cfa @ 4e39f51

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

Last change on this file since 4e39f51 was 58d64a4, checked in by Thierry Delisle <tdelisle@…>, 4 years ago
processor_id_t now have a bool to state if it is a full processor. kernelTLS.this_thread now has much tighter lifetime. Remove warning in kernel.cfa
Property mode set to `100644`
File size: 22.6 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 : 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	// set state of processor coroutine to inactive
240	verify(proc_cor->state == Active);
241	proc_cor->state = Blocked;
242
243	// Actually run the thread
244	RUNNING: while(true) {
245	thrd_dst->preempted = __NO_PREEMPTION;
246	thrd_dst->state = Active;
247
248	__cfaabi_dbg_debug_do(
249	thrd_dst->park_stale = true;
250	thrd_dst->unpark_stale = true;
251	)
252	// Update global state
253	kernelTLS.this_thread = thrd_dst;
254
255	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
256	/* paranoid */ verify( kernelTLS.this_thread == thrd_dst );
257	/* 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
258	/* 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
259
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	// Reset global state
272	kernelTLS.this_thread = 0p;
273
274	// We just finished running a thread, there are a few things that could have happened.
275	// 1 - Regular case : the thread has blocked and now one has scheduled it yet.
276	// 2 - Racy case : the thread has blocked but someone has already tried to schedule it.
277	// 4 - Preempted
278	// In case 1, we may have won a race so we can't write to the state again.
279	// In case 2, we lost the race so we now own the thread.
280
281	if(unlikely(thrd_dst->preempted != __NO_PREEMPTION)) {
282	// The thread was preempted, reschedule it and reset the flag
283	__schedule_thread( (__processor_id_t*)this, thrd_dst );
284	break RUNNING;
285	}
286
287	if(unlikely(thrd_dst->state == Halted)) {
288	// The thread has halted, it should never be scheduled/run again
289	// We may need to wake someone up here since
290	unpark( this->destroyer __cfaabi_dbg_ctx2 );
291	this->destroyer = 0p;
292	break RUNNING;
293	}
294
295	/* paranoid */ verify( thrd_dst->state == Active );
296	thrd_dst->state = Blocked;
297
298	// set state of processor coroutine to active and the thread to inactive
299	int old_ticket = __atomic_fetch_sub(&thrd_dst->ticket, 1, __ATOMIC_SEQ_CST);
300	__cfaabi_dbg_debug_do( thrd_dst->park_result = old_ticket; )
301	switch(old_ticket) {
302	case 1:
303	// This is case 1, the regular case, nothing more is needed
304	break RUNNING;
305	case 2:
306	// This is case 2, the racy case, someone tried to run this thread before it finished blocking
307	// In this case, just run it again.
308	continue RUNNING;
309	default:
310	// This makes no sense, something is wrong abort
311	abort();
312	}
313	}
314
315	// Just before returning to the processor, set the processor coroutine to active
316	proc_cor->state = Active;
317
318	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
319	}
320
321	// KERNEL_ONLY
322	void returnToKernel() {
323	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
324	$coroutine * proc_cor = get_coroutine(kernelTLS.this_processor->runner);
325	$thread * thrd_src = kernelTLS.this_thread;
326
327	#if !defined(__CFA_NO_STATISTICS__)
328	struct processor * last_proc = kernelTLS.this_processor;
329	#endif
330
331	// Run the thread on this processor
332	{
333	int local_errno = *__volatile_errno();
334	#if defined( __i386 ) \|\| defined( __x86_64 )
335	__x87_store;
336	#endif
337	verify( proc_cor->context.SP );
338	__cfactx_switch( &thrd_src->context, &proc_cor->context );
339	#if defined( __i386 ) \|\| defined( __x86_64 )
340	__x87_load;
341	#endif
342	*__volatile_errno() = local_errno;
343	}
344
345	#if !defined(__CFA_NO_STATISTICS__)
346	if(last_proc != kernelTLS.this_processor) {
347	__tls_stats()->ready.threads.migration++;
348	}
349	#endif
350
351	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
352	/* 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 );
353	/* 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 );
354	}
355
356	//-----------------------------------------------------------------------------
357	// Scheduler routines
358	// KERNEL ONLY
359	void __schedule_thread( struct __processor_id_t * id, $thread * thrd ) {
360	/* paranoid */ verify( thrd );
361	/* paranoid */ verify( thrd->state != Halted );
362	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
363	/* paranoid */ #if defined( __CFA_WITH_VERIFY__ )
364	/* paranoid */ if( thrd->state == Blocked \|\| thrd->state == Start ) assertf( thrd->preempted == __NO_PREEMPTION,
365	"Error inactive thread marked as preempted, state %d, preemption %d\n", thrd->state, thrd->preempted );
366	/* paranoid */ if( thrd->preempted != __NO_PREEMPTION ) assertf(thrd->state == Active,
367	"Error preempted thread marked as not currently running, state %d, preemption %d\n", thrd->state, thrd->preempted );
368	/* paranoid */ #endif
369	/* paranoid */ verifyf( thrd->link.next == 0p, "Expected null got %p", thrd->link.next );
370
371	if (thrd->preempted == __NO_PREEMPTION) thrd->state = Ready;
372
373	ready_schedule_lock ( id );
374	push( thrd->curr_cluster, thrd );
375	__wake_one(id, thrd->curr_cluster);
376	ready_schedule_unlock( id );
377
378	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
379	}
380
381	// KERNEL ONLY
382	static inline $thread * __next_thread(cluster * this) with( *this ) {
383	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
384
385	ready_schedule_lock ( (__processor_id_t*)kernelTLS.this_processor );
386	$thread * thrd = pop( this );
387	ready_schedule_unlock( (__processor_id_t*)kernelTLS.this_processor );
388
389	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
390	return thrd;
391	}
392
393	// KERNEL ONLY
394	static inline $thread * __next_thread_slow(cluster * this) with( *this ) {
395	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
396
397	ready_schedule_lock ( (__processor_id_t*)kernelTLS.this_processor );
398	$thread * thrd = pop_slow( this );
399	ready_schedule_unlock( (__processor_id_t*)kernelTLS.this_processor );
400
401	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
402	return thrd;
403	}
404
405	// KERNEL ONLY unpark with out disabling interrupts
406	void __unpark( struct __processor_id_t * id, $thread * thrd __cfaabi_dbg_ctx_param2 ) {
407	// record activity
408	__cfaabi_dbg_record_thrd( *thrd, false, caller );
409
410	int old_ticket = __atomic_fetch_add(&thrd->ticket, 1, __ATOMIC_SEQ_CST);
411	__cfaabi_dbg_debug_do( thrd->unpark_result = old_ticket; thrd->unpark_state = thrd->state; )
412	switch(old_ticket) {
413	case 1:
414	// Wake won the race, the thread will reschedule/rerun itself
415	break;
416	case 0:
417	/* paranoid */ verify( ! thrd->preempted != __NO_PREEMPTION );
418	/* paranoid */ verify( thrd->state == Blocked );
419
420	// Wake lost the race,
421	__schedule_thread( id, thrd );
422	break;
423	default:
424	// This makes no sense, something is wrong abort
425	abort();
426	}
427	}
428
429	void unpark( $thread * thrd __cfaabi_dbg_ctx_param2 ) {
430	if( !thrd ) return;
431
432	disable_interrupts();
433	__unpark( (__processor_id_t*)kernelTLS.this_processor, thrd __cfaabi_dbg_ctx_fwd2 );
434	enable_interrupts( __cfaabi_dbg_ctx );
435	}
436
437	void park( __cfaabi_dbg_ctx_param ) {
438	/* paranoid */ verify( kernelTLS.preemption_state.enabled );
439	disable_interrupts();
440	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
441	/* paranoid */ verify( kernelTLS.this_thread->preempted == __NO_PREEMPTION );
442
443	// record activity
444	__cfaabi_dbg_record_thrd( *kernelTLS.this_thread, true, caller );
445
446	returnToKernel();
447
448	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
449	enable_interrupts( __cfaabi_dbg_ctx );
450	/* paranoid */ verify( kernelTLS.preemption_state.enabled );
451
452	}
453
454	// KERNEL ONLY
455	void __leave_thread() {
456	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
457	returnToKernel();
458	abort();
459	}
460
461	// KERNEL ONLY
462	bool force_yield( __Preemption_Reason reason ) {
463	/* paranoid */ verify( kernelTLS.preemption_state.enabled );
464	disable_interrupts();
465	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
466
467	$thread * thrd = kernelTLS.this_thread;
468	/* paranoid */ verify(thrd->state == Active);
469
470	// SKULLDUGGERY: It is possible that we are preempting this thread just before
471	// it was going to park itself. If that is the case and it is already using the
472	// intrusive fields then we can't use them to preempt the thread
473	// If that is the case, abandon the preemption.
474	bool preempted = false;
475	if(thrd->link.next == 0p) {
476	preempted = true;
477	thrd->preempted = reason;
478	returnToKernel();
479	}
480
481	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
482	enable_interrupts_noPoll();
483	/* paranoid */ verify( kernelTLS.preemption_state.enabled );
484
485	return preempted;
486	}
487
488	//=============================================================================================
489	// Kernel Idle Sleep
490	//=============================================================================================
491	// Wake a thread from the front if there are any
492	static void __wake_one(struct __processor_id_t * id, cluster * this) {
493	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
494	/* paranoid */ verify( ready_schedule_islocked( id ) );
495
496	// Check if there is a sleeping processor
497	processor * p;
498	unsigned idle;
499	unsigned total;
500	[idle, total, p] = query(this->idles);
501
502	// If no one is sleeping, we are done
503	if( idle == 0 ) return;
504
505	// We found a processor, wake it up
506	post( p->idle );
507
508	#if !defined(__CFA_NO_STATISTICS__)
509	__tls_stats()->ready.sleep.wakes++;
510	#endif
511
512	/* paranoid */ verify( ready_schedule_islocked( id ) );
513	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
514
515	return;
516	}
517
518	// Unconditionnaly wake a thread
519	void __wake_proc(processor * this) {
520	__cfadbg_print_safe(runtime_core, "Kernel : waking Processor %p\n", this);
521
522	disable_interrupts();
523	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
524	post( this->idle );
525	enable_interrupts( __cfaabi_dbg_ctx );
526	}
527
528	static void push (__cluster_idles & this, processor & proc) {
529	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
530	lock( this );
531	this.idle++;
532	/* paranoid */ verify( this.idle <= this.total );
533
534	insert_first(this.list, proc);
535	unlock( this );
536	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
537	}
538
539	static void remove(__cluster_idles & this, processor & proc) {
540	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
541	lock( this );
542	this.idle--;
543	/* paranoid */ verify( this.idle >= 0 );
544
545	remove(proc);
546	unlock( this );
547	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
548	}
549
550	static [unsigned idle, unsigned total, * processor] query( & __cluster_idles this ) {
551	for() {
552	uint64_t l = __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST);
553	if( 1 == (l % 2) ) { Pause(); continue; }
554	unsigned idle = this.idle;
555	unsigned total = this.total;
556	processor * proc = &this.list`first;
557	// Compiler fence is unnecessary, but gcc-8 and older incorrectly reorder code without it
558	asm volatile("": : :"memory");
559	if(l != __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST)) { Pause(); continue; }
560	return [idle, total, proc];
561	}
562	}
563
564	//=============================================================================================
565	// Unexpected Terminating logic
566	//=============================================================================================
567	static __spinlock_t kernel_abort_lock;
568	static bool kernel_abort_called = false;
569
570	void * kernel_abort(void) __attribute__ ((__nothrow__)) {
571	// abort cannot be recursively entered by the same or different processors because all signal handlers return when
572	// the globalAbort flag is true.
573	lock( kernel_abort_lock __cfaabi_dbg_ctx2 );
574
575	// first task to abort ?
576	if ( kernel_abort_called ) { // not first task to abort ?
577	unlock( kernel_abort_lock );
578
579	sigset_t mask;
580	sigemptyset( &mask );
581	sigaddset( &mask, SIGALRM ); // block SIGALRM signals
582	sigaddset( &mask, SIGUSR1 ); // block SIGALRM signals
583	sigsuspend( &mask ); // block the processor to prevent further damage during abort
584	_exit( EXIT_FAILURE ); // if processor unblocks before it is killed, terminate it
585	}
586	else {
587	kernel_abort_called = true;
588	unlock( kernel_abort_lock );
589	}
590
591	return kernelTLS.this_thread;
592	}
593
594	void kernel_abort_msg( void * kernel_data, char * abort_text, int abort_text_size ) {
595	$thread * thrd = ( $thread * ) kernel_data;
596
597	if(thrd) {
598	int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
599	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
600
601	if ( &thrd->self_cor != thrd->curr_cor ) {
602	len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
603	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
604	}
605	else {
606	__cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
607	}
608	}
609	else {
610	int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
611	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
612	}
613	}
614
615	int kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
616	return get_coroutine(kernelTLS.this_thread) == get_coroutine(mainThread) ? 4 : 2;
617	}
618
619	static __spinlock_t kernel_debug_lock;
620
621	extern "C" {
622	void __cfaabi_bits_acquire() {
623	lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
624	}
625
626	void __cfaabi_bits_release() {
627	unlock( kernel_debug_lock );
628	}
629	}
630
631	//=============================================================================================
632	// Kernel Utilities
633	//=============================================================================================
634	//-----------------------------------------------------------------------------
635	// Locks
636	void ?{}( semaphore & this, int count = 1 ) {
637	(this.lock){};
638	this.count = count;
639	(this.waiting){};
640	}
641	void ^?{}(semaphore & this) {}
642
643	bool P(semaphore & this) with( this ){
644	lock( lock __cfaabi_dbg_ctx2 );
645	count -= 1;
646	if ( count < 0 ) {
647	// queue current task
648	append( waiting, kernelTLS.this_thread );
649
650	// atomically release spin lock and block
651	unlock( lock );
652	park( __cfaabi_dbg_ctx );
653	return true;
654	}
655	else {
656	unlock( lock );
657	return false;
658	}
659	}
660
661	bool V(semaphore & this) with( this ) {
662	$thread * thrd = 0p;
663	lock( lock __cfaabi_dbg_ctx2 );
664	count += 1;
665	if ( count <= 0 ) {
666	// remove task at head of waiting list
667	thrd = pop_head( waiting );
668	}
669
670	unlock( lock );
671
672	// make new owner
673	unpark( thrd __cfaabi_dbg_ctx2 );
674
675	return thrd != 0p;
676	}
677
678	bool V(semaphore & this, unsigned diff) with( this ) {
679	$thread * thrd = 0p;
680	lock( lock __cfaabi_dbg_ctx2 );
681	int release = max(-count, (int)diff);
682	count += diff;
683	for(release) {
684	unpark( pop_head( waiting ) __cfaabi_dbg_ctx2 );
685	}
686
687	unlock( lock );
688
689	return thrd != 0p;
690	}
691
692	//-----------------------------------------------------------------------------
693	// Debug
694	__cfaabi_dbg_debug_do(
695	extern "C" {
696	void __cfaabi_dbg_record_lock(__spinlock_t & this, const char prev_name[]) {
697	this.prev_name = prev_name;
698	this.prev_thrd = kernelTLS.this_thread;
699	}
700
701	void __cfaabi_dbg_record_thrd($thread & this, bool park, const char prev_name[]) {
702	if(park) {
703	this.park_caller = prev_name;
704	this.park_stale = false;
705	}
706	else {
707	this.unpark_caller = prev_name;
708	this.unpark_stale = false;
709	}
710	}
711	}
712	)
713
714	//-----------------------------------------------------------------------------
715	// Debug
716	bool threading_enabled(void) __attribute__((const)) {
717	return true;
718	}
719
720	//-----------------------------------------------------------------------------
721	// Statistics
722	#if !defined(__CFA_NO_STATISTICS__)
723	void print_halts( processor & this ) {
724	this.print_halts = true;
725	}
726	#endif
727	// Local Variables: //
728	// mode: c //
729	// tab-width: 4 //
730	// End: //

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