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kernel.cfa @ ab5498ec

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

Last change on this file since ab5498ec was 55d6affb, checked in by Thierry Delisle <tdelisle@…>, 4 years ago
Fixed stupid copy past mistake where I used eventfd_read (wait) instead of eventfd_write (signal).
Property mode set to `100644`
File size: 23.9 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	extern "C" {
25	#include <sys/eventfd.h>
26	}
27
28	//CFA Includes
29	#include "kernel_private.hfa"
30	#include "preemption.hfa"
31
32	//Private includes
33	#define __CFA_INVOKE_PRIVATE__
34	#include "invoke.h"
35
36
37	//-----------------------------------------------------------------------------
38	// Some assembly required
39	#if defined( __i386 )
40	// mxcr : SSE Status and Control bits (control bits are preserved across function calls)
41	// fcw : X87 FPU control word (preserved across function calls)
42	#define __x87_store \
43	uint32_t __mxcr; \
44	uint16_t __fcw; \
45	__asm__ volatile ( \
46	"stmxcsr %0\n" \
47	"fnstcw %1\n" \
48	: "=m" (__mxcr),\
49	"=m" (__fcw) \
50	)
51
52	#define __x87_load \
53	__asm__ volatile ( \
54	"fldcw %1\n" \
55	"ldmxcsr %0\n" \
56	::"m" (__mxcr),\
57	"m" (__fcw) \
58	)
59
60	#elif defined( __x86_64 )
61	#define __x87_store \
62	uint32_t __mxcr; \
63	uint16_t __fcw; \
64	__asm__ volatile ( \
65	"stmxcsr %0\n" \
66	"fnstcw %1\n" \
67	: "=m" (__mxcr),\
68	"=m" (__fcw) \
69	)
70
71	#define __x87_load \
72	__asm__ volatile ( \
73	"fldcw %1\n" \
74	"ldmxcsr %0\n" \
75	:: "m" (__mxcr),\
76	"m" (__fcw) \
77	)
78
79	#elif defined( __arm__ )
80	#define __x87_store
81	#define __x87_load
82
83	#elif defined( __aarch64__ )
84	#define __x87_store \
85	uint32_t __fpcntl[2]; \
86	__asm__ volatile ( \
87	"mrs x9, FPCR\n" \
88	"mrs x10, FPSR\n" \
89	"stp x9, x10, %0\n" \
90	: "=m" (__fpcntl) : : "x9", "x10" \
91	)
92
93	#define __x87_load \
94	__asm__ volatile ( \
95	"ldp x9, x10, %0\n" \
96	"msr FPSR, x10\n" \
97	"msr FPCR, x9\n" \
98	: "=m" (__fpcntl) : : "x9", "x10" \
99	)
100
101	#else
102	#error unsupported hardware architecture
103	#endif
104
105	extern $thread * mainThread;
106	extern processor * mainProcessor;
107
108	//-----------------------------------------------------------------------------
109	// Kernel Scheduling logic
110	static $thread * __next_thread(cluster * this);
111	static $thread * __next_thread_slow(cluster * this);
112	static void __run_thread(processor * this, $thread * dst);
113	static void __wake_one(cluster * cltr);
114
115	static void push (__cluster_idles & idles, processor & proc);
116	static void remove(__cluster_idles & idles, processor & proc);
117	static [unsigned idle, unsigned total, * processor] query( & __cluster_idles idles );
118
119	extern void __cfa_io_start( processor * );
120	extern void __cfa_io_drain( processor * );
121	extern void __cfa_io_flush( processor * );
122	extern void __cfa_io_stop ( processor * );
123	static inline void __maybe_io_drain( processor * );
124
125	extern void __disable_interrupts_hard();
126	extern void __enable_interrupts_hard();
127
128	//=============================================================================================
129	// Kernel Scheduling logic
130	//=============================================================================================
131	//Main of the processor contexts
132	void main(processorCtx_t & runner) {
133	// Because of a bug, we couldn't initialized the seed on construction
134	// Do it here
135	__cfaabi_tls.rand_seed ^= rdtscl();
136	__cfaabi_tls.ready_rng.fwd_seed = 25214903917_l64u * (rdtscl() ^ (uintptr_t)&runner);
137	__tls_rand_advance_bck();
138
139	processor * this = runner.proc;
140	verify(this);
141
142	__cfa_io_start( this );
143
144	__cfadbg_print_safe(runtime_core, "Kernel : core %p starting\n", this);
145	#if !defined(__CFA_NO_STATISTICS__)
146	if( this->print_halts ) {
147	__cfaabi_bits_print_safe( STDOUT_FILENO, "Processor : %d - %s (%p)\n", this->id, this->name, (void*)this);
148	}
149	#endif
150
151	{
152	// Setup preemption data
153	preemption_scope scope = { this };
154
155	#if !defined(__CFA_NO_STATISTICS__)
156	unsigned long long last_tally = rdtscl();
157	#endif
158
159
160	__cfadbg_print_safe(runtime_core, "Kernel : core %p started\n", this);
161
162	$thread * readyThread = 0p;
163	MAIN_LOOP:
164	for() {
165	// Check if there is pending io
166	__maybe_io_drain( this );
167
168	// Try to get the next thread
169	readyThread = __next_thread( this->cltr );
170
171	if( !readyThread ) {
172	__cfa_io_flush( this );
173	readyThread = __next_thread_slow( this->cltr );
174	}
175
176	HALT:
177	if( !readyThread ) {
178	// Don't block if we are done
179	if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
180
181	#if !defined(__CFA_NO_STATISTICS__)
182	__tls_stats()->ready.sleep.halts++;
183	#endif
184
185	// Push self to idle stack
186	push(this->cltr->idles, * this);
187
188	// Confirm the ready-queue is empty
189	readyThread = __next_thread_slow( this->cltr );
190	if( readyThread ) {
191	// A thread was found, cancel the halt
192	remove(this->cltr->idles, * this);
193
194	#if !defined(__CFA_NO_STATISTICS__)
195	__tls_stats()->ready.sleep.cancels++;
196	#endif
197
198	// continue the mai loop
199	break HALT;
200	}
201
202	#if !defined(__CFA_NO_STATISTICS__)
203	if(this->print_halts) {
204	__cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 0\n", this->id, rdtscl());
205	}
206	#endif
207
208	__cfadbg_print_safe(runtime_core, "Kernel : core %p waiting on eventfd %d\n", this, this->idle);
209
210	__disable_interrupts_hard();
211	eventfd_t val;
212	eventfd_read( this->idle, &val );
213	__enable_interrupts_hard();
214
215	#if !defined(__CFA_NO_STATISTICS__)
216	if(this->print_halts) {
217	__cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 1\n", this->id, rdtscl());
218	}
219	#endif
220
221	// We were woken up, remove self from idle
222	remove(this->cltr->idles, * this);
223
224	// DON'T just proceed, start looking again
225	continue MAIN_LOOP;
226	}
227
228	/* paranoid */ verify( readyThread );
229
230	// Reset io dirty bit
231	this->io.dirty = false;
232
233	// We found a thread run it
234	__run_thread(this, readyThread);
235
236	// Are we done?
237	if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
238
239	#if !defined(__CFA_NO_STATISTICS__)
240	unsigned long long curr = rdtscl();
241	if(curr > (last_tally + 500000000)) {
242	__tally_stats(this->cltr->stats, __cfaabi_tls.this_stats);
243	last_tally = curr;
244	}
245	#endif
246
247	if(this->io.pending && !this->io.dirty) {
248	__cfa_io_flush( this );
249	}
250	}
251
252	__cfadbg_print_safe(runtime_core, "Kernel : core %p stopping\n", this);
253	}
254
255	__cfa_io_stop( this );
256
257	post( this->terminated );
258
259
260	if(this == mainProcessor) {
261	// HACK : the coroutine context switch expects this_thread to be set
262	// and it make sense for it to be set in all other cases except here
263	// fake it
264	__cfaabi_tls.this_thread = mainThread;
265	}
266
267	__cfadbg_print_safe(runtime_core, "Kernel : core %p terminated\n", this);
268	}
269
270	static int * __volatile_errno() __attribute__((noinline));
271	static int * __volatile_errno() { asm(""); return &errno; }
272
273	// KERNEL ONLY
274	// runThread runs a thread by context switching
275	// from the processor coroutine to the target thread
276	static void __run_thread(processor * this, $thread * thrd_dst) {
277	/* paranoid */ verify( ! __preemption_enabled() );
278	/* paranoid */ verifyf( thrd_dst->state == Ready \|\| thrd_dst->preempted != __NO_PREEMPTION, "state : %d, preempted %d\n", thrd_dst->state, thrd_dst->preempted);
279	/* paranoid */ verifyf( thrd_dst->link.next == 0p, "Expected null got %p", thrd_dst->link.next );
280	__builtin_prefetch( thrd_dst->context.SP );
281
282	__cfadbg_print_safe(runtime_core, "Kernel : core %p running thread %p (%s)\n", this, thrd_dst, thrd_dst->self_cor.name);
283
284	$coroutine * proc_cor = get_coroutine(this->runner);
285
286	// set state of processor coroutine to inactive
287	verify(proc_cor->state == Active);
288	proc_cor->state = Blocked;
289
290	// Actually run the thread
291	RUNNING: while(true) {
292	thrd_dst->preempted = __NO_PREEMPTION;
293	thrd_dst->state = Active;
294
295	// Update global state
296	kernelTLS().this_thread = thrd_dst;
297
298	/* paranoid */ verify( ! __preemption_enabled() );
299	/* paranoid */ verify( kernelTLS().this_thread == thrd_dst );
300	/* paranoid */ verify( thrd_dst->curr_cluster == this->cltr );
301	/* paranoid */ verify( thrd_dst->context.SP );
302	/* paranoid */ verify( thrd_dst->state != Halted );
303	/* 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
304	/* 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
305	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_dst->canary );
306
307
308
309	// set context switch to the thread that the processor is executing
310	__cfactx_switch( &proc_cor->context, &thrd_dst->context );
311	// when __cfactx_switch returns we are back in the processor coroutine
312
313	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_dst->canary );
314	/* 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 );
315	/* 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 );
316	/* paranoid */ verify( thrd_dst->context.SP );
317	/* paranoid */ verify( thrd_dst->curr_cluster == this->cltr );
318	/* paranoid */ verify( kernelTLS().this_thread == thrd_dst );
319	/* paranoid */ verify( ! __preemption_enabled() );
320
321	// Reset global state
322	kernelTLS().this_thread = 0p;
323
324	// We just finished running a thread, there are a few things that could have happened.
325	// 1 - Regular case : the thread has blocked and now one has scheduled it yet.
326	// 2 - Racy case : the thread has blocked but someone has already tried to schedule it.
327	// 4 - Preempted
328	// In case 1, we may have won a race so we can't write to the state again.
329	// In case 2, we lost the race so we now own the thread.
330
331	if(unlikely(thrd_dst->preempted != __NO_PREEMPTION)) {
332	// The thread was preempted, reschedule it and reset the flag
333	__schedule_thread( thrd_dst );
334	break RUNNING;
335	}
336
337	if(unlikely(thrd_dst->state == Halting)) {
338	// The thread has halted, it should never be scheduled/run again
339	// finish the thread
340	__thread_finish( thrd_dst );
341	break RUNNING;
342	}
343
344	/* paranoid */ verify( thrd_dst->state == Active );
345	thrd_dst->state = Blocked;
346
347	// set state of processor coroutine to active and the thread to inactive
348	int old_ticket = __atomic_fetch_sub(&thrd_dst->ticket, 1, __ATOMIC_SEQ_CST);
349	switch(old_ticket) {
350	case TICKET_RUNNING:
351	// This is case 1, the regular case, nothing more is needed
352	break RUNNING;
353	case TICKET_UNBLOCK:
354	// This is case 2, the racy case, someone tried to run this thread before it finished blocking
355	// In this case, just run it again.
356	continue RUNNING;
357	default:
358	// This makes no sense, something is wrong abort
359	abort();
360	}
361	}
362
363	// Just before returning to the processor, set the processor coroutine to active
364	proc_cor->state = Active;
365
366	__cfadbg_print_safe(runtime_core, "Kernel : core %p finished running thread %p\n", this, thrd_dst);
367
368	/* paranoid */ verify( ! __preemption_enabled() );
369	}
370
371	// KERNEL_ONLY
372	void returnToKernel() {
373	/* paranoid */ verify( ! __preemption_enabled() );
374	$coroutine * proc_cor = get_coroutine(kernelTLS().this_processor->runner);
375	$thread * thrd_src = kernelTLS().this_thread;
376
377	#if !defined(__CFA_NO_STATISTICS__)
378	struct processor * last_proc = kernelTLS().this_processor;
379	#endif
380
381	// Run the thread on this processor
382	{
383	int local_errno = *__volatile_errno();
384	#if defined( __i386 ) \|\| defined( __x86_64 )
385	__x87_store;
386	#endif
387	/* paranoid */ verify( proc_cor->context.SP );
388	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_src->canary );
389	__cfactx_switch( &thrd_src->context, &proc_cor->context );
390	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_src->canary );
391	#if defined( __i386 ) \|\| defined( __x86_64 )
392	__x87_load;
393	#endif
394	*__volatile_errno() = local_errno;
395	}
396
397	#if !defined(__CFA_NO_STATISTICS__)
398	if(last_proc != kernelTLS().this_processor) {
399	__tls_stats()->ready.threads.migration++;
400	}
401	#endif
402
403	/* paranoid */ verify( ! __preemption_enabled() );
404	/* 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 );
405	/* 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 );
406	}
407
408	//-----------------------------------------------------------------------------
409	// Scheduler routines
410	// KERNEL ONLY
411	void __schedule_thread( $thread * thrd ) {
412	/* paranoid */ verify( ! __preemption_enabled() );
413	/* paranoid */ verify( kernelTLS().this_proc_id );
414	/* paranoid */ verify( thrd );
415	/* paranoid */ verify( thrd->state != Halted );
416	/* paranoid */ verify( thrd->curr_cluster );
417	/* paranoid */ #if defined( __CFA_WITH_VERIFY__ )
418	/* paranoid */ if( thrd->state == Blocked \|\| thrd->state == Start ) assertf( thrd->preempted == __NO_PREEMPTION,
419	"Error inactive thread marked as preempted, state %d, preemption %d\n", thrd->state, thrd->preempted );
420	/* paranoid */ if( thrd->preempted != __NO_PREEMPTION ) assertf(thrd->state == Active,
421	"Error preempted thread marked as not currently running, state %d, preemption %d\n", thrd->state, thrd->preempted );
422	/* paranoid */ #endif
423	/* paranoid */ verifyf( thrd->link.next == 0p, "Expected null got %p", thrd->link.next );
424	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd->canary );
425
426
427	if (thrd->preempted == __NO_PREEMPTION) thrd->state = Ready;
428
429	ready_schedule_lock();
430	// Dereference the thread now because once we push it, there is not guaranteed it's still valid.
431	struct cluster * cl = thrd->curr_cluster;
432
433	// push the thread to the cluster ready-queue
434	push( cl, thrd );
435
436	// variable thrd is no longer safe to use
437
438	// wake the cluster using the save variable.
439	__wake_one( cl );
440	ready_schedule_unlock();
441
442	/* paranoid */ verify( ! __preemption_enabled() );
443	}
444
445	// KERNEL ONLY
446	static inline $thread * __next_thread(cluster * this) with( *this ) {
447	/* paranoid */ verify( ! __preemption_enabled() );
448	/* paranoid */ verify( kernelTLS().this_proc_id );
449
450	ready_schedule_lock();
451	$thread * thrd = pop( this );
452	ready_schedule_unlock();
453
454	/* paranoid */ verify( kernelTLS().this_proc_id );
455	/* paranoid */ verify( ! __preemption_enabled() );
456	return thrd;
457	}
458
459	// KERNEL ONLY
460	static inline $thread * __next_thread_slow(cluster * this) with( *this ) {
461	/* paranoid */ verify( ! __preemption_enabled() );
462	/* paranoid */ verify( kernelTLS().this_proc_id );
463
464	ready_schedule_lock();
465	$thread * thrd = pop_slow( this );
466	ready_schedule_unlock();
467
468	/* paranoid */ verify( kernelTLS().this_proc_id );
469	/* paranoid */ verify( ! __preemption_enabled() );
470	return thrd;
471	}
472
473	void unpark( $thread * thrd ) {
474	if( !thrd ) return;
475
476	int old_ticket = __atomic_fetch_add(&thrd->ticket, 1, __ATOMIC_SEQ_CST);
477	switch(old_ticket) {
478	case TICKET_RUNNING:
479	// Wake won the race, the thread will reschedule/rerun itself
480	break;
481	case TICKET_BLOCKED:
482	/* paranoid */ verify( ! thrd->preempted != __NO_PREEMPTION );
483	/* paranoid */ verify( thrd->state == Blocked );
484
485	{
486	/* paranoid */ verify( publicTLS_get(this_proc_id) );
487	bool full = publicTLS_get(this_proc_id)->full_proc;
488	if(full) disable_interrupts();
489
490	/* paranoid */ verify( ! __preemption_enabled() );
491
492	// Wake lost the race,
493	__schedule_thread( thrd );
494
495	/* paranoid */ verify( ! __preemption_enabled() );
496
497	if(full) enable_interrupts( __cfaabi_dbg_ctx );
498	/* paranoid */ verify( publicTLS_get(this_proc_id) );
499	}
500
501	break;
502	default:
503	// This makes no sense, something is wrong abort
504	abort("Thread %p (%s) has mismatch park/unpark\n", thrd, thrd->self_cor.name);
505	}
506	}
507
508	void park( void ) {
509	/* paranoid */ verify( __preemption_enabled() );
510	disable_interrupts();
511	/* paranoid */ verify( ! __preemption_enabled() );
512	/* paranoid */ verify( kernelTLS().this_thread->preempted == __NO_PREEMPTION );
513
514	returnToKernel();
515
516	/* paranoid */ verify( ! __preemption_enabled() );
517	enable_interrupts( __cfaabi_dbg_ctx );
518	/* paranoid */ verify( __preemption_enabled() );
519
520	}
521
522	extern "C" {
523	// Leave the thread monitor
524	// last routine called by a thread.
525	// Should never return
526	void __cfactx_thrd_leave() {
527	$thread * thrd = active_thread();
528	$monitor * this = &thrd->self_mon;
529
530	// Lock the monitor now
531	lock( this->lock __cfaabi_dbg_ctx2 );
532
533	disable_interrupts();
534
535	/* paranoid */ verify( ! __preemption_enabled() );
536	/* paranoid */ verify( thrd->state == Active );
537	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd->canary );
538	/* paranoid */ verify( kernelTLS().this_thread == thrd );
539	/* paranoid */ verify( thrd->context.SP );
540	/* paranoid */ verifyf( ((uintptr_t)thrd->context.SP) > ((uintptr_t)__get_stack(thrd->curr_cor)->limit), "ERROR : $thread %p has been corrupted.\n StackPointer too large.\n", thrd );
541	/* paranoid */ verifyf( ((uintptr_t)thrd->context.SP) < ((uintptr_t)__get_stack(thrd->curr_cor)->base ), "ERROR : $thread %p has been corrupted.\n StackPointer too small.\n", thrd );
542
543	thrd->state = Halting;
544	if( TICKET_RUNNING != thrd->ticket ) { abort( "Thread terminated with pending unpark" ); }
545	if( thrd != this->owner ) { abort( "Thread internal monitor has incorrect owner" ); }
546	if( this->recursion != 1) { abort( "Thread internal monitor has unbalanced recursion" ); }
547
548	// Leave the thread
549	returnToKernel();
550
551	// Control flow should never reach here!
552	abort();
553	}
554	}
555
556	// KERNEL ONLY
557	bool force_yield( __Preemption_Reason reason ) {
558	/* paranoid */ verify( __preemption_enabled() );
559	disable_interrupts();
560	/* paranoid */ verify( ! __preemption_enabled() );
561
562	$thread * thrd = kernelTLS().this_thread;
563	/* paranoid */ verify(thrd->state == Active);
564
565	// SKULLDUGGERY: It is possible that we are preempting this thread just before
566	// it was going to park itself. If that is the case and it is already using the
567	// intrusive fields then we can't use them to preempt the thread
568	// If that is the case, abandon the preemption.
569	bool preempted = false;
570	if(thrd->link.next == 0p) {
571	preempted = true;
572	thrd->preempted = reason;
573	returnToKernel();
574	}
575
576	/* paranoid */ verify( ! __preemption_enabled() );
577	enable_interrupts_noPoll();
578	/* paranoid */ verify( __preemption_enabled() );
579
580	return preempted;
581	}
582
583	//=============================================================================================
584	// Kernel Idle Sleep
585	//=============================================================================================
586	// Wake a thread from the front if there are any
587	static void __wake_one(cluster * this) {
588	/* paranoid */ verify( ! __preemption_enabled() );
589	/* paranoid */ verify( ready_schedule_islocked() );
590
591	// Check if there is a sleeping processor
592	processor * p;
593	unsigned idle;
594	unsigned total;
595	[idle, total, p] = query(this->idles);
596
597	// If no one is sleeping, we are done
598	if( idle == 0 ) return;
599
600	// We found a processor, wake it up
601	eventfd_t val;
602	val = 1;
603	eventfd_write( p->idle, val );
604
605	#if !defined(__CFA_NO_STATISTICS__)
606	__tls_stats()->ready.sleep.wakes++;
607	#endif
608
609	/* paranoid */ verify( ready_schedule_islocked() );
610	/* paranoid */ verify( ! __preemption_enabled() );
611
612	return;
613	}
614
615	// Unconditionnaly wake a thread
616	void __wake_proc(processor * this) {
617	__cfadbg_print_safe(runtime_core, "Kernel : waking Processor %p\n", this);
618
619	disable_interrupts();
620	/* paranoid */ verify( ! __preemption_enabled() );
621	eventfd_t val;
622	val = 1;
623	eventfd_write( this->idle, val );
624	enable_interrupts( __cfaabi_dbg_ctx );
625	}
626
627	static void push (__cluster_idles & this, processor & proc) {
628	/* paranoid */ verify( ! __preemption_enabled() );
629	lock( this );
630	this.idle++;
631	/* paranoid */ verify( this.idle <= this.total );
632
633	insert_first(this.list, proc);
634	unlock( this );
635	/* paranoid */ verify( ! __preemption_enabled() );
636	}
637
638	static void remove(__cluster_idles & this, processor & proc) {
639	/* paranoid */ verify( ! __preemption_enabled() );
640	lock( this );
641	this.idle--;
642	/* paranoid */ verify( this.idle >= 0 );
643
644	remove(proc);
645	unlock( this );
646	/* paranoid */ verify( ! __preemption_enabled() );
647	}
648
649	static [unsigned idle, unsigned total, * processor] query( & __cluster_idles this ) {
650	for() {
651	uint64_t l = __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST);
652	if( 1 == (l % 2) ) { Pause(); continue; }
653	unsigned idle = this.idle;
654	unsigned total = this.total;
655	processor * proc = &this.list`first;
656	// Compiler fence is unnecessary, but gcc-8 and older incorrectly reorder code without it
657	asm volatile("": : :"memory");
658	if(l != __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST)) { Pause(); continue; }
659	return [idle, total, proc];
660	}
661	}
662
663	//=============================================================================================
664	// Unexpected Terminating logic
665	//=============================================================================================
666	void __kernel_abort_msg( char * abort_text, int abort_text_size ) {
667	$thread * thrd = __cfaabi_tls.this_thread;
668
669	if(thrd) {
670	int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
671	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
672
673	if ( &thrd->self_cor != thrd->curr_cor ) {
674	len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
675	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
676	}
677	else {
678	__cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
679	}
680	}
681	else {
682	int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
683	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
684	}
685	}
686
687	int __kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
688	return get_coroutine(__cfaabi_tls.this_thread) == get_coroutine(mainThread) ? 4 : 2;
689	}
690
691	static __spinlock_t kernel_debug_lock;
692
693	extern "C" {
694	void __cfaabi_bits_acquire() {
695	lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
696	}
697
698	void __cfaabi_bits_release() {
699	unlock( kernel_debug_lock );
700	}
701	}
702
703	//=============================================================================================
704	// Kernel Utilities
705	//=============================================================================================
706	#if defined(CFA_HAVE_LINUX_IO_URING_H)
707	#include "io/types.hfa"
708	#endif
709
710	static inline void __maybe_io_drain( processor * proc ) {
711	#if defined(CFA_HAVE_LINUX_IO_URING_H)
712	__cfadbg_print_safe(runtime_core, "Kernel : core %p checking io for ring %d\n", proc, proc->io.ctx->fd);
713
714	// Check if we should drain the queue
715	$io_context * ctx = proc->io.ctx;
716	unsigned head = *ctx->cq.head;
717	unsigned tail = *ctx->cq.tail;
718	if(head != tail) __cfa_io_drain( proc );
719	#endif
720	}
721
722	//-----------------------------------------------------------------------------
723	// Debug
724	__cfaabi_dbg_debug_do(
725	extern "C" {
726	void __cfaabi_dbg_record_lock(__spinlock_t & this, const char prev_name[]) {
727	this.prev_name = prev_name;
728	this.prev_thrd = kernelTLS().this_thread;
729	}
730	}
731	)
732
733	//-----------------------------------------------------------------------------
734	// Debug
735	bool threading_enabled(void) __attribute__((const)) {
736	return true;
737	}
738
739	//-----------------------------------------------------------------------------
740	// Statistics
741	#if !defined(__CFA_NO_STATISTICS__)
742	void print_halts( processor & this ) {
743	this.print_halts = true;
744	}
745
746	void print_stats_now( cluster & this, int flags ) {
747	__print_stats( this.stats, this.print_stats, "Cluster", this.name, (void*)&this );
748	}
749
750	extern int __print_alarm_stats;
751	void print_alarm_stats() {
752	__print_alarm_stats = -1;
753	}
754	#endif
755	// Local Variables: //
756	// mode: c //
757	// tab-width: 4 //
758	// End: //

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