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Last change on this file since 5fe7322 was e67a82d, checked in by Peter A. Buhr <pabuhr@…>, 5 years ago
fix conflicts
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File size: 22.6 KB

Rev	Line
[8118303]	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
[75f3522]	10	// Created On : Tue Jan 17 12:27:26 2017
[6b0b624]	11	// Last Modified By : Peter A. Buhr
[74f5c83]	12	// Last Modified On : Fri Aug 14 15:23:00 2020
	13	// Update Count : 69
[8118303]	14	//
	15
[2026bb6]	16	#define __cforall_thread__
[4069faad]	17	// #define __CFA_DEBUG_PRINT_RUNTIME_CORE__
[2026bb6]	18
[8118303]	19	//C Includes
[214e8da]	20	#include <errno.h>
[9d944b2]	21	#include <stdio.h>
[58b6d1b]	22	#include <signal.h>
[9d944b2]	23	#include <unistd.h>
[8118303]	24
	25	//CFA Includes
[73abe95]	26	#include "kernel_private.hfa"
	27	#include "preemption.hfa"
[8118303]	28
	29	//Private includes
	30	#define __CFA_INVOKE_PRIVATE__
	31	#include "invoke.h"
	32
[4069faad]	33
[deca0f5]	34	//-----------------------------------------------------------------------------
	35	// Some assembly required
[1805b1b]	36	#if defined( __i386 )
[deca0f5]	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_ARCH )
[74f5c83]	77	#define __x87_store \
	78	uint32_t __fpcntl[2]; \
	79	__asm__ volatile ( \
	80	"mrs x9, FPCR\n" \
	81	"mrs x10, FPSR\n" \
	82	"stp x9, x10, %0\n" \
	83	: "=m" (__fpcntl) : : "x9", "x10" \
	84	)
	85
	86	#define __x87_load \
	87	__asm__ volatile ( \
	88	"ldp x9, x10, %0\n" \
	89	"msr FPSR, x10\n" \
	90	"msr FPCR, x9\n" \
	91	: "=m" (__fpcntl) : : "x9", "x10" \
	92	)
	93
[deca0f5]	94	#else
	95	#error unknown hardware architecture
	96	#endif
	97
[e660761]	98	extern $thread * mainThread;
	99	extern processor * mainProcessor;
[2ac095d]	100
[92e7631]	101	//-----------------------------------------------------------------------------
	102	// Kernel Scheduling logic
	103	static $thread * __next_thread(cluster * this);
[1eb239e4]	104	static $thread * __next_thread_slow(cluster * this);
[92e7631]	105	static void __run_thread(processor * this, $thread * dst);
[1eb239e4]	106	static void __wake_one(struct __processor_id_t * id, cluster * cltr);
	107
	108	static void push (__cluster_idles & idles, processor & proc);
	109	static void remove(__cluster_idles & idles, processor & proc);
	110	static [unsigned idle, unsigned total, * processor] query( & __cluster_idles idles );
	111
[c84e80a]	112
[75f3522]	113	//=============================================================================================
	114	// Kernel Scheduling logic
	115	//=============================================================================================
[8fcbb4c]	116	//Main of the processor contexts
[83a071f9]	117	void main(processorCtx_t & runner) {
[21184e3]	118	// Because of a bug, we couldn't initialized the seed on construction
	119	// Do it here
[7768b8d]	120	kernelTLS.rand_seed ^= rdtscl();
[f2384c9a]	121	kernelTLS.ready_rng.fwd_seed = 25214903917_l64u * (rdtscl() ^ (uintptr_t)&runner);
	122	__tls_rand_advance_bck();
[21184e3]	123
[83a071f9]	124	processor * this = runner.proc;
[094476d]	125	verify(this);
[c81ebf9]	126
[4069faad]	127	__cfadbg_print_safe(runtime_core, "Kernel : core %p starting\n", this);
[28d73c1]	128	#if !defined(__CFA_NO_STATISTICS__)
	129	if( this->print_halts ) {
	130	__cfaabi_bits_print_safe( STDOUT_FILENO, "Processor : %d - %s (%p)\n", this->id, this->name, (void*)this);
	131	}
	132	#endif
[b798713]	133
[75f3522]	134	{
[c81ebf9]	135	// Setup preemption data
	136	preemption_scope scope = { this };
	137
[4069faad]	138	__cfadbg_print_safe(runtime_core, "Kernel : core %p started\n", this);
[8118303]	139
[ac2b598]	140	$thread * readyThread = 0p;
[1eb239e4]	141	MAIN_LOOP:
	142	for() {
[92e7631]	143	// Try to get the next thread
[8c50aed]	144	readyThread = __next_thread( this->cltr );
[75f3522]	145
[1eb239e4]	146	if( !readyThread ) {
	147	readyThread = __next_thread_slow( this->cltr );
	148	}
[4e6fb8e]	149
[1eb239e4]	150	HALT:
	151	if( !readyThread ) {
	152	// Don't block if we are done
	153	if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
[c81ebf9]	154
[1eb239e4]	155	#if !defined(__CFA_NO_STATISTICS__)
	156	__tls_stats()->ready.sleep.halts++;
	157	#endif
[398e8e9]	158
[1eb239e4]	159	// Push self to idle stack
	160	push(this->cltr->idles, * this);
[398e8e9]	161
[1eb239e4]	162	// Confirm the ready-queue is empty
	163	readyThread = __next_thread_slow( this->cltr );
	164	if( readyThread ) {
	165	// A thread was found, cancel the halt
	166	remove(this->cltr->idles, * this);
	167
	168	#if !defined(__CFA_NO_STATISTICS__)
	169	__tls_stats()->ready.sleep.cancels++;
	170	#endif
	171
	172	// continue the mai loop
	173	break HALT;
	174	}
	175
	176	#if !defined(__CFA_NO_STATISTICS__)
	177	if(this->print_halts) {
	178	__cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 0\n", this->id, rdtscl());
	179	}
	180	#endif
	181
	182	wait( this->idle );
	183
	184	#if !defined(__CFA_NO_STATISTICS__)
	185	if(this->print_halts) {
	186	__cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 1\n", this->id, rdtscl());
	187	}
	188	#endif
	189
	190	// We were woken up, remove self from idle
	191	remove(this->cltr->idles, * this);
	192
	193	// DON'T just proceed, start looking again
	194	continue MAIN_LOOP;
[64a7146]	195	}
[1eb239e4]	196
	197	/* paranoid */ verify( readyThread );
	198
	199	// We found a thread run it
	200	__run_thread(this, readyThread);
	201
	202	// Are we done?
	203	if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
[c81ebf9]	204	}
	205
[4069faad]	206	__cfadbg_print_safe(runtime_core, "Kernel : core %p stopping\n", this);
[c84e80a]	207	}
[8118303]	208
[4cedd9f]	209	V( this->terminated );
[bdeba0b]	210
[28d73c1]	211	if(this == mainProcessor) {
[6a490b2]	212	// HACK : the coroutine context switch expects this_thread to be set
	213	// and it make sense for it to be set in all other cases except here
	214	// fake it
	215	kernelTLS.this_thread = mainThread;
	216	}
[7768b8d]	217
[4069faad]	218	__cfadbg_print_safe(runtime_core, "Kernel : core %p terminated\n", this);
[c84e80a]	219	}
	220
[5c1a531]	221	static int * __volatile_errno() __attribute__((noinline));
	222	static int * __volatile_errno() { asm(""); return &errno; }
	223
[14a61b5]	224	// KERNEL ONLY
[1c273d0]	225	// runThread runs a thread by context switching
	226	// from the processor coroutine to the target thread
[ac2b598]	227	static void __run_thread(processor * this, $thread * thrd_dst) {
[1eb239e4]	228	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
	229	/* paranoid */ verifyf( thrd_dst->state == Ready \|\| thrd_dst->preempted != __NO_PREEMPTION, "state : %d, preempted %d\n", thrd_dst->state, thrd_dst->preempted);
	230	/* paranoid */ verifyf( thrd_dst->link.next == 0p, "Expected null got %p", thrd_dst->link.next );
	231	__builtin_prefetch( thrd_dst->context.SP );
	232
[ac2b598]	233	$coroutine * proc_cor = get_coroutine(this->runner);
[8fcbb4c]	234
[14a61b5]	235	// Update global state
[e8e457e]	236	kernelTLS.this_thread = thrd_dst;
	237
[9f575ea]	238	// set state of processor coroutine to inactive
	239	verify(proc_cor->state == Active);
[ae7be7a]	240	proc_cor->state = Blocked;
[e8e457e]	241
[9f575ea]	242	// Actually run the thread
[3381ed7]	243	RUNNING: while(true) {
[ff79d5e]	244	thrd_dst->preempted = __NO_PREEMPTION;
	245	thrd_dst->state = Active;
[e8e457e]	246
[ae66348]	247	__cfaabi_dbg_debug_do(
[276ae57e]	248	thrd_dst->park_stale = true;
	249	thrd_dst->unpark_stale = true;
[ae66348]	250	)
[75f3522]	251
[3381ed7]	252	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
[a7b486b]	253	/* paranoid */ verify( kernelTLS.this_thread == thrd_dst );
[210b8b3]	254	/* 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
	255	/* 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
[3381ed7]	256
[9f575ea]	257	// set context switch to the thread that the processor is executing
	258	verify( thrd_dst->context.SP );
[c7a900a]	259	__cfactx_switch( &proc_cor->context, &thrd_dst->context );
	260	// when __cfactx_switch returns we are back in the processor coroutine
[9f575ea]	261
[210b8b3]	262	/* 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 );
	263	/* 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 );
[a7b486b]	264	/* paranoid */ verify( kernelTLS.this_thread == thrd_dst );
[3381ed7]	265	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
[75f3522]	266
[3381ed7]	267
	268	// We just finished running a thread, there are a few things that could have happened.
	269	// 1 - Regular case : the thread has blocked and now one has scheduled it yet.
	270	// 2 - Racy case : the thread has blocked but someone has already tried to schedule it.
	271	// 4 - Preempted
	272	// In case 1, we may have won a race so we can't write to the state again.
	273	// In case 2, we lost the race so we now own the thread.
	274
	275	if(unlikely(thrd_dst->preempted != __NO_PREEMPTION)) {
	276	// The thread was preempted, reschedule it and reset the flag
[9b1dcc2]	277	__schedule_thread( (__processor_id_t*)this, thrd_dst );
[3381ed7]	278	break RUNNING;
	279	}
[75f3522]	280
[ff79d5e]	281	if(unlikely(thrd_dst->state == Halted)) {
	282	// The thread has halted, it should never be scheduled/run again
	283	// We may need to wake someone up here since
	284	unpark( this->destroyer __cfaabi_dbg_ctx2 );
	285	this->destroyer = 0p;
	286	break RUNNING;
	287	}
	288
	289	/* paranoid */ verify( thrd_dst->state == Active );
	290	thrd_dst->state = Blocked;
	291
[3381ed7]	292	// set state of processor coroutine to active and the thread to inactive
[ff79d5e]	293	int old_ticket = __atomic_fetch_sub(&thrd_dst->ticket, 1, __ATOMIC_SEQ_CST);
	294	__cfaabi_dbg_debug_do( thrd_dst->park_result = old_ticket; )
	295	switch(old_ticket) {
	296	case 1:
[3381ed7]	297	// This is case 1, the regular case, nothing more is needed
	298	break RUNNING;
[ff79d5e]	299	case 2:
[3381ed7]	300	// This is case 2, the racy case, someone tried to run this thread before it finished blocking
	301	// In this case, just run it again.
	302	continue RUNNING;
	303	default:
	304	// This makes no sense, something is wrong abort
[ff79d5e]	305	abort();
[3381ed7]	306	}
[9f575ea]	307	}
[e8e457e]	308
[9f575ea]	309	// Just before returning to the processor, set the processor coroutine to active
[e8e457e]	310	proc_cor->state = Active;
[ae7be7a]	311	kernelTLS.this_thread = 0p;
[1eb239e4]	312
	313	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
[82c948c]	314	}
	315
[14a61b5]	316	// KERNEL_ONLY
[b0c7419]	317	void returnToKernel() {
[3381ed7]	318	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
[ac2b598]	319	$coroutine * proc_cor = get_coroutine(kernelTLS.this_processor->runner);
	320	$thread * thrd_src = kernelTLS.this_thread;
[e8e457e]	321
[29cb302]	322	#if !defined(__CFA_NO_STATISTICS__)
	323	struct processor * last_proc = kernelTLS.this_processor;
	324	#endif
	325
[9f575ea]	326	// Run the thread on this processor
	327	{
	328	int local_errno = *__volatile_errno();
	329	#if defined( __i386 ) \|\| defined( __x86_64 )
	330	__x87_store;
	331	#endif
	332	verify( proc_cor->context.SP );
[c7a900a]	333	__cfactx_switch( &thrd_src->context, &proc_cor->context );
[9f575ea]	334	#if defined( __i386 ) \|\| defined( __x86_64 )
	335	__x87_load;
	336	#endif
	337	*__volatile_errno() = local_errno;
[8fcbb4c]	338	}
[deca0f5]	339
[29cb302]	340	#if !defined(__CFA_NO_STATISTICS__)
	341	if(last_proc != kernelTLS.this_processor) {
	342	__tls_stats()->ready.threads.migration++;
	343	}
	344	#endif
	345
[3381ed7]	346	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
[210b8b3]	347	/* 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 );
	348	/* 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 );
[c84e80a]	349	}
	350
[8def349]	351	//-----------------------------------------------------------------------------
	352	// Scheduler routines
[14a61b5]	353	// KERNEL ONLY
[9b1dcc2]	354	void __schedule_thread( struct __processor_id_t * id, $thread * thrd ) {
[6a490b2]	355	/* paranoid */ verify( thrd );
	356	/* paranoid */ verify( thrd->state != Halted );
[9f575ea]	357	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
[3381ed7]	358	/* paranoid */ #if defined( __CFA_WITH_VERIFY__ )
[504a7dc]	359	/* paranoid */ if( thrd->state == Blocked \|\| thrd->state == Start ) assertf( thrd->preempted == __NO_PREEMPTION,
	360	"Error inactive thread marked as preempted, state %d, preemption %d\n", thrd->state, thrd->preempted );
[ff79d5e]	361	/* paranoid */ if( thrd->preempted != __NO_PREEMPTION ) assertf(thrd->state == Active,
[504a7dc]	362	"Error preempted thread marked as not currently running, state %d, preemption %d\n", thrd->state, thrd->preempted );
[3381ed7]	363	/* paranoid */ #endif
[6a490b2]	364	/* paranoid */ verifyf( thrd->link.next == 0p, "Expected null got %p", thrd->link.next );
[9f575ea]	365
[ae7be7a]	366	if (thrd->preempted == __NO_PREEMPTION) thrd->state = Ready;
[6b4cdd3]	367
[9b1dcc2]	368	ready_schedule_lock ( id );
[504a7dc]	369	push( thrd->curr_cluster, thrd );
[1eb239e4]	370	__wake_one(id, thrd->curr_cluster);
[9b1dcc2]	371	ready_schedule_unlock( id );
[1c273d0]	372
[9f575ea]	373	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
[db6f06a]	374	}
	375
[14a61b5]	376	// KERNEL ONLY
[1eb239e4]	377	static inline $thread * __next_thread(cluster * this) with( *this ) {
[3381ed7]	378	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
[7768b8d]	379
[9b1dcc2]	380	ready_schedule_lock ( (__processor_id_t*)kernelTLS.this_processor );
[1eb239e4]	381	$thread * thrd = pop( this );
[9b1dcc2]	382	ready_schedule_unlock( (__processor_id_t*)kernelTLS.this_processor );
[7768b8d]	383
[3381ed7]	384	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
[1eb239e4]	385	return thrd;
[eb2e723]	386	}
	387
[64a7146]	388	// KERNEL ONLY
[1eb239e4]	389	static inline $thread * __next_thread_slow(cluster * this) with( *this ) {
[64a7146]	390	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
	391
	392	ready_schedule_lock ( (__processor_id_t*)kernelTLS.this_processor );
[1eb239e4]	393	$thread * thrd = pop_slow( this );
[64a7146]	394	ready_schedule_unlock( (__processor_id_t*)kernelTLS.this_processor );
	395
	396	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
[1eb239e4]	397	return thrd;
[64a7146]	398	}
	399
[2d8f7b0]	400	// KERNEL ONLY unpark with out disabling interrupts
[9b1dcc2]	401	void __unpark( struct __processor_id_t * id, $thread * thrd __cfaabi_dbg_ctx_param2 ) {
[ae66348]	402	// record activity
	403	__cfaabi_dbg_record_thrd( *thrd, false, caller );
	404
[ff79d5e]	405	int old_ticket = __atomic_fetch_add(&thrd->ticket, 1, __ATOMIC_SEQ_CST);
	406	__cfaabi_dbg_debug_do( thrd->unpark_result = old_ticket; thrd->unpark_state = thrd->state; )
	407	switch(old_ticket) {
	408	case 1:
[3381ed7]	409	// Wake won the race, the thread will reschedule/rerun itself
	410	break;
[ff79d5e]	411	case 0:
[3381ed7]	412	/* paranoid */ verify( ! thrd->preempted != __NO_PREEMPTION );
[ff79d5e]	413	/* paranoid */ verify( thrd->state == Blocked );
[0b33412]	414
[3381ed7]	415	// Wake lost the race,
[9b1dcc2]	416	__schedule_thread( id, thrd );
[3381ed7]	417	break;
	418	default:
	419	// This makes no sense, something is wrong abort
	420	abort();
[de6319f]	421	}
[db6f06a]	422	}
	423
[2d8f7b0]	424	void unpark( $thread * thrd __cfaabi_dbg_ctx_param2 ) {
	425	if( !thrd ) return;
[db6f06a]	426
[82ff5845]	427	disable_interrupts();
[9b1dcc2]	428	__unpark( (__processor_id_t*)kernelTLS.this_processor, thrd __cfaabi_dbg_ctx_fwd2 );
[36982fc]	429	enable_interrupts( __cfaabi_dbg_ctx );
[eb2e723]	430	}
	431
[ae66348]	432	void park( __cfaabi_dbg_ctx_param ) {
[3381ed7]	433	/* paranoid */ verify( kernelTLS.preemption_state.enabled );
[82ff5845]	434	disable_interrupts();
[3381ed7]	435	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
	436	/* paranoid */ verify( kernelTLS.this_thread->preempted == __NO_PREEMPTION );
[0b33412]	437
[ae66348]	438	// record activity
	439	__cfaabi_dbg_record_thrd( *kernelTLS.this_thread, true, caller );
[0b33412]	440
[82c948c]	441	returnToKernel();
[0b33412]	442
[3381ed7]	443	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
[36982fc]	444	enable_interrupts( __cfaabi_dbg_ctx );
[3381ed7]	445	/* paranoid */ verify( kernelTLS.preemption_state.enabled );
[0c78741]	446
	447	}
[09800e9]	448
[3381ed7]	449	// KERNEL ONLY
[b0c7419]	450	void __leave_thread() {
[3381ed7]	451	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
[09800e9]	452	returnToKernel();
[b0c7419]	453	abort();
[09800e9]	454	}
	455
[14a61b5]	456	// KERNEL ONLY
[3381ed7]	457	bool force_yield( __Preemption_Reason reason ) {
	458	/* paranoid */ verify( kernelTLS.preemption_state.enabled );
[09800e9]	459	disable_interrupts();
[3381ed7]	460	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
[09800e9]	461
[ac2b598]	462	$thread * thrd = kernelTLS.this_thread;
[ff79d5e]	463	/* paranoid */ verify(thrd->state == Active);
[3381ed7]	464
	465	// SKULLDUGGERY: It is possible that we are preempting this thread just before
	466	// it was going to park itself. If that is the case and it is already using the
	467	// intrusive fields then we can't use them to preempt the thread
	468	// If that is the case, abandon the preemption.
	469	bool preempted = false;
[504a7dc]	470	if(thrd->link.next == 0p) {
[3381ed7]	471	preempted = true;
	472	thrd->preempted = reason;
	473	returnToKernel();
[de6319f]	474	}
[f2b12406]	475
[3381ed7]	476	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
	477	enable_interrupts_noPoll();
	478	/* paranoid */ verify( kernelTLS.preemption_state.enabled );
[f2b12406]	479
[3381ed7]	480	return preempted;
[f2b12406]	481	}
	482
[14a61b5]	483	//=============================================================================================
[92e7631]	484	// Kernel Idle Sleep
[14a61b5]	485	//=============================================================================================
[64a7146]	486	// Wake a thread from the front if there are any
[1eb239e4]	487	static void __wake_one(struct __processor_id_t * id, cluster * this) {
	488	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
[64a7146]	489	/* paranoid */ verify( ready_schedule_islocked( id ) );
[14a61b5]	490
[64a7146]	491	// Check if there is a sleeping processor
[1eb239e4]	492	processor * p;
	493	unsigned idle;
	494	unsigned total;
	495	[idle, total, p] = query(this->idles);
[14a61b5]	496
[64a7146]	497	// If no one is sleeping, we are done
[1eb239e4]	498	if( idle == 0 ) return;
[14a61b5]	499
[64a7146]	500	// We found a processor, wake it up
	501	post( p->idle );
[14a61b5]	502
[1eb239e4]	503	#if !defined(__CFA_NO_STATISTICS__)
	504	__tls_stats()->ready.sleep.wakes++;
	505	#endif
	506
	507	/* paranoid */ verify( ready_schedule_islocked( id ) );
	508	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
	509
	510	return;
[64a7146]	511	}
[14a61b5]	512
[64a7146]	513	// Unconditionnaly wake a thread
[1eb239e4]	514	void __wake_proc(processor * this) {
[64a7146]	515	__cfadbg_print_safe(runtime_core, "Kernel : waking Processor %p\n", this);
[14a61b5]	516
[64a7146]	517	disable_interrupts();
	518	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
	519	bool ret = post( this->idle );
	520	enable_interrupts( __cfaabi_dbg_ctx );
[92e7631]	521	}
	522
[1eb239e4]	523	static void push (__cluster_idles & this, processor & proc) {
	524	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
	525	lock( this );
	526	this.idle++;
	527	/* paranoid */ verify( this.idle <= this.total );
[8e16177]	528
[1eb239e4]	529	insert_first(this.list, proc);
	530	unlock( this );
	531	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
	532	}
[8e16177]	533
[1eb239e4]	534	static void remove(__cluster_idles & this, processor & proc) {
	535	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
	536	lock( this );
	537	this.idle--;
	538	/* paranoid */ verify( this.idle >= 0 );
[c34ebf2]	539
[1eb239e4]	540	remove(proc);
	541	unlock( this );
	542	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
	543	}
[c34ebf2]	544
[1eb239e4]	545	static [unsigned idle, unsigned total, * processor] query( & __cluster_idles this ) {
	546	for() {
	547	uint64_t l = __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST);
	548	if( 1 == (l % 2) ) { Pause(); continue; }
	549	unsigned idle = this.idle;
	550	unsigned total = this.total;
	551	processor * proc = &this.list`first;
[7fdae38]	552	// Compiler fence is unnecessary, but gcc-8 and older incorrectly reorder code without it
	553	asm volatile("": : :"memory");
[1eb239e4]	554	if(l != __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST)) { Pause(); continue; }
	555	return [idle, total, proc];
	556	}
[6b4cdd3]	557	}
	558
[dbe9b08]	559	//=============================================================================================
	560	// Unexpected Terminating logic
	561	//=============================================================================================
[ea7d2b0]	562	static __spinlock_t kernel_abort_lock;
[9d944b2]	563	static bool kernel_abort_called = false;
	564
[afd550c]	565	void * kernel_abort(void) __attribute__ ((__nothrow__)) {
[9d944b2]	566	// abort cannot be recursively entered by the same or different processors because all signal handlers return when
	567	// the globalAbort flag is true.
[36982fc]	568	lock( kernel_abort_lock __cfaabi_dbg_ctx2 );
[9d944b2]	569
	570	// first task to abort ?
[de94a60]	571	if ( kernel_abort_called ) { // not first task to abort ?
[ea7d2b0]	572	unlock( kernel_abort_lock );
[1c273d0]	573
[9d944b2]	574	sigset_t mask;
	575	sigemptyset( &mask );
[de94a60]	576	sigaddset( &mask, SIGALRM ); // block SIGALRM signals
[8a13c47]	577	sigaddset( &mask, SIGUSR1 ); // block SIGALRM signals
	578	sigsuspend( &mask ); // block the processor to prevent further damage during abort
	579	_exit( EXIT_FAILURE ); // if processor unblocks before it is killed, terminate it
[de94a60]	580	}
	581	else {
	582	kernel_abort_called = true;
	583	unlock( kernel_abort_lock );
[9d944b2]	584	}
	585
[14a61b5]	586	return kernelTLS.this_thread;
[9d944b2]	587	}
	588
	589	void kernel_abort_msg( void * kernel_data, char * abort_text, int abort_text_size ) {
[b81fd95]	590	$thread * thrd = ( $thread * ) kernel_data;
[9d944b2]	591
[de94a60]	592	if(thrd) {
	593	int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
[1c40091]	594	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[de94a60]	595
[212c2187]	596	if ( &thrd->self_cor != thrd->curr_cor ) {
	597	len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
[1c40091]	598	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[de94a60]	599	}
	600	else {
[1c40091]	601	__cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
[de94a60]	602	}
[1c273d0]	603	}
[9d944b2]	604	else {
[de94a60]	605	int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
[1c40091]	606	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[9d944b2]	607	}
	608	}
	609
[2b8bc41]	610	int kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
[14a61b5]	611	return get_coroutine(kernelTLS.this_thread) == get_coroutine(mainThread) ? 4 : 2;
[2b8bc41]	612	}
	613
[de94a60]	614	static __spinlock_t kernel_debug_lock;
	615
[9d944b2]	616	extern "C" {
[1c40091]	617	void __cfaabi_bits_acquire() {
[36982fc]	618	lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
[9d944b2]	619	}
	620
[1c40091]	621	void __cfaabi_bits_release() {
[ea7d2b0]	622	unlock( kernel_debug_lock );
[9d944b2]	623	}
[8118303]	624	}
	625
[fa21ac9]	626	//=============================================================================================
	627	// Kernel Utilities
	628	//=============================================================================================
[bd98b58]	629	//-----------------------------------------------------------------------------
	630	// Locks
[242a902]	631	void ?{}( semaphore & this, int count = 1 ) {
	632	(this.lock){};
	633	this.count = count;
	634	(this.waiting){};
[db6f06a]	635	}
[242a902]	636	void ^?{}(semaphore & this) {}
[db6f06a]	637
[71c8b7e]	638	bool P(semaphore & this) with( this ){
[65deb18]	639	lock( lock __cfaabi_dbg_ctx2 );
	640	count -= 1;
	641	if ( count < 0 ) {
[bdeba0b]	642	// queue current task
[14a61b5]	643	append( waiting, kernelTLS.this_thread );
[bdeba0b]	644
	645	// atomically release spin lock and block
[3381ed7]	646	unlock( lock );
[ae66348]	647	park( __cfaabi_dbg_ctx );
[71c8b7e]	648	return true;
[8def349]	649	}
[4e6fb8e]	650	else {
[65deb18]	651	unlock( lock );
[71c8b7e]	652	return false;
[4e6fb8e]	653	}
[bd98b58]	654	}
	655
[f0ce5f4]	656	bool V(semaphore & this) with( this ) {
[ac2b598]	657	$thread * thrd = 0p;
[65deb18]	658	lock( lock __cfaabi_dbg_ctx2 );
	659	count += 1;
	660	if ( count <= 0 ) {
[bdeba0b]	661	// remove task at head of waiting list
[65deb18]	662	thrd = pop_head( waiting );
[bd98b58]	663	}
[bdeba0b]	664
[65deb18]	665	unlock( lock );
[bdeba0b]	666
	667	// make new owner
[ae66348]	668	unpark( thrd __cfaabi_dbg_ctx2 );
[f0ce5f4]	669
[d384787]	670	return thrd != 0p;
	671	}
	672
	673	bool V(semaphore & this, unsigned diff) with( this ) {
	674	$thread * thrd = 0p;
	675	lock( lock __cfaabi_dbg_ctx2 );
	676	int release = max(-count, (int)diff);
	677	count += diff;
	678	for(release) {
	679	unpark( pop_head( waiting ) __cfaabi_dbg_ctx2 );
	680	}
	681
	682	unlock( lock );
	683
[f0ce5f4]	684	return thrd != 0p;
[bd98b58]	685	}
	686
[de94a60]	687	//-----------------------------------------------------------------------------
	688	// Debug
	689	__cfaabi_dbg_debug_do(
[1997b4e]	690	extern "C" {
[ae66348]	691	void __cfaabi_dbg_record_lock(__spinlock_t & this, const char prev_name[]) {
[1997b4e]	692	this.prev_name = prev_name;
	693	this.prev_thrd = kernelTLS.this_thread;
	694	}
[ae66348]	695
	696	void __cfaabi_dbg_record_thrd($thread & this, bool park, const char prev_name[]) {
	697	if(park) {
[f0ce5f4]	698	this.park_caller = prev_name;
	699	this.park_stale = false;
[ae66348]	700	}
	701	else {
[f0ce5f4]	702	this.unpark_caller = prev_name;
	703	this.unpark_stale = false;
[ae66348]	704	}
	705	}
[9181f1d]	706	}
[f7d6bb0]	707	)
[2026bb6]	708
	709	//-----------------------------------------------------------------------------
	710	// Debug
[8c50aed]	711	bool threading_enabled(void) __attribute__((const)) {
[2026bb6]	712	return true;
	713	}
[c34ebf2]	714
	715	//-----------------------------------------------------------------------------
	716	// Statistics
	717	#if !defined(__CFA_NO_STATISTICS__)
	718	void print_halts( processor & this ) {
	719	this.print_halts = true;
	720	}
	721	#endif
[8118303]	722	// Local Variables: //
	723	// mode: c //
	724	// tab-width: 4 //
	725	// End: //

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