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kernel.cfa@ a9172b5

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ADT arm-eh ast-experimental enum forall-pointer-decay jacob/cs343-translation new-ast-unique-expr pthread-emulation qualifiedEnum stuck-waitfor-destruct

Last change on this file since a9172b5 was a9172b5, checked in by Thierry Delisle <tdelisle@…>, 5 years ago
Removed push stats in alternate main
Property mode set to `100644`
File size: 29.4 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
[0190480]	12	// Last Modified On : Mon Aug 31 07:08:20 2020
	13	// Update Count : 71
[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>
[dddb3dd0]	24	extern "C" {
	25	#include <sys/eventfd.h>
	26	}
[8118303]	27
	28	//CFA Includes
[73abe95]	29	#include "kernel_private.hfa"
	30	#include "preemption.hfa"
[8118303]	31
	32	//Private includes
	33	#define __CFA_INVOKE_PRIVATE__
	34	#include "invoke.h"
	35
[89eff25]	36	#if !defined(__CFA_NO_STATISTICS__)
	37	#define __STATS( ...) __VA_ARGS__
	38	#else
	39	#define __STATS( ...)
	40	#endif
[4069faad]	41
[deca0f5]	42	//-----------------------------------------------------------------------------
	43	// Some assembly required
[1805b1b]	44	#if defined( __i386 )
[deca0f5]	45	// mxcr : SSE Status and Control bits (control bits are preserved across function calls)
	46	// fcw : X87 FPU control word (preserved across function calls)
	47	#define __x87_store \
	48	uint32_t __mxcr; \
	49	uint16_t __fcw; \
	50	__asm__ volatile ( \
	51	"stmxcsr %0\n" \
	52	"fnstcw %1\n" \
	53	: "=m" (__mxcr),\
	54	"=m" (__fcw) \
	55	)
	56
	57	#define __x87_load \
	58	__asm__ volatile ( \
	59	"fldcw %1\n" \
	60	"ldmxcsr %0\n" \
	61	::"m" (__mxcr),\
	62	"m" (__fcw) \
	63	)
	64
	65	#elif defined( __x86_64 )
	66	#define __x87_store \
	67	uint32_t __mxcr; \
	68	uint16_t __fcw; \
	69	__asm__ volatile ( \
	70	"stmxcsr %0\n" \
	71	"fnstcw %1\n" \
	72	: "=m" (__mxcr),\
	73	"=m" (__fcw) \
	74	)
	75
	76	#define __x87_load \
	77	__asm__ volatile ( \
	78	"fldcw %1\n" \
	79	"ldmxcsr %0\n" \
	80	:: "m" (__mxcr),\
	81	"m" (__fcw) \
	82	)
	83
[0190480]	84	#elif defined( __arm__ )
	85	#define __x87_store
	86	#define __x87_load
	87
	88	#elif defined( __aarch64__ )
[74f5c83]	89	#define __x87_store \
	90	uint32_t __fpcntl[2]; \
	91	__asm__ volatile ( \
	92	"mrs x9, FPCR\n" \
	93	"mrs x10, FPSR\n" \
	94	"stp x9, x10, %0\n" \
	95	: "=m" (__fpcntl) : : "x9", "x10" \
	96	)
	97
	98	#define __x87_load \
	99	__asm__ volatile ( \
	100	"ldp x9, x10, %0\n" \
	101	"msr FPSR, x10\n" \
	102	"msr FPCR, x9\n" \
	103	: "=m" (__fpcntl) : : "x9", "x10" \
	104	)
	105
[deca0f5]	106	#else
[0190480]	107	#error unsupported hardware architecture
[deca0f5]	108	#endif
	109
[e660761]	110	extern $thread * mainThread;
	111	extern processor * mainProcessor;
[2ac095d]	112
[92e7631]	113	//-----------------------------------------------------------------------------
	114	// Kernel Scheduling logic
	115	static $thread * __next_thread(cluster * this);
[1eb239e4]	116	static $thread * __next_thread_slow(cluster * this);
[c6c7e6c]	117	static inline bool __must_unpark( $thread * thrd ) __attribute((nonnull(1)));
[92e7631]	118	static void __run_thread(processor * this, $thread * dst);
[e873838]	119	static void __wake_one(cluster * cltr);
[1eb239e4]	120
[6a9b12b]	121	static void mark_idle (__cluster_proc_list & idles, processor & proc);
	122	static void mark_awake(__cluster_proc_list & idles, processor & proc);
	123	static [unsigned idle, unsigned total, * processor] query_idles( & __cluster_proc_list idles );
[1eb239e4]	124
[dddb3dd0]	125	extern void __cfa_io_start( processor * );
[c1c95b1]	126	extern bool __cfa_io_drain( processor * );
[dddb3dd0]	127	extern void __cfa_io_flush( processor * );
	128	extern void __cfa_io_stop ( processor * );
[c1c95b1]	129	static inline bool __maybe_io_drain( processor * );
[dddb3dd0]	130
	131	extern void __disable_interrupts_hard();
	132	extern void __enable_interrupts_hard();
[c84e80a]	133
[a3821fa]	134	static inline void __disable_interrupts_checked() {
	135	/* paranoid */ verify( __preemption_enabled() );
	136	disable_interrupts();
	137	/* paranoid */ verify( ! __preemption_enabled() );
	138	}
	139
	140	static inline void __enable_interrupts_checked( bool poll = true ) {
	141	/* paranoid */ verify( ! __preemption_enabled() );
	142	enable_interrupts( poll );
	143	/* paranoid */ verify( __preemption_enabled() );
	144	}
	145
[75f3522]	146	//=============================================================================================
	147	// Kernel Scheduling logic
	148	//=============================================================================================
[8fcbb4c]	149	//Main of the processor contexts
[83a071f9]	150	void main(processorCtx_t & runner) {
[21184e3]	151	// Because of a bug, we couldn't initialized the seed on construction
	152	// Do it here
[8fc652e0]	153	__cfaabi_tls.rand_seed ^= rdtscl();
	154	__cfaabi_tls.ready_rng.fwd_seed = 25214903917_l64u * (rdtscl() ^ (uintptr_t)&runner);
[f2384c9a]	155	__tls_rand_advance_bck();
[21184e3]	156
[83a071f9]	157	processor * this = runner.proc;
[094476d]	158	verify(this);
[c81ebf9]	159
[dddb3dd0]	160	__cfa_io_start( this );
	161
[4069faad]	162	__cfadbg_print_safe(runtime_core, "Kernel : core %p starting\n", this);
[28d73c1]	163	#if !defined(__CFA_NO_STATISTICS__)
	164	if( this->print_halts ) {
[c993b15]	165	__cfaabi_bits_print_safe( STDOUT_FILENO, "Processor : %d - %s (%p)\n", this->unique_id, this->name, (void*)this);
[28d73c1]	166	}
	167	#endif
[b798713]	168
[75f3522]	169	{
[c81ebf9]	170	// Setup preemption data
	171	preemption_scope scope = { this };
	172
[a5e7233]	173	// if we need to run some special setup, now is the time to do it.
	174	if(this->init.thrd) {
	175	this->init.thrd->curr_cluster = this->cltr;
	176	__run_thread(this, this->init.thrd);
	177	}
[325e6ea]	178
[4069faad]	179	__cfadbg_print_safe(runtime_core, "Kernel : core %p started\n", this);
[8118303]	180
[ac2b598]	181	$thread * readyThread = 0p;
[1eb239e4]	182	MAIN_LOOP:
	183	for() {
[34b2796]	184	#if 1
[dddb3dd0]	185	// Check if there is pending io
	186	__maybe_io_drain( this );
	187
[92e7631]	188	// Try to get the next thread
[8c50aed]	189	readyThread = __next_thread( this->cltr );
[75f3522]	190
[1eb239e4]	191	if( !readyThread ) {
[dddb3dd0]	192	__cfa_io_flush( this );
[1eb239e4]	193	readyThread = __next_thread_slow( this->cltr );
	194	}
[4e6fb8e]	195
[1eb239e4]	196	HALT:
	197	if( !readyThread ) {
	198	// Don't block if we are done
	199	if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
[c81ebf9]	200
[1eb239e4]	201	#if !defined(__CFA_NO_STATISTICS__)
	202	__tls_stats()->ready.sleep.halts++;
	203	#endif
[398e8e9]	204
[1eb239e4]	205	// Push self to idle stack
[6a9b12b]	206	mark_idle(this->cltr->procs, * this);
[398e8e9]	207
[1eb239e4]	208	// Confirm the ready-queue is empty
	209	readyThread = __next_thread_slow( this->cltr );
	210	if( readyThread ) {
	211	// A thread was found, cancel the halt
[6a9b12b]	212	mark_awake(this->cltr->procs, * this);
[1eb239e4]	213
	214	#if !defined(__CFA_NO_STATISTICS__)
	215	__tls_stats()->ready.sleep.cancels++;
	216	#endif
	217
	218	// continue the mai loop
	219	break HALT;
	220	}
	221
	222	#if !defined(__CFA_NO_STATISTICS__)
	223	if(this->print_halts) {
[c993b15]	224	__cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 0\n", this->unique_id, rdtscl());
[1eb239e4]	225	}
	226	#endif
	227
[dddb3dd0]	228	__cfadbg_print_safe(runtime_core, "Kernel : core %p waiting on eventfd %d\n", this, this->idle);
	229
	230	__disable_interrupts_hard();
	231	eventfd_t val;
	232	eventfd_read( this->idle, &val );
	233	__enable_interrupts_hard();
[1eb239e4]	234
	235	#if !defined(__CFA_NO_STATISTICS__)
	236	if(this->print_halts) {
[c993b15]	237	__cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 1\n", this->unique_id, rdtscl());
[1eb239e4]	238	}
	239	#endif
	240
	241	// We were woken up, remove self from idle
[6a9b12b]	242	mark_awake(this->cltr->procs, * this);
[1eb239e4]	243
	244	// DON'T just proceed, start looking again
	245	continue MAIN_LOOP;
[64a7146]	246	}
[1eb239e4]	247
	248	/* paranoid */ verify( readyThread );
	249
[dddb3dd0]	250	// Reset io dirty bit
	251	this->io.dirty = false;
	252
[1eb239e4]	253	// We found a thread run it
	254	__run_thread(this, readyThread);
	255
	256	// Are we done?
	257	if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
[325e6ea]	258
[dddb3dd0]	259	if(this->io.pending && !this->io.dirty) {
	260	__cfa_io_flush( this );
	261	}
[89eff25]	262
[34b2796]	263	#else
	264
	265	SEARCH: {
	266	/* paranoid */ verify( ! __preemption_enabled() );
	267
	268	// First, lock the scheduler since we are searching for a thread
	269	ready_schedule_lock();
	270
	271	// Try to get the next thread
	272	readyThread = pop_fast( this->cltr );
	273	if(readyThread) { ready_schedule_unlock(); break SEARCH; }
	274
	275	// If we can't find a thread, might as well flush any outstanding I/O
	276	if(this->io.pending) { __cfa_io_flush( this ); }
	277
	278	// Spin a little on I/O, just in case
	279	for(25) {
	280	__maybe_io_drain( this );
	281	readyThread = pop_fast( this->cltr );
	282	if(readyThread) { ready_schedule_unlock(); break SEARCH; }
	283	}
	284
	285	// no luck, try stealing a few times
	286	for(25) {
	287	if( __maybe_io_drain( this ) ) {
	288	readyThread = pop_fast( this->cltr );
	289	} else {
	290	readyThread = pop_slow( this->cltr );
	291	}
	292	if(readyThread) { ready_schedule_unlock(); break SEARCH; }
	293	}
	294
	295	// still no luck, search for a thread
	296	readyThread = pop_search( this->cltr );
	297	if(readyThread) { ready_schedule_unlock(); break SEARCH; }
	298
	299	// Don't block if we are done
	300	if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
	301
	302	__STATS( __tls_stats()->ready.sleep.halts++; )
	303
	304	// Push self to idle stack
	305	ready_schedule_unlock();
	306	mark_idle(this->cltr->procs, * this);
	307	ready_schedule_lock();
	308
	309	// Confirm the ready-queue is empty
	310	__maybe_io_drain( this );
	311	readyThread = pop_search( this->cltr );
	312	ready_schedule_unlock();
	313
	314	if( readyThread ) {
	315	// A thread was found, cancel the halt
	316	mark_awake(this->cltr->procs, * this);
	317
	318	__STATS( __tls_stats()->ready.sleep.cancels++; )
	319
	320	// continue the main loop
	321	break SEARCH;
	322	}
	323
[fb4ccdf]	324	__STATS( if(this->print_halts) __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 0\n", this->unique_id, rdtscl()); )
[34b2796]	325	__cfadbg_print_safe(runtime_core, "Kernel : core %p waiting on eventfd %d\n", this, this->idle);
	326
	327	// __disable_interrupts_hard();
	328	eventfd_t val;
	329	eventfd_read( this->idle, &val );
	330	// __enable_interrupts_hard();
	331
[fb4ccdf]	332	__STATS( if(this->print_halts) __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 1\n", this->unique_id, rdtscl()); )
[34b2796]	333
	334	// We were woken up, remove self from idle
	335	mark_awake(this->cltr->procs, * this);
	336
	337	// DON'T just proceed, start looking again
	338	continue MAIN_LOOP;
	339	}
	340
	341	RUN_THREAD:
	342	/* paranoid */ verify( ! __preemption_enabled() );
	343	/* paranoid */ verify( readyThread );
	344
	345	// Reset io dirty bit
	346	this->io.dirty = false;
	347
	348	// We found a thread run it
	349	__run_thread(this, readyThread);
	350
	351	// Are we done?
	352	if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
	353
	354	if(this->io.pending && !this->io.dirty) {
	355	__cfa_io_flush( this );
	356	}
	357
	358	ready_schedule_lock();
	359	__maybe_io_drain( this );
	360	ready_schedule_unlock();
	361	#endif
[c81ebf9]	362	}
	363
[4069faad]	364	__cfadbg_print_safe(runtime_core, "Kernel : core %p stopping\n", this);
[c84e80a]	365	}
[8118303]	366
[dddb3dd0]	367	__cfa_io_stop( this );
	368
[454f478]	369	post( this->terminated );
[bdeba0b]	370
[28d73c1]	371	if(this == mainProcessor) {
[6a490b2]	372	// HACK : the coroutine context switch expects this_thread to be set
	373	// and it make sense for it to be set in all other cases except here
	374	// fake it
[8fc652e0]	375	__cfaabi_tls.this_thread = mainThread;
[6a490b2]	376	}
[7768b8d]	377
[4069faad]	378	__cfadbg_print_safe(runtime_core, "Kernel : core %p terminated\n", this);
[c84e80a]	379	}
	380
[5c1a531]	381	static int * __volatile_errno() __attribute__((noinline));
	382	static int * __volatile_errno() { asm(""); return &errno; }
	383
[14a61b5]	384	// KERNEL ONLY
[1c273d0]	385	// runThread runs a thread by context switching
	386	// from the processor coroutine to the target thread
[ac2b598]	387	static void __run_thread(processor * this, $thread * thrd_dst) {
[8fc652e0]	388	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	389	/* paranoid */ verifyf( thrd_dst->state == Ready \|\| thrd_dst->preempted != __NO_PREEMPTION, "state : %d, preempted %d\n", thrd_dst->state, thrd_dst->preempted);
	390	/* paranoid */ verifyf( thrd_dst->link.next == 0p, "Expected null got %p", thrd_dst->link.next );
	391	__builtin_prefetch( thrd_dst->context.SP );
	392
[dddb3dd0]	393	__cfadbg_print_safe(runtime_core, "Kernel : core %p running thread %p (%s)\n", this, thrd_dst, thrd_dst->self_cor.name);
	394
[ac2b598]	395	$coroutine * proc_cor = get_coroutine(this->runner);
[8fcbb4c]	396
[9f575ea]	397	// set state of processor coroutine to inactive
	398	verify(proc_cor->state == Active);
[ae7be7a]	399	proc_cor->state = Blocked;
[e8e457e]	400
[9f575ea]	401	// Actually run the thread
[3381ed7]	402	RUNNING: while(true) {
[ff79d5e]	403	thrd_dst->preempted = __NO_PREEMPTION;
	404	thrd_dst->state = Active;
[e8e457e]	405
[58d64a4]	406	// Update global state
[8fc652e0]	407	kernelTLS().this_thread = thrd_dst;
[75f3522]	408
[8fc652e0]	409	/* paranoid */ verify( ! __preemption_enabled() );
	410	/* paranoid */ verify( kernelTLS().this_thread == thrd_dst );
[9d6e1b8a]	411	/* paranoid */ verify( thrd_dst->curr_cluster == this->cltr );
[b4b63e8]	412	/* paranoid */ verify( thrd_dst->context.SP );
[5afb49a]	413	/* paranoid */ verify( thrd_dst->state != Halted );
[210b8b3]	414	/* 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
	415	/* 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
[ac12f1f]	416	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_dst->canary );
[b4b63e8]	417
[3381ed7]	418
[58d64a4]	419
[9f575ea]	420	// set context switch to the thread that the processor is executing
[c7a900a]	421	__cfactx_switch( &proc_cor->context, &thrd_dst->context );
	422	// when __cfactx_switch returns we are back in the processor coroutine
[9f575ea]	423
[ac12f1f]	424	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_dst->canary );
[210b8b3]	425	/* 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 );
	426	/* paranoid */ verifyf( ((uintptr_t)thrd_dst->context.SP) < ((uintptr_t)__get_stack(thrd_dst->curr_cor)->base ), "ERROR : Destination $thread %p has been corrupted.\n StackPointer too small.\n", thrd_dst );
[b4b63e8]	427	/* paranoid */ verify( thrd_dst->context.SP );
[9d6e1b8a]	428	/* paranoid */ verify( thrd_dst->curr_cluster == this->cltr );
[8fc652e0]	429	/* paranoid */ verify( kernelTLS().this_thread == thrd_dst );
	430	/* paranoid */ verify( ! __preemption_enabled() );
[75f3522]	431
[58d64a4]	432	// Reset global state
[8fc652e0]	433	kernelTLS().this_thread = 0p;
[3381ed7]	434
	435	// We just finished running a thread, there are a few things that could have happened.
	436	// 1 - Regular case : the thread has blocked and now one has scheduled it yet.
	437	// 2 - Racy case : the thread has blocked but someone has already tried to schedule it.
	438	// 4 - Preempted
	439	// In case 1, we may have won a race so we can't write to the state again.
	440	// In case 2, we lost the race so we now own the thread.
	441
	442	if(unlikely(thrd_dst->preempted != __NO_PREEMPTION)) {
	443	// The thread was preempted, reschedule it and reset the flag
[254ad1b]	444	schedule_thread$( thrd_dst );
[3381ed7]	445	break RUNNING;
	446	}
[75f3522]	447
[3ea8ad1]	448	if(unlikely(thrd_dst->state == Halting)) {
[ff79d5e]	449	// The thread has halted, it should never be scheduled/run again
[5afb49a]	450	// finish the thread
	451	__thread_finish( thrd_dst );
[ff79d5e]	452	break RUNNING;
	453	}
	454
	455	/* paranoid */ verify( thrd_dst->state == Active );
	456	thrd_dst->state = Blocked;
	457
[3381ed7]	458	// set state of processor coroutine to active and the thread to inactive
[ff79d5e]	459	int old_ticket = __atomic_fetch_sub(&thrd_dst->ticket, 1, __ATOMIC_SEQ_CST);
	460	switch(old_ticket) {
[6a77224]	461	case TICKET_RUNNING:
[3381ed7]	462	// This is case 1, the regular case, nothing more is needed
	463	break RUNNING;
[6a77224]	464	case TICKET_UNBLOCK:
[ec43cf9]	465	#if !defined(__CFA_NO_STATISTICS__)
	466	__tls_stats()->ready.threads.threads++;
[73f4d08]	467	__push_stat( __tls_stats(), __tls_stats()->ready.threads.threads, false, "Processor", this );
[ec43cf9]	468	#endif
[3381ed7]	469	// This is case 2, the racy case, someone tried to run this thread before it finished blocking
	470	// In this case, just run it again.
	471	continue RUNNING;
	472	default:
	473	// This makes no sense, something is wrong abort
[ff79d5e]	474	abort();
[3381ed7]	475	}
[9f575ea]	476	}
[e8e457e]	477
[9f575ea]	478	// Just before returning to the processor, set the processor coroutine to active
[e8e457e]	479	proc_cor->state = Active;
[1eb239e4]	480
[dddb3dd0]	481	__cfadbg_print_safe(runtime_core, "Kernel : core %p finished running thread %p\n", this, thrd_dst);
	482
[ec43cf9]	483	#if !defined(__CFA_NO_STATISTICS__)
	484	__tls_stats()->ready.threads.threads--;
[73f4d08]	485	__push_stat( __tls_stats(), __tls_stats()->ready.threads.threads, false, "Processor", this );
[ec43cf9]	486	#endif
	487
[8fc652e0]	488	/* paranoid */ verify( ! __preemption_enabled() );
[82c948c]	489	}
	490
[14a61b5]	491	// KERNEL_ONLY
[b0c7419]	492	void returnToKernel() {
[8fc652e0]	493	/* paranoid */ verify( ! __preemption_enabled() );
	494	$coroutine * proc_cor = get_coroutine(kernelTLS().this_processor->runner);
	495	$thread * thrd_src = kernelTLS().this_thread;
[e8e457e]	496
[89eff25]	497	__STATS( thrd_src->last_proc = kernelTLS().this_processor; )
[29cb302]	498
[9f575ea]	499	// Run the thread on this processor
	500	{
	501	int local_errno = *__volatile_errno();
	502	#if defined( __i386 ) \|\| defined( __x86_64 )
	503	__x87_store;
	504	#endif
[b4b63e8]	505	/* paranoid */ verify( proc_cor->context.SP );
[ac12f1f]	506	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_src->canary );
[c7a900a]	507	__cfactx_switch( &thrd_src->context, &proc_cor->context );
[ac12f1f]	508	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_src->canary );
[9f575ea]	509	#if defined( __i386 ) \|\| defined( __x86_64 )
	510	__x87_load;
	511	#endif
	512	*__volatile_errno() = local_errno;
[8fcbb4c]	513	}
[deca0f5]	514
[29cb302]	515	#if !defined(__CFA_NO_STATISTICS__)
[89eff25]	516	/* paranoid */ verify( thrd_src->last_proc != 0p );
	517	if(thrd_src->last_proc != kernelTLS().this_processor) {
[29cb302]	518	__tls_stats()->ready.threads.migration++;
	519	}
	520	#endif
	521
[8fc652e0]	522	/* paranoid */ verify( ! __preemption_enabled() );
[210b8b3]	523	/* 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 );
	524	/* 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]	525	}
	526
[8def349]	527	//-----------------------------------------------------------------------------
	528	// Scheduler routines
[14a61b5]	529	// KERNEL ONLY
[e9c0b4c]	530	static void __schedule_thread( $thread * thrd ) {
[8fc652e0]	531	/* paranoid */ verify( ! __preemption_enabled() );
[254ad1b]	532	/* paranoid */ verify( ready_schedule_islocked());
[6a490b2]	533	/* paranoid */ verify( thrd );
	534	/* paranoid */ verify( thrd->state != Halted );
[9d6e1b8a]	535	/* paranoid */ verify( thrd->curr_cluster );
[3381ed7]	536	/* paranoid */ #if defined( __CFA_WITH_VERIFY__ )
[504a7dc]	537	/* paranoid */ if( thrd->state == Blocked \|\| thrd->state == Start ) assertf( thrd->preempted == __NO_PREEMPTION,
	538	"Error inactive thread marked as preempted, state %d, preemption %d\n", thrd->state, thrd->preempted );
[ff79d5e]	539	/* paranoid */ if( thrd->preempted != __NO_PREEMPTION ) assertf(thrd->state == Active,
[504a7dc]	540	"Error preempted thread marked as not currently running, state %d, preemption %d\n", thrd->state, thrd->preempted );
[3381ed7]	541	/* paranoid */ #endif
[6a490b2]	542	/* paranoid */ verifyf( thrd->link.next == 0p, "Expected null got %p", thrd->link.next );
[ac12f1f]	543	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd->canary );
[b4b63e8]	544
[9f575ea]	545
[ae7be7a]	546	if (thrd->preempted == __NO_PREEMPTION) thrd->state = Ready;
[6b4cdd3]	547
[ec43cf9]	548	// Dereference the thread now because once we push it, there is not guaranteed it's still valid.
	549	struct cluster * cl = thrd->curr_cluster;
[89eff25]	550	__STATS(bool outside = thrd->last_proc && thrd->last_proc != kernelTLS().this_processor; )
[32a8b61]	551
[254ad1b]	552	// push the thread to the cluster ready-queue
	553	push( cl, thrd );
[32a8b61]	554
[254ad1b]	555	// variable thrd is no longer safe to use
[734908c]	556	thrd = 0xdeaddeaddeaddeadp;
[32a8b61]	557
[254ad1b]	558	// wake the cluster using the save variable.
	559	__wake_one( cl );
[1c273d0]	560
[ec43cf9]	561	#if !defined(__CFA_NO_STATISTICS__)
	562	if( kernelTLS().this_stats ) {
	563	__tls_stats()->ready.threads.threads++;
[89eff25]	564	if(outside) {
	565	__tls_stats()->ready.threads.extunpark++;
	566	}
[73f4d08]	567	__push_stat( __tls_stats(), __tls_stats()->ready.threads.threads, false, "Processor", kernelTLS().this_processor );
[ec43cf9]	568	}
	569	else {
	570	__atomic_fetch_add(&cl->stats->ready.threads.threads, 1, __ATOMIC_RELAXED);
[89eff25]	571	__atomic_fetch_add(&cl->stats->ready.threads.extunpark, 1, __ATOMIC_RELAXED);
[73f4d08]	572	__push_stat( cl->stats, cl->stats->ready.threads.threads, true, "Cluster", cl );
[ec43cf9]	573	}
	574	#endif
	575
[254ad1b]	576	/* paranoid */ verify( ready_schedule_islocked());
[8fc652e0]	577	/* paranoid */ verify( ! __preemption_enabled() );
[db6f06a]	578	}
	579
[254ad1b]	580	void schedule_thread$( $thread * thrd ) {
	581	ready_schedule_lock();
	582	__schedule_thread( thrd );
	583	ready_schedule_unlock();
	584	}
	585
[14a61b5]	586	// KERNEL ONLY
[1eb239e4]	587	static inline $thread * __next_thread(cluster * this) with( *this ) {
[8fc652e0]	588	/* paranoid */ verify( ! __preemption_enabled() );
[7768b8d]	589
[e873838]	590	ready_schedule_lock();
[431cd4f]	591	$thread * thrd = pop_fast( this );
[e873838]	592	ready_schedule_unlock();
[7768b8d]	593
[8fc652e0]	594	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	595	return thrd;
[eb2e723]	596	}
	597
[64a7146]	598	// KERNEL ONLY
[1eb239e4]	599	static inline $thread * __next_thread_slow(cluster * this) with( *this ) {
[8fc652e0]	600	/* paranoid */ verify( ! __preemption_enabled() );
[64a7146]	601
[e873838]	602	ready_schedule_lock();
[fc59df78]	603	$thread * thrd;
	604	for(25) {
	605	thrd = pop_slow( this );
	606	if(thrd) goto RET;
	607	}
	608	thrd = pop_search( this );
	609
	610	RET:
[e873838]	611	ready_schedule_unlock();
[64a7146]	612
[8fc652e0]	613	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	614	return thrd;
[64a7146]	615	}
	616
[c6c7e6c]	617	static inline bool __must_unpark( $thread * thrd ) {
[ff79d5e]	618	int old_ticket = __atomic_fetch_add(&thrd->ticket, 1, __ATOMIC_SEQ_CST);
	619	switch(old_ticket) {
[6a77224]	620	case TICKET_RUNNING:
[3381ed7]	621	// Wake won the race, the thread will reschedule/rerun itself
[c6c7e6c]	622	return false;
[6a77224]	623	case TICKET_BLOCKED:
[3381ed7]	624	/* paranoid */ verify( ! thrd->preempted != __NO_PREEMPTION );
[ff79d5e]	625	/* paranoid */ verify( thrd->state == Blocked );
[c6c7e6c]	626	return true;
[3381ed7]	627	default:
	628	// This makes no sense, something is wrong abort
[7ee8153]	629	abort("Thread %p (%s) has mismatch park/unpark\n", thrd, thrd->self_cor.name);
[de6319f]	630	}
[eb2e723]	631	}
	632
[e9c0b4c]	633	void __kernel_unpark( $thread * thrd ) {
	634	/* paranoid */ verify( ! __preemption_enabled() );
	635	/* paranoid */ verify( ready_schedule_islocked());
	636
	637	if( !thrd ) return;
	638
	639	if(__must_unpark(thrd)) {
	640	// Wake lost the race,
	641	__schedule_thread( thrd );
	642	}
	643
	644	/* paranoid */ verify( ready_schedule_islocked());
	645	/* paranoid */ verify( ! __preemption_enabled() );
	646	}
	647
[c6c7e6c]	648	void unpark( $thread * thrd ) {
	649	if( !thrd ) return;
[0b33412]	650
[c6c7e6c]	651	if(__must_unpark(thrd)) {
	652	disable_interrupts();
[a3821fa]	653	// Wake lost the race,
[254ad1b]	654	schedule_thread$( thrd );
[a3821fa]	655	enable_interrupts(false);
[de6319f]	656	}
[eb2e723]	657	}
[0b33412]	658
[e235429]	659	void park( void ) {
[a3821fa]	660	__disable_interrupts_checked();
	661	/* paranoid */ verify( kernelTLS().this_thread->preempted == __NO_PREEMPTION );
	662	returnToKernel();
	663	__enable_interrupts_checked();
[0c78741]	664
	665	}
[09800e9]	666
[5afb49a]	667	extern "C" {
	668	// Leave the thread monitor
	669	// last routine called by a thread.
	670	// Should never return
	671	void __cfactx_thrd_leave() {
[8fc652e0]	672	$thread * thrd = active_thread();
[5afb49a]	673	$monitor * this = &thrd->self_mon;
	674
	675	// Lock the monitor now
	676	lock( this->lock __cfaabi_dbg_ctx2 );
	677
	678	disable_interrupts();
	679
[9d6e1b8a]	680	/* paranoid */ verify( ! __preemption_enabled() );
	681	/* paranoid */ verify( thrd->state == Active );
	682	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd->canary );
	683	/* paranoid */ verify( kernelTLS().this_thread == thrd );
	684	/* paranoid */ verify( thrd->context.SP );
	685	/* 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 );
	686	/* 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 );
	687
[3ea8ad1]	688	thrd->state = Halting;
[58688bf]	689	if( TICKET_RUNNING != thrd->ticket ) { abort( "Thread terminated with pending unpark" ); }
[9d6e1b8a]	690	if( thrd != this->owner ) { abort( "Thread internal monitor has incorrect owner" ); }
	691	if( this->recursion != 1) { abort( "Thread internal monitor has unbalanced recursion" ); }
[5afb49a]	692
	693	// Leave the thread
	694	returnToKernel();
	695
	696	// Control flow should never reach here!
[9d6e1b8a]	697	abort();
[5afb49a]	698	}
[09800e9]	699	}
	700
[14a61b5]	701	// KERNEL ONLY
[3381ed7]	702	bool force_yield( __Preemption_Reason reason ) {
[a3821fa]	703	__disable_interrupts_checked();
	704	$thread * thrd = kernelTLS().this_thread;
	705	/* paranoid */ verify(thrd->state == Active);
	706
	707	// SKULLDUGGERY: It is possible that we are preempting this thread just before
	708	// it was going to park itself. If that is the case and it is already using the
	709	// intrusive fields then we can't use them to preempt the thread
	710	// If that is the case, abandon the preemption.
	711	bool preempted = false;
	712	if(thrd->link.next == 0p) {
	713	preempted = true;
	714	thrd->preempted = reason;
	715	returnToKernel();
	716	}
	717	__enable_interrupts_checked( false );
[3381ed7]	718	return preempted;
[f2b12406]	719	}
	720
[14a61b5]	721	//=============================================================================================
[92e7631]	722	// Kernel Idle Sleep
[14a61b5]	723	//=============================================================================================
[64a7146]	724	// Wake a thread from the front if there are any
[e873838]	725	static void __wake_one(cluster * this) {
[8fc652e0]	726	/* paranoid */ verify( ! __preemption_enabled() );
[e873838]	727	/* paranoid */ verify( ready_schedule_islocked() );
[14a61b5]	728
[64a7146]	729	// Check if there is a sleeping processor
[1eb239e4]	730	processor * p;
	731	unsigned idle;
	732	unsigned total;
[6a9b12b]	733	[idle, total, p] = query_idles(this->procs);
[14a61b5]	734
[64a7146]	735	// If no one is sleeping, we are done
[1eb239e4]	736	if( idle == 0 ) return;
[14a61b5]	737
[64a7146]	738	// We found a processor, wake it up
[dddb3dd0]	739	eventfd_t val;
	740	val = 1;
	741	eventfd_write( p->idle, val );
[14a61b5]	742
[1eb239e4]	743	#if !defined(__CFA_NO_STATISTICS__)
[5cb51502]	744	if( kernelTLS().this_stats ) {
	745	__tls_stats()->ready.sleep.wakes++;
	746	}
	747	else {
	748	__atomic_fetch_add(&this->stats->ready.sleep.wakes, 1, __ATOMIC_RELAXED);
	749	}
[1eb239e4]	750	#endif
	751
[e873838]	752	/* paranoid */ verify( ready_schedule_islocked() );
[8fc652e0]	753	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	754
	755	return;
[64a7146]	756	}
[14a61b5]	757
[64a7146]	758	// Unconditionnaly wake a thread
[1eb239e4]	759	void __wake_proc(processor * this) {
[64a7146]	760	__cfadbg_print_safe(runtime_core, "Kernel : waking Processor %p\n", this);
[14a61b5]	761
[a3821fa]	762	__disable_interrupts_checked();
[8fc652e0]	763	/* paranoid */ verify( ! __preemption_enabled() );
[dddb3dd0]	764	eventfd_t val;
	765	val = 1;
[55d6affb]	766	eventfd_write( this->idle, val );
[a3821fa]	767	__enable_interrupts_checked();
[92e7631]	768	}
	769
[6a9b12b]	770	static void mark_idle(__cluster_proc_list & this, processor & proc) {
[8fc652e0]	771	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	772	lock( this );
	773	this.idle++;
	774	/* paranoid */ verify( this.idle <= this.total );
[fc59b580]	775	remove(proc);
[6a9b12b]	776	insert_first(this.idles, proc);
[1eb239e4]	777	unlock( this );
[8fc652e0]	778	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	779	}
[8e16177]	780
[6a9b12b]	781	static void mark_awake(__cluster_proc_list & this, processor & proc) {
[8fc652e0]	782	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	783	lock( this );
	784	this.idle--;
	785	/* paranoid */ verify( this.idle >= 0 );
	786	remove(proc);
[fc59b580]	787	insert_last(this.actives, proc);
[1eb239e4]	788	unlock( this );
[8fc652e0]	789	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	790	}
[c34ebf2]	791
[6a9b12b]	792	static [unsigned idle, unsigned total, * processor] query_idles( & __cluster_proc_list this ) {
	793	/* paranoid */ verify( ! __preemption_enabled() );
	794	/* paranoid */ verify( ready_schedule_islocked() );
	795
[1eb239e4]	796	for() {
	797	uint64_t l = __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST);
	798	if( 1 == (l % 2) ) { Pause(); continue; }
	799	unsigned idle = this.idle;
	800	unsigned total = this.total;
[6a9b12b]	801	processor * proc = &this.idles`first;
[7fdae38]	802	// Compiler fence is unnecessary, but gcc-8 and older incorrectly reorder code without it
	803	asm volatile("": : :"memory");
[1eb239e4]	804	if(l != __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST)) { Pause(); continue; }
	805	return [idle, total, proc];
	806	}
[6a9b12b]	807
	808	/* paranoid */ verify( ready_schedule_islocked() );
	809	/* paranoid */ verify( ! __preemption_enabled() );
[6b4cdd3]	810	}
	811
[dbe9b08]	812	//=============================================================================================
	813	// Unexpected Terminating logic
	814	//=============================================================================================
[92bfda0]	815	void __kernel_abort_msg( char * abort_text, int abort_text_size ) {
	816	$thread * thrd = __cfaabi_tls.this_thread;
[9d944b2]	817
[de94a60]	818	if(thrd) {
	819	int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
[1c40091]	820	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[de94a60]	821
[212c2187]	822	if ( &thrd->self_cor != thrd->curr_cor ) {
	823	len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
[1c40091]	824	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[de94a60]	825	}
	826	else {
[1c40091]	827	__cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
[de94a60]	828	}
[1c273d0]	829	}
[9d944b2]	830	else {
[de94a60]	831	int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
[1c40091]	832	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[9d944b2]	833	}
	834	}
	835
[92bfda0]	836	int __kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
	837	return get_coroutine(__cfaabi_tls.this_thread) == get_coroutine(mainThread) ? 4 : 2;
[2b8bc41]	838	}
	839
[de94a60]	840	static __spinlock_t kernel_debug_lock;
	841
[9d944b2]	842	extern "C" {
[1c40091]	843	void __cfaabi_bits_acquire() {
[36982fc]	844	lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
[9d944b2]	845	}
	846
[1c40091]	847	void __cfaabi_bits_release() {
[ea7d2b0]	848	unlock( kernel_debug_lock );
[9d944b2]	849	}
[8118303]	850	}
	851
[fa21ac9]	852	//=============================================================================================
	853	// Kernel Utilities
	854	//=============================================================================================
[dddb3dd0]	855	#if defined(CFA_HAVE_LINUX_IO_URING_H)
	856	#include "io/types.hfa"
	857	#endif
	858
[c1c95b1]	859	static inline bool __maybe_io_drain( processor * proc ) {
[e9c0b4c]	860	bool ret = false;
[dddb3dd0]	861	#if defined(CFA_HAVE_LINUX_IO_URING_H)
	862	__cfadbg_print_safe(runtime_core, "Kernel : core %p checking io for ring %d\n", proc, proc->io.ctx->fd);
	863
	864	// Check if we should drain the queue
	865	$io_context * ctx = proc->io.ctx;
	866	unsigned head = *ctx->cq.head;
	867	unsigned tail = *ctx->cq.tail;
[c1c95b1]	868	if(head == tail) return false;
[b7fd2db6]	869	ready_schedule_lock();
[e9c0b4c]	870	ret = __cfa_io_drain( proc );
[b7fd2db6]	871	ready_schedule_unlock();
[dddb3dd0]	872	#endif
[e9c0b4c]	873	return ret;
[dddb3dd0]	874	}
	875
[de94a60]	876	//-----------------------------------------------------------------------------
	877	// Debug
	878	__cfaabi_dbg_debug_do(
[1997b4e]	879	extern "C" {
[ae66348]	880	void __cfaabi_dbg_record_lock(__spinlock_t & this, const char prev_name[]) {
[1997b4e]	881	this.prev_name = prev_name;
[8fc652e0]	882	this.prev_thrd = kernelTLS().this_thread;
[1997b4e]	883	}
[9181f1d]	884	}
[f7d6bb0]	885	)
[2026bb6]	886
	887	//-----------------------------------------------------------------------------
	888	// Debug
[8c50aed]	889	bool threading_enabled(void) __attribute__((const)) {
[2026bb6]	890	return true;
	891	}
[c34ebf2]	892
	893	//-----------------------------------------------------------------------------
	894	// Statistics
	895	#if !defined(__CFA_NO_STATISTICS__)
	896	void print_halts( processor & this ) {
	897	this.print_halts = true;
	898	}
[58688bf]	899
[8464edf]	900	static void crawl_list( cluster * cltr, dlist(processor, processor) & list, unsigned count ) {
	901	/* paranoid */ verify( cltr->stats );
	902
	903	processor * it = &list`first;
	904	for(unsigned i = 0; i < count; i++) {
	905	/* paranoid */ verifyf( it, "Unexpected null iterator, at index %u of %u\n", i, count);
	906	/* paranoid */ verify( it->local_data->this_stats );
	907	__tally_stats( cltr->stats, it->local_data->this_stats );
	908	it = &(*it)`next;
	909	}
	910	}
	911
	912	void crawl_cluster_stats( cluster & this ) {
	913	// Stop the world, otherwise stats could get really messed-up
	914	// this doesn't solve all problems but does solve many
	915	// so it's probably good enough
	916	uint_fast32_t last_size = ready_mutate_lock();
	917
	918	crawl_list(&this, this.procs.actives, this.procs.total - this.procs.idle);
	919	crawl_list(&this, this.procs.idles , this.procs.idle );
	920
	921	// Unlock the RWlock
	922	ready_mutate_unlock( last_size );
	923	}
	924
	925
[58688bf]	926	void print_stats_now( cluster & this, int flags ) {
[8464edf]	927	crawl_cluster_stats( this );
[1b033b8]	928	__print_stats( this.stats, this.print_stats, "Cluster", this.name, (void*)&this );
	929	}
[c34ebf2]	930	#endif
[8118303]	931	// Local Variables: //
	932	// mode: c //
	933	// tab-width: 4 //
	934	// End: //

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