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kernel.cfa@ 2b96031

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

Last change on this file since 2b96031 was c993b15, checked in by Thierry Delisle <tdelisle@…>, 4 years ago
Changed RW lock to avoid hitting the global array on schedule.
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
[89eff25]	173	__STATS( unsigned long long last_tally = rdtscl(); )
[325e6ea]	174
[a5e7233]	175	// if we need to run some special setup, now is the time to do it.
	176	if(this->init.thrd) {
	177	this->init.thrd->curr_cluster = this->cltr;
	178	__run_thread(this, this->init.thrd);
	179	}
[325e6ea]	180
[4069faad]	181	__cfadbg_print_safe(runtime_core, "Kernel : core %p started\n", this);
[8118303]	182
[ac2b598]	183	$thread * readyThread = 0p;
[1eb239e4]	184	MAIN_LOOP:
	185	for() {
[dddb3dd0]	186	// Check if there is pending io
	187	__maybe_io_drain( this );
	188
[92e7631]	189	// Try to get the next thread
[8c50aed]	190	readyThread = __next_thread( this->cltr );
[75f3522]	191
[1eb239e4]	192	if( !readyThread ) {
[dddb3dd0]	193	__cfa_io_flush( this );
[1eb239e4]	194	readyThread = __next_thread_slow( this->cltr );
	195	}
[4e6fb8e]	196
[1eb239e4]	197	HALT:
	198	if( !readyThread ) {
	199	// Don't block if we are done
	200	if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
[c81ebf9]	201
[1eb239e4]	202	#if !defined(__CFA_NO_STATISTICS__)
	203	__tls_stats()->ready.sleep.halts++;
	204	#endif
[398e8e9]	205
[1eb239e4]	206	// Push self to idle stack
[6a9b12b]	207	mark_idle(this->cltr->procs, * this);
[398e8e9]	208
[1eb239e4]	209	// Confirm the ready-queue is empty
	210	readyThread = __next_thread_slow( this->cltr );
	211	if( readyThread ) {
	212	// A thread was found, cancel the halt
[6a9b12b]	213	mark_awake(this->cltr->procs, * this);
[1eb239e4]	214
	215	#if !defined(__CFA_NO_STATISTICS__)
	216	__tls_stats()->ready.sleep.cancels++;
	217	#endif
	218
	219	// continue the mai loop
	220	break HALT;
	221	}
	222
	223	#if !defined(__CFA_NO_STATISTICS__)
	224	if(this->print_halts) {
[c993b15]	225	__cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 0\n", this->unique_id, rdtscl());
[1eb239e4]	226	}
	227	#endif
	228
[dddb3dd0]	229	__cfadbg_print_safe(runtime_core, "Kernel : core %p waiting on eventfd %d\n", this, this->idle);
	230
	231	__disable_interrupts_hard();
	232	eventfd_t val;
	233	eventfd_read( this->idle, &val );
	234	__enable_interrupts_hard();
[1eb239e4]	235
	236	#if !defined(__CFA_NO_STATISTICS__)
	237	if(this->print_halts) {
[c993b15]	238	__cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 1\n", this->unique_id, rdtscl());
[1eb239e4]	239	}
	240	#endif
	241
	242	// We were woken up, remove self from idle
[6a9b12b]	243	mark_awake(this->cltr->procs, * this);
[1eb239e4]	244
	245	// DON'T just proceed, start looking again
	246	continue MAIN_LOOP;
[64a7146]	247	}
[1eb239e4]	248
	249	/* paranoid */ verify( readyThread );
	250
[dddb3dd0]	251	// Reset io dirty bit
	252	this->io.dirty = false;
	253
[1eb239e4]	254	// We found a thread run it
	255	__run_thread(this, readyThread);
	256
	257	// Are we done?
	258	if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
[325e6ea]	259
	260	#if !defined(__CFA_NO_STATISTICS__)
	261	unsigned long long curr = rdtscl();
	262	if(curr > (last_tally + 500000000)) {
	263	__tally_stats(this->cltr->stats, __cfaabi_tls.this_stats);
	264	last_tally = curr;
	265	}
	266	#endif
[dddb3dd0]	267
	268	if(this->io.pending && !this->io.dirty) {
	269	__cfa_io_flush( this );
	270	}
[89eff25]	271
	272	// SEARCH: {
	273	// /* paranoid */ verify( ! __preemption_enabled() );
	274	// /* paranoid */ verify( kernelTLS().this_proc_id );
	275
	276	// // First, lock the scheduler since we are searching for a thread
	277
	278	// // Try to get the next thread
	279	// ready_schedule_lock();
	280	// readyThread = pop_fast( this->cltr );
	281	// ready_schedule_unlock();
	282	// if(readyThread) { break SEARCH; }
	283
	284	// // If we can't find a thread, might as well flush any outstanding I/O
	285	// if(this->io.pending) { __cfa_io_flush( this ); }
	286
	287	// // Spin a little on I/O, just in case
	288	// for(25) {
	289	// __maybe_io_drain( this );
	290	// ready_schedule_lock();
	291	// readyThread = pop_fast( this->cltr );
	292	// ready_schedule_unlock();
	293	// if(readyThread) { break SEARCH; }
	294	// }
	295
	296	// // no luck, try stealing a few times
	297	// for(25) {
	298	// if( __maybe_io_drain( this ) ) {
	299	// ready_schedule_lock();
	300	// readyThread = pop_fast( this->cltr );
	301	// } else {
	302	// ready_schedule_lock();
	303	// readyThread = pop_slow( this->cltr );
	304	// }
	305	// ready_schedule_unlock();
	306	// if(readyThread) { break SEARCH; }
	307	// }
	308
	309	// // still no luck, search for a thread
	310	// ready_schedule_lock();
	311	// readyThread = pop_search( this->cltr );
	312	// ready_schedule_unlock();
	313	// if(readyThread) { break SEARCH; }
	314
	315	// // Don't block if we are done
	316	// if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
	317
	318	// __STATS( __tls_stats()->ready.sleep.halts++; )
	319
	320	// // Push self to idle stack
	321	// mark_idle(this->cltr->procs, * this);
	322
	323	// // Confirm the ready-queue is empty
	324	// __maybe_io_drain( this );
	325	// ready_schedule_lock();
	326	// readyThread = pop_search( this->cltr );
	327	// ready_schedule_unlock();
	328
	329	// if( readyThread ) {
	330	// // A thread was found, cancel the halt
	331	// mark_awake(this->cltr->procs, * this);
	332
	333	// __STATS( __tls_stats()->ready.sleep.cancels++; )
	334
	335	// // continue the main loop
	336	// break SEARCH;
	337	// }
	338
	339	// __STATS( if(this->print_halts) __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 0\n", this->id, rdtscl()); )
	340	// __cfadbg_print_safe(runtime_core, "Kernel : core %p waiting on eventfd %d\n", this, this->idle);
	341
	342	// // __disable_interrupts_hard();
	343	// eventfd_t val;
	344	// eventfd_read( this->idle, &val );
	345	// // __enable_interrupts_hard();
	346
	347	// __STATS( if(this->print_halts) __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 1\n", this->id, rdtscl()); )
	348
	349	// // We were woken up, remove self from idle
	350	// mark_awake(this->cltr->procs, * this);
	351
	352	// // DON'T just proceed, start looking again
	353	// continue MAIN_LOOP;
	354	// }
	355
	356	// RUN_THREAD:
	357	// /* paranoid */ verify( kernelTLS().this_proc_id );
	358	// /* paranoid */ verify( ! __preemption_enabled() );
	359	// /* paranoid */ verify( readyThread );
	360
	361	// // Reset io dirty bit
	362	// this->io.dirty = false;
	363
	364	// // We found a thread run it
	365	// __run_thread(this, readyThread);
	366
	367	// // Are we done?
	368	// if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
	369
	370	// #if !defined(__CFA_NO_STATISTICS__)
	371	// unsigned long long curr = rdtscl();
	372	// if(curr > (last_tally + 500000000)) {
	373	// __tally_stats(this->cltr->stats, __cfaabi_tls.this_stats);
	374	// last_tally = curr;
	375	// }
	376	// #endif
	377
	378	// if(this->io.pending && !this->io.dirty) {
	379	// __cfa_io_flush( this );
	380	// }
	381
	382	// // Check if there is pending io
	383	// __maybe_io_drain( this );
[c81ebf9]	384	}
	385
[4069faad]	386	__cfadbg_print_safe(runtime_core, "Kernel : core %p stopping\n", this);
[c84e80a]	387	}
[8118303]	388
[dddb3dd0]	389	__cfa_io_stop( this );
	390
[454f478]	391	post( this->terminated );
[bdeba0b]	392
[28d73c1]	393	if(this == mainProcessor) {
[6a490b2]	394	// HACK : the coroutine context switch expects this_thread to be set
	395	// and it make sense for it to be set in all other cases except here
	396	// fake it
[8fc652e0]	397	__cfaabi_tls.this_thread = mainThread;
[6a490b2]	398	}
[7768b8d]	399
[4069faad]	400	__cfadbg_print_safe(runtime_core, "Kernel : core %p terminated\n", this);
[c84e80a]	401	}
	402
[5c1a531]	403	static int * __volatile_errno() __attribute__((noinline));
	404	static int * __volatile_errno() { asm(""); return &errno; }
	405
[14a61b5]	406	// KERNEL ONLY
[1c273d0]	407	// runThread runs a thread by context switching
	408	// from the processor coroutine to the target thread
[ac2b598]	409	static void __run_thread(processor * this, $thread * thrd_dst) {
[8fc652e0]	410	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	411	/* paranoid */ verifyf( thrd_dst->state == Ready \|\| thrd_dst->preempted != __NO_PREEMPTION, "state : %d, preempted %d\n", thrd_dst->state, thrd_dst->preempted);
	412	/* paranoid */ verifyf( thrd_dst->link.next == 0p, "Expected null got %p", thrd_dst->link.next );
	413	__builtin_prefetch( thrd_dst->context.SP );
	414
[dddb3dd0]	415	__cfadbg_print_safe(runtime_core, "Kernel : core %p running thread %p (%s)\n", this, thrd_dst, thrd_dst->self_cor.name);
	416
[ac2b598]	417	$coroutine * proc_cor = get_coroutine(this->runner);
[8fcbb4c]	418
[9f575ea]	419	// set state of processor coroutine to inactive
	420	verify(proc_cor->state == Active);
[ae7be7a]	421	proc_cor->state = Blocked;
[e8e457e]	422
[9f575ea]	423	// Actually run the thread
[3381ed7]	424	RUNNING: while(true) {
[ff79d5e]	425	thrd_dst->preempted = __NO_PREEMPTION;
	426	thrd_dst->state = Active;
[e8e457e]	427
[58d64a4]	428	// Update global state
[8fc652e0]	429	kernelTLS().this_thread = thrd_dst;
[75f3522]	430
[8fc652e0]	431	/* paranoid */ verify( ! __preemption_enabled() );
	432	/* paranoid */ verify( kernelTLS().this_thread == thrd_dst );
[9d6e1b8a]	433	/* paranoid */ verify( thrd_dst->curr_cluster == this->cltr );
[b4b63e8]	434	/* paranoid */ verify( thrd_dst->context.SP );
[5afb49a]	435	/* paranoid */ verify( thrd_dst->state != Halted );
[210b8b3]	436	/* 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
	437	/* 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]	438	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_dst->canary );
[b4b63e8]	439
[3381ed7]	440
[58d64a4]	441
[9f575ea]	442	// set context switch to the thread that the processor is executing
[c7a900a]	443	__cfactx_switch( &proc_cor->context, &thrd_dst->context );
	444	// when __cfactx_switch returns we are back in the processor coroutine
[9f575ea]	445
[ac12f1f]	446	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_dst->canary );
[210b8b3]	447	/* 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 );
	448	/* paranoid */ verifyf( ((uintptr_t)thrd_dst->context.SP) < ((uintptr_t)__get_stack(thrd_dst->curr_cor)->base ), "ERROR : Destination $thread %p has been corrupted.\n StackPointer too small.\n", thrd_dst );
[b4b63e8]	449	/* paranoid */ verify( thrd_dst->context.SP );
[9d6e1b8a]	450	/* paranoid */ verify( thrd_dst->curr_cluster == this->cltr );
[8fc652e0]	451	/* paranoid */ verify( kernelTLS().this_thread == thrd_dst );
	452	/* paranoid */ verify( ! __preemption_enabled() );
[75f3522]	453
[58d64a4]	454	// Reset global state
[8fc652e0]	455	kernelTLS().this_thread = 0p;
[3381ed7]	456
	457	// We just finished running a thread, there are a few things that could have happened.
	458	// 1 - Regular case : the thread has blocked and now one has scheduled it yet.
	459	// 2 - Racy case : the thread has blocked but someone has already tried to schedule it.
	460	// 4 - Preempted
	461	// In case 1, we may have won a race so we can't write to the state again.
	462	// In case 2, we lost the race so we now own the thread.
	463
	464	if(unlikely(thrd_dst->preempted != __NO_PREEMPTION)) {
	465	// The thread was preempted, reschedule it and reset the flag
[254ad1b]	466	schedule_thread$( thrd_dst );
[3381ed7]	467	break RUNNING;
	468	}
[75f3522]	469
[3ea8ad1]	470	if(unlikely(thrd_dst->state == Halting)) {
[ff79d5e]	471	// The thread has halted, it should never be scheduled/run again
[5afb49a]	472	// finish the thread
	473	__thread_finish( thrd_dst );
[ff79d5e]	474	break RUNNING;
	475	}
	476
	477	/* paranoid */ verify( thrd_dst->state == Active );
	478	thrd_dst->state = Blocked;
	479
[3381ed7]	480	// set state of processor coroutine to active and the thread to inactive
[ff79d5e]	481	int old_ticket = __atomic_fetch_sub(&thrd_dst->ticket, 1, __ATOMIC_SEQ_CST);
	482	switch(old_ticket) {
[6a77224]	483	case TICKET_RUNNING:
[3381ed7]	484	// This is case 1, the regular case, nothing more is needed
	485	break RUNNING;
[6a77224]	486	case TICKET_UNBLOCK:
[ec43cf9]	487	#if !defined(__CFA_NO_STATISTICS__)
	488	__tls_stats()->ready.threads.threads++;
[73f4d08]	489	__push_stat( __tls_stats(), __tls_stats()->ready.threads.threads, false, "Processor", this );
[ec43cf9]	490	#endif
[3381ed7]	491	// This is case 2, the racy case, someone tried to run this thread before it finished blocking
	492	// In this case, just run it again.
	493	continue RUNNING;
	494	default:
	495	// This makes no sense, something is wrong abort
[ff79d5e]	496	abort();
[3381ed7]	497	}
[9f575ea]	498	}
[e8e457e]	499
[9f575ea]	500	// Just before returning to the processor, set the processor coroutine to active
[e8e457e]	501	proc_cor->state = Active;
[1eb239e4]	502
[dddb3dd0]	503	__cfadbg_print_safe(runtime_core, "Kernel : core %p finished running thread %p\n", this, thrd_dst);
	504
[ec43cf9]	505	#if !defined(__CFA_NO_STATISTICS__)
	506	__tls_stats()->ready.threads.threads--;
[73f4d08]	507	__push_stat( __tls_stats(), __tls_stats()->ready.threads.threads, false, "Processor", this );
[ec43cf9]	508	#endif
	509
[8fc652e0]	510	/* paranoid */ verify( ! __preemption_enabled() );
[82c948c]	511	}
	512
[14a61b5]	513	// KERNEL_ONLY
[b0c7419]	514	void returnToKernel() {
[8fc652e0]	515	/* paranoid */ verify( ! __preemption_enabled() );
	516	$coroutine * proc_cor = get_coroutine(kernelTLS().this_processor->runner);
	517	$thread * thrd_src = kernelTLS().this_thread;
[e8e457e]	518
[89eff25]	519	__STATS( thrd_src->last_proc = kernelTLS().this_processor; )
[29cb302]	520
[9f575ea]	521	// Run the thread on this processor
	522	{
	523	int local_errno = *__volatile_errno();
	524	#if defined( __i386 ) \|\| defined( __x86_64 )
	525	__x87_store;
	526	#endif
[b4b63e8]	527	/* paranoid */ verify( proc_cor->context.SP );
[ac12f1f]	528	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_src->canary );
[c7a900a]	529	__cfactx_switch( &thrd_src->context, &proc_cor->context );
[ac12f1f]	530	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_src->canary );
[9f575ea]	531	#if defined( __i386 ) \|\| defined( __x86_64 )
	532	__x87_load;
	533	#endif
	534	*__volatile_errno() = local_errno;
[8fcbb4c]	535	}
[deca0f5]	536
[29cb302]	537	#if !defined(__CFA_NO_STATISTICS__)
[89eff25]	538	/* paranoid */ verify( thrd_src->last_proc != 0p );
	539	if(thrd_src->last_proc != kernelTLS().this_processor) {
[29cb302]	540	__tls_stats()->ready.threads.migration++;
	541	}
	542	#endif
	543
[8fc652e0]	544	/* paranoid */ verify( ! __preemption_enabled() );
[210b8b3]	545	/* 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 );
	546	/* 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]	547	}
	548
[8def349]	549	//-----------------------------------------------------------------------------
	550	// Scheduler routines
[14a61b5]	551	// KERNEL ONLY
[e9c0b4c]	552	static void __schedule_thread( $thread * thrd ) {
[8fc652e0]	553	/* paranoid */ verify( ! __preemption_enabled() );
[254ad1b]	554	/* paranoid */ verify( ready_schedule_islocked());
[6a490b2]	555	/* paranoid */ verify( thrd );
	556	/* paranoid */ verify( thrd->state != Halted );
[9d6e1b8a]	557	/* paranoid */ verify( thrd->curr_cluster );
[3381ed7]	558	/* paranoid */ #if defined( __CFA_WITH_VERIFY__ )
[504a7dc]	559	/* paranoid */ if( thrd->state == Blocked \|\| thrd->state == Start ) assertf( thrd->preempted == __NO_PREEMPTION,
	560	"Error inactive thread marked as preempted, state %d, preemption %d\n", thrd->state, thrd->preempted );
[ff79d5e]	561	/* paranoid */ if( thrd->preempted != __NO_PREEMPTION ) assertf(thrd->state == Active,
[504a7dc]	562	"Error preempted thread marked as not currently running, state %d, preemption %d\n", thrd->state, thrd->preempted );
[3381ed7]	563	/* paranoid */ #endif
[6a490b2]	564	/* paranoid */ verifyf( thrd->link.next == 0p, "Expected null got %p", thrd->link.next );
[ac12f1f]	565	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd->canary );
[b4b63e8]	566
[9f575ea]	567
[ae7be7a]	568	if (thrd->preempted == __NO_PREEMPTION) thrd->state = Ready;
[6b4cdd3]	569
[ec43cf9]	570	// Dereference the thread now because once we push it, there is not guaranteed it's still valid.
	571	struct cluster * cl = thrd->curr_cluster;
[89eff25]	572	__STATS(bool outside = thrd->last_proc && thrd->last_proc != kernelTLS().this_processor; )
[32a8b61]	573
[254ad1b]	574	// push the thread to the cluster ready-queue
	575	push( cl, thrd );
[32a8b61]	576
[254ad1b]	577	// variable thrd is no longer safe to use
[734908c]	578	thrd = 0xdeaddeaddeaddeadp;
[32a8b61]	579
[254ad1b]	580	// wake the cluster using the save variable.
	581	__wake_one( cl );
[1c273d0]	582
[ec43cf9]	583	#if !defined(__CFA_NO_STATISTICS__)
	584	if( kernelTLS().this_stats ) {
	585	__tls_stats()->ready.threads.threads++;
[89eff25]	586	if(outside) {
	587	__tls_stats()->ready.threads.extunpark++;
	588	}
[73f4d08]	589	__push_stat( __tls_stats(), __tls_stats()->ready.threads.threads, false, "Processor", kernelTLS().this_processor );
[ec43cf9]	590	}
	591	else {
	592	__atomic_fetch_add(&cl->stats->ready.threads.threads, 1, __ATOMIC_RELAXED);
[89eff25]	593	__atomic_fetch_add(&cl->stats->ready.threads.extunpark, 1, __ATOMIC_RELAXED);
[73f4d08]	594	__push_stat( cl->stats, cl->stats->ready.threads.threads, true, "Cluster", cl );
[ec43cf9]	595	}
	596	#endif
	597
[254ad1b]	598	/* paranoid */ verify( ready_schedule_islocked());
[8fc652e0]	599	/* paranoid */ verify( ! __preemption_enabled() );
[db6f06a]	600	}
	601
[254ad1b]	602	void schedule_thread$( $thread * thrd ) {
	603	ready_schedule_lock();
	604	__schedule_thread( thrd );
	605	ready_schedule_unlock();
	606	}
	607
[14a61b5]	608	// KERNEL ONLY
[1eb239e4]	609	static inline $thread * __next_thread(cluster * this) with( *this ) {
[8fc652e0]	610	/* paranoid */ verify( ! __preemption_enabled() );
[7768b8d]	611
[e873838]	612	ready_schedule_lock();
[431cd4f]	613	$thread * thrd = pop_fast( this );
[e873838]	614	ready_schedule_unlock();
[7768b8d]	615
[8fc652e0]	616	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	617	return thrd;
[eb2e723]	618	}
	619
[64a7146]	620	// KERNEL ONLY
[1eb239e4]	621	static inline $thread * __next_thread_slow(cluster * this) with( *this ) {
[8fc652e0]	622	/* paranoid */ verify( ! __preemption_enabled() );
[64a7146]	623
[e873838]	624	ready_schedule_lock();
[fc59df78]	625	$thread * thrd;
	626	for(25) {
	627	thrd = pop_slow( this );
	628	if(thrd) goto RET;
	629	}
	630	thrd = pop_search( this );
	631
	632	RET:
[e873838]	633	ready_schedule_unlock();
[64a7146]	634
[8fc652e0]	635	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	636	return thrd;
[64a7146]	637	}
	638
[c6c7e6c]	639	static inline bool __must_unpark( $thread * thrd ) {
[ff79d5e]	640	int old_ticket = __atomic_fetch_add(&thrd->ticket, 1, __ATOMIC_SEQ_CST);
	641	switch(old_ticket) {
[6a77224]	642	case TICKET_RUNNING:
[3381ed7]	643	// Wake won the race, the thread will reschedule/rerun itself
[c6c7e6c]	644	return false;
[6a77224]	645	case TICKET_BLOCKED:
[3381ed7]	646	/* paranoid */ verify( ! thrd->preempted != __NO_PREEMPTION );
[ff79d5e]	647	/* paranoid */ verify( thrd->state == Blocked );
[c6c7e6c]	648	return true;
[3381ed7]	649	default:
	650	// This makes no sense, something is wrong abort
[7ee8153]	651	abort("Thread %p (%s) has mismatch park/unpark\n", thrd, thrd->self_cor.name);
[de6319f]	652	}
[eb2e723]	653	}
	654
[e9c0b4c]	655	void __kernel_unpark( $thread * thrd ) {
	656	/* paranoid */ verify( ! __preemption_enabled() );
	657	/* paranoid */ verify( ready_schedule_islocked());
	658
	659	if( !thrd ) return;
	660
	661	if(__must_unpark(thrd)) {
	662	// Wake lost the race,
	663	__schedule_thread( thrd );
	664	}
	665
	666	/* paranoid */ verify( ready_schedule_islocked());
	667	/* paranoid */ verify( ! __preemption_enabled() );
	668	}
	669
[c6c7e6c]	670	void unpark( $thread * thrd ) {
	671	if( !thrd ) return;
[0b33412]	672
[c6c7e6c]	673	if(__must_unpark(thrd)) {
	674	disable_interrupts();
[a3821fa]	675	// Wake lost the race,
[254ad1b]	676	schedule_thread$( thrd );
[a3821fa]	677	enable_interrupts(false);
[de6319f]	678	}
[eb2e723]	679	}
[0b33412]	680
[e235429]	681	void park( void ) {
[a3821fa]	682	__disable_interrupts_checked();
	683	/* paranoid */ verify( kernelTLS().this_thread->preempted == __NO_PREEMPTION );
	684	returnToKernel();
	685	__enable_interrupts_checked();
[0c78741]	686
	687	}
[09800e9]	688
[5afb49a]	689	extern "C" {
	690	// Leave the thread monitor
	691	// last routine called by a thread.
	692	// Should never return
	693	void __cfactx_thrd_leave() {
[8fc652e0]	694	$thread * thrd = active_thread();
[5afb49a]	695	$monitor * this = &thrd->self_mon;
	696
	697	// Lock the monitor now
	698	lock( this->lock __cfaabi_dbg_ctx2 );
	699
	700	disable_interrupts();
	701
[9d6e1b8a]	702	/* paranoid */ verify( ! __preemption_enabled() );
	703	/* paranoid */ verify( thrd->state == Active );
	704	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd->canary );
	705	/* paranoid */ verify( kernelTLS().this_thread == thrd );
	706	/* paranoid */ verify( thrd->context.SP );
	707	/* 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 );
	708	/* 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 );
	709
[3ea8ad1]	710	thrd->state = Halting;
[58688bf]	711	if( TICKET_RUNNING != thrd->ticket ) { abort( "Thread terminated with pending unpark" ); }
[9d6e1b8a]	712	if( thrd != this->owner ) { abort( "Thread internal monitor has incorrect owner" ); }
	713	if( this->recursion != 1) { abort( "Thread internal monitor has unbalanced recursion" ); }
[5afb49a]	714
	715	// Leave the thread
	716	returnToKernel();
	717
	718	// Control flow should never reach here!
[9d6e1b8a]	719	abort();
[5afb49a]	720	}
[09800e9]	721	}
	722
[14a61b5]	723	// KERNEL ONLY
[3381ed7]	724	bool force_yield( __Preemption_Reason reason ) {
[a3821fa]	725	__disable_interrupts_checked();
	726	$thread * thrd = kernelTLS().this_thread;
	727	/* paranoid */ verify(thrd->state == Active);
	728
	729	// SKULLDUGGERY: It is possible that we are preempting this thread just before
	730	// it was going to park itself. If that is the case and it is already using the
	731	// intrusive fields then we can't use them to preempt the thread
	732	// If that is the case, abandon the preemption.
	733	bool preempted = false;
	734	if(thrd->link.next == 0p) {
	735	preempted = true;
	736	thrd->preempted = reason;
	737	returnToKernel();
	738	}
	739	__enable_interrupts_checked( false );
[3381ed7]	740	return preempted;
[f2b12406]	741	}
	742
[14a61b5]	743	//=============================================================================================
[92e7631]	744	// Kernel Idle Sleep
[14a61b5]	745	//=============================================================================================
[64a7146]	746	// Wake a thread from the front if there are any
[e873838]	747	static void __wake_one(cluster * this) {
[8fc652e0]	748	/* paranoid */ verify( ! __preemption_enabled() );
[e873838]	749	/* paranoid */ verify( ready_schedule_islocked() );
[14a61b5]	750
[64a7146]	751	// Check if there is a sleeping processor
[1eb239e4]	752	processor * p;
	753	unsigned idle;
	754	unsigned total;
[6a9b12b]	755	[idle, total, p] = query_idles(this->procs);
[14a61b5]	756
[64a7146]	757	// If no one is sleeping, we are done
[1eb239e4]	758	if( idle == 0 ) return;
[14a61b5]	759
[64a7146]	760	// We found a processor, wake it up
[dddb3dd0]	761	eventfd_t val;
	762	val = 1;
	763	eventfd_write( p->idle, val );
[14a61b5]	764
[1eb239e4]	765	#if !defined(__CFA_NO_STATISTICS__)
[5cb51502]	766	if( kernelTLS().this_stats ) {
	767	__tls_stats()->ready.sleep.wakes++;
	768	}
	769	else {
	770	__atomic_fetch_add(&this->stats->ready.sleep.wakes, 1, __ATOMIC_RELAXED);
	771	}
[1eb239e4]	772	#endif
	773
[e873838]	774	/* paranoid */ verify( ready_schedule_islocked() );
[8fc652e0]	775	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	776
	777	return;
[64a7146]	778	}
[14a61b5]	779
[64a7146]	780	// Unconditionnaly wake a thread
[1eb239e4]	781	void __wake_proc(processor * this) {
[64a7146]	782	__cfadbg_print_safe(runtime_core, "Kernel : waking Processor %p\n", this);
[14a61b5]	783
[a3821fa]	784	__disable_interrupts_checked();
[8fc652e0]	785	/* paranoid */ verify( ! __preemption_enabled() );
[dddb3dd0]	786	eventfd_t val;
	787	val = 1;
[55d6affb]	788	eventfd_write( this->idle, val );
[a3821fa]	789	__enable_interrupts_checked();
[92e7631]	790	}
	791
[6a9b12b]	792	static void mark_idle(__cluster_proc_list & this, processor & proc) {
[8fc652e0]	793	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	794	lock( this );
	795	this.idle++;
	796	/* paranoid */ verify( this.idle <= this.total );
[fc59b580]	797	remove(proc);
[6a9b12b]	798	insert_first(this.idles, proc);
[1eb239e4]	799	unlock( this );
[8fc652e0]	800	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	801	}
[8e16177]	802
[6a9b12b]	803	static void mark_awake(__cluster_proc_list & this, processor & proc) {
[8fc652e0]	804	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	805	lock( this );
	806	this.idle--;
	807	/* paranoid */ verify( this.idle >= 0 );
	808	remove(proc);
[fc59b580]	809	insert_last(this.actives, proc);
[1eb239e4]	810	unlock( this );
[8fc652e0]	811	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	812	}
[c34ebf2]	813
[6a9b12b]	814	static [unsigned idle, unsigned total, * processor] query_idles( & __cluster_proc_list this ) {
	815	/* paranoid */ verify( ! __preemption_enabled() );
	816	/* paranoid */ verify( ready_schedule_islocked() );
	817
[1eb239e4]	818	for() {
	819	uint64_t l = __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST);
	820	if( 1 == (l % 2) ) { Pause(); continue; }
	821	unsigned idle = this.idle;
	822	unsigned total = this.total;
[6a9b12b]	823	processor * proc = &this.idles`first;
[7fdae38]	824	// Compiler fence is unnecessary, but gcc-8 and older incorrectly reorder code without it
	825	asm volatile("": : :"memory");
[1eb239e4]	826	if(l != __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST)) { Pause(); continue; }
	827	return [idle, total, proc];
	828	}
[6a9b12b]	829
	830	/* paranoid */ verify( ready_schedule_islocked() );
	831	/* paranoid */ verify( ! __preemption_enabled() );
[6b4cdd3]	832	}
	833
[dbe9b08]	834	//=============================================================================================
	835	// Unexpected Terminating logic
	836	//=============================================================================================
[92bfda0]	837	void __kernel_abort_msg( char * abort_text, int abort_text_size ) {
	838	$thread * thrd = __cfaabi_tls.this_thread;
[9d944b2]	839
[de94a60]	840	if(thrd) {
	841	int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
[1c40091]	842	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[de94a60]	843
[212c2187]	844	if ( &thrd->self_cor != thrd->curr_cor ) {
	845	len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
[1c40091]	846	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[de94a60]	847	}
	848	else {
[1c40091]	849	__cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
[de94a60]	850	}
[1c273d0]	851	}
[9d944b2]	852	else {
[de94a60]	853	int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
[1c40091]	854	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[9d944b2]	855	}
	856	}
	857
[92bfda0]	858	int __kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
	859	return get_coroutine(__cfaabi_tls.this_thread) == get_coroutine(mainThread) ? 4 : 2;
[2b8bc41]	860	}
	861
[de94a60]	862	static __spinlock_t kernel_debug_lock;
	863
[9d944b2]	864	extern "C" {
[1c40091]	865	void __cfaabi_bits_acquire() {
[36982fc]	866	lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
[9d944b2]	867	}
	868
[1c40091]	869	void __cfaabi_bits_release() {
[ea7d2b0]	870	unlock( kernel_debug_lock );
[9d944b2]	871	}
[8118303]	872	}
	873
[fa21ac9]	874	//=============================================================================================
	875	// Kernel Utilities
	876	//=============================================================================================
[dddb3dd0]	877	#if defined(CFA_HAVE_LINUX_IO_URING_H)
	878	#include "io/types.hfa"
	879	#endif
	880
[c1c95b1]	881	static inline bool __maybe_io_drain( processor * proc ) {
[e9c0b4c]	882	bool ret = false;
[dddb3dd0]	883	#if defined(CFA_HAVE_LINUX_IO_URING_H)
	884	__cfadbg_print_safe(runtime_core, "Kernel : core %p checking io for ring %d\n", proc, proc->io.ctx->fd);
	885
	886	// Check if we should drain the queue
	887	$io_context * ctx = proc->io.ctx;
	888	unsigned head = *ctx->cq.head;
	889	unsigned tail = *ctx->cq.tail;
[c1c95b1]	890	if(head == tail) return false;
[b7fd2db6]	891	ready_schedule_lock();
[e9c0b4c]	892	ret = __cfa_io_drain( proc );
[b7fd2db6]	893	ready_schedule_unlock();
[dddb3dd0]	894	#endif
[e9c0b4c]	895	return ret;
[dddb3dd0]	896	}
	897
[de94a60]	898	//-----------------------------------------------------------------------------
	899	// Debug
	900	__cfaabi_dbg_debug_do(
[1997b4e]	901	extern "C" {
[ae66348]	902	void __cfaabi_dbg_record_lock(__spinlock_t & this, const char prev_name[]) {
[1997b4e]	903	this.prev_name = prev_name;
[8fc652e0]	904	this.prev_thrd = kernelTLS().this_thread;
[1997b4e]	905	}
[9181f1d]	906	}
[f7d6bb0]	907	)
[2026bb6]	908
	909	//-----------------------------------------------------------------------------
	910	// Debug
[8c50aed]	911	bool threading_enabled(void) __attribute__((const)) {
[2026bb6]	912	return true;
	913	}
[c34ebf2]	914
	915	//-----------------------------------------------------------------------------
	916	// Statistics
	917	#if !defined(__CFA_NO_STATISTICS__)
	918	void print_halts( processor & this ) {
	919	this.print_halts = true;
	920	}
[58688bf]	921
	922	void print_stats_now( cluster & this, int flags ) {
[1b033b8]	923	__print_stats( this.stats, this.print_stats, "Cluster", this.name, (void*)&this );
	924	}
[c34ebf2]	925	#endif
[8118303]	926	// Local Variables: //
	927	// mode: c //
	928	// tab-width: 4 //
	929	// End: //

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