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ADT ast-experimental enum forall-pointer-decay pthread-emulation qualifiedEnum

Last change on this file since 7e7a076 was 445f984, checked in by Thierry Delisle <tdelisle@…>, 4 years ago
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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__
[43784ac]	17	#define _GNU_SOURCE
	18
[4069faad]	19	// #define __CFA_DEBUG_PRINT_RUNTIME_CORE__
[2026bb6]	20
[8118303]	21	//C Includes
[214e8da]	22	#include <errno.h>
[9d944b2]	23	#include <stdio.h>
[445f984]	24	#include <string.h>
[58b6d1b]	25	#include <signal.h>
[9d944b2]	26	#include <unistd.h>
[dddb3dd0]	27	extern "C" {
	28	#include <sys/eventfd.h>
	29	}
[8118303]	30
	31	//CFA Includes
[73abe95]	32	#include "kernel_private.hfa"
	33	#include "preemption.hfa"
[445f984]	34	#include "strstream.hfa"
	35	#include "device/cpu.hfa"
[8118303]	36
	37	//Private includes
	38	#define __CFA_INVOKE_PRIVATE__
	39	#include "invoke.h"
	40
[89eff25]	41	#if !defined(__CFA_NO_STATISTICS__)
	42	#define __STATS( ...) __VA_ARGS__
	43	#else
	44	#define __STATS( ...)
	45	#endif
[4069faad]	46
[deca0f5]	47	//-----------------------------------------------------------------------------
	48	// Some assembly required
[1805b1b]	49	#if defined( __i386 )
[deca0f5]	50	// mxcr : SSE Status and Control bits (control bits are preserved across function calls)
	51	// fcw : X87 FPU control word (preserved across function calls)
	52	#define __x87_store \
	53	uint32_t __mxcr; \
	54	uint16_t __fcw; \
	55	__asm__ volatile ( \
	56	"stmxcsr %0\n" \
	57	"fnstcw %1\n" \
	58	: "=m" (__mxcr),\
	59	"=m" (__fcw) \
	60	)
	61
	62	#define __x87_load \
	63	__asm__ volatile ( \
	64	"fldcw %1\n" \
	65	"ldmxcsr %0\n" \
	66	::"m" (__mxcr),\
	67	"m" (__fcw) \
	68	)
	69
	70	#elif defined( __x86_64 )
	71	#define __x87_store \
	72	uint32_t __mxcr; \
	73	uint16_t __fcw; \
	74	__asm__ volatile ( \
	75	"stmxcsr %0\n" \
	76	"fnstcw %1\n" \
	77	: "=m" (__mxcr),\
	78	"=m" (__fcw) \
	79	)
	80
	81	#define __x87_load \
	82	__asm__ volatile ( \
	83	"fldcw %1\n" \
	84	"ldmxcsr %0\n" \
	85	:: "m" (__mxcr),\
	86	"m" (__fcw) \
	87	)
	88
[0190480]	89	#elif defined( __arm__ )
	90	#define __x87_store
	91	#define __x87_load
	92
	93	#elif defined( __aarch64__ )
[74f5c83]	94	#define __x87_store \
	95	uint32_t __fpcntl[2]; \
	96	__asm__ volatile ( \
	97	"mrs x9, FPCR\n" \
	98	"mrs x10, FPSR\n" \
	99	"stp x9, x10, %0\n" \
	100	: "=m" (__fpcntl) : : "x9", "x10" \
	101	)
	102
	103	#define __x87_load \
	104	__asm__ volatile ( \
	105	"ldp x9, x10, %0\n" \
	106	"msr FPSR, x10\n" \
	107	"msr FPCR, x9\n" \
	108	: "=m" (__fpcntl) : : "x9", "x10" \
	109	)
	110
[deca0f5]	111	#else
[0190480]	112	#error unsupported hardware architecture
[deca0f5]	113	#endif
	114
[e84ab3d]	115	extern thread$ * mainThread;
[e660761]	116	extern processor * mainProcessor;
[2ac095d]	117
[92e7631]	118	//-----------------------------------------------------------------------------
	119	// Kernel Scheduling logic
[e84ab3d]	120	static thread$ * __next_thread(cluster * this);
	121	static thread$ * __next_thread_slow(cluster * this);
	122	static inline bool __must_unpark( thread$ * thrd ) __attribute((nonnull(1)));
	123	static void __run_thread(processor * this, thread$ * dst);
[e873838]	124	static void __wake_one(cluster * cltr);
[1eb239e4]	125
[6a9b12b]	126	static void mark_idle (__cluster_proc_list & idles, processor & proc);
	127	static void mark_awake(__cluster_proc_list & idles, processor & proc);
	128	static [unsigned idle, unsigned total, * processor] query_idles( & __cluster_proc_list idles );
[1eb239e4]	129
[dddb3dd0]	130	extern void __cfa_io_start( processor * );
[c1c95b1]	131	extern bool __cfa_io_drain( processor * );
[dddb3dd0]	132	extern void __cfa_io_flush( processor * );
	133	extern void __cfa_io_stop ( processor * );
[c1c95b1]	134	static inline bool __maybe_io_drain( processor * );
[dddb3dd0]	135
	136	extern void __disable_interrupts_hard();
	137	extern void __enable_interrupts_hard();
[c84e80a]	138
[a3821fa]	139	static inline void __disable_interrupts_checked() {
	140	/* paranoid */ verify( __preemption_enabled() );
	141	disable_interrupts();
	142	/* paranoid */ verify( ! __preemption_enabled() );
	143	}
	144
	145	static inline void __enable_interrupts_checked( bool poll = true ) {
	146	/* paranoid */ verify( ! __preemption_enabled() );
	147	enable_interrupts( poll );
	148	/* paranoid */ verify( __preemption_enabled() );
	149	}
	150
[75f3522]	151	//=============================================================================================
	152	// Kernel Scheduling logic
	153	//=============================================================================================
[8fcbb4c]	154	//Main of the processor contexts
[83a071f9]	155	void main(processorCtx_t & runner) {
[21184e3]	156	// Because of a bug, we couldn't initialized the seed on construction
	157	// Do it here
[8fc652e0]	158	__cfaabi_tls.rand_seed ^= rdtscl();
	159	__cfaabi_tls.ready_rng.fwd_seed = 25214903917_l64u * (rdtscl() ^ (uintptr_t)&runner);
[f2384c9a]	160	__tls_rand_advance_bck();
[21184e3]	161
[83a071f9]	162	processor * this = runner.proc;
[094476d]	163	verify(this);
[c81ebf9]	164
[dddb3dd0]	165	__cfa_io_start( this );
	166
[4069faad]	167	__cfadbg_print_safe(runtime_core, "Kernel : core %p starting\n", this);
[28d73c1]	168	#if !defined(__CFA_NO_STATISTICS__)
	169	if( this->print_halts ) {
[c993b15]	170	__cfaabi_bits_print_safe( STDOUT_FILENO, "Processor : %d - %s (%p)\n", this->unique_id, this->name, (void*)this);
[28d73c1]	171	}
	172	#endif
[b798713]	173
[75f3522]	174	{
[c81ebf9]	175	// Setup preemption data
	176	preemption_scope scope = { this };
	177
[a5e7233]	178	// if we need to run some special setup, now is the time to do it.
	179	if(this->init.thrd) {
	180	this->init.thrd->curr_cluster = this->cltr;
	181	__run_thread(this, this->init.thrd);
	182	}
[325e6ea]	183
[4069faad]	184	__cfadbg_print_safe(runtime_core, "Kernel : core %p started\n", this);
[8118303]	185
[e84ab3d]	186	thread$ * readyThread = 0p;
[1eb239e4]	187	MAIN_LOOP:
	188	for() {
[57f70ab]	189	#define OLD_MAIN 1
	190	#if OLD_MAIN
[dddb3dd0]	191	// Check if there is pending io
	192	__maybe_io_drain( this );
	193
[92e7631]	194	// Try to get the next thread
[8c50aed]	195	readyThread = __next_thread( this->cltr );
[75f3522]	196
[1eb239e4]	197	if( !readyThread ) {
[dddb3dd0]	198	__cfa_io_flush( this );
[1eb239e4]	199	readyThread = __next_thread_slow( this->cltr );
	200	}
[4e6fb8e]	201
[1eb239e4]	202	HALT:
	203	if( !readyThread ) {
	204	// Don't block if we are done
	205	if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
[c81ebf9]	206
[1eb239e4]	207	#if !defined(__CFA_NO_STATISTICS__)
	208	__tls_stats()->ready.sleep.halts++;
	209	#endif
[398e8e9]	210
[1eb239e4]	211	// Push self to idle stack
[6a9b12b]	212	mark_idle(this->cltr->procs, * this);
[398e8e9]	213
[1eb239e4]	214	// Confirm the ready-queue is empty
	215	readyThread = __next_thread_slow( this->cltr );
	216	if( readyThread ) {
	217	// A thread was found, cancel the halt
[6a9b12b]	218	mark_awake(this->cltr->procs, * this);
[1eb239e4]	219
	220	#if !defined(__CFA_NO_STATISTICS__)
	221	__tls_stats()->ready.sleep.cancels++;
	222	#endif
	223
	224	// continue the mai loop
	225	break HALT;
	226	}
	227
	228	#if !defined(__CFA_NO_STATISTICS__)
	229	if(this->print_halts) {
[c993b15]	230	__cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 0\n", this->unique_id, rdtscl());
[1eb239e4]	231	}
	232	#endif
	233
[dddb3dd0]	234	__cfadbg_print_safe(runtime_core, "Kernel : core %p waiting on eventfd %d\n", this, this->idle);
	235
[56e5b24]	236	{
	237	eventfd_t val;
	238	ssize_t ret = read( this->idle, &val, sizeof(val) );
	239	if(ret < 0) {
	240	switch((int)errno) {
	241	case EAGAIN:
	242	#if EAGAIN != EWOULDBLOCK
	243	case EWOULDBLOCK:
	244	#endif
	245	case EINTR:
	246	// No need to do anything special here, just assume it's a legitimate wake-up
	247	break;
	248	default:
	249	abort( "KERNEL : internal error, read failure on idle eventfd, error(%d) %s.", (int)errno, strerror( (int)errno ) );
	250	}
	251	}
	252	}
[1eb239e4]	253
	254	#if !defined(__CFA_NO_STATISTICS__)
	255	if(this->print_halts) {
[c993b15]	256	__cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 1\n", this->unique_id, rdtscl());
[1eb239e4]	257	}
	258	#endif
	259
	260	// We were woken up, remove self from idle
[6a9b12b]	261	mark_awake(this->cltr->procs, * this);
[1eb239e4]	262
	263	// DON'T just proceed, start looking again
	264	continue MAIN_LOOP;
[64a7146]	265	}
[1eb239e4]	266
	267	/* paranoid */ verify( readyThread );
	268
[dddb3dd0]	269	// Reset io dirty bit
	270	this->io.dirty = false;
	271
[1eb239e4]	272	// We found a thread run it
	273	__run_thread(this, readyThread);
	274
	275	// Are we done?
	276	if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
[325e6ea]	277
[dddb3dd0]	278	if(this->io.pending && !this->io.dirty) {
	279	__cfa_io_flush( this );
	280	}
[89eff25]	281
[34b2796]	282	#else
[57f70ab]	283	#warning new kernel loop
[34b2796]	284	SEARCH: {
	285	/* paranoid */ verify( ! __preemption_enabled() );
	286
	287	// First, lock the scheduler since we are searching for a thread
	288	ready_schedule_lock();
	289
	290	// Try to get the next thread
	291	readyThread = pop_fast( this->cltr );
	292	if(readyThread) { ready_schedule_unlock(); break SEARCH; }
	293
	294	// If we can't find a thread, might as well flush any outstanding I/O
	295	if(this->io.pending) { __cfa_io_flush( this ); }
	296
	297	// Spin a little on I/O, just in case
[12daa43]	298	for(5) {
[34b2796]	299	__maybe_io_drain( this );
	300	readyThread = pop_fast( this->cltr );
	301	if(readyThread) { ready_schedule_unlock(); break SEARCH; }
	302	}
	303
	304	// no luck, try stealing a few times
[12daa43]	305	for(5) {
[34b2796]	306	if( __maybe_io_drain( this ) ) {
	307	readyThread = pop_fast( this->cltr );
	308	} else {
	309	readyThread = pop_slow( this->cltr );
	310	}
	311	if(readyThread) { ready_schedule_unlock(); break SEARCH; }
	312	}
	313
	314	// still no luck, search for a thread
	315	readyThread = pop_search( this->cltr );
	316	if(readyThread) { ready_schedule_unlock(); break SEARCH; }
	317
	318	// Don't block if we are done
	319	if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
	320
	321	__STATS( __tls_stats()->ready.sleep.halts++; )
	322
	323	// Push self to idle stack
	324	ready_schedule_unlock();
	325	mark_idle(this->cltr->procs, * this);
	326	ready_schedule_lock();
	327
	328	// Confirm the ready-queue is empty
	329	__maybe_io_drain( this );
	330	readyThread = pop_search( this->cltr );
	331	ready_schedule_unlock();
	332
	333	if( readyThread ) {
	334	// A thread was found, cancel the halt
	335	mark_awake(this->cltr->procs, * this);
	336
	337	__STATS( __tls_stats()->ready.sleep.cancels++; )
	338
	339	// continue the main loop
	340	break SEARCH;
	341	}
	342
[fb4ccdf]	343	__STATS( if(this->print_halts) __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 0\n", this->unique_id, rdtscl()); )
[34b2796]	344	__cfadbg_print_safe(runtime_core, "Kernel : core %p waiting on eventfd %d\n", this, this->idle);
	345
	346	// __disable_interrupts_hard();
	347	eventfd_t val;
	348	eventfd_read( this->idle, &val );
	349	// __enable_interrupts_hard();
	350
[fb4ccdf]	351	__STATS( if(this->print_halts) __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 1\n", this->unique_id, rdtscl()); )
[34b2796]	352
	353	// We were woken up, remove self from idle
	354	mark_awake(this->cltr->procs, * this);
	355
	356	// DON'T just proceed, start looking again
	357	continue MAIN_LOOP;
	358	}
	359
	360	RUN_THREAD:
	361	/* paranoid */ verify( ! __preemption_enabled() );
	362	/* paranoid */ verify( readyThread );
	363
	364	// Reset io dirty bit
	365	this->io.dirty = false;
	366
	367	// We found a thread run it
	368	__run_thread(this, readyThread);
	369
	370	// Are we done?
	371	if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
	372
	373	if(this->io.pending && !this->io.dirty) {
	374	__cfa_io_flush( this );
	375	}
	376
	377	ready_schedule_lock();
	378	__maybe_io_drain( this );
	379	ready_schedule_unlock();
	380	#endif
[c81ebf9]	381	}
	382
[4069faad]	383	__cfadbg_print_safe(runtime_core, "Kernel : core %p stopping\n", this);
[c84e80a]	384	}
[8118303]	385
[dddb3dd0]	386	__cfa_io_stop( this );
	387
[454f478]	388	post( this->terminated );
[bdeba0b]	389
[28d73c1]	390	if(this == mainProcessor) {
[6a490b2]	391	// HACK : the coroutine context switch expects this_thread to be set
	392	// and it make sense for it to be set in all other cases except here
	393	// fake it
[8fc652e0]	394	__cfaabi_tls.this_thread = mainThread;
[6a490b2]	395	}
[7768b8d]	396
[4069faad]	397	__cfadbg_print_safe(runtime_core, "Kernel : core %p terminated\n", this);
[c84e80a]	398	}
	399
[5c1a531]	400	static int * __volatile_errno() __attribute__((noinline));
	401	static int * __volatile_errno() { asm(""); return &errno; }
	402
[14a61b5]	403	// KERNEL ONLY
[1c273d0]	404	// runThread runs a thread by context switching
	405	// from the processor coroutine to the target thread
[e84ab3d]	406	static void __run_thread(processor * this, thread$ * thrd_dst) {
[8fc652e0]	407	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	408	/* paranoid */ verifyf( thrd_dst->state == Ready \|\| thrd_dst->preempted != __NO_PREEMPTION, "state : %d, preempted %d\n", thrd_dst->state, thrd_dst->preempted);
	409	/* paranoid */ verifyf( thrd_dst->link.next == 0p, "Expected null got %p", thrd_dst->link.next );
	410	__builtin_prefetch( thrd_dst->context.SP );
	411
[1f45c7d]	412	int curr = __kernel_getcpu();
	413	if(thrd_dst->last_cpu != curr) {
	414	int64_t l = thrd_dst->last_cpu;
	415	int64_t c = curr;
	416	int64_t v = (l << 32) \| c;
	417	__push_stat( __tls_stats(), v, false, "Processor", this );
	418	}
	419
	420	thrd_dst->last_cpu = curr;
	421
[dddb3dd0]	422	__cfadbg_print_safe(runtime_core, "Kernel : core %p running thread %p (%s)\n", this, thrd_dst, thrd_dst->self_cor.name);
	423
[e84ab3d]	424	coroutine$ * proc_cor = get_coroutine(this->runner);
[8fcbb4c]	425
[9f575ea]	426	// set state of processor coroutine to inactive
	427	verify(proc_cor->state == Active);
[ae7be7a]	428	proc_cor->state = Blocked;
[e8e457e]	429
[9f575ea]	430	// Actually run the thread
[3381ed7]	431	RUNNING: while(true) {
[ff79d5e]	432	thrd_dst->preempted = __NO_PREEMPTION;
	433	thrd_dst->state = Active;
[e8e457e]	434
[58d64a4]	435	// Update global state
[8fc652e0]	436	kernelTLS().this_thread = thrd_dst;
[75f3522]	437
[8fc652e0]	438	/* paranoid */ verify( ! __preemption_enabled() );
	439	/* paranoid */ verify( kernelTLS().this_thread == thrd_dst );
[9d6e1b8a]	440	/* paranoid */ verify( thrd_dst->curr_cluster == this->cltr );
[b4b63e8]	441	/* paranoid */ verify( thrd_dst->context.SP );
[5afb49a]	442	/* paranoid */ verify( thrd_dst->state != Halted );
[e84ab3d]	443	/* paranoid */ verifyf( ((uintptr_t)thrd_dst->context.SP) < ((uintptr_t)__get_stack(thrd_dst->curr_cor)->base ) \|\| thrd_dst->curr_cor == proc_cor \|\| thrd_dst->corctx_flag, "ERROR : Destination thread$ %p has been corrupted.\n StackPointer too small.\n", thrd_dst ); // add escape condition if we are setting up the processor
	444	/* paranoid */ verifyf( ((uintptr_t)thrd_dst->context.SP) > ((uintptr_t)__get_stack(thrd_dst->curr_cor)->limit) \|\| thrd_dst->curr_cor == proc_cor \|\| thrd_dst->corctx_flag, "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]	445	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_dst->canary );
[b4b63e8]	446
[3381ed7]	447
[58d64a4]	448
[9f575ea]	449	// set context switch to the thread that the processor is executing
[c7a900a]	450	__cfactx_switch( &proc_cor->context, &thrd_dst->context );
	451	// when __cfactx_switch returns we are back in the processor coroutine
[9f575ea]	452
[50871b4]	453
	454
[ac12f1f]	455	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_dst->canary );
[e84ab3d]	456	/* paranoid */ verifyf( ((uintptr_t)thrd_dst->context.SP) > ((uintptr_t)__get_stack(thrd_dst->curr_cor)->limit) \|\| thrd_dst->corctx_flag, "ERROR : Destination thread$ %p has been corrupted.\n StackPointer too large.\n", thrd_dst );
	457	/* paranoid */ verifyf( ((uintptr_t)thrd_dst->context.SP) < ((uintptr_t)__get_stack(thrd_dst->curr_cor)->base ) \|\| thrd_dst->corctx_flag, "ERROR : Destination thread$ %p has been corrupted.\n StackPointer too small.\n", thrd_dst );
[b4b63e8]	458	/* paranoid */ verify( thrd_dst->context.SP );
[9d6e1b8a]	459	/* paranoid */ verify( thrd_dst->curr_cluster == this->cltr );
[8fc652e0]	460	/* paranoid */ verify( kernelTLS().this_thread == thrd_dst );
	461	/* paranoid */ verify( ! __preemption_enabled() );
[75f3522]	462
[58d64a4]	463	// Reset global state
[8fc652e0]	464	kernelTLS().this_thread = 0p;
[3381ed7]	465
	466	// We just finished running a thread, there are a few things that could have happened.
	467	// 1 - Regular case : the thread has blocked and now one has scheduled it yet.
	468	// 2 - Racy case : the thread has blocked but someone has already tried to schedule it.
	469	// 4 - Preempted
	470	// In case 1, we may have won a race so we can't write to the state again.
	471	// In case 2, we lost the race so we now own the thread.
	472
	473	if(unlikely(thrd_dst->preempted != __NO_PREEMPTION)) {
	474	// The thread was preempted, reschedule it and reset the flag
[254ad1b]	475	schedule_thread$( thrd_dst );
[3381ed7]	476	break RUNNING;
	477	}
[75f3522]	478
[3ea8ad1]	479	if(unlikely(thrd_dst->state == Halting)) {
[ff79d5e]	480	// The thread has halted, it should never be scheduled/run again
[5afb49a]	481	// finish the thread
	482	__thread_finish( thrd_dst );
[ff79d5e]	483	break RUNNING;
	484	}
	485
	486	/* paranoid */ verify( thrd_dst->state == Active );
	487	thrd_dst->state = Blocked;
	488
[3381ed7]	489	// set state of processor coroutine to active and the thread to inactive
[ff79d5e]	490	int old_ticket = __atomic_fetch_sub(&thrd_dst->ticket, 1, __ATOMIC_SEQ_CST);
	491	switch(old_ticket) {
[6a77224]	492	case TICKET_RUNNING:
[3381ed7]	493	// This is case 1, the regular case, nothing more is needed
	494	break RUNNING;
[6a77224]	495	case TICKET_UNBLOCK:
[ec43cf9]	496	#if !defined(__CFA_NO_STATISTICS__)
	497	__tls_stats()->ready.threads.threads++;
	498	#endif
[3381ed7]	499	// This is case 2, the racy case, someone tried to run this thread before it finished blocking
	500	// In this case, just run it again.
	501	continue RUNNING;
	502	default:
	503	// This makes no sense, something is wrong abort
[ff79d5e]	504	abort();
[3381ed7]	505	}
[9f575ea]	506	}
[e8e457e]	507
[9f575ea]	508	// Just before returning to the processor, set the processor coroutine to active
[e8e457e]	509	proc_cor->state = Active;
[1eb239e4]	510
[dddb3dd0]	511	__cfadbg_print_safe(runtime_core, "Kernel : core %p finished running thread %p\n", this, thrd_dst);
	512
[ec43cf9]	513	#if !defined(__CFA_NO_STATISTICS__)
	514	__tls_stats()->ready.threads.threads--;
	515	#endif
	516
[8fc652e0]	517	/* paranoid */ verify( ! __preemption_enabled() );
[82c948c]	518	}
	519
[14a61b5]	520	// KERNEL_ONLY
[b0c7419]	521	void returnToKernel() {
[8fc652e0]	522	/* paranoid */ verify( ! __preemption_enabled() );
[e84ab3d]	523	coroutine$ * proc_cor = get_coroutine(kernelTLS().this_processor->runner);
	524	thread$ * thrd_src = kernelTLS().this_thread;
[e8e457e]	525
[89eff25]	526	__STATS( thrd_src->last_proc = kernelTLS().this_processor; )
[29cb302]	527
[9f575ea]	528	// Run the thread on this processor
	529	{
	530	int local_errno = *__volatile_errno();
	531	#if defined( __i386 ) \|\| defined( __x86_64 )
	532	__x87_store;
	533	#endif
[b4b63e8]	534	/* paranoid */ verify( proc_cor->context.SP );
[ac12f1f]	535	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_src->canary );
[c7a900a]	536	__cfactx_switch( &thrd_src->context, &proc_cor->context );
[ac12f1f]	537	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_src->canary );
[9f575ea]	538	#if defined( __i386 ) \|\| defined( __x86_64 )
	539	__x87_load;
	540	#endif
	541	*__volatile_errno() = local_errno;
[8fcbb4c]	542	}
[deca0f5]	543
[29cb302]	544	#if !defined(__CFA_NO_STATISTICS__)
[89eff25]	545	/* paranoid */ verify( thrd_src->last_proc != 0p );
	546	if(thrd_src->last_proc != kernelTLS().this_processor) {
[29cb302]	547	__tls_stats()->ready.threads.migration++;
	548	}
	549	#endif
	550
[8fc652e0]	551	/* paranoid */ verify( ! __preemption_enabled() );
[e84ab3d]	552	/* paranoid */ verifyf( ((uintptr_t)thrd_src->context.SP) < ((uintptr_t)__get_stack(thrd_src->curr_cor)->base ) \|\| thrd_src->corctx_flag, "ERROR : Returning thread$ %p has been corrupted.\n StackPointer too small.\n", thrd_src );
	553	/* paranoid */ verifyf( ((uintptr_t)thrd_src->context.SP) > ((uintptr_t)__get_stack(thrd_src->curr_cor)->limit) \|\| thrd_src->corctx_flag, "ERROR : Returning thread$ %p has been corrupted.\n StackPointer too large.\n", thrd_src );
[c84e80a]	554	}
	555
[8def349]	556	//-----------------------------------------------------------------------------
	557	// Scheduler routines
[14a61b5]	558	// KERNEL ONLY
[e84ab3d]	559	static void __schedule_thread( thread$ * thrd ) {
[8fc652e0]	560	/* paranoid */ verify( ! __preemption_enabled() );
[254ad1b]	561	/* paranoid */ verify( ready_schedule_islocked());
[6a490b2]	562	/* paranoid */ verify( thrd );
	563	/* paranoid */ verify( thrd->state != Halted );
[9d6e1b8a]	564	/* paranoid */ verify( thrd->curr_cluster );
[3381ed7]	565	/* paranoid */ #if defined( __CFA_WITH_VERIFY__ )
[504a7dc]	566	/* paranoid */ if( thrd->state == Blocked \|\| thrd->state == Start ) assertf( thrd->preempted == __NO_PREEMPTION,
	567	"Error inactive thread marked as preempted, state %d, preemption %d\n", thrd->state, thrd->preempted );
[ff79d5e]	568	/* paranoid */ if( thrd->preempted != __NO_PREEMPTION ) assertf(thrd->state == Active,
[504a7dc]	569	"Error preempted thread marked as not currently running, state %d, preemption %d\n", thrd->state, thrd->preempted );
[3381ed7]	570	/* paranoid */ #endif
[6a490b2]	571	/* paranoid */ verifyf( thrd->link.next == 0p, "Expected null got %p", thrd->link.next );
[ac12f1f]	572	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd->canary );
[b4b63e8]	573
[b808625]	574	const bool local = thrd->state != Start;
[ae7be7a]	575	if (thrd->preempted == __NO_PREEMPTION) thrd->state = Ready;
[6b4cdd3]	576
[ec43cf9]	577	// Dereference the thread now because once we push it, there is not guaranteed it's still valid.
	578	struct cluster * cl = thrd->curr_cluster;
[89eff25]	579	__STATS(bool outside = thrd->last_proc && thrd->last_proc != kernelTLS().this_processor; )
[32a8b61]	580
[254ad1b]	581	// push the thread to the cluster ready-queue
[b808625]	582	push( cl, thrd, local );
[32a8b61]	583
[254ad1b]	584	// variable thrd is no longer safe to use
[734908c]	585	thrd = 0xdeaddeaddeaddeadp;
[32a8b61]	586
[254ad1b]	587	// wake the cluster using the save variable.
	588	__wake_one( cl );
[1c273d0]	589
[ec43cf9]	590	#if !defined(__CFA_NO_STATISTICS__)
	591	if( kernelTLS().this_stats ) {
	592	__tls_stats()->ready.threads.threads++;
[89eff25]	593	if(outside) {
	594	__tls_stats()->ready.threads.extunpark++;
	595	}
[ec43cf9]	596	}
	597	else {
	598	__atomic_fetch_add(&cl->stats->ready.threads.threads, 1, __ATOMIC_RELAXED);
[89eff25]	599	__atomic_fetch_add(&cl->stats->ready.threads.extunpark, 1, __ATOMIC_RELAXED);
[ec43cf9]	600	}
	601	#endif
	602
[254ad1b]	603	/* paranoid */ verify( ready_schedule_islocked());
[8fc652e0]	604	/* paranoid */ verify( ! __preemption_enabled() );
[db6f06a]	605	}
	606
[e84ab3d]	607	void schedule_thread$( thread$ * thrd ) {
[254ad1b]	608	ready_schedule_lock();
	609	__schedule_thread( thrd );
	610	ready_schedule_unlock();
	611	}
	612
[14a61b5]	613	// KERNEL ONLY
[e84ab3d]	614	static inline thread$ * __next_thread(cluster * this) with( *this ) {
[8fc652e0]	615	/* paranoid */ verify( ! __preemption_enabled() );
[7768b8d]	616
[e873838]	617	ready_schedule_lock();
[e84ab3d]	618	thread$ * thrd = pop_fast( this );
[e873838]	619	ready_schedule_unlock();
[7768b8d]	620
[8fc652e0]	621	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	622	return thrd;
[eb2e723]	623	}
	624
[64a7146]	625	// KERNEL ONLY
[e84ab3d]	626	static inline thread$ * __next_thread_slow(cluster * this) with( *this ) {
[8fc652e0]	627	/* paranoid */ verify( ! __preemption_enabled() );
[64a7146]	628
[e873838]	629	ready_schedule_lock();
[e84ab3d]	630	thread$ * thrd;
[fc59df78]	631	for(25) {
	632	thrd = pop_slow( this );
	633	if(thrd) goto RET;
	634	}
	635	thrd = pop_search( this );
	636
	637	RET:
[e873838]	638	ready_schedule_unlock();
[64a7146]	639
[8fc652e0]	640	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	641	return thrd;
[64a7146]	642	}
	643
[e84ab3d]	644	static inline bool __must_unpark( thread$ * thrd ) {
[ff79d5e]	645	int old_ticket = __atomic_fetch_add(&thrd->ticket, 1, __ATOMIC_SEQ_CST);
	646	switch(old_ticket) {
[6a77224]	647	case TICKET_RUNNING:
[3381ed7]	648	// Wake won the race, the thread will reschedule/rerun itself
[c6c7e6c]	649	return false;
[6a77224]	650	case TICKET_BLOCKED:
[3381ed7]	651	/* paranoid */ verify( ! thrd->preempted != __NO_PREEMPTION );
[ff79d5e]	652	/* paranoid */ verify( thrd->state == Blocked );
[c6c7e6c]	653	return true;
[3381ed7]	654	default:
	655	// This makes no sense, something is wrong abort
[7ee8153]	656	abort("Thread %p (%s) has mismatch park/unpark\n", thrd, thrd->self_cor.name);
[de6319f]	657	}
[eb2e723]	658	}
	659
[e84ab3d]	660	void __kernel_unpark( thread$ * thrd ) {
[e9c0b4c]	661	/* paranoid */ verify( ! __preemption_enabled() );
	662	/* paranoid */ verify( ready_schedule_islocked());
	663
	664	if( !thrd ) return;
	665
	666	if(__must_unpark(thrd)) {
	667	// Wake lost the race,
	668	__schedule_thread( thrd );
	669	}
	670
	671	/* paranoid */ verify( ready_schedule_islocked());
	672	/* paranoid */ verify( ! __preemption_enabled() );
	673	}
	674
[e84ab3d]	675	void unpark( thread$ * thrd ) {
[c6c7e6c]	676	if( !thrd ) return;
[0b33412]	677
[c6c7e6c]	678	if(__must_unpark(thrd)) {
	679	disable_interrupts();
[a3821fa]	680	// Wake lost the race,
[254ad1b]	681	schedule_thread$( thrd );
[a3821fa]	682	enable_interrupts(false);
[de6319f]	683	}
[eb2e723]	684	}
[0b33412]	685
[e235429]	686	void park( void ) {
[a3821fa]	687	__disable_interrupts_checked();
	688	/* paranoid */ verify( kernelTLS().this_thread->preempted == __NO_PREEMPTION );
	689	returnToKernel();
	690	__enable_interrupts_checked();
[0c78741]	691
	692	}
[09800e9]	693
[5afb49a]	694	extern "C" {
	695	// Leave the thread monitor
	696	// last routine called by a thread.
	697	// Should never return
	698	void __cfactx_thrd_leave() {
[e84ab3d]	699	thread$ * thrd = active_thread();
	700	monitor$ * this = &thrd->self_mon;
[5afb49a]	701
	702	// Lock the monitor now
	703	lock( this->lock __cfaabi_dbg_ctx2 );
	704
	705	disable_interrupts();
	706
[9d6e1b8a]	707	/* paranoid */ verify( ! __preemption_enabled() );
	708	/* paranoid */ verify( thrd->state == Active );
	709	/* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd->canary );
	710	/* paranoid */ verify( kernelTLS().this_thread == thrd );
	711	/* paranoid */ verify( thrd->context.SP );
[e84ab3d]	712	/* 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 );
	713	/* 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 );
[9d6e1b8a]	714
[3ea8ad1]	715	thrd->state = Halting;
[58688bf]	716	if( TICKET_RUNNING != thrd->ticket ) { abort( "Thread terminated with pending unpark" ); }
[9d6e1b8a]	717	if( thrd != this->owner ) { abort( "Thread internal monitor has incorrect owner" ); }
	718	if( this->recursion != 1) { abort( "Thread internal monitor has unbalanced recursion" ); }
[5afb49a]	719
	720	// Leave the thread
	721	returnToKernel();
	722
	723	// Control flow should never reach here!
[9d6e1b8a]	724	abort();
[5afb49a]	725	}
[09800e9]	726	}
	727
[14a61b5]	728	// KERNEL ONLY
[3381ed7]	729	bool force_yield( __Preemption_Reason reason ) {
[a3821fa]	730	__disable_interrupts_checked();
[e84ab3d]	731	thread$ * thrd = kernelTLS().this_thread;
[a3821fa]	732	/* paranoid */ verify(thrd->state == Active);
	733
	734	// SKULLDUGGERY: It is possible that we are preempting this thread just before
	735	// it was going to park itself. If that is the case and it is already using the
	736	// intrusive fields then we can't use them to preempt the thread
	737	// If that is the case, abandon the preemption.
	738	bool preempted = false;
	739	if(thrd->link.next == 0p) {
	740	preempted = true;
	741	thrd->preempted = reason;
	742	returnToKernel();
	743	}
	744	__enable_interrupts_checked( false );
[3381ed7]	745	return preempted;
[f2b12406]	746	}
	747
[14a61b5]	748	//=============================================================================================
[92e7631]	749	// Kernel Idle Sleep
[14a61b5]	750	//=============================================================================================
[64a7146]	751	// Wake a thread from the front if there are any
[e873838]	752	static void __wake_one(cluster * this) {
[8fc652e0]	753	/* paranoid */ verify( ! __preemption_enabled() );
[e873838]	754	/* paranoid */ verify( ready_schedule_islocked() );
[14a61b5]	755
[64a7146]	756	// Check if there is a sleeping processor
[1eb239e4]	757	processor * p;
	758	unsigned idle;
	759	unsigned total;
[6a9b12b]	760	[idle, total, p] = query_idles(this->procs);
[14a61b5]	761
[64a7146]	762	// If no one is sleeping, we are done
[1eb239e4]	763	if( idle == 0 ) return;
[14a61b5]	764
[64a7146]	765	// We found a processor, wake it up
[dddb3dd0]	766	eventfd_t val;
	767	val = 1;
	768	eventfd_write( p->idle, val );
[14a61b5]	769
[1eb239e4]	770	#if !defined(__CFA_NO_STATISTICS__)
[5cb51502]	771	if( kernelTLS().this_stats ) {
	772	__tls_stats()->ready.sleep.wakes++;
	773	}
	774	else {
	775	__atomic_fetch_add(&this->stats->ready.sleep.wakes, 1, __ATOMIC_RELAXED);
	776	}
[1eb239e4]	777	#endif
	778
[e873838]	779	/* paranoid */ verify( ready_schedule_islocked() );
[8fc652e0]	780	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	781
	782	return;
[64a7146]	783	}
[14a61b5]	784
[64a7146]	785	// Unconditionnaly wake a thread
[1eb239e4]	786	void __wake_proc(processor * this) {
[64a7146]	787	__cfadbg_print_safe(runtime_core, "Kernel : waking Processor %p\n", this);
[14a61b5]	788
[a3821fa]	789	__disable_interrupts_checked();
[8fc652e0]	790	/* paranoid */ verify( ! __preemption_enabled() );
[dddb3dd0]	791	eventfd_t val;
	792	val = 1;
[55d6affb]	793	eventfd_write( this->idle, val );
[a3821fa]	794	__enable_interrupts_checked();
[92e7631]	795	}
	796
[6a9b12b]	797	static void mark_idle(__cluster_proc_list & this, processor & proc) {
[8fc652e0]	798	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	799	lock( this );
	800	this.idle++;
	801	/* paranoid */ verify( this.idle <= this.total );
[fc59b580]	802	remove(proc);
[6a9b12b]	803	insert_first(this.idles, proc);
[1eb239e4]	804	unlock( this );
[8fc652e0]	805	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	806	}
[8e16177]	807
[6a9b12b]	808	static void mark_awake(__cluster_proc_list & this, processor & proc) {
[8fc652e0]	809	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	810	lock( this );
	811	this.idle--;
	812	/* paranoid */ verify( this.idle >= 0 );
	813	remove(proc);
[fc59b580]	814	insert_last(this.actives, proc);
[1eb239e4]	815	unlock( this );
[8fc652e0]	816	/* paranoid */ verify( ! __preemption_enabled() );
[1eb239e4]	817	}
[c34ebf2]	818
[6a9b12b]	819	static [unsigned idle, unsigned total, * processor] query_idles( & __cluster_proc_list this ) {
	820	/* paranoid */ verify( ! __preemption_enabled() );
	821	/* paranoid */ verify( ready_schedule_islocked() );
	822
[1eb239e4]	823	for() {
	824	uint64_t l = __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST);
	825	if( 1 == (l % 2) ) { Pause(); continue; }
	826	unsigned idle = this.idle;
	827	unsigned total = this.total;
[6a9b12b]	828	processor * proc = &this.idles`first;
[7fdae38]	829	// Compiler fence is unnecessary, but gcc-8 and older incorrectly reorder code without it
	830	asm volatile("": : :"memory");
[1eb239e4]	831	if(l != __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST)) { Pause(); continue; }
	832	return [idle, total, proc];
	833	}
[6a9b12b]	834
	835	/* paranoid */ verify( ready_schedule_islocked() );
	836	/* paranoid */ verify( ! __preemption_enabled() );
[6b4cdd3]	837	}
	838
[dbe9b08]	839	//=============================================================================================
	840	// Unexpected Terminating logic
	841	//=============================================================================================
[92bfda0]	842	void __kernel_abort_msg( char * abort_text, int abort_text_size ) {
[e84ab3d]	843	thread$ * thrd = __cfaabi_tls.this_thread;
[9d944b2]	844
[de94a60]	845	if(thrd) {
	846	int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
[1c40091]	847	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[de94a60]	848
[212c2187]	849	if ( &thrd->self_cor != thrd->curr_cor ) {
	850	len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
[1c40091]	851	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[de94a60]	852	}
	853	else {
[1c40091]	854	__cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
[de94a60]	855	}
[1c273d0]	856	}
[9d944b2]	857	else {
[de94a60]	858	int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
[1c40091]	859	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[9d944b2]	860	}
	861	}
	862
[92bfda0]	863	int __kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
	864	return get_coroutine(__cfaabi_tls.this_thread) == get_coroutine(mainThread) ? 4 : 2;
[2b8bc41]	865	}
	866
[de94a60]	867	static __spinlock_t kernel_debug_lock;
	868
[9d944b2]	869	extern "C" {
[1c40091]	870	void __cfaabi_bits_acquire() {
[36982fc]	871	lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
[9d944b2]	872	}
	873
[1c40091]	874	void __cfaabi_bits_release() {
[ea7d2b0]	875	unlock( kernel_debug_lock );
[9d944b2]	876	}
[8118303]	877	}
	878
[fa21ac9]	879	//=============================================================================================
	880	// Kernel Utilities
	881	//=============================================================================================
[dddb3dd0]	882	#if defined(CFA_HAVE_LINUX_IO_URING_H)
	883	#include "io/types.hfa"
	884	#endif
	885
[c1c95b1]	886	static inline bool __maybe_io_drain( processor * proc ) {
[e9c0b4c]	887	bool ret = false;
[dddb3dd0]	888	#if defined(CFA_HAVE_LINUX_IO_URING_H)
	889	__cfadbg_print_safe(runtime_core, "Kernel : core %p checking io for ring %d\n", proc, proc->io.ctx->fd);
	890
	891	// Check if we should drain the queue
	892	$io_context * ctx = proc->io.ctx;
	893	unsigned head = *ctx->cq.head;
	894	unsigned tail = *ctx->cq.tail;
[c1c95b1]	895	if(head == tail) return false;
[57f70ab]	896	#if OLD_MAIN
[b7fd2db6]	897	ready_schedule_lock();
[e9c0b4c]	898	ret = __cfa_io_drain( proc );
[b7fd2db6]	899	ready_schedule_unlock();
[57f70ab]	900	#else
	901	ret = __cfa_io_drain( proc );
	902	#endif
[dddb3dd0]	903	#endif
[e9c0b4c]	904	return ret;
[dddb3dd0]	905	}
	906
[de94a60]	907	//-----------------------------------------------------------------------------
	908	// Debug
	909	__cfaabi_dbg_debug_do(
[1997b4e]	910	extern "C" {
[ae66348]	911	void __cfaabi_dbg_record_lock(__spinlock_t & this, const char prev_name[]) {
[1997b4e]	912	this.prev_name = prev_name;
[8fc652e0]	913	this.prev_thrd = kernelTLS().this_thread;
[1997b4e]	914	}
[9181f1d]	915	}
[f7d6bb0]	916	)
[2026bb6]	917
	918	//-----------------------------------------------------------------------------
	919	// Debug
[8c50aed]	920	bool threading_enabled(void) __attribute__((const)) {
[2026bb6]	921	return true;
	922	}
[c34ebf2]	923
	924	//-----------------------------------------------------------------------------
	925	// Statistics
	926	#if !defined(__CFA_NO_STATISTICS__)
	927	void print_halts( processor & this ) {
	928	this.print_halts = true;
	929	}
[58688bf]	930
[69914cbc]	931	static void crawl_list( cluster * cltr, dlist(processor) & list, unsigned count ) {
[8464edf]	932	/* paranoid */ verify( cltr->stats );
	933
	934	processor * it = &list`first;
	935	for(unsigned i = 0; i < count; i++) {
	936	/* paranoid */ verifyf( it, "Unexpected null iterator, at index %u of %u\n", i, count);
	937	/* paranoid */ verify( it->local_data->this_stats );
	938	__tally_stats( cltr->stats, it->local_data->this_stats );
	939	it = &(*it)`next;
	940	}
	941	}
	942
	943	void crawl_cluster_stats( cluster & this ) {
	944	// Stop the world, otherwise stats could get really messed-up
	945	// this doesn't solve all problems but does solve many
	946	// so it's probably good enough
	947	uint_fast32_t last_size = ready_mutate_lock();
	948
	949	crawl_list(&this, this.procs.actives, this.procs.total - this.procs.idle);
	950	crawl_list(&this, this.procs.idles , this.procs.idle );
	951
	952	// Unlock the RWlock
	953	ready_mutate_unlock( last_size );
	954	}
	955
	956
[58688bf]	957	void print_stats_now( cluster & this, int flags ) {
[8464edf]	958	crawl_cluster_stats( this );
[1b033b8]	959	__print_stats( this.stats, this.print_stats, "Cluster", this.name, (void*)&this );
	960	}
[c34ebf2]	961	#endif
[8118303]	962	// Local Variables: //
	963	// mode: c //
	964	// tab-width: 4 //
	965	// End: //

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