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Last change on this file since 8e27ac45 was c34ebf2, checked in by Thierry Delisle <tdelisle@…>, 5 years ago
Processors now have their own print stats flag
Property mode set to `100644`
File size: 38.1 KB

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1	//
2	// Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo
3	//
4	// The contents of this file are covered under the licence agreement in the
5	// file "LICENCE" distributed with Cforall.
6	//
7	// kernel.c --
8	//
9	// Author : Thierry Delisle
10	// Created On : Tue Jan 17 12:27:26 2017
11	// Last Modified By : Peter A. Buhr
12	// Last Modified On : Tue May 26 22:05:19 2020
13	// Update Count : 59
14	//
15
16	#define __cforall_thread__
17	// #define __CFA_DEBUG_PRINT_RUNTIME_CORE__
18
19	//C Includes
20	#include <stddef.h>
21	#include <errno.h>
22	#include <string.h>
23	#include <stdio.h>
24	#include <fenv.h>
25	#include <signal.h>
26	#include <unistd.h>
27	#include <limits.h> // PTHREAD_STACK_MIN
28	#include <sys/mman.h> // mprotect
29	extern "C" {
30	#include <sys/resource.h>
31	}
32
33	//CFA Includes
34	#include "time.hfa"
35	#include "kernel_private.hfa"
36	#include "preemption.hfa"
37	#include "startup.hfa"
38
39	//Private includes
40	#define __CFA_INVOKE_PRIVATE__
41	#include "invoke.h"
42
43
44	//-----------------------------------------------------------------------------
45	// Some assembly required
46	#if defined( __i386 )
47	#define CtxGet( ctx ) \
48	__asm__ volatile ( \
49	"movl %%esp,%0\n"\
50	"movl %%ebp,%1\n"\
51	: "=rm" (ctx.SP),\
52	"=rm" (ctx.FP) \
53	)
54
55	// mxcr : SSE Status and Control bits (control bits are preserved across function calls)
56	// fcw : X87 FPU control word (preserved across function calls)
57	#define __x87_store \
58	uint32_t __mxcr; \
59	uint16_t __fcw; \
60	__asm__ volatile ( \
61	"stmxcsr %0\n" \
62	"fnstcw %1\n" \
63	: "=m" (__mxcr),\
64	"=m" (__fcw) \
65	)
66
67	#define __x87_load \
68	__asm__ volatile ( \
69	"fldcw %1\n" \
70	"ldmxcsr %0\n" \
71	::"m" (__mxcr),\
72	"m" (__fcw) \
73	)
74
75	#elif defined( __x86_64 )
76	#define CtxGet( ctx ) \
77	__asm__ volatile ( \
78	"movq %%rsp,%0\n"\
79	"movq %%rbp,%1\n"\
80	: "=rm" (ctx.SP),\
81	"=rm" (ctx.FP) \
82	)
83
84	#define __x87_store \
85	uint32_t __mxcr; \
86	uint16_t __fcw; \
87	__asm__ volatile ( \
88	"stmxcsr %0\n" \
89	"fnstcw %1\n" \
90	: "=m" (__mxcr),\
91	"=m" (__fcw) \
92	)
93
94	#define __x87_load \
95	__asm__ volatile ( \
96	"fldcw %1\n" \
97	"ldmxcsr %0\n" \
98	:: "m" (__mxcr),\
99	"m" (__fcw) \
100	)
101
102
103	#elif defined( __ARM_ARCH )
104	#define CtxGet( ctx ) __asm__ ( \
105	"mov %0,%%sp\n" \
106	"mov %1,%%r11\n" \
107	: "=rm" (ctx.SP), "=rm" (ctx.FP) )
108	#else
109	#error unknown hardware architecture
110	#endif
111
112	//-----------------------------------------------------------------------------
113	//Start and stop routine for the kernel, declared first to make sure they run first
114	static void __kernel_startup (void) __attribute__(( constructor( STARTUP_PRIORITY_KERNEL ) ));
115	static void __kernel_shutdown(void) __attribute__(( destructor ( STARTUP_PRIORITY_KERNEL ) ));
116
117	//-----------------------------------------------------------------------------
118	// Kernel Scheduling logic
119	static $thread * __next_thread(cluster * this);
120	static bool __has_next_thread(cluster * this);
121	static void __run_thread(processor * this, $thread * dst);
122	static bool __wake_proc(processor *);
123	static bool __wake_one(struct __processor_id_t * id, cluster * cltr);
124	static void __halt(processor * this);
125
126	//-----------------------------------------------------------------------------
127	// Kernel storage
128	KERNEL_STORAGE(cluster, mainCluster);
129	KERNEL_STORAGE(processor, mainProcessor);
130	KERNEL_STORAGE($thread, mainThread);
131	KERNEL_STORAGE(__stack_t, mainThreadCtx);
132	KERNEL_STORAGE(__scheduler_RWLock_t, __scheduler_lock);
133	#if !defined(__CFA_NO_STATISTICS__)
134	KERNEL_STORAGE(__stats_t, mainProcStats);
135	#endif
136
137	cluster * mainCluster;
138	processor * mainProcessor;
139	$thread * mainThread;
140	__scheduler_RWLock_t * __scheduler_lock;
141
142	extern "C" {
143	struct { __dllist_t(cluster) list; __spinlock_t lock; } __cfa_dbg_global_clusters;
144	}
145
146	size_t __page_size = 0;
147
148	//-----------------------------------------------------------------------------
149	// Global state
150	thread_local struct KernelThreadData kernelTLS __attribute__ ((tls_model ( "initial-exec" ))) = {
151	NULL, // cannot use 0p
152	NULL,
153	NULL,
154	{ 1, false, false },
155	6u //this should be seeded better but due to a bug calling rdtsc doesn't work
156	};
157
158	//-----------------------------------------------------------------------------
159	// Struct to steal stack
160	struct current_stack_info_t {
161	__stack_t * storage; // pointer to stack object
162	void * base; // base of stack
163	void * limit; // stack grows towards stack limit
164	void * context; // address of cfa_context_t
165	};
166
167	void ?{}( current_stack_info_t & this ) {
168	__stack_context_t ctx;
169	CtxGet( ctx );
170	this.base = ctx.FP;
171
172	rlimit r;
173	getrlimit( RLIMIT_STACK, &r);
174	size_t size = r.rlim_cur;
175
176	this.limit = (void *)(((intptr_t)this.base) - size);
177	this.context = &storage_mainThreadCtx;
178	}
179
180	//-----------------------------------------------------------------------------
181	// Main thread construction
182
183	void ?{}( $coroutine & this, current_stack_info_t * info) with( this ) {
184	stack.storage = info->storage;
185	with(*stack.storage) {
186	limit = info->limit;
187	base = info->base;
188	}
189	__attribute__((may_alias)) intptr_t * istorage = (intptr_t*) &stack.storage;
190	*istorage \|= 0x1;
191	name = "Main Thread";
192	state = Start;
193	starter = 0p;
194	last = 0p;
195	cancellation = 0p;
196	}
197
198	void ?{}( $thread & this, current_stack_info_t * info) with( this ) {
199	ticket = 1;
200	state = Start;
201	self_cor{ info };
202	curr_cor = &self_cor;
203	curr_cluster = mainCluster;
204	self_mon.owner = &this;
205	self_mon.recursion = 1;
206	self_mon_p = &self_mon;
207	link.next = 0p;
208	link.prev = 0p;
209
210	node.next = 0p;
211	node.prev = 0p;
212	doregister(curr_cluster, this);
213
214	monitors{ &self_mon_p, 1, (fptr_t)0 };
215	}
216
217	//-----------------------------------------------------------------------------
218	// Processor coroutine
219	void ?{}(processorCtx_t & this) {
220
221	}
222
223	// Construct the processor context of non-main processors
224	static void ?{}(processorCtx_t & this, processor * proc, current_stack_info_t * info) {
225	(this.__cor){ info };
226	this.proc = proc;
227	}
228
229	static void * __invoke_processor(void * arg);
230
231	void ?{}(processor & this, const char name[], cluster & _cltr) with( this ) {
232	this.name = name;
233	this.cltr = &_cltr;
234	id = -1u;
235	terminated{ 0 };
236	destroyer = 0p;
237	do_terminate = false;
238	preemption_alarm = 0p;
239	pending_preemption = false;
240	runner.proc = &this;
241
242	#if !defined(__CFA_NO_STATISTICS__)
243	print_stats = false;
244	print_halts = false;
245	#endif
246
247	idle{};
248
249	__cfadbg_print_safe(runtime_core, "Kernel : Starting core %p\n", &this);
250
251	this.stack = __create_pthread( &this.kernel_thread, __invoke_processor, (void *)&this );
252	__atomic_fetch_add( &cltr->nprocessors, 1u, __ATOMIC_SEQ_CST );
253
254	__cfadbg_print_safe(runtime_core, "Kernel : core %p created\n", &this);
255	}
256
257	void ^?{}(processor & this) with( this ){
258	if( ! __atomic_load_n(&do_terminate, __ATOMIC_ACQUIRE) ) {
259	__cfadbg_print_safe(runtime_core, "Kernel : core %p signaling termination\n", &this);
260
261	__atomic_store_n(&do_terminate, true, __ATOMIC_RELAXED);
262	__wake_proc( &this );
263
264	P( terminated );
265	verify( kernelTLS.this_processor != &this);
266	}
267
268	int err = pthread_join( kernel_thread, 0p );
269	if( err != 0 ) abort("KERNEL ERROR: joining processor %p caused error %s\n", &this, strerror(err));
270
271	free( this.stack );
272
273	__atomic_fetch_sub( &cltr->nprocessors, 1u, __ATOMIC_SEQ_CST );
274	}
275
276	void ?{}(cluster & this, const char name[], Duration preemption_rate, unsigned io_flags) with( this ) {
277	this.name = name;
278	this.preemption_rate = preemption_rate;
279	this.nprocessors = 0;
280	ready_queue{};
281
282	#if !defined(__CFA_NO_STATISTICS__)
283	print_stats = false;
284	stats = alloc();
285	__init_stats( stats );
286	#endif
287
288	threads{ __get };
289
290	__kernel_io_startup( this, io_flags, &this == mainCluster );
291
292	doregister(this);
293	}
294
295	void ^?{}(cluster & this) {
296	__kernel_io_shutdown( this, &this == mainCluster );
297
298	#if !defined(__CFA_NO_STATISTICS__)
299	if(this.print_stats) {
300	__print_stats( this.stats, true, this.name, (void*)&this );
301	}
302	free( this.stats );
303	#endif
304
305	unregister(this);
306	}
307
308	//=============================================================================================
309	// Kernel Scheduling logic
310	//=============================================================================================
311	//Main of the processor contexts
312	void main(processorCtx_t & runner) {
313	// Because of a bug, we couldn't initialized the seed on construction
314	// Do it here
315	kernelTLS.rand_seed ^= rdtscl();
316
317	processor * this = runner.proc;
318	verify(this);
319
320	__cfadbg_print_safe(runtime_core, "Kernel : core %p starting\n", this);
321
322	// register the processor unless it's the main thread which is handled in the boot sequence
323	if(this != mainProcessor) {
324	this->id = doregister((__processor_id_t*)this);
325	// Lock the RWlock so no-one pushes/pops while we are changing the queue
326	uint_fast32_t last_size = ready_mutate_lock();
327
328	// Adjust the ready queue size
329	ready_queue_grow( this->cltr );
330
331	// Unlock the RWlock
332	ready_mutate_unlock( last_size );
333	}
334
335	{
336	// Setup preemption data
337	preemption_scope scope = { this };
338
339	__cfadbg_print_safe(runtime_core, "Kernel : core %p started\n", this);
340
341	$thread * readyThread = 0p;
342	for( unsigned int spin_count = 0; ! __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST); spin_count++ ) {
343	// Try to get the next thread
344	readyThread = __next_thread( this->cltr );
345
346	// Check if we actually found a thread
347	if( readyThread ) {
348	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
349	/* paranoid */ verifyf( readyThread->state == Ready \|\| readyThread->preempted != __NO_PREEMPTION, "state : %d, preempted %d\n", readyThread->state, readyThread->preempted);
350	/* paranoid */ verifyf( readyThread->link.next == 0p, "Expected null got %p", readyThread->link.next );
351	__builtin_prefetch( readyThread->context.SP );
352
353	// We found a thread run it
354	__run_thread(this, readyThread);
355
356	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
357	}
358	else {
359	// Block until a thread is ready
360	__halt(this);
361	}
362	}
363
364	__cfadbg_print_safe(runtime_core, "Kernel : core %p stopping\n", this);
365	}
366
367	V( this->terminated );
368
369	// unregister the processor unless it's the main thread which is handled in the boot sequence
370	if(this != mainProcessor) {
371	// Lock the RWlock so no-one pushes/pops while we are changing the queue
372	uint_fast32_t last_size = ready_mutate_lock();
373
374	// Adjust the ready queue size
375	ready_queue_shrink( this->cltr );
376
377	// Make sure we aren't on the idle queue
378	#if !defined(__CFA_NO_STATISTICS__)
379	bool removed =
380	#endif
381	unsafe_remove( this->cltr->idles, this );
382
383	#if !defined(__CFA_NO_STATISTICS__)
384	if(removed) __tls_stats()->ready.sleep.exits++;
385	#endif
386
387	// Unlock the RWlock
388	ready_mutate_unlock( last_size );
389
390	// Finally we don't need the read_lock any more
391	unregister((__processor_id_t*)this);
392	}
393	else {
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
397	kernelTLS.this_thread = mainThread;
398	}
399
400	__cfadbg_print_safe(runtime_core, "Kernel : core %p terminated\n", this);
401	}
402
403	static int * __volatile_errno() __attribute__((noinline));
404	static int * __volatile_errno() { asm(""); return &errno; }
405
406	// KERNEL ONLY
407	// runThread runs a thread by context switching
408	// from the processor coroutine to the target thread
409	static void __run_thread(processor * this, $thread * thrd_dst) {
410	$coroutine * proc_cor = get_coroutine(this->runner);
411
412	// Update global state
413	kernelTLS.this_thread = thrd_dst;
414
415	// set state of processor coroutine to inactive
416	verify(proc_cor->state == Active);
417	proc_cor->state = Blocked;
418
419	// Actually run the thread
420	RUNNING: while(true) {
421	thrd_dst->preempted = __NO_PREEMPTION;
422	thrd_dst->state = Active;
423
424	__cfaabi_dbg_debug_do(
425	thrd_dst->park_stale = true;
426	thrd_dst->unpark_stale = true;
427	)
428
429	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
430	/* paranoid */ verify( kernelTLS.this_thread == thrd_dst );
431	/* 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
432	/* 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
433
434	// set context switch to the thread that the processor is executing
435	verify( thrd_dst->context.SP );
436	__cfactx_switch( &proc_cor->context, &thrd_dst->context );
437	// when __cfactx_switch returns we are back in the processor coroutine
438
439	/* 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 );
440	/* 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 );
441	/* paranoid */ verify( kernelTLS.this_thread == thrd_dst );
442	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
443
444
445	// We just finished running a thread, there are a few things that could have happened.
446	// 1 - Regular case : the thread has blocked and now one has scheduled it yet.
447	// 2 - Racy case : the thread has blocked but someone has already tried to schedule it.
448	// 4 - Preempted
449	// In case 1, we may have won a race so we can't write to the state again.
450	// In case 2, we lost the race so we now own the thread.
451
452	if(unlikely(thrd_dst->preempted != __NO_PREEMPTION)) {
453	// The thread was preempted, reschedule it and reset the flag
454	__schedule_thread( (__processor_id_t*)this, thrd_dst );
455	break RUNNING;
456	}
457
458	if(unlikely(thrd_dst->state == Halted)) {
459	// The thread has halted, it should never be scheduled/run again
460	// We may need to wake someone up here since
461	unpark( this->destroyer __cfaabi_dbg_ctx2 );
462	this->destroyer = 0p;
463	break RUNNING;
464	}
465
466	/* paranoid */ verify( thrd_dst->state == Active );
467	thrd_dst->state = Blocked;
468
469	// set state of processor coroutine to active and the thread to inactive
470	int old_ticket = __atomic_fetch_sub(&thrd_dst->ticket, 1, __ATOMIC_SEQ_CST);
471	__cfaabi_dbg_debug_do( thrd_dst->park_result = old_ticket; )
472	switch(old_ticket) {
473	case 1:
474	// This is case 1, the regular case, nothing more is needed
475	break RUNNING;
476	case 2:
477	// This is case 2, the racy case, someone tried to run this thread before it finished blocking
478	// In this case, just run it again.
479	continue RUNNING;
480	default:
481	// This makes no sense, something is wrong abort
482	abort();
483	}
484	}
485
486	// Just before returning to the processor, set the processor coroutine to active
487	proc_cor->state = Active;
488	kernelTLS.this_thread = 0p;
489	}
490
491	// KERNEL_ONLY
492	void returnToKernel() {
493	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
494	$coroutine * proc_cor = get_coroutine(kernelTLS.this_processor->runner);
495	$thread * thrd_src = kernelTLS.this_thread;
496
497	#if !defined(__CFA_NO_STATISTICS__)
498	struct processor * last_proc = kernelTLS.this_processor;
499	#endif
500
501	// Run the thread on this processor
502	{
503	int local_errno = *__volatile_errno();
504	#if defined( __i386 ) \|\| defined( __x86_64 )
505	__x87_store;
506	#endif
507	verify( proc_cor->context.SP );
508	__cfactx_switch( &thrd_src->context, &proc_cor->context );
509	#if defined( __i386 ) \|\| defined( __x86_64 )
510	__x87_load;
511	#endif
512	*__volatile_errno() = local_errno;
513	}
514
515	#if !defined(__CFA_NO_STATISTICS__)
516	if(last_proc != kernelTLS.this_processor) {
517	__tls_stats()->ready.threads.migration++;
518	}
519	#endif
520
521	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
522	/* 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 );
523	/* 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 );
524	}
525
526	// KERNEL_ONLY
527	// Context invoker for processors
528	// This is the entry point for processors (kernel threads)
529	// It effectively constructs a coroutine by stealing the pthread stack
530	static void * __invoke_processor(void * arg) {
531	#if !defined( __CFA_NO_STATISTICS__ )
532	__stats_t local_stats;
533	__init_stats( &local_stats );
534	kernelTLS.this_stats = &local_stats;
535	#endif
536
537	processor * proc = (processor *) arg;
538	kernelTLS.this_processor = proc;
539	kernelTLS.this_thread = 0p;
540	kernelTLS.preemption_state.[enabled, disable_count] = [false, 1];
541	// SKULLDUGGERY: We want to create a context for the processor coroutine
542	// which is needed for the 2-step context switch. However, there is no reason
543	// to waste the perfectly valid stack create by pthread.
544	current_stack_info_t info;
545	__stack_t ctx;
546	info.storage = &ctx;
547	(proc->runner){ proc, &info };
548
549	__cfaabi_dbg_print_safe("Coroutine : created stack %p\n", get_coroutine(proc->runner)->stack.storage);
550
551	//Set global state
552	kernelTLS.this_thread = 0p;
553
554	//We now have a proper context from which to schedule threads
555	__cfadbg_print_safe(runtime_core, "Kernel : core %p created (%p, %p)\n", proc, &proc->runner, &ctx);
556
557	// SKULLDUGGERY: Since the coroutine doesn't have its own stack, we can't
558	// resume it to start it like it normally would, it will just context switch
559	// back to here. Instead directly call the main since we already are on the
560	// appropriate stack.
561	get_coroutine(proc->runner)->state = Active;
562	main( proc->runner );
563	get_coroutine(proc->runner)->state = Halted;
564
565	// Main routine of the core returned, the core is now fully terminated
566	__cfadbg_print_safe(runtime_core, "Kernel : core %p main ended (%p)\n", proc, &proc->runner);
567
568	#if !defined(__CFA_NO_STATISTICS__)
569	__tally_stats(proc->cltr->stats, &local_stats);
570	if(proc->print_stats) {
571	__print_stats( &local_stats, true, proc->name, (void*)proc );
572	}
573	#endif
574
575	return 0p;
576	}
577
578	static void Abort( int ret, const char func[] ) {
579	if ( ret ) { // pthread routines return errno values
580	abort( "%s : internal error, error(%d) %s.", func, ret, strerror( ret ) );
581	} // if
582	} // Abort
583
584	void * __create_pthread( pthread_t * pthread, void * (start)(void ), void * arg ) {
585	pthread_attr_t attr;
586
587	Abort( pthread_attr_init( &attr ), "pthread_attr_init" ); // initialize attribute
588
589	size_t stacksize;
590	// default stack size, normally defined by shell limit
591	Abort( pthread_attr_getstacksize( &attr, &stacksize ), "pthread_attr_getstacksize" );
592	assert( stacksize >= PTHREAD_STACK_MIN );
593
594	void * stack;
595	__cfaabi_dbg_debug_do(
596	stack = memalign( __page_size, stacksize + __page_size );
597	// pthread has no mechanism to create the guard page in user supplied stack.
598	if ( mprotect( stack, __page_size, PROT_NONE ) == -1 ) {
599	abort( "mprotect : internal error, mprotect failure, error(%d) %s.", errno, strerror( errno ) );
600	} // if
601	);
602	__cfaabi_dbg_no_debug_do(
603	stack = malloc( stacksize );
604	);
605
606	Abort( pthread_attr_setstack( &attr, stack, stacksize ), "pthread_attr_setstack" );
607
608	Abort( pthread_create( pthread, &attr, start, arg ), "pthread_create" );
609	return stack;
610	}
611
612	// KERNEL_ONLY
613	static void __kernel_first_resume( processor * this ) {
614	$thread * src = mainThread;
615	$coroutine * dst = get_coroutine(this->runner);
616
617	verify( ! kernelTLS.preemption_state.enabled );
618
619	kernelTLS.this_thread->curr_cor = dst;
620	__stack_prepare( &dst->stack, 65000 );
621	__cfactx_start(main, dst, this->runner, __cfactx_invoke_coroutine);
622
623	verify( ! kernelTLS.preemption_state.enabled );
624
625	dst->last = &src->self_cor;
626	dst->starter = dst->starter ? dst->starter : &src->self_cor;
627
628	// make sure the current state is still correct
629	/* paranoid */ verify(src->state == Ready);
630
631	// context switch to specified coroutine
632	verify( dst->context.SP );
633	__cfactx_switch( &src->context, &dst->context );
634	// when __cfactx_switch returns we are back in the src coroutine
635
636	mainThread->curr_cor = &mainThread->self_cor;
637
638	// make sure the current state has been update
639	/* paranoid */ verify(src->state == Active);
640
641	verify( ! kernelTLS.preemption_state.enabled );
642	}
643
644	// KERNEL_ONLY
645	static void __kernel_last_resume( processor * this ) {
646	$coroutine * src = &mainThread->self_cor;
647	$coroutine * dst = get_coroutine(this->runner);
648
649	verify( ! kernelTLS.preemption_state.enabled );
650	verify( dst->starter == src );
651	verify( dst->context.SP );
652
653	// SKULLDUGGERY in debug the processors check that the
654	// stack is still within the limit of the stack limits after running a thread.
655	// that check doesn't make sense if we context switch to the processor using the
656	// coroutine semantics. Since this is a special case, use the current context
657	// info to populate these fields.
658	__cfaabi_dbg_debug_do(
659	__stack_context_t ctx;
660	CtxGet( ctx );
661	mainThread->context.SP = ctx.SP;
662	mainThread->context.FP = ctx.FP;
663	)
664
665	// context switch to the processor
666	__cfactx_switch( &src->context, &dst->context );
667	}
668
669	//-----------------------------------------------------------------------------
670	// Scheduler routines
671	// KERNEL ONLY
672	void __schedule_thread( struct __processor_id_t * id, $thread * thrd ) {
673	/* paranoid */ verify( thrd );
674	/* paranoid */ verify( thrd->state != Halted );
675	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
676	/* paranoid */ #if defined( __CFA_WITH_VERIFY__ )
677	/* paranoid */ if( thrd->state == Blocked \|\| thrd->state == Start ) assertf( thrd->preempted == __NO_PREEMPTION,
678	"Error inactive thread marked as preempted, state %d, preemption %d\n", thrd->state, thrd->preempted );
679	/* paranoid */ if( thrd->preempted != __NO_PREEMPTION ) assertf(thrd->state == Active,
680	"Error preempted thread marked as not currently running, state %d, preemption %d\n", thrd->state, thrd->preempted );
681	/* paranoid */ #endif
682	/* paranoid */ verifyf( thrd->link.next == 0p, "Expected null got %p", thrd->link.next );
683
684	if (thrd->preempted == __NO_PREEMPTION) thrd->state = Ready;
685
686	ready_schedule_lock ( id );
687	push( thrd->curr_cluster, thrd );
688
689	#if !defined(__CFA_NO_STATISTICS__)
690	bool woke =
691	#endif
692	__wake_one(id, thrd->curr_cluster);
693
694	#if !defined(__CFA_NO_STATISTICS__)
695	if(woke) __tls_stats()->ready.sleep.wakes++;
696	#endif
697	ready_schedule_unlock( id );
698
699	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
700	}
701
702	// KERNEL ONLY
703	static $thread * __next_thread(cluster * this) with( *this ) {
704	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
705
706	ready_schedule_lock ( (__processor_id_t*)kernelTLS.this_processor );
707	$thread * head = pop( this );
708	ready_schedule_unlock( (__processor_id_t*)kernelTLS.this_processor );
709
710	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
711	return head;
712	}
713
714	// KERNEL ONLY
715	static bool __has_next_thread(cluster * this) with( *this ) {
716	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
717
718	ready_schedule_lock ( (__processor_id_t*)kernelTLS.this_processor );
719	bool not_empty = query( this );
720	ready_schedule_unlock( (__processor_id_t*)kernelTLS.this_processor );
721
722	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
723	return not_empty;
724	}
725
726	// KERNEL ONLY unpark with out disabling interrupts
727	void __unpark( struct __processor_id_t * id, $thread * thrd __cfaabi_dbg_ctx_param2 ) {
728	// record activity
729	__cfaabi_dbg_debug_do( char * old_caller = thrd->unpark_caller; )
730	__cfaabi_dbg_record_thrd( *thrd, false, caller );
731
732	int old_ticket = __atomic_fetch_add(&thrd->ticket, 1, __ATOMIC_SEQ_CST);
733	__cfaabi_dbg_debug_do( thrd->unpark_result = old_ticket; thrd->unpark_state = thrd->state; )
734	switch(old_ticket) {
735	case 1:
736	// Wake won the race, the thread will reschedule/rerun itself
737	break;
738	case 0:
739	/* paranoid */ verify( ! thrd->preempted != __NO_PREEMPTION );
740	/* paranoid */ verify( thrd->state == Blocked );
741
742	// Wake lost the race,
743	__schedule_thread( id, thrd );
744	break;
745	default:
746	// This makes no sense, something is wrong abort
747	abort();
748	}
749	}
750
751	void unpark( $thread * thrd __cfaabi_dbg_ctx_param2 ) {
752	if( !thrd ) return;
753
754	disable_interrupts();
755	__unpark( (__processor_id_t*)kernelTLS.this_processor, thrd __cfaabi_dbg_ctx_fwd2 );
756	enable_interrupts( __cfaabi_dbg_ctx );
757	}
758
759	void park( __cfaabi_dbg_ctx_param ) {
760	/* paranoid */ verify( kernelTLS.preemption_state.enabled );
761	disable_interrupts();
762	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
763	/* paranoid */ verify( kernelTLS.this_thread->preempted == __NO_PREEMPTION );
764
765	// record activity
766	__cfaabi_dbg_record_thrd( *kernelTLS.this_thread, true, caller );
767
768	returnToKernel();
769
770	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
771	enable_interrupts( __cfaabi_dbg_ctx );
772	/* paranoid */ verify( kernelTLS.preemption_state.enabled );
773
774	}
775
776	// KERNEL ONLY
777	void __leave_thread() {
778	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
779	returnToKernel();
780	abort();
781	}
782
783	// KERNEL ONLY
784	bool force_yield( __Preemption_Reason reason ) {
785	/* paranoid */ verify( kernelTLS.preemption_state.enabled );
786	disable_interrupts();
787	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
788
789	$thread * thrd = kernelTLS.this_thread;
790	/* paranoid */ verify(thrd->state == Active);
791
792	// SKULLDUGGERY: It is possible that we are preempting this thread just before
793	// it was going to park itself. If that is the case and it is already using the
794	// intrusive fields then we can't use them to preempt the thread
795	// If that is the case, abandon the preemption.
796	bool preempted = false;
797	if(thrd->link.next == 0p) {
798	preempted = true;
799	thrd->preempted = reason;
800	returnToKernel();
801	}
802
803	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
804	enable_interrupts_noPoll();
805	/* paranoid */ verify( kernelTLS.preemption_state.enabled );
806
807	return preempted;
808	}
809
810	//=============================================================================================
811	// Kernel Setup logic
812	//=============================================================================================
813	//-----------------------------------------------------------------------------
814	// Kernel boot procedures
815	static void __kernel_startup(void) {
816	verify( ! kernelTLS.preemption_state.enabled );
817	__cfadbg_print_safe(runtime_core, "Kernel : Starting\n");
818
819	__page_size = sysconf( _SC_PAGESIZE );
820
821	__cfa_dbg_global_clusters.list{ __get };
822	__cfa_dbg_global_clusters.lock{};
823
824	// Initialize the global scheduler lock
825	__scheduler_lock = (__scheduler_RWLock_t*)&storage___scheduler_lock;
826	(*__scheduler_lock){};
827
828	// Initialize the main cluster
829	mainCluster = (cluster *)&storage_mainCluster;
830	(*mainCluster){"Main Cluster"};
831
832	__cfadbg_print_safe(runtime_core, "Kernel : Main cluster ready\n");
833
834	// Start by initializing the main thread
835	// SKULLDUGGERY: the mainThread steals the process main thread
836	// which will then be scheduled by the mainProcessor normally
837	mainThread = ($thread *)&storage_mainThread;
838	current_stack_info_t info;
839	info.storage = (__stack_t*)&storage_mainThreadCtx;
840	(*mainThread){ &info };
841
842	__cfadbg_print_safe(runtime_core, "Kernel : Main thread ready\n");
843
844
845
846	// Construct the processor context of the main processor
847	void ?{}(processorCtx_t & this, processor * proc) {
848	(this.__cor){ "Processor" };
849	this.__cor.starter = 0p;
850	this.proc = proc;
851	}
852
853	void ?{}(processor & this) with( this ) {
854	name = "Main Processor";
855	cltr = mainCluster;
856	terminated{ 0 };
857	do_terminate = false;
858	preemption_alarm = 0p;
859	pending_preemption = false;
860	kernel_thread = pthread_self();
861	id = -1u;
862
863	#if !defined(__CFA_NO_STATISTICS__)
864	print_stats = false;
865	print_halts = false;
866	#endif
867
868	runner{ &this };
869	__cfadbg_print_safe(runtime_core, "Kernel : constructed main processor context %p\n", &runner);
870
871	__atomic_fetch_add( &cltr->nprocessors, 1u, __ATOMIC_SEQ_CST );
872	}
873
874	// Initialize the main processor and the main processor ctx
875	// (the coroutine that contains the processing control flow)
876	mainProcessor = (processor *)&storage_mainProcessor;
877	(*mainProcessor){};
878
879	mainProcessor->id = doregister( (__processor_id_t*)mainProcessor);
880
881	//initialize the global state variables
882	kernelTLS.this_processor = mainProcessor;
883	kernelTLS.this_thread = mainThread;
884
885	#if !defined( __CFA_NO_STATISTICS__ )
886	kernelTLS.this_stats = (__stats_t *)& storage_mainProcStats;
887	__init_stats( kernelTLS.this_stats );
888	#endif
889
890	// Enable preemption
891	kernel_start_preemption();
892
893	// Add the main thread to the ready queue
894	// once resume is called on mainProcessor->runner the mainThread needs to be scheduled like any normal thread
895	__schedule_thread((__processor_id_t *)mainProcessor, mainThread);
896
897	// SKULLDUGGERY: Force a context switch to the main processor to set the main thread's context to the current UNIX
898	// context. Hence, the main thread does not begin through __cfactx_invoke_thread, like all other threads. The trick here is that
899	// mainThread is on the ready queue when this call is made.
900	__kernel_first_resume( kernelTLS.this_processor );
901
902
903	// THE SYSTEM IS NOW COMPLETELY RUNNING
904
905
906	// Now that the system is up, finish creating systems that need threading
907	__kernel_io_finish_start( *mainCluster );
908
909
910	__cfadbg_print_safe(runtime_core, "Kernel : Started\n--------------------------------------------------\n\n");
911
912	verify( ! kernelTLS.preemption_state.enabled );
913	enable_interrupts( __cfaabi_dbg_ctx );
914	verify( TL_GET( preemption_state.enabled ) );
915	}
916
917	static void __kernel_shutdown(void) {
918	//Before we start shutting things down, wait for systems that need threading to shutdown
919	__kernel_io_prepare_stop( *mainCluster );
920
921	/* paranoid */ verify( TL_GET( preemption_state.enabled ) );
922	disable_interrupts();
923	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
924
925	__cfadbg_print_safe(runtime_core, "\n--------------------------------------------------\nKernel : Shutting down\n");
926
927	// SKULLDUGGERY: Notify the mainProcessor it needs to terminates.
928	// When its coroutine terminates, it return control to the mainThread
929	// which is currently here
930	__atomic_store_n(&mainProcessor->do_terminate, true, __ATOMIC_RELEASE);
931	__kernel_last_resume( kernelTLS.this_processor );
932	mainThread->self_cor.state = Halted;
933
934	// THE SYSTEM IS NOW COMPLETELY STOPPED
935
936	// Disable preemption
937	kernel_stop_preemption();
938
939	unregister((__processor_id_t*)mainProcessor);
940
941	// Destroy the main processor and its context in reverse order of construction
942	// These were manually constructed so we need manually destroy them
943	void ^?{}(processor & this) with( this ){
944	/* paranoid */ verify( this.do_terminate == true );
945	__atomic_fetch_sub( &cltr->nprocessors, 1u, __ATOMIC_SEQ_CST );
946	__cfaabi_dbg_print_safe("Kernel : destroyed main processor context %p\n", &runner);
947	}
948
949	^(*mainProcessor){};
950
951	// Final step, destroy the main thread since it is no longer needed
952
953	// Since we provided a stack to this taxk it will not destroy anything
954	/* paranoid / verify(mainThread->self_cor.stack.storage == (__stack_t)(((uintptr_t)&storage_mainThreadCtx)\| 0x1));
955	^(*mainThread){};
956
957	^(*mainCluster){};
958
959	^(*__scheduler_lock){};
960
961	^(__cfa_dbg_global_clusters.list){};
962	^(__cfa_dbg_global_clusters.lock){};
963
964	__cfadbg_print_safe(runtime_core, "Kernel : Shutdown complete\n");
965	}
966
967	//=============================================================================================
968	// Kernel Idle Sleep
969	//=============================================================================================
970	// Wake a thread from the front if there are any
971	static bool __wake_one(struct __processor_id_t * id, cluster * this) {
972	/* paranoid */ verify( ready_schedule_islocked( id ) );
973
974	// Check if there is a sleeping processor
975	processor * p = pop(this->idles);
976
977	// If no one is sleeping, we are done
978	if( 0p == p ) return false;
979
980	// We found a processor, wake it up
981	post( p->idle );
982
983	return true;
984	}
985
986	// Unconditionnaly wake a thread
987	static bool __wake_proc(processor * this) {
988	__cfadbg_print_safe(runtime_core, "Kernel : waking Processor %p\n", this);
989
990	disable_interrupts();
991	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
992	bool ret = post( this->idle );
993	enable_interrupts( __cfaabi_dbg_ctx );
994
995	return ret;
996	}
997
998	static void __halt(processor * this) with( *this ) {
999	if( do_terminate ) return;
1000
1001	#if !defined(__CFA_NO_STATISTICS__)
1002	__tls_stats()->ready.sleep.halts++;
1003	#endif
1004	// Push self to queue
1005	push(cltr->idles, *this);
1006
1007	// Makre sure we don't miss a thread
1008	if( __has_next_thread(cltr) ) {
1009	// A thread was posted, make sure a processor is woken up
1010	struct __processor_id_t id = (struct __processor_id_t ) this;
1011	ready_schedule_lock ( id );
1012	__wake_one( id, cltr );
1013	ready_schedule_unlock( id );
1014	#if !defined(__CFA_NO_STATISTICS__)
1015	__tls_stats()->ready.sleep.cancels++;
1016	#endif
1017	}
1018
1019	#if !defined(__CFA_NO_STATISTICS__)
1020	if(this->print_halts) {
1021	printf("%d - %lld 0\n", this->id, rdtscl());
1022	}
1023	#endif
1024
1025	wait( idle );
1026
1027	#if !defined(__CFA_NO_STATISTICS__)
1028	if(this->print_halts) {
1029	printf("%d - %lld 1\n", this->id, rdtscl());
1030	}
1031	#endif
1032	}
1033
1034	//=============================================================================================
1035	// Unexpected Terminating logic
1036	//=============================================================================================
1037	static __spinlock_t kernel_abort_lock;
1038	static bool kernel_abort_called = false;
1039
1040	void * kernel_abort(void) __attribute__ ((__nothrow__)) {
1041	// abort cannot be recursively entered by the same or different processors because all signal handlers return when
1042	// the globalAbort flag is true.
1043	lock( kernel_abort_lock __cfaabi_dbg_ctx2 );
1044
1045	// first task to abort ?
1046	if ( kernel_abort_called ) { // not first task to abort ?
1047	unlock( kernel_abort_lock );
1048
1049	sigset_t mask;
1050	sigemptyset( &mask );
1051	sigaddset( &mask, SIGALRM ); // block SIGALRM signals
1052	sigaddset( &mask, SIGUSR1 ); // block SIGALRM signals
1053	sigsuspend( &mask ); // block the processor to prevent further damage during abort
1054	_exit( EXIT_FAILURE ); // if processor unblocks before it is killed, terminate it
1055	}
1056	else {
1057	kernel_abort_called = true;
1058	unlock( kernel_abort_lock );
1059	}
1060
1061	return kernelTLS.this_thread;
1062	}
1063
1064	void kernel_abort_msg( void * kernel_data, char * abort_text, int abort_text_size ) {
1065	$thread * thrd = kernel_data;
1066
1067	if(thrd) {
1068	int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
1069	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
1070
1071	if ( &thrd->self_cor != thrd->curr_cor ) {
1072	len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
1073	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
1074	}
1075	else {
1076	__cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
1077	}
1078	}
1079	else {
1080	int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
1081	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
1082	}
1083	}
1084
1085	int kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
1086	return get_coroutine(kernelTLS.this_thread) == get_coroutine(mainThread) ? 4 : 2;
1087	}
1088
1089	static __spinlock_t kernel_debug_lock;
1090
1091	extern "C" {
1092	void __cfaabi_bits_acquire() {
1093	lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
1094	}
1095
1096	void __cfaabi_bits_release() {
1097	unlock( kernel_debug_lock );
1098	}
1099	}
1100
1101	//=============================================================================================
1102	// Kernel Utilities
1103	//=============================================================================================
1104	//-----------------------------------------------------------------------------
1105	// Locks
1106	void ?{}( semaphore & this, int count = 1 ) {
1107	(this.lock){};
1108	this.count = count;
1109	(this.waiting){};
1110	}
1111	void ^?{}(semaphore & this) {}
1112
1113	bool P(semaphore & this) with( this ){
1114	lock( lock __cfaabi_dbg_ctx2 );
1115	count -= 1;
1116	if ( count < 0 ) {
1117	// queue current task
1118	append( waiting, kernelTLS.this_thread );
1119
1120	// atomically release spin lock and block
1121	unlock( lock );
1122	park( __cfaabi_dbg_ctx );
1123	return true;
1124	}
1125	else {
1126	unlock( lock );
1127	return false;
1128	}
1129	}
1130
1131	bool V(semaphore & this) with( this ) {
1132	$thread * thrd = 0p;
1133	lock( lock __cfaabi_dbg_ctx2 );
1134	count += 1;
1135	if ( count <= 0 ) {
1136	// remove task at head of waiting list
1137	thrd = pop_head( waiting );
1138	}
1139
1140	unlock( lock );
1141
1142	// make new owner
1143	unpark( thrd __cfaabi_dbg_ctx2 );
1144
1145	return thrd != 0p;
1146	}
1147
1148	bool V(semaphore & this, unsigned diff) with( this ) {
1149	$thread * thrd = 0p;
1150	lock( lock __cfaabi_dbg_ctx2 );
1151	int release = max(-count, (int)diff);
1152	count += diff;
1153	for(release) {
1154	unpark( pop_head( waiting ) __cfaabi_dbg_ctx2 );
1155	}
1156
1157	unlock( lock );
1158
1159	return thrd != 0p;
1160	}
1161
1162	//-----------------------------------------------------------------------------
1163	// Global Queues
1164	void doregister( cluster & cltr ) {
1165	lock ( __cfa_dbg_global_clusters.lock __cfaabi_dbg_ctx2);
1166	push_front( __cfa_dbg_global_clusters.list, cltr );
1167	unlock ( __cfa_dbg_global_clusters.lock );
1168	}
1169
1170	void unregister( cluster & cltr ) {
1171	lock ( __cfa_dbg_global_clusters.lock __cfaabi_dbg_ctx2);
1172	remove( __cfa_dbg_global_clusters.list, cltr );
1173	unlock( __cfa_dbg_global_clusters.lock );
1174	}
1175
1176	void doregister( cluster * cltr, $thread & thrd ) {
1177	lock (cltr->thread_list_lock __cfaabi_dbg_ctx2);
1178	cltr->nthreads += 1;
1179	push_front(cltr->threads, thrd);
1180	unlock (cltr->thread_list_lock);
1181	}
1182
1183	void unregister( cluster * cltr, $thread & thrd ) {
1184	lock (cltr->thread_list_lock __cfaabi_dbg_ctx2);
1185	remove(cltr->threads, thrd );
1186	cltr->nthreads -= 1;
1187	unlock(cltr->thread_list_lock);
1188	}
1189
1190	//-----------------------------------------------------------------------------
1191	// Debug
1192	__cfaabi_dbg_debug_do(
1193	extern "C" {
1194	void __cfaabi_dbg_record_lock(__spinlock_t & this, const char prev_name[]) {
1195	this.prev_name = prev_name;
1196	this.prev_thrd = kernelTLS.this_thread;
1197	}
1198
1199	void __cfaabi_dbg_record_thrd($thread & this, bool park, const char prev_name[]) {
1200	if(park) {
1201	this.park_caller = prev_name;
1202	this.park_stale = false;
1203	}
1204	else {
1205	this.unpark_caller = prev_name;
1206	this.unpark_stale = false;
1207	}
1208	}
1209	}
1210	)
1211
1212	//-----------------------------------------------------------------------------
1213	// Debug
1214	bool threading_enabled(void) __attribute__((const)) {
1215	return true;
1216	}
1217
1218	//-----------------------------------------------------------------------------
1219	// Statistics
1220	#if !defined(__CFA_NO_STATISTICS__)
1221	void print_halts( processor & this ) {
1222	this.print_halts = true;
1223	printf("Processor : %d - %s (%p)\n", this.id, this.name, (void*)&this);
1224	}
1225	#endif
1226	// Local Variables: //
1227	// mode: c //
1228	// tab-width: 4 //
1229	// End: //

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