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kernel.cfa@ c7816be

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

Last change on this file since c7816be was 13c5e19, checked in by Thierry Delisle <tdelisle@…>, 5 years ago
Moved snzi and subqueues outside of ready_queue.cfa. Added random.hfa with multiple prng. Minor optimizations to ready-queue Stats now track number of local pops( bias pops ) Fixed stats for io Fixed calculaton of nprocessors Fixed IO to work with new ready-queue
Property mode set to `100644`
File size: 37.0 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	idle{};
243
244	__cfadbg_print_safe(runtime_core, "Kernel : Starting core %p\n", &this);
245
246	this.stack = __create_pthread( &this.kernel_thread, __invoke_processor, (void *)&this );
247	__atomic_fetch_add( &cltr->nprocessors, 1u, __ATOMIC_SEQ_CST );
248
249	__cfadbg_print_safe(runtime_core, "Kernel : core %p created\n", &this);
250	}
251
252	void ^?{}(processor & this) with( this ){
253	if( ! __atomic_load_n(&do_terminate, __ATOMIC_ACQUIRE) ) {
254	__cfadbg_print_safe(runtime_core, "Kernel : core %p signaling termination\n", &this);
255
256	__atomic_store_n(&do_terminate, true, __ATOMIC_RELAXED);
257	__wake_proc( &this );
258
259	P( terminated );
260	verify( kernelTLS.this_processor != &this);
261	}
262
263	int err = pthread_join( kernel_thread, 0p );
264	if( err != 0 ) abort("KERNEL ERROR: joining processor %p caused error %s\n", &this, strerror(err));
265
266	free( this.stack );
267
268	__atomic_fetch_sub( &cltr->nprocessors, 1u, __ATOMIC_SEQ_CST );
269	}
270
271	void ?{}(cluster & this, const char name[], Duration preemption_rate, unsigned io_flags) with( this ) {
272	this.name = name;
273	this.preemption_rate = preemption_rate;
274	this.nprocessors = 0;
275	ready_queue{};
276
277	#if !defined(__CFA_NO_STATISTICS__)
278	print_stats = false;
279	stats = alloc();
280	__init_stats( stats );
281	#endif
282
283	threads{ __get };
284
285	__kernel_io_startup( this, io_flags, &this == mainCluster );
286
287	doregister(this);
288	}
289
290	void ^?{}(cluster & this) {
291	__kernel_io_shutdown( this, &this == mainCluster );
292
293	#if !defined(__CFA_NO_STATISTICS__)
294	if(this.print_stats) {
295	__print_stats( this.stats );
296	}
297	free( this.stats );
298	#endif
299
300	unregister(this);
301	}
302
303	//=============================================================================================
304	// Kernel Scheduling logic
305	//=============================================================================================
306	//Main of the processor contexts
307	void main(processorCtx_t & runner) {
308	// Because of a bug, we couldn't initialized the seed on construction
309	// Do it here
310	kernelTLS.rand_seed ^= rdtscl();
311
312	processor * this = runner.proc;
313	verify(this);
314
315	__cfadbg_print_safe(runtime_core, "Kernel : core %p starting\n", this);
316
317	// register the processor unless it's the main thread which is handled in the boot sequence
318	if(this != mainProcessor) {
319	this->id = doregister((__processor_id_t*)this);
320	// Lock the RWlock so no-one pushes/pops while we are changing the queue
321	uint_fast32_t last_size = ready_mutate_lock();
322
323	// Adjust the ready queue size
324	ready_queue_grow( this->cltr );
325
326	// Unlock the RWlock
327	ready_mutate_unlock( last_size );
328	}
329
330	{
331	// Setup preemption data
332	preemption_scope scope = { this };
333
334	__cfadbg_print_safe(runtime_core, "Kernel : core %p started\n", this);
335
336	$thread * readyThread = 0p;
337	for( unsigned int spin_count = 0; ! __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST); spin_count++ ) {
338	// Try to get the next thread
339	readyThread = __next_thread( this->cltr );
340
341	// Check if we actually found a thread
342	if( readyThread ) {
343	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
344	/* paranoid */ verifyf( readyThread->state == Ready \|\| readyThread->preempted != __NO_PREEMPTION, "state : %d, preempted %d\n", readyThread->state, readyThread->preempted);
345	/* paranoid */ verifyf( readyThread->link.next == 0p, "Expected null got %p", readyThread->link.next );
346	__builtin_prefetch( readyThread->context.SP );
347
348	// We found a thread run it
349	__run_thread(this, readyThread);
350
351	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
352	}
353	else {
354	// Block until a thread is ready
355	__halt(this);
356	}
357	}
358
359	__cfadbg_print_safe(runtime_core, "Kernel : core %p stopping\n", this);
360	}
361
362	V( this->terminated );
363
364	// unregister the processor unless it's the main thread which is handled in the boot sequence
365	if(this != mainProcessor) {
366	// Lock the RWlock so no-one pushes/pops while we are changing the queue
367	uint_fast32_t last_size = ready_mutate_lock();
368
369	// Adjust the ready queue size
370	ready_queue_shrink( this->cltr );
371
372	// Make sure we aren't on the idle queue
373	#if !defined(__CFA_NO_STATISTICS__)
374	bool removed =
375	#endif
376	unsafe_remove( this->cltr->idles, this );
377
378	#if !defined(__CFA_NO_STATISTICS__)
379	if(removed) __tls_stats()->ready.sleep.exits++;
380	#endif
381
382	// Unlock the RWlock
383	ready_mutate_unlock( last_size );
384
385	// Finally we don't need the read_lock any more
386	unregister((__processor_id_t*)this);
387	}
388	else {
389	// HACK : the coroutine context switch expects this_thread to be set
390	// and it make sense for it to be set in all other cases except here
391	// fake it
392	kernelTLS.this_thread = mainThread;
393	}
394
395	__cfadbg_print_safe(runtime_core, "Kernel : core %p terminated\n", this);
396	}
397
398	static int * __volatile_errno() __attribute__((noinline));
399	static int * __volatile_errno() { asm(""); return &errno; }
400
401	// KERNEL ONLY
402	// runThread runs a thread by context switching
403	// from the processor coroutine to the target thread
404	static void __run_thread(processor * this, $thread * thrd_dst) {
405	$coroutine * proc_cor = get_coroutine(this->runner);
406
407	// Update global state
408	kernelTLS.this_thread = thrd_dst;
409
410	// set state of processor coroutine to inactive
411	verify(proc_cor->state == Active);
412	proc_cor->state = Blocked;
413
414	// Actually run the thread
415	RUNNING: while(true) {
416	thrd_dst->preempted = __NO_PREEMPTION;
417	thrd_dst->state = Active;
418
419	__cfaabi_dbg_debug_do(
420	thrd_dst->park_stale = true;
421	thrd_dst->unpark_stale = true;
422	)
423
424	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
425	/* paranoid */ verify( kernelTLS.this_thread == thrd_dst );
426	/* 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
427	/* 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
428
429	// set context switch to the thread that the processor is executing
430	verify( thrd_dst->context.SP );
431	__cfactx_switch( &proc_cor->context, &thrd_dst->context );
432	// when __cfactx_switch returns we are back in the processor coroutine
433
434	/* 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 );
435	/* 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 );
436	/* paranoid */ verify( kernelTLS.this_thread == thrd_dst );
437	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
438
439
440	// We just finished running a thread, there are a few things that could have happened.
441	// 1 - Regular case : the thread has blocked and now one has scheduled it yet.
442	// 2 - Racy case : the thread has blocked but someone has already tried to schedule it.
443	// 4 - Preempted
444	// In case 1, we may have won a race so we can't write to the state again.
445	// In case 2, we lost the race so we now own the thread.
446
447	if(unlikely(thrd_dst->preempted != __NO_PREEMPTION)) {
448	// The thread was preempted, reschedule it and reset the flag
449	__schedule_thread( (__processor_id_t*)this, thrd_dst );
450	break RUNNING;
451	}
452
453	if(unlikely(thrd_dst->state == Halted)) {
454	// The thread has halted, it should never be scheduled/run again
455	// We may need to wake someone up here since
456	unpark( this->destroyer __cfaabi_dbg_ctx2 );
457	this->destroyer = 0p;
458	break RUNNING;
459	}
460
461	/* paranoid */ verify( thrd_dst->state == Active );
462	thrd_dst->state = Blocked;
463
464	// set state of processor coroutine to active and the thread to inactive
465	int old_ticket = __atomic_fetch_sub(&thrd_dst->ticket, 1, __ATOMIC_SEQ_CST);
466	__cfaabi_dbg_debug_do( thrd_dst->park_result = old_ticket; )
467	switch(old_ticket) {
468	case 1:
469	// This is case 1, the regular case, nothing more is needed
470	break RUNNING;
471	case 2:
472	// This is case 2, the racy case, someone tried to run this thread before it finished blocking
473	// In this case, just run it again.
474	continue RUNNING;
475	default:
476	// This makes no sense, something is wrong abort
477	abort();
478	}
479	}
480
481	// Just before returning to the processor, set the processor coroutine to active
482	proc_cor->state = Active;
483	kernelTLS.this_thread = 0p;
484	}
485
486	// KERNEL_ONLY
487	void returnToKernel() {
488	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
489	$coroutine * proc_cor = get_coroutine(kernelTLS.this_processor->runner);
490	$thread * thrd_src = kernelTLS.this_thread;
491
492	// Run the thread on this processor
493	{
494	int local_errno = *__volatile_errno();
495	#if defined( __i386 ) \|\| defined( __x86_64 )
496	__x87_store;
497	#endif
498	verify( proc_cor->context.SP );
499	__cfactx_switch( &thrd_src->context, &proc_cor->context );
500	#if defined( __i386 ) \|\| defined( __x86_64 )
501	__x87_load;
502	#endif
503	*__volatile_errno() = local_errno;
504	}
505
506	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
507	/* 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 );
508	/* 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 );
509	}
510
511	// KERNEL_ONLY
512	// Context invoker for processors
513	// This is the entry point for processors (kernel threads)
514	// It effectively constructs a coroutine by stealing the pthread stack
515	static void * __invoke_processor(void * arg) {
516	#if !defined( __CFA_NO_STATISTICS__ )
517	__stats_t local_stats;
518	__init_stats( &local_stats );
519	kernelTLS.this_stats = &local_stats;
520	#endif
521
522	processor * proc = (processor *) arg;
523	kernelTLS.this_processor = proc;
524	kernelTLS.this_thread = 0p;
525	kernelTLS.preemption_state.[enabled, disable_count] = [false, 1];
526	// SKULLDUGGERY: We want to create a context for the processor coroutine
527	// which is needed for the 2-step context switch. However, there is no reason
528	// to waste the perfectly valid stack create by pthread.
529	current_stack_info_t info;
530	__stack_t ctx;
531	info.storage = &ctx;
532	(proc->runner){ proc, &info };
533
534	__cfaabi_dbg_print_safe("Coroutine : created stack %p\n", get_coroutine(proc->runner)->stack.storage);
535
536	//Set global state
537	kernelTLS.this_thread = 0p;
538
539	//We now have a proper context from which to schedule threads
540	__cfadbg_print_safe(runtime_core, "Kernel : core %p created (%p, %p)\n", proc, &proc->runner, &ctx);
541
542	// SKULLDUGGERY: Since the coroutine doesn't have its own stack, we can't
543	// resume it to start it like it normally would, it will just context switch
544	// back to here. Instead directly call the main since we already are on the
545	// appropriate stack.
546	get_coroutine(proc->runner)->state = Active;
547	main( proc->runner );
548	get_coroutine(proc->runner)->state = Halted;
549
550	// Main routine of the core returned, the core is now fully terminated
551	__cfadbg_print_safe(runtime_core, "Kernel : core %p main ended (%p)\n", proc, &proc->runner);
552
553	#if !defined(__CFA_NO_STATISTICS__)
554	__tally_stats(proc->cltr->stats, &local_stats);
555	#endif
556
557	return 0p;
558	}
559
560	static void Abort( int ret, const char func[] ) {
561	if ( ret ) { // pthread routines return errno values
562	abort( "%s : internal error, error(%d) %s.", func, ret, strerror( ret ) );
563	} // if
564	} // Abort
565
566	void * __create_pthread( pthread_t * pthread, void * (start)(void ), void * arg ) {
567	pthread_attr_t attr;
568
569	Abort( pthread_attr_init( &attr ), "pthread_attr_init" ); // initialize attribute
570
571	size_t stacksize;
572	// default stack size, normally defined by shell limit
573	Abort( pthread_attr_getstacksize( &attr, &stacksize ), "pthread_attr_getstacksize" );
574	assert( stacksize >= PTHREAD_STACK_MIN );
575
576	void * stack;
577	__cfaabi_dbg_debug_do(
578	stack = memalign( __page_size, stacksize + __page_size );
579	// pthread has no mechanism to create the guard page in user supplied stack.
580	if ( mprotect( stack, __page_size, PROT_NONE ) == -1 ) {
581	abort( "mprotect : internal error, mprotect failure, error(%d) %s.", errno, strerror( errno ) );
582	} // if
583	);
584	__cfaabi_dbg_no_debug_do(
585	stack = malloc( stacksize );
586	);
587
588	Abort( pthread_attr_setstack( &attr, stack, stacksize ), "pthread_attr_setstack" );
589
590	Abort( pthread_create( pthread, &attr, start, arg ), "pthread_create" );
591	return stack;
592	}
593
594	// KERNEL_ONLY
595	static void __kernel_first_resume( processor * this ) {
596	$thread * src = mainThread;
597	$coroutine * dst = get_coroutine(this->runner);
598
599	verify( ! kernelTLS.preemption_state.enabled );
600
601	kernelTLS.this_thread->curr_cor = dst;
602	__stack_prepare( &dst->stack, 65000 );
603	__cfactx_start(main, dst, this->runner, __cfactx_invoke_coroutine);
604
605	verify( ! kernelTLS.preemption_state.enabled );
606
607	dst->last = &src->self_cor;
608	dst->starter = dst->starter ? dst->starter : &src->self_cor;
609
610	// make sure the current state is still correct
611	/* paranoid */ verify(src->state == Ready);
612
613	// context switch to specified coroutine
614	verify( dst->context.SP );
615	__cfactx_switch( &src->context, &dst->context );
616	// when __cfactx_switch returns we are back in the src coroutine
617
618	mainThread->curr_cor = &mainThread->self_cor;
619
620	// make sure the current state has been update
621	/* paranoid */ verify(src->state == Active);
622
623	verify( ! kernelTLS.preemption_state.enabled );
624	}
625
626	// KERNEL_ONLY
627	static void __kernel_last_resume( processor * this ) {
628	$coroutine * src = &mainThread->self_cor;
629	$coroutine * dst = get_coroutine(this->runner);
630
631	verify( ! kernelTLS.preemption_state.enabled );
632	verify( dst->starter == src );
633	verify( dst->context.SP );
634
635	// SKULLDUGGERY in debug the processors check that the
636	// stack is still within the limit of the stack limits after running a thread.
637	// that check doesn't make sense if we context switch to the processor using the
638	// coroutine semantics. Since this is a special case, use the current context
639	// info to populate these fields.
640	__cfaabi_dbg_debug_do(
641	__stack_context_t ctx;
642	CtxGet( ctx );
643	mainThread->context.SP = ctx.SP;
644	mainThread->context.FP = ctx.FP;
645	)
646
647	// context switch to the processor
648	__cfactx_switch( &src->context, &dst->context );
649	}
650
651	//-----------------------------------------------------------------------------
652	// Scheduler routines
653	// KERNEL ONLY
654	void __schedule_thread( struct __processor_id_t * id, $thread * thrd ) {
655	/* paranoid */ verify( thrd );
656	/* paranoid */ verify( thrd->state != Halted );
657	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
658	/* paranoid */ #if defined( __CFA_WITH_VERIFY__ )
659	/* paranoid */ if( thrd->state == Blocked \|\| thrd->state == Start ) assertf( thrd->preempted == __NO_PREEMPTION,
660	"Error inactive thread marked as preempted, state %d, preemption %d\n", thrd->state, thrd->preempted );
661	/* paranoid */ if( thrd->preempted != __NO_PREEMPTION ) assertf(thrd->state == Active,
662	"Error preempted thread marked as not currently running, state %d, preemption %d\n", thrd->state, thrd->preempted );
663	/* paranoid */ #endif
664	/* paranoid */ verifyf( thrd->link.next == 0p, "Expected null got %p", thrd->link.next );
665
666	if (thrd->preempted == __NO_PREEMPTION) thrd->state = Ready;
667
668	ready_schedule_lock ( id );
669	push( thrd->curr_cluster, thrd );
670
671	#if !defined(__CFA_NO_STATISTICS__)
672	bool woke =
673	#endif
674	__wake_one(id, thrd->curr_cluster);
675
676	#if !defined(__CFA_NO_STATISTICS__)
677	if(woke) __tls_stats()->ready.sleep.wakes++;
678	#endif
679	ready_schedule_unlock( id );
680
681	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
682	}
683
684	// KERNEL ONLY
685	static $thread * __next_thread(cluster * this) with( *this ) {
686	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
687
688	ready_schedule_lock ( (__processor_id_t*)kernelTLS.this_processor );
689	$thread * head = pop( this );
690	ready_schedule_unlock( (__processor_id_t*)kernelTLS.this_processor );
691
692	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
693	return head;
694	}
695
696	// KERNEL ONLY
697	static bool __has_next_thread(cluster * this) with( *this ) {
698	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
699
700	ready_schedule_lock ( (__processor_id_t*)kernelTLS.this_processor );
701	bool not_empty = query( this );
702	ready_schedule_unlock( (__processor_id_t*)kernelTLS.this_processor );
703
704	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
705	return not_empty;
706	}
707
708	// KERNEL ONLY unpark with out disabling interrupts
709	void __unpark( struct __processor_id_t * id, $thread * thrd __cfaabi_dbg_ctx_param2 ) {
710	// record activity
711	__cfaabi_dbg_debug_do( char * old_caller = thrd->unpark_caller; )
712	__cfaabi_dbg_record_thrd( *thrd, false, caller );
713
714	int old_ticket = __atomic_fetch_add(&thrd->ticket, 1, __ATOMIC_SEQ_CST);
715	__cfaabi_dbg_debug_do( thrd->unpark_result = old_ticket; thrd->unpark_state = thrd->state; )
716	switch(old_ticket) {
717	case 1:
718	// Wake won the race, the thread will reschedule/rerun itself
719	break;
720	case 0:
721	/* paranoid */ verify( ! thrd->preempted != __NO_PREEMPTION );
722	/* paranoid */ verify( thrd->state == Blocked );
723
724	// Wake lost the race,
725	__schedule_thread( id, thrd );
726	break;
727	default:
728	// This makes no sense, something is wrong abort
729	abort();
730	}
731	}
732
733	void unpark( $thread * thrd __cfaabi_dbg_ctx_param2 ) {
734	if( !thrd ) return;
735
736	disable_interrupts();
737	__unpark( (__processor_id_t*)kernelTLS.this_processor, thrd __cfaabi_dbg_ctx_fwd2 );
738	enable_interrupts( __cfaabi_dbg_ctx );
739	}
740
741	void park( __cfaabi_dbg_ctx_param ) {
742	/* paranoid */ verify( kernelTLS.preemption_state.enabled );
743	disable_interrupts();
744	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
745	/* paranoid */ verify( kernelTLS.this_thread->preempted == __NO_PREEMPTION );
746
747	// record activity
748	__cfaabi_dbg_record_thrd( *kernelTLS.this_thread, true, caller );
749
750	returnToKernel();
751
752	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
753	enable_interrupts( __cfaabi_dbg_ctx );
754	/* paranoid */ verify( kernelTLS.preemption_state.enabled );
755
756	}
757
758	// KERNEL ONLY
759	void __leave_thread() {
760	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
761	returnToKernel();
762	abort();
763	}
764
765	// KERNEL ONLY
766	bool force_yield( __Preemption_Reason reason ) {
767	/* paranoid */ verify( kernelTLS.preemption_state.enabled );
768	disable_interrupts();
769	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
770
771	$thread * thrd = kernelTLS.this_thread;
772	/* paranoid */ verify(thrd->state == Active);
773
774	// SKULLDUGGERY: It is possible that we are preempting this thread just before
775	// it was going to park itself. If that is the case and it is already using the
776	// intrusive fields then we can't use them to preempt the thread
777	// If that is the case, abandon the preemption.
778	bool preempted = false;
779	if(thrd->link.next == 0p) {
780	preempted = true;
781	thrd->preempted = reason;
782	returnToKernel();
783	}
784
785	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
786	enable_interrupts_noPoll();
787	/* paranoid */ verify( kernelTLS.preemption_state.enabled );
788
789	return preempted;
790	}
791
792	//=============================================================================================
793	// Kernel Setup logic
794	//=============================================================================================
795	//-----------------------------------------------------------------------------
796	// Kernel boot procedures
797	static void __kernel_startup(void) {
798	verify( ! kernelTLS.preemption_state.enabled );
799	__cfadbg_print_safe(runtime_core, "Kernel : Starting\n");
800
801	__page_size = sysconf( _SC_PAGESIZE );
802
803	__cfa_dbg_global_clusters.list{ __get };
804	__cfa_dbg_global_clusters.lock{};
805
806	// Initialize the global scheduler lock
807	__scheduler_lock = (__scheduler_RWLock_t*)&storage___scheduler_lock;
808	(*__scheduler_lock){};
809
810	// Initialize the main cluster
811	mainCluster = (cluster *)&storage_mainCluster;
812	(*mainCluster){"Main Cluster"};
813
814	__cfadbg_print_safe(runtime_core, "Kernel : Main cluster ready\n");
815
816	// Start by initializing the main thread
817	// SKULLDUGGERY: the mainThread steals the process main thread
818	// which will then be scheduled by the mainProcessor normally
819	mainThread = ($thread *)&storage_mainThread;
820	current_stack_info_t info;
821	info.storage = (__stack_t*)&storage_mainThreadCtx;
822	(*mainThread){ &info };
823
824	__cfadbg_print_safe(runtime_core, "Kernel : Main thread ready\n");
825
826
827
828	// Construct the processor context of the main processor
829	void ?{}(processorCtx_t & this, processor * proc) {
830	(this.__cor){ "Processor" };
831	this.__cor.starter = 0p;
832	this.proc = proc;
833	}
834
835	void ?{}(processor & this) with( this ) {
836	name = "Main Processor";
837	cltr = mainCluster;
838	terminated{ 0 };
839	do_terminate = false;
840	preemption_alarm = 0p;
841	pending_preemption = false;
842	kernel_thread = pthread_self();
843	id = -1u;
844
845	runner{ &this };
846	__cfadbg_print_safe(runtime_core, "Kernel : constructed main processor context %p\n", &runner);
847
848	__atomic_fetch_add( &cltr->nprocessors, 1u, __ATOMIC_SEQ_CST );
849	}
850
851	// Initialize the main processor and the main processor ctx
852	// (the coroutine that contains the processing control flow)
853	mainProcessor = (processor *)&storage_mainProcessor;
854	(*mainProcessor){};
855
856	mainProcessor->id = doregister( (__processor_id_t*)mainProcessor);
857
858	//initialize the global state variables
859	kernelTLS.this_processor = mainProcessor;
860	kernelTLS.this_thread = mainThread;
861
862	#if !defined( __CFA_NO_STATISTICS__ )
863	kernelTLS.this_stats = (__stats_t *)& storage_mainProcStats;
864	__init_stats( kernelTLS.this_stats );
865	#endif
866
867	// Enable preemption
868	kernel_start_preemption();
869
870	// Add the main thread to the ready queue
871	// once resume is called on mainProcessor->runner the mainThread needs to be scheduled like any normal thread
872	__schedule_thread((__processor_id_t *)mainProcessor, mainThread);
873
874	// SKULLDUGGERY: Force a context switch to the main processor to set the main thread's context to the current UNIX
875	// context. Hence, the main thread does not begin through __cfactx_invoke_thread, like all other threads. The trick here is that
876	// mainThread is on the ready queue when this call is made.
877	__kernel_first_resume( kernelTLS.this_processor );
878
879
880	// THE SYSTEM IS NOW COMPLETELY RUNNING
881
882
883	// Now that the system is up, finish creating systems that need threading
884	__kernel_io_finish_start( *mainCluster );
885
886
887	__cfadbg_print_safe(runtime_core, "Kernel : Started\n--------------------------------------------------\n\n");
888
889	verify( ! kernelTLS.preemption_state.enabled );
890	enable_interrupts( __cfaabi_dbg_ctx );
891	verify( TL_GET( preemption_state.enabled ) );
892	}
893
894	static void __kernel_shutdown(void) {
895	//Before we start shutting things down, wait for systems that need threading to shutdown
896	__kernel_io_prepare_stop( *mainCluster );
897
898	/* paranoid */ verify( TL_GET( preemption_state.enabled ) );
899	disable_interrupts();
900	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
901
902	__cfadbg_print_safe(runtime_core, "\n--------------------------------------------------\nKernel : Shutting down\n");
903
904	// SKULLDUGGERY: Notify the mainProcessor it needs to terminates.
905	// When its coroutine terminates, it return control to the mainThread
906	// which is currently here
907	__atomic_store_n(&mainProcessor->do_terminate, true, __ATOMIC_RELEASE);
908	__kernel_last_resume( kernelTLS.this_processor );
909	mainThread->self_cor.state = Halted;
910
911	// THE SYSTEM IS NOW COMPLETELY STOPPED
912
913	// Disable preemption
914	kernel_stop_preemption();
915
916	unregister((__processor_id_t*)mainProcessor);
917
918	// Destroy the main processor and its context in reverse order of construction
919	// These were manually constructed so we need manually destroy them
920	void ^?{}(processor & this) with( this ){
921	/* paranoid */ verify( this.do_terminate == true );
922	__atomic_fetch_sub( &cltr->nprocessors, 1u, __ATOMIC_SEQ_CST );
923	__cfaabi_dbg_print_safe("Kernel : destroyed main processor context %p\n", &runner);
924	}
925
926	^(*mainProcessor){};
927
928	// Final step, destroy the main thread since it is no longer needed
929
930	// Since we provided a stack to this taxk it will not destroy anything
931	/* paranoid / verify(mainThread->self_cor.stack.storage == (__stack_t)(((uintptr_t)&storage_mainThreadCtx)\| 0x1));
932	^(*mainThread){};
933
934	^(*mainCluster){};
935
936	^(*__scheduler_lock){};
937
938	^(__cfa_dbg_global_clusters.list){};
939	^(__cfa_dbg_global_clusters.lock){};
940
941	__cfadbg_print_safe(runtime_core, "Kernel : Shutdown complete\n");
942	}
943
944	//=============================================================================================
945	// Kernel Idle Sleep
946	//=============================================================================================
947	// Wake a thread from the front if there are any
948	static bool __wake_one(struct __processor_id_t * id, cluster * this) {
949	/* paranoid */ verify( ready_schedule_islocked( id ) );
950
951	// Check if there is a sleeping processor
952	processor * p = pop(this->idles);
953
954	// If no one is sleeping, we are done
955	if( 0p == p ) return false;
956
957	// We found a processor, wake it up
958	post( p->idle );
959
960	return true;
961	}
962
963	// Unconditionnaly wake a thread
964	static bool __wake_proc(processor * this) {
965	__cfadbg_print_safe(runtime_core, "Kernel : waking Processor %p\n", this);
966
967	disable_interrupts();
968	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
969	bool ret = post( this->idle );
970	enable_interrupts( __cfaabi_dbg_ctx );
971
972	return ret;
973	}
974
975	static void __halt(processor * this) with( *this ) {
976	if( do_terminate ) return;
977
978	#if !defined(__CFA_NO_STATISTICS__)
979	__tls_stats()->ready.sleep.halts++;
980	#endif
981	// Push self to queue
982	push(cltr->idles, *this);
983
984	// Makre sure we don't miss a thread
985	if( __has_next_thread(cltr) ) {
986	// A thread was posted, make sure a processor is woken up
987	struct __processor_id_t id = (struct __processor_id_t ) this;
988	ready_schedule_lock ( id );
989	__wake_one( id, cltr );
990	ready_schedule_unlock( id );
991	#if !defined(__CFA_NO_STATISTICS__)
992	__tls_stats()->ready.sleep.cancels++;
993	#endif
994	}
995
996	wait( idle );
997	}
998
999	//=============================================================================================
1000	// Unexpected Terminating logic
1001	//=============================================================================================
1002	static __spinlock_t kernel_abort_lock;
1003	static bool kernel_abort_called = false;
1004
1005	void * kernel_abort(void) __attribute__ ((__nothrow__)) {
1006	// abort cannot be recursively entered by the same or different processors because all signal handlers return when
1007	// the globalAbort flag is true.
1008	lock( kernel_abort_lock __cfaabi_dbg_ctx2 );
1009
1010	// first task to abort ?
1011	if ( kernel_abort_called ) { // not first task to abort ?
1012	unlock( kernel_abort_lock );
1013
1014	sigset_t mask;
1015	sigemptyset( &mask );
1016	sigaddset( &mask, SIGALRM ); // block SIGALRM signals
1017	sigaddset( &mask, SIGUSR1 ); // block SIGALRM signals
1018	sigsuspend( &mask ); // block the processor to prevent further damage during abort
1019	_exit( EXIT_FAILURE ); // if processor unblocks before it is killed, terminate it
1020	}
1021	else {
1022	kernel_abort_called = true;
1023	unlock( kernel_abort_lock );
1024	}
1025
1026	return kernelTLS.this_thread;
1027	}
1028
1029	void kernel_abort_msg( void * kernel_data, char * abort_text, int abort_text_size ) {
1030	$thread * thrd = kernel_data;
1031
1032	if(thrd) {
1033	int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
1034	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
1035
1036	if ( &thrd->self_cor != thrd->curr_cor ) {
1037	len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
1038	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
1039	}
1040	else {
1041	__cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
1042	}
1043	}
1044	else {
1045	int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
1046	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
1047	}
1048	}
1049
1050	int kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
1051	return get_coroutine(kernelTLS.this_thread) == get_coroutine(mainThread) ? 4 : 2;
1052	}
1053
1054	static __spinlock_t kernel_debug_lock;
1055
1056	extern "C" {
1057	void __cfaabi_bits_acquire() {
1058	lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
1059	}
1060
1061	void __cfaabi_bits_release() {
1062	unlock( kernel_debug_lock );
1063	}
1064	}
1065
1066	//=============================================================================================
1067	// Kernel Utilities
1068	//=============================================================================================
1069	//-----------------------------------------------------------------------------
1070	// Locks
1071	void ?{}( semaphore & this, int count = 1 ) {
1072	(this.lock){};
1073	this.count = count;
1074	(this.waiting){};
1075	}
1076	void ^?{}(semaphore & this) {}
1077
1078	bool P(semaphore & this) with( this ){
1079	lock( lock __cfaabi_dbg_ctx2 );
1080	count -= 1;
1081	if ( count < 0 ) {
1082	// queue current task
1083	append( waiting, kernelTLS.this_thread );
1084
1085	// atomically release spin lock and block
1086	unlock( lock );
1087	park( __cfaabi_dbg_ctx );
1088	return true;
1089	}
1090	else {
1091	unlock( lock );
1092	return false;
1093	}
1094	}
1095
1096	bool V(semaphore & this) with( this ) {
1097	$thread * thrd = 0p;
1098	lock( lock __cfaabi_dbg_ctx2 );
1099	count += 1;
1100	if ( count <= 0 ) {
1101	// remove task at head of waiting list
1102	thrd = pop_head( waiting );
1103	}
1104
1105	unlock( lock );
1106
1107	// make new owner
1108	unpark( thrd __cfaabi_dbg_ctx2 );
1109
1110	return thrd != 0p;
1111	}
1112
1113	bool V(semaphore & this, unsigned diff) with( this ) {
1114	$thread * thrd = 0p;
1115	lock( lock __cfaabi_dbg_ctx2 );
1116	int release = max(-count, (int)diff);
1117	count += diff;
1118	for(release) {
1119	unpark( pop_head( waiting ) __cfaabi_dbg_ctx2 );
1120	}
1121
1122	unlock( lock );
1123
1124	return thrd != 0p;
1125	}
1126
1127	//-----------------------------------------------------------------------------
1128	// Global Queues
1129	void doregister( cluster & cltr ) {
1130	lock ( __cfa_dbg_global_clusters.lock __cfaabi_dbg_ctx2);
1131	push_front( __cfa_dbg_global_clusters.list, cltr );
1132	unlock ( __cfa_dbg_global_clusters.lock );
1133	}
1134
1135	void unregister( cluster & cltr ) {
1136	lock ( __cfa_dbg_global_clusters.lock __cfaabi_dbg_ctx2);
1137	remove( __cfa_dbg_global_clusters.list, cltr );
1138	unlock( __cfa_dbg_global_clusters.lock );
1139	}
1140
1141	void doregister( cluster * cltr, $thread & thrd ) {
1142	lock (cltr->thread_list_lock __cfaabi_dbg_ctx2);
1143	cltr->nthreads += 1;
1144	push_front(cltr->threads, thrd);
1145	unlock (cltr->thread_list_lock);
1146	}
1147
1148	void unregister( cluster * cltr, $thread & thrd ) {
1149	lock (cltr->thread_list_lock __cfaabi_dbg_ctx2);
1150	remove(cltr->threads, thrd );
1151	cltr->nthreads -= 1;
1152	unlock(cltr->thread_list_lock);
1153	}
1154
1155	//-----------------------------------------------------------------------------
1156	// Debug
1157	__cfaabi_dbg_debug_do(
1158	extern "C" {
1159	void __cfaabi_dbg_record_lock(__spinlock_t & this, const char prev_name[]) {
1160	this.prev_name = prev_name;
1161	this.prev_thrd = kernelTLS.this_thread;
1162	}
1163
1164	void __cfaabi_dbg_record_thrd($thread & this, bool park, const char prev_name[]) {
1165	if(park) {
1166	this.park_caller = prev_name;
1167	this.park_stale = false;
1168	}
1169	else {
1170	this.unpark_caller = prev_name;
1171	this.unpark_stale = false;
1172	}
1173	}
1174	}
1175	)
1176
1177	//-----------------------------------------------------------------------------
1178	// Debug
1179	bool threading_enabled(void) __attribute__((const)) {
1180	return true;
1181	}
1182	// Local Variables: //
1183	// mode: c //
1184	// tab-width: 4 //
1185	// End: //

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