Context Navigation

kernel.cfa @ 276ae57e

ADTarm-ehast-experimentalenumforall-pointer-decayjacob/cs343-translationnew-astnew-ast-unique-exprpthread-emulationqualifiedEnum

Last change on this file since 276ae57e was 276ae57e, checked in by Thierry Delisle <tdelisle@…>, 4 years ago
Fix yesterday's checks where the stale flag was wrong
Property mode set to `100644`
File size: 31.5 KB

Line
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 Feb 4 13:03:15 2020
13	// Update Count : 58
14	//
15
16	#define __cforall_thread__
17
18	//C Includes
19	#include <stddef.h>
20	#include <errno.h>
21	#include <string.h>
22	extern "C" {
23	#include <stdio.h>
24	#include <fenv.h>
25	#include <sys/resource.h>
26	#include <signal.h>
27	#include <unistd.h>
28	#include <limits.h> // PTHREAD_STACK_MIN
29	#include <sys/mman.h> // mprotect
30	}
31
32	//CFA Includes
33	#include "time.hfa"
34	#include "kernel_private.hfa"
35	#include "preemption.hfa"
36	#include "startup.hfa"
37
38	//Private includes
39	#define __CFA_INVOKE_PRIVATE__
40	#include "invoke.h"
41
42	//-----------------------------------------------------------------------------
43	// Some assembly required
44	#if defined( __i386 )
45	#define CtxGet( ctx ) \
46	__asm__ volatile ( \
47	"movl %%esp,%0\n"\
48	"movl %%ebp,%1\n"\
49	: "=rm" (ctx.SP),\
50	"=rm" (ctx.FP) \
51	)
52
53	// mxcr : SSE Status and Control bits (control bits are preserved across function calls)
54	// fcw : X87 FPU control word (preserved across function calls)
55	#define __x87_store \
56	uint32_t __mxcr; \
57	uint16_t __fcw; \
58	__asm__ volatile ( \
59	"stmxcsr %0\n" \
60	"fnstcw %1\n" \
61	: "=m" (__mxcr),\
62	"=m" (__fcw) \
63	)
64
65	#define __x87_load \
66	__asm__ volatile ( \
67	"fldcw %1\n" \
68	"ldmxcsr %0\n" \
69	::"m" (__mxcr),\
70	"m" (__fcw) \
71	)
72
73	#elif defined( __x86_64 )
74	#define CtxGet( ctx ) \
75	__asm__ volatile ( \
76	"movq %%rsp,%0\n"\
77	"movq %%rbp,%1\n"\
78	: "=rm" (ctx.SP),\
79	"=rm" (ctx.FP) \
80	)
81
82	#define __x87_store \
83	uint32_t __mxcr; \
84	uint16_t __fcw; \
85	__asm__ volatile ( \
86	"stmxcsr %0\n" \
87	"fnstcw %1\n" \
88	: "=m" (__mxcr),\
89	"=m" (__fcw) \
90	)
91
92	#define __x87_load \
93	__asm__ volatile ( \
94	"fldcw %1\n" \
95	"ldmxcsr %0\n" \
96	:: "m" (__mxcr),\
97	"m" (__fcw) \
98	)
99
100
101	#elif defined( __ARM_ARCH )
102	#define CtxGet( ctx ) __asm__ ( \
103	"mov %0,%%sp\n" \
104	"mov %1,%%r11\n" \
105	: "=rm" (ctx.SP), "=rm" (ctx.FP) )
106	#else
107	#error unknown hardware architecture
108	#endif
109
110	//-----------------------------------------------------------------------------
111	//Start and stop routine for the kernel, declared first to make sure they run first
112	static void __kernel_startup (void) __attribute__(( constructor( STARTUP_PRIORITY_KERNEL ) ));
113	static void __kernel_shutdown(void) __attribute__(( destructor ( STARTUP_PRIORITY_KERNEL ) ));
114
115	//-----------------------------------------------------------------------------
116	// Kernel storage
117	KERNEL_STORAGE(cluster, mainCluster);
118	KERNEL_STORAGE(processor, mainProcessor);
119	KERNEL_STORAGE($thread, mainThread);
120	KERNEL_STORAGE(__stack_t, mainThreadCtx);
121
122	cluster * mainCluster;
123	processor * mainProcessor;
124	$thread * mainThread;
125
126	extern "C" {
127	struct { __dllist_t(cluster) list; __spinlock_t lock; } __cfa_dbg_global_clusters;
128	}
129
130	size_t __page_size = 0;
131
132	//-----------------------------------------------------------------------------
133	// Global state
134	thread_local struct KernelThreadData kernelTLS __attribute__ ((tls_model ( "initial-exec" ))) = {
135	NULL, // cannot use 0p
136	NULL,
137	{ 1, false, false },
138	6u //this should be seeded better but due to a bug calling rdtsc doesn't work
139	};
140
141	//-----------------------------------------------------------------------------
142	// Struct to steal stack
143	struct current_stack_info_t {
144	__stack_t * storage; // pointer to stack object
145	void * base; // base of stack
146	void * limit; // stack grows towards stack limit
147	void * context; // address of cfa_context_t
148	};
149
150	void ?{}( current_stack_info_t & this ) {
151	__stack_context_t ctx;
152	CtxGet( ctx );
153	this.base = ctx.FP;
154
155	rlimit r;
156	getrlimit( RLIMIT_STACK, &r);
157	size_t size = r.rlim_cur;
158
159	this.limit = (void *)(((intptr_t)this.base) - size);
160	this.context = &storage_mainThreadCtx;
161	}
162
163	//-----------------------------------------------------------------------------
164	// Main thread construction
165
166	void ?{}( $coroutine & this, current_stack_info_t * info) with( this ) {
167	stack.storage = info->storage;
168	with(*stack.storage) {
169	limit = info->limit;
170	base = info->base;
171	}
172	__attribute__((may_alias)) intptr_t * istorage = (intptr_t*) &stack.storage;
173	*istorage \|= 0x1;
174	name = "Main Thread";
175	state = Start;
176	starter = 0p;
177	last = 0p;
178	cancellation = 0p;
179	}
180
181	void ?{}( $thread & this, current_stack_info_t * info) with( this ) {
182	state = Start;
183	self_cor{ info };
184	curr_cor = &self_cor;
185	curr_cluster = mainCluster;
186	self_mon.owner = &this;
187	self_mon.recursion = 1;
188	self_mon_p = &self_mon;
189	next = 0p;
190
191	node.next = 0p;
192	node.prev = 0p;
193	doregister(curr_cluster, this);
194
195	monitors{ &self_mon_p, 1, (fptr_t)0 };
196	}
197
198	//-----------------------------------------------------------------------------
199	// Processor coroutine
200	void ?{}(processorCtx_t & this) {
201
202	}
203
204	// Construct the processor context of non-main processors
205	static void ?{}(processorCtx_t & this, processor * proc, current_stack_info_t * info) {
206	(this.__cor){ info };
207	this.proc = proc;
208	}
209
210	static void * __invoke_processor(void * arg);
211
212	void ?{}(processor & this, const char name[], cluster & cltr) with( this ) {
213	this.name = name;
214	this.cltr = &cltr;
215	terminated{ 0 };
216	destroyer = 0p;
217	do_terminate = false;
218	preemption_alarm = 0p;
219	pending_preemption = false;
220	runner.proc = &this;
221
222	idleLock{};
223
224	__cfaabi_dbg_print_safe("Kernel : Starting core %p\n", &this);
225
226	this.stack = __create_pthread( &this.kernel_thread, __invoke_processor, (void *)&this );
227
228	__cfaabi_dbg_print_safe("Kernel : core %p started\n", &this);
229	}
230
231	void ^?{}(processor & this) with( this ){
232	if( ! __atomic_load_n(&do_terminate, __ATOMIC_ACQUIRE) ) {
233	__cfaabi_dbg_print_safe("Kernel : core %p signaling termination\n", &this);
234
235	__atomic_store_n(&do_terminate, true, __ATOMIC_RELAXED);
236	wake( &this );
237
238	P( terminated );
239	verify( kernelTLS.this_processor != &this);
240	}
241
242	pthread_join( kernel_thread, 0p );
243	free( this.stack );
244	}
245
246	void ?{}(cluster & this, const char name[], Duration preemption_rate) with( this ) {
247	this.name = name;
248	this.preemption_rate = preemption_rate;
249	ready_queue{};
250	ready_queue_lock{};
251
252	procs{ __get };
253	idles{ __get };
254	threads{ __get };
255
256	doregister(this);
257	}
258
259	void ^?{}(cluster & this) {
260	unregister(this);
261	}
262
263	//=============================================================================================
264	// Kernel Scheduling logic
265	//=============================================================================================
266	static $thread * __next_thread(cluster * this);
267	static void __run_thread(processor * this, $thread * dst);
268	static void __halt(processor * this);
269
270	//Main of the processor contexts
271	void main(processorCtx_t & runner) {
272	// Because of a bug, we couldn't initialized the seed on construction
273	// Do it here
274	kernelTLS.rand_seed ^= rdtscl();
275
276	processor * this = runner.proc;
277	verify(this);
278
279	__cfaabi_dbg_print_safe("Kernel : core %p starting\n", this);
280
281	doregister(this->cltr, this);
282
283	{
284	// Setup preemption data
285	preemption_scope scope = { this };
286
287	__cfaabi_dbg_print_safe("Kernel : core %p started\n", this);
288
289	$thread * readyThread = 0p;
290	for( unsigned int spin_count = 0; ! __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST); spin_count++ ) {
291	readyThread = __next_thread( this->cltr );
292
293	if(readyThread) {
294	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
295	/* paranoid */ verifyf( readyThread->state == Inactive \|\| readyThread->state == Start \|\| readyThread->preempted != __NO_PREEMPTION, "state : %d, preempted %d\n", readyThread->state, readyThread->preempted);
296	/* paranoid */ verifyf( readyThread->next == 0p, "Expected null got %p", readyThread->next );
297
298	__run_thread(this, readyThread);
299
300	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
301
302	spin_count = 0;
303	} else {
304	// spin(this, &spin_count);
305	__halt(this);
306	}
307	}
308
309	__cfaabi_dbg_print_safe("Kernel : core %p stopping\n", this);
310	}
311
312	unregister(this->cltr, this);
313
314	V( this->terminated );
315
316	__cfaabi_dbg_print_safe("Kernel : core %p terminated\n", this);
317	}
318
319	static int * __volatile_errno() __attribute__((noinline));
320	static int * __volatile_errno() { asm(""); return &errno; }
321
322	// KERNEL ONLY
323	// runThread runs a thread by context switching
324	// from the processor coroutine to the target thread
325	static void __run_thread(processor * this, $thread * thrd_dst) {
326	$coroutine * proc_cor = get_coroutine(this->runner);
327
328	// Update global state
329	kernelTLS.this_thread = thrd_dst;
330
331	// set state of processor coroutine to inactive
332	verify(proc_cor->state == Active);
333	proc_cor->state = Inactive;
334
335	// Actually run the thread
336	RUNNING: while(true) {
337	if(unlikely(thrd_dst->preempted)) {
338	thrd_dst->preempted = __NO_PREEMPTION;
339	verify(thrd_dst->state == Active \|\| thrd_dst->state == Rerun);
340	} else {
341	verify(thrd_dst->state == Start \|\| thrd_dst->state == Primed \|\| thrd_dst->state == Inactive);
342	thrd_dst->state = Active;
343	}
344
345	__cfaabi_dbg_debug_do(
346	thrd_dst->park_stale = true;
347	thrd_dst->unpark_stale = true;
348	)
349
350	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
351	/* 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
352	/* 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
353
354	// set context switch to the thread that the processor is executing
355	verify( thrd_dst->context.SP );
356	__cfactx_switch( &proc_cor->context, &thrd_dst->context );
357	// when __cfactx_switch returns we are back in the processor coroutine
358
359	/* 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 );
360	/* 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 );
361	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
362
363
364	// We just finished running a thread, there are a few things that could have happened.
365	// 1 - Regular case : the thread has blocked and now one has scheduled it yet.
366	// 2 - Racy case : the thread has blocked but someone has already tried to schedule it.
367	// 3 - Polite Racy case : the thread has blocked, someone has already tried to schedule it, but the thread is nice and wants to go through the ready-queue any way
368	// 4 - Preempted
369	// In case 1, we may have won a race so we can't write to the state again.
370	// In case 2, we lost the race so we now own the thread.
371	// In case 3, we lost the race but can just reschedule the thread.
372
373	if(unlikely(thrd_dst->preempted != __NO_PREEMPTION)) {
374	// The thread was preempted, reschedule it and reset the flag
375	__schedule_thread( thrd_dst );
376	break RUNNING;
377	}
378
379	// set state of processor coroutine to active and the thread to inactive
380	static_assert(sizeof(thrd_dst->state) == sizeof(int));
381	enum coroutine_state old_state = __atomic_exchange_n(&thrd_dst->state, Inactive, __ATOMIC_SEQ_CST);
382	switch(old_state) {
383	case Halted:
384	// The thread has halted, it should never be scheduled/run again, leave it back to Halted and move on
385	thrd_dst->state = Halted;
386
387	// We may need to wake someone up here since
388	unpark( this->destroyer __cfaabi_dbg_ctx2 );
389	this->destroyer = 0p;
390	break RUNNING;
391	case Active:
392	// This is case 1, the regular case, nothing more is needed
393	break RUNNING;
394	case Rerun:
395	// This is case 2, the racy case, someone tried to run this thread before it finished blocking
396	// In this case, just run it again.
397	continue RUNNING;
398	default:
399	// This makes no sense, something is wrong abort
400	abort("Finished running a thread that was Inactive/Start/Primed %d\n", old_state);
401	}
402	}
403
404	// Just before returning to the processor, set the processor coroutine to active
405	proc_cor->state = Active;
406	}
407
408	// KERNEL_ONLY
409	void returnToKernel() {
410	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
411	$coroutine * proc_cor = get_coroutine(kernelTLS.this_processor->runner);
412	$thread * thrd_src = kernelTLS.this_thread;
413
414	// Run the thread on this processor
415	{
416	int local_errno = *__volatile_errno();
417	#if defined( __i386 ) \|\| defined( __x86_64 )
418	__x87_store;
419	#endif
420	verify( proc_cor->context.SP );
421	__cfactx_switch( &thrd_src->context, &proc_cor->context );
422	#if defined( __i386 ) \|\| defined( __x86_64 )
423	__x87_load;
424	#endif
425	*__volatile_errno() = local_errno;
426	}
427
428	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
429	/* 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 );
430	/* 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 );
431	}
432
433	// KERNEL_ONLY
434	// Context invoker for processors
435	// This is the entry point for processors (kernel threads)
436	// It effectively constructs a coroutine by stealing the pthread stack
437	static void * __invoke_processor(void * arg) {
438	processor * proc = (processor *) arg;
439	kernelTLS.this_processor = proc;
440	kernelTLS.this_thread = 0p;
441	kernelTLS.preemption_state.[enabled, disable_count] = [false, 1];
442	// SKULLDUGGERY: We want to create a context for the processor coroutine
443	// which is needed for the 2-step context switch. However, there is no reason
444	// to waste the perfectly valid stack create by pthread.
445	current_stack_info_t info;
446	__stack_t ctx;
447	info.storage = &ctx;
448	(proc->runner){ proc, &info };
449
450	__cfaabi_dbg_print_safe("Coroutine : created stack %p\n", get_coroutine(proc->runner)->stack.storage);
451
452	//Set global state
453	kernelTLS.this_thread = 0p;
454
455	//We now have a proper context from which to schedule threads
456	__cfaabi_dbg_print_safe("Kernel : core %p created (%p, %p)\n", proc, &proc->runner, &ctx);
457
458	// SKULLDUGGERY: Since the coroutine doesn't have its own stack, we can't
459	// resume it to start it like it normally would, it will just context switch
460	// back to here. Instead directly call the main since we already are on the
461	// appropriate stack.
462	get_coroutine(proc->runner)->state = Active;
463	main( proc->runner );
464	get_coroutine(proc->runner)->state = Halted;
465
466	// Main routine of the core returned, the core is now fully terminated
467	__cfaabi_dbg_print_safe("Kernel : core %p main ended (%p)\n", proc, &proc->runner);
468
469	return 0p;
470	}
471
472	static void Abort( int ret, const char func[] ) {
473	if ( ret ) { // pthread routines return errno values
474	abort( "%s : internal error, error(%d) %s.", func, ret, strerror( ret ) );
475	} // if
476	} // Abort
477
478	void * __create_pthread( pthread_t * pthread, void * (start)(void ), void * arg ) {
479	pthread_attr_t attr;
480
481	Abort( pthread_attr_init( &attr ), "pthread_attr_init" ); // initialize attribute
482
483	size_t stacksize;
484	// default stack size, normally defined by shell limit
485	Abort( pthread_attr_getstacksize( &attr, &stacksize ), "pthread_attr_getstacksize" );
486	assert( stacksize >= PTHREAD_STACK_MIN );
487
488	void * stack;
489	__cfaabi_dbg_debug_do(
490	stack = memalign( __page_size, stacksize + __page_size );
491	// pthread has no mechanism to create the guard page in user supplied stack.
492	if ( mprotect( stack, __page_size, PROT_NONE ) == -1 ) {
493	abort( "mprotect : internal error, mprotect failure, error(%d) %s.", errno, strerror( errno ) );
494	} // if
495	);
496	__cfaabi_dbg_no_debug_do(
497	stack = malloc( stacksize );
498	);
499
500	Abort( pthread_attr_setstack( &attr, stack, stacksize ), "pthread_attr_setstack" );
501
502	Abort( pthread_create( pthread, &attr, start, arg ), "pthread_create" );
503	return stack;
504	}
505
506	// KERNEL_ONLY
507	static void __kernel_first_resume( processor * this ) {
508	$thread * src = mainThread;
509	$coroutine * dst = get_coroutine(this->runner);
510
511	verify( ! kernelTLS.preemption_state.enabled );
512
513	kernelTLS.this_thread->curr_cor = dst;
514	__stack_prepare( &dst->stack, 65000 );
515	__cfactx_start(main, dst, this->runner, __cfactx_invoke_coroutine);
516
517	verify( ! kernelTLS.preemption_state.enabled );
518
519	dst->last = &src->self_cor;
520	dst->starter = dst->starter ? dst->starter : &src->self_cor;
521
522	// set state of current coroutine to inactive
523	src->state = src->state == Halted ? Halted : Inactive;
524
525	// context switch to specified coroutine
526	verify( dst->context.SP );
527	__cfactx_switch( &src->context, &dst->context );
528	// when __cfactx_switch returns we are back in the src coroutine
529
530	mainThread->curr_cor = &mainThread->self_cor;
531
532	// set state of new coroutine to active
533	src->state = Active;
534
535	verify( ! kernelTLS.preemption_state.enabled );
536	}
537
538	// KERNEL_ONLY
539	static void __kernel_last_resume( processor * this ) {
540	$coroutine * src = &mainThread->self_cor;
541	$coroutine * dst = get_coroutine(this->runner);
542
543	verify( ! kernelTLS.preemption_state.enabled );
544	verify( dst->starter == src );
545	verify( dst->context.SP );
546
547	// context switch to the processor
548	__cfactx_switch( &src->context, &dst->context );
549	}
550
551	//-----------------------------------------------------------------------------
552	// Scheduler routines
553	// KERNEL ONLY
554	void __schedule_thread( $thread * thrd ) with( *thrd->curr_cluster ) {
555	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
556	/* paranoid */ #if defined( __CFA_WITH_VERIFY__ )
557	/* paranoid */ if( thrd->state == Inactive \|\| thrd->state == Start ) assertf( thrd->preempted == __NO_PREEMPTION,
558	"Error inactive thread marked as preempted, state %d, preemption %d\n", thrd->state, thrd->preempted );
559	/* paranoid */ if( thrd->preempted != __NO_PREEMPTION ) assertf(thrd->state == Active \|\| thrd->state == Rerun,
560	"Error preempted thread marked as not currently running, state %d, preemption %d\n", thrd->state, thrd->preempted );
561	/* paranoid */ #endif
562	/* paranoid */ verifyf( thrd->next == 0p, "Expected null got %p", thrd->next );
563
564	lock ( ready_queue_lock __cfaabi_dbg_ctx2 );
565	bool was_empty = !(ready_queue != 0);
566	append( ready_queue, thrd );
567	unlock( ready_queue_lock );
568
569	if(was_empty) {
570	lock (proc_list_lock __cfaabi_dbg_ctx2);
571	if(idles) {
572	wake_fast(idles.head);
573	}
574	unlock (proc_list_lock);
575	}
576	else if( struct processor * idle = idles.head ) {
577	wake_fast(idle);
578	}
579
580	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
581	}
582
583	// KERNEL ONLY
584	static $thread * __next_thread(cluster * this) with( *this ) {
585	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
586
587	lock( ready_queue_lock __cfaabi_dbg_ctx2 );
588	$thread * head = pop_head( ready_queue );
589	unlock( ready_queue_lock );
590
591	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
592	return head;
593	}
594
595	void unpark( $thread * thrd __cfaabi_dbg_ctx_param2 ) {
596	if( !thrd ) return;
597
598	disable_interrupts();
599	static_assert(sizeof(thrd->state) == sizeof(int));
600
601	// record activity
602	__cfaabi_dbg_record_thrd( *thrd, false, caller );
603
604	enum coroutine_state old_state = __atomic_exchange_n(&thrd->state, Rerun, __ATOMIC_SEQ_CST);
605	switch(old_state) {
606	case Active:
607	// Wake won the race, the thread will reschedule/rerun itself
608	break;
609	case Inactive:
610	/* paranoid */ verify( ! thrd->preempted != __NO_PREEMPTION );
611
612	// Wake lost the race,
613	thrd->state = Inactive;
614	__schedule_thread( thrd );
615	break;
616	case Rerun:
617	abort("More than one thread attempted to schedule thread %p\n", thrd);
618	break;
619	case Halted:
620	case Start:
621	case Primed:
622	default:
623	// This makes no sense, something is wrong abort
624	abort();
625	}
626	enable_interrupts( __cfaabi_dbg_ctx );
627	}
628
629	void park( __cfaabi_dbg_ctx_param ) {
630	/* paranoid */ verify( kernelTLS.preemption_state.enabled );
631	disable_interrupts();
632	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
633	/* paranoid */ verify( kernelTLS.this_thread->preempted == __NO_PREEMPTION );
634
635	// record activity
636	__cfaabi_dbg_record_thrd( *kernelTLS.this_thread, true, caller );
637
638	returnToKernel();
639
640	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
641	enable_interrupts( __cfaabi_dbg_ctx );
642	/* paranoid */ verify( kernelTLS.preemption_state.enabled );
643
644	}
645
646	// KERNEL ONLY
647	void __leave_thread() {
648	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
649	returnToKernel();
650	abort();
651	}
652
653	// KERNEL ONLY
654	bool force_yield( __Preemption_Reason reason ) {
655	/* paranoid */ verify( kernelTLS.preemption_state.enabled );
656	disable_interrupts();
657	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
658
659	$thread * thrd = kernelTLS.this_thread;
660	/* paranoid */ verify(thrd->state == Active \|\| thrd->state == Rerun);
661
662	// SKULLDUGGERY: It is possible that we are preempting this thread just before
663	// it was going to park itself. If that is the case and it is already using the
664	// intrusive fields then we can't use them to preempt the thread
665	// If that is the case, abandon the preemption.
666	bool preempted = false;
667	if(thrd->next == 0p) {
668	preempted = true;
669	thrd->preempted = reason;
670	returnToKernel();
671	}
672
673	/* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
674	enable_interrupts_noPoll();
675	/* paranoid */ verify( kernelTLS.preemption_state.enabled );
676
677	return preempted;
678	}
679
680	//=============================================================================================
681	// Kernel Setup logic
682	//=============================================================================================
683	//-----------------------------------------------------------------------------
684	// Kernel boot procedures
685	static void __kernel_startup(void) {
686	verify( ! kernelTLS.preemption_state.enabled );
687	__cfaabi_dbg_print_safe("Kernel : Starting\n");
688
689	__page_size = sysconf( _SC_PAGESIZE );
690
691	__cfa_dbg_global_clusters.list{ __get };
692	__cfa_dbg_global_clusters.lock{};
693
694	// Initialize the main cluster
695	mainCluster = (cluster *)&storage_mainCluster;
696	(*mainCluster){"Main Cluster"};
697
698	__cfaabi_dbg_print_safe("Kernel : Main cluster ready\n");
699
700	// Start by initializing the main thread
701	// SKULLDUGGERY: the mainThread steals the process main thread
702	// which will then be scheduled by the mainProcessor normally
703	mainThread = ($thread *)&storage_mainThread;
704	current_stack_info_t info;
705	info.storage = (__stack_t*)&storage_mainThreadCtx;
706	(*mainThread){ &info };
707
708	__cfaabi_dbg_print_safe("Kernel : Main thread ready\n");
709
710
711
712	// Construct the processor context of the main processor
713	void ?{}(processorCtx_t & this, processor * proc) {
714	(this.__cor){ "Processor" };
715	this.__cor.starter = 0p;
716	this.proc = proc;
717	}
718
719	void ?{}(processor & this) with( this ) {
720	name = "Main Processor";
721	cltr = mainCluster;
722	terminated{ 0 };
723	do_terminate = false;
724	preemption_alarm = 0p;
725	pending_preemption = false;
726	kernel_thread = pthread_self();
727
728	runner{ &this };
729	__cfaabi_dbg_print_safe("Kernel : constructed main processor context %p\n", &runner);
730	}
731
732	// Initialize the main processor and the main processor ctx
733	// (the coroutine that contains the processing control flow)
734	mainProcessor = (processor *)&storage_mainProcessor;
735	(*mainProcessor){};
736
737	//initialize the global state variables
738	kernelTLS.this_processor = mainProcessor;
739	kernelTLS.this_thread = mainThread;
740
741	// Enable preemption
742	kernel_start_preemption();
743
744	// Add the main thread to the ready queue
745	// once resume is called on mainProcessor->runner the mainThread needs to be scheduled like any normal thread
746	__schedule_thread(mainThread);
747
748	// SKULLDUGGERY: Force a context switch to the main processor to set the main thread's context to the current UNIX
749	// context. Hence, the main thread does not begin through __cfactx_invoke_thread, like all other threads. The trick here is that
750	// mainThread is on the ready queue when this call is made.
751	__kernel_first_resume( kernelTLS.this_processor );
752
753
754
755	// THE SYSTEM IS NOW COMPLETELY RUNNING
756	__cfaabi_dbg_print_safe("Kernel : Started\n--------------------------------------------------\n\n");
757
758	verify( ! kernelTLS.preemption_state.enabled );
759	enable_interrupts( __cfaabi_dbg_ctx );
760	verify( TL_GET( preemption_state.enabled ) );
761	}
762
763	static void __kernel_shutdown(void) {
764	__cfaabi_dbg_print_safe("\n--------------------------------------------------\nKernel : Shutting down\n");
765
766	verify( TL_GET( preemption_state.enabled ) );
767	disable_interrupts();
768	verify( ! kernelTLS.preemption_state.enabled );
769
770	// SKULLDUGGERY: Notify the mainProcessor it needs to terminates.
771	// When its coroutine terminates, it return control to the mainThread
772	// which is currently here
773	__atomic_store_n(&mainProcessor->do_terminate, true, __ATOMIC_RELEASE);
774	__kernel_last_resume( kernelTLS.this_processor );
775	mainThread->self_cor.state = Halted;
776
777	// THE SYSTEM IS NOW COMPLETELY STOPPED
778
779	// Disable preemption
780	kernel_stop_preemption();
781
782	// Destroy the main processor and its context in reverse order of construction
783	// These were manually constructed so we need manually destroy them
784	^(*mainProcessor){};
785
786	// Final step, destroy the main thread since it is no longer needed
787	// Since we provided a stack to this taxk it will not destroy anything
788	/* paranoid / verify(mainThread->self_cor.stack.storage == (__stack_t)(((uintptr_t)&storage_mainThreadCtx)\| 0x1));
789	^(*mainThread){};
790
791	^(__cfa_dbg_global_clusters.list){};
792	^(__cfa_dbg_global_clusters.lock){};
793
794	__cfaabi_dbg_print_safe("Kernel : Shutdown complete\n");
795	}
796
797	//=============================================================================================
798	// Kernel Quiescing
799	//=============================================================================================
800	static void __halt(processor * this) with( *this ) {
801	// verify( ! __atomic_load_n(&do_terminate, __ATOMIC_SEQ_CST) );
802
803	with( *cltr ) {
804	lock (proc_list_lock __cfaabi_dbg_ctx2);
805	remove (procs, *this);
806	push_front(idles, *this);
807	unlock (proc_list_lock);
808	}
809
810	__cfaabi_dbg_print_safe("Kernel : Processor %p ready to sleep\n", this);
811
812	wait( idleLock );
813
814	__cfaabi_dbg_print_safe("Kernel : Processor %p woke up and ready to run\n", this);
815
816	with( *cltr ) {
817	lock (proc_list_lock __cfaabi_dbg_ctx2);
818	remove (idles, *this);
819	push_front(procs, *this);
820	unlock (proc_list_lock);
821	}
822	}
823
824	//=============================================================================================
825	// Unexpected Terminating logic
826	//=============================================================================================
827	static __spinlock_t kernel_abort_lock;
828	static bool kernel_abort_called = false;
829
830	void * kernel_abort(void) __attribute__ ((__nothrow__)) {
831	// abort cannot be recursively entered by the same or different processors because all signal handlers return when
832	// the globalAbort flag is true.
833	lock( kernel_abort_lock __cfaabi_dbg_ctx2 );
834
835	// first task to abort ?
836	if ( kernel_abort_called ) { // not first task to abort ?
837	unlock( kernel_abort_lock );
838
839	sigset_t mask;
840	sigemptyset( &mask );
841	sigaddset( &mask, SIGALRM ); // block SIGALRM signals
842	sigaddset( &mask, SIGUSR1 ); // block SIGALRM signals
843	sigsuspend( &mask ); // block the processor to prevent further damage during abort
844	_exit( EXIT_FAILURE ); // if processor unblocks before it is killed, terminate it
845	}
846	else {
847	kernel_abort_called = true;
848	unlock( kernel_abort_lock );
849	}
850
851	return kernelTLS.this_thread;
852	}
853
854	void kernel_abort_msg( void * kernel_data, char * abort_text, int abort_text_size ) {
855	$thread * thrd = kernel_data;
856
857	if(thrd) {
858	int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
859	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
860
861	if ( &thrd->self_cor != thrd->curr_cor ) {
862	len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
863	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
864	}
865	else {
866	__cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
867	}
868	}
869	else {
870	int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
871	__cfaabi_bits_write( STDERR_FILENO, abort_text, len );
872	}
873	}
874
875	int kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
876	return get_coroutine(kernelTLS.this_thread) == get_coroutine(mainThread) ? 4 : 2;
877	}
878
879	static __spinlock_t kernel_debug_lock;
880
881	extern "C" {
882	void __cfaabi_bits_acquire() {
883	lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
884	}
885
886	void __cfaabi_bits_release() {
887	unlock( kernel_debug_lock );
888	}
889	}
890
891	//=============================================================================================
892	// Kernel Utilities
893	//=============================================================================================
894	//-----------------------------------------------------------------------------
895	// Locks
896	void ?{}( semaphore & this, int count = 1 ) {
897	(this.lock){};
898	this.count = count;
899	(this.waiting){};
900	}
901	void ^?{}(semaphore & this) {}
902
903	void P(semaphore & this) with( this ){
904	lock( lock __cfaabi_dbg_ctx2 );
905	count -= 1;
906	if ( count < 0 ) {
907	// queue current task
908	append( waiting, kernelTLS.this_thread );
909
910	// atomically release spin lock and block
911	unlock( lock );
912	park( __cfaabi_dbg_ctx );
913	}
914	else {
915	unlock( lock );
916	}
917	}
918
919	void V(semaphore & this) with( this ) {
920	$thread * thrd = 0p;
921	lock( lock __cfaabi_dbg_ctx2 );
922	count += 1;
923	if ( count <= 0 ) {
924	// remove task at head of waiting list
925	thrd = pop_head( waiting );
926	}
927
928	unlock( lock );
929
930	// make new owner
931	unpark( thrd __cfaabi_dbg_ctx2 );
932	}
933
934	//-----------------------------------------------------------------------------
935	// Global Queues
936	void doregister( cluster & cltr ) {
937	lock ( __cfa_dbg_global_clusters.lock __cfaabi_dbg_ctx2);
938	push_front( __cfa_dbg_global_clusters.list, cltr );
939	unlock ( __cfa_dbg_global_clusters.lock );
940	}
941
942	void unregister( cluster & cltr ) {
943	lock ( __cfa_dbg_global_clusters.lock __cfaabi_dbg_ctx2);
944	remove( __cfa_dbg_global_clusters.list, cltr );
945	unlock( __cfa_dbg_global_clusters.lock );
946	}
947
948	void doregister( cluster * cltr, $thread & thrd ) {
949	lock (cltr->thread_list_lock __cfaabi_dbg_ctx2);
950	cltr->nthreads += 1;
951	push_front(cltr->threads, thrd);
952	unlock (cltr->thread_list_lock);
953	}
954
955	void unregister( cluster * cltr, $thread & thrd ) {
956	lock (cltr->thread_list_lock __cfaabi_dbg_ctx2);
957	remove(cltr->threads, thrd );
958	cltr->nthreads -= 1;
959	unlock(cltr->thread_list_lock);
960	}
961
962	void doregister( cluster * cltr, processor * proc ) {
963	lock (cltr->proc_list_lock __cfaabi_dbg_ctx2);
964	cltr->nprocessors += 1;
965	push_front(cltr->procs, *proc);
966	unlock (cltr->proc_list_lock);
967	}
968
969	void unregister( cluster * cltr, processor * proc ) {
970	lock (cltr->proc_list_lock __cfaabi_dbg_ctx2);
971	remove(cltr->procs, *proc );
972	cltr->nprocessors -= 1;
973	unlock(cltr->proc_list_lock);
974	}
975
976	//-----------------------------------------------------------------------------
977	// Debug
978	__cfaabi_dbg_debug_do(
979	extern "C" {
980	void __cfaabi_dbg_record_lock(__spinlock_t & this, const char prev_name[]) {
981	this.prev_name = prev_name;
982	this.prev_thrd = kernelTLS.this_thread;
983	}
984
985	void __cfaabi_dbg_record_thrd($thread & this, bool park, const char prev_name[]) {
986	if(park) {
987	this.prev_park = prev_name;
988	this.park_stale = false;
989	}
990	else {
991	this.prev_unpark = prev_name;
992	this.unpark_stale = false;
993	}
994	}
995	}
996	)
997
998	//-----------------------------------------------------------------------------
999	// Debug
1000	bool threading_enabled(void) __attribute__((const)) {
1001	return true;
1002	}
1003	// Local Variables: //
1004	// mode: c //
1005	// tab-width: 4 //
1006	// End: //

Note: See TracBrowser for help on using the repository browser.

Download in other formats:

Original Format