source: libcfa/src/concurrency/kernel.cfa @ 5c1a531

arm-ehcleanup-dtorsjacob/cs343-translationjenkins-sandboxnew-astnew-ast-unique-expr
Last change on this file since 5c1a531 was 5c1a531, checked in by tdelisle <tdelisle@…>, 3 years ago

Fixed errno virtualization and enabled preemption during coroutine context switch

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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 : Mon Apr  9 16:11:46 2018
13// Update Count     : 24
14//
15
16//C Includes
17#include <stddef.h>
18#include <errno.h>
19#include <string.h>
20extern "C" {
21#include <stdio.h>
22#include <fenv.h>
23#include <sys/resource.h>
24#include <signal.h>
25#include <unistd.h>
26}
27
28//CFA Includes
29#include "time.hfa"
30#include "kernel_private.hfa"
31#include "preemption.hfa"
32#include "startup.hfa"
33
34//Private includes
35#define __CFA_INVOKE_PRIVATE__
36#include "invoke.h"
37
38//Start and stop routine for the kernel, declared first to make sure they run first
39static void kernel_startup(void)  __attribute__(( constructor( STARTUP_PRIORITY_KERNEL ) ));
40static void kernel_shutdown(void) __attribute__(( destructor ( STARTUP_PRIORITY_KERNEL ) ));
41
42//-----------------------------------------------------------------------------
43// Kernel storage
44KERNEL_STORAGE(cluster,         mainCluster);
45KERNEL_STORAGE(processor,       mainProcessor);
46KERNEL_STORAGE(thread_desc,     mainThread);
47KERNEL_STORAGE(__stack_t,       mainThreadCtx);
48
49cluster     * mainCluster;
50processor   * mainProcessor;
51thread_desc * mainThread;
52
53extern "C" {
54struct { __dllist_t(cluster) list; __spinlock_t lock; } __cfa_dbg_global_clusters;
55}
56
57size_t __page_size = 0;
58
59//-----------------------------------------------------------------------------
60// Global state
61thread_local struct KernelThreadData kernelTLS __attribute__ ((tls_model ( "initial-exec" ))) = {
62        NULL,
63        NULL,
64        { 1, false, false }
65};
66
67//-----------------------------------------------------------------------------
68// Struct to steal stack
69struct current_stack_info_t {
70        __stack_t * storage;            // pointer to stack object
71        void *base;                             // base of stack
72        void *limit;                    // stack grows towards stack limit
73        void *context;                  // address of cfa_context_t
74};
75
76void ?{}( current_stack_info_t & this ) {
77        __stack_context_t ctx;
78        CtxGet( ctx );
79        this.base = ctx.FP;
80
81        rlimit r;
82        getrlimit( RLIMIT_STACK, &r);
83        size_t size = r.rlim_cur;
84
85        this.limit = (void *)(((intptr_t)this.base) - size);
86        this.context = &storage_mainThreadCtx;
87}
88
89//-----------------------------------------------------------------------------
90// Main thread construction
91
92void ?{}( coroutine_desc & this, current_stack_info_t * info) with( this ) {
93        stack.storage = info->storage;
94        with(*stack.storage) {
95                limit     = info->limit;
96                base      = info->base;
97        }
98        *((intptr_t*)&stack.storage) |= 0x1;
99        name = "Main Thread";
100        state = Start;
101        starter = NULL;
102        last = NULL;
103        cancellation = NULL;
104}
105
106void ?{}( thread_desc & this, current_stack_info_t * info) with( this ) {
107        state = Start;
108        self_cor{ info };
109        curr_cor = &self_cor;
110        curr_cluster = mainCluster;
111        self_mon.owner = &this;
112        self_mon.recursion = 1;
113        self_mon_p = &self_mon;
114        next = NULL;
115
116        node.next = NULL;
117        node.prev = NULL;
118        doregister(curr_cluster, this);
119
120        monitors{ &self_mon_p, 1, (fptr_t)0 };
121}
122
123//-----------------------------------------------------------------------------
124// Processor coroutine
125void ?{}(processorCtx_t & this) {
126
127}
128
129// Construct the processor context of non-main processors
130static void ?{}(processorCtx_t & this, processor * proc, current_stack_info_t * info) {
131        (this.__cor){ info };
132        this.proc = proc;
133}
134
135static void start(processor * this);
136void ?{}(processor & this, const char * name, cluster & cltr) with( this ) {
137        this.name = name;
138        this.cltr = &cltr;
139        terminated{ 0 };
140        do_terminate = false;
141        preemption_alarm = NULL;
142        pending_preemption = false;
143        runner.proc = &this;
144
145        idleLock{};
146
147        start( &this );
148}
149
150void ^?{}(processor & this) with( this ){
151        if( ! __atomic_load_n(&do_terminate, __ATOMIC_ACQUIRE) ) {
152                __cfaabi_dbg_print_safe("Kernel : core %p signaling termination\n", &this);
153
154                __atomic_store_n(&do_terminate, true, __ATOMIC_RELAXED);
155                wake( &this );
156
157                P( terminated );
158                verify( kernelTLS.this_processor != &this);
159        }
160
161        pthread_join( kernel_thread, NULL );
162}
163
164void ?{}(cluster & this, const char * name, Duration preemption_rate) with( this ) {
165        this.name = name;
166        this.preemption_rate = preemption_rate;
167        ready_queue{};
168        ready_queue_lock{};
169
170        procs{ __get };
171        idles{ __get };
172        threads{ __get };
173
174        doregister(this);
175}
176
177void ^?{}(cluster & this) {
178        unregister(this);
179}
180
181//=============================================================================================
182// Kernel Scheduling logic
183//=============================================================================================
184static void runThread(processor * this, thread_desc * dst);
185static void finishRunning(processor * this);
186static void halt(processor * this);
187
188//Main of the processor contexts
189void main(processorCtx_t & runner) {
190        processor * this = runner.proc;
191        verify(this);
192
193        __cfaabi_dbg_print_safe("Kernel : core %p starting\n", this);
194
195        doregister(this->cltr, this);
196
197        {
198                // Setup preemption data
199                preemption_scope scope = { this };
200
201                __cfaabi_dbg_print_safe("Kernel : core %p started\n", this);
202
203                thread_desc * readyThread = NULL;
204                for( unsigned int spin_count = 0; ! __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST); spin_count++ )
205                {
206                        readyThread = nextThread( this->cltr );
207
208                        if(readyThread)
209                        {
210                                verify( ! kernelTLS.preemption_state.enabled );
211
212                                runThread(this, readyThread);
213
214                                verify( ! kernelTLS.preemption_state.enabled );
215
216                                //Some actions need to be taken from the kernel
217                                finishRunning(this);
218
219                                spin_count = 0;
220                        }
221                        else
222                        {
223                                // spin(this, &spin_count);
224                                halt(this);
225                        }
226                }
227
228                __cfaabi_dbg_print_safe("Kernel : core %p stopping\n", this);
229        }
230
231        unregister(this->cltr, this);
232
233        V( this->terminated );
234
235        __cfaabi_dbg_print_safe("Kernel : core %p terminated\n", this);
236}
237
238static int * __volatile_errno() __attribute__((noinline));
239static int * __volatile_errno() { asm(""); return &errno; }
240
241// KERNEL ONLY
242// runThread runs a thread by context switching
243// from the processor coroutine to the target thread
244static void runThread(processor * this, thread_desc * thrd_dst) {
245        coroutine_desc * proc_cor = get_coroutine(this->runner);
246
247        // Reset the terminating actions here
248        this->finish.action_code = No_Action;
249
250        // Update global state
251        kernelTLS.this_thread = thrd_dst;
252
253        // set state of processor coroutine to inactive and the thread to active
254        proc_cor->state = proc_cor->state == Halted ? Halted : Inactive;
255        thrd_dst->state = Active;
256
257        // set context switch to the thread that the processor is executing
258        verify( thrd_dst->context.SP );
259        CtxSwitch( &proc_cor->context, &thrd_dst->context );
260        // when CtxSwitch returns we are back in the processor coroutine
261
262        // set state of processor coroutine to active and the thread to inactive
263        thrd_dst->state = thrd_dst->state == Halted ? Halted : Inactive;
264        proc_cor->state = Active;
265}
266
267// KERNEL_ONLY
268static void returnToKernel() {
269        coroutine_desc * proc_cor = get_coroutine(kernelTLS.this_processor->runner);
270        thread_desc * thrd_src = kernelTLS.this_thread;
271
272        // set state of current coroutine to inactive
273        thrd_src->state = thrd_src->state == Halted ? Halted : Inactive;
274        proc_cor->state = Active;
275        int local_errno = *__volatile_errno();
276
277        // set new coroutine that the processor is executing
278        // and context switch to it
279        verify( proc_cor->context.SP );
280        CtxSwitch( &thrd_src->context, &proc_cor->context );
281
282        // set state of new coroutine to active
283        proc_cor->state = proc_cor->state == Halted ? Halted : Inactive;
284        thrd_src->state = Active;
285        *__volatile_errno() = local_errno;
286}
287
288// KERNEL_ONLY
289// Once a thread has finished running, some of
290// its final actions must be executed from the kernel
291static void finishRunning(processor * this) with( this->finish ) {
292        verify( ! kernelTLS.preemption_state.enabled );
293        choose( action_code ) {
294        case No_Action:
295                break;
296        case Release:
297                unlock( *lock );
298        case Schedule:
299                ScheduleThread( thrd );
300        case Release_Schedule:
301                unlock( *lock );
302                ScheduleThread( thrd );
303        case Release_Multi:
304                for(int i = 0; i < lock_count; i++) {
305                        unlock( *locks[i] );
306                }
307        case Release_Multi_Schedule:
308                for(int i = 0; i < lock_count; i++) {
309                        unlock( *locks[i] );
310                }
311                for(int i = 0; i < thrd_count; i++) {
312                        ScheduleThread( thrds[i] );
313                }
314        case Callback:
315                callback();
316        default:
317                abort("KERNEL ERROR: Unexpected action to run after thread");
318        }
319}
320
321// KERNEL_ONLY
322// Context invoker for processors
323// This is the entry point for processors (kernel threads)
324// It effectively constructs a coroutine by stealing the pthread stack
325static void * CtxInvokeProcessor(void * arg) {
326        processor * proc = (processor *) arg;
327        kernelTLS.this_processor = proc;
328        kernelTLS.this_thread    = NULL;
329        kernelTLS.preemption_state.[enabled, disable_count] = [false, 1];
330        // SKULLDUGGERY: We want to create a context for the processor coroutine
331        // which is needed for the 2-step context switch. However, there is no reason
332        // to waste the perfectly valid stack create by pthread.
333        current_stack_info_t info;
334        __stack_t ctx;
335        info.storage = &ctx;
336        (proc->runner){ proc, &info };
337
338        __cfaabi_dbg_print_safe("Coroutine : created stack %p\n", get_coroutine(proc->runner)->stack.storage);
339
340        //Set global state
341        kernelTLS.this_thread    = NULL;
342
343        //We now have a proper context from which to schedule threads
344        __cfaabi_dbg_print_safe("Kernel : core %p created (%p, %p)\n", proc, &proc->runner, &ctx);
345
346        // SKULLDUGGERY: Since the coroutine doesn't have its own stack, we can't
347        // resume it to start it like it normally would, it will just context switch
348        // back to here. Instead directly call the main since we already are on the
349        // appropriate stack.
350        get_coroutine(proc->runner)->state = Active;
351        main( proc->runner );
352        get_coroutine(proc->runner)->state = Halted;
353
354        // Main routine of the core returned, the core is now fully terminated
355        __cfaabi_dbg_print_safe("Kernel : core %p main ended (%p)\n", proc, &proc->runner);
356
357        return NULL;
358}
359
360static void start(processor * this) {
361        __cfaabi_dbg_print_safe("Kernel : Starting core %p\n", this);
362
363        pthread_create( &this->kernel_thread, NULL, CtxInvokeProcessor, (void*)this );
364
365        __cfaabi_dbg_print_safe("Kernel : core %p started\n", this);
366}
367
368// KERNEL_ONLY
369void kernel_first_resume( processor * this ) {
370        thread_desc * src = mainThread;
371        coroutine_desc * dst = get_coroutine(this->runner);
372
373        verify( ! kernelTLS.preemption_state.enabled );
374
375        __stack_prepare( &dst->stack, 65000 );
376        CtxStart(&this->runner, CtxInvokeCoroutine);
377
378        verify( ! kernelTLS.preemption_state.enabled );
379
380        dst->last = &src->self_cor;
381        dst->starter = dst->starter ? dst->starter : &src->self_cor;
382
383        // set state of current coroutine to inactive
384        src->state = src->state == Halted ? Halted : Inactive;
385
386        // context switch to specified coroutine
387        verify( dst->context.SP );
388        CtxSwitch( &src->context, &dst->context );
389        // when CtxSwitch returns we are back in the src coroutine
390
391        // set state of new coroutine to active
392        src->state = Active;
393
394        verify( ! kernelTLS.preemption_state.enabled );
395}
396
397// KERNEL_ONLY
398void kernel_last_resume( processor * this ) {
399        coroutine_desc * src = &mainThread->self_cor;
400        coroutine_desc * dst = get_coroutine(this->runner);
401
402        verify( ! kernelTLS.preemption_state.enabled );
403        verify( dst->starter == src );
404        verify( dst->context.SP );
405
406        // context switch to the processor
407        CtxSwitch( &src->context, &dst->context );
408}
409
410//-----------------------------------------------------------------------------
411// Scheduler routines
412
413// KERNEL ONLY
414void ScheduleThread( thread_desc * thrd ) {
415        verify( thrd );
416        verify( thrd->state != Halted );
417
418        verify( ! kernelTLS.preemption_state.enabled );
419
420        verifyf( thrd->next == NULL, "Expected null got %p", thrd->next );
421
422        with( *thrd->curr_cluster ) {
423                lock  ( ready_queue_lock __cfaabi_dbg_ctx2 );
424                bool was_empty = !(ready_queue != 0);
425                append( ready_queue, thrd );
426                unlock( ready_queue_lock );
427
428                if(was_empty) {
429                        lock      (proc_list_lock __cfaabi_dbg_ctx2);
430                        if(idles) {
431                                wake_fast(idles.head);
432                        }
433                        unlock    (proc_list_lock);
434                }
435                else if( struct processor * idle = idles.head ) {
436                        wake_fast(idle);
437                }
438
439        }
440
441        verify( ! kernelTLS.preemption_state.enabled );
442}
443
444// KERNEL ONLY
445thread_desc * nextThread(cluster * this) with( *this ) {
446        verify( ! kernelTLS.preemption_state.enabled );
447        lock( ready_queue_lock __cfaabi_dbg_ctx2 );
448        thread_desc * head = pop_head( ready_queue );
449        unlock( ready_queue_lock );
450        verify( ! kernelTLS.preemption_state.enabled );
451        return head;
452}
453
454void BlockInternal() {
455        disable_interrupts();
456        verify( ! kernelTLS.preemption_state.enabled );
457        returnToKernel();
458        verify( ! kernelTLS.preemption_state.enabled );
459        enable_interrupts( __cfaabi_dbg_ctx );
460}
461
462void BlockInternal( __spinlock_t * lock ) {
463        disable_interrupts();
464        with( *kernelTLS.this_processor ) {
465                finish.action_code = Release;
466                finish.lock        = lock;
467        }
468
469        verify( ! kernelTLS.preemption_state.enabled );
470        returnToKernel();
471        verify( ! kernelTLS.preemption_state.enabled );
472
473        enable_interrupts( __cfaabi_dbg_ctx );
474}
475
476void BlockInternal( thread_desc * thrd ) {
477        disable_interrupts();
478        with( * kernelTLS.this_processor ) {
479                finish.action_code = Schedule;
480                finish.thrd        = thrd;
481        }
482
483        verify( ! kernelTLS.preemption_state.enabled );
484        returnToKernel();
485        verify( ! kernelTLS.preemption_state.enabled );
486
487        enable_interrupts( __cfaabi_dbg_ctx );
488}
489
490void BlockInternal( __spinlock_t * lock, thread_desc * thrd ) {
491        assert(thrd);
492        disable_interrupts();
493        with( * kernelTLS.this_processor ) {
494                finish.action_code = Release_Schedule;
495                finish.lock        = lock;
496                finish.thrd        = thrd;
497        }
498
499        verify( ! kernelTLS.preemption_state.enabled );
500        returnToKernel();
501        verify( ! kernelTLS.preemption_state.enabled );
502
503        enable_interrupts( __cfaabi_dbg_ctx );
504}
505
506void BlockInternal(__spinlock_t * locks [], unsigned short count) {
507        disable_interrupts();
508        with( * kernelTLS.this_processor ) {
509                finish.action_code = Release_Multi;
510                finish.locks       = locks;
511                finish.lock_count  = count;
512        }
513
514        verify( ! kernelTLS.preemption_state.enabled );
515        returnToKernel();
516        verify( ! kernelTLS.preemption_state.enabled );
517
518        enable_interrupts( __cfaabi_dbg_ctx );
519}
520
521void BlockInternal(__spinlock_t * locks [], unsigned short lock_count, thread_desc * thrds [], unsigned short thrd_count) {
522        disable_interrupts();
523        with( *kernelTLS.this_processor ) {
524                finish.action_code = Release_Multi_Schedule;
525                finish.locks       = locks;
526                finish.lock_count  = lock_count;
527                finish.thrds       = thrds;
528                finish.thrd_count  = thrd_count;
529        }
530
531        verify( ! kernelTLS.preemption_state.enabled );
532        returnToKernel();
533        verify( ! kernelTLS.preemption_state.enabled );
534
535        enable_interrupts( __cfaabi_dbg_ctx );
536}
537
538void BlockInternal(__finish_callback_fptr_t callback) {
539        disable_interrupts();
540        with( *kernelTLS.this_processor ) {
541                finish.action_code = Callback;
542                finish.callback    = callback;
543        }
544
545        verify( ! kernelTLS.preemption_state.enabled );
546        returnToKernel();
547        verify( ! kernelTLS.preemption_state.enabled );
548
549        enable_interrupts( __cfaabi_dbg_ctx );
550}
551
552// KERNEL ONLY
553void LeaveThread(__spinlock_t * lock, thread_desc * thrd) {
554        verify( ! kernelTLS.preemption_state.enabled );
555        with( * kernelTLS.this_processor ) {
556                finish.action_code = thrd ? Release_Schedule : Release;
557                finish.lock        = lock;
558                finish.thrd        = thrd;
559        }
560
561        returnToKernel();
562}
563
564//=============================================================================================
565// Kernel Setup logic
566//=============================================================================================
567//-----------------------------------------------------------------------------
568// Kernel boot procedures
569static void kernel_startup(void) {
570        verify( ! kernelTLS.preemption_state.enabled );
571        __cfaabi_dbg_print_safe("Kernel : Starting\n");
572
573        __page_size = sysconf( _SC_PAGESIZE );
574
575        __cfa_dbg_global_clusters.list{ __get };
576        __cfa_dbg_global_clusters.lock{};
577
578        // Initialize the main cluster
579        mainCluster = (cluster *)&storage_mainCluster;
580        (*mainCluster){"Main Cluster"};
581
582        __cfaabi_dbg_print_safe("Kernel : Main cluster ready\n");
583
584        // Start by initializing the main thread
585        // SKULLDUGGERY: the mainThread steals the process main thread
586        // which will then be scheduled by the mainProcessor normally
587        mainThread = (thread_desc *)&storage_mainThread;
588        current_stack_info_t info;
589        info.storage = (__stack_t*)&storage_mainThreadCtx;
590        (*mainThread){ &info };
591
592        __cfaabi_dbg_print_safe("Kernel : Main thread ready\n");
593
594
595
596        // Construct the processor context of the main processor
597        void ?{}(processorCtx_t & this, processor * proc) {
598                (this.__cor){ "Processor" };
599                this.__cor.starter = NULL;
600                this.proc = proc;
601        }
602
603        void ?{}(processor & this) with( this ) {
604                name = "Main Processor";
605                cltr = mainCluster;
606                terminated{ 0 };
607                do_terminate = false;
608                preemption_alarm = NULL;
609                pending_preemption = false;
610                kernel_thread = pthread_self();
611
612                runner{ &this };
613                __cfaabi_dbg_print_safe("Kernel : constructed main processor context %p\n", &runner);
614        }
615
616        // Initialize the main processor and the main processor ctx
617        // (the coroutine that contains the processing control flow)
618        mainProcessor = (processor *)&storage_mainProcessor;
619        (*mainProcessor){};
620
621        //initialize the global state variables
622        kernelTLS.this_processor = mainProcessor;
623        kernelTLS.this_thread    = mainThread;
624
625        // Enable preemption
626        kernel_start_preemption();
627
628        // Add the main thread to the ready queue
629        // once resume is called on mainProcessor->runner the mainThread needs to be scheduled like any normal thread
630        ScheduleThread(mainThread);
631
632        // SKULLDUGGERY: Force a context switch to the main processor to set the main thread's context to the current UNIX
633        // context. Hence, the main thread does not begin through CtxInvokeThread, like all other threads. The trick here is that
634        // mainThread is on the ready queue when this call is made.
635        kernel_first_resume( kernelTLS.this_processor );
636
637
638
639        // THE SYSTEM IS NOW COMPLETELY RUNNING
640        __cfaabi_dbg_print_safe("Kernel : Started\n--------------------------------------------------\n\n");
641
642        verify( ! kernelTLS.preemption_state.enabled );
643        enable_interrupts( __cfaabi_dbg_ctx );
644        verify( TL_GET( preemption_state.enabled ) );
645}
646
647static void kernel_shutdown(void) {
648        __cfaabi_dbg_print_safe("\n--------------------------------------------------\nKernel : Shutting down\n");
649
650        verify( TL_GET( preemption_state.enabled ) );
651        disable_interrupts();
652        verify( ! kernelTLS.preemption_state.enabled );
653
654        // SKULLDUGGERY: Notify the mainProcessor it needs to terminates.
655        // When its coroutine terminates, it return control to the mainThread
656        // which is currently here
657        __atomic_store_n(&mainProcessor->do_terminate, true, __ATOMIC_RELEASE);
658        kernel_last_resume( kernelTLS.this_processor );
659        mainThread->self_cor.state = Halted;
660
661        // THE SYSTEM IS NOW COMPLETELY STOPPED
662
663        // Disable preemption
664        kernel_stop_preemption();
665
666        // Destroy the main processor and its context in reverse order of construction
667        // These were manually constructed so we need manually destroy them
668        ^(mainProcessor->runner){};
669        ^(mainProcessor){};
670
671        // Final step, destroy the main thread since it is no longer needed
672        // Since we provided a stack to this taxk it will not destroy anything
673        ^(mainThread){};
674
675        ^(__cfa_dbg_global_clusters.list){};
676        ^(__cfa_dbg_global_clusters.lock){};
677
678        __cfaabi_dbg_print_safe("Kernel : Shutdown complete\n");
679}
680
681//=============================================================================================
682// Kernel Quiescing
683//=============================================================================================
684static void halt(processor * this) with( *this ) {
685        // verify( ! __atomic_load_n(&do_terminate, __ATOMIC_SEQ_CST) );
686
687        with( *cltr ) {
688                lock      (proc_list_lock __cfaabi_dbg_ctx2);
689                remove    (procs, *this);
690                push_front(idles, *this);
691                unlock    (proc_list_lock);
692        }
693
694        __cfaabi_dbg_print_safe("Kernel : Processor %p ready to sleep\n", this);
695
696        wait( idleLock );
697
698        __cfaabi_dbg_print_safe("Kernel : Processor %p woke up and ready to run\n", this);
699
700        with( *cltr ) {
701                lock      (proc_list_lock __cfaabi_dbg_ctx2);
702                remove    (idles, *this);
703                push_front(procs, *this);
704                unlock    (proc_list_lock);
705        }
706}
707
708//=============================================================================================
709// Unexpected Terminating logic
710//=============================================================================================
711static __spinlock_t kernel_abort_lock;
712static bool kernel_abort_called = false;
713
714void * kernel_abort(void) __attribute__ ((__nothrow__)) {
715        // abort cannot be recursively entered by the same or different processors because all signal handlers return when
716        // the globalAbort flag is true.
717        lock( kernel_abort_lock __cfaabi_dbg_ctx2 );
718
719        // first task to abort ?
720        if ( kernel_abort_called ) {                    // not first task to abort ?
721                unlock( kernel_abort_lock );
722
723                sigset_t mask;
724                sigemptyset( &mask );
725                sigaddset( &mask, SIGALRM );            // block SIGALRM signals
726                sigsuspend( &mask );                    // block the processor to prevent further damage during abort
727                _exit( EXIT_FAILURE );                  // if processor unblocks before it is killed, terminate it
728        }
729        else {
730                kernel_abort_called = true;
731                unlock( kernel_abort_lock );
732        }
733
734        return kernelTLS.this_thread;
735}
736
737void kernel_abort_msg( void * kernel_data, char * abort_text, int abort_text_size ) {
738        thread_desc * thrd = kernel_data;
739
740        if(thrd) {
741                int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
742                __cfaabi_dbg_bits_write( abort_text, len );
743
744                if ( &thrd->self_cor != thrd->curr_cor ) {
745                        len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
746                        __cfaabi_dbg_bits_write( abort_text, len );
747                }
748                else {
749                        __cfaabi_dbg_bits_write( ".\n", 2 );
750                }
751        }
752        else {
753                int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
754                __cfaabi_dbg_bits_write( abort_text, len );
755        }
756}
757
758int kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
759        return get_coroutine(kernelTLS.this_thread) == get_coroutine(mainThread) ? 4 : 2;
760}
761
762static __spinlock_t kernel_debug_lock;
763
764extern "C" {
765        void __cfaabi_dbg_bits_acquire() {
766                lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
767        }
768
769        void __cfaabi_dbg_bits_release() {
770                unlock( kernel_debug_lock );
771        }
772}
773
774//=============================================================================================
775// Kernel Utilities
776//=============================================================================================
777//-----------------------------------------------------------------------------
778// Locks
779void  ?{}( semaphore & this, int count = 1 ) {
780        (this.lock){};
781        this.count = count;
782        (this.waiting){};
783}
784void ^?{}(semaphore & this) {}
785
786void P(semaphore & this) with( this ){
787        lock( lock __cfaabi_dbg_ctx2 );
788        count -= 1;
789        if ( count < 0 ) {
790                // queue current task
791                append( waiting, kernelTLS.this_thread );
792
793                // atomically release spin lock and block
794                BlockInternal( &lock );
795        }
796        else {
797            unlock( lock );
798        }
799}
800
801void V(semaphore & this) with( this ) {
802        thread_desc * thrd = NULL;
803        lock( lock __cfaabi_dbg_ctx2 );
804        count += 1;
805        if ( count <= 0 ) {
806                // remove task at head of waiting list
807                thrd = pop_head( waiting );
808        }
809
810        unlock( lock );
811
812        // make new owner
813        WakeThread( thrd );
814}
815
816//-----------------------------------------------------------------------------
817// Global Queues
818void doregister( cluster     & cltr ) {
819        lock      ( __cfa_dbg_global_clusters.lock __cfaabi_dbg_ctx2);
820        push_front( __cfa_dbg_global_clusters.list, cltr );
821        unlock    ( __cfa_dbg_global_clusters.lock );
822}
823
824void unregister( cluster     & cltr ) {
825        lock  ( __cfa_dbg_global_clusters.lock __cfaabi_dbg_ctx2);
826        remove( __cfa_dbg_global_clusters.list, cltr );
827        unlock( __cfa_dbg_global_clusters.lock );
828}
829
830void doregister( cluster * cltr, thread_desc & thrd ) {
831        lock      (cltr->thread_list_lock __cfaabi_dbg_ctx2);
832        push_front(cltr->threads, thrd);
833        unlock    (cltr->thread_list_lock);
834}
835
836void unregister( cluster * cltr, thread_desc & thrd ) {
837        lock  (cltr->thread_list_lock __cfaabi_dbg_ctx2);
838        remove(cltr->threads, thrd );
839        unlock(cltr->thread_list_lock);
840}
841
842void doregister( cluster * cltr, processor * proc ) {
843        lock      (cltr->proc_list_lock __cfaabi_dbg_ctx2);
844        push_front(cltr->procs, *proc);
845        unlock    (cltr->proc_list_lock);
846}
847
848void unregister( cluster * cltr, processor * proc ) {
849        lock  (cltr->proc_list_lock __cfaabi_dbg_ctx2);
850        remove(cltr->procs, *proc );
851        unlock(cltr->proc_list_lock);
852}
853
854//-----------------------------------------------------------------------------
855// Debug
856__cfaabi_dbg_debug_do(
857        extern "C" {
858                void __cfaabi_dbg_record(__spinlock_t & this, const char * prev_name) {
859                        this.prev_name = prev_name;
860                        this.prev_thrd = kernelTLS.this_thread;
861                }
862        }
863)
864// Local Variables: //
865// mode: c //
866// tab-width: 4 //
867// End: //
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