source: libcfa/src/concurrency/kernel.cfa @ 1805b1b

arm-ehjacob/cs343-translationjenkins-sandboxnew-astnew-ast-unique-expr
Last change on this file since 1805b1b was 1805b1b, checked in by Peter A. Buhr <pabuhr@…>, 2 years ago

refactor pthread_create into create_pthread, change NULL to 0p

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File size: 27.7 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 : Sun Dec  1 17:52:57 2019
13// Update Count     : 45
14//
15
16#define __cforall_thread__
17
18//C Includes
19#include <stddef.h>
20#include <errno.h>
21#include <string.h>
22extern "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}
30
31//CFA Includes
32#include "time.hfa"
33#include "kernel_private.hfa"
34#include "preemption.hfa"
35#include "startup.hfa"
36
37//Private includes
38#define __CFA_INVOKE_PRIVATE__
39#include "invoke.h"
40
41//-----------------------------------------------------------------------------
42// Some assembly required
43#if defined( __i386 )
44        #define CtxGet( ctx )        \
45                __asm__ volatile (     \
46                        "movl %%esp,%0\n"\
47                        "movl %%ebp,%1\n"\
48                        : "=rm" (ctx.SP),\
49                                "=rm" (ctx.FP) \
50                )
51
52        // mxcr : SSE Status and Control bits (control bits are preserved across function calls)
53        // fcw  : X87 FPU control word (preserved across function calls)
54        #define __x87_store         \
55                uint32_t __mxcr;      \
56                uint16_t __fcw;       \
57                __asm__ volatile (    \
58                        "stmxcsr %0\n"  \
59                        "fnstcw  %1\n"  \
60                        : "=m" (__mxcr),\
61                                "=m" (__fcw)  \
62                )
63
64        #define __x87_load         \
65                __asm__ volatile (   \
66                        "fldcw  %1\n"  \
67                        "ldmxcsr %0\n" \
68                        ::"m" (__mxcr),\
69                                "m" (__fcw)  \
70                )
71
72#elif defined( __x86_64 )
73        #define CtxGet( ctx )        \
74                __asm__ volatile (     \
75                        "movq %%rsp,%0\n"\
76                        "movq %%rbp,%1\n"\
77                        : "=rm" (ctx.SP),\
78                                "=rm" (ctx.FP) \
79                )
80
81        #define __x87_store         \
82                uint32_t __mxcr;      \
83                uint16_t __fcw;       \
84                __asm__ volatile (    \
85                        "stmxcsr %0\n"  \
86                        "fnstcw  %1\n"  \
87                        : "=m" (__mxcr),\
88                                "=m" (__fcw)  \
89                )
90
91        #define __x87_load          \
92                __asm__ volatile (    \
93                        "fldcw  %1\n"   \
94                        "ldmxcsr %0\n"  \
95                        :: "m" (__mxcr),\
96                                "m" (__fcw)  \
97                )
98
99
100#elif defined( __ARM_ARCH )
101#define CtxGet( ctx ) __asm__ ( \
102                "mov %0,%%sp\n"   \
103                "mov %1,%%r11\n"   \
104        : "=rm" (ctx.SP), "=rm" (ctx.FP) )
105#else
106        #error unknown hardware architecture
107#endif
108
109//-----------------------------------------------------------------------------
110//Start and stop routine for the kernel, declared first to make sure they run first
111static void kernel_startup(void)  __attribute__(( constructor( STARTUP_PRIORITY_KERNEL ) ));
112static void kernel_shutdown(void) __attribute__(( destructor ( STARTUP_PRIORITY_KERNEL ) ));
113
114//-----------------------------------------------------------------------------
115// Kernel storage
116KERNEL_STORAGE(cluster,         mainCluster);
117KERNEL_STORAGE(processor,       mainProcessor);
118KERNEL_STORAGE(thread_desc,     mainThread);
119KERNEL_STORAGE(__stack_t,       mainThreadCtx);
120
121cluster     * mainCluster;
122processor   * mainProcessor;
123thread_desc * mainThread;
124
125extern "C" {
126        struct { __dllist_t(cluster) list; __spinlock_t lock; } __cfa_dbg_global_clusters;
127}
128
129size_t __page_size = 0;
130
131//-----------------------------------------------------------------------------
132// Global state
133thread_local struct KernelThreadData kernelTLS __attribute__ ((tls_model ( "initial-exec" ))) = {
134        NULL,                                                                                           // cannot use 0p
135        NULL,
136        { NULL, 1, false, false },
137        6u //this should be seeded better but due to a bug calling rdtsc doesn't work
138};
139
140//-----------------------------------------------------------------------------
141// Struct to steal stack
142struct current_stack_info_t {
143        __stack_t * storage;                                                            // pointer to stack object
144        void * base;                                                                            // base of stack
145        void * limit;                                                                           // stack grows towards stack limit
146        void * context;                                                                         // address of cfa_context_t
147};
148
149void ?{}( current_stack_info_t & this ) {
150        __stack_context_t ctx;
151        CtxGet( ctx );
152        this.base = ctx.FP;
153
154        rlimit r;
155        getrlimit( RLIMIT_STACK, &r);
156        size_t size = r.rlim_cur;
157
158        this.limit = (void *)(((intptr_t)this.base) - size);
159        this.context = &storage_mainThreadCtx;
160}
161
162//-----------------------------------------------------------------------------
163// Main thread construction
164
165void ?{}( coroutine_desc & this, current_stack_info_t * info) with( this ) {
166        stack.storage = info->storage;
167        with(*stack.storage) {
168                limit     = info->limit;
169                base      = info->base;
170        }
171        __attribute__((may_alias)) intptr_t * istorage = (intptr_t*) &stack.storage;
172        *istorage |= 0x1;
173        name = "Main Thread";
174        state = Start;
175        starter = 0p;
176        last = 0p;
177        cancellation = 0p;
178}
179
180void ?{}( thread_desc & this, current_stack_info_t * info) with( this ) {
181        state = Start;
182        self_cor{ info };
183        curr_cor = &self_cor;
184        curr_cluster = mainCluster;
185        self_mon.owner = &this;
186        self_mon.recursion = 1;
187        self_mon_p = &self_mon;
188        next = 0p;
189
190        node.next = 0p;
191        node.prev = 0p;
192        doregister(curr_cluster, this);
193
194        monitors{ &self_mon_p, 1, (fptr_t)0 };
195}
196
197//-----------------------------------------------------------------------------
198// Processor coroutine
199void ?{}(processorCtx_t & this) {
200
201}
202
203// Construct the processor context of non-main processors
204static void ?{}(processorCtx_t & this, processor * proc, current_stack_info_t * info) {
205        (this.__cor){ info };
206        this.proc = proc;
207}
208
209static void start(processor * this);
210void ?{}(processor & this, const char * name, cluster & cltr) with( this ) {
211        this.name = name;
212        this.cltr = &cltr;
213        terminated{ 0 };
214        do_terminate = false;
215        preemption_alarm = 0p;
216        pending_preemption = false;
217        runner.proc = &this;
218
219        idleLock{};
220
221        start( &this );
222}
223
224void ^?{}(processor & this) with( this ){
225        if( ! __atomic_load_n(&do_terminate, __ATOMIC_ACQUIRE) ) {
226                __cfaabi_dbg_print_safe("Kernel : core %p signaling termination\n", &this);
227
228                __atomic_store_n(&do_terminate, true, __ATOMIC_RELAXED);
229                wake( &this );
230
231                P( terminated );
232                verify( kernelTLS.this_processor != &this);
233        }
234
235        pthread_join( kernel_thread, 0p );
236        free( this.stack );
237}
238
239void ?{}(cluster & this, const char * name, Duration preemption_rate) with( this ) {
240        this.name = name;
241        this.preemption_rate = preemption_rate;
242        ready_queue{};
243        ready_queue_lock{};
244
245        procs{ __get };
246        idles{ __get };
247        threads{ __get };
248
249        doregister(this);
250}
251
252void ^?{}(cluster & this) {
253        unregister(this);
254}
255
256//=============================================================================================
257// Kernel Scheduling logic
258//=============================================================================================
259static void runThread(processor * this, thread_desc * dst);
260static void finishRunning(processor * this);
261static void halt(processor * this);
262
263//Main of the processor contexts
264void main(processorCtx_t & runner) {
265        // Because of a bug, we couldn't initialized the seed on construction
266        // Do it here
267        kernelTLS.rand_seed ^= rdtscl();
268
269        processor * this = runner.proc;
270        verify(this);
271
272        __cfaabi_dbg_print_safe("Kernel : core %p starting\n", this);
273
274        doregister(this->cltr, this);
275
276        {
277                // Setup preemption data
278                preemption_scope scope = { this };
279
280                __cfaabi_dbg_print_safe("Kernel : core %p started\n", this);
281
282                thread_desc * readyThread = 0p;
283                for( unsigned int spin_count = 0; ! __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST); spin_count++ )
284                {
285                        readyThread = nextThread( this->cltr );
286
287                        if(readyThread)
288                        {
289                                verify( ! kernelTLS.preemption_state.enabled );
290
291                                runThread(this, readyThread);
292
293                                verify( ! kernelTLS.preemption_state.enabled );
294
295                                //Some actions need to be taken from the kernel
296                                finishRunning(this);
297
298                                spin_count = 0;
299                        }
300                        else
301                        {
302                                // spin(this, &spin_count);
303                                halt(this);
304                        }
305                }
306
307                __cfaabi_dbg_print_safe("Kernel : core %p stopping\n", this);
308        }
309
310        unregister(this->cltr, this);
311
312        V( this->terminated );
313
314        __cfaabi_dbg_print_safe("Kernel : core %p terminated\n", this);
315}
316
317static int * __volatile_errno() __attribute__((noinline));
318static int * __volatile_errno() { asm(""); return &errno; }
319
320// KERNEL ONLY
321// runThread runs a thread by context switching
322// from the processor coroutine to the target thread
323static void runThread(processor * this, thread_desc * thrd_dst) {
324        coroutine_desc * proc_cor = get_coroutine(this->runner);
325
326        // Reset the terminating actions here
327        this->finish.action_code = No_Action;
328
329        // Update global state
330        kernelTLS.this_thread = thrd_dst;
331
332        // set state of processor coroutine to inactive and the thread to active
333        proc_cor->state = proc_cor->state == Halted ? Halted : Inactive;
334        thrd_dst->state = Active;
335
336        // set context switch to the thread that the processor is executing
337        verify( thrd_dst->context.SP );
338        CtxSwitch( &proc_cor->context, &thrd_dst->context );
339        // when CtxSwitch returns we are back in the processor coroutine
340
341        // set state of processor coroutine to active and the thread to inactive
342        thrd_dst->state = thrd_dst->state == Halted ? Halted : Inactive;
343        proc_cor->state = Active;
344}
345
346// KERNEL_ONLY
347static void returnToKernel() {
348        coroutine_desc * proc_cor = get_coroutine(kernelTLS.this_processor->runner);
349        thread_desc * thrd_src = kernelTLS.this_thread;
350
351        // set state of current coroutine to inactive
352        thrd_src->state = thrd_src->state == Halted ? Halted : Inactive;
353        proc_cor->state = Active;
354        int local_errno = *__volatile_errno();
355        #if defined( __i386 ) || defined( __x86_64 )
356                __x87_store;
357        #endif
358
359        // set new coroutine that the processor is executing
360        // and context switch to it
361        verify( proc_cor->context.SP );
362        CtxSwitch( &thrd_src->context, &proc_cor->context );
363
364        // set state of new coroutine to active
365        proc_cor->state = proc_cor->state == Halted ? Halted : Inactive;
366        thrd_src->state = Active;
367
368        #if defined( __i386 ) || defined( __x86_64 )
369                __x87_load;
370        #endif
371        *__volatile_errno() = local_errno;
372}
373
374// KERNEL_ONLY
375// Once a thread has finished running, some of
376// its final actions must be executed from the kernel
377static void finishRunning(processor * this) with( this->finish ) {
378        verify( ! kernelTLS.preemption_state.enabled );
379        choose( action_code ) {
380        case No_Action:
381                break;
382        case Release:
383                unlock( *lock );
384        case Schedule:
385                ScheduleThread( thrd );
386        case Release_Schedule:
387                unlock( *lock );
388                ScheduleThread( thrd );
389        case Release_Multi:
390                for(int i = 0; i < lock_count; i++) {
391                        unlock( *locks[i] );
392                }
393        case Release_Multi_Schedule:
394                for(int i = 0; i < lock_count; i++) {
395                        unlock( *locks[i] );
396                }
397                for(int i = 0; i < thrd_count; i++) {
398                        ScheduleThread( thrds[i] );
399                }
400        case Callback:
401                callback();
402        default:
403                abort("KERNEL ERROR: Unexpected action to run after thread");
404        }
405}
406
407// KERNEL_ONLY
408// Context invoker for processors
409// This is the entry point for processors (kernel threads)
410// It effectively constructs a coroutine by stealing the pthread stack
411static void * CtxInvokeProcessor(void * arg) {
412        processor * proc = (processor *) arg;
413        kernelTLS.this_processor = proc;
414        kernelTLS.this_thread    = 0p;
415        kernelTLS.preemption_state.[enabled, disable_count] = [false, 1];
416        // SKULLDUGGERY: We want to create a context for the processor coroutine
417        // which is needed for the 2-step context switch. However, there is no reason
418        // to waste the perfectly valid stack create by pthread.
419        current_stack_info_t info;
420        __stack_t ctx;
421        info.storage = &ctx;
422        (proc->runner){ proc, &info };
423
424        __cfaabi_dbg_print_safe("Coroutine : created stack %p\n", get_coroutine(proc->runner)->stack.storage);
425
426        //Set global state
427        kernelTLS.this_thread = 0p;
428
429        //We now have a proper context from which to schedule threads
430        __cfaabi_dbg_print_safe("Kernel : core %p created (%p, %p)\n", proc, &proc->runner, &ctx);
431
432        // SKULLDUGGERY: Since the coroutine doesn't have its own stack, we can't
433        // resume it to start it like it normally would, it will just context switch
434        // back to here. Instead directly call the main since we already are on the
435        // appropriate stack.
436        get_coroutine(proc->runner)->state = Active;
437        main( proc->runner );
438        get_coroutine(proc->runner)->state = Halted;
439
440        // Main routine of the core returned, the core is now fully terminated
441        __cfaabi_dbg_print_safe("Kernel : core %p main ended (%p)\n", proc, &proc->runner);
442
443        return 0p;
444}
445
446static void Abort( int ret, const char * func ) {
447        if ( ret ) {
448                abort( "%s : internal error, error(%d) %s.", func, ret, strerror( ret ) );
449        } // if
450} // Abort
451
452void * create_pthread( pthread_t * pthread, void * (*start)(void *), void * arg ) {
453        pthread_attr_t attr;
454
455        Abort( pthread_attr_init( &attr ), "pthread_attr_init" ); // initialize attribute
456
457#ifdef __CFA_DEBUG__
458        size_t guardsize;
459        Abort( pthread_attr_getguardsize( &attr, &guardsize ), "pthread_attr_getguardsize" );
460        Abort( pthread_attr_setguardsize( &attr, guardsize ), "pthread_attr_setguardsize" );
461#endif
462
463        size_t stacksize;
464        Abort( pthread_attr_getstacksize( &attr, &stacksize ), "pthread_attr_getstacksize" ); // default stack size, normally defined by shell limit
465        assert( stacksize >= PTHREAD_STACK_MIN );
466        void * stack = malloc( stacksize );
467        Abort( pthread_attr_setstack( &attr, stack, stacksize ), "pthread_attr_setstack" );
468
469        Abort( pthread_create( pthread, &attr, start, arg ), "pthread_create" );
470        return stack;
471}
472
473static void start(processor * this) {
474        __cfaabi_dbg_print_safe("Kernel : Starting core %p\n", this);
475
476        this->stack = create_pthread( &this->kernel_thread, CtxInvokeProcessor, (void *)this );
477
478        __cfaabi_dbg_print_safe("Kernel : core %p started\n", this);
479}
480
481// KERNEL_ONLY
482void kernel_first_resume( processor * this ) {
483        thread_desc * src = mainThread;
484        coroutine_desc * dst = get_coroutine(this->runner);
485
486        verify( ! kernelTLS.preemption_state.enabled );
487
488        __stack_prepare( &dst->stack, 65000 );
489        CtxStart(&this->runner, CtxInvokeCoroutine);
490
491        verify( ! kernelTLS.preemption_state.enabled );
492
493        dst->last = &src->self_cor;
494        dst->starter = dst->starter ? dst->starter : &src->self_cor;
495
496        // set state of current coroutine to inactive
497        src->state = src->state == Halted ? Halted : Inactive;
498
499        // context switch to specified coroutine
500        verify( dst->context.SP );
501        CtxSwitch( &src->context, &dst->context );
502        // when CtxSwitch returns we are back in the src coroutine
503
504        // set state of new coroutine to active
505        src->state = Active;
506
507        verify( ! kernelTLS.preemption_state.enabled );
508}
509
510// KERNEL_ONLY
511void kernel_last_resume( processor * this ) {
512        coroutine_desc * src = &mainThread->self_cor;
513        coroutine_desc * dst = get_coroutine(this->runner);
514
515        verify( ! kernelTLS.preemption_state.enabled );
516        verify( dst->starter == src );
517        verify( dst->context.SP );
518
519        // context switch to the processor
520        CtxSwitch( &src->context, &dst->context );
521}
522
523//-----------------------------------------------------------------------------
524// Scheduler routines
525
526// KERNEL ONLY
527void ScheduleThread( thread_desc * thrd ) {
528        verify( thrd );
529        verify( thrd->state != Halted );
530
531        verify( ! kernelTLS.preemption_state.enabled );
532
533        verifyf( thrd->next == 0p, "Expected null got %p", thrd->next );
534
535        with( *thrd->curr_cluster ) {
536                lock  ( ready_queue_lock __cfaabi_dbg_ctx2 );
537                bool was_empty = !(ready_queue != 0);
538                append( ready_queue, thrd );
539                unlock( ready_queue_lock );
540
541                if(was_empty) {
542                        lock      (proc_list_lock __cfaabi_dbg_ctx2);
543                        if(idles) {
544                                wake_fast(idles.head);
545                        }
546                        unlock    (proc_list_lock);
547                }
548                else if( struct processor * idle = idles.head ) {
549                        wake_fast(idle);
550                }
551
552        }
553
554        verify( ! kernelTLS.preemption_state.enabled );
555}
556
557// KERNEL ONLY
558thread_desc * nextThread(cluster * this) with( *this ) {
559        verify( ! kernelTLS.preemption_state.enabled );
560        lock( ready_queue_lock __cfaabi_dbg_ctx2 );
561        thread_desc * head = pop_head( ready_queue );
562        unlock( ready_queue_lock );
563        verify( ! kernelTLS.preemption_state.enabled );
564        return head;
565}
566
567void BlockInternal() {
568        disable_interrupts();
569        verify( ! kernelTLS.preemption_state.enabled );
570        returnToKernel();
571        verify( ! kernelTLS.preemption_state.enabled );
572        enable_interrupts( __cfaabi_dbg_ctx );
573}
574
575void BlockInternal( __spinlock_t * lock ) {
576        disable_interrupts();
577        with( *kernelTLS.this_processor ) {
578                finish.action_code = Release;
579                finish.lock        = lock;
580        }
581
582        verify( ! kernelTLS.preemption_state.enabled );
583        returnToKernel();
584        verify( ! kernelTLS.preemption_state.enabled );
585
586        enable_interrupts( __cfaabi_dbg_ctx );
587}
588
589void BlockInternal( thread_desc * thrd ) {
590        disable_interrupts();
591        with( * kernelTLS.this_processor ) {
592                finish.action_code = Schedule;
593                finish.thrd        = thrd;
594        }
595
596        verify( ! kernelTLS.preemption_state.enabled );
597        returnToKernel();
598        verify( ! kernelTLS.preemption_state.enabled );
599
600        enable_interrupts( __cfaabi_dbg_ctx );
601}
602
603void BlockInternal( __spinlock_t * lock, thread_desc * thrd ) {
604        assert(thrd);
605        disable_interrupts();
606        with( * kernelTLS.this_processor ) {
607                finish.action_code = Release_Schedule;
608                finish.lock        = lock;
609                finish.thrd        = thrd;
610        }
611
612        verify( ! kernelTLS.preemption_state.enabled );
613        returnToKernel();
614        verify( ! kernelTLS.preemption_state.enabled );
615
616        enable_interrupts( __cfaabi_dbg_ctx );
617}
618
619void BlockInternal(__spinlock_t * locks [], unsigned short count) {
620        disable_interrupts();
621        with( * kernelTLS.this_processor ) {
622                finish.action_code = Release_Multi;
623                finish.locks       = locks;
624                finish.lock_count  = count;
625        }
626
627        verify( ! kernelTLS.preemption_state.enabled );
628        returnToKernel();
629        verify( ! kernelTLS.preemption_state.enabled );
630
631        enable_interrupts( __cfaabi_dbg_ctx );
632}
633
634void BlockInternal(__spinlock_t * locks [], unsigned short lock_count, thread_desc * thrds [], unsigned short thrd_count) {
635        disable_interrupts();
636        with( *kernelTLS.this_processor ) {
637                finish.action_code = Release_Multi_Schedule;
638                finish.locks       = locks;
639                finish.lock_count  = lock_count;
640                finish.thrds       = thrds;
641                finish.thrd_count  = thrd_count;
642        }
643
644        verify( ! kernelTLS.preemption_state.enabled );
645        returnToKernel();
646        verify( ! kernelTLS.preemption_state.enabled );
647
648        enable_interrupts( __cfaabi_dbg_ctx );
649}
650
651void BlockInternal(__finish_callback_fptr_t callback) {
652        disable_interrupts();
653        with( *kernelTLS.this_processor ) {
654                finish.action_code = Callback;
655                finish.callback    = callback;
656        }
657
658        verify( ! kernelTLS.preemption_state.enabled );
659        returnToKernel();
660        verify( ! kernelTLS.preemption_state.enabled );
661
662        enable_interrupts( __cfaabi_dbg_ctx );
663}
664
665// KERNEL ONLY
666void LeaveThread(__spinlock_t * lock, thread_desc * thrd) {
667        verify( ! kernelTLS.preemption_state.enabled );
668        with( * kernelTLS.this_processor ) {
669                finish.action_code = thrd ? Release_Schedule : Release;
670                finish.lock        = lock;
671                finish.thrd        = thrd;
672        }
673
674        returnToKernel();
675}
676
677//=============================================================================================
678// Kernel Setup logic
679//=============================================================================================
680//-----------------------------------------------------------------------------
681// Kernel boot procedures
682static void kernel_startup(void) {
683        verify( ! kernelTLS.preemption_state.enabled );
684        __cfaabi_dbg_print_safe("Kernel : Starting\n");
685
686        __page_size = sysconf( _SC_PAGESIZE );
687
688        __cfa_dbg_global_clusters.list{ __get };
689        __cfa_dbg_global_clusters.lock{};
690
691        // Initialize the main cluster
692        mainCluster = (cluster *)&storage_mainCluster;
693        (*mainCluster){"Main Cluster"};
694
695        __cfaabi_dbg_print_safe("Kernel : Main cluster ready\n");
696
697        // Start by initializing the main thread
698        // SKULLDUGGERY: the mainThread steals the process main thread
699        // which will then be scheduled by the mainProcessor normally
700        mainThread = (thread_desc *)&storage_mainThread;
701        current_stack_info_t info;
702        info.storage = (__stack_t*)&storage_mainThreadCtx;
703        (*mainThread){ &info };
704
705        __cfaabi_dbg_print_safe("Kernel : Main thread ready\n");
706
707
708
709        // Construct the processor context of the main processor
710        void ?{}(processorCtx_t & this, processor * proc) {
711                (this.__cor){ "Processor" };
712                this.__cor.starter = 0p;
713                this.proc = proc;
714        }
715
716        void ?{}(processor & this) with( this ) {
717                name = "Main Processor";
718                cltr = mainCluster;
719                terminated{ 0 };
720                do_terminate = false;
721                preemption_alarm = 0p;
722                pending_preemption = false;
723                kernel_thread = pthread_self();
724
725                runner{ &this };
726                __cfaabi_dbg_print_safe("Kernel : constructed main processor context %p\n", &runner);
727        }
728
729        // Initialize the main processor and the main processor ctx
730        // (the coroutine that contains the processing control flow)
731        mainProcessor = (processor *)&storage_mainProcessor;
732        (*mainProcessor){};
733
734        //initialize the global state variables
735        kernelTLS.this_processor = mainProcessor;
736        kernelTLS.this_thread    = mainThread;
737
738        // Enable preemption
739        kernel_start_preemption();
740
741        // Add the main thread to the ready queue
742        // once resume is called on mainProcessor->runner the mainThread needs to be scheduled like any normal thread
743        ScheduleThread(mainThread);
744
745        // SKULLDUGGERY: Force a context switch to the main processor to set the main thread's context to the current UNIX
746        // context. Hence, the main thread does not begin through CtxInvokeThread, like all other threads. The trick here is that
747        // mainThread is on the ready queue when this call is made.
748        kernel_first_resume( kernelTLS.this_processor );
749
750
751
752        // THE SYSTEM IS NOW COMPLETELY RUNNING
753        __cfaabi_dbg_print_safe("Kernel : Started\n--------------------------------------------------\n\n");
754
755        verify( ! kernelTLS.preemption_state.enabled );
756        enable_interrupts( __cfaabi_dbg_ctx );
757        verify( TL_GET( preemption_state.enabled ) );
758}
759
760static void kernel_shutdown(void) {
761        __cfaabi_dbg_print_safe("\n--------------------------------------------------\nKernel : Shutting down\n");
762
763        verify( TL_GET( preemption_state.enabled ) );
764        disable_interrupts();
765        verify( ! kernelTLS.preemption_state.enabled );
766
767        // SKULLDUGGERY: Notify the mainProcessor it needs to terminates.
768        // When its coroutine terminates, it return control to the mainThread
769        // which is currently here
770        __atomic_store_n(&mainProcessor->do_terminate, true, __ATOMIC_RELEASE);
771        kernel_last_resume( kernelTLS.this_processor );
772        mainThread->self_cor.state = Halted;
773
774        // THE SYSTEM IS NOW COMPLETELY STOPPED
775
776        // Disable preemption
777        kernel_stop_preemption();
778
779        // Destroy the main processor and its context in reverse order of construction
780        // These were manually constructed so we need manually destroy them
781        ^(mainProcessor->runner){};
782        ^(mainProcessor){};
783
784        // Final step, destroy the main thread since it is no longer needed
785        // Since we provided a stack to this taxk it will not destroy anything
786        ^(mainThread){};
787
788        ^(__cfa_dbg_global_clusters.list){};
789        ^(__cfa_dbg_global_clusters.lock){};
790
791        __cfaabi_dbg_print_safe("Kernel : Shutdown complete\n");
792}
793
794//=============================================================================================
795// Kernel Quiescing
796//=============================================================================================
797static void halt(processor * this) with( *this ) {
798        // verify( ! __atomic_load_n(&do_terminate, __ATOMIC_SEQ_CST) );
799
800        with( *cltr ) {
801                lock      (proc_list_lock __cfaabi_dbg_ctx2);
802                remove    (procs, *this);
803                push_front(idles, *this);
804                unlock    (proc_list_lock);
805        }
806
807        __cfaabi_dbg_print_safe("Kernel : Processor %p ready to sleep\n", this);
808
809        wait( idleLock );
810
811        __cfaabi_dbg_print_safe("Kernel : Processor %p woke up and ready to run\n", this);
812
813        with( *cltr ) {
814                lock      (proc_list_lock __cfaabi_dbg_ctx2);
815                remove    (idles, *this);
816                push_front(procs, *this);
817                unlock    (proc_list_lock);
818        }
819}
820
821//=============================================================================================
822// Unexpected Terminating logic
823//=============================================================================================
824static __spinlock_t kernel_abort_lock;
825static bool kernel_abort_called = false;
826
827void * kernel_abort(void) __attribute__ ((__nothrow__)) {
828        // abort cannot be recursively entered by the same or different processors because all signal handlers return when
829        // the globalAbort flag is true.
830        lock( kernel_abort_lock __cfaabi_dbg_ctx2 );
831
832        // first task to abort ?
833        if ( kernel_abort_called ) {                    // not first task to abort ?
834                unlock( kernel_abort_lock );
835
836                sigset_t mask;
837                sigemptyset( &mask );
838                sigaddset( &mask, SIGALRM );            // block SIGALRM signals
839                sigsuspend( &mask );                    // block the processor to prevent further damage during abort
840                _exit( EXIT_FAILURE );                  // if processor unblocks before it is killed, terminate it
841        }
842        else {
843                kernel_abort_called = true;
844                unlock( kernel_abort_lock );
845        }
846
847        return kernelTLS.this_thread;
848}
849
850void kernel_abort_msg( void * kernel_data, char * abort_text, int abort_text_size ) {
851        thread_desc * thrd = kernel_data;
852
853        if(thrd) {
854                int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
855                __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
856
857                if ( &thrd->self_cor != thrd->curr_cor ) {
858                        len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
859                        __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
860                }
861                else {
862                        __cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
863                }
864        }
865        else {
866                int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
867                __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
868        }
869}
870
871int kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
872        return get_coroutine(kernelTLS.this_thread) == get_coroutine(mainThread) ? 4 : 2;
873}
874
875static __spinlock_t kernel_debug_lock;
876
877extern "C" {
878        void __cfaabi_bits_acquire() {
879                lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
880        }
881
882        void __cfaabi_bits_release() {
883                unlock( kernel_debug_lock );
884        }
885}
886
887//=============================================================================================
888// Kernel Utilities
889//=============================================================================================
890//-----------------------------------------------------------------------------
891// Locks
892void  ?{}( semaphore & this, int count = 1 ) {
893        (this.lock){};
894        this.count = count;
895        (this.waiting){};
896}
897void ^?{}(semaphore & this) {}
898
899void P(semaphore & this) with( this ){
900        lock( lock __cfaabi_dbg_ctx2 );
901        count -= 1;
902        if ( count < 0 ) {
903                // queue current task
904                append( waiting, kernelTLS.this_thread );
905
906                // atomically release spin lock and block
907                BlockInternal( &lock );
908        }
909        else {
910            unlock( lock );
911        }
912}
913
914void V(semaphore & this) with( this ) {
915        thread_desc * thrd = 0p;
916        lock( lock __cfaabi_dbg_ctx2 );
917        count += 1;
918        if ( count <= 0 ) {
919                // remove task at head of waiting list
920                thrd = pop_head( waiting );
921        }
922
923        unlock( lock );
924
925        // make new owner
926        WakeThread( thrd );
927}
928
929//-----------------------------------------------------------------------------
930// Global Queues
931void doregister( cluster     & cltr ) {
932        lock      ( __cfa_dbg_global_clusters.lock __cfaabi_dbg_ctx2);
933        push_front( __cfa_dbg_global_clusters.list, cltr );
934        unlock    ( __cfa_dbg_global_clusters.lock );
935}
936
937void unregister( cluster     & cltr ) {
938        lock  ( __cfa_dbg_global_clusters.lock __cfaabi_dbg_ctx2);
939        remove( __cfa_dbg_global_clusters.list, cltr );
940        unlock( __cfa_dbg_global_clusters.lock );
941}
942
943void doregister( cluster * cltr, thread_desc & thrd ) {
944        lock      (cltr->thread_list_lock __cfaabi_dbg_ctx2);
945        cltr->nthreads += 1;
946        push_front(cltr->threads, thrd);
947        unlock    (cltr->thread_list_lock);
948}
949
950void unregister( cluster * cltr, thread_desc & thrd ) {
951        lock  (cltr->thread_list_lock __cfaabi_dbg_ctx2);
952        remove(cltr->threads, thrd );
953        cltr->nthreads -= 1;
954        unlock(cltr->thread_list_lock);
955}
956
957void doregister( cluster * cltr, processor * proc ) {
958        lock      (cltr->proc_list_lock __cfaabi_dbg_ctx2);
959        cltr->nprocessors += 1;
960        push_front(cltr->procs, *proc);
961        unlock    (cltr->proc_list_lock);
962}
963
964void unregister( cluster * cltr, processor * proc ) {
965        lock  (cltr->proc_list_lock __cfaabi_dbg_ctx2);
966        remove(cltr->procs, *proc );
967        cltr->nprocessors -= 1;
968        unlock(cltr->proc_list_lock);
969}
970
971//-----------------------------------------------------------------------------
972// Debug
973__cfaabi_dbg_debug_do(
974        extern "C" {
975                void __cfaabi_dbg_record(__spinlock_t & this, const char * prev_name) {
976                        this.prev_name = prev_name;
977                        this.prev_thrd = kernelTLS.this_thread;
978                }
979        }
980)
981
982//-----------------------------------------------------------------------------
983// Debug
984bool threading_enabled(void) {
985        return true;
986}
987// Local Variables: //
988// mode: c //
989// tab-width: 4 //
990// End: //
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