source: libcfa/src/concurrency/kernel.cfa @ 52142c2

arm-ehjacob/cs343-translationjenkins-sandboxnew-astnew-ast-unique-expr
Last change on this file since 52142c2 was 52142c2, checked in by Peter A. Buhr <pabuhr@…>, 21 months ago

Merge branch 'master' of plg.uwaterloo.ca:software/cfa/cfa-cc

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1//
2// Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo
3//
4// The contents of this file are covered under the licence agreement in the
5// file "LICENCE" distributed with Cforall.
6//
7// kernel.c --
8//
9// Author           : Thierry Delisle
10// Created On       : Tue Jan 17 12:27:26 2017
11// Last Modified By : Peter A. Buhr
12// Last Modified On : Tue 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>
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#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
112static void kernel_startup(void)  __attribute__(( constructor( STARTUP_PRIORITY_KERNEL ) ));
113static void kernel_shutdown(void) __attribute__(( destructor ( STARTUP_PRIORITY_KERNEL ) ));
114
115//-----------------------------------------------------------------------------
116// Kernel storage
117KERNEL_STORAGE(cluster,         mainCluster);
118KERNEL_STORAGE(processor,       mainProcessor);
119KERNEL_STORAGE(thread_desc,     mainThread);
120KERNEL_STORAGE(__stack_t,       mainThreadCtx);
121
122cluster     * mainCluster;
123processor   * mainProcessor;
124thread_desc * mainThread;
125
126extern "C" {
127        struct { __dllist_t(cluster) list; __spinlock_t lock; } __cfa_dbg_global_clusters;
128}
129
130size_t __page_size = 0;
131
132//-----------------------------------------------------------------------------
133// Global state
134thread_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
143struct 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
150void ?{}( 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
166void ?{}( coroutine_desc & 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
181void ?{}( thread_desc & 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
200void ?{}(processorCtx_t & this) {
201
202}
203
204// Construct the processor context of non-main processors
205static void ?{}(processorCtx_t & this, processor * proc, current_stack_info_t * info) {
206        (this.__cor){ info };
207        this.proc = proc;
208}
209
210static void start(processor * this);
211void ?{}(processor & this, const char name[], cluster & cltr) with( this ) {
212        this.name = name;
213        this.cltr = &cltr;
214        terminated{ 0 };
215        do_terminate = false;
216        preemption_alarm = 0p;
217        pending_preemption = false;
218        runner.proc = &this;
219
220        idleLock{};
221
222        start( &this );
223}
224
225void ^?{}(processor & this) with( this ){
226        if( ! __atomic_load_n(&do_terminate, __ATOMIC_ACQUIRE) ) {
227                __cfaabi_dbg_print_safe("Kernel : core %p signaling termination\n", &this);
228
229                __atomic_store_n(&do_terminate, true, __ATOMIC_RELAXED);
230                wake( &this );
231
232                P( terminated );
233                verify( kernelTLS.this_processor != &this);
234        }
235
236        pthread_join( kernel_thread, 0p );
237        free( this.stack );
238}
239
240void ?{}(cluster & this, const char name[], Duration preemption_rate) with( this ) {
241        this.name = name;
242        this.preemption_rate = preemption_rate;
243        ready_queue{};
244        ready_queue_lock{};
245
246        procs{ __get };
247        idles{ __get };
248        threads{ __get };
249
250        doregister(this);
251}
252
253void ^?{}(cluster & this) {
254        unregister(this);
255}
256
257//=============================================================================================
258// Kernel Scheduling logic
259//=============================================================================================
260static void runThread(processor * this, thread_desc * dst);
261static void finishRunning(processor * this);
262static void halt(processor * this);
263
264//Main of the processor contexts
265void main(processorCtx_t & runner) {
266        // Because of a bug, we couldn't initialized the seed on construction
267        // Do it here
268        kernelTLS.rand_seed ^= rdtscl();
269
270        processor * this = runner.proc;
271        verify(this);
272
273        __cfaabi_dbg_print_safe("Kernel : core %p starting\n", this);
274
275        doregister(this->cltr, this);
276
277        {
278                // Setup preemption data
279                preemption_scope scope = { this };
280
281                __cfaabi_dbg_print_safe("Kernel : core %p started\n", this);
282
283                thread_desc * readyThread = 0p;
284                for( unsigned int spin_count = 0; ! __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST); spin_count++ ) {
285                        readyThread = nextThread( this->cltr );
286
287                        if(readyThread) {
288                                verify( ! kernelTLS.preemption_state.enabled );
289
290                                runThread(this, readyThread);
291
292                                verify( ! kernelTLS.preemption_state.enabled );
293
294                                //Some actions need to be taken from the kernel
295                                finishRunning(this);
296
297                                spin_count = 0;
298                        } else {
299                                // spin(this, &spin_count);
300                                halt(this);
301                        }
302                }
303
304                __cfaabi_dbg_print_safe("Kernel : core %p stopping\n", this);
305        }
306
307        unregister(this->cltr, this);
308
309        V( this->terminated );
310
311        __cfaabi_dbg_print_safe("Kernel : core %p terminated\n", this);
312}
313
314static int * __volatile_errno() __attribute__((noinline));
315static int * __volatile_errno() { asm(""); return &errno; }
316
317// KERNEL ONLY
318// runThread runs a thread by context switching
319// from the processor coroutine to the target thread
320static void runThread(processor * this, thread_desc * thrd_dst) {
321        coroutine_desc * proc_cor = get_coroutine(this->runner);
322
323        // Reset the terminating actions here
324        this->finish.action_code = No_Action;
325
326        // Update global state
327        kernelTLS.this_thread = thrd_dst;
328
329        // set state of processor coroutine to inactive and the thread to active
330        proc_cor->state = proc_cor->state == Halted ? Halted : Inactive;
331        thrd_dst->state = Active;
332
333        // set context switch to the thread that the processor is executing
334        verify( thrd_dst->context.SP );
335        CtxSwitch( &proc_cor->context, &thrd_dst->context );
336        // when CtxSwitch returns we are back in the processor coroutine
337
338        // set state of processor coroutine to active and the thread to inactive
339        thrd_dst->state = thrd_dst->state == Halted ? Halted : Inactive;
340        proc_cor->state = Active;
341}
342
343// KERNEL_ONLY
344static void returnToKernel() {
345        coroutine_desc * proc_cor = get_coroutine(kernelTLS.this_processor->runner);
346        thread_desc * thrd_src = kernelTLS.this_thread;
347
348        // set state of current coroutine to inactive
349        thrd_src->state = thrd_src->state == Halted ? Halted : Inactive;
350        proc_cor->state = Active;
351        int local_errno = *__volatile_errno();
352        #if defined( __i386 ) || defined( __x86_64 )
353                __x87_store;
354        #endif
355
356        // set new coroutine that the processor is executing
357        // and context switch to it
358        verify( proc_cor->context.SP );
359        CtxSwitch( &thrd_src->context, &proc_cor->context );
360
361        // set state of new coroutine to active
362        proc_cor->state = proc_cor->state == Halted ? Halted : Inactive;
363        thrd_src->state = Active;
364
365        #if defined( __i386 ) || defined( __x86_64 )
366                __x87_load;
367        #endif
368        *__volatile_errno() = local_errno;
369}
370
371// KERNEL_ONLY
372// Once a thread has finished running, some of
373// its final actions must be executed from the kernel
374static void finishRunning(processor * this) with( this->finish ) {
375        verify( ! kernelTLS.preemption_state.enabled );
376        choose( action_code ) {
377        case No_Action:
378                break;
379        case Release:
380                unlock( *lock );
381        case Schedule:
382                ScheduleThread( thrd );
383        case Release_Schedule:
384                unlock( *lock );
385                ScheduleThread( thrd );
386        case Release_Multi:
387                for(int i = 0; i < lock_count; i++) {
388                        unlock( *locks[i] );
389                }
390        case Release_Multi_Schedule:
391                for(int i = 0; i < lock_count; i++) {
392                        unlock( *locks[i] );
393                }
394                for(int i = 0; i < thrd_count; i++) {
395                        ScheduleThread( thrds[i] );
396                }
397        case Callback:
398                callback();
399        default:
400                abort("KERNEL ERROR: Unexpected action to run after thread");
401        }
402}
403
404// KERNEL_ONLY
405// Context invoker for processors
406// This is the entry point for processors (kernel threads)
407// It effectively constructs a coroutine by stealing the pthread stack
408static void * CtxInvokeProcessor(void * arg) {
409        processor * proc = (processor *) arg;
410        kernelTLS.this_processor = proc;
411        kernelTLS.this_thread    = 0p;
412        kernelTLS.preemption_state.[enabled, disable_count] = [false, 1];
413        // SKULLDUGGERY: We want to create a context for the processor coroutine
414        // which is needed for the 2-step context switch. However, there is no reason
415        // to waste the perfectly valid stack create by pthread.
416        current_stack_info_t info;
417        __stack_t ctx;
418        info.storage = &ctx;
419        (proc->runner){ proc, &info };
420
421        __cfaabi_dbg_print_safe("Coroutine : created stack %p\n", get_coroutine(proc->runner)->stack.storage);
422
423        //Set global state
424        kernelTLS.this_thread = 0p;
425
426        //We now have a proper context from which to schedule threads
427        __cfaabi_dbg_print_safe("Kernel : core %p created (%p, %p)\n", proc, &proc->runner, &ctx);
428
429        // SKULLDUGGERY: Since the coroutine doesn't have its own stack, we can't
430        // resume it to start it like it normally would, it will just context switch
431        // back to here. Instead directly call the main since we already are on the
432        // appropriate stack.
433        get_coroutine(proc->runner)->state = Active;
434        main( proc->runner );
435        get_coroutine(proc->runner)->state = Halted;
436
437        // Main routine of the core returned, the core is now fully terminated
438        __cfaabi_dbg_print_safe("Kernel : core %p main ended (%p)\n", proc, &proc->runner);
439
440        return 0p;
441}
442
443static void Abort( int ret, const char func[] ) {
444        if ( ret ) {                                                                            // pthread routines return errno values
445                abort( "%s : internal error, error(%d) %s.", func, ret, strerror( ret ) );
446        } // if
447} // Abort
448
449void * create_pthread( pthread_t * pthread, void * (*start)(void *), void * arg ) {
450        pthread_attr_t attr;
451
452        Abort( pthread_attr_init( &attr ), "pthread_attr_init" ); // initialize attribute
453
454        size_t stacksize;
455        // default stack size, normally defined by shell limit
456        Abort( pthread_attr_getstacksize( &attr, &stacksize ), "pthread_attr_getstacksize" );
457        assert( stacksize >= PTHREAD_STACK_MIN );
458
459        void * stack;
460        __cfaabi_dbg_debug_do(
461                stack = memalign( __page_size, stacksize + __page_size );
462                // pthread has no mechanism to create the guard page in user supplied stack.
463                if ( mprotect( stack, __page_size, PROT_NONE ) == -1 ) {
464                        abort( "mprotect : internal error, mprotect failure, error(%d) %s.", errno, strerror( errno ) );
465                } // if
466        );
467        __cfaabi_dbg_no_debug_do(
468                stack = malloc( stacksize );
469        );
470
471        Abort( pthread_attr_setstack( &attr, stack, stacksize ), "pthread_attr_setstack" );
472
473        Abort( pthread_create( pthread, &attr, start, arg ), "pthread_create" );
474        return stack;
475}
476
477static void start(processor * this) {
478        __cfaabi_dbg_print_safe("Kernel : Starting core %p\n", this);
479
480        this->stack = create_pthread( &this->kernel_thread, CtxInvokeProcessor, (void *)this );
481
482        __cfaabi_dbg_print_safe("Kernel : core %p started\n", this);
483}
484
485// KERNEL_ONLY
486void kernel_first_resume( processor * this ) {
487        thread_desc * src = mainThread;
488        coroutine_desc * dst = get_coroutine(this->runner);
489
490        verify( ! kernelTLS.preemption_state.enabled );
491
492        kernelTLS.this_thread->curr_cor = dst;
493        __stack_prepare( &dst->stack, 65000 );
494        CtxStart(main, dst, this->runner, CtxInvokeCoroutine);
495
496        verify( ! kernelTLS.preemption_state.enabled );
497
498        dst->last = &src->self_cor;
499        dst->starter = dst->starter ? dst->starter : &src->self_cor;
500
501        // set state of current coroutine to inactive
502        src->state = src->state == Halted ? Halted : Inactive;
503
504        // context switch to specified coroutine
505        verify( dst->context.SP );
506        CtxSwitch( &src->context, &dst->context );
507        // when CtxSwitch returns we are back in the src coroutine
508
509        mainThread->curr_cor = &mainThread->self_cor;
510
511        // set state of new coroutine to active
512        src->state = Active;
513
514        verify( ! kernelTLS.preemption_state.enabled );
515}
516
517// KERNEL_ONLY
518void kernel_last_resume( processor * this ) {
519        coroutine_desc * src = &mainThread->self_cor;
520        coroutine_desc * dst = get_coroutine(this->runner);
521
522        verify( ! kernelTLS.preemption_state.enabled );
523        verify( dst->starter == src );
524        verify( dst->context.SP );
525
526        // context switch to the processor
527        CtxSwitch( &src->context, &dst->context );
528}
529
530//-----------------------------------------------------------------------------
531// Scheduler routines
532
533// KERNEL ONLY
534void ScheduleThread( thread_desc * thrd ) {
535        verify( thrd );
536        verify( thrd->state != Halted );
537
538        verify( ! kernelTLS.preemption_state.enabled );
539
540        verifyf( thrd->next == 0p, "Expected null got %p", thrd->next );
541
542        with( *thrd->curr_cluster ) {
543                lock  ( ready_queue_lock __cfaabi_dbg_ctx2 );
544                bool was_empty = !(ready_queue != 0);
545                append( ready_queue, thrd );
546                unlock( ready_queue_lock );
547
548                if(was_empty) {
549                        lock      (proc_list_lock __cfaabi_dbg_ctx2);
550                        if(idles) {
551                                wake_fast(idles.head);
552                        }
553                        unlock    (proc_list_lock);
554                }
555                else if( struct processor * idle = idles.head ) {
556                        wake_fast(idle);
557                }
558
559        }
560
561        verify( ! kernelTLS.preemption_state.enabled );
562}
563
564// KERNEL ONLY
565thread_desc * nextThread(cluster * this) with( *this ) {
566        verify( ! kernelTLS.preemption_state.enabled );
567        lock( ready_queue_lock __cfaabi_dbg_ctx2 );
568        thread_desc * head = pop_head( ready_queue );
569        unlock( ready_queue_lock );
570        verify( ! kernelTLS.preemption_state.enabled );
571        return head;
572}
573
574void BlockInternal() {
575        disable_interrupts();
576        verify( ! kernelTLS.preemption_state.enabled );
577        returnToKernel();
578        verify( ! kernelTLS.preemption_state.enabled );
579        enable_interrupts( __cfaabi_dbg_ctx );
580}
581
582void BlockInternal( __spinlock_t * lock ) {
583        disable_interrupts();
584        with( *kernelTLS.this_processor ) {
585                finish.action_code = Release;
586                finish.lock        = lock;
587        }
588
589        verify( ! kernelTLS.preemption_state.enabled );
590        returnToKernel();
591        verify( ! kernelTLS.preemption_state.enabled );
592
593        enable_interrupts( __cfaabi_dbg_ctx );
594}
595
596void BlockInternal( thread_desc * thrd ) {
597        disable_interrupts();
598        with( * kernelTLS.this_processor ) {
599                finish.action_code = Schedule;
600                finish.thrd        = thrd;
601        }
602
603        verify( ! kernelTLS.preemption_state.enabled );
604        returnToKernel();
605        verify( ! kernelTLS.preemption_state.enabled );
606
607        enable_interrupts( __cfaabi_dbg_ctx );
608}
609
610void BlockInternal( __spinlock_t * lock, thread_desc * thrd ) {
611        assert(thrd);
612        disable_interrupts();
613        with( * kernelTLS.this_processor ) {
614                finish.action_code = Release_Schedule;
615                finish.lock        = lock;
616                finish.thrd        = thrd;
617        }
618
619        verify( ! kernelTLS.preemption_state.enabled );
620        returnToKernel();
621        verify( ! kernelTLS.preemption_state.enabled );
622
623        enable_interrupts( __cfaabi_dbg_ctx );
624}
625
626void BlockInternal(__spinlock_t * locks [], unsigned short count) {
627        disable_interrupts();
628        with( * kernelTLS.this_processor ) {
629                finish.action_code = Release_Multi;
630                finish.locks       = locks;
631                finish.lock_count  = count;
632        }
633
634        verify( ! kernelTLS.preemption_state.enabled );
635        returnToKernel();
636        verify( ! kernelTLS.preemption_state.enabled );
637
638        enable_interrupts( __cfaabi_dbg_ctx );
639}
640
641void BlockInternal(__spinlock_t * locks [], unsigned short lock_count, thread_desc * thrds [], unsigned short thrd_count) {
642        disable_interrupts();
643        with( *kernelTLS.this_processor ) {
644                finish.action_code = Release_Multi_Schedule;
645                finish.locks       = locks;
646                finish.lock_count  = lock_count;
647                finish.thrds       = thrds;
648                finish.thrd_count  = thrd_count;
649        }
650
651        verify( ! kernelTLS.preemption_state.enabled );
652        returnToKernel();
653        verify( ! kernelTLS.preemption_state.enabled );
654
655        enable_interrupts( __cfaabi_dbg_ctx );
656}
657
658void BlockInternal(__finish_callback_fptr_t callback) {
659        disable_interrupts();
660        with( *kernelTLS.this_processor ) {
661                finish.action_code = Callback;
662                finish.callback    = callback;
663        }
664
665        verify( ! kernelTLS.preemption_state.enabled );
666        returnToKernel();
667        verify( ! kernelTLS.preemption_state.enabled );
668
669        enable_interrupts( __cfaabi_dbg_ctx );
670}
671
672// KERNEL ONLY
673void LeaveThread(__spinlock_t * lock, thread_desc * thrd) {
674        verify( ! kernelTLS.preemption_state.enabled );
675        with( * kernelTLS.this_processor ) {
676                finish.action_code = thrd ? Release_Schedule : Release;
677                finish.lock        = lock;
678                finish.thrd        = thrd;
679        }
680
681        returnToKernel();
682}
683
684//=============================================================================================
685// Kernel Setup logic
686//=============================================================================================
687//-----------------------------------------------------------------------------
688// Kernel boot procedures
689static void kernel_startup(void) {
690        verify( ! kernelTLS.preemption_state.enabled );
691        __cfaabi_dbg_print_safe("Kernel : Starting\n");
692
693        __page_size = sysconf( _SC_PAGESIZE );
694
695        __cfa_dbg_global_clusters.list{ __get };
696        __cfa_dbg_global_clusters.lock{};
697
698        // Initialize the main cluster
699        mainCluster = (cluster *)&storage_mainCluster;
700        (*mainCluster){"Main Cluster"};
701
702        __cfaabi_dbg_print_safe("Kernel : Main cluster ready\n");
703
704        // Start by initializing the main thread
705        // SKULLDUGGERY: the mainThread steals the process main thread
706        // which will then be scheduled by the mainProcessor normally
707        mainThread = (thread_desc *)&storage_mainThread;
708        current_stack_info_t info;
709        info.storage = (__stack_t*)&storage_mainThreadCtx;
710        (*mainThread){ &info };
711
712        __cfaabi_dbg_print_safe("Kernel : Main thread ready\n");
713
714
715
716        // Construct the processor context of the main processor
717        void ?{}(processorCtx_t & this, processor * proc) {
718                (this.__cor){ "Processor" };
719                this.__cor.starter = 0p;
720                this.proc = proc;
721        }
722
723        void ?{}(processor & this) with( this ) {
724                name = "Main Processor";
725                cltr = mainCluster;
726                terminated{ 0 };
727                do_terminate = false;
728                preemption_alarm = 0p;
729                pending_preemption = false;
730                kernel_thread = pthread_self();
731
732                runner{ &this };
733                __cfaabi_dbg_print_safe("Kernel : constructed main processor context %p\n", &runner);
734        }
735
736        // Initialize the main processor and the main processor ctx
737        // (the coroutine that contains the processing control flow)
738        mainProcessor = (processor *)&storage_mainProcessor;
739        (*mainProcessor){};
740
741        //initialize the global state variables
742        kernelTLS.this_processor = mainProcessor;
743        kernelTLS.this_thread    = mainThread;
744
745        // Enable preemption
746        kernel_start_preemption();
747
748        // Add the main thread to the ready queue
749        // once resume is called on mainProcessor->runner the mainThread needs to be scheduled like any normal thread
750        ScheduleThread(mainThread);
751
752        // SKULLDUGGERY: Force a context switch to the main processor to set the main thread's context to the current UNIX
753        // context. Hence, the main thread does not begin through CtxInvokeThread, like all other threads. The trick here is that
754        // mainThread is on the ready queue when this call is made.
755        kernel_first_resume( kernelTLS.this_processor );
756
757
758
759        // THE SYSTEM IS NOW COMPLETELY RUNNING
760        __cfaabi_dbg_print_safe("Kernel : Started\n--------------------------------------------------\n\n");
761
762        verify( ! kernelTLS.preemption_state.enabled );
763        enable_interrupts( __cfaabi_dbg_ctx );
764        verify( TL_GET( preemption_state.enabled ) );
765}
766
767static void kernel_shutdown(void) {
768        __cfaabi_dbg_print_safe("\n--------------------------------------------------\nKernel : Shutting down\n");
769
770        verify( TL_GET( preemption_state.enabled ) );
771        disable_interrupts();
772        verify( ! kernelTLS.preemption_state.enabled );
773
774        // SKULLDUGGERY: Notify the mainProcessor it needs to terminates.
775        // When its coroutine terminates, it return control to the mainThread
776        // which is currently here
777        __atomic_store_n(&mainProcessor->do_terminate, true, __ATOMIC_RELEASE);
778        kernel_last_resume( kernelTLS.this_processor );
779        mainThread->self_cor.state = Halted;
780
781        // THE SYSTEM IS NOW COMPLETELY STOPPED
782
783        // Disable preemption
784        kernel_stop_preemption();
785
786        // Destroy the main processor and its context in reverse order of construction
787        // These were manually constructed so we need manually destroy them
788        ^(mainProcessor->runner){};
789        ^(mainProcessor){};
790
791        // Final step, destroy the main thread since it is no longer needed
792        // Since we provided a stack to this taxk it will not destroy anything
793        ^(mainThread){};
794
795        ^(__cfa_dbg_global_clusters.list){};
796        ^(__cfa_dbg_global_clusters.lock){};
797
798        __cfaabi_dbg_print_safe("Kernel : Shutdown complete\n");
799}
800
801//=============================================================================================
802// Kernel Quiescing
803//=============================================================================================
804static void halt(processor * this) with( *this ) {
805        // verify( ! __atomic_load_n(&do_terminate, __ATOMIC_SEQ_CST) );
806
807        with( *cltr ) {
808                lock      (proc_list_lock __cfaabi_dbg_ctx2);
809                remove    (procs, *this);
810                push_front(idles, *this);
811                unlock    (proc_list_lock);
812        }
813
814        __cfaabi_dbg_print_safe("Kernel : Processor %p ready to sleep\n", this);
815
816        wait( idleLock );
817
818        __cfaabi_dbg_print_safe("Kernel : Processor %p woke up and ready to run\n", this);
819
820        with( *cltr ) {
821                lock      (proc_list_lock __cfaabi_dbg_ctx2);
822                remove    (idles, *this);
823                push_front(procs, *this);
824                unlock    (proc_list_lock);
825        }
826}
827
828//=============================================================================================
829// Unexpected Terminating logic
830//=============================================================================================
831static __spinlock_t kernel_abort_lock;
832static bool kernel_abort_called = false;
833
834void * kernel_abort(void) __attribute__ ((__nothrow__)) {
835        // abort cannot be recursively entered by the same or different processors because all signal handlers return when
836        // the globalAbort flag is true.
837        lock( kernel_abort_lock __cfaabi_dbg_ctx2 );
838
839        // first task to abort ?
840        if ( kernel_abort_called ) {                    // not first task to abort ?
841                unlock( kernel_abort_lock );
842
843                sigset_t mask;
844                sigemptyset( &mask );
845                sigaddset( &mask, SIGALRM );            // block SIGALRM signals
846                sigaddset( &mask, SIGUSR1 );            // block SIGALRM signals
847                sigsuspend( &mask );                            // block the processor to prevent further damage during abort
848                _exit( EXIT_FAILURE );                          // if processor unblocks before it is killed, terminate it
849        }
850        else {
851                kernel_abort_called = true;
852                unlock( kernel_abort_lock );
853        }
854
855        return kernelTLS.this_thread;
856}
857
858void kernel_abort_msg( void * kernel_data, char * abort_text, int abort_text_size ) {
859        thread_desc * thrd = kernel_data;
860
861        if(thrd) {
862                int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
863                __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
864
865                if ( &thrd->self_cor != thrd->curr_cor ) {
866                        len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
867                        __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
868                }
869                else {
870                        __cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
871                }
872        }
873        else {
874                int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
875                __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
876        }
877}
878
879int kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
880        return get_coroutine(kernelTLS.this_thread) == get_coroutine(mainThread) ? 4 : 2;
881}
882
883static __spinlock_t kernel_debug_lock;
884
885extern "C" {
886        void __cfaabi_bits_acquire() {
887                lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
888        }
889
890        void __cfaabi_bits_release() {
891                unlock( kernel_debug_lock );
892        }
893}
894
895//=============================================================================================
896// Kernel Utilities
897//=============================================================================================
898//-----------------------------------------------------------------------------
899// Locks
900void  ?{}( semaphore & this, int count = 1 ) {
901        (this.lock){};
902        this.count = count;
903        (this.waiting){};
904}
905void ^?{}(semaphore & this) {}
906
907void P(semaphore & this) with( this ){
908        lock( lock __cfaabi_dbg_ctx2 );
909        count -= 1;
910        if ( count < 0 ) {
911                // queue current task
912                append( waiting, kernelTLS.this_thread );
913
914                // atomically release spin lock and block
915                BlockInternal( &lock );
916        }
917        else {
918            unlock( lock );
919        }
920}
921
922void V(semaphore & this) with( this ) {
923        thread_desc * thrd = 0p;
924        lock( lock __cfaabi_dbg_ctx2 );
925        count += 1;
926        if ( count <= 0 ) {
927                // remove task at head of waiting list
928                thrd = pop_head( waiting );
929        }
930
931        unlock( lock );
932
933        // make new owner
934        WakeThread( thrd );
935}
936
937//-----------------------------------------------------------------------------
938// Global Queues
939void doregister( cluster     & cltr ) {
940        lock      ( __cfa_dbg_global_clusters.lock __cfaabi_dbg_ctx2);
941        push_front( __cfa_dbg_global_clusters.list, cltr );
942        unlock    ( __cfa_dbg_global_clusters.lock );
943}
944
945void unregister( cluster     & cltr ) {
946        lock  ( __cfa_dbg_global_clusters.lock __cfaabi_dbg_ctx2);
947        remove( __cfa_dbg_global_clusters.list, cltr );
948        unlock( __cfa_dbg_global_clusters.lock );
949}
950
951void doregister( cluster * cltr, thread_desc & thrd ) {
952        lock      (cltr->thread_list_lock __cfaabi_dbg_ctx2);
953        cltr->nthreads += 1;
954        push_front(cltr->threads, thrd);
955        unlock    (cltr->thread_list_lock);
956}
957
958void unregister( cluster * cltr, thread_desc & thrd ) {
959        lock  (cltr->thread_list_lock __cfaabi_dbg_ctx2);
960        remove(cltr->threads, thrd );
961        cltr->nthreads -= 1;
962        unlock(cltr->thread_list_lock);
963}
964
965void doregister( cluster * cltr, processor * proc ) {
966        lock      (cltr->proc_list_lock __cfaabi_dbg_ctx2);
967        cltr->nprocessors += 1;
968        push_front(cltr->procs, *proc);
969        unlock    (cltr->proc_list_lock);
970}
971
972void unregister( cluster * cltr, processor * proc ) {
973        lock  (cltr->proc_list_lock __cfaabi_dbg_ctx2);
974        remove(cltr->procs, *proc );
975        cltr->nprocessors -= 1;
976        unlock(cltr->proc_list_lock);
977}
978
979//-----------------------------------------------------------------------------
980// Debug
981__cfaabi_dbg_debug_do(
982        extern "C" {
983                void __cfaabi_dbg_record(__spinlock_t & this, const char prev_name[]) {
984                        this.prev_name = prev_name;
985                        this.prev_thrd = kernelTLS.this_thread;
986                }
987        }
988)
989
990//-----------------------------------------------------------------------------
991// Debug
992bool threading_enabled(void) {
993        return true;
994}
995// Local Variables: //
996// mode: c //
997// tab-width: 4 //
998// End: //
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