source: libcfa/src/concurrency/kernel.cfa @ 9f575ea

arm-ehjacob/cs343-translationjenkins-sandboxnew-astnew-ast-unique-expr
Last change on this file since 9f575ea was 9f575ea, checked in by Thierry Delisle <tdelisle@…>, 22 months ago

First attempt at park/unpark

  • Property mode set to 100644
File size: 29.3 KB
Line 
1//
2// Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo
3//
4// The contents of this file are covered under the licence agreement in the
5// file "LICENCE" distributed with Cforall.
6//
7// kernel.c --
8//
9// Author           : Thierry Delisle
10// Created On       : Tue Jan 17 12:27:26 2017
11// Last Modified By : Peter A. Buhr
12// Last Modified On : Thu Jan 30 22:55:50 2020
13// Update Count     : 56
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
330        verify(proc_cor->state == Active);
331        proc_cor->state = Inactive;
332
333        // Actually run the thread
334        RUN:
335        {
336                if(unlikely(thrd_dst->preempted)) {
337                        thrd_dst->preempted = false;
338                } else {
339                        thrd_dst->state = Active;
340                }
341
342                // set context switch to the thread that the processor is executing
343                verify( thrd_dst->context.SP );
344                CtxSwitch( &proc_cor->context, &thrd_dst->context );
345                // when CtxSwitch returns we are back in the processor coroutine
346        }
347
348        // We just finished running a thread, there are a few things that could have happened.
349        // 1 - Regular case : the thread has blocked and now one has scheduled it yet.
350        // 2 - Racy case    : the thread has blocked but someone has already tried to schedule it.
351        // 3 - Polite Racy case : the thread has blocked, someone has already tried to schedule it, but the thread is nice and wants to go through the ready-queue any way
352        // 4 - Preempted
353        // In case 1, we may have won a race so we can't write to the state again.
354        // In case 2, we lost the race so we now own the thread.
355        // In case 3, we lost the race but can just reschedule the thread.
356
357        if(unlikely(thrd_dst->preempted)) {
358                // The thread was preempted, reschedule it and reset the flag
359                ScheduleThread( thrd_dst );
360
361                // Just before returning to the processor, set the processor coroutine to active
362                proc_cor->state = Active;
363                return;
364        }
365
366        // set state of processor coroutine to active and the thread to inactive
367        enum coroutine_state old_state = __atomic_exchange_n(&thrd_dst->state, Inactive, __ATOMIC_SEQ_CST);
368        switch(old_state) {
369                case Halted:
370                        // The thread has halted, it should never be scheduled/run again, leave it back to Halted and move on
371                        thrd_dst->state = Halted;
372                        break;
373                case Active:
374                        // This is case 1, the regular case, nothing more is needed
375                        break;
376                case Rerun:
377                        // This is case 2, the racy case, someone tried to run this thread before it finished blocking
378                        // In this case, just run it again.
379                        goto RUN;
380                case Reschedule:
381                        // This is case 3, someone tried to run this before it finished blocking
382                        // but it must go through the ready-queue
383                        thrd_dst->state = Inactive;  /*restore invariant */
384                        ScheduleThread( thrd_dst );
385                        break;
386                case Inactive:
387                case Start:
388                case Primed:
389                default:
390                        // This makes no sense, something is wrong abort
391                        abort("Finished running a thread that was Inactive/Start/Primed %d\n", old_state);
392        }
393
394        // Just before returning to the processor, set the processor coroutine to active
395        proc_cor->state = Active;
396}
397
398// KERNEL_ONLY
399static void returnToKernel() {
400        verify( ! kernelTLS.preemption_state.enabled );
401        coroutine_desc * proc_cor = get_coroutine(kernelTLS.this_processor->runner);
402        thread_desc * thrd_src = kernelTLS.this_thread;
403
404        // Run the thread on this processor
405        {
406                int local_errno = *__volatile_errno();
407                #if defined( __i386 ) || defined( __x86_64 )
408                        __x87_store;
409                #endif
410                verify( proc_cor->context.SP );
411                CtxSwitch( &thrd_src->context, &proc_cor->context );
412                #if defined( __i386 ) || defined( __x86_64 )
413                        __x87_load;
414                #endif
415                *__volatile_errno() = local_errno;
416        }
417
418        verify( ! kernelTLS.preemption_state.enabled );
419}
420
421// KERNEL_ONLY
422// Once a thread has finished running, some of
423// its final actions must be executed from the kernel
424static void finishRunning(processor * this) with( this->finish ) {
425        verify( ! kernelTLS.preemption_state.enabled );
426        verify( action_code == No_Action );
427        choose( action_code ) {
428        case No_Action:
429                break;
430        case Release:
431                unlock( *lock );
432        case Schedule:
433                ScheduleThread( thrd );
434        case Release_Schedule:
435                unlock( *lock );
436                ScheduleThread( thrd );
437        case Release_Multi:
438                for(int i = 0; i < lock_count; i++) {
439                        unlock( *locks[i] );
440                }
441        case Release_Multi_Schedule:
442                for(int i = 0; i < lock_count; i++) {
443                        unlock( *locks[i] );
444                }
445                for(int i = 0; i < thrd_count; i++) {
446                        ScheduleThread( thrds[i] );
447                }
448        case Callback:
449                callback();
450        default:
451                abort("KERNEL ERROR: Unexpected action to run after thread");
452        }
453}
454
455// KERNEL_ONLY
456// Context invoker for processors
457// This is the entry point for processors (kernel threads)
458// It effectively constructs a coroutine by stealing the pthread stack
459static void * CtxInvokeProcessor(void * arg) {
460        processor * proc = (processor *) arg;
461        kernelTLS.this_processor = proc;
462        kernelTLS.this_thread    = 0p;
463        kernelTLS.preemption_state.[enabled, disable_count] = [false, 1];
464        // SKULLDUGGERY: We want to create a context for the processor coroutine
465        // which is needed for the 2-step context switch. However, there is no reason
466        // to waste the perfectly valid stack create by pthread.
467        current_stack_info_t info;
468        __stack_t ctx;
469        info.storage = &ctx;
470        (proc->runner){ proc, &info };
471
472        __cfaabi_dbg_print_safe("Coroutine : created stack %p\n", get_coroutine(proc->runner)->stack.storage);
473
474        //Set global state
475        kernelTLS.this_thread = 0p;
476
477        //We now have a proper context from which to schedule threads
478        __cfaabi_dbg_print_safe("Kernel : core %p created (%p, %p)\n", proc, &proc->runner, &ctx);
479
480        // SKULLDUGGERY: Since the coroutine doesn't have its own stack, we can't
481        // resume it to start it like it normally would, it will just context switch
482        // back to here. Instead directly call the main since we already are on the
483        // appropriate stack.
484        get_coroutine(proc->runner)->state = Active;
485        main( proc->runner );
486        get_coroutine(proc->runner)->state = Halted;
487
488        // Main routine of the core returned, the core is now fully terminated
489        __cfaabi_dbg_print_safe("Kernel : core %p main ended (%p)\n", proc, &proc->runner);
490
491        return 0p;
492}
493
494static void Abort( int ret, const char * func ) {
495        if ( ret ) {                                                                            // pthread routines return errno values
496                abort( "%s : internal error, error(%d) %s.", func, ret, strerror( ret ) );
497        } // if
498} // Abort
499
500void * create_pthread( pthread_t * pthread, void * (*start)(void *), void * arg ) {
501        pthread_attr_t attr;
502
503        Abort( pthread_attr_init( &attr ), "pthread_attr_init" ); // initialize attribute
504
505        size_t stacksize;
506        // default stack size, normally defined by shell limit
507        Abort( pthread_attr_getstacksize( &attr, &stacksize ), "pthread_attr_getstacksize" );
508        assert( stacksize >= PTHREAD_STACK_MIN );
509
510        void * stack;
511        __cfaabi_dbg_debug_do(
512                stack = memalign( __page_size, stacksize + __page_size );
513                // pthread has no mechanism to create the guard page in user supplied stack.
514                if ( mprotect( stack, __page_size, PROT_NONE ) == -1 ) {
515                        abort( "mprotect : internal error, mprotect failure, error(%d) %s.", errno, strerror( errno ) );
516                } // if
517        );
518        __cfaabi_dbg_no_debug_do(
519                stack = malloc( stacksize );
520        );
521
522        Abort( pthread_attr_setstack( &attr, stack, stacksize ), "pthread_attr_setstack" );
523
524        Abort( pthread_create( pthread, &attr, start, arg ), "pthread_create" );
525        return stack;
526}
527
528static void start(processor * this) {
529        __cfaabi_dbg_print_safe("Kernel : Starting core %p\n", this);
530
531        this->stack = create_pthread( &this->kernel_thread, CtxInvokeProcessor, (void *)this );
532
533        __cfaabi_dbg_print_safe("Kernel : core %p started\n", this);
534}
535
536// KERNEL_ONLY
537void kernel_first_resume( processor * this ) {
538        thread_desc * src = mainThread;
539        coroutine_desc * dst = get_coroutine(this->runner);
540
541        verify( ! kernelTLS.preemption_state.enabled );
542
543        kernelTLS.this_thread->curr_cor = dst;
544        __stack_prepare( &dst->stack, 65000 );
545        CtxStart(main, dst, this->runner, CtxInvokeCoroutine);
546
547        verify( ! kernelTLS.preemption_state.enabled );
548
549        dst->last = &src->self_cor;
550        dst->starter = dst->starter ? dst->starter : &src->self_cor;
551
552        // set state of current coroutine to inactive
553        src->state = src->state == Halted ? Halted : Inactive;
554
555        // context switch to specified coroutine
556        verify( dst->context.SP );
557        CtxSwitch( &src->context, &dst->context );
558        // when CtxSwitch returns we are back in the src coroutine
559
560        mainThread->curr_cor = &mainThread->self_cor;
561
562        // set state of new coroutine to active
563        src->state = Active;
564
565        verify( ! kernelTLS.preemption_state.enabled );
566}
567
568// KERNEL_ONLY
569void kernel_last_resume( processor * this ) {
570        coroutine_desc * src = &mainThread->self_cor;
571        coroutine_desc * dst = get_coroutine(this->runner);
572
573        verify( ! kernelTLS.preemption_state.enabled );
574        verify( dst->starter == src );
575        verify( dst->context.SP );
576
577        // context switch to the processor
578        CtxSwitch( &src->context, &dst->context );
579}
580
581//-----------------------------------------------------------------------------
582// Scheduler routines
583
584// KERNEL ONLY
585void ScheduleThread( thread_desc * thrd ) with( *thrd->curr_cluster ) {
586        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
587        /* paranoid */ verifyf( thrd->state == Inactive || thrd->state == Start || thrd->preempted, "state : %d, preempted %d\n", thrd->state, thrd->preempted);
588        /* paranoid */ verifyf( thrd->next == 0p, "Expected null got %p", thrd->next );
589
590        lock  ( ready_queue_lock __cfaabi_dbg_ctx2 );
591        bool was_empty = !(ready_queue != 0);
592        append( ready_queue, thrd );
593        unlock( ready_queue_lock );
594
595        if(was_empty) {
596                lock      (proc_list_lock __cfaabi_dbg_ctx2);
597                if(idles) {
598                        wake_fast(idles.head);
599                }
600                unlock    (proc_list_lock);
601        }
602        else if( struct processor * idle = idles.head ) {
603                wake_fast(idle);
604        }
605
606        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
607}
608
609// KERNEL ONLY
610thread_desc * nextThread(cluster * this) with( *this ) {
611        verify( ! kernelTLS.preemption_state.enabled );
612        lock( ready_queue_lock __cfaabi_dbg_ctx2 );
613        thread_desc * head = pop_head( ready_queue );
614        unlock( ready_queue_lock );
615        verify( ! kernelTLS.preemption_state.enabled );
616        return head;
617}
618
619void BlockInternal() {
620        disable_interrupts();
621        verify( ! kernelTLS.preemption_state.enabled );
622        returnToKernel();
623        verify( ! kernelTLS.preemption_state.enabled );
624        enable_interrupts( __cfaabi_dbg_ctx );
625}
626
627void BlockInternal( __spinlock_t * lock ) {
628        disable_interrupts();
629        unlock( *lock );
630
631        verify( ! kernelTLS.preemption_state.enabled );
632        returnToKernel();
633        verify( ! kernelTLS.preemption_state.enabled );
634
635        enable_interrupts( __cfaabi_dbg_ctx );
636}
637
638void BlockInternal( thread_desc * thrd ) {
639        disable_interrupts();
640        WakeThread( thrd, false );
641
642        verify( ! kernelTLS.preemption_state.enabled );
643        returnToKernel();
644        verify( ! kernelTLS.preemption_state.enabled );
645
646        enable_interrupts( __cfaabi_dbg_ctx );
647}
648
649void BlockInternal( __spinlock_t * lock, thread_desc * thrd ) {
650        disable_interrupts();
651        unlock( *lock );
652        WakeThread( thrd, false );
653
654        verify( ! kernelTLS.preemption_state.enabled );
655        returnToKernel();
656        verify( ! kernelTLS.preemption_state.enabled );
657
658        enable_interrupts( __cfaabi_dbg_ctx );
659}
660
661void BlockInternal(__spinlock_t * locks [], unsigned short count) {
662        disable_interrupts();
663        for(int i = 0; i < count; i++) {
664                unlock( *locks[i] );
665        }
666
667        verify( ! kernelTLS.preemption_state.enabled );
668        returnToKernel();
669        verify( ! kernelTLS.preemption_state.enabled );
670
671        enable_interrupts( __cfaabi_dbg_ctx );
672}
673
674void BlockInternal(__spinlock_t * locks [], unsigned short lock_count, thread_desc * thrds [], unsigned short thrd_count) {
675        disable_interrupts();
676        for(int i = 0; i < lock_count; i++) {
677                unlock( *locks[i] );
678        }
679        for(int i = 0; i < thrd_count; i++) {
680                WakeThread( thrds[i], false );
681        }
682
683        verify( ! kernelTLS.preemption_state.enabled );
684        returnToKernel();
685        verify( ! kernelTLS.preemption_state.enabled );
686
687        enable_interrupts( __cfaabi_dbg_ctx );
688}
689
690void BlockInternal(__finish_callback_fptr_t callback) {
691        disable_interrupts();
692        callback();
693
694        verify( ! kernelTLS.preemption_state.enabled );
695        returnToKernel();
696        verify( ! kernelTLS.preemption_state.enabled );
697
698        enable_interrupts( __cfaabi_dbg_ctx );
699}
700
701// KERNEL ONLY
702void LeaveThread(__spinlock_t * lock, thread_desc * thrd) {
703        verify( ! kernelTLS.preemption_state.enabled );
704        unlock( *lock );
705        WakeThread( thrd, false );
706
707        returnToKernel();
708}
709
710//=============================================================================================
711// Kernel Setup logic
712//=============================================================================================
713//-----------------------------------------------------------------------------
714// Kernel boot procedures
715static void kernel_startup(void) {
716        verify( ! kernelTLS.preemption_state.enabled );
717        __cfaabi_dbg_print_safe("Kernel : Starting\n");
718
719        __page_size = sysconf( _SC_PAGESIZE );
720
721        __cfa_dbg_global_clusters.list{ __get };
722        __cfa_dbg_global_clusters.lock{};
723
724        // Initialize the main cluster
725        mainCluster = (cluster *)&storage_mainCluster;
726        (*mainCluster){"Main Cluster"};
727
728        __cfaabi_dbg_print_safe("Kernel : Main cluster ready\n");
729
730        // Start by initializing the main thread
731        // SKULLDUGGERY: the mainThread steals the process main thread
732        // which will then be scheduled by the mainProcessor normally
733        mainThread = (thread_desc *)&storage_mainThread;
734        current_stack_info_t info;
735        info.storage = (__stack_t*)&storage_mainThreadCtx;
736        (*mainThread){ &info };
737
738        __cfaabi_dbg_print_safe("Kernel : Main thread ready\n");
739
740
741
742        // Construct the processor context of the main processor
743        void ?{}(processorCtx_t & this, processor * proc) {
744                (this.__cor){ "Processor" };
745                this.__cor.starter = 0p;
746                this.proc = proc;
747        }
748
749        void ?{}(processor & this) with( this ) {
750                name = "Main Processor";
751                cltr = mainCluster;
752                terminated{ 0 };
753                do_terminate = false;
754                preemption_alarm = 0p;
755                pending_preemption = false;
756                kernel_thread = pthread_self();
757
758                runner{ &this };
759                __cfaabi_dbg_print_safe("Kernel : constructed main processor context %p\n", &runner);
760        }
761
762        // Initialize the main processor and the main processor ctx
763        // (the coroutine that contains the processing control flow)
764        mainProcessor = (processor *)&storage_mainProcessor;
765        (*mainProcessor){};
766
767        //initialize the global state variables
768        kernelTLS.this_processor = mainProcessor;
769        kernelTLS.this_thread    = mainThread;
770
771        // Enable preemption
772        kernel_start_preemption();
773
774        // Add the main thread to the ready queue
775        // once resume is called on mainProcessor->runner the mainThread needs to be scheduled like any normal thread
776        ScheduleThread(mainThread);
777
778        // SKULLDUGGERY: Force a context switch to the main processor to set the main thread's context to the current UNIX
779        // context. Hence, the main thread does not begin through CtxInvokeThread, like all other threads. The trick here is that
780        // mainThread is on the ready queue when this call is made.
781        kernel_first_resume( kernelTLS.this_processor );
782
783
784
785        // THE SYSTEM IS NOW COMPLETELY RUNNING
786        __cfaabi_dbg_print_safe("Kernel : Started\n--------------------------------------------------\n\n");
787
788        verify( ! kernelTLS.preemption_state.enabled );
789        enable_interrupts( __cfaabi_dbg_ctx );
790        verify( TL_GET( preemption_state.enabled ) );
791}
792
793static void kernel_shutdown(void) {
794        __cfaabi_dbg_print_safe("\n--------------------------------------------------\nKernel : Shutting down\n");
795
796        verify( TL_GET( preemption_state.enabled ) );
797        disable_interrupts();
798        verify( ! kernelTLS.preemption_state.enabled );
799
800        // SKULLDUGGERY: Notify the mainProcessor it needs to terminates.
801        // When its coroutine terminates, it return control to the mainThread
802        // which is currently here
803        __atomic_store_n(&mainProcessor->do_terminate, true, __ATOMIC_RELEASE);
804        kernel_last_resume( kernelTLS.this_processor );
805        mainThread->self_cor.state = Halted;
806
807        // THE SYSTEM IS NOW COMPLETELY STOPPED
808
809        // Disable preemption
810        kernel_stop_preemption();
811
812        // Destroy the main processor and its context in reverse order of construction
813        // These were manually constructed so we need manually destroy them
814        ^(mainProcessor->runner){};
815        ^(mainProcessor){};
816
817        // Final step, destroy the main thread since it is no longer needed
818        // Since we provided a stack to this taxk it will not destroy anything
819        ^(mainThread){};
820
821        ^(__cfa_dbg_global_clusters.list){};
822        ^(__cfa_dbg_global_clusters.lock){};
823
824        __cfaabi_dbg_print_safe("Kernel : Shutdown complete\n");
825}
826
827//=============================================================================================
828// Kernel Quiescing
829//=============================================================================================
830static void halt(processor * this) with( *this ) {
831        // verify( ! __atomic_load_n(&do_terminate, __ATOMIC_SEQ_CST) );
832
833        with( *cltr ) {
834                lock      (proc_list_lock __cfaabi_dbg_ctx2);
835                remove    (procs, *this);
836                push_front(idles, *this);
837                unlock    (proc_list_lock);
838        }
839
840        __cfaabi_dbg_print_safe("Kernel : Processor %p ready to sleep\n", this);
841
842        wait( idleLock );
843
844        __cfaabi_dbg_print_safe("Kernel : Processor %p woke up and ready to run\n", this);
845
846        with( *cltr ) {
847                lock      (proc_list_lock __cfaabi_dbg_ctx2);
848                remove    (idles, *this);
849                push_front(procs, *this);
850                unlock    (proc_list_lock);
851        }
852}
853
854//=============================================================================================
855// Unexpected Terminating logic
856//=============================================================================================
857static __spinlock_t kernel_abort_lock;
858static bool kernel_abort_called = false;
859
860void * kernel_abort(void) __attribute__ ((__nothrow__)) {
861        // abort cannot be recursively entered by the same or different processors because all signal handlers return when
862        // the globalAbort flag is true.
863        lock( kernel_abort_lock __cfaabi_dbg_ctx2 );
864
865        // first task to abort ?
866        if ( kernel_abort_called ) {                    // not first task to abort ?
867                unlock( kernel_abort_lock );
868
869                sigset_t mask;
870                sigemptyset( &mask );
871                sigaddset( &mask, SIGALRM );            // block SIGALRM signals
872                sigaddset( &mask, SIGUSR1 );            // block SIGALRM signals
873                sigsuspend( &mask );                            // block the processor to prevent further damage during abort
874                _exit( EXIT_FAILURE );                          // if processor unblocks before it is killed, terminate it
875        }
876        else {
877                kernel_abort_called = true;
878                unlock( kernel_abort_lock );
879        }
880
881        return kernelTLS.this_thread;
882}
883
884void kernel_abort_msg( void * kernel_data, char * abort_text, int abort_text_size ) {
885        thread_desc * thrd = kernel_data;
886
887        if(thrd) {
888                int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
889                __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
890
891                if ( &thrd->self_cor != thrd->curr_cor ) {
892                        len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
893                        __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
894                }
895                else {
896                        __cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
897                }
898        }
899        else {
900                int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
901                __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
902        }
903}
904
905int kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
906        return get_coroutine(kernelTLS.this_thread) == get_coroutine(mainThread) ? 4 : 2;
907}
908
909static __spinlock_t kernel_debug_lock;
910
911extern "C" {
912        void __cfaabi_bits_acquire() {
913                lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
914        }
915
916        void __cfaabi_bits_release() {
917                unlock( kernel_debug_lock );
918        }
919}
920
921//=============================================================================================
922// Kernel Utilities
923//=============================================================================================
924//-----------------------------------------------------------------------------
925// Locks
926void  ?{}( semaphore & this, int count = 1 ) {
927        (this.lock){};
928        this.count = count;
929        (this.waiting){};
930}
931void ^?{}(semaphore & this) {}
932
933void P(semaphore & this) with( this ){
934        lock( lock __cfaabi_dbg_ctx2 );
935        count -= 1;
936        if ( count < 0 ) {
937                // queue current task
938                append( waiting, kernelTLS.this_thread );
939
940                // atomically release spin lock and block
941                BlockInternal( &lock );
942        }
943        else {
944            unlock( lock );
945        }
946}
947
948void V(semaphore & this) with( this ) {
949        thread_desc * thrd = 0p;
950        lock( lock __cfaabi_dbg_ctx2 );
951        count += 1;
952        if ( count <= 0 ) {
953                // remove task at head of waiting list
954                thrd = pop_head( waiting );
955        }
956
957        unlock( lock );
958
959        // make new owner
960        WakeThread( thrd, false );
961}
962
963//-----------------------------------------------------------------------------
964// Global Queues
965void doregister( cluster     & cltr ) {
966        lock      ( __cfa_dbg_global_clusters.lock __cfaabi_dbg_ctx2);
967        push_front( __cfa_dbg_global_clusters.list, cltr );
968        unlock    ( __cfa_dbg_global_clusters.lock );
969}
970
971void unregister( cluster     & cltr ) {
972        lock  ( __cfa_dbg_global_clusters.lock __cfaabi_dbg_ctx2);
973        remove( __cfa_dbg_global_clusters.list, cltr );
974        unlock( __cfa_dbg_global_clusters.lock );
975}
976
977void doregister( cluster * cltr, thread_desc & thrd ) {
978        lock      (cltr->thread_list_lock __cfaabi_dbg_ctx2);
979        cltr->nthreads += 1;
980        push_front(cltr->threads, thrd);
981        unlock    (cltr->thread_list_lock);
982}
983
984void unregister( cluster * cltr, thread_desc & thrd ) {
985        lock  (cltr->thread_list_lock __cfaabi_dbg_ctx2);
986        remove(cltr->threads, thrd );
987        cltr->nthreads -= 1;
988        unlock(cltr->thread_list_lock);
989}
990
991void doregister( cluster * cltr, processor * proc ) {
992        lock      (cltr->proc_list_lock __cfaabi_dbg_ctx2);
993        cltr->nprocessors += 1;
994        push_front(cltr->procs, *proc);
995        unlock    (cltr->proc_list_lock);
996}
997
998void unregister( cluster * cltr, processor * proc ) {
999        lock  (cltr->proc_list_lock __cfaabi_dbg_ctx2);
1000        remove(cltr->procs, *proc );
1001        cltr->nprocessors -= 1;
1002        unlock(cltr->proc_list_lock);
1003}
1004
1005//-----------------------------------------------------------------------------
1006// Debug
1007__cfaabi_dbg_debug_do(
1008        extern "C" {
1009                void __cfaabi_dbg_record(__spinlock_t & this, const char * prev_name) {
1010                        this.prev_name = prev_name;
1011                        this.prev_thrd = kernelTLS.this_thread;
1012                }
1013        }
1014)
1015
1016//-----------------------------------------------------------------------------
1017// Debug
1018bool threading_enabled(void) {
1019        return true;
1020}
1021// Local Variables: //
1022// mode: c //
1023// tab-width: 4 //
1024// End: //
Note: See TracBrowser for help on using the repository browser.