source: libcfa/src/concurrency/kernel.cfa @ 58688bf

arm-ehjacob/cs343-translationnew-ast-unique-expr
Last change on this file since 58688bf was 58688bf, checked in by Thierry Delisle <tdelisle@…>, 13 months ago

Added assertion to check there aren't pending unparks

  • Property mode set to 100644
File size: 23.1 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 : Mon Aug 31 07:08:20 2020
13// Update Count     : 71
14//
15
16#define __cforall_thread__
17// #define __CFA_DEBUG_PRINT_RUNTIME_CORE__
18
19//C Includes
20#include <errno.h>
21#include <stdio.h>
22#include <signal.h>
23#include <unistd.h>
24
25//CFA Includes
26#include "kernel_private.hfa"
27#include "preemption.hfa"
28
29//Private includes
30#define __CFA_INVOKE_PRIVATE__
31#include "invoke.h"
32
33
34//-----------------------------------------------------------------------------
35// Some assembly required
36#if defined( __i386 )
37        // mxcr : SSE Status and Control bits (control bits are preserved across function calls)
38        // fcw  : X87 FPU control word (preserved across function calls)
39        #define __x87_store         \
40                uint32_t __mxcr;      \
41                uint16_t __fcw;       \
42                __asm__ volatile (    \
43                        "stmxcsr %0\n"  \
44                        "fnstcw  %1\n"  \
45                        : "=m" (__mxcr),\
46                                "=m" (__fcw)  \
47                )
48
49        #define __x87_load         \
50                __asm__ volatile (   \
51                        "fldcw  %1\n"  \
52                        "ldmxcsr %0\n" \
53                        ::"m" (__mxcr),\
54                                "m" (__fcw)  \
55                )
56
57#elif defined( __x86_64 )
58        #define __x87_store         \
59                uint32_t __mxcr;      \
60                uint16_t __fcw;       \
61                __asm__ volatile (    \
62                        "stmxcsr %0\n"  \
63                        "fnstcw  %1\n"  \
64                        : "=m" (__mxcr),\
65                                "=m" (__fcw)  \
66                )
67
68        #define __x87_load          \
69                __asm__ volatile (    \
70                        "fldcw  %1\n"   \
71                        "ldmxcsr %0\n"  \
72                        :: "m" (__mxcr),\
73                                "m" (__fcw)  \
74                )
75
76#elif defined( __arm__ )
77        #define __x87_store
78        #define __x87_load
79
80#elif defined( __aarch64__ )
81        #define __x87_store              \
82                uint32_t __fpcntl[2];    \
83                __asm__ volatile (    \
84                        "mrs x9, FPCR\n" \
85                        "mrs x10, FPSR\n"  \
86                        "stp x9, x10, %0\n"  \
87                        : "=m" (__fpcntl) : : "x9", "x10" \
88                )
89
90        #define __x87_load         \
91                __asm__ volatile (    \
92                        "ldp x9, x10, %0\n"  \
93                        "msr FPSR, x10\n"  \
94                        "msr FPCR, x9\n" \
95                : "=m" (__fpcntl) : : "x9", "x10" \
96                )
97
98#else
99        #error unsupported hardware architecture
100#endif
101
102extern $thread * mainThread;
103extern processor * mainProcessor;
104
105//-----------------------------------------------------------------------------
106// Kernel Scheduling logic
107static $thread * __next_thread(cluster * this);
108static $thread * __next_thread_slow(cluster * this);
109static void __run_thread(processor * this, $thread * dst);
110static void __wake_one(cluster * cltr);
111
112static void push  (__cluster_idles & idles, processor & proc);
113static void remove(__cluster_idles & idles, processor & proc);
114static [unsigned idle, unsigned total, * processor] query( & __cluster_idles idles );
115
116
117//=============================================================================================
118// Kernel Scheduling logic
119//=============================================================================================
120//Main of the processor contexts
121void main(processorCtx_t & runner) {
122        // Because of a bug, we couldn't initialized the seed on construction
123        // Do it here
124        kernelTLS.rand_seed ^= rdtscl();
125        kernelTLS.ready_rng.fwd_seed = 25214903917_l64u * (rdtscl() ^ (uintptr_t)&runner);
126        __tls_rand_advance_bck();
127
128        processor * this = runner.proc;
129        verify(this);
130
131        __cfadbg_print_safe(runtime_core, "Kernel : core %p starting\n", this);
132        #if !defined(__CFA_NO_STATISTICS__)
133                if( this->print_halts ) {
134                        __cfaabi_bits_print_safe( STDOUT_FILENO, "Processor : %d - %s (%p)\n", this->id, this->name, (void*)this);
135                }
136        #endif
137
138        {
139                // Setup preemption data
140                preemption_scope scope = { this };
141
142                __cfadbg_print_safe(runtime_core, "Kernel : core %p started\n", this);
143
144                $thread * readyThread = 0p;
145                MAIN_LOOP:
146                for() {
147                        // Try to get the next thread
148                        readyThread = __next_thread( this->cltr );
149
150                        if( !readyThread ) {
151                                readyThread = __next_thread_slow( this->cltr );
152                        }
153
154                        HALT:
155                        if( !readyThread ) {
156                                // Don't block if we are done
157                                if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
158
159                                #if !defined(__CFA_NO_STATISTICS__)
160                                        __tls_stats()->ready.sleep.halts++;
161                                #endif
162
163                                // Push self to idle stack
164                                push(this->cltr->idles, * this);
165
166                                // Confirm the ready-queue is empty
167                                readyThread = __next_thread_slow( this->cltr );
168                                if( readyThread ) {
169                                        // A thread was found, cancel the halt
170                                        remove(this->cltr->idles, * this);
171
172                                        #if !defined(__CFA_NO_STATISTICS__)
173                                                __tls_stats()->ready.sleep.cancels++;
174                                        #endif
175
176                                        // continue the mai loop
177                                        break HALT;
178                                }
179
180                                #if !defined(__CFA_NO_STATISTICS__)
181                                        if(this->print_halts) {
182                                                __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 0\n", this->id, rdtscl());
183                                        }
184                                #endif
185
186                                wait( this->idle );
187
188                                #if !defined(__CFA_NO_STATISTICS__)
189                                        if(this->print_halts) {
190                                                __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 1\n", this->id, rdtscl());
191                                        }
192                                #endif
193
194                                // We were woken up, remove self from idle
195                                remove(this->cltr->idles, * this);
196
197                                // DON'T just proceed, start looking again
198                                continue MAIN_LOOP;
199                        }
200
201                        /* paranoid */ verify( readyThread );
202
203                        // We found a thread run it
204                        __run_thread(this, readyThread);
205
206                        // Are we done?
207                        if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
208                }
209
210                __cfadbg_print_safe(runtime_core, "Kernel : core %p stopping\n", this);
211        }
212
213        V( this->terminated );
214
215        if(this == mainProcessor) {
216                // HACK : the coroutine context switch expects this_thread to be set
217                // and it make sense for it to be set in all other cases except here
218                // fake it
219                kernelTLS.this_thread = mainThread;
220        }
221
222        __cfadbg_print_safe(runtime_core, "Kernel : core %p terminated\n", this);
223}
224
225static int * __volatile_errno() __attribute__((noinline));
226static int * __volatile_errno() { asm(""); return &errno; }
227
228// KERNEL ONLY
229// runThread runs a thread by context switching
230// from the processor coroutine to the target thread
231static void __run_thread(processor * this, $thread * thrd_dst) {
232        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
233        /* paranoid */ verifyf( thrd_dst->state == Ready || thrd_dst->preempted != __NO_PREEMPTION, "state : %d, preempted %d\n", thrd_dst->state, thrd_dst->preempted);
234        /* paranoid */ verifyf( thrd_dst->link.next == 0p, "Expected null got %p", thrd_dst->link.next );
235        __builtin_prefetch( thrd_dst->context.SP );
236
237        $coroutine * proc_cor = get_coroutine(this->runner);
238
239        // set state of processor coroutine to inactive
240        verify(proc_cor->state == Active);
241        proc_cor->state = Blocked;
242
243        // Actually run the thread
244        RUNNING:  while(true) {
245                thrd_dst->preempted = __NO_PREEMPTION;
246                thrd_dst->state = Active;
247
248                // Update global state
249                kernelTLS.this_thread = thrd_dst;
250
251                /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
252                /* paranoid */ verify( kernelTLS.this_thread == thrd_dst );
253                /* paranoid */ verify( thrd_dst->context.SP );
254                /* paranoid */ verify( thrd_dst->state != Halted );
255                /* paranoid */ verifyf( ((uintptr_t)thrd_dst->context.SP) < ((uintptr_t)__get_stack(thrd_dst->curr_cor)->base ) || thrd_dst->curr_cor == proc_cor, "ERROR : Destination $thread %p has been corrupted.\n StackPointer too small.\n", thrd_dst ); // add escape condition if we are setting up the processor
256                /* paranoid */ verifyf( ((uintptr_t)thrd_dst->context.SP) > ((uintptr_t)__get_stack(thrd_dst->curr_cor)->limit) || thrd_dst->curr_cor == proc_cor, "ERROR : Destination $thread %p has been corrupted.\n StackPointer too large.\n", thrd_dst ); // add escape condition if we are setting up the processor
257                /* paranoid */ verify( 0x0D15EA5E0D15EA5E == thrd_dst->canary );
258
259
260
261                // set context switch to the thread that the processor is executing
262                __cfactx_switch( &proc_cor->context, &thrd_dst->context );
263                // when __cfactx_switch returns we are back in the processor coroutine
264
265                /* paranoid */ verify( 0x0D15EA5E0D15EA5E == thrd_dst->canary );
266                /* paranoid */ verifyf( ((uintptr_t)thrd_dst->context.SP) > ((uintptr_t)__get_stack(thrd_dst->curr_cor)->limit), "ERROR : Destination $thread %p has been corrupted.\n StackPointer too large.\n", thrd_dst );
267                /* paranoid */ verifyf( ((uintptr_t)thrd_dst->context.SP) < ((uintptr_t)__get_stack(thrd_dst->curr_cor)->base ), "ERROR : Destination $thread %p has been corrupted.\n StackPointer too small.\n", thrd_dst );
268                /* paranoid */ verify( thrd_dst->context.SP );
269                /* paranoid */ verify( kernelTLS.this_thread == thrd_dst );
270                /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
271
272                // Reset global state
273                kernelTLS.this_thread = 0p;
274
275                // We just finished running a thread, there are a few things that could have happened.
276                // 1 - Regular case : the thread has blocked and now one has scheduled it yet.
277                // 2 - Racy case    : the thread has blocked but someone has already tried to schedule it.
278                // 4 - Preempted
279                // In case 1, we may have won a race so we can't write to the state again.
280                // In case 2, we lost the race so we now own the thread.
281
282                if(unlikely(thrd_dst->preempted != __NO_PREEMPTION)) {
283                        // The thread was preempted, reschedule it and reset the flag
284                        __schedule_thread( thrd_dst );
285                        break RUNNING;
286                }
287
288                if(unlikely(thrd_dst->state == Halted)) {
289                        // The thread has halted, it should never be scheduled/run again
290                        // finish the thread
291                        __thread_finish( thrd_dst );
292                        break RUNNING;
293                }
294
295                /* paranoid */ verify( thrd_dst->state == Active );
296                thrd_dst->state = Blocked;
297
298                // set state of processor coroutine to active and the thread to inactive
299                int old_ticket = __atomic_fetch_sub(&thrd_dst->ticket, 1, __ATOMIC_SEQ_CST);
300                switch(old_ticket) {
301                        case TICKET_RUNNING:
302                                // This is case 1, the regular case, nothing more is needed
303                                break RUNNING;
304                        case TICKET_UNBLOCK:
305                                // This is case 2, the racy case, someone tried to run this thread before it finished blocking
306                                // In this case, just run it again.
307                                continue RUNNING;
308                        default:
309                                // This makes no sense, something is wrong abort
310                                abort();
311                }
312        }
313
314        // Just before returning to the processor, set the processor coroutine to active
315        proc_cor->state = Active;
316
317        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
318}
319
320// KERNEL_ONLY
321void returnToKernel() {
322        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
323        $coroutine * proc_cor = get_coroutine(kernelTLS.this_processor->runner);
324        $thread * thrd_src = kernelTLS.this_thread;
325
326        #if !defined(__CFA_NO_STATISTICS__)
327                struct processor * last_proc = kernelTLS.this_processor;
328        #endif
329
330        // Run the thread on this processor
331        {
332                int local_errno = *__volatile_errno();
333                #if defined( __i386 ) || defined( __x86_64 )
334                        __x87_store;
335                #endif
336                /* paranoid */ verify( proc_cor->context.SP );
337                /* paranoid */ verify( 0x0D15EA5E0D15EA5E == thrd_src->canary );
338                __cfactx_switch( &thrd_src->context, &proc_cor->context );
339                /* paranoid */ verify( 0x0D15EA5E0D15EA5E == thrd_src->canary );
340                #if defined( __i386 ) || defined( __x86_64 )
341                        __x87_load;
342                #endif
343                *__volatile_errno() = local_errno;
344        }
345
346        #if !defined(__CFA_NO_STATISTICS__)
347                if(last_proc != kernelTLS.this_processor) {
348                        __tls_stats()->ready.threads.migration++;
349                }
350        #endif
351
352        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
353        /* paranoid */ verifyf( ((uintptr_t)thrd_src->context.SP) < ((uintptr_t)__get_stack(thrd_src->curr_cor)->base ), "ERROR : Returning $thread %p has been corrupted.\n StackPointer too small.\n", thrd_src );
354        /* paranoid */ verifyf( ((uintptr_t)thrd_src->context.SP) > ((uintptr_t)__get_stack(thrd_src->curr_cor)->limit), "ERROR : Returning $thread %p has been corrupted.\n StackPointer too large.\n", thrd_src );
355}
356
357//-----------------------------------------------------------------------------
358// Scheduler routines
359// KERNEL ONLY
360void __schedule_thread( $thread * thrd ) {
361        /* paranoid */ verify( thrd );
362        /* paranoid */ verify( thrd->state != Halted );
363        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
364        /* paranoid */ verify( kernelTLS.this_proc_id );
365        /* paranoid */ #if defined( __CFA_WITH_VERIFY__ )
366        /* paranoid */  if( thrd->state == Blocked || thrd->state == Start ) assertf( thrd->preempted == __NO_PREEMPTION,
367                                        "Error inactive thread marked as preempted, state %d, preemption %d\n", thrd->state, thrd->preempted );
368        /* paranoid */  if( thrd->preempted != __NO_PREEMPTION ) assertf(thrd->state == Active,
369                                        "Error preempted thread marked as not currently running, state %d, preemption %d\n", thrd->state, thrd->preempted );
370        /* paranoid */ #endif
371        /* paranoid */ verifyf( thrd->link.next == 0p, "Expected null got %p", thrd->link.next );
372        /* paranoid */ verify( 0x0D15EA5E0D15EA5E == thrd->canary );
373
374
375        if (thrd->preempted == __NO_PREEMPTION) thrd->state = Ready;
376
377        ready_schedule_lock();
378                push( thrd->curr_cluster, thrd );
379                __wake_one(thrd->curr_cluster);
380        ready_schedule_unlock();
381
382        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
383}
384
385// KERNEL ONLY
386static inline $thread * __next_thread(cluster * this) with( *this ) {
387        /* paranoid */ verify( kernelTLS.this_proc_id );
388        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
389
390        ready_schedule_lock();
391                $thread * thrd = pop( this );
392        ready_schedule_unlock();
393
394        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
395        /* paranoid */ verify( kernelTLS.this_proc_id );
396        return thrd;
397}
398
399// KERNEL ONLY
400static inline $thread * __next_thread_slow(cluster * this) with( *this ) {
401        /* paranoid */ verify( kernelTLS.this_proc_id );
402        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
403
404        ready_schedule_lock();
405                $thread * thrd = pop_slow( this );
406        ready_schedule_unlock();
407
408        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
409        /* paranoid */ verify( kernelTLS.this_proc_id );
410        return thrd;
411}
412
413void unpark( $thread * thrd ) {
414        if( !thrd ) return;
415
416        /* paranoid */ verify( kernelTLS.this_proc_id );
417        bool full = kernelTLS.this_proc_id->full_proc;
418        if(full) disable_interrupts();
419
420        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
421        int old_ticket = __atomic_fetch_add(&thrd->ticket, 1, __ATOMIC_SEQ_CST);
422        switch(old_ticket) {
423                case TICKET_RUNNING:
424                        // Wake won the race, the thread will reschedule/rerun itself
425                        break;
426                case TICKET_BLOCKED:
427                        /* paranoid */ verify( ! thrd->preempted != __NO_PREEMPTION );
428                        /* paranoid */ verify( thrd->state == Blocked );
429
430                        // Wake lost the race,
431                        __schedule_thread( thrd );
432                        break;
433                default:
434                        // This makes no sense, something is wrong abort
435                        abort("Thread %p (%s) has mismatch park/unpark\n", thrd, thrd->self_cor.name);
436        }
437        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
438
439        if(full) enable_interrupts( __cfaabi_dbg_ctx );
440        /* paranoid */ verify( kernelTLS.this_proc_id );
441}
442
443void park( void ) {
444        /* paranoid */ verify( kernelTLS.preemption_state.enabled );
445        disable_interrupts();
446        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
447        /* paranoid */ verify( kernelTLS.this_thread->preempted == __NO_PREEMPTION );
448
449        returnToKernel();
450
451        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
452        enable_interrupts( __cfaabi_dbg_ctx );
453        /* paranoid */ verify( kernelTLS.preemption_state.enabled );
454
455}
456
457extern "C" {
458        // Leave the thread monitor
459        // last routine called by a thread.
460        // Should never return
461        void __cfactx_thrd_leave() {
462                $thread * thrd = TL_GET( this_thread );
463                $monitor * this = &thrd->self_mon;
464
465                // Lock the monitor now
466                lock( this->lock __cfaabi_dbg_ctx2 );
467
468                disable_interrupts();
469
470                thrd->state = Halted;
471                if( TICKET_RUNNING != thrd->ticket ) { abort( "Thread terminated with pending unpark" ); }
472                if( thrd != this->owner || this->recursion != 1) { abort( "Thread internal monitor has unbalanced recursion" ); }
473
474                // Leave the thread
475                /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
476                returnToKernel();
477                abort();
478
479                // Control flow should never reach here!
480        }
481}
482
483// KERNEL ONLY
484bool force_yield( __Preemption_Reason reason ) {
485        /* paranoid */ verify( kernelTLS.preemption_state.enabled );
486        disable_interrupts();
487        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
488
489        $thread * thrd = kernelTLS.this_thread;
490        /* paranoid */ verify(thrd->state == Active);
491
492        // SKULLDUGGERY: It is possible that we are preempting this thread just before
493        // it was going to park itself. If that is the case and it is already using the
494        // intrusive fields then we can't use them to preempt the thread
495        // If that is the case, abandon the preemption.
496        bool preempted = false;
497        if(thrd->link.next == 0p) {
498                preempted = true;
499                thrd->preempted = reason;
500                returnToKernel();
501        }
502
503        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
504        enable_interrupts_noPoll();
505        /* paranoid */ verify( kernelTLS.preemption_state.enabled );
506
507        return preempted;
508}
509
510//=============================================================================================
511// Kernel Idle Sleep
512//=============================================================================================
513// Wake a thread from the front if there are any
514static void __wake_one(cluster * this) {
515        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
516        /* paranoid */ verify( ready_schedule_islocked() );
517
518        // Check if there is a sleeping processor
519        processor * p;
520        unsigned idle;
521        unsigned total;
522        [idle, total, p] = query(this->idles);
523
524        // If no one is sleeping, we are done
525        if( idle == 0 ) return;
526
527        // We found a processor, wake it up
528        post( p->idle );
529
530        #if !defined(__CFA_NO_STATISTICS__)
531                __tls_stats()->ready.sleep.wakes++;
532        #endif
533
534        /* paranoid */ verify( ready_schedule_islocked() );
535        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
536
537        return;
538}
539
540// Unconditionnaly wake a thread
541void __wake_proc(processor * this) {
542        __cfadbg_print_safe(runtime_core, "Kernel : waking Processor %p\n", this);
543
544        disable_interrupts();
545                /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
546                post( this->idle );
547        enable_interrupts( __cfaabi_dbg_ctx );
548}
549
550static void push  (__cluster_idles & this, processor & proc) {
551        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
552        lock( this );
553                this.idle++;
554                /* paranoid */ verify( this.idle <= this.total );
555
556                insert_first(this.list, proc);
557        unlock( this );
558        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
559}
560
561static void remove(__cluster_idles & this, processor & proc) {
562        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
563        lock( this );
564                this.idle--;
565                /* paranoid */ verify( this.idle >= 0 );
566
567                remove(proc);
568        unlock( this );
569        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
570}
571
572static [unsigned idle, unsigned total, * processor] query( & __cluster_idles this ) {
573        for() {
574                uint64_t l = __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST);
575                if( 1 == (l % 2) ) { Pause(); continue; }
576                unsigned idle    = this.idle;
577                unsigned total   = this.total;
578                processor * proc = &this.list`first;
579                // Compiler fence is unnecessary, but gcc-8 and older incorrectly reorder code without it
580                asm volatile("": : :"memory");
581                if(l != __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST)) { Pause(); continue; }
582                return [idle, total, proc];
583        }
584}
585
586//=============================================================================================
587// Unexpected Terminating logic
588//=============================================================================================
589static __spinlock_t kernel_abort_lock;
590static bool kernel_abort_called = false;
591
592void * kernel_abort(void) __attribute__ ((__nothrow__)) {
593        // abort cannot be recursively entered by the same or different processors because all signal handlers return when
594        // the globalAbort flag is true.
595        lock( kernel_abort_lock __cfaabi_dbg_ctx2 );
596
597        // first task to abort ?
598        if ( kernel_abort_called ) {                    // not first task to abort ?
599                unlock( kernel_abort_lock );
600
601                sigset_t mask;
602                sigemptyset( &mask );
603                sigaddset( &mask, SIGALRM );            // block SIGALRM signals
604                sigaddset( &mask, SIGUSR1 );            // block SIGALRM signals
605                sigsuspend( &mask );                            // block the processor to prevent further damage during abort
606                _exit( EXIT_FAILURE );                          // if processor unblocks before it is killed, terminate it
607        }
608        else {
609                kernel_abort_called = true;
610                unlock( kernel_abort_lock );
611        }
612
613        return kernelTLS.this_thread;
614}
615
616void kernel_abort_msg( void * kernel_data, char * abort_text, int abort_text_size ) {
617        $thread * thrd = ( $thread * ) kernel_data;
618
619        if(thrd) {
620                int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
621                __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
622
623                if ( &thrd->self_cor != thrd->curr_cor ) {
624                        len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
625                        __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
626                }
627                else {
628                        __cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
629                }
630        }
631        else {
632                int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
633                __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
634        }
635}
636
637int kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
638        return get_coroutine(kernelTLS.this_thread) == get_coroutine(mainThread) ? 4 : 2;
639}
640
641static __spinlock_t kernel_debug_lock;
642
643extern "C" {
644        void __cfaabi_bits_acquire() {
645                lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
646        }
647
648        void __cfaabi_bits_release() {
649                unlock( kernel_debug_lock );
650        }
651}
652
653//=============================================================================================
654// Kernel Utilities
655//=============================================================================================
656//-----------------------------------------------------------------------------
657// Locks
658void  ?{}( semaphore & this, int count = 1 ) {
659        (this.lock){};
660        this.count = count;
661        (this.waiting){};
662}
663void ^?{}(semaphore & this) {}
664
665bool P(semaphore & this) with( this ){
666        lock( lock __cfaabi_dbg_ctx2 );
667        count -= 1;
668        if ( count < 0 ) {
669                // queue current task
670                append( waiting, kernelTLS.this_thread );
671
672                // atomically release spin lock and block
673                unlock( lock );
674                park();
675                return true;
676        }
677        else {
678            unlock( lock );
679            return false;
680        }
681}
682
683bool V(semaphore & this) with( this ) {
684        $thread * thrd = 0p;
685        lock( lock __cfaabi_dbg_ctx2 );
686        count += 1;
687        if ( count <= 0 ) {
688                // remove task at head of waiting list
689                thrd = pop_head( waiting );
690        }
691
692        unlock( lock );
693
694        // make new owner
695        unpark( thrd );
696
697        return thrd != 0p;
698}
699
700bool V(semaphore & this, unsigned diff) with( this ) {
701        $thread * thrd = 0p;
702        lock( lock __cfaabi_dbg_ctx2 );
703        int release = max(-count, (int)diff);
704        count += diff;
705        for(release) {
706                unpark( pop_head( waiting ) );
707        }
708
709        unlock( lock );
710
711        return thrd != 0p;
712}
713
714//-----------------------------------------------------------------------------
715// Debug
716__cfaabi_dbg_debug_do(
717        extern "C" {
718                void __cfaabi_dbg_record_lock(__spinlock_t & this, const char prev_name[]) {
719                        this.prev_name = prev_name;
720                        this.prev_thrd = kernelTLS.this_thread;
721                }
722        }
723)
724
725//-----------------------------------------------------------------------------
726// Debug
727bool threading_enabled(void) __attribute__((const)) {
728        return true;
729}
730
731//-----------------------------------------------------------------------------
732// Statistics
733#if !defined(__CFA_NO_STATISTICS__)
734        void print_halts( processor & this ) {
735                this.print_halts = true;
736        }
737
738        void print_stats_now( cluster & this, int flags ) {
739                __print_stats( this.stats, this.print_stats, true, this.name, (void*)&this );
740        }
741#endif
742// Local Variables: //
743// mode: c //
744// tab-width: 4 //
745// End: //
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