source: libcfa/src/concurrency/kernel.cfa @ 0190480

arm-ehjacob/cs343-translationnew-ast-unique-expr
Last change on this file since 0190480 was 0190480, checked in by Peter A. Buhr <pabuhr@…>, 15 months ago

update for 32-bit ARM

  • Property mode set to 100644
File size: 22.6 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(struct __processor_id_t * id, 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        // Update global state
240        kernelTLS.this_thread = thrd_dst;
241
242        // set state of processor coroutine to inactive
243        verify(proc_cor->state == Active);
244        proc_cor->state = Blocked;
245
246        // Actually run the thread
247        RUNNING:  while(true) {
248                thrd_dst->preempted = __NO_PREEMPTION;
249                thrd_dst->state = Active;
250
251                __cfaabi_dbg_debug_do(
252                        thrd_dst->park_stale   = true;
253                        thrd_dst->unpark_stale = true;
254                )
255
256                /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
257                /* paranoid */ verify( kernelTLS.this_thread == thrd_dst );
258                /* 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
259                /* 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
260
261                // set context switch to the thread that the processor is executing
262                verify( thrd_dst->context.SP );
263                __cfactx_switch( &proc_cor->context, &thrd_dst->context );
264                // when __cfactx_switch returns we are back in the processor coroutine
265
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( kernelTLS.this_thread == thrd_dst );
269                /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
270
271
272                // We just finished running a thread, there are a few things that could have happened.
273                // 1 - Regular case : the thread has blocked and now one has scheduled it yet.
274                // 2 - Racy case    : the thread has blocked but someone has already tried to schedule it.
275                // 4 - Preempted
276                // In case 1, we may have won a race so we can't write to the state again.
277                // In case 2, we lost the race so we now own the thread.
278
279                if(unlikely(thrd_dst->preempted != __NO_PREEMPTION)) {
280                        // The thread was preempted, reschedule it and reset the flag
281                        __schedule_thread( (__processor_id_t*)this, thrd_dst );
282                        break RUNNING;
283                }
284
285                if(unlikely(thrd_dst->state == Halted)) {
286                        // The thread has halted, it should never be scheduled/run again
287                        // We may need to wake someone up here since
288                        unpark( this->destroyer __cfaabi_dbg_ctx2 );
289                        this->destroyer = 0p;
290                        break RUNNING;
291                }
292
293                /* paranoid */ verify( thrd_dst->state == Active );
294                thrd_dst->state = Blocked;
295
296                // set state of processor coroutine to active and the thread to inactive
297                int old_ticket = __atomic_fetch_sub(&thrd_dst->ticket, 1, __ATOMIC_SEQ_CST);
298                __cfaabi_dbg_debug_do( thrd_dst->park_result = old_ticket; )
299                switch(old_ticket) {
300                        case 1:
301                                // This is case 1, the regular case, nothing more is needed
302                                break RUNNING;
303                        case 2:
304                                // This is case 2, the racy case, someone tried to run this thread before it finished blocking
305                                // In this case, just run it again.
306                                continue RUNNING;
307                        default:
308                                // This makes no sense, something is wrong abort
309                                abort();
310                }
311        }
312
313        // Just before returning to the processor, set the processor coroutine to active
314        proc_cor->state = Active;
315        kernelTLS.this_thread = 0p;
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                verify( proc_cor->context.SP );
337                __cfactx_switch( &thrd_src->context, &proc_cor->context );
338                #if defined( __i386 ) || defined( __x86_64 )
339                        __x87_load;
340                #endif
341                *__volatile_errno() = local_errno;
342        }
343
344        #if !defined(__CFA_NO_STATISTICS__)
345                if(last_proc != kernelTLS.this_processor) {
346                        __tls_stats()->ready.threads.migration++;
347                }
348        #endif
349
350        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
351        /* 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 );
352        /* 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 );
353}
354
355//-----------------------------------------------------------------------------
356// Scheduler routines
357// KERNEL ONLY
358void __schedule_thread( struct __processor_id_t * id, $thread * thrd ) {
359        /* paranoid */ verify( thrd );
360        /* paranoid */ verify( thrd->state != Halted );
361        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
362        /* paranoid */ #if defined( __CFA_WITH_VERIFY__ )
363        /* paranoid */  if( thrd->state == Blocked || thrd->state == Start ) assertf( thrd->preempted == __NO_PREEMPTION,
364                                        "Error inactive thread marked as preempted, state %d, preemption %d\n", thrd->state, thrd->preempted );
365        /* paranoid */  if( thrd->preempted != __NO_PREEMPTION ) assertf(thrd->state == Active,
366                                        "Error preempted thread marked as not currently running, state %d, preemption %d\n", thrd->state, thrd->preempted );
367        /* paranoid */ #endif
368        /* paranoid */ verifyf( thrd->link.next == 0p, "Expected null got %p", thrd->link.next );
369
370        if (thrd->preempted == __NO_PREEMPTION) thrd->state = Ready;
371
372        ready_schedule_lock  ( id );
373                push( thrd->curr_cluster, thrd );
374                __wake_one(id, thrd->curr_cluster);
375        ready_schedule_unlock( id );
376
377        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
378}
379
380// KERNEL ONLY
381static inline $thread * __next_thread(cluster * this) with( *this ) {
382        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
383
384        ready_schedule_lock  ( (__processor_id_t*)kernelTLS.this_processor );
385                $thread * thrd = pop( this );
386        ready_schedule_unlock( (__processor_id_t*)kernelTLS.this_processor );
387
388        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
389        return thrd;
390}
391
392// KERNEL ONLY
393static inline $thread * __next_thread_slow(cluster * this) with( *this ) {
394        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
395
396        ready_schedule_lock  ( (__processor_id_t*)kernelTLS.this_processor );
397                $thread * thrd = pop_slow( this );
398        ready_schedule_unlock( (__processor_id_t*)kernelTLS.this_processor );
399
400        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
401        return thrd;
402}
403
404// KERNEL ONLY unpark with out disabling interrupts
405void __unpark(  struct __processor_id_t * id, $thread * thrd __cfaabi_dbg_ctx_param2 ) {
406        // record activity
407        __cfaabi_dbg_record_thrd( *thrd, false, caller );
408
409        int old_ticket = __atomic_fetch_add(&thrd->ticket, 1, __ATOMIC_SEQ_CST);
410        __cfaabi_dbg_debug_do( thrd->unpark_result = old_ticket; thrd->unpark_state = thrd->state; )
411        switch(old_ticket) {
412                case 1:
413                        // Wake won the race, the thread will reschedule/rerun itself
414                        break;
415                case 0:
416                        /* paranoid */ verify( ! thrd->preempted != __NO_PREEMPTION );
417                        /* paranoid */ verify( thrd->state == Blocked );
418
419                        // Wake lost the race,
420                        __schedule_thread( id, thrd );
421                        break;
422                default:
423                        // This makes no sense, something is wrong abort
424                        abort();
425        }
426}
427
428void unpark( $thread * thrd __cfaabi_dbg_ctx_param2 ) {
429        if( !thrd ) return;
430
431        disable_interrupts();
432        __unpark( (__processor_id_t*)kernelTLS.this_processor, thrd __cfaabi_dbg_ctx_fwd2 );
433        enable_interrupts( __cfaabi_dbg_ctx );
434}
435
436void park( __cfaabi_dbg_ctx_param ) {
437        /* paranoid */ verify( kernelTLS.preemption_state.enabled );
438        disable_interrupts();
439        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
440        /* paranoid */ verify( kernelTLS.this_thread->preempted == __NO_PREEMPTION );
441
442        // record activity
443        __cfaabi_dbg_record_thrd( *kernelTLS.this_thread, true, caller );
444
445        returnToKernel();
446
447        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
448        enable_interrupts( __cfaabi_dbg_ctx );
449        /* paranoid */ verify( kernelTLS.preemption_state.enabled );
450
451}
452
453// KERNEL ONLY
454void __leave_thread() {
455        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
456        returnToKernel();
457        abort();
458}
459
460// KERNEL ONLY
461bool force_yield( __Preemption_Reason reason ) {
462        /* paranoid */ verify( kernelTLS.preemption_state.enabled );
463        disable_interrupts();
464        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
465
466        $thread * thrd = kernelTLS.this_thread;
467        /* paranoid */ verify(thrd->state == Active);
468
469        // SKULLDUGGERY: It is possible that we are preempting this thread just before
470        // it was going to park itself. If that is the case and it is already using the
471        // intrusive fields then we can't use them to preempt the thread
472        // If that is the case, abandon the preemption.
473        bool preempted = false;
474        if(thrd->link.next == 0p) {
475                preempted = true;
476                thrd->preempted = reason;
477                returnToKernel();
478        }
479
480        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
481        enable_interrupts_noPoll();
482        /* paranoid */ verify( kernelTLS.preemption_state.enabled );
483
484        return preempted;
485}
486
487//=============================================================================================
488// Kernel Idle Sleep
489//=============================================================================================
490// Wake a thread from the front if there are any
491static void __wake_one(struct __processor_id_t * id, cluster * this) {
492        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
493        /* paranoid */ verify( ready_schedule_islocked( id ) );
494
495        // Check if there is a sleeping processor
496        processor * p;
497        unsigned idle;
498        unsigned total;
499        [idle, total, p] = query(this->idles);
500
501        // If no one is sleeping, we are done
502        if( idle == 0 ) return;
503
504        // We found a processor, wake it up
505        post( p->idle );
506
507        #if !defined(__CFA_NO_STATISTICS__)
508                __tls_stats()->ready.sleep.wakes++;
509        #endif
510
511        /* paranoid */ verify( ready_schedule_islocked( id ) );
512        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
513
514        return;
515}
516
517// Unconditionnaly wake a thread
518void __wake_proc(processor * this) {
519        __cfadbg_print_safe(runtime_core, "Kernel : waking Processor %p\n", this);
520
521        disable_interrupts();
522                /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
523                bool ret = post( this->idle );
524        enable_interrupts( __cfaabi_dbg_ctx );
525}
526
527static void push  (__cluster_idles & this, processor & proc) {
528        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
529        lock( this );
530                this.idle++;
531                /* paranoid */ verify( this.idle <= this.total );
532
533                insert_first(this.list, proc);
534        unlock( this );
535        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
536}
537
538static void remove(__cluster_idles & this, processor & proc) {
539        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
540        lock( this );
541                this.idle--;
542                /* paranoid */ verify( this.idle >= 0 );
543
544                remove(proc);
545        unlock( this );
546        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
547}
548
549static [unsigned idle, unsigned total, * processor] query( & __cluster_idles this ) {
550        for() {
551                uint64_t l = __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST);
552                if( 1 == (l % 2) ) { Pause(); continue; }
553                unsigned idle    = this.idle;
554                unsigned total   = this.total;
555                processor * proc = &this.list`first;
556                // Compiler fence is unnecessary, but gcc-8 and older incorrectly reorder code without it
557                asm volatile("": : :"memory");
558                if(l != __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST)) { Pause(); continue; }
559                return [idle, total, proc];
560        }
561}
562
563//=============================================================================================
564// Unexpected Terminating logic
565//=============================================================================================
566static __spinlock_t kernel_abort_lock;
567static bool kernel_abort_called = false;
568
569void * kernel_abort(void) __attribute__ ((__nothrow__)) {
570        // abort cannot be recursively entered by the same or different processors because all signal handlers return when
571        // the globalAbort flag is true.
572        lock( kernel_abort_lock __cfaabi_dbg_ctx2 );
573
574        // first task to abort ?
575        if ( kernel_abort_called ) {                    // not first task to abort ?
576                unlock( kernel_abort_lock );
577
578                sigset_t mask;
579                sigemptyset( &mask );
580                sigaddset( &mask, SIGALRM );            // block SIGALRM signals
581                sigaddset( &mask, SIGUSR1 );            // block SIGALRM signals
582                sigsuspend( &mask );                            // block the processor to prevent further damage during abort
583                _exit( EXIT_FAILURE );                          // if processor unblocks before it is killed, terminate it
584        }
585        else {
586                kernel_abort_called = true;
587                unlock( kernel_abort_lock );
588        }
589
590        return kernelTLS.this_thread;
591}
592
593void kernel_abort_msg( void * kernel_data, char * abort_text, int abort_text_size ) {
594        $thread * thrd = ( $thread * ) kernel_data;
595
596        if(thrd) {
597                int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
598                __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
599
600                if ( &thrd->self_cor != thrd->curr_cor ) {
601                        len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
602                        __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
603                }
604                else {
605                        __cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
606                }
607        }
608        else {
609                int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
610                __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
611        }
612}
613
614int kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
615        return get_coroutine(kernelTLS.this_thread) == get_coroutine(mainThread) ? 4 : 2;
616}
617
618static __spinlock_t kernel_debug_lock;
619
620extern "C" {
621        void __cfaabi_bits_acquire() {
622                lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
623        }
624
625        void __cfaabi_bits_release() {
626                unlock( kernel_debug_lock );
627        }
628}
629
630//=============================================================================================
631// Kernel Utilities
632//=============================================================================================
633//-----------------------------------------------------------------------------
634// Locks
635void  ?{}( semaphore & this, int count = 1 ) {
636        (this.lock){};
637        this.count = count;
638        (this.waiting){};
639}
640void ^?{}(semaphore & this) {}
641
642bool P(semaphore & this) with( this ){
643        lock( lock __cfaabi_dbg_ctx2 );
644        count -= 1;
645        if ( count < 0 ) {
646                // queue current task
647                append( waiting, kernelTLS.this_thread );
648
649                // atomically release spin lock and block
650                unlock( lock );
651                park( __cfaabi_dbg_ctx );
652                return true;
653        }
654        else {
655            unlock( lock );
656            return false;
657        }
658}
659
660bool V(semaphore & this) with( this ) {
661        $thread * thrd = 0p;
662        lock( lock __cfaabi_dbg_ctx2 );
663        count += 1;
664        if ( count <= 0 ) {
665                // remove task at head of waiting list
666                thrd = pop_head( waiting );
667        }
668
669        unlock( lock );
670
671        // make new owner
672        unpark( thrd __cfaabi_dbg_ctx2 );
673
674        return thrd != 0p;
675}
676
677bool V(semaphore & this, unsigned diff) with( this ) {
678        $thread * thrd = 0p;
679        lock( lock __cfaabi_dbg_ctx2 );
680        int release = max(-count, (int)diff);
681        count += diff;
682        for(release) {
683                unpark( pop_head( waiting ) __cfaabi_dbg_ctx2 );
684        }
685
686        unlock( lock );
687
688        return thrd != 0p;
689}
690
691//-----------------------------------------------------------------------------
692// Debug
693__cfaabi_dbg_debug_do(
694        extern "C" {
695                void __cfaabi_dbg_record_lock(__spinlock_t & this, const char prev_name[]) {
696                        this.prev_name = prev_name;
697                        this.prev_thrd = kernelTLS.this_thread;
698                }
699
700                void __cfaabi_dbg_record_thrd($thread & this, bool park, const char prev_name[]) {
701                        if(park) {
702                                this.park_caller   = prev_name;
703                                this.park_stale    = false;
704                        }
705                        else {
706                                this.unpark_caller = prev_name;
707                                this.unpark_stale  = false;
708                        }
709                }
710        }
711)
712
713//-----------------------------------------------------------------------------
714// Debug
715bool threading_enabled(void) __attribute__((const)) {
716        return true;
717}
718
719//-----------------------------------------------------------------------------
720// Statistics
721#if !defined(__CFA_NO_STATISTICS__)
722        void print_halts( processor & this ) {
723                this.print_halts = true;
724        }
725#endif
726// Local Variables: //
727// mode: c //
728// tab-width: 4 //
729// End: //
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