source: libcfa/src/concurrency/kernel.cfa @ 58d64a4

arm-ehjacob/cs343-translationnew-ast-unique-expr
Last change on this file since 58d64a4 was 58d64a4, checked in by Thierry Delisle <tdelisle@…>, 14 months ago

processor_id_t now have a bool to state if it is a full processor.
kernelTLS.this_thread now has much tighter lifetime.
Remove warning in kernel.cfa

  • 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        // 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                __cfaabi_dbg_debug_do(
249                        thrd_dst->park_stale   = true;
250                        thrd_dst->unpark_stale = true;
251                )
252                // Update global state
253                kernelTLS.this_thread = thrd_dst;
254
255                /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
256                /* paranoid */ verify( kernelTLS.this_thread == thrd_dst );
257                /* 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
258                /* 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
259
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                // Reset global state
272                kernelTLS.this_thread = 0p;
273
274                // We just finished running a thread, there are a few things that could have happened.
275                // 1 - Regular case : the thread has blocked and now one has scheduled it yet.
276                // 2 - Racy case    : the thread has blocked but someone has already tried to schedule it.
277                // 4 - Preempted
278                // In case 1, we may have won a race so we can't write to the state again.
279                // In case 2, we lost the race so we now own the thread.
280
281                if(unlikely(thrd_dst->preempted != __NO_PREEMPTION)) {
282                        // The thread was preempted, reschedule it and reset the flag
283                        __schedule_thread( (__processor_id_t*)this, thrd_dst );
284                        break RUNNING;
285                }
286
287                if(unlikely(thrd_dst->state == Halted)) {
288                        // The thread has halted, it should never be scheduled/run again
289                        // We may need to wake someone up here since
290                        unpark( this->destroyer __cfaabi_dbg_ctx2 );
291                        this->destroyer = 0p;
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                __cfaabi_dbg_debug_do( thrd_dst->park_result = old_ticket; )
301                switch(old_ticket) {
302                        case 1:
303                                // This is case 1, the regular case, nothing more is needed
304                                break RUNNING;
305                        case 2:
306                                // This is case 2, the racy case, someone tried to run this thread before it finished blocking
307                                // In this case, just run it again.
308                                continue RUNNING;
309                        default:
310                                // This makes no sense, something is wrong abort
311                                abort();
312                }
313        }
314
315        // Just before returning to the processor, set the processor coroutine to active
316        proc_cor->state = Active;
317
318        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
319}
320
321// KERNEL_ONLY
322void returnToKernel() {
323        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
324        $coroutine * proc_cor = get_coroutine(kernelTLS.this_processor->runner);
325        $thread * thrd_src = kernelTLS.this_thread;
326
327        #if !defined(__CFA_NO_STATISTICS__)
328                struct processor * last_proc = kernelTLS.this_processor;
329        #endif
330
331        // Run the thread on this processor
332        {
333                int local_errno = *__volatile_errno();
334                #if defined( __i386 ) || defined( __x86_64 )
335                        __x87_store;
336                #endif
337                verify( proc_cor->context.SP );
338                __cfactx_switch( &thrd_src->context, &proc_cor->context );
339                #if defined( __i386 ) || defined( __x86_64 )
340                        __x87_load;
341                #endif
342                *__volatile_errno() = local_errno;
343        }
344
345        #if !defined(__CFA_NO_STATISTICS__)
346                if(last_proc != kernelTLS.this_processor) {
347                        __tls_stats()->ready.threads.migration++;
348                }
349        #endif
350
351        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
352        /* 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 );
353        /* 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 );
354}
355
356//-----------------------------------------------------------------------------
357// Scheduler routines
358// KERNEL ONLY
359void __schedule_thread( struct __processor_id_t * id, $thread * thrd ) {
360        /* paranoid */ verify( thrd );
361        /* paranoid */ verify( thrd->state != Halted );
362        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
363        /* paranoid */ #if defined( __CFA_WITH_VERIFY__ )
364        /* paranoid */  if( thrd->state == Blocked || thrd->state == Start ) assertf( thrd->preempted == __NO_PREEMPTION,
365                                        "Error inactive thread marked as preempted, state %d, preemption %d\n", thrd->state, thrd->preempted );
366        /* paranoid */  if( thrd->preempted != __NO_PREEMPTION ) assertf(thrd->state == Active,
367                                        "Error preempted thread marked as not currently running, state %d, preemption %d\n", thrd->state, thrd->preempted );
368        /* paranoid */ #endif
369        /* paranoid */ verifyf( thrd->link.next == 0p, "Expected null got %p", thrd->link.next );
370
371        if (thrd->preempted == __NO_PREEMPTION) thrd->state = Ready;
372
373        ready_schedule_lock  ( id );
374                push( thrd->curr_cluster, thrd );
375                __wake_one(id, thrd->curr_cluster);
376        ready_schedule_unlock( id );
377
378        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
379}
380
381// KERNEL ONLY
382static inline $thread * __next_thread(cluster * this) with( *this ) {
383        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
384
385        ready_schedule_lock  ( (__processor_id_t*)kernelTLS.this_processor );
386                $thread * thrd = pop( this );
387        ready_schedule_unlock( (__processor_id_t*)kernelTLS.this_processor );
388
389        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
390        return thrd;
391}
392
393// KERNEL ONLY
394static inline $thread * __next_thread_slow(cluster * this) with( *this ) {
395        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
396
397        ready_schedule_lock  ( (__processor_id_t*)kernelTLS.this_processor );
398                $thread * thrd = pop_slow( this );
399        ready_schedule_unlock( (__processor_id_t*)kernelTLS.this_processor );
400
401        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
402        return thrd;
403}
404
405// KERNEL ONLY unpark with out disabling interrupts
406void __unpark(  struct __processor_id_t * id, $thread * thrd __cfaabi_dbg_ctx_param2 ) {
407        // record activity
408        __cfaabi_dbg_record_thrd( *thrd, false, caller );
409
410        int old_ticket = __atomic_fetch_add(&thrd->ticket, 1, __ATOMIC_SEQ_CST);
411        __cfaabi_dbg_debug_do( thrd->unpark_result = old_ticket; thrd->unpark_state = thrd->state; )
412        switch(old_ticket) {
413                case 1:
414                        // Wake won the race, the thread will reschedule/rerun itself
415                        break;
416                case 0:
417                        /* paranoid */ verify( ! thrd->preempted != __NO_PREEMPTION );
418                        /* paranoid */ verify( thrd->state == Blocked );
419
420                        // Wake lost the race,
421                        __schedule_thread( id, thrd );
422                        break;
423                default:
424                        // This makes no sense, something is wrong abort
425                        abort();
426        }
427}
428
429void unpark( $thread * thrd __cfaabi_dbg_ctx_param2 ) {
430        if( !thrd ) return;
431
432        disable_interrupts();
433        __unpark( (__processor_id_t*)kernelTLS.this_processor, thrd __cfaabi_dbg_ctx_fwd2 );
434        enable_interrupts( __cfaabi_dbg_ctx );
435}
436
437void park( __cfaabi_dbg_ctx_param ) {
438        /* paranoid */ verify( kernelTLS.preemption_state.enabled );
439        disable_interrupts();
440        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
441        /* paranoid */ verify( kernelTLS.this_thread->preempted == __NO_PREEMPTION );
442
443        // record activity
444        __cfaabi_dbg_record_thrd( *kernelTLS.this_thread, true, caller );
445
446        returnToKernel();
447
448        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
449        enable_interrupts( __cfaabi_dbg_ctx );
450        /* paranoid */ verify( kernelTLS.preemption_state.enabled );
451
452}
453
454// KERNEL ONLY
455void __leave_thread() {
456        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
457        returnToKernel();
458        abort();
459}
460
461// KERNEL ONLY
462bool force_yield( __Preemption_Reason reason ) {
463        /* paranoid */ verify( kernelTLS.preemption_state.enabled );
464        disable_interrupts();
465        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
466
467        $thread * thrd = kernelTLS.this_thread;
468        /* paranoid */ verify(thrd->state == Active);
469
470        // SKULLDUGGERY: It is possible that we are preempting this thread just before
471        // it was going to park itself. If that is the case and it is already using the
472        // intrusive fields then we can't use them to preempt the thread
473        // If that is the case, abandon the preemption.
474        bool preempted = false;
475        if(thrd->link.next == 0p) {
476                preempted = true;
477                thrd->preempted = reason;
478                returnToKernel();
479        }
480
481        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
482        enable_interrupts_noPoll();
483        /* paranoid */ verify( kernelTLS.preemption_state.enabled );
484
485        return preempted;
486}
487
488//=============================================================================================
489// Kernel Idle Sleep
490//=============================================================================================
491// Wake a thread from the front if there are any
492static void __wake_one(struct __processor_id_t * id, cluster * this) {
493        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
494        /* paranoid */ verify( ready_schedule_islocked( id ) );
495
496        // Check if there is a sleeping processor
497        processor * p;
498        unsigned idle;
499        unsigned total;
500        [idle, total, p] = query(this->idles);
501
502        // If no one is sleeping, we are done
503        if( idle == 0 ) return;
504
505        // We found a processor, wake it up
506        post( p->idle );
507
508        #if !defined(__CFA_NO_STATISTICS__)
509                __tls_stats()->ready.sleep.wakes++;
510        #endif
511
512        /* paranoid */ verify( ready_schedule_islocked( id ) );
513        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
514
515        return;
516}
517
518// Unconditionnaly wake a thread
519void __wake_proc(processor * this) {
520        __cfadbg_print_safe(runtime_core, "Kernel : waking Processor %p\n", this);
521
522        disable_interrupts();
523                /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
524                post( this->idle );
525        enable_interrupts( __cfaabi_dbg_ctx );
526}
527
528static void push  (__cluster_idles & this, processor & proc) {
529        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
530        lock( this );
531                this.idle++;
532                /* paranoid */ verify( this.idle <= this.total );
533
534                insert_first(this.list, proc);
535        unlock( this );
536        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
537}
538
539static void remove(__cluster_idles & this, processor & proc) {
540        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
541        lock( this );
542                this.idle--;
543                /* paranoid */ verify( this.idle >= 0 );
544
545                remove(proc);
546        unlock( this );
547        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
548}
549
550static [unsigned idle, unsigned total, * processor] query( & __cluster_idles this ) {
551        for() {
552                uint64_t l = __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST);
553                if( 1 == (l % 2) ) { Pause(); continue; }
554                unsigned idle    = this.idle;
555                unsigned total   = this.total;
556                processor * proc = &this.list`first;
557                // Compiler fence is unnecessary, but gcc-8 and older incorrectly reorder code without it
558                asm volatile("": : :"memory");
559                if(l != __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST)) { Pause(); continue; }
560                return [idle, total, proc];
561        }
562}
563
564//=============================================================================================
565// Unexpected Terminating logic
566//=============================================================================================
567static __spinlock_t kernel_abort_lock;
568static bool kernel_abort_called = false;
569
570void * kernel_abort(void) __attribute__ ((__nothrow__)) {
571        // abort cannot be recursively entered by the same or different processors because all signal handlers return when
572        // the globalAbort flag is true.
573        lock( kernel_abort_lock __cfaabi_dbg_ctx2 );
574
575        // first task to abort ?
576        if ( kernel_abort_called ) {                    // not first task to abort ?
577                unlock( kernel_abort_lock );
578
579                sigset_t mask;
580                sigemptyset( &mask );
581                sigaddset( &mask, SIGALRM );            // block SIGALRM signals
582                sigaddset( &mask, SIGUSR1 );            // block SIGALRM signals
583                sigsuspend( &mask );                            // block the processor to prevent further damage during abort
584                _exit( EXIT_FAILURE );                          // if processor unblocks before it is killed, terminate it
585        }
586        else {
587                kernel_abort_called = true;
588                unlock( kernel_abort_lock );
589        }
590
591        return kernelTLS.this_thread;
592}
593
594void kernel_abort_msg( void * kernel_data, char * abort_text, int abort_text_size ) {
595        $thread * thrd = ( $thread * ) kernel_data;
596
597        if(thrd) {
598                int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
599                __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
600
601                if ( &thrd->self_cor != thrd->curr_cor ) {
602                        len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
603                        __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
604                }
605                else {
606                        __cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
607                }
608        }
609        else {
610                int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
611                __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
612        }
613}
614
615int kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
616        return get_coroutine(kernelTLS.this_thread) == get_coroutine(mainThread) ? 4 : 2;
617}
618
619static __spinlock_t kernel_debug_lock;
620
621extern "C" {
622        void __cfaabi_bits_acquire() {
623                lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
624        }
625
626        void __cfaabi_bits_release() {
627                unlock( kernel_debug_lock );
628        }
629}
630
631//=============================================================================================
632// Kernel Utilities
633//=============================================================================================
634//-----------------------------------------------------------------------------
635// Locks
636void  ?{}( semaphore & this, int count = 1 ) {
637        (this.lock){};
638        this.count = count;
639        (this.waiting){};
640}
641void ^?{}(semaphore & this) {}
642
643bool P(semaphore & this) with( this ){
644        lock( lock __cfaabi_dbg_ctx2 );
645        count -= 1;
646        if ( count < 0 ) {
647                // queue current task
648                append( waiting, kernelTLS.this_thread );
649
650                // atomically release spin lock and block
651                unlock( lock );
652                park( __cfaabi_dbg_ctx );
653                return true;
654        }
655        else {
656            unlock( lock );
657            return false;
658        }
659}
660
661bool V(semaphore & this) with( this ) {
662        $thread * thrd = 0p;
663        lock( lock __cfaabi_dbg_ctx2 );
664        count += 1;
665        if ( count <= 0 ) {
666                // remove task at head of waiting list
667                thrd = pop_head( waiting );
668        }
669
670        unlock( lock );
671
672        // make new owner
673        unpark( thrd __cfaabi_dbg_ctx2 );
674
675        return thrd != 0p;
676}
677
678bool V(semaphore & this, unsigned diff) with( this ) {
679        $thread * thrd = 0p;
680        lock( lock __cfaabi_dbg_ctx2 );
681        int release = max(-count, (int)diff);
682        count += diff;
683        for(release) {
684                unpark( pop_head( waiting ) __cfaabi_dbg_ctx2 );
685        }
686
687        unlock( lock );
688
689        return thrd != 0p;
690}
691
692//-----------------------------------------------------------------------------
693// Debug
694__cfaabi_dbg_debug_do(
695        extern "C" {
696                void __cfaabi_dbg_record_lock(__spinlock_t & this, const char prev_name[]) {
697                        this.prev_name = prev_name;
698                        this.prev_thrd = kernelTLS.this_thread;
699                }
700
701                void __cfaabi_dbg_record_thrd($thread & this, bool park, const char prev_name[]) {
702                        if(park) {
703                                this.park_caller   = prev_name;
704                                this.park_stale    = false;
705                        }
706                        else {
707                                this.unpark_caller = prev_name;
708                                this.unpark_stale  = false;
709                        }
710                }
711        }
712)
713
714//-----------------------------------------------------------------------------
715// Debug
716bool threading_enabled(void) __attribute__((const)) {
717        return true;
718}
719
720//-----------------------------------------------------------------------------
721// Statistics
722#if !defined(__CFA_NO_STATISTICS__)
723        void print_halts( processor & this ) {
724                this.print_halts = true;
725        }
726#endif
727// Local Variables: //
728// mode: c //
729// tab-width: 4 //
730// End: //
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