source: libcfa/src/concurrency/kernel.cfa@ 305cd5c

ADT arm-eh ast-experimental enum forall-pointer-decay jacob/cs343-translation new-ast-unique-expr pthread-emulation qualifiedEnum
Last change on this file since 305cd5c was 0190480, checked in by Peter A. Buhr <pabuhr@…>, 5 years 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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