source: libcfa/src/concurrency/kernel.cfa@ 8e9d567

ADT arm-eh ast-experimental enum forall-pointer-decay jacob/cs343-translation new-ast-unique-expr pthread-emulation qualifiedEnum stuck-waitfor-destruct
Last change on this file since 8e9d567 was f2384c9a, checked in by Thierry Delisle <tdelisle@…>, 6 years ago

Added forward/reverse rng for later use in the ready queue
  • Property mode set to 100644
File size: 22.2 KB
Line 
1//
2// Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo
3//
4// The contents of this file are covered under the licence agreement in the
5// file "LICENCE" distributed with Cforall.
6//
7// kernel.c --
8//
9// Author : Thierry Delisle
10// Created On : Tue Jan 17 12:27:26 2017
11// Last Modified By : Peter A. Buhr
12// Last Modified On : Thu Jul 9 06:22:54 2020
13// Update Count : 66
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
77#elif defined( __ARM_ARCH )
78#else
79 #error unknown hardware architecture
80#endif
81
82extern $thread * mainThread;
83extern processor * mainProcessor;
84
85//-----------------------------------------------------------------------------
86// Kernel Scheduling logic
87static $thread * __next_thread(cluster * this);
88static $thread * __next_thread_slow(cluster * this);
89static void __run_thread(processor * this, $thread * dst);
90static void __wake_one(struct __processor_id_t * id, cluster * cltr);
91
92static void push (__cluster_idles & idles, processor & proc);
93static void remove(__cluster_idles & idles, processor & proc);
94static [unsigned idle, unsigned total, * processor] query( & __cluster_idles idles );
95
96
97//=============================================================================================
98// Kernel Scheduling logic
99//=============================================================================================
100//Main of the processor contexts
101void main(processorCtx_t & runner) {
102 // Because of a bug, we couldn't initialized the seed on construction
103 // Do it here
104 kernelTLS.rand_seed ^= rdtscl();
105 kernelTLS.ready_rng.fwd_seed = 25214903917_l64u * (rdtscl() ^ (uintptr_t)&runner);
106 __tls_rand_advance_bck();
107
108 processor * this = runner.proc;
109 verify(this);
110
111 __cfadbg_print_safe(runtime_core, "Kernel : core %p starting\n", this);
112 #if !defined(__CFA_NO_STATISTICS__)
113 if( this->print_halts ) {
114 __cfaabi_bits_print_safe( STDOUT_FILENO, "Processor : %d - %s (%p)\n", this->id, this->name, (void*)this);
115 }
116 #endif
117
118 {
119 // Setup preemption data
120 preemption_scope scope = { this };
121
122 __cfadbg_print_safe(runtime_core, "Kernel : core %p started\n", this);
123
124 $thread * readyThread = 0p;
125 MAIN_LOOP:
126 for() {
127 // Try to get the next thread
128 readyThread = __next_thread( this->cltr );
129
130 if( !readyThread ) {
131 readyThread = __next_thread_slow( this->cltr );
132 }
133
134 HALT:
135 if( !readyThread ) {
136 // Don't block if we are done
137 if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
138
139 #if !defined(__CFA_NO_STATISTICS__)
140 __tls_stats()->ready.sleep.halts++;
141 #endif
142
143 // Push self to idle stack
144 push(this->cltr->idles, * this);
145
146 // Confirm the ready-queue is empty
147 readyThread = __next_thread_slow( this->cltr );
148 if( readyThread ) {
149 // A thread was found, cancel the halt
150 remove(this->cltr->idles, * this);
151
152 #if !defined(__CFA_NO_STATISTICS__)
153 __tls_stats()->ready.sleep.cancels++;
154 #endif
155
156 // continue the mai loop
157 break HALT;
158 }
159
160 #if !defined(__CFA_NO_STATISTICS__)
161 if(this->print_halts) {
162 __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 0\n", this->id, rdtscl());
163 }
164 #endif
165
166 wait( this->idle );
167
168 #if !defined(__CFA_NO_STATISTICS__)
169 if(this->print_halts) {
170 __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 1\n", this->id, rdtscl());
171 }
172 #endif
173
174 // We were woken up, remove self from idle
175 remove(this->cltr->idles, * this);
176
177 // DON'T just proceed, start looking again
178 continue MAIN_LOOP;
179 }
180
181 /* paranoid */ verify( readyThread );
182
183 // We found a thread run it
184 __run_thread(this, readyThread);
185
186 // Are we done?
187 if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
188 }
189
190 __cfadbg_print_safe(runtime_core, "Kernel : core %p stopping\n", this);
191 }
192
193 V( this->terminated );
194
195 if(this == mainProcessor) {
196 // HACK : the coroutine context switch expects this_thread to be set
197 // and it make sense for it to be set in all other cases except here
198 // fake it
199 kernelTLS.this_thread = mainThread;
200 }
201
202 __cfadbg_print_safe(runtime_core, "Kernel : core %p terminated\n", this);
203}
204
205static int * __volatile_errno() __attribute__((noinline));
206static int * __volatile_errno() { asm(""); return &errno; }
207
208// KERNEL ONLY
209// runThread runs a thread by context switching
210// from the processor coroutine to the target thread
211static void __run_thread(processor * this, $thread * thrd_dst) {
212 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
213 /* paranoid */ verifyf( thrd_dst->state == Ready || thrd_dst->preempted != __NO_PREEMPTION, "state : %d, preempted %d\n", thrd_dst->state, thrd_dst->preempted);
214 /* paranoid */ verifyf( thrd_dst->link.next == 0p, "Expected null got %p", thrd_dst->link.next );
215 __builtin_prefetch( thrd_dst->context.SP );
216
217 $coroutine * proc_cor = get_coroutine(this->runner);
218
219 // Update global state
220 kernelTLS.this_thread = thrd_dst;
221
222 // set state of processor coroutine to inactive
223 verify(proc_cor->state == Active);
224 proc_cor->state = Blocked;
225
226 // Actually run the thread
227 RUNNING: while(true) {
228 thrd_dst->preempted = __NO_PREEMPTION;
229 thrd_dst->state = Active;
230
231 __cfaabi_dbg_debug_do(
232 thrd_dst->park_stale = true;
233 thrd_dst->unpark_stale = true;
234 )
235
236 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
237 /* paranoid */ verify( kernelTLS.this_thread == thrd_dst );
238 /* 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
239 /* 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
240
241 // set context switch to the thread that the processor is executing
242 verify( thrd_dst->context.SP );
243 __cfactx_switch( &proc_cor->context, &thrd_dst->context );
244 // when __cfactx_switch returns we are back in the processor coroutine
245
246 /* 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 );
247 /* 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 );
248 /* paranoid */ verify( kernelTLS.this_thread == thrd_dst );
249 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
250
251
252 // We just finished running a thread, there are a few things that could have happened.
253 // 1 - Regular case : the thread has blocked and now one has scheduled it yet.
254 // 2 - Racy case : the thread has blocked but someone has already tried to schedule it.
255 // 4 - Preempted
256 // In case 1, we may have won a race so we can't write to the state again.
257 // In case 2, we lost the race so we now own the thread.
258
259 if(unlikely(thrd_dst->preempted != __NO_PREEMPTION)) {
260 // The thread was preempted, reschedule it and reset the flag
261 __schedule_thread( (__processor_id_t*)this, thrd_dst );
262 break RUNNING;
263 }
264
265 if(unlikely(thrd_dst->state == Halted)) {
266 // The thread has halted, it should never be scheduled/run again
267 // We may need to wake someone up here since
268 unpark( this->destroyer __cfaabi_dbg_ctx2 );
269 this->destroyer = 0p;
270 break RUNNING;
271 }
272
273 /* paranoid */ verify( thrd_dst->state == Active );
274 thrd_dst->state = Blocked;
275
276 // set state of processor coroutine to active and the thread to inactive
277 int old_ticket = __atomic_fetch_sub(&thrd_dst->ticket, 1, __ATOMIC_SEQ_CST);
278 __cfaabi_dbg_debug_do( thrd_dst->park_result = old_ticket; )
279 switch(old_ticket) {
280 case 1:
281 // This is case 1, the regular case, nothing more is needed
282 break RUNNING;
283 case 2:
284 // This is case 2, the racy case, someone tried to run this thread before it finished blocking
285 // In this case, just run it again.
286 continue RUNNING;
287 default:
288 // This makes no sense, something is wrong abort
289 abort();
290 }
291 }
292
293 // Just before returning to the processor, set the processor coroutine to active
294 proc_cor->state = Active;
295 kernelTLS.this_thread = 0p;
296
297 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
298}
299
300// KERNEL_ONLY
301void returnToKernel() {
302 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
303 $coroutine * proc_cor = get_coroutine(kernelTLS.this_processor->runner);
304 $thread * thrd_src = kernelTLS.this_thread;
305
306 #if !defined(__CFA_NO_STATISTICS__)
307 struct processor * last_proc = kernelTLS.this_processor;
308 #endif
309
310 // Run the thread on this processor
311 {
312 int local_errno = *__volatile_errno();
313 #if defined( __i386 ) || defined( __x86_64 )
314 __x87_store;
315 #endif
316 verify( proc_cor->context.SP );
317 __cfactx_switch( &thrd_src->context, &proc_cor->context );
318 #if defined( __i386 ) || defined( __x86_64 )
319 __x87_load;
320 #endif
321 *__volatile_errno() = local_errno;
322 }
323
324 #if !defined(__CFA_NO_STATISTICS__)
325 if(last_proc != kernelTLS.this_processor) {
326 __tls_stats()->ready.threads.migration++;
327 }
328 #endif
329
330 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
331 /* 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 );
332 /* 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 );
333}
334
335//-----------------------------------------------------------------------------
336// Scheduler routines
337// KERNEL ONLY
338void __schedule_thread( struct __processor_id_t * id, $thread * thrd ) {
339 /* paranoid */ verify( thrd );
340 /* paranoid */ verify( thrd->state != Halted );
341 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
342 /* paranoid */ #if defined( __CFA_WITH_VERIFY__ )
343 /* paranoid */ if( thrd->state == Blocked || thrd->state == Start ) assertf( thrd->preempted == __NO_PREEMPTION,
344 "Error inactive thread marked as preempted, state %d, preemption %d\n", thrd->state, thrd->preempted );
345 /* paranoid */ if( thrd->preempted != __NO_PREEMPTION ) assertf(thrd->state == Active,
346 "Error preempted thread marked as not currently running, state %d, preemption %d\n", thrd->state, thrd->preempted );
347 /* paranoid */ #endif
348 /* paranoid */ verifyf( thrd->link.next == 0p, "Expected null got %p", thrd->link.next );
349
350 if (thrd->preempted == __NO_PREEMPTION) thrd->state = Ready;
351
352 ready_schedule_lock ( id );
353 push( thrd->curr_cluster, thrd );
354 __wake_one(id, thrd->curr_cluster);
355 ready_schedule_unlock( id );
356
357 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
358}
359
360// KERNEL ONLY
361static inline $thread * __next_thread(cluster * this) with( *this ) {
362 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
363
364 ready_schedule_lock ( (__processor_id_t*)kernelTLS.this_processor );
365 $thread * thrd = pop( this );
366 ready_schedule_unlock( (__processor_id_t*)kernelTLS.this_processor );
367
368 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
369 return thrd;
370}
371
372// KERNEL ONLY
373static inline $thread * __next_thread_slow(cluster * this) with( *this ) {
374 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
375
376 ready_schedule_lock ( (__processor_id_t*)kernelTLS.this_processor );
377 $thread * thrd = pop_slow( this );
378 ready_schedule_unlock( (__processor_id_t*)kernelTLS.this_processor );
379
380 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
381 return thrd;
382}
383
384// KERNEL ONLY unpark with out disabling interrupts
385void __unpark( struct __processor_id_t * id, $thread * thrd __cfaabi_dbg_ctx_param2 ) {
386 // record activity
387 __cfaabi_dbg_record_thrd( *thrd, false, caller );
388
389 int old_ticket = __atomic_fetch_add(&thrd->ticket, 1, __ATOMIC_SEQ_CST);
390 __cfaabi_dbg_debug_do( thrd->unpark_result = old_ticket; thrd->unpark_state = thrd->state; )
391 switch(old_ticket) {
392 case 1:
393 // Wake won the race, the thread will reschedule/rerun itself
394 break;
395 case 0:
396 /* paranoid */ verify( ! thrd->preempted != __NO_PREEMPTION );
397 /* paranoid */ verify( thrd->state == Blocked );
398
399 // Wake lost the race,
400 __schedule_thread( id, thrd );
401 break;
402 default:
403 // This makes no sense, something is wrong abort
404 abort();
405 }
406}
407
408void unpark( $thread * thrd __cfaabi_dbg_ctx_param2 ) {
409 if( !thrd ) return;
410
411 disable_interrupts();
412 __unpark( (__processor_id_t*)kernelTLS.this_processor, thrd __cfaabi_dbg_ctx_fwd2 );
413 enable_interrupts( __cfaabi_dbg_ctx );
414}
415
416void park( __cfaabi_dbg_ctx_param ) {
417 /* paranoid */ verify( kernelTLS.preemption_state.enabled );
418 disable_interrupts();
419 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
420 /* paranoid */ verify( kernelTLS.this_thread->preempted == __NO_PREEMPTION );
421
422 // record activity
423 __cfaabi_dbg_record_thrd( *kernelTLS.this_thread, true, caller );
424
425 returnToKernel();
426
427 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
428 enable_interrupts( __cfaabi_dbg_ctx );
429 /* paranoid */ verify( kernelTLS.preemption_state.enabled );
430
431}
432
433// KERNEL ONLY
434void __leave_thread() {
435 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
436 returnToKernel();
437 abort();
438}
439
440// KERNEL ONLY
441bool force_yield( __Preemption_Reason reason ) {
442 /* paranoid */ verify( kernelTLS.preemption_state.enabled );
443 disable_interrupts();
444 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
445
446 $thread * thrd = kernelTLS.this_thread;
447 /* paranoid */ verify(thrd->state == Active);
448
449 // SKULLDUGGERY: It is possible that we are preempting this thread just before
450 // it was going to park itself. If that is the case and it is already using the
451 // intrusive fields then we can't use them to preempt the thread
452 // If that is the case, abandon the preemption.
453 bool preempted = false;
454 if(thrd->link.next == 0p) {
455 preempted = true;
456 thrd->preempted = reason;
457 returnToKernel();
458 }
459
460 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
461 enable_interrupts_noPoll();
462 /* paranoid */ verify( kernelTLS.preemption_state.enabled );
463
464 return preempted;
465}
466
467//=============================================================================================
468// Kernel Idle Sleep
469//=============================================================================================
470// Wake a thread from the front if there are any
471static void __wake_one(struct __processor_id_t * id, cluster * this) {
472 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
473 /* paranoid */ verify( ready_schedule_islocked( id ) );
474
475 // Check if there is a sleeping processor
476 processor * p;
477 unsigned idle;
478 unsigned total;
479 [idle, total, p] = query(this->idles);
480
481 // If no one is sleeping, we are done
482 if( idle == 0 ) return;
483
484 // We found a processor, wake it up
485 post( p->idle );
486
487 #if !defined(__CFA_NO_STATISTICS__)
488 __tls_stats()->ready.sleep.wakes++;
489 #endif
490
491 /* paranoid */ verify( ready_schedule_islocked( id ) );
492 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
493
494 return;
495}
496
497// Unconditionnaly wake a thread
498void __wake_proc(processor * this) {
499 __cfadbg_print_safe(runtime_core, "Kernel : waking Processor %p\n", this);
500
501 disable_interrupts();
502 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
503 bool ret = post( this->idle );
504 enable_interrupts( __cfaabi_dbg_ctx );
505}
506
507static void push (__cluster_idles & this, processor & proc) {
508 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
509 lock( this );
510 this.idle++;
511 /* paranoid */ verify( this.idle <= this.total );
512
513 insert_first(this.list, proc);
514 unlock( this );
515 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
516}
517
518static void remove(__cluster_idles & this, processor & proc) {
519 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
520 lock( this );
521 this.idle--;
522 /* paranoid */ verify( this.idle >= 0 );
523
524 remove(proc);
525 unlock( this );
526 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
527}
528
529static [unsigned idle, unsigned total, * processor] query( & __cluster_idles this ) {
530 for() {
531 uint64_t l = __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST);
532 if( 1 == (l % 2) ) { Pause(); continue; }
533 unsigned idle = this.idle;
534 unsigned total = this.total;
535 processor * proc = &this.list`first;
536 // Compiler fence is unnecessary, but gcc-8 and older incorrectly reorder code without it
537 asm volatile("": : :"memory");
538 if(l != __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST)) { Pause(); continue; }
539 return [idle, total, proc];
540 }
541}
542
543//=============================================================================================
544// Unexpected Terminating logic
545//=============================================================================================
546static __spinlock_t kernel_abort_lock;
547static bool kernel_abort_called = false;
548
549void * kernel_abort(void) __attribute__ ((__nothrow__)) {
550 // abort cannot be recursively entered by the same or different processors because all signal handlers return when
551 // the globalAbort flag is true.
552 lock( kernel_abort_lock __cfaabi_dbg_ctx2 );
553
554 // first task to abort ?
555 if ( kernel_abort_called ) { // not first task to abort ?
556 unlock( kernel_abort_lock );
557
558 sigset_t mask;
559 sigemptyset( &mask );
560 sigaddset( &mask, SIGALRM ); // block SIGALRM signals
561 sigaddset( &mask, SIGUSR1 ); // block SIGALRM signals
562 sigsuspend( &mask ); // block the processor to prevent further damage during abort
563 _exit( EXIT_FAILURE ); // if processor unblocks before it is killed, terminate it
564 }
565 else {
566 kernel_abort_called = true;
567 unlock( kernel_abort_lock );
568 }
569
570 return kernelTLS.this_thread;
571}
572
573void kernel_abort_msg( void * kernel_data, char * abort_text, int abort_text_size ) {
574 $thread * thrd = ( $thread * ) kernel_data;
575
576 if(thrd) {
577 int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
578 __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
579
580 if ( &thrd->self_cor != thrd->curr_cor ) {
581 len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
582 __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
583 }
584 else {
585 __cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
586 }
587 }
588 else {
589 int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
590 __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
591 }
592}
593
594int kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
595 return get_coroutine(kernelTLS.this_thread) == get_coroutine(mainThread) ? 4 : 2;
596}
597
598static __spinlock_t kernel_debug_lock;
599
600extern "C" {
601 void __cfaabi_bits_acquire() {
602 lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
603 }
604
605 void __cfaabi_bits_release() {
606 unlock( kernel_debug_lock );
607 }
608}
609
610//=============================================================================================
611// Kernel Utilities
612//=============================================================================================
613//-----------------------------------------------------------------------------
614// Locks
615void ?{}( semaphore & this, int count = 1 ) {
616 (this.lock){};
617 this.count = count;
618 (this.waiting){};
619}
620void ^?{}(semaphore & this) {}
621
622bool P(semaphore & this) with( this ){
623 lock( lock __cfaabi_dbg_ctx2 );
624 count -= 1;
625 if ( count < 0 ) {
626 // queue current task
627 append( waiting, kernelTLS.this_thread );
628
629 // atomically release spin lock and block
630 unlock( lock );
631 park( __cfaabi_dbg_ctx );
632 return true;
633 }
634 else {
635 unlock( lock );
636 return false;
637 }
638}
639
640bool V(semaphore & this) with( this ) {
641 $thread * thrd = 0p;
642 lock( lock __cfaabi_dbg_ctx2 );
643 count += 1;
644 if ( count <= 0 ) {
645 // remove task at head of waiting list
646 thrd = pop_head( waiting );
647 }
648
649 unlock( lock );
650
651 // make new owner
652 unpark( thrd __cfaabi_dbg_ctx2 );
653
654 return thrd != 0p;
655}
656
657bool V(semaphore & this, unsigned diff) with( this ) {
658 $thread * thrd = 0p;
659 lock( lock __cfaabi_dbg_ctx2 );
660 int release = max(-count, (int)diff);
661 count += diff;
662 for(release) {
663 unpark( pop_head( waiting ) __cfaabi_dbg_ctx2 );
664 }
665
666 unlock( lock );
667
668 return thrd != 0p;
669}
670
671//-----------------------------------------------------------------------------
672// Debug
673__cfaabi_dbg_debug_do(
674 extern "C" {
675 void __cfaabi_dbg_record_lock(__spinlock_t & this, const char prev_name[]) {
676 this.prev_name = prev_name;
677 this.prev_thrd = kernelTLS.this_thread;
678 }
679
680 void __cfaabi_dbg_record_thrd($thread & this, bool park, const char prev_name[]) {
681 if(park) {
682 this.park_caller = prev_name;
683 this.park_stale = false;
684 }
685 else {
686 this.unpark_caller = prev_name;
687 this.unpark_stale = false;
688 }
689 }
690 }
691)
692
693//-----------------------------------------------------------------------------
694// Debug
695bool threading_enabled(void) __attribute__((const)) {
696 return true;
697}
698
699//-----------------------------------------------------------------------------
700// Statistics
701#if !defined(__CFA_NO_STATISTICS__)
702 void print_halts( processor & this ) {
703 this.print_halts = true;
704 }
705#endif
706// Local Variables: //
707// mode: c //
708// tab-width: 4 //
709// End: //
Note: See TracBrowser for help on using the repository browser.