source: libcfa/src/concurrency/kernel.cfa@ 7ab28b69

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 7ab28b69 was 58d64a4, checked in by Thierry Delisle <tdelisle@…>, 5 years 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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