source: libcfa/src/concurrency/kernel.cfa@ e873838

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 e873838 was e873838, checked in by Thierry Delisle <tdelisle@…>, 5 years ago

Removed unpark and added support for unpark from the kernel (removing the distinction between the two
  • Property mode set to 100644
File size: 22.9 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(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 // Update global state
249 kernelTLS.this_thread = thrd_dst;
250
251 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
252 /* paranoid */ verify( kernelTLS.this_thread == thrd_dst );
253 /* paranoid */ verify( thrd_dst->context.SP );
254 /* paranoid */ verify( thrd_dst->state != Halted );
255 /* 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
256 /* 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
257 /* paranoid */ verify( 0x0D15EA5E0D15EA5E == thrd_dst->canary );
258
259
260
261 // set context switch to the thread that the processor is executing
262 __cfactx_switch( &proc_cor->context, &thrd_dst->context );
263 // when __cfactx_switch returns we are back in the processor coroutine
264
265 /* paranoid */ verify( 0x0D15EA5E0D15EA5E == thrd_dst->canary );
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( thrd_dst->context.SP );
269 /* paranoid */ verify( kernelTLS.this_thread == thrd_dst );
270 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
271
272 // Reset global state
273 kernelTLS.this_thread = 0p;
274
275 // We just finished running a thread, there are a few things that could have happened.
276 // 1 - Regular case : the thread has blocked and now one has scheduled it yet.
277 // 2 - Racy case : the thread has blocked but someone has already tried to schedule it.
278 // 4 - Preempted
279 // In case 1, we may have won a race so we can't write to the state again.
280 // In case 2, we lost the race so we now own the thread.
281
282 if(unlikely(thrd_dst->preempted != __NO_PREEMPTION)) {
283 // The thread was preempted, reschedule it and reset the flag
284 __schedule_thread( thrd_dst );
285 break RUNNING;
286 }
287
288 if(unlikely(thrd_dst->state == Halted)) {
289 // The thread has halted, it should never be scheduled/run again
290 // finish the thread
291 __thread_finish( thrd_dst );
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 switch(old_ticket) {
301 case TICKET_RUNNING:
302 // This is case 1, the regular case, nothing more is needed
303 break RUNNING;
304 case TICKET_UNBLOCK:
305 // This is case 2, the racy case, someone tried to run this thread before it finished blocking
306 // In this case, just run it again.
307 continue RUNNING;
308 default:
309 // This makes no sense, something is wrong abort
310 abort();
311 }
312 }
313
314 // Just before returning to the processor, set the processor coroutine to active
315 proc_cor->state = Active;
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 /* paranoid */ verify( proc_cor->context.SP );
337 /* paranoid */ verify( 0x0D15EA5E0D15EA5E == thrd_src->canary );
338 __cfactx_switch( &thrd_src->context, &proc_cor->context );
339 /* paranoid */ verify( 0x0D15EA5E0D15EA5E == thrd_src->canary );
340 #if defined( __i386 ) || defined( __x86_64 )
341 __x87_load;
342 #endif
343 *__volatile_errno() = local_errno;
344 }
345
346 #if !defined(__CFA_NO_STATISTICS__)
347 if(last_proc != kernelTLS.this_processor) {
348 __tls_stats()->ready.threads.migration++;
349 }
350 #endif
351
352 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
353 /* 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 );
354 /* 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 );
355}
356
357//-----------------------------------------------------------------------------
358// Scheduler routines
359// KERNEL ONLY
360void __schedule_thread( $thread * thrd ) {
361 /* paranoid */ verify( thrd );
362 /* paranoid */ verify( thrd->state != Halted );
363 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
364 /* paranoid */ verify( kernelTLS.this_proc_id );
365 /* paranoid */ #if defined( __CFA_WITH_VERIFY__ )
366 /* paranoid */ if( thrd->state == Blocked || thrd->state == Start ) assertf( thrd->preempted == __NO_PREEMPTION,
367 "Error inactive thread marked as preempted, state %d, preemption %d\n", thrd->state, thrd->preempted );
368 /* paranoid */ if( thrd->preempted != __NO_PREEMPTION ) assertf(thrd->state == Active,
369 "Error preempted thread marked as not currently running, state %d, preemption %d\n", thrd->state, thrd->preempted );
370 /* paranoid */ #endif
371 /* paranoid */ verifyf( thrd->link.next == 0p, "Expected null got %p", thrd->link.next );
372 /* paranoid */ verify( 0x0D15EA5E0D15EA5E == thrd->canary );
373
374
375 if (thrd->preempted == __NO_PREEMPTION) thrd->state = Ready;
376
377 ready_schedule_lock();
378 push( thrd->curr_cluster, thrd );
379 __wake_one(thrd->curr_cluster);
380 ready_schedule_unlock();
381
382 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
383}
384
385// KERNEL ONLY
386static inline $thread * __next_thread(cluster * this) with( *this ) {
387 /* paranoid */ verify( kernelTLS.this_proc_id );
388 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
389
390 ready_schedule_lock();
391 $thread * thrd = pop( this );
392 ready_schedule_unlock();
393
394 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
395 /* paranoid */ verify( kernelTLS.this_proc_id );
396 return thrd;
397}
398
399// KERNEL ONLY
400static inline $thread * __next_thread_slow(cluster * this) with( *this ) {
401 /* paranoid */ verify( kernelTLS.this_proc_id );
402 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
403
404 ready_schedule_lock();
405 $thread * thrd = pop_slow( this );
406 ready_schedule_unlock();
407
408 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
409 /* paranoid */ verify( kernelTLS.this_proc_id );
410 return thrd;
411}
412
413void unpark( $thread * thrd ) {
414 if( !thrd ) return;
415
416 /* paranoid */ verify( kernelTLS.this_proc_id );
417 bool full = kernelTLS.this_proc_id->full_proc;
418 if(full) disable_interrupts();
419
420 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
421 int old_ticket = __atomic_fetch_add(&thrd->ticket, 1, __ATOMIC_SEQ_CST);
422 switch(old_ticket) {
423 case TICKET_RUNNING:
424 // Wake won the race, the thread will reschedule/rerun itself
425 break;
426 case TICKET_BLOCKED:
427 /* paranoid */ verify( ! thrd->preempted != __NO_PREEMPTION );
428 /* paranoid */ verify( thrd->state == Blocked );
429
430 // Wake lost the race,
431 __schedule_thread( thrd );
432 break;
433 default:
434 // This makes no sense, something is wrong abort
435 abort("Thread %p (%s) has mismatch park/unpark\n", thrd, thrd->self_cor.name);
436 }
437 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
438
439 if(full) enable_interrupts( __cfaabi_dbg_ctx );
440 /* paranoid */ verify( kernelTLS.this_proc_id );
441}
442
443void park( void ) {
444 /* paranoid */ verify( kernelTLS.preemption_state.enabled );
445 disable_interrupts();
446 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
447 /* paranoid */ verify( kernelTLS.this_thread->preempted == __NO_PREEMPTION );
448
449 returnToKernel();
450
451 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
452 enable_interrupts( __cfaabi_dbg_ctx );
453 /* paranoid */ verify( kernelTLS.preemption_state.enabled );
454
455}
456
457extern "C" {
458 // Leave the thread monitor
459 // last routine called by a thread.
460 // Should never return
461 void __cfactx_thrd_leave() {
462 $thread * thrd = TL_GET( this_thread );
463 $monitor * this = &thrd->self_mon;
464
465 // Lock the monitor now
466 lock( this->lock __cfaabi_dbg_ctx2 );
467
468 disable_interrupts();
469
470 thrd->state = Halted;
471
472 if( thrd != this->owner || this->recursion != 1) { abort( "Thread internal monitor has unbalanced recursion" ); }
473
474 // Leave the thread
475 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
476 returnToKernel();
477 abort();
478
479 // Control flow should never reach here!
480 }
481}
482
483// KERNEL ONLY
484bool force_yield( __Preemption_Reason reason ) {
485 /* paranoid */ verify( kernelTLS.preemption_state.enabled );
486 disable_interrupts();
487 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
488
489 $thread * thrd = kernelTLS.this_thread;
490 /* paranoid */ verify(thrd->state == Active);
491
492 // SKULLDUGGERY: It is possible that we are preempting this thread just before
493 // it was going to park itself. If that is the case and it is already using the
494 // intrusive fields then we can't use them to preempt the thread
495 // If that is the case, abandon the preemption.
496 bool preempted = false;
497 if(thrd->link.next == 0p) {
498 preempted = true;
499 thrd->preempted = reason;
500 returnToKernel();
501 }
502
503 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
504 enable_interrupts_noPoll();
505 /* paranoid */ verify( kernelTLS.preemption_state.enabled );
506
507 return preempted;
508}
509
510//=============================================================================================
511// Kernel Idle Sleep
512//=============================================================================================
513// Wake a thread from the front if there are any
514static void __wake_one(cluster * this) {
515 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
516 /* paranoid */ verify( ready_schedule_islocked() );
517
518 // Check if there is a sleeping processor
519 processor * p;
520 unsigned idle;
521 unsigned total;
522 [idle, total, p] = query(this->idles);
523
524 // If no one is sleeping, we are done
525 if( idle == 0 ) return;
526
527 // We found a processor, wake it up
528 post( p->idle );
529
530 #if !defined(__CFA_NO_STATISTICS__)
531 __tls_stats()->ready.sleep.wakes++;
532 #endif
533
534 /* paranoid */ verify( ready_schedule_islocked() );
535 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
536
537 return;
538}
539
540// Unconditionnaly wake a thread
541void __wake_proc(processor * this) {
542 __cfadbg_print_safe(runtime_core, "Kernel : waking Processor %p\n", this);
543
544 disable_interrupts();
545 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
546 post( this->idle );
547 enable_interrupts( __cfaabi_dbg_ctx );
548}
549
550static void push (__cluster_idles & this, processor & proc) {
551 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
552 lock( this );
553 this.idle++;
554 /* paranoid */ verify( this.idle <= this.total );
555
556 insert_first(this.list, proc);
557 unlock( this );
558 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
559}
560
561static void remove(__cluster_idles & this, processor & proc) {
562 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
563 lock( this );
564 this.idle--;
565 /* paranoid */ verify( this.idle >= 0 );
566
567 remove(proc);
568 unlock( this );
569 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
570}
571
572static [unsigned idle, unsigned total, * processor] query( & __cluster_idles this ) {
573 for() {
574 uint64_t l = __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST);
575 if( 1 == (l % 2) ) { Pause(); continue; }
576 unsigned idle = this.idle;
577 unsigned total = this.total;
578 processor * proc = &this.list`first;
579 // Compiler fence is unnecessary, but gcc-8 and older incorrectly reorder code without it
580 asm volatile("": : :"memory");
581 if(l != __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST)) { Pause(); continue; }
582 return [idle, total, proc];
583 }
584}
585
586//=============================================================================================
587// Unexpected Terminating logic
588//=============================================================================================
589static __spinlock_t kernel_abort_lock;
590static bool kernel_abort_called = false;
591
592void * kernel_abort(void) __attribute__ ((__nothrow__)) {
593 // abort cannot be recursively entered by the same or different processors because all signal handlers return when
594 // the globalAbort flag is true.
595 lock( kernel_abort_lock __cfaabi_dbg_ctx2 );
596
597 // first task to abort ?
598 if ( kernel_abort_called ) { // not first task to abort ?
599 unlock( kernel_abort_lock );
600
601 sigset_t mask;
602 sigemptyset( &mask );
603 sigaddset( &mask, SIGALRM ); // block SIGALRM signals
604 sigaddset( &mask, SIGUSR1 ); // block SIGALRM signals
605 sigsuspend( &mask ); // block the processor to prevent further damage during abort
606 _exit( EXIT_FAILURE ); // if processor unblocks before it is killed, terminate it
607 }
608 else {
609 kernel_abort_called = true;
610 unlock( kernel_abort_lock );
611 }
612
613 return kernelTLS.this_thread;
614}
615
616void kernel_abort_msg( void * kernel_data, char * abort_text, int abort_text_size ) {
617 $thread * thrd = ( $thread * ) kernel_data;
618
619 if(thrd) {
620 int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
621 __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
622
623 if ( &thrd->self_cor != thrd->curr_cor ) {
624 len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
625 __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
626 }
627 else {
628 __cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
629 }
630 }
631 else {
632 int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
633 __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
634 }
635}
636
637int kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
638 return get_coroutine(kernelTLS.this_thread) == get_coroutine(mainThread) ? 4 : 2;
639}
640
641static __spinlock_t kernel_debug_lock;
642
643extern "C" {
644 void __cfaabi_bits_acquire() {
645 lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
646 }
647
648 void __cfaabi_bits_release() {
649 unlock( kernel_debug_lock );
650 }
651}
652
653//=============================================================================================
654// Kernel Utilities
655//=============================================================================================
656//-----------------------------------------------------------------------------
657// Locks
658void ?{}( semaphore & this, int count = 1 ) {
659 (this.lock){};
660 this.count = count;
661 (this.waiting){};
662}
663void ^?{}(semaphore & this) {}
664
665bool P(semaphore & this) with( this ){
666 lock( lock __cfaabi_dbg_ctx2 );
667 count -= 1;
668 if ( count < 0 ) {
669 // queue current task
670 append( waiting, kernelTLS.this_thread );
671
672 // atomically release spin lock and block
673 unlock( lock );
674 park();
675 return true;
676 }
677 else {
678 unlock( lock );
679 return false;
680 }
681}
682
683bool V(semaphore & this) with( this ) {
684 $thread * thrd = 0p;
685 lock( lock __cfaabi_dbg_ctx2 );
686 count += 1;
687 if ( count <= 0 ) {
688 // remove task at head of waiting list
689 thrd = pop_head( waiting );
690 }
691
692 unlock( lock );
693
694 // make new owner
695 unpark( thrd );
696
697 return thrd != 0p;
698}
699
700bool V(semaphore & this, unsigned diff) with( this ) {
701 $thread * thrd = 0p;
702 lock( lock __cfaabi_dbg_ctx2 );
703 int release = max(-count, (int)diff);
704 count += diff;
705 for(release) {
706 unpark( pop_head( waiting ) );
707 }
708
709 unlock( lock );
710
711 return thrd != 0p;
712}
713
714//-----------------------------------------------------------------------------
715// Debug
716__cfaabi_dbg_debug_do(
717 extern "C" {
718 void __cfaabi_dbg_record_lock(__spinlock_t & this, const char prev_name[]) {
719 this.prev_name = prev_name;
720 this.prev_thrd = kernelTLS.this_thread;
721 }
722 }
723)
724
725//-----------------------------------------------------------------------------
726// Debug
727bool threading_enabled(void) __attribute__((const)) {
728 return true;
729}
730
731//-----------------------------------------------------------------------------
732// Statistics
733#if !defined(__CFA_NO_STATISTICS__)
734 void print_halts( processor & this ) {
735 this.print_halts = true;
736 }
737#endif
738// Local Variables: //
739// mode: c //
740// tab-width: 4 //
741// End: //
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