source: libcfa/src/concurrency/kernel.cfa@ 2fab24e3

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 2fab24e3 was 4f449d2, checked in by Thierry Delisle <tdelisle@…>, 5 years ago

Fixed interted abort condition.
  • Property mode set to 100644
File size: 24.1 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 __cfaabi_tls.rand_seed ^= rdtscl();
125 __cfaabi_tls.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 #if !defined(__CFA_NO_STATISTICS__)
143 unsigned long long last_tally = rdtscl();
144 #endif
145
146
147 __cfadbg_print_safe(runtime_core, "Kernel : core %p started\n", this);
148
149 $thread * readyThread = 0p;
150 MAIN_LOOP:
151 for() {
152 // Try to get the next thread
153 readyThread = __next_thread( this->cltr );
154
155 if( !readyThread ) {
156 readyThread = __next_thread_slow( this->cltr );
157 }
158
159 HALT:
160 if( !readyThread ) {
161 // Don't block if we are done
162 if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
163
164 #if !defined(__CFA_NO_STATISTICS__)
165 __tls_stats()->ready.sleep.halts++;
166 #endif
167
168 // Push self to idle stack
169 push(this->cltr->idles, * this);
170
171 // Confirm the ready-queue is empty
172 readyThread = __next_thread_slow( this->cltr );
173 if( readyThread ) {
174 // A thread was found, cancel the halt
175 remove(this->cltr->idles, * this);
176
177 #if !defined(__CFA_NO_STATISTICS__)
178 __tls_stats()->ready.sleep.cancels++;
179 #endif
180
181 // continue the mai loop
182 break HALT;
183 }
184
185 #if !defined(__CFA_NO_STATISTICS__)
186 if(this->print_halts) {
187 __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 0\n", this->id, rdtscl());
188 }
189 #endif
190
191 wait( this->idle );
192
193 #if !defined(__CFA_NO_STATISTICS__)
194 if(this->print_halts) {
195 __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 1\n", this->id, rdtscl());
196 }
197 #endif
198
199 // We were woken up, remove self from idle
200 remove(this->cltr->idles, * this);
201
202 // DON'T just proceed, start looking again
203 continue MAIN_LOOP;
204 }
205
206 /* paranoid */ verify( readyThread );
207
208 // We found a thread run it
209 __run_thread(this, readyThread);
210
211 // Are we done?
212 if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
213
214 #if !defined(__CFA_NO_STATISTICS__)
215 unsigned long long curr = rdtscl();
216 if(curr > (last_tally + 500000000)) {
217 __tally_stats(this->cltr->stats, __cfaabi_tls.this_stats);
218 last_tally = curr;
219 }
220 #endif
221 }
222
223 __cfadbg_print_safe(runtime_core, "Kernel : core %p stopping\n", this);
224 }
225
226 V( this->terminated );
227
228 if(this == mainProcessor) {
229 // HACK : the coroutine context switch expects this_thread to be set
230 // and it make sense for it to be set in all other cases except here
231 // fake it
232 __cfaabi_tls.this_thread = mainThread;
233 }
234
235 __cfadbg_print_safe(runtime_core, "Kernel : core %p terminated\n", this);
236}
237
238static int * __volatile_errno() __attribute__((noinline));
239static int * __volatile_errno() { asm(""); return &errno; }
240
241// KERNEL ONLY
242// runThread runs a thread by context switching
243// from the processor coroutine to the target thread
244static void __run_thread(processor * this, $thread * thrd_dst) {
245 /* paranoid */ verify( ! __preemption_enabled() );
246 /* paranoid */ verifyf( thrd_dst->state == Ready || thrd_dst->preempted != __NO_PREEMPTION, "state : %d, preempted %d\n", thrd_dst->state, thrd_dst->preempted);
247 /* paranoid */ verifyf( thrd_dst->link.next == 0p, "Expected null got %p", thrd_dst->link.next );
248 __builtin_prefetch( thrd_dst->context.SP );
249
250 $coroutine * proc_cor = get_coroutine(this->runner);
251
252 // set state of processor coroutine to inactive
253 verify(proc_cor->state == Active);
254 proc_cor->state = Blocked;
255
256 // Actually run the thread
257 RUNNING: while(true) {
258 thrd_dst->preempted = __NO_PREEMPTION;
259 thrd_dst->state = Active;
260
261 // Update global state
262 kernelTLS().this_thread = thrd_dst;
263
264 /* paranoid */ verify( ! __preemption_enabled() );
265 /* paranoid */ verify( kernelTLS().this_thread == thrd_dst );
266 /* paranoid */ verify( thrd_dst->curr_cluster == this->cltr );
267 /* paranoid */ verify( thrd_dst->context.SP );
268 /* paranoid */ verify( thrd_dst->state != Halted );
269 /* 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
270 /* 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
271 /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_dst->canary );
272
273
274
275 // set context switch to the thread that the processor is executing
276 __cfactx_switch( &proc_cor->context, &thrd_dst->context );
277 // when __cfactx_switch returns we are back in the processor coroutine
278
279 /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_dst->canary );
280 /* 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 );
281 /* 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 );
282 /* paranoid */ verify( thrd_dst->context.SP );
283 /* paranoid */ verify( thrd_dst->curr_cluster == this->cltr );
284 /* paranoid */ verify( kernelTLS().this_thread == thrd_dst );
285 /* paranoid */ verify( ! __preemption_enabled() );
286
287 // Reset global state
288 kernelTLS().this_thread = 0p;
289
290 // We just finished running a thread, there are a few things that could have happened.
291 // 1 - Regular case : the thread has blocked and now one has scheduled it yet.
292 // 2 - Racy case : the thread has blocked but someone has already tried to schedule it.
293 // 4 - Preempted
294 // In case 1, we may have won a race so we can't write to the state again.
295 // In case 2, we lost the race so we now own the thread.
296
297 if(unlikely(thrd_dst->preempted != __NO_PREEMPTION)) {
298 // The thread was preempted, reschedule it and reset the flag
299 __schedule_thread( thrd_dst );
300 break RUNNING;
301 }
302
303 if(unlikely(thrd_dst->state == Halting)) {
304 // The thread has halted, it should never be scheduled/run again
305 // finish the thread
306 __thread_finish( thrd_dst );
307 break RUNNING;
308 }
309
310 /* paranoid */ verify( thrd_dst->state == Active );
311 thrd_dst->state = Blocked;
312
313 // set state of processor coroutine to active and the thread to inactive
314 int old_ticket = __atomic_fetch_sub(&thrd_dst->ticket, 1, __ATOMIC_SEQ_CST);
315 switch(old_ticket) {
316 case TICKET_RUNNING:
317 // This is case 1, the regular case, nothing more is needed
318 break RUNNING;
319 case TICKET_UNBLOCK:
320 // This is case 2, the racy case, someone tried to run this thread before it finished blocking
321 // In this case, just run it again.
322 continue RUNNING;
323 default:
324 // This makes no sense, something is wrong abort
325 abort();
326 }
327 }
328
329 // Just before returning to the processor, set the processor coroutine to active
330 proc_cor->state = Active;
331
332 /* paranoid */ verify( ! __preemption_enabled() );
333}
334
335// KERNEL_ONLY
336void returnToKernel() {
337 /* paranoid */ verify( ! __preemption_enabled() );
338 $coroutine * proc_cor = get_coroutine(kernelTLS().this_processor->runner);
339 $thread * thrd_src = kernelTLS().this_thread;
340
341 #if !defined(__CFA_NO_STATISTICS__)
342 struct processor * last_proc = kernelTLS().this_processor;
343 #endif
344
345 // Run the thread on this processor
346 {
347 int local_errno = *__volatile_errno();
348 #if defined( __i386 ) || defined( __x86_64 )
349 __x87_store;
350 #endif
351 /* paranoid */ verify( proc_cor->context.SP );
352 /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_src->canary );
353 __cfactx_switch( &thrd_src->context, &proc_cor->context );
354 /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd_src->canary );
355 #if defined( __i386 ) || defined( __x86_64 )
356 __x87_load;
357 #endif
358 *__volatile_errno() = local_errno;
359 }
360
361 #if !defined(__CFA_NO_STATISTICS__)
362 if(last_proc != kernelTLS().this_processor) {
363 __tls_stats()->ready.threads.migration++;
364 }
365 #endif
366
367 /* paranoid */ verify( ! __preemption_enabled() );
368 /* 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 );
369 /* 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 );
370}
371
372//-----------------------------------------------------------------------------
373// Scheduler routines
374// KERNEL ONLY
375void __schedule_thread( $thread * thrd ) {
376 /* paranoid */ verify( ! __preemption_enabled() );
377 /* paranoid */ verify( kernelTLS().this_proc_id );
378 /* paranoid */ verify( thrd );
379 /* paranoid */ verify( thrd->state != Halted );
380 /* paranoid */ verify( thrd->curr_cluster );
381 /* paranoid */ #if defined( __CFA_WITH_VERIFY__ )
382 /* paranoid */ if( thrd->state == Blocked || thrd->state == Start ) assertf( thrd->preempted == __NO_PREEMPTION,
383 "Error inactive thread marked as preempted, state %d, preemption %d\n", thrd->state, thrd->preempted );
384 /* paranoid */ if( thrd->preempted != __NO_PREEMPTION ) assertf(thrd->state == Active,
385 "Error preempted thread marked as not currently running, state %d, preemption %d\n", thrd->state, thrd->preempted );
386 /* paranoid */ #endif
387 /* paranoid */ verifyf( thrd->link.next == 0p, "Expected null got %p", thrd->link.next );
388 /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd->canary );
389
390
391 if (thrd->preempted == __NO_PREEMPTION) thrd->state = Ready;
392
393 ready_schedule_lock();
394 // Dereference the thread now because once we push it, there is not guaranteed it's still valid.
395 struct cluster * cl = thrd->curr_cluster;
396
397 // push the thread to the cluster ready-queue
398 push( cl, thrd );
399
400 // variable thrd is no longer safe to use
401
402 // wake the cluster using the save variable.
403 __wake_one( cl );
404 ready_schedule_unlock();
405
406 /* paranoid */ verify( ! __preemption_enabled() );
407}
408
409// KERNEL ONLY
410static inline $thread * __next_thread(cluster * this) with( *this ) {
411 /* paranoid */ verify( ! __preemption_enabled() );
412 /* paranoid */ verify( kernelTLS().this_proc_id );
413
414 ready_schedule_lock();
415 $thread * thrd = pop( this );
416 ready_schedule_unlock();
417
418 /* paranoid */ verify( kernelTLS().this_proc_id );
419 /* paranoid */ verify( ! __preemption_enabled() );
420 return thrd;
421}
422
423// KERNEL ONLY
424static inline $thread * __next_thread_slow(cluster * this) with( *this ) {
425 /* paranoid */ verify( ! __preemption_enabled() );
426 /* paranoid */ verify( kernelTLS().this_proc_id );
427
428 ready_schedule_lock();
429 $thread * thrd = pop_slow( this );
430 ready_schedule_unlock();
431
432 /* paranoid */ verify( kernelTLS().this_proc_id );
433 /* paranoid */ verify( ! __preemption_enabled() );
434 return thrd;
435}
436
437void unpark( $thread * thrd ) {
438 if( !thrd ) return;
439
440 int old_ticket = __atomic_fetch_add(&thrd->ticket, 1, __ATOMIC_SEQ_CST);
441 switch(old_ticket) {
442 case TICKET_RUNNING:
443 // Wake won the race, the thread will reschedule/rerun itself
444 break;
445 case TICKET_BLOCKED:
446 /* paranoid */ verify( ! thrd->preempted != __NO_PREEMPTION );
447 /* paranoid */ verify( thrd->state == Blocked );
448
449 {
450 /* paranoid */ verify( publicTLS_get(this_proc_id) );
451 bool full = publicTLS_get(this_proc_id)->full_proc;
452 if(full) disable_interrupts();
453
454 /* paranoid */ verify( ! __preemption_enabled() );
455
456 // Wake lost the race,
457 __schedule_thread( thrd );
458
459 /* paranoid */ verify( ! __preemption_enabled() );
460
461 if(full) enable_interrupts( __cfaabi_dbg_ctx );
462 /* paranoid */ verify( publicTLS_get(this_proc_id) );
463 }
464
465 break;
466 default:
467 // This makes no sense, something is wrong abort
468 abort("Thread %p (%s) has mismatch park/unpark\n", thrd, thrd->self_cor.name);
469 }
470}
471
472void park( void ) {
473 /* paranoid */ verify( __preemption_enabled() );
474 disable_interrupts();
475 /* paranoid */ verify( ! __preemption_enabled() );
476 /* paranoid */ verify( kernelTLS().this_thread->preempted == __NO_PREEMPTION );
477
478 returnToKernel();
479
480 /* paranoid */ verify( ! __preemption_enabled() );
481 enable_interrupts( __cfaabi_dbg_ctx );
482 /* paranoid */ verify( __preemption_enabled() );
483
484}
485
486extern "C" {
487 // Leave the thread monitor
488 // last routine called by a thread.
489 // Should never return
490 void __cfactx_thrd_leave() {
491 $thread * thrd = active_thread();
492 $monitor * this = &thrd->self_mon;
493
494 // Lock the monitor now
495 lock( this->lock __cfaabi_dbg_ctx2 );
496
497 disable_interrupts();
498
499 /* paranoid */ verify( ! __preemption_enabled() );
500 /* paranoid */ verify( thrd->state == Active );
501 /* paranoid */ verify( 0x0D15EA5E0D15EA5Ep == thrd->canary );
502 /* paranoid */ verify( kernelTLS().this_thread == thrd );
503 /* paranoid */ verify( thrd->context.SP );
504 /* paranoid */ verifyf( ((uintptr_t)thrd->context.SP) > ((uintptr_t)__get_stack(thrd->curr_cor)->limit), "ERROR : $thread %p has been corrupted.\n StackPointer too large.\n", thrd );
505 /* paranoid */ verifyf( ((uintptr_t)thrd->context.SP) < ((uintptr_t)__get_stack(thrd->curr_cor)->base ), "ERROR : $thread %p has been corrupted.\n StackPointer too small.\n", thrd );
506
507 thrd->state = Halting;
508 if( TICKET_RUNNING != thrd->ticket ) { abort( "Thread terminated with pending unpark" ); }
509 if( thrd != this->owner ) { abort( "Thread internal monitor has incorrect owner" ); }
510 if( this->recursion != 1) { abort( "Thread internal monitor has unbalanced recursion" ); }
511
512 // Leave the thread
513 returnToKernel();
514
515 // Control flow should never reach here!
516 abort();
517 }
518}
519
520// KERNEL ONLY
521bool force_yield( __Preemption_Reason reason ) {
522 /* paranoid */ verify( __preemption_enabled() );
523 disable_interrupts();
524 /* paranoid */ verify( ! __preemption_enabled() );
525
526 $thread * thrd = kernelTLS().this_thread;
527 /* paranoid */ verify(thrd->state == Active);
528
529 // SKULLDUGGERY: It is possible that we are preempting this thread just before
530 // it was going to park itself. If that is the case and it is already using the
531 // intrusive fields then we can't use them to preempt the thread
532 // If that is the case, abandon the preemption.
533 bool preempted = false;
534 if(thrd->link.next == 0p) {
535 preempted = true;
536 thrd->preempted = reason;
537 returnToKernel();
538 }
539
540 /* paranoid */ verify( ! __preemption_enabled() );
541 enable_interrupts_noPoll();
542 /* paranoid */ verify( __preemption_enabled() );
543
544 return preempted;
545}
546
547//=============================================================================================
548// Kernel Idle Sleep
549//=============================================================================================
550// Wake a thread from the front if there are any
551static void __wake_one(cluster * this) {
552 /* paranoid */ verify( ! __preemption_enabled() );
553 /* paranoid */ verify( ready_schedule_islocked() );
554
555 // Check if there is a sleeping processor
556 processor * p;
557 unsigned idle;
558 unsigned total;
559 [idle, total, p] = query(this->idles);
560
561 // If no one is sleeping, we are done
562 if( idle == 0 ) return;
563
564 // We found a processor, wake it up
565 post( p->idle );
566
567 #if !defined(__CFA_NO_STATISTICS__)
568 __tls_stats()->ready.sleep.wakes++;
569 #endif
570
571 /* paranoid */ verify( ready_schedule_islocked() );
572 /* paranoid */ verify( ! __preemption_enabled() );
573
574 return;
575}
576
577// Unconditionnaly wake a thread
578void __wake_proc(processor * this) {
579 __cfadbg_print_safe(runtime_core, "Kernel : waking Processor %p\n", this);
580
581 disable_interrupts();
582 /* paranoid */ verify( ! __preemption_enabled() );
583 post( this->idle );
584 enable_interrupts( __cfaabi_dbg_ctx );
585}
586
587static void push (__cluster_idles & this, processor & proc) {
588 /* paranoid */ verify( ! __preemption_enabled() );
589 lock( this );
590 this.idle++;
591 /* paranoid */ verify( this.idle <= this.total );
592
593 insert_first(this.list, proc);
594 unlock( this );
595 /* paranoid */ verify( ! __preemption_enabled() );
596}
597
598static void remove(__cluster_idles & this, processor & proc) {
599 /* paranoid */ verify( ! __preemption_enabled() );
600 lock( this );
601 this.idle--;
602 /* paranoid */ verify( this.idle >= 0 );
603
604 remove(proc);
605 unlock( this );
606 /* paranoid */ verify( ! __preemption_enabled() );
607}
608
609static [unsigned idle, unsigned total, * processor] query( & __cluster_idles this ) {
610 for() {
611 uint64_t l = __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST);
612 if( 1 == (l % 2) ) { Pause(); continue; }
613 unsigned idle = this.idle;
614 unsigned total = this.total;
615 processor * proc = &this.list`first;
616 // Compiler fence is unnecessary, but gcc-8 and older incorrectly reorder code without it
617 asm volatile("": : :"memory");
618 if(l != __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST)) { Pause(); continue; }
619 return [idle, total, proc];
620 }
621}
622
623//=============================================================================================
624// Unexpected Terminating logic
625//=============================================================================================
626
627extern "C" {
628 extern void __cfaabi_real_abort(void);
629}
630static volatile bool kernel_abort_called = false;
631
632void * kernel_abort(void) __attribute__ ((__nothrow__)) {
633 // abort cannot be recursively entered by the same or different processors because all signal handlers return when
634 // the globalAbort flag is true.
635 bool first = !__atomic_test_and_set( &kernel_abort_called, __ATOMIC_SEQ_CST);
636
637 // first task to abort ?
638 if ( !first ) {
639 // We aren't the first to abort.
640 // I give up, just let C handle it
641 __cfaabi_real_abort();
642 }
643
644 // disable interrupts, it no longer makes sense to try to interrupt this processor
645 disable_interrupts();
646
647 return __cfaabi_tls.this_thread;
648}
649
650void kernel_abort_msg( void * kernel_data, char * abort_text, int abort_text_size ) {
651 $thread * thrd = ( $thread * ) kernel_data;
652
653 if(thrd) {
654 int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
655 __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
656
657 if ( &thrd->self_cor != thrd->curr_cor ) {
658 len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
659 __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
660 }
661 else {
662 __cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
663 }
664 }
665 else {
666 int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
667 __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
668 }
669}
670
671int kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
672 return get_coroutine(kernelTLS().this_thread) == get_coroutine(mainThread) ? 4 : 2;
673}
674
675static __spinlock_t kernel_debug_lock;
676
677extern "C" {
678 void __cfaabi_bits_acquire() {
679 lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
680 }
681
682 void __cfaabi_bits_release() {
683 unlock( kernel_debug_lock );
684 }
685}
686
687//=============================================================================================
688// Kernel Utilities
689//=============================================================================================
690//-----------------------------------------------------------------------------
691// Locks
692void ?{}( semaphore & this, int count = 1 ) {
693 (this.lock){};
694 this.count = count;
695 (this.waiting){};
696}
697void ^?{}(semaphore & this) {}
698
699bool P(semaphore & this) with( this ){
700 lock( lock __cfaabi_dbg_ctx2 );
701 count -= 1;
702 if ( count < 0 ) {
703 // queue current task
704 append( waiting, active_thread() );
705
706 // atomically release spin lock and block
707 unlock( lock );
708 park();
709 return true;
710 }
711 else {
712 unlock( lock );
713 return false;
714 }
715}
716
717bool V(semaphore & this) with( this ) {
718 $thread * thrd = 0p;
719 lock( lock __cfaabi_dbg_ctx2 );
720 count += 1;
721 if ( count <= 0 ) {
722 // remove task at head of waiting list
723 thrd = pop_head( waiting );
724 }
725
726 unlock( lock );
727
728 // make new owner
729 unpark( thrd );
730
731 return thrd != 0p;
732}
733
734bool V(semaphore & this, unsigned diff) with( this ) {
735 $thread * thrd = 0p;
736 lock( lock __cfaabi_dbg_ctx2 );
737 int release = max(-count, (int)diff);
738 count += diff;
739 for(release) {
740 unpark( pop_head( waiting ) );
741 }
742
743 unlock( lock );
744
745 return thrd != 0p;
746}
747
748//-----------------------------------------------------------------------------
749// Debug
750__cfaabi_dbg_debug_do(
751 extern "C" {
752 void __cfaabi_dbg_record_lock(__spinlock_t & this, const char prev_name[]) {
753 this.prev_name = prev_name;
754 this.prev_thrd = kernelTLS().this_thread;
755 }
756 }
757)
758
759//-----------------------------------------------------------------------------
760// Debug
761bool threading_enabled(void) __attribute__((const)) {
762 return true;
763}
764
765//-----------------------------------------------------------------------------
766// Statistics
767#if !defined(__CFA_NO_STATISTICS__)
768 void print_halts( processor & this ) {
769 this.print_halts = true;
770 }
771
772 void print_stats_now( cluster & this, int flags ) {
773 __print_stats( this.stats, this.print_stats, "Cluster", this.name, (void*)&this );
774 }
775
776 extern int __print_alarm_stats;
777 void print_alarm_stats() {
778 __print_alarm_stats = -1;
779 }
780#endif
781// Local Variables: //
782// mode: c //
783// tab-width: 4 //
784// End: //
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