source: libcfa/src/concurrency/kernel.cfa@ 1a3040c

ADT arm-eh ast-experimental enum forall-pointer-decay jacob/cs343-translation jenkins-sandbox new-ast new-ast-unique-expr pthread-emulation qualifiedEnum
Last change on this file since 1a3040c was 1a3040c, checked in by Peter A. Buhr <pabuhr@…>, 6 years ago

add guard page to pthread stack in debug mode
  • Property mode set to 100644
File size: 27.9 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 : Tue Dec 3 21:46:54 2019
13// Update Count : 49
14//
15
16#define __cforall_thread__
17
18//C Includes
19#include <stddef.h>
20#include <errno.h>
21#include <string.h>
22extern "C" {
23#include <stdio.h>
24#include <fenv.h>
25#include <sys/resource.h>
26#include <signal.h>
27#include <unistd.h>
28#include <limits.h> // PTHREAD_STACK_MIN
29#include <sys/mman.h> // mprotect
30}
31
32//CFA Includes
33#include "time.hfa"
34#include "kernel_private.hfa"
35#include "preemption.hfa"
36#include "startup.hfa"
37
38//Private includes
39#define __CFA_INVOKE_PRIVATE__
40#include "invoke.h"
41
42//-----------------------------------------------------------------------------
43// Some assembly required
44#if defined( __i386 )
45 #define CtxGet( ctx ) \
46 __asm__ volatile ( \
47 "movl %%esp,%0\n"\
48 "movl %%ebp,%1\n"\
49 : "=rm" (ctx.SP),\
50 "=rm" (ctx.FP) \
51 )
52
53 // mxcr : SSE Status and Control bits (control bits are preserved across function calls)
54 // fcw : X87 FPU control word (preserved across function calls)
55 #define __x87_store \
56 uint32_t __mxcr; \
57 uint16_t __fcw; \
58 __asm__ volatile ( \
59 "stmxcsr %0\n" \
60 "fnstcw %1\n" \
61 : "=m" (__mxcr),\
62 "=m" (__fcw) \
63 )
64
65 #define __x87_load \
66 __asm__ volatile ( \
67 "fldcw %1\n" \
68 "ldmxcsr %0\n" \
69 ::"m" (__mxcr),\
70 "m" (__fcw) \
71 )
72
73#elif defined( __x86_64 )
74 #define CtxGet( ctx ) \
75 __asm__ volatile ( \
76 "movq %%rsp,%0\n"\
77 "movq %%rbp,%1\n"\
78 : "=rm" (ctx.SP),\
79 "=rm" (ctx.FP) \
80 )
81
82 #define __x87_store \
83 uint32_t __mxcr; \
84 uint16_t __fcw; \
85 __asm__ volatile ( \
86 "stmxcsr %0\n" \
87 "fnstcw %1\n" \
88 : "=m" (__mxcr),\
89 "=m" (__fcw) \
90 )
91
92 #define __x87_load \
93 __asm__ volatile ( \
94 "fldcw %1\n" \
95 "ldmxcsr %0\n" \
96 :: "m" (__mxcr),\
97 "m" (__fcw) \
98 )
99
100
101#elif defined( __ARM_ARCH )
102#define CtxGet( ctx ) __asm__ ( \
103 "mov %0,%%sp\n" \
104 "mov %1,%%r11\n" \
105 : "=rm" (ctx.SP), "=rm" (ctx.FP) )
106#else
107 #error unknown hardware architecture
108#endif
109
110//-----------------------------------------------------------------------------
111//Start and stop routine for the kernel, declared first to make sure they run first
112static void kernel_startup(void) __attribute__(( constructor( STARTUP_PRIORITY_KERNEL ) ));
113static void kernel_shutdown(void) __attribute__(( destructor ( STARTUP_PRIORITY_KERNEL ) ));
114
115//-----------------------------------------------------------------------------
116// Kernel storage
117KERNEL_STORAGE(cluster, mainCluster);
118KERNEL_STORAGE(processor, mainProcessor);
119KERNEL_STORAGE(thread_desc, mainThread);
120KERNEL_STORAGE(__stack_t, mainThreadCtx);
121
122cluster * mainCluster;
123processor * mainProcessor;
124thread_desc * mainThread;
125
126extern "C" {
127 struct { __dllist_t(cluster) list; __spinlock_t lock; } __cfa_dbg_global_clusters;
128}
129
130size_t __page_size = 0;
131
132//-----------------------------------------------------------------------------
133// Global state
134thread_local struct KernelThreadData kernelTLS __attribute__ ((tls_model ( "initial-exec" ))) = {
135 NULL, // cannot use 0p
136 NULL,
137 { NULL, 1, false, false },
138 6u //this should be seeded better but due to a bug calling rdtsc doesn't work
139};
140
141//-----------------------------------------------------------------------------
142// Struct to steal stack
143struct current_stack_info_t {
144 __stack_t * storage; // pointer to stack object
145 void * base; // base of stack
146 void * limit; // stack grows towards stack limit
147 void * context; // address of cfa_context_t
148};
149
150void ?{}( current_stack_info_t & this ) {
151 __stack_context_t ctx;
152 CtxGet( ctx );
153 this.base = ctx.FP;
154
155 rlimit r;
156 getrlimit( RLIMIT_STACK, &r);
157 size_t size = r.rlim_cur;
158
159 this.limit = (void *)(((intptr_t)this.base) - size);
160 this.context = &storage_mainThreadCtx;
161}
162
163//-----------------------------------------------------------------------------
164// Main thread construction
165
166void ?{}( coroutine_desc & this, current_stack_info_t * info) with( this ) {
167 stack.storage = info->storage;
168 with(*stack.storage) {
169 limit = info->limit;
170 base = info->base;
171 }
172 __attribute__((may_alias)) intptr_t * istorage = (intptr_t*) &stack.storage;
173 *istorage |= 0x1;
174 name = "Main Thread";
175 state = Start;
176 starter = 0p;
177 last = 0p;
178 cancellation = 0p;
179}
180
181void ?{}( thread_desc & this, current_stack_info_t * info) with( this ) {
182 state = Start;
183 self_cor{ info };
184 curr_cor = &self_cor;
185 curr_cluster = mainCluster;
186 self_mon.owner = &this;
187 self_mon.recursion = 1;
188 self_mon_p = &self_mon;
189 next = 0p;
190
191 node.next = 0p;
192 node.prev = 0p;
193 doregister(curr_cluster, this);
194
195 monitors{ &self_mon_p, 1, (fptr_t)0 };
196}
197
198//-----------------------------------------------------------------------------
199// Processor coroutine
200void ?{}(processorCtx_t & this) {
201
202}
203
204// Construct the processor context of non-main processors
205static void ?{}(processorCtx_t & this, processor * proc, current_stack_info_t * info) {
206 (this.__cor){ info };
207 this.proc = proc;
208}
209
210static void start(processor * this);
211void ?{}(processor & this, const char * name, cluster & cltr) with( this ) {
212 this.name = name;
213 this.cltr = &cltr;
214 terminated{ 0 };
215 do_terminate = false;
216 preemption_alarm = 0p;
217 pending_preemption = false;
218 runner.proc = &this;
219
220 idleLock{};
221
222 start( &this );
223}
224
225void ^?{}(processor & this) with( this ){
226 if( ! __atomic_load_n(&do_terminate, __ATOMIC_ACQUIRE) ) {
227 __cfaabi_dbg_print_safe("Kernel : core %p signaling termination\n", &this);
228
229 __atomic_store_n(&do_terminate, true, __ATOMIC_RELAXED);
230 wake( &this );
231
232 P( terminated );
233 verify( kernelTLS.this_processor != &this);
234 }
235
236 pthread_join( kernel_thread, 0p );
237 free( this.stack );
238}
239
240void ?{}(cluster & this, const char * name, Duration preemption_rate) with( this ) {
241 this.name = name;
242 this.preemption_rate = preemption_rate;
243 ready_queue{};
244 ready_queue_lock{};
245
246 procs{ __get };
247 idles{ __get };
248 threads{ __get };
249
250 doregister(this);
251}
252
253void ^?{}(cluster & this) {
254 unregister(this);
255}
256
257//=============================================================================================
258// Kernel Scheduling logic
259//=============================================================================================
260static void runThread(processor * this, thread_desc * dst);
261static void finishRunning(processor * this);
262static void halt(processor * this);
263
264//Main of the processor contexts
265void main(processorCtx_t & runner) {
266 // Because of a bug, we couldn't initialized the seed on construction
267 // Do it here
268 kernelTLS.rand_seed ^= rdtscl();
269
270 processor * this = runner.proc;
271 verify(this);
272
273 __cfaabi_dbg_print_safe("Kernel : core %p starting\n", this);
274
275 doregister(this->cltr, this);
276
277 {
278 // Setup preemption data
279 preemption_scope scope = { this };
280
281 __cfaabi_dbg_print_safe("Kernel : core %p started\n", this);
282
283 thread_desc * readyThread = 0p;
284 for( unsigned int spin_count = 0; ! __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST); spin_count++ ) {
285 readyThread = nextThread( this->cltr );
286
287 if(readyThread) {
288 verify( ! kernelTLS.preemption_state.enabled );
289
290 runThread(this, readyThread);
291
292 verify( ! kernelTLS.preemption_state.enabled );
293
294 //Some actions need to be taken from the kernel
295 finishRunning(this);
296
297 spin_count = 0;
298 } else {
299 // spin(this, &spin_count);
300 halt(this);
301 }
302 }
303
304 __cfaabi_dbg_print_safe("Kernel : core %p stopping\n", this);
305 }
306
307 unregister(this->cltr, this);
308
309 V( this->terminated );
310
311 __cfaabi_dbg_print_safe("Kernel : core %p terminated\n", this);
312}
313
314static int * __volatile_errno() __attribute__((noinline));
315static int * __volatile_errno() { asm(""); return &errno; }
316
317// KERNEL ONLY
318// runThread runs a thread by context switching
319// from the processor coroutine to the target thread
320static void runThread(processor * this, thread_desc * thrd_dst) {
321 coroutine_desc * proc_cor = get_coroutine(this->runner);
322
323 // Reset the terminating actions here
324 this->finish.action_code = No_Action;
325
326 // Update global state
327 kernelTLS.this_thread = thrd_dst;
328
329 // set state of processor coroutine to inactive and the thread to active
330 proc_cor->state = proc_cor->state == Halted ? Halted : Inactive;
331 thrd_dst->state = Active;
332
333 // set context switch to the thread that the processor is executing
334 verify( thrd_dst->context.SP );
335 CtxSwitch( &proc_cor->context, &thrd_dst->context );
336 // when CtxSwitch returns we are back in the processor coroutine
337
338 // set state of processor coroutine to active and the thread to inactive
339 thrd_dst->state = thrd_dst->state == Halted ? Halted : Inactive;
340 proc_cor->state = Active;
341}
342
343// KERNEL_ONLY
344static void returnToKernel() {
345 coroutine_desc * proc_cor = get_coroutine(kernelTLS.this_processor->runner);
346 thread_desc * thrd_src = kernelTLS.this_thread;
347
348 // set state of current coroutine to inactive
349 thrd_src->state = thrd_src->state == Halted ? Halted : Inactive;
350 proc_cor->state = Active;
351 int local_errno = *__volatile_errno();
352 #if defined( __i386 ) || defined( __x86_64 )
353 __x87_store;
354 #endif
355
356 // set new coroutine that the processor is executing
357 // and context switch to it
358 verify( proc_cor->context.SP );
359 CtxSwitch( &thrd_src->context, &proc_cor->context );
360
361 // set state of new coroutine to active
362 proc_cor->state = proc_cor->state == Halted ? Halted : Inactive;
363 thrd_src->state = Active;
364
365 #if defined( __i386 ) || defined( __x86_64 )
366 __x87_load;
367 #endif
368 *__volatile_errno() = local_errno;
369}
370
371// KERNEL_ONLY
372// Once a thread has finished running, some of
373// its final actions must be executed from the kernel
374static void finishRunning(processor * this) with( this->finish ) {
375 verify( ! kernelTLS.preemption_state.enabled );
376 choose( action_code ) {
377 case No_Action:
378 break;
379 case Release:
380 unlock( *lock );
381 case Schedule:
382 ScheduleThread( thrd );
383 case Release_Schedule:
384 unlock( *lock );
385 ScheduleThread( thrd );
386 case Release_Multi:
387 for(int i = 0; i < lock_count; i++) {
388 unlock( *locks[i] );
389 }
390 case Release_Multi_Schedule:
391 for(int i = 0; i < lock_count; i++) {
392 unlock( *locks[i] );
393 }
394 for(int i = 0; i < thrd_count; i++) {
395 ScheduleThread( thrds[i] );
396 }
397 case Callback:
398 callback();
399 default:
400 abort("KERNEL ERROR: Unexpected action to run after thread");
401 }
402}
403
404// KERNEL_ONLY
405// Context invoker for processors
406// This is the entry point for processors (kernel threads)
407// It effectively constructs a coroutine by stealing the pthread stack
408static void * CtxInvokeProcessor(void * arg) {
409 processor * proc = (processor *) arg;
410 kernelTLS.this_processor = proc;
411 kernelTLS.this_thread = 0p;
412 kernelTLS.preemption_state.[enabled, disable_count] = [false, 1];
413 // SKULLDUGGERY: We want to create a context for the processor coroutine
414 // which is needed for the 2-step context switch. However, there is no reason
415 // to waste the perfectly valid stack create by pthread.
416 current_stack_info_t info;
417 __stack_t ctx;
418 info.storage = &ctx;
419 (proc->runner){ proc, &info };
420
421 __cfaabi_dbg_print_safe("Coroutine : created stack %p\n", get_coroutine(proc->runner)->stack.storage);
422
423 //Set global state
424 kernelTLS.this_thread = 0p;
425
426 //We now have a proper context from which to schedule threads
427 __cfaabi_dbg_print_safe("Kernel : core %p created (%p, %p)\n", proc, &proc->runner, &ctx);
428
429 // SKULLDUGGERY: Since the coroutine doesn't have its own stack, we can't
430 // resume it to start it like it normally would, it will just context switch
431 // back to here. Instead directly call the main since we already are on the
432 // appropriate stack.
433 get_coroutine(proc->runner)->state = Active;
434 main( proc->runner );
435 get_coroutine(proc->runner)->state = Halted;
436
437 // Main routine of the core returned, the core is now fully terminated
438 __cfaabi_dbg_print_safe("Kernel : core %p main ended (%p)\n", proc, &proc->runner);
439
440 return 0p;
441}
442
443static void Abort( int ret, const char * func ) {
444 if ( ret ) { // pthread routines return errno values
445 abort( "%s : internal error, error(%d) %s.", func, ret, strerror( ret ) );
446 } // if
447} // Abort
448
449void * create_pthread( pthread_t * pthread, void * (*start)(void *), void * arg ) {
450 pthread_attr_t attr;
451
452 Abort( pthread_attr_init( &attr ), "pthread_attr_init" ); // initialize attribute
453
454 size_t stacksize;
455 // default stack size, normally defined by shell limit
456 Abort( pthread_attr_getstacksize( &attr, &stacksize ), "pthread_attr_getstacksize" );
457 assert( stacksize >= PTHREAD_STACK_MIN );
458
459#ifdef __CFA_DEBUG__
460 void * stack = memalign( __page_size, stacksize + __page_size );
461 // pthread has no mechanism to create the guard page in user supplied stack.
462 if ( mprotect( stack, __page_size, PROT_NONE ) == -1 ) {
463 abort( "mprotect : internal error, mprotect failure, error(%d) %s.", errno, strerror( errno ) );
464 } // if
465#else
466 void * stack = malloc( stacksize );
467#endif
468
469 Abort( pthread_attr_setstack( &attr, stack, stacksize ), "pthread_attr_setstack" );
470
471 Abort( pthread_create( pthread, &attr, start, arg ), "pthread_create" );
472 return stack;
473}
474
475static void start(processor * this) {
476 __cfaabi_dbg_print_safe("Kernel : Starting core %p\n", this);
477
478 this->stack = create_pthread( &this->kernel_thread, CtxInvokeProcessor, (void *)this );
479
480 __cfaabi_dbg_print_safe("Kernel : core %p started\n", this);
481}
482
483// KERNEL_ONLY
484void kernel_first_resume( processor * this ) {
485 thread_desc * src = mainThread;
486 coroutine_desc * dst = get_coroutine(this->runner);
487
488 verify( ! kernelTLS.preemption_state.enabled );
489
490 __stack_prepare( &dst->stack, 65000 );
491 CtxStart(&this->runner, CtxInvokeCoroutine);
492
493 verify( ! kernelTLS.preemption_state.enabled );
494
495 dst->last = &src->self_cor;
496 dst->starter = dst->starter ? dst->starter : &src->self_cor;
497
498 // set state of current coroutine to inactive
499 src->state = src->state == Halted ? Halted : Inactive;
500
501 // context switch to specified coroutine
502 verify( dst->context.SP );
503 CtxSwitch( &src->context, &dst->context );
504 // when CtxSwitch returns we are back in the src coroutine
505
506 // set state of new coroutine to active
507 src->state = Active;
508
509 verify( ! kernelTLS.preemption_state.enabled );
510}
511
512// KERNEL_ONLY
513void kernel_last_resume( processor * this ) {
514 coroutine_desc * src = &mainThread->self_cor;
515 coroutine_desc * dst = get_coroutine(this->runner);
516
517 verify( ! kernelTLS.preemption_state.enabled );
518 verify( dst->starter == src );
519 verify( dst->context.SP );
520
521 // context switch to the processor
522 CtxSwitch( &src->context, &dst->context );
523}
524
525//-----------------------------------------------------------------------------
526// Scheduler routines
527
528// KERNEL ONLY
529void ScheduleThread( thread_desc * thrd ) {
530 verify( thrd );
531 verify( thrd->state != Halted );
532
533 verify( ! kernelTLS.preemption_state.enabled );
534
535 verifyf( thrd->next == 0p, "Expected null got %p", thrd->next );
536
537 with( *thrd->curr_cluster ) {
538 lock ( ready_queue_lock __cfaabi_dbg_ctx2 );
539 bool was_empty = !(ready_queue != 0);
540 append( ready_queue, thrd );
541 unlock( ready_queue_lock );
542
543 if(was_empty) {
544 lock (proc_list_lock __cfaabi_dbg_ctx2);
545 if(idles) {
546 wake_fast(idles.head);
547 }
548 unlock (proc_list_lock);
549 }
550 else if( struct processor * idle = idles.head ) {
551 wake_fast(idle);
552 }
553
554 }
555
556 verify( ! kernelTLS.preemption_state.enabled );
557}
558
559// KERNEL ONLY
560thread_desc * nextThread(cluster * this) with( *this ) {
561 verify( ! kernelTLS.preemption_state.enabled );
562 lock( ready_queue_lock __cfaabi_dbg_ctx2 );
563 thread_desc * head = pop_head( ready_queue );
564 unlock( ready_queue_lock );
565 verify( ! kernelTLS.preemption_state.enabled );
566 return head;
567}
568
569void BlockInternal() {
570 disable_interrupts();
571 verify( ! kernelTLS.preemption_state.enabled );
572 returnToKernel();
573 verify( ! kernelTLS.preemption_state.enabled );
574 enable_interrupts( __cfaabi_dbg_ctx );
575}
576
577void BlockInternal( __spinlock_t * lock ) {
578 disable_interrupts();
579 with( *kernelTLS.this_processor ) {
580 finish.action_code = Release;
581 finish.lock = lock;
582 }
583
584 verify( ! kernelTLS.preemption_state.enabled );
585 returnToKernel();
586 verify( ! kernelTLS.preemption_state.enabled );
587
588 enable_interrupts( __cfaabi_dbg_ctx );
589}
590
591void BlockInternal( thread_desc * thrd ) {
592 disable_interrupts();
593 with( * kernelTLS.this_processor ) {
594 finish.action_code = Schedule;
595 finish.thrd = thrd;
596 }
597
598 verify( ! kernelTLS.preemption_state.enabled );
599 returnToKernel();
600 verify( ! kernelTLS.preemption_state.enabled );
601
602 enable_interrupts( __cfaabi_dbg_ctx );
603}
604
605void BlockInternal( __spinlock_t * lock, thread_desc * thrd ) {
606 assert(thrd);
607 disable_interrupts();
608 with( * kernelTLS.this_processor ) {
609 finish.action_code = Release_Schedule;
610 finish.lock = lock;
611 finish.thrd = thrd;
612 }
613
614 verify( ! kernelTLS.preemption_state.enabled );
615 returnToKernel();
616 verify( ! kernelTLS.preemption_state.enabled );
617
618 enable_interrupts( __cfaabi_dbg_ctx );
619}
620
621void BlockInternal(__spinlock_t * locks [], unsigned short count) {
622 disable_interrupts();
623 with( * kernelTLS.this_processor ) {
624 finish.action_code = Release_Multi;
625 finish.locks = locks;
626 finish.lock_count = count;
627 }
628
629 verify( ! kernelTLS.preemption_state.enabled );
630 returnToKernel();
631 verify( ! kernelTLS.preemption_state.enabled );
632
633 enable_interrupts( __cfaabi_dbg_ctx );
634}
635
636void BlockInternal(__spinlock_t * locks [], unsigned short lock_count, thread_desc * thrds [], unsigned short thrd_count) {
637 disable_interrupts();
638 with( *kernelTLS.this_processor ) {
639 finish.action_code = Release_Multi_Schedule;
640 finish.locks = locks;
641 finish.lock_count = lock_count;
642 finish.thrds = thrds;
643 finish.thrd_count = thrd_count;
644 }
645
646 verify( ! kernelTLS.preemption_state.enabled );
647 returnToKernel();
648 verify( ! kernelTLS.preemption_state.enabled );
649
650 enable_interrupts( __cfaabi_dbg_ctx );
651}
652
653void BlockInternal(__finish_callback_fptr_t callback) {
654 disable_interrupts();
655 with( *kernelTLS.this_processor ) {
656 finish.action_code = Callback;
657 finish.callback = callback;
658 }
659
660 verify( ! kernelTLS.preemption_state.enabled );
661 returnToKernel();
662 verify( ! kernelTLS.preemption_state.enabled );
663
664 enable_interrupts( __cfaabi_dbg_ctx );
665}
666
667// KERNEL ONLY
668void LeaveThread(__spinlock_t * lock, thread_desc * thrd) {
669 verify( ! kernelTLS.preemption_state.enabled );
670 with( * kernelTLS.this_processor ) {
671 finish.action_code = thrd ? Release_Schedule : Release;
672 finish.lock = lock;
673 finish.thrd = thrd;
674 }
675
676 returnToKernel();
677}
678
679//=============================================================================================
680// Kernel Setup logic
681//=============================================================================================
682//-----------------------------------------------------------------------------
683// Kernel boot procedures
684static void kernel_startup(void) {
685 verify( ! kernelTLS.preemption_state.enabled );
686 __cfaabi_dbg_print_safe("Kernel : Starting\n");
687
688 __page_size = sysconf( _SC_PAGESIZE );
689
690 __cfa_dbg_global_clusters.list{ __get };
691 __cfa_dbg_global_clusters.lock{};
692
693 // Initialize the main cluster
694 mainCluster = (cluster *)&storage_mainCluster;
695 (*mainCluster){"Main Cluster"};
696
697 __cfaabi_dbg_print_safe("Kernel : Main cluster ready\n");
698
699 // Start by initializing the main thread
700 // SKULLDUGGERY: the mainThread steals the process main thread
701 // which will then be scheduled by the mainProcessor normally
702 mainThread = (thread_desc *)&storage_mainThread;
703 current_stack_info_t info;
704 info.storage = (__stack_t*)&storage_mainThreadCtx;
705 (*mainThread){ &info };
706
707 __cfaabi_dbg_print_safe("Kernel : Main thread ready\n");
708
709
710
711 // Construct the processor context of the main processor
712 void ?{}(processorCtx_t & this, processor * proc) {
713 (this.__cor){ "Processor" };
714 this.__cor.starter = 0p;
715 this.proc = proc;
716 }
717
718 void ?{}(processor & this) with( this ) {
719 name = "Main Processor";
720 cltr = mainCluster;
721 terminated{ 0 };
722 do_terminate = false;
723 preemption_alarm = 0p;
724 pending_preemption = false;
725 kernel_thread = pthread_self();
726
727 runner{ &this };
728 __cfaabi_dbg_print_safe("Kernel : constructed main processor context %p\n", &runner);
729 }
730
731 // Initialize the main processor and the main processor ctx
732 // (the coroutine that contains the processing control flow)
733 mainProcessor = (processor *)&storage_mainProcessor;
734 (*mainProcessor){};
735
736 //initialize the global state variables
737 kernelTLS.this_processor = mainProcessor;
738 kernelTLS.this_thread = mainThread;
739
740 // Enable preemption
741 kernel_start_preemption();
742
743 // Add the main thread to the ready queue
744 // once resume is called on mainProcessor->runner the mainThread needs to be scheduled like any normal thread
745 ScheduleThread(mainThread);
746
747 // SKULLDUGGERY: Force a context switch to the main processor to set the main thread's context to the current UNIX
748 // context. Hence, the main thread does not begin through CtxInvokeThread, like all other threads. The trick here is that
749 // mainThread is on the ready queue when this call is made.
750 kernel_first_resume( kernelTLS.this_processor );
751
752
753
754 // THE SYSTEM IS NOW COMPLETELY RUNNING
755 __cfaabi_dbg_print_safe("Kernel : Started\n--------------------------------------------------\n\n");
756
757 verify( ! kernelTLS.preemption_state.enabled );
758 enable_interrupts( __cfaabi_dbg_ctx );
759 verify( TL_GET( preemption_state.enabled ) );
760}
761
762static void kernel_shutdown(void) {
763 __cfaabi_dbg_print_safe("\n--------------------------------------------------\nKernel : Shutting down\n");
764
765 verify( TL_GET( preemption_state.enabled ) );
766 disable_interrupts();
767 verify( ! kernelTLS.preemption_state.enabled );
768
769 // SKULLDUGGERY: Notify the mainProcessor it needs to terminates.
770 // When its coroutine terminates, it return control to the mainThread
771 // which is currently here
772 __atomic_store_n(&mainProcessor->do_terminate, true, __ATOMIC_RELEASE);
773 kernel_last_resume( kernelTLS.this_processor );
774 mainThread->self_cor.state = Halted;
775
776 // THE SYSTEM IS NOW COMPLETELY STOPPED
777
778 // Disable preemption
779 kernel_stop_preemption();
780
781 // Destroy the main processor and its context in reverse order of construction
782 // These were manually constructed so we need manually destroy them
783 ^(mainProcessor->runner){};
784 ^(mainProcessor){};
785
786 // Final step, destroy the main thread since it is no longer needed
787 // Since we provided a stack to this taxk it will not destroy anything
788 ^(mainThread){};
789
790 ^(__cfa_dbg_global_clusters.list){};
791 ^(__cfa_dbg_global_clusters.lock){};
792
793 __cfaabi_dbg_print_safe("Kernel : Shutdown complete\n");
794}
795
796//=============================================================================================
797// Kernel Quiescing
798//=============================================================================================
799static void halt(processor * this) with( *this ) {
800 // verify( ! __atomic_load_n(&do_terminate, __ATOMIC_SEQ_CST) );
801
802 with( *cltr ) {
803 lock (proc_list_lock __cfaabi_dbg_ctx2);
804 remove (procs, *this);
805 push_front(idles, *this);
806 unlock (proc_list_lock);
807 }
808
809 __cfaabi_dbg_print_safe("Kernel : Processor %p ready to sleep\n", this);
810
811 wait( idleLock );
812
813 __cfaabi_dbg_print_safe("Kernel : Processor %p woke up and ready to run\n", this);
814
815 with( *cltr ) {
816 lock (proc_list_lock __cfaabi_dbg_ctx2);
817 remove (idles, *this);
818 push_front(procs, *this);
819 unlock (proc_list_lock);
820 }
821}
822
823//=============================================================================================
824// Unexpected Terminating logic
825//=============================================================================================
826static __spinlock_t kernel_abort_lock;
827static bool kernel_abort_called = false;
828
829void * kernel_abort(void) __attribute__ ((__nothrow__)) {
830 // abort cannot be recursively entered by the same or different processors because all signal handlers return when
831 // the globalAbort flag is true.
832 lock( kernel_abort_lock __cfaabi_dbg_ctx2 );
833
834 // first task to abort ?
835 if ( kernel_abort_called ) { // not first task to abort ?
836 unlock( kernel_abort_lock );
837
838 sigset_t mask;
839 sigemptyset( &mask );
840 sigaddset( &mask, SIGALRM ); // block SIGALRM signals
841 sigsuspend( &mask ); // block the processor to prevent further damage during abort
842 _exit( EXIT_FAILURE ); // if processor unblocks before it is killed, terminate it
843 }
844 else {
845 kernel_abort_called = true;
846 unlock( kernel_abort_lock );
847 }
848
849 return kernelTLS.this_thread;
850}
851
852void kernel_abort_msg( void * kernel_data, char * abort_text, int abort_text_size ) {
853 thread_desc * thrd = kernel_data;
854
855 if(thrd) {
856 int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
857 __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
858
859 if ( &thrd->self_cor != thrd->curr_cor ) {
860 len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
861 __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
862 }
863 else {
864 __cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
865 }
866 }
867 else {
868 int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
869 __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
870 }
871}
872
873int kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
874 return get_coroutine(kernelTLS.this_thread) == get_coroutine(mainThread) ? 4 : 2;
875}
876
877static __spinlock_t kernel_debug_lock;
878
879extern "C" {
880 void __cfaabi_bits_acquire() {
881 lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
882 }
883
884 void __cfaabi_bits_release() {
885 unlock( kernel_debug_lock );
886 }
887}
888
889//=============================================================================================
890// Kernel Utilities
891//=============================================================================================
892//-----------------------------------------------------------------------------
893// Locks
894void ?{}( semaphore & this, int count = 1 ) {
895 (this.lock){};
896 this.count = count;
897 (this.waiting){};
898}
899void ^?{}(semaphore & this) {}
900
901void P(semaphore & this) with( this ){
902 lock( lock __cfaabi_dbg_ctx2 );
903 count -= 1;
904 if ( count < 0 ) {
905 // queue current task
906 append( waiting, kernelTLS.this_thread );
907
908 // atomically release spin lock and block
909 BlockInternal( &lock );
910 }
911 else {
912 unlock( lock );
913 }
914}
915
916void V(semaphore & this) with( this ) {
917 thread_desc * thrd = 0p;
918 lock( lock __cfaabi_dbg_ctx2 );
919 count += 1;
920 if ( count <= 0 ) {
921 // remove task at head of waiting list
922 thrd = pop_head( waiting );
923 }
924
925 unlock( lock );
926
927 // make new owner
928 WakeThread( thrd );
929}
930
931//-----------------------------------------------------------------------------
932// Global Queues
933void doregister( cluster & cltr ) {
934 lock ( __cfa_dbg_global_clusters.lock __cfaabi_dbg_ctx2);
935 push_front( __cfa_dbg_global_clusters.list, cltr );
936 unlock ( __cfa_dbg_global_clusters.lock );
937}
938
939void unregister( cluster & cltr ) {
940 lock ( __cfa_dbg_global_clusters.lock __cfaabi_dbg_ctx2);
941 remove( __cfa_dbg_global_clusters.list, cltr );
942 unlock( __cfa_dbg_global_clusters.lock );
943}
944
945void doregister( cluster * cltr, thread_desc & thrd ) {
946 lock (cltr->thread_list_lock __cfaabi_dbg_ctx2);
947 cltr->nthreads += 1;
948 push_front(cltr->threads, thrd);
949 unlock (cltr->thread_list_lock);
950}
951
952void unregister( cluster * cltr, thread_desc & thrd ) {
953 lock (cltr->thread_list_lock __cfaabi_dbg_ctx2);
954 remove(cltr->threads, thrd );
955 cltr->nthreads -= 1;
956 unlock(cltr->thread_list_lock);
957}
958
959void doregister( cluster * cltr, processor * proc ) {
960 lock (cltr->proc_list_lock __cfaabi_dbg_ctx2);
961 cltr->nprocessors += 1;
962 push_front(cltr->procs, *proc);
963 unlock (cltr->proc_list_lock);
964}
965
966void unregister( cluster * cltr, processor * proc ) {
967 lock (cltr->proc_list_lock __cfaabi_dbg_ctx2);
968 remove(cltr->procs, *proc );
969 cltr->nprocessors -= 1;
970 unlock(cltr->proc_list_lock);
971}
972
973//-----------------------------------------------------------------------------
974// Debug
975__cfaabi_dbg_debug_do(
976 extern "C" {
977 void __cfaabi_dbg_record(__spinlock_t & this, const char * prev_name) {
978 this.prev_name = prev_name;
979 this.prev_thrd = kernelTLS.this_thread;
980 }
981 }
982)
983
984//-----------------------------------------------------------------------------
985// Debug
986bool threading_enabled(void) {
987 return true;
988}
989// Local Variables: //
990// mode: c //
991// tab-width: 4 //
992// End: //
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