source: libcfa/src/concurrency/kernel.cfa@ 596fc4ad

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 596fc4ad was 09d4b22, checked in by Peter A. Buhr <pabuhr@…>, 6 years ago

move stack for preemptive pthread from TLS to static variable
  • 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 : Thu Dec 5 16:25:52 2019
13// Update Count : 52
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 { 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 void * stack;
460 __cfaabi_dbg_debug_do(
461 stack = memalign( __page_size, stacksize + __page_size );
462 // pthread has no mechanism to create the guard page in user supplied stack.
463 if ( mprotect( stack, __page_size, PROT_NONE ) == -1 ) {
464 abort( "mprotect : internal error, mprotect failure, error(%d) %s.", errno, strerror( errno ) );
465 } // if
466 );
467 __cfaabi_dbg_no_debug_do(
468 stack = malloc( stacksize );
469 );
470
471 Abort( pthread_attr_setstack( &attr, stack, stacksize ), "pthread_attr_setstack" );
472
473 Abort( pthread_create( pthread, &attr, start, arg ), "pthread_create" );
474 return stack;
475}
476
477static void start(processor * this) {
478 __cfaabi_dbg_print_safe("Kernel : Starting core %p\n", this);
479
480 this->stack = create_pthread( &this->kernel_thread, CtxInvokeProcessor, (void *)this );
481
482 __cfaabi_dbg_print_safe("Kernel : core %p started\n", this);
483}
484
485// KERNEL_ONLY
486void kernel_first_resume( processor * this ) {
487 thread_desc * src = mainThread;
488 coroutine_desc * dst = get_coroutine(this->runner);
489
490 verify( ! kernelTLS.preemption_state.enabled );
491
492 __stack_prepare( &dst->stack, 65000 );
493 CtxStart(&this->runner, CtxInvokeCoroutine);
494
495 verify( ! kernelTLS.preemption_state.enabled );
496
497 dst->last = &src->self_cor;
498 dst->starter = dst->starter ? dst->starter : &src->self_cor;
499
500 // set state of current coroutine to inactive
501 src->state = src->state == Halted ? Halted : Inactive;
502
503 // context switch to specified coroutine
504 verify( dst->context.SP );
505 CtxSwitch( &src->context, &dst->context );
506 // when CtxSwitch returns we are back in the src coroutine
507
508 // set state of new coroutine to active
509 src->state = Active;
510
511 verify( ! kernelTLS.preemption_state.enabled );
512}
513
514// KERNEL_ONLY
515void kernel_last_resume( processor * this ) {
516 coroutine_desc * src = &mainThread->self_cor;
517 coroutine_desc * dst = get_coroutine(this->runner);
518
519 verify( ! kernelTLS.preemption_state.enabled );
520 verify( dst->starter == src );
521 verify( dst->context.SP );
522
523 // context switch to the processor
524 CtxSwitch( &src->context, &dst->context );
525}
526
527//-----------------------------------------------------------------------------
528// Scheduler routines
529
530// KERNEL ONLY
531void ScheduleThread( thread_desc * thrd ) {
532 verify( thrd );
533 verify( thrd->state != Halted );
534
535 verify( ! kernelTLS.preemption_state.enabled );
536
537 verifyf( thrd->next == 0p, "Expected null got %p", thrd->next );
538
539 with( *thrd->curr_cluster ) {
540 lock ( ready_queue_lock __cfaabi_dbg_ctx2 );
541 bool was_empty = !(ready_queue != 0);
542 append( ready_queue, thrd );
543 unlock( ready_queue_lock );
544
545 if(was_empty) {
546 lock (proc_list_lock __cfaabi_dbg_ctx2);
547 if(idles) {
548 wake_fast(idles.head);
549 }
550 unlock (proc_list_lock);
551 }
552 else if( struct processor * idle = idles.head ) {
553 wake_fast(idle);
554 }
555
556 }
557
558 verify( ! kernelTLS.preemption_state.enabled );
559}
560
561// KERNEL ONLY
562thread_desc * nextThread(cluster * this) with( *this ) {
563 verify( ! kernelTLS.preemption_state.enabled );
564 lock( ready_queue_lock __cfaabi_dbg_ctx2 );
565 thread_desc * head = pop_head( ready_queue );
566 unlock( ready_queue_lock );
567 verify( ! kernelTLS.preemption_state.enabled );
568 return head;
569}
570
571void BlockInternal() {
572 disable_interrupts();
573 verify( ! kernelTLS.preemption_state.enabled );
574 returnToKernel();
575 verify( ! kernelTLS.preemption_state.enabled );
576 enable_interrupts( __cfaabi_dbg_ctx );
577}
578
579void BlockInternal( __spinlock_t * lock ) {
580 disable_interrupts();
581 with( *kernelTLS.this_processor ) {
582 finish.action_code = Release;
583 finish.lock = lock;
584 }
585
586 verify( ! kernelTLS.preemption_state.enabled );
587 returnToKernel();
588 verify( ! kernelTLS.preemption_state.enabled );
589
590 enable_interrupts( __cfaabi_dbg_ctx );
591}
592
593void BlockInternal( thread_desc * thrd ) {
594 disable_interrupts();
595 with( * kernelTLS.this_processor ) {
596 finish.action_code = Schedule;
597 finish.thrd = thrd;
598 }
599
600 verify( ! kernelTLS.preemption_state.enabled );
601 returnToKernel();
602 verify( ! kernelTLS.preemption_state.enabled );
603
604 enable_interrupts( __cfaabi_dbg_ctx );
605}
606
607void BlockInternal( __spinlock_t * lock, thread_desc * thrd ) {
608 assert(thrd);
609 disable_interrupts();
610 with( * kernelTLS.this_processor ) {
611 finish.action_code = Release_Schedule;
612 finish.lock = lock;
613 finish.thrd = thrd;
614 }
615
616 verify( ! kernelTLS.preemption_state.enabled );
617 returnToKernel();
618 verify( ! kernelTLS.preemption_state.enabled );
619
620 enable_interrupts( __cfaabi_dbg_ctx );
621}
622
623void BlockInternal(__spinlock_t * locks [], unsigned short count) {
624 disable_interrupts();
625 with( * kernelTLS.this_processor ) {
626 finish.action_code = Release_Multi;
627 finish.locks = locks;
628 finish.lock_count = count;
629 }
630
631 verify( ! kernelTLS.preemption_state.enabled );
632 returnToKernel();
633 verify( ! kernelTLS.preemption_state.enabled );
634
635 enable_interrupts( __cfaabi_dbg_ctx );
636}
637
638void BlockInternal(__spinlock_t * locks [], unsigned short lock_count, thread_desc * thrds [], unsigned short thrd_count) {
639 disable_interrupts();
640 with( *kernelTLS.this_processor ) {
641 finish.action_code = Release_Multi_Schedule;
642 finish.locks = locks;
643 finish.lock_count = lock_count;
644 finish.thrds = thrds;
645 finish.thrd_count = thrd_count;
646 }
647
648 verify( ! kernelTLS.preemption_state.enabled );
649 returnToKernel();
650 verify( ! kernelTLS.preemption_state.enabled );
651
652 enable_interrupts( __cfaabi_dbg_ctx );
653}
654
655void BlockInternal(__finish_callback_fptr_t callback) {
656 disable_interrupts();
657 with( *kernelTLS.this_processor ) {
658 finish.action_code = Callback;
659 finish.callback = callback;
660 }
661
662 verify( ! kernelTLS.preemption_state.enabled );
663 returnToKernel();
664 verify( ! kernelTLS.preemption_state.enabled );
665
666 enable_interrupts( __cfaabi_dbg_ctx );
667}
668
669// KERNEL ONLY
670void LeaveThread(__spinlock_t * lock, thread_desc * thrd) {
671 verify( ! kernelTLS.preemption_state.enabled );
672 with( * kernelTLS.this_processor ) {
673 finish.action_code = thrd ? Release_Schedule : Release;
674 finish.lock = lock;
675 finish.thrd = thrd;
676 }
677
678 returnToKernel();
679}
680
681//=============================================================================================
682// Kernel Setup logic
683//=============================================================================================
684//-----------------------------------------------------------------------------
685// Kernel boot procedures
686static void kernel_startup(void) {
687 verify( ! kernelTLS.preemption_state.enabled );
688 __cfaabi_dbg_print_safe("Kernel : Starting\n");
689
690 __page_size = sysconf( _SC_PAGESIZE );
691
692 __cfa_dbg_global_clusters.list{ __get };
693 __cfa_dbg_global_clusters.lock{};
694
695 // Initialize the main cluster
696 mainCluster = (cluster *)&storage_mainCluster;
697 (*mainCluster){"Main Cluster"};
698
699 __cfaabi_dbg_print_safe("Kernel : Main cluster ready\n");
700
701 // Start by initializing the main thread
702 // SKULLDUGGERY: the mainThread steals the process main thread
703 // which will then be scheduled by the mainProcessor normally
704 mainThread = (thread_desc *)&storage_mainThread;
705 current_stack_info_t info;
706 info.storage = (__stack_t*)&storage_mainThreadCtx;
707 (*mainThread){ &info };
708
709 __cfaabi_dbg_print_safe("Kernel : Main thread ready\n");
710
711
712
713 // Construct the processor context of the main processor
714 void ?{}(processorCtx_t & this, processor * proc) {
715 (this.__cor){ "Processor" };
716 this.__cor.starter = 0p;
717 this.proc = proc;
718 }
719
720 void ?{}(processor & this) with( this ) {
721 name = "Main Processor";
722 cltr = mainCluster;
723 terminated{ 0 };
724 do_terminate = false;
725 preemption_alarm = 0p;
726 pending_preemption = false;
727 kernel_thread = pthread_self();
728
729 runner{ &this };
730 __cfaabi_dbg_print_safe("Kernel : constructed main processor context %p\n", &runner);
731 }
732
733 // Initialize the main processor and the main processor ctx
734 // (the coroutine that contains the processing control flow)
735 mainProcessor = (processor *)&storage_mainProcessor;
736 (*mainProcessor){};
737
738 //initialize the global state variables
739 kernelTLS.this_processor = mainProcessor;
740 kernelTLS.this_thread = mainThread;
741
742 // Enable preemption
743 kernel_start_preemption();
744
745 // Add the main thread to the ready queue
746 // once resume is called on mainProcessor->runner the mainThread needs to be scheduled like any normal thread
747 ScheduleThread(mainThread);
748
749 // SKULLDUGGERY: Force a context switch to the main processor to set the main thread's context to the current UNIX
750 // context. Hence, the main thread does not begin through CtxInvokeThread, like all other threads. The trick here is that
751 // mainThread is on the ready queue when this call is made.
752 kernel_first_resume( kernelTLS.this_processor );
753
754
755
756 // THE SYSTEM IS NOW COMPLETELY RUNNING
757 __cfaabi_dbg_print_safe("Kernel : Started\n--------------------------------------------------\n\n");
758
759 verify( ! kernelTLS.preemption_state.enabled );
760 enable_interrupts( __cfaabi_dbg_ctx );
761 verify( TL_GET( preemption_state.enabled ) );
762}
763
764static void kernel_shutdown(void) {
765 __cfaabi_dbg_print_safe("\n--------------------------------------------------\nKernel : Shutting down\n");
766
767 verify( TL_GET( preemption_state.enabled ) );
768 disable_interrupts();
769 verify( ! kernelTLS.preemption_state.enabled );
770
771 // SKULLDUGGERY: Notify the mainProcessor it needs to terminates.
772 // When its coroutine terminates, it return control to the mainThread
773 // which is currently here
774 __atomic_store_n(&mainProcessor->do_terminate, true, __ATOMIC_RELEASE);
775 kernel_last_resume( kernelTLS.this_processor );
776 mainThread->self_cor.state = Halted;
777
778 // THE SYSTEM IS NOW COMPLETELY STOPPED
779
780 // Disable preemption
781 kernel_stop_preemption();
782
783 // Destroy the main processor and its context in reverse order of construction
784 // These were manually constructed so we need manually destroy them
785 ^(mainProcessor->runner){};
786 ^(mainProcessor){};
787
788 // Final step, destroy the main thread since it is no longer needed
789 // Since we provided a stack to this taxk it will not destroy anything
790 ^(mainThread){};
791
792 ^(__cfa_dbg_global_clusters.list){};
793 ^(__cfa_dbg_global_clusters.lock){};
794
795 __cfaabi_dbg_print_safe("Kernel : Shutdown complete\n");
796}
797
798//=============================================================================================
799// Kernel Quiescing
800//=============================================================================================
801static void halt(processor * this) with( *this ) {
802 // verify( ! __atomic_load_n(&do_terminate, __ATOMIC_SEQ_CST) );
803
804 with( *cltr ) {
805 lock (proc_list_lock __cfaabi_dbg_ctx2);
806 remove (procs, *this);
807 push_front(idles, *this);
808 unlock (proc_list_lock);
809 }
810
811 __cfaabi_dbg_print_safe("Kernel : Processor %p ready to sleep\n", this);
812
813 wait( idleLock );
814
815 __cfaabi_dbg_print_safe("Kernel : Processor %p woke up and ready to run\n", this);
816
817 with( *cltr ) {
818 lock (proc_list_lock __cfaabi_dbg_ctx2);
819 remove (idles, *this);
820 push_front(procs, *this);
821 unlock (proc_list_lock);
822 }
823}
824
825//=============================================================================================
826// Unexpected Terminating logic
827//=============================================================================================
828static __spinlock_t kernel_abort_lock;
829static bool kernel_abort_called = false;
830
831void * kernel_abort(void) __attribute__ ((__nothrow__)) {
832 // abort cannot be recursively entered by the same or different processors because all signal handlers return when
833 // the globalAbort flag is true.
834 lock( kernel_abort_lock __cfaabi_dbg_ctx2 );
835
836 // first task to abort ?
837 if ( kernel_abort_called ) { // not first task to abort ?
838 unlock( kernel_abort_lock );
839
840 sigset_t mask;
841 sigemptyset( &mask );
842 sigaddset( &mask, SIGALRM ); // block SIGALRM signals
843 sigsuspend( &mask ); // block the processor to prevent further damage during abort
844 _exit( EXIT_FAILURE ); // if processor unblocks before it is killed, terminate it
845 }
846 else {
847 kernel_abort_called = true;
848 unlock( kernel_abort_lock );
849 }
850
851 return kernelTLS.this_thread;
852}
853
854void kernel_abort_msg( void * kernel_data, char * abort_text, int abort_text_size ) {
855 thread_desc * thrd = kernel_data;
856
857 if(thrd) {
858 int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
859 __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
860
861 if ( &thrd->self_cor != thrd->curr_cor ) {
862 len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
863 __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
864 }
865 else {
866 __cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
867 }
868 }
869 else {
870 int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
871 __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
872 }
873}
874
875int kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
876 return get_coroutine(kernelTLS.this_thread) == get_coroutine(mainThread) ? 4 : 2;
877}
878
879static __spinlock_t kernel_debug_lock;
880
881extern "C" {
882 void __cfaabi_bits_acquire() {
883 lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
884 }
885
886 void __cfaabi_bits_release() {
887 unlock( kernel_debug_lock );
888 }
889}
890
891//=============================================================================================
892// Kernel Utilities
893//=============================================================================================
894//-----------------------------------------------------------------------------
895// Locks
896void ?{}( semaphore & this, int count = 1 ) {
897 (this.lock){};
898 this.count = count;
899 (this.waiting){};
900}
901void ^?{}(semaphore & this) {}
902
903void P(semaphore & this) with( this ){
904 lock( lock __cfaabi_dbg_ctx2 );
905 count -= 1;
906 if ( count < 0 ) {
907 // queue current task
908 append( waiting, kernelTLS.this_thread );
909
910 // atomically release spin lock and block
911 BlockInternal( &lock );
912 }
913 else {
914 unlock( lock );
915 }
916}
917
918void V(semaphore & this) with( this ) {
919 thread_desc * thrd = 0p;
920 lock( lock __cfaabi_dbg_ctx2 );
921 count += 1;
922 if ( count <= 0 ) {
923 // remove task at head of waiting list
924 thrd = pop_head( waiting );
925 }
926
927 unlock( lock );
928
929 // make new owner
930 WakeThread( thrd );
931}
932
933//-----------------------------------------------------------------------------
934// Global Queues
935void doregister( cluster & cltr ) {
936 lock ( __cfa_dbg_global_clusters.lock __cfaabi_dbg_ctx2);
937 push_front( __cfa_dbg_global_clusters.list, cltr );
938 unlock ( __cfa_dbg_global_clusters.lock );
939}
940
941void unregister( cluster & cltr ) {
942 lock ( __cfa_dbg_global_clusters.lock __cfaabi_dbg_ctx2);
943 remove( __cfa_dbg_global_clusters.list, cltr );
944 unlock( __cfa_dbg_global_clusters.lock );
945}
946
947void doregister( cluster * cltr, thread_desc & thrd ) {
948 lock (cltr->thread_list_lock __cfaabi_dbg_ctx2);
949 cltr->nthreads += 1;
950 push_front(cltr->threads, thrd);
951 unlock (cltr->thread_list_lock);
952}
953
954void unregister( cluster * cltr, thread_desc & thrd ) {
955 lock (cltr->thread_list_lock __cfaabi_dbg_ctx2);
956 remove(cltr->threads, thrd );
957 cltr->nthreads -= 1;
958 unlock(cltr->thread_list_lock);
959}
960
961void doregister( cluster * cltr, processor * proc ) {
962 lock (cltr->proc_list_lock __cfaabi_dbg_ctx2);
963 cltr->nprocessors += 1;
964 push_front(cltr->procs, *proc);
965 unlock (cltr->proc_list_lock);
966}
967
968void unregister( cluster * cltr, processor * proc ) {
969 lock (cltr->proc_list_lock __cfaabi_dbg_ctx2);
970 remove(cltr->procs, *proc );
971 cltr->nprocessors -= 1;
972 unlock(cltr->proc_list_lock);
973}
974
975//-----------------------------------------------------------------------------
976// Debug
977__cfaabi_dbg_debug_do(
978 extern "C" {
979 void __cfaabi_dbg_record(__spinlock_t & this, const char * prev_name) {
980 this.prev_name = prev_name;
981 this.prev_thrd = kernelTLS.this_thread;
982 }
983 }
984)
985
986//-----------------------------------------------------------------------------
987// Debug
988bool threading_enabled(void) {
989 return true;
990}
991// Local Variables: //
992// mode: c //
993// tab-width: 4 //
994// End: //
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