source: libcfa/src/concurrency/kernel.cfa@ e262b5e

ADT arm-eh ast-experimental enum forall-pointer-decay jacob/cs343-translation new-ast new-ast-unique-expr pthread-emulation qualifiedEnum
Last change on this file since e262b5e was 28d73c1, checked in by Thierry Delisle <tdelisle@…>, 5 years ago

Moved processor registration to constructor
  • Property mode set to 100644
File size: 37.7 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 Jul 9 06:22:54 2020
13// Update Count : 66
14//
15
16#define __cforall_thread__
17// #define __CFA_DEBUG_PRINT_RUNTIME_CORE__
18
19//C Includes
20#include <stddef.h>
21#include <errno.h>
22#include <string.h>
23#include <stdio.h>
24#include <fenv.h>
25#include <signal.h>
26#include <unistd.h>
27#include <limits.h> // PTHREAD_STACK_MIN
28#include <sys/mman.h> // mprotect
29extern "C" {
30#include <sys/resource.h>
31}
32
33//CFA Includes
34#include "time.hfa"
35#include "kernel_private.hfa"
36#include "preemption.hfa"
37#include "startup.hfa"
38
39//Private includes
40#define __CFA_INVOKE_PRIVATE__
41#include "invoke.h"
42
43
44//-----------------------------------------------------------------------------
45// Some assembly required
46#if defined( __i386 )
47 #define CtxGet( ctx ) \
48 __asm__ volatile ( \
49 "movl %%esp,%0\n"\
50 "movl %%ebp,%1\n"\
51 : "=rm" (ctx.SP),\
52 "=rm" (ctx.FP) \
53 )
54
55 // mxcr : SSE Status and Control bits (control bits are preserved across function calls)
56 // fcw : X87 FPU control word (preserved across function calls)
57 #define __x87_store \
58 uint32_t __mxcr; \
59 uint16_t __fcw; \
60 __asm__ volatile ( \
61 "stmxcsr %0\n" \
62 "fnstcw %1\n" \
63 : "=m" (__mxcr),\
64 "=m" (__fcw) \
65 )
66
67 #define __x87_load \
68 __asm__ volatile ( \
69 "fldcw %1\n" \
70 "ldmxcsr %0\n" \
71 ::"m" (__mxcr),\
72 "m" (__fcw) \
73 )
74
75#elif defined( __x86_64 )
76 #define CtxGet( ctx ) \
77 __asm__ volatile ( \
78 "movq %%rsp,%0\n"\
79 "movq %%rbp,%1\n"\
80 : "=rm" (ctx.SP),\
81 "=rm" (ctx.FP) \
82 )
83
84 #define __x87_store \
85 uint32_t __mxcr; \
86 uint16_t __fcw; \
87 __asm__ volatile ( \
88 "stmxcsr %0\n" \
89 "fnstcw %1\n" \
90 : "=m" (__mxcr),\
91 "=m" (__fcw) \
92 )
93
94 #define __x87_load \
95 __asm__ volatile ( \
96 "fldcw %1\n" \
97 "ldmxcsr %0\n" \
98 :: "m" (__mxcr),\
99 "m" (__fcw) \
100 )
101
102
103#elif defined( __ARM_ARCH )
104#define CtxGet( ctx ) __asm__ ( \
105 "mov %0,%%sp\n" \
106 "mov %1,%%r11\n" \
107 : "=rm" (ctx.SP), "=rm" (ctx.FP) )
108#else
109 #error unknown hardware architecture
110#endif
111
112//-----------------------------------------------------------------------------
113//Start and stop routine for the kernel, declared first to make sure they run first
114static void __kernel_startup (void) __attribute__(( constructor( STARTUP_PRIORITY_KERNEL ) ));
115static void __kernel_shutdown(void) __attribute__(( destructor ( STARTUP_PRIORITY_KERNEL ) ));
116
117//-----------------------------------------------------------------------------
118// Kernel Scheduling logic
119static $thread * __next_thread(cluster * this);
120static bool __has_next_thread(cluster * this);
121static void __run_thread(processor * this, $thread * dst);
122static bool __wake_proc(processor *);
123static bool __wake_one(struct __processor_id_t * id, cluster * cltr);
124static void __halt(processor * this);
125
126//-----------------------------------------------------------------------------
127// Kernel storage
128KERNEL_STORAGE(cluster, mainCluster);
129KERNEL_STORAGE(processor, mainProcessor);
130KERNEL_STORAGE($thread, mainThread);
131KERNEL_STORAGE(__stack_t, mainThreadCtx);
132KERNEL_STORAGE(__scheduler_RWLock_t, __scheduler_lock);
133#if !defined(__CFA_NO_STATISTICS__)
134KERNEL_STORAGE(__stats_t, mainProcStats);
135#endif
136
137cluster * mainCluster;
138processor * mainProcessor;
139$thread * mainThread;
140__scheduler_RWLock_t * __scheduler_lock;
141
142extern "C" {
143 struct { __dllist_t(cluster) list; __spinlock_t lock; } __cfa_dbg_global_clusters;
144}
145
146size_t __page_size = 0;
147
148//-----------------------------------------------------------------------------
149// Global state
150thread_local struct KernelThreadData kernelTLS __attribute__ ((tls_model ( "initial-exec" ))) @= {
151 NULL, // cannot use 0p
152 NULL,
153 NULL,
154 { 1, false, false },
155};
156
157//-----------------------------------------------------------------------------
158// Struct to steal stack
159struct current_stack_info_t {
160 __stack_t * storage; // pointer to stack object
161 void * base; // base of stack
162 void * limit; // stack grows towards stack limit
163 void * context; // address of cfa_context_t
164};
165
166void ?{}( current_stack_info_t & this ) {
167 __stack_context_t ctx;
168 CtxGet( ctx );
169 this.base = ctx.FP;
170
171 rlimit r;
172 getrlimit( RLIMIT_STACK, &r);
173 size_t size = r.rlim_cur;
174
175 this.limit = (void *)(((intptr_t)this.base) - size);
176 this.context = &storage_mainThreadCtx;
177}
178
179//-----------------------------------------------------------------------------
180// Main thread construction
181
182void ?{}( $coroutine & this, current_stack_info_t * info) with( this ) {
183 stack.storage = info->storage;
184 with(*stack.storage) {
185 limit = info->limit;
186 base = info->base;
187 }
188 __attribute__((may_alias)) intptr_t * istorage = (intptr_t*) &stack.storage;
189 *istorage |= 0x1;
190 name = "Main Thread";
191 state = Start;
192 starter = 0p;
193 last = 0p;
194 cancellation = 0p;
195}
196
197void ?{}( $thread & this, current_stack_info_t * info) with( this ) {
198 ticket = 1;
199 state = Start;
200 self_cor{ info };
201 curr_cor = &self_cor;
202 curr_cluster = mainCluster;
203 self_mon.owner = &this;
204 self_mon.recursion = 1;
205 self_mon_p = &self_mon;
206 link.next = 0p;
207 link.prev = 0p;
208
209 node.next = 0p;
210 node.prev = 0p;
211 doregister(curr_cluster, this);
212
213 monitors{ &self_mon_p, 1, (fptr_t)0 };
214}
215
216//-----------------------------------------------------------------------------
217// Processor coroutine
218void ?{}(processorCtx_t & this) {
219
220}
221
222// Construct the processor context of non-main processors
223static void ?{}(processorCtx_t & this, processor * proc, current_stack_info_t * info) {
224 (this.__cor){ info };
225 this.proc = proc;
226}
227
228static void * __invoke_processor(void * arg);
229
230static init(processor & this, const char name[], cluster & _cltr) with( this ) {
231 this.name = name;
232 this.cltr = &_cltr;
233 id = -1u;
234 destroyer = 0p;
235 do_terminate = false;
236 preemption_alarm = 0p;
237 pending_preemption = false;
238
239 #if !defined(__CFA_NO_STATISTICS__)
240 print_stats = 0;
241 print_halts = false;
242 #endif
243
244 __atomic_fetch_add( &cltr->nprocessors, 1u, __ATOMIC_SEQ_CST );
245
246 id = doregister((__processor_id_t*)&this);
247
248 // Lock the RWlock so no-one pushes/pops while we are changing the queue
249 uint_fast32_t last_size = ready_mutate_lock();
250
251 // Adjust the ready queue size
252 ready_queue_grow( cltr );
253
254 // Unlock the RWlock
255 ready_mutate_unlock( last_size );
256
257 __cfadbg_print_safe(runtime_core, "Kernel : core %p created\n", &this);
258}
259
260// Not a ctor, it just preps the destruction but should not destroy members
261void deinit(processor & this) {
262 // Lock the RWlock so no-one pushes/pops while we are changing the queue
263 uint_fast32_t last_size = ready_mutate_lock();
264
265 // Adjust the ready queue size
266 ready_queue_shrink( this.cltr );
267
268 // Make sure we aren't on the idle queue
269 unsafe_remove( this.cltr->idles, &this );
270
271 // Unlock the RWlock
272 ready_mutate_unlock( last_size );
273
274 // Finally we don't need the read_lock any more
275 unregister((__processor_id_t*)&this);
276}
277
278void ?{}(processor & this, const char name[], cluster & _cltr) {
279 ( this.idle ){};
280 ( this.terminated ){ 0 };
281 ( this.runner ){};
282 init( this, name, _cltr );
283
284 __cfadbg_print_safe(runtime_core, "Kernel : Starting core %p\n", &this);
285
286 this.stack = __create_pthread( &this.kernel_thread, __invoke_processor, (void *)&this );
287
288}
289
290void ^?{}(processor & this) with( this ){
291 if( ! __atomic_load_n(&do_terminate, __ATOMIC_ACQUIRE) ) {
292 __cfadbg_print_safe(runtime_core, "Kernel : core %p signaling termination\n", &this);
293
294 __atomic_store_n(&do_terminate, true, __ATOMIC_RELAXED);
295 __wake_proc( &this );
296
297 P( terminated );
298 verify( kernelTLS.this_processor != &this);
299 }
300
301 int err = pthread_join( kernel_thread, 0p );
302 if( err != 0 ) abort("KERNEL ERROR: joining processor %p caused error %s\n", &this, strerror(err));
303
304 free( this.stack );
305
306 deinit( this );
307
308 __atomic_fetch_sub( &cltr->nprocessors, 1u, __ATOMIC_SEQ_CST );
309}
310
311void ?{}(cluster & this, const char name[], Duration preemption_rate, unsigned io_flags) with( this ) {
312 this.name = name;
313 this.preemption_rate = preemption_rate;
314 this.nprocessors = 0;
315 ready_queue{};
316
317 #if !defined(__CFA_NO_STATISTICS__)
318 print_stats = 0;
319 stats = alloc();
320 __init_stats( stats );
321 #endif
322
323 threads{ __get };
324
325 __kernel_io_startup( this, io_flags, &this == mainCluster );
326
327 doregister(this);
328}
329
330void ^?{}(cluster & this) {
331 __kernel_io_shutdown( this, &this == mainCluster );
332
333 #if !defined(__CFA_NO_STATISTICS__)
334 if( 0 != this.print_stats ) {
335 __print_stats( this.stats, this.print_stats, true, this.name, (void*)&this );
336 }
337 free( this.stats );
338 #endif
339
340 unregister(this);
341}
342
343//=============================================================================================
344// Kernel Scheduling logic
345//=============================================================================================
346//Main of the processor contexts
347void main(processorCtx_t & runner) {
348 // Because of a bug, we couldn't initialized the seed on construction
349 // Do it here
350 kernelTLS.rand_seed ^= rdtscl();
351
352 processor * this = runner.proc;
353 verify(this);
354
355 __cfadbg_print_safe(runtime_core, "Kernel : core %p starting\n", this);
356 #if !defined(__CFA_NO_STATISTICS__)
357 if( this->print_halts ) {
358 __cfaabi_bits_print_safe( STDOUT_FILENO, "Processor : %d - %s (%p)\n", this->id, this->name, (void*)this);
359 }
360 #endif
361
362 {
363 // Setup preemption data
364 preemption_scope scope = { this };
365
366 __cfadbg_print_safe(runtime_core, "Kernel : core %p started\n", this);
367
368 $thread * readyThread = 0p;
369 for( unsigned int spin_count = 0;; spin_count++ ) {
370 // Try to get the next thread
371 readyThread = __next_thread( this->cltr );
372
373 // Check if we actually found a thread
374 if( readyThread ) {
375 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
376 /* paranoid */ verifyf( readyThread->state == Ready || readyThread->preempted != __NO_PREEMPTION, "state : %d, preempted %d\n", readyThread->state, readyThread->preempted);
377 /* paranoid */ verifyf( readyThread->link.next == 0p, "Expected null got %p", readyThread->link.next );
378 __builtin_prefetch( readyThread->context.SP );
379
380 // We found a thread run it
381 __run_thread(this, readyThread);
382
383 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
384 }
385
386 if(__atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST)) break;
387
388 if( !readyThread ) {
389 // Block until a thread is ready
390 __halt(this);
391 }
392 }
393
394 __cfadbg_print_safe(runtime_core, "Kernel : core %p stopping\n", this);
395 }
396
397 V( this->terminated );
398
399 if(this == mainProcessor) {
400 // HACK : the coroutine context switch expects this_thread to be set
401 // and it make sense for it to be set in all other cases except here
402 // fake it
403 kernelTLS.this_thread = mainThread;
404 }
405
406 __cfadbg_print_safe(runtime_core, "Kernel : core %p terminated\n", this);
407}
408
409static int * __volatile_errno() __attribute__((noinline));
410static int * __volatile_errno() { asm(""); return &errno; }
411
412// KERNEL ONLY
413// runThread runs a thread by context switching
414// from the processor coroutine to the target thread
415static void __run_thread(processor * this, $thread * thrd_dst) {
416 $coroutine * proc_cor = get_coroutine(this->runner);
417
418 // Update global state
419 kernelTLS.this_thread = thrd_dst;
420
421 // set state of processor coroutine to inactive
422 verify(proc_cor->state == Active);
423 proc_cor->state = Blocked;
424
425 // Actually run the thread
426 RUNNING: while(true) {
427 thrd_dst->preempted = __NO_PREEMPTION;
428 thrd_dst->state = Active;
429
430 __cfaabi_dbg_debug_do(
431 thrd_dst->park_stale = true;
432 thrd_dst->unpark_stale = true;
433 )
434
435 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
436 /* paranoid */ verify( kernelTLS.this_thread == thrd_dst );
437 /* 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
438 /* 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
439
440 // set context switch to the thread that the processor is executing
441 verify( thrd_dst->context.SP );
442 __cfactx_switch( &proc_cor->context, &thrd_dst->context );
443 // when __cfactx_switch returns we are back in the processor coroutine
444
445 /* 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 );
446 /* 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 );
447 /* paranoid */ verify( kernelTLS.this_thread == thrd_dst );
448 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
449
450
451 // We just finished running a thread, there are a few things that could have happened.
452 // 1 - Regular case : the thread has blocked and now one has scheduled it yet.
453 // 2 - Racy case : the thread has blocked but someone has already tried to schedule it.
454 // 4 - Preempted
455 // In case 1, we may have won a race so we can't write to the state again.
456 // In case 2, we lost the race so we now own the thread.
457
458 if(unlikely(thrd_dst->preempted != __NO_PREEMPTION)) {
459 // The thread was preempted, reschedule it and reset the flag
460 __schedule_thread( (__processor_id_t*)this, thrd_dst );
461 break RUNNING;
462 }
463
464 if(unlikely(thrd_dst->state == Halted)) {
465 // The thread has halted, it should never be scheduled/run again
466 // We may need to wake someone up here since
467 unpark( this->destroyer __cfaabi_dbg_ctx2 );
468 this->destroyer = 0p;
469 break RUNNING;
470 }
471
472 /* paranoid */ verify( thrd_dst->state == Active );
473 thrd_dst->state = Blocked;
474
475 // set state of processor coroutine to active and the thread to inactive
476 int old_ticket = __atomic_fetch_sub(&thrd_dst->ticket, 1, __ATOMIC_SEQ_CST);
477 __cfaabi_dbg_debug_do( thrd_dst->park_result = old_ticket; )
478 switch(old_ticket) {
479 case 1:
480 // This is case 1, the regular case, nothing more is needed
481 break RUNNING;
482 case 2:
483 // This is case 2, the racy case, someone tried to run this thread before it finished blocking
484 // In this case, just run it again.
485 continue RUNNING;
486 default:
487 // This makes no sense, something is wrong abort
488 abort();
489 }
490 }
491
492 // Just before returning to the processor, set the processor coroutine to active
493 proc_cor->state = Active;
494 kernelTLS.this_thread = 0p;
495}
496
497// KERNEL_ONLY
498void returnToKernel() {
499 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
500 $coroutine * proc_cor = get_coroutine(kernelTLS.this_processor->runner);
501 $thread * thrd_src = kernelTLS.this_thread;
502
503 #if !defined(__CFA_NO_STATISTICS__)
504 struct processor * last_proc = kernelTLS.this_processor;
505 #endif
506
507 // Run the thread on this processor
508 {
509 int local_errno = *__volatile_errno();
510 #if defined( __i386 ) || defined( __x86_64 )
511 __x87_store;
512 #endif
513 verify( proc_cor->context.SP );
514 __cfactx_switch( &thrd_src->context, &proc_cor->context );
515 #if defined( __i386 ) || defined( __x86_64 )
516 __x87_load;
517 #endif
518 *__volatile_errno() = local_errno;
519 }
520
521 #if !defined(__CFA_NO_STATISTICS__)
522 if(last_proc != kernelTLS.this_processor) {
523 __tls_stats()->ready.threads.migration++;
524 }
525 #endif
526
527 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
528 /* 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 );
529 /* 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 );
530}
531
532// KERNEL_ONLY
533// Context invoker for processors
534// This is the entry point for processors (kernel threads)
535// It effectively constructs a coroutine by stealing the pthread stack
536static void * __invoke_processor(void * arg) {
537 #if !defined( __CFA_NO_STATISTICS__ )
538 __stats_t local_stats;
539 __init_stats( &local_stats );
540 kernelTLS.this_stats = &local_stats;
541 #endif
542
543 processor * proc = (processor *) arg;
544 kernelTLS.this_processor = proc;
545 kernelTLS.this_thread = 0p;
546 kernelTLS.preemption_state.[enabled, disable_count] = [false, 1];
547 // SKULLDUGGERY: We want to create a context for the processor coroutine
548 // which is needed for the 2-step context switch. However, there is no reason
549 // to waste the perfectly valid stack create by pthread.
550 current_stack_info_t info;
551 __stack_t ctx;
552 info.storage = &ctx;
553 (proc->runner){ proc, &info };
554
555 __cfaabi_dbg_print_safe("Coroutine : created stack %p\n", get_coroutine(proc->runner)->stack.storage);
556
557 //Set global state
558 kernelTLS.this_thread = 0p;
559
560 //We now have a proper context from which to schedule threads
561 __cfadbg_print_safe(runtime_core, "Kernel : core %p created (%p, %p)\n", proc, &proc->runner, &ctx);
562
563 // SKULLDUGGERY: Since the coroutine doesn't have its own stack, we can't
564 // resume it to start it like it normally would, it will just context switch
565 // back to here. Instead directly call the main since we already are on the
566 // appropriate stack.
567 get_coroutine(proc->runner)->state = Active;
568 main( proc->runner );
569 get_coroutine(proc->runner)->state = Halted;
570
571 // Main routine of the core returned, the core is now fully terminated
572 __cfadbg_print_safe(runtime_core, "Kernel : core %p main ended (%p)\n", proc, &proc->runner);
573
574 #if !defined(__CFA_NO_STATISTICS__)
575 __tally_stats(proc->cltr->stats, &local_stats);
576 if( 0 != proc->print_stats ) {
577 __print_stats( &local_stats, proc->print_stats, true, proc->name, (void*)proc );
578 }
579 #endif
580
581 return 0p;
582}
583
584static void Abort( int ret, const char func[] ) {
585 if ( ret ) { // pthread routines return errno values
586 abort( "%s : internal error, error(%d) %s.", func, ret, strerror( ret ) );
587 } // if
588} // Abort
589
590void * __create_pthread( pthread_t * pthread, void * (*start)(void *), void * arg ) {
591 pthread_attr_t attr;
592
593 Abort( pthread_attr_init( &attr ), "pthread_attr_init" ); // initialize attribute
594
595 size_t stacksize;
596 // default stack size, normally defined by shell limit
597 Abort( pthread_attr_getstacksize( &attr, &stacksize ), "pthread_attr_getstacksize" );
598 assert( stacksize >= PTHREAD_STACK_MIN );
599
600 void * stack;
601 __cfaabi_dbg_debug_do(
602 stack = memalign( __page_size, stacksize + __page_size );
603 // pthread has no mechanism to create the guard page in user supplied stack.
604 if ( mprotect( stack, __page_size, PROT_NONE ) == -1 ) {
605 abort( "mprotect : internal error, mprotect failure, error(%d) %s.", errno, strerror( errno ) );
606 } // if
607 );
608 __cfaabi_dbg_no_debug_do(
609 stack = malloc( stacksize );
610 );
611
612 Abort( pthread_attr_setstack( &attr, stack, stacksize ), "pthread_attr_setstack" );
613
614 Abort( pthread_create( pthread, &attr, start, arg ), "pthread_create" );
615 return stack;
616}
617
618// KERNEL_ONLY
619static void __kernel_first_resume( processor * this ) {
620 $thread * src = mainThread;
621 $coroutine * dst = get_coroutine(this->runner);
622
623 verify( ! kernelTLS.preemption_state.enabled );
624
625 kernelTLS.this_thread->curr_cor = dst;
626 __stack_prepare( &dst->stack, 65000 );
627 __cfactx_start(main, dst, this->runner, __cfactx_invoke_coroutine);
628
629 verify( ! kernelTLS.preemption_state.enabled );
630
631 dst->last = &src->self_cor;
632 dst->starter = dst->starter ? dst->starter : &src->self_cor;
633
634 // make sure the current state is still correct
635 /* paranoid */ verify(src->state == Ready);
636
637 // context switch to specified coroutine
638 verify( dst->context.SP );
639 __cfactx_switch( &src->context, &dst->context );
640 // when __cfactx_switch returns we are back in the src coroutine
641
642 mainThread->curr_cor = &mainThread->self_cor;
643
644 // make sure the current state has been update
645 /* paranoid */ verify(src->state == Active);
646
647 verify( ! kernelTLS.preemption_state.enabled );
648}
649
650// KERNEL_ONLY
651static void __kernel_last_resume( processor * this ) {
652 $coroutine * src = &mainThread->self_cor;
653 $coroutine * dst = get_coroutine(this->runner);
654
655 verify( ! kernelTLS.preemption_state.enabled );
656 verify( dst->starter == src );
657 verify( dst->context.SP );
658
659 // SKULLDUGGERY in debug the processors check that the
660 // stack is still within the limit of the stack limits after running a thread.
661 // that check doesn't make sense if we context switch to the processor using the
662 // coroutine semantics. Since this is a special case, use the current context
663 // info to populate these fields.
664 __cfaabi_dbg_debug_do(
665 __stack_context_t ctx;
666 CtxGet( ctx );
667 mainThread->context.SP = ctx.SP;
668 mainThread->context.FP = ctx.FP;
669 )
670
671 // context switch to the processor
672 __cfactx_switch( &src->context, &dst->context );
673}
674
675//-----------------------------------------------------------------------------
676// Scheduler routines
677// KERNEL ONLY
678void __schedule_thread( struct __processor_id_t * id, $thread * thrd ) {
679 /* paranoid */ verify( thrd );
680 /* paranoid */ verify( thrd->state != Halted );
681 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
682 /* paranoid */ #if defined( __CFA_WITH_VERIFY__ )
683 /* paranoid */ if( thrd->state == Blocked || thrd->state == Start ) assertf( thrd->preempted == __NO_PREEMPTION,
684 "Error inactive thread marked as preempted, state %d, preemption %d\n", thrd->state, thrd->preempted );
685 /* paranoid */ if( thrd->preempted != __NO_PREEMPTION ) assertf(thrd->state == Active,
686 "Error preempted thread marked as not currently running, state %d, preemption %d\n", thrd->state, thrd->preempted );
687 /* paranoid */ #endif
688 /* paranoid */ verifyf( thrd->link.next == 0p, "Expected null got %p", thrd->link.next );
689
690 if (thrd->preempted == __NO_PREEMPTION) thrd->state = Ready;
691
692 ready_schedule_lock ( id );
693 push( thrd->curr_cluster, thrd );
694
695 #if !defined(__CFA_NO_STATISTICS__)
696 bool woke =
697 #endif
698 __wake_one(id, thrd->curr_cluster);
699
700 #if !defined(__CFA_NO_STATISTICS__)
701 if(woke) __tls_stats()->ready.sleep.wakes++;
702 #endif
703 ready_schedule_unlock( id );
704
705 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
706}
707
708// KERNEL ONLY
709static $thread * __next_thread(cluster * this) with( *this ) {
710 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
711
712 ready_schedule_lock ( (__processor_id_t*)kernelTLS.this_processor );
713 $thread * head = pop( this );
714 ready_schedule_unlock( (__processor_id_t*)kernelTLS.this_processor );
715
716 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
717 return head;
718}
719
720// KERNEL ONLY
721static bool __has_next_thread(cluster * this) with( *this ) {
722 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
723
724 ready_schedule_lock ( (__processor_id_t*)kernelTLS.this_processor );
725 bool not_empty = query( this );
726 ready_schedule_unlock( (__processor_id_t*)kernelTLS.this_processor );
727
728 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
729 return not_empty;
730}
731
732// KERNEL ONLY unpark with out disabling interrupts
733void __unpark( struct __processor_id_t * id, $thread * thrd __cfaabi_dbg_ctx_param2 ) {
734 // record activity
735 __cfaabi_dbg_record_thrd( *thrd, false, caller );
736
737 int old_ticket = __atomic_fetch_add(&thrd->ticket, 1, __ATOMIC_SEQ_CST);
738 __cfaabi_dbg_debug_do( thrd->unpark_result = old_ticket; thrd->unpark_state = thrd->state; )
739 switch(old_ticket) {
740 case 1:
741 // Wake won the race, the thread will reschedule/rerun itself
742 break;
743 case 0:
744 /* paranoid */ verify( ! thrd->preempted != __NO_PREEMPTION );
745 /* paranoid */ verify( thrd->state == Blocked );
746
747 // Wake lost the race,
748 __schedule_thread( id, thrd );
749 break;
750 default:
751 // This makes no sense, something is wrong abort
752 abort();
753 }
754}
755
756void unpark( $thread * thrd __cfaabi_dbg_ctx_param2 ) {
757 if( !thrd ) return;
758
759 disable_interrupts();
760 __unpark( (__processor_id_t*)kernelTLS.this_processor, thrd __cfaabi_dbg_ctx_fwd2 );
761 enable_interrupts( __cfaabi_dbg_ctx );
762}
763
764void park( __cfaabi_dbg_ctx_param ) {
765 /* paranoid */ verify( kernelTLS.preemption_state.enabled );
766 disable_interrupts();
767 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
768 /* paranoid */ verify( kernelTLS.this_thread->preempted == __NO_PREEMPTION );
769
770 // record activity
771 __cfaabi_dbg_record_thrd( *kernelTLS.this_thread, true, caller );
772
773 returnToKernel();
774
775 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
776 enable_interrupts( __cfaabi_dbg_ctx );
777 /* paranoid */ verify( kernelTLS.preemption_state.enabled );
778
779}
780
781// KERNEL ONLY
782void __leave_thread() {
783 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
784 returnToKernel();
785 abort();
786}
787
788// KERNEL ONLY
789bool force_yield( __Preemption_Reason reason ) {
790 /* paranoid */ verify( kernelTLS.preemption_state.enabled );
791 disable_interrupts();
792 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
793
794 $thread * thrd = kernelTLS.this_thread;
795 /* paranoid */ verify(thrd->state == Active);
796
797 // SKULLDUGGERY: It is possible that we are preempting this thread just before
798 // it was going to park itself. If that is the case and it is already using the
799 // intrusive fields then we can't use them to preempt the thread
800 // If that is the case, abandon the preemption.
801 bool preempted = false;
802 if(thrd->link.next == 0p) {
803 preempted = true;
804 thrd->preempted = reason;
805 returnToKernel();
806 }
807
808 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
809 enable_interrupts_noPoll();
810 /* paranoid */ verify( kernelTLS.preemption_state.enabled );
811
812 return preempted;
813}
814
815//=============================================================================================
816// Kernel Setup logic
817//=============================================================================================
818//-----------------------------------------------------------------------------
819// Kernel boot procedures
820static void __kernel_startup(void) {
821 verify( ! kernelTLS.preemption_state.enabled );
822 __cfadbg_print_safe(runtime_core, "Kernel : Starting\n");
823
824 __page_size = sysconf( _SC_PAGESIZE );
825
826 __cfa_dbg_global_clusters.list{ __get };
827 __cfa_dbg_global_clusters.lock{};
828
829 // Initialize the global scheduler lock
830 __scheduler_lock = (__scheduler_RWLock_t*)&storage___scheduler_lock;
831 (*__scheduler_lock){};
832
833 // Initialize the main cluster
834 mainCluster = (cluster *)&storage_mainCluster;
835 (*mainCluster){"Main Cluster"};
836
837 __cfadbg_print_safe(runtime_core, "Kernel : Main cluster ready\n");
838
839 // Start by initializing the main thread
840 // SKULLDUGGERY: the mainThread steals the process main thread
841 // which will then be scheduled by the mainProcessor normally
842 mainThread = ($thread *)&storage_mainThread;
843 current_stack_info_t info;
844 info.storage = (__stack_t*)&storage_mainThreadCtx;
845 (*mainThread){ &info };
846
847 __cfadbg_print_safe(runtime_core, "Kernel : Main thread ready\n");
848
849
850
851 // Construct the processor context of the main processor
852 void ?{}(processorCtx_t & this, processor * proc) {
853 (this.__cor){ "Processor" };
854 this.__cor.starter = 0p;
855 this.proc = proc;
856 }
857
858 void ?{}(processor & this) with( this ) {
859 ( this.idle ){};
860 ( this.terminated ){ 0 };
861 ( this.runner ){};
862 init( this, "Main Processor", *mainCluster );
863 kernel_thread = pthread_self();
864
865 runner{ &this };
866 __cfadbg_print_safe(runtime_core, "Kernel : constructed main processor context %p\n", &runner);
867 }
868
869 // Initialize the main processor and the main processor ctx
870 // (the coroutine that contains the processing control flow)
871 mainProcessor = (processor *)&storage_mainProcessor;
872 (*mainProcessor){};
873
874 //initialize the global state variables
875 kernelTLS.this_processor = mainProcessor;
876 kernelTLS.this_thread = mainThread;
877
878 #if !defined( __CFA_NO_STATISTICS__ )
879 kernelTLS.this_stats = (__stats_t *)& storage_mainProcStats;
880 __init_stats( kernelTLS.this_stats );
881 #endif
882
883 // Enable preemption
884 kernel_start_preemption();
885
886 // Add the main thread to the ready queue
887 // once resume is called on mainProcessor->runner the mainThread needs to be scheduled like any normal thread
888 __schedule_thread((__processor_id_t *)mainProcessor, mainThread);
889
890 // SKULLDUGGERY: Force a context switch to the main processor to set the main thread's context to the current UNIX
891 // context. Hence, the main thread does not begin through __cfactx_invoke_thread, like all other threads. The trick here is that
892 // mainThread is on the ready queue when this call is made.
893 __kernel_first_resume( kernelTLS.this_processor );
894
895
896 // THE SYSTEM IS NOW COMPLETELY RUNNING
897
898
899 // Now that the system is up, finish creating systems that need threading
900 __kernel_io_finish_start( *mainCluster );
901
902
903 __cfadbg_print_safe(runtime_core, "Kernel : Started\n--------------------------------------------------\n\n");
904
905 verify( ! kernelTLS.preemption_state.enabled );
906 enable_interrupts( __cfaabi_dbg_ctx );
907 verify( TL_GET( preemption_state.enabled ) );
908}
909
910static void __kernel_shutdown(void) {
911 //Before we start shutting things down, wait for systems that need threading to shutdown
912 __kernel_io_prepare_stop( *mainCluster );
913
914 /* paranoid */ verify( TL_GET( preemption_state.enabled ) );
915 disable_interrupts();
916 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
917
918 __cfadbg_print_safe(runtime_core, "\n--------------------------------------------------\nKernel : Shutting down\n");
919
920 // SKULLDUGGERY: Notify the mainProcessor it needs to terminates.
921 // When its coroutine terminates, it return control to the mainThread
922 // which is currently here
923 __atomic_store_n(&mainProcessor->do_terminate, true, __ATOMIC_RELEASE);
924 __kernel_last_resume( kernelTLS.this_processor );
925 mainThread->self_cor.state = Halted;
926
927 // THE SYSTEM IS NOW COMPLETELY STOPPED
928
929 // Disable preemption
930 kernel_stop_preemption();
931
932 // Destroy the main processor and its context in reverse order of construction
933 // These were manually constructed so we need manually destroy them
934 void ^?{}(processor & this) with( this ){
935 deinit( this );
936
937 /* paranoid */ verify( this.do_terminate == true );
938 __atomic_fetch_sub( &cltr->nprocessors, 1u, __ATOMIC_SEQ_CST );
939 __cfaabi_dbg_print_safe("Kernel : destroyed main processor context %p\n", &runner);
940 }
941
942 ^(*mainProcessor){};
943
944 // Final step, destroy the main thread since it is no longer needed
945
946 // Since we provided a stack to this taxk it will not destroy anything
947 /* paranoid */ verify(mainThread->self_cor.stack.storage == (__stack_t*)(((uintptr_t)&storage_mainThreadCtx)| 0x1));
948 ^(*mainThread){};
949
950 ^(*mainCluster){};
951
952 ^(*__scheduler_lock){};
953
954 ^(__cfa_dbg_global_clusters.list){};
955 ^(__cfa_dbg_global_clusters.lock){};
956
957 __cfadbg_print_safe(runtime_core, "Kernel : Shutdown complete\n");
958}
959
960//=============================================================================================
961// Kernel Idle Sleep
962//=============================================================================================
963// Wake a thread from the front if there are any
964static bool __wake_one(struct __processor_id_t * id, cluster * this) {
965 /* paranoid */ verify( ready_schedule_islocked( id ) );
966
967 // Check if there is a sleeping processor
968 processor * p = pop(this->idles);
969
970 // If no one is sleeping, we are done
971 if( 0p == p ) return false;
972
973 // We found a processor, wake it up
974 post( p->idle );
975
976 return true;
977}
978
979// Unconditionnaly wake a thread
980static bool __wake_proc(processor * this) {
981 __cfadbg_print_safe(runtime_core, "Kernel : waking Processor %p\n", this);
982
983 disable_interrupts();
984 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
985 bool ret = post( this->idle );
986 enable_interrupts( __cfaabi_dbg_ctx );
987
988 return ret;
989}
990
991static void __halt(processor * this) with( *this ) {
992 if( do_terminate ) return;
993
994 #if !defined(__CFA_NO_STATISTICS__)
995 __tls_stats()->ready.sleep.halts++;
996 #endif
997 // Push self to queue
998 push(cltr->idles, *this);
999
1000 // Makre sure we don't miss a thread
1001 if( __has_next_thread(cltr) ) {
1002 // A thread was posted, make sure a processor is woken up
1003 struct __processor_id_t *id = (struct __processor_id_t *) this;
1004 ready_schedule_lock ( id );
1005 __wake_one( id, cltr );
1006 ready_schedule_unlock( id );
1007 #if !defined(__CFA_NO_STATISTICS__)
1008 __tls_stats()->ready.sleep.cancels++;
1009 #endif
1010 }
1011
1012 #if !defined(__CFA_NO_STATISTICS__)
1013 if(this->print_halts) {
1014 __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 0\n", this->id, rdtscl());
1015 }
1016 #endif
1017
1018 wait( idle );
1019
1020 #if !defined(__CFA_NO_STATISTICS__)
1021 if(this->print_halts) {
1022 __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 1\n", this->id, rdtscl());
1023 }
1024 #endif
1025}
1026
1027//=============================================================================================
1028// Unexpected Terminating logic
1029//=============================================================================================
1030static __spinlock_t kernel_abort_lock;
1031static bool kernel_abort_called = false;
1032
1033void * kernel_abort(void) __attribute__ ((__nothrow__)) {
1034 // abort cannot be recursively entered by the same or different processors because all signal handlers return when
1035 // the globalAbort flag is true.
1036 lock( kernel_abort_lock __cfaabi_dbg_ctx2 );
1037
1038 // first task to abort ?
1039 if ( kernel_abort_called ) { // not first task to abort ?
1040 unlock( kernel_abort_lock );
1041
1042 sigset_t mask;
1043 sigemptyset( &mask );
1044 sigaddset( &mask, SIGALRM ); // block SIGALRM signals
1045 sigaddset( &mask, SIGUSR1 ); // block SIGALRM signals
1046 sigsuspend( &mask ); // block the processor to prevent further damage during abort
1047 _exit( EXIT_FAILURE ); // if processor unblocks before it is killed, terminate it
1048 }
1049 else {
1050 kernel_abort_called = true;
1051 unlock( kernel_abort_lock );
1052 }
1053
1054 return kernelTLS.this_thread;
1055}
1056
1057void kernel_abort_msg( void * kernel_data, char * abort_text, int abort_text_size ) {
1058 $thread * thrd = kernel_data;
1059
1060 if(thrd) {
1061 int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
1062 __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
1063
1064 if ( &thrd->self_cor != thrd->curr_cor ) {
1065 len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
1066 __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
1067 }
1068 else {
1069 __cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
1070 }
1071 }
1072 else {
1073 int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
1074 __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
1075 }
1076}
1077
1078int kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
1079 return get_coroutine(kernelTLS.this_thread) == get_coroutine(mainThread) ? 4 : 2;
1080}
1081
1082static __spinlock_t kernel_debug_lock;
1083
1084extern "C" {
1085 void __cfaabi_bits_acquire() {
1086 lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
1087 }
1088
1089 void __cfaabi_bits_release() {
1090 unlock( kernel_debug_lock );
1091 }
1092}
1093
1094//=============================================================================================
1095// Kernel Utilities
1096//=============================================================================================
1097//-----------------------------------------------------------------------------
1098// Locks
1099void ?{}( semaphore & this, int count = 1 ) {
1100 (this.lock){};
1101 this.count = count;
1102 (this.waiting){};
1103}
1104void ^?{}(semaphore & this) {}
1105
1106bool P(semaphore & this) with( this ){
1107 lock( lock __cfaabi_dbg_ctx2 );
1108 count -= 1;
1109 if ( count < 0 ) {
1110 // queue current task
1111 append( waiting, kernelTLS.this_thread );
1112
1113 // atomically release spin lock and block
1114 unlock( lock );
1115 park( __cfaabi_dbg_ctx );
1116 return true;
1117 }
1118 else {
1119 unlock( lock );
1120 return false;
1121 }
1122}
1123
1124bool V(semaphore & this) with( this ) {
1125 $thread * thrd = 0p;
1126 lock( lock __cfaabi_dbg_ctx2 );
1127 count += 1;
1128 if ( count <= 0 ) {
1129 // remove task at head of waiting list
1130 thrd = pop_head( waiting );
1131 }
1132
1133 unlock( lock );
1134
1135 // make new owner
1136 unpark( thrd __cfaabi_dbg_ctx2 );
1137
1138 return thrd != 0p;
1139}
1140
1141bool V(semaphore & this, unsigned diff) with( this ) {
1142 $thread * thrd = 0p;
1143 lock( lock __cfaabi_dbg_ctx2 );
1144 int release = max(-count, (int)diff);
1145 count += diff;
1146 for(release) {
1147 unpark( pop_head( waiting ) __cfaabi_dbg_ctx2 );
1148 }
1149
1150 unlock( lock );
1151
1152 return thrd != 0p;
1153}
1154
1155//-----------------------------------------------------------------------------
1156// Global Queues
1157void doregister( cluster & cltr ) {
1158 lock ( __cfa_dbg_global_clusters.lock __cfaabi_dbg_ctx2);
1159 push_front( __cfa_dbg_global_clusters.list, cltr );
1160 unlock ( __cfa_dbg_global_clusters.lock );
1161}
1162
1163void unregister( cluster & cltr ) {
1164 lock ( __cfa_dbg_global_clusters.lock __cfaabi_dbg_ctx2);
1165 remove( __cfa_dbg_global_clusters.list, cltr );
1166 unlock( __cfa_dbg_global_clusters.lock );
1167}
1168
1169void doregister( cluster * cltr, $thread & thrd ) {
1170 lock (cltr->thread_list_lock __cfaabi_dbg_ctx2);
1171 cltr->nthreads += 1;
1172 push_front(cltr->threads, thrd);
1173 unlock (cltr->thread_list_lock);
1174}
1175
1176void unregister( cluster * cltr, $thread & thrd ) {
1177 lock (cltr->thread_list_lock __cfaabi_dbg_ctx2);
1178 remove(cltr->threads, thrd );
1179 cltr->nthreads -= 1;
1180 unlock(cltr->thread_list_lock);
1181}
1182
1183//-----------------------------------------------------------------------------
1184// Debug
1185__cfaabi_dbg_debug_do(
1186 extern "C" {
1187 void __cfaabi_dbg_record_lock(__spinlock_t & this, const char prev_name[]) {
1188 this.prev_name = prev_name;
1189 this.prev_thrd = kernelTLS.this_thread;
1190 }
1191
1192 void __cfaabi_dbg_record_thrd($thread & this, bool park, const char prev_name[]) {
1193 if(park) {
1194 this.park_caller = prev_name;
1195 this.park_stale = false;
1196 }
1197 else {
1198 this.unpark_caller = prev_name;
1199 this.unpark_stale = false;
1200 }
1201 }
1202 }
1203)
1204
1205//-----------------------------------------------------------------------------
1206// Debug
1207bool threading_enabled(void) __attribute__((const)) {
1208 return true;
1209}
1210
1211//-----------------------------------------------------------------------------
1212// Statistics
1213#if !defined(__CFA_NO_STATISTICS__)
1214 void print_halts( processor & this ) {
1215 this.print_halts = true;
1216 }
1217#endif
1218// Local Variables: //
1219// mode: c //
1220// tab-width: 4 //
1221// End: //
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