source: libcfa/src/concurrency/kernel.cfa@ 3ac8b9f

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 3ac8b9f was f00b26d4, checked in by Thierry Delisle <tdelisle@…>, 5 years ago

Re-worked IO to use epoll and support multiple io_contexts per cluster.
Also redid how cluster options are handled.
Changed how iofwd calls are passed to support future features and io_contexts rework.
  • Property mode set to 100644
File size: 38.5 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(io_context, mainPollerThread);
133KERNEL_STORAGE(__scheduler_RWLock_t, __scheduler_lock);
134#if !defined(__CFA_NO_STATISTICS__)
135KERNEL_STORAGE(__stats_t, mainProcStats);
136#endif
137
138cluster * mainCluster;
139processor * mainProcessor;
140$thread * mainThread;
141__scheduler_RWLock_t * __scheduler_lock;
142
143extern "C" {
144 struct { __dllist_t(cluster) list; __spinlock_t lock; } __cfa_dbg_global_clusters;
145}
146
147size_t __page_size = 0;
148
149//-----------------------------------------------------------------------------
150// Global state
151thread_local struct KernelThreadData kernelTLS __attribute__ ((tls_model ( "initial-exec" ))) @= {
152 NULL, // cannot use 0p
153 NULL,
154 NULL,
155 { 1, false, false },
156};
157
158//-----------------------------------------------------------------------------
159// Struct to steal stack
160struct current_stack_info_t {
161 __stack_t * storage; // pointer to stack object
162 void * base; // base of stack
163 void * limit; // stack grows towards stack limit
164 void * context; // address of cfa_context_t
165};
166
167void ?{}( current_stack_info_t & this ) {
168 __stack_context_t ctx;
169 CtxGet( ctx );
170 this.base = ctx.FP;
171
172 rlimit r;
173 getrlimit( RLIMIT_STACK, &r);
174 size_t size = r.rlim_cur;
175
176 this.limit = (void *)(((intptr_t)this.base) - size);
177 this.context = &storage_mainThreadCtx;
178}
179
180//-----------------------------------------------------------------------------
181// Main thread construction
182
183void ?{}( $coroutine & this, current_stack_info_t * info) with( this ) {
184 stack.storage = info->storage;
185 with(*stack.storage) {
186 limit = info->limit;
187 base = info->base;
188 }
189 __attribute__((may_alias)) intptr_t * istorage = (intptr_t*) &stack.storage;
190 *istorage |= 0x1;
191 name = "Main Thread";
192 state = Start;
193 starter = 0p;
194 last = 0p;
195 cancellation = 0p;
196}
197
198void ?{}( $thread & this, current_stack_info_t * info) with( this ) {
199 ticket = 1;
200 state = Start;
201 self_cor{ info };
202 curr_cor = &self_cor;
203 curr_cluster = mainCluster;
204 self_mon.owner = &this;
205 self_mon.recursion = 1;
206 self_mon_p = &self_mon;
207 link.next = 0p;
208 link.prev = 0p;
209
210 node.next = 0p;
211 node.prev = 0p;
212 doregister(curr_cluster, this);
213
214 monitors{ &self_mon_p, 1, (fptr_t)0 };
215}
216
217//-----------------------------------------------------------------------------
218// Processor coroutine
219void ?{}(processorCtx_t & this) {
220
221}
222
223// Construct the processor context of non-main processors
224static void ?{}(processorCtx_t & this, processor * proc, current_stack_info_t * info) {
225 (this.__cor){ info };
226 this.proc = proc;
227}
228
229static void * __invoke_processor(void * arg);
230
231static init(processor & this, const char name[], cluster & _cltr) with( this ) {
232 this.name = name;
233 this.cltr = &_cltr;
234 id = -1u;
235 destroyer = 0p;
236 do_terminate = false;
237 preemption_alarm = 0p;
238 pending_preemption = false;
239
240 #if !defined(__CFA_NO_STATISTICS__)
241 print_stats = 0;
242 print_halts = false;
243 #endif
244
245 int target = __atomic_add_fetch( &cltr->nprocessors, 1u, __ATOMIC_SEQ_CST );
246
247 id = doregister((__processor_id_t*)&this);
248
249 // Lock the RWlock so no-one pushes/pops while we are changing the queue
250 uint_fast32_t last_size = ready_mutate_lock();
251
252 // Adjust the ready queue size
253 ready_queue_grow( cltr, target );
254
255 // Unlock the RWlock
256 ready_mutate_unlock( last_size );
257
258 __cfadbg_print_safe(runtime_core, "Kernel : core %p created\n", &this);
259}
260
261// Not a ctor, it just preps the destruction but should not destroy members
262void deinit(processor & this) {
263
264 int target = __atomic_sub_fetch( &this.cltr->nprocessors, 1u, __ATOMIC_SEQ_CST );
265
266 // Lock the RWlock so no-one pushes/pops while we are changing the queue
267 uint_fast32_t last_size = ready_mutate_lock();
268
269 // Adjust the ready queue size
270 ready_queue_shrink( this.cltr, target );
271
272 // Make sure we aren't on the idle queue
273 unsafe_remove( this.cltr->idles, &this );
274
275 // Unlock the RWlock
276 ready_mutate_unlock( last_size );
277
278 // Finally we don't need the read_lock any more
279 unregister((__processor_id_t*)&this);
280}
281
282void ?{}(processor & this, const char name[], cluster & _cltr) {
283 ( this.idle ){};
284 ( this.terminated ){ 0 };
285 ( this.runner ){};
286 init( this, name, _cltr );
287
288 __cfadbg_print_safe(runtime_core, "Kernel : Starting core %p\n", &this);
289
290 this.stack = __create_pthread( &this.kernel_thread, __invoke_processor, (void *)&this );
291
292}
293
294void ^?{}(processor & this) with( this ){
295 if( ! __atomic_load_n(&do_terminate, __ATOMIC_ACQUIRE) ) {
296 __cfadbg_print_safe(runtime_core, "Kernel : core %p signaling termination\n", &this);
297
298 __atomic_store_n(&do_terminate, true, __ATOMIC_RELAXED);
299 __wake_proc( &this );
300
301 P( terminated );
302 verify( kernelTLS.this_processor != &this);
303 }
304
305 int err = pthread_join( kernel_thread, 0p );
306 if( err != 0 ) abort("KERNEL ERROR: joining processor %p caused error %s\n", &this, strerror(err));
307
308 free( this.stack );
309
310 deinit( this );
311}
312
313void ?{}(cluster & this, const char name[], Duration preemption_rate, unsigned num_io, const io_context_params & io_params) with( this ) {
314 this.name = name;
315 this.preemption_rate = preemption_rate;
316 this.nprocessors = 0;
317 ready_queue{};
318
319 #if !defined(__CFA_NO_STATISTICS__)
320 print_stats = 0;
321 stats = alloc();
322 __init_stats( stats );
323 #endif
324
325 threads{ __get };
326
327 doregister(this);
328
329 // Lock the RWlock so no-one pushes/pops while we are changing the queue
330 uint_fast32_t last_size = ready_mutate_lock();
331
332 // Adjust the ready queue size
333 ready_queue_grow( &this, 0 );
334
335 // Unlock the RWlock
336 ready_mutate_unlock( last_size );
337
338 this.io.cnt = num_io;
339 this.io.ctxs = aalloc(num_io);
340 for(i; this.io.cnt) {
341 (this.io.ctxs[i]){ this, io_params };
342 }
343}
344
345void ^?{}(cluster & this) {
346 for(i; this.io.cnt) {
347 ^(this.io.ctxs[i]){ true };
348 }
349 free(this.io.ctxs);
350
351 // Lock the RWlock so no-one pushes/pops while we are changing the queue
352 uint_fast32_t last_size = ready_mutate_lock();
353
354 // Adjust the ready queue size
355 ready_queue_shrink( &this, 0 );
356
357 // Unlock the RWlock
358 ready_mutate_unlock( last_size );
359
360 #if !defined(__CFA_NO_STATISTICS__)
361 if( 0 != this.print_stats ) {
362 __print_stats( this.stats, this.print_stats, true, this.name, (void*)&this );
363 }
364 free( this.stats );
365 #endif
366
367 unregister(this);
368}
369
370//=============================================================================================
371// Kernel Scheduling logic
372//=============================================================================================
373//Main of the processor contexts
374void main(processorCtx_t & runner) {
375 // Because of a bug, we couldn't initialized the seed on construction
376 // Do it here
377 kernelTLS.rand_seed ^= rdtscl();
378
379 processor * this = runner.proc;
380 verify(this);
381
382 __cfadbg_print_safe(runtime_core, "Kernel : core %p starting\n", this);
383 #if !defined(__CFA_NO_STATISTICS__)
384 if( this->print_halts ) {
385 __cfaabi_bits_print_safe( STDOUT_FILENO, "Processor : %d - %s (%p)\n", this->id, this->name, (void*)this);
386 }
387 #endif
388
389 {
390 // Setup preemption data
391 preemption_scope scope = { this };
392
393 __cfadbg_print_safe(runtime_core, "Kernel : core %p started\n", this);
394
395 $thread * readyThread = 0p;
396 for( unsigned int spin_count = 0;; spin_count++ ) {
397 // Try to get the next thread
398 readyThread = __next_thread( this->cltr );
399
400 // Check if we actually found a thread
401 if( readyThread ) {
402 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
403 /* paranoid */ verifyf( readyThread->state == Ready || readyThread->preempted != __NO_PREEMPTION, "state : %d, preempted %d\n", readyThread->state, readyThread->preempted);
404 /* paranoid */ verifyf( readyThread->link.next == 0p, "Expected null got %p", readyThread->link.next );
405 __builtin_prefetch( readyThread->context.SP );
406
407 // We found a thread run it
408 __run_thread(this, readyThread);
409
410 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
411 }
412
413 if(__atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST)) break;
414
415 if( !readyThread ) {
416 // Block until a thread is ready
417 __halt(this);
418 }
419 }
420
421 __cfadbg_print_safe(runtime_core, "Kernel : core %p stopping\n", this);
422 }
423
424 V( this->terminated );
425
426 if(this == mainProcessor) {
427 // HACK : the coroutine context switch expects this_thread to be set
428 // and it make sense for it to be set in all other cases except here
429 // fake it
430 kernelTLS.this_thread = mainThread;
431 }
432
433 __cfadbg_print_safe(runtime_core, "Kernel : core %p terminated\n", this);
434}
435
436static int * __volatile_errno() __attribute__((noinline));
437static int * __volatile_errno() { asm(""); return &errno; }
438
439// KERNEL ONLY
440// runThread runs a thread by context switching
441// from the processor coroutine to the target thread
442static void __run_thread(processor * this, $thread * thrd_dst) {
443 $coroutine * proc_cor = get_coroutine(this->runner);
444
445 // Update global state
446 kernelTLS.this_thread = thrd_dst;
447
448 // set state of processor coroutine to inactive
449 verify(proc_cor->state == Active);
450 proc_cor->state = Blocked;
451
452 // Actually run the thread
453 RUNNING: while(true) {
454 thrd_dst->preempted = __NO_PREEMPTION;
455 thrd_dst->state = Active;
456
457 __cfaabi_dbg_debug_do(
458 thrd_dst->park_stale = true;
459 thrd_dst->unpark_stale = true;
460 )
461
462 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
463 /* paranoid */ verify( kernelTLS.this_thread == thrd_dst );
464 /* 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
465 /* 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
466
467 // set context switch to the thread that the processor is executing
468 verify( thrd_dst->context.SP );
469 __cfactx_switch( &proc_cor->context, &thrd_dst->context );
470 // when __cfactx_switch returns we are back in the processor coroutine
471
472 /* 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 );
473 /* 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 );
474 /* paranoid */ verify( kernelTLS.this_thread == thrd_dst );
475 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
476
477
478 // We just finished running a thread, there are a few things that could have happened.
479 // 1 - Regular case : the thread has blocked and now one has scheduled it yet.
480 // 2 - Racy case : the thread has blocked but someone has already tried to schedule it.
481 // 4 - Preempted
482 // In case 1, we may have won a race so we can't write to the state again.
483 // In case 2, we lost the race so we now own the thread.
484
485 if(unlikely(thrd_dst->preempted != __NO_PREEMPTION)) {
486 // The thread was preempted, reschedule it and reset the flag
487 __schedule_thread( (__processor_id_t*)this, thrd_dst );
488 break RUNNING;
489 }
490
491 if(unlikely(thrd_dst->state == Halted)) {
492 // The thread has halted, it should never be scheduled/run again
493 // We may need to wake someone up here since
494 unpark( this->destroyer __cfaabi_dbg_ctx2 );
495 this->destroyer = 0p;
496 break RUNNING;
497 }
498
499 /* paranoid */ verify( thrd_dst->state == Active );
500 thrd_dst->state = Blocked;
501
502 // set state of processor coroutine to active and the thread to inactive
503 int old_ticket = __atomic_fetch_sub(&thrd_dst->ticket, 1, __ATOMIC_SEQ_CST);
504 __cfaabi_dbg_debug_do( thrd_dst->park_result = old_ticket; )
505 switch(old_ticket) {
506 case 1:
507 // This is case 1, the regular case, nothing more is needed
508 break RUNNING;
509 case 2:
510 // This is case 2, the racy case, someone tried to run this thread before it finished blocking
511 // In this case, just run it again.
512 continue RUNNING;
513 default:
514 // This makes no sense, something is wrong abort
515 abort();
516 }
517 }
518
519 // Just before returning to the processor, set the processor coroutine to active
520 proc_cor->state = Active;
521 kernelTLS.this_thread = 0p;
522}
523
524// KERNEL_ONLY
525void returnToKernel() {
526 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
527 $coroutine * proc_cor = get_coroutine(kernelTLS.this_processor->runner);
528 $thread * thrd_src = kernelTLS.this_thread;
529
530 #if !defined(__CFA_NO_STATISTICS__)
531 struct processor * last_proc = kernelTLS.this_processor;
532 #endif
533
534 // Run the thread on this processor
535 {
536 int local_errno = *__volatile_errno();
537 #if defined( __i386 ) || defined( __x86_64 )
538 __x87_store;
539 #endif
540 verify( proc_cor->context.SP );
541 __cfactx_switch( &thrd_src->context, &proc_cor->context );
542 #if defined( __i386 ) || defined( __x86_64 )
543 __x87_load;
544 #endif
545 *__volatile_errno() = local_errno;
546 }
547
548 #if !defined(__CFA_NO_STATISTICS__)
549 if(last_proc != kernelTLS.this_processor) {
550 __tls_stats()->ready.threads.migration++;
551 }
552 #endif
553
554 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
555 /* 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 );
556 /* 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 );
557}
558
559// KERNEL_ONLY
560// Context invoker for processors
561// This is the entry point for processors (kernel threads)
562// It effectively constructs a coroutine by stealing the pthread stack
563static void * __invoke_processor(void * arg) {
564 #if !defined( __CFA_NO_STATISTICS__ )
565 __stats_t local_stats;
566 __init_stats( &local_stats );
567 kernelTLS.this_stats = &local_stats;
568 #endif
569
570 processor * proc = (processor *) arg;
571 kernelTLS.this_processor = proc;
572 kernelTLS.this_thread = 0p;
573 kernelTLS.preemption_state.[enabled, disable_count] = [false, 1];
574 // SKULLDUGGERY: We want to create a context for the processor coroutine
575 // which is needed for the 2-step context switch. However, there is no reason
576 // to waste the perfectly valid stack create by pthread.
577 current_stack_info_t info;
578 __stack_t ctx;
579 info.storage = &ctx;
580 (proc->runner){ proc, &info };
581
582 __cfaabi_dbg_print_safe("Coroutine : created stack %p\n", get_coroutine(proc->runner)->stack.storage);
583
584 //Set global state
585 kernelTLS.this_thread = 0p;
586
587 //We now have a proper context from which to schedule threads
588 __cfadbg_print_safe(runtime_core, "Kernel : core %p created (%p, %p)\n", proc, &proc->runner, &ctx);
589
590 // SKULLDUGGERY: Since the coroutine doesn't have its own stack, we can't
591 // resume it to start it like it normally would, it will just context switch
592 // back to here. Instead directly call the main since we already are on the
593 // appropriate stack.
594 get_coroutine(proc->runner)->state = Active;
595 main( proc->runner );
596 get_coroutine(proc->runner)->state = Halted;
597
598 // Main routine of the core returned, the core is now fully terminated
599 __cfadbg_print_safe(runtime_core, "Kernel : core %p main ended (%p)\n", proc, &proc->runner);
600
601 #if !defined(__CFA_NO_STATISTICS__)
602 __tally_stats(proc->cltr->stats, &local_stats);
603 if( 0 != proc->print_stats ) {
604 __print_stats( &local_stats, proc->print_stats, true, proc->name, (void*)proc );
605 }
606 #endif
607
608 return 0p;
609}
610
611static void Abort( int ret, const char func[] ) {
612 if ( ret ) { // pthread routines return errno values
613 abort( "%s : internal error, error(%d) %s.", func, ret, strerror( ret ) );
614 } // if
615} // Abort
616
617void * __create_pthread( pthread_t * pthread, void * (*start)(void *), void * arg ) {
618 pthread_attr_t attr;
619
620 Abort( pthread_attr_init( &attr ), "pthread_attr_init" ); // initialize attribute
621
622 size_t stacksize;
623 // default stack size, normally defined by shell limit
624 Abort( pthread_attr_getstacksize( &attr, &stacksize ), "pthread_attr_getstacksize" );
625 assert( stacksize >= PTHREAD_STACK_MIN );
626
627 void * stack;
628 __cfaabi_dbg_debug_do(
629 stack = memalign( __page_size, stacksize + __page_size );
630 // pthread has no mechanism to create the guard page in user supplied stack.
631 if ( mprotect( stack, __page_size, PROT_NONE ) == -1 ) {
632 abort( "mprotect : internal error, mprotect failure, error(%d) %s.", errno, strerror( errno ) );
633 } // if
634 );
635 __cfaabi_dbg_no_debug_do(
636 stack = malloc( stacksize );
637 );
638
639 Abort( pthread_attr_setstack( &attr, stack, stacksize ), "pthread_attr_setstack" );
640
641 Abort( pthread_create( pthread, &attr, start, arg ), "pthread_create" );
642 return stack;
643}
644
645// KERNEL_ONLY
646static void __kernel_first_resume( processor * this ) {
647 $thread * src = mainThread;
648 $coroutine * dst = get_coroutine(this->runner);
649
650 verify( ! kernelTLS.preemption_state.enabled );
651
652 kernelTLS.this_thread->curr_cor = dst;
653 __stack_prepare( &dst->stack, 65000 );
654 __cfactx_start(main, dst, this->runner, __cfactx_invoke_coroutine);
655
656 verify( ! kernelTLS.preemption_state.enabled );
657
658 dst->last = &src->self_cor;
659 dst->starter = dst->starter ? dst->starter : &src->self_cor;
660
661 // make sure the current state is still correct
662 /* paranoid */ verify(src->state == Ready);
663
664 // context switch to specified coroutine
665 verify( dst->context.SP );
666 __cfactx_switch( &src->context, &dst->context );
667 // when __cfactx_switch returns we are back in the src coroutine
668
669 mainThread->curr_cor = &mainThread->self_cor;
670
671 // make sure the current state has been update
672 /* paranoid */ verify(src->state == Active);
673
674 verify( ! kernelTLS.preemption_state.enabled );
675}
676
677// KERNEL_ONLY
678static void __kernel_last_resume( processor * this ) {
679 $coroutine * src = &mainThread->self_cor;
680 $coroutine * dst = get_coroutine(this->runner);
681
682 verify( ! kernelTLS.preemption_state.enabled );
683 verify( dst->starter == src );
684 verify( dst->context.SP );
685
686 // SKULLDUGGERY in debug the processors check that the
687 // stack is still within the limit of the stack limits after running a thread.
688 // that check doesn't make sense if we context switch to the processor using the
689 // coroutine semantics. Since this is a special case, use the current context
690 // info to populate these fields.
691 __cfaabi_dbg_debug_do(
692 __stack_context_t ctx;
693 CtxGet( ctx );
694 mainThread->context.SP = ctx.SP;
695 mainThread->context.FP = ctx.FP;
696 )
697
698 // context switch to the processor
699 __cfactx_switch( &src->context, &dst->context );
700}
701
702//-----------------------------------------------------------------------------
703// Scheduler routines
704// KERNEL ONLY
705void __schedule_thread( struct __processor_id_t * id, $thread * thrd ) {
706 /* paranoid */ verify( thrd );
707 /* paranoid */ verify( thrd->state != Halted );
708 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
709 /* paranoid */ #if defined( __CFA_WITH_VERIFY__ )
710 /* paranoid */ if( thrd->state == Blocked || thrd->state == Start ) assertf( thrd->preempted == __NO_PREEMPTION,
711 "Error inactive thread marked as preempted, state %d, preemption %d\n", thrd->state, thrd->preempted );
712 /* paranoid */ if( thrd->preempted != __NO_PREEMPTION ) assertf(thrd->state == Active,
713 "Error preempted thread marked as not currently running, state %d, preemption %d\n", thrd->state, thrd->preempted );
714 /* paranoid */ #endif
715 /* paranoid */ verifyf( thrd->link.next == 0p, "Expected null got %p", thrd->link.next );
716
717 if (thrd->preempted == __NO_PREEMPTION) thrd->state = Ready;
718
719 ready_schedule_lock ( id );
720 push( thrd->curr_cluster, thrd );
721
722 #if !defined(__CFA_NO_STATISTICS__)
723 bool woke =
724 #endif
725 __wake_one(id, thrd->curr_cluster);
726
727 #if !defined(__CFA_NO_STATISTICS__)
728 if(woke) __tls_stats()->ready.sleep.wakes++;
729 #endif
730 ready_schedule_unlock( id );
731
732 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
733}
734
735// KERNEL ONLY
736static $thread * __next_thread(cluster * this) with( *this ) {
737 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
738
739 ready_schedule_lock ( (__processor_id_t*)kernelTLS.this_processor );
740 $thread * head = pop( this );
741 ready_schedule_unlock( (__processor_id_t*)kernelTLS.this_processor );
742
743 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
744 return head;
745}
746
747// KERNEL ONLY
748static bool __has_next_thread(cluster * this) with( *this ) {
749 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
750
751 ready_schedule_lock ( (__processor_id_t*)kernelTLS.this_processor );
752 bool not_empty = query( this );
753 ready_schedule_unlock( (__processor_id_t*)kernelTLS.this_processor );
754
755 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
756 return not_empty;
757}
758
759// KERNEL ONLY unpark with out disabling interrupts
760void __unpark( struct __processor_id_t * id, $thread * thrd __cfaabi_dbg_ctx_param2 ) {
761 // record activity
762 __cfaabi_dbg_record_thrd( *thrd, false, caller );
763
764 int old_ticket = __atomic_fetch_add(&thrd->ticket, 1, __ATOMIC_SEQ_CST);
765 __cfaabi_dbg_debug_do( thrd->unpark_result = old_ticket; thrd->unpark_state = thrd->state; )
766 switch(old_ticket) {
767 case 1:
768 // Wake won the race, the thread will reschedule/rerun itself
769 break;
770 case 0:
771 /* paranoid */ verify( ! thrd->preempted != __NO_PREEMPTION );
772 /* paranoid */ verify( thrd->state == Blocked );
773
774 // Wake lost the race,
775 __schedule_thread( id, thrd );
776 break;
777 default:
778 // This makes no sense, something is wrong abort
779 abort();
780 }
781}
782
783void unpark( $thread * thrd __cfaabi_dbg_ctx_param2 ) {
784 if( !thrd ) return;
785
786 disable_interrupts();
787 __unpark( (__processor_id_t*)kernelTLS.this_processor, thrd __cfaabi_dbg_ctx_fwd2 );
788 enable_interrupts( __cfaabi_dbg_ctx );
789}
790
791void park( __cfaabi_dbg_ctx_param ) {
792 /* paranoid */ verify( kernelTLS.preemption_state.enabled );
793 disable_interrupts();
794 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
795 /* paranoid */ verify( kernelTLS.this_thread->preempted == __NO_PREEMPTION );
796
797 // record activity
798 __cfaabi_dbg_record_thrd( *kernelTLS.this_thread, true, caller );
799
800 returnToKernel();
801
802 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
803 enable_interrupts( __cfaabi_dbg_ctx );
804 /* paranoid */ verify( kernelTLS.preemption_state.enabled );
805
806}
807
808// KERNEL ONLY
809void __leave_thread() {
810 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
811 returnToKernel();
812 abort();
813}
814
815// KERNEL ONLY
816bool force_yield( __Preemption_Reason reason ) {
817 /* paranoid */ verify( kernelTLS.preemption_state.enabled );
818 disable_interrupts();
819 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
820
821 $thread * thrd = kernelTLS.this_thread;
822 /* paranoid */ verify(thrd->state == Active);
823
824 // SKULLDUGGERY: It is possible that we are preempting this thread just before
825 // it was going to park itself. If that is the case and it is already using the
826 // intrusive fields then we can't use them to preempt the thread
827 // If that is the case, abandon the preemption.
828 bool preempted = false;
829 if(thrd->link.next == 0p) {
830 preempted = true;
831 thrd->preempted = reason;
832 returnToKernel();
833 }
834
835 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
836 enable_interrupts_noPoll();
837 /* paranoid */ verify( kernelTLS.preemption_state.enabled );
838
839 return preempted;
840}
841
842//=============================================================================================
843// Kernel Setup logic
844//=============================================================================================
845//-----------------------------------------------------------------------------
846// Kernel boot procedures
847static void __kernel_startup(void) {
848 verify( ! kernelTLS.preemption_state.enabled );
849 __cfadbg_print_safe(runtime_core, "Kernel : Starting\n");
850
851 __page_size = sysconf( _SC_PAGESIZE );
852
853 __cfa_dbg_global_clusters.list{ __get };
854 __cfa_dbg_global_clusters.lock{};
855
856 // Initialize the global scheduler lock
857 __scheduler_lock = (__scheduler_RWLock_t*)&storage___scheduler_lock;
858 (*__scheduler_lock){};
859
860 // Initialize the main cluster
861 mainCluster = (cluster *)&storage_mainCluster;
862 (*mainCluster){"Main Cluster", 0};
863
864 __cfadbg_print_safe(runtime_core, "Kernel : Main cluster ready\n");
865
866 // Start by initializing the main thread
867 // SKULLDUGGERY: the mainThread steals the process main thread
868 // which will then be scheduled by the mainProcessor normally
869 mainThread = ($thread *)&storage_mainThread;
870 current_stack_info_t info;
871 info.storage = (__stack_t*)&storage_mainThreadCtx;
872 (*mainThread){ &info };
873
874 __cfadbg_print_safe(runtime_core, "Kernel : Main thread ready\n");
875
876
877
878 // Construct the processor context of the main processor
879 void ?{}(processorCtx_t & this, processor * proc) {
880 (this.__cor){ "Processor" };
881 this.__cor.starter = 0p;
882 this.proc = proc;
883 }
884
885 void ?{}(processor & this) with( this ) {
886 ( this.idle ){};
887 ( this.terminated ){ 0 };
888 ( this.runner ){};
889 init( this, "Main Processor", *mainCluster );
890 kernel_thread = pthread_self();
891
892 runner{ &this };
893 __cfadbg_print_safe(runtime_core, "Kernel : constructed main processor context %p\n", &runner);
894 }
895
896 // Initialize the main processor and the main processor ctx
897 // (the coroutine that contains the processing control flow)
898 mainProcessor = (processor *)&storage_mainProcessor;
899 (*mainProcessor){};
900
901 //initialize the global state variables
902 kernelTLS.this_processor = mainProcessor;
903 kernelTLS.this_thread = mainThread;
904
905 #if !defined( __CFA_NO_STATISTICS__ )
906 kernelTLS.this_stats = (__stats_t *)& storage_mainProcStats;
907 __init_stats( kernelTLS.this_stats );
908 #endif
909
910 // Start IO
911 __kernel_io_startup();
912
913 // Enable preemption
914 kernel_start_preemption();
915
916 // Add the main thread to the ready queue
917 // once resume is called on mainProcessor->runner the mainThread needs to be scheduled like any normal thread
918 __schedule_thread((__processor_id_t *)mainProcessor, mainThread);
919
920 // SKULLDUGGERY: Force a context switch to the main processor to set the main thread's context to the current UNIX
921 // context. Hence, the main thread does not begin through __cfactx_invoke_thread, like all other threads. The trick here is that
922 // mainThread is on the ready queue when this call is made.
923 __kernel_first_resume( kernelTLS.this_processor );
924
925
926 // THE SYSTEM IS NOW COMPLETELY RUNNING
927
928
929 // Now that the system is up, finish creating systems that need threading
930 mainCluster->io.ctxs = (io_context *)&storage_mainPollerThread;
931 mainCluster->io.cnt = 1;
932 (*mainCluster->io.ctxs){ *mainCluster };
933
934 __cfadbg_print_safe(runtime_core, "Kernel : Started\n--------------------------------------------------\n\n");
935
936 verify( ! kernelTLS.preemption_state.enabled );
937 enable_interrupts( __cfaabi_dbg_ctx );
938 verify( TL_GET( preemption_state.enabled ) );
939}
940
941static void __kernel_shutdown(void) {
942 //Before we start shutting things down, wait for systems that need threading to shutdown
943 ^(*mainCluster->io.ctxs){};
944 mainCluster->io.cnt = 0;
945 mainCluster->io.ctxs = 0p;
946
947 /* paranoid */ verify( TL_GET( preemption_state.enabled ) );
948 disable_interrupts();
949 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
950
951 __cfadbg_print_safe(runtime_core, "\n--------------------------------------------------\nKernel : Shutting down\n");
952
953 // SKULLDUGGERY: Notify the mainProcessor it needs to terminates.
954 // When its coroutine terminates, it return control to the mainThread
955 // which is currently here
956 __atomic_store_n(&mainProcessor->do_terminate, true, __ATOMIC_RELEASE);
957 __kernel_last_resume( kernelTLS.this_processor );
958 mainThread->self_cor.state = Halted;
959
960 // THE SYSTEM IS NOW COMPLETELY STOPPED
961
962 // Disable preemption
963 kernel_stop_preemption();
964
965 // Stop IO
966 __kernel_io_shutdown();
967
968 // Destroy the main processor and its context in reverse order of construction
969 // These were manually constructed so we need manually destroy them
970 void ^?{}(processor & this) with( this ){
971 deinit( this );
972
973 /* paranoid */ verify( this.do_terminate == true );
974 __cfaabi_dbg_print_safe("Kernel : destroyed main processor context %p\n", &runner);
975 }
976
977 ^(*mainProcessor){};
978
979 // Final step, destroy the main thread since it is no longer needed
980
981 // Since we provided a stack to this taxk it will not destroy anything
982 /* paranoid */ verify(mainThread->self_cor.stack.storage == (__stack_t*)(((uintptr_t)&storage_mainThreadCtx)| 0x1));
983 ^(*mainThread){};
984
985 ^(*mainCluster){};
986
987 ^(*__scheduler_lock){};
988
989 ^(__cfa_dbg_global_clusters.list){};
990 ^(__cfa_dbg_global_clusters.lock){};
991
992 __cfadbg_print_safe(runtime_core, "Kernel : Shutdown complete\n");
993}
994
995//=============================================================================================
996// Kernel Idle Sleep
997//=============================================================================================
998// Wake a thread from the front if there are any
999static bool __wake_one(struct __processor_id_t * id, cluster * this) {
1000 /* paranoid */ verify( ready_schedule_islocked( id ) );
1001
1002 // Check if there is a sleeping processor
1003 processor * p = pop(this->idles);
1004
1005 // If no one is sleeping, we are done
1006 if( 0p == p ) return false;
1007
1008 // We found a processor, wake it up
1009 post( p->idle );
1010
1011 return true;
1012}
1013
1014// Unconditionnaly wake a thread
1015static bool __wake_proc(processor * this) {
1016 __cfadbg_print_safe(runtime_core, "Kernel : waking Processor %p\n", this);
1017
1018 disable_interrupts();
1019 /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
1020 bool ret = post( this->idle );
1021 enable_interrupts( __cfaabi_dbg_ctx );
1022
1023 return ret;
1024}
1025
1026static void __halt(processor * this) with( *this ) {
1027 if( do_terminate ) return;
1028
1029 #if !defined(__CFA_NO_STATISTICS__)
1030 __tls_stats()->ready.sleep.halts++;
1031 #endif
1032 // Push self to queue
1033 push(cltr->idles, *this);
1034
1035 // Makre sure we don't miss a thread
1036 if( __has_next_thread(cltr) ) {
1037 // A thread was posted, make sure a processor is woken up
1038 struct __processor_id_t *id = (struct __processor_id_t *) this;
1039 ready_schedule_lock ( id );
1040 __wake_one( id, cltr );
1041 ready_schedule_unlock( id );
1042 #if !defined(__CFA_NO_STATISTICS__)
1043 __tls_stats()->ready.sleep.cancels++;
1044 #endif
1045 }
1046
1047 #if !defined(__CFA_NO_STATISTICS__)
1048 if(this->print_halts) {
1049 __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 0\n", this->id, rdtscl());
1050 }
1051 #endif
1052
1053 wait( idle );
1054
1055 #if !defined(__CFA_NO_STATISTICS__)
1056 if(this->print_halts) {
1057 __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 1\n", this->id, rdtscl());
1058 }
1059 #endif
1060}
1061
1062//=============================================================================================
1063// Unexpected Terminating logic
1064//=============================================================================================
1065static __spinlock_t kernel_abort_lock;
1066static bool kernel_abort_called = false;
1067
1068void * kernel_abort(void) __attribute__ ((__nothrow__)) {
1069 // abort cannot be recursively entered by the same or different processors because all signal handlers return when
1070 // the globalAbort flag is true.
1071 lock( kernel_abort_lock __cfaabi_dbg_ctx2 );
1072
1073 // first task to abort ?
1074 if ( kernel_abort_called ) { // not first task to abort ?
1075 unlock( kernel_abort_lock );
1076
1077 sigset_t mask;
1078 sigemptyset( &mask );
1079 sigaddset( &mask, SIGALRM ); // block SIGALRM signals
1080 sigaddset( &mask, SIGUSR1 ); // block SIGALRM signals
1081 sigsuspend( &mask ); // block the processor to prevent further damage during abort
1082 _exit( EXIT_FAILURE ); // if processor unblocks before it is killed, terminate it
1083 }
1084 else {
1085 kernel_abort_called = true;
1086 unlock( kernel_abort_lock );
1087 }
1088
1089 return kernelTLS.this_thread;
1090}
1091
1092void kernel_abort_msg( void * kernel_data, char * abort_text, int abort_text_size ) {
1093 $thread * thrd = kernel_data;
1094
1095 if(thrd) {
1096 int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
1097 __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
1098
1099 if ( &thrd->self_cor != thrd->curr_cor ) {
1100 len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
1101 __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
1102 }
1103 else {
1104 __cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
1105 }
1106 }
1107 else {
1108 int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
1109 __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
1110 }
1111}
1112
1113int kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
1114 return get_coroutine(kernelTLS.this_thread) == get_coroutine(mainThread) ? 4 : 2;
1115}
1116
1117static __spinlock_t kernel_debug_lock;
1118
1119extern "C" {
1120 void __cfaabi_bits_acquire() {
1121 lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
1122 }
1123
1124 void __cfaabi_bits_release() {
1125 unlock( kernel_debug_lock );
1126 }
1127}
1128
1129//=============================================================================================
1130// Kernel Utilities
1131//=============================================================================================
1132//-----------------------------------------------------------------------------
1133// Locks
1134void ?{}( semaphore & this, int count = 1 ) {
1135 (this.lock){};
1136 this.count = count;
1137 (this.waiting){};
1138}
1139void ^?{}(semaphore & this) {}
1140
1141bool P(semaphore & this) with( this ){
1142 lock( lock __cfaabi_dbg_ctx2 );
1143 count -= 1;
1144 if ( count < 0 ) {
1145 // queue current task
1146 append( waiting, kernelTLS.this_thread );
1147
1148 // atomically release spin lock and block
1149 unlock( lock );
1150 park( __cfaabi_dbg_ctx );
1151 return true;
1152 }
1153 else {
1154 unlock( lock );
1155 return false;
1156 }
1157}
1158
1159bool V(semaphore & this) with( this ) {
1160 $thread * thrd = 0p;
1161 lock( lock __cfaabi_dbg_ctx2 );
1162 count += 1;
1163 if ( count <= 0 ) {
1164 // remove task at head of waiting list
1165 thrd = pop_head( waiting );
1166 }
1167
1168 unlock( lock );
1169
1170 // make new owner
1171 unpark( thrd __cfaabi_dbg_ctx2 );
1172
1173 return thrd != 0p;
1174}
1175
1176bool V(semaphore & this, unsigned diff) with( this ) {
1177 $thread * thrd = 0p;
1178 lock( lock __cfaabi_dbg_ctx2 );
1179 int release = max(-count, (int)diff);
1180 count += diff;
1181 for(release) {
1182 unpark( pop_head( waiting ) __cfaabi_dbg_ctx2 );
1183 }
1184
1185 unlock( lock );
1186
1187 return thrd != 0p;
1188}
1189
1190//-----------------------------------------------------------------------------
1191// Global Queues
1192void doregister( cluster & cltr ) {
1193 lock ( __cfa_dbg_global_clusters.lock __cfaabi_dbg_ctx2);
1194 push_front( __cfa_dbg_global_clusters.list, cltr );
1195 unlock ( __cfa_dbg_global_clusters.lock );
1196}
1197
1198void unregister( cluster & cltr ) {
1199 lock ( __cfa_dbg_global_clusters.lock __cfaabi_dbg_ctx2);
1200 remove( __cfa_dbg_global_clusters.list, cltr );
1201 unlock( __cfa_dbg_global_clusters.lock );
1202}
1203
1204void doregister( cluster * cltr, $thread & thrd ) {
1205 lock (cltr->thread_list_lock __cfaabi_dbg_ctx2);
1206 cltr->nthreads += 1;
1207 push_front(cltr->threads, thrd);
1208 unlock (cltr->thread_list_lock);
1209}
1210
1211void unregister( cluster * cltr, $thread & thrd ) {
1212 lock (cltr->thread_list_lock __cfaabi_dbg_ctx2);
1213 remove(cltr->threads, thrd );
1214 cltr->nthreads -= 1;
1215 unlock(cltr->thread_list_lock);
1216}
1217
1218//-----------------------------------------------------------------------------
1219// Debug
1220__cfaabi_dbg_debug_do(
1221 extern "C" {
1222 void __cfaabi_dbg_record_lock(__spinlock_t & this, const char prev_name[]) {
1223 this.prev_name = prev_name;
1224 this.prev_thrd = kernelTLS.this_thread;
1225 }
1226
1227 void __cfaabi_dbg_record_thrd($thread & this, bool park, const char prev_name[]) {
1228 if(park) {
1229 this.park_caller = prev_name;
1230 this.park_stale = false;
1231 }
1232 else {
1233 this.unpark_caller = prev_name;
1234 this.unpark_stale = false;
1235 }
1236 }
1237 }
1238)
1239
1240//-----------------------------------------------------------------------------
1241// Debug
1242bool threading_enabled(void) __attribute__((const)) {
1243 return true;
1244}
1245
1246//-----------------------------------------------------------------------------
1247// Statistics
1248#if !defined(__CFA_NO_STATISTICS__)
1249 void print_halts( processor & this ) {
1250 this.print_halts = true;
1251 }
1252#endif
1253// Local Variables: //
1254// mode: c //
1255// tab-width: 4 //
1256// End: //
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