source: libcfa/src/concurrency/kernel.cfa @ 4e39f51

ADTarm-ehast-experimentalenumforall-pointer-decayjacob/cs343-translationnew-ast-unique-exprpthread-emulationqualifiedEnum
Last change on this file since 4e39f51 was 58d64a4, checked in by Thierry Delisle <tdelisle@…>, 4 years ago

processor_id_t now have a bool to state if it is a full processor.
kernelTLS.this_thread now has much tighter lifetime.
Remove warning in kernel.cfa

  • Property mode set to 100644
File size: 22.6 KB
RevLine 
[8118303]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
[75f3522]10// Created On       : Tue Jan 17 12:27:26 2017
[6b0b624]11// Last Modified By : Peter A. Buhr
[0190480]12// Last Modified On : Mon Aug 31 07:08:20 2020
13// Update Count     : 71
[8118303]14//
15
[2026bb6]16#define __cforall_thread__
[4069faad]17// #define __CFA_DEBUG_PRINT_RUNTIME_CORE__
[2026bb6]18
[8118303]19//C Includes
[214e8da]20#include <errno.h>
[9d944b2]21#include <stdio.h>
[58b6d1b]22#include <signal.h>
[9d944b2]23#include <unistd.h>
[8118303]24
25//CFA Includes
[73abe95]26#include "kernel_private.hfa"
27#include "preemption.hfa"
[8118303]28
29//Private includes
30#define __CFA_INVOKE_PRIVATE__
31#include "invoke.h"
32
[4069faad]33
[deca0f5]34//-----------------------------------------------------------------------------
35// Some assembly required
[1805b1b]36#if defined( __i386 )
[deca0f5]37        // mxcr : SSE Status and Control bits (control bits are preserved across function calls)
38        // fcw  : X87 FPU control word (preserved across function calls)
39        #define __x87_store         \
40                uint32_t __mxcr;      \
41                uint16_t __fcw;       \
42                __asm__ volatile (    \
43                        "stmxcsr %0\n"  \
44                        "fnstcw  %1\n"  \
45                        : "=m" (__mxcr),\
46                                "=m" (__fcw)  \
47                )
48
49        #define __x87_load         \
50                __asm__ volatile (   \
51                        "fldcw  %1\n"  \
52                        "ldmxcsr %0\n" \
53                        ::"m" (__mxcr),\
54                                "m" (__fcw)  \
55                )
56
57#elif defined( __x86_64 )
58        #define __x87_store         \
59                uint32_t __mxcr;      \
60                uint16_t __fcw;       \
61                __asm__ volatile (    \
62                        "stmxcsr %0\n"  \
63                        "fnstcw  %1\n"  \
64                        : "=m" (__mxcr),\
65                                "=m" (__fcw)  \
66                )
67
68        #define __x87_load          \
69                __asm__ volatile (    \
70                        "fldcw  %1\n"   \
71                        "ldmxcsr %0\n"  \
72                        :: "m" (__mxcr),\
73                                "m" (__fcw)  \
74                )
75
[0190480]76#elif defined( __arm__ )
77        #define __x87_store
78        #define __x87_load
79
80#elif defined( __aarch64__ )
[74f5c83]81        #define __x87_store              \
82                uint32_t __fpcntl[2];    \
83                __asm__ volatile (    \
84                        "mrs x9, FPCR\n" \
85                        "mrs x10, FPSR\n"  \
86                        "stp x9, x10, %0\n"  \
87                        : "=m" (__fpcntl) : : "x9", "x10" \
88                )
89
90        #define __x87_load         \
91                __asm__ volatile (    \
92                        "ldp x9, x10, %0\n"  \
93                        "msr FPSR, x10\n"  \
94                        "msr FPCR, x9\n" \
95                : "=m" (__fpcntl) : : "x9", "x10" \
96                )
97
[deca0f5]98#else
[0190480]99        #error unsupported hardware architecture
[deca0f5]100#endif
101
[e660761]102extern $thread * mainThread;
103extern processor * mainProcessor;
[2ac095d]104
[92e7631]105//-----------------------------------------------------------------------------
106// Kernel Scheduling logic
107static $thread * __next_thread(cluster * this);
[1eb239e4]108static $thread * __next_thread_slow(cluster * this);
[92e7631]109static void __run_thread(processor * this, $thread * dst);
[1eb239e4]110static void __wake_one(struct __processor_id_t * id, cluster * cltr);
111
112static void push  (__cluster_idles & idles, processor & proc);
113static void remove(__cluster_idles & idles, processor & proc);
114static [unsigned idle, unsigned total, * processor] query( & __cluster_idles idles );
115
[c84e80a]116
[75f3522]117//=============================================================================================
118// Kernel Scheduling logic
119//=============================================================================================
[8fcbb4c]120//Main of the processor contexts
[83a071f9]121void main(processorCtx_t & runner) {
[21184e3]122        // Because of a bug, we couldn't initialized the seed on construction
123        // Do it here
[7768b8d]124        kernelTLS.rand_seed ^= rdtscl();
[f2384c9a]125        kernelTLS.ready_rng.fwd_seed = 25214903917_l64u * (rdtscl() ^ (uintptr_t)&runner);
126        __tls_rand_advance_bck();
[21184e3]127
[83a071f9]128        processor * this = runner.proc;
[094476d]129        verify(this);
[c81ebf9]130
[4069faad]131        __cfadbg_print_safe(runtime_core, "Kernel : core %p starting\n", this);
[28d73c1]132        #if !defined(__CFA_NO_STATISTICS__)
133                if( this->print_halts ) {
134                        __cfaabi_bits_print_safe( STDOUT_FILENO, "Processor : %d - %s (%p)\n", this->id, this->name, (void*)this);
135                }
136        #endif
[b798713]137
[75f3522]138        {
[c81ebf9]139                // Setup preemption data
140                preemption_scope scope = { this };
141
[4069faad]142                __cfadbg_print_safe(runtime_core, "Kernel : core %p started\n", this);
[8118303]143
[ac2b598]144                $thread * readyThread = 0p;
[1eb239e4]145                MAIN_LOOP:
146                for() {
[92e7631]147                        // Try to get the next thread
[8c50aed]148                        readyThread = __next_thread( this->cltr );
[75f3522]149
[1eb239e4]150                        if( !readyThread ) {
151                                readyThread = __next_thread_slow( this->cltr );
152                        }
[4e6fb8e]153
[1eb239e4]154                        HALT:
155                        if( !readyThread ) {
156                                // Don't block if we are done
157                                if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
[c81ebf9]158
[1eb239e4]159                                #if !defined(__CFA_NO_STATISTICS__)
160                                        __tls_stats()->ready.sleep.halts++;
161                                #endif
[398e8e9]162
[1eb239e4]163                                // Push self to idle stack
164                                push(this->cltr->idles, * this);
[398e8e9]165
[1eb239e4]166                                // Confirm the ready-queue is empty
167                                readyThread = __next_thread_slow( this->cltr );
168                                if( readyThread ) {
169                                        // A thread was found, cancel the halt
170                                        remove(this->cltr->idles, * this);
171
172                                        #if !defined(__CFA_NO_STATISTICS__)
173                                                __tls_stats()->ready.sleep.cancels++;
174                                        #endif
175
176                                        // continue the mai loop
177                                        break HALT;
178                                }
179
180                                #if !defined(__CFA_NO_STATISTICS__)
181                                        if(this->print_halts) {
182                                                __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 0\n", this->id, rdtscl());
183                                        }
184                                #endif
185
186                                wait( this->idle );
187
188                                #if !defined(__CFA_NO_STATISTICS__)
189                                        if(this->print_halts) {
190                                                __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 1\n", this->id, rdtscl());
191                                        }
192                                #endif
193
194                                // We were woken up, remove self from idle
195                                remove(this->cltr->idles, * this);
196
197                                // DON'T just proceed, start looking again
198                                continue MAIN_LOOP;
[64a7146]199                        }
[1eb239e4]200
201                        /* paranoid */ verify( readyThread );
202
203                        // We found a thread run it
204                        __run_thread(this, readyThread);
205
206                        // Are we done?
207                        if( __atomic_load_n(&this->do_terminate, __ATOMIC_SEQ_CST) ) break MAIN_LOOP;
[c81ebf9]208                }
209
[4069faad]210                __cfadbg_print_safe(runtime_core, "Kernel : core %p stopping\n", this);
[c84e80a]211        }
[8118303]212
[4cedd9f]213        V( this->terminated );
[bdeba0b]214
[28d73c1]215        if(this == mainProcessor) {
[6a490b2]216                // HACK : the coroutine context switch expects this_thread to be set
217                // and it make sense for it to be set in all other cases except here
218                // fake it
219                kernelTLS.this_thread = mainThread;
220        }
[7768b8d]221
[4069faad]222        __cfadbg_print_safe(runtime_core, "Kernel : core %p terminated\n", this);
[c84e80a]223}
224
[5c1a531]225static int * __volatile_errno() __attribute__((noinline));
226static int * __volatile_errno() { asm(""); return &errno; }
227
[14a61b5]228// KERNEL ONLY
[1c273d0]229// runThread runs a thread by context switching
230// from the processor coroutine to the target thread
[ac2b598]231static void __run_thread(processor * this, $thread * thrd_dst) {
[1eb239e4]232        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
233        /* paranoid */ verifyf( thrd_dst->state == Ready || thrd_dst->preempted != __NO_PREEMPTION, "state : %d, preempted %d\n", thrd_dst->state, thrd_dst->preempted);
234        /* paranoid */ verifyf( thrd_dst->link.next == 0p, "Expected null got %p", thrd_dst->link.next );
235        __builtin_prefetch( thrd_dst->context.SP );
236
[ac2b598]237        $coroutine * proc_cor = get_coroutine(this->runner);
[8fcbb4c]238
[9f575ea]239        // set state of processor coroutine to inactive
240        verify(proc_cor->state == Active);
[ae7be7a]241        proc_cor->state = Blocked;
[e8e457e]242
[9f575ea]243        // Actually run the thread
[3381ed7]244        RUNNING:  while(true) {
[ff79d5e]245                thrd_dst->preempted = __NO_PREEMPTION;
246                thrd_dst->state = Active;
[e8e457e]247
[ae66348]248                __cfaabi_dbg_debug_do(
[276ae57e]249                        thrd_dst->park_stale   = true;
250                        thrd_dst->unpark_stale = true;
[ae66348]251                )
[58d64a4]252                // Update global state
253                kernelTLS.this_thread = thrd_dst;
[75f3522]254
[3381ed7]255                /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
[a7b486b]256                /* paranoid */ verify( kernelTLS.this_thread == thrd_dst );
[210b8b3]257                /* 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
258                /* 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
[3381ed7]259
[58d64a4]260
[9f575ea]261                // set context switch to the thread that the processor is executing
262                verify( thrd_dst->context.SP );
[c7a900a]263                __cfactx_switch( &proc_cor->context, &thrd_dst->context );
264                // when __cfactx_switch returns we are back in the processor coroutine
[9f575ea]265
[210b8b3]266                /* 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 );
267                /* 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 );
[a7b486b]268                /* paranoid */ verify( kernelTLS.this_thread == thrd_dst );
[3381ed7]269                /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
[75f3522]270
[58d64a4]271                // Reset global state
272                kernelTLS.this_thread = 0p;
[3381ed7]273
274                // We just finished running a thread, there are a few things that could have happened.
275                // 1 - Regular case : the thread has blocked and now one has scheduled it yet.
276                // 2 - Racy case    : the thread has blocked but someone has already tried to schedule it.
277                // 4 - Preempted
278                // In case 1, we may have won a race so we can't write to the state again.
279                // In case 2, we lost the race so we now own the thread.
280
281                if(unlikely(thrd_dst->preempted != __NO_PREEMPTION)) {
282                        // The thread was preempted, reschedule it and reset the flag
[9b1dcc2]283                        __schedule_thread( (__processor_id_t*)this, thrd_dst );
[3381ed7]284                        break RUNNING;
285                }
[75f3522]286
[ff79d5e]287                if(unlikely(thrd_dst->state == Halted)) {
288                        // The thread has halted, it should never be scheduled/run again
289                        // We may need to wake someone up here since
290                        unpark( this->destroyer __cfaabi_dbg_ctx2 );
291                        this->destroyer = 0p;
292                        break RUNNING;
293                }
294
295                /* paranoid */ verify( thrd_dst->state == Active );
296                thrd_dst->state = Blocked;
297
[3381ed7]298                // set state of processor coroutine to active and the thread to inactive
[ff79d5e]299                int old_ticket = __atomic_fetch_sub(&thrd_dst->ticket, 1, __ATOMIC_SEQ_CST);
300                __cfaabi_dbg_debug_do( thrd_dst->park_result = old_ticket; )
301                switch(old_ticket) {
302                        case 1:
[3381ed7]303                                // This is case 1, the regular case, nothing more is needed
304                                break RUNNING;
[ff79d5e]305                        case 2:
[3381ed7]306                                // This is case 2, the racy case, someone tried to run this thread before it finished blocking
307                                // In this case, just run it again.
308                                continue RUNNING;
309                        default:
310                                // This makes no sense, something is wrong abort
[ff79d5e]311                                abort();
[3381ed7]312                }
[9f575ea]313        }
[e8e457e]314
[9f575ea]315        // Just before returning to the processor, set the processor coroutine to active
[e8e457e]316        proc_cor->state = Active;
[1eb239e4]317
318        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
[82c948c]319}
320
[14a61b5]321// KERNEL_ONLY
[b0c7419]322void returnToKernel() {
[3381ed7]323        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
[ac2b598]324        $coroutine * proc_cor = get_coroutine(kernelTLS.this_processor->runner);
325        $thread * thrd_src = kernelTLS.this_thread;
[e8e457e]326
[29cb302]327        #if !defined(__CFA_NO_STATISTICS__)
328                struct processor * last_proc = kernelTLS.this_processor;
329        #endif
330
[9f575ea]331        // Run the thread on this processor
332        {
333                int local_errno = *__volatile_errno();
334                #if defined( __i386 ) || defined( __x86_64 )
335                        __x87_store;
336                #endif
337                verify( proc_cor->context.SP );
[c7a900a]338                __cfactx_switch( &thrd_src->context, &proc_cor->context );
[9f575ea]339                #if defined( __i386 ) || defined( __x86_64 )
340                        __x87_load;
341                #endif
342                *__volatile_errno() = local_errno;
[8fcbb4c]343        }
[deca0f5]344
[29cb302]345        #if !defined(__CFA_NO_STATISTICS__)
346                if(last_proc != kernelTLS.this_processor) {
347                        __tls_stats()->ready.threads.migration++;
348                }
349        #endif
350
[3381ed7]351        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
[210b8b3]352        /* 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 );
353        /* 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 );
[c84e80a]354}
355
[8def349]356//-----------------------------------------------------------------------------
357// Scheduler routines
[14a61b5]358// KERNEL ONLY
[9b1dcc2]359void __schedule_thread( struct __processor_id_t * id, $thread * thrd ) {
[6a490b2]360        /* paranoid */ verify( thrd );
361        /* paranoid */ verify( thrd->state != Halted );
[9f575ea]362        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
[3381ed7]363        /* paranoid */ #if defined( __CFA_WITH_VERIFY__ )
[504a7dc]364        /* paranoid */  if( thrd->state == Blocked || thrd->state == Start ) assertf( thrd->preempted == __NO_PREEMPTION,
365                                        "Error inactive thread marked as preempted, state %d, preemption %d\n", thrd->state, thrd->preempted );
[ff79d5e]366        /* paranoid */  if( thrd->preempted != __NO_PREEMPTION ) assertf(thrd->state == Active,
[504a7dc]367                                        "Error preempted thread marked as not currently running, state %d, preemption %d\n", thrd->state, thrd->preempted );
[3381ed7]368        /* paranoid */ #endif
[6a490b2]369        /* paranoid */ verifyf( thrd->link.next == 0p, "Expected null got %p", thrd->link.next );
[9f575ea]370
[ae7be7a]371        if (thrd->preempted == __NO_PREEMPTION) thrd->state = Ready;
[6b4cdd3]372
[9b1dcc2]373        ready_schedule_lock  ( id );
[504a7dc]374                push( thrd->curr_cluster, thrd );
[1eb239e4]375                __wake_one(id, thrd->curr_cluster);
[9b1dcc2]376        ready_schedule_unlock( id );
[1c273d0]377
[9f575ea]378        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
[db6f06a]379}
380
[14a61b5]381// KERNEL ONLY
[1eb239e4]382static inline $thread * __next_thread(cluster * this) with( *this ) {
[3381ed7]383        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
[7768b8d]384
[9b1dcc2]385        ready_schedule_lock  ( (__processor_id_t*)kernelTLS.this_processor );
[1eb239e4]386                $thread * thrd = pop( this );
[9b1dcc2]387        ready_schedule_unlock( (__processor_id_t*)kernelTLS.this_processor );
[7768b8d]388
[3381ed7]389        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
[1eb239e4]390        return thrd;
[eb2e723]391}
392
[64a7146]393// KERNEL ONLY
[1eb239e4]394static inline $thread * __next_thread_slow(cluster * this) with( *this ) {
[64a7146]395        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
396
397        ready_schedule_lock  ( (__processor_id_t*)kernelTLS.this_processor );
[1eb239e4]398                $thread * thrd = pop_slow( this );
[64a7146]399        ready_schedule_unlock( (__processor_id_t*)kernelTLS.this_processor );
400
401        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
[1eb239e4]402        return thrd;
[64a7146]403}
404
[2d8f7b0]405// KERNEL ONLY unpark with out disabling interrupts
[9b1dcc2]406void __unpark(  struct __processor_id_t * id, $thread * thrd __cfaabi_dbg_ctx_param2 ) {
[ae66348]407        // record activity
408        __cfaabi_dbg_record_thrd( *thrd, false, caller );
409
[ff79d5e]410        int old_ticket = __atomic_fetch_add(&thrd->ticket, 1, __ATOMIC_SEQ_CST);
411        __cfaabi_dbg_debug_do( thrd->unpark_result = old_ticket; thrd->unpark_state = thrd->state; )
412        switch(old_ticket) {
413                case 1:
[3381ed7]414                        // Wake won the race, the thread will reschedule/rerun itself
415                        break;
[ff79d5e]416                case 0:
[3381ed7]417                        /* paranoid */ verify( ! thrd->preempted != __NO_PREEMPTION );
[ff79d5e]418                        /* paranoid */ verify( thrd->state == Blocked );
[0b33412]419
[3381ed7]420                        // Wake lost the race,
[9b1dcc2]421                        __schedule_thread( id, thrd );
[3381ed7]422                        break;
423                default:
424                        // This makes no sense, something is wrong abort
425                        abort();
[de6319f]426        }
[db6f06a]427}
428
[2d8f7b0]429void unpark( $thread * thrd __cfaabi_dbg_ctx_param2 ) {
430        if( !thrd ) return;
[db6f06a]431
[82ff5845]432        disable_interrupts();
[9b1dcc2]433        __unpark( (__processor_id_t*)kernelTLS.this_processor, thrd __cfaabi_dbg_ctx_fwd2 );
[36982fc]434        enable_interrupts( __cfaabi_dbg_ctx );
[eb2e723]435}
436
[ae66348]437void park( __cfaabi_dbg_ctx_param ) {
[3381ed7]438        /* paranoid */ verify( kernelTLS.preemption_state.enabled );
[82ff5845]439        disable_interrupts();
[3381ed7]440        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
441        /* paranoid */ verify( kernelTLS.this_thread->preempted == __NO_PREEMPTION );
[0b33412]442
[ae66348]443        // record activity
444        __cfaabi_dbg_record_thrd( *kernelTLS.this_thread, true, caller );
[0b33412]445
[82c948c]446        returnToKernel();
[0b33412]447
[3381ed7]448        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
[36982fc]449        enable_interrupts( __cfaabi_dbg_ctx );
[3381ed7]450        /* paranoid */ verify( kernelTLS.preemption_state.enabled );
[0c78741]451
452}
[09800e9]453
[3381ed7]454// KERNEL ONLY
[b0c7419]455void __leave_thread() {
[3381ed7]456        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
[09800e9]457        returnToKernel();
[b0c7419]458        abort();
[09800e9]459}
460
[14a61b5]461// KERNEL ONLY
[3381ed7]462bool force_yield( __Preemption_Reason reason ) {
463        /* paranoid */ verify( kernelTLS.preemption_state.enabled );
[09800e9]464        disable_interrupts();
[3381ed7]465        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
[09800e9]466
[ac2b598]467        $thread * thrd = kernelTLS.this_thread;
[ff79d5e]468        /* paranoid */ verify(thrd->state == Active);
[3381ed7]469
470        // SKULLDUGGERY: It is possible that we are preempting this thread just before
471        // it was going to park itself. If that is the case and it is already using the
472        // intrusive fields then we can't use them to preempt the thread
473        // If that is the case, abandon the preemption.
474        bool preempted = false;
[504a7dc]475        if(thrd->link.next == 0p) {
[3381ed7]476                preempted = true;
477                thrd->preempted = reason;
478                returnToKernel();
[de6319f]479        }
[f2b12406]480
[3381ed7]481        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
482        enable_interrupts_noPoll();
483        /* paranoid */ verify( kernelTLS.preemption_state.enabled );
[f2b12406]484
[3381ed7]485        return preempted;
[f2b12406]486}
487
[14a61b5]488//=============================================================================================
[92e7631]489// Kernel Idle Sleep
[14a61b5]490//=============================================================================================
[64a7146]491// Wake a thread from the front if there are any
[1eb239e4]492static void __wake_one(struct __processor_id_t * id, cluster * this) {
493        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
[64a7146]494        /* paranoid */ verify( ready_schedule_islocked( id ) );
[14a61b5]495
[64a7146]496        // Check if there is a sleeping processor
[1eb239e4]497        processor * p;
498        unsigned idle;
499        unsigned total;
500        [idle, total, p] = query(this->idles);
[14a61b5]501
[64a7146]502        // If no one is sleeping, we are done
[1eb239e4]503        if( idle == 0 ) return;
[14a61b5]504
[64a7146]505        // We found a processor, wake it up
506        post( p->idle );
[14a61b5]507
[1eb239e4]508        #if !defined(__CFA_NO_STATISTICS__)
509                __tls_stats()->ready.sleep.wakes++;
510        #endif
511
512        /* paranoid */ verify( ready_schedule_islocked( id ) );
513        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
514
515        return;
[64a7146]516}
[14a61b5]517
[64a7146]518// Unconditionnaly wake a thread
[1eb239e4]519void __wake_proc(processor * this) {
[64a7146]520        __cfadbg_print_safe(runtime_core, "Kernel : waking Processor %p\n", this);
[14a61b5]521
[64a7146]522        disable_interrupts();
523                /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
[58d64a4]524                post( this->idle );
[64a7146]525        enable_interrupts( __cfaabi_dbg_ctx );
[92e7631]526}
527
[1eb239e4]528static void push  (__cluster_idles & this, processor & proc) {
529        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
530        lock( this );
531                this.idle++;
532                /* paranoid */ verify( this.idle <= this.total );
[8e16177]533
[1eb239e4]534                insert_first(this.list, proc);
535        unlock( this );
536        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
537}
[8e16177]538
[1eb239e4]539static void remove(__cluster_idles & this, processor & proc) {
540        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
541        lock( this );
542                this.idle--;
543                /* paranoid */ verify( this.idle >= 0 );
[c34ebf2]544
[1eb239e4]545                remove(proc);
546        unlock( this );
547        /* paranoid */ verify( ! kernelTLS.preemption_state.enabled );
548}
[c34ebf2]549
[1eb239e4]550static [unsigned idle, unsigned total, * processor] query( & __cluster_idles this ) {
551        for() {
552                uint64_t l = __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST);
553                if( 1 == (l % 2) ) { Pause(); continue; }
554                unsigned idle    = this.idle;
555                unsigned total   = this.total;
556                processor * proc = &this.list`first;
[7fdae38]557                // Compiler fence is unnecessary, but gcc-8 and older incorrectly reorder code without it
558                asm volatile("": : :"memory");
[1eb239e4]559                if(l != __atomic_load_n(&this.lock, __ATOMIC_SEQ_CST)) { Pause(); continue; }
560                return [idle, total, proc];
561        }
[6b4cdd3]562}
563
[dbe9b08]564//=============================================================================================
565// Unexpected Terminating logic
566//=============================================================================================
[ea7d2b0]567static __spinlock_t kernel_abort_lock;
[9d944b2]568static bool kernel_abort_called = false;
569
[afd550c]570void * kernel_abort(void) __attribute__ ((__nothrow__)) {
[9d944b2]571        // abort cannot be recursively entered by the same or different processors because all signal handlers return when
572        // the globalAbort flag is true.
[36982fc]573        lock( kernel_abort_lock __cfaabi_dbg_ctx2 );
[9d944b2]574
575        // first task to abort ?
[de94a60]576        if ( kernel_abort_called ) {                    // not first task to abort ?
[ea7d2b0]577                unlock( kernel_abort_lock );
[1c273d0]578
[9d944b2]579                sigset_t mask;
580                sigemptyset( &mask );
[de94a60]581                sigaddset( &mask, SIGALRM );            // block SIGALRM signals
[8a13c47]582                sigaddset( &mask, SIGUSR1 );            // block SIGALRM signals
583                sigsuspend( &mask );                            // block the processor to prevent further damage during abort
584                _exit( EXIT_FAILURE );                          // if processor unblocks before it is killed, terminate it
[de94a60]585        }
586        else {
587                kernel_abort_called = true;
588                unlock( kernel_abort_lock );
[9d944b2]589        }
590
[14a61b5]591        return kernelTLS.this_thread;
[9d944b2]592}
593
594void kernel_abort_msg( void * kernel_data, char * abort_text, int abort_text_size ) {
[b81fd95]595        $thread * thrd = ( $thread * ) kernel_data;
[9d944b2]596
[de94a60]597        if(thrd) {
598                int len = snprintf( abort_text, abort_text_size, "Error occurred while executing thread %.256s (%p)", thrd->self_cor.name, thrd );
[1c40091]599                __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[de94a60]600
[212c2187]601                if ( &thrd->self_cor != thrd->curr_cor ) {
602                        len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", thrd->curr_cor->name, thrd->curr_cor );
[1c40091]603                        __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[de94a60]604                }
605                else {
[1c40091]606                        __cfaabi_bits_write( STDERR_FILENO, ".\n", 2 );
[de94a60]607                }
[1c273d0]608        }
[9d944b2]609        else {
[de94a60]610                int len = snprintf( abort_text, abort_text_size, "Error occurred outside of any thread.\n" );
[1c40091]611                __cfaabi_bits_write( STDERR_FILENO, abort_text, len );
[9d944b2]612        }
613}
614
[2b8bc41]615int kernel_abort_lastframe( void ) __attribute__ ((__nothrow__)) {
[14a61b5]616        return get_coroutine(kernelTLS.this_thread) == get_coroutine(mainThread) ? 4 : 2;
[2b8bc41]617}
618
[de94a60]619static __spinlock_t kernel_debug_lock;
620
[9d944b2]621extern "C" {
[1c40091]622        void __cfaabi_bits_acquire() {
[36982fc]623                lock( kernel_debug_lock __cfaabi_dbg_ctx2 );
[9d944b2]624        }
625
[1c40091]626        void __cfaabi_bits_release() {
[ea7d2b0]627                unlock( kernel_debug_lock );
[9d944b2]628        }
[8118303]629}
630
[fa21ac9]631//=============================================================================================
632// Kernel Utilities
633//=============================================================================================
[bd98b58]634//-----------------------------------------------------------------------------
635// Locks
[242a902]636void  ?{}( semaphore & this, int count = 1 ) {
637        (this.lock){};
638        this.count = count;
639        (this.waiting){};
[db6f06a]640}
[242a902]641void ^?{}(semaphore & this) {}
[db6f06a]642
[71c8b7e]643bool P(semaphore & this) with( this ){
[65deb18]644        lock( lock __cfaabi_dbg_ctx2 );
645        count -= 1;
646        if ( count < 0 ) {
[bdeba0b]647                // queue current task
[14a61b5]648                append( waiting, kernelTLS.this_thread );
[bdeba0b]649
650                // atomically release spin lock and block
[3381ed7]651                unlock( lock );
[ae66348]652                park( __cfaabi_dbg_ctx );
[71c8b7e]653                return true;
[8def349]654        }
[4e6fb8e]655        else {
[65deb18]656            unlock( lock );
[71c8b7e]657            return false;
[4e6fb8e]658        }
[bd98b58]659}
660
[f0ce5f4]661bool V(semaphore & this) with( this ) {
[ac2b598]662        $thread * thrd = 0p;
[65deb18]663        lock( lock __cfaabi_dbg_ctx2 );
664        count += 1;
665        if ( count <= 0 ) {
[bdeba0b]666                // remove task at head of waiting list
[65deb18]667                thrd = pop_head( waiting );
[bd98b58]668        }
[bdeba0b]669
[65deb18]670        unlock( lock );
[bdeba0b]671
672        // make new owner
[ae66348]673        unpark( thrd __cfaabi_dbg_ctx2 );
[f0ce5f4]674
[d384787]675        return thrd != 0p;
676}
677
678bool V(semaphore & this, unsigned diff) with( this ) {
679        $thread * thrd = 0p;
680        lock( lock __cfaabi_dbg_ctx2 );
681        int release = max(-count, (int)diff);
682        count += diff;
683        for(release) {
684                unpark( pop_head( waiting ) __cfaabi_dbg_ctx2 );
685        }
686
687        unlock( lock );
688
[f0ce5f4]689        return thrd != 0p;
[bd98b58]690}
691
[de94a60]692//-----------------------------------------------------------------------------
693// Debug
694__cfaabi_dbg_debug_do(
[1997b4e]695        extern "C" {
[ae66348]696                void __cfaabi_dbg_record_lock(__spinlock_t & this, const char prev_name[]) {
[1997b4e]697                        this.prev_name = prev_name;
698                        this.prev_thrd = kernelTLS.this_thread;
699                }
[ae66348]700
701                void __cfaabi_dbg_record_thrd($thread & this, bool park, const char prev_name[]) {
702                        if(park) {
[f0ce5f4]703                                this.park_caller   = prev_name;
704                                this.park_stale    = false;
[ae66348]705                        }
706                        else {
[f0ce5f4]707                                this.unpark_caller = prev_name;
708                                this.unpark_stale  = false;
[ae66348]709                        }
710                }
[9181f1d]711        }
[f7d6bb0]712)
[2026bb6]713
714//-----------------------------------------------------------------------------
715// Debug
[8c50aed]716bool threading_enabled(void) __attribute__((const)) {
[2026bb6]717        return true;
718}
[c34ebf2]719
720//-----------------------------------------------------------------------------
721// Statistics
722#if !defined(__CFA_NO_STATISTICS__)
723        void print_halts( processor & this ) {
724                this.print_halts = true;
725        }
726#endif
[8118303]727// Local Variables: //
728// mode: c //
729// tab-width: 4 //
730// End: //
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