124 lines
3.2 KiB
C++
124 lines
3.2 KiB
C++
/*
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* Copyright (c) 2012, 2014 Jonas 'Sortie' Termansen.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* kthread.cpp
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* Utility and synchronization mechanisms for kernel threads.
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*/
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#include <sortix/signal.h>
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#include <sortix/kernel/kernel.h>
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#include <sortix/kernel/kthread.h>
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#include <sortix/kernel/scheduler.h>
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#include <sortix/kernel/signal.h>
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#include <sortix/kernel/thread.h>
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#include <sortix/kernel/worker.h>
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namespace Sortix {
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// The kernel thread needs another stack to delete its own stack.
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static void kthread_do_kill_thread(void* user)
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{
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Thread* thread = (Thread*) user;
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while ( thread->state != ThreadState::DEAD )
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kthread_yield();
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FreeThread(thread);
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}
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extern "C" void kthread_exit()
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{
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Worker::Schedule(kthread_do_kill_thread, CurrentThread());
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Scheduler::ExitThread();
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__builtin_unreachable();
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}
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struct kthread_cond_elem
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{
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kthread_cond_elem_t* next;
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volatile unsigned long woken;
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};
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extern "C" void kthread_cond_wait(kthread_cond_t* cond, kthread_mutex_t* mutex)
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{
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kthread_cond_elem_t elem;
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elem.next = NULL;
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elem.woken = 0;
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if ( cond->last ) { cond->last->next = &elem; }
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if ( !cond->last ) { cond->first = &elem; }
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cond->last = &elem;
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while ( !elem.woken )
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{
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kthread_mutex_unlock(mutex);
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Scheduler::Yield();
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kthread_mutex_lock(mutex);
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}
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}
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extern "C" unsigned long kthread_cond_wait_signal(kthread_cond_t* cond,
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kthread_mutex_t* mutex)
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{
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if ( Signal::IsPending() )
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return 0;
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kthread_cond_elem_t elem;
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elem.next = NULL;
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elem.woken = 0;
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if ( cond->last ) { cond->last->next = &elem; }
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if ( !cond->last ) { cond->first = &elem; }
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cond->last = &elem;
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while ( !elem.woken )
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{
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if ( Signal::IsPending() )
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{
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if ( cond->first == &elem )
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{
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cond->first = elem.next;
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if ( cond->last == &elem )
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cond->last = NULL;
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}
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else
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{
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kthread_cond_elem_t* prev = cond->first;
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while ( prev->next != &elem )
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prev = prev->next;
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prev->next = elem.next;
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if ( cond->last == &elem )
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cond->last = prev;
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}
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// Note that the thread still owns the mutex.
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return 0;
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}
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kthread_mutex_unlock(mutex);
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Scheduler::Yield();
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kthread_mutex_lock(mutex);
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}
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return 1;
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}
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extern "C" void kthread_cond_signal(kthread_cond_t* cond)
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{
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kthread_cond_elem_t* elem = cond->first;
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if ( !elem ) { return; }
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if ( !(cond->first = elem->next) ) { cond->last = NULL; }
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elem->next = NULL;
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elem->woken = 1;
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}
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extern "C" void kthread_cond_broadcast(kthread_cond_t* cond)
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{
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while ( cond->first ) { kthread_cond_signal(cond); }
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}
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} // namespace Sortix
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