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Atmosphere/libraries/libmesosphere/source/kern_k_synchronization.cpp
2020-07-10 11:55:33 -07:00

139 lines
4.6 KiB
C++

/*
* Copyright (c) 2018-2020 Atmosphère-NX
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <mesosphere.hpp>
namespace ams::kern {
Result KSynchronization::Wait(s32 *out_index, KSynchronizationObject **objects, const s32 num_objects, s64 timeout) {
MESOSPHERE_ASSERT_THIS();
/* Allocate space on stack for thread iterators. */
KSynchronizationObject::iterator *thread_iters = static_cast<KSynchronizationObject::iterator *>(__builtin_alloca(sizeof(KSynchronizationObject::iterator) * num_objects));
/* Prepare for wait. */
KThread *thread = GetCurrentThreadPointer();
s32 sync_index = -1;
KHardwareTimer *timer;
{
/* Setup the scheduling lock and sleep. */
KScopedSchedulerLockAndSleep slp(std::addressof(timer), thread, timeout);
/* Check if any of the objects are already signaled. */
for (auto i = 0; i < num_objects; ++i) {
AMS_ASSERT(objects[i] != nullptr);
if (objects[i]->IsSignaled()) {
*out_index = i;
slp.CancelSleep();
return ResultSuccess();
}
}
/* Check if the timeout is zero. */
if (timeout == 0) {
slp.CancelSleep();
return svc::ResultTimedOut();
}
/* Check if the thread should terminate. */
if (thread->IsTerminationRequested()) {
slp.CancelSleep();
return svc::ResultTerminationRequested();
}
/* Check if waiting was canceled. */
if (thread->IsWaitCancelled()) {
slp.CancelSleep();
thread->ClearWaitCancelled();
return svc::ResultCancelled();
}
/* Add the waiters. */
for (auto i = 0; i < num_objects; ++i) {
thread_iters[i] = objects[i]->RegisterWaitingThread(thread);
}
/* Mark the thread as waiting. */
thread->SetCancellable();
thread->SetSyncedObject(nullptr, svc::ResultTimedOut());
thread->SetState(KThread::ThreadState_Waiting);
}
/* The lock/sleep is done, so we should be able to get our result. */
/* Thread is no longer cancellable. */
thread->ClearCancellable();
/* Cancel the timer as needed. */
if (timer != nullptr) {
timer->CancelTask(thread);
}
/* Get the wait result. */
Result wait_result;
{
KScopedSchedulerLock lk;
KSynchronizationObject *synced_obj;
wait_result = thread->GetWaitResult(std::addressof(synced_obj));
for (auto i = 0; i < num_objects; ++i) {
objects[i]->UnregisterWaitingThread(thread_iters[i]);
if (objects[i] == synced_obj) {
sync_index = i;
}
}
}
/* Set output. */
*out_index = sync_index;
return wait_result;
}
void KSynchronization::OnAvailable(KSynchronizationObject *object) {
MESOSPHERE_ASSERT_THIS();
KScopedSchedulerLock sl;
/* If we're not signaled, we've nothing to notify. */
if (!object->IsSignaled()) {
return;
}
/* Iterate over each thread. */
for (auto &thread : *object) {
if (thread.GetState() == KThread::ThreadState_Waiting) {
thread.SetSyncedObject(object, ResultSuccess());
thread.SetState(KThread::ThreadState_Runnable);
}
}
}
void KSynchronization::OnAbort(KSynchronizationObject *object, Result abort_reason) {
MESOSPHERE_ASSERT_THIS();
KScopedSchedulerLock sl;
/* Iterate over each thread. */
for (auto &thread : *object) {
if (thread.GetState() == KThread::ThreadState_Waiting) {
thread.SetSyncedObject(object, abort_reason);
thread.SetState(KThread::ThreadState_Runnable);
}
}
}
}