mirror of
https://github.com/Atmosphere-NX/Atmosphere.git
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96f95b9f95
* result: try out some experimental shenanigans * result: sketch out some more shenanigans * result: see what it looks like to convert kernel to use result conds instead of guards * make rest of kernel use experimental new macro-ing
280 lines
11 KiB
C++
280 lines
11 KiB
C++
/*
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* Copyright (c) Atmosphère-NX
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <mesosphere.hpp>
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namespace ams::kern {
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namespace {
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ALWAYS_INLINE bool ReadFromUser(u32 *out, KProcessAddress address) {
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return UserspaceAccess::CopyMemoryFromUserSize32Bit(out, GetVoidPointer(address));
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}
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ALWAYS_INLINE bool WriteToUser(KProcessAddress address, const u32 *p) {
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return UserspaceAccess::CopyMemoryToUserSize32Bit(GetVoidPointer(address), p);
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}
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ALWAYS_INLINE bool UpdateLockAtomic(u32 *out, KProcessAddress address, u32 if_zero, u32 new_orr_mask) {
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return UserspaceAccess::UpdateLockAtomic(out, GetPointer<u32>(address), if_zero, new_orr_mask);
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}
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class ThreadQueueImplForKConditionVariableWaitForAddress final : public KThreadQueue {
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public:
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constexpr ThreadQueueImplForKConditionVariableWaitForAddress() : KThreadQueue() { /* ... */ }
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virtual void CancelWait(KThread *waiting_thread, Result wait_result, bool cancel_timer_task) override {
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/* Remove the thread as a waiter from its owner. */
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waiting_thread->GetLockOwner()->RemoveWaiter(waiting_thread);
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/* Invoke the base cancel wait handler. */
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KThreadQueue::CancelWait(waiting_thread, wait_result, cancel_timer_task);
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}
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};
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class ThreadQueueImplForKConditionVariableWaitConditionVariable final : public KThreadQueue {
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private:
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KConditionVariable::ThreadTree *m_tree;
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public:
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constexpr ThreadQueueImplForKConditionVariableWaitConditionVariable(KConditionVariable::ThreadTree *t) : KThreadQueue(), m_tree(t) { /* ... */ }
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virtual void CancelWait(KThread *waiting_thread, Result wait_result, bool cancel_timer_task) override {
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/* Remove the thread as a waiter from its owner. */
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if (KThread *owner = waiting_thread->GetLockOwner(); owner != nullptr) {
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owner->RemoveWaiter(waiting_thread);
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}
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/* If the thread is waiting on a condvar, remove it from the tree. */
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if (waiting_thread->IsWaitingForConditionVariable()) {
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m_tree->erase(m_tree->iterator_to(*waiting_thread));
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waiting_thread->ClearConditionVariable();
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}
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/* Invoke the base cancel wait handler. */
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KThreadQueue::CancelWait(waiting_thread, wait_result, cancel_timer_task);
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}
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};
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}
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Result KConditionVariable::SignalToAddress(KProcessAddress addr) {
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KThread *owner_thread = GetCurrentThreadPointer();
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/* Signal the address. */
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{
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KScopedSchedulerLock sl;
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/* Remove waiter thread. */
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s32 num_waiters;
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KThread *next_owner_thread = owner_thread->RemoveWaiterByKey(std::addressof(num_waiters), addr);
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/* Determine the next tag. */
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u32 next_value = 0;
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if (next_owner_thread != nullptr) {
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next_value = next_owner_thread->GetAddressKeyValue();
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if (num_waiters > 1) {
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next_value |= ams::svc::HandleWaitMask;
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}
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/* Write the value to userspace. */
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Result result;
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if (AMS_LIKELY(WriteToUser(addr, std::addressof(next_value)))) {
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result = ResultSuccess();
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} else {
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result = svc::ResultInvalidCurrentMemory();
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}
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/* Signal the next owner thread. */
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next_owner_thread->EndWait(result);
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R_RETURN(result);
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} else {
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/* Just write the value to userspace. */
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R_UNLESS(WriteToUser(addr, std::addressof(next_value)), svc::ResultInvalidCurrentMemory());
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R_SUCCEED();
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}
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}
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}
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Result KConditionVariable::WaitForAddress(ams::svc::Handle handle, KProcessAddress addr, u32 value) {
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KThread *cur_thread = GetCurrentThreadPointer();
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ThreadQueueImplForKConditionVariableWaitForAddress wait_queue;
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/* Wait for the address. */
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KThread *owner_thread;
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{
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KScopedSchedulerLock sl;
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/* Check if the thread should terminate. */
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R_UNLESS(!cur_thread->IsTerminationRequested(), svc::ResultTerminationRequested());
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/* Read the tag from userspace. */
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u32 test_tag;
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R_UNLESS(ReadFromUser(std::addressof(test_tag), addr), svc::ResultInvalidCurrentMemory());
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/* If the tag isn't the handle (with wait mask), we're done. */
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R_SUCCEED_IF(test_tag != (handle | ams::svc::HandleWaitMask));
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/* Get the lock owner thread. */
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owner_thread = GetCurrentProcess().GetHandleTable().GetObjectWithoutPseudoHandle<KThread>(handle).ReleasePointerUnsafe();
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R_UNLESS(owner_thread != nullptr, svc::ResultInvalidHandle());
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/* Update the lock. */
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cur_thread->SetAddressKey(addr, value);
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owner_thread->AddWaiter(cur_thread);
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/* Begin waiting. */
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cur_thread->BeginWait(std::addressof(wait_queue));
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}
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/* Close our reference to the owner thread, now that the wait is over. */
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owner_thread->Close();
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/* Get the wait result. */
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R_RETURN(cur_thread->GetWaitResult());
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}
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void KConditionVariable::SignalImpl(KThread *thread) {
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/* Check pre-conditions. */
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MESOSPHERE_ASSERT(KScheduler::IsSchedulerLockedByCurrentThread());
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/* Update the tag. */
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KProcessAddress address = thread->GetAddressKey();
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u32 own_tag = thread->GetAddressKeyValue();
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u32 prev_tag;
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bool can_access;
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{
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KScopedInterruptDisable di;
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can_access = cpu::CanAccessAtomic(address);
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if (AMS_LIKELY(can_access)) {
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can_access = UpdateLockAtomic(std::addressof(prev_tag), address, own_tag, ams::svc::HandleWaitMask);
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}
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}
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if (AMS_LIKELY(can_access)) {
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if (prev_tag == ams::svc::InvalidHandle) {
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/* If nobody held the lock previously, we're all good. */
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thread->EndWait(ResultSuccess());
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} else {
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/* Get the previous owner. */
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KThread *owner_thread = GetCurrentProcess().GetHandleTable().GetObjectWithoutPseudoHandle<KThread>(static_cast<ams::svc::Handle>(prev_tag & ~ams::svc::HandleWaitMask))
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.ReleasePointerUnsafe();
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if (AMS_LIKELY(owner_thread != nullptr)) {
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/* Add the thread as a waiter on the owner. */
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owner_thread->AddWaiter(thread);
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owner_thread->Close();
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} else {
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/* The lock was tagged with a thread that doesn't exist. */
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thread->EndWait(svc::ResultInvalidState());
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}
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}
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} else {
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/* If the address wasn't accessible, note so. */
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thread->EndWait(svc::ResultInvalidCurrentMemory());
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}
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}
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void KConditionVariable::Signal(uintptr_t cv_key, s32 count) {
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/* Perform signaling. */
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int num_waiters = 0;
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{
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KScopedSchedulerLock sl;
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auto it = m_tree.nfind_key({ cv_key, -1 });
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while ((it != m_tree.end()) && (count <= 0 || num_waiters < count) && (it->GetConditionVariableKey() == cv_key)) {
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KThread *target_thread = std::addressof(*it);
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this->SignalImpl(target_thread);
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it = m_tree.erase(it);
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target_thread->ClearConditionVariable();
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++num_waiters;
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}
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/* If we have no waiters, clear the has waiter flag. */
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if (it == m_tree.end() || it->GetConditionVariableKey() != cv_key) {
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const u32 has_waiter_flag = 0;
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WriteToUser(cv_key, std::addressof(has_waiter_flag));
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}
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}
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}
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Result KConditionVariable::Wait(KProcessAddress addr, uintptr_t key, u32 value, s64 timeout) {
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/* Prepare to wait. */
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KThread *cur_thread = GetCurrentThreadPointer();
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KHardwareTimer *timer;
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ThreadQueueImplForKConditionVariableWaitConditionVariable wait_queue(std::addressof(m_tree));
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{
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KScopedSchedulerLockAndSleep slp(std::addressof(timer), cur_thread, timeout);
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/* Check that the thread isn't terminating. */
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if (cur_thread->IsTerminationRequested()) {
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slp.CancelSleep();
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R_THROW(svc::ResultTerminationRequested());
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}
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/* Update the value and process for the next owner. */
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{
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/* Remove waiter thread. */
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s32 num_waiters;
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KThread *next_owner_thread = cur_thread->RemoveWaiterByKey(std::addressof(num_waiters), GetInteger(addr));
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/* Update for the next owner thread. */
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u32 next_value = 0;
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if (next_owner_thread != nullptr) {
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/* Get the next tag value. */
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next_value = next_owner_thread->GetAddressKeyValue();
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if (num_waiters > 1) {
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next_value |= ams::svc::HandleWaitMask;
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}
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/* Wake up the next owner. */
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next_owner_thread->EndWait(ResultSuccess());
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}
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/* Write to the cv key. */
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{
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const u32 has_waiter_flag = 1;
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WriteToUser(key, std::addressof(has_waiter_flag));
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cpu::DataMemoryBarrierInnerShareable();
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}
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/* Write the value to userspace. */
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if (!WriteToUser(addr, std::addressof(next_value))) {
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slp.CancelSleep();
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R_THROW(svc::ResultInvalidCurrentMemory());
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}
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}
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/* If timeout is zero, time out. */
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R_UNLESS(timeout != 0, svc::ResultTimedOut());
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/* Update condition variable tracking. */
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cur_thread->SetConditionVariable(std::addressof(m_tree), addr, key, value);
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m_tree.insert(*cur_thread);
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/* Begin waiting. */
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wait_queue.SetHardwareTimer(timer);
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cur_thread->BeginWait(std::addressof(wait_queue));
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}
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/* Get the wait result. */
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R_RETURN(cur_thread->GetWaitResult());
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}
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}
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