diff options
Diffstat (limited to 'src/core/hle/kernel/k_condition_variable.cpp')
-rw-r--r-- | src/core/hle/kernel/k_condition_variable.cpp | 345 |
1 files changed, 345 insertions, 0 deletions
diff --git a/src/core/hle/kernel/k_condition_variable.cpp b/src/core/hle/kernel/k_condition_variable.cpp new file mode 100644 index 000000000..170d8fa0d --- /dev/null +++ b/src/core/hle/kernel/k_condition_variable.cpp @@ -0,0 +1,345 @@ +// Copyright 2021 yuzu Emulator Project +// Licensed under GPLv2 or any later version +// Refer to the license.txt file included. + +#include <vector> + +#include "core/arm/exclusive_monitor.h" +#include "core/core.h" +#include "core/hle/kernel/k_condition_variable.h" +#include "core/hle/kernel/k_scheduler.h" +#include "core/hle/kernel/k_scoped_scheduler_lock_and_sleep.h" +#include "core/hle/kernel/k_synchronization_object.h" +#include "core/hle/kernel/k_thread.h" +#include "core/hle/kernel/kernel.h" +#include "core/hle/kernel/process.h" +#include "core/hle/kernel/svc_common.h" +#include "core/hle/kernel/svc_results.h" +#include "core/memory.h" + +namespace Kernel { + +namespace { + +bool ReadFromUser(Core::System& system, u32* out, VAddr address) { + *out = system.Memory().Read32(address); + return true; +} + +bool WriteToUser(Core::System& system, VAddr address, const u32* p) { + system.Memory().Write32(address, *p); + return true; +} + +bool UpdateLockAtomic(Core::System& system, u32* out, VAddr address, u32 if_zero, + u32 new_orr_mask) { + auto& monitor = system.Monitor(); + const auto current_core = system.CurrentCoreIndex(); + + // Load the value from the address. + const auto expected = monitor.ExclusiveRead32(current_core, address); + + // Orr in the new mask. + u32 value = expected | new_orr_mask; + + // If the value is zero, use the if_zero value, otherwise use the newly orr'd value. + if (!expected) { + value = if_zero; + } + + // Try to store. + if (!monitor.ExclusiveWrite32(current_core, address, value)) { + // If we failed to store, try again. + return UpdateLockAtomic(system, out, address, if_zero, new_orr_mask); + } + + // We're done. + *out = expected; + return true; +} + +} // namespace + +KConditionVariable::KConditionVariable(Core::System& system_) + : system{system_}, kernel{system.Kernel()} {} + +KConditionVariable::~KConditionVariable() = default; + +ResultCode KConditionVariable::SignalToAddress(VAddr addr) { + KThread* owner_thread = kernel.CurrentScheduler()->GetCurrentThread(); + + // Signal the address. + { + KScopedSchedulerLock sl(kernel); + + // Remove waiter thread. + s32 num_waiters{}; + KThread* next_owner_thread = + owner_thread->RemoveWaiterByKey(std::addressof(num_waiters), addr); + + // Determine the next tag. + u32 next_value{}; + if (next_owner_thread) { + next_value = next_owner_thread->GetAddressKeyValue(); + if (num_waiters > 1) { + next_value |= Svc::HandleWaitMask; + } + + next_owner_thread->SetSyncedObject(nullptr, RESULT_SUCCESS); + next_owner_thread->Wakeup(); + } + + // Write the value to userspace. + if (!WriteToUser(system, addr, std::addressof(next_value))) { + if (next_owner_thread) { + next_owner_thread->SetSyncedObject(nullptr, ResultInvalidCurrentMemory); + } + + return ResultInvalidCurrentMemory; + } + } + + return RESULT_SUCCESS; +} + +ResultCode KConditionVariable::WaitForAddress(Handle handle, VAddr addr, u32 value) { + KThread* cur_thread = kernel.CurrentScheduler()->GetCurrentThread(); + + // Wait for the address. + { + std::shared_ptr<KThread> owner_thread; + ASSERT(!owner_thread); + { + KScopedSchedulerLock sl(kernel); + cur_thread->SetSyncedObject(nullptr, RESULT_SUCCESS); + + // Check if the thread should terminate. + R_UNLESS(!cur_thread->IsTerminationRequested(), ResultTerminationRequested); + + { + // Read the tag from userspace. + u32 test_tag{}; + R_UNLESS(ReadFromUser(system, std::addressof(test_tag), addr), + ResultInvalidCurrentMemory); + + // If the tag isn't the handle (with wait mask), we're done. + R_UNLESS(test_tag == (handle | Svc::HandleWaitMask), RESULT_SUCCESS); + + // Get the lock owner thread. + owner_thread = kernel.CurrentProcess()->GetHandleTable().Get<KThread>(handle); + R_UNLESS(owner_thread, ResultInvalidHandle); + + // Update the lock. + cur_thread->SetAddressKey(addr, value); + owner_thread->AddWaiter(cur_thread); + cur_thread->SetState(ThreadState::Waiting); + cur_thread->SetWaitReasonForDebugging(ThreadWaitReasonForDebugging::ConditionVar); + cur_thread->SetMutexWaitAddressForDebugging(addr); + } + } + ASSERT(owner_thread); + } + + // Remove the thread as a waiter from the lock owner. + { + KScopedSchedulerLock sl(kernel); + KThread* owner_thread = cur_thread->GetLockOwner(); + if (owner_thread != nullptr) { + owner_thread->RemoveWaiter(cur_thread); + } + } + + // Get the wait result. + KSynchronizationObject* dummy{}; + return cur_thread->GetWaitResult(std::addressof(dummy)); +} + +KThread* KConditionVariable::SignalImpl(KThread* thread) { + // Check pre-conditions. + ASSERT(kernel.GlobalSchedulerContext().IsLocked()); + + // Update the tag. + VAddr address = thread->GetAddressKey(); + u32 own_tag = thread->GetAddressKeyValue(); + + u32 prev_tag{}; + bool can_access{}; + { + // TODO(bunnei): We should disable interrupts here via KScopedInterruptDisable. + // TODO(bunnei): We should call CanAccessAtomic(..) here. + can_access = true; + if (can_access) { + UpdateLockAtomic(system, std::addressof(prev_tag), address, own_tag, + Svc::HandleWaitMask); + } + } + + KThread* thread_to_close = nullptr; + if (can_access) { + if (prev_tag == InvalidHandle) { + // If nobody held the lock previously, we're all good. + thread->SetSyncedObject(nullptr, RESULT_SUCCESS); + thread->Wakeup(); + } else { + // Get the previous owner. + auto owner_thread = kernel.CurrentProcess()->GetHandleTable().Get<KThread>( + prev_tag & ~Svc::HandleWaitMask); + + if (owner_thread) { + // Add the thread as a waiter on the owner. + owner_thread->AddWaiter(thread); + thread_to_close = owner_thread.get(); + } else { + // The lock was tagged with a thread that doesn't exist. + thread->SetSyncedObject(nullptr, ResultInvalidState); + thread->Wakeup(); + } + } + } else { + // If the address wasn't accessible, note so. + thread->SetSyncedObject(nullptr, ResultInvalidCurrentMemory); + thread->Wakeup(); + } + + return thread_to_close; +} + +void KConditionVariable::Signal(u64 cv_key, s32 count) { + // Prepare for signaling. + constexpr int MaxThreads = 16; + + // TODO(bunnei): This should just be Thread once we implement KAutoObject instead of using + // std::shared_ptr. + std::vector<std::shared_ptr<KThread>> thread_list; + std::array<KThread*, MaxThreads> thread_array; + s32 num_to_close{}; + + // Perform signaling. + s32 num_waiters{}; + { + KScopedSchedulerLock sl(kernel); + + auto it = thread_tree.nfind_light({cv_key, -1}); + while ((it != thread_tree.end()) && (count <= 0 || num_waiters < count) && + (it->GetConditionVariableKey() == cv_key)) { + KThread* target_thread = std::addressof(*it); + + if (KThread* thread = SignalImpl(target_thread); thread != nullptr) { + if (num_to_close < MaxThreads) { + thread_array[num_to_close++] = thread; + } else { + thread_list.push_back(SharedFrom(thread)); + } + } + + it = thread_tree.erase(it); + target_thread->ClearConditionVariable(); + ++num_waiters; + } + + // If we have no waiters, clear the has waiter flag. + if (it == thread_tree.end() || it->GetConditionVariableKey() != cv_key) { + const u32 has_waiter_flag{}; + WriteToUser(system, cv_key, std::addressof(has_waiter_flag)); + } + } + + // Close threads in the array. + for (auto i = 0; i < num_to_close; ++i) { + thread_array[i]->Close(); + } + + // Close threads in the list. + for (auto it = thread_list.begin(); it != thread_list.end(); it = thread_list.erase(it)) { + (*it)->Close(); + } +} + +ResultCode KConditionVariable::Wait(VAddr addr, u64 key, u32 value, s64 timeout) { + // Prepare to wait. + KThread* cur_thread = kernel.CurrentScheduler()->GetCurrentThread(); + + { + KScopedSchedulerLockAndSleep slp{kernel, cur_thread, timeout}; + + // Set the synced object. + cur_thread->SetSyncedObject(nullptr, ResultTimedOut); + + // Check that the thread isn't terminating. + if (cur_thread->IsTerminationRequested()) { + slp.CancelSleep(); + return ResultTerminationRequested; + } + + // Update the value and process for the next owner. + { + // Remove waiter thread. + s32 num_waiters{}; + KThread* next_owner_thread = + cur_thread->RemoveWaiterByKey(std::addressof(num_waiters), addr); + + // Update for the next owner thread. + u32 next_value{}; + if (next_owner_thread != nullptr) { + // Get the next tag value. + next_value = next_owner_thread->GetAddressKeyValue(); + if (num_waiters > 1) { + next_value |= Svc::HandleWaitMask; + } + + // Wake up the next owner. + next_owner_thread->SetSyncedObject(nullptr, RESULT_SUCCESS); + next_owner_thread->Wakeup(); + } + + // Write to the cv key. + { + const u32 has_waiter_flag = 1; + WriteToUser(system, key, std::addressof(has_waiter_flag)); + // TODO(bunnei): We should call DataMemoryBarrier(..) here. + } + + // Write the value to userspace. + if (!WriteToUser(system, addr, std::addressof(next_value))) { + slp.CancelSleep(); + return ResultInvalidCurrentMemory; + } + } + + // Update condition variable tracking. + { + cur_thread->SetConditionVariable(std::addressof(thread_tree), addr, key, value); + thread_tree.insert(*cur_thread); + } + + // If the timeout is non-zero, set the thread as waiting. + if (timeout != 0) { + cur_thread->SetState(ThreadState::Waiting); + cur_thread->SetWaitReasonForDebugging(ThreadWaitReasonForDebugging::ConditionVar); + cur_thread->SetMutexWaitAddressForDebugging(addr); + } + } + + // Cancel the timer wait. + kernel.TimeManager().UnscheduleTimeEvent(cur_thread); + + // Remove from the condition variable. + { + KScopedSchedulerLock sl(kernel); + + if (KThread* owner = cur_thread->GetLockOwner(); owner != nullptr) { + owner->RemoveWaiter(cur_thread); + } + + if (cur_thread->IsWaitingForConditionVariable()) { + thread_tree.erase(thread_tree.iterator_to(*cur_thread)); + cur_thread->ClearConditionVariable(); + } + } + + // Get the result. + KSynchronizationObject* dummy{}; + return cur_thread->GetWaitResult(std::addressof(dummy)); +} + +} // namespace Kernel |