kernel: Remove the Timer class

A holdover from citra, the Horizon kernel on the switch has no
prominent kernel object that functions as a timer. At least not
to the degree of sophistication that this class provided.

As such, this can be removed entirely. This class also wasn't used at
all in any meaningful way within the core, so this was just code sitting
around doing nothing. This also allows removing a few things from the
main KernelCore class that allows it to use slightly less resources
overall (though very minor and not anything really noticeable).

src/core/CMakeLists.txt

@@ -140,8 +140,6 @@ add_library(core STATIC
     hle/kernel/svc_wrap.h
     hle/kernel/thread.cpp
     hle/kernel/thread.h
-    hle/kernel/timer.cpp
-    hle/kernel/timer.h
     hle/kernel/vm_manager.cpp
     hle/kernel/vm_manager.h
     hle/kernel/wait_object.cpp

src/core/hle/kernel/kernel.cpp

@@ -18,7 +18,6 @@
 #include "core/hle/kernel/process.h"
 #include "core/hle/kernel/resource_limit.h"
 #include "core/hle/kernel/thread.h"
-#include "core/hle/kernel/timer.h"
 #include "core/hle/lock.h"
 #include "core/hle/result.h"
 
@@ -86,27 +85,12 @@ static void ThreadWakeupCallback(u64 thread_handle, [[maybe_unused]] int cycles_
     }
 }
 
-/// The timer callback event, called when a timer is fired
-static void TimerCallback(u64 timer_handle, int cycles_late) {
-    const auto proper_handle = static_cast<Handle>(timer_handle);
-    const auto& system = Core::System::GetInstance();
-    SharedPtr<Timer> timer = system.Kernel().RetrieveTimerFromCallbackHandleTable(proper_handle);
-
-    if (timer == nullptr) {
-        LOG_CRITICAL(Kernel, "Callback fired for invalid timer {:016X}", timer_handle);
-        return;
-    }
-
-    timer->Signal(cycles_late);
-}
-
 struct KernelCore::Impl {
     void Initialize(KernelCore& kernel) {
         Shutdown();
 
         InitializeSystemResourceLimit(kernel);
         InitializeThreads();
-        InitializeTimers();
     }
 
     void Shutdown() {
@@ -122,9 +106,6 @@ struct KernelCore::Impl {
         thread_wakeup_callback_handle_table.Clear();
         thread_wakeup_event_type = nullptr;
 
-        timer_callback_handle_table.Clear();
-        timer_callback_event_type = nullptr;
-
         named_ports.clear();
     }
 
@@ -146,11 +127,6 @@ struct KernelCore::Impl {
             CoreTiming::RegisterEvent("ThreadWakeupCallback", ThreadWakeupCallback);
     }
 
-    void InitializeTimers() {
-        timer_callback_handle_table.Clear();
-        timer_callback_event_type = CoreTiming::RegisterEvent("TimerCallback", TimerCallback);
-    }
-
     std::atomic<u32> next_object_id{0};
     std::atomic<u64> next_process_id{Process::ProcessIDMin};
     std::atomic<u64> next_thread_id{1};
@@ -161,12 +137,6 @@ struct KernelCore::Impl {
 
     SharedPtr<ResourceLimit> system_resource_limit;
 
-    /// The event type of the generic timer callback event
-    CoreTiming::EventType* timer_callback_event_type = nullptr;
-    // TODO(yuriks): This can be removed if Timer objects are explicitly pooled in the future,
-    // allowing us to simply use a pool index or similar.
-    Kernel::HandleTable timer_callback_handle_table;
-
     CoreTiming::EventType* thread_wakeup_event_type = nullptr;
     // TODO(yuriks): This can be removed if Thread objects are explicitly pooled in the future,
     // allowing us to simply use a pool index or similar.
@@ -198,10 +168,6 @@ SharedPtr<Thread> KernelCore::RetrieveThreadFromWakeupCallbackHandleTable(Handle
     return impl->thread_wakeup_callback_handle_table.Get<Thread>(handle);
 }
 
-SharedPtr<Timer> KernelCore::RetrieveTimerFromCallbackHandleTable(Handle handle) const {
-    return impl->timer_callback_handle_table.Get<Timer>(handle);
-}
-
 void KernelCore::AppendNewProcess(SharedPtr<Process> process) {
     impl->process_list.push_back(std::move(process));
 }
@@ -247,18 +213,10 @@ u64 KernelCore::CreateNewProcessID() {
     return impl->next_process_id++;
 }
 
-ResultVal<Handle> KernelCore::CreateTimerCallbackHandle(const SharedPtr<Timer>& timer) {
-    return impl->timer_callback_handle_table.Create(timer);
-}
-
 CoreTiming::EventType* KernelCore::ThreadWakeupCallbackEventType() const {
     return impl->thread_wakeup_event_type;
 }
 
-CoreTiming::EventType* KernelCore::TimerCallbackEventType() const {
-    return impl->timer_callback_event_type;
-}
-
 Kernel::HandleTable& KernelCore::ThreadWakeupCallbackHandleTable() {
     return impl->thread_wakeup_callback_handle_table;
 }

src/core/hle/kernel/kernel.h

@@ -22,7 +22,6 @@ class HandleTable;
 class Process;
 class ResourceLimit;
 class Thread;
-class Timer;
 
 /// Represents a single instance of the kernel.
 class KernelCore {
@@ -51,9 +50,6 @@ public:
     /// Retrieves a shared pointer to a Thread instance within the thread wakeup handle table.
     SharedPtr<Thread> RetrieveThreadFromWakeupCallbackHandleTable(Handle handle) const;
 
-    /// Retrieves a shared pointer to a Timer instance within the timer callback handle table.
-    SharedPtr<Timer> RetrieveTimerFromCallbackHandleTable(Handle handle) const;
-
     /// Adds the given shared pointer to an internal list of active processes.
     void AppendNewProcess(SharedPtr<Process> process);
 
@@ -82,7 +78,6 @@ private:
     friend class Object;
     friend class Process;
     friend class Thread;
-    friend class Timer;
 
     /// Creates a new object ID, incrementing the internal object ID counter.
     u32 CreateNewObjectID();
@@ -93,15 +88,9 @@ private:
     /// Creates a new thread ID, incrementing the internal thread ID counter.
     u64 CreateNewThreadID();
 
-    /// Creates a timer callback handle for the given timer.
-    ResultVal<Handle> CreateTimerCallbackHandle(const SharedPtr<Timer>& timer);
-
     /// Retrieves the event type used for thread wakeup callbacks.
     CoreTiming::EventType* ThreadWakeupCallbackEventType() const;
 
-    /// Retrieves the event type used for timer callbacks.
-    CoreTiming::EventType* TimerCallbackEventType() const;
-
     /// Provides a reference to the thread wakeup callback handle table.
     Kernel::HandleTable& ThreadWakeupCallbackHandleTable();
 

src/core/hle/kernel/object.cpp

@@ -16,7 +16,6 @@ bool Object::IsWaitable() const {
     case HandleType::ReadableEvent:
     case HandleType::Thread:
     case HandleType::Process:
-    case HandleType::Timer:
     case HandleType::ServerPort:
     case HandleType::ServerSession:
         return true;

src/core/hle/kernel/object.h

@@ -25,7 +25,6 @@ enum class HandleType : u32 {
     Thread,
     Process,
     AddressArbiter,
-    Timer,
     ResourceLimit,
     ClientPort,
     ServerPort,

src/core/hle/kernel/timer.cpp

@@ -1,84 +0,0 @@
-// Copyright 2015 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
-
-#include "common/assert.h"
-#include "common/logging/log.h"
-#include "core/core.h"
-#include "core/core_timing.h"
-#include "core/core_timing_util.h"
-#include "core/hle/kernel/handle_table.h"
-#include "core/hle/kernel/kernel.h"
-#include "core/hle/kernel/object.h"
-#include "core/hle/kernel/thread.h"
-#include "core/hle/kernel/timer.h"
-
-namespace Kernel {
-
-Timer::Timer(KernelCore& kernel) : WaitObject{kernel} {}
-Timer::~Timer() = default;
-
-SharedPtr<Timer> Timer::Create(KernelCore& kernel, ResetType reset_type, std::string name) {
-    SharedPtr<Timer> timer(new Timer(kernel));
-
-    timer->reset_type = reset_type;
-    timer->signaled = false;
-    timer->name = std::move(name);
-    timer->initial_delay = 0;
-    timer->interval_delay = 0;
-    timer->callback_handle = kernel.CreateTimerCallbackHandle(timer).Unwrap();
-
-    return timer;
-}
-
-bool Timer::ShouldWait(Thread* thread) const {
-    return !signaled;
-}
-
-void Timer::Acquire(Thread* thread) {
-    ASSERT_MSG(!ShouldWait(thread), "object unavailable!");
-
-    if (reset_type == ResetType::OneShot)
-        signaled = false;
-}
-
-void Timer::Set(s64 initial, s64 interval) {
-    // Ensure we get rid of any previous scheduled event
-    Cancel();
-
-    initial_delay = initial;
-    interval_delay = interval;
-
-    if (initial == 0) {
-        // Immediately invoke the callback
-        Signal(0);
-    } else {
-        CoreTiming::ScheduleEvent(CoreTiming::nsToCycles(initial), kernel.TimerCallbackEventType(),
-                                  callback_handle);
-    }
-}
-
-void Timer::Cancel() {
-    CoreTiming::UnscheduleEvent(kernel.TimerCallbackEventType(), callback_handle);
-}
-
-void Timer::Clear() {
-    signaled = false;
-}
-
-void Timer::Signal(int cycles_late) {
-    LOG_TRACE(Kernel, "Timer {} fired", GetObjectId());
-
-    signaled = true;
-
-    // Resume all waiting threads
-    WakeupAllWaitingThreads();
-
-    if (interval_delay != 0) {
-        // Reschedule the timer with the interval delay
-        CoreTiming::ScheduleEvent(CoreTiming::nsToCycles(interval_delay) - cycles_late,
-                                  kernel.TimerCallbackEventType(), callback_handle);
-    }
-}
-
-} // namespace Kernel

src/core/hle/kernel/timer.h

@@ -1,88 +0,0 @@
-// Copyright 2015 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
-
-#pragma once
-
-#include "common/common_types.h"
-#include "core/hle/kernel/object.h"
-#include "core/hle/kernel/wait_object.h"
-
-namespace Kernel {
-
-class KernelCore;
-
-class Timer final : public WaitObject {
-public:
-    /**
-     * Creates a timer
-     * @param kernel The kernel instance to create the timer callback handle for.
-     * @param reset_type ResetType describing how to create the timer
-     * @param name Optional name of timer
-     * @return The created Timer
-     */
-    static SharedPtr<Timer> Create(KernelCore& kernel, ResetType reset_type,
-                                   std::string name = "Unknown");
-
-    std::string GetTypeName() const override {
-        return "Timer";
-    }
-    std::string GetName() const override {
-        return name;
-    }
-
-    static const HandleType HANDLE_TYPE = HandleType::Timer;
-    HandleType GetHandleType() const override {
-        return HANDLE_TYPE;
-    }
-
-    ResetType GetResetType() const {
-        return reset_type;
-    }
-
-    u64 GetInitialDelay() const {
-        return initial_delay;
-    }
-
-    u64 GetIntervalDelay() const {
-        return interval_delay;
-    }
-
-    bool ShouldWait(Thread* thread) const override;
-    void Acquire(Thread* thread) override;
-
-    /**
-     * Starts the timer, with the specified initial delay and interval.
-     * @param initial Delay until the timer is first fired
-     * @param interval Delay until the timer is fired after the first time
-     */
-    void Set(s64 initial, s64 interval);
-
-    void Cancel();
-    void Clear();
-
-    /**
-     * Signals the timer, waking up any waiting threads and rescheduling it
-     * for the next interval.
-     * This method should not be called from outside the timer callback handler,
-     * lest multiple callback events get scheduled.
-     */
-    void Signal(int cycles_late);
-
-private:
-    explicit Timer(KernelCore& kernel);
-    ~Timer() override;
-
-    ResetType reset_type; ///< The ResetType of this timer
-
-    u64 initial_delay;  ///< The delay until the timer fires for the first time
-    u64 interval_delay; ///< The delay until the timer fires after the first time
-
-    bool signaled;    ///< Whether the timer has been signaled or not
-    std::string name; ///< Name of timer (optional)
-
-    /// Handle used as userdata to reference this object when inserting into the CoreTiming queue.
-    Handle callback_handle;
-};
-
-} // namespace Kernel

src/yuzu/debugger/wait_tree.cpp

@@ -13,7 +13,6 @@
 #include "core/hle/kernel/readable_event.h"
 #include "core/hle/kernel/scheduler.h"
 #include "core/hle/kernel/thread.h"
-#include "core/hle/kernel/timer.h"
 #include "core/hle/kernel/wait_object.h"
 #include "core/memory.h"
 
@@ -155,8 +154,6 @@ std::unique_ptr<WaitTreeWaitObject> WaitTreeWaitObject::make(const Kernel::WaitO
     switch (object.GetHandleType()) {
     case Kernel::HandleType::ReadableEvent:
         return std::make_unique<WaitTreeEvent>(static_cast<const Kernel::ReadableEvent&>(object));
-    case Kernel::HandleType::Timer:
-        return std::make_unique<WaitTreeTimer>(static_cast<const Kernel::Timer&>(object));
     case Kernel::HandleType::Thread:
         return std::make_unique<WaitTreeThread>(static_cast<const Kernel::Thread&>(object));
     default:
@@ -348,23 +345,6 @@ std::vector<std::unique_ptr<WaitTreeItem>> WaitTreeEvent::GetChildren() const {
     return list;
 }
 
-WaitTreeTimer::WaitTreeTimer(const Kernel::Timer& object) : WaitTreeWaitObject(object) {}
-WaitTreeTimer::~WaitTreeTimer() = default;
-
-std::vector<std::unique_ptr<WaitTreeItem>> WaitTreeTimer::GetChildren() const {
-    std::vector<std::unique_ptr<WaitTreeItem>> list(WaitTreeWaitObject::GetChildren());
-
-    const auto& timer = static_cast<const Kernel::Timer&>(object);
-
-    list.push_back(std::make_unique<WaitTreeText>(
-        tr("reset type = %1").arg(GetResetTypeQString(timer.GetResetType()))));
-    list.push_back(
-        std::make_unique<WaitTreeText>(tr("initial delay = %1").arg(timer.GetInitialDelay())));
-    list.push_back(
-        std::make_unique<WaitTreeText>(tr("interval delay = %1").arg(timer.GetIntervalDelay())));
-    return list;
-}
-
 WaitTreeThreadList::WaitTreeThreadList(const std::vector<Kernel::SharedPtr<Kernel::Thread>>& list)
     : thread_list(list) {}
 WaitTreeThreadList::~WaitTreeThreadList() = default;

src/yuzu/debugger/wait_tree.h

@@ -20,7 +20,6 @@ namespace Kernel {
 class ReadableEvent;
 class WaitObject;
 class Thread;
-class Timer;
 } // namespace Kernel
 
 class WaitTreeThread;
@@ -150,15 +149,6 @@ public:
     std::vector<std::unique_ptr<WaitTreeItem>> GetChildren() const override;
 };
 
-class WaitTreeTimer : public WaitTreeWaitObject {
-    Q_OBJECT
-public:
-    explicit WaitTreeTimer(const Kernel::Timer& object);
-    ~WaitTreeTimer() override;
-
-    std::vector<std::unique_ptr<WaitTreeItem>> GetChildren() const override;
-};
-
 class WaitTreeThreadList : public WaitTreeExpandableItem {
     Q_OBJECT
 public: