core_timing: Convert core timing into a class

Gets rid of the largest set of mutable global state within the core.
This also paves a way for eliminating usages of GetInstance() on the
System class as a follow-up.

Note that no behavioral changes have been made, and this simply extracts
the functionality into a class. This also has the benefit of making
dependencies on the core timing functionality explicit within the
relevant interfaces.

src/core/hle/kernel/kernel.cpp

@@ -86,11 +86,11 @@ static void ThreadWakeupCallback(u64 thread_handle, [[maybe_unused]] int cycles_
 }
 
 struct KernelCore::Impl {
-    void Initialize(KernelCore& kernel) {
+    void Initialize(KernelCore& kernel, Core::Timing::CoreTiming& core_timing) {
         Shutdown();
 
         InitializeSystemResourceLimit(kernel);
-        InitializeThreads();
+        InitializeThreads(core_timing);
     }
 
     void Shutdown() {
@@ -122,9 +122,9 @@ struct KernelCore::Impl {
         ASSERT(system_resource_limit->SetLimitValue(ResourceType::Sessions, 900).IsSuccess());
     }
 
-    void InitializeThreads() {
+    void InitializeThreads(Core::Timing::CoreTiming& core_timing) {
         thread_wakeup_event_type =
-            Core::Timing::RegisterEvent("ThreadWakeupCallback", ThreadWakeupCallback);
+            core_timing.RegisterEvent("ThreadWakeupCallback", ThreadWakeupCallback);
     }
 
     std::atomic<u32> next_object_id{0};
@@ -152,8 +152,8 @@ KernelCore::~KernelCore() {
     Shutdown();
 }
 
-void KernelCore::Initialize() {
-    impl->Initialize(*this);
+void KernelCore::Initialize(Core::Timing::CoreTiming& core_timing) {
+    impl->Initialize(*this, core_timing);
 }
 
 void KernelCore::Shutdown() {

src/core/hle/kernel/kernel.h

@@ -12,8 +12,9 @@ template <typename T>
 class ResultVal;
 
 namespace Core::Timing {
+class CoreTiming;
 struct EventType;
-}
+} // namespace Core::Timing
 
 namespace Kernel {
 
@@ -39,7 +40,11 @@ public:
     KernelCore& operator=(KernelCore&&) = delete;
 
     /// Resets the kernel to a clean slate for use.
-    void Initialize();
+    ///
+    /// @param core_timing CoreTiming instance used to create any necessary
+    ///                    kernel-specific callback events.
+    ///
+    void Initialize(Core::Timing::CoreTiming& core_timing);
 
     /// Clears all resources in use by the kernel instance.
     void Shutdown();

src/core/hle/kernel/scheduler.cpp

@@ -111,7 +111,7 @@ void Scheduler::SwitchContext(Thread* new_thread) {
 
 void Scheduler::UpdateLastContextSwitchTime(Thread* thread, Process* process) {
     const u64 prev_switch_ticks = last_context_switch_time;
-    const u64 most_recent_switch_ticks = Core::Timing::GetTicks();
+    const u64 most_recent_switch_ticks = Core::System::GetInstance().CoreTiming().GetTicks();
     const u64 update_ticks = most_recent_switch_ticks - prev_switch_ticks;
 
     if (thread != nullptr) {

src/core/hle/kernel/svc.cpp

@@ -918,6 +918,7 @@ static ResultCode GetInfo(u64* result, u64 info_id, u64 handle, u64 info_sub_id)
         }
 
         const auto& system = Core::System::GetInstance();
+        const auto& core_timing = system.CoreTiming();
         const auto& scheduler = system.CurrentScheduler();
         const auto* const current_thread = scheduler.GetCurrentThread();
         const bool same_thread = current_thread == thread;
@@ -927,9 +928,9 @@ static ResultCode GetInfo(u64* result, u64 info_id, u64 handle, u64 info_sub_id)
         if (same_thread && info_sub_id == 0xFFFFFFFFFFFFFFFF) {
             const u64 thread_ticks = current_thread->GetTotalCPUTimeTicks();
 
-            out_ticks = thread_ticks + (Core::Timing::GetTicks() - prev_ctx_ticks);
+            out_ticks = thread_ticks + (core_timing.GetTicks() - prev_ctx_ticks);
         } else if (same_thread && info_sub_id == system.CurrentCoreIndex()) {
-            out_ticks = Core::Timing::GetTicks() - prev_ctx_ticks;
+            out_ticks = core_timing.GetTicks() - prev_ctx_ticks;
         }
 
         *result = out_ticks;
@@ -1546,10 +1547,11 @@ static ResultCode SignalToAddress(VAddr address, u32 type, s32 value, s32 num_to
 static u64 GetSystemTick() {
     LOG_TRACE(Kernel_SVC, "called");
 
-    const u64 result{Core::Timing::GetTicks()};
+    auto& core_timing = Core::System::GetInstance().CoreTiming();
+    const u64 result{core_timing.GetTicks()};
 
     // Advance time to defeat dumb games that busy-wait for the frame to end.
-    Core::Timing::AddTicks(400);
+    core_timing.AddTicks(400);
 
     return result;
 }

src/core/hle/kernel/thread.cpp

@@ -43,7 +43,8 @@ Thread::~Thread() = default;
 
 void Thread::Stop() {
     // Cancel any outstanding wakeup events for this thread
-    Core::Timing::UnscheduleEvent(kernel.ThreadWakeupCallbackEventType(), callback_handle);
+    Core::System::GetInstance().CoreTiming().UnscheduleEvent(kernel.ThreadWakeupCallbackEventType(),
+                                                             callback_handle);
     kernel.ThreadWakeupCallbackHandleTable().Close(callback_handle);
     callback_handle = 0;
 
@@ -85,13 +86,14 @@ void Thread::WakeAfterDelay(s64 nanoseconds) {
 
     // This function might be called from any thread so we have to be cautious and use the
     // thread-safe version of ScheduleEvent.
-    Core::Timing::ScheduleEventThreadsafe(Core::Timing::nsToCycles(nanoseconds),
-                                          kernel.ThreadWakeupCallbackEventType(), callback_handle);
+    Core::System::GetInstance().CoreTiming().ScheduleEventThreadsafe(
+        Core::Timing::nsToCycles(nanoseconds), kernel.ThreadWakeupCallbackEventType(),
+        callback_handle);
 }
 
 void Thread::CancelWakeupTimer() {
-    Core::Timing::UnscheduleEventThreadsafe(kernel.ThreadWakeupCallbackEventType(),
-                                            callback_handle);
+    Core::System::GetInstance().CoreTiming().UnscheduleEventThreadsafe(
+        kernel.ThreadWakeupCallbackEventType(), callback_handle);
 }
 
 static std::optional<s32> GetNextProcessorId(u64 mask) {
@@ -190,6 +192,7 @@ ResultVal<SharedPtr<Thread>> Thread::Create(KernelCore& kernel, std::string name
         return ResultCode(-1);
     }
 
+    auto& system = Core::System::GetInstance();
     SharedPtr<Thread> thread(new Thread(kernel));
 
     thread->thread_id = kernel.CreateNewThreadID();
@@ -198,7 +201,7 @@ ResultVal<SharedPtr<Thread>> Thread::Create(KernelCore& kernel, std::string name
     thread->stack_top = stack_top;
     thread->tpidr_el0 = 0;
     thread->nominal_priority = thread->current_priority = priority;
-    thread->last_running_ticks = Core::Timing::GetTicks();
+    thread->last_running_ticks = system.CoreTiming().GetTicks();
     thread->processor_id = processor_id;
     thread->ideal_core = processor_id;
     thread->affinity_mask = 1ULL << processor_id;
@@ -209,7 +212,7 @@ ResultVal<SharedPtr<Thread>> Thread::Create(KernelCore& kernel, std::string name
     thread->name = std::move(name);
     thread->callback_handle = kernel.ThreadWakeupCallbackHandleTable().Create(thread).Unwrap();
     thread->owner_process = &owner_process;
-    thread->scheduler = &Core::System::GetInstance().Scheduler(processor_id);
+    thread->scheduler = &system.Scheduler(processor_id);
     thread->scheduler->AddThread(thread, priority);
     thread->tls_address = thread->owner_process->MarkNextAvailableTLSSlotAsUsed(*thread);
 
@@ -258,7 +261,7 @@ void Thread::SetStatus(ThreadStatus new_status) {
     }
 
     if (status == ThreadStatus::Running) {
-        last_running_ticks = Core::Timing::GetTicks();
+        last_running_ticks = Core::System::GetInstance().CoreTiming().GetTicks();
     }
 
     status = new_status;