diff --git a/Source/Core/Core/CoreTiming.cpp b/Source/Core/Core/CoreTiming.cpp
index 74247e442c..fe06a3329d 100644
--- a/Source/Core/Core/CoreTiming.cpp
+++ b/Source/Core/Core/CoreTiming.cpp
@@ -19,6 +19,7 @@
 #include "Core/Config/MainSettings.h"
 #include "Core/Core.h"
 #include "Core/PowerPC/PowerPC.h"
+#include "Core/System.h"
 
 #include "VideoCommon/Fifo.h"
 #include "VideoCommon/VideoBackendBase.h"
@@ -82,7 +83,7 @@ static float s_config_OC_factor;
 static float s_config_OC_inv_factor;
 static bool s_config_sync_on_skip_idle;
 
-static void EmptyTimedCallback(u64 userdata, s64 cyclesLate)
+static void EmptyTimedCallback(Core::System& system, u64 userdata, s64 cyclesLate)
 {
 }
 
@@ -345,7 +346,7 @@ void Advance()
     Event evt = std::move(s_event_queue.front());
     std::pop_heap(s_event_queue.begin(), s_event_queue.end(), std::greater<Event>());
     s_event_queue.pop_back();
-    evt.type->callback(evt.userdata, g.global_timer - evt.time);
+    evt.type->callback(Core::System::GetInstance(), evt.userdata, g.global_timer - evt.time);
   }
 
   s_is_global_timer_sane = false;
diff --git a/Source/Core/Core/CoreTiming.h b/Source/Core/Core/CoreTiming.h
index 255aa612ca..64a5e81a74 100644
--- a/Source/Core/Core/CoreTiming.h
+++ b/Source/Core/Core/CoreTiming.h
@@ -21,6 +21,11 @@
 
 class PointerWrap;
 
+namespace Core
+{
+class System;
+}
+
 namespace CoreTiming
 {
 // These really shouldn't be global, but jit64 accesses them directly
@@ -39,7 +44,7 @@ extern Globals g;
 void Init();
 void Shutdown();
 
-typedef void (*TimedCallback)(u64 userdata, s64 cyclesLate);
+typedef void (*TimedCallback)(Core::System& system, u64 userdata, s64 cyclesLate);
 
 // This should only be called from the CPU thread, if you are calling it any other thread, you are
 // doing something evil
diff --git a/Source/Core/Core/HW/AudioInterface.cpp b/Source/Core/Core/HW/AudioInterface.cpp
index eddb9016b1..4a3f4cd254 100644
--- a/Source/Core/Core/HW/AudioInterface.cpp
+++ b/Source/Core/Core/HW/AudioInterface.cpp
@@ -198,12 +198,12 @@ int GetAIPeriod()
   return static_cast<int>(std::min(period, s_period));
 }
 
-void Update(u64 userdata, s64 cycles_late)
+static void Update(Core::System& system, u64 userdata, s64 cycles_late)
 {
   if (!IsPlaying())
     return;
 
-  auto& state = Core::System::GetInstance().GetAudioInterfaceState().GetData();
+  auto& state = system.GetAudioInterfaceState().GetData();
 
   const u64 diff = CoreTiming::GetTicks() - state.last_cpu_time;
   if (diff > state.cpu_cycles_per_sample)
diff --git a/Source/Core/Core/HW/DSP.cpp b/Source/Core/Core/HW/DSP.cpp
index 5ebe4a6680..f9d6cd7604 100644
--- a/Source/Core/Core/HW/DSP.cpp
+++ b/Source/Core/Core/HW/DSP.cpp
@@ -177,13 +177,13 @@ void DoState(PointerWrap& p)
 
 static void UpdateInterrupts();
 static void Do_ARAM_DMA();
-static void GenerateDSPInterrupt(u64 DSPIntType, s64 cyclesLate = 0);
+static void GenerateDSPInterrupt(Core::System& system, u64 DSPIntType, s64 cyclesLate = 0);
 
-static void CompleteARAM(u64 userdata, s64 cyclesLate)
+static void CompleteARAM(Core::System& system, u64 userdata, s64 cyclesLate)
 {
-  auto& state = Core::System::GetInstance().GetDSPState().GetData();
+  auto& state = system.GetDSPState().GetData();
   state.dsp_control.DMAState = 0;
-  GenerateDSPInterrupt(INT_ARAM);
+  GenerateDSPInterrupt(system, INT_ARAM);
 }
 
 DSPEmulator* GetDSPEmulator()
@@ -471,9 +471,9 @@ static void UpdateInterrupts()
   ProcessorInterface::SetInterrupt(ProcessorInterface::INT_CAUSE_DSP, ints_set);
 }
 
-static void GenerateDSPInterrupt(u64 DSPIntType, s64 cyclesLate)
+static void GenerateDSPInterrupt(Core::System& system, u64 DSPIntType, s64 cyclesLate)
 {
-  auto& state = Core::System::GetInstance().GetDSPState().GetData();
+  auto& state = system.GetDSPState().GetData();
 
   // The INT_* enumeration members have values that reflect their bit positions in
   // DSP_CONTROL - we mask by (INT_DSP | INT_ARAM | INT_AID) just to ensure people
@@ -512,7 +512,8 @@ void UpdateDSPSlice(int cycles)
 // This happens at 4 khz, since 32 bytes at 4khz = 4 bytes at 32 khz (16bit stereo pcm)
 void UpdateAudioDMA()
 {
-  auto& state = Core::System::GetInstance().GetDSPState().GetData();
+  auto& system = Core::System::GetInstance();
+  auto& state = system.GetDSPState().GetData();
 
   static short zero_samples[8 * 2] = {0};
   if (state.audio_dma.AudioDMAControl.Enable)
@@ -534,7 +535,7 @@ void UpdateAudioDMA()
       state.audio_dma.current_source_address = state.audio_dma.SourceAddress;
       state.audio_dma.remaining_blocks_count = state.audio_dma.AudioDMAControl.NumBlocks;
 
-      GenerateDSPInterrupt(DSP::INT_AID);
+      GenerateDSPInterrupt(system, DSP::INT_AID);
     }
   }
   else
diff --git a/Source/Core/Core/HW/DVD/DVDInterface.cpp b/Source/Core/Core/HW/DVD/DVDInterface.cpp
index d7d328ee22..ac90fd4d76 100644
--- a/Source/Core/Core/HW/DVD/DVDInterface.cpp
+++ b/Source/Core/Core/HW/DVD/DVDInterface.cpp
@@ -188,10 +188,10 @@ DVDInterfaceState::DVDInterfaceState() : m_data(std::make_unique<Data>())
 
 DVDInterfaceState::~DVDInterfaceState() = default;
 
-static void AutoChangeDiscCallback(u64 userdata, s64 cyclesLate);
-static void EjectDiscCallback(u64 userdata, s64 cyclesLate);
-static void InsertDiscCallback(u64 userdata, s64 cyclesLate);
-static void FinishExecutingCommandCallback(u64 userdata, s64 cycles_late);
+static void AutoChangeDiscCallback(Core::System& system, u64 userdata, s64 cyclesLate);
+static void EjectDiscCallback(Core::System& system, u64 userdata, s64 cyclesLate);
+static void InsertDiscCallback(Core::System& system, u64 userdata, s64 cyclesLate);
+static void FinishExecutingCommandCallback(Core::System& system, u64 userdata, s64 cycles_late);
 
 static void SetLidOpen();
 
@@ -531,19 +531,19 @@ bool IsDiscInside()
   return DVDThread::HasDisc();
 }
 
-static void AutoChangeDiscCallback(u64 userdata, s64 cyclesLate)
+static void AutoChangeDiscCallback(Core::System& system, u64 userdata, s64 cyclesLate)
 {
   AutoChangeDisc();
 }
 
-static void EjectDiscCallback(u64 userdata, s64 cyclesLate)
+static void EjectDiscCallback(Core::System& system, u64 userdata, s64 cyclesLate)
 {
   SetDisc(nullptr, {});
 }
 
-static void InsertDiscCallback(u64 userdata, s64 cyclesLate)
+static void InsertDiscCallback(Core::System& system, u64 userdata, s64 cyclesLate)
 {
-  auto& state = Core::System::GetInstance().GetDVDInterfaceState().GetData();
+  auto& state = system.GetDVDInterfaceState().GetData();
   std::unique_ptr<DiscIO::VolumeDisc> new_disc = DiscIO::CreateDisc(state.disc_path_to_insert);
 
   if (new_disc)
@@ -1370,7 +1370,7 @@ static u64 PackFinishExecutingCommandUserdata(ReplyType reply_type, DIInterruptT
   return (static_cast<u64>(reply_type) << 32) + static_cast<u32>(interrupt_type);
 }
 
-void FinishExecutingCommandCallback(u64 userdata, s64 cycles_late)
+void FinishExecutingCommandCallback(Core::System& system, u64 userdata, s64 cycles_late)
 {
   ReplyType reply_type = static_cast<ReplyType>(userdata >> 32);
   DIInterruptType interrupt_type = static_cast<DIInterruptType>(userdata & 0xFFFFFFFF);
diff --git a/Source/Core/Core/HW/DVD/DVDThread.cpp b/Source/Core/Core/HW/DVD/DVDThread.cpp
index 2cd0e35246..ea7f31f783 100644
--- a/Source/Core/Core/HW/DVD/DVDThread.cpp
+++ b/Source/Core/Core/HW/DVD/DVDThread.cpp
@@ -72,7 +72,7 @@ static void StartReadInternal(bool copy_to_ram, u32 output_address, u64 dvd_offs
                               const DiscIO::Partition& partition,
                               DVDInterface::ReplyType reply_type, s64 ticks_until_completion);
 
-static void FinishRead(u64 id, s64 cycles_late);
+static void FinishRead(Core::System& system, u64 id, s64 cycles_late);
 
 struct DVDThreadState::Data
 {
@@ -328,9 +328,9 @@ static void StartReadInternal(bool copy_to_ram, u32 output_address, u64 dvd_offs
   CoreTiming::ScheduleEvent(ticks_until_completion, state.finish_read, id);
 }
 
-static void FinishRead(u64 id, s64 cycles_late)
+static void FinishRead(Core::System& system, u64 id, s64 cycles_late)
 {
-  auto& state = Core::System::GetInstance().GetDVDThreadState().GetData();
+  auto& state = system.GetDVDThreadState().GetData();
 
   // We can't simply pop result_queue and always get the ReadResult
   // we want, because the DVD thread may add ReadResults to the queue
diff --git a/Source/Core/Core/HW/EXI/EXI.cpp b/Source/Core/Core/HW/EXI/EXI.cpp
index 461524a689..350ed22203 100644
--- a/Source/Core/Core/HW/EXI/EXI.cpp
+++ b/Source/Core/Core/HW/EXI/EXI.cpp
@@ -43,8 +43,8 @@ ExpansionInterfaceState::ExpansionInterfaceState() : m_data(std::make_unique<Dat
 
 ExpansionInterfaceState::~ExpansionInterfaceState() = default;
 
-static void ChangeDeviceCallback(u64 userdata, s64 cyclesLate);
-static void UpdateInterruptsCallback(u64 userdata, s64 cycles_late);
+static void ChangeDeviceCallback(Core::System& system, u64 userdata, s64 cyclesLate);
+static void UpdateInterruptsCallback(Core::System& system, u64 userdata, s64 cycles_late);
 
 namespace
 {
@@ -214,13 +214,13 @@ void RegisterMMIO(MMIO::Mapping* mmio, u32 base)
   }
 }
 
-static void ChangeDeviceCallback(u64 userdata, s64 cyclesLate)
+static void ChangeDeviceCallback(Core::System& system, u64 userdata, s64 cyclesLate)
 {
   u8 channel = (u8)(userdata >> 32);
   u8 type = (u8)(userdata >> 16);
   u8 num = (u8)userdata;
 
-  auto& state = Core::System::GetInstance().GetExpansionInterfaceState().GetData();
+  auto& state = system.GetExpansionInterfaceState().GetData();
   state.channels.at(channel)->AddDevice(static_cast<EXIDeviceType>(type), num);
 }
 
@@ -270,7 +270,7 @@ void UpdateInterrupts()
   ProcessorInterface::SetInterrupt(ProcessorInterface::INT_CAUSE_EXI, causeInt);
 }
 
-static void UpdateInterruptsCallback(u64 userdata, s64 cycles_late)
+static void UpdateInterruptsCallback(Core::System& system, u64 userdata, s64 cycles_late)
 {
   UpdateInterrupts();
 }
diff --git a/Source/Core/Core/HW/EXI/EXI_DeviceMemoryCard.cpp b/Source/Core/Core/HW/EXI/EXI_DeviceMemoryCard.cpp
index c054c47404..2e97cc67e6 100644
--- a/Source/Core/Core/HW/EXI/EXI_DeviceMemoryCard.cpp
+++ b/Source/Core/Core/HW/EXI/EXI_DeviceMemoryCard.cpp
@@ -71,12 +71,12 @@ void CEXIMemoryCard::EventCompleteFindInstance(u64 userdata,
   }
 }
 
-void CEXIMemoryCard::CmdDoneCallback(u64 userdata, s64)
+void CEXIMemoryCard::CmdDoneCallback(Core::System& system, u64 userdata, s64)
 {
   EventCompleteFindInstance(userdata, [](CEXIMemoryCard* instance) { instance->CmdDone(); });
 }
 
-void CEXIMemoryCard::TransferCompleteCallback(u64 userdata, s64)
+void CEXIMemoryCard::TransferCompleteCallback(Core::System& system, u64 userdata, s64)
 {
   EventCompleteFindInstance(userdata,
                             [](CEXIMemoryCard* instance) { instance->TransferComplete(); });
diff --git a/Source/Core/Core/HW/EXI/EXI_DeviceMemoryCard.h b/Source/Core/Core/HW/EXI/EXI_DeviceMemoryCard.h
index c472448d09..402518892d 100644
--- a/Source/Core/Core/HW/EXI/EXI_DeviceMemoryCard.h
+++ b/Source/Core/Core/HW/EXI/EXI_DeviceMemoryCard.h
@@ -14,6 +14,10 @@
 class MemoryCardBase;
 class PointerWrap;
 
+namespace Core
+{
+class System;
+}
 namespace Memcard
 {
 struct HeaderData;
@@ -58,10 +62,10 @@ private:
                                         std::function<void(CEXIMemoryCard*)> callback);
 
   // Scheduled when a command that required delayed end signaling is done.
-  static void CmdDoneCallback(u64 userdata, s64 cyclesLate);
+  static void CmdDoneCallback(Core::System& system, u64 userdata, s64 cyclesLate);
 
   // Scheduled when memory card is done transferring data
-  static void TransferCompleteCallback(u64 userdata, s64 cyclesLate);
+  static void TransferCompleteCallback(Core::System& system, u64 userdata, s64 cyclesLate);
 
   // Signals that the command that was previously executed is now done.
   void CmdDone();
diff --git a/Source/Core/Core/HW/ProcessorInterface.cpp b/Source/Core/Core/HW/ProcessorInterface.cpp
index 37c10580bd..698069a261 100644
--- a/Source/Core/Core/HW/ProcessorInterface.cpp
+++ b/Source/Core/Core/HW/ProcessorInterface.cpp
@@ -39,13 +39,13 @@ static u32 m_ResetCode;
 
 // ID and callback for scheduling reset button presses/releases
 static CoreTiming::EventType* toggleResetButton;
-static void ToggleResetButtonCallback(u64 userdata, s64 cyclesLate);
+static void ToggleResetButtonCallback(Core::System& system, u64 userdata, s64 cyclesLate);
 
 static CoreTiming::EventType* iosNotifyResetButton;
-static void IOSNotifyResetButtonCallback(u64 userdata, s64 cyclesLate);
+static void IOSNotifyResetButtonCallback(Core::System& system, u64 userdata, s64 cyclesLate);
 
 static CoreTiming::EventType* iosNotifyPowerButton;
-static void IOSNotifyPowerButtonCallback(u64 userdata, s64 cyclesLate);
+static void IOSNotifyPowerButtonCallback(Core::System& system, u64 userdata, s64 cyclesLate);
 
 // Let the PPC know that an external exception is set/cleared
 void UpdateException();
@@ -230,12 +230,12 @@ static void SetResetButton(bool set)
   SetInterrupt(INT_CAUSE_RST_BUTTON, !set);
 }
 
-static void ToggleResetButtonCallback(u64 userdata, s64 cyclesLate)
+static void ToggleResetButtonCallback(Core::System& system, u64 userdata, s64 cyclesLate)
 {
   SetResetButton(!!userdata);
 }
 
-static void IOSNotifyResetButtonCallback(u64 userdata, s64 cyclesLate)
+static void IOSNotifyResetButtonCallback(Core::System& system, u64 userdata, s64 cyclesLate)
 {
   const auto ios = IOS::HLE::GetIOS();
   if (!ios)
@@ -246,7 +246,7 @@ static void IOSNotifyResetButtonCallback(u64 userdata, s64 cyclesLate)
     std::static_pointer_cast<IOS::HLE::STMEventHookDevice>(stm)->ResetButton();
 }
 
-static void IOSNotifyPowerButtonCallback(u64 userdata, s64 cyclesLate)
+static void IOSNotifyPowerButtonCallback(Core::System& system, u64 userdata, s64 cyclesLate)
 {
   const auto ios = IOS::HLE::GetIOS();
   if (!ios)
diff --git a/Source/Core/Core/HW/SI/SI.cpp b/Source/Core/Core/HW/SI/SI.cpp
index 1a199e1fa6..ef0be4f19c 100644
--- a/Source/Core/Core/HW/SI/SI.cpp
+++ b/Source/Core/Core/HW/SI/SI.cpp
@@ -243,10 +243,10 @@ static void SetNoResponse(u32 channel)
   }
 }
 
-static void ChangeDeviceCallback(u64 user_data, s64 cycles_late)
+static void ChangeDeviceCallback(Core::System& system, u64 user_data, s64 cycles_late)
 {
   // The purpose of this callback is to simply re-enable device changes.
-  auto& state = Core::System::GetInstance().GetSerialInterfaceState().GetData();
+  auto& state = system.GetSerialInterfaceState().GetData();
   state.channel[user_data].has_recent_device_change = false;
 }
 
@@ -295,9 +295,9 @@ constexpr s32 ConvertSILengthField(u32 field)
   return ((field - 1) & SI_XFER_LENGTH_MASK) + 1;
 }
 
-static void RunSIBuffer(u64 user_data, s64 cycles_late)
+static void RunSIBuffer(Core::System& system, u64 user_data, s64 cycles_late)
 {
-  auto& state = Core::System::GetInstance().GetSerialInterfaceState().GetData();
+  auto& state = system.GetSerialInterfaceState().GetData();
   if (state.com_csr.TSTART)
   {
     const s32 request_length = ConvertSILengthField(state.com_csr.OUTLNGTH);
@@ -380,9 +380,9 @@ void DoState(PointerWrap& p)
 }
 
 template <int device_number>
-static void DeviceEventCallback(u64 userdata, s64 cyclesLate)
+static void DeviceEventCallback(Core::System& system, u64 userdata, s64 cyclesLate)
 {
-  auto& state = Core::System::GetInstance().GetSerialInterfaceState().GetData();
+  auto& state = system.GetSerialInterfaceState().GetData();
   state.channel[device_number].device->OnEvent(userdata, cyclesLate);
 }
 
@@ -555,7 +555,8 @@ void RegisterMMIO(MMIO::Mapping* mmio, u32 base)
 
   mmio->Register(base | SI_COM_CSR, MMIO::DirectRead<u32>(&state.com_csr.hex),
                  MMIO::ComplexWrite<u32>([](u32, u32 val) {
-                   auto& state = Core::System::GetInstance().GetSerialInterfaceState().GetData();
+                   auto& system = Core::System::GetInstance();
+                   auto& state = system.GetSerialInterfaceState().GetData();
                    const USIComCSR tmp_com_csr(val);
 
                    state.com_csr.CHANNEL = tmp_com_csr.CHANNEL.Value();
@@ -575,7 +576,7 @@ void RegisterMMIO(MMIO::Mapping* mmio, u32 base)
                      if (state.com_csr.TSTART)
                        CoreTiming::RemoveEvent(state.event_type_tranfer_pending);
                      state.com_csr.TSTART = 1;
-                     RunSIBuffer(0, 0);
+                     RunSIBuffer(system, 0, 0);
                    }
 
                    if (!state.com_csr.TSTART)
diff --git a/Source/Core/Core/HW/SystemTimers.cpp b/Source/Core/Core/HW/SystemTimers.cpp
index 6a41362b82..eab06b28d7 100644
--- a/Source/Core/Core/HW/SystemTimers.cpp
+++ b/Source/Core/Core/HW/SystemTimers.cpp
@@ -100,7 +100,7 @@ std::mutex s_emu_to_real_time_mutex;
 u64 s_time_spent_sleeping;
 
 // DSP/CPU timeslicing.
-void DSPCallback(u64 userdata, s64 cyclesLate)
+void DSPCallback(Core::System& system, u64 userdata, s64 cyclesLate)
 {
   // splits up the cycle budget in case lle is used
   // for hle, just gives all of the slice to hle
@@ -115,13 +115,13 @@ int GetAudioDMACallbackPeriod()
          (Mixer::FIXED_SAMPLE_RATE_DIVIDEND * 4 / 32);
 }
 
-void AudioDMACallback(u64 userdata, s64 cyclesLate)
+void AudioDMACallback(Core::System& system, u64 userdata, s64 cyclesLate)
 {
   DSP::UpdateAudioDMA();  // Push audio to speakers.
   CoreTiming::ScheduleEvent(GetAudioDMACallbackPeriod() - cyclesLate, et_AudioDMA);
 }
 
-void IPC_HLE_UpdateCallback(u64 userdata, s64 cyclesLate)
+void IPC_HLE_UpdateCallback(Core::System& system, u64 userdata, s64 cyclesLate)
 {
   if (SConfig::GetInstance().bWii)
   {
@@ -130,19 +130,19 @@ void IPC_HLE_UpdateCallback(u64 userdata, s64 cyclesLate)
   }
 }
 
-void VICallback(u64 userdata, s64 cyclesLate)
+void VICallback(Core::System& system, u64 userdata, s64 cyclesLate)
 {
   VideoInterface::Update(CoreTiming::GetTicks() - cyclesLate);
   CoreTiming::ScheduleEvent(VideoInterface::GetTicksPerHalfLine() - cyclesLate, et_VI);
 }
 
-void DecrementerCallback(u64 userdata, s64 cyclesLate)
+void DecrementerCallback(Core::System& system, u64 userdata, s64 cyclesLate)
 {
   PowerPC::ppcState.spr[SPR_DEC] = 0xFFFFFFFF;
   PowerPC::ppcState.Exceptions |= EXCEPTION_DECREMENTER;
 }
 
-void PatchEngineCallback(u64 userdata, s64 cycles_late)
+void PatchEngineCallback(Core::System& system, u64 userdata, s64 cycles_late)
 {
   // We have 2 periods, a 1000 cycle error period and the VI period.
   // We have to carefully combine these together so that we stay on the VI period without drifting.
@@ -167,7 +167,7 @@ void PatchEngineCallback(u64 userdata, s64 cycles_late)
   CoreTiming::ScheduleEvent(next_schedule, et_PatchEngine, cycles_pruned);
 }
 
-void ThrottleCallback(u64 deadline, s64 cyclesLate)
+void ThrottleCallback(Core::System& system, u64 deadline, s64 cyclesLate)
 {
   // Allow the GPU thread to sleep. Setting this flag here limits the wakeups to 1 kHz.
   Fifo::GpuMaySleep();
diff --git a/Source/Core/Core/HW/WII_IPC.cpp b/Source/Core/Core/HW/WII_IPC.cpp
index 46bb74a5d4..aac45c68a1 100644
--- a/Source/Core/Core/HW/WII_IPC.cpp
+++ b/Source/Core/Core/HW/WII_IPC.cpp
@@ -112,7 +112,7 @@ Common::Flags<GPIO> g_gpio_out;
 static u32 resets;
 
 static CoreTiming::EventType* updateInterrupts;
-static void UpdateInterrupts(u64 = 0, s64 cyclesLate = 0);
+static void UpdateInterrupts(Core::System& system, u64 userdata, s64 cyclesLate);
 
 void DoState(PointerWrap& p)
 {
@@ -283,7 +283,7 @@ void RegisterMMIO(MMIO::Mapping* mmio, u32 base)
   mmio->Register(base | UNK_1D0, MMIO::Constant<u32>(0), MMIO::Nop<u32>());
 }
 
-static void UpdateInterrupts(u64 userdata, s64 cyclesLate)
+static void UpdateInterrupts(Core::System& system, u64 userdata, s64 cyclesLate)
 {
   if ((ctrl.Y1 & ctrl.IY1) || (ctrl.Y2 & ctrl.IY2))
   {
diff --git a/Source/Core/Core/IOS/DI/DI.cpp b/Source/Core/Core/IOS/DI/DI.cpp
index 5632cc4bee..c15a015ee8 100644
--- a/Source/Core/Core/IOS/DI/DI.cpp
+++ b/Source/Core/Core/IOS/DI/DI.cpp
@@ -624,7 +624,7 @@ void DIDevice::InterruptFromDVDInterface(DVDInterface::DIInterruptType interrupt
   }
 }
 
-void DIDevice::FinishDICommandCallback(u64 userdata, s64 ticksbehind)
+void DIDevice::FinishDICommandCallback(Core::System& system, u64 userdata, s64 ticksbehind)
 {
   const DIResult result = static_cast<DIResult>(userdata);
 
diff --git a/Source/Core/Core/IOS/DI/DI.h b/Source/Core/Core/IOS/DI/DI.h
index 43645be356..f2d5307f68 100644
--- a/Source/Core/Core/IOS/DI/DI.h
+++ b/Source/Core/Core/IOS/DI/DI.h
@@ -19,6 +19,10 @@ namespace DVDInterface
 {
 enum class DIInterruptType : int;
 }
+namespace Core
+{
+class System;
+}
 namespace CoreTiming
 {
 struct EventType;
@@ -128,7 +132,7 @@ private:
   void ChangePartition(const DiscIO::Partition partition);
   void InitializeIfFirstTime();
   void ResetDIRegisters();
-  static void FinishDICommandCallback(u64 userdata, s64 ticksbehind);
+  static void FinishDICommandCallback(Core::System& system, u64 userdata, s64 ticksbehind);
   void FinishDICommand(DIResult result);
 
   static CoreTiming::EventType* s_finish_executing_di_command;
diff --git a/Source/Core/Core/IOS/ES/ES.cpp b/Source/Core/Core/IOS/ES/ES.cpp
index b8c2a4a115..2424a8c87d 100644
--- a/Source/Core/Core/IOS/ES/ES.cpp
+++ b/Source/Core/Core/IOS/ES/ES.cpp
@@ -115,13 +115,15 @@ ESDevice::ESDevice(Kernel& ios, const std::string& device_name) : Device(ios, de
 void ESDevice::InitializeEmulationState()
 {
   s_finish_init_event = CoreTiming::RegisterEvent(
-      "IOS-ESFinishInit", [](u64, s64) { GetIOS()->GetES()->FinishInit(); });
-  s_reload_ios_for_ppc_launch_event =
-      CoreTiming::RegisterEvent("IOS-ESReloadIOSForPPCLaunch", [](u64 ios_id, s64) {
+      "IOS-ESFinishInit", [](Core::System& system, u64, s64) { GetIOS()->GetES()->FinishInit(); });
+  s_reload_ios_for_ppc_launch_event = CoreTiming::RegisterEvent(
+      "IOS-ESReloadIOSForPPCLaunch", [](Core::System& system, u64 ios_id, s64) {
         GetIOS()->GetES()->LaunchTitle(ios_id, HangPPC::Yes);
       });
-  s_bootstrap_ppc_for_launch_event = CoreTiming::RegisterEvent(
-      "IOS-ESBootstrapPPCForLaunch", [](u64, s64) { GetIOS()->GetES()->BootstrapPPC(); });
+  s_bootstrap_ppc_for_launch_event =
+      CoreTiming::RegisterEvent("IOS-ESBootstrapPPCForLaunch", [](Core::System& system, u64, s64) {
+        GetIOS()->GetES()->BootstrapPPC();
+      });
 }
 
 void ESDevice::FinalizeEmulationState()
diff --git a/Source/Core/Core/IOS/IOS.cpp b/Source/Core/Core/IOS/IOS.cpp
index 25808585f0..9d57228394 100644
--- a/Source/Core/Core/IOS/IOS.cpp
+++ b/Source/Core/Core/IOS/IOS.cpp
@@ -876,7 +876,7 @@ IOSC& Kernel::GetIOSC()
   return m_iosc;
 }
 
-static void FinishPPCBootstrap(u64 userdata, s64 cycles_late)
+static void FinishPPCBootstrap(Core::System& system, u64 userdata, s64 cycles_late)
 {
   // See Kernel::BootstrapPPC
   const bool is_ancast = userdata == 1;
@@ -891,18 +891,20 @@ static void FinishPPCBootstrap(u64 userdata, s64 cycles_late)
 
 void Init()
 {
-  s_event_enqueue = CoreTiming::RegisterEvent("IPCEvent", [](u64 userdata, s64) {
-    if (s_ios)
-      s_ios->HandleIPCEvent(userdata);
-  });
+  s_event_enqueue =
+      CoreTiming::RegisterEvent("IPCEvent", [](Core::System& system, u64 userdata, s64) {
+        if (s_ios)
+          s_ios->HandleIPCEvent(userdata);
+      });
 
   ESDevice::InitializeEmulationState();
 
   s_event_finish_ppc_bootstrap =
       CoreTiming::RegisterEvent("IOSFinishPPCBootstrap", FinishPPCBootstrap);
 
-  s_event_finish_ios_boot = CoreTiming::RegisterEvent(
-      "IOSFinishIOSBoot", [](u64 ios_title_id, s64) { FinishIOSBoot(ios_title_id); });
+  s_event_finish_ios_boot =
+      CoreTiming::RegisterEvent("IOSFinishIOSBoot", [](Core::System& system, u64 ios_title_id,
+                                                       s64) { FinishIOSBoot(ios_title_id); });
 
   DIDevice::s_finish_executing_di_command =
       CoreTiming::RegisterEvent("FinishDICommand", DIDevice::FinishDICommandCallback);
diff --git a/Source/Core/Core/PowerPC/GDBStub.cpp b/Source/Core/Core/PowerPC/GDBStub.cpp
index 2fe39b75fd..775f189bb0 100644
--- a/Source/Core/Core/PowerPC/GDBStub.cpp
+++ b/Source/Core/Core/PowerPC/GDBStub.cpp
@@ -124,7 +124,7 @@ static void Hex2mem(u8* dst, u8* src, u32 len)
   }
 }
 
-static void UpdateCallback(u64 userdata, s64 cycles_late)
+static void UpdateCallback(Core::System& system, u64 userdata, s64 cycles_late)
 {
   ProcessCommands(false);
   if (IsActive())
diff --git a/Source/Core/Core/PowerPC/PowerPC.cpp b/Source/Core/Core/PowerPC/PowerPC.cpp
index d25deca939..10de0f9c77 100644
--- a/Source/Core/Core/PowerPC/PowerPC.cpp
+++ b/Source/Core/Core/PowerPC/PowerPC.cpp
@@ -68,7 +68,7 @@ void PairedSingle::SetPS1(double value)
   ps1 = Common::BitCast<u64>(value);
 }
 
-static void InvalidateCacheThreadSafe(u64 userdata, s64 cyclesLate)
+static void InvalidateCacheThreadSafe(Core::System& system, u64 userdata, s64 cyclesLate)
 {
   ppcState.iCache.Invalidate(static_cast<u32>(userdata));
 }
diff --git a/Source/Core/VideoCommon/CommandProcessor.cpp b/Source/Core/VideoCommon/CommandProcessor.cpp
index 0ab1eb7aee..a5e5591276 100644
--- a/Source/Core/VideoCommon/CommandProcessor.cpp
+++ b/Source/Core/VideoCommon/CommandProcessor.cpp
@@ -49,7 +49,7 @@ static bool IsOnThread()
   return Core::System::GetInstance().IsDualCoreMode();
 }
 
-static void UpdateInterrupts_Wrapper(u64 userdata, s64 cyclesLate)
+static void UpdateInterrupts_Wrapper(Core::System& system, u64 userdata, s64 cyclesLate)
 {
   UpdateInterrupts(userdata);
 }
diff --git a/Source/Core/VideoCommon/Fifo.cpp b/Source/Core/VideoCommon/Fifo.cpp
index faea454147..a69a83b00f 100644
--- a/Source/Core/VideoCommon/Fifo.cpp
+++ b/Source/Core/VideoCommon/Fifo.cpp
@@ -595,12 +595,12 @@ static int WaitForGpuThread(int ticks)
   return GPU_TIME_SLOT_SIZE;
 }
 
-static void SyncGPUCallback(u64 ticks, s64 cyclesLate)
+static void SyncGPUCallback(Core::System& system, u64 ticks, s64 cyclesLate)
 {
   ticks += cyclesLate;
   int next = -1;
 
-  if (!Core::System::GetInstance().IsDualCoreMode() || s_use_deterministic_gpu_thread)
+  if (!system.IsDualCoreMode() || s_use_deterministic_gpu_thread)
   {
     next = RunGpuOnCpu((int)ticks);
   }
diff --git a/Source/Core/VideoCommon/PixelEngine.cpp b/Source/Core/VideoCommon/PixelEngine.cpp
index d2cd5ef332..c110ffa284 100644
--- a/Source/Core/VideoCommon/PixelEngine.cpp
+++ b/Source/Core/VideoCommon/PixelEngine.cpp
@@ -182,7 +182,7 @@ void DoState(PointerWrap& p)
 }
 
 static void UpdateInterrupts();
-static void SetTokenFinish_OnMainThread(u64 userdata, s64 cyclesLate);
+static void SetTokenFinish_OnMainThread(Core::System& system, u64 userdata, s64 cyclesLate);
 
 void Init()
 {
@@ -297,7 +297,7 @@ static void UpdateInterrupts()
                                    s_signal_finish_interrupt && m_Control.pe_finish_enable);
 }
 
-static void SetTokenFinish_OnMainThread(u64 userdata, s64 cyclesLate)
+static void SetTokenFinish_OnMainThread(Core::System& system, u64 userdata, s64 cyclesLate)
 {
   std::unique_lock<std::mutex> lk(s_token_finish_mutex);
   s_event_raised = false;
diff --git a/Source/UnitTests/Core/CoreTimingTest.cpp b/Source/UnitTests/Core/CoreTimingTest.cpp
index b08919679d..b8ca8cc01b 100644
--- a/Source/UnitTests/Core/CoreTimingTest.cpp
+++ b/Source/UnitTests/Core/CoreTimingTest.cpp
@@ -25,7 +25,7 @@ static u64 s_expected_callback = 0;
 static s64 s_lateness = 0;
 
 template <unsigned int IDX>
-void CallbackTemplate(u64 userdata, s64 lateness)
+void CallbackTemplate(Core::System& system, u64 userdata, s64 lateness)
 {
   static_assert(IDX < CB_IDS.size(), "IDX out of range");
   s_callbacks_ran_flags.set(IDX);
@@ -121,7 +121,7 @@ namespace SharedSlotTest
 static unsigned int s_counter = 0;
 
 template <unsigned int ID>
-void FifoCallback(u64 userdata, s64 lateness)
+void FifoCallback(Core::System& system, u64 userdata, s64 lateness)
 {
   static_assert(ID < CB_IDS.size(), "ID out of range");
   s_callbacks_ran_flags.set(ID);
@@ -186,7 +186,7 @@ namespace ChainSchedulingTest
 {
 static int s_reschedules = 0;
 
-static void RescheduleCallback(u64 userdata, s64 lateness)
+static void RescheduleCallback(Core::System& system, u64 userdata, s64 lateness)
 {
   --s_reschedules;
   EXPECT_TRUE(s_reschedules >= 0);
@@ -241,7 +241,7 @@ namespace ScheduleIntoPastTest
 {
 static CoreTiming::EventType* s_cb_next = nullptr;
 
-static void ChainCallback(u64 userdata, s64 lateness)
+static void ChainCallback(Core::System& system, u64 userdata, s64 lateness)
 {
   EXPECT_EQ(CB_IDS[0] + 1, userdata);
   EXPECT_EQ(0, lateness);