Merge pull request #2396 from Sonicadvance1/fix_racing_cpu_core

Fix a race condition when pausing the CPU core.

Source/Core/Core/PowerPC/Interpreter/Interpreter.cpp

@@ -277,6 +277,9 @@ void Interpreter::Run()
 			PC = NPC;
 		}
 	}
+
+	// Let the waiting thread know we are done leaving
+	PowerPC::FinishStateMove();
 }
 
 void Interpreter::unknown_instruction(UGeckoInstruction _inst)

Source/Core/Core/PowerPC/Jit64/JitAsm.cpp

@@ -216,6 +216,12 @@ void Jit64AsmRoutineManager::Generate()
 		ADD(64, R(RSP), Imm8(0x18));
 		POP(RSP);
 	}
+
+	// Let the waiting thread know we are done leaving
+	ABI_PushRegistersAndAdjustStack({}, 0);
+	ABI_CallFunction(reinterpret_cast<void *>(&PowerPC::FinishStateMove));
+	ABI_PopRegistersAndAdjustStack({}, 0);
+
 	ABI_PopRegistersAndAdjustStack(ABI_ALL_CALLEE_SAVED, 8, 16);
 	RET();
 

Source/Core/Core/PowerPC/JitArm32/JitAsm.cpp

@@ -136,6 +136,10 @@ void JitArmAsmRoutineManager::Generate()
 	if (SConfig::GetInstance().m_LocalCoreStartupParameter.bEnableDebugging)
 		SetJumpTarget(dbg_exit);
 
+	// Let the waiting thread know we are done leaving
+	MOVI2R(R0, (u32)&PowerPC::FinishStateMove);
+	BL(R0);
+
 	ADD(_SP, _SP, 4);
 
 	POP(9, R4, R5, R6, R7, R8, R9, R10, R11, _PC);  // Returns

Source/Core/Core/PowerPC/JitArm64/JitAsm.cpp

@@ -87,6 +87,10 @@ void JitArm64AsmRoutineManager::Generate()
 
 	SetJumpTarget(Exit);
 
+	// Let the waiting thread know we are done leaving
+	MOVI2R(X0, (u64)&PowerPC::FinishStateMove);
+	BLR(X0);
+
 	ABI_PopRegisters(regs_to_save);
 	RET(X30);
 

Source/Core/Core/PowerPC/PowerPC.cpp

@@ -4,6 +4,7 @@
 
 #include "Common/ChunkFile.h"
 #include "Common/CommonTypes.h"
+#include "Common/Event.h"
 #include "Common/FPURoundMode.h"
 #include "Common/MathUtil.h"
 
@@ -33,6 +34,7 @@ static volatile CPUState state = CPU_POWERDOWN;
 
 Interpreter * const interpreter = Interpreter::getInstance();
 static CoreMode mode;
+static Common::Event s_state_change;
 
 Watches watches;
 BreakPoints breakpoints;
@@ -238,16 +240,31 @@ void Start()
 
 void Pause()
 {
+	volatile CPUState old_state = state;
 	state = CPU_STEPPING;
+
+	// Wait for the CPU core to leave
+	if (old_state == CPU_RUNNING)
+		s_state_change.WaitFor(std::chrono::seconds(1));
 	Host_UpdateDisasmDialog();
 }
 
 void Stop()
 {
+	volatile CPUState old_state = state;
 	state = CPU_POWERDOWN;
+
+	// Wait for the CPU core to leave
+	if (old_state == CPU_RUNNING)
+		s_state_change.WaitFor(std::chrono::seconds(1));
 	Host_UpdateDisasmDialog();
 }
 
+void FinishStateMove()
+{
+	s_state_change.Set();
+}
+
 void UpdatePerformanceMonitor(u32 cycles, u32 num_load_stores, u32 num_fp_inst)
 {
 	switch (MMCR0.PMC1SELECT)

Source/Core/Core/PowerPC/PowerPC.h

@@ -156,6 +156,7 @@ void RunLoop();
 void Start();
 void Pause();
 void Stop();
+void FinishStateMove();
 CPUState GetState();
 volatile CPUState *GetStatePtr();  // this oddity is here instead of an extern declaration to easily be able to find all direct accesses throughout the code.