sys_spu: Fix warning and theoretical bug

rpcs3/Emu/Cell/SPUThread.cpp

@@ -1603,6 +1603,7 @@ void spu_thread::cpu_return()
 
 		if (ensure(group->running)-- == 1)
 		{
+			u32 last_stop = 0;
 			{
 				lv2_obj::notify_all_t notify;
 				std::lock_guard lock(group->mutex);
@@ -1632,7 +1633,17 @@ void spu_thread::cpu_return()
 					exit_status.set_value(last_exit_status);
 				}
 
-				group->stop_count++;
+				last_stop = group->stop_count;
+
+				if (last_stop == umax)
+				{
+					// Restart with some high count to preserve some meaning
+					group->stop_count = 1000;
+				}
+				else
+				{
+					group->stop_count++;
+				}
 
 				if (const auto ppu = std::exchange(group->waiter, nullptr))
 				{
@@ -1646,6 +1657,12 @@ void spu_thread::cpu_return()
 
 			// Notify on last thread stopped
 			group->stop_count.notify_all();
+
+			// Wait for terminators manually if needed (ensuring they quit before value-wrapping)
+			while (last_stop == umax && group->wait_term_count)
+			{
+				std::this_thread::yield();
+			}
 		}
 		else if (status_npc.load().status >> 16 == SYS_SPU_THREAD_STOP_THREAD_EXIT)
 		{

rpcs3/Emu/Cell/lv2/sys_spu.cpp

@@ -1352,7 +1352,8 @@ error_code sys_spu_thread_group_terminate(ppu_thread& ppu, u32 id, s32 value)
 	if (group->set_terminate)
 	{
 		// Wait for termination, only then return error code
-		const u64 last_stop = group->stop_count;
+		const u32 last_stop = group->stop_count;
+		group->wait_term_count++;
 		lock.unlock();
 		short_sleep(ppu);
 
@@ -1361,6 +1362,7 @@ error_code sys_spu_thread_group_terminate(ppu_thread& ppu, u32 id, s32 value)
 			group->stop_count.wait(last_stop);
 		}
 
+		group->wait_term_count--;
 		return CELL_ESTAT;
 	}
 
@@ -1414,7 +1416,8 @@ error_code sys_spu_thread_group_terminate(ppu_thread& ppu, u32 id, s32 value)
 	group->join_state = SYS_SPU_THREAD_GROUP_JOIN_TERMINATED;
 
 	// Wait until the threads are actually stopped
-	const u64 last_stop = group->stop_count;
+	const u32 last_stop = group->stop_count;
+	group->wait_term_count++;
 	lock.unlock();
 	short_sleep(ppu);
 
@@ -1423,6 +1426,7 @@ error_code sys_spu_thread_group_terminate(ppu_thread& ppu, u32 id, s32 value)
 		group->stop_count.wait(last_stop);
 	}
 
+	group->wait_term_count--;
 	return CELL_OK;
 }
 

rpcs3/Emu/Cell/lv2/sys_spu.h

@@ -289,7 +289,8 @@ struct lv2_spu_group
 	atomic_t<s32> exit_status; // SPU Thread Group Exit Status
 	atomic_t<u32> join_state; // flags used to detect exit cause and signal
 	atomic_t<u32> running = 0; // Number of running threads
-	atomic_t<u64> stop_count = 0;
+	atomic_t<u32> stop_count = 0;
+	atomic_t<u32> wait_term_count = 0; 
 	u32 waiter_spu_index = -1; // Index of SPU executing a waiting syscall
 	class ppu_thread* waiter = nullptr;
 	bool set_terminate = false;