A turbine (32) section of a turbocharger (30) includes a turbine wheel (37) disposed in a turbine housing (33), the turbine housing (33) defining a gas inlet (34), a volute configured to direct gas from the inlet (34) to the turbine (32) wheel, and a gas outlet. A rotary diverter valve (100, 200) is disposed in the gas inlet (34) upstream of the volute, and provides three modes of controlling exhaust gas flow about the turbocharger (30).