Combine garlic, oregano, olive oil, mustard, salt and pepper. Mix until blended into a paste. Using a spatula or hands, rub garlic mixture all over pork, massaging into meat.
Place pork roast in baking pan and roast uncovered in preheated oven. Roast 20 to 30 minutes per pound until internal temperature reaches 145 degrees F. using a meat thermometer. Remove from oven. Cover loosely with foil and let stand 10 minutes before slicing.