You haven't put the mileage on, but oil smoke on start up is due obviously to oil in the combustion chamber, this is either residue from the bore, or more likely, oil running down the valve stems and into the cylinder that way, that is due to wear on the valve stem seals, caused by high mileage or a lack of good oil in the engine, or heat. Give it an oil change and see if it improves. If it doesn't, you need to look more closely (read expensive) at things.