Well semolina is durum wheat and there for contains gluten.
You have to find gluten free flour instead, it all depends on what you are going to use it for, sometimes you can use gluten free polenta ( glutenfree polenta is done in a mill that doesnt mill any grain containing gluten), almond meal or hazelnut meal. It all depends on what you are making. But make sure it says gluten free on the box.
For the love of Cheese!