When a body rolls without sliding up an inclined plane, the frictional force is:

Since the body rolls without sliding, So ap = 0, up = 0 and v = ωr, a = αr Since the body's acceleration a is downward parallel to the plane, therefore angular acceleration of the body must be in anticlockwise a sense. That means the friction must act up the plane to produce an anticlockwise torque to produce anticlockwise angular acceleration.