Are bilinear, trilinear and quadrilinear texture sampling done in hardware?

Apologies for cross posting this from the OpenGL forums, but i think this may be the more appropriate place for it.

I’ve heard that bilinear texture sampling is done in hardware, is that true?

If so, how about trilinear and quadrilinear (or higher)? Are they also done in hardware? or does the driver do multiple texture reads behind the scenes and do the appropriate interpolations?

If they are all implemented in hardware, what is the highest order linear sampling that is available in modern hardware?