I can think of a few ways how you could do this, but I am kind of mystified as to why you would.

It seems to be rather a Bad Idea to me. For example, if you are just making a blind jump back to the beginning, how are you going to ensure you don't wind up back in the same subroutine and loop forever. Global variables? <shudder>

Anyway, maybe you could tell us a little more about what you are trying to accomplish, so we can help you find a Better Way.