http://www.uefi.org/about/
Q: How is UEFI implemented on a computer system?
A: UEFI is an interface. It can be implemented on top of a traditional BIOS (in which case it supplants the traditional "INT" entry points into BIOS) or on top of non-BIOS implementations.
So in a sooner or later future I guess that Linux has to learn how to set up itself to such hardware too?Q: Can anyone build their own Unified EFI implementations?
A: Yes. UEFI expect BIOS vendors, OS vendors and add-in card vendors to all implement products based on the Unified EFI Specification.