Add user access API for linux.

On linux userspace virtual == user == phys addresses.  Physical
addresses also being the same is wrong, but there is no general way of
converting userspace addresses to physical as what appears to be
contiguous in userspace is physically fragmented.  Currently only the
DMA memory is special-cased, but its conversion to bus addresses is
done in phys_to_bus.  This is known to break virtio as it is passing
phys addresses to the virtual device.

Signed-off-by: Piotr Jaroszyński <p.jaroszynski@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

Signed-off-by: Piotr Jaroszyński <p.jaroszynski@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

Add a new network driver that consumes the EFI Simple Network
Protocol.  Also add a bus driver that can find the Simple Network
Protocol that iPXE was loaded from; the resulting behavior is similar
to the "undionly" driver for BIOS systems.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

Add FILE_LICENCE declarations to almost all files that make up the
various standard builds of gPXE.

bytes of useless zeroes in the final image.

by PXE and NBI) and UNDI packets (as used by undinet and UNDI).

UNDI stack.

typical build will now include 880 bytes of PCI support code, compared to
2327 bytes in Etherboot 5.4.

(There is a slight cost of around 5 extra bytes per access to a
non-constant config space address; this should be an overall win.
Driver-specific accesses will usually be to constant addresses, for
which there is no additional cost.)

Yes, you really can do it in 65 bytes.