Via came up with a nifty feature on their "Nehemiah" generation of the 
C3 CPU: the xstore instruction.  If the 'rep' prefix is not present, the 
instruction stores 0/1/2/4/8 bytes of random data to a memory location.

This xstore instruction forms the basis of this third patch, which adds 
support for the Via RNG to the newly-modular hw_random driver.

Note that since xstore is a new instruction, GNU binutils does not 
support it.  We must use gcc inline asm to hand-code the machine 
language instruction in hexidecimal.  Eventually I will get around to 
patching GNU binutils to support xstore natively, but even then we won't 
want to force users to update their binutils to bleeding-edge-latest, I 
don't think...

Review from x86 experts is especially appreciated here, as I am from an 
x86 expert myself.