1. In a computer system having a central processing unit and a software identity register, a method comprising: executing an atomic operation to set an identity of a piece of software into the software identity register, wherein if the atomic operation completes correctly, the software identity register contains the identity of the piece of software and if the atomic operation fails to complete correctly, the software identity register contains a value other than the identity of the piece of software; and examining the software identity register to verify the identity of the piece of software.