A secure promotion mechanism promotes a current privilege level of a
processor in a computer system. The current privilege level controls
application instruction execution in the computer system by controlling
accessibility to system resources. An operating system performs a
privilege promotion instruction, which is stored in a first page of
memory not writeable by an application instructions at a first privilege
level. The privilege promotion instruction reads a stored previous
privilege level state, compares the read previous privilege level state
to the current privilege level, and if the previous privilege level state
is equal to or less privileged than the current privilege level, promotes
the current privilege level to a second privilege level which is higher
than the first privilege level.