US Patent 7930738 Method and apparatus for secure execution of code

One embodiment of the present invention provides a system that facilitates secure execution of code. During operation, the system executes a section of code. Upon executing an instruction that raises a privilege of the section of code, the system checks if the section of code is trusted, wherein trusted code is allowed to raise the privilege and non-trusted code is not allowed to raise the privilege. If so, the system raises the privilege of the section of code and executes the section of code. After the section of code is executed, the system then lowers the privilege of the section of code.