The main focus of current research in Trusted Operating Systems (TOS) is on the enhanced access control of reference monitors which, in turn, control the individual operations on a given access instance. However, many real-life runtime attacks involve behavioral semantics. We have proposed an extended reference monitor to support both access and behavior controls. This results in a sequence of operations which are also of concern in security enforcement. This paper presents a policy language for the extended reference monitor. Our policy language is based on Domain and Type Enforcement (DTE) and Role-Based Access Control (RBAC). Permission is defined as an event and a state of behavior is represented as a fluent to be accorded with the convention of Event Calculus (EC). Behavior policies can be expressed with the EC style syntax as well as access control policies.