Processor and data processing method with non-hierarchical computer security enhancements for context states

Abstract

Disclosed are a processor and processing method that provide non-hierarchical computer security enhancements for context states. The processor can comprise a context control unit that uses context identifier tags associated with corresponding contexts to control access by the contexts to context information (i.e., context states) contained in the processor's non-stackable and/or stackable registers. For example, in response to an access request, the context control unit can grant a specific context access to a register only when that register is tagged with a specific context identifier tag. If the register is tagged with another context identifier tag, the contents of the specific register are saved in a context save area of memory and the previous context states of the specific context are restored to the specific register before access can be granted. The context control unit can also provide such computer security enhancements while still facilitating authorized cross-context and/or cross-level communications.