PROTECTED EXCEPTION HANDLING

A data processing system for processing data comprising: ownership circuitry to enforce ownership rights of memory regions, a given more privileged state memory region having a given owning process specified from among a plurality of processes, said given owning process having exclusive rights to control access to said given memory region; and context switching circuitry responsive to receipt of an interrupt to trigger a context switch from a first active process to a second active process whereby one or more items of state for use in restarting said first process is saved to one or more context data memory regions owned by said first process and one or more items of state accessible to said second process and dependent upon processing by said first process is overwritten prior to commencing execution of said second process.