DATA PROCESSING APPARATUS HAVING MEMORY PROTECTION UNIT

A data processor (100) has a memory operable to store data values; a memory protection unit (130) operable to associate memory attributes with portions of said memory and to identify a plurality of memory regions corresponding to respective address ranges of said memory. The memory protection unit is operable to associate with at least one of the plurality of memory regions (150) a respective memory region specifier comprising an attributes field (230) for defining a set of memory attributes associated with said memory region and a sub-region field (240) for holding a sub-region membership value. The sub-region membership value specifies, for each of a plurality of sub-regions of the memory region, whether respective sub-regions (160-1 to 160-8) are member sub-regions or non-member sub-regions such that said memory attributes are applied to said member sub-regions but are not applied to said non-member sub-regions.