Masking of architectural state associated with a realm

摘要

Processing circuitry (8) processes software processes at one of a plurality of exception levels and in one of a plurality of realms, each realm corresponding to a portion of at least one software process and being associated with a boundary exception level indicating a most privileged exception level at which the realm can be processed by the processing circuitry (8). In response to a realm exiting exception condition during processing of a given realm, where the exception condition is to be handled by an exception handler at a more privileged exception level than the boundary exception level of the given realm, the processing circuitry (8) performs state masking to make inaccessible, to software processes processed at a more privileged exception level than the boundary exception level, architectural state of a subset of registers selected depending on the boundary exception level of the given realm.