Apparatus and method for managing capabilities

A method of operating an apparatus to track capabilities for revocation, comprising:

• employing processing circuitry to perform operations during which access requests to memory are generated, wherein the processing circuitry generates memory addresses for the access requests using capabilities, where each capability is configured to indicate a pointer value and constraining information used to constrain access to memory using memory addresses derived from the pointer value;
• storing a marker indication field in association with each capability to provide a marker value used to distinguish between static capabilities used to access statically allocated memory and dynamic capabilities used to access dynamically allocated memory;
• maintaining, using capability tracking circuitry, a tracking structure providing a tracking field for each of a plurality of memory regions;
• and
• in response to at least one capability being written to a given memory region amongst the plurality of memory regions, determining, in dependence on whether the marker value of the marker indication field associated with said at least one capability and used to distinguish between static and dynamic capabilities indicates that writing of the associated capability to memory is to be tracked by the capability tracking circuitry to facilitate subsequent revocation of that associated capability, whether to set the tracking field for the given memory region.

A non-transitory computer readable storage medium having stored thereon a program for controlling a host data processing apparatus to provide an instruction execution environment, the program comprising:

• processing program logic to perform operations during which access requests to memory are generated, wherein the processing program logic is configured to generate memory addresses for the access requests using capabilities, where each capability is configured to indicate a pointer value and constraining information used to constrain access to memory using memory addresses derived from the pointer value, and wherein a marker indication field is stored in association with each capability to provide a marker value used to distinguish between static capabilities used to access statically allocated memory and dynamic capabilities used to access dynamically allocated memory;
• and
• capability tracking program logic to maintain a tracking structure providing a tracking field for each of a plurality of memory regions, wherein in response to at least one capability being written to a given memory region amongst the plurality of memory regions, the capability tracking program logic is configured to determine, in dependence on whether the marker value of the marker indication field associated with said at least one capability and used to distinguish between static and dynamic capabilities indicates that writing of the associated capability to memory is to be tracked by the capability tracking circuitry to facilitate subsequent revocation of that associated capability, whether to set the tracking field for the given memory region.