Data processing system with peripheral access protection and method therefor

A data processing system, comprising:

• a first bus master;
• a peripheral;
• a privilege indicator;
• an adjusted privilege indicator;
• a first storage circuit which stores a first privilege level modifier corresponding to the first bus master;
• and
• control circuitry, coupled to the first bus master, to the peripheral, to the privilege indicator, to the adjusted privilege indicator, and to the first storage circuit, said control circuitry receives the privilege indicator and selectively adjusts the privilege indicator based upon the first privilege level modifier, said control circuitry provides the adjusted privilege indicator.

A method for providing peripheral access protection in a data processing system, comprising:

• providing a first bus master;
• providing a second bus master;
• initiating a first bus access which requires access to a peripheral;
• providing a first privilege indicator which is associated with the first bus access;
• providing a first privilege level modifier;
• selectively adjusting the first privilege indicator based upon the first privilege level modifier in order to produce a first selectively adjusted privilege indicator;
• initiating a second bus access which requires access to the peripheral;
• providing a second privilege indicator which is associated with the second bus access;
• providing a second privilege level modifier;
• and
• selectively adjusting the second privilege indicator based upon the second privilege level modifier in order to produce a second selectively adjusted privilege indicator.

A method for providing peripheral access protection in a data processing system having a bus, the method comprising:

• initiating a bus access which requires access to a peripheral;
• providing at least one trust attribute corresponding to a first bus master, wherein the at least one trust attribute is independent of a supervisor/user attribute;
• and
• using the at least one trust attribute to determine whether the first bus master is a trusted bus master for the bus access.