Patent ID: 7434264
Filing Date: 2008-10-07
Classification: G06F

Abstract:
1. A method for providing peripheral access protection in a data processing system having a bus, the method comprising: initiating a bus access by a first bus master which requires access to a peripheral, the first bus master operating at a privilege level selected from a plurality of privilege levels; providing a privilege indicator which is associated with the bus access, the privilege indicator indicating the privilege level selected from the plurality of privilege levels; providing a privilege level modifier corresponding to the first bus master, wherein the privilege level modifier is stored in a register field, and wherein the privilege level modifier corresponds to the first bus master only; and selectively adjusting the privilege indicator to indicate another privilege level of the plurality of privilege levels based upon a value of the privilege level modifier in order to produce a selectively adjusted privilege indicator, wherein the selectively adjusting comprises: using the selectively adjusted privilege indicator rather than the privilege indicator in determining if the bus access to the peripheral will be allowed, while the first bus master continues to operate at the privilege level selected from the plurality of privilege levels.