Patent ID: 7996659
Filing Date: 2011-08-09
Classification: G06F

Abstract:
1. A computer-implemented method comprising: receiving a call to a system routine made from any of a plurality of operation modes configured to execute within a given instruction set architecture, the plurality of operation modes including an unprivileged application mode and a privileged supervisor mode, the unprivileged application mode initiating the call from an application program configured to execute in the given instruction set architecture and the privileged supervisor mode initiating the call from an operating system configured to execute in the given instruction set architecture, the method further comprising the following steps in the following order: determining an execution context of the operation mode from which the call was made; if the execution context includes the unprivileged application mode, then: if the execution context is a privileged supervisor mode, then: if the execution context is any of a plurality of other privileged modes, then: