Operation system independent polled interface for extension BIOS (XBIOS) operations
AssigneeDell USA, L.P.
InventorJohn J. Pearce
Life of this patent
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Abstract
System management mode (SMM) is utilized, despite operating system security measures, by furnishing a polled interface for SMM. When an application program is to make an XBIOS call, the application program posts an XBIOS request in a storage. SMM is activated periodically by a timer and, during activation, checks the storage for XBIOS requests. When an XBIOS request is posted, SMM processes the request XBIOS command and leaves a response from the XBIOS call in the storage. The application program, which continually loops, monitors the storage and detects replacement of the XBIOS request by the XBIOS result to realize completion of an XBIOS call.
Claims14
A utility program operating on a computer system having a processor, a storage and a timer, the utility program comprising:
- a timer activating routine which enables the timer and sets a periodic timer interrupt interval to generate timer interrupts;
- an extension BIOS (XBIOS) module including a plurality of XBIOS routines, an XBIOS routine being activated by an XBIOS call;
- a continuously-looping application program which writes an activation pattern invoking an XBIOS request to the storage;
- a system management operating mode (SMM) which is activated by a timer interrupt, the SMM including a routine for checking the activation pattern in the storage and activating an XBIOS routine via an XBIOS call when the activation pattern is a designated pattern, the XBIOS routine writing a response to the storage.
A utility program operating on a computer system having a processor and a storage, the utility program comprising:
- an extension BIOS (XBIOS) module including a plurality of XBIOS routines, an XBIOS routine being activated by an XBIOS call;
- a continuously-looping application program which writes an activation pattern to the storage;
- a system management operating mode (SMM) which periodically polls the application program to determine when the activation pattern is written to storage, the SMM including a routine for checking the activation pattern in the storage and activating an XBIOS routine via an XBIOS call when the activation pattern is a designated pattern, the XBIOS routine writing a response to the storage.
A method of indirectly accessing XBIOS functionality of a processor that is protected by an operating system that prohibits direct system BIOS calls and direct system management mode (SMM) calls, the method comprising the steps of:
- simultaneously executing an application program and SMM operations by multiprogramming, the application program executing a plurality of instructions in a loop, the SMM being activated periodically by a timer;
- during application program execution, posting an XBIOS request in a storage in response to an application program instruction indicative of the XBIOS request;
- during SMM operations, checking the storage to detect an XBIOS request during SMM activation;
- when an XBIOS request is posted, processing the XBIOS command;
- upon termination of the XBIOS command processing, writing an XBIOS command response to the storage.
Dependencies are inferred from the claim text.