Transparent software emulation as an alternative to hardware bus lock
AssigneeHewlett-Packard Development Company, L.P.
InventorRobert J Brooks
Life of this patent
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Abstract
A method and apparatus for emulating hardware bus lock in a multi-architecture computer system includes a fault handler that acquires a semaphore reserved for bus lock and a semaphore that limits access to a page table. The fault handler includes an emulation module that sets a mode bit to prevent the bus lock and allows re-execution of the instruction that caused a request for a hardware bus lock. Using this method, the fault handler ensures a minimum disruption to operation of the computer system by restricting access to the least amount of computer system resources.
Claims14
A method for emulating hardware bus lock in a computer system, comprising:
- acquiring a bus lock semaphore reserved for bus lock emulation;
- acquiring a page table semaphore;
- setting a mode bit that defeats fault-on-lock-attempt behavior;
- invalidating relevant page table entries;
- executing an instruction;
- and
- releasing mode bit and the bus lock and page table semaphores.
A method for emulating a hardware bus lock in a computer system, comprising:
- receiving a hardware bus lock request from a device in the computer system;
- generating a fault in response to the hardware bus lock request;
- setting a mode bit that defeats fault-on-lock-attempt behavior, thereby preventing a hardware bus lock;
- processing the fault in a fault handler;
- and
- releasing the mode bit after the processing.
An apparatus for emulating hardware bus lock in a computer system, comprising:
- a fault handler that, in response to a device requesting a hardware bus lock, acquires a bus lock semaphore and a page table semaphore;
- and
- an emulation module coupled to the fault handler that invalidates entries in a page table, wherein the fault handler sets a mode bit that defeats fault-on-lock-attempt behavior to prevent hardware bus lock, releases the mode bit and the semaphores after execution of an instruction by the device.
Dependencies are inferred from the claim text.