Method and apparatus for seeding differences in lock-stepped processors
AssigneeHewlett-Packard Development Company, L.P.
InventorsKevin David Safford, Jeremy P. Petsinger
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Abstract
An apparatus, and a corresponding method, are used for seeding differences in lock stepped processors, the apparatus implemented on two or more processors operating in a lock step mode, wherein each of the two or more processors comprise a processor-specific resource operable to seed the differences, a processor logic to execute a code sequence, wherein an identical code sequence is executed by the processor logic of each of the two or more processors, and an output to provide a result of execution of the code sequence. The processor outputs, based on execution of the code sequence is provided to a lock step logic operable to read and compare the output of each of the two or more processors.
Claims13
An apparatus for seeding differences in lock stepped processors, comprising:
- two or more processors operating in a lock step mode, wherein each of the two or more processors comprise:
- read-only machine specific register (MSR) operable to seed the differences,
- processor logic to execute a code sequence, wherein an identical code sequence is executed by the processor logic of each of the two or more processors, and
- an output to provide a result of execution of the code sequence;
- and
- a lock step logic operable to read and compare the output of each of the two or more processors.
A method for seeding differences in lock stepped processors, comprising:
- loading a code sequence;
- and
- in each of two or more processors operating in lock step, executing the code sequence, comprising:
- reading a read-only machine specific register (MSR),
- determining a conditional state, and
- executing an instruction based on the conditional state.
A method for seeding differences in lock stepped processors, comprising:
- identifying a first lock stepped processor based on a value unique to the first lock-stepped processor;
- executing a first instruction based on the identifying step, comprising reading a read-only machine specific register (MSR), whereby a first output is created;
- and
- comparing the first output to one or more subsequent outputs generated by execution of subsequent instructions on subsequent lock stepped processors, wherein if any of the first and the subsequent outputs differ, a loss of lock step is indicated.
Dependencies are inferred from the claim text.