Cache error retry technique

Abstract

A method and apparatus is provided for enhanced error correction processing through a retry mechanism. When an L1 cache instruction line error is detected, either by a parity error detection process or by an ECC (error correcting code) or other process, the disclosed methodology will schedule an automatic retry of the event that caused the line error without re-booting the entire system. Thereafter, if the error remains present after a predetermined number of retries to load the requested data from L1 cache, then a second level of corrective action is undertaken. The second level corrective action includes accessing an alternate memory location, such as the L2 cache for example. If the state of the requested cache line is exclusive or shared, then an artificial L1 miss is generated for use in enabling an L2 access for the requested cache line. If the requested cache line still does not load from the L2 cache, the second level corrective methodology, after a selective number of retries, terminates and a machine check is generated to initiate a more extensive corrective or recovery action procedure. In an exemplary embodiment, a mechanism is illustrated for recovery from transient errors in an L1 cache load operation although the disclosed methodology may also be implemented partially or entirely in software and in any parity or other error detecting application.