Systems and methods for retiring and unretiring cache lines

Abstract

The systems and methods described herein may provide a flush-retire instruction for retiring 'bad' cache locations (e.g., locations associated with persistent errors) to prevent their allocation for any further accesses, and a flush-unretire instruction for unretiring cache locations previously retired. These instructions may be implemented as hardware instructions of a processor. They may be executable by processes executing in a hyper-privileged state, without the need to quiesce any other processes. The flush-retire instruction may atomically flush a cache line implicated by a detected cache error and set a lock bit to disable subsequent allocation of the corresponding cache location. The flush-unretire instruction may atomically flush an identified cache line (if valid) and clear the lock bit to re-enable subsequent allocation of the cache location. Various bits in the encodings of these instructions may identify the cache location to be retired or unretired in terms of the physical cache structure.