1. A method of instruction cache (I-cache) management, comprising: providing security critical instructions to indicate a security critical code section for an I-cache; and implementing an I-cache locking policy to prevent unauthorized eviction and replacement of security critical instructions in the I-cache; wherein implementing the I-cache locking policy further includes: for each I-cache entry: providing a status value indicating that an instruction in the entry is security critical or non-critical; and during the selection of I-cache entries to be evicted, checking said status value for each entry to be evicted and selecting entries with non-critical instructions to evict from the I-cache.