I want to improve the performance of some game in our platform. I have heard of cache lock down feature to achieve performance improvement. Please suggest me how to use this feature in ARM Cortex-A7 for performance improvement.
While I haven't examine it in depth, it seems that the TLB cache seems to persist Secure accesses for a long time. I copied the normal world boot code via secure world and do not flush the secure TLB. After one day of use, the initial secure copies are still present in the TLB cache. Either the normal world OS is avoiding section entries or it seems that secure TLB entries on the Cortex-A5 persist for some time. I also have a 'NULL' TLB entry from the secure OS, so it has been interesting to dump the TLBs. I definitely don't think the eviction of secure world entries is 'standard'. Most definitely, the normal world OS accesses the same boot sections and no normal world entries are allocated.
Also, the eviction of the secure world lines makes them susceptible to the same attacks discussed in this hyper-threading paper.