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Cache lock down in ARM Cortex-A7

Anshul

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.

Parents
  • 0 in reply to Peter Harris

    Hi Peter,

       Thanks a lot. I misunderstand about the cache eviction and I also find description in TrustZone whitepaper according to your explanation.

    Caches

         It is a desirable feature of any high performance design to support data of both security states in the caches. This removes the need for a cache flush when switching between worlds, and enables high performance software to communicate over the world boundary. To enable this the L1, and where applicable level two and beyond, processor caches have been extended with an additional tag bit which records the security state of the transaction that accessed the memory.

         The content of the caches, with regard to the security state, is dynamic. Any non-locked down cache line can be evicted to make space for new data, regardless of its security state. It is possible for a Secure line load to evict a Non-secure line, and for a Non-secure line load to evict a Secure line.

    Best Regards.

Reply
  • 0 in reply to Peter Harris

    Hi Peter,

       Thanks a lot. I misunderstand about the cache eviction and I also find description in TrustZone whitepaper according to your explanation.

    Caches

         It is a desirable feature of any high performance design to support data of both security states in the caches. This removes the need for a cache flush when switching between worlds, and enables high performance software to communicate over the world boundary. To enable this the L1, and where applicable level two and beyond, processor caches have been extended with an additional tag bit which records the security state of the transaction that accessed the memory.

         The content of the caches, with regard to the security state, is dynamic. Any non-locked down cache line can be evicted to make space for new data, regardless of its security state. It is possible for a Secure line load to evict a Non-secure line, and for a Non-secure line load to evict a Secure line.

    Best Regards.

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