Re: [PATCH] xtensa: don't clear cpenable unconditionally on release

On Mon, Nov 26, 2018 at 4:47 PM Max Filippov jcmvbkbc@gmail.com wrote:

fast_coprocessor exception handler expects that the coprocessor owner task never gets the "coprocessor disabled" exception for a coprocessor that is marked as enabled in the thread_info::cpenable. If that happens it will reload potentially outdated context from the thread_info structure into the coprocessor registers.

After looking at it some more I see that the above is not true. It will flush current coprocessor context to the thread_info and then load it back from there. No correctness issue, but some extra work that can be avoided.