Re: [PATCH v1 1/3] arm64/sve: Split _sve_flush macro into separate Z, P and FFR flushes

On Mon, May 10, 2021 at 04:47:23PM +0100, Dave Martin wrote:

On Mon, May 10, 2021 at 04:22:53PM +0100, Mark Brown wrote:

quoted

On Mon, May 10, 2021 at 03:57:11PM +0100, Dave P Martin wrote:

quoted

quoted

If not, can we keep these combined?  We could either keep the name
sve_flush_p (since the FFR is a predicate register, if a weird kind of
one), or go with something more descriptive such as sve_flush_p_and_ffr.

quoted

Not right now but I do expect to build on this in the not too distant
future.

OK, but due to the fact that we need to dirty a P-register in order to
zero the FFR, these still don't feel like independent operations.

Indeed, like I said I got confused by the way the macros end up being
written when I originally wrote this.

Can we control the clearing of the FFR (or not) with an argument to a
combined macro?

It's an option, I'm poking around with how to do it.