Re: [PATCH] arm64/sme: Optimise SME exit on syscall entry

From: Catalin Marinas
Date: Thu Jan 12 2023 - 13:19:27 EST


On Tue, 10 Jan 2023 19:34:36 +0000, Mark Brown wrote:
> Our ABI says that we exit streaming mode on syscall entry. Currently we
> check if we are in streaming mode before doing this but since we have a
> SMSTOP SM instruction which will clear SVCR.SM in a single atomic operation
> we can save ourselves the read of the system register and check of the flag
> and just unconditionally do the SMSTOP SM. If we are not in streaming mode
> it results in a noop change to SVCR, if we are in streaming mode we will
> exit as desired.
>
> [...]

Applied to arm64 (for-next/sme), thanks!

[1/1] arm64/sme: Optimise SME exit on syscall entry
https://git.kernel.org/arm64/c/b2482807fbd4

--
Catalin