linux-kernel - Re: [PATCH] kselftest/arm64: Include kernel mode NEON in fp-stress

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Date: Wed, 12 Jun 2024 17:08:28 +0100
From: Catalin Marinas <catalin.marinas@....com>
To: Will Deacon <will@...nel.org>,
	Shuah Khan <shuah@...nel.org>,
	Mark Brown <broonie@...nel.org>
Cc: Johannes Nixdorf <mixi@...dowice.org>,
	Ard Biesheuvel <ardb@...nel.org>,
	Dave Martin <Dave.Martin@....com>,
	linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-kselftest@...r.kernel.org
Subject: Re: [PATCH] kselftest/arm64: Include kernel mode NEON in fp-stress

On Tue, 21 May 2024 19:18:26 +0100, Mark Brown wrote:
> Currently fp-stress only covers userspace use of floating point, it does
> not cover any kernel mode uses.  Since currently kernel mode floating
> point usage can't be preempted and there are explicit preemption points in
> the existing implementations this isn't so important for fp-stress but
> when we readd preemption it will be good to try to exercise it.
> 
> When the arm64 accelerated crypto operations are implemented we can
> relatively straightforwardly trigger kernel mode floating point usage by
> using the crypto userspace API to hash data, using the splice() support
> in an effort to minimise copying.  We use /proc/crypto to check which
> accelerated implementations are available, picking the first symmetric
> hash we find.  We run the kernel mode test unconditionally, replacing the
> second copy of the FPSIMD testcase for systems with FPSIMD only. If we
> don't think there are any suitable kernel mode implementations we fall back
> to running another copy of fpsimd-stress.
> 
> [...]

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

[1/1] kselftest/arm64: Include kernel mode NEON in fp-stress
      https://git.kernel.org/arm64/c/d5859510d35d

-- 
Catalin