From: Dave Martin <Dave.Martin@arm.com>
To: Mark Brown <broonie@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Shuah Khan <skhan@linuxfoundation.org>,
linux-arm-kernel@lists.infradead.org,
linux-kselftest@vger.kernel.org
Subject: Re: [PATCH v1 1/3] kselftest/arm64: Provide a helper binary and "library" for SVE RDVL
Date: Wed, 28 Jul 2021 11:45:11 +0100 [thread overview]
Message-ID: <20210728104511.GD1724@arm.com> (raw)
In-Reply-To: <20210728102035.GB4670@sirena.org.uk>
On Wed, Jul 28, 2021 at 11:20:35AM +0100, Mark Brown wrote:
> On Wed, Jul 28, 2021 at 10:41:30AM +0100, Dave Martin wrote:
> > On Tue, Jul 27, 2021 at 07:06:47PM +0100, Mark Brown wrote:
> > > SVE provides an instruction RDVL which reports the currently configured
> > > vector length. In order to validate that our vector length configuration
> > > interfaces are working correctly without having to build the C code for
>
> > > +.globl rdvl_sve
> > > +rdvl_sve:
> > > + rdvl x0, #1
> > > + ret
> >
> > This works, but can we use an ACLE intrinsic for this? I'm pretty GCC
> > and LLVM have been up to date with that stuff for some time, though
> > you'd have to check with the compiler folks.
>
> If we put SVE into C source files we need to build the C code with SVE
> support enabled, I felt it was safer to avoid any possibility that we
> might get some interference with the tests due to interactions with SVE
> code generated by the compiler. It should be fine, but it's even easier
> to not have to think about it at all.
Good point, stick with the out-of-line asm in that case.
(Also saves having to find out about the intrinsics!)
Cheers
---Dave
next prev parent reply other threads:[~2021-07-28 10:46 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-27 18:06 [PATCH v1 0/3] kselftest/arm64: Vector length configuration tests Mark Brown
2021-07-27 18:06 ` [PATCH v1 1/3] kselftest/arm64: Provide a helper binary and "library" for SVE RDVL Mark Brown
2021-07-28 9:41 ` Dave Martin
2021-07-28 10:20 ` Mark Brown
2021-07-28 10:45 ` Dave Martin [this message]
2021-07-27 18:06 ` [PATCH v1 2/3] kselftest/arm64: Validate vector lengths are set in sve-probe-vls Mark Brown
2021-07-28 9:41 ` Dave Martin
2021-07-28 11:07 ` Mark Brown
2021-07-28 11:35 ` Dave Martin
2021-07-27 18:06 ` [PATCH v1 3/3] kselftest/arm64: Add tests for SVE vector configuration Mark Brown
2021-07-28 9:41 ` Dave Martin
2021-07-28 12:59 ` Mark Brown
2021-07-28 13:44 ` Dave Martin
2021-07-28 16:29 ` Mark Brown
2021-07-28 16:37 ` Dave Martin
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