From: Will Deacon <will@kernel.org>
To: Julien Grall <julien.grall@arm.com>
Cc: linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, catalin.marinas@arm.com,
suzuki.poulose@arm.com, Dave.Martin@arm.com
Subject: Re: [PATCH] arm64: cpufeature: Export Armv8.6 Matrix feature to userspace
Date: Tue, 29 Oct 2019 11:36:07 +0000 [thread overview]
Message-ID: <20191029113606.GB12103@willie-the-truck> (raw)
In-Reply-To: <f58cb01f-4543-6041-df2d-7ca7ba887bc9@arm.com>
On Tue, Oct 29, 2019 at 11:26:41AM +0000, Julien Grall wrote:
> On 29/10/2019 11:15, Will Deacon wrote:
> > On Fri, Oct 25, 2019 at 06:10:56PM +0100, Julien Grall wrote:
> > > This patch provides support for reporting the presence of Armv8.6
> > > Matrix and its optional features to userspace.
> >
> > Are you sure this is 8.6 and not earlier?
>
> This was introduced by Armv8.6 see [1] but allowed to be used by Armv8.2 and
> onwards.
That doesn't mean an awful lot though, especially then the features are
referred to in the docs as things like "ARMv8.2-F64MM".
> > > @@ -227,6 +229,12 @@ infrastructure:
> > > +------------------------------+---------+---------+
> > > | Name | bits | visible |
> > > +------------------------------+---------+---------+
> > > + | F64MM | [56-59] | y |
> > > + +------------------------------+---------+---------+
> > > + | F32MM | [52-55] | y |
> > > + +------------------------------+---------+---------+
> > > + | I8MM | [44-47] | y |
> > > + +------------------------------+---------+---------+
> >
> > Urgh, we're inconsistent in our bitfields. Some are [lo-hi] whilst others
> > are [hi-lo]. Please can you fix that in a preparatory patch? I prefer
> > [hi-lo] and it matches the arch docs.
>
> Sure.
Thanks.
Will
next prev parent reply other threads:[~2019-10-29 11:36 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-25 17:10 [PATCH] arm64: cpufeature: Export Armv8.6 Matrix feature to userspace Julien Grall
2019-10-29 11:15 ` Will Deacon
2019-10-29 11:26 ` Julien Grall
2019-10-29 11:36 ` Will Deacon [this message]
2019-10-29 15:32 ` Julien Grall
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