Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <e187cda4edf0a3186e7caae8ed285e2564742f26.camel@xry111.site>
Subject: Re: [PATCH] LoongArch: Clean useless vcsr in loongarch_fpu.
From:   Xi Ruoyao <xry111@xry111.site>
To:     huqi <huqi@loongson.cn>, WANG Xuerui <kernel@xen0n.name>,
        Huacai Chen <chenhuacai@kernel.org>,
        Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc:     loongarch@lists.linux.dev, linux-kernel@vger.kernel.org
Date:   Mon, 04 Jul 2022 17:58:57 +0800
In-Reply-To: <7904571e-3ef4-5841-497d-6796c8c36c52@loongson.cn>
References: <20220704061402.683762-1-huqi@loongson.cn>
         <1470d272-e148-c600-f759-a1e2dac776e1@xen0n.name>
         <7904571e-3ef4-5841-497d-6796c8c36c52@loongson.cn>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
User-Agent: Evolution 3.44.3 
MIME-Version: 1.0
Precedence: bulk

On Mon, 2022-07-04 at 17:27 +0800, huqi wrote:

>=20
> > The original code was written with future LSX/LASX support in mind;=20
> > the code is dead currently, but expected to get utilized Soon (TM).
> >=20
> > So, I'd like to confirm if future LoongArch models would *not* feature=
=20
> > LSX/LASX in its current form, and that the Loongson Corporation is not=
=20
> > going to upstream LSX/LASX support, given you are apparently a=20
> > Loongson employee with the first-hand information? We'd like to avoid=
=20
> > code churn in general, so if the LSX/LASX support is to be eventually=
=20
> > mainlined, removing them now would only lead to them being introduced=
=20
> > later.
>=20
> `vcsr` is removed because it has been removed in hardware. What's more,=
=20
> it will not be used to support LSX/LASX in the future.

It would be better to add this information into the commit message.  Is
it already removed in 3A5000?  On my machine "movfcsr2gr $a0, $r16"
produces SIGILL (but maybe it's because LSX is not enabled via the EUEN
register).

--=20
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University