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References: <20230228215435.3366914-1-heiko@sntech.de>
In-Reply-To: <20230228215435.3366914-1-heiko@sntech.de>
From:   Guo Ren <guoren@kernel.org>
Date:   Wed, 1 Mar 2023 10:21:43 +0800
Message-ID: <CAJF2gTSG23qMp6UuF_zrHY-QvVCR4BNm2vA088BJTe3rF0vUkg@mail.gmail.com>
Subject: Re: [PATCH RFC 0/2] RISC-V: T-Head vector handling
To:     Heiko Stuebner <heiko@sntech.de>
Cc:     palmer@dabbelt.com, linux-riscv@lists.infradead.org,
        samuel@sholland.org, christoph.muellner@vrull.eu,
        conor.dooley@microchip.com, linux-kernel@vger.kernel.org,
        Heiko Stuebner <heiko.stuebner@vrull.eu>
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On Wed, Mar 1, 2023 at 5:54=E2=80=AFAM Heiko Stuebner <heiko@sntech.de> wro=
te:
>
> From: Heiko Stuebner <heiko.stuebner@vrull.eu>
>
> As is widely known the T-Head C9xx cores used for example in the
> Allwinner D1 implement an older non-ratified variant of the vector spec.
>
> While userspace will probably have a lot more problems implementing
> support for both, on the kernel side the needed changes are actually
> somewhat small'ish and can be handled via alternatives somewhat nicely.
>
> With this patchset I could run the same userspace program (picked from
> some riscv-vector-test repository) that does some vector additions on
> both qemu and a d1-nezha board. On both platforms it ran sucessfully and
> even produced the same results.
Great! Thx.

>
>
> As can be seen in the todo list, there are 2 places where the changed
> SR_VS location still needs to be handled in the next revision
> (assembly + ALTERNATIVES + constants + probably stringify resulted in
>  some grey hair so far already)
>
>
> ToDo:
> - follow along with the base vector patchset
> - handle SR_VS access in _save_context and _secondary_start_sbi
>
>
> Heiko Stuebner (2):
>   RISC-V: define the elements of the VCSR vector CSR
>   RISC-V: add T-Head vector errata handling
>
>  arch/riscv/Kconfig.erratas           |  13 +++
>  arch/riscv/errata/thead/errata.c     |  32 ++++++
>  arch/riscv/include/asm/csr.h         |  31 +++++-
>  arch/riscv/include/asm/errata_list.h |  62 +++++++++++-
>  arch/riscv/include/asm/vector.h      | 139 +++++++++++++++++++++++++--
>  5 files changed, 261 insertions(+), 16 deletions(-)
>
> --
> 2.39.0
>


--=20
Best Regards
 Guo Ren