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From:   Evan Green <evan@rivosinc.com>
Date:   Fri, 7 Apr 2023 16:13:23 -0700
Message-ID: <CALs-HstVAGX476SGi_+ct7xxWrBeSE=nGVqckGjm9xo06K-Mww@mail.gmail.com>
Subject: Re: [PATCH v5 2/6] RISC-V: Add a syscall for HW probing
To:     Paul Walmsley <paul@pwsan.com>
Cc:     Palmer Dabbelt <palmer@rivosinc.com>, slewis@rivosinc.com,
        vineetg@rivosinc.com, heiko@sntech.de,
        Conor Dooley <conor@kernel.org>,
        Conor Dooley <conor.dooley@microchip.com>,
        Heiko Stuebner <heiko.stuebner@vrull.eu>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Andrew Bresticker <abrestic@rivosinc.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Bagas Sanjaya <bagasdotme@gmail.com>,
        Celeste Liu <coelacanthus@outlook.com>,
        Guo Ren <guoren@kernel.org>, Jonathan Corbet <corbet@lwn.net>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Tobias Klauser <tklauser@distanz.ch>,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-riscv@lists.infradead.org
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On Wed, Apr 5, 2023 at 6:57=E2=80=AFAM Paul Walmsley <paul@pwsan.com> wrote=
:
>
> On Mon, 27 Mar 2023, Evan Green wrote:
>
> > We don't have enough space for these all in ELF_HWCAP{,2} and there's n=
o
> > system call that quite does this, so let's just provide an arch-specifi=
c
> > one to probe for hardware capabilities.  This currently just provides
> > m{arch,imp,vendor}id, but with the key-value pairs we can pass more in
> > the future.
> >
> > Co-developed-by: Palmer Dabbelt <palmer@rivosinc.com>
> > Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
> > Signed-off-by: Evan Green <evan@rivosinc.com>
> > Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
> > Reviewed-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
> > Tested-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
>
> Folks are already building RISC-V systems with cores that have different
> feature sets inside the same Linux system image - just like some ARM
> vendors are - so it makes sense to pass this information onto userspace.
>
> By the way, Evan, did you intend to update the copyright dates to include
> 2023?

Updated in v6.

>
> Beyond that,
>
> Reviewed-by: Paul Walmsley <paul.walmsley@sifive.com>

Thanks, Paul!
-Evan