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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Wed, 17 Oct 2018 17:37:38 +0200
Message-ID: <CAK8P3a363-ucdqEtrkUah9NPrFtQV6eH=4G3fcQtHMyMStME5w@mail.gmail.com>
Subject: Re: [PATCH V9 14/21] csky: User access
To:     Guo Ren <ren_guo@c-sky.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Daniel Lezcano <daniel.lezcano@linaro.org>,
        David Miller <davem@davemloft.net>,
        gregkh <gregkh@linuxfoundation.org>,
        Christoph Hellwig <hch@infradead.org>,
        Marc Zyngier <marc.zyngier@arm.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Rob Herring <robh@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-arch <linux-arch@vger.kernel.org>,
        DTML <devicetree@vger.kernel.org>,
        Rob Herring <robh+dt@kernel.org>, c-sky_gcc_upstream@c-sky.com
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On Tue, Oct 16, 2018 at 5:05 AM Guo Ren <ren_guo@c-sky.com> wrote:
>
> The patch adds "user access from kernel" codes.
>
> Signed-off-by: Guo Ren <ren_guo@c-sky.com>
> Cc: Arnd Bergmann <arnd@arndb.de>
> ---
>  arch/csky/include/asm/uaccess.h | 416 ++++++++++++++++++++++++++++++++++++++++
>  arch/csky/lib/usercopy.c        | 262 +++++++++++++++++++++++++
>  2 files changed, 678 insertions(+)
>  create mode 100644 arch/csky/include/asm/uaccess.h
>  create mode 100644 arch/csky/lib/usercopy.c

Reviewed-by: Arnd Bergmann <arnd@arndb.de>

The 64-bit __put_user() is usually what everyone gets wrong, but
your version seems fine. Also the access_ok() checks and
the copy_to_user() result value all look correct.

        Arnd