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References: <20210415110426.2238-1-alex@ghiti.fr>
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From:   Anup Patel <anup@brainfault.org>
Date:   Fri, 16 Apr 2021 16:11:50 +0530
Message-ID: <CAAhSdy2pD2q99-g3QSSHbpqw1ZD402fStFmbKNFzht2m=MS8mQ@mail.gmail.com>
Subject: Re: [PATCH] riscv: Protect kernel linear mapping only if
 CONFIG_STRICT_KERNEL_RWX is set
To:     Alexandre Ghiti <alex@ghiti.fr>
Cc:     Jonathan Corbet <corbet@lwn.net>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Arnd Bergmann <arnd@arndb.de>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Alexander Potapenko <glider@google.com>,
        Dmitry Vyukov <dvyukov@google.com>, linux-doc@vger.kernel.org,
        linux-riscv <linux-riscv@lists.infradead.org>,
        "linux-kernel@vger.kernel.org List" <linux-kernel@vger.kernel.org>,
        kasan-dev@googlegroups.com,
        linux-arch <linux-arch@vger.kernel.org>,
        Linux Memory Management List <linux-mm@kvack.org>
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On Thu, Apr 15, 2021 at 4:34 PM Alexandre Ghiti <alex@ghiti.fr> wrote:
>
> If CONFIG_STRICT_KERNEL_RWX is not set, we cannot set different permissions
> to the kernel data and text sections, so make sure it is defined before
> trying to protect the kernel linear mapping.
>
> Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>

Maybe you should add "Fixes:" tag in commit tag ?

Otherwise it looks good.

Reviewed-by: Anup Patel <anup@brainfault.org>

Regards,
Anup

> ---
>  arch/riscv/kernel/setup.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
> index 626003bb5fca..ab394d173cd4 100644
> --- a/arch/riscv/kernel/setup.c
> +++ b/arch/riscv/kernel/setup.c
> @@ -264,12 +264,12 @@ void __init setup_arch(char **cmdline_p)
>
>         sbi_init();
>
> -       if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX))
> +       if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)) {
>                 protect_kernel_text_data();
> -
> -#if defined(CONFIG_64BIT) && defined(CONFIG_MMU)
> -       protect_kernel_linear_mapping_text_rodata();
> +#ifdef CONFIG_64BIT
> +               protect_kernel_linear_mapping_text_rodata();
>  #endif
> +       }
>
>  #ifdef CONFIG_SWIOTLB
>         swiotlb_init(1);
> --
> 2.20.1
>