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From:   =?utf-8?B?QmrDtnJuIFTDtnBlbA==?= <bjorn@kernel.org>
To:     Alexandre Ghiti <alexghiti@rivosinc.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org
Cc:     Alexandre Ghiti <alexghiti@rivosinc.com>
Subject: Re: [PATCH v2] riscv: Allow to downgrade paging mode from the
 command line
In-Reply-To: <20221215081948.1256610-1-alexghiti@rivosinc.com>
References: <20221215081948.1256610-1-alexghiti@rivosinc.com>
Date:   Thu, 15 Dec 2022 12:30:46 +0100
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Alexandre Ghiti <alexghiti@rivosinc.com> writes:

> Add 2 early command line parameters called "no5lvl" and "no4lvl" (using
> the same naming as x86) to allow a user to downgrade from sv57 (the
> default mode if the hardware supports it) to sv48 or sv39.
>
> Note that going through the device tree to get the kernel command line
> works with ACPI too since the efi stub creates a device tree anyway with
> the command line.
>
> Also, as those params are treated very early in the boot process and we
> use standard device tree functions that may be kasan instrumented, we
> only enable them for !KASAN configurations.
>
> Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>

Reviewed-by: Bj=C3=B6rn T=C3=B6pel <bjorn@kernel.org>