From:   =?utf-8?B?QmrDtnJuIFTDtnBlbA==?= <bjorn@kernel.org>
To:     Alexandre Ghiti <alexghiti@rivosinc.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        Alexander Potapenko <glider@google.com>,
        Andrey Konovalov <andreyknvl@gmail.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Ard Biesheuvel <ardb@kernel.org>,
        Conor Dooley <conor@kernel.org>,
        linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
        kasan-dev@googlegroups.com, linux-efi@vger.kernel.org
Cc:     Alexandre Ghiti <alexghiti@rivosinc.com>
Subject: Re: [PATCH v4 3/6] riscv: Move DTB_EARLY_BASE_VA to the kernel
 address space
In-Reply-To: <20230203075232.274282-4-alexghiti@rivosinc.com>
References: <20230203075232.274282-1-alexghiti@rivosinc.com>
 <20230203075232.274282-4-alexghiti@rivosinc.com>
Date:   Fri, 17 Feb 2023 15:58:48 +0100
Message-ID: <873574uymv.fsf@all.your.base.are.belong.to.us>
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Alexandre Ghiti <alexghiti@rivosinc.com> writes:

> The early virtual address should lie in the kernel address space for
> inline kasan instrumentation to succeed, otherwise kasan tries to
> dereference an address that does not exist in the address space (since
> kasan only maps *kernel* address space, not the userspace).
>
> Simply use the very first address of the kernel address space for the
> early fdt mapping.
>
> It allowed an Ubuntu kernel to boot successfully with inline
> instrumentation.
>
> Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>

Reviewed-by: Bj=C3=B6rn T=C3=B6pel <bjorn@rivosinc.com>