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From:   Ard Biesheuvel <ardb@kernel.org>
Date:   Mon, 13 Jun 2022 11:42:44 +0200
Message-ID: <CAMj1kXFn_FKt2jLJOntvT0FBtL9b=VWZdrBFpn48LBMDLy1WBQ@mail.gmail.com>
Subject: Re: [PATCH v4 5/6] mm: Only remove nomap flag for initrd
To:     Wupeng Ma <mawupeng1@huawei.com>, Will Deacon <will@kernel.org>,
        Catalin Marinas <catalin.marinas@arm.com>
Cc:     Jonathan Corbet <corbet@lwn.net>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        X86 ML <x86@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
        Darren Hart <dvhart@infradead.org>,
        Andy Shevchenko <andy@infradead.org>,
        Mike Rapoport <rppt@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
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On Mon, 13 Jun 2022 at 10:00, Wupeng Ma <mawupeng1@huawei.com> wrote:
>
> From: Ma Wupeng <mawupeng1@huawei.com>
>
> Commit 177e15f0c144 ("arm64: add the initrd region to the linear mapping explicitly")
> remove all the flags of the memory used by initrd. This is fine since
> MEMBLOCK_MIRROR is not used in arm64.
>
> However with mirrored feature introduced to arm64, this will clear the mirrored
> flag used by initrd, which will lead to error log printed by
> find_zone_movable_pfns_for_nodes() if the lower 4G range has some non-mirrored
> memory.
>
> To solve this problem, only MEMBLOCK_NOMAP flag will be removed via
> memblock_clear_nomap().
>
> Signed-off-by: Ma Wupeng <mawupeng1@huawei.com>

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>

This needs and ack from the arm64 maintainers, please?
And also please fix the subject to include 'arm64'


> ---
>  arch/arm64/mm/init.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> index 339ee84e5a61..8456dbae9441 100644
> --- a/arch/arm64/mm/init.c
> +++ b/arch/arm64/mm/init.c
> @@ -350,8 +350,8 @@ void __init arm64_memblock_init(void)
>                         "initrd not fully accessible via the linear mapping -- please check your bootloader ...\n")) {
>                         phys_initrd_size = 0;
>                 } else {
> -                       memblock_remove(base, size); /* clear MEMBLOCK_ flags */
>                         memblock_add(base, size);
> +                       memblock_clear_nomap(base, size);
>                         memblock_reserve(base, size);
>                 }
>         }
> --
> 2.25.1
>