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From:   Rob Herring <robh+dt@kernel.org>
Date:   Mon, 17 Apr 2023 08:31:24 -0500
Message-ID: <CAL_JsqL1L4EOpVm7nXbZ0t8-9wHVq4531MN4Csemi-4SBd=zig@mail.gmail.com>
Subject: Re: [PATCH v3 1/1] of: fdt: Scan /memreserve/ last
To:     Lucas Tanure <tanure@linux.com>,
        Michael Ellerman <mpe@ellerman.id.au>,
        linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Cc:     Frank Rowand <frowand.list@gmail.com>,
        Mike Rapoport <rppt@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, jbrunet@baylibre.com,
        linux-amlogic@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org,
        martin.blumenstingl@googlemail.com, narmstrong@baylibre.com,
        stefan@agner.ch
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On Wed, Apr 12, 2023 at 5:46=E2=80=AFPM Lucas Tanure <tanure@linux.com> wro=
te:
>
> Change the order of scanning /memreserve/ and /reserved-memory node.
> /reserved-memory node should go first, as it has a more updated
> description of the memory regions and it can apply flags, like nomap.
> Also, /memreserve/ should avoid reserving regions described in
> /reserved-memory node.

Please give some background details why we need to make this change.
As-is, sounds like some theoretical issue. IOW, incorporate some of
the details in the cover letter here. For single patches, you don't
need a cover letter anyways.

Powerpc folks, please comment and/or test. I worry there could be some
subtle differences with this change.

>
> Signed-off-by: Lucas Tanure <tanure@linux.com>
> ---
>  drivers/of/fdt.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
> index d1a68b6d03b3..c28aedd7ae1f 100644
> --- a/drivers/of/fdt.c
> +++ b/drivers/of/fdt.c
> @@ -635,6 +635,9 @@ void __init early_init_fdt_scan_reserved_mem(void)
>         if (!initial_boot_params)
>                 return;
>
> +       fdt_scan_reserved_mem();
> +       fdt_reserve_elfcorehdr();
> +
>         /* Process header /memreserve/ fields */
>         for (n =3D 0; ; n++) {
>                 fdt_get_mem_rsv(initial_boot_params, n, &base, &size);
> @@ -643,8 +646,6 @@ void __init early_init_fdt_scan_reserved_mem(void)
>                 memblock_reserve(base, size);
>         }
>
> -       fdt_scan_reserved_mem();
> -       fdt_reserve_elfcorehdr();
>         fdt_init_reserved_mem();
>  }
>
> --
> 2.40.0
>