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From:   Rob Herring <robh+dt@kernel.org>
Date:   Thu, 16 May 2019 10:32:37 -0500
Message-ID: <CAL_Jsq+dVg9E_EzpoC4Bz1ytUckDGXUcEJyU5pV2HS6rZuKmHA@mail.gmail.com>
Subject: Re: [PATCH v3 2/3] arm64: implement update_fdt_pgprot()
To:     Hsin-Yi Wang <hsinyi@chromium.org>
Cc:     "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" 
        <linux-arm-kernel@lists.infradead.org>, devicetree@vger.kernel.org,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Frank Rowand <frowand.list@gmail.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Mike Rapoport <rppt@linux.ibm.com>,
        Ard Biesheuvel <ard.biesheuvel@linaro.org>,
        Miles Chen <miles.chen@mediatek.com>,
        James Morse <james.morse@arm.com>,
        Andrew Murray <andrew.murray@arm.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Jun Yao <yaojun8558363@gmail.com>, Yu Zhao <yuzhao@google.com>,
        Robin Murphy <robin.murphy@arm.com>,
        Laura Abbott <labbott@redhat.com>,
        Stephen Boyd <swboyd@chromium.org>,
        Kees Cook <keescook@chromium.org>
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On Thu, May 16, 2019 at 9:51 AM Hsin-Yi Wang <hsinyi@chromium.org> wrote:
>
> On Thu, May 16, 2019 at 10:37 PM Rob Herring <robh+dt@kernel.org> wrote:
>
> >
> > Why not just map the FDT R/W at the start and change it to RO just
> > before calling unflatten_device_tree? Then all the FDT scanning
> > functions or any future fixups we need can just assume R/W. That is
> > essentially what Stephen suggested. However, there's no need for a
> > weak function as it can all be done within the arch code.
> >
> We need to add a new seed for kexec

Doesn't kexec operate on a copy because it already does modifications.

Rob