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Subject: Re: [PATCH v3 3/3] fdt: add support for rng-seed
To:     Hsin-Yi Wang <hsinyi@chromium.org>,
        linux-arm-kernel@lists.infradead.org
Cc:     Rob Herring <robh+dt@kernel.org>, devicetree@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>,
        Chintan Pandya <cpandya@codeaurora.org>,
        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>
References: <20190516102817.188519-1-hsinyi@chromium.org>
 <20190516102817.188519-3-hsinyi@chromium.org>
From:   Randy Dunlap <rdunlap@infradead.org>
Message-ID: <932a02f2-a1d3-a8d7-c7a4-2891024d10a2@infradead.org>
Date:   Thu, 16 May 2019 08:39:56 -0700
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On 5/16/19 3:28 AM, Hsin-Yi Wang wrote:
> Introducing a chosen node, rng-seed, which is an entropy that can be
> passed to kernel called very early to increase initial device
> randomness. Bootloader should provide this entropy and the value is
> read from /chosen/rng-seed in DT.
> 
> Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
> ---
> change v2->v3:
> 1. use arch hook for fdt pgprot change
> 2. handle CONFIG_KEXEC
> ---
>  Documentation/devicetree/bindings/chosen.txt | 14 +++++
>  drivers/of/fdt.c                             | 55 ++++++++++++++++++++
>  2 files changed, 69 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/chosen.txt b/Documentation/devicetree/bindings/chosen.txt
> index 45e79172a646..fef5c82672dc 100644
> --- a/Documentation/devicetree/bindings/chosen.txt
> +++ b/Documentation/devicetree/bindings/chosen.txt
> @@ -28,6 +28,20 @@ mode) when EFI_RNG_PROTOCOL is supported, it will be overwritten by
>  the Linux EFI stub (which will populate the property itself, using
>  EFI_RNG_PROTOCOL).
>  
> +rng-seed
> +-----------
> +
> +This property served as an entropy to add device randomness. It is parsed

                 serves


> +as a byte array, e.g.
> +
> +/ {
> +	chosen {
> +		rng-seed = <0x31 0x95 0x1b 0x3c 0xc9 0xfa 0xb3 ...>;
> +	};
> +};
> +
> +This random value should be provided by bootloader.
> +
>  stdout-path
>  -----------
>  


-- 
~Randy