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From: Mike Rapoport <rppt@linux.ibm.com>
To: Hsin-Yi Wang <hsinyi@chromium.org>
Cc: linux-arm-kernel@lists.infradead.org,
	Rob Herring <robh+dt@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Frank Rowand <frowand.list@gmail.com>,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	Stephen Boyd <swboyd@chromium.org>,
	Kees Cook <keescook@chromium.org>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	boot-architecture@lists.linaro.org,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Michal Hocko <mhocko@suse.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>
Subject: Re: [PATCH v2 1/2] fdt: add support for rng-seed
Date: Mon, 13 May 2019 11:42:02 +0300	[thread overview]
Message-ID: <20190513084201.GA9271@rapoport-lnx> (raw)
In-Reply-To: <20190513003819.356-1-hsinyi@chromium.org>

On Mon, May 13, 2019 at 08:38:18AM +0800, 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 log:
> v1->v2:
> * call function in early_init_dt_scan_chosen
> * will add doc to devicetree-org/dt-schema on github if this is accepted
> ---
>  Documentation/devicetree/bindings/chosen.txt | 14 ++++++++++++++
>  drivers/of/fdt.c                             | 11 +++++++++++
>  2 files changed, 25 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
> +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
>  -----------
>  
> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
> index de893c9616a1..96ea5eba9dd5 100644
> --- a/drivers/of/fdt.c
> +++ b/drivers/of/fdt.c
> @@ -24,6 +24,7 @@
>  #include <linux/debugfs.h>
>  #include <linux/serial_core.h>
>  #include <linux/sysfs.h>
> +#include <linux/random.h>
>  
>  #include <asm/setup.h>  /* for COMMAND_LINE_SIZE */
>  #include <asm/page.h>
> @@ -1079,6 +1080,7 @@ int __init early_init_dt_scan_chosen(unsigned long node, const char *uname,
>  {
>  	int l;
>  	const char *p;
> +	const void *rng_seed;
>  
>  	pr_debug("search \"chosen\", depth: %d, uname: %s\n", depth, uname);
>  
> @@ -1113,6 +1115,15 @@ int __init early_init_dt_scan_chosen(unsigned long node, const char *uname,
>  
>  	pr_debug("Command line is: %s\n", (char*)data);
>  
> +	rng_seed = of_get_flat_dt_prop(node, "rng-seed", &l);
> +	if (!rng_seed || l == 0)
> +		return 1;
> +
> +	/* try to clear seed so it won't be found. */
> +        fdt_nop_property(initial_boot_params, node, "rng-seed");
> +
> +        add_device_randomness(rng_seed, l);

Please fix the indentation. 

> +
>  	/* break now */
>  	return 1;
>  }
> -- 
> 2.20.1
> 

-- 
Sincerely yours,
Mike.


  parent reply	other threads:[~2019-05-13  8:42 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-13  0:38 Hsin-Yi Wang
2019-05-13  0:38 ` [PATCH v2 2/2] amr64: map FDT as RW for early_init_dt_scan() Hsin-Yi Wang
2019-05-13  8:58   ` Mike Rapoport
2019-05-13 11:14     ` Hsin-Yi Wang
2019-05-14 15:42       ` Mike Rapoport
2019-05-15 10:24         ` Hsin-Yi Wang
2019-05-15 20:11           ` Ard Biesheuvel
2019-05-16 11:07             ` Mike Rapoport
2019-05-14 21:05       ` Stephen Boyd
2019-05-15  5:00         ` Mike Rapoport
2019-05-15 10:34           ` Hsin-Yi Wang
2019-05-13  8:42 ` Mike Rapoport [this message]
2019-05-13 13:14 ` [PATCH v2 1/2] fdt: add support for rng-seed Rob Herring
2019-05-15  9:07   ` Hsin-Yi Wang

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