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From: Mark Rutland <mark.rutland@arm.com>
To: Mark Brown <broonie@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	Richard Henderson <richard.henderson@linaro.org>,
	Will Deacon <will@kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>
Subject: Re: [PATCH v10 3/3] arm64: Use v8.5-RNG entropy for KASLR seed
Date: Fri, 10 Jan 2020 12:35:36 +0000	[thread overview]
Message-ID: <20200110123536.GC31707@lakrids.cambridge.arm.com> (raw)
In-Reply-To: <20200110122341.8445-4-broonie@kernel.org>

On Fri, Jan 10, 2020 at 12:23:41PM +0000, Mark Brown wrote:
> When seeding KALSR on a system where we have architecture level random
> number generation make use of that entropy, mixing it in with the seed
> passed by the bootloader. Since this is run very early in init before
> feature detection is complete we open code rather than use archrandom.h.
> 
> Signed-off-by: Mark Brown <broonie@kernel.org>

Reviewed-by: Mark Rutland <mark.rutland@arm.com>

Mark.

> ---
>  arch/arm64/kernel/kaslr.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/arch/arm64/kernel/kaslr.c b/arch/arm64/kernel/kaslr.c
> index 2a11a962e571..53b8a4ee64ff 100644
> --- a/arch/arm64/kernel/kaslr.c
> +++ b/arch/arm64/kernel/kaslr.c
> @@ -120,6 +120,17 @@ u64 __init kaslr_early_init(u64 dt_phys)
>  		return 0;
>  	}
>  
> +	/*
> +	 * Mix in any entropy obtainable architecturally, open coded
> +	 * since this runs extremely early.
> +	 */
> +	if (__early_cpu_has_rndr()) {
> +		unsigned long raw;
> +
> +		if (__arm64_rndr(&raw))
> +			seed ^= raw;
> +	}
> +
>  	if (!seed) {
>  		kaslr_status = KASLR_DISABLED_NO_SEED;
>  		return 0;
> -- 
> 2.20.1
> 

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  reply	other threads:[~2020-01-10 12:35 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-10 12:23 [PATCH v10 0/3] ARMv8.5-RNG support Mark Brown
2020-01-10 12:23 ` [PATCH v10 1/3] arm64: Implement archrandom.h for ARMv8.5-RNG Mark Brown
2020-01-14 17:44   ` Will Deacon
2020-01-15  7:40     ` Ard Biesheuvel
2020-01-15  9:16       ` Will Deacon
2020-01-15  9:24         ` Ard Biesheuvel
2020-01-15 11:07           ` Mark Brown
2020-01-15 11:16             ` Will Deacon
2020-01-15 14:26             ` Catalin Marinas
2020-01-16  0:23               ` Richard Henderson
2020-01-16 11:02                 ` Catalin Marinas
2020-01-16 11:10                   ` Ard Biesheuvel
2020-01-16 11:40                     ` Catalin Marinas
2020-01-10 12:23 ` [PATCH v10 2/3] arm64: random: Add data to pool from setup_arch() Mark Brown
2020-01-10 12:35   ` Mark Rutland
2020-01-13 19:09   ` Richard Henderson
2020-01-15  7:48   ` Ard Biesheuvel
2020-01-15  9:16     ` Will Deacon
2020-01-15  9:22       ` Ard Biesheuvel
2020-01-15 10:11         ` Mark Rutland
2020-01-15 14:01           ` Mark Brown
2020-01-15 12:07       ` Mark Brown
2020-01-15 12:42         ` Will Deacon
2020-01-15 13:36           ` Ard Biesheuvel
2020-01-15 17:04             ` Mark Brown
2020-01-16 11:33               ` Will Deacon
2020-01-15 15:40           ` Mark Brown
2020-01-10 12:23 ` [PATCH v10 3/3] arm64: Use v8.5-RNG entropy for KASLR seed Mark Brown
2020-01-10 12:35   ` Mark Rutland [this message]
2020-01-13 19:09   ` Richard Henderson

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