Re: [PATCH v3 0/4] Raspberry Pi 4 HWRNG Support

Stefan Wahren
2019-11-21T10:14:54Z

Hi,

Am 20.11.19 um 20:50 schrieb Nicolas Saenz Julienne:
> On Wed, 2019-11-20 at 17:16 +0100, Stefan Wahren wrote:
>> Hi Stephen,
>>
>> Am 20.11.19 um 04:16 schrieb Stephen Brennan:
>>> This patch series enables support for the HWRNG included on the Raspberry
>>> Pi 4. It is simply a rebase of Stefan's branch [1]. I went ahead and
>>> tested this out on a Pi 4. Prior to this patch series, attempting to use
>>> the hwrng gives:
>>>
>>> $ head -c 2 /dev/hwrng
>>> head: /dev/hwrng: Input/output error
>>>
>>> After this series, the same command gives two random bytes.
>> just a note: a more expressive test would be running rngtest (package
>> rng-tools) on this device.
> Just had a go at it,
>
> root@rpi4:~# rngtest -c 1000 < /dev/hwrng
> rngtest 2-unofficial-mt.14
> Copyright (c) 2004 by Henrique de Moraes Holschuh
> This is free software; see the source for copying conditions. There is NO
> warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
>
> rngtest: starting FIPS tests...
> rngtest: bits received from input: 20000032
> rngtest: FIPS 140-2 successes: 998
> rngtest: FIPS 140-2 failures: 2
> rngtest: FIPS 140-2(2001-10-10) Monobit: 0
> rngtest: FIPS 140-2(2001-10-10) Poker: 1
> rngtest: FIPS 140-2(2001-10-10) Runs: 0
> rngtest: FIPS 140-2(2001-10-10) Long run: 1
> rngtest: FIPS 140-2(2001-10-10) Continuous run: 0
> rngtest: input channel speed: (min=1.284; avg=113.786; max=126.213)Kibits/s
> rngtest: FIPS tests speed: (min=17.122; avg=28.268; max=28.812)Mibits/s
> rngtest: Program run time: 172323761 microseconds
>
> AFAIR (Arch wiki) some small failures are acceptable.
>
> Regards,
> Nicolas
>
thanks for the results. AFAIR the downstream implementation [1] has a
significant higher input speed. So there is possibly some room for
optimizations later.

Regards
Stefan

[1] -