kernel/linux
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ synced 2026-11-10 20:48:12 +00:00
Code Issues Releases Packages Activity

hwrng: airoha - set rng quality to 900

Browse source 
[ Upstream commit c0008a29a0 ]

Airoha uses RAW mode to collect noise from the TRNG. These appear to
be unprocessed oscillations from the tero loop. For this reason, they
do not have a perfect distribution and entropy. Simple noise compression
reduces its size by 9%, so setting the quality to 900 seems reasonable.
The same value is used by the downstream driver.

Compare the size before and after compression:
$ ls -l random_airoha*
-rw-r--r-- 1 aleksander aleksander 76546048 Jan  3 23:43 random_airoha
-rw-rw-r-- 1 aleksander aleksander 69783562 Jan  5 20:23 random_airoha.zip

FIPS test results:
$ cat random_airoha | rngtest -c 10000
rngtest 2.6
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: 200000032
rngtest: FIPS 140-2 successes: 0
rngtest: FIPS 140-2 failures: 10000
rngtest: FIPS 140-2(2001-10-10) Monobit: 9957
rngtest: FIPS 140-2(2001-10-10) Poker: 10000
rngtest: FIPS 140-2(2001-10-10) Runs: 10000
rngtest: FIPS 140-2(2001-10-10) Long run: 4249
rngtest: FIPS 140-2(2001-10-10) Continuous run: 0
rngtest: input channel speed: (min=953.674; avg=27698.935; max=19073.486)Mibits/s
rngtest: FIPS tests speed: (min=59.791; avg=298.028; max=328.853)Mibits/s
rngtest: Program run time: 647638 microseconds

In general, these data look like real noise, but with lower entropy
than expected.

Fixes: e53ca8efcc ("hwrng: airoha - add support for Airoha EN7581 TRNG")
Suggested-by: Benjamin Larsson <benjamin.larsson@genexis.eu>
Signed-off-by: Aleksander Jan Bajkowski <olek2@wp.pl>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Aleksander Jan Bajkowski 2026-01-05 21:41:49 +01:00 • committed by Greg Kroah-Hartman
commit 6abdd33a08
1 changed files with 1 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files