2019-02-13 15:24:14

by Philipp Puschmann

Subject: [PATCH] crypto: caam: set hwrng quality level

When quality is set to 0 this driver is not used as randomness source by
HWRNG framework at all. So set the quality and finally make this driver
work. The value of the quality was discussed before
( see https://patchwork.kernel.org/patch/9850669/ ) and it is still a rough
value.

Signed-off-by: Philipp Puschmann <[email protected]>
---
drivers/crypto/caam/caamrng.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/crypto/caam/caamrng.c b/drivers/crypto/caam/caamrng.c
index a387c8d49a62..b6fd60f7638e 100644
--- a/drivers/crypto/caam/caamrng.c
+++ b/drivers/crypto/caam/caamrng.c
@@ -294,6 +294,7 @@ static struct hwrng caam_rng = {
.name = "rng-caam",
.cleanup = caam_cleanup,
.read = caam_read,
+ .quality = 990,
};

static void __exit caam_rng_exit(void)
--
2.20.1

2019-02-19 06:57:50

by Horia Geanta

Subject: Re: [PATCH] crypto: caam: set hwrng quality level

On 2/13/2019 4:49 PM, Philipp Puschmann wrote:
> When quality is set to 0 this driver is not used as randomness source by
> HWRNG framework at all. So set the quality and finally make this driver
> work. The value of the quality was discussed before
> ( see see https://patchwork.kernel.org/patch/9850669/ ) and it is still a rough
> value.
>
In the same thread you mention, the conclusion is that caamrng should be
properly configured (TRNG instead of DRBG) before claiming to be a reliable
hwrng entropy source.

Horia