From: Keith Packard <keithp@keithp.com>
To: Matt Mackall <mpm@selenic.com>, Herbert Xu <herbert@gondor.apana.org.au>
Cc: linux-kernel@vger.kernel.org, Keith Packard <keithp@keithp.com>
Subject: [PATCH] hwrng: core - allow perfect entropy from hardware devices
Date: Tue, 17 Mar 2015 22:13:28 -0700 [thread overview]
Message-ID: <1426655608-24749-1-git-send-email-keithp@keithp.com> (raw)
Hardware random number quality is measured from 0 (no entropy) to 1024
(perfect entropy). Allow hardware devices to assert the full range by
truncating the device-provided value at 1024 instead of 1023.
Signed-off-by: Keith Packard <keithp@keithp.com>
---
drivers/char/hw_random/core.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index 1500cfd..b726683 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -98,7 +98,8 @@ static inline int hwrng_init(struct hwrng *rng)
add_early_randomness(rng);
current_quality = rng->quality ? : default_quality;
- current_quality &= 1023;
+ if (current_quality > 1024)
+ current_quality = 1024;
if (current_quality == 0 && hwrng_fill)
kthread_stop(hwrng_fill);
--
2.1.4
next reply other threads:[~2015-03-18 5:21 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-18 5:13 Keith Packard [this message]
2015-03-18 5:18 ` Herbert Xu
2015-03-18 7:15 ` Keith Packard
2015-03-18 8:58 ` Herbert Xu
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