hwrng: core - allow perfect entropy from hardware devices

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>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index 83161dde53ee..571ef61f8ea9 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -179,7 +179,8 @@ skip_init:
         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);