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| author | Peter Korsgaard | 2012-05-31 12:53:08 +0200 |
|---|---|---|
| committer | Herbert Xu | 2012-05-31 12:53:08 +0200 |
| commit | 121daad8fd1dce63076fa55aaedd5dc3f981b334 (patch) | |
| tree | b8dffca034cb3763706ac7bf4aeac94a29661749 /arch/x86 | |
| parent | crypto: aesni-intel - move more common code to ablk_init_common (diff) | |
| download | kernel-qcow2-linux-121daad8fd1dce63076fa55aaedd5dc3f981b334.tar.gz kernel-qcow2-linux-121daad8fd1dce63076fa55aaedd5dc3f981b334.tar.xz kernel-qcow2-linux-121daad8fd1dce63076fa55aaedd5dc3f981b334.zip | |
hwrng: atmel-rng - fix race condition leading to repeated bits
Data valid gets cleared by reading the ISR (status register) and NOT from
reading ODATA (data register). A new data word can become available between
checking ISR and reading ODATA, causing us to reuse the same data word next
time atmel_trng_read() gets called, if that happens before the following
data word is ready.
With this fixed, rngtest no longer complains of 'Continous run' errors.
Before:
rngtest -c 1000 < /dev/hwrng
rngtest 3
Copyright (c) 2004 by Henrique de Moraes Holschuh
This is free software; see the source for copying conditions. There is NO warr.
rngtest: starting FIPS tests...
rngtest: bits received from input: 20000032
rngtest: FIPS 140-2 successes: 923
rngtest: FIPS 140-2 failures: 77
rngtest: FIPS 140-2(2001-10-10) Monobit: 0
rngtest: FIPS 140-2(2001-10-10) Poker: 0
rngtest: FIPS 140-2(2001-10-10) Runs: 1
rngtest: FIPS 140-2(2001-10-10) Long run: 0
rngtest: FIPS 140-2(2001-10-10) Continuous run: 76
rngtest: input channel speed: (min=721.402; avg=46003.510; max=49321.338)Kibitss
rngtest: FIPS tests speed: (min=11.442; avg=12.714; max=12.801)Mibits/s
rngtest: Program run time: 1931860 microseconds
After:
rngtest -c 1000 < /dev/hwrng
rngtest 3
Copyright (c) 2004 by Henrique de Moraes Holschuh
This is free software; see the source for copying conditions. There is NO warr.
rngtest: starting FIPS tests...
rngtest: bits received from input: 20000032
rngtest: FIPS 140-2 successes: 1000
rngtest: FIPS 140-2 failures: 0
rngtest: FIPS 140-2(2001-10-10) Monobit: 0
rngtest: FIPS 140-2(2001-10-10) Poker: 0
rngtest: FIPS 140-2(2001-10-10) Runs: 0
rngtest: FIPS 140-2(2001-10-10) Long run: 0
rngtest: FIPS 140-2(2001-10-10) Continuous run: 0
rngtest: input channel speed: (min=777.518; avg=36988.482; max=43115.342)Kibitss
rngtest: FIPS tests speed: (min=11.951; avg=12.715; max=12.887)Mibits/s
rngtest: Program run time: 2035543 microseconds
Cc: stable@vger.kernel.org
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Reported-by: George Pontis <GPontis@z9.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'arch/x86')
0 files changed, 0 insertions, 0 deletions