From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756777Ab2FNX72 (ORCPT ); Thu, 14 Jun 2012 19:59:28 -0400 Received: from mail-pz0-f46.google.com ([209.85.210.46]:45611 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756727Ab2FNX7Z (ORCPT ); Thu, 14 Jun 2012 19:59:25 -0400 Message-Id: <20120614235624.973120740@linuxfoundation.org> User-Agent: quilt/0.60-20.1 Date: Thu, 14 Jun 2012 16:56:35 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Peter Korsgaard , George Pontis , Nicolas Ferre , Herbert Xu Subject: [ 12/42] hwrng: atmel-rng - fix race condition leading to repeated bits In-Reply-To: <20120614235636.GA5275@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Peter Korsgaard commit 121daad8fd1dce63076fa55aaedd5dc3f981b334 upstream. 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 Signed-off-by: Peter Korsgaard Reported-by: George Pontis Acked-by: Nicolas Ferre Signed-off-by: Herbert Xu Signed-off-by: Greg Kroah-Hartman --- drivers/char/hw_random/atmel-rng.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/drivers/char/hw_random/atmel-rng.c +++ b/drivers/char/hw_random/atmel-rng.c @@ -36,6 +36,13 @@ static int atmel_trng_read(struct hwrng /* data ready? */ if (readl(trng->base + TRNG_ODATA) & 1) { *data = readl(trng->base + TRNG_ODATA); + /* + ensure data ready is only set again AFTER the next data + word is ready in case it got set between checking ISR + and reading ODATA, so we don't risk re-reading the + same word + */ + readl(trng->base + TRNG_ISR); return 4; } else return 0; From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-Id: <20120614235624.973120740@linuxfoundation.org> Date: Thu, 14 Jun 2012 16:56:35 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Peter Korsgaard , George Pontis , Nicolas Ferre , Herbert Xu Subject: [ 12/42] hwrng: atmel-rng - fix race condition leading to repeated bits In-Reply-To: <20120614235636.GA5275@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Peter Korsgaard commit 121daad8fd1dce63076fa55aaedd5dc3f981b334 upstream. 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 Signed-off-by: Peter Korsgaard Reported-by: George Pontis Acked-by: Nicolas Ferre Signed-off-by: Herbert Xu Signed-off-by: Greg Kroah-Hartman --- drivers/char/hw_random/atmel-rng.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/drivers/char/hw_random/atmel-rng.c +++ b/drivers/char/hw_random/atmel-rng.c @@ -36,6 +36,13 @@ static int atmel_trng_read(struct hwrng /* data ready? */ if (readl(trng->base + TRNG_ODATA) & 1) { *data = readl(trng->base + TRNG_ODATA); + /* + ensure data ready is only set again AFTER the next data + word is ready in case it got set between checking ISR + and reading ODATA, so we don't risk re-reading the + same word + */ + readl(trng->base + TRNG_ISR); return 4; } else return 0;