Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754882Ab2HMWFM (ORCPT ); Mon, 13 Aug 2012 18:05:12 -0400 Received: from mail-gg0-f174.google.com ([209.85.161.174]:57384 "EHLO mail-gg0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754752Ab2HMWFH (ORCPT ); Mon, 13 Aug 2012 18:05:07 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg KH , torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, "Theodore Tso" Subject: [ 25/44] random: use the arch-specific rng in xfer_secondary_pool Date: Mon, 13 Aug 2012 15:02:32 -0700 Message-Id: <20120813220144.347219200@linuxfoundation.org> X-Mailer: git-send-email 1.7.10.1.362.g242cab3 In-Reply-To: <20120813220142.113186818@linuxfoundation.org> References: <20120813220142.113186818@linuxfoundation.org> User-Agent: quilt/0.60-20.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2950 Lines: 96 From: Greg KH 3.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Theodore Ts'o commit e6d4947b12e8ad947add1032dd754803c6004824 upstream. If the CPU supports a hardware random number generator, use it in xfer_secondary_pool(), where it will significantly improve things and where we can afford it. Also, remove the use of the arch-specific rng in add_timer_randomness(), since the call is significantly slower than get_cycles(), and we're much better off using it in xfer_secondary_pool() anyway. Signed-off-by: "Theodore Ts'o" Signed-off-by: Greg Kroah-Hartman --- drivers/char/random.c | 25 ++++++++++++++++--------- 1 file changed, 16 insertions(+), 9 deletions(-) --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -254,6 +254,7 @@ #include #include #include +#include #ifdef CONFIG_GENERIC_HARDIRQS # include @@ -702,11 +703,7 @@ static void add_timer_randomness(struct goto out; sample.jiffies = jiffies; - - /* Use arch random value, fall back to cycles */ - if (!arch_get_random_int(&sample.cycles)) - sample.cycles = get_cycles(); - + sample.cycles = get_cycles(); sample.num = num; mix_pool_bytes(&input_pool, &sample, sizeof(sample), NULL); @@ -838,7 +835,11 @@ static ssize_t extract_entropy(struct en */ static void xfer_secondary_pool(struct entropy_store *r, size_t nbytes) { - __u32 tmp[OUTPUT_POOL_WORDS]; + union { + __u32 tmp[OUTPUT_POOL_WORDS]; + long hwrand[4]; + } u; + int i; if (r->pull && r->entropy_count < nbytes * 8 && r->entropy_count < r->poolinfo->POOLBITS) { @@ -849,17 +850,23 @@ static void xfer_secondary_pool(struct e /* pull at least as many as BYTES as wakeup BITS */ bytes = max_t(int, bytes, random_read_wakeup_thresh / 8); /* but never more than the buffer size */ - bytes = min_t(int, bytes, sizeof(tmp)); + bytes = min_t(int, bytes, sizeof(u.tmp)); DEBUG_ENT("going to reseed %s with %d bits " "(%d of %d requested)\n", r->name, bytes * 8, nbytes * 8, r->entropy_count); - bytes = extract_entropy(r->pull, tmp, bytes, + bytes = extract_entropy(r->pull, u.tmp, bytes, random_read_wakeup_thresh / 8, rsvd); - mix_pool_bytes(r, tmp, bytes, NULL); + mix_pool_bytes(r, u.tmp, bytes, NULL); credit_entropy_bits(r, bytes*8); } + kmemcheck_mark_initialized(&u.hwrand, sizeof(u.hwrand)); + for (i = 0; i < 4; i++) + if (arch_get_random_long(&u.hwrand[i])) + break; + if (i) + mix_pool_bytes(r, &u.hwrand, sizeof(u.hwrand), 0); } /* -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/