From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5D7C6C433EF for ; Thu, 23 Jun 2022 16:54:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233485AbiFWQyJ (ORCPT ); Thu, 23 Jun 2022 12:54:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49222 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233819AbiFWQvm (ORCPT ); Thu, 23 Jun 2022 12:51:42 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9F7824BBBE; Thu, 23 Jun 2022 09:49:51 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 5520D61F90; Thu, 23 Jun 2022 16:49:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 302AFC3411B; Thu, 23 Jun 2022 16:49:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1656002990; bh=NJzA0Lyq5UTLN3pd0n/Dokq1ekEZX+EDiNe0BEQsGZE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=toLB4E3vWOY+JYmnIMq+61WUSFxy4B/+MsTA3gmabZ8glGsRcKfY0mRzFHnw6djlN GPdj/l5xNuC9MMZ074LyML8u2d4BmHliB1wVLwmharPOq0sTuEDPYx8AXK4PKH6o4g YLV0SpL3BBBonF2hNgdkVXWCHBgqfxZmAH08cPm8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dominik Brodowski , "Jason A. Donenfeld" Subject: [PATCH 4.9 094/264] random: cleanup poolinfo abstraction Date: Thu, 23 Jun 2022 18:41:27 +0200 Message-Id: <20220623164346.731825616@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220623164344.053938039@linuxfoundation.org> References: <20220623164344.053938039@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Jason A. Donenfeld" commit 91ec0fe138f107232cb36bc6112211db37cb5306 upstream. Now that we're only using one polynomial, we can cleanup its representation into constants, instead of passing around pointers dynamically to select different polynomials. This improves the codegen and makes the code a bit more straightforward. Reviewed-by: Dominik Brodowski Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman --- drivers/char/random.c | 67 ++++++++++++++++++++++---------------------------- 1 file changed, 30 insertions(+), 37 deletions(-) --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -432,14 +432,20 @@ static int random_write_wakeup_bits = 28 * polynomial which improves the resulting TGFSR polynomial to be * irreducible, which we have made here. */ -static const struct poolinfo { - int poolbitshift, poolwords, poolbytes, poolfracbits; -#define S(x) ilog2(x)+5, (x), (x)*4, (x) << (ENTROPY_SHIFT+5) - int tap1, tap2, tap3, tap4, tap5; -} poolinfo_table[] = { - /* was: x^128 + x^103 + x^76 + x^51 +x^25 + x + 1 */ +enum poolinfo { + POOL_WORDS = 128, + POOL_WORDMASK = POOL_WORDS - 1, + POOL_BYTES = POOL_WORDS * sizeof(u32), + POOL_BITS = POOL_BYTES * 8, + POOL_BITSHIFT = ilog2(POOL_WORDS) + 5, + POOL_FRACBITS = POOL_WORDS << (ENTROPY_SHIFT + 5), + /* x^128 + x^104 + x^76 + x^51 +x^25 + x + 1 */ - { S(128), 104, 76, 51, 25, 1 }, + POOL_TAP1 = 104, + POOL_TAP2 = 76, + POOL_TAP3 = 51, + POOL_TAP4 = 25, + POOL_TAP5 = 1 }; /* @@ -506,7 +512,6 @@ MODULE_PARM_DESC(ratelimit_disable, "Dis struct entropy_store; struct entropy_store { /* read-only data: */ - const struct poolinfo *poolinfo; __u32 *pool; const char *name; @@ -528,7 +533,6 @@ static void crng_reseed(struct crng_stat static __u32 input_pool_data[INPUT_POOL_WORDS] __latent_entropy; static struct entropy_store input_pool = { - .poolinfo = &poolinfo_table[0], .name = "input", .lock = __SPIN_LOCK_UNLOCKED(input_pool.lock), .pool = input_pool_data @@ -551,33 +555,26 @@ static __u32 const twist_table[8] = { static void _mix_pool_bytes(struct entropy_store *r, const void *in, int nbytes) { - unsigned long i, tap1, tap2, tap3, tap4, tap5; + unsigned long i; int input_rotate; - int wordmask = r->poolinfo->poolwords - 1; const unsigned char *bytes = in; __u32 w; - tap1 = r->poolinfo->tap1; - tap2 = r->poolinfo->tap2; - tap3 = r->poolinfo->tap3; - tap4 = r->poolinfo->tap4; - tap5 = r->poolinfo->tap5; - input_rotate = r->input_rotate; i = r->add_ptr; /* mix one byte at a time to simplify size handling and churn faster */ while (nbytes--) { w = rol32(*bytes++, input_rotate); - i = (i - 1) & wordmask; + i = (i - 1) & POOL_WORDMASK; /* XOR in the various taps */ w ^= r->pool[i]; - w ^= r->pool[(i + tap1) & wordmask]; - w ^= r->pool[(i + tap2) & wordmask]; - w ^= r->pool[(i + tap3) & wordmask]; - w ^= r->pool[(i + tap4) & wordmask]; - w ^= r->pool[(i + tap5) & wordmask]; + w ^= r->pool[(i + POOL_TAP1) & POOL_WORDMASK]; + w ^= r->pool[(i + POOL_TAP2) & POOL_WORDMASK]; + w ^= r->pool[(i + POOL_TAP3) & POOL_WORDMASK]; + w ^= r->pool[(i + POOL_TAP4) & POOL_WORDMASK]; + w ^= r->pool[(i + POOL_TAP5) & POOL_WORDMASK]; /* Mix the result back in with a twist */ r->pool[i] = (w >> 3) ^ twist_table[w & 7]; @@ -675,7 +672,6 @@ static void process_random_ready_list(vo static void credit_entropy_bits(struct entropy_store *r, int nbits) { int entropy_count, orig; - const int pool_size = r->poolinfo->poolfracbits; int nfrac = nbits << ENTROPY_SHIFT; if (!nbits) @@ -709,25 +705,25 @@ retry: * turns no matter how large nbits is. */ int pnfrac = nfrac; - const int s = r->poolinfo->poolbitshift + ENTROPY_SHIFT + 2; + const int s = POOL_BITSHIFT + ENTROPY_SHIFT + 2; /* The +2 corresponds to the /4 in the denominator */ do { - unsigned int anfrac = min(pnfrac, pool_size/2); + unsigned int anfrac = min(pnfrac, POOL_FRACBITS/2); unsigned int add = - ((pool_size - entropy_count)*anfrac*3) >> s; + ((POOL_FRACBITS - entropy_count)*anfrac*3) >> s; entropy_count += add; pnfrac -= anfrac; - } while (unlikely(entropy_count < pool_size-2 && pnfrac)); + } while (unlikely(entropy_count < POOL_FRACBITS-2 && pnfrac)); } if (WARN_ON(entropy_count < 0)) { pr_warn("negative entropy/overflow: pool %s count %d\n", r->name, entropy_count); entropy_count = 0; - } else if (entropy_count > pool_size) - entropy_count = pool_size; + } else if (entropy_count > POOL_FRACBITS) + entropy_count = POOL_FRACBITS; if (cmpxchg(&r->entropy_count, orig, entropy_count) != orig) goto retry; @@ -744,13 +740,11 @@ retry: static int credit_entropy_bits_safe(struct entropy_store *r, int nbits) { - const int nbits_max = r->poolinfo->poolwords * 32; - if (nbits < 0) return -EINVAL; /* Cap the value to avoid overflows */ - nbits = min(nbits, nbits_max); + nbits = min(nbits, POOL_BITS); credit_entropy_bits(r, nbits); return 0; @@ -1394,7 +1388,7 @@ static size_t account(struct entropy_sto int entropy_count, orig, have_bytes; size_t ibytes, nfrac; - BUG_ON(r->entropy_count > r->poolinfo->poolfracbits); + BUG_ON(r->entropy_count > POOL_FRACBITS); /* Can we pull enough? */ retry: @@ -1460,8 +1454,7 @@ static void extract_buf(struct entropy_s /* Generate a hash across the pool */ spin_lock_irqsave(&r->lock, flags); - blake2s_update(&state, (const u8 *)r->pool, - r->poolinfo->poolwords * sizeof(*r->pool)); + blake2s_update(&state, (const u8 *)r->pool, POOL_BYTES); blake2s_final(&state, hash); /* final zeros out state */ /* @@ -1756,7 +1749,7 @@ static void __init init_std_data(struct unsigned long rv; mix_pool_bytes(r, &now, sizeof(now)); - for (i = r->poolinfo->poolbytes; i > 0; i -= sizeof(rv)) { + for (i = POOL_BYTES; i > 0; i -= sizeof(rv)) { if (!arch_get_random_seed_long(&rv) && !arch_get_random_long(&rv)) rv = random_get_entropy();