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 3EE67C4332F for ; Tue, 19 Apr 2022 11:34:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344814AbiDSLgz (ORCPT ); Tue, 19 Apr 2022 07:36:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38736 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235055AbiDSLgy (ORCPT ); Tue, 19 Apr 2022 07:36:54 -0400 Received: from sipsolutions.net (s3.sipsolutions.net [IPv6:2a01:4f8:191:4433::2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2FCD02E9C9; Tue, 19 Apr 2022 04:34:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sipsolutions.net; s=mail; h=Content-Transfer-Encoding:MIME-Version: Content-Type:References:In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-To: Resent-Cc:Resent-Message-ID; bh=PBEaZlFaHYvw3+tY3UhjQeVca+KaL0Du1BTdeZIcC7U=; t=1650368051; x=1651577651; b=sfd1r0tjdRraJErLzIANMDeOfosZEMb0ui5naTY2Sv8s1iq ZQioNRVtMzu7mArCV2oZOA5f4Kc4lvB62uJmdDSVceTw1XyW8DJnGSgv2dT+tzHR+6nly5Fb+RQH0 /K1/CWN5jCuIGac6qOaw8rWSnslEkeS9CMwbSgLfzdgmjgSZwwBsdmeFEIHW3it8vLR5yNchX36PJ RaqoFLdtI6GL9kKDGCa/IyvPG6z5wQ2yOZH3Tg3gg6b7NS0QzW5f6PCqdziEWNHBS0pzC9ce65O0U KkE6kQYQ9mnhWQaLoVgiPWDi1rbO4NT9B4YGlILW31ICGdTVvqwpVKP+ak4aLhwg==; Received: by sipsolutions.net with esmtpsa (TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.95) (envelope-from ) id 1ngm6l-00BueY-OI; Tue, 19 Apr 2022 13:33:23 +0200 Message-ID: <694c2318d98973ee8995e891f81216ad267341dc.camel@sipsolutions.net> Subject: Re: [PATCH v5 08/11] um: use fallback for random_get_entropy() instead of zero From: Johannes Berg To: "Jason A. Donenfeld" , linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org, tglx@linutronix.de, arnd@arndb.de Cc: Theodore Ts'o , Dominik Brodowski , Russell King , Catalin Marinas , Will Deacon , Geert Uytterhoeven , Thomas Bogendoerfer , Paul Walmsley , Palmer Dabbelt , Albert Ou , "David S . Miller" , Richard Weinberger , Anton Ivanov , Ingo Molnar , Borislav Petkov , Dave Hansen , "H . Peter Anvin" , Chris Zankel , Max Filippov , Stephen Boyd , Dinh Nguyen , linux-arm-kernel@lists.infradead.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-riscv@lists.infradead.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org, x86@kernel.org, linux-xtensa@linux-xtensa.org Date: Tue, 19 Apr 2022 13:33:21 +0200 In-Reply-To: <20220419111650.1582274-9-Jason@zx2c4.com> References: <20220419111650.1582274-1-Jason@zx2c4.com> <20220419111650.1582274-9-Jason@zx2c4.com> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.42.4 (3.42.4-2.fc35) MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-malware-bazaar: not-scanned Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org On Tue, 2022-04-19 at 13:16 +0200, Jason A. Donenfeld wrote: > In the event that random_get_entropy() can't access a cycle counter or > similar, falling back to returning 0 is really not the best we can do. > Instead, at least calling random_get_entropy_fallback() would be > preferable, because that always needs to return _something_, even > falling back to jiffies eventually. It's not as though > random_get_entropy_fallback() is super high precision or guaranteed to > be entropic, but basically anything that's not zero all the time is > better than returning zero all the time. > > This is accomplished by just including the asm-generic code like on > other architectures, which means we can get rid of the empty stub > function here. LGTM, actually better than before, though not even sure any drivers in ARCH=um have interrupts that say they can be used for this. Acked-by: Johannes Berg I assume you're going to take this through the random tree? johannes 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 81C86C433F5 for ; Tue, 19 Apr 2022 12:27:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Date:Cc:To:From:Subject:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=6llQBV2kYwNqhFPLGvBw7c4zBB5bp5T4FI5Mxdo6kjs=; b=r6SD6/UnM4ZFBK vVEIPOoV0c+4s3ota6fTdQ7j9XSdurJnp/ArSphDKiWUnZL53jXZSyEQZ6KORKCJbNO02pPBhCLsM rgW0UirS2H5zdUNiCqqoLI/hAnA04kaaoDcHemUKOrTzA5R54reGIKq7jVIeOzUxGwMg50Ylf662k IQmYCxEpbIjV4r6ysN2yfGVSgu8GMfG9wb3Xtel5ZIdE0aujtTxqY1pgfPs/evPxFxhLLkUyUrDZM p/jM7KA2T+4Vzb9ncie5ve0o1xl8dXCJ9dMhMXZQUQxy8XEnGOBuiGr50ZDIiYJE1Fvn+nuv5dMKn q1VP2QmlsQOD792EsvQw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ngmwt-003Tr3-OL; Tue, 19 Apr 2022 12:27:15 +0000 Received: from s3.sipsolutions.net ([2a01:4f8:191:4433::2] helo=sipsolutions.net) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1ngm7b-0039xv-18; Tue, 19 Apr 2022 11:34:20 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sipsolutions.net; s=mail; h=Content-Transfer-Encoding:MIME-Version: Content-Type:References:In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-To: Resent-Cc:Resent-Message-ID; bh=PBEaZlFaHYvw3+tY3UhjQeVca+KaL0Du1BTdeZIcC7U=; t=1650368050; x=1651577650; b=VVIm3MbmHnnqqslYSRoyalByghZkGUkNvNHMGV0xdhaUkvA oso7l21/9A7GqCzmwGW4o2A7BTeGgpXxE4pSB1rHERQ+i6v0SC6XfLuK79YdTgRpPlbMuD4xQmnIt J7bdG1bfPtRfGP67SCvYxturQOKiOPfIMd6a3FG5euECEla7xkbYGgxA1WoP8MrZw4Xar2aeFN8Fu TNGG/75Bbi8wSG6iqfwOq/G3r8isyM1EyP2+s5oCX6p3RdvwI2JMh6G8cDPr1pEsjsLHvtDDC06kP buzNPn3rmWWw5yLwhEoOZxFEYwPY/nrVdKJUL9Psv1VywK743Gw14IJRrAaPv92A==; Received: by sipsolutions.net with esmtpsa (TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.95) (envelope-from ) id 1ngm6l-00BueY-OI; Tue, 19 Apr 2022 13:33:23 +0200 Message-ID: <694c2318d98973ee8995e891f81216ad267341dc.camel@sipsolutions.net> Subject: Re: [PATCH v5 08/11] um: use fallback for random_get_entropy() instead of zero From: Johannes Berg To: "Jason A. Donenfeld" , linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org, tglx@linutronix.de, arnd@arndb.de Cc: Theodore Ts'o , Dominik Brodowski , Russell King , Catalin Marinas , Will Deacon , Geert Uytterhoeven , Thomas Bogendoerfer , Paul Walmsley , Palmer Dabbelt , Albert Ou , "David S . Miller" , Richard Weinberger , Anton Ivanov , Ingo Molnar , Borislav Petkov , Dave Hansen , "H . Peter Anvin" , Chris Zankel , Max Filippov , Stephen Boyd , Dinh Nguyen , linux-arm-kernel@lists.infradead.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-riscv@lists.infradead.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org, x86@kernel.org, linux-xtensa@linux-xtensa.org Date: Tue, 19 Apr 2022 13:33:21 +0200 In-Reply-To: <20220419111650.1582274-9-Jason@zx2c4.com> References: <20220419111650.1582274-1-Jason@zx2c4.com> <20220419111650.1582274-9-Jason@zx2c4.com> User-Agent: Evolution 3.42.4 (3.42.4-2.fc35) MIME-Version: 1.0 X-malware-bazaar: not-scanned X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220419_043415_138405_6756CEB1 X-CRM114-Status: GOOD ( 13.66 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On Tue, 2022-04-19 at 13:16 +0200, Jason A. Donenfeld wrote: > In the event that random_get_entropy() can't access a cycle counter or > similar, falling back to returning 0 is really not the best we can do. > Instead, at least calling random_get_entropy_fallback() would be > preferable, because that always needs to return _something_, even > falling back to jiffies eventually. It's not as though > random_get_entropy_fallback() is super high precision or guaranteed to > be entropic, but basically anything that's not zero all the time is > better than returning zero all the time. > > This is accomplished by just including the asm-generic code like on > other architectures, which means we can get rid of the empty stub > function here. LGTM, actually better than before, though not even sure any drivers in ARCH=um have interrupts that say they can be used for this. Acked-by: Johannes Berg I assume you're going to take this through the random tree? johannes _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 16761C433FE for ; Tue, 19 Apr 2022 12:27:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Date:Cc:To:From:Subject:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=sN8q5d5z70wdymfCZBecK5tGmW4Sco0sQqJ3PmlsGW8=; b=FE9pTXX73+KSJw HmX+yhksmWh9x9OWFCbTmDuzXXrZBN8gLwcfs6pIhvhwx5Jj7Qj2QGzr98a0CKoO9weX7FaQvHal9 u9aTTApBsLRQx6KtJECR6Go1+aHMM1YuyMcaJ+cczSz1vZM3Iz07dI9QQt/2c9gHQp/Ucv/Kj6NwZ sn+KH0iZdnqitSDCFKC1acK6WRwT1yFmAYwsU1k+EgiH9AK2W+bwrUQFI0gNezMuzalueEagt8vHh WGSRXjrc2zax9Fn1k0fltKE5uwzILVcAgh6JD52bK2kHHbptoxGqlEW1oP31xs5hToSgLzEmWf8am rmnBucdBVzYFr6j6Tazw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ngmvS-003TIw-2w; Tue, 19 Apr 2022 12:25:48 +0000 Received: from s3.sipsolutions.net ([2a01:4f8:191:4433::2] helo=sipsolutions.net) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1ngm7b-0039xv-18; Tue, 19 Apr 2022 11:34:20 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sipsolutions.net; s=mail; h=Content-Transfer-Encoding:MIME-Version: Content-Type:References:In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-To: Resent-Cc:Resent-Message-ID; bh=PBEaZlFaHYvw3+tY3UhjQeVca+KaL0Du1BTdeZIcC7U=; t=1650368050; x=1651577650; b=VVIm3MbmHnnqqslYSRoyalByghZkGUkNvNHMGV0xdhaUkvA oso7l21/9A7GqCzmwGW4o2A7BTeGgpXxE4pSB1rHERQ+i6v0SC6XfLuK79YdTgRpPlbMuD4xQmnIt J7bdG1bfPtRfGP67SCvYxturQOKiOPfIMd6a3FG5euECEla7xkbYGgxA1WoP8MrZw4Xar2aeFN8Fu TNGG/75Bbi8wSG6iqfwOq/G3r8isyM1EyP2+s5oCX6p3RdvwI2JMh6G8cDPr1pEsjsLHvtDDC06kP buzNPn3rmWWw5yLwhEoOZxFEYwPY/nrVdKJUL9Psv1VywK743Gw14IJRrAaPv92A==; Received: by sipsolutions.net with esmtpsa (TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.95) (envelope-from ) id 1ngm6l-00BueY-OI; Tue, 19 Apr 2022 13:33:23 +0200 Message-ID: <694c2318d98973ee8995e891f81216ad267341dc.camel@sipsolutions.net> Subject: Re: [PATCH v5 08/11] um: use fallback for random_get_entropy() instead of zero From: Johannes Berg To: "Jason A. Donenfeld" , linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org, tglx@linutronix.de, arnd@arndb.de Cc: Theodore Ts'o , Dominik Brodowski , Russell King , Catalin Marinas , Will Deacon , Geert Uytterhoeven , Thomas Bogendoerfer , Paul Walmsley , Palmer Dabbelt , Albert Ou , "David S . Miller" , Richard Weinberger , Anton Ivanov , Ingo Molnar , Borislav Petkov , Dave Hansen , "H . Peter Anvin" , Chris Zankel , Max Filippov , Stephen Boyd , Dinh Nguyen , linux-arm-kernel@lists.infradead.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-riscv@lists.infradead.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org, x86@kernel.org, linux-xtensa@linux-xtensa.org Date: Tue, 19 Apr 2022 13:33:21 +0200 In-Reply-To: <20220419111650.1582274-9-Jason@zx2c4.com> References: <20220419111650.1582274-1-Jason@zx2c4.com> <20220419111650.1582274-9-Jason@zx2c4.com> User-Agent: Evolution 3.42.4 (3.42.4-2.fc35) MIME-Version: 1.0 X-malware-bazaar: not-scanned X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220419_043415_138405_6756CEB1 X-CRM114-Status: GOOD ( 13.66 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, 2022-04-19 at 13:16 +0200, Jason A. Donenfeld wrote: > In the event that random_get_entropy() can't access a cycle counter or > similar, falling back to returning 0 is really not the best we can do. > Instead, at least calling random_get_entropy_fallback() would be > preferable, because that always needs to return _something_, even > falling back to jiffies eventually. It's not as though > random_get_entropy_fallback() is super high precision or guaranteed to > be entropic, but basically anything that's not zero all the time is > better than returning zero all the time. > > This is accomplished by just including the asm-generic code like on > other architectures, which means we can get rid of the empty stub > function here. LGTM, actually better than before, though not even sure any drivers in ARCH=um have interrupts that say they can be used for this. Acked-by: Johannes Berg I assume you're going to take this through the random tree? johannes _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel