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 9E685C43334 for ; Tue, 5 Jul 2022 19:36:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232665AbiGETgd (ORCPT ); Tue, 5 Jul 2022 15:36:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37086 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230135AbiGETgb (ORCPT ); Tue, 5 Jul 2022 15:36:31 -0400 Received: from mail.skyhub.de (mail.skyhub.de [5.9.137.197]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5F5FE13FB2; Tue, 5 Jul 2022 12:36:30 -0700 (PDT) Received: from zn.tnic (p200300ea970ff625329c23fffea6a903.dip0.t-ipconnect.de [IPv6:2003:ea:970f:f625:329c:23ff:fea6:a903]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id DE0E71EC0628; Tue, 5 Jul 2022 21:36:24 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1657049785; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=s8J8d5ZD1NtUU5JRSS/ItcYuS6F4P47XpllivMzf87o=; b=CYAJFqLPSx1ehm7wcUphSX9EWalTFYzy2s5e2vW1knuJ2MgMxhOyXFZiKJxRnn65i1LTXx z6QxxfrgCmuNCUqEFoukAoKTL/2V6JEeQCCX4HCRrDpCeDWCRbeLyIZPGE82Hs3kg+czu+ 9EUDiQHULEW8UFb3P8zZIkSHwIX4AB8= Date: Tue, 5 Jul 2022 21:36:20 +0200 From: Borislav Petkov To: "Jason A. Donenfeld" Cc: linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, x86@kernel.org, Catalin Marinas , Will Deacon , Michael Ellerman , Heiko Carstens , Alexander Gordeev , Thomas Gleixner , "H . Peter Anvin" , Greg Kroah-Hartman , Arnd Bergmann Subject: Re: [PATCH] random: remove CONFIG_ARCH_RANDOM and "nordrand" Message-ID: References: <20220705190121.293703-1-Jason@zx2c4.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20220705190121.293703-1-Jason@zx2c4.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 05, 2022 at 09:01:21PM +0200, Jason A. Donenfeld wrote: > @@ -26,7 +18,6 @@ __setup("nordrand", x86_rdrand_setup); > */ > #define SANITY_CHECK_LOOPS 8 > > -#ifdef CONFIG_ARCH_RANDOM > void x86_init_rdrand(struct cpuinfo_x86 *c) > { > unsigned int changed = 0; > @@ -59,8 +50,6 @@ void x86_init_rdrand(struct cpuinfo_x86 *c) > } > > if (WARN_ON_ONCE(!changed)) > - pr_emerg( > -"RDRAND gives funky smelling output, might consider not using it by booting with \"nordrand\""); > + pr_emerg("RDRAND gives funky smelling output; update microcode or firmware."); It is highly unlikely to get a BIOS or microcode update for that matter, for old systems: 7879fc4bdc75 ("x86/rdrand: Sanity-check RDRAND output") so I guess here you're better off saying that the kernel simply disables rdrand support and do clear_cpu_cap(c, X86_FEATURE_RDRAND); here too. If I read the commit message above correctly, it sounds like RDRAND output is not that important anyway... Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette