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 CBB96C433F5 for ; Tue, 24 May 2022 18:53:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240486AbiEXSxt (ORCPT ); Tue, 24 May 2022 14:53:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43954 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240460AbiEXSxh (ORCPT ); Tue, 24 May 2022 14:53:37 -0400 Received: from mail.skyhub.de (mail.skyhub.de [5.9.137.197]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 85A9857B01 for ; Tue, 24 May 2022 11:53:33 -0700 (PDT) Received: from zn.tnic (p200300ea974657c6329c23fffea6a903.dip0.t-ipconnect.de [IPv6:2003:ea:9746:57c6:329c: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 22FE81EC0622; Tue, 24 May 2022 20:53:32 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1653418412; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=2M9QqqRLgX47depXRiMTQ6cBUd+HXGc9LcO2mQh+QJw=; b=SmoLtmPmAbF13I1yW9wrv0Q5YztH/n6IHFGKodaR7ouySLSF1qc4J87FrytACnl2rt1Bjo vBaomNdkeCq8Du2G1gBXSLtAx18DTBvW7AN4Bd0cyEHg5jGZUXLfhYuuHZXUmdQw00DIfq TMibL4vCNCKDJVm0M40jzZCVFChWi+Y= From: Borislav Petkov To: X86 ML Cc: LKML Subject: [RFC PATCH 3/3] x86/microcode: Taint and warn on late loading Date: Tue, 24 May 2022 20:53:24 +0200 Message-Id: <20220524185324.28395-4-bp@alien8.de> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220524185324.28395-1-bp@alien8.de> References: <20220524185324.28395-1-bp@alien8.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Borislav Petkov Warn when done and taint the kernel. Signed-off-by: Borislav Petkov --- arch/x86/kernel/cpu/microcode/core.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c index c717db6b6856..f7ded2facaa0 100644 --- a/arch/x86/kernel/cpu/microcode/core.c +++ b/arch/x86/kernel/cpu/microcode/core.c @@ -501,6 +501,8 @@ static int microcode_reload_late(void) microcode_check(); pr_info("Reload completed, microcode revision: 0x%x\n", boot_cpu_data.microcode); + pr_err("However, late loading is dangerous and it taints the kernel.\n" + "You should switch to early loading, if possible.\n"); return ret; } @@ -541,6 +543,8 @@ static ssize_t reload_store(struct device *dev, if (ret == 0) ret = size; + add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_STILL_OK); + return ret; } -- 2.35.1