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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3B20EC43331 for ; Tue, 12 Nov 2019 23:52:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1DB05214E0 for ; Tue, 12 Nov 2019 23:52:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727563AbfKLXwI (ORCPT ); Tue, 12 Nov 2019 18:52:08 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:57300 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726960AbfKLXuf (ORCPT ); Tue, 12 Nov 2019 18:50:35 -0500 Received: from [167.98.27.226] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1iUfvd-0008I7-Lk; Tue, 12 Nov 2019 23:50:33 +0000 Received: from ben by deadeye with local (Exim 4.93-RC1) (envelope-from ) id 1iUfvc-000573-K7; Tue, 12 Nov 2019 23:50:32 +0000 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Borislav Petkov" , "Josh Poimboeuf" , "Thomas Gleixner" , "Tony Luck" , "Pawan Gupta" Date: Tue, 12 Nov 2019 23:48:06 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 09/25] x86/tsx: Add "auto" option to the tsx= cmdline parameter In-Reply-To: X-SA-Exim-Connect-IP: 167.98.27.226 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.77-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Pawan Gupta commit 7531a3596e3272d1f6841e0d601a614555dc6b65 upstream. Platforms which are not affected by X86_BUG_TAA may want the TSX feature enabled. Add "auto" option to the TSX cmdline parameter. When tsx=auto disable TSX when X86_BUG_TAA is present, otherwise enable TSX. More details on X86_BUG_TAA can be found here: https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/tsx_async_abort.html [ bp: Extend the arg buffer to accommodate "auto\0". ] Signed-off-by: Pawan Gupta Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Reviewed-by: Tony Luck Reviewed-by: Josh Poimboeuf [bwh: Backported to 4.4: adjust filename] Signed-off-by: Ben Hutchings --- Documentation/kernel-parameters.txt | 3 +++ arch/x86/kernel/cpu/tsx.c | 7 ++++++- 2 files changed, 9 insertions(+), 1 deletion(-) --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -3602,6 +3602,9 @@ bytes respectively. Such letter suffixes update. This new MSR allows for the reliable deactivation of the TSX functionality.) + auto - Disable TSX if X86_BUG_TAA is present, + otherwise enable TSX on the system. + Not specifying this option is equivalent to tsx=off. See Documentation/hw-vuln/tsx_async_abort.rst --- a/arch/x86/kernel/cpu/tsx.c +++ b/arch/x86/kernel/cpu/tsx.c @@ -75,7 +75,7 @@ static bool __init tsx_ctrl_is_supported void __init tsx_init(void) { - char arg[4] = {}; + char arg[5] = {}; int ret; if (!tsx_ctrl_is_supported()) @@ -87,6 +87,11 @@ void __init tsx_init(void) tsx_ctrl_state = TSX_CTRL_ENABLE; } else if (!strcmp(arg, "off")) { tsx_ctrl_state = TSX_CTRL_DISABLE; + } else if (!strcmp(arg, "auto")) { + if (boot_cpu_has_bug(X86_BUG_TAA)) + tsx_ctrl_state = TSX_CTRL_DISABLE; + else + tsx_ctrl_state = TSX_CTRL_ENABLE; } else { tsx_ctrl_state = TSX_CTRL_DISABLE; pr_err("tsx: invalid option, defaulting to off\n");