From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linutronix.de (193.142.43.55:993) by crypto-ml.lab.linutronix.de with IMAP4-SSL for ; 27 Oct 2019 09:42:30 -0000 Received: from mx2.suse.de ([195.135.220.15] helo=mx1.suse.de) by Galois.linutronix.de with esmtps (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1iOf48-0004Nv-Mp for speck@linutronix.de; Sun, 27 Oct 2019 10:42:29 +0100 Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 62075B208 for ; Sun, 27 Oct 2019 09:42:20 +0000 (UTC) Message-Id: In-Reply-To: References: From: Pawan Gupta Date: Wed, 23 Oct 2019 12:28:57 +0200 Subject: [MODERATED] [PATCH 7/9] TAA v2 7 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit MIME-Version: 1.0 To: speck@linutronix.de List-ID: From: Pawan Gupta Subject: [PATCH 7/9] x86/tsx: Add "auto" option to the tsx= cmdline parameter 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 Reviewed-by: Tony Luck Reviewed-by: Josh Poimboeuf Cc: "H. Peter Anvin" Cc: "Paul E. McKenney" Cc: Andrew Morton Cc: Ingo Molnar Cc: Jonathan Corbet Cc: Juergen Gross Cc: linux-doc@vger.kernel.org Cc: Mark Gross Cc: Mauro Carvalho Chehab Cc: Thomas Gleixner Cc: x86-ml --- Documentation/admin-guide/kernel-parameters.txt | 3 +++ arch/x86/kernel/cpu/tsx.c | 7 ++++++- 2 files changed, 9 insertions(+), 1 deletion(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index af4b1d95b08f..6e548cddb6c3 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -4869,6 +4869,9 @@ 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/admin-guide/hw-vuln/tsx_async_abort.rst diff --git a/arch/x86/kernel/cpu/tsx.c b/arch/x86/kernel/cpu/tsx.c index 04471c4378d8..dda328ec2ba1 100644 --- 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) 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"); -- 2.21.0