From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754850AbcK2S3D (ORCPT ); Tue, 29 Nov 2016 13:29:03 -0500 Received: from terminus.zytor.com ([198.137.202.10]:41478 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751765AbcK2S2y (ORCPT ); Tue, 29 Nov 2016 13:28:54 -0500 Date: Tue, 29 Nov 2016 10:28:02 -0800 From: tip-bot for Thomas Gleixner Message-ID: Cc: yinghai@kernel.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, peterz@infradead.org, hpa@zytor.com, mingo@kernel.org, bp@alien8.de Reply-To: hpa@zytor.com, tglx@linutronix.de, peterz@infradead.org, yinghai@kernel.org, linux-kernel@vger.kernel.org, mingo@kernel.org, bp@alien8.de In-Reply-To: <20161119134017.483561692@linutronix.de> References: <20161119134017.483561692@linutronix.de> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/timers] x86/tsc: Use X86_FEATURE_TSC_ADJUST in detect_art() Git-Commit-ID: 7b3d2f6e08ed5eb6bcf6912938f7a542405f8e8e X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 7b3d2f6e08ed5eb6bcf6912938f7a542405f8e8e Gitweb: http://git.kernel.org/tip/7b3d2f6e08ed5eb6bcf6912938f7a542405f8e8e Author: Thomas Gleixner AuthorDate: Sat, 19 Nov 2016 13:47:33 +0000 Committer: Thomas Gleixner CommitDate: Tue, 29 Nov 2016 19:23:15 +0100 x86/tsc: Use X86_FEATURE_TSC_ADJUST in detect_art() The art detection uses rdmsrl_safe() to detect the availablity of the TSC_ADJUST MSR. That's pointless because we have a feature bit for this. Use it. Signed-off-by: Thomas Gleixner Reviewed-by: Ingo Molnar Cc: Peter Zijlstra Cc: Yinghai Lu Cc: Borislav Petkov Link: http://lkml.kernel.org/r/20161119134017.483561692@linutronix.de Signed-off-by: Thomas Gleixner --- arch/x86/kernel/tsc.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index 0ff1ec6..2b27c5a 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -1057,18 +1057,20 @@ static void detect_art(void) if (boot_cpu_data.cpuid_level < ART_CPUID_LEAF) return; - cpuid(ART_CPUID_LEAF, &art_to_tsc_denominator, - &art_to_tsc_numerator, unused, unused+1); - - /* Don't enable ART in a VM, non-stop TSC required */ + /* Don't enable ART in a VM, non-stop TSC and TSC_ADJUST required */ if (boot_cpu_has(X86_FEATURE_HYPERVISOR) || !boot_cpu_has(X86_FEATURE_NONSTOP_TSC) || - art_to_tsc_denominator < ART_MIN_DENOMINATOR) + !boot_cpu_has(X86_FEATURE_TSC_ADJUST)) return; - if (rdmsrl_safe(MSR_IA32_TSC_ADJUST, &art_to_tsc_offset)) + cpuid(ART_CPUID_LEAF, &art_to_tsc_denominator, + &art_to_tsc_numerator, unused, unused+1); + + if (art_to_tsc_denominator < ART_MIN_DENOMINATOR) return; + rdmsrl(MSR_IA32_TSC_ADJUST, art_to_tsc_offset); + /* Make this sticky over multiple CPU init calls */ setup_force_cpu_cap(X86_FEATURE_ART); }