From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932864AbcBIQM1 (ORCPT ); Tue, 9 Feb 2016 11:12:27 -0500 Received: from terminus.zytor.com ([198.137.202.10]:38573 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932710AbcBIQMX (ORCPT ); Tue, 9 Feb 2016 11:12:23 -0500 Date: Tue, 9 Feb 2016 08:11:16 -0800 From: tip-bot for Andy Lutomirski Message-ID: Cc: bp@alien8.de, fenghua.yu@intel.com, torvalds@linux-foundation.org, quentin.casasnovas@oracle.com, mingo@kernel.org, dave.hansen@linux.intel.com, luto@kernel.org, sai.praneeth.prakhya@intel.com, linux-kernel@vger.kernel.org, oleg@redhat.com, luto@amacapital.net, yu-cheng.yu@intel.com, peterz@infradead.org, riel@redhat.com, tglx@linutronix.de, hpa@zytor.com Reply-To: luto@kernel.org, sai.praneeth.prakhya@intel.com, linux-kernel@vger.kernel.org, oleg@redhat.com, luto@amacapital.net, yu-cheng.yu@intel.com, peterz@infradead.org, riel@redhat.com, tglx@linutronix.de, hpa@zytor.com, bp@alien8.de, fenghua.yu@intel.com, torvalds@linux-foundation.org, quentin.casasnovas@oracle.com, mingo@kernel.org, dave.hansen@linux.intel.com In-Reply-To: <980004297e233c27066d54e71382c44cdd36ef7c.1453675014.git.luto@kernel.org> References: <980004297e233c27066d54e71382c44cdd36ef7c.1453675014.git.luto@kernel.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/fpu] x86/fpu: Speed up lazy FPU restores slightly Git-Commit-ID: c6ab109f7e0eae3bae3bb10f8ddb0df67735c150 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: c6ab109f7e0eae3bae3bb10f8ddb0df67735c150 Gitweb: http://git.kernel.org/tip/c6ab109f7e0eae3bae3bb10f8ddb0df67735c150 Author: Andy Lutomirski AuthorDate: Sun, 24 Jan 2016 14:38:09 -0800 Committer: Ingo Molnar CommitDate: Tue, 9 Feb 2016 15:42:56 +0100 x86/fpu: Speed up lazy FPU restores slightly If we have an FPU, there's no need to check CR0 for FPU emulation. Signed-off-by: Andy Lutomirski Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Dave Hansen Cc: Fenghua Yu Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Quentin Casasnovas Cc: Rik van Riel Cc: Sai Praneeth Prakhya Cc: Thomas Gleixner Cc: yu-cheng yu Link: http://lkml.kernel.org/r/980004297e233c27066d54e71382c44cdd36ef7c.1453675014.git.luto@kernel.org Signed-off-by: Ingo Molnar --- arch/x86/kernel/traps.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 87f80fe..36a9c01 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -752,7 +752,7 @@ do_device_not_available(struct pt_regs *regs, long error_code) RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU"); #ifdef CONFIG_MATH_EMULATION - if (read_cr0() & X86_CR0_EM) { + if (!boot_cpu_has(X86_FEATURE_FPU) && (read_cr0() & X86_CR0_EM)) { struct math_emu_info info = { }; conditional_sti(regs);