From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932091AbcAXWi3 (ORCPT ); Sun, 24 Jan 2016 17:38:29 -0500 Received: from mail.kernel.org ([198.145.29.136]:41826 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755412AbcAXWiU (ORCPT ); Sun, 24 Jan 2016 17:38:20 -0500 From: Andy Lutomirski To: x86@kernel.org, linux-kernel@vger.kernel.org Cc: Borislav Petkov , Fenghua Yu , Oleg Nesterov , Peter Zijlstra , Sai Praneeth Prakhya , yu-cheng yu , Dave Hansen , Rik van Riel , Linus Torvalds , Andy Lutomirski Subject: [PATCH v2 4/5] x86/fpu: Speed up lazy FPU restores slightly Date: Sun, 24 Jan 2016 14:38:09 -0800 Message-Id: <980004297e233c27066d54e71382c44cdd36ef7c.1453675014.git.luto@kernel.org> X-Mailer: git-send-email 2.5.0 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If we have an FPU, there's no need to check CR0 for FPU emulation. Signed-off-by: Andy Lutomirski --- 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 87f80febf477..36a9c017540e 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); -- 2.5.0