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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,T_DKIMWL_WL_HIGH, URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by aws-us-west-2-korg-lkml-1.web.codeaurora.org (Postfix) with ESMTP id 74089C433EF for ; Thu, 14 Jun 2018 14:16:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 20D9720864 for ; Thu, 14 Jun 2018 14:16:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="pRp5zzl2" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 20D9720864 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966308AbeFNOQP (ORCPT ); Thu, 14 Jun 2018 10:16:15 -0400 Received: from mail.kernel.org ([198.145.29.99]:55236 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966288AbeFNONn (ORCPT ); Thu, 14 Jun 2018 10:13:43 -0400 Received: from localhost (LFbn-1-12247-202.w90-92.abo.wanadoo.fr [90.92.61.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0F58B208DB; Thu, 14 Jun 2018 14:13:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1528985622; bh=VnP/QU/3ozkWCPgP8HQNUjF4F134O0gK6YhKoIvvjgU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pRp5zzl2Gd5NRaN3mAjaPKsFu5p0y+18nNQxLL3TbPai6ktN4nUS8qfkIY9EpFVwf gYTNeI6JHEEol+WdNpRmvQIvNvHrLeuXWtXJZ/LDKSNX+MbELIIuAV6W0HnDN/CZ2n KM391dvH7qk9KSaJHDIypSGqIDtQWjGZnfex7xWI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andy Lutomirski , Andy Lutomirski , Borislav Petkov , Brian Gerst , Dave Hansen , Denys Vlasenko , Fenghua Yu , "H. Peter Anvin" , Linus Torvalds , Oleg Nesterov , Peter Zijlstra , Quentin Casasnovas , Sai Praneeth Prakhya , Thomas Gleixner , yu-cheng yu , Ingo Molnar Subject: [PATCH 4.4 07/24] x86/fpu: Fix no387 regression Date: Thu, 14 Jun 2018 16:05:02 +0200 Message-Id: <20180614132724.784717440@linuxfoundation.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180614132724.483802160@linuxfoundation.org> References: <20180614132724.483802160@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Andy Lutomirski commit f363938c70a04e6bc99023a5e0c44ef7879b903f upstream. After fixing FPU option parsing, we now parse the 'no387' boot option too early: no387 clears X86_FEATURE_FPU before it's even probed, so the boot CPU promptly re-enables it. I suspect it gets even more confused on SMP. Fix the probing code to leave X86_FEATURE_FPU off if it's been disabled by setup_clear_cpu_cap(). Signed-off-by: Andy Lutomirski Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: Denys Vlasenko Cc: Fenghua Yu Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Quentin Casasnovas Cc: Sai Praneeth Prakhya Cc: Thomas Gleixner Cc: yu-cheng yu Fixes: 4f81cbafcce2 ("x86/fpu: Fix early FPU command-line parsing") Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/fpu/init.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) --- a/arch/x86/kernel/fpu/init.c +++ b/arch/x86/kernel/fpu/init.c @@ -78,13 +78,15 @@ static void fpu__init_system_early_gener cr0 &= ~(X86_CR0_TS | X86_CR0_EM); write_cr0(cr0); - asm volatile("fninit ; fnstsw %0 ; fnstcw %1" - : "+m" (fsw), "+m" (fcw)); + if (!test_bit(X86_FEATURE_FPU, (unsigned long *)cpu_caps_cleared)) { + asm volatile("fninit ; fnstsw %0 ; fnstcw %1" + : "+m" (fsw), "+m" (fcw)); - if (fsw == 0 && (fcw & 0x103f) == 0x003f) - set_cpu_cap(c, X86_FEATURE_FPU); - else - clear_cpu_cap(c, X86_FEATURE_FPU); + if (fsw == 0 && (fcw & 0x103f) == 0x003f) + set_cpu_cap(c, X86_FEATURE_FPU); + else + clear_cpu_cap(c, X86_FEATURE_FPU); + } #ifndef CONFIG_MATH_EMULATION if (!cpu_has_fpu) {