Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S947641AbcJaWUz (ORCPT ); Mon, 31 Oct 2016 18:20:55 -0400 Received: from mail.kernel.org ([198.145.29.136]:39166 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S947498AbcJaWTA (ORCPT ); Mon, 31 Oct 2016 18:19:00 -0400 From: Andy Lutomirski To: x86@kernel.org Cc: Borislav Petkov , linux-kernel@vger.kernel.org, Rusty Russell , Paolo Bonzini , Rik van Riel , kvm list , Andy Lutomirski Subject: [PATCH 2/8] fpu/bugs: Stop saving and restoring CR0.TS in fpu__init_check_bugs() Date: Mon, 31 Oct 2016 15:18:43 -0700 Message-Id: <76d1f1eacb5caead98197d1eb50ac6110ab20c6a.1477951965.git.luto@kernel.org> X-Mailer: git-send-email 2.7.4 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 Content-Length: 1167 Lines: 43 fpu__init_check_bugs() runs long after the early FPU init, so CR0.TS will be clear by the time it runs. The save-and-restore dance would have been unnecessary anyway, though, as kernel_fpu_begin() would have been good enough. Signed-off-by: Andy Lutomirski --- arch/x86/kernel/fpu/bugs.c | 7 ------- 1 file changed, 7 deletions(-) diff --git a/arch/x86/kernel/fpu/bugs.c b/arch/x86/kernel/fpu/bugs.c index aad34aafc0e0..d913047f832c 100644 --- a/arch/x86/kernel/fpu/bugs.c +++ b/arch/x86/kernel/fpu/bugs.c @@ -23,17 +23,12 @@ static double __initdata y = 3145727.0; */ void __init fpu__init_check_bugs(void) { - u32 cr0_saved; s32 fdiv_bug; /* kernel_fpu_begin/end() relies on patched alternative instructions. */ if (!boot_cpu_has(X86_FEATURE_FPU)) return; - /* We might have CR0::TS set already, clear it: */ - cr0_saved = read_cr0(); - write_cr0(cr0_saved & ~X86_CR0_TS); - kernel_fpu_begin(); /* @@ -56,8 +51,6 @@ void __init fpu__init_check_bugs(void) kernel_fpu_end(); - write_cr0(cr0_saved); - if (fdiv_bug) { set_cpu_bug(&boot_cpu_data, X86_BUG_FDIV); pr_warn("Hmm, FPU with FDIV bug\n"); -- 2.7.4