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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 52BD1C0044C for ; Wed, 7 Nov 2018 19:49:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2622320862 for ; Wed, 7 Nov 2018 19:49:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2622320862 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linutronix.de 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 S1728151AbeKHFVX (ORCPT ); Thu, 8 Nov 2018 00:21:23 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:41970 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727454AbeKHFVW (ORCPT ); Thu, 8 Nov 2018 00:21:22 -0500 Received: from localhost ([127.0.0.1] helo=bazinga.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1gKTpO-00070Q-QI; Wed, 07 Nov 2018 20:49:27 +0100 From: Sebastian Andrzej Siewior To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, Andy Lutomirski , Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , kvm@vger.kernel.org, "Jason A. Donenfeld" , Rik van Riel , Dave Hansen , Sebastian Andrzej Siewior Subject: [PATCH 20/23] x86/fpu: Prepare copy_fpstate_to_sigframe() for TIF_NEED_FPU_LOAD Date: Wed, 7 Nov 2018 20:48:55 +0100 Message-Id: <20181107194858.9380-21-bigeasy@linutronix.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181107194858.9380-1-bigeasy@linutronix.de> References: <20181107194858.9380-1-bigeasy@linutronix.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Rik van Riel The FPU registers need only to be saved if TIF_NEED_FPU_LOAD is not set. Otherwise this has been already done and can be skipped. Signed-off-by: Rik van Riel Signed-off-by: Sebastian Andrzej Siewior --- arch/x86/kernel/fpu/signal.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-) diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c index 254a8dff9cd82..179e2b19976ad 100644 --- a/arch/x86/kernel/fpu/signal.c +++ b/arch/x86/kernel/fpu/signal.c @@ -156,11 +156,20 @@ int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size) sizeof(struct user_i387_ia32_struct), NULL, (struct _fpstate_32 __user *) buf) ? -1 : 1; - /* Update the thread's fxstate to save the fsave header. */ - if (ia32_fxstate) - copy_fxregs_to_kernel(fpu); - else - copy_fpregs_to_fpstate(fpu); + __fpregs_changes_begin(); + /* + * If we do not need to load the FPU registers at return to userspace + * then the CPU has the current state and we need to save it. Otherwise + * it is already done and we can skip it. + */ + if (!test_thread_flag(TIF_NEED_FPU_LOAD)) { + /* Update the thread's fxstate to save the fsave header. */ + if (ia32_fxstate) + copy_fxregs_to_kernel(fpu); + else + copy_fpregs_to_fpstate(fpu); + } + __fpregs_changes_end(); if (using_compacted_format()) { copy_xstate_to_user(buf_fx, xsave, 0, size); -- 2.19.1