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=-12.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 A8301C43219 for ; Tue, 30 Apr 2019 11:30:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 73A8820675 for ; Tue, 30 Apr 2019 11:30:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b="NUXAOg55" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727978AbfD3Laq (ORCPT ); Tue, 30 Apr 2019 07:30:46 -0400 Received: from terminus.zytor.com ([198.137.202.136]:34359 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726202AbfD3Lap (ORCPT ); Tue, 30 Apr 2019 07:30:45 -0400 Received: from terminus.zytor.com (localhost [127.0.0.1]) by terminus.zytor.com (8.15.2/8.15.2) with ESMTPS id x3UBUEME1350830 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Tue, 30 Apr 2019 04:30:14 -0700 DKIM-Filter: OpenDKIM Filter v2.11.0 terminus.zytor.com x3UBUEME1350830 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2019041745; t=1556623815; bh=WhZbhuJokP1cXy8dq38BMW62S+nhjuqIofFpVeNtwlQ=; h=Date:From:Cc:Reply-To:In-Reply-To:References:To:Subject:From; b=NUXAOg55Kzf7uIAgTL+FyaFBlKrz37KJiHDG1ojJh7ufwY0QeJFI61DKfNNqmmMS4 b6WocASQT10yd3d71erhssxC1uunXAZneiFIPCLJ18jA7mSNsVdqsXP4u44cMI+qCq ZZlsBkHlKWl6enDEUqSob8n6v9kknJsAtRMYYc6/8+dhZwkjMU84bniqHFu3/IXkB9 Z9t0LA5nPJHKgIbzc1tzOOfmiGcVgiCWCo3wA/PpGmWzWS4Hf6ORGuqk1XIuQT+5M0 8ROB2KsqZyXCnsH1feWvV1BWGYkx0akOFfWF4MyZTOg+s8ITwDBs+S84w0VmCHm8Y1 a/myCNAbLxgCA== Received: (from tipbot@localhost) by terminus.zytor.com (8.15.2/8.15.2/Submit) id x3UBUDqN1350825; Tue, 30 Apr 2019 04:30:13 -0700 Date: Tue, 30 Apr 2019 04:30:13 -0700 X-Authentication-Warning: terminus.zytor.com: tipbot set sender to tipbot@zytor.com using -f From: tip-bot for Sebastian Andrzej Siewior Message-ID: Cc: luto@kernel.org, bp@alien8.de, fenghua.yu@intel.com, hpa@zytor.com, mingo@kernel.org, torvalds@linux-foundation.org, bigeasy@linutronix.de, peterz@infradead.org, tglx@linutronix.de, dave.hansen@intel.com, linux-kernel@vger.kernel.org, oleg@redhat.com Reply-To: hpa@zytor.com, bp@alien8.de, fenghua.yu@intel.com, luto@kernel.org, peterz@infradead.org, torvalds@linux-foundation.org, bigeasy@linutronix.de, mingo@kernel.org, tglx@linutronix.de, oleg@redhat.com, linux-kernel@vger.kernel.org, dave.hansen@intel.com In-Reply-To: <20190430083126.rilbb76yc27vrem5@linutronix.de> References: <20190430083126.rilbb76yc27vrem5@linutronix.de> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/fpu] x86/fpu: Remove unnecessary saving of FPU registers in copy_fpstate_to_sigframe() Git-Commit-ID: 531bd721812cad4b7f7158b246fba8303b555be7 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 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 531bd721812cad4b7f7158b246fba8303b555be7 Gitweb: https://git.kernel.org/tip/531bd721812cad4b7f7158b246fba8303b555be7 Author: Sebastian Andrzej Siewior AuthorDate: Tue, 30 Apr 2019 10:31:26 +0200 Committer: Ingo Molnar CommitDate: Tue, 30 Apr 2019 13:07:54 +0200 x86/fpu: Remove unnecessary saving of FPU registers in copy_fpstate_to_sigframe() Since commit: eeec00d73be2e ("x86/fpu: Fault-in user stack if copy_fpstate_to_sigframe() fails") there is no need to have FPU registers saved if copy_fpregs_to_sigframe() fails, because we retry it after we resolved the fault condition. Saving the registers is not wrong but it is not necessary and it forces us to load the FPU registers on the retry attempt. Don't save the FPU registers if copy_fpstate_to_sigframe() fails. Signed-off-by: Sebastian Andrzej Siewior Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Dave Hansen Cc: Fenghua Yu Cc: H. Peter Anvin Cc: Jason@zx2c4.com Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: bp@suse.de Cc: jannh@google.com Cc: kurt.kanzenbach@linutronix.de Cc: kvm@vger.kernel.org Cc: pbonzini@redhat.com Cc: riel@surriel.com Cc: rkrcmar@redhat.com Link: http://lkml.kernel.org/r/20190430083126.rilbb76yc27vrem5@linutronix.de Signed-off-by: Ingo Molnar --- arch/x86/kernel/fpu/signal.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c index 6d6c2d6afde4..08c5059dc4ec 100644 --- a/arch/x86/kernel/fpu/signal.c +++ b/arch/x86/kernel/fpu/signal.c @@ -157,10 +157,9 @@ static inline int copy_fpregs_to_sigframe(struct xregs_state __user *buf) */ int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size) { - struct fpu *fpu = ¤t->thread.fpu; struct task_struct *tsk = current; int ia32_fxstate = (buf != buf_fx); - int ret = -EFAULT; + int ret; ia32_fxstate &= (IS_ENABLED(CONFIG_X86_32) || IS_ENABLED(CONFIG_IA32_EMULATION)); @@ -187,9 +186,6 @@ retry: pagefault_disable(); ret = copy_fpregs_to_sigframe(buf_fx); pagefault_enable(); - if (ret && !test_thread_flag(TIF_NEED_FPU_LOAD)) - copy_fpregs_to_fpstate(fpu); - set_thread_flag(TIF_NEED_FPU_LOAD); fpregs_unlock(); if (ret) {