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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,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 B12F7ECE564 for ; Tue, 18 Sep 2018 20:46:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 67BCE2146D for ; Tue, 18 Sep 2018 20:46:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 67BCE2146D 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 S1730561AbeISCVM (ORCPT ); Tue, 18 Sep 2018 22:21:12 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:58778 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729824AbeISCVM (ORCPT ); Tue, 18 Sep 2018 22:21:12 -0400 Received: from p5492e4c1.dip0.t-ipconnect.de ([84.146.228.193] helo=nanos) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1g2MtX-0002na-CO; Tue, 18 Sep 2018 22:46:51 +0200 Date: Tue, 18 Sep 2018 22:46:50 +0200 (CEST) From: Thomas Gleixner To: "Eric W. Biederman" cc: LKML , linux-arch@vger.kernel.org, Ingo Molnar , x86@kernel.org, Dave Hansen Subject: Re: [REVIEW][PATCH 15/20] signal/x86: Don't compute pkey in __do_page_fault In-Reply-To: <20180918000546.12552-15-ebiederm@xmission.com> Message-ID: References: <87y3bzk6yv.fsf@xmission.com> <20180918000546.12552-15-ebiederm@xmission.com> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 18 Sep 2018, Eric W. Biederman wrote: > There are no more users of the computed pkey value in __do_page_fault > so stop computing the value. > > Signed-off-by: "Eric W. Biederman" Reviewed-by: Thomas Gleixner > --- > arch/x86/mm/fault.c | 4 ---- > 1 file changed, 4 deletions(-) > > diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c > index 7ba00519fa5d..f82106578364 100644 > --- a/arch/x86/mm/fault.c > +++ b/arch/x86/mm/fault.c > @@ -1215,7 +1215,6 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code, > struct mm_struct *mm; > vm_fault_t fault, major = 0; > unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; > - u32 pkey; > > tsk = current; > mm = tsk->mm; > @@ -1387,10 +1386,7 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code, > * (potentially after handling any pending signal during the return to > * userland). The return to userland is identified whenever > * FAULT_FLAG_USER|FAULT_FLAG_KILLABLE are both set in flags. > - * Thus we have to be careful about not touching vma after handling the > - * fault, so we read the pkey beforehand. > */ > - pkey = vma_pkey(vma); > fault = handle_mm_fault(vma, address, flags); > major |= fault & VM_FAULT_MAJOR; > > -- > 2.17.1 > >