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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 465BAC04AB6 for ; Fri, 31 May 2019 09:10:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1C15C26678 for ; Fri, 31 May 2019 09:10:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726579AbfEaJKC (ORCPT ); Fri, 31 May 2019 05:10:02 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:48354 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726002AbfEaJKC (ORCPT ); Fri, 31 May 2019 05:10:02 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id ACD39341; Fri, 31 May 2019 02:10:01 -0700 (PDT) Received: from [10.162.42.223] (p8cg001049571a15.blr.arm.com [10.162.42.223]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 2CF433F59C; Fri, 31 May 2019 02:09:58 -0700 (PDT) Subject: Re: [PATCH 3/4] arm64/mm: Consolidate page fault information capture To: Mark Rutland Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Catalin Marinas , Will Deacon , James Morse , Andrey Konovalov References: <1559133285-27986-1-git-send-email-anshuman.khandual@arm.com> <1559133285-27986-4-git-send-email-anshuman.khandual@arm.com> <20190529145312.GG31777@lakrids.cambridge.arm.com> From: Anshuman Khandual Message-ID: <4d799bda-dfde-8ba5-9aeb-aa38550f6103@arm.com> Date: Fri, 31 May 2019 14:40:13 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20190529145312.GG31777@lakrids.cambridge.arm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/29/2019 08:23 PM, Mark Rutland wrote: > On Wed, May 29, 2019 at 06:04:44PM +0530, Anshuman Khandual wrote: >> This consolidates page fault information capture and move them bit earlier. >> While here it also adds an wrapper is_write_abort(). It also saves some >> cycles by replacing multiple user_mode() calls into a single one earlier >> during the fault. > > To be honest, I doubt this has any measureable impact, but I agree that > using variables _may_ make the flow control easier to understand. > >> >> Signed-off-by: Anshuman Khandual >> Cc: Catalin Marinas >> Cc: Will Deacon >> Cc: Mark Rutland >> Cc: James Morse >> Cc: Andrey Konovalov >> --- >> arch/arm64/mm/fault.c | 22 +++++++++++++++------- >> 1 file changed, 15 insertions(+), 7 deletions(-) >> >> diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c >> index da02678..170c71f 100644 >> --- a/arch/arm64/mm/fault.c >> +++ b/arch/arm64/mm/fault.c >> @@ -435,6 +435,11 @@ static bool is_el0_instruction_abort(unsigned int esr) >> return ESR_ELx_EC(esr) == ESR_ELx_EC_IABT_LOW; >> } >> >> +static bool is_write_abort(unsigned int esr) >> +{ >> + return (esr & ESR_ELx_WNR) && !(esr & ESR_ELx_CM); >> +} > > In off-list review, I mentioned that this isn't true for EL1, and I > think that we should name this 'is_el0_write_abort()' or add a comment > explaining the caveats if factored into a helper. > > Thanks, > Mark. Okay will change the wrapper name to is_el0_write_abort() and add a comment explaining how this is only applicable to aborts originating from EL0.