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=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_MUTT 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 C02BAC282CE for ; Tue, 4 Jun 2019 14:42:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8A08E212F5 for ; Tue, 4 Jun 2019 14:42:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727757AbfFDOmO (ORCPT ); Tue, 4 Jun 2019 10:42:14 -0400 Received: from foss.arm.com ([217.140.101.70]:45466 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727182AbfFDOmO (ORCPT ); Tue, 4 Jun 2019 10:42:14 -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 9F094A78; Tue, 4 Jun 2019 07:42:13 -0700 (PDT) Received: from arrakis.emea.arm.com (arrakis.cambridge.arm.com [10.1.196.78]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4656E3F690; Tue, 4 Jun 2019 07:42:12 -0700 (PDT) Date: Tue, 4 Jun 2019 15:42:09 +0100 From: Catalin Marinas To: Anshuman Khandual Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Will Deacon , Mark Rutland , James Morse , Andrey Konovalov Subject: Re: [PATCH V2 3/4] arm64/mm: Consolidate page fault information capture Message-ID: <20190604144209.GJ6610@arrakis.emea.arm.com> References: <1559544085-7502-1-git-send-email-anshuman.khandual@arm.com> <1559544085-7502-4-git-send-email-anshuman.khandual@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1559544085-7502-4-git-send-email-anshuman.khandual@arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 03, 2019 at 12:11:24PM +0530, Anshuman Khandual wrote: > diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c > index da02678..4bb65f3 100644 > --- a/arch/arm64/mm/fault.c > +++ b/arch/arm64/mm/fault.c > @@ -435,6 +435,14 @@ static bool is_el0_instruction_abort(unsigned int esr) > return ESR_ELx_EC(esr) == ESR_ELx_EC_IABT_LOW; > } > > +/* > + * This is applicable only for EL0 write aborts. > + */ > +static bool is_el0_write_abort(unsigned int esr) > +{ > + return (esr & ESR_ELx_WNR) && !(esr & ESR_ELx_CM); > +} What makes this EL0 only? > + > static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, > struct pt_regs *regs) > { > @@ -443,6 +451,9 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, > vm_fault_t fault, major = 0; > unsigned long vm_flags = VM_READ | VM_WRITE; > unsigned int mm_flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; > + bool is_user = user_mode(regs); > + bool is_el0_exec = is_el0_instruction_abort(esr); > + bool is_el0_write = is_el0_write_abort(esr); > > if (notify_page_fault(regs, esr)) > return 0; > @@ -454,12 +465,12 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, > if (faulthandler_disabled() || !mm) > goto no_context; > > - if (user_mode(regs)) > + if (is_user) > mm_flags |= FAULT_FLAG_USER; > > - if (is_el0_instruction_abort(esr)) { > + if (is_el0_exec) { > vm_flags = VM_EXEC; > - } else if ((esr & ESR_ELx_WNR) && !(esr & ESR_ELx_CM)) { > + } else if (is_el0_write) { > vm_flags = VM_WRITE; > mm_flags |= FAULT_FLAG_WRITE; > } This can be triggered by an EL1 write to a user mapping, so is_el0_write is misleading. -- Catalin