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=-3.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 153EBC00A89 for ; Fri, 30 Oct 2020 16:01:57 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7F4582067D for ; Fri, 30 Oct 2020 16:01:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="v/h0a88S" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7F4582067D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=A+AhhWgMGU480W7K/65V/2yxf+MNOwP/Low+5dkgZd4=; b=v/h0a88Sa/aHtNoW/2l8AQ+/F m01qojZIZT/KwY3iCidRDwWTbZIJAbXNF3+YR4QnnG8n57O+f2atqncPOtwkavEDMOxeVk9hKpNnL l1Qi1MGY4+Wn8xaF0yS3gb1crXjy57TLXKlhmwH7+sV4Pp9r3+keBQG7y+038bJWA8vALZtZ/vdv7 AdhJGK62n/mUn3W2pHJEQSDrv0OfhyP0SM9eDHK3pJvvoSuSVIdmI3/4cYnRBBWKQSuMf5cw5XOyT Kxo1AbLzEgP6tNk8HZSTWdHy/SC4YWYdxSujMSF9DzTsW0XFrJZMq9XSQQXAKgn2WugCNPj+qB+EK NOkyT5oGg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kYWpJ-0006WQ-6i; Fri, 30 Oct 2020 16:00:29 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kYWp4-0006Q1-Jx for linux-arm-kernel@lists.infradead.org; Fri, 30 Oct 2020 16:00:21 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id C38911435; Fri, 30 Oct 2020 09:00:13 -0700 (PDT) Received: from C02TD0UTHF1T.local (unknown [10.57.53.28]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E2B453F719; Fri, 30 Oct 2020 09:00:06 -0700 (PDT) Date: Fri, 30 Oct 2020 16:00:04 +0000 From: Mark Rutland To: Jann Horn Subject: Re: [PATCH v6 3/9] arm64, kfence: enable KFENCE for ARM64 Message-ID: <20201030160004.GE50718@C02TD0UTHF1T.local> References: <20201029131649.182037-1-elver@google.com> <20201029131649.182037-4-elver@google.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201030_120014_992921_747CC6A3 X-CRM114-Status: GOOD ( 17.08 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Hillf Danton , "open list:DOCUMENTATION" , Peter Zijlstra , Catalin Marinas , Dave Hansen , Linux-MM , Eric Dumazet , Alexander Potapenko , "H . Peter Anvin" , Christoph Lameter , Will Deacon , SeongJae Park , Jonathan Corbet , the arch/x86 maintainers , kasan-dev , Ingo Molnar , Vlastimil Babka , David Rientjes , Andrey Ryabinin , joern@purestorage.com, Marco Elver , Kees Cook , "Paul E . McKenney" , Andrey Konovalov , Borislav Petkov , Andy Lutomirski , Jonathan Cameron , Thomas Gleixner , Joonsoo Kim , Dmitry Vyukov , Linux ARM , Greg Kroah-Hartman , kernel list , Pekka Enberg , Andrew Morton Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Oct 30, 2020 at 03:49:26AM +0100, Jann Horn wrote: > On Thu, Oct 29, 2020 at 2:17 PM Marco Elver wrote: > > @@ -312,6 +313,9 @@ static void __do_kernel_fault(unsigned long addr, unsigned int esr, > > "Ignoring spurious kernel translation fault at virtual address %016lx\n", addr)) > > return; > > > > + if (kfence_handle_page_fault(addr)) > > + return; > > As in the X86 case, we may want to ensure that this doesn't run for > permission faults, only for non-present pages. Maybe move this down > into the third branch of the "if" block below (neither permission > fault nor NULL deref)? I think that'd make sense. Those cases *should* be mutually exclusive, but it'd be more robust to do the KFENCE checks in that last block so that if something goes wrong wrong within KFENCE we can't get stuck in a loop failing to service an instruction abort or similar. Either that, or factor out an is_el1_translation_fault() and only do the KFENCE check and is_spurious_el1_translation_fault() check under that. Thanks, Mark. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel