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=-5.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 37365C3A5A1 for ; Wed, 28 Aug 2019 11:00:26 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 0B17F208CB for ; Wed, 28 Aug 2019 11:00:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="lsud5MJ2" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0B17F208CB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-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=bombadil.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:Date: Message-ID:From:References:To:Subject:Reply-To:Content-ID:Content-Description :Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=GZ6b9xnmVXYnUd2bPGxvkXVTRtzRxPCMQosvkhlxkyc=; b=lsud5MJ2fDnWIc VrlmPjPLxtzhgnbIVCw8LRpBUdQvEWw1MkAomLV4eGtRqJCYDrlVSSo391Ts2FQgigf3QGwLTeM/M d/YRbpKRR6FERzuK+dGAS0Bh2cOrZKYY3JjVQpK9t+KneDBGMHMR+AYP8Kj1GZ9D5t6C8ZSHHy+is msazNF6ldR94WKD7H+KPd/5YgzPvriV9Z0GFn5MxpaIVgmdE7hjELlAbSVPBjVRfkkOyyP5FtWTZC W+i0o7ww9+1OPOoQILUGHRIGb4fatLGhSTbZRSmb01CItZvKfii2Muqqd6m4ms4ncMarY9LMiwGdS 80+QTsqrwfjzkE3JxjMw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1i2vgf-00017q-Kb; Wed, 28 Aug 2019 11:00:25 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1i2vgd-00017N-9N for linux-arm-kernel@lists.infradead.org; Wed, 28 Aug 2019 11:00:24 +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 7024E337; Wed, 28 Aug 2019 04:00:21 -0700 (PDT) Received: from [10.162.40.83] (p8cg001049571a15.blr.arm.com [10.162.40.83]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 8A78A3F59C; Wed, 28 Aug 2019 04:00:19 -0700 (PDT) Subject: Re: [PATCH] arm64: fix fixmap copy for 16K pages and 48-bit VA To: Mark Rutland , linux-arm-kernel@lists.infradead.org References: <20190827155708.34699-1-mark.rutland@arm.com> From: Anshuman Khandual Message-ID: <013bdf63-915b-4350-b3c5-3913cf4f4b90@arm.com> Date: Wed, 28 Aug 2019 16:30:22 +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: <20190827155708.34699-1-mark.rutland@arm.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190828_040023_375368_9CB4AB59 X-CRM114-Status: GOOD ( 17.56 ) 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: Catalin Marinas , Steve Capper , Marc Zyngier , Will Deacon , Ard Biesheuvel Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 08/27/2019 09:27 PM, Mark Rutland wrote: > With 16K pages and 48-bit VAs, the PGD level of table has two entries, > and so the fixmap shares a PGD with the kernel image. Since commit: > > f9040773b7bbbd9e ("arm64: move kernel image to base of vmalloc area") > > ... we copy the existing fixmap to the new fine-grained page tables at > the PUD level in this case. When walking to the new PUD, we forgot to > offset the PGD entry and always used the PGD entry at index 0, but this > worked as the kernel image and fixmap were in the low half of the TTBR1 > address space. > > As of commit: > > 14c127c957c1c607 ("arm64: mm: Flip kernel VA space") > > ... the kernel image and fixmap are in the high half of the TTBR1 > address space, and hence use the PGD at index 1, but we didn't update > the fixmap copying code to account for this. > > Thus, we'll erroneously try to copy the fixmap slots into a PUD under > the PGD entry at index 0. At the point we do so this PGD entry has not > been initialised, and thus we'll try to write a value to a small offset > from physical address 0, causing a number of potential problems. > > Fix this be correctly offsetting the PGD. This is split over a few steps > for legibility. > > Fixes: 14c127c957c1c607 ("arm64: mm: Flip kernel VA space") > Reported-by: Anshuman Khandual > Signed-off-by: Mark Rutland > Cc: Ard Biesheuvel > Cc: Catalin Marinas > Cc: Marc Zyngier > Cc: Steve Capper > Cc: Will Deacon Tested-by: Anshuman Khandual _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel