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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 5A7E0C2D0E4 for ; Fri, 13 Nov 2020 03:17:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0717A20A8B for ; Fri, 13 Nov 2020 03:17:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726276AbgKMDQm (ORCPT ); Thu, 12 Nov 2020 22:16:42 -0500 Received: from foss.arm.com ([217.140.110.172]:60274 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725965AbgKMDQm (ORCPT ); Thu, 12 Nov 2020 22:16:42 -0500 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 75BF51042; Thu, 12 Nov 2020 19:16:41 -0800 (PST) Received: from [10.163.79.120] (unknown [10.163.79.120]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0542F3F6CF; Thu, 12 Nov 2020 19:16:35 -0800 (PST) Subject: Re: [PATCH] arm64: mm: account for hotplug memory when randomizing the linear region To: Catalin Marinas Cc: linux-arm-kernel@lists.infradead.org, Ard Biesheuvel , Will Deacon , linux-kernel@vger.kernel.org, Mark Rutland , Steve Capper , Mark Brown , Marc Zyngier , gshan@redhat.com, Robin Murphy , Steven Price , David Hildenbrand References: <20201014081857.3288-1-ardb@kernel.org> <160503561804.1015659.16599672230432576934.b4-ty@arm.com> <20201112092558.GC29613@gaia> From: Anshuman Khandual Message-ID: <2f0d9bc5-6288-7388-ff10-97198dabac6f@arm.com> Date: Fri, 13 Nov 2020 08:46:27 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20201112092558.GC29613@gaia> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/12/20 2:55 PM, Catalin Marinas wrote: > Hi Anshuman, > > On Wed, Nov 11, 2020 at 09:18:56AM +0530, Anshuman Khandual wrote: >> On 11/11/20 12:44 AM, Catalin Marinas wrote: >>> On Wed, 14 Oct 2020 10:18:57 +0200, Ard Biesheuvel wrote: >>>> As a hardening measure, we currently randomize the placement of >>>> physical memory inside the linear region when KASLR is in effect. >>>> Since the random offset at which to place the available physical >>>> memory inside the linear region is chosen early at boot, it is >>>> based on the memblock description of memory, which does not cover >>>> hotplug memory. The consequence of this is that the randomization >>>> offset may be chosen such that any hotplugged memory located above >>>> memblock_end_of_DRAM() that appears later is pushed off the end of >>>> the linear region, where it cannot be accessed. >>>> >>>> [...] >>> >>> Applied to arm64 (for-next/mem-hotplug), thanks! >>> >>> [1/1] arm64: mm: account for hotplug memory when randomizing the linear region >>> https://git.kernel.org/arm64/c/97d6786e0669 >> >> Got delayed and never made here in time, sorry about that. Nonetheless, >> I have got something working with respect to the generic mechanism that >> David Hildenbrand had asked for earlier. >> >> https://patchwork.kernel.org/project/linux-arm-kernel/patch/1600332402-30123-1-git-send-email-anshuman.khandual@arm.com/ > > There was a lot of discussion around this patch but I haven't seen any > new version posted. Just posted before some time. https://lore.kernel.org/linux-arm-kernel/1605236574-14636-1-git-send-email-anshuman.khandual@arm.com/ > >> I am wondering if we could instead consider merging the above patch with >> a small change that Ard had pointed out earlier [1], I will send out a >> revision if required. > > If your patch fixes the randomisation issue that Ard addressed, I'm > happy to replace that with your patch. But please post a new version and > get some acks in place from the parties involved in the discussion. The above patch is not a replacement for Ard's randomization patch here but rather complements it. Hence both these patches should be considered, which will make memory hotplug better on the platform. 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=-10.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,NICE_REPLY_A,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 33281C2D0E4 for ; Fri, 13 Nov 2020 03:17:20 +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 A07D120A8B for ; Fri, 13 Nov 2020 03:17:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="R/LGwtjr" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A07D120A8B 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: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=WP4CKdg9P/GChb8u3I2OSstftpv7maJ2UVo5l+9FdS0=; b=R/LGwtjrhQ3HNULHiBKYaDUYs jOWbrJ6aRYTBilTrpZgjRiA0IIyDf6ZMJ05RfWXAi7GxCVf/+HrDzX2h7i1xb9GdvxXQTaRxQl6H0 7YI3yCh+aDUWElaFM+WwntbC4FaOdHC6cQMUDc6JrhFW1QAHRSyJX0XngNFe24dfZvOIu5yyiofEb fCIe2qW3P3gr73gKvOoSCmX5xm137D1dBrMPZfcnZm+x6ZAALFOKLVXjvRp/KrIM5CMUtdkonkVzD QqQfcz5ssRV90Rfpci6lBjQ10YD5bBM3Ix6exENvSE4PZ/ud46roueJLXetPN9k+zAYp0LRZ3FX+o hLVFsfaMw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kdPZw-0007F5-18; Fri, 13 Nov 2020 03:16:48 +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 1kdPZs-0007Eg-KS for linux-arm-kernel@lists.infradead.org; Fri, 13 Nov 2020 03:16:45 +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 75BF51042; Thu, 12 Nov 2020 19:16:41 -0800 (PST) Received: from [10.163.79.120] (unknown [10.163.79.120]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0542F3F6CF; Thu, 12 Nov 2020 19:16:35 -0800 (PST) Subject: Re: [PATCH] arm64: mm: account for hotplug memory when randomizing the linear region To: Catalin Marinas References: <20201014081857.3288-1-ardb@kernel.org> <160503561804.1015659.16599672230432576934.b4-ty@arm.com> <20201112092558.GC29613@gaia> From: Anshuman Khandual Message-ID: <2f0d9bc5-6288-7388-ff10-97198dabac6f@arm.com> Date: Fri, 13 Nov 2020 08:46:27 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20201112092558.GC29613@gaia> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201112_221644_818520_98006614 X-CRM114-Status: GOOD ( 22.43 ) 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: Mark Rutland , gshan@redhat.com, Steve Capper , Marc Zyngier , David Hildenbrand , linux-kernel@vger.kernel.org, Steven Price , Mark Brown , Will Deacon , Ard Biesheuvel , linux-arm-kernel@lists.infradead.org, Robin Murphy 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 11/12/20 2:55 PM, Catalin Marinas wrote: > Hi Anshuman, > > On Wed, Nov 11, 2020 at 09:18:56AM +0530, Anshuman Khandual wrote: >> On 11/11/20 12:44 AM, Catalin Marinas wrote: >>> On Wed, 14 Oct 2020 10:18:57 +0200, Ard Biesheuvel wrote: >>>> As a hardening measure, we currently randomize the placement of >>>> physical memory inside the linear region when KASLR is in effect. >>>> Since the random offset at which to place the available physical >>>> memory inside the linear region is chosen early at boot, it is >>>> based on the memblock description of memory, which does not cover >>>> hotplug memory. The consequence of this is that the randomization >>>> offset may be chosen such that any hotplugged memory located above >>>> memblock_end_of_DRAM() that appears later is pushed off the end of >>>> the linear region, where it cannot be accessed. >>>> >>>> [...] >>> >>> Applied to arm64 (for-next/mem-hotplug), thanks! >>> >>> [1/1] arm64: mm: account for hotplug memory when randomizing the linear region >>> https://git.kernel.org/arm64/c/97d6786e0669 >> >> Got delayed and never made here in time, sorry about that. Nonetheless, >> I have got something working with respect to the generic mechanism that >> David Hildenbrand had asked for earlier. >> >> https://patchwork.kernel.org/project/linux-arm-kernel/patch/1600332402-30123-1-git-send-email-anshuman.khandual@arm.com/ > > There was a lot of discussion around this patch but I haven't seen any > new version posted. Just posted before some time. https://lore.kernel.org/linux-arm-kernel/1605236574-14636-1-git-send-email-anshuman.khandual@arm.com/ > >> I am wondering if we could instead consider merging the above patch with >> a small change that Ard had pointed out earlier [1], I will send out a >> revision if required. > > If your patch fixes the randomisation issue that Ard addressed, I'm > happy to replace that with your patch. But please post a new version and > get some acks in place from the parties involved in the discussion. The above patch is not a replacement for Ard's randomization patch here but rather complements it. Hence both these patches should be considered, which will make memory hotplug better on the platform. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel