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=-10.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,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 B5BE4C2D0A3 for ; Thu, 12 Nov 2020 09:26:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5907E221FF for ; Thu, 12 Nov 2020 09:26:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727291AbgKLJ0F (ORCPT ); Thu, 12 Nov 2020 04:26:05 -0500 Received: from mail.kernel.org ([198.145.29.99]:36566 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726028AbgKLJ0F (ORCPT ); Thu, 12 Nov 2020 04:26:05 -0500 Received: from gaia (unknown [2.26.170.190]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 180BF221FE; Thu, 12 Nov 2020 09:26:00 +0000 (UTC) Date: Thu, 12 Nov 2020 09:25:58 +0000 From: Catalin Marinas To: Anshuman Khandual 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 Subject: Re: [PATCH] arm64: mm: account for hotplug memory when randomizing the linear region Message-ID: <20201112092558.GC29613@gaia> References: <20201014081857.3288-1-ardb@kernel.org> <160503561804.1015659.16599672230432576934.b4-ty@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. > 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. Thanks. -- Catalin