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=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 3EC7AC388F7 for ; Fri, 13 Nov 2020 07:40:42 +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 9B55120936 for ; Fri, 13 Nov 2020 07:40:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="pLmfseDq" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9B55120936 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=/YKlby+daBHnaFyi1Vy3fRlPjA885E3rP1e+6+xzWQw=; b=pLmfseDqQiXDyBMRM//HRd2oM q0iEKSJQ6DqZAmaulU0CcD/Q4MpnL465kjAJgewMlRLoqdmot4JymQ7rYBLj0bt4UDJzAQakQM7/4 KdWnYE3j1cS7wOu+/QlDTPaTLL25Fh2afy0WaL1W4XRNB9kPTngdQExnH0W6X3l1MBaTLVrf/PG9r oQVlzlquGWONkc3waRa8HvIQVsBSqdSgyxEir7dgVTubbBTQEe4/k5z3sx2Mvqzbm7nJQb1gMC7n1 veBNP5yuqiN6k5Hracohxs6jHxNaFItlZmyqa5ULFMJ1TQakYOizgldZ+iYyOztpGRYhmtuqYTgIt t9okB/Udg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kdTgs-0006TK-EQ; Fri, 13 Nov 2020 07:40:14 +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 1kdTgp-0006SU-2J for linux-arm-kernel@lists.infradead.org; Fri, 13 Nov 2020 07:40:12 +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 E02A2142F; Thu, 12 Nov 2020 23:40:09 -0800 (PST) Received: from [10.163.80.57] (unknown [10.163.80.57]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id BB8013F718; Thu, 12 Nov 2020 23:40:04 -0800 (PST) Subject: Re: [PATCH] arm64: mm: account for hotplug memory when randomizing the linear region To: Ard Biesheuvel References: <20201014081857.3288-1-ardb@kernel.org> <160503561804.1015659.16599672230432576934.b4-ty@arm.com> <20201112092558.GC29613@gaia> <2f0d9bc5-6288-7388-ff10-97198dabac6f@arm.com> From: Anshuman Khandual Message-ID: <2e84fa4b-f35b-5ecf-5b67-f570bdd29a06@arm.com> Date: Fri, 13 Nov 2020 13:10:01 +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: Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201113_024011_211382_70325476 X-CRM114-Status: GOOD ( 27.82 ) 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 , Catalin Marinas , David Hildenbrand , Linux Kernel Mailing List , Steven Price , Mark Brown , Marc Zyngier , Will Deacon , Linux ARM , 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 11/13/20 12:36 PM, Ard Biesheuvel wrote: > On Fri, 13 Nov 2020 at 08:03, Anshuman Khandual > wrote: >> >> >> >> On 11/13/20 11:44 AM, Ard Biesheuvel wrote: >>> On Fri, 13 Nov 2020 at 04:16, Anshuman Khandual >>> wrote: >>>> >>>> >>>> >>>> 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/ >>>> >>> >>> You failed to cc me on that patch. >> >> I could see 'ardb@kernel.org' marked as a copy on the patch. You >> did not receive the email ? The CC list is in the commit message >> itself. Even the lore.kernel.org based URL does list you email >> as well. Not sure what might have happened. >> >> Cc: Catalin Marinas >> Cc: Will Deacon >> Cc: Mark Rutland >> Cc: Ard Biesheuvel >> Cc: Steven Price >> Cc: Robin Murphy >> Cc: David Hildenbrand >> Cc: Andrew Morton >> Cc: linux-arm-kernel@lists.infradead.org >> Cc: linux-kernel@vger.kernel.org >> > > Right. Not sure what happened there, I may have deleted it by > accident. Apologies. > >>> >>> The logic looks correct but please fix up the comment block: >>> - PAGE_END is no longer defined in terms of vabits_actual >>> - bits [51..48] are not ignored by the MMU >>> >>> Actually, I think the entire second paragraph of that comment block >>> can be dropped. >> >> And from the commit message as well, had reused it in both places. >> >>> >>> Please also fix up the coding style: >>> - put && at the end of the first line >>> - drop the redundant parens >>> - fix the indentation >> >> Does this look okay ? >> >> static bool inside_linear_region(u64 start, u64 size) >> { >> /* >> * Linear mapping region is the range [PAGE_OFFSET..(PAGE_END - 1)] >> * accommodating both its ends but excluding PAGE_END. Max physical >> * range which can be mapped inside this linear mapping range, must >> * also be derived from its end points. >> */ >> return start >= __pa(_PAGE_OFFSET(vabits_actual)) && >> (start + size - 1) <= __pa(PAGE_END - 1); >> } > > Not sure whether the whitespace has been mangled by the email client, > but the first ( on the second line should align vertically with the > 's' of 'start' on the first line It was not aligned vertically here but fixed it. I hope you have received the latest version this time. https://lore.kernel.org/linux-arm-kernel/1605252614-761-1-git-send-email-anshuman.khandual@arm.com/ _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel