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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 78471E77188 for ; Sun, 12 Jan 2025 11:56:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=PLIBK3rk4FZvefXRrp/h66V6u/1v8yJK25LGqINfgME=; b=jJUzt6oqaFkOdxTqBQTWUB6/uQ c3muTs61NxEjgWQ92iqKXf1qn+pwBm31CaGCJ3OXPyGS2UeJ0QY61DvZ2YeQCrrgcOELnvGOVAV1I S5EgdPF2NNjmMKkWJvBG/JS6/QS2v4ntTxgDs4eEu24qVFKenK7jTS5l4fcPiCodULuXeC8daVEo4 PhzHBSe5/ynrBHLK9+0vLLLV6/gqk6l5B1mvrMB4tIMsAA4kfaFq4eT6D7q8D/2fdN17hLWMSOoCx 9YHkM1mlR8m6y6ZV2/2BibNtcECNE8vfNimZfAOBBubgmGjR6aR1Q8OR9agXIlfEnmJ8Lyv0MTX04 uUTvOgHw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tWwZm-00000002cdV-3s1A; Sun, 12 Jan 2025 11:56:18 +0000 Received: from dfw.source.kernel.org ([139.178.84.217]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tWwXf-00000002cKQ-0gDh for linux-arm-kernel@lists.infradead.org; Sun, 12 Jan 2025 11:54:08 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id AD34E5C3A7B; Sun, 12 Jan 2025 11:53:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A13B8C4CEDF; Sun, 12 Jan 2025 11:54:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1736682846; bh=k9CUYWfksPToLLELTTvrBkhNkzM6VlpA7t8yoRYCU6Y=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=X10MBEIyhoPuClKxHrwevxo6PbuR0AuZt/CWbNasgn/OF+CGu716enYtbB1AadHPR n84wL4ThACtPdQNsMH66UqqS1WWRpKesoaiiGZ78N9i0TYoml3H5NveXSJaDH+d8xp dBeRJKE/iI38ZeNfWZZ07y6F+PxZgiQUdgrlMMI0= Date: Sun, 12 Jan 2025 12:54:03 +0100 From: Greg KH To: Florian Fainelli Cc: stable@vger.kernel.org, Ard Biesheuvel , Anshuman Khandual , Will Deacon , Steven Price , Robin Murphy , Catalin Marinas , Baruch Siach , Petr Tesarik , Mark Rutland , Joey Gouly , "Mike Rapoport (IBM)" , Yang Shi , "moderated list:ARM64 PORT (AARCH64 ARCHITECTURE)" , open list Subject: Re: [PATCH] arm64: mm: account for hotplug memory when randomizing the linear region Message-ID: <2025011247-enable-freezing-ffa2@gregkh> References: <20250109165419.1623683-1-florian.fainelli@broadcom.com> <20250109165419.1623683-2-florian.fainelli@broadcom.com> <62786457-d4a1-4861-8bec-7e478626f4db@broadcom.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <62786457-d4a1-4861-8bec-7e478626f4db@broadcom.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250112_035407_258358_55D6889B X-CRM114-Status: GOOD ( 19.99 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Jan 09, 2025 at 09:01:13AM -0800, Florian Fainelli wrote: > On 1/9/25 08:54, Florian Fainelli wrote: > > From: Ard Biesheuvel > > > > commit 97d6786e0669daa5c2f2d07a057f574e849dfd3e upstream > > > > 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. > > > > So let's limit this randomization of the linear region to ensure > > that this can no longer happen, by using the CPU's addressable PA > > range instead. As it is guaranteed that no hotpluggable memory will > > appear that falls outside of that range, we can safely put this PA > > range sized window anywhere in the linear region. > > > > Signed-off-by: Ard Biesheuvel > > Cc: Anshuman Khandual > > Cc: Will Deacon > > Cc: Steven Price > > Cc: Robin Murphy > > Link: https://lore.kernel.org/r/20201014081857.3288-1-ardb@kernel.org > > Signed-off-by: Catalin Marinas > > Signed-off-by: Florian Fainelli > > Forgot to update the patch subject, but this one is for 5.10. You also forgot to tell us _why_ this is needed :( thanks, greg k-h