From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x226hyJB+j51W/oMaSlmqqft0TewgxgTmWEgXtiJUzEB/yiiY13sofmOOs+r05nzT7QVdhTyK ARC-Seal: i=1; a=rsa-sha256; t=1518646429; cv=none; d=google.com; s=arc-20160816; b=fccrpAxg8MBZcpcUfiFmnCFX2B/geCX7joxR8yZNeSFhMzQq4Aq9SYnlPU1TT23B3W dK/Tr2e8BADkW+r4yCO280ep7so9nFyFVfk4GLAxi9TeLhngROS6HXpWX0k7ky7D1T0g 6ftddsPZSt0OcaHvAl062HIsh5BAFycrccq2mJiFu2eaU0v0QKXJ4D2ml9S9vbsqdPiQ UUBV1RkirKBr5vqjdg8eSD6uzV/7caPrPSSc/36N8kqvh8ncMyMRf/xua2TAdz4axX7u RalxiTOmdx9vdiPOwZ9EtbT/F+no+CNk816WHzC9lf19Veg1DUB9q8kDzhmgiYRHx9V9 OYgA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date:dkim-signature:delivered-to :list-id:list-subscribe:list-unsubscribe:list-help:list-post :precedence:mailing-list:arc-authentication-results; bh=1I5emYBdMczpmvIvlKtYj1XMEMflhndJ0aLrBKYk+N8=; b=S1v+0EPs7oUbJCbmIf1GGbF8CCn84dj9jxNQXu/sqoTVvG4mXg5Pi3rf+ZitzqzM4l SXzYKfRigNuJ2AXaBIxJRApnDVqpNlWnT9E44z4ovdIjQ35l8qa5KqZWhKj9+UWX/RRN zLZD/cG+BxFBdBWFgY6LEMa4qHmvDSvchRMoxHyLDO9OZyY+rqQpyBxSQchToQNZED/u EGQn1nLJSe8VQWZhMjPzAwvnmR4L7aY6swnrkLBYgeY0YyHZrSj7GaloWTWTdyUG5i3M dAWLfgHRL2/mR5yruVyQEeEP2lF7zpE+22jb7J/oJs3u2dUsr2a7Yz6LpG9PRnVtGfpo izJQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@tycho-ws.20150623.gappssmtp.com header.s=20150623 header.b=BVh2o/MN; spf=pass (google.com: domain of kernel-hardening-return-11795-gregkh=linuxfoundation.org@lists.openwall.com designates 195.42.179.200 as permitted sender) smtp.mailfrom=kernel-hardening-return-11795-gregkh=linuxfoundation.org@lists.openwall.com Authentication-Results: mx.google.com; dkim=pass header.i=@tycho-ws.20150623.gappssmtp.com header.s=20150623 header.b=BVh2o/MN; spf=pass (google.com: domain of kernel-hardening-return-11795-gregkh=linuxfoundation.org@lists.openwall.com designates 195.42.179.200 as permitted sender) smtp.mailfrom=kernel-hardening-return-11795-gregkh=linuxfoundation.org@lists.openwall.com Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm List-Post: List-Help: List-Unsubscribe: List-Subscribe: Date: Wed, 14 Feb 2018 15:13:28 -0700 From: Tycho Andersen To: Kees Cook Cc: Laura Abbott , Jann Horn , Igor Stoppa , Boris Lukashev , Christopher Lameter , Matthew Wilcox , Jerome Glisse , Michal Hocko , Christoph Hellwig , linux-security-module , Linux-MM , kernel list , Kernel Hardening , linux-arm-kernel Subject: Re: arm64 physmap (was Re: [kernel-hardening] [PATCH 4/6] Protectable Memory) Message-ID: <20180214221328.glbrdib3wumve53z@cisco> References: <17e5b515-84c8-dca2-1695-cdf819834ea2@huawei.com> <414027d3-dd73-cf11-dc2a-e8c124591646@redhat.com> <2f23544a-bd24-1e71-967b-e8d1cf5a20a3@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170609 (1.8.3) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1592404410626838547?= X-GMAIL-MSGID: =?utf-8?q?1592416198825543505?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Wed, Feb 14, 2018 at 11:48:38AM -0800, Kees Cook wrote: > On Wed, Feb 14, 2018 at 11:06 AM, Laura Abbott wrote: > > fixed. Modules yes are not fully protected. The conclusion from past > > experience has been that we cannot safely break down larger page sizes > > at runtime like x86 does. We could theoretically > > add support for fixing up the alias if PAGE_POISONING is enabled but > > I don't know who would actually use that in production. Performance > > is very poor at that point. > > XPFO forces 4K pages on the physmap[1] for similar reasons. I have no > doubt about performance changes, but I'd be curious to see real > numbers. Did anyone do benchmarks on just the huge/4K change? (Without > also the XPFO overhead?) > > If this, XPFO, and PAGE_POISONING all need it, I think we have to > start a closer investigation. :) I haven't but it shouldn't be too hard. What benchmarks are you thinking? Tycho