Received: by 2002:a25:c593:0:0:0:0:0 with SMTP id v141csp60848ybe; Wed, 18 Sep 2019 12:58:05 -0700 (PDT) X-Google-Smtp-Source: APXvYqzak7W9PgMWfZ9LWhsLIAG+hmIh25o8+wkm6GKeezCEuAPWoyf1Zsonlzc88W0WVxTlALD7 X-Received: by 2002:a50:9e08:: with SMTP id z8mr12550532ede.305.1568836685072; Wed, 18 Sep 2019 12:58:05 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1568836685; cv=none; d=google.com; s=arc-20160816; b=Z7fMjOAqykb2cj6RdQuAryj/jdwoN9MR+Gk8MCTp0cKji93IiPJMcWHSBpPCIzR1hJ ffMSJ9N7s9GgwGhEZEEon/iqoGa8OmaY13fELxnCbvyD1tzbzQhqtKpQbgy8S/qm/Zu5 D+KJzarYAE0djWzN1rlPMlr4ZT2KjvIfVKPprsvEdEpJoXg9uY+dHWt8gs61Crv3xDW8 gMwOGSYk79Ea9KUqht7ZiML7ndqpR9gaYhD1Z5rvwV4xC8EtFlN1eHrjAGO4EKU3c4qV yqV2p90wx33k1zDIpT6+OaXmstz/P7RQx035cVb6uFEh6r9x7aGwd/17Iq7mlcUafQQA L4vw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:user-agent:in-reply-to :content-disposition:mime-version:references:message-id:subject:cc :to:from:date; bh=nH1JlhOdbP9rMxPfeAVeaku1W9cigV6O2R5/32TfY94=; b=pYBqAUJocwdmL8vTZt3jbp6+qfWPORg0RAonFHCBc0YLWHh6HGbF8+1KW/eGciYchc nKnudebvM5ZnQ/W9CZSZfGPCYkumO/JNdq2xPvwtmeDkKWOPtgDJp6ElbMR+/WwVYwK8 Xlik1qvNXFF0DqBwCYac/5+P8DQWOsXHolSxQG/JPEGZngB9oAUJ1rymVm2r2m2bolNl ZLrX82jsJkVGzbp9AEBzVF2s6XxpCPm7lA60hSIz6MOgaCKyRoiMolT7K/9IJegZC0NR WlTVISdR97rTszpnSnGG6m6pM0VoaktP4CZr1ns8UCrvs6cjol8px/KEe8ICa1+dsUnm OZvA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id j14si3282338ejf.53.2019.09.18.12.57.41; Wed, 18 Sep 2019 12:58:05 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731044AbfIRQpY (ORCPT + 99 others); Wed, 18 Sep 2019 12:45:24 -0400 Received: from verein.lst.de ([213.95.11.211]:34532 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730380AbfIRQpY (ORCPT ); Wed, 18 Sep 2019 12:45:24 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id 1BC5F68B05; Wed, 18 Sep 2019 18:45:19 +0200 (CEST) Date: Wed, 18 Sep 2019 18:45:18 +0200 From: Christoph Hellwig To: Larry Finger Cc: Linus Torvalds , linux-kernel@vger.kernel.org, Christoph Hellwig , Peter Zijlstra , Ingo Molnar , Greg Kroah-Hartman Subject: Re: [PATCH] x86/mm: Remove set_pages_x() and set_pages_nx() Message-ID: <20190918164518.GA19222@lst.de> References: <20190918164121.30006-1-Larry.Finger@lwfinger.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190918164121.30006-1-Larry.Finger@lwfinger.net> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Sep 18, 2019 at 11:41:21AM -0500, Larry Finger wrote: > In commit 185be15143aa ("x86/mm: Remove set_pages_x() and set_pages_nx()"), > the wrappers were removed as they did not provide a real benefit over > set_memory_x() and set_memory_nx(). This change causes a problem because > the wrappers were exported, but the underlying routines were not. As a > result, external modules that used the wrappers would need to recreate > a significant part of memory management. And external modules do not matter for mainline decisions. In fact ensuring random modules can't mess with the NX state was one of the reasons for this patch, as that is a security issue waiting to happen.