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=-2.2 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, USER_AGENT_MUTT 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 63645C433F5 for ; Sun, 26 Aug 2018 22:16:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F1ECD216FA for ; Sun, 26 Aug 2018 22:16:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="Ug98x9Zk" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F1ECD216FA Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727023AbeH0CAE (ORCPT ); Sun, 26 Aug 2018 22:00:04 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:52068 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726831AbeH0CAD (ORCPT ); Sun, 26 Aug 2018 22:00:03 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=U1xK8R2nt5oLYf6ZDOXGtnO7yEEcsyGQ7xnTDDSx+tI=; b=Ug98x9ZkRhZg5xujjnsbiQnT8 SV5o5I+FN1NGyRL5Lk+22gyMFgImFcyAVdSjxIpSAb8bCIGN2JEMjV4Xo/iylLwNR8kdd9vFseyfr uo8K5Fpe/byxvyth8KQ5G6XCeYJfLIoNehrrPLGcdreeUl2rX2r3kgCjZkj6mP5d6+wEVgZfZMDdP CdHkgf5G8AMLuzpWVcjquOdLdhvCnOy2jw6kETnARJ6knbE0Jbo183GzYc4h/8dMSdOZteDUHg6c5 n1FnT4HpUBU4J1CfcKT5pM0UoJxBvlcrhs+4jAqOB/AwYgDAg5KkQohqkID3O7+Q4gP/u2ftW5srU A7dM3x4rA==; Received: from willy by bombadil.infradead.org with local (Exim 4.90_1 #2 (Red Hat Linux)) id 1fu3Jt-0001KP-Pg; Sun, 26 Aug 2018 22:15:41 +0000 Date: Sun, 26 Aug 2018 15:15:41 -0700 From: Matthew Wilcox To: Kees Cook Cc: Thomas Gleixner , Andy Lutomirski , Andy Lutomirski , Masami Hiramatsu , Nadav Amit , Linus Torvalds , Paolo Bonzini , Jiri Kosina , Peter Zijlstra , Will Deacon , Benjamin Herrenschmidt , Nick Piggin , the arch/x86 maintainers , Borislav Petkov , Rik van Riel , Jann Horn , Adin Scannell , Dave Hansen , Linux Kernel Mailing List , linux-mm , David Miller , Martin Schwidefsky , Michael Ellerman Subject: Re: TLB flushes on fixmap changes Message-ID: <20180826221541.GB30765@bombadil.infradead.org> References: <8E0D8C66-6F21-4890-8984-B6B3082D4CC5@gmail.com> <20180826112341.f77a528763e297cbc36058fa@kernel.org> <952A64F0-90B3-4E2F-B410-7E20BE90D617@amacapital.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Aug 26, 2018 at 03:03:59PM -0700, Kees Cook wrote: > I thought the point was that the implementation I suggested was > NMI-proof? (And in reading Documentation/preempt-locking.txt it sounds > like disabling interrupts is redundant to preempt_disable()? But I > don't understand how; it looks like the preempt stuff is advisory?) Oter way round; disabling interrupts implicitly disables preemption