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=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,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 0F6C8C43381 for ; Mon, 18 Mar 2019 17:51:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C8FAC2084F for ; Mon, 18 Mar 2019 17:51:51 +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="UIp9E68l" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727465AbfCRRvt (ORCPT ); Mon, 18 Mar 2019 13:51:49 -0400 Received: from merlin.infradead.org ([205.233.59.134]:60934 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726626AbfCRRvs (ORCPT ); Mon, 18 Mar 2019 13:51:48 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.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=DTyWIIlYkucxzG/SiSGlpQv/dozAXvEV/aQ29qomeLE=; b=UIp9E68lC/OQGSuHAA/JMbRNc P9vh7roELswq/yfekrHuJlr2EaHl+Ayr8cNWjzy781s40pjdqt4DAlajMUnSqWnlP1TblKfJ6dC4Z OrQNKVfIMDlNOoKRcBuQDhXzJSPJR53Ti4TIy2xwjKYMn9DYZujchkpfIzUvzew9d3r07X8EFD8Ly pNm6DaGVaR/kUiwLkmU1ctorlDfV4Zo7JSoal0jraBt6/qa/+o//9jgNtxDgvLA2rG+TMmI83MlXB BN7wLURNItrG5R/JLZq5Yr5YONJhBUAn9U13RkFe39QAyOLR+ApmqCbws3YZjx/4bQXQcEtojl2nn p3Iq+96cg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1h5wQC-0007Cl-Jc; Mon, 18 Mar 2019 17:51:37 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 5D397202194EA; Mon, 18 Mar 2019 18:51:35 +0100 (CET) Date: Mon, 18 Mar 2019 18:51:35 +0100 From: Peter Zijlstra To: Linus Torvalds Cc: Thomas Gleixner , Peter Anvin , Julien Thierry , Will Deacon , Andy Lutomirski , Ingo Molnar , Catalin Marinas , James Morse , valentin.schneider@arm.com, Brian Gerst , Josh Poimboeuf , Andrew Lutomirski , Borislav Petkov , Denys Vlasenko , Linux List Kernel Mailing , Dmitry Vyukov , Steven Rostedt Subject: Re: [PATCH 01/25] x86: Make SMAP 64-bit only Message-ID: <20190318175135.GE6521@hirez.programming.kicks-ass.net> References: <20190318153840.906404905@infradead.org> <20190318155139.963285969@infradead.org> <20190318173657.GV6058@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190318173657.GV6058@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 18, 2019 at 06:36:57PM +0100, Peter Zijlstra wrote: > then I'd sleep much better if we make 32bit context switch EFLAGS. > Because, yes, x86_64 objtool validates a lot of the x86_32 code too, but > unless we have 100% coverage, there's always the chance an AC=1 escapes. How about I do a patch that schedules EFLAGS for both 32bit and 64bit, mark this for backporting to infinity. And then at the end, after the objtool-ac bits land, I do a patch removing the EFLAGS scheduling for x86_64.