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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 5BEA7C43331 for ; Fri, 3 Apr 2020 18:20:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1FA87206CC for ; Fri, 3 Apr 2020 18:20:16 +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="kaDOvEDt" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728483AbgDCSUP (ORCPT ); Fri, 3 Apr 2020 14:20:15 -0400 Received: from merlin.infradead.org ([205.233.59.134]:56482 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728268AbgDCSUO (ORCPT ); Fri, 3 Apr 2020 14:20:14 -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; bh=2dKDGpqijVtdLIYlA6wF/IukuIi+37yb9HKFfYMStlk=; b=kaDOvEDtAAkWAJWmPA6o4gjBww 6Vk4be/+t5ebFQlnfvZHv2zf6EcgEIRlBVTltimFDRQdrzQQ1YCEi7ZnXNghZWK9yJJq5OCJlCNn7 JyeeZ2x11KE8QP1kNrkqpH1WIF2HAFaS3OsSq3cru48n+F8YKcKWIa5b6zLcZ9ulK0IjgH/Mt0F4R i/om2K+qIV+cXchQ+TGsGjMNtvRaoqiU0PkaHQOhyBUuD00lToTZwNBCZKbWcVuLeB6A+JvmXKwSN CxFzfStAYzYj3yVGgG2EQFTa3V5x0cSWiPMCrujwN2v9IiuD8WtQuHVHhvbIMg1qXdGw6fYt/xfwx CUtOJKEA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jKQvI-000502-2I; Fri, 03 Apr 2020 18:20:08 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 88E5C3056DE; Fri, 3 Apr 2020 20:20:05 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 6F8A82B1255EA; Fri, 3 Apr 2020 20:20:05 +0200 (CEST) Date: Fri, 3 Apr 2020 20:20:05 +0200 From: Peter Zijlstra To: Josh Poimboeuf Cc: Alexandre Chartre , x86@kernel.org, linux-kernel@vger.kernel.org, jthierry@redhat.com, tglx@linutronix.de Subject: Re: [PATCH 5/7] x86/speculation: Annotate intra-function calls Message-ID: <20200403182005.GC20730@hirez.programming.kicks-ass.net> References: <20200402082220.808-1-alexandre.chartre@oracle.com> <20200402082220.808-6-alexandre.chartre@oracle.com> <20200403160538.qwu237amhanr6pyi@treble> <20200403161607.jxz6duaz7dud22wf@treble> <2c615bae-6002-80b7-493d-b24ec48f69c9@oracle.com> <20200403171836.GB20730@hirez.programming.kicks-ass.net> <20200403172408.odvcsymwlyx6ises@treble> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200403172408.odvcsymwlyx6ises@treble> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 03, 2020 at 12:24:08PM -0500, Josh Poimboeuf wrote: > On Fri, Apr 03, 2020 at 07:18:36PM +0200, Peter Zijlstra wrote: > > What we need in this case though is only a different stack layout inside > > the alternative, and that is doable. > > I'm not sure what you mean... any stack changes within the alternative > have to match exactly the stack changes at the same offsets of the > original code because ORC doesn't know the difference between the two. I mean that the ORC entries on either side of the alternative have to be invariant wrt the specific alternative chosen, but that -- provded you whip up that ORC alternative stuff -- stack layout inside of an alternative could possibly be different.