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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 E3C1AC433E0 for ; Sat, 20 Feb 2021 22:33:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A395764EB2 for ; Sat, 20 Feb 2021 22:33:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229866AbhBTWdL (ORCPT ); Sat, 20 Feb 2021 17:33:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57248 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229675AbhBTWdJ (ORCPT ); Sat, 20 Feb 2021 17:33:09 -0500 Received: from merlin.infradead.org (merlin.infradead.org [IPv6:2001:8b0:10b:1231::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6DE5BC061574 for ; Sat, 20 Feb 2021 14:32:29 -0800 (PST) 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=HMTI1GJYGD0GJRodu4+13cndPWkJlvKX4R4GkQYGjaw=; b=uq7APCrAhHeXdpKZ2TAgEC0VzG a+dMX/XgXT/muyHioBjKB4J5wJyxP5eoH4tNyX0FIEGAS+5xJaeRNac7UGh5I4KMWq3aIMnpveTYh KyzouLvJg7ekNWw0/VnM39eL4oqhAzyYErDy1NPEFlAHtTI+1rPCSPxA7fB5Jm5c1N3yN2dDdzkE0 S03DOwO3YpfnddI7NxaOPZ2HI3F5ttZSxJzGLYAqJgm7ozSGUg6w2XeWmdtcBeeZK+Mmc9jlrfXzD QCq+hVCSdGEHMTH8mAoOscOUKxnPhpgbz9T2SKiaUgyvdy2ucROEkUkflzo45rdmJhKfy7gIVvQMo 3QIEh3Zw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=worktop.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1lDanX-0002Cx-9Z; Sat, 20 Feb 2021 22:32:23 +0000 Received: by worktop.programming.kicks-ass.net (Postfix, from userid 1000) id 6A25F9864D6; Sat, 20 Feb 2021 23:32:21 +0100 (CET) Date: Sat, 20 Feb 2021 23:32:21 +0100 From: Peter Zijlstra To: Borislav Petkov Cc: Josh Poimboeuf , x86@kernel.org, pjt@google.com, mbenes@suze.cz, jgross@suse.com, linux-kernel@vger.kernel.org Subject: Re: [RFC][PATCH 6/6] objtool,x86: Rewrite retpoline thunk calls Message-ID: <20210220223221.GB4746@worktop.programming.kicks-ass.net> References: <20210219204300.749932493@infradead.org> <20210219210535.492733466@infradead.org> <20210219215530.ivzzv3oavhuip6un@treble> <20210219220158.GD59023@worktop.programming.kicks-ass.net> <20210220003920.GG26778@zn.tnic> <20210220174101.GA29905@zn.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210220174101.GA29905@zn.tnic> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Feb 20, 2021 at 06:41:01PM +0100, Borislav Petkov wrote: > > - if we had negative alternatives objtool doesn't need to actually > > rewrite code in this case. It could simply emit alternative entries > > and call it a day. > > I don't mind the negative alt per se - I mind the implementation I saw. > I'm sure we can come up with something nicer, like, for example, struct > alt_instr.flags to denote that this feature is a NOT feature. So you don't like the ~ or - on cpuid? ISTR we talked about alt_instr::flags before, but Google isn't playing ball today so I can't seem to find it. I can certainly look at adding the flags thing.