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=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 B457AC432BE for ; Mon, 30 Aug 2021 07:49:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8BC7060FF2 for ; Mon, 30 Aug 2021 07:49:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234030AbhH3HuG (ORCPT ); Mon, 30 Aug 2021 03:50:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40262 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233318AbhH3HuE (ORCPT ); Mon, 30 Aug 2021 03:50:04 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A35B4C061575 for ; Mon, 30 Aug 2021 00:49:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Transfer-Encoding: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=wA/gsUCb3PAoH4z1d3dqqDuu/3zM/xx6tIByC/CvD7s=; b=XcdoPMZy/0Fg3gM8QRg8zSs1qw f1WKz4JRPEXfas0+4i6K0UfdGnTpbYzU2Qep90nJauSrulL92kcHzLtCxm7ld9gUuAinQFgSsQPva 61aQp/gYxcqmVwXE54qgjJtlYTHfFFQOM/wrrV2yrWmbOe6i29RT2wmcMW9OrYpndKBJU8D9wLtI+ aT9QAICLaI7CRELUaYj3eyGctYk3nX8Bv10O/5e0j968I7hVpVsZp4G9fnERb3FsIZtpYqhfT/dN6 /l1laEWM+6h4RIWzWyJ5XAVIMRpuWmeXaLsVKO1NAQ3rKeMWj/ebsr9Jyo+DZg+EV00dJCAxSijBC lpdaB8VQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=worktop.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1mKc20-00ELyC-MN; Mon, 30 Aug 2021 07:48:36 +0000 Received: by worktop.programming.kicks-ass.net (Postfix, from userid 1000) id B8EF6981255; Mon, 30 Aug 2021 09:48:34 +0200 (CEST) Date: Mon, 30 Aug 2021 09:48:34 +0200 From: Peter Zijlstra To: Juergen Gross Cc: Josh Poimboeuf , tglx@linutronix.de, linux-kernel@vger.kernel.org, joro@8bytes.org, boris.ostrovsky@oracle.com, x86@kernel.org, mbenes@suse.com, rostedt@goodmis.org, dvyukov@google.com, elver@google.com Subject: Re: [PATCH v2 01/24] x86/xen: Mark cpu_bringup_and_idle() as dead_end_function Message-ID: <20210830074834.GE4353@worktop.programming.kicks-ass.net> References: <20210624094059.886075998@infradead.org> <20210624095147.693801717@infradead.org> <20210820192224.ytrr6ybuuwegbeov@treble> <20210820193107.omvshmsqbpxufzkc@treble> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 30, 2021 at 07:55:02AM +0200, Juergen Gross wrote: > > > From: Josh Poimboeuf > > > Subject: [PATCH] x86/xen: Move hypercall_page to top of the file > > >=20 > > > Because hypercall_page is page-aligned, the assembler inexplicably ad= ds > > > an unreachable jump from after the end of the previous code to the > > > beginning of hypercall_page. > > >=20 > > > That confuses objtool, understandably.=A0 It also creates significant= text > > > fragmentation.=A0 As a result, much of the object file is wasted text > > > (nops). > > >=20 > > > Move hypercall_page to the beginning of the file to both prevent the > > > text fragmentation and avoid the dead jump instruction. > > >=20 > > > $ size /tmp/head_64.before.o /tmp/head_64.after.o > > > =A0=A0=A0 text=A0=A0=A0=A0=A0=A0 data=A0=A0=A0=A0=A0=A0=A0 bss=A0=A0= =A0=A0=A0=A0=A0 dec=A0=A0=A0=A0=A0=A0=A0 hex=A0=A0=A0 filename > > > =A0=A0 10924=A0=A0=A0=A0 307252=A0=A0=A0=A0=A0=A0 4096=A0=A0=A0=A0 32= 2272=A0=A0=A0=A0=A0 4eae0 > > > /tmp/head_64.before.o > > > =A0=A0=A0 6823=A0=A0=A0=A0 307252=A0=A0=A0=A0=A0=A0 4096=A0=A0=A0=A0 = 318171=A0=A0=A0=A0=A0 4dadb > > > /tmp/head_64.after.o > > >=20 > > > Signed-off-by: Josh Poimboeuf >=20 > > Reviewed-by: Juergen Gross >=20 > Umm, will this be carried through the tip tree, or shall I take it in > the xen tree? I have it in the whole x86/objtool/paravirt series. I you want it in the Xen tree, I'll be happy to drop it from there, although I hope to get all that merged this cycles somewhere.