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 E3014C43441 for ; Sat, 10 Nov 2018 23:21:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AA4B42089A for ; Sat, 10 Nov 2018 23:21:21 +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="vaTz9YyF" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AA4B42089A 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 S1726996AbeKKJH5 (ORCPT ); Sun, 11 Nov 2018 04:07:57 -0500 Received: from merlin.infradead.org ([205.233.59.134]:50802 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725859AbeKKJH5 (ORCPT ); Sun, 11 Nov 2018 04:07:57 -0500 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=pcvfrR2weqwFeCK+WlufDQK7hMyRibZsLKYSvbC9F3s=; b=vaTz9YyFye7cpozLKKUwPXGoS A+GoN2RKkxvysS0DXkwIlhtqGanV4dyhmvbrkvKu44/EPr6e5QFjXMVFzLbWgwviI63LMF/ax4X6Y /fFEXGa4I/td88PZ3hnExzmZMEpGoQqoKhaBaEQEDLwrLrTOUoIidR62aMIqWmxWv01agehNfLzXc 2hAjfMTCVFyBkRwJUijDML5Amcdq1xa+yrBfrYRUyIS2yytQKUBiBrLuTLZVhChmPWUBAoh7xePft 4rURTs+zavf0o03CiVOK+aDT1/1yJfqiMJ3RC0vUeb+Ki9uNS6O0b94VbXvADP40EfQH2H1knYQDH WPH9Ym8+Q==; Received: from [64.114.255.114] (helo=worktop) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1gLcYm-0000xX-3s; Sat, 10 Nov 2018 23:21:00 +0000 Received: by worktop (Postfix, from userid 1000) id 59EFB6E07D5; Sun, 11 Nov 2018 00:20:59 +0100 (CET) Date: Sun, 11 Nov 2018 00:20:59 +0100 From: Peter Zijlstra To: Ard Biesheuvel Cc: Ingo Molnar , Josh Poimboeuf , Linux Kernel Mailing List , the arch/x86 maintainers , Andy Lutomirski , Steven Rostedt , Thomas Gleixner , Linus Torvalds , Masami Hiramatsu , Jason Baron , Jiri Kosina , David Laight , Borislav Petkov Subject: Re: [PATCH RFC 0/3] Static calls Message-ID: <20181110232059.GA12766@worktop.psav.com> References: <20181109072811.GB86700@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.22.1 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 09, 2018 at 02:50:27PM +0100, Ard Biesheuvel wrote: > On 9 November 2018 at 08:28, Ingo Molnar wrote: > >> - I'm not sure about the objtool approach. Objtool is (currently) > >> x86-64 only, which means we have to use the "unoptimized" version > >> everywhere else. I may experiment with a GCC plugin instead. > > > > I'd prefer the objtool approach. It's a pretty reliable first-principles > > approach while GCC plugin would have to be replicated for Clang and any > > other compilers, etc. > > > > I implemented the GCC plugin approach here for arm64 I'm confused; I though we only needed objtool for variable instruction length architectures, because we can't reliably decode our instruction stream. Otherwise we can fairly trivially use the DWARF relocation data, no?