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 5A727C28CBC for ; Wed, 6 May 2020 16:29:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 210B9206B9 for ; Wed, 6 May 2020 16:29:06 +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="CW58Ldmu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729816AbgEFQ3F (ORCPT ); Wed, 6 May 2020 12:29:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40632 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1729405AbgEFQ3E (ORCPT ); Wed, 6 May 2020 12:29:04 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E0DC5C061A0F for ; Wed, 6 May 2020 09:29:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.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=fd3UEHcmje3N6DjodZqeqpJ6DqtVWXpYm4oCZPMA85o=; b=CW58LdmuHIwthGYqKK52pcoC6a c38F3/pcQrnOHfLd58+UKTjQofsztvYgvL2aEMI2OxbvLdOAYVhnA0ZlbRqTg4UW/xw5XDAlgCXlq hmrDc23NU4IIHv3kPU4SWUYw8aUW1311LIHjxTLSmRY15t9tA68GbNQJiwESLEGoAOVeJVa5akiP0 nVxLCR04y20Wb5pawkBSGwmZ9WcCzTjjyxHOSEwPizwTQ3hR/+RZjPUZc1PwGrdlx/1F5xIe0VcyX oUCUhhNkgI5IkIBvHklo+Mz+6YqvMBeH9uKKi35ys+ysTqIir1SdGTZQBJ87oRLebGnzd+wquHz3B OTO35FLQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jWMug-0005pu-Jo; Wed, 06 May 2020 16:28:50 +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 B6CA5300739; Wed, 6 May 2020 18:28:48 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 90E2B29DAC127; Wed, 6 May 2020 18:28:48 +0200 (CEST) Date: Wed, 6 May 2020 18:28:48 +0200 From: Peter Zijlstra To: Sean Christopherson Cc: Thomas Gleixner , LKML , x86@kernel.org, "Paul E. McKenney" , Andy Lutomirski , Alexandre Chartre , Frederic Weisbecker , Paolo Bonzini , Masami Hiramatsu , Petr Mladek , Steven Rostedt , Joel Fernandes , Boris Ostrovsky , Juergen Gross , Brian Gerst , Mathieu Desnoyers , Josh Poimboeuf , Will Deacon Subject: Re: [patch V4 part 1 20/36] vmlinux.lds.h: Create section for protection against instrumentation Message-ID: <20200506162848.GI5298@hirez.programming.kicks-ass.net> References: <20200505131602.633487962@linutronix.de> <20200505134100.075416272@linutronix.de> <20200506160831.GB3329@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200506160831.GB3329@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 06, 2020 at 09:08:31AM -0700, Sean Christopherson wrote: > On Tue, May 05, 2020 at 03:16:22PM +0200, Thomas Gleixner wrote: > > Provide also a set of markers: instr_begin()/end() > > > > These are used to mark code inside a noinstr function which calls > > into regular instrumentable text section as safe. > > ... > > > --- a/include/linux/compiler.h > > +++ b/include/linux/compiler.h > > @@ -120,10 +120,27 @@ void ftrace_likely_update(struct ftrace_ > > /* Annotate a C jump table to allow objtool to follow the code flow */ > > #define __annotate_jump_table __section(.rodata..c_jump_table) > > > > +/* Begin/end of an instrumentation safe region */ > > +#define instr_begin() ({ \ > > + asm volatile("%c0:\n\t" \ > > + ".pushsection .discard.instr_begin\n\t" \ > > + ".long %c0b - .\n\t" \ > > + ".popsection\n\t" : : "i" (__COUNTER__)); \ > > +}) > > + > > +#define instr_end() ({ \ > > + asm volatile("%c0:\n\t" \ > > + ".pushsection .discard.instr_end\n\t" \ > > + ".long %c0b - .\n\t" \ > > + ".popsection\n\t" : : "i" (__COUNTER__)); \ > > +}) > > Any chance we could spell these out, i.e. instrumentation_begin/end()? I > can't help but read these as "instruction_begin/end". At a glance, the > long names shouldn't cause any wrap/indentation issues. The kernel naming convention is insn for instruction, not instr. That said, you're not the first to be confused by this.