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=-5.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 28C8FC169C4 for ; Mon, 11 Feb 2019 18:37:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E8BA621B18 for ; Mon, 11 Feb 2019 18:37:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="r2L6NSU+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732502AbfBKShx (ORCPT ); Mon, 11 Feb 2019 13:37:53 -0500 Received: from mail.skyhub.de ([5.9.137.197]:45408 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729552AbfBKShx (ORCPT ); Mon, 11 Feb 2019 13:37:53 -0500 Received: from zn.tnic (p200300EC2BC7A10074DEFDFE3AD6CF32.dip0.t-ipconnect.de [IPv6:2003:ec:2bc7:a100:74de:fdfe:3ad6:cf32]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 21C861EC01B6; Mon, 11 Feb 2019 19:37:51 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1549910271; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=MfO9iraTHgQ5nRXoFHrsSYSHTedG1aQEDckVc6y+oB0=; b=r2L6NSU+gQRc9eP6vhleihhYe7ChDGrNf8u5AA7D2wpuQbAZ9Bm0Fz5kkiiOWDABu5rgBs As+h0/3tG84bT+jrIjuMOOYQO8XGlUjnVh44QvtfpZ1OITxv8f66lXFCe/4GWyL1/RzF2I qLvosFPyppk1t5t1d/CoLxnOtlB6MAQ= Date: Mon, 11 Feb 2019 19:37:50 +0100 From: Borislav Petkov To: Rick Edgecombe Cc: Andy Lutomirski , Ingo Molnar , linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com, Thomas Gleixner , Nadav Amit , Dave Hansen , Peter Zijlstra , linux_dti@icloud.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, akpm@linux-foundation.org, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, will.deacon@arm.com, ard.biesheuvel@linaro.org, kristen@linux.intel.com, deneen.t.dock@intel.com, Nadav Amit , Kees Cook , Dave Hansen , Masami Hiramatsu Subject: Re: [PATCH v2 11/20] x86/jump-label: remove support for custom poker Message-ID: <20190211183749.GO19618@zn.tnic> References: <20190129003422.9328-1-rick.p.edgecombe@intel.com> <20190129003422.9328-12-rick.p.edgecombe@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190129003422.9328-12-rick.p.edgecombe@intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org On Mon, Jan 28, 2019 at 04:34:13PM -0800, Rick Edgecombe wrote: > From: Nadav Amit > > There are only two types of poking: early and breakpoint based. The use > of a function pointer to perform poking complicates the code and is > probably inefficient due to the use of indirect branches. > > Cc: Andy Lutomirski > Cc: Kees Cook > Cc: Dave Hansen > Cc: Masami Hiramatsu > Acked-by: Peter Zijlstra (Intel) > Signed-off-by: Nadav Amit > Signed-off-by: Rick Edgecombe > --- > arch/x86/kernel/jump_label.c | 24 ++++++++---------------- > 1 file changed, 8 insertions(+), 16 deletions(-) ... > @@ -80,16 +71,17 @@ static void __ref __jump_label_transform(struct jump_entry *entry, > bug_at((void *)jump_entry_code(entry), line); > > /* > - * Make text_poke_bp() a default fallback poker. > + * As long as we're UP and not yet marked RO, we can use > + * text_poke_early; SYSTEM_BOOTING guarantees both, as we switch to > + * SYSTEM_SCHEDULING before going either. s/going/doing/ ? -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.