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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1862CC433F5 for ; Tue, 2 Nov 2021 21:18:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E35EC61051 for ; Tue, 2 Nov 2021 21:18:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231219AbhKBVU5 (ORCPT ); Tue, 2 Nov 2021 17:20:57 -0400 Received: from mail.skyhub.de ([5.9.137.197]:37678 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229931AbhKBVUy (ORCPT ); Tue, 2 Nov 2021 17:20:54 -0400 Received: from zn.tnic (p200300ec2f1e1e0080adfba3347e3dab.dip0.t-ipconnect.de [IPv6:2003:ec:2f1e:1e00:80ad:fba3:347e:3dab]) (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 4C4AD1EC0372; Tue, 2 Nov 2021 22:18:18 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1635887898; 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=+/uDq33xUD46XLKdHYR9LMs4FyeNj1wjtbIaLFhaSWU=; b=mXz/zjz0JdyUSUexsPc4zLrAmMcEklloNANLpGI8mtCpf6bWFQ0UShVIu+z0cuoZYhLDgT gL22/17Lk0ZAOlBLZ+fXQVHtehCZxGGmB+fz/OsOG42ryphNXlXed5gg508eT3iRJDFwNL yZK+7ypcGCRAoC0E/YJXQmPkPiY+vbw= Date: Tue, 2 Nov 2021 22:18:12 +0100 From: Borislav Petkov To: Linus Torvalds Cc: Peter Zijlstra , Thomas Gleixner , Josh Poimboeuf , Linux Kernel Mailing List , the arch/x86 maintainers , Alexander Popov Subject: Re: Stackleak vs noinstr (Was: [GIT pull] objtool/core for v5.16-rc1) Message-ID: References: <163572864256.3357115.931779940195622047.tglx@xen13> <163572864563.3357115.8793939214537874196.tglx@xen13> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 02, 2021 at 10:50:06AM -0700, Linus Torvalds wrote: > On Tue, Nov 2, 2021 at 3:05 AM Peter Zijlstra wrote: > > > > Having the plugin gate on section name seems a lot hacky, but given it's > > already doing that, one more doesn't hurt. > > Looks sane to me. > > Some of the other warnings are just odd. > > Why is mce_setup() 'noinst'? I'm not seeing any reason for it, but > maybe I'm just blind. That one complains about the memcpy() call. > > Of course, I suspect memcpy/memset might be better off noinstr anyway, > exactly because they can happen for very regular C code (struct > assignments etc). But mce_setup() doesn't really seem to have much > reason to not be instrumented. That is going away in my local patchset here. The aim is to have the #MC handler be noinstr, ofc, but that thing calls a bunch of other functions and even external ones so it needs careful massaging without destroying the whole house of cards in the process. :-) I should have something palatable - read: properly split patches - soon. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette