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[209.132.180.67]) by mx.google.com with ESMTP id j3si6901696pfa.194.2019.03.08.07.24.05; Fri, 08 Mar 2019 07:24:21 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=fail header.i=@infradead.org header.s=bombadil.20170209 header.b=r70GPl5j; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726378AbfCHPXc (ORCPT + 99 others); Fri, 8 Mar 2019 10:23:32 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:55454 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726270AbfCHPXb (ORCPT ); Fri, 8 Mar 2019 10:23:31 -0500 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: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=BkWjg8JnuN9Uuj60Hju+NBy0JAN4stAxWziAH7bC9DY=; b=r70GPl5jIFFYednI9WTMgDbDy V207545Ygxp70Ckzct4xKYYSS5sbMXMksVyAcYg76s8jJylIrX0AFnx4UC3pNawk6sRiG3e5zuYbH ymsoTaTaVwiPnJzOc5MQa5ZvhdEtq3thB5vmIU+3zn4+YFImXf1WzTB2530HKp/Q/qGFsRrZqUDn5 sE7f33TQRJ2RFm34gBjN9A+M6LKe3d34lS9ZuACLQIw5Cwsc4+7pKAPIVpO1CTNtQ1uLVb0+M8bIR VKwgU0wff55Q82MMK5UIZZ7SqMzpHG2lwoHaj+COiS0m0uMTfxsCIGWV/s4hTrtC5raFUFKI4Adec Hi4jw5Ssg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1h2HLE-0005vf-9x; Fri, 08 Mar 2019 15:23:20 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id CD8D8202631D4; Fri, 8 Mar 2019 16:23:18 +0100 (CET) Date: Fri, 8 Mar 2019 16:23:18 +0100 From: Peter Zijlstra To: Josh Poimboeuf Cc: Linus Torvalds , Thomas Gleixner , Peter Anvin , Julien Thierry , Will Deacon , Andy Lutomirski , Ingo Molnar , Catalin Marinas , James Morse , valentin.schneider@arm.com, Brian Gerst , Andrew Lutomirski , Borislav Petkov , Denys Vlasenko , Linux List Kernel Mailing , Dmitry Vyukov , Steven Rostedt Subject: Re: [PATCH 18/20] objtool: Add UACCESS validation Message-ID: <20190308152318.GC32494@hirez.programming.kicks-ass.net> References: <20190307114511.870090179@infradead.org> <20190307115200.697533978@infradead.org> <20190307174135.GJ32477@hirez.programming.kicks-ass.net> <20190307184813.GL32477@hirez.programming.kicks-ass.net> <20190307202319.GD32534@hirez.programming.kicks-ass.net> <20190307204021.GE32534@hirez.programming.kicks-ass.net> <20190308150703.3jozuvj2crcxvlzp@treble> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190308150703.3jozuvj2crcxvlzp@treble> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 08, 2019 at 09:07:03AM -0600, Josh Poimboeuf wrote: > On Thu, Mar 07, 2019 at 09:40:21PM +0100, Peter Zijlstra wrote: > > On Thu, Mar 07, 2019 at 09:23:19PM +0100, Peter Zijlstra wrote: > > > On Thu, Mar 07, 2019 at 07:48:13PM +0100, Peter Zijlstra wrote: > > > > Another thing I need to look at is why objtool only found memset_orig > > > > (from __memset) but not memset_erms, which if I read the code right, is > > > > a possible alternative there. > > > > > > Turns out we only look for sibling calls in the original instruction > > > stream, not in any alternatives; which in general seems like a fair > > > enough assumption. > > > > And while I'm looking at memset_64.S, why are memset_erms and > > memset_orig global functions? At the very least they should be local, > > and ideally not even functions. > > I think the only benefit is that they would show up better on stack > traces, but that could also be solved by just making them local labels > inside memset. Which is what I think they should be. Boris wanted to use alternative_call_2, just like copy_user_generic(). Which makes more sense to me still.