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 EBFFAC433EF for ; Wed, 20 Oct 2021 19:23:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CEF9861354 for ; Wed, 20 Oct 2021 19:23:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231565AbhJTT0I (ORCPT ); Wed, 20 Oct 2021 15:26:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35416 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231485AbhJTT0G (ORCPT ); Wed, 20 Oct 2021 15:26:06 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9CB27C06161C for ; Wed, 20 Oct 2021 12:23:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; 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=80kq77wLo4tISSEgSJEwjE/WA2Ew5k8rlteIWmD2+uM=; b=DgRUBxvMRdXzg7dP/aNv8Rz1Uy kAdAN9Vuznnf+PmTTfBBpJGg/X+z2AhB0JcPgnWPQAZGVLbh13nK2zDSR+VeRn2/R8bZj7AFrwGe1 jugXfqKVH9hEHZw+QHreYlJxrUN7Ds3nkIP/B49C7pdEsjUmKT59/EXDmwgl6M85rAeJ4O1EPc+Fr IJ/xhL/tuHc6VyZQMAcFMJjs/moG3uDuogDRcN7zckvHnoifVuxvmdTF5T8ole3Y5xwLPhWeV22mw FuBO1IqRfCNn27zmWT9ojRi8VxzhmMzbK5bS2kKr3IB9hs9ra+IrmXJGH7WQveIs5evP67Y0nIsI/ VtG4mdkg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=worktop.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1mdHBd-00B0gk-JJ; Wed, 20 Oct 2021 19:23:42 +0000 Received: by worktop.programming.kicks-ass.net (Postfix, from userid 1000) id 6C98D986DD9; Wed, 20 Oct 2021 21:23:41 +0200 (CEST) Date: Wed, 20 Oct 2021 21:23:41 +0200 From: Peter Zijlstra To: Josh Poimboeuf Cc: x86@kernel.org, andrew.cooper3@citrix.com, linux-kernel@vger.kernel.org, alexei.starovoitov@gmail.com, ndesaulniers@google.com Subject: Re: [PATCH v2 14/14] bpf,x86: Respect X86_FEATURE_RETPOLINE* Message-ID: <20211020192341.GQ174703@worktop.programming.kicks-ass.net> References: <20211020104442.021802560@infradead.org> <20211020105843.345016338@infradead.org> <20211020165655.632slp4ujsajis4j@treble> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211020165655.632slp4ujsajis4j@treble> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Oct 20, 2021 at 09:56:55AM -0700, Josh Poimboeuf wrote: > On Wed, Oct 20, 2021 at 01:09:51PM +0200, Peter Zijlstra wrote: > > Alexei; could the above not be further improved with something like the > > below? > > > > Despite several hours trying and Song helping, I can't seem to run > > anything bpf, that stuff is cursed. So I've no idea if the below > > actually works, but it seems reasonable. > > The below fix gets it to run with test_verififer. Argh, I;m fast running out of brown paper bags at this rate :/ > > I do like it, it does seem less fiddly and more robust against future > changes, though it probably needs a comment for 'out_label' clarifying > it only works because this function is always called at least twice for > a given bpf_tail_call emission. Right.