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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 3B732C433DB for ; Wed, 10 Mar 2021 10:06:10 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7DF3864FD7 for ; Wed, 10 Mar 2021 10:06:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7DF3864FD7 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arndb.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4DwSQR662bz3d94 for ; Wed, 10 Mar 2021 21:06:07 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=arndb.de (client-ip=217.72.192.74; helo=mout.kundenserver.de; envelope-from=arnd@arndb.de; receiver=) X-Greylist: delayed 314 seconds by postgrey-1.36 at boromir; Wed, 10 Mar 2021 21:05:47 AEDT Received: from mout.kundenserver.de (mout.kundenserver.de [217.72.192.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4DwSQ34Qzwz30Hc for ; Wed, 10 Mar 2021 21:05:46 +1100 (AEDT) Received: from mail-oi1-f169.google.com ([209.85.167.169]) by mrelayeu.kundenserver.de (mreue108 [213.165.67.113]) with ESMTPSA (Nemesis) id 1M593i-1lL26D2MJY-001CoB for ; Wed, 10 Mar 2021 11:00:21 +0100 Received: by mail-oi1-f169.google.com with SMTP id w65so18457337oie.7 for ; Wed, 10 Mar 2021 02:00:20 -0800 (PST) X-Gm-Message-State: AOAM532u8J/pxkY7GNiPWUZxELKsAyxCSEbZs9H3FWkvpNcYDomRY4pJ 38cTicdcOdfyK0G8tV+5elym/AggiM6MsSwRbg8= X-Google-Smtp-Source: ABdhPJz57LKzxKPOX8uFg4l8cQDX68aMXQSUFxgEEkBEVQzSWLTS5wn+SJ00u096OqMsz2UiKEGrsCkrnzqbLH7kTeM= X-Received: by 2002:aca:bf44:: with SMTP id p65mr1764631oif.11.1615370419432; Wed, 10 Mar 2021 02:00:19 -0800 (PST) MIME-Version: 1.0 References: <5811950d-ef14-d416-35e6-d694ef920a7d@csgroup.eu> <13737de5-0eb7-e881-9af0-163b0d29a1a0@csgroup.eu> In-Reply-To: <13737de5-0eb7-e881-9af0-163b0d29a1a0@csgroup.eu> From: Arnd Bergmann Date: Wed, 10 Mar 2021 11:00:03 +0100 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v3] powerpc/32: remove bogus ppc_select syscall To: Christophe Leroy Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:0EEgx3Qqq6jhXRtRfw8EkLnjrA91cQVRi5H2VBoKCYl/CU7XNmJ 8weSGHNJT7tF/h1KnCrTlzr5HEuIAAP7Hexi8gTSXINCdq9rKNt3TKW3L+qTGrbHdjlPtLl Eqa0kY6hBTNnaaI6WiDa/wqN+hLt6K7vCBnXvJRg5+ebT89UYr8ed9XgX10tNsu4fQRpb/Z UG0Kw7EzpnwADS2Ju4JhA== X-UI-Out-Filterresults: notjunk:1;V03:K0:goVcUrqw8XI=:u1rAoIqTjoVsFFq5B6mHQY ulLWltGhLSNEjG6aUOdZ9mzv20PIpoZ8ty7XvAzZxbyGYqiwKXpqietq4goymLHygwH1FHr7l dvt9oKMWlwmTxgg43Hjv6C9JnRRCPAkv4xm5rBZ9qgCS2E0FKTOjzxed6nd8/EdyW7vQGzxl3 zY9hzRZTVF+XpMr3KFiT/ICtUQqWDkoLyJglijwdVy7mlvWQqFyK8muXrk5MWqrWH3TwLFNjs rlA9cE99npCGfO16FBxAbVSiCRexFVi99wYlyyQCugNSdktsohyX87vWt5XJ0j6zCZASseloI FPNtjk6Whojwxxuu/1+PFHCe1Tv91Aw42gImNDw6NBLkuF2h2LEXmkD2B/unTtnxYA+d5hWQG R4ObqRHAfj3K3PudHfhTxCAbVPgc5B8KCTGmgoU4OJj5G3jDWkchkcPL4Ywyv X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linuxppc-dev , "linux-kernel@vger.kernel.org" Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Tue, Mar 9, 2021 at 4:59 PM Christophe Leroy wrote: > Le 05/03/2021 =C3=A0 13:03, Arnd Bergmann a =C3=A9crit : > > On Fri, Mar 5, 2021 at 11:15 AM Christophe Leroy > > wrote: > >> Le 05/03/2021 =C3=A0 11:06, Arnd Bergmann a =C3=A9crit : > > I had another look. In fact x86, arm and m68k still have the #82 syscall,= but they don't have the > hack we have on powerpc to "guess" that something is calling the old sele= ct with the arguments of > the new select. Makes sense. At least for x86, there are probably still some pre-glibc binaries around that would use the old select. > As part of my series of user accesses cleanup, I'll replace the open code= d stuff by a call to > sys_old_select(), see below. Nice! > Maybe at the end we should keep the #82 syscall, but do we need to keep t= he powerpc hack really ? > Maybe the best is to drop ppc_select() function but mention sys_old_selec= t() instead of ni_syscall > for entry #82 in the syscall table ? I'd say we should either keep the powerpc hack intact (with your cleanup), or remove the syscall entirely. I have been unable to find any indication o= f who might have called the #82 syscall prior to mklinux DR2.1 and linuxppc R= 4, so there is no way of knowing which of the two ABIs they were using either. It was definitely ambiguous since the ancient kernels only had sys_select() semantics at #82, but the existence of the hack tells us that there were at least some binaries that wanted the sys_oldselect() semantics. Arnd