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=-0.7 required=3.0 tests=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 E9CC8C3A59E for ; Mon, 2 Sep 2019 23:54:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C922621881 for ; Mon, 2 Sep 2019 23:54:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727926AbfIBXyC (ORCPT ); Mon, 2 Sep 2019 19:54:02 -0400 Received: from bilbo.ozlabs.org ([203.11.71.1]:36863 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726775AbfIBXyB (ORCPT ); Mon, 2 Sep 2019 19:54:01 -0400 Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 46Mn3n2Lzbz9s7T; Tue, 3 Sep 2019 09:53:57 +1000 (AEST) From: Michael Ellerman To: Segher Boessenkool Cc: Michal Suchanek , linuxppc-dev@lists.ozlabs.org, Benjamin Herrenschmidt , Paul Mackerras , Alexander Viro , Nicholas Piggin , Christophe Leroy , Breno Leitao , Arnd Bergmann , Heiko Carstens , Greg Kroah-Hartman , Firoz Khan , Thomas Gleixner , Joel Stanley , Hari Bathini , Michael Neuling , Andrew Donnellan , Russell Currey , Diana Craciun , "Eric W. Biederman" , David Hildenbrand , Allison Randal , Andrew Morton , Madhavan Srinivasan , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH v7 5/6] powerpc/64: Make COMPAT user-selectable disabled on littleendian by default. In-Reply-To: <20190902130008.GZ31406@gate.crashing.org> References: <87ftlftpy7.fsf@mpe.ellerman.id.au> <20190902130008.GZ31406@gate.crashing.org> Date: Tue, 03 Sep 2019 09:53:56 +1000 Message-ID: <87k1aqs19n.fsf@mpe.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Segher Boessenkool writes: > On Mon, Sep 02, 2019 at 12:03:12PM +1000, Michael Ellerman wrote: >> Michal Suchanek writes: >> > On bigendian ppc64 it is common to have 32bit legacy binaries but much >> > less so on littleendian. >> >> I think the toolchain people will tell you that there is no 32-bit >> little endian ABI defined at all, if anything works it's by accident. ^ v2 > There of course is a lot of powerpcle-* support. The ABI used for it > on linux is the SYSV ABI, just like on BE 32-bit. I was talking about ELFv2, which is 64-bit only. But that was based on me thinking we had a hard assumption in the kernel that ppc64le kernels always expect ELFv2 userland. Looking at the code though I was wrong about that, it looks like we will run little endian ELFv1 binaries, though I don't think anyone is testing it. > There also is specific powerpcle-linux support in GCC, and in binutils, > too. Also, config.guess/config.sub supports it. Half a year ago this > all built fine (no, I don't test it often either). > > I don't think glibc supports it though, so I wonder if anyone builds an > actual system with it? Maybe busybox or the like? > >> So I think we should not make this selectable, unless someone puts their >> hand up to say they want it and are willing to test it and keep it >> working. > > What about actual 32-bit LE systems? Does anyone still use those? Not that I've ever heard of. cheers