From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757414AbYELW4o (ORCPT ); Mon, 12 May 2008 18:56:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755941AbYELW4e (ORCPT ); Mon, 12 May 2008 18:56:34 -0400 Received: from moutng.kundenserver.de ([212.227.126.179]:60295 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755538AbYELW4d convert rfc822-to-8bit (ORCPT ); Mon, 12 May 2008 18:56:33 -0400 From: Arnd Bergmann To: John Williams Subject: Re: Microblaze toolchain - libc Date: Tue, 13 May 2008 00:56:12 +0200 User-Agent: KMail/1.9.9 Cc: monstr@seznam.cz, Stephen Neuendorffer , John Linn , Linux Kernel list , microblaze-uclinux@itee.uq.edu.au, Grant Likely References: <4826FD34.5030009@seznam.cz> <1210545788.5798.273.camel@localhost> In-Reply-To: <1210545788.5798.273.camel@localhost> X-Face: I@=L^?./?$U,EK.)V[4*>`zSqm0>65YtkOe>TFD'!aw?7OVv#~5xd\s,[~w]-J!)|%=]>=?utf-8?q?+=0A=09=7EohchhkRGW=3F=7C6=5FqTmkd=5Ft=3FLZC=23Q-=60=2E=60Y=2Ea=5E?= =?utf-8?q?3zb?=) =?utf-8?q?+U-JVN=5DWT=25cw=23=5BYo0=267C=26bL12wWGlZi=0A=09=7EJ=3B=5Cwg?= =?utf-8?q?=3B3zRnz?=,J"CT_)=\H'1/{?SR7GDu?WIopm.HaBG=QYj"NZD_[zrM\Gip^U MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: 8BIT Content-Disposition: inline Message-Id: <200805130056.13950.arnd@arndb.de> X-Provags-ID: V01U2FsdGVkX192Zza7nSnkm2/LZHg25vpWmi57UXuoMsA6NZe 97zJZdFrtILiGKf9uZlctWq5WEO6pet39UeUTpEZekI6g2aUYP Wh4KrOFOHdR3xN+V6l3hw== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Monday 12 May 2008, John Williams wrote: > > is it any movement in libc? > > I would like clear code around syscalls. > > I can't see anything radical happening with glibc / uClibc in the short > term.  My suggestion is you make sure the kernel builds with current > toolchain.   What happened to the idea of making it an add-on patch for the short term then? I think you should use the short generic syscall list in the mainline series, and add source level support for uClibc back in as an out-of-tree patch, under an #ifdef. I guess that you can mostly do this by adding back the currently required syscalls for uClibc at the end of sys_call_table, and introducing a new file with the old implementation of the removed arch specific calls (ipc, vfork, mmap, ...). BTW: after a private discussion I had with some other kernel hackers, I believe now that it will be easier for you to leave off_t as 32 bit but instead make sure that you only list the syscalls using loff_t, e.g. stat64 instead of new_stat, contrary to what I claimed earlier. You should probably try that yourself and do whatever is easier to implement in uClibc. > I'm not personally concerned about minor bloat of adding syscalls like > openat() that are not currently used - 1 or 2 K for extra entries in > syscall table, and a few hundred bytes per sys_wrapper really is not on > the radar if glibc is considered a sensible library for Microblaze + > MMU! You still have it backwards -- you need to have openat() anyway because applications can legally call that function, and if uClibc doesn't have it, that's just a bug. The discussion was about leaving out the open() syscall in favour of a libc based implementation based on openat(). Besides, these syscalls don't matter much, as you said those only save a few bytes. The real killers are uid16, 32 bit off_t, old style signals and some minor annoyances things like sys_ipc(). If you change those, you might just as well get it right because you're breaking compatibility already. Arnd <><