From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Munroe Subject: Re: 64-syscall args on 32-bit vs syscall() Date: Tue, 16 Mar 2010 16:56:10 -0500 Message-ID: <1268776570.19726.98.camel@spokane1.rchland.ibm.com> References: <20100315134449.GB1653@linux-mips.org> <4B9E4EB1.9010800@zytor.com> <4B9E59B7.6060405@redhat.com> <20100315.120004.209998642.davem@davemloft.net> <4B9E8D67.8040209@zytor.com> <1268685311.2335.38.camel@pasglop> Reply-To: munroesj@us.ibm.com Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from e33.co.us.ibm.com ([32.97.110.151]:46561 "EHLO e33.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751186Ab0CPVrG (ORCPT ); Tue, 16 Mar 2010 17:47:06 -0400 In-Reply-To: <1268685311.2335.38.camel@pasglop> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Benjamin Herrenschmidt Cc: "H. Peter Anvin" , David Miller , drepper@redhat.com, ralf@linux-mips.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, kernel@teksavvy.com, torvalds@linux-foundation.org On Tue, 2010-03-16 at 07:35 +1100, Benjamin Herrenschmidt wrote: > On Mon, 2010-03-15 at 12:41 -0700, H. Peter Anvin wrote: > > I don't see why syscall() can't change the type for its first argument > > -- it seems to be exactly what symbol versioning is for. > > > > Doesn't change the fact that it is fundamentally broken, of course. > > No need to change the type of the first arg and go for symbol > versionning if you do something like I proposed earlier, there will be > no conflict between syscall() and __syscall() and both variants can > exist. > One concern is the new syscall and the kernel have to match and mixing will not work. your proposal seems to impact all syscalls not just the one called via syscall API. These syscalls get generated inline which makes static linking very dangerous ... So I think you do need both symbol versioning and kernel feature stubs (like xstat). That gets to be a lot of work > Cheers, > Ben. > >