From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from p508B7B0E.dip.t-dialin.net ([80.139.123.14]:10550 "EHLO mail.linux-mips.net") by vger.kernel.org with ESMTP id S264061AbUFCSOB (ORCPT ); Thu, 3 Jun 2004 14:14:01 -0400 Date: Thu, 3 Jun 2004 20:13:45 +0200 From: Ralf Baechle Subject: Re: FUTEX_CMP_REQUEUE and 6-argument syscall Message-ID: <20040603181345.GA26083@linux-mips.org> References: <20040603110221.1fe58b53.zaitcev@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040603110221.1fe58b53.zaitcev@redhat.com> To: Pete Zaitcev Cc: schwidefsky@de.ibm.com, linux-arch@vger.kernel.org, akpm@osdl.org, jakub@redhat.com List-ID: On Thu, Jun 03, 2004 at 11:02:21AM -0700, Pete Zaitcev wrote: > So, now we have a syscall with 6 arguments. Do you have any suggestions > how to handle it on s390? The main decision would be if we stick to > the C calling convention and put a pointer to the list into %r7, or > if we just put the argument into %r7 (thus precluding syscalls with > 7 arguments for sure, but saving a get_user somewhere). After that > we need to change arch/s390/kernel/entry.S:trace_svc, and the 31 bit > compat wrapper. > > I'm curious if any other architecture was caught out by this. 6 is the limit on o32 MIPS where we pass 4 arguments in registers and two on the stack but it would be easy to extend that. On 64-bit kernels we only use upto 8 register arguments but no stack arguments ever so I hope we don't exceed that limit ever ... Ralf