From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759717Ab0COFy0 (ORCPT ); Mon, 15 Mar 2010 01:54:26 -0400 Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:36908 "EHLO sunset.davemloft.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759685Ab0COFyW (ORCPT ); Mon, 15 Mar 2010 01:54:22 -0400 Date: Sun, 14 Mar 2010 22:54:43 -0700 (PDT) Message-Id: <20100314.225443.150715656.davem@davemloft.net> To: benh@kernel.crashing.org Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, kernel@teksavvy.com, drepper@redhat.com, torvalds@linux-foundation.org, munroesj@linux.vnet.ibm.com Subject: Re: 64-syscall args on 32-bit vs syscall() From: David Miller In-Reply-To: <1268630313.2335.2.camel@pasglop> References: <1268628493.2355.2.camel@pasglop> <20100314.220646.190065794.davem@davemloft.net> <1268630313.2335.2.camel@pasglop> X-Mailer: Mew version 6.3 on Emacs 23.1 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Benjamin Herrenschmidt Date: Mon, 15 Mar 2010 16:18:33 +1100 > Or is there any good reason -not- to do that in glibc ? The whole point of syscall() is to handle cases where the C library doesn't know about the system call yet. I think it's therefore very much "buyer beware". On sparc it'll never work to use the workaround you're proposing since we pass everything in via registers. So arch knowledge will always need to be present in these situations.