From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754880AbZEIKsU (ORCPT ); Sat, 9 May 2009 06:48:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753267AbZEIKsF (ORCPT ); Sat, 9 May 2009 06:48:05 -0400 Received: from astoria.ccjclearline.com ([64.235.106.9]:53932 "EHLO astoria.ccjclearline.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751469AbZEIKsD (ORCPT ); Sat, 9 May 2009 06:48:03 -0400 Date: Sat, 9 May 2009 06:46:49 -0400 (EDT) From: "Robert P. J. Day" X-X-Sender: rpjday@localhost.localdomain To: Sam Ravnborg cc: Linux Kernel Mailing List Subject: Re: __setup_param(), unique_id and vdso_setup In-Reply-To: <20090509073227.GA22397@uranus.ravnborg.org> Message-ID: References: <20090509073227.GA22397@uranus.ravnborg.org> User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - astoria.ccjclearline.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - crashcourse.ca X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org regarding the sole remaining invocation of __setup_param() in the entire tree that could possibly be removed, taking the definition of __setup_param() with it: On Sat, 9 May 2009, Sam Ravnborg wrote: > On Wed, May 06, 2009 at 03:24:21PM -0400, Robert P. J. Day wrote: > > ... > > ===== > > > > in short, both invocations of __setup_param() use identical second > > and third parameters, and a tree-wide grep shows: > > > > $ grep -rw __setup_param * > > arch/x86/vdso/vdso32-setup.c:__setup_param("vdso=", vdso32_setup, vdso_setup, 0); > > include/linux/init.h:#define __setup_param(str, unique_id, fn, early) \ > > include/linux/init.h: __setup_param(str, fn, fn, 0) > > include/linux/init.h: __setup_param(str, fn, fn, 1) > > include/linux/init.h:#define __setup_param(str, unique_id, fn) /* nothing */ > > $ > > > > so apart from that single exception involving "vdso", that macro > > could be simplified to just get rid of that third parameter. is > > there something special about the vdso boot-time parm that > > *requires* it to be the only boot-time parm in the entire kernel > > to have a different unique id? just curious. or does that have > > to be preserved for out-of-tree builds? > No - so please go ahead and clean it up. i'd be happy to, except i'm not sure how to resolve that last invocation to no longer use __setup_param(). from arch/x86/vdso/vdso32-setup.c: ===== ... unsigned int __read_mostly vdso_enabled = VDSO_DEFAULT; static int __init vdso_setup(char *s) { vdso_enabled = simple_strtoul(s, NULL, 0); return 1; } /* * For consistency, the argument vdso32=[012] affects the 32-bit vDSO * behavior on both 64-bit and 32-bit kernels. * On 32-bit kernels, vdso=[012] means the same thing. */ __setup("vdso32=", vdso_setup); #ifdef CONFIG_X86_32 __setup_param("vdso=", vdso32_setup, vdso_setup, 0); EXPORT_SYMBOL_GPL(vdso_enabled); #endif ... ===== if someone wants to resolve that file to remove the use of __setup_param(), this cleanup should be done in two steps, anyway. first, get rid of that final invocation, followed by removing the definition from moduleparam.h. suggestions? rday p.s. there are only three architectures that appear to support a boot-time parm of vdso (or some equivalent): $ grep -rw __setup * | grep vdso arch/sh/kernel/vsyscall/vsyscall.c:__setup("vdso=", vdso_setup); arch/x86/vdso/vdso32-setup.c:__setup("vdso32=", vdso_setup); arch/x86/vdso/vma.c:__setup("vdso=", vdso_setup); arch/s390/kernel/vdso.c:__setup("vdso=", vdso_setup); $ that doesn't quite match with what one finds in Documentation/kernel-parameters.txt: vdso= [X86,SH] vdso=2: enable compat VDSO (default with COMPAT_VDSO) vdso=1: enable VDSO (default) vdso=0: disable VDSO mapping vdso32= [X86] vdso32=2: enable compat VDSO (default with COMPAT_VDSO) vdso32=1: enable 32-bit VDSO (default) vdso32=0: disable 32-bit VDSO mapping just an observation. -- ======================================================================== Robert P. J. Day Waterloo, Ontario, CANADA Linux Consulting, Training and Annoying Kernel Pedantry. Web page: http://crashcourse.ca Linked In: http://www.linkedin.com/in/rpjday Twitter: http://twitter.com/rpjday ========================================================================