Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753120AbZDZJHX (ORCPT ); Sun, 26 Apr 2009 05:07:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751979AbZDZJHH (ORCPT ); Sun, 26 Apr 2009 05:07:07 -0400 Received: from pfepa.post.tele.dk ([195.41.46.235]:37015 "EHLO pfepa.post.tele.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751868AbZDZJHF (ORCPT ); Sun, 26 Apr 2009 05:07:05 -0400 Date: Sun, 26 Apr 2009 11:09:06 +0200 From: Sam Ravnborg To: Tim Abbott Cc: Linus Torvalds , Linux kernel mailing list , Anders Kaseorg , Waseem Daher , Denys Vlasenko , Rusty Russell , Andi Kleen , "H. Peter Anvin" , Stephen Rothwell , Jeff Arnold , Andrew Morton , Jon Masters , Masami Hiramatsu , "Theodore Ts'o" , Nikanth Karthikesan , Arjan van de Ven , Paul Mundt , =?iso-8859-1?Q?Am=E9rico?= Wang Subject: Re: [PATCH v3 1/3] Make section names compatible with -ffunction-sections -fdata-sections Message-ID: <20090426090906.GA27809@uranus.ravnborg.org> References: <1240519774-20307-1-git-send-email-tabbott@mit.edu> <20090424172358.GA21946@uranus.ravnborg.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2567 Lines: 63 On Sat, Apr 25, 2009 at 10:10:38PM -0400, Tim Abbott wrote: > On Fri, 24 Apr 2009, Sam Ravnborg wrote: > > > This patch touches far too many files. > > We should try to work out a method so we are in better control > > of the section names, so renaming in the end is a simple patch > > touching only a few files. > > OK, I'm now planning to implement this approach. > > > > -.section .text.head, "ax" > > > +.section .text..head, "ax" > > > > Use __HEAD (from include/linux/init.h) > > Same goes for all other uses of .text.head. > > I notice that __HEAD uses .head.text, while some architectures use > .text.head. It looks like this is just an inconsistency across > architectures that will be removed as a consequence of this cleanup work > (no architecture uses both .head.text and .text.head). Correct - this is implied by the introduction of __HEAD. For users of the old naming schme (like i386) you need to adjust the linker script too. > One challenge with this approach is that many linker scripts use these > section names in more complex ways than just squashing HEAD_TEXT at the > start of the text section. For example, the the linker scripts for x86 > and ia64 have code like: > > .text.head : AT(ADDR(.text.head) - LOAD_OFFSET) { > _text = .; /* Text and read-only data */ > *(.text.head) > } :text = 0x9090 > > which can't user either the __HEAD macro (which is the full .section line) > or the HEAD_TEXT macro (which is the *(.head.text)). The simple way to deal wi8th this is to accept some duplication of naming in order to keep readability. So I suggest you to use: .head.text : AT(ADDR(.head.text) - LOAD_OFFSET) { _text = .; /* Text and read-only data */ HEAD_TEXT } :text = 0x9090 We need to be carefull about keeping some sort of readability of these linker macro files. I was not specific in my last mail about this - but I assume you have understood that the naming ".head.text" was selected so it is compatible wiht -ffunction-sections. In other words no need for any ugly ".." here. We should try to be as consistent as possible across architectures here so it is better to toach a few additiona files rather than adding macros and the like to accept there sub-optimal section naming. Sam -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/