From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: [PATCH v2 1/6] Add new macros for page-aligned data and bss sections. Date: Fri, 01 May 2009 09:33:13 -0700 Message-ID: <49FB2449.1010301@zytor.com> References: <1241121253-32341-1-git-send-email-tabbott@mit.edu> <1241121253-32341-2-git-send-email-tabbott@mit.edu> <20090501091848.GB18326@uranus.ravnborg.org> Reply-To: microblaze-uclinux-rVRm/Wmeqae7NGdpmJTKYQ@public.gmane.org Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: owner-microblaze-uclinux-FR6EJeJVuqfA6Z3fQjNZrN9u6TNh0Fb7@public.gmane.org List-Id: Content-Type: text/plain; charset="us-ascii" To: Tim Abbott Cc: Sam Ravnborg , Linux kernel mailing list , Anders Kaseorg , Waseem Daher , Denys Vlasenko , Jeff Arnold , Benjamin Herrenschmidt , Bryan Wu , Chris Zankel , Cyrill Gorcunov , David Howells , "David S. Miller" , dev-etrax-VrBV9hrLPhE@public.gmane.org, Geert Uytterhoeven , Greg Ungerer , Haavard Skinnemoen , Heiko Carstens , Helge Deller , Hirokazu Takata , Ingo Molnar , Jeff Dike Tim Abbott wrote: > On Fri, 1 May 2009, Sam Ravnborg wrote: > >> On Thu, Apr 30, 2009 at 03:54:08PM -0400, Tim Abbott wrote: >>> +#define __PAGE_ALIGNED_DATA .section ".data.page_aligned", "aw", @progbits >>> +#define __PAGE_ALIGNED_BSS .section ".bss.page_aligned", "aw", @nobits >> It is my understanding that the linker will automatically >> assume nobits for section names starting with .bss and likewise >> progbits for section names starting with .data - so we can leave them out? > > I believe that is correct. > ... but that doesn't mean it's the right thing to do. It's better to be fully explicit when macroizing this kind of stuff. This is part of why macroizing it is good: it means we end up with *one* place that determines this stuff, not some magic heuristics in the linker. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf. From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Fri, 01 May 2009 18:01:41 +0100 (BST) Received: from terminus.zytor.com ([198.137.202.10]:59971 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by ftp.linux-mips.org with ESMTP id S20027061AbZEARBf (ORCPT ); Fri, 1 May 2009 18:01:35 +0100 Received: from mail.hos.anvin.org (c-98-210-181-100.hsd1.ca.comcast.net [98.210.181.100]) (authenticated bits=0) by terminus.zytor.com (8.14.3/8.14.1) with ESMTP id n41GXTOq020302 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Fri, 1 May 2009 09:33:29 -0700 Received: from tazenda.hos.anvin.org (tazenda.hos.anvin.org [172.27.0.16]) by mail.hos.anvin.org (8.14.2/8.13.8) with ESMTP id n41GXS9r009009; Fri, 1 May 2009 09:33:28 -0700 Received: from tazenda.hos.anvin.org (localhost.localdomain [127.0.0.1]) by tazenda.hos.anvin.org (8.14.3/8.13.6) with ESMTP id n41GXD72013573; Fri, 1 May 2009 09:33:13 -0700 Message-ID: <49FB2449.1010301@zytor.com> Date: Fri, 01 May 2009 09:33:13 -0700 From: "H. Peter Anvin" User-Agent: Thunderbird 2.0.0.14 (X11/20080501) MIME-Version: 1.0 To: Tim Abbott CC: Sam Ravnborg , Linux kernel mailing list , Anders Kaseorg , Waseem Daher , Denys Vlasenko , Jeff Arnold , Benjamin Herrenschmidt , Bryan Wu , Chris Zankel , Cyrill Gorcunov , David Howells , "David S. Miller" , dev-etrax@axis.com, Geert Uytterhoeven , Greg Ungerer , Haavard Skinnemoen , Heiko Carstens , Helge Deller , Hirokazu Takata , Ingo Molnar , Jeff Dike , Jesper Nilsson , Kyle McMartin , Linus Torvalds , linux-alpha@vger.kernel.org, linux-ia64@vger.kernel.org, linux-m68k@vger.kernel.org, linux-mips@linux-mips.org, linux-parisc@vger.kernel.org, linuxppc-dev@ozlabs.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, Martin Schwidefsky , Michal Simek , microblaze-uclinux@itee.uq.edu.au, Mikael Starvik , Paul Mackerras , Paul Mundt , Ralf Baechle , Richard Henderson , Roman Zippel , Russell King , sparclinux@vger.kernel.org, Thomas Gleixner , Tony Luck , uclinux-dist-devel@blackfin.uclinux.org, user-mode-linux-devel@lists.sourceforge.net, Yoshinori Sato Subject: Re: [PATCH v2 1/6] Add new macros for page-aligned data and bss sections. References: <1241121253-32341-1-git-send-email-tabbott@mit.edu> <1241121253-32341-2-git-send-email-tabbott@mit.edu> <20090501091848.GB18326@uranus.ravnborg.org> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Virus-Scanned: ClamAV 0.94.2/9309/Thu Apr 30 20:55:03 2009 on terminus.zytor.com X-Virus-Status: Clean Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 22593 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: hpa@zytor.com Precedence: bulk X-list: linux-mips Tim Abbott wrote: > On Fri, 1 May 2009, Sam Ravnborg wrote: > >> On Thu, Apr 30, 2009 at 03:54:08PM -0400, Tim Abbott wrote: >>> +#define __PAGE_ALIGNED_DATA .section ".data.page_aligned", "aw", @progbits >>> +#define __PAGE_ALIGNED_BSS .section ".bss.page_aligned", "aw", @nobits >> It is my understanding that the linker will automatically >> assume nobits for section names starting with .bss and likewise >> progbits for section names starting with .data - so we can leave them out? > > I believe that is correct. > ... but that doesn't mean it's the right thing to do. It's better to be fully explicit when macroizing this kind of stuff. This is part of why macroizing it is good: it means we end up with *one* place that determines this stuff, not some magic heuristics in the linker. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf. From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: [PATCH v2 1/6] Add new macros for page-aligned data and bss sections. Date: Fri, 01 May 2009 09:33:13 -0700 Message-ID: <49FB2449.1010301@zytor.com> References: <1241121253-32341-1-git-send-email-tabbott@mit.edu> <1241121253-32341-2-git-send-email-tabbott@mit.edu> <20090501091848.GB18326@uranus.ravnborg.org> Reply-To: microblaze-uclinux-rVRm/Wmeqae7NGdpmJTKYQ@public.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: Sam Ravnborg , Linux kernel mailing list , Anders Kaseorg , Waseem Daher , Denys Vlasenko , Jeff Arnold , Benjamin Herrenschmidt , Bryan Wu , Chris Zankel , Cyrill Gorcunov , David Howells , "David S. Miller" , dev-etrax-VrBV9hrLPhE@public.gmane.org, Geert Uytterhoeven , Greg Ungerer , Haavard Skinnemoen , Heiko Carstens , Helge Deller , Hirokazu Takata , Ingo Molnar , Jeff Dike Return-path: In-Reply-To: List-ID: Tim Abbott wrote: > On Fri, 1 May 2009, Sam Ravnborg wrote: > >> On Thu, Apr 30, 2009 at 03:54:08PM -0400, Tim Abbott wrote: >>> +#define __PAGE_ALIGNED_DATA .section ".data.page_aligned", "aw", @progbits >>> +#define __PAGE_ALIGNED_BSS .section ".bss.page_aligned", "aw", @nobits >> It is my understanding that the linker will automatically >> assume nobits for section names starting with .bss and likewise >> progbits for section names starting with .data - so we can leave them out? > > I believe that is correct. > ... but that doesn't mean it's the right thing to do. It's better to be fully explicit when macroizing this kind of stuff. This is part of why macroizing it is good: it means we end up with *one* place that determines this stuff, not some magic heuristics in the linker. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from terminus.zytor.com (terminus.zytor.com [198.137.202.10]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 34DB4DDE19 for ; Sat, 2 May 2009 03:08:11 +1000 (EST) Message-ID: <49FB2449.1010301@zytor.com> Date: Fri, 01 May 2009 09:33:13 -0700 From: "H. Peter Anvin" MIME-Version: 1.0 To: Tim Abbott Subject: Re: [PATCH v2 1/6] Add new macros for page-aligned data and bss sections. References: <1241121253-32341-1-git-send-email-tabbott@mit.edu> <1241121253-32341-2-git-send-email-tabbott@mit.edu> <20090501091848.GB18326@uranus.ravnborg.org> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Cc: linux-mips@linux-mips.org, linux-m68k@vger.kernel.org, linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org, Denys Vlasenko , Heiko Carstens , linuxppc-dev@ozlabs.org, Paul Mackerras , Greg Ungerer , sparclinux@vger.kernel.org, Sam Ravnborg , Thomas Gleixner , linux-s390@vger.kernel.org, Jesper Nilsson , Yoshinori Sato , Helge Deller , Ingo Molnar , Geert Uytterhoeven , Russell King , user-mode-linux-devel@lists.sourceforge.net, microblaze-uclinux@itee.uq.edu.au, Jeff Dike , Jeff Arnold , dev-etrax@axis.com, Mikael Starvik , Cyrill Gorcunov , Michal Simek , Waseem Daher , Richard Henderson , Chris Zankel , Bryan Wu , Tony Luck , linux-parisc@vger.kernel.org, Haavard Skinnemoen , Hirokazu Takata , Linux kernel mailing list , Ralf Baechle , Anders Kaseorg , Kyle McMartin , Paul Mundt , linux-alpha@vger.kernel.org, Martin Schwidefsky , uclinux-dist-devel@blackfin.uclinux.org, Linus Torvalds , "David S. Miller" List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Tim Abbott wrote: > On Fri, 1 May 2009, Sam Ravnborg wrote: > >> On Thu, Apr 30, 2009 at 03:54:08PM -0400, Tim Abbott wrote: >>> +#define __PAGE_ALIGNED_DATA .section ".data.page_aligned", "aw", @progbits >>> +#define __PAGE_ALIGNED_BSS .section ".bss.page_aligned", "aw", @nobits >> It is my understanding that the linker will automatically >> assume nobits for section names starting with .bss and likewise >> progbits for section names starting with .data - so we can leave them out? > > I believe that is correct. > ... but that doesn't mean it's the right thing to do. It's better to be fully explicit when macroizing this kind of stuff. This is part of why macroizing it is good: it means we end up with *one* place that determines this stuff, not some magic heuristics in the linker. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.