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 10:18:20 -0700 Message-ID: <49FB2EDC.9050300@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> <49FB2449.1010301@zytor.com> <20090501171717.GA26401@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: <20090501171717.GA26401-QabhHTsIXMSnlFQ6Q1D1Y0B+6BGkLq7r@public.gmane.org> Sender: owner-microblaze-uclinux-FR6EJeJVuqfA6Z3fQjNZrN9u6TNh0Fb7@public.gmane.org List-Id: Content-Type: text/plain; charset="us-ascii" To: Sam Ravnborg Cc: Tim Abbott , 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 Sam Ravnborg wrote: > On Fri, May 01, 2009 at 09:33:13AM -0700, H. Peter Anvin wrote: >> 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. > > Do you know if we can use % in place of @? > I could see that gas supports both - at least in trunk in cvs. > I think it might depend on the architecture(!)... but it would definitely have to be an issue with testing a bunch of different versions. What's wrong with @? -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 18:29:58 +0100 (BST) Received: from terminus.zytor.com ([198.137.202.10]:43449 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by ftp.linux-mips.org with ESMTP id S20027183AbZEAR3v (ORCPT ); Fri, 1 May 2009 18:29:51 +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 n41HIPSU028658 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Fri, 1 May 2009 10:18:25 -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 n41HIOqU009097; Fri, 1 May 2009 10:18:24 -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 n41HIK58014054; Fri, 1 May 2009 10:18:22 -0700 Message-ID: <49FB2EDC.9050300@zytor.com> Date: Fri, 01 May 2009 10:18:20 -0700 From: "H. Peter Anvin" User-Agent: Thunderbird 2.0.0.14 (X11/20080501) MIME-Version: 1.0 To: Sam Ravnborg CC: Tim Abbott , 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> <49FB2449.1010301@zytor.com> <20090501171717.GA26401@uranus.ravnborg.org> In-Reply-To: <20090501171717.GA26401@uranus.ravnborg.org> 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: 22595 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 Sam Ravnborg wrote: > On Fri, May 01, 2009 at 09:33:13AM -0700, H. Peter Anvin wrote: >> 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. > > Do you know if we can use % in place of @? > I could see that gas supports both - at least in trunk in cvs. > I think it might depend on the architecture(!)... but it would definitely have to be an issue with testing a bunch of different versions. What's wrong with @? -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 10:18:20 -0700 Message-ID: <49FB2EDC.9050300@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> <49FB2449.1010301@zytor.com> <20090501171717.GA26401@uranus.ravnborg.org> Reply-To: microblaze-uclinux-rVRm/Wmeqae7NGdpmJTKYQ@public.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: Tim Abbott , 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: <20090501171717.GA26401-QabhHTsIXMSnlFQ6Q1D1Y0B+6BGkLq7r@public.gmane.org> List-ID: Sam Ravnborg wrote: > On Fri, May 01, 2009 at 09:33:13AM -0700, H. Peter Anvin wrote: >> 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. > > Do you know if we can use % in place of @? > I could see that gas supports both - at least in trunk in cvs. > I think it might depend on the architecture(!)... but it would definitely have to be an issue with testing a bunch of different versions. What's wrong with @? -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 4F5BCDDE1B for ; Sat, 2 May 2009 03:38:31 +1000 (EST) Message-ID: <49FB2EDC.9050300@zytor.com> Date: Fri, 01 May 2009 10:18:20 -0700 From: "H. Peter Anvin" MIME-Version: 1.0 To: Sam Ravnborg 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> <49FB2449.1010301@zytor.com> <20090501171717.GA26401@uranus.ravnborg.org> In-Reply-To: <20090501171717.GA26401@uranus.ravnborg.org> 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 , Tim Abbott , Heiko Carstens , linuxppc-dev@ozlabs.org, Paul Mackerras , Greg Ungerer , sparclinux@vger.kernel.org, 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: , Sam Ravnborg wrote: > On Fri, May 01, 2009 at 09:33:13AM -0700, H. Peter Anvin wrote: >> 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. > > Do you know if we can use % in place of @? > I could see that gas supports both - at least in trunk in cvs. > I think it might depend on the architecture(!)... but it would definitely have to be an issue with testing a bunch of different versions. What's wrong with @? -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.