From mboxrd@z Thu Jan  1 00:00:00 1970
From: Sam Ravnborg <sam@ravnborg.org>
Subject: Re: [PATCH v2 1/6] Add new macros for page-aligned data and bss sections.
Date: Fri, 1 May 2009 19:44:57 +0200
Message-ID: <20090501174457.GA26559@uranus.ravnborg.org>
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To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Tim Abbott <tabbott@MIT.EDU>, Linux kernel mailing list <linux-kernel@vger.kernel.org>, Anders Kaseorg <andersk@MIT.EDU>, Waseem Daher <wdaher@MIT.EDU>, Denys Vlasenko <vda.linux@googlemail.com>, Jeff Arnold <jbarnold@MIT.EDU>, Benjamin Herrenschmidt <benh@kernel.crashing.org>, Bryan Wu <cooloney@kernel.org>, Chris Zankel <chris@zankel.net>, Cyrill Gorcunov <gorcunov@openvz.org>, David Howells <dhowells@redhat.com>, "David S. Miller" <davem@davemloft.net>, dev-etrax@axis.com, Geert Uytterhoeven <geert@linux-m68k.org>, Greg Ungerer <gerg@uclinux.org>, Haavard Skinnemoen <hskinnemoen@atmel.com>, Heiko Carstens <heiko.carstens@de.ibm.com>, Helge Deller <deller@gmx.de>, Hirokazu Takata <takata@linux-m32r.org>, Ingo Molnar <mingo@redhat.com>, Jeff Dike <jdike@addtoit.com>, Jesper Nilsson <jesper.nilsson@axis.com>, Kyle McMartin <kyle@mcmartin.ca>, Linus Torvalds <torv>

On Fri, May 01, 2009 at 10:18:20AM -0700, H. Peter Anvin wrote:
> 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 @?
arm does not support it :-(
I recall it denote a comment in arm assembler.

I could do some magic to detect the ARM case but I'm reluctant to do so.
I could also ignore the arm issue for now as it is not used by arm,
but that strikes me as the wrong approach.


	Sam