[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <AANLkTilU133SjYfKGvUiQQ8v-CiecRYmKtH2tzAxL-3u@mail.gmail.com>
Date: Wed, 26 May 2010 08:59:26 +0200
From: Geert Uytterhoeven <geert@...ux-m68k.org>
To: Jie Zhang <jie@...esourcery.com>
Cc: Mike Frysinger <vapier.adi@...il.com>,
Paul Mundt <lethal@...ux-sh.org>,
Mike Frysinger <vapier@...too.org>, uclinux-dev@...inux.org,
David Howells <dhowells@...hat.com>,
David McCullough <davidm@...pgear.com>,
Greg Ungerer <gerg@...inux.org>,
uclinux-dist-devel@...ckfin.uclinux.org,
microblaze-uclinux@...e.uq.edu.au, Michal Simek <monstr@...str.eu>,
linux-m32r@...linux-m32r.org,
Hirokazu Takata <takata@...ux-m32r.org>,
linux-kernel@...r.kernel.org,
Yoshinori Sato <ysato@...rs.sourceforge.jp>
Subject: Re: [PATCH] FLAT: allow arches to declare a larger alignment than the
slab
On Wed, May 26, 2010 at 04:23, Jie Zhang <jie@...esourcery.com> wrote:
> On 05/26/2010 07:17 AM, Mike Frysinger wrote:
>>
>> i do not believe that is the reason for this, but unfortunately Jie is
>> about the only one atm who knows the inner details as for why shared
>> FLAT libraries requires 0x20 rather than just 0x4 alignment. i do
>> know that there are some gcc fortran tests that fail otherwise.
>> hopefully he can remember details ;).
>>
> I encountered this issue when investigating some GCC test failures when
> using FLAT. I don't remember if they were in GCC Fortran testsuite. Some
> variables in those test cases were required to be aligned at a large
> boundary, for example 16-byte. I found 0x20 was a reasonably large alignment
> to fix all such failures in GCC testsuite.
I'm no FLAT expert (except for the AmigaOS HUNK loader :-), but isn't
the core of the
issue that alignment requirements in the object file are no longer
fulfilled after loading,
as a FLAT segment in memory is just allocated using kmalloc(), which may now
return 4-byte aligned blocks?
>From looking at <linux/flat.h>, it looks like the FLAT binary format
doesn't contain any
alignment information? So if I put __attribute__((aligned(4096))) in a
file, there's still
no guarantee it will actually be in memory at a 4Ki-aligned address?
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists