From: Dmitry Torokhov <dtor@vmware.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
David Miller <davem@davemloft.net>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Rusty Russell <rusty@rustcorp.com.au>,
Linux/m68k <linux-m68k@vger.kernel.org>,
Linux-Arch <linux-arch@vger.kernel.org>
Subject: Re: [PATCH 1/3] module: deal with alignment issues in built-in module versions
Date: Thu, 17 Feb 2011 09:31:36 -0800 [thread overview]
Message-ID: <20110217173136.GA28486@dtor-ws.eng.vmware.com> (raw)
In-Reply-To: <AANLkTim_BL_Cw=X0iuatgw1F4n50CyXv0uqx9n=5=Bq+@mail.gmail.com>
On Thu, Feb 17, 2011 at 09:24:58AM -0800, Linus Torvalds wrote:
> On Mon, Feb 7, 2011 at 4:02 PM, Dmitry Torokhov <dtor@vmware.com> wrote:
> >
> > Moreover, as DaveM said, we can't reliably put structures into
> > independent objects, put them into a special section, and then expect
> > array access over them (via the section boundaries) after linking the
> > objects together to just "work" due to variable alignment choices in
> > different situations.
>
> Why not?
>
> That's what we normally do. Just align the "__modver", and you should
> be all good. What's the problem?
From what I understand __attribute__ ((aligned(x))) only guarantees
minimum alignment, not exact (gapless) alignment. GCC seems to lay out
pointers in the section without gaps on all arches that we have.
Thanks.
--
Dmitry
WARNING: multiple messages have this Message-ID (diff)
From: Dmitry Torokhov <dtor@vmware.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
David Miller <davem@davemloft.net>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Rusty Russell <rusty@rustcorp.com.au>,
Linux/m68k <linux-m68k@vger.kernel.org>,
Linux-Arch <linux-arch@vger.kernel.org>
Subject: Re: [PATCH 1/3] module: deal with alignment issues in built-in module versions
Date: Thu, 17 Feb 2011 09:31:36 -0800 [thread overview]
Message-ID: <20110217173136.GA28486@dtor-ws.eng.vmware.com> (raw)
In-Reply-To: <AANLkTim_BL_Cw=X0iuatgw1F4n50CyXv0uqx9n=5=Bq+@mail.gmail.com>
On Thu, Feb 17, 2011 at 09:24:58AM -0800, Linus Torvalds wrote:
> On Mon, Feb 7, 2011 at 4:02 PM, Dmitry Torokhov <dtor@vmware.com> wrote:
> >
> > Moreover, as DaveM said, we can't reliably put structures into
> > independent objects, put them into a special section, and then expect
> > array access over them (via the section boundaries) after linking the
> > objects together to just "work" due to variable alignment choices in
> > different situations.
>
> Why not?
>
> That's what we normally do. Just align the "__modver", and you should
> be all good. What's the problem?
>From what I understand __attribute__ ((aligned(x))) only guarantees
minimum alignment, not exact (gapless) alignment. GCC seems to lay out
pointers in the section without gaps on all arches that we have.
Thanks.
--
Dmitry
next prev parent reply other threads:[~2011-02-17 17:31 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-08 0:02 [PATCH 1/3] module: deal with alignment issues in built-in module versions Dmitry Torokhov
2011-02-08 0:02 ` [PATCH 2/3] module: deal with alignment issues in built-in module parameters Dmitry Torokhov
2011-02-08 0:02 ` [PATCH 3/3] module: do not hide __modver_version_show declaration behind ifdef Dmitry Torokhov
2011-02-08 21:12 ` [PATCH 1/3] module: deal with alignment issues in built-in module versions Geert Uytterhoeven
2011-02-08 21:12 ` Geert Uytterhoeven
2011-02-17 12:43 ` Geert Uytterhoeven
2011-02-17 12:43 ` Geert Uytterhoeven
2011-02-11 22:03 ` [PATCH v2] module: deal with alignment issues in built-in module parameters Dmitry Torokhov
2011-02-11 22:03 ` Dmitry Torokhov
2011-02-13 23:04 ` Rusty Russell
2011-02-17 17:24 ` [PATCH 1/3] module: deal with alignment issues in built-in module versions Linus Torvalds
2011-02-17 17:31 ` Dmitry Torokhov [this message]
2011-02-17 17:31 ` Dmitry Torokhov
2011-02-17 17:45 ` Linus Torvalds
2011-02-17 18:00 ` Dmitry Torokhov
2011-02-17 18:06 ` Linus Torvalds
2011-02-17 21:01 ` David Miller
2011-02-17 21:11 ` Linus Torvalds
2011-02-17 21:17 ` David Miller
2011-02-17 21:54 ` Linus Torvalds
2011-02-17 22:01 ` David Miller
2011-02-17 22:19 ` Dmitry Torokhov
2011-02-17 22:23 ` David Miller
2011-02-17 22:48 ` Linus Torvalds
2011-02-17 23:08 ` Linus Torvalds
2011-02-17 23:19 ` David Miller
2011-02-19 0:14 ` Benjamin Herrenschmidt
2011-02-21 4:00 ` Rusty Russell
2011-02-21 7:38 ` Geert Uytterhoeven
2011-02-21 7:49 ` Dmitry Torokhov
2011-02-21 7:49 ` Dmitry Torokhov
2011-02-21 13:25 ` Geert Uytterhoeven
2011-02-22 1:58 ` Benjamin Herrenschmidt
2011-02-22 2:03 ` Linus Torvalds
2011-02-22 7:02 ` Dmitry Torokhov
2011-02-22 7:02 ` Dmitry Torokhov
2011-02-22 17:08 ` Jesper Nilsson
2011-02-22 20:47 ` Linus Torvalds
2011-02-23 15:00 ` Jesper Nilsson
2011-02-23 15:00 ` Jesper Nilsson
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