This is the mail archive of the
binutils@sourceware.org
mailing list for the binutils project.
Re: current binutils trunk fails to build bootable kernel image for some configurations
- From: Sam Ravnborg <sam at ravnborg dot org>
- To: Matthias Klose <doko at ubuntu dot com>, binutils <binutils at sourceware dot org>, Bastian Blank <waldi at debian dot org>, Linus Torvalds <torvalds at linux-foundation dot org>, linux-kernel at vger dot kernel dot org, Kiko Piris <kernel at pirispons dot net>, Damien Wyart <damien dot wyart at free dot fr>, Greg KH <gregkh at suse dot de>, Wolfgang Walter <wolfgang dot walter at stwm dot de>
- Date: Thu, 23 Jul 2009 07:05:22 +0200
- Subject: Re: current binutils trunk fails to build bootable kernel image for some configurations
- References: <4A6746B9.9010603@ubuntu.com> <20090723004939.GF13233@bubble.grove.modra.org>
On Thu, Jul 23, 2009 at 10:19:39AM +0930, Alan Modra wrote:
> On Wed, Jul 22, 2009 at 01:04:57PM -0400, Matthias Klose wrote:
> > this was reported as http://bugs.debian.org/537389, I currently don't
> > have much more information, besides that one of the Debian kernel
> > maintainers did identify
> >
> > 2009-07-11 Alan Modra <amodra@bigpond.net.au>
> >
> > * ldlang.c (insert_os_after): Don't tie assignments to non-alloc
> > output sections.
> >
> > this patch as the one causing the wrongly built kernel. However I don't
> > see this checkin mentioned on the ML.
>
> The discussion happened on bug-binutils.
> http://lists.gnu.org/archive/html/bug-binutils/2009-07/msg00067.html
>
> > Bastian Blank did check that the
> > problem goes away with a binutils build from trunk and this patch
> > reverted. Some more analysis in http://lkml.org/lkml/2009/7/21/400
>
> The biggest problem is that the kernel linker script doesn't mention
> all sections, which means ld must choose a place for the unmentioned
> sections (orphans). Sometimes ld's placement isn't how a naive
> programmer would expect.
>
> In this case:
>
> . = ALIGN(PAGE_SIZE);
> .data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) {
>
> ld stuck an orphan section between the two statements. Which meant
> that the start of .data_nosave is not aligned (and since the end is
> aligned by following statements, it means that .data_nosave also has
> padding inserted). It would be more robust to write:
>
> .data_nosave ALIGN(PAGE_SIZE) : AT(ADDR(.data_nosave) - LOAD_OFFSET) {
Do you recall when this started to be supported?
I think I tried this and it failed - but I may be wrong here.
Also - do there exist an option to tell what sections has not been
covered by a linker script?
Sam