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From: Gustavo Zacarias <gustavo@zacarias.com.ar>
To: buildroot@busybox.net
Subject: [Buildroot] [Review] Add gcc 4.5.1
Date: Wed, 03 Nov 2010 22:25:46 -0300	[thread overview]
Message-ID: <4CD20B9A.9000008@zacarias.com.ar> (raw)
In-Reply-To: <201011032352.34417.yann.morin.1998@anciens.enib.fr>

On 11/03/2010 07:52 PM, Yann E. MORIN wrote:

> Gustavo, All,
> 
> On Wednesday 03 November 2010 20:23:08 Gustavo Zacarias wrote:
>> Word of caution, gcc 4.5 isn't able to build good ARM kernels that can
>> load modules for versions <2.6.36 unless a patch is applied, see
>> https://bugzilla.kernel.org/show_bug.cgi?id=16310
> 
> From what I understand:
> - bug was introduced between 2.6.35-rc1 and -rc2: use the gcc option
>   only for powerpc
> - the mentioned gcc option was previously applied to all architectures
> - the bug has not been fixed on the 2.6.35.y tree
> - it was fixed during the 2.6.36 devel cycle
> 
> Which leads to the conclusion that:
> - 2.6.34 and prior         : not impacted
> - 2.6.35 and dot-releases  : impacted
> - 2.6.36 ( and above ;-) ) : not impacted
> 
> Sounds reasonable?
> 
> Regards,
> Yann E. MORIN.

See also... http://forums.arm.com/index.php?showtopic=8122
It seems gcc 4.5.x emits R_ARM_REL32 relocations by default unless
-fno-dwarf2-cfi-asm is passed as a build option and the ARM kernel
doesn't handle it (see arch/arm/include/asm/elf.h and
arch/arm/kernel/module.c).
I've Considered patching gcc to disable it by default in buildroot but
since it's the kernel at fault i don't see the value in it yet, we'd
just be punishing userland in the process too.
I didn't try with <2.6.35 myself, i'll give it a shot tomorrow to see
how extended this problem might be (bug report talks about 4.4.x rather
than 4.5.x and i've never hit the issue it with 4.4.x).
Regards.

  reply	other threads:[~2010-11-04  1:25 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-09-20 22:03 [Buildroot] [Review] Add gcc 4.5.1 Martin Banky
2010-09-20 22:03 ` [Buildroot] [PATCH 1/3] dbus: bump to 1.4.0 Martin Banky
2010-09-20 22:03 ` [Buildroot] [PATCH 2/3] m4: bump to 1.4.15 Martin Banky
2010-09-20 22:03 ` [Buildroot] [PATCH 3/3] Added gcc 4.5.1 to buildroot Martin Banky
2010-11-03 19:23 ` [Buildroot] [Review] Add gcc 4.5.1 Gustavo Zacarias
2010-11-03 22:52   ` Yann E. MORIN
2010-11-04  1:25     ` Gustavo Zacarias [this message]
2010-11-04 23:05   ` Peter Korsgaard

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