From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gustavo Zacarias Date: Wed, 03 Nov 2010 22:25:46 -0300 Subject: [Buildroot] [Review] Add gcc 4.5.1 In-Reply-To: <201011032352.34417.yann.morin.1998@anciens.enib.fr> References: <1285020197-30269-1-git-send-email-Martin.Banky@gmail.com> <4CD1B69C.8020402@zacarias.com.ar> <201011032352.34417.yann.morin.1998@anciens.enib.fr> Message-ID: <4CD20B9A.9000008@zacarias.com.ar> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net 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.