rela sections in vmlinux

rela sections in vmlinux

[Ruslan Kuprieiev]

Hi!

I'm trying to figure out how CONFIG_RELOCATABLE works and one of the things
that I've noticed is that vmlinux itself doesn't have any rela sections, 
which is
confusing for me considering the name of the option. I did read the 
patches that
introduced this option but it is still not clear to me how exactly it 
works and why
there are no relocations left in the vmlinux. Could you please give me a 
hint on
why it happens and point me where to read more?

I also see that vmlinux.o has all the rela sections I'm looking for(as 
an object file
should =)), so it raises another question: Is it possible to make 
vmlinux keep that
rela sections? I also went through makefiles but couldn't figure out 
where to
make a proper change to achieve that.

I'm using default 3.10.0-229.20.1.el7.x86_64 centos7 kernel with 
CONFIG_RELOCATABLE
enabled.

Thanks,
Ruslan

Re: rela sections in vmlinux

[Ruslan Kuprieiev]

Hi All,

Just wanted to answer my own question.

The problem was that I forgot to add --emit-relocs to my own script and
that's why I didn't find any rela sections in vmlinux. After adding proper
ld options everything started to make sense =).

Thanks,
Ruslan

On 03/06/2016 11:04 PM, Ruslan Kuprieiev wrote:
> Hi!
>
> I'm trying to figure out how CONFIG_RELOCATABLE works and one of the 
> things
> that I've noticed is that vmlinux itself doesn't have any rela 
> sections, which is
> confusing for me considering the name of the option. I did read the 
> patches that
> introduced this option but it is still not clear to me how exactly it 
> works and why
> there are no relocations left in the vmlinux. Could you please give me 
> a hint on
> why it happens and point me where to read more?
>
> I also see that vmlinux.o has all the rela sections I'm looking for(as 
> an object file
> should =)), so it raises another question: Is it possible to make 
> vmlinux keep that
> rela sections? I also went through makefiles but couldn't figure out 
> where to
> make a proper change to achieve that.
>
> I'm using default 3.10.0-229.20.1.el7.x86_64 centos7 kernel with 
> CONFIG_RELOCATABLE
> enabled.
>
> Thanks,
> Ruslan