Mailinglist Archive: opensuse-kernel (59 mails)

[Michael Matz <matz@xxxxxxx>]

Hi,

On Thu, 25 Jun 2009, Jeff Mahoney wrote:

> I tested it by changing the INITCALLS macro in 
> include/asm-generic/vmlinux.lds.h to issue individual sections. I had to 
> add initcalls.{start,end} sections to contain the pointers describing 
> the boundaries of the initcalls too.

Yes.

> > > Would the initcall sections in the module properly merge into them? 
> > > Or are we already too late and the relocation records are lost?
> >
> > ... because this is not the case, the modules are .o files, not fully 
> > linked, so all relocations are still there.
>
> In the modules, yes. I was wondering about the static image.

Um, wait.  You really want to link the module lump together with the 
static image?  That's not going to work easily (or at all) as the static 
image is fully linked and doesn't contain all necessary relocations 
anymore to move around its sections (which happens if you insert stuff 
into the existing ones).  So, instead of amending the existing .text 
section in vmlinux (to contain the merged .text's from the modules) you 
would have to put this blob into an extra .text2 (for instance) behind all 
other current sections of vmlinux.  You'd have to do that for all 
sections, essentially being back at attaching the blob simply to the end 
of vmlinux (with the change that you only have one set of ELF section 
headers, instead of two, but that's minor).

In my mind that module lump would not be linked with the static image, but 
would rather be sort of a mega-module that is loaded implicitely.  It 
would "somehow" be tacked at the end of vmlinux as blob and then loaded 
with a only mildly extended module loader (basically everything as now, 
just that you have multiple this_module sections, and with the difference 
that the initcall order is split and changed)

> I have a script that parses the existing section headers and generates a 
> script with the proper alignment (I hope). Whether it actually works or 
> not, I can't tell yet, since I run into this: ld: 
> vmlinux(.text.head+0xc020000c): reloc against `boot_gdt_descr': error 2

Maybe that's a result of vmlinux already fully linked.  Hmm... wasn't it 
once the case that during building the kernel initially only a merged .o 
file for everything was generated and that one then again got fully 
linked?  vmlinux.o or something... you could use that.

> I'm not sure what's causing that yet.

Seems to be an internal linker error.  What's output of 'readelf -rsW 
vmlinux | grep boot_gdt_descr' (i.e. what type of reloc and symbol is 
this)?


Ciao,
Michael.
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