2.6VMM, uClinux, & Comedi

2.6VMM, uClinux, & Comedi

[NZG]

I managed to successfully cross-compile Comedi for the Coldfire uClinux 2.6, 
however it has several unresolved symbols when I try to load it.

comedi: Unknown symbol pgd_offset_k
comedi: Unknown symbol pmd_none
comedi: Unknown symbol remap_page_range
comedi: Unknown symbol pte_present
comedi: Unknown symbol pte_offset_kernel
comedi: Unknown symbol VMALLOC_VMADDR
comedi: Unknown symbol pte_page

Apparently uClinux isn't implementing these paged memory functions,which
kind of makes sense, but I'm a little fuzzy on what the nommu code is
supposed to be doing exactly, and I couldn't find any documentation on what 
these functions are doing in the vanilla 2.6 kernel.
Has anyone else been down this road before?
I found Mel Gorman's Thesis on the 2.4 mm functions, but I couldn't find most 
of these symbols in it.
It's looking like the 2.6 mm stuff is still pretty undocumented, any links to 
documentation (or short text explanations)would be appreciated. 

thx.
NZG.

Re: 2.6VMM, uClinux, & Comedi

[Bernd Porr]

Looks quite promising. I would like to run comedi on a blackfin stamp. 
Please keep me in the loop.

/Bernd

www:    http://www.berndporr.me.uk/
         http://www.linux-usb-daq.co.uk/
Mobile: +44 (0)7840 340069
Work:   +44 (0)141 330 5237
         University of Glasgow
         Department of Electronics & Electrical Engineering
         Room 519, Rankine Building, Oakfield Avenue,
         Glasgow, G12 8LT


NZG wrote:
> I managed to successfully cross-compile Comedi for the Coldfire uClinux 2.6, 
> however it has several unresolved symbols when I try to load it.
> 
> comedi: Unknown symbol pgd_offset_k
> comedi: Unknown symbol pmd_none
> comedi: Unknown symbol remap_page_range
> comedi: Unknown symbol pte_present
> comedi: Unknown symbol pte_offset_kernel
> comedi: Unknown symbol VMALLOC_VMADDR
> comedi: Unknown symbol pte_page
> 
> Apparently uClinux isn't implementing these paged memory functions,which
> kind of makes sense, but I'm a little fuzzy on what the nommu code is
> supposed to be doing exactly, and I couldn't find any documentation on what 
> these functions are doing in the vanilla 2.6 kernel.
> Has anyone else been down this road before?
> I found Mel Gorman's Thesis on the 2.4 mm functions, but I couldn't find most 
> of these symbols in it.
> It's looking like the 2.6 mm stuff is still pretty undocumented, any links to 
> documentation (or short text explanations)would be appreciated. 
> 
> thx.
> NZG.
> 
> _______________________________________________
> comedi mailing list
> comedi@comedi.org
> https://cvs.comedi.org/cgi-bin/mailman/listinfo/comedi

Re: 2.6VMM, uClinux, & Comedi

[Ian Abbott]

On 01/08/05 14:17, NZG wrote:
> I managed to successfully cross-compile Comedi for the Coldfire uClinux 2.6, 
> however it has several unresolved symbols when I try to load it.
> 
> comedi: Unknown symbol pgd_offset_k
> comedi: Unknown symbol pmd_none
> comedi: Unknown symbol remap_page_range
> comedi: Unknown symbol pte_present
> comedi: Unknown symbol pte_offset_kernel
> comedi: Unknown symbol VMALLOC_VMADDR
> comedi: Unknown symbol pte_page

It's probably coming to grief in Comedi's Linux compatibility headers 
somewhere, but as this stuff has changed a few times, which version of 
Comedi and which kernel version are you using exactly?

-- 
-=( Ian Abbott @ MEV Ltd.    E-mail: <abbotti@mev.co.uk>        )=-
-=( Tel: +44 (0)161 477 1898   FAX: +44 (0)161 718 3587         )=-

Re: 2.6VMM, uClinux, & Comedi

[NZG]

I'm running comedi-0.7.70, but the issue is seems be be coming from the fact 
that I'm using a nommu arch.
grepping through my arch and include/asm, these symbols are indeed not 
defined.
This makes sense because uClinux has no true virtual memory, vmalloc is just a 
wrapper for kmalloc.
The implementation of these functions is probably trivial, but It's taking me 
a bit since I didn't really understand the VM code before (now I have a small 
inkling)
I'll get there, I'm just surprised this hasn't been attempted before.

NZG.

On Tuesday 02 August 2005 08:27, Ian Abbott wrote:
> On 01/08/05 14:17, NZG wrote:
> > I managed to successfully cross-compile Comedi for the Coldfire uClinux
> > 2.6, however it has several unresolved symbols when I try to load it.
> >
> > comedi: Unknown symbol pgd_offset_k
> > comedi: Unknown symbol pmd_none
> > comedi: Unknown symbol remap_page_range
> > comedi: Unknown symbol pte_present
> > comedi: Unknown symbol pte_offset_kernel
> > comedi: Unknown symbol VMALLOC_VMADDR
> > comedi: Unknown symbol pte_page
>
> It's probably coming to grief in Comedi's Linux compatibility headers
> somewhere, but as this stuff has changed a few times, which version of
> Comedi and which kernel version are you using exactly?

Re: 2.6VMM, uClinux, & Comedi

[Ian Abbott]

On 02/08/05 22:12, NZG wrote:
> On Tuesday 02 August 2005 08:27, Ian Abbott wrote:
> 
>>On 01/08/05 14:17, NZG wrote:
>>
>>>I managed to successfully cross-compile Comedi for the Coldfire uClinux
>>>2.6, however it has several unresolved symbols when I try to load it.
>>>
>>>comedi: Unknown symbol pgd_offset_k
>>>comedi: Unknown symbol pmd_none
>>>comedi: Unknown symbol remap_page_range
>>>comedi: Unknown symbol pte_present
>>>comedi: Unknown symbol pte_offset_kernel
>>>comedi: Unknown symbol VMALLOC_VMADDR
>>>comedi: Unknown symbol pte_page
>>
>>It's probably coming to grief in Comedi's Linux compatibility headers
>>somewhere, but as this stuff has changed a few times, which version of
>>Comedi and which kernel version are you using exactly?

> I'm running comedi-0.7.70, but the issue is seems be be coming from the fact 
> that I'm using a nommu arch.

You didn't say what kernel version you were using, but it appears to be 
2.6.9 or less.  Maybe some of the portability issues have been resolved 
in 2.6.12-uc (though probably not all of them).

> The implementation of these functions is probably trivial, but It's taking me 
> a bit since I didn't really understand the VM code before (now I have a small 
> inkling)

The uClinux folks could probably help you there.

> I'll get there, I'm just surprised this hasn't been attempted before.

So you're a pioneer!  Good luck!

-- 
-=( Ian Abbott @ MEV Ltd.    E-mail: <abbotti@mev.co.uk>        )=-
-=( Tel: +44 (0)161 477 1898   FAX: +44 (0)161 718 3587         )=-