[PATCH] restore export of handle_mm_fault for Mac on Linux

[Gaudenz Steinlin]

Hi

The kernel modules for Mac on Linux (MOL) need handle_mm_fault.
MOL is a GPL licensed virtual machine to run MacOS(X) on PPC Linux.

The export for handle_mm_fault was removed with commit
41f9dc5c871600f53c8912b2975971d2a11c1c25.

Previously the export has been present since handle_mm_fault was
converted from an inline function to a non-inline one. See the thread
starting at http://marc.info/?l=linux-kernel&m=112327941709177&w=2 for
the initial discussion.

With commit 67207b9664a8d603138ef1556141e6d0a102bea7 the export was
moved from arch/ppc/kernel/ppc_ksyms.c to mm/memory.c. In this patch the
explanatory comment /* For MOL */ got lost. Thus to export was not moved
back to it's original place when it was no longer needed for spufs.

The attached patch restores the symbol export (GPL only) in it's
original place. Please consider applying it because this fixes a
regression for MOL.

Thanks

Gaudenz

P.S.: Please CC me and the corresponding Debian bug report on any
replies.

[Christoph Hellwig]

Post by Gaudenz Steinlin
Hi
The kernel modules for Mac on Linux (MOL) need handle_mm_fault.
MOL is a GPL licensed virtual machine to run MacOS(X) on PPC Linux.

Has been rejected a few times. An now that we actually have kvm
for powerpc in tree MOL should just merge with that project and
do the right things in tree instead of beeing a really hacky
module subverting the VM.

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[Paul Mackerras]

Post by Christoph Hellwig

Post by Gaudenz Steinlin
Hi
The kernel modules for Mac on Linux (MOL) need handle_mm_fault.
MOL is a GPL licensed virtual machine to run MacOS(X) on PPC Linux.

Has been rejected a few times. An now that we actually have kvm
for powerpc in tree MOL should just merge with that project and
do the right things in tree instead of beeing a really hacky
module subverting the VM.

We don't have KVM for the "classic" 32-bit PowerPC processors, only
for the 44x family. And doing KVM for the classic 32-bit processors
would probably involve just as much hackery as MOL. :)

Paul.
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[Christoph Hellwig]

Post by Paul Mackerras

Post by Christoph Hellwig
Has been rejected a few times. An now that we actually have kvm
for powerpc in tree MOL should just merge with that project and
do the right things in tree instead of beeing a really hacky
module subverting the VM.

We don't have KVM for the "classic" 32-bit PowerPC processors, only
for the 44x family. And doing KVM for the classic 32-bit processors
would probably involve just as much hackery as MOL. :)

I don't think so. Doing it properly in-tree will mean that it is

a) properly reviewed
b) means we can do the major VM bits in the kernel without these
really stupid exports

Have you looked at MOL recently? It's more than disgusting.

And in addition to these issue we do of course as policy not add
random hooks in the kernel tree for out of tree stuff. Especially
for hacks like this that don't even have the intention to get merged.
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[Gaudenz Steinlin]

Post by Christoph Hellwig

Post by Paul Mackerras

Post by Christoph Hellwig
Has been rejected a few times. An now that we actually have kvm
for powerpc in tree MOL should just merge with that project and
do the right things in tree instead of beeing a really hacky
module subverting the VM.

We don't have KVM for the "classic" 32-bit PowerPC processors, only
for the 44x family. And doing KVM for the classic 32-bit processors
would probably involve just as much hackery as MOL. :)

I don't think so. Doing it properly in-tree will mean that it is
a) properly reviewed
b) means we can do the major VM bits in the kernel without these
really stupid exports
Have you looked at MOL recently? It's more than disgusting.
And in addition to these issue we do of course as policy not add
random hooks in the kernel tree for out of tree stuff. Especially
for hacks like this that don't even have the intention to get merged.

This is not true anymore. See my other message to this thread. Joseph
Jezak is working on a mergeable module.

Gaudenz

[Alan Cox]

On Wed, 18 Jun 2008 12:14:02 +0200

Post by Gaudenz Steinlin
Hi
The kernel modules for Mac on Linux (MOL) need handle_mm_fault.
MOL is a GPL licensed virtual machine to run MacOS(X) on PPC Linux.
The export for handle_mm_fault was removed with commit
41f9dc5c871600f53c8912b2975971d2a11c1c25.

This sort of thing is going to happen if modules hide out of tree. If MOL
is GPL why isn't it getting submitted to the kernel tree - other
virtualisation subsystems such as KVM are in tree ?
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[Gaudenz Steinlin]

Post by Alan Cox
On Wed, 18 Jun 2008 12:14:02 +0200

Post by Gaudenz Steinlin
Hi
The kernel modules for Mac on Linux (MOL) need handle_mm_fault.
MOL is a GPL licensed virtual machine to run MacOS(X) on PPC Linux.
The export for handle_mm_fault was removed with commit
41f9dc5c871600f53c8912b2975971d2a11c1c25.

This sort of thing is going to happen if modules hide out of tree. If MOL
is GPL why isn't it getting submitted to the kernel tree - other
virtualisation subsystems such as KVM are in tree ?

There is an effort underway to bring the MOL kernel modules into
a mergeable form. But it's not there yet. Joseph Jezak, the MOl main
developer nowdays is working on it. So MOL no longer want's to hide out
of tree. It just needs some more time.

What I'm asking for is to get the export back, that as far as I can see
was removed accidentialy and that was there before specially for MOL.

It's true that this has been requested before just after the symbol was
removed and Christoph NAKed it then. But if I remember correctly people
were not aware that this symbol has been exported specifically for MOL
before back then.

Gaudenz

[Christoph Hellwig]

Post by Gaudenz Steinlin
There is an effort underway to bring the MOL kernel modules into
a mergeable form. But it's not there yet. Joseph Jezak, the MOl main
developer nowdays is working on it. So MOL no longer want's to hide out
of tree. It just needs some more time.

It would be useful if you could send some status-updates to lkml and
the kvm list.

Post by Gaudenz Steinlin
What I'm asking for is to get the export back, that as far as I can see
was removed accidentialy and that was there before specially for MOL.

It was removed intentionally.

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[Pekka Enberg]

Post by Christoph Hellwig

Post by Gaudenz Steinlin
There is an effort underway to bring the MOL kernel modules into
a mergeable form. But it's not there yet. Joseph Jezak, the MOl main
developer nowdays is working on it. So MOL no longer want's to hide out
of tree. It just needs some more time.

It would be useful if you could send some status-updates to lkml and
the kvm list.

And why not submit MOL to the new linux-staging tree?
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[Greg KH]

Post by Pekka Enberg

Post by Christoph Hellwig

Post by Gaudenz Steinlin
There is an effort underway to bring the MOL kernel modules into
a mergeable form. But it's not there yet. Joseph Jezak, the MOl main
developer nowdays is working on it. So MOL no longer want's to hide out
of tree. It just needs some more time.

It would be useful if you could send some status-updates to lkml and
the kvm list.

And why not submit MOL to the new linux-staging tree?

That sounds good to me, send them over when you have something that
builds and looks semi-sane :)

thanks,

greg k-h
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