RE: [5/5] move_pages: 32bit support (i386,x86_64 and ia64)

RE: [5/5] move_pages: 32bit support (i386,x86_64 and ia64)

[Luck, Tony]

> 2. There is a whole range of syscalls missing for ia64 that I basically
>   interpolated from elsewhere.

I've been thinking of dropping CONFIG_IA32_SUPPORT completely from ia64.
I've heard no complaints that new syscalls are not being added to the
ia32 compat side ... which is an indication that people are not
actively using this.  Some OSDs have been building with this
turned off for a while now (perhaps in preparation for "Montecito"
which no longer has h/w support for the x86 instruction set, or
perhaps because it represnts a huge block of lightly/barely tested
code that will have its share of support issues).

I suppose I should do this by adding an entry to
 Documentation/feature-removal-schedule.txt

Any thoughts on the timeline for this?  Is Dec 31, 2006 too soon?
(or not soon enough!?).

-Tony

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Re: [5/5] move_pages: 32bit support (i386,x86_64 and ia64)

[Andrew Morton]

"Luck, Tony" <tony.luck@intel.com> wrote:
>
> > 2. There is a whole range of syscalls missing for ia64 that I basically
> >   interpolated from elsewhere.
> 
> I've been thinking of dropping CONFIG_IA32_SUPPORT completely from ia64.
> I've heard no complaints that new syscalls are not being added to the
> ia32 compat side ... which is an indication that people are not
> actively using this.  Some OSDs have been building with this
> turned off for a while now (perhaps in preparation for "Montecito"
> which no longer has h/w support for the x86 instruction set, or
> perhaps because it represnts a huge block of lightly/barely tested
> code that will have its share of support issues).
> 
> I suppose I should do this by adding an entry to
>  Documentation/feature-removal-schedule.txt

I don't think people actively look in there.  You'd also need to do
something like mark it CONFIG_BROKEN, which will wake people up and might
make them go look to see what happened.  Updating the now-BROKEN help text
would make that nice and easy for them.

> Any thoughts on the timeline for this?  Is Dec 31, 2006 too soon?
> (or not soon enough!?).

You'd know better than we..

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RE: [5/5] move_pages: 32bit support (i386,x86_64 and ia64)

[Christoph Lameter]

On Wed, 24 May 2006, Luck, Tony wrote:

> Any thoughts on the timeline for this?  Is Dec 31, 2006 too soon?
> (or not soon enough!?).

If it does not work then remove it now. Are there any users left?

I vaguely remember some BIOS code having to be executed in ia32 mode in 
order to make some device drives work?

If that is the case then we cannot drop ia32 support at all.

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Re: dropping CONFIG_IA32_SUPPORT from ia64

[Bjorn Helgaas]

On Wednesday 24 May 2006 12:45, Luck, Tony wrote:
> I've been thinking of dropping CONFIG_IA32_SUPPORT completely from ia64.
> I've heard no complaints that new syscalls are not being added to the
> ia32 compat side ... which is an indication that people are not
> actively using this.

Or maybe the people using ia32 compatibility are just running big
apps like Firefox or Open Office that are non-trivial to build for
ia64, but may not care as much about shiny new syscalls.

Later, Tony wrote:
> > Are there any users left?
> I've no idea.  Two OSDs have been shipping the Intel s/w emulator for
> a while now, one installs it by default.  So the number of users is
> probably diminishing.  When people upgrade to Montecito, s/w emulation
> is the only option, which will further reduce the user population.

I'm a bit worried about this.  As I understand it, the Intel
software emulator is not open-source.  There may be distros
like Debian and customer environments where that's not a viable
alternative.

If we remove CONFIG_IA32_SUPPORT, every ia64 box will require
the Intel emulator (or QEMU or some other ill-defined solution)
in order to run ia32 code, even though every processor in the
field today supports ia32 in hardware.

It doesn't feel right to me to remove functionality from machines
in the field and offer only a proprietary alternative.

Bjorn

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Re: dropping CONFIG_IA32_SUPPORT from ia64

[Matt Taggart]

Bjorn Helgaas writes...

> If we remove CONFIG_IA32_SUPPORT, every ia64 box will require
> the Intel emulator (or QEMU or some other ill-defined solution)
> in order to run ia32 code, even though every processor in the
> field today supports ia32 in hardware.
> 
> It doesn't feel right to me to remove functionality from machines
> in the field and offer only a proprietary alternative.

Debian is looking at implementing "multiarch", a way to have libraries
for multiple binary targets install in the same system root.

  http://wiki.debian.org/multiarch

After amd64 systems, ia64 can benefit the most from multiarch. It would
be a shame to see this not happen.

I also agree with Bjorn that the propriatary tool shouldn't be the only
way. To the Intel people on the lists that work on this, what is Intel's
position on open sourcing this technology?

Thanks,

-- 
Matt Taggart
taggart@debian.org

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Re: dropping CONFIG_IA32_SUPPORT from ia64

[Andi Kleen]

> I'm a bit worried about this.  As I understand it, the Intel
> software emulator is not open-source.  There may be distros
> like Debian and customer environments where that's not a viable
> alternative.
> 
> If we remove CONFIG_IA32_SUPPORT, every ia64 box will require
> the Intel emulator (or QEMU or some other ill-defined solution)
> in order to run ia32 code, even though every processor in the
> field today supports ia32 in hardware.
> 
> It doesn't feel right to me to remove functionality from machines
> in the field and offer only a proprietary alternative.

You could just freeze the code down to "security fixes only". 
This means new system calls wouldn't need to be added and most programs
fallback if they don't see the latest and great syscalls anyways.
On the other hand it is usually not very hard to add new syscalls
and most of the other code is shared now anyways.

-Andi

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