arm: Request to preserve TPIDRURW per thread

arm: Request to preserve TPIDRURW per thread

[André Hentschel]

Hi,
that comes a bit late, but [1] asked for objections.
As you can see in [2] there are more and more applications coming to WinRT, Wine could support them,
but mostly they expect to have the thread environment block (TEB) in TPIDRURW.
This register must be preserved per thread and we have patches for that.

Currently there exist two kernel behaviours:

1. the kernel does not touch TPIDRURW at all ("covert channel")
2. the kernel clears TPIDRURW on thread switch

Attached to [3] you'll find kernel patches you can freely use.
Permission and more info you'll find in [4].
Any hints or suggestions?

[1] http://www.kernelhub.org/?p=2&msg=57979
[2] http://forum.xda-developers.com/showthread.php?t=2092348
[3] http://bugs.winehq.org/show_bug.cgi?id=31322
[4] http://bugs.winehq.org/show_bug.cgi?id=31308
-- 

Best Regards, André Hentschel

Re: arm: Request to preserve TPIDRURW per thread

[Greg KH]

On Tue, Jan 22, 2013 at 01:04:56AM +0100, André Hentschel wrote:
> Hi,
> that comes a bit late, but [1] asked for objections.
> As you can see in [2] there are more and more applications coming to WinRT, Wine could support them,
> but mostly they expect to have the thread environment block (TEB) in TPIDRURW.
> This register must be preserved per thread and we have patches for that.
> 
> Currently there exist two kernel behaviours:
> 
> 1. the kernel does not touch TPIDRURW at all ("covert channel")
> 2. the kernel clears TPIDRURW on thread switch
> 
> Attached to [3] you'll find kernel patches you can freely use.
> Permission and more info you'll find in [4].
> Any hints or suggestions?
> 
> [1] http://www.kernelhub.org/?p=2&msg=57979
> [2] http://forum.xda-developers.com/showthread.php?t=2092348
> [3] http://bugs.winehq.org/show_bug.cgi?id=31322
> [4] http://bugs.winehq.org/show_bug.cgi?id=31308

Please submit the patches to fix this in the way described in
Documentation/SubmittingPatches.  Once they are in Linus's tree, I'll be
glad to take them in the stable tree if they meet the guidelines that
are described in Documentation/stable_kernel_rules.txt.

Does that help?

thanks,

greg k-h

Re: arm: Request to preserve TPIDRURW per thread

[André Hentschel]

Am 22.01.2013 01:11, schrieb Greg KH:
> On Tue, Jan 22, 2013 at 01:04:56AM +0100, André Hentschel wrote:
>> Hi,
>> that comes a bit late, but [1] asked for objections.
>> As you can see in [2] there are more and more applications coming to WinRT, Wine could support them,
>> but mostly they expect to have the thread environment block (TEB) in TPIDRURW.
>> This register must be preserved per thread and we have patches for that.
>>
>> Currently there exist two kernel behaviours:
>>
>> 1. the kernel does not touch TPIDRURW at all ("covert channel")
>> 2. the kernel clears TPIDRURW on thread switch
>>
>> Attached to [3] you'll find kernel patches you can freely use.
>> Permission and more info you'll find in [4].
>> Any hints or suggestions?
>>
>> [1] http://www.kernelhub.org/?p=2&msg=57979
>> [2] http://forum.xda-developers.com/showthread.php?t=2092348
>> [3] http://bugs.winehq.org/show_bug.cgi?id=31322
>> [4] http://bugs.winehq.org/show_bug.cgi?id=31308
> 
> Please submit the patches to fix this in the way described in
> Documentation/SubmittingPatches.  Once they are in Linus's tree, I'll be
> glad to take them in the stable tree if they meet the guidelines that
> are described in Documentation/stable_kernel_rules.txt.
> 
> Does that help?
> 
> thanks,
> 
> greg k-h
> --
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> 

Sure, thx.
It only will take a while, because i'm out for some days. I'll report back.

-- 

Best Regards, André Hentschel

Re: arm: Request to preserve TPIDRURW per thread

[Will Deacon]

On Tue, Jan 22, 2013 at 12:11:43AM +0000, Greg KH wrote:
> On Tue, Jan 22, 2013 at 01:04:56AM +0100, André Hentschel wrote:
> > Hi,
> > that comes a bit late, but [1] asked for objections.
> > As you can see in [2] there are more and more applications coming to WinRT, Wine could support them,
> > but mostly they expect to have the thread environment block (TEB) in TPIDRURW.
> > This register must be preserved per thread and we have patches for that.
> > 
> > Currently there exist two kernel behaviours:
> > 
> > 1. the kernel does not touch TPIDRURW at all ("covert channel")
> > 2. the kernel clears TPIDRURW on thread switch
> > 
> > Attached to [3] you'll find kernel patches you can freely use.
> > Permission and more info you'll find in [4].
> > Any hints or suggestions?
> > 
> > [1] http://www.kernelhub.org/?p=2&msg=57979
> > [2] http://forum.xda-developers.com/showthread.php?t=2092348
> > [3] http://bugs.winehq.org/show_bug.cgi?id=31322
> > [4] http://bugs.winehq.org/show_bug.cgi?id=31308
> 
> Please submit the patches to fix this in the way described in
> Documentation/SubmittingPatches.  Once they are in Linus's tree, I'll be
> glad to take them in the stable tree if they meet the guidelines that
> are described in Documentation/stable_kernel_rules.txt.

Please also send them to linux-arm-kernel@lists.infradead.org, since that's
the happening place for arch/arm/ and they'll likely get reviewed there.

Cheers,

Will