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From: Don Burn on 1 Jul 2010 13:31
You cannot get this to work, in fact you are lucky with current in
kernel setup, enough interrupts and DPC stuff can occur to cause you a
problem.

I'd suggest leaving this in the kernel, if you need floating point set
up your own worker thread with floating point. Then use an interlocked
list to insert requests into a queue that the thread processes.


Don Burn (MVP, Windows DKD)
Windows Filesystem and Driver Consulting
Website: http://www.windrvr.com
Blog: http://msmvps.com/blogs/WinDrvr




> -----Original Message-----
> From: Giuseppe [mailto:electrostudio(a)hi-net.it]
> Posted At: Thursday, July 01, 2010 1:09 PM
> Posted To: microsoft.public.win32.programmer.kernel
> Conversation: Execute user code from kernel
> Subject: Re: Execute user code from kernel
>
> I have to acquire an analog signal through A/D converter board, to
perform the
> operations and write the value in the D/A Converter board.
> This should be done approximately every millisecond.
> Currently the function is written in the kernel and works correctly
even if
> windows is loaded to 100%.
>
> To increase flexibility and use floating point operations, I would
transport
> the user-level function.
> I did not want to use real-time operating systems due to their
complexity and
> also can not integrate standard Windows applications.
>
> Thanks.
>
>
>
> "Krzysztof Uchronski" <krzysztof.uchronski(a)biglasagne.com> ha scritto
nel
> messaggio
news:CC91B35C87244FF2BAD1B9EC691E894B(a)NewnhamResearch.local...
> > This is bad idea. By doing that you are not only creating potential
> > security hole (imagine that your UM code you want to run from kernel
> > has been replaced with something else) but also destabilize the
whole
> > system (again your UM code may be trashed and system crash is almost
> > guaranteed). On top of it there is of course a problem of context
> > DpcForIsr is running in (it's arbitrary), basically its code runs in
> > the context of whatever process happened to be an active one (and no
> > you can't switch contexts when you are at DISPATCH_LEVEL) - so you
are
> > usually not in the right UM address space hence you can't safely
> > access your UM code.
> >
> > Anyway, I would suggest to use inverted calls technique (there's
nice
> > article from OSR guys) where one can "notify" UM mode component
(from
> > KM) to do some work.
> >
> > And the major question here is: what are you actually trying to do?
> >
> > Kris
> >
> > -----Original Message-----
> > From: Giuseppe [mailto:electrostudio(a)hi-net.it] Posted At: Thursday,
> > July 01, 2010 10:46 AM Posted To:
> > microsoft.public.win32.programmer.kernel
> > Conversation: Execute user code from kernel
> > Subject: Execute user code from kernel
> >
> > To make more accurate the system should call a function from kernel
-->
> > DpcForIsr (IRQL = DISPATCH_LEVEL) to user-level function.
> >
> > If you can, what limitations are there?
> >
> > Thanks
> >
> >
> >
> >
> > __________ Information from ESET NOD32 Antivirus, version of virus
> > signature database 5242 (20100701) __________
> >
> > The message was checked by ESET NOD32 Antivirus.
> >
> > http://www.eset.com
> >
> >
> >
> >
> > __________ Information from ESET NOD32 Antivirus, version of virus
> > signature database 5243 (20100701) __________
> >
> > The message was checked by ESET NOD32 Antivirus.
> >
> > http://www.eset.com
> >
> >
> >
>
> __________ Information from ESET NOD32 Antivirus, version of virus
signature
> database 5243 (20100701) __________
>
> The message was checked by ESET NOD32 Antivirus.
>
> http://www.eset.com
>
>
>
>
> __________ Information from ESET Smart Security, version of virus
signature
> database 5244 (20100701) __________
>
> The message was checked by ESET Smart Security.
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