[Xenomai-help] Direct access to I/O ports and physical memory from user-space

[Xenomai-help] Direct access to I/O ports and physical memory from user-space

[Tomas Kalibera]

Hello,

is it possible to access I/O port on x86 solely from Xenomai user-space 
primary domain ? I assume that iopl() and then outb(), inb() should 
work. But, how to avoid switches to secondary domain ?

Similarly, for physical memory, there is an example in Xenomai 
distribution that mmaps /dev/mem. Is there a way to avoid switches here ?

Thanks,
Tomas

Re: [Xenomai-help] Direct access to I/O ports and physical memory from user-space

[M. Koehrer]

Hello Tomas,

outb() and inb() are actually realized by the correspondend x86 CPU commands
(Please see the Intel/AMD references for details).
Thus, there is no mode switch as this not a system call.
The same is with memory mapped IO. I use this regularly to access (proprietary) PCI hardware
directly from user space. This works perfectly.

Regards

Mathias
> Hello,
> 
> is it possible to access I/O port on x86 solely from Xenomai user-space 
> primary domain ? I assume that iopl() and then outb(), inb() should 
> work. But, how to avoid switches to secondary domain ?
> 
> Similarly, for physical memory, there is an example in Xenomai 
> distribution that mmaps /dev/mem. Is there a way to avoid switches here ?
> 
> Thanks,
> Tomas
> 
> 
> _______________________________________________
> Xenomai-help mailing list
> Xenomai-help@domain.hid
> https://mail.gna.org/listinfo/xenomai-help
> 

-- 
Mathias Koehrer
mathias_koehrer@domain.hid


Jetzt komfortabel bei Arcor-Digital TV einsteigen: Mehr Happy Ends, mehr Herzschmerz, mehr Fernsehen! Erleben Sie 50 digitale TV Programme und optional 60 Pay TV Sender, einen elektronischen Programmführer mit Movie Star Bewertungen von TV Movie. Außerdem, aktuelle Filmhits und prickelnde Erotik in der Arcor-Videothek. Infos unter www.arcor.de/tv