[okl4-developer] Direct IPC from OKLinux userland processes to OKL4 services

[Nelson Tam]

Hi Damien,

On 26/02/2008, at 01:27, Damien Schulz wrote:

> is it possible to have IPC directly from OKLinux userland processes  
> - no matter if it is a good idea or not? So far I've written a  
> procfs module that is able to communicate with OKL4, but I'd like to  
> directly use the IDL interface in my user processes.
>
> If I understand it correctly, every linux process is started as an  
> OKL4 process, so it should be possible anyway. Is there a way to  
> simply allow IPC or would that require further changes in the  
> OKLinux fork() implementation?

That's certainly possible.  Every thread in OKLinux is created using  
the eas_create_thread() function in OKL4.  Threads created in this  
manner are allowed to IPC to other OKL4 service threads.  Therefore,  
as long as you know the thread id of the service you want to IPC to,  
OKLinux userland threads are able to utilise OKL4 services.

For a good example of this in action, take a look at linux/ 
kernel-2.6.10-v1/arch/l4/drivers/ig_serial.c.  The OKLinux kernel uses  
the OKL4 virtual serial device as the serial console, and this file  
shows you how this is setup.

Nelson.