How to register a user-space function as an interrupt handler ?

Wolfgang Denk wd at
Thu May 26 22:35:58 EST 2005


in message <D4FDDD1349B5AC46B68FC26AD8AF42D6226B2C at> you wrote:
> Hi everybody, I'm tryin to adapt a vxWorks-designed application to a
> What I would like to do is to make an emulation of both vxWorks routines
> (intConnect() and intEnable()) in the linux world
> cause I'm not allowed to change that code.

This makes no sense. You cannot "port"  such  code  from  VxWorks  to
Linux without making any changes.

As for your question: in Linux interrupt hadling  happens  in  kernel
context  only.  You cannot register user space functions as interrupt

> Furthermore, I'm a newbie in linux developpment and if I understand
> well, I need to be in kernel-space to call those routines. 


> But here is my problem: the interrupt handler that we call is part of
> the application and uses a lot of #define,semaphores and other 
> ressources of the user-application. So can I implement a new linux
> system call, that will register our user-space-function (my_handler())

This cannot and should not be done. You will have to go through  your
software   design   and   adapt  it  for  the  new  operating  system
environment. Unix has somewhat different concepts how some things get
done, and instead of fighting with this envrionment you should  adapt
to it.

> Don't forget that I have to respect two conditions: my application must
> be run from user-space and I cannot modify the 
> code (my team does not want to support versions).

Simple answer: The job cannot be done under such constraints.

Best regards,

Wolfgang Denk

Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at
"It is better to have tried and failed than to have  failed  to  try,
but the result's the same."                           - Mike Dennison

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