[uClinux-dev] associating an external interrupt with a userland process

John Williams jwilliams at itee.uq.edu.au
Thu Mar 27 22:15:36 EST 2003


Thomas Chen wrote:
> i am thinking about using an external interrupt to "launch" a
> userland process...  ie... when the interrupt occur, the userland
> task (predefined" will be started...
> 
> is this possible under uclinux? can anyone suggest something like
> this

Hmm, maybe a loadable kernel module that registers an interrupt handler, 
which does an exec() to spawn the user process??

Oh no hang on, interrupt handlers are not supposed make system calls.

Maybe you could do it in a bottom half handler.

Or perhaps the interrupt handler could set a flag somewhere in shared 
memory, with a userland process polling that flag?  It would depend on 
what sort of interrupt frequency you were expecting, and the "cost" 
associated with missing one etc.

All just random thoughts, no idea if they would actually work.

John






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