On Mon, Feb 7, 2011 at 7:27 PM, Gilles Chanteperdrix <[email protected]> wrote: > Henri Roosen wrote: >> We are using signal handlers for catching exceptions which our >> application is allowed to make and which we know how to handle. >> >> The current Xenomai implementation is to switch to the secondary >> domain and call the handlers from there. >> Unfortunately this takes too much time for our application and we >> would like to handle the exception without the switch to the secondary >> domain, in primary domain. >> >> Can anyone give some advice how to implement that? >> Will "user-space signals" which was planned for Xenomai 2.6 fulfill this >> need? >> Is there already code available for user-space signals? > > In the 2.5 series, we added some code to support signals. The signals > are multiplexed per-skin in kernel-space, and demultiplexed in > user-space, upon exit of system calls. We implemented a unit test of > this functionality with the "sigtest" skin and user-space test, but they > only work upon return from system calls. > > Then we added support for the "mayday" page, which made us realize, that > maybe implementing signals handling at any time, not only when returning > from system calls, was possible. But then came the realization that in > order to implement that, we would have to fiddle with the FPU, which is > an area where we have a certain tradition for not getting the things > right at the first attempt. So, we kind of stopped here. > > So, if you want some ad-hoc signals upon return from system call, the > task is pretty easy. If you want the full posix signals interface, then > things are going to be a bit harder. > I am afraid it's going to be a bit harder; we would need it when the exception occurs and that is in most cases not at a place in the code where there is a system call :-(.
I was thinking of adding a hook in Xenomai's exception handler before it makes the switch to the secondary domain... but that would of course be a very ugly hack and I don't know if it can be done. Do you have a suggestion? What are the plans with the full posix signals interface? Thanks, > -- > Gilles. > _______________________________________________ Xenomai-help mailing list [email protected] https://mail.gna.org/listinfo/xenomai-help
