On Tue, 2004-08-03 at 18:56, Marc Kleine-Budde wrote:
> On Tue, Aug 03, 2004 at 06:03:53PM +0200, Philippe Gerum wrote:
> > > .shutdown = not really used atm?
>
> > Can be used by skins to intercept any shutdown request kicked by the
> > nucleus itself or some other skin, and perform some housekeeping chores
> > before linking to xnpod_shutdown() themselves (provides for a simple
> > daisy chain mechanism).
>
> I understand the concept of daisy chaining the shutdown (it's documented
> :), but I can find no call of nkpod->svctable.shutdown in the nucleus.
> (I've made a fulltest search of 'shutdown' over fusion, but found only
> things like 'pod.svctable.shutdown = &pse51_shutdown;')
>
It was used when xnpod_fatal() attempted a shutdown as part of its
epilogue. The problem was that calling the shutdown code in such context
was rather unsafe (hey, after all, we are panicking here...), so it does
not anymore. I will reactivate this hook later though, because it's
useful.
> > > .settime = not really used atm?
>
>
> > Same as above for changing the nucleus's idea of time. e.g. your skin
> > might be interested in knowing of internal calls changing the current
> > time using the nucleus API, and not the skin one.
>
> Same as above, I've found no call of svctable.sttime in the nucleus :)
>
Same as above. Code has evolved leaving this hook temporarily unused.
>
> > > .faulthandler = if a trap is rised by the cpu, and a xnthread is active
> > Yes, but a thread is not necessarily active at that moment. The handler
> > should take care of identifying the faulting context.
>
> Hmm - After winding though about 4-5 layers[1]....this function calls
> the svctable.faulthandler, only if a xnthread is active.
>
> int xnpod_trap_fault (void *fltinfo)
>
> {
> if (nkpod == NULL || xnpod_idle_p())
> return 0;
>
> return nkpod->svctable.faulthandler(fltinfo);
> }
>
>
> > > .unload = if another pod should be loaded, the current is ased to
> > > shutdown (used by fusion)
> > Yes. This one has been designed to allow skins to pop out the fusion
> > skin since it is loaded by default, before installing themselves. Some
> > may simply recycle it and install over it, like the new native API does.
>
> this is a nice feature :)
>
>
> > > What about the .shutdown and .settime handlers, are they
> > > going to be used in the future, or even deleted?
> > Nope. Look at the pSOS skin for instance.
>
> okay they are used, but they have no effect, cause ne nucleus never
> calls them. My new question is: Will the nucleus call in the future the
> svctable.settime .shutdown handlers?
>
Yes.
>
> regards - Marc
>
>
> [1] From there fault to the handling.....
>
> 1)
> rthal catches all HW faults from adeos:
> adeos_catch_event(trapnr,&rthal_trap_fault);
>
> 2)
> rthal_trap_fault calls rthal_trap_handler if in RT-mode
> note: rthal_trap_handler is a functionpointer
>
> 3)
> rthal_trap_handler is set by rthal_set_trap_handler
>
> 4)
> during xnarch_init():
> rthal_set_trap_handler(&xnarch_trap_fault);
>
> 5)
> in xnarch_trap_fault():
> xnpod_trap_fault() is called
>
> 6)
> xnpod_trap_fault() finally calls the faulthandler defined in the
> svctable
>
> note: steps 1, 3, 4 are done during system-setup, not runtime
>
> during faul-runtime its:
> adeos -> rthal_trap_fault -> xnarch_trap_fault -> xnpod_trap_fault ->
> svctable.faulthandler
--
Philippe.
