Re: [Xenomai-help] Handling Linux Signals in primary domain context

[Daniele Nicolodi <daniele@domain.hid>]

On 02/06/10 11:15, Philippe Gerum wrote:

> Actually, we could extend this logic and forge a stack frame to return
> to the preempted application code via some userland trampoline code,
> doing the switch:
> 
> [watchdog trigger]
> 	forge_return_frame(on =regs->sp, to =regs->pc);
> 	regs->pc = __oops_I_did_it_again;
> 
> __oops_I_did_it_again:
> 	__xn_migrate(LINUX_DOMAIN);
> 	ret (via forged frame)
> 
> The thing is, that this brings in some arch-dep code to forge a stack
> frame (like the kernel uses for signals), that should rather live in the
> pipeline core.

Am I to naive thinking that this solution would let the user space
choose what to do when the watchdog interrupts the current thread? In
your example, it would be enough to assign to __ops_I_did_it_again a
function pointer to the function that has to be executed.

Probably there will be hard constraint on what this function can do, but
it would be a nice feature for debugging and for solving application
specific issues.

Cheers,
-- 
Daniele