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Date: Mon, 09 Mar 2009 18:38:15 +0100
From: Philippe Gerum <rpm@xenomai.org>
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Subject: Re: [Xenomai-core] Watchdog / immediate Linux signal delivery
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To: Jan Kiszka <jan.kiszka@domain.hid>
Cc: xenomai-core <xenomai@xenomai.org>

Jan Kiszka wrote:
> Philippe Gerum wrote:
>> Jan Kiszka wrote:
>>> Meanwhile I played with some light-weight approach to relax a thread
>>> that received a signal (according to do_sigwake_event). Worked, but only
>>> once due to a limitation (if not bug) of I-pipe x86: in __ipipe_run_isr,
>>> it does not handle the case that a non-root handler may alter the
>>> current domain, causing corruptions to the IPIPE_SYNC_FLAG states of the
>>> involved domains.
>> It is not a bug, this is wanted. ISR must neither change the current
>> domain nor migrate CPU; allowing this would open Pandora's box.
> 
> And if there is no way to migrate from within an ISR, we can bury any
> attempt to deliver signals to spinning Xenomai threads - or what other
> context would remain to Xenomai for triggering migration?
>

The two-phase solution I have mentioned would work.

> Jan
> 


-- 
Philippe.