From: Philippe Gerum <rpm@xenomai.org>
To: Benjamin ZORES <benjamin.zores@domain.hid>
Cc: xenomai-core <xenomai@xenomai.org>
Subject: Re: [Xenomai-core] [PowerPC] Registers Corruption at Context Switch
Date: Fri, 20 Jun 2008 16:42:00 +0200 [thread overview]
Message-ID: <485BC1B8.8040301@domain.hid> (raw)
In-Reply-To: <48593233.7000102@domain.hid>
Benjamin ZORES wrote:
> Philippe Gerum a écrit :
>> See arch/powerpc/switch_32.S, rthal_switch_threads(), for the part that does the
>> actual stack switching.
>>
>> Note that this code is obfuscated by the fact that we have to handle so-called
>> "hybrid" switching, between Xenomai kernel threads (which do not rely on a
>> task_struct), and Linux tasks (Xenomai userland, Linux kthreads, or regular
>> userland Linux). Fortunately, what is saved on the stack in any case is easy to
>> find out.
>>
> Thx for the info.
> Can you tell me why GPR registers would be saved there and FPU ones in
> another function ?
>
Because FPU management with Xenomai involves additional handling, e.g. FPU state
fixup during primary/secondary mode switch, Linux to Xenomai real-time
transitions. That support has to be provided independently from the pure task
switching code.
--
Philippe.
next prev parent reply other threads:[~2008-06-20 14:42 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-06-18 15:28 [Xenomai-core] [PowerPC] Registers Corruption at Context Switch Benjamin ZORES
2008-06-18 15:44 ` Philippe Gerum
2008-06-18 16:05 ` Benjamin ZORES
2008-06-20 14:42 ` Philippe Gerum [this message]
2008-06-19 8:46 ` Benjamin ZORES
2008-06-20 14:38 ` Philippe Gerum
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