It is powerpc e300c3 MPC8308.
You are correct the alignment fix is only on the Linux side, you can find it 
under arch/powerpc/kernel/align.c
The code that fixes the alignment during align exception (600) works most of 
the time, but sometimes during the alignment fix  "Unrecoverable FP Unavailable 
Exception" occurs.
My suspicion is that the xenomai still holds the FPU, but I not familiar enough 
with the xenomi code.

-----Original Message-----
From: Lennart Sorensen [] 
Sent: Wednesday, April 04, 2018 17:46
To: Sagi Maimon <>
Cc: Seeger, Steven D. (GSFC-582.0)[Embedded Flight Systems, Inc] 
Subject: Re: [Xenomai] Unrecoverable FP Unavailable Exception 801

On Wed, Apr 04, 2018 at 12:57:31PM +0000, Sagi Maimon wrote:
> HI,
> I did it only from Linux side.
> I can try doing it from xenomai side too.
> Please explain how would it help to investigate the problem?

As far as I recall the kernel alignment fixup is only allowed from linux mode 
since it uses linux kernel code.  The realtime side as far as I recall can't 
use it.  So if my memory is correct, any code running in the xenomai realtime 
part must do everything right and not trigger those exceptions.

What CPU is this?  What does /proc/cpuinfo say it is?

Len Sorensen

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