Software Emulation Kernel Panic

Wohlgemuth, Jason jason.wohlgemuth at
Tue Jun 13 05:49:07 EST 2000

Hmmm... Does the kernel completely boot-up?  (As in a shell prompt)  Does
this occur when loading the shell?  What libraries are you using?  Where did
you get those libraries or did you build them yourself?  Or, is this
occurring before the kernel is completely booted?


-----Original Message-----
From: owner-linuxppc-embedded at
[mailto:owner-linuxppc-embedded at]On Behalf Of Lucinda
Sent: Monday, June 12, 2000 2:16 PM
To: linuxppc-embedded at; cort at;
paulus at
Subject: Software Emulation Kernel Panic


On our MPC823-based custom boards, we are experiencing the "Kernel Mode
Software FPU Emulation" panic called from the SoftwareEmulation function in
/linux/arch/ppc/kernel/traps.c in the 2.2.13 kernel. We see this on boot-up
or shortly after.

Could you shed some light on some situations where this may happen? Most
other situations (unimplemented and illegal instructions, floating point,
etc.) would cause the user_mode(regs) call to return a TRUE condition, but
ours apparently returns a FALSE condition, thus the panic. Why does one get
a software emulation exception with the PR bit of the MSR equal to 0?

Any suggestions highly appreciated.

Lucinda Schafer
Staff Software Engineer
Adaptive Micro-Ware, Inc.

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