Software Emulation Kernel Panic

[Lucinda Schafer]

Greetings:

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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