Maple PPC970 kexec crash-dump problems

[Benjamin Walsh <walsh.benj@gmail.com>]

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Hi all,

I am trying to use kexec with a crash dump kernel on a Maple board (Motorola
ATCA6101 to be precise). This board is running a two-CPU PPC970FX. I am
running a 2.6.27-10 kernel and have tried both older kexec-tools and the
newest ones. I have tried SMP and non-SMP kernels.

Using kexec -l to fast boot works correctly. However, loading a crash dump
kernel and triggering a crash via echo c > /proc/sysrq-trigger simply hangs
the board. I have traced the sequence down to after the call to
kexec_copy_flush(), when the CPU returns to real-address mode (bl
real_mode). At this point I have no further debugging information.

Two things could help me:

- Getting the fix if this is a known issue and a fix exists. I have looked
at recent patches and nothing lept to mind, mostly relocatable kernel
support.
- Obtaining the address of the serial port @3f8 in real mode. The init
sequence with udbg ON says that the physical address of the port is
0xf40003f8; however, setting it up in poll mode and trying to stuff
characters in the tx buffer doesn't produce anything.

Has anyone recently tried to use the serial port in real mode ?

Thanks for any help.

Ben

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