More on the EFIKA

[Andrew Turner]

I have got a little further at booting on an EFIKA.

I noticed there are already TLB exception handlers loaded before boot.
Using these I can read and write to an address in virtual memory. On
the second write the kernel will panic with:

panic: mtx_lock() of spin mutex (null)
@ /a/andrew/freebsd/efika/sys/kern/kern_sx.c:172
KDB: enter: panic
[thread pid 0 tid 0 ]
Stopped at      0x29f3dc:       lwz     r11, r1, 0x0
db> bt
Tracing pid 0 tid 0 td 0x4d89d8
0x0048cc00: at panic+0x134
0x0048cca0: at _mtx_lock_flags+0xb4
0x0048ccd0: at _sx_xlock+0x40
0x0048ccf0: at _vm_map_lock_read+0x40
0x0048cd00: at vm_map_lookup+0x90
0x0048cd40: at vm_fault+0xb0
0x0048ce30: at trap_pfault+0x170
0x0048ce60: at trap+0x23c
0x0048cf00: at powerpc_interrupt+0xac
0x0048cf20: kernel DSI write trap @ 0xd0005000 by powerpc_init+0x410:
srr1=0x3032 r1=0x48cfd0 cr=0x20004024 xer=0 ctr=0x101a5f0
dsisr=0x42000000 0x0048cfd0: at powerpc_init+0x404
0x0048d000: at __start+0x90
db> 

Removing the reads/writes I can the kernel up to the call to
vm_mem_init in the system initialization tasks. The panic is identical
to the one above.

Has anyone got any ideas as to where I can look to fix this panic?

Andrew