kernel and userland -current as of Jan 20 17:14
kernels compiled with -O2 -msupersparc

Booting a custom UP kernel (TOO) works fine (none of the erros below).
Booting the corresponding MP kernel (TOO.MP) gets lots of core files.

Not sure how useful any of this is... but here's the output...

Resetting ... 

SPARCstation 20 MP (2 X RT625), No Keyboard
ROM Rev. 2.25R hyperSPARC, 160 MB memory installed, Serial #7493664.
Ethernet address 8:0:20:72:58:20, Host ID: 72725820.

Initializing Memory [BREAK]

Type  help  for more information
<#0> ok boot net netbsd.toomp
Boot device: /iommu/sbus/ledma@f,400010/le@f,c00000  File and args: netbsd.toomp
14200 
>> NetBSD/sparc Secondary Boot, Revision 1.13
>> (sjg@void.crufty.net, Sun Jan 19 21:02:39 PST 2003)
Booting netbsd.toomp
net_open: client addr: 192.168.250.2
net_open: subnet mask: 255.255.255.192
net_open: net gateway: 192.168.250.3
net_open: server addr: 192.168.250.10
net_open: server path: /export/diskless/too/root
net_open: file name: /tftpboot/sparc/boot.net
Using BOOTP protocol: ip address: 192.168.250.2, netmask: 255.255.255.192, gateway: 192.168.250.3
root addr=192.168.250.10 path=/export/diskless/too/root
net_open: client addr: 192.168.250.2
net_open: subnet mask: 255.255.255.192
net_open: net gateway: 192.168.250.3
net_open: server addr: 192.168.250.10
net_open: server path: /export/diskless/too/root
net_open: file name: /tftpboot/sparc/boot.net
Using BOOTP protocol: ip address: 192.168.250.2, netmask: 255.255.255.192, gateway: 192.168.250.3
root addr=192.168.250.10 path=/export/diskless/too/root
2704980+97976+314028 [162304+126762]=0x34fad4
OBP version 3, revision 2.25 (plugin rev 2)
[ using 289560 bytes of netbsd ELF symbol table ]
Copyright (c) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003
    The NetBSD Foundation, Inc.  All rights reserved.
Copyright (c) 1982, 1986, 1989, 1991, 1993
    The Regents of the University of California.  All rights reserved.

NetBSD 1.6M (TOO.MP) #0: Tue Jan 21 09:54:49 PST 2003
    sjg@void.crufty.net:/j/obj/NetBSD/current/sparc/obj/g/NetBSD/current/src/sys/arch/sparc/compile/TOO.MP
total memory = 159 MB
avail memory = 143 MB
using 896 buffers containing 8268 KB of memory
bootpath: /iommu@f,e0000000/sbus@f,e0001000/ledma@f,400010/le@f,c00000
mainbus0 (root): SUNW,SPARCstation-20
cpu0 at mainbus0: mid 8: RT620/625 @ 100 MHz, on-chip FPU
cpu0: 256K byte write-back, 64 bytes/line, sw flush: cache enabled
cpu1 at mainbus0: mid 9: RT620/625 @ 100 MHz, on-chip FPU
cpu1: 256K byte write-back, 64 bytes/line, sw flush: cache enabled
obio0 at mainbus0
clock0 at obio0 slot 0 offset 0x200000: mk48t08: hostid 72725820
timer0 at obio0 slot 0 offset 0x300000: delay constant 48
zs0 at obio0 slot 0 offset 0x100000 level 12 softpri 6
zstty0 at zs0 channel 0 (console i/o)
zstty1 at zs0 channel 1
zs1 at obio0 slot 0 offset 0x0 level 12 softpri 6
kbd0 at zs1 channel 0: baud rate 1200
ms0 at zs1 channel 1: baud rate 1200
SUNW,fdtwo at obio0 slot 0 offset 0x700000 level 11 not configured
auxreg0 at obio0 slot 0 offset 0x800000
power0 at obio0 slot 0 offset 0xa01000 level 2
iommu0 at mainbus0 ioaddr 0xe0000000: version 0x3/0x1, page-size 4096, range 64MB
sbus0 at iommu0: clock = 25 MHz
dma0 at sbus0 slot 15 offset 0x400000: dma rev 2
esp0 at dma0 slot 15 offset 0x800000 level 4: ESP200, 40MHz, SCSI ID 7
scsibus0 at esp0: 8 targets, 8 luns per target
ledma0 at sbus0 slot 15 offset 0x400010: dma rev 2
le0 at ledma0 slot 15 offset 0xc00000 level 6: address 08:00:20:72:58:20
le0: 8 receive buffers, 2 transmit buffers
bpp0 at sbus0 slot 15 offset 0x4800000 level 2 (ipl 3): dma rev 2
SUNW,DBRIe at sbus0 slot 14 offset 0x10000 level 9 not configured
qec0 at sbus0 slot 2 offset 0x20000 level 4 (ipl 7): 128K memory
qe0 at qec0 slot 0 offset 0x0 rev 1 address 08:00:20:72:58:20
qe1 at qec0 slot 1 offset 0x0 rev 1 address 08:00:20:72:58:20
qe2 at qec0 slot 2 offset 0x0 rev 1 address 08:00:20:72:58:20
qe3 at qec0 slot 3 offset 0x0 rev 1 address 08:00:20:72:58:20
cgsix0 at sbus0 slot 3 offset 0x0 level 9: SUNW,501-2325, 1152 x 900, rev 11
cgsix0: attached to /dev/fb
eccmemctl0 at mainbus0 ioaddr 0x0: version 0x0/0x2
Kernelized RAIDframe activated
IPsec: Initialized Security Association Processing.
scsibus0: waiting 2 seconds for devices to settle...
sd0 at scsibus0 target 3 lun 0: <SEAGATE, ST34371W SUN4.2G, 7462> disk fixed
sd0: 4094 MB, 3882 cyl, 16 head, 135 sec, 512 bytes/sect x 8385121 sectors
sd0: sync (100.0ns offset 15), 8-bit (10.000MB/s) transfers, tagged queueing
cd0 at scsibus0 target 6 lun 0: <TOSHIBA, XM-4101TASUNSLCD, 1084> cdrom removable
cd0: sync (248.0ns offset 15), 8-bit (4.032MB/s) transfers
root on le0
nfs_boot: trying DHCP/BOOTP
nfs_boot: DHCP next-server: 192.168.250.10
nfs_boot: my_domain=crufty.net
nfs_boot: my_addr=192.168.250.2
nfs_boot: my_mask=255.255.255.192
nfs_boot: gateway=192.168.250.3
root on 192.168.250.10:/export/diskless/too/root
root file system type: nfs
cpu0: booting secondary processors: cpu1
[1]   Segmentation fault (core dumped) date
swapctl: adding /dev/sd0b as swap device at priority 0
Starting file system checks:
/dev/rsd0f: file system is clean; not checking
/dev/rsd0g: file system is clean; not checking
mount: /: Segmentation fault
[1]   Segmentation fault (core dumped) rm -f /fastboot
[1]   Segmentation fault (core dumped) (cd /var/run && ...
Setting tty flags.
Setting sysctl variables:
Starting network.
Hostname: too.crufty.net
NIS domainname: YP.fast
[1]   Segmentation fault (core dumped) route -q add -in...
[1]   Segmentation fault (core dumped) route -q add -in...
[1]   Segmentation fault (core dumped) route -q add -in...
[1]   Segmentation fault (core dumped) route -q add -in...
[1]   Segmentation fault (core dumped) route -q add -in...
[1]   Segmentation fault (core dumped) route -q add -in...
[1]   Segmentation fault (core dumped) route -q add -in...
IPv6 mode: host
Configuring network interfaces:[1]   Bus error (core dumped) ifconfig ${int} ...
 le0bogus interrupt ipl 0x6 pc=0xf0151234 npc=0xf0151238 psr=1e0001c2<S,PS>
xcall(cpu1,0xf0221d38): couldn't ping cpus:
.
[1]   Segmentation fault (core dumped) route add defaul...
Adding interface aliases:
[1]   Segmentation fault (core dumped) sleep ${dadcount}
[1]   Segmentation fault (core dumped) sleep 1
192.168.250.10:/export/diskless/too/root on / type nfs
/dev/sd0f on /var type ffs (local)
Building databases...
kvm_mkdb: not found
install: not found
install: not found
eval: /usr/sbin/wsconscfg: not found
eval: /usr/sbin/wsconscfg: not found
eval: /usr/sbin/wsconscfg: not found
eval: /usr/sbin/wsconscfg: not found
Checking for core dump...
savecore: can't find device 774/12293
Mounting all filesystems...
mount: /: Segmentation fault
mount: /usr: Segmentation fault
mount: /configs: Segmentation fault
mount_nfs: /etc/nsswitch.conf line 12: 'compat' used with other sources
mount: /share: Segmentation fault
mount: /NetBSD: Segmentation fault
Clearing /tmp.
[1]   Segmentation fault (core dumped) rm -rf [a-km-pr-...
[1]   Segmentation fault (core dumped) rm -f ${dmesg_file}
Creating a.out runtime link editor directory cache.
/sbin/ldconfig: 1: Syntax error: "(" unexpected
Checking quotas:eval: /usr/sbin/quotacheck: not found
 done.
eval: /usr/sbin/quotaon: not found
Setting securelevel: kern.securelevel: 0 -> 1
grep: not found
starting local daemons:uname: not found
uname: not found
uname: not found
uname: not found
tr: not found
[1]   Segmentation fault (core dumped) ${DOIT} ${_shell...
.
Updating motd.
sed: not found
cmp: not found
[1]   Segmentation fault (core dumped) Jan 21 18:27:20 init: can't exec getty '/usr/libexec/getty' for port /dev/console: No such file or directory
[BREAK]
Stopped at      cpu_Debugger+0x8:       call            esigcode
db{0}> mach cpu
addr            cpuid   flags   curproc         fpproc
0xf5b82000      0       d000           0x0             0x0
0xf5bc2000      1       f000           0x0             0x0
db{0}> mach cpu 0
using cpu 0
db{0}> t
cpu_Debugger(0x0, 0x30, 0x30, 0xf00, 0x3b4c2, 0xca7d5b00) at zs_abort+0x24
zs_abort(0x0, 0x100, 0xf02c8468, 0xf02709a0, 0x0, 0xfffffffe) at zstty_stint+0x8
8
zstty_stint(0xf0660670, 0x0, 0xf01f8f7c, 0xf02ba940, 0xf0300c00, 0x11f9) at zsc_
intr_hard+0x68
zsc_intr_hard(0x8, 0xf0661ea0, 0xfe000000, 0x809c4000, 0xa00, 0x74) at zshard+0x
40
zshard(0x0, 0xf01f69a8, 0xd00, 0x1e8000e7, 0xf026c400, 0xf01298d8) at sparc_inte
rrupt44c+0x148
sparc_interrupt44c(0x1, 0x1fa0, 0xf5b82000, 0x0, 0x0, 0x1) at idle_enter+0x18
db{0}> mach cpu 1
using cpu 1
db{0}> t         
nmi_soft(0xf5bc6fb0, 0x80000000, 0xe00, 0xf02233cc, 0x1e400fc7, 0x0) at nmi_sun4
m+0x15c
nmi_sun4m(0x1, 0x1fa0, 0xf02794f8, 0x0, 0x0, 0x9) at idle_enter+0x20
db{0}> print $psr
1e400fc5
db{0}> mach prom
Type  'go' to resume
<#0> ok boot net netbsd.too
Resetting ... 

root@too:6# ls -l *.core 
-rw-------  1 root  wheel  208896 Jan 21 18:27 date.core
-rw-------  1 root  wheel  245760 Jan 21 18:27 ifconfig.core
-rw-------  1 root  wheel  258048 Jan 21 18:27 mount_nfs.core
-rw-------  1 root  wheel  196608 Jan 21 18:27 rm.core
-rw-------  1 root  wheel  217088 Jan 21 18:27 route.core
-rw-------  1 root  wheel  258048 Jan 21 18:27 sh.core
-rw-------  1 root  wheel  200704 Jan 21 18:27 sleep.core

The date, sh, rm and sleep cores are all the same:

Core was generated by `sh'.
Program terminated with signal 11, Segmentation fault.

warning: current_sos: Can't read pathname for load map: Input/output error

Reading symbols from /lib/libedit.so.2...(no debugging symbols found)...done.
Loaded symbols for /lib/libedit.so.2
Reading symbols from /lib/libtermcap.so.0...(no debugging symbols found)...
done.
Loaded symbols for /lib/libtermcap.so.0
Reading symbols from /lib/libsparc_v8.so.0...(no debugging symbols found)...
done.
Loaded symbols for /lib/libsparc_v8.so.0
Reading symbols from /lib/libc.so.12...(no debugging symbols found)...done.
Loaded symbols for /lib/libc.so.12
#0  0x101c4ee4 in __setlocale () from /lib/libc.so.12
(gdb) bt
#0  0x101c4ee4 in __setlocale () from /lib/libc.so.12
#1  0x101c49e0 in __setlocale () from /lib/libc.so.12
#2  0x101c48bc in __setlocale_mb_len_max_32 () from /lib/libc.so.12
#3  0x1de50 in main ()
#4  0x11aac in ___start ()

Core was generated by `mount_nfs'.
Program terminated with signal 11, Segmentation fault.

warning: current_sos: Can't read pathname for load map: Input/output error

Reading symbols from /lib/libutil.so.7...(no debugging symbols found)...done.
Loaded symbols for /lib/libutil.so.7
Reading symbols from /lib/libsparc_v8.so.0...(no debugging symbols found)...
done.
Loaded symbols for /lib/libsparc_v8.so.0
Reading symbols from /lib/libc.so.12...(no debugging symbols found)...done.
Loaded symbols for /lib/libc.so.12
#0  0x101825b8 in strcasecmp () from /lib/libc.so.12
(gdb) bt
#0  0x101825b8 in strcasecmp () from /lib/libc.so.12
#1  0x10181e68 in _nscmp () from /lib/libc.so.12
#2  0x1018235c in _nsdbtput () from /lib/libc.so.12
#3  0x10181ab8 in _nsyyparse () from /lib/libc.so.12
#4  0x10182280 in _nsdbtget () from /lib/libc.so.12
#5  0x10182468 in nsdispatch () from /lib/libc.so.12
#6  0x10170324 in getaddrinfo () from /lib/libc.so.12
#7  0x10170210 in getaddrinfo () from /lib/libc.so.12
#8  0x123c0 in getnfsargs ()
#9  0x11e88 in mount_nfs ()
#10 0x116e4 in main ()
#11 0x10f74 in ___start ()
(gdb) 

Core was generated by `route'.
Program terminated with signal 11, Segmentation fault.

warning: current_sos: Can't read pathname for load map: Input/output error

Reading symbols from /lib/libsparc_v8.so.0...(no debugging symbols found)...
done.
Loaded symbols for /lib/libsparc_v8.so.0
Reading symbols from /lib/libc.so.12...(no debugging symbols found)...done.
Loaded symbols for /lib/libc.so.12
#0  0x1013029c in getaddrinfo () from /lib/libc.so.12
(gdb) bt
#0  0x1013029c in getaddrinfo () from /lib/libc.so.12
#1  0x1100c in ___start ()
(gdb)

--sjg