2.4.20 kernel panics on boot w/ AS2100

[Soren Harward <soren@byu.edu>]

I have an Alphaserver 2100 (aka "Sable") revision 4/200.  I installed
Debian 3.0r1 on it a few days ago and updated everything to "testing".
It's a dual-processor machine, so yesterday I built a new 2.4.20 kernel
with SMP turned on.  However, immediately on boot, the kernel panics
with the following (I copied it on paper from the screen -- sorry if I
got something wrong):

Unable to handle paging request at virtual address 0000000000000000
[lots of 64-bit hex dumps]
Trace: fffffc000081001c
Code: b57e0018 20b13ff0 b75e0000 47f0040b b55e0010 209105d0 <a6e20000>
40810404
Kernel panic: Attempted to kill the idle task!

Since it happenned so early in the boot, I thought it might have been a
problem with being compiled for the wrong processor type (I've seen
similar errors trying to boot an i686 kernel on an i586 machine).  So I
went back to the kernel config and made sure that CONFIG_ALPHA_SABLE was
set, but that CONFIG_ALPHA_EV5 was *not* set and that CONFIG_ALPHA_EV4
was.  See, my AS2100 uses the EV4 processor and most AS2100's use the EV5
processor.  So I recompiled, and still got a kernel panic.  But during this
next compile, I noticed that the Makefile was still using the -Wa,-mev6
switch, which passes "-mev6" (optimize for EV6) to the assembler.  So I
commented that out of the Makefile, and re-re-compiled.  Still got a
kernel panic.  I'm in the middle of re-re-re-compiling using
CONFIG_ALPHA_GENERIC; I'll see if that works.

Anyone have any idea what's going on?  Is it indeed that my kernel is
getting compiled for the wrong processor, or am I completely on the
wrong track?  What else should I try?  Different kernel version?
Different compiler?  Different kernel options?

Again, this is kernel 2.4.20, compiling with gcc 2.95.4, running on
Debian 3.0r1/testing.

-- 
Soren Harward
soren@byu.edu