I found the correct exception guys. It means
Privileged Instruction Exception.

--- Prakash kanthi <pkanthi@yahoo.com> wrote:

quoted

Folks,

I just wanted to provide more info on my env. I have
PPC405 based board with no network support forcing
me
to use zImage.initrd.elf.

Can you suggest more on my problem described below?
I
saw the memory values at 0x00000000 onwards after
uncompressing linux and they have changed. But when
the control jumps to 0x0, my board hangs. I see that
ESR is showing a value of 0x80000000, meaning either
illegal instruction or Machine Check.

Can you tell what's going on? What happens next
after
uncompressing? I am thinking it executes
start_kernel
function which calls lock_kernel. Let me know if i
am
wrong.

thanks,
Prakash

--- James Don <JDon@spacebridge.com> wrote:

quoted

I just went thru this myself ... ;-)

1.) Get a BDM/JTAG tool look halt the processor
after you see " Now booting
the kernel" and look for valid asm at 0x0 ... make
sure it mathes your
start.s file ...

2.) Veryfy you have your mem map from ppcboot
matching requirements for the
kernel i.e ram (physical=0x0, virtual=0xc0000000)
and immr (phys 0xff000000
virtual 0xff000000) ... I had my immr in ppc boot

at

quoted

0x02200000 this screwed
me for quite a while ... otherwise you have no
printk ... the memory map is
very important not to screw with some things

depend

quoted

on it (unless your
careful) ...

3.) verify you SMC1 (uart) is getting proper
clocking config ... i.e
bus->brg1 and brg1 is 16 times baud rate ...
otherwise you have no printk

4.) and always always keep in mind your RAM refesh
could be wrong ...
everyone will tell you this even when it has

nothing

quoted

to do with your problem
... try not to ignore them if you are still stuck
;-) But verifying step 1
should prove your ok ...

Best of luck,
Jim


-----Original Message-----
From: Prakash kanthi [mailto:pkanthi@yahoo.com]
Sent: Wednesday, December 18, 2002 7:14 PM
To: LinuxPPC
Subject: After Uncompresseing Linux..., what's

next

quoted

Hi there,

I was trying to load linuxppc_2_4_devel onto my
board.
It goes through the board info read, UART init and
Uncompressing the linux kernel. But after that, i

do

quoted

not see any messages and board hangs.

Here is the UART output:
------------------------------------
OS Booting...

loaded at:     00400000 0060D1CC
board data at: 00000030 00000044
relocated to:  00405C24 00405C38
zimage at:     00406290 004A08FF
initrd at:     004A1000 006097CA
avail ram:     0060E000 007F8000

Linux/PPC load: console=ttyS0,9600 console=tty1
ip=on
root=/dev/xsysace/disc0/pa
rt3 rw
Uncompressing Linux...done.
Now booting the kernel
-------------------------------------------

After the last line, it hangs. I get a feeling

that,

quoted

the uncompressing process is not writing in the
memory
starting from 0x00000000 and, after uncompressing,
it
is jumping into 0x00000000 and is not able to find
anything.

My questions are,
1. How can i make sure that, the uncompressing
process
is going to start writing the data from

0x00000000.

quoted

2. How big a space this uncompressing process

needs?

quoted

And also how much overall memory is required for
running linux. I just have 8MB SDRAM.

3. What is the next step in the booting process?
Which
Device (eth, pci, ide, ???) Initialization?

Your help is appreciated.

thanks,
Prakash