From: Prakash kanthi <pkanthi@yahoo.com>
To: Gary Thomas <gary@chez-thomas.org>
Cc: linuxppc embedded <linuxppc-embedded@lists.linuxppc.org>
Subject: Serious Problem: After Uncompresseing Linux..., what's next
Date: Fri, 20 Dec 2002 13:59:06 -0800 (PST) [thread overview]
Message-ID: <20021220215906.5016.qmail@web41205.mail.yahoo.com> (raw)
In-Reply-To: <20021220170607.22771.qmail@web41207.mail.yahoo.com>
Hi Folks,
I think finally i have idea as to why boot process was
failing. After uncompressing linux image, the code
execution was aborting with an ESR value of
0x08000000, which stands for "ILLEGAL INSTRUCTION".
When i checked the instruction causing this, i figured
that, 'tlbia' (0x00002384) is the culprit. tlbia is a
valid instruction in PPC405 instruction set.
I still don;t understand, how come it is getting
rejected. Am i missing anything? Can anyone please
throw some light on this?
thanks,
Prakash
--- Prakash kanthi <pkanthi@yahoo.com> wrote:
>
> Gary,
>
> I really appreciate your help. Here is what i am
> doing. Sorry it is little long. But was necessasry.
>
> 1. I have a boot loader(xrom.elf) of size around
> 400KB
> which basically have menu driven tests along with an
> option to jump to linux kernel(zImage.initrd.elf).
>
> 2. xrom.elf is compiled to start at 0xfffffffc and
> jump to 0x00000000 to have rest of functionality.
> zImage.initrd.elf is compiled to start at
> 0x00400000.
>
> 3. I load zImage.initrd.elf first and then xrom.elf
> (xilinx tool makes sure that they are loaded to
> corresponding locations based on ELF header).
>
> 4. After loading both, i start running xrom.elf and
> it
> shows up a menu in my UART terminal. I jump to linux
> (0x00400000).
>
> 5. I see that linux is basically reading the board
> info, setting UART, prints some boot messages onto
> it
> and then performs uncompression (gunzip function
> takes
> the rest of linux image and puts the uncompressed
> code
> starting from 0x0).
>
> 6. Up untill, everything is ok. After this, control
> jumps to 0x0 and starts executing.
>
> My problems are,
>
> a. Once the uncompression process is done, i am not
> sure if the image is copied to 0x0 (i do see value
> changes in memory starting from 0x0).
> b. As uncompression process is embedded into
> zImage.initrd.elf, i do not objdump does not tell me
> which function it is going to execute after
> uncompression.
>
> Please suggest.
>
> Thanks,
> Prakash
>
>
>
>
>
> --- Gary Thomas <gary@chez-thomas.org> wrote:
> > On Fri, 2002-12-20 at 09:48, Prakash kanthi wrote:
> > > I do have xilinx tools and i am working with
> their
> > V2P
> > > product. I completely understands what you are
> > said.
> > > But the problem is, right after the
> uncompression
> > and
> > > cpy to 0x00000000, i loose total control because
> i
> > > don't have any clue what is getting executed.
> > >
> >
> > What sort of things can you do with the Xilinx
> > tools? Is
> > there any way to set [hardware] breakpoints or
> > single step?
> >
> > > And also, i have my boot monitor code at
> > 0x00000000,
> > > before uncompress process overwrites it. I see
> > that
> > > some of that code is getting executed after jump
> > to
> > > 0x0. I reason i am overwriting 0x0 is because, i
> > only
> > > have 8MB RAM.
> > >
> >
> > 8M should be plenty of RAM.
> >
> >
>
>
>
** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
next prev parent reply other threads:[~2002-12-20 21:59 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-12-19 16:10 After Uncompresseing Linux..., what's next James Don
2002-12-19 16:39 ` Tom Rini
2002-12-20 16:14 ` Prakash kanthi
2002-12-20 16:32 ` Prakash kanthi
2002-12-20 16:49 ` Jim Potter
2002-12-20 17:02 ` Jim Potter
2002-12-20 16:38 ` Gary Thomas
2002-12-20 16:48 ` Prakash kanthi
2002-12-20 16:52 ` Gary Thomas
2002-12-20 17:06 ` Prakash kanthi
2002-12-20 17:22 ` Gary Thomas
2002-12-20 21:59 ` Prakash kanthi [this message]
2002-12-20 16:47 ` Jim Potter
2002-12-26 22:47 ` Smallest Initrd (ram disk) Prakash kanthi
2002-12-26 22:55 ` Jim Potter
2003-01-13 2:15 ` Prakash kanthi
2003-01-13 7:55 ` Wolfgang Denk
2003-01-14 18:42 ` ramdisk mount problem Prakash kanthi
2003-01-14 18:57 ` Wolfgang Denk
2003-01-15 8:33 ` Frederic Soulier
2003-01-16 4:49 ` Ramdisk details; execve("/bin/sh") output Prakash kanthi
2003-01-16 5:57 ` Hi Anish
2003-01-16 8:00 ` Hi Wolfgang Denk
2003-01-16 8:06 ` Ramdisk details; execve("/bin/sh") output Wolfgang Denk
2002-12-27 0:22 ` Smallest Initrd (ram disk) Wolfgang Denk
-- strict thread matches above, loose matches on Subject: below --
2002-12-23 8:35 Serious Problem: After Uncompresseing Linux..., what's next Jaap-Jan Boor
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