problems to boot 2.6.23 kernel on XILINX ppc with 8Mbytes of RAM

Magnus Hjorth mh at
Thu Oct 25 17:00:09 EST 2007

Hello Manu,

Could you try the attached patch to arch/ppc/mm/4xx_mmu.c and see if it 
solves your problem?

Best regards,

manu wrote:
> Hello,
> I work on a custom board based on a virtex 2 pro FPGA and 8Mbytes of SDRAM.
> Untill now I used a 2.4.31 linux ppc kernel with John Williams patches
> and uclinux distribution and everything worked perfectly.
> I've decided to move to the latest 2.6 version from
> ( with an initramfs containing a busybox.
> My complete zImage including the initramfs has a size of 900Kbytes.
> I made some tests with a ML300 board and I managed to get a shell easily.
> When I migrated to the custom board, I had the "Now booting the kernel"
> message and then nothing.
> When I trace the code running on the ppc with the debugger, execution
> seems to be stuck in some early initialization code.
> I managed to reproduce the problem on the ML300 using "mem=8m" parameter
> on the bootline.
> With "mem=16m" the kernel boots correctly.
> I'm really surprised by the amount of RAM required to boot the kernel.
> Is there a way to make it boot with only 8Mbytes of RAM ?
> Thanks for your help.
> Manu
> _______________________________________________
> Linuxppc-embedded mailing list
> Linuxppc-embedded at


Magnus Hjorth, M.Sc.
Omnisys Instruments AB
Gruvgatan 8
SE-421 30  Västra Frölunda, SWEDEN
Phone: +46 31 734 34 09
Fax: +46 31 734 34 29 

-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: 4xx_mmu.patch

More information about the Linuxppc-embedded mailing list