"How to change the Magic number"

"How to change the Magic number"

[nreddy]

Hi ALL,

 I have a specific requirement to change the Magic number of the linux
kernel in my embedded system.

 I cound see the Magic number is defined in U-boot files:
 1.include/image.h:#define IH_MAGIC        0x27051956
 2.cpu/ppc4xx/start.S:     .long   0x27051956

  So i can modify in u-boot to make it compatible to my Kernel (i am using
montavista linux version 2.4.20), but i am not able to see this kindof
info anywhere in the kernel source files.
If anyone knows how the linux magic number is generated and what are the
files
 need modifications inorder to change magic number please let me know.


Thnaks in Advance,
Nagi

Re: "How to change the Magic number"

[Wolfgang Denk]

In message <45530.61.95.208.2.1148300461.squirrel@61.95.208.2> you wrote:
> 
>  I have a specific requirement to change the Magic number of the linux
> kernel in my embedded system.

You are off track.

>  I cound see the Magic number is defined in U-boot files:
>  1.include/image.h:#define IH_MAGIC        0x27051956
>  2.cpu/ppc4xx/start.S:     .long   0x27051956

This magic number is only used by U-Boot, and  ther  e  only  in  the
image header. It has no relevance in any way to the LInu xkernel.

>   So i can modify in u-boot to make it compatible to my Kernel (i am using
> montavista linux version 2.4.20), but i am not able to see this kindof
> info anywhere in the kernel source files.

You are looking at the wrong place. This magic number is not used  or
accessed anywhere in the Linu xkernel.

> If anyone knows how the linux magic number is generated and what are the
> files
>  need modifications inorder to change magic number please let me know.

Linux itself has no such magic number. Especially not on PPC.

[But if you find a way to change  that  magic  number,  I  would  not
protest  if  you  added 10 or 20 to the last 4 digits. Just make sure
the change is propagated back to it's origin. :-) ]

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd@denx.de
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