vmlinux MD5 sum

Hi all,

I have a requirement to meet certain software certification specifications that require me to be able to verify that a build of the same source tree can be reproduced exactly with identical binaries. This means that if I compile my source code and calculate a MD5 sum of the ouput binary, then recompile again and recalculate the MD5 on the new binary, the two should match. This does not occur with the vmlinux file. If I compile the uClinux tree, take a md5 of the vmlinux file, then recompile again the MD5 sum of the new vmlinux file does not match the previous one. I did not change any code. just simply remake.

One thing I do know is that the linux kernel contains a timestamp string indicating when the last compile was done. This would be the source of one difference. However, when doing a binary compare of the two files, I find that there are allot of differences, more than just these timestamp strings. Some differences show up in the ELF header section.

Does anyone know how I can identifiy that the two binaries are in fact the same? Does anyone know how I can build the kernel and get the same binary twice?

Thanks in advanced,

Tony