Well, the organization of memory in the computer is pretty arbitrary. Code section and Data section is just a way to make it more manageable for us humans (and in modern systems, code section and portions of data can be made read-only so that you don't accidentally write to areas where you don't want to write to).
From the processors perspective, it's all memory, and it can all be used as either instructions or data - the code fed to the processor will tell the processor what is what.
Some modern OS's also prevent the processor from executing data sections - but that is just another matter of the system using the memory management system to prevent you (or someone else) from doing things that you probably don't want to do.
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Mats
