As we have learned, the kernel segment consists of various regions. Some are common to all architectures (arch-independent): they include the lowmem region (which contains, among other things, the uncompressed kernel image – its code, data, BSS), the kernel modules region, vmalloc/ioremap regions, and so on.
The precise location within the kernel segment where these regions lie, and indeed which regions may be present, is very arch (CPU)-dependent. To help understand and pin it down for any given system, let's develop a kernel module that queries and prints various details regarding the kernel segment (in fact, if asked to, it also prints some useful user space memory details).
