Mastering Linux Kernel Development

Binary layout of a LKM

Modules are built using kbuild makefiles; once the build process completes, an ELF binary file with a .ko (kernel object) extension is generated. Module ELF binaries are appropriately tweaked to add new sections, to differentiate them from other ELF binaries, and to store module-related metadata. The following are the sections in a kernel module:

.gnu.linkonce.this_module	Module structure
.modinfo	Information about the module (Licenses and so on)
__versions	Expected versions of symbols that the module depends on during compile time
__ksymtab*	The table of symbols exported by this module
__kcrctab*	The table of versions of symbols exported by this module
.init	Sections used when initializing
.text, .data ...