Hello module explanations

• Headers specific to the Linux kernel: <linux/xxx.h>

• No access to the usual C library, we're doing kernel programming

• An initialization function

• Called when the module is loaded, returns an error code (0 on success, negative value on failure)
• Declared by the module_init() macro: the name of the function doesn't matter, even though modulename_init() is a convention.

• A cleanup function

• Called when the module is unloaded
• Declared by the module_exit() macro.

• Metadata informations declared using MODULE_LICENSE(), MODULE_DESCRIPTION() and MODULE_AUTHOR()