Makefile

# 最后生成的目标，即module_example.ko
obj-m:=module_example.o
CURRENT_PATH := $(shell pwd)
LINUX_KERNEL := $(shell uname -r)
LINUX_KERNEL_PATH := /usr/lib/modules/$(LINUX_KERNEL)/build
all:
	make -C $(LINUX_KERNEL_PATH) M=$(CURRENT_PATH) modules
clean:
	make -C $(LINUX_KERNEL_PATH) M=$(CURRENT_PATH) clean

module_example.c

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>

static int __init lkp_init(void){
    printk("<1>Hello, world! from the kernel space...\n");
    return 0;
}

static void __exit lkp_exit(void){
    printk("<1>Goodbye, world! leaving the kernel space...\n");
}
module_init(lkp_init);
module_exit(lkp_exit);

MODULE_LICENSE("GPL");