My First Linux Module

My First Linux Module

Today, I successfully build my first linux hello module.
So, I write this blog to record this process.

  1. First of all add a directory named hello in the kernel/driver, and add a file hello.c, write codes like bellow:
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#include <linux/init.h>
#include <linux/module.h>

static int __init hello_init(void)
{
    printk(KERN_ERR " Hello, world!\n");
    return 0;
}
static void __exit hello_exit(void)
{
    printk(KERN_ERR " Goodbye, world!\n");
}

module_init(hello_init);
module_exit(hello_exit);

MODULE_AUTHOR("Bob, Zhang");
MODULE_LICENSE("Dual BSD/GPL");

MODULE_DESCRIPTION("A simple hello world demo");
MODULE_ALIAS("A simple module");

  1. Then create a Kconfig file:

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    config HELLO
        tristate "HELLO WORLD Driver!"
        default m
        help
            HELLO WORLD

  2. And create a Makefile file:

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    obj-m += hello.o

  3. Next Add the Kconfig and Makefile into the Kconfig file and Makefile file in parent directory.

  4. Finally run the commands bellow:

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    make ARCH=arm CROSS_COMPILE=$tool_prefix my_kernel_defconfig
    make ARCH=arm CROSS_COMPILE=$tool_prefix modules
    mkdir ./moduls_temp
    make ARCH=arm CROSS_COMPILE=$tool_prefix modules_install INSTALL_MOD_PATH=./modules_temp

At last, the demo run like this: