如何编译一个linux下的驱动模块

按照《linux设备驱动开发详解》一书中的步骤实现经典例子"hello，world!"的例子。
具体步骤如下：
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1.源码如下：
/*
* hello.c -- the example of printf "hello world!" in the screen of driver program
*/
#include
#include
MODULE_LICENSE("Dual BSD/GPL");/* declare the license of the module ,it is necessary */
static int hello_init(void)
{
printk(KERN_ALERT "Hello World enter!\n");
return 0;
}
static int hello_exit(void)
{
printk(KERN_ALERT "Hello world exit!\n");
}
module_init(hello_init); /* load the module */
module_exit(hello_exit); /* unload the module */
进入目录：
[root@Alex_linux /]#cd /work/jiakun_test/moduletest
[root@Alex_linux moduletest]# vi hello.c
然后拷入上面书上的源码。
2.编译代码：
1>.首先我在2.4内核的虚拟机上进行编译，编译过程如下：
[root@Alex_linux moduletest]#gcc -D__KERNEL__ -I /usr/src/linux -DMODULE -Wall -O2 -c -o hello.o hello.c
其中-I选项指定内河源码，也就是内核源码树路径。编译结果：
hello.c:1:22: net/sock.h: No such file or directory
hello.c: In function `hello_init':
hello.c:6: warning: implicit declaration of function `printk'
hello.c:6: `KERN_ALERT' undeclared (first use in this function)
hello.c:6: (Each undeclared identifier is reported only once
hello.c:6: for each function it appears in.)
hello.c:6: parse error before string constant
hello.c: In function `hello_exit':
hello.c:11: `KERN_ALERT' undeclared (first use in this function)
hello.c:11: parse error before string constant
hello.c: At top level:
hello.c:13: warning: type defaults to `int' in declaration of `module_init'
hello.c:13: warning: parameter names (without types) in function declaration
hello.c:13: warning: data definition has no type or storage class
hello.c:14: warning: type defaults to `int' in declaration of `module_exit'
hello.c:14: warning: parameter names (without types) in function declaration
hello.c:14: warning: data definition has no type or storage class
在网上查询有网友提示没有引入kernel.h
解决：vi hello.c
在第一行加入：#include
再次编译仍然报KERN_ALERT没有声明
修改编译条件-I，再次编译：
[root@Alex_linux moduletest]#gcc -D__KERNEL__ -I /usr/src/linux -DMODULE -Wall -O2 -c -o hello.o hello.c
[root@Alex_linux moduletest]#ls
hello.c hello.o Makefile
[root@Alex_linux moduletest]#
2>.接着我尝试在2.6内核的虚拟机上进行编译
编译过程如下：
[root@JiaKun moduletest]# ls
hello.c makefile
[root@JiaKun moduletest]# vi hello.c
[root@JiaKun moduletest]# make
make -C /mylinux/kernel/2.4.18-rmk7 M=/home/alex/test/moduletest modules
make: *** /mylinux/kernel/2.4.18-rmk7: No such file or directory. Stop.
make: *** [modules] Error 2
[root@JiaKun moduletest]# vi makefile
[root@JiaKun moduletest]# make
make -C /usr/src/kernels/2.6.18-53.el5-i686 M=/home/alex/test/moduletest modules
make[1]: Entering directory `/usr/src/kernels/2.6.18-53.el5-i686'
scripts/Makefile.build:17: /home/alex/test/moduletest/Makefile: No such file or directory
make[2]: *** No rule to make target `/home/alex/test/moduletest/Makefile'. Stop.
make[1]: *** [_module_/home/alex/test/moduletest] Error 2
make[1]: Leaving directory `/usr/src/kernels/2.6.18-53.el5-i686'
make: *** [modules] Error 2
[root@JiaKun moduletest]# mv makefile Makefile
[root@JiaKun moduletest]# make
make -C /usr/src/kernels/2.6.18-53.el5-i686 M=/home/alex/test/moduletest modules
make[1]: Entering directory `/usr/src/kernels/2.6.18-53.el5-i686'
CC [M] /home/alex/test/moduletest/hello.o
Building modules, stage 2.
MODPOST
CC /home/alex/test/moduletest/hello.mod.o
LD [M] /home/alex/test/moduletest/hello.ko
make[1]: Leaving directory `/usr/src/kernels/2.6.18-53.el5-i686'
[root@JiaKun moduletest]# ls
hello.c hello.ko hello.mod.c hello.mod.o hello.o Makefile Module.symvers