导出模块文件export_symb.c
/*======================================================================
    A simple kernel module to introduce export symbol
          
    The initial developer of the original code is Baohua Song
    <author@linuxdriver.cn>. All Rights Reserved.
======================================================================*/
#include <linux/init.h>                                
#include <linux/module.h>                                
MODULE_LICENSE("Dual BSD/GPL");                                
                                
int add_integar(int a,int b)                                
{                               
 printk(KERN_EMERG " a + b\n");  
    return a+b;                             
} 
                               
int sub_integar(int a,int b)                                
{                               
  printk(KERN_EMERG " a - b\n");
    return a-b;                             
}                            
 
EXPORT_SYMBOL(add_integar);
EXPORT_SYMBOL(sub_integar);
它的Makefile如下：
ifneq ($(KERNELRELEASE),)
    obj-m := export_symb.o
else
    KERNELDIR := /home/mxzh/opt2/utuLinuxfor2440V1.5.3/utu-linux_for_s3c2440_V1.5.3
    PWD := $(shell pwd)

default:
    $(MAKE) -C $(KERNELDIR) M=$(PWD) modules

endif
clean:
    rm *.o *.ko

模块参数文件book.c
#include <linux/init.h>                                
#include <linux/module.h>                                
MODULE_LICENSE("Dual BSD/GPL");                                
                                
static char *book_name = "dissecting Linux Device Driver";              
static int num = 4000;                                
                                
static int book_init(void)                                
{                               
 int a = 0;
    //printk(KERN_INFO " book name:%s\n",book_name); 
   printk(KERN_EMERG " book name:%s\n",book_name);                      
    printk(KERN_EMERG " book num:%d\n",num);        
   a = add_integar(10,8);      
   printk(KERN_EMERG "a = %d\n",a);             
    return 0;                                
}                                
static void book_exit(void)                                
{           
     int b= 0;                    
    printk(KERN_EMERG " Book module exit\n "); 
  b =  sub_integar(20,18);       
   printk(KERN_EMERG "b = %d\n",b);                         
}                                
module_init(book_init);                                
module_exit(book_exit);                                
module_param(num, int, S_IRUGO);                                
module_param(book_name, charp, S_IRUGO);
                                
MODULE_AUTHOR("Song Baohua, author@linuxdriver.cn");
MODULE_DESCRIPTION("A simple Module for testing module params");
MODULE_VERSION("V1.0");
它的Makefile文件：
ifneq ($(KERNELRELEASE),)
    obj-m := book.o
else
    KERNELDIR := /home/mxzh/opt2/utuLinuxfor2440V1.5.3/utu-linux_for_s3c2440_V1.5.3
    PWD := $(shell pwd)

default:
    $(MAKE) -C $(KERNELDIR) M=$(PWD) modules

endif
clean:
    rm *.o *.ko

板子上测试：
/ $ insmod export_symb.ko
/ $ insmod book.ko
<0> book name:dissecting Linux Device Driver
 book num:4000
 a + b
a = 18
/ $ rmmod book.ko
 Book module exit
 <0> a - b
b = 2

传入参数给模块的测试
/ $ insmod book.ko  book_name="my book"  num=88
 book name:my book
 book num:88
 a + b
a = 18
/ $ rmmod book.ko
 Book module exit
 <0> a - b
b = 2
这里要注意的是＝后面不能有空格，否则会出错，insmod不进去

上面是导出函数，传入参数给内核模块，下面是传入参数给一个内核模块，同时导出该参数给其他模块用。见如下：
/**********export_symb.c************/
#include <linux/init.h>                                
#include <linux/module.h>                                
MODULE_LICENSE("Dual BSD/GPL");                                
                           
int add_integar(int a,int b)                                
{                        
  
 printk(KERN_EMERG " a + b\n");  
    return a+b;                             
} 
                               
int sub_integar(int a,int b)                                
{                               
  printk(KERN_EMERG " a - b\n");
    return a-b;                             
}                            
 
EXPORT_SYMBOL(add_integar);
EXPORT_SYMBOL(sub_integar);

/*********************book.c**********/
#include <linux/init.h>                                
#include <linux/module.h>                                
MODULE_LICENSE("Dual BSD/GPL");                                
                                
static char *book_name = "dissecting Linux Device Driver";              
static int num = 4000;                                
                                
static int book_init(void)                                
{                               
 int a = 0;
    //printk(KERN_INFO " book name:%s\n",book_name); 
   printk(KERN_EMERG " book name:%s\n",book_name);                      
    printk(KERN_EMERG " book num:%d\n",num);        
   a = add_integar(10,8);      
   printk(KERN_EMERG "a = %d\n",a);             
    return 0;                                
}                                
static void book_exit(void)                                
{           
     int b= 0;                    
    printk(KERN_EMERG " Book module exit\n "); 
  b =  sub_integar(20,18);       
   printk(KERN_EMERG "b = %d\n",b);                         
}                                
module_init(book_init);                                
module_exit(book_exit);                                
module_param(num, int, S_IRUGO);                                
module_param(book_name, charp, S_IRUGO);
                                
MODULE_AUTHOR("Song Baohua, author@linuxdriver.cn");
MODULE_DESCRIPTION("A simple Module for testing module params");
MODULE_VERSION("V1.0");
 EXPORT_SYMBOL(num);
EXPORT_SYMBOL(book_name);

/****************hello.c******************/
#include <linux/init.h>
#include <linux/module.h>
MODULE_LICENSE("Dual BSD/GPL");
static int hello_init(void)
{
   extern int num;
   extern char *book_name;
  printk("hello,num = %d\n",num);
  printk("hello,book_name = %s\n",book_name);
  printk(KERN_INFO " Hello World enter\n");
  printk(KERN_EMERG " ggggggggggg\n");
 
  return 0;
}
 
static void hello_exit(void)
{
  printk(KERN_INFO " Hello World exit....\n ");
  printk(KERN_EMERG " kkkkk....\n ");
}
 
module_init(hello_init);
module_exit(hello_exit);
 
MODULE_AUTHOR("Song Baohua");
MODULE_DESCRIPTION("A simple Hello World Module");
MODULE_ALIAS("a simplest module");
实验如下：
/button $ insmod export_symb.ko
/button $ insmod book.ko book_name="mxzh book" num=88888
 book name:mxzh book
 book num:88888
export ,bbk_a ...
 a + b
a = 18
/button $ insmod hello.ko
hello,num = 88888
hello,book_name = mxzh book
 Hello World enter
 ggggggggggg