内核模块传参

1.使用module_param()函数传递参数

hello.c

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

MODULE_LICENSE("GPL");

static char *who="world";
static int times=1;    //先声明变量（static型），然后调用module_param 
module_param(times,int,S_IRUGO);
module_param(who,charp,S_IRUGO);
static int hello_init(void)
{
    int i;
    for(i=0;i<times;i++)
    {
        printk(KERN_ALERT "(%d) hello ,%s \r\n",i,who);
    }
    return 0;
}
 static void hello_exit(void)
 {
     printk(KERN_ALERT "Goodbye,%s!\n",who);
 }

 module_init(hello_init);
 module_exit(hello_exit);

makefile

#General Purpose Makefile for cross compile Linux Kernel module
ifneq ($(KERNELRELEASE),)
obj-m := hello.o  #+=是连接字符串
else

ARCH := arm    
CROSS_COMPILE := arm-linux-gnueabihf-
KERN_DIR := /home/zqh/lichee/linux-zero-4.14.y  #选择内核路径
PWD :=$(shell pwd)   #当前路径

all:
        make ARCH=$(ARCH) CROSS_COMPILE=$(CROSS_COMPILE) -C $(KERN_DIR) M=$(PWD) modules    

clean:                                   
        make -C $(KERN_DIR) M=$(shell pwd) modules clean
        rm -rf modules.order
endif
 

2.现象

# insmod hello.ko who="mom" times=5
# dmesg | tail -10
[    6.057104] RTL8723BS: set pairwise key camid:4, addr:e6:02:9b:c8:c8:41, kid:0, type:AES
[    6.068026] RTL8723BS: set group key camid:5, addr:e6:02:9b:c8:c8:41, kid:2, type:AES
[  129.211272] hello: loading out-of-tree module taints kernel.
[  129.217970] (0) hello ,world 
[  151.453028] Goodbye,world!
[  383.426642] (0) hello ,mom 
[  383.429541] (1) hello ,mom 
[  383.432419] (2) hello ,mom 
[  383.435295] (3) hello ,mom 
[  383.438304] (4) hello ,mom