Linux设备驱动remap_pfn_range() 和remap_page_range()

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LDD3的开发环境推荐的是2.6.10，安装了RHEL4-update4，其内核版本为2.6.9.42，编译mmap的程序时报错：Unknown symbol remap_pfn_range

在网上查了下，应将上述报错的函数改为remap_page_range，并且remap_page_range不再推荐使用了，两个内核函数第二个参数定义不相同：

int remap_page_range(struct vm_area_struct *vma,            unsigned long from,             unsigned long phys_addr, //            unsigned long size,             pgprot_t prot)int remap_pfn_range(struct vm_area_struct *vma,            unsigned long addr,            unsigned long pfn,//注意和上述的不同            unsigned long size,            pgprot_t prot)

直接看下面的一段程序，在注释中已经将两个函数的使用区分出来了。使用前，先mknod /dev/mymap c 60 0

#include <linux/delay.h>#include <linux/kernel.h>#include <linux/module.h>#include <linux/init.h>#include <linux/mm.h>#include <linux/fs.h>#include <linux/types.h>#include <linux/delay.h>#include <linux/moduleparam.h>#include <linux/slab.h>#include <linux/errno.h>#include <linux/ioctl.h>#include <linux/cdev.h>#include <linux/string.h>#include <linux/list.h>#include <linux/pci.h>//#include <linux/gpio.h>#define DEVICE_NAME "mymap"static unsigned char array[10]={0,1,2,3,4,5,6,7,8,9};static unsigned char *buffer;static int my_open(struct inode *inode, struct file *file){    return 0;}static int my_map(struct file *filp, struct vm_area_struct *vma){        unsigned long page;    unsigned char i;    unsigned long start = (unsigned long)vma->vm_start;    //unsigned long end =  (unsigned long)vma->vm_end;    unsigned long size = (unsigned long)(vma->vm_end - vma->vm_start);    //得到物理地址    page = virt_to_phys(buffer);        //将用户空间的一个vma虚拟内存区映射到以page开始的一段连续物理页面上    //if(remap_pfn_range(vma,start,page>>PAGE_SHIFT,size,PAGE_SHARED))//第三个参数是页帧号，由物理地址右移PAGE_SHIFT得到if(remap_page_range(vma,start,page,size,PAGE_SHARED))//第三个参数是页帧号，由物理地址右移PAGE_SHIFT得到        return -1;    //往该内存写10字节数据    for(i=0;i<10;i++)        buffer[i] = array[i];        return 0;}static struct file_operations dev_fops = {    .owner    = THIS_MODULE,    .open    = my_open,    .mmap   = my_map,};/*static struct miscdevice misc = {    .minor = MISC_DYNAMIC_MINOR,    .name = DEVICE_NAME,    .fops = &dev_fops,};*/static int __init dev_init(void){    int ret;        //注册混杂设备    //ret = misc_register(&misc);ret = register_chrdev(60, DEVICE_NAME, &dev_fops);    if (ret < 0) {            printk("<1> memory: can't obtain major number %d\n", 60);            return ret;    }    //内存分配    buffer = (unsigned char *)kmalloc(PAGE_SIZE,GFP_KERNEL);    //将该段内存设置为保留    SetPageReserved(virt_to_page(buffer));    return ret;}static void __exit dev_exit(void){    //注销设备    //misc_deregister(&misc); unregister_chrdev(60, DEVICE_NAME);      //清除保留    ClearPageReserved(virt_to_page(buffer));    //释放内存    kfree(buffer);}module_init(dev_init);module_exit(dev_exit);MODULE_LICENSE("Dual BSD/GPL");

应用程序：

#include <unistd.h>#include <stdio.h>#include <stdlib.h>#include <string.h>#include <fcntl.h>#include <linux/fb.h>#include <sys/mman.h>#include <sys/ioctl.h> #define PAGE_SIZE 4096int main(int argc , char *argv[]){    int fd;    int i;    unsigned char *p_map;        //打开设备    fd = open("/dev/mymap",O_RDWR);    if(fd < 0)    {        printf("open fail\n");        exit(1);    }    //内存映射    p_map = (unsigned char *)mmap(0, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED,fd, 0);    if(p_map == MAP_FAILED)    {        printf("mmap fail\n");        goto here;    }    //打印映射后的内存中的前10个字节内容    for(i=0;i<10;i++)        printf("%d\n",p_map[i]);    here:    munmap(p_map, PAGE_SIZE);    return 0;}

makefile文件：

obj-m := testdrv.oPWD       := $(shell pwd)all:make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modulesclean:rm -rf *.o *~ core .*.cmd *.mod.c ./tmp_version

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