学步园

#include <linux/module.h>
#include <linux/init.h>
#include <linux/version.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <linux/vmalloc.h>
#include <linux/mman.h>
#include <linux/slab.h>

#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
#include <linux/wrapper.h>
#endif

#define SKELETON_MAJOR 240
#define SKELETON_NAME "skeleton"
#define CASE1 1
#define CASE2 2

static unsigned int counter = 0;
static char string [128];
static int data;

//#define USEASCII

#ifdef USEASCII
static char *kmalloc_area = NULL;
static char *kmalloc_ptr = NULL;
#else
static unsigned int *kmalloc_area = NULL;
static unsigned int *kmalloc_ptr = NULL;
#endif

#define LEN (64*1024)
unsigned long virt_addr;

DECLARE_WAIT_QUEUE_HEAD(skeleton_wait);
static int data_not_ready = 0;

// open function - called when the "file" /dev/skeleton is opened in userspace
static int skeleton_open (struct inode *inode, struct file *file) {
 printk("skeleton_openn");
 // we could do some checking on the flags supplied by "open"
 // i.e. O_NONBLOCK
 // -> set some flag to disable interruptible_sleep_on in skeleton_read
 return 0;
}

// close function - called when the "file" /dev/skeleton is closed in userspace 
static int skeleton_release (struct inode *inode, struct file *file) {
 printk("skeleton_releasen");
 return 0;
}

// read function called when from /dev/skeleton is read
static ssize_t skeleton_read (struct file *file, char *buf,
  size_t count, loff_t *ppos) {
 int len, err;
 
 // check if we have data - if not, sleep
 // wake up in interrupt_handler
 while (data_not_ready) {
  interruptible_sleep_on(&skeleton_wait);
 }
 //data_not_ready = 1;
 
 if( counter <= 0 )
  return 0;
 err = copy_to_user(buf,string,counter);
 if (err != 0)
  return -EFAULT;
 len  = counter;
 counter = 0;
 return len;
}

// write function called when to /dev/skeleton is written
static ssize_t skeleton_write (struct file *file, const char *buf,
  size_t count, loff_t *ppos) {
 int err;
 err = copy_from_user(string,buf,count);
 if (err != 0)
  return -EFAULT;
 counter += count;
 return count;
}

// ioctl - I/O control
static int skeleton_ioctl(struct inode *inode, struct file *file,
  unsigned int cmd, unsigned long arg) {
 int retval = 0;
 switch ( cmd ) {
  case CASE1:/* for writing data to arg */
   if (copy_from_user(&data, (int *)arg, sizeof(int)))
   return -EFAULT;
   break;
  case CASE2:/* for reading data from arg */
   if (copy_to_user((int *)arg, &data, sizeof(int)))
   return -EFAULT;
   break;
  default:
   retval = -EINVAL;
 }
 return retval;
}

#ifndef VMALLOC_VMADDR
#define VMALLOC_VMADDR(x) ((unsigned long)(x))
#endif

// From: http://www.scs.ch/~frey/linux/memorymap.html
volatile void *virt_to_kseg(volatile void *address) {
 pgd_t *pgd; pmd_t *pmd; pte_t *ptep, pte;
 unsigned long va, ret = 0UL;
 va=VMALLOC_VMADDR((unsigned long)address);
 /* get the page directory. Use the kernel memory map. */
 pgd = pgd_offset_k(va);
 /* check whether we found an entry */
 if (!pgd_none(*pgd)) {
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
  /* get the page middle directory */
  pmd = pmd_offset(pgd, va);
#else
  // I'm not sure if we need this, or the line for 2.4
  //    above will work reliably too
  // If you know, please email me
  pud_t *pud = pud_offset(pgd, va);  
  pmd = pmd_offset(pud, va);
#endif
  /* check whether we found an entry */
  if (!pmd_none(*pmd)) {
   /* get a pointer to the page table entry */
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
   ptep = pte_offset(pmd, va);
#else
   ptep = pte_offset_map(pmd, va);
#endif
   pte = *ptep;
   /* check for a valid page */
   if (pte_present(pte)) {
    /* get the address the page is refering to */
    ret = (unsigned long)page_address(pte_page(pte));
    /* add the offset within the page to the page address */
    ret |= (va & (PAGE_SIZE -1));
   }
  }
 }
 return((volatile void *)ret);
}

static int skeleton_mmap(struct file * filp, struct vm_area_struct * vma) {
 int ret;
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
 ret = remap_page_range(vma->vm_start,
   virt_to_phys((void*)((unsigned long)kmalloc_area)),
   vma->vm_end-vma->vm_start,
   PAGE_SHARED);
//          vma->vm_page_prot);
#else
        ret = remap_pfn_range(vma,
               vma->vm_start,
               virt_to_phys((void*)((unsigned long)kmalloc_area)) >> PAGE_SHIFT,
               vma->vm_end-vma->vm_start,
               PAGE_SHARED);
//               vma->vm_page_prot);
#endif
 if(ret != 0) {
  return -EAGAIN;
 }
 return 0;
}

// define which file operations are supported
struct file_operations skeleton_fops = {
 .owner = THIS_MODULE,
 .llseek = NULL,
 .read  = skeleton_read,
 .write = skeleton_write,
 .readdir = NULL,
 .poll  = NULL,
 .ioctl = skeleton_ioctl,
 .mmap  = skeleton_mmap,
 .open  = skeleton_open,
 .flush = NULL,
 .release = skeleton_release,
 .fsync = NULL,
 .fasync = NULL,
 .lock  = NULL,
 //.readv = NULL,
 //.writev = NULL,
};

// initialize module
static int __init skeleton_init_module (void) {
 int i;
#ifndef USEASCII
 int tmp, tmp2;
#endif
 printk("initializing modulen/n");
 
 i = register_chrdev (SKELETON_MAJOR, SKELETON_NAME, &skeleton_fops);
 if (i != 0) return - EIO;
 
 // reserve memory with kmalloc - Allocating Memory in the Kernel
 kmalloc_ptr = kmalloc(LEN + 2 * PAGE_SIZE, GFP_KERNEL);
 if (!kmalloc_ptr) {
  printk("kmalloc failedn/n");
  return 0;
 }
#ifdef USEASCII
 kmalloc_area = (char *)(((unsigned long)kmalloc_ptr + PAGE_SIZE -1) & PAGE_MASK);
#else
 kmalloc_area = (unsigned int *)(((unsigned long)kmalloc_ptr + PAGE_SIZE -1) & PAGE_MASK);
#endif
 for (virt_addr=(unsigned long)kmalloc_area; virt_addr < (unsigned long)kmalloc_area + LEN;
  virt_addr+=PAGE_SIZE) {
   // reserve all pages to make them remapable
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
   mem_map_reserve(virt_to_page(virt_addr));
#else
   SetPageReserved(virt_to_page(virt_addr));
#endif
 }
 printk("kmalloc_area at 0x%p (phys 0x%lx)/n", kmalloc_area,
  virt_to_phys((void *)virt_to_kseg(kmalloc_area)));

#ifdef USEASCII
 // fill allocated memory with 0123456789 ascii
 for( i = 48; i < 58; i++) {
  kmalloc_ptr[i-48] = (char)i;
 }
 i = 0;
 kmalloc_ptr[58-48] = (char)i;
#else
 // fill allocated memory with integers
 tmp = sizeof(int);
 for( i = 0; i < (10 * tmp); i = i + tmp) {
  kmalloc_ptr[i] = (unsigned int)i;
     
  tmp2 = (unsigned int)kmalloc_ptr[i];
  printk("kmalloc_ptr[%d]=%d/n", i, tmp2);
 }
#endif

 return 0;
}

// close and cleanup module
static void __exit skeleton_cleanup_module (void) {
 printk("cleaning up modulen");
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
 for (virt_addr=(unsigned long)kmalloc_area; virt_addr < (unsigned long)kmalloc_area + LEN;
  virt_addr+=PAGE_SIZE) {
   // clear all pages
   ClearPageReserved(virt_to_page(virt_addr));
 }
#endif
 kfree(kmalloc_ptr);
 unregister_chrdev (SKELETON_MAJOR, SKELETON_NAME);
}

module_init(skeleton_init_module);
module_exit(skeleton_cleanup_module);
MODULE_AUTHOR("www.captain.at");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Linux Device Driver Template with MMAP");

 

 

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obj-m:=skeleton.o

 

 

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// Linux Device Driver Template/Skeleton with mmap
// Userspace test program

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <stdio.h>
#include <sys/mman.h>

#define CASE1 1
#define CASE2 2
#define BUFSIZE 64*1024
//extern  void hello(void);
extern  global;
//#define USEASCII

main() {
 int i, fd, len, wlen, tmp, tmp2;
 char string[] = "Skeleton Kernel Module Test";
 char receive[128];
 int data, rdata;

 char * mptr;
 size_t size = BUFSIZE;
#ifdef USEASCII 
 printf("USEASCII/n");
 char buffer[BUFSIZE];
#else
 printf("NO  USEASCII/n");
 unsigned int buffer[BUFSIZE];
#endif
 printf("global=%d/n",global);
 hello();
 printf("global=%d/n",global);
 fd = open("/dev/skeleton", O_RDWR | O_SYNC);
 if( fd == -1) {
  printf("open error.../n");
  exit(0);
 }

 // test device write function
 wlen = strlen(string) + 1;
 len = write(fd, string, wlen);
 if( len == -1 ) {
  printf("write error.../n");
  exit(1);
 }
 printf("String '%s' written to /dev/skeleton/n", string);
 
 // test device read function
 len = read(fd, receive, 128);
 if( len == -1 ) {
  printf("read error...n");
  exit(1);
 }
 printf("String '%s' read from /dev/skeleton/n", receive);

 // test mmap
 mptr = mmap(0, size, PROT_READ | PROT_WRITE, MAP_FILE | MAP_SHARED, fd, 0);
 if(mptr == MAP_FAILED) {
  printf("mmap() failed/n");
  exit(1);
 }
 // write something into the kernel device driver memory allocated by kmalloc
// memcpy(mptr, "Hello World!", 13);
 // clear our local buffer
 memset(buffer, 0, size);
 // read from the kmalloc area in kernel space
 memcpy(buffer, mptr, size-1);

#ifdef USEASCII
 printf("mmap: '%s'/n", buffer);
#else
 tmp = sizeof(int);
 for( i = 0; i < (10 * tmp); i = i + tmp) {
  tmp2 = (unsigned int)buffer[i];
  printf("buffer[%d]=%d/n", i, tmp2);
 }
#endif

 // test ioctl
 data = 0x55555555;
 ioctl(fd, CASE1, &data);
 ioctl(fd, CASE2, &rdata);
 printf("IOCTL test: written: '%x' - received: '%x'/n", data, rdata);

 munmap(mptr, size);
 close(fd);
}