Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 880 insertions, 0 deletions

diff --git a/drivers/char/mem.c b/drivers/char/mem.c
new file mode 100644
index 000000000000..947cb3cef816
--- /dev/null
+++ b/drivers/char/mem.c
@@ -0,0 +1,880 @@
+/*
+ *  linux/drivers/char/mem.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  Added devfs support. 
+ *    Jan-11-1998, C. Scott Ananian <cananian@alumni.princeton.edu>
+ *  Shared /dev/zero mmaping support, Feb 2000, Kanoj Sarcar <kanoj@sgi.com>
+ */
+
+#include <linux/config.h>
+#include <linux/mm.h>
+#include <linux/miscdevice.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/mman.h>
+#include <linux/random.h>
+#include <linux/init.h>
+#include <linux/raw.h>
+#include <linux/tty.h>
+#include <linux/capability.h>
+#include <linux/smp_lock.h>
+#include <linux/devfs_fs_kernel.h>
+#include <linux/ptrace.h>
+#include <linux/device.h>
+#include <linux/backing-dev.h>
+
+#include <asm/uaccess.h>
+#include <asm/io.h>
+
+#ifdef CONFIG_IA64
+# include <linux/efi.h>
+#endif
+
+#if defined(CONFIG_S390_TAPE) && defined(CONFIG_S390_TAPE_CHAR)
+extern void tapechar_init(void);
+#endif
+
+/*
+ * Architectures vary in how they handle caching for addresses
+ * outside of main memory.
+ *
+ */
+static inline int uncached_access(struct file *file, unsigned long addr)
+{
+#if defined(__i386__)
+	/*
+	 * On the PPro and successors, the MTRRs are used to set
+	 * memory types for physical addresses outside main memory,
+	 * so blindly setting PCD or PWT on those pages is wrong.
+	 * For Pentiums and earlier, the surround logic should disable
+	 * caching for the high addresses through the KEN pin, but
+	 * we maintain the tradition of paranoia in this code.
+	 */
+	if (file->f_flags & O_SYNC)
+		return 1;
+ 	return !( test_bit(X86_FEATURE_MTRR, boot_cpu_data.x86_capability) ||
+		  test_bit(X86_FEATURE_K6_MTRR, boot_cpu_data.x86_capability) ||
+		  test_bit(X86_FEATURE_CYRIX_ARR, boot_cpu_data.x86_capability) ||
+		  test_bit(X86_FEATURE_CENTAUR_MCR, boot_cpu_data.x86_capability) )
+	  && addr >= __pa(high_memory);
+#elif defined(__x86_64__)
+	/* 
+	 * This is broken because it can generate memory type aliases,
+	 * which can cause cache corruptions
+	 * But it is only available for root and we have to be bug-to-bug
+	 * compatible with i386.
+	 */
+	if (file->f_flags & O_SYNC)
+		return 1;
+	/* same behaviour as i386. PAT always set to cached and MTRRs control the
+	   caching behaviour. 
+	   Hopefully a full PAT implementation will fix that soon. */	   
+	return 0;
+#elif defined(CONFIG_IA64)
+	/*
+	 * On ia64, we ignore O_SYNC because we cannot tolerate memory attribute aliases.
+	 */
+	return !(efi_mem_attributes(addr) & EFI_MEMORY_WB);
+#else
+	/*
+	 * Accessing memory above the top the kernel knows about or through a file pointer
+	 * that was marked O_SYNC will be done non-cached.
+	 */
+	if (file->f_flags & O_SYNC)
+		return 1;
+	return addr >= __pa(high_memory);
+#endif
+}
+
+#ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE
+static inline int valid_phys_addr_range(unsigned long addr, size_t *count)
+{
+	unsigned long end_mem;
+
+	end_mem = __pa(high_memory);
+	if (addr >= end_mem)
+		return 0;
+
+	if (*count > end_mem - addr)
+		*count = end_mem - addr;
+
+	return 1;
+}
+#endif
+
+/*
+ * This funcion reads the *physical* memory. The f_pos points directly to the 
+ * memory location. 
+ */
+static ssize_t read_mem(struct file * file, char __user * buf,
+			size_t count, loff_t *ppos)
+{
+	unsigned long p = *ppos;
+	ssize_t read, sz;
+	char *ptr;
+
+	if (!valid_phys_addr_range(p, &count))
+		return -EFAULT;
+	read = 0;
+#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
+	/* we don't have page 0 mapped on sparc and m68k.. */
+	if (p < PAGE_SIZE) {
+		sz = PAGE_SIZE - p;
+		if (sz > count) 
+			sz = count; 
+		if (sz > 0) {
+			if (clear_user(buf, sz))
+				return -EFAULT;
+			buf += sz; 
+			p += sz; 
+			count -= sz; 
+			read += sz; 
+		}
+	}
+#endif
+
+	while (count > 0) {
+		/*
+		 * Handle first page in case it's not aligned
+		 */
+		if (-p & (PAGE_SIZE - 1))
+			sz = -p & (PAGE_SIZE - 1);
+		else
+			sz = PAGE_SIZE;
+
+		sz = min_t(unsigned long, sz, count);
+
+		/*
+		 * On ia64 if a page has been mapped somewhere as
+		 * uncached, then it must also be accessed uncached
+		 * by the kernel or data corruption may occur
+		 */
+		ptr = xlate_dev_mem_ptr(p);
+
+		if (copy_to_user(buf, ptr, sz))
+			return -EFAULT;
+		buf += sz;
+		p += sz;
+		count -= sz;
+		read += sz;
+	}
+
+	*ppos += read;
+	return read;
+}
+
+static ssize_t write_mem(struct file * file, const char __user * buf, 
+			 size_t count, loff_t *ppos)
+{
+	unsigned long p = *ppos;
+	ssize_t written, sz;
+	unsigned long copied;
+	void *ptr;
+
+	if (!valid_phys_addr_range(p, &count))
+		return -EFAULT;
+
+	written = 0;
+
+#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
+	/* we don't have page 0 mapped on sparc and m68k.. */
+	if (p < PAGE_SIZE) {
+		unsigned long sz = PAGE_SIZE - p;
+		if (sz > count)
+			sz = count;
+		/* Hmm. Do something? */
+		buf += sz;
+		p += sz;
+		count -= sz;
+		written += sz;
+	}
+#endif
+
+	while (count > 0) {
+		/*
+		 * Handle first page in case it's not aligned
+		 */
+		if (-p & (PAGE_SIZE - 1))
+			sz = -p & (PAGE_SIZE - 1);
+		else
+			sz = PAGE_SIZE;
+
+		sz = min_t(unsigned long, sz, count);
+
+		/*
+		 * On ia64 if a page has been mapped somewhere as
+		 * uncached, then it must also be accessed uncached
+		 * by the kernel or data corruption may occur
+		 */
+		ptr = xlate_dev_mem_ptr(p);
+
+		copied = copy_from_user(ptr, buf, sz);
+		if (copied) {
+			ssize_t ret;
+
+			ret = written + (sz - copied);
+			if (ret)
+				return ret;
+			return -EFAULT;
+		}
+		buf += sz;
+		p += sz;
+		count -= sz;
+		written += sz;
+	}
+
+	*ppos += written;
+	return written;
+}
+
+static int mmap_mem(struct file * file, struct vm_area_struct * vma)
+{
+#if defined(__HAVE_PHYS_MEM_ACCESS_PROT)
+	unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
+
+	vma->vm_page_prot = phys_mem_access_prot(file, offset,
+						 vma->vm_end - vma->vm_start,
+						 vma->vm_page_prot);
+#elif defined(pgprot_noncached)
+	unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
+	int uncached;
+
+	uncached = uncached_access(file, offset);
+	if (uncached)
+		vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+#endif
+
+	/* Remap-pfn-range will mark the range VM_IO and VM_RESERVED */
+	if (remap_pfn_range(vma,
+			    vma->vm_start,
+			    vma->vm_pgoff,
+			    vma->vm_end-vma->vm_start,
+			    vma->vm_page_prot))
+		return -EAGAIN;
+	return 0;
+}
+
+static int mmap_kmem(struct file * file, struct vm_area_struct * vma)
+{
+        unsigned long long val;
+	/*
+	 * RED-PEN: on some architectures there is more mapped memory
+	 * than available in mem_map which pfn_valid checks
+	 * for. Perhaps should add a new macro here.
+	 *
+	 * RED-PEN: vmalloc is not supported right now.
+	 */
+	if (!pfn_valid(vma->vm_pgoff))
+		return -EIO;
+	val = (u64)vma->vm_pgoff << PAGE_SHIFT;
+	vma->vm_pgoff = __pa(val) >> PAGE_SHIFT;
+	return mmap_mem(file, vma);
+}
+
+extern long vread(char *buf, char *addr, unsigned long count);
+extern long vwrite(char *buf, char *addr, unsigned long count);
+
+/*
+ * This function reads the *virtual* memory as seen by the kernel.
+ */
+static ssize_t read_kmem(struct file *file, char __user *buf, 
+			 size_t count, loff_t *ppos)
+{
+	unsigned long p = *ppos;
+	ssize_t low_count, read, sz;
+	char * kbuf; /* k-addr because vread() takes vmlist_lock rwlock */
+
+	read = 0;
+	if (p < (unsigned long) high_memory) {
+		low_count = count;
+		if (count > (unsigned long) high_memory - p)
+			low_count = (unsigned long) high_memory - p;
+
+#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
+		/* we don't have page 0 mapped on sparc and m68k.. */
+		if (p < PAGE_SIZE && low_count > 0) {
+			size_t tmp = PAGE_SIZE - p;
+			if (tmp > low_count) tmp = low_count;
+			if (clear_user(buf, tmp))
+				return -EFAULT;
+			buf += tmp;
+			p += tmp;
+			read += tmp;
+			low_count -= tmp;
+			count -= tmp;
+		}
+#endif
+		while (low_count > 0) {
+			/*
+			 * Handle first page in case it's not aligned
+			 */
+			if (-p & (PAGE_SIZE - 1))
+				sz = -p & (PAGE_SIZE - 1);
+			else
+				sz = PAGE_SIZE;
+
+			sz = min_t(unsigned long, sz, low_count);
+
+			/*
+			 * On ia64 if a page has been mapped somewhere as
+			 * uncached, then it must also be accessed uncached
+			 * by the kernel or data corruption may occur
+			 */
+			kbuf = xlate_dev_kmem_ptr((char *)p);
+
+			if (copy_to_user(buf, kbuf, sz))
+				return -EFAULT;
+			buf += sz;
+			p += sz;
+			read += sz;
+			low_count -= sz;
+			count -= sz;
+		}
+	}
+
+	if (count > 0) {
+		kbuf = (char *)__get_free_page(GFP_KERNEL);
+		if (!kbuf)
+			return -ENOMEM;
+		while (count > 0) {
+			int len = count;
+
+			if (len > PAGE_SIZE)
+				len = PAGE_SIZE;
+			len = vread(kbuf, (char *)p, len);
+			if (!len)
+				break;
+			if (copy_to_user(buf, kbuf, len)) {
+				free_page((unsigned long)kbuf);
+				return -EFAULT;
+			}
+			count -= len;
+			buf += len;
+			read += len;
+			p += len;
+		}
+		free_page((unsigned long)kbuf);
+	}
+ 	*ppos = p;
+ 	return read;
+}
+
+
+static inline ssize_t
+do_write_kmem(void *p, unsigned long realp, const char __user * buf,
+	      size_t count, loff_t *ppos)
+{
+	ssize_t written, sz;
+	unsigned long copied;
+
+	written = 0;
+#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
+	/* we don't have page 0 mapped on sparc and m68k.. */
+	if (realp < PAGE_SIZE) {
+		unsigned long sz = PAGE_SIZE - realp;
+		if (sz > count)
+			sz = count;
+		/* Hmm. Do something? */
+		buf += sz;
+		p += sz;
+		realp += sz;
+		count -= sz;
+		written += sz;
+	}
+#endif
+
+	while (count > 0) {
+		char *ptr;
+		/*
+		 * Handle first page in case it's not aligned
+		 */
+		if (-realp & (PAGE_SIZE - 1))
+			sz = -realp & (PAGE_SIZE - 1);
+		else
+			sz = PAGE_SIZE;
+
+		sz = min_t(unsigned long, sz, count);
+
+		/*
+		 * On ia64 if a page has been mapped somewhere as
+		 * uncached, then it must also be accessed uncached
+		 * by the kernel or data corruption may occur
+		 */
+		ptr = xlate_dev_kmem_ptr(p);
+
+		copied = copy_from_user(ptr, buf, sz);
+		if (copied) {
+			ssize_t ret;
+
+			ret = written + (sz - copied);
+			if (ret)
+				return ret;
+			return -EFAULT;
+		}
+		buf += sz;
+		p += sz;
+		realp += sz;
+		count -= sz;
+		written += sz;
+	}
+
+	*ppos += written;
+	return written;
+}
+
+
+/*
+ * This function writes to the *virtual* memory as seen by the kernel.
+ */
+static ssize_t write_kmem(struct file * file, const char __user * buf, 
+			  size_t count, loff_t *ppos)
+{
+	unsigned long p = *ppos;
+	ssize_t wrote = 0;
+	ssize_t virtr = 0;
+	ssize_t written;
+	char * kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */
+
+	if (p < (unsigned long) high_memory) {
+
+		wrote = count;
+		if (count > (unsigned long) high_memory - p)
+			wrote = (unsigned long) high_memory - p;
+
+		written = do_write_kmem((void*)p, p, buf, wrote, ppos);
+		if (written != wrote)
+			return written;
+		wrote = written;
+		p += wrote;
+		buf += wrote;
+		count -= wrote;
+	}
+
+	if (count > 0) {
+		kbuf = (char *)__get_free_page(GFP_KERNEL);
+		if (!kbuf)
+			return wrote ? wrote : -ENOMEM;
+		while (count > 0) {
+			int len = count;
+
+			if (len > PAGE_SIZE)
+				len = PAGE_SIZE;
+			if (len) {
+				written = copy_from_user(kbuf, buf, len);
+				if (written) {
+					ssize_t ret;
+
+					free_page((unsigned long)kbuf);
+					ret = wrote + virtr + (len - written);
+					return ret ? ret : -EFAULT;
+				}
+			}
+			len = vwrite(kbuf, (char *)p, len);
+			count -= len;
+			buf += len;
+			virtr += len;
+			p += len;
+		}
+		free_page((unsigned long)kbuf);
+	}
+
+ 	*ppos = p;
+ 	return virtr + wrote;
+}
+
+#if defined(CONFIG_ISA) || !defined(__mc68000__)
+static ssize_t read_port(struct file * file, char __user * buf,
+			 size_t count, loff_t *ppos)
+{
+	unsigned long i = *ppos;
+	char __user *tmp = buf;
+
+	if (!access_ok(VERIFY_WRITE, buf, count))
+		return -EFAULT; 
+	while (count-- > 0 && i < 65536) {
+		if (__put_user(inb(i),tmp) < 0) 
+			return -EFAULT;  
+		i++;
+		tmp++;
+	}
+	*ppos = i;
+	return tmp-buf;
+}
+
+static ssize_t write_port(struct file * file, const char __user * buf,
+			  size_t count, loff_t *ppos)
+{
+	unsigned long i = *ppos;
+	const char __user * tmp = buf;
+
+	if (!access_ok(VERIFY_READ,buf,count))
+		return -EFAULT;
+	while (count-- > 0 && i < 65536) {
+		char c;
+		if (__get_user(c, tmp)) 
+			return -EFAULT; 
+		outb(c,i);
+		i++;
+		tmp++;
+	}
+	*ppos = i;
+	return tmp-buf;
+}
+#endif
+
+static ssize_t read_null(struct file * file, char __user * buf,
+			 size_t count, loff_t *ppos)
+{
+	return 0;
+}
+
+static ssize_t write_null(struct file * file, const char __user * buf,
+			  size_t count, loff_t *ppos)
+{
+	return count;
+}
+
+#ifdef CONFIG_MMU
+/*
+ * For fun, we are using the MMU for this.
+ */
+static inline size_t read_zero_pagealigned(char __user * buf, size_t size)
+{
+	struct mm_struct *mm;
+	struct vm_area_struct * vma;
+	unsigned long addr=(unsigned long)buf;
+
+	mm = current->mm;
+	/* Oops, this was forgotten before. -ben */
+	down_read(&mm->mmap_sem);
+
+	/* For private mappings, just map in zero pages. */
+	for (vma = find_vma(mm, addr); vma; vma = vma->vm_next) {
+		unsigned long count;
+
+		if (vma->vm_start > addr || (vma->vm_flags & VM_WRITE) == 0)
+			goto out_up;
+		if (vma->vm_flags & (VM_SHARED | VM_HUGETLB))
+			break;
+		count = vma->vm_end - addr;
+		if (count > size)
+			count = size;
+
+		zap_page_range(vma, addr, count, NULL);
+        	zeromap_page_range(vma, addr, count, PAGE_COPY);
+
+		size -= count;
+		buf += count;
+		addr += count;
+		if (size == 0)
+			goto out_up;
+	}
+
+	up_read(&mm->mmap_sem);
+	
+	/* The shared case is hard. Let's do the conventional zeroing. */ 
+	do {
+		unsigned long unwritten = clear_user(buf, PAGE_SIZE);
+		if (unwritten)
+			return size + unwritten - PAGE_SIZE;
+		cond_resched();
+		buf += PAGE_SIZE;
+		size -= PAGE_SIZE;
+	} while (size);
+
+	return size;
+out_up:
+	up_read(&mm->mmap_sem);
+	return size;
+}
+
+static ssize_t read_zero(struct file * file, char __user * buf, 
+			 size_t count, loff_t *ppos)
+{
+	unsigned long left, unwritten, written = 0;
+
+	if (!count)
+		return 0;
+
+	if (!access_ok(VERIFY_WRITE, buf, count))
+		return -EFAULT;
+
+	left = count;
+
+	/* do we want to be clever? Arbitrary cut-off */
+	if (count >= PAGE_SIZE*4) {
+		unsigned long partial;
+
+		/* How much left of the page? */
+		partial = (PAGE_SIZE-1) & -(unsigned long) buf;
+		unwritten = clear_user(buf, partial);
+		written = partial - unwritten;
+		if (unwritten)
+			goto out;
+		left -= partial;
+		buf += partial;
+		unwritten = read_zero_pagealigned(buf, left & PAGE_MASK);
+		written += (left & PAGE_MASK) - unwritten;
+		if (unwritten)
+			goto out;
+		buf += left & PAGE_MASK;
+		left &= ~PAGE_MASK;
+	}
+	unwritten = clear_user(buf, left);
+	written += left - unwritten;
+out:
+	return written ? written : -EFAULT;
+}
+
+static int mmap_zero(struct file * file, struct vm_area_struct * vma)
+{
+	if (vma->vm_flags & VM_SHARED)
+		return shmem_zero_setup(vma);
+	if (zeromap_page_range(vma, vma->vm_start, vma->vm_end - vma->vm_start, vma->vm_page_prot))
+		return -EAGAIN;
+	return 0;
+}
+#else /* CONFIG_MMU */
+static ssize_t read_zero(struct file * file, char * buf, 
+			 size_t count, loff_t *ppos)
+{
+	size_t todo = count;
+
+	while (todo) {
+		size_t chunk = todo;
+
+		if (chunk > 4096)
+			chunk = 4096;	/* Just for latency reasons */
+		if (clear_user(buf, chunk))
+			return -EFAULT;
+		buf += chunk;
+		todo -= chunk;
+		cond_resched();
+	}
+	return count;
+}
+
+static int mmap_zero(struct file * file, struct vm_area_struct * vma)
+{
+	return -ENOSYS;
+}
+#endif /* CONFIG_MMU */
+
+static ssize_t write_full(struct file * file, const char __user * buf,
+			  size_t count, loff_t *ppos)
+{
+	return -ENOSPC;
+}
+
+/*
+ * Special lseek() function for /dev/null and /dev/zero.  Most notably, you
+ * can fopen() both devices with "a" now.  This was previously impossible.
+ * -- SRB.
+ */
+
+static loff_t null_lseek(struct file * file, loff_t offset, int orig)
+{
+	return file->f_pos = 0;
+}
+
+/*
+ * The memory devices use the full 32/64 bits of the offset, and so we cannot
+ * check against negative addresses: they are ok. The return value is weird,
+ * though, in that case (0).
+ *
+ * also note that seeking relative to the "end of file" isn't supported:
+ * it has no meaning, so it returns -EINVAL.
+ */
+static loff_t memory_lseek(struct file * file, loff_t offset, int orig)
+{
+	loff_t ret;
+
+	down(&file->f_dentry->d_inode->i_sem);
+	switch (orig) {
+		case 0:
+			file->f_pos = offset;
+			ret = file->f_pos;
+			force_successful_syscall_return();
+			break;
+		case 1:
+			file->f_pos += offset;
+			ret = file->f_pos;
+			force_successful_syscall_return();
+			break;
+		default:
+			ret = -EINVAL;
+	}
+	up(&file->f_dentry->d_inode->i_sem);
+	return ret;
+}
+
+static int open_port(struct inode * inode, struct file * filp)
+{
+	return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
+}
+
+#define zero_lseek	null_lseek
+#define full_lseek      null_lseek
+#define write_zero	write_null
+#define read_full       read_zero
+#define open_mem	open_port
+#define open_kmem	open_mem
+
+static struct file_operations mem_fops = {
+	.llseek		= memory_lseek,
+	.read		= read_mem,
+	.write		= write_mem,
+	.mmap		= mmap_mem,
+	.open		= open_mem,
+};
+
+static struct file_operations kmem_fops = {
+	.llseek		= memory_lseek,
+	.read		= read_kmem,
+	.write		= write_kmem,
+	.mmap		= mmap_kmem,
+	.open		= open_kmem,
+};
+
+static struct file_operations null_fops = {
+	.llseek		= null_lseek,
+	.read		= read_null,
+	.write		= write_null,
+};
+
+#if defined(CONFIG_ISA) || !defined(__mc68000__)
+static struct file_operations port_fops = {
+	.llseek		= memory_lseek,
+	.read		= read_port,
+	.write		= write_port,
+	.open		= open_port,
+};
+#endif
+
+static struct file_operations zero_fops = {
+	.llseek		= zero_lseek,
+	.read		= read_zero,
+	.write		= write_zero,
+	.mmap		= mmap_zero,
+};
+
+static struct backing_dev_info zero_bdi = {
+	.capabilities	= BDI_CAP_MAP_COPY,
+};
+
+static struct file_operations full_fops = {
+	.llseek		= full_lseek,
+	.read		= read_full,
+	.write		= write_full,
+};
+
+static ssize_t kmsg_write(struct file * file, const char __user * buf,
+			  size_t count, loff_t *ppos)
+{
+	char *tmp;
+	int ret;
+
+	tmp = kmalloc(count + 1, GFP_KERNEL);
+	if (tmp == NULL)
+		return -ENOMEM;
+	ret = -EFAULT;
+	if (!copy_from_user(tmp, buf, count)) {
+		tmp[count] = 0;
+		ret = printk("%s", tmp);
+	}
+	kfree(tmp);
+	return ret;
+}
+
+static struct file_operations kmsg_fops = {
+	.write =	kmsg_write,
+};
+
+static int memory_open(struct inode * inode, struct file * filp)
+{
+	switch (iminor(inode)) {
+		case 1:
+			filp->f_op = &mem_fops;
+			break;
+		case 2:
+			filp->f_op = &kmem_fops;
+			break;
+		case 3:
+			filp->f_op = &null_fops;
+			break;
+#if defined(CONFIG_ISA) || !defined(__mc68000__)
+		case 4:
+			filp->f_op = &port_fops;
+			break;
+#endif
+		case 5:
+			filp->f_mapping->backing_dev_info = &zero_bdi;
+			filp->f_op = &zero_fops;
+			break;
+		case 7:
+			filp->f_op = &full_fops;
+			break;
+		case 8:
+			filp->f_op = &random_fops;
+			break;
+		case 9:
+			filp->f_op = &urandom_fops;
+			break;
+		case 11:
+			filp->f_op = &kmsg_fops;
+			break;
+		default:
+			return -ENXIO;
+	}
+	if (filp->f_op && filp->f_op->open)
+		return filp->f_op->open(inode,filp);
+	return 0;
+}
+
+static struct file_operations memory_fops = {
+	.open		= memory_open,	/* just a selector for the real open */
+};
+
+static const struct {
+	unsigned int		minor;
+	char			*name;
+	umode_t			mode;
+	struct file_operations	*fops;
+} devlist[] = { /* list of minor devices */
+	{1, "mem",     S_IRUSR | S_IWUSR | S_IRGRP, &mem_fops},
+	{2, "kmem",    S_IRUSR | S_IWUSR | S_IRGRP, &kmem_fops},
+	{3, "null",    S_IRUGO | S_IWUGO,           &null_fops},
+#if defined(CONFIG_ISA) || !defined(__mc68000__)
+	{4, "port",    S_IRUSR | S_IWUSR | S_IRGRP, &port_fops},
+#endif
+	{5, "zero",    S_IRUGO | S_IWUGO,           &zero_fops},
+	{7, "full",    S_IRUGO | S_IWUGO,           &full_fops},
+	{8, "random",  S_IRUGO | S_IWUSR,           &random_fops},
+	{9, "urandom", S_IRUGO | S_IWUSR,           &urandom_fops},
+	{11,"kmsg",    S_IRUGO | S_IWUSR,           &kmsg_fops},
+};
+
+static struct class_simple *mem_class;
+
+static int __init chr_dev_init(void)
+{
+	int i;
+
+	if (register_chrdev(MEM_MAJOR,"mem",&memory_fops))
+		printk("unable to get major %d for memory devs\n", MEM_MAJOR);
+
+	mem_class = class_simple_create(THIS_MODULE, "mem");
+	for (i = 0; i < ARRAY_SIZE(devlist); i++) {
+		class_simple_device_add(mem_class,
+					MKDEV(MEM_MAJOR, devlist[i].minor),
+					NULL, devlist[i].name);
+		devfs_mk_cdev(MKDEV(MEM_MAJOR, devlist[i].minor),
+				S_IFCHR | devlist[i].mode, devlist[i].name);
+	}
+	
+	return 0;
+}
+
+fs_initcall(chr_dev_init);