arch/i386/kernel/cpu/mtrr/if.c - maze/linux - Git at Google

 #include <linux/init.h>
 #include <linux/proc_fs.h>
 #include <linux/ctype.h>
 #include <linux/module.h>
 #include <linux/seq_file.h>
 #include <asm/uaccess.h>

 #define LINE_SIZE 80

 #include <asm/mtrr.h>
 #include "mtrr.h"

 /* RED-PEN: this is accessed without any locking */
 extern unsigned int *usage_table;


 #define FILE_FCOUNT(f) (((struct seq_file *)((f)->private_data))->private)

 static char *mtrr_strings[MTRR_NUM_TYPES] =
 {
     "uncachable",               /* 0 */
     "write-combining",          /* 1 */
     "?",                        /* 2 */
     "?",                        /* 3 */
     "write-through",            /* 4 */
     "write-protect",            /* 5 */
     "write-back",               /* 6 */
 };

 char *mtrr_attrib_to_str(int x)
 {
 	return (x <= 6) ? mtrr_strings[x] : "?";
 }

 #ifdef CONFIG_PROC_FS

 static int
 mtrr_file_add(unsigned long base, unsigned long size,
 	      unsigned int type, char increment, struct file *file, int page)
 {
 	int reg, max;
 	unsigned int *fcount = FILE_FCOUNT(file);

 	max = num_var_ranges;
 	if (fcount == NULL) {
 		fcount = kmalloc(max * sizeof *fcount, GFP_KERNEL);
 		if (!fcount)
 			return -ENOMEM;
 		memset(fcount, 0, max * sizeof *fcount);
 		FILE_FCOUNT(file) = fcount;
 	}
 	if (!page) {
 		if ((base & (PAGE_SIZE - 1)) || (size & (PAGE_SIZE - 1)))
 			return -EINVAL;
 		base >>= PAGE_SHIFT;
 		size >>= PAGE_SHIFT;
 	}
 	reg = mtrr_add_page(base, size, type, 1);
 	if (reg >= 0)
 		++fcount[reg];
 	return reg;
 }

 static int
 mtrr_file_del(unsigned long base, unsigned long size,
 	      struct file *file, int page)
 {
 	int reg;
 	unsigned int *fcount = FILE_FCOUNT(file);

 	if (!page) {
 		if ((base & (PAGE_SIZE - 1)) || (size & (PAGE_SIZE - 1)))
 			return -EINVAL;
 		base >>= PAGE_SHIFT;
 		size >>= PAGE_SHIFT;
 	}
 	reg = mtrr_del_page(-1, base, size);
 	if (reg < 0)
 		return reg;
 	if (fcount == NULL)
 		return reg;
 	if (fcount[reg] < 1)
 		return -EINVAL;
 	--fcount[reg];
 	return reg;
 }

 /* RED-PEN: seq_file can seek now. this is ignored. */
 static ssize_t
 mtrr_write(struct file *file, const char __user *buf, size_t len, loff_t * ppos)
 /*  Format of control line:
     "base=%Lx size=%Lx type=%s"     OR:
     "disable=%d"
 */
 {
 	int i, err;
 	unsigned long reg;
 	unsigned long long base, size;
 	char *ptr;
 	char line[LINE_SIZE];
 	size_t linelen;

 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
 	if (!len)
 		return -EINVAL;
 	memset(line, 0, LINE_SIZE);
 	if (len > LINE_SIZE)
 		len = LINE_SIZE;
 	if (copy_from_user(line, buf, len - 1))
 		return -EFAULT;
 	linelen = strlen(line);
 	ptr = line + linelen - 1;
 	if (linelen && *ptr == '\n')
 		*ptr = '\0';
 	if (!strncmp(line, "disable=", 8)) {
 		reg = simple_strtoul(line + 8, &ptr, 0);
 		err = mtrr_del_page(reg, 0, 0);
 		if (err < 0)
 			return err;
 		return len;
 	}
 	if (strncmp(line, "base=", 5))
 		return -EINVAL;
 	base = simple_strtoull(line + 5, &ptr, 0);
 	for (; isspace(*ptr); ++ptr) ;
 	if (strncmp(ptr, "size=", 5))
 		return -EINVAL;
 	size = simple_strtoull(ptr + 5, &ptr, 0);
 	if ((base & 0xfff) || (size & 0xfff))
 		return -EINVAL;
 	for (; isspace(*ptr); ++ptr) ;
 	if (strncmp(ptr, "type=", 5))
 		return -EINVAL;
 	ptr += 5;
 	for (; isspace(*ptr); ++ptr) ;
 	for (i = 0; i < MTRR_NUM_TYPES; ++i) {
 		if (strcmp(ptr, mtrr_strings[i]))
 			continue;
 		base >>= PAGE_SHIFT;
 		size >>= PAGE_SHIFT;
 		err =
 		    mtrr_add_page((unsigned long) base, (unsigned long) size, i,
 				  1);
 		if (err < 0)
 			return err;
 		return len;
 	}
 	return -EINVAL;
 }

 static long
 mtrr_ioctl(struct file *file, unsigned int cmd, unsigned long __arg)
 {
 	int err = 0;
 	mtrr_type type;
 	struct mtrr_sentry sentry;
 	struct mtrr_gentry gentry;
 	void __user *arg = (void __user *) __arg;

 	switch (cmd) {
 	case MTRRIOC_ADD_ENTRY:
 	case MTRRIOC_SET_ENTRY:
 	case MTRRIOC_DEL_ENTRY:
 	case MTRRIOC_KILL_ENTRY:
 	case MTRRIOC_ADD_PAGE_ENTRY:
 	case MTRRIOC_SET_PAGE_ENTRY:
 	case MTRRIOC_DEL_PAGE_ENTRY:
 	case MTRRIOC_KILL_PAGE_ENTRY:
 		if (copy_from_user(&sentry, arg, sizeof sentry))
 			return -EFAULT;
 		break;
 	case MTRRIOC_GET_ENTRY:
 	case MTRRIOC_GET_PAGE_ENTRY:
 		if (copy_from_user(&gentry, arg, sizeof gentry))
 			return -EFAULT;
 		break;
 #ifdef CONFIG_COMPAT
 	case MTRRIOC32_ADD_ENTRY:
 	case MTRRIOC32_SET_ENTRY:
 	case MTRRIOC32_DEL_ENTRY:
 	case MTRRIOC32_KILL_ENTRY:
 	case MTRRIOC32_ADD_PAGE_ENTRY:
 	case MTRRIOC32_SET_PAGE_ENTRY:
 	case MTRRIOC32_DEL_PAGE_ENTRY:
 	case MTRRIOC32_KILL_PAGE_ENTRY: {
 		struct mtrr_sentry32 __user *s32 = (struct mtrr_sentry32 __user *)__arg;
 		err = get_user(sentry.base, &s32->base);
 		err |= get_user(sentry.size, &s32->size);
 		err |= get_user(sentry.type, &s32->type);
 		if (err)
 			return err;
 		break;
 	}
 	case MTRRIOC32_GET_ENTRY:
 	case MTRRIOC32_GET_PAGE_ENTRY: {
 		struct mtrr_gentry32 __user *g32 = (struct mtrr_gentry32 __user *)__arg;
 		err = get_user(gentry.regnum, &g32->regnum);
 		err |= get_user(gentry.base, &g32->base);
 		err |= get_user(gentry.size, &g32->size);
 		err |= get_user(gentry.type, &g32->type);
 		if (err)
 			return err;
 		break;
 	}
 #endif
 	}

 	switch (cmd) {
 	default:
 		return -ENOTTY;
 	case MTRRIOC_ADD_ENTRY:
 		if (!capable(CAP_SYS_ADMIN))
 			return -EPERM;
 		err =
 		    mtrr_file_add(sentry.base, sentry.size, sentry.type, 1,
 				  file, 0);
 		break;
 	case MTRRIOC_SET_ENTRY:
 		if (!capable(CAP_SYS_ADMIN))
 			return -EPERM;
 		err = mtrr_add(sentry.base, sentry.size, sentry.type, 0);
 		break;
 	case MTRRIOC_DEL_ENTRY:
 		if (!capable(CAP_SYS_ADMIN))
 			return -EPERM;
 		err = mtrr_file_del(sentry.base, sentry.size, file, 0);
 		break;
 	case MTRRIOC_KILL_ENTRY:
 		if (!capable(CAP_SYS_ADMIN))
 			return -EPERM;
 		err = mtrr_del(-1, sentry.base, sentry.size);
 		break;
 	case MTRRIOC_GET_ENTRY:
 		if (gentry.regnum >= num_var_ranges)
 			return -EINVAL;
 		mtrr_if->get(gentry.regnum, &gentry.base, &gentry.size, &type);

 		/* Hide entries that go above 4GB */
 		if (gentry.base + gentry.size > 0x100000
 		    || gentry.size == 0x100000)
 			gentry.base = gentry.size = gentry.type = 0;
 		else {
 			gentry.base <<= PAGE_SHIFT;
 			gentry.size <<= PAGE_SHIFT;
 			gentry.type = type;
 		}

 		break;
 	case MTRRIOC_ADD_PAGE_ENTRY:
 		if (!capable(CAP_SYS_ADMIN))
 			return -EPERM;
 		err =
 		    mtrr_file_add(sentry.base, sentry.size, sentry.type, 1,
 				  file, 1);
 		break;
 	case MTRRIOC_SET_PAGE_ENTRY:
 		if (!capable(CAP_SYS_ADMIN))
 			return -EPERM;
 		err = mtrr_add_page(sentry.base, sentry.size, sentry.type, 0);
 		break;
 	case MTRRIOC_DEL_PAGE_ENTRY:
 		if (!capable(CAP_SYS_ADMIN))
 			return -EPERM;
 		err = mtrr_file_del(sentry.base, sentry.size, file, 1);
 		break;
 	case MTRRIOC_KILL_PAGE_ENTRY:
 		if (!capable(CAP_SYS_ADMIN))
 			return -EPERM;
 		err = mtrr_del_page(-1, sentry.base, sentry.size);
 		break;
 	case MTRRIOC_GET_PAGE_ENTRY:
 		if (gentry.regnum >= num_var_ranges)
 			return -EINVAL;
 		mtrr_if->get(gentry.regnum, &gentry.base, &gentry.size, &type);
 		gentry.type = type;
 		break;
 	}

 	if (err)
 		return err;

 	switch(cmd) {
 	case MTRRIOC_GET_ENTRY:
 	case MTRRIOC_GET_PAGE_ENTRY:
 		if (copy_to_user(arg, &gentry, sizeof gentry))
 			err = -EFAULT;
 		break;
 #ifdef CONFIG_COMPAT
 	case MTRRIOC32_GET_ENTRY:
 	case MTRRIOC32_GET_PAGE_ENTRY: {
 		struct mtrr_gentry32 __user *g32 = (struct mtrr_gentry32 __user *)__arg;
 		err = put_user(gentry.base, &g32->base);
 		err |= put_user(gentry.size, &g32->size);
 		err |= put_user(gentry.regnum, &g32->regnum);
 		err |= put_user(gentry.type, &g32->type);
 		break;
 	}
 #endif
 	}
 	return err;
 }

 static int
 mtrr_close(struct inode *ino, struct file *file)
 {
 	int i, max;
 	unsigned int *fcount = FILE_FCOUNT(file);

 	if (fcount != NULL) {
 		max = num_var_ranges;
 		for (i = 0; i < max; ++i) {
 			while (fcount[i] > 0) {
 				mtrr_del(i, 0, 0);
 				--fcount[i];
 			}
 		}
 		kfree(fcount);
 		FILE_FCOUNT(file) = NULL;
 	}
 	return single_release(ino, file);
 }

 static int mtrr_seq_show(struct seq_file *seq, void *offset);

 static int mtrr_open(struct inode *inode, struct file *file)
 {
 	if (!mtrr_if)
 		return -EIO;
 	if (!mtrr_if->get)
 		return -ENXIO;
 	return single_open(file, mtrr_seq_show, NULL);
 }

 static struct file_operations mtrr_fops = {
 	.owner   = THIS_MODULE,
 	.open	 = mtrr_open,
 	.read    = seq_read,
 	.llseek  = seq_lseek,
 	.write   = mtrr_write,
 	.unlocked_ioctl = mtrr_ioctl,
 	.compat_ioctl = mtrr_ioctl,
 	.release = mtrr_close,
 };


 static struct proc_dir_entry *proc_root_mtrr;


 static int mtrr_seq_show(struct seq_file *seq, void *offset)
 {
 	char factor;
 	int i, max, len;
 	mtrr_type type;
 	unsigned long base;
 	unsigned int size;

 	len = 0;
 	max = num_var_ranges;
 	for (i = 0; i < max; i++) {
 		mtrr_if->get(i, &base, &size, &type);
 		if (size == 0)
 			usage_table[i] = 0;
 		else {
 			if (size < (0x100000 >> PAGE_SHIFT)) {
 				/* less than 1MB */
 				factor = 'K';
 				size <<= PAGE_SHIFT - 10;
 			} else {
 				factor = 'M';
 				size >>= 20 - PAGE_SHIFT;
 			}
 			/* RED-PEN: base can be > 32bit */
 			len += seq_printf(seq,
 				   "reg%02i: base=0x%05lx000 (%4liMB), size=%4i%cB: %s, count=%d\n",
 			     i, base, base >> (20 - PAGE_SHIFT), size, factor,
 			     mtrr_attrib_to_str(type), usage_table[i]);
 		}
 	}
 	return 0;
 }

 static int __init mtrr_if_init(void)
 {
 	struct cpuinfo_x86 *c = &boot_cpu_data;

 	if ((!cpu_has(c, X86_FEATURE_MTRR)) &&
 	    (!cpu_has(c, X86_FEATURE_K6_MTRR)) &&
 	    (!cpu_has(c, X86_FEATURE_CYRIX_ARR)) &&
 	    (!cpu_has(c, X86_FEATURE_CENTAUR_MCR)))
 		return -ENODEV;

 	proc_root_mtrr =
 	    create_proc_entry("mtrr", S_IWUSR | S_IRUGO, &proc_root);
 	if (proc_root_mtrr) {
 		proc_root_mtrr->owner = THIS_MODULE;
 		proc_root_mtrr->proc_fops = &mtrr_fops;
 	}
 	return 0;
 }

 arch_initcall(mtrr_if_init);
 #endif			/*  CONFIG_PROC_FS  */
	#include <linux/init.h>
	#include <linux/proc_fs.h>
	#include <linux/ctype.h>
	#include <linux/module.h>
	#include <linux/seq_file.h>
	#include <asm/uaccess.h>

	#define LINE_SIZE 80

	#include <asm/mtrr.h>
	#include "mtrr.h"

	/* RED-PEN: this is accessed without any locking */
	extern unsigned int *usage_table;


	#define FILE_FCOUNT(f) (((struct seq_file *)((f)->private_data))->private)

	static char *mtrr_strings[MTRR_NUM_TYPES] =
	{
	"uncachable", /* 0 */
	"write-combining", /* 1 */
	"?", /* 2 */
	"?", /* 3 */
	"write-through", /* 4 */
	"write-protect", /* 5 */
	"write-back", /* 6 */
	};

	char *mtrr_attrib_to_str(int x)
	{
	return (x <= 6) ? mtrr_strings[x] : "?";
	}

	#ifdef CONFIG_PROC_FS

	static int
	mtrr_file_add(unsigned long base, unsigned long size,
	unsigned int type, char increment, struct file *file, int page)
	{
	int reg, max;
	unsigned int *fcount = FILE_FCOUNT(file);

	max = num_var_ranges;
	if (fcount == NULL) {
	fcount = kmalloc(max * sizeof *fcount, GFP_KERNEL);
	if (!fcount)
	return -ENOMEM;
	memset(fcount, 0, max * sizeof *fcount);
	FILE_FCOUNT(file) = fcount;
	}
	if (!page) {
	if ((base & (PAGE_SIZE - 1)) \|\| (size & (PAGE_SIZE - 1)))
	return -EINVAL;
	base >>= PAGE_SHIFT;
	size >>= PAGE_SHIFT;
	}
	reg = mtrr_add_page(base, size, type, 1);
	if (reg >= 0)
	++fcount[reg];
	return reg;
	}

	static int
	mtrr_file_del(unsigned long base, unsigned long size,
	struct file *file, int page)
	{
	int reg;
	unsigned int *fcount = FILE_FCOUNT(file);

	if (!page) {
	if ((base & (PAGE_SIZE - 1)) \|\| (size & (PAGE_SIZE - 1)))
	return -EINVAL;
	base >>= PAGE_SHIFT;
	size >>= PAGE_SHIFT;
	}
	reg = mtrr_del_page(-1, base, size);
	if (reg < 0)
	return reg;
	if (fcount == NULL)
	return reg;
	if (fcount[reg] < 1)
	return -EINVAL;
	--fcount[reg];
	return reg;
	}

	/* RED-PEN: seq_file can seek now. this is ignored. */
	static ssize_t
	mtrr_write(struct file file, const char __user buf, size_t len, loff_t * ppos)
	/* Format of control line:
	"base=%Lx size=%Lx type=%s" OR:
	"disable=%d"
	*/
	{
	int i, err;
	unsigned long reg;
	unsigned long long base, size;
	char *ptr;
	char line[LINE_SIZE];
	size_t linelen;

	if (!capable(CAP_SYS_ADMIN))
	return -EPERM;
	if (!len)
	return -EINVAL;
	memset(line, 0, LINE_SIZE);
	if (len > LINE_SIZE)
	len = LINE_SIZE;
	if (copy_from_user(line, buf, len - 1))
	return -EFAULT;
	linelen = strlen(line);
	ptr = line + linelen - 1;
	if (linelen && *ptr == '\n')
	*ptr = '\0';
	if (!strncmp(line, "disable=", 8)) {
	reg = simple_strtoul(line + 8, &ptr, 0);
	err = mtrr_del_page(reg, 0, 0);
	if (err < 0)
	return err;
	return len;
	}
	if (strncmp(line, "base=", 5))
	return -EINVAL;
	base = simple_strtoull(line + 5, &ptr, 0);
	for (; isspace(*ptr); ++ptr) ;
	if (strncmp(ptr, "size=", 5))
	return -EINVAL;
	size = simple_strtoull(ptr + 5, &ptr, 0);
	if ((base & 0xfff) \|\| (size & 0xfff))
	return -EINVAL;
	for (; isspace(*ptr); ++ptr) ;
	if (strncmp(ptr, "type=", 5))
	return -EINVAL;
	ptr += 5;
	for (; isspace(*ptr); ++ptr) ;
	for (i = 0; i < MTRR_NUM_TYPES; ++i) {
	if (strcmp(ptr, mtrr_strings[i]))
	continue;
	base >>= PAGE_SHIFT;
	size >>= PAGE_SHIFT;
	err =
	mtrr_add_page((unsigned long) base, (unsigned long) size, i,
	1);
	if (err < 0)
	return err;
	return len;
	}
	return -EINVAL;
	}

	static long
	mtrr_ioctl(struct file *file, unsigned int cmd, unsigned long __arg)
	{
	int err = 0;
	mtrr_type type;
	struct mtrr_sentry sentry;
	struct mtrr_gentry gentry;
	void __user arg = (void __user ) __arg;

	switch (cmd) {
	case MTRRIOC_ADD_ENTRY:
	case MTRRIOC_SET_ENTRY:
	case MTRRIOC_DEL_ENTRY:
	case MTRRIOC_KILL_ENTRY:
	case MTRRIOC_ADD_PAGE_ENTRY:
	case MTRRIOC_SET_PAGE_ENTRY:
	case MTRRIOC_DEL_PAGE_ENTRY:
	case MTRRIOC_KILL_PAGE_ENTRY:
	if (copy_from_user(&sentry, arg, sizeof sentry))
	return -EFAULT;
	break;
	case MTRRIOC_GET_ENTRY:
	case MTRRIOC_GET_PAGE_ENTRY:
	if (copy_from_user(&gentry, arg, sizeof gentry))
	return -EFAULT;
	break;
	#ifdef CONFIG_COMPAT
	case MTRRIOC32_ADD_ENTRY:
	case MTRRIOC32_SET_ENTRY:
	case MTRRIOC32_DEL_ENTRY:
	case MTRRIOC32_KILL_ENTRY:
	case MTRRIOC32_ADD_PAGE_ENTRY:
	case MTRRIOC32_SET_PAGE_ENTRY:
	case MTRRIOC32_DEL_PAGE_ENTRY:
	case MTRRIOC32_KILL_PAGE_ENTRY: {
	struct mtrr_sentry32 __user s32 = (struct mtrr_sentry32 __user )__arg;
	err = get_user(sentry.base, &s32->base);
	err \|= get_user(sentry.size, &s32->size);
	err \|= get_user(sentry.type, &s32->type);
	if (err)
	return err;
	break;
	}
	case MTRRIOC32_GET_ENTRY:
	case MTRRIOC32_GET_PAGE_ENTRY: {
	struct mtrr_gentry32 __user g32 = (struct mtrr_gentry32 __user )__arg;
	err = get_user(gentry.regnum, &g32->regnum);
	err \|= get_user(gentry.base, &g32->base);
	err \|= get_user(gentry.size, &g32->size);
	err \|= get_user(gentry.type, &g32->type);
	if (err)
	return err;
	break;
	}
	#endif
	}

	switch (cmd) {
	default:
	return -ENOTTY;
	case MTRRIOC_ADD_ENTRY:
	if (!capable(CAP_SYS_ADMIN))
	return -EPERM;
	err =
	mtrr_file_add(sentry.base, sentry.size, sentry.type, 1,
	file, 0);
	break;
	case MTRRIOC_SET_ENTRY:
	if (!capable(CAP_SYS_ADMIN))
	return -EPERM;
	err = mtrr_add(sentry.base, sentry.size, sentry.type, 0);
	break;
	case MTRRIOC_DEL_ENTRY:
	if (!capable(CAP_SYS_ADMIN))
	return -EPERM;
	err = mtrr_file_del(sentry.base, sentry.size, file, 0);
	break;
	case MTRRIOC_KILL_ENTRY:
	if (!capable(CAP_SYS_ADMIN))
	return -EPERM;
	err = mtrr_del(-1, sentry.base, sentry.size);
	break;
	case MTRRIOC_GET_ENTRY:
	if (gentry.regnum >= num_var_ranges)
	return -EINVAL;
	mtrr_if->get(gentry.regnum, &gentry.base, &gentry.size, &type);

	/* Hide entries that go above 4GB */
	if (gentry.base + gentry.size > 0x100000
	\|\| gentry.size == 0x100000)
	gentry.base = gentry.size = gentry.type = 0;
	else {
	gentry.base <<= PAGE_SHIFT;
	gentry.size <<= PAGE_SHIFT;
	gentry.type = type;
	}

	break;
	case MTRRIOC_ADD_PAGE_ENTRY:
	if (!capable(CAP_SYS_ADMIN))
	return -EPERM;
	err =
	mtrr_file_add(sentry.base, sentry.size, sentry.type, 1,
	file, 1);
	break;
	case MTRRIOC_SET_PAGE_ENTRY:
	if (!capable(CAP_SYS_ADMIN))
	return -EPERM;
	err = mtrr_add_page(sentry.base, sentry.size, sentry.type, 0);
	break;
	case MTRRIOC_DEL_PAGE_ENTRY:
	if (!capable(CAP_SYS_ADMIN))
	return -EPERM;
	err = mtrr_file_del(sentry.base, sentry.size, file, 1);
	break;
	case MTRRIOC_KILL_PAGE_ENTRY:
	if (!capable(CAP_SYS_ADMIN))
	return -EPERM;
	err = mtrr_del_page(-1, sentry.base, sentry.size);
	break;
	case MTRRIOC_GET_PAGE_ENTRY:
	if (gentry.regnum >= num_var_ranges)
	return -EINVAL;
	mtrr_if->get(gentry.regnum, &gentry.base, &gentry.size, &type);
	gentry.type = type;
	break;
	}

	if (err)
	return err;

	switch(cmd) {
	case MTRRIOC_GET_ENTRY:
	case MTRRIOC_GET_PAGE_ENTRY:
	if (copy_to_user(arg, &gentry, sizeof gentry))
	err = -EFAULT;
	break;
	#ifdef CONFIG_COMPAT
	case MTRRIOC32_GET_ENTRY:
	case MTRRIOC32_GET_PAGE_ENTRY: {
	struct mtrr_gentry32 __user g32 = (struct mtrr_gentry32 __user )__arg;
	err = put_user(gentry.base, &g32->base);
	err \|= put_user(gentry.size, &g32->size);
	err \|= put_user(gentry.regnum, &g32->regnum);
	err \|= put_user(gentry.type, &g32->type);
	break;
	}
	#endif
	}
	return err;
	}

	static int
	mtrr_close(struct inode ino, struct file file)
	{
	int i, max;
	unsigned int *fcount = FILE_FCOUNT(file);

	if (fcount != NULL) {
	max = num_var_ranges;
	for (i = 0; i < max; ++i) {
	while (fcount[i] > 0) {
	mtrr_del(i, 0, 0);
	--fcount[i];
	}
	}
	kfree(fcount);
	FILE_FCOUNT(file) = NULL;
	}
	return single_release(ino, file);
	}

	static int mtrr_seq_show(struct seq_file seq, void offset);

	static int mtrr_open(struct inode inode, struct file file)
	{
	if (!mtrr_if)
	return -EIO;
	if (!mtrr_if->get)
	return -ENXIO;
	return single_open(file, mtrr_seq_show, NULL);
	}

	static struct file_operations mtrr_fops = {
	.owner = THIS_MODULE,
	.open = mtrr_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.write = mtrr_write,
	.unlocked_ioctl = mtrr_ioctl,
	.compat_ioctl = mtrr_ioctl,
	.release = mtrr_close,
	};


	static struct proc_dir_entry *proc_root_mtrr;


	static int mtrr_seq_show(struct seq_file seq, void offset)
	{
	char factor;
	int i, max, len;
	mtrr_type type;
	unsigned long base;
	unsigned int size;

	len = 0;
	max = num_var_ranges;
	for (i = 0; i < max; i++) {
	mtrr_if->get(i, &base, &size, &type);
	if (size == 0)
	usage_table[i] = 0;
	else {
	if (size < (0x100000 >> PAGE_SHIFT)) {
	/* less than 1MB */
	factor = 'K';
	size <<= PAGE_SHIFT - 10;
	} else {
	factor = 'M';
	size >>= 20 - PAGE_SHIFT;
	}
	/* RED-PEN: base can be > 32bit */
	len += seq_printf(seq,
	"reg%02i: base=0x%05lx000 (%4liMB), size=%4i%cB: %s, count=%d\n",
	i, base, base >> (20 - PAGE_SHIFT), size, factor,
	mtrr_attrib_to_str(type), usage_table[i]);
	}
	}
	return 0;
	}

	static int __init mtrr_if_init(void)
	{
	struct cpuinfo_x86 *c = &boot_cpu_data;

	if ((!cpu_has(c, X86_FEATURE_MTRR)) &&
	(!cpu_has(c, X86_FEATURE_K6_MTRR)) &&
	(!cpu_has(c, X86_FEATURE_CYRIX_ARR)) &&
	(!cpu_has(c, X86_FEATURE_CENTAUR_MCR)))
	return -ENODEV;

	proc_root_mtrr =
	create_proc_entry("mtrr", S_IWUSR \| S_IRUGO, &proc_root);
	if (proc_root_mtrr) {
	proc_root_mtrr->owner = THIS_MODULE;
	proc_root_mtrr->proc_fops = &mtrr_fops;
	}
	return 0;
	}

	arch_initcall(mtrr_if_init);
	#endif /* CONFIG_PROC_FS */