mtrr.c

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	if ( (base < lbase) && (base + size <= lbase) ) continue;
	/*  At this point we know there is some kind of overlap/enclosure  */
	if ( (base < lbase) || (base + size > lbase + lsize) )
	{
	    up(&main_lock);
	    printk (KERN_WARNING "mtrr: 0x%lx000,0x%lx000 overlaps existing"
		    " 0x%lx000,0x%lx000\n",
		    base, size, lbase, lsize);
	    return -EINVAL;
	}
	/*  New region is enclosed by an existing region  */
	if (ltype != type)
	{
	    if (type == MTRR_TYPE_UNCACHABLE) continue;
	    up(&main_lock);
	    printk ( "mtrr: type mismatch for %lx000,%lx000 old: %s new: %s\n",
		     base, size, attrib_to_str (ltype), attrib_to_str (type) );
	    return -EINVAL;
	}
	if (increment) ++usage_table[i];
	compute_ascii ();
	up(&main_lock);
	return i;
    }
    /*  Search for an empty MTRR  */
    i = (*get_free_region) (base, size);
    if (i < 0)
    {
	up(&main_lock);
	printk ("mtrr: no more MTRRs available\n");
	return i;
    }
    set_mtrr (i, base, size, type);
    usage_table[i] = 1;
    compute_ascii ();
    up(&main_lock);
    return i;
}   /*  End Function mtrr_add_page  */

/**
 *	mtrr_add - Add a memory type region
 *	@base: Physical base address of region
 *	@size: Physical size of region
 *	@type: Type of MTRR desired
 *	@increment: If this is true do usage counting on the region
 *
 *	Memory type region registers control the caching on newer Intel and
 *	non Intel processors. This function allows drivers to request an
 *	MTRR is added. The details and hardware specifics of each processor's
 *	implementation are hidden from the caller, but nevertheless the 
 *	caller should expect to need to provide a power of two size on an
 *	equivalent power of two boundary.
 *
 *	If the region cannot be added either because all regions are in use
 *	or the CPU cannot support it a negative value is returned. On success
 *	the register number for this entry is returned, but should be treated
 *	as a cookie only.
 *
 *	On a multiprocessor machine the changes are made to all processors.
 *	This is required on x86 by the Intel processors.
 *
 *	The available types are
 *
 *	%MTRR_TYPE_UNCACHEABLE	-	No caching
 *
 *	%MTRR_TYPE_WRITEBACK	-	Write data back in bursts whenever
 *
 *	%MTRR_TYPE_WRCOMB	-	Write data back soon but allow bursts
 *
 *	%MTRR_TYPE_WRTHROUGH	-	Cache reads but not writes
 *
 *	BUGS: Needs a quiet flag for the cases where drivers do not mind
 *	failures and do not wish system log messages to be sent.
 */

int mtrr_add(unsigned long base, unsigned long size, unsigned int type, char increment)
{
/*  [SUMMARY] Add an MTRR entry.
    <base> The starting (base) address of the region.
    <size> The size (in bytes) of the region.
    <type> The type of the new region.
    <increment> If true and the region already exists, the usage count will be
    incremented.
    [RETURNS] The MTRR register on success, else a negative number indicating
    the error code.
*/

    if ( (base & (PAGE_SIZE - 1)) || (size & (PAGE_SIZE - 1)) )
    {
	printk ("mtrr: size and base must be multiples of 4 kiB\n");
	printk ("mtrr: size: 0x%lx  base: 0x%lx\n", size, base);
	return -EINVAL;
    }
    return mtrr_add_page(base >> PAGE_SHIFT, size >> PAGE_SHIFT, type, increment);
}   /*  End Function mtrr_add  */

/**
 *	mtrr_del_page - delete a memory type region
 *	@reg: Register returned by mtrr_add
 *	@base: Physical base address
 *	@size: Size of region
 *
 *	If register is supplied then base and size are ignored. This is
 *	how drivers should call it.
 *
 *	Releases an MTRR region. If the usage count drops to zero the 
 *	register is freed and the region returns to default state.
 *	On success the register is returned, on failure a negative error
 *	code.
 */
 
int mtrr_del_page (int reg, unsigned long base, unsigned long size)
/*  [SUMMARY] Delete MTRR/decrement usage count.
    <reg> The register. If this is less than 0 then <<base>> and <<size>> must
    be supplied.
    <base> The base address of the region. This is ignored if <<reg>> is >= 0.
    <size> The size of the region. This is ignored if <<reg>> is >= 0.
    [RETURNS] The register on success, else a negative number indicating
    the error code.
    [NOTE] This routine uses a spinlock.
*/
{
    int i, max;
    mtrr_type ltype;
    unsigned long lbase, lsize;

    if ( mtrr_if == MTRR_IF_NONE ) return -ENXIO;

    max = get_num_var_ranges ();
    down (&main_lock);
    if (reg < 0)
    {
	/*  Search for existing MTRR  */
	for (i = 0; i < max; ++i)
	{
	    (*get_mtrr) (i, &lbase, &lsize, &ltype);
	    if (lbase == base && lsize == size)
	    {
		reg = i;
		break;
	    }
	}
	if (reg < 0)
	{
	    up(&main_lock);
	    printk ("mtrr: no MTRR for %lx000,%lx000 found\n", base, size);
	    return -EINVAL;
	}
    }
    if (reg >= max)
    {
	up (&main_lock);
	printk ("mtrr: register: %d too big\n", reg);
	return -EINVAL;
    }
    if ( mtrr_if == MTRR_IF_CYRIX_ARR )
    {
	if ( (reg == 3) && arr3_protected )
	{
	    up (&main_lock);
	    printk ("mtrr: ARR3 cannot be changed\n");
	    return -EINVAL;
	}
    }
    (*get_mtrr) (reg, &lbase, &lsize, &ltype);
    if (lsize < 1)
    {
	up (&main_lock);
	printk ("mtrr: MTRR %d not used\n", reg);
	return -EINVAL;
    }
    if (usage_table[reg] < 1)
    {
	up (&main_lock);
	printk ("mtrr: reg: %d has count=0\n", reg);
	return -EINVAL;
    }
    if (--usage_table[reg] < 1) set_mtrr (reg, 0, 0, 0);
    compute_ascii ();
    up (&main_lock);
    return reg;
}   /*  End Function mtrr_del_page  */

/**
 *	mtrr_del - delete a memory type region
 *	@reg: Register returned by mtrr_add
 *	@base: Physical base address
 *	@size: Size of region
 *
 *	If register is supplied then base and size are ignored. This is
 *	how drivers should call it.
 *
 *	Releases an MTRR region. If the usage count drops to zero the 
 *	register is freed and the region returns to default state.
 *	On success the register is returned, on failure a negative error
 *	code.
 */
 
int mtrr_del (int reg, unsigned long base, unsigned long size)
/*  [SUMMARY] Delete MTRR/decrement usage count.
    <reg> The register. If this is less than 0 then <<base>> and <<size>> must
    be supplied.
    <base> The base address of the region. This is ignored if <<reg>> is >= 0.
    <size> The size of the region. This is ignored if <<reg>> is >= 0.
    [RETURNS] The register on success, else a negative number indicating
    the error code.
*/
{
    if ( (base & (PAGE_SIZE - 1)) || (size & (PAGE_SIZE - 1)) )
    {
	printk ("mtrr: size and base must be multiples of 4 kiB\n");
	printk ("mtrr: size: 0x%lx  base: 0x%lx\n", size, base);
	return -EINVAL;
    }
    return mtrr_del_page(reg, base >> PAGE_SHIFT, size >> PAGE_SHIFT);
}

#ifdef USERSPACE_INTERFACE

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->private_data;

    max = get_num_var_ranges ();
    if (fcount == NULL)
    {
	if ( ( fcount = kmalloc (max * sizeof *fcount, GFP_KERNEL) ) == NULL )
	{
	    printk ("mtrr: could not allocate\n");
	    return -ENOMEM;
	}
	memset (fcount, 0, max * sizeof *fcount);
	file->private_data = fcount;
    }
    if (!page) {
	if ( (base & (PAGE_SIZE - 1)) || (size & (PAGE_SIZE - 1)) )
	{
	    printk ("mtrr: size and base must be multiples of 4 kiB\n");
	    printk ("mtrr: size: 0x%lx  base: 0x%lx\n", size, base);
	    return -EINVAL;
	}
	base >>= PAGE_SHIFT;
	size >>= PAGE_SHIFT;
    }
    reg = mtrr_add_page (base, size, type, 1);
    if (reg >= 0) ++fcount[reg];
    return reg;
}   /*  End Function mtrr_file_add  */

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

    if (!page) {
	if ( (base & (PAGE_SIZE - 1)) || (size & (PAGE_SIZE - 1)) )
	{
	    printk ("mtrr: size and base must be multiples of 4 kiB\n");
	    printk ("mtrr: size: 0x%lx  base: 0x%lx\n", size, base);
	    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;
}   /*  End Function mtrr_file_del  */

static ssize_t mtrr_read (struct file *file, char *buf, size_t len,
			  loff_t *ppos)
{
    if (*ppos >= ascii_buf_bytes) return 0;
    if (*ppos + len > ascii_buf_bytes) len = ascii_buf_bytes - *ppos;
    if ( copy_to_user (buf, ascii_buffer + *ppos, len) ) return -EFAULT;
    *ppos += len;
    return len;
}   /*  End Function mtrr_read  */

static ssize_t mtrr_write (struct file *file, const char *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];

    if ( !suser () ) return -EPERM;
    /*  Can't seek (pwrite) on this device  */
    if (ppos != &file->f_pos) return -ESPIPE;
    memset (line, 0, LINE_SIZE);
    if (len > LINE_SIZE) len = LINE_SIZE;
    if ( copy_from_user (line, buf, len - 1) ) return -EFAULT;
    ptr = line + strlen (line) - 1;
    if (*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) )
    {
	printk ("mtrr: no \"base=\" in line: \"%s\"\n", line);
	return -EINVAL;
    }
    base = simple_strtoull (line + 5, &ptr, 0);
    for (; isspace (*ptr); ++ptr);
    if ( strncmp (ptr, "size=", 5) )
    {
	printk ("mtrr: no \"size=\" in line: \"%s\"\n", line);
	return -EINVAL;
    }
    size = simple_strtoull (ptr + 5, &ptr, 0);
    if ( (base & 0xfff) || (size & 0xfff) )
    {
	printk ("mtrr: size and base must be multiples of 4 kiB\n");
	printk ("mtrr: size: 0x%Lx  base: 0x%Lx\n", size, base);
	return -EINVAL;
    }
    for (; isspace (*ptr); ++ptr);
    if ( strncmp (ptr, "type=", 5) )
    {
	printk ("mtrr: no \"type=\" in line: \"%s\"\n", line);
	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;
    }
    printk ("mtrr: illegal type: \"%s\"\n", ptr);
    return -EINVAL;
}   /*  End Function mtrr_write  */

static int mtrr_ioctl (struct inode *inode, struct file *file,
		       unsigned int cmd, unsigned long arg)
{
    int err;
    mtrr_type type;
    struct mtrr_sentry sentry;
    struct mtrr_gentry gentry;

    switch (cmd)
    {
      default:
	return -ENOIOCTLCMD;
      case MTRRIOC_ADD_ENTRY:
	if ( !suser () ) return -EPERM;
	if ( copy_from_user (&sentry, (void *) arg, sizeof sentry) )
	    return -EFAULT;
	err = mtrr_file_add (sentry.base, sentry.size, sentry.type, 1, file, 0);
	if (err < 0) return err;
	break;
      case MTRRIOC_SET_ENTRY:
	if ( !suser () ) return -EPERM;
	if ( copy_from_user (&sentry, (void *) arg, sizeof sentry) )
	    return -EFAULT;
	err = mtrr_add (sentry.base, sentry.size, sentry.type, 0);
	if (err < 0) return err;
	break;
      case MTRRIOC_DEL_ENTRY:
	if ( !suser () ) return -EPERM;
	if ( copy_from_user (&sentry, (void *) arg, sizeof sentry) )
	    return -EFAULT;
	err = mtrr_file_del (sentry.base, sentry.size, file, 0);
	if (err < 0) return err;
	break;
      case MTRRIOC_KILL_ENTRY:
	if ( !suser () ) return -EPERM;
	if ( copy_from_user (&sentry, (void *) arg, sizeof sentry) )
	    return -EFAULT;
	err = mtrr_del (-1, sentry.base, sentry.size);
	if (err < 0) return err;
	break;
      case MTRRIOC_GET_ENTRY:
	if ( copy_from_user (&gentry, (void *) arg, sizeof gentry) )
	    return -EFAULT;
	if ( gentry.regnum >= get_num_var_ranges () ) return -EINVAL;
	(*get_mtrr) (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;
	}

	if ( copy_to_user ( (void *) arg, &gentry, sizeof gentry) )
	     return -EFAULT;
	break;
      case MTRRIOC_ADD_PAGE_ENTRY:
	if ( !suser () ) return -EPERM;
	if ( copy_from_user (&sentry, (void *) arg, sizeof sentry) )
	    return -EFAULT;
	err = mtrr_file_add (sentry.base, sentry.size, sentry.type, 1, file, 1);
	if (err < 0) return err;