/**
* mtrr_add_page - Add a memory type region
* @base: Physical base address of region in pages (in units of 4 kB!)
* @size: Physical size of region in pages (4 kB)
* @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_UNCACHABLE - No caching
*
* %MTRR_TYPE_WRBACK - 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_page(unsigned long base, unsigned long size,
unsigned int type, bool increment)
{
unsigned long lbase, lsize;
int i, replace, error;
mtrr_type ltype;
if (!mtrr_if)
return -ENXIO;
error = mtrr_if->validate_add_page(base, size, type);
if (error)
return error;
if (type >= MTRR_NUM_TYPES) {
pr_warning("mtrr: type: %u invalid\n", type);
return -EINVAL;
}
/* If the type is WC, check that this processor supports it */
if ((type == MTRR_TYPE_WRCOMB) && !have_wrcomb()) {
pr_warning("mtrr: your processor doesn't support write-combining\n");
return -ENOSYS;
}
if (!size) {
pr_warning("mtrr: zero sized request\n");
return -EINVAL;
}
if (base & size_or_mask || size & size_or_mask) {
pr_warning("mtrr: base or size exceeds the MTRR width\n");
return -EINVAL;
}
error = -EINVAL;
replace = -1;
/* No CPU hotplug when we change MTRR entries */
get_online_cpus();
/* Search for existing MTRR */
mutex_lock(&mtrr_mutex);
for (i = 0; i < num_var_ranges; ++i) {
mtrr_if->get(i, &lbase, &lsize, <ype);
if (!lsize || base > lbase + lsize - 1 ||
base + size - 1 < lbase)
continue;
/*
* At this point we know there is some kind of
* overlap/enclosure
*/
if (base < lbase || base + size - 1 > lbase + lsize - 1) {
if (base <= lbase &&
base + size - 1 >= lbase + lsize - 1) {
/* New region encloses an existing region */
if (type == ltype) {
replace = replace == -1 ? i : -2;
continue;
} else if (types_compatible(type, ltype))
continue;
}
pr_warning("mtrr: 0x%lx000,0x%lx000 overlaps existing"
" 0x%lx000,0x%lx000\n", base, size, lbase,
lsize);
goto out;
}
/* New region is enclosed by an existing region */
if (ltype != type) {
if (types_compatible(type, ltype))
continue;
pr_warning("mtrr: type mismatch for %lx000,%lx000 old: %s new: %s\n",
base, size, mtrr_attrib_to_str(ltype),
mtrr_attrib_to_str(type));
goto out;
}
if (increment)
++mtrr_usage_table[i];
error = i;
goto out;
}
/* Search for an empty MTRR */
i = mtrr_if->get_free_region(base, size, replace);
if (i >= 0) {
set_mtrr(i, base, size, type);
if (likely(replace < 0)) {
mtrr_usage_table[i] = 1;
} else {
mtrr_usage_table[i] = mtrr_usage_table[replace];
if (increment)
mtrr_usage_table[i]++;
if (unlikely(replace != i)) {
set_mtrr(replace, 0, 0, 0);
mtrr_usage_table[replace] = 0;
}
}
} else {
pr_info("mtrr: no more MTRRs available\n");
}
error = i;
out:
mutex_unlock(&mtrr_mutex);
put_online_cpus();
return error;
}
int mtrr_add_page(unsigned long base, unsigned long size,
unsigned int type, char increment)
{
int i;
mtrr_type ltype;
unsigned long lbase;
unsigned int lsize;
int error;
if (!mtrr_if)
return -ENXIO;
if ((error = mtrr_if->validate_add_page(base,size,type)))
return error;
if (type >= MTRR_NUM_TYPES) {
printk(KERN_WARNING "mtrr: type: %u invalid\n", type);
return -EINVAL;
}
/* If the type is WC, check that this processor supports it */
if ((type == MTRR_TYPE_WRCOMB) && !have_wrcomb()) {
printk(KERN_WARNING
"mtrr: your processor doesn't support write-combining\n");
return -ENOSYS;
}
if (base & size_or_mask || size & size_or_mask) {
printk(KERN_WARNING "mtrr: base or size exceeds the MTRR width\n");
return -EINVAL;
}
error = -EINVAL;
/* Search for existing MTRR */
down(&main_lock);
for (i = 0; i < num_var_ranges; ++i) {
mtrr_if->get(i, &lbase, &lsize, <ype);
if (base >= lbase + lsize)
continue;
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)) {
printk(KERN_WARNING
"mtrr: 0x%lx000,0x%lx000 overlaps existing"
" 0x%lx000,0x%x000\n", base, size, lbase,
lsize);
goto out;
}
/* New region is enclosed by an existing region */
if (ltype != type) {
if (type == MTRR_TYPE_UNCACHABLE)
continue;
printk (KERN_WARNING "mtrr: type mismatch for %lx000,%lx000 old: %s new: %s\n",
base, size, mtrr_attrib_to_str(ltype),
mtrr_attrib_to_str(type));
goto out;
}
if (increment)
++usage_table[i];
error = i;
goto out;
}
/* Search for an empty MTRR */
i = mtrr_if->get_free_region(base, size);
if (i >= 0) {
set_mtrr(i, base, size, type);
usage_table[i] = 1;
} else
printk(KERN_INFO "mtrr: no more MTRRs available\n");
error = i;
out:
up(&main_lock);
return error;
}
