281 строка
6.7 KiB
C
281 строка
6.7 KiB
C
/*
|
|
* Handle caching attributes in page tables (PAT)
|
|
*
|
|
* Authors: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
|
|
* Suresh B Siddha <suresh.b.siddha@intel.com>
|
|
*
|
|
* Interval tree (augmented rbtree) used to store the PAT memory type
|
|
* reservations.
|
|
*/
|
|
|
|
#include <linux/seq_file.h>
|
|
#include <linux/debugfs.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/rbtree_augmented.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/gfp.h>
|
|
|
|
#include <asm/pgtable.h>
|
|
#include <asm/pat.h>
|
|
|
|
#include "pat_internal.h"
|
|
|
|
/*
|
|
* The memtype tree keeps track of memory type for specific
|
|
* physical memory areas. Without proper tracking, conflicting memory
|
|
* types in different mappings can cause CPU cache corruption.
|
|
*
|
|
* The tree is an interval tree (augmented rbtree) with tree ordered
|
|
* on starting address. Tree can contain multiple entries for
|
|
* different regions which overlap. All the aliases have the same
|
|
* cache attributes of course.
|
|
*
|
|
* memtype_lock protects the rbtree.
|
|
*/
|
|
|
|
static struct rb_root memtype_rbroot = RB_ROOT;
|
|
|
|
static int is_node_overlap(struct memtype *node, u64 start, u64 end)
|
|
{
|
|
if (node->start >= end || node->end <= start)
|
|
return 0;
|
|
|
|
return 1;
|
|
}
|
|
|
|
static u64 get_subtree_max_end(struct rb_node *node)
|
|
{
|
|
u64 ret = 0;
|
|
if (node) {
|
|
struct memtype *data = rb_entry(node, struct memtype, rb);
|
|
ret = data->subtree_max_end;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static u64 compute_subtree_max_end(struct memtype *data)
|
|
{
|
|
u64 max_end = data->end, child_max_end;
|
|
|
|
child_max_end = get_subtree_max_end(data->rb.rb_right);
|
|
if (child_max_end > max_end)
|
|
max_end = child_max_end;
|
|
|
|
child_max_end = get_subtree_max_end(data->rb.rb_left);
|
|
if (child_max_end > max_end)
|
|
max_end = child_max_end;
|
|
|
|
return max_end;
|
|
}
|
|
|
|
RB_DECLARE_CALLBACKS(static, memtype_rb_augment_cb, struct memtype, rb,
|
|
u64, subtree_max_end, compute_subtree_max_end)
|
|
|
|
/* Find the first (lowest start addr) overlapping range from rb tree */
|
|
static struct memtype *memtype_rb_lowest_match(struct rb_root *root,
|
|
u64 start, u64 end)
|
|
{
|
|
struct rb_node *node = root->rb_node;
|
|
struct memtype *last_lower = NULL;
|
|
|
|
while (node) {
|
|
struct memtype *data = rb_entry(node, struct memtype, rb);
|
|
|
|
if (get_subtree_max_end(node->rb_left) > start) {
|
|
/* Lowest overlap if any must be on left side */
|
|
node = node->rb_left;
|
|
} else if (is_node_overlap(data, start, end)) {
|
|
last_lower = data;
|
|
break;
|
|
} else if (start >= data->start) {
|
|
/* Lowest overlap if any must be on right side */
|
|
node = node->rb_right;
|
|
} else {
|
|
break;
|
|
}
|
|
}
|
|
return last_lower; /* Returns NULL if there is no overlap */
|
|
}
|
|
|
|
enum {
|
|
MEMTYPE_EXACT_MATCH = 0,
|
|
MEMTYPE_END_MATCH = 1
|
|
};
|
|
|
|
static struct memtype *memtype_rb_match(struct rb_root *root,
|
|
u64 start, u64 end, int match_type)
|
|
{
|
|
struct memtype *match;
|
|
|
|
match = memtype_rb_lowest_match(root, start, end);
|
|
while (match != NULL && match->start < end) {
|
|
struct rb_node *node;
|
|
|
|
if ((match_type == MEMTYPE_EXACT_MATCH) &&
|
|
(match->start == start) && (match->end == end))
|
|
return match;
|
|
|
|
if ((match_type == MEMTYPE_END_MATCH) &&
|
|
(match->start < start) && (match->end == end))
|
|
return match;
|
|
|
|
node = rb_next(&match->rb);
|
|
if (node)
|
|
match = rb_entry(node, struct memtype, rb);
|
|
else
|
|
match = NULL;
|
|
}
|
|
|
|
return NULL; /* Returns NULL if there is no match */
|
|
}
|
|
|
|
static int memtype_rb_check_conflict(struct rb_root *root,
|
|
u64 start, u64 end,
|
|
enum page_cache_mode reqtype,
|
|
enum page_cache_mode *newtype)
|
|
{
|
|
struct rb_node *node;
|
|
struct memtype *match;
|
|
enum page_cache_mode found_type = reqtype;
|
|
|
|
match = memtype_rb_lowest_match(&memtype_rbroot, start, end);
|
|
if (match == NULL)
|
|
goto success;
|
|
|
|
if (match->type != found_type && newtype == NULL)
|
|
goto failure;
|
|
|
|
dprintk("Overlap at 0x%Lx-0x%Lx\n", match->start, match->end);
|
|
found_type = match->type;
|
|
|
|
node = rb_next(&match->rb);
|
|
while (node) {
|
|
match = rb_entry(node, struct memtype, rb);
|
|
|
|
if (match->start >= end) /* Checked all possible matches */
|
|
goto success;
|
|
|
|
if (is_node_overlap(match, start, end) &&
|
|
match->type != found_type) {
|
|
goto failure;
|
|
}
|
|
|
|
node = rb_next(&match->rb);
|
|
}
|
|
success:
|
|
if (newtype)
|
|
*newtype = found_type;
|
|
|
|
return 0;
|
|
|
|
failure:
|
|
pr_info("x86/PAT: %s:%d conflicting memory types %Lx-%Lx %s<->%s\n",
|
|
current->comm, current->pid, start, end,
|
|
cattr_name(found_type), cattr_name(match->type));
|
|
return -EBUSY;
|
|
}
|
|
|
|
static void memtype_rb_insert(struct rb_root *root, struct memtype *newdata)
|
|
{
|
|
struct rb_node **node = &(root->rb_node);
|
|
struct rb_node *parent = NULL;
|
|
|
|
while (*node) {
|
|
struct memtype *data = rb_entry(*node, struct memtype, rb);
|
|
|
|
parent = *node;
|
|
if (data->subtree_max_end < newdata->end)
|
|
data->subtree_max_end = newdata->end;
|
|
if (newdata->start <= data->start)
|
|
node = &((*node)->rb_left);
|
|
else if (newdata->start > data->start)
|
|
node = &((*node)->rb_right);
|
|
}
|
|
|
|
newdata->subtree_max_end = newdata->end;
|
|
rb_link_node(&newdata->rb, parent, node);
|
|
rb_insert_augmented(&newdata->rb, root, &memtype_rb_augment_cb);
|
|
}
|
|
|
|
int rbt_memtype_check_insert(struct memtype *new,
|
|
enum page_cache_mode *ret_type)
|
|
{
|
|
int err = 0;
|
|
|
|
err = memtype_rb_check_conflict(&memtype_rbroot, new->start, new->end,
|
|
new->type, ret_type);
|
|
|
|
if (!err) {
|
|
if (ret_type)
|
|
new->type = *ret_type;
|
|
|
|
new->subtree_max_end = new->end;
|
|
memtype_rb_insert(&memtype_rbroot, new);
|
|
}
|
|
return err;
|
|
}
|
|
|
|
struct memtype *rbt_memtype_erase(u64 start, u64 end)
|
|
{
|
|
struct memtype *data;
|
|
|
|
/*
|
|
* Since the memtype_rbroot tree allows overlapping ranges,
|
|
* rbt_memtype_erase() checks with EXACT_MATCH first, i.e. free
|
|
* a whole node for the munmap case. If no such entry is found,
|
|
* it then checks with END_MATCH, i.e. shrink the size of a node
|
|
* from the end for the mremap case.
|
|
*/
|
|
data = memtype_rb_match(&memtype_rbroot, start, end,
|
|
MEMTYPE_EXACT_MATCH);
|
|
if (!data) {
|
|
data = memtype_rb_match(&memtype_rbroot, start, end,
|
|
MEMTYPE_END_MATCH);
|
|
if (!data)
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
if (data->start == start) {
|
|
/* munmap: erase this node */
|
|
rb_erase_augmented(&data->rb, &memtype_rbroot,
|
|
&memtype_rb_augment_cb);
|
|
} else {
|
|
/* mremap: update the end value of this node */
|
|
rb_erase_augmented(&data->rb, &memtype_rbroot,
|
|
&memtype_rb_augment_cb);
|
|
data->end = start;
|
|
data->subtree_max_end = data->end;
|
|
memtype_rb_insert(&memtype_rbroot, data);
|
|
return NULL;
|
|
}
|
|
|
|
return data;
|
|
}
|
|
|
|
struct memtype *rbt_memtype_lookup(u64 addr)
|
|
{
|
|
return memtype_rb_lowest_match(&memtype_rbroot, addr, addr + PAGE_SIZE);
|
|
}
|
|
|
|
#if defined(CONFIG_DEBUG_FS)
|
|
int rbt_memtype_copy_nth_element(struct memtype *out, loff_t pos)
|
|
{
|
|
struct rb_node *node;
|
|
int i = 1;
|
|
|
|
node = rb_first(&memtype_rbroot);
|
|
while (node && pos != i) {
|
|
node = rb_next(node);
|
|
i++;
|
|
}
|
|
|
|
if (node) { /* pos == i */
|
|
struct memtype *this = rb_entry(node, struct memtype, rb);
|
|
*out = *this;
|
|
return 0;
|
|
} else {
|
|
return 1;
|
|
}
|
|
}
|
|
#endif
|