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-rw-r--r--arch/x86/mm/Makefile1
-rw-r--r--arch/x86/mm/pat.c209
-rw-r--r--arch/x86/mm/pat_internal.h20
-rw-r--r--arch/x86/mm/pat_rbtree.c271
4 files changed, 296 insertions, 205 deletions
diff --git a/arch/x86/mm/Makefile b/arch/x86/mm/Makefile
index 06630d26e56d..a4c768397baa 100644
--- a/arch/x86/mm/Makefile
+++ b/arch/x86/mm/Makefile
@@ -6,6 +6,7 @@ nostackp := $(call cc-option, -fno-stack-protector)
CFLAGS_physaddr.o := $(nostackp)
CFLAGS_setup_nx.o := $(nostackp)
+obj-$(CONFIG_X86_PAT) += pat_rbtree.o
obj-$(CONFIG_SMP) += tlb.o
obj-$(CONFIG_X86_32) += pgtable_32.o iomap_32.o
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 628e507b7936..951011166ef5 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -130,65 +130,7 @@ void pat_init(void)
#undef PAT
-/*
- * The global memtype list keeps track of memory type for specific
- * physical memory areas. Conflicting memory types in different
- * mappings can cause CPU cache corruption. To avoid this we keep track.
- *
- * The list is sorted based on starting address and can contain multiple
- * entries for each address (this allows reference counting for overlapping
- * areas). All the aliases have the same cache attributes of course.
- * Zero attributes are represented as holes.
- *
- * The data structure is a list that is also organized as an rbtree
- * sorted on the start address of memtype range.
- *
- * memtype_lock protects both the linear list and rbtree.
- */
-
-static struct rb_root memtype_rbroot = RB_ROOT;
-static LIST_HEAD(memtype_list);
-static DEFINE_SPINLOCK(memtype_lock); /* protects memtype list */
-
-static struct memtype *memtype_rb_search(struct rb_root *root, u64 start)
-{
- struct rb_node *node = root->rb_node;
- struct memtype *last_lower = NULL;
-
- while (node) {
- struct memtype *data = container_of(node, struct memtype, rb);
-
- if (data->start < start) {
- last_lower = data;
- node = node->rb_right;
- } else if (data->start > start) {
- node = node->rb_left;
- } else
- return data;
- }
-
- /* Will return NULL if there is no entry with its start <= start */
- return last_lower;
-}
-
-static void memtype_rb_insert(struct rb_root *root, struct memtype *data)
-{
- struct rb_node **new = &(root->rb_node);
- struct rb_node *parent = NULL;
-
- while (*new) {
- struct memtype *this = container_of(*new, struct memtype, rb);
-
- parent = *new;
- if (data->start <= this->start)
- new = &((*new)->rb_left);
- else if (data->start > this->start)
- new = &((*new)->rb_right);
- }
-
- rb_link_node(&data->rb, parent, new);
- rb_insert_color(&data->rb, root);
-}
+static DEFINE_SPINLOCK(memtype_lock); /* protects memtype accesses */
/*
* Does intersection of PAT memory type and MTRR memory type and returns
@@ -216,33 +158,6 @@ static unsigned long pat_x_mtrr_type(u64 start, u64 end, unsigned long req_type)
return req_type;
}
-static int
-chk_conflict(struct memtype *new, struct memtype *entry, unsigned long *type)
-{
- if (new->type != entry->type) {
- if (type) {
- new->type = entry->type;
- *type = entry->type;
- } else
- goto conflict;
- }
-
- /* check overlaps with more than one entry in the list */
- list_for_each_entry_continue(entry, &memtype_list, nd) {
- if (new->end <= entry->start)
- break;
- else if (new->type != entry->type)
- goto conflict;
- }
- return 0;
-
- conflict:
- printk(KERN_INFO "%s:%d conflicting memory types "
- "%Lx-%Lx %s<->%s\n", current->comm, current->pid, new->start,
- new->end, cattr_name(new->type), cattr_name(entry->type));
- return -EBUSY;
-}
-
static int pat_pagerange_is_ram(unsigned long start, unsigned long end)
{
int ram_page = 0, not_rampage = 0;
@@ -328,64 +243,6 @@ static int free_ram_pages_type(u64 start, u64 end)
return 0;
}
-static int memtype_check_insert(struct memtype *new, unsigned long *new_type)
-{
- struct memtype *entry;
- u64 start, end;
- unsigned long actual_type;
- struct list_head *where;
- int err = 0;
-
- start = new->start;
- end = new->end;
- actual_type = new->type;
-
- /* Search for existing mapping that overlaps the current range */
- where = NULL;
- list_for_each_entry(entry, &memtype_list, nd) {
- if (end <= entry->start) {
- where = entry->nd.prev;
- break;
- } else if (start <= entry->start) { /* end > entry->start */
- err = chk_conflict(new, entry, new_type);
- if (!err) {
- dprintk("Overlap at 0x%Lx-0x%Lx\n",
- entry->start, entry->end);
- where = entry->nd.prev;
- }
- break;
- } else if (start < entry->end) { /* start > entry->start */
- err = chk_conflict(new, entry, new_type);
- if (!err) {
- dprintk("Overlap at 0x%Lx-0x%Lx\n",
- entry->start, entry->end);
-
- /*
- * Move to right position in the linked
- * list to add this new entry
- */
- list_for_each_entry_continue(entry,
- &memtype_list, nd) {
- if (start <= entry->start) {
- where = entry->nd.prev;
- break;
- }
- }
- }
- break;
- }
- }
- if (!err) {
- if (where)
- list_add(&new->nd, where);
- else
- list_add_tail(&new->nd, &memtype_list);
-
- memtype_rb_insert(&memtype_rbroot, new);
- }
- return err;
-}
-
/*
* req_type typically has one of the:
* - _PAGE_CACHE_WB
@@ -459,7 +316,7 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
spin_lock(&memtype_lock);
- err = memtype_check_insert(new, new_type);
+ err = rbt_memtype_check_insert(new, new_type);
if (err) {
printk(KERN_INFO "reserve_memtype failed 0x%Lx-0x%Lx, "
"track %s, req %s\n",
@@ -481,7 +338,6 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
int free_memtype(u64 start, u64 end)
{
- struct memtype *entry, *saved_entry;
int err = -EINVAL;
int is_range_ram;
@@ -505,46 +361,7 @@ int free_memtype(u64 start, u64 end)
}
spin_lock(&memtype_lock);
-
- entry = memtype_rb_search(&memtype_rbroot, start);
- if (unlikely(entry == NULL))
- goto unlock_ret;
-
- /*
- * Saved entry points to an entry with start same or less than what
- * we searched for. Now go through the list in both directions to look
- * for the entry that matches with both start and end, with list stored
- * in sorted start address
- */
- saved_entry = entry;
- list_for_each_entry_from(entry, &memtype_list, nd) {
- if (entry->start == start && entry->end == end) {
- rb_erase(&entry->rb, &memtype_rbroot);
- list_del(&entry->nd);
- kfree(entry);
- err = 0;
- break;
- } else if (entry->start > start) {
- break;
- }
- }
-
- if (!err)
- goto unlock_ret;
-
- entry = saved_entry;
- list_for_each_entry_reverse(entry, &memtype_list, nd) {
- if (entry->start == start && entry->end == end) {
- rb_erase(&entry->rb, &memtype_rbroot);
- list_del(&entry->nd);
- kfree(entry);
- err = 0;
- break;
- } else if (entry->start < start) {
- break;
- }
- }
-unlock_ret:
+ err = rbt_memtype_erase(start, end);
spin_unlock(&memtype_lock);
if (err) {
@@ -593,7 +410,7 @@ static unsigned long lookup_memtype(u64 paddr)
spin_lock(&memtype_lock);
- entry = memtype_rb_search(&memtype_rbroot, paddr);
+ entry = rbt_memtype_lookup(paddr);
if (entry != NULL)
rettype = entry->type;
else
@@ -930,22 +747,6 @@ EXPORT_SYMBOL_GPL(pgprot_writecombine);
#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_X86_PAT)
-/* get Nth element of the linked list */
-static int copy_memtype_nth_element(struct memtype *out, loff_t pos)
-{
- struct memtype *list_node;
- int i = 1;
-
- list_for_each_entry(list_node, &memtype_list, nd) {
- if (pos == i) {
- *out = *list_node;
- return 0;
- }
- ++i;
- }
- return 1;
-}
-
static struct memtype *memtype_get_idx(loff_t pos)
{
struct memtype *print_entry;
@@ -956,7 +757,7 @@ static struct memtype *memtype_get_idx(loff_t pos)
return NULL;
spin_lock(&memtype_lock);
- ret = copy_memtype_nth_element(print_entry, pos);
+ ret = rbt_memtype_copy_nth_element(print_entry, pos);
spin_unlock(&memtype_lock);
if (!ret) {
diff --git a/arch/x86/mm/pat_internal.h b/arch/x86/mm/pat_internal.h
index 6c98780eb731..4f39eefa3e61 100644
--- a/arch/x86/mm/pat_internal.h
+++ b/arch/x86/mm/pat_internal.h
@@ -9,8 +9,8 @@ extern int pat_debug_enable;
struct memtype {
u64 start;
u64 end;
+ u64 subtree_max_end;
unsigned long type;
- struct list_head nd;
struct rb_node rb;
};
@@ -25,4 +25,22 @@ static inline char *cattr_name(unsigned long flags)
}
}
+#ifdef CONFIG_X86_PAT
+extern int rbt_memtype_check_insert(struct memtype *new,
+ unsigned long *new_type);
+extern int rbt_memtype_erase(u64 start, u64 end);
+extern struct memtype *rbt_memtype_lookup(u64 addr);
+extern int rbt_memtype_copy_nth_element(struct memtype *out, loff_t pos);
+#else
+static inline int rbt_memtype_check_insert(struct memtype *new,
+ unsigned long *new_type)
+{ return 0; }
+static inline int rbt_memtype_erase(u64 start, u64 end)
+{ return 0; }
+static inline struct memtype *rbt_memtype_lookup(u64 addr)
+{ return NULL; }
+static inline int rbt_memtype_copy_nth_element(struct memtype *out, loff_t pos)
+{ return 0; }
+#endif
+
#endif /* __PAT_INTERNAL_H_ */
diff --git a/arch/x86/mm/pat_rbtree.c b/arch/x86/mm/pat_rbtree.c
new file mode 100644
index 000000000000..9063f40b638b
--- /dev/null
+++ b/arch/x86/mm/pat_rbtree.c
@@ -0,0 +1,271 @@
+/*
+ * 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/module.h>
+#include <linux/rbtree.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 void memtype_rb_augment_cb(struct rb_node *node);
+static struct rb_root memtype_rbroot = RB_AUGMENT_ROOT(&memtype_rb_augment_cb);
+
+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 = container_of(node, struct memtype, rb);
+ ret = data->subtree_max_end;
+ }
+ return ret;
+}
+
+/* Update 'subtree_max_end' for a node, based on node and its children */
+static void update_node_max_end(struct rb_node *node)
+{
+ struct memtype *data;
+ u64 max_end, child_max_end;
+
+ if (!node)
+ return;
+
+ data = container_of(node, struct memtype, rb);
+ max_end = data->end;
+
+ child_max_end = get_subtree_max_end(node->rb_right);
+ if (child_max_end > max_end)
+ max_end = child_max_end;
+
+ child_max_end = get_subtree_max_end(node->rb_left);
+ if (child_max_end > max_end)
+ max_end = child_max_end;
+
+ data->subtree_max_end = max_end;
+}
+
+/* Update 'subtree_max_end' for a node and all its ancestors */
+static void update_path_max_end(struct rb_node *node)
+{
+ u64 old_max_end, new_max_end;
+
+ while (node) {
+ struct memtype *data = container_of(node, struct memtype, rb);
+
+ old_max_end = data->subtree_max_end;
+ update_node_max_end(node);
+ new_max_end = data->subtree_max_end;
+
+ if (new_max_end == old_max_end)
+ break;
+
+ node = rb_parent(node);
+ }
+}
+
+/* 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 = container_of(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 */
+}
+
+static struct memtype *memtype_rb_exact_match(struct rb_root *root,
+ u64 start, u64 end)
+{
+ struct memtype *match;
+
+ match = memtype_rb_lowest_match(root, start, end);
+ while (match != NULL && match->start < end) {
+ struct rb_node *node;
+
+ if (match->start == start && match->end == end)
+ return match;
+
+ node = rb_next(&match->rb);
+ if (node)
+ match = container_of(node, struct memtype, rb);
+ else
+ match = NULL;
+ }
+
+ return NULL; /* Returns NULL if there is no exact match */
+}
+
+static int memtype_rb_check_conflict(struct rb_root *root,
+ u64 start, u64 end,
+ unsigned long reqtype, unsigned long *newtype)
+{
+ struct rb_node *node;
+ struct memtype *match;
+ int 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 = container_of(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:
+ printk(KERN_INFO "%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_augment_cb(struct rb_node *node)
+{
+ if (node)
+ update_path_max_end(node);
+}
+
+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 = container_of(*node, struct memtype, rb);
+
+ parent = *node;
+ if (newdata->start <= data->start)
+ node = &((*node)->rb_left);
+ else if (newdata->start > data->start)
+ node = &((*node)->rb_right);
+ }
+
+ rb_link_node(&newdata->rb, parent, node);
+ rb_insert_color(&newdata->rb, root);
+}
+
+int rbt_memtype_check_insert(struct memtype *new, unsigned long *ret_type)
+{
+ int err = 0;
+
+ err = memtype_rb_check_conflict(&memtype_rbroot, new->start, new->end,
+ new->type, ret_type);
+
+ if (!err) {
+ new->type = *ret_type;
+ memtype_rb_insert(&memtype_rbroot, new);
+ }
+ return err;
+}
+
+int rbt_memtype_erase(u64 start, u64 end)
+{
+ struct memtype *data;
+
+ data = memtype_rb_exact_match(&memtype_rbroot, start, end);
+ if (!data)
+ return -EINVAL;
+
+ rb_erase(&data->rb, &memtype_rbroot);
+ return 0;
+}
+
+struct memtype *rbt_memtype_lookup(u64 addr)
+{
+ struct memtype *data;
+ data = memtype_rb_lowest_match(&memtype_rbroot, addr, addr + PAGE_SIZE);
+ return data;
+}
+
+#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 = container_of(node, struct memtype, rb);
+ *out = *this;
+ return 0;
+ } else {
+ return 1;
+ }
+}
+#endif
generated by cgit v1.2.3 (git 2.39.1) at 2024-10-17 00:31:53 +0000