#include <linux/gfp.h>
#include <linux/mm.h>
#include <linux/fs.h>
+#include <linux/rbtree.h>
#include <asm/cacheflush.h>
#include <asm/processor.h>
* areas). All the aliases have the same cache attributes of course.
* Zero attributes are represented as holes.
*
- * Currently the data structure is a list because the number of mappings
- * are expected to be relatively small. If this should be a problem
- * it could be changed to a rbtree or similar.
+ * The data structure is a list that is also organized as an rbtree
+ * sorted on the start address of memtype range.
*
- * memtype_lock protects the whole list.
+ * memtype_lock protects both the linear list and rbtree.
*/
struct memtype {
u64 end;
unsigned long type;
struct list_head nd;
+ struct rb_node rb;
};
+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);
+}
+
/*
* Does intersection of PAT memory type and MTRR memory type and returns
* the resulting memory type as PAT understands it.
return -EBUSY;
}
-static struct memtype *cached_entry;
-static u64 cached_start;
-
static int pat_pagerange_is_ram(unsigned long start, unsigned long end)
{
int ram_page = 0, not_rampage = 0;
}
/*
- * For RAM pages, mark the pages as non WB memory type using
- * PageNonWB (PG_arch_1). We allow only one set_memory_uc() or
- * set_memory_wc() on a RAM page at a time before marking it as WB again.
- * This is ok, because only one driver will be owning the page and
- * doing set_memory_*() calls.
+ * For RAM pages, we use page flags to mark the pages with appropriate type.
+ * Here we do two pass:
+ * - Find the memtype of all the pages in the range, look for any conflicts
+ * - In case of no conflicts, set the new memtype for pages in the range
*
- * For now, we use PageNonWB to track that the RAM page is being mapped
- * as non WB. In future, we will have to use one more flag
- * (or some other mechanism in page_struct) to distinguish between
- * UC and WC mapping.
+ * Caller must hold memtype_lock for atomicity.
*/
static int reserve_ram_pages_type(u64 start, u64 end, unsigned long req_type,
unsigned long *new_type)
{
struct page *page;
- u64 pfn, end_pfn;
+ u64 pfn;
+
+ if (req_type == _PAGE_CACHE_UC) {
+ /* We do not support strong UC */
+ WARN_ON_ONCE(1);
+ req_type = _PAGE_CACHE_UC_MINUS;
+ }
for (pfn = (start >> PAGE_SHIFT); pfn < (end >> PAGE_SHIFT); ++pfn) {
- page = pfn_to_page(pfn);
- if (page_mapped(page) || PageNonWB(page))
- goto out;
+ unsigned long type;
- SetPageNonWB(page);
+ page = pfn_to_page(pfn);
+ type = get_page_memtype(page);
+ if (type != -1) {
+ printk(KERN_INFO "reserve_ram_pages_type failed "
+ "0x%Lx-0x%Lx, track 0x%lx, req 0x%lx\n",
+ start, end, type, req_type);
+ if (new_type)
+ *new_type = type;
+
+ return -EBUSY;
+ }
}
- return 0;
-out:
- end_pfn = pfn;
- for (pfn = (start >> PAGE_SHIFT); pfn < end_pfn; ++pfn) {
+ if (new_type)
+ *new_type = req_type;
+
+ for (pfn = (start >> PAGE_SHIFT); pfn < (end >> PAGE_SHIFT); ++pfn) {
page = pfn_to_page(pfn);
- ClearPageNonWB(page);
+ set_page_memtype(page, req_type);
}
-
- return -EINVAL;
+ return 0;
}
static int free_ram_pages_type(u64 start, u64 end)
{
struct page *page;
- u64 pfn, end_pfn;
+ u64 pfn;
for (pfn = (start >> PAGE_SHIFT); pfn < (end >> PAGE_SHIFT); ++pfn) {
page = pfn_to_page(pfn);
- if (page_mapped(page) || !PageNonWB(page))
- goto out;
-
- ClearPageNonWB(page);
+ set_page_memtype(page, -1);
}
return 0;
-
-out:
- end_pfn = pfn;
- for (pfn = (start >> PAGE_SHIFT); pfn < end_pfn; ++pfn) {
- page = pfn_to_page(pfn);
- SetPageNonWB(page);
- }
- return -EINVAL;
}
/*
if (new_type) {
if (req_type == -1)
*new_type = _PAGE_CACHE_WB;
+ else if (req_type == _PAGE_CACHE_WC)
+ *new_type = _PAGE_CACHE_UC_MINUS;
else
*new_type = req_type & _PAGE_CACHE_MASK;
}
*new_type = actual_type;
is_range_ram = pat_pagerange_is_ram(start, end);
- if (is_range_ram == 1)
- return reserve_ram_pages_type(start, end, req_type,
- new_type);
- else if (is_range_ram < 0)
+ if (is_range_ram == 1) {
+
+ spin_lock(&memtype_lock);
+ err = reserve_ram_pages_type(start, end, req_type, new_type);
+ spin_unlock(&memtype_lock);
+
+ return err;
+ } else if (is_range_ram < 0) {
return -EINVAL;
+ }
new = kmalloc(sizeof(struct memtype), GFP_KERNEL);
if (!new)
spin_lock(&memtype_lock);
- if (cached_entry && start >= cached_start)
- entry = cached_entry;
- else
- entry = list_entry(&memtype_list, struct memtype, nd);
-
/* Search for existing mapping that overlaps the current range */
where = NULL;
- list_for_each_entry_continue(entry, &memtype_list, nd) {
+ list_for_each_entry(entry, &memtype_list, nd) {
if (end <= entry->start) {
where = entry->nd.prev;
- cached_entry = list_entry(where, struct memtype, nd);
break;
} else if (start <= entry->start) { /* end > entry->start */
err = chk_conflict(new, entry, new_type);
dprintk("Overlap at 0x%Lx-0x%Lx\n",
entry->start, entry->end);
where = entry->nd.prev;
- cached_entry = list_entry(where,
- struct memtype, nd);
}
break;
} else if (start < entry->end) { /* start > entry->start */
if (!err) {
dprintk("Overlap at 0x%Lx-0x%Lx\n",
entry->start, entry->end);
- cached_entry = list_entry(entry->nd.prev,
- struct memtype, nd);
/*
* Move to right position in the linked
return err;
}
- cached_start = start;
-
if (where)
list_add(&new->nd, where);
else
list_add_tail(&new->nd, &memtype_list);
+ memtype_rb_insert(&memtype_rbroot, new);
+
spin_unlock(&memtype_lock);
dprintk("reserve_memtype added 0x%Lx-0x%Lx, track %s, req %s, ret %s\n",
int free_memtype(u64 start, u64 end)
{
- struct memtype *entry;
+ struct memtype *entry, *saved_entry;
int err = -EINVAL;
int is_range_ram;
return 0;
is_range_ram = pat_pagerange_is_ram(start, end);
- if (is_range_ram == 1)
- return free_ram_pages_type(start, end);
- else if (is_range_ram < 0)
+ if (is_range_ram == 1) {
+
+ spin_lock(&memtype_lock);
+ err = free_ram_pages_type(start, end);
+ spin_unlock(&memtype_lock);
+
+ return err;
+ } else if (is_range_ram < 0) {
return -EINVAL;
+ }
spin_lock(&memtype_lock);
- list_for_each_entry(entry, &memtype_list, nd) {
+
+ 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) {
- if (cached_entry == entry || cached_start == start)
- cached_entry = NULL;
+ 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:
spin_unlock(&memtype_lock);
if (err) {
}
+/**
+ * lookup_memtype - Looksup the memory type for a physical address
+ * @paddr: physical address of which memory type needs to be looked up
+ *
+ * Only to be called when PAT is enabled
+ *
+ * Returns _PAGE_CACHE_WB, _PAGE_CACHE_WC, _PAGE_CACHE_UC_MINUS or
+ * _PAGE_CACHE_UC
+ */
+static unsigned long lookup_memtype(u64 paddr)
+{
+ int rettype = _PAGE_CACHE_WB;
+ struct memtype *entry;
+
+ if (is_ISA_range(paddr, paddr + PAGE_SIZE - 1))
+ return rettype;
+
+ if (pat_pagerange_is_ram(paddr, paddr + PAGE_SIZE)) {
+ struct page *page;
+ spin_lock(&memtype_lock);
+ page = pfn_to_page(paddr >> PAGE_SHIFT);
+ rettype = get_page_memtype(page);
+ spin_unlock(&memtype_lock);
+ /*
+ * -1 from get_page_memtype() implies RAM page is in its
+ * default state and not reserved, and hence of type WB
+ */
+ if (rettype == -1)
+ rettype = _PAGE_CACHE_WB;
+
+ return rettype;
+ }
+
+ spin_lock(&memtype_lock);
+
+ entry = memtype_rb_search(&memtype_rbroot, paddr);
+ if (entry != NULL)
+ rettype = entry->type;
+ else
+ rettype = _PAGE_CACHE_UC_MINUS;
+
+ spin_unlock(&memtype_lock);
+ return rettype;
+}
+
+/**
+ * io_reserve_memtype - Request a memory type mapping for a region of memory
+ * @start: start (physical address) of the region
+ * @end: end (physical address) of the region
+ * @type: A pointer to memtype, with requested type. On success, requested
+ * or any other compatible type that was available for the region is returned
+ *
+ * On success, returns 0
+ * On failure, returns non-zero
+ */
+int io_reserve_memtype(resource_size_t start, resource_size_t end,
+ unsigned long *type)
+{
+ resource_size_t size = end - start;
+ unsigned long req_type = *type;
+ unsigned long new_type;
+ int ret;
+
+ WARN_ON_ONCE(iomem_map_sanity_check(start, size));
+
+ ret = reserve_memtype(start, end, req_type, &new_type);
+ if (ret)
+ goto out_err;
+
+ if (!is_new_memtype_allowed(start, size, req_type, new_type))
+ goto out_free;
+
+ if (kernel_map_sync_memtype(start, size, new_type) < 0)
+ goto out_free;
+
+ *type = new_type;
+ return 0;
+
+out_free:
+ free_memtype(start, end);
+ ret = -EBUSY;
+out_err:
+ return ret;
+}
+
+/**
+ * io_free_memtype - Release a memory type mapping for a region of memory
+ * @start: start (physical address) of the region
+ * @end: end (physical address) of the region
+ */
+void io_free_memtype(resource_size_t start, resource_size_t end)
+{
+ free_memtype(start, end);
+}
+
pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
unsigned long size, pgprot_t vma_prot)
{
{
unsigned long id_sz;
- if (!pat_enabled || base >= __pa(high_memory))
+ if (base >= __pa(high_memory))
return 0;
id_sz = (__pa(high_memory) < base + size) ?
is_ram = pat_pagerange_is_ram(paddr, paddr + size);
/*
- * reserve_pfn_range() doesn't support RAM pages. Maintain the current
- * behavior with RAM pages by returning success.
+ * reserve_pfn_range() for RAM pages. We do not refcount to keep
+ * track of number of mappings of RAM pages. We can assert that
+ * the type requested matches the type of first page in the range.
*/
- if (is_ram != 0)
+ if (is_ram) {
+ if (!pat_enabled)
+ return 0;
+
+ flags = lookup_memtype(paddr);
+ if (want_flags != flags) {
+ printk(KERN_WARNING
+ "%s:%d map pfn RAM range req %s for %Lx-%Lx, got %s\n",
+ current->comm, current->pid,
+ cattr_name(want_flags),
+ (unsigned long long)paddr,
+ (unsigned long long)(paddr + size),
+ cattr_name(flags));
+ *vma_prot = __pgprot((pgprot_val(*vma_prot) &
+ (~_PAGE_CACHE_MASK)) |
+ flags);
+ }
return 0;
+ }
ret = reserve_memtype(paddr, paddr + size, want_flags, &flags);
if (ret)
unsigned long vma_size = vma->vm_end - vma->vm_start;
pgprot_t pgprot;
- if (!pat_enabled)
- return 0;
-
- /*
- * For now, only handle remap_pfn_range() vmas where
- * is_linear_pfn_mapping() == TRUE. Handling of
- * vm_insert_pfn() is TBD.
- */
if (is_linear_pfn_mapping(vma)) {
/*
* reserve the whole chunk covered by vma. We need the
int track_pfn_vma_new(struct vm_area_struct *vma, pgprot_t *prot,
unsigned long pfn, unsigned long size)
{
+ unsigned long flags;
resource_size_t paddr;
unsigned long vma_size = vma->vm_end - vma->vm_start;
- if (!pat_enabled)
- return 0;
-
- /*
- * For now, only handle remap_pfn_range() vmas where
- * is_linear_pfn_mapping() == TRUE. Handling of
- * vm_insert_pfn() is TBD.
- */
if (is_linear_pfn_mapping(vma)) {
/* reserve the whole chunk starting from vm_pgoff */
paddr = (resource_size_t)vma->vm_pgoff << PAGE_SHIFT;
return reserve_pfn_range(paddr, vma_size, prot, 0);
}
+ if (!pat_enabled)
+ return 0;
+
+ /* for vm_insert_pfn and friends, we set prot based on lookup */
+ flags = lookup_memtype(pfn << PAGE_SHIFT);
+ *prot = __pgprot((pgprot_val(vma->vm_page_prot) & (~_PAGE_CACHE_MASK)) |
+ flags);
+
return 0;
}
resource_size_t paddr;
unsigned long vma_size = vma->vm_end - vma->vm_start;
- if (!pat_enabled)
- return;
-
- /*
- * For now, only handle remap_pfn_range() vmas where
- * is_linear_pfn_mapping() == TRUE. Handling of
- * vm_insert_pfn() is TBD.
- */
if (is_linear_pfn_mapping(vma)) {
/* free the whole chunk starting from vm_pgoff */
paddr = (resource_size_t)vma->vm_pgoff << PAGE_SHIFT;
return 0;
}
-static struct seq_operations memtype_seq_ops = {
+static const struct seq_operations memtype_seq_ops = {
.start = memtype_seq_start,
.next = memtype_seq_next,
.stop = memtype_seq_stop,
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