1 files changed, 436 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_vma_manager.c b/drivers/gpu/drm/drm_vma_manager.c
new file mode 100644
index 000000000000..63b471205072
--- /dev/null
+++ b/drivers/gpu/drm/drm_vma_manager.c
@@ -0,0 +1,436 @@
+/*
+ * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
+ * Copyright (c) 2012 David Airlie <airlied@linux.ie>
+ * Copyright (c) 2013 David Herrmann <dh.herrmann@gmail.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <drm/drmP.h>
+#include <drm/drm_mm.h>
+#include <drm/drm_vma_manager.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/rbtree.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+
+/**
+ * DOC: vma offset manager
+ *
+ * The vma-manager is responsible to map arbitrary driver-dependent memory
+ * regions into the linear user address-space. It provides offsets to the
+ * caller which can then be used on the address_space of the drm-device. It
+ * takes care to not overlap regions, size them appropriately and to not
+ * confuse mm-core by inconsistent fake vm_pgoff fields.
+ * Drivers shouldn't use this for object placement in VMEM. This manager should
+ * only be used to manage mappings into linear user-space VMs.
+ *
+ * We use drm_mm as backend to manage object allocations. But it is highly
+ * optimized for alloc/free calls, not lookups. Hence, we use an rb-tree to
+ * speed up offset lookups.
+ *
+ * You must not use multiple offset managers on a single address_space.
+ * Otherwise, mm-core will be unable to tear down memory mappings as the VM will
+ * no longer be linear. Please use VM_NONLINEAR in that case and implement your
+ * own offset managers.
+ *
+ * This offset manager works on page-based addresses. That is, every argument
+ * and return code (with the exception of drm_vma_node_offset_addr()) is given
+ * in number of pages, not number of bytes. That means, object sizes and offsets
+ * must always be page-aligned (as usual).
+ * If you want to get a valid byte-based user-space address for a given offset,
+ * please see drm_vma_node_offset_addr().
+ *
+ * Additionally to offset management, the vma offset manager also handles access
+ * management. For every open-file context that is allowed to access a given
+ * node, you must call drm_vma_node_allow(). Otherwise, an mmap() call on this
+ * open-file with the offset of the node will fail with -EACCES. To revoke
+ * access again, use drm_vma_node_revoke(). However, the caller is responsible
+ * for destroying already existing mappings, if required.
+ */
+
+/**
+ * drm_vma_offset_manager_init - Initialize new offset-manager
+ * @mgr: Manager object
+ * @page_offset: Offset of available memory area (page-based)
+ * @size: Size of available address space range (page-based)
+ *
+ * Initialize a new offset-manager. The offset and area size available for the
+ * manager are given as @page_offset and @size. Both are interpreted as
+ * page-numbers, not bytes.
+ *
+ * Adding/removing nodes from the manager is locked internally and protected
+ * against concurrent access. However, node allocation and destruction is left
+ * for the caller. While calling into the vma-manager, a given node must
+ * always be guaranteed to be referenced.
+ */
+void drm_vma_offset_manager_init(struct drm_vma_offset_manager *mgr,
+				 unsigned long page_offset, unsigned long size)
+{
+	rwlock_init(&mgr->vm_lock);
+	mgr->vm_addr_space_rb = RB_ROOT;
+	drm_mm_init(&mgr->vm_addr_space_mm, page_offset, size);
+}
+EXPORT_SYMBOL(drm_vma_offset_manager_init);
+
+/**
+ * drm_vma_offset_manager_destroy() - Destroy offset manager
+ * @mgr: Manager object
+ *
+ * Destroy an object manager which was previously created via
+ * drm_vma_offset_manager_init(). The caller must remove all allocated nodes
+ * before destroying the manager. Otherwise, drm_mm will refuse to free the
+ * requested resources.
+ *
+ * The manager must not be accessed after this function is called.
+ */
+void drm_vma_offset_manager_destroy(struct drm_vma_offset_manager *mgr)
+{
+	/* take the lock to protect against buggy drivers */
+	write_lock(&mgr->vm_lock);
+	drm_mm_takedown(&mgr->vm_addr_space_mm);
+	write_unlock(&mgr->vm_lock);
+}
+EXPORT_SYMBOL(drm_vma_offset_manager_destroy);
+
+/**
+ * drm_vma_offset_lookup() - Find node in offset space
+ * @mgr: Manager object
+ * @start: Start address for object (page-based)
+ * @pages: Size of object (page-based)
+ *
+ * Find a node given a start address and object size. This returns the _best_
+ * match for the given node. That is, @start may point somewhere into a valid
+ * region and the given node will be returned, as long as the node spans the
+ * whole requested area (given the size in number of pages as @pages).
+ *
+ * RETURNS:
+ * Returns NULL if no suitable node can be found. Otherwise, the best match
+ * is returned. It's the caller's responsibility to make sure the node doesn't
+ * get destroyed before the caller can access it.
+ */
+struct drm_vma_offset_node *drm_vma_offset_lookup(struct drm_vma_offset_manager *mgr,
+						  unsigned long start,
+						  unsigned long pages)
+{
+	struct drm_vma_offset_node *node;
+
+	read_lock(&mgr->vm_lock);
+	node = drm_vma_offset_lookup_locked(mgr, start, pages);
+	read_unlock(&mgr->vm_lock);
+
+	return node;
+}
+EXPORT_SYMBOL(drm_vma_offset_lookup);
+
+/**
+ * drm_vma_offset_lookup_locked() - Find node in offset space
+ * @mgr: Manager object
+ * @start: Start address for object (page-based)
+ * @pages: Size of object (page-based)
+ *
+ * Same as drm_vma_offset_lookup() but requires the caller to lock offset lookup
+ * manually. See drm_vma_offset_lock_lookup() for an example.
+ *
+ * RETURNS:
+ * Returns NULL if no suitable node can be found. Otherwise, the best match
+ * is returned.
+ */
+struct drm_vma_offset_node *drm_vma_offset_lookup_locked(struct drm_vma_offset_manager *mgr,
+							 unsigned long start,
+							 unsigned long pages)
+{
+	struct drm_vma_offset_node *node, *best;
+	struct rb_node *iter;
+	unsigned long offset;
+
+	iter = mgr->vm_addr_space_rb.rb_node;
+	best = NULL;
+
+	while (likely(iter)) {
+		node = rb_entry(iter, struct drm_vma_offset_node, vm_rb);
+		offset = node->vm_node.start;
+		if (start >= offset) {
+			iter = iter->rb_right;
+			best = node;
+			if (start == offset)
+				break;
+		} else {
+			iter = iter->rb_left;
+		}
+	}
+
+	/* verify that the node spans the requested area */
+	if (best) {
+		offset = best->vm_node.start + best->vm_node.size;
+		if (offset < start + pages)
+			best = NULL;
+	}
+
+	return best;
+}
+EXPORT_SYMBOL(drm_vma_offset_lookup_locked);
+
+/* internal helper to link @node into the rb-tree */
+static void _drm_vma_offset_add_rb(struct drm_vma_offset_manager *mgr,
+				   struct drm_vma_offset_node *node)
+{
+	struct rb_node **iter = &mgr->vm_addr_space_rb.rb_node;
+	struct rb_node *parent = NULL;
+	struct drm_vma_offset_node *iter_node;
+
+	while (likely(*iter)) {
+		parent = *iter;
+		iter_node = rb_entry(*iter, struct drm_vma_offset_node, vm_rb);
+
+		if (node->vm_node.start < iter_node->vm_node.start)
+			iter = &(*iter)->rb_left;
+		else if (node->vm_node.start > iter_node->vm_node.start)
+			iter = &(*iter)->rb_right;
+		else
+			BUG();
+	}
+
+	rb_link_node(&node->vm_rb, parent, iter);
+	rb_insert_color(&node->vm_rb, &mgr->vm_addr_space_rb);
+}
+
+/**
+ * drm_vma_offset_add() - Add offset node to manager
+ * @mgr: Manager object
+ * @node: Node to be added
+ * @pages: Allocation size visible to user-space (in number of pages)
+ *
+ * Add a node to the offset-manager. If the node was already added, this does
+ * nothing and return 0. @pages is the size of the object given in number of
+ * pages.
+ * After this call succeeds, you can access the offset of the node until it
+ * is removed again.
+ *
+ * If this call fails, it is safe to retry the operation or call
+ * drm_vma_offset_remove(), anyway. However, no cleanup is required in that
+ * case.
+ *
+ * @pages is not required to be the same size as the underlying memory object
+ * that you want to map. It only limits the size that user-space can map into
+ * their address space.
+ *
+ * RETURNS:
+ * 0 on success, negative error code on failure.
+ */
+int drm_vma_offset_add(struct drm_vma_offset_manager *mgr,
+		       struct drm_vma_offset_node *node, unsigned long pages)
+{
+	int ret;
+
+	write_lock(&mgr->vm_lock);
+
+	if (drm_mm_node_allocated(&node->vm_node)) {
+		ret = 0;
+		goto out_unlock;
+	}
+
+	ret = drm_mm_insert_node(&mgr->vm_addr_space_mm, &node->vm_node,
+				 pages, 0, DRM_MM_SEARCH_DEFAULT);
+	if (ret)
+		goto out_unlock;
+
+	_drm_vma_offset_add_rb(mgr, node);
+
+out_unlock:
+	write_unlock(&mgr->vm_lock);
+	return ret;
+}
+EXPORT_SYMBOL(drm_vma_offset_add);
+
+/**
+ * drm_vma_offset_remove() - Remove offset node from manager
+ * @mgr: Manager object
+ * @node: Node to be removed
+ *
+ * Remove a node from the offset manager. If the node wasn't added before, this
+ * does nothing. After this call returns, the offset and size will be 0 until a
+ * new offset is allocated via drm_vma_offset_add() again. Helper functions like
+ * drm_vma_node_start() and drm_vma_node_offset_addr() will return 0 if no
+ * offset is allocated.
+ */
+void drm_vma_offset_remove(struct drm_vma_offset_manager *mgr,
+			   struct drm_vma_offset_node *node)
+{
+	write_lock(&mgr->vm_lock);
+
+	if (drm_mm_node_allocated(&node->vm_node)) {
+		rb_erase(&node->vm_rb, &mgr->vm_addr_space_rb);
+		drm_mm_remove_node(&node->vm_node);
+		memset(&node->vm_node, 0, sizeof(node->vm_node));
+	}
+
+	write_unlock(&mgr->vm_lock);
+}
+EXPORT_SYMBOL(drm_vma_offset_remove);
+
+/**
+ * drm_vma_node_allow - Add open-file to list of allowed users
+ * @node: Node to modify
+ * @filp: Open file to add
+ *
+ * Add @filp to the list of allowed open-files for this node. If @filp is
+ * already on this list, the ref-count is incremented.
+ *
+ * The list of allowed-users is preserved across drm_vma_offset_add() and
+ * drm_vma_offset_remove() calls. You may even call it if the node is currently
+ * not added to any offset-manager.
+ *
+ * You must remove all open-files the same number of times as you added them
+ * before destroying the node. Otherwise, you will leak memory.
+ *
+ * This is locked against concurrent access internally.
+ *
+ * RETURNS:
+ * 0 on success, negative error code on internal failure (out-of-mem)
+ */
+int drm_vma_node_allow(struct drm_vma_offset_node *node, struct file *filp)
+{
+	struct rb_node **iter;
+	struct rb_node *parent = NULL;
+	struct drm_vma_offset_file *new, *entry;
+	int ret = 0;
+
+	/* Preallocate entry to avoid atomic allocations below. It is quite
+	 * unlikely that an open-file is added twice to a single node so we
+	 * don't optimize for this case. OOM is checked below only if the entry
+	 * is actually used. */
+	new = kmalloc(sizeof(*entry), GFP_KERNEL);
+
+	write_lock(&node->vm_lock);
+
+	iter = &node->vm_files.rb_node;
+
+	while (likely(*iter)) {
+		parent = *iter;
+		entry = rb_entry(*iter, struct drm_vma_offset_file, vm_rb);
+
+		if (filp == entry->vm_filp) {
+			entry->vm_count++;
+			goto unlock;
+		} else if (filp > entry->vm_filp) {
+			iter = &(*iter)->rb_right;
+		} else {
+			iter = &(*iter)->rb_left;
+		}
+	}
+
+	if (!new) {
+		ret = -ENOMEM;
+		goto unlock;
+	}
+
+	new->vm_filp = filp;
+	new->vm_count = 1;
+	rb_link_node(&new->vm_rb, parent, iter);
+	rb_insert_color(&new->vm_rb, &node->vm_files);
+	new = NULL;
+
+unlock:
+	write_unlock(&node->vm_lock);
+	kfree(new);
+	return ret;
+}
+EXPORT_SYMBOL(drm_vma_node_allow);
+
+/**
+ * drm_vma_node_revoke - Remove open-file from list of allowed users
+ * @node: Node to modify
+ * @filp: Open file to remove
+ *
+ * Decrement the ref-count of @filp in the list of allowed open-files on @node.
+ * If the ref-count drops to zero, remove @filp from the list. You must call
+ * this once for every drm_vma_node_allow() on @filp.
+ *
+ * This is locked against concurrent access internally.
+ *
+ * If @filp is not on the list, nothing is done.
+ */
+void drm_vma_node_revoke(struct drm_vma_offset_node *node, struct file *filp)
+{
+	struct drm_vma_offset_file *entry;
+	struct rb_node *iter;
+
+	write_lock(&node->vm_lock);
+
+	iter = node->vm_files.rb_node;
+	while (likely(iter)) {
+		entry = rb_entry(iter, struct drm_vma_offset_file, vm_rb);
+		if (filp == entry->vm_filp) {
+			if (!--entry->vm_count) {
+				rb_erase(&entry->vm_rb, &node->vm_files);
+				kfree(entry);
+			}
+			break;
+		} else if (filp > entry->vm_filp) {
+			iter = iter->rb_right;
+		} else {
+			iter = iter->rb_left;
+		}
+	}
+
+	write_unlock(&node->vm_lock);
+}
+EXPORT_SYMBOL(drm_vma_node_revoke);
+
+/**
+ * drm_vma_node_is_allowed - Check whether an open-file is granted access
+ * @node: Node to check
+ * @filp: Open-file to check for
+ *
+ * Search the list in @node whether @filp is currently on the list of allowed
+ * open-files (see drm_vma_node_allow()).
+ *
+ * This is locked against concurrent access internally.
+ *
+ * RETURNS:
+ * true iff @filp is on the list
+ */
+bool drm_vma_node_is_allowed(struct drm_vma_offset_node *node,
+			     struct file *filp)
+{
+	struct drm_vma_offset_file *entry;
+	struct rb_node *iter;
+
+	read_lock(&node->vm_lock);
+
+	iter = node->vm_files.rb_node;
+	while (likely(iter)) {
+		entry = rb_entry(iter, struct drm_vma_offset_file, vm_rb);
+		if (filp == entry->vm_filp)
+			break;
+		else if (filp > entry->vm_filp)
+			iter = iter->rb_right;
+		else
+			iter = iter->rb_left;
+	}
+
+	read_unlock(&node->vm_lock);
+
+	return iter;
+}
+EXPORT_SYMBOL(drm_vma_node_is_allowed);