1#ifndef __DRM_VMA_MANAGER_H__
  2#define __DRM_VMA_MANAGER_H__
  3
  4/*
  5 * Copyright (c) 2013 David Herrmann <dh.herrmann@gmail.com>
  6 *
  7 * Permission is hereby granted, free of charge, to any person obtaining a
  8 * copy of this software and associated documentation files (the "Software"),
  9 * to deal in the Software without restriction, including without limitation
 10 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 11 * and/or sell copies of the Software, and to permit persons to whom the
 12 * Software is furnished to do so, subject to the following conditions:
 13 *
 14 * The above copyright notice and this permission notice shall be included in
 15 * all copies or substantial portions of the Software.
 16 *
 17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 20 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 21 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 22 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 23 * OTHER DEALINGS IN THE SOFTWARE.
 24 */
 25
 26#include <drm/drm_mm.h>
 27#include <linux/mm.h>
 28#include <linux/rbtree.h>
 29#include <linux/spinlock.h>
 30#include <linux/types.h>
 31
 32struct drm_file;
 33
 34struct drm_vma_offset_file {
 35	struct rb_node vm_rb;
 36	struct drm_file *vm_tag;
 37	unsigned long vm_count;
 38};
 39
 40struct drm_vma_offset_node {
 41	rwlock_t vm_lock;
 42	struct drm_mm_node vm_node;
 43	struct rb_root vm_files;
 44};
 45
 46struct drm_vma_offset_manager {
 47	rwlock_t vm_lock;
 48	struct drm_mm vm_addr_space_mm;
 49};
 50
 51void drm_vma_offset_manager_init(struct drm_vma_offset_manager *mgr,
 52				 unsigned long page_offset, unsigned long size);
 53void drm_vma_offset_manager_destroy(struct drm_vma_offset_manager *mgr);
 54
 55struct drm_vma_offset_node *drm_vma_offset_lookup_locked(struct drm_vma_offset_manager *mgr,
 56							   unsigned long start,
 57							   unsigned long pages);
 58int drm_vma_offset_add(struct drm_vma_offset_manager *mgr,
 59		       struct drm_vma_offset_node *node, unsigned long pages);
 60void drm_vma_offset_remove(struct drm_vma_offset_manager *mgr,
 61			   struct drm_vma_offset_node *node);
 62
 63int drm_vma_node_allow(struct drm_vma_offset_node *node, struct drm_file *tag);
 64void drm_vma_node_revoke(struct drm_vma_offset_node *node,
 65			 struct drm_file *tag);
 66bool drm_vma_node_is_allowed(struct drm_vma_offset_node *node,
 67			     struct drm_file *tag);
 68
 69/**
 70 * drm_vma_offset_exact_lookup_locked() - Look up node by exact address
 71 * @mgr: Manager object
 72 * @start: Start address (page-based, not byte-based)
 73 * @pages: Size of object (page-based)
 74 *
 75 * Same as drm_vma_offset_lookup_locked() but does not allow any offset into the node.
 76 * It only returns the exact object with the given start address.
 77 *
 78 * RETURNS:
 79 * Node at exact start address @start.
 80 */
 81static inline struct drm_vma_offset_node *
 82drm_vma_offset_exact_lookup_locked(struct drm_vma_offset_manager *mgr,
 83				   unsigned long start,
 84				   unsigned long pages)
 85{
 86	struct drm_vma_offset_node *node;
 87
 88	node = drm_vma_offset_lookup_locked(mgr, start, pages);
 89	return (node && node->vm_node.start == start) ? node : NULL;
 90}
 91
 92/**
 93 * drm_vma_offset_lock_lookup() - Lock lookup for extended private use
 94 * @mgr: Manager object
 95 *
 96 * Lock VMA manager for extended lookups. Only locked VMA function calls
 97 * are allowed while holding this lock. All other contexts are blocked from VMA
 98 * until the lock is released via drm_vma_offset_unlock_lookup().
 99 *
100 * Use this if you need to take a reference to the objects returned by
101 * drm_vma_offset_lookup_locked() before releasing this lock again.
102 *
103 * This lock must not be used for anything else than extended lookups. You must
104 * not call any other VMA helpers while holding this lock.
105 *
106 * Note: You're in atomic-context while holding this lock!
107 */
108static inline void drm_vma_offset_lock_lookup(struct drm_vma_offset_manager *mgr)
109{
110	read_lock(&mgr->vm_lock);
111}
112
113/**
114 * drm_vma_offset_unlock_lookup() - Unlock lookup for extended private use
115 * @mgr: Manager object
116 *
117 * Release lookup-lock. See drm_vma_offset_lock_lookup() for more information.
118 */
119static inline void drm_vma_offset_unlock_lookup(struct drm_vma_offset_manager *mgr)
120{
121	read_unlock(&mgr->vm_lock);
122}
123
124/**
125 * drm_vma_node_reset() - Initialize or reset node object
126 * @node: Node to initialize or reset
127 *
128 * Reset a node to its initial state. This must be called before using it with
129 * any VMA offset manager.
130 *
131 * This must not be called on an already allocated node, or you will leak
132 * memory.
133 */
134static inline void drm_vma_node_reset(struct drm_vma_offset_node *node)
135{
136	memset(node, 0, sizeof(*node));
137	node->vm_files = RB_ROOT;
138	rwlock_init(&node->vm_lock);
139}
140
141/**
142 * drm_vma_node_start() - Return start address for page-based addressing
143 * @node: Node to inspect
144 *
145 * Return the start address of the given node. This can be used as offset into
146 * the linear VM space that is provided by the VMA offset manager. Note that
147 * this can only be used for page-based addressing. If you need a proper offset
148 * for user-space mappings, you must apply "<< PAGE_SHIFT" or use the
149 * drm_vma_node_offset_addr() helper instead.
150 *
151 * RETURNS:
152 * Start address of @node for page-based addressing. 0 if the node does not
153 * have an offset allocated.
154 */
155static inline unsigned long drm_vma_node_start(const struct drm_vma_offset_node *node)
156{
157	return node->vm_node.start;
158}
159
160/**
161 * drm_vma_node_size() - Return size (page-based)
162 * @node: Node to inspect
163 *
164 * Return the size as number of pages for the given node. This is the same size
165 * that was passed to drm_vma_offset_add(). If no offset is allocated for the
166 * node, this is 0.
167 *
168 * RETURNS:
169 * Size of @node as number of pages. 0 if the node does not have an offset
170 * allocated.
171 */
172static inline unsigned long drm_vma_node_size(struct drm_vma_offset_node *node)
173{
174	return node->vm_node.size;
175}
176
177/**
178 * drm_vma_node_offset_addr() - Return sanitized offset for user-space mmaps
179 * @node: Linked offset node
180 *
181 * Same as drm_vma_node_start() but returns the address as a valid offset that
182 * can be used for user-space mappings during mmap().
183 * This must not be called on unlinked nodes.
184 *
185 * RETURNS:
186 * Offset of @node for byte-based addressing. 0 if the node does not have an
187 * object allocated.
188 */
189static inline __u64 drm_vma_node_offset_addr(struct drm_vma_offset_node *node)
190{
191	return ((__u64)node->vm_node.start) << PAGE_SHIFT;
192}
193
194/**
195 * drm_vma_node_unmap() - Unmap offset node
196 * @node: Offset node
197 * @file_mapping: Address space to unmap @node from
198 *
199 * Unmap all userspace mappings for a given offset node. The mappings must be
200 * associated with the @file_mapping address-space. If no offset exists
201 * nothing is done.
202 *
203 * This call is unlocked. The caller must guarantee that drm_vma_offset_remove()
204 * is not called on this node concurrently.
205 */
206static inline void drm_vma_node_unmap(struct drm_vma_offset_node *node,
207				      struct address_space *file_mapping)
208{
209	if (drm_mm_node_allocated(&node->vm_node))
210		unmap_mapping_range(file_mapping,
211				    drm_vma_node_offset_addr(node),
212				    drm_vma_node_size(node) << PAGE_SHIFT, 1);
213}
214
215/**
216 * drm_vma_node_verify_access() - Access verification helper for TTM
217 * @node: Offset node
218 * @tag: Tag of file to check
219 *
220 * This checks whether @tag is granted access to @node. It is the same as
221 * drm_vma_node_is_allowed() but suitable as drop-in helper for TTM
222 * verify_access() callbacks.
223 *
224 * RETURNS:
225 * 0 if access is granted, -EACCES otherwise.
226 */
227static inline int drm_vma_node_verify_access(struct drm_vma_offset_node *node,
228					     struct drm_file *tag)
229{
230	return drm_vma_node_is_allowed(node, tag) ? 0 : -EACCES;
231}
232
233#endif /* __DRM_VMA_MANAGER_H__ */