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
32 struct drm_file;
33
34 struct drm_vma_offset_file {
35 struct rb_node vm_rb;
36 struct drm_file *vm_tag;
37 unsigned long vm_count;
38 };
39
40 struct drm_vma_offset_node {
41 struct lock vm_lock;
42 struct drm_mm_node vm_node;
43 struct rb_node vm_rb;
44 struct rb_root vm_files;
45 };
46
47 struct drm_vma_offset_manager {
48 struct lock vm_lock;
49 struct rb_root vm_addr_space_rb;
50 struct drm_mm vm_addr_space_mm;
51 };
52
53 void drm_vma_offset_manager_init(struct drm_vma_offset_manager *mgr,
54 unsigned long page_offset, unsigned long size);
55 void drm_vma_offset_manager_destroy(struct drm_vma_offset_manager *mgr);
56
57 struct drm_vma_offset_node *drm_vma_offset_lookup_locked(struct drm_vma_offset_manager *mgr,
58 unsigned long start,
59 unsigned long pages);
60 int drm_vma_offset_add(struct drm_vma_offset_manager *mgr,
61 struct drm_vma_offset_node *node, unsigned long pages);
62 void drm_vma_offset_remove(struct drm_vma_offset_manager *mgr,
63 struct drm_vma_offset_node *node);
64
65 int drm_vma_node_allow(struct drm_vma_offset_node *node, struct drm_file *tag);
66 void drm_vma_node_revoke(struct drm_vma_offset_node *node,
67 struct drm_file *tag);
68 bool drm_vma_node_is_allowed(struct drm_vma_offset_node *node,
69 struct drm_file *tag);
70
71 /**
72 * drm_vma_offset_exact_lookup_locked() - Look up node by exact address
73 * @mgr: Manager object
74 * @start: Start address (page-based, not byte-based)
75 * @pages: Size of object (page-based)
76 *
77 * Same as drm_vma_offset_lookup_locked() but does not allow any offset into the node.
78 * It only returns the exact object with the given start address.
79 *
80 * RETURNS:
81 * Node at exact start address @start.
82 */
83 static inline struct drm_vma_offset_node *
drm_vma_offset_exact_lookup_locked(struct drm_vma_offset_manager * mgr,unsigned long start,unsigned long pages)84 drm_vma_offset_exact_lookup_locked(struct drm_vma_offset_manager *mgr,
85 unsigned long start,
86 unsigned long pages)
87 {
88 struct drm_vma_offset_node *node;
89
90 node = drm_vma_offset_lookup_locked(mgr, start, pages);
91 return (node && node->vm_node.start == start) ? node : NULL;
92 }
93
94 /**
95 * drm_vma_offset_lock_lookup() - Lock lookup for extended private use
96 * @mgr: Manager object
97 *
98 * Lock VMA manager for extended lookups. Only locked VMA function calls
99 * are allowed while holding this lock. All other contexts are blocked from VMA
100 * until the lock is released via drm_vma_offset_unlock_lookup().
101 *
102 * Use this if you need to take a reference to the objects returned by
103 * drm_vma_offset_lookup_locked() before releasing this lock again.
104 *
105 * This lock must not be used for anything else than extended lookups. You must
106 * not call any other VMA helpers while holding this lock.
107 *
108 * Note: You're in atomic-context while holding this lock!
109 */
drm_vma_offset_lock_lookup(struct drm_vma_offset_manager * mgr)110 static inline void drm_vma_offset_lock_lookup(struct drm_vma_offset_manager *mgr)
111 {
112 lockmgr(&mgr->vm_lock, LK_EXCLUSIVE);
113 }
114
115 /**
116 * drm_vma_offset_unlock_lookup() - Unlock lookup for extended private use
117 * @mgr: Manager object
118 *
119 * Release lookup-lock. See drm_vma_offset_lock_lookup() for more information.
120 */
drm_vma_offset_unlock_lookup(struct drm_vma_offset_manager * mgr)121 static inline void drm_vma_offset_unlock_lookup(struct drm_vma_offset_manager *mgr)
122 {
123 lockmgr(&mgr->vm_lock, LK_RELEASE);
124 }
125
126 /**
127 * drm_vma_node_reset() - Initialize or reset node object
128 * @node: Node to initialize or reset
129 *
130 * Reset a node to its initial state. This must be called before using it with
131 * any VMA offset manager.
132 *
133 * This must not be called on an already allocated node, or you will leak
134 * memory.
135 */
drm_vma_node_reset(struct drm_vma_offset_node * node)136 static inline void drm_vma_node_reset(struct drm_vma_offset_node *node)
137 {
138 memset(node, 0, sizeof(*node));
139 node->vm_files = LINUX_RB_ROOT;
140 lockinit(&node->vm_lock, "vmlock", 0, LK_CANRECURSE);
141 }
142
143 /**
144 * drm_vma_node_start() - Return start address for page-based addressing
145 * @node: Node to inspect
146 *
147 * Return the start address of the given node. This can be used as offset into
148 * the linear VM space that is provided by the VMA offset manager. Note that
149 * this can only be used for page-based addressing. If you need a proper offset
150 * for user-space mappings, you must apply "<< PAGE_SHIFT" or use the
151 * drm_vma_node_offset_addr() helper instead.
152 *
153 * RETURNS:
154 * Start address of @node for page-based addressing. 0 if the node does not
155 * have an offset allocated.
156 */
drm_vma_node_start(struct drm_vma_offset_node * node)157 static inline unsigned long drm_vma_node_start(struct drm_vma_offset_node *node)
158 {
159 return node->vm_node.start;
160 }
161
162 /**
163 * drm_vma_node_size() - Return size (page-based)
164 * @node: Node to inspect
165 *
166 * Return the size as number of pages for the given node. This is the same size
167 * that was passed to drm_vma_offset_add(). If no offset is allocated for the
168 * node, this is 0.
169 *
170 * RETURNS:
171 * Size of @node as number of pages. 0 if the node does not have an offset
172 * allocated.
173 */
drm_vma_node_size(struct drm_vma_offset_node * node)174 static inline unsigned long drm_vma_node_size(struct drm_vma_offset_node *node)
175 {
176 return node->vm_node.size;
177 }
178
179 /**
180 * drm_vma_node_has_offset() - Check whether node is added to offset manager
181 * @node: Node to be checked
182 *
183 * RETURNS:
184 * true iff the node was previously allocated an offset and added to
185 * an vma offset manager.
186 */
drm_vma_node_has_offset(struct drm_vma_offset_node * node)187 static inline bool drm_vma_node_has_offset(struct drm_vma_offset_node *node)
188 {
189 return drm_mm_node_allocated(&node->vm_node);
190 }
191
192 /**
193 * drm_vma_node_offset_addr() - Return sanitized offset for user-space mmaps
194 * @node: Linked offset node
195 *
196 * Same as drm_vma_node_start() but returns the address as a valid offset that
197 * can be used for user-space mappings during mmap().
198 * This must not be called on unlinked nodes.
199 *
200 * RETURNS:
201 * Offset of @node for byte-based addressing. 0 if the node does not have an
202 * object allocated.
203 */
drm_vma_node_offset_addr(struct drm_vma_offset_node * node)204 static inline __u64 drm_vma_node_offset_addr(struct drm_vma_offset_node *node)
205 {
206 return ((__u64)node->vm_node.start) << PAGE_SHIFT;
207 }
208
209 #if 0
210 /**
211 * drm_vma_node_unmap() - Unmap offset node
212 * @node: Offset node
213 * @file_mapping: Address space to unmap @node from
214 *
215 * Unmap all userspace mappings for a given offset node. The mappings must be
216 * associated with the @file_mapping address-space. If no offset exists
217 * nothing is done.
218 *
219 * This call is unlocked. The caller must guarantee that drm_vma_offset_remove()
220 * is not called on this node concurrently.
221 */
222 static inline void drm_vma_node_unmap(struct drm_vma_offset_node *node,
223 struct address_space *file_mapping)
224 {
225 if (file_mapping && drm_vma_node_has_offset(node))
226 unmap_mapping_range(file_mapping,
227 drm_vma_node_offset_addr(node),
228 drm_vma_node_size(node) << PAGE_SHIFT, 1);
229 }
230 #endif
231
232 /**
233 * drm_vma_node_verify_access() - Access verification helper for TTM
234 * @node: Offset node
235 * @tag: Tag of file to check
236 *
237 * This checks whether @tag is granted access to @node. It is the same as
238 * drm_vma_node_is_allowed() but suitable as drop-in helper for TTM
239 * verify_access() callbacks.
240 *
241 * RETURNS:
242 * 0 if access is granted, -EACCES otherwise.
243 */
drm_vma_node_verify_access(struct drm_vma_offset_node * node,struct drm_file * tag)244 static inline int drm_vma_node_verify_access(struct drm_vma_offset_node *node,
245 struct drm_file *tag)
246 {
247 return drm_vma_node_is_allowed(node, tag) ? 0 : -EACCES;
248 }
249
250 #endif /* __DRM_VMA_MANAGER_H__ */
251