Line data Source code
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 : /* We make up offsets for buffer objects so we can recognize them at
33 : * mmap time. pgoff in mmap is an unsigned long, so we need to make sure
34 : * that the faked up offset will fit
35 : */
36 : #if BITS_PER_LONG == 64
37 : #define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFFUL >> PAGE_SHIFT) + 1)
38 : #define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFFUL >> PAGE_SHIFT) * 256)
39 : #else
40 : #define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFUL >> PAGE_SHIFT) + 1)
41 : #define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFUL >> PAGE_SHIFT) * 16)
42 : #endif
43 :
44 : struct drm_file;
45 :
46 : struct drm_vma_offset_file {
47 : struct rb_node vm_rb;
48 : struct drm_file *vm_tag;
49 : unsigned long vm_count;
50 : };
51 :
52 : struct drm_vma_offset_node {
53 : rwlock_t vm_lock;
54 : struct drm_mm_node vm_node;
55 : struct rb_root vm_files;
56 : void *driver_private;
57 : };
58 :
59 : struct drm_vma_offset_manager {
60 : rwlock_t vm_lock;
61 : struct drm_mm vm_addr_space_mm;
62 : };
63 :
64 : void drm_vma_offset_manager_init(struct drm_vma_offset_manager *mgr,
65 : unsigned long page_offset, unsigned long size);
66 : void drm_vma_offset_manager_destroy(struct drm_vma_offset_manager *mgr);
67 :
68 : struct drm_vma_offset_node *drm_vma_offset_lookup_locked(struct drm_vma_offset_manager *mgr,
69 : unsigned long start,
70 : unsigned long pages);
71 : int drm_vma_offset_add(struct drm_vma_offset_manager *mgr,
72 : struct drm_vma_offset_node *node, unsigned long pages);
73 : void drm_vma_offset_remove(struct drm_vma_offset_manager *mgr,
74 : struct drm_vma_offset_node *node);
75 :
76 : int drm_vma_node_allow(struct drm_vma_offset_node *node, struct drm_file *tag);
77 : void drm_vma_node_revoke(struct drm_vma_offset_node *node,
78 : struct drm_file *tag);
79 : bool drm_vma_node_is_allowed(struct drm_vma_offset_node *node,
80 : struct drm_file *tag);
81 :
82 : /**
83 : * drm_vma_offset_exact_lookup_locked() - Look up node by exact address
84 : * @mgr: Manager object
85 : * @start: Start address (page-based, not byte-based)
86 : * @pages: Size of object (page-based)
87 : *
88 : * Same as drm_vma_offset_lookup_locked() but does not allow any offset into the node.
89 : * It only returns the exact object with the given start address.
90 : *
91 : * RETURNS:
92 : * Node at exact start address @start.
93 : */
94 : static inline struct drm_vma_offset_node *
95 : drm_vma_offset_exact_lookup_locked(struct drm_vma_offset_manager *mgr,
96 : unsigned long start,
97 : unsigned long pages)
98 : {
99 : struct drm_vma_offset_node *node;
100 :
101 0 : node = drm_vma_offset_lookup_locked(mgr, start, pages);
102 0 : return (node && node->vm_node.start == start) ? node : NULL;
103 : }
104 :
105 : /**
106 : * drm_vma_offset_lock_lookup() - Lock lookup for extended private use
107 : * @mgr: Manager object
108 : *
109 : * Lock VMA manager for extended lookups. Only locked VMA function calls
110 : * are allowed while holding this lock. All other contexts are blocked from VMA
111 : * until the lock is released via drm_vma_offset_unlock_lookup().
112 : *
113 : * Use this if you need to take a reference to the objects returned by
114 : * drm_vma_offset_lookup_locked() before releasing this lock again.
115 : *
116 : * This lock must not be used for anything else than extended lookups. You must
117 : * not call any other VMA helpers while holding this lock.
118 : *
119 : * Note: You're in atomic-context while holding this lock!
120 : */
121 : static inline void drm_vma_offset_lock_lookup(struct drm_vma_offset_manager *mgr)
122 : {
123 0 : read_lock(&mgr->vm_lock);
124 : }
125 :
126 : /**
127 : * drm_vma_offset_unlock_lookup() - Unlock lookup for extended private use
128 : * @mgr: Manager object
129 : *
130 : * Release lookup-lock. See drm_vma_offset_lock_lookup() for more information.
131 : */
132 : static inline void drm_vma_offset_unlock_lookup(struct drm_vma_offset_manager *mgr)
133 : {
134 0 : read_unlock(&mgr->vm_lock);
135 : }
136 :
137 : /**
138 : * drm_vma_node_reset() - Initialize or reset node object
139 : * @node: Node to initialize or reset
140 : *
141 : * Reset a node to its initial state. This must be called before using it with
142 : * any VMA offset manager.
143 : *
144 : * This must not be called on an already allocated node, or you will leak
145 : * memory.
146 : */
147 : static inline void drm_vma_node_reset(struct drm_vma_offset_node *node)
148 : {
149 0 : memset(node, 0, sizeof(*node));
150 0 : node->vm_files = RB_ROOT;
151 : rwlock_init(&node->vm_lock);
152 : }
153 :
154 : /**
155 : * drm_vma_node_start() - Return start address for page-based addressing
156 : * @node: Node to inspect
157 : *
158 : * Return the start address of the given node. This can be used as offset into
159 : * the linear VM space that is provided by the VMA offset manager. Note that
160 : * this can only be used for page-based addressing. If you need a proper offset
161 : * for user-space mappings, you must apply "<< PAGE_SHIFT" or use the
162 : * drm_vma_node_offset_addr() helper instead.
163 : *
164 : * RETURNS:
165 : * Start address of @node for page-based addressing. 0 if the node does not
166 : * have an offset allocated.
167 : */
168 : static inline unsigned long drm_vma_node_start(const struct drm_vma_offset_node *node)
169 : {
170 : return node->vm_node.start;
171 : }
172 :
173 : /**
174 : * drm_vma_node_size() - Return size (page-based)
175 : * @node: Node to inspect
176 : *
177 : * Return the size as number of pages for the given node. This is the same size
178 : * that was passed to drm_vma_offset_add(). If no offset is allocated for the
179 : * node, this is 0.
180 : *
181 : * RETURNS:
182 : * Size of @node as number of pages. 0 if the node does not have an offset
183 : * allocated.
184 : */
185 : static inline unsigned long drm_vma_node_size(struct drm_vma_offset_node *node)
186 : {
187 : return node->vm_node.size;
188 : }
189 :
190 : /**
191 : * drm_vma_node_offset_addr() - Return sanitized offset for user-space mmaps
192 : * @node: Linked offset node
193 : *
194 : * Same as drm_vma_node_start() but returns the address as a valid offset that
195 : * can be used for user-space mappings during mmap().
196 : * This must not be called on unlinked nodes.
197 : *
198 : * RETURNS:
199 : * Offset of @node for byte-based addressing. 0 if the node does not have an
200 : * object allocated.
201 : */
202 : static inline __u64 drm_vma_node_offset_addr(struct drm_vma_offset_node *node)
203 : {
204 0 : return ((__u64)node->vm_node.start) << PAGE_SHIFT;
205 : }
206 :
207 : /**
208 : * drm_vma_node_unmap() - Unmap offset node
209 : * @node: Offset node
210 : * @file_mapping: Address space to unmap @node from
211 : *
212 : * Unmap all userspace mappings for a given offset node. The mappings must be
213 : * associated with the @file_mapping address-space. If no offset exists
214 : * nothing is done.
215 : *
216 : * This call is unlocked. The caller must guarantee that drm_vma_offset_remove()
217 : * is not called on this node concurrently.
218 : */
219 0 : static inline void drm_vma_node_unmap(struct drm_vma_offset_node *node,
220 : struct address_space *file_mapping)
221 : {
222 0 : if (drm_mm_node_allocated(&node->vm_node))
223 0 : unmap_mapping_range(file_mapping,
224 0 : drm_vma_node_offset_addr(node),
225 0 : drm_vma_node_size(node) << PAGE_SHIFT, 1);
226 0 : }
227 :
228 : /**
229 : * drm_vma_node_verify_access() - Access verification helper for TTM
230 : * @node: Offset node
231 : * @tag: Tag of file to check
232 : *
233 : * This checks whether @tag is granted access to @node. It is the same as
234 : * drm_vma_node_is_allowed() but suitable as drop-in helper for TTM
235 : * verify_access() callbacks.
236 : *
237 : * RETURNS:
238 : * 0 if access is granted, -EACCES otherwise.
239 : */
240 : static inline int drm_vma_node_verify_access(struct drm_vma_offset_node *node,
241 : struct drm_file *tag)
242 : {
243 : return drm_vma_node_is_allowed(node, tag) ? 0 : -EACCES;
244 : }
245 :
246 : #endif /* __DRM_VMA_MANAGER_H__ */
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