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