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