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
44struct drm_file;
45
46struct drm_vma_offset_file {
47 struct rb_node vm_rb;
48 struct drm_file *vm_tag;
49 unsigned long vm_count;
50};
51
52struct 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
59struct drm_vma_offset_manager {
60 rwlock_t vm_lock;
61 struct drm_mm vm_addr_space_mm;
62};
63
64void drm_vma_offset_manager_init(struct drm_vma_offset_manager *mgr,
65 unsigned long page_offset, unsigned long size);
66void drm_vma_offset_manager_destroy(struct drm_vma_offset_manager *mgr);
67
68struct drm_vma_offset_node *drm_vma_offset_lookup_locked(struct drm_vma_offset_manager *mgr,
69 unsigned long start,
70 unsigned long pages);
71int drm_vma_offset_add(struct drm_vma_offset_manager *mgr,
72 struct drm_vma_offset_node *node, unsigned long pages);
73void drm_vma_offset_remove(struct drm_vma_offset_manager *mgr,
74 struct drm_vma_offset_node *node);
75
76int drm_vma_node_allow(struct drm_vma_offset_node *node, struct drm_file *tag);
77int drm_vma_node_allow_once(struct drm_vma_offset_node *node, struct drm_file *tag);
78void drm_vma_node_revoke(struct drm_vma_offset_node *node,
79 struct drm_file *tag);
80bool 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 */
95static inline struct drm_vma_offset_node *
96drm_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 node = drm_vma_offset_lookup_locked(mgr, start, pages);
103 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 */
122static inline void drm_vma_offset_lock_lookup(struct drm_vma_offset_manager *mgr)
123{
124 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 */
133static inline void drm_vma_offset_unlock_lookup(struct drm_vma_offset_manager *mgr)
134{
135 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 */
148static inline void drm_vma_node_reset(struct drm_vma_offset_node *node)
149{
150 memset(s: node, c: 0, n: sizeof(*node));
151 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 */
169static 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 */
186static 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 */
203static inline __u64 drm_vma_node_offset_addr(struct drm_vma_offset_node *node)
204{
205 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 */
220static 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: &node->vm_node))
224 unmap_mapping_range(mapping: file_mapping,
225 holebegin: drm_vma_node_offset_addr(node),
226 holelen: drm_vma_node_size(node) << PAGE_SHIFT, even_cows: 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 */
241static 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__ */
248