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fe3078fa DH |
1 | /* |
2 | * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA | |
3 | * Copyright (c) 2012 David Airlie <airlied@linux.ie> | |
4 | * Copyright (c) 2013 David Herrmann <dh.herrmann@gmail.com> | |
5 | * | |
6 | * Permission is hereby granted, free of charge, to any person obtaining a | |
7 | * copy of this software and associated documentation files (the "Software"), | |
8 | * to deal in the Software without restriction, including without limitation | |
9 | * the rights to use, copy, modify, merge, publish, distribute, sublicense, | |
10 | * and/or sell copies of the Software, and to permit persons to whom the | |
11 | * Software is furnished to do so, subject to the following conditions: | |
12 | * | |
13 | * The above copyright notice and this permission notice shall be included in | |
14 | * all copies or substantial portions of the Software. | |
15 | * | |
16 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
17 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
18 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL | |
19 | * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR | |
20 | * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, | |
21 | * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR | |
22 | * OTHER DEALINGS IN THE SOFTWARE. | |
23 | */ | |
24 | ||
25 | #include <drm/drmP.h> | |
26 | #include <drm/drm_mm.h> | |
27 | #include <drm/drm_vma_manager.h> | |
28 | #include <linux/mm.h> | |
29 | #include <linux/module.h> | |
30 | #include <linux/rbtree.h> | |
31 | #include <linux/slab.h> | |
32 | #include <linux/spinlock.h> | |
33 | #include <linux/types.h> | |
34 | ||
35 | /** | |
36 | * DOC: vma offset manager | |
37 | * | |
38 | * The vma-manager is responsible to map arbitrary driver-dependent memory | |
39 | * regions into the linear user address-space. It provides offsets to the | |
40 | * caller which can then be used on the address_space of the drm-device. It | |
41 | * takes care to not overlap regions, size them appropriately and to not | |
42 | * confuse mm-core by inconsistent fake vm_pgoff fields. | |
43 | * Drivers shouldn't use this for object placement in VMEM. This manager should | |
44 | * only be used to manage mappings into linear user-space VMs. | |
45 | * | |
46 | * We use drm_mm as backend to manage object allocations. But it is highly | |
47 | * optimized for alloc/free calls, not lookups. Hence, we use an rb-tree to | |
48 | * speed up offset lookups. | |
49 | * | |
50 | * You must not use multiple offset managers on a single address_space. | |
51 | * Otherwise, mm-core will be unable to tear down memory mappings as the VM will | |
0661a336 | 52 | * no longer be linear. |
fe3078fa DH |
53 | * |
54 | * This offset manager works on page-based addresses. That is, every argument | |
55 | * and return code (with the exception of drm_vma_node_offset_addr()) is given | |
56 | * in number of pages, not number of bytes. That means, object sizes and offsets | |
57 | * must always be page-aligned (as usual). | |
58 | * If you want to get a valid byte-based user-space address for a given offset, | |
59 | * please see drm_vma_node_offset_addr(). | |
88d7ebe5 DH |
60 | * |
61 | * Additionally to offset management, the vma offset manager also handles access | |
62 | * management. For every open-file context that is allowed to access a given | |
63 | * node, you must call drm_vma_node_allow(). Otherwise, an mmap() call on this | |
64 | * open-file with the offset of the node will fail with -EACCES. To revoke | |
65 | * access again, use drm_vma_node_revoke(). However, the caller is responsible | |
66 | * for destroying already existing mappings, if required. | |
fe3078fa DH |
67 | */ |
68 | ||
69 | /** | |
70 | * drm_vma_offset_manager_init - Initialize new offset-manager | |
71 | * @mgr: Manager object | |
72 | * @page_offset: Offset of available memory area (page-based) | |
73 | * @size: Size of available address space range (page-based) | |
74 | * | |
75 | * Initialize a new offset-manager. The offset and area size available for the | |
76 | * manager are given as @page_offset and @size. Both are interpreted as | |
77 | * page-numbers, not bytes. | |
78 | * | |
79 | * Adding/removing nodes from the manager is locked internally and protected | |
80 | * against concurrent access. However, node allocation and destruction is left | |
81 | * for the caller. While calling into the vma-manager, a given node must | |
82 | * always be guaranteed to be referenced. | |
83 | */ | |
84 | void drm_vma_offset_manager_init(struct drm_vma_offset_manager *mgr, | |
85 | unsigned long page_offset, unsigned long size) | |
86 | { | |
87 | rwlock_init(&mgr->vm_lock); | |
fe3078fa DH |
88 | drm_mm_init(&mgr->vm_addr_space_mm, page_offset, size); |
89 | } | |
90 | EXPORT_SYMBOL(drm_vma_offset_manager_init); | |
91 | ||
92 | /** | |
93 | * drm_vma_offset_manager_destroy() - Destroy offset manager | |
94 | * @mgr: Manager object | |
95 | * | |
96 | * Destroy an object manager which was previously created via | |
97 | * drm_vma_offset_manager_init(). The caller must remove all allocated nodes | |
98 | * before destroying the manager. Otherwise, drm_mm will refuse to free the | |
99 | * requested resources. | |
100 | * | |
101 | * The manager must not be accessed after this function is called. | |
102 | */ | |
103 | void drm_vma_offset_manager_destroy(struct drm_vma_offset_manager *mgr) | |
104 | { | |
105 | /* take the lock to protect against buggy drivers */ | |
106 | write_lock(&mgr->vm_lock); | |
107 | drm_mm_takedown(&mgr->vm_addr_space_mm); | |
108 | write_unlock(&mgr->vm_lock); | |
109 | } | |
110 | EXPORT_SYMBOL(drm_vma_offset_manager_destroy); | |
111 | ||
112 | /** | |
2225cfe4 | 113 | * drm_vma_offset_lookup_locked() - Find node in offset space |
fe3078fa DH |
114 | * @mgr: Manager object |
115 | * @start: Start address for object (page-based) | |
116 | * @pages: Size of object (page-based) | |
117 | * | |
118 | * Find a node given a start address and object size. This returns the _best_ | |
119 | * match for the given node. That is, @start may point somewhere into a valid | |
120 | * region and the given node will be returned, as long as the node spans the | |
121 | * whole requested area (given the size in number of pages as @pages). | |
122 | * | |
2225cfe4 DV |
123 | * Note that before lookup the vma offset manager lookup lock must be acquired |
124 | * with drm_vma_offset_lock_lookup(). See there for an example. This can then be | |
125 | * used to implement weakly referenced lookups using kref_get_unless_zero(). | |
fe3078fa | 126 | * |
2225cfe4 | 127 | * Example: |
da5335b8 DV |
128 | * |
129 | * :: | |
130 | * | |
2225cfe4 DV |
131 | * drm_vma_offset_lock_lookup(mgr); |
132 | * node = drm_vma_offset_lookup_locked(mgr); | |
133 | * if (node) | |
134 | * kref_get_unless_zero(container_of(node, sth, entr)); | |
135 | * drm_vma_offset_unlock_lookup(mgr); | |
fe3078fa DH |
136 | * |
137 | * RETURNS: | |
138 | * Returns NULL if no suitable node can be found. Otherwise, the best match | |
2225cfe4 DV |
139 | * is returned. It's the caller's responsibility to make sure the node doesn't |
140 | * get destroyed before the caller can access it. | |
fe3078fa DH |
141 | */ |
142 | struct drm_vma_offset_node *drm_vma_offset_lookup_locked(struct drm_vma_offset_manager *mgr, | |
143 | unsigned long start, | |
144 | unsigned long pages) | |
145 | { | |
db2395ec | 146 | struct drm_mm_node *node, *best; |
fe3078fa DH |
147 | struct rb_node *iter; |
148 | unsigned long offset; | |
149 | ||
f808c13f | 150 | iter = mgr->vm_addr_space_mm.interval_tree.rb_root.rb_node; |
fe3078fa DH |
151 | best = NULL; |
152 | ||
153 | while (likely(iter)) { | |
db2395ec CW |
154 | node = rb_entry(iter, struct drm_mm_node, rb); |
155 | offset = node->start; | |
fe3078fa DH |
156 | if (start >= offset) { |
157 | iter = iter->rb_right; | |
158 | best = node; | |
159 | if (start == offset) | |
160 | break; | |
161 | } else { | |
162 | iter = iter->rb_left; | |
163 | } | |
164 | } | |
165 | ||
166 | /* verify that the node spans the requested area */ | |
167 | if (best) { | |
db2395ec | 168 | offset = best->start + best->size; |
fe3078fa DH |
169 | if (offset < start + pages) |
170 | best = NULL; | |
171 | } | |
172 | ||
db2395ec CW |
173 | if (!best) |
174 | return NULL; | |
fe3078fa | 175 | |
db2395ec | 176 | return container_of(best, struct drm_vma_offset_node, vm_node); |
fe3078fa | 177 | } |
db2395ec | 178 | EXPORT_SYMBOL(drm_vma_offset_lookup_locked); |
fe3078fa DH |
179 | |
180 | /** | |
181 | * drm_vma_offset_add() - Add offset node to manager | |
182 | * @mgr: Manager object | |
183 | * @node: Node to be added | |
184 | * @pages: Allocation size visible to user-space (in number of pages) | |
185 | * | |
186 | * Add a node to the offset-manager. If the node was already added, this does | |
187 | * nothing and return 0. @pages is the size of the object given in number of | |
188 | * pages. | |
189 | * After this call succeeds, you can access the offset of the node until it | |
190 | * is removed again. | |
191 | * | |
192 | * If this call fails, it is safe to retry the operation or call | |
193 | * drm_vma_offset_remove(), anyway. However, no cleanup is required in that | |
194 | * case. | |
195 | * | |
196 | * @pages is not required to be the same size as the underlying memory object | |
197 | * that you want to map. It only limits the size that user-space can map into | |
198 | * their address space. | |
199 | * | |
200 | * RETURNS: | |
201 | * 0 on success, negative error code on failure. | |
202 | */ | |
203 | int drm_vma_offset_add(struct drm_vma_offset_manager *mgr, | |
204 | struct drm_vma_offset_node *node, unsigned long pages) | |
205 | { | |
206 | int ret; | |
207 | ||
208 | write_lock(&mgr->vm_lock); | |
209 | ||
210 | if (drm_mm_node_allocated(&node->vm_node)) { | |
211 | ret = 0; | |
212 | goto out_unlock; | |
213 | } | |
214 | ||
4e64e553 | 215 | ret = drm_mm_insert_node(&mgr->vm_addr_space_mm, &node->vm_node, pages); |
fe3078fa DH |
216 | if (ret) |
217 | goto out_unlock; | |
218 | ||
fe3078fa DH |
219 | out_unlock: |
220 | write_unlock(&mgr->vm_lock); | |
221 | return ret; | |
222 | } | |
223 | EXPORT_SYMBOL(drm_vma_offset_add); | |
224 | ||
225 | /** | |
226 | * drm_vma_offset_remove() - Remove offset node from manager | |
227 | * @mgr: Manager object | |
228 | * @node: Node to be removed | |
229 | * | |
230 | * Remove a node from the offset manager. If the node wasn't added before, this | |
231 | * does nothing. After this call returns, the offset and size will be 0 until a | |
232 | * new offset is allocated via drm_vma_offset_add() again. Helper functions like | |
233 | * drm_vma_node_start() and drm_vma_node_offset_addr() will return 0 if no | |
234 | * offset is allocated. | |
235 | */ | |
236 | void drm_vma_offset_remove(struct drm_vma_offset_manager *mgr, | |
237 | struct drm_vma_offset_node *node) | |
238 | { | |
239 | write_lock(&mgr->vm_lock); | |
240 | ||
241 | if (drm_mm_node_allocated(&node->vm_node)) { | |
fe3078fa DH |
242 | drm_mm_remove_node(&node->vm_node); |
243 | memset(&node->vm_node, 0, sizeof(node->vm_node)); | |
244 | } | |
245 | ||
246 | write_unlock(&mgr->vm_lock); | |
247 | } | |
248 | EXPORT_SYMBOL(drm_vma_offset_remove); | |
88d7ebe5 DH |
249 | |
250 | /** | |
251 | * drm_vma_node_allow - Add open-file to list of allowed users | |
252 | * @node: Node to modify | |
d9a1f0b4 | 253 | * @tag: Tag of file to remove |
88d7ebe5 | 254 | * |
d9a1f0b4 | 255 | * Add @tag to the list of allowed open-files for this node. If @tag is |
88d7ebe5 DH |
256 | * already on this list, the ref-count is incremented. |
257 | * | |
258 | * The list of allowed-users is preserved across drm_vma_offset_add() and | |
259 | * drm_vma_offset_remove() calls. You may even call it if the node is currently | |
260 | * not added to any offset-manager. | |
261 | * | |
262 | * You must remove all open-files the same number of times as you added them | |
263 | * before destroying the node. Otherwise, you will leak memory. | |
264 | * | |
265 | * This is locked against concurrent access internally. | |
266 | * | |
267 | * RETURNS: | |
268 | * 0 on success, negative error code on internal failure (out-of-mem) | |
269 | */ | |
d9a1f0b4 | 270 | int drm_vma_node_allow(struct drm_vma_offset_node *node, struct drm_file *tag) |
88d7ebe5 DH |
271 | { |
272 | struct rb_node **iter; | |
273 | struct rb_node *parent = NULL; | |
274 | struct drm_vma_offset_file *new, *entry; | |
275 | int ret = 0; | |
276 | ||
277 | /* Preallocate entry to avoid atomic allocations below. It is quite | |
278 | * unlikely that an open-file is added twice to a single node so we | |
279 | * don't optimize for this case. OOM is checked below only if the entry | |
280 | * is actually used. */ | |
281 | new = kmalloc(sizeof(*entry), GFP_KERNEL); | |
282 | ||
283 | write_lock(&node->vm_lock); | |
284 | ||
285 | iter = &node->vm_files.rb_node; | |
286 | ||
287 | while (likely(*iter)) { | |
288 | parent = *iter; | |
289 | entry = rb_entry(*iter, struct drm_vma_offset_file, vm_rb); | |
290 | ||
d9a1f0b4 | 291 | if (tag == entry->vm_tag) { |
88d7ebe5 DH |
292 | entry->vm_count++; |
293 | goto unlock; | |
d9a1f0b4 | 294 | } else if (tag > entry->vm_tag) { |
88d7ebe5 DH |
295 | iter = &(*iter)->rb_right; |
296 | } else { | |
297 | iter = &(*iter)->rb_left; | |
298 | } | |
299 | } | |
300 | ||
301 | if (!new) { | |
302 | ret = -ENOMEM; | |
303 | goto unlock; | |
304 | } | |
305 | ||
d9a1f0b4 | 306 | new->vm_tag = tag; |
88d7ebe5 DH |
307 | new->vm_count = 1; |
308 | rb_link_node(&new->vm_rb, parent, iter); | |
309 | rb_insert_color(&new->vm_rb, &node->vm_files); | |
310 | new = NULL; | |
311 | ||
312 | unlock: | |
313 | write_unlock(&node->vm_lock); | |
314 | kfree(new); | |
315 | return ret; | |
316 | } | |
317 | EXPORT_SYMBOL(drm_vma_node_allow); | |
318 | ||
319 | /** | |
320 | * drm_vma_node_revoke - Remove open-file from list of allowed users | |
321 | * @node: Node to modify | |
d9a1f0b4 | 322 | * @tag: Tag of file to remove |
88d7ebe5 | 323 | * |
d9a1f0b4 DH |
324 | * Decrement the ref-count of @tag in the list of allowed open-files on @node. |
325 | * If the ref-count drops to zero, remove @tag from the list. You must call | |
326 | * this once for every drm_vma_node_allow() on @tag. | |
88d7ebe5 DH |
327 | * |
328 | * This is locked against concurrent access internally. | |
329 | * | |
d9a1f0b4 | 330 | * If @tag is not on the list, nothing is done. |
88d7ebe5 | 331 | */ |
d9a1f0b4 DH |
332 | void drm_vma_node_revoke(struct drm_vma_offset_node *node, |
333 | struct drm_file *tag) | |
88d7ebe5 DH |
334 | { |
335 | struct drm_vma_offset_file *entry; | |
336 | struct rb_node *iter; | |
337 | ||
338 | write_lock(&node->vm_lock); | |
339 | ||
340 | iter = node->vm_files.rb_node; | |
341 | while (likely(iter)) { | |
342 | entry = rb_entry(iter, struct drm_vma_offset_file, vm_rb); | |
d9a1f0b4 | 343 | if (tag == entry->vm_tag) { |
88d7ebe5 DH |
344 | if (!--entry->vm_count) { |
345 | rb_erase(&entry->vm_rb, &node->vm_files); | |
346 | kfree(entry); | |
347 | } | |
348 | break; | |
d9a1f0b4 | 349 | } else if (tag > entry->vm_tag) { |
88d7ebe5 DH |
350 | iter = iter->rb_right; |
351 | } else { | |
352 | iter = iter->rb_left; | |
353 | } | |
354 | } | |
355 | ||
356 | write_unlock(&node->vm_lock); | |
357 | } | |
358 | EXPORT_SYMBOL(drm_vma_node_revoke); | |
359 | ||
360 | /** | |
361 | * drm_vma_node_is_allowed - Check whether an open-file is granted access | |
362 | * @node: Node to check | |
d9a1f0b4 | 363 | * @tag: Tag of file to remove |
88d7ebe5 | 364 | * |
d9a1f0b4 | 365 | * Search the list in @node whether @tag is currently on the list of allowed |
88d7ebe5 DH |
366 | * open-files (see drm_vma_node_allow()). |
367 | * | |
368 | * This is locked against concurrent access internally. | |
369 | * | |
370 | * RETURNS: | |
371 | * true iff @filp is on the list | |
372 | */ | |
373 | bool drm_vma_node_is_allowed(struct drm_vma_offset_node *node, | |
d9a1f0b4 | 374 | struct drm_file *tag) |
88d7ebe5 DH |
375 | { |
376 | struct drm_vma_offset_file *entry; | |
377 | struct rb_node *iter; | |
378 | ||
379 | read_lock(&node->vm_lock); | |
380 | ||
381 | iter = node->vm_files.rb_node; | |
382 | while (likely(iter)) { | |
383 | entry = rb_entry(iter, struct drm_vma_offset_file, vm_rb); | |
d9a1f0b4 | 384 | if (tag == entry->vm_tag) |
88d7ebe5 | 385 | break; |
d9a1f0b4 | 386 | else if (tag > entry->vm_tag) |
88d7ebe5 DH |
387 | iter = iter->rb_right; |
388 | else | |
389 | iter = iter->rb_left; | |
390 | } | |
391 | ||
392 | read_unlock(&node->vm_lock); | |
393 | ||
394 | return iter; | |
395 | } | |
396 | EXPORT_SYMBOL(drm_vma_node_is_allowed); |