Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /** |
b5e89ed5 | 2 | * \file drm_lock.c |
1da177e4 | 3 | * IOCTLs for locking |
b5e89ed5 | 4 | * |
1da177e4 LT |
5 | * \author Rickard E. (Rik) Faith <faith@valinux.com> |
6 | * \author Gareth Hughes <gareth@valinux.com> | |
7 | */ | |
8 | ||
9 | /* | |
10 | * Created: Tue Feb 2 08:37:54 1999 by faith@valinux.com | |
11 | * | |
12 | * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas. | |
13 | * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California. | |
14 | * All Rights Reserved. | |
15 | * | |
16 | * Permission is hereby granted, free of charge, to any person obtaining a | |
17 | * copy of this software and associated documentation files (the "Software"), | |
18 | * to deal in the Software without restriction, including without limitation | |
19 | * the rights to use, copy, modify, merge, publish, distribute, sublicense, | |
20 | * and/or sell copies of the Software, and to permit persons to whom the | |
21 | * Software is furnished to do so, subject to the following conditions: | |
22 | * | |
23 | * The above copyright notice and this permission notice (including the next | |
24 | * paragraph) shall be included in all copies or substantial portions of the | |
25 | * Software. | |
26 | * | |
27 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
28 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
29 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL | |
30 | * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR | |
31 | * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, | |
32 | * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR | |
33 | * OTHER DEALINGS IN THE SOFTWARE. | |
34 | */ | |
35 | ||
5c2a5ce6 | 36 | #include <linux/export.h> |
760285e7 | 37 | #include <drm/drmP.h> |
1da177e4 | 38 | |
c94f7029 DA |
39 | static int drm_notifier(void *priv); |
40 | ||
4ac5ec40 DV |
41 | static int drm_lock_take(struct drm_lock_data *lock_data, unsigned int context); |
42 | ||
b5e89ed5 | 43 | /** |
1da177e4 LT |
44 | * Lock ioctl. |
45 | * | |
46 | * \param inode device inode. | |
6c340eac | 47 | * \param file_priv DRM file private. |
1da177e4 LT |
48 | * \param cmd command. |
49 | * \param arg user argument, pointing to a drm_lock structure. | |
50 | * \return zero on success or negative number on failure. | |
51 | * | |
52 | * Add the current task to the lock wait queue, and attempt to take to lock. | |
53 | */ | |
c153f45f | 54 | int drm_lock(struct drm_device *dev, void *data, struct drm_file *file_priv) |
1da177e4 | 55 | { |
b5e89ed5 | 56 | DECLARE_WAITQUEUE(entry, current); |
c153f45f | 57 | struct drm_lock *lock = data; |
7c1c2871 | 58 | struct drm_master *master = file_priv->master; |
b5e89ed5 | 59 | int ret = 0; |
1da177e4 | 60 | |
6c340eac | 61 | ++file_priv->lock_count; |
1da177e4 | 62 | |
c153f45f | 63 | if (lock->context == DRM_KERNEL_CONTEXT) { |
b5e89ed5 | 64 | DRM_ERROR("Process %d using kernel context %d\n", |
ba25f9dc | 65 | task_pid_nr(current), lock->context); |
b5e89ed5 DA |
66 | return -EINVAL; |
67 | } | |
1da177e4 | 68 | |
b5e89ed5 | 69 | DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n", |
ba25f9dc | 70 | lock->context, task_pid_nr(current), |
7c1c2871 | 71 | master->lock.hw_lock->lock, lock->flags); |
1da177e4 | 72 | |
7c1c2871 DA |
73 | add_wait_queue(&master->lock.lock_queue, &entry); |
74 | spin_lock_bh(&master->lock.spinlock); | |
75 | master->lock.user_waiters++; | |
76 | spin_unlock_bh(&master->lock.spinlock); | |
77 | ||
1da177e4 LT |
78 | for (;;) { |
79 | __set_current_state(TASK_INTERRUPTIBLE); | |
7c1c2871 | 80 | if (!master->lock.hw_lock) { |
1da177e4 | 81 | /* Device has been unregistered */ |
fda714c2 | 82 | send_sig(SIGTERM, current, 0); |
1da177e4 LT |
83 | ret = -EINTR; |
84 | break; | |
85 | } | |
7c1c2871 DA |
86 | if (drm_lock_take(&master->lock, lock->context)) { |
87 | master->lock.file_priv = file_priv; | |
88 | master->lock.lock_time = jiffies; | |
b5e89ed5 DA |
89 | atomic_inc(&dev->counts[_DRM_STAT_LOCKS]); |
90 | break; /* Got lock */ | |
1da177e4 | 91 | } |
b5e89ed5 | 92 | |
1da177e4 | 93 | /* Contention */ |
08f2e669 | 94 | mutex_unlock(&drm_global_mutex); |
1da177e4 | 95 | schedule(); |
08f2e669 | 96 | mutex_lock(&drm_global_mutex); |
b5e89ed5 | 97 | if (signal_pending(current)) { |
4d77c88e | 98 | ret = -EINTR; |
1da177e4 LT |
99 | break; |
100 | } | |
101 | } | |
7c1c2871 DA |
102 | spin_lock_bh(&master->lock.spinlock); |
103 | master->lock.user_waiters--; | |
104 | spin_unlock_bh(&master->lock.spinlock); | |
1da177e4 | 105 | __set_current_state(TASK_RUNNING); |
7c1c2871 | 106 | remove_wait_queue(&master->lock.lock_queue, &entry); |
1da177e4 | 107 | |
c153f45f EA |
108 | DRM_DEBUG("%d %s\n", lock->context, |
109 | ret ? "interrupted" : "has lock"); | |
040ac320 | 110 | if (ret) return ret; |
d985c108 | 111 | |
3e5fc80a DA |
112 | /* don't set the block all signals on the master process for now |
113 | * really probably not the correct answer but lets us debug xkb | |
114 | * xserver for now */ | |
7c1c2871 | 115 | if (!file_priv->is_master) { |
3e5fc80a DA |
116 | sigemptyset(&dev->sigmask); |
117 | sigaddset(&dev->sigmask, SIGSTOP); | |
118 | sigaddset(&dev->sigmask, SIGTSTP); | |
119 | sigaddset(&dev->sigmask, SIGTTIN); | |
120 | sigaddset(&dev->sigmask, SIGTTOU); | |
121 | dev->sigdata.context = lock->context; | |
7c1c2871 | 122 | dev->sigdata.lock = master->lock.hw_lock; |
3e5fc80a DA |
123 | block_all_signals(drm_notifier, &dev->sigdata, &dev->sigmask); |
124 | } | |
b5e89ed5 | 125 | |
c153f45f EA |
126 | if (dev->driver->dma_quiescent && (lock->flags & _DRM_LOCK_QUIESCENT)) |
127 | { | |
d985c108 | 128 | if (dev->driver->dma_quiescent(dev)) { |
c153f45f EA |
129 | DRM_DEBUG("%d waiting for DMA quiescent\n", |
130 | lock->context); | |
20caafa6 | 131 | return -EBUSY; |
d985c108 DA |
132 | } |
133 | } | |
b5e89ed5 | 134 | |
d985c108 | 135 | return 0; |
1da177e4 LT |
136 | } |
137 | ||
b5e89ed5 | 138 | /** |
1da177e4 LT |
139 | * Unlock ioctl. |
140 | * | |
141 | * \param inode device inode. | |
6c340eac | 142 | * \param file_priv DRM file private. |
1da177e4 LT |
143 | * \param cmd command. |
144 | * \param arg user argument, pointing to a drm_lock structure. | |
145 | * \return zero on success or negative number on failure. | |
146 | * | |
147 | * Transfer and free the lock. | |
148 | */ | |
c153f45f | 149 | int drm_unlock(struct drm_device *dev, void *data, struct drm_file *file_priv) |
1da177e4 | 150 | { |
c153f45f | 151 | struct drm_lock *lock = data; |
45ff46c5 | 152 | struct drm_master *master = file_priv->master; |
1da177e4 | 153 | |
c153f45f | 154 | if (lock->context == DRM_KERNEL_CONTEXT) { |
b5e89ed5 | 155 | DRM_ERROR("Process %d using kernel context %d\n", |
ba25f9dc | 156 | task_pid_nr(current), lock->context); |
1da177e4 LT |
157 | return -EINVAL; |
158 | } | |
159 | ||
b5e89ed5 | 160 | atomic_inc(&dev->counts[_DRM_STAT_UNLOCKS]); |
1da177e4 | 161 | |
45ff46c5 DV |
162 | if (drm_lock_free(&master->lock, lock->context)) { |
163 | /* FIXME: Should really bail out here. */ | |
164 | } | |
165 | ||
1da177e4 LT |
166 | unblock_all_signals(); |
167 | return 0; | |
168 | } | |
169 | ||
170 | /** | |
171 | * Take the heavyweight lock. | |
172 | * | |
173 | * \param lock lock pointer. | |
174 | * \param context locking context. | |
175 | * \return one if the lock is held, or zero otherwise. | |
176 | * | |
177 | * Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction. | |
178 | */ | |
4ac5ec40 | 179 | static |
55910517 | 180 | int drm_lock_take(struct drm_lock_data *lock_data, |
040ac320 | 181 | unsigned int context) |
1da177e4 LT |
182 | { |
183 | unsigned int old, new, prev; | |
040ac320 | 184 | volatile unsigned int *lock = &lock_data->hw_lock->lock; |
1da177e4 | 185 | |
f116cc56 | 186 | spin_lock_bh(&lock_data->spinlock); |
1da177e4 LT |
187 | do { |
188 | old = *lock; | |
b5e89ed5 DA |
189 | if (old & _DRM_LOCK_HELD) |
190 | new = old | _DRM_LOCK_CONT; | |
040ac320 TH |
191 | else { |
192 | new = context | _DRM_LOCK_HELD | | |
193 | ((lock_data->user_waiters + lock_data->kernel_waiters > 1) ? | |
194 | _DRM_LOCK_CONT : 0); | |
195 | } | |
1da177e4 LT |
196 | prev = cmpxchg(lock, old, new); |
197 | } while (prev != old); | |
f116cc56 | 198 | spin_unlock_bh(&lock_data->spinlock); |
040ac320 | 199 | |
1da177e4 LT |
200 | if (_DRM_LOCKING_CONTEXT(old) == context) { |
201 | if (old & _DRM_LOCK_HELD) { | |
202 | if (context != DRM_KERNEL_CONTEXT) { | |
203 | DRM_ERROR("%d holds heavyweight lock\n", | |
204 | context); | |
205 | } | |
206 | return 0; | |
207 | } | |
208 | } | |
040ac320 TH |
209 | |
210 | if ((_DRM_LOCKING_CONTEXT(new)) == context && (new & _DRM_LOCK_HELD)) { | |
b5e89ed5 | 211 | /* Have lock */ |
1da177e4 LT |
212 | return 1; |
213 | } | |
214 | return 0; | |
215 | } | |
216 | ||
217 | /** | |
218 | * This takes a lock forcibly and hands it to context. Should ONLY be used | |
b5e89ed5 DA |
219 | * inside *_unlock to give lock to kernel before calling *_dma_schedule. |
220 | * | |
1da177e4 LT |
221 | * \param dev DRM device. |
222 | * \param lock lock pointer. | |
223 | * \param context locking context. | |
224 | * \return always one. | |
225 | * | |
226 | * Resets the lock file pointer. | |
227 | * Marks the lock as held by the given context, via the \p cmpxchg instruction. | |
228 | */ | |
55910517 | 229 | static int drm_lock_transfer(struct drm_lock_data *lock_data, |
c94f7029 | 230 | unsigned int context) |
1da177e4 LT |
231 | { |
232 | unsigned int old, new, prev; | |
040ac320 | 233 | volatile unsigned int *lock = &lock_data->hw_lock->lock; |
1da177e4 | 234 | |
6c340eac | 235 | lock_data->file_priv = NULL; |
1da177e4 | 236 | do { |
b5e89ed5 DA |
237 | old = *lock; |
238 | new = context | _DRM_LOCK_HELD; | |
1da177e4 LT |
239 | prev = cmpxchg(lock, old, new); |
240 | } while (prev != old); | |
241 | return 1; | |
242 | } | |
243 | ||
244 | /** | |
245 | * Free lock. | |
b5e89ed5 | 246 | * |
1da177e4 LT |
247 | * \param dev DRM device. |
248 | * \param lock lock. | |
249 | * \param context context. | |
b5e89ed5 | 250 | * |
1da177e4 LT |
251 | * Resets the lock file pointer. |
252 | * Marks the lock as not held, via the \p cmpxchg instruction. Wakes any task | |
253 | * waiting on the lock queue. | |
254 | */ | |
55910517 | 255 | int drm_lock_free(struct drm_lock_data *lock_data, unsigned int context) |
1da177e4 LT |
256 | { |
257 | unsigned int old, new, prev; | |
040ac320 TH |
258 | volatile unsigned int *lock = &lock_data->hw_lock->lock; |
259 | ||
f116cc56 | 260 | spin_lock_bh(&lock_data->spinlock); |
040ac320 TH |
261 | if (lock_data->kernel_waiters != 0) { |
262 | drm_lock_transfer(lock_data, 0); | |
263 | lock_data->idle_has_lock = 1; | |
f116cc56 | 264 | spin_unlock_bh(&lock_data->spinlock); |
040ac320 TH |
265 | return 1; |
266 | } | |
f116cc56 | 267 | spin_unlock_bh(&lock_data->spinlock); |
1da177e4 | 268 | |
1da177e4 | 269 | do { |
b5e89ed5 | 270 | old = *lock; |
040ac320 | 271 | new = _DRM_LOCKING_CONTEXT(old); |
1da177e4 LT |
272 | prev = cmpxchg(lock, old, new); |
273 | } while (prev != old); | |
040ac320 | 274 | |
1da177e4 LT |
275 | if (_DRM_LOCK_IS_HELD(old) && _DRM_LOCKING_CONTEXT(old) != context) { |
276 | DRM_ERROR("%d freed heavyweight lock held by %d\n", | |
b5e89ed5 | 277 | context, _DRM_LOCKING_CONTEXT(old)); |
1da177e4 LT |
278 | return 1; |
279 | } | |
040ac320 | 280 | wake_up_interruptible(&lock_data->lock_queue); |
1da177e4 LT |
281 | return 0; |
282 | } | |
283 | ||
284 | /** | |
285 | * If we get here, it means that the process has called DRM_IOCTL_LOCK | |
286 | * without calling DRM_IOCTL_UNLOCK. | |
287 | * | |
288 | * If the lock is not held, then let the signal proceed as usual. If the lock | |
289 | * is held, then set the contended flag and keep the signal blocked. | |
290 | * | |
291 | * \param priv pointer to a drm_sigdata structure. | |
292 | * \return one if the signal should be delivered normally, or zero if the | |
293 | * signal should be blocked. | |
294 | */ | |
c94f7029 | 295 | static int drm_notifier(void *priv) |
1da177e4 | 296 | { |
55910517 | 297 | struct drm_sigdata *s = (struct drm_sigdata *) priv; |
b5e89ed5 | 298 | unsigned int old, new, prev; |
1da177e4 | 299 | |
b5e89ed5 | 300 | /* Allow signal delivery if lock isn't held */ |
1da177e4 | 301 | if (!s->lock || !_DRM_LOCK_IS_HELD(s->lock->lock) |
b5e89ed5 DA |
302 | || _DRM_LOCKING_CONTEXT(s->lock->lock) != s->context) |
303 | return 1; | |
1da177e4 | 304 | |
b5e89ed5 DA |
305 | /* Otherwise, set flag to force call to |
306 | drmUnlock */ | |
1da177e4 | 307 | do { |
b5e89ed5 DA |
308 | old = s->lock->lock; |
309 | new = old | _DRM_LOCK_CONT; | |
1da177e4 LT |
310 | prev = cmpxchg(&s->lock->lock, old, new); |
311 | } while (prev != old); | |
312 | return 0; | |
313 | } | |
040ac320 TH |
314 | |
315 | /** | |
316 | * This function returns immediately and takes the hw lock | |
317 | * with the kernel context if it is free, otherwise it gets the highest priority when and if | |
318 | * it is eventually released. | |
319 | * | |
320 | * This guarantees that the kernel will _eventually_ have the lock _unless_ it is held | |
321 | * by a blocked process. (In the latter case an explicit wait for the hardware lock would cause | |
322 | * a deadlock, which is why the "idlelock" was invented). | |
323 | * | |
324 | * This should be sufficient to wait for GPU idle without | |
325 | * having to worry about starvation. | |
326 | */ | |
327 | ||
55910517 | 328 | void drm_idlelock_take(struct drm_lock_data *lock_data) |
040ac320 | 329 | { |
4a1b0714 | 330 | int ret; |
040ac320 | 331 | |
f116cc56 | 332 | spin_lock_bh(&lock_data->spinlock); |
040ac320 TH |
333 | lock_data->kernel_waiters++; |
334 | if (!lock_data->idle_has_lock) { | |
335 | ||
f116cc56 | 336 | spin_unlock_bh(&lock_data->spinlock); |
040ac320 | 337 | ret = drm_lock_take(lock_data, DRM_KERNEL_CONTEXT); |
f116cc56 | 338 | spin_lock_bh(&lock_data->spinlock); |
040ac320 TH |
339 | |
340 | if (ret == 1) | |
341 | lock_data->idle_has_lock = 1; | |
342 | } | |
f116cc56 | 343 | spin_unlock_bh(&lock_data->spinlock); |
040ac320 | 344 | } |
5c2a5ce6 | 345 | EXPORT_SYMBOL(drm_idlelock_take); |
040ac320 | 346 | |
55910517 | 347 | void drm_idlelock_release(struct drm_lock_data *lock_data) |
040ac320 TH |
348 | { |
349 | unsigned int old, prev; | |
350 | volatile unsigned int *lock = &lock_data->hw_lock->lock; | |
351 | ||
f116cc56 | 352 | spin_lock_bh(&lock_data->spinlock); |
040ac320 TH |
353 | if (--lock_data->kernel_waiters == 0) { |
354 | if (lock_data->idle_has_lock) { | |
355 | do { | |
356 | old = *lock; | |
357 | prev = cmpxchg(lock, old, DRM_KERNEL_CONTEXT); | |
358 | } while (prev != old); | |
359 | wake_up_interruptible(&lock_data->lock_queue); | |
360 | lock_data->idle_has_lock = 0; | |
361 | } | |
362 | } | |
f116cc56 | 363 | spin_unlock_bh(&lock_data->spinlock); |
040ac320 | 364 | } |
5c2a5ce6 | 365 | EXPORT_SYMBOL(drm_idlelock_release); |
040ac320 | 366 | |
c153f45f | 367 | int drm_i_have_hw_lock(struct drm_device *dev, struct drm_file *file_priv) |
040ac320 | 368 | { |
7c1c2871 DA |
369 | struct drm_master *master = file_priv->master; |
370 | return (file_priv->lock_count && master->lock.hw_lock && | |
371 | _DRM_LOCK_IS_HELD(master->lock.hw_lock->lock) && | |
372 | master->lock.file_priv == file_priv); | |
040ac320 | 373 | } |