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 | ||
36 | #include "drmP.h" | |
37 | ||
c94f7029 DA |
38 | static int drm_notifier(void *priv); |
39 | ||
b5e89ed5 | 40 | /** |
1da177e4 LT |
41 | * Lock ioctl. |
42 | * | |
43 | * \param inode device inode. | |
6c340eac | 44 | * \param file_priv DRM file private. |
1da177e4 LT |
45 | * \param cmd command. |
46 | * \param arg user argument, pointing to a drm_lock structure. | |
47 | * \return zero on success or negative number on failure. | |
48 | * | |
49 | * Add the current task to the lock wait queue, and attempt to take to lock. | |
50 | */ | |
c153f45f | 51 | int drm_lock(struct drm_device *dev, void *data, struct drm_file *file_priv) |
1da177e4 | 52 | { |
b5e89ed5 | 53 | DECLARE_WAITQUEUE(entry, current); |
c153f45f | 54 | struct drm_lock *lock = data; |
b5e89ed5 | 55 | int ret = 0; |
1da177e4 | 56 | |
6c340eac | 57 | ++file_priv->lock_count; |
1da177e4 | 58 | |
c153f45f | 59 | if (lock->context == DRM_KERNEL_CONTEXT) { |
b5e89ed5 | 60 | DRM_ERROR("Process %d using kernel context %d\n", |
c153f45f | 61 | current->pid, lock->context); |
b5e89ed5 DA |
62 | return -EINVAL; |
63 | } | |
1da177e4 | 64 | |
b5e89ed5 | 65 | DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n", |
c153f45f EA |
66 | lock->context, current->pid, |
67 | dev->lock.hw_lock->lock, lock->flags); | |
1da177e4 LT |
68 | |
69 | if (drm_core_check_feature(dev, DRIVER_DMA_QUEUE)) | |
c153f45f | 70 | if (lock->context < 0) |
1da177e4 LT |
71 | return -EINVAL; |
72 | ||
b5e89ed5 | 73 | add_wait_queue(&dev->lock.lock_queue, &entry); |
040ac320 TH |
74 | spin_lock(&dev->lock.spinlock); |
75 | dev->lock.user_waiters++; | |
76 | spin_unlock(&dev->lock.spinlock); | |
1da177e4 LT |
77 | for (;;) { |
78 | __set_current_state(TASK_INTERRUPTIBLE); | |
b5e89ed5 | 79 | if (!dev->lock.hw_lock) { |
1da177e4 LT |
80 | /* Device has been unregistered */ |
81 | ret = -EINTR; | |
82 | break; | |
83 | } | |
c153f45f | 84 | if (drm_lock_take(&dev->lock, lock->context)) { |
6c340eac | 85 | dev->lock.file_priv = file_priv; |
1da177e4 | 86 | dev->lock.lock_time = jiffies; |
b5e89ed5 DA |
87 | atomic_inc(&dev->counts[_DRM_STAT_LOCKS]); |
88 | break; /* Got lock */ | |
1da177e4 | 89 | } |
b5e89ed5 | 90 | |
1da177e4 LT |
91 | /* Contention */ |
92 | schedule(); | |
b5e89ed5 | 93 | if (signal_pending(current)) { |
1da177e4 LT |
94 | ret = -ERESTARTSYS; |
95 | break; | |
96 | } | |
97 | } | |
040ac320 TH |
98 | spin_lock(&dev->lock.spinlock); |
99 | dev->lock.user_waiters--; | |
100 | spin_unlock(&dev->lock.spinlock); | |
1da177e4 | 101 | __set_current_state(TASK_RUNNING); |
b5e89ed5 | 102 | remove_wait_queue(&dev->lock.lock_queue, &entry); |
1da177e4 | 103 | |
c153f45f EA |
104 | DRM_DEBUG("%d %s\n", lock->context, |
105 | ret ? "interrupted" : "has lock"); | |
040ac320 | 106 | if (ret) return ret; |
d985c108 | 107 | |
b5e89ed5 DA |
108 | sigemptyset(&dev->sigmask); |
109 | sigaddset(&dev->sigmask, SIGSTOP); | |
110 | sigaddset(&dev->sigmask, SIGTSTP); | |
111 | sigaddset(&dev->sigmask, SIGTTIN); | |
112 | sigaddset(&dev->sigmask, SIGTTOU); | |
c153f45f | 113 | dev->sigdata.context = lock->context; |
b5e89ed5 DA |
114 | dev->sigdata.lock = dev->lock.hw_lock; |
115 | block_all_signals(drm_notifier, &dev->sigdata, &dev->sigmask); | |
116 | ||
c153f45f | 117 | if (dev->driver->dma_ready && (lock->flags & _DRM_LOCK_READY)) |
1da177e4 | 118 | dev->driver->dma_ready(dev); |
b5e89ed5 | 119 | |
c153f45f EA |
120 | if (dev->driver->dma_quiescent && (lock->flags & _DRM_LOCK_QUIESCENT)) |
121 | { | |
d985c108 | 122 | if (dev->driver->dma_quiescent(dev)) { |
c153f45f EA |
123 | DRM_DEBUG("%d waiting for DMA quiescent\n", |
124 | lock->context); | |
20caafa6 | 125 | return -EBUSY; |
d985c108 DA |
126 | } |
127 | } | |
b5e89ed5 DA |
128 | |
129 | if (dev->driver->kernel_context_switch && | |
c153f45f | 130 | dev->last_context != lock->context) { |
b5e89ed5 | 131 | dev->driver->kernel_context_switch(dev, dev->last_context, |
c153f45f | 132 | lock->context); |
1da177e4 | 133 | } |
040ac320 | 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; |
5c2df2bf | 152 | unsigned long irqflags; |
1da177e4 | 153 | |
c153f45f | 154 | if (lock->context == DRM_KERNEL_CONTEXT) { |
b5e89ed5 | 155 | DRM_ERROR("Process %d using kernel context %d\n", |
c153f45f | 156 | current->pid, lock->context); |
1da177e4 LT |
157 | return -EINVAL; |
158 | } | |
159 | ||
2e54a007 MCA |
160 | spin_lock_irqsave(&dev->tasklet_lock, irqflags); |
161 | ||
162 | if (dev->locked_tasklet_func) { | |
163 | dev->locked_tasklet_func(dev); | |
164 | ||
165 | dev->locked_tasklet_func = NULL; | |
166 | } | |
167 | ||
168 | spin_unlock_irqrestore(&dev->tasklet_lock, irqflags); | |
169 | ||
b5e89ed5 | 170 | atomic_inc(&dev->counts[_DRM_STAT_UNLOCKS]); |
1da177e4 LT |
171 | |
172 | /* kernel_context_switch isn't used by any of the x86 drm | |
173 | * modules but is required by the Sparc driver. | |
174 | */ | |
175 | if (dev->driver->kernel_context_switch_unlock) | |
0c4dd906 | 176 | dev->driver->kernel_context_switch_unlock(dev); |
1da177e4 | 177 | else { |
c153f45f | 178 | if (drm_lock_free(&dev->lock,lock->context)) { |
040ac320 | 179 | /* FIXME: Should really bail out here. */ |
1da177e4 LT |
180 | } |
181 | } | |
182 | ||
183 | unblock_all_signals(); | |
184 | return 0; | |
185 | } | |
186 | ||
187 | /** | |
188 | * Take the heavyweight lock. | |
189 | * | |
190 | * \param lock lock pointer. | |
191 | * \param context locking context. | |
192 | * \return one if the lock is held, or zero otherwise. | |
193 | * | |
194 | * Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction. | |
195 | */ | |
55910517 | 196 | int drm_lock_take(struct drm_lock_data *lock_data, |
040ac320 | 197 | unsigned int context) |
1da177e4 LT |
198 | { |
199 | unsigned int old, new, prev; | |
040ac320 | 200 | volatile unsigned int *lock = &lock_data->hw_lock->lock; |
1da177e4 | 201 | |
040ac320 | 202 | spin_lock(&lock_data->spinlock); |
1da177e4 LT |
203 | do { |
204 | old = *lock; | |
b5e89ed5 DA |
205 | if (old & _DRM_LOCK_HELD) |
206 | new = old | _DRM_LOCK_CONT; | |
040ac320 TH |
207 | else { |
208 | new = context | _DRM_LOCK_HELD | | |
209 | ((lock_data->user_waiters + lock_data->kernel_waiters > 1) ? | |
210 | _DRM_LOCK_CONT : 0); | |
211 | } | |
1da177e4 LT |
212 | prev = cmpxchg(lock, old, new); |
213 | } while (prev != old); | |
040ac320 TH |
214 | spin_unlock(&lock_data->spinlock); |
215 | ||
1da177e4 LT |
216 | if (_DRM_LOCKING_CONTEXT(old) == context) { |
217 | if (old & _DRM_LOCK_HELD) { | |
218 | if (context != DRM_KERNEL_CONTEXT) { | |
219 | DRM_ERROR("%d holds heavyweight lock\n", | |
220 | context); | |
221 | } | |
222 | return 0; | |
223 | } | |
224 | } | |
040ac320 TH |
225 | |
226 | if ((_DRM_LOCKING_CONTEXT(new)) == context && (new & _DRM_LOCK_HELD)) { | |
b5e89ed5 | 227 | /* Have lock */ |
1da177e4 LT |
228 | return 1; |
229 | } | |
230 | return 0; | |
231 | } | |
232 | ||
233 | /** | |
234 | * This takes a lock forcibly and hands it to context. Should ONLY be used | |
b5e89ed5 DA |
235 | * inside *_unlock to give lock to kernel before calling *_dma_schedule. |
236 | * | |
1da177e4 LT |
237 | * \param dev DRM device. |
238 | * \param lock lock pointer. | |
239 | * \param context locking context. | |
240 | * \return always one. | |
241 | * | |
242 | * Resets the lock file pointer. | |
243 | * Marks the lock as held by the given context, via the \p cmpxchg instruction. | |
244 | */ | |
55910517 | 245 | static int drm_lock_transfer(struct drm_lock_data *lock_data, |
c94f7029 | 246 | unsigned int context) |
1da177e4 LT |
247 | { |
248 | unsigned int old, new, prev; | |
040ac320 | 249 | volatile unsigned int *lock = &lock_data->hw_lock->lock; |
1da177e4 | 250 | |
6c340eac | 251 | lock_data->file_priv = NULL; |
1da177e4 | 252 | do { |
b5e89ed5 DA |
253 | old = *lock; |
254 | new = context | _DRM_LOCK_HELD; | |
1da177e4 LT |
255 | prev = cmpxchg(lock, old, new); |
256 | } while (prev != old); | |
257 | return 1; | |
258 | } | |
259 | ||
260 | /** | |
261 | * Free lock. | |
b5e89ed5 | 262 | * |
1da177e4 LT |
263 | * \param dev DRM device. |
264 | * \param lock lock. | |
265 | * \param context context. | |
b5e89ed5 | 266 | * |
1da177e4 LT |
267 | * Resets the lock file pointer. |
268 | * Marks the lock as not held, via the \p cmpxchg instruction. Wakes any task | |
269 | * waiting on the lock queue. | |
270 | */ | |
55910517 | 271 | int drm_lock_free(struct drm_lock_data *lock_data, unsigned int context) |
1da177e4 LT |
272 | { |
273 | unsigned int old, new, prev; | |
040ac320 TH |
274 | volatile unsigned int *lock = &lock_data->hw_lock->lock; |
275 | ||
276 | spin_lock(&lock_data->spinlock); | |
277 | if (lock_data->kernel_waiters != 0) { | |
278 | drm_lock_transfer(lock_data, 0); | |
279 | lock_data->idle_has_lock = 1; | |
280 | spin_unlock(&lock_data->spinlock); | |
281 | return 1; | |
282 | } | |
283 | spin_unlock(&lock_data->spinlock); | |
1da177e4 | 284 | |
1da177e4 | 285 | do { |
b5e89ed5 | 286 | old = *lock; |
040ac320 | 287 | new = _DRM_LOCKING_CONTEXT(old); |
1da177e4 LT |
288 | prev = cmpxchg(lock, old, new); |
289 | } while (prev != old); | |
040ac320 | 290 | |
1da177e4 LT |
291 | if (_DRM_LOCK_IS_HELD(old) && _DRM_LOCKING_CONTEXT(old) != context) { |
292 | DRM_ERROR("%d freed heavyweight lock held by %d\n", | |
b5e89ed5 | 293 | context, _DRM_LOCKING_CONTEXT(old)); |
1da177e4 LT |
294 | return 1; |
295 | } | |
040ac320 | 296 | wake_up_interruptible(&lock_data->lock_queue); |
1da177e4 LT |
297 | return 0; |
298 | } | |
299 | ||
300 | /** | |
301 | * If we get here, it means that the process has called DRM_IOCTL_LOCK | |
302 | * without calling DRM_IOCTL_UNLOCK. | |
303 | * | |
304 | * If the lock is not held, then let the signal proceed as usual. If the lock | |
305 | * is held, then set the contended flag and keep the signal blocked. | |
306 | * | |
307 | * \param priv pointer to a drm_sigdata structure. | |
308 | * \return one if the signal should be delivered normally, or zero if the | |
309 | * signal should be blocked. | |
310 | */ | |
c94f7029 | 311 | static int drm_notifier(void *priv) |
1da177e4 | 312 | { |
55910517 | 313 | struct drm_sigdata *s = (struct drm_sigdata *) priv; |
b5e89ed5 | 314 | unsigned int old, new, prev; |
1da177e4 | 315 | |
b5e89ed5 | 316 | /* Allow signal delivery if lock isn't held */ |
1da177e4 | 317 | if (!s->lock || !_DRM_LOCK_IS_HELD(s->lock->lock) |
b5e89ed5 DA |
318 | || _DRM_LOCKING_CONTEXT(s->lock->lock) != s->context) |
319 | return 1; | |
1da177e4 | 320 | |
b5e89ed5 DA |
321 | /* Otherwise, set flag to force call to |
322 | drmUnlock */ | |
1da177e4 | 323 | do { |
b5e89ed5 DA |
324 | old = s->lock->lock; |
325 | new = old | _DRM_LOCK_CONT; | |
1da177e4 LT |
326 | prev = cmpxchg(&s->lock->lock, old, new); |
327 | } while (prev != old); | |
328 | return 0; | |
329 | } | |
040ac320 TH |
330 | |
331 | /** | |
332 | * This function returns immediately and takes the hw lock | |
333 | * with the kernel context if it is free, otherwise it gets the highest priority when and if | |
334 | * it is eventually released. | |
335 | * | |
336 | * This guarantees that the kernel will _eventually_ have the lock _unless_ it is held | |
337 | * by a blocked process. (In the latter case an explicit wait for the hardware lock would cause | |
338 | * a deadlock, which is why the "idlelock" was invented). | |
339 | * | |
340 | * This should be sufficient to wait for GPU idle without | |
341 | * having to worry about starvation. | |
342 | */ | |
343 | ||
55910517 | 344 | void drm_idlelock_take(struct drm_lock_data *lock_data) |
040ac320 TH |
345 | { |
346 | int ret = 0; | |
347 | ||
348 | spin_lock(&lock_data->spinlock); | |
349 | lock_data->kernel_waiters++; | |
350 | if (!lock_data->idle_has_lock) { | |
351 | ||
352 | spin_unlock(&lock_data->spinlock); | |
353 | ret = drm_lock_take(lock_data, DRM_KERNEL_CONTEXT); | |
354 | spin_lock(&lock_data->spinlock); | |
355 | ||
356 | if (ret == 1) | |
357 | lock_data->idle_has_lock = 1; | |
358 | } | |
359 | spin_unlock(&lock_data->spinlock); | |
360 | } | |
361 | EXPORT_SYMBOL(drm_idlelock_take); | |
362 | ||
55910517 | 363 | void drm_idlelock_release(struct drm_lock_data *lock_data) |
040ac320 TH |
364 | { |
365 | unsigned int old, prev; | |
366 | volatile unsigned int *lock = &lock_data->hw_lock->lock; | |
367 | ||
368 | spin_lock(&lock_data->spinlock); | |
369 | if (--lock_data->kernel_waiters == 0) { | |
370 | if (lock_data->idle_has_lock) { | |
371 | do { | |
372 | old = *lock; | |
373 | prev = cmpxchg(lock, old, DRM_KERNEL_CONTEXT); | |
374 | } while (prev != old); | |
375 | wake_up_interruptible(&lock_data->lock_queue); | |
376 | lock_data->idle_has_lock = 0; | |
377 | } | |
378 | } | |
379 | spin_unlock(&lock_data->spinlock); | |
380 | } | |
381 | EXPORT_SYMBOL(drm_idlelock_release); | |
382 | ||
383 | ||
c153f45f | 384 | int drm_i_have_hw_lock(struct drm_device *dev, struct drm_file *file_priv) |
040ac320 | 385 | { |
6c340eac | 386 | return (file_priv->lock_count && dev->lock.hw_lock && |
040ac320 | 387 | _DRM_LOCK_IS_HELD(dev->lock.hw_lock->lock) && |
6c340eac | 388 | dev->lock.file_priv == file_priv); |
040ac320 TH |
389 | } |
390 | ||
391 | EXPORT_SYMBOL(drm_i_have_hw_lock); |