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Commit | Line | Data |
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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", |
ba25f9dc | 61 | task_pid_nr(current), 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", |
ba25f9dc | 66 | lock->context, task_pid_nr(current), |
c153f45f | 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); |
f116cc56 | 74 | spin_lock_bh(&dev->lock.spinlock); |
040ac320 | 75 | dev->lock.user_waiters++; |
f116cc56 | 76 | spin_unlock_bh(&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 | } | |
f116cc56 | 98 | spin_lock_bh(&dev->lock.spinlock); |
040ac320 | 99 | dev->lock.user_waiters--; |
f116cc56 | 100 | spin_unlock_bh(&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 | |
3e5fc80a DA |
108 | /* don't set the block all signals on the master process for now |
109 | * really probably not the correct answer but lets us debug xkb | |
110 | * xserver for now */ | |
111 | if (!file_priv->master) { | |
112 | sigemptyset(&dev->sigmask); | |
113 | sigaddset(&dev->sigmask, SIGSTOP); | |
114 | sigaddset(&dev->sigmask, SIGTSTP); | |
115 | sigaddset(&dev->sigmask, SIGTTIN); | |
116 | sigaddset(&dev->sigmask, SIGTTOU); | |
117 | dev->sigdata.context = lock->context; | |
118 | dev->sigdata.lock = dev->lock.hw_lock; | |
119 | block_all_signals(drm_notifier, &dev->sigdata, &dev->sigmask); | |
120 | } | |
b5e89ed5 | 121 | |
c153f45f | 122 | if (dev->driver->dma_ready && (lock->flags & _DRM_LOCK_READY)) |
1da177e4 | 123 | dev->driver->dma_ready(dev); |
b5e89ed5 | 124 | |
c153f45f EA |
125 | if (dev->driver->dma_quiescent && (lock->flags & _DRM_LOCK_QUIESCENT)) |
126 | { | |
d985c108 | 127 | if (dev->driver->dma_quiescent(dev)) { |
c153f45f EA |
128 | DRM_DEBUG("%d waiting for DMA quiescent\n", |
129 | lock->context); | |
20caafa6 | 130 | return -EBUSY; |
d985c108 DA |
131 | } |
132 | } | |
b5e89ed5 DA |
133 | |
134 | if (dev->driver->kernel_context_switch && | |
c153f45f | 135 | dev->last_context != lock->context) { |
b5e89ed5 | 136 | dev->driver->kernel_context_switch(dev, dev->last_context, |
c153f45f | 137 | lock->context); |
1da177e4 | 138 | } |
040ac320 | 139 | |
d985c108 | 140 | return 0; |
1da177e4 LT |
141 | } |
142 | ||
b5e89ed5 | 143 | /** |
1da177e4 LT |
144 | * Unlock ioctl. |
145 | * | |
146 | * \param inode device inode. | |
6c340eac | 147 | * \param file_priv DRM file private. |
1da177e4 LT |
148 | * \param cmd command. |
149 | * \param arg user argument, pointing to a drm_lock structure. | |
150 | * \return zero on success or negative number on failure. | |
151 | * | |
152 | * Transfer and free the lock. | |
153 | */ | |
c153f45f | 154 | int drm_unlock(struct drm_device *dev, void *data, struct drm_file *file_priv) |
1da177e4 | 155 | { |
c153f45f | 156 | struct drm_lock *lock = data; |
1da177e4 | 157 | |
c153f45f | 158 | if (lock->context == DRM_KERNEL_CONTEXT) { |
b5e89ed5 | 159 | DRM_ERROR("Process %d using kernel context %d\n", |
ba25f9dc | 160 | task_pid_nr(current), lock->context); |
1da177e4 LT |
161 | return -EINVAL; |
162 | } | |
163 | ||
b5e89ed5 | 164 | atomic_inc(&dev->counts[_DRM_STAT_UNLOCKS]); |
1da177e4 LT |
165 | |
166 | /* kernel_context_switch isn't used by any of the x86 drm | |
167 | * modules but is required by the Sparc driver. | |
168 | */ | |
169 | if (dev->driver->kernel_context_switch_unlock) | |
0c4dd906 | 170 | dev->driver->kernel_context_switch_unlock(dev); |
1da177e4 | 171 | else { |
c153f45f | 172 | if (drm_lock_free(&dev->lock,lock->context)) { |
040ac320 | 173 | /* FIXME: Should really bail out here. */ |
1da177e4 LT |
174 | } |
175 | } | |
176 | ||
177 | unblock_all_signals(); | |
178 | return 0; | |
179 | } | |
180 | ||
181 | /** | |
182 | * Take the heavyweight lock. | |
183 | * | |
184 | * \param lock lock pointer. | |
185 | * \param context locking context. | |
186 | * \return one if the lock is held, or zero otherwise. | |
187 | * | |
188 | * Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction. | |
189 | */ | |
55910517 | 190 | int drm_lock_take(struct drm_lock_data *lock_data, |
040ac320 | 191 | unsigned int context) |
1da177e4 LT |
192 | { |
193 | unsigned int old, new, prev; | |
040ac320 | 194 | volatile unsigned int *lock = &lock_data->hw_lock->lock; |
1da177e4 | 195 | |
f116cc56 | 196 | spin_lock_bh(&lock_data->spinlock); |
1da177e4 LT |
197 | do { |
198 | old = *lock; | |
b5e89ed5 DA |
199 | if (old & _DRM_LOCK_HELD) |
200 | new = old | _DRM_LOCK_CONT; | |
040ac320 TH |
201 | else { |
202 | new = context | _DRM_LOCK_HELD | | |
203 | ((lock_data->user_waiters + lock_data->kernel_waiters > 1) ? | |
204 | _DRM_LOCK_CONT : 0); | |
205 | } | |
1da177e4 LT |
206 | prev = cmpxchg(lock, old, new); |
207 | } while (prev != old); | |
f116cc56 | 208 | spin_unlock_bh(&lock_data->spinlock); |
040ac320 | 209 | |
1da177e4 LT |
210 | if (_DRM_LOCKING_CONTEXT(old) == context) { |
211 | if (old & _DRM_LOCK_HELD) { | |
212 | if (context != DRM_KERNEL_CONTEXT) { | |
213 | DRM_ERROR("%d holds heavyweight lock\n", | |
214 | context); | |
215 | } | |
216 | return 0; | |
217 | } | |
218 | } | |
040ac320 TH |
219 | |
220 | if ((_DRM_LOCKING_CONTEXT(new)) == context && (new & _DRM_LOCK_HELD)) { | |
b5e89ed5 | 221 | /* Have lock */ |
1da177e4 LT |
222 | return 1; |
223 | } | |
224 | return 0; | |
225 | } | |
9e44af79 | 226 | EXPORT_SYMBOL(drm_lock_take); |
1da177e4 LT |
227 | |
228 | /** | |
229 | * This takes a lock forcibly and hands it to context. Should ONLY be used | |
b5e89ed5 DA |
230 | * inside *_unlock to give lock to kernel before calling *_dma_schedule. |
231 | * | |
1da177e4 LT |
232 | * \param dev DRM device. |
233 | * \param lock lock pointer. | |
234 | * \param context locking context. | |
235 | * \return always one. | |
236 | * | |
237 | * Resets the lock file pointer. | |
238 | * Marks the lock as held by the given context, via the \p cmpxchg instruction. | |
239 | */ | |
55910517 | 240 | static int drm_lock_transfer(struct drm_lock_data *lock_data, |
c94f7029 | 241 | unsigned int context) |
1da177e4 LT |
242 | { |
243 | unsigned int old, new, prev; | |
040ac320 | 244 | volatile unsigned int *lock = &lock_data->hw_lock->lock; |
1da177e4 | 245 | |
6c340eac | 246 | lock_data->file_priv = NULL; |
1da177e4 | 247 | do { |
b5e89ed5 DA |
248 | old = *lock; |
249 | new = context | _DRM_LOCK_HELD; | |
1da177e4 LT |
250 | prev = cmpxchg(lock, old, new); |
251 | } while (prev != old); | |
252 | return 1; | |
253 | } | |
254 | ||
255 | /** | |
256 | * Free lock. | |
b5e89ed5 | 257 | * |
1da177e4 LT |
258 | * \param dev DRM device. |
259 | * \param lock lock. | |
260 | * \param context context. | |
b5e89ed5 | 261 | * |
1da177e4 LT |
262 | * Resets the lock file pointer. |
263 | * Marks the lock as not held, via the \p cmpxchg instruction. Wakes any task | |
264 | * waiting on the lock queue. | |
265 | */ | |
55910517 | 266 | int drm_lock_free(struct drm_lock_data *lock_data, unsigned int context) |
1da177e4 LT |
267 | { |
268 | unsigned int old, new, prev; | |
040ac320 TH |
269 | volatile unsigned int *lock = &lock_data->hw_lock->lock; |
270 | ||
f116cc56 | 271 | spin_lock_bh(&lock_data->spinlock); |
040ac320 TH |
272 | if (lock_data->kernel_waiters != 0) { |
273 | drm_lock_transfer(lock_data, 0); | |
274 | lock_data->idle_has_lock = 1; | |
f116cc56 | 275 | spin_unlock_bh(&lock_data->spinlock); |
040ac320 TH |
276 | return 1; |
277 | } | |
f116cc56 | 278 | spin_unlock_bh(&lock_data->spinlock); |
1da177e4 | 279 | |
1da177e4 | 280 | do { |
b5e89ed5 | 281 | old = *lock; |
040ac320 | 282 | new = _DRM_LOCKING_CONTEXT(old); |
1da177e4 LT |
283 | prev = cmpxchg(lock, old, new); |
284 | } while (prev != old); | |
040ac320 | 285 | |
1da177e4 LT |
286 | if (_DRM_LOCK_IS_HELD(old) && _DRM_LOCKING_CONTEXT(old) != context) { |
287 | DRM_ERROR("%d freed heavyweight lock held by %d\n", | |
b5e89ed5 | 288 | context, _DRM_LOCKING_CONTEXT(old)); |
1da177e4 LT |
289 | return 1; |
290 | } | |
040ac320 | 291 | wake_up_interruptible(&lock_data->lock_queue); |
1da177e4 LT |
292 | return 0; |
293 | } | |
9e44af79 | 294 | EXPORT_SYMBOL(drm_lock_free); |
1da177e4 LT |
295 | |
296 | /** | |
297 | * If we get here, it means that the process has called DRM_IOCTL_LOCK | |
298 | * without calling DRM_IOCTL_UNLOCK. | |
299 | * | |
300 | * If the lock is not held, then let the signal proceed as usual. If the lock | |
301 | * is held, then set the contended flag and keep the signal blocked. | |
302 | * | |
303 | * \param priv pointer to a drm_sigdata structure. | |
304 | * \return one if the signal should be delivered normally, or zero if the | |
305 | * signal should be blocked. | |
306 | */ | |
c94f7029 | 307 | static int drm_notifier(void *priv) |
1da177e4 | 308 | { |
55910517 | 309 | struct drm_sigdata *s = (struct drm_sigdata *) priv; |
b5e89ed5 | 310 | unsigned int old, new, prev; |
1da177e4 | 311 | |
b5e89ed5 | 312 | /* Allow signal delivery if lock isn't held */ |
1da177e4 | 313 | if (!s->lock || !_DRM_LOCK_IS_HELD(s->lock->lock) |
b5e89ed5 DA |
314 | || _DRM_LOCKING_CONTEXT(s->lock->lock) != s->context) |
315 | return 1; | |
1da177e4 | 316 | |
b5e89ed5 DA |
317 | /* Otherwise, set flag to force call to |
318 | drmUnlock */ | |
1da177e4 | 319 | do { |
b5e89ed5 DA |
320 | old = s->lock->lock; |
321 | new = old | _DRM_LOCK_CONT; | |
1da177e4 LT |
322 | prev = cmpxchg(&s->lock->lock, old, new); |
323 | } while (prev != old); | |
324 | return 0; | |
325 | } | |
040ac320 TH |
326 | |
327 | /** | |
328 | * This function returns immediately and takes the hw lock | |
329 | * with the kernel context if it is free, otherwise it gets the highest priority when and if | |
330 | * it is eventually released. | |
331 | * | |
332 | * This guarantees that the kernel will _eventually_ have the lock _unless_ it is held | |
333 | * by a blocked process. (In the latter case an explicit wait for the hardware lock would cause | |
334 | * a deadlock, which is why the "idlelock" was invented). | |
335 | * | |
336 | * This should be sufficient to wait for GPU idle without | |
337 | * having to worry about starvation. | |
338 | */ | |
339 | ||
55910517 | 340 | void drm_idlelock_take(struct drm_lock_data *lock_data) |
040ac320 TH |
341 | { |
342 | int ret = 0; | |
343 | ||
f116cc56 | 344 | spin_lock_bh(&lock_data->spinlock); |
040ac320 TH |
345 | lock_data->kernel_waiters++; |
346 | if (!lock_data->idle_has_lock) { | |
347 | ||
f116cc56 | 348 | spin_unlock_bh(&lock_data->spinlock); |
040ac320 | 349 | ret = drm_lock_take(lock_data, DRM_KERNEL_CONTEXT); |
f116cc56 | 350 | spin_lock_bh(&lock_data->spinlock); |
040ac320 TH |
351 | |
352 | if (ret == 1) | |
353 | lock_data->idle_has_lock = 1; | |
354 | } | |
f116cc56 | 355 | spin_unlock_bh(&lock_data->spinlock); |
040ac320 TH |
356 | } |
357 | EXPORT_SYMBOL(drm_idlelock_take); | |
358 | ||
55910517 | 359 | void drm_idlelock_release(struct drm_lock_data *lock_data) |
040ac320 TH |
360 | { |
361 | unsigned int old, prev; | |
362 | volatile unsigned int *lock = &lock_data->hw_lock->lock; | |
363 | ||
f116cc56 | 364 | spin_lock_bh(&lock_data->spinlock); |
040ac320 TH |
365 | if (--lock_data->kernel_waiters == 0) { |
366 | if (lock_data->idle_has_lock) { | |
367 | do { | |
368 | old = *lock; | |
369 | prev = cmpxchg(lock, old, DRM_KERNEL_CONTEXT); | |
370 | } while (prev != old); | |
371 | wake_up_interruptible(&lock_data->lock_queue); | |
372 | lock_data->idle_has_lock = 0; | |
373 | } | |
374 | } | |
f116cc56 | 375 | spin_unlock_bh(&lock_data->spinlock); |
040ac320 TH |
376 | } |
377 | EXPORT_SYMBOL(drm_idlelock_release); | |
378 | ||
379 | ||
c153f45f | 380 | int drm_i_have_hw_lock(struct drm_device *dev, struct drm_file *file_priv) |
040ac320 | 381 | { |
6c340eac | 382 | return (file_priv->lock_count && dev->lock.hw_lock && |
040ac320 | 383 | _DRM_LOCK_IS_HELD(dev->lock.hw_lock->lock) && |
6c340eac | 384 | dev->lock.file_priv == file_priv); |
040ac320 TH |
385 | } |
386 | ||
387 | EXPORT_SYMBOL(drm_i_have_hw_lock); |