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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 | ||
4ac5ec40 DV |
40 | static int drm_lock_take(struct drm_lock_data *lock_data, unsigned int context); |
41 | ||
b5e89ed5 | 42 | /** |
1da177e4 LT |
43 | * Lock ioctl. |
44 | * | |
45 | * \param inode device inode. | |
6c340eac | 46 | * \param file_priv DRM file private. |
1da177e4 LT |
47 | * \param cmd command. |
48 | * \param arg user argument, pointing to a drm_lock structure. | |
49 | * \return zero on success or negative number on failure. | |
50 | * | |
51 | * Add the current task to the lock wait queue, and attempt to take to lock. | |
52 | */ | |
c153f45f | 53 | int drm_lock(struct drm_device *dev, void *data, struct drm_file *file_priv) |
1da177e4 | 54 | { |
b5e89ed5 | 55 | DECLARE_WAITQUEUE(entry, current); |
c153f45f | 56 | struct drm_lock *lock = data; |
7c1c2871 | 57 | struct drm_master *master = file_priv->master; |
b5e89ed5 | 58 | int ret = 0; |
1da177e4 | 59 | |
6c340eac | 60 | ++file_priv->lock_count; |
1da177e4 | 61 | |
c153f45f | 62 | if (lock->context == DRM_KERNEL_CONTEXT) { |
b5e89ed5 | 63 | DRM_ERROR("Process %d using kernel context %d\n", |
ba25f9dc | 64 | task_pid_nr(current), lock->context); |
b5e89ed5 DA |
65 | return -EINVAL; |
66 | } | |
1da177e4 | 67 | |
b5e89ed5 | 68 | DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n", |
ba25f9dc | 69 | lock->context, task_pid_nr(current), |
7c1c2871 | 70 | master->lock.hw_lock->lock, lock->flags); |
1da177e4 LT |
71 | |
72 | if (drm_core_check_feature(dev, DRIVER_DMA_QUEUE)) | |
c153f45f | 73 | if (lock->context < 0) |
1da177e4 LT |
74 | return -EINVAL; |
75 | ||
7c1c2871 DA |
76 | add_wait_queue(&master->lock.lock_queue, &entry); |
77 | spin_lock_bh(&master->lock.spinlock); | |
78 | master->lock.user_waiters++; | |
79 | spin_unlock_bh(&master->lock.spinlock); | |
80 | ||
1da177e4 LT |
81 | for (;;) { |
82 | __set_current_state(TASK_INTERRUPTIBLE); | |
7c1c2871 | 83 | if (!master->lock.hw_lock) { |
1da177e4 | 84 | /* Device has been unregistered */ |
fda714c2 | 85 | send_sig(SIGTERM, current, 0); |
1da177e4 LT |
86 | ret = -EINTR; |
87 | break; | |
88 | } | |
7c1c2871 DA |
89 | if (drm_lock_take(&master->lock, lock->context)) { |
90 | master->lock.file_priv = file_priv; | |
91 | master->lock.lock_time = jiffies; | |
b5e89ed5 DA |
92 | atomic_inc(&dev->counts[_DRM_STAT_LOCKS]); |
93 | break; /* Got lock */ | |
1da177e4 | 94 | } |
b5e89ed5 | 95 | |
1da177e4 | 96 | /* Contention */ |
08f2e669 | 97 | mutex_unlock(&drm_global_mutex); |
1da177e4 | 98 | schedule(); |
08f2e669 | 99 | mutex_lock(&drm_global_mutex); |
b5e89ed5 | 100 | if (signal_pending(current)) { |
4d77c88e | 101 | ret = -EINTR; |
1da177e4 LT |
102 | break; |
103 | } | |
104 | } | |
7c1c2871 DA |
105 | spin_lock_bh(&master->lock.spinlock); |
106 | master->lock.user_waiters--; | |
107 | spin_unlock_bh(&master->lock.spinlock); | |
1da177e4 | 108 | __set_current_state(TASK_RUNNING); |
7c1c2871 | 109 | remove_wait_queue(&master->lock.lock_queue, &entry); |
1da177e4 | 110 | |
c153f45f EA |
111 | DRM_DEBUG("%d %s\n", lock->context, |
112 | ret ? "interrupted" : "has lock"); | |
040ac320 | 113 | if (ret) return ret; |
d985c108 | 114 | |
3e5fc80a DA |
115 | /* don't set the block all signals on the master process for now |
116 | * really probably not the correct answer but lets us debug xkb | |
117 | * xserver for now */ | |
7c1c2871 | 118 | if (!file_priv->is_master) { |
3e5fc80a DA |
119 | sigemptyset(&dev->sigmask); |
120 | sigaddset(&dev->sigmask, SIGSTOP); | |
121 | sigaddset(&dev->sigmask, SIGTSTP); | |
122 | sigaddset(&dev->sigmask, SIGTTIN); | |
123 | sigaddset(&dev->sigmask, SIGTTOU); | |
124 | dev->sigdata.context = lock->context; | |
7c1c2871 | 125 | dev->sigdata.lock = master->lock.hw_lock; |
3e5fc80a DA |
126 | block_all_signals(drm_notifier, &dev->sigdata, &dev->sigmask); |
127 | } | |
b5e89ed5 | 128 | |
c153f45f EA |
129 | if (dev->driver->dma_quiescent && (lock->flags & _DRM_LOCK_QUIESCENT)) |
130 | { | |
d985c108 | 131 | if (dev->driver->dma_quiescent(dev)) { |
c153f45f EA |
132 | DRM_DEBUG("%d waiting for DMA quiescent\n", |
133 | lock->context); | |
20caafa6 | 134 | return -EBUSY; |
d985c108 DA |
135 | } |
136 | } | |
b5e89ed5 | 137 | |
d985c108 | 138 | return 0; |
1da177e4 LT |
139 | } |
140 | ||
b5e89ed5 | 141 | /** |
1da177e4 LT |
142 | * Unlock ioctl. |
143 | * | |
144 | * \param inode device inode. | |
6c340eac | 145 | * \param file_priv DRM file private. |
1da177e4 LT |
146 | * \param cmd command. |
147 | * \param arg user argument, pointing to a drm_lock structure. | |
148 | * \return zero on success or negative number on failure. | |
149 | * | |
150 | * Transfer and free the lock. | |
151 | */ | |
c153f45f | 152 | int drm_unlock(struct drm_device *dev, void *data, struct drm_file *file_priv) |
1da177e4 | 153 | { |
c153f45f | 154 | struct drm_lock *lock = data; |
1da177e4 | 155 | |
c153f45f | 156 | if (lock->context == DRM_KERNEL_CONTEXT) { |
b5e89ed5 | 157 | DRM_ERROR("Process %d using kernel context %d\n", |
ba25f9dc | 158 | task_pid_nr(current), lock->context); |
1da177e4 LT |
159 | return -EINVAL; |
160 | } | |
161 | ||
b5e89ed5 | 162 | atomic_inc(&dev->counts[_DRM_STAT_UNLOCKS]); |
1da177e4 | 163 | |
1da177e4 LT |
164 | unblock_all_signals(); |
165 | return 0; | |
166 | } | |
167 | ||
168 | /** | |
169 | * Take the heavyweight lock. | |
170 | * | |
171 | * \param lock lock pointer. | |
172 | * \param context locking context. | |
173 | * \return one if the lock is held, or zero otherwise. | |
174 | * | |
175 | * Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction. | |
176 | */ | |
4ac5ec40 | 177 | static |
55910517 | 178 | int drm_lock_take(struct drm_lock_data *lock_data, |
040ac320 | 179 | unsigned int context) |
1da177e4 LT |
180 | { |
181 | unsigned int old, new, prev; | |
040ac320 | 182 | volatile unsigned int *lock = &lock_data->hw_lock->lock; |
1da177e4 | 183 | |
f116cc56 | 184 | spin_lock_bh(&lock_data->spinlock); |
1da177e4 LT |
185 | do { |
186 | old = *lock; | |
b5e89ed5 DA |
187 | if (old & _DRM_LOCK_HELD) |
188 | new = old | _DRM_LOCK_CONT; | |
040ac320 TH |
189 | else { |
190 | new = context | _DRM_LOCK_HELD | | |
191 | ((lock_data->user_waiters + lock_data->kernel_waiters > 1) ? | |
192 | _DRM_LOCK_CONT : 0); | |
193 | } | |
1da177e4 LT |
194 | prev = cmpxchg(lock, old, new); |
195 | } while (prev != old); | |
f116cc56 | 196 | spin_unlock_bh(&lock_data->spinlock); |
040ac320 | 197 | |
1da177e4 LT |
198 | if (_DRM_LOCKING_CONTEXT(old) == context) { |
199 | if (old & _DRM_LOCK_HELD) { | |
200 | if (context != DRM_KERNEL_CONTEXT) { | |
201 | DRM_ERROR("%d holds heavyweight lock\n", | |
202 | context); | |
203 | } | |
204 | return 0; | |
205 | } | |
206 | } | |
040ac320 TH |
207 | |
208 | if ((_DRM_LOCKING_CONTEXT(new)) == context && (new & _DRM_LOCK_HELD)) { | |
b5e89ed5 | 209 | /* Have lock */ |
1da177e4 LT |
210 | return 1; |
211 | } | |
212 | return 0; | |
213 | } | |
214 | ||
215 | /** | |
216 | * This takes a lock forcibly and hands it to context. Should ONLY be used | |
b5e89ed5 DA |
217 | * inside *_unlock to give lock to kernel before calling *_dma_schedule. |
218 | * | |
1da177e4 LT |
219 | * \param dev DRM device. |
220 | * \param lock lock pointer. | |
221 | * \param context locking context. | |
222 | * \return always one. | |
223 | * | |
224 | * Resets the lock file pointer. | |
225 | * Marks the lock as held by the given context, via the \p cmpxchg instruction. | |
226 | */ | |
55910517 | 227 | static int drm_lock_transfer(struct drm_lock_data *lock_data, |
c94f7029 | 228 | unsigned int context) |
1da177e4 LT |
229 | { |
230 | unsigned int old, new, prev; | |
040ac320 | 231 | volatile unsigned int *lock = &lock_data->hw_lock->lock; |
1da177e4 | 232 | |
6c340eac | 233 | lock_data->file_priv = NULL; |
1da177e4 | 234 | do { |
b5e89ed5 DA |
235 | old = *lock; |
236 | new = context | _DRM_LOCK_HELD; | |
1da177e4 LT |
237 | prev = cmpxchg(lock, old, new); |
238 | } while (prev != old); | |
239 | return 1; | |
240 | } | |
241 | ||
242 | /** | |
243 | * Free lock. | |
b5e89ed5 | 244 | * |
1da177e4 LT |
245 | * \param dev DRM device. |
246 | * \param lock lock. | |
247 | * \param context context. | |
b5e89ed5 | 248 | * |
1da177e4 LT |
249 | * Resets the lock file pointer. |
250 | * Marks the lock as not held, via the \p cmpxchg instruction. Wakes any task | |
251 | * waiting on the lock queue. | |
252 | */ | |
55910517 | 253 | int drm_lock_free(struct drm_lock_data *lock_data, unsigned int context) |
1da177e4 LT |
254 | { |
255 | unsigned int old, new, prev; | |
040ac320 TH |
256 | volatile unsigned int *lock = &lock_data->hw_lock->lock; |
257 | ||
f116cc56 | 258 | spin_lock_bh(&lock_data->spinlock); |
040ac320 TH |
259 | if (lock_data->kernel_waiters != 0) { |
260 | drm_lock_transfer(lock_data, 0); | |
261 | lock_data->idle_has_lock = 1; | |
f116cc56 | 262 | spin_unlock_bh(&lock_data->spinlock); |
040ac320 TH |
263 | return 1; |
264 | } | |
f116cc56 | 265 | spin_unlock_bh(&lock_data->spinlock); |
1da177e4 | 266 | |
1da177e4 | 267 | do { |
b5e89ed5 | 268 | old = *lock; |
040ac320 | 269 | new = _DRM_LOCKING_CONTEXT(old); |
1da177e4 LT |
270 | prev = cmpxchg(lock, old, new); |
271 | } while (prev != old); | |
040ac320 | 272 | |
1da177e4 LT |
273 | if (_DRM_LOCK_IS_HELD(old) && _DRM_LOCKING_CONTEXT(old) != context) { |
274 | DRM_ERROR("%d freed heavyweight lock held by %d\n", | |
b5e89ed5 | 275 | context, _DRM_LOCKING_CONTEXT(old)); |
1da177e4 LT |
276 | return 1; |
277 | } | |
040ac320 | 278 | wake_up_interruptible(&lock_data->lock_queue); |
1da177e4 LT |
279 | return 0; |
280 | } | |
281 | ||
282 | /** | |
283 | * If we get here, it means that the process has called DRM_IOCTL_LOCK | |
284 | * without calling DRM_IOCTL_UNLOCK. | |
285 | * | |
286 | * If the lock is not held, then let the signal proceed as usual. If the lock | |
287 | * is held, then set the contended flag and keep the signal blocked. | |
288 | * | |
289 | * \param priv pointer to a drm_sigdata structure. | |
290 | * \return one if the signal should be delivered normally, or zero if the | |
291 | * signal should be blocked. | |
292 | */ | |
c94f7029 | 293 | static int drm_notifier(void *priv) |
1da177e4 | 294 | { |
55910517 | 295 | struct drm_sigdata *s = (struct drm_sigdata *) priv; |
b5e89ed5 | 296 | unsigned int old, new, prev; |
1da177e4 | 297 | |
b5e89ed5 | 298 | /* Allow signal delivery if lock isn't held */ |
1da177e4 | 299 | if (!s->lock || !_DRM_LOCK_IS_HELD(s->lock->lock) |
b5e89ed5 DA |
300 | || _DRM_LOCKING_CONTEXT(s->lock->lock) != s->context) |
301 | return 1; | |
1da177e4 | 302 | |
b5e89ed5 DA |
303 | /* Otherwise, set flag to force call to |
304 | drmUnlock */ | |
1da177e4 | 305 | do { |
b5e89ed5 DA |
306 | old = s->lock->lock; |
307 | new = old | _DRM_LOCK_CONT; | |
1da177e4 LT |
308 | prev = cmpxchg(&s->lock->lock, old, new); |
309 | } while (prev != old); | |
310 | return 0; | |
311 | } | |
040ac320 TH |
312 | |
313 | /** | |
314 | * This function returns immediately and takes the hw lock | |
315 | * with the kernel context if it is free, otherwise it gets the highest priority when and if | |
316 | * it is eventually released. | |
317 | * | |
318 | * This guarantees that the kernel will _eventually_ have the lock _unless_ it is held | |
319 | * by a blocked process. (In the latter case an explicit wait for the hardware lock would cause | |
320 | * a deadlock, which is why the "idlelock" was invented). | |
321 | * | |
322 | * This should be sufficient to wait for GPU idle without | |
323 | * having to worry about starvation. | |
324 | */ | |
325 | ||
55910517 | 326 | void drm_idlelock_take(struct drm_lock_data *lock_data) |
040ac320 TH |
327 | { |
328 | int ret = 0; | |
329 | ||
f116cc56 | 330 | spin_lock_bh(&lock_data->spinlock); |
040ac320 TH |
331 | lock_data->kernel_waiters++; |
332 | if (!lock_data->idle_has_lock) { | |
333 | ||
f116cc56 | 334 | spin_unlock_bh(&lock_data->spinlock); |
040ac320 | 335 | ret = drm_lock_take(lock_data, DRM_KERNEL_CONTEXT); |
f116cc56 | 336 | spin_lock_bh(&lock_data->spinlock); |
040ac320 TH |
337 | |
338 | if (ret == 1) | |
339 | lock_data->idle_has_lock = 1; | |
340 | } | |
f116cc56 | 341 | spin_unlock_bh(&lock_data->spinlock); |
040ac320 | 342 | } |
040ac320 | 343 | |
55910517 | 344 | void drm_idlelock_release(struct drm_lock_data *lock_data) |
040ac320 TH |
345 | { |
346 | unsigned int old, prev; | |
347 | volatile unsigned int *lock = &lock_data->hw_lock->lock; | |
348 | ||
f116cc56 | 349 | spin_lock_bh(&lock_data->spinlock); |
040ac320 TH |
350 | if (--lock_data->kernel_waiters == 0) { |
351 | if (lock_data->idle_has_lock) { | |
352 | do { | |
353 | old = *lock; | |
354 | prev = cmpxchg(lock, old, DRM_KERNEL_CONTEXT); | |
355 | } while (prev != old); | |
356 | wake_up_interruptible(&lock_data->lock_queue); | |
357 | lock_data->idle_has_lock = 0; | |
358 | } | |
359 | } | |
f116cc56 | 360 | spin_unlock_bh(&lock_data->spinlock); |
040ac320 | 361 | } |
040ac320 | 362 | |
c153f45f | 363 | int drm_i_have_hw_lock(struct drm_device *dev, struct drm_file *file_priv) |
040ac320 | 364 | { |
7c1c2871 DA |
365 | struct drm_master *master = file_priv->master; |
366 | return (file_priv->lock_count && master->lock.hw_lock && | |
367 | _DRM_LOCK_IS_HELD(master->lock.hw_lock->lock) && | |
368 | master->lock.file_priv == file_priv); | |
040ac320 | 369 | } |