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> |
e7b96070 | 38 | #include "drm_legacy.h" |
44af3f5c | 39 | #include "drm_internal.h" |
1da177e4 | 40 | |
c94f7029 DA |
41 | static int drm_notifier(void *priv); |
42 | ||
4ac5ec40 DV |
43 | static int drm_lock_take(struct drm_lock_data *lock_data, unsigned int context); |
44 | ||
b5e89ed5 | 45 | /** |
1da177e4 LT |
46 | * Lock ioctl. |
47 | * | |
48 | * \param inode device inode. | |
6c340eac | 49 | * \param file_priv DRM file private. |
1da177e4 LT |
50 | * \param cmd command. |
51 | * \param arg user argument, pointing to a drm_lock structure. | |
52 | * \return zero on success or negative number on failure. | |
53 | * | |
54 | * Add the current task to the lock wait queue, and attempt to take to lock. | |
55 | */ | |
bb6d822e DH |
56 | int drm_legacy_lock(struct drm_device *dev, void *data, |
57 | struct drm_file *file_priv) | |
1da177e4 | 58 | { |
b5e89ed5 | 59 | DECLARE_WAITQUEUE(entry, current); |
c153f45f | 60 | struct drm_lock *lock = data; |
7c1c2871 | 61 | struct drm_master *master = file_priv->master; |
b5e89ed5 | 62 | int ret = 0; |
1da177e4 | 63 | |
da168d81 DV |
64 | if (drm_core_check_feature(dev, DRIVER_MODESET)) |
65 | return -EINVAL; | |
66 | ||
6c340eac | 67 | ++file_priv->lock_count; |
1da177e4 | 68 | |
c153f45f | 69 | if (lock->context == DRM_KERNEL_CONTEXT) { |
b5e89ed5 | 70 | DRM_ERROR("Process %d using kernel context %d\n", |
ba25f9dc | 71 | task_pid_nr(current), lock->context); |
b5e89ed5 DA |
72 | return -EINVAL; |
73 | } | |
1da177e4 | 74 | |
b5e89ed5 | 75 | DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n", |
ba25f9dc | 76 | lock->context, task_pid_nr(current), |
7c1c2871 | 77 | master->lock.hw_lock->lock, lock->flags); |
1da177e4 | 78 | |
7c1c2871 DA |
79 | add_wait_queue(&master->lock.lock_queue, &entry); |
80 | spin_lock_bh(&master->lock.spinlock); | |
81 | master->lock.user_waiters++; | |
82 | spin_unlock_bh(&master->lock.spinlock); | |
83 | ||
1da177e4 LT |
84 | for (;;) { |
85 | __set_current_state(TASK_INTERRUPTIBLE); | |
7c1c2871 | 86 | if (!master->lock.hw_lock) { |
1da177e4 | 87 | /* Device has been unregistered */ |
fda714c2 | 88 | send_sig(SIGTERM, current, 0); |
1da177e4 LT |
89 | ret = -EINTR; |
90 | break; | |
91 | } | |
7c1c2871 DA |
92 | if (drm_lock_take(&master->lock, lock->context)) { |
93 | master->lock.file_priv = file_priv; | |
94 | master->lock.lock_time = jiffies; | |
b5e89ed5 | 95 | break; /* Got lock */ |
1da177e4 | 96 | } |
b5e89ed5 | 97 | |
1da177e4 | 98 | /* Contention */ |
08f2e669 | 99 | mutex_unlock(&drm_global_mutex); |
1da177e4 | 100 | schedule(); |
08f2e669 | 101 | mutex_lock(&drm_global_mutex); |
b5e89ed5 | 102 | if (signal_pending(current)) { |
4d77c88e | 103 | ret = -EINTR; |
1da177e4 LT |
104 | break; |
105 | } | |
106 | } | |
7c1c2871 DA |
107 | spin_lock_bh(&master->lock.spinlock); |
108 | master->lock.user_waiters--; | |
109 | spin_unlock_bh(&master->lock.spinlock); | |
1da177e4 | 110 | __set_current_state(TASK_RUNNING); |
7c1c2871 | 111 | remove_wait_queue(&master->lock.lock_queue, &entry); |
1da177e4 | 112 | |
c153f45f EA |
113 | DRM_DEBUG("%d %s\n", lock->context, |
114 | ret ? "interrupted" : "has lock"); | |
040ac320 | 115 | if (ret) return ret; |
d985c108 | 116 | |
3e5fc80a DA |
117 | /* don't set the block all signals on the master process for now |
118 | * really probably not the correct answer but lets us debug xkb | |
119 | * xserver for now */ | |
7963e9db | 120 | if (!file_priv->is_master) { |
3e5fc80a DA |
121 | sigemptyset(&dev->sigmask); |
122 | sigaddset(&dev->sigmask, SIGSTOP); | |
123 | sigaddset(&dev->sigmask, SIGTSTP); | |
124 | sigaddset(&dev->sigmask, SIGTTIN); | |
125 | sigaddset(&dev->sigmask, SIGTTOU); | |
126 | dev->sigdata.context = lock->context; | |
7c1c2871 | 127 | dev->sigdata.lock = master->lock.hw_lock; |
69d516c0 | 128 | block_all_signals(drm_notifier, dev, &dev->sigmask); |
3e5fc80a | 129 | } |
b5e89ed5 | 130 | |
c153f45f EA |
131 | if (dev->driver->dma_quiescent && (lock->flags & _DRM_LOCK_QUIESCENT)) |
132 | { | |
d985c108 | 133 | if (dev->driver->dma_quiescent(dev)) { |
c153f45f EA |
134 | DRM_DEBUG("%d waiting for DMA quiescent\n", |
135 | lock->context); | |
20caafa6 | 136 | return -EBUSY; |
d985c108 DA |
137 | } |
138 | } | |
b5e89ed5 | 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 | */ | |
bb6d822e | 154 | int drm_legacy_unlock(struct drm_device *dev, void *data, struct drm_file *file_priv) |
1da177e4 | 155 | { |
c153f45f | 156 | struct drm_lock *lock = data; |
45ff46c5 | 157 | struct drm_master *master = file_priv->master; |
1da177e4 | 158 | |
da168d81 DV |
159 | if (drm_core_check_feature(dev, DRIVER_MODESET)) |
160 | return -EINVAL; | |
161 | ||
c153f45f | 162 | if (lock->context == DRM_KERNEL_CONTEXT) { |
b5e89ed5 | 163 | DRM_ERROR("Process %d using kernel context %d\n", |
ba25f9dc | 164 | task_pid_nr(current), lock->context); |
1da177e4 LT |
165 | return -EINVAL; |
166 | } | |
167 | ||
bb6d822e | 168 | if (drm_legacy_lock_free(&master->lock, lock->context)) { |
45ff46c5 DV |
169 | /* FIXME: Should really bail out here. */ |
170 | } | |
171 | ||
1da177e4 LT |
172 | unblock_all_signals(); |
173 | return 0; | |
174 | } | |
175 | ||
176 | /** | |
177 | * Take the heavyweight lock. | |
178 | * | |
179 | * \param lock lock pointer. | |
180 | * \param context locking context. | |
181 | * \return one if the lock is held, or zero otherwise. | |
182 | * | |
183 | * Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction. | |
184 | */ | |
4ac5ec40 | 185 | static |
55910517 | 186 | int drm_lock_take(struct drm_lock_data *lock_data, |
040ac320 | 187 | unsigned int context) |
1da177e4 LT |
188 | { |
189 | unsigned int old, new, prev; | |
040ac320 | 190 | volatile unsigned int *lock = &lock_data->hw_lock->lock; |
1da177e4 | 191 | |
f116cc56 | 192 | spin_lock_bh(&lock_data->spinlock); |
1da177e4 LT |
193 | do { |
194 | old = *lock; | |
b5e89ed5 DA |
195 | if (old & _DRM_LOCK_HELD) |
196 | new = old | _DRM_LOCK_CONT; | |
040ac320 TH |
197 | else { |
198 | new = context | _DRM_LOCK_HELD | | |
199 | ((lock_data->user_waiters + lock_data->kernel_waiters > 1) ? | |
200 | _DRM_LOCK_CONT : 0); | |
201 | } | |
1da177e4 LT |
202 | prev = cmpxchg(lock, old, new); |
203 | } while (prev != old); | |
f116cc56 | 204 | spin_unlock_bh(&lock_data->spinlock); |
040ac320 | 205 | |
1da177e4 LT |
206 | if (_DRM_LOCKING_CONTEXT(old) == context) { |
207 | if (old & _DRM_LOCK_HELD) { | |
208 | if (context != DRM_KERNEL_CONTEXT) { | |
209 | DRM_ERROR("%d holds heavyweight lock\n", | |
210 | context); | |
211 | } | |
212 | return 0; | |
213 | } | |
214 | } | |
040ac320 TH |
215 | |
216 | if ((_DRM_LOCKING_CONTEXT(new)) == context && (new & _DRM_LOCK_HELD)) { | |
b5e89ed5 | 217 | /* Have lock */ |
1da177e4 LT |
218 | return 1; |
219 | } | |
220 | return 0; | |
221 | } | |
222 | ||
223 | /** | |
224 | * This takes a lock forcibly and hands it to context. Should ONLY be used | |
b5e89ed5 DA |
225 | * inside *_unlock to give lock to kernel before calling *_dma_schedule. |
226 | * | |
1da177e4 LT |
227 | * \param dev DRM device. |
228 | * \param lock lock pointer. | |
229 | * \param context locking context. | |
230 | * \return always one. | |
231 | * | |
232 | * Resets the lock file pointer. | |
233 | * Marks the lock as held by the given context, via the \p cmpxchg instruction. | |
234 | */ | |
55910517 | 235 | static int drm_lock_transfer(struct drm_lock_data *lock_data, |
c94f7029 | 236 | unsigned int context) |
1da177e4 LT |
237 | { |
238 | unsigned int old, new, prev; | |
040ac320 | 239 | volatile unsigned int *lock = &lock_data->hw_lock->lock; |
1da177e4 | 240 | |
6c340eac | 241 | lock_data->file_priv = NULL; |
1da177e4 | 242 | do { |
b5e89ed5 DA |
243 | old = *lock; |
244 | new = context | _DRM_LOCK_HELD; | |
1da177e4 LT |
245 | prev = cmpxchg(lock, old, new); |
246 | } while (prev != old); | |
247 | return 1; | |
248 | } | |
249 | ||
250 | /** | |
251 | * Free lock. | |
b5e89ed5 | 252 | * |
1da177e4 LT |
253 | * \param dev DRM device. |
254 | * \param lock lock. | |
255 | * \param context context. | |
b5e89ed5 | 256 | * |
1da177e4 LT |
257 | * Resets the lock file pointer. |
258 | * Marks the lock as not held, via the \p cmpxchg instruction. Wakes any task | |
259 | * waiting on the lock queue. | |
260 | */ | |
bb6d822e | 261 | int drm_legacy_lock_free(struct drm_lock_data *lock_data, unsigned int context) |
1da177e4 LT |
262 | { |
263 | unsigned int old, new, prev; | |
040ac320 TH |
264 | volatile unsigned int *lock = &lock_data->hw_lock->lock; |
265 | ||
f116cc56 | 266 | spin_lock_bh(&lock_data->spinlock); |
040ac320 TH |
267 | if (lock_data->kernel_waiters != 0) { |
268 | drm_lock_transfer(lock_data, 0); | |
269 | lock_data->idle_has_lock = 1; | |
f116cc56 | 270 | spin_unlock_bh(&lock_data->spinlock); |
040ac320 TH |
271 | return 1; |
272 | } | |
f116cc56 | 273 | spin_unlock_bh(&lock_data->spinlock); |
1da177e4 | 274 | |
1da177e4 | 275 | do { |
b5e89ed5 | 276 | old = *lock; |
040ac320 | 277 | new = _DRM_LOCKING_CONTEXT(old); |
1da177e4 LT |
278 | prev = cmpxchg(lock, old, new); |
279 | } while (prev != old); | |
040ac320 | 280 | |
1da177e4 LT |
281 | if (_DRM_LOCK_IS_HELD(old) && _DRM_LOCKING_CONTEXT(old) != context) { |
282 | DRM_ERROR("%d freed heavyweight lock held by %d\n", | |
b5e89ed5 | 283 | context, _DRM_LOCKING_CONTEXT(old)); |
1da177e4 LT |
284 | return 1; |
285 | } | |
040ac320 | 286 | wake_up_interruptible(&lock_data->lock_queue); |
1da177e4 LT |
287 | return 0; |
288 | } | |
289 | ||
290 | /** | |
291 | * If we get here, it means that the process has called DRM_IOCTL_LOCK | |
292 | * without calling DRM_IOCTL_UNLOCK. | |
293 | * | |
294 | * If the lock is not held, then let the signal proceed as usual. If the lock | |
295 | * is held, then set the contended flag and keep the signal blocked. | |
296 | * | |
69d516c0 | 297 | * \param priv pointer to a drm_device structure. |
1da177e4 LT |
298 | * \return one if the signal should be delivered normally, or zero if the |
299 | * signal should be blocked. | |
300 | */ | |
c94f7029 | 301 | static int drm_notifier(void *priv) |
1da177e4 | 302 | { |
69d516c0 DH |
303 | struct drm_device *dev = priv; |
304 | struct drm_hw_lock *lock = dev->sigdata.lock; | |
b5e89ed5 | 305 | unsigned int old, new, prev; |
1da177e4 | 306 | |
b5e89ed5 | 307 | /* Allow signal delivery if lock isn't held */ |
69d516c0 DH |
308 | if (!lock || !_DRM_LOCK_IS_HELD(lock->lock) |
309 | || _DRM_LOCKING_CONTEXT(lock->lock) != dev->sigdata.context) | |
b5e89ed5 | 310 | return 1; |
1da177e4 | 311 | |
b5e89ed5 DA |
312 | /* Otherwise, set flag to force call to |
313 | drmUnlock */ | |
1da177e4 | 314 | do { |
69d516c0 | 315 | old = lock->lock; |
b5e89ed5 | 316 | new = old | _DRM_LOCK_CONT; |
69d516c0 | 317 | prev = cmpxchg(&lock->lock, old, new); |
1da177e4 LT |
318 | } while (prev != old); |
319 | return 0; | |
320 | } | |
040ac320 TH |
321 | |
322 | /** | |
323 | * This function returns immediately and takes the hw lock | |
324 | * with the kernel context if it is free, otherwise it gets the highest priority when and if | |
325 | * it is eventually released. | |
326 | * | |
327 | * This guarantees that the kernel will _eventually_ have the lock _unless_ it is held | |
328 | * by a blocked process. (In the latter case an explicit wait for the hardware lock would cause | |
329 | * a deadlock, which is why the "idlelock" was invented). | |
330 | * | |
331 | * This should be sufficient to wait for GPU idle without | |
332 | * having to worry about starvation. | |
333 | */ | |
334 | ||
bb6d822e | 335 | void drm_legacy_idlelock_take(struct drm_lock_data *lock_data) |
040ac320 | 336 | { |
4a1b0714 | 337 | int ret; |
040ac320 | 338 | |
f116cc56 | 339 | spin_lock_bh(&lock_data->spinlock); |
040ac320 TH |
340 | lock_data->kernel_waiters++; |
341 | if (!lock_data->idle_has_lock) { | |
342 | ||
f116cc56 | 343 | spin_unlock_bh(&lock_data->spinlock); |
040ac320 | 344 | ret = drm_lock_take(lock_data, DRM_KERNEL_CONTEXT); |
f116cc56 | 345 | spin_lock_bh(&lock_data->spinlock); |
040ac320 TH |
346 | |
347 | if (ret == 1) | |
348 | lock_data->idle_has_lock = 1; | |
349 | } | |
f116cc56 | 350 | spin_unlock_bh(&lock_data->spinlock); |
040ac320 | 351 | } |
bb6d822e | 352 | EXPORT_SYMBOL(drm_legacy_idlelock_take); |
040ac320 | 353 | |
bb6d822e | 354 | void drm_legacy_idlelock_release(struct drm_lock_data *lock_data) |
040ac320 TH |
355 | { |
356 | unsigned int old, prev; | |
357 | volatile unsigned int *lock = &lock_data->hw_lock->lock; | |
358 | ||
f116cc56 | 359 | spin_lock_bh(&lock_data->spinlock); |
040ac320 TH |
360 | if (--lock_data->kernel_waiters == 0) { |
361 | if (lock_data->idle_has_lock) { | |
362 | do { | |
363 | old = *lock; | |
364 | prev = cmpxchg(lock, old, DRM_KERNEL_CONTEXT); | |
365 | } while (prev != old); | |
366 | wake_up_interruptible(&lock_data->lock_queue); | |
367 | lock_data->idle_has_lock = 0; | |
368 | } | |
369 | } | |
f116cc56 | 370 | spin_unlock_bh(&lock_data->spinlock); |
040ac320 | 371 | } |
bb6d822e | 372 | EXPORT_SYMBOL(drm_legacy_idlelock_release); |
040ac320 | 373 | |
bb6d822e DH |
374 | int drm_legacy_i_have_hw_lock(struct drm_device *dev, |
375 | struct drm_file *file_priv) | |
040ac320 | 376 | { |
7c1c2871 DA |
377 | struct drm_master *master = file_priv->master; |
378 | return (file_priv->lock_count && master->lock.hw_lock && | |
379 | _DRM_LOCK_IS_HELD(master->lock.hw_lock->lock) && | |
380 | master->lock.file_priv == file_priv); | |
040ac320 | 381 | } |