Commit | Line | Data |
---|---|---|
45b2fda3 | 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> |
3f07c014 IM |
37 | #include <linux/sched/signal.h> |
38 | ||
0500c04e SR |
39 | #include <drm/drm.h> |
40 | #include <drm/drm_drv.h> | |
41 | #include <drm/drm_file.h> | |
42 | #include <drm/drm_print.h> | |
43 | ||
44af3f5c | 44 | #include "drm_internal.h" |
0500c04e | 45 | #include "drm_legacy.h" |
1da177e4 | 46 | |
4ac5ec40 DV |
47 | static int drm_lock_take(struct drm_lock_data *lock_data, unsigned int context); |
48 | ||
1a75a222 DV |
49 | /** |
50 | * Take the heavyweight lock. | |
51 | * | |
52 | * \param lock lock pointer. | |
53 | * \param context locking context. | |
54 | * \return one if the lock is held, or zero otherwise. | |
55 | * | |
56 | * Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction. | |
57 | */ | |
58 | static | |
59 | int drm_lock_take(struct drm_lock_data *lock_data, | |
60 | unsigned int context) | |
61 | { | |
62 | unsigned int old, new, prev; | |
63 | volatile unsigned int *lock = &lock_data->hw_lock->lock; | |
64 | ||
65 | spin_lock_bh(&lock_data->spinlock); | |
66 | do { | |
67 | old = *lock; | |
68 | if (old & _DRM_LOCK_HELD) | |
69 | new = old | _DRM_LOCK_CONT; | |
70 | else { | |
71 | new = context | _DRM_LOCK_HELD | | |
72 | ((lock_data->user_waiters + lock_data->kernel_waiters > 1) ? | |
73 | _DRM_LOCK_CONT : 0); | |
74 | } | |
75 | prev = cmpxchg(lock, old, new); | |
76 | } while (prev != old); | |
77 | spin_unlock_bh(&lock_data->spinlock); | |
78 | ||
79 | if (_DRM_LOCKING_CONTEXT(old) == context) { | |
80 | if (old & _DRM_LOCK_HELD) { | |
81 | if (context != DRM_KERNEL_CONTEXT) { | |
82 | DRM_ERROR("%d holds heavyweight lock\n", | |
83 | context); | |
84 | } | |
85 | return 0; | |
86 | } | |
87 | } | |
88 | ||
89 | if ((_DRM_LOCKING_CONTEXT(new)) == context && (new & _DRM_LOCK_HELD)) { | |
90 | /* Have lock */ | |
91 | return 1; | |
92 | } | |
93 | return 0; | |
94 | } | |
95 | ||
96 | /** | |
97 | * This takes a lock forcibly and hands it to context. Should ONLY be used | |
98 | * inside *_unlock to give lock to kernel before calling *_dma_schedule. | |
99 | * | |
100 | * \param dev DRM device. | |
101 | * \param lock lock pointer. | |
102 | * \param context locking context. | |
103 | * \return always one. | |
104 | * | |
105 | * Resets the lock file pointer. | |
106 | * Marks the lock as held by the given context, via the \p cmpxchg instruction. | |
107 | */ | |
108 | static int drm_lock_transfer(struct drm_lock_data *lock_data, | |
109 | unsigned int context) | |
110 | { | |
111 | unsigned int old, new, prev; | |
112 | volatile unsigned int *lock = &lock_data->hw_lock->lock; | |
113 | ||
114 | lock_data->file_priv = NULL; | |
115 | do { | |
116 | old = *lock; | |
117 | new = context | _DRM_LOCK_HELD; | |
118 | prev = cmpxchg(lock, old, new); | |
119 | } while (prev != old); | |
120 | return 1; | |
121 | } | |
122 | ||
123 | static int drm_legacy_lock_free(struct drm_lock_data *lock_data, | |
124 | unsigned int context) | |
125 | { | |
126 | unsigned int old, new, prev; | |
127 | volatile unsigned int *lock = &lock_data->hw_lock->lock; | |
128 | ||
129 | spin_lock_bh(&lock_data->spinlock); | |
130 | if (lock_data->kernel_waiters != 0) { | |
131 | drm_lock_transfer(lock_data, 0); | |
132 | lock_data->idle_has_lock = 1; | |
133 | spin_unlock_bh(&lock_data->spinlock); | |
134 | return 1; | |
135 | } | |
136 | spin_unlock_bh(&lock_data->spinlock); | |
137 | ||
138 | do { | |
139 | old = *lock; | |
140 | new = _DRM_LOCKING_CONTEXT(old); | |
141 | prev = cmpxchg(lock, old, new); | |
142 | } while (prev != old); | |
143 | ||
144 | if (_DRM_LOCK_IS_HELD(old) && _DRM_LOCKING_CONTEXT(old) != context) { | |
145 | DRM_ERROR("%d freed heavyweight lock held by %d\n", | |
146 | context, _DRM_LOCKING_CONTEXT(old)); | |
147 | return 1; | |
148 | } | |
149 | wake_up_interruptible(&lock_data->lock_queue); | |
150 | return 0; | |
151 | } | |
152 | ||
b5e89ed5 | 153 | /** |
1da177e4 LT |
154 | * Lock ioctl. |
155 | * | |
156 | * \param inode device inode. | |
6c340eac | 157 | * \param file_priv DRM file private. |
1da177e4 LT |
158 | * \param cmd command. |
159 | * \param arg user argument, pointing to a drm_lock structure. | |
160 | * \return zero on success or negative number on failure. | |
161 | * | |
162 | * Add the current task to the lock wait queue, and attempt to take to lock. | |
163 | */ | |
bb6d822e DH |
164 | int drm_legacy_lock(struct drm_device *dev, void *data, |
165 | struct drm_file *file_priv) | |
1da177e4 | 166 | { |
b5e89ed5 | 167 | DECLARE_WAITQUEUE(entry, current); |
c153f45f | 168 | struct drm_lock *lock = data; |
7c1c2871 | 169 | struct drm_master *master = file_priv->master; |
b5e89ed5 | 170 | int ret = 0; |
1da177e4 | 171 | |
fa538645 | 172 | if (!drm_core_check_feature(dev, DRIVER_LEGACY)) |
69fdf420 | 173 | return -EOPNOTSUPP; |
da168d81 | 174 | |
6c340eac | 175 | ++file_priv->lock_count; |
1da177e4 | 176 | |
c153f45f | 177 | if (lock->context == DRM_KERNEL_CONTEXT) { |
b5e89ed5 | 178 | DRM_ERROR("Process %d using kernel context %d\n", |
ba25f9dc | 179 | task_pid_nr(current), lock->context); |
b5e89ed5 DA |
180 | return -EINVAL; |
181 | } | |
1da177e4 | 182 | |
b5e89ed5 | 183 | DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n", |
ba25f9dc | 184 | lock->context, task_pid_nr(current), |
a2ec1c13 CW |
185 | master->lock.hw_lock ? master->lock.hw_lock->lock : -1, |
186 | lock->flags); | |
1da177e4 | 187 | |
7c1c2871 DA |
188 | add_wait_queue(&master->lock.lock_queue, &entry); |
189 | spin_lock_bh(&master->lock.spinlock); | |
190 | master->lock.user_waiters++; | |
191 | spin_unlock_bh(&master->lock.spinlock); | |
192 | ||
1da177e4 LT |
193 | for (;;) { |
194 | __set_current_state(TASK_INTERRUPTIBLE); | |
7c1c2871 | 195 | if (!master->lock.hw_lock) { |
1da177e4 | 196 | /* Device has been unregistered */ |
fda714c2 | 197 | send_sig(SIGTERM, current, 0); |
1da177e4 LT |
198 | ret = -EINTR; |
199 | break; | |
200 | } | |
7c1c2871 DA |
201 | if (drm_lock_take(&master->lock, lock->context)) { |
202 | master->lock.file_priv = file_priv; | |
203 | master->lock.lock_time = jiffies; | |
b5e89ed5 | 204 | break; /* Got lock */ |
1da177e4 | 205 | } |
b5e89ed5 | 206 | |
1da177e4 | 207 | /* Contention */ |
08f2e669 | 208 | mutex_unlock(&drm_global_mutex); |
1da177e4 | 209 | schedule(); |
08f2e669 | 210 | mutex_lock(&drm_global_mutex); |
b5e89ed5 | 211 | if (signal_pending(current)) { |
4d77c88e | 212 | ret = -EINTR; |
1da177e4 LT |
213 | break; |
214 | } | |
215 | } | |
7c1c2871 DA |
216 | spin_lock_bh(&master->lock.spinlock); |
217 | master->lock.user_waiters--; | |
218 | spin_unlock_bh(&master->lock.spinlock); | |
1da177e4 | 219 | __set_current_state(TASK_RUNNING); |
7c1c2871 | 220 | remove_wait_queue(&master->lock.lock_queue, &entry); |
1da177e4 | 221 | |
c153f45f EA |
222 | DRM_DEBUG("%d %s\n", lock->context, |
223 | ret ? "interrupted" : "has lock"); | |
040ac320 | 224 | if (ret) return ret; |
d985c108 | 225 | |
3e5fc80a DA |
226 | /* don't set the block all signals on the master process for now |
227 | * really probably not the correct answer but lets us debug xkb | |
228 | * xserver for now */ | |
b3ac9f25 | 229 | if (!drm_is_current_master(file_priv)) { |
3e5fc80a | 230 | dev->sigdata.context = lock->context; |
7c1c2871 | 231 | dev->sigdata.lock = master->lock.hw_lock; |
3e5fc80a | 232 | } |
b5e89ed5 | 233 | |
c153f45f EA |
234 | if (dev->driver->dma_quiescent && (lock->flags & _DRM_LOCK_QUIESCENT)) |
235 | { | |
d985c108 | 236 | if (dev->driver->dma_quiescent(dev)) { |
c153f45f EA |
237 | DRM_DEBUG("%d waiting for DMA quiescent\n", |
238 | lock->context); | |
20caafa6 | 239 | return -EBUSY; |
d985c108 DA |
240 | } |
241 | } | |
b5e89ed5 | 242 | |
d985c108 | 243 | return 0; |
1da177e4 LT |
244 | } |
245 | ||
b5e89ed5 | 246 | /** |
1da177e4 LT |
247 | * Unlock ioctl. |
248 | * | |
249 | * \param inode device inode. | |
6c340eac | 250 | * \param file_priv DRM file private. |
1da177e4 LT |
251 | * \param cmd command. |
252 | * \param arg user argument, pointing to a drm_lock structure. | |
253 | * \return zero on success or negative number on failure. | |
254 | * | |
255 | * Transfer and free the lock. | |
256 | */ | |
bb6d822e | 257 | int drm_legacy_unlock(struct drm_device *dev, void *data, struct drm_file *file_priv) |
1da177e4 | 258 | { |
c153f45f | 259 | struct drm_lock *lock = data; |
45ff46c5 | 260 | struct drm_master *master = file_priv->master; |
1da177e4 | 261 | |
fa538645 | 262 | if (!drm_core_check_feature(dev, DRIVER_LEGACY)) |
69fdf420 | 263 | return -EOPNOTSUPP; |
da168d81 | 264 | |
c153f45f | 265 | if (lock->context == DRM_KERNEL_CONTEXT) { |
b5e89ed5 | 266 | DRM_ERROR("Process %d using kernel context %d\n", |
ba25f9dc | 267 | task_pid_nr(current), lock->context); |
1da177e4 LT |
268 | return -EINVAL; |
269 | } | |
270 | ||
bb6d822e | 271 | if (drm_legacy_lock_free(&master->lock, lock->context)) { |
45ff46c5 DV |
272 | /* FIXME: Should really bail out here. */ |
273 | } | |
274 | ||
1da177e4 LT |
275 | return 0; |
276 | } | |
277 | ||
040ac320 TH |
278 | /** |
279 | * This function returns immediately and takes the hw lock | |
280 | * with the kernel context if it is free, otherwise it gets the highest priority when and if | |
281 | * it is eventually released. | |
282 | * | |
283 | * This guarantees that the kernel will _eventually_ have the lock _unless_ it is held | |
284 | * by a blocked process. (In the latter case an explicit wait for the hardware lock would cause | |
285 | * a deadlock, which is why the "idlelock" was invented). | |
286 | * | |
287 | * This should be sufficient to wait for GPU idle without | |
288 | * having to worry about starvation. | |
289 | */ | |
290 | ||
bb6d822e | 291 | void drm_legacy_idlelock_take(struct drm_lock_data *lock_data) |
040ac320 | 292 | { |
4a1b0714 | 293 | int ret; |
040ac320 | 294 | |
f116cc56 | 295 | spin_lock_bh(&lock_data->spinlock); |
040ac320 TH |
296 | lock_data->kernel_waiters++; |
297 | if (!lock_data->idle_has_lock) { | |
298 | ||
f116cc56 | 299 | spin_unlock_bh(&lock_data->spinlock); |
040ac320 | 300 | ret = drm_lock_take(lock_data, DRM_KERNEL_CONTEXT); |
f116cc56 | 301 | spin_lock_bh(&lock_data->spinlock); |
040ac320 TH |
302 | |
303 | if (ret == 1) | |
304 | lock_data->idle_has_lock = 1; | |
305 | } | |
f116cc56 | 306 | spin_unlock_bh(&lock_data->spinlock); |
040ac320 | 307 | } |
bb6d822e | 308 | EXPORT_SYMBOL(drm_legacy_idlelock_take); |
040ac320 | 309 | |
bb6d822e | 310 | void drm_legacy_idlelock_release(struct drm_lock_data *lock_data) |
040ac320 TH |
311 | { |
312 | unsigned int old, prev; | |
313 | volatile unsigned int *lock = &lock_data->hw_lock->lock; | |
314 | ||
f116cc56 | 315 | spin_lock_bh(&lock_data->spinlock); |
040ac320 TH |
316 | if (--lock_data->kernel_waiters == 0) { |
317 | if (lock_data->idle_has_lock) { | |
318 | do { | |
319 | old = *lock; | |
320 | prev = cmpxchg(lock, old, DRM_KERNEL_CONTEXT); | |
321 | } while (prev != old); | |
322 | wake_up_interruptible(&lock_data->lock_queue); | |
323 | lock_data->idle_has_lock = 0; | |
324 | } | |
325 | } | |
f116cc56 | 326 | spin_unlock_bh(&lock_data->spinlock); |
040ac320 | 327 | } |
bb6d822e | 328 | EXPORT_SYMBOL(drm_legacy_idlelock_release); |
040ac320 | 329 | |
1a75a222 DV |
330 | static int drm_legacy_i_have_hw_lock(struct drm_device *dev, |
331 | struct drm_file *file_priv) | |
040ac320 | 332 | { |
7c1c2871 DA |
333 | struct drm_master *master = file_priv->master; |
334 | return (file_priv->lock_count && master->lock.hw_lock && | |
335 | _DRM_LOCK_IS_HELD(master->lock.hw_lock->lock) && | |
336 | master->lock.file_priv == file_priv); | |
040ac320 | 337 | } |
1a75a222 DV |
338 | |
339 | void drm_legacy_lock_release(struct drm_device *dev, struct file *filp) | |
340 | { | |
341 | struct drm_file *file_priv = filp->private_data; | |
342 | ||
343 | /* if the master has gone away we can't do anything with the lock */ | |
95c081c1 | 344 | if (!dev->master) |
1a75a222 DV |
345 | return; |
346 | ||
347 | if (drm_legacy_i_have_hw_lock(dev, file_priv)) { | |
348 | DRM_DEBUG("File %p released, freeing lock for context %d\n", | |
349 | filp, _DRM_LOCKING_CONTEXT(file_priv->master->lock.hw_lock->lock)); | |
350 | drm_legacy_lock_free(&file_priv->master->lock, | |
351 | _DRM_LOCKING_CONTEXT(file_priv->master->lock.hw_lock->lock)); | |
352 | } | |
353 | } | |
058ca50c DA |
354 | |
355 | void drm_legacy_lock_master_cleanup(struct drm_device *dev, struct drm_master *master) | |
356 | { | |
357 | if (!drm_core_check_feature(dev, DRIVER_LEGACY)) | |
358 | return; | |
359 | ||
360 | /* | |
361 | * Since the master is disappearing, so is the | |
362 | * possibility to lock. | |
363 | */ mutex_lock(&dev->struct_mutex); | |
364 | if (master->lock.hw_lock) { | |
365 | if (dev->sigdata.lock == master->lock.hw_lock) | |
366 | dev->sigdata.lock = NULL; | |
367 | master->lock.hw_lock = NULL; | |
368 | master->lock.file_priv = NULL; | |
369 | wake_up_interruptible_all(&master->lock.lock_queue); | |
370 | } | |
371 | mutex_unlock(&dev->struct_mutex); | |
372 | } |