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 | ||
b5e89ed5 | 38 | static int drm_lock_transfer(drm_device_t * dev, |
c94f7029 DA |
39 | __volatile__ unsigned int *lock, |
40 | unsigned int context); | |
41 | static int drm_notifier(void *priv); | |
42 | ||
b5e89ed5 | 43 | /** |
1da177e4 LT |
44 | * Lock ioctl. |
45 | * | |
46 | * \param inode device inode. | |
47 | * \param filp file pointer. | |
48 | * \param cmd command. | |
49 | * \param arg user argument, pointing to a drm_lock structure. | |
50 | * \return zero on success or negative number on failure. | |
51 | * | |
52 | * Add the current task to the lock wait queue, and attempt to take to lock. | |
53 | */ | |
b5e89ed5 DA |
54 | int drm_lock(struct inode *inode, struct file *filp, |
55 | unsigned int cmd, unsigned long arg) | |
1da177e4 | 56 | { |
b5e89ed5 DA |
57 | drm_file_t *priv = filp->private_data; |
58 | drm_device_t *dev = priv->head->dev; | |
59 | DECLARE_WAITQUEUE(entry, current); | |
60 | drm_lock_t lock; | |
61 | int ret = 0; | |
1da177e4 LT |
62 | |
63 | ++priv->lock_count; | |
64 | ||
b5e89ed5 | 65 | if (copy_from_user(&lock, (drm_lock_t __user *) arg, sizeof(lock))) |
1da177e4 LT |
66 | return -EFAULT; |
67 | ||
b5e89ed5 DA |
68 | if (lock.context == DRM_KERNEL_CONTEXT) { |
69 | DRM_ERROR("Process %d using kernel context %d\n", | |
70 | current->pid, lock.context); | |
71 | return -EINVAL; | |
72 | } | |
1da177e4 | 73 | |
b5e89ed5 DA |
74 | DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n", |
75 | lock.context, current->pid, | |
76 | dev->lock.hw_lock->lock, lock.flags); | |
1da177e4 LT |
77 | |
78 | if (drm_core_check_feature(dev, DRIVER_DMA_QUEUE)) | |
b5e89ed5 | 79 | if (lock.context < 0) |
1da177e4 LT |
80 | return -EINVAL; |
81 | ||
b5e89ed5 | 82 | add_wait_queue(&dev->lock.lock_queue, &entry); |
1da177e4 LT |
83 | for (;;) { |
84 | __set_current_state(TASK_INTERRUPTIBLE); | |
b5e89ed5 | 85 | if (!dev->lock.hw_lock) { |
1da177e4 LT |
86 | /* Device has been unregistered */ |
87 | ret = -EINTR; | |
88 | break; | |
89 | } | |
b5e89ed5 DA |
90 | if (drm_lock_take(&dev->lock.hw_lock->lock, lock.context)) { |
91 | dev->lock.filp = filp; | |
1da177e4 | 92 | dev->lock.lock_time = jiffies; |
b5e89ed5 DA |
93 | atomic_inc(&dev->counts[_DRM_STAT_LOCKS]); |
94 | break; /* Got lock */ | |
1da177e4 | 95 | } |
b5e89ed5 | 96 | |
1da177e4 LT |
97 | /* Contention */ |
98 | schedule(); | |
b5e89ed5 | 99 | if (signal_pending(current)) { |
1da177e4 LT |
100 | ret = -ERESTARTSYS; |
101 | break; | |
102 | } | |
103 | } | |
104 | __set_current_state(TASK_RUNNING); | |
b5e89ed5 | 105 | remove_wait_queue(&dev->lock.lock_queue, &entry); |
1da177e4 | 106 | |
cf65f162 DA |
107 | DRM_DEBUG("%d %s\n", lock.context, ret ? "interrupted" : "has lock"); |
108 | if (ret) | |
109 | return ret; | |
d985c108 | 110 | |
b5e89ed5 DA |
111 | sigemptyset(&dev->sigmask); |
112 | sigaddset(&dev->sigmask, SIGSTOP); | |
113 | sigaddset(&dev->sigmask, SIGTSTP); | |
114 | sigaddset(&dev->sigmask, SIGTTIN); | |
115 | sigaddset(&dev->sigmask, SIGTTOU); | |
1da177e4 | 116 | dev->sigdata.context = lock.context; |
b5e89ed5 DA |
117 | dev->sigdata.lock = dev->lock.hw_lock; |
118 | block_all_signals(drm_notifier, &dev->sigdata, &dev->sigmask); | |
119 | ||
1da177e4 LT |
120 | if (dev->driver->dma_ready && (lock.flags & _DRM_LOCK_READY)) |
121 | dev->driver->dma_ready(dev); | |
b5e89ed5 | 122 | |
d985c108 DA |
123 | if (dev->driver->dma_quiescent && (lock.flags & _DRM_LOCK_QUIESCENT)) { |
124 | if (dev->driver->dma_quiescent(dev)) { | |
cf65f162 | 125 | DRM_DEBUG("%d waiting for DMA quiescent\n", lock.context); |
d985c108 DA |
126 | return DRM_ERR(EBUSY); |
127 | } | |
128 | } | |
b5e89ed5 | 129 | |
b5e89ed5 | 130 | /* dev->driver->kernel_context_switch isn't used by any of the x86 |
1da177e4 LT |
131 | * drivers but is used by the Sparc driver. |
132 | */ | |
b5e89ed5 | 133 | if (dev->driver->kernel_context_switch && |
1da177e4 | 134 | dev->last_context != lock.context) { |
b5e89ed5 DA |
135 | dev->driver->kernel_context_switch(dev, dev->last_context, |
136 | lock.context); | |
1da177e4 | 137 | } |
d985c108 | 138 | return 0; |
1da177e4 LT |
139 | } |
140 | ||
b5e89ed5 | 141 | /** |
1da177e4 LT |
142 | * Unlock ioctl. |
143 | * | |
144 | * \param inode device inode. | |
145 | * \param filp file pointer. | |
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 | */ | |
b5e89ed5 DA |
152 | int drm_unlock(struct inode *inode, struct file *filp, |
153 | unsigned int cmd, unsigned long arg) | |
1da177e4 LT |
154 | { |
155 | drm_file_t *priv = filp->private_data; | |
156 | drm_device_t *dev = priv->head->dev; | |
157 | drm_lock_t lock; | |
2e54a007 | 158 | unsigned int irqflags; |
1da177e4 | 159 | |
b5e89ed5 | 160 | if (copy_from_user(&lock, (drm_lock_t __user *) arg, sizeof(lock))) |
1da177e4 LT |
161 | return -EFAULT; |
162 | ||
b5e89ed5 DA |
163 | if (lock.context == DRM_KERNEL_CONTEXT) { |
164 | DRM_ERROR("Process %d using kernel context %d\n", | |
165 | current->pid, lock.context); | |
1da177e4 LT |
166 | return -EINVAL; |
167 | } | |
168 | ||
2e54a007 MCA |
169 | spin_lock_irqsave(&dev->tasklet_lock, irqflags); |
170 | ||
171 | if (dev->locked_tasklet_func) { | |
172 | dev->locked_tasklet_func(dev); | |
173 | ||
174 | dev->locked_tasklet_func = NULL; | |
175 | } | |
176 | ||
177 | spin_unlock_irqrestore(&dev->tasklet_lock, irqflags); | |
178 | ||
b5e89ed5 | 179 | atomic_inc(&dev->counts[_DRM_STAT_UNLOCKS]); |
1da177e4 LT |
180 | |
181 | /* kernel_context_switch isn't used by any of the x86 drm | |
182 | * modules but is required by the Sparc driver. | |
183 | */ | |
184 | if (dev->driver->kernel_context_switch_unlock) | |
185 | dev->driver->kernel_context_switch_unlock(dev, &lock); | |
186 | else { | |
b5e89ed5 DA |
187 | drm_lock_transfer(dev, &dev->lock.hw_lock->lock, |
188 | DRM_KERNEL_CONTEXT); | |
189 | ||
190 | if (drm_lock_free(dev, &dev->lock.hw_lock->lock, | |
191 | DRM_KERNEL_CONTEXT)) { | |
192 | DRM_ERROR("\n"); | |
1da177e4 LT |
193 | } |
194 | } | |
195 | ||
196 | unblock_all_signals(); | |
197 | return 0; | |
198 | } | |
199 | ||
200 | /** | |
201 | * Take the heavyweight lock. | |
202 | * | |
203 | * \param lock lock pointer. | |
204 | * \param context locking context. | |
205 | * \return one if the lock is held, or zero otherwise. | |
206 | * | |
207 | * Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction. | |
208 | */ | |
209 | int drm_lock_take(__volatile__ unsigned int *lock, unsigned int context) | |
210 | { | |
211 | unsigned int old, new, prev; | |
212 | ||
213 | do { | |
214 | old = *lock; | |
b5e89ed5 DA |
215 | if (old & _DRM_LOCK_HELD) |
216 | new = old | _DRM_LOCK_CONT; | |
217 | else | |
218 | new = context | _DRM_LOCK_HELD; | |
1da177e4 LT |
219 | prev = cmpxchg(lock, old, new); |
220 | } while (prev != old); | |
221 | if (_DRM_LOCKING_CONTEXT(old) == context) { | |
222 | if (old & _DRM_LOCK_HELD) { | |
223 | if (context != DRM_KERNEL_CONTEXT) { | |
224 | DRM_ERROR("%d holds heavyweight lock\n", | |
225 | context); | |
226 | } | |
227 | return 0; | |
228 | } | |
229 | } | |
230 | if (new == (context | _DRM_LOCK_HELD)) { | |
b5e89ed5 | 231 | /* Have lock */ |
1da177e4 LT |
232 | return 1; |
233 | } | |
234 | return 0; | |
235 | } | |
236 | ||
237 | /** | |
238 | * This takes a lock forcibly and hands it to context. Should ONLY be used | |
b5e89ed5 DA |
239 | * inside *_unlock to give lock to kernel before calling *_dma_schedule. |
240 | * | |
1da177e4 LT |
241 | * \param dev DRM device. |
242 | * \param lock lock pointer. | |
243 | * \param context locking context. | |
244 | * \return always one. | |
245 | * | |
246 | * Resets the lock file pointer. | |
247 | * Marks the lock as held by the given context, via the \p cmpxchg instruction. | |
248 | */ | |
b5e89ed5 | 249 | static int drm_lock_transfer(drm_device_t * dev, |
c94f7029 DA |
250 | __volatile__ unsigned int *lock, |
251 | unsigned int context) | |
1da177e4 LT |
252 | { |
253 | unsigned int old, new, prev; | |
254 | ||
255 | dev->lock.filp = NULL; | |
256 | do { | |
b5e89ed5 DA |
257 | old = *lock; |
258 | new = context | _DRM_LOCK_HELD; | |
1da177e4 LT |
259 | prev = cmpxchg(lock, old, new); |
260 | } while (prev != old); | |
261 | return 1; | |
262 | } | |
263 | ||
264 | /** | |
265 | * Free lock. | |
b5e89ed5 | 266 | * |
1da177e4 LT |
267 | * \param dev DRM device. |
268 | * \param lock lock. | |
269 | * \param context context. | |
b5e89ed5 | 270 | * |
1da177e4 LT |
271 | * Resets the lock file pointer. |
272 | * Marks the lock as not held, via the \p cmpxchg instruction. Wakes any task | |
273 | * waiting on the lock queue. | |
274 | */ | |
b5e89ed5 DA |
275 | int drm_lock_free(drm_device_t * dev, |
276 | __volatile__ unsigned int *lock, unsigned int context) | |
1da177e4 LT |
277 | { |
278 | unsigned int old, new, prev; | |
279 | ||
280 | dev->lock.filp = NULL; | |
281 | do { | |
b5e89ed5 DA |
282 | old = *lock; |
283 | new = 0; | |
1da177e4 LT |
284 | prev = cmpxchg(lock, old, new); |
285 | } while (prev != old); | |
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 | } | |
291 | wake_up_interruptible(&dev->lock.lock_queue); | |
292 | return 0; | |
293 | } | |
294 | ||
295 | /** | |
296 | * If we get here, it means that the process has called DRM_IOCTL_LOCK | |
297 | * without calling DRM_IOCTL_UNLOCK. | |
298 | * | |
299 | * If the lock is not held, then let the signal proceed as usual. If the lock | |
300 | * is held, then set the contended flag and keep the signal blocked. | |
301 | * | |
302 | * \param priv pointer to a drm_sigdata structure. | |
303 | * \return one if the signal should be delivered normally, or zero if the | |
304 | * signal should be blocked. | |
305 | */ | |
c94f7029 | 306 | static int drm_notifier(void *priv) |
1da177e4 | 307 | { |
b5e89ed5 DA |
308 | drm_sigdata_t *s = (drm_sigdata_t *) priv; |
309 | unsigned int old, new, prev; | |
1da177e4 | 310 | |
b5e89ed5 | 311 | /* Allow signal delivery if lock isn't held */ |
1da177e4 | 312 | if (!s->lock || !_DRM_LOCK_IS_HELD(s->lock->lock) |
b5e89ed5 DA |
313 | || _DRM_LOCKING_CONTEXT(s->lock->lock) != s->context) |
314 | return 1; | |
1da177e4 | 315 | |
b5e89ed5 DA |
316 | /* Otherwise, set flag to force call to |
317 | drmUnlock */ | |
1da177e4 | 318 | do { |
b5e89ed5 DA |
319 | old = s->lock->lock; |
320 | new = old | _DRM_LOCK_CONT; | |
1da177e4 LT |
321 | prev = cmpxchg(&s->lock->lock, old, new); |
322 | } while (prev != old); | |
323 | return 0; | |
324 | } |