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