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 | ||
b5e89ed5 | 43 | /** |
1da177e4 LT |
44 | * Lock ioctl. |
45 | * | |
46 | * \param inode device inode. | |
6c340eac | 47 | * \param file_priv DRM file private. |
1da177e4 LT |
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 | */ | |
bb6d822e DH |
54 | int drm_legacy_lock(struct drm_device *dev, void *data, |
55 | struct drm_file *file_priv) | |
1da177e4 | 56 | { |
b5e89ed5 | 57 | DECLARE_WAITQUEUE(entry, current); |
c153f45f | 58 | struct drm_lock *lock = data; |
7c1c2871 | 59 | struct drm_master *master = file_priv->master; |
b5e89ed5 | 60 | int ret = 0; |
1da177e4 | 61 | |
da168d81 DV |
62 | if (drm_core_check_feature(dev, DRIVER_MODESET)) |
63 | return -EINVAL; | |
64 | ||
6c340eac | 65 | ++file_priv->lock_count; |
1da177e4 | 66 | |
c153f45f | 67 | if (lock->context == DRM_KERNEL_CONTEXT) { |
b5e89ed5 | 68 | DRM_ERROR("Process %d using kernel context %d\n", |
ba25f9dc | 69 | task_pid_nr(current), lock->context); |
b5e89ed5 DA |
70 | return -EINVAL; |
71 | } | |
1da177e4 | 72 | |
b5e89ed5 | 73 | DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n", |
ba25f9dc | 74 | lock->context, task_pid_nr(current), |
7c1c2871 | 75 | master->lock.hw_lock->lock, lock->flags); |
1da177e4 | 76 | |
7c1c2871 DA |
77 | add_wait_queue(&master->lock.lock_queue, &entry); |
78 | spin_lock_bh(&master->lock.spinlock); | |
79 | master->lock.user_waiters++; | |
80 | spin_unlock_bh(&master->lock.spinlock); | |
81 | ||
1da177e4 LT |
82 | for (;;) { |
83 | __set_current_state(TASK_INTERRUPTIBLE); | |
7c1c2871 | 84 | if (!master->lock.hw_lock) { |
1da177e4 | 85 | /* Device has been unregistered */ |
fda714c2 | 86 | send_sig(SIGTERM, current, 0); |
1da177e4 LT |
87 | ret = -EINTR; |
88 | break; | |
89 | } | |
7c1c2871 DA |
90 | if (drm_lock_take(&master->lock, lock->context)) { |
91 | master->lock.file_priv = file_priv; | |
92 | master->lock.lock_time = jiffies; | |
b5e89ed5 | 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 */ | |
7963e9db | 118 | if (!file_priv->is_master) { |
3e5fc80a | 119 | dev->sigdata.context = lock->context; |
7c1c2871 | 120 | dev->sigdata.lock = master->lock.hw_lock; |
3e5fc80a | 121 | } |
b5e89ed5 | 122 | |
c153f45f EA |
123 | if (dev->driver->dma_quiescent && (lock->flags & _DRM_LOCK_QUIESCENT)) |
124 | { | |
d985c108 | 125 | if (dev->driver->dma_quiescent(dev)) { |
c153f45f EA |
126 | DRM_DEBUG("%d waiting for DMA quiescent\n", |
127 | lock->context); | |
20caafa6 | 128 | return -EBUSY; |
d985c108 DA |
129 | } |
130 | } | |
b5e89ed5 | 131 | |
d985c108 | 132 | return 0; |
1da177e4 LT |
133 | } |
134 | ||
b5e89ed5 | 135 | /** |
1da177e4 LT |
136 | * Unlock ioctl. |
137 | * | |
138 | * \param inode device inode. | |
6c340eac | 139 | * \param file_priv DRM file private. |
1da177e4 LT |
140 | * \param cmd command. |
141 | * \param arg user argument, pointing to a drm_lock structure. | |
142 | * \return zero on success or negative number on failure. | |
143 | * | |
144 | * Transfer and free the lock. | |
145 | */ | |
bb6d822e | 146 | int drm_legacy_unlock(struct drm_device *dev, void *data, struct drm_file *file_priv) |
1da177e4 | 147 | { |
c153f45f | 148 | struct drm_lock *lock = data; |
45ff46c5 | 149 | struct drm_master *master = file_priv->master; |
1da177e4 | 150 | |
da168d81 DV |
151 | if (drm_core_check_feature(dev, DRIVER_MODESET)) |
152 | return -EINVAL; | |
153 | ||
c153f45f | 154 | if (lock->context == DRM_KERNEL_CONTEXT) { |
b5e89ed5 | 155 | DRM_ERROR("Process %d using kernel context %d\n", |
ba25f9dc | 156 | task_pid_nr(current), lock->context); |
1da177e4 LT |
157 | return -EINVAL; |
158 | } | |
159 | ||
bb6d822e | 160 | if (drm_legacy_lock_free(&master->lock, lock->context)) { |
45ff46c5 DV |
161 | /* FIXME: Should really bail out here. */ |
162 | } | |
163 | ||
1da177e4 LT |
164 | return 0; |
165 | } | |
166 | ||
167 | /** | |
168 | * Take the heavyweight lock. | |
169 | * | |
170 | * \param lock lock pointer. | |
171 | * \param context locking context. | |
172 | * \return one if the lock is held, or zero otherwise. | |
173 | * | |
174 | * Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction. | |
175 | */ | |
4ac5ec40 | 176 | static |
55910517 | 177 | int drm_lock_take(struct drm_lock_data *lock_data, |
040ac320 | 178 | unsigned int context) |
1da177e4 LT |
179 | { |
180 | unsigned int old, new, prev; | |
040ac320 | 181 | volatile unsigned int *lock = &lock_data->hw_lock->lock; |
1da177e4 | 182 | |
f116cc56 | 183 | spin_lock_bh(&lock_data->spinlock); |
1da177e4 LT |
184 | do { |
185 | old = *lock; | |
b5e89ed5 DA |
186 | if (old & _DRM_LOCK_HELD) |
187 | new = old | _DRM_LOCK_CONT; | |
040ac320 TH |
188 | else { |
189 | new = context | _DRM_LOCK_HELD | | |
190 | ((lock_data->user_waiters + lock_data->kernel_waiters > 1) ? | |
191 | _DRM_LOCK_CONT : 0); | |
192 | } | |
1da177e4 LT |
193 | prev = cmpxchg(lock, old, new); |
194 | } while (prev != old); | |
f116cc56 | 195 | spin_unlock_bh(&lock_data->spinlock); |
040ac320 | 196 | |
1da177e4 LT |
197 | if (_DRM_LOCKING_CONTEXT(old) == context) { |
198 | if (old & _DRM_LOCK_HELD) { | |
199 | if (context != DRM_KERNEL_CONTEXT) { | |
200 | DRM_ERROR("%d holds heavyweight lock\n", | |
201 | context); | |
202 | } | |
203 | return 0; | |
204 | } | |
205 | } | |
040ac320 TH |
206 | |
207 | if ((_DRM_LOCKING_CONTEXT(new)) == context && (new & _DRM_LOCK_HELD)) { | |
b5e89ed5 | 208 | /* Have lock */ |
1da177e4 LT |
209 | return 1; |
210 | } | |
211 | return 0; | |
212 | } | |
213 | ||
214 | /** | |
215 | * This takes a lock forcibly and hands it to context. Should ONLY be used | |
b5e89ed5 DA |
216 | * inside *_unlock to give lock to kernel before calling *_dma_schedule. |
217 | * | |
1da177e4 LT |
218 | * \param dev DRM device. |
219 | * \param lock lock pointer. | |
220 | * \param context locking context. | |
221 | * \return always one. | |
222 | * | |
223 | * Resets the lock file pointer. | |
224 | * Marks the lock as held by the given context, via the \p cmpxchg instruction. | |
225 | */ | |
55910517 | 226 | static int drm_lock_transfer(struct drm_lock_data *lock_data, |
c94f7029 | 227 | unsigned int context) |
1da177e4 LT |
228 | { |
229 | unsigned int old, new, prev; | |
040ac320 | 230 | volatile unsigned int *lock = &lock_data->hw_lock->lock; |
1da177e4 | 231 | |
6c340eac | 232 | lock_data->file_priv = NULL; |
1da177e4 | 233 | do { |
b5e89ed5 DA |
234 | old = *lock; |
235 | new = context | _DRM_LOCK_HELD; | |
1da177e4 LT |
236 | prev = cmpxchg(lock, old, new); |
237 | } while (prev != old); | |
238 | return 1; | |
239 | } | |
240 | ||
241 | /** | |
242 | * Free lock. | |
b5e89ed5 | 243 | * |
1da177e4 LT |
244 | * \param dev DRM device. |
245 | * \param lock lock. | |
246 | * \param context context. | |
b5e89ed5 | 247 | * |
1da177e4 LT |
248 | * Resets the lock file pointer. |
249 | * Marks the lock as not held, via the \p cmpxchg instruction. Wakes any task | |
250 | * waiting on the lock queue. | |
251 | */ | |
bb6d822e | 252 | int drm_legacy_lock_free(struct drm_lock_data *lock_data, unsigned int context) |
1da177e4 LT |
253 | { |
254 | unsigned int old, new, prev; | |
040ac320 TH |
255 | volatile unsigned int *lock = &lock_data->hw_lock->lock; |
256 | ||
f116cc56 | 257 | spin_lock_bh(&lock_data->spinlock); |
040ac320 TH |
258 | if (lock_data->kernel_waiters != 0) { |
259 | drm_lock_transfer(lock_data, 0); | |
260 | lock_data->idle_has_lock = 1; | |
f116cc56 | 261 | spin_unlock_bh(&lock_data->spinlock); |
040ac320 TH |
262 | return 1; |
263 | } | |
f116cc56 | 264 | spin_unlock_bh(&lock_data->spinlock); |
1da177e4 | 265 | |
1da177e4 | 266 | do { |
b5e89ed5 | 267 | old = *lock; |
040ac320 | 268 | new = _DRM_LOCKING_CONTEXT(old); |
1da177e4 LT |
269 | prev = cmpxchg(lock, old, new); |
270 | } while (prev != old); | |
040ac320 | 271 | |
1da177e4 LT |
272 | if (_DRM_LOCK_IS_HELD(old) && _DRM_LOCKING_CONTEXT(old) != context) { |
273 | DRM_ERROR("%d freed heavyweight lock held by %d\n", | |
b5e89ed5 | 274 | context, _DRM_LOCKING_CONTEXT(old)); |
1da177e4 LT |
275 | return 1; |
276 | } | |
040ac320 | 277 | wake_up_interruptible(&lock_data->lock_queue); |
1da177e4 LT |
278 | return 0; |
279 | } | |
280 | ||
040ac320 TH |
281 | /** |
282 | * This function returns immediately and takes the hw lock | |
283 | * with the kernel context if it is free, otherwise it gets the highest priority when and if | |
284 | * it is eventually released. | |
285 | * | |
286 | * This guarantees that the kernel will _eventually_ have the lock _unless_ it is held | |
287 | * by a blocked process. (In the latter case an explicit wait for the hardware lock would cause | |
288 | * a deadlock, which is why the "idlelock" was invented). | |
289 | * | |
290 | * This should be sufficient to wait for GPU idle without | |
291 | * having to worry about starvation. | |
292 | */ | |
293 | ||
bb6d822e | 294 | void drm_legacy_idlelock_take(struct drm_lock_data *lock_data) |
040ac320 | 295 | { |
4a1b0714 | 296 | int ret; |
040ac320 | 297 | |
f116cc56 | 298 | spin_lock_bh(&lock_data->spinlock); |
040ac320 TH |
299 | lock_data->kernel_waiters++; |
300 | if (!lock_data->idle_has_lock) { | |
301 | ||
f116cc56 | 302 | spin_unlock_bh(&lock_data->spinlock); |
040ac320 | 303 | ret = drm_lock_take(lock_data, DRM_KERNEL_CONTEXT); |
f116cc56 | 304 | spin_lock_bh(&lock_data->spinlock); |
040ac320 TH |
305 | |
306 | if (ret == 1) | |
307 | lock_data->idle_has_lock = 1; | |
308 | } | |
f116cc56 | 309 | spin_unlock_bh(&lock_data->spinlock); |
040ac320 | 310 | } |
bb6d822e | 311 | EXPORT_SYMBOL(drm_legacy_idlelock_take); |
040ac320 | 312 | |
bb6d822e | 313 | void drm_legacy_idlelock_release(struct drm_lock_data *lock_data) |
040ac320 TH |
314 | { |
315 | unsigned int old, prev; | |
316 | volatile unsigned int *lock = &lock_data->hw_lock->lock; | |
317 | ||
f116cc56 | 318 | spin_lock_bh(&lock_data->spinlock); |
040ac320 TH |
319 | if (--lock_data->kernel_waiters == 0) { |
320 | if (lock_data->idle_has_lock) { | |
321 | do { | |
322 | old = *lock; | |
323 | prev = cmpxchg(lock, old, DRM_KERNEL_CONTEXT); | |
324 | } while (prev != old); | |
325 | wake_up_interruptible(&lock_data->lock_queue); | |
326 | lock_data->idle_has_lock = 0; | |
327 | } | |
328 | } | |
f116cc56 | 329 | spin_unlock_bh(&lock_data->spinlock); |
040ac320 | 330 | } |
bb6d822e | 331 | EXPORT_SYMBOL(drm_legacy_idlelock_release); |
040ac320 | 332 | |
bb6d822e DH |
333 | int drm_legacy_i_have_hw_lock(struct drm_device *dev, |
334 | struct drm_file *file_priv) | |
040ac320 | 335 | { |
7c1c2871 DA |
336 | struct drm_master *master = file_priv->master; |
337 | return (file_priv->lock_count && master->lock.hw_lock && | |
338 | _DRM_LOCK_IS_HELD(master->lock.hw_lock->lock) && | |
339 | master->lock.file_priv == file_priv); | |
040ac320 | 340 | } |