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Commit | Line | Data |
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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> |
3f07c014 IM |
37 | #include <linux/sched/signal.h> |
38 | ||
760285e7 | 39 | #include <drm/drmP.h> |
e7b96070 | 40 | #include "drm_legacy.h" |
44af3f5c | 41 | #include "drm_internal.h" |
1da177e4 | 42 | |
4ac5ec40 DV |
43 | static int drm_lock_take(struct drm_lock_data *lock_data, unsigned int context); |
44 | ||
1a75a222 DV |
45 | /** |
46 | * Take the heavyweight lock. | |
47 | * | |
48 | * \param lock lock pointer. | |
49 | * \param context locking context. | |
50 | * \return one if the lock is held, or zero otherwise. | |
51 | * | |
52 | * Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction. | |
53 | */ | |
54 | static | |
55 | int drm_lock_take(struct drm_lock_data *lock_data, | |
56 | unsigned int context) | |
57 | { | |
58 | unsigned int old, new, prev; | |
59 | volatile unsigned int *lock = &lock_data->hw_lock->lock; | |
60 | ||
61 | spin_lock_bh(&lock_data->spinlock); | |
62 | do { | |
63 | old = *lock; | |
64 | if (old & _DRM_LOCK_HELD) | |
65 | new = old | _DRM_LOCK_CONT; | |
66 | else { | |
67 | new = context | _DRM_LOCK_HELD | | |
68 | ((lock_data->user_waiters + lock_data->kernel_waiters > 1) ? | |
69 | _DRM_LOCK_CONT : 0); | |
70 | } | |
71 | prev = cmpxchg(lock, old, new); | |
72 | } while (prev != old); | |
73 | spin_unlock_bh(&lock_data->spinlock); | |
74 | ||
75 | if (_DRM_LOCKING_CONTEXT(old) == context) { | |
76 | if (old & _DRM_LOCK_HELD) { | |
77 | if (context != DRM_KERNEL_CONTEXT) { | |
78 | DRM_ERROR("%d holds heavyweight lock\n", | |
79 | context); | |
80 | } | |
81 | return 0; | |
82 | } | |
83 | } | |
84 | ||
85 | if ((_DRM_LOCKING_CONTEXT(new)) == context && (new & _DRM_LOCK_HELD)) { | |
86 | /* Have lock */ | |
87 | return 1; | |
88 | } | |
89 | return 0; | |
90 | } | |
91 | ||
92 | /** | |
93 | * This takes a lock forcibly and hands it to context. Should ONLY be used | |
94 | * inside *_unlock to give lock to kernel before calling *_dma_schedule. | |
95 | * | |
96 | * \param dev DRM device. | |
97 | * \param lock lock pointer. | |
98 | * \param context locking context. | |
99 | * \return always one. | |
100 | * | |
101 | * Resets the lock file pointer. | |
102 | * Marks the lock as held by the given context, via the \p cmpxchg instruction. | |
103 | */ | |
104 | static int drm_lock_transfer(struct drm_lock_data *lock_data, | |
105 | unsigned int context) | |
106 | { | |
107 | unsigned int old, new, prev; | |
108 | volatile unsigned int *lock = &lock_data->hw_lock->lock; | |
109 | ||
110 | lock_data->file_priv = NULL; | |
111 | do { | |
112 | old = *lock; | |
113 | new = context | _DRM_LOCK_HELD; | |
114 | prev = cmpxchg(lock, old, new); | |
115 | } while (prev != old); | |
116 | return 1; | |
117 | } | |
118 | ||
119 | static int drm_legacy_lock_free(struct drm_lock_data *lock_data, | |
120 | unsigned int context) | |
121 | { | |
122 | unsigned int old, new, prev; | |
123 | volatile unsigned int *lock = &lock_data->hw_lock->lock; | |
124 | ||
125 | spin_lock_bh(&lock_data->spinlock); | |
126 | if (lock_data->kernel_waiters != 0) { | |
127 | drm_lock_transfer(lock_data, 0); | |
128 | lock_data->idle_has_lock = 1; | |
129 | spin_unlock_bh(&lock_data->spinlock); | |
130 | return 1; | |
131 | } | |
132 | spin_unlock_bh(&lock_data->spinlock); | |
133 | ||
134 | do { | |
135 | old = *lock; | |
136 | new = _DRM_LOCKING_CONTEXT(old); | |
137 | prev = cmpxchg(lock, old, new); | |
138 | } while (prev != old); | |
139 | ||
140 | if (_DRM_LOCK_IS_HELD(old) && _DRM_LOCKING_CONTEXT(old) != context) { | |
141 | DRM_ERROR("%d freed heavyweight lock held by %d\n", | |
142 | context, _DRM_LOCKING_CONTEXT(old)); | |
143 | return 1; | |
144 | } | |
145 | wake_up_interruptible(&lock_data->lock_queue); | |
146 | return 0; | |
147 | } | |
148 | ||
b5e89ed5 | 149 | /** |
1da177e4 LT |
150 | * Lock ioctl. |
151 | * | |
152 | * \param inode device inode. | |
6c340eac | 153 | * \param file_priv DRM file private. |
1da177e4 LT |
154 | * \param cmd command. |
155 | * \param arg user argument, pointing to a drm_lock structure. | |
156 | * \return zero on success or negative number on failure. | |
157 | * | |
158 | * Add the current task to the lock wait queue, and attempt to take to lock. | |
159 | */ | |
bb6d822e DH |
160 | int drm_legacy_lock(struct drm_device *dev, void *data, |
161 | struct drm_file *file_priv) | |
1da177e4 | 162 | { |
b5e89ed5 | 163 | DECLARE_WAITQUEUE(entry, current); |
c153f45f | 164 | struct drm_lock *lock = data; |
7c1c2871 | 165 | struct drm_master *master = file_priv->master; |
b5e89ed5 | 166 | int ret = 0; |
1da177e4 | 167 | |
fa538645 | 168 | if (!drm_core_check_feature(dev, DRIVER_LEGACY)) |
da168d81 DV |
169 | return -EINVAL; |
170 | ||
6c340eac | 171 | ++file_priv->lock_count; |
1da177e4 | 172 | |
c153f45f | 173 | if (lock->context == DRM_KERNEL_CONTEXT) { |
b5e89ed5 | 174 | DRM_ERROR("Process %d using kernel context %d\n", |
ba25f9dc | 175 | task_pid_nr(current), lock->context); |
b5e89ed5 DA |
176 | return -EINVAL; |
177 | } | |
1da177e4 | 178 | |
b5e89ed5 | 179 | DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n", |
ba25f9dc | 180 | lock->context, task_pid_nr(current), |
a2ec1c13 CW |
181 | master->lock.hw_lock ? master->lock.hw_lock->lock : -1, |
182 | lock->flags); | |
1da177e4 | 183 | |
7c1c2871 DA |
184 | add_wait_queue(&master->lock.lock_queue, &entry); |
185 | spin_lock_bh(&master->lock.spinlock); | |
186 | master->lock.user_waiters++; | |
187 | spin_unlock_bh(&master->lock.spinlock); | |
188 | ||
1da177e4 LT |
189 | for (;;) { |
190 | __set_current_state(TASK_INTERRUPTIBLE); | |
7c1c2871 | 191 | if (!master->lock.hw_lock) { |
1da177e4 | 192 | /* Device has been unregistered */ |
fda714c2 | 193 | send_sig(SIGTERM, current, 0); |
1da177e4 LT |
194 | ret = -EINTR; |
195 | break; | |
196 | } | |
7c1c2871 DA |
197 | if (drm_lock_take(&master->lock, lock->context)) { |
198 | master->lock.file_priv = file_priv; | |
199 | master->lock.lock_time = jiffies; | |
b5e89ed5 | 200 | break; /* Got lock */ |
1da177e4 | 201 | } |
b5e89ed5 | 202 | |
1da177e4 | 203 | /* Contention */ |
08f2e669 | 204 | mutex_unlock(&drm_global_mutex); |
1da177e4 | 205 | schedule(); |
08f2e669 | 206 | mutex_lock(&drm_global_mutex); |
b5e89ed5 | 207 | if (signal_pending(current)) { |
4d77c88e | 208 | ret = -EINTR; |
1da177e4 LT |
209 | break; |
210 | } | |
211 | } | |
7c1c2871 DA |
212 | spin_lock_bh(&master->lock.spinlock); |
213 | master->lock.user_waiters--; | |
214 | spin_unlock_bh(&master->lock.spinlock); | |
1da177e4 | 215 | __set_current_state(TASK_RUNNING); |
7c1c2871 | 216 | remove_wait_queue(&master->lock.lock_queue, &entry); |
1da177e4 | 217 | |
c153f45f EA |
218 | DRM_DEBUG("%d %s\n", lock->context, |
219 | ret ? "interrupted" : "has lock"); | |
040ac320 | 220 | if (ret) return ret; |
d985c108 | 221 | |
3e5fc80a DA |
222 | /* don't set the block all signals on the master process for now |
223 | * really probably not the correct answer but lets us debug xkb | |
224 | * xserver for now */ | |
b3ac9f25 | 225 | if (!drm_is_current_master(file_priv)) { |
3e5fc80a | 226 | dev->sigdata.context = lock->context; |
7c1c2871 | 227 | dev->sigdata.lock = master->lock.hw_lock; |
3e5fc80a | 228 | } |
b5e89ed5 | 229 | |
c153f45f EA |
230 | if (dev->driver->dma_quiescent && (lock->flags & _DRM_LOCK_QUIESCENT)) |
231 | { | |
d985c108 | 232 | if (dev->driver->dma_quiescent(dev)) { |
c153f45f EA |
233 | DRM_DEBUG("%d waiting for DMA quiescent\n", |
234 | lock->context); | |
20caafa6 | 235 | return -EBUSY; |
d985c108 DA |
236 | } |
237 | } | |
b5e89ed5 | 238 | |
d985c108 | 239 | return 0; |
1da177e4 LT |
240 | } |
241 | ||
b5e89ed5 | 242 | /** |
1da177e4 LT |
243 | * Unlock ioctl. |
244 | * | |
245 | * \param inode device inode. | |
6c340eac | 246 | * \param file_priv DRM file private. |
1da177e4 LT |
247 | * \param cmd command. |
248 | * \param arg user argument, pointing to a drm_lock structure. | |
249 | * \return zero on success or negative number on failure. | |
250 | * | |
251 | * Transfer and free the lock. | |
252 | */ | |
bb6d822e | 253 | int drm_legacy_unlock(struct drm_device *dev, void *data, struct drm_file *file_priv) |
1da177e4 | 254 | { |
c153f45f | 255 | struct drm_lock *lock = data; |
45ff46c5 | 256 | struct drm_master *master = file_priv->master; |
1da177e4 | 257 | |
fa538645 | 258 | if (!drm_core_check_feature(dev, DRIVER_LEGACY)) |
da168d81 DV |
259 | return -EINVAL; |
260 | ||
c153f45f | 261 | if (lock->context == DRM_KERNEL_CONTEXT) { |
b5e89ed5 | 262 | DRM_ERROR("Process %d using kernel context %d\n", |
ba25f9dc | 263 | task_pid_nr(current), lock->context); |
1da177e4 LT |
264 | return -EINVAL; |
265 | } | |
266 | ||
bb6d822e | 267 | if (drm_legacy_lock_free(&master->lock, lock->context)) { |
45ff46c5 DV |
268 | /* FIXME: Should really bail out here. */ |
269 | } | |
270 | ||
1da177e4 LT |
271 | return 0; |
272 | } | |
273 | ||
040ac320 TH |
274 | /** |
275 | * This function returns immediately and takes the hw lock | |
276 | * with the kernel context if it is free, otherwise it gets the highest priority when and if | |
277 | * it is eventually released. | |
278 | * | |
279 | * This guarantees that the kernel will _eventually_ have the lock _unless_ it is held | |
280 | * by a blocked process. (In the latter case an explicit wait for the hardware lock would cause | |
281 | * a deadlock, which is why the "idlelock" was invented). | |
282 | * | |
283 | * This should be sufficient to wait for GPU idle without | |
284 | * having to worry about starvation. | |
285 | */ | |
286 | ||
bb6d822e | 287 | void drm_legacy_idlelock_take(struct drm_lock_data *lock_data) |
040ac320 | 288 | { |
4a1b0714 | 289 | int ret; |
040ac320 | 290 | |
f116cc56 | 291 | spin_lock_bh(&lock_data->spinlock); |
040ac320 TH |
292 | lock_data->kernel_waiters++; |
293 | if (!lock_data->idle_has_lock) { | |
294 | ||
f116cc56 | 295 | spin_unlock_bh(&lock_data->spinlock); |
040ac320 | 296 | ret = drm_lock_take(lock_data, DRM_KERNEL_CONTEXT); |
f116cc56 | 297 | spin_lock_bh(&lock_data->spinlock); |
040ac320 TH |
298 | |
299 | if (ret == 1) | |
300 | lock_data->idle_has_lock = 1; | |
301 | } | |
f116cc56 | 302 | spin_unlock_bh(&lock_data->spinlock); |
040ac320 | 303 | } |
bb6d822e | 304 | EXPORT_SYMBOL(drm_legacy_idlelock_take); |
040ac320 | 305 | |
bb6d822e | 306 | void drm_legacy_idlelock_release(struct drm_lock_data *lock_data) |
040ac320 TH |
307 | { |
308 | unsigned int old, prev; | |
309 | volatile unsigned int *lock = &lock_data->hw_lock->lock; | |
310 | ||
f116cc56 | 311 | spin_lock_bh(&lock_data->spinlock); |
040ac320 TH |
312 | if (--lock_data->kernel_waiters == 0) { |
313 | if (lock_data->idle_has_lock) { | |
314 | do { | |
315 | old = *lock; | |
316 | prev = cmpxchg(lock, old, DRM_KERNEL_CONTEXT); | |
317 | } while (prev != old); | |
318 | wake_up_interruptible(&lock_data->lock_queue); | |
319 | lock_data->idle_has_lock = 0; | |
320 | } | |
321 | } | |
f116cc56 | 322 | spin_unlock_bh(&lock_data->spinlock); |
040ac320 | 323 | } |
bb6d822e | 324 | EXPORT_SYMBOL(drm_legacy_idlelock_release); |
040ac320 | 325 | |
1a75a222 DV |
326 | static int drm_legacy_i_have_hw_lock(struct drm_device *dev, |
327 | struct drm_file *file_priv) | |
040ac320 | 328 | { |
7c1c2871 DA |
329 | struct drm_master *master = file_priv->master; |
330 | return (file_priv->lock_count && master->lock.hw_lock && | |
331 | _DRM_LOCK_IS_HELD(master->lock.hw_lock->lock) && | |
332 | master->lock.file_priv == file_priv); | |
040ac320 | 333 | } |
1a75a222 DV |
334 | |
335 | void drm_legacy_lock_release(struct drm_device *dev, struct file *filp) | |
336 | { | |
337 | struct drm_file *file_priv = filp->private_data; | |
338 | ||
339 | /* if the master has gone away we can't do anything with the lock */ | |
95c081c1 | 340 | if (!dev->master) |
1a75a222 DV |
341 | return; |
342 | ||
343 | if (drm_legacy_i_have_hw_lock(dev, file_priv)) { | |
344 | DRM_DEBUG("File %p released, freeing lock for context %d\n", | |
345 | filp, _DRM_LOCKING_CONTEXT(file_priv->master->lock.hw_lock->lock)); | |
346 | drm_legacy_lock_free(&file_priv->master->lock, | |
347 | _DRM_LOCKING_CONTEXT(file_priv->master->lock.hw_lock->lock)); | |
348 | } | |
349 | } |