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36#include <linux/export.h>
37#include <drm/drmP.h>
38#include "drm_legacy.h"
39#include "drm_internal.h"
40
41static int drm_lock_take(struct drm_lock_data *lock_data, unsigned int context);
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51
52static
53int 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
85 return 1;
86 }
87 return 0;
88}
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101
102static 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
117static 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
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156
157
158int drm_legacy_lock(struct drm_device *dev, void *data,
159 struct drm_file *file_priv)
160{
161 DECLARE_WAITQUEUE(entry, current);
162 struct drm_lock *lock = data;
163 struct drm_master *master = file_priv->master;
164 int ret = 0;
165
166 if (drm_core_check_feature(dev, DRIVER_MODESET))
167 return -EINVAL;
168
169 ++file_priv->lock_count;
170
171 if (lock->context == DRM_KERNEL_CONTEXT) {
172 DRM_ERROR("Process %d using kernel context %d\n",
173 task_pid_nr(current), lock->context);
174 return -EINVAL;
175 }
176
177 DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n",
178 lock->context, task_pid_nr(current),
179 master->lock.hw_lock->lock, lock->flags);
180
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
186 for (;;) {
187 __set_current_state(TASK_INTERRUPTIBLE);
188 if (!master->lock.hw_lock) {
189
190 send_sig(SIGTERM, current, 0);
191 ret = -EINTR;
192 break;
193 }
194 if (drm_lock_take(&master->lock, lock->context)) {
195 master->lock.file_priv = file_priv;
196 master->lock.lock_time = jiffies;
197 break;
198 }
199
200
201 mutex_unlock(&drm_global_mutex);
202 schedule();
203 mutex_lock(&drm_global_mutex);
204 if (signal_pending(current)) {
205 ret = -EINTR;
206 break;
207 }
208 }
209 spin_lock_bh(&master->lock.spinlock);
210 master->lock.user_waiters--;
211 spin_unlock_bh(&master->lock.spinlock);
212 __set_current_state(TASK_RUNNING);
213 remove_wait_queue(&master->lock.lock_queue, &entry);
214
215 DRM_DEBUG("%d %s\n", lock->context,
216 ret ? "interrupted" : "has lock");
217 if (ret) return ret;
218
219
220
221
222 if (!drm_is_current_master(file_priv)) {
223 dev->sigdata.context = lock->context;
224 dev->sigdata.lock = master->lock.hw_lock;
225 }
226
227 if (dev->driver->dma_quiescent && (lock->flags & _DRM_LOCK_QUIESCENT))
228 {
229 if (dev->driver->dma_quiescent(dev)) {
230 DRM_DEBUG("%d waiting for DMA quiescent\n",
231 lock->context);
232 return -EBUSY;
233 }
234 }
235
236 return 0;
237}
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249
250int drm_legacy_unlock(struct drm_device *dev, void *data, struct drm_file *file_priv)
251{
252 struct drm_lock *lock = data;
253 struct drm_master *master = file_priv->master;
254
255 if (drm_core_check_feature(dev, DRIVER_MODESET))
256 return -EINVAL;
257
258 if (lock->context == DRM_KERNEL_CONTEXT) {
259 DRM_ERROR("Process %d using kernel context %d\n",
260 task_pid_nr(current), lock->context);
261 return -EINVAL;
262 }
263
264 if (drm_legacy_lock_free(&master->lock, lock->context)) {
265
266 }
267
268 return 0;
269}
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283
284void drm_legacy_idlelock_take(struct drm_lock_data *lock_data)
285{
286 int ret;
287
288 spin_lock_bh(&lock_data->spinlock);
289 lock_data->kernel_waiters++;
290 if (!lock_data->idle_has_lock) {
291
292 spin_unlock_bh(&lock_data->spinlock);
293 ret = drm_lock_take(lock_data, DRM_KERNEL_CONTEXT);
294 spin_lock_bh(&lock_data->spinlock);
295
296 if (ret == 1)
297 lock_data->idle_has_lock = 1;
298 }
299 spin_unlock_bh(&lock_data->spinlock);
300}
301EXPORT_SYMBOL(drm_legacy_idlelock_take);
302
303void drm_legacy_idlelock_release(struct drm_lock_data *lock_data)
304{
305 unsigned int old, prev;
306 volatile unsigned int *lock = &lock_data->hw_lock->lock;
307
308 spin_lock_bh(&lock_data->spinlock);
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 }
319 spin_unlock_bh(&lock_data->spinlock);
320}
321EXPORT_SYMBOL(drm_legacy_idlelock_release);
322
323static int drm_legacy_i_have_hw_lock(struct drm_device *dev,
324 struct drm_file *file_priv)
325{
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);
330}
331
332void drm_legacy_lock_release(struct drm_device *dev, struct file *filp)
333{
334 struct drm_file *file_priv = filp->private_data;
335
336
337 if (!dev->master)
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}
347