blob: 116ed0f2ac09738e500ce038470d63845c019762 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/**
Dave Airlieb5e89ed2005-09-25 14:28:13 +10002 * \file drm_lock.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 * IOCTLs for locking
Dave Airlieb5e89ed2005-09-25 14:28:13 +10004 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07005 * \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
Dave Airlieb5e89ed2005-09-25 14:28:13 +100038static int drm_lock_transfer(drm_device_t * dev,
Dave Airliec94f7022005-07-07 21:03:38 +100039 __volatile__ unsigned int *lock,
40 unsigned int context);
41static int drm_notifier(void *priv);
42
Dave Airlieb5e89ed2005-09-25 14:28:13 +100043/**
Linus Torvalds1da177e2005-04-16 15:20:36 -070044 * 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 */
Dave Airlieb5e89ed2005-09-25 14:28:13 +100054int drm_lock(struct inode *inode, struct file *filp,
55 unsigned int cmd, unsigned long arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -070056{
Dave Airlieb5e89ed2005-09-25 14:28:13 +100057 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;
Linus Torvalds1da177e2005-04-16 15:20:36 -070062
63 ++priv->lock_count;
64
Dave Airlieb5e89ed2005-09-25 14:28:13 +100065 if (copy_from_user(&lock, (drm_lock_t __user *) arg, sizeof(lock)))
Linus Torvalds1da177e2005-04-16 15:20:36 -070066 return -EFAULT;
67
Dave Airlieb5e89ed2005-09-25 14:28:13 +100068 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 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070073
Dave Airlieb5e89ed2005-09-25 14:28:13 +100074 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);
Linus Torvalds1da177e2005-04-16 15:20:36 -070077
78 if (drm_core_check_feature(dev, DRIVER_DMA_QUEUE))
Dave Airlieb5e89ed2005-09-25 14:28:13 +100079 if (lock.context < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -070080 return -EINVAL;
81
Dave Airlieb5e89ed2005-09-25 14:28:13 +100082 add_wait_queue(&dev->lock.lock_queue, &entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -070083 for (;;) {
84 __set_current_state(TASK_INTERRUPTIBLE);
Dave Airlieb5e89ed2005-09-25 14:28:13 +100085 if (!dev->lock.hw_lock) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070086 /* Device has been unregistered */
87 ret = -EINTR;
88 break;
89 }
Dave Airlieb5e89ed2005-09-25 14:28:13 +100090 if (drm_lock_take(&dev->lock.hw_lock->lock, lock.context)) {
91 dev->lock.filp = filp;
Linus Torvalds1da177e2005-04-16 15:20:36 -070092 dev->lock.lock_time = jiffies;
Dave Airlieb5e89ed2005-09-25 14:28:13 +100093 atomic_inc(&dev->counts[_DRM_STAT_LOCKS]);
94 break; /* Got lock */
Linus Torvalds1da177e2005-04-16 15:20:36 -070095 }
Dave Airlieb5e89ed2005-09-25 14:28:13 +100096
Linus Torvalds1da177e2005-04-16 15:20:36 -070097 /* Contention */
98 schedule();
Dave Airlieb5e89ed2005-09-25 14:28:13 +100099 if (signal_pending(current)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100 ret = -ERESTARTSYS;
101 break;
102 }
103 }
104 __set_current_state(TASK_RUNNING);
Dave Airlieb5e89ed2005-09-25 14:28:13 +1000105 remove_wait_queue(&dev->lock.lock_queue, &entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106
Dave Airliecf65f162005-11-24 21:41:14 +1100107 DRM_DEBUG("%d %s\n", lock.context, ret ? "interrupted" : "has lock");
108 if (ret)
109 return ret;
Dave Airlied985c102006-01-02 21:32:48 +1100110
Dave Airlieb5e89ed2005-09-25 14:28:13 +1000111 sigemptyset(&dev->sigmask);
112 sigaddset(&dev->sigmask, SIGSTOP);
113 sigaddset(&dev->sigmask, SIGTSTP);
114 sigaddset(&dev->sigmask, SIGTTIN);
115 sigaddset(&dev->sigmask, SIGTTOU);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116 dev->sigdata.context = lock.context;
Dave Airlieb5e89ed2005-09-25 14:28:13 +1000117 dev->sigdata.lock = dev->lock.hw_lock;
118 block_all_signals(drm_notifier, &dev->sigdata, &dev->sigmask);
119
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120 if (dev->driver->dma_ready && (lock.flags & _DRM_LOCK_READY))
121 dev->driver->dma_ready(dev);
Dave Airlieb5e89ed2005-09-25 14:28:13 +1000122
Dave Airlied985c102006-01-02 21:32:48 +1100123 if (dev->driver->dma_quiescent && (lock.flags & _DRM_LOCK_QUIESCENT)) {
124 if (dev->driver->dma_quiescent(dev)) {
Dave Airliecf65f162005-11-24 21:41:14 +1100125 DRM_DEBUG("%d waiting for DMA quiescent\n", lock.context);
Dave Airlied985c102006-01-02 21:32:48 +1100126 return DRM_ERR(EBUSY);
127 }
128 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130 /* dev->driver->kernel_context_switch isn't used by any of the x86
131 * drivers but is used by the Sparc driver.
132 */
Dave Airlieb5e89ed2005-09-25 14:28:13 +1000133 if (dev->driver->kernel_context_switch &&
134 dev->last_context != lock.context) {
135 dev->driver->kernel_context_switch(dev, dev->last_context,
136 lock.context);
137 }
Dave Airlied985c102006-01-02 21:32:48 +1100138 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139}
140
Dave Airlieb5e89ed2005-09-25 14:28:13 +1000141/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 * 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 */
Dave Airlieb5e89ed2005-09-25 14:28:13 +1000152int drm_unlock(struct inode *inode, struct file *filp,
153 unsigned int cmd, unsigned long arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154{
155 drm_file_t *priv = filp->private_data;
156 drm_device_t *dev = priv->head->dev;
157 drm_lock_t lock;
Dave Airlie5c2df2b2006-10-24 11:36:59 -0700158 unsigned long irqflags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159
Dave Airlieb5e89ed2005-09-25 14:28:13 +1000160 if (copy_from_user(&lock, (drm_lock_t __user *) arg, sizeof(lock)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161 return -EFAULT;
162
Dave Airlieb5e89ed2005-09-25 14:28:13 +1000163 if (lock.context == DRM_KERNEL_CONTEXT) {
164 DRM_ERROR("Process %d using kernel context %d\n",
165 current->pid, lock.context);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166 return -EINVAL;
167 }
168
=?utf-8?q?Michel_D=C3=A4nzer?=2e54a002006-10-24 23:08:16 +1000169 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
Dave Airlieb5e89ed2005-09-25 14:28:13 +1000179 atomic_inc(&dev->counts[_DRM_STAT_UNLOCKS]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180
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 {
Dave Airlieb5e89ed2005-09-25 14:28:13 +1000187 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");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 }
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 */
209int drm_lock_take(__volatile__ unsigned int *lock, unsigned int context)
210{
211 unsigned int old, new, prev;
212
213 do {
214 old = *lock;
Dave Airlieb5e89ed2005-09-25 14:28:13 +1000215 if (old & _DRM_LOCK_HELD)
216 new = old | _DRM_LOCK_CONT;
217 else
218 new = context | _DRM_LOCK_HELD;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219 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)) {
Dave Airlieb5e89ed2005-09-25 14:28:13 +1000231 /* Have lock */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232 return 1;
233 }
234 return 0;
235}
236
237/**
238 * This takes a lock forcibly and hands it to context. Should ONLY be used
Dave Airlieb5e89ed2005-09-25 14:28:13 +1000239 * inside *_unlock to give lock to kernel before calling *_dma_schedule.
240 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241 * \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 */
Dave Airlieb5e89ed2005-09-25 14:28:13 +1000249static int drm_lock_transfer(drm_device_t * dev,
Dave Airliec94f7022005-07-07 21:03:38 +1000250 __volatile__ unsigned int *lock,
251 unsigned int context)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252{
253 unsigned int old, new, prev;
254
255 dev->lock.filp = NULL;
256 do {
Dave Airlieb5e89ed2005-09-25 14:28:13 +1000257 old = *lock;
258 new = context | _DRM_LOCK_HELD;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259 prev = cmpxchg(lock, old, new);
260 } while (prev != old);
261 return 1;
262}
263
264/**
265 * Free lock.
Dave Airlieb5e89ed2005-09-25 14:28:13 +1000266 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267 * \param dev DRM device.
268 * \param lock lock.
269 * \param context context.
Dave Airlieb5e89ed2005-09-25 14:28:13 +1000270 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 * 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 */
Dave Airlieb5e89ed2005-09-25 14:28:13 +1000275int drm_lock_free(drm_device_t * dev,
276 __volatile__ unsigned int *lock, unsigned int context)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277{
278 unsigned int old, new, prev;
279
280 dev->lock.filp = NULL;
281 do {
Dave Airlieb5e89ed2005-09-25 14:28:13 +1000282 old = *lock;
283 new = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284 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",
Dave Airlieb5e89ed2005-09-25 14:28:13 +1000288 context, _DRM_LOCKING_CONTEXT(old));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289 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 */
Dave Airliec94f7022005-07-07 21:03:38 +1000306static int drm_notifier(void *priv)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307{
Dave Airlieb5e89ed2005-09-25 14:28:13 +1000308 drm_sigdata_t *s = (drm_sigdata_t *) priv;
309 unsigned int old, new, prev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310
Dave Airlieb5e89ed2005-09-25 14:28:13 +1000311 /* Allow signal delivery if lock isn't held */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312 if (!s->lock || !_DRM_LOCK_IS_HELD(s->lock->lock)
Dave Airlieb5e89ed2005-09-25 14:28:13 +1000313 || _DRM_LOCKING_CONTEXT(s->lock->lock) != s->context)
314 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315
Dave Airlieb5e89ed2005-09-25 14:28:13 +1000316 /* Otherwise, set flag to force call to
317 drmUnlock */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318 do {
Dave Airlieb5e89ed2005-09-25 14:28:13 +1000319 old = s->lock->lock;
320 new = old | _DRM_LOCK_CONT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321 prev = cmpxchg(&s->lock->lock, old, new);
322 } while (prev != old);
323 return 0;
324}