2 * Copyright © 2008 Intel Corporation
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
24 * Eric Anholt <eric@anholt.net>
28 #include <linux/types.h>
29 #include <linux/slab.h>
31 #include <linux/uaccess.h>
33 #include <linux/file.h>
34 #include <linux/module.h>
35 #include <linux/mman.h>
36 #include <linux/pagemap.h>
41 * This file provides some of the base ioctls and library routines for
42 * the graphics memory manager implemented by each device driver.
44 * Because various devices have different requirements in terms of
45 * synchronization and migration strategies, implementing that is left up to
46 * the driver, and all that the general API provides should be generic --
47 * allocating objects, reading/writing data with the cpu, freeing objects.
48 * Even there, platform-dependent optimizations for reading/writing data with
49 * the CPU mean we'll likely hook those out to driver-specific calls. However,
50 * the DRI2 implementation wants to have at least allocate/mmap be generic.
52 * The goal was to have swap-backed object allocation managed through
53 * struct file. However, file descriptors as handles to a struct file have
55 * - Process limits prevent more than 1024 or so being used at a time by
57 * - Inability to allocate high fds will aggravate the X Server's select()
58 * handling, and likely that of many GL client applications as well.
60 * This led to a plan of using our own integer IDs (called handles, following
61 * DRM terminology) to mimic fds, and implement the fd syscalls we need as
62 * ioctls. The objects themselves will still include the struct file so
63 * that we can transition to fds if the required kernel infrastructure shows
64 * up at a later date, and as our interface with shmfs for memory allocation.
68 * Initialize the GEM device fields
72 drm_gem_init(struct drm_device *dev)
74 spin_lock_init(&dev->object_name_lock);
75 idr_init(&dev->object_name_idr);
76 atomic_set(&dev->object_count, 0);
77 atomic_set(&dev->object_memory, 0);
78 atomic_set(&dev->pin_count, 0);
79 atomic_set(&dev->pin_memory, 0);
80 atomic_set(&dev->gtt_count, 0);
81 atomic_set(&dev->gtt_memory, 0);
86 * Allocate a GEM object of the specified size with shmfs backing store
88 struct drm_gem_object *
89 drm_gem_object_alloc(struct drm_device *dev, size_t size)
91 struct drm_gem_object *obj;
93 BUG_ON((size & (PAGE_SIZE - 1)) != 0);
95 obj = kcalloc(1, sizeof(*obj), GFP_KERNEL);
98 obj->filp = shmem_file_setup("drm mm object", size, 0);
99 if (IS_ERR(obj->filp)) {
103 kref_init(&obj->refcount);
104 kref_init(&obj->handlecount);
106 if (dev->driver->gem_init_object != NULL &&
107 dev->driver->gem_init_object(obj) != 0) {
112 atomic_inc(&dev->object_count);
113 atomic_add(obj->size, &dev->object_memory);
116 EXPORT_SYMBOL(drm_gem_object_alloc);
119 * Removes the mapping from handle to filp for this object.
122 drm_gem_handle_delete(struct drm_file *filp, int handle)
124 struct drm_device *dev;
125 struct drm_gem_object *obj;
127 /* This is gross. The idr system doesn't let us try a delete and
128 * return an error code. It just spews if you fail at deleting.
129 * So, we have to grab a lock around finding the object and then
130 * doing the delete on it and dropping the refcount, or the user
131 * could race us to double-decrement the refcount and cause a
132 * use-after-free later. Given the frequency of our handle lookups,
133 * we may want to use ida for number allocation and a hash table
134 * for the pointers, anyway.
136 spin_lock(&filp->table_lock);
138 /* Check if we currently have a reference on the object */
139 obj = idr_find(&filp->object_idr, handle);
141 spin_unlock(&filp->table_lock);
146 /* Release reference and decrement refcount. */
147 idr_remove(&filp->object_idr, handle);
148 spin_unlock(&filp->table_lock);
150 mutex_lock(&dev->struct_mutex);
151 drm_gem_object_handle_unreference(obj);
152 mutex_unlock(&dev->struct_mutex);
158 * Create a handle for this object. This adds a handle reference
159 * to the object, which includes a regular reference count. Callers
160 * will likely want to dereference the object afterwards.
163 drm_gem_handle_create(struct drm_file *file_priv,
164 struct drm_gem_object *obj,
170 * Get the user-visible handle using idr.
173 /* ensure there is space available to allocate a handle */
174 if (idr_pre_get(&file_priv->object_idr, GFP_KERNEL) == 0)
177 /* do the allocation under our spinlock */
178 spin_lock(&file_priv->table_lock);
179 ret = idr_get_new_above(&file_priv->object_idr, obj, 1, handlep);
180 spin_unlock(&file_priv->table_lock);
187 drm_gem_object_handle_reference(obj);
190 EXPORT_SYMBOL(drm_gem_handle_create);
192 /** Returns a reference to the object named by the handle. */
193 struct drm_gem_object *
194 drm_gem_object_lookup(struct drm_device *dev, struct drm_file *filp,
197 struct drm_gem_object *obj;
199 spin_lock(&filp->table_lock);
201 /* Check if we currently have a reference on the object */
202 obj = idr_find(&filp->object_idr, handle);
204 spin_unlock(&filp->table_lock);
208 drm_gem_object_reference(obj);
210 spin_unlock(&filp->table_lock);
214 EXPORT_SYMBOL(drm_gem_object_lookup);
217 * Releases the handle to an mm object.
220 drm_gem_close_ioctl(struct drm_device *dev, void *data,
221 struct drm_file *file_priv)
223 struct drm_gem_close *args = data;
226 if (!(dev->driver->driver_features & DRIVER_GEM))
229 ret = drm_gem_handle_delete(file_priv, args->handle);
235 * Create a global name for an object, returning the name.
237 * Note that the name does not hold a reference; when the object
238 * is freed, the name goes away.
241 drm_gem_flink_ioctl(struct drm_device *dev, void *data,
242 struct drm_file *file_priv)
244 struct drm_gem_flink *args = data;
245 struct drm_gem_object *obj;
248 if (!(dev->driver->driver_features & DRIVER_GEM))
251 obj = drm_gem_object_lookup(dev, file_priv, args->handle);
256 if (idr_pre_get(&dev->object_name_idr, GFP_KERNEL) == 0)
259 spin_lock(&dev->object_name_lock);
261 spin_unlock(&dev->object_name_lock);
264 ret = idr_get_new_above(&dev->object_name_idr, obj, 1,
266 spin_unlock(&dev->object_name_lock);
271 mutex_lock(&dev->struct_mutex);
272 drm_gem_object_unreference(obj);
273 mutex_unlock(&dev->struct_mutex);
278 * Leave the reference from the lookup around as the
279 * name table now holds one
281 args->name = (uint64_t) obj->name;
287 * Open an object using the global name, returning a handle and the size.
289 * This handle (of course) holds a reference to the object, so the object
290 * will not go away until the handle is deleted.
293 drm_gem_open_ioctl(struct drm_device *dev, void *data,
294 struct drm_file *file_priv)
296 struct drm_gem_open *args = data;
297 struct drm_gem_object *obj;
301 if (!(dev->driver->driver_features & DRIVER_GEM))
304 spin_lock(&dev->object_name_lock);
305 obj = idr_find(&dev->object_name_idr, (int) args->name);
307 drm_gem_object_reference(obj);
308 spin_unlock(&dev->object_name_lock);
312 ret = drm_gem_handle_create(file_priv, obj, &handle);
313 mutex_lock(&dev->struct_mutex);
314 drm_gem_object_unreference(obj);
315 mutex_unlock(&dev->struct_mutex);
319 args->handle = handle;
320 args->size = obj->size;
326 * Called at device open time, sets up the structure for handling refcounting
330 drm_gem_open(struct drm_device *dev, struct drm_file *file_private)
332 idr_init(&file_private->object_idr);
333 spin_lock_init(&file_private->table_lock);
337 * Called at device close to release the file's
338 * handle references on objects.
341 drm_gem_object_release_handle(int id, void *ptr, void *data)
343 struct drm_gem_object *obj = ptr;
345 drm_gem_object_handle_unreference(obj);
351 * Called at close time when the filp is going away.
353 * Releases any remaining references on objects by this filp.
356 drm_gem_release(struct drm_device *dev, struct drm_file *file_private)
358 mutex_lock(&dev->struct_mutex);
359 idr_for_each(&file_private->object_idr,
360 &drm_gem_object_release_handle, NULL);
362 idr_destroy(&file_private->object_idr);
363 mutex_unlock(&dev->struct_mutex);
367 * Called after the last reference to the object has been lost.
372 drm_gem_object_free(struct kref *kref)
374 struct drm_gem_object *obj = (struct drm_gem_object *) kref;
375 struct drm_device *dev = obj->dev;
377 BUG_ON(!mutex_is_locked(&dev->struct_mutex));
379 if (dev->driver->gem_free_object != NULL)
380 dev->driver->gem_free_object(obj);
383 atomic_dec(&dev->object_count);
384 atomic_sub(obj->size, &dev->object_memory);
387 EXPORT_SYMBOL(drm_gem_object_free);
390 * Called after the last handle to the object has been closed
392 * Removes any name for the object. Note that this must be
393 * called before drm_gem_object_free or we'll be touching
397 drm_gem_object_handle_free(struct kref *kref)
399 struct drm_gem_object *obj = container_of(kref,
400 struct drm_gem_object,
402 struct drm_device *dev = obj->dev;
404 /* Remove any name for this object */
405 spin_lock(&dev->object_name_lock);
407 idr_remove(&dev->object_name_idr, obj->name);
408 spin_unlock(&dev->object_name_lock);
410 * The object name held a reference to this object, drop
413 drm_gem_object_unreference(obj);
415 spin_unlock(&dev->object_name_lock);
418 EXPORT_SYMBOL(drm_gem_object_handle_free);