1 files changed, 420 insertions, 0 deletions
diff --git a/linux-core/drm_gem.c b/linux-core/drm_gem.c
new file mode 100644
index 00000000..434155b3
--- /dev/null
+++ b/linux-core/drm_gem.c
@@ -0,0 +1,420 @@
+/*
+ * Copyright © 2008 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ * Authors:
+ *    Eric Anholt <eric@anholt.net>
+ *
+ */
+
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include <linux/uaccess.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/module.h>
+#include <linux/mman.h>
+#include <linux/pagemap.h>
+#include "drmP.h"
+
+/** @file drm_gem.c
+ *
+ * This file provides some of the base ioctls and library routines for
+ * the graphics memory manager implemented by each device driver.
+ *
+ * Because various devices have different requirements in terms of
+ * synchronization and migration strategies, implementing that is left up to
+ * the driver, and all that the general API provides should be generic --
+ * allocating objects, reading/writing data with the cpu, freeing objects.
+ * Even there, platform-dependent optimizations for reading/writing data with
+ * the CPU mean we'll likely hook those out to driver-specific calls.  However,
+ * the DRI2 implementation wants to have at least allocate/mmap be generic.
+ *
+ * The goal was to have swap-backed object allocation managed through
+ * struct file.  However, file descriptors as handles to a struct file have
+ * two major failings:
+ * - Process limits prevent more than 1024 or so being used at a time by
+ *   default.
+ * - Inability to allocate high fds will aggravate the X Server's select()
+ *   handling, and likely that of many GL client applications as well.
+ *
+ * This led to a plan of using our own integer IDs (called handles, following
+ * DRM terminology) to mimic fds, and implement the fd syscalls we need as
+ * ioctls.  The objects themselves will still include the struct file so
+ * that we can transition to fds if the required kernel infrastructure shows
+ * up at a later date, and as our interface with shmfs for memory allocation.
+ */
+
+/**
+ * Initialize the GEM device fields
+ */
+
+int
+drm_gem_init(struct drm_device *dev)
+{
+	spin_lock_init(&dev->object_name_lock);
+	idr_init(&dev->object_name_idr);
+	atomic_set(&dev->object_count, 0);
+	atomic_set(&dev->object_memory, 0);
+	atomic_set(&dev->pin_count, 0);
+	atomic_set(&dev->pin_memory, 0);
+	atomic_set(&dev->gtt_count, 0);
+	atomic_set(&dev->gtt_memory, 0);
+	return 0;
+}
+
+/**
+ * Allocate a GEM object of the specified size with shmfs backing store
+ */
+struct drm_gem_object *
+drm_gem_object_alloc(struct drm_device *dev, size_t size)
+{
+	struct drm_gem_object *obj;
+
+	BUG_ON((size & (PAGE_SIZE - 1)) != 0);
+
+	obj = kcalloc(1, sizeof(*obj), GFP_KERNEL);
+
+	obj->dev = dev;
+	obj->filp = shmem_file_setup("drm mm object", size, 0);
+	if (IS_ERR(obj->filp)) {
+		kfree(obj);
+		return NULL;
+	}
+
+	kref_init(&obj->refcount);
+	kref_init(&obj->handlecount);
+	obj->size = size;
+	if (dev->driver->gem_init_object != NULL &&
+	    dev->driver->gem_init_object(obj) != 0) {
+		fput(obj->filp);
+		kfree(obj);
+		return NULL;
+	}
+	atomic_inc(&dev->object_count);
+	atomic_add(obj->size, &dev->object_memory);
+	return obj;
+}
+EXPORT_SYMBOL(drm_gem_object_alloc);
+
+/**
+ * Removes the mapping from handle to filp for this object.
+ */
+static int
+drm_gem_handle_delete(struct drm_file *filp, int handle)
+{
+	struct drm_device *dev;
+	struct drm_gem_object *obj;
+
+	/* This is gross. The idr system doesn't let us try a delete and
+	 * return an error code.  It just spews if you fail at deleting.
+	 * So, we have to grab a lock around finding the object and then
+	 * doing the delete on it and dropping the refcount, or the user
+	 * could race us to double-decrement the refcount and cause a
+	 * use-after-free later.  Given the frequency of our handle lookups,
+	 * we may want to use ida for number allocation and a hash table
+	 * for the pointers, anyway.
+	 */
+	spin_lock(&filp->table_lock);
+
+	/* Check if we currently have a reference on the object */
+	obj = idr_find(&filp->object_idr, handle);
+	if (obj == NULL) {
+		spin_unlock(&filp->table_lock);
+		return -EINVAL;
+	}
+	dev = obj->dev;
+
+	/* Release reference and decrement refcount. */
+	idr_remove(&filp->object_idr, handle);
+	spin_unlock(&filp->table_lock);
+
+	mutex_lock(&dev->struct_mutex);
+	drm_gem_object_handle_unreference(obj);
+	mutex_unlock(&dev->struct_mutex);
+
+	return 0;
+}
+
+/**
+ * Create a handle for this object. This adds a handle reference
+ * to the object, which includes a regular reference count. Callers
+ * will likely want to dereference the object afterwards.
+ */
+int
+drm_gem_handle_create(struct drm_file *file_priv,
+		       struct drm_gem_object *obj,
+		       int *handlep)
+{
+	int	ret;
+
+	/*
+	 * Get the user-visible handle using idr.
+	 */
+again:
+	/* ensure there is space available to allocate a handle */
+	if (idr_pre_get(&file_priv->object_idr, GFP_KERNEL) == 0)
+		return -ENOMEM;
+
+	/* do the allocation under our spinlock */
+	spin_lock(&file_priv->table_lock);
+	ret = idr_get_new_above(&file_priv->object_idr, obj, 1, handlep);
+	spin_unlock(&file_priv->table_lock);
+	if (ret == -EAGAIN)
+		goto again;
+
+	if (ret != 0)
+		return ret;
+
+	drm_gem_object_handle_reference(obj);
+	return 0;
+}
+EXPORT_SYMBOL(drm_gem_handle_create);
+
+/** Returns a reference to the object named by the handle. */
+struct drm_gem_object *
+drm_gem_object_lookup(struct drm_device *dev, struct drm_file *filp,
+		      int handle)
+{
+	struct drm_gem_object *obj;
+
+	spin_lock(&filp->table_lock);
+
+	/* Check if we currently have a reference on the object */
+	obj = idr_find(&filp->object_idr, handle);
+	if (obj == NULL) {
+		spin_unlock(&filp->table_lock);
+		return NULL;
+	}
+
+	drm_gem_object_reference(obj);
+
+	spin_unlock(&filp->table_lock);
+
+	return obj;
+}
+EXPORT_SYMBOL(drm_gem_object_lookup);
+
+/**
+ * Releases the handle to an mm object.
+ */
+int
+drm_gem_close_ioctl(struct drm_device *dev, void *data,
+		    struct drm_file *file_priv)
+{
+	struct drm_gem_close *args = data;
+	int ret;
+
+	if (!(dev->driver->driver_features & DRIVER_GEM))
+		return -ENODEV;
+
+	ret = drm_gem_handle_delete(file_priv, args->handle);
+
+	return ret;
+}
+
+/**
+ * Create a global name for an object, returning the name.
+ *
+ * Note that the name does not hold a reference; when the object
+ * is freed, the name goes away.
+ */
+int
+drm_gem_flink_ioctl(struct drm_device *dev, void *data,
+		    struct drm_file *file_priv)
+{
+	struct drm_gem_flink *args = data;
+	struct drm_gem_object *obj;
+	int ret;
+
+	if (!(dev->driver->driver_features & DRIVER_GEM))
+		return -ENODEV;
+
+	obj = drm_gem_object_lookup(dev, file_priv, args->handle);
+	if (obj == NULL)
+		return -EINVAL;
+
+again:
+	if (idr_pre_get(&dev->object_name_idr, GFP_KERNEL) == 0)
+		return -ENOMEM;
+
+	spin_lock(&dev->object_name_lock);
+	if (obj->name) {
+		spin_unlock(&dev->object_name_lock);
+		return -EEXIST;
+	}
+	ret = idr_get_new_above(&dev->object_name_idr, obj, 1,
+				 &obj->name);
+	spin_unlock(&dev->object_name_lock);
+	if (ret == -EAGAIN)
+		goto again;
+
+	if (ret != 0) {
+		mutex_lock(&dev->struct_mutex);
+		drm_gem_object_unreference(obj);
+		mutex_unlock(&dev->struct_mutex);
+		return ret;
+	}
+
+	/*
+	 * Leave the reference from the lookup around as the
+	 * name table now holds one
+	 */
+	args->name = (uint64_t) obj->name;
+
+	return 0;
+}
+
+/**
+ * Open an object using the global name, returning a handle and the size.
+ *
+ * This handle (of course) holds a reference to the object, so the object
+ * will not go away until the handle is deleted.
+ */
+int
+drm_gem_open_ioctl(struct drm_device *dev, void *data,
+		   struct drm_file *file_priv)
+{
+	struct drm_gem_open *args = data;
+	struct drm_gem_object *obj;
+	int ret;
+	int handle;
+
+	if (!(dev->driver->driver_features & DRIVER_GEM))
+		return -ENODEV;
+
+	spin_lock(&dev->object_name_lock);
+	obj = idr_find(&dev->object_name_idr, (int) args->name);
+	if (obj)
+		drm_gem_object_reference(obj);
+	spin_unlock(&dev->object_name_lock);
+	if (!obj)
+		return -ENOENT;
+
+	ret = drm_gem_handle_create(file_priv, obj, &handle);
+	mutex_lock(&dev->struct_mutex);
+	drm_gem_object_unreference(obj);
+	mutex_unlock(&dev->struct_mutex);
+	if (ret)
+		return ret;
+
+	args->handle = handle;
+	args->size = obj->size;
+
+	return 0;
+}
+
+/**
+ * Called at device open time, sets up the structure for handling refcounting
+ * of mm objects.
+ */
+void
+drm_gem_open(struct drm_device *dev, struct drm_file *file_private)
+{
+	idr_init(&file_private->object_idr);
+	spin_lock_init(&file_private->table_lock);
+}
+
+/**
+ * Called at device close to release the file's
+ * handle references on objects.
+ */
+static int
+drm_gem_object_release_handle(int id, void *ptr, void *data)
+{
+	struct drm_gem_object *obj = ptr;
+
+	drm_gem_object_handle_unreference(obj);
+
+	return 0;
+}
+
+/**
+ * Called at close time when the filp is going away.
+ *
+ * Releases any remaining references on objects by this filp.
+ */
+void
+drm_gem_release(struct drm_device *dev, struct drm_file *file_private)
+{
+	mutex_lock(&dev->struct_mutex);
+	idr_for_each(&file_private->object_idr,
+		     &drm_gem_object_release_handle, NULL);
+
+	idr_destroy(&file_private->object_idr);
+	mutex_unlock(&dev->struct_mutex);
+}
+
+/**
+ * Called after the last reference to the object has been lost.
+ *
+ * Frees the object
+ */
+void
+drm_gem_object_free(struct kref *kref)
+{
+	struct drm_gem_object *obj = (struct drm_gem_object *) kref;
+	struct drm_device *dev = obj->dev;
+
+	BUG_ON(!mutex_is_locked(&dev->struct_mutex));
+
+	if (dev->driver->gem_free_object != NULL)
+		dev->driver->gem_free_object(obj);
+
+	fput(obj->filp);
+	atomic_dec(&dev->object_count);
+	atomic_sub(obj->size, &dev->object_memory);
+	kfree(obj);
+}
+EXPORT_SYMBOL(drm_gem_object_free);
+
+/**
+ * Called after the last handle to the object has been closed
+ *
+ * Removes any name for the object. Note that this must be
+ * called before drm_gem_object_free or we'll be touching
+ * freed memory
+ */
+void
+drm_gem_object_handle_free(struct kref *kref)
+{
+	struct drm_gem_object *obj = container_of(kref,
+						  struct drm_gem_object,
+						  handlecount);
+	struct drm_device *dev = obj->dev;
+
+	/* Remove any name for this object */
+	spin_lock(&dev->object_name_lock);
+	if (obj->name) {
+		idr_remove(&dev->object_name_idr, obj->name);
+		spin_unlock(&dev->object_name_lock);
+		/*
+		 * The object name held a reference to this object, drop
+		 * that now.
+		 */
+		drm_gem_object_unreference(obj);
+	} else
+		spin_unlock(&dev->object_name_lock);
+
+}
+EXPORT_SYMBOL(drm_gem_object_handle_free);
+