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/*
* 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.
*/
/*
* We make up offsets for buffer objects so we can recognize them at
* mmap time.
*/
#define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFFUL >> PAGE_SHIFT) + 1)
#define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFFUL >> PAGE_SHIFT) * 16)
/**
* Initialize the GEM device fields
*/
int
drm_gem_init(struct drm_device *dev)
{
struct drm_gem_mm *mm;
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);
mm = drm_calloc(1, sizeof(struct drm_gem_mm), DRM_MEM_MM);
if (!mm) {
DRM_ERROR("out of memory\n");
return -ENOMEM;
}
dev->mm_private = mm;
if (drm_ht_create(&mm->offset_hash, 19)) {
drm_free(mm, sizeof(struct drm_gem_mm), DRM_MEM_MM);
return -ENOMEM;
}
if (drm_mm_init(&mm->offset_manager, DRM_FILE_PAGE_OFFSET_START,
DRM_FILE_PAGE_OFFSET_SIZE)) {
drm_free(mm, sizeof(struct drm_gem_mm), DRM_MEM_MM);
drm_ht_remove(&mm->offset_hash);
return -ENOMEM;
}
return 0;
}
void
drm_gem_destroy(struct drm_device *dev)
{
struct drm_gem_mm *mm = dev->mm_private;
drm_mm_takedown(&mm->offset_manager);
drm_ht_remove(&mm->offset_hash);
drm_free(mm, sizeof(struct drm_gem_mm), DRM_MEM_MM);
dev->mm_private = NULL;
}
/**
* 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, VM_NORESERVE);
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 -EBADF;
again:
if (idr_pre_get(&dev->object_name_idr, GFP_KERNEL) == 0)
return -ENOMEM;
spin_lock(&dev->object_name_lock);
if<
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