- 根目录:
- drivers
- gpu
- drm
- drm_gem.c
/*
* 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 <linux/shmem_fs.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.
*/
/* pgoff in mmap is an unsigned long, so we need to make sure that
* the faked up offset will fit
*/
#if BITS_PER_LONG == 64
#define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFFUL >> PAGE_SHIFT) + 1)
#define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFFUL >> PAGE_SHIFT) * 16)
#else
#define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFUL >> PAGE_SHIFT) + 1)
#define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFUL >> PAGE_SHIFT) * 16)
#endif
/**
* 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);
mm = kzalloc(sizeof(struct drm_gem_mm), GFP_KERNEL);
if (!mm) {
DRM_ERROR("out of memory\n");
return -ENOMEM;
}
dev->mm_private = mm;
if (drm_ht_create(&mm->offset_hash, 12)) {
kfree(mm);
return -ENOMEM;
}
if (drm_mm_init(&mm->offset_manager, DRM_FILE_PAGE_OFFSET_START,
DRM_FILE_PAGE_OFFSET_SIZE)) {
drm_ht_remove(&mm->offset_hash);
kfree(mm);
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);
kfree(mm);
dev->mm_private = NULL;
}
/**
* Initialize an already allocate GEM object of the specified size with
* shmfs backing store.
*/
int drm_gem_object_init(struct drm_device *dev,
struct drm_gem_object *obj, size_t size)
{
BUG_ON((size & (PAGE_SIZE - 1)) != 0);
obj->dev = dev;
obj->filp = shmem_file_setup("drm mm object", size, VM_NORESERVE);
if (IS_ERR(obj->filp))
return -ENOMEM;
kref_init(&obj->refcount);
atomic_set(&obj->handle_count, 0);
obj->size = size;
return 0;
}
EXPORT_SYMBOL(drm_gem_object_init);
/**
* 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;
obj = kzalloc(sizeof(*obj), GFP_KERNEL);
if (!obj)
goto free;
if (drm_gem_object_init(dev, obj, size) != 0)
goto free;
if (dev->driver->gem_init_object != NULL &&
dev->driver->gem_init_object(obj) != 0) {
goto fput;
}
return obj;
fput:
/* Object_init mangles the global counters - readjust them. */
fput(obj->filp);
free:
kfree(obj);
return NULL;
}
EXPORT_SYMBOL(drm_gem_object_alloc);
/**
* Removes the mapping from handle to filp for this object.
*/
int
drm_gem_handle_delete(struct drm_file *filp, u32 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);
drm_gem_object_handle_unreference_unlocked(obj);
return 0;
}
EXPORT_SYMBOL(drm_gem_handle_delete);
/**
* 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,
u32 *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, (int *)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,
u32 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 -ENOENT;
again:
if (idr_pre_get(&dev->object_name_idr, GFP_KERNEL) == 0) {
ret = -ENOMEM;
goto err;
}
spin_lock(&dev->object_name_lock);
if (!obj->name) {
ret = idr_get_new_above(&dev->object_name_idr, obj, 1,
&obj->name);
args->name = (uint64_t) obj->name;
spin_unlock(&dev->object_name_lock);
if (ret == -EAGAIN)
goto again;
if (ret != 0)
goto err;
/* Allocate a reference for the name table. */
drm_gem_object_reference(obj);
} else {
args->name = (uint64_t) obj->name;
spin_unlock(&dev->object_name_lock);
ret = 0;
}
err:
drm_gem_object_unreference_unlocked(obj);
return ret;
}
/**
* 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;
u32 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);
drm_gem_object_unreference_unlocked(obj);
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_unlocked(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)
{
idr_for_each(&file_private->object_idr,
&drm_gem_object_release_handle, NULL);
idr_remove_all(&file_private->object_idr);
idr_destroy(&file_private->object_idr);
}
void
drm_gem_object_release(struct drm_gem_object *obj)
{
fput(obj->filp);
}
EXPORT_SYMBOL(drm_gem_object_release);
/**
* Called after the last reference to the object has been lost.
* Must be called holding struct_ mutex
*
* 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);
}
EXPORT_SYMBOL(drm_gem_object_free);
static void drm_gem_object_ref_bug(struct kref *list_kref)
{
BUG();
}
/**
* 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 drm_gem_object *obj)
{
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);
obj->name = 0;
spin_unlock(&dev->object_name_lock);
/*
* The object name held a reference to this object, drop
* that now.
*
* This cannot be the last reference, since the handle holds one too.
*/
kref_put(&obj->refcount, drm_gem_object_ref_bug);
} else
spin_unlock(&dev->object_name_lock);
}
EXPORT_SYMBOL(drm_gem_object_handle_free);
void drm_gem_vm_open(struct vm_area_struct *vma)
{
struct drm_gem_object *obj = vma->vm_private_data;
drm_gem_object_reference(obj);
mutex_lock(&obj->dev->struct_mutex);
drm_vm_open_locked(vma);
mutex_unlock(&obj->dev->struct_mutex);
}
EXPORT_SYMBOL(drm_gem_vm_open);
void drm_gem_vm_close(struct vm_area_struct *vma)
{
struct drm_gem_object *obj = vma->vm_private_data;
struct drm_device *dev = obj->dev;
mutex_lock(&dev->struct_mutex);
drm_vm_close_locked(vma);
drm_gem_object_unreference(obj);
mutex_unlock(&dev->struct_mutex);
}
EXPORT_SYMBOL(drm_gem_vm_close);
/**
* drm_gem_mmap - memory map routine for GEM objects
* @filp: DRM file pointer
* @vma: VMA for the area to be mapped
*
* If a driver supports GEM object mapping, mmap calls on the DRM file
* descriptor will end up here.
*
* If we find the object based on the offset passed in (vma->vm_pgoff will
* contain the fake offset we created when the GTT map ioctl was called on
* the object), we set up the driver fault handler so that any accesses
* to the object can be trapped, to perform migration, GTT binding, surface
* register allocation, or performance monitoring.
*/
int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
{
struct drm_file *priv = filp->private_data;
struct drm_device *dev = priv->minor->dev;
struct drm_gem_mm *mm = dev->mm_private;
struct drm_local_map *map = NULL;
struct drm_gem_object *obj;
struct drm_hash_item *hash;
int ret = 0;
mutex_lock(&dev->struct_mutex);
if (drm_ht_find_item(&mm->offset_hash, vma->vm_pgoff, &hash)) {
mutex_unlock(&dev->struct_mutex);
return drm_mmap(filp, vma);
}
map = drm_hash_entry(hash, struct drm_map_list, hash)->map;
if (!map ||
((map->flags & _DRM_RESTRICTED) && !capable(CAP_SYS_ADMIN))) {
ret = -EPERM;
goto out_unlock;
}
/* Check for valid size. */
if (map->size < vma->vm_end - vma->vm_start) {
ret = -EINVAL;
goto out_unlock;
}
obj = map->handle;
if (!obj->dev->driver->gem_vm_ops) {
ret = -EINVAL;
goto out_unlock;
}
vma->vm_flags |= VM_RESERVED | VM_IO | VM_PFNMAP | VM_DONTEXPAND;
vma->vm_ops = obj->dev->driver->gem_vm_ops;
vma->vm_private_data = map->handle;
vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
/* Take a ref for this mapping of the object, so that the fault
* handler can dereference the mmap offset's pointer to the object.
* This reference is cleaned up by the corresponding vm_close
* (which should happen whether the vma was created by this call, or
* by a vm_open due to mremap or partial unmap or whatever).
*/
drm_gem_object_reference(obj);
vma->vm_file = filp; /* Needed for drm_vm_open() */
drm_vm_open_locked(vma);
out_unlock:
mutex_unlock(&dev->struct_mutex);
return ret;
}
EXPORT_SYMBOL(drm_gem_mmap);