- 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 <linux/dma-buf.h>
#include <drm/drmP.h>
#include <drm/drm_vma_manager.h>
#include <drm/drm_gem.h>
#include "drm_internal.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
/**
* drm_gem_init - Initialize the GEM device fields
* @dev: drm_devic structure to initialize
*/
int
drm_gem_init(struct drm_device *dev)
{
struct drm_vma_offset_manager *vma_offset_manager;
mutex_init(&dev->object_name_lock);
idr_init(&dev->object_name_idr);
vma_offset_manager = kzalloc(sizeof(*vma_offset_manager), GFP_KERNEL);
if (!vma_offset_manager) {
DRM_ERROR("out of memory\n");
return -ENOMEM;
}
dev->vma_offset_manager = vma_offset_manager;
drm_vma_offset_manager_init(vma_offset_manager,
DRM_FILE_PAGE_OFFSET_START,
DRM_FILE_PAGE_OFFSET_SIZE);
return 0;
}
void
drm_gem_destroy(struct drm_device *dev)
{
drm_vma_offset_manager_destroy(dev->vma_offset_manager);
kfree(dev->vma_offset_manager);
dev->vma_offset_manager = NULL;
}
/**
* drm_gem_object_init - initialize an allocated shmem-backed GEM object
* @dev: drm_device the object should be initialized for
* @obj: drm_gem_object to initialize
* @size: object size
*
* Initialize an already allocated 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)
{
struct file *filp;
drm_gem_private_object_init(dev, obj, size);
filp = shmem_file_setup("drm mm object", size, VM_NORESERVE);
if (IS_ERR(filp))
return PTR_ERR(filp);
obj->filp = filp;
return 0;
}
EXPORT_SYMBOL(drm_gem_object_init);
/**
* drm_gem_private_object_init - initialize an allocated private GEM object
* @dev: drm_device the object should be initialized for
* @obj: drm_gem_object to initialize
* @size: object size
*
* Initialize an already allocated GEM object of the specified size with
* no GEM provided backing store. Instead the caller is responsible for
* backing the object and handling it.
*/
void drm_gem_private_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 = NULL;
kref_init(&obj->refcount);
obj->handle_count = 0;
obj->size = size;
drm_vma_node_reset(&obj->vma_node);
}
EXPORT_SYMBOL(drm_gem_private_object_init);
static void
drm_gem_remove_prime_handles(struct drm_gem_object *obj, struct drm_file *filp)
{
/*
* Note: obj->dma_buf can't disappear as long as we still hold a
* handle reference in obj->handle_count.
*/
mutex_lock(&filp->prime.lock);
if (obj->dma_buf) {
drm_prime_remove_buf_handle_locked(&filp->prime,
obj->dma_buf);
}
mutex_unlock(&filp->prime.lock);
}
/**
* drm_gem_object_free - release resources bound to userspace handles
* @obj: GEM object to clean up.
*
* 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
*/
static void drm_gem_object_handle_free(struct drm_gem_object *obj)
{
struct drm_device *dev = obj->dev;
/* Remove any name for this object */
if (obj->name) {
idr_remove(&dev->object_name_idr, obj->name);
obj->name = 0;
}
}
static void drm_gem_object_exported_dma_buf_free(struct drm_gem_object *obj)
{
/* Unbreak the reference cycle if we have an exported dma_buf. */
if (obj->dma_buf) {
dma_buf_put(obj->dma_buf);
obj->dma_buf = NULL;
}
}
static void
drm_gem_object_handle_unreference_unlocked(struct drm_gem_object *obj)
{
if (WARN_ON(obj->handle_count == 0))
return;
/*
* Must bump handle count first as this may be the last
* ref, in which case the object would disappear before we
* checked for a name
*/
mutex_lock(&obj->dev->object_name_lock);
if (--obj->handle_count == 0) {
drm_gem_object_handle_free(obj);
drm_gem_object_exported_dma_buf_free(obj);
}
mutex_unlock(&obj->dev->object_name_lock);
drm_gem_object_unreference_unlocked(obj);
}
/**
* drm_gem_handle_delete - deletes the given file-private handle
* @filp: drm file-private structure to use for the handle look up
* @handle: userspace handle to delete
*
* Removes the GEM handle from the @filp lookup table and if this is the last
* handle also cleans up linked resources like GEM names.
*/
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);
if (drm_core_check_feature(dev, DRIVER_PRIME))
drm_gem_remove_prime_handles(obj, filp);
drm_vma_node_revoke(&obj->vma_node, filp->filp);
if (dev->driver->gem_close_object)
dev->driver->gem_close_object(obj, filp);
drm_gem_object_handle_unreference_unlocked(obj);
return 0;
}
EXPORT_SYMBOL(drm_gem_handle_delete);
/**
* drm_gem_dumb_destroy - dumb fb callback helper for gem based drivers
* @file: drm file-private structure to remove the dumb handle from
* @dev: corresponding drm_device
* @handle: the dumb handle to remove
*
* This implements the ->dumb_destroy kms driver callback for drivers which use
* gem to manage their backing storage.
*/
int drm_gem_dumb_destroy(struct drm_file *file,
struct drm_device *dev,
uint32_t handle)
{
return drm_gem_handle_delete(file, handle);
}
EXPORT_SYMBOL(drm_gem_dumb_destroy);
/**
* drm_gem_handle_create_tail - internal functions to create a handle
* @file_priv: drm file-private structure to register the handle for
* @obj: object to register
* @handlep: pionter to return the created handle to the caller
*
* This expects the dev->object_name_lock to be held already and will drop it
* before returning. Used to avoid races in establishing new handles when
* importing an object from either an flink name or a dma-buf.
*/
int
drm_gem_handle_create_tail(struct drm_file *file_priv,
struct drm_gem_object *obj,
u32 *handlep)
{
struct drm_device *dev = obj->dev;
int ret;
WARN_ON(!mutex_is_locked(&dev->object_name_lock));
/*
* Get the user-visible handle using idr. Preload and perform
* allocation under our spinlock.
*/
idr_preload(GFP_KERNEL);
spin_lock(&file_priv->table_lock);
ret = idr_alloc(&file_priv->object_idr, obj, 1, 0, GFP_NOWAIT);
drm_gem_object_reference(obj);
obj->handle_count++;
spin_unlock(&file_priv->table_lock);
idr_preload_end();
mutex_unlock(&dev->object_name_lock);
if (ret < 0) {
drm_gem_object_handle_unreference_unlocked(obj);
return ret;
}
*handlep = ret;
ret = drm_vma_node_allow(&obj->vma_node, file_priv->filp);
if (ret) {
drm_gem_handle_delete(file_priv, *handlep);
return ret;
}
if (dev->driver->gem_open_object) {
ret = dev->driver->gem_open_object(obj, file_priv);
if (ret) {
drm_gem_handle_delete(file_priv, *handlep);
return ret;
}
}
return 0;
}
/**
* gem_handle_create - create a gem handle for an object
* @file_priv: drm file-private structure to register the handle for
* @obj: object to register
* @handlep: pionter to return the created handle to the caller
*
* 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)
{
mutex_lock(&obj->dev->object_name_lock);
return drm_gem_handle_create_tail(file_priv, obj, handlep);
}
EXPORT_SYMBOL(drm_gem_handle_create);
/**
* drm_gem_free_mmap_offset - release a fake mmap offset for an object
* @obj: obj in question
*
* This routine frees fake offsets allocated by drm_gem_create_mmap_offset().
*/
void
drm_gem_free_mmap_offset(struct drm_gem_object *obj)
{
struct drm_device *dev = obj->dev;
drm_vma_offset_remove(dev->vma_offset_manager, &obj->vma_node);
}
EXPORT_SYMBOL(drm_gem_free_mmap_offset);
/**
* drm_gem_create_mmap_offset_size - create a fake mmap offset for an object
* @obj: obj in question
* @size: the virtual size
*
* GEM memory mapping works by handing back to userspace a fake mmap offset
* it can use in a subsequent mmap(2) call. The DRM core code then looks
* up the object based on the offset and sets up the various memory mapping
* structures.
*
* This routine allocates and attaches a fake offset for @obj, in cases where
* the virtual size differs from the physical size (ie. obj->size). Otherwise
* just use drm_gem_create_mmap_offset().
*/
int
drm_gem_create_mmap_offset_size(struct drm_gem_object *obj, size_t size)
{
struct drm_device *dev = obj->dev;
return drm_vma_offset_add(dev->vma_offset_manager, &obj->vma_node,
size / PAGE_SIZE);
}
EXPORT_SYMBOL(drm_gem_create_mmap_offset_size);
/**
* drm_gem_create_mmap_offset - create a fake mmap offset for an object
* @obj: obj in question
*
* GEM memory mapping works by handing back to userspace a fake mmap offset
* it can use in a subsequent mmap(2) call. The DRM core code then looks
* up the object based on the offset and sets up the various memory mapping
* structures.
*
* This routine allocates and attaches a fake offset for @obj.
*/
int drm_gem_create_mmap_offset(struct drm_gem_object *obj)
{
return drm_gem_create_mmap_offset_size(obj, obj->size);
}
EXPORT_SYMBOL(drm_gem_create_mmap_offset);
/**
* drm_gem_get_pages - helper to allocate backing pages for a GEM object
* from shmem
* @obj: obj in question
*
* This reads the page-array of the shmem-backing storage of the given gem
* object. An array of pages is returned. If a page is not allocated or
* swapped-out, this will allocate/swap-in the required pages. Note that the
* whole object is covered by the page-array and pinned in memory.
*
* Use drm_gem_put_pages() to release the array and unpin all pages.
*
* This uses the GFP-mask set on the shmem-mapping (see mapping_set_gfp_mask()).
* If you require other GFP-masks, you have to do those allocations yourself.
*
* Note that you are not allowed to change gfp-zones during runtime. That is,
* shmem_read_mapping_page_gfp() must be called with the same gfp_zone(gfp) as
* set during initialization. If you have special zone constraints, set them
* after drm_gem_init_object() via mapping_set_gfp_mask(). shmem-core takes care
* to keep pages in the required zone during swap-in.
*/
struct page **drm_gem_get_pages(struct drm_gem_object *obj)
{
struct address_space *mapping;
struct page *p, **pages;
int i, npages;
/* This is the shared memory object that backs the GEM resource */
mapping = file_inode(obj->filp)->i_mapping;
/* We already BUG_ON() for non-page-aligned sizes in
* drm_gem_object_init(), so we should never hit this unless
* driver author is doing something really wrong:
*/
WARN_ON((obj->size & (PAGE_SIZE - 1)) != 0);
npages = obj->size >> PAGE_SHIFT;
pages = drm_malloc_ab(npages, sizeof(struct page *));
if (pages == NULL)
return ERR_PTR(-ENOMEM);
for (i = 0; i < npages; i++) {
p = shmem_read_mapping_page(mapping, i);
if (IS_ERR(p))
goto fail;
pages[i] = p;
/* Make sure shmem keeps __GFP_DMA32 allocated pages in the
* correct region during swapin. Note that this requires
* __GFP_DMA32 to be set in mapping_gfp_mask(inode->i_mapping)
* so shmem can relocate pages during swapin if required.
*/
BUG_ON((mapping_gfp_mask(mapping) & __GFP_DMA32) &&
(page_to_pfn(p) >= 0x00100000UL));
}
return pages;
fail:
while (i--)
page_cache_release(pages[i]);
drm_free_large(pages);
return ERR_CAST(p);
}
EXPORT_SYMBOL(drm_gem_get_pages);
/**
* drm_gem_put_pages - helper to free backing pages for a GEM object
* @obj: obj in question
* @pages: pages to free
* @dirty: if true, pages will be marked as dirty
* @accessed: if true, the pages will be marked as accessed
*/
void drm_gem_put_pages(struct drm_gem_object *obj, struct page **pages,
bool dirty, bool accessed)
{
int i, npages;
/* We already BUG_ON() for non-page-aligned sizes in
* drm_gem_object_init(), so we should never hit this unless
* driver author is doing something really wrong:
*/
WARN_ON((obj->size & (PAGE_SIZE - 1)) != 0);
npages = obj->size >> PAGE_SHIFT;
for (i = 0; i < npages; i++) {
if (dirty)
set_page_dirty(pages[i]);
if (accessed)
mark_page_accessed(pages[i]);
/* Undo the reference we took when populating the table */
page_cache_release(pages[i]);
}
drm_free_large(pages);
}
EXPORT_SYMBOL(drm_gem_put_pages);
/** 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);
/**
* drm_gem_close_ioctl - implementation of the GEM_CLOSE ioctl
* @dev: drm_device
* @data: ioctl data
* @file_priv: drm file-private structure
*
* 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 (!drm_core_check_feature(dev, DRIVER_GEM))
return -ENODEV;
ret = drm_gem_handle_delete(file_priv, args->handle);
return ret;
}
/**
* drm_gem_flink_ioctl - implementation of the GEM_FLINK ioctl
* @dev: drm_device
* @data: ioctl data
* @file_priv: drm file-private structure
*
* 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 (!drm_core_check_feature(dev, DRIVER_GEM))
return -ENODEV;
obj = drm_gem_object_lookup(dev, file_priv, args->handle);
if (obj == NULL)
return -ENOENT;
mutex_lock(&dev->object_name_lock);
idr_preload(GFP_KERNEL);
/* prevent races with concurrent gem_close. */
if (obj->handle_count == 0) {
ret = -ENOENT;
goto err;
}
if (!obj->name) {
ret = idr_alloc(&dev->object_name_idr, obj, 1, 0, GFP_NOWAIT);
if (ret < 0)
goto err;
obj->name = ret;
}
args->name = (uint64_t) obj->name;
ret = 0;
err:
idr_preload_end();
mutex_unlock(&dev->object_name_lock);
drm_gem_object_unreference_unlocked(obj);
return ret;
}
/**
* drm_gem_open - implementation of the GEM_OPEN ioctl
* @dev: drm_device
* @data: ioctl data
* @file_priv: drm file-private structure
*
* 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 (!drm_core_check_feature(dev, DRIVER_GEM))
return -ENODEV;
mutex_lock(&dev->object_name_lock);
obj = idr_find(&dev->object_name_idr, (int) args->name);
if (obj) {
drm_gem_object_reference(obj);
} else {
mutex_unlock(&dev->object_name_lock);
return -ENOENT;
}
/* drm_gem_handle_create_tail unlocks dev->object_name_lock. */
ret = drm_gem_handle_create_tail(file_priv, obj, &handle);
drm_gem_object_unreference_unlocked(obj);
if (ret)
return ret;
args->handle = handle;
args->size = obj->size;
return 0;
}
/**
* gem_gem_open - initalizes GEM file-private structures at devnode open time
* @dev: drm_device which is being opened by userspace
* @file_private: drm file-private structure to set up
*
* 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_file *file_priv = data;
struct drm_gem_object *obj = ptr;
struct drm_device *dev = obj->dev;
if (drm_core_check_feature(dev, DRIVER_PRIME))
drm_gem_remove_prime_handles(obj, file_priv);
drm_vma_node_revoke(&obj->vma_node, file_priv->filp);
if (dev->driver->gem_close_object)
dev->driver->gem_close_object(obj, file_priv);
drm_gem_object_handle_unreference_unlocked(obj);
return 0;
}
/**
* drm_gem_release - release file-private GEM resources
* @dev: drm_device which is being closed by userspace
* @file_private: drm file-private structure to clean up
*
* 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, file_private);
idr_destroy(&file_private->object_idr);
}
void
drm_gem_object_release(struct drm_gem_object *obj)
{
WARN_ON(obj->dma_buf);
if (obj->filp)
fput(obj->filp);
drm_gem_free_mmap_offset(obj);
}
EXPORT_SYMBOL(drm_gem_object_release);
/**
* drm_gem_object_free - free a GEM object
* @kref: kref of the object to free
*
* 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);
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(obj->dev, 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(obj->dev, vma);
drm_gem_object_unreference(obj);
mutex_unlock(&dev->struct_mutex);
}
EXPORT_SYMBOL(drm_gem_vm_close);
/**
* drm_gem_mmap_obj - memory map a GEM object
* @obj: the GEM object to map
* @obj_size: the object size to be mapped, in bytes
* @vma: VMA for the area to be mapped
*
* Set up the VMA to prepare mapping of the GEM object using the gem_vm_ops
* provided by the driver. Depending on their requirements, drivers can either
* provide a fault handler in their gem_vm_ops (in which case any accesses to
* the object will be trapped, to perform migration, GTT binding, surface
* register allocation, or performance monitoring), or mmap the buffer memory
* synchronously after calling drm_gem_mmap_obj.
*
* This function is mainly intended to implement the DMABUF mmap operation, when
* the GEM object is not looked up based on its fake offset. To implement the
* DRM mmap operation, drivers should use the drm_gem_mmap() function.
*
* drm_gem_mmap_obj() assumes the user is granted access to the buffer while
* drm_gem_mmap() prevents unprivileged users from mapping random objects. So
* callers must verify access restrictions before calling this helper.
*
* NOTE: This function has to be protected with dev->struct_mutex
*
* Return 0 or success or -EINVAL if the object size is smaller than the VMA
* size, or if no gem_vm_ops are provided.
*/
int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size,
struct vm_area_struct *vma)
{
struct drm_device *dev = obj->dev;
lockdep_assert_held(&dev->struct_mutex);
/* Check for valid size. */
if (obj_size < vma->vm_end - vma->vm_start)
return -EINVAL;
if (!dev->driver->gem_vm_ops)
return -EINVAL;
vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
vma->vm_ops = dev->driver->gem_vm_ops;
vma->vm_private_data = obj;
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);
drm_vm_open_locked(dev, vma);
return 0;
}
EXPORT_SYMBOL(drm_gem_mmap_obj);
/**
* 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.
*
* Look up the GEM 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) and map it with a call to drm_gem_mmap_obj().
*
* If the caller is not granted access to the buffer object, the mmap will fail
* with EACCES. Please see the vma manager for more information.
*/
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_object *obj;
struct drm_vma_offset_node *node;
int ret;
if (drm_device_is_unplugged(dev))
return -ENODEV;
mutex_lock(&dev->struct_mutex);
node = drm_vma_offset_exact_lookup(dev->vma_offset_manager,
vma->vm_pgoff,
vma_pages(vma));
if (!node) {
mutex_unlock(&dev->struct_mutex);
return -EINVAL;
} else if (!drm_vma_node_is_allowed(node, filp)) {
mutex_unlock(&dev->struct_mutex);
return -EACCES;
}
obj = container_of(node, struct drm_gem_object, vma_node);
ret = drm_gem_mmap_obj(obj, drm_vma_node_size(node) << PAGE_SHIFT, vma);
mutex_unlock(&dev->struct_mutex);
return ret;
}
EXPORT_SYMBOL(drm_gem_mmap);