/* * 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 * */ #include #include #include #include #include #include #include #include #include #include #include #include #include /** @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; mutex_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; drm_vma_offset_manager_init(&mm->vma_manager, DRM_FILE_PAGE_OFFSET_START, DRM_FILE_PAGE_OFFSET_SIZE); return 0; } void drm_gem_destroy(struct drm_device *dev) { struct drm_gem_mm *mm = dev->mm_private; drm_vma_offset_manager_destroy(&mm->vma_manager); kfree(mm); dev->mm_private = NULL; } /** * 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; filp = shmem_file_setup("drm mm object", size, VM_NORESERVE); if (IS_ERR(filp)) return PTR_ERR(filp); drm_gem_private_object_init(dev, obj, size); obj->filp = filp; return 0; } EXPORT_SYMBOL(drm_gem_object_init); /** * 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); } 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 */ 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; /* * 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); } } 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); } /** * 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); 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 * * 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 * * 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; } /** * 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; struct drm_gem_mm *mm = dev->mm_private; drm_vma_offset_remove(&mm->vma_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; struct drm_gem_mm *mm = dev->mm_private; return drm_vma_offset_add(&mm->vma_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 * @gfpmask: gfp mask of requested pages */ struct page **drm_gem_get_pages(struct drm_gem_object *obj, gfp_t gfpmask) { struct inode *inode; struct address_space *mapping; struct page *p, **pages; int i, npages; /* This is the shared memory object that backs the GEM resource */ inode = file_inode(obj->filp); mapping = inode->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); gfpmask |= mapping_gfp_mask(mapping); for (i = 0; i < npages; i++) { p = shmem_read_mapping_page_gfp(mapping, i, gfpmask); if (IS_ERR(p)) goto fail; pages[i] = p; /* There is a hypothetical issue w/ drivers that require * buffer memory in the low 4GB.. if the pages are un- * pinned, and swapped out, they can end up swapped back * in above 4GB. If pages are already in memory, then * shmem_read_mapping_page_gfp will ignore the gfpmask, * even if the already in-memory page disobeys the mask. * * It is only a theoretical issue today, because none of * the devices with this limitation can be populated with * enough memory to trigger the issue. But this BUG_ON() * is here as a reminder in case the problem with * shmem_read_mapping_page_gfp() isn't solved by the time * it does become a real issue. * * See this thread: http://lkml.org/lkml/2011/7/11/238 */ BUG_ON((gfpmask & __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); /** * 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; 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; /* Allocate a reference for the name table. */ drm_gem_object_reference(obj); } 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; } /** * 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; 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; } /** * 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; } /** * 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); } 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); 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_mm *mm = dev->mm_private; struct drm_gem_object *obj; struct drm_vma_offset_node *node; int ret = 0; if (drm_device_is_unplugged(dev)) return -ENODEV; mutex_lock(&dev->struct_mutex); node = drm_vma_offset_exact_lookup(&mm->vma_manager, vma->vm_pgoff, vma_pages(vma)); if (!node) { mutex_unlock(&dev->struct_mutex); return drm_mmap(filp, vma); } 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);