/* * 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 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) { 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 PTR_ERR(obj->filp); kref_init(&obj->refcount); atomic_set(&obj->handle_count, 0); obj->size = size; 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. */ int 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); atomic_set(&obj->handle_count, 0); obj->size = size; return 0; } EXPORT_SYMBOL(drm_gem_private_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); 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); /** * 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) { struct drm_device *dev = obj->dev; 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); 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; } 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; struct drm_map_list *list = &obj->map_list; drm_ht_remove_item(&mm->offset_hash, &list->hash); drm_mm_put_block(list->file_offset_node); kfree(list->map); list->map = NULL; } EXPORT_SYMBOL(drm_gem_free_mmap_offset); /** * 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) { struct drm_device *dev = obj->dev; struct drm_gem_mm *mm = dev->mm_private; struct drm_map_list *list; struct drm_local_map *map; int ret = 0; /* Set the object up for mmap'ing */ list = &obj->map_list; list->map = kzalloc(sizeof(struct drm_map_list), GFP_KERNEL); if (!list->map) return -ENOMEM; map = list->map; map->type = _DRM_GEM; map->size = obj->size; map->handle = obj; /* Get a DRM GEM mmap offset allocated... */ list->file_offset_node = drm_mm_search_free(&mm->offset_manager, obj->size / PAGE_SIZE, 0, 0); if (!list->file_offset_node) { DRM_ERROR("failed to allocate offset for bo %d\n", obj->name); ret = -ENOSPC; goto out_free_list; } list->file_offset_node = drm_mm_get_block(list->file_offset_node, obj->size / PAGE_SIZE, 0); if (!list->file_offset_node) { ret = -ENOMEM; goto out_free_list; } list->hash.key = list->file_offset_node->start; ret = drm_ht_insert_item(&mm->offset_hash, &list->hash); if (ret) { DRM_ERROR("failed to add to map hash\n"); goto out_free_mm; } return 0; out_free_mm: drm_mm_put_block(list->file_offset_node); out_free_list: kfree(list->map); list->map = NULL; return ret; } EXPORT_SYMBOL(drm_gem_create_mmap_offset); /** 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_file *file_priv = data; struct drm_gem_object *obj = ptr; struct drm_device *dev = obj->dev; 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_remove_all(&file_private->object_idr); idr_destroy(&file_private->object_idr); } void drm_gem_object_release(struct drm_gem_object *obj) { 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); 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);