| /* |
| * SPDX-License-Identifier: MIT |
| * |
| * Copyright © 2012-2014 Intel Corporation |
| */ |
| |
| #include <linux/mmu_context.h> |
| #include <linux/mmu_notifier.h> |
| #include <linux/mempolicy.h> |
| #include <linux/swap.h> |
| #include <linux/sched/mm.h> |
| |
| #include "i915_drv.h" |
| #include "i915_gem_ioctls.h" |
| #include "i915_gem_object.h" |
| #include "i915_scatterlist.h" |
| |
| struct i915_mm_struct { |
| struct mm_struct *mm; |
| struct drm_i915_private *i915; |
| struct i915_mmu_notifier *mn; |
| struct hlist_node node; |
| struct kref kref; |
| struct work_struct work; |
| }; |
| |
| #if defined(CONFIG_MMU_NOTIFIER) |
| #include <linux/interval_tree.h> |
| |
| struct i915_mmu_notifier { |
| spinlock_t lock; |
| struct hlist_node node; |
| struct mmu_notifier mn; |
| struct rb_root_cached objects; |
| struct i915_mm_struct *mm; |
| }; |
| |
| struct i915_mmu_object { |
| struct i915_mmu_notifier *mn; |
| struct drm_i915_gem_object *obj; |
| struct interval_tree_node it; |
| }; |
| |
| static void add_object(struct i915_mmu_object *mo) |
| { |
| GEM_BUG_ON(!RB_EMPTY_NODE(&mo->it.rb)); |
| interval_tree_insert(&mo->it, &mo->mn->objects); |
| } |
| |
| static void del_object(struct i915_mmu_object *mo) |
| { |
| if (RB_EMPTY_NODE(&mo->it.rb)) |
| return; |
| |
| interval_tree_remove(&mo->it, &mo->mn->objects); |
| RB_CLEAR_NODE(&mo->it.rb); |
| } |
| |
| static void |
| __i915_gem_userptr_set_active(struct drm_i915_gem_object *obj, bool value) |
| { |
| struct i915_mmu_object *mo = obj->userptr.mmu_object; |
| |
| /* |
| * During mm_invalidate_range we need to cancel any userptr that |
| * overlaps the range being invalidated. Doing so requires the |
| * struct_mutex, and that risks recursion. In order to cause |
| * recursion, the user must alias the userptr address space with |
| * a GTT mmapping (possible with a MAP_FIXED) - then when we have |
| * to invalidate that mmaping, mm_invalidate_range is called with |
| * the userptr address *and* the struct_mutex held. To prevent that |
| * we set a flag under the i915_mmu_notifier spinlock to indicate |
| * whether this object is valid. |
| */ |
| if (!mo) |
| return; |
| |
| spin_lock(&mo->mn->lock); |
| if (value) |
| add_object(mo); |
| else |
| del_object(mo); |
| spin_unlock(&mo->mn->lock); |
| } |
| |
| static int |
| userptr_mn_invalidate_range_start(struct mmu_notifier *_mn, |
| const struct mmu_notifier_range *range) |
| { |
| struct i915_mmu_notifier *mn = |
| container_of(_mn, struct i915_mmu_notifier, mn); |
| struct interval_tree_node *it; |
| unsigned long end; |
| int ret = 0; |
| |
| if (RB_EMPTY_ROOT(&mn->objects.rb_root)) |
| return 0; |
| |
| /* interval ranges are inclusive, but invalidate range is exclusive */ |
| end = range->end - 1; |
| |
| spin_lock(&mn->lock); |
| it = interval_tree_iter_first(&mn->objects, range->start, end); |
| while (it) { |
| struct drm_i915_gem_object *obj; |
| |
| if (!mmu_notifier_range_blockable(range)) { |
| ret = -EAGAIN; |
| break; |
| } |
| |
| /* |
| * The mmu_object is released late when destroying the |
| * GEM object so it is entirely possible to gain a |
| * reference on an object in the process of being freed |
| * since our serialisation is via the spinlock and not |
| * the struct_mutex - and consequently use it after it |
| * is freed and then double free it. To prevent that |
| * use-after-free we only acquire a reference on the |
| * object if it is not in the process of being destroyed. |
| */ |
| obj = container_of(it, struct i915_mmu_object, it)->obj; |
| if (!kref_get_unless_zero(&obj->base.refcount)) { |
| it = interval_tree_iter_next(it, range->start, end); |
| continue; |
| } |
| spin_unlock(&mn->lock); |
| |
| ret = i915_gem_object_unbind(obj, |
| I915_GEM_OBJECT_UNBIND_ACTIVE | |
| I915_GEM_OBJECT_UNBIND_BARRIER); |
| if (ret == 0) |
| ret = __i915_gem_object_put_pages(obj); |
| i915_gem_object_put(obj); |
| if (ret) |
| return ret; |
| |
| spin_lock(&mn->lock); |
| |
| /* |
| * As we do not (yet) protect the mmu from concurrent insertion |
| * over this range, there is no guarantee that this search will |
| * terminate given a pathologic workload. |
| */ |
| it = interval_tree_iter_first(&mn->objects, range->start, end); |
| } |
| spin_unlock(&mn->lock); |
| |
| return ret; |
| |
| } |
| |
| static const struct mmu_notifier_ops i915_gem_userptr_notifier = { |
| .invalidate_range_start = userptr_mn_invalidate_range_start, |
| }; |
| |
| static struct i915_mmu_notifier * |
| i915_mmu_notifier_create(struct i915_mm_struct *mm) |
| { |
| struct i915_mmu_notifier *mn; |
| |
| mn = kmalloc(sizeof(*mn), GFP_KERNEL); |
| if (mn == NULL) |
| return ERR_PTR(-ENOMEM); |
| |
| spin_lock_init(&mn->lock); |
| mn->mn.ops = &i915_gem_userptr_notifier; |
| mn->objects = RB_ROOT_CACHED; |
| mn->mm = mm; |
| |
| return mn; |
| } |
| |
| static void |
| i915_gem_userptr_release__mmu_notifier(struct drm_i915_gem_object *obj) |
| { |
| struct i915_mmu_object *mo; |
| |
| mo = fetch_and_zero(&obj->userptr.mmu_object); |
| if (!mo) |
| return; |
| |
| spin_lock(&mo->mn->lock); |
| del_object(mo); |
| spin_unlock(&mo->mn->lock); |
| kfree(mo); |
| } |
| |
| static struct i915_mmu_notifier * |
| i915_mmu_notifier_find(struct i915_mm_struct *mm) |
| { |
| struct i915_mmu_notifier *mn; |
| int err = 0; |
| |
| mn = mm->mn; |
| if (mn) |
| return mn; |
| |
| mn = i915_mmu_notifier_create(mm); |
| if (IS_ERR(mn)) |
| err = PTR_ERR(mn); |
| |
| mmap_write_lock(mm->mm); |
| mutex_lock(&mm->i915->mm_lock); |
| if (mm->mn == NULL && !err) { |
| /* Protected by mmap_lock (write-lock) */ |
| err = __mmu_notifier_register(&mn->mn, mm->mm); |
| if (!err) { |
| /* Protected by mm_lock */ |
| mm->mn = fetch_and_zero(&mn); |
| } |
| } else if (mm->mn) { |
| /* |
| * Someone else raced and successfully installed the mmu |
| * notifier, we can cancel our own errors. |
| */ |
| err = 0; |
| } |
| mutex_unlock(&mm->i915->mm_lock); |
| mmap_write_unlock(mm->mm); |
| |
| if (mn && !IS_ERR(mn)) |
| kfree(mn); |
| |
| return err ? ERR_PTR(err) : mm->mn; |
| } |
| |
| static int |
| i915_gem_userptr_init__mmu_notifier(struct drm_i915_gem_object *obj, |
| unsigned flags) |
| { |
| struct i915_mmu_notifier *mn; |
| struct i915_mmu_object *mo; |
| |
| if (flags & I915_USERPTR_UNSYNCHRONIZED) |
| return capable(CAP_SYS_ADMIN) ? 0 : -EPERM; |
| |
| if (WARN_ON(obj->userptr.mm == NULL)) |
| return -EINVAL; |
| |
| mn = i915_mmu_notifier_find(obj->userptr.mm); |
| if (IS_ERR(mn)) |
| return PTR_ERR(mn); |
| |
| mo = kzalloc(sizeof(*mo), GFP_KERNEL); |
| if (!mo) |
| return -ENOMEM; |
| |
| mo->mn = mn; |
| mo->obj = obj; |
| mo->it.start = obj->userptr.ptr; |
| mo->it.last = obj->userptr.ptr + obj->base.size - 1; |
| RB_CLEAR_NODE(&mo->it.rb); |
| |
| obj->userptr.mmu_object = mo; |
| return 0; |
| } |
| |
| static void |
| i915_mmu_notifier_free(struct i915_mmu_notifier *mn, |
| struct mm_struct *mm) |
| { |
| if (mn == NULL) |
| return; |
| |
| mmu_notifier_unregister(&mn->mn, mm); |
| kfree(mn); |
| } |
| |
| #else |
| |
| static void |
| __i915_gem_userptr_set_active(struct drm_i915_gem_object *obj, bool value) |
| { |
| } |
| |
| static void |
| i915_gem_userptr_release__mmu_notifier(struct drm_i915_gem_object *obj) |
| { |
| } |
| |
| static int |
| i915_gem_userptr_init__mmu_notifier(struct drm_i915_gem_object *obj, |
| unsigned flags) |
| { |
| if ((flags & I915_USERPTR_UNSYNCHRONIZED) == 0) |
| return -ENODEV; |
| |
| if (!capable(CAP_SYS_ADMIN)) |
| return -EPERM; |
| |
| return 0; |
| } |
| |
| static void |
| i915_mmu_notifier_free(struct i915_mmu_notifier *mn, |
| struct mm_struct *mm) |
| { |
| } |
| |
| #endif |
| |
| static struct i915_mm_struct * |
| __i915_mm_struct_find(struct drm_i915_private *dev_priv, struct mm_struct *real) |
| { |
| struct i915_mm_struct *mm; |
| |
| /* Protected by dev_priv->mm_lock */ |
| hash_for_each_possible(dev_priv->mm_structs, mm, node, (unsigned long)real) |
| if (mm->mm == real) |
| return mm; |
| |
| return NULL; |
| } |
| |
| static int |
| i915_gem_userptr_init__mm_struct(struct drm_i915_gem_object *obj) |
| { |
| struct drm_i915_private *dev_priv = to_i915(obj->base.dev); |
| struct i915_mm_struct *mm; |
| int ret = 0; |
| |
| /* During release of the GEM object we hold the struct_mutex. This |
| * precludes us from calling mmput() at that time as that may be |
| * the last reference and so call exit_mmap(). exit_mmap() will |
| * attempt to reap the vma, and if we were holding a GTT mmap |
| * would then call drm_gem_vm_close() and attempt to reacquire |
| * the struct mutex. So in order to avoid that recursion, we have |
| * to defer releasing the mm reference until after we drop the |
| * struct_mutex, i.e. we need to schedule a worker to do the clean |
| * up. |
| */ |
| mutex_lock(&dev_priv->mm_lock); |
| mm = __i915_mm_struct_find(dev_priv, current->mm); |
| if (mm == NULL) { |
| mm = kmalloc(sizeof(*mm), GFP_KERNEL); |
| if (mm == NULL) { |
| ret = -ENOMEM; |
| goto out; |
| } |
| |
| kref_init(&mm->kref); |
| mm->i915 = to_i915(obj->base.dev); |
| |
| mm->mm = current->mm; |
| mmgrab(current->mm); |
| |
| mm->mn = NULL; |
| |
| /* Protected by dev_priv->mm_lock */ |
| hash_add(dev_priv->mm_structs, |
| &mm->node, (unsigned long)mm->mm); |
| } else |
| kref_get(&mm->kref); |
| |
| obj->userptr.mm = mm; |
| out: |
| mutex_unlock(&dev_priv->mm_lock); |
| return ret; |
| } |
| |
| static void |
| __i915_mm_struct_free__worker(struct work_struct *work) |
| { |
| struct i915_mm_struct *mm = container_of(work, typeof(*mm), work); |
| i915_mmu_notifier_free(mm->mn, mm->mm); |
| mmdrop(mm->mm); |
| kfree(mm); |
| } |
| |
| static void |
| __i915_mm_struct_free(struct kref *kref) |
| { |
| struct i915_mm_struct *mm = container_of(kref, typeof(*mm), kref); |
| |
| /* Protected by dev_priv->mm_lock */ |
| hash_del(&mm->node); |
| mutex_unlock(&mm->i915->mm_lock); |
| |
| INIT_WORK(&mm->work, __i915_mm_struct_free__worker); |
| queue_work(mm->i915->mm.userptr_wq, &mm->work); |
| } |
| |
| static void |
| i915_gem_userptr_release__mm_struct(struct drm_i915_gem_object *obj) |
| { |
| if (obj->userptr.mm == NULL) |
| return; |
| |
| kref_put_mutex(&obj->userptr.mm->kref, |
| __i915_mm_struct_free, |
| &to_i915(obj->base.dev)->mm_lock); |
| obj->userptr.mm = NULL; |
| } |
| |
| struct get_pages_work { |
| struct work_struct work; |
| struct drm_i915_gem_object *obj; |
| struct task_struct *task; |
| }; |
| |
| static struct sg_table * |
| __i915_gem_userptr_alloc_pages(struct drm_i915_gem_object *obj, |
| struct page **pvec, unsigned long num_pages) |
| { |
| unsigned int max_segment = i915_sg_segment_size(); |
| struct sg_table *st; |
| unsigned int sg_page_sizes; |
| int ret; |
| |
| st = kmalloc(sizeof(*st), GFP_KERNEL); |
| if (!st) |
| return ERR_PTR(-ENOMEM); |
| |
| alloc_table: |
| ret = __sg_alloc_table_from_pages(st, pvec, num_pages, |
| 0, num_pages << PAGE_SHIFT, |
| max_segment, |
| GFP_KERNEL); |
| if (ret) { |
| kfree(st); |
| return ERR_PTR(ret); |
| } |
| |
| ret = i915_gem_gtt_prepare_pages(obj, st); |
| if (ret) { |
| sg_free_table(st); |
| |
| if (max_segment > PAGE_SIZE) { |
| max_segment = PAGE_SIZE; |
| goto alloc_table; |
| } |
| |
| kfree(st); |
| return ERR_PTR(ret); |
| } |
| |
| sg_page_sizes = i915_sg_page_sizes(st->sgl); |
| |
| __i915_gem_object_set_pages(obj, st, sg_page_sizes); |
| |
| return st; |
| } |
| |
| static void |
| __i915_gem_userptr_get_pages_worker(struct work_struct *_work) |
| { |
| struct get_pages_work *work = container_of(_work, typeof(*work), work); |
| struct drm_i915_gem_object *obj = work->obj; |
| const unsigned long npages = obj->base.size >> PAGE_SHIFT; |
| unsigned long pinned; |
| struct page **pvec; |
| int ret; |
| |
| ret = -ENOMEM; |
| pinned = 0; |
| |
| pvec = kvmalloc_array(npages, sizeof(struct page *), GFP_KERNEL); |
| if (pvec != NULL) { |
| struct mm_struct *mm = obj->userptr.mm->mm; |
| unsigned int flags = 0; |
| int locked = 0; |
| |
| if (!i915_gem_object_is_readonly(obj)) |
| flags |= FOLL_WRITE; |
| |
| ret = -EFAULT; |
| if (mmget_not_zero(mm)) { |
| while (pinned < npages) { |
| if (!locked) { |
| mmap_read_lock(mm); |
| locked = 1; |
| } |
| ret = pin_user_pages_remote |
| (work->task, mm, |
| obj->userptr.ptr + pinned * PAGE_SIZE, |
| npages - pinned, |
| flags, |
| pvec + pinned, NULL, &locked); |
| if (ret < 0) |
| break; |
| |
| pinned += ret; |
| } |
| if (locked) |
| mmap_read_unlock(mm); |
| mmput(mm); |
| } |
| } |
| |
| mutex_lock_nested(&obj->mm.lock, I915_MM_GET_PAGES); |
| if (obj->userptr.work == &work->work) { |
| struct sg_table *pages = ERR_PTR(ret); |
| |
| if (pinned == npages) { |
| pages = __i915_gem_userptr_alloc_pages(obj, pvec, |
| npages); |
| if (!IS_ERR(pages)) { |
| pinned = 0; |
| pages = NULL; |
| } |
| } |
| |
| obj->userptr.work = ERR_CAST(pages); |
| if (IS_ERR(pages)) |
| __i915_gem_userptr_set_active(obj, false); |
| } |
| mutex_unlock(&obj->mm.lock); |
| |
| unpin_user_pages(pvec, pinned); |
| kvfree(pvec); |
| |
| i915_gem_object_put(obj); |
| put_task_struct(work->task); |
| kfree(work); |
| } |
| |
| static struct sg_table * |
| __i915_gem_userptr_get_pages_schedule(struct drm_i915_gem_object *obj) |
| { |
| struct get_pages_work *work; |
| |
| /* Spawn a worker so that we can acquire the |
| * user pages without holding our mutex. Access |
| * to the user pages requires mmap_lock, and we have |
| * a strict lock ordering of mmap_lock, struct_mutex - |
| * we already hold struct_mutex here and so cannot |
| * call gup without encountering a lock inversion. |
| * |
| * Userspace will keep on repeating the operation |
| * (thanks to EAGAIN) until either we hit the fast |
| * path or the worker completes. If the worker is |
| * cancelled or superseded, the task is still run |
| * but the results ignored. (This leads to |
| * complications that we may have a stray object |
| * refcount that we need to be wary of when |
| * checking for existing objects during creation.) |
| * If the worker encounters an error, it reports |
| * that error back to this function through |
| * obj->userptr.work = ERR_PTR. |
| */ |
| work = kmalloc(sizeof(*work), GFP_KERNEL); |
| if (work == NULL) |
| return ERR_PTR(-ENOMEM); |
| |
| obj->userptr.work = &work->work; |
| |
| work->obj = i915_gem_object_get(obj); |
| |
| work->task = current; |
| get_task_struct(work->task); |
| |
| INIT_WORK(&work->work, __i915_gem_userptr_get_pages_worker); |
| queue_work(to_i915(obj->base.dev)->mm.userptr_wq, &work->work); |
| |
| return ERR_PTR(-EAGAIN); |
| } |
| |
| static int i915_gem_userptr_get_pages(struct drm_i915_gem_object *obj) |
| { |
| const unsigned long num_pages = obj->base.size >> PAGE_SHIFT; |
| struct mm_struct *mm = obj->userptr.mm->mm; |
| struct page **pvec; |
| struct sg_table *pages; |
| bool active; |
| int pinned; |
| unsigned int gup_flags = 0; |
| |
| /* If userspace should engineer that these pages are replaced in |
| * the vma between us binding this page into the GTT and completion |
| * of rendering... Their loss. If they change the mapping of their |
| * pages they need to create a new bo to point to the new vma. |
| * |
| * However, that still leaves open the possibility of the vma |
| * being copied upon fork. Which falls under the same userspace |
| * synchronisation issue as a regular bo, except that this time |
| * the process may not be expecting that a particular piece of |
| * memory is tied to the GPU. |
| * |
| * Fortunately, we can hook into the mmu_notifier in order to |
| * discard the page references prior to anything nasty happening |
| * to the vma (discard or cloning) which should prevent the more |
| * egregious cases from causing harm. |
| */ |
| |
| if (obj->userptr.work) { |
| /* active flag should still be held for the pending work */ |
| if (IS_ERR(obj->userptr.work)) |
| return PTR_ERR(obj->userptr.work); |
| else |
| return -EAGAIN; |
| } |
| |
| pvec = NULL; |
| pinned = 0; |
| |
| if (mm == current->mm) { |
| pvec = kvmalloc_array(num_pages, sizeof(struct page *), |
| GFP_KERNEL | |
| __GFP_NORETRY | |
| __GFP_NOWARN); |
| if (pvec) { |
| /* defer to worker if malloc fails */ |
| if (!i915_gem_object_is_readonly(obj)) |
| gup_flags |= FOLL_WRITE; |
| pinned = pin_user_pages_fast_only(obj->userptr.ptr, |
| num_pages, gup_flags, |
| pvec); |
| } |
| } |
| |
| active = false; |
| if (pinned < 0) { |
| pages = ERR_PTR(pinned); |
| pinned = 0; |
| } else if (pinned < num_pages) { |
| pages = __i915_gem_userptr_get_pages_schedule(obj); |
| active = pages == ERR_PTR(-EAGAIN); |
| } else { |
| pages = __i915_gem_userptr_alloc_pages(obj, pvec, num_pages); |
| active = !IS_ERR(pages); |
| } |
| if (active) |
| __i915_gem_userptr_set_active(obj, true); |
| |
| if (IS_ERR(pages)) |
| unpin_user_pages(pvec, pinned); |
| kvfree(pvec); |
| |
| return PTR_ERR_OR_ZERO(pages); |
| } |
| |
| static void |
| i915_gem_userptr_put_pages(struct drm_i915_gem_object *obj, |
| struct sg_table *pages) |
| { |
| struct sgt_iter sgt_iter; |
| struct page *page; |
| |
| /* Cancel any inflight work and force them to restart their gup */ |
| obj->userptr.work = NULL; |
| __i915_gem_userptr_set_active(obj, false); |
| if (!pages) |
| return; |
| |
| __i915_gem_object_release_shmem(obj, pages, true); |
| i915_gem_gtt_finish_pages(obj, pages); |
| |
| /* |
| * We always mark objects as dirty when they are used by the GPU, |
| * just in case. However, if we set the vma as being read-only we know |
| * that the object will never have been written to. |
| */ |
| if (i915_gem_object_is_readonly(obj)) |
| obj->mm.dirty = false; |
| |
| for_each_sgt_page(page, sgt_iter, pages) { |
| if (obj->mm.dirty && trylock_page(page)) { |
| /* |
| * As this may not be anonymous memory (e.g. shmem) |
| * but exist on a real mapping, we have to lock |
| * the page in order to dirty it -- holding |
| * the page reference is not sufficient to |
| * prevent the inode from being truncated. |
| * Play safe and take the lock. |
| * |
| * However...! |
| * |
| * The mmu-notifier can be invalidated for a |
| * migrate_page, that is alreadying holding the lock |
| * on the page. Such a try_to_unmap() will result |
| * in us calling put_pages() and so recursively try |
| * to lock the page. We avoid that deadlock with |
| * a trylock_page() and in exchange we risk missing |
| * some page dirtying. |
| */ |
| set_page_dirty(page); |
| unlock_page(page); |
| } |
| |
| mark_page_accessed(page); |
| unpin_user_page(page); |
| } |
| obj->mm.dirty = false; |
| |
| sg_free_table(pages); |
| kfree(pages); |
| } |
| |
| static void |
| i915_gem_userptr_release(struct drm_i915_gem_object *obj) |
| { |
| i915_gem_userptr_release__mmu_notifier(obj); |
| i915_gem_userptr_release__mm_struct(obj); |
| } |
| |
| static int |
| i915_gem_userptr_dmabuf_export(struct drm_i915_gem_object *obj) |
| { |
| if (obj->userptr.mmu_object) |
| return 0; |
| |
| return i915_gem_userptr_init__mmu_notifier(obj, 0); |
| } |
| |
| static const struct drm_i915_gem_object_ops i915_gem_userptr_ops = { |
| .flags = I915_GEM_OBJECT_HAS_STRUCT_PAGE | |
| I915_GEM_OBJECT_IS_SHRINKABLE | |
| I915_GEM_OBJECT_NO_MMAP | |
| I915_GEM_OBJECT_ASYNC_CANCEL, |
| .get_pages = i915_gem_userptr_get_pages, |
| .put_pages = i915_gem_userptr_put_pages, |
| .dmabuf_export = i915_gem_userptr_dmabuf_export, |
| .release = i915_gem_userptr_release, |
| }; |
| |
| /* |
| * Creates a new mm object that wraps some normal memory from the process |
| * context - user memory. |
| * |
| * We impose several restrictions upon the memory being mapped |
| * into the GPU. |
| * 1. It must be page aligned (both start/end addresses, i.e ptr and size). |
| * 2. It must be normal system memory, not a pointer into another map of IO |
| * space (e.g. it must not be a GTT mmapping of another object). |
| * 3. We only allow a bo as large as we could in theory map into the GTT, |
| * that is we limit the size to the total size of the GTT. |
| * 4. The bo is marked as being snoopable. The backing pages are left |
| * accessible directly by the CPU, but reads and writes by the GPU may |
| * incur the cost of a snoop (unless you have an LLC architecture). |
| * |
| * Synchronisation between multiple users and the GPU is left to userspace |
| * through the normal set-domain-ioctl. The kernel will enforce that the |
| * GPU relinquishes the VMA before it is returned back to the system |
| * i.e. upon free(), munmap() or process termination. However, the userspace |
| * malloc() library may not immediately relinquish the VMA after free() and |
| * instead reuse it whilst the GPU is still reading and writing to the VMA. |
| * Caveat emptor. |
| * |
| * Also note, that the object created here is not currently a "first class" |
| * object, in that several ioctls are banned. These are the CPU access |
| * ioctls: mmap(), pwrite and pread. In practice, you are expected to use |
| * direct access via your pointer rather than use those ioctls. Another |
| * restriction is that we do not allow userptr surfaces to be pinned to the |
| * hardware and so we reject any attempt to create a framebuffer out of a |
| * userptr. |
| * |
| * If you think this is a good interface to use to pass GPU memory between |
| * drivers, please use dma-buf instead. In fact, wherever possible use |
| * dma-buf instead. |
| */ |
| int |
| i915_gem_userptr_ioctl(struct drm_device *dev, |
| void *data, |
| struct drm_file *file) |
| { |
| static struct lock_class_key lock_class; |
| struct drm_i915_private *dev_priv = to_i915(dev); |
| struct drm_i915_gem_userptr *args = data; |
| struct drm_i915_gem_object *obj; |
| int ret; |
| u32 handle; |
| |
| if (!HAS_LLC(dev_priv) && !HAS_SNOOP(dev_priv)) { |
| /* We cannot support coherent userptr objects on hw without |
| * LLC and broken snooping. |
| */ |
| return -ENODEV; |
| } |
| |
| if (args->flags & ~(I915_USERPTR_READ_ONLY | |
| I915_USERPTR_UNSYNCHRONIZED)) |
| return -EINVAL; |
| |
| /* |
| * XXX: There is a prevalence of the assumption that we fit the |
| * object's page count inside a 32bit _signed_ variable. Let's document |
| * this and catch if we ever need to fix it. In the meantime, if you do |
| * spot such a local variable, please consider fixing! |
| * |
| * Aside from our own locals (for which we have no excuse!): |
| * - sg_table embeds unsigned int for num_pages |
| * - get_user_pages*() mixed ints with longs |
| */ |
| |
| if (args->user_size >> PAGE_SHIFT > INT_MAX) |
| return -E2BIG; |
| |
| if (overflows_type(args->user_size, obj->base.size)) |
| return -E2BIG; |
| |
| if (!args->user_size) |
| return -EINVAL; |
| |
| if (offset_in_page(args->user_ptr | args->user_size)) |
| return -EINVAL; |
| |
| if (!access_ok((char __user *)(unsigned long)args->user_ptr, args->user_size)) |
| return -EFAULT; |
| |
| if (args->flags & I915_USERPTR_READ_ONLY) { |
| /* |
| * On almost all of the older hw, we cannot tell the GPU that |
| * a page is readonly. |
| */ |
| if (!dev_priv->gt.vm->has_read_only) |
| return -ENODEV; |
| } |
| |
| obj = i915_gem_object_alloc(); |
| if (obj == NULL) |
| return -ENOMEM; |
| |
| drm_gem_private_object_init(dev, &obj->base, args->user_size); |
| i915_gem_object_init(obj, &i915_gem_userptr_ops, &lock_class); |
| obj->read_domains = I915_GEM_DOMAIN_CPU; |
| obj->write_domain = I915_GEM_DOMAIN_CPU; |
| i915_gem_object_set_cache_coherency(obj, I915_CACHE_LLC); |
| |
| obj->userptr.ptr = args->user_ptr; |
| if (args->flags & I915_USERPTR_READ_ONLY) |
| i915_gem_object_set_readonly(obj); |
| |
| /* And keep a pointer to the current->mm for resolving the user pages |
| * at binding. This means that we need to hook into the mmu_notifier |
| * in order to detect if the mmu is destroyed. |
| */ |
| ret = i915_gem_userptr_init__mm_struct(obj); |
| if (ret == 0) |
| ret = i915_gem_userptr_init__mmu_notifier(obj, args->flags); |
| if (ret == 0) |
| ret = drm_gem_handle_create(file, &obj->base, &handle); |
| |
| /* drop reference from allocate - handle holds it now */ |
| i915_gem_object_put(obj); |
| if (ret) |
| return ret; |
| |
| args->handle = handle; |
| return 0; |
| } |
| |
| int i915_gem_init_userptr(struct drm_i915_private *dev_priv) |
| { |
| mutex_init(&dev_priv->mm_lock); |
| hash_init(dev_priv->mm_structs); |
| |
| dev_priv->mm.userptr_wq = |
| alloc_workqueue("i915-userptr-acquire", |
| WQ_HIGHPRI | WQ_UNBOUND, |
| 0); |
| if (!dev_priv->mm.userptr_wq) |
| return -ENOMEM; |
| |
| return 0; |
| } |
| |
| void i915_gem_cleanup_userptr(struct drm_i915_private *dev_priv) |
| { |
| destroy_workqueue(dev_priv->mm.userptr_wq); |
| } |