| /* |
| * Copyright © 2012-2014 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. |
| * |
| */ |
| |
| #include <drm/drmP.h> |
| #include <drm/i915_drm.h> |
| #include "i915_drv.h" |
| #include "i915_trace.h" |
| #include "intel_drv.h" |
| #include <linux/mmu_context.h> |
| #include <linux/mmu_notifier.h> |
| #include <linux/mempolicy.h> |
| #include <linux/swap.h> |
| #include <linux/sched/mm.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 workqueue_struct *wq; |
| }; |
| |
| struct i915_mmu_object { |
| struct i915_mmu_notifier *mn; |
| struct drm_i915_gem_object *obj; |
| struct interval_tree_node it; |
| struct list_head link; |
| struct work_struct work; |
| bool attached; |
| }; |
| |
| static void cancel_userptr(struct work_struct *work) |
| { |
| struct i915_mmu_object *mo = container_of(work, typeof(*mo), work); |
| struct drm_i915_gem_object *obj = mo->obj; |
| struct work_struct *active; |
| |
| /* Cancel any active worker and force us to re-evaluate gup */ |
| mutex_lock(&obj->mm.lock); |
| active = fetch_and_zero(&obj->userptr.work); |
| mutex_unlock(&obj->mm.lock); |
| if (active) |
| goto out; |
| |
| i915_gem_object_wait(obj, I915_WAIT_ALL, MAX_SCHEDULE_TIMEOUT, NULL); |
| |
| mutex_lock(&obj->base.dev->struct_mutex); |
| |
| /* We are inside a kthread context and can't be interrupted */ |
| if (i915_gem_object_unbind(obj) == 0) |
| __i915_gem_object_put_pages(obj, I915_MM_NORMAL); |
| WARN_ONCE(obj->mm.pages, |
| "Failed to release pages: bind_count=%d, pages_pin_count=%d, pin_display=%d\n", |
| obj->bind_count, |
| atomic_read(&obj->mm.pages_pin_count), |
| obj->pin_display); |
| |
| mutex_unlock(&obj->base.dev->struct_mutex); |
| |
| out: |
| i915_gem_object_put(obj); |
| } |
| |
| static void add_object(struct i915_mmu_object *mo) |
| { |
| if (mo->attached) |
| return; |
| |
| interval_tree_insert(&mo->it, &mo->mn->objects); |
| mo->attached = true; |
| } |
| |
| static void del_object(struct i915_mmu_object *mo) |
| { |
| if (!mo->attached) |
| return; |
| |
| interval_tree_remove(&mo->it, &mo->mn->objects); |
| mo->attached = false; |
| } |
| |
| static void i915_gem_userptr_mn_invalidate_range_start(struct mmu_notifier *_mn, |
| struct mm_struct *mm, |
| unsigned long start, |
| unsigned long end) |
| { |
| struct i915_mmu_notifier *mn = |
| container_of(_mn, struct i915_mmu_notifier, mn); |
| struct i915_mmu_object *mo; |
| struct interval_tree_node *it; |
| LIST_HEAD(cancelled); |
| |
| if (RB_EMPTY_ROOT(&mn->objects.rb_root)) |
| return; |
| |
| /* interval ranges are inclusive, but invalidate range is exclusive */ |
| end--; |
| |
| spin_lock(&mn->lock); |
| it = interval_tree_iter_first(&mn->objects, start, end); |
| while (it) { |
| /* 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. |
| */ |
| mo = container_of(it, struct i915_mmu_object, it); |
| if (kref_get_unless_zero(&mo->obj->base.refcount)) |
| queue_work(mn->wq, &mo->work); |
| |
| list_add(&mo->link, &cancelled); |
| it = interval_tree_iter_next(it, start, end); |
| } |
| list_for_each_entry(mo, &cancelled, link) |
| del_object(mo); |
| spin_unlock(&mn->lock); |
| |
| if (!list_empty(&cancelled)) |
| flush_workqueue(mn->wq); |
| } |
| |
| static const struct mmu_notifier_ops i915_gem_userptr_notifier = { |
| .invalidate_range_start = i915_gem_userptr_mn_invalidate_range_start, |
| }; |
| |
| static struct i915_mmu_notifier * |
| i915_mmu_notifier_create(struct mm_struct *mm) |
| { |
| struct i915_mmu_notifier *mn; |
| int ret; |
| |
| 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->wq = alloc_workqueue("i915-userptr-release", WQ_UNBOUND, 0); |
| if (mn->wq == NULL) { |
| kfree(mn); |
| return ERR_PTR(-ENOMEM); |
| } |
| |
| /* Protected by mmap_sem (write-lock) */ |
| ret = __mmu_notifier_register(&mn->mn, mm); |
| if (ret) { |
| destroy_workqueue(mn->wq); |
| kfree(mn); |
| return ERR_PTR(ret); |
| } |
| |
| return mn; |
| } |
| |
| static void |
| i915_gem_userptr_release__mmu_notifier(struct drm_i915_gem_object *obj) |
| { |
| struct i915_mmu_object *mo; |
| |
| mo = obj->userptr.mmu_object; |
| if (mo == NULL) |
| return; |
| |
| spin_lock(&mo->mn->lock); |
| del_object(mo); |
| spin_unlock(&mo->mn->lock); |
| kfree(mo); |
| |
| obj->userptr.mmu_object = NULL; |
| } |
| |
| static struct i915_mmu_notifier * |
| i915_mmu_notifier_find(struct i915_mm_struct *mm) |
| { |
| struct i915_mmu_notifier *mn = mm->mn; |
| |
| mn = mm->mn; |
| if (mn) |
| return mn; |
| |
| down_write(&mm->mm->mmap_sem); |
| mutex_lock(&mm->i915->mm_lock); |
| if ((mn = mm->mn) == NULL) { |
| mn = i915_mmu_notifier_create(mm->mm); |
| if (!IS_ERR(mn)) |
| mm->mn = mn; |
| } |
| mutex_unlock(&mm->i915->mm_lock); |
| up_write(&mm->mm->mmap_sem); |
| |
| return 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 == NULL) |
| return -ENOMEM; |
| |
| mo->mn = mn; |
| mo->obj = obj; |
| mo->it.start = obj->userptr.ptr; |
| mo->it.last = obj->userptr.ptr + obj->base.size - 1; |
| INIT_WORK(&mo->work, cancel_userptr); |
| |
| 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); |
| destroy_workqueue(mn->wq); |
| kfree(mn); |
| } |
| |
| #else |
| |
| 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; |
| }; |
| |
| #if IS_ENABLED(CONFIG_SWIOTLB) |
| #define swiotlb_active() swiotlb_nr_tbl() |
| #else |
| #define swiotlb_active() 0 |
| #endif |
| |
| static int |
| st_set_pages(struct sg_table **st, struct page **pvec, int num_pages) |
| { |
| struct scatterlist *sg; |
| int ret, n; |
| |
| *st = kmalloc(sizeof(**st), GFP_KERNEL); |
| if (*st == NULL) |
| return -ENOMEM; |
| |
| if (swiotlb_active()) { |
| ret = sg_alloc_table(*st, num_pages, GFP_KERNEL); |
| if (ret) |
| goto err; |
| |
| for_each_sg((*st)->sgl, sg, num_pages, n) |
| sg_set_page(sg, pvec[n], PAGE_SIZE, 0); |
| } else { |
| ret = sg_alloc_table_from_pages(*st, pvec, num_pages, |
| 0, num_pages << PAGE_SHIFT, |
| GFP_KERNEL); |
| if (ret) |
| goto err; |
| } |
| |
| return 0; |
| |
| err: |
| kfree(*st); |
| *st = NULL; |
| return ret; |
| } |
| |
| static struct sg_table * |
| __i915_gem_userptr_set_pages(struct drm_i915_gem_object *obj, |
| struct page **pvec, int num_pages) |
| { |
| struct sg_table *pages; |
| int ret; |
| |
| ret = st_set_pages(&pages, pvec, num_pages); |
| if (ret) |
| return ERR_PTR(ret); |
| |
| ret = i915_gem_gtt_prepare_pages(obj, pages); |
| if (ret) { |
| sg_free_table(pages); |
| kfree(pages); |
| return ERR_PTR(ret); |
| } |
| |
| return pages; |
| } |
| |
| static int |
| __i915_gem_userptr_set_active(struct drm_i915_gem_object *obj, |
| bool value) |
| { |
| int ret = 0; |
| |
| /* 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 defined(CONFIG_MMU_NOTIFIER) |
| if (obj->userptr.mmu_object == NULL) |
| return 0; |
| |
| spin_lock(&obj->userptr.mmu_object->mn->lock); |
| /* In order to serialise get_pages with an outstanding |
| * cancel_userptr, we must drop the struct_mutex and try again. |
| */ |
| if (!value) |
| del_object(obj->userptr.mmu_object); |
| else if (!work_pending(&obj->userptr.mmu_object->work)) |
| add_object(obj->userptr.mmu_object); |
| else |
| ret = -EAGAIN; |
| spin_unlock(&obj->userptr.mmu_object->mn->lock); |
| #endif |
| |
| return ret; |
| } |
| |
| 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 int npages = obj->base.size >> PAGE_SHIFT; |
| struct page **pvec; |
| int pinned, 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; |
| |
| if (!obj->userptr.read_only) |
| flags |= FOLL_WRITE; |
| |
| ret = -EFAULT; |
| if (mmget_not_zero(mm)) { |
| down_read(&mm->mmap_sem); |
| while (pinned < npages) { |
| ret = get_user_pages_remote |
| (work->task, mm, |
| obj->userptr.ptr + pinned * PAGE_SIZE, |
| npages - pinned, |
| flags, |
| pvec + pinned, NULL, NULL); |
| if (ret < 0) |
| break; |
| |
| pinned += ret; |
| } |
| up_read(&mm->mmap_sem); |
| mmput(mm); |
| } |
| } |
| |
| mutex_lock(&obj->mm.lock); |
| if (obj->userptr.work == &work->work) { |
| struct sg_table *pages = ERR_PTR(ret); |
| |
| if (pinned == npages) { |
| pages = __i915_gem_userptr_set_pages(obj, pvec, npages); |
| if (!IS_ERR(pages)) { |
| __i915_gem_object_set_pages(obj, 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); |
| |
| release_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_sem, and we have |
| * a strict lock ordering of mmap_sem, 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 struct sg_table * |
| i915_gem_userptr_get_pages(struct drm_i915_gem_object *obj) |
| { |
| const int 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; |
| |
| /* 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 ERR_CAST(obj->userptr.work); |
| else |
| return ERR_PTR(-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 */ |
| pinned = __get_user_pages_fast(obj->userptr.ptr, |
| num_pages, |
| !obj->userptr.read_only, |
| 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_set_pages(obj, pvec, num_pages); |
| active = !IS_ERR(pages); |
| } |
| if (active) |
| __i915_gem_userptr_set_active(obj, true); |
| |
| if (IS_ERR(pages)) |
| release_pages(pvec, pinned); |
| kvfree(pvec); |
| |
| return 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; |
| |
| BUG_ON(obj->userptr.work != NULL); |
| __i915_gem_userptr_set_active(obj, false); |
| |
| if (obj->mm.madv != I915_MADV_WILLNEED) |
| obj->mm.dirty = false; |
| |
| i915_gem_gtt_finish_pages(obj, pages); |
| |
| for_each_sgt_page(page, sgt_iter, pages) { |
| if (obj->mm.dirty) |
| set_page_dirty(page); |
| |
| mark_page_accessed(page); |
| put_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, |
| .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) |
| { |
| 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; |
| |
| if (offset_in_page(args->user_ptr | args->user_size)) |
| return -EINVAL; |
| |
| if (!access_ok(args->flags & I915_USERPTR_READ_ONLY ? VERIFY_READ : VERIFY_WRITE, |
| (char __user *)(unsigned long)args->user_ptr, args->user_size)) |
| return -EFAULT; |
| |
| if (args->flags & I915_USERPTR_READ_ONLY) { |
| /* On almost all of the current hw, we cannot tell the GPU that a |
| * page is readonly, so this is just a placeholder in the uAPI. |
| */ |
| return -ENODEV; |
| } |
| |
| obj = i915_gem_object_alloc(dev_priv); |
| 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); |
| obj->base.read_domains = I915_GEM_DOMAIN_CPU; |
| obj->base.write_domain = I915_GEM_DOMAIN_CPU; |
| i915_gem_object_set_cache_coherency(obj, I915_CACHE_LLC); |
| |
| obj->userptr.ptr = args->user_ptr; |
| obj->userptr.read_only = !!(args->flags & I915_USERPTR_READ_ONLY); |
| |
| /* 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, 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); |
| } |