diff options
Diffstat (limited to 'drivers/gpu/drm/i915/i915_gem_userptr.c')
| -rw-r--r-- | drivers/gpu/drm/i915/i915_gem_userptr.c | 711 |
1 files changed, 711 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_gem_userptr.c b/drivers/gpu/drm/i915/i915_gem_userptr.c new file mode 100644 index 000000000000..21ea92886a56 --- /dev/null +++ b/drivers/gpu/drm/i915/i915_gem_userptr.c @@ -0,0 +1,711 @@ +/* + * 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 "drmP.h" +#include "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> + +#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 objects; + struct drm_device *dev; + struct mm_struct *mm; + struct work_struct work; + unsigned long count; + unsigned long serial; +}; + +struct i915_mmu_object { + struct i915_mmu_notifier *mmu; + struct interval_tree_node it; + struct drm_i915_gem_object *obj; +}; + +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 interval_tree_node *it = NULL; + unsigned long serial = 0; + + end--; /* interval ranges are inclusive, but invalidate range is exclusive */ + while (start < end) { + struct drm_i915_gem_object *obj; + + obj = NULL; + spin_lock(&mn->lock); + if (serial == mn->serial) + it = interval_tree_iter_next(it, start, end); + else + it = interval_tree_iter_first(&mn->objects, start, end); + if (it != NULL) { + obj = container_of(it, struct i915_mmu_object, it)->obj; + drm_gem_object_reference(&obj->base); + serial = mn->serial; + } + spin_unlock(&mn->lock); + if (obj == NULL) + return; + + mutex_lock(&mn->dev->struct_mutex); + /* Cancel any active worker and force us to re-evaluate gup */ + obj->userptr.work = NULL; + + if (obj->pages != NULL) { + struct drm_i915_private *dev_priv = to_i915(mn->dev); + struct i915_vma *vma, *tmp; + bool was_interruptible; + + was_interruptible = dev_priv->mm.interruptible; + dev_priv->mm.interruptible = false; + + list_for_each_entry_safe(vma, tmp, &obj->vma_list, vma_link) { + int ret = i915_vma_unbind(vma); + WARN_ON(ret && ret != -EIO); + } + WARN_ON(i915_gem_object_put_pages(obj)); + + dev_priv->mm.interruptible = was_interruptible; + } + + start = obj->userptr.ptr + obj->base.size; + + drm_gem_object_unreference(&obj->base); + mutex_unlock(&mn->dev->struct_mutex); + } +} + +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_lookup(struct drm_device *dev, struct mm_struct *mm) +{ + struct drm_i915_private *dev_priv = to_i915(dev); + struct i915_mmu_notifier *mmu; + + /* Protected by dev->struct_mutex */ + hash_for_each_possible(dev_priv->mmu_notifiers, mmu, node, (unsigned long)mm) + if (mmu->mm == mm) + return mmu; + + return NULL; +} + +static struct i915_mmu_notifier * +i915_mmu_notifier_get(struct drm_device *dev, struct mm_struct *mm) +{ + struct drm_i915_private *dev_priv = to_i915(dev); + struct i915_mmu_notifier *mmu; + int ret; + + lockdep_assert_held(&dev->struct_mutex); + + mmu = __i915_mmu_notifier_lookup(dev, mm); + if (mmu) + return mmu; + + mmu = kmalloc(sizeof(*mmu), GFP_KERNEL); + if (mmu == NULL) + return ERR_PTR(-ENOMEM); + + spin_lock_init(&mmu->lock); + mmu->dev = dev; + mmu->mn.ops = &i915_gem_userptr_notifier; + mmu->mm = mm; + mmu->objects = RB_ROOT; + mmu->count = 0; + mmu->serial = 0; + + /* Protected by mmap_sem (write-lock) */ + ret = __mmu_notifier_register(&mmu->mn, mm); + if (ret) { + kfree(mmu); + return ERR_PTR(ret); + } + + /* Protected by dev->struct_mutex */ + hash_add(dev_priv->mmu_notifiers, &mmu->node, (unsigned long)mm); + return mmu; +} + +static void +__i915_mmu_notifier_destroy_worker(struct work_struct *work) +{ + struct i915_mmu_notifier *mmu = container_of(work, typeof(*mmu), work); + mmu_notifier_unregister(&mmu->mn, mmu->mm); + kfree(mmu); +} + +static void +__i915_mmu_notifier_destroy(struct i915_mmu_notifier *mmu) +{ + lockdep_assert_held(&mmu->dev->struct_mutex); + + /* Protected by dev->struct_mutex */ + hash_del(&mmu->node); + + /* Our lock ordering is: mmap_sem, mmu_notifier_scru, struct_mutex. + * We enter the function holding struct_mutex, therefore we need + * to drop our mutex prior to calling mmu_notifier_unregister in + * order to prevent lock inversion (and system-wide deadlock) + * between the mmap_sem and struct-mutex. Hence we defer the + * unregistration to a workqueue where we hold no locks. + */ + INIT_WORK(&mmu->work, __i915_mmu_notifier_destroy_worker); + schedule_work(&mmu->work); +} + +static void __i915_mmu_notifier_update_serial(struct i915_mmu_notifier *mmu) +{ + if (++mmu->serial == 0) + mmu->serial = 1; +} + +static void +i915_mmu_notifier_del(struct i915_mmu_notifier *mmu, + struct i915_mmu_object *mn) +{ + lockdep_assert_held(&mmu->dev->struct_mutex); + + spin_lock(&mmu->lock); + interval_tree_remove(&mn->it, &mmu->objects); + __i915_mmu_notifier_update_serial(mmu); + spin_unlock(&mmu->lock); + + /* Protected against _add() by dev->struct_mutex */ + if (--mmu->count == 0) + __i915_mmu_notifier_destroy(mmu); +} + +static int +i915_mmu_notifier_add(struct i915_mmu_notifier *mmu, + struct i915_mmu_object *mn) +{ + struct interval_tree_node *it; + int ret; + + ret = i915_mutex_lock_interruptible(mmu->dev); + if (ret) + return ret; + + /* Make sure we drop the final active reference (and thereby + * remove the objects from the interval tree) before we do + * the check for overlapping objects. + */ + i915_gem_retire_requests(mmu->dev); + + /* Disallow overlapping userptr objects */ + spin_lock(&mmu->lock); + it = interval_tree_iter_first(&mmu->objects, + mn->it.start, mn->it.last); + if (it) { + struct drm_i915_gem_object *obj; + + /* We only need to check the first object in the range as it + * either has cancelled gup work queued and we need to + * return back to the user to give time for the gup-workers + * to flush their object references upon which the object will + * be removed from the interval-tree, or the the range is + * still in use by another client and the overlap is invalid. + */ + + obj = container_of(it, struct i915_mmu_object, it)->obj; + ret = obj->userptr.workers ? -EAGAIN : -EINVAL; + } else { + interval_tree_insert(&mn->it, &mmu->objects); + __i915_mmu_notifier_update_serial(mmu); + ret = 0; + } + spin_unlock(&mmu->lock); + mutex_unlock(&mmu->dev->struct_mutex); + + return ret; +} + +static void +i915_gem_userptr_release__mmu_notifier(struct drm_i915_gem_object *obj) +{ + struct i915_mmu_object *mn; + + mn = obj->userptr.mn; + if (mn == NULL) + return; + + i915_mmu_notifier_del(mn->mmu, mn); + obj->userptr.mn = NULL; +} + +static int +i915_gem_userptr_init__mmu_notifier(struct drm_i915_gem_object *obj, + unsigned flags) +{ + struct i915_mmu_notifier *mmu; + struct i915_mmu_object *mn; + int ret; + + if (flags & I915_USERPTR_UNSYNCHRONIZED) + return capable(CAP_SYS_ADMIN) ? 0 : -EPERM; + + down_write(&obj->userptr.mm->mmap_sem); + ret = i915_mutex_lock_interruptible(obj->base.dev); + if (ret == 0) { + mmu = i915_mmu_notifier_get(obj->base.dev, obj->userptr.mm); + if (!IS_ERR(mmu)) + mmu->count++; /* preemptive add to act as a refcount */ + else + ret = PTR_ERR(mmu); + mutex_unlock(&obj->base.dev->struct_mutex); + } + up_write(&obj->userptr.mm->mmap_sem); + if (ret) + return ret; + + mn = kzalloc(sizeof(*mn), GFP_KERNEL); + if (mn == NULL) { + ret = -ENOMEM; + goto destroy_mmu; + } + + mn->mmu = mmu; + mn->it.start = obj->userptr.ptr; + mn->it.last = mn->it.start + obj->base.size - 1; + mn->obj = obj; + + ret = i915_mmu_notifier_add(mmu, mn); + if (ret) + goto free_mn; + + obj->userptr.mn = mn; + return 0; + +free_mn: + kfree(mn); +destroy_mmu: + mutex_lock(&obj->base.dev->struct_mutex); + if (--mmu->count == 0) + __i915_mmu_notifier_destroy(mmu); + mutex_unlock(&obj->base.dev->struct_mutex); + return ret; +} + +#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; +} +#endif + +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 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; + struct drm_device *dev = obj->base.dev; + const int num_pages = obj->base.size >> PAGE_SHIFT; + struct page **pvec; + int pinned, ret; + + ret = -ENOMEM; + pinned = 0; + + pvec = kmalloc(num_pages*sizeof(struct page *), + GFP_TEMPORARY | __GFP_NOWARN | __GFP_NORETRY); + if (pvec == NULL) + pvec = drm_malloc_ab(num_pages, sizeof(struct page *)); + if (pvec != NULL) { + struct mm_struct *mm = obj->userptr.mm; + + down_read(&mm->mmap_sem); + while (pinned < num_pages) { + ret = get_user_pages(work->task, mm, + obj->userptr.ptr + pinned * PAGE_SIZE, + num_pages - pinned, + !obj->userptr.read_only, 0, + pvec + pinned, NULL); + if (ret < 0) + break; + + pinned += ret; + } + up_read(&mm->mmap_sem); + } + + mutex_lock(&dev->struct_mutex); + if (obj->userptr.work != &work->work) { + ret = 0; + } else if (pinned == num_pages) { + ret = st_set_pages(&obj->pages, pvec, num_pages); + if (ret == 0) { + list_add_tail(&obj->global_list, &to_i915(dev)->mm.unbound_list); + pinned = 0; + } + } + + obj->userptr.work = ERR_PTR(ret); + obj->userptr.workers--; + drm_gem_object_unreference(&obj->base); + mutex_unlock(&dev->struct_mutex); + + release_pages(pvec, pinned, 0); + drm_free_large(pvec); + + put_task_struct(work->task); + kfree(work); +} + +static int +i915_gem_userptr_get_pages(struct drm_i915_gem_object *obj) +{ + const int num_pages = obj->base.size >> PAGE_SHIFT; + struct page **pvec; + int pinned, ret; + + /* 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. + */ + + pvec = NULL; + pinned = 0; + if (obj->userptr.mm == current->mm) { + pvec = kmalloc(num_pages*sizeof(struct page *), + GFP_TEMPORARY | __GFP_NOWARN | __GFP_NORETRY); + if (pvec == NULL) { + pvec = drm_malloc_ab(num_pages, sizeof(struct page *)); + if (pvec == NULL) + return -ENOMEM; + } + + pinned = __get_user_pages_fast(obj->userptr.ptr, num_pages, + !obj->userptr.read_only, pvec); + } + if (pinned < num_pages) { + if (pinned < 0) { + ret = pinned; + pinned = 0; + } else { + /* 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. + */ + ret = -EAGAIN; + if (obj->userptr.work == NULL && + obj->userptr.workers < I915_GEM_USERPTR_MAX_WORKERS) { + struct get_pages_work *work; + + work = kmalloc(sizeof(*work), GFP_KERNEL); + if (work != NULL) { + obj->userptr.work = &work->work; + obj->userptr.workers++; + + work->obj = obj; + drm_gem_object_reference(&obj->base); + + work->task = current; + get_task_struct(work->task); + + INIT_WORK(&work->work, __i915_gem_userptr_get_pages_worker); + schedule_work(&work->work); + } else + ret = -ENOMEM; + } else { + if (IS_ERR(obj->userptr.work)) { + ret = PTR_ERR(obj->userptr.work); + obj->userptr.work = NULL; + } + } + } + } else { + ret = st_set_pages(&obj->pages, pvec, num_pages); + if (ret == 0) { + obj->userptr.work = NULL; + pinned = 0; + } + } + + release_pages(pvec, pinned, 0); + drm_free_large(pvec); + return ret; +} + +static void +i915_gem_userptr_put_pages(struct drm_i915_gem_object *obj) +{ + struct scatterlist *sg; + int i; + + BUG_ON(obj->userptr.work != NULL); + + if (obj->madv != I915_MADV_WILLNEED) + obj->dirty = 0; + + for_each_sg(obj->pages->sgl, sg, obj->pages->nents, i) { + struct page *page = sg_page(sg); + + if (obj->dirty) + set_page_dirty(page); + + mark_page_accessed(page); + page_cache_release(page); + } + obj->dirty = 0; + + sg_free_table(obj->pages); + kfree(obj->pages); +} + +static void +i915_gem_userptr_release(struct drm_i915_gem_object *obj) +{ + i915_gem_userptr_release__mmu_notifier(obj); + + if (obj->userptr.mm) { + mmput(obj->userptr.mm); + obj->userptr.mm = NULL; + } +} + +static int +i915_gem_userptr_dmabuf_export(struct drm_i915_gem_object *obj) +{ + if (obj->userptr.mn) + return 0; + + return i915_gem_userptr_init__mmu_notifier(obj, 0); +} + +static const struct drm_i915_gem_object_ops i915_gem_userptr_ops = { + .dmabuf_export = i915_gem_userptr_dmabuf_export, + .get_pages = i915_gem_userptr_get_pages, + .put_pages = i915_gem_userptr_put_pages, + .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 cannot overlap any other userptr object in the same address space. + * 3. 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). + * 4. 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. + * 5. 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. + * + * 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 = dev->dev_private; + struct drm_i915_gem_userptr *args = data; + struct drm_i915_gem_object *obj; + int ret; + u32 handle; + + 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 (args->user_size > dev_priv->gtt.base.total) + return -E2BIG; + + 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; + } + + /* Allocate the new object */ + obj = i915_gem_object_alloc(dev); + 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->cache_level = I915_CACHE_LLC; + obj->base.write_domain = I915_GEM_DOMAIN_CPU; + obj->base.read_domains = I915_GEM_DOMAIN_CPU; + + 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 = -ENOMEM; + if ((obj->userptr.mm = get_task_mm(current))) + 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 */ + drm_gem_object_unreference_unlocked(&obj->base); + if (ret) + return ret; + + args->handle = handle; + return 0; +} + +int +i915_gem_init_userptr(struct drm_device *dev) +{ +#if defined(CONFIG_MMU_NOTIFIER) + struct drm_i915_private *dev_priv = to_i915(dev); + hash_init(dev_priv->mmu_notifiers); +#endif + return 0; +} |