i915_gem.c

/*
 * Copyright © 2008-2015 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 <drm/drm_vma_manager.h>
#include <drm/i915_drm.h>
#include <linux/dma-fence-array.h>
#include <linux/kthread.h>
#include <linux/reservation.h>
#include <linux/shmem_fs.h>
#include <linux/slab.h>
#include <linux/stop_machine.h>
#include <linux/swap.h>
#include <linux/pci.h>
#include <linux/dma-buf.h>
#include <linux/mman.h>

#include "gem/i915_gem_clflush.h"
#include "gem/i915_gem_context.h"
#include "gem/i915_gem_ioctls.h"
#include "gem/i915_gem_pm.h"
#include "gem/i915_gemfs.h"
#include "gt/intel_engine_pm.h"
#include "gt/intel_gt_pm.h"
#include "gt/intel_mocs.h"
#include "gt/intel_reset.h"
#include "gt/intel_workarounds.h"

#include "i915_drv.h"
#include "i915_trace.h"
#include "i915_vgpu.h"

#include "intel_display.h"
#include "intel_drv.h"
#include "intel_frontbuffer.h"
#include "intel_pm.h"

static int
insert_mappable_node(struct i915_ggtt *ggtt,
                     struct drm_mm_node *node, u32 size)
{
	memset(node, 0, sizeof(*node));
	return drm_mm_insert_node_in_range(&ggtt->vm.mm, node,
					   size, 0, I915_COLOR_UNEVICTABLE,
					   0, ggtt->mappable_end,
					   DRM_MM_INSERT_LOW);
}

static void
remove_mappable_node(struct drm_mm_node *node)
{
	drm_mm_remove_node(node);
}

int
i915_gem_get_aperture_ioctl(struct drm_device *dev, void *data,
			    struct drm_file *file)
{
	struct i915_ggtt *ggtt = &to_i915(dev)->ggtt;
	struct drm_i915_gem_get_aperture *args = data;
	struct i915_vma *vma;
	u64 pinned;

	mutex_lock(&ggtt->vm.mutex);

	pinned = ggtt->vm.reserved;
	list_for_each_entry(vma, &ggtt->vm.bound_list, vm_link)
		if (i915_vma_is_pinned(vma))
			pinned += vma->node.size;

	mutex_unlock(&ggtt->vm.mutex);

	args->aper_size = ggtt->vm.total;
	args->aper_available_size = args->aper_size - pinned;

	return 0;
}

int i915_gem_object_unbind(struct drm_i915_gem_object *obj)
{
	struct i915_vma *vma;
	LIST_HEAD(still_in_list);
	int ret;

	lockdep_assert_held(&obj->base.dev->struct_mutex);

	/* Closed vma are removed from the obj->vma_list - but they may
	 * still have an active binding on the object. To remove those we
	 * must wait for all rendering to complete to the object (as unbinding
	 * must anyway), and retire the requests.
	 */
	ret = i915_gem_object_set_to_cpu_domain(obj, false);
	if (ret)
		return ret;

	spin_lock(&obj->vma.lock);
	while (!ret && (vma = list_first_entry_or_null(&obj->vma.list,
						       struct i915_vma,
						       obj_link))) {
		list_move_tail(&vma->obj_link, &still_in_list);
		spin_unlock(&obj->vma.lock);

		ret = i915_vma_unbind(vma);

		spin_lock(&obj->vma.lock);
	}
	list_splice(&still_in_list, &obj->vma.list);
	spin_unlock(&obj->vma.lock);

	return ret;
}

static long
i915_gem_object_wait_fence(struct dma_fence *fence,
			   unsigned int flags,
			   long timeout)
{
	struct i915_request *rq;

	BUILD_BUG_ON(I915_WAIT_INTERRUPTIBLE != 0x1);

	if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags))
		return timeout;

	if (!dma_fence_is_i915(fence))
		return dma_fence_wait_timeout(fence,
					      flags & I915_WAIT_INTERRUPTIBLE,
					      timeout);

	rq = to_request(fence);
	if (i915_request_completed(rq))
		goto out;

	timeout = i915_request_wait(rq, flags, timeout);

out:
	if (flags & I915_WAIT_LOCKED && i915_request_completed(rq))
		i915_request_retire_upto(rq);

	return timeout;
}

static long
i915_gem_object_wait_reservation(struct reservation_object *resv,
				 unsigned int flags,
				 long timeout)
{
	unsigned int seq = __read_seqcount_begin(&resv->seq);
	struct dma_fence *excl;
	bool prune_fences = false;

	if (flags & I915_WAIT_ALL) {
		struct dma_fence **shared;
		unsigned int count, i;
		int ret;

		ret = reservation_object_get_fences_rcu(resv,
							&excl, &count, &shared);
		if (ret)
			return ret;

		for (i = 0; i < count; i++) {
			timeout = i915_gem_object_wait_fence(shared[i],
							     flags, timeout);
			if (timeout < 0)
				break;

			dma_fence_put(shared[i]);
		}

		for (; i < count; i++)
			dma_fence_put(shared[i]);
		kfree(shared);

		/*
		 * If both shared fences and an exclusive fence exist,
		 * then by construction the shared fences must be later
		 * than the exclusive fence. If we successfully wait for
		 * all the shared fences, we know that the exclusive fence
		 * must all be signaled. If all the shared fences are
		 * signaled, we can prune the array and recover the
		 * floating references on the fences/requests.
		 */
		prune_fences = count && timeout >= 0;
	} else {
		excl = reservation_object_get_excl_rcu(resv);
	}

	if (excl && timeout >= 0)
		timeout = i915_gem_object_wait_fence(excl, flags, timeout);

	dma_fence_put(excl);

	/*
	 * Opportunistically prune the fences iff we know they have *all* been
	 * signaled and that the reservation object has not been changed (i.e.
	 * no new fences have been added).
	 */
	if (prune_fences && !__read_seqcount_retry(&resv->seq, seq)) {
		if (reservation_object_trylock(resv)) {
			if (!__read_seqcount_retry(&resv->seq, seq))
				reservation_object_add_excl_fence(resv, NULL);
			reservation_object_unlock(resv);
		}
	}

	return timeout;
}

static void __fence_set_priority(struct dma_fence *fence,
				 const struct i915_sched_attr *attr)
{
	struct i915_request *rq;
	struct intel_engine_cs *engine;

	if (dma_fence_is_signaled(fence) || !dma_fence_is_i915(fence))
		return;

	rq = to_request(fence);
	engine = rq->engine;

	local_bh_disable();
	rcu_read_lock(); /* RCU serialisation for set-wedged protection */
	if (engine->schedule)
		engine->schedule(rq, attr);
	rcu_read_unlock();
	local_bh_enable(); /* kick the tasklets if queues were reprioritised */
}

static void fence_set_priority(struct dma_fence *fence,
			       const struct i915_sched_attr *attr)
{
	/* Recurse once into a fence-array */
	if (dma_fence_is_array(fence)) {
		struct dma_fence_array *array = to_dma_fence_array(fence);
		int i;

		for (i = 0; i < array->num_fences; i++)
			__fence_set_priority(array->fences[i], attr);
	} else {
		__fence_set_priority(fence, attr);
	}
}

int
i915_gem_object_wait_priority(struct drm_i915_gem_object *obj,
			      unsigned int flags,
			      const struct i915_sched_attr *attr)
{
	struct dma_fence *excl;

	if (flags & I915_WAIT_ALL) {
		struct dma_fence **shared;
		unsigned int count, i;
		int ret;

		ret = reservation_object_get_fences_rcu(obj->resv,
							&excl, &count, &shared);
		if (ret)
			return ret;

		for (i = 0; i < count; i++) {
			fence_set_priority(shared[i], attr);
			dma_fence_put(shared[i]);
		}

		kfree(shared);
	} else {
		excl = reservation_object_get_excl_rcu(obj->resv);
	}

	if (excl) {
		fence_set_priority(excl, attr);
		dma_fence_put(excl);
	}
	return 0;
}

/**
 * Waits for rendering to the object to be completed
 * @obj: i915 gem object
 * @flags: how to wait (under a lock, for all rendering or just for writes etc)
 * @timeout: how long to wait
 */
int
i915_gem_object_wait(struct drm_i915_gem_object *obj,
		     unsigned int flags,
		     long timeout)
{
	might_sleep();
	GEM_BUG_ON(timeout < 0);

	timeout = i915_gem_object_wait_reservation(obj->resv, flags, timeout);
	return timeout < 0 ? timeout : 0;
}

static int
i915_gem_phys_pwrite(struct drm_i915_gem_object *obj,
		     struct drm_i915_gem_pwrite *args,
		     struct drm_file *file)
{
	void *vaddr = obj->phys_handle->vaddr + args->offset;
	char __user *user_data = u64_to_user_ptr(args->data_ptr);

	/* We manually control the domain here and pretend that it
	 * remains coherent i.e. in the GTT domain, like shmem_pwrite.
	 */
	intel_fb_obj_invalidate(obj, ORIGIN_CPU);
	if (copy_from_user(vaddr, user_data, args->size))
		return -EFAULT;

	drm_clflush_virt_range(vaddr, args->size);
	i915_gem_chipset_flush(to_i915(obj->base.dev));

	intel_fb_obj_flush(obj, ORIGIN_CPU);
	return 0;
}

static int
i915_gem_create(struct drm_file *file,
		struct drm_i915_private *dev_priv,
		u64 *size_p,
		u32 *handle_p)
{
	struct drm_i915_gem_object *obj;
	u32 handle;
	u64 size;
	int ret;

	size = round_up(*size_p, PAGE_SIZE);
	if (size == 0)
		return -EINVAL;

	/* Allocate the new object */
	obj = i915_gem_object_create_shmem(dev_priv, size);
	if (IS_ERR(obj))
		return PTR_ERR(obj);

	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;

	*handle_p = handle;
	*size_p = size;
	return 0;
}

int
i915_gem_dumb_create(struct drm_file *file,
		     struct drm_device *dev,
		     struct drm_mode_create_dumb *args)
{
	int cpp = DIV_ROUND_UP(args->bpp, 8);
	u32 format;

	switch (cpp) {
	case 1:
		format = DRM_FORMAT_C8;
		break;
	case 2:
		format = DRM_FORMAT_RGB565;
		break;
	case 4:
		format = DRM_FORMAT_XRGB8888;
		break;
	default:
		return -EINVAL;
	}

	/* have to work out size/pitch and return them */
	args->pitch = ALIGN(args->width * cpp, 64);

	/* align stride to page size so that we can remap */
	if (args->pitch > intel_plane_fb_max_stride(to_i915(dev), format,
						    DRM_FORMAT_MOD_LINEAR))
		args->pitch = ALIGN(args->pitch, 4096);

	args->size = args->pitch * args->height;
	return i915_gem_create(file, to_i915(dev),
			       &args->size, &args->handle);
}

/**
 * Creates a new mm object and returns a handle to it.
 * @dev: drm device pointer
 * @data: ioctl data blob
 * @file: drm file pointer
 */
int
i915_gem_create_ioctl(struct drm_device *dev, void *data,
		      struct drm_file *file)
{
	struct drm_i915_private *dev_priv = to_i915(dev);
	struct drm_i915_gem_create *args = data;

	i915_gem_flush_free_objects(dev_priv);

	return i915_gem_create(file, dev_priv,
			       &args->size, &args->handle);
}

void i915_gem_flush_ggtt_writes(struct drm_i915_private *dev_priv)
{
	intel_wakeref_t wakeref;

	/*
	 * No actual flushing is required for the GTT write domain for reads
	 * from the GTT domain. Writes to it "immediately" go to main memory
	 * as far as we know, so there's no chipset flush. It also doesn't
	 * land in the GPU render cache.
	 *
	 * However, we do have to enforce the order so that all writes through
	 * the GTT land before any writes to the device, such as updates to
	 * the GATT itself.
	 *
	 * We also have to wait a bit for the writes to land from the GTT.
	 * An uncached read (i.e. mmio) seems to be ideal for the round-trip
	 * timing. This issue has only been observed when switching quickly
	 * between GTT writes and CPU reads from inside the kernel on recent hw,
	 * and it appears to only affect discrete GTT blocks (i.e. on LLC
	 * system agents we cannot reproduce this behaviour, until Cannonlake
	 * that was!).
	 */

	wmb();

	if (INTEL_INFO(dev_priv)->has_coherent_ggtt)
		return;

	i915_gem_chipset_flush(dev_priv);

	with_intel_runtime_pm(dev_priv, wakeref) {
		spin_lock_irq(&dev_priv->uncore.lock);

		POSTING_READ_FW(RING_HEAD(RENDER_RING_BASE));

		spin_unlock_irq(&dev_priv->uncore.lock);
	}
}

static int
shmem_pread(struct page *page, int offset, int len, char __user *user_data,
	    bool needs_clflush)
{
	char *vaddr;
	int ret;

	vaddr = kmap(page);

	if (needs_clflush)
		drm_clflush_virt_range(vaddr + offset, len);

	ret = __copy_to_user(user_data, vaddr + offset, len);

	kunmap(page);

	return ret ? -EFAULT : 0;
}

static int
i915_gem_shmem_pread(struct drm_i915_gem_object *obj,
		     struct drm_i915_gem_pread *args)
{
	char __user *user_data;
	u64 remain;
	unsigned int needs_clflush;
	unsigned int idx, offset;
	int ret;

	ret = mutex_lock_interruptible(&obj->base.dev->struct_mutex);
	if (ret)
		return ret;

	ret = i915_gem_object_prepare_read(obj, &needs_clflush);
	mutex_unlock(&obj->base.dev->struct_mutex);
	if (ret)
		return ret;

	remain = args->size;
	user_data = u64_to_user_ptr(args->data_ptr);
	offset = offset_in_page(args->offset);
	for (idx = args->offset >> PAGE_SHIFT; remain; idx++) {
		struct page *page = i915_gem_object_get_page(obj, idx);
		unsigned int length = min_t(u64, remain, PAGE_SIZE - offset);

		ret = shmem_pread(page, offset, length, user_data,
				  needs_clflush);
		if (ret)
			break;

		remain -= length;
		user_data += length;
		offset = 0;
	}

	i915_gem_object_finish_access(obj);
	return ret;
}

static inline bool
gtt_user_read(struct io_mapping *mapping,
	      loff_t base, int offset,
	      char __user *user_data, int length)
{
	void __iomem *vaddr;
	unsigned long unwritten;

	/* We can use the cpu mem copy function because this is X86. */
	vaddr = io_mapping_map_atomic_wc(mapping, base);
	unwritten = __copy_to_user_inatomic(user_data,
					    (void __force *)vaddr + offset,
					    length);
	io_mapping_unmap_atomic(vaddr);
	if (unwritten) {
		vaddr = io_mapping_map_wc(mapping, base, PAGE_SIZE);
		unwritten = copy_to_user(user_data,
					 (void __force *)vaddr + offset,
					 length);
		io_mapping_unmap(vaddr);
	}
	return unwritten;
}

static int
i915_gem_gtt_pread(struct drm_i915_gem_object *obj,
		   const struct drm_i915_gem_pread *args)
{
	struct drm_i915_private *i915 = to_i915(obj->base.dev);
	struct i915_ggtt *ggtt = &i915->ggtt;
	intel_wakeref_t wakeref;
	struct drm_mm_node node;
	struct i915_vma *vma;
	void __user *user_data;
	u64 remain, offset;
	int ret;

	ret = mutex_lock_interruptible(&i915->drm.struct_mutex);
	if (ret)
		return ret;

	wakeref = intel_runtime_pm_get(i915);
	vma = i915_gem_object_ggtt_pin(obj, NULL, 0, 0,
				       PIN_MAPPABLE |
				       PIN_NONFAULT |
				       PIN_NONBLOCK);
	if (!IS_ERR(vma)) {
		node.start = i915_ggtt_offset(vma);
		node.allocated = false;
		ret = i915_vma_put_fence(vma);
		if (ret) {
			i915_vma_unpin(vma);
			vma = ERR_PTR(ret);
		}
	}
	if (IS_ERR(vma)) {
		ret = insert_mappable_node(ggtt, &node, PAGE_SIZE);
		if (ret)
			goto out_unlock;
		GEM_BUG_ON(!node.allocated);
	}

	ret = i915_gem_object_set_to_gtt_domain(obj, false);
	if (ret)
		goto out_unpin;

	mutex_unlock(&i915->drm.struct_mutex);

	user_data = u64_to_user_ptr(args->data_ptr);
	remain = args->size;
	offset = args->offset;

	while (remain > 0) {
		/* Operation in this page
		 *
		 * page_base = page offset within aperture
		 * page_offset = offset within page
		 * page_length = bytes to copy for this page
		 */
		u32 page_base = node.start;
		unsigned page_offset = offset_in_page(offset);
		unsigned page_length = PAGE_SIZE - page_offset;
		page_length = remain < page_length ? remain : page_length;
		if (node.allocated) {
			wmb();
			ggtt->vm.insert_page(&ggtt->vm,
					     i915_gem_object_get_dma_address(obj, offset >> PAGE_SHIFT),
					     node.start, I915_CACHE_NONE, 0);
			wmb();
		} else {
			page_base += offset & PAGE_MASK;
		}

		if (gtt_user_read(&ggtt->iomap, page_base, page_offset,
				  user_data, page_length)) {
			ret = -EFAULT;
			break;
		}

		remain -= page_length;
		user_data += page_length;
		offset += page_length;
	}

	mutex_lock(&i915->drm.struct_mutex);
out_unpin:
	if (node.allocated) {
		wmb();
		ggtt->vm.clear_range(&ggtt->vm, node.start, node.size);
		remove_mappable_node(&node);
	} else {
		i915_vma_unpin(vma);
	}
out_unlock:
	intel_runtime_pm_put(i915, wakeref);
	mutex_unlock(&i915->drm.struct_mutex);

	return ret;
}

/**
 * Reads data from the object referenced by handle.
 * @dev: drm device pointer
 * @data: ioctl data blob
 * @file: drm file pointer
 *
 * On error, the contents of *data are undefined.
 */
int
i915_gem_pread_ioctl(struct drm_device *dev, void *data,
		     struct drm_file *file)
{
	struct drm_i915_gem_pread *args = data;
	struct drm_i915_gem_object *obj;
	int ret;

	if (args->size == 0)
		return 0;

	if (!access_ok(u64_to_user_ptr(args->data_ptr),
		       args->size))
		return -EFAULT;

	obj = i915_gem_object_lookup(file, args->handle);
	if (!obj)
		return -ENOENT;

	/* Bounds check source.  */
	if (range_overflows_t(u64, args->offset, args->size, obj->base.size)) {
		ret = -EINVAL;
		goto out;
	}

	trace_i915_gem_object_pread(obj, args->offset, args->size);

	ret = i915_gem_object_wait(obj,
				   I915_WAIT_INTERRUPTIBLE,
				   MAX_SCHEDULE_TIMEOUT);
	if (ret)
		goto out;

	ret = i915_gem_object_pin_pages(obj);
	if (ret)
		goto out;

	ret = i915_gem_shmem_pread(obj, args);
	if (ret == -EFAULT || ret == -ENODEV)
		ret = i915_gem_gtt_pread(obj, args);

	i915_gem_object_unpin_pages(obj);
out:
	i915_gem_object_put(obj);
	return ret;
}

/* This is the fast write path which cannot handle
 * page faults in the source data
 */

static inline bool
ggtt_write(struct io_mapping *mapping,
	   loff_t base, int offset,
	   char __user *user_data, int length)
{
	void __iomem *vaddr;
	unsigned long unwritten;

	/* We can use the cpu mem copy function because this is X86. */
	vaddr = io_mapping_map_atomic_wc(mapping, base);
	unwritten = __copy_from_user_inatomic_nocache((void __force *)vaddr + offset,
						      user_data, length);
	io_mapping_unmap_atomic(vaddr);
	if (unwritten) {
		vaddr = io_mapping_map_wc(mapping, base, PAGE_SIZE);
		unwritten = copy_from_user((void __force *)vaddr + offset,
					   user_data, length);
		io_mapping_unmap(vaddr);
	}

	return unwritten;
}

/**
 * This is the fast pwrite path, where we copy the data directly from the
 * user into the GTT, uncached.
 * @obj: i915 GEM object
 * @args: pwrite arguments structure
 */
static int
i915_gem_gtt_pwrite_fast(struct drm_i915_gem_object *obj,
			 const struct drm_i915_gem_pwrite *args)
{
	struct drm_i915_private *i915 = to_i915(obj->base.dev);
	struct i915_ggtt *ggtt = &i915->ggtt;
	intel_wakeref_t wakeref;
	struct drm_mm_node node;
	struct i915_vma *vma;
	u64 remain, offset;
	void __user *user_data;
	int ret;

	ret = mutex_lock_interruptible(&i915->drm.struct_mutex);
	if (ret)
		return ret;

	if (i915_gem_object_has_struct_page(obj)) {
		/*
		 * Avoid waking the device up if we can fallback, as
		 * waking/resuming is very slow (worst-case 10-100 ms
		 * depending on PCI sleeps and our own resume time).
		 * This easily dwarfs any performance advantage from
		 * using the cache bypass of indirect GGTT access.
		 */
		wakeref = intel_runtime_pm_get_if_in_use(i915);
		if (!wakeref) {
			ret = -EFAULT;
			goto out_unlock;
		}
	} else {
		/* No backing pages, no fallback, we must force GGTT access */
		wakeref = intel_runtime_pm_get(i915);
	}

	vma = i915_gem_object_ggtt_pin(obj, NULL, 0, 0,
				       PIN_MAPPABLE |
				       PIN_NONFAULT |
				       PIN_NONBLOCK);
	if (!IS_ERR(vma)) {
		node.start = i915_ggtt_offset(vma);
		node.allocated = false;
		ret = i915_vma_put_fence(vma);
		if (ret) {
			i915_vma_unpin(vma);
			vma = ERR_PTR(ret);
		}
	}
	if (IS_ERR(vma)) {
		ret = insert_mappable_node(ggtt, &node, PAGE_SIZE);
		if (ret)
			goto out_rpm;
		GEM_BUG_ON(!node.allocated);
	}

	ret = i915_gem_object_set_to_gtt_domain(obj, true);
	if (ret)
		goto out_unpin;

	mutex_unlock(&i915->drm.struct_mutex);

	intel_fb_obj_invalidate(obj, ORIGIN_CPU);

	user_data = u64_to_user_ptr(args->data_ptr);
	offset = args->offset;
	remain = args->size;
	while (remain) {
		/* Operation in this page
		 *
		 * page_base = page offset within aperture
		 * page_offset = offset within page
		 * page_length = bytes to copy for this page
		 */
		u32 page_base = node.start;
		unsigned int page_offset = offset_in_page(offset);
		unsigned int page_length = PAGE_SIZE - page_offset;
		page_length = remain < page_length ? remain : page_length;
		if (node.allocated) {
			wmb(); /* flush the write before we modify the GGTT */
			ggtt->vm.insert_page(&ggtt->vm,
					     i915_gem_object_get_dma_address(obj, offset >> PAGE_SHIFT),
					     node.start, I915_CACHE_NONE, 0);
			wmb(); /* flush modifications to the GGTT (insert_page) */
		} else {
			page_base += offset & PAGE_MASK;
		}
		/* If we get a fault while copying data, then (presumably) our
		 * source page isn't available.  Return the error and we'll
		 * retry in the slow path.
		 * If the object is non-shmem backed, we retry again with the
		 * path that handles page fault.
		 */
		if (ggtt_write(&ggtt->iomap, page_base, page_offset,
			       user_data, page_length)) {
			ret = -EFAULT;
			break;
		}

		remain -= page_length;
		user_data += page_length;
		offset += page_length;
	}
	intel_fb_obj_flush(obj, ORIGIN_CPU);

	mutex_lock(&i915->drm.struct_mutex);
out_unpin:
	if (node.allocated) {
		wmb();
		ggtt->vm.clear_range(&ggtt->vm, node.start, node.size);
		remove_mappable_node(&node);
	} else {
		i915_vma_unpin(vma);
	}
out_rpm:
	intel_runtime_pm_put(i915, wakeref);
out_unlock:
	mutex_unlock(&i915->drm.struct_mutex);
	return ret;
}

/* Per-page copy function for the shmem pwrite fastpath.
 * Flushes invalid cachelines before writing to the target if
 * needs_clflush_before is set and flushes out any written cachelines after
 * writing if needs_clflush is set.
 */
static int
shmem_pwrite(struct page *page, int offset, int len, char __user *user_data,
	     bool needs_clflush_before,
	     bool needs_clflush_after)
{
	char *vaddr;
	int ret;

	vaddr = kmap(page);

	if (needs_clflush_before)
		drm_clflush_virt_range(vaddr + offset, len);

	ret = __copy_from_user(vaddr + offset, user_data, len);
	if (!ret && needs_clflush_after)
		drm_clflush_virt_range(vaddr + offset, len);

	kunmap(page);

	return ret ? -EFAULT : 0;
}

static int
i915_gem_shmem_pwrite(struct drm_i915_gem_object *obj,
		      const struct drm_i915_gem_pwrite *args)
{
	struct drm_i915_private *i915 = to_i915(obj->base.dev);
	void __user *user_data;
	u64 remain;
	unsigned int partial_cacheline_write;
	unsigned int needs_clflush;
	unsigned int offset, idx;
	int ret;

	ret = mutex_lock_interruptible(&i915->drm.struct_mutex);
	if (ret)
		return ret;

	ret = i915_gem_object_prepare_write(obj, &needs_clflush);
	mutex_unlock(&i915->drm.struct_mutex);
	if (ret)
		return ret;

	/* If we don't overwrite a cacheline completely we need to be
	 * careful to have up-to-date data by first clflushing. Don't
	 * overcomplicate things and flush the entire patch.
	 */
	partial_cacheline_write = 0;
	if (needs_clflush & CLFLUSH_BEFORE)
		partial_cacheline_write = boot_cpu_data.x86_clflush_size - 1;

	user_data = u64_to_user_ptr(args->data_ptr);
	remain = args->size;
	offset = offset_in_page(args->offset);
	for (idx = args->offset >> PAGE_SHIFT; remain; idx++) {
		struct page *page = i915_gem_object_get_page(obj, idx);
		unsigned int length = min_t(u64, remain, PAGE_SIZE - offset);

		ret = shmem_pwrite(page, offset, length, user_data,
				   (offset | length) & partial_cacheline_write,
				   needs_clflush & CLFLUSH_AFTER);
		if (ret)
			break;

		remain -= length;
		user_data += length;
		offset = 0;
	}

	intel_fb_obj_flush(obj, ORIGIN_CPU);
	i915_gem_object_finish_access(obj);
	return ret;
}

/**
 * Writes data to the object referenced by handle.
 * @dev: drm device
 * @data: ioctl data blob
 * @file: drm file
 *
 * On error, the contents of the buffer that were to be modified are undefined.
 */
int
i915_gem_pwrite_ioctl(struct drm_device *dev, void *data,
		      struct drm_file *file)
{
	struct drm_i915_gem_pwrite *args = data;
	struct drm_i915_gem_object *obj;
	int ret;

	if (args->size == 0)
		return 0;

	if (!access_ok(u64_to_user_ptr(args->data_ptr), args->size))
		return -EFAULT;

	obj = i915_gem_object_lookup(file, args->handle);
	if (!obj)
		return -ENOENT;

	/* Bounds check destination. */
	if (range_overflows_t(u64, args->offset, args->size, obj->base.size)) {
		ret = -EINVAL;
		goto err;
	}

	/* Writes not allowed into this read-only object */
	if (i915_gem_object_is_readonly(obj)) {
		ret = -EINVAL;
		goto err;
	}

	trace_i915_gem_object_pwrite(obj, args->offset, args->size);

	ret = -ENODEV;
	if (obj->ops->pwrite)
		ret = obj->ops->pwrite(obj, args);
	if (ret != -ENODEV)
		goto err;

	ret = i915_gem_object_wait(obj,
				   I915_WAIT_INTERRUPTIBLE |
				   I915_WAIT_ALL,
				   MAX_SCHEDULE_TIMEOUT);
	if (ret)
		goto err;

	ret = i915_gem_object_pin_pages(obj);
	if (ret)
		goto err;

	ret = -EFAULT;
	/* We can only do the GTT pwrite on untiled buffers, as otherwise
	 * it would end up going through the fenced access, and we'll get
	 * different detiling behavior between reading and writing.
	 * pread/pwrite currently are reading and writing from the CPU
	 * perspective, requiring manual detiling by the client.
	 */
	if (!i915_gem_object_has_struct_page(obj) ||
	    cpu_write_needs_clflush(obj))
		/* Note that the gtt paths might fail with non-page-backed user
		 * pointers (e.g. gtt mappings when moving data between
		 * textures). Fallback to the shmem path in that case.
		 */
		ret = i915_gem_gtt_pwrite_fast(obj, args);

	if (ret == -EFAULT || ret == -ENOSPC) {
		if (obj->phys_handle)
			ret = i915_gem_phys_pwrite(obj, args, file);
		else
			ret = i915_gem_shmem_pwrite(obj, args);
	}

	i915_gem_object_unpin_pages(obj);
err:
	i915_gem_object_put(obj);
	return ret;
}

/**
 * Called when user space has done writes to this buffer
 * @dev: drm device
 * @data: ioctl data blob
 * @file: drm file
 */
int
i915_gem_sw_finish_ioctl(struct drm_device *dev, void *data,
			 struct drm_file *file)
{
	struct drm_i915_gem_sw_finish *args = data;
	struct drm_i915_gem_object *obj;

	obj = i915_gem_object_lookup(file, args->handle);
	if (!obj)
		return -ENOENT;

	/*
	 * Proxy objects are barred from CPU access, so there is no
	 * need to ban sw_finish as it is a nop.
	 */

	/* Pinned buffers may be scanout, so flush the cache */
	i915_gem_object_flush_if_display(obj);
	i915_gem_object_put(obj);

	return 0;
}

void i915_gem_runtime_suspend(struct drm_i915_private *dev_priv)
{
	struct drm_i915_gem_object *obj, *on;
	int i;

	/*
	 * Only called during RPM suspend. All users of the userfault_list
	 * must be holding an RPM wakeref to ensure that this can not
	 * run concurrently with themselves (and use the struct_mutex for
	 * protection between themselves).
	 */

	list_for_each_entry_safe(obj, on,
				 &dev_priv->mm.userfault_list, userfault_link)
		__i915_gem_object_release_mmap(obj);

	/* The fence will be lost when the device powers down. If any were
	 * in use by hardware (i.e. they are pinned), we should not be powering
	 * down! All other fences will be reacquired by the user upon waking.
	 */
	for (i = 0; i < dev_priv->num_fence_regs; i++) {
		struct drm_i915_fence_reg *reg = &dev_priv->fence_regs[i];

		/* Ideally we want to assert that the fence register is not
		 * live at this point (i.e. that no piece of code will be
		 * trying to write through fence + GTT, as that both violates
		 * our tracking of activity and associated locking/barriers,
		 * but also is illegal given that the hw is powered down).
		 *
		 * Previously we used reg->pin_count as a "liveness" indicator.
		 * That is not sufficient, and we need a more fine-grained
		 * tool if we want to have a sanity check here.
		 */

		if (!reg->vma)
			continue;

		GEM_BUG_ON(i915_vma_has_userfault(reg->vma));
		reg->dirty = true;
	}
}

bool i915_sg_trim(struct sg_table *orig_st)
{
	struct sg_table new_st;
	struct scatterlist *sg, *new_sg;
	unsigned int i;

	if (orig_st->nents == orig_st->orig_nents)
		return false;

	if (sg_alloc_table(&new_st, orig_st->nents, GFP_KERNEL | __GFP_NOWARN))
		return false;

	new_sg = new_st.sgl;
	for_each_sg(orig_st->sgl, sg, orig_st->nents, i) {
		sg_set_page(new_sg, sg_page(sg), sg->length, 0);
		sg_dma_address(new_sg) = sg_dma_address(sg);
		sg_dma_len(new_sg) = sg_dma_len(sg);

		new_sg = sg_next(new_sg);
	}
	GEM_BUG_ON(new_sg); /* Should walk exactly nents and hit the end */

	sg_free_table(orig_st);

	*orig_st = new_st;
	return true;
}

static unsigned long to_wait_timeout(s64 timeout_ns)
{
	if (timeout_ns < 0)
		return MAX_SCHEDULE_TIMEOUT;

	if (timeout_ns == 0)
		return 0;

	return nsecs_to_jiffies_timeout(timeout_ns);
}

/**
 * i915_gem_wait_ioctl - implements DRM_IOCTL_I915_GEM_WAIT
 * @dev: drm device pointer
 * @data: ioctl data blob
 * @file: drm file pointer
 *
 * Returns 0 if successful, else an error is returned with the remaining time in
 * the timeout parameter.
 *  -ETIME: object is still busy after timeout
 *  -ERESTARTSYS: signal interrupted the wait
 *  -ENONENT: object doesn't exist
 * Also possible, but rare:
 *  -EAGAIN: incomplete, restart syscall
 *  -ENOMEM: damn
 *  -ENODEV: Internal IRQ fail
 *  -E?: The add request failed
 *
 * The wait ioctl with a timeout of 0 reimplements the busy ioctl. With any
 * non-zero timeout parameter the wait ioctl will wait for the given number of
 * nanoseconds on an object becoming unbusy. Since the wait itself does so
 * without holding struct_mutex the object may become re-busied before this
 * function completes. A similar but shorter * race condition exists in the busy
 * ioctl
 */
int
i915_gem_wait_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
{
	struct drm_i915_gem_wait *args = data;
	struct drm_i915_gem_object *obj;
	ktime_t start;
	long ret;

	if (args->flags != 0)
		return -EINVAL;

	obj = i915_gem_object_lookup(file, args->bo_handle);
	if (!obj)
		return -ENOENT;

	start = ktime_get();

	ret = i915_gem_object_wait(obj,
				   I915_WAIT_INTERRUPTIBLE |
				   I915_WAIT_PRIORITY |
				   I915_WAIT_ALL,
				   to_wait_timeout(args->timeout_ns));

	if (args->timeout_ns > 0) {
		args->timeout_ns -= ktime_to_ns(ktime_sub(ktime_get(), start));
		if (args->timeout_ns < 0)
			args->timeout_ns = 0;

		/*
		 * Apparently ktime isn't accurate enough and occasionally has a
		 * bit of mismatch in the jiffies<->nsecs<->ktime loop. So patch
		 * things up to make the test happy. We allow up to 1 jiffy.
		 *
		 * This is a regression from the timespec->ktime conversion.
		 */
		if (ret == -ETIME && !nsecs_to_jiffies(args->timeout_ns))
			args->timeout_ns = 0;

		/* Asked to wait beyond the jiffie/scheduler precision? */
		if (ret == -ETIME && args->timeout_ns)
			ret = -EAGAIN;
	}

	i915_gem_object_put(obj);
	return ret;
}

static int wait_for_engines(struct drm_i915_private *i915)
{
	if (wait_for(intel_engines_are_idle(i915), I915_IDLE_ENGINES_TIMEOUT)) {
		dev_err(i915->drm.dev,
			"Failed to idle engines, declaring wedged!\n");
		GEM_TRACE_DUMP();
		i915_gem_set_wedged(i915);
		return -EIO;
	}

	return 0;
}

static long
wait_for_timelines(struct drm_i915_private *i915,
		   unsigned int flags, long timeout)
{
	struct i915_gt_timelines *gt = &i915->gt.timelines;
	struct i915_timeline *tl;

	mutex_lock(&gt->mutex);
	list_for_each_entry(tl, &gt->active_list, link) {
		struct i915_request *rq;

		rq = i915_active_request_get_unlocked(&tl->last_request);
		if (!rq)
			continue;

		mutex_unlock(&gt->mutex);

		/*
		 * "Race-to-idle".
		 *
		 * Switching to the kernel context is often used a synchronous
		 * step prior to idling, e.g. in suspend for flushing all
		 * current operations to memory before sleeping. These we
		 * want to complete as quickly as possible to avoid prolonged
		 * stalls, so allow the gpu to boost to maximum clocks.
		 */
		if (flags & I915_WAIT_FOR_IDLE_BOOST)
			gen6_rps_boost(rq);

		timeout = i915_request_wait(rq, flags, timeout);
		i915_request_put(rq);
		if (timeout < 0)
			return timeout;

		/* restart after reacquiring the lock */
		mutex_lock(&gt->mutex);
		tl = list_entry(&gt->active_list, typeof(*tl), link);
	}
	mutex_unlock(&gt->mutex);

	return timeout;
}

int i915_gem_wait_for_idle(struct drm_i915_private *i915,
			   unsigned int flags, long timeout)
{
	GEM_TRACE("flags=%x (%s), timeout=%ld%s, awake?=%s\n",
		  flags, flags & I915_WAIT_LOCKED ? "locked" : "unlocked",
		  timeout, timeout == MAX_SCHEDULE_TIMEOUT ? " (forever)" : "",
		  yesno(i915->gt.awake));

	/* If the device is asleep, we have no requests outstanding */
	if (!READ_ONCE(i915->gt.awake))
		return 0;

	timeout = wait_for_timelines(i915, flags, timeout);
	if (timeout < 0)
		return timeout;

	if (flags & I915_WAIT_LOCKED) {
		int err;

		lockdep_assert_held(&i915->drm.struct_mutex);

		err = wait_for_engines(i915);
		if (err)
			return err;

		i915_retire_requests(i915);
	}

	return 0;
}

/* Throttle our rendering by waiting until the ring has completed our requests
 * emitted over 20 msec ago.
 *
 * Note that if we were to use the current jiffies each time around the loop,
 * we wouldn't escape the function with any frames outstanding if the time to
 * render a frame was over 20ms.
 *
 * This should get us reasonable parallelism between CPU and GPU but also
 * relatively low latency when blocking on a particular request to finish.
 */
static int
i915_gem_ring_throttle(struct drm_device *dev, struct drm_file *file)
{
	struct drm_i915_private *dev_priv = to_i915(dev);
	struct drm_i915_file_private *file_priv = file->driver_priv;
	unsigned long recent_enough = jiffies - DRM_I915_THROTTLE_JIFFIES;
	struct i915_request *request, *target = NULL;
	long ret;

	/* ABI: return -EIO if already wedged */
	ret = i915_terminally_wedged(dev_priv);
	if (ret)
		return ret;

	spin_lock(&file_priv->mm.lock);
	list_for_each_entry(request, &file_priv->mm.request_list, client_link) {
		if (time_after_eq(request->emitted_jiffies, recent_enough))
			break;

		if (target) {
			list_del(&target->client_link);
			target->file_priv = NULL;
		}

		target = request;
	}
	if (target)
		i915_request_get(target);
	spin_unlock(&file_priv->mm.lock);

	if (target == NULL)
		return 0;

	ret = i915_request_wait(target,
				I915_WAIT_INTERRUPTIBLE,
				MAX_SCHEDULE_TIMEOUT);
	i915_request_put(target);

	return ret < 0 ? ret : 0;
}

struct i915_vma *
i915_gem_object_ggtt_pin(struct drm_i915_gem_object *obj,
			 const struct i915_ggtt_view *view,
			 u64 size,
			 u64 alignment,
			 u64 flags)
{
	struct drm_i915_private *dev_priv = to_i915(obj->base.dev);
	struct i915_address_space *vm = &dev_priv->ggtt.vm;
	struct i915_vma *vma;
	int ret;

	lockdep_assert_held(&obj->base.dev->struct_mutex);

	if (flags & PIN_MAPPABLE &&
	    (!view || view->type == I915_GGTT_VIEW_NORMAL)) {
		/* If the required space is larger than the available
		 * aperture, we will not able to find a slot for the
		 * object and unbinding the object now will be in
		 * vain. Worse, doing so may cause us to ping-pong
		 * the object in and out of the Global GTT and
		 * waste a lot of cycles under the mutex.
		 */
		if (obj->base.size > dev_priv->ggtt.mappable_end)
			return ERR_PTR(-E2BIG);

		/* If NONBLOCK is set the caller is optimistically
		 * trying to cache the full object within the mappable
		 * aperture, and *must* have a fallback in place for
		 * situations where we cannot bind the object. We
		 * can be a little more lax here and use the fallback
		 * more often to avoid costly migrations of ourselves
		 * and other objects within the aperture.
		 *
		 * Half-the-aperture is used as a simple heuristic.
		 * More interesting would to do search for a free
		 * block prior to making the commitment to unbind.
		 * That caters for the self-harm case, and with a
		 * little more heuristics (e.g. NOFAULT, NOEVICT)
		 * we could try to minimise harm to others.
		 */
		if (flags & PIN_NONBLOCK &&
		    obj->base.size > dev_priv->ggtt.mappable_end / 2)
			return ERR_PTR(-ENOSPC);
	}

	vma = i915_vma_instance(obj, vm, view);
	if (IS_ERR(vma))
		return vma;

	if (i915_vma_misplaced(vma, size, alignment, flags)) {
		if (flags & PIN_NONBLOCK) {
			if (i915_vma_is_pinned(vma) || i915_vma_is_active(vma))
				return ERR_PTR(-ENOSPC);

			if (flags & PIN_MAPPABLE &&
			    vma->fence_size > dev_priv->ggtt.mappable_end / 2)
				return ERR_PTR(-ENOSPC);
		}

		WARN(i915_vma_is_pinned(vma),
		     "bo is already pinned in ggtt with incorrect alignment:"
		     " offset=%08x, req.alignment=%llx,"
		     " req.map_and_fenceable=%d, vma->map_and_fenceable=%d\n",
		     i915_ggtt_offset(vma), alignment,
		     !!(flags & PIN_MAPPABLE),
		     i915_vma_is_map_and_fenceable(vma));
		ret = i915_vma_unbind(vma);
		if (ret)
			return ERR_PTR(ret);
	}

	ret = i915_vma_pin(vma, size, alignment, flags | PIN_GLOBAL);
	if (ret)
		return ERR_PTR(ret);

	return vma;
}

static __always_inline u32 __busy_read_flag(u8 id)
{
	if (id == (u8)I915_ENGINE_CLASS_INVALID)
		return 0xffff0000u;

	GEM_BUG_ON(id >= 16);
	return 0x10000u << id;
}

static __always_inline u32 __busy_write_id(u8 id)
{
	/*
	 * The uABI guarantees an active writer is also amongst the read
	 * engines. This would be true if we accessed the activity tracking
	 * under the lock, but as we perform the lookup of the object and
	 * its activity locklessly we can not guarantee that the last_write
	 * being active implies that we have set the same engine flag from
	 * last_read - hence we always set both read and write busy for
	 * last_write.
	 */
	if (id == (u8)I915_ENGINE_CLASS_INVALID)
		return 0xffffffffu;

	return (id + 1) | __busy_read_flag(id);
}

static __always_inline unsigned int
__busy_set_if_active(const struct dma_fence *fence, u32 (*flag)(u8 id))
{
	const struct i915_request *rq;

	/*
	 * We have to check the current hw status of the fence as the uABI
	 * guarantees forward progress. We could rely on the idle worker
	 * to eventually flush us, but to minimise latency just ask the
	 * hardware.
	 *
	 * Note we only report on the status of native fences.
	 */
	if (!dma_fence_is_i915(fence))
		return 0;

	/* opencode to_request() in order to avoid const warnings */
	rq = container_of(fence, const struct i915_request, fence);
	if (i915_request_completed(rq))
		return 0;

	/* Beware type-expansion follies! */
	BUILD_BUG_ON(!typecheck(u8, rq->engine->uabi_class));
	return flag(rq->engine->uabi_class);
}

static __always_inline unsigned int
busy_check_reader(const struct dma_fence *fence)
{
	return __busy_set_if_active(fence, __busy_read_flag);
}

static __always_inline unsigned int
busy_check_writer(const struct dma_fence *fence)
{
	if (!fence)
		return 0;

	return __busy_set_if_active(fence, __busy_write_id);
}

int
i915_gem_busy_ioctl(struct drm_device *dev, void *data,
		    struct drm_file *file)
{
	struct drm_i915_gem_busy *args = data;
	struct drm_i915_gem_object *obj;
	struct reservation_object_list *list;
	unsigned int seq;
	int err;

	err = -ENOENT;
	rcu_read_lock();
	obj = i915_gem_object_lookup_rcu(file, args->handle);
	if (!obj)
		goto out;

	/*
	 * A discrepancy here is that we do not report the status of
	 * non-i915 fences, i.e. even though we may report the object as idle,
	 * a call to set-domain may still stall waiting for foreign rendering.
	 * This also means that wait-ioctl may report an object as busy,
	 * where busy-ioctl considers it idle.
	 *
	 * We trade the ability to warn of foreign fences to report on which
	 * i915 engines are active for the object.
	 *
	 * Alternatively, we can trade that extra information on read/write
	 * activity with
	 *	args->busy =
	 *		!reservation_object_test_signaled_rcu(obj->resv, true);
	 * to report the overall busyness. This is what the wait-ioctl does.
	 *
	 */
retry:
	seq = raw_read_seqcount(&obj->resv->seq);

	/* Translate the exclusive fence to the READ *and* WRITE engine */
	args->busy = busy_check_writer(rcu_dereference(obj->resv->fence_excl));

	/* Translate shared fences to READ set of engines */
	list = rcu_dereference(obj->resv->fence);
	if (list) {
		unsigned int shared_count = list->shared_count, i;

		for (i = 0; i < shared_count; ++i) {
			struct dma_fence *fence =
				rcu_dereference(list->shared[i]);

			args->busy |= busy_check_reader(fence);
		}
	}

	if (args->busy && read_seqcount_retry(&obj->resv->seq, seq))
		goto retry;

	err = 0;
out:
	rcu_read_unlock();
	return err;
}

int
i915_gem_throttle_ioctl(struct drm_device *dev, void *data,
			struct drm_file *file_priv)
{
	return i915_gem_ring_throttle(dev, file_priv);
}

int
i915_gem_madvise_ioctl(struct drm_device *dev, void *data,
		       struct drm_file *file_priv)
{
	struct drm_i915_private *dev_priv = to_i915(dev);
	struct drm_i915_gem_madvise *args = data;
	struct drm_i915_gem_object *obj;
	int err;

	switch (args->madv) {
	case I915_MADV_DONTNEED:
	case I915_MADV_WILLNEED:
	    break;
	default:
	    return -EINVAL;
	}

	obj = i915_gem_object_lookup(file_priv, args->handle);
	if (!obj)
		return -ENOENT;

	err = mutex_lock_interruptible(&obj->mm.lock);
	if (err)
		goto out;

	if (i915_gem_object_has_pages(obj) &&
	    i915_gem_object_is_tiled(obj) &&
	    dev_priv->quirks & QUIRK_PIN_SWIZZLED_PAGES) {
		if (obj->mm.madv == I915_MADV_WILLNEED) {
			GEM_BUG_ON(!obj->mm.quirked);
			__i915_gem_object_unpin_pages(obj);
			obj->mm.quirked = false;
		}
		if (args->madv == I915_MADV_WILLNEED) {
			GEM_BUG_ON(obj->mm.quirked);
			__i915_gem_object_pin_pages(obj);
			obj->mm.quirked = true;
		}
	}

	if (obj->mm.madv != __I915_MADV_PURGED)
		obj->mm.madv = args->madv;

	/* if the object is no longer attached, discard its backing storage */
	if (obj->mm.madv == I915_MADV_DONTNEED &&
	    !i915_gem_object_has_pages(obj))
		i915_gem_object_truncate(obj);

	args->retained = obj->mm.madv != __I915_MADV_PURGED;
	mutex_unlock(&obj->mm.lock);

out:
	i915_gem_object_put(obj);
	return err;
}

void i915_gem_sanitize(struct drm_i915_private *i915)
{
	intel_wakeref_t wakeref;

	GEM_TRACE("\n");

	wakeref = intel_runtime_pm_get(i915);
	intel_uncore_forcewake_get(&i915->uncore, FORCEWAKE_ALL);

	/*
	 * As we have just resumed the machine and woken the device up from
	 * deep PCI sleep (presumably D3_cold), assume the HW has been reset
	 * back to defaults, recovering from whatever wedged state we left it
	 * in and so worth trying to use the device once more.
	 */
	if (i915_terminally_wedged(i915))
		i915_gem_unset_wedged(i915);

	/*
	 * If we inherit context state from the BIOS or earlier occupants
	 * of the GPU, the GPU may be in an inconsistent state when we
	 * try to take over. The only way to remove the earlier state
	 * is by resetting. However, resetting on earlier gen is tricky as
	 * it may impact the display and we are uncertain about the stability
	 * of the reset, so this could be applied to even earlier gen.
	 */
	intel_gt_sanitize(i915, false);

	intel_uncore_forcewake_put(&i915->uncore, FORCEWAKE_ALL);
	intel_runtime_pm_put(i915, wakeref);

	mutex_lock(&i915->drm.struct_mutex);
	i915_gem_contexts_lost(i915);
	mutex_unlock(&i915->drm.struct_mutex);
}

void i915_gem_init_swizzling(struct drm_i915_private *dev_priv)
{
	if (INTEL_GEN(dev_priv) < 5 ||
	    dev_priv->mm.bit_6_swizzle_x == I915_BIT_6_SWIZZLE_NONE)
		return;

	I915_WRITE(DISP_ARB_CTL, I915_READ(DISP_ARB_CTL) |
				 DISP_TILE_SURFACE_SWIZZLING);

	if (IS_GEN(dev_priv, 5))
		return;

	I915_WRITE(TILECTL, I915_READ(TILECTL) | TILECTL_SWZCTL);
	if (IS_GEN(dev_priv, 6))
		I915_WRITE(ARB_MODE, _MASKED_BIT_ENABLE(ARB_MODE_SWIZZLE_SNB));
	else if (IS_GEN(dev_priv, 7))
		I915_WRITE(ARB_MODE, _MASKED_BIT_ENABLE(ARB_MODE_SWIZZLE_IVB));
	else if (IS_GEN(dev_priv, 8))
		I915_WRITE(GAMTARBMODE, _MASKED_BIT_ENABLE(ARB_MODE_SWIZZLE_BDW));
	else
		BUG();
}

static void init_unused_ring(struct drm_i915_private *dev_priv, u32 base)
{
	I915_WRITE(RING_CTL(base), 0);
	I915_WRITE(RING_HEAD(base), 0);
	I915_WRITE(RING_TAIL(base), 0);
	I915_WRITE(RING_START(base), 0);
}

static void init_unused_rings(struct drm_i915_private *dev_priv)
{
	if (IS_I830(dev_priv)) {
		init_unused_ring(dev_priv, PRB1_BASE);
		init_unused_ring(dev_priv, SRB0_BASE);
		init_unused_ring(dev_priv, SRB1_BASE);
		init_unused_ring(dev_priv, SRB2_BASE);
		init_unused_ring(dev_priv, SRB3_BASE);
	} else if (IS_GEN(dev_priv, 2)) {
		init_unused_ring(dev_priv, SRB0_BASE);
		init_unused_ring(dev_priv, SRB1_BASE);
	} else if (IS_GEN(dev_priv, 3)) {
		init_unused_ring(dev_priv, PRB1_BASE);
		init_unused_ring(dev_priv, PRB2_BASE);
	}
}

int i915_gem_init_hw(struct drm_i915_private *dev_priv)
{
	int ret;

	dev_priv->gt.last_init_time = ktime_get();

	/* Double layer security blanket, see i915_gem_init() */
	intel_uncore_forcewake_get(&dev_priv->uncore, FORCEWAKE_ALL);

	if (HAS_EDRAM(dev_priv) && INTEL_GEN(dev_priv) < 9)
		I915_WRITE(HSW_IDICR, I915_READ(HSW_IDICR) | IDIHASHMSK(0xf));

	if (IS_HASWELL(dev_priv))
		I915_WRITE(MI_PREDICATE_RESULT_2, IS_HSW_GT3(dev_priv) ?
			   LOWER_SLICE_ENABLED : LOWER_SLICE_DISABLED);

	/* Apply the GT workarounds... */
	intel_gt_apply_workarounds(dev_priv);
	/* ...and determine whether they are sticking. */
	intel_gt_verify_workarounds(dev_priv, "init");

	i915_gem_init_swizzling(dev_priv);

	/*
	 * At least 830 can leave some of the unused rings
	 * "active" (ie. head != tail) after resume which
	 * will prevent c3 entry. Makes sure all unused rings
	 * are totally idle.
	 */
	init_unused_rings(dev_priv);

	BUG_ON(!dev_priv->kernel_context);
	ret = i915_terminally_wedged(dev_priv);
	if (ret)
		goto out;

	ret = i915_ppgtt_init_hw(dev_priv);
	if (ret) {
		DRM_ERROR("Enabling PPGTT failed (%d)\n", ret);
		goto out;
	}

	ret = intel_wopcm_init_hw(&dev_priv->wopcm);
	if (ret) {
		DRM_ERROR("Enabling WOPCM failed (%d)\n", ret);
		goto out;
	}

	/* We can't enable contexts until all firmware is loaded */
	ret = intel_uc_init_hw(dev_priv);
	if (ret) {
		DRM_ERROR("Enabling uc failed (%d)\n", ret);
		goto out;
	}

	intel_mocs_init_l3cc_table(dev_priv);

	/* Only when the HW is re-initialised, can we replay the requests */
	ret = intel_engines_resume(dev_priv);
	if (ret)
		goto cleanup_uc;

	intel_uncore_forcewake_put(&dev_priv->uncore, FORCEWAKE_ALL);

	intel_engines_set_scheduler_caps(dev_priv);
	return 0;

cleanup_uc:
	intel_uc_fini_hw(dev_priv);
out:
	intel_uncore_forcewake_put(&dev_priv->uncore, FORCEWAKE_ALL);

	return ret;
}

static int __intel_engines_record_defaults(struct drm_i915_private *i915)
{
	struct intel_engine_cs *engine;
	struct i915_gem_context *ctx;
	struct i915_gem_engines *e;
	enum intel_engine_id id;
	int err = 0;

	/*
	 * As we reset the gpu during very early sanitisation, the current
	 * register state on the GPU should reflect its defaults values.
	 * We load a context onto the hw (with restore-inhibit), then switch
	 * over to a second context to save that default register state. We
	 * can then prime every new context with that state so they all start
	 * from the same default HW values.
	 */

	ctx = i915_gem_context_create_kernel(i915, 0);
	if (IS_ERR(ctx))
		return PTR_ERR(ctx);

	e = i915_gem_context_lock_engines(ctx);

	for_each_engine(engine, i915, id) {
		struct intel_context *ce = e->engines[id];
		struct i915_request *rq;

		rq = intel_context_create_request(ce);
		if (IS_ERR(rq)) {
			err = PTR_ERR(rq);
			goto err_active;
		}

		err = 0;
		if (rq->engine->init_context)
			err = rq->engine->init_context(rq);

		i915_request_add(rq);
		if (err)
			goto err_active;
	}

	/* Flush the default context image to memory, and enable powersaving. */
	if (!i915_gem_load_power_context(i915)) {
		err = -EIO;
		goto err_active;
	}

	for_each_engine(engine, i915, id) {
		struct intel_context *ce = e->engines[id];
		struct i915_vma *state = ce->state;
		void *vaddr;

		if (!state)
			continue;

		GEM_BUG_ON(intel_context_is_pinned(ce));

		/*
		 * As we will hold a reference to the logical state, it will
		 * not be torn down with the context, and importantly the
		 * object will hold onto its vma (making it possible for a
		 * stray GTT write to corrupt our defaults). Unmap the vma
		 * from the GTT to prevent such accidents and reclaim the
		 * space.
		 */
		err = i915_vma_unbind(state);
		if (err)
			goto err_active;

		err = i915_gem_object_set_to_cpu_domain(state->obj, false);
		if (err)
			goto err_active;

		engine->default_state = i915_gem_object_get(state->obj);
		i915_gem_object_set_cache_coherency(engine->default_state,
						    I915_CACHE_LLC);

		/* Check we can acquire the image of the context state */
		vaddr = i915_gem_object_pin_map(engine->default_state,
						I915_MAP_FORCE_WB);
		if (IS_ERR(vaddr)) {
			err = PTR_ERR(vaddr);
			goto err_active;
		}

		i915_gem_object_unpin_map(engine->default_state);
	}

	if (IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)) {
		unsigned int found = intel_engines_has_context_isolation(i915);

		/*
		 * Make sure that classes with multiple engine instances all
		 * share the same basic configuration.
		 */
		for_each_engine(engine, i915, id) {
			unsigned int bit = BIT(engine->uabi_class);
			unsigned int expected = engine->default_state ? bit : 0;

			if ((found & bit) != expected) {
				DRM_ERROR("mismatching default context state for class %d on engine %s\n",
					  engine->uabi_class, engine->name);
			}
		}
	}

out_ctx:
	i915_gem_context_unlock_engines(ctx);
	i915_gem_context_set_closed(ctx);
	i915_gem_context_put(ctx);
	return err;

err_active:
	/*
	 * If we have to abandon now, we expect the engines to be idle
	 * and ready to be torn-down. The quickest way we can accomplish
	 * this is by declaring ourselves wedged.
	 */
	i915_gem_set_wedged(i915);
	goto out_ctx;
}

static int
i915_gem_init_scratch(struct drm_i915_private *i915, unsigned int size)
{
	struct drm_i915_gem_object *obj;
	struct i915_vma *vma;
	int ret;

	obj = i915_gem_object_create_stolen(i915, size);
	if (!obj)
		obj = i915_gem_object_create_internal(i915, size);
	if (IS_ERR(obj)) {
		DRM_ERROR("Failed to allocate scratch page\n");
		return PTR_ERR(obj);
	}

	vma = i915_vma_instance(obj, &i915->ggtt.vm, NULL);
	if (IS_ERR(vma)) {
		ret = PTR_ERR(vma);
		goto err_unref;
	}

	ret = i915_vma_pin(vma, 0, 0, PIN_GLOBAL | PIN_HIGH);
	if (ret)
		goto err_unref;

	i915->gt.scratch = vma;
	return 0;

err_unref:
	i915_gem_object_put(obj);
	return ret;
}

static void i915_gem_fini_scratch(struct drm_i915_private *i915)
{
	i915_vma_unpin_and_release(&i915->gt.scratch, 0);
}

static int intel_engines_verify_workarounds(struct drm_i915_private *i915)
{
	struct intel_engine_cs *engine;
	enum intel_engine_id id;
	int err = 0;

	if (!IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM))
		return 0;

	for_each_engine(engine, i915, id) {
		if (intel_engine_verify_workarounds(engine, "load"))
			err = -EIO;
	}

	return err;
}

int i915_gem_init(struct drm_i915_private *dev_priv)
{
	int ret;

	/* We need to fallback to 4K pages if host doesn't support huge gtt. */
	if (intel_vgpu_active(dev_priv) && !intel_vgpu_has_huge_gtt(dev_priv))
		mkwrite_device_info(dev_priv)->page_sizes =
			I915_GTT_PAGE_SIZE_4K;

	dev_priv->mm.unordered_timeline = dma_fence_context_alloc(1);

	i915_timelines_init(dev_priv);

	ret = i915_gem_init_userptr(dev_priv);
	if (ret)
		return ret;

	ret = intel_uc_init_misc(dev_priv);
	if (ret)
		return ret;

	ret = intel_wopcm_init(&dev_priv->wopcm);
	if (ret)
		goto err_uc_misc;

	/* This is just a security blanket to placate dragons.
	 * On some systems, we very sporadically observe that the first TLBs
	 * used by the CS may be stale, despite us poking the TLB reset. If
	 * we hold the forcewake during initialisation these problems
	 * just magically go away.
	 */
	mutex_lock(&dev_priv->drm.struct_mutex);
	intel_uncore_forcewake_get(&dev_priv->uncore, FORCEWAKE_ALL);

	ret = i915_gem_init_ggtt(dev_priv);
	if (ret) {
		GEM_BUG_ON(ret == -EIO);
		goto err_unlock;
	}

	ret = i915_gem_init_scratch(dev_priv,
				    IS_GEN(dev_priv, 2) ? SZ_256K : PAGE_SIZE);
	if (ret) {
		GEM_BUG_ON(ret == -EIO);
		goto err_ggtt;
	}

	ret = intel_engines_setup(dev_priv);
	if (ret) {
		GEM_BUG_ON(ret == -EIO);
		goto err_unlock;
	}

	ret = i915_gem_contexts_init(dev_priv);
	if (ret) {
		GEM_BUG_ON(ret == -EIO);
		goto err_scratch;
	}

	ret = intel_engines_init(dev_priv);
	if (ret) {
		GEM_BUG_ON(ret == -EIO);
		goto err_context;
	}

	intel_init_gt_powersave(dev_priv);

	ret = intel_uc_init(dev_priv);
	if (ret)
		goto err_pm;

	ret = i915_gem_init_hw(dev_priv);
	if (ret)
		goto err_uc_init;

	/*
	 * Despite its name intel_init_clock_gating applies both display
	 * clock gating workarounds; GT mmio workarounds and the occasional
	 * GT power context workaround. Worse, sometimes it includes a context
	 * register workaround which we need to apply before we record the
	 * default HW state for all contexts.
	 *
	 * FIXME: break up the workarounds and apply them at the right time!
	 */
	intel_init_clock_gating(dev_priv);

	ret = intel_engines_verify_workarounds(dev_priv);
	if (ret)
		goto err_init_hw;

	ret = __intel_engines_record_defaults(dev_priv);
	if (ret)
		goto err_init_hw;

	if (i915_inject_load_failure()) {
		ret = -ENODEV;
		goto err_init_hw;
	}

	if (i915_inject_load_failure()) {
		ret = -EIO;
		goto err_init_hw;
	}

	intel_uncore_forcewake_put(&dev_priv->uncore, FORCEWAKE_ALL);
	mutex_unlock(&dev_priv->drm.struct_mutex);

	return 0;

	/*
	 * Unwinding is complicated by that we want to handle -EIO to mean
	 * disable GPU submission but keep KMS alive. We want to mark the
	 * HW as irrevisibly wedged, but keep enough state around that the
	 * driver doesn't explode during runtime.
	 */
err_init_hw:
	mutex_unlock(&dev_priv->drm.struct_mutex);

	i915_gem_set_wedged(dev_priv);
	i915_gem_suspend(dev_priv);
	i915_gem_suspend_late(dev_priv);

	i915_gem_drain_workqueue(dev_priv);

	mutex_lock(&dev_priv->drm.struct_mutex);
	intel_uc_fini_hw(dev_priv);
err_uc_init:
	intel_uc_fini(dev_priv);
err_pm:
	if (ret != -EIO) {
		intel_cleanup_gt_powersave(dev_priv);
		intel_engines_cleanup(dev_priv);
	}
err_context:
	if (ret != -EIO)
		i915_gem_contexts_fini(dev_priv);
err_scratch:
	i915_gem_fini_scratch(dev_priv);
err_ggtt:
err_unlock:
	intel_uncore_forcewake_put(&dev_priv->uncore, FORCEWAKE_ALL);
	mutex_unlock(&dev_priv->drm.struct_mutex);

err_uc_misc:
	intel_uc_fini_misc(dev_priv);

	if (ret != -EIO) {
		i915_gem_cleanup_userptr(dev_priv);
		i915_timelines_fini(dev_priv);
	}

	if (ret == -EIO) {
		mutex_lock(&dev_priv->drm.struct_mutex);

		/*
		 * Allow engine initialisation to fail by marking the GPU as
		 * wedged. But we only want to do this where the GPU is angry,
		 * for all other failure, such as an allocation failure, bail.
		 */
		if (!i915_reset_failed(dev_priv)) {
			i915_load_error(dev_priv,
					"Failed to initialize GPU, declaring it wedged!\n");
			i915_gem_set_wedged(dev_priv);
		}

		/* Minimal basic recovery for KMS */
		ret = i915_ggtt_enable_hw(dev_priv);
		i915_gem_restore_gtt_mappings(dev_priv);
		i915_gem_restore_fences(dev_priv);
		intel_init_clock_gating(dev_priv);

		mutex_unlock(&dev_priv->drm.struct_mutex);
	}

	i915_gem_drain_freed_objects(dev_priv);
	return ret;
}

void i915_gem_fini(struct drm_i915_private *dev_priv)
{
	GEM_BUG_ON(dev_priv->gt.awake);

	intel_wakeref_auto_fini(&dev_priv->mm.userfault_wakeref);

	i915_gem_suspend_late(dev_priv);
	intel_disable_gt_powersave(dev_priv);

	/* Flush any outstanding unpin_work. */
	i915_gem_drain_workqueue(dev_priv);

	mutex_lock(&dev_priv->drm.struct_mutex);
	intel_uc_fini_hw(dev_priv);
	intel_uc_fini(dev_priv);
	intel_engines_cleanup(dev_priv);
	i915_gem_contexts_fini(dev_priv);
	i915_gem_fini_scratch(dev_priv);
	mutex_unlock(&dev_priv->drm.struct_mutex);

	intel_wa_list_free(&dev_priv->gt_wa_list);

	intel_cleanup_gt_powersave(dev_priv);

	intel_uc_fini_misc(dev_priv);
	i915_gem_cleanup_userptr(dev_priv);
	i915_timelines_fini(dev_priv);

	i915_gem_drain_freed_objects(dev_priv);

	WARN_ON(!list_empty(&dev_priv->contexts.list));
}

void i915_gem_init_mmio(struct drm_i915_private *i915)
{
	i915_gem_sanitize(i915);
}

void
i915_gem_load_init_fences(struct drm_i915_private *dev_priv)
{
	int i;

	if (INTEL_GEN(dev_priv) >= 7 && !IS_VALLEYVIEW(dev_priv) &&
	    !IS_CHERRYVIEW(dev_priv))
		dev_priv->num_fence_regs = 32;
	else if (INTEL_GEN(dev_priv) >= 4 ||
		 IS_I945G(dev_priv) || IS_I945GM(dev_priv) ||
		 IS_G33(dev_priv) || IS_PINEVIEW(dev_priv))
		dev_priv->num_fence_regs = 16;
	else
		dev_priv->num_fence_regs = 8;

	if (intel_vgpu_active(dev_priv))
		dev_priv->num_fence_regs =
				I915_READ(vgtif_reg(avail_rs.fence_num));

	/* Initialize fence registers to zero */
	for (i = 0; i < dev_priv->num_fence_regs; i++) {
		struct drm_i915_fence_reg *fence = &dev_priv->fence_regs[i];

		fence->i915 = dev_priv;
		fence->id = i;
		list_add_tail(&fence->link, &dev_priv->mm.fence_list);
	}
	i915_gem_restore_fences(dev_priv);

	i915_gem_detect_bit_6_swizzle(dev_priv);
}

static void i915_gem_init__mm(struct drm_i915_private *i915)
{
	spin_lock_init(&i915->mm.object_stat_lock);
	spin_lock_init(&i915->mm.obj_lock);
	spin_lock_init(&i915->mm.free_lock);

	init_llist_head(&i915->mm.free_list);

	INIT_LIST_HEAD(&i915->mm.unbound_list);
	INIT_LIST_HEAD(&i915->mm.bound_list);
	INIT_LIST_HEAD(&i915->mm.fence_list);

	INIT_LIST_HEAD(&i915->mm.userfault_list);
	intel_wakeref_auto_init(&i915->mm.userfault_wakeref, i915);

	i915_gem_init__objects(i915);
}

int i915_gem_init_early(struct drm_i915_private *dev_priv)
{
	int err;

	intel_gt_pm_init(dev_priv);

	INIT_LIST_HEAD(&dev_priv->gt.active_rings);
	INIT_LIST_HEAD(&dev_priv->gt.closed_vma);

	i915_gem_init__mm(dev_priv);
	i915_gem_init__pm(dev_priv);

	init_waitqueue_head(&dev_priv->gpu_error.wait_queue);
	init_waitqueue_head(&dev_priv->gpu_error.reset_queue);
	mutex_init(&dev_priv->gpu_error.wedge_mutex);
	init_srcu_struct(&dev_priv->gpu_error.reset_backoff_srcu);

	atomic_set(&dev_priv->mm.bsd_engine_dispatch_index, 0);

	spin_lock_init(&dev_priv->fb_tracking.lock);

	err = i915_gemfs_init(dev_priv);
	if (err)
		DRM_NOTE("Unable to create a private tmpfs mount, hugepage support will be disabled(%d).\n", err);

	return 0;
}

void i915_gem_cleanup_early(struct drm_i915_private *dev_priv)
{
	i915_gem_drain_freed_objects(dev_priv);
	GEM_BUG_ON(!llist_empty(&dev_priv->mm.free_list));
	GEM_BUG_ON(atomic_read(&dev_priv->mm.free_count));
	WARN_ON(dev_priv->mm.object_count);

	cleanup_srcu_struct(&dev_priv->gpu_error.reset_backoff_srcu);

	i915_gemfs_fini(dev_priv);
}

int i915_gem_freeze(struct drm_i915_private *dev_priv)
{
	/* Discard all purgeable objects, let userspace recover those as
	 * required after resuming.
	 */
	i915_gem_shrink_all(dev_priv);

	return 0;
}

int i915_gem_freeze_late(struct drm_i915_private *i915)
{
	struct drm_i915_gem_object *obj;
	struct list_head *phases[] = {
		&i915->mm.unbound_list,
		&i915->mm.bound_list,
		NULL
	}, **phase;

	/*
	 * Called just before we write the hibernation image.
	 *
	 * We need to update the domain tracking to reflect that the CPU
	 * will be accessing all the pages to create and restore from the
	 * hibernation, and so upon restoration those pages will be in the
	 * CPU domain.
	 *
	 * To make sure the hibernation image contains the latest state,
	 * we update that state just before writing out the image.
	 *
	 * To try and reduce the hibernation image, we manually shrink
	 * the objects as well, see i915_gem_freeze()
	 */

	i915_gem_shrink(i915, -1UL, NULL, I915_SHRINK_UNBOUND);
	i915_gem_drain_freed_objects(i915);

	mutex_lock(&i915->drm.struct_mutex);
	for (phase = phases; *phase; phase++) {
		list_for_each_entry(obj, *phase, mm.link)
			WARN_ON(i915_gem_object_set_to_cpu_domain(obj, true));
	}
	mutex_unlock(&i915->drm.struct_mutex);

	return 0;
}

void i915_gem_release(struct drm_device *dev, struct drm_file *file)
{
	struct drm_i915_file_private *file_priv = file->driver_priv;
	struct i915_request *request;

	/* Clean up our request list when the client is going away, so that
	 * later retire_requests won't dereference our soon-to-be-gone
	 * file_priv.
	 */
	spin_lock(&file_priv->mm.lock);
	list_for_each_entry(request, &file_priv->mm.request_list, client_link)
		request->file_priv = NULL;
	spin_unlock(&file_priv->mm.lock);
}

int i915_gem_open(struct drm_i915_private *i915, struct drm_file *file)
{
	struct drm_i915_file_private *file_priv;
	int ret;

	DRM_DEBUG("\n");

	file_priv = kzalloc(sizeof(*file_priv), GFP_KERNEL);
	if (!file_priv)
		return -ENOMEM;

	file->driver_priv = file_priv;
	file_priv->dev_priv = i915;
	file_priv->file = file;

	spin_lock_init(&file_priv->mm.lock);
	INIT_LIST_HEAD(&file_priv->mm.request_list);

	file_priv->bsd_engine = -1;
	file_priv->hang_timestamp = jiffies;

	ret = i915_gem_context_open(i915, file);
	if (ret)
		kfree(file_priv);

	return ret;
}

/**
 * i915_gem_track_fb - update frontbuffer tracking
 * @old: current GEM buffer for the frontbuffer slots
 * @new: new GEM buffer for the frontbuffer slots
 * @frontbuffer_bits: bitmask of frontbuffer slots
 *
 * This updates the frontbuffer tracking bits @frontbuffer_bits by clearing them
 * from @old and setting them in @new. Both @old and @new can be NULL.
 */
void i915_gem_track_fb(struct drm_i915_gem_object *old,
		       struct drm_i915_gem_object *new,
		       unsigned frontbuffer_bits)
{
	/* Control of individual bits within the mask are guarded by
	 * the owning plane->mutex, i.e. we can never see concurrent
	 * manipulation of individual bits. But since the bitfield as a whole
	 * is updated using RMW, we need to use atomics in order to update
	 * the bits.
	 */
	BUILD_BUG_ON(INTEL_FRONTBUFFER_BITS_PER_PIPE * I915_MAX_PIPES >
		     BITS_PER_TYPE(atomic_t));

	if (old) {
		WARN_ON(!(atomic_read(&old->frontbuffer_bits) & frontbuffer_bits));
		atomic_andnot(frontbuffer_bits, &old->frontbuffer_bits);
	}

	if (new) {
		WARN_ON(atomic_read(&new->frontbuffer_bits) & frontbuffer_bits);
		atomic_or(frontbuffer_bits, &new->frontbuffer_bits);
	}
}

#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
#include "selftests/scatterlist.c"
#include "selftests/mock_gem_device.c"
#include "selftests/i915_gem.c"
#endif