Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1105 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
new file mode 100644
index 0000000000..310654542b
--- /dev/null
+++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
@@ -0,0 +1,1105 @@
+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright © 2014-2016 Intel Corporation
+ */
+
+#include <linux/anon_inodes.h>
+#include <linux/mman.h>
+#include <linux/pfn_t.h>
+#include <linux/sizes.h>
+
+#include <drm/drm_cache.h>
+
+#include "gt/intel_gt.h"
+#include "gt/intel_gt_requests.h"
+
+#include "i915_drv.h"
+#include "i915_gem_evict.h"
+#include "i915_gem_gtt.h"
+#include "i915_gem_ioctls.h"
+#include "i915_gem_object.h"
+#include "i915_gem_mman.h"
+#include "i915_mm.h"
+#include "i915_trace.h"
+#include "i915_user_extensions.h"
+#include "i915_gem_ttm.h"
+#include "i915_vma.h"
+
+static inline bool
+__vma_matches(struct vm_area_struct *vma, struct file *filp,
+	      unsigned long addr, unsigned long size)
+{
+	if (vma->vm_file != filp)
+		return false;
+
+	return vma->vm_start == addr &&
+	       (vma->vm_end - vma->vm_start) == PAGE_ALIGN(size);
+}
+
+/**
+ * i915_gem_mmap_ioctl - Maps the contents of an object, returning the address
+ *			 it is mapped to.
+ * @dev: drm device
+ * @data: ioctl data blob
+ * @file: drm file
+ *
+ * While the mapping holds a reference on the contents of the object, it doesn't
+ * imply a ref on the object itself.
+ *
+ * IMPORTANT:
+ *
+ * DRM driver writers who look a this function as an example for how to do GEM
+ * mmap support, please don't implement mmap support like here. The modern way
+ * to implement DRM mmap support is with an mmap offset ioctl (like
+ * i915_gem_mmap_gtt) and then using the mmap syscall on the DRM fd directly.
+ * That way debug tooling like valgrind will understand what's going on, hiding
+ * the mmap call in a driver private ioctl will break that. The i915 driver only
+ * does cpu mmaps this way because we didn't know better.
+ */
+int
+i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
+		    struct drm_file *file)
+{
+	struct drm_i915_private *i915 = to_i915(dev);
+	struct drm_i915_gem_mmap *args = data;
+	struct drm_i915_gem_object *obj;
+	unsigned long addr;
+
+	/*
+	 * mmap ioctl is disallowed for all discrete platforms,
+	 * and for all platforms with GRAPHICS_VER > 12.
+	 */
+	if (IS_DGFX(i915) || GRAPHICS_VER_FULL(i915) > IP_VER(12, 0))
+		return -EOPNOTSUPP;
+
+	if (args->flags & ~(I915_MMAP_WC))
+		return -EINVAL;
+
+	if (args->flags & I915_MMAP_WC && !pat_enabled())
+		return -ENODEV;
+
+	obj = i915_gem_object_lookup(file, args->handle);
+	if (!obj)
+		return -ENOENT;
+
+	/* prime objects have no backing filp to GEM mmap
+	 * pages from.
+	 */
+	if (!obj->base.filp) {
+		addr = -ENXIO;
+		goto err;
+	}
+
+	if (range_overflows(args->offset, args->size, (u64)obj->base.size)) {
+		addr = -EINVAL;
+		goto err;
+	}
+
+	addr = vm_mmap(obj->base.filp, 0, args->size,
+		       PROT_READ | PROT_WRITE, MAP_SHARED,
+		       args->offset);
+	if (IS_ERR_VALUE(addr))
+		goto err;
+
+	if (args->flags & I915_MMAP_WC) {
+		struct mm_struct *mm = current->mm;
+		struct vm_area_struct *vma;
+
+		if (mmap_write_lock_killable(mm)) {
+			addr = -EINTR;
+			goto err;
+		}
+		vma = find_vma(mm, addr);
+		if (vma && __vma_matches(vma, obj->base.filp, addr, args->size))
+			vma->vm_page_prot =
+				pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
+		else
+			addr = -ENOMEM;
+		mmap_write_unlock(mm);
+		if (IS_ERR_VALUE(addr))
+			goto err;
+	}
+	i915_gem_object_put(obj);
+
+	args->addr_ptr = (u64)addr;
+	return 0;
+
+err:
+	i915_gem_object_put(obj);
+	return addr;
+}
+
+static unsigned int tile_row_pages(const struct drm_i915_gem_object *obj)
+{
+	return i915_gem_object_get_tile_row_size(obj) >> PAGE_SHIFT;
+}
+
+/**
+ * i915_gem_mmap_gtt_version - report the current feature set for GTT mmaps
+ *
+ * A history of the GTT mmap interface:
+ *
+ * 0 - Everything had to fit into the GTT. Both parties of a memcpy had to
+ *     aligned and suitable for fencing, and still fit into the available
+ *     mappable space left by the pinned display objects. A classic problem
+ *     we called the page-fault-of-doom where we would ping-pong between
+ *     two objects that could not fit inside the GTT and so the memcpy
+ *     would page one object in at the expense of the other between every
+ *     single byte.
+ *
+ * 1 - Objects can be any size, and have any compatible fencing (X Y, or none
+ *     as set via i915_gem_set_tiling() [DRM_I915_GEM_SET_TILING]). If the
+ *     object is too large for the available space (or simply too large
+ *     for the mappable aperture!), a view is created instead and faulted
+ *     into userspace. (This view is aligned and sized appropriately for
+ *     fenced access.)
+ *
+ * 2 - Recognise WC as a separate cache domain so that we can flush the
+ *     delayed writes via GTT before performing direct access via WC.
+ *
+ * 3 - Remove implicit set-domain(GTT) and synchronisation on initial
+ *     pagefault; swapin remains transparent.
+ *
+ * 4 - Support multiple fault handlers per object depending on object's
+ *     backing storage (a.k.a. MMAP_OFFSET).
+ *
+ * Restrictions:
+ *
+ *  * snoopable objects cannot be accessed via the GTT. It can cause machine
+ *    hangs on some architectures, corruption on others. An attempt to service
+ *    a GTT page fault from a snoopable object will generate a SIGBUS.
+ *
+ *  * the object must be able to fit into RAM (physical memory, though no
+ *    limited to the mappable aperture).
+ *
+ *
+ * Caveats:
+ *
+ *  * a new GTT page fault will synchronize rendering from the GPU and flush
+ *    all data to system memory. Subsequent access will not be synchronized.
+ *
+ *  * all mappings are revoked on runtime device suspend.
+ *
+ *  * there are only 8, 16 or 32 fence registers to share between all users
+ *    (older machines require fence register for display and blitter access
+ *    as well). Contention of the fence registers will cause the previous users
+ *    to be unmapped and any new access will generate new page faults.
+ *
+ *  * running out of memory while servicing a fault may generate a SIGBUS,
+ *    rather than the expected SIGSEGV.
+ */
+int i915_gem_mmap_gtt_version(void)
+{
+	return 4;
+}
+
+static inline struct i915_gtt_view
+compute_partial_view(const struct drm_i915_gem_object *obj,
+		     pgoff_t page_offset,
+		     unsigned int chunk)
+{
+	struct i915_gtt_view view;
+
+	if (i915_gem_object_is_tiled(obj))
+		chunk = roundup(chunk, tile_row_pages(obj) ?: 1);
+
+	view.type = I915_GTT_VIEW_PARTIAL;
+	view.partial.offset = rounddown(page_offset, chunk);
+	view.partial.size =
+		min_t(unsigned int, chunk,
+		      (obj->base.size >> PAGE_SHIFT) - view.partial.offset);
+
+	/* If the partial covers the entire object, just create a normal VMA. */
+	if (chunk >= obj->base.size >> PAGE_SHIFT)
+		view.type = I915_GTT_VIEW_NORMAL;
+
+	return view;
+}
+
+static vm_fault_t i915_error_to_vmf_fault(int err)
+{
+	switch (err) {
+	default:
+		WARN_ONCE(err, "unhandled error in %s: %i\n", __func__, err);
+		fallthrough;
+	case -EIO: /* shmemfs failure from swap device */
+	case -EFAULT: /* purged object */
+	case -ENODEV: /* bad object, how did you get here! */
+	case -ENXIO: /* unable to access backing store (on device) */
+		return VM_FAULT_SIGBUS;
+
+	case -ENOMEM: /* our allocation failure */
+		return VM_FAULT_OOM;
+
+	case 0:
+	case -EAGAIN:
+	case -ENOSPC: /* transient failure to evict? */
+	case -ENOBUFS: /* temporarily out of fences? */
+	case -ERESTARTSYS:
+	case -EINTR:
+	case -EBUSY:
+		/*
+		 * EBUSY is ok: this just means that another thread
+		 * already did the job.
+		 */
+		return VM_FAULT_NOPAGE;
+	}
+}
+
+static vm_fault_t vm_fault_cpu(struct vm_fault *vmf)
+{
+	struct vm_area_struct *area = vmf->vma;
+	struct i915_mmap_offset *mmo = area->vm_private_data;
+	struct drm_i915_gem_object *obj = mmo->obj;
+	resource_size_t iomap;
+	int err;
+
+	/* Sanity check that we allow writing into this object */
+	if (unlikely(i915_gem_object_is_readonly(obj) &&
+		     area->vm_flags & VM_WRITE))
+		return VM_FAULT_SIGBUS;
+
+	if (i915_gem_object_lock_interruptible(obj, NULL))
+		return VM_FAULT_NOPAGE;
+
+	err = i915_gem_object_pin_pages(obj);
+	if (err)
+		goto out;
+
+	iomap = -1;
+	if (!i915_gem_object_has_struct_page(obj)) {
+		iomap = obj->mm.region->iomap.base;
+		iomap -= obj->mm.region->region.start;
+	}
+
+	/* PTEs are revoked in obj->ops->put_pages() */
+	err = remap_io_sg(area,
+			  area->vm_start, area->vm_end - area->vm_start,
+			  obj->mm.pages->sgl, iomap);
+
+	if (area->vm_flags & VM_WRITE) {
+		GEM_BUG_ON(!i915_gem_object_has_pinned_pages(obj));
+		obj->mm.dirty = true;
+	}
+
+	i915_gem_object_unpin_pages(obj);
+
+out:
+	i915_gem_object_unlock(obj);
+	return i915_error_to_vmf_fault(err);
+}
+
+static vm_fault_t vm_fault_gtt(struct vm_fault *vmf)
+{
+#define MIN_CHUNK_PAGES (SZ_1M >> PAGE_SHIFT)
+	struct vm_area_struct *area = vmf->vma;
+	struct i915_mmap_offset *mmo = area->vm_private_data;
+	struct drm_i915_gem_object *obj = mmo->obj;
+	struct drm_device *dev = obj->base.dev;
+	struct drm_i915_private *i915 = to_i915(dev);
+	struct intel_runtime_pm *rpm = &i915->runtime_pm;
+	struct i915_ggtt *ggtt = to_gt(i915)->ggtt;
+	bool write = area->vm_flags & VM_WRITE;
+	struct i915_gem_ww_ctx ww;
+	intel_wakeref_t wakeref;
+	struct i915_vma *vma;
+	pgoff_t page_offset;
+	int srcu;
+	int ret;
+
+	/* We don't use vmf->pgoff since that has the fake offset */
+	page_offset = (vmf->address - area->vm_start) >> PAGE_SHIFT;
+
+	trace_i915_gem_object_fault(obj, page_offset, true, write);
+
+	wakeref = intel_runtime_pm_get(rpm);
+
+	i915_gem_ww_ctx_init(&ww, true);
+retry:
+	ret = i915_gem_object_lock(obj, &ww);
+	if (ret)
+		goto err_rpm;
+
+	/* Sanity check that we allow writing into this object */
+	if (i915_gem_object_is_readonly(obj) && write) {
+		ret = -EFAULT;
+		goto err_rpm;
+	}
+
+	ret = i915_gem_object_pin_pages(obj);
+	if (ret)
+		goto err_rpm;
+
+	ret = intel_gt_reset_lock_interruptible(ggtt->vm.gt, &srcu);
+	if (ret)
+		goto err_pages;
+
+	/* Now pin it into the GTT as needed */
+	vma = i915_gem_object_ggtt_pin_ww(obj, &ww, NULL, 0, 0,
+					  PIN_MAPPABLE |
+					  PIN_NONBLOCK /* NOWARN */ |
+					  PIN_NOEVICT);
+	if (IS_ERR(vma) && vma != ERR_PTR(-EDEADLK)) {
+		/* Use a partial view if it is bigger than available space */
+		struct i915_gtt_view view =
+			compute_partial_view(obj, page_offset, MIN_CHUNK_PAGES);
+		unsigned int flags;
+
+		flags = PIN_MAPPABLE | PIN_NOSEARCH;
+		if (view.type == I915_GTT_VIEW_NORMAL)
+			flags |= PIN_NONBLOCK; /* avoid warnings for pinned */
+
+		/*
+		 * Userspace is now writing through an untracked VMA, abandon
+		 * all hope that the hardware is able to track future writes.
+		 */
+
+		vma = i915_gem_object_ggtt_pin_ww(obj, &ww, &view, 0, 0, flags);
+		if (IS_ERR(vma) && vma != ERR_PTR(-EDEADLK)) {
+			flags = PIN_MAPPABLE;
+			view.type = I915_GTT_VIEW_PARTIAL;
+			vma = i915_gem_object_ggtt_pin_ww(obj, &ww, &view, 0, 0, flags);
+		}
+
+		/*
+		 * The entire mappable GGTT is pinned? Unexpected!
+		 * Try to evict the object we locked too, as normally we skip it
+		 * due to lack of short term pinning inside execbuf.
+		 */
+		if (vma == ERR_PTR(-ENOSPC)) {
+			ret = mutex_lock_interruptible(&ggtt->vm.mutex);
+			if (!ret) {
+				ret = i915_gem_evict_vm(&ggtt->vm, &ww, NULL);
+				mutex_unlock(&ggtt->vm.mutex);
+			}
+			if (ret)
+				goto err_reset;
+			vma = i915_gem_object_ggtt_pin_ww(obj, &ww, &view, 0, 0, flags);
+		}
+	}
+	if (IS_ERR(vma)) {
+		ret = PTR_ERR(vma);
+		goto err_reset;
+	}
+
+	/* Access to snoopable pages through the GTT is incoherent. */
+	/*
+	 * For objects created by userspace through GEM_CREATE with pat_index
+	 * set by set_pat extension, coherency is managed by userspace, make
+	 * sure we don't fail handling the vm fault by calling
+	 * i915_gem_object_has_cache_level() which always return true for such
+	 * objects. Otherwise this helper function would fall back to checking
+	 * whether the object is un-cached.
+	 */
+	if (!(i915_gem_object_has_cache_level(obj, I915_CACHE_NONE) ||
+	      HAS_LLC(i915))) {
+		ret = -EFAULT;
+		goto err_unpin;
+	}
+
+	ret = i915_vma_pin_fence(vma);
+	if (ret)
+		goto err_unpin;
+
+	/* Finally, remap it using the new GTT offset */
+	ret = remap_io_mapping(area,
+			       area->vm_start + (vma->gtt_view.partial.offset << PAGE_SHIFT),
+			       (ggtt->gmadr.start + i915_ggtt_offset(vma)) >> PAGE_SHIFT,
+			       min_t(u64, vma->size, area->vm_end - area->vm_start),
+			       &ggtt->iomap);
+	if (ret)
+		goto err_fence;
+
+	assert_rpm_wakelock_held(rpm);
+
+	/* Mark as being mmapped into userspace for later revocation */
+	mutex_lock(&to_gt(i915)->ggtt->vm.mutex);
+	if (!i915_vma_set_userfault(vma) && !obj->userfault_count++)
+		list_add(&obj->userfault_link, &to_gt(i915)->ggtt->userfault_list);
+	mutex_unlock(&to_gt(i915)->ggtt->vm.mutex);
+
+	/* Track the mmo associated with the fenced vma */
+	vma->mmo = mmo;
+
+	if (CONFIG_DRM_I915_USERFAULT_AUTOSUSPEND)
+		intel_wakeref_auto(&i915->runtime_pm.userfault_wakeref,
+				   msecs_to_jiffies_timeout(CONFIG_DRM_I915_USERFAULT_AUTOSUSPEND));
+
+	if (write) {
+		GEM_BUG_ON(!i915_gem_object_has_pinned_pages(obj));
+		i915_vma_set_ggtt_write(vma);
+		obj->mm.dirty = true;
+	}
+
+err_fence:
+	i915_vma_unpin_fence(vma);
+err_unpin:
+	__i915_vma_unpin(vma);
+err_reset:
+	intel_gt_reset_unlock(ggtt->vm.gt, srcu);
+err_pages:
+	i915_gem_object_unpin_pages(obj);
+err_rpm:
+	if (ret == -EDEADLK) {
+		ret = i915_gem_ww_ctx_backoff(&ww);
+		if (!ret)
+			goto retry;
+	}
+	i915_gem_ww_ctx_fini(&ww);
+	intel_runtime_pm_put(rpm, wakeref);
+	return i915_error_to_vmf_fault(ret);
+}
+
+static int
+vm_access(struct vm_area_struct *area, unsigned long addr,
+	  void *buf, int len, int write)
+{
+	struct i915_mmap_offset *mmo = area->vm_private_data;
+	struct drm_i915_gem_object *obj = mmo->obj;
+	struct i915_gem_ww_ctx ww;
+	void *vaddr;
+	int err = 0;
+
+	if (i915_gem_object_is_readonly(obj) && write)
+		return -EACCES;
+
+	addr -= area->vm_start;
+	if (range_overflows_t(u64, addr, len, obj->base.size))
+		return -EINVAL;
+
+	i915_gem_ww_ctx_init(&ww, true);
+retry:
+	err = i915_gem_object_lock(obj, &ww);
+	if (err)
+		goto out;
+
+	/* As this is primarily for debugging, let's focus on simplicity */
+	vaddr = i915_gem_object_pin_map(obj, I915_MAP_FORCE_WC);
+	if (IS_ERR(vaddr)) {
+		err = PTR_ERR(vaddr);
+		goto out;
+	}
+
+	if (write) {
+		memcpy(vaddr + addr, buf, len);
+		__i915_gem_object_flush_map(obj, addr, len);
+	} else {
+		memcpy(buf, vaddr + addr, len);
+	}
+
+	i915_gem_object_unpin_map(obj);
+out:
+	if (err == -EDEADLK) {
+		err = i915_gem_ww_ctx_backoff(&ww);
+		if (!err)
+			goto retry;
+	}
+	i915_gem_ww_ctx_fini(&ww);
+
+	if (err)
+		return err;
+
+	return len;
+}
+
+void __i915_gem_object_release_mmap_gtt(struct drm_i915_gem_object *obj)
+{
+	struct i915_vma *vma;
+
+	GEM_BUG_ON(!obj->userfault_count);
+
+	for_each_ggtt_vma(vma, obj)
+		i915_vma_revoke_mmap(vma);
+
+	GEM_BUG_ON(obj->userfault_count);
+}
+
+/*
+ * It is vital that we remove the page mapping if we have mapped a tiled
+ * object through the GTT and then lose the fence register due to
+ * resource pressure. Similarly if the object has been moved out of the
+ * aperture, than pages mapped into userspace must be revoked. Removing the
+ * mapping will then trigger a page fault on the next user access, allowing
+ * fixup by vm_fault_gtt().
+ */
+void i915_gem_object_release_mmap_gtt(struct drm_i915_gem_object *obj)
+{
+	struct drm_i915_private *i915 = to_i915(obj->base.dev);
+	intel_wakeref_t wakeref;
+
+	/*
+	 * Serialisation between user GTT access and our code depends upon
+	 * revoking the CPU's PTE whilst the mutex is held. The next user
+	 * pagefault then has to wait until we release the mutex.
+	 *
+	 * Note that RPM complicates somewhat by adding an additional
+	 * requirement that operations to the GGTT be made holding the RPM
+	 * wakeref.
+	 */
+	wakeref = intel_runtime_pm_get(&i915->runtime_pm);
+	mutex_lock(&to_gt(i915)->ggtt->vm.mutex);
+
+	if (!obj->userfault_count)
+		goto out;
+
+	__i915_gem_object_release_mmap_gtt(obj);
+
+	/*
+	 * Ensure that the CPU's PTE are revoked and there are not outstanding
+	 * memory transactions from userspace before we return. The TLB
+	 * flushing implied above by changing the PTE above *should* be
+	 * sufficient, an extra barrier here just provides us with a bit
+	 * of paranoid documentation about our requirement to serialise
+	 * memory writes before touching registers / GSM.
+	 */
+	wmb();
+
+out:
+	mutex_unlock(&to_gt(i915)->ggtt->vm.mutex);
+	intel_runtime_pm_put(&i915->runtime_pm, wakeref);
+}
+
+void i915_gem_object_runtime_pm_release_mmap_offset(struct drm_i915_gem_object *obj)
+{
+	struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
+	struct ttm_device *bdev = bo->bdev;
+
+	drm_vma_node_unmap(&bo->base.vma_node, bdev->dev_mapping);
+
+	/*
+	 * We have exclusive access here via runtime suspend. All other callers
+	 * must first grab the rpm wakeref.
+	 */
+	GEM_BUG_ON(!obj->userfault_count);
+	list_del(&obj->userfault_link);
+	obj->userfault_count = 0;
+}
+
+void i915_gem_object_release_mmap_offset(struct drm_i915_gem_object *obj)
+{
+	struct i915_mmap_offset *mmo, *mn;
+
+	if (obj->ops->unmap_virtual)
+		obj->ops->unmap_virtual(obj);
+
+	spin_lock(&obj->mmo.lock);
+	rbtree_postorder_for_each_entry_safe(mmo, mn,
+					     &obj->mmo.offsets, offset) {
+		/*
+		 * vma_node_unmap for GTT mmaps handled already in
+		 * __i915_gem_object_release_mmap_gtt
+		 */
+		if (mmo->mmap_type == I915_MMAP_TYPE_GTT)
+			continue;
+
+		spin_unlock(&obj->mmo.lock);
+		drm_vma_node_unmap(&mmo->vma_node,
+				   obj->base.dev->anon_inode->i_mapping);
+		spin_lock(&obj->mmo.lock);
+	}
+	spin_unlock(&obj->mmo.lock);
+}
+
+static struct i915_mmap_offset *
+lookup_mmo(struct drm_i915_gem_object *obj,
+	   enum i915_mmap_type mmap_type)
+{
+	struct rb_node *rb;
+
+	spin_lock(&obj->mmo.lock);
+	rb = obj->mmo.offsets.rb_node;
+	while (rb) {
+		struct i915_mmap_offset *mmo =
+			rb_entry(rb, typeof(*mmo), offset);
+
+		if (mmo->mmap_type == mmap_type) {
+			spin_unlock(&obj->mmo.lock);
+			return mmo;
+		}
+
+		if (mmo->mmap_type < mmap_type)
+			rb = rb->rb_right;
+		else
+			rb = rb->rb_left;
+	}
+	spin_unlock(&obj->mmo.lock);
+
+	return NULL;
+}
+
+static struct i915_mmap_offset *
+insert_mmo(struct drm_i915_gem_object *obj, struct i915_mmap_offset *mmo)
+{
+	struct rb_node *rb, **p;
+
+	spin_lock(&obj->mmo.lock);
+	rb = NULL;
+	p = &obj->mmo.offsets.rb_node;
+	while (*p) {
+		struct i915_mmap_offset *pos;
+
+		rb = *p;
+		pos = rb_entry(rb, typeof(*pos), offset);
+
+		if (pos->mmap_type == mmo->mmap_type) {
+			spin_unlock(&obj->mmo.lock);
+			drm_vma_offset_remove(obj->base.dev->vma_offset_manager,
+					      &mmo->vma_node);
+			kfree(mmo);
+			return pos;
+		}
+
+		if (pos->mmap_type < mmo->mmap_type)
+			p = &rb->rb_right;
+		else
+			p = &rb->rb_left;
+	}
+	rb_link_node(&mmo->offset, rb, p);
+	rb_insert_color(&mmo->offset, &obj->mmo.offsets);
+	spin_unlock(&obj->mmo.lock);
+
+	return mmo;
+}
+
+static struct i915_mmap_offset *
+mmap_offset_attach(struct drm_i915_gem_object *obj,
+		   enum i915_mmap_type mmap_type,
+		   struct drm_file *file)
+{
+	struct drm_i915_private *i915 = to_i915(obj->base.dev);
+	struct i915_mmap_offset *mmo;
+	int err;
+
+	GEM_BUG_ON(obj->ops->mmap_offset || obj->ops->mmap_ops);
+
+	mmo = lookup_mmo(obj, mmap_type);
+	if (mmo)
+		goto out;
+
+	mmo = kmalloc(sizeof(*mmo), GFP_KERNEL);
+	if (!mmo)
+		return ERR_PTR(-ENOMEM);
+
+	mmo->obj = obj;
+	mmo->mmap_type = mmap_type;
+	drm_vma_node_reset(&mmo->vma_node);
+
+	err = drm_vma_offset_add(obj->base.dev->vma_offset_manager,
+				 &mmo->vma_node, obj->base.size / PAGE_SIZE);
+	if (likely(!err))
+		goto insert;
+
+	/* Attempt to reap some mmap space from dead objects */
+	err = intel_gt_retire_requests_timeout(to_gt(i915), MAX_SCHEDULE_TIMEOUT,
+					       NULL);
+	if (err)
+		goto err;
+
+	i915_gem_drain_freed_objects(i915);
+	err = drm_vma_offset_add(obj->base.dev->vma_offset_manager,
+				 &mmo->vma_node, obj->base.size / PAGE_SIZE);
+	if (err)
+		goto err;
+
+insert:
+	mmo = insert_mmo(obj, mmo);
+	GEM_BUG_ON(lookup_mmo(obj, mmap_type) != mmo);
+out:
+	if (file)
+		drm_vma_node_allow_once(&mmo->vma_node, file);
+	return mmo;
+
+err:
+	kfree(mmo);
+	return ERR_PTR(err);
+}
+
+static int
+__assign_mmap_offset(struct drm_i915_gem_object *obj,
+		     enum i915_mmap_type mmap_type,
+		     u64 *offset, struct drm_file *file)
+{
+	struct i915_mmap_offset *mmo;
+
+	if (i915_gem_object_never_mmap(obj))
+		return -ENODEV;
+
+	if (obj->ops->mmap_offset)  {
+		if (mmap_type != I915_MMAP_TYPE_FIXED)
+			return -ENODEV;
+
+		*offset = obj->ops->mmap_offset(obj);
+		return 0;
+	}
+
+	if (mmap_type == I915_MMAP_TYPE_FIXED)
+		return -ENODEV;
+
+	if (mmap_type != I915_MMAP_TYPE_GTT &&
+	    !i915_gem_object_has_struct_page(obj) &&
+	    !i915_gem_object_has_iomem(obj))
+		return -ENODEV;
+
+	mmo = mmap_offset_attach(obj, mmap_type, file);
+	if (IS_ERR(mmo))
+		return PTR_ERR(mmo);
+
+	*offset = drm_vma_node_offset_addr(&mmo->vma_node);
+	return 0;
+}
+
+static int
+__assign_mmap_offset_handle(struct drm_file *file,
+			    u32 handle,
+			    enum i915_mmap_type mmap_type,
+			    u64 *offset)
+{
+	struct drm_i915_gem_object *obj;
+	int err;
+
+	obj = i915_gem_object_lookup(file, handle);
+	if (!obj)
+		return -ENOENT;
+
+	err = i915_gem_object_lock_interruptible(obj, NULL);
+	if (err)
+		goto out_put;
+	err = __assign_mmap_offset(obj, mmap_type, offset, file);
+	i915_gem_object_unlock(obj);
+out_put:
+	i915_gem_object_put(obj);
+	return err;
+}
+
+int
+i915_gem_dumb_mmap_offset(struct drm_file *file,
+			  struct drm_device *dev,
+			  u32 handle,
+			  u64 *offset)
+{
+	struct drm_i915_private *i915 = to_i915(dev);
+	enum i915_mmap_type mmap_type;
+
+	if (HAS_LMEM(to_i915(dev)))
+		mmap_type = I915_MMAP_TYPE_FIXED;
+	else if (pat_enabled())
+		mmap_type = I915_MMAP_TYPE_WC;
+	else if (!i915_ggtt_has_aperture(to_gt(i915)->ggtt))
+		return -ENODEV;
+	else
+		mmap_type = I915_MMAP_TYPE_GTT;
+
+	return __assign_mmap_offset_handle(file, handle, mmap_type, offset);
+}
+
+/**
+ * i915_gem_mmap_offset_ioctl - prepare an object for GTT mmap'ing
+ * @dev: DRM device
+ * @data: GTT mapping ioctl data
+ * @file: GEM object info
+ *
+ * Simply returns the fake offset to userspace so it can mmap it.
+ * The mmap call will end up in drm_gem_mmap(), which will set things
+ * up so we can get faults in the handler above.
+ *
+ * The fault handler will take care of binding the object into the GTT
+ * (since it may have been evicted to make room for something), allocating
+ * a fence register, and mapping the appropriate aperture address into
+ * userspace.
+ */
+int
+i915_gem_mmap_offset_ioctl(struct drm_device *dev, void *data,
+			   struct drm_file *file)
+{
+	struct drm_i915_private *i915 = to_i915(dev);
+	struct drm_i915_gem_mmap_offset *args = data;
+	enum i915_mmap_type type;
+	int err;
+
+	/*
+	 * Historically we failed to check args.pad and args.offset
+	 * and so we cannot use those fields for user input and we cannot
+	 * add -EINVAL for them as the ABI is fixed, i.e. old userspace
+	 * may be feeding in garbage in those fields.
+	 *
+	 * if (args->pad) return -EINVAL; is verbotten!
+	 */
+
+	err = i915_user_extensions(u64_to_user_ptr(args->extensions),
+				   NULL, 0, NULL);
+	if (err)
+		return err;
+
+	switch (args->flags) {
+	case I915_MMAP_OFFSET_GTT:
+		if (!i915_ggtt_has_aperture(to_gt(i915)->ggtt))
+			return -ENODEV;
+		type = I915_MMAP_TYPE_GTT;
+		break;
+
+	case I915_MMAP_OFFSET_WC:
+		if (!pat_enabled())
+			return -ENODEV;
+		type = I915_MMAP_TYPE_WC;
+		break;
+
+	case I915_MMAP_OFFSET_WB:
+		type = I915_MMAP_TYPE_WB;
+		break;
+
+	case I915_MMAP_OFFSET_UC:
+		if (!pat_enabled())
+			return -ENODEV;
+		type = I915_MMAP_TYPE_UC;
+		break;
+
+	case I915_MMAP_OFFSET_FIXED:
+		type = I915_MMAP_TYPE_FIXED;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	return __assign_mmap_offset_handle(file, args->handle, type, &args->offset);
+}
+
+static void vm_open(struct vm_area_struct *vma)
+{
+	struct i915_mmap_offset *mmo = vma->vm_private_data;
+	struct drm_i915_gem_object *obj = mmo->obj;
+
+	GEM_BUG_ON(!obj);
+	i915_gem_object_get(obj);
+}
+
+static void vm_close(struct vm_area_struct *vma)
+{
+	struct i915_mmap_offset *mmo = vma->vm_private_data;
+	struct drm_i915_gem_object *obj = mmo->obj;
+
+	GEM_BUG_ON(!obj);
+	i915_gem_object_put(obj);
+}
+
+static const struct vm_operations_struct vm_ops_gtt = {
+	.fault = vm_fault_gtt,
+	.access = vm_access,
+	.open = vm_open,
+	.close = vm_close,
+};
+
+static const struct vm_operations_struct vm_ops_cpu = {
+	.fault = vm_fault_cpu,
+	.access = vm_access,
+	.open = vm_open,
+	.close = vm_close,
+};
+
+static int singleton_release(struct inode *inode, struct file *file)
+{
+	struct drm_i915_private *i915 = file->private_data;
+
+	cmpxchg(&i915->gem.mmap_singleton, file, NULL);
+	drm_dev_put(&i915->drm);
+
+	return 0;
+}
+
+static const struct file_operations singleton_fops = {
+	.owner = THIS_MODULE,
+	.release = singleton_release,
+};
+
+static struct file *mmap_singleton(struct drm_i915_private *i915)
+{
+	struct file *file;
+
+	rcu_read_lock();
+	file = READ_ONCE(i915->gem.mmap_singleton);
+	if (file && !get_file_rcu(file))
+		file = NULL;
+	rcu_read_unlock();
+	if (file)
+		return file;
+
+	file = anon_inode_getfile("i915.gem", &singleton_fops, i915, O_RDWR);
+	if (IS_ERR(file))
+		return file;
+
+	/* Everyone shares a single global address space */
+	file->f_mapping = i915->drm.anon_inode->i_mapping;
+
+	smp_store_mb(i915->gem.mmap_singleton, file);
+	drm_dev_get(&i915->drm);
+
+	return file;
+}
+
+static int
+i915_gem_object_mmap(struct drm_i915_gem_object *obj,
+		     struct i915_mmap_offset *mmo,
+		     struct vm_area_struct *vma)
+{
+	struct drm_i915_private *i915 = to_i915(obj->base.dev);
+	struct drm_device *dev = &i915->drm;
+	struct file *anon;
+
+	if (i915_gem_object_is_readonly(obj)) {
+		if (vma->vm_flags & VM_WRITE) {
+			i915_gem_object_put(obj);
+			return -EINVAL;
+		}
+		vm_flags_clear(vma, VM_MAYWRITE);
+	}
+
+	anon = mmap_singleton(to_i915(dev));
+	if (IS_ERR(anon)) {
+		i915_gem_object_put(obj);
+		return PTR_ERR(anon);
+	}
+
+	vm_flags_set(vma, VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP | VM_IO);
+
+	/*
+	 * We keep the ref on mmo->obj, not vm_file, but we require
+	 * vma->vm_file->f_mapping, see vma_link(), for later revocation.
+	 * Our userspace is accustomed to having per-file resource cleanup
+	 * (i.e. contexts, objects and requests) on their close(fd), which
+	 * requires avoiding extraneous references to their filp, hence why
+	 * we prefer to use an anonymous file for their mmaps.
+	 */
+	vma_set_file(vma, anon);
+	/* Drop the initial creation reference, the vma is now holding one. */
+	fput(anon);
+
+	if (obj->ops->mmap_ops) {
+		vma->vm_page_prot = pgprot_decrypted(vm_get_page_prot(vma->vm_flags));
+		vma->vm_ops = obj->ops->mmap_ops;
+		vma->vm_private_data = obj->base.vma_node.driver_private;
+		return 0;
+	}
+
+	vma->vm_private_data = mmo;
+
+	switch (mmo->mmap_type) {
+	case I915_MMAP_TYPE_WC:
+		vma->vm_page_prot =
+			pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
+		vma->vm_ops = &vm_ops_cpu;
+		break;
+
+	case I915_MMAP_TYPE_FIXED:
+		GEM_WARN_ON(1);
+		fallthrough;
+	case I915_MMAP_TYPE_WB:
+		vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
+		vma->vm_ops = &vm_ops_cpu;
+		break;
+
+	case I915_MMAP_TYPE_UC:
+		vma->vm_page_prot =
+			pgprot_noncached(vm_get_page_prot(vma->vm_flags));
+		vma->vm_ops = &vm_ops_cpu;
+		break;
+
+	case I915_MMAP_TYPE_GTT:
+		vma->vm_page_prot =
+			pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
+		vma->vm_ops = &vm_ops_gtt;
+		break;
+	}
+	vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
+
+	return 0;
+}
+
+/*
+ * This overcomes the limitation in drm_gem_mmap's assignment of a
+ * drm_gem_object as the vma->vm_private_data. Since we need to
+ * be able to resolve multiple mmap offsets which could be tied
+ * to a single gem object.
+ */
+int i915_gem_mmap(struct file *filp, struct vm_area_struct *vma)
+{
+	struct drm_vma_offset_node *node;
+	struct drm_file *priv = filp->private_data;
+	struct drm_device *dev = priv->minor->dev;
+	struct drm_i915_gem_object *obj = NULL;
+	struct i915_mmap_offset *mmo = NULL;
+
+	if (drm_dev_is_unplugged(dev))
+		return -ENODEV;
+
+	rcu_read_lock();
+	drm_vma_offset_lock_lookup(dev->vma_offset_manager);
+	node = drm_vma_offset_exact_lookup_locked(dev->vma_offset_manager,
+						  vma->vm_pgoff,
+						  vma_pages(vma));
+	if (node && drm_vma_node_is_allowed(node, priv)) {
+		/*
+		 * Skip 0-refcnted objects as it is in the process of being
+		 * destroyed and will be invalid when the vma manager lock
+		 * is released.
+		 */
+		if (!node->driver_private) {
+			mmo = container_of(node, struct i915_mmap_offset, vma_node);
+			obj = i915_gem_object_get_rcu(mmo->obj);
+
+			GEM_BUG_ON(obj && obj->ops->mmap_ops);
+		} else {
+			obj = i915_gem_object_get_rcu
+				(container_of(node, struct drm_i915_gem_object,
+					      base.vma_node));
+
+			GEM_BUG_ON(obj && !obj->ops->mmap_ops);
+		}
+	}
+	drm_vma_offset_unlock_lookup(dev->vma_offset_manager);
+	rcu_read_unlock();
+	if (!obj)
+		return node ? -EACCES : -EINVAL;
+
+	return i915_gem_object_mmap(obj, mmo, vma);
+}
+
+int i915_gem_fb_mmap(struct drm_i915_gem_object *obj, struct vm_area_struct *vma)
+{
+	struct drm_i915_private *i915 = to_i915(obj->base.dev);
+	struct drm_device *dev = &i915->drm;
+	struct i915_mmap_offset *mmo = NULL;
+	enum i915_mmap_type mmap_type;
+	struct i915_ggtt *ggtt = to_gt(i915)->ggtt;
+
+	if (drm_dev_is_unplugged(dev))
+		return -ENODEV;
+
+	/* handle ttm object */
+	if (obj->ops->mmap_ops) {
+		/*
+		 * ttm fault handler, ttm_bo_vm_fault_reserved() uses fake offset
+		 * to calculate page offset so set that up.
+		 */
+		vma->vm_pgoff += drm_vma_node_start(&obj->base.vma_node);
+	} else {
+		/* handle stolen and smem objects */
+		mmap_type = i915_ggtt_has_aperture(ggtt) ? I915_MMAP_TYPE_GTT : I915_MMAP_TYPE_WC;
+		mmo = mmap_offset_attach(obj, mmap_type, NULL);
+		if (IS_ERR(mmo))
+			return PTR_ERR(mmo);
+	}
+
+	/*
+	 * When we install vm_ops for mmap we are too late for
+	 * the vm_ops->open() which increases the ref_count of
+	 * this obj and then it gets decreased by the vm_ops->close().
+	 * To balance this increase the obj ref_count here.
+	 */
+	obj = i915_gem_object_get(obj);
+	return i915_gem_object_mmap(obj, mmo, vma);
+}
+
+#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
+#include "selftests/i915_gem_mman.c"
+#endif