/*
 * Copyright © 2008,2010 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>
 *    Chris Wilson <chris@chris-wilson.co.uk>
 *
 */

#include <drm/drmP.h>
#include <drm/i915_drm.h>
#include "i915_drv.h"
#include "i915_trace.h"
#include "intel_drv.h"
#include <linux/dma_remapping.h>

struct eb_objects {
        struct list_head objects;
        int and;
        union {
                struct drm_i915_gem_object *lut[0];
                struct hlist_head buckets[0];
        };
};

static struct eb_objects *
eb_create(struct drm_i915_gem_execbuffer2 *args)
{
        struct eb_objects *eb = NULL;

        if (args->flags & I915_EXEC_HANDLE_LUT) {
                int size = args->buffer_count;
                size *= sizeof(struct drm_i915_gem_object *);
                size += sizeof(struct eb_objects);
                eb = kmalloc(size, GFP_TEMPORARY | __GFP_NOWARN | __GFP_NORETRY);
        }

        if (eb == NULL) {
                int size = args->buffer_count;
                int count = PAGE_SIZE / sizeof(struct hlist_head) / 2;
                BUILD_BUG_ON_NOT_POWER_OF_2(PAGE_SIZE / sizeof(struct hlist_head));
                while (count > 2*size)
                        count >>= 1;
                eb = kzalloc(count*sizeof(struct hlist_head) +
                             sizeof(struct eb_objects),
                             GFP_TEMPORARY);
                if (eb == NULL)
                        return eb;

                eb->and = count - 1;
        } else
                eb->and = -args->buffer_count;

        INIT_LIST_HEAD(&eb->objects);
        return eb;
}

static void
eb_reset(struct eb_objects *eb)
{
        if (eb->and >= 0)
                memset(eb->buckets, 0, (eb->and+1)*sizeof(struct hlist_head));
}

static int
eb_lookup_objects(struct eb_objects *eb,
                  struct drm_i915_gem_exec_object2 *exec,
                  const struct drm_i915_gem_execbuffer2 *args,
                  struct drm_file *file)
{
        int i;

        spin_lock(&file->table_lock);
        for (i = 0; i < args->buffer_count; i++) {
                struct drm_i915_gem_object *obj;

                obj = to_intel_bo(idr_find(&file->object_idr, exec[i].handle));
                if (obj == NULL) {
                        spin_unlock(&file->table_lock);
                        DRM_DEBUG("Invalid object handle %d at index %d\n",
                                   exec[i].handle, i);
                        return -ENOENT;
                }

                if (!list_empty(&obj->exec_list)) {
                        spin_unlock(&file->table_lock);
                        DRM_DEBUG("Object %p [handle %d, index %d] appears more than once in object list\n",
                                   obj, exec[i].handle, i);
                        return -EINVAL;
                }

                drm_gem_object_reference(&obj->base);
                list_add_tail(&obj->exec_list, &eb->objects);

                obj->exec_entry = &exec[i];
                if (eb->and < 0) {
                        eb->lut[i] = obj;
                } else {
                        uint32_t handle = args->flags & I915_EXEC_HANDLE_LUT ? i : exec[i].handle;
                        obj->exec_handle = handle;
                        hlist_add_head(&obj->exec_node,
                                       &eb->buckets[handle & eb->and]);
                }
        }
        spin_unlock(&file->table_lock);

        return 0;
}

static struct drm_i915_gem_object *
eb_get_object(struct eb_objects *eb, unsigned long handle)
{
        if (eb->and < 0) {
                if (handle >= -eb->and)
                        return NULL;
                return eb->lut[handle];
        } else {
                struct hlist_head *head;
                struct hlist_node *node;

                head = &eb->buckets[handle & eb->and];
                hlist_for_each(node, head) {
                        struct drm_i915_gem_object *obj;

                        obj = hlist_entry(node, struct drm_i915_gem_object, exec_node);
                        if (obj->exec_handle == handle)
                                return obj;
                }
                return NULL;
        }
}

static void
eb_destroy(struct eb_objects *eb)
{
        while (!list_empty(&eb->objects)) {
                struct drm_i915_gem_object *obj;

                obj = list_first_entry(&eb->objects,
                                       struct drm_i915_gem_object,
                                       exec_list);
                list_del_init(&obj->exec_list);
                drm_gem_object_unreference(&obj->base);
        }
        kfree(eb);
}

static inline int use_cpu_reloc(struct drm_i915_gem_object *obj)
{
        return (obj->base.write_domain == I915_GEM_DOMAIN_CPU ||
                !obj->map_and_fenceable ||
                obj->cache_level != I915_CACHE_NONE);
}

static int
i915_gem_execbuffer_relocate_entry(struct drm_i915_gem_object *obj,
                                   struct eb_objects *eb,
                                   struct drm_i915_gem_relocation_entry *reloc)
{
        struct drm_device *dev = obj->base.dev;
        struct drm_gem_object *target_obj;
        struct drm_i915_gem_object *target_i915_obj;
        uint32_t target_offset;
        int ret = -EINVAL;

        /* we've already hold a reference to all valid objects */
        target_obj = &eb_get_object(eb, reloc->target_handle)->base;
        if (unlikely(target_obj == NULL))
                return -ENOENT;

        target_i915_obj = to_intel_bo(target_obj);
        target_offset = target_i915_obj->gtt_offset;

        /* Sandybridge PPGTT errata: We need a global gtt mapping for MI and
         * pipe_control writes because the gpu doesn't properly redirect them
         * through the ppgtt for non_secure batchbuffers. */
        if (unlikely(IS_GEN6(dev) &&
            reloc->write_domain == I915_GEM_DOMAIN_INSTRUCTION &&
            !target_i915_obj->has_global_gtt_mapping)) {
                i915_gem_gtt_bind_object(target_i915_obj,
                                         target_i915_obj->cache_level);
        }

        /* Validate that the target is in a valid r/w GPU domain */
        if (unlikely(reloc->write_domain & (reloc->write_domain - 1))) {
                DRM_DEBUG("reloc with multiple write domains: "
                          "obj %p target %d offset %d "
                          "read %08x write %08x",
                          obj, reloc->target_handle,
                          (int) reloc->offset,
                          reloc->read_domains,
                          reloc->write_domain);
                return ret;
        }
        if (unlikely((reloc->write_domain | reloc->read_domains)
                     & ~I915_GEM_GPU_DOMAINS)) {
                DRM_DEBUG("reloc with read/write non-GPU domains: "
                          "obj %p target %d offset %d "
                          "read %08x write %08x",
                          obj, reloc->target_handle,
                          (int) reloc->offset,
                          reloc->read_domains,
                          reloc->write_domain);
                return ret;
        }

        target_obj->pending_read_domains |= reloc->read_domains;
        target_obj->pending_write_domain |= reloc->write_domain;

        /* If the relocation already has the right value in it, no
         * more work needs to be done.
         */
        if (target_offset == reloc->presumed_offset)
                return 0;

        /* Check that the relocation address is valid... */
        if (unlikely(reloc->offset > obj->base.size - 4)) {
                DRM_DEBUG("Relocation beyond object bounds: "
                          "obj %p target %d offset %d size %d.\n",
                          obj, reloc->target_handle,
                          (int) reloc->offset,
                          (int) obj->base.size);
                return ret;
        }
        if (unlikely(reloc->offset & 3)) {
                DRM_DEBUG("Relocation not 4-byte aligned: "
                          "obj %p target %d offset %d.\n",
                          obj, reloc->target_handle,
                          (int) reloc->offset);
                return ret;
        }

        /* We can't wait for rendering with pagefaults disabled */
        if (obj->active && in_atomic())
                return -EFAULT;

        reloc->delta += target_offset;
        if (use_cpu_reloc(obj)) {
                uint32_t page_offset = reloc->offset & ~PAGE_MASK;
                char *vaddr;

                ret = i915_gem_object_set_to_cpu_domain(obj, 1);
                if (ret)
                        return ret;

                vaddr = kmap_atomic(i915_gem_object_get_page(obj,
                                                             reloc->offset >> PAGE_SHIFT));
                *(uint32_t *)(vaddr + page_offset) = reloc->delta;
                kunmap_atomic(vaddr);
        } else {
                struct drm_i915_private *dev_priv = dev->dev_private;
                uint32_t __iomem *reloc_entry;
                void __iomem *reloc_page;

                ret = i915_gem_object_set_to_gtt_domain(obj, true);
                if (ret)
                        return ret;

                ret = i915_gem_object_put_fence(obj);
                if (ret)
                        return ret;

                /* Map the page containing the relocation we're going to perform.  */
                reloc->offset += obj->gtt_offset;
                reloc_page = io_mapping_map_atomic_wc(dev_priv->gtt.mappable,
                                                      reloc->offset & PAGE_MASK);
                reloc_entry = (uint32_t __iomem *)
                        (reloc_page + (reloc->offset & ~PAGE_MASK));
                iowrite32(reloc->delta, reloc_entry);
                io_mapping_unmap_atomic(reloc_page);
        }

        /* and update the user's relocation entry */
        reloc->presumed_offset = target_offset;

        return 0;
}

static int
i915_gem_execbuffer_relocate_object(struct drm_i915_gem_object *obj,
                                    struct eb_objects *eb)
{
#define N_RELOC(x) ((x) / sizeof(struct drm_i915_gem_relocation_entry))
        struct drm_i915_gem_relocation_entry stack_reloc[N_RELOC(512)];
        struct drm_i915_gem_relocation_entry __user *user_relocs;
        struct drm_i915_gem_exec_object2 *entry = obj->exec_entry;
        int remain, ret;

        user_relocs = (void __user *)(uintptr_t)entry->relocs_ptr;

        remain = entry->relocation_count;
        while (remain) {
                struct drm_i915_gem_relocation_entry *r = stack_reloc;
                int count = remain;
                if (count > ARRAY_SIZE(stack_reloc))
                        count = ARRAY_SIZE(stack_reloc);
                remain -= count;

                if (__copy_from_user_inatomic(r, user_relocs, count*sizeof(r[0])))
                        return -EFAULT;

                do {
                        u64 offset = r->presumed_offset;

                        ret = i915_gem_execbuffer_relocate_entry(obj, eb, r);
                        if (ret)
                                return ret;

                        if (r->presumed_offset != offset &&
                            __copy_to_user_inatomic(&user_relocs->presumed_offset,
                                                    &r->presumed_offset,
                                                    sizeof(r->presumed_offset))) {
                                return -EFAULT;
                        }

                        user_relocs++;
                        r++;
                } while (--count);
        }

        return 0;
#undef N_RELOC
}

static int
i915_gem_execbuffer_relocate_object_slow(struct drm_i915_gem_object *obj,
                                         struct eb_objects *eb,
                                         struct drm_i915_gem_relocation_entry *relocs)
{
        const struct drm_i915_gem_exec_object2 *entry = obj->exec_entry;
        int i, ret;

        for (i = 0; i < entry->relocation_count; i++) {
                ret = i915_gem_execbuffer_relocate_entry(obj, eb, &relocs[i]);
                if (ret)
                        return ret;
        }

        return 0;
}

static int
i915_gem_execbuffer_relocate(struct drm_device *dev,
                             struct eb_objects *eb)
{
        struct drm_i915_gem_object *obj;
        int ret = 0;

        /* This is the fast path and we cannot handle a pagefault whilst
         * holding the struct mutex lest the user pass in the relocations
         * contained within a mmaped bo. For in such a case we, the page
         * fault handler would call i915_gem_fault() and we would try to
         * acquire the struct mutex again. Obviously this is bad and so
         * lockdep complains vehemently.
         */
        pagefault_disable();
        list_for_each_entry(obj, &eb->objects, exec_list) {
                ret = i915_gem_execbuffer_relocate_object(obj, eb);
                if (ret)
                        break;
        }
        pagefault_enable();

        return ret;
}

#define  __EXEC_OBJECT_HAS_PIN (1<<31)
#define  __EXEC_OBJECT_HAS_FENCE (1<<30)

static int
need_reloc_mappable(struct drm_i915_gem_object *obj)
{
        struct drm_i915_gem_exec_object2 *entry = obj->exec_entry;
        return entry->relocation_count && !use_cpu_reloc(obj);
}

static int
i915_gem_execbuffer_reserve_object(struct drm_i915_gem_object *obj,
                                   struct intel_ring_buffer *ring,
                                   bool *need_reloc)
{
        struct drm_i915_private *dev_priv = obj->base.dev->dev_private;
        struct drm_i915_gem_exec_object2 *entry = obj->exec_entry;
        bool has_fenced_gpu_access = INTEL_INFO(ring->dev)->gen < 4;
        bool need_fence, need_mappable;
        int ret;

        need_fence =
                has_fenced_gpu_access &&
                entry->flags & EXEC_OBJECT_NEEDS_FENCE &&
                obj->tiling_mode != I915_TILING_NONE;
        need_mappable = need_fence || need_reloc_mappable(obj);

        ret = i915_gem_object_pin(obj, entry->alignment, need_mappable, false);
        if (ret)
                return ret;

        entry->flags |= __EXEC_OBJECT_HAS_PIN;

        if (has_fenced_gpu_access) {
                if (entry->flags & EXEC_OBJECT_NEEDS_FENCE) {
                        ret = i915_gem_object_get_fence(obj);
                        if (ret)
                                return ret;

                        if (i915_gem_object_pin_fence(obj))
                                entry->flags |= __EXEC_OBJECT_HAS_FENCE;

                        obj->pending_fenced_gpu_access = true;
                }
        }

        /* Ensure ppgtt mapping exists if needed */
        if (dev_priv->mm.aliasing_ppgtt && !obj->has_aliasing_ppgtt_mapping) {
                i915_ppgtt_bind_object(dev_priv->mm.aliasing_ppgtt,
                                       obj, obj->cache_level);

                obj->has_aliasing_ppgtt_mapping = 1;
        }

        if (entry->offset != obj->gtt_offset) {
                entry->offset = obj->gtt_offset;
                *need_reloc = true;
        }

        if (entry->flags & EXEC_OBJECT_WRITE) {
                obj->base.pending_read_domains = I915_GEM_DOMAIN_RENDER;
                obj->base.pending_write_domain = I915_GEM_DOMAIN_RENDER;
        }

        if (entry->flags & EXEC_OBJECT_NEEDS_GTT &&
            !obj->has_global_gtt_mapping)
                i915_gem_gtt_bind_object(obj, obj->cache_level);

        return 0;
}

static void
i915_gem_execbuffer_unreserve_object(struct drm_i915_gem_object *obj)
{
        struct drm_i915_gem_exec_object2 *entry;

        if (!obj->gtt_space)
                return;

        entry = obj->exec_entry;

        if (entry->flags & __EXEC_OBJECT_HAS_FENCE)
                i915_gem_object_unpin_fence(obj);

        if (entry->flags & __EXEC_OBJECT_HAS_PIN)
                i915_gem_object_unpin(obj);

        entry->flags &= ~(__EXEC_OBJECT_HAS_FENCE | __EXEC_OBJECT_HAS_PIN);
}

static int
i915_gem_execbuffer_reserve(struct intel_ring_buffer *ring,
                            struct drm_file *file,
                            struct list_head *objects,
                            bool *need_relocs)
{
        struct drm_i915_gem_object *obj;
        struct list_head ordered_objects;
        bool has_fenced_gpu_access = INTEL_INFO(ring->dev)->gen < 4;
        int retry;

        INIT_LIST_HEAD(&ordered_objects);
        while (!list_empty(objects)) {
                struct drm_i915_gem_exec_object2 *entry;
                bool need_fence, need_mappable;

                obj = list_first_entry(objects,
                                       struct drm_i915_gem_object,
                                       exec_list);
                entry = obj->exec_entry;

                need_fence =
                        has_fenced_gpu_access &&
                        entry->flags & EXEC_OBJECT_NEEDS_FENCE &&
                        obj->tiling_mode != I915_TILING_NONE;
                need_mappable = need_fence || need_reloc_mappable(obj);

                if (need_mappable)
                        list_move(&obj->exec_list, &ordered_objects);
                else
                        list_move_tail(&obj->exec_list, &ordered_objects);

                obj->base.pending_read_domains = I915_GEM_GPU_DOMAINS & ~I915_GEM_DOMAIN_COMMAND;
                obj->base.pending_write_domain = 0;
                obj->pending_fenced_gpu_access = false;
        }
        list_splice(&ordered_objects, objects);

        /* Attempt to pin all of the buffers into the GTT.
         * This is done in 3 phases:
         *
         * 1a. Unbind all objects that do not match the GTT constraints for
         *     the execbuffer (fenceable, mappable, alignment etc).
         * 1b. Increment pin count for already bound objects.
         * 2.  Bind new objects.
         * 3.  Decrement pin count.
         *
         * This avoid unnecessary unbinding of later objects in order to make
         * room for the earlier objects *unless* we need to defragment.
         */
        retry = 0;
        do {
                int ret = 0;

                /* Unbind any ill-fitting objects or pin. */
                list_for_each_entry(obj, objects, exec_list) {
                        struct drm_i915_gem_exec_object2 *entry = obj->exec_entry;
                        bool need_fence, need_mappable;

                        if (!obj->gtt_space)
                                continue;

                        need_fence =
                                has_fenced_gpu_access &&
                                entry->flags & EXEC_OBJECT_NEEDS_FENCE &&
                                obj->tiling_mode != I915_TILING_NONE;
                        need_mappable = need_fence || need_reloc_mappable(obj);

                        if ((entry->alignment && obj->gtt_offset & (entry->alignment - 1)) ||
                            (need_mappable && !obj->map_and_fenceable))
                                ret = i915_gem_object_unbind(obj);
                        else
                                ret = i915_gem_execbuffer_reserve_object(obj, ring, need_relocs);
                        if (ret)
                                goto err;
                }

                /* Bind fresh objects */
                list_for_each_entry(obj, objects, exec_list) {
                        if (obj->gtt_space)
                                continue;

                        ret = i915_gem_execbuffer_reserve_object(obj, ring, need_relocs);
                        if (ret)
                                goto err;
                }

err:            /* Decrement pin count for bound objects */
                list_for_each_entry(obj, objects, exec_list)
                        i915_gem_execbuffer_unreserve_object(obj);

                if (ret != -ENOSPC || retry++)
                        return ret;

                ret = i915_gem_evict_everything(ring->dev);
                if (ret)
                        return ret;
        } while (1);
}

static int
i915_gem_execbuffer_relocate_slow(struct drm_device *dev,
                                  struct drm_i915_gem_execbuffer2 *args,
                                  struct drm_file *file,
                                  struct intel_ring_buffer *ring,
                                  struct eb_objects *eb,
                                  struct drm_i915_gem_exec_object2 *exec)
{
        struct drm_i915_gem_relocation_entry *reloc;
        struct drm_i915_gem_object *obj;
        bool need_relocs;
        int *reloc_offset;
        int i, total, ret;
        int count = args->buffer_count;

        /* We may process another execbuffer during the unlock... */
        while (!list_empty(&eb->objects)) {
                obj = list_first_entry(&eb->objects,
                                       struct drm_i915_gem_object,
                                       exec_list);
                list_del_init(&obj->exec_list);
                drm_gem_object_unreference(&obj->base);
        }

        mutex_unlock(&dev->struct_mutex);

        total = 0;
        for (i = 0; i < count; i++)
                total += exec[i].relocation_count;

        reloc_offset = drm_malloc_ab(count, sizeof(*reloc_offset));
        reloc = drm_malloc_ab(total, sizeof(*reloc));
        if (reloc == NULL || reloc_offset == NULL) {
                drm_free_large(reloc);
                drm_free_large(reloc_offset);
                mutex_lock(&dev->struct_mutex);
                return -ENOMEM;
        }

        total = 0;
        for (i = 0; i < count; i++) {
                struct drm_i915_gem_relocation_entry __user *user_relocs;
                u64 invalid_offset = (u64)-1;
                int j;

                user_relocs = (void __user *)(uintptr_t)exec[i].relocs_ptr;

                if (copy_from_user(reloc+total, user_relocs,
                                   exec[i].relocation_count * sizeof(*reloc))) {
                        ret = -EFAULT;
                        mutex_lock(&dev->struct_mutex);
                        goto err;
                }

                /* As we do not update the known relocation offsets after
                 * relocating (due to the complexities in lock handling),
                 * we need to mark them as invalid now so that we force the
                 * relocation processing next time. Just in case the target
                 * object is evicted and then rebound into its old
                 * presumed_offset before the next execbuffer - if that
                 * happened we would make the mistake of assuming that the
                 * relocations were valid.
                 */
                for (j = 0; j < exec[i].relocation_count; j++) {
                        if (copy_to_user(&user_relocs[j].presumed_offset,
                                         &invalid_offset,
                                         sizeof(invalid_offset))) {
                                ret = -EFAULT;
                                mutex_lock(&dev->struct_mutex);
                                goto err;
                        }
                }

                reloc_offset[i] = total;
                total += exec[i].relocation_count;
        }

        ret = i915_mutex_lock_interruptible(dev);
        if (ret) {
                mutex_lock(&dev->struct_mutex);
                goto err;
        }

        /* reacquire the objects */
        eb_reset(eb);
        ret = eb_lookup_objects(eb, exec, args, file);
        if (ret)
                goto err;

        need_relocs = (args->flags & I915_EXEC_NO_RELOC) == 0;
        ret = i915_gem_execbuffer_reserve(ring, file, &eb->objects, &need_relocs);
        if (ret)
                goto err;

        list_for_each_entry(obj, &eb->objects, exec_list) {
                int offset = obj->exec_entry - exec;
                ret = i915_gem_execbuffer_relocate_object_slow(obj, eb,
                                                               reloc + reloc_offset[offset]);
                if (ret)
                        goto err;
        }

        /* Leave the user relocations as are, this is the painfully slow path,
         * and we want to avoid the complication of dropping the lock whilst
         * having buffers reserved in the aperture and so causing spurious
         * ENOSPC for random operations.
         */

err:
        drm_free_large(reloc);
        drm_free_large(reloc_offset);
        return ret;
}

static int
i915_gem_execbuffer_move_to_gpu(struct intel_ring_buffer *ring,
                                struct list_head *objects)
{
        struct drm_i915_gem_object *obj;
        uint32_t flush_domains = 0;
        int ret;

        list_for_each_entry(obj, objects, exec_list) {
                ret = i915_gem_object_sync(obj, ring);
                if (ret)
                        return ret;

                if (obj->base.write_domain & I915_GEM_DOMAIN_CPU)
                        i915_gem_clflush_object(obj);

                flush_domains |= obj->base.write_domain;
        }

        if (flush_domains & I915_GEM_DOMAIN_CPU)
                i915_gem_chipset_flush(ring->dev);

        if (flush_domains & I915_GEM_DOMAIN_GTT)
                wmb();

        /* Unconditionally invalidate gpu caches and ensure that we do flush
         * any residual writes from the previous batch.
         */
        return intel_ring_invalidate_all_caches(ring);
}

static bool
i915_gem_check_execbuffer(struct drm_i915_gem_execbuffer2 *exec)
{
        if (exec->flags & __I915_EXEC_UNKNOWN_FLAGS)
                return false;

        return ((exec->batch_start_offset | exec->batch_len) & 0x7) == 0;
}

static int
validate_exec_list(struct drm_i915_gem_exec_object2 *exec,
                   int count)
{
        int i;
        int relocs_total = 0;
        int relocs_max = INT_MAX / sizeof(struct drm_i915_gem_relocation_entry);

        for (i = 0; i < count; i++) {
                char __user *ptr = (char __user *)(uintptr_t)exec[i].relocs_ptr;
                int length; /* limited by fault_in_pages_readable() */

                if (exec[i].flags & __EXEC_OBJECT_UNKNOWN_FLAGS)
                        return -EINVAL;

                /* First check for malicious input causing overflow in
                 * the worst case where we need to allocate the entire
                 * relocation tree as a single array.
                 */
                if (exec[i].relocation_count > relocs_max - relocs_total)
                        return -EINVAL;
                relocs_total += exec[i].relocation_count;

                length = exec[i].relocation_count *
                        sizeof(struct drm_i915_gem_relocation_entry);
                /* we may also need to update the presumed offsets */
                if (!access_ok(VERIFY_WRITE, ptr, length))
                        return -EFAULT;

                if (fault_in_multipages_readable(ptr, length))
                        return -EFAULT;
        }

        return 0;
}

static void
i915_gem_execbuffer_move_to_active(struct list_head *objects,
                                   struct intel_ring_buffer *ring)
{
        struct drm_i915_gem_object *obj;

        list_for_each_entry(obj, objects, exec_list) {
                u32 old_read = obj->base.read_domains;
                u32 old_write = obj->base.write_domain;

                obj->base.write_domain = obj->base.pending_write_domain;
                if (obj->base.write_domain == 0)
                        obj->base.pending_read_domains |= obj->base.read_domains;
                obj->base.read_domains = obj->base.pending_read_domains;
                obj->fenced_gpu_access = obj->pending_fenced_gpu_access;

                i915_gem_object_move_to_active(obj, ring);
                if (obj->base.write_domain) {
                        obj->dirty = 1;
                        obj->last_write_seqno = intel_ring_get_seqno(ring);
                        if (obj->pin_count) /* check for potential scanout */
                                intel_mark_fb_busy(obj);
                }

                trace_i915_gem_object_change_domain(obj, old_read, old_write);
        }
}

static void
i915_gem_execbuffer_retire_commands(struct drm_device *dev,
                                    struct drm_file *file,
                                    struct intel_ring_buffer *ring)
{
        /* Unconditionally force add_request to emit a full flush. */
        ring->gpu_caches_dirty = true;

        /* Add a breadcrumb for the completion of the batch buffer */
        (void)i915_add_request(ring, file, NULL);
}

static int
i915_reset_gen7_sol_offsets(struct drm_device *dev,
                            struct intel_ring_buffer *ring)
{
        drm_i915_private_t *dev_priv = dev->dev_private;
        int ret, i;

        if (!IS_GEN7(dev) || ring != &dev_priv->ring[RCS])
                return 0;

        ret = intel_ring_begin(ring, 4 * 3);
        if (ret)
                return ret;

        for (i = 0; i < 4; i++) {
                intel_ring_emit(ring, MI_LOAD_REGISTER_IMM(1));
                intel_ring_emit(ring, GEN7_SO_WRITE_OFFSET(i));
                intel_ring_emit(ring, 0);
        }

        intel_ring_advance(ring);

        return 0;
}

static int
i915_gem_do_execbuffer(struct drm_device *dev, void *data,
                       struct drm_file *file,
                       struct drm_i915_gem_execbuffer2 *args,
                       struct drm_i915_gem_exec_object2 *exec)
{
        drm_i915_private_t *dev_priv = dev->dev_private;
        struct eb_objects *eb;
        struct drm_i915_gem_object *batch_obj;
        struct drm_clip_rect *cliprects = NULL;
        struct intel_ring_buffer *ring;
        u32 ctx_id = i915_execbuffer2_get_context_id(*args);
        u32 exec_start, exec_len;
        u32 mask, flags;
        int ret, mode, i;
        bool need_relocs;

        if (!i915_gem_check_execbuffer(args))
                return -EINVAL;

        ret = validate_exec_list(exec, args->buffer_count);
        if (ret)
                return ret;

        flags = 0;
        if (args->flags & I915_EXEC_SECURE) {
                if (!file->is_master || !capable(CAP_SYS_ADMIN))
                    return -EPERM;

                flags |= I915_DISPATCH_SECURE;
        }
        if (args->flags & I915_EXEC_IS_PINNED)
                flags |= I915_DISPATCH_PINNED;

        switch (args->flags & I915_EXEC_RING_MASK) {
        case I915_EXEC_DEFAULT:
        case I915_EXEC_RENDER:
                ring = &dev_priv->ring[RCS];
                break;
        case I915_EXEC_BSD:
                ring = &dev_priv->ring[VCS];
                if (ctx_id != 0) {
                        DRM_DEBUG("Ring %s doesn't support contexts\n",
                                  ring->name);
                        return -EPERM;
                }
                break;
        case I915_EXEC_BLT:
                ring = &dev_priv->ring[BCS];
                if (ctx_id != 0) {
                        DRM_DEBUG("Ring %s doesn't support contexts\n",
                                  ring->name);
                        return -EPERM;
                }
                break;
        default:
                DRM_DEBUG("execbuf with unknown ring: %d\n",
                          (int)(args->flags & I915_EXEC_RING_MASK));
                return -EINVAL;
        }
        if (!intel_ring_initialized(ring)) {
                DRM_DEBUG("execbuf with invalid ring: %d\n",
                          (int)(args->flags & I915_EXEC_RING_MASK));
                return -EINVAL;
        }

        mode = args->flags & I915_EXEC_CONSTANTS_MASK;
        mask = I915_EXEC_CONSTANTS_MASK;
        switch (mode) {
        case I915_EXEC_CONSTANTS_REL_GENERAL:
        case I915_EXEC_CONSTANTS_ABSOLUTE:
        case I915_EXEC_CONSTANTS_REL_SURFACE:
                if (ring == &dev_priv->ring[RCS] &&
                    mode != dev_priv->relative_constants_mode) {
                        if (INTEL_INFO(dev)->gen < 4)
                                return -EINVAL;

                        if (INTEL_INFO(dev)->gen > 5 &&
                            mode == I915_EXEC_CONSTANTS_REL_SURFACE)
                                return -EINVAL;

                        /* The HW changed the meaning on this bit on gen6 */
                        if (INTEL_INFO(dev)->gen >= 6)
                                mask &= ~I915_EXEC_CONSTANTS_REL_SURFACE;
                }
                break;
        default:
                DRM_DEBUG("execbuf with unknown constants: %d\n", mode);
                return -EINVAL;
        }

        if (args->buffer_count < 1) {
                DRM_DEBUG("execbuf with %d buffers\n", args->buffer_count);
                return -EINVAL;
        }

        if (args->num_cliprects != 0) {
                if (ring != &dev_priv->ring[RCS]) {
                        DRM_DEBUG("clip rectangles are only valid with the render ring\n");
                        return -EINVAL;
                }

                if (INTEL_INFO(dev)->gen >= 5) {
                        DRM_DEBUG("clip rectangles are only valid on pre-gen5\n");
                        return -EINVAL;
                }

                if (args->num_cliprects > UINT_MAX / sizeof(*cliprects)) {
                        DRM_DEBUG("execbuf with %u cliprects\n",
                                  args->num_cliprects);
                        return -EINVAL;
                }

                cliprects = kmalloc(args->num_cliprects * sizeof(*cliprects),
                                    GFP_KERNEL);
                if (cliprects == NULL) {
                        ret = -ENOMEM;
                        goto pre_mutex_err;
                }

                if (copy_from_user(cliprects,
                                     (struct drm_clip_rect __user *)(uintptr_t)
                                     args->cliprects_ptr,
                                     sizeof(*cliprects)*args->num_cliprects)) {
                        ret = -EFAULT;
                        goto pre_mutex_err;
                }
        }

        ret = i915_mutex_lock_interruptible(dev);
        if (ret)
                goto pre_mutex_err;

        if (dev_priv->mm.suspended) {
                mutex_unlock(&dev->struct_mutex);
                ret = -EBUSY;
                goto pre_mutex_err;
        }

        eb = eb_create(args);
        if (eb == NULL) {
                mutex_unlock(&dev->struct_mutex);
                ret = -ENOMEM;
                goto pre_mutex_err;
        }

        /* Look up object handles */
        ret = eb_lookup_objects(eb, exec, args, file);
        if (ret)
                goto err;

        /* take note of the batch buffer before we might reorder the lists */
        batch_obj = list_entry(eb->objects.prev,
                               struct drm_i915_gem_object,
                               exec_list);

        /* Move the objects en-masse into the GTT, evicting if necessary. */
        need_relocs = (args->flags & I915_EXEC_NO_RELOC) == 0;
        ret = i915_gem_execbuffer_reserve(ring, file, &eb->objects, &need_relocs);
        if (ret)
                goto err;

        /* The objects are in their final locations, apply the relocations. */
        if (need_relocs)
                ret = i915_gem_execbuffer_relocate(dev, eb);
        if (ret) {
                if (ret == -EFAULT) {
                        ret = i915_gem_execbuffer_relocate_slow(dev, args, file, ring,
                                                                eb, exec);
                        BUG_ON(!mutex_is_locked(&dev->struct_mutex));

                }
                if (ret)
                        goto err;
        }

        /* Set the pending read domains for the batch buffer to COMMAND */
        if (batch_obj->base.pending_write_domain) {
                DRM_DEBUG("Attempting to use self-modifying batch buffer\n");
                ret = -EINVAL;
                goto err;
        }
        batch_obj->base.pending_read_domains |= I915_GEM_DOMAIN_COMMAND;

        /* snb/ivb/vlv conflate the "batch in ppgtt" bit with the "non-secure
         * batch" bit. Hence we need to pin secure batches into the global gtt.
         * hsw should have this fixed, but let's be paranoid and do it
         * unconditionally for now. */
        if (flags & I915_DISPATCH_SECURE && !batch_obj->has_global_gtt_mapping)
                i915_gem_gtt_bind_object(batch_obj, batch_obj->cache_level);

        ret = i915_gem_execbuffer_move_to_gpu(ring, &eb->objects);
        if (ret)
                goto err;

        ret = i915_switch_context(ring, file, ctx_id);
        if (ret)
                goto err;

        if (ring == &dev_priv->ring[RCS] &&
            mode != dev_priv->relative_constants_mode) {
                ret = intel_ring_begin(ring, 4);
                if (ret)
                                goto err;

                intel_ring_emit(ring, MI_NOOP);
                intel_ring_emit(ring, MI_LOAD_REGISTER_IMM(1));
                intel_ring_emit(ring, INSTPM);
                intel_ring_emit(ring, mask << 16 | mode);
                intel_ring_advance(ring);

                dev_priv->relative_constants_mode = mode;
        }

        if (args->flags & I915_EXEC_GEN7_SOL_RESET) {
                ret = i915_reset_gen7_sol_offsets(dev, ring);
                if (ret)
                        goto err;
        }

        exec_start = batch_obj->gtt_offset + args->batch_start_offset;
        exec_len = args->batch_len;
        if (cliprects) {
                for (i = 0; i < args->num_cliprects; i++) {
                        ret = i915_emit_box(dev, &cliprects[i],
                                            args->DR1, args->DR4);
                        if (ret)
                                goto err;

                        ret = ring->dispatch_execbuffer(ring,
                                                        exec_start, exec_len,
                                                        flags);
                        if (ret)
                                goto err;
                }
        } else {
                ret = ring->dispatch_execbuffer(ring,
                                                exec_start, exec_len,
                                                flags);
                if (ret)
                        goto err;
        }

        trace_i915_gem_ring_dispatch(ring, intel_ring_get_seqno(ring), flags);

        i915_gem_execbuffer_move_to_active(&eb->objects, ring);
        i915_gem_execbuffer_retire_commands(dev, file, ring);

err:
        eb_destroy(eb);

        mutex_unlock(&dev->struct_mutex);

pre_mutex_err:
        kfree(cliprects);
        return ret;
}

/*
 * Legacy execbuffer just creates an exec2 list from the original exec object
 * list array and passes it to the real function.
 */
int
i915_gem_execbuffer(struct drm_device *dev, void *data,
                    struct drm_file *file)
{
        struct drm_i915_gem_execbuffer *args = data;
        struct drm_i915_gem_execbuffer2 exec2;
        struct drm_i915_gem_exec_object *exec_list = NULL;
        struct drm_i915_gem_exec_object2 *exec2_list = NULL;
        int ret, i;

        if (args->buffer_count < 1) {
                DRM_DEBUG("execbuf with %d buffers\n", args->buffer_count);
                return -EINVAL;
        }

        /* Copy in the exec list from userland */
        exec_list = drm_malloc_ab(sizeof(*exec_list), args->buffer_count);
        exec2_list = drm_malloc_ab(sizeof(*exec2_list), args->buffer_count);
        if (exec_list == NULL || exec2_list == NULL) {
                DRM_DEBUG("Failed to allocate exec list for %d buffers\n",
                          args->buffer_count);
                drm_free_large(exec_list);
                drm_free_large(exec2_list);
                return -ENOMEM;
        }
        ret = copy_from_user(exec_list,
                             (void __user *)(uintptr_t)args->buffers_ptr,
                             sizeof(*exec_list) * args->buffer_count);
        if (ret != 0) {
                DRM_DEBUG("copy %d exec entries failed %d\n",
                          args->buffer_count, ret);
                drm_free_large(exec_list);
                drm_free_large(exec2_list);
                return -EFAULT;
        }

        for (i = 0; i < args->buffer_count; i++) {
                exec2_list[i].handle = exec_list[i].handle;
                exec2_list[i].relocation_count = exec_list[i].relocation_count;
                exec2_list[i].relocs_ptr = exec_list[i].relocs_ptr;
                exec2_list[i].alignment = exec_list[i].alignment;
                exec2_list[i].offset = exec_list[i].offset;
                if (INTEL_INFO(dev)->gen < 4)
                        exec2_list[i].flags = EXEC_OBJECT_NEEDS_FENCE;
                else
                        exec2_list[i].flags = 0;
        }

        exec2.buffers_ptr = args->buffers_ptr;
        exec2.buffer_count = args->buffer_count;
        exec2.batch_start_offset = args->batch_start_offset;
        exec2.batch_len = args->batch_len;
        exec2.DR1 = args->DR1;
        exec2.DR4 = args->DR4;
        exec2.num_cliprects = args->num_cliprects;
        exec2.cliprects_ptr = args->cliprects_ptr;
        exec2.flags = I915_EXEC_RENDER;
        i915_execbuffer2_set_context_id(exec2, 0);

        ret = i915_gem_do_execbuffer(dev, data, file, &exec2, exec2_list);
        if (!ret) {
                /* Copy the new buffer offsets back to the user's exec list. */
                for (i = 0; i < args->buffer_count; i++)
                        exec_list[i].offset = exec2_list[i].offset;
                /* ... and back out to userspace */
                ret = copy_to_user((void __user *)(uintptr_t)args->buffers_ptr,
                                   exec_list,
                                   sizeof(*exec_list) * args->buffer_count);
                if (ret) {
                        ret = -EFAULT;
                        DRM_DEBUG("failed to copy %d exec entries "
                                  "back to user (%d)\n",
                                  args->buffer_count, ret);
                }
        }

        drm_free_large(exec_list);
        drm_free_large(exec2_list);
        return ret;
}

int
i915_gem_execbuffer2(struct drm_device *dev, void *data,
                     struct drm_file *file)
{
        struct drm_i915_gem_execbuffer2 *args = data;
        struct drm_i915_gem_exec_object2 *exec2_list = NULL;
        int ret;

        if (args->buffer_count < 1 ||
            args->buffer_count > UINT_MAX / sizeof(*exec2_list)) {
                DRM_DEBUG("execbuf2 with %d buffers\n", args->buffer_count);
                return -EINVAL;
        }

        exec2_list = kmalloc(sizeof(*exec2_list)*args->buffer_count,
                             GFP_TEMPORARY | __GFP_NOWARN | __GFP_NORETRY);
        if (exec2_list == NULL)
                exec2_list = drm_malloc_ab(sizeof(*exec2_list),
                                           args->buffer_count);
        if (exec2_list == NULL) {
                DRM_DEBUG("Failed to allocate exec list for %d buffers\n",
                          args->buffer_count);
                return -ENOMEM;
        }
        ret = copy_from_user(exec2_list,
                             (struct drm_i915_relocation_entry __user *)
                             (uintptr_t) args->buffers_ptr,
                             sizeof(*exec2_list) * args->buffer_count);
        if (ret != 0) {
                DRM_DEBUG("copy %d exec entries failed %d\n",
                          args->buffer_count, ret);
                drm_free_large(exec2_list);
                return -EFAULT;
        }

        ret = i915_gem_do_execbuffer(dev, data, file, args, exec2_list);
        if (!ret) {
                /* Copy the new buffer offsets back to the user's exec list. */
                ret = copy_to_user((void __user *)(uintptr_t)args->buffers_ptr,
                                   exec2_list,
                                   sizeof(*exec2_list) * args->buffer_count);
                if (ret) {
                        ret = -EFAULT;
                        DRM_DEBUG("failed to copy %d exec entries "
                                  "back to user (%d)\n",
                                  args->buffer_count, ret);
                }
        }

        drm_free_large(exec2_list);
        return ret;
}