/*
 * 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 <linux/dma_remapping.h>
#include <linux/reservation.h>
#include <linux/uaccess.h>

#include <drm/drmP.h>
#include <drm/i915_drm.h>

#include "i915_drv.h"
#include "i915_gem_dmabuf.h"
#include "i915_trace.h"
#include "intel_drv.h"
#include "intel_frontbuffer.h"

#define DBG_USE_CPU_RELOC 0 /* -1 force GTT relocs; 1 force CPU relocs */

#define  __EXEC_OBJECT_HAS_PIN          (1<<31)
#define  __EXEC_OBJECT_HAS_FENCE        (1<<30)
#define  __EXEC_OBJECT_NEEDS_MAP        (1<<29)
#define  __EXEC_OBJECT_NEEDS_BIAS       (1<<28)
#define  __EXEC_OBJECT_INTERNAL_FLAGS (0xf<<28) /* all of the above */

#define BATCH_OFFSET_BIAS (256*1024)

struct i915_execbuffer_params {
        struct drm_device               *dev;
        struct drm_file                 *file;
        struct i915_vma                 *batch;
        u32                             dispatch_flags;
        u32                             args_batch_start_offset;
        struct intel_engine_cs          *engine;
        struct i915_gem_context         *ctx;
        struct drm_i915_gem_request     *request;
};

struct eb_vmas {
        struct drm_i915_private *i915;
        struct list_head vmas;
        int and;
        union {
                struct i915_vma *lut[0];
                struct hlist_head buckets[0];
        };
};

static struct eb_vmas *
eb_create(struct drm_i915_private *i915,
          struct drm_i915_gem_execbuffer2 *args)
{
        struct eb_vmas *eb = NULL;

        if (args->flags & I915_EXEC_HANDLE_LUT) {
                unsigned size = args->buffer_count;
                size *= sizeof(struct i915_vma *);
                size += sizeof(struct eb_vmas);
                eb = kmalloc(size, GFP_TEMPORARY | __GFP_NOWARN | __GFP_NORETRY);
        }

        if (eb == NULL) {
                unsigned size = args->buffer_count;
                unsigned 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_vmas),
                             GFP_TEMPORARY);
                if (eb == NULL)
                        return eb;

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

        eb->i915 = i915;
        INIT_LIST_HEAD(&eb->vmas);
        return eb;
}

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

static struct i915_vma *
eb_get_batch(struct eb_vmas *eb)
{
        struct i915_vma *vma = list_entry(eb->vmas.prev, typeof(*vma), exec_list);

        /*
         * SNA is doing fancy tricks with compressing batch buffers, which leads
         * to negative relocation deltas. Usually that works out ok since the
         * relocate address is still positive, except when the batch is placed
         * very low in the GTT. Ensure this doesn't happen.
         *
         * Note that actual hangs have only been observed on gen7, but for
         * paranoia do it everywhere.
         */
        if ((vma->exec_entry->flags & EXEC_OBJECT_PINNED) == 0)
                vma->exec_entry->flags |= __EXEC_OBJECT_NEEDS_BIAS;

        return vma;
}

static int
eb_lookup_vmas(struct eb_vmas *eb,
               struct drm_i915_gem_exec_object2 *exec,
               const struct drm_i915_gem_execbuffer2 *args,
               struct i915_address_space *vm,
               struct drm_file *file)
{
        struct drm_i915_gem_object *obj;
        struct list_head objects;
        int i, ret;

        INIT_LIST_HEAD(&objects);
        spin_lock(&file->table_lock);
        /* Grab a reference to the object and release the lock so we can lookup
         * or create the VMA without using GFP_ATOMIC */
        for (i = 0; i < args->buffer_count; i++) {
                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);
                        ret = -ENOENT;
                        goto err;
                }

                if (!list_empty(&obj->obj_exec_link)) {
                        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);
                        ret = -EINVAL;
                        goto err;
                }

                i915_gem_object_get(obj);
                list_add_tail(&obj->obj_exec_link, &objects);
        }
        spin_unlock(&file->table_lock);

        i = 0;
        while (!list_empty(&objects)) {
                struct i915_vma *vma;

                obj = list_first_entry(&objects,
                                       struct drm_i915_gem_object,
                                       obj_exec_link);

                /*
                 * NOTE: We can leak any vmas created here when something fails
                 * later on. But that's no issue since vma_unbind can deal with
                 * vmas which are not actually bound. And since only
                 * lookup_or_create exists as an interface to get at the vma
                 * from the (obj, vm) we don't run the risk of creating
                 * duplicated vmas for the same vm.
                 */
                vma = i915_gem_obj_lookup_or_create_vma(obj, vm, NULL);
                if (unlikely(IS_ERR(vma))) {
                        DRM_DEBUG("Failed to lookup VMA\n");
                        ret = PTR_ERR(vma);
                        goto err;
                }

                /* Transfer ownership from the objects list to the vmas list. */
                list_add_tail(&vma->exec_list, &eb->vmas);
                list_del_init(&obj->obj_exec_link);

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

        return 0;


err:
        while (!list_empty(&objects)) {
                obj = list_first_entry(&objects,
                                       struct drm_i915_gem_object,
                                       obj_exec_link);
                list_del_init(&obj->obj_exec_link);
                i915_gem_object_put(obj);
        }
        /*
         * Objects already transfered to the vmas list will be unreferenced by
         * eb_destroy.
         */

        return ret;
}

static struct i915_vma *eb_get_vma(struct eb_vmas *eb, unsigned long handle)
{
        if (eb->and < 0) {
                if (handle >= -eb->and)
                        return NULL;
                return eb->lut[handle];
        } else {
                struct hlist_head *head;
                struct i915_vma *vma;

                head = &eb->buckets[handle & eb->and];
                hlist_for_each_entry(vma, head, exec_node) {
                        if (vma->exec_handle == handle)
                                return vma;
                }
                return NULL;
        }
}

static void
i915_gem_execbuffer_unreserve_vma(struct i915_vma *vma)
{
        struct drm_i915_gem_exec_object2 *entry;

        if (!drm_mm_node_allocated(&vma->node))
                return;

        entry = vma->exec_entry;

        if (entry->flags & __EXEC_OBJECT_HAS_FENCE)
                i915_vma_unpin_fence(vma);

        if (entry->flags & __EXEC_OBJECT_HAS_PIN)
                __i915_vma_unpin(vma);

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

static void eb_destroy(struct eb_vmas *eb)
{
        while (!list_empty(&eb->vmas)) {
                struct i915_vma *vma;

                vma = list_first_entry(&eb->vmas,
                                       struct i915_vma,
                                       exec_list);
                list_del_init(&vma->exec_list);
                i915_gem_execbuffer_unreserve_vma(vma);
                i915_vma_put(vma);
        }
        kfree(eb);
}

static inline int use_cpu_reloc(struct drm_i915_gem_object *obj)
{
        if (!i915_gem_object_has_struct_page(obj))
                return false;

        if (DBG_USE_CPU_RELOC)
                return DBG_USE_CPU_RELOC > 0;

        return (HAS_LLC(obj->base.dev) ||
                obj->base.write_domain == I915_GEM_DOMAIN_CPU ||
                obj->cache_level != I915_CACHE_NONE);
}

/* Used to convert any address to canonical form.
 * Starting from gen8, some commands (e.g. STATE_BASE_ADDRESS,
 * MI_LOAD_REGISTER_MEM and others, see Broadwell PRM Vol2a) require the
 * addresses to be in a canonical form:
 * "GraphicsAddress[63:48] are ignored by the HW and assumed to be in correct
 * canonical form [63:48] == [47]."
 */
#define GEN8_HIGH_ADDRESS_BIT 47
static inline uint64_t gen8_canonical_addr(uint64_t address)
{
        return sign_extend64(address, GEN8_HIGH_ADDRESS_BIT);
}

static inline uint64_t gen8_noncanonical_addr(uint64_t address)
{
        return address & ((1ULL << (GEN8_HIGH_ADDRESS_BIT + 1)) - 1);
}

static inline uint64_t
relocation_target(const struct drm_i915_gem_relocation_entry *reloc,
                  uint64_t target_offset)
{
        return gen8_canonical_addr((int)reloc->delta + target_offset);
}

struct reloc_cache {
        struct drm_i915_private *i915;
        struct drm_mm_node node;
        unsigned long vaddr;
        unsigned int page;
        bool use_64bit_reloc;
};

static void reloc_cache_init(struct reloc_cache *cache,
                             struct drm_i915_private *i915)
{
        cache->page = -1;
        cache->vaddr = 0;
        cache->i915 = i915;
        cache->use_64bit_reloc = INTEL_GEN(cache->i915) >= 8;
        cache->node.allocated = false;
}

static inline void *unmask_page(unsigned long p)
{
        return (void *)(uintptr_t)(p & PAGE_MASK);
}

static inline unsigned int unmask_flags(unsigned long p)
{
        return p & ~PAGE_MASK;
}

#define KMAP 0x4 /* after CLFLUSH_FLAGS */

static void reloc_cache_fini(struct reloc_cache *cache)
{
        void *vaddr;

        if (!cache->vaddr)
                return;

        vaddr = unmask_page(cache->vaddr);
        if (cache->vaddr & KMAP) {
                if (cache->vaddr & CLFLUSH_AFTER)
                        mb();

                kunmap_atomic(vaddr);
                i915_gem_obj_finish_shmem_access((struct drm_i915_gem_object *)cache->node.mm);
        } else {
                wmb();
                io_mapping_unmap_atomic((void __iomem *)vaddr);
                if (cache->node.allocated) {
                        struct i915_ggtt *ggtt = &cache->i915->ggtt;

                        ggtt->base.clear_range(&ggtt->base,
                                               cache->node.start,
                                               cache->node.size,
                                               true);
                        drm_mm_remove_node(&cache->node);
                } else {
                        i915_vma_unpin((struct i915_vma *)cache->node.mm);
                }
        }
}

static void *reloc_kmap(struct drm_i915_gem_object *obj,
                        struct reloc_cache *cache,
                        int page)
{
        void *vaddr;

        if (cache->vaddr) {
                kunmap_atomic(unmask_page(cache->vaddr));
        } else {
                unsigned int flushes;
                int ret;

                ret = i915_gem_obj_prepare_shmem_write(obj, &flushes);
                if (ret)
                        return ERR_PTR(ret);

                BUILD_BUG_ON(KMAP & CLFLUSH_FLAGS);
                BUILD_BUG_ON((KMAP | CLFLUSH_FLAGS) & PAGE_MASK);

                cache->vaddr = flushes | KMAP;
                cache->node.mm = (void *)obj;
                if (flushes)
                        mb();
        }

        vaddr = kmap_atomic(i915_gem_object_get_dirty_page(obj, page));
        cache->vaddr = unmask_flags(cache->vaddr) | (unsigned long)vaddr;
        cache->page = page;

        return vaddr;
}

static void *reloc_iomap(struct drm_i915_gem_object *obj,
                         struct reloc_cache *cache,
                         int page)
{
        struct i915_ggtt *ggtt = &cache->i915->ggtt;
        unsigned long offset;
        void *vaddr;

        if (cache->node.allocated) {
                wmb();
                ggtt->base.insert_page(&ggtt->base,
                                       i915_gem_object_get_dma_address(obj, page),
                                       cache->node.start, I915_CACHE_NONE, 0);
                cache->page = page;
                return unmask_page(cache->vaddr);
        }

        if (cache->vaddr) {
                io_mapping_unmap_atomic(unmask_page(cache->vaddr));
        } else {
                struct i915_vma *vma;
                int ret;

                if (use_cpu_reloc(obj))
                        return NULL;

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

                vma = i915_gem_object_ggtt_pin(obj, NULL, 0, 0,
                                               PIN_MAPPABLE | PIN_NONBLOCK);
                if (IS_ERR(vma)) {
                        memset(&cache->node, 0, sizeof(cache->node));
                        ret = drm_mm_insert_node_in_range_generic
                                (&ggtt->base.mm, &cache->node,
                                 4096, 0, 0,
                                 0, ggtt->mappable_end,
                                 DRM_MM_SEARCH_DEFAULT,
                                 DRM_MM_CREATE_DEFAULT);
                        if (ret) /* no inactive aperture space, use cpu reloc */
                                return NULL;
                } else {
                        ret = i915_vma_put_fence(vma);
                        if (ret) {
                                i915_vma_unpin(vma);
                                return ERR_PTR(ret);
                        }

                        cache->node.start = vma->node.start;
                        cache->node.mm = (void *)vma;
                }
        }

        offset = cache->node.start;
        if (cache->node.allocated) {
                ggtt->base.insert_page(&ggtt->base,
                                       i915_gem_object_get_dma_address(obj, page),
                                       offset, I915_CACHE_NONE, 0);
        } else {
                offset += page << PAGE_SHIFT;
        }

        vaddr = io_mapping_map_atomic_wc(&cache->i915->ggtt.mappable, offset);
        cache->page = page;
        cache->vaddr = (unsigned long)vaddr;

        return vaddr;
}

static void *reloc_vaddr(struct drm_i915_gem_object *obj,
                         struct reloc_cache *cache,
                         int page)
{
        void *vaddr;

        if (cache->page == page) {
                vaddr = unmask_page(cache->vaddr);
        } else {
                vaddr = NULL;
                if ((cache->vaddr & KMAP) == 0)
                        vaddr = reloc_iomap(obj, cache, page);
                if (!vaddr)
                        vaddr = reloc_kmap(obj, cache, page);
        }

        return vaddr;
}

static void clflush_write32(u32 *addr, u32 value, unsigned int flushes)
{
        if (unlikely(flushes & (CLFLUSH_BEFORE | CLFLUSH_AFTER))) {
                if (flushes & CLFLUSH_BEFORE) {
                        clflushopt(addr);
                        mb();
                }

                *addr = value;

                /* Writes to the same cacheline are serialised by the CPU
                 * (including clflush). On the write path, we only require
                 * that it hits memory in an orderly fashion and place
                 * mb barriers at the start and end of the relocation phase
                 * to ensure ordering of clflush wrt to the system.
                 */
                if (flushes & CLFLUSH_AFTER)
                        clflushopt(addr);
        } else
                *addr = value;
}

static int
relocate_entry(struct drm_i915_gem_object *obj,
               const struct drm_i915_gem_relocation_entry *reloc,
               struct reloc_cache *cache,
               u64 target_offset)
{
        u64 offset = reloc->offset;
        bool wide = cache->use_64bit_reloc;
        void *vaddr;

        target_offset = relocation_target(reloc, target_offset);
repeat:
        vaddr = reloc_vaddr(obj, cache, offset >> PAGE_SHIFT);
        if (IS_ERR(vaddr))
                return PTR_ERR(vaddr);

        clflush_write32(vaddr + offset_in_page(offset),
                        lower_32_bits(target_offset),
                        cache->vaddr);

        if (wide) {
                offset += sizeof(u32);
                target_offset >>= 32;
                wide = false;
                goto repeat;
        }

        return 0;
}

static bool object_is_idle(struct drm_i915_gem_object *obj)
{
        unsigned long active = i915_gem_object_get_active(obj);
        int idx;

        for_each_active(active, idx) {
                if (!i915_gem_active_is_idle(&obj->last_read[idx],
                                             &obj->base.dev->struct_mutex))
                        return false;
        }

        return true;
}

static int
i915_gem_execbuffer_relocate_entry(struct drm_i915_gem_object *obj,
                                   struct eb_vmas *eb,
                                   struct drm_i915_gem_relocation_entry *reloc,
                                   struct reloc_cache *cache)
{
        struct drm_device *dev = obj->base.dev;
        struct drm_gem_object *target_obj;
        struct drm_i915_gem_object *target_i915_obj;
        struct i915_vma *target_vma;
        uint64_t target_offset;
        int ret;

        /* we've already hold a reference to all valid objects */
        target_vma = eb_get_vma(eb, reloc->target_handle);
        if (unlikely(target_vma == NULL))
                return -ENOENT;
        target_i915_obj = target_vma->obj;
        target_obj = &target_vma->obj->base;

        target_offset = gen8_canonical_addr(target_vma->node.start);

        /* 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)) {
                ret = i915_vma_bind(target_vma, target_i915_obj->cache_level,
                                    PIN_GLOBAL);
                if (WARN_ONCE(ret, "Unexpected failure to bind target VMA!"))
                        return ret;
        }

        /* 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 -EINVAL;
        }
        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 -EINVAL;
        }

        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 - (cache->use_64bit_reloc ? 8 : 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 -EINVAL;
        }
        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 -EINVAL;
        }

        /* We can't wait for rendering with pagefaults disabled */
        if (pagefault_disabled() && !object_is_idle(obj))
                return -EFAULT;

        ret = relocate_entry(obj, reloc, cache, target_offset);
        if (ret)
                return ret;

        /* and update the user's relocation entry */
        reloc->presumed_offset = target_offset;
        return 0;
}

static int
i915_gem_execbuffer_relocate_vma(struct i915_vma *vma,
                                 struct eb_vmas *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 = vma->exec_entry;
        struct reloc_cache cache;
        int remain, ret = 0;

        user_relocs = u64_to_user_ptr(entry->relocs_ptr);
        reloc_cache_init(&cache, eb->i915);

        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]))) {
                        ret = -EFAULT;
                        goto out;
                }

                do {
                        u64 offset = r->presumed_offset;

                        ret = i915_gem_execbuffer_relocate_entry(vma->obj, eb, r, &cache);
                        if (ret)
                                goto out;

                        if (r->presumed_offset != offset &&
                            __put_user(r->presumed_offset,
                                       &user_relocs->presumed_offset)) {
                                ret = -EFAULT;
                                goto out;
                        }

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

out:
        reloc_cache_fini(&cache);
        return ret;
#undef N_RELOC
}

static int
i915_gem_execbuffer_relocate_vma_slow(struct i915_vma *vma,
                                      struct eb_vmas *eb,
                                      struct drm_i915_gem_relocation_entry *relocs)
{
        const struct drm_i915_gem_exec_object2 *entry = vma->exec_entry;
        struct reloc_cache cache;
        int i, ret = 0;

        reloc_cache_init(&cache, eb->i915);
        for (i = 0; i < entry->relocation_count; i++) {
                ret = i915_gem_execbuffer_relocate_entry(vma->obj, eb, &relocs[i], &cache);
                if (ret)
                        break;
        }
        reloc_cache_fini(&cache);

        return ret;
}

static int
i915_gem_execbuffer_relocate(struct eb_vmas *eb)
{
        struct i915_vma *vma;
        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(vma, &eb->vmas, exec_list) {
                ret = i915_gem_execbuffer_relocate_vma(vma, eb);
                if (ret)
                        break;
        }
        pagefault_enable();

        return ret;
}

static bool only_mappable_for_reloc(unsigned int flags)
{
        return (flags & (EXEC_OBJECT_NEEDS_FENCE | __EXEC_OBJECT_NEEDS_MAP)) ==
                __EXEC_OBJECT_NEEDS_MAP;
}

static int
i915_gem_execbuffer_reserve_vma(struct i915_vma *vma,
                                struct intel_engine_cs *engine,
                                bool *need_reloc)
{
        struct drm_i915_gem_object *obj = vma->obj;
        struct drm_i915_gem_exec_object2 *entry = vma->exec_entry;
        uint64_t flags;
        int ret;

        flags = PIN_USER;
        if (entry->flags & EXEC_OBJECT_NEEDS_GTT)
                flags |= PIN_GLOBAL;

        if (!drm_mm_node_allocated(&vma->node)) {
                /* Wa32bitGeneralStateOffset & Wa32bitInstructionBaseOffset,
                 * limit address to the first 4GBs for unflagged objects.
                 */
                if ((entry->flags & EXEC_OBJECT_SUPPORTS_48B_ADDRESS) == 0)
                        flags |= PIN_ZONE_4G;
                if (entry->flags & __EXEC_OBJECT_NEEDS_MAP)
                        flags |= PIN_GLOBAL | PIN_MAPPABLE;
                if (entry->flags & __EXEC_OBJECT_NEEDS_BIAS)
                        flags |= BATCH_OFFSET_BIAS | PIN_OFFSET_BIAS;
                if (entry->flags & EXEC_OBJECT_PINNED)
                        flags |= entry->offset | PIN_OFFSET_FIXED;
                if ((flags & PIN_MAPPABLE) == 0)
                        flags |= PIN_HIGH;
        }

        ret = i915_vma_pin(vma,
                           entry->pad_to_size,
                           entry->alignment,
                           flags);
        if ((ret == -ENOSPC || ret == -E2BIG) &&
            only_mappable_for_reloc(entry->flags))
                ret = i915_vma_pin(vma,
                                   entry->pad_to_size,
                                   entry->alignment,
                                   flags & ~PIN_MAPPABLE);
        if (ret)
                return ret;

        entry->flags |= __EXEC_OBJECT_HAS_PIN;

        if (entry->flags & EXEC_OBJECT_NEEDS_FENCE) {
                ret = i915_vma_get_fence(vma);
                if (ret)
                        return ret;

                if (i915_vma_pin_fence(vma))
                        entry->flags |= __EXEC_OBJECT_HAS_FENCE;
        }

        if (entry->offset != vma->node.start) {
                entry->offset = vma->node.start;
                *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;
        }

        return 0;
}

static bool
need_reloc_mappable(struct i915_vma *vma)
{
        struct drm_i915_gem_exec_object2 *entry = vma->exec_entry;

        if (entry->relocation_count == 0)
                return false;

        if (!i915_vma_is_ggtt(vma))
                return false;

        /* See also use_cpu_reloc() */
        if (HAS_LLC(vma->obj->base.dev))
                return false;

        if (vma->obj->base.write_domain == I915_GEM_DOMAIN_CPU)
                return false;

        return true;
}

static bool
eb_vma_misplaced(struct i915_vma *vma)
{
        struct drm_i915_gem_exec_object2 *entry = vma->exec_entry;

        WARN_ON(entry->flags & __EXEC_OBJECT_NEEDS_MAP &&
                !i915_vma_is_ggtt(vma));

        if (entry->alignment &&
            vma->node.start & (entry->alignment - 1))
                return true;

        if (vma->node.size < entry->pad_to_size)
                return true;

        if (entry->flags & EXEC_OBJECT_PINNED &&
            vma->node.start != entry->offset)
                return true;

        if (entry->flags & __EXEC_OBJECT_NEEDS_BIAS &&
            vma->node.start < BATCH_OFFSET_BIAS)
                return true;

        /* avoid costly ping-pong once a batch bo ended up non-mappable */
        if (entry->flags & __EXEC_OBJECT_NEEDS_MAP &&
            !i915_vma_is_map_and_fenceable(vma))
                return !only_mappable_for_reloc(entry->flags);

        if ((entry->flags & EXEC_OBJECT_SUPPORTS_48B_ADDRESS) == 0 &&
            (vma->node.start + vma->node.size - 1) >> 32)
                return true;

        return false;
}

static int
i915_gem_execbuffer_reserve(struct intel_engine_cs *engine,
                            struct list_head *vmas,
                            struct i915_gem_context *ctx,
                            bool *need_relocs)
{
        struct drm_i915_gem_object *obj;
        struct i915_vma *vma;
        struct i915_address_space *vm;
        struct list_head ordered_vmas;
        struct list_head pinned_vmas;
        bool has_fenced_gpu_access = INTEL_GEN(engine->i915) < 4;
        int retry;

        vm = list_first_entry(vmas, struct i915_vma, exec_list)->vm;

        INIT_LIST_HEAD(&ordered_vmas);
        INIT_LIST_HEAD(&pinned_vmas);
        while (!list_empty(vmas)) {
                struct drm_i915_gem_exec_object2 *entry;
                bool need_fence, need_mappable;

                vma = list_first_entry(vmas, struct i915_vma, exec_list);
                obj = vma->obj;
                entry = vma->exec_entry;

                if (ctx->flags & CONTEXT_NO_ZEROMAP)
                        entry->flags |= __EXEC_OBJECT_NEEDS_BIAS;

                if (!has_fenced_gpu_access)
                        entry->flags &= ~EXEC_OBJECT_NEEDS_FENCE;
                need_fence =
                        entry->flags & EXEC_OBJECT_NEEDS_FENCE &&
                        i915_gem_object_is_tiled(obj);
                need_mappable = need_fence || need_reloc_mappable(vma);

                if (entry->flags & EXEC_OBJECT_PINNED)
                        list_move_tail(&vma->exec_list, &pinned_vmas);
                else if (need_mappable) {
                        entry->flags |= __EXEC_OBJECT_NEEDS_MAP;
                        list_move(&vma->exec_list, &ordered_vmas);
                } else
                        list_move_tail(&vma->exec_list, &ordered_vmas);

                obj->base.pending_read_domains = I915_GEM_GPU_DOMAINS & ~I915_GEM_DOMAIN_COMMAND;
                obj->base.pending_write_domain = 0;
        }
        list_splice(&ordered_vmas, vmas);
        list_splice(&pinned_vmas, vmas);

        /* 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(vma, vmas, exec_list) {
                        if (!drm_mm_node_allocated(&vma->node))
                                continue;

                        if (eb_vma_misplaced(vma))
                                ret = i915_vma_unbind(vma);
                        else
                                ret = i915_gem_execbuffer_reserve_vma(vma,
                                                                      engine,
                                                                      need_relocs);
                        if (ret)
                                goto err;
                }

                /* Bind fresh objects */
                list_for_each_entry(vma, vmas, exec_list) {
                        if (drm_mm_node_allocated(&vma->node))
                                continue;

                        ret = i915_gem_execbuffer_reserve_vma(vma, engine,
                                                              need_relocs);
                        if (ret)
                                goto err;
                }

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

                /* Decrement pin count for bound objects */
                list_for_each_entry(vma, vmas, exec_list)
                        i915_gem_execbuffer_unreserve_vma(vma);

                ret = i915_gem_evict_vm(vm, true);
                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_engine_cs *engine,

                                  struct eb_vmas *eb,
                                  struct drm_i915_gem_exec_object2 *exec,
                                  struct i915_gem_context *ctx)
{
        struct drm_i915_gem_relocation_entry *reloc;
        struct i915_address_space *vm;
        struct i915_vma *vma;
        bool need_relocs;
        int *reloc_offset;
        int i, total, ret;
        unsigned count = args->buffer_count;

        vm = list_first_entry(&eb->vmas, struct i915_vma, exec_list)->vm;

        /* We may process another execbuffer during the unlock... */
        while (!list_empty(&eb->vmas)) {
                vma = list_first_entry(&eb->vmas, struct i915_vma, exec_list);
                list_del_init(&vma->exec_list);
                i915_gem_execbuffer_unreserve_vma(vma);
                i915_vma_put(vma);
        }

        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 = u64_to_user_ptr(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_vmas(eb, exec, args, vm, file);
        if (ret)
                goto err;

        need_relocs = (args->flags & I915_EXEC_NO_RELOC) == 0;
        ret = i915_gem_execbuffer_reserve(engine, &eb->vmas, ctx,
                                          &need_relocs);
        if (ret)
                goto err;

        list_for_each_entry(vma, &eb->vmas, exec_list) {
                int offset = vma->exec_entry - exec;
                ret = i915_gem_execbuffer_relocate_vma_slow(vma, 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 unsigned int eb_other_engines(struct drm_i915_gem_request *req)
{
        unsigned int mask;

        mask = ~intel_engine_flag(req->engine) & I915_BO_ACTIVE_MASK;
        mask <<= I915_BO_ACTIVE_SHIFT;

        return mask;
}

static int
i915_gem_execbuffer_move_to_gpu(struct drm_i915_gem_request *req,
                                struct list_head *vmas)
{
        const unsigned int other_rings = eb_other_engines(req);
        struct i915_vma *vma;
        int ret;

        list_for_each_entry(vma, vmas, exec_list) {
                struct drm_i915_gem_object *obj = vma->obj;
                struct reservation_object *resv;

                if (obj->flags & other_rings) {
                        ret = i915_gem_request_await_object
                                (req, obj, obj->base.pending_write_domain);
                        if (ret)
                                return ret;
                }

                resv = i915_gem_object_get_dmabuf_resv(obj);
                if (resv) {
                        ret = i915_sw_fence_await_reservation
                                (&req->submit, resv, &i915_fence_ops,
                                 obj->base.pending_write_domain, 10*HZ,
                                 GFP_KERNEL | __GFP_NOWARN);
                        if (ret < 0)
                                return ret;
                }

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

        /* Unconditionally flush any chipset caches (for streaming writes). */
        i915_gem_chipset_flush(req->engine->i915);

        /* Unconditionally invalidate GPU caches and TLBs. */
        return req->engine->emit_flush(req, EMIT_INVALIDATE);
}

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

        /* Kernel clipping was a DRI1 misfeature */
        if (exec->num_cliprects || exec->cliprects_ptr)
                return false;

        if (exec->DR4 == 0xffffffff) {
                DRM_DEBUG("UXA submitting garbage DR4, fixing up\n");
                exec->DR4 = 0;
        }
        if (exec->DR1 || exec->DR4)
                return false;

        if ((exec->batch_start_offset | exec->batch_len) & 0x7)
                return false;

        return true;
}

static int
validate_exec_list(struct drm_device *dev,
                   struct drm_i915_gem_exec_object2 *exec,
                   int count)
{
        unsigned relocs_total = 0;
        unsigned relocs_max = UINT_MAX / sizeof(struct drm_i915_gem_relocation_entry);
        unsigned invalid_flags;
        int i;

        /* INTERNAL flags must not overlap with external ones */
        BUILD_BUG_ON(__EXEC_OBJECT_INTERNAL_FLAGS & ~__EXEC_OBJECT_UNKNOWN_FLAGS);

        invalid_flags = __EXEC_OBJECT_UNKNOWN_FLAGS;
        if (USES_FULL_PPGTT(dev))
                invalid_flags |= EXEC_OBJECT_NEEDS_GTT;

        for (i = 0; i < count; i++) {
                char __user *ptr = u64_to_user_ptr(exec[i].relocs_ptr);
                int length; /* limited by fault_in_pages_readable() */

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

                /* Offset can be used as input (EXEC_OBJECT_PINNED), reject
                 * any non-page-aligned or non-canonical addresses.
                 */
                if (exec[i].flags & EXEC_OBJECT_PINNED) {
                        if (exec[i].offset !=
                            gen8_canonical_addr(exec[i].offset & PAGE_MASK))
                                return -EINVAL;

                        /* From drm_mm perspective address space is continuous,
                         * so from this point we're always using non-canonical
                         * form internally.
                         */
                        exec[i].offset = gen8_noncanonical_addr(exec[i].offset);
                }

                if (exec[i].alignment && !is_power_of_2(exec[i].alignment))
                        return -EINVAL;

                /* pad_to_size was once a reserved field, so sanitize it */
                if (exec[i].flags & EXEC_OBJECT_PAD_TO_SIZE) {
                        if (offset_in_page(exec[i].pad_to_size))
                                return -EINVAL;
                } else {
                        exec[i].pad_to_size = 0;
                }

                /* 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 must check that the entire relocation array is safe
                 * to read, but since we may need to update the presumed
                 * offsets during execution, check for full write access.
                 */
                if (!access_ok(VERIFY_WRITE, ptr, length))
                        return -EFAULT;

                if (likely(!i915.prefault_disable)) {
                        if (fault_in_pages_readable(ptr, length))
                                return -EFAULT;
                }
        }

        return 0;
}

static struct i915_gem_context *
i915_gem_validate_context(struct drm_device *dev, struct drm_file *file,
                          struct intel_engine_cs *engine, const u32 ctx_id)
{
        struct i915_gem_context *ctx;
        struct i915_ctx_hang_stats *hs;

        ctx = i915_gem_context_lookup(file->driver_priv, ctx_id);
        if (IS_ERR(ctx))
                return ctx;

        hs = &ctx->hang_stats;
        if (hs->banned) {
                DRM_DEBUG("Context %u tried to submit while banned\n", ctx_id);
                return ERR_PTR(-EIO);
        }

        return ctx;
}

static bool gpu_write_needs_clflush(struct drm_i915_gem_object *obj)
{
        return !(obj->cache_level == I915_CACHE_NONE ||
                 obj->cache_level == I915_CACHE_WT);
}

void i915_vma_move_to_active(struct i915_vma *vma,
                             struct drm_i915_gem_request *req,
                             unsigned int flags)
{
        struct drm_i915_gem_object *obj = vma->obj;
        const unsigned int idx = req->engine->id;

        GEM_BUG_ON(!drm_mm_node_allocated(&vma->node));

        obj->dirty = 1; /* be paranoid  */

        /* Add a reference if we're newly entering the active list.
         * The order in which we add operations to the retirement queue is
         * vital here: mark_active adds to the start of the callback list,
         * such that subsequent callbacks are called first. Therefore we
         * add the active reference first and queue for it to be dropped
         * *last*.
         */
        if (!i915_gem_object_is_active(obj))
                i915_gem_object_get(obj);
        i915_gem_object_set_active(obj, idx);
        i915_gem_active_set(&obj->last_read[idx], req);

        if (flags & EXEC_OBJECT_WRITE) {
                i915_gem_active_set(&obj->last_write, req);

                intel_fb_obj_invalidate(obj, ORIGIN_CS);

                /* update for the implicit flush after a batch */
                obj->base.write_domain &= ~I915_GEM_GPU_DOMAINS;
                if (!obj->cache_dirty && gpu_write_needs_clflush(obj))
                        obj->cache_dirty = true;
        }

        if (flags & EXEC_OBJECT_NEEDS_FENCE)
                i915_gem_active_set(&vma->last_fence, req);

        i915_vma_set_active(vma, idx);
        i915_gem_active_set(&vma->last_read[idx], req);
        list_move_tail(&vma->vm_link, &vma->vm->active_list);
}

static void eb_export_fence(struct drm_i915_gem_object *obj,
                            struct drm_i915_gem_request *req,
                            unsigned int flags)
{
        struct reservation_object *resv;

        resv = i915_gem_object_get_dmabuf_resv(obj);
        if (!resv)
                return;

        /* Ignore errors from failing to allocate the new fence, we can't
         * handle an error right now. Worst case should be missed
         * synchronisation leading to rendering corruption.
         */
        ww_mutex_lock(&resv->lock, NULL);
        if (flags & EXEC_OBJECT_WRITE)
                reservation_object_add_excl_fence(resv, &req->fence);
        else if (reservation_object_reserve_shared(resv) == 0)
                reservation_object_add_shared_fence(resv, &req->fence);
        ww_mutex_unlock(&resv->lock);
}

static void
i915_gem_execbuffer_move_to_active(struct list_head *vmas,
                                   struct drm_i915_gem_request *req)
{
        struct i915_vma *vma;

        list_for_each_entry(vma, vmas, exec_list) {
                struct drm_i915_gem_object *obj = vma->obj;
                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)
                        vma->exec_entry->flags |= EXEC_OBJECT_WRITE;
                else
                        obj->base.pending_read_domains |= obj->base.read_domains;
                obj->base.read_domains = obj->base.pending_read_domains;

                i915_vma_move_to_active(vma, req, vma->exec_entry->flags);
                eb_export_fence(obj, req, vma->exec_entry->flags);
                trace_i915_gem_object_change_domain(obj, old_read, old_write);
        }
}

static int
i915_reset_gen7_sol_offsets(struct drm_i915_gem_request *req)
{
        struct intel_ring *ring = req->ring;
        int ret, i;

        if (!IS_GEN7(req->i915) || req->engine->id != RCS) {
                DRM_DEBUG("sol reset is gen7/rcs only\n");
                return -EINVAL;
        }

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

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

        intel_ring_advance(ring);

        return 0;
}

static struct i915_vma *
i915_gem_execbuffer_parse(struct intel_engine_cs *engine,
                          struct drm_i915_gem_exec_object2 *shadow_exec_entry,
                          struct drm_i915_gem_object *batch_obj,
                          struct eb_vmas *eb,
                          u32 batch_start_offset,
                          u32 batch_len,
                          bool is_master)
{
        struct drm_i915_gem_object *shadow_batch_obj;
        struct i915_vma *vma;
        int ret;

        shadow_batch_obj = i915_gem_batch_pool_get(&engine->batch_pool,
                                                   PAGE_ALIGN(batch_len));
        if (IS_ERR(shadow_batch_obj))
                return ERR_CAST(shadow_batch_obj);

        ret = intel_engine_cmd_parser(engine,
                                      batch_obj,
                                      shadow_batch_obj,
                                      batch_start_offset,
                                      batch_len,
                                      is_master);
        if (ret) {
                if (ret == -EACCES) /* unhandled chained batch */
                        vma = NULL;
                else
                        vma = ERR_PTR(ret);
                goto out;
        }

        vma = i915_gem_object_ggtt_pin(shadow_batch_obj, NULL, 0, 0, 0);
        if (IS_ERR(vma))
                goto out;

        memset(shadow_exec_entry, 0, sizeof(*shadow_exec_entry));

        vma->exec_entry = shadow_exec_entry;
        vma->exec_entry->flags = __EXEC_OBJECT_HAS_PIN;
        i915_gem_object_get(shadow_batch_obj);
        list_add_tail(&vma->exec_list, &eb->vmas);

out:
        i915_gem_object_unpin_pages(shadow_batch_obj);
        return vma;
}

static int
execbuf_submit(struct i915_execbuffer_params *params,
               struct drm_i915_gem_execbuffer2 *args,
               struct list_head *vmas)
{
        struct drm_i915_private *dev_priv = params->request->i915;
        u64 exec_start, exec_len;
        int instp_mode;
        u32 instp_mask;
        int ret;

        ret = i915_gem_execbuffer_move_to_gpu(params->request, vmas);
        if (ret)
                return ret;

        ret = i915_switch_context(params->request);
        if (ret)
                return ret;

        instp_mode = args->flags & I915_EXEC_CONSTANTS_MASK;
        instp_mask = I915_EXEC_CONSTANTS_MASK;
        switch (instp_mode) {
        case I915_EXEC_CONSTANTS_REL_GENERAL:
        case I915_EXEC_CONSTANTS_ABSOLUTE:
        case I915_EXEC_CONSTANTS_REL_SURFACE:
                if (instp_mode != 0 && params->engine->id != RCS) {
                        DRM_DEBUG("non-0 rel constants mode on non-RCS\n");
                        return -EINVAL;
                }

                if (instp_mode != dev_priv->relative_constants_mode) {
                        if (INTEL_INFO(dev_priv)->gen < 4) {
                                DRM_DEBUG("no rel constants on pre-gen4\n");
                                return -EINVAL;
                        }

                        if (INTEL_INFO(dev_priv)->gen > 5 &&
                            instp_mode == I915_EXEC_CONSTANTS_REL_SURFACE) {
                                DRM_DEBUG("rel surface constants mode invalid on gen5+\n");
                                return -EINVAL;
                        }

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

        if (params->engine->id == RCS &&
            instp_mode != dev_priv->relative_constants_mode) {
                struct intel_ring *ring = params->request->ring;

                ret = intel_ring_begin(params->request, 4);
                if (ret)
                        return ret;

                intel_ring_emit(ring, MI_NOOP);
                intel_ring_emit(ring, MI_LOAD_REGISTER_IMM(1));
                intel_ring_emit_reg(ring, INSTPM);
                intel_ring_emit(ring, instp_mask << 16 | instp_mode);
                intel_ring_advance(ring);

                dev_priv->relative_constants_mode = instp_mode;
        }

        if (args->flags & I915_EXEC_GEN7_SOL_RESET) {
                ret = i915_reset_gen7_sol_offsets(params->request);
                if (ret)
                        return ret;
        }

        exec_len   = args->batch_len;
        exec_start = params->batch->node.start +
                     params->args_batch_start_offset;

        if (exec_len == 0)
                exec_len = params->batch->size - params->args_batch_start_offset;

        ret = params->engine->emit_bb_start(params->request,
                                            exec_start, exec_len,
                                            params->dispatch_flags);
        if (ret)
                return ret;

        trace_i915_gem_ring_dispatch(params->request, params->dispatch_flags);

        i915_gem_execbuffer_move_to_active(vmas, params->request);

        return 0;
}

/**
 * Find one BSD ring to dispatch the corresponding BSD command.
 * The engine index is returned.
 */
static unsigned int
gen8_dispatch_bsd_engine(struct drm_i915_private *dev_priv,
                         struct drm_file *file)
{
        struct drm_i915_file_private *file_priv = file->driver_priv;

        /* Check whether the file_priv has already selected one ring. */
        if ((int)file_priv->bsd_engine < 0)
                file_priv->bsd_engine = atomic_fetch_xor(1,
                         &dev_priv->mm.bsd_engine_dispatch_index);

        return file_priv->bsd_engine;
}

#define I915_USER_RINGS (4)

static const enum intel_engine_id user_ring_map[I915_USER_RINGS + 1] = {
        [I915_EXEC_DEFAULT]     = RCS,
        [I915_EXEC_RENDER]      = RCS,
        [I915_EXEC_BLT]         = BCS,
        [I915_EXEC_BSD]         = VCS,
        [I915_EXEC_VEBOX]       = VECS
};

static struct intel_engine_cs *
eb_select_engine(struct drm_i915_private *dev_priv,
                 struct drm_file *file,
                 struct drm_i915_gem_execbuffer2 *args)
{
        unsigned int user_ring_id = args->flags & I915_EXEC_RING_MASK;
        struct intel_engine_cs *engine;

        if (user_ring_id > I915_USER_RINGS) {
                DRM_DEBUG("execbuf with unknown ring: %u\n", user_ring_id);
                return NULL;
        }

        if ((user_ring_id != I915_EXEC_BSD) &&
            ((args->flags & I915_EXEC_BSD_MASK) != 0)) {
                DRM_DEBUG("execbuf with non bsd ring but with invalid "
                          "bsd dispatch flags: %d\n", (int)(args->flags));
                return NULL;
        }

        if (user_ring_id == I915_EXEC_BSD && HAS_BSD2(dev_priv)) {
                unsigned int bsd_idx = args->flags & I915_EXEC_BSD_MASK;

                if (bsd_idx == I915_EXEC_BSD_DEFAULT) {
                        bsd_idx = gen8_dispatch_bsd_engine(dev_priv, file);
                } else if (bsd_idx >= I915_EXEC_BSD_RING1 &&
                           bsd_idx <= I915_EXEC_BSD_RING2) {
                        bsd_idx >>= I915_EXEC_BSD_SHIFT;
                        bsd_idx--;
                } else {
                        DRM_DEBUG("execbuf with unknown bsd ring: %u\n",
                                  bsd_idx);
                        return NULL;
                }

                engine = &dev_priv->engine[_VCS(bsd_idx)];
        } else {
                engine = &dev_priv->engine[user_ring_map[user_ring_id]];
        }

        if (!intel_engine_initialized(engine)) {
                DRM_DEBUG("execbuf with invalid ring: %u\n", user_ring_id);
                return NULL;
        }

        return engine;
}

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)
{
        struct drm_i915_private *dev_priv = to_i915(dev);
        struct i915_ggtt *ggtt = &dev_priv->ggtt;
        struct eb_vmas *eb;
        struct drm_i915_gem_exec_object2 shadow_exec_entry;
        struct intel_engine_cs *engine;
        struct i915_gem_context *ctx;
        struct i915_address_space *vm;
        struct i915_execbuffer_params params_master; /* XXX: will be removed later */
        struct i915_execbuffer_params *params = &params_master;
        const u32 ctx_id = i915_execbuffer2_get_context_id(*args);
        u32 dispatch_flags;
        int ret;
        bool need_relocs;

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

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

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

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

        engine = eb_select_engine(dev_priv, file, args);
        if (!engine)
                return -EINVAL;

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

        if (args->flags & I915_EXEC_RESOURCE_STREAMER) {
                if (!HAS_RESOURCE_STREAMER(dev)) {
                        DRM_DEBUG("RS is only allowed for Haswell, Gen8 and above\n");
                        return -EINVAL;
                }
                if (engine->id != RCS) {
                        DRM_DEBUG("RS is not available on %s\n",
                                 engine->name);
                        return -EINVAL;
                }

                dispatch_flags |= I915_DISPATCH_RS;
        }

        /* Take a local wakeref for preparing to dispatch the execbuf as
         * we expect to access the hardware fairly frequently in the
         * process. Upon first dispatch, we acquire another prolonged
         * wakeref that we hold until the GPU has been idle for at least
         * 100ms.
         */
        intel_runtime_pm_get(dev_priv);

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

        ctx = i915_gem_validate_context(dev, file, engine, ctx_id);
        if (IS_ERR(ctx)) {
                mutex_unlock(&dev->struct_mutex);
                ret = PTR_ERR(ctx);
                goto pre_mutex_err;
        }

        i915_gem_context_get(ctx);

        if (ctx->ppgtt)
                vm = &ctx->ppgtt->base;
        else
                vm = &ggtt->base;

        memset(&params_master, 0x00, sizeof(params_master));

        eb = eb_create(dev_priv, args);
        if (eb == NULL) {
                i915_gem_context_put(ctx);
                mutex_unlock(&dev->struct_mutex);
                ret = -ENOMEM;
                goto pre_mutex_err;
        }

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

        /* take note of the batch buffer before we might reorder the lists */
        params->batch = eb_get_batch(eb);

        /* 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(engine, &eb->vmas, ctx,
                                          &need_relocs);
        if (ret)
                goto err;

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

        /* Set the pending read domains for the batch buffer to COMMAND */
        if (params->batch->obj->base.pending_write_domain) {
                DRM_DEBUG("Attempting to use self-modifying batch buffer\n");
                ret = -EINVAL;
                goto err;
        }
        if (args->batch_start_offset > params->batch->size ||
            args->batch_len > params->batch->size - args->batch_start_offset) {
                DRM_DEBUG("Attempting to use out-of-bounds batch\n");
                ret = -EINVAL;
                goto err;
        }

        params->args_batch_start_offset = args->batch_start_offset;
        if (intel_engine_needs_cmd_parser(engine) && args->batch_len) {
                struct i915_vma *vma;

                vma = i915_gem_execbuffer_parse(engine, &shadow_exec_entry,
                                                params->batch->obj,
                                                eb,
                                                args->batch_start_offset,
                                                args->batch_len,
                                                drm_is_current_master(file));
                if (IS_ERR(vma)) {
                        ret = PTR_ERR(vma);
                        goto err;
                }

                if (vma) {
                        /*
                         * Batch parsed and accepted:
                         *
                         * Set the DISPATCH_SECURE bit to remove the NON_SECURE
                         * bit from MI_BATCH_BUFFER_START commands issued in
                         * the dispatch_execbuffer implementations. We
                         * specifically don't want that set on batches the
                         * command parser has accepted.
                         */
                        dispatch_flags |= I915_DISPATCH_SECURE;
                        params->args_batch_start_offset = 0;
                        params->batch = vma;
                }
        }

        params->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 bdw mucks it up again. */
        if (dispatch_flags & I915_DISPATCH_SECURE) {
                struct drm_i915_gem_object *obj = params->batch->obj;
                struct i915_vma *vma;

                /*
                 * So on first glance it looks freaky that we pin the batch here
                 * outside of the reservation loop. But:
                 * - The batch is already pinned into the relevant ppgtt, so we
                 *   already have the backing storage fully allocated.
                 * - No other BO uses the global gtt (well contexts, but meh),
                 *   so we don't really have issues with multiple objects not
                 *   fitting due to fragmentation.
                 * So this is actually safe.
                 */
                vma = i915_gem_object_ggtt_pin(obj, NULL, 0, 0, 0);
                if (IS_ERR(vma)) {
                        ret = PTR_ERR(vma);
                        goto err;
                }

                params->batch = vma;
        }

        /* Allocate a request for this batch buffer nice and early. */
        params->request = i915_gem_request_alloc(engine, ctx);
        if (IS_ERR(params->request)) {
                ret = PTR_ERR(params->request);
                goto err_batch_unpin;
        }

        /* Whilst this request exists, batch_obj will be on the
         * active_list, and so will hold the active reference. Only when this
         * request is retired will the the batch_obj be moved onto the
         * inactive_list and lose its active reference. Hence we do not need
         * to explicitly hold another reference here.
         */
        params->request->batch = params->batch;

        ret = i915_gem_request_add_to_client(params->request, file);
        if (ret)
                goto err_request;

        /*
         * Save assorted stuff away to pass through to *_submission().
         * NB: This data should be 'persistent' and not local as it will
         * kept around beyond the duration of the IOCTL once the GPU
         * scheduler arrives.
         */
        params->dev                     = dev;
        params->file                    = file;
        params->engine                    = engine;
        params->dispatch_flags          = dispatch_flags;
        params->ctx                     = ctx;

        ret = execbuf_submit(params, args, &eb->vmas);
err_request:
        __i915_add_request(params->request, ret == 0);

err_batch_unpin:
        /*
         * FIXME: We crucially rely upon the active tracking for the (ppgtt)
         * batch vma for correctness. For less ugly and less fragility this
         * needs to be adjusted to also track the ggtt batch vma properly as
         * active.
         */
        if (dispatch_flags & I915_DISPATCH_SECURE)
                i915_vma_unpin(params->batch);
err:
        /* the request owns the ref now */
        i915_gem_context_put(ctx);
        eb_destroy(eb);

        mutex_unlock(&dev->struct_mutex);

pre_mutex_err:
        /* intel_gpu_busy should also get a ref, so it will free when the device
         * is really idle. */
        intel_runtime_pm_put(dev_priv);
        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,
                             u64_to_user_ptr(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) {
                struct drm_i915_gem_exec_object __user *user_exec_list =
                        u64_to_user_ptr(args->buffers_ptr);

                /* Copy the new buffer offsets back to the user's exec list. */
                for (i = 0; i < args->buffer_count; i++) {
                        exec2_list[i].offset =
                                gen8_canonical_addr(exec2_list[i].offset);
                        ret = __copy_to_user(&user_exec_list[i].offset,
                                             &exec2_list[i].offset,
                                             sizeof(user_exec_list[i].offset));
                        if (ret) {
                                ret = -EFAULT;
                                DRM_DEBUG("failed to copy %d exec entries "
                                          "back to user (%d)\n",
                                          args->buffer_count, ret);
                                break;
                        }
                }
        }

        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;
        }

        if (args->rsvd2 != 0) {
                DRM_DEBUG("dirty rvsd2 field\n");
                return -EINVAL;
        }

        exec2_list = drm_malloc_gfp(args->buffer_count,
                                    sizeof(*exec2_list),
                                    GFP_TEMPORARY);
        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,
                             u64_to_user_ptr(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. */
                struct drm_i915_gem_exec_object2 __user *user_exec_list =
                                   u64_to_user_ptr(args->buffers_ptr);
                int i;

                for (i = 0; i < args->buffer_count; i++) {
                        exec2_list[i].offset =
                                gen8_canonical_addr(exec2_list[i].offset);
                        ret = __copy_to_user(&user_exec_list[i].offset,
                                             &exec2_list[i].offset,
                                             sizeof(user_exec_list[i].offset));
                        if (ret) {
                                ret = -EFAULT;
                                DRM_DEBUG("failed to copy %d exec entries "
                                          "back to user\n",
                                          args->buffer_count);
                                break;
                        }
                }
        }

        drm_free_large(exec2_list);
        return ret;
}