/*
 * Copyright © 2017 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 */

#include <linux/sched/mm.h>

#include "display/intel_frontbuffer.h"
#include "gt/intel_gt.h"
#include "i915_drv.h"
#include "i915_gem_clflush.h"
#include "i915_gem_context.h"
#include "i915_gem_mman.h"
#include "i915_gem_object.h"
#include "i915_globals.h"
#include "i915_trace.h"

static struct i915_global_object {
        struct i915_global base;
        struct kmem_cache *slab_objects;
} global;

struct drm_i915_gem_object *i915_gem_object_alloc(void)
{
        return kmem_cache_zalloc(global.slab_objects, GFP_KERNEL);
}

void i915_gem_object_free(struct drm_i915_gem_object *obj)
{
        return kmem_cache_free(global.slab_objects, obj);
}

void i915_gem_object_init(struct drm_i915_gem_object *obj,
                          const struct drm_i915_gem_object_ops *ops,
                          struct lock_class_key *key)
{
        __mutex_init(&obj->mm.lock, ops->name ?: "obj->mm.lock", key);

        spin_lock_init(&obj->vma.lock);
        INIT_LIST_HEAD(&obj->vma.list);

        INIT_LIST_HEAD(&obj->mm.link);

        INIT_LIST_HEAD(&obj->lut_list);
        spin_lock_init(&obj->lut_lock);

        spin_lock_init(&obj->mmo.lock);
        obj->mmo.offsets = RB_ROOT;

        init_rcu_head(&obj->rcu);

        obj->ops = ops;

        obj->mm.madv = I915_MADV_WILLNEED;
        INIT_RADIX_TREE(&obj->mm.get_page.radix, GFP_KERNEL | __GFP_NOWARN);
        mutex_init(&obj->mm.get_page.lock);

        if (IS_ENABLED(CONFIG_LOCKDEP) && i915_gem_object_is_shrinkable(obj))
                i915_gem_shrinker_taints_mutex(to_i915(obj->base.dev),
                                               &obj->mm.lock);
}

/**
 * Mark up the object's coherency levels for a given cache_level
 * @obj: #drm_i915_gem_object
 * @cache_level: cache level
 */
void i915_gem_object_set_cache_coherency(struct drm_i915_gem_object *obj,
                                         unsigned int cache_level)
{
        obj->cache_level = cache_level;

        if (cache_level != I915_CACHE_NONE)
                obj->cache_coherent = (I915_BO_CACHE_COHERENT_FOR_READ |
                                       I915_BO_CACHE_COHERENT_FOR_WRITE);
        else if (HAS_LLC(to_i915(obj->base.dev)))
                obj->cache_coherent = I915_BO_CACHE_COHERENT_FOR_READ;
        else
                obj->cache_coherent = 0;

        obj->cache_dirty =
                !(obj->cache_coherent & I915_BO_CACHE_COHERENT_FOR_WRITE);
}

void i915_gem_close_object(struct drm_gem_object *gem, struct drm_file *file)
{
        struct drm_i915_gem_object *obj = to_intel_bo(gem);
        struct drm_i915_file_private *fpriv = file->driver_priv;
        struct i915_lut_handle bookmark = {};
        struct i915_mmap_offset *mmo, *mn;
        struct i915_lut_handle *lut, *ln;
        LIST_HEAD(close);

        spin_lock(&obj->lut_lock);
        list_for_each_entry_safe(lut, ln, &obj->lut_list, obj_link) {
                struct i915_gem_context *ctx = lut->ctx;

                if (ctx && ctx->file_priv == fpriv) {
                        i915_gem_context_get(ctx);
                        list_move(&lut->obj_link, &close);
                }

                /* Break long locks, and carefully continue on from this spot */
                if (&ln->obj_link != &obj->lut_list) {
                        list_add_tail(&bookmark.obj_link, &ln->obj_link);
                        if (cond_resched_lock(&obj->lut_lock))
                                list_safe_reset_next(&bookmark, ln, obj_link);
                        __list_del_entry(&bookmark.obj_link);
                }
        }
        spin_unlock(&obj->lut_lock);

        spin_lock(&obj->mmo.lock);
        rbtree_postorder_for_each_entry_safe(mmo, mn, &obj->mmo.offsets, offset)
                drm_vma_node_revoke(&mmo->vma_node, file);
        spin_unlock(&obj->mmo.lock);

        list_for_each_entry_safe(lut, ln, &close, obj_link) {
                struct i915_gem_context *ctx = lut->ctx;
                struct i915_vma *vma;

                /*
                 * We allow the process to have multiple handles to the same
                 * vma, in the same fd namespace, by virtue of flink/open.
                 */

                mutex_lock(&ctx->lut_mutex);
                vma = radix_tree_delete(&ctx->handles_vma, lut->handle);
                if (vma) {
                        GEM_BUG_ON(vma->obj != obj);
                        GEM_BUG_ON(!atomic_read(&vma->open_count));
                        i915_vma_close(vma);
                }
                mutex_unlock(&ctx->lut_mutex);

                i915_gem_context_put(lut->ctx);
                i915_lut_handle_free(lut);
                i915_gem_object_put(obj);
        }
}

static void __i915_gem_free_object_rcu(struct rcu_head *head)
{
        struct drm_i915_gem_object *obj =
                container_of(head, typeof(*obj), rcu);
        struct drm_i915_private *i915 = to_i915(obj->base.dev);

        dma_resv_fini(&obj->base._resv);
        i915_gem_object_free(obj);

        GEM_BUG_ON(!atomic_read(&i915->mm.free_count));
        atomic_dec(&i915->mm.free_count);
}

static void __i915_gem_object_free_mmaps(struct drm_i915_gem_object *obj)
{
        /* Skip serialisation and waking the device if known to be not used. */

        if (obj->userfault_count)
                i915_gem_object_release_mmap_gtt(obj);

        if (!RB_EMPTY_ROOT(&obj->mmo.offsets)) {
                struct i915_mmap_offset *mmo, *mn;

                i915_gem_object_release_mmap_offset(obj);

                rbtree_postorder_for_each_entry_safe(mmo, mn,
                                                     &obj->mmo.offsets,
                                                     offset) {
                        drm_vma_offset_remove(obj->base.dev->vma_offset_manager,
                                              &mmo->vma_node);
                        kfree(mmo);
                }
                obj->mmo.offsets = RB_ROOT;
        }
}

static void __i915_gem_free_objects(struct drm_i915_private *i915,
                                    struct llist_node *freed)
{
        struct drm_i915_gem_object *obj, *on;

        llist_for_each_entry_safe(obj, on, freed, freed) {
                trace_i915_gem_object_destroy(obj);

                if (!list_empty(&obj->vma.list)) {
                        struct i915_vma *vma;

                        /*
                         * Note that the vma keeps an object reference while
                         * it is active, so it *should* not sleep while we
                         * destroy it. Our debug code errs insits it *might*.
                         * For the moment, play along.
                         */
                        spin_lock(&obj->vma.lock);
                        while ((vma = list_first_entry_or_null(&obj->vma.list,
                                                               struct i915_vma,
                                                               obj_link))) {
                                GEM_BUG_ON(vma->obj != obj);
                                spin_unlock(&obj->vma.lock);

                                __i915_vma_put(vma);

                                spin_lock(&obj->vma.lock);
                        }
                        spin_unlock(&obj->vma.lock);
                }

                __i915_gem_object_free_mmaps(obj);

                GEM_BUG_ON(!list_empty(&obj->lut_list));

                atomic_set(&obj->mm.pages_pin_count, 0);
                __i915_gem_object_put_pages(obj);
                GEM_BUG_ON(i915_gem_object_has_pages(obj));
                bitmap_free(obj->bit_17);

                if (obj->base.import_attach)
                        drm_prime_gem_destroy(&obj->base, NULL);

                drm_gem_free_mmap_offset(&obj->base);

                if (obj->ops->release)
                        obj->ops->release(obj);

                /* But keep the pointer alive for RCU-protected lookups */
                call_rcu(&obj->rcu, __i915_gem_free_object_rcu);
                cond_resched();
        }
}

void i915_gem_flush_free_objects(struct drm_i915_private *i915)
{
        struct llist_node *freed = llist_del_all(&i915->mm.free_list);

        if (unlikely(freed))
                __i915_gem_free_objects(i915, freed);
}

static void __i915_gem_free_work(struct work_struct *work)
{
        struct drm_i915_private *i915 =
                container_of(work, struct drm_i915_private, mm.free_work);

        i915_gem_flush_free_objects(i915);
}

void i915_gem_free_object(struct drm_gem_object *gem_obj)
{
        struct drm_i915_gem_object *obj = to_intel_bo(gem_obj);
        struct drm_i915_private *i915 = to_i915(obj->base.dev);

        GEM_BUG_ON(i915_gem_object_is_framebuffer(obj));

        /*
         * Before we free the object, make sure any pure RCU-only
         * read-side critical sections are complete, e.g.
         * i915_gem_busy_ioctl(). For the corresponding synchronized
         * lookup see i915_gem_object_lookup_rcu().
         */
        atomic_inc(&i915->mm.free_count);

        /*
         * This serializes freeing with the shrinker. Since the free
         * is delayed, first by RCU then by the workqueue, we want the
         * shrinker to be able to free pages of unreferenced objects,
         * or else we may oom whilst there are plenty of deferred
         * freed objects.
         */
        i915_gem_object_make_unshrinkable(obj);

        /*
         * Since we require blocking on struct_mutex to unbind the freed
         * object from the GPU before releasing resources back to the
         * system, we can not do that directly from the RCU callback (which may
         * be a softirq context), but must instead then defer that work onto a
         * kthread. We use the RCU callback rather than move the freed object
         * directly onto the work queue so that we can mix between using the
         * worker and performing frees directly from subsequent allocations for
         * crude but effective memory throttling.
         */
        if (llist_add(&obj->freed, &i915->mm.free_list))
                queue_work(i915->wq, &i915->mm.free_work);
}

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_gem_object_flush_write_domain(struct drm_i915_gem_object *obj,
                                   unsigned int flush_domains)
{
        struct i915_vma *vma;

        assert_object_held(obj);

        if (!(obj->write_domain & flush_domains))
                return;

        switch (obj->write_domain) {
        case I915_GEM_DOMAIN_GTT:
                spin_lock(&obj->vma.lock);
                for_each_ggtt_vma(vma, obj) {
                        if (i915_vma_unset_ggtt_write(vma))
                                intel_gt_flush_ggtt_writes(vma->vm->gt);
                }
                spin_unlock(&obj->vma.lock);

                i915_gem_object_flush_frontbuffer(obj, ORIGIN_CPU);
                break;

        case I915_GEM_DOMAIN_WC:
                wmb();
                break;

        case I915_GEM_DOMAIN_CPU:
                i915_gem_clflush_object(obj, I915_CLFLUSH_SYNC);
                break;

        case I915_GEM_DOMAIN_RENDER:
                if (gpu_write_needs_clflush(obj))
                        obj->cache_dirty = true;
                break;
        }

        obj->write_domain = 0;
}

void __i915_gem_object_flush_frontbuffer(struct drm_i915_gem_object *obj,
                                         enum fb_op_origin origin)
{
        struct intel_frontbuffer *front;

        front = __intel_frontbuffer_get(obj);
        if (front) {
                intel_frontbuffer_flush(front, origin);
                intel_frontbuffer_put(front);
        }
}

void __i915_gem_object_invalidate_frontbuffer(struct drm_i915_gem_object *obj,
                                              enum fb_op_origin origin)
{
        struct intel_frontbuffer *front;

        front = __intel_frontbuffer_get(obj);
        if (front) {
                intel_frontbuffer_invalidate(front, origin);
                intel_frontbuffer_put(front);
        }
}

void i915_gem_init__objects(struct drm_i915_private *i915)
{
        INIT_WORK(&i915->mm.free_work, __i915_gem_free_work);
}

static void i915_global_objects_shrink(void)
{
        kmem_cache_shrink(global.slab_objects);
}

static void i915_global_objects_exit(void)
{
        kmem_cache_destroy(global.slab_objects);
}

static struct i915_global_object global = { {
        .shrink = i915_global_objects_shrink,
        .exit = i915_global_objects_exit,
} };

int __init i915_global_objects_init(void)
{
        global.slab_objects =
                KMEM_CACHE(drm_i915_gem_object, SLAB_HWCACHE_ALIGN);
        if (!global.slab_objects)
                return -ENOMEM;

        i915_global_register(&global.base);
        return 0;
}

#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
#include "selftests/huge_gem_object.c"
#include "selftests/huge_pages.c"
#include "selftests/i915_gem_object.c"
#include "selftests/i915_gem_coherency.c"
#endif