/*
 * Copyright © 2008-2015 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 * Authors:
 *    Eric Anholt <eric@anholt.net>
 *
 */

#include <drm/drm_vma_manager.h>
#include <linux/dma-fence-array.h>
#include <linux/kthread.h>
#include <linux/dma-resv.h>
#include <linux/shmem_fs.h>
#include <linux/slab.h>
#include <linux/stop_machine.h>
#include <linux/swap.h>
#include <linux/pci.h>
#include <linux/dma-buf.h>
#include <linux/mman.h>

#include "display/intel_display.h"
#include "display/intel_frontbuffer.h"

#include "gem/i915_gem_clflush.h"
#include "gem/i915_gem_context.h"
#include "gem/i915_gem_ioctls.h"
#include "gem/i915_gem_mman.h"
#include "gem/i915_gem_region.h"
#include "gt/intel_engine_user.h"
#include "gt/intel_gt.h"
#include "gt/intel_gt_pm.h"
#include "gt/intel_workarounds.h"

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

#include "intel_pm.h"

static int
insert_mappable_node(struct i915_ggtt *ggtt, struct drm_mm_node *node, u32 size)
{
        int err;

        err = mutex_lock_interruptible(&ggtt->vm.mutex);
        if (err)
                return err;

        memset(node, 0, sizeof(*node));
        err = drm_mm_insert_node_in_range(&ggtt->vm.mm, node,
                                          size, 0, I915_COLOR_UNEVICTABLE,
                                          0, ggtt->mappable_end,
                                          DRM_MM_INSERT_LOW);

        mutex_unlock(&ggtt->vm.mutex);

        return err;
}

static void
remove_mappable_node(struct i915_ggtt *ggtt, struct drm_mm_node *node)
{
        mutex_lock(&ggtt->vm.mutex);
        drm_mm_remove_node(node);
        mutex_unlock(&ggtt->vm.mutex);
}

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

        if (mutex_lock_interruptible(&ggtt->vm.mutex))
                return -EINTR;

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

        mutex_unlock(&ggtt->vm.mutex);

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

        return 0;
}

int i915_gem_object_unbind(struct drm_i915_gem_object *obj,
                           unsigned long flags)
{
        struct intel_runtime_pm *rpm = &to_i915(obj->base.dev)->runtime_pm;
        LIST_HEAD(still_in_list);
        intel_wakeref_t wakeref;
        struct i915_vma *vma;
        int ret;

        if (list_empty(&obj->vma.list))
                return 0;

        /*
         * As some machines use ACPI to handle runtime-resume callbacks, and
         * ACPI is quite kmalloc happy, we cannot resume beneath the vm->mutex
         * as they are required by the shrinker. Ergo, we wake the device up
         * first just in case.
         */
        wakeref = intel_runtime_pm_get(rpm);

try_again:
        ret = 0;
        spin_lock(&obj->vma.lock);
        while (!ret && (vma = list_first_entry_or_null(&obj->vma.list,
                                                       struct i915_vma,
                                                       obj_link))) {
                struct i915_address_space *vm = vma->vm;

                list_move_tail(&vma->obj_link, &still_in_list);
                if (!i915_vma_is_bound(vma, I915_VMA_BIND_MASK))
                        continue;

                if (flags & I915_GEM_OBJECT_UNBIND_TEST) {
                        ret = -EBUSY;
                        break;
                }

                ret = -EAGAIN;
                if (!i915_vm_tryopen(vm))
                        break;

                /* Prevent vma being freed by i915_vma_parked as we unbind */
                vma = __i915_vma_get(vma);
                spin_unlock(&obj->vma.lock);

                if (vma) {
                        ret = -EBUSY;
                        if (flags & I915_GEM_OBJECT_UNBIND_ACTIVE ||
                            !i915_vma_is_active(vma))
                                ret = i915_vma_unbind(vma);

                        __i915_vma_put(vma);
                }

                i915_vm_close(vm);
                spin_lock(&obj->vma.lock);
        }
        list_splice_init(&still_in_list, &obj->vma.list);
        spin_unlock(&obj->vma.lock);

        if (ret == -EAGAIN && flags & I915_GEM_OBJECT_UNBIND_BARRIER) {
                rcu_barrier(); /* flush the i915_vm_release() */
                goto try_again;
        }

        intel_runtime_pm_put(rpm, wakeref);

        return ret;
}

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

        GEM_BUG_ON(!is_power_of_2(mr->min_page_size));
        size = round_up(*size_p, mr->min_page_size);
        if (size == 0)
                return -EINVAL;

        /* For most of the ABI (e.g. mmap) we think in system pages */
        GEM_BUG_ON(!IS_ALIGNED(size, PAGE_SIZE));

        /* Allocate the new object */
        obj = i915_gem_object_create_region(mr, size, 0);
        if (IS_ERR(obj))
                return PTR_ERR(obj);

        ret = drm_gem_handle_create(file, &obj->base, &handle);
        /* drop reference from allocate - handle holds it now */
        i915_gem_object_put(obj);
        if (ret)
                return ret;

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

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

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

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

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

        if (args->pitch < args->width)
                return -EINVAL;

        args->size = mul_u32_u32(args->pitch, args->height);

        mem_type = INTEL_MEMORY_SYSTEM;
        if (HAS_LMEM(to_i915(dev)))
                mem_type = INTEL_MEMORY_LOCAL;

        return i915_gem_create(file,
                               intel_memory_region_by_type(to_i915(dev),
                                                           mem_type),
                               &args->size, &args->handle);
}

/**
 * Creates a new mm object and returns a handle to it.
 * @dev: drm device pointer
 * @data: ioctl data blob
 * @file: drm file pointer
 */
int
i915_gem_create_ioctl(struct drm_device *dev, void *data,
                      struct drm_file *file)
{
        struct drm_i915_private *i915 = to_i915(dev);
        struct drm_i915_gem_create *args = data;

        i915_gem_flush_free_objects(i915);

        return i915_gem_create(file,
                               intel_memory_region_by_type(i915,
                                                           INTEL_MEMORY_SYSTEM),
                               &args->size, &args->handle);
}

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

        vaddr = kmap(page);

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

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

        kunmap(page);

        return ret ? -EFAULT : 0;
}

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

        ret = i915_gem_object_lock_interruptible(obj, NULL);
        if (ret)
                return ret;

        ret = i915_gem_object_prepare_read(obj, &needs_clflush);
        if (ret) {
                i915_gem_object_unlock(obj);
                return ret;
        }

        fence = i915_gem_object_lock_fence(obj);
        i915_gem_object_finish_access(obj);
        i915_gem_object_unlock(obj);

        if (!fence)
                return -ENOMEM;

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

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

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

        i915_gem_object_unlock_fence(obj, fence);
        return ret;
}

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

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

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

        wakeref = intel_runtime_pm_get(&i915->runtime_pm);
        vma = ERR_PTR(-ENODEV);
        if (!i915_gem_object_is_tiled(obj))
                vma = i915_gem_object_ggtt_pin(obj, NULL, 0, 0,
                                               PIN_MAPPABLE |
                                               PIN_NONBLOCK /* NOWARN */ |
                                               PIN_NOEVICT);
        if (!IS_ERR(vma)) {
                node.start = i915_ggtt_offset(vma);
                node.flags = 0;
        } else {
                ret = insert_mappable_node(ggtt, &node, PAGE_SIZE);
                if (ret)
                        goto out_rpm;
                GEM_BUG_ON(!drm_mm_node_allocated(&node));
        }

        ret = i915_gem_object_lock_interruptible(obj, NULL);
        if (ret)
                goto out_unpin;

        ret = i915_gem_object_set_to_gtt_domain(obj, false);
        if (ret) {
                i915_gem_object_unlock(obj);
                goto out_unpin;
        }

        fence = i915_gem_object_lock_fence(obj);
        i915_gem_object_unlock(obj);
        if (!fence) {
                ret = -ENOMEM;
                goto out_unpin;
        }

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

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

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

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

        i915_gem_object_unlock_fence(obj, fence);
out_unpin:
        if (drm_mm_node_allocated(&node)) {
                ggtt->vm.clear_range(&ggtt->vm, node.start, node.size);
                remove_mappable_node(ggtt, &node);
        } else {
                i915_vma_unpin(vma);
        }
out_rpm:
        intel_runtime_pm_put(&i915->runtime_pm, wakeref);
        return ret;
}

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

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

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

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

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

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

        ret = -ENODEV;
        if (obj->ops->pread)
                ret = obj->ops->pread(obj, args);
        if (ret != -ENODEV)
                goto out;

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

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

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

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

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

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

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

        return unwritten;
}

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

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

        vma = ERR_PTR(-ENODEV);
        if (!i915_gem_object_is_tiled(obj))
                vma = i915_gem_object_ggtt_pin(obj, NULL, 0, 0,
                                               PIN_MAPPABLE |
                                               PIN_NONBLOCK /* NOWARN */ |
                                               PIN_NOEVICT);
        if (!IS_ERR(vma)) {
                node.start = i915_ggtt_offset(vma);
                node.flags = 0;
        } else {
                ret = insert_mappable_node(ggtt, &node, PAGE_SIZE);
                if (ret)
                        goto out_rpm;
                GEM_BUG_ON(!drm_mm_node_allocated(&node));
        }

        ret = i915_gem_object_lock_interruptible(obj, NULL);
        if (ret)
                goto out_unpin;

        ret = i915_gem_object_set_to_gtt_domain(obj, true);
        if (ret) {
                i915_gem_object_unlock(obj);
                goto out_unpin;
        }

        fence = i915_gem_object_lock_fence(obj);
        i915_gem_object_unlock(obj);
        if (!fence) {
                ret = -ENOMEM;
                goto out_unpin;
        }

        i915_gem_object_invalidate_frontbuffer(obj, ORIGIN_CPU);

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

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

        intel_gt_flush_ggtt_writes(ggtt->vm.gt);
        i915_gem_object_flush_frontbuffer(obj, ORIGIN_CPU);

        i915_gem_object_unlock_fence(obj, fence);
out_unpin:
        if (drm_mm_node_allocated(&node)) {
                ggtt->vm.clear_range(&ggtt->vm, node.start, node.size);
                remove_mappable_node(ggtt, &node);
        } else {
                i915_vma_unpin(vma);
        }
out_rpm:
        intel_runtime_pm_put(rpm, wakeref);
        return ret;
}

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

        vaddr = kmap(page);

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

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

        kunmap(page);

        return ret ? -EFAULT : 0;
}

static int
i915_gem_shmem_pwrite(struct drm_i915_gem_object *obj,
                      const struct drm_i915_gem_pwrite *args)
{
        unsigned int partial_cacheline_write;
        unsigned int needs_clflush;
        unsigned int offset, idx;
        struct dma_fence *fence;
        void __user *user_data;
        u64 remain;
        int ret;

        ret = i915_gem_object_lock_interruptible(obj, NULL);
        if (ret)
                return ret;

        ret = i915_gem_object_prepare_write(obj, &needs_clflush);
        if (ret) {
                i915_gem_object_unlock(obj);
                return ret;
        }

        fence = i915_gem_object_lock_fence(obj);
        i915_gem_object_finish_access(obj);
        i915_gem_object_unlock(obj);

        if (!fence)
                return -ENOMEM;

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

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

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

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

        i915_gem_object_flush_frontbuffer(obj, ORIGIN_CPU);
        i915_gem_object_unlock_fence(obj, fence);

        return ret;
}

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

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

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

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

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

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

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

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

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

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

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

        if (ret == -EFAULT || ret == -ENOSPC) {
                if (i915_gem_object_has_struct_page(obj))
                        ret = i915_gem_shmem_pwrite(obj, args);
        }

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

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

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

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

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

        return 0;
}

void i915_gem_runtime_suspend(struct drm_i915_private *i915)
{
        struct drm_i915_gem_object *obj, *on;
        int i;

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

        list_for_each_entry_safe(obj, on,
                                 &i915->ggtt.userfault_list, userfault_link)
                __i915_gem_object_release_mmap_gtt(obj);

        /*
         * The fence will be lost when the device powers down. If any were
         * in use by hardware (i.e. they are pinned), we should not be powering
         * down! All other fences will be reacquired by the user upon waking.
         */
        for (i = 0; i < i915->ggtt.num_fences; i++) {
                struct i915_fence_reg *reg = &i915->ggtt.fence_regs[i];

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

                if (!reg->vma)
                        continue;

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

static void discard_ggtt_vma(struct i915_vma *vma)
{
        struct drm_i915_gem_object *obj = vma->obj;

        spin_lock(&obj->vma.lock);
        if (!RB_EMPTY_NODE(&vma->obj_node)) {
                rb_erase(&vma->obj_node, &obj->vma.tree);
                RB_CLEAR_NODE(&vma->obj_node);
        }
        spin_unlock(&obj->vma.lock);
}

struct i915_vma *
i915_gem_object_ggtt_pin_ww(struct drm_i915_gem_object *obj,
                            struct i915_gem_ww_ctx *ww,
                            const struct i915_ggtt_view *view,
                            u64 size, u64 alignment, u64 flags)
{
        struct drm_i915_private *i915 = to_i915(obj->base.dev);
        struct i915_ggtt *ggtt = &i915->ggtt;
        struct i915_vma *vma;
        int ret;

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

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

new_vma:
        vma = i915_vma_instance(obj, &ggtt->vm, view);
        if (IS_ERR(vma))
                return vma;

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

                        if (flags & PIN_MAPPABLE &&
                            vma->fence_size > ggtt->mappable_end / 2)

                                return ERR_PTR(-ENOSPC);
                }

                if (i915_vma_is_pinned(vma) || i915_vma_is_active(vma)) {
                        discard_ggtt_vma(vma);
                        goto new_vma;
                }

                ret = i915_vma_unbind(vma);
                if (ret)
                        return ERR_PTR(ret);
        }

        ret = i915_vma_pin_ww(vma, ww, size, alignment, flags | PIN_GLOBAL);
        if (ret)
                return ERR_PTR(ret);

        if (vma->fence && !i915_gem_object_is_tiled(obj)) {
                mutex_lock(&ggtt->vm.mutex);
                i915_vma_revoke_fence(vma);
                mutex_unlock(&ggtt->vm.mutex);
        }

        ret = i915_vma_wait_for_bind(vma);
        if (ret) {
                i915_vma_unpin(vma);
                return ERR_PTR(ret);
        }

        return vma;
}

int
i915_gem_madvise_ioctl(struct drm_device *dev, void *data,
                       struct drm_file *file_priv)
{
        struct drm_i915_private *i915 = to_i915(dev);
        struct drm_i915_gem_madvise *args = data;
        struct drm_i915_gem_object *obj;
        int err;

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

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

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

        if (i915_gem_object_has_pages(obj) &&
            i915_gem_object_is_tiled(obj) &&
            i915->quirks & QUIRK_PIN_SWIZZLED_PAGES) {
                if (obj->mm.madv == I915_MADV_WILLNEED) {
                        GEM_BUG_ON(!obj->mm.quirked);
                        __i915_gem_object_unpin_pages(obj);
                        obj->mm.quirked = false;
                }
                if (args->madv == I915_MADV_WILLNEED) {
                        GEM_BUG_ON(obj->mm.quirked);
                        __i915_gem_object_pin_pages(obj);
                        obj->mm.quirked = true;
                }
        }

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

        if (i915_gem_object_has_pages(obj)) {
                struct list_head *list;

                if (i915_gem_object_is_shrinkable(obj)) {
                        unsigned long flags;

                        spin_lock_irqsave(&i915->mm.obj_lock, flags);

                        if (obj->mm.madv != I915_MADV_WILLNEED)
                                list = &i915->mm.purge_list;
                        else
                                list = &i915->mm.shrink_list;
                        list_move_tail(&obj->mm.link, list);

                        spin_unlock_irqrestore(&i915->mm.obj_lock, flags);
                }
        }

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

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

out:
        i915_gem_object_put(obj);
        return err;
}

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

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

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

        intel_uc_fetch_firmwares(&dev_priv->gt.uc);
        intel_wopcm_init(&dev_priv->wopcm);

        ret = i915_init_ggtt(dev_priv);
        if (ret) {
                GEM_BUG_ON(ret == -EIO);
                goto err_unlock;
        }

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

        ret = intel_gt_init(&dev_priv->gt);
        if (ret)
                goto err_unlock;

        return 0;

        /*
         * Unwinding is complicated by that we want to handle -EIO to mean
         * disable GPU submission but keep KMS alive. We want to mark the
         * HW as irrevisibly wedged, but keep enough state around that the
         * driver doesn't explode during runtime.
         */
err_unlock:
        i915_gem_drain_workqueue(dev_priv);

        if (ret != -EIO) {
                intel_uc_cleanup_firmwares(&dev_priv->gt.uc);
                i915_gem_cleanup_userptr(dev_priv);
        }

        if (ret == -EIO) {
                /*
                 * Allow engines or uC initialisation to fail by marking the GPU
                 * as wedged. But we only want to do this when the GPU is angry,
                 * for all other failure, such as an allocation failure, bail.
                 */
                if (!intel_gt_is_wedged(&dev_priv->gt)) {
                        i915_probe_error(dev_priv,
                                         "Failed to initialize GPU, declaring it wedged!\n");
                        intel_gt_set_wedged(&dev_priv->gt);
                }

                /* Minimal basic recovery for KMS */
                ret = i915_ggtt_enable_hw(dev_priv);
                i915_ggtt_resume(&dev_priv->ggtt);
                intel_init_clock_gating(dev_priv);
        }

        i915_gem_drain_freed_objects(dev_priv);
        return ret;
}

void i915_gem_driver_register(struct drm_i915_private *i915)
{
        i915_gem_driver_register__shrinker(i915);

        intel_engines_driver_register(i915);
}

void i915_gem_driver_unregister(struct drm_i915_private *i915)
{
        i915_gem_driver_unregister__shrinker(i915);
}

void i915_gem_driver_remove(struct drm_i915_private *dev_priv)
{
        intel_wakeref_auto_fini(&dev_priv->ggtt.userfault_wakeref);

        i915_gem_suspend_late(dev_priv);
        intel_gt_driver_remove(&dev_priv->gt);
        dev_priv->uabi_engines = RB_ROOT;

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

        i915_gem_drain_freed_objects(dev_priv);
}

void i915_gem_driver_release(struct drm_i915_private *dev_priv)
{
        i915_gem_driver_release__contexts(dev_priv);

        intel_gt_driver_release(&dev_priv->gt);

        intel_wa_list_free(&dev_priv->gt_wa_list);

        intel_uc_cleanup_firmwares(&dev_priv->gt.uc);
        i915_gem_cleanup_userptr(dev_priv);

        i915_gem_drain_freed_objects(dev_priv);

        drm_WARN_ON(&dev_priv->drm, !list_empty(&dev_priv->gem.contexts.list));
}

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

        init_llist_head(&i915->mm.free_list);

        INIT_LIST_HEAD(&i915->mm.purge_list);
        INIT_LIST_HEAD(&i915->mm.shrink_list);

        i915_gem_init__objects(i915);
}

void i915_gem_init_early(struct drm_i915_private *dev_priv)
{
        i915_gem_init__mm(dev_priv);
        i915_gem_init__contexts(dev_priv);

        spin_lock_init(&dev_priv->fb_tracking.lock);
}

void i915_gem_cleanup_early(struct drm_i915_private *dev_priv)
{
        i915_gem_drain_freed_objects(dev_priv);
        GEM_BUG_ON(!llist_empty(&dev_priv->mm.free_list));
        GEM_BUG_ON(atomic_read(&dev_priv->mm.free_count));
        drm_WARN_ON(&dev_priv->drm, dev_priv->mm.shrink_count);
}

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

        return 0;
}

int i915_gem_freeze_late(struct drm_i915_private *i915)
{
        struct drm_i915_gem_object *obj;
        intel_wakeref_t wakeref;

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

        wakeref = intel_runtime_pm_get(&i915->runtime_pm);

        i915_gem_shrink(i915, -1UL, NULL, ~0);
        i915_gem_drain_freed_objects(i915);

        list_for_each_entry(obj, &i915->mm.shrink_list, mm.link) {
                i915_gem_object_lock(obj, NULL);
                drm_WARN_ON(&i915->drm,
                            i915_gem_object_set_to_cpu_domain(obj, true));
                i915_gem_object_unlock(obj);
        }

        intel_runtime_pm_put(&i915->runtime_pm, wakeref);

        return 0;
}

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

        DRM_DEBUG("\n");

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

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

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

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

        return ret;
}

void i915_gem_ww_ctx_init(struct i915_gem_ww_ctx *ww, bool intr)
{
        ww_acquire_init(&ww->ctx, &reservation_ww_class);
        INIT_LIST_HEAD(&ww->obj_list);
        ww->intr = intr;
        ww->contended = NULL;
}

static void i915_gem_ww_ctx_unlock_all(struct i915_gem_ww_ctx *ww)
{
        struct drm_i915_gem_object *obj;

        while ((obj = list_first_entry_or_null(&ww->obj_list, struct drm_i915_gem_object, obj_link))) {
                list_del(&obj->obj_link);
                i915_gem_object_unlock(obj);
        }
}

void i915_gem_ww_unlock_single(struct drm_i915_gem_object *obj)
{
        list_del(&obj->obj_link);
        i915_gem_object_unlock(obj);
}

void i915_gem_ww_ctx_fini(struct i915_gem_ww_ctx *ww)
{
        i915_gem_ww_ctx_unlock_all(ww);
        WARN_ON(ww->contended);
        ww_acquire_fini(&ww->ctx);
}

int __must_check i915_gem_ww_ctx_backoff(struct i915_gem_ww_ctx *ww)
{
        int ret = 0;

        if (WARN_ON(!ww->contended))
                return -EINVAL;

        i915_gem_ww_ctx_unlock_all(ww);
        if (ww->intr)
                ret = dma_resv_lock_slow_interruptible(ww->contended->base.resv, &ww->ctx);
        else
                dma_resv_lock_slow(ww->contended->base.resv, &ww->ctx);

        if (!ret)
                list_add_tail(&ww->contended->obj_link, &ww->obj_list);

        ww->contended = NULL;

        return ret;
}

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