[linux-2.6-block.git] / drivers / gpu / drm / i915 / gem / i915_gem_object_types.h

/*
 * SPDX-License-Identifier: MIT
 *
 * Copyright © 2016 Intel Corporation
 */

#ifndef __I915_GEM_OBJECT_TYPES_H__
#define __I915_GEM_OBJECT_TYPES_H__

#include <linux/mmu_notifier.h>

#include <drm/drm_gem.h>
#include <drm/ttm/ttm_bo_api.h>
#include <uapi/drm/i915_drm.h>

#include "i915_active.h"
#include "i915_selftest.h"

struct drm_i915_gem_object;
struct intel_fronbuffer;
struct intel_memory_region;

/*
 * struct i915_lut_handle tracks the fast lookups from handle to vma used
 * for execbuf. Although we use a radixtree for that mapping, in order to
 * remove them as the object or context is closed, we need a secondary list
 * and a translation entry (i915_lut_handle).
 */
struct i915_lut_handle {
        struct list_head obj_link;
        struct i915_gem_context *ctx;
        u32 handle;
};

struct drm_i915_gem_object_ops {
        unsigned int flags;
#define I915_GEM_OBJECT_IS_SHRINKABLE                   BIT(1)
/* Skip the shrinker management in set_pages/unset_pages */
#define I915_GEM_OBJECT_SELF_MANAGED_SHRINK_LIST        BIT(2)
#define I915_GEM_OBJECT_IS_PROXY                        BIT(3)
#define I915_GEM_OBJECT_NO_MMAP                         BIT(4)

        /* Interface between the GEM object and its backing storage.
         * get_pages() is called once prior to the use of the associated set
         * of pages before to binding them into the GTT, and put_pages() is
         * called after we no longer need them. As we expect there to be
         * associated cost with migrating pages between the backing storage
         * and making them available for the GPU (e.g. clflush), we may hold
         * onto the pages after they are no longer referenced by the GPU
         * in case they may be used again shortly (for example migrating the
         * pages to a different memory domain within the GTT). put_pages()
         * will therefore most likely be called when the object itself is
         * being released or under memory pressure (where we attempt to
         * reap pages for the shrinker).
         */
        int (*get_pages)(struct drm_i915_gem_object *obj);
        void (*put_pages)(struct drm_i915_gem_object *obj,
                          struct sg_table *pages);
        int (*truncate)(struct drm_i915_gem_object *obj);
        void (*writeback)(struct drm_i915_gem_object *obj);
        int (*shrinker_release_pages)(struct drm_i915_gem_object *obj,
                                      bool no_gpu_wait,
                                      bool should_writeback);

        int (*pread)(struct drm_i915_gem_object *obj,
                     const struct drm_i915_gem_pread *arg);
        int (*pwrite)(struct drm_i915_gem_object *obj,
                      const struct drm_i915_gem_pwrite *arg);
        u64 (*mmap_offset)(struct drm_i915_gem_object *obj);
        void (*unmap_virtual)(struct drm_i915_gem_object *obj);

        int (*dmabuf_export)(struct drm_i915_gem_object *obj);

        /**
         * adjust_lru - notify that the madvise value was updated
         * @obj: The gem object
         *
         * The madvise value may have been updated, or object was recently
         * referenced so act accordingly (Perhaps changing an LRU list etc).
         */
        void (*adjust_lru)(struct drm_i915_gem_object *obj);

        /**
         * delayed_free - Override the default delayed free implementation
         */
        void (*delayed_free)(struct drm_i915_gem_object *obj);

        /**
         * migrate - Migrate object to a different region either for
         * pinning or for as long as the object lock is held.
         */
        int (*migrate)(struct drm_i915_gem_object *obj,
                       struct intel_memory_region *mr);

        void (*release)(struct drm_i915_gem_object *obj);

        const struct vm_operations_struct *mmap_ops;
        const char *name; /* friendly name for debug, e.g. lockdep classes */
};

/**
 * enum i915_cache_level - The supported GTT caching values for system memory
 * pages.
 *
 * These translate to some special GTT PTE bits when binding pages into some
 * address space. It also determines whether an object, or rather its pages are
 * coherent with the GPU, when also reading or writing through the CPU cache
 * with those pages.
 *
 * Userspace can also control this through struct drm_i915_gem_caching.
 */
enum i915_cache_level {
        /**
         * @I915_CACHE_NONE:
         *
         * GPU access is not coherent with the CPU cache. If the cache is dirty
         * and we need the underlying pages to be coherent with some later GPU
         * access then we need to manually flush the pages.
         *
         * On shared LLC platforms reads and writes through the CPU cache are
         * still coherent even with this setting. See also
         * &drm_i915_gem_object.cache_coherent for more details. Due to this we
         * should only ever use uncached for scanout surfaces, otherwise we end
         * up over-flushing in some places.
         *
         * This is the default on non-LLC platforms.
         */
        I915_CACHE_NONE = 0,
        /**
         * @I915_CACHE_LLC:
         *
         * GPU access is coherent with the CPU cache. If the cache is dirty,
         * then the GPU will ensure that access remains coherent, when both
         * reading and writing through the CPU cache. GPU writes can dirty the
         * CPU cache.
         *
         * Not used for scanout surfaces.
         *
         * Applies to both platforms with shared LLC(HAS_LLC), and snooping
         * based platforms(HAS_SNOOP).
         *
         * This is the default on shared LLC platforms.  The only exception is
         * scanout objects, where the display engine is not coherent with the
         * CPU cache. For such objects I915_CACHE_NONE or I915_CACHE_WT is
         * automatically applied by the kernel in pin_for_display, if userspace
         * has not done so already.
         */
        I915_CACHE_LLC,
        /**
         * @I915_CACHE_L3_LLC:
         *
         * Explicitly enable the Gfx L3 cache, with coherent LLC.
         *
         * The Gfx L3 sits between the domain specific caches, e.g
         * sampler/render caches, and the larger LLC. LLC is coherent with the
         * GPU, but L3 is only visible to the GPU, so likely needs to be flushed
         * when the workload completes.
         *
         * Not used for scanout surfaces.
         *
         * Only exposed on some gen7 + GGTT. More recent hardware has dropped
         * this explicit setting, where it should now be enabled by default.
         */
        I915_CACHE_L3_LLC,
        /**
         * @I915_CACHE_WT:
         *
         * Write-through. Used for scanout surfaces.
         *
         * The GPU can utilise the caches, while still having the display engine
         * be coherent with GPU writes, as a result we don't need to flush the
         * CPU caches when moving out of the render domain. This is the default
         * setting chosen by the kernel, if supported by the HW, otherwise we
         * fallback to I915_CACHE_NONE. On the CPU side writes through the CPU
         * cache still need to be flushed, to remain coherent with the display
         * engine.
         */
        I915_CACHE_WT,
};

enum i915_map_type {
        I915_MAP_WB = 0,
        I915_MAP_WC,
#define I915_MAP_OVERRIDE BIT(31)
        I915_MAP_FORCE_WB = I915_MAP_WB | I915_MAP_OVERRIDE,
        I915_MAP_FORCE_WC = I915_MAP_WC | I915_MAP_OVERRIDE,
};

enum i915_mmap_type {
        I915_MMAP_TYPE_GTT = 0,
        I915_MMAP_TYPE_WC,
        I915_MMAP_TYPE_WB,
        I915_MMAP_TYPE_UC,
        I915_MMAP_TYPE_FIXED,
};

struct i915_mmap_offset {
        struct drm_vma_offset_node vma_node;
        struct drm_i915_gem_object *obj;
        enum i915_mmap_type mmap_type;

        struct rb_node offset;
};

struct i915_gem_object_page_iter {
        struct scatterlist *sg_pos;
        unsigned int sg_idx; /* in pages, but 32bit eek! */

        struct radix_tree_root radix;
        struct mutex lock; /* protects this cache */
};

struct drm_i915_gem_object {
        /*
         * We might have reason to revisit the below since it wastes
         * a lot of space for non-ttm gem objects.
         * In any case, always use the accessors for the ttm_buffer_object
         * when accessing it.
         */
        union {
                struct drm_gem_object base;
                struct ttm_buffer_object __do_not_access;
        };

        const struct drm_i915_gem_object_ops *ops;

        struct {
                /**
                 * @vma.lock: protect the list/tree of vmas
                 */
                spinlock_t lock;

                /**
                 * @vma.list: List of VMAs backed by this object
                 *
                 * The VMA on this list are ordered by type, all GGTT vma are
                 * placed at the head and all ppGTT vma are placed at the tail.
                 * The different types of GGTT vma are unordered between
                 * themselves, use the @vma.tree (which has a defined order
                 * between all VMA) to quickly find an exact match.
                 */
                struct list_head list;

                /**
                 * @vma.tree: Ordered tree of VMAs backed by this object
                 *
                 * All VMA created for this object are placed in the @vma.tree
                 * for fast retrieval via a binary search in
                 * i915_vma_instance(). They are also added to @vma.list for
                 * easy iteration.
                 */
                struct rb_root tree;
        } vma;

        /**
         * @lut_list: List of vma lookup entries in use for this object.
         *
         * If this object is closed, we need to remove all of its VMA from
         * the fast lookup index in associated contexts; @lut_list provides
         * this translation from object to context->handles_vma.
         */
        struct list_head lut_list;
        spinlock_t lut_lock; /* guards lut_list */

        /**
         * @obj_link: Link into @i915_gem_ww_ctx.obj_list
         *
         * When we lock this object through i915_gem_object_lock() with a
         * context, we add it to the list to ensure we can unlock everything
         * when i915_gem_ww_ctx_backoff() or i915_gem_ww_ctx_fini() are called.
         */
        struct list_head obj_link;
        /**
         * @shared_resv_from: The object shares the resv from this vm.
         */
        struct i915_address_space *shares_resv_from;

        union {
                struct rcu_head rcu;
                struct llist_node freed;
        };

        /**
         * Whether the object is currently in the GGTT mmap.
         */
        unsigned int userfault_count;
        struct list_head userfault_link;

        struct {
                spinlock_t lock; /* Protects access to mmo offsets */
                struct rb_root offsets;
        } mmo;

        I915_SELFTEST_DECLARE(struct list_head st_link);

        unsigned long flags;
#define I915_BO_ALLOC_CONTIGUOUS  BIT(0)
#define I915_BO_ALLOC_VOLATILE    BIT(1)
#define I915_BO_ALLOC_CPU_CLEAR   BIT(2)
#define I915_BO_ALLOC_USER        BIT(3)
/* Object is allowed to lose its contents on suspend / resume, even if pinned */
#define I915_BO_ALLOC_PM_VOLATILE BIT(4)
/* Object needs to be restored early using memcpy during resume */
#define I915_BO_ALLOC_PM_EARLY    BIT(5)
#define I915_BO_ALLOC_FLAGS (I915_BO_ALLOC_CONTIGUOUS | \
                             I915_BO_ALLOC_VOLATILE | \
                             I915_BO_ALLOC_CPU_CLEAR | \
                             I915_BO_ALLOC_USER | \
                             I915_BO_ALLOC_PM_VOLATILE | \
                             I915_BO_ALLOC_PM_EARLY)
#define I915_BO_READONLY          BIT(6)
#define I915_TILING_QUIRK_BIT     7 /* unknown swizzling; do not release! */
#define I915_BO_PROTECTED         BIT(8)
#define I915_BO_WAS_BOUND_BIT     9
        /**
         * @mem_flags - Mutable placement-related flags
         *
         * These are flags that indicate specifics of the memory region
         * the object is currently in. As such they are only stable
         * either under the object lock or if the object is pinned.
         */
        unsigned int mem_flags;
#define I915_BO_FLAG_STRUCT_PAGE BIT(0) /* Object backed by struct pages */
#define I915_BO_FLAG_IOMEM       BIT(1) /* Object backed by IO memory */
        /**
         * @cache_level: The desired GTT caching level.
         *
         * See enum i915_cache_level for possible values, along with what
         * each does.
         */
        unsigned int cache_level:3;
        /**
         * @cache_coherent:
         *
         * Track whether the pages are coherent with the GPU if reading or
         * writing through the CPU caches. The largely depends on the
         * @cache_level setting.
         *
         * On platforms which don't have the shared LLC(HAS_SNOOP), like on Atom
         * platforms, coherency must be explicitly requested with some special
         * GTT caching bits(see enum i915_cache_level). When enabling coherency
         * it does come at a performance and power cost on such platforms. On
         * the flip side the kernel does not need to manually flush any buffers
         * which need to be coherent with the GPU, if the object is not coherent
         * i.e @cache_coherent is zero.
         *
         * On platforms that share the LLC with the CPU(HAS_LLC), all GT memory
         * access will automatically snoop the CPU caches(even with CACHE_NONE).
         * The one exception is when dealing with the display engine, like with
         * scanout surfaces. To handle this the kernel will always flush the
         * surface out of the CPU caches when preparing it for scanout.  Also
         * note that since scanout surfaces are only ever read by the display
         * engine we only need to care about flushing any writes through the CPU
         * cache, reads on the other hand will always be coherent.
         *
         * Something strange here is why @cache_coherent is not a simple
         * boolean, i.e coherent vs non-coherent. The reasoning for this is back
         * to the display engine not being fully coherent. As a result scanout
         * surfaces will either be marked as I915_CACHE_NONE or I915_CACHE_WT.
         * In the case of seeing I915_CACHE_NONE the kernel makes the assumption
         * that this is likely a scanout surface, and will set @cache_coherent
         * as only I915_BO_CACHE_COHERENT_FOR_READ, on platforms with the shared
         * LLC. The kernel uses this to always flush writes through the CPU
         * cache as early as possible, where it can, in effect keeping
         * @cache_dirty clean, so we can potentially avoid stalling when
         * flushing the surface just before doing the scanout.  This does mean
         * we might unnecessarily flush non-scanout objects in some places, but
         * the default assumption is that all normal objects should be using
         * I915_CACHE_LLC, at least on platforms with the shared LLC.
         *
         * Supported values:
         *
         * I915_BO_CACHE_COHERENT_FOR_READ:
         *
         * On shared LLC platforms, we use this for special scanout surfaces,
         * where the display engine is not coherent with the CPU cache. As such
         * we need to ensure we flush any writes before doing the scanout. As an
         * optimisation we try to flush any writes as early as possible to avoid
         * stalling later.
         *
         * Thus for scanout surfaces using I915_CACHE_NONE, on shared LLC
         * platforms, we use:
         *
         *      cache_coherent = I915_BO_CACHE_COHERENT_FOR_READ
         *
         * While for normal objects that are fully coherent, including special
         * scanout surfaces marked as I915_CACHE_WT, we use:
         *
         *      cache_coherent = I915_BO_CACHE_COHERENT_FOR_READ |
         *                       I915_BO_CACHE_COHERENT_FOR_WRITE
         *
         * And then for objects that are not coherent at all we use:
         *
         *      cache_coherent = 0
         *
         * I915_BO_CACHE_COHERENT_FOR_WRITE:
         *
         * When writing through the CPU cache, the GPU is still coherent. Note
         * that this also implies I915_BO_CACHE_COHERENT_FOR_READ.
         */
#define I915_BO_CACHE_COHERENT_FOR_READ BIT(0)
#define I915_BO_CACHE_COHERENT_FOR_WRITE BIT(1)
        unsigned int cache_coherent:2;

        /**
         * @cache_dirty:
         *
         * Track if we are we dirty with writes through the CPU cache for this
         * object. As a result reading directly from main memory might yield
         * stale data.
         *
         * This also ties into whether the kernel is tracking the object as
         * coherent with the GPU, as per @cache_coherent, as it determines if
         * flushing might be needed at various points.
         *
         * Another part of @cache_dirty is managing flushing when first
         * acquiring the pages for system memory, at this point the pages are
         * considered foreign, so the default assumption is that the cache is
         * dirty, for example the page zeroing done by the kernel might leave
         * writes though the CPU cache, or swapping-in, while the actual data in
         * main memory is potentially stale.  Note that this is a potential
         * security issue when dealing with userspace objects and zeroing. Now,
         * whether we actually need apply the big sledgehammer of flushing all
         * the pages on acquire depends on if @cache_coherent is marked as
         * I915_BO_CACHE_COHERENT_FOR_WRITE, i.e that the GPU will be coherent
         * for both reads and writes though the CPU cache.
         *
         * Note that on shared LLC platforms we still apply the heavy flush for
         * I915_CACHE_NONE objects, under the assumption that this is going to
         * be used for scanout.
         *
         * Update: On some hardware there is now also the 'Bypass LLC' MOCS
         * entry, which defeats our @cache_coherent tracking, since userspace
         * can freely bypass the CPU cache when touching the pages with the GPU,
         * where the kernel is completely unaware. On such platform we need
         * apply the sledgehammer-on-acquire regardless of the @cache_coherent.
         *
         * Special care is taken on non-LLC platforms, to prevent potential
         * information leak. The driver currently ensures:
         *
         *   1. All userspace objects, by default, have @cache_level set as
         *   I915_CACHE_NONE. The only exception is userptr objects, where we
         *   instead force I915_CACHE_LLC, but we also don't allow userspace to
         *   ever change the @cache_level for such objects. Another special case
         *   is dma-buf, which doesn't rely on @cache_dirty,  but there we
         *   always do a forced flush when acquiring the pages, if there is a
         *   chance that the pages can be read directly from main memory with
         *   the GPU.
         *
         *   2. All I915_CACHE_NONE objects have @cache_dirty initially true.
         *
         *   3. All swapped-out objects(i.e shmem) have @cache_dirty set to
         *   true.
         *
         *   4. The @cache_dirty is never freely reset before the initial
         *   flush, even if userspace adjusts the @cache_level through the
         *   i915_gem_set_caching_ioctl.
         *
         *   5. All @cache_dirty objects(including swapped-in) are initially
         *   flushed with a synchronous call to drm_clflush_sg in
         *   __i915_gem_object_set_pages. The @cache_dirty can be freely reset
         *   at this point. All further asynchronous clfushes are never security
         *   critical, i.e userspace is free to race against itself.
         */
        unsigned int cache_dirty:1;

        /**
         * @read_domains: Read memory domains.
         *
         * These monitor which caches contain read/write data related to the
         * object. When transitioning from one set of domains to another,
         * the driver is called to ensure that caches are suitably flushed and
         * invalidated.
         */
        u16 read_domains;

        /**
         * @write_domain: Corresponding unique write memory domain.
         */
        u16 write_domain;

        struct intel_frontbuffer __rcu *frontbuffer;

        /** Current tiling stride for the object, if it's tiled. */
        unsigned int tiling_and_stride;
#define FENCE_MINIMUM_STRIDE 128 /* See i915_tiling_ok() */
#define TILING_MASK (FENCE_MINIMUM_STRIDE - 1)
#define STRIDE_MASK (~TILING_MASK)

        struct {
                /*
                 * Protects the pages and their use. Do not use directly, but
                 * instead go through the pin/unpin interfaces.
                 */
                atomic_t pages_pin_count;

                /**
                 * @shrink_pin: Prevents the pages from being made visible to
                 * the shrinker, while the shrink_pin is non-zero. Most users
                 * should pretty much never have to care about this, outside of
                 * some special use cases.
                 *
                 * By default most objects will start out as visible to the
                 * shrinker(if I915_GEM_OBJECT_IS_SHRINKABLE) as soon as the
                 * backing pages are attached to the object, like in
                 * __i915_gem_object_set_pages(). They will then be removed the
                 * shrinker list once the pages are released.
                 *
                 * The @shrink_pin is incremented by calling
                 * i915_gem_object_make_unshrinkable(), which will also remove
                 * the object from the shrinker list, if the pin count was zero.
                 *
                 * Callers will then typically call
                 * i915_gem_object_make_shrinkable() or
                 * i915_gem_object_make_purgeable() to decrement the pin count,
                 * and make the pages visible again.
                 */
                atomic_t shrink_pin;

                /**
                 * @ttm_shrinkable: True when the object is using shmem pages
                 * underneath. Protected by the object lock.
                 */
                bool ttm_shrinkable;

                /**
                 * Priority list of potential placements for this object.
                 */
                struct intel_memory_region **placements;
                int n_placements;

                /**
                 * Memory region for this object.
                 */
                struct intel_memory_region *region;

                /**
                 * Memory manager resource allocated for this object. Only
                 * needed for the mock region.
                 */
                struct ttm_resource *res;

                /**
                 * Element within memory_region->objects or region->purgeable
                 * if the object is marked as DONTNEED. Access is protected by
                 * region->obj_lock.
                 */
                struct list_head region_link;

                struct i915_refct_sgt *rsgt;
                struct sg_table *pages;
                void *mapping;

                struct i915_page_sizes {
                        /**
                         * The sg mask of the pages sg_table. i.e the mask of
                         * of the lengths for each sg entry.
                         */
                        unsigned int phys;

                        /**
                         * The gtt page sizes we are allowed to use given the
                         * sg mask and the supported page sizes. This will
                         * express the smallest unit we can use for the whole
                         * object, as well as the larger sizes we may be able
                         * to use opportunistically.
                         */
                        unsigned int sg;

                        /**
                         * The actual gtt page size usage. Since we can have
                         * multiple vma associated with this object we need to
                         * prevent any trampling of state, hence a copy of this
                         * struct also lives in each vma, therefore the gtt
                         * value here should only be read/write through the vma.
                         */
                        unsigned int gtt;
                } page_sizes;

                I915_SELFTEST_DECLARE(unsigned int page_mask);

                struct i915_gem_object_page_iter get_page;
                struct i915_gem_object_page_iter get_dma_page;

                /**
                 * Element within i915->mm.shrink_list or i915->mm.purge_list,
                 * locked by i915->mm.obj_lock.
                 */
                struct list_head link;

                /**
                 * Advice: are the backing pages purgeable?
                 */
                unsigned int madv:2;

                /**
                 * This is set if the object has been written to since the
                 * pages were last acquired.
                 */
                bool dirty:1;
        } mm;

        struct {
                struct i915_refct_sgt *cached_io_rsgt;
                struct i915_gem_object_page_iter get_io_page;
                struct drm_i915_gem_object *backup;
                bool created:1;
        } ttm;

        /*
         * Record which PXP key instance this object was created against (if
         * any), so we can use it to determine if the encryption is valid by
         * comparing against the current key instance.
         */
        u32 pxp_key_instance;

        /** Record of address bit 17 of each page at last unbind. */
        unsigned long *bit_17;

        union {
#ifdef CONFIG_MMU_NOTIFIER
                struct i915_gem_userptr {
                        uintptr_t ptr;
                        unsigned long notifier_seq;

                        struct mmu_interval_notifier notifier;
                        struct page **pvec;
                        int page_ref;
                } userptr;
#endif

                struct drm_mm_node *stolen;

                unsigned long scratch;
                u64 encode;

                void *gvt_info;
        };
};

static inline struct drm_i915_gem_object *
to_intel_bo(struct drm_gem_object *gem)
{
        /* Assert that to_intel_bo(NULL) == NULL */
        BUILD_BUG_ON(offsetof(struct drm_i915_gem_object, base));

        return container_of(gem, struct drm_i915_gem_object, base);
}

#endif