bpf: Prevent memory disambiguation attack

[linux/fpc-iii.git] / drivers / gpu / drm / i915 / i915_vma.h

/*
 * Copyright © 2016 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.
 *
 */

#ifndef __I915_VMA_H__
#define __I915_VMA_H__

#include <linux/io-mapping.h>

#include <drm/drm_mm.h>

#include "i915_gem_gtt.h"
#include "i915_gem_fence_reg.h"
#include "i915_gem_object.h"
#include "i915_gem_request.h"


enum i915_cache_level;

/**
 * A VMA represents a GEM BO that is bound into an address space. Therefore, a
 * VMA's presence cannot be guaranteed before binding, or after unbinding the
 * object into/from the address space.
 *
 * To make things as simple as possible (ie. no refcounting), a VMA's lifetime
 * will always be <= an objects lifetime. So object refcounting should cover us.
 */
struct i915_vma {
        struct drm_mm_node node;
        struct drm_i915_gem_object *obj;
        struct i915_address_space *vm;
        struct drm_i915_fence_reg *fence;
        struct reservation_object *resv; /** Alias of obj->resv */
        struct sg_table *pages;
        void __iomem *iomap;
        u64 size;
        u64 display_alignment;
        struct i915_page_sizes page_sizes;

        u32 fence_size;
        u32 fence_alignment;

        /**
         * Count of the number of times this vma has been opened by different
         * handles (but same file) for execbuf, i.e. the number of aliases
         * that exist in the ctx->handle_vmas LUT for this vma.
         */
        unsigned int open_count;
        unsigned long flags;
        /**
         * How many users have pinned this object in GTT space. The following
         * users can each hold at most one reference: pwrite/pread, execbuffer
         * (objects are not allowed multiple times for the same batchbuffer),
         * and the framebuffer code. When switching/pageflipping, the
         * framebuffer code has at most two buffers pinned per crtc.
         *
         * In the worst case this is 1 + 1 + 1 + 2*2 = 7. That would fit into 3
         * bits with absolutely no headroom. So use 4 bits.
         */
#define I915_VMA_PIN_MASK 0xf
#define I915_VMA_PIN_OVERFLOW   BIT(5)

        /** Flags and address space this VMA is bound to */
#define I915_VMA_GLOBAL_BIND    BIT(6)
#define I915_VMA_LOCAL_BIND     BIT(7)
#define I915_VMA_BIND_MASK (I915_VMA_GLOBAL_BIND | I915_VMA_LOCAL_BIND | I915_VMA_PIN_OVERFLOW)

#define I915_VMA_GGTT           BIT(8)
#define I915_VMA_CAN_FENCE      BIT(9)
#define I915_VMA_CLOSED         BIT(10)
#define I915_VMA_USERFAULT_BIT  11
#define I915_VMA_USERFAULT      BIT(I915_VMA_USERFAULT_BIT)
#define I915_VMA_GGTT_WRITE     BIT(12)

        unsigned int active;
        struct i915_gem_active last_read[I915_NUM_ENGINES];
        struct i915_gem_active last_fence;

        /**
         * Support different GGTT views into the same object.
         * This means there can be multiple VMA mappings per object and per VM.
         * i915_ggtt_view_type is used to distinguish between those entries.
         * The default one of zero (I915_GGTT_VIEW_NORMAL) is default and also
         * assumed in GEM functions which take no ggtt view parameter.
         */
        struct i915_ggtt_view ggtt_view;

        /** This object's place on the active/inactive lists */
        struct list_head vm_link;

        struct list_head obj_link; /* Link in the object's VMA list */
        struct rb_node obj_node;
        struct hlist_node obj_hash;

        /** This vma's place in the execbuf reservation list */
        struct list_head exec_link;
        struct list_head reloc_link;

        /** This vma's place in the eviction list */
        struct list_head evict_link;

        /**
         * Used for performing relocations during execbuffer insertion.
         */
        unsigned int *exec_flags;
        struct hlist_node exec_node;
        u32 exec_handle;
};

struct i915_vma *
i915_vma_instance(struct drm_i915_gem_object *obj,
                  struct i915_address_space *vm,
                  const struct i915_ggtt_view *view);

void i915_vma_unpin_and_release(struct i915_vma **p_vma);

static inline bool i915_vma_is_ggtt(const struct i915_vma *vma)
{
        return vma->flags & I915_VMA_GGTT;
}

static inline bool i915_vma_has_ggtt_write(const struct i915_vma *vma)
{
        return vma->flags & I915_VMA_GGTT_WRITE;
}

static inline void i915_vma_set_ggtt_write(struct i915_vma *vma)
{
        GEM_BUG_ON(!i915_vma_is_ggtt(vma));
        vma->flags |= I915_VMA_GGTT_WRITE;
}

static inline void i915_vma_unset_ggtt_write(struct i915_vma *vma)
{
        vma->flags &= ~I915_VMA_GGTT_WRITE;
}

void i915_vma_flush_writes(struct i915_vma *vma);

static inline bool i915_vma_is_map_and_fenceable(const struct i915_vma *vma)
{
        return vma->flags & I915_VMA_CAN_FENCE;
}

static inline bool i915_vma_is_closed(const struct i915_vma *vma)
{
        return vma->flags & I915_VMA_CLOSED;
}

static inline bool i915_vma_set_userfault(struct i915_vma *vma)
{
        GEM_BUG_ON(!i915_vma_is_map_and_fenceable(vma));
        return __test_and_set_bit(I915_VMA_USERFAULT_BIT, &vma->flags);
}

static inline void i915_vma_unset_userfault(struct i915_vma *vma)
{
        return __clear_bit(I915_VMA_USERFAULT_BIT, &vma->flags);
}

static inline bool i915_vma_has_userfault(const struct i915_vma *vma)
{
        return test_bit(I915_VMA_USERFAULT_BIT, &vma->flags);
}

static inline unsigned int i915_vma_get_active(const struct i915_vma *vma)
{
        return vma->active;
}

static inline bool i915_vma_is_active(const struct i915_vma *vma)
{
        return i915_vma_get_active(vma);
}

static inline void i915_vma_set_active(struct i915_vma *vma,
                                       unsigned int engine)
{
        vma->active |= BIT(engine);
}

static inline void i915_vma_clear_active(struct i915_vma *vma,
                                         unsigned int engine)
{
        vma->active &= ~BIT(engine);
}

static inline bool i915_vma_has_active_engine(const struct i915_vma *vma,
                                              unsigned int engine)
{
        return vma->active & BIT(engine);
}

static inline u32 i915_ggtt_offset(const struct i915_vma *vma)
{
        GEM_BUG_ON(!i915_vma_is_ggtt(vma));
        GEM_BUG_ON(!vma->node.allocated);
        GEM_BUG_ON(upper_32_bits(vma->node.start));
        GEM_BUG_ON(upper_32_bits(vma->node.start + vma->node.size - 1));
        return lower_32_bits(vma->node.start);
}

static inline struct i915_vma *i915_vma_get(struct i915_vma *vma)
{
        i915_gem_object_get(vma->obj);
        return vma;
}

static inline void i915_vma_put(struct i915_vma *vma)
{
        i915_gem_object_put(vma->obj);
}

static __always_inline ptrdiff_t ptrdiff(const void *a, const void *b)
{
        return a - b;
}

static inline long
i915_vma_compare(struct i915_vma *vma,
                 struct i915_address_space *vm,
                 const struct i915_ggtt_view *view)
{
        ptrdiff_t cmp;

        GEM_BUG_ON(view && !i915_is_ggtt(vm));

        cmp = ptrdiff(vma->vm, vm);
        if (cmp)
                return cmp;

        BUILD_BUG_ON(I915_GGTT_VIEW_NORMAL != 0);
        cmp = vma->ggtt_view.type;
        if (!view)
                return cmp;

        cmp -= view->type;
        if (cmp)
                return cmp;

        /* ggtt_view.type also encodes its size so that we both distinguish
         * different views using it as a "type" and also use a compact (no
         * accessing of uninitialised padding bytes) memcmp without storing
         * an extra parameter or adding more code.
         *
         * To ensure that the memcmp is valid for all branches of the union,
         * even though the code looks like it is just comparing one branch,
         * we assert above that all branches have the same address, and that
         * each branch has a unique type/size.
         */
        BUILD_BUG_ON(I915_GGTT_VIEW_NORMAL >= I915_GGTT_VIEW_PARTIAL);
        BUILD_BUG_ON(I915_GGTT_VIEW_PARTIAL >= I915_GGTT_VIEW_ROTATED);
        BUILD_BUG_ON(offsetof(typeof(*view), rotated) !=
                     offsetof(typeof(*view), partial));
        return memcmp(&vma->ggtt_view.partial, &view->partial, view->type);
}

int i915_vma_bind(struct i915_vma *vma, enum i915_cache_level cache_level,
                  u32 flags);
bool i915_gem_valid_gtt_space(struct i915_vma *vma, unsigned long cache_level);
bool i915_vma_misplaced(const struct i915_vma *vma,
                        u64 size, u64 alignment, u64 flags);
void __i915_vma_set_map_and_fenceable(struct i915_vma *vma);
void i915_vma_revoke_mmap(struct i915_vma *vma);
int __must_check i915_vma_unbind(struct i915_vma *vma);
void i915_vma_unlink_ctx(struct i915_vma *vma);
void i915_vma_close(struct i915_vma *vma);

int __i915_vma_do_pin(struct i915_vma *vma,
                      u64 size, u64 alignment, u64 flags);
static inline int __must_check
i915_vma_pin(struct i915_vma *vma, u64 size, u64 alignment, u64 flags)
{
        BUILD_BUG_ON(PIN_MBZ != I915_VMA_PIN_OVERFLOW);
        BUILD_BUG_ON(PIN_GLOBAL != I915_VMA_GLOBAL_BIND);
        BUILD_BUG_ON(PIN_USER != I915_VMA_LOCAL_BIND);

        /* Pin early to prevent the shrinker/eviction logic from destroying
         * our vma as we insert and bind.
         */
        if (likely(((++vma->flags ^ flags) & I915_VMA_BIND_MASK) == 0)) {
                GEM_BUG_ON(!drm_mm_node_allocated(&vma->node));
                GEM_BUG_ON(i915_vma_misplaced(vma, size, alignment, flags));
                return 0;
        }

        return __i915_vma_do_pin(vma, size, alignment, flags);
}

static inline int i915_vma_pin_count(const struct i915_vma *vma)
{
        return vma->flags & I915_VMA_PIN_MASK;
}

static inline bool i915_vma_is_pinned(const struct i915_vma *vma)
{
        return i915_vma_pin_count(vma);
}

static inline void __i915_vma_pin(struct i915_vma *vma)
{
        vma->flags++;
        GEM_BUG_ON(vma->flags & I915_VMA_PIN_OVERFLOW);
}

static inline void __i915_vma_unpin(struct i915_vma *vma)
{
        vma->flags--;
}

static inline void i915_vma_unpin(struct i915_vma *vma)
{
        GEM_BUG_ON(!i915_vma_is_pinned(vma));
        GEM_BUG_ON(!drm_mm_node_allocated(&vma->node));
        __i915_vma_unpin(vma);
}

/**
 * i915_vma_pin_iomap - calls ioremap_wc to map the GGTT VMA via the aperture
 * @vma: VMA to iomap
 *
 * The passed in VMA has to be pinned in the global GTT mappable region.
 * An extra pinning of the VMA is acquired for the return iomapping,
 * the caller must call i915_vma_unpin_iomap to relinquish the pinning
 * after the iomapping is no longer required.
 *
 * Callers must hold the struct_mutex.
 *
 * Returns a valid iomapped pointer or ERR_PTR.
 */
void __iomem *i915_vma_pin_iomap(struct i915_vma *vma);
#define IO_ERR_PTR(x) ((void __iomem *)ERR_PTR(x))

/**
 * i915_vma_unpin_iomap - unpins the mapping returned from i915_vma_iomap
 * @vma: VMA to unpin
 *
 * Unpins the previously iomapped VMA from i915_vma_pin_iomap().
 *
 * Callers must hold the struct_mutex. This function is only valid to be
 * called on a VMA previously iomapped by the caller with i915_vma_pin_iomap().
 */
void i915_vma_unpin_iomap(struct i915_vma *vma);

static inline struct page *i915_vma_first_page(struct i915_vma *vma)
{
        GEM_BUG_ON(!vma->pages);
        return sg_page(vma->pages->sgl);
}

/**
 * i915_vma_pin_fence - pin fencing state
 * @vma: vma to pin fencing for
 *
 * This pins the fencing state (whether tiled or untiled) to make sure the
 * vma (and its object) is ready to be used as a scanout target. Fencing
 * status must be synchronize first by calling i915_vma_get_fence():
 *
 * The resulting fence pin reference must be released again with
 * i915_vma_unpin_fence().
 *
 * Returns:
 *
 * True if the vma has a fence, false otherwise.
 */
int i915_vma_pin_fence(struct i915_vma *vma);
int __must_check i915_vma_put_fence(struct i915_vma *vma);

static inline void __i915_vma_unpin_fence(struct i915_vma *vma)
{
        GEM_BUG_ON(vma->fence->pin_count <= 0);
        vma->fence->pin_count--;
}

/**
 * i915_vma_unpin_fence - unpin fencing state
 * @vma: vma to unpin fencing for
 *
 * This releases the fence pin reference acquired through
 * i915_vma_pin_fence. It will handle both objects with and without an
 * attached fence correctly, callers do not need to distinguish this.
 */
static inline void
i915_vma_unpin_fence(struct i915_vma *vma)
{
        lockdep_assert_held(&vma->obj->base.dev->struct_mutex);
        if (vma->fence)
                __i915_vma_unpin_fence(vma);
}

#define for_each_until(cond) if (cond) break; else

/**
 * for_each_ggtt_vma - Iterate over the GGTT VMA belonging to an object.
 * @V: the #i915_vma iterator
 * @OBJ: the #drm_i915_gem_object
 *
 * GGTT VMA are placed at the being of the object's vma_list, see
 * vma_create(), so we can stop our walk as soon as we see a ppgtt VMA,
 * or the list is empty ofc.
 */
#define for_each_ggtt_vma(V, OBJ) \
        list_for_each_entry(V, &(OBJ)->vma_list, obj_link)              \
                for_each_until(!i915_vma_is_ggtt(V))

#endif