// SPDX-License-Identifier: GPL-2.0 OR MIT //! DRM GEM API//!//! C header: [`include/drm/drm_gem.h`](srctree/include/drm/drm_gem.h) use crate::{    bindings,    drm::{        self,        device::{            DeviceContext,            Registered, //        },        driver::{            AllocImpl,            AllocOps, //        },    },    error::to_result,    prelude::*,    sync::aref::{        ARef,        AlwaysRefCounted, //    },    types::Opaque,};use core::{    marker::PhantomData,    ops::Deref,    ptr::NonNull, //}; #[cfg(CONFIG_RUST_DRM_GEM_SHMEM_HELPER)]pub mod shmem; /// A macro for implementing [`AlwaysRefCounted`] for any GEM object type.////// Since all GEM objects use the same refcounting scheme.#[macro_export]macro_rules! impl_aref_for_gem_obj {    (        impl $( <$( $tparam_id:ident ),+> )? for $type:ty        $(            where                $( $bind_param:path : $bind_trait:path ),+        )?    ) => {        // SAFETY: All GEM objects are refcounted.        unsafe impl $( <$( $tparam_id ),+> )? $crate::sync::aref::AlwaysRefCounted for $type        where            Self: IntoGEMObject,            $( $( $bind_param : $bind_trait ),+ )?        {            fn inc_ref(&self) {                // SAFETY: The existence of a shared reference guarantees that the refcount is                // non-zero.                unsafe { bindings::drm_gem_object_get(self.as_raw()) };            }             unsafe fn dec_ref(obj: core::ptr::NonNull<Self>) {                // SAFETY: `obj` is a valid pointer to an `Object<T>`.                let obj = unsafe { obj.as_ref() }.as_raw();                 // SAFETY: The safety requirements guarantee that the refcount is non-zero.                unsafe { bindings::drm_gem_object_put(obj) };            }        }    };}#[cfg_attr(not(CONFIG_RUST_DRM_GEM_SHMEM_HELPER), allow(unused))]pub(crate) use impl_aref_for_gem_obj; /// A type alias for retrieving a [`Driver`]s [`DriverFile`] implementation from its/// [`DriverObject`] implementation.////// [`Driver`]: drm::Driver/// [`DriverFile`]: drm::file::DriverFilepub type DriverFile<T> = drm::File<<<T as DriverObject>::Driver as drm::Driver>::File>; /// A type alias for retrieving the current [`AllocImpl`] for a given [`DriverObject`].////// [`Driver`]: drm::Driverpub type DriverAllocImpl<T, Ctx = Registered> =    <<T as DriverObject>::Driver as drm::Driver>::Object<Ctx>; /// GEM object functions, which must be implemented by drivers.pub trait DriverObject: Sync + Send + Sized {    /// Parent `Driver` for this object.    type Driver: drm::Driver;     /// The data type to use for passing arguments to [`DriverObject::new`].    type Args;     /// Create a new driver data object for a GEM object of a given size.    fn new<Ctx: DeviceContext>(        dev: &drm::Device<Self::Driver, Ctx>,        size: usize,        args: Self::Args,    ) -> impl PinInit<Self, Error>;     /// Open a new handle to an existing object, associated with a File.    fn open(_obj: &DriverAllocImpl<Self>, _file: &DriverFile<Self>) -> Result {        Ok(())    }     /// Close a handle to an existing object, associated with a File.    fn close(_obj: &DriverAllocImpl<Self>, _file: &DriverFile<Self>) {}} /// Trait that represents a GEM object subtypepub trait IntoGEMObject: Sized + super::private::Sealed + AlwaysRefCounted {    /// Returns a reference to the raw `drm_gem_object` structure, which must be valid as long as    /// this owning object is valid.    fn as_raw(&self) -> *mut bindings::drm_gem_object;     /// Converts a pointer to a `struct drm_gem_object` into a reference to `Self`.    ///    /// # Safety    ///    /// - `self_ptr` must be a valid pointer to `Self`.    /// - The caller promises that holding the immutable reference returned by this function does    ///   not violate rust's data aliasing rules and remains valid throughout the lifetime of `'a`.    unsafe fn from_raw<'a>(self_ptr: *mut bindings::drm_gem_object) -> &'a Self;} extern "C" fn open_callback<T: DriverObject>(    raw_obj: *mut bindings::drm_gem_object,    raw_file: *mut bindings::drm_file,) -> core::ffi::c_int {    // SAFETY: `open_callback` is only ever called with a valid pointer to a `struct drm_file`.    let file = unsafe { DriverFile::<T>::from_raw(raw_file) };     // SAFETY:    // * `open_callback` is specified in the AllocOps structure for `DriverObject`, ensuring that    //   `raw_obj` is contained within a `DriverAllocImpl<T>`    // * It is only possible for `open_callback` to be called after device registration, ensuring    //   that the object's device is in the `Registered` state.    let obj: &DriverAllocImpl<T> = unsafe { IntoGEMObject::from_raw(raw_obj) };     match T::open(obj, file) {        Err(e) => e.to_errno(),        Ok(()) => 0,    }} extern "C" fn close_callback<T: DriverObject>(    raw_obj: *mut bindings::drm_gem_object,    raw_file: *mut bindings::drm_file,) {    // SAFETY: `open_callback` is only ever called with a valid pointer to a `struct drm_file`.    let file = unsafe { DriverFile::<T>::from_raw(raw_file) };     // SAFETY: `close_callback` is specified in the AllocOps structure for `Object<T>`, ensuring    // that `raw_obj` is indeed contained within a `Object<T>`.    let obj: &DriverAllocImpl<T> = unsafe { IntoGEMObject::from_raw(raw_obj) };     T::close(obj, file);} impl<T: DriverObject, Ctx: DeviceContext> IntoGEMObject for Object<T, Ctx> {    fn as_raw(&self) -> *mut bindings::drm_gem_object {        self.obj.get()    }     unsafe fn from_raw<'a>(self_ptr: *mut bindings::drm_gem_object) -> &'a Self {        // SAFETY: `obj` is guaranteed to be in an `Object<T>` via the safety contract of this        // function        unsafe { &*crate::container_of!(Opaque::cast_from(self_ptr), Object<T, Ctx>, obj) }    }} /// Base operations shared by all GEM object classespub trait BaseObject: IntoGEMObject {    /// Returns the size of the object in bytes.    fn size(&self) -> usize {        // SAFETY: `self.as_raw()` is guaranteed to be a pointer to a valid `struct drm_gem_object`.        unsafe { (*self.as_raw()).size }    }     /// Creates a new handle for the object associated with a given `File`    /// (or returns an existing one).    fn create_handle<D, F>(&self, file: &drm::File<F>) -> Result<u32>    where        Self: AllocImpl<Driver = D>,        D: drm::Driver<Object<Registered> = Self, File = F>,        F: drm::file::DriverFile<Driver = D>,    {        let mut handle: u32 = 0;        // SAFETY: The arguments are all valid per the type invariants.        to_result(unsafe {            bindings::drm_gem_handle_create(file.as_raw().cast(), self.as_raw(), &mut handle)        })?;        Ok(handle)    }     /// Looks up an object by its handle for a given `File`.    fn lookup_handle<D, F>(file: &drm::File<F>, handle: u32) -> Result<ARef<Self>>    where        Self: AllocImpl<Driver = D>,        D: drm::Driver<Object<Registered> = Self, File = F>,        F: drm::file::DriverFile<Driver = D>,    {        // SAFETY: The arguments are all valid per the type invariants.        let ptr = unsafe { bindings::drm_gem_object_lookup(file.as_raw().cast(), handle) };        if ptr.is_null() {            return Err(ENOENT);        }         // SAFETY:        // - A `drm::Driver` can only have a single `File` implementation.        // - `file` uses the same `drm::Driver` as `Self`.        // - Therefore, we're guaranteed that `ptr` must be a gem object embedded within `Self`.        // - And we check if the pointer is null befoe calling from_raw(), ensuring that `ptr` is a        //   valid pointer to an initialized `Self`.        let obj = unsafe { Self::from_raw(ptr) };         // SAFETY:        // - We take ownership of the reference of `drm_gem_object_lookup()`.        // - Our `NonNull` comes from an immutable reference, thus ensuring it is a valid pointer to        //   `Self`.        Ok(unsafe { ARef::from_raw(obj.into()) })    }     /// Creates an mmap offset to map the object from userspace.    fn create_mmap_offset(&self) -> Result<u64> {        // SAFETY: The arguments are valid per the type invariant.        to_result(unsafe { bindings::drm_gem_create_mmap_offset(self.as_raw()) })?;         // SAFETY: The arguments are valid per the type invariant.        Ok(unsafe { bindings::drm_vma_node_offset_addr(&raw mut (*self.as_raw()).vma_node) })    }} impl<T: IntoGEMObject> BaseObject for T {} /// Crate-private base operations shared by all GEM object classes.#[cfg_attr(not(CONFIG_RUST_DRM_GEM_SHMEM_HELPER), expect(unused))]pub(crate) trait BaseObjectPrivate: IntoGEMObject {    /// Return a pointer to this object's dma_resv.    fn raw_dma_resv(&self) -> *mut bindings::dma_resv {        // SAFETY: `self.as_raw()` always returns a valid pointer to the base DRM GEM object.        unsafe { (*self.as_raw()).resv }    }} impl<T: IntoGEMObject> BaseObjectPrivate for T {} /// A base GEM object.////// # Invariants////// * `self.obj` is a valid instance of a `struct drm_gem_object`./// * Any type invariants of `Ctx` apply to the parent DRM device for this GEM object.#[repr(C)]#[pin_data]pub struct Object<T: DriverObject + Send + Sync, Ctx: DeviceContext = Registered> {    obj: Opaque<bindings::drm_gem_object>,    #[pin]    data: T,    _ctx: PhantomData<Ctx>,} impl<T: DriverObject, Ctx: DeviceContext> Object<T, Ctx> {    const OBJECT_FUNCS: bindings::drm_gem_object_funcs = bindings::drm_gem_object_funcs {        free: Some(Self::free_callback),        open: Some(open_callback::<T>),        close: Some(close_callback::<T>),        print_info: None,        export: None,        pin: None,        unpin: None,        get_sg_table: None,        vmap: None,        vunmap: None,        mmap: None,        status: None,        vm_ops: core::ptr::null_mut(),        evict: None,        rss: None,    };     /// Create a new GEM object.    pub fn new(        dev: &drm::Device<T::Driver, Ctx>,        size: usize,        args: T::Args,    ) -> Result<ARef<Self>> {        let obj: Pin<KBox<Self>> = KBox::pin_init(            try_pin_init!(Self {                obj: Opaque::new(bindings::drm_gem_object::default()),                data <- T::new(dev, size, args),                _ctx: PhantomData,            }),            GFP_KERNEL,        )?;         // SAFETY: `obj.as_raw()` is guaranteed to be valid by the initialization above.        unsafe { (*obj.as_raw()).funcs = &Self::OBJECT_FUNCS };         // INVARIANT: `dev` and the GEM object are in the same state at the moment, and upgrading        // the typestate in `dev` will not carry over to the GEM object.        if let Err(err) =            // SAFETY: The arguments are all valid per the type invariants.            to_result(unsafe {                bindings::drm_gem_object_init(dev.as_raw(), obj.obj.get(), size)            })        {            // SAFETY: `drm_gem_object_init()` initializes the private GEM object state before            // failing, so `drm_gem_private_object_fini()` is the matching cleanup.            unsafe { bindings::drm_gem_private_object_fini(obj.obj.get()) };            return Err(err);        }         // SAFETY: We will never move out of `Self` as `ARef<Self>` is always treated as pinned.        let ptr = KBox::into_raw(unsafe { Pin::into_inner_unchecked(obj) });         // SAFETY: `ptr` comes from `KBox::into_raw` and hence can't be NULL.        let ptr = unsafe { NonNull::new_unchecked(ptr) };         // SAFETY: We take over the initial reference count from `drm_gem_object_init()`.        Ok(unsafe { ARef::from_raw(ptr) })    }     /// Returns the `Device` that owns this GEM object.    pub fn dev(&self) -> &drm::Device<T::Driver, Ctx> {        // SAFETY:        // - `struct drm_gem_object.dev` is initialized and valid for as long as the GEM        //   object lives.        // - The device we used for creating the gem object is passed as &drm::Device<T::Driver> to        //   Object::<T>::new(), so we know that `T::Driver` is the right generic parameter to use        //   here.        // - Any type invariants of `Ctx` are upheld by using the same `Ctx` for the `Device` we        //   return.        unsafe { drm::Device::from_raw((*self.as_raw()).dev) }    }     fn as_raw(&self) -> *mut bindings::drm_gem_object {        self.obj.get()    }     extern "C" fn free_callback(obj: *mut bindings::drm_gem_object) {        let ptr: *mut Opaque<bindings::drm_gem_object> = obj.cast();         // SAFETY: All of our objects are of type `Object<T>`.        let this = unsafe { crate::container_of!(ptr, Self, obj) };         // SAFETY: The C code only ever calls this callback with a valid pointer to a `struct        // drm_gem_object`.        unsafe { bindings::drm_gem_object_release(obj) };         // SAFETY: All of our objects are allocated via `KBox`, and we're in the        // free callback which guarantees this object has zero remaining references,        // so we can drop it.        let _ = unsafe { KBox::from_raw(this) };    }} impl_aref_for_gem_obj! {    impl<T, C> for Object<T, C>    where        T: DriverObject,        C: DeviceContext} impl<T: DriverObject, Ctx: DeviceContext> super::private::Sealed for Object<T, Ctx> {} impl<T: DriverObject, Ctx: DeviceContext> Deref for Object<T, Ctx> {    type Target = T;     fn deref(&self) -> &Self::Target {        &self.data    }} impl<T: DriverObject, Ctx: DeviceContext> AllocImpl for Object<T, Ctx> {    type Driver = T::Driver;     const ALLOC_OPS: AllocOps = AllocOps {        gem_create_object: None,        prime_handle_to_fd: None,        prime_fd_to_handle: None,        gem_prime_import: None,        gem_prime_import_sg_table: None,        dumb_create: None,        dumb_map_offset: None,    };} pub(super) const fn create_fops() -> bindings::file_operations {    let mut fops: bindings::file_operations = pin_init::zeroed();     fops.owner = core::ptr::null_mut();    fops.open = Some(bindings::drm_open);    fops.release = Some(bindings::drm_release);    fops.unlocked_ioctl = Some(bindings::drm_ioctl);    #[cfg(CONFIG_COMPAT)]    {        fops.compat_ioctl = Some(bindings::drm_compat_ioctl);    }    fops.poll = Some(bindings::drm_poll);    fops.read = Some(bindings::drm_read);    fops.llseek = Some(bindings::noop_llseek);    fops.mmap = Some(bindings::drm_gem_mmap);    fops.fop_flags = bindings::FOP_UNSIGNED_OFFSET;     fops}