Commit c284d3e4 authored by Asahi Lina's avatar Asahi Lina Committed by Danilo Krummrich
Browse files

rust: drm: gem: Add GEM object abstraction 



DRM GEM is the DRM memory management subsystem used by most modern
drivers; add a Rust abstraction for DRM GEM.

This includes the BaseObject trait, which contains operations shared by
all GEM object classes.

Signed-off-by: default avatarAsahi Lina <lina@asahilina.net>
Reviewed-by: default avatarAlyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: default avatarLyude Paul <lyude@redhat.com>
Link: https://lore.kernel.org/r/20250410235546.43736-8-dakr@kernel.org
[ Rework of GEM object abstractions
    * switch to the Opaque<T> type
    * fix (mutable) references to struct drm_gem_object (which in this
      context is UB)
    * drop all custom reference types in favor of AlwaysRefCounted
    * bunch of minor changes and simplifications (e.g. IntoGEMObject
      trait)
    * write and fix safety and invariant comments
    * remove necessity for and convert 'as' casts
    * original source archive: https://archive.is/dD5SL



  - Danilo ]
[ Fix missing CONFIG_DRM guards in rust/helpers/drm.c. - Danilo ]
Signed-off-by: default avatarDanilo Krummrich <dakr@kernel.org>
parent a98a73be

rust/bindings/bindings_helper.h

+2 −0
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 
#include <drm/drm_device.h>

#include <drm/drm_drv.h>

#include <drm/drm_file.h>

#include <drm/drm_gem.h>

#include <drm/drm_ioctl.h>

#include <kunit/test.h>

#include <linux/auxiliary_bus.h>
@@ -60,3 +61,4 @@ const gfp_t RUST_CONST_HELPER___GFP_ZERO = __GFP_ZERO; 
const gfp_t RUST_CONST_HELPER___GFP_HIGHMEM = ___GFP_HIGHMEM;

const gfp_t RUST_CONST_HELPER___GFP_NOWARN = ___GFP_NOWARN;

const blk_features_t RUST_CONST_HELPER_BLK_FEAT_ROTATIONAL = BLK_FEAT_ROTATIONAL;

const fop_flags_t RUST_CONST_HELPER_FOP_UNSIGNED_OFFSET = FOP_UNSIGNED_OFFSET;

rust/helpers/drm.c

0 → 100644
+23 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0



#include <drm/drm_gem.h>

#include <drm/drm_vma_manager.h>



#ifdef CONFIG_DRM



void rust_helper_drm_gem_object_get(struct drm_gem_object *obj)

{

	drm_gem_object_get(obj);

}



void rust_helper_drm_gem_object_put(struct drm_gem_object *obj)

{

	drm_gem_object_put(obj);

}



__u64 rust_helper_drm_vma_node_offset_addr(struct drm_vma_offset_node *node)

{

	return drm_vma_node_offset_addr(node);

}



#endif

rust/helpers/helpers.c

+1 −0
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ 
#include "cpumask.c"

#include "cred.c"

#include "device.c"

#include "drm.c"

#include "err.c"

#include "fs.c"

#include "io.c"

rust/kernel/drm/device.rs

+3 −1
Original line number Diff line number Diff line
@@ -89,9 +89,11 @@ impl<T: drm::Driver> Device<T> { 
        driver_features: drm::driver::FEAT_GEM,

        ioctls: T::IOCTLS.as_ptr(),

        num_ioctls: T::IOCTLS.len() as i32,

        fops: core::ptr::null_mut() as _,

        fops: &Self::GEM_FOPS as _,

    };



    const GEM_FOPS: bindings::file_operations = drm::gem::create_fops();



    /// Create a new `drm::Device` for a `drm::Driver`.

    pub fn new(dev: &device::Device, data: impl PinInit<T::Data, Error>) -> Result<ARef<Self>> {

        // SAFETY:

rust/kernel/drm/driver.rs

+1 −1
Original line number Diff line number Diff line
@@ -88,7 +88,7 @@ pub struct AllocOps { 
}



/// Trait for memory manager implementations. Implemented internally.

pub trait AllocImpl: super::private::Sealed {

pub trait AllocImpl: super::private::Sealed + drm::gem::IntoGEMObject {

    /// The C callback operations for this memory manager.

    const ALLOC_OPS: AllocOps;

}