On Wed, Jun 19, 2024 at 01:31:37AM +0200, Danilo Krummrich wrote: > From: Asahi Lina <lina@xxxxxxxxxxxxx> > > DRM drivers need to be able to declare which driver-specific ioctls they > support. Add an abstraction implementing the required types and a helper > macro to generate the ioctl definition inside the DRM driver. > > Note that this macro is not usable until further bits of the abstraction > are in place (but it will not fail to compile on its own, if not called). > > Signed-off-by: Asahi Lina <lina@xxxxxxxxxxxxx> > Signed-off-by: Danilo Krummrich <dakr@xxxxxxxxxx> Aside from the fixme commments in here I also had a bit a wishlist/ideas compilation of my own: https://lore.kernel.org/dri-devel/ZDfKLjKOfDHkEc1V@phenom.ffwll.local/#t Not sure where/how we want to record all these, and when we should try to fix them? -Sima > --- > rust/bindings/bindings_helper.h | 1 + > rust/kernel/drm/ioctl.rs | 153 ++++++++++++++++++++++++++++++++ > rust/kernel/drm/mod.rs | 5 ++ > rust/kernel/lib.rs | 2 + > rust/uapi/uapi_helper.h | 1 + > 5 files changed, 162 insertions(+) > create mode 100644 rust/kernel/drm/ioctl.rs > create mode 100644 rust/kernel/drm/mod.rs > > diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h > index 30ad2a0e22d7..ed25b686748e 100644 > --- a/rust/bindings/bindings_helper.h > +++ b/rust/bindings/bindings_helper.h > @@ -6,6 +6,7 @@ > * Sorted alphabetically. > */ > > +#include <drm/drm_ioctl.h> > #include <kunit/test.h> > #include <linux/errname.h> > #include <linux/ethtool.h> > diff --git a/rust/kernel/drm/ioctl.rs b/rust/kernel/drm/ioctl.rs > new file mode 100644 > index 000000000000..09ca7a8e7583 > --- /dev/null > +++ b/rust/kernel/drm/ioctl.rs > @@ -0,0 +1,153 @@ > +// SPDX-License-Identifier: GPL-2.0 OR MIT > +#![allow(non_snake_case)] > + > +//! DRM IOCTL definitions. > +//! > +//! C header: [`include/linux/drm/drm_ioctl.h`](srctree/include/linux/drm/drm_ioctl.h) > + > +use crate::ioctl; > + > +const BASE: u32 = uapi::DRM_IOCTL_BASE as u32; > + > +/// Construct a DRM ioctl number with no argument. > +#[inline(always)] > +pub const fn IO(nr: u32) -> u32 { > + ioctl::_IO(BASE, nr) > +} > + > +/// Construct a DRM ioctl number with a read-only argument. > +#[inline(always)] > +pub const fn IOR<T>(nr: u32) -> u32 { > + ioctl::_IOR::<T>(BASE, nr) > +} > + > +/// Construct a DRM ioctl number with a write-only argument. > +#[inline(always)] > +pub const fn IOW<T>(nr: u32) -> u32 { > + ioctl::_IOW::<T>(BASE, nr) > +} > + > +/// Construct a DRM ioctl number with a read-write argument. > +#[inline(always)] > +pub const fn IOWR<T>(nr: u32) -> u32 { > + ioctl::_IOWR::<T>(BASE, nr) > +} > + > +/// Descriptor type for DRM ioctls. Use the `declare_drm_ioctls!{}` macro to construct them. > +pub type DrmIoctlDescriptor = bindings::drm_ioctl_desc; > + > +/// This is for ioctl which are used for rendering, and require that the file descriptor is either > +/// for a render node, or if it’s a legacy/primary node, then it must be authenticated. > +pub const AUTH: u32 = bindings::drm_ioctl_flags_DRM_AUTH; > + > +/// This must be set for any ioctl which can change the modeset or display state. Userspace must > +/// call the ioctl through a primary node, while it is the active master. > +/// > +/// Note that read-only modeset ioctl can also be called by unauthenticated clients, or when a > +/// master is not the currently active one. > +pub const MASTER: u32 = bindings::drm_ioctl_flags_DRM_MASTER; > + > +/// Anything that could potentially wreak a master file descriptor needs to have this flag set. > +/// > +/// Current that’s only for the SETMASTER and DROPMASTER ioctl, which e.g. logind can call to > +/// force a non-behaving master (display compositor) into compliance. > +/// > +/// This is equivalent to callers with the SYSADMIN capability. > +pub const ROOT_ONLY: u32 = bindings::drm_ioctl_flags_DRM_ROOT_ONLY; > + > +/// This is used for all ioctl needed for rendering only, for drivers which support render nodes. > +/// This should be all new render drivers, and hence it should be always set for any ioctl with > +/// `AUTH` set. Note though that read-only query ioctl might have this set, but have not set > +/// DRM_AUTH because they do not require authentication. > +pub const RENDER_ALLOW: u32 = bindings::drm_ioctl_flags_DRM_RENDER_ALLOW; > + > +/// Internal structures used by the `declare_drm_ioctls!{}` macro. Do not use directly. > +#[doc(hidden)] > +pub mod internal { > + pub use bindings::drm_device; > + pub use bindings::drm_file; > + pub use bindings::drm_ioctl_desc; > +} > + > +/// Declare the DRM ioctls for a driver. > +/// > +/// Each entry in the list should have the form: > +/// > +/// `(ioctl_number, argument_type, flags, user_callback),` > +/// > +/// `argument_type` is the type name within the `bindings` crate. > +/// `user_callback` should have the following prototype: > +/// > +/// ```ignore > +/// fn foo(device: &kernel::drm::device::Device<Self>, > +/// data: &mut bindings::argument_type, > +/// file: &kernel::drm::file::File<Self::File>, > +/// ) > +/// ``` > +/// where `Self` is the drm::drv::Driver implementation these ioctls are being declared within. > +/// > +/// # Examples > +/// > +/// ```ignore > +/// kernel::declare_drm_ioctls! { > +/// (FOO_GET_PARAM, drm_foo_get_param, ioctl::RENDER_ALLOW, my_get_param_handler), > +/// } > +/// ``` > +/// > +#[macro_export] > +macro_rules! declare_drm_ioctls { > + ( $(($cmd:ident, $struct:ident, $flags:expr, $func:expr)),* $(,)? ) => { > + const IOCTLS: &'static [$crate::drm::ioctl::DrmIoctlDescriptor] = { > + use $crate::uapi::*; > + const _:() = { > + let i: u32 = $crate::uapi::DRM_COMMAND_BASE; > + // Assert that all the IOCTLs are in the right order and there are no gaps, > + // and that the sizeof of the specified type is correct. > + $( > + let cmd: u32 = $crate::macros::concat_idents!(DRM_IOCTL_, $cmd); > + ::core::assert!(i == $crate::ioctl::_IOC_NR(cmd)); > + ::core::assert!(core::mem::size_of::<$crate::uapi::$struct>() == > + $crate::ioctl::_IOC_SIZE(cmd)); > + let i: u32 = i + 1; > + )* > + }; > + > + let ioctls = &[$( > + $crate::drm::ioctl::internal::drm_ioctl_desc { > + cmd: $crate::macros::concat_idents!(DRM_IOCTL_, $cmd) as u32, > + func: { > + #[allow(non_snake_case)] > + unsafe extern "C" fn $cmd( > + raw_dev: *mut $crate::drm::ioctl::internal::drm_device, > + raw_data: *mut ::core::ffi::c_void, > + raw_file_priv: *mut $crate::drm::ioctl::internal::drm_file, > + ) -> core::ffi::c_int { > + // SAFETY: The DRM core ensures the device lives while callbacks are > + // being called. > + // > + // FIXME: Currently there is nothing enforcing that the types of the > + // dev/file match the current driver these ioctls are being declared > + // for, and it's not clear how to enforce this within the type system. > + let dev = $crate::drm::device::Device::borrow(raw_dev); > + // SAFETY: This is just the ioctl argument, which hopefully has the > + // right type (we've done our best checking the size). > + let data = unsafe { &mut *(raw_data as *mut $crate::uapi::$struct) }; > + // SAFETY: This is just the DRM file structure > + let file = unsafe { $crate::drm::file::File::from_raw(raw_file_priv) }; > + > + match $func(dev, data, &file) { > + Err(e) => e.to_errno(), > + Ok(i) => i.try_into() > + .unwrap_or($crate::error::code::ERANGE.to_errno()), > + } > + } > + Some($cmd) > + }, > + flags: $flags, > + name: $crate::c_str!(::core::stringify!($cmd)).as_char_ptr(), > + } > + ),*]; > + ioctls > + }; > + }; > +} > diff --git a/rust/kernel/drm/mod.rs b/rust/kernel/drm/mod.rs > new file mode 100644 > index 000000000000..9ec6d7cbcaf3 > --- /dev/null > +++ b/rust/kernel/drm/mod.rs > @@ -0,0 +1,5 @@ > +// SPDX-License-Identifier: GPL-2.0 OR MIT > + > +//! DRM subsystem abstractions. > + > +pub mod ioctl; > diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs > index 4a02946dbbd9..5a68b9a5fe03 100644 > --- a/rust/kernel/lib.rs > +++ b/rust/kernel/lib.rs > @@ -33,6 +33,8 @@ > pub mod device_id; > pub mod devres; > pub mod driver; > +#[cfg(CONFIG_DRM = "y")] > +pub mod drm; > pub mod error; > #[cfg(CONFIG_RUST_FW_LOADER_ABSTRACTIONS)] > pub mod firmware; > diff --git a/rust/uapi/uapi_helper.h b/rust/uapi/uapi_helper.h > index 08f5e9334c9e..ed42a456da2e 100644 > --- a/rust/uapi/uapi_helper.h > +++ b/rust/uapi/uapi_helper.h > @@ -7,5 +7,6 @@ > */ > > #include <uapi/asm-generic/ioctl.h> > +#include <uapi/drm/drm.h> > #include <uapi/linux/mii.h> > #include <uapi/linux/ethtool.h> > -- > 2.45.1 > -- Simona Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch
