// SPDX-License-Identifier: GPL-2.0 OR MIT
//! DRM IOCTL definitions.
//!
//! C header: [`include/drm/drm_ioctl.h`](srctree/include/drm/drm_ioctl.h)
use crate::ioctl;
const BASE: u32 = uapi::DRM_IOCTL_BASE as u32;
/// Construct a DRM ioctl number with no argument.
#[allow(non_snake_case)]
#[inline(always)]
pub const fn IO(nr: u32) -> u32 {
ioctl::_IO(BASE, nr)
}
/// Construct a DRM ioctl number with a read-only argument.
#[allow(non_snake_case)]
#[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.
#[allow(non_snake_case)]
#[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.
#[allow(non_snake_case)]
#[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;
/// Cast an [`Ioctl`] DRM device pointer to [`Registered`], preserving the driver type
/// parameter `T`.
///
/// Used by [`declare_drm_ioctls!`] to anchor type inference.
#[doc(hidden)]
#[inline]
pub const fn __dev_ctx_cast<T: crate::drm::Driver>(
ptr: *const crate::drm::Device<T, crate::drm::Ioctl>,
) -> *const crate::drm::Device<T, crate::drm::Registered> {
ptr.cast()
}
}
/// 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<Self, kernel::drm::Registered>,
/// reg_data: &Self::RegistrationData<'_>,
/// data: &mut uapi::argument_type,
/// file: &kernel::drm::File<Self::File>,
/// ) -> Result<u32>
/// ```
/// 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 size 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: *mut $crate::drm::ioctl::internal::drm_file,
) -> core::ffi::c_int {
// SAFETY:
// - The DRM core ensures the device lives while callbacks are being
// called.
// - The DRM device must have been registered when we're called through
// an IOCTL.
//
// INVARIANT: The `Ioctl` context requires that the device has been
// registered via `drm_dev_register()` at some point; the DRM core
// guarantees this for ioctl dispatch callbacks.
//
// FIXME: Currently there is nothing enforcing that the types of the
// dev/file match the current driver these ioctls are being declared
// for, and it's not clear how to enforce this within the type system.
let dev: &$crate::drm::device::Device<_, $crate::drm::Ioctl> =
$crate::drm::device::Device::from_raw(raw_dev);
// Type-inference anchor: the closure is never called but ties `dev`'s
// type to `$func`'s first parameter, which the compiler cannot infer
// through method resolution and associated-type projections alone.
#[allow(unreachable_code)]
let _ = || {
let __ptr = $crate::drm::ioctl::internal::__dev_ctx_cast(
::core::ptr::from_ref(dev),
);
$func(
// SAFETY: This closure is never executed; the dereference
// exists purely to unify the type parameter with `$func`.
// The pointer is valid regardless.
unsafe { &*__ptr },
unreachable!(),
unreachable!(),
unreachable!(),
)
};
// Enforce that the handler accepts higher-ranked
// lifetimes, preventing it from requiring 'static
// references that could escape this scope.
let _: for<'a> fn(&'a _, &'a _, &'a mut _, &'a _) -> _ = $func;
let Some(guard) = dev.registration_guard() else {
return $crate::error::code::ENODEV.to_errno();
};
// SAFETY: The ioctl argument has size `_IOC_SIZE(cmd)`, which we
// asserted above matches the size of this type, and all bit patterns of
// UAPI structs must be valid.
// The `ioctl` argument is exclusively owned by the handler
// and guaranteed by the C implementation (`drm_ioctl()`) to remain
// valid for the entire lifetime of the reference taken here.
// There is no concurrent access or aliasing; no other references
// to this object exist during this call.
let data = unsafe { &mut *(raw_data.cast::<$crate::uapi::$struct>()) };
// SAFETY: This is just the DRM file structure
let file = unsafe { $crate::drm::File::from_raw(raw_file) };
match guard.registration_data_with(|reg_data| {
$func(&*guard, reg_data, data, file)
}) {
Err(e) => e.to_errno(),
Ok(i) => i.try_into()
.unwrap_or($crate::error::code::ERANGE.to_errno()),
}
}
Some($cmd)
},
flags: $flags,
name: $crate::str::as_char_ptr_in_const_context(
$crate::c_str!(::core::stringify!($cmd)),
),
}
),*];
ioctls
};
};
}
