diff options
Diffstat (limited to 'rust/kernel/drm/ioctl.rs')
| -rw-r--r-- | rust/kernel/drm/ioctl.rs | 147 |
1 files changed, 147 insertions, 0 deletions
diff --git a/rust/kernel/drm/ioctl.rs b/rust/kernel/drm/ioctl.rs new file mode 100644 index 000000000000..10304efbd5f1 --- /dev/null +++ b/rust/kernel/drm/ioctl.rs @@ -0,0 +1,147 @@ +// SPDX-License-Identifier: GPL-2.0 OR MIT +#![allow(non_snake_case)] + +//! DRM IOCTL definitions. +//! +//! C header: [`include/linux/drm/drm_ioctl.h`](../../../../include/linux/drm/drm_ioctl.h) + +use crate::ioctl; + +const BASE: u32 = bindings::DRM_IOCTL_BASE as u32; + +/// Construct a DRM ioctl number with no argument. +pub const fn IO(nr: u32) -> u32 { + ioctl::_IO(BASE, nr) +} + +/// Construct a DRM ioctl number with a read-only argument. +pub const fn IOR<T>(nr: u32) -> u32 { + ioctl::_IOR::<T>(BASE, nr) +} + +/// Construct a DRM ioctl number with a write-only argument. +pub const fn IOW<T>(nr: u32) -> u32 { + ioctl::_IOW::<T>(BASE, nr) +} + +/// Construct a DRM ioctl number with a read-write argument. +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; + +/// Whether drm_ioctl_desc.func should be called with the DRM BKL held or not. Enforced as the +/// default for all modern drivers, hence there should never be a need to set this flag. +/// +/// Do not use anywhere else than for the VBLANK_WAIT IOCTL, which is the only legacy IOCTL which +/// needs this. +pub const UNLOCKED: u32 = bindings::drm_ioctl_flags_DRM_UNLOCKED; + +/// 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; + +/// 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: +/// +/// ``` +/// 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 +/// +/// ``` +/// 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] = { + const _:() = { + let i: u32 = $crate::bindings::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 = $crate::macros::concat_idents!($crate::bindings::DRM_IOCTL_, $cmd); + ::core::assert!(i == $crate::ioctl::_IOC_NR(cmd)); + ::core::assert!(core::mem::size_of::<$crate::bindings::$struct>() == $crate::ioctl::_IOC_SIZE(cmd)); + let i: u32 = i + 1; + )* + }; + + let ioctls = &[$( + $crate::bindings::drm_ioctl_desc { + cmd: $crate::macros::concat_idents!($crate::bindings::DRM_IOCTL_, $cmd) as u32, + func: { + #[allow(non_snake_case)] + unsafe extern "C" fn $cmd( + raw_dev: *mut $crate::bindings::drm_device, + raw_data: *mut ::core::ffi::c_void, + raw_file_priv: *mut $crate::bindings::drm_file, + ) -> core::ffi::c_int { + // SAFETY: We never drop this, and 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 = ::core::mem::ManuallyDrop::new(unsafe { + $crate::drm::device::Device::from_raw(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 $crate::bindings::$struct) }; + // SAFETY: This is just the DRM file structure + let file = unsafe { $crate::drm::file::File::from_raw(raw_file_priv) }; + + match $func(&*dev, data, &file) { + Err(e) => e.to_kernel_errno(), + Ok(i) => i.try_into().unwrap_or(ERANGE.to_kernel_errno()), + } + } + Some($cmd) + }, + flags: $flags, + name: $crate::c_str!(::core::stringify!($cmd)).as_char_ptr(), + } + ),*]; + ioctls + }; + }; +} |