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authorAsahi Lina <lina@asahilina.net>2023-04-03 11:33:53 +0200
committerMiguel Ojeda <ojeda@kernel.org>2023-04-22 01:46:45 +0200
commitea76e08f4d901a450619831a255e9e0a4c0ed162 (patch)
treeda9bf4ca1eab8f9e0c9ac659dd7af3d50f88509e /rust/kernel
parentrust: uapi: Add UAPI crate (diff)
downloadlinux-ea76e08f4d901a450619831a255e9e0a4c0ed162.tar.xz
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rust: ioctl: Add ioctl number manipulation functions
Add simple 1:1 wrappers of the C ioctl number manipulation functions. Since these are macros we cannot bindgen them directly, and since they should be usable in const context we cannot use helper wrappers, so we'll have to reimplement them in Rust. Thankfully, the C headers do declare defines for the relevant bitfield positions, so we don't need to duplicate that. Signed-off-by: Asahi Lina <lina@asahilina.net> Link: https://lore.kernel.org/r/20230329-rust-uapi-v2-2-bca5fb4d4a12@asahilina.net [ Moved the `#![allow(non_snake_case)]` to the usual place. ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Diffstat (limited to 'rust/kernel')
-rw-r--r--rust/kernel/ioctl.rs72
-rw-r--r--rust/kernel/lib.rs1
2 files changed, 73 insertions, 0 deletions
diff --git a/rust/kernel/ioctl.rs b/rust/kernel/ioctl.rs
new file mode 100644
index 000000000000..c49e1a8d3fd0
--- /dev/null
+++ b/rust/kernel/ioctl.rs
@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! ioctl() number definitions
+//!
+//! C header: [`include/asm-generic/ioctl.h`](../../../../include/asm-generic/ioctl.h)
+
+#![allow(non_snake_case)]
+
+use crate::build_assert;
+
+/// Build an ioctl number, analogous to the C macro of the same name.
+#[inline(always)]
+const fn _IOC(dir: u32, ty: u32, nr: u32, size: usize) -> u32 {
+ build_assert!(dir <= uapi::_IOC_DIRMASK);
+ build_assert!(ty <= uapi::_IOC_TYPEMASK);
+ build_assert!(nr <= uapi::_IOC_NRMASK);
+ build_assert!(size <= (uapi::_IOC_SIZEMASK as usize));
+
+ (dir << uapi::_IOC_DIRSHIFT)
+ | (ty << uapi::_IOC_TYPESHIFT)
+ | (nr << uapi::_IOC_NRSHIFT)
+ | ((size as u32) << uapi::_IOC_SIZESHIFT)
+}
+
+/// Build an ioctl number for an argumentless ioctl.
+#[inline(always)]
+pub const fn _IO(ty: u32, nr: u32) -> u32 {
+ _IOC(uapi::_IOC_NONE, ty, nr, 0)
+}
+
+/// Build an ioctl number for an read-only ioctl.
+#[inline(always)]
+pub const fn _IOR<T>(ty: u32, nr: u32) -> u32 {
+ _IOC(uapi::_IOC_READ, ty, nr, core::mem::size_of::<T>())
+}
+
+/// Build an ioctl number for an write-only ioctl.
+#[inline(always)]
+pub const fn _IOW<T>(ty: u32, nr: u32) -> u32 {
+ _IOC(uapi::_IOC_WRITE, ty, nr, core::mem::size_of::<T>())
+}
+
+/// Build an ioctl number for a read-write ioctl.
+#[inline(always)]
+pub const fn _IOWR<T>(ty: u32, nr: u32) -> u32 {
+ _IOC(
+ uapi::_IOC_READ | uapi::_IOC_WRITE,
+ ty,
+ nr,
+ core::mem::size_of::<T>(),
+ )
+}
+
+/// Get the ioctl direction from an ioctl number.
+pub const fn _IOC_DIR(nr: u32) -> u32 {
+ (nr >> uapi::_IOC_DIRSHIFT) & uapi::_IOC_DIRMASK
+}
+
+/// Get the ioctl type from an ioctl number.
+pub const fn _IOC_TYPE(nr: u32) -> u32 {
+ (nr >> uapi::_IOC_TYPESHIFT) & uapi::_IOC_TYPEMASK
+}
+
+/// Get the ioctl number from an ioctl number.
+pub const fn _IOC_NR(nr: u32) -> u32 {
+ (nr >> uapi::_IOC_NRSHIFT) & uapi::_IOC_NRMASK
+}
+
+/// Get the ioctl size from an ioctl number.
+pub const fn _IOC_SIZE(nr: u32) -> usize {
+ ((nr >> uapi::_IOC_SIZESHIFT) & uapi::_IOC_SIZEMASK) as usize
+}
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index dd3b0d69fdd1..676995d4e460 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -37,6 +37,7 @@ mod allocator;
mod build_assert;
pub mod error;
pub mod init;
+pub mod ioctl;
pub mod prelude;
pub mod print;
mod static_assert;