The following FFI types are replaced compared to `core::ffi`:
1. `char` type is now always mapped to `u8`, since kernel uses
`-funsigned-char` on the C code. `core::ffi` maps it to platform
default ABI, which can be either signed or unsigned.
2. `long` is now always mapped to `isize`. It's very common in the
kernel to use `long` to represent a pointer-sized integer, and in
fact `intptr_t` is a typedef of `long` in the kernel. Enforce this
mapping rather than mapping to `i32/i64` depending on platform can
save us a lot of unnecessary casts.
Signed-off-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240913213041.395655-5-gary@garyguo.net
[ Moved `uaccess` changes from the next commit, since they were
irrefutable patterns that Rust >= 1.82.0 warns about. Reworded
slightly and reformatted a few documentation comments. Rebased on
top of `rust-next`. Added the removal of two casts to avoid Clippy
warnings. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
#![no_std]
-pub use core::ffi::*;
+macro_rules! alias {
+ ($($name:ident = $ty:ty;)*) => {$(
+ #[allow(non_camel_case_types, missing_docs)]
+ pub type $name = $ty;
+
+ // Check size compatibility with `core`.
+ const _: () = assert!(
+ core::mem::size_of::<$name>() == core::mem::size_of::<core::ffi::$name>()
+ );
+ )*}
+}
+
+alias! {
+ // `core::ffi::c_char` is either `i8` or `u8` depending on architecture. In the kernel, we use
+ // `-funsigned-char` so it's always mapped to `u8`.
+ c_char = u8;
+
+ c_schar = i8;
+ c_uchar = u8;
+
+ c_short = i16;
+ c_ushort = u16;
+
+ c_int = i32;
+ c_uint = u32;
+
+ // In the kernel, `intptr_t` is defined to be `long` in all platforms, so we can map the type to
+ // `isize`.
+ c_long = isize;
+ c_ulong = usize;
+
+ c_longlong = i64;
+ c_ulonglong = u64;
+}
+
+pub use core::ffi::c_void;
/// Returns the error encoded as a pointer.
pub fn to_ptr<T>(self) -> *mut T {
- #[cfg_attr(target_pointer_width = "32", allow(clippy::useless_conversion))]
// SAFETY: `self.0` is a valid error due to its invariant.
- unsafe {
- bindings::ERR_PTR(self.0.get().into()) as *mut _
- }
+ unsafe { bindings::ERR_PTR(self.0.get() as _) as *mut _ }
}
/// Returns a string representing the error, if one exists.
/// One of the following: `bindings::request_firmware`, `bindings::firmware_request_nowarn`,
/// `bindings::firmware_request_platform`, `bindings::request_firmware_direct`.
struct FwFunc(
- unsafe extern "C" fn(*mut *const bindings::firmware, *const i8, *mut bindings::device) -> i32,
+ unsafe extern "C" fn(*mut *const bindings::firmware, *const u8, *mut bindings::device) -> i32,
);
impl FwFunc {
// SAFETY: Ioctl calls can borrow the private data of the file.
let device = unsafe { <T::Ptr as ForeignOwnable>::borrow(private) };
- match T::ioctl(device, cmd, arg as usize) {
+ match T::ioctl(device, cmd, arg) {
Ok(ret) => ret as c_long,
Err(err) => err.to_errno() as c_long,
}
// SAFETY: Ioctl calls can borrow the private data of the file.
let device = unsafe { <T::Ptr as ForeignOwnable>::borrow(private) };
- match T::compat_ioctl(device, cmd, arg as usize) {
+ match T::compat_ioctl(device, cmd, arg) {
Ok(ret) => ret as c_long,
Err(err) => err.to_errno() as c_long,
}
alloc::Flags,
bindings,
error::Result,
- ffi::{c_ulong, c_void},
+ ffi::c_void,
prelude::*,
transmute::{AsBytes, FromBytes},
};
if len > self.length {
return Err(EFAULT);
}
- let Ok(len_ulong) = c_ulong::try_from(len) else {
- return Err(EFAULT);
- };
- // SAFETY: `out_ptr` points into a mutable slice of length `len_ulong`, so we may write
+ // SAFETY: `out_ptr` points into a mutable slice of length `len`, so we may write
// that many bytes to it.
- let res =
- unsafe { bindings::copy_from_user(out_ptr, self.ptr as *const c_void, len_ulong) };
+ let res = unsafe { bindings::copy_from_user(out_ptr, self.ptr as *const c_void, len) };
if res != 0 {
return Err(EFAULT);
}
if len > self.length {
return Err(EFAULT);
}
- let Ok(len_ulong) = c_ulong::try_from(len) else {
- return Err(EFAULT);
- };
let mut out: MaybeUninit<T> = MaybeUninit::uninit();
// SAFETY: The local variable `out` is valid for writing `size_of::<T>()` bytes.
//
bindings::_copy_from_user(
out.as_mut_ptr().cast::<c_void>(),
self.ptr as *const c_void,
- len_ulong,
+ len,
)
};
if res != 0 {
if len > self.length {
return Err(EFAULT);
}
- let Ok(len_ulong) = c_ulong::try_from(len) else {
- return Err(EFAULT);
- };
- // SAFETY: `data_ptr` points into an immutable slice of length `len_ulong`, so we may read
+ // SAFETY: `data_ptr` points into an immutable slice of length `len`, so we may read
// that many bytes from it.
- let res = unsafe { bindings::copy_to_user(self.ptr as *mut c_void, data_ptr, len_ulong) };
+ let res = unsafe { bindings::copy_to_user(self.ptr as *mut c_void, data_ptr, len) };
if res != 0 {
return Err(EFAULT);
}
if len > self.length {
return Err(EFAULT);
}
- let Ok(len_ulong) = c_ulong::try_from(len) else {
- return Err(EFAULT);
- };
// SAFETY: The reference points to a value of type `T`, so it is valid for reading
// `size_of::<T>()` bytes.
//
bindings::_copy_to_user(
self.ptr as *mut c_void,
(value as *const T).cast::<c_void>(),
- len_ulong,
+ len,
)
};
if res != 0 {
projects / thirdparty / linux.git / commitdiff
