--- /dev/null
+From stable+bounces-121622-greg=kroah.com@vger.kernel.org Sun Mar 9 21:42:38 2025
+From: Miguel Ojeda <ojeda@kernel.org>
+Date: Sun, 9 Mar 2025 21:42:16 +0100
+Subject: rust: finish using custom FFI integer types
+To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Sasha Levin <sashal@kernel.org>, stable@vger.kernel.org
+Cc: Danilo Krummrich <dakr@kernel.org>, Alice Ryhl <aliceryhl@google.com>, Alyssa Ross <hi@alyssa.is>, NoisyCoil <noisycoil@disroot.org>, patches@lists.linux.dev, Miguel Ojeda <ojeda@kernel.org>
+Message-ID: <20250309204217.1553389-2-ojeda@kernel.org>
+
+From: Miguel Ojeda <ojeda@kernel.org>
+
+commit 27c7518e7f1ccaaa43eb5f25dc362779d2dc2ccb upstream.
+
+In the last kernel cycle we migrated most of the `core::ffi` cases in
+commit d072acda4862 ("rust: use custom FFI integer types"):
+
+ Currently FFI integer types are defined in libcore. This commit
+ creates the `ffi` crate and asks bindgen to use that crate for FFI
+ integer types instead of `core::ffi`.
+
+ This commit is preparatory and no type changes are made in this
+ commit yet.
+
+Finish now the few remaining/new cases so that we perform the actual
+remapping in the next commit as planned.
+
+Acked-by: Jocelyn Falempe <jfalempe@redhat.com> # drm
+Link: https://lore.kernel.org/rust-for-linux/CANiq72m_rg42SvZK=bF2f0yEoBLVA33UBhiAsv8THhVu=G2dPA@mail.gmail.com/
+Link: https://lore.kernel.org/all/cc9253fa-9d5f-460b-9841-94948fb6580c@redhat.com/
+Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/gpu/drm/drm_panic_qr.rs | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+--- a/drivers/gpu/drm/drm_panic_qr.rs
++++ b/drivers/gpu/drm/drm_panic_qr.rs
+@@ -931,7 +931,7 @@ impl QrImage<'_> {
+ /// They must remain valid for the duration of the function call.
+ #[no_mangle]
+ pub unsafe extern "C" fn drm_panic_qr_generate(
+- url: *const i8,
++ url: *const kernel::ffi::c_char,
+ data: *mut u8,
+ data_len: usize,
+ data_size: usize,
--- /dev/null
+From stable+bounces-121623-greg=kroah.com@vger.kernel.org Sun Mar 9 21:42:43 2025
+From: Miguel Ojeda <ojeda@kernel.org>
+Date: Sun, 9 Mar 2025 21:42:17 +0100
+Subject: rust: map `long` to `isize` and `char` to `u8`
+To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Sasha Levin <sashal@kernel.org>, stable@vger.kernel.org
+Cc: Danilo Krummrich <dakr@kernel.org>, Alice Ryhl <aliceryhl@google.com>, Alyssa Ross <hi@alyssa.is>, NoisyCoil <noisycoil@disroot.org>, patches@lists.linux.dev, Miguel Ojeda <ojeda@kernel.org>
+Message-ID: <20250309204217.1553389-3-ojeda@kernel.org>
+
+From: Gary Guo <gary@garyguo.net>
+
+commit 1bae8729e50a900f41e9a1c17ae81113e4cf62b8 upstream.
+
+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>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ rust/ffi.rs | 37 ++++++++++++++++++++++++++++++++++++-
+ rust/kernel/error.rs | 5 +----
+ rust/kernel/firmware.rs | 2 +-
+ rust/kernel/uaccess.rs | 27 +++++++--------------------
+ 4 files changed, 45 insertions(+), 26 deletions(-)
+
+--- a/rust/ffi.rs
++++ b/rust/ffi.rs
+@@ -10,4 +10,39 @@
+
+ #![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;
+--- a/rust/kernel/error.rs
++++ b/rust/kernel/error.rs
+@@ -153,11 +153,8 @@ impl Error {
+
+ /// 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.
+--- a/rust/kernel/firmware.rs
++++ b/rust/kernel/firmware.rs
+@@ -12,7 +12,7 @@ use core::ptr::NonNull;
+ /// 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 {
+--- a/rust/kernel/uaccess.rs
++++ b/rust/kernel/uaccess.rs
+@@ -8,7 +8,7 @@ use crate::{
+ alloc::Flags,
+ bindings,
+ error::Result,
+- ffi::{c_ulong, c_void},
++ ffi::c_void,
+ prelude::*,
+ types::{AsBytes, FromBytes},
+ };
+@@ -224,13 +224,9 @@ impl UserSliceReader {
+ 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);
+ }
+@@ -259,9 +255,6 @@ impl UserSliceReader {
+ 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.
+ //
+@@ -272,7 +265,7 @@ impl UserSliceReader {
+ bindings::_copy_from_user(
+ out.as_mut_ptr().cast::<c_void>(),
+ self.ptr as *const c_void,
+- len_ulong,
++ len,
+ )
+ };
+ if res != 0 {
+@@ -335,12 +328,9 @@ impl UserSliceWriter {
+ 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);
+ }
+@@ -359,9 +349,6 @@ impl UserSliceWriter {
+ 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.
+ //
+@@ -372,7 +359,7 @@ impl UserSliceWriter {
+ 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 / kernel / stable-queue.git / commitdiff
