rust: use feature(core_ffi_c) and feature(c_size_t) to replace c_types contents

This allows us to remove most of the contents we manually
maintained in `c_types`.

Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Author: ojeda

rust/kernel/c_types.rs

@@ -7,113 +7,4 @@
 //! C's standard integer types may differ in width depending on
 //! the architecture, thus we need to conditionally compile those.
 
-#![allow(non_camel_case_types)]
-
-#[cfg(any(target_arch = "arm", target_arch = "x86", target_arch = "riscv32",))]
-mod c {
-    /// C `void` type.
-    pub type c_void = core::ffi::c_void;
-
-    /// C `char` type.
-    pub type c_char = i8;
-
-    /// C `signed char` type.
-    pub type c_schar = i8;
-
-    /// C `unsigned char` type.
-    pub type c_uchar = u8;
-
-    /// C `short` type.
-    pub type c_short = i16;
-
-    /// C `unsigned short` type.
-    pub type c_ushort = u16;
-
-    /// C `int` type.
-    pub type c_int = i32;
-
-    /// C `unsigned int` type.
-    pub type c_uint = u32;
-
-    /// C `long` type.
-    pub type c_long = i32;
-
-    /// C `unsigned long` type.
-    pub type c_ulong = u32;
-
-    /// C `long long` type.
-    pub type c_longlong = i64;
-
-    /// C `unsigned long long` type.
-    pub type c_ulonglong = u64;
-
-    /// C `ssize_t` type (typically defined in `<sys/types.h>` by POSIX).
-    ///
-    /// For some 32-bit architectures like this one, the kernel defines it as
-    /// `int`, i.e. it is an [`i32`].
-    pub type c_ssize_t = isize;
-
-    /// C `size_t` type (typically defined in `<stddef.h>`).
-    ///
-    /// For some 32-bit architectures like this one, the kernel defines it as
-    /// `unsigned int`, i.e. it is an [`u32`].
-    pub type c_size_t = usize;
-}
-
-#[cfg(any(
-    target_arch = "aarch64",
-    target_arch = "x86_64",
-    target_arch = "powerpc64",
-    target_arch = "riscv64",
-))]
-mod c {
-    /// C `void` type.
-    pub type c_void = core::ffi::c_void;
-
-    /// C `char` type.
-    pub type c_char = i8;
-
-    /// C `signed char` type.
-    pub type c_schar = i8;
-
-    /// C `unsigned char` type.
-    pub type c_uchar = u8;
-
-    /// C `short` type.
-    pub type c_short = i16;
-
-    /// C `unsigned short` type.
-    pub type c_ushort = u16;
-
-    /// C `int` type.
-    pub type c_int = i32;
-
-    /// C `unsigned int` type.
-    pub type c_uint = u32;
-
-    /// C `long` type.
-    pub type c_long = i64;
-
-    /// C `unsigned long` type.
-    pub type c_ulong = u64;
-
-    /// C `long long` type.
-    pub type c_longlong = i64;
-
-    /// C `unsigned long long` type.
-    pub type c_ulonglong = u64;
-
-    /// C `ssize_t` type (typically defined in `<sys/types.h>` by POSIX).
-    ///
-    /// For 64-bit architectures like this one, the kernel defines it as
-    /// `long`, i.e. it is an [`i64`].
-    pub type c_ssize_t = isize;
-
-    /// C `size_t` type (typically defined in `<stddef.h>`).
-    ///
-    /// For 64-bit architectures like this one, the kernel defines it as
-    /// `unsigned long`, i.e. it is an [`u64`].
-    pub type c_size_t = usize;
-}
-
-pub use c::*;
+pub use core::ffi::*;

rust/kernel/lib.rs

@@ -19,6 +19,8 @@
 #![feature(const_ptr_offset_from)]
 #![feature(const_refs_to_cell)]
 #![feature(const_trait_impl)]
+#![feature(core_ffi_c)]
+#![feature(c_size_t)]
 #![feature(doc_cfg)]
 #![feature(generic_associated_types)]
 #![feature(ptr_metadata)]

scripts/Makefile.build

@@ -275,7 +275,7 @@ $(obj)/%.lst: $(src)/%.c FORCE
 # Compile Rust sources (.rs)
 # ---------------------------------------------------------------------------
 
-rust_allowed_features := allocator_api,bench_black_box,concat_idents,generic_associated_types
+rust_allowed_features := allocator_api,bench_black_box,concat_idents,core_ffi_c,generic_associated_types
 
 rust_common_cmd = \
 	RUST_MODFILE=$(modfile) $(RUSTC_OR_CLIPPY) $(rust_flags) \