Commit d072acda authored by Gary Guo's avatar Gary Guo Committed by Miguel Ojeda
Browse files

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.

Signed-off-by: default avatarGary Guo <gary@garyguo.net>
Link: https://lore.kernel.org/r/20240913213041.395655-4-gary@garyguo.net


[ Added `rustdoc`, `rusttest` and KUnit tests support. Rebased on top of
  `rust-next` (e.g. migrated more `core::ffi` cases). Reworded crate
  docs slightly and formatted. - Miguel ]
Signed-off-by: default avatarMiguel Ojeda <ojeda@kernel.org>
parent 2fd6f55c

rust/Makefile

+26 −13
Original line number Diff line number Diff line
@@ -3,7 +3,7 @@ 
# Where to place rustdoc generated documentation

rustdoc_output := $(objtree)/Documentation/output/rust/rustdoc



obj-$(CONFIG_RUST) += core.o compiler_builtins.o

obj-$(CONFIG_RUST) += core.o compiler_builtins.o ffi.o

always-$(CONFIG_RUST) += exports_core_generated.h



# Missing prototypes are expected in the helpers since these are exported
@@ -103,10 +103,13 @@ rustdoc-core: $(RUST_LIB_SRC)/core/src/lib.rs FORCE 
rustdoc-compiler_builtins: $(src)/compiler_builtins.rs rustdoc-core FORCE

	+$(call if_changed,rustdoc)



rustdoc-kernel: private rustc_target_flags = \

rustdoc-ffi: $(src)/ffi.rs rustdoc-core FORCE

	+$(call if_changed,rustdoc)



rustdoc-kernel: private rustc_target_flags = --extern ffi \

    --extern build_error --extern macros=$(objtree)/$(obj)/libmacros.so \

    --extern bindings --extern uapi

rustdoc-kernel: $(src)/kernel/lib.rs rustdoc-core rustdoc-macros \

rustdoc-kernel: $(src)/kernel/lib.rs rustdoc-core rustdoc-ffi rustdoc-macros \

    rustdoc-compiler_builtins $(obj)/libmacros.so \

    $(obj)/bindings.o FORCE

	+$(call if_changed,rustdoc)
@@ -124,12 +127,15 @@ quiet_cmd_rustc_test_library = RUSTC TL $< 
rusttestlib-build_error: $(src)/build_error.rs FORCE

	+$(call if_changed,rustc_test_library)



rusttestlib-ffi: $(src)/ffi.rs FORCE

	+$(call if_changed,rustc_test_library)



rusttestlib-macros: private rustc_target_flags = --extern proc_macro

rusttestlib-macros: private rustc_test_library_proc = yes

rusttestlib-macros: $(src)/macros/lib.rs FORCE

	+$(call if_changed,rustc_test_library)



rusttestlib-kernel: private rustc_target_flags = \

rusttestlib-kernel: private rustc_target_flags = --extern ffi \

    --extern build_error --extern macros \

    --extern bindings --extern uapi

rusttestlib-kernel: $(src)/kernel/lib.rs \
@@ -137,10 +143,12 @@ rusttestlib-kernel: $(src)/kernel/lib.rs \ 
    $(obj)/libmacros.so $(obj)/bindings.o FORCE

	+$(call if_changed,rustc_test_library)



rusttestlib-bindings: $(src)/bindings/lib.rs FORCE

rusttestlib-bindings: private rustc_target_flags = --extern ffi

rusttestlib-bindings: $(src)/bindings/lib.rs rusttestlib-ffi FORCE

	+$(call if_changed,rustc_test_library)



rusttestlib-uapi: $(src)/uapi/lib.rs FORCE

rusttestlib-uapi: private rustc_target_flags = --extern ffi

rusttestlib-uapi: $(src)/uapi/lib.rs rusttestlib-ffi FORCE

	+$(call if_changed,rustc_test_library)



quiet_cmd_rustdoc_test = RUSTDOC T $<
@@ -160,7 +168,7 @@ quiet_cmd_rustdoc_test_kernel = RUSTDOC TK $< 
	mkdir -p $(objtree)/$(obj)/test/doctests/kernel; \

	OBJTREE=$(abspath $(objtree)) \

	$(RUSTDOC) --test $(rust_flags) \

		-L$(objtree)/$(obj) --extern kernel \

		-L$(objtree)/$(obj) --extern ffi --extern kernel \

		--extern build_error --extern macros \

		--extern bindings --extern uapi \

		--no-run --crate-name kernel -Zunstable-options \
@@ -198,9 +206,9 @@ rusttest-macros: $(src)/macros/lib.rs \ 
	+$(call if_changed,rustc_test)

	+$(call if_changed,rustdoc_test)



rusttest-kernel: private rustc_target_flags = \

rusttest-kernel: private rustc_target_flags = --extern ffi \

    --extern build_error --extern macros --extern bindings --extern uapi

rusttest-kernel: $(src)/kernel/lib.rs rusttestlib-kernel \

rusttest-kernel: $(src)/kernel/lib.rs rusttestlib-ffi rusttestlib-kernel \

    rusttestlib-build_error rusttestlib-macros rusttestlib-bindings \

    rusttestlib-uapi FORCE

	+$(call if_changed,rustc_test)
@@ -273,7 +281,7 @@ bindgen_c_flags_final = $(bindgen_c_flags_lto) -fno-builtin -D__BINDGEN__ 
quiet_cmd_bindgen = BINDGEN $@

      cmd_bindgen = \

	$(BINDGEN) $< $(bindgen_target_flags) \

		--use-core --with-derive-default --ctypes-prefix core::ffi --no-layout-tests \

		--use-core --with-derive-default --ctypes-prefix ffi --no-layout-tests \

		--no-debug '.*' --enable-function-attribute-detection \

		-o $@ -- $(bindgen_c_flags_final) -DMODULE \

		$(bindgen_target_cflags) $(bindgen_target_extra)
@@ -401,18 +409,23 @@ $(obj)/compiler_builtins.o: $(src)/compiler_builtins.rs $(obj)/core.o FORCE 
$(obj)/build_error.o: $(src)/build_error.rs $(obj)/compiler_builtins.o FORCE

	+$(call if_changed_rule,rustc_library)



$(obj)/ffi.o: $(src)/ffi.rs $(obj)/compiler_builtins.o FORCE

	+$(call if_changed_rule,rustc_library)



$(obj)/bindings.o: private rustc_target_flags = --extern ffi

$(obj)/bindings.o: $(src)/bindings/lib.rs \

    $(obj)/compiler_builtins.o \

    $(obj)/ffi.o \

    $(obj)/bindings/bindings_generated.rs \

    $(obj)/bindings/bindings_helpers_generated.rs FORCE

	+$(call if_changed_rule,rustc_library)



$(obj)/uapi.o: private rustc_target_flags = --extern ffi

$(obj)/uapi.o: $(src)/uapi/lib.rs \

    $(obj)/compiler_builtins.o \

    $(obj)/ffi.o \

    $(obj)/uapi/uapi_generated.rs FORCE

	+$(call if_changed_rule,rustc_library)



$(obj)/kernel.o: private rustc_target_flags = \

$(obj)/kernel.o: private rustc_target_flags = --extern ffi \

    --extern build_error --extern macros --extern bindings --extern uapi

$(obj)/kernel.o: $(src)/kernel/lib.rs $(obj)/build_error.o \

    $(obj)/libmacros.so $(obj)/bindings.o $(obj)/uapi.o FORCE

rust/ffi.rs

0 → 100644
+13 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0



//! Foreign function interface (FFI) types.

//!

//! This crate provides mapping from C primitive types to Rust ones.

//!

//! The Rust [`core`] crate provides [`core::ffi`], which maps integer types to the platform default

//! C ABI. The kernel does not use [`core::ffi`], so it can customise the mapping that deviates from

//! the platform default.



#![no_std]



pub use core::ffi::*;

rust/kernel/alloc/allocator.rs

+1 −1
Original line number Diff line number Diff line
@@ -58,7 +58,7 @@ fn aligned_size(new_layout: Layout) -> usize { 
///

/// One of the following: `krealloc`, `vrealloc`, `kvrealloc`.

struct ReallocFunc(

    unsafe extern "C" fn(*const core::ffi::c_void, usize, u32) -> *mut core::ffi::c_void,

    unsafe extern "C" fn(*const crate::ffi::c_void, usize, u32) -> *mut crate::ffi::c_void,

);



impl ReallocFunc {

rust/kernel/alloc/allocator_test.rs

+2 −2
Original line number Diff line number Diff line
@@ -24,10 +24,10 @@ 


extern "C" {

    #[link_name = "aligned_alloc"]

    fn libc_aligned_alloc(align: usize, size: usize) -> *mut core::ffi::c_void;

    fn libc_aligned_alloc(align: usize, size: usize) -> *mut crate::ffi::c_void;



    #[link_name = "free"]

    fn libc_free(ptr: *mut core::ffi::c_void);

    fn libc_free(ptr: *mut crate::ffi::c_void);

}



// SAFETY:

rust/kernel/alloc/kbox.rs

+6 −6
Original line number Diff line number Diff line
@@ -355,17 +355,17 @@ impl<T: 'static, A> ForeignOwnable for Box<T, A> 
{

    type Borrowed<'a> = &'a T;



    fn into_foreign(self) -> *const core::ffi::c_void {

    fn into_foreign(self) -> *const crate::ffi::c_void {

        Box::into_raw(self) as _

    }



    unsafe fn from_foreign(ptr: *const core::ffi::c_void) -> Self {

    unsafe fn from_foreign(ptr: *const crate::ffi::c_void) -> Self {

        // SAFETY: The safety requirements of this function ensure that `ptr` comes from a previous

        // call to `Self::into_foreign`.

        unsafe { Box::from_raw(ptr as _) }

    }



    unsafe fn borrow<'a>(ptr: *const core::ffi::c_void) -> &'a T {

    unsafe fn borrow<'a>(ptr: *const crate::ffi::c_void) -> &'a T {

        // SAFETY: The safety requirements of this method ensure that the object remains alive and

        // immutable for the duration of 'a.

        unsafe { &*ptr.cast() }
@@ -378,18 +378,18 @@ impl<T: 'static, A> ForeignOwnable for Pin<Box<T, A>> 
{

    type Borrowed<'a> = Pin<&'a T>;



    fn into_foreign(self) -> *const core::ffi::c_void {

    fn into_foreign(self) -> *const crate::ffi::c_void {

        // SAFETY: We are still treating the box as pinned.

        Box::into_raw(unsafe { Pin::into_inner_unchecked(self) }) as _

    }



    unsafe fn from_foreign(ptr: *const core::ffi::c_void) -> Self {

    unsafe fn from_foreign(ptr: *const crate::ffi::c_void) -> Self {

        // SAFETY: The safety requirements of this function ensure that `ptr` comes from a previous

        // call to `Self::into_foreign`.

        unsafe { Pin::new_unchecked(Box::from_raw(ptr as _)) }

    }



    unsafe fn borrow<'a>(ptr: *const core::ffi::c_void) -> Pin<&'a T> {

    unsafe fn borrow<'a>(ptr: *const crate::ffi::c_void) -> Pin<&'a T> {

        // SAFETY: The safety requirements for this function ensure that the object is still alive,

        // so it is safe to dereference the raw pointer.

        // The safety requirements of `from_foreign` also ensure that the object remains alive for