rust: use absolute paths in macros referencing core and kernel

Macros and auto-generated code should use absolute paths, `::core::...`
and `::kernel::...`, for core and kernel references.

This prevents issues where user-defined modules named `core` or `kernel`
could be picked up instead of the `core` or `kernel` crates.

Thus clean some references up.

Suggested-by: Benno Lossin <benno.lossin@proton.me>
Closes: https://github.com/Rust-for-Linux/linux/issues/1150
Signed-off-by: Igor Korotin <igor.korotin.linux@gmail.com>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20250519164615.3310844-1-igor.korotin.linux@gmail.com
[ Applied `rustfmt`. Reworded slightly. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

3 files changed, 30 insertions, 29 deletions

diff --git a/rust/macros/kunit.rs b/rust/macros/kunit.rs
index 99ccac82edde..b146c5894e92 100644
--- a/rust/macros/kunit.rs
+++ b/rust/macros/kunit.rs
@@ -85,28 +85,28 @@ pub(crate) fn kunit_tests(attr: TokenStream, ts: TokenStream) -> TokenStream {
     // Looks like:
     //
     // ```
-    // unsafe extern "C" fn kunit_rust_wrapper_foo(_test: *mut kernel::bindings::kunit) { foo(); }
-    // unsafe extern "C" fn kunit_rust_wrapper_bar(_test: *mut kernel::bindings::kunit) { bar(); }
+    // unsafe extern "C" fn kunit_rust_wrapper_foo(_test: *mut ::kernel::bindings::kunit) { foo(); }
+    // unsafe extern "C" fn kunit_rust_wrapper_bar(_test: *mut ::kernel::bindings::kunit) { bar(); }
     //
-    // static mut TEST_CASES: [kernel::bindings::kunit_case; 3] = [
-    //     kernel::kunit::kunit_case(kernel::c_str!("foo"), kunit_rust_wrapper_foo),
-    //     kernel::kunit::kunit_case(kernel::c_str!("bar"), kunit_rust_wrapper_bar),
-    //     kernel::kunit::kunit_case_null(),
+    // static mut TEST_CASES: [::kernel::bindings::kunit_case; 3] = [
+    //     ::kernel::kunit::kunit_case(::kernel::c_str!("foo"), kunit_rust_wrapper_foo),
+    //     ::kernel::kunit::kunit_case(::kernel::c_str!("bar"), kunit_rust_wrapper_bar),
+    //     ::kernel::kunit::kunit_case_null(),
     // ];
     //
-    // kernel::kunit_unsafe_test_suite!(kunit_test_suit_name, TEST_CASES);
+    // ::kernel::kunit_unsafe_test_suite!(kunit_test_suit_name, TEST_CASES);
     // ```
     let mut kunit_macros = "".to_owned();
     let mut test_cases = "".to_owned();
     for test in &tests {
         let kunit_wrapper_fn_name = format!("kunit_rust_wrapper_{test}");
         let kunit_wrapper = format!(
-            "unsafe extern \"C\" fn {kunit_wrapper_fn_name}(_test: *mut kernel::bindings::kunit) {{ {test}(); }}"
+            "unsafe extern \"C\" fn {kunit_wrapper_fn_name}(_test: *mut ::kernel::bindings::kunit) {{ {test}(); }}"
         );
         writeln!(kunit_macros, "{kunit_wrapper}").unwrap();
         writeln!(
             test_cases,
-            "    kernel::kunit::kunit_case(kernel::c_str!(\"{test}\"), {kunit_wrapper_fn_name}),"
+            "    ::kernel::kunit::kunit_case(::kernel::c_str!(\"{test}\"), {kunit_wrapper_fn_name}),"
         )
         .unwrap();
     }
@@ -114,14 +114,14 @@ pub(crate) fn kunit_tests(attr: TokenStream, ts: TokenStream) -> TokenStream {
     writeln!(kunit_macros).unwrap();
     writeln!(
         kunit_macros,
-        "static mut TEST_CASES: [kernel::bindings::kunit_case; {}] = [\n{test_cases}    kernel::kunit::kunit_case_null(),\n];",
+        "static mut TEST_CASES: [::kernel::bindings::kunit_case; {}] = [\n{test_cases}    ::kernel::kunit::kunit_case_null(),\n];",
         tests.len() + 1
     )
     .unwrap();
 
     writeln!(
         kunit_macros,
-        "kernel::kunit_unsafe_test_suite!({attr}, TEST_CASES);"
+        "::kernel::kunit_unsafe_test_suite!({attr}, TEST_CASES);"
     )
     .unwrap();
 
diff --git a/rust/macros/lib.rs b/rust/macros/lib.rs
index 9acaa68c974e..cb429eceff71 100644
--- a/rust/macros/lib.rs
+++ b/rust/macros/lib.rs
@@ -283,7 +283,7 @@ pub fn concat_idents(ts: TokenStream) -> TokenStream {
 /// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14;
 /// macro_rules! pub_no_prefix {
 ///     ($prefix:ident, $($newname:ident),+) => {
-///         kernel::macros::paste! {
+///         ::kernel::macros::paste! {
 ///             $(pub(crate) const $newname: u32 = [<$prefix $newname>];)+
 ///         }
 ///     };
@@ -340,7 +340,7 @@ pub fn concat_idents(ts: TokenStream) -> TokenStream {
 /// # const binder_driver_return_protocol_BR_FAILED_REPLY: u32 = 14;
 /// macro_rules! pub_no_prefix {
 ///     ($prefix:ident, $($newname:ident),+) => {
-///         kernel::macros::paste! {
+///         ::kernel::macros::paste! {
 ///             $(pub(crate) const fn [<$newname:lower:span>]() -> u32 { [<$prefix $newname:span>] })+
 ///         }
 ///     };
@@ -375,7 +375,7 @@ pub fn concat_idents(ts: TokenStream) -> TokenStream {
 /// ```
 /// macro_rules! create_numbered_fn {
 ///     ($name:literal, $val:literal) => {
-///         kernel::macros::paste! {
+///         ::kernel::macros::paste! {
 ///             fn [<some_ $name _fn $val>]() -> u32 { $val }
 ///         }
 ///     };
diff --git a/rust/macros/module.rs b/rust/macros/module.rs
index 44e5cb108cea..de9304498a97 100644
--- a/rust/macros/module.rs
+++ b/rust/macros/module.rs
@@ -215,24 +215,24 @@ pub(crate) fn module(ts: TokenStream) -> TokenStream {
             // SAFETY: `__this_module` is constructed by the kernel at load time and will not be
             // freed until the module is unloaded.
             #[cfg(MODULE)]
-            static THIS_MODULE: kernel::ThisModule = unsafe {{
+            static THIS_MODULE: ::kernel::ThisModule = unsafe {{
                 extern \"C\" {{
-                    static __this_module: kernel::types::Opaque<kernel::bindings::module>;
+                    static __this_module: ::kernel::types::Opaque<::kernel::bindings::module>;
                 }}
 
-                kernel::ThisModule::from_ptr(__this_module.get())
+                ::kernel::ThisModule::from_ptr(__this_module.get())
             }};
             #[cfg(not(MODULE))]
-            static THIS_MODULE: kernel::ThisModule = unsafe {{
-                kernel::ThisModule::from_ptr(core::ptr::null_mut())
+            static THIS_MODULE: ::kernel::ThisModule = unsafe {{
+                ::kernel::ThisModule::from_ptr(::core::ptr::null_mut())
             }};
 
             /// The `LocalModule` type is the type of the module created by `module!`,
             /// `module_pci_driver!`, `module_platform_driver!`, etc.
             type LocalModule = {type_};
 
-            impl kernel::ModuleMetadata for {type_} {{
-                const NAME: &'static kernel::str::CStr = kernel::c_str!(\"{name}\");
+            impl ::kernel::ModuleMetadata for {type_} {{
+                const NAME: &'static ::kernel::str::CStr = ::kernel::c_str!(\"{name}\");
             }}
 
             // Double nested modules, since then nobody can access the public items inside.
@@ -250,8 +250,8 @@ pub(crate) fn module(ts: TokenStream) -> TokenStream {
                     #[used]
                     static __IS_RUST_MODULE: () = ();
 
-                    static mut __MOD: core::mem::MaybeUninit<{type_}> =
-                        core::mem::MaybeUninit::uninit();
+                    static mut __MOD: ::core::mem::MaybeUninit<{type_}> =
+                        ::core::mem::MaybeUninit::uninit();
 
                     // Loadable modules need to export the `{{init,cleanup}}_module` identifiers.
                     /// # Safety
@@ -262,7 +262,7 @@ pub(crate) fn module(ts: TokenStream) -> TokenStream {
                     #[doc(hidden)]
                     #[no_mangle]
                     #[link_section = \".init.text\"]
-                    pub unsafe extern \"C\" fn init_module() -> kernel::ffi::c_int {{
+                    pub unsafe extern \"C\" fn init_module() -> ::kernel::ffi::c_int {{
                         // SAFETY: This function is inaccessible to the outside due to the double
                         // module wrapping it. It is called exactly once by the C side via its
                         // unique name.
@@ -302,11 +302,12 @@ pub(crate) fn module(ts: TokenStream) -> TokenStream {
                     #[doc(hidden)]
                     #[link_section = \"{initcall_section}\"]
                     #[used]
-                    pub static __{name}_initcall: extern \"C\" fn() -> kernel::ffi::c_int = __{name}_init;
+                    pub static __{name}_initcall: extern \"C\" fn() -> ::kernel::ffi::c_int =
+                        __{name}_init;
 
                     #[cfg(not(MODULE))]
                     #[cfg(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS)]
-                    core::arch::global_asm!(
+                    ::core::arch::global_asm!(
                         r#\".section \"{initcall_section}\", \"a\"
                         __{name}_initcall:
                             .long   __{name}_init - .
@@ -317,7 +318,7 @@ pub(crate) fn module(ts: TokenStream) -> TokenStream {
                     #[cfg(not(MODULE))]
                     #[doc(hidden)]
                     #[no_mangle]
-                    pub extern \"C\" fn __{name}_init() -> kernel::ffi::c_int {{
+                    pub extern \"C\" fn __{name}_init() -> ::kernel::ffi::c_int {{
                         // SAFETY: This function is inaccessible to the outside due to the double
                         // module wrapping it. It is called exactly once by the C side via its
                         // placement above in the initcall section.
@@ -340,9 +341,9 @@ pub(crate) fn module(ts: TokenStream) -> TokenStream {
                     /// # Safety
                     ///
                     /// This function must only be called once.
-                    unsafe fn __init() -> kernel::ffi::c_int {{
+                    unsafe fn __init() -> ::kernel::ffi::c_int {{
                         let initer =
-                            <{type_} as kernel::InPlaceModule>::init(&super::super::THIS_MODULE);
+                            <{type_} as ::kernel::InPlaceModule>::init(&super::super::THIS_MODULE);
                         // SAFETY: No data race, since `__MOD` can only be accessed by this module
                         // and there only `__init` and `__exit` access it. These functions are only
                         // called once and `__exit` cannot be called before or during `__init`.