Rust fixes for v6.14

Toolchain and infrastructure:
 
  - Do not export KASAN ODR symbols to avoid gendwarfksyms warnings.
 
  - Fix future Rust 1.86.0 (to be released 2025-04-03) x86_64 builds.
 
  - Clean future Rust 1.86.0 (to be released 2025-04-03) warning.
 
  - Fix future GCC 15 (to be released in a few months) builds.
 
  - Fix `rusttest` target in macOS.
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Merge tag 'rust-fixes-6.14' of https://github.com/Rust-for-Linux/linux

Pull rust fixes from Miguel Ojeda:

 - Do not export KASAN ODR symbols to avoid gendwarfksyms warnings

 - Fix future Rust 1.86.0 (to be released 2025-04-03) x86_64 builds

 - Clean future Rust 1.86.0 (to be released 2025-04-03) warning

 - Fix future GCC 15 (to be released in a few months) builds

 - Fix `rusttest` target in macOS

* tag 'rust-fixes-6.14' of https://github.com/Rust-for-Linux/linux:
  x86: rust: set rustc-abi=x86-softfloat on rustc>=1.86.0
  rust: kbuild: do not export generated KASAN ODR symbols
  rust: kbuild: add -fzero-init-padding-bits to bindgen_skip_cflags
  rust: init: use explicit ABI to clean warning in future compilers
  rust: kbuild: use host dylib naming in rusttestlib-kernel

rust/Makefile

@@ -144,7 +144,7 @@ rusttestlib-kernel: private rustc_target_flags = --extern ffi \
     --extern bindings --extern uapi
 rusttestlib-kernel: $(src)/kernel/lib.rs \
     rusttestlib-bindings rusttestlib-uapi rusttestlib-build_error \
-    $(obj)/libmacros.so $(obj)/bindings.o FORCE
+    $(obj)/$(libmacros_name) $(obj)/bindings.o FORCE
 	+$(call if_changed,rustc_test_library)
 
 rusttestlib-bindings: private rustc_target_flags = --extern ffi
@@ -240,6 +240,7 @@ bindgen_skip_c_flags := -mno-fp-ret-in-387 -mpreferred-stack-boundary=% \
 	-fzero-call-used-regs=% -fno-stack-clash-protection \
 	-fno-inline-functions-called-once -fsanitize=bounds-strict \
 	-fstrict-flex-arrays=% -fmin-function-alignment=% \
+	-fzero-init-padding-bits=% \
 	--param=% --param asan-%
 
 # Derived from `scripts/Makefile.clang`.
@@ -331,7 +332,7 @@ $(obj)/bindings/bindings_helpers_generated.rs: private bindgen_target_extra = ;
 $(obj)/bindings/bindings_helpers_generated.rs: $(src)/helpers/helpers.c FORCE
 	$(call if_changed_dep,bindgen)
 
-rust_exports = $(NM) -p --defined-only $(1) | awk '$$2~/(T|R|D|B)/ && $$3!~/__cfi/ { printf $(2),$$3 }'
+rust_exports = $(NM) -p --defined-only $(1) | awk '$$2~/(T|R|D|B)/ && $$3!~/__cfi/ && $$3!~/__odr_asan/ { printf $(2),$$3 }'
 
 quiet_cmd_exports = EXPORTS $@
       cmd_exports = \

rust/kernel/init.rs

@@ -870,7 +870,7 @@ pub unsafe trait PinInit<T: ?Sized, E = Infallible>: Sized {
     /// use kernel::{types::Opaque, init::pin_init_from_closure};
     /// #[repr(C)]
     /// struct RawFoo([u8; 16]);
-    /// extern {
+    /// extern "C" {
     ///     fn init_foo(_: *mut RawFoo);
     /// }
     ///

scripts/generate_rust_target.rs

@@ -165,6 +165,18 @@ impl KernelConfig {
         let option = "CONFIG_".to_owned() + option;
         self.0.contains_key(&option)
     }
+
+    /// Is the rustc version at least `major.minor.patch`?
+    fn rustc_version_atleast(&self, major: u32, minor: u32, patch: u32) -> bool {
+        let check_version = 100000 * major + 100 * minor + patch;
+        let actual_version = self
+            .0
+            .get("CONFIG_RUSTC_VERSION")
+            .unwrap()
+            .parse::<u32>()
+            .unwrap();
+        check_version <= actual_version
+    }
 }
 
 fn main() {
@@ -182,6 +194,9 @@ fn main() {
         }
     } else if cfg.has("X86_64") {
         ts.push("arch", "x86_64");
+        if cfg.rustc_version_atleast(1, 86, 0) {
+            ts.push("rustc-abi", "x86-softfloat");
+        }
         ts.push(
             "data-layout",
             "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128",
@@ -215,6 +230,9 @@ fn main() {
             panic!("32-bit x86 only works under UML");
         }
         ts.push("arch", "x86");
+        if cfg.rustc_version_atleast(1, 86, 0) {
+            ts.push("rustc-abi", "x86-softfloat");
+        }
         ts.push(
             "data-layout",
             "e-m:e-p:32:32-p270:32:32-p271:32:32-p272:64:64-i128:128-f64:32:64-f80:32-n8:16:32-S128",