Merge tag 'rust-fixes-6.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux

Pull rust fixes from Miguel Ojeda:

 - Two changes to prepare for the future Rust 1.91.0 release (expected
   2025-10-30, currently in nightly): a target specification format
   change and a renamed, soon-to-be-stabilized 'core' function.

* tag 'rust-fixes-6.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux:
  rust: support Rust >= 1.91.0 target spec
  rust: use the new name Location::file_as_c_str() in Rust >= 1.91.0

Author: torvalds

init/Kconfig

@@ -146,6 +146,9 @@ config RUSTC_HAS_UNNECESSARY_TRANSMUTES
 config RUSTC_HAS_FILE_WITH_NUL
 	def_bool RUSTC_VERSION >= 108900
 
+config RUSTC_HAS_FILE_AS_C_STR
+	def_bool RUSTC_VERSION >= 109100
+
 config PAHOLE_VERSION
 	int
 	default $(shell,$(srctree)/scripts/pahole-version.sh $(PAHOLE))

rust/kernel/lib.rs

@@ -296,7 +296,7 @@ macro_rules! asm {
 
 /// Gets the C string file name of a [`Location`].
 ///
-/// If `file_with_nul()` is not available, returns a string that warns about it.
+/// If `Location::file_as_c_str()` is not available, returns a string that warns about it.
 ///
 /// [`Location`]: core::panic::Location
 ///
@@ -310,8 +310,8 @@ macro_rules! asm {
 ///     let caller = core::panic::Location::caller();
 ///
 ///     // Output:
-///     // - A path like "rust/kernel/example.rs" if file_with_nul() is available.
-///     // - "<Location::file_with_nul() not supported>" otherwise.
+///     // - A path like "rust/kernel/example.rs" if `file_as_c_str()` is available.
+///     // - "<Location::file_as_c_str() not supported>" otherwise.
 ///     let caller_file = file_from_location(caller);
 ///
 ///     // Prints out the message with caller's file name.
@@ -326,14 +326,19 @@ macro_rules! asm {
 /// ```
 #[inline]
 pub fn file_from_location<'a>(loc: &'a core::panic::Location<'a>) -> &'a core::ffi::CStr {
-    #[cfg(CONFIG_RUSTC_HAS_FILE_WITH_NUL)]
+    #[cfg(CONFIG_RUSTC_HAS_FILE_AS_C_STR)]
+    {
+        loc.file_as_c_str()
+    }
+
+    #[cfg(all(CONFIG_RUSTC_HAS_FILE_WITH_NUL, not(CONFIG_RUSTC_HAS_FILE_AS_C_STR)))]
     {
         loc.file_with_nul()
     }
 
     #[cfg(not(CONFIG_RUSTC_HAS_FILE_WITH_NUL))]
     {
         let _ = loc;
-        c"<Location::file_with_nul() not supported>"
+        c"<Location::file_as_c_str() not supported>"
     }
 }

scripts/generate_rust_target.rs

@@ -225,7 +225,11 @@ fn main() {
         ts.push("features", features);
         ts.push("llvm-target", "x86_64-linux-gnu");
         ts.push("supported-sanitizers", ["kcfi", "kernel-address"]);
-        ts.push("target-pointer-width", "64");
+        if cfg.rustc_version_atleast(1, 91, 0) {
+            ts.push("target-pointer-width", 64);
+        } else {
+            ts.push("target-pointer-width", "64");
+        }
     } else if cfg.has("X86_32") {
         // This only works on UML, as i386 otherwise needs regparm support in rustc
         if !cfg.has("UML") {
@@ -245,7 +249,11 @@ fn main() {
         }
         ts.push("features", features);
         ts.push("llvm-target", "i386-unknown-linux-gnu");
-        ts.push("target-pointer-width", "32");
+        if cfg.rustc_version_atleast(1, 91, 0) {
+            ts.push("target-pointer-width", 32);
+        } else {
+            ts.push("target-pointer-width", "32");
+        }
     } else if cfg.has("LOONGARCH") {
         panic!("loongarch uses the builtin rustc loongarch64-unknown-none-softfloat target");
     } else {