linux/common-config: Spell out the current set of supported Rust targets

This keeps us from accidentally running into platforms where Rust is not
supported by the Linux kernel itself (for that particular platform).

pkgs/os-specific/linux/kernel/common-config.nix

@@ -43,17 +43,24 @@ let
   );
 
   forceRust = features.rust or false;
-  kernelSupportsRust = lib.versionAtLeast version "6.7"
-    # Known to be broken: https://lore.kernel.org/lkml/31885EDD-EF6D-4EF1-94CA-276BA7A340B7@kernel.org/T/
-    && !(stdenv.hostPlatform.isRiscV && stdenv.cc.isGNU);
-
+  # Architecture support collected from HAVE_RUST Kconfig definitions and the following table:
+  # https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/rust/arch-support.rst
+  kernelSupportsRust = (
+    lib.versionAtLeast version "6.12"
+    && (
+      stdenv.hostPlatform.isx86_64
+      || stdenv.hostPlatform.isLoongArch64
+      || stdenv.hostPlatform.isAarch64
+      || (stdenv.hostPlatform.isRiscV64 && !stdenv.cc.isGNU)
+    )
+  );
 
   # Currently only enabling Rust by default on kernel 6.12+,
   # which actually has features that use Rust that we want.
   defaultRust = lib.versionAtLeast version "6.12" && rustAvailable;
   withRust =
     assert lib.assertMsg (!(forceRust && !kernelSupportsRust)) ''
-      Kernels below 6.7 (the kernel being built is ${version}) don't support Rust.
+      Kernel ${version} is not declared as supporting Rust on this host platform and compiler.
     '';
     (forceRust || defaultRust) && kernelSupportsRust;