From de4bf344b26f355b5d92071503f7a8fd18bc7f6b Mon Sep 17 00:00:00 2001
From: Lan Tian <xuyh0120@outlook.com>
Date: Sat, 9 May 2026 16:46:47 -0700
Subject: [PATCH] Keep Makefile patch for a few kmods that want gcc

---
 README.md                   | 10 ++++++++++
 helpers.nix                 | 24 ++++++++++++++++++++++++
 kernel-cachyos/packages.nix | 25 +++++++++++++++----------
 3 files changed, 49 insertions(+), 10 deletions(-)

diff --git a/README.md b/README.md
index 709d324..1e52990 100644
--- a/README.md
+++ b/README.md
@@ -365,6 +365,16 @@ Additional arguments are passed through to `buildLinux` from nixpkgs. See [nixpk
     # Additional args are available. See kernel-cachyos/mkCachyKernel.nix
   };
 
+  # For non-LTO kernels
   kernelPackages = pkgs.linuxKernel.packagesFor kernel;
+
+
+  # For LTO kernels, helpers.kernelModuleLLVMOverride fixes compilation for some
+  # out-of-tree modules in nixpkgs.
+  kernelPackagesWithLTOFix = let
+    # helpers.nix provides a few utilities for building kernel with LTO.
+    # I haven't figured out a clean way to expose it in flakes.
+    helpers = pkgs.callPackage "${inputs.nix-cachyos-kernel.outPath}/helpers.nix" {};
+  in helpers.kernelModuleLLVMOverride (pkgs.linuxKernel.packagesFor kernel);
 }
 ```
diff --git a/helpers.nix b/helpers.nix
index 049f522..a9cc26d 100644
--- a/helpers.nix
+++ b/helpers.nix
@@ -55,4 +55,28 @@ rec {
         pkgs.patchelf
       ];
     });
+
+  kernelModuleLLVMOverride =
+    kernelPackages_:
+    kernelPackages_.extend (
+      _final: prev:
+      lib.mapAttrs (
+        n: v:
+        if
+          builtins.elem "LLVM=1" kernelPackages_.kernel.commonMakeFlags
+          && !(builtins.elem n [ "kernel" ])
+          && lib.isDerivation v
+          && ((v.overrideAttrs or null) != null)
+        then
+          v.overrideAttrs (old: {
+            postPatch = (if (old.postPatch or null) == null then "" else old.postPatch) + ''
+              if [ -f Makefile ]; then
+                substituteInPlace Makefile --replace "gcc" "cc"
+              fi
+            '';
+          })
+        else
+          v
+      ) prev
+    );
 }
diff --git a/kernel-cachyos/packages.nix b/kernel-cachyos/packages.nix
index 0a3c65b..3e1905e 100644
--- a/kernel-cachyos/packages.nix
+++ b/kernel-cachyos/packages.nix
@@ -6,21 +6,26 @@
   ...
 }:
 let
+  helpers = callPackage ../helpers.nix { };
+  inherit (helpers) kernelModuleLLVMOverride;
+
   kernels = lib.filterAttrs (_: lib.isDerivation) (callPackage ./. { inherit inputs; });
 in
 lib.mapAttrs' (
   n: v:
   let
-    packages = (linuxKernel.packagesFor v).extend (
-      final: prev:
-      let
-        variant = lib.removePrefix "linux-cachyos-" v.cachyosConfigVariant;
-      in
-      {
-        zfs_cachyos = final.callPackage ../zfs-cachyos {
-          inherit inputs variant;
-        };
-      }
+    packages = kernelModuleLLVMOverride (
+      (linuxKernel.packagesFor v).extend (
+        final: prev:
+        let
+          variant = lib.removePrefix "linux-cachyos-" v.cachyosConfigVariant;
+        in
+        {
+          zfs_cachyos = final.callPackage ../zfs-cachyos {
+            inherit inputs variant;
+          };
+        }
+      )
     );
   in
   lib.nameValuePair "linuxPackages-${lib.removePrefix "linux-" n}" packages