Refactor to allow overriding for customizing kernel

README.md

@@ -109,7 +109,7 @@ If you want to construct your own `linuxPackages` attrset with `linuxKernel.pack
         { pkgs, ... }:
         {
           nixpkgs.overlays = [ self.overlay ];
-          boot.kernelPackages = pkgs.cachyosKernels.linuxPackages-cachyos-latest;
+          boot.kernelPackages = pkgs.linuxKernel.packagesFor pkgs.cachyosKernels.linux-cachyos-latest;
 
           # ZFS config
           boot.supportedFilesystems.zfs = true;
@@ -124,3 +124,31 @@ If you want to construct your own `linuxPackages` attrset with `linuxKernel.pack
   };
 }
 ```
+
+## How to apply CachyOS patches on your own kernel
+
+The kernels provided in this flake can be overridden to use your own kernel source. This is helpful if you want to use a kernel version not available in Nixpkgs.
+
+```nix
+{
+  kernel = pkgs.cachyosKernels.linux-cachyos-latest.override {
+    pname = "linux-cachyos-with-custom-source";
+    version = "6.12.34";
+    src = pkgs.fetchurl {
+      # ...
+    };
+    # Additional args are available. See kernel-cachyos/mkCachyKernel.nix
+  };
+
+  # For non-LTO kernels
+  kernelPackages = pkgs.linuxKernel.packagesFor kernel;
+
+  # 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" {};
+
+  # For LTO kernels, helpers.kernelModuleLLVMOverride fixes compilation for some
+  # out-of-tree modules in nixpkgs.
+  kernelPackagesWithLTOFix = helpers.kernelModuleLLVMOverride (pkgs.linuxKernel.packagesFor kernel);
+}
+```

flake.nix

@@ -28,17 +28,21 @@
         loadPackages =
           pkgs:
           let
-            kernels =
+            load =
+              path:
               lib.removeAttrs
-                (pkgs.callPackage ./kernel-cachyos {
+                (pkgs.callPackage path {
                   inherit inputs;
                 })
                 [
                   "override"
                   "overrideDerivation"
                 ];
+            kernels = load ./kernel-cachyos;
+            packages = load ./kernel-cachyos/packages.nix;
           in
           kernels
+          // packages
           // {
             zfs-cachyos = pkgs.callPackage ./zfs-cachyos {
               inherit inputs;

helpers.nix

@@ -77,5 +77,4 @@ rec {
           v
       ) prev
     );
-
 }

kernel-cachyos/default.nix

@@ -8,39 +8,32 @@
 }:
 let
   mkCachyKernel = callPackage ./mkCachyKernel.nix { inherit inputs; };
-
+in
-  batch =
+builtins.listToAttrs (
-    {
+  builtins.map (v: lib.nameValuePair v.pname v) [
-      pnameSuffix,
+    (mkCachyKernel {
-      version,
+      pname = "linux-cachyos-latest";
-      src,
-      configVariant,
-      ...
-    }:
-    [
-      (mkCachyKernel {
-        pnameSuffix = "${pnameSuffix}";
-        inherit version src configVariant;
-        lto = false;
-      })
-      (mkCachyKernel {
-        pnameSuffix = "${pnameSuffix}-lto";
-        inherit version src configVariant;
-        lto = true;
-      })
-    ];
-
-  batches = [
-    (batch {
-      pnameSuffix = "latest";
       inherit (linux_latest) version src;
       configVariant = "linux-cachyos";
+      lto = false;
     })
-    (batch {
+    (mkCachyKernel {
-      pnameSuffix = "lts";
+      pname = "linux-cachyos-latest-lto";
+      inherit (linux_latest) version src;
+      configVariant = "linux-cachyos";
+      lto = true;
+    })
+    (mkCachyKernel {
+      pname = "linux-cachyos-lts";
       inherit (linux) version src;
       configVariant = "linux-cachyos-lts";
+      lto = false;
     })
-  ];
+    (mkCachyKernel {
-in
+      pname = "linux-cachyos-lts-lto";
-builtins.listToAttrs (lib.flatten batches)
+      inherit (linux) version src;
+      configVariant = "linux-cachyos-lts";
+      lto = true;
+    })
+  ]
+)

kernel-cachyos/mkCachyKernel.nix

@@ -5,102 +5,120 @@
   buildLinux,
   stdenv,
   kernelPatches,
-  linuxKernel,
   ...
 }:
-{
+lib.makeOverridable (
-  pnameSuffix,
+  {
-  version,
+    pname,
-  src,
+    version,
-  configVariant,
+    src,
-  lto,
-}:
-let
-  helpers = callPackage ../helpers.nix { };
-  inherit (helpers) stdenvLLVM ltoMakeflags kernelModuleLLVMOverride;
 
-  splitted = lib.splitString "-" version;
+    # Kernel config variant to be used as defconfig, e.g. "linux-cachyos-lts".
-  ver0 = builtins.elemAt splitted 0;
+    # See https://github.com/CachyOS/linux-cachyos for available values.
-  major = lib.versions.pad 2 ver0;
+    configVariant,
 
-  cachyosConfigFile = "${inputs.cachyos-kernel.outPath}/${configVariant}/config";
+    # Set to true to enable Clang+ThinLTO.
+    lto,
 
-  # buildLinux doesn't accept postPatch, so adding config file early here
+    # Patches to be applied in patchedSrc phase. This is different from buildLinux's kernelPatches.
-  patchedSrc = stdenv.mkDerivation {
+    prePatch ? "",
-    pname = "linux-cachyos-${pnameSuffix}-src";
+    patches ? [ ],
-    inherit version src;
+    postPatch ? "",
-    patches = [
-      kernelPatches.bridge_stp_helper.patch
-      kernelPatches.request_key_helper.patch
-      "${inputs.cachyos-kernel-patches.outPath}/${major}/all/0001-cachyos-base-all.patch"
-    ];
-    postPatch = ''
-      for DIR in arch/*/configs; do
-        install -Dm644 ${cachyosConfigFile} $DIR/cachyos_defconfig
-      done
-    '';
-    dontConfigure = true;
-    dontBuild = true;
-    dontFixup = true;
-    installPhase = ''
-      mkdir -p $out
-      cp -r * $out/
-    '';
-  };
 
-  kernelPackage = buildLinux {
+    # See nixpkgs/pkgs/os-specific/linux/kernel/generic.nix for additional options.
-    pname = "linux-cachyos-${pnameSuffix}";
+    # Additional args are passed to buildLinux.
-    inherit version;
+    ...
-    src = patchedSrc;
+  }@args:
-    stdenv = if lto then stdenvLLVM else stdenv;
+  let
+    helpers = callPackage ../helpers.nix { };
+    inherit (helpers) stdenvLLVM ltoMakeflags;
 
-    extraMakeFlags = lib.optionals lto ltoMakeflags;
+    splitted = lib.splitString "-" version;
+    ver0 = builtins.elemAt splitted 0;
+    major = lib.versions.pad 2 ver0;
 
-    defconfig = "cachyos_defconfig";
+    cachyosConfigFile = "${inputs.cachyos-kernel.outPath}/${configVariant}/config";
+    cachyosPatch = "${inputs.cachyos-kernel-patches.outPath}/${major}/all/0001-cachyos-base-all.patch";
 
-    # Clang has some incompatibilities with NixOS's default kernel config
+    # buildLinux doesn't accept postPatch, so adding config file early here
-    ignoreConfigErrors = lto;
+    patchedSrc = stdenv.mkDerivation {
-
+      pname = "${pname}-src";
-    structuredExtraConfig =
+      inherit version src prePatch;
-      with lib.kernel;
+      patches = [
-      (
+        kernelPatches.bridge_stp_helper.patch
-        {
+        kernelPatches.request_key_helper.patch
-          NR_CPUS = lib.mkForce (option (freeform "8192"));
+        cachyosPatch
-
+      ]
-          # Follow NixOS default config to not break etc overlay
+      ++ patches;
-          OVERLAY_FS = module;
+      postPatch = ''
-          OVERLAY_FS_REDIRECT_DIR = no;
+        for DIR in arch/*/configs; do
-          OVERLAY_FS_REDIRECT_ALWAYS_FOLLOW = yes;
+          install -Dm644 ${cachyosConfigFile} $DIR/cachyos_defconfig
-          OVERLAY_FS_INDEX = no;
+        done
-          OVERLAY_FS_XINO_AUTO = no;
+      ''
-          OVERLAY_FS_METACOPY = no;
+      + postPatch;
-          OVERLAY_FS_DEBUG = no;
+      dontConfigure = true;
-        }
+      dontBuild = true;
-        // lib.optionalAttrs lto {
+      dontFixup = true;
-          LTO_NONE = no;
+      installPhase = ''
-          LTO_CLANG_THIN = yes;
+        mkdir -p $out
-        }
+        cp -r * $out/
-      );
+      '';
-
-    extraMeta = {
-      description = "Linux CachyOS Kernel" + lib.optionalString lto " with Clang+ThinLTO";
     };
-  };
+  in
+  buildLinux (
+    (lib.removeAttrs args [
+      "pname"
+      "version"
+      "src"
+      "configVariant"
+      "lto"
+      "prePatch"
+      "patches"
+      "postPatch"
+    ])
+    // {
+      inherit pname version;
+      src = patchedSrc;
+      stdenv = args.stdenv or (if lto then stdenvLLVM else stdenv);
 
-  zfsPackage = callPackage ../zfs-cachyos {
+      extraMakeFlags = (lib.optionals lto ltoMakeflags) ++ (args.extraMakeFlags or [ ]);
-    inherit inputs;
+
-    kernel = kernelPackage;
+      defconfig = args.defconfig or "cachyos_defconfig";
-  };
+
-in
+      # Clang has some incompatibilities with NixOS's default kernel config
-[
+      ignoreConfigErrors = args.ignoreConfigErrors or lto;
-  (lib.nameValuePair "linux-cachyos-${pnameSuffix}" kernelPackage)
+
-  (lib.nameValuePair "linuxPackages-cachyos-${pnameSuffix}" (
+      structuredExtraConfig =
-    kernelModuleLLVMOverride (
+        with lib.kernel;
-      (linuxKernel.packagesFor kernelPackage).extend (
+        (
-        final: prev: {
+          {
-          zfs_cachyos = zfsPackage;
+            NR_CPUS = lib.mkForce (option (freeform "8192"));
-        }
+
-      )
+            # Follow NixOS default config to not break etc overlay
-    )
+            OVERLAY_FS = module;
-  ))
+            OVERLAY_FS_REDIRECT_DIR = no;
-]
+            OVERLAY_FS_REDIRECT_ALWAYS_FOLLOW = yes;
+            OVERLAY_FS_INDEX = no;
+            OVERLAY_FS_XINO_AUTO = no;
+            OVERLAY_FS_METACOPY = no;
+            OVERLAY_FS_DEBUG = no;
+          }
+          // (lib.optionalAttrs lto {
+            LTO_NONE = no;
+            LTO_CLANG_THIN = yes;
+          })
+          // (args.structuredExtraConfig or { })
+        );
+
+      extraMeta = {
+        description = "Linux CachyOS Kernel" + lib.optionalString lto " with Clang+ThinLTO";
+      }
+      // (args.extraMeta or { });
+
+      extraPassthru = {
+        inherit cachyosConfigFile cachyosPatch;
+      }
+      // (args.extraPassthru or { });
+    }
+  )
+)

kernel-cachyos/packages.nix

@@ -1,14 +1,31 @@
 {
-  mode ? null,
+  inputs,
   callPackage,
   lib,
   linuxKernel,
-  sources,
   ...
 }:
 let
-  kernels = callPackage ./default.nix { inherit mode sources; };
+  helpers = callPackage ../helpers.nix { };
+  inherit (helpers) kernelModuleLLVMOverride;
+
+  kernels = lib.filterAttrs (_: lib.isDerivation) (callPackage ./. { inherit inputs; });
 in
-lib.mapAttrs (n: v: linuxKernel.packagesFor v) (
+lib.mapAttrs' (
-  lib.filterAttrs (n: nv: !lib.hasSuffix "configfile" n) kernels
+  n: v:
-)
+  let
+    zfsPackage = callPackage ../zfs-cachyos {
+      inherit inputs;
+      kernel = v;
+    };
+
+    packages = kernelModuleLLVMOverride (
+      (linuxKernel.packagesFor v).extend (
+        final: prev: {
+          zfs_cachyos = zfsPackage;
+        }
+      )
+    );
+  in
+  lib.nameValuePair "linuxPackages-${lib.removePrefix "linux-" n}" packages
+) kernels