modularizing kernel and loader settings

system/modules/boot/kernel/default.nix

@@ -0,0 +1,72 @@
+# kernel.nix
+{
+  pkgs,
+  lib,
+  config,
+  ...
+}: let
+  inherit (lib) mkOption;
+  cfg = config.modules.boot.kernel;
+in {
+  options = {
+    modules.boot.kernel = {
+      variant = mkOption {
+        type = lib.types.enum ["latest" "cachyos"];
+        default = "latest";
+        description = "Kernel variant to use.";
+      };
+
+      hardware = mkOption {
+        type = lib.types.enum ["amd" "nvidia"];
+        default = "amd";
+        description = "Hardware type (GPU) configuration.";
+      };
+
+      extraKernelParams = mkOption {
+        type = lib.types.listOf lib.types.str;
+        default = [];
+        description = "Additional kernel parameters.";
+      };
+
+      extraBlacklistedModules = mkOption {
+        type = lib.types.listOf lib.types.str;
+        default = [];
+        description = "Additional kernel modules to blacklist.";
+      };
+    };
+  };
+
+  config = {
+    boot = {
+      consoleLogLevel = 3;
+
+      kernelPackages = (
+        if cfg.variant == "latest"
+        then pkgs.linuxPackages_latest
+        else if cfg.variant == "cachyos"
+        then pkgs.linuxPackages_cachyos
+        else pkgs.linuxPackages
+      );
+
+      kernelParams =
+        [
+          "quiet"
+          "splash"
+        ]
+        ++ (
+          if cfg.hardware == "amd"
+          then ["amd_pstate=active"]
+          else []
+        )
+        ++ cfg.extraKernelParams;
+
+      blacklistedKernelModules =
+        (
+          if cfg.hardware == "nvidia"
+          then ["nouveau"]
+          else []
+        )
+        ++ cfg.extraBlacklistedModules;
+    };
+  };
+}