boot config

modules/nixos/boot/default.nix

@@ -1,5 +1,7 @@
 {
   imports = [
     ./loader
+    ./generic.nix
+    ./plymouth.nix
   ];
 }

modules/nixos/boot/generic.nix

@@ -0,0 +1,160 @@
+{
+  pkgs,
+  config,
+  lib,
+  ...
+}: let
+  inherit (lib.modules) mkIf mkForce mkMerge mkDefault;
+  inherit (lib.lists) optionals;
+  inherit (lib.options) mkOption mkEnableOption;
+  inherit (lib.types) raw;
+
+  cfg = config.olympus.system.boot;
+in {
+  options.olympus.system.boot = {
+    enableKernelTweaks = mkEnableOption "security and performance related kernel parameters";
+    recommendedLoaderConfig = mkEnableOption "tweaks for common bootloader configs per my liking";
+    loadRecommendedModules = mkEnableOption "kernel modules that accommodate for most use cases";
+
+    kernel = mkOption {
+      type = raw;
+      default = pkgs.linuxPackages_cachyos;
+      description = "The kernel to use for the system";
+    };
+
+    initrd = {
+      enableTweaks = mkEnableOption "quality of life tweaks for the initrd stage";
+      optimizeCompressor = mkEnableOption ''
+        initrd compression algorithm optimizations for size.
+        Enabling this option will force initrd to use zstd (default) with
+        level 19 and -T0 (STDIN). This will reduce the initrd size greatly
+        at the cost of compression speed.
+        Not recommended for low-end hardware.
+      '';
+    };
+
+    silentBoot =
+      mkEnableOption ''
+        almost entirely silent boot process through `quiet` kernel parameter
+      ''
+      // {
+        default = cfg.plymouth.enable;
+      };
+  };
+
+  config = {
+    boot = {
+      consoleLogLevel = 3;
+
+      kernelPackages = mkDefault cfg.kernel;
+
+      loader = {
+        # if set to 0, space needs to be held to get the boot menu to appear
+        timeout = mkForce 2;
+
+        # copy boot files to /boot so that /nix/store is not required to boot
+        # it takes up more space but it makes my messups a bit safer
+        generationsDir.copyKernels = true;
+
+        # we need to allow installation to modify EFI variables
+        efi.canTouchEfiVariables = true;
+      };
+
+      # increase the map count, this is important for applications that require a lot of memory mappings
+      # such as games and emulators
+      kernel.sysctl."vm.max_map_count" = 2147483642;
+
+      initrd = mkMerge [
+        (mkIf cfg.initrd.enableTweaks {
+          # Verbosity of the initrd
+          # disabling verbosity removes only the mandatory messages generated by the NixOS
+          verbose = false;
+
+          systemd = {
+            # enable systemd in initrd (experimental)
+            enable = true;
+
+            # strip copied binaries and libraries from inframs
+            # saves some nice space
+            strip = true;
+          };
+
+          kernelModules = [
+            "nvme"
+            "xhci_pci"
+            "ahci"
+            "btrfs"
+            "sd_mod"
+            "dm_mod"
+          ];
+
+          availableKernelModules = [
+            "vmd"
+            "usbhid"
+            "sd_mod"
+            "sr_mod"
+            "dm_mod"
+            "uas"
+            "usb_storage"
+            "ata_piix"
+            "virtio_pci"
+            "virtio_scsi"
+            "ehci_pci"
+          ];
+        })
+
+        (mkIf cfg.initrd.optimizeCompressor {
+          compressor = "zstd";
+          compressorArgs = [
+            "-19"
+            "-T0"
+          ];
+        })
+      ];
+
+      # https://www.kernel.org/doc/html/latest/admin-guide/kernel-parameters.html
+      kernelParams =
+        optionals cfg.enableKernelTweaks [
+          # https://en.wikipedia.org/wiki/Kernel_page-table_isolation
+          # auto means kernel will automatically decide the pti state
+          "pti=auto" # on || off
+
+          # enable IOMMU for devices used in passthrough and provide better host performance
+          "iommu=pt"
+
+          # disable usb autosuspend
+          "usbcore.autosuspend=-1"
+
+          # allow systemd to set and save the backlight state
+          "acpi_backlight=native"
+
+          # prevent the kernel from blanking plymouth out of the fb
+          "fbcon=nodefer"
+
+          # disable boot logo
+          "logo.nologo"
+
+          # disable the cursor in vt to get a black screen during intermissions
+          "vt.global_cursor_default=0"
+        ]
+        ++ optionals cfg.silentBoot [
+          # tell the kernel to not be verbose, the voices are too loud
+          "quiet"
+
+          # kernel log message level
+          "loglevel=3" # 1: system is unusable | 3: error condition | 7: very verbose
+
+          # udev log message level
+          "udev.log_level=3"
+
+          # lower the udev log level to show only errors or worse
+          "rd.udev.log_level=3"
+
+          # disable systemd status messages
+          # rd prefix means systemd-udev will be used instead of initrd
+          "systemd.show_status=auto"
+          "rd.systemd.show_status=auto"
+        ];
+    };
+  };
+}

modules/nixos/boot/plymouth.nix

@@ -0,0 +1,31 @@
+{
+  lib,
+  pkgs,
+  inputs',
+  config,
+  ...
+}: let
+  inherit (lib.meta) getExe';
+  inherit (lib.modules) mkIf;
+  inherit (lib.options) mkEnableOption;
+
+  cfg = config.olympus.system.boot.plymouth;
+in {
+  options.olympus.system.boot.plymouth.enable = mkEnableOption "plymouth boot splash";
+
+  config = mkIf cfg.enable {
+    boot.plymouth = {
+      enable = true;
+      theme = "mikuboot";
+      themePackages = [
+        inputs'.haipkgs.packages.mikuboot
+      ];
+    };
+
+    # make plymouth work with sleep
+    powerManagement = {
+      powerDownCommands = "${getExe' pkgs.plymouth "plymouth"} --show-splash";
+      resumeCommands = "${getExe' pkgs.plymouth "plymouth"} --quit";
+    };
+  };
+}