Simplify flake and expose host pkgs

The configuration of the machines is now moved to m/

m/xeon08/kernel/kernel.nix

@@ -0,0 +1,68 @@
+{ pkgs, lib, ... }:
+
+let
+  #fcs-devel = pkgs.linuxPackages_custom {
+  #   version = "6.2.8";
+  #   src = /mnt/data/kernel/fcs/kernel/src;
+  #   configfile = /mnt/data/kernel/fcs/kernel/configs/defconfig;
+  #};
+
+  #fcsv1 = fcs-kernel "bc11660676d3d68ce2459b9fb5d5e654e3f413be" false;
+  #fcsv2 = fcs-kernel "db0f2eca0cd57a58bf456d7d2c7d5d8fdb25dfb1" false;
+  #fcsv1-lockdep = fcs-kernel "bc11660676d3d68ce2459b9fb5d5e654e3f413be" true;
+  #fcsv2-lockdep = fcs-kernel "db0f2eca0cd57a58bf456d7d2c7d5d8fdb25dfb1" true;
+  #fcs-kernel = gitCommit: lockdep: pkgs.linuxPackages_custom {
+  #   version = "6.2.8";
+  #   src = builtins.fetchGit {
+  #     url = "git@bscpm03.bsc.es:ompss-kernel/linux.git";
+  #     rev = gitCommit;
+  #     ref = "fcs";
+  #   };
+  #   configfile = if lockdep then ./configs/lockdep else ./configs/defconfig;
+  #};
+
+  kernel = nixos-fcsv2;
+
+  nixos-fcs-kernel = {gitCommit, lockStat ? false, preempt ? false}: pkgs.linuxPackagesFor (pkgs.buildLinux rec {
+    version = "6.2.8";
+    src = builtins.fetchGit {
+      url = "git@bscpm03.bsc.es:ompss-kernel/linux.git";
+      rev = gitCommit;
+      ref = "fcs";
+    };
+    structuredExtraConfig = with lib.kernel; {
+      # add general custom kernel options here
+    } // lib.optionalAttrs lockStat {
+      LOCK_STAT = yes;
+    } // lib.optionalAttrs preempt {
+      PREEMPT = lib.mkForce yes;
+      PREEMPT_VOLUNTARY = lib.mkForce no;
+    };
+    kernelPatches = [];
+    extraMeta.branch = lib.versions.majorMinor version;
+  });
+
+  nixos-fcsv1 = nixos-fcs-kernel {gitCommit = "bc11660676d3d68ce2459b9fb5d5e654e3f413be";};
+  nixos-fcsv2 = nixos-fcs-kernel {gitCommit = "db0f2eca0cd57a58bf456d7d2c7d5d8fdb25dfb1";};
+  nixos-fcsv1-lockstat = nixos-fcs-kernel {
+    gitCommit = "bc11660676d3d68ce2459b9fb5d5e654e3f413be";
+    lockStat = true;
+  };
+  nixos-fcsv2-lockstat = nixos-fcs-kernel {
+    gitCommit = "db0f2eca0cd57a58bf456d7d2c7d5d8fdb25dfb1";
+    lockStat = true;
+  };
+  nixos-fcsv2-lockstat-preempt = nixos-fcs-kernel {
+    gitCommit = "db0f2eca0cd57a58bf456d7d2c7d5d8fdb25dfb1";
+    lockStat = true;
+    preempt = true;
+  };
+  latest = pkgs.linuxPackages_latest;
+
+in {
+  imports = [
+    ./lttng.nix
+    ./perf.nix
+  ];
+  boot.kernelPackages = lib.mkForce kernel;
+}

m/xeon08/kernel/lttng.nix

@@ -0,0 +1,43 @@
+{ config, pkgs, lib, ... }:
+
+let
+
+  # The lttng btrfs probe crashes at compile time because of an undefined
+  # function. This disables the btrfs tracepoints to avoid the issue.
+
+  # Also enable lockdep tracepoints, this is disabled by default because it
+  # does not work well on architectures other than x86_64 (i think that arm) as
+  # I was told on the mailing list.
+  lttng-modules-fixed = config.boot.kernelPackages.lttng-modules.overrideAttrs (finalAttrs: previousAttrs: {
+    patchPhase = (lib.optionalString (previousAttrs ? patchPhase) previousAttrs.patchPhase) + ''
+      # disable btrfs
+      substituteInPlace src/probes/Kbuild \
+        --replace "  obj-\$(CONFIG_LTTNG) += lttng-probe-btrfs.o" "  #obj-\$(CONFIG_LTTNG) += lttng-probe-btrfs.o"
+
+      # enable lockdep tracepoints
+      substituteInPlace src/probes/Kbuild \
+        --replace "#ifneq (\$(CONFIG_LOCKDEP),)"                  "ifneq (\$(CONFIG_LOCKDEP),)" \
+        --replace "#  obj-\$(CONFIG_LTTNG) += lttng-probe-lock.o" "  obj-\$(CONFIG_LTTNG) += lttng-probe-lock.o" \
+        --replace "#endif # CONFIG_LOCKDEP"                       "endif # CONFIG_LOCKDEP"
+    '';
+  });
+in {
+
+  # add the lttng tools and modules to the system environment
+  boot.extraModulePackages = [ lttng-modules-fixed ];
+  environment.systemPackages = with pkgs; [
+    lttng-tools lttng-ust babeltrace
+  ];
+
+  # start the lttng root daemon to manage kernel events
+  systemd.services.lttng-sessiond = {
+    wantedBy = [ "multi-user.target" ];
+    description = "LTTng session daemon for the root user";
+    serviceConfig = {
+      User = "root";
+      ExecStart = ''
+        ${pkgs.lttng-tools}/bin/lttng-sessiond
+      '';
+    };
+  };
+}

m/xeon08/kernel/perf.nix

@@ -0,0 +1,22 @@
+{ config, pkgs, lib, ... }:
+
+{
+  # add the perf tool
+  environment.systemPackages = with pkgs; [
+    config.boot.kernelPackages.perf
+  ];
+
+  # allow non-root users to read tracing data from the kernel
+  boot.kernel.sysctl."kernel.perf_event_paranoid" = -2;
+  boot.kernel.sysctl."kernel.kptr_restrict" = 0;
+
+  # specify additionl options to the tracefs directory to allow members of the
+  # tracing group to access tracefs.
+  fileSystems."/sys/kernel/tracing" = {
+    options = [
+      "mode=755"
+      "gid=tracing"
+    ];
+  };
+}
+