From 4f29bdd3ed9be1b16627522d8b247b9baf185566 Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Wed, 20 Sep 2023 17:57:17 +0100
Subject: [PATCH] detect arch in kernel and uimage

also move kernel builder to pkgs/

FIXME we need to straighten out the mess in calling
dtb.nix/uimage.nix
---
 modules/kernel.nix                 |  2 +-
 modules/outputs.nix                |  4 ++--
 pkgs/default.nix                   |  2 ++
 pkgs/kernel/default.nix            |  8 +++++++-
 {kernel => pkgs/kernel}/dtb.nix    |  0
 {kernel => pkgs/kernel}/uimage.nix | 21 ++++++++++++++++-----
 6 files changed, 28 insertions(+), 9 deletions(-)
 rename {kernel => pkgs/kernel}/dtb.nix (100%)
 rename {kernel => pkgs/kernel}/uimage.nix (55%)

diff --git a/modules/kernel.nix b/modules/kernel.nix
index d73665e..ff2d9de 100644
--- a/modules/kernel.nix
+++ b/modules/kernel.nix
@@ -24,7 +24,7 @@ in {
       extraPatchPhase = mkOption {
         default = "true";
         type = types.lines;
-      } ;
+      };
       config = mkOption {
         description = ''
           Kernel config options, as listed in Kconfig* files in the
diff --git a/modules/outputs.nix b/modules/outputs.nix
index b0edf17..02c3cd1 100644
--- a/modules/outputs.nix
+++ b/modules/outputs.nix
@@ -62,14 +62,14 @@ in
       kernel = liminix.builders.kernel.override {
         inherit (config.kernel) config src extraPatchPhase;
       };
-      dtb =  (callPackage ../kernel/dtb.nix {}) {
+      dtb = liminix.builders.dtb {
         inherit (config.boot) commandLine;
         dts = config.hardware.dts.src;
         includes = config.hardware.dts.includes ++ [
           "${kernel.headers}/include"
         ];
       };
-      uimage = (callPackage ../kernel/uimage.nix {}) {
+      uimage = liminix.builders.uimage {
         commandLine = concatStringsSep " " config.boot.commandLine;
         inherit (config.hardware) loadAddress entryPoint;
         inherit kernel;
diff --git a/pkgs/default.nix b/pkgs/default.nix
index e1fa46c..a7233c3 100644
--- a/pkgs/default.nix
+++ b/pkgs/default.nix
@@ -16,6 +16,8 @@ in {
     networking =  callPackage ./liminix-tools/networking {};
     builders =  {
       squashfs = callPackage ./liminix-tools/builders/squashfs.nix {};
+      dtb = callPackage ./kernel/dtb.nix {};
+      uimage = callPackage ./kernel/uimage.nix {};
       kernel = callPackage ./kernel {};
     };
     callService = path : parameters :
diff --git a/pkgs/kernel/default.nix b/pkgs/kernel/default.nix
index b2b8b9f..d6b8df4 100644
--- a/pkgs/kernel/default.nix
+++ b/pkgs/kernel/default.nix
@@ -11,6 +11,12 @@
 let
   writeConfig = import ./write-kconfig.nix { inherit lib writeText; };
   kconfigFile = writeConfig "kconfig" config;
+  arch = if stdenv.isMips
+         then "mips"
+         else if stdenv.isAarch64
+         then "arm64"
+         else throw "unknown arch";
+
   inherit lib; in
 stdenv.mkDerivation rec {
   name = "kernel";
@@ -28,7 +34,7 @@ stdenv.mkDerivation rec {
     "-I${openssl.dev}/include -L${openssl.out}/lib -L${ncurses.out}/lib";
   PKG_CONFIG_PATH = "./pkgconfig";
   CROSS_COMPILE = stdenv.cc.bintools.targetPrefix;
-  ARCH = "mips";  # kernel uses "mips" here for both mips and mipsel
+  ARCH = arch;
   KBUILD_BUILD_HOST = "liminix.builder";
 
   dontStrip = true;
diff --git a/kernel/dtb.nix b/pkgs/kernel/dtb.nix
similarity index 100%
rename from kernel/dtb.nix
rename to pkgs/kernel/dtb.nix
diff --git a/kernel/uimage.nix b/pkgs/kernel/uimage.nix
similarity index 55%
rename from kernel/uimage.nix
rename to pkgs/kernel/uimage.nix
index c92faa8..d0882f8 100644
--- a/kernel/uimage.nix
+++ b/pkgs/kernel/uimage.nix
@@ -3,6 +3,7 @@
 , stdenv
 , ubootTools
 , dtc
+, lib
 } :
 let
   objcopy = "${stdenv.cc.bintools.targetPrefix}objcopy";
@@ -37,11 +38,21 @@ stdenv.mkDerivation {
 	  ${objcopy} --update-section .appended_dtb=tmp.dtb vmlinux.elf || ${objcopy} --add-section .appended_dtb=${dtb} vmlinux.elf
   '';
 
-  buildPhase = ''
-    ${objcopy} -O binary -R .reginfo -R .notes -R .note -R .comment -R .mdebug -R .note.gnu.build-id -S vmlinux.elf vmlinux.bin
-    rm -f vmlinux.bin.lzma ; lzma -k -z  vmlinux.bin
-    mkimage -A mips -O linux -T kernel -C lzma -a ${loadAddress} -e ${entryPoint} -n 'MIPS Liminix Linux ${extraName}' -d vmlinux.bin.lzma kernel.uimage
-  '';
+  buildPhase =
+    let arch =
+          # per output of "mkimage -A list". I *think* these
+          # are the same as the kernel arch convention, but
+          # maybe that's coincidence
+          if stdenv.isMips
+          then "mips"
+          else if stdenv.isAarch64
+          then "arm64"
+          else throw "unknown arch";
+    in ''
+      ${objcopy} -O binary -R .reginfo -R .notes -R .note -R .comment -R .mdebug -R .note.gnu.build-id -S vmlinux.elf vmlinux.bin
+      rm -f vmlinux.bin.lzma ; lzma -k -z  vmlinux.bin
+      mkimage -A ${arch} -O linux -T kernel -C lzma -a ${loadAddress} -e ${entryPoint} -n '${lib.toUpper arch} Liminix Linux ${extraName}' -d vmlinux.bin.lzma kernel.uimage
+    '';
   installPhase = ''
     cp kernel.uimage $out
   '';