milkv/pioneer: fix u-root cross-compilation

Signed-off-by: Jörg Thalheim <joerg@thalheim.io>

milkv/pioneer/linuxboot-initrd.nix

@@ -1,14 +1,15 @@
-{ buildGoModule
+{ buildPackages
 , fetchFromGitHub
 , fetchpatch
 , linux-firmware
+, buildGoModule
 , ...
 }:
 
 # Based on
 # https://github.com/sophgo/bootloader-riscv/blob/e0839852d571df106db622611f4786ae17e8df0f/scripts/envsetup.sh#L809-L819
-
+let
-buildGoModule rec {
+  u-root = buildPackages.buildGoModule rec {
     pname = "u-root";
     version = "0.14.0";
     src = fetchFromGitHub {
@@ -19,36 +20,54 @@ buildGoModule rec {
     };
     vendorHash = null;
     patches = [
-    (
+      (fetchpatch {
-      fetchpatch {
         url = "https://github.com/sophgo/bootloader-riscv/commit/322c3305763872a9b88a1c85d79bca63b8fbe7a6.patch";
         hash = "sha256-l5r3DbcMqRYD5FhRBqtEIEscZAdDvjmQJE4BIAtWYWE=";
         stripLen = 1;
-      }
+      })
-    )
     ];
 
+    postInstall = ''
+      cp -r . $out/src
+    '';
+
     # We only build the u-root binary in the build phase and the initrd in the
     # postBuild hook.
     subPackages = [ "." ];
-  postBuild = ''
+
-    GOROOT="$(go env GOROOT)" $GOPATH/bin/u-root \
+    # Tests time out after 10min for native riscv64 builds on the pioneer.
+    doCheck = false;
+  };
+in
+buildGoModule {
+  name = "linuxboot-initrd";
+  src = null;
+  vendorHash = null;
+  dontUnpack = true;
+  nativeBuildInputs = [ u-root ];
+
+  buildPhase = ''
+    runHook preBuild
+    pushd ${u-root}/src
+    mkdir -p $out
+    GOROOT="$(go env GOROOT)" u-root \
       -build bb \
       -uinitcmd=boot \
       -files "${linux-firmware}/lib/firmware/amdgpu/:lib/firmware/amdgpu/" \
       -files "${linux-firmware}/lib/firmware/radeon/:lib/firmware/radeon/" \
-      -o initramfs.cpio \
+      -o $out/initramfs.cpio \
       core boot
+    popd
 
     # The vendor does not compress the initrd. We do since we include more
     # firmware files. CRC32 is required by the kernel's decompressor.
-    xz --check=crc32 initramfs.cpio
+    xz --check=crc32 $out/initramfs.cpio
+    runHook postBuild
   '';
 
   installPhase = ''
-    install -D initramfs.cpio.xz $out/initrd.img
+    runHook preInstall
+    mv $out/initramfs.cpio.xz $out/initrd.img
+    runHook postInstall
   '';
-
-  # Tests time out after 10min for native riscv64 builds on the pioneer.
-  doCheck = false;
 }