linux/manual-config: put build and source trees into a separate 'dev' output.

This makes it possible to still build out-of-tree modules without making a system using this kernel depend on the full source and build tree at runtime.

Note that references to the source tree are removed from kernel modules after build.
Ideally, this would be accomplished by modifying the Makefile that puts the reference there in the first place, but I haven't tracked that down yet.

1 files changed, 22 insertions, 12 deletions

diff --git a/pkgs/os-specific/linux/kernel/manual-config.nix b/pkgs/os-specific/linux/kernel/manual-config.nix
index 28abd434b05..2191cc046e4 100644
--- a/pkgs/os-specific/linux/kernel/manual-config.nix
+++ b/pkgs/os-specific/linux/kernel/manual-config.nix
@@ -75,16 +75,6 @@ let
     "INSTALL_PATH=$(out)"
   ] ++ (optional isModular "INSTALL_MOD_PATH=$(out)")
   ++ optional installsFirmware "INSTALL_FW_PATH=$(out)/lib/firmware";
-in
-
-stdenv.mkDerivation {
-  name = "linux-${version}";
-
-  enableParallelBuilding = true;
-
-  passthru = {
-    inherit version modDirVersion config kernelPatches src;
-  };
 
   sourceRoot = stdenv.mkDerivation {
     name = "linux-${version}-source";
@@ -108,11 +98,25 @@ stdenv.mkDerivation {
       mv $sourceRoot $out
     '';
   };
+in
+
+stdenv.mkDerivation {
+  name = "linux-${version}";
+
+  enableParallelBuilding = true;
+
+  outputs = if isModular then [ "out" "dev" ] else null;
+
+  passthru = {
+    inherit version modDirVersion config kernelPatches src;
+  };
+
+  inherit sourceRoot;
 
   unpackPhase = ''
     mkdir build
     export buildRoot="$(pwd)/build"
-    cd $sourceRoot
+    cd ${sourceRoot}
   '';
 
   configurePhase = ''
@@ -140,7 +144,9 @@ stdenv.mkDerivation {
     make modules_install $makeFlags "''${makeFlagsArray[@]}" \
       $installFlags "''${installFlagsArray[@]}"
     rm -f $out/lib/modules/${modDirVersion}/build
-    mv $buildRoot $out/lib/modules/${modDirVersion}/build
+    mkdir -p $dev/lib/modules/${modDirVersion}
+    mv $out/lib/modules/${modDirVersion}/source $dev/lib/modules/${modDirVersion}/source
+    mv $buildRoot $dev/lib/modules/${modDirVersion}/build
   '' else optionalString installsFirmware ''
     make firmware_install $makeFlags "''${makeFlagsArray[@]}" \
       $installFlags "''${installFlagsArray[@]}"
@@ -149,6 +155,10 @@ stdenv.mkDerivation {
   postFixup = if isModular then ''
     if [ -z "$dontStrip" ]; then
         find $out -name "*.ko" -print0 | xargs -0 -r strip -S
+        # Remove all references to the source directory to avoid unneeded
+        # runtime dependencies
+        find $out -name "*.ko" -print0 | xargs -0 -r sed -i \
+          "s|${sourceRoot}|$NIX_STORE/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-${sourceRoot.name}|g"
     fi
   '' else null;