linux/manual-config: Cross-compiling support

With this, I was able to successfully compile a defconfig kernel for the
sheevaplug, though I didn't actually try to run it (not having a
sheevaplug myself).

For native compiles, the most significant difference is that the
platform's kernel target is built directly rather than hoping the
default make target will pull it in.

Also some stylistic improvements along the way.

Signed-off-by: Shea Levy <shea@shealevy.com>

pkgs/os-specific/linux/kernel/manual-config.nix

@@ -1,4 +1,4 @@
-{ stdenv, runCommand, nettools, bc, perl, kmod, writeTextFile }:
+{ stdenv, runCommand, nettools, bc, perl, kmod, writeTextFile, ubootChooser }:
 
 let
   inherit (stdenv.lib)
@@ -58,10 +58,10 @@ in
 }:
 
 let
-  installkernel = name: writeTextFile { name = "installkernel"; executable=true; text = ''
-    #!/bin/sh
-    mkdir $4
-    cp -av $2 $4/${name}
+  installkernel = writeTextFile { name = "installkernel"; executable=true; text = ''
+    #!${stdenv.shell} -e
+    mkdir -p $4
+    cp -av $2 $4
     cp -av $3 $4
   '';};
 
@@ -72,9 +72,10 @@ let
 
   commonMakeFlags = [
     "O=$(buildRoot)"
-    "INSTALL_PATH=$(out)"
-  ] ++ (optional isModular "INSTALL_MOD_PATH=$(out)")
-  ++ optional installsFirmware "INSTALL_FW_PATH=$(out)/lib/firmware";
+  ];
+
+  # Some image types need special install targets (e.g. uImage is installed with make uinstall)
+  installTarget = target: [ (if target == "uImage" then "uinstall" else "install") ];
 
   sourceRoot = stdenv.mkDerivation {
     name = "linux-${version}-source";
@@ -126,16 +127,34 @@ stdenv.mkDerivation {
     runHook postConfigure
   '';
 
-  nativeBuildInputs = [ perl bc nettools ];
+  nativeBuildInputs = [ perl bc nettools ] ++ optional (stdenv.platform.uboot != null)
+    (ubootChooser stdenv.platform.uboot);
 
   makeFlags = commonMakeFlags ++ [
-   "INSTALLKERNEL=${installkernel stdenv.platform.kernelTarget}"
+    "ARCH=${stdenv.platform.kernelArch}"
   ];
 
-  crossAttrs = {
+  buildFlags = [ stdenv.platform.kernelTarget ] ++ optional isModular "modules";
+
+  installFlags = [
+    "INSTALLKERNEL=${installkernel}"
+    "INSTALL_PATH=$(out)"
+  ] ++ (optional isModular "INSTALL_MOD_PATH=$(out)")
+  ++ optional installsFirmware "INSTALL_FW_PATH=$(out)/lib/firmware";
+
+  installTargets = installTarget stdenv.platform.kernelTarget;
+
+  crossAttrs = let cp = stdenv.cross.platform; in {
+    buildFlags = [ cp.kernelTarget ] ++ optional isModular "modules";
+
     makeFlags = commonMakeFlags ++ [
-     "INSTALLKERNEL=${installkernel stdenv.cross.platform.kernelTarget}"
+      "ARCH=${cp.kernelArch}"
+      "CROSS_COMPILE=$(crossConfig)-"
     ];
+
+    installTargets = installTarget cp.kernelTarget;
+
+    buildInputs = optional (cp.uboot != null) (ubootChooser cp.uboot).crossDrv;
   };
 
   postInstall = optionalString installsFirmware ''
@@ -143,7 +162,7 @@ stdenv.mkDerivation {
   '' + (if isModular then ''
     make modules_install $makeFlags "''${makeFlagsArray[@]}" \
       $installFlags "''${installFlagsArray[@]}"
-    rm -f $out/lib/modules/${modDirVersion}/build
+    unlink $out/lib/modules/${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
@@ -154,7 +173,7 @@ stdenv.mkDerivation {
 
   postFixup = if isModular then ''
     if [ -z "$dontStrip" ]; then
-        find $out -name "*.ko" -print0 | xargs -0 -r strip -S
+        find $out -name "*.ko" -print0 | xargs -0 -r ''${crossConfig+$crossConfig-}strip -S
         # Remove all references to the source directory to avoid unneeded
         # runtime dependencies
         find $out -name "*.ko" -print0 | xargs -0 -r sed -i \

pkgs/top-level/all-packages.nix

@@ -6952,7 +6952,7 @@ let
 
   # A function to build a manually-configured kernel
   linuxManualConfig = import ../os-specific/linux/kernel/manual-config.nix {
-    inherit (pkgs) stdenv runCommand nettools bc perl kmod writeTextFile;
+    inherit (pkgs) stdenv runCommand nettools bc perl kmod writeTextFile ubootChooser;
   };
 
   keyutils = callPackage ../os-specific/linux/keyutils { };