manual-config: Fully general cross-compiling

In the most general case, the cross and native kernel may differ in
patches and configuration file as well as architecture, kernel target,
etc. It's probably overkill to support that case, but since it was
doable without much duplication and it will make integrating with the
existing cross-compilation support in the generic kernel I decided to
implement it anyway.

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

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

@@ -19,21 +19,40 @@ in {
   src,
   # Any patches
   kernelPatches ? [],
-  # The kernel .config file
+  # Patches for native compiling only
+  nativeKernelPatches ? [],
+  # Patches for cross compiling only
+  crossKernelPatches ? [],
+  # The native kernel .config file
   configfile,
+  # The cross kernel .config file
+  crossConfigfile ? configfile,
   # Manually specified nixexpr representing the config
   # If unspecified, this will be autodetected from the .config
   config ? stdenv.lib.optionalAttrs allowImportFromDerivation (readConfig configfile),
+  # Cross-compiling config
+  crossConfig ? if allowImportFromDerivation then (readConfig crossConfigfile) else config,
   # Whether to utilize the controversial import-from-derivation feature to parse the config
   allowImportFromDerivation ? false
 }:
 
-let config_ = config; in
-
 let
   inherit (stdenv.lib)
-    hasAttr getAttr optionalAttrs optional optionalString maintainers platforms;
+    hasAttr getAttr optional optionalString maintainers platforms;
 
+  installkernel = writeTextFile { name = "installkernel"; executable=true; text = ''
+    #!${stdenv.shell} -e
+    mkdir -p $4
+    cp -av $2 $4
+    cp -av $3 $4
+  ''; };
+
+  commonMakeFlags = [
+    "O=$(buildRoot)"
+  ];
+
+  drvAttrs = config_: platform: kernelPatches: configfile:
+    let
       config = let attrName = attr: "CONFIG_" + attr; in {
         isSet = attr: hasAttr (attrName attr) config;
 
@@ -50,25 +69,11 @@ let
         isDisabled = attr: (!(config.isSet attr)) || (config.isNo attr);
       } // config_;
 
-  installkernel = writeTextFile { name = "installkernel"; executable=true; text = ''
-    #!${stdenv.shell} -e
-    mkdir -p $4
-    cp -av $2 $4
-    cp -av $3 $4
-  '';};
-
       isModular = config.isYes "MODULES";
 
       installsFirmware = (config.isEnabled "FW_LOADER") &&
         (isModular || (config.isDisabled "FIRMWARE_IN_KERNEL"));
 
-  commonMakeFlags = [
-    "O=$(buildRoot)"
-  ];
-
-  # Some image types need special install targets (e.g. uImage is installed with make uinstall)
-  installTarget = target: [ (if target == "uImage" then "uinstall" else "install") ];
-
       sourceRoot = stdenv.mkDerivation {
         name = "linux-source-${version}";
 
@@ -83,7 +88,9 @@ let
               echo "stripping FHS paths in \`$mf'..."
               sed -i "$mf" -e 's|/usr/bin/||g ; s|/bin/||g ; s|/sbin/||g'
           done
+
           sed -i Makefile -e 's|= depmod|= ${kmod}/sbin/depmod|'
+
           # Patch kconfig to print "###" after every question so that
           # generate-config.pl from the generic builder can answer them.
           # This only affects oldaskconfig.
@@ -95,13 +102,7 @@ let
           mv $sourceRoot $out
         '';
       };
-in
+    in {
-
-stdenv.mkDerivation {
-  name = "linux-${version}";
-
-  enableParallelBuilding = true;
-
       outputs = if isModular then [ "out" "dev" ] else null;
 
       passthru = {
@@ -123,13 +124,6 @@ stdenv.mkDerivation {
         runHook postConfigure
       '';
 
-  nativeBuildInputs = [ perl bc nettools ] ++ optional (stdenv.platform.uboot != null)
-    (ubootChooser stdenv.platform.uboot);
-
-  makeFlags = commonMakeFlags ++ [
-    "ARCH=${stdenv.platform.kernelArch}"
-  ];
-
       buildFlags = [ stdenv.platform.kernelTarget ] ++ optional isModular "modules";
 
       installFlags = [
@@ -138,20 +132,8 @@ stdenv.mkDerivation {
       ] ++ (optional isModular "INSTALL_MOD_PATH=$(out)")
       ++ optional installsFirmware "INSTALL_FW_PATH=$(out)/lib/firmware";
 
-  installTargets = installTarget stdenv.platform.kernelTarget;
+      # Some image types need special install targets (e.g. uImage is installed with make uinstall)
-
+      installTargets = [ (if platform.kernelTarget == "uImage" then "uinstall" else "install") ];
-  crossAttrs = let cp = stdenv.cross.platform; in {
-    buildFlags = [ cp.kernelTarget ] ++ optional isModular "modules";
-
-    makeFlags = commonMakeFlags ++ [
-      "ARCH=${cp.kernelArch}"
-      "CROSS_COMPILE=$(crossConfig)-"
-    ];
-
-    installTargets = installTarget cp.kernelTarget;
-
-    buildInputs = optional (cp.uboot != null) (ubootChooser cp.uboot).crossDrv;
-  };
 
       postInstall = optionalString installsFirmware ''
         mkdir -p $out/lib/firmware
@@ -176,6 +158,34 @@ stdenv.mkDerivation {
               "s|${sourceRoot}|$NIX_STORE/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-${sourceRoot.name}|g"
         fi
       '' else null;
+    };
+in
+
+stdenv.mkDerivation ((drvAttrs config stdenv.platform (kernelPatches ++ nativeKernelPatches) configfile) // {
+  name = "linux-${version}";
+
+  enableParallelBuilding = true;
+
+  nativeBuildInputs = [ perl bc nettools ] ++ optional (stdenv.platform.uboot != null)
+    (ubootChooser stdenv.platform.uboot);
+
+  makeFlags = commonMakeFlags ++ [
+    "ARCH=${stdenv.platform.kernelArch}"
+  ];
+
+  crossAttrs = let cp = stdenv.cross.platform; in {
+    (drvAttrs crossConfig cp (kernelPatches ++ crossKernelPatches) crossConfigfile) // {
+      makeFlags = commonMakeFlags ++ [
+        "ARCH=${cp.kernelArch}"
+        "CROSS_COMPILE=$(crossConfig)-"
+      ];
+
+      # !!! uboot has messed up cross-compiling, nativeDrv builds arm tools on x86,
+      # crossDrv builds x86 tools on x86 (but arm uboot). If this is fixed, uboot
+      # can just go into buildInputs (but not nativeBuildInputs since cp.uboot
+      # may be different from stdenv.platform.uboot)
+      buildInputs = optional (cp.uboot != null) (ubootChooser cp.uboot).crossDrv;
+  };
 
   meta = {
     description = "The Linux kernel";
@@ -186,4 +196,4 @@ stdenv.mkDerivation {
     ];
     platforms = platforms.linux;
   };
-}
+})