kernel: Enable cross compiling

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

@@ -51,7 +51,7 @@ with stdenv.lib;
 
   # Bump the maximum number of CPUs to support systems like EC2 x1.*
   # instances and Xeon Phi.
-  ${optionalString (stdenv.system == "x86_64-linux" || stdenv.system == "aarch64-linux") ''
+  ${optionalString (stdenv.hostPlatform.system == "x86_64-linux" || stdenv.hostPlatform.system == "aarch64-linux") ''
     NR_CPUS 384
   ''}
 
@@ -347,11 +347,12 @@ with stdenv.lib;
   SECURITY_SELINUX_BOOTPARAM_VALUE 0 # Disable SELinux by default
   SECURITY_YAMA? y # Prevent processes from ptracing non-children processes
   DEVKMEM n # Disable /dev/kmem
-  ${if versionOlder version "3.14" then ''
+  ${optionalString (! stdenv.hostPlatform.isArm)
-    CC_STACKPROTECTOR? y # Detect buffer overflows on the stack
+    (if versionOlder version "3.14" then ''
-  '' else ''
+        CC_STACKPROTECTOR? y # Detect buffer overflows on the stack
-    CC_STACKPROTECTOR_REGULAR? y
+      '' else ''
-  ''}
+        CC_STACKPROTECTOR_REGULAR? y
+      '')}
   ${optionalString (versionAtLeast version "3.12") ''
     USER_NS y # Support for user namespaces
   ''}

pkgs/os-specific/linux/kernel/generic.nix

@@ -1,4 +1,4 @@
-{ stdenv, perl, buildLinux
+{ stdenv, buildPackages, perl, buildLinux
 
 , # The kernel source tarball.
   src
@@ -23,7 +23,7 @@
   # symbolic name and `patch' is the actual patch.  The patch may
   # optionally be compressed with gzip or bzip2.
   kernelPatches ? []
-, ignoreConfigErrors ? stdenv.platform.name != "pc"
+, ignoreConfigErrors ? hostPlatform.platform.name != "pc"
 , extraMeta ? {}
 , hostPlatform
 , ...
@@ -58,37 +58,29 @@ let
     in lib.concatStringsSep "\n" ([baseConfig] ++ configFromPatches);
 
   configfile = stdenv.mkDerivation {
-    inherit ignoreConfigErrors;
+    #inherit ignoreConfigErrors;
     name = "linux-config-${version}";
 
     generateConfig = ./generate-config.pl;
 
     kernelConfig = kernelConfigFun config;
 
-    nativeBuildInputs = [ perl ];
+    nativeBuildInputs = [ buildPackages.stdenv.cc perl ];
 
-    platformName = stdenv.platform.name;
+    platformName = hostPlatform.platform.name;
-    kernelBaseConfig = stdenv.platform.kernelBaseConfig;
+    kernelBaseConfig = hostPlatform.platform.kernelBaseConfig;
-    kernelTarget = stdenv.platform.kernelTarget;
+    kernelTarget = hostPlatform.platform.kernelTarget;
-    autoModules = stdenv.platform.kernelAutoModules;
+    autoModules = hostPlatform.platform.kernelAutoModules;
-    preferBuiltin = stdenv.platform.kernelPreferBuiltin or false;
+    preferBuiltin = hostPlatform.platform.kernelPreferBuiltin or false;
-    arch = stdenv.platform.kernelArch;
+    arch = hostPlatform.platform.kernelArch;
+
+    # TODO(@Ericson2314): No null next hash break
+    ignoreConfigErrors = if stdenv.hostPlatform == stdenv.buildPlatform then null else true;
 
     crossAttrs = let
         cp = hostPlatform.platform;
       in {
-        arch = cp.kernelArch;
-        platformName = cp.name;
-        kernelBaseConfig = cp.kernelBaseConfig;
-        kernelTarget = cp.kernelTarget;
-        autoModules = cp.kernelAutoModules;
-
-        # Just ignore all options that don't apply (We are lazy).
         ignoreConfigErrors = true;
-
-        kernelConfig = kernelConfigFun configCross;
-
-        inherit (kernel.crossDrv) src patches preUnpack;
       };
 
     prePatch = kernel.prePatch + ''
@@ -103,7 +95,7 @@ let
       cd $buildRoot
 
       # Get a basic config file for later refinement with $generateConfig.
-      make -C ../$sourceRoot O=$PWD $kernelBaseConfig ARCH=$arch
+      make HOSTCC=${buildPackages.stdenv.cc.targetPrefix}gcc -C ../$sourceRoot O=$PWD $kernelBaseConfig ARCH=$arch
 
       # Create the config file.
       echo "generating kernel configuration..."
@@ -122,11 +114,7 @@ let
 
     configfile = configfile.nativeDrv or configfile;
 
-    crossConfigfile = configfile.crossDrv or configfile;
-
     config = { CONFIG_MODULES = "y"; CONFIG_FW_LOADER = "m"; };
-
-    crossConfig = { CONFIG_MODULES = "y"; CONFIG_FW_LOADER = "m"; };
   };
 
   passthru = {
@@ -134,12 +122,4 @@ let
     passthru = kernel.passthru // (removeAttrs passthru [ "passthru" ]);
   };
 
-  addPassthru' = lib.extendDerivation true passthru;
+in lib.extendDerivation true passthru kernel
-
-  nativeDrv = addPassthru' kernel.nativeDrv;
-
-  crossDrv = addPassthru' kernel.crossDrv;
-
-in if kernel ? crossDrv
-   then nativeDrv // { inherit nativeDrv crossDrv; }
-   else addPassthru' kernel

pkgs/os-specific/linux/kernel/linux-4.13.nix

@@ -1,4 +1,4 @@
-{ stdenv, hostPlatform, fetchurl, perl, buildLinux, ... } @ args:
+{ stdenv, buildPackages, hostPlatform, fetchurl, perl, buildLinux, ... } @ args:
 
 import ./generic.nix (args // rec {
   version = "4.13.16";

pkgs/os-specific/linux/kernel/linux-4.14.nix

@@ -1,4 +1,4 @@
-{ stdenv, hostPlatform, fetchurl, perl, buildLinux, ... } @ args:
+{ stdenv, buildPackages, hostPlatform, fetchurl, perl, buildLinux, ... } @ args:
 
 with stdenv.lib;
 

pkgs/os-specific/linux/kernel/linux-4.4.nix

@@ -1,4 +1,4 @@
-{ stdenv, hostPlatform, fetchurl, perl, buildLinux, ... } @ args:
+{ stdenv, buildPackages, hostPlatform, fetchurl, perl, buildLinux, ... } @ args:
 
 import ./generic.nix (args // rec {
   version = "4.4.111";

pkgs/os-specific/linux/kernel/linux-4.9.nix

@@ -1,4 +1,4 @@
-{ stdenv, hostPlatform, fetchurl, perl, buildLinux, ... } @ args:
+{ stdenv, buildPackages, hostPlatform, fetchurl, perl, buildLinux, ... } @ args:
 
 import ./generic.nix (args // rec {
   version = "4.9.76";

pkgs/os-specific/linux/kernel/linux-beagleboard.nix

@@ -1,4 +1,4 @@
-{ stdenv, hostPlatform, fetchFromGitHub, perl, buildLinux, ... } @ args:
+{ stdenv, buildPackages, hostPlatform, fetchFromGitHub, perl, buildLinux, ... } @ args:
 
 let
   modDirVersion = "4.9.61";

pkgs/os-specific/linux/kernel/linux-hardened-copperhead.nix

@@ -1,4 +1,4 @@
-{ stdenv, hostPlatform, fetchFromGitHub, perl, buildLinux, ... } @ args:
+{ stdenv, buildPackages, hostPlatform, fetchFromGitHub, perl, buildLinux, ... } @ args:
 
 with stdenv.lib;
 

pkgs/os-specific/linux/kernel/linux-mptcp.nix

@@ -1,4 +1,4 @@
-{ stdenv, hostPlatform, fetchFromGitHub, perl, buildLinux, ... } @ args:
+{ stdenv, buildPackages, hostPlatform, fetchFromGitHub, perl, buildLinux, ... } @ args:
 
 import ./generic.nix (rec {
   mptcpVersion = "0.93";

pkgs/os-specific/linux/kernel/linux-rpi.nix

@@ -1,4 +1,4 @@
-{ stdenv, hostPlatform, fetchFromGitHub, perl, buildLinux, ... } @ args:
+{ stdenv, buildPackages, hostPlatform, fetchFromGitHub, perl, buildLinux, ... } @ args:
 
 let
   modDirVersion = "4.9.59";

pkgs/os-specific/linux/kernel/linux-samus-4.12.nix

@@ -1,4 +1,4 @@
-{ stdenv, hostPlatform, fetchFromGitHub, perl, buildLinux, ncurses, ... } @ args:
+{ stdenv, buildPackages, hostPlatform, fetchFromGitHub, perl, buildLinux, ncurses, ... } @ args:
 
 import ./generic.nix (args // rec {
   version = "4.12.2";

pkgs/os-specific/linux/kernel/linux-testing-bcachefs.nix

@@ -1,4 +1,4 @@
-{ stdenv, hostPlatform, fetchgit, perl, buildLinux, ... } @ args:
+{ stdenv, buildPackages, hostPlatform, fetchgit, perl, buildLinux, ... } @ args:
 
 import ./generic.nix (args // rec {
   version = "4.11.2017.08.23";

pkgs/os-specific/linux/kernel/linux-testing.nix

@@ -1,4 +1,4 @@
-{ stdenv, hostPlatform, fetchurl, perl, buildLinux, libelf, utillinux, ... } @ args:
+{ stdenv, buildPackages, hostPlatform, fetchurl, perl, buildLinux, libelf, utillinux, ... } @ args:
 
 import ./generic.nix (args // rec {
   version = "4.15-rc8";

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

@@ -1,6 +1,6 @@
-{ runCommand, nettools, bc, perl, gmp, libmpc, mpfr, kmod, openssl
+{ buildPackages, runCommand, nettools, bc, perl, gmp, libmpc, mpfr, kmod, openssl
-, libelf ? null
+, libelf
-, utillinux ? null
+, utillinux
 , writeTextFile, ubootTools
 , hostPlatform
 }:
@@ -26,19 +26,11 @@ in {
   src,
   # Any patches
   kernelPatches ? [],
-  # Patches for native compiling only
+  # The kernel .config file
-  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,
   # Use defaultMeta // extraMeta
   extraMeta ? {},
   # Whether to utilize the controversial import-from-derivation feature to parse the config
@@ -61,8 +53,8 @@ let
 
   commonMakeFlags = [
     "O=$(buildRoot)"
-  ] ++ stdenv.lib.optionals (stdenv.platform ? kernelMakeFlags)
+  ] ++ stdenv.lib.optionals (hostPlatform.platform ? kernelMakeFlags)
-    stdenv.platform.kernelMakeFlags;
+    hostPlatform.platform.kernelMakeFlags;
 
   drvAttrs = config_: platform: kernelPatches: configfile:
     let
@@ -233,13 +225,13 @@ let
           maintainers.thoughtpolice
         ];
         platforms = platforms.linux;
-      } // extraMeta;
+      };
-    };
+    } // extraMeta;
 in
 
 assert stdenv.lib.versionAtLeast version "4.14" -> libelf != null;
 assert stdenv.lib.versionAtLeast version "4.15" -> utillinux != null;
-stdenv.mkDerivation ((drvAttrs config stdenv.platform (kernelPatches ++ nativeKernelPatches) configfile) // {
+stdenv.mkDerivation ((drvAttrs config hostPlatform.platform kernelPatches configfile) // {
   name = "linux-${version}";
 
   enableParallelBuilding = true;
@@ -253,20 +245,11 @@ stdenv.mkDerivation ((drvAttrs config stdenv.platform (kernelPatches ++ nativeKe
   hardeningDisable = [ "bindnow" "format" "fortify" "stackprotector" "pic" ];
 
   makeFlags = commonMakeFlags ++ [
-    "ARCH=${stdenv.platform.kernelArch}"
+    "HOSTCC=${buildPackages.stdenv.cc.targetPrefix}gcc"
+    "ARCH=${stdenv.hostPlatform.platform.kernelArch}"
+  ] ++ stdenv.lib.optional (stdenv.hostPlatform != stdenv.buildPlatform) [
+    "CROSS_COMPILE=${stdenv.cc.targetPrefix}"
   ];
 
-  karch = stdenv.platform.kernelArch;
+  karch = hostPlatform.platform.kernelArch;
-
-  crossAttrs = let cp = hostPlatform.platform; in
-    (drvAttrs crossConfig cp (kernelPatches ++ crossKernelPatches) crossConfigfile) // {
-      makeFlags = commonMakeFlags ++ [
-        "ARCH=${cp.kernelArch}"
-        "CROSS_COMPILE=$(crossConfig)-"
-      ];
-
-      karch = cp.kernelArch;
-
-      nativeBuildInputs = optional (cp.kernelTarget == "uImage") ubootTools;
-  };
 })

pkgs/os-specific/linux/kernel/perf.nix

@@ -23,8 +23,8 @@ stdenv.mkDerivation {
   # perf refers both to newt and slang
   # binutils is required for libbfd.
   nativeBuildInputs = [ asciidoc xmlto docbook_xsl docbook_xml_dtd_45 libxslt
-      flex bison libiberty libaudit makeWrapper pkgconfig ];
+      flex bison libiberty libaudit makeWrapper pkgconfig python perl ];
-  buildInputs = [ elfutils python perl newt slang libunwind binutils zlib ] ++
+  buildInputs = [ elfutils newt slang libunwind binutils zlib ] ++
     stdenv.lib.optional withGtk gtk2;
 
   # Note: we don't add elfutils to buildInputs, since it provides a
@@ -40,6 +40,10 @@ stdenv.mkDerivation {
       "-Wno-error=unused-const-variable" "-Wno-error=misleading-indentation"
     ];
 
+  makeFlags = if stdenv.hostPlatform == stdenv.buildPlatform
+    then null
+    else "CROSS_COMPILE=${stdenv.cc.prefix}";
+
   installFlags = "install install-man ASCIIDOC8=1";
 
   preFixup = ''
@@ -47,15 +51,6 @@ stdenv.mkDerivation {
       --prefix PATH : "${binutils}/bin"
   '';
 
-  crossAttrs = {
-    /* I don't want cross-python or cross-perl -
-       I don't know if cross-python even works */
-    propagatedBuildInputs = [ elfutils.crossDrv newt.crossDrv ];
-    makeFlags = "CROSS_COMPILE=${stdenv.cc.targetPrefix}";
-    elfutils = elfutils.crossDrv;
-    inherit (kernel.crossDrv) src patches;
-  };
-
   meta = {
     homepage = https://perf.wiki.kernel.org/;
     description = "Linux tools to profile with performance counters";