34150f86c0
BTF is a new, lightweight debug information format tailored specifically for the needs of eBPF, allowing eBPF programs to be portable across various kernel versions, configurations and distributions. This is used by bpftrace and lots of new eBPF-based tooling to avoid a dependency on LLVM on the host. BTF debug information is enabled on all major distributions: Fedora 31+, RHEL 8.2+, Ubuntu 20.10, Debian 11 and ArchLinux all have enabled it. Enabling BTF debug information requires adding two new dependencies to the kernel build: Python3 and pahole. Those will be used to generate the BTF debugging information.
337 lines
13 KiB
Nix
337 lines
13 KiB
Nix
{ lib, buildPackages, runCommand, nettools, bc, bison, flex, perl, rsync, gmp, libmpc, mpfr, openssl
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, libelf, cpio, elfutils, zstd, gawk, python3Minimal, zlib, pahole
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, writeTextFile
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}:
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let
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readConfig = configfile: import (runCommand "config.nix" {} ''
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echo "{" > "$out"
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while IFS='=' read key val; do
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[ "x''${key#CONFIG_}" != "x$key" ] || continue
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no_firstquote="''${val#\"}";
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echo ' "'"$key"'" = "'"''${no_firstquote%\"}"'";' >> "$out"
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done < "${configfile}"
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echo "}" >> $out
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'').outPath;
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in {
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lib,
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# Allow overriding stdenv on each buildLinux call
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stdenv,
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# The kernel version
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version,
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# Additional kernel make flags
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extraMakeFlags ? [],
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# The version of the kernel module directory
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modDirVersion ? version,
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# The kernel source (tarball, git checkout, etc.)
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src,
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# a list of { name=..., patch=..., extraConfig=...} patches
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kernelPatches ? [],
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# The kernel .config file
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configfile,
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# Manually specified nixexpr representing the config
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# If unspecified, this will be autodetected from the .config
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config ? lib.optionalAttrs allowImportFromDerivation (readConfig configfile),
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# Custom seed used for CONFIG_GCC_PLUGIN_RANDSTRUCT if enabled. This is
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# automatically extended with extra per-version and per-config values.
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randstructSeed ? "",
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# Use defaultMeta // extraMeta
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extraMeta ? {},
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# for module compatibility
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isZen ? false,
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isLibre ? false,
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isHardened ? false,
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# Whether to utilize the controversial import-from-derivation feature to parse the config
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allowImportFromDerivation ? false,
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# ignored
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features ? null,
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}:
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let
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inherit (lib)
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hasAttr getAttr optional optionals optionalString optionalAttrs maintainers platforms;
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# Dependencies that are required to build kernel modules
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moduleBuildDependencies = optional (lib.versionAtLeast version "4.14") libelf;
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installkernel = writeTextFile { name = "installkernel"; executable=true; text = ''
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#!${stdenv.shell} -e
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mkdir -p $4
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cp -av $2 $4
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cp -av $3 $4
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''; };
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commonMakeFlags = [
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"O=$(buildRoot)"
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] ++ lib.optionals (stdenv.hostPlatform.linux-kernel ? makeFlags)
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stdenv.hostPlatform.linux-kernel.makeFlags;
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drvAttrs = config_: kernelConf: kernelPatches: configfile:
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let
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config = let attrName = attr: "CONFIG_" + attr; in {
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isSet = attr: hasAttr (attrName attr) config;
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getValue = attr: if config.isSet attr then getAttr (attrName attr) config else null;
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isYes = attr: (config.getValue attr) == "y";
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isNo = attr: (config.getValue attr) == "n";
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isModule = attr: (config.getValue attr) == "m";
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isEnabled = attr: (config.isModule attr) || (config.isYes attr);
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isDisabled = attr: (!(config.isSet attr)) || (config.isNo attr);
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} // config_;
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isModular = config.isYes "MODULES";
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installsFirmware = (config.isEnabled "FW_LOADER") &&
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(isModular || (config.isDisabled "FIRMWARE_IN_KERNEL")) &&
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(lib.versionOlder version "4.14");
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in (optionalAttrs isModular { outputs = [ "out" "dev" ]; }) // {
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passthru = {
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inherit version modDirVersion config kernelPatches configfile
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moduleBuildDependencies stdenv;
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inherit isZen isHardened isLibre;
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isXen = lib.warn "The isXen attribute is deprecated. All Nixpkgs kernels that support it now have Xen enabled." true;
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kernelOlder = lib.versionOlder version;
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kernelAtLeast = lib.versionAtLeast version;
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};
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inherit src;
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patches =
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map (p: p.patch) kernelPatches
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# Required for deterministic builds along with some postPatch magic.
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++ optional (lib.versionAtLeast version "4.13") ./randstruct-provide-seed.patch
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# Fixes determinism by normalizing metadata for the archive of kheaders
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++ optional (lib.versionAtLeast version "5.2" && lib.versionOlder version "5.4") ./gen-kheaders-metadata.patch;
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prePatch = ''
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for mf in $(find -name Makefile -o -name Makefile.include -o -name install.sh); do
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echo "stripping FHS paths in \`$mf'..."
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sed -i "$mf" -e 's|/usr/bin/||g ; s|/bin/||g ; s|/sbin/||g'
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done
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sed -i Makefile -e 's|= depmod|= ${buildPackages.kmod}/bin/depmod|'
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# Don't include a (random) NT_GNU_BUILD_ID, to make the build more deterministic.
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# This way kernels can be bit-by-bit reproducible depending on settings
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# (e.g. MODULE_SIG and SECURITY_LOCKDOWN_LSM need to be disabled).
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# See also https://kernelnewbies.org/BuildId
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sed -i Makefile -e 's|--build-id=[^ ]*|--build-id=none|'
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patchShebangs scripts
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'';
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postPatch = ''
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# Set randstruct seed to a deterministic but diversified value. Note:
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# we could have instead patched gen-random-seed.sh to take input from
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# the buildFlags, but that would require also patching the kernel's
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# toplevel Makefile to add a variable export. This would be likely to
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# cause future patch conflicts.
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if [ -f scripts/gcc-plugins/gen-random-seed.sh ]; then
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substituteInPlace scripts/gcc-plugins/gen-random-seed.sh \
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--replace NIXOS_RANDSTRUCT_SEED \
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$(echo ${randstructSeed}${src} ${configfile} | sha256sum | cut -d ' ' -f 1 | tr -d '\n')
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fi
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'';
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configurePhase = ''
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runHook preConfigure
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mkdir build
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export buildRoot="$(pwd)/build"
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echo "manual-config configurePhase buildRoot=$buildRoot pwd=$PWD"
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if [ -f "$buildRoot/.config" ]; then
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echo "Could not link $buildRoot/.config : file exists"
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exit 1
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fi
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ln -sv ${configfile} $buildRoot/.config
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# reads the existing .config file and prompts the user for options in
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# the current kernel source that are not found in the file.
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make $makeFlags "''${makeFlagsArray[@]}" oldconfig
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runHook postConfigure
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make $makeFlags "''${makeFlagsArray[@]}" prepare
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actualModDirVersion="$(cat $buildRoot/include/config/kernel.release)"
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if [ "$actualModDirVersion" != "${modDirVersion}" ]; then
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echo "Error: modDirVersion ${modDirVersion} specified in the Nix expression is wrong, it should be: $actualModDirVersion"
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exit 1
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fi
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# Note: we can get rid of this once http://permalink.gmane.org/gmane.linux.kbuild.devel/13800 is merged.
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buildFlagsArray+=("KBUILD_BUILD_TIMESTAMP=$(date -u -d @$SOURCE_DATE_EPOCH)")
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cd $buildRoot
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'';
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buildFlags = [
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"KBUILD_BUILD_VERSION=1-NixOS"
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kernelConf.target
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"vmlinux" # for "perf" and things like that
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]
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++ optional isModular "modules"
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++ extraMakeFlags;
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installFlags = [
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"INSTALLKERNEL=${installkernel}"
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"INSTALL_PATH=$(out)"
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] ++ (optional isModular "INSTALL_MOD_PATH=$(out)")
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++ optional installsFirmware "INSTALL_FW_PATH=$(out)/lib/firmware";
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preInstall = ''
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installFlagsArray+=("-j$NIX_BUILD_CORES")
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'';
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# Some image types need special install targets (e.g. uImage is installed with make uinstall)
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installTargets = [
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(kernelConf.installTarget or (
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/**/ if kernelConf.target == "uImage" then "uinstall"
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else if kernelConf.target == "zImage" || kernelConf.target == "Image.gz" then "zinstall"
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else "install"))
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];
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postInstall = (optionalString installsFirmware ''
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mkdir -p $out/lib/firmware
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'') + (if (kernelConf.DTB or false) then ''
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make $makeFlags "''${makeFlagsArray[@]}" dtbs dtbs_install INSTALL_DTBS_PATH=$out/dtbs
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'' else "") + (if isModular then ''
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mkdir -p $dev
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cp vmlinux $dev/
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if [ -z "''${dontStrip-}" ]; then
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installFlagsArray+=("INSTALL_MOD_STRIP=1")
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fi
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make modules_install $makeFlags "''${makeFlagsArray[@]}" \
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$installFlags "''${installFlagsArray[@]}"
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unlink $out/lib/modules/${modDirVersion}/build
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unlink $out/lib/modules/${modDirVersion}/source
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mkdir -p $dev/lib/modules/${modDirVersion}/{build,source}
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# To save space, exclude a bunch of unneeded stuff when copying.
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(cd .. && rsync --archive --prune-empty-dirs \
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--exclude='/build/' \
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* $dev/lib/modules/${modDirVersion}/source/)
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cd $dev/lib/modules/${modDirVersion}/source
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cp $buildRoot/{.config,Module.symvers} $dev/lib/modules/${modDirVersion}/build
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make modules_prepare $makeFlags "''${makeFlagsArray[@]}" O=$dev/lib/modules/${modDirVersion}/build
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# For reproducibility, removes accidental leftovers from a `cc1` call
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# from a `try-run` call from the Makefile
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rm -f $dev/lib/modules/${modDirVersion}/build/.[0-9]*.d
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# Keep some extra files on some arches (powerpc, aarch64)
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for f in arch/powerpc/lib/crtsavres.o arch/arm64/kernel/ftrace-mod.o; do
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if [ -f "$buildRoot/$f" ]; then
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cp $buildRoot/$f $dev/lib/modules/${modDirVersion}/build/$f
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fi
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done
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# !!! No documentation on how much of the source tree must be kept
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# If/when kernel builds fail due to missing files, you can add
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# them here. Note that we may see packages requiring headers
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# from drivers/ in the future; it adds 50M to keep all of its
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# headers on 3.10 though.
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chmod u+w -R ..
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arch=$(cd $dev/lib/modules/${modDirVersion}/build/arch; ls)
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# Remove unused arches
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for d in $(cd arch/; ls); do
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if [ "$d" = "$arch" ]; then continue; fi
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if [ "$arch" = arm64 ] && [ "$d" = arm ]; then continue; fi
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rm -rf arch/$d
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done
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# Remove all driver-specific code (50M of which is headers)
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rm -fR drivers
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# Keep all headers
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find . -type f -name '*.h' -print0 | xargs -0 -r chmod u-w
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# Keep linker scripts (they are required for out-of-tree modules on aarch64)
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find . -type f -name '*.lds' -print0 | xargs -0 -r chmod u-w
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# Keep root and arch-specific Makefiles
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chmod u-w Makefile
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chmod u-w arch/$arch/Makefile*
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# Keep whole scripts dir
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chmod u-w -R scripts
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# Delete everything not kept
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find . -type f -perm -u=w -print0 | xargs -0 -r rm
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# Delete empty directories
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find -empty -type d -delete
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# Remove reference to kmod
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sed -i Makefile -e 's|= ${buildPackages.kmod}/bin/depmod|= depmod|'
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'' else optionalString installsFirmware ''
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make firmware_install $makeFlags "''${makeFlagsArray[@]}" \
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$installFlags "''${installFlagsArray[@]}"
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'');
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requiredSystemFeatures = [ "big-parallel" ];
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meta = {
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description =
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"The Linux kernel" +
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(if kernelPatches == [] then "" else
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" (with patches: "
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+ lib.concatStringsSep ", " (map (x: x.name) kernelPatches)
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+ ")");
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license = lib.licenses.gpl2Only;
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homepage = "https://www.kernel.org/";
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repositories.git = "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git";
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maintainers = [
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maintainers.thoughtpolice
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];
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platforms = platforms.linux;
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timeout = 14400; # 4 hours
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} // extraMeta;
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};
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in
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assert (lib.versionAtLeast version "4.14" && lib.versionOlder version "5.8") -> libelf != null;
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assert lib.versionAtLeast version "5.8" -> elfutils != null;
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stdenv.mkDerivation ((drvAttrs config stdenv.hostPlatform.linux-kernel kernelPatches configfile) // {
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pname = "linux";
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inherit version;
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enableParallelBuilding = true;
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depsBuildBuild = [ buildPackages.stdenv.cc ];
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nativeBuildInputs = [ perl bc nettools openssl rsync gmp libmpc mpfr gawk zstd python3Minimal ]
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++ optional (stdenv.hostPlatform.linux-kernel.target == "uImage") buildPackages.ubootTools
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++ optional (lib.versionAtLeast version "4.14" && lib.versionOlder version "5.8") libelf
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# Removed util-linuxMinimal since it should not be a dependency.
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++ optionals (lib.versionAtLeast version "4.16") [ bison flex ]
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++ optionals (lib.versionAtLeast version "5.2") [ cpio pahole ]
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++ optional (lib.versionAtLeast version "5.8") elfutils
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;
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buildInputs = optional (lib.versionAtLeast version "5.2") zlib;
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hardeningDisable = [ "bindnow" "format" "fortify" "stackprotector" "pic" "pie" ];
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# Absolute paths for compilers avoid any PATH-clobbering issues.
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makeFlags = commonMakeFlags ++ [
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"CC=${stdenv.cc}/bin/${stdenv.cc.targetPrefix}cc"
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"HOSTCC=${buildPackages.stdenv.cc}/bin/${buildPackages.stdenv.cc.targetPrefix}cc"
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"ARCH=${stdenv.hostPlatform.linuxArch}"
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] ++ lib.optional (stdenv.hostPlatform != stdenv.buildPlatform) [
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"CROSS_COMPILE=${stdenv.cc.targetPrefix}"
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] ++ extraMakeFlags;
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karch = stdenv.hostPlatform.linuxArch;
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})
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