[PATCH 2/3] kbuild: deb-pkg: add pkg.linux-upstream.nokernelheaders build profile

Masahiro Yamada
2024-10-22T18:17:15Z

Since commit f1d87664b82a ("kbuild: cross-compile linux-headers package
when possible"), 'make bindeb-pkg' may attempt to cross-compile the
linux-headers package, but it fails under certain circumstances.

For example, when CONFIG_MODULE_SIG_FORMAT is enabled on Debian, the
following command fails:

$ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- bindeb-pkg
[ snip ]
Rebuilding host programs with aarch64-linux-gnu-gcc...
HOSTCC debian/linux-headers-6.12.0-rc4/usr/src/linux-headers-6.12.0-rc4/scripts/kallsyms
HOSTCC debian/linux-headers-6.12.0-rc4/usr/src/linux-headers-6.12.0-rc4/scripts/sorttable
HOSTCC debian/linux-headers-6.12.0-rc4/usr/src/linux-headers-6.12.0-rc4/scripts/asn1_compiler
HOSTCC debian/linux-headers-6.12.0-rc4/usr/src/linux-headers-6.12.0-rc4/scripts/sign-file
In file included from /usr/include/openssl/opensslv.h:109,
from debian/linux-headers-6.12.0-rc4/usr/src/linux-headers-6.12.0-rc4/scripts/sign-file.c:25:
/usr/include/openssl/macros.h:14:10: fatal error: openssl/opensslconf.h: No such file or directory
14 | #include <openssl/opensslconf.h>
| ^~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.

This commit adds a new profile, pkg.linux-upstream.nokernelheaders, to
guard the linux-headers package.

There are two options to fix the above issue.

[option 1] Set the pkg.linux-upstream.nokernelheaders build profile

$ DEB_BUILD_PROFILES=pkg.linux-upstream.nokernelheaders \
make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- bindeb-pkg

This skips the building of the linux-headers package.

[option 2] Install the necessary build dependencies

If you want to cross-compile the linux-headers package, you need to
install additional packages. This is a one-time installation step.

For example, on Debian, the packages necessary for cross-compiling it
to arm64 can be installed with the following commands:

# dpkg --add-architecture arm64
# apt update
# apt install gcc-aarch64-linux-gnu libssl-dev:arm64

Fixes: f1d87664b82a ("kbuild: cross-compile linux-headers package when possible")
Reported-by: Ron Economos <re@w6rz.net>
Closes: https://lore.kernel.org/all/b3d4f49e-7ddb-29ba-0967-689232329b53@w6rz.net/
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

scripts/package/builddeb | 2 +-
scripts/package/install-extmod-build | 6 ++----
scripts/package/mkdebian | 9 ++++++++-
3 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/scripts/package/builddeb b/scripts/package/builddeb
index 404587fc71fe..441b0bb66e0d 100755
--- a/scripts/package/builddeb
+++ b/scripts/package/builddeb
@@ -123,7 +123,7 @@ install_kernel_headers () {
pdir=debian/$1
version=${1#linux-headers-}

- "${srctree}/scripts/package/install-extmod-build" "${pdir}/usr/src/linux-headers-${version}"
+ CC="${DEB_HOST_GNU_TYPE}-gcc" "${srctree}/scripts/package/install-extmod-build" "${pdir}/usr/src/linux-headers-${version}"

mkdir -p $pdir/lib/modules/$version/
ln -s /usr/src/linux-headers-$version $pdir/lib/modules/$version/build
diff --git a/scripts/package/install-extmod-build b/scripts/package/install-extmod-build
index d2c9cacecc0c..7ec1f061a519 100755
--- a/scripts/package/install-extmod-build
+++ b/scripts/package/install-extmod-build
@@ -44,13 +44,11 @@ mkdir -p "${destdir}"
fi
} | tar -c -f - -T - | tar -xf - -C "${destdir}"

-# When ${CC} and ${HOSTCC} differ, we are likely cross-compiling. Rebuild host
-# programs using ${CC}. This assumes CC=${CROSS_COMPILE}gcc, which is usually
-# the case for package building. It does not cross-compile when CC=clang.
+# When ${CC} and ${HOSTCC} differ, rebuild host programs using ${CC}.
#
# This caters to host programs that participate in Kbuild. objtool and
# resolve_btfids are out of scope.
-if [ "${CC}" != "${HOSTCC}" ] && is_enabled CONFIG_CC_CAN_LINK; then
+if [ "${CC}" != "${HOSTCC}" ]; then
echo "Rebuilding host programs with ${CC}..."

cat <<-'EOF' > "${destdir}/Kbuild"
diff --git a/scripts/package/mkdebian b/scripts/package/mkdebian
index 10637d403777..93eb50356ddb 100755
--- a/scripts/package/mkdebian
+++ b/scripts/package/mkdebian
@@ -179,6 +179,8 @@ fi

echo $debarch > debian/arch

+host_gnu=$(dpkg-architecture -a "${debarch}" -q DEB_HOST_GNU_TYPE | sed 's/_/-/g')
+
# Generate a simple changelog template
cat <<EOF > debian/changelog
$sourcename ($packageversion) $distribution; urgency=low
@@ -196,7 +198,11 @@ Priority: optional
Maintainer: $maintainer
Rules-Requires-Root: no
Build-Depends: debhelper-compat (= 12)
-Build-Depends-Arch: bc, bison, cpio, flex, kmod, libelf-dev:native, libssl-dev:native, rsync
+Build-Depends-Arch: bc, bison, cpio, flex,
+ gcc-${host_gnu} <!pkg.${sourcename}.nokernelheaders>,
+ kmod, libelf-dev:native,
+ libssl-dev:native, libssl-dev <!pkg.${sourcename}.nokernelheaders>,
+ rsync
Homepage: https://www.kernel.org/

Package: $packagename-$version
@@ -224,6 +230,7 @@ cat <<EOF >> debian/control

Package: linux-headers-$version
Architecture: $debarch
+Build-Profiles: <!pkg.${sourcename}.nokernelheaders>
Description: Linux kernel headers for $version on $debarch
This package provides kernel header files for $version on $debarch
.
--
2.43.0