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

Masahiro Yamada
2024-10-23T14:28:57Z

On Wed, Oct 23, 2024 at 10:06 PM Ron Economos <re@w6rz.net> wrote:
>
> On 10/22/24 11:16 AM, Masahiro Yamada wrote:
> > 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
> > .
>
> Tested with option 2 for RISC-V. On Ubuntu 24.04, the following must be
> added to the file /etc/apt/sources.list.d/ubuntu.sources for apt update
> to fetch the correct repositories:
>
> Types: deb
> URIs: http://ports.ubuntu.com/ubuntu-ports
> Suites: noble noble-updates noble-backports
> Components: main universe restricted multiverse
> Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg
> Architectures: riscv64

Right, this is an annoyance of Ubuntu.

x86 and non-x86 architectures use different repositories.

>
> Then:
>
> sudo dpkg --add-architecture riscv64
> sudo apt-get update
> sudo apt-get install libssl-dev:riscv64
>
> The tool chain at https://github.com/riscv-collab/riscv-gnu-toolchain
> can also be made to work. See:
>
> https://github.com/riscv-collab/riscv-gnu-toolchain/issues/1590

You can use any toolchain.

The linux-headers package is rebuilt with riscv64-linux-gnu-gcc,
not your own toolchain.

> Tested-by: Ron Economos <re@w6rz.net>
>
>

--
Best Regards
Masahiro Yamada