Since commit 13b25489b6 ("kbuild: change working directory to external
module directory with M="), the Debian package build fails if a relative
path is specified with the O= option.
$ make O=build bindeb-pkg
[ snip ]
dpkg-deb: building package 'linux-image-6.13.0-rc1' in '../linux-image-6.13.0-rc1_6.13.0-rc1-6_amd64.deb'.
Rebuilding host programs with x86_64-linux-gnu-gcc...
make[6]: Entering directory '/home/masahiro/linux/build'
/home/masahiro/linux/Makefile:190: *** specified kernel directory "build" does not exist. Stop.
This occurs because the sub_make_done flag is cleared, even though the
working directory is already in the output directory.
Passing KBUILD_OUTPUT=. resolves the issue.
Fixes: 13b25489b6 ("kbuild: change working directory to external module directory with M=")
Reported-by: Charlie Jenkins <charlie@rivosinc.com>
Closes: https://lore.kernel.org/all/Z1DnP-GJcfseyrM3@ghost/
Tested-by: Charlie Jenkins <charlie@rivosinc.com>
Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Currently, Kbuild always operates in the output directory of the kernel,
even when building external modules. This increases the risk of external
module Makefiles attempting to write to the kernel directory.
This commit switches the working directory to the external module
directory, allowing the removal of the $(KBUILD_EXTMOD)/ prefix from
some build artifacts.
The command for building external modules maintains backward
compatibility, but Makefiles that rely on working in the kernel
directory may break. In such cases, $(objtree) and $(srctree) should
be used to refer to the output and source directories of the kernel.
The appearance of the build log will change as follows:
[Before]
$ make -C /path/to/my/linux M=/path/to/my/externel/module
make: Entering directory '/path/to/my/linux'
CC [M] /path/to/my/externel/module/helloworld.o
MODPOST /path/to/my/externel/module/Module.symvers
CC [M] /path/to/my/externel/module/helloworld.mod.o
CC [M] /path/to/my/externel/module/.module-common.o
LD [M] /path/to/my/externel/module/helloworld.ko
make: Leaving directory '/path/to/my/linux'
[After]
$ make -C /path/to/my/linux M=/path/to/my/externel/module
make: Entering directory '/path/to/my/linux'
make[1]: Entering directory '/path/to/my/externel/module'
CC [M] helloworld.o
MODPOST Module.symvers
CC [M] helloworld.mod.o
CC [M] .module-common.o
LD [M] helloworld.ko
make[1]: Leaving directory '/path/to/my/externel/module'
make: Leaving directory '/path/to/my/linux'
Printing "Entering directory" twice is cumbersome. This will be
addressed later.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
Since commit f1d87664b8 ("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.
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: f1d87664b8 ("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>
Tested-by: Ron Economos <re@w6rz.net>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
A long standing issue in the upstream kernel packaging is that the
linux-headers package is not cross-compiled.
For example, you can cross-build Debian packages for arm64 by running
the following command:
$ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- bindeb-pkg
However, the generated linux-headers-*_arm64.deb is useless because the
host programs in it were built for your build machine architecture
(likely x86), not arm64.
The Debian kernel maintains its own Makefiles to cross-compile host
tools without relying on Kbuild. [1]
Instead of adding such full custom Makefiles, this commit adds a small
piece of code to cross-compile host programs located under the scripts/
directory.
A straightforward solution is to pass HOSTCC=${CROSS_COMPILE}gcc, but it
would also cross-compile scripts/basic/fixdep, which needs to be native
to process the if_changed_dep macro. (This approach may work under some
circumstances; you can execute foreign architecture programs with the
help of binfmt_misc because Debian systems enable CONFIG_BINFMT_MISC,
but it would require installing QEMU and libc for that architecture.)
A trick is to use the external module build (KBUILD_EXTMOD=), which
does not rebuild scripts/basic/fixdep. ${CC} needs to be able to link
userspace programs (CONFIG_CC_CAN_LINK=y).
There are known limitations:
- GCC plugins
It would possible to rebuild GCC plugins for the target architecture
by passing HOSTCXX=${CROSS_COMPILE}g++ with necessary packages
installed, but gcc on the installed system emits
"cc1: error: incompatible gcc/plugin versions".
- objtool and resolve_btfids
These are built by the tools build system. They are not covered by
the current solution. The resulting linux-headers package is broken
if CONFIG_OBJTOOL or CONFIG_DEBUG_INFO_BTF is enabled.
I only tested this with Debian, but it should work for other package
systems as well.
[1]: https://salsa.debian.org/kernel-team/linux/-/blob/debian/6.9.9-1/debian/rules.real#L586
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Set -e to make these scripts fail on the first error.
Set -u because these scripts are invoked by Makefile, and do not work
properly without necessary variables defined.
I tweaked mkdebian to cope with optional environment variables.
Remove the explicit "test -n ..." from install-extmod-build.
Both options are described in POSIX. [1]
[1]: https://pubs.opengroup.org/onlinepubs/009604499/utilities/set.html
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
The 'scripts' directory was searched under arch/${SRCARCH} to copy
arch/ia64/scripts, but commit cf8e865810 ("arch: Remove Itanium
(IA-64) architecture") removed arch/ia64/ entirely.
There is another 'scripts' directory in arch/um/, but this script
is never executed with SRCARCH=um because UML does not support the
linux-headers package.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Since commit fe66b5d2ae ("kbuild: refactor kernel-devel RPM package
and linux-headers Deb package"), the kernel-devel RPM package and
linux-headers Deb package are broken.
I double-quoted the $(find ... -type d), which resulted in newlines
being included in the argument to the outer find comment.
find: 'arch/arm64/include\narch/arm64/kvm/hyp/include': No such file or directory
The outer find command is unneeded.
Fixes: fe66b5d2ae ("kbuild: refactor kernel-devel RPM package and linux-headers Deb package")
Reported-by: Karolis M <k4rolis@protonmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
The kernel-devel RPM package and the linux-headers Debian package
provide headers and scripts needed for building external modules.
They copy the necessary files in slightly different ways - the RPM
copies almost everything except some exclude patterns, while the Debian
copies less number of files. There is no need to maintain different code
to do the same thing.
Split the Debian code out to scripts/package/install-extmod-build, which
is called from both of the packages.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
