Earlier attempts to get "make O=build kselftest-all" to work were not successful as they made undesirable changes to some functions in the top-level Makefile. This series takes a different approach by removing the root cause of the problem within kselftest, which is when the sub-Makefile tries to install kernel headers "backwards" by calling make with the top-level Makefile. The actual issue comes from the fact that $(srctree) is ".." when building in a sub-directory with "O=build" which then obviously makes "-C $(top_srcdir)" point outside of the real source tree.
With this series, the generic kselftest targets work as expected from the top level with or without a build directory e.g.:
$ make kselftest-all
$ make O=build kselftest-all
Then in order to build using the sub-Makefile explicitly, the headers have to be installed first. This is arguably a valid requirement to have when building a tool from a sub-Makefile. For example, "make -C tools/testing/nvdimm/" fails in a similar way until <asm/rwonce.h> has been generated by a kernel build.
v2: replace headers_install with headers
Guillaume Tucker (4): selftests: drop khdr make target selftests: stop using KSFT_KHDR_INSTALL selftests: drop KSFT_KHDR_INSTALL make target Makefile: add headers to kselftest targets
Makefile | 4 +- tools/testing/selftests/Makefile | 28 +------------- tools/testing/selftests/arm64/mte/Makefile | 1 - tools/testing/selftests/arm64/signal/Makefile | 1 - .../selftests/arm64/signal/test_signals.h | 4 +- .../selftests/drivers/s390x/uvdevice/Makefile | 1 - .../selftests/futex/functional/Makefile | 1 - tools/testing/selftests/kvm/Makefile | 1 - tools/testing/selftests/landlock/Makefile | 1 - tools/testing/selftests/lib.mk | 38 ------------------- tools/testing/selftests/net/Makefile | 1 - tools/testing/selftests/net/mptcp/Makefile | 1 - tools/testing/selftests/tc-testing/Makefile | 1 - tools/testing/selftests/vm/Makefile | 1 - 14 files changed, 5 insertions(+), 79 deletions(-)
-- 2.30.2