selftests: Add headers target

Some selftests need access to a full UAPI headers tree, for example when
building with nolibc which heavily relies on UAPI headers.
A reference to such a tree is availa

selftests: Add headers target

Some selftests need access to a full UAPI headers tree, for example when
building with nolibc which heavily relies on UAPI headers.
A reference to such a tree is available in the KHDR_INCLUDES variable,
but there is currently no way to populate such a tree automatically.

Provide a target that the tests can depend on to get access to usable
UAPI headers.

Signed-off-by: Thomas Weißschuh <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Vincenzo Frascino <[email protected]>
Acked-by: Shuah Khan <[email protected]>
Link: https://lore.kernel.org/all/[email protected]

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selftests/lib.mk: silence some clang warnings that gcc already ignores

gcc defaults to silence (off) for the following warnings, but clang
defaults to the opposite. The warnings are not useful for t

selftests/lib.mk: silence some clang warnings that gcc already ignores

gcc defaults to silence (off) for the following warnings, but clang
defaults to the opposite. The warnings are not useful for the kernel
itself, which is why they have remained disabled in gcc for the main
kernel build. And it is only due to including kernel data structures in
the selftests, that we get the warnings from clang.

-Waddress-of-packed-member
-Wgnu-variable-sized-type-not-at-end

In other words, the warnings are not unique to the selftests: there is
nothing that the selftests' code does that triggers these warnings,
other than the act of including the kernel's data structures. Therefore,
silence them for the clang builds as well.

This eliminates warnings for the net/ and user_events/ kselftest
subsystems, in these files:

./net/af_unix/scm_rights.c
./net/timestamping.c
./net/ipsec.c
./user_events/perf_test.c

Cc: Nathan Chancellor <[email protected]>
Signed-off-by: John Hubbard <[email protected]>
Acked-by: Nathan Chancellor <[email protected]>
Signed-off-by: Shuah Khan <[email protected]>

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selftests: centralize -D_GNU_SOURCE= to CFLAGS in lib.mk

Centralize the _GNU_SOURCE definition to CFLAGS in lib.mk. Remove
redundant defines from Makefiles that import lib.mk. Convert any usage of

selftests: centralize -D_GNU_SOURCE= to CFLAGS in lib.mk

Centralize the _GNU_SOURCE definition to CFLAGS in lib.mk. Remove
redundant defines from Makefiles that import lib.mk. Convert any usage of
"#define _GNU_SOURCE 1" to "#define _GNU_SOURCE".

This uses the form "-D_GNU_SOURCE=", which is equivalent to
"#define _GNU_SOURCE".

Otherwise using "-D_GNU_SOURCE" is equivalent to "-D_GNU_SOURCE=1" and
"#define _GNU_SOURCE 1", which is less commonly seen in source code and
would require many changes in selftests to avoid redefinition warnings.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Edward Liaw <[email protected]>
Suggested-by: John Hubbard <[email protected]>
Acked-by: Shuah Khan <[email protected]>
Reviewed-by: Muhammad Usama Anjum <[email protected]>
Cc: Albert Ou <[email protected]>
Cc: André Almeida <[email protected]>
Cc: Darren Hart <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: David S. Miller <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: Eric W. Biederman <[email protected]>
Cc: Fenghua Yu <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jakub Kicinski <[email protected]>
Cc: Jarkko Sakkinen <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Kevin Tian <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Paolo Abeni <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Reinette Chatre <[email protected]>
Cc: Sean Christopherson <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

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Revert "selftests: Compile kselftest headers with -D_GNU_SOURCE"

This reverts commit daef47b89efd0b745e8478d69a3ad724bd8b4dc6.

This framework change to add D_GNU_SOURCE to KHDR_INCLUDES
to Makefile

Revert "selftests: Compile kselftest headers with -D_GNU_SOURCE"

This reverts commit daef47b89efd0b745e8478d69a3ad724bd8b4dc6.

This framework change to add D_GNU_SOURCE to KHDR_INCLUDES
to Makefile, lib.mk, and kselftest_harness.h is causing build
failures and warnings.

Revert this change.

Reported-by: Mark Brown <[email protected]>
Signed-off-by: Shuah Khan <[email protected]>

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selftests: Compile kselftest headers with -D_GNU_SOURCE

Add the -D_GNU_SOURCE flag to KHDR_INCLUDES so that it is defined in a
central location.

Commit 809216233555 ("selftests/harness: remove use

selftests: Compile kselftest headers with -D_GNU_SOURCE

Add the -D_GNU_SOURCE flag to KHDR_INCLUDES so that it is defined in a
central location.

Commit 809216233555 ("selftests/harness: remove use of LINE_MAX")
introduced asprintf into kselftest_harness.h, which is a GNU extension
and needs _GNU_SOURCE to either be defined prior to including headers or
with the -D_GNU_SOURCE flag passed to the compiler.

Fixed up commit log:
Shuah Khan <[email protected]>

Fixes: 809216233555 ("selftests/harness: remove use of LINE_MAX")
Reported-by: kernel test robot <[email protected]>
Closes: https://lore.kernel.org/oe-lkp/[email protected]
Signed-off-by: Edward Liaw <[email protected]>
Reviewed-by: Muhammad Usama Anjum <[email protected]>
Reviewed-by: Mark Brown <[email protected]>
Reviewed-by: John Hubbard <[email protected]>
Signed-off-by: Shuah Khan <[email protected]>

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selftests: default to host arch for LLVM builds

Align the behavior for gcc and clang builds by interpreting unset
`ARCH` and `CROSS_COMPILE` variables in `LLVM` builds as a sign that the
user wants

selftests: default to host arch for LLVM builds

Align the behavior for gcc and clang builds by interpreting unset
`ARCH` and `CROSS_COMPILE` variables in `LLVM` builds as a sign that the
user wants to build for the host architecture.

This patch preserves the properties that setting the `ARCH` variable to an
unknown value will trigger an error that complains about insufficient
information, and that a set `CROSS_COMPILE` variable will override the
target triple that is determined based on presence/absence of `ARCH`.

When compiling with clang, i.e., `LLVM` is set, an unset `ARCH` variable in
combination with an unset `CROSS_COMPILE` variable, i.e., compiling for
the host architecture, leads to compilation failures since `lib.mk` can
not determine the clang target triple. In this case, the following error
message is displayed for each subsystem that does not set `ARCH` in its
own Makefile before including `lib.mk` (lines wrapped at 75 chrs):

make[1]: Entering directory '/mnt/build/linux/tools/testing/selftests/
sysctl'
../lib.mk:33: *** Specify CROSS_COMPILE or add '--target=' option to
lib.mk. Stop.
make[1]: Leaving directory '/mnt/build/linux/tools/testing/selftests/
sysctl'

In the same scenario a gcc build would default to the host architecture,
i.e., it would use plain `gcc`.

Fixes: 795285ef2425 ("selftests: Fix clang cross compilation")
Reviewed-by: Mark Brown <[email protected]>
Signed-off-by: Valentin Obst <[email protected]>
Reviewed-by: John Hubbard <[email protected]>
Signed-off-by: Shuah Khan <[email protected]>

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selftests: break the dependency upon local header files

Patch series "Fix selftests/mm build without requiring "make headers"".

As mentioned in each patch, this implements the solution that we disc

selftests: break the dependency upon local header files

Patch series "Fix selftests/mm build without requiring "make headers"".

As mentioned in each patch, this implements the solution that we discussed
in December 2023, in [1]. This turned out to be very clean and easy. It
should also be quite easy to maintain.

This should also make Peter Zijlstra happy, because it directly addresses
the root cause of his "NAK NAK NAK" reply [2]. :)

[1] https://lore.kernel.org/all/[email protected]/
[2] https://lore.kernel.org/lkml/[email protected]/


This patch (of 2):

Use tools/include/uapi/ files instead. These are obtained by taking a
snapshot: run "make headers" at the top level, then copy the desired
header file into the appropriate subdir in tools/uapi/.

This was discussed and solved in [1].

However, even before copying any additional files there, there are already
quite a few in tools/include/uapi already. And these will immediately fix
a number of selftests/mm build failures.

So this patch:

a) Adds TOOLS_INCLUDES to selftests/lib.mk, so that all selftests can
immediately and easily include the snapshotted header files.

b) Uses $(TOOLS_INCLUDES) in the selftests/mm build. On today's Arch
Linux, this already fixes all build errors except for a few
userfaultfd.h (those will be addressed in a subsequent patch).

[1] https://lore.kernel.org/all/[email protected]/

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: John Hubbard <[email protected]>
Acked-by: David Hildenbrand <[email protected]>
Cc: Mark Brown <[email protected]>
Cc: Muhammad Usama Anjum <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: Axel Rasmussen <[email protected]>
Cc: Peter Xu <[email protected]>
Cc: Shuah Khan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

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selftests: adopt BPF's approach to quieter builds

selftest build is fairly noisy, it's easy to miss warnings.
It's standard practice to add alternative messages in
the Makefile. I was grepping for e

selftests: adopt BPF's approach to quieter builds

selftest build is fairly noisy, it's easy to miss warnings.
It's standard practice to add alternative messages in
the Makefile. I was grepping for existing solutions,
and found that bpf already has the right knobs.

Move them to lib.mk and adopt in net.
Convert the basic rules in lib.mk.

Acked-by: Daniel Borkmann <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

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selftests: lib.mk: Do not process TEST_GEN_MODS_DIR

The directory itself doesn't need have path handling, since it's only to
mean where is the directory that contains modules to be built.

Signed-of

selftests: lib.mk: Do not process TEST_GEN_MODS_DIR

The directory itself doesn't need have path handling, since it's only to
mean where is the directory that contains modules to be built.

Signed-off-by: Marcos Paulo de Souza <[email protected]>
Signed-off-by: Shuah Khan <[email protected]>

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selftests: Introduce Makefile variable to list shared bash scripts

Some tests written in bash source other files in a parent directory. For
example, drivers/net/bonding/dev_addr_lists.sh sources
net

selftests: Introduce Makefile variable to list shared bash scripts

Some tests written in bash source other files in a parent directory. For
example, drivers/net/bonding/dev_addr_lists.sh sources
net/forwarding/lib.sh. If a subset of tests is exported and run outside the
source tree (for example by using `make -C tools/testing/selftests gen_tar
TARGETS="drivers/net/bonding"`), these other files must be made available
as well.

Commit ae108c48b5d2 ("selftests: net: Fix cross-tree inclusion of scripts")
addressed this problem by symlinking and copying the sourced files but this
only works for direct dependencies. Commit 25ae948b4478 ("selftests/net:
add lib.sh") changed net/forwarding/lib.sh to source net/lib.sh. As a
result, that latter file must be included as well when the former is
exported. This was not handled and was reverted in commit 2114e83381d3
("selftests: forwarding: Avoid failures to source net/lib.sh"). In order to
allow reinstating the inclusion of net/lib.sh from net/forwarding/lib.sh,
add a mechanism to list dependent files in a new Makefile variable and
export them. This allows sourcing those files using the same expression
whether tests are run in-tree or exported.

Dependencies are not resolved recursively so transitive dependencies must
be listed in TEST_INCLUDES. For example, if net/forwarding/lib.sh sources
net/lib.sh; the Makefile related to a test that sources
net/forwarding/lib.sh from a parent directory must list:
TEST_INCLUDES := \
../../../net/forwarding/lib.sh \
../../../net/lib.sh

v2:
Fix rst syntax in Documentation/dev-tools/kselftest.rst (Jakub Kicinski)

v1 (from RFC):
* changed TEST_INCLUDES to take relative paths, like other TEST_* variables
(Vladimir Oltean)
* preserved common "$(MAKE) OUTPUT=... -C ... target" ordering in Makefile
(Petr Machata)

Signed-off-by: Benjamin Poirier <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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kselftests: lib.mk: Add TEST_GEN_MODS_DIR variable

Add TEST_GEN_MODS_DIR variable for kselftests. It can point to
a directory containing kernel modules that will be used by
selftest scripts.

The mo

kselftests: lib.mk: Add TEST_GEN_MODS_DIR variable

Add TEST_GEN_MODS_DIR variable for kselftests. It can point to
a directory containing kernel modules that will be used by
selftest scripts.

The modules are built as external modules for the running kernel.
As a result they are always binary compatible and the same tests
can be used for older or newer kernels.

The build requires "kernel-devel" package to be installed.
For example, in the upstream sources, the rpm devel package
is produced by "make rpm-pkg"

The modules can be built independently by

make -C tools/testing/selftests/livepatch/

or they will be automatically built before running the tests via

make -C tools/testing/selftests/livepatch/ run_tests

Note that they are _not_ built when running the standalone
tests by calling, for example, ./test-state.sh.

Along with TEST_GEN_MODS_DIR, it was necessary to create a new install
rule. INSTALL_MODS_RULE is needed because INSTALL_SINGLE_RULE would
copy the entire TEST_GEN_MODS_DIR directory to the destination, even
the files created by Kbuild to compile the modules. The new install
rule copies only the .ko files, as we would expect the gen_tar to work.

Reviewed-by: Joe Lawrence <[email protected]>
Reviewed-by: Petr Mladek <[email protected]>
Signed-off-by: Marcos Paulo de Souza <[email protected]>
Signed-off-by: Shuah Khan <[email protected]>

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Revert "selftests: error out if kernel header files are not yet built"

This reverts commit 9fc96c7c19df ("selftests: error out if kernel header
files are not yet built").

It turns out that requirin

Revert "selftests: error out if kernel header files are not yet built"

This reverts commit 9fc96c7c19df ("selftests: error out if kernel header
files are not yet built").

It turns out that requiring the kernel headers to be built as a
prerequisite to building selftests, does not work in many cases. For
example, Peter Zijlstra writes:

"My biggest beef with the whole thing is that I simply do not want to use
'make headers', it doesn't work for me.

I have a ton of output directories and I don't care to build tools into
the output dirs, in fact some of them flat out refuse to work that way
(bpf comes to mind)." [1]

Therefore, stop erroring out on the selftests build. Additional patches
will be required in order to change over to not requiring the kernel
headers.

[1] https://lore.kernel.org/[email protected]

Link: https://lkml.kernel.org/r/[email protected]
Fixes: 9fc96c7c19df ("selftests: error out if kernel header files are not yet built")
Signed-off-by: John Hubbard <[email protected]>
Cc: Anders Roxell <[email protected]>
Cc: Muhammad Usama Anjum <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Peter Xu <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Nathan Chancellor <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Marcos Paulo de Souza <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

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selftests: Keep symlinks, when possible

When kselftest is built/installed with the 'gen_tar' target, rsync is
used for the installation step to copy files. Extra care is needed for
tests that have s

selftests: Keep symlinks, when possible

When kselftest is built/installed with the 'gen_tar' target, rsync is
used for the installation step to copy files. Extra care is needed for
tests that have symlinks. Commit ae108c48b5d2 ("selftests: net: Fix
cross-tree inclusion of scripts") added '-L' (transform symlink into
referent file/dir) to rsync, to fix dangling links. However, that
broke some tests where the symlink (being a symlink) is part of the
test (e.g. exec:execveat).

Use rsync's '--copy-unsafe-links' that does right thing.

Fixes: ae108c48b5d2 ("selftests: net: Fix cross-tree inclusion of scripts")
Signed-off-by: Björn Töpel <[email protected]>
Reviewed-by: Benjamin Poirier <[email protected]>
Signed-off-by: Shuah Khan <[email protected]>

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selftests: error out if kernel header files are not yet built

As per a discussion with Muhammad Usama Anjum [1], the following is how
one is supposed to build selftests:

make headers && make -C

selftests: error out if kernel header files are not yet built

As per a discussion with Muhammad Usama Anjum [1], the following is how
one is supposed to build selftests:

make headers && make -C tools/testing/selftests/mm

Change the selftest build system's lib.mk to fail out with a helpful
message if that prerequisite "make headers" has not been done yet.

[1] https://lore.kernel.org/all/[email protected]/

[[email protected]: abort the make process the first time headers aren't detected]
Link: https://lkml.kernel.org/r/[email protected]
[[email protected]: fix out-of-tree builds]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: John Hubbard <[email protected]>
Signed-off-by: Anders Roxell <[email protected]>
Reviewed-by: Muhammad Usama Anjum <[email protected]>
Tested-by: Muhammad Usama Anjum <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Peter Xu <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Nathan Chancellor <[email protected]>
Cc: Shuah Khan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

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selftests: fix LLVM build for i386 and x86_64

Add missing cases for the i386 and x86_64 architectures when
determining the LLVM target for building kselftest.

Fixes: 795285ef2425 ("selftests: Fix c

selftests: fix LLVM build for i386 and x86_64

Add missing cases for the i386 and x86_64 architectures when
determining the LLVM target for building kselftest.

Fixes: 795285ef2425 ("selftests: Fix clang cross compilation")
Signed-off-by: Guillaume Tucker <[email protected]>
Reviewed-by: Nathan Chancellor <[email protected]>
Signed-off-by: Shuah Khan <[email protected]>

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kselftest: Fix error message for unconfigured LLVM builds

We are missing a ) when we attempt to complain about not having enough
configuration for clang, resulting in the rather inscrutable error:

kselftest: Fix error message for unconfigured LLVM builds

We are missing a ) when we attempt to complain about not having enough
configuration for clang, resulting in the rather inscrutable error:

../lib.mk:23: *** unterminated call to function 'error': missing ')'. Stop.

Add the required ) so we print the message we were trying to print.

Signed-off-by: Mark Brown <[email protected]>
Signed-off-by: Shuah Khan <[email protected]>

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selftests: net: Fix cross-tree inclusion of scripts

When exporting and running a subset of selftests via kselftest, files from
parts of the source tree which were not exported are not available. A f

selftests: net: Fix cross-tree inclusion of scripts

When exporting and running a subset of selftests via kselftest, files from
parts of the source tree which were not exported are not available. A few
tests are trying to source such files. Address the problem by using
symlinks.

The problem can be reproduced by running:
make -C tools/testing/selftests gen_tar TARGETS="drivers/net/bonding"
[... extract archive ...]
./run_kselftest.sh

or:
make kselftest KBUILD_OUTPUT=/tmp/kselftests TARGETS="drivers/net/bonding"

Fixes: bbb774d921e2 ("net: Add tests for bonding and team address list management")
Fixes: eccd0a80dc7f ("selftests: net: dsa: add a stress test for unlocked FDB operations")
Link: https://lore.kernel.org/netdev/[email protected]/
Reported-by: Jonathan Toppins <[email protected]>
Signed-off-by: Benjamin Poirier <[email protected]>
Reviewed-by: Jonathan Toppins <[email protected]>
Signed-off-by: Jakub Kicinski <[email protected]>

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selftests: Use optional USERCFLAGS and USERLDFLAGS

This change enables to extend CFLAGS and LDFLAGS from command line, e.g.
to extend compiler checks: make USERCFLAGS=-Werror USERLDFLAGS=-static

US

selftests: Use optional USERCFLAGS and USERLDFLAGS

This change enables to extend CFLAGS and LDFLAGS from command line, e.g.
to extend compiler checks: make USERCFLAGS=-Werror USERLDFLAGS=-static

USERCFLAGS and USERLDFLAGS are documented in
Documentation/kbuild/makefiles.rst and Documentation/kbuild/kbuild.rst

This should be backported (down to 5.10) to improve previous kernel
versions testing as well.

Cc: Shuah Khan <[email protected]>
Cc: [email protected]
Signed-off-by: Mickaël Salaün <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Shuah Khan <[email protected]>

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selftests/landlock: Fix out-of-tree builds

These changes simplify the Makefile and handle these 5 ways to build
Landlock tests:
- make -C tools/testing/selftests/landlock
- make -C tools/testing/sel

selftests/landlock: Fix out-of-tree builds

These changes simplify the Makefile and handle these 5 ways to build
Landlock tests:
- make -C tools/testing/selftests/landlock
- make -C tools/testing/selftests TARGETS=landlock gen_tar
- make TARGETS=landlock kselftest-gen_tar
- make TARGETS=landlock O=build kselftest-gen_tar
- make -C /tmp/linux TARGETS=landlock O=/tmp/build kselftest-gen_tar

This also makes $(KHDR_INCLUDES) available to other test collections
when building in their directory.

Fixes: f1227dc7d041 ("selftests/landlock: fix broken include of linux/landlock.h")
Fixes: 3bb267a36185 ("selftests: drop khdr make target")
Cc: Anders Roxell <[email protected]>
Cc: Guillaume Tucker <[email protected]>
Cc: Mark Brown <[email protected]>
Cc: Shuah Khan <[email protected]>
Signed-off-by: Mickaël Salaün <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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selftests/vm: fix inability to build any vm tests

When we stopped using KSFT_KHDR_INSTALL, a side effect is we also
changed the value of `top_srcdir`. This can be seen by looking at the
code removed

selftests/vm: fix inability to build any vm tests

When we stopped using KSFT_KHDR_INSTALL, a side effect is we also
changed the value of `top_srcdir`. This can be seen by looking at the
code removed by commit 49de12ba06ef
("selftests: drop KSFT_KHDR_INSTALL make target").

(Note though that this commit didn't break this, technically the one
before it did since that's the one that stopped KSFT_KHDR_INSTALL from
being used, even though the code was still there.)

Previously lib.mk reconfigured `top_srcdir` when KSFT_KHDR_INSTALL was
being used. Now, that's no longer the case.

As a result, the path to gup_test.h in vm/Makefile was wrong, and
since it's a dependency of all of the vm binaries none of them could
be built. Instead, we'd get an "error" like:

make[1]: *** No rule to make target
'/[...]/tools/testing/selftests/vm/compaction_test', needed by
'all'. Stop.

So, modify lib.mk so it once again sets top_srcdir to the root of the
kernel tree.

Fixes: f2745dc0ba3d ("selftests: stop using KSFT_KHDR_INSTALL")
Signed-off-by: Axel Rasmussen <[email protected]>
Signed-off-by: Shuah Khan <[email protected]>

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selftests: drop KSFT_KHDR_INSTALL make target

Drop the KSFT_KHDR_INSTALL make target now that all use-cases have
been removed from the other kselftest Makefiles.

Signed-off-by: Guillaume Tucker <gu

selftests: drop KSFT_KHDR_INSTALL make target

Drop the KSFT_KHDR_INSTALL make target now that all use-cases have
been removed from the other kselftest Makefiles.

Signed-off-by: Guillaume Tucker <[email protected]>
Tested-by: Anders Roxell <[email protected]>
Signed-off-by: Shuah Khan <[email protected]>

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selftests: Fix clang cross compilation

Unlike GCC clang uses a single compiler image to support multiple target
architectures meaning that we can't simply rely on CROSS_COMPILE to select
the output

selftests: Fix clang cross compilation

Unlike GCC clang uses a single compiler image to support multiple target
architectures meaning that we can't simply rely on CROSS_COMPILE to select
the output architecture. Instead we must pass --target to the compiler to
tell it what to output, kselftest was not doing this so cross compilation
of kselftest using clang resulted in kselftest being built for the host
architecture.

More work is required to fix tests using custom rules but this gets the
bulk of things building.

Signed-off-by: Mark Brown <[email protected]>
Signed-off-by: Shuah Khan <[email protected]>

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kbuild: Make $(LLVM) more flexible

The LLVM make variable allows a developer to quickly switch between the
GNU and LLVM tools. However, it does not handle versioned binaries, such
as the ones shippe

kbuild: Make $(LLVM) more flexible

The LLVM make variable allows a developer to quickly switch between the
GNU and LLVM tools. However, it does not handle versioned binaries, such
as the ones shipped by Debian, as LLVM=1 just defines the tool variables
with the unversioned binaries.

There was some discussion during the review of the patch that introduces
LLVM=1 around versioned binaries, ultimately coming to the conclusion
that developers can just add the folder that contains the unversioned
binaries to their PATH, as Debian's versioned suffixed binaries are
really just symlinks to the unversioned binaries in /usr/lib/llvm-#/bin:

$ realpath /usr/bin/clang-14
/usr/lib/llvm-14/bin/clang

$ PATH=/usr/lib/llvm-14/bin:$PATH make ... LLVM=1

However, that can be cumbersome to developers who are constantly testing
series with different toolchains and versions. It is simple enough to
support these versioned binaries directly in the Kbuild system by
allowing the developer to specify the version suffix with LLVM=, which
is shorter than the above suggestion:

$ make ... LLVM=-14

It does not change the meaning of LLVM=1 (which will continue to use
unversioned binaries) and it does not add too much additional complexity
to the existing $(LLVM) code, while allowing developers to quickly test
their series with different versions of the whole LLVM suite of tools.

Some developers may build LLVM from source but not add the binaries to
their PATH, as they may not want to use that toolchain systemwide.
Support those developers by allowing them to supply the directory that
the LLVM tools are available in, as it is no more complex to support
than the version suffix change above.

$ make ... LLVM=/path/to/llvm/

Update and reorder the documentation to reflect these new additions.
At the same time, notate that LLVM=0 is not the same as just omitting it
altogether, which has confused people in the past.

Link: https://lore.kernel.org/r/[email protected]/
Link: https://lore.kernel.org/r/[email protected]/
Suggested-by: Masahiro Yamada <[email protected]>
Suggested-by: Peter Zijlstra <[email protected]>
Signed-off-by: Nathan Chancellor <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Reviewed-by: Nick Desaulniers <[email protected]>
Signed-off-by: Masahiro Yamada <[email protected]>

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selftests: cgroup: build error multiple outpt files

When building selftests/cgroup: with clang the following error are seen:

clang -Wall -pthread test_memcontrol.c cgroup_util.c ../clone3/clone3

selftests: cgroup: build error multiple outpt files

When building selftests/cgroup: with clang the following error are seen:

clang -Wall -pthread test_memcontrol.c cgroup_util.c ../clone3/clone3_selftests.h -o .../builds/current/kselftest/cgroup/test_memcontrol
clang: error: cannot specify -o when generating multiple output files
make[3]: *** [../lib.mk:146: .../builds/current/kselftest/cgroup/test_memcontrol] Error 1

Rework to add the header files to LOCAL_HDRS before including ../lib.mk,
since the dependency is evaluated in '$(OUTPUT)/%:%.c $(LOCAL_HDRS)' in
file lib.mk.

Suggested-by: Arnd Bergmann <[email protected]>
Signed-off-by: Anders Roxell <[email protected]>
Acked-by: Christian Brauner <[email protected]>
Signed-off-by: Shuah Khan <[email protected]>

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selftests: be sure to make khdr before other targets

LKP/0Day reported some building errors about kvm, and errors message
are not always same:
- lib/x86_64/processor.c:1083:31: error: ‘KVM_CAP_NESTE

selftests: be sure to make khdr before other targets

LKP/0Day reported some building errors about kvm, and errors message
are not always same:
- lib/x86_64/processor.c:1083:31: error: ‘KVM_CAP_NESTED_STATE’ undeclared
(first use in this function); did you mean ‘KVM_CAP_PIT_STATE2’?
- lib/test_util.c:189:30: error: ‘MAP_HUGE_16KB’ undeclared (first use
in this function); did you mean ‘MAP_HUGE_16GB’?

Although kvm relies on the khdr, they still be built in parallel when -j
is specified. In this case, it will cause compiling errors.

Here we mark target khdr as NOTPARALLEL to make it be always built
first.

CC: Philip Li <[email protected]>
Reported-by: kernel test robot <[email protected]>
Signed-off-by: Li Zhijian <[email protected]>
Signed-off-by: Shuah Khan <[email protected]>

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