Provide an initial test case to evaluate the functionality. This needs to be
extended to cover the ABI violations and expose the race condition between
observing granted and arriving in rseq_slice_yield().

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251215155709.320325431@linutronix.de

This test adds coverage of expected errors during rseq registration and
unregistration, it disables glibc integration and will thus always
exercise the rseq syscall explictly.

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/20250121213402.1754762-1-mjeanson@efficios.com

Pull Kselftest updates from Shuah Khan:
 "A mix of fixes, enhancements, and new tests. Bulk of the changes
  enhance and fix rseq and resctrl tests.

  In addition, user_events, dmabuf-heaps and perf_events are added to
  default kselftest build and test coverage. A futex test fix, enhance
  prctl test coverage, and minor fixes are included in this update"

* tag 'linux-kselftest-next-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: (32 commits)
  selftests: cachestat: use proper syscall number macro
  selftests: cachestat: properly link in librt
  selftests/futex: Order calls to futex_lock_pi
  selftests: Hook more tests into the build infrastructure
  selftests/user_events: Reenable build
  selftests/filesystems: Add six consecutive 'x' characters to mktemp
  selftests/rseq: Use rseq_unqual_scalar_typeof in macros
  selftests/rseq: Fix arm64 buggy load-acquire/store-release macros
  selftests/rseq: Implement rseq_unqual_scalar_typeof
  selftests/rseq: Fix CID_ID typo in Makefile
  selftests:prctl: add set-process-name to .gitignore
  selftests:prctl: Fix make clean override warning
  selftests/resctrl: Remove test type checks from cat_val()
  selftests/resctrl: Pass the real number of tests to show_cache_info()
  selftests/resctrl: Move CAT/CMT test global vars to function they are used in
  selftests/resctrl: Don't use variable argument list for ->setup()
  selftests/resctrl: Don't pass test name to fill_buf
  selftests/resctrl: Improve parameter consistency in fill_buf
  selftests/resctrl: Remove unnecessary startptr global from fill_buf
  selftests/resctrl: Remove "malloc_and_init_memory" param from run_fill_buf()
  ...

Ensure that the basic percpu ops tests are effectively built against
mm_cid.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Commit 3bcbc20942db ("selftests/rseq: Play nice with binaries statically
linked against glibc 2.35+") which is now in Linus' tree introduced uses
of __weak but did nothing to ensure that a definition is provided for it
resulting in build failures for the rseq tests:

rseq.c:41:1: error: unknown type name '__weak'
__weak ptrdiff_t __rseq_offset;
^
rseq.c:41:17: error: expected ';' after top level declarator
__weak ptrdiff_t __rseq_offset;
                ^
                ;
rseq.c:42:1: error: unknown type name '__weak'
__weak unsigned int __rseq_size;
^
rseq.c:43:1: error: unknown type name '__weak'
__weak unsigned int __rseq_flags;

Fix this by using the definition from tools/include compiler.h.

Fixes: 3bcbc20942db ("selftests/rseq: Play nice with binaries statically linked against glibc 2.35+")
Signed-off-by: Mark Brown <broonie@kernel.org>
Message-Id: <20230804-kselftest-rseq-build-v1-1-015830b66aa9@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Pull Kselftest update from Shuah Khan:

 - several patches to fix incorrect kernel headers search path from
   Mathieu Desnoyers

 - a few follow-on fixes found during testing the above change

 - miscellaneous fixes

 - support for filtering and enumerating tests

* tag 'linux-kselftest-next-6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: (40 commits)
  selftests/user_events: add a note about user_events.h dependency
  selftests/mount_setattr: fix to make run_tests failure
  selftests/mount_setattr: fix redefine struct mount_attr build error
  selftests/sched: fix warn_unused_result build warns
  selftests/ptp: Remove clean target from Makefile
  selftests: use printf instead of echo -ne
  selftests/ftrace: Fix bash specific "==" operator
  selftests: tpm2: remove redundant ord()
  selftests: find echo binary to use -ne options
  selftests: Fix spelling mistake "allright" -> "all right"
  selftests: tdx: Use installed kernel headers search path
  selftests: ptrace: Use installed kernel headers search path
  selftests: memfd: Use installed kernel headers search path
  selftests: iommu: Use installed kernel headers search path
  selftests: x86: Fix incorrect kernel headers search path
  selftests: vm: Fix incorrect kernel headers search path
  selftests: user_events: Fix incorrect kernel headers search path
  selftests: sync: Fix incorrect kernel headers search path
  selftests: seccomp: Fix incorrect kernel headers search path
  selftests: sched: Fix incorrect kernel headers search path
  ...

Use $(KHDR_INCLUDES) as lookup path for kernel headers. This prevents
building against kernel headers from the build environment in scenarios
where kernel headers are installed into a specific output directory
(O=...).

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: linux-kselftest@vger.kernel.org
Cc: Ingo Molnar <mingo@redhat.com>
Cc: <stable@vger.kernel.org> # 5.18+
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Adapt to the rseq.h API changes introduced by commits
"selftests/rseq: <arch>: Template memory ordering and percpu access mode".

Build a new param_test_mm_cid, param_test_mm_cid_benchmark, and
param_test_mm_cid_compare_twice executables to test the new "mm_cid"
rseq field.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20221122203932.231377-20-mathieu.desnoyers@efficios.com

Adapt to the rseq.h API changes introduced by commits
"selftests/rseq: <arch>: Template memory ordering and percpu access mode".

Build a new basic_percpu_ops_mm_cid_test to test the new "mm_cid" rseq
field.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20221122203932.231377-19-mathieu.desnoyers@efficios.com

glibc-2.35 (upcoming release date 2022-02-01) exposes the rseq per-thread
data in the TCB, accessible at an offset from the thread pointer, rather
than through an actual Thread-Local Storage (TLS) variable, as the
Linux kernel selftests initially expected.

The __rseq_abi TLS and glibc-2.35's ABI for per-thread data cannot
actively coexist in a process, because the kernel supports only a single
rseq registration per thread.

Here is the scheme introduced to ensure selftests can work both with an
older glibc and with glibc-2.35+:

- librseq exposes its own "rseq_offset, rseq_size, rseq_flags" ABI.

- librseq queries for glibc rseq ABI (__rseq_offset, __rseq_size,
  __rseq_flags) using dlsym() in a librseq library constructor. If those
  are found, copy their values into rseq_offset, rseq_size, and
  rseq_flags.

- Else, if those glibc symbols are not found, handle rseq registration
  from librseq and use its own IE-model TLS to implement the rseq ABI
  per-thread storage.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220124171253.22072-8-mathieu.desnoyers@efficios.com