kernel/linux.git/tools/testing/selftests/rseq/rseq.c, branch v6.3.6

selftests/rseq: Implement rseq numa node id field selftest

2022-12-27T11:52:11+00:00

Test the NUMA node id extension rseq field. Compare it against the value returned by the getcpu(2) system call while pinned on a specific core. Signed-off-by: Mathieu Desnoyers Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20221122203932.231377-7-mathieu.desnoyers@efficios.com

selftests/rseq: Use ELF auxiliary vector for extensible rseq

2022-12-27T11:52:11+00:00

Use the ELF auxiliary vector AT_RSEQ_FEATURE_SIZE to detect the RSEQ features supported by the kernel. Signed-off-by: Mathieu Desnoyers Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20221122203932.231377-6-mathieu.desnoyers@efficios.com

selftests/rseq: Fix: Fail thread registration when CONFIG_RSEQ=n

2022-12-27T11:52:10+00:00

When linking the selftests against a libc which does not handle rseq registration (before 2.35), rseq thread registration silently succeed even with CONFIG_RSEQ=n because it erroneously thinks that libc is handling rseq registration. This is caused by setting the rseq ownership flag only after the rseq_available() check. It should rather be set before the rseq_available() check. Set the rseq_size to 0 (error value) immediately after the rseq_available() check fails rather than in the thread registration functions. Signed-off-by: Mathieu Desnoyers Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20221122203932.231377-2-mathieu.desnoyers@efficios.com

selftests/rseq: check if libc rseq support is registered

2022-06-28T07:08:28+00:00

When checking for libc rseq support in the library constructor, don't only depend on the symbols presence, check that the registration was completed. This targets a scenario where the libc has rseq support but it is not wired for the current architecture in 'bits/rseq.h', we want to fallback to our internal registration mechanism. Signed-off-by: Michael Jeanson Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Mathieu Desnoyers Link: https://lore.kernel.org/r/20220614154830.1367382-4-mjeanson@efficios.com

selftests/rseq: Change type of rseq_offset to ptrdiff_t

2022-02-11T22:30:08+00:00

Just before the 2.35 release of glibc, the __rseq_offset userspace ABI was changed from int to ptrdiff_t. Adapt to this change in the kernel selftests. Signed-off-by: Mathieu Desnoyers Signed-off-by: Peter Zijlstra (Intel) Link: https://sourceware.org/pipermail/libc-alpha/2022-February/136024.html

selftests/rseq: Uplift rseq selftests for compatibility with glibc-2.35

2022-02-02T12:11:35+00:00

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

selftests/rseq: Remove volatile from __rseq_abi

2022-02-02T12:11:34+00:00

This is done in preparation for the selftest uplift to become compatible with glibc-2.35. All accesses to the __rseq_abi fields are volatile, but remove the volatile from the TLS variable declaration, otherwise we are stuck with volatile for the upcoming rseq_get_abi() helper. Signed-off-by: Mathieu Desnoyers Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20220124171253.22072-5-mathieu.desnoyers@efficios.com

selftests/rseq: introduce own copy of rseq uapi header

2022-02-02T12:11:33+00:00

The Linux kernel rseq uapi header has a broken layout for the rseq_cs.ptr field on 32-bit little endian architectures. The entire rseq_cs.ptr field is planned for removal, leaving only the 64-bit rseq_cs.ptr64 field available. Both glibc and librseq use their own copy of the Linux kernel uapi header, where they introduce proper union fields to access to the 32-bit low order bits of the rseq_cs pointer on 32-bit architectures. Introduce a copy of the Linux kernel uapi headers in the Linux kernel selftests. Signed-off-by: Mathieu Desnoyers Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20220124171253.22072-2-mathieu.desnoyers@efficios.com

selftests/rseq: remove ARRAY_SIZE define from individual tests

2021-12-11T00:51:03+00:00

ARRAY_SIZE is defined in several selftests. Remove definitions from individual test files and include header file for the define instead. ARRAY_SIZE define is added in a separate patch to prepare for this change. Remove ARRAY_SIZE from rseq tests and pickup the one defined in kselftest.h. Signed-off-by: Shuah Khan

rseq/selftests: Use __rseq_handled symbol to coexist with glibc

2019-05-07T21:31:46+00:00

In order to integrate rseq into user-space applications, expose a __rseq_handled symbol so many rseq users can be linked into the same application (e.g. librseq and glibc). The __rseq_refcount TLS variable is static to the librseq library. It ensures that rseq syscall registration/unregistration happens only for the most early/late caller to rseq_{,un}register_current_thread for each thread, thus ensuring that rseq is registered across the lifetime of all rseq users for a given thread. Signed-off-by: Mathieu Desnoyers CC: Shuah Khan CC: Carlos O'Donell CC: Florian Weimer CC: Joseph Myers CC: Szabolcs Nagy CC: Thomas Gleixner CC: Ben Maurer CC: Peter Zijlstra CC: "Paul E. McKenney" CC: Boqun Feng CC: Will Deacon CC: Dave Watson CC: Paul Turner CC: linux-api@vger.kernel.org Signed-off-by: Shuah Khan