Re: [RFC PATCH 0/5] RSEQ selftests uplift for glibc-2.35 compatibility

[Mathieu Desnoyers <mathieu.desnoyers@efficios.com>]

[ I should really have CC'd the selftests maintainer and mailing list.
  Adding them in Cc to patch 0/5 to bring this series to their attention. ]

----- On Jan 17, 2022, at 3:39 PM, Mathieu Desnoyers mathieu.desnoyers@efficios.com wrote:

> glibc-2.35 will be released on 2022-02-01. It introduces a user-space ABI
> based on the thread pointer to access a reserved area of the TCB.
> 
> The rseq selftests originally expected the rseq thread data to sit in a
> __rseq_abi TLS variable.
> 
> Considering that the rseq ABI only allows a single rseq registration per
> thread, both cannot actively coexist in a process.
> 
> Adapt the selftests librseq implementation to become compatible with
> glibc-2.35. Keep a fallback implementation based on TLS available when
> an older glibc is detected.
> 
> Feedback is welcome,
> 
> Thanks,
> 
> Mathieu
> 
> Mathieu Desnoyers (5):
>  selftests/rseq: Remove useless assignment to cpu variable
>  selftests/rseq: Remove volatile from __rseq_abi
>  selftests/rseq: Introduce rseq_get_abi() helper
>  selftests/rseq: Introduce thread pointer getters
>  selftests/rseq: Uplift rseq selftests for compatibility with
>    glibc-2.35
> 
> tools/testing/selftests/rseq/Makefile         |   2 +-
> tools/testing/selftests/rseq/param_test.c     |   4 +-
> tools/testing/selftests/rseq/rseq-arm.h       |  32 ++--
> tools/testing/selftests/rseq/rseq-arm64.h     |  32 ++--
> .../rseq/rseq-generic-thread-pointer.h        |  25 +++
> tools/testing/selftests/rseq/rseq-mips.h      |  32 ++--
> .../selftests/rseq/rseq-ppc-thread-pointer.h  |  30 ++++
> tools/testing/selftests/rseq/rseq-ppc.h       |  32 ++--
> tools/testing/selftests/rseq/rseq-s390.h      |  24 +--
> .../selftests/rseq/rseq-thread-pointer.h      |  19 +++
> .../selftests/rseq/rseq-x86-thread-pointer.h  |  40 +++++
> tools/testing/selftests/rseq/rseq-x86.h       |  30 ++--
> tools/testing/selftests/rseq/rseq.c           | 161 +++++++++---------
> tools/testing/selftests/rseq/rseq.h           |  24 ++-
> 14 files changed, 302 insertions(+), 185 deletions(-)
> create mode 100644 tools/testing/selftests/rseq/rseq-generic-thread-pointer.h
> create mode 100644 tools/testing/selftests/rseq/rseq-ppc-thread-pointer.h
> create mode 100644 tools/testing/selftests/rseq/rseq-thread-pointer.h
> create mode 100644 tools/testing/selftests/rseq/rseq-x86-thread-pointer.h
> 
> --
> 2.17.1

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com