[RFC PATCH v7 0/7] Restartable sequences system call

[Mathieu Desnoyers]

Hi,

This is mostly a re-write of Paul Turner and Andrew Hunter's restartable
critical sections (percpu atomics), which brings the following main
benefits over Paul Turner's prior version (v2):

- The ABI is now architecture-agnostic, and it requires fewer
  instruction on the user-space fast path,
- Ported to ARM 32, in addition to cover x86 32/64. Adding support
  for new architectures is now trivial,
- Progress is ensured by a fall-back to locking (purely userspace)
  when single-stepped by a debugger.

This is v7, as it derives from my prior getcpu cache and thread local
ABI patchsets. You will find benchmark results in the changelog of
patch 1/7.

Feedback is welcome!

Thanks,

Mathieu


Mathieu Desnoyers (7):
  Restartable sequences system call
  tracing: instrument restartable sequences
  Restartable sequences: ARM 32 architecture support
  Restartable sequences: wire up ARM 32 system call
  Restartable sequences: x86 32/64 architecture support
  Restartable sequences: wire up x86 32/64 system call
  Restartable sequences: self-tests

 MAINTAINERS                                        |   7 +
 arch/Kconfig                                       |   7 +
 arch/arm/Kconfig                                   |   1 +
 arch/arm/include/uapi/asm/unistd.h                 |   1 +
 arch/arm/kernel/calls.S                            |   1 +
 arch/arm/kernel/signal.c                           |   7 +
 arch/x86/Kconfig                                   |   1 +
 arch/x86/entry/common.c                            |   1 +
 arch/x86/entry/syscalls/syscall_32.tbl             |   1 +
 arch/x86/entry/syscalls/syscall_64.tbl             |   1 +
 arch/x86/kernel/signal.c                           |   6 +
 fs/exec.c                                          |   1 +
 include/linux/sched.h                              |  68 ++
 include/trace/events/rseq.h                        |  60 ++
 include/uapi/linux/Kbuild                          |   1 +
 include/uapi/linux/rseq.h                          |  85 +++
 init/Kconfig                                       |  13 +
 kernel/Makefile                                    |   1 +
 kernel/fork.c                                      |   2 +
 kernel/rseq.c                                      | 243 +++++++
 kernel/sched/core.c                                |   1 +
 kernel/sys_ni.c                                    |   3 +
 tools/testing/selftests/rseq/.gitignore            |   3 +
 tools/testing/selftests/rseq/Makefile              |  13 +
 .../testing/selftests/rseq/basic_percpu_ops_test.c | 279 ++++++++
 tools/testing/selftests/rseq/basic_test.c          | 106 +++
 tools/testing/selftests/rseq/param_test.c          | 707 +++++++++++++++++++++
 tools/testing/selftests/rseq/rseq.c                | 200 ++++++
 tools/testing/selftests/rseq/rseq.h                | 449 +++++++++++++
 29 files changed, 2269 insertions(+)
 create mode 100644 include/trace/events/rseq.h
 create mode 100644 include/uapi/linux/rseq.h
 create mode 100644 kernel/rseq.c
 create mode 100644 tools/testing/selftests/rseq/.gitignore
 create mode 100644 tools/testing/selftests/rseq/Makefile
 create mode 100644 tools/testing/selftests/rseq/basic_percpu_ops_test.c
 create mode 100644 tools/testing/selftests/rseq/basic_test.c
 create mode 100644 tools/testing/selftests/rseq/param_test.c
 create mode 100644 tools/testing/selftests/rseq/rseq.c
 create mode 100644 tools/testing/selftests/rseq/rseq.h

-- 
2.1.4