[PATCH v8 0/7] Syscall User Dispatch

[Gabriel Krisman Bertazi <krisman@collabora.com>]

Hi,

This is v8 of syscall user dispatch.  Last version got some acks but
there was one small documentation fix I wanted to do, as requested by
Florian.  This also addresses the commit message fixup Peter requested.

The only actual code change from v7 is solving a trivial merge conflict
I myself created with the entry code fixup I made week and with
something else in the TIP tree.

I also shared this with glibc and there wasn't any complaints other than
the matter about user-notif vs. siginfo, which was discussed in v7 and
the understanding is that it is not necessary now and can be added
later, if needed, on the same infrastructure without a new api.

I'm not sure about TIP the rules, but is it too late to be queued for
the next merge window?  I'd love to have this in 5.11 if possible, since
it has been flying for quite a while.

This is based on tip/master.

As usual, a working tree with this patchset is available at:

  https://gitlab.collabora.com/krisman/linux -b syscall-user-dispatch-v8

Previous submissions are archived at:

RFC/v1: https://lkml.org/lkml/2020/7/8/96
v2: https://lkml.org/lkml/2020/7/9/17
v3: https://lkml.org/lkml/2020/7/12/4
v4: https://www.spinics.net/lists/linux-kselftest/msg16377.html
v5: https://lkml.org/lkml/2020/8/10/1320
v6: https://lkml.org/lkml/2020/9/4/1122
v7: https://lwn.net/Articles/837598/

Gabriel Krisman Bertazi (7):
  x86: vdso: Expose sigreturn address on vdso to the kernel
  signal: Expose SYS_USER_DISPATCH si_code type
  kernel: Implement selective syscall userspace redirection
  entry: Support Syscall User Dispatch on common syscall entry
  selftests: Add kselftest for syscall user dispatch
  selftests: Add benchmark for syscall user dispatch
  docs: Document Syscall User Dispatch

 .../admin-guide/syscall-user-dispatch.rst     |  87 +++++
 arch/x86/entry/vdso/vdso2c.c                  |   2 +
 arch/x86/entry/vdso/vdso32/sigreturn.S        |   2 +
 arch/x86/entry/vdso/vma.c                     |  15 +
 arch/x86/include/asm/elf.h                    |   2 +
 arch/x86/include/asm/vdso.h                   |   2 +
 arch/x86/kernel/signal_compat.c               |   2 +-
 fs/exec.c                                     |   3 +
 include/linux/entry-common.h                  |   2 +
 include/linux/sched.h                         |   2 +
 include/linux/syscall_user_dispatch.h         |  40 +++
 include/linux/thread_info.h                   |   2 +
 include/uapi/asm-generic/siginfo.h            |   3 +-
 include/uapi/linux/prctl.h                    |   5 +
 kernel/entry/Makefile                         |   2 +-
 kernel/entry/common.c                         |  17 +
 kernel/entry/common.h                         |  16 +
 kernel/entry/syscall_user_dispatch.c          | 102 ++++++
 kernel/fork.c                                 |   1 +
 kernel/sys.c                                  |   5 +
 tools/testing/selftests/Makefile              |   1 +
 .../syscall_user_dispatch/.gitignore          |   3 +
 .../selftests/syscall_user_dispatch/Makefile  |   9 +
 .../selftests/syscall_user_dispatch/config    |   1 +
 .../syscall_user_dispatch/sud_benchmark.c     | 200 +++++++++++
 .../syscall_user_dispatch/sud_test.c          | 310 ++++++++++++++++++
 26 files changed, 833 insertions(+), 3 deletions(-)
 create mode 100644 Documentation/admin-guide/syscall-user-dispatch.rst
 create mode 100644 include/linux/syscall_user_dispatch.h
 create mode 100644 kernel/entry/common.h
 create mode 100644 kernel/entry/syscall_user_dispatch.c
 create mode 100644 tools/testing/selftests/syscall_user_dispatch/.gitignore
 create mode 100644 tools/testing/selftests/syscall_user_dispatch/Makefile
 create mode 100644 tools/testing/selftests/syscall_user_dispatch/config
 create mode 100644 tools/testing/selftests/syscall_user_dispatch/sud_benchmark.c
 create mode 100644 tools/testing/selftests/syscall_user_dispatch/sud_test.c

-- 
2.29.2