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From:   ebiederm@xmission.com (Eric W. Biederman)
To:     Marco Elver <elver@google.com>
Cc:     Arnd Bergmann <arnd@arndb.de>, Florian Weimer <fweimer@redhat.com>,
        "David S. Miller" <davem@davemloft.net>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Peter Collingbourne <pcc@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Alexander Potapenko <glider@google.com>,
        sparclinux <sparclinux@vger.kernel.org>,
        linux-arch <linux-arch@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux API <linux-api@vger.kernel.org>,
        kasan-dev <kasan-dev@googlegroups.com>
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        <m11rat9f85.fsf@fess.ebiederm.org>
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        <m1zgxfs7zq.fsf_-_@fess.ebiederm.org>
        <m1r1irpc5v.fsf@fess.ebiederm.org>
        <CANpmjNNfiSgntiOzgMc5Y41KVAV_3VexdXCMADekbQEqSP3vqQ@mail.gmail.com>
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Date:   Mon, 03 May 2021 15:25:14 -0500
In-Reply-To: <CANpmjNNyifBNdpejc6ofT6+n6FtUw-Cap_z9Z9YCevd7Wf3JYQ@mail.gmail.com>
        (Marco Elver's message of "Sat, 1 May 2021 18:24:24 +0200")
Message-ID: <m14kfjh8et.fsf_-_@fess.ebiederm.org>
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Subject: [PATCH 00/12] signal: sort out si_trapno and si_perf
Precedence: bulk


This is my attempt to sort out the ABI issues with SIGTRAP TRAP_PERF
before any userspace code starts using the new ABI.

The big ideas are:
- Placing the asserts first to prevent unexpected ABI changes
- si_trapno can become an ordinary fault subfield.
- Reworking siginfo so that si_perf_data can be a 64bit field.
- struct signalfd_siginfo is almost full

Marco I have incorporated your static_assert changes and built
on them to prevent having unexpected ABI changes.

The field si_trapno is changed to become an ordinary extension of the
_sigfault member of siginfo.

The code is refactored a bit and then si_perf_data is made a 64bit,
and si_perf_type is made distinct from si_errno.

Finally the signalfd_siginfo fields are removed as they appear to be
filling up the structure without userspace actually being able to use
them.

v1: https://lkml.kernel.org/r/m1zgxfs7zq.fsf_-_@fess.ebiederm.org

Eric W. Biederman (9):
      siginfo: Move si_trapno inside the union inside _si_fault
      signal: Implement SIL_FAULT_TRAPNO
      signal: Use dedicated helpers to send signals with si_trapno set
      signal: Remove __ARCH_SI_TRAPNO
      signal: Rename SIL_PERF_EVENT SIL_FAULT_PERF_EVENT for consistency
      signal: Factor force_sig_perf out of perf_sigtrap
      signal: Redefine signinfo so 64bit fields are possible
      signal: Deliver all of the siginfo perf data in _perf
      signalfd: Remove SIL_FAULT_PERF_EVENT fields from signalfd_siginfo

Marco Elver (3):
      sparc64: Add compile-time asserts for siginfo_t offsets
      arm: Add compile-time asserts for siginfo_t offsets
      arm64: Add compile-time asserts for siginfo_t offsets

 arch/alpha/include/uapi/asm/siginfo.h              |   2 -
 arch/alpha/kernel/osf_sys.c                        |   2 +-
 arch/alpha/kernel/signal.c                         |   4 +-
 arch/alpha/kernel/traps.c                          |  24 ++---
 arch/alpha/mm/fault.c                              |   4 +-
 arch/arm/kernel/signal.c                           |  37 +++++++
 arch/arm64/kernel/signal.c                         |  37 +++++++
 arch/arm64/kernel/signal32.c                       |  37 +++++++
 arch/mips/include/uapi/asm/siginfo.h               |   2 -
 arch/sparc/include/uapi/asm/siginfo.h              |   3 -
 arch/sparc/kernel/process_64.c                     |   2 +-
 arch/sparc/kernel/signal32.c                       |  35 +++++++
 arch/sparc/kernel/signal_64.c                      |  34 +++++++
 arch/sparc/kernel/sys_sparc_32.c                   |   2 +-
 arch/sparc/kernel/sys_sparc_64.c                   |   2 +-
 arch/sparc/kernel/traps_32.c                       |  22 ++--
 arch/sparc/kernel/traps_64.c                       |  44 ++++----
 arch/sparc/kernel/unaligned_32.c                   |   2 +-
 arch/sparc/mm/fault_32.c                           |   2 +-
 arch/sparc/mm/fault_64.c                           |   2 +-
 arch/x86/kernel/signal_compat.c                    |  20 ++--
 fs/signalfd.c                                      |  23 ++---
 include/linux/compat.h                             |  38 ++++---
 include/linux/sched/signal.h                       |  13 +--
 include/linux/signal.h                             |   3 +-
 include/uapi/asm-generic/siginfo.h                 |  57 +++++++----
 include/uapi/linux/signalfd.h                      |   4 +-
 kernel/events/core.c                               |  11 +-
 kernel/signal.c                                    | 113 +++++++++++++--------
 .../selftests/perf_events/sigtrap_threads.c        |  12 +--
 30 files changed, 402 insertions(+), 191 deletions(-)