[PATCH 00/12] signal: sort out si_trapno and si_perf

From: Eric W. Biederman
Date: Mon May 03 2021 - 16:25:26 EST



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_-_@xxxxxxxxxxxxxxxxx

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(-)