On Mon, 17 May 2021 at 21:58, Eric W. Biederman <ebiederm@xxxxxxxxxxxx> wrote: > > During the merge window an issue with si_perf and the siginfo ABI came > up. The alpha and sparc siginfo structure layout had changed with the > addition of SIGTRAP TRAP_PERF and the new field si_perf. > > The reason only alpha and sparc were affected is that they are the > only architectures that use si_trapno. > > Looking deeper it was discovered that si_trapno is used for only > a few select signals on alpha and sparc, and that none of the > other _sigfault fields past si_addr are used at all. Which means > technically no regression on alpha and sparc. > > While the alignment concerns might be dismissed the abuse of > si_errno by SIGTRAP TRAP_PERF does have the potential to cause > regressions in existing userspace. > > While we still have time before userspace starts using and depending on > the new definition siginfo for SIGTRAP TRAP_PERF this set of changes > cleans up siginfo_t. > > - The si_trapno field is demoted from magic alpha and sparc status and > made an ordinary union member of the _sigfault member of siginfo_t. > Without moving it of course. > > - si_perf is replaced with si_perf_data and si_perf_type ending the > abuse of si_errno. > > - Unnecessary additions to signalfd_siginfo are removed. > > v3: https://lkml.kernel.org/r/m1tuni8ano.fsf_-_@xxxxxxxxxxxxxxxxx > v2: https://lkml.kernel.org/r/m14kfjh8et.fsf_-_@xxxxxxxxxxxxxxxxx > v1: https://lkml.kernel.org/r/m1zgxfs7zq.fsf_-_@xxxxxxxxxxxxxxxxx > > This version drops the tests and fine grained handling of si_trapno > on alpha and sparc (replaced assuming si_trapno is valid for > all but the faults that defined different data). And just to clarify, the rest of the series (including static-asserts) for the next merge-window will be sent once this series is all sorted, correct? > Eric W. Biederman (5): > siginfo: Move si_trapno inside the union inside _si_fault > signal: Implement SIL_FAULT_TRAPNO > signal: Factor force_sig_perf out of perf_sigtrap > signal: Deliver all of the siginfo perf data in _perf > signalfd: Remove SIL_PERF_EVENT fields from signalfd_siginfo Looks good, thank you! I build-tested (defconfig -- x86_64, i386, arm, arm64, m68k, sparc, alpha) this series together with a local patch to pull in the static asserts from v3. Also re-ran perf_events kselftests on x86_64 (native and 32bit compat). Thanks, -- Marco
