This series adds quality attributes to PTP Hardware Clock (PHC) timestamps, allowing userspace to obtain error bound, clock status, timescale, and raw counter values alongside timestamps in a single call.
Motivation ---------- The existing PTP APIs return timestamps without any indication of their quality. Applications that need clock accuracy and synchronization status commonly rely on external tools such as ptp4l, which implement synchronization logic and can export their measurement of clock accuracy. For managed PHC devices — such as the ENA network adapter, whose clock is synchronized by the device without userspace involvement — these tools are not available, and the existing APIs lack a way to report quality metrics to consumers of time. This was previously proposed as an RFC [1] with a single ioctl. Based on community feedback, the design was reworked to cover both the extended (multi-sample) and precise (cross-timestamp) paths, with a shared attributes structure. Design ------ This series introduces two new ioctls that extend the existing extended and precise timestamp paths with per-timestamp quality attributes: error bound (nanoseconds), clock synchronization status, timescale, and raw hardware counter values. A capability flag is added to ptp_clock_caps so userspace can discover attributes support. Patches 2-3 add testptp support for the new ioctls. Patch 4 implements the attributes for ptp_vmclock, reporting error bound, clock status, timescale, and raw counter values. Patches 5-7 implement the attributes for the ENA driver, reporting error bound from the device's PHC layer. v3: - Remove patch 5/8 from v2 (return-code bugfix) — sent separately as [PATCH net] to the net tree. - Zero-initialize struct ptp_clock_attributes in PTP core ioctl handlers to prevent stack leak of unset fields. (Simon Horman, sashiko) - ptp_vmclock: validate counter_period_shift < 128 to prevent undefined behavior on untrusted hypervisor input. (sashiko) - ptp_vmclock: add overflow check on err_hi * NSEC_PER_SEC to prevent silent wraparound producing erroneously small error bound. (sashiko) - ptp_vmclock: report PTP_TIMESCALE_TAI after tai_adjust() to avoid timescale mismatch. (sashiko) - ENA: set counter_id = 0, counter_value = 0 in gettimexattrs64 for defense-in-depth. (sashiko) v2: - Fix build bisectability: move ena_com.c consumer updates into patch 6/8 and ena_phc.c caller update into patch 7/8 so each patch compiles independently. - Add missing Cc for Amit Bernstein (co-author of ENA patches). [1] https://lore.kernel.org/netdev/[email protected]/ Arthur Kiyanovski (7): ptp: Add ioctls for PHC timestamps with quality attributes selftests/ptp: Extract print_system_timestamp helper in testptp selftests/ptp: Add testptp support for attributes ioctls ptp: ptp_vmclock: Implement attributes ioctls net: ena: Update PHC admin interface for error bound support net: ena: Add error bound to PHC communication layer net: ena: Implement gettimexattrs64 callback for PTP attributes .../device_drivers/ethernet/amazon/ena.rst | 2 + .../net/ethernet/amazon/ena/ena_admin_defs.h | 17 +- drivers/net/ethernet/amazon/ena/ena_com.c | 47 ++-- drivers/net/ethernet/amazon/ena/ena_com.h | 5 +- drivers/net/ethernet/amazon/ena/ena_debugfs.c | 3 + drivers/net/ethernet/amazon/ena/ena_phc.c | 64 ++++- drivers/ptp/ptp_chardev.c | 130 +++++++++- drivers/ptp/ptp_clock.c | 4 +- drivers/ptp/ptp_vmclock.c | 209 ++++++++++++++-- include/linux/ptp_clock_kernel.h | 30 +++ include/uapi/linux/ptp_clock.h | 225 +++++++++++++++++- tools/testing/selftests/ptp/testptp.c | 175 ++++++++++---- 12 files changed, 804 insertions(+), 107 deletions(-) -- 2.47.3
