[PATCH v4 0/2] x86/tsc: Exempt recent UV systems from clocksource watchdog checks to avoid false positives.

[Dimitri Sivanich]

HPE UV hardware and firmware is designed to ensure a reliable and
synchronized TSC mechanism.  Comparing the TSC against secondary
clocksources can result in false positives due to variable access
latency caused by system traffic.  The best course of action against
these false positives has been found to simply disable watchdog
checking of the TSC.

Commits [1] and [2] were introduced to avoid an issue where the TSC
is falsely declared unstable by exempting qualified platforms of up
to 4-sockets from TSC clocksource watchdog checking.  Extend that
exemption to include recent and future UV platforms.

[1] commit b50db7095fe0 ("x86/tsc: Disable clocksource watchdog for TSC on qualified platorms")
[2] commit 233756a640be ("x86/tsc: Extend watchdog check exemption to 4-Sockets platform")

Dimitri Sivanich (2):
  Expose the uv_hub_type() interface
  Disable clocksource watchdog checking on recent and future UV
    platforms.

 arch/x86/include/asm/uv/uv_hub.h |  7 +++++++
 arch/x86/kernel/tsc.c            | 27 +++++++++++++++++++++------
 2 files changed, 28 insertions(+), 6 deletions(-)

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2.43.0