Does clocksource arch_sys_counter synchronize across CPUs?

[Huichun Feng]

Hi list,

AFAIK, one of the clocksource in arm64 (armv8.3, Rpi4) --
arch_sys_counter, uses a per-core register CNTVCT as the accessor.

And comes to consistency of CNTVCT's, after searching some of the
related manuals [0-2], I didn't find statements saying that it is
synchronize across CPUs. However, I've found a recent patch [3] says
that CNTVCT is synchronized in armv8.6.

So, does CNTVCT synchronize across CPUs in armv8.3?

thanks.
Huichun

[0] https://datasheets.raspberrypi.com/bcm2711/bcm2711-peripherals.pdf
[1] https://developer.arm.com/documentation/den0024/a/ARMv8-Registers/System-registers
[2] https://developer.arm.com/documentation/102379/0000/The-processor-timers?lang=en
[3] https://www.spinics.net/lists/arm-kernel/msg934605.html