fix insufficient flushing on ARMv8.2+ #5257
Merged
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You need to use Point-of-Persistency flushes, defined specifically for our use case. This instruction has been split so Point-of-Coherency could be made lighter.
The documentation is clear here, and it's an obvious data loss bug, but no one of us had access to an ARMv8.2 machine to test before. No help has been offered by ARM (in stark contrast to IBM with ppc) thus there's no official support for PMDK on arm64 — but not flushing is severe enough to be fixed even in experimental code.
This change is