RFR: 8255799: AArch64: CPU_A53MAC feature may be set incorrectly

[Anton Kozlov]

On Thu, 5 Nov 2020 15:23:24 GMT, Andrew Dinn <adinn at openjdk.org> wrote:

> > > At present reading /proc/cpuinfo that is the only reliable way I know of to identify whether dcpop is a supported feature (used to force persistence of data to memory). That is needed to support use of NVRAM-backed MappedByteBuffers.
> > 
> > 
> > I think that comes from `getauxval() & HWCAP_DCPOP`?
> 
> That assumes that HWCAP_DCPOP is defined on all the Linux/AArch64 releases we still need to build on. I am not sure if that is actually the case.

There is an established practice to define a value of HWCAP if one is not provided in the system headers https://github.com/openjdk/jdk/blob/master/src/hotspot/os_cpu/linux_aarch64/vm_version_linux_aarch64.cpp#L58, so it should be fine in any case.

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PR: https://git.openjdk.java.net/jdk/pull/1039