RFR: 8253795: Implementation of JEP 391: macOS/AArch64 Port [v12]

[Anton Kozlov]

On Thu, 11 Mar 2021 20:27:51 GMT, Stefan Karlsson <stefank at openjdk.org> wrote:

>> The thread_bsd_aarch64.hpp describes a part of JavaThread, while this block belongs to Thread for now. Since W^X is an attribute of any operating system thread, I assumed Thread to be the right place for W^X bookkeeping. 
>> 
>> In most cases, we manage W^X state of JavaThread. But sometimes a GC thread needs the WXWrite state, or safefetch is called from non-JavaThread. Probably this can be dealt with (e.g. GCThread to always have the WXWrite state). But such change would be much more than a simple refactoring and it would require a significant amount of testing. Ideally, I would like to investigate this as a follow-up change, or at least after other fixes to this PR.
>
> Good point about Thread vs JavaThread. Yes, this can be looked into as follow-up cleanups.

The enhancement is tracked in https://bugs.openjdk.java.net/browse/JDK-8263492

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PR: https://git.openjdk.java.net/jdk/pull/2200