[aarch64-port-dev ] RFC: JEP draft JDK-8251280: macOS/AArch64 Port

[Anton Kozlov]

Hello,

Could you please look at and comment on a draft of JEP for macOS/AArch64 port[1]?

Usually, platform JEPs serve for integration rather than development. According
to current understanding, mac/aarch64 is an incremental extension to both
mac/x86 and linux-windows/aarch64. It is not expected that a considerable
rework will be required to implement mac/aarch64. 

The JEP initiates a discussion about mac/aarch64 as a supported platform also
to enable a certain workflow. If the mac/aarch64 platform would be accepted,
changes toward its support will be unblocked for review, testing, and
integration. For example, it was possible to isolate build system changes[2]
from the rest. Another example would be a solution to the W^X problem, parts of
which may be useful for OpenJDK in hardened runtime[3] configuration on mac/x86
(the one which will use MAP_JIT mmap() flag). Gradual changes integration is
hoped to reduce overall overhead for reviewers and enable more parties to
contribute. I find these goals desirable (at the expense of some overhead for
contributors), but the community may have more opinions.

I hope that the JEP draft covers all the important topics. If something is
missing or wrong, please let me know.

Thanks,
Anton

[1] https://bugs.openjdk.java.net/browse/JDK-8251280
[2] https://bugs.openjdk.java.net/browse/JDK-8250876
[3] https://developer.apple.com/documentation/security/hardened_runtime