[aarch64-port-dev ] RFR: 8253816: Switch to Exec W^X mode after JNI DetachCurrentThread

[Anton Kozlov]

JVM leaves Writeable mode for W^X after JNI detach thread. #9 describes an example when this breaks application expectations: a thread returns to a code generated by the application after JNI detach and crashes. Since the default mode is Executable, the change to Writeable is implicit and not expected.

The proposed solution is to ensure Executable mode after JNI detach.

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Commit messages:
 - JDK-8253816: Switch to Exec W^X mode after JNI DetachCurrentThread

Changes: https://git.openjdk.java.net/aarch64-port/pull/10/files
 Webrev: https://webrevs.openjdk.java.net/?repo=aarch64-port&pr=10&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8253816
  Stats: 160 lines in 3 files changed: 160 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/aarch64-port/pull/10.diff
  Fetch: git fetch https://git.openjdk.java.net/aarch64-port pull/10/head:pull/10

PR: https://git.openjdk.java.net/aarch64-port/pull/10