On Tue, 2 Mar 2021 21:19:18 GMT, Anton Kozlov <akoz...@openjdk.org> wrote:
>> Please review the implementation of JEP 391: macOS/AArch64 Port. >> >> It's heavily based on existing ports to linux/aarch64, macos/x86_64, and >> windows/aarch64. >> >> Major changes are in: >> * src/hotspot/cpu/aarch64: support of the new calling convention (subtasks >> JDK-8253817, JDK-8253818) >> * src/hotspot/os_cpu/bsd_aarch64: copy of os_cpu/linux_aarch64 with >> necessary adjustments (JDK-8253819) >> * src/hotspot/share, test/hotspot/gtest: support of write-xor-execute (W^X), >> required on macOS/AArch64 platform. It's implemented with >> pthread_jit_write_protect_np provided by Apple. The W^X mode is local to a >> thread, so W^X mode change relates to the java thread state change (for java >> threads). In most cases, JVM executes in write-only mode, except when >> calling a generated stub like SafeFetch, which requires a temporary switch >> to execute-only mode. The same execute-only mode is enabled when a java >> thread executes in java or native states. This approach of managing W^X mode >> turned out to be simple and efficient enough. >> * src/jdk.hotspot.agent: serviceability agent implementation (JDK-8254941) > > Anton Kozlov has updated the pull request incrementally with five additional > commits since the last revision: > > - Fix after JDK-8259539, partially revert preconditions > - JDK-8260471: bsd_aarch64 part > - JDK-8259539: bsd_aarch64 part > - JDK-8257828: bsd_aarch64 part > - Cleanup os_bsd_aarch64 signal handling src/hotspot/os_cpu/bsd_aarch64/os_bsd_aarch64.cpp line 207: > 205: // Enable WXWrite: this function is called by the signal handler at > arbitrary > 206: // point of execution. > 207: ThreadWXEnable wx(WXWrite, thread); Note that `thread` can be NULL here if the signal handler is running in a non-attached thread. ------------- PR: https://git.openjdk.java.net/jdk/pull/2200
