[riscv-port-jdk11u:riscv-port] RFR: 8276799: Implementation of JEP 422: Linux/RISC-V Port [v5]

[kuaiwei]

> It's the initial patch based on https://github.com/openjdk/jdk17u-dev/pull/1427 , and revert patches not required in JDK11u. The testing is running on a linux riscv board. There are some failed cases and we are working on fix them , the progress will updated.
> 
> Thanks the contribution of OpenJDK community and hard working of @zhengxiaolinX .
> 
> - [x]  slowdebug/fastdebug/release build
> - [x] Benchmark: SPECJbb2015, Renaissance
> - [ ]  Tier1 tests
> - [ ] Tier2 tests
> - [ ] Tier3 tests
> - [ ] Tier4 tests

kuaiwei has updated the pull request incrementally with one additional commit since the last revision:

  8247533: SA stack walking sometimes fails with sun.jvm.hotspot.debugger.DebuggerException: get_thread_regs failed for a lwp
  
  Reviewed-by: sspitsyn, ysuenaga, dtitov

-------------

Changes:
  - all: https://git.openjdk.org/riscv-port-jdk11u/pull/3/files
  - new: https://git.openjdk.org/riscv-port-jdk11u/pull/3/files/4c23be66..70a060f7

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=riscv-port-jdk11u&pr=3&range=04
 - incr: https://webrevs.openjdk.org/?repo=riscv-port-jdk11u&pr=3&range=03-04

  Stats: 61 lines in 9 files changed: 34 ins; 0 del; 27 mod
  Patch: https://git.openjdk.org/riscv-port-jdk11u/pull/3.diff
  Fetch: git fetch https://git.openjdk.org/riscv-port-jdk11u.git pull/3/head:pull/3

PR: https://git.openjdk.org/riscv-port-jdk11u/pull/3