[riscv-port-jdk11u:riscv-port] RFR: 8276799: Implementation of JEP 422: Linux/RISC-V Port [v6]

[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 three additional commits since the last revision:

 - 8287418: riscv: Fix correctness issue of MacroAssembler::movptr
   
   Reviewed-by: fjiang, yadongwang, fyang
 - 8285437: riscv: Fix MachNode size mismatch for MacroAssembler::verify_oops*
   
   Reviewed-by: shade, fyang
 - 8283737: riscv: MacroAssembler::stop() should emit fixed-length instruction sequence
   
   Reviewed-by: fyang, shade

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

Changes:
  - all: https://git.openjdk.org/riscv-port-jdk11u/pull/3/files
  - new: https://git.openjdk.org/riscv-port-jdk11u/pull/3/files/70a060f7..5cab06c6

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=riscv-port-jdk11u&pr=3&range=05
 - incr: https://webrevs.openjdk.org/?repo=riscv-port-jdk11u&pr=3&range=04-05

  Stats: 32 lines in 4 files changed: 10 ins; 0 del; 22 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