[jdk17u-dev] RFR: 8309258: RISC-V: Add riscv_hwprobe syscall [v3]

[Robbin Ehn]

> Hi, please consider.
> 
> 
> RISC-V has many extensions and it's not feasible to set them correctly on the command line for users.
> There is no instruction to get the cpu, such as cpuid on x86.
> 
> 
> Still running tests, it will take a while.

Robbin Ehn has updated the pull request incrementally with two additional commits since the last revision:

 - Backport 311c7461c8c0f5f1524d409736e4cceca8de9000
 - Backport 876a725af95d65d59390c86bfec64c33cccbf53b

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

Changes:
  - all: https://git.openjdk.org/jdk17u-dev/pull/1942/files
  - new: https://git.openjdk.org/jdk17u-dev/pull/1942/files/4934d8ef..a52a69de

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=1942&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=1942&range=01-02

  Stats: 14 lines in 2 files changed: 10 ins; 1 del; 3 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/1942.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/1942/head:pull/1942

PR: https://git.openjdk.org/jdk17u-dev/pull/1942