RFR: 8347343: RISC-V: Unchecked zicntr csr reads [v3]

[Robbin Ehn]

> Hi, please consider.
> 
> The rdinstret/rdcycle/rdtime are really useful and would be great to add in e.g. JFR.
> But as of now they are not used and zicntr is not yet in hwprobe therefore this patch just make sure they can't be used.
> 
> If we need them before hwprobe we can add a flag for manually enabling them.
> 
> Sanity tested.
> 
> Thanks!

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

  Remove header

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/23003/files
  - new: https://git.openjdk.org/jdk/pull/23003/files/d3d141a4..ad9c43ec

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=23003&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=23003&range=01-02

  Stats: 1 line in 1 file changed: 0 ins; 1 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/23003.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23003/head:pull/23003

PR: https://git.openjdk.org/jdk/pull/23003