RFR: 8348384: RISC-V: Disable auto-enable Vector on buggy kernels [v2]

[Robbin Ehn]

> Hi please consider!
> 
> Linux kernels pre-6.9 can copy a dirty v-state during signal return path:
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/arch/riscv/kernel/signal.c?h=v6.13-rc1&id=c27fa53b858b4ee6552a719aa599c250cf98a586
> 
> We should not auto-enable vector with such kernel, as we must be able to receive signals during the execution of vector code.
> 
> Manual tested pre and post 6.9 as expected.
> 
> Thanks, Robbin

Robbin Ehn has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:

 - Update for merge
 - Merge branch 'master' into no_V_69
 - No V <6.9

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/23256/files
  - new: https://git.openjdk.org/jdk/pull/23256/files/d5d486a1..d7a645a6

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=23256&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=23256&range=00-01

  Stats: 6044 lines in 815 files changed: 2834 ins; 1213 del; 1997 mod
  Patch: https://git.openjdk.org/jdk/pull/23256.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23256/head:pull/23256

PR: https://git.openjdk.org/jdk/pull/23256