RFR: 8367137: RISC-V: Detect Zicboz block size via hwprobe [v7]

[Dingli Zhang]

On Thu, 11 Sep 2025 01:28:33 GMT, Dingli Zhang <dzhang at openjdk.org> wrote:

>> Hi,
>> Can you help to review this patch? Thanks!
>> 
>> We can extends RISC-V hwprobe support to include `RISCV_HWPROBE_KEY_ZICBOZ_BLOCK_SIZE`.
>> The probed value is recorded in VM_Version::zicboz_block_size and then used to set the zicboz_block_size.
>> This ensures correct usage of the Zicboz extension, as block zeroing instructions operate on cache-line granularity.
>> 
>> FYI: https://docs.kernel.org/arch/riscv/hwprobe.html
>
> Dingli Zhang has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Unify variable names to correspond with comments

Thanks all for the review!
PS: hotspot:tier1 tested on OPi RV2 with `UseZicboz` (running kernel 6.15.2-spacemit-k1)

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PR Comment: https://git.openjdk.org/jdk/pull/27155#issuecomment-3283485565