RFR: 8371869: RISC-V: too many warnings when build on BPI-F3 SBC [v3]

[Feilong Jiang]

On Thu, 20 Nov 2025 11:19:33 GMT, Fei Yang <fyang at openjdk.org> wrote:

>> Hi, please consider this riscv-specific change.
>> 
>> I witnessed 400+ warning messages when doing a native build on BPI-F3 SBC running kernel 6.6.63:
>> 
>> `OpenJDK 64-Bit Server VM warning: Cannot enable UseZvfh, it's missing dependent extension(s) v (disabled), Zfh (enabled)`
>> 
>> The warning messages indicate that we won't auto-enable extensions like `Zvfh` due to lack of vector support on old kernels.
>> I think these warning messages could be confusing to people. It might be more reasonable to just log these messages.
>> This also unifies the way of logging prefering `log_info`. It doesn't seem necessary to me to use `log_debug` in this case.
>> 
>> After this change, the log on BPI-F3 SBC looks like:
>> 
>> $ java -Xlog:all -version
>> 
>> ......
>> [0.011s][info][os         ] Linux kernels before 6.8.5 (current 6.6.63) have a known bug when using Vector and signals.
>> [0.011s][info][os         ] Vector not enabled automatically via hwprobe, but can be turned on with -XX:+UseRVV.
>> [0.011s][info][os,cpu     ] Enabled RV64 feature "a"
>> [0.011s][info][os,cpu     ] Enabled RV64 feature "c"
>> [0.011s][info][os,cpu     ] Enabled RV64 feature "d"
>> [0.011s][info][os,cpu     ] Enabled RV64 feature "f"
>> [0.011s][info][os,cpu     ] Enabled RV64 feature "i"
>> [0.011s][info][os,cpu     ] Enabled RV64 feature "m"
>> [0.011s][info][os,cpu     ] Enabled RV64 feature "Zba"
>> [0.011s][info][os,cpu     ] Enabled RV64 feature "Zbb"
>> [0.011s][info][os,cpu     ] Enabled RV64 feature "Zbs"
>> [0.011s][info][os,cpu     ] Enabled RV64 feature "Zfh"
>> [0.011s][info][os,cpu     ] Enabled RV64 feature "Zfhmin"
>> [0.011s][info][os,cpu     ] Disabled RV64 feature "Zvfh" (missing dependent extension(s): v (disabled), Zfh (enabled))
>> [0.011s][info][os,cpu     ] Enabled RV64 feature "marchid" (-9223372035378380799)
>> [0.011s][info][os,cpu     ] Enabled RV64 feature "mimpid" (1152921505839391232)
>> [0.011s][info][os,cpu     ] Enabled RV64 feature "mvendorid" (1808)
>> [0.011s][info][os,cpu     ] Enabled RV64 feature "satp_mode" (39)
>> [0.011s][info][os,cpu     ] Enabled RV64 feature "unaligned_scalar" (3)
>> [0.011s][info][os,cpu     ] Enabled RV64 feature "zicboz_block_size" (64)
>> [0.011s][info][os,cpu     ] Zifencei not found, required by Linux, enabling.
>> [0.012s][info][os,cpu     ] CPU: total 8 (initial active 8) spacemit,x60 rv64 rva rvc rvd rvf rvi rvm zba zbb zbs zfh zfhmin
>> ......
>
> Fei Yang has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Review

Marked as reviewed by fjiang (Committer).

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PR Review: https://git.openjdk.org/jdk/pull/28340#pullrequestreview-3500798209