RFR: 8345296: AArch64: VM crashes with SIGILL when prctl is disallowed [v3]

[Aleksey Shipilev]

On Mon, 2 Dec 2024 17:21:19 GMT, Evgeny Astigeevich <eastigeevich at openjdk.org> wrote:

>> Aleksey Shipilev has updated the pull request incrementally with two additional commits since the last revision:
>> 
>>  - Handle zero too
>>  - Check get_current_sve_vector_length more comprehensively
>
> src/hotspot/cpu/aarch64/vm_version_aarch64.cpp line 452:
> 
>> 450:               "Disabling SVE. Specify -XX:UseSVE=0 to shun this warning.");
>> 451:       FLAG_SET_DEFAULT(UseSVE, 0);
>> 452:     } else if (vl < FloatRegister::sve_vl_min || ((vl % FloatRegister::sve_vl_min) != 0) || !is_power_of_2(vl)) {
> 
> I think `vl < FloatRegister::sve_vl_min` is redundant.
> It is covered by `vl % FloatRegister::sve_vl_min) != 0`.

I thought so too, but it is not, if `vl == 0`?

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

PR Review Comment: https://git.openjdk.org/jdk/pull/22479#discussion_r1866288142