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

[Aleksey Shipilev]

On Mon, 2 Dec 2024 16:30:27 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> Maybe it's worth to move your new code under IF at line 518?
>> 
>> if (UseSVE > 0) {
>>   int vl = get_current_sve_vector_length();
>>   if ((FLAG_IS_DEFAULT(MaxVectorSize)) {
>>       MaxVectorSize = vl;
>>   }
>> 
>>   if (vl < 0) {
>>      warning("Unable to get SVE vector length on this system. Disabling SVE. Specify -XX:UseSVE=0 to avoid this warning.");
>>       FLAG_SET_DEFAULT(UseSVE, 0);
>>   } else if (MaxVectorSize < FloatRegister::sve_vl_min) {
>>       ...
>>   }
>
> Aha. I think the other way around: we need to do more checks right near the `_initial_sve_vector_length` inits. Hold on...

See new commit.

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PR Review Comment: https://git.openjdk.org/jdk/pull/22479#discussion_r1866173285