RFR: 8308503: AArch64: SIGILL when running with -XX:UseBranchProtection=pac-ret on hardware without PAC feature [v2]

[Hao Sun]

On Thu, 25 May 2023 09:04:15 GMT, Andrew Haley <aph at openjdk.org> wrote:

>> Hao Sun has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Disable ROP-protection if VMContinuations is on
>>   
>>   Virtual threads are proposed to be a permanent feature in JDK 21, and
>>   Arguments:enable_preview check no longer works. As an alternative, we
>>   check if VMContinuations is on.
>>   
>>   In this way, ROP protection is enabled only with VM options
>>   `-XX:UseBranchProtection=standard|pac-ret
>>   -XX:+UnlockExperimentalVMOptions -XX:-VMContinuations` on hardware with
>>   the support of PAC feature.
>
> src/hotspot/cpu/aarch64/vm_version_aarch64.cpp line 468:
> 
>> 466:     } else if (VMContinuations) {
>> 467:       // Not currently compatible with continuation freeze/thaw.
>> 468:       warning("ROP-protection is incompatible with virtual threads feature. Disabling ROP-protection.");
> 
> Suggestion:
> 
>       warning("ROP-protection is incompatible with VMContinuations. Disabling ROP-protection.");

Updated in the latest commit. Thanks.

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PR Review Comment: https://git.openjdk.org/jdk/pull/14095#discussion_r1205272927