RFR: 8277204: Implementation of JEP 8264130: PAC-RET protection for Linux/AArch64 [v9]

[Alan Hayward]

On Fri, 10 Dec 2021 13:21:46 GMT, Andrew Haley <aph at openjdk.org> wrote:

>> Alan Hayward has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Default to building without branch-protection
>
> src/hotspot/cpu/aarch64/vm_version_aarch64.cpp line 419:
> 
>> 417:     if (UseROPProtection) {
>> 418:       warning("UseROPProtection specified, but not supported on this CPU.");
>> 419:       FLAG_SET_DEFAULT(UseROPProtection, false);
> 
> Suggestion:
> 
>       FLAG_SET_DEFAULT(UseROPProtection, true);
> 
> Given that the instructions used are in NOP space, this won't do any harm, and it will allow developers without PAC-enabled systems to see what code PAC would generate.

Ok, I think that's fine. How about on a non pac system allowing it for development only ?

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PR: https://git.openjdk.java.net/jdk/pull/6334