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The zero variant is not something that many people spent time on, as there are limited use cases for the variant.</div>


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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> hotspot-dev <hotspot-dev-retn@openjdk.org> on behalf of Tanin Na Nakorn <tanin47@gmail.com><br>


<b>Sent:</b> Monday, October 6, 2025 8:54:19 PM<br>


<b>To:</b> Andrew Haley <aph-open@littlepinkcloud.com><br>


<b>Cc:</b> hotspot-dev@openjdk.org <hotspot-dev@openjdk.org><br>


<b>Subject:</b> Re: pthread_jit_write_protect_np(0) crashes if com.apple.security.cs.allow-jit isn't enabled on Mac (aarch64) (with a zero-variant JDK)</font>


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You don't often get email from tanin47@gmail.com. <a href="https://aka.ms/LearnAboutSenderIdentification" style="background:revert!important; color:revert!important; direction:revert!important; display:revert!important; font-size:revert!important; opacity:revert!important; visibility:revert!important">


Learn why this is important</a> </div>


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<div>Is there a plan to make the zero variant to comply with the no JIT definition from Apple? Or is it a no-go since JVM may depend heavily on this mechanism? (I'm unfamiliar with the area and would like to understand a bit more.)</div>


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<div>> Sure, just wrap the call in #ifndef ZERO.</div>


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<div>I tried commenting it out completely. It failed on being unable to reserve code cache. The mechanism seems to be essential.</div>


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<div>> That sounds right. Even with no compiler, AArch64 HotSpot still will generate an interpreter, and that's effectively JIT as far as Apple is concerned.</div>


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<div>Thank you so much. This insight is helpful.</div>


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<div dir="ltr" class="x_gmail_attr">On Mon, Oct 6, 2025 at 10:55 AM Andrew Haley <<a href="mailto:aph-open@littlepinkcloud.com">aph-open@littlepinkcloud.com</a>> wrote:<br>


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On 06/10/2025 18:30, Tanin Na Nakorn wrote:<br>


> 1. Does this mean a sandboxed Java app on Mac will always require <br>


> com.apple.security.cs.allow-jit? <br>


<br>


No, it just means that no one tried it.<br>


<br>


> Is there a way around this? For <br>


> example, is there a way to avoid using pthread_jit_write_protect_np(0) <br>


> in the zero variant?<br>


<br>


Sure, just wrap the call in #ifndef ZERO.<br>


<br>


> 2. It seems like the term JIT has different meanings for Java and Apple <br>


> where, for Java, it means not to use compiler1 and compiler 2. But, for <br>


> Mac, it means something else e.g. never use <br>


> pthread_jit_write_protect_np(0) and generate code.<br>


<br>


That sounds right. Even with no compiler, AArch64 HotSpot still will <br>


generate an interpreter, and that's effectively JIT as far as Apple is <br>


concerned.<br>


<br>


-- <br>


Andrew Haley  (he/him)<br>


Java Platform Lead Engineer<br>


<a href="https://keybase.io/andrewhaley" originalsrc="https://keybase.io/andrewhaley" rel="noreferrer" target="_blank">https://keybase.io/andrewhaley</a><br>


EAC8 43EB D3EF DB98 CC77 2FAD A5CD 6035 332F A671<br>


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