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<p class="MsoNormal">Hi,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Can anyone tell me something about mmap and vm_protect on ARM+Apple systems?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I’m working on a new memory manager implementation for MCJIT and I want to replace calls to Memory::AllocateRWX with calls to Memory::allocateMappedMemory, possibly still with the RWX flags. However, looking at the Memory::AllocateRWX
implementation I see that it’s jumping through some hoops in the case where both ‘__APPLE__’ and ‘__arm__’ are defined.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I want to handle two cases:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="mso-list:Ignore">1)<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>Allocate memory as RWX, copy JITed code into it and execute it without ever touching the permissions again.<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="mso-list:Ignore">2)<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>Allocate memory as RW, copy JITed code into it and then set the permissions to RX before executing.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">This seems pretty straight-forward with the functions that use mmap and mprotect, but the AllocateRWX implementation leads me to believe that won’t work in the ARM+Apple case. I read some vm_protect documentation, but I can’t quite reconcile
it with the AllocateRWX implementation.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">My goal is to make sure the Memory::allocateMappedMemory and Memory::protectMappedMemory functions will work everywhere.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Any suggestions?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks,<o:p></o:p></p>
<p class="MsoNormal">Andy<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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