search for: vm_prot_copy

...this. Memory is never allowed to be both writable and executable at the same time." That seems very sensible. So do the JIT engines just not work there now? Currently both MCJIT and JIT are using AllocateRWX which on that platform mmap's the memory as RX, then vm_protect's it as RX+VM_PROT_COPY, then vm_protect's it as RW. My best guess is that this is trying to set up something that's actually backed by two pages where whatever is written to the RW page will be copied to the RX page, though if that's possible it would seem to defeat the purpose of not allowing RWX. The case...

...re now? They work by allocating RW memory, then switching the permissions to RX before running any code stored there. That requires special process permissions. > > Currently both MCJIT and JIT are using AllocateRWX which on that platform mmap’s the memory as RX, then vm_protect’s it as RX+VM_PROT_COPY, then vm_protect’s it as RW. > > My best guess is that this is trying to set up something that’s actually backed by two pages where whatever is written to the RW page will be copied to the RX page, though if that’s possible it would seem to defeat the purpose of not allowing RWX. > &gt...

Hi Andy, On Nov 16, 2012, at 1:56 PM, "Kaylor, Andrew" <andrew.kaylor at intel.com> wrote: > Hi, > > Can anyone tell me something about mmap and vm_protect on ARM+Apple systems? Some. :) > > 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

Hi, Can anyone tell me something about mmap and vm_protect on ARM+Apple systems? 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