Jeremie Courreges-Anglas <j...@wxcvbn.org> writes:
> On Tue, Feb 12 2019, Solene Rapenne <sol...@perso.pw> wrote:
>
>> brynet@ spotted that gzdoom wasn't W^X compliant due to a JIT engine
>> getting enabled automatically on amd64.
>>
>> This patch makes vm_jit knob at false by default instead of being true.
>> I did not see performance impact on my i7 when it's disabled, but this
>> could be interesting if someone could test it.
>>
>> Without the patch, it's possible to disable JIT with the parameter
>> '+vm_jit false'. While now we can still enable it with '+vm_jit true'
>> (with W^X violation).
>>
>> I don't know if we should let it as this and add WX_NEEDED or patch it
>> out so it doesn't WX by default?
>
> Note that there's a third approach for such ports: try to make the JIT
> W^X compliant. Here, it doesn't seem trivial (look for kVMExecutable).
>
> So your proposal makes sense to me, ok jca@ with a REVISION bump. If
> runtime still works, ofc, but I'll leave tests to actual users. :)
ok by me.
Timo
>
>> Index: patches/patch-src_scripting_vm_vmframe_cpp
>> ===================================================================
>> RCS file: patches/patch-src_scripting_vm_vmframe_cpp
>> diff -N patches/patch-src_scripting_vm_vmframe_cpp
>> --- /dev/null 1 Jan 1970 00:00:00 -0000
>> +++ patches/patch-src_scripting_vm_vmframe_cpp 12 Feb 2019 06:04:57
>> -0000
>> @@ -0,0 +1,16 @@
>> +$OpenBSD$
>> +
>> +disable JIT so it's W^X compatible
>> +
>> +Index: src/scripting/vm/vmframe.cpp
>> +--- src/scripting/vm/vmframe.cpp.orig
>> ++++ src/scripting/vm/vmframe.cpp
>> +@@ -49,7 +49,7 @@
>> + #endif
>> +
>> + #ifdef ARCH_X64
>> +-CUSTOM_CVAR(Bool, vm_jit, true, CVAR_NOINITCALL)
>> ++CUSTOM_CVAR(Bool, vm_jit, false, CVAR_NOINITCALL)
>> + {
>> + Printf("You must restart " GAMENAME " for this change to take
>> effect.\n");
>> + Printf("This cvar is currently not saved. You must specify it on the
>> command line.");
>>
