You need a completely different userland, compiled for x32 instead of amd64. Just running the default amd64 installation with a x32 kernel doesn't make it x32. EDIT: It would also work for just running x32 apps on an amd64 system, but then you only get the x32 benefits for those applications.

You don't need a whole x32 userland in order to be exploited. Just a single x32 binary executable that happens to not depend on on any external libraries.

You don't even need that. This can be done within a 64bit process using the x32 syscall number for recvmmsg.

-Brad

Ouch.

I did't mean for an exploit, I just meant that you don't have any use for a x32 kernel on your system if you don't have x32 apps and libraries (unless you build a statically-linked x32 app).

People are finally getting around to experimenting now there is gcc support. You need an x32 libc too, but you can use a chroot environment.

I realized after writing my post that you don't really need an entire system, just the x32 libraries (and not even those if you statically link your x32 application).